Treating with Vitamin C
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Peter Eichler
New member
I've skimmed through a couple of these threads here and on Reef2Reef. I've seen vitamin C dosing come and go as a fad in this hobby at least a few times so I've resisted posting.
The "results" I see in most of these posts point to the ascorbic acid being little more than a carbon source. I take a look at the before and after shot of the blue zoanthids that Jenny posted and in the before shot I see zoanthids in a tank that has high nutrients and algae taking over the polyps, and the second shot I see a healthier lower nutrient tank, probably not some great benefit from the vitamin C itself. Some experiencing better colors, others not, cloudy water, slime buildup as a result of bacterial blooms, nitrates and phospahtes comeing down, smellier and more skimmate being produced all are the same exact things you'll find in one of the various sugar/vodka dosing threads. I would also speculate that some of those experiencing problems from dosing vitamin C already had pretty low nutrient levels.
I slacked a little on my maintenance over the winter and had a couple colonies that looked somewhat similar to the blue colony, thought not as bad. A few good size water changes and a little more aggressive skimming and over the course of 6 weeks all of the sad looking colonies have improved greatly. I don't doubt that dosing of a carbon source could have had similar effects, but also running the risk of the drawbacks assosciated with such dosing. Also, during that time I could have been dosing a bottle of magic water and falsely concluded that my magic water is why my corals look healtier.
I've seen mention of vitamin C boosting the immune sytem in a coral/zoanthid. I find that very difficult to believe. Without going into a long explanation the simplest explanation is corals do not have immune systems like humans and other mammals do.
Many things to consider when it comes to ascorbic acid. It's highly unstable when exposed to light, oxygen, and heat... In fact it's an exygen scavenger which is something to consider when dosing high levels in a marine aquarium.
If you are dosing or want to dose vitamin C, great. If you really think it is improving you tank and coral health I congratulate and am happy for you and am not trying to convince anytone to stop. But understand this, the results thus far have been anecdotal at best and I've seen nothing scientific to suggest that such high levels of vitamin C would benefit corals in any way. The benefit of reducing nutrients by adding a carbon source can much more easily explain the benefits some of you are seeing, and there is some sciene to back that up. Please don't post an advertisement errr "article" from Thiel as being scientific because you'll just end up with a long rant from me about how wrong he was about many things and what a crook he was.
In short, to me this all seems like a more expensive less efficient way of dosing a carbon source, but with more possible drawbacks. One thing is for sure though, you won't have any problems with fish or inverts getting scurvy :lol:
The "results" I see in most of these posts point to the ascorbic acid being little more than a carbon source. I take a look at the before and after shot of the blue zoanthids that Jenny posted and in the before shot I see zoanthids in a tank that has high nutrients and algae taking over the polyps, and the second shot I see a healthier lower nutrient tank, probably not some great benefit from the vitamin C itself. Some experiencing better colors, others not, cloudy water, slime buildup as a result of bacterial blooms, nitrates and phospahtes comeing down, smellier and more skimmate being produced all are the same exact things you'll find in one of the various sugar/vodka dosing threads. I would also speculate that some of those experiencing problems from dosing vitamin C already had pretty low nutrient levels.
I slacked a little on my maintenance over the winter and had a couple colonies that looked somewhat similar to the blue colony, thought not as bad. A few good size water changes and a little more aggressive skimming and over the course of 6 weeks all of the sad looking colonies have improved greatly. I don't doubt that dosing of a carbon source could have had similar effects, but also running the risk of the drawbacks assosciated with such dosing. Also, during that time I could have been dosing a bottle of magic water and falsely concluded that my magic water is why my corals look healtier.
I've seen mention of vitamin C boosting the immune sytem in a coral/zoanthid. I find that very difficult to believe. Without going into a long explanation the simplest explanation is corals do not have immune systems like humans and other mammals do.
Many things to consider when it comes to ascorbic acid. It's highly unstable when exposed to light, oxygen, and heat... In fact it's an exygen scavenger which is something to consider when dosing high levels in a marine aquarium.
If you are dosing or want to dose vitamin C, great. If you really think it is improving you tank and coral health I congratulate and am happy for you and am not trying to convince anytone to stop. But understand this, the results thus far have been anecdotal at best and I've seen nothing scientific to suggest that such high levels of vitamin C would benefit corals in any way. The benefit of reducing nutrients by adding a carbon source can much more easily explain the benefits some of you are seeing, and there is some sciene to back that up. Please don't post an advertisement errr "article" from Thiel as being scientific because you'll just end up with a long rant from me about how wrong he was about many things and what a crook he was.
