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International Journal of Molecular... Jul 2023Olfactory receptors (ORs), key components in ensuring the detection of myriad odorants, are expressed not only on the surface of olfactory neurons but also in many other...
Olfactory receptors (ORs), key components in ensuring the detection of myriad odorants, are expressed not only on the surface of olfactory neurons but also in many other tissues. In the case of ORs expressed at the sperm membrane, in vitro experiments with human and mouse spermatozoids have shown that they move toward the regions with the highest concentration of bourgeonal and lyral, respectively. However, to date, no in vivo experiment has shown any biological function of these ORs. To demonstrate a possible role in vivo of ORs in sperm chemotaxis, we overloaded the vaginal space of female mice from the prolific Swiss CD1 strain with lyral to induce competition with the supposed natural ligand and to prevent its detection. As shown, the mice that received lyral had much fewer newborns than the control mice treated with PBS, showing that lyral has a strong negative impact on procreation. This indicates that the ORs at the sperm surface are biologically active and make an important contribution to reproduction. Control experiments performed with hexanal, which does not alter sperm movement in vitro, indicate that the inhibition of reproduction observed was specific to lyral. In addition, we show that males are attracted to the smell of lyral, which acts as a pheromone, and prefer to copulate with mice marked on their back with lyral rather than with those that have not been marked. These results suggest an explanation for some cases of human infertility, which could result from an absence of recognition between the natural ligand and the ORs, either due to a mutation or a lack of expression from one of the two partners, allowing for the development of a diagnostic tests. These results might also lead to the development of a novel contraception strategy based on the use of vaginal tablets delivering an odorant or a drug that competes with the natural ligand.
Topics: Infant, Newborn; Humans; Male; Mice; Female; Animals; Receptors, Odorant; Ligands; Semen; Spermatozoa; Odorants; Reproduction; Olfactory Receptor Neurons
PubMed: 37511035
DOI: 10.3390/ijms241411277 -
Current Biology : CB Jun 2024While the neural basis of age-related decline has been extensively studied, less is known about changes in neural function during the pre-senescent stages of adulthood....
While the neural basis of age-related decline has been extensively studied, less is known about changes in neural function during the pre-senescent stages of adulthood. Adult neural plasticity is likely a key factor in social insect age polyethism, where individuals perform different tasks as they age and divide labor in an age-dependent manner. Primarily, workers transition from nursing to foraging tasks, become more aggressive, and more readily display alarm behavior as they get older. While it is unknown how these behavioral dynamics are neurally regulated, they could partially be generated by altered salience of behaviorally relevant stimuli. Here, we investigated how odor coding in the antennal lobe (AL) changes with age in the context of alarm pheromone communication in the clonal raider ant (Ooceraea biroi). Similar to other social insects, older ants responded more rapidly to alarm pheromones, the chemical signals for danger. Using whole-AL calcium imaging, we then mapped odor representations for five general odorants and two alarm pheromones in young and old ants. Alarm pheromones were represented sparsely at all ages. However, alarm pheromone responses within individual glomeruli changed with age, either increasing or decreasing. Only two glomeruli became sensitized to alarm pheromones with age, while at the same time becoming desensitized to general odorants. Our results suggest that the heightened response to alarm pheromones in older ants occurs via increased sensitivity in these two core glomeruli, illustrating the importance of sensory modulation in social insect division of labor and age-associated behavioral plasticity.
PubMed: 38876103
DOI: 10.1016/j.cub.2024.05.031 -
Stress Biology Jul 2023The devastating wheat stripe (yellow) rust pathogen, Puccinia striiformis f. sp. tritici (Pst), is a macrocyclic and heteroecious fungus. Pst produces urediniospores and...
High-throughput RNA sequencing reveals differences between the transcriptomes of the five spore forms of Puccinia striiformis f. sp. tritici, the wheat stripe rust pathogen.
