Adrian Alberto Pinto-Tomas

Microbial symbionts are increasingly recognized as key contributors to bee health, yet their roles in solitary bee brood cells remain largely unexplored. Here, we characterize the bacterial and fungal communities associated with brood cell compartments (cocoon, meconium, and prepupa) of the oil-collecting bee Centris aethyctera , and compare them with gut microbiota from adult Centris species. Using 16S rRNA and ITS amplicon sequencing, we show that microbiota are strongly compartmentalized, with distinct diversity patterns, taxonomic compositions, and inferred functional profiles across brood cell components. Contrary to our initial hypothesis, antibiotic-producing bacteria, particularly Actinomycetia, are most diverse and abundant in the meconium rather than the cocoon. Cocoons are enriched in hydrocarbon-degrading and nitrogen-cycling bacteria, while pre-pupae harbor distinct bacterial and fungal taxa, including genera with potential antimicrobial and symbiotic functions. Fungal communities are likewise structured, with taxa such as Aspergillus and Lecanicillium suggesting possible roles in pathogen defense. Core gut microbiota of adult Centris include acetic acid bacteria shared across species, with partial overlap with brood cell taxa, indicating potential transmission pathways. Together, our results reveal that Centris brood cells form a highly structured, antimicrobial-rich microenvironment likely shaped by maternal provisioning and environmental acquisition. These findings provide the first comprehensive description of microbiota across brood cell compartments in a solitary bee and identify ground-nesting bee systems as promising reservoirs for novel antimicrobial discovery.

Oxidative stress (OS) reflects a pathologic imbalance between excessive production of reactive oxygen species (ROS) and insufficient antioxidant defenses. Growing evidence indicates that a healthy gut microbiota (GM) is essential for regulating redox homeostasis, whereas gut dysbiosis contributes to elevated ROS levels and oxidative damage in DNA, lipids, and proteins. This redox disequilibrium initiates a cascade of cellular disturbances—including synaptic dysfunction, altered receptor activity, excitotoxicity, mitochondrial disruption, and chronic neuroinflammation—that can, in turn, impair cognitive and social functioning in metabolic and neuropsychiatric disorders via epigenetic mechanisms. In this review, we synthesize current knowledge on (1) how OS contributes to cognitive and social deficits through epigenetic dysregulation; (2) the role of disrupted one-carbon metabolism in epigenetically mediated neurological dysfunction; and (3) mechanistic links between leaky gut, OS, altered GM composition, and GM-derived epigenetic metabolites. We also highlight emerging microbiota-based therapeutic strategies capable of mitigating epigenetic abnormalities and improving cognitive and social outcomes. Understanding the OS–microbiota–epigenetic interplay may uncover new targetable pathways for therapies aimed at restoring brain and behavioral health.

Leafcutter ants are ecologically important insects that cultivate fungal gardens for sustenance, playing crucial roles in Neotropical ecosystems. Due to their ecological and evolutionary significance, high-quality genomic assemblies for the species in this fascinating group can provide a foundation for understanding their evolution. Here, we present a chromosome-scale, haplotype-resolved genome assembly for Acromyrmex octospinosus, a common leafcutter ant species broadly distributed in the Neotropics. Using PacBio HiFi sequencing (99x coverage) and Hi-C scaffolding (51x coverage), we generated both haplotype-resolved assemblies (312–314 Mb) and a haplotype-collapsed assembly (320 Mb), each containing 19 chromosomes. One hundred percent of the assembly is anchored to chromosome-level scaffolds, and the assemblies exhibit high contiguity (contig N50: 6.13–8.28 Mb), base accuracy (QV 61.5–61.8), and gene completeness (BUSCO scores: 98.3% to 98.4%). Synteny analysis between haplotypes revealed high concordance (96.0% to 96.8%) with minor structural variations, consistent with expectations for a diploid individual. Combining transcriptomic and homology-based protein evidence with ab initio predictions, we annotated 12,123 genes, achieving a near-complete BUSCO gene completeness of 99.6%. The high-quality assemblies significantly enhance the current genomic resources available for leafcutter ants, providing a foundation for future comparative genomic studies within Acromyrmex and across fungus-farming ants.

Cognitive impairment in various mental illnesses, particularly neuropsychiatric disorders, has adverse functional and clinical consequences. While genetic mutations and epigenetic dysregulations of several genes during embryonic and adult periods are linked to cognitive impairment in mental disorders, the composition and diversity of resident bacteria in the gastrointestinal tract—shaped by environmental factors—also influence the brain epigenome, affecting behavior and cognitive functions. Accordingly, many recent studies have provided evidence that human gut microbiota may offer a potential avenue for improving cognitive deficits. In this review, we provide an overview of the relationship between cognitive impairment, alterations in the gut microbiome, and epigenetic alterations during embryonic and adult periods. We examine how various factors beyond genetics—such as lifestyle, age, and maternal diet—impact the composition, diversity, and epigenetic functionality of the gut microbiome, consequently influencing cognitive performance. Additionally, we explore the potential of maternal gut microbiome signatures and epigenetic biomarkers for predicting cognitive impairment risk in older adults. This article also explores the potential roles of nutritional deficiencies in programming cognitive disorders during the perinatal period in offspring, as well as the promise of gut microbiome-targeted therapeutics with epigenetic effects to prevent or alleviate cognitive dysfunctions in infants, middle-aged adults, and older adults. Unsolved challenges of gut microbiome-targeted therapeutics in mitigating cognitive dysfunctions for translation into clinical practice are discussed, lastly.

