Talk:Steroid/Archive 2
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Conformational isomerism
Do steroids have any Conformational isomers as implied by Conformational isomerism ? Rod57 (talk) 12:42, 16 October 2010 (UTC)
- The tetracyclic core of steroids, the vast majority of which contain at least one trans ring fusion, do not have any conformational isomerism (the rings are locked together in such a way that they cannot conformationally interconvert; see trans decalin). The side chain that many (e.g., cholesterol) but not all steroids (e.g., estrone) are conformationally flexible and can adopt different conformational isomers. However since the substructure that is common to all steroids (the tetracyclic core) is not conformationally flexible, I think it is very misleading to say that steroids have conformational isomerism. Hence I would recommend that the link from conformational isomerism to steroid be removed. Cheers. Boghog (talk) 15:14, 16 October 2010 (UTC)
- This is answer does not capture the subject or direct the article to the broadly accepted (correct) understanding. A Nobel was awarded for the study of steroid conformation in the
1950s1960s, it was a subject of continuing intensive research through the 1980s, and it continues to receive periodic attention today. As well, it is a subject in advanced organic / physical organic chemistry course lectures in many good chemistry programs. I will post a series of citations, later, to make this clear. LeProf. — Preceding unsigned comment added by 50.179.92.36 (talk) 19:04, 25 November 2013 (UTC)- Let me clarify what I have written above. The core of steroids that contain a trans ring fusion do not have any significant conformationally flexibility. They are locked in a planar conformation. Depending on the substituents, the D-ring can wobble a bit but the pseudo rotational angles are nevertheless tightly constrained (see for example Radhakrishnan and Viswamitra (1991)). Changes from an sp3 to sp2 hybridization (e.g., 3-keto steroid, 4,5-Δ unsaturation) cause slight changes in the overall shape of the core, but the they retain a largely planar conformation. Finally which Nobel Prize are you referring to? This one? Boghog (talk) 21:03, 25 November 2013 (UTC)
- Further clarification. Steroids clearly have conformations and you are correct that an enormous amount of work has been devoted to their study. However the original question above concerns conformational isomerism (interconversion of conformations), not conformations per se. Hence I respectfully suggest that you have misinterpreted the original question. Boghog (talk) 21:32, 25 November 2013 (UTC)
- See further entire sections devoted to this perceived misinterpretation.
- This is answer does not capture the subject or direct the article to the broadly accepted (correct) understanding. A Nobel was awarded for the study of steroid conformation in the
Question - split Steroid vs. Steroidogenesis?
What do people think about having a separate Steroidogenesis article along with the main one for Steroid (and then ones for the different classes of hormones, etc)? I don't know if there is enough info there to warrant a separate article - especially if there are significant differences between humans and other species.. What think ye (I figure I'm maybe beating a very dead and archived horse here)? Jimw338 (talk) 19:34, 11 May 2013 (UTC)
- I think WP:WHENSPLIT applies here. At the moment, I don't think the size of the steroidogenesis section overwhelms the rest of the article. If and when this section is significantly expanded, then a split would probably be appropriate. I think the same would apply to the steroid hormones. Finally it should be noted there are often significant differences in the structure and function of steroid hormones in other species (e.g., compare cortisol vs. corticosterone, see also the taxonomical/functional section). Boghog (talk) 21:30, 11 May 2013 (UTC)
Missing start point in description of Mevalonate Pathway?
"The mevalonate pathway or HMG-CoA reductase pathway starts with *** and ends with dimethylallyl pyrophosphate (DMAPP) and isopentenyl pyrophosphate (IPP)." *** Looks as though something has got lost here. I don't have the knowledge to confidently fix it. Shannock9 (talk) 13:49, 23 November 2013 (UTC)
- Fixed Good catch. I am pretty sure the starting point is acetyl-CoA which I have added in this edit. Boghog (talk) 14:50, 23 November 2013 (UTC)
Immediate community action and subject matter experts requested to address broad issues with article structure and scope [LeProf]
I added the opening, very serious tag today, after editing elsewhere with the desire to send other chemical article readers to an authoritative general article on steroids.
On reading the Steroid article, I have to conclude that it would be much better, immediately and temporarily, as a very brief stub, until an authoritative outline can be developed and until that outline can be elaborated (see more below).
This is stated because the current article outline, content, and images fail to capture historical/contemporary roles of steroids in synthetic organic chemistry, biochemistry and cell biology, organismal biology and human therapeutics, and in regulatory matters relating their abuse. It is my belief that on arriving at an outline, all of these broad expertises are needed to create an acceptable general article on this interdisciplinary subject. This conclusion is offered as one with masters and doctoral degrees, and who has done chemical synthesis in academia and pharma, and has taught organic chemistry and biochemistry at universities and in a medical school.
The case for this is clear to anyone with a career in chemistry or biochemistry; it is also reasonably apparent in surveying the questions that have appeared on this page (which hint at the direction from which many readers will come to a general steroid article), and by review of the outline of the most authoritative general steroid article that appears on the web (Encyclopedia Britannica):
- Introduction
- History of steroids
- Steroid numbering system and nomenclature
- Methods of isolation
- Determination of structure and methods of analysis
- Partial and total syntheses of steroids
- Biological significance of steroids
- Pharmacological actions of steroids
- Biosynthesis and metabolism of steroids
- Structural relationships of the principal categories of steroids
Outline slightly redacted from http://www.britannica.com/EBchecked/topic/565825/steroid, accessed 24 November 2013. Entire article, approx. 7500 words.
In comparison, the outline of the wikipedia article, at same level of granularity to facilitate comparison, is:
- Structure and classification (taxonomic, functional, structural)
- Biosynthesis and metabolism (and pharmacology, inserted)
As further way to highlight the significant overlooked content, I did a cursory look to the Nobels issued which involved studies of steroids. Here is a beginning of a list (reference to which should be made in sections on the history, structure, chemical synthesis, and pharmacology):
- 1927, Chemistry, Heinrich Otto Wieland, constitution of the bile acids... of the sterols and their connection with the vitamins
- 1928, Chemistry, Adolf Otto Reinhold Windaus, constitution of the sterols and their connection with the vitamins
- 1939, Chemistry, Adolf Butenandt and Leopold Ruzicka, isolation and structural studiesof steroid sex hormones, and related studies on higher terpenes
- 1950, the Nobel Prize for Physiology or Medicine, Edward Kendall, Tadeus Reichstein, Philip Hench, on structure and biological effects of adrenal hormones
- 1969, Chemistry, Derek Barton, Odd Hassel, development of the concept of conformation and its application in chemistry, where a specific important emphasis was on the conformation of the "Steroid Nucleus"
[etc.]
Other omissions—e.g., such as the various ways in which different organisms have adapted the steriod nucleus to accomplish regulation of biomembrane structure and function, a subtopic in the Encycl Britan section, "Biological significance of steroids"—are far too numerous to even begin to list.
Further article "structural issues" include (a) the current article's extraction of images to define content (rather than critically outlining and defining content, then developing the necessary and appropriate images over time); this is highlighted in the current article by a tag indicating need to cleanup steroid image gallery, where organization/scope and specific selections are at issue, and (b) the article's presentation of steroid "categories" as an undeveloped list, significantly composed of links without much further explanation, where both content and format are questioned.
In short, I propose the best way to proceed to move this in a productive direction, would be to gather a consensus allowing:
- 1. immediate replacement of the article with a stub that could be mutually developed by the community, and eventually serve as the article lead,
- 2. development of a consensus, with further expert participation, of an authoritative outline for the article, and
- 3. roll out of the expanded article as each section achieves some degree of acceptable scope and sophistication of content (text and images).
I propose this for formal discussion and (with a nod to "wikitime"), near immediate action.
As noted, I am content expert (chemistry/medicinal chemistry). I have very little freely available time. Hence I'll only edit/act act in subject areas where I am approaching a relative expert, and will leave all article technical and formatting matters, and all political matters related to best wikipedia practice and consensus building to others here. (I have spent the time I can to make the case for removal to stub, and re-outlining and writing, and will not argue it any further.) It is up to the community to respond and act, in which case I will continue to contribute good specific chemical and biochemical content and guidance as I am able.
With regard, LeProf.
