Search Results (421)

Olfactory (or odorant) receptors (ORs) were initially characterized in 1991 by Drs. Richard Axel and Linda Buck, and subsequent additional efforts have contributed to our understanding of their canonical function in odorant identification in the nasal cavity, including ligands for many of the ORs and the signaling pathways involved. More recently, OR transcripts and proteins have been identified in cells and organs outside of the nasal cavity, ranging from skin to sperm to tumors, suggesting that they have biological roles in ectopic locations other than their canonical function of odorant molecule detection in the nose. This mini narrative review discusses ectopic human ORs and their potential ligand-activated functions in the skin, lung, and sperm, as well as in diseases such as nonalcoholic steatohepatitis (NASH), melanoma and prostate cancer. Full article

Recent advances in machine learning are transforming biological research by offering powerful tools to address complex challenges across the life sciences. In particular, deep learning approaches now enable accurate predictions of protein structure and function, opening new avenues for investigating proteomic diversity in non-model organisms. In this study, we conducted a genomic case study that examines the predicted structure and diversity of odorant receptor (OR) proteins in two species of longhorn beetles (Cerambycidae) with divergent life histories: the highly specialized red milkweed beetle (Tetraopes tetrophthalmus) and the broadly polyphagous Asian longhorned beetle (Anoplophora glabripennis). Using leading predictive algorithms, we inferred the structure of beetle-encoded OR genes, compared confidence scores, and assessed protein diversity across OR families and between the two genomes. Unsupervised clustering applied to pairwise protein comparisons revealed an expected strong correlation between structure and sequence, while supporting the evolutionary classification of previously predicted OR groups and revealing new evidence of previously unrecognized OR subclusters. Notably, we identify specific proteins exhibiting substantial structural divergence despite relatively low sequence divergence with other paralogs, suggesting potential outliers subject to unusual evolutionary processes. These results highlight the utility of statistical learning for uncovering patterns of protein evolution and structural diversity in understudied insect genomes. Full article

The perception of the odor of fatty acids provides individuals with information about the nutritional content of foods. This perception varies depending on biological and genetic factors. Previous studies have shown that odorant binding proteins (OBPs) present in olfactory mucus play an important role in capturing and transporting odorants, typically lipophilic molecules, through the mucus to the olfactory receptors (ORs). The main objective of this research was to study the role of the rs2590498 (A/G) polymorphism of the human OBPIIa gene on the threshold and intensity of odor perception of palmitic (PA), oleic (OA) and linoleic (LA) acids. Volunteers were genotyped for OBP polymorphisms and classified as normosmic or hyposmic based on their threshold for n-butanol. The results show that normosmic or AA genotype participants perceived the odors of PA, OA, and LA at lower concentrations and with greater intensity than hyposmic or AG/GG genotype participants. Furthermore, the perception intensity reported by participants showed the following decreasing order: LA > OA > PA. These findings indicate that the intensity and threshold of perception depend on the lipophilicity of the molecule. These results indicate that genetic and biological factors, as well as the chemical properties of the molecules, play a key role in the olfactory perception of fatty acids. Full article

Most plant-based essential oil repellent products currently available on the market utilize a “green” approach based on the volatile properties of essential oils. In general, these essential oils contain terpenes, terpenoids, phenylpropanoids or benzenoids that can be used to either (1) eliminate a human’s scent through a process called odor masking, or (2) interfere with an insect’s ability to detect a person’s scent through interaction with both olfactory receptors and odorant binding proteins. Additionally, many of the essential oil blends that have been developed have been shown to exhibit antimicrobial and therapeutic properties. The primary drawback to using essential oil-based repellents is that their protection times vary widely, and typically last only a short period of time due to the volatile nature of the active ingredients, as well as differences in concentration and formulation among products. Encapsulation, nano-delivery systems, and rationally designed blend combinations are being proposed as potential methods to delay the release of the essential oil active ingredients, thus extending the duration of effectiveness of the repellent product. Since essential oils represent complex mixtures, there is a possibility that resistance to the repellent active ingredients could develop differently than it would for single-active agents. However, before such resistance can be assessed, the repellents must undergo extensive safety evaluations, along with standardized efficacy assessments against Environmental Protection Agency (EPA)-approved repellent products, and ultimately, field trials must be conducted in areas where the repellents will be used to prevent vector-borne diseases. In addition to conducting these evaluations, the repellents must comply with existing state and federal pesticide regulations. Full article

