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Female Aedes aegypti mosquitoes are deadly vectors of arboviral pathogens and breed in containers of freshwater associated with human habitation. Because high salinity is lethal to offspring, correctly evaluating water purity is a crucial parenting decision. We found that the DEG/ENaC channel ppk301 and sensory neurons expressing ppk301 control egg-laying initiation and choice in Ae. aegypti. Using calcium imaging, we found that ppk301-expressing cells show ppk301-dependent responses to water but, unexpectedly, also respond to salt in a ppk301-independent fashion. This suggests that ppk301 is instructive for egg-laying at low-salt concentrations, but that a ppk301-independent pathway is responsible for inhibiting egg-laying at high-salt concentrations. Water is a key resource for insect survival and understanding how mosquitoes interact with water to control different behaviors is an opportunity to study the evolution of chemosensory systems.

The intestinal immune system has the challenging task of tolerating foreign nutrients and the commensal microbiome, while excluding or eliminating ingested pathogens. Failure of this balance leads to conditions such as inflammatory bowel diseases, food allergies and invasive gastrointestinal infections(1). Multiple immune mechanisms are therefore in place to maintain tissue integrity, including balanced generation of effector T (T-H) cells and FOXP3(+) regulatory T (pT(reg)) cells, which mediate resistance to pathogens and regulate excessive immune activation, respectively(1-4). The gut-draining lymph nodes (gLNs) are key sites for orchestrating adaptive immunity to luminal perturbations(5-7). However, it is unclear how they simultaneously support tolerogenic and inflammatory reactions. Here we show that gLNs are immunologically specific to the functional gut segment that they drain. Stromal and dendritic cell gene signatures and polarization of T cells against the same luminal antigen differ between gLNs, with the proximal small intestine-draining gLNs preferentially giving rise to tolerogenic responses and the distal gLNs to pro-inflammatory T cell responses. This segregation permitted the targeting of distal gLNs for vaccination and the maintenance of duodenal pTreg cell induction during colonic infection. Conversely, the compartmentalized dichotomy was perturbed by surgical removal of select distal gLNs and duodenal infection, with effects on both lymphoid organ and tissue immune responses. Our findings reveal that the conflict between tolerogenic and inflammatory intestinal responses is in part resolved by discrete gLN drainage, and encourage antigen targeting to specific gut segments for therapeutic immune modulation.

Ribosome biogenesis is a canonical hallmark of cell growth and proliferation. Here we show that execution of Epithelial-to-Mesenchymal Transition (EMT), a migratory cellular program associated with development and tumor metastasis, is fueled by upregulation of ribosome biogenesis during G1/S arrest. This unexpected EMT feature is independent of species and initiating signal, and is accompanied by release of the repressive nucleolar chromatin remodeling complex (NoRC) from rDNA, together with recruitment of the EMT-driving transcription factor Snai1 (Snail1), RNA Polymerase I (Pol I) and the Upstream Binding Factor (UBF). EMT-associated ribosome biogenesis is also coincident with increased nucleolar recruitment of Rictor, an essential component of the EMT-promoting mammalian target of rapamycin complex 2 (mTORC2). Inhibition of rRNA synthesis in vivo differentiates primary tumors to a benign, Estrogen Receptor-alpha (ER alpha) positive, Rictor-negative phenotype and reduces metastasis. These findings implicate the EMT-associated ribosome biogenesis program with cellular plasticity, de-differentiation, cancer progression and metastatic disease.

Cyclic GMP-AMP synthase (cGAS) is the primary sensor for aberrant intracellular dsDNA producing the cyclic dinucleotide cGAMP, a second messenger initiating cytokine production in subsets of myeloid lineage cell types. Therefore, inhibition of the enzyme cGAS may act anti-inflammatory. Here we report the discovery of human-cGAS-specific small-molecule inhibitors by high-throughput screening and the targeted medicinal chemistry optimization for two molecular scaffolds. Lead compounds from one scaffold co-crystallize with human cGAS and occupy the ATP- and GTP-binding active site. The specificity and potency of these drug candidates is further documented in human myeloid cells including primary macrophages. These novel cGAS inhibitors with cell-based activity will serve as probes into cGAS-dependent innate immune pathways and warrant future pharmacological studies for treatment of cGAS-dependent inflammatory diseases.