- While this article could certainly be improved, I do not think it qualifies for WP:BLOWITUP treatment. Your main criticism appears to be that it is missing material, not that the existing material is wrong. Hence I think that it can be easily improved through copyedit and expansion of the existing material. Also in an article about steroids, it is appropriate to have a number of graphics of structures. But I would agree that the number of structures depicted in this article is probably excessive and should be trimmed.
- The outline proposed above is useful. However I note that Wikipedia articles do not contain an introduction section. The lead serves as the introduction. Per MOS:HEAD, it is not necessary to repeat the title "steroid" in each of the section headings. Hence I would suggest the following outline:
- Nomenclature
- Types
- Biological significance
- Pharmacological actions
- Biosynthesis and metabolism
- Partial and total syntheses
- Determination of structure and methods of analysis
- Methods of isolation
- Finally what I think this article is most in need of is additional prose. Boghog (talk) 06:46, 25 November 2013 (UTC)
- I have edited the {{expert}} banner which contained a washing list of alleged problems with this article along with a long list experts. In particular, "regulatory matters relating their abuse" does not belong in a general article about steroids. This material is more appropriate for the anabolic steroids article where it is already discussed in detail. Boghog (talk) 07:05, 25 November 2013 (UTC)
- The outline provided is from Encyclopedia Britannica, and should not be used after swap of lead for intro, deletion of the word steroids from each outline entry, and reordering of entries—first, out of respect the copyrighted intellectual content of that competing online encyclopedia, and second because the expert that wrote the EB article followed a reasonable logic in his outline that is lost with a quick reordering to allow our current order to remain. We should thoughtfully develop our own outline as a community, and it should only be adopted after much further significant discussion. (I believe the eventual wikipedia article may have a similar flow to the EB, but have altered subject groupings, and perhaps a dozen or so outline points.)
- One such further point of content discussion is your case for omitting reference to anabolic steroids. I believe, as in the case of many other wikipedia articles, it is crucial to have a summary statement of the matter (relation of anabolic to other steroids, with a high level summary of the matters of regulation and abuse), accompanied by link to the further, more full exposition. This rather than having the parent steroid article devoid of any mention. My view is that as with other subjects, the parts need to seen in relation to the whole in the parent article (and steroid anabolism and catabolism are components of steroid metabolism).
- Because such discussions of major content change can take years, I continue to propose the redaction/strong paragraph substitution, and rewrite (not a blowup, but a substitute of high qualify brevity for very low quality expansiveness). While you focus on the missing material (2 of 10 competitor categories currently represented), there is also unacceptable conflation of material (pharmacology mixed into metabolism), jumbles of images in place of real content (where the outline of the real content should dictate chosen illustrations, and not vice versa), because such representations in chemistry are not secondary but primary (see Hoffmann R, Laszlo P (1991). "Representation in Chemistry". Angewandte Chemie International Edition in English. 30 (1): 1–16. doi:10.1002/anie.199100013.
{{cite journal}}
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ignored (help) ); moreover, there are many further deep issues with specific actual content items in place. While individual sentences may not be completely factually incorrect, they are often mis-ordered/mis-structured, and often so very incomplete to at least be naive as they stand alone (and in some cases actually incorrect). I for one cannot take the time to attempt to modify what is there into accurate scientific text. It is a waste of time to start from a bad outline to compose a good article. (I propose that the efficiency of process you eventually allow will also effect ability to recruit other content matter experts.) FInally, I would ask that description of what I expressed as being needed (the "washing list of alleged problems") remain in place for a few days, before it is changed—I was the one calling for the change, and it would be helpful for others to see the original description in the tag before that is "blown up". In any case, your subject replacements change the nature of the request, without discussion (e.g., MCB for biochemistry, and deletion of regulations and abuse). Thank you. LeProf.- I returned the call for experts banner, but edited it slightly to make it correspond to specific WikiProjects (red no longer appearing). It is important that this multidisciplinary subject receive expert advice across the spectrum indicated. An organic chemist writing on their importance in the history of total synthesis, biomimetic synthesis, and conformational studies should not guide the discussion on their role in regulation of membrane structure and trafficking or the comparative biochemistry of steroid biosynthesis, the biochemist and MCB expert writing the anabolism and catabolism subsections should not guide prose on the medical uses of steroids or the summary related to regulation and abuse, etc., etc., etc. People need to stick to writing about what they really know. Major issues in science articles often arise from individuals with limited breadth of knowledge contributing content that over time changes the nature of the article (e.g., through keyword searching and citation-mining at Pubmed, or similar mining practices in Wikipedia image collections). A rigorous, community-agreed outline with expert input is the key starting point (for discussion, and action). With regard, LeProf. — Preceding unsigned comment added by 50.179.92.36 (talk) 15:30, 25 November 2013 (UTC)
- It is important that you WP:BECONCISE, otherwise no one is going to pay any attention to what you write. Insisting that we have a large number of experts work on this article is both naive and fundamentally inconsistent with the way Wikipedia works. You are going to wait a very long time in order to assemble an expert panel of editors. In the meantime, why not make incremental improvements to the existing article? Finally the author of the Encyclopedia Britannica steroid article does not have a monopoly on logical order. The revised outline I proposed above is also logical. Boghog (talk) 16:04, 25 November 2013 (UTC)
- In re: your second reversion of the tag I placed. To be clear: I placed a tag for expert attention to the article, as a professional, laying out clearly and at length why the article needed significant change. You not only argue strongly that the article cannot change significantly and quickly—when five graduate students could knock off a superior draft in an afternoon—but also arrogantly revert the public, most easily viewed explanation that I posted of why it needed to change. You clearly have a deep personal interest in this article and the status quo. So be it, but it is simply not your place to immediately revert tag explanations from an original person posting, especially when asked politely not to do so. But I will not fight further with you. I will not give time to edit where individuals express dictatorial control over articles and other contributors' contributions—especially when they give evidence (see following) that their edits and control extend to areas where they are poorly qualified to make demands. Bottom line, the article is yours. Please see one last of the very many possible specific text corrections, above, regarding the hallowed area of steroid conformation. Good luck with your rule over this domain. LeProf.
- "laying out ... in length" – is precisely the problem that I have referred to above. An attention banner should be succinct as possible. Also please keep in mind {{sofixit}}. I have not demanded anything in what I have written above. Quite to the contrary, I have repeatedly demonstrated a willingness to work with other editors to improve this and other articles. I have merely requested brevity in what is written on talk pages and that contributions to Wikipedia articles conform to WP:MOS. Boghog (talk) 19:52, 25 November 2013 (UTC)
- "your subject replacements change the nature of the request, without discussion (e.g., MCB for biochemistry, and deletion of regulations and abuse)" – please note that there is no distinct Biochemistry WikiProject. Biochemistry falls under the umbrella of WP:MCB. Furthermore while this article should definitely contain a brief summary of anabolic steroids, information on the regulation and abuse of anabolic steroid is too detailed for this article. That detailed information belongs in the anabolic steroid article, not this article. Boghog (talk) 20:10, 25 November 2013 (UTC)
- Though you will undoubtedly revert this as well, I would ask you not to hide this most content rich section, out of your sense of insecurity. LeProf
- The reason I collapsed this is not insecurity, but because of its excessive length. Boghog (talk) 17:16, 29 November 2013 (UTC)
- Though you will undoubtedly revert this as well, I would ask you not to hide this most content rich section, out of your sense of insecurity. LeProf
- In re: your second reversion of the tag I placed. To be clear: I placed a tag for expert attention to the article, as a professional, laying out clearly and at length why the article needed significant change. You not only argue strongly that the article cannot change significantly and quickly—when five graduate students could knock off a superior draft in an afternoon—but also arrogantly revert the public, most easily viewed explanation that I posted of why it needed to change. You clearly have a deep personal interest in this article and the status quo. So be it, but it is simply not your place to immediately revert tag explanations from an original person posting, especially when asked politely not to do so. But I will not fight further with you. I will not give time to edit where individuals express dictatorial control over articles and other contributors' contributions—especially when they give evidence (see following) that their edits and control extend to areas where they are poorly qualified to make demands. Bottom line, the article is yours. Please see one last of the very many possible specific text corrections, above, regarding the hallowed area of steroid conformation. Good luck with your rule over this domain. LeProf.