The devastating wheat stripe (yellow) rust pathogen, Puccinia striiformis f. sp. tritici (Pst), is a macrocyclic and heteroecious fungus. Pst produces urediniospores and teliospores on its primary host, wheat, and pycniospores and aeciospores are produced on its alternate hosts, barberry (Berberis spp.) or mahonia (Mahonia spp.). Basidiospores are developed from teliospores and infect alternate hosts. These five spore forms play distinct roles in Pst infection, disease development, and fungal survival, etc. However, the specific genes and mechanisms underlying these functional differences are largely unknown. In this study, we performed, for the first time in rust fungi, the deep RNA sequencing to examine the transcriptomic shift among all five Pst spore forms. Among a total of 29,591 identified transcripts, 951 were specifically expressed in basidiospores, whereas 920, 761, 266, and 110 were specific for teliospores, pycniospores, aeciospores, and urediniospores, respectively. Additionally, transcriptomes of sexual spores, namely pycniospores and basidiospores, showed significant differences from those of asexual spores (urediniospores, teliospores, and aeciospores), and transcriptomes of urediniospores and aeciospores were more similar to each other than to the three other spore forms. Especially, the basidiospores and pycniospores which infected the berberis shows wide differences in the cell wall degrading-enzymes and mating and pheromone response genes. Besides, we also found that there are 6234 differential expressed genes between the urediniospores and pycniospores, while only have 3 genes have alternative splicing enents, suggesting that differential genes expression may make more contribution than AS. This comprehensive transcriptome profiling can substantially improve our understanding of the developmental biology of the wheat stripe rust fungus.
PubMed: 37676525
DOI: 10.1007/s44154-023-00107-z -
BioRxiv : the Preprint Server For... Feb 2024While the neural basis of age-related decline has been extensively studied (1-3), less is known about changes in neural function during the pre-senescent stages of...
While the neural basis of age-related decline has been extensively studied (1-3), less is known about changes in neural function during the pre-senescent stages of adulthood. Adult neural plasticity is likely a key factor in social insect age polyethism, where individuals perform different tasks as they age and divide labor in an age-dependent manner (4-9). Primarily, workers transition from nursing to foraging tasks (5, 10), become more aggressive, and more readily display alarm behavior (11-16) as they get older. While it is unknown how these behavioral dynamics are neurally regulated, they could partially be generated by altered salience of behaviorally relevant stimuli (4, 6, 7). Here, we investigated how odor coding in the antennal lobe (AL) changes with age in the context of alarm pheromone communication in the clonal raider ant () (17). Similar to other social insects (11, 12, 16), older ants responded more rapidly to alarm pheromones, the chemical signals for danger. Using whole-AL calcium imaging (18), we then mapped odor representations for five general odorants and two alarm pheromones in young and old ants. Alarm pheromones were represented sparsely at all ages. However, alarm pheromone responses within individual glomeruli changed with age, either increasing or decreasing. Only two glomeruli became sensitized to alarm pheromones with age, while at the same time becoming desensitized to general odorants. Our results suggest that the heightened response to alarm pheromones in older ants occurs via increased sensitivity in these two core glomeruli, illustrating the importance of sensory modulation in social insect division of labor and age-associated behavioral plasticity.
PubMed: 38405746
DOI: 10.1101/2024.02.13.580193 -
PloS One 2023Scratching the environment is a natural behaviour that cats use for communication and physical maintenance purposes, however when it is carried out on household... (Randomized Controlled Trial)
Randomized Controlled Trial
Scratching the environment is a natural behaviour that cats use for communication and physical maintenance purposes, however when it is carried out on household furniture it is considered unacceptable for some owners and even grounds for relinquishment of cats. The objective of this study was to investigate the efficacy of FELIWAY® Classic Diffuser in reducing undesirable scratching (scratching vertical surfaces indoors other than the scratching post) in cats. A 28 day, randomised, triple-blind, placebo-controlled study with a total of 1060 caregiver-cat dyads was conducted. The study contained two groups: the Pheromone Group consisted of caregivers who were given a pheromone diffuser (n = 546) and the Placebo Group consisted of caregivers who were given a placebo diffuser (n = 514). A questionnaire with three subsections was distributed online. The first section, completed by the respondents at day 0, inquired about the cats' daily routines, social and physical environments, behaviour, temperament, and emotional states. The second section filled on day 0, 7, 14, and 28, assessed the Frequency and the Intensity of the undesirable scratching problem and the effectiveness of the product. The last section, filled on the 28th day of the product application, related to the caregivers' opinions about the product and overall outcome. After 28 days the scratching Frequency reduced for 83.5% of the cats in the Pheromone Group and 68.5% for the Placebo Group (p<0.0001). The Intensity was significantly different between treatment groups at D7 (p = 0.0170), at D14 (p = 0.0189) and at D28 (p<0.001). The reduction of the Global Index Score, which was calculated by multiplying the Intensity with the Frequency, was significantly higher for the Pheromone Group (p<0.001). This study provides direct evidence that the use of FELIWAY® Classic diffuser significantly reduces the Frequency, Intensity and the Global Index Score of undesirable scratching.
