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Molecular Neurobiology Aug 2023Normal aging and many age-related disorders such as Alzheimer's disease cause deficits in olfaction; however, it is currently unknown how natural and pathological aging...
Normal aging and many age-related disorders such as Alzheimer's disease cause deficits in olfaction; however, it is currently unknown how natural and pathological aging impacts the detection of social odors which might contribute to the impoverishment of social behavior at old age further worsening overall health. Analysis of the vomeronasal organ, the main gateway to pheromone-encoded information, indicated that natural and pathological aging distinctively affects the neurogenic ability of the vomeronasal sensory epithelium. Whereas cell proliferation remained majorly preserved in 1-year-old APP/PS1 mice, naturally aged animals exhibited significant deficiencies in the number of mature, proliferative, and progenitor cells. These alterations may support age-related deficits in the recognition of social cues and the display of social behavior. Our findings indicate that aging disrupts the processing of social olfactory cues decreasing social odor exploration, discrimination, and habituation in both wild-type senescent (2-year-old) mice and in 1-year-old double mutant model of Alzheimer's disease (APP/PS1). Furthermore, social novelty was diminished in 1-year-old APP/PS1 mice, indicating that alterations in the processing of social cues are accelerated during pathological aging. This study reveals fundamental differences in the cellular processes by which natural and pathological aging disrupts the exploration of social information and social behavior.
Topics: Mice; Animals; Alzheimer Disease; Pheromones; Social Behavior; Smell; Aging; Mice, Transgenic; Amyloid beta-Protein Precursor; Disease Models, Animal
PubMed: 37129797
DOI: 10.1007/s12035-023-03362-3 -
Chronic Stress (Thousand Oaks, Calif.) 2023Social isolation (SI) and loneliness are major adult and adolescent health concerns, particularly in the coronavirus disease 2019 (COVID-19) era. Recent prospective...
Social isolation (SI) and loneliness are major adult and adolescent health concerns, particularly in the coronavirus disease 2019 (COVID-19) era. Recent prospective cohort studies indicate that older women who experienced both SI and loneliness had a significantly higher risk of cardiovascular disease (CVD). Hypertension, a well-established risk factor for CVD, is more prevalent in elderly women than men. Furthermore, a lack of social relationships is strongly associated with an increased risk of hypertension in middle-aged and elderly women compared to men. Although this has not been extensively studied, adolescents and young adults who experience loneliness or SI may also be at risk for CVD and depression. The purpose of this study was to examine the effect of SI on blood pressure and depression-like behavior in young male and female mice. Weaned C57BL/6 mice were randomly assigned ( = 6/group/sex) to either group housing (GH) or SI. Animals in the SI group were housed in individual cages for 8 weeks with no view of other animals. The cages were kept in ventilated racks to prevent pheromone exposure and socially isolated animals had no cage enrichment. SI increased systolic, diastolic, and mean arterial blood pressure in females and elevated heart rate in both sexes. Body weight gain was dramatically increased in socially isolated females but tended to decrease in socially isolated males. In the forced swim test, which detects depression-like behavior, there was no difference between groups in total immobility time. The latency to immobility, however, was significantly decreased in socially isolated females. Serum concentrations of corticosterone and metanephrine did not differ between socially isolated and group-housed females, but corticosterone levels were significantly reduced in socially isolated males. Our results indicate that 8 weeks of SI leads to significant changes in blood pressure and heart rate and mild changes in depression-like behavior in young mice, with females affected more than males.
PubMed: 37859939
DOI: 10.1177/24705470231207010 -
European Journal of Protistology Jun 2024In Euplotes, protein pheromones regulate cell reproduction and mating by binding cells in autocrine or heterologous fashion, respectively. Pheromone binding sites...
