Accuracy of the director of the publication :
The content of news and the approach of the science collaborative, encouraging, and we will cover this topic. In confinement, the people have had time to deepen their research and delve into the scientific literature. They do not call in question the state of the science, but allow themselves to get off the beaten track to make assumptions and seek to validate them. We are once again in the thesis of the initial internet, which put in advance the collaborative research and the contribution to the resolution of a medical problem. The work of these people are published to demonstrate their desire for contribution. The gray matter exists, and it is interesting to make use of it. This document is for information purposes and is not intended to be a scientific research accomplished, but represents the research work of its editor. We point out to the reader that it is the purpose of collaborative research in order to contribute to the research.
ANALYSIS : Prevotella Copri plays a role in the Covid-19 : But in what measures ?
In the preceding section, we found that the nature of the microbiota had a direct influence on the manifestation of inflammatory phenomena . In this case, transplantation of the microbiota of a mutant mouse of laboratory to a wild-type mouse healthy leads to many inflammatory phenomena, in particular on the epithelial cells of the intestine which are present in many molecules of the enzyme ACE2, the gateway to the SARS-COV2.
For many reasons, observational, whose synthesis has been made previously , the assumption that Prevotella copri, could play an important role has been raised.
More particularly, the sub-species of Prevotella copri with a decline in their genetic diversity (sub-species characteristic of developed countries (westernized) could play a major role in the infectivity Covid-19. In fact, in a recent publication of the November 2019 , researchers have highlighted that the distribution of sub-species of Prevotella copri was significantly correlated with the mode of life of the countries in the modern westernized, those who are precisely the most affected by the Coivd-19. They also show that Prevotella copri is frequently correlated to certain pathogens.
The question remains, therefore, to be able to apreciate the extent of the potential role of Prevotella copri in the Covid and to understand the cellular mechanisms in play. We will try, therefore, to advance a few arguments based on the scientific literature. First we will see the role of the microbiota in a viral infection, then that amino acids play an important role in the expression of this microbiota. We will show later how some amino acids can directly aggravate the manifestations of the Covid-19.
The influence of the microbiota on the infectivity of a virus may be great
The nature of the microbiota could play a direct influence on the manifestation of inflammatory phenomena. However, we have not yet appreciated the scope that can play the virus SARS-COV2 in this global table. To do this, it was necessary to assess more globally the extent of the infectivity of a virus in function of the microbiota.
In an american study of 2017 , researchers have tried to observe the influence of the gut microbiota in the immune response against an influenza virus. Thus, wild mice (with a microbiota natural) and mutant mice (with a microbiota germ-free) laboratory have been exposed to the Influenza virus A (influenza virus). 83 % of mutant mice (non-wild) died in the 13 days following infection, but only 8% of wild-type mice. In addition, the histopathological lesions, including tissues, bronchial, and lung, were attenuated in wild-type mice. The quantification in the lung cytokines and chemokines (immune system responses) expressed four days after infection revealed a very strong expression of chemokines and pro-inflammatory cytokines in mutant mice (referring to a “storm” cytokinique), contrary to the wild in which the anti-inflammatory cytokines were dominant .
In function of the microbiota, thus we find that the ratio of mortality is 1 to 10. This is not negligible. There is also an array of symptoms reminiscent of the Covid-19.
Of course, mice are not men, but this gives to reflect on the character very discriminant of the microbiota in the context of a viral infection.
The quality of the amino acids is a discriminating factor in the expression of the microbiota
In a 2012 publication (published in Nature  for an experiment on the microbiota of the mouse, in order to study the effect of amino acids on the inflammatory phenomena, the researchers give the mice an essential amino acid (not little or synthesized by man) called Tryptophan.
They show several things : The first is that the transplantation simple of the microbiota of the mutant mice patients to the wild-type mice was sufficient to cause inflammatory phenomena at the level of the intestine. However, they demonstrate that the intake of Tryptophan would reduce the character inflammatory on wild mice which were transplanted to a microbiota-pathogenic. In other words, the inflammatory factor discriminating variable in this experiment is in the second analysis of the intake of tryptophan. It is therefore the role discriminant of the biosynthesis of amino acids by the microbiota is highlighted here.
The intake of amino acids is, therefore, bound in this experiment the inflammatory events of the gut. The cellular mechanisms that can aggravate the forms of Covid-19
We have also seen that the enzyme ACE2, the gateway to the SARS-COV2, played an important role in the Covid-19 . In effect, the enzyme ACE2 are present on the epithelia (tissues that are found in certain parts of the body), which exhibit inflammation as part of the Covid-19. In addition, the tables of symptoms of Covid-19 the most serious feature of the phenomena of vasoconstriction.
How do you explain this ?
The role of ACE2 is to catalyze the conversion of protein called angiotensin. This catalysis involves the amino acids. It is therefore at the heart of the regulation of the renin-angiotensin system.
