Search Results (113)

Background: Gustatory dysfunction represents an underrecognized complication that may influence dietary behaviors and metabolic control. Previous investigations have suggested alterations in taste in patients with diabetes, yet the relationship between disease duration and specific taste modalities remains incompletely characterized. Aim: This study aimed to (i) compare orosensory detection thresholds for lipid and sweet tastes between patients with recent type 2 diabetes mellitus (rT2DM) (duration ≤ 5 years) and chronic type 2 diabetes mellitus (cT2DM) (duration > 5 years), and (ii) determine whether diabetes duration is associated with alterations in chemosensory function in a North African population. Methods: A cross-sectional comparative pilot study was conducted at the National Institute of Nutrition and Food Technology in Tunis, Tunisia, from April to June 2021. Sixty-seven patients with type 2 diabetes mellitus (T2DM) receiving oral antidiabetic medication were recruited through systematic sampling and divided into two groups: rT2DM (n = 30, duration ≤ 5 years) and cT2DM (n = 37, duration > 5 years). Orosensory detection thresholds for lipid taste were assessed using eight ascending concentrations of linoleic acid ranging from 0.018 to 12 mmol/L. In contrast, sweet taste thresholds were evaluated using a sucrose concentration series ranging from 0.01 to 5 mmol/L. The three-alternative forced-choice method with an ascending-concentration presentation was employed for both taste modalities. Detection thresholds were defined as the lowest concentration at which participants correctly identified the taste quality. Results: Patients with cT2DM exhibited significantly elevated orosensory detection thresholds compared to those with rT2DM for both taste modalities tested. The median linoleic acid detection threshold was 6.000 mmol/L in cT2DM versus 0.058 mmol/L in rT2DM (p < 0.001), representing a 107-fold increase in detection threshold. For sweet taste, the median sucrose detection threshold was 1.0 mmol/L in cT2DM compared with 0.5 mmol/L in rT2DM (p < 0.001), indicating a 2-fold increase in the threshold. In the overall patient cohort, the duration of diabetes was positively correlated with both fat taste perception thresholds (r = 0.657, p < 0.001) and sweet taste perception thresholds (r = 0.466, p < 0.001). However, when analyses were performed by diabetes duration-based subgroups, these correlations were observed only for fat taste perception in cT2DM, with no statistically significant correlations found in rT2DM. In multivariate linear regression analyses adjusted for age, body mass index, and sex/gender, the duration of diabetes remained independently associated with fat and sweet taste perception. Conclusions: Extended T2DM duration is associated with substantial elevations in orosensory detection thresholds for both lipid and sweet tastes in a North African population. These findings suggest that disease chronicity may contribute to chemosensory impairment, potentially influencing dietary preferences and metabolic control in patients with diabetes. Full article

Background and Objectives: Japan’s aging population faces growing challenges related to oral frailty, a condition characterized by the decline of oral function associated with physical and nutritional deterioration. Impaired oral function contributes to reduced chewing, swallowing, and saliva secretion, leading to poor appetite and frailty progression. Ninjin’yoeito (NYT), a traditional Kampo formula, has been clinically used to improve systemic weakness and oral symptoms. This study aimed to evaluate the efficacy and safety of NYT in improving oral health among elderly individuals with impaired oral function. Materials and Methods: In this open-label prospective study, patients received NYT daily for 12 weeks. Assessments included oral symptom scores, mucosal moisture, repetitive saliva swallowing tests (RSST), gustatory function by visual analogue scale (VAS), an 11-item oral questionnaire, and immune profiling by flow cytometry. Safety was assessed through hematological and biochemical tests. Results: Symptom scores decreased from 8.27 at baseline to 3.64 at 12 weeks (p = 0.006), while oral condition scores improved from 5.09 to 1.36 (p = 0.006). Mucosal moisture increased (25.1 to 28.1, p = 0.03), and RSST frequency improved (2.18 to 4.55, p = 0.046). Questionnaire scores declined from 5.1 to 2.0 (p < 0.001). VAS-taste was unchanged overall (p = 0.21) but improved in low baseline patients. Laboratory findings showed no adverse changes, with favorable lipid trends. Immune analysis revealed a decline in NKG2D expression (p = 0.02), whereas other activating and inhibitory markers remained stable. Conclusions: NYT was well tolerated and associated with gradual improvements in oral and physical symptoms among elderly individuals with impaired oral function. These findings provide preliminary evidence supporting the feasibility of Kampo-based approaches for maintaining oral health in aging populations and warrant further validation in larger controlled trials. Full article

