Highlights d Three weeks after the first BNT162b2 dose, weak neutralizing antibodies are elicited d These antibodies have robust Fc-mediated effector functions d Vaccination of individuals previously infected boosts humoral and cellular responses d Strong correlations between T helper cell and humoral responses are observed

SubtiList is the reference database dedicated to the genome of Bacillus subtilis 168, the paradigm of Gram-positive endospore-forming bacteria. Developed in the framework of the B.subtilis genome project, SubtiList provides a curated dataset of DNA and protein sequences, combined with the relevant annotations and functional assignments. Information about gene functions and products is continuously updated by linking relevant bibliographic references. Recently, sequence corrections arising from both systematic verifications and submissions by individual scientists were included in the reference genome sequence. SubtiList is based on a generic relational data schema and a World Wide Web interface developed for the handling of bacterial genomes, called GenoList. The World Wide Web interface was designed to allow users to easily browse through genome data and retrieve information according to common biological queries. SubtiList also provides more elaborate tools, such as pattern searching, which are tightly connected to the overall browsing system. SubtiList is accessible at http://genolist.pasteur.fr/SubtiList/. Similar bacterial databases are accessible at http://genolist.pasteur.fr/.

Gene expression analysis by microarray assay revealed that when exposed to stress, Entamoeba histolytica exhibits a specific heat shock response, together with a dramatic overall reduction in gene transcription as well as differential allelic expression of key genes participating in virulence, such as the galactose/N-acetylgalactosamine (Gal/GalNAc) lectin.Amoebiasis is a disease caused by the enteric protozoan parasite Entamoeba histolytica. Following invasion of human tissue by E. histolytica, the two major clinical manifestations are hemorrhagic colitis and liver abscesses (18). For infection to succeed, invading trophozoites must produce an adaptive response that ensures their protection against the host response and survival. Hence, E. histolytica proteins whose production is triggered or modulated by environmental stress are of great interest, since characterization of these species should help us understand the mechanisms which sustain pathogenesis and could lead to new treatments for amoebiasis.Microbial pathogens have evolved a number of strategies for protecting themselves from their hosts. One of these is the so-called heat shock response, which is elicited by a sudden increase in ambient temperature (13) and induces the synthesis of a limited set of proteins (called heat shock proteins [HSPs] or molecular chaperones). Homologues of known HSPs have been identified and partially characterized in E. histolytica (1,11). With the aim of determining gene expression changes during E. histolytica's adaptive response during infection, we developed an oligonucleotidebased microarray with transcript information randomly obtained from a cultured virulent strain of the pathogen. Array analysis revealed that gene transcription in E. histolytica exposed to heat shock is dramatically reduced, since 471 of 1,131 unique genes were down regulated, whereas specific HSP-encoding genes were up regulated. In conjunction with real-time PCR results, these genetic information data reveal for the first time a very interesting differential allelic expression of key genes participating in virulence, such as the immunodominant antigen Gal/GalNAc lectin, certain cysteine proteinases, and the so-called 20-kDa antigen.The aims of this study were (i) to establish a highly discriminating method for monitoring gene expression changes in E. histolytica and (ii) to determine the mRNA expression profile of E. histolytica cells growing in a drastically modified environment. We decided to construct an oligonucleotide-based microarray, using information obtained directly from sequence analysis of E. histolytica transcripts, a strategy that is generally thought to overcome problems due to gene redundancy and the presence of introns. A cDNA library of the virulent E. histolytica strain HM-1:IMSS and a liver-specific cDNA subtraction library were prepared and sequenced. The bioinformatic analysis of sequenced clones enabled us to define 1,300 bona fide transcripts, all from parasites growing in vitro and enriched with randomly chosen transcrip...

Continuous emergence of SARS-CoV-2 variants of concern (VOC) is fueling the COVID-19 pandemic. Omicron (B.1.1.529) rapidly spread worldwide. The large number of mutations in its Spike raise concerns about a major antigenic drift that could significantly decrease vaccine efficacy and infection-induced immunity. A long interval between BNT162b2 mRNA doses elicit antibodies that efficiently recognize Spikes from different VOCs. Here we evaluate the recognition of Omicron Spike by plasma from a cohort of SARS-CoV-2 naïve and previously infected individuals that received their BNT162b2 mRNA vaccine 16-weeks apart. Omicron Spike is recognized less efficiently than D614G, Alpha, Beta, Gamma and Delta Spikes. We compare to plasma activity from participants receiving a short (4-weeks) interval regimen. Plasma from individuals of the long interval cohort recognize and neutralize better the Omicron Spike compared to those that received a short interval. Whether this difference confers any clinical benefit against Omicron remains unknown.