In short, to me this all seems like a more expensive less efficient way of dosing a carbon source, but with more possible drawbacks. One thing is for sure though, you won't have any problems with fish or inverts getting scurvy :lol:
Pufferpunk
New member
We actually had to rethink Thiel's chart & make one of our own.
Jeff
Premium Member
I ran vitamin c on my main display for months following Puffys advise and had great sucess which included massive growth and incredibly colorful corals. I always suspected the ascorbic acid was being used as a carbon source and not as a "vitamin" so when I discontinued use when I started using Prodibio (ultra low nutrient, carbon dosing system) which is the same type of system as ZEOvit and Ultralith, I started seeing some softies start to diminish and go back to slower growth.
I have been using the ultra low nutrient system for exactly two months now and my reef has had massive growth/coloring up of sps and lps.
My point here is this: The vitamin C prgram that Puffy uses is a huge sucess and some of what Peter Eichler says I have found to be true. He may not have stated it in the nicest or most scientific way
p) but his theory may be somewhat true. Whatever the vitamin c does works, period. Its a really cheap way of improving your tank. We still dont really know how it works but it does.
I have been over to Puffys house many times and seen her sucesses with vitamin c on her mixed reef and the results speak for themselves.
I have been using the ultra low nutrient system for exactly two months now and my reef has had massive growth/coloring up of sps and lps.
My point here is this: The vitamin C prgram that Puffy uses is a huge sucess and some of what Peter Eichler says I have found to be true. He may not have stated it in the nicest or most scientific way
p) but his theory may be somewhat true. Whatever the vitamin c does works, period. Its a really cheap way of improving your tank. We still dont really know how it works but it does. I have been over to Puffys house many times and seen her sucesses with vitamin c on her mixed reef and the results speak for themselves.
Pufferpunk
New member
Well put, Jeff! I spoke to many of the speakers at IMAC this weekend, including Adam Cesnales, Steven Pro, Scott Fellman & more. They all came to see my tanks & loved them! They also all agreed on the carbon source & said if it ain't broke don't change anything.
also helped me to discover that a rabbitfish will eat the horrible red turf algae in my tank, so I ordered an orange spot from my LFS.
also helped me to discover that a rabbitfish will eat the horrible red turf algae in my tank, so I ordered an orange spot from my LFS.
OCEAN SIZE
BACK REEFIN'
I'm personally willing to carefully use pure, high-grade C if it provides benefit (though I'm going to proceed very slowly if I go this route).
Would it stand to reason that Vitamin C as a steady carbon source would provide advantage to particular bacteria, leading to monoculture?
Would it therefore be better to combine Vitamin C with methanol, sugar, vinegar, and/or vodka in that case?
I know, it sounds like a coctail recipe, and I'm not advocating for sharing Absynthe with our animals while we drink... I'm asking a legit question...
Pufferpunk
New member
As I was told by Adam Cesnales this weekend: "If it ain't broke..." I find adding the VC is good enough for my corals/fish & my nitrate in all 3 tanks is basicaly non-existant because of what it does for the biological bacteria.
SW_nOOb_SC
New member
So adding VC would be a benefit even if you didn't have polyps starting to look bad?
Pufferpunk
New member
Absolutely! In addition to the nitrate decline, my LPS & leathers seem to respond the biggest with the addition of VC, 2nd to the zoanthids.
Jeff
Premium Member
<a href=showthread.php?s=&postid=12663138#post12663138 target=_blank>Originally posted</a> by OCEAN SIZE
Would it stand to reason that Vitamin C as a steady carbon source would provide advantage to particular bacteria, leading to monoculture?
Would it therefore be better to combine Vitamin C with methanol, sugar, vinegar, and/or vodka in that case?
I know, it sounds like a coctail recipe, and I'm not advocating for sharing Absynthe with our animals while we drink... I'm asking a legit question...
Legit question? Incredible question that I also have been wondering about. As stated above, I have had great sucess with vitamin c and also great sucess with an ultra low nutient system. I am wondering if I can combine the two methods without a huge algae bloom or worse. I have been so happy with my results with Prodibio that I am scared to start up the vitamin c again. I think it may prove to be an unstable growth medium for bacteria. I guess I could start really low and ramp up gradually but as with everything else in this hobby I would rather somebody else took the plunge and used 10+ ppm vitamin c with Prodibio, ZEO, or Ultralith before me lol.
toaster77
New member
While what Peter Eichler wrote stating that the main benefits of dosing Vitamin C are simply due to ascorbate being a carbon source like vodka, sugar, etc., might be correct, don't completely exclude the possibility that ascorbate is functioning as an antioxidant that might stimulate photosynthetic output or reduce phototoxicity. there are numerous reports in the literature examining roles of ascorbate in photoprotection. also i believe there is really some truth to all the stuff you hear about antioxidants being good for you - in the literature there are such reports that antioxidants like ascorbate can promote cell survival and proliferation.