A longitudinal study by Davis et al. followed the evolution of antibody responses in four survivors of the 2014 Ebola outbreak treated in the United States and provides insight into the emergence of neutralizing antibodies long after convalescence.

Streptococcus pseudopneumoniae is a close relative of the major human pathogen S. pneumoniae. It is increasingly associated with lower-respiratory-tract infections (LRTI) and a high prevalence of antimicrobial resistance (AMR). S. pseudopneumoniae is difficult to identify using traditional typing methods due to similarities with S. pneumoniae and other members of the mitis group (SMG). Using whole-genome sequencing of LRTI isolates and a comparative genomic approach, we found that a large number of pneumococcal virulence and colonization genes are present in the core S. pseudopneumoniae genome. We also reveal an impressive number of novel surface-exposed proteins encoded by the genome of this species. In addition, we propose a new and entirely specific molecular marker useful for the identification of S. pseudopneumoniae. Phylogenetic analyses of S. pseudopneumoniae show that specific clades are associated with allelic variants of core proteins. Resistance to tetracycline and macrolides, the two most common types of resistance, were found to be encoded by Tn916-like integrating conjugative elements and Mega-2. Overall, we found a tight association of genotypic determinants of AMR and phenotypic AMR with a specific lineage of S. pseudopneumoniae. Taken together, our results shed light on the distribution in S. pseudopneumoniae of genes known to be important during invasive disease and colonization and provide insight into features that could contribute to virulence, colonization, and adaptation. IMPORTANCE S. pseudopneumoniae is an overlooked pathogen emerging as the causative agent of lower-respiratory-tract infections and associated with chronic obstructive pulmonary disease (COPD) and exacerbation of COPD. However, much remains unknown on its clinical importance and epidemiology, mainly due to the lack of specific markers to distinguish it from S. pneumoniae. Here, we provide a new molecular marker entirely specific for S. pseudopneumoniae and offer a comprehensive view of the virulence and colonization genes found in this species. Finally, our results pave the way for further studies aiming at understanding the pathogenesis and epidemiology of S. pseudopneumoniae.

Stress and the circadian systems play a major role in an organism's adaptation to environmental changes. The adaptive value of the stress system is reactive while that of the circadian system is predictive. Dysfunctions in these two systems may account for many clinically relevant disorders. Despite the evidence that interindividual differences in stress sensitivity and in the functioning of the circadian system are related, there is limited integrated research on these topics. Moreover, sex differences in these systems are poorly investigated. We used the perinatal stress (PRS) rat model, a well-characterized model of maladaptive programming of reactive and predictive adaptation, to monitor the running wheel behavior in male and female adult PRS rats, under a normal light/dark cycle as well as in response to a chronobiological stressor (6-h phase advance/shift). We then analyzed across different time points the expression of genes involved in circadian clocks, stress response, signaling, and glucose metabolism regulation in the suprachiasmatic nucleus (SCN). In the unstressed control group, we found a sex-specific profile that was either enhanced or inverted by PRS. Also, PRS disrupted circadian wheel-running behavior by inducing a phase advance in the activity of males and hypoactivity in females and increased vulnerability to chronobiological stress in both sexes. We also observed oscillations of several genes in the SCN of the unstressed group in both sexes. PRS affected males to greater extent than females, with PRS males displaying a pattern similar to unstressed females. Altogether, our findings provide evidence for a specific profile of dysmasculinization induced by PRS at the behavioral and molecular level, thus advocating the necessity to include sex as a biological variable to study the set-up of circadian system in animal models.

