Talk:Carotenoid

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Structure[edit]

Shouldn't there be a picture with the structure of the carotenoids up there? 71.245.246.18 02:17, 5 April 2006 (UTC)

600 known carotenoids? I can't find that many on this site. Twilight Realm 01:20, 6 January 2006 (UTC)
well, it's a good point. perhaps just one of the carotene structures, since they are often the backbone? Alternatively, something that shows the numbering used in chemical nomenclature would be suuuuper helpful to this article! here's something i found on google images but we would need to look into its source and whether it falls under a fair use license, or if we can obtain one... http://www.chem.qmul.ac.uk/iupac/carot/cargif/c2.gif MM (talk) 12:28, 15 July 2016 (UTC)

Redshift[edit]

Won't a red shift in absorbtion make the apparent color more blue? I don't see how absorbing more red will make the molecule appear more red. Brianf711 19:04, 20 February 2006 (UTC)

Template help[edit]

If anyone has time, the {{Carotenoids}} template would really benefit from your expertise. Thanks! :) Willow 19:09, 27 January 2007 (UTC)

Synthesis in Corpus Luteum[edit]

It's not completely true that carotenoids cannot be synthesized in animals. Beta-carotene can be synthesized from acetyl-CoA and mevalonate in the corpus luteum (Gawienowski AM. Integration of the Metabolic Pathways of Steroids, Carotenoids and Retinoids. Critical Reviews in Biochemistry and Molecular Biology. 34(6):405-410 (1999)). Icek 14:53, 24 July 2007 (UTC)

Sorry, but although there exists a 1968 paper claiming to detect beta-carotene synthesis in in vitro bovine corpus luteum tissue slices, from radiolabeled acetate, careful attempts to replicate this have failed: see [1]. Moreover, there is independent reason not to believe it, since what would keep such beta carotene from difussing out of the corpus luteum, being metabolized in various tissues by dioxygenase, and allowing cows to make their own vitamin A (meaning that they'd have no vitamin A requirement?). Mammals can make squalene and there are strong evolutionary pressures for them to go on an make vitamin A (particularly vegetarian animals) but so far as we can tell, none of them can do it. SBHarris 22:36, 30 April 2010 (UTC)

Lead[edit]

I've added that carotenoids are also found in chloroplasts which has made the lead a little bit tricky to read. Shouldn't there be some mention of B-carotene being in animals too? The above post also seems to fit with this. Smartse (talk) 16:41, 27 May 2009 (UTC)

A study link for the animal link would be nice. prokaryotes (talk) 04:35, 27 January 2016 (UTC)

Synthesis in aphids[edit]

I added that carotenoids are synthesized by Aphids, as per Science 328 (5978), 624. DOI: 10.1126/science.1187113 idoerg

You should have added the reference, too, but I did it for you. Nice addition, and a very cool finding for science. And people worry about genetic engineering for animals in the wild. I suppose these Franken-aphids will now be as scary to the Greenpeace as Golden rice. SBHarris 17:19, 30 April 2010 (UTC)

I actually added the reference, but further down in the text body (ref #10) so now we have refs #1 and #10 to the Moran paper which are identical. Any way to consolidate that? I like it that your added reference is on top, but by wikipedia-foo is not strong enough to put the same reference tag in the text body (scroll down).

Done. Have a nice day.—Tetracube (talk) 19:57, 30 April 2010 (UTC)
Thanks, Tetracube! SBHarris 22:01, 30 April 2010 (UTC)

Distribution across tree of life[edit]

There should probably be a section which discusses which major evolutionary groups of organisms across the tree of life synthesize carotenoids (and which kinds, roughly). For instance, are there any groups of organisms which completely lack carotenoids? (nothing turns up in my head!) and what was their evolution? it's been hypothesized they originated in the Archaea, contributing membranse structure. And some groups of organisms base their carotenoids off of distinct backbones (eg alpha vs beta vs gamma carotene). This is something I'd like to do eventually but don't have time so I'm putting it up here in case someone else is up for it. MM (talk) 12:21, 15 July 2016 (UTC)

Black tea[edit]

Some studies on carotenoids and their degradation in black tea manufacture may be of interest - Says violaxanthine and neoxanthine are important. Rod57 (talk) 03:12, 23 September 2010 (UTC)

Dietary carotenoids[edit]

Lutein and Zeaxanthin; An Introduction to the Chemistry of Dietary Carotenoids looks interesting - nice images, and diagram ordering by anti-oxidant activity. Rod57 (talk) 23:52, 7 December 2010 (UTC)

An excellent article. Too bad we can't just copy the illustrations! As for "anti-oxidant" activity, this article makes one of many points, which is that there's no such "thing" on a simple scale. The xanthophyll carotenoids (astaxanthin, zeaxanthin, etc) are far better at de-quenching singlet oxygen, which is why they are made in such abundance by plants. While the carotene carotenoids (lycopene, beta-carotene, etc) make better sacrificial free-radical targets. These things have very different lives in the excited state, also, and this is influenced strongly by their hydrophobicity, which in turn is a function of their oxygen content also. Probably it takes all kinds to do a lot of things, healthwise. The people who advocate a wide spectrum of whole-food fruits and vegetables are not so dumb. Particularly with the recent disasters in attempts at supplementing beta carotene to smokers and others at cancer risk. SBHarris 18:43, 15 September 2011 (UTC)

synthesis[edit]

Hello I miss informations about the biosynthesis of carotenoids in plants: originating from tetraterpenes + Desaturases which insert more double bindings. Source: [1]

References

  1. ^ "Taschenlehrbuch Botanik" Thieme; Main author: Katharina Munk

-- 95.91.207.3 (talk) 20:28, 4 January 2016 (UTC)