Skeptic_07
New member
In response to Jeffs post, i think we should look at what these substances are and what they do on a chemical level before diving into speculation and anecdotal evidence.
Sugar, vinegar, alcohol and vitamin C are all organic compounds. That is they are comprised of hydrogen, carbon and oxygen.
Sugar, sucrose or table sugar for our purposes, systematic name is ¥á-D-glucopyranosyl- (1¡ê2)-¥â-D-fructofuranoside (ending in "oside", because it's not a reducing sugar). It is best known for its role in human nutrition and is formed by plants but not by other organisms such as animals. Water breaks down sucrose by hydrolysis, however the process is so gradual that it could sit in solution for years with negligible change. Carbohydrates (sugars) and sugar alcohols are an important class of compounds containing multiple alcohol functional groups. For example, sucrose (common sugar) contains eight hydroxyl groups per molecule.
Vinegar, alcohol and vitmain C are organic acids. "An organic acid is an organic compound with acidic properties." "Upon passive diffusion of organic acids into the bacteria, where the pH is near of above neutrality, the acids will dissociate and lower the bacteria internal pH, leading to situations that will impair or stop the growth of bacteria. On the other hand, the anionic part of the organic acids that cannot escape the bacteria in its dissociated form will accumulate within the bacteria and disrupt many metabolic functions and lead to osmotic pressure increase, incompatible with the survival of the bacteria."
Vinegar is made up of water and acetic acid. Acetic acid is one of the simplest carboxylic acids. "The acetyl group, derived from acetic acid, is fundamental to the biochemistry of virtually all forms of life. When bound to coenzyme A it is central to the metabolism of carbohydrates and fats. However, the concentration of free acetic acid in cells is kept at a low level to avoid disrupting the control of the pH of the cell contents." "Acetic acid is also a component of the vaginal lubrication of humans and other primates, where it appears to serve as a mild antibacterial agent."
There are many different chemical forms of alcohol. In chemistry, an alcohol is any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group. Alcohols "are generally slightly weaker acids than water, but they are still able to react with strong bases such as sodium hydride or reactive metals such as sodium." The alcohol in vodka is ethanol. The addition of even a few percent of ethanol to water sharply reduces the surface tension of water. Ethanol can be oxidized to acetaldehyde, and further oxidized to acetic acid.
Vitamin C or L-ascorbate is also known as ascorbic acid. "L-ascorbate is a weak sugar acid structurally related to glucose which naturally occurs either attached to a hydrogen ion, forming ascorbic acid, or to a metal ion, forming a mineral ascorbate." Vitamin C is also a strong reducing agent. "A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction." The most important of these in out application is "denitrification, nitrate reduces to nitrogen in the presence of an acid." "Biological energy is frequently stored and released by means of redox reactions." Cellular respiration and photosynthesis involve a series of redox reactions.
Lets try to draw our conclusions from what we know to be true and not from speculation and anecdotal evidence.
Works cited: Wikipedia.
Amazing how that site can turn anyone into an expert.
Also, isn't it amazing what you can accomplish on a lunch break?
Sugar, vinegar, alcohol and vitamin C are all organic compounds. That is they are comprised of hydrogen, carbon and oxygen.
Sugar, sucrose or table sugar for our purposes, systematic name is ¥á-D-glucopyranosyl- (1¡ê2)-¥â-D-fructofuranoside (ending in "oside", because it's not a reducing sugar). It is best known for its role in human nutrition and is formed by plants but not by other organisms such as animals. Water breaks down sucrose by hydrolysis, however the process is so gradual that it could sit in solution for years with negligible change. Carbohydrates (sugars) and sugar alcohols are an important class of compounds containing multiple alcohol functional groups. For example, sucrose (common sugar) contains eight hydroxyl groups per molecule.
Vinegar, alcohol and vitmain C are organic acids. "An organic acid is an organic compound with acidic properties." "Upon passive diffusion of organic acids into the bacteria, where the pH is near of above neutrality, the acids will dissociate and lower the bacteria internal pH, leading to situations that will impair or stop the growth of bacteria. On the other hand, the anionic part of the organic acids that cannot escape the bacteria in its dissociated form will accumulate within the bacteria and disrupt many metabolic functions and lead to osmotic pressure increase, incompatible with the survival of the bacteria."