Background/Objectives: The Chinese porcupine (Hystrix hodgsoni) is a distinctive rodent species characterized by specialized ecological adaptations and sensory traits; however, genomic resources for this species have remained limited. This study aims to provide a reliable reference for comparative and evolutionary analyses by constructing a high-quality genome. Methods: We generated a chromosome-level genome assembly of the Chinese porcupine using long-read sequencing combined with chromatin conformation-based scaffolding, followed by comprehensive structural and functional annotation. Comparative genomic analyses across representative mammals and functional enrichment analyses were conducted to investigate lineage-specific gene family dynamics. Results: The assembled genome shows high contiguity and completeness. Comparative analyses revealed a substantial number of gene families significantly expanded along the porcupine lineage. Functional enrichment demonstrated strong overrepresentation of olfactory-related processes, including olfactory receptor activity, odorant binding, and detection of chemical stimuli. Additionally, several expanded families were associated with epidermal differentiation, keratinization, and skin development. Conclusions: Gene family expansions in the Chinese porcupine are biased toward sensory perception and epidermal functions, suggesting potential genetic bases for its enhanced environmental sensing and integumentary specialization. This assembly provides an important genomic resource for porcupine research and new insights into the molecular mechanisms underlying sensory and skin-related adaptations in rodents. Full article

Incretin receptor agonists (IRAs) such as GLP-1-based therapies improve metabolic and cognitive outcomes and enhance brain insulin signaling. One way that IRAs could have these actions is by affecting the blood–brain barrier (BBB); however, IRA-BBB interactions are poorly studied. Here, we examined the ability of insulin and IRAs to affect each other’s transport across the BBB in lean mice. We found that intracerebroventricular (ICV) administration of the insulin receptor antagonist S961 did not affect the blood-to-brain transport of the bioactive fragment of the IRA, ¹²⁵I-dulaglutide (BAF). In contrast, ¹²⁵I-dulaglutide (BAF) co-administered with intravenous (IV) insulin significantly enhanced ¹²⁵I-dulaglutide (BAF) BBB transport into whole brain, olfactory bulb, parietal cortex, and pons, demonstrating insulin-dependent modulation of IRA BBB transport. Regional transport rates for ¹²⁵I-dulaglutide (BAF) across the brain varied by ~2.5-fold, with the fastest transport into the olfactory bulb, frontal cortex, cerebellum, and pons. Co-administration of IV dulaglutide (BAF) did not alter ¹²⁵I-insulin BBB transport rates (K_i) but did reduce reversible insulin binding (V_i) at the BBB by >50%, suggesting rapid effects on BBB insulin receptors. To explore the effects of chronic IRA administration, lean mice were treated with semaglutide for two weeks. Body weight and food intake were unchanged, but female mice showed reduced fasting levels of serum insulin and GLP-1 and decreased insulin transport into whole brain, while male mice showed a reduction in insulin binding at the BBB. Chronic semaglutide also reduced ¹²⁵I-insulin BBB transport in female mice when studied with in situ perfusion, a procedure that removes the immediate influence of serum factors. Together, these findings demonstrate reciprocal and female-selective interactions between IRAs and insulin at the BBB. Acute insulin enhances the BBB transport of an IRA in female mice, whereas chronic IRA exposure selectively impairs insulin BBB transport in females, highlighting the BBB as a dynamic and hormone-sensitive interface with implications for long-term treatment in mouse models and potential for translation impact in humans. Full article