Lytic bacteriophages (or phages) drive bacterial mortality by elaborating exquisite abilities to bind, breach, and destroy bacterial cell membranes and subjugate critical bacterial cell functions. These antimicrobial activities make phages ideal candidates to serve as, or provide sources of, biological control measures for bacterial pathogens. In this study, we isolated the Myoviridae phage vB_BanS_Bcp1 (here referred to as Bcp1) from landfill soil, using a Bacillus anthracis host. The antimicrobial activities of both Bcp1 and its encoded endolysin, PlyB, were examined across different B. cereus sensu lato group species, including B. cereus sensu stricto, Bacillus thuringiensis, and Bacillus anthracis, with pathogenic potential in humans and multiple different uses in biotechnological applications. The Bcp1 phage infected only a subset (11 to 66%) of each B. cereus sensu lato species group tested. In contrast, functional analysis of purified PlyB revealed a potent bacteriolytic activity against all B. cereus sensu lato isolates tested (n = 79). plyB was, furthermore, active across broad temperature, pH, and salt ranges, refractory to the development of resistance, bactericidal as a single agent, and synergistic with a second endolysin, PlyG. To confirm the potential for PlyB as an antimicrobial agent, we demonstrated the efficacy of a single intravenous treatment with PlyB alone or combination with PlyG in a murine model of lethal B. anthracis infection. Overall, our findings show exciting potential for the Bcp1 bacteriophage and the PlyB endolysin as potential new additions to the antimicrobial armamentarium. IMPORTANCE Organisms of the Bacillus cereus sensu lato lineage are ubiquitous in the environment and are responsible for toxin-mediated infections ranging from severe food poisoning (B. cereus sensu stricto) to anthrax (Bacillus anthracis). The increasing incidence of many of these infections, combined with the specter of antibiotic resistance, has created a need for novel antimicrobials with potent activity, including bacteriophages (or phages) and phage-encoded products (i.e., endolysins). In this study, we describe a broadly infective phage, Bcp1, and its encoded endolysin, PlyB, which exhibited a rapidly bacteriolytic effect against all B. cereus sensu lato isolates tested with no evidence of evolving resistance. Importantly, PlyB was highly efficacious in a mouse model of lethal bacteremia with B. anthracis. Both the Bcp1 phage and the PlyB endolysin represent novel mechanisms of action compared to antibiotics, with potential applications to address the evolving problem of antimicrobial resistance.

Humans use a family of more than 400 olfactory receptors (ORs) to detect odors, but there is currently no model that can predict olfactory perception from receptor activity patterns. Genetic variation in human ORs is abundant and alters receptor function, allowing us to examine the relationship between receptor function and perception. We sequenced the OR repertoire in 332 individuals and examined how genetic variation affected 276 olfactory phenotypes, including the perceived intensity and pleasantness of 68 odorants at two concentrations, detection thresholds of three odorants, and general olfactory acuity. Genetic variation in a single OR was frequently associated with changes in odorant perception, and we validated 10 cases in which in vitro OR function correlated with in vivo odorant perception using a functional assay. In 8 of these 10 cases, reduced receptor function was associated with reduced intensity perception. In addition, we used participant genotypes to quantify genetic ancestry and found that, in combination with single OR genotype, age, and gender, we can explain between 10% and 20% of the perceptual variation in 15 olfactory phenotypes, highlighting the importance of single OR genotype, ancestry, and demographic factors in the variation of olfactory perception.

The human genetic basis of tuberculosis (TB) has long remained elusive. We recently reported a high level of enrichment in homozygosity for the common TYK2 P1104A variant in a heterogeneous cohort of patients with TB from non-European countries in which TB is endemic. This variant is homozygous in similar to 1/600 Europeans and similar to 1/5,000 people from other countries outside East Asia and sub-Saharan Africa. We report a study of this variant in the UK Biobank cohort. The frequency of P1104A homozygotes was much higher in patients with TB (6/620, 1%) than in controls (228/114,473, 0.2%), with an odds ratio (OR) adjusted for ancestry of 5.0 [95% confidence interval (CI): 1.96-10.31, P = 2 x 10(-3)]. Conversely, we did not observe enrichment for P1104A heterozygosity, or for TYK2 I684S or V362F homozygosity or heterozygosity. Moreover, it is unlikely that more than 10% of controls were infected with Mycobacterium tuberculosis, as 97% were of European genetic ancestry, born between 1939 and 1970, and resided in the United Kingdom. Had all of them been infected, the OR for developing TB upon infection would be higher. These findings suggest that homozygosity for TYK2 P1104A may account for similar to 1% of TB cases in Europeans.