The Science of Nature最新文献

The search for effective alternatives to conventional acaricides has positioned lithium as a promising experimental candidate for controlling Varroa destructor; however, its physiological impact on the honeybee (Apis mellifera) remains insufficiently characterized. This study evaluated the chronic oral toxicity of lithium citrate over a 10-day exposure period, focusing on survival, midgut histopathological changes, and gut microbiota dynamics. Newly emerged bees were exposed to sugar syrup containing 12.5, 25, and 50 mM lithium citrate. Mortality increased monotonically with dose: 10-day survival was 0.94 in the control and 0.84, 0.22, and 0 at 12.5, 25, and 50 mM, respectively (all pairwise contrasts significant, Benjamini-Hochberg correction). Histological analysis of the midgut revealed pronounced epithelial damage, characterized by severe desquamation and cellular shedding into the lumen, even at the lower dose of 12.5 mM, with the highest severity at 12.5 mM rather than 25 mM; the peritrophic membrane remained intact in all groups. Furthermore, 16S rRNA gene sequencing revealed variation in the relative abundance of several core gut bacteria across treatment groups, although neither alpha- nor beta-diversity differed significantly among groups. At the highest lithium concentration (25 mM), Gilliamella showed a markedly lower median relative abundance, whereas Frischella was relatively more abundant; however, these patterns were not statistically supported by differential abundance analysis and did not indicate a consistent concentration-dependent response. Given the limited number of biological replicates (n = 3 per group), these compositional patterns should be regarded as preliminary. These findings suggest that lithium citrate, despite its varroacidal potential, acts as a significant physiological stressor, compromising the structural integrity of the digestive tract and disrupting microbial homeostasis. Consequently, the development of lithium-based treatments must carefully consider both lethal and sublethal effects at the individual level, and colony-level consequences remain to be evaluated.

Climate change poses complex and unpredictable challenges to the ecosystems and agricultural systems. Anthropogenic activities have increased CO₂ concentrations in the atmosphere and changes in ultraviolet-B (UV-B) radiation. These environmental changes severely impair crop growth and production of crops, particularly in sensitive species. Therefore, evaluating the combined effects of eCO₂ and UV-B radiation is essential for predicting climate change on crop systems and ecosystem stability. The aim of this experiment was to evaluate the tolerance of two Moringa species (Moringa oleifera and Moringa peregrina) to elevated (eCO₂), UV-B radiation and their combined effects. The results revealed that Moringa oleifera under eCO₂ treatment had higher plant height than Moringa peregrina. On the other hand, the lowest plant height was recorded in both tested species under UV-B radiation treatment. Further, chlorophyll a, chlorophyll b, and carotenoid content in Moringa oleifera were much higher in eCO₂-treated plants than in Moringa peregrina, although UV-B radiation had a significant impact on reducing photosynthetic pigments in both species. The nutrient analysis also revealed that the levels of nitrogen (N), magnesium (Mg), calcium (Ca) and boron (B) in Moringa oleifera were significantly higher than those in Moringa peregrina under eCO₂ treatment. Conversely, the concentrations of potassium (K), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and sulfur (S) were found to be greatest in the Moringa peregrina under eCO₂ treatment.

Plant-mediated synthesis of silver nanoparticles (AgNPs) represents an emerging bioinspired strategy for generating multifunctional nanomaterials by exploiting natural phytochemicals as reducing and stabilizing agents. In this study, Barleria lawii leaf extract was utilized for the first time as a biological platform for the synthesis of silver nanoparticles (Bl-AgNPs). Phytochemical analysis revealed substantial phenolic and flavonoid contents (28.4 mg GAE/g and 18.1 mg QE/g, respectively), supporting their role in Ag⁺ reduction and nanoparticle stabilization. Under optimized conditions (10 mM AgNO₃, extract-to-precursor ratio of 1:2, pH 8, and 60 °C), stable spherical Bl-AgNPs were obtained, exhibiting a characteristic surface plasmon resonance band at 422.5 nm. XRD analysis confirmed face-centered cubic crystallinity with an average crystallite size of 27.60 ± 6.57 nm, while TEM revealed spherical particles with an average size of 22.1 ± 6.5 nm. DLS gave a hydrodynamic diameter of 121.8 nm, and zeta potential measurements indicated good colloidal stability (− 31.2 mV). The synthesized Bl-AgNPs demonstrated enhanced antioxidant activity (DPPH IC₅₀ = 17.24 µg/mL), broad-spectrum antibacterial activity against Staphylococcus aureus, Escherichia coli, and Bacillus altitudinis (inhibition zones of 30.5, 25.5, and 26.5 mm, respectively, at 500 µg/mL), and increased cytotoxicity against MCF-7 breast cancer cells (IC₅₀ = 12.95 µg/mL) compared with the crude extract (IC₅₀ = 40.57 µg/mL). Additionally, Bl-AgNPs exhibited efficient catalytic performance in NaBH₄-mediated reduction of 4-nitrophenol and methylene blue, following pseudo-first-order kinetics. Overall, this study highlights B. lawii as an underexplored phytochemical resource for the bioinspired generation of stable and multifunctional silver nanoparticles, demonstrating the potential of plant-derived metabolites in developing biologically active nanomaterials.

