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Journal of Insect Science (Online) May 2024Bactrocera tryoni (Froggatt) and Bactrocera neohumeralis (Hardy) are sibling fruit fly species that are sympatric over much of their ranges. Premating isolation of these...
Bactrocera tryoni (Froggatt) and Bactrocera neohumeralis (Hardy) are sibling fruit fly species that are sympatric over much of their ranges. Premating isolation of these close relatives is thought to be maintained in part by allochrony-mating activity in B. tryoni peaks at dusk, whereas in B. neohumeralis, it peaks earlier in the day. To ascertain whether differences in pheromone composition may also contribute to premating isolation between them, this study used solid-phase microextraction and gas chromatography-mass spectrometry to characterize the rectal gland volatiles of a recently collected and a more domesticated strain of each species. These glands are typical production sites and reservoirs of pheromones in bactrocerans. A total of 120 peaks were detected and 50 were identified. Differences were found in the composition of the rectal gland emissions between the sexes, species, and recently collected versus domesticated strains of each species. The compositional variation included several presence/absence and many quantitative differences. Species and strain differences in males included several relatively small alcohols, esters, and aliphatic amides. Species and strain differences in females also included some of the amides but additionally involved many fatty acid esters and 3 spiroacetals. While the strain differences indicate there is also heritable variation in rectal gland emissions within each species, the species differences imply that compositional differences in pheromones emitted from rectal glands could contribute to the premating isolation between B. tryoni and B. neohumeralis. The changes during domestication could also have significant implications for the efficacy of Sterile Insect Technique control programs.
Topics: Animals; Male; Female; Tephritidae; Pheromones; Sympatry; Gas Chromatography-Mass Spectrometry; Species Specificity; Reproductive Isolation; Sexual Behavior, Animal; Solid Phase Microextraction
PubMed: 38913610
DOI: 10.1093/jisesa/ieae066 -
ACS Omega Jun 2024Antimicrobial peptides (AMPs) are a type of biomaterial used against multidrug resistant (MDR) bacteria. This study reports the design of a peptide family rich in...
Antimicrobial peptides (AMPs) are a type of biomaterial used against multidrug resistant (MDR) bacteria. This study reports the design of a peptide family rich in tryptophan and lysine obtained by optimizing a natural AMP using single factor modification and pheromone hybridization to expedite the penetration and improve the antimicrobial activity of AMPs. S-4, L-4, and P-4 showed α-helical structures, exhibited extremely fast membrane penetration rates , and could kill MDR bacteria efficiently within 30 min. Intracellular fluorescence localization suggested rapid membrane-penetrating of AMPs within 1 min, making it more difficult for bacteria to develop resistance. Furthermore, they could effectively inhibit and destroy bacterial biofilms with dual antimicrobial and antibiofilm activity. In the treatment of skin infections caused by MDR- , AMPs could effectively alleviate inflammation without toxic side effects. Additionally, the triple antimicrobial damage of AMPs was described in detail. AMPs rapidly penetrate the cell membrane, inducing cell membrane damage, triggering oxidative damage with a storm of reactive oxygen species and leading to bacterial death through leakage of cellular contents by complexing with DNA. The multiple damage is an important means by which AMPs can prevent bacterial resistance adequately.
PubMed: 38911764
DOI: 10.1021/acsomega.4c01577 -
MSphere Jun 2024is an emerging human and animal pathogen. Functional studies of genes involved in virulence of and other pyogenic group streptococci are often hampered by limited...
UNLABELLED
is an emerging human and animal pathogen. Functional studies of genes involved in virulence of and other pyogenic group streptococci are often hampered by limited genetic tractability. It is known that pyogenic streptococci carry genes required for competence for natural transformation; however, in contrast to other streptococcal subgroups, there is limited evidence for gene transfer by natural transformation in these bacteria. In this study, we systematically assessed the genomes of 179 . strains of both human and animal origins (subsp. and respectively) for the presence of genes required for natural transformation. While a considerable fraction of the strains contained inactive genes, the majority (64.2%) of the strains had an intact gene set. In selected strains, we examined the dynamics of competence activation after addition of competence-inducing pheromones using transcriptional reporter assays and exploratory RNA-seq. Based on these findings, we were able to establish a protocol allowing us to utilize natural transformation to construct deletion mutants by allelic exchange in several strains of both subspecies. As part of the work, we deleted putative lactose utilization genes to study their role in growth on lactose. The data presented here provide new knowledge on the potential of horizonal gene transfer by natural transformation in and, importantly, demonstrates the possibility to exploit natural transformation for genetic engineering in these bacteria.
IMPORTANCE
Numerous spp. exchange genes horizontally through natural transformation, which also facilitates efficient genetic engineering in these organisms. However, for the pyogenic group of streptococci, including the emerging pathogen , there is limited experimental evidence for natural transformation. In this study, we demonstrate that natural transformation indeed is possible in strains under optimal conditions. We utilized this method to perform gene deletion through allelic exchange in several strains, thereby paving the way for more efficient gene engineering methods in pyogenic streptococci.