Actual content of original request for expert attention, "Request for multidisciplinary rewrite of potential high-reader volume science article (above)"
The following is the actual content of the request for expert attention that I posted.
This article needs attention from an expert in chemistry, biochemistry, biology, medicine or law. The specific problem is: current article outline, content, and images do not capture historical/contemporary roles of steroids in synthetic organic chemistry, biochemistry, mol. cell and organismal biology, and human therapeutics, or the relation of their societal issues to these (all expertises needed). See the talk page for details. (November 2013) |
It appeared in a longer and somewhat problematic state (expert areas did not completely match WikiProject areas), and was reverted to its current state by Bohog. I edited the tag content and shortened it, also removing the mentioned problems, creating the text that appears above. This better version of my tag was again reverted by Bohog, who believes it good form to edit another's tag contents (despite clear, polite request not to do so).
The desired tag text appears here so that those who might become involved in editing the article can see all relevant information in Talk, and because I do not believe Bohog's imposed, shortened version captures the scope/magnitude of change that this important but largely misdirected article requires (see ED outline in earlier "Immediate community action..." Section above). LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 20:46, 25 November 2013 (UTC)
- Mountain, mole hill. While this article can certainly be improved, demanding immediate action and insulting editors is not the way to do it. I am removing the WP:DRIVEBYTAGGING entirely. Boghog (talk) 08:26, 27 November 2013 (UTC)
- Enjoy your personal steroid article. It is simply laughable as a scholarly general article on steroids, and will be as long as your personal inadequacies regarding control stand in the way of a commitment to true subject excellence. — Preceding unsigned comment added by 50.179.92.36 (talk) 14:49, 29 November 2013 (UTC)
- Thank you for your suggestion. When you believe an article needs improvement, please feel free to make those changes. Wikipedia is a wiki, so anyone can edit almost any article by simply following the edit this page link at the top.
The Wikipedia community encourages you to be bold in updating pages. Don't worry too much about making honest mistakes—they're likely to be found and corrected quickly. If you're not sure how editing works, check out how to edit a page, or use the sandbox to try out your editing skills. New contributors are always welcome. You don't even need to log in (although there are many reasons why you might want to). Boghog (talk) 15:43, 29 November 2013 (UTC)
- Thank you for your suggestion. When you believe an article needs improvement, please feel free to make those changes. Wikipedia is a wiki, so anyone can edit almost any article by simply following the edit this page link at the top.
Image-related tag that was removed...
The following image-related tag was removed by another editor, and is presented here in case others might have time and patience to attempt article edits in and around this controlling individual:
This section contains an unencyclopedic or excessive gallery of images. |
As I've already argued, the images appear to have been presented because they were available, rather than having images designed to support a text of soundly organized principles on the subject. As such, in this editor's opinion, the images remain an unstructured, un-nuanced and therefore pedagogically unhelpful hodge-podge unrelated to a well organized presentation of the subject.
As for the accusation of drive-by tagging: Tags were put in place by one with the necessary professional experience wishing to call attention to a very important article that was poorly structured and (to the extent content appeared on various subjects) poorly detailed. Tags appear to have been removed by the article owner because such criticism was unwelcome. The drive-by accusation is pejorative and off-point. No one of any substance in this field (or even the related teaching areas) will want to waste time arguing with the owner; that this potential editor has "driven by" was not original intention, and that it's occurring is the controlling editor's own fault.
- I am not the article owner and the only graphic that I created was the first one at the very top of this article. By all means, if you want to improve the graphics, please do so. I am not stopping you. As I have already stated above, I think the number of graphics in this article needs to be trimmed. Boghog (talk) 16:22, 29 November 2013 (UTC)
- Please continue. "And I removed the tag because... " — Preceding unsigned comment added by 50.179.92.36 (talk) 16:30, 29 November 2013 (UTC)
- Sure, no problem, I will continue. I removed the tag because the images, while their number may be excessive, are clearly related to the subject mater of this article and therefore are not indiscriminate. I have the necessary professional experience to make this judgement (graduate and post-doc in organic chemistry and 25 years experience in the pharmaceutical industry) and so does Wickey-nl (talk · contribs) who added the figures. Boghog (talk) 21:56, 29 November 2013 (UTC)
- Please continue. "And I removed the tag because... " — Preceding unsigned comment added by 50.179.92.36 (talk) 16:30, 29 November 2013 (UTC)
In re: conformation isomerism question...
Earlier Rod57 asked, do steroids have conformational isomers?
The answer, is yes, Rod57, steroids do have conformational isomers. And while the answer is complicated by all the many different specific molecules which fall under the rubric of "steroid", the beginnings of a full, correct answer can be found in the richness of steroid history and its old and continuing research literature.
Steroid conformations are important, at least, with regard to understanding
- (i) early and continuing structure determinations of steroid and related multi-cyclic terpenoid ring systems through spectroscopy (e.g., NMR spectroscopy) and chemical synthesis, and where these principles underpin general structure elucidation methods broadly applicable to organic natural products;
- (ii) the specific reactivities of frameworks that underlie steroid chemical and biological syntheses, interconversions, and degradative transformations;
- (iii) the intermolecular interactions that underlie steroid protein-ligand interactions, bile acid (and other steroid-small molecule) interactions and function, as well as generalized steroid- (and in particular sterol-) lipid packings involved in membrane structure and function, and
- (iv) in the history of chemistry, where academic and industrial steroid chemistry programs that included conformational analysis played an early critical role in defining modern organic chemical methods in structural study, chemical synthesis, and drug discovery.
Some references to begin your research might include (where, in longer PDFs, search "steroid"):
- Barton DHR (December 11, 1969). "The Principles of Conformational Analysis" (PDF). Nobel Lecture. Nobel Media AB.
- Boger DL. "Conformational Analysis" (PDF). Lecture Notes. Scrips Institute.
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(help) - Evans DA (September 29, 2006). "Conformational Analysis: Part–3" (PDF). Chem 206: Advanced Organic Chemistry. Harvard University.
search "A/B cis"
- Barton HR (1950). "The conformation of the steroid nucleus". Experientia. 6 (8): 316–20. doi:10.1007/BF02170915. PMID 15435524.
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ignored (help) - Prelog V. "Conformational analysis – Scope and present limitations" (PDF). IUPAC.
- Testa B, Vistoli G, Pedretti A (2013). "Organic Stereochemistry. Part 4". Helvetica Chimica Acta. 96 (4): 564–623. doi:10.1002/hlca.201200472.
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ignored (help)CS1 maint: multiple names: authors list (link) - Bagiński M, Tempczyk A, Borowski E (1989). "Comparative conformational analysis of cholesterol and ergosterol by molecular mechanics". Eur. Biophys. J. 17 (3): 159–66. doi:10.1007/BF00254770. PMID 2792025.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Sridharan R, Desai UR, Rao RM, Trivedi GK (1993). "Conformational analysis of A and B rings in 2-, 4-, and 6-bromosubstituted steroidal 4-en-3-ones by nuclear magnetic resonance" (PDF). Steroids. 58 (4): 170–7. doi:10.1016/0039-128X(93)90064-T. PMID 8493706.
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ignored (help)CS1 maint: multiple names: authors list (link)
This is a start. More work will not be given to this or the rest of the article, because (in this contributor's opinion), a single argumentative editor exerts control over the article as his own, far beyond his qualifications, making it a waste of scholarly time to attempt to make edits that might conflict with his determined sensibilities. LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 16:15, 29 November 2013 (UTC)
- The Evans DA (September 29, 2006). "Conformational Analysis: Part–3" (PDF). Chem 206: Advanced Organic Chemistry. Harvard University.
search "A/B cis"
link is instructive. While cis-decalin can interconvert conformations, steroids in which the rings A and B are fused cis cannot flip because of the B/C trans ring fusion. See last paragraph in Reusch W. "Steroids". Chemwiki. UC Davis.. I stand by my statement that the A/B/C/D core of steroids, even if the A/B ring is cis fused, do not possess any significant flexibility. Boghog (talk) 16:46, 29 November 2013 (UTC) - Thanks for supplying me a citation that strongly supports my original statement:
Boghog (talk) 21:19, 29 November 2013 (UTC)Each of the substituents in the steroidal nucleus changes the molecular geometry a little, but in spite of this fact the carbocylic nucleus is rather rigid and only the side chain is flexible (Stockton and Smith 1976; Dufoure et al. 1984).
