# Can someone explain Rubisco to me?



## Sacha (30 Jan 2014)

I'm struggling to understand exactly what Rubisco is and what role it plays in plants' self- regulation. Can someone give me a brief explanation of what it is please? 

Thanks.


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## dw1305 (30 Jan 2014)

Hi all, 





Sacha said:


> xactly what Rubisco is and what role it plays in plants' self- regulation


 I'm not a plant physiologist, but it is the enzyme that is the first step in fixing inorganic carbon (CO2) in photosynthesis, and occurs in all photosynthetic organisms. It catalyses the production RuBP. <Photosynthesis>

Have a look at the "Calvin cycle" (Wikipedia should do), but I think it is one if the compounds that is likely to be damaged if you have excess photons.

cheers Darrel


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## tim (30 Jan 2014)

Rubisco


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## tim (30 Jan 2014)

^^ what Darrel said


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## parotet (30 Jan 2014)

Rubisco is the anwer to most of our problems. That's what I learnt here 

Now seriously, I've read a Little bit about Rubisco during the last weeks thanks to some members here (I love to read some nights about enzymes, other nights about O dissolution, amazonian fish... great hobby, isn't it?), but my question is... algae use also Rubisco to get their CO2, but as it has been mentioned several times they can "adapt their Rubisco" much faster, but why/how? Is it not the same enzyme?


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## ceg4048 (30 Jan 2014)

Non-geeks, who do not have the time or energy to obtain a Master's Degree in Rocket Science, may also refer to the discussion in EI calculators | UK Aquatic Plant Society

Cheers,


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## zanguli-ya-zamba (30 Jan 2014)

ceg4048 said:


> Non-geeks, who do not have the time or energy to obtain a Master's Degree in Rocket Science, may also refer to the discussion in EI calculators | UK Aquatic Plant Society
> 
> Cheers,



I have re read it !!! Great reading thanks


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## parotet (31 Jan 2014)

ceg4048 said:


> Non-geeks, who do not have the time or energy to obtain a Master's Degree in Rocket Science, may also refer to the discussion in EI calculators | UK Aquatic Plant Society
> 
> Cheers,


Yes, it's him the one that is guilty for introducing Rubisco in our life... I just wanted some nice plants in a glass cube and I ended up reading about rocket science!


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## NatureBoy (1 Feb 2014)

Reading this from Darrel's link, I wonder whether algae is less capable of preventing RuBisCo attaching to oxygen? So in an oxygen enriched environment primitive algae species actually lose energy whereas higher plants can cope....maybe this is why we see methods that serve to enrich the water with oxygen - water change, H2O2, perhaps also the twinstar, see a decline in algae's ability to grow and even waste away. Perhaps oxygen is the key?

"One of the biggest _faux pas_ (that's French for big "mistakes") of evolution RuBisCo is not only attracted to CO2, but it can also use O2 in the Calvin-Benson Cycle

When O2 is used in the Calvin-Benson Cycle, no energy is stored - in fact, energy is lost!
The reaction is as follows: O2 + RUBP 


 1 PGA + 1 Phosphogylcolate
There is very little use for phosphoglycolate in the plant, so the plant must spend energy to convert the phosphoglycolate back to a useful molecule and reclaim the two carbons
The conversion of phosphyglycolate occurs in the peroxysome

Why does photorespiration occur?

When this evolved, the concentration of O2 was low - this was not a problem
Plants have since evolved ways to reduce the damage caused by O2 in the Calvin-Benson Cycle
Plants must spend up to 40% of their energy stored in sugars to deal with the damage created by RuBisCo fixing O2 in the Calvin-Benson Cycle"


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## NatureBoy (1 Feb 2014)

hmm, seems algae solved the problem of oxygenated water with this Pyrenoid | CAPP


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## NatureBoy (1 Feb 2014)

but then again: "Pyrenoids are highly plastic structures and the degree of Rubisco packaging correlates with the state of induction of the CCM. In _Chlamydomonas_, when the CCM is repressed, for example when cells are maintained in a CO2-rich environment, the pyrenoid is small and the matrix is unstructured." Pyrenoid - Wikipedia, the free encyclopedia

so in a CO2 injected tank the algae get lazy in their CCM mechanism and the rubisco could be more susceptible to getting swamped with oxygen  

going off on one here, sorry


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## ceg4048 (1 Feb 2014)

Algae love CO2 as much as plants do. They do not suffer when the Oxygen levels are high and they have simpler and more elegant Carbon fixing systems as mentioned in the Pyrenoid article...and they are smaller and require less of everything. They are also tuned to changing environments. That is their niche. They do not get lazy. They are the predators. Plants are the ones that get lazy. That's why algal blooms erupt so quickly.

