Biology subjects

Dua, M.

Publications and source records attributed to Dua, M..

5 recordsLinked to original sources

bioRxiv2025

Identification of bacterial signals that modulate enteric sensory neurons to influence behavior in C. elegans

The bacterial microbiome influences many aspects of animal health and disease. Some bacteria have beneficial functions, for example providing nutrients, whereas others act as pathogens. These bacteria are sensed by host cells to induce adaptive changes in physiology and behavior. While immune and intestinal cells detect bacterial signals through well-characterized mechanisms, recent studies indicate that neurons can also directly sense bacterial signals. However, the bacterial sensory mechanisms in neurons are less well understood. In the nematode Caenorhabditis elegans, the enteric sensory neuron NSM innervates the pharyngeal lumen and is directly activated by bacterial food ingestion; in turn, NSM releases serotonin to induce feeding-related behaviors. However, the molecular identities of the bacterial signals that activate NSM are unknown. To identify these signals, we systematically probed bacterial macromolecules from nutritive bacteria using biochemical approaches and GC-MS identification. We find that polysaccharides from gram-positive and gram-negative bacteria are sufficient to activate NSM. We further identify peptidoglycan from gram-positive bacteria as a specific component capable of activating NSM. NSM responses to polysaccharides require the acid-sensing ion channels DEL-3 and DEL-7, which localize to its sensory dendrite in the pharyngeal lumen. Ingestion of bacterial polysaccharides enhances feeding rates and reduces locomotion, matching the known effects of NSM on behavior. We also examine bacterial signals from pathogenic bacteria that can infect and kill C. elegans. This approach identifies prodigiosin, a metabolite from pathogenic Serratia marcescens, as a bacterial cue that prevents NSM activation by nutritive bacterial signals. This study identifies molecular signals that underlie neuronal recognition of nutritive bacteria in the alimentary canal and competing signals from a pathogenic bacterial strain that mask this form of recognition.

neuroscience↗

bioRxiv2024

The auditory midbrain mediates tactile vibration sensing

Vibrations are ubiquitous in nature, shaping behavior across the animal kingdom. For mammals, mechanical vibrations acting on the body are detected by mechanoreceptors of the skin and deep tissues and processed by the somatosensory system, while sound waves traveling through air are captured by the cochlea and encoded in the auditory system. Here, we report that mechanical vibrations detected by the bodys Pacinian corpuscle neurons, which are unique in their ability to entrain to high frequency (40-1000 Hz) environmental vibrations, are prominently encoded by neurons in the lateral cortex of the inferior colliculus (LCIC) of the midbrain. Remarkably, most LCIC neurons receive convergent Pacinian and auditory input and respond more strongly to coincident tactile-auditory stimulation than to either modality alone. Moreover, the LCIC is required for behavioral responses to high frequency mechanical vibrations. Thus, environmental vibrations captured by Pacinian corpuscles are encoded in the auditory midbrain to mediate behavior.

neuroscience↗

bioRxiv2022

Diverse states and stimuli tune olfactory receptor expression levels to modulate food-seeking behavior

Animals must weigh competing needs and states to generate adaptive behavioral responses to the environment. Sensorimotor circuits are thus tasked with integrating diverse external and internal cues relevant to these needs to generate context-appropriate behaviors. However, the mechanisms that underlie this integration are largely unknown. Here, we show that a wide range of states and stimuli converge upon a single C. elegans olfactory neuron to modulate food-seeking behavior. Using an unbiased ribotagging approach, we find that the expression of olfactory receptor genes in the AWA olfactory neuron is influenced by a wide array of states and stimuli, including feeding state, physiological stress, and recent sensory cues. We identify odorants that activate these state-dependent olfactory receptors and show that altered expression of these receptors influences food-seeking and foraging. Further, we dissect the molecular and neural circuit pathways through which these diverse cues are integrated by AWA. This reveals a modular organization in which state-related signals arising from different cell types in the body converge on AWA and independently control chemoreceptor expression. The synthesis of these signals by AWA allows animals to generate sensorimotor responses that reflect the animals overall state. Our findings suggest a general model in which state-dependent transcriptional changes at the sensory periphery modulate animals sensorimotor responses to meet their ongoing needs and states.