Vinegar is made up of water and acetic acid. Acetic acid is one of the simplest carboxylic acids. "The acetyl group, derived from acetic acid, is fundamental to the biochemistry of virtually all forms of life. When bound to coenzyme A it is central to the metabolism of carbohydrates and fats. However, the concentration of free acetic acid in cells is kept at a low level to avoid disrupting the control of the pH of the cell contents." "Acetic acid is also a component of the vaginal lubrication of humans and other primates, where it appears to serve as a mild antibacterial agent."
There are many different chemical forms of alcohol. In chemistry, an alcohol is any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group. Alcohols "are generally slightly weaker acids than water, but they are still able to react with strong bases such as sodium hydride or reactive metals such as sodium." The alcohol in vodka is ethanol. The addition of even a few percent of ethanol to water sharply reduces the surface tension of water. Ethanol can be oxidized to acetaldehyde, and further oxidized to acetic acid.
Vitamin C or L-ascorbate is also known as ascorbic acid. "L-ascorbate is a weak sugar acid structurally related to glucose which naturally occurs either attached to a hydrogen ion, forming ascorbic acid, or to a metal ion, forming a mineral ascorbate." Vitamin C is also a strong reducing agent. "A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction." The most important of these in out application is "denitrification, nitrate reduces to nitrogen in the presence of an acid." "Biological energy is frequently stored and released by means of redox reactions." Cellular respiration and photosynthesis involve a series of redox reactions.
Lets try to draw our conclusions from what we know to be true and not from speculation and anecdotal evidence.
Works cited: Wikipedia.
Amazing how that site can turn anyone into an expert.
Also, isn't it amazing what you can accomplish on a lunch break?
Pufferpunk
New member
Very interesting, thanks! With this knowladge, can someone please explain why they think this is helping my corals--especially zoas that were almost extinct in my tank, that are now thriving?
Skeptic_07
New member
I'm guessing it has something to do with the large reduction potential of L-ascorbate. heres a possibly related article that i didnt bother to read. i have to get back to work! :lol:
http://www.americanaquariumproducts.com/Redox_Potential.html
you can probably find more information by entering 'redox' and 'aquarium' into google.
http://www.americanaquariumproducts.com/Redox_Potential.html
you can probably find more information by entering 'redox' and 'aquarium' into google.
montanabay
New member
Here is my best attempt to explain what was going on (way back on page 34 of this thread) based on journal articles I found. It's not proven in an aquarium experiment, but I still think it is the best explanation,
jdiek actually summarized it for me pretty well (page 34 of thread)
"When the simbiotic zooxanthellae on the corals produce food by photosinthesys it also creates oxidants like oxygen peroxide that can damage the coral so the coral has to either create an antioxidant or expell the zooxanthellae (bleach) to get rid of it.
Vitamin C being an antioxidant could help the coral reduce the stress caused by the oxidants.
In other words the benefit of the vitamin is not because the coral uses it as a vitamin (like we do) but because the vitamin reduces the stress of the oxidants on the corals."
Support docs (find on page 33,34,35,36 of thread)
Montanabay Wrote:
This might be the most promising explanation to why V-C might be helping our corals. Essentially the coral tissue and symbiotic zooxanthellae are dramatically impacted by oxidants and oxyradical compounds. As a powerful antioxidant the dosing of V-C might be reducing the toxic effects of oxidation.
Here is some of the article (people with time please follow up on the references!)
Susceptibility to oxidative stress of the Mediterranean demosponge Petrosia ficiformis: role of endosymbionts and solar irradiance
F. Regoli1, C. Cerrano2, E. Chierici1, S. Bompadre3, G. Bavestrello4
1Istituto di Biologia e Genetica, Universit�_ di Ancona, Via Ranieri Monte D'Ago, 60100 Ancona, Italy Tel.: +39-071-2204613; Fax: +39-071-2204609 e-mail: regoli@popcsi.unian.it
2Dipartimento per lo Studio del Territorio e delle sue Risorse, Universit�_ di Genova, Via Balbi 5, 16126 Genova, Italy
3Istituto di Scienze Biomediche, Universit�_ di Ancona, Via Brecce Bianche, 60100 Ancona, Italy
4Istituto di Scienze del Mare, Universit�_ di Ancona, Via Brecce Bianche, 60100 Ancona, Italy
Abstract
The effects of elevated pO2 and irradiance as inducers of prooxidant conditions have been investigated in the Mediterranean demosponge Petrosia ficiformis (Poiret, 1789). This species lives symbiotically with the autotrophic cyanobacterium Aphanocapsa feldmanni, the abundance of which is controlled by the intensity of light irradiance. In the presence of symbionts, tissues of P. ficiformis were characterized by a general enhancement of antioxidant defenses as compared to aposymbiotic specimens. The main differences included higher activities of several antioxidant enzymes and a greater capability to neutralize various forms of oxyradicals, as indicated by the total oxyradical scavenging capacity (TOSC) assay. Elevated pO2, more than light, appeared to be the primary factor inducing prooxidant pressure in the Mediterranean sponge; in fact, irrespective of the solar irradiance experienced by the sponge, symbiotic specimens showed comparable activities of antioxidant enzymes and a similar scavenging capacity towards various reactive oxygen species. However, the potential toxicity of photodynamic production of reactive oxygen species was demonstrated in organisms from more irradiated sites, as the levels of antioxidant defenses were lowered in the outer layer of the sponge. The role of enhanced antioxidant defenses in protecting symbiotic specimens, also from oxyradical-mediated toxicity of light exposure, was supported by translocation experiments; aposymbiotic sponges did not survive when moved to conditions of elevated solar irradiance, while no effects were observed in symbiotic specimens if translocated and/or deprived of symbionts.