— Bagiński et al., PMID 2792025 - Comments concerning each of the citations:
- Barton (Nobel lecture) – A/B trans ring fusion (XIII = XV; one conformation) and A/B cis ring fusion (XIV = XVI; one conformation)
- Boger – doesn't even mention steroids
- Evans – Rationalize the conformational flexibility of a A/B Trans vs. A/B Cis Steroid! – Trick question! The answer is neither is flexible! (see Bagiński and Reusch)
- Barton (Experientia) – behind a paywall
- Prelog et al. – mentions steroids only three times and doesn't say anything explicitly about their conformational properties
- Testa et al. – behind a paywall
- Bagiński – clear statement that the core ring system of steroids (e.g., cholesterol and ergosterol with cis A/B ring fusions) is inflexible
- Sridharan et al. – shows that with introduction of bulky bromo substituents, the conformation of the A-ring can wobble between half chair, sofa, and inverted half chair conformations but the A-ring is still largely planar in all three conformations while the B-ring retains a chair conformation and is hardly perturbed at all. Boghog (talk) 00:28, 30 November 2013 (UTC)
More needed content ... (secosteroids)
Another current glaring omission is the relationship of secosteroids (especially Vitamin D) to the parent class. LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 16:28, 29 November 2013 (UTC)
- Not as long as you hold tightly to the reins. The power lies not with those who take initiative, but with those in position to be first to revert—one of the many clear flaws of this system.
If you're ever in want of a real education, send your article off to chemists for whom you can muster respect, and see how they respond. Until then, enjoy the bliss arising from...LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 08:21, 30 November 2013 (UTC)
- Not as long as you hold tightly to the reins. The power lies not with those who take initiative, but with those in position to be first to revert—one of the many clear flaws of this system.
- Complete B.S. I have not reverted a single bit of article content that you have added. I have only edited, and then reverted what I thought were excessive and inappropriate comments in article message templates. Also your arrogance is astounding. I am a real chemist. Boghog (talk) 08:29, 30 November 2013 (UTC)
- One of many statements I made with unfortunate tone, retracted via strike through. LeProf
Final comments, importance of concepts/phenomena, steroid conformational isomerism
Final comments from me regarding this subject.
I stand by the topic's importance, stated in response to Rod57's question regarding whether steroids display conformational isomerism—and the broader question of the importance of conformational principles and equilibria in the function of steroids and history of their chemical study. In a narrow reading of the history and science, Boghog focuses on the ABCD ring rigidity of some steroids, and answers Rod57 with a "no", and advocates removal of a link to further understand the subject as "misleading". My answer is simply, yes, Rod57, steroids do have conformational isomers, and they are important for various reasons.
The reasons for importance are introduced in my four Roman-numerals above, in the Talk Section entitled "In re: conformation isomerism question..." (16:15, 29 November 2013).
This is to specifically say, when Boghog writes:
- "The tetracyclic core of steroids... do not have any conformational isomerism (the rings are locked together in such a way that they cannot conformationally interconvert; see trans decalin)."
He is correct about a subset of steroids, in a particular temperature range, and viewing them as static structures and not as reactive chemical systems; hence it is simplistic, and so is misleading/mistaken, both to generalize from that subset of steroids to all steroids, and to deny the importance of conformational isomerism to the study of steroids. The references to the decalins is also somewhat misleading (as they do exhibit conformational equilibria, esp. cis-), and cis- and brominated and other "non-simple" steroids are still steroids. The thrust is also poor for use of the absolute ("do not have any"), and the implied generalization from the tetracyclic core to the operational conclusion (remove the conformational analysis link) that impacts an article aimed at an array of related molecules. Bromosteroids and secosteroids are steroids, and despite obfuscation, it's quite clear that they display important conformational flexibility (e.g., see Sridharan quoted, below).
- "...since the substructure that is common to all steroids (the tetracyclic core) is not conformationally flexible, ... it is very misleading to say that steroids have conformational isomerism."
...is again incorrect because this again reduces a complex reality through generalization, such that many important molecules and phenomena are excluded.
Finally, and factually:
- 1. The statement above that Boger (Stanford, Advanced OChem Lecture Notes) "doesn't even mention steroids" is again incorrect. See p. 3 of the linked Boger material. He cites Barton's steroid work there. My calling attention to this followed my promise to provide evidence that conformational analysis of steroids finds its way into the best Adv OChem grad and undergrad materials. Same is true of the Evans materials.
- 2. The respondent's statement above, reducing Barton's work—that resulted in a Nobel for conformational analysis, including related to steroids—to "A = B, I'm right, Q.E.D.", is a further laughably incorrect simplification and misreading of the work and history.
- 3. The response to Evans student problem above is again simply incorrect; it is not a "trick question". To cite the fine Reusch source Boghog mis-supplies in support of his errant "neither is flexible!" conclusion: "Conformational descriptions of cis- decalin are complicated by the fact that two energetically equivalent fusions of chair cyclohexanes are possible, and are in rapid equilibrium as the rings flip from one chair conformation to the other." Granted, this picture changes with the fusion of the C-ring, but this is the point (that the matter needs discussion, not a superficial "all rigid, nothing more to be said" treatment), both in relation to tetracyclic steroid structure, synthesis, and function, but also in relation to secosteroids, etc.
- 4. The indirect referencing of Reusch/MSU's online OChem (http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/lipids.htm#steroid) is welcome, as a general, excellent, non-subscription-requiring citation. But, as noted, it simply does not make the absolute and exclusionary point (that conformations are unimportant in steroids), in particular as noted above, or in general. How does this venerable teacher of OChem support absolute and marginalizing statements when he spends three paragraphs discussing steroid substructures vis-a-vis principles underlying their conformational equilibria? Granted, they apply only to some, and not all steroids, but a general article about steroids is ... about all steroids. And the fact that he takes three paragraphs to arrive at the conclusion that boat conformers are higher energy relative to chairs, making them "minor components in the overall ensemble of conformations available to these molecules" clearly points to (a) the availability of conformers even in this one subset of rigid steroids, and (b) to the importance of a deep understanding of principles of steroid conformational analysis in understanding their synthesis, structure, and function. Not only the "what", but the "why" is important here. Perhaps Emer Prof Reusch should be sent the steroids article, and this dialog, and asked his opinion? (Someone earlier was speaking of the need for further expert opinion.)
- 5. The references to the work of Bagiński et al and Sridharan et al were offered as evidence of continuing interest in steroid conformation in modern research, and even if only the abstracts are read, they make this point clearly.
- 6. Bagiński's work is misrepresented above. When Bagiński writes "The latter [steroids]... have different conformations of the side chain as well as different conformations of rings A and D" and further writes "The relatively rigid side chain of ergosterol (stretched molecule) in comparison with the flexible side chain of cholesterol (bent molecule), allows better intermolecular contact of the first sterol molecule with a polyene macrolide and in consequence facilitates complex formation involving Van der Waal's forces", he is clearly not supporting an absolute pronouncement about the lack of steroid conformational equilibria.
- 7. Sridharan's work is also misrepresented above, with regard to the stated absolutes. When Boghog summarizes Sridharan, saying that a steroid in question "is still largely planar in all three conformations while the B-ring retains a chair conformation and is hardly perturbed at all", he reports selectively and self-affirmingly, arriving at a conclusion distinct from that presented by the author in his abstract: that brominated steroids differ in conformation from their protio-parents. To whit: "Bromosubstitution at the 2α position is responsible for the inversion of the A ring to inverted 1β,2α-halfchair conformation. The electronic interaction between 4-bromine and carbonyl oxygen distorts the A-ring conformation further. Inversion of the A ring has a concomitant effect of distortion in the chair form of the B ring." (abstract, Sridharan et al, cited and linked above). Simply put, different conformations exist for these specific steroids relative to their parent protio-steroids.
Bottom line, I have not argued against the relative rigidity of part of many steroid ring systems, but that the respondent, apparently one knowledgable about molecular biology and informatics, was incorrect in the bold conclusion that steroids do not display conformational isomers, and that to link to discussions of conformational isomerism would be misleading. The citations I provided as first support of the conclusion that conformational matters should be discussed were selectively, and self-affirmingly read and so not accurately reported. In particular, the Boghog summaries were handled in a very intellectually disingenuous manner regarding the main points (whether conformational isomers occur, and whether the concept's importance was important enough that mention should be made).