PubMed: 38904369
DOI: 10.1128/msphere.00214-24 -
International Journal of Molecular... May 2024The effect of pesticides on insects is often discussed in terms of acute and chronic toxicity, but an important and often overlooked aspect is the impact of sublethal... (Review)
Review
The effect of pesticides on insects is often discussed in terms of acute and chronic toxicity, but an important and often overlooked aspect is the impact of sublethal doses on insect physiology and behavior. Pesticides can influence various physiological parameters of insects, including the innate immune system, development, and reproduction, through a combination of direct effects on specific exposed tissues and the modification of behaviors that contribute to health and reproductive success. Such behaviors include mobility, feeding, oviposition, navigation, and the ability to detect pheromones. Pesticides also have a profound effect on insect learning and memory. The precise effects depend on many different factors, including the insect species, age, sex, caste, physiological condition, as well as the type and concentration of the active ingredients and the exposure route. More studies are needed to assess the effects of different active ingredients (and combinations thereof) on a wider range of species to understand how sublethal doses of pesticides can contribute to insect decline. This review reflects our current knowledge about sublethal effects of pesticides on insects and advancements in the development of innovative methods to detect them.
Topics: Animals; Insecta; Pesticides; Reproduction; Behavior, Animal
PubMed: 38892195
DOI: 10.3390/ijms25116007 -
Animals : An Open Access Journal From... May 2024Chemical communication is an important mode of communication in the courtship and breeding processes of amphibians. In caudates, multiple components of sexual pheromones...
Chemical communication is an important mode of communication in the courtship and breeding processes of amphibians. In caudates, multiple components of sexual pheromones have been identified and functionally verified. One of these pheromone systems is plethodontid modulating factor (PMF). In anurans, the pheromone called amplexin was found in nuptial pads of ranids and was considered a member of the PMF system, yet its bio-function has not been tested. In this study, we obtained 18 amplexin transcript sequences from nuptial pads of (Amphibia, Ranidae) by transcriptome sequencing and found that the proteins translated by these transcripts are diversified, hydrophilic, and relatively stable. We also acquired a amplexin isoform with the highest expression level in the transcriptome analysis through the prokaryotic expression system. Using two different animal behavioral experimental settings, we have tested the bio-function of the recombinant PMF protein (rPMF) in 's reproduction and found that the rPMF does not attract females but shortens the duration of amplexus significantly. This is the first study to verify the function of the PMF pheromone in Anura, indicating the pervasiveness of chemical communication during breeding in amphibians.
PubMed: 38891597
DOI: 10.3390/ani14111550 -
Animals : An Open Access Journal From... May 2024Although the presence of female contact sex pheromones in . has been hypothesized, to date its existence has not been proven. To gather more evidence of their...
Although the presence of female contact sex pheromones in . has been hypothesized, to date its existence has not been proven. To gather more evidence of their existence, cuticular liposoluble extracts were obtained from the following samples of adult females to be used as the experimental treatments: (1) ventral exoskeleton of immature female (VI), (2) dorsolateral exoskeleton of immature female (DI), (3) ventral exoskeleton of mature female (VM), and (4) dorsolateral exoskeleton of mature female (DM). Polyvinyl chloride tubes (artificial females; AF) were coated with each extract and the behavior displayed by sexually mature males in contact with the AF was recorded and classified as follows: 0 = no response; 1 = contact; 2 = pushing; and 3 = prolonged contact (≥10 s). To test the hypothesis that the extracts collected from the ventral portion of the abdomen exoskeleton have a higher effect on the behavior of males than the extracts collected from the dorsolateral portion of the abdomen exoskeleton, the experiment was divided into two bioassays: Bioassay I (VI vs. DI) and Bioassay II (VM vs. DM). In each bioassay, all experimental treatments were significantly different ( > 0.05) from the CTL group (AF coated with hexane). Notably, the pushing behavior was significantly higher ( < 0.05) in the VI treatment compared to the CTL and DI treatment. These results provide evidence of the existence of contact female sex pheromones with sexual recognition function located primarily in the ventral portion of the abdomen exoskeleton of . .
PubMed: 38891570
DOI: 10.3390/ani14111523 -
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 -
Science Advances Jun 2024Advanced social behavior, or eusociality, has been evolutionarily profound, allowing colonies of ants, termites, social wasps, and bees to dominate competitively over...
Advanced social behavior, or eusociality, has been evolutionarily profound, allowing colonies of ants, termites, social wasps, and bees to dominate competitively over solitary species throughout the Cenozoic. Advanced sociality requires not just nestmate cooperation and specialization but refined coordination and communication. Here, we provide independent evidence that 100-million-year-old Cretaceous ants in amber were social, based on chemosensory adaptations. Previous studies inferred fossil ant sociality from individual ants preserved adjacent to others. We analyzed several fossil ants for their antennal sensilla, using original rotation imaging of amber microinclusions, and found an array of antennal sensilla, specifically for alarm pheromone detection and nestmate recognition, sharing distinctive features with extant ants. Although Cretaceous ants were stem groups, the fossilized sensilla confirm hypotheses of their complex sociality.
