Biology subjects

Ribeiro, L. R.

Publications and source records attributed to Ribeiro, L. R..

2 recordsLinked to original sources

bioRxiv2021

Wild birds as reservoirs of multidrug-resistant enterobacteria in Mulungu, Brazil

Caatinga is a biome unique to Brazil that is degraded by anthropogenic actions, which lead to the loss of biodiversity putting many species at risk of extinction. The Ceara State is located in the Caatinga and has a rich avifauna comprised of 433 species including 13 species that are threatened with extinction, which are found in the Baturite Massif. The aim of this study was to investigate the frequency and diversity of enterobacteria in wild birds and to determine their susceptibility to antimicrobials. Cloacal swab samples were collected from 50 individuals of 28 different species, including the Ceara Gnatheter (Conopophaga cearae) and Red-necked Tanager (Tangara cyanocephala cearensis), which are classified as vulnerable (VU) by the Brazilian Ministry of the Environment. A total of 55 isolates belonging to 14 different species of Enterobacteriaceae were identified. Among these, Pantoea agglomerans and Escherichia coli were the most prevalent species with isolation rates of 36% and 26%, respectively. The highest rate of antimicrobial resistance found was to ampicillin (41.8%), followed by nalidixic Acid (36.3%) and amoxicillin associated with clavulanic acid (32.7%). The drugs with the best efficacy were tobramycin (96.4%), ciprofloxacin (92.6%) and tetracycline (90.9%). Multidrug resistance was observed in 23.5% of the analyzed strains. This research provides important information about the composition of the cloacal microbiota of wild birds in Mulungu, Brazil, as well as their health status. In addition, these results demonstrate that they harbor multidrug-resistant strains of Enterobacteriaceae.

microbiology↗

bioRxiv2020

Constitutive ghrelin receptor activity modulates AMPA receptor traffic and supports memory formation

The ability of animals to store and retrieve food caches in the wild requires the integration of biological signals of hunger, satiety and memory. The role of ghrelin in regulating feeding and memory makes ghrelin receptors an important target to shape the required cellular and molecular responses. We investigated the effects of the high ligand-independent activity of the ghrelin receptor on the physiology of excitatory synapses. Blocking this type of activity produced a decrease in the synaptic content of AMPA receptors in hippocampal neurons and a reduction in GluA1 phosphorylation at Ser845. Impaired constitutive activity from the ghrelin receptor increased surface diffusion of AMPA receptors and impaired AMPA receptor synaptic delivery mediated by chemical long-term potentiation. These observations support a role for the constitutive activity of the ghrelin receptor in regulating AMPA receptor trafficking under basal conditions and synaptic plasticity. Accordingly, we found that blocking the ghrelin receptor constitutive activity impairs spatial and recognition memory. Impact statementThis work uncovers a role for the constitutive activity of the ghrelin receptor in memory, and in the regulation of the synaptic levels of AMPA receptors, their mobility and synaptic plasticity. Underscoring the importance of deciphering the physiological role of constitutive ghrelin receptor activity, ghrelin receptor inverse agonism is now being considered as a therapy to treat alcohol use disorder.

neuroscience↗