The red flower aphid (Uroleucon gobonis) is a significant agricultural pest causing damage via direct feeding and virus transmission. Chemical sensory proteins (CSPs) are critical for insecticide resistance, mediating the detection of semiochemicals or the sequestration of neuroactive insecticides. This study provides the first comprehensive identification and functional characterization of chemosensory gene families in Uroleucon gobonis to elucidate their roles in chemoperception and resistance. We conducted de novo transcriptome sequencing and assembly to identify chemosensory genes. Their phylogenetic relationships and structural motifs were analyzed. Developmental expression patterns were assessed via RNA-seq, and tissue-specific expression was validated using quantitative real-time PCR (qRT-PCR). We identified 40 chemosensory genes: 12 odorant-binding proteins (OBPs), 8 CSPs, 14 odorant receptors (ORs), and 6 gustatory receptors (GRs). Phylogenetic analysis revealed species-specific adaptations, including the absence of GR clades 2/4 and minimal representation in CSP Subgroup III. Structural motifs were highly conserved in ORs/OBPs but divergent in CSPs/GRs. RNA-seq identified 1896 differentially expressed genes (DEGs) between instars, including stage-specific regulation of UgobCSP4, UgobCSP6, UgobOBP3, and UgobOBP10. qRT-PCR confirmed extreme spatial expression, such as leg-specific UgobCSP6 and antennae-specific UgobOBP10. These findings elucidate key molecular adaptations in chemosensory gene families governing perception and potential insecticide resistance in Uroleucon gobonis. The identified stage- and tissue-specific genes provide targets for developing species-specific pest control strategies. Full article

Insects rely heavily on olfaction to regulate essential behaviors such as host location, oviposition and mating. The invasive cotton mealybug, Phenacoccus solenopsis Tinsley represents a global threat to cotton and numerous cultivated crops. To elucidate the molecular basis of its olfaction mechanisms, we sequenced and assembled antennal transcriptomes from male and female adults using Illumina NovaSeq X Plus technology. Among 13,891 unigenes, 91 chemosensory genes were identified, including 40 odorant receptors, 13 gustatory receptors, 19 ionotropic receptors, 10 odorant-binding proteins, 7 chemosensory proteins, and 2 sensory neuron membrane proteins. Differential expression analysis revealed 6312 genes with significant sex-biased expression between male and female antennae, including 55 chemosensory genes. Phylogenetic analyses further clarified the evolutionary relationships of these chemosensory genes with homologs from other hemipteran species. Notably, validation confirmed that 18 PsolORs were male-biased. This comprehensive transcriptomic study establishes a foundation for further functional characterization of pheromone reception and provides valuable candidate genes for dissecting chemoreception mechanisms in P. solenopsis. Full article

Anastatus orientalis, a prominent egg parasitoid of Lycorma delicatula, demonstrates considerable potential for biological control. A. orientalis is dependent on host volatiles to identify and locate appropriate hosts for reproduction, with its olfactory system playing a vital role in volatile detection. There is little known about the chemosensory genes in A. orientalis. Therefore, here, we conducted a transcriptome analysis of the males and females from A. orientalis. Overall, 24 odorant binding proteins (OBPs), 4 chemosensory proteins (CSPs), 26 odorant receptors (ORs), 3 gustatory receptors (GRs), 3 ionotropic receptors (IRs), and 2 sensory neuron membrane proteins (SNMPs) were identified by transcriptome analysis. The values for fragments per kilobase per million (FPKM) indicated that the chemosensory protein gene families in A. orientalis exhibit different expression levels in male and female adults, with some genes showing significant differences and displaying sex-biased expression. Furthermore, RACE technology, phylogenetic analysis, and expression analysis were used to investigate the role that AoOBP8 plays in olfaction in A. orientalis. AoOBP8 was highly expressed in females and the heads of adults, indicating that the gene has a crucial role to play in the search for hosts and in oviposition in female adults, while the head is crucial in recognizing chemical information. These results contribute to a deeper understanding of the functions of chemosensory protein gene families in A. orientalis and offer a reference for developing biocontrol methods for forestry pests. Full article

