Combined exposure to microplastics and copper elicited size-dependent uptake and toxicity responses in red swamp crayfish (Procambarus clarkia)

In recent years, the toxicity of microplastics (MPs) in combination with heavy metals, particularly the influence of varying microplastic sizes on their toxic effects, has attracted widespread attention. In this study, red swamp crayfish (Procambarus clarkia) were exposed to MPs of two particle sizes (S-MPs: 5 μm, 1 mg/L; and L-MPs: 100 μm, 1 mg/L) and Cu (5 mg/L) individually or in combination for 96 h. The accumulation patterns of MPs were as follows: gills > intestines > hepatopancreas > muscles. Moreover, the accumulation pattern of Cu was as follows: intestines > gills > hepatopancreas > muscle. Additionally, S-MPs and L-MPs enhanced Cu accumulation, with the highest levels observed in the S-MPs+Cu-treated group. Histopathological analysis showed that the combined exposure led to greater hepatopancreatic damage. Assessment of antioxidant enzymes showed decreased activities of superoxide dismutase, catalase, and glutathione among the different treatments, except for malondialdehyde, which was elevated compared to the control group. In the S-MPs+Cu-treated group, the expression levels of Cu homeostasis genes (MTF-1, ATP2, Atox1, MT) were significantly lower than those in the Cu treated group. This study provides a valuable reference for studying the combined toxic effects of MPs with varying particle sizes on heavy metals.

Does death drive the scaling of life?

The magnitude of many kinds of biological structures and processes scale with organismal size, often in regular ways that can be described by power functions. Traditionally, many of these "biological scaling" relationships have been explained based on internal geometric, physical, and energetic constraints according to universal natural laws, such as the "surface law" and "3/4-power law". However, during the last three decades it has become increasingly apparent that biological scaling relationships vary greatly in response to various external (environmental) factors. In this review, I propose and provide several lines of evidence supporting a new ecological perspective that I call the "mortality theory of ecology" (MorTE). According to this viewpoint, mortality imposes time limits on the growth, development, and reproduction of organisms. Accordingly, small, vulnerable organisms subject to high mortality due to predation and other environmental hazards have evolved faster, shorter lives than larger, more protected organisms. A MorTE also includes various corollary, size-related internal and external causative factors (e.g. intraspecific resource competition, geometric surface area to volume effects on resource supply/transport and the protection of internal tissues from environmental hazards, internal homeostatic regulatory systems, incidence of pathogens and parasites, etc.) that impact the scaling of life. A mortality-centred approach successfully predicts the ranges of body-mass scaling slopes observed for many kinds of biological and ecological traits. Furthermore, I argue that mortality rate should be considered the ultimate (evolutionary) driver of the scaling of life, that is expressed in the context of other proximate (functional) drivers such as information-based biological regulation and spatial (geometric) and energetic (metabolic) constraints.

ArtSymbioCyc, a metabolic network database collection dedicated to arthropod symbioses: a case study, the tripartite cooperation in Sipha maydis

Most arthropods live in close association with bacteria. The genomes of associated partners have co-evolved, creating situations of interdependence that are complex to decipher despite the availability of their complete sequences. We developed ArtSymbioCyc, a metabolism-oriented database collection gathering genomic resources for arthropods and their associated bacteria. ArtSymbioCyc uses the powerful tools of the BioCyc community to produce high-quality annotations and to analyze and compare metabolic networks on a genome-wide scale. We used ArtSymbioCyc to study the case of the tripartite symbiosis of the cereal aphid Sipha maydis focusing on amino acid and vitamin metabolisms, as these compounds are known to be important in this strictly phloemophagous insect. We showed that the metabolic pathways of the insect host and its two obligate bacterial associates are interdependent and specialized in the exploitation of Poaceae phloem, particularly for the biosynthesis of sulfur-containing amino acids and most vitamins. This demonstrates that ArtSymbioCyc does not only reveal the individual metabolic capacities of each partner and their respective contributions to the holobiont they constitute but also allows to predict the essential inputs that must come from host nutrition.IMPORTANCEThe evolution has driven the emergence of complex arthropod-microbe symbiotic systems, whose metabolic integration is difficult to unravel. With its user-friendly interface, ArtSymbioCyc (https://artsymbiocyc.cycadsys.org) eases and speeds up the analysis of metabolic networks by enabling precise inference of compound exchanges between associated partners and helps unveil the adaptive potential of arthropods in contexts such as conservation or agricultural control.