This study systematically investigated the application effects of exogenous enzymes (tannase/papain) during black tea fermentation, aiming to optimize flavor. Tannase treatment significantly reduced astringent substances like tea polyphenols and enhanced 11 metabolites, including Myricetin-3-O-arabinoside, thereby effectively enhancing fruity and sweet aromas. Papain treatment increased free amino acids and accumulated Myricetin-3-O-arabinoside and Vitexin-7-O-glucoside, significantly enhancing umami and floral flavors. Both enzyme treatments increased the odor activity value (OAV) of key aroma compounds such as (Z)-3-Hexen-1-ol and 1-Hexanol. Molecular docking revealed that hydrophobic interactions and hydrogen bonding are the key driving forces for aroma compound binding, OR5M3 and OR1A1 are key olfactory receptors for black tea aroma perception, and Benzene, n-butyl- was identified as a key aroma compound for the studied receptors. Overall, exogenous enzyme technology significantly changed the flavor of traditional black tea by reducing bitterness and astringency, as well as enhancing sweetness and floral aroma. Full article

The aroma of lemon is an important indicator of its quality, but there is still a lack of comparative research on the flavor components of different varieties of lemon and the interaction between olfactory receptors. This study conducted a combined analysis of volatile components in the peel and flesh of six varieties of lemons using GC-MS and GC-IMS. The random forest algorithm in machine learning was used to screen differential metabolites and perform molecular docking with all 389 olfactory receptors to analyze their potential interaction relationships. Hydrophobic interactions and hydrogen bonds are the most common interactions between odor molecules and olfactory receptors, and amino acids such as PHE, TYR, ASN, and HIS have the highest frequency of interaction. These findings offer crucial insights into the molecular mechanisms underlying lemon flavor. They also furnish a theoretical foundation for enhancing and utilizing lemon flavor quality. Full article

Indigenous sheep breeds represent valuable reservoirs of genetic diversity shaped by long-term adaptation to local environments and management systems. Greek autochthonous sheep breeds remain underrepresented in genomic and functional studies. The objective of this study was to characterize and compare coding sequence variation in three indigenous Greek sheep breeds—Lesvos (LES), Serres (SER), and Thrace (THR)—and to identify shared and breed-associated functional patterns. The study was designed using a two-stage approach, comprising a discovery (exploratory) phase and a validation phase. In the discovery phase, whole genome sequencing data (one animal per breed; total n = 3; mean sequencing depth ~36.9×) were analyzed to identify protein-altering exonic variants, focusing on missense single-nucleotide polymorphisms (SNPs) and exonic insertions/deletions (indels). Variants were examined at breed-specific and comparative levels, followed by functional enrichment analyses using Gene Ontology (GO) and KEGG pathways. Normalized variant density metrics identified genes with elevated polymorphism levels. In the validation phase, a subset of prioritized missense SNPs was genotyped in an independent cohort of 54 animals (18 per breed) using MassARRAY genotyping. Genes harboring prioritized missense SNPs showed a conserved enrichment profile across breeds, dominated by genome maintenance, DNA repair, cytoskeletal organization, and core regulatory functions. Distinct breed-associated patterns were also observed. LES showed enrichment in metabolic, biosynthetic, and sensory-related processes, SER in regulatory and signaling functions, and THR in cytoskeletal, extracellular matrix, and organelle-associated pathways. Polymorphism density analyses highlighted highly variable genes across breeds, including olfactory receptor (OR) gene families, keratin-associated protein genes (KRTAPs), and loci involved in immune and regulatory functions (e.g., PRKDC, CDH15). The validation phase confirmed the expected allele frequency patterns for most prioritized SNPs, supporting the robustness of the approach. This study identifies functionally relevant coding variation across Greek indigenous sheep breeds, revealing conserved genomic patterns and breed-associated signatures linked to metabolic, structural, and regulatory processes. Full article