neuroscience↗

bioRxiv2021

The Sugar Porter gene family of Piriformospora indica: Nomenclature, Transcript Profiling and Characterization

Piriformospora indica is one of the prominent mutualistic root endophyte known to overcome phosphate and nitrogen limitation in a wide variety of plant species, reciprocally takes up carbohydrates for its survival and growth. A total of nineteen potential hexose transporters have been identified from P. indica genome, that may contributes to its potential of carbohydrate assimilation from host plant. Phylogenetic analysis assembles it in 10 groups within 3 clusters. To ease the study, systematic nomenclature were provided to 19 putative hexose transporters as "PiST1-PiST19" in accordance to their appearance on the supercontigs genome sequence of P. indica. The protein length ranges from 487 to 608 amino acids. Out of 19 putative hexose transporters, 9 have been predicted to contain 12 transmembrane domains (PiST1, PiST2, PiST5, PiST6, PiST9, PiST10, PiST11, PiST12 and PiST17), along with MFS family and Sugar porter subfamily motif. Therefore, transcripts were detected for these 9 genes. During colonization, three P. indica genes PiST1, PiST5 and PiST9 have shown induction as compared to axenic culture. Similarly during phosphate starvation, revealed PiST12 to be strongly enhanced. Carbon starvation study in liquid axenic culture resulted in induction of 4 genes, PiST6, PiST9, PiST12 and PiST17. We found co-relation in the expression pattern of PiPT and PiST12 during phosphate starvation. In silico analysis revealed the presence of functional conserved fucose permease (FucP) domain, involved in fructose transport. Phylogenetic analysis revealed that PiST12 groups closely with basidiomycetes hexose transporters. Further, functional complementation of {Delta}hxt null mutant revealed, PiST12 is able to complement growth on fructose and galactose but negligible on glucose.

plant biology↗

bioRxiv2020

Role of Sulphate Transporter (PiSulT) of Endophytic Fungus Serendipita indica in Plant Growth and Development

Sulfur is an important macronutrient required for the growth, development of plants and is a key component of many metabolic pathways. We have functionally characterized a high-affinity sulphate transporter (PiSulT) from an endophytic fungus Serendipita indica. The PiSulT belongs to the major facilitator superfamily (MFS) of membrane transporter. The PiSulT functionally complements the yeast sulphate transporter mutant HK14. PiSulT is a high-affinity sulphate transporter, having Km 15M. We found enhanced expression of PiSulT in external fungal hyphae which helps the fungus in the acquisition of sulphate from the soil. When knockdown (KD)-PiSulT-P.indica colonized with the plant, it results in an 8-fold reduction in the transfer of sulphate to the colonized plants as compared to the plants colonized with the WT S. indica, which suggests that PiSulT is playing a role in sulphate transfer from soil to host plant. Further, plants colonized with the WT S. indica were found to be healthy in comparison to the plants colonized with the KD-PiSulT-P.indica. Additionally, S. indica colonization provides a positive effect on total sulfur content and on plant metabolites like sulfate ions and glutathione, particularly under low sulphate condition. We observed that the expression of sulfur assimilation pathway genes of S. indica and plant is dependent on the availability of sulphate and on the colonization with the plant. Our study highlights the importance of PiSulT in the improvement of sulfur nutrition of host plant particularly under low sulphate condition and in plant growth development. This study will open new vistas to use S. indica as a bio-fertilizer in the sulphate deficient field to improve crop production. One-Sentence SummaryHigh-affinity sulphate transporter of Serendipita indica (PiSulT) transfer sulphate from soil to plant under low sulphate condition and improve plant growth and development.

microbiology↗