Evolutionarily conserved mechanisms of male germline development in flowering plants and animals

Sexual reproduction is the main reproductive strategy of the overwhelming majority of eukaryotes. This suggests that the last eukaryotic common ancestor was able to reproduce sexually. Sexual reproduction reflects the ability to perform meiosis, and ultimately generating gametes, which are cells that carry recombined half sets of the parental genome and are able to fertilize. These functions have been allocated to a highly specialized cell lineage: the germline. Given its significant evolutionary conservation, it is to be expected that the germline programme shares common molecular bases across extremely divergent eukaryotic species. In the present review, we aim to identify the unifying principles of male germline establishment and development by comparing two very disparate kingdoms: plants and animals. We argue that male meiosis defines two temporally regulated gene expression programmes: the first is required for meiotic commitment, and the second is required for the acquisition of fertilizing ability. Small RNA pathways are a further key communality, ultimately ensuring the epigenetic stability of the information conveyed by the male germline.

Growing up in a bubble: using germ-free animals to assess the influence of the gut microbiota on brain and behavior

There is a growing recognition of the importance of the commensal intestinal microbiota in the development and later function of the central nervous system. Research using germ-free mice (mice raised without any exposure to microorganisms) has provided some of the most persuasive evidence for a role of these bacteria in gut-brain signalling. Key findings show that the microbiota is necessary for normal stress responsivity, anxiety-like behaviors, sociability, and cognition. Furthermore, the microbiota maintains central nervous system homeostasis by regulating immune function and blood brain barrier integrity. Studies have also found that the gut microbiota influences neurotransmitter, synaptic, and neurotrophic signalling systems and neurogenesis. The principle advantage of the germ-free mouse model is in proof-of-principle studies and that a complete microbiota or defined consortiums of bacteria can be introduced at various developmental time points. However, a germ-free upbringing can induce permanent neurodevelopmental deficits that may deem the model unsuitable for specific scientific queries that do not involve early-life microbial deficiency. As such, alternatives and complementary strategies to the germ-free model are warranted and include antibiotic treatment to create microbiota-deficient animals at distinct time points across the lifespan. Increasing our understanding of the impact of the gut microbiota on brain and behavior has the potential to inform novel management strategies for stress-related gastrointestinal and neuropsychiatric disorders.

Exploring chalcolithic diet and mobility of humans and animals from Perdigões site

Chalcolithic diet at Perdigões (Reguengos de Monsaraz) was investigated using stable carbon and nitrogen isotope analysis of human bone collagen. Strontium isotopes of faunal dental enamel were used to establish the site local range and to distinguish the presence of non-local individuals. ATR-FTIR and EA analysis were used to determine the degree of bone diagenesis and to evaluate the reliability of the stable isotopic composition for paleodietary reconstruction. The individuals from which paleodietary results were obtained had a diet based on C3 terrestrial resources and some animal protein. Data from Perdigões site, was compared with the published data from other Iberian Chalcolithic populations. Site comparison revealed that diet through Iberian Peninsula have mainly maintained terrestrial dietary focus consistent with animal husbandry and farming on C3 plants with occasional intake of freshwater or marine resources. Strontium isotopic composition of enamel revealed that some of the individuals from Perdigões site were non-local; Resumo: A dieta de indivíduos do período Calcolítico dos Perdigões (Reguengos de Monsaraz) foi investigada através de análise de isótopos estáveis de carbono e azoto no colagénio ósseo. Isótopos de estrôncio do esmalte dentário de fauna foram utilizados para estabelecer o sinal local dos Perdigões, permitindo distinguir a presença de alguns indivíduos e fauna não-locais. A avaliação da diagénese óssea foi efectuada através de análises realizadas com analisador elementar e com ATR-FTIR, de forma a validar dos resultados isotópicos obtidos. Os indivíduos para os quais foi possivel obter resultados isotópicos de carbono e azoto apresentam uma dieta baseada em recursos terrestres, plantas C3, e alguma proteína animal. A comparação efectuada com outros sitios arqueológicos da Peninsula Ibérica revelaram que a dieta das populações é sobretudo feita à base de plantas C3, com ingestão de alguma proteina animal e ingestão ocasional de produtos marinhos ou provenientes de água doce.