Over the past 16 years, three coronaviruses (CoVs), severe acute respiratory syndrome CoV (SARS-CoV) in 2002, Middle East respiratory syndrome CoV (MERS-CoV) in 2012 and 2015, and SARS-CoV-2 in 2020, have been causing severe and fatal human epidemics. The unpredictability of coronavirus disease-19 (COVID-19) poses a major burden on health care and economic systems across the world. This is caused by the paucity of in-depth knowledge of the risk factors for severe COVID-19, insufficient diagnostic tools for the detection of SARS-CoV-2, as well as the absence of specific and effective drug treatments. While protective humoral and cellular immune responses are usually mounted against these betacoronaviruses, immune responses to SARS-CoV2 sometimes derail towards inflammatory tissue damage, leading to rapid admissions to intensive care units. The lack of knowledge on mechanisms that tilt the balance between these two opposite outcomes poses major threats to many ongoing clinical trials dealing with immunostimulatory or immunoregulatory therapeutics. This review will discuss innate and cognate immune responses underlying protective or deleterious immune reactions against these pathogenic coronaviruses.
Polyphasic analysis of four new Vibrio isolates originating from the haemolymph of diseased cultured oysters is described. The new isolates were closely related to Vibrio splendidus, having 98 % 16S rRNA gene sequence similarity. Phylogenetic analysis based on DNA gyrase subunit B (gyrB), RNA polymerase s 70 factor (rpoD), replication origin-binding protein (rctB) and transmembrane regulatory protein (toxR) genes, fluorescent amplified fragment length polymorphism and DNA-DNA hybridization experiments clearly showed that the new isolates form a tight genomic group that is different from the currently known Vibrio species. It is proposed that these new isolates should be accommodated in a novel species, Vibrio gigantis sp. nov. Phenotypic features that differentiate V. gigantis from other known Vibrio species include arginine dihydrolase, gelatinase and b-galactosidase activities, NO 2 production, growth at 35 6C, and utilization of sucrose, melibiose, amygdalin, glycerol, galactose, starch and glycogen. The type strain is LGP 13 T (=LMG 22741 T =CIP 108656 T ).
The Seine-Morée wastewater treatment plant (SM_WWTP), with a capacity of 100,000 populationequivalents, was fed with raw domestic wastewater during all of its start-up phase. its microbiome resulted from the spontaneous evolution of wastewater-borne microorganisms. this rare opportunity allowed us to analyze the sequential microbiota colonization and implantation follow up during the start-up phase of this WWTP by means of regular sampling carried out over 8 months until the establishment of a stable and functional ecosystem. During the study, biological nitrificationdenitrification and dephosphatation occurred 68 days after the start-up of the WWTP, followed by flocs decantation 91 days later. High throughput sequencing of 18S and 16S rRNA genes was performed using Illumina's MiSeq and PGM Ion Torrent platforms respectively, generating 584,647 16S and 521,031 18S high-quality sequence rDNA reads. Analyses of 16S and 18S rDNA datasets show three colonization phases occurring concomitantly with nitrification, dephosphatation and floc development processes. Thus, we could define three microbiota profiles that sequentially colonized the SM_WWtp: the early colonizers, the late colonizers and the continuous spectrum population. Shannon and inverse Simpson diversity indices indicate that the highest microbiota diversity was reached at days 133 and 82 for prokaryotes and eukaryotes respectively; after that, the structure and complexity of the wastewater microbiome reached its functional stability. this study demonstrates that physicochemical parameters and microbial metabolic interactions are the main forces shaping microbial community structure, gradually building up and maintaining a functionally stable microbial ecosystem. The wastewater treatment process is based on the use of sludge microbial populations to treat domestic and industrial pollutants. These populations constitute a complex ecosystem with biomass concentration approximating 2-10 g L −11 , with the majority aggregated into structures called flocs. The floc structure represents a protection strategy for microorganisms against predation as well as toxic chemicals, meanwhile allowing efficient uptake of nutrients. These flocs may contain up to 10 10 prokaryotes mL −1 and 10 6 micro-eukaryotes mL −1. Molecular approaches reveal that they often share persistent prokaryotic and eukaryotic core species stably retained over time, including among others, members of the Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria phyla 2-4. However, in comparison with prokaryotes, micro-eukaryotic diversity has benefited relatively little from modern molecular tools and high throughput sequencing technologies. The few sequencing-based analyses
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