Graphical abstract

Workflow depicting the green biosynthesis of Bl-AgNPs using Barleria lawii leaf extract, highlighting extract preparation, phytochemical-mediated nanoparticle formation, physicochemical characterization, and evaluation of antimicrobial, antioxidant, cytotoxic, and catalytic activities.

Ectoparasites often exploit anatomical weak points in their hosts, yet how their attacks are distributed across the body remains poorly understood in armored ectotherms and other organisms partly due to scarce data and the lack of spatial tools for studying parasitism on complex surfaces. This study combines citizen-science imagery with three-dimensional kernel density estimation (3D KDE) to examine 275 tabanid biting events on Melanosuchus niger, mapped onto a high-resolution 3D anatomical model. Contrary to expectations, bite intensity was unrelated to surface exposure; instead, attacks clustered in nasal and orbital regions. These findings reveal non-random, anatomy-driven parasitism and introduce a replicable spatial framework for quantifying host–parasite interactions using open-access data and morphological modeling. This complementary approach advances the ecological understanding of microhabitat selection in ectoparasites and provides new tools for exploring fine-scale interactions in elusive or logistically constrained systems.

Termites respond to spores of pathogenic fungi that have adhered to the cuticle with brief bouts of rapid shaking, an alarm response that promotes allogrooming, which helps prevent fatal infections. The pathogen associated molecular pattern (PAMP) that elicits this proactive hygienic response is unknown. Ergosterol, an important component of the fungal cell membrane, has been identified as a potential PAMP in the subterranean termite Coptotermes formosansus. In this study, commercial or extracted ergosterol elicited a hygienic behavioral response in workers of the subterranean termite Reticulitermes flavipes. The ergosterol content of pathogenic spores of Metarhizium spp. were also found to vary among different strains and species of the fungus. However, there was a significant positive correlation between ergosterol content of different Metarhizium isolates and fatal infections caused by their spores (conidia). Alarm responses from challenges with conidia were not positively correlated with estimates of ergosterol content and instead were negatively correlated with ergosterol content although not significantly, which does not support the hypothesis that ergosterol is a critical recognition cue for the hygienic response. Termicin, an antifungal peptide in termite salivary secretions, was also most effective against the most lethal isolates, which had the highest ergosterol content. Ergosterol appears to influence spore membrane vulnerability to disruption by the antifungal peptide. Overall, our results indicate ergosterol influences both the vulnerability of Metarhizium conidia to termicin and the detection of an unidentified PAMP, which alerts termites to fungal contamination. This sets up a potential trade-off for the fungus between a shield for protection and signal for detection: reducing vulnerability to termicin by decreasing the content of cell membrane ergosterol results in an increase in a cell wall PAMP that termites can recognize and respond to with allogrooming. Reticulitermes spp. appear to have adaptively exploited this trade-off.

Biological rhythms regulate insect activity and represent a conserved adaptive trait across life forms. Understanding the behavioral rhythms of dispersive cryptic species is important for elucidating their ecological interactions and improving pest management strategies. In this study, we investigated the diel patterns of emergence and flight activity of the bamboo borer Dinoderus minutus under field and laboratory conditions using a chronobiological approach. Field emergence was evaluated using emergence cages containing naturally infested bamboo culms, whereas flight activity was monitored using semiochemical-baited cross-vane panel traps. In laboratory assays, locomotor and flight activities were compared between morning and afternoon periods. Periodicity analyses revealed significant daily rhythms in both emergence and flight activity. Cosinor analyses indicated that most individuals emerged around 14:00 h and initiated flight shortly thereafter, at around 16:00 h, which corresponded to the acrophase of each behavior. No emergence or dispersal activity was recorded during the night period, indicating strictly diurnal dispersal behavior. Laboratory experiments corroborated field observations, showing significantly greater flight initiation, locomotor activity, velocity, and distance traveled during the mid-afternoon than in the morning. These results demonstrate that D. minutus exhibits a predictable behavioral periodicity, with peak emergence and flight activity concentrated during the mid-afternoon. This information provides an important basis for field monitoring, detection, and the development of pest management strategies targeting bamboo borer populations.

Background

Facial soft tissue thickness (FSTT) represents a key parameter in forensic facial reconstruction and human identification, reflecting both biological and behavioral influences. This pilot cross-sectional study examined the impact of body mass index, age and smoking status on FSTT in a Slovak adult population, with emphasis on sex-specific variations.

Methods

A total of 246 participants (176 females, 70 males) were measured using B-mode ultrasonography across eight midline facial landmarks and eight paired bilateral landmarks. Statistical analyses included non-parametric tests, Spearman rank correlation and general linear models with BMI and age as covariates.

Results

Sex-specific patterns were identified. In females, BMI was the dominant predictor, showing medium to large effects across most landmarks. Age contributed modestly to variation, particularly in the lower face. Smoking related differences were localized, rather than consistent across facial landmarks. Female conventional smokers showed lower FSTT values than non-smokers at the left fossa canina landmark (p = 0.046). In males, age showed a stronger and more consistent association with FSTT than BMI, with age-related variation most evident in midfacial and mandibular regions. Direct comparison between smokers and non-smokers in males revealed no significant differences in FSTT at any landmark. Overall smoking status was not consistently associated with FSTT.

Conclusions

The findings highlight sex specific and anatomical variability in FSTT and provide population specific data relevant for forensic facial reconstruction. Larger and more balanced samples are needed to confirm these preliminary associations.