My informed opinions: Is it ""very misleading to say that steroids have conformational isomerism""? No, it is a misleading oversimplification to say they do not. Do steroids display conformational isomerism? Yes, from the above citations and many others, clearly, yes. Is conformational isomerism is an important concept to discuss in the contect of the chemistry portion of an article on steroids? Again, Yes. All of good OChem, history, and even membrane biophysics is arrayed against the argument to the contrary. I would have to begin to laugh at the time being consumed at this silly arguing, if the contrary attitudes and commitments weren't so filled with pathos. One may occasionally miss the forest for the trees, but one mustn't climb a tree and insist it is a forest. LeProf. — Preceding unsigned comment added by 50.179.92.36 (talk) 10:36, 30 November 2013 (UTC)
- In re: 1. Regardless, the Lecture Notes themselves do not mention steroids. Boghog (talk) 11:18, 30 November 2013 (UTC)
- In re: 2. An obvious and straight forward conclusion. Boghog (talk) 11:18, 30 November 2013 (UTC)
- In re: 3. In order for the cis A/B rings to flip, the B-ring must flip from one chair conformation to another. However the flipping of the B-ring is made impossible by the trans B/C-ring fusion. Hence steroids with cis A/B ring and trans B/C ring fusions have rigid cores. The original discussion above was about tetracyclic steroids, not tricyclic secosteroids that lack a B-ring. Boghog (talk) 11:18, 30 November 2013 (UTC)
- In re: 4. See comment above. Boghog (talk) 11:18, 30 November 2013 (UTC)
- In re: 6. He is supporting conclusion that steroids like cholesterol with cis A/B ring and trans B/C ring fusions have rigid cores. Boghog (talk) 11:18, 30 November 2013 (UTC)
- In re: 7. Again, with unusual substitution patterns, some A-rings do possess some flexibility. Boghog (talk) 11:18, 30 November 2013 (UTC)
- My formal training is in organic chemistry, not molecular biology or informatics and I have taken undergraduate and graduate course in conformational analysis and steroid synthesis. I know what I am talking about. Please WP:AGF.
- I have not argued that the steroid nucleus is completely rigid, but for the most common types of steroids without unusual substitution, to a first approximatation, they are rigid. For a Wikipedia article, it is important that we get the big picture right in the lead. Details like A- and D-ring conformational flexibility are more appropriate for a section dealing with conformational flexibility later in the article.
- Big picture: "I have not argued against the relative rigidity of part of many steroid ring systems" – "very misleading to say that steroids have conformational isomerism". When one focuses on the forest instead of the trees, these two statements are roughly equivalent. Good, then we in agreement! End of discussion. Boghog (talk) 10:58, 30 November 2013 (UTC)
- I disagree with your big-picture-rough-equivalence, and note you passed over the survey of misconstrued references. But good, so you retract, that "...since the substructure that is common to all steroids (the tetracyclic core) [sic.] is not conformationally flexible ... it is very misleading to say that steroids have conformational isomerism"? And since you have the credentials, you will be developing a good, hisorically-rooted section on conformational analysis within the article (and re-introducing the link to conformational isomerism)? I'll hope, but expect not. And congrats on the OChem training; it is a fine heritage we share, and UWM is a fine school. Perhaps the time in OChem residence is where "I can't be wrong" leanings crept in. Apologies to accuse you of being a biologist. LeProf. — Preceding unsigned comment added by 50.179.92.36 (talk) 11:17, 30 November 2013 (UTC)
- Thank you for your kind words. One minor correction. I was an undergraduate at UW Madison, not UWM (although I did take one summer course at the later). Boghog (talk) 11:25, 30 November 2013 (UTC)
- At risk of further inflaming passions, I collected your interspersions and pasted them together (above, with other comments at same timestamp), for you to edit and expand as you see fit. My understanding is that interspersing in another's talk is not acceptable here. Even more so given the history of our discourse. Have at me, but at the end of my block.
- I've never made any statement about where steroid conformation analysis/discussion (and links to broader such discussions) should appear, and have no strong opinion on this. But since the article lead is intended to capture later text, I still can't imagine supporting any absolute statement in the lead that does not capture the complexity of all steroids. Here and otherwise, I'm not sure if/how we are in agreement. I'll wait and see. I will say I'm still not disposed to attempt to be involved in the article. My original critique of it remains, and the insertion of the EB headings does not move it much forward. (My view is that the article should always be ready for prime time, hence the failed "replace imm. with short, high quality" argument.) The hesitation is all the more pronounced, since our areas of expertise overlap, rather than compliment. Not easy for two old dogs to co-teach soph OChem.
- Finally, as a UIUC and UChgo product (non-cheesehead) I can be forgiven I hope for initially using UWM for Madison. Fan of both, and hosted UMW Cap'n Cook for a seminar years back. And congrats on surviving pharma, if indeed this was the case. I left the midwest's premier one, for academia, before holding on to one's medichem position became such a tenuous prospect. As for WP:AGF, please realize all this began with reversions of tags (!), and wholesale rejection of a restructuring of the article. For these, I am still toasting cheese. Perhaps we are both too old for this. (Earlier today I was on citizendium and scholarpedia.) And please, find "steroids" on Boger p. 3, so I am not forced to presume early onset dementia, for one or the other of us. LeProf
There is mixed opinion on interleaving comments. I tend to agree with this one:
On Wikipedia, clarity within complex threads is important, and interleaving, if properly done, is an effective means to that end and is best practice.
— User:Elvey
But I will leave them unthreaded.
Please note that the discussion above was prompted by an internal Wikilink from the see also section of conformational isomerism to this article. I thought then and I still think steroids, because of the relative rigidity of their cores, are not a very good example of molecules that display conformational isomerism. The only consequence of that original discussion was removal of the internal link in this edit.
I now see that on page three of the Boger lecture notes is mentioned Derck Barton and steroids. I missed this in part because the text in this box was a graphic that cannot be found using a text search.
I am still hanging on in the pharmaceutical industry, but it is still a very tough business to be in. Finally I would like to point out there is absolutely nothing wrong with being a biologist. In stark contrast to Citizendium , credentials on Wikipedia are irrelevant. The way one gains respect with fellow editors is the quality of your contributions. The only reason I pointed out my background was it becoming clear that is the only way I could get your attention. It should not have to be like this. Cheers. Boghog (talk) 19:49, 30 November 2013 (UTC)
Another reference with a potentially useful outline / steroid categorization
Lednicer D (2011). Steroid Chemistry at a Glance. Hoboken: Wiley. doi:10.1002/9780470973639. ISBN 978-0-470-66085-0.
