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Results for “chemosensation”

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PubMed1979

Studies on bacterial chemotaxis. IV. Interaction of maltose receptor with a membrane-bound chemosensing component.

Highly purified maltose receptor of Escherichia coli was bound to Sepharose 4B via a long spacer and affinity chromatography was performed to isolate the membrane-bound proteins having affinity for the maltose receptor. The experiments were carried out either in the presence of maltose or in the absence of maltose and the proteins absorbed on the mattix were identified by two-dimensional gel electrophoresis. The results showed that the maltose receptor interacted with the product of tar gene, one of the methyl-accepting chemotaxis proteins, only in the presence of maltose.

Cell Membrane↗

PubMed2026

Genome-wide identification of olfactory receptor and odorant-binding protein gene families and their roles in Heliothine chemosensory evolution.

Chemosensory systems play key roles in the survival and reproductive success of insects. Two large and diverse chemosensory gene families, odorant receptors (ORs) and odorant-binding proteins (OBPs), play critical roles in insect chemosensation and mediate odour-guided behaviours. In the process of insect chemosensation, odorants from the environment pass through pores in the antennal sensilla and become soluble in the sensillar lymph, either directly on contact or by binding to an OBP. Solubilized odour molecules diffuse through the lymph until they reach and activate their cognate ORs, sending electrophysiological signals to the insect brain. To better understand the evolutionary roles of OR and OBP gene families among members of the Heliothinae, we systematically characterized these two gene families in Chloridea virescens (Lepidoptera: Noctuidae). A total of 81 ORs and 49 OBPs were identified genome-wide. Based on the number and positions of conserved cysteine residues, the OBPs were classified into three types: 34 Classic OBPs, 8 Minus-C OBPs and 7 Plus-C OBPs. Phylogenetic analyses identified potential gene duplications and losses within OR and OBP gene families among members of the Heliothinae, which may be associated with differences in their volatile sensation and olfactory behaviours. Further motif and structural analyses identified a conserved region that was unique among pheromone receptors and predicted as key residues of the binding pocket, implying its critical role in pheromone detection. Future work should focus on experimentally validating its function. Overall, our findings provide important insights into how chemosensory gene evolution contributes to ecological adaptation and reproductive isolation in the Heliothine moths.

Animals↗

PubMed2026

Transcriptomic responses of Porphyrophora sophorae larvae during licorice root colonization reveal coordinated remodeling of translation, mitochondrial energy metabolism and defense-related genes.

BACKGROUND: Porphyrophora sophorae is a subterranean piercing-sucking scale insect that damages licorice (Glycyrrhiza uralensis) roots, but the molecular responses associated with larval root colonization remain insufficiently defined. METHODS: We compared non-parasitic larvae (NP) and root-colonizing larvae (RC) using six RNA-seq libraries, de novo transcriptome assembly, DESeq2-based differential expression analysis, GO/KEGG enrichment, annotation-based candidate gene screening, and RT-qPCR validation of selected genes. RESULTS: Sequencing yielded 260.91 million clean reads, and de novo assembly produced 60,794 non-redundant transcripts. DESeq2 identified 703 FDR-significant DEGs, including 49 upregulated and 654 downregulated genes in RC larvae. Upregulated genes were mainly associated with translation- and ribosome-related processes, whereas downregulated genes were enriched in mitochondrial, oxidation-reduction, energy metabolism, and oxidative phosphorylation-related functions. Annotation-based screening identified 75 FDR-significant candidate genes associated with chemosensation, defense-related responses, and energy metabolism, with mitochondrial energy metabolism-related genes forming the largest module. RT-qPCR validation based on the raw Ct data showed concordant expression directions for ten selected transcript targets. CONCLUSIONS: Root colonization in P. sophorae larvae was associated with coordinated transcriptional remodeling involving selective activation of translation-related processes, adjustment of mitochondrial energy metabolism, and changes in defense-related gene expression. These results provide candidate molecular targets for future functional studies of host contact, feeding establishment, and physiological adjustment in this subterranean scale insect.

Animals↗

PubMed2025

Systematic identification and characterization of regulators of aryl hydrocarbon receptor signaling.

