Together throughout the year: seasonal patterns of bacterial and eukaryotic microbial communities in a macrotidal estuary.

Background: Estuaries are complex ecosystems linking river and marine environments, where microorganisms play a key role in maintaining ecosystem functions. In the present study, we investigated monthly 8 sites at two depth layers and over a one-year period the bacterial and eukaryotic community dynamics along the Seine macrotidal estuary (Normandy, France). To date, the taxonomy of the microbial diversity present in this anthropized estuary remains elusive and the drivers of the microbial community structure are still unknown.

A Novel Lineage of Endosymbiotic Actinomycetales: Genome Reduction and Acquisition of New Functions in Bifidobacteriaceae Associated With Termite Gut Flagellates.

Cellulolytic flagellates are essential for the symbiotic digestion of lignocellulose in the gut of lower termites. Most species are associated with host-specific consortia of bacterial symbionts from various phyla. 16S rRNA-based diversity studies and taxon-specific fluorescence in situ hybridization revealed a termite-specific clade of Actinomycetales that colonise the cytoplasm of Trichonympha spp.

Iron fortification modifies the microbial community structure and metabolome of a model surface-ripened cheese.

Iron is a vital micronutrient for nearly all microorganisms, serving as a co-factor in critical metabolic pathways. However, cheese is an iron-restricted environment. Furthermore, it has been demonstrated that iron represents a growth-limiting factor for many microorganisms involved in cheese ripening and that this element is central to many microbial interactions occurring in this ecosystem.

Genome reduction in novel, obligately methyl-reducing Methanosarcinales isolated from arthropod guts (Methanolapillus gen. nov. and Methanimicrococcus).

Recent metagenomic studies have identified numerous lineages of hydrogen-dependent, obligately methyl-reducing methanogens. Yet, only a few representatives have been isolated in pure culture. Here, we describe six new species with this capability in the family Methanosarcinaceae (order Methanosarcinales), which makes up a substantial fraction of the methanogenic community in arthropod guts.

Genome reduction and horizontal gene transfer in the evolution of Endomicrobia-rise and fall of an intracellular symbiosis with termite gut flagellates.

Bacterial endosymbionts of eukaryotic hosts typically experience massive genome reduction, but the underlying evolutionary processes are often obscured by the lack of free-living relatives. Endomicrobia, a family-level lineage of host-associated bacteria in the phylum that comprises both free-living representatives and endosymbionts of termite gut flagellates, are an excellent model to study evolution of intracellular symbionts. We reconstructed 67 metagenome-assembled genomes (MAGs) of among more than 1,700 MAGs from the gut microbiota of a wide range of termites.

Diversity and taxonomic revision of methanogens and other archaea in the intestinal tract of terrestrial arthropods.

Methane emission by terrestrial invertebrates is restricted to millipedes, termites, cockroaches, and scarab beetles. The arthropod-associated archaea known to date belong to the orders , and , and in a few cases also to non-methanogenic and . However, all major host groups are severely undersampled, and the taxonomy of existing lineages is not well developed.

Implication of tau propagation on neurodegeneration in Alzheimer's disease.

Propagation of tau fibrils correlate closely with neurodegeneration and memory deficits seen during the progression of Alzheimer's disease (AD). Although it is not well-established what drives or attenuates tau spreading, new studies on human brain using positron emission tomography (PET) have shed light on how tau phosphorylation, genetic factors, and the initial epicenter of tau accumulation influence tau accumulation and propagation throughout the brain. Here, we review the latest PET studies performed across the entire AD continuum looking at the impact of amyloid load on tau pathology.

Impact of non-neuronal cells in Alzheimer's disease from a single-nucleus profiling perspective.