A novel method for estimating pathogen presence, prevalence, load, and dynamics at multiple scales

The use of quantitative real-time PCR (qPCR) to monitor pathogens is common; however, quantitative frameworks that consider the observation process, dynamics in pathogen presence, and pathogen load are lacking. This can be problematic in the early stages of disease progression, where low level detections may be treated as 'inconclusive' and excluded from analyses. Alternatively, a framework that accounts for imperfect detection would provide more robust inferences. To better estimate pathogen dynamics, we developed a hierarchical multi-scale dynamic occupancy hurdle model (MS-DOHM). The model used data gathered during sampling for Pseudogymnoascus destructans (Pd), the causative agent of white-nose syndrome, a fungal disease that has cause severe declines in several species of hibernating bats in North America. The model allowed us to estimate initial occupancy, colonization, persistence and prevalence of Pd at bat hibernacula. Additionally, utilizing the relationship between cycle threshold and pathogen load, we estimated pathogen detectability and modeled expected colony and bat pathogen loads. To assess the ability of MS-DOHM to estimate pathogen dynamics, we compared MS-DOHM's results to those of a dynamic occupancy model and naïve detection/non-detection. MS-DOHM's estimates of site-level pathogen presence were up to 11.9% higher than estimates from the dynamic occupancy model and 35.7% higher than naïve occupancy. Including prevalence and load in our modeling framework resulted in estimates of pathogen arrival that were two to three years earlier compared to the dynamic occupancy and naïve detection/non-detection, respectively. Compared to naïve values, MS-DOHM predicted greater pathogen loads on colonies; however, we found no difference between model estimates and naïve values of prevalence. While the model predicted no declines in site-level prevalence, there were instances where pathogen load decreased in colonies that had been Pd positive for longer periods of time. Our findings demonstrate that accounting for pathogen load and prevalence at multiple scales changes our understanding of Pd dynamics, potentially allowing earlier conservation intervention. Additionally, we found that accounting for pathogen load and prevalence within hibernacula and among individuals resulted in a better fitting model with greater predictive ability.

First whole-genome sequence of Triatoma sanguisuga (Le Conte, 1855), vector of Chagas disease

Triatoma sanguisuga is the most widespread triatomine bug species in the United States. The species vectors the human parasite Trypanosoma cruzi, which causes Chagas disease. Vector-borne Chagas disease is rarely diagnosed in the United States, but T. sanguisuga has been implicated in a handful of cases. Despite its public health importance, little is known about the genomics or population genetics of T. sanguisuga. Here, we used long-read sequencing to assemble the first whole-genome sequence for T. sanguisuga using DNA extracted from 1 adult specimen from Delaware. The final size of the genome was 1.162 Gb with 77.7× coverage. The assembly consisted of 183 contigs with an N50 size of 94.97 kb. The Benchmarking Universal Single-Copy Ortholog complete score was 99.1%, suggesting a very complete assembly. Genome-wide GC content was 33.56%, and DNA methylation was 18.84%. The genome consists of 62.75% repetitive DNAs and 17,799 predicted coding genes. The assembled T. sanguisuga genome was very close in size and BUSCO score to that of Triatominae species T. dimidiata (1.16 Gb with 99.1% BUSCO score for T. sanguisuga vs 1.22 Gb with 98.7% BUSCO score for T. dimidiata) and slightly larger than that of T. infestans and Rhodnius prolixus (949 Mb with 90.4% BUSCO score and 706 Mb with 96.5% BUSCO score, respectively). The T. sanguisuga genome is the first North American triatomine species genome to be sequenced, allowing for deeper investigations into epidemiologically relevant aspects of triatomines in temperate climates, thus providing potential vector-borne disease management targets and strengthening public health preparedness.

Differentiating the estrous cycle phases using vaginal vestibule pH and cytology in Asian elephants (Elephas maximus) in human care

Reproductive dysfunction in elephants is often confirmed through blood hormonal assays, as behavioral observations alone are insufficient. While fecal and saliva hormonal analyses offer welfare-friendly alternatives, significant resources are required, limiting practicality in field applications. To improve reproductive management and ensure animal welfare, this study aimed to investigate pH measurements and cytological analysis of the vaginal vestibule to differentiate estrous cycle phases in female elephants, both those with regular and irregular cycling. A total of 106 vaginal vestibule cytological smears from eight regularly cycling females and 39 smears from three irregularly cycling females (confirmed by progesterone and luteinizing hormone [LH] enzyme immunoassays, n = 308 serum samples) were analyzed using staining techniques and pH strip measurements. Based on pH, smears were categorized into acidic, neutral, and alkaline groups. Intermediate cells (ICs) varied significantly across the three groups. In regularly cycling females, ICs dominated during diestrus (67.5 %), whereas estrus was characterized by the absence of ICs and a predominance of superficial cells. ICs decreased in metestrus (36.3 %; P < 0.05). Mean pH levels ranged from acidic in diestrus (5.8) to alkaline in estrus (8.5). In irregularly cycling elephants, pH (6.3) differed from proestrus and estrus in irregularly cycling elephants. Moreover, pH was significantly correlated with progesterone (r = -0.25) and LH (r = 0.4) among all females. Using cytology exclusively was insufficient to differentiate between regular and irregular cyclic statuses; however, when combined with pH measurements, it effectively identified the estrous phases in regularly cycling elephants. This study offers novel findings that could serve as practical, welfare-focused metrics for reproductive assessments in elephants.