The better way to think about it is that plants do better when there is a higher Oxygen level for lots of different reasons, not the least of which is the requirement at night for Oxygen when there is zero Oxygen production. So the plants are healthier and they resist algae attacks.There is very little that algae cannot do better than plants. This is why plants cannot compete with algae. Algae is not afraid of Oxygen, high or low.

Cheers,


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## Sacha (1 Feb 2014)

Clive if Algae love Co2, then how come you say that hair algae is caused by low Co2?


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## ceg4048 (1 Feb 2014)

Because THE PLANTS SUFFER  when CO2 is low.

Try not to think about what algae want. Try only to think about what plants want.
Algae respond to the status of the plants.
They have sensors that determine when the plants are suffering and when the environmental conditions are not favorable to plants. They do not really care what the actual values of these parameters are for themselves, only what effect those parameters have on the plants.

When plants are suffering an acute deficiency they actually leak more nutrients and organic products out into the water in what might be likened to diarrhea. Algal spores are sitting on top of the leaf and the spores can sense the release of these products, such as PO4 for example. So the logic in the algal spore monitors the PO4 output and can tell that if so much PO4 is leaking, then the plant is ill and it is a good time to attack.

So do not misinterpret this as "PO4 causes algae" but rather; "an increase in PO4 leakage from the plant tissue indicates a cell rupture and that means the prey is susceptible to attack"

Algae have been around for billions of years and they are not as simpleton as what The Matrix makes them out to be. The Oxygen you are breathing right now was most likely produced by algae. They rule.

Cheers,


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## darren636 (1 Feb 2014)

So, why can't the algae just grow by itself. If these nutrients are available- why the need to care about what's going on with the plants,? Surely the evironment is suitable for both. At the same time?


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## plantbrain (2 Feb 2014)

darren636 said:


> So, why can't the algae just grow by itself. If these nutrients are available- why the need to care about what's going on with the plants,? Surely the evironment is suitable for both. At the same time?


 

Why are there more than 1 species of algae then?
The logic you present is the same as my question to you.


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## Sacha (2 Feb 2014)

Clive, that makes a lot of sense. Thanks for that explanation.


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## NatureBoy (2 Feb 2014)

ceg4048 said:


> There is very little that algae cannot do better than plants. This is why plants cannot compete with algae


 
Hi Clive, then how did plants evolve to rise above a blanket of algae? Areas that plants have invested a lot of time getting good at is storing energy, alternative photosynthetic highways, and potentially (or as a byproduct) generating allelopathic chemicals. They are less boom and bust merchants than algae, financial planners could do well comparing the two!



ceg4048 said:


> Algae is not afraid of Oxygen, high or low


Is this proven? and true of all the algal species? Perhaps it is less true of hair algae and bga and more true of bba, perhaps lower oxygen levels are one of an algal spores triggers that a system is not healthy and susceptible to attack? etc...



ceg4048 said:


> When plants are suffering an acute deficiency they actually leak more nutrients and organic products out into the water in what might be likened to diarrhea. Algal spores are sitting on top of the leaf and the spores can sense the release of these products, such as PO4 for example. So the logic in the algal spore monitors the PO4 output and can tell that if so much PO4 is leaking, then the plant is ill and it is a good time to attack.


 
This sounds plausible and mirrors the stages of algal growth on a nutrient deficient leaf, but is the mechanism and type of "trigger" chemicals scientifically identified and proven or it more a reasonable hunch of what is going on based on experience, I like to read about this kind of thing, so if you have the references then please attach them.

cheers


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## ceg4048 (2 Feb 2014)

NatureBoy said:


> Hi Clive, then how did plants evolve to rise above a blanket of algae? Areas that plants have invested a lot of time getting good at is storing energy, alternative photosynthetic highways, and potentially (or as a byproduct) generating allelopathic chemicals. They are less boom and bust merchants than algae, financial planners could do well comparing the two!