In Euplotes, protein pheromones regulate cell reproduction and mating by binding cells in autocrine or heterologous fashion, respectively. Pheromone binding sites (receptors) are identified with membrane-bound pheromone isoforms determined by the same genes specifying the soluble forms, establishing a structural equivalence in each cell type between the two twin proteins. Based on this equivalence, autocrine and heterologous pheromone/receptor interactions were investigated analyzing how native molecules of pheromones Er-1 and Er-13, distinctive of mating compatible E. raikovi cell types, associate into crystals. Er-1 and Er-13 crystals are equally formed by molecules that associate cooperatively into oligomeric chains rigorously taking a mutually opposite orientation, and each burying two interfaces. A minor interface is pheromone-specific, while a major one is common in Er-1 and Er-13 crystals. A close structural inspection of this interface suggests that it may be used by Er-1 and Er-13 to associate into heterodimers, yet inapt to further associate into higher complexes. Pheromone-molecule homo-oligomerization into chains accounts for clustering and internalization of autocrine pheromone/receptor complexes in growing cells, while the heterodimer unsuitability to oligomerize may explain why heterologous pheromone/receptor complexes fail clustering and internalization. Remaining on the cell surface, they are credited with a key role in cell-cell mating adhesion.
Topics: Pheromones; Euplotes; Protozoan Proteins; Protein Multimerization; Protein Binding; Autocrine Communication; Receptors, Pheromone
PubMed: 38520753
DOI: 10.1016/j.ejop.2024.126075 -
The ISME Journal Oct 2023Sex pheromones are widely used by insects as a reproductive isolating mechanism to attract conspecifics and repel heterospecifics. Although researchers have obtained...
Sex pheromones are widely used by insects as a reproductive isolating mechanism to attract conspecifics and repel heterospecifics. Although researchers have obtained extensive knowledge about sex pheromones, little is known about the differentiation mechanism of sex pheromones in closely related species. Using Bactrocera dorsalis and Bactrocera cucurbitae as the study model, we investigated how the male-borne sex pheromones are different. The results demonstrated that both 2,3,5-trimethylpyrazine (TMP) and 2,3,5,6-tetramethylpyrazine (TTMP) were sex pheromones produced by rectal Bacillus in the two flies. However, the TMP/TTMP ratios were reversed, indicating sex pheromone specificity in the two flies. Bacterial fermentation results showed that different threonine and glycine levels were responsible for the preference of rectal Bacillus to produce TMP or TTMP. Accordingly, threonine (glycine) levels and the expression of the threonine and glycine coding genes were significantly different between B. dorsalis and B. cucurbitae. In vivo assays confirmed that increased rectal glycine and threonine levels by amino acid feeding could significantly decrease the TMP/TTMP ratios and result in significantly decreased mating abilities in the studied flies. Meanwhile, decreased rectal glycine and threonine levels due to RNAi of the glycine and threonine coding genes was found to significantly increase the TMP/TTMP ratios and result in significantly decreased mating abilities. The study contributes to the new insight that insects and their symbionts can jointly regulate sex pheromone specificity in insects, and in turn, this helps us to better understand how the evolution of chemical communication affects speciation.
Topics: Male; Animals; Sex Attractants; Amino Acids; Tephritidae; Glycine; Threonine; Bacteria; Bacillus
PubMed: 37550382
DOI: 10.1038/s41396-023-01488-9 -
BioRxiv : the Preprint Server For... Sep 2023Identifying a mate is a central imperative for males of most species but poses the challenge of distinguishing a suitable partner from an array of potential male...