Introduction: The combined genetic material of the microorganisms in the human body, known as the microbiome, is being increasingly recognized as a major determinant of human health and disease. Although located predominantly on mucosal surfaces, these microorganisms have profound effects on brain functioning through the gut–brain axis. Method: The content of the chapter is based on a study group session at the annual meeting of the American College of Neuropsychopharmacology (ACNP). The objective was to discuss the emerging relationship between the human microbiome and mental health as relevant to ACNP’s interests in developing and evaluating novel neuropsychiatric treatment strategies. The focus is on specific brain disorders, such as schizophrenia, substance use, and Alzheimer’s disease, as well as on broader clinical issues such as suicidality, loneliness and wisdom in old age, and longevity. Results: Studies of schizophrenia indicate that the microbiome of individuals with this disorder differs from that of non-psychiatric comparison groups in terms of diversity and composition. Differences are also found in microbial metabolic pathways. An early study in substance use disorders found that individuals with this disorder have lower levels of beta diversity in their oral microbiome than a comparison group. This measure, along with others, was used to distinguish individuals with substance use disorders from controls. In terms of suicidality, there is preliminary evidence that persons who have made a suicide attempt differ from psychiatric and non-psychiatric comparison groups in measures of beta diversity. Exploratory studies in Alzheimer’s disease indicate that gut microbes may contribute to disease pathogenesis by regulating innate immunity and neuroinflammation and thus influencing brain function. In another study looking at the microbiome in older adults, positive associations were found between wisdom and alpha diversity and negative associations with subjective loneliness. In other studies of older adults, here with a focus on longevity, individuals with healthy aging and unusually long lives had an abundance of specific microorganisms which distinguished them from other individuals. Discussion: Future studies would benefit from standardizing methods of sample collection, processing, and analysis. There is also a need for the standardized collection of relevant demographic and clinical data, including diet, medications, cigarette smoking, and other potentially confounding factors. While still in its infancy, research to date indicates a role for the microbiome in mental health disorders and conditions. Interventions are available which can modulate the microbiome and lead to clinical improvements. These include microbiome-altering medications as well as probiotic microorganisms capable of modulating the inflammation in the brain through the gut–brain axis. This research holds great promise in terms of developing new methods for the prevention and treatment of a range of human brain disorders. Keywords Aging Beta diversity Mental health Microbiome Microorganisms Probiotics

Both isolation by distance and isolation by environment occur in bacteria, and different diversification patterns may apply to different species. Streptomyces species, typified by producing useful natural products, are widespread in nature and possess high genetic diversity. However, the ecological processes and evolutionary mechanisms that shape their distribution are not well understood.

The evolution of mass raiding has allowed army ants to become dominant arthropod predators in the tropics. Although a century of research has led to many discoveries about behavioural, morphological and physiological adaptations in army ants, almost nothing is known about the molecular basis of army ant biology. Here we report the genome of the iconic New World army ant Eciton burchellii, and show that it is unusually compact, with a reduced gene complement relative to other ants. In contrast to this overall reduction, a particular gene subfamily (9‐exon ORs) expressed predominantly in female antennae is expanded. This subfamily has previously been linked to the recognition of hydrocarbons, key olfactory cues used in insect communication and prey discrimination. Confocal microscopy of the brain showed a corresponding expansion in a putative hydrocarbon response centre within the antennal lobe, while scanning electron microscopy of the antenna revealed a particularly high density of hydrocarbon‐sensitive sensory hairs. E. burchellii shares these features with its predatory and more cryptic relative, the clonal raider ant. By integrating genomic, transcriptomic and anatomical analyses in a comparative context, our work thus provides evidence that army ants and their relatives possess a suite of modifications in the chemosensory system that may be involved in behavioural coordination and prey selection during social predation. It also lays the groundwork for future studies of army ant biology at the molecular level.

Volume 11, no. 5, e02146-20, 2020, https://doi.org/10.1128/mBio.02146-20. We left out the appropriate permit information for collections done in Brazil. The following line should have been added to Acknowledgments (PDF page 16): “In Brazil, collections of biological samples and research on genetic resources were authorized by SISBIO permits 46555-1 to 46555-7 and CNPq permit 010936/2014-9.” This change does not affect the main text of the article in any way.

Many organisms partner with microbes to defend themselves against parasites and pathogens. Fungus-growing ants must protect Leucoagaricus spp., the fungal mutualist that provides sustenance for the ants, from a specialized fungal parasite, Escovopsis spp.