Hi mate,
			 Plants do not inhabit the same niche in nature that algae do. That's the one thing that people forget. The success and longevity of algae and other spore creating species is in many ways facilitated by the spore. Spores live forever, practically speaking. The best reason for any algae to bloom is in order to produce more spores which also live forever. So it isn't that the world was covered with algae 24/7 and plants somehow managed to poke their head above it. Being in the green state and having to feed cells is an expensive affair, so the algae bloom when conditions are more favorable for them. If it's cooler or darker, for example, then it's best to remain as a spore.

Plants have a different nice, so there is plenty of time to grow and develop when algae are spores. As long as they stay healthy then the blooms do not occur. Plants prefer a stable set of conditions because it takes them a long time to re-configure their chemistry for any new conditions. Algae respond instantaneously to change, especially if the change can be to their benefit. So it's a chess game. "When are conditions favorable for plants and when are they not?"




NatureBoy said:


> ceg4048 said: ↑ Algae is not afraid of Oxygen, high or low Is this proven? and true of all the algal species? Perhaps it is less true of hair algae and bga and more true of bba, perhaps lower oxygen levels are one of an algal spores triggers that a system is not healthy and susceptible to attack? etc...


Well, you know that there are tens of thousands of algal species as well as thousands of different systems. I can't say very much about all species, just the few that are in our tanks. Obviously, we do not see tens of thousands of different species. We see a few varieties in a couple of categories, and that's because the conditions in our tanks can be favorable to only that few.

Since BGA typically lives in a place that is more susceptible to a decline in Oxygen it can be that O2 used as a stronger trigger for that species but perhaps less so for the others that you mention. I don't know that for sure.



NatureBoy said:


> This sounds plausible and mirrors the stages of algal growth on a nutrient deficient leaf, but is the mechanism and type of "trigger" chemicals scientifically identified and proven or it more a reasonable hunch of what is going on based on experience, I like to read about this kind of thing, so if you have the references then please attach them.


No, there is a lot we still don't know. We have some measurements  of the leakage, and that happens simply due to the breakdown of the cell walls and the release of the cell contents. There may be other materials that the spores sense as well.  plantbrain will have more information on that.




darren636 said:


> So, why can't the algae just grow by itself. If these nutrients are available- why the need to care about what's going on with the plants,? Surely the evironment is suitable for both. At the same time?


 
It's exactly as Tom mentions above. Lots of different conditions, lots of different prey, lots of different mechanisms to survive and reproduce. If plants are around, then life can become easier. A place to anchor without being washed away, for example, while being fed at the same time.

The idea that we are trying to deliver is that we need to stop thinking about the cause of blooms solely in terms of whether we added NO3 or not, because blooms are triggered by a vast array and very complicated set of conditions, many of which we do not yet have control over, and many of which are totally unrelated to what the nutrient levels are.

Cheers,


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## plantbrain (2 Feb 2014)

So focus on growing plants well, then you do not have to deal with much algae issues, only minor annoyances. 
I use the forest example: Why are there forest? Why are they not overtaken with weeds? Well, if you come in and chop the forest down, then weeds will take over, if you chop down just a little area then the weeds come in and then die off after a few years once the trees grow back in.

Rainforest are very much like this. Many species, many angles trying to occupy space and time.
Why are there not more weeds and mono cultures in Rainforest? 

Most aquatic plant beds in nature are mono cultures of 2-3 species. 

Rubisco is the largest enzymatic expenditure and it's not that efficient. Plants can make more/less over time, generally weeks etc, algae can responds much much faster. 
If you have a lot more, it comes with a price..............if you have less, that also comes with a price. Degrading it and making more takes a lot of effort so if the CO2 levels are not stable, eg, all over the place, the plant cannot regulate well, the algae think good times are coming, so they go nuts.

Plants on the other hand, stunt.

What are the signals?
CO2 seems to be the biggest one.
Secondary effects, such as increases in the COD, organic loading etc seem to correlate well with algae, even if the CO2 is relatively stable.


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