another interesting article
Photochem. Photobiol. Sci., 2007, 6, 842 - 847, DOI: 10.1039/b703119j
Photo-oxidative stress in symbiotic and aposymbiotic strains of the ciliate Paramecium bursaria
Paul H. Hörtnagl and Ruben Sommaruga
We tested the hypothesis that photo-oxidative stress is greater in symbiotic representatives of the freshwater ciliate Paramecium bursaria than in aposymbiotic (i.e., without Chlorella) ones. The level of oxidative stress was determined by assessing reactive oxygen species (ROS) with two fluorescent probes (hydroethidine and dihydrorhodamine123) by flow cytometry in exponential and stationary growth phases of both strains. Photo-oxidative stress was assessed in the laboratory after exposure of the ciliates to photosynthetically active radiation (PAR: 400ââ"šÂ¬Ã¢â‚¬Å“700 nm) and PAR + ultraviolet radiation (UVR: 280ââ"šÂ¬Ã¢â‚¬Å“400 nm). Additionally, both strains were screened for their antioxidant defenses by measuring the activity of the enzymes catalase, superoxide dismutase (SOD), and glutathione reductase. The results showed that aposymbiotic ciliates had higher levels of PAR-induced oxidative stress than symbiotic ones. Significant differences in PAR-induced oxidative stress were also found in both strains when comparing exponential and stationary growth phases with generally higher values in the former. After exposure to UVR, aposymbiotic ciliates in the stationary phase had the highest levels of ROS despite an increase in SOD activity. By contrast, exposure to UVR decreased catalase activity in both strains. Overall, our results suggest that in this ciliate symbiosis, the presence of symbionts minimizes photo-oxidative stress. This work represents the first assessment of photo-oxidative stress in an algal-ciliate mutualistic symbiosis.
more:http://www.int-res.com/articles/mep...75/m275p129.pdf
Seasonal variability of prooxidant pressure and antioxidant adaptation to symbiosis in the Mediterranean demosponge Petrosia ficiformis
F. Regoli1,*, C. Cerrano2, E. Chierici1, M. C. Chiantore2, G. Bavestrello3
1Istituto di Biologia e Genetica, Universit�_ Politecnica delle Marche, Via Ranieri, Monte Dââ"šÂ¬Ã¢"žÂ¢Ago, 60100 Ancona, Italy
2Dipartimento per lo Studio del Territorio e delle sue Risorse, Universit�_ di Genova, Via Balbi 5, 16126 Genova, Italy
3Dipartimento di Scienze del Mare, Universit�_ Politecnica delle Marche, Via Brecce Bianche, 60100 Ancona, Italy
ABSTRACT: In symbioses between invertebrates and microalgae, host tissues are exposed to
increased levels of photosynthetically produced oxygen. The biochemical consequences of symbioses
have been poorly investigated in Mediterranean species, but a general increase in antioxidant
defences has been recently reported in the demosponge Petrosia ficiformis as an adaptive response
to the cyanobacterium Aphanocapsa feldmanni. Since Mediterranean symbioses naturally experience
marked seasonal variations in symbiont content, light intensity and seawater temperature, the
aim of this work was to investigate if these fluctuations modulate the prooxidant challenge to sponge
tissues. Antioxidant efficiency was characterised on a monthly basis by combining an analysis of the
main antioxidants (superoxide dismutase, catalase, glutathione S-transferases, glutathione reductase,
glutathione peroxidases) with measurements of the total oxyradical scavenging capacity
(TOSC), thus achieving a more holistic assessment of the capacity of sponge tissues to absorb different
forms of reactive oxygen species. Symbiotic sponges showed significant seasonal changes in
antioxidant efficiency, with more marked variations in tissues directly exposed to photosynthetically
produced reactive oxygen species. The greatest variations were observed during the summer
months, with the highest seasonal values for some defences (i.e. catalase) and the lowest for others
(i.e. glutathione peroxidases). The marked increase in catalase and TOSC in summer suggests
greater production of H2O2 in the symbioses during this period, supporting the hypothesis that seawater
temperature can significantly modulate the prooxidant challenge in Mediterranean symbioses.
