Pathobiont and symbiont contribute to microbiota homeostasis through Malpighian tubules-gut countercurrent flow in Bactrocera dorsalis.

Host-gut microbiota interactions are more complex than good or bad. Both gut symbiotic bacteria and pathobionts can provide essential functions to their host in one scenario and yet be detrimental to host health in another. So, these gut-dwelling bacteria must be tightly controlled to avoid harmful effects on the host.

Intestinal commensal bacteria promote Bactrocera dorsalis larval development through the vitamin B6 synthesis pathway.

Background: The gut microbiota can facilitate host growth under nutrient-constrained conditions. However, whether this effect is limited to certain bacterial species remains largely unclear, and the relevant underlying mechanisms remain to be thoroughly investigated.

Results: We found that the microbiota was required for Bactrocera dorsalis larval growth under poor dietary conditions.

Dietary L-Glu sensing by enteroendocrine cells adjusts food intake via modulating gut PYY/NPF secretion.

Amino acid availability is monitored by animals to adapt to their nutritional environment. Beyond gustatory receptors and systemic amino acid sensors, enteroendocrine cells (EECs) are believed to directly percept dietary amino acids and secrete regulatory peptides. However, the cellular machinery underlying amino acid-sensing by EECs and how EEC-derived hormones modulate feeding behavior remain elusive.

Duox activation in Drosophila Malpighian tubules stimulates intestinal epithelial renewal through a countercurrent flow.

The gut must perform a dual role of protecting the host against toxins and pathogens while harboring mutualistic microbiota. Previous studies suggested that the NADPH oxidase Duox contributes to intestinal homeostasis in Drosophila by producing reactive oxygen species (ROS) in the gut that stimulate epithelial renewal. We find instead that the ROS generated by Duox in the Malpighian tubules leads to the production of Upd3, which enters the gut and stimulates stem cell proliferation.

The conceptual foundations of innate immunity: Taking stock 30 years later.

While largely neglected over decades during which adaptive immunity captured most of the attention, innate immune mechanisms have now become central to our understanding of immunology. Innate immunity provides the first barrier to infection in vertebrates, and it is the sole mechanism of host defense in invertebrates and plants. Innate immunity also plays a critical role in maintaining homeostasis, shaping the microbiota, and in disease contexts such as cancer, neurodegeneration, metabolic syndromes, and aging.

A humoral stress response protects Drosophila tissues from antimicrobial peptides.

7An efficient immune system must provide protection against a broad range of pathogens without causing excessive collateral tissue damage. While immune effectors have been well characterized, we know less about the resilience mechanisms protecting the host from its own immune response. Antimicrobial peptides (AMPs) are small, cationic peptides that contribute to innate defenses by targeting negatively charged membranes of microbes.

Ecology-relevant bacteria drive the evolution of host antimicrobial peptides in .

Antimicrobial peptides are host-encoded immune effectors that combat pathogens and shape the microbiome in plants and animals. However, little is known about how the host antimicrobial peptide repertoire is adapted to its microbiome. Here, we characterized the function and evolution of the antimicrobial peptide family of Diptera.

The New Microbiology: an international lecture course on the island of Spetses.

In September 2022, an international summer course entitled 'The new microbiology' took place in Greece, on the island of Spetses. The organizers aimed to highlight the spectacular advances and the renaissance occurring in Microbiology, driven by developments in genomics, proteomics, imaging techniques, and bioinformatics. Combinations of these advances allow for single cell analyses, rapid and relatively inexpensive metagenomic and transcriptomic data analyses and comparisons, visualization of previously unsuspected mechanisms, and large-scale studies.

Influence of Timing of Maternal Pertussis Immunization on the Avidity of Transferred Antibodies in Term and Preterm Neonates.

The timing of maternal pertussis vaccination influences the titers of cord-blood anti-pertussis antibodies. Whether it affects their avidity is unknown. We demonstrate in 298 term and 72 preterm neonates that antibody avidity is independent of the timing of maternal vaccination, whether comparing second with third trimester or intervals before birth.

CERT1 mutations perturb human development by disrupting sphingolipid homeostasis.

Neural differentiation, synaptic transmission, and action potential propagation depend on membrane sphingolipids, whose metabolism is tightly regulated. Mutations in the ceramide transporter CERT (CERT1), which is involved in sphingolipid biosynthesis, are associated with intellectual disability, but the pathogenic mechanism remains obscure. Here, we characterize 31 individuals with de novo missense variants in CERT1.

Antimicrobial peptides do not directly contribute to aging in Drosophila, but improve lifespan by preventing dysbiosis.

Antimicrobial peptides (AMPs) are innate immune effectors first studied for their role in host defence. Recent studies have implicated these peptides in the clearance of aberrant cells and in neurodegenerative syndromes. In Drosophila, many AMPs are produced downstream of Toll and Imd NF-κB pathways upon infection.