Background/Objectives: Sensory-specific satiety (SSS) refers to the decrease in pleasantness of a food after repeated consumption, while other foods remain appealing. Despite its significance in hedonic food perception, the underlying mechanisms of SSS remain poorly understood. This study aimed to investigate the neurobiological basis of SSS and its relationship with body weight and hedonic food perception. Methods: Twenty-three healthy individuals with varying body weights underwent functional magnetic resonance imaging during a novel gustatory stimulation procedure. SSS was induced by repeated exposure to glucose, during which the hedonic perception of a neutral stimulus increased. Results: We found that SSS was associated with a network of brain regions related to reward and taste processing, including the lateral orbitofrontal cortex. Increased activation in the medial prefrontal cortex was related to both the expectation and receipt of a neutral stimulus with increased hedonic value during SSS. Finally, higher body weight was related to decreased activation in the medial prefrontal cortex, whereas an increased tendency for food craving was associated with increased activation of the lateral orbitofrontal cortex during SSS. Conclusions: Our results extend previous findings of an orbitofrontal-cortex-mediated shift in hedonic perception of food during SSS and show that the medial prefrontal cortex plays a crucial role in reward value modulation during SSS. Furthermore, our results indicate that increased BMI and trait food craving are associated with altered reward processing during SSS. Taken together, our results provide new insights into the neural mechanisms underlying changes in hedonic food perception during SSS. Full article

Notonectidae belongs to the infraorder Nepomorpha within the order Hemiptera. The aim of this study was to analyze the morphological types and arrangement of leg sensilla in Anisops, Enithares and Notonecta. A variety of sensilla are distributed on the legs. These sensilla are responsible for receiving signals from the external environment. Mechanoreceptors exhibit the highest diversity. Using a scanning electron microscope, ten types of sensilla were identified on the legs of seventeen species from Notonectidae. Basic types of mechanoreceptors, including sensilla trichodea (ST1, ST2), sensilla chaetica (SCh1, SCh2), sensilla basiconica (SB2) and sensilla campaniformia (SCa), were distributed across all the studied species. In Anisops, sensilla arch-shaped (SAr) and sensilla spoon-shaped (SSp) were reported for the first time. Additionally, six subtypes of ST were distinguished in Anisops, among which ST3, ST4, ST5 and ST6 are unique. In Enithares and Notonecta, sensilla styloconica (SS) were observed; these sensilla are hypothesized to function as both mechanoreceptors and gustatory receptors. Beyond mechanoreceptors, we also identified thermo-hygroreceptors—sensilla ampullacea (SA) and sensilla coeloconica (SCo)—as well as a potential olfactory sensilla type, namely, sensilla placodea multilobated (SPM). These findings suggest that Notonectidae leg sensilla play an important role in the perception of aquatic environments and prey localization. Full article

This study presents detailed microstructural observations of the mouthparts and sensory organs of adult cicadomorphan species, obtained using scanning electron microscopy (SEM). Despite microstructural variation, the overall morphology of the mouthparts, comprising a three-segmented labium and a bundle of interlocking stylets (maxillae and mandibles), is highly conserved across species, supporting its evolutionary significance in sap feeding from floem, xylem, or epidermis cells. Variations in the number and shape of mandibular stylet barbs likely reflect adaptations to different host plant tissues. The presence of an identical dual interlocking system between the maxillary stylets, which is found consistently across taxa, enhances functional stability during feeding and indicates a conserved mechanism among cicadomorphans. The species studied exhibit two distinct types of salivary canal closure: hooked and T-shaped. The latter potentially represents a state linked to specialised feeding strategies, such as sap xylem feeding. On the labial tip, there are different shapes of the anterior sensory fields. This area hosts a complex array of sensilla of different numbers, including gustatory (sensilla peg, PS1 and PS2, basiconica, BS3, double basiconica, DB), olfactory (finger–like, FLS) and thermo-hygroreceptive (sensillum dome-shaped, DS, and coeloconicum, CS) types, which facilitate host detection and feeding site selection. In the posterior sensory field, sensilla contact-chemosensory (sensilla basiconica, BS1 and BS2, and sensillum trichoideum, TS) are present. Mechanosensilla chaetica (CH1–CH3) are widely distributed on the last labial segment and may contribute to labium positioning. These findings emphasise the presence of both conserved and specialised morphological traits reflecting evolutionary and ecological diversification within Cicadomorpha. Full article