The human aryl hydrocarbon receptor (AHR) integrates chemical signals derived from the environment, gut microbes, and endogenous sources to regulate processes ranging from intestinal barrier integrity to xenobiotic detoxification. Despite strong evidence that dysregulation of AHR signaling is a causal factor in metabolic and autoimmune disorders, we currently lack a comprehensive understanding of the factors that regulate AHR activity in human cells. Here, we use genome-scale CRISPR screening to systematically identify regulators of AHR signaling in hepatocytes. The resulting datasets recapitulate the core AHR signaling pathway and identify a large network of regulators. Many of these factors have roles beyond AHR signaling, reflecting that AHR signaling is deeply integrated into human cell biology. We further dissect this network to reveal novel modes of regulation of AHR expression, protein levels, and signaling. For example, we find that the E3 ubiquitin ligase UBR5 sustains AHR signaling by counteracting degradation of ligand-bound AHR. Finally, we identify components of the AHR regulatory network that are specific to cell types and ligands as potential nodes to manipulate AHR signaling in a targeted manner for therapeutic benefit. Overall, our results define the regulatory network that underpins AHR activation, with implications for our understanding of host-microbe interactions and integrative chemosensation and the etiology of metabolic and inflammatory disorders.

Journal Article↗

PubMed2026

Locus coeruleus activation transforms cortical taste representations.

Noradrenergic neurons in the locus coeruleus (LC) shape sensory processing, yet how LC activity influences population taste coding remains unclear. Using optogenetic LC activation with miniscope imaging in the gustatory cortex (GC), we examined LC modulation of multiple taste attributes. Phasic LC activation strengthens correlations between neuronal responses and palatability and expands the dynamic range of stimulus representations along a palatability axis. This expansion is driven by an aversive shift in the representations of all tastants except sucrose, the most palatable stimulus. For mixture ratio and concentration, phasic activation expands and rotates attribute axes, potentially reflecting dependencies between these attributes and palatability. These transformations likely arise from multiplicative gain modulation and more flexible tuning changes. Tonic LC activation affects fewer neurons and does not expand attribute axes. Together, the findings show that LC activation reorganizes GC population geometry in a pattern-dependent manner, linking neuromodulation with feeding behavior and affective processing.

CP: neuroscience↗

PubMed2025

Transcriptional interference gates monogenic odorant receptor expression in ants.

Communication is crucial to social life, and in ants, it is mediated primarily through olfaction. Ants have more odorant receptor (OR) genes than any other group of insects, generated through tandem duplications that produce large genomic arrays of related genes. The mechanism by which olfactory sensory neurons (OSNs) produce a single functional OR from these arrays remains unclear. In ant OSNs, only mRNA from one OR in an array is exported into the cytoplasm, while upstream genes are silent and transcripts from downstream genes remain nuclear. Here, we show that readthrough transcription in the downstream direction generates non-translated transcripts. We also find that OR promoters are bidirectional, producing antisense long non-coding RNAs. We suspect that neither readthrough nor antisense transcription produces functional RNA but that bidirectional transcription alone is critical to suppressing the expression of all other OR genes in a tandem array. Finally, we present evidence that this regulatory architecture is conserved across ants and bees, suggesting that this mechanism for functionally monogenic OR expression is widespread in insects with expanded OR repertoires.

Animals↗

PubMed2026

Sex pheromone communication and its regulation by the sex determination pathway in cockroaches.

Sexual communication in animals orchestrates a series of interactive behaviors from locating and recognizing potential partners to courtship and final mating decisions and is thus critical for sexual reproduction and population fitness. Highly efficient communication between the sexes requires not only the production and emission of species-specific signals but also their precise detection and interpretation by the receiving individuals. Cockroaches, as one of the most evolutionarily ancient and successful group of insects, are quintessential chemical communicators that rely heavily on sex pheromones for sexual communication. They have long served as excellent model organisms in studies of chemical ecology. Although the biochemical characterization of sex pheromones in several species was largely accomplished during the last century, the past two decades have witnessed remarkable progress in understanding the molecular genetics of sex pheromone communication and its regulation, particularly driven by functional genomics. This review first provides an updated comparative survey of the pheromone components identified across distinct taxa. We then synthesize, but not limited to, recent advances in identification of key molecules controlling sex pheromone production, characterization of candidate chemosensory receptors and their neural processing pathways, and the regulatory roles of the sex determination cascade in shaping sexually dimorphic traits in both pheromone production and perception. Finally, we highlight key scientific questions that remain unsolved and propose future directions aimed at extending our mechanistic understanding of cockroach pheromone communication, as well as at developing behavior-based pest management strategies.

biosynthetic pathway↗