Topics: Animals; Ants; Social Behavior; Animal Communication; Pheromones; Fossils; Behavior, Animal; Biological Evolution; Sensilla
PubMed: 38875342
DOI: 10.1126/sciadv.adp3623 -
MBio Jun 2024Mitogen-activated protein kinase (MAPK) pathways are fundamental to the regulation of biological processes in eukaryotic organisms. The basidiomycete , known for causing...
Mitogen-activated protein kinase (MAPK) pathways are fundamental to the regulation of biological processes in eukaryotic organisms. The basidiomycete , known for causing fungal meningitis worldwide, possesses five MAPKs. Among these, Cpk1, Hog1, and Mpk1 have established roles in sexual reproduction, stress responses, and cell wall integrity. However, the roles of Cpk2 and Mpk2 are less understood. Our study elucidates the functional interplay between the Cpk1/Cpk2 and Mpk1/Mpk2 MAPK pathways in . We discovered that overexpression compensates for Δ mating deficiencies via the Mat2 transcription factor, revealing functional redundancy between Cpk1 and Cpk2. We also found that Mpk2 is phosphorylated in response to cell wall stress, a process regulated by the MAPK kinase (MAP2K) Mkk2 and MAP2K kinases (MAP3Ks) Ssk2 and Ste11. Overexpression of partially restores cell wall integrity in Δ by influencing key cell wall components, such as chitin and the polysaccharide capsule. Contrarily, overexpression cannot restore thermotolerance and cell membrane integrity in Δ. These results suggest that Mpk1 and Mpk2 have redundant and opposing roles in the cellular response to cell wall and membrane stresses. Most notably, the dual deletion of and restores wild-type mating efficiency in Δ mutants via upregulation of the mating-regulating transcription factors and , suggesting that the Mpk1 and Mpk2 cooperate to negatively regulate the pheromone-responsive Cpk1 MAPK pathway. Our research collectively underscores a sophisticated regulatory network of cryptococcal MAPK signaling pathways that intricately govern sexual reproduction and cell wall integrity, thereby controlling fungal development and pathogenicity.IMPORTANCEIn the realm of fungal biology, our study on offers pivotal insights into the roles of specific proteins called mitogen-activated protein kinases (MAPKs). Here, we discovered the cryptic functions of Cpk2 and Mpk2, two MAPKs previously overshadowed by their dominant counterparts Cpk1 and Mpk1, respectively. Our findings reveal that these "underdog" proteins are not just backup players; they play crucial roles in vital processes like mating and cell wall maintenance in . Their ability to step in and compensate when their dominant counterparts are absent showcases the adaptability of . This newfound understanding not only enriches our knowledge of fungal MAPK mechanisms but also underscores the intricate balance and interplay of proteins in ensuring the organism's survival and adaptability.
PubMed: 38874410
DOI: 10.1128/mbio.01156-24 -
BMC Plant Biology Jun 2024Allelopathy is a biological process in which one organism releases biochemicals that affect the growth and development of other organisms. The current investigation...
Allelopathic effect of the methanol extract of the weed species-red sorrel (Rumex acetosella L.) on the growth, phytohormone content and antioxidant activity of the cover crop - white clover (Trifolium repens L.).
Allelopathy is a biological process in which one organism releases biochemicals that affect the growth and development of other organisms. The current investigation sought to determine the allelopathic effect of Rumex acetosella on white clover (Trifolium repens) growth and development by using its shoot extract (lower IC value) as a foliar treatment. Here, different concentrations (25, 50, 100, and 200 g/L) of shoot extract from Rumex acetosella were used as treatments. With increasing concentrations of shoot extract, the plant growth parameters, chlorophyll and total protein content of Trifolium repens decreased. On the other hand, ROS, such as O and HO and antioxidant enzymes, including SOD, CAT, and POD, increased with increasing shoot extract concentration. A phytohormonal study indicated that increased treatment concentrations increased ABA and SA levels while JA levels were reduced. For the identification of allelochemicals, liquid‒liquid extraction, thin-layer chromatography, and open-column chromatography were conducted using R. acetosella shoot extracts, followed by a seed bioassay on the separated layer. A lower IC value was obtained through GC/MS analysis. gammaSitosterol was identified as the most abundant component. The shoot extract of Rumex acetosella has strong allelochemical properties that may significantly impede the growth and development of Trifolium repens. This approach could help to understand the competitive abilities of this weed species and in further research provide an alternate weed management strategy.
Topics: Trifolium; Plant Extracts; Antioxidants; Allelopathy; Rumex; Plant Growth Regulators; Methanol; Plant Weeds; Pheromones; Plant Shoots
PubMed: 38853237
DOI: 10.1186/s12870-024-05240-z