LeProf
- Thanks, that source looks like a very good review. Boghog (talk) 10:07, 1 December 2013 (UTC)
On J Cornforth's portion of the prize in 1975, for developing methods to determine the stereochemical course of biosyntheses, including cholesterol from mevalonic acid via squalene
http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1975/press.html LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 09:57, 1 December 2013 (UTC)
- Thanks again. I added the above to the Steroid#History section. Boghog (talk) 10:17, 1 December 2013 (UTC)
On RB Woodward's prize in 1965, for outstanding achievements in organic synthesis, including of cholesterol, cortisone, and lanosterol
http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1965/press.html
Reference with reasonable structural classification of steroids, with helpful image set
http://www.glowm.com/resources/glowm/cd/pages/v5/v5c001.html#bas [ see first section link ] LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 10:23, 1 December 2013 (UTC)
Probably the single best guide to continuing steroid synthetic work (blog), and a very good citn regarding the history (to date) of steroid synthesis, esp. biomimetic
LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 11:03, 1 December 2013 (UTC)
Umesh Desai, Prof Medichem at VCU, on prevalent ring-fusion isomer examples in steroid (for confirmation, follow-up)
- trans-trans-trans: most natural and synthetic steroids, e.g., 5a-dihydrotestosterone)
- cis-trans-trans, some natural steroids, e.g., cholic acids
- cis-trans-cis, few natural steroids, e.g. cardiac glycosides
http://www.people.vcu.edu/~urdesai/intro.htm#Conformation
LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 20:23, 1 December 2013 (UTC)
This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 | Archive 4 |
NLM MeSH categories, steroids
- Polycyclic Compounds [D04]
- Bridged Compounds [D04.075]
- Macrocyclic Compounds [D04.345]
- Polycyclic Hydrocarbons, Aromatic [D04.615]
- Steroids [D04.808]
- Androstanes [D04.808.054]
- Bile Acids and Salts [D04.808.105]
- Cardanolides [D04.808.155]
- Cholanes [D04.808.221]
- Cholestanes [D04.808.247]
- Cyclosteroids [D04.808.294]
- Estranes [D04.808.365]
- Gonanes [D04.808.451]
- Homosteroids [D04.808.496]
- Hydroxysteroids [D04.808.528]
- Ketosteroids [D04.808.578]
- Norsteroids [D04.808.668]
- Pregnanes [D04.808.745]
- Sapogenins [D04.808.795]
- Secosteroids [D04.808.812]
- Steroids, Brominated [D04.808.875]
- Steroids, Chlorinated [D04.808.883]
- Steroids, Fluorinated [D04.808.908]
- Steroids, Heterocyclic [D04.808.925]
http://www.nlm.nih.gov/cgi/mesh/2011/MB_cgi?mode=&term=Steroids&field=entry#TreeD04.808
LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 22:41, 1 December 2013 (UTC)
Tabulation of images currently appearing, by various categories, to reflect current vs. possible future image design
I wrote this tabulation up in full, only to have a browser issue resulting in loss of the material. Hence, some details and all disclaimers—no time to reproduce. Point here is to give other editors a relative sense of current image coverage and priorities, by comparing what images are here, to what images might appear. Counts are of number of presented images, and exclude the complex steroidogenesis figure that currently appears small in size.
There are currently 14 structure images appearing in 13 panels, 12 with 1 structure per panel (one with 2, one with 1 in scheme). The number of each structure type appearing is given in parentheses, where the image illustrates:
- the ring letter convention (2 images), or the ring numbering convention (3 images);
- a planar perspective drawing/representation (10 images), chair-boat representation (0 images), or non-sterochemical or misc. representation (4 images);
- stick representation (1 image), a space-filling/other such uniquely informative representations (0 images), line-angle representation with terminal CH3/Me (0 images), or line-angle representation without terminal CH3/Me (10 images);
- a hydrocarbon-type structure (5 images), C-3 sterol (5 images), A-ring ketosteroid (2 images), C-17 ketosteroid (2 images), bile acid (1 image), aromatic steroid (0 images), secosteroid (0 images), halogenated steroid (0 images), etc.;
- a framework example: gonane, C17 (3 images), estrane, C18 (0 images), androstane, C19 (1 image), pregnane, C21 (1 image), cholane, C24 (1 image), cholestane, C27 (4 images), or other framework: C29 (2 images, lanosterol, sisosterol);
- a vertebrate steroid example (5 images), or a non-vertebrate steroid example (1 image), e.g., a phyto/algal steroid (1 image), fungal steroid (0 images), bacterial steroid (0 images), etc.;
- a steroid hormone precursor, e.g., lanosterol, cholesterol (2 images), or an androgen (1 image), or an estrogen (0 images), or a progestagen (1 image), or a mineralocorticoid, e.g. aldosterone, deoxycorticosterone, fludrocortisone (0 images), or a glucocorticoid, e.g., prednisone, prednisolone (0 images), or a mixed-function corticosteroid, e.g., cortisol, cortisone (0 images);
- a key oral or inhaled steroid drug, e.g., prednisone, methyl-prednisolone, and prednisolone, or ciclesonide, fluticasone, budesonide, and beclomethasone, respectively (0 images), or a misc. steroid drug (1 image);
- fully carbocyclic steroids (14 images), or oxa-steroids, e.g., cardan/bufanolides, furo/spirostans, (0 images), or steroidal alkaloids/aza-steroids (0 images)
- an example tied to an important physiologic roles (4 images); an example tied to important historic/scientific role (0 images); an example tied uniquely to a structure (7 images)
- all examples of images tied redundantly to a structure type, e.g., 3 cholestanes, 3 gonanes, 2 lanosterols, etc. (10 total images), all examples of images tied uniquely to a structure type, e.g., one bile acid, one androgen, etc. (4 total images)
Key conclusions are the need to accomplish multiple pedagogic aims with single images, to reduce redundancy of some represented concepts, and to generally better represent the scope of actual steroid categories. For instance, a good single picture of lanosterol with ring lettering and numbering, adapted from the image at right below, could replace 5 current images and be more complete in its coverage of these conventions as well as show lanosterol for other purposes; a single panel for cholesterol with representations including a chair-type, with limited numbering and suitable legend, could replace most of the C-3 sterol images, well reinforce foregoing concepts, impress needed perspectives on steroid structure and function, and set-up later discussion of conformation; etc.
That is, I believe no image should appear without meeting a need of the text (generally, more than one), that ~7 composite structures can do as well as these 14, and that opening space would allow use of a few more to cover other important steroid categories/concepts (e.g., prednisolone/prednisone, to cover various currently untouched upon categories; a single secosteroid structure like vitamin D3 below presented with some numbering (ref. 1) and text relating it to 7-dehydrocholesterol; a single semiochemically important hetero/halosteroid example presented for breadth, etc.).
Bottom line, as stated elsewhere, my argument remains that content/text be designed overall, first, then figures added to illustrate key points of the the content (rather than introducing images because they are available and modestly applicable). LeProf
— Preceding unsigned comment added by 50.179.92.36 (talk) 00:12, 2 December 2013 (UTC)
References
- ^ Cite error: The named reference
Holick1995
was invoked but never defined (see the help page). - ^ A. W. Norman: Sunlight, season, skin pigmentation, vitamin D, and 25-hydroxyvitamin D: integral components of the vitamin D endocrine system. In: Am J Clin Nutr. Band 67(6), 1998, S. 1108–1110.
A potentially useful article on steroid conformations
http://onlinelibrary.wiley.com/doi/10.1002/9780470147184.ch5/summary LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 02:18, 2 December 2013 (UTC)
Some image moves, edits, and deletions...
...were made to try to address some of the observations and suggestions above. — Preceding unsigned comment added by 12.49.20.42 (talk) 01:34, 4 December 2013 (UTC)
- These are consistent with the direction I suggested, with the following further comments (and with the further caveat being that I understand the following likely requires new image creation, and so may take a while):
- General
- G1. Images showing chemical structures within the same article should use the same structural conventions, unless another pedagogic aim is addressed. Hence, here, all should be line-angle projections of the same basic appearance (scale, orientation, etc.), unless something like a chair-representation is introduced to serve a particular aim of the text. So far, so good, pretty much.
- G2. Early images should all be roughly the same scale, so as a non-specialist scans, their eye is drawn just to differences between images that makes each individual image notable. This could use immediate attention of someone who understands how to properly scale images.
- G3. When editing old or creating new images for the steroids, I would recommend that an historically strong total synthetic lab's structure representations be looked at as a guide, in particular, someone like the David A. Evans group, or the K.C. Nicolaou group, or similar. (Such groups will present the most acceptable current U.S. standards for these representations—Harvard groups, at least since the apogee of the Corey group and the emergence of ChemDraw as a standard, distribute a ChemDraw file that many if not most total synthesis groups everywhere have acquired and use as starting point for their ChemDraw schemes.) For instance, to add the CH3- for the terminal methyls is pretty much the standard, as is including the H of aldehydes, etc. This comparison will also help avoid outright errors; there are cholesterol images in the WikiMedia collection that have bold and hashed lines drawn to C-20 that are simply incorrect for their ambiguity.
- G4. In reducing the image panels to about 8, space is opened to better cover other missing steroids. One way to do this would be to combine the remaining examples into one panel with 6 or so examples, based on the carbon-count rubric (gonane, estrane, androstane, pregnane, cholane, etc,) e.g., as shown in http://www.glowm.com/resources/glowm/cd/pages/v5/v5c001.html#bas, where if a needed carbon-number example is already present on the page (like cholesterol as a cholestane), it can be pointed to. But if absent, it can appear in the panel. Hitting more than one steroid category (maximizing concept coverage by each image) is still suggested.