Cancer protection[edit]

Jytdog removed the addtion Mixed carotenes from food sources can protect against cancer, cataracts, osteoarthritis, and heart disease., with summary "no. do not cherrypick this way" Jytdog should explain why he thinks that eating your veggies argument should not be backed up by science. prokaryotes (talk) 03:36, 27 January 2016 (UTC)

Yes you are very aware of the cochrane review that is more recent that is in the beta-carotene article, that says the opposite of what you wrote here. You edited that at 3:17 and seconds later wrote the opposite here, based on an older and more poor source. That is the definition of cherry-picking. Jytdog (talk) 04:04, 27 January 2016 (UTC)
No, i am not aware that this review you mention covers above part, the other edit was only about cancer protection due to less oxidaditve stress, and a link. Your conclusion is false.
Link the study, not sure which review you mean, unless it is the one covering cataracts.prokaryotes (talk) 04:14, 27 January 2016 (UTC)
  • Second revert Still no valid reason by you, did you read my edit summary? The cataracts study is about supplements with vitamins and beta carotene and only covers cataracts. Your edits are disruptive, you follow my edits, and you do not provide a reason for your reverts. prokaryotes (talk) 04:41, 27 January 2016 (UTC)
second edit warring insertion prior to finishing discussion you are introducing a poor source (tertirary) that contradicts more recent and better (secondary) sources here and in the beta-carotene article. please stop. Jytdog (talk) 04:53, 27 January 2016 (UTC)
DocJames noted about the same source It is a decent source. I ask you now again to provide a source, which covers the content.prokaryotes (talk) 05:02, 27 January 2016 (UTC)
it is "decent" but not as good as more recent reviews, which are better. we don't use poorer and older sources to contradict more recent and better ones. Please read WP:MEDRS. and more than anything we read the article before we add stuff. Jytdog (talk) 05:05, 27 January 2016 (UTC)
There is no contradiction, since the newer study you refer to, is about "beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium". And this study does not cover cancer at all, or it does not cover health benefits of carotenoids at all. What you did is you blanked parts of the content. prokaryotes (talk) 05:11, 27 January 2016 (UTC)
the content you wanted to add is not about supplements (which the source you just cited is about) but rather about carotenes from food. please read the next sentence and its sources. Jytdog (talk) 05:16, 27 January 2016 (UTC)
i just updated the section with the most recent secondary sources. the 2007 tertiary source is even less relevant now. it is helpful to focus on improving the article. Jytdog (talk) 06:02, 27 January 2016 (UTC)
Good however, the study we discuss in this section here is about carotenoid from food sources, and the source also states "Food rich in carotenoids (i.e., colorful vegetables and fruits) are generally considered more beneficial than isolated beta-carotene supplements. Furthermore, products containing only purified beta-carotene, especially of synthetic origin, may actually increase risk for or counter therapeutic measures." Hence why you cannot use a supplement review to replace a food based study or review.prokaryotes (talk) 06:08, 27 January 2016 (UTC)
i have not been talking about supplements for our last few exchanges, but rather about the epidemiological studies about food consumption. also, the book is older and tertiary. please read the current sources. thanks. Jytdog (talk) 06:22, 27 January 2016 (UTC)
i'll add that picking a line or two out of an older, poorer source is a suboptimal way to build an article. please read the current sources and build content expressing the mainstream views in them. Thanks. Jytdog (talk) 06:25, 27 January 2016 (UTC)
Very strange that you now add sources which support the basic premise we discuss. Just, you just added these sources. Thats a very weird way of editing. This seems good, will have to give this some thought. Probably have to reflect that in the bottom RFC, which was based on your deletion spree. The next time you do this you could briefly mention that you will update the article further, and maybe schedule it so it doesn't overlap with my edits. You could have saved us both a lot of typing.prokaryotes (talk) 06:29, 27 January 2016 (UTC)

RFC on recent content changes (Deleted content)[edit]

On hold.

Recently editor Jytdog removed an addition about protectve properties of carotenoide (see above section), without providing convincing evidence. After that he begun to remove large parts of long standing article content. For instance the part about Carotenoid properties begins now with a study about mortality of random trials with "beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium" -- Recent content removal by editor Jytdog prokaryotes (talk) 05:19, 27 January 2016 (UTC)

Question, should we re-add the deleted content (revert the sweeping changes), concerning these edits -  Recent content (also see article history). Vote below with (Support/Oppose).

Vote[edit]

Support Per above. prokaryotes (talk) 05:32, 27 January 2016 (UTC)

Comments[edit]

Premature; we have hardly begun discussing nor have others who watch this page had a chance to comment yet. Jytdog (talk) 05:16, 27 January 2016 (UTC)
and misrepresents the discussion which is just above. procaryotes you are moving too fast and not even dealing with the content that was already in the article when you added this. so disruptive. Jytdog (talk) 05:19, 27 January 2016 (UTC)
I have asked you 3 times to provide a source, you provided none. My hint about the discrepancy is ignored. You do not follow Wikipedia standards, when removing well sourced content. Instead of tagging for citation needed you delete. Anyway the interaction seems to go nowhere, hence why it is time to get some fresh input.prokaryotes (talk) 05:24, 27 January 2016 (UTC)
I have answered every time. you are moving too fast. Jytdog (talk) 06:23, 27 January 2016 (UTC)
and i don't see the point in the RfC as the question is no longer relevant. many better and newer sources are now incorporated in the article.
Removed the RFC, need to check the page, which essentially readds content similar in scope of what has been removed. prokaryotes (talk) 06:31, 27 January 2016 (UTC)
With the new sources it appears we don't need the RFC. (Only checked the diet stuff) prokaryotes (talk) 21:38, 27 January 2016 (UTC)