Camera traps unable to determine whether plasticine models of caterpillars reliably measure bird predation

Sampling methods that are both scientifically rigorous and ethical are cornerstones of any experimental biological research. Since its introduction 30 years ago, the method of using plasticine prey to quantify predation pressure has become increasingly popular in biology. However, recent studies have questioned the accuracy of the method, suggesting that misinterpretation of predator bite marks and the artificiality of the models may bias the results. Yet, bias per se might not be a methodological issue as soon as its statistical distribution in the samples is even, quantifiable, and thus correctable in quantitative analyses. In this study, we focus on avian predation of lepidopteran larvae models, which is one of the most extensively studied predator-prey interactions across diverse ecosystems worldwide. We compared bird predation on plasticine caterpillar models to that on dead caterpillars of similar size and color, using camera traps to assess actual predation events and to evaluate observer accuracy in identifying predation marks a posteriori. The question of whether plasticine models reliably measure insectivorous bird predation remained unanswered, for two reasons: (1) even the evaluation of experienced observers in the posterior assessment of predation marks on plasticine models was subjective to some extent, and (2) camera traps failed to reflect predation rates as assessed by observers, partly because they could only record evidence of bird presence rather than actual predation events. Camera traps detected more evidence of bird presence than predation clues on plasticine models, suggesting that fake prey may underestimate the foraging activity of avian insectivores. The evaluation of avian predation on real caterpillar corpses was probably also compromised by losses to other predators, likely ants. Given the uncertainties and limitations revealed by this study, and in the current absence of more effective monitoring methods, it remains simpler, more cost-effective, ethical, and reliable to keep using plasticine models to assess avian predation. However, it is important to continue developing improved monitoring technologies to better evaluate and refine these methods in order to advance research in this field.

A comparative developmental study of the avian syrinx: Insights into the homology of the sound-producing muscles in birds

The anatomical innovation of sound-producing organs, which gives rise to a wide variety of sound signals, is one of the most fundamental factors leading to the explosive speciation of modern birds. Despite being a key clue to resolving the homology of sound-controlling muscles among birds, only few studies have explored the embryonic development of syringeal muscles. Using serial histological sections and immunohistochemistry, we described the three-dimensional anatomy and development of the cartilage, muscle, and innervation pattern of the tracheobronchi in three avian species: domestic fowls, cockatiels, and zebra finches. Crucially, the muscle primordia of the syringeal and tracheobronchial muscles develop from the caudal end of the lateral tracheal muscle in cockatiels and zebra finches. Furthermore, the tracheobronchial and syringeal muscle primordia of the zebra finches are subsequently split during embryonic development. Based on our findings on the identity of muscle primordia development and innervation pattern of the hypoglossal nerve between the cockatiels and zebra finches, we suggest that the muscle component traditionally documented as the superficial syringeal muscle in parrots is homologous to the tracheobronchial and ventral syringeal muscles of the zebra finches. These facts not only orchestrate the terminological discrepancies among previous studies, but also suggest that the syringeal muscles were acquired by the anatomical innovation of the lateral tracheal muscles in the common ancestor of the parrots and passerines, and further compartmentalized in the passerines, perhaps leading to a wide song repertoire for acoustic communication.

Functional Morphology of the Tongue and Laryngeal Entrance and Scanning Electron Microscopic Pattern of the Filter Feeding Apparatus of Anas crecca

There is insufficient information about the migratory Eurasian teal, Anas crecca. The study provides the first anatomical description of lingual adaptations and their relationship with the species-specific feeding behavior of A. crecca collected near Egyptian Lake Nasser. Our investigation was applied with the help of gross, scanning electron microscopy (SEM), and morphometric analysis. The study focused on the feeding filtering apparatus that depends on eight lingual papillae. The spatula-shaped nail is adapted for food particle pecking, while the lingual combs, rostral border of the prominence, unique papillary crest, median groove, and papillary system aid in intra-oral transportation. The feeding apparatus is formed by the lateral and dorsal papillary systems. The lateral papillary system had conical papillae with numerous long filiform and hair-like filiform papillae to constitute the food filtration apparatus, while the dorsal papillary system had ridged-like and rod-like papillae in addition to the small papillae of the papillary crest and spinated border of the root to help in moving the food particles with water to the lateral sides of the prominence. The laryngeal region exhibited papillary (pre-glottic) and non-papillary (glottic) areas. The papillary area had two lateral papillary portions and a median smooth portion, while the non-papillary area had an ovoid laryngeal mound with a median glottic opening that was bordered by a papillary border. The papillary portion had three slightly oblique longitudinal papillary rows.