- Specific
- S1. The trio of images might be put in a gallery, when the scale issue is addressed. Not one of this eds. skills.
- S2. Critical sterochemical information at C-8, -9, -14, and -17 is absent on the newly introduced (Spanish?) CHOL figure, through the absence of hydrogens, and these must be added asap. (Again, even if I wanted to do this, I haven't this Wikipedia skill.)
- S2. The desire to not eliminate any substantial text already appearing is recognized and is laudable, but the legend for the Cholesterol image is long, and could benefit from editing. If CH3-'s are added as suggested in G3 above, the sentence about wedged bonds reduces to: "Wedged and hashed bonds that appear indicate groups above and below the plane of the projection, respectively." See also next point for another way to shorten.
- S3. Though it was deleted, an identically scaled image of a literature cholestane natural product (other than cholesterol) might be added back between the gonane and the cholesterol—creating a pedagogically effective gonane-cholestane-cholesterol progression—in which case the final sentence of the legend for cholesterol could be deleted.
- S4. The lanosterol substitution is helpful in its consistency with the preceding images, with the steroidogenesis scheme later, and for introducing a important common alternative methyl array. The legend of this figure (or a suitable image edit) should be used to add the accepted numbering of the methyls at C-4 and C-14 (see my German image above). If there is a reason for still wanting a stick representation, one can perhaps go in and cover another steroid example—a fungal or bacterial, or an unusual derivative like brassinolide (with explanation of what further the choice of the stick representation is meant to convey)?
- S5. Is there a better therapeutic example to use than medrogestone? Dexamethasone is already mentioned in the text, and the most common inhaled and injected are listed above in my counting Talk section.
- Cheers. LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 03:46, 4 December 2013 (UTC)
As long as attention is being paid to lead... [1]
... the mistake of calling cholesterol a "fat" can be changed, most easily to "lipid", and pointers can be added to the images in the gallery that are finally decided upon. LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 03:47, 4 December 2013 (UTC)
Following text removed, for later replacement at appropriate position...
The following was placed in the Partial and total (chemical) synthesis section, after editing the section name.
This material is not what this section was designed to hold—it is a section for chemical synthesis, and not microbial transformations.
Discussions with the article's principle editors can determine what section this should appear in, or if a new section is needed.
" Phytosterols, especially a mixture of soybean phytosterols, as starting materials can be converted into two kinds of steroid hormone intermediates through microbial transformation. Microbial catabolism of phytosterol sidechains yields either C-19 steroids, a precursor to most steroid hormones including sex hormones, or C-22 steroids, a precursor to adrenocortical hormones.
The chemical conversion of sapogenins to steroids — Marker degradation combined with Mexican barbasco trade — is a long established alternative to microbial transformation of phytosterols to steroids. It is however unsustainable since huge tubers of plants growing in the wild were harvested.[1][2] "
LeProf.— Preceding unsigned comment added by 50.179.92.36 (talk) 05:55, 4 December 2013 (UTC)
References
- ^ Conner AH, Nagaoka M, Rowe JW, Perlman D (1976). "Microbial conversion of tall oil sterols to C19 steroids" (PDF). Appl. Environ. Microbiol. 32 (2): 310–1. PMC 170056. PMID 987752.
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ignored (help)CS1 maint: multiple names: authors list (link) - ^ Wang F-Q, Yao K, Wei D-Z. "From Soybean Phytosterols to Steroid Hormones, Soybean and Health". In El-Shemy H (ed.). Soybean and Health. InTech. doi:10.5772/18808. ISBN 978-953-307-535-8.
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WAIT AND SEE THE TALK...
...BEFORE YOU IMMEDIATELY REVERT AN EDIT MADE BY AN ESTABLISHED AND CREDENTIALED EDITOR. LEPROF — Preceding unsigned comment added by 50.179.92.36 (talk) 05:59, 4 December 2013 (UTC)
- All you have to do is explain what you are up to. When you simply remove text without explanation, that is a problem.I am One of Many (talk) 06:01, 4 December 2013 (UTC)
- Read the section immediately above: I did explain, also immediately. You acted FAR too quickly! LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 06:05, 4 December 2013 (UTC)
Three "citation needed" tags added...
...Regulation section, to three clearly factual sentences derived from at least one (maybe more) research literature sources. These are clearly not introductory, segue, or common knowledge statements. Let's not begin the nefarious process of introducing un-sourced, and so plagiarised (per wikipedia definition, since ideas must also be sourced) material into this important and already struggling article. If time can be taken to introduce the prose, it can be taken to introduce at least a draft form of the citation from which the prose was derived. LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 06:12, 4 December 2013 (UTC)
- If you know anything about steroids, why don't you add the missing sources? Why not improve the article? I don't understand what exactly you intend to do. I am One of Many (talk) 06:38, 4 December 2013 (UTC)
- It is not the responsibility of other editors to do forensic referencing, to try to guess at where factual, scientific information was gleaned by an earlier sloppy contributor. This practice you suggest is both inefficient, and fraught with deeper accuracy problems related to the guess-work nature of any post hoc citation effort. No, this is a chemistry Wikipedia article area, with clear standards related to attribution of factual, citation-derived information. Yes, I know about steroids. And I have contributed at considerable scholarly material and perspective here (see above). But no, I am not taking it on myself to determine from whence another's facts and prose are cribbed, and I strongly discourage others from this as well. Bad scientific form, bad idea, all around. LeProf. — Preceding unsigned comment added by 50.179.92.36 (talk) 06:49, 4 December 2013 (UTC)
Regular contributing editors, I appeal again...
...that this article be reduced to a minimal profile, with sections that are empty removed, and any sections with un-cited text also transferred to Talk. Otherwise this article has the appearance of a Sandbox, and as long as it does, it will invite the sort of scratching and burying that sandboxes do—evidence recent "deposits" left of late (either misplaced, or seemingly properly placed but without a shred of scholarly attribution). Please, please, please, take firm action before this IMPORTANT article goes from ... to worse. LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 06:33, 4 December 2013 (UTC)
- This simply is not how Wikipedia works.
without a shred of scholarly attribution
– In Wikipedia, the only attribution that maters is WP:RS. Given the subject mater of this section WP:SCIRS applies. Both PMID 987752 and 978-953-307-535-8 would appear to qualify as reliable sources, although if would be preferable if the former were a secondary and more recent. I would also remind you of WP:NORUSH. Rome was not built in a day. Boghog (talk) 11:44, 4 December 2013 (UTC)
- Sections, paragraphs without scholarly attribution, see below. LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 16:54, 5 December 2013 (UTC)
- Please clarify what you mean by "without scholarly attribution". Do you mean the selection of the source was not scholarly (i.e., the best sources was not used)? If so, please replace the original sources with better sources and restore the reverted text. Thanks. Boghog (talk) 12:28, 4 December 2013 (UTC)
- There are issues other than reliability that come into play, to determine if bits of text should be added, or Pubmed-mining and addition of every new tidbit would be acceptable practice. But this is an arguement for another time, when it actually applies.
- This "Regular contributing editors I appeal..." new section was not created in relation to the issue with the microbial transformations text that I redacted. The issue there was not reliable sourcing, but of the added text not being germane to the heading where it was placed (and thereafter, to an overzealous outside editor reverting the redacts without checking Talk, and so making false drive-by claims). A microbial/enzyme-mediated transformation could be conceivably be used in a total synthesis, but here the papers are simply not about compound synthesis.
- I fully expect you to re-introduce the microbial transformation texts—and of course, as you do, to bring them much closer to understandable, high quality prose—wherever you wish them to go. But please, when reintroducing, don't do so in Partial and total chemical synthesis, or your outline becomes meaningless. And if you read the edit log, it's clear the contributor knew that his text didn't fit there—s/he had to edit the Section title to make the Section title properly reflect the new content.
