Unravelling large-scale patterns and drivers of biodiversity in dry rivers.

More than half of the world's rivers dry up periodically, but our understanding of the biological communities in dry riverbeds remains limited. Specifically, the roles of dispersal, environmental filtering and biotic interactions in driving biodiversity in dry rivers are poorly understood. Here, we conduct a large-scale coordinated survey of patterns and drivers of biodiversity in dry riverbeds. We focus on eight major taxa, including microorganisms, invertebrates and plants: Algae, Archaea, Bacteria, Fungi, Protozoa, Arthropods, Nematodes and Streptophyta. We use environmental DNA metabarcoding to assess biodiversity in dry sediments collected over a 1-year period from 84 non-perennial rivers across 19 countries on four continents. Both direct factors, such as nutrient and carbon availability, and indirect factors such as climate influence the local biodiversity of most taxa. Limited resource availability and prolonged dry phases favor oligotrophic microbial taxa. Co-variation among taxa, particularly Bacteria, Fungi, Algae and Protozoa, explain more spatial variation in community composition than dispersal or environmental gradients. This finding suggests that biotic interactions or unmeasured ecological and evolutionary factors may strongly influence communities during dry phases, altering biodiversity responses to global changes.

antiCD49d Ab treatment ameliorates age-associated inflammatory response and mitigates CD8+ T-cell cytotoxicity after traumatic brain injury.

Patients aged 65 years and older account for an increasing proportion of patients with traumatic brain injury (TBI). Older TBI patients experience increased morbidity and mortality compared to their younger counterparts. Our prior data demonstrated that by blocking α4 integrin, anti-CD49d antibody (aCD49d Ab) abrogates CD8+ T-cell infiltration into the injured brain, improves survival, and attenuates neurocognitive deficits. Here, we aimed to uncover how aCD49d Ab treatment alters local cellular responses in the aged mouse brain. Consequently, mice incur age-associated toxic cytokine and chemokine responses long-term post-TBI. aCD49d Ab attenuates this response along with a T helper (Th)1/Th17 immunological shift and remediation of overall CD8+ T cell cytotoxicity. Furthermore, aCD49d Ab reduces CD8+ T cells exhibiting higher effector status, leading to reduced clonal expansion in aged, but not young, mouse brains with chronic TBI. Together, aCD49d Ab is a promising therapeutic strategy for treating TBI in the older people. Graphic abstract: Aged brains after TBI comprise two pools of CD8 + T cells . The aged brain has long been resided by a population of CD8 + T cells that's exhaustive and dysfunctional. Post TBI, due to BBB impairment, functional CD8 + T cells primarily migrate into the brain parenchyma. Aged, injury-associated microglia with upregulated MHC class I molecules can present neoantigens such as neuronal and/or myelin debris in the injured brains to functional CD8+ T, resulting in downstream CD8+ T cell cytotoxicity. aCD49d Ab treatment exerts its function by blocking the migration of functional effector CD8 + T cell population, leading to less cytotoxicity and resulting in improved TBI outcomes in aged mice.

Plantas medicinales: Efecto antibacteriano in vitro de Plantago major L, Erythroxylum novogranatense, Plowman var truxillense y Camellia sinensis sobre bacterias de importancia estomatológica / Medicinal plants: Antibacterial effect in vitro de Plantago major L, Erythroxylum novogranatense, Plowman var truxillense and Camellia sinensis on stomatologic importance bacteria

El objetivo de la investigación fue comparar la actividad antibacteriana in vitro de los extractos hidroalcohólicos de tres plantas medicinales: Plantago major L. (llantén), Erythroxylum novograntense var truxillense (coca trujillo) y Camellia sinensis (té verde) mediante el método de difusión en agar con discos, sobre cinco cepas patrones de bacterias orales: Streptococcus mutans ATCC 25175, Lactobacillus acidophilus. ATCC 314, Actinomyces viscosus ATCC 15987, Prevotella melaninogenicus ATCC 25845 y Fusobacterium nucleatum ATCC 25586. Se obtuvieron extractos hidroalcohólicos de principios activos totales procedentes de las hojas secas de cada una de las plantas, mediante maceración alcohólica con alcohol etílico al 70 % y posterior evaporación del solvente con el empleo del rotavapor. Cada extracto se diluyó en alcohol etílico al 70 % en las concentraciones de 25 µg/mL y 50 µg/mL. Estas soluciones fueron comparadas con PerioAid® (clorhexidina 0,012 %) como control positivo y con alcohol etílico al 70 %, como control negativo. Al realizar las pruebas de sensibilidad in vitro, se obtuvieron los siguientes resultados: los tres extractos hidroalcohólicos en ambas concentraciones presentaron actividad antibacteriana mayor al alcohol etílico (5,8 mm) y menor que el PerioAid® (22,0 mm) sobre las cinco cepas bacterianas en estudio. La mayor actividad presentó el extracto hidroalcohólico de Camellia sinensis a 50 µg/mL, la menor actividad presento Plantago major a 25 µg/mL. Se concluye que los tres extractos hidroalcohólicos en las diluciones de 25 y 50 µg/mL presentaron actividad antibacteriana sobre Streptococcus mutans, Lactobacillus acidophilus, Actinomyces viscosus, Prevotella melaninogenica y Fusobacterium nucleatum. El efecto antibacteriano aumentó con la concentración en P. melaninogenica, que fue la cepa más sensible y A. viscosus la menos sensible.