Environmental determinants of West Nile virus vector abundance at the wildlife-livestock interface

The diversity and abundance of vectors are essential parameters in the transmission dynamics of West Nile virus (WNV) between its avian reservoirs and clinically susceptible mammalian species. Knowing the determinants of vector abundance could be thus useful in preventing West Nile fever (WNF) cases and associated socio-economic impact. We designed a survey at the wildlife-livestock interface to test the hypothesis that variations in environmental favourability between anthropized and wild scenarios modulate WNV vector abundance and transmission risk. In a continental Mediterranean region where WNF has recently emerged, we selected nine sampling sites and allocated three areas to every site with a decreasing gradient of wildlife-livestock interaction: A1-a horse farm where interaction is maximal; A2-a zone of intermediate interaction 500-1000 m from the farm; and A3-an entirely wild zone of low interaction 1-5 km from the farm. At a fortnightly frequency, we estimated mosquito abundance at each of the 27 study sites in May-December 2018 and April-July 2019. We estimated bird and mammal abundance, collected meteorological information and characterised mosquito habitat at the site scale. Thereafter, we studied the determinants of Culex spp., Culex pipiens sensu lato (s.l.) Linnaeus, 1758 (Diptera: Culicidae) and Culex theileri  Theobald, 1903 abundance by constructing negative binomial generalised linear mixed models. We identified 20 mosquito species, with a notable predominance of Culex spp. and, particularly, of Cx. pipiens s.l. We found differences in the spatiotemporal distribution of Culex spp. abundance and confirmed our hypothesis by finding important effects of local environmental variations in abundance. The accumulated rainfall in fortnights 4-14 and the mean temperature of the two fortnights before sampling were positively and statistically significantly associated with the abundance of Cx. pipiens s.l. (Z = 13.09, p < 0.001, and Z = 9.91, p < 0. 001, respectively) and Culex spp. (Z = 13.35, p < 0.001, and Z = 6.99, p < 0.001, respectively), while the mean temperature of the two previous fortnights was a positive statistically significant predictor (Z = 14.69, p < 0.001) of the abundance of Cx. theileri. The farm environment was the most conducive predictor to hosting Culex spp. compared with wild settings. Our results indicate that continental Mediterranean environments are favourable for WNV circulation and maintenance, especially the environment of anthropized rural settings such as farms. These results will have an impact on the spatiotemporal risk prediction of WNF emergence in continental Mediterranean environments.

Morphological and histochemical characteristics of the foregut, midgut, and hindgut, and their alterations during ovarian development in female freshwater prawn, Macrobrachium rosenbergii

The anatomical, histological, and histochemical characteristics of the foregut (FG), midgut (MG), and hindgut (HG), as well as their alterations during the ovarian cycle in female prawns, Macrobrachium rosenbergii, were investigated. The esophagus (ESO), cardia (CD), and pylorus (PY) are the main components of the FG. An epithelium (Ep) with thick cuticle (Cu) layers lining the ESO, and the ESO is encircled by the ESO glands. The CD has a thick musculature, whereas the Ep of the PY are characterized by numerous villi and columnar Ep cells with a thinner layer of Cu. The inner longitudinal (LM) and the outer circular (CM) muscles were both present in the PY. The MG is lined by Ep cells which are connected to the basement membrane, and it lacks Cu. Microvilli, and subapical vacuoles are visible on the apical surface of Ep cells of the MG. The outermost layer is characterized by a dense strip of elastic fibers and a cluster of collagen fibers. The HG has the Ep cells with a thin Cu layer, and the HG glands form a rosette-like structure. The HG is surrounded by the CM and the LM fibers. The reactivities of Periodic Acid Schiff and Alcian Blue in these digestive organs altered throughout the ovarian cycle, and this was supported by the increased expression of mucin levels as ovarian maturation progressed. Our results offer novel and significant insights into the anatomical and histochemical structures of these digestive organs, and demonstrate a significant correlation between ovarian development and feeding in the female prawn, M. rosenbergii.