The greater wax moth Galleria mellonella (Lepidoptera: Galleriinae) represents a ubiquitous apicultural pest that poses significant threats to global beekeeping industries. The larvae damage honeybee colonies by consuming wax combs and tunneling through brood frames, consequently destroying critical hive infrastructure including brood-rearing areas, honey storage cells, and pollen reserves. Larval feeding behavior is critically dependent on chemosensory input for host recognition and food selection. In this study, we conducted a transcriptome analysis of larval heads and bodies in G. mellonella. We identified a total of 25 chemosensory genes: 9 odorant binding proteins (OBPs), 1 chemosensory protein (CSP), 5 odorant receptors (ORs), 4 gustatory receptors (GRs), 4 ionotropic receptors (IRs) and 2 sensory neuron membrane proteins (SNMPs). TPM normalization was employed to assess differential expression patterns of chemosensory genes between heads and bodies. Nine putative chemosensory genes were detected as differentially expressed, suggesting their potential functional roles. Subsequently, we quantified expression dynamics via reverse transcription quantitative PCR in major chemosensory tissues (larval heads, adult male and female antennae), revealing adult antennal-biased expression for most chemosensory genes in G. mellonella. Notably, two novel candidates (GmelOBP22 and GmelSNMP3) exhibited particularly high expression in larval heads, suggesting their crucial functional roles in larval development and survival. These findings enhance our understanding of the chemosensory mechanisms in G. mellonella larvae and establish a critical foundation for future functional investigations into its olfactory mechanisms. Full article

Tomicus pilifer is a major pest that threatens Pinus koraiensis forests in the northeast region of China. In this study, we employed scanning electron microscopy (SEM) to observe the sensilla on the antennae, mouthparts, and legs of both male and female T. pilifer adults, analyzing the differences in sensillum types, external morphology, and quantities between sexes. The results revealed six types of sensilla on the antennae of both males and females, including sensilla trichoidea, sensilla zigzag, sensilla coeloconica, sensilla chaetica, Böhm bristles, and sensilla basiconica. Among these, sensilla basiconica was the most abundant, with four subtypes identified, and sensilla basiconica III was observed only on the male antennae, indicating sexual dimorphism in sensillum types. The mouthparts exhibited the greatest diversity in sensilla, with seven types identified: sensilla basiconica, sensilla twig basiconica, sensilla coeloconica, sensilla trichoidea, sensilla chaetica, sensilla zigzag, and sensilla digitiformia. Of these, sensilla basiconica and sensilla twig basiconica, responsible for olfactory or gustatory functions, were concentrated at the distal ends of the maxillary palps and labial palps. On the legs, sensilla trichoidea, sensilla zigzag, and sensilla chaetica were distributed on all segments. The findings of this study provide a scientific basis for further research into the olfactory and feeding behaviors, as well as electrophysiological studies, of T. pilifer. Full article

With the growing use of anti-obesity medications (AOMs), particularly glucagon-like peptide-1 (GLP-1) receptor agonists, interest in their impact on chemosensory function has increased. We report a case of subjective olfactory discomfort that developed during AOM therapy despite normal objective test results. A 41-year-old woman received the GLP-1 receptor agonist semaglutide for 24 weeks. Thorough olfactory function evaluation was performed using the Questionnaire of Olfactory Disorders (a validated questionnaire), the Yonsei Olfactory Function Test (for psychophysical testing), and chemical gustometry. The tests were performed before treatment and after 24 weeks of AOM therapy. At baseline, the patient had no olfactory complaints and showed normal test results. After treatment, she reported significant subjective olfactory discomfort (visual analog scale score: 48, maximum: 50), with decreased quality of life and parosmia, despite stable Yonsei Olfactory Function scores and normal gustatory function. This case highlights the possible mismatch between subjective and objective olfactory assessment during AOM therapy. Comprehensive chemosensory evaluations and interdisciplinary collaboration are essential, and further large-scale long-term studies are required. Full article

Goji berry is widely consumed worldwide and holds substantial market value, yet its cultivation faces significant threats from the goji berry psyllid (Bactericera gobica). Chemosensory-related genes play critical roles in regulating insect behaviors, which makes them key molecular targets for the development of environmentally friendly pest control strategies. However, chemosensory genes in B. gobica have not been previously identified or characterized. In this study, we sequenced transcriptomes from the antennae and body tissues of male and female B. gobica and annotated genes associated with chemosensory functions. We identified 15 odorant-binding proteins (OBPs), 18 chemosensory proteins (CSPs), 3 sensory neuron membrane proteins (SNMPs), 26 odorant receptors (ORs), 8 gustatory receptors (GRs), and 32 ionotropic receptors (IRs). Transcriptome data and a quantitative real-time PCR confirmed the tissue-specific expression patterns of these genes, with several genes, including three BgobOBPs, eight BgobCSPs, one BgobOR, two BgobGRs, and two BgobIR, highly expressed in the antennae, suggesting their role in olfactory recognition. BgobGR1 was most highly expressed among GRs, indicating its important role in gustatory perception. We also identified gene BgobGR5 with differential expression patterns between females and males. Our study represents the first characterization of chemosensory genes in a Bactericera species. Full article