- The only way that this appeal relates to the microbial transform redact: I still oppose empty sections in articles, for the very reason that people may begin to populate them without adequate understanding of the subject. If you want to leave the sections in, add a paragraph to each, so those without background understand what is intended. And note, in the appeal I said "calling-all-cars (editors)" and you are my one respondent. You understand why, when you revert me while I am yet working, I say, its yours? 2 – 1 = 1. Cheers. LeProf. — Preceding unsigned comment added by 50.179.92.36 (talk) 16:53, 5 December 2013 (UTC)
Partial and Total Chemical Synthesis Section redefined through reversions: The inexplicable visits of I am One of Many and Sminthopsis84
I'd like to call attention to the fact that an editor has again inserted two bits of text unrelated to a subject heading, then editing the heading title so that the text better would fit it, both without any explanation I can find here.
I removed the misplaced text earlier, placing it in Talk, and explaining why I removed it. Please see Talk Section above, "Following text removed, for later replacement at appropriate position...". (The explanation was 60 words, short enough for even for you, Bohog, to read without complaint of my being tiring!)
Before I could finish the original redaction and Talk entry, I am One of Many reverted my edit—which, with its Talk explanation, were brief, polite, and conservative, being aimed at keeping the original Section going in the direction of the editor that had placed its heading.
I replied to I am One of Many everywhere—his talk, here, etc.—explaining that he had acted too quickly, and pointing to the finished Talk entry (title, see above) to explain why I had redacted the text and moved it to Talk. As a result, I am One of Many ceased reverting.
Now, I return to the article to find that another rare-to-visit editor, Sminthopsis84, has again reverted the redaction, re-changing the Section heading, and returning the misplaced, microbial transformation text to the Section intended to contain, as its original title stated, information on steroid partial and total synthesis. STRIKINGLY, Sminthopsis84's reversion was done with no explanation that I can find, here in Talk.
This finishes it here for me here. This is article is a Wild West of wasted time and effort. I leave it to Bohog to return things to the way he intended when he introduced the section headings. He can then perhaps persuade User:I am One of Many or Sminthopsis84 to write the synthetic organic content that was intended to go there.
Or not. I'll not discuss or take action on this again. Three strikes and I'm out. — Preceding unsigned comment added by 50.179.92.36 (talk) 20:30, 6 December 2013 (UTC)
Regarding earlier WP:DRIVEBYTAGGING assertion
Finally, a kind senior Wiki editor explained to me what you meant, earlier, by "WP:DRIVEBYTAGGING"—and our conclusion is that it simply does not apply to the situations at hand. A drive-by, here, refers to significant edits unexplained in Talk. If a second editor reverts without waiting long enough to see entries in Talk, or reverts despite entries in Talk, to argue that the initial redactive edit was a drive-by is incorrect (from what I am told). The reasoning given for the redaction may be rejected, but it is not WP:DRIVEBYTAGGING. So, this seemingly intended pejorative should be substituted by a better WP reference, to explain why all my earlier citation-needed tags were removed. Perhaps one that speaks to who owns/controls content? ; ]
As for the term, I won't use it again. It's a serious, ill-borne allusion. Like other offensive cultural terms, it should have been avoided in wiki parlance. LeProf
- According to Drive by tagging
it's useful to leave a short note on the talk page describing the issue
. Your notes above fall in the category of WP:TL;DR No explanation is unacceptable. Likewise, excessively long explanations are also problematic. Boghog (talk) 22:44, 5 December 2013 (UTC)
- They weren't to start with, and they will not be from now on. The reversion of the synthesis section is the last straw. Enjoy. — Preceding unsigned comment added by 50.179.92.36 (talk) 07:50, 6 December 2013 (UTC)
- DRIVEBYTAGGING also refers to editors tag articles and never return to help with improving the content. I have a pet peeve against editors who complain about articles, but do little or no work to actually improve them. You past editing (see for example Talk:Hit to lead) suggests such a tendency. You have provided a lot of useful suggestions above. It is now time for you to act on those suggestions. Boghog (talk) 08:31, 6 December 2013 (UTC)
- Sorry mate. I read what I could find on this WP you like to use, and it seems you are redefining a WP to address your pet peeve (rather than following the text of the WP, prima facie for what it says). Per the WP, Sminthopsis84's recent edits here were D...B...; my efforts simply were not. And note, mate, you wield WPs far too frequently and far too self-servingly. Physician, heal thyself. See your User:Talk for the rest of my final reply to your "tendencies" analysis, accusation of suggesting rather than composing, to your accurate but largely unreferenced (and so draft, and encyclopedically unready) Hit to lead edits. I'm done here, see below and Talk. Cheers/Bye LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 21:48, 6 December 2013 (UTC)
Sections, paragraphs without scholarly attribution...
...referred to above, include:
- Nomenclature [essentially all of it; only a Pubchem link appears, no refs. to any textbook or review or reference article on the subject]
- Taxonomical/functional [ditto, except not event the Pubchem link]
- Structural [ditto, no general ref. to concept of structure-based categorization; single non-chem ref., only to gonane nomenclature]
- Biological significance [two thirds of the sparse information is without citation]
- Pharmacological actions [ditto, except all is without]
- Biosynthesis and metabolism [ditto, except all is without]
- Mevalonate pathway — can skip, huzzah
- Steroidogenesis [about three quarters of the essentially outlined information is without citation]
- Regulation [all is without,
- AND IT WAS THIS JARGON/DATA RICH TEXT THAT PROMPTED THE "WITHOUT A SHRED OF SCHOLARLY
- ATTRIBUTION" STATEMENT, THOUGH IT LIKEWISE APPLIES TO MANY OTHER BULLETS ]
- Alternate pathways, Metabolism — can skip, Oh frabjous day! Callooh! Callay!
- Partial and total chemical synthesis...
- Determination of structure and methods of analysis...
- Methods of isolation... [empty, empty, and empty, but if filled according to the foregoing pattern, what do you expect to see? ]
This I think does indeed substantiate the conclusion, that for the largest part (lit., in most of its parts), this article is without a shred of scholarly attribution. It may be correct, but it is of the "trust us, it's right" school of authoring, and it is not WP policy to let it stand.
Bottom line, I'd posit that Wikipedia works in whatever way the local majority or most aggressive and determined editor finds able to act in the context of other editors. Note, in various other venues I have removed unreferenced sections without attribution, without incident (indeed receiving thanks). On the other hand, in the Species article, the final cribbed, essentially citation-less 1600 word section has remained for 4 years (despite my attempts to shame its owner there into action). Not going to fight with you guys about it, but the practice of text-without-citation-world-without-end is a load of horse **** (hair).
Since I am ultimately submissive in these situations (noisy, but ultimately submissive), you can act on this any way you please. But be clear: if unreferenced "may be removed", per the tag warning—for your article, when may it be? (It's already clear that my timelines can't apply, here, since tags giving starting dates were removed.) So my conclusion is that I can remove offending citation-free text (am technically capable) ... but here I may not, whatever the relevant WP's might say. Cheers, LeProf — Preceding unsigned comment added by 50.179.92.36 (talk) 17:49, 5 December 2013 (UTC)
- No answer? — Preceding unsigned comment added by 50.179.92.36 (talk) 09:43, 6 December 2013 (UTC)
- Instead of simply deleting material, how about replacing it with higher quality material supported by reliable sources? Boghog (talk) 15:56, 6 December 2013 (UTC)
- Were I to do that, you would allow the redaction and replacement to stand? No, because you have reverted, or supported reversion, of everything I have ever written, anywhere, where you are also an editorial presence. Article is yours, until the community wises up and takes it back. Leprof 7272 (talk) 01:46, 11 December 2013 (UTC)
Per "WP:PROVEIT": Responsibility for referencing lies with original or deletion-reverting editor, not with later editors making deletions; if later editors know a suitable source they may provide it, but they are not obligated to do so. Statements above promoting the original contributor's return to add references and/or to (lack-of-referencing driven) deletion-reverting editors not doing so without providing such references is consistent with this interpretation of the WP. Quoting: "Any material lacking a reliable source directly supporting it may be removed and should not be replaced without an inline citation to a reliable source. … Sometimes editors will disagree on whether material is verifiable. The burden of identifying a reliable source lies with the editor who adds or restores material, and is satisfied by providing any reliable source that directly supports the material." [italics added] LeProf
Error in biochemistry nomenclature corrected.
Fats are triglycerides (triacylgycerol), which cholesterol is not. Cholesterol is a dietary lipid. — Preceding unsigned comment added by 75.146.23.101 (talk) 05:20, 22 December 2013 (UTC)