More specifically, the ACE2 converts angiotensin I to 1-10 (decapeptide) angiotensin 1-9 (nonapeptide), and angiotensin II 1-8 (octapeptide-inducing vasoconstriction) angiotensin 1-7 (heptapeptide with vasodilatory properties).
If the tables Covid-19 are the phenomena of vasoconstriction, it is, therefore, that the transformation of the angiotensin II 1-8 (octapeptide-inducing vasoconstriction) is probably disturbed in the framework of the Covid-19.
In other words, the SARS-COV2 disrupts very probably the enzymatic activity of the ACE2 slowing down or suppressing the catalytic effect.
Let’s look at the operation schematic of this enzyme :
But in what measures ?
We observe here that if the virus SARS-COV2 slows down or prevents the catalysis of ACE2, this means two things :
(2) : angiotensin I (1-10) (the one with 10 amino acids represented by the color balls) is no more than partially degraded normally by the ace1 antibody only because the ACE2 is no longer working properly.
(4) : The angiotensin II (1-8) (one that have 8 amino acids represented by the colored balls), that has properties vasoconstrictrices is not degraded normally by ACE2 to generate angiotensin – (1-7)
The production of angiotensin – (1-7), which passes necessarily by ACE2 is constrained by the SARS-COV2. On the other hand the production of angiotensin II (1-8) (octapeptide-inducing vasoconstriction) continues normally.
The amino acid type of BCAA’s are correlated with some factors of co-morbidities of the Covid-19
In a study published in 2018 in the scientific journal Nature , the researchers show that high levels of amino acid side-chain-branched (the acronym of which common is BCAAS) which inhibits the proper metabolism of glucose and are binding on such high levels with cardiomyocytes (cardiac disorders).
Similarly, the failure of the catabolism of these amino acids BCAA, which lead to their accumulation are very strongly correlated with cancers of the liver , or to phenomena of insulin resistance  in diabetics, it is known that they have a field-inflammatory.
More specifically, it has been shown in rats that one of these amino acid type (BCAA), namely leucine (Leu), was positively correlated to the production of angiotensin II .
Prevotella Copri promotes the biosynthesis of amino acids of type BCAA’s, whose accumulation is known to be pathogenic
At this stage, it is important to remember that the BCAA amino acids are ” essential amino acids “, that is to say amino acids which are not metabolized in sufficient quantity by the human body.
However, a publication in Danish of 2016 published in the journal Nature  showed that the bacterium Prevotella copri synthesised it-even the amino acids BCAAS. In this study, the researchers studied the microbiota and metabolites in the presence in 277 Danish non-diabetic as compared with those of 75 Danish patients with type 2 diabetes.
The study reveals that diabetic patients have a serum metabolic rich in amino acids type of BCAA, and that there is a net correlation with their microbiota.
The microbiota of patients with diabetes presents in effect an over-representation on two bacteria : Prevotella copri and Bacteroides vulgatus. These two bacteria are clearly identified as factors correlated to the biosynthesis of amino acids BCAA and insulin resistance.
Furthermore, in order to determine the role of these two bacteria, the researchers have made an experiment on mice which showed that Prevotella Copri was the factor which involved the insulin resistance.
The protein of the SARS-COV 2 contain a high concentration of BCAA’s
Finally, it appears that the proteins of SARS-Cov2 contain a high amount of isoleucine and valine  (which are BCAA’s), as the virus is also composed of 57.4% of the essential amino acids.
The replication capacity of the virus could probably be impacted by the availability of these amino acids in the body. Studies have shown, including HIV , the concentration of lysine is promoting its replication.
Gold Prevotella copri biosynthétise strongly these two amino acids a component of the SARS-Cov2.
Prevotella Copri, a track solid and concrete
Prevotella copri is a marker of entérotypes and the microbiota, the latter playing an important role in the infectivity of the virus.
Prevotella copri is also a discriminating factor in the levels of BCAAS. However, it has been shown that the composition of the microbiota in amino acids can determine the expression of the inflammatory phenomena. It has also been shown that the levels of BCAA were a factor correlated to certain comorbidities while these amino acids are also involved in the dysregulation of the renin-angiotensin system.
For all these reasons cumulative, it seems to us possible that Prevotella copri plays in the worsening of the symptoms of the Covid-19. By analogy with the mouse model referred to, it is not impossible that this factor is truly determinant for some people.
Moreover, Prevotella copri may provide in abundance relative to the virus-the amino acid required for its replication, which would have an influence on its virality. It is, therefore, a strong track in which the overall influence should be checked.
It is also possible to study quite quickly the correlation between the relative lack of genetic diversity of the sub-classes of Prevotella copri in the intestinal flora and the severity of the symptoms observed in the Covid-19.
It might also be interesting to study more generally the prevalence of other species resulting in accumulation of BCAAS, in correlation with the onset of symptoms cardiovascular.
Author(s): Igaal HANOUNA for FranceSoir