The role of non-neuronal cells has been relatively overlooked in Alzheimer's disease (AD) neuropathogenesis compared to neuronal cells since the first characterization of the disease. Genome wide-association studies (GWAS) performed in the last few decades have greatly contributed to highlighting the critical impact of non-neuronal cells in AD by uncovering major genetic risk factors that are found largely in these cell types. The recent development of single cell or single nucleus technologies has revolutionized the way we interrogate the transcriptomic and epigenetic profiles of neurons, microglia, astrocytes, oligodendrocytes, pericytes, and endothelial cells simultaneously in the same sample and in an individual manner.

: a simple, efficient, flexible and scalable workflow to reconstruct prokaryotic genomes from metagenomes.

Over the last decade, we have observed in microbial ecology a transition from gene-centric to genome-centric analyses. Indeed, the advent of metagenomics combined with binning methods, single-cell genome sequencing as well as high-throughput cultivation methods have contributed to the continuing and exponential increase of available prokaryotic genomes, which in turn has favored the exploration of microbial metabolisms. In the case of metagenomics, data processing, from raw reads to genome reconstruction, involves various steps and software which can represent a major technical obstacle.

Temporal pesticide dynamics alter specific eukaryotic taxa in a coastal transition zone.

Land use change and anthropogenic forcing can drastically alter the rates and patterns of sediment transport and modify biodiversity and ecosystem functions in coastal transition zones, such as the coastal ecosystems. Molecular studies of sediment extracted DNAs provide information on currently living organisms within the upper layers or buried from various periods of time, but might also provide knowledge on species dynamics, replacement and turnover. In this study, we evaluated the eukaryotic communities of a marine core that present a shift in soil erosion that was linked to glyphosate usage and correlated to chlordecone resurgence since 2000.

Deep Tissue Penetration of Bottle-Brush Polymers via Cell Capture Evasion and Fast Diffusion.

Drug nanocarriers (NCs) capable of crossing the vascular endothelium and deeply penetrating into dense tissues of the CNS could potentially transform the management of neurological diseases. In the present study, we investigated the interaction of bottle-brush (BB) polymers with different biological barriers and and compared it to nanospheres of similar composition. internalization and permeability assays revealed that BB polymers are not internalized by brain-associated cell lines and translocate much faster across a blood-brain barrier model compared to nanospheres of similar hydrodynamic diameter.

Changes in Bacterial Community Structure Across the Different Life Stages of Black Soldier Fly (Hermetia illucens).

The digestive capacity of organic compounds by the black soldier fly (BSF, Hermetia illucens, Diptera: Stratiomyidae, Linnaeus, 1758) is known to rely on complex larva-microbiota interactions. Although insect development is known to be a driver of changes of bacterial communities, the fluctuations along BSF life cycle in terms of composition and diversity of bacterial communities are still unknown. In this work, we used a metabarcoding approach to explore the differences in bacterial diversity along all four BSF developmental stages: eggs, larvae, pupae, and adult.

Comparative Analysis of gen. nov., sp. nov. and gen. nov., comb. nov. () Reveals the Importance of Interspecies Hydrogen Transfer in the Energy Metabolism of Spirochetes.

Most members of the family () are associated with vertebrate hosts. However, a diverse clade of uncultured, putatively free-living treponemes comprising several genus-level lineages is present in other anoxic environments. The only cultivated representative to date is Treponema zuelzerae, isolated from freshwater mud.

The functional evolution of termite gut microbiota.

Background: Termites primarily feed on lignocellulose or soil in association with specific gut microbes. The functioning of the termite gut microbiota is partly understood in a handful of wood-feeding pest species but remains largely unknown in other taxa. We intend to fill this gap and provide a global understanding of the functional evolution of termite gut microbiota.

Differentially Shapes the Microbiota Composition and Diversity at Coastal Tide Sites and Inland Storage Sites on Caribbean Islands.

Rafts of drifting pelagic that are circulating across the Atlantic Ocean are complex ecosystems composed of a large number of associated species. Upon massive stranding, they lead to various socio-environmental issues including the inflow of contaminants and human health concerns. In this study, we used metabarcoding approaches to examine the differences in both the eukaryotic- and prokaryotic-associated communities from present in two islands of the Lesser Antilles, namely Guadeloupe and Martinique.