Topics: Animals; Cats; Behavior, Animal; Pheromones; Surveys and Questionnaires; Humans
PubMed: 37851638
DOI: 10.1371/journal.pone.0292188 -
Scientific Reports Oct 2023Population density is known to affect the health and survival of many species, and is especially important for social animals. In mice, living in crowded conditions...
Population density is known to affect the health and survival of many species, and is especially important for social animals. In mice, living in crowded conditions results in the disruption of social interactions, chronic stress, and immune and reproductive suppression; however, the underlying mechanisms remain unclear. Here, we investigated the role of chemosignals in the regulation of mouse physiology and behavior in response to social crowding. The pheromone 2,5-dimethylpyrazine (2,5-DMP), which is released by female mice in crowded conditions, induced aversion, glucocorticoid elevation and, when chronic, resulted in reproductive and immune suppression. 2,5-DMP olfaction induced genome destabilization in bone marrow cells in a stress-dependent manner, providing a plausible mechanism for crowding-induced immune dysfunction. Interestingly, the genome-destabilizing effect of 2,5-DMP was comparable to a potent mouse stressor (immobilization), and both stressors led to correlated expression changes in genes regulating cellular stress response. Thus, our findings demonstrate that, in mice, the health effects of crowding may be explained at least in part by chemosignals and also propose a significant role of stress and genome destabilization in the emergence of crowding effects.
Topics: Mice; Male; Female; Animals; Pheromones; Crowding; Reproduction; Population Density; Genomic Instability
PubMed: 37848549
DOI: 10.1038/s41598-023-44647-w -
Frontiers in Molecular Biosciences 2023-bark beetles are natural components and key ecological agents of coniferous forests. They spend most of their lives under the bark, where they are exposed to highly...
-bark beetles are natural components and key ecological agents of coniferous forests. They spend most of their lives under the bark, where they are exposed to highly toxic terpenes present in the oleoresin. Cytochrome P450 (CYP) is a multigene family involved in the detoxification of these compounds. It has been demonstrated that CYP6DE and CYP6DJ subfamilies hydroxylate monoterpenes, whose derivatives can act as pheromone synergist compounds or be pheromones themselves in these insects. Given the diversity and functional role of CYPs, we investigated whether these cytochromes have retained their function throughout the evolution of these insects. To test this hypothesis, we performed a Bayesian phylogenetic analysis to determine phylogenetic subgroups of cytochromes in these subfamilies. Subgroups were mapped and reconciled with the phylogeny. Molecular docking analyses were performed with the cytochromes of each subgroup and enantiomers of -pinene and -pinene, (+)-3-carene, -myrcene and -(+)-limonene. In addition, functional divergence analysis was performed to identify critical amino acid sites that influence changes in catalytic site conformation and/or protein folding. Three and two phylogenetic subgroups were recovered for the CYP6DE and CYP6DJ subfamilies, respectively. Mapping and reconciliation analysis showed different gain and loss patterns for cytochromes of each subgroup. Functional predictions indicated that the cytochromes analyzed are able to hydroxylate all monoterpenes; however, they showed preferential affinities to different monoterpenes. Functional divergence analyses indicated that the CYP6DE subfamily has experimented type I and II divergence, whereas the CYP6DJ subfamily has evolved under strong functional constraints. Results suggest cytochromes of the CYP6DE subfamily evolve to reinforce their detoxifying capacity hydroxylating mainly - and -pinene to (+) and (-)--verbenol, being the negative enantiomer used as a pheromone by several species; whereas cytochromes of the CYP6DJ subfamily appear to retain their original function related to the detoxification of these compounds.