The skin–brain axis constitutes a complex, bidirectional network integrating cutaneous sensory, immune, and neuroendocrine systems with central neural circuits involved in emotion regulation, stress responsivity, and social cognition. Advances in psychodermatology and cosmetic science have progressively extended this framework to the emerging field of neurocosmetics, which explores how topical formulations, sensorial properties, and cutaneous neuromodulators may influence psychological well-being, affective states, and perceived stress. The aim of this narrative review is to synthesize current evidence on the biological foundations of the skin–brain axis and to critically examine the implications of these mechanisms for neurocosmetic interventions from a psychological and psychiatric perspective. It describes the biological substrates underlying skin–brain communication, including the cutaneous hypothalamic–pituitary–adrenal axis, neuropeptides, neurotrophins, transient receptor potential channels, and endocannabinoid signaling, and examines how these pathways are targeted by neurocosmetic interventions. Particular attention is devoted to neuroactive compounds, such as peptides, cannabinoids, botanicals, and aromatherapeutic molecules, as well as to sensorial strategies involving texture, temperature, and olfactory cues, which may modulate mood, anxiety, and self-perception through peripheral mechanisms. From a psychological and psychiatric perspective, the review discusses the intersection between stress-related skin conditions, body image disturbances, and emotional dysregulation, highlighting how cosmetic practices may influence subjective well-being beyond purely aesthetic outcomes. Methodological limitations of the existing literature, including the heterogeneity of study designs and outcome measures, as well as ethical considerations related to mood- and stress-related claims in cosmetic products, are critically examined. Finally, future research directions are outlined, and a translational framework is proposed to integrate dermatology, neuroscience, and mental health within next-generation cosmetic science. Full article

This study explored the flavor profiling of baked potatoes, with a focus on how maturity affects the volatile flavor. By using HS-SPME-GC-MS, sensory evaluation, multivariate statistical analysis and computational modeling, a total of 99 volatile compounds were finally identified. Multivariate statistical analysis yielded 36 different important compounds (VIP > 1, p < 0.05). Subsequently, combined with relative odor activity value (ROAV), four key compounds including 2-ethyl-3,5-dimethylpyrazine, 2,6-diethylpyrazine, ethyl acetate and benzeneacetaldehyde were identified as potential indicators of baked potatoes with different maturities. Further, molecular docking analysis revealed the interactions between key pyrazine compounds and human olfactory receptors OR5K1 through hydrogen bonds and other interactions. These findings provide new insights into the relationship between potato maturity and flavor differences, and also lays a foundation for in-depth exploration into flavor identification and perception. Full article

The tomato leaf miner, Phthorimaea (Tuta) absoluta, Meyrick 1917 is recognized as a highly destructive pest, causing significant economic losses to crops in both greenhouse and open field environments across four continents: Asia, Africa, Europe, and South America. High genetic homogeneity among populations from various regions and countries indicates significant gene flow between P. absoluta populations, suggesting a lack of geographical barriers to dispersion. Furthermore, P. absoluta has developed resistance to insecticides due to target-site mutations or metabolic resistance, which enable the insect to withstand lethal doses of insecticides. To control this insect pest, the plant-mediated RNA interference (RNAi) is most promising host-induced gene silencing technique, utilized the plant’s machinery to express double-stranded (dsRNA), which triggers the RNAi pathway in P. absoluta. Due to thermal tolerance, the P. absoluta has increased its area of invasion by 600 km per year over 9 years. Female P. absoluta releases pheromones that are recognized by males with a sophisticated olfactory circuit on their antenna. Pheromone binding proteins (PBPs) play a crucial role in mate recognition and attraction, and their expression peaks during courtship, specifically around 6:00 a.m. Given its potential to significantly alter the insect genome, clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) offer a revolutionary strategy to control P. absoluta. Furthermore, this pest has developed remarkable adaptations to survive on unfavorable hosts by secreting specific proteins from its salivary glands that detoxify plant defenses. Insecticide resistance is likely the cause of field control failures of P. absoluta. Biological control, sex pheromone traps, and cultural control are the most promising approaches to address insecticide resistance resulting from these failures. Therefore, the implementation of integrated control programs and appropriate resistance management strategies is necessary to keep P. absoluta infestations under economic damage thresholds. Full article