Background/Objectives: Taste dysfunction is a highly prevalent yet underrecognized complication among patients with head and neck cancer (HNC), significantly impairing nutritional intake, treatment adherence, and quality of life (QoL). This comprehensive review synthesizes current knowledge on the pathophysiological mechanisms and clinical management of taste dysfunction associated with HNC and its treatments, particularly chemotherapy and radiotherapy. Methods: A structured literature search was performed across PubMed, Scopus, and Cochrane Library for articles published between January 2015 and February 2025. Studies were included if they investigated taste dysfunction related to HNC, focusing on pathophysiological mechanisms and therapeutic interventions. A total of 47 original studies were analyzed through a narrative synthesis due to heterogeneity in study designs and outcomes. Results: Taste dysfunction in HNC patients arises from tumor-related inflammation, cytotoxic injury from chemotherapy, and radiation-induced epithelial and neural damage. Chemotherapy and radiotherapy often exert synergistic negative effects on gustatory function. Management strategies identified include dietary counselling, nutritional supplementation (zinc, lactoferrin, monosodium glutamate, miraculin), pharmacological agents targeting salivary function, and non-pharmacological interventions such as acupuncture, photobiomodulation, and reconstructive surgery. However, the evidence is limited by small sample sizes, methodological variability, and the frequent exclusion of HNC patients from broader dysgeusia trials. Reported prevalence of taste dysfunction ranged from 39% to 97.4%, with higher rates observed among patients treated with radiotherapy and chemoradiotherapy. Conclusions: Taste dysfunction remains a critical yet unmet clinical challenge in HNC patients. High-quality, targeted research is urgently needed to develop standardized assessments and evidence-based management strategies to improve patient outcomes. Full article

The brown planthopper (BPH), Nilaparvata lugens, is the most destructive insect pest of rice. BPH infestations severely threaten rice yield worldwide. The gustatory receptor NlGr23 plays a critical role in mediating the repulsive reaction to oxalic acid of the BPH. We integrated transcriptomic and proteomic analyses to determine the metabolic and behavioral consequences of NlGr23 silencing. The RNAi-mediated knockdown of NlGr23 increased body weight and honeydew production, indicating enhanced feeding activity. The results of multiomics profiling revealed disrupted lipid homeostasis, identifying 187 differentially expressed genes and 150 differentially expressed proteins. These genes were enriched in pathways including glycerophospholipid metabolism, fatty acid biosynthesis, and AMPK signaling. The results of biochemical assays showed that NlGr23 silencing elevated triacylglycerol levels by 68.83%, and reduced glycerol and free fatty acid levels, suggesting impaired lipolysis. The NlGr23 loss-of-function mutation mechanistically activates the AMPK pathway, suppresses lipid breakdown, and promotes energy storage. This study established NlGr23 as a key regulator linking chemosensation to metabolic reprogramming, providing new insights into gustatory receptor-mediated energy homeostasis in the BPH. Full article

The mechanisms of chemoreception in fig wasps (Hymenoptera, Agaonidae) are of primary importance in their co-evolutionary relationship with the fig trees they pollinate. As the supplementary receptors to odorant receptors (ORs) and gustatory receptors (GRs) in insects, we compare the evolutionary characters of ionotropic receptors (IRs) among 25 fig wasp taxa in six genera. In total, we identified 205 IRs in 25 fig wasps, with each taxon recording from 5 to 12 IR genes. We found 189 IR genes clustered into 18 orthologous groups that can be divided into three types: IRco, antennal IRs, and divergent IRs. More IRs belong to antennal IRs in fig wasps, which can be sensitive to acids, aldehydes, polyamines, salt, amino acids, and temperature/humidity according to homology comparison. Additionally, some IR genes in fig wasps do not cluster with those of outgroup species (e.g., Drosophila melanogaster, Apis mellifera), suggesting they may represent a unique group and may have special functions in fig wasps. Divergent IRs are very few, with large sequence variation between species. Compared to ORs and GRs in fig wasps, gene sequences in most IR orthologous groups are more conserved between genera, with the lowest sequence similarity in 10 orthologous groups (including three IRco) exhibiting above 58.5%. Gene sequences are consistent with the phylogenetic relationships among fig wasps, which is the same as ORs and GRs. Strong purifying selection of IR genes was detected, as shown by the low ω values. Signatures of positive selection were detected in loci from three orthologous groups. Our results provide important molecular information for further studies on chemosensory mechanisms in fig wasps. Full article