PubMed: 37877122
DOI: 10.3389/fmolb.2023.1274838 -
Insect Biochemistry and Molecular... Nov 2023The order Isopoda contains both aquatic and terrestrial species, among which Hemilepistus reaumurii, which lives in arid environments and is the most adapted to...
The order Isopoda contains both aquatic and terrestrial species, among which Hemilepistus reaumurii, which lives in arid environments and is the most adapted to terrestrial life. Olfaction has been deeply investigated in insects while it has received very limited attention in other arthropods, particularly in terrestrial crustaceans. In insects, soluble proteins belonging to two main families, Odorant Binding Proteins (OBPs) and Chemosensory Proteins (CSPs), are contained in the olfactory sensillar lymph and are suggested to act as carriers of hydrophobic semiochemicals to or from membrane-bound olfactory receptors. Other protein families, namely Nieman-Pick type 2 (NPC2) and Lipocalins (LCNs) have been also reported as putative odorant carriers in insects and other arthropod clades. In this study, we have sequenced and analysed the transcriptomes of antennae and of the first pair of legs of H. reaumurii focusing on soluble olfactory proteins. Interestingly, we have found 13 genes encoding CSPs, whose sequences differ from those of the other arthropod clades, including non-isopod crustaceans, for the presence of two additional cysteine residues, besides the four conserved ones. Binding assays on two of these proteins showed strong affinities for fatty acids and long-chain unsaturated esters and aldehydes, putative semiochemicals for this species.
Topics: Animals; Pheromones; Isopoda; Insecta; Transcriptome; Smell; Insect Proteins; Arthropods; Receptors, Odorant; Arthropod Antennae; Phylogeny; Gene Expression Profiling
PubMed: 37743031
DOI: 10.1016/j.ibmb.2023.104012 -
The Science of the Total Environment Jul 2023Histamine is a component of the bed bug aggregation pheromone. It was recently identified as an environmental contaminant in homes with active bed bug infestations,...
Histamine is a component of the bed bug aggregation pheromone. It was recently identified as an environmental contaminant in homes with active bed bug infestations, posing a potential health risk to humans via skin contact or inhalation. It remains unclear how histamine is distributed in homes and if histamine can become airborne. In the present study, histamine levels in household dust were quantified from multiple locations within bed bug infested and uninfested apartments. Bed bug population levels were quantified using both traps and visual counts. The amount of histamine detected varied significantly with respect to sampling location, with the highest concentration of histamine quantified from bedding material. Infestation severity did not have a significant effect on histamine quantified at any location. Our results indicate that the bedroom should be the primary focus of histamine mitigation efforts, although histamine can be found throughout the home. Histamine quantified from homes without active bed bug infestations suggests that histamine from previous infestations can persist following pest eradication. These findings highlight the importance of histamine as a potential insect allergen and will be important for the development of targeted mitigation strategies of bed bug histamine.
Topics: Humans; Animals; Insect Control; Bedbugs; Histamine
PubMed: 37001661
DOI: 10.1016/j.scitotenv.2023.163180 -
Animals : An Open Access Journal From... Oct 2023It is estimated that 2 million domestic animals travel on commercial flights every year in the US alone and that dogs make up 58% of pets travelling worldwide. There has...
It is estimated that 2 million domestic animals travel on commercial flights every year in the US alone and that dogs make up 58% of pets travelling worldwide. There has been little research on the welfare effects of air travel on dogs. The purpose of this owner-reported study was to understand how well dogs cope with and recover from air travel from a physical, mental, and emotional health perspective. An online survey questionnaire was distributed globally to pet owners whose dogs had travelled by air in the last 12 months, and the results were collected and analysed. Information was received about dog and owner demographics, logistics, and preparation for travel, as well as the dog's experience of air travel. Results showed that most dogs cope with and recover well from air travel but that there is a group of individuals who suffer physical, mental, and emotional ill health consequences during or after air travel, including death. Stress management products such as anxiolytic medication, supplements, and pheromones were underutilised and, in some instances, actively discouraged. More education of all stakeholders of pet air travel is needed to improve the physical, mental, and emotional health and welfare of canine air travellers.
PubMed: 37835699
DOI: 10.3390/ani13193093