Molecular evolution of dietary shifts in ladybird beetles (Coleoptera: Coccinellidae): from fungivory to carnivory and herbivory

BACKGROUND

Dietary shifts are major evolutionary steps that shape ecological niches and biodiversity. The beetle family Coccinellidae, commonly known as ladybirds, first transitioned from a fungivorous to an insectivorous and subsequently a plant diet. However, the molecular basis of this dietary diversification remained unexplored.

RESULTS

We investigated the molecular evolution of dietary shifts in ladybirds, focusing on the transitions from fungivory to carnivory (Coccinellidae) and from carnivory to herbivory (Epilachnini), by comparing 25 genomes and 62 transcriptomes of beetles. Our analysis shows that chemosensory gene families have undergone significant expansions at both nodes of diet change and were differentially expressed in feeding experiments, suggesting that they may be related to foraging. We found expansions of digestive and detoxifying gene families and losses of chitin-related digestive genes in the herbivorous ladybirds, and absence of most plant cell wall-degrading enzymes in the ladybirds dating from the transition to carnivory, likely indicating the effect of different digestion requirements on the gene repertoire. Immunity effector genes tend to emerge or have specific amino acid sequence compositions in carnivorous ladybirds and are downregulated under suboptimal dietary treatments, suggesting a potential function of these genes related to microbial symbionts in the sternorrhynchan prey.

CONCLUSIONS

Our study provides a comprehensive comparative genomic analysis to address evolution of chemosensory, digestive, detoxifying, and immune genes associated with dietary shifts in ladybirds. Ladybirds can be considered a ubiquitous example of dietary shifts in insects, and thus a promising model system for evolutionary and applied biology.

Exploring different methods of Exaiptasia diaphana infection to follow Vibrio parahaemolyticus dissemination in the whole animal

An increase in wastewater rejection and rising seawater temperature are the two main causes of the spreading of pathogenic bacteria in the ocean that present a risk to the health of marine organisms, i.e., corals. Deciphering the infectious mechanism is of interest to better disease management. The quantity of infecting bacteria as well as method of pathogen administration is an important parameter in studying host-pathogen interactions. In this study, we have tested two models of infection (bathing or injection) of Exaiptasia diaphana (E. diaphana) with a clinically isolated strain of Vibrio parahaemolyticus expressing constitutively a Green Fluorescent Protein (Vp-GFP). We followed Vp-GFP dissemination over time with confocal microscopy at 6, 24, and 30 h. During the early time of infection, bacteria were observed adhering to the ectoderm in both infection methods. In later stages of the infection, Vp-GFP were lost from the ectoderm and appeared in the gastroderm. Compared to bathing, the injection method was supposed to provide better control of the bacteria quantity introduced inside the animal. However, injection induced a stress response with contraction and rejection of bacteria thus making it impossible to control the number of infecting bacteria. In conclusion, we recommended using the bathing technique that is closer to the infection route found in the environment and, moreover, did not cause injury to the animal. We also demonstrated, by using Vp-GFP, that we could track pathogenic bacteria in different tissues of E. diaphana over the time of infection and quantify them in the whole animal, thus opening a technical approach for developing new strategies to fight infection disease.

Plastic sex-trait modulation by differential gene expression according to social environment in male red deer

Mate competition encourages individuals to modulate characters involved in mating success. Adult Iberian red deer (Cervus elaphus hispanicus) males show a dark ventral patch (DVP) that plays a central role in mating rivalry, whose size and chemical compounds varied according to the level of male-male competition within the population. In the pigmentation of the DVP appears, after urinary excretion, a molecule called DOPEG originating from the metabolism of norepinephrine, leading us to investigate whether differential expression mechanisms of key genes dopamine B-hydroxylase (DBH) and tyrosine hydroxylase (TH), encoding enzymes catalyzing the process can be sensitive to different competitive population situations and responsible for the plastic development of the DVP in red deer. We found that social environment with higher intrasexual competition, where male invest more in sexual traits, was associated with increased levels of DBH and TH transcripts, while Dopamine showed reversed values. We found alternative splicing for the TH gene, although differences between social environments appeared just related to expression levels. Our results support the internal cause of trait modulation based on differential gene expression in relation to the conditions of intrasexual competition in social environment. We propose the quantification of DBH transcripts as a molecular biomarker of male red deer reproductive activity.