The seasonal nature of outbreaks of respiratory viral infections with increased transmission during low temperatures has been well established. Accordingly, temperature has been suggested to play a role on the viability and transmissibility of SARS-CoV-2, the virus responsible for the COVID-19 pandemic. The receptor binding domain (RBD) of the Spike glycoprotein is known to bind to its host receptor angiotensin-converting enzyme 2 (ACE2) to initiate viral fusion. Using biochemical, biophysical and functional assays to dissect the effect of temperature on the receptor-Spike interaction, we observed a significant and stepwise increase in RBD-ACE2 affinity at low temperatures, resulting in slower dissociation kinetics. This translated into enhanced interaction of the full Spike glycoprotein with the ACE2 receptor and higher viral attachment at low temperatures. Interestingly, the RBD N501Y mutation, present in emerging variants of concern (VOCs) that are fueling the pandemic worldwide (including the B.1.1.7 (α) lineage), bypassed this requirement. This data suggests that the acquisition of N501Y reflects an adaptation to warmer climates, a hypothesis that remains to be tested.

The standard dosing of the Pfizer/BioNTech BNT162b2 mRNA vaccine validated in clinical trials includes two doses administered three weeks apart. While the decision by some public health authorities to space the doses because of limiting supply has raised concerns about vaccine efficacy, data indicate that a single dose is up to 90% effective starting 14 days after its administration. We analyzed humoral and T cells responses three weeks after a single dose of this mRNA vaccine. Despite the proven efficacy of the vaccine at this time point, no neutralizing activity were elicited in SARS-CoV-2 naïve individuals. However, we detected strong anti-receptor binding domain (RBD) and Spike antibodies with Fc-mediated effector functions and cellular responses dominated by the CD4+ T cell component. A single dose of this mRNA vaccine to individuals previously infected by SARS-CoV-2 boosted all humoral and T cell responses measured, with strong correlations between T helper and antibody immunity. Neutralizing responses were increased in both potency and breadth, with distinctive capacity to neutralize emerging variant strains. Our results highlight the importance of vaccinating uninfected and previously-infected individuals and shed new light into the potential role of Fc-mediated effector functions and T cell responses in vaccine efficacy. They also provide support to spacing the doses of two-vaccine regimens to vaccinate a larger pool of the population in the context of vaccine scarcity against SARS-CoV-2.

Gene structure and expression in diplonemid mitochondria are unparalleled. Genes are fragmented in pieces (modules) that are separately transcribed, followed by the joining of module transcripts to contiguous RNAs. Some instances of unique uridine insertion RNA editing at module boundaries were noted, but the extent and potential occurrence of other editing types remained unknown. Comparative analysis of deep transcriptome and genome data from Diplonema papillatum mitochondria reveals ∼220 post-transcriptional insertions of uridines, but no insertions of other nucleotides nor deletions. In addition, we detect in total 114 substitutions of cytosine by uridine and adenosine by inosine, amassed into unusually compact clusters. Inosines in transcripts were confirmed experimentally. This is the first report of adenosine-to-inosine editing of mRNAs and ribosomal RNAs in mitochondria. In mRNAs, editing causes mostly amino-acid additions and non-synonymous substitutions; in ribosomal RNAs, it permits formation of canonical secondary structures. Two extensively edited transcripts were compared across four diplonemids. The pattern of uridine-insertion editing is strictly conserved, whereas substitution editing has diverged dramatically, but still rendering diplonemid proteins more similar to other eukaryotic orthologs. We posit that RNA editing not only compensates but also sustains, or even accelerates, ultra-rapid evolution of genome structure and sequence in diplonemid mitochondria.

Mitochondrial ribosomal RNAs (rRNAs) often display reduced size and deviant secondary structure, and sometimes are fragmented, as are their corresponding genes. Here we report a mitochondrial large subunit rRNA (mt-LSU rRNA) with unprecedented features. In the protist Diplonema, the rnl gene is split into two pieces (modules 1 and 2, 534- and 352-nt long) that are encoded by distinct mitochondrial chromosomes, yet the rRNA is continuous. To reconstruct the post-transcriptional maturation pathway of this rRNA, we have catalogued transcript intermediates by deep RNA sequencing and RT-PCR. Gene modules are transcribed separately. Subsequently, transcripts are end-processed, the module-1 transcript is polyuridylated and the module-2 transcript is polyadenylated. The two modules are joined via trans-splicing that retains at the junction ∼26 uridines, resulting in an extent of insertion RNA editing not observed before in any system. The A-tail of trans-spliced molecules is shorter than that of mono-module 2, and completely absent from mitoribosome-associated mt-LSU rRNA. We also characterize putative antisense transcripts. Antisense-mono-modules corroborate bi-directional transcription of chromosomes. Antisense-mt-LSU rRNA, if functional, has the potential of guiding concomitantly trans-splicing and editing of this rRNA. Together, these findings open a window on the investigation of complex regulatory networks that orchestrate multiple and biochemically diverse post-transcriptional events.