Identifying a mate is a central imperative for males of most species but poses the challenge of distinguishing a suitable partner from an array of potential male competitors or females of related species. Mate recognition systems are thus subject to strong selective pressures, driving the rapid coevolution of female sensory cues and male sensory preferences. Here we leverage the rapid evolution of female pheromones across the genus to gain insight into how males coordinately adapt their detection and interpretation of these chemical cues to hone their mating strategies. While in some species females produce unique pheromones that act to attract and arouse their conspecific males, the pheromones of most species are sexually monomorphic such that females possess no distinguishing chemosensory signatures that males can use for mate recognition. By comparing several close and distantly-related species, we reveal that males have evolved the distinct ability to use a sexually-monomorphic pheromone, 7-tricosene (7-T), as an excitatory cue to promote courtship, a sensory innovation that enables males to court in the dark thereby expanding their reproductive opportunities. To gain insight into the neural adaptations that enable 7-T to act as an excitatory cue, we compared the functional properties of two key nodes within the pheromone circuits of and a subset of its closest relatives. We show that the instructive role of 7-T in arises from concurrent peripheral and central circuit changes: a distinct subpopulation of sensory neurons has acquired sensitivity to 7-T which in turn selectively signals to a distinct subset of P1 neurons in the central brain that trigger courtship behaviors. Such a modular circuit organization, in which different sensory inputs can independently couple to multiple parallel courtship control nodes, may facilitate the evolution of mate recognition systems by allowing males to take advantage of novel sensory modalities to become aroused. Together, our findings suggest how peripheral and central circuit adaptations can be flexibly linked to underlie the rapid evolution of mate recognition and courtship strategies across species.
PubMed: 37745588
DOI: 10.1101/2023.09.16.558080 -
BioRxiv : the Preprint Server For... Nov 2023Molecular tool development in traditionally non-tractable animals opens new avenues to study gene functions in the relevant ecological context. Entomopathogenic...
Molecular tool development in traditionally non-tractable animals opens new avenues to study gene functions in the relevant ecological context. Entomopathogenic nematodes (EPN) and their symbiotic bacteria of spp are a valuable experimental system in the laboratory and are applicable in the field to promote agricultural productivity. The infective juvenile (IJ) stage of the nematode packages mutualistic symbiotic bacteria in the intestinal pocket and invades insects that are agricultural pests. The lack of consistent and heritable genetics tools in EPN targeted mutagenesis severely restricted the study of molecular mechanisms underlying both parasitic and mutualistic interactions. Here, I report a protocol for CRISPR-Cas9 based genome-editing that is successful in two EPN species, and . I adapted a gonadal microinjection technique in , which created on-target modifications of a homologue (cuticular collagen) by homology-directed repair. A similar delivery approach was used to introduce various alleles in including and (a muscle gene), resulting in visible and heritable phenotypes of dumpy and twitching, respectively. Using conditionally dominant alleles of as a co-CRISPR marker, I successfully modified a second locus encoding Sh-Daf-22 (a homologue of human sterol carrier protein SCPx), predicted to function as a core enzyme in the biosynthesis of nematode pheromone that is required for IJ development. As a proof of concept, null mutant showed IJ developmental defects ( . This research demonstrates that spp are highly tractable for targeted mutagenesis and has great potential in the study of gene functions under controlled laboratory conditions within the relevant context of its ecological niche.
PubMed: 38045388
DOI: 10.1101/2023.11.24.568619 -
Animals : An Open Access Journal From... Nov 2023There is a recent growing interest in the study of evolutionary and behavioral ecology of amphibians. Among salamanders, Plethodontidae is the most speciose family, with... (Review)
Review
There is a recent growing interest in the study of evolutionary and behavioral ecology of amphibians. Among salamanders, Plethodontidae is the most speciose family, with more than 500 species, while in Europe, there are only 8 species, all belonging to the genus . European plethodontids recently received increasing attention with regard to the study of their natural history, ecology and behavior; however, the lack of standardized data, especially for the latter, hampers comparative analysis with the species from the New World. We here synthetized the recent advances in behavioral ecology, considering as a starting point the comprehensive monography of Lanza and colleagues published in 2006. We identified the behavioral categories that were investigated the most, but we also highlighted knowledge gaps and provided directions for future studies. By reviewing the scientific literature published within the period 2006-2022, we observed a significant increase in the number of published articles on behavior, overall obtaining 36 articles. Behavioral studies on focused mainly on trophic behavior (42%), and on intraspecific behavior (33%), while studies on pheromonal communication and interspecific behavioral interactions were lacking. In addition, most of the studies were observational (83%), while the experimental method was rarely used. After providing a synthesis of the current knowledge, we suggest some relevant topics that need to be considered in future research on the behavioral ecology of European plethodontids, highlighting the importance of a more integrative approach in which both field observations and planned experiments are used.