Alleviating isolation stress in chickens: The benefits of home pen playback and mirrors

This study investigated whether the provision of (1) a mirror or (2) video and sound playback of conspecifics in the home pen (i.e., playback) could alleviate stress in socially isolated adult domestic chickens. Thirty adult chickens participated in the study, undergoing three-minute sessions of social isolation over three consecutive days in an arena containing a tray of food treats. Each chicken was exposed to three conditions, one per day, in a semi-randomised order: (1) mirror, (2) playback, and (3) control. Video recordings of the tests were coded for stress-related behaviours, including stress behaviour (i.e., pooled stress vocalisations and escape behaviour), vigilance, feeding, and exploration. Additionally, thermal imaging was used to measure the surface temperatures of the eye and comb. Social isolation elicited mild stress responses, as evidenced by reduced surface eye and comb temperatures along with the exhibition of stress and vigilance behaviours. Both playback and mirror conditions appeared to reduce stress behaviours compared to the control, although the effect of the mirror was not statistically significant. It is possible that the playbacks simulated the presence of a group of calm conspecifics. Vigilance behaviour, however, remained unaffected across conditions. These findings suggest that playback, and to a lesser extent mirrors, may alleviate certain stress-related behaviours in socially isolated adult chickens. As individual variation was high, future research should explore the role of individual differences in stress responses, as well as the long-term effects of repeated exposure to mirrors and playback, along with other environmental variables.

Reproductive Potential and Population Growth of the Worm Enchytraeus buchholzi (Clitellata: Enchytraeidae) Under Laboratory Conditions as Well as Regression Models

The worm Enchytraeus buchholzi is a new pest injuring American ginseng Panax quinquefolium. To explore its reproductive potential and then estimate its population dynamics, the authors conducted two related experiments: (1) measuring individual fecundity in its lifetime by rearing each of the parent adults alone in a wet sandy dish at 18 and 21 °C indoors; (2) testing population growth by rearing each of the parent adults together with its offspring for a time longer than two generations at 21 °C. In Experiment I, five dependent variables, namely daily mean cocoons (DMC), cumulative cocoons (CC), eggs per cocoon (EPC), daily mean eggs (DME) and cumulative eggs (CE), were extracted, with each of them subject to a stepwise regression analysis on rearing time (T) and its power series as independent variables. Equaling to the net reproductive rate (R0), the generational adult equivalent (GAE) was calculated via a conversion of F1 generational eggs into adult equivalents (AE). In Experiment II, both an exponential and a logistic function were applied to construct regression equations. The results indicated that (1) a parent adult of E. buchholzi was able to live for a period as long as 10 and 13 full generations at the two temperatures tested and lay 84.8 and 110.6 cocoons containing 545 and 714 eggs, respectively; (2) DMC reached its maximum between 7 and 9 days of rearing and then declined slowly along a straight regression line; (3) CC rose steadily along a quadratic curve; (4) both EPC and DME varied following a cubic curve; (5) CE increased steadily along a cubic curve; (6) the new polynomial models suitably reflected the numerical growth trends of cocoons and eggs in the F1 generation in a broad sense, while corresponding derivative equations quantified both the daily reproductive potential and resistance of the worm, thus revealed its daily reproductive capacity; (7) R0 was 41.2 AE at 21 °C and 42.5 AE at 18 °C when a population of E. buchholzi lived in a niche with unlimited ambient resources; (8) this kind of temporal population generated by individual reproduction had fully demonstrated its significant, generational reproductive potential; and (9), through living in such a limited area as the wet sandy dish, bypassing an exponential growth process, the laboratory population grew up along a logistic curve from the F1 to F3 generations. The statistical relationships help to comprehend the individual reproduction of E. buchholzi, understand deeply the logical sequence and the difference between individual and population reproductions, predict population dynamics of the worm, and provide its integrated pest management with a solid basis. The experimental study has expanded theories on bionomics and population ecology, opening up a new area for research work in related fields.

Climate-related drivers of migratory bird health in the south-central USA

Migratory birds are species of concern that play important ecological roles while also supporting recreational opportunities for the hunting and birdwatching public. Direct and indirect effects of climate variability, extremes, and change on migratory bird health manifest at the individual, population, species, and community levels. This review focuses on the effects of climate on migratory birds that spend part of their life cycles in the south-central USA. Although gaps in knowledge remain, prior studies provide a solid foundation to understand how climate affects migratory birds to inform management priorities and actions.