The results suggest that species with lower antioxidant efficiency may be less tolerant of conditions
effecting oxidative damage; e.g. increases in temperature during the summer months.
KEY WORDS: Mediterranean symbioses ââ"šÂ¬Ã‚¢ Oxyradicals ââ"šÂ¬Ã‚¢ Antioxidants ââ"šÂ¬Ã‚¢ Adaptation ââ"šÂ¬Ã‚¢ Sensitivity ââ"šÂ¬Ã‚¢
Temperature ââ"šÂ¬Ã‚¢ Demosponge
jdiek actually summarized it for me pretty well (page 34 of thread)
"When the simbiotic zooxanthellae on the corals produce food by photosinthesys it also creates oxidants like oxygen peroxide that can damage the coral so the coral has to either create an antioxidant or expell the zooxanthellae (bleach) to get rid of it.
Vitamin C being an antioxidant could help the coral reduce the stress caused by the oxidants.
In other words the benefit of the vitamin is not because the coral uses it as a vitamin (like we do) but because the vitamin reduces the stress of the oxidants on the corals."
Support docs (find on page 33,34,35,36 of thread)
Montanabay Wrote:
This might be the most promising explanation to why V-C might be helping our corals. Essentially the coral tissue and symbiotic zooxanthellae are dramatically impacted by oxidants and oxyradical compounds. As a powerful antioxidant the dosing of V-C might be reducing the toxic effects of oxidation.
Here is some of the article (people with time please follow up on the references!)
Susceptibility to oxidative stress of the Mediterranean demosponge Petrosia ficiformis: role of endosymbionts and solar irradiance
F. Regoli1, C. Cerrano2, E. Chierici1, S. Bompadre3, G. Bavestrello4
1Istituto di Biologia e Genetica, Universit�_ di Ancona, Via Ranieri Monte D'Ago, 60100 Ancona, Italy Tel.: +39-071-2204613; Fax: +39-071-2204609 e-mail: regoli@popcsi.unian.it
2Dipartimento per lo Studio del Territorio e delle sue Risorse, Universit�_ di Genova, Via Balbi 5, 16126 Genova, Italy
3Istituto di Scienze Biomediche, Universit�_ di Ancona, Via Brecce Bianche, 60100 Ancona, Italy
4Istituto di Scienze del Mare, Universit�_ di Ancona, Via Brecce Bianche, 60100 Ancona, Italy
Abstract
The effects of elevated pO2 and irradiance as inducers of prooxidant conditions have been investigated in the Mediterranean demosponge Petrosia ficiformis (Poiret, 1789). This species lives symbiotically with the autotrophic cyanobacterium Aphanocapsa feldmanni, the abundance of which is controlled by the intensity of light irradiance. In the presence of symbionts, tissues of P. ficiformis were characterized by a general enhancement of antioxidant defenses as compared to aposymbiotic specimens. The main differences included higher activities of several antioxidant enzymes and a greater capability to neutralize various forms of oxyradicals, as indicated by the total oxyradical scavenging capacity (TOSC) assay. Elevated pO2, more than light, appeared to be the primary factor inducing prooxidant pressure in the Mediterranean sponge; in fact, irrespective of the solar irradiance experienced by the sponge, symbiotic specimens showed comparable activities of antioxidant enzymes and a similar scavenging capacity towards various reactive oxygen species. However, the potential toxicity of photodynamic production of reactive oxygen species was demonstrated in organisms from more irradiated sites, as the levels of antioxidant defenses were lowered in the outer layer of the sponge. The role of enhanced antioxidant defenses in protecting symbiotic specimens, also from oxyradical-mediated toxicity of light exposure, was supported by translocation experiments; aposymbiotic sponges did not survive when moved to conditions of elevated solar irradiance, while no effects were observed in symbiotic specimens if translocated and/or deprived of symbionts.