The olfactory system plays a crucial role in mediating fish behaviour, including reproduction. Senegalese sole (Solea senegalensis) is an important aquaculture flatfish species in Europe, in which reproductive dysfunction in captive males has been linked to potential alterations in chemical communication. Despite the expanded repertoire of olfactory receptor genes described for this species, detailed information on the cellular organization of its olfactory organs remains limited. This study provides a comprehensive histological, immunohistochemical, lectin-histochemical, and ultrastructural characterization of the olfactory rosettes of S. senegalensis across multiple life stages, including premetamorphic larvae, fry, juveniles and adults. Although the olfactory organs undergo substantial structural changes following metamorphosis, differentiated and functionally active olfactory sensory neurons (OSNs) are already present in premetamorphic larvae. Subsequently, two epithelial regions were distinguished along the olfactory lamellae: a sensory epithelium containing abundant OSNs and supporting cells, and a nonsensory epithelium dominated by goblet and other secretory cells. Ciliated and microvillous OSNs were distinguished from 60 dph onward based on morphological and ultrastructural features and supported by immunoreactivity with CR, CB, Gγ8 and PGP. Crypt cells showed immunolabelling with S100, NSE and CYK8. Furthermore, lectin histochemistry revealed ontogenetic changes in epithelial glycoconjugates, with early diffuse binding patterns evolving into stratified and region-specific distributions. Overall, these results demonstrate the structural and functional complexity of the olfactory epithelium in S. senegalensis, significantly enriching the limited available morphological and neurochemical information on the species. Full article

Insect sex pheromone receptors (PRs) are crucial for regulating mating and reproduction. In the insect olfactory perception pathway, the pheromone-binding protein (PBP) facilitates the efficient translocation of sex pheromones, enabling them to bind to PRs. PRs convert chemical signals into electrical signals, which are transmitted to the insect central nervous system to ultimately regulate reproductive behaviors. Thus, conducting functional analysis of PRs not only clarifies the molecular mechanism underlying insect mating via sex pheromone recognition and reveals the intrinsic regulatory link between sex pheromone detection and mating behavior but also provides theoretical support for the scientific understanding of the insect olfactory system. Additionally, this research lays a core theoretical foundation for the development of green pest control technologies in agriculture and forestry. This paper systematically reviews the research methods, technical principles, and advantages and disadvantages of techniques used to study insect PR genes. It summarizes representative identified PRs and their corresponding research strategies, aiming to provide a reference for future investigations into insect chemical communication and for the advancement of pest control practices. Full article

Diverse epigenetic regulatory mechanisms ensure and modulate cellular diversity. The histone 3 lysine 9 me3 (H3K9me3) post-translational modification participates in silencing lineage-inappropriate genes by restricting access of transcription factors and other regulatory proteins to genes that control cell fate. Mouse olfactory sensory neurons (OSNs) select one olfactory receptor (OR) gene out of 2600 possibilities. This monoallelic and stochastic OR choice occurs as OSNs differentiate and undergo dramatic changes in nuclear architecture. OR genes from different chromosomes converge into specialized nuclear bodies and chromatin compartments, as H3K9me3 and chromatin binding proteins including heterochromatin protein 1 (HP1) are incorporated. In this work, we have uncovered an unexpected role for HP1β in OR choice and neuronal identity that cannot be rescued by HP1α in vivo. With the use of a conditional knock-in mouse model, that after CRE expression replaces HP1β with HP1α, we observe changes in H3K9me3 levels and DNA accessibility over OR gene clusters. These changes alter the expression patterns that partition the mouse olfactory epithelium into five OR expression zones, which results in a reduced OR repertoire that leads to a loss of olfactory sensory neuron diversity. We propose that HP1β modulates the competition of OR promoters for enhancers to promote receptor diversity by establishing repression gradients in a zonal fashion. Full article