Antipredator behaviour in semi-feral horses: innate response and the influence of external factors

Rewilding can play a vital role in safeguarding biodiversity, with the grazing pressure exerted by large ungulates and controlled by their predators being a significant factor, particularly in European contexts. Domestic horses are becoming integral to such ungulates' biomass, but they may differ from truly wild species due to their domesticated origin. This raises concerns about whether feral horses retain adequate antipredator behaviours, especially in the presence of expanding, large predators like wolves. The field of antipredator behaviour research is hampered by inconsistent results and a lack of standardisation, and the behaviour of free-ranging horses remains underexplored. To address this gap, we conducted a playback experiment on semi-feral Exmoor ponies (n = 97) in the Czech Republic, exposing them to wolf howls, deer rut calls, and static noise as a control. We assessed alert behaviour and herd grouping while accounting for variables such as herd size, sex, time of day, weather conditions, environment type, presence of other ungulates, and habituation effects. Over 70% of the ponies exhibited alert behaviour in response to both wolf and deer calls. Although the magnitude of responses did not differ significantly between wolf and deer calls, both elicited distinct reactions compared to the control. Most of the studied external factors significantly affected the observed alert responses, highlighting that they must be carefully considered in such studies since these may explain the conflicting results observed in previous studies. The significant behavioural differences in reaction to the sounds indicate that the horses can differentiate them and likely still possess some innate memory, as reported in other ungulates. This is a positive sign towards reintroduction. Future research should carefully consider the validity of the testing environment, habituation effects, and other external factors to ensure robust results.

On Cytheridellawhitmani sp. nov. (Crustacea, Ostracoda) from Cape Cod (Massachusetts, USA), with a reappraisal of the taxonomy of the genus

Cytheridellawhitmani Martens, sp. nov. is described from lakes on Cape Cod (MA, USA). The species differs from its congeners mainly by the shape of the female carapace and by the morphology of the hemipenis, especially of the distal lobe and the copulatory process. The literature on the genus is reviewed and the synonymy of the fossil Cytheridellaboldii Purper, 1974 with the type species C.ilosvayi Daday, 1905, both described from South America, is confirmed. The status of Cytheridellaamericana (Furtos, 1936) is reverted to that of "uncertain species". Beside the type species and the new species, the genus currently includes only three further species from Africa: C.monodi Klie, 1936, C.damasi Klie, 1944 (with synonym C.chariessa Rome, 1977), and C.tepida Victor, 1987. The morphology of the new species is discussed in comparison with the congeneric species, especially regarding the valve ornamentation, the structure and function of the third thoracopod, the hemipenis and the caudal ramus. It is suggested that C.whitmani is a recent invasive species in the lakes of the Cape Cod peninsula. Its occurrence at northern latitudes is unexpected, as its congeneric species are consistently (sub-) tropical.

Unveiling hidden diversity: Phylogenomics of neotomine rodents and taxonomic implications for the genus Peromyscus

Neotomine rodents (Cricetidae, Neotominae) represent one of the most commonly encountered and diverse group of rodents in North America, yet phylogenetic relationships within this group remain uncertain. This subfamily is known for its rapid evolution, adding more complexity to our efforts to unravel their evolutionary history. The main debate revolves around the recognition of the genus Peromyscus as monophyletic or paraphyletic due to its relationship with other genera such as Habromys, Megadontomys, Podomys, Neotomodon, and Osgoodomys. Here, we aim to resolve phylogenetic relationships within Neotominae, to further explore their evolutionary history and taxonomic boundaries. We used target capture and high-throughput sequencing of complete mitogenomes and thousands of genome-wide ultraconserved elements loci (UCEs). Our comprehensive analyses encompassed 53 species of Neotominae spanning 12 previously described genera, along with one yet-undescribed genus. We also investigated 12 out of the 13 species groups within Peromyscus. Our analyses, including Maximum Likelihood and Bayesian Inference with both mitogemomes and UCEs, as well as the coalescent species-tree-based approach with UCEs, consistently recovered concordant and well-resolved phylogenies with high levels of nodal support. We identified seven main clades within Neotominae that could potentially be recognized at the generic level, mostly to categorize the genus Peromyscus as a monophyletic group, including one species group within "Peromyscus". Furthermore, our divergence dating estimates place the crown age of Neotominae to be around the late Miocene at ca. 7.9 - 10.7 mya. While generic level diversification continued through the Pliocene, species level diversification predominantly occurred during the late Pliocene, extending through the Pleistocene and Holocene. These epochs have been recognized as periods with significant changes in flora and fauna, driving ecological transformations on a global scale. We hypothesized that climatic and vegetation shifts during the Neogene and Quaternary, coupled with geological events, topographical features, and the presence of biogeographical corridors played a pivotal role in the speciation and diversification of Neotominae. Recognizing the importance of generating genomic-scale data coupled with a broad taxonomic sampling, our study, for the first time, offers resolution of the relationships among the main lineages of Neotominae. We expect that the phylogeny presented here will serve as a foundational resource for future systematic and evolutionary studies. This includes facilitating a proper comprehensive taxonomic revision of the group and the formal description and naming of new genera.