Compartmentalized PGRP expression along the dipteran Bactrocera dorsalis gut forms a zone of protection for symbiotic bacteria.

All metazoan guts are subject to opposing pressures wherein the immune system must eliminate pathogens while tolerating the presence of symbiotic microbiota. The Imd pathway is an essential defense against invading pathogens in insect guts, but tolerance mechanisms are less understood. Here, we find PGRP-LB and PGRP-SB express mainly in the anterior and middle midgut in a similar pattern to symbiotic Enterobacteriaceae bacteria along the Bactrocera dorsalis gut.

Missed pertussis diagnosis during co-infection with Bordetella holmesii.

The purpose of this study is to identify predictive factors associated with missed diagnosis of B. pertussis-B. holmesii co-infection by assessing the analytical performance of a commercially available multiplexed PCR assay and by building a prediction model based on clinical signs and symptoms for detecting co-infections.

Disproportionate investment in Spiralin B production limits in-host growth and favors the vertical transmission of insect endosymbionts.

Insects frequently harbor endosymbionts, which are bacteria housed within host tissues. These associations are stably maintained over evolutionary timescales through vertical transmission of endosymbionts from host mothers to their offspring. Some endosymbionts manipulate host reproduction to facilitate spread within natural populations.

immunity: the gene encodes two host defence peptides with pathogen-specific roles.

Antimicrobial peptides (AMPs) are key to defence against infection in plants and animals. Use of AMP mutations in has now revealed that AMPs can additively or synergistically contribute to defence . However, these studies also revealed high specificity, wherein just one AMP contributes an outsized role in combatting a specific pathogen.

Repeated truncation of a modular antimicrobial peptide gene for neural context.

Antimicrobial peptides (AMPs) are host-encoded antibiotics that combat invading pathogens. These genes commonly encode multiple products as post-translationally cleaved polypeptides. Recent studies have highlighted roles for AMPs in neurological contexts suggesting functions for these defence molecules beyond infection.

Fitness of B-Cell Responses to SARS-CoV-2 WT and Variants Up to One Year After Mild COVID-19 - A Comprehensive Analysis.

Objective: To comprehensively evaluate SARS-CoV-2 specific B-cell and antibody responses up to one year after mild COVID-19.

Methods: In 31 mildly symptomatic COVID-19 participants SARS-CoV-2-specific plasmablasts and antigen-specific memory B cells were measured by ELISpot. Binding antibodies directed against the proteins spike (S), domain S1, and nucleocapsid (N) were estimated using rIFA, ELISA, and commercially available assays, and avidity measured using thiocyanate washout.

The wall-less bacterium builds a polymeric cytoskeleton composed of interacting MreB isoforms.

A rigid cell wall defines the morphology of most bacteria. MreB, a bacterial homologue of actin, plays a major role in coordinating cell wall biogenesis and defining cell shape. are wall-less bacteria that robustly grow with a characteristic helical shape.

The Drosophila Baramicin polypeptide gene protects against fungal infection.

The fruit fly Drosophila melanogaster combats microbial infection by producing a battery of effector peptides that are secreted into the haemolymph. Technical difficulties prevented the investigation of these short effector genes until the recent advent of the CRISPR/CAS era. As a consequence, many putative immune effectors remain to be formally described, and exactly how each of these effectors contribute to survival is not well characterized.

A secreted factor NimrodB4 promotes the elimination of apoptotic corpses by phagocytes in Drosophila.

Programmed cell death plays a fundamental role in development and tissue homeostasis. Professional and non-professional phagocytes achieve the proper recognition, uptake, and degradation of apoptotic cells, a process called efferocytosis. Failure in efferocytosis leads to autoimmune and neurodegenerative diseases.

SARS-CoV-2 infection as a trigger of humoral response against apolipoprotein A-1.

Background: Unravelling autoimmune targets triggered by SARS-CoV-2 infection may provide crucial insights into the physiopathology of the disease and foster the development of potential therapeutic candidate targets and prognostic tools. We aimed at determining (a) the association between anti-SARS-CoV-2 and anti-apoA-1 humoral response and (b) the degree of linear homology between SARS-CoV-2, apoA-1 and Toll-like receptor 2 (TLR2) epitopes.

Design: Bioinformatics modelling coupled with mimic peptides engineering and competition experiments were used to assess epitopes sequence homologies.

Antimicrobial Peptides and Lysozymes Regulate Gut Microbiota Composition and Abundance.

The gut microbiota affects the physiology and metabolism of animals and its alteration can lead to diseases such as gut dysplasia or metabolic disorders. Several reports have shown that the immune system plays an important role in shaping both bacterial community composition and abundance in , and that immune deficit, especially during aging, negatively affects microbiota richness and diversity. However, there has been little study at the effector level to demonstrate how immune pathways regulate the microbiota.