another interesting article
Photochem. Photobiol. Sci., 2007, 6, 842 - 847, DOI: 10.1039/b703119j
Photo-oxidative stress in symbiotic and aposymbiotic strains of the ciliate Paramecium bursaria
Paul H. Hörtnagl and Ruben Sommaruga
We tested the hypothesis that photo-oxidative stress is greater in symbiotic representatives of the freshwater ciliate Paramecium bursaria than in aposymbiotic (i.e., without Chlorella) ones. The level of oxidative stress was determined by assessing reactive oxygen species (ROS) with two fluorescent probes (hydroethidine and dihydrorhodamine123) by flow cytometry in exponential and stationary growth phases of both strains. Photo-oxidative stress was assessed in the laboratory after exposure of the ciliates to photosynthetically active radiation (PAR: 400ââ"šÂ¬Ã¢â‚¬Å“700 nm) and PAR + ultraviolet radiation (UVR: 280ââ"šÂ¬Ã¢â‚¬Å“400 nm). Additionally, both strains were screened for their antioxidant defenses by measuring the activity of the enzymes catalase, superoxide dismutase (SOD), and glutathione reductase. The results showed that aposymbiotic ciliates had higher levels of PAR-induced oxidative stress than symbiotic ones. Significant differences in PAR-induced oxidative stress were also found in both strains when comparing exponential and stationary growth phases with generally higher values in the former. After exposure to UVR, aposymbiotic ciliates in the stationary phase had the highest levels of ROS despite an increase in SOD activity. By contrast, exposure to UVR decreased catalase activity in both strains. Overall, our results suggest that in this ciliate symbiosis, the presence of symbionts minimizes photo-oxidative stress. This work represents the first assessment of photo-oxidative stress in an algal-ciliate mutualistic symbiosis.
more:http://www.int-res.com/articles/mep...75/m275p129.pdf
Seasonal variability of prooxidant pressure and antioxidant adaptation to symbiosis in the Mediterranean demosponge Petrosia ficiformis
F. Regoli1,*, C. Cerrano2, E. Chierici1, M. C. Chiantore2, G. Bavestrello3
1Istituto di Biologia e Genetica, Universit�_ Politecnica delle Marche, Via Ranieri, Monte Dââ"šÂ¬Ã¢"žÂ¢Ago, 60100 Ancona, Italy
2Dipartimento per lo Studio del Territorio e delle sue Risorse, Universit�_ di Genova, Via Balbi 5, 16126 Genova, Italy
3Dipartimento di Scienze del Mare, Universit�_ Politecnica delle Marche, Via Brecce Bianche, 60100 Ancona, Italy
ABSTRACT: In symbioses between invertebrates and microalgae, host tissues are exposed to
increased levels of photosynthetically produced oxygen. The biochemical consequences of symbioses
have been poorly investigated in Mediterranean species, but a general increase in antioxidant
defences has been recently reported in the demosponge Petrosia ficiformis as an adaptive response
to the cyanobacterium Aphanocapsa feldmanni. Since Mediterranean symbioses naturally experience
marked seasonal variations in symbiont content, light intensity and seawater temperature, the
aim of this work was to investigate if these fluctuations modulate the prooxidant challenge to sponge
tissues. Antioxidant efficiency was characterised on a monthly basis by combining an analysis of the
main antioxidants (superoxide dismutase, catalase, glutathione S-transferases, glutathione reductase,
glutathione peroxidases) with measurements of the total oxyradical scavenging capacity
(TOSC), thus achieving a more holistic assessment of the capacity of sponge tissues to absorb different
forms of reactive oxygen species. Symbiotic sponges showed significant seasonal changes in
antioxidant efficiency, with more marked variations in tissues directly exposed to photosynthetically
produced reactive oxygen species. The greatest variations were observed during the summer
months, with the highest seasonal values for some defences (i.e. catalase) and the lowest for others
(i.e. glutathione peroxidases). The marked increase in catalase and TOSC in summer suggests
greater production of H2O2 in the symbioses during this period, supporting the hypothesis that seawater
temperature can significantly modulate the prooxidant challenge in Mediterranean symbioses.
The results suggest that species with lower antioxidant efficiency may be less tolerant of conditions
effecting oxidative damage; e.g. increases in temperature during the summer months.
KEY WORDS: Mediterranean symbioses ââ"šÂ¬Ã‚¢ Oxyradicals ââ"šÂ¬Ã‚¢ Antioxidants ââ"šÂ¬Ã‚¢ Adaptation ââ"šÂ¬Ã‚¢ Sensitivity ââ"šÂ¬Ã‚¢
Temperature ââ"šÂ¬Ã‚¢ Demosponge
toaster77
New member
right on, montana. here's another:
Ascorbate biosynthesis and function in photoprotection.
N Smirnoff
School of Biological Sciences, University of Exeter, Hatherly Laboratories, UK. n.smirnoff@exeter.ac.uk
This article has been cited by other articles in PMC.