PubMed: 38067018
DOI: 10.3390/ani13233667 -
Journal of Advanced Research May 2024In sub-Saharan Africa, the invasive South American leafminer Phthorimaea absoluta is the most damaging tomato pest. Females of the pest can reproduce both sexually and...
INTRODUCTION
In sub-Saharan Africa, the invasive South American leafminer Phthorimaea absoluta is the most damaging tomato pest. Females of the pest can reproduce both sexually and through parthenogenesis and lay their eggs on all tomato plant parts. The mirid predator Nesidiocoris tenuis, a biological control agent for the pest, is also a tomato pest when prey population is low. To date, however, no study has developed an eco-friendly solution that targets both the predator and its host in a tomato farming system.
OBJECTIVE
To develop a bio-based management system for both pest and predator based on the combined use of sexual communication in the predator and visual cues.
METHODS
We collected volatiles from both sexes of the Kenyan population of the predator N. tenuis and identified candidate sex pheromone components by coupled gas chromatography-mass spectrometry (GC-MS). We used electrophysiological assays to identify antennally-active odorants in the volatiles, followed by field trials with different pheromone-baited colored traps to validate the responses of both predator and prey. Thereafter, we compared the reflectance spectra of the colored traps with those of different tomato plant tissues.
RESULTS
Our results reveal an interplay between different sensory cues which in the predator-prey interaction may favor the predator. Antennae of both sexes of predator and prey detect the predator sex pheromone identified as 1-octanol and hexyl hexanoate. Unexpectedly, our field experiments led to the discovery of a lure for P. absoluta females, which were lured distinctly into a pheromone-baited trap whose reflectance spectrum mimicked that of ripe tomato fruit (long wavelength), an egg-laying site for females. Contrastingly, N. tenuis males were lured into baited white trap (short wavelength) when the predator is actively searching for prey.
CONCLUSION
Our results demonstrate the novel use of a predator sex pheromone and different visual cues to assess complex trophic interactions on tomatoes.
PubMed: 38710469
DOI: 10.1016/j.jare.2024.05.005 -
BMC Biology May 2024Populations of the plant pathogenic fungus Verticillium dahliae display a complex and rich genetic diversity, yet the existence of sexual reproduction in the fungus...
BACKGROUND
Populations of the plant pathogenic fungus Verticillium dahliae display a complex and rich genetic diversity, yet the existence of sexual reproduction in the fungus remains contested. As pivotal genes, MAT genes play a crucial role in regulating cell differentiation, morphological development, and mating of compatible cells. However, the functions of the two mating type genes in V. dahliae, VdMAT1-1-1, and VdMAT1-2-1, remain poorly understood.
RESULTS
In this study, we confirmed that the MAT loci in V. dahliae are highly conserved, including both VdMAT1-1-1 and VdMAT1-2-1 which share high collinearity. The conserved core transcription factor encoded by the two MAT loci may facilitate the regulation of pheromone precursor and pheromone receptor genes by directly binding to their promoter regions. Additionally, peptide activity assays demonstrated that the signal peptide of the pheromone VdPpg1 possessed secretory activity, while VdPpg2, lacked a predicted signal peptide. Chemotactic growth assays revealed that V. dahliae senses and grows towards the pheromones FO-a and FO-α of Fusarium oxysporum, as well as towards VdPpg2 of V. dahliae, but not in response to VdPpg1. The findings herein also revealed that VdMAT1-1-1 and VdMAT1-2-1 regulate vegetative growth, carbon source utilization, and resistance to stressors in V. dahliae, while negatively regulating virulence.
CONCLUSIONS
These findings underscore the potential roles of VdMAT1-1-1 and VdMAT1-2-1 in sexual reproduction and confirm their involvement in various asexual processes of V. dahliae, offering novel insights into the functions of mating type genes in this species.
Topics: Genes, Mating Type, Fungal; Ascomycota; Pheromones; Fungal Proteins; Verticillium
PubMed: 38714997
DOI: 10.1186/s12915-024-01900-6