Biology subjects

Villalobos, J.

Publications and source records attributed to Villalobos, J..

4 recordsLinked to original sources

bioRxiv2026

Host genetics determines the fate of the Lactobacillaceae population in the small intestine

Whereas innate pattern recognition receptors bind evolutionary conserved moieties shared by diverse groups of microbes, control over closely related microorganisms is likely based on different principles and can be sensitive to genetic variation of the host. While the influence of host genetics on intestinal microbiome composition has been growing in appreciation, understanding of polymorphic mechanisms that regulate individual bacterial lineages requires complex approaches. Using gnotobiotic mouse monocolonized with Ligilactobacillus murinus (ASF361), we found that C57BL/6J (B6) mice harbored significantly more intestinal ASF361 (or other Lactobacillaceae genera) than did BALB/cJ (BALB/c) mice. The difference in ASF361 abundance was independent of adaptive immunity and bacteriotoxic factors. In B6 mice, ASF361 occupied ileal crypts, showed greater expression of adhesion-related molecules, and enriched expression of carbohydrate-metabolism pathways, whereas in BALB/c mice, ASF361 remained largely luminal and enriched expressed genes associated with starvation and stress. These findings highlight the importance of host genetic variation in shaping microbial colonization and suggest that such variation should be considered when evaluating probiotic strains and microbiota transplantation.

microbiology↗

bioRxiv2022

Novel cerebello-amygdala connections provide missing link between cerebellum and limbic system

The cerebellum is emerging as a powerful regulator of cognitive and affective processing and memory in both humans and animals and has been implicated in affective disorders. How the cerebellum supports affective function remains poorly understood. The short-latency (just a few ms) functional connections that were identified between the cerebellum and amygdala -a structure crucial for the processing of emotion and valence-more than 4 decades ago raise the exciting, yet untested, possibility that a cerebellum-amygdala pathway communicates information important for emotion. The major hurdle in rigorously testing this possibility is the lack of knowledge about the anatomy and functional connectivity of this pathway. Our initial anatomical tracing studies in mice excluded the existence of a direct monosynaptic pathway between cerebellum and amygdala. Using transneuronal tracing techniques, we have identified a novel disynaptic pathway that connects the cerebellar output nuclei to the basolateral amygdala. This pathway recruits the understudied intralaminar thalamus as a node. Using ex vivo optophysiology and super-resolution microscopy, we provide the first evidence for the functionality of the pathway, thus offering a missing mechanistic link between the cerebellum and amygdala. This discovery provides a connectivity blueprint between the cerebellum and a key structure of the limbic system. As such, it is the requisite first step toward obtaining new knowledge about cerebellar function in emotion, thus fundamentally advancing understanding of the neurobiology of emotion, which is perturbed in mental and autism spectrum disorders.

neuroscience↗

bioRxiv2020

A gut sensor for sugar preference

Summary Paragraph/AbstractAnimals innately prefer caloric sugars over non-caloric sweeteners. Such preference depends on the sugar entering the intestine.1-4 Although the brain is aware of the stimulus within seconds,5-8 how the gut discerns the caloric sugar to guide choice is unknown. Recently, we discovered an intestinal transducer, known as the neuropod cell.9,10 This cell synapses with the vagus to inform the brain about glucose in the gut in milliseconds.10 Here, we demonstrate that neuropod cells distinguish a caloric sugar from a non-caloric sweetener using the electrogenic sodium glucose co-transporter 1 (SGLT1) or sweet taste receptors. Activation of neuropod cells by non-caloric sucralose leads to ATP release, whereas the entry of caloric sucrose via SGLT1 stimulates glutamate release. To interrogate the contribution of the neuropod cell to sugar preference, we developed a method to record animal preferences in real time while using optogenetics to silence or excite neuropod cells. We discovered that silencing these cells, or blocking their glutamatergic signaling, renders the animals unable to recognize the caloric sugar. And, exciting neuropod cells leads the animal to consume the non-caloric sweetener as if it were caloric. By transducing the precise identity of the stimuli entering the gut, neuropod cells guide an animals internal preference toward the caloric sugar.

neuroscience↗

bioRxiv2019

Microplastic ingestion by a herring Opisthonema sp., in the Pacific coast of Costa Rica

Despite there is a growing interest in studying the presence and effects of microplastics (MP) in fishes and other aquatic species, knowledge is still limited in tropical areas. In this study, we examined the presence of MP in the gastrointestinal content of 30 filter feeders of thread herring, Opisthonema complex (Clupeiformes: Clupeidae) from the Central Pacific coast of Costa Rica. We detected the presence of MP in 100% of the individuals with an average of 36.7 pieces per fish, of which 79.5% were fibers and 20.5% particles. To our knowledge, this is the first study in Costa Rica that demonstrates the presence of MP in planktivorous fishes. The effects of microplastics ingestion by O. libertate and its transit through aquatic food webs should be studied in greater detail, with greater number of sampling points at different times of the year. However, our work confirms that contamination by microplastics is having direct effects on the marine life of Costa Rica.\n\nCapsuleThis is the first multidisciplinary study in Costa Rica demonstrating the presence and nature of microplastics in the digestive tract of planktivorous fish.

zoology↗