Functional Diversity of the Litter-Associated Fungi from an Oxalate-Carbonate Pathway Ecosystem in Madagascar.

The oxalate-carbonate pathway (OCP) is a biogeochemical process linking oxalate oxidation and carbonate precipitation. Currently, this pathway is described as a tripartite association involving oxalogenic plants, oxalogenic fungi, and oxalotrophic bacteria. While the OCP has recently received increasing interest given its potential for capturing carbon in soils, there are still many unknowns, especially regarding the taxonomic and functional diversity of the fungi involved in this pathway.

Characterization and phylogenomic analysis of Breznakiella homolactica gen. nov. sp. nov. indicate that termite gut treponemes evolved from non-acetogenic spirochetes in cockroaches.

Spirochetes of the genus Treponema are surprisingly abundant in termite guts, where they play an important role in reductive acetogenesis. Although they occur in all termites investigated, their evolutionary origin is obscure. Here, we isolated the first representative of 'termite gut treponemes' from cockroaches, the closest relatives of termites.

Cerebral Apolipoprotein D Exits the Brain and Accumulates in Peripheral Tissues.

Apolipoprotein D (ApoD) is a secreted lipocalin associated with neuroprotection and lipid metabolism. In rodent, the bulk of its expression occurs in the central nervous system. Despite this, ApoD has profound effects in peripheral tissues, indicating that neural ApoD may reach peripheral organs.

Polyphenol-Peptide Interactions in Mitigation of Alzheimer's Disease: Role of Biosurface-Induced Aggregation.

Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder, responsible for nearly two-thirds of all dementia cases. In this review, we report the potential AD treatment strategies focusing on natural polyphenol molecules (green chemistry) and more specifically on the inhibition of polyphenol-induced amyloid aggregation/disaggregation pathways: in bulk and on biosurfaces. We discuss how these pathways can potentially alter the structure at the early stages of AD, hence delaying the aggregation of amyloid-β (Aβ) and tau.

Glutathione: An Old and Small Molecule with Great Functions and New Applications in the Brain and in Alzheimer's Disease.

Glutathione (GSH) represents the most abundant and the main antioxidant in the body with important functions in the brain related to Alzheimer's disease (AD). Oxidative stress is one of the central mechanisms in AD. We and others have demonstrated the alteration of GSH levels in the AD brain, its important role in the detoxification of advanced glycation end-products and of acrolein, a by-product of lipid peroxidation.

Metabolic Potential for Reductive Acetogenesis and a Novel Energy-Converting [NiFe] Hydrogenase in From Termite Guts - A Genome-Centric Analysis.

Symbiotic digestion of lignocellulose in the hindgut of higher termites is mediated by a diverse assemblage of bacteria and archaea. During a large-scale metagenomic study, we reconstructed 15 metagenome-assembled genomes of that represent two distinct lineages in subgroup 6 (formerly MCG-6) unique to termite guts. One lineage (TB2; Termitimicrobium) encodes all enzymes required for reductive acetogenesis from CO via an archaeal variant of the Wood-Ljungdahl pathway, involving tetrahydromethanopterin as C carrier and an (ADP-forming) acetyl-CoA synthase.

Long rDNA amplicon sequencing of insect-infecting nephridiophagids reveals their affiliation to the Chytridiomycota and a potential to switch between hosts.

Nephridiophagids are unicellular eukaryotes that parasitize the Malpighian tubules of numerous insects. Their life cycle comprises multinucleate vegetative plasmodia that divide into oligonucleate and uninucleate cells, and sporogonial plasmodia that form uninucleate spores. Nephridiophagids are poor in morphological characteristics, and although they have been tentatively identified as early-branching fungi based on the SSU rRNA gene sequences of three species, their exact position within the fungal tree of live remained unclear.