ABSTRACT
Ascorbate (vitamin C) can reach very high concentrations in chloroplasts (20-300 mM). The pool size in leaves and chloroplasts increases during acclimation to high light intensity and the highest concentrations recorded are in high alpine plants. Multiple functions for ascorbate in photosynthesis have been proposed, including scavenging of active oxygen species generated by oxygen photoreduction and photorespiration, regeneration of alpha-tocopherol from alpha-tocopheryl radicals, cofactor for violaxanthin de-epoxidase and donation of electrons to photosystem II. Hydrogen peroxide scavenging is catalysed by ascorbate peroxidase (Mehler peroxidase reaction) and the subsequent regeneration of ascorbate by reductant derived from photosystem I allows electron flow in addition to that used for CO2 assimilation. Ascorbate is synthesized from guanosine diphosphate-mannose via L-galactose and L-galactono-1,4-lactone. The last step, catalysed by L-galactono-1,4-lactone dehydrogenase, is located on the inner mitochondrial membrane and uses cytochrome c as electron acceptor. L-galactono-1,4-lactone oxidation to ascorbate by intact leaves is faster in high-light acclimated leaves and is also enhanced by high light, suggesting that this step contributes to the control of pool size by light. Ascorbate-deficient Arabidopsis thaliana vtc mutants are hypersensitive to a number of oxidative stresses including ozone and ultraviolet B radiation. Further investigation of these mutants shows that they have reduced zeaxanthin-dependent non-photochemical quenching, confirming that ascorbate is the cofactor for violaxanthin de-epoxidase and that availability of thylakoid lumen ascorbate could limit this reaction. The vtc mutants are also more sensitive to photo-oxidation imposed by combined high light and salt treatments.
Ascorbate biosynthesis and function in photoprotection.
N Smirnoff
School of Biological Sciences, University of Exeter, Hatherly Laboratories, UK. n.smirnoff@exeter.ac.uk
This article has been cited by other articles in PMC.
ABSTRACT
Ascorbate (vitamin C) can reach very high concentrations in chloroplasts (20-300 mM). The pool size in leaves and chloroplasts increases during acclimation to high light intensity and the highest concentrations recorded are in high alpine plants. Multiple functions for ascorbate in photosynthesis have been proposed, including scavenging of active oxygen species generated by oxygen photoreduction and photorespiration, regeneration of alpha-tocopherol from alpha-tocopheryl radicals, cofactor for violaxanthin de-epoxidase and donation of electrons to photosystem II. Hydrogen peroxide scavenging is catalysed by ascorbate peroxidase (Mehler peroxidase reaction) and the subsequent regeneration of ascorbate by reductant derived from photosystem I allows electron flow in addition to that used for CO2 assimilation. Ascorbate is synthesized from guanosine diphosphate-mannose via L-galactose and L-galactono-1,4-lactone. The last step, catalysed by L-galactono-1,4-lactone dehydrogenase, is located on the inner mitochondrial membrane and uses cytochrome c as electron acceptor. L-galactono-1,4-lactone oxidation to ascorbate by intact leaves is faster in high-light acclimated leaves and is also enhanced by high light, suggesting that this step contributes to the control of pool size by light. Ascorbate-deficient Arabidopsis thaliana vtc mutants are hypersensitive to a number of oxidative stresses including ozone and ultraviolet B radiation. Further investigation of these mutants shows that they have reduced zeaxanthin-dependent non-photochemical quenching, confirming that ascorbate is the cofactor for violaxanthin de-epoxidase and that availability of thylakoid lumen ascorbate could limit this reaction. The vtc mutants are also more sensitive to photo-oxidation imposed by combined high light and salt treatments.
Skeptic_07
New member
nice fillabuster.
the first absract you have sighted has something to do with sponges. The second is about a protozoa more specifically paramecium. the third is again about a sponge. I dont see what any of this has to do with what we are doing.
I can't figure out what this 'oxygen peroxide' actually is. the term itself is redundant like saying chocolate fudge. "A peroxide is a compound containing an oxygen-oxygen single bond." So i guess oxygen peroxide would be ... ozone? *shrugs* ozone helps greatly in lowering redox readings, which is what you want, -250 or so.
the first absract you have sighted has something to do with sponges. The second is about a protozoa more specifically paramecium. the third is again about a sponge. I dont see what any of this has to do with what we are doing.
I can't figure out what this 'oxygen peroxide' actually is. the term itself is redundant like saying chocolate fudge. "A peroxide is a compound containing an oxygen-oxygen single bond." So i guess oxygen peroxide would be ... ozone? *shrugs* ozone helps greatly in lowering redox readings, which is what you want, -250 or so.
Skeptic_07
New member
toaster: care to explain that post to the rest of us in more simple terms? I'm particularly interested in this snippet:
the rest is about how cells produce vitamin c which isn't really relevent.
the rest is about how cells produce vitamin c which isn't really relevent.
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