Gut Microbiota Might Act as a Potential Therapeutic Pathway in COVID-19.

It has been very recently suggested that individuals with chronic gut inflammation are highly susceptible to COVID-19. They constitute the serious cases of COVID-19, in which inflammatory cytokine storm is observed. On the contrary, the healthy gut microbiota is linked with low chronic gut and systemic inflammation. This raises the idea that maintenance of the healthy gut microbiota and prevention of gut microbial dysbiosis in COVID-19 patients might avoid the increased cytokine storm, which in turn might reduce the mortality rate. It has been shown that the modulation of the gut microbiota is an effective strategy to strengthen immunity and might be a possible treatment for individuals with viral infections. Currently, there is no clinical data considering the impact of the modulation of the gut microbiota on the treatment of COVID-19. We hypothesize that targeting the gut microbiota might be a novel therapeutic approach or at least a supportive therapy. In the present review article, we described the interaction between SARS-CoV-2 and gut microbiota dysbiosis through two possible mechanisms, including aberrant immune activation and aberrant mammalian target of rapamycin (mTOR) activation. Further, the disruption of the gastrointestinal reninangiotensin system (GI RAS), dysregulation of the coagulation and fibrinolytic systems, and the activity of human serine proteases in COVID-19 pathogenesis were addressed. We also provided possible strategies to restore all the discussed aspects via gut microbiota modulation.

Introduction of a novel 18S rDNA gene arrangement along with distinct ITS region in the saline water microalga Dunaliella.

Comparison of 18S rDNA gene sequences is a very promising method for identification and classification of living organisms. Molecular identification and discrimination of different Dunaliella species were carried out based on the size of 18S rDNA gene and, number and position of introns in the gene. Three types of 18S rDNA structure have already been reported: the gene with a size of ~1770 bp lacking any intron, with a size of ~2170 bp consisting one intron near 5' terminus, and with a size of ~2570 bp harbouring two introns near 5' and 3' termini. Hereby, we report a new 18S rDNA gene arrangement in terms of intron localization and nucleotide sequence in a Dunaliella isolated from Iranian salt lakes (ABRIINW-M1/2). PCR amplification with genus-specific primers resulted in production of a ~2170 bp DNA band, which is similar to that of D. salina 18S rDNA gene containing only one intron near 5' terminus. Whilst, sequence composition of the gene revealed the lack of any intron near 5' terminus in our isolate. Furthermore, another alteration was observed due to the presence of a 440 bp DNA fragment near 3' terminus. Accordingly, 18S rDNA gene of the isolate is clearly different from those of D. salina and any other Dunaliella species reported so far. Moreover, analysis of ITS region sequence showed the diversity of this region compared to the previously reported species. 18S rDNA and ITS sequences of our isolate were submitted with accesion numbers of EU678868 and EU927373 in NCBI database, respectively. The optimum growth rate of this isolate occured at the salinity level of 1 M NaCl. The maximum carotenoid content under stress condition of intense light (400 mumol photon m-2 s-1), high salinity (4 M NaCl) and deficiency of nitrate and phosphate nutritions reached to 240 ng/cell after 15 days.