Validating a Mixed Qualitative Behavioral Assessment for Adult Western Lowland Gorillas (Gorilla gorilla gorilla) I: Baseline Monitoring

Traditional qualitative behavioral assessments (QBAs) employ a unique whole-animal approach to measure animal welfare with a focus on affective elements. QBAs require comprehensive validation including reliability across multiple raters, subjects, and institutions, as well as consistency with other validated assessment measures. In 2016, the Detroit Zoological Society developed and began internally validating the Gorilla Behavioral Assessment Tool (GBAT), followed by internal applications of a revised GBAT in 2021. This study continues these validation efforts through the multi-institutional application of the GBAT in baseline conditions. Five zoological institutions participated in this study, creating a study population of 15 adult male western lowland gorillas (Gorilla gorilla gorilla) and more than 40 staff. Care staff collected fecal samples from each gorilla, and two staff from each institution completed the GBAT for each gorilla daily. Three of the five institutions collected focal behavioral data. We calculated inter-rater reliability using Gwet's AC2, establishing near-perfect reliability across all tested items. We found no significant variation in reliability between institutions. We used the behavioral data and fecal glucocorticoid metabolites for construct validation. A combination of Spearman's correlations and generalized linear mixed models demonstrated statistically significant relationships between seven of the 12 tested GBAT items and other established measures. Integration of physical and behavioral indicators of welfare alongside affective indicators alters the GBAT from a traditional QBA into what we propose as a mixed or M-QBA. Our work demonstrates how an M-QBA allows for a more comprehensive assessment of animal welfare with implications for broader research applications.

Toxic effects of exposure to polymethyl methacrylate and polyvinyl chloride microplastics in Pacific oysters (Crassostrea gigas)

Increasing attention has been directed toward the toxic effects of microplastics (MP) on marine mollusks in recent years. To evaluate these effects, Pacific oysters (Crassostrea gigas) were acclimated and cultured in a 140-Liter container, where two types of MP, polymethyl methacrylate (PMMA) and polyvinyl chloride (PVC), were introduced into their feed. MP concentrations in the water were maintained at 300 μg/L, 600 μg/L, and 900 μg/L to assess oxidative stress, DNA damage, and metabolic disorders in these organisms. Significant alterations in antioxidant enzyme activities were detected in C. gigas exposed to these pollutants. After 30 days of exposure to high concentrations of PMMA, superoxide dismutase (SOD) activity in the adductor muscle was reduced by 59% compared to the control group, while catalase (CAT) activity increased by 67%. DNA damage assessments revealed that NF-κB expression levels reached a maximum value of 2.46 in the high-concentration PMMA group after 30 days, the highest among all experimental groups. Additionally, metabolic pathway alterations in the hepatopancreas of C. gigas were observed, including reduced expression levels of uridine and methylmalonic acid (MMA), alongside significantly elevated expression levels of glutamic acid and asparagine. This study offers essential toxicological data for understanding and quantifying the impacts of PMMA and PVC MP on marine mollusks.

BDH1 identified by transcriptome has a negative effect on lipid metabolism in mammary epithelial cells of dairy goats

BACKGROUND

The 3-hydroxybutyrate dehydrogenase 1 (BDH1) mainly participates in the regulation of milk fat synthesis and ketone body synthesis in mammary epithelial cells. In our previous study, BDH1 was identified as a key candidate gene regulating lipid metabolism in mammary glands of dairy goats by RNA-seq. This study aimed to investigate the effect of BDH1 on lipid metabolism in mammary epithelial cells of dairy goats (GMECs).

RESULTS

The results suggest that BDH1 plays a significant role in reducing triacylglycerol content and lipid droplet accumulation in GMECs (p < 0.05). Overexpression of BDH1 significantly decreased the expression of lipid metabolism-related genes (SREBF1 and GPAM) and reduced the levels of C14:0 and C17:1, while increasing FABP3 expression and C10:0 concentration (p < 0.05). Interference with BDH1 significantly increased the expression of SREBF1 and GPAM and the concentration of C14:0, C15:1, and C20:1, but significantly decreased FABP3 and C18:0 (p < 0.05). Treatment of GMECs with β-hydroxybutyric acid (R-BHBA) significantly decreased the expression of FASN, ACACA, LPL, SREBF1, FABP3, ACSL1, GPAM, DGAT1, and triacylglycerol content, while significantly increasing the expression of BDH1 (p < 0.05). Interference with BDH1 rescued the reduction of cellular TAG content and the expression of FASN, LPL, SREBF1, ACSL1, and GPAM in BHBA-treated GMECs.

CONCLUSION

In conclusion, BDH1 negatively regulates lipid metabolism in mammary glands of dairy goats. Furthermore, it may mitigate the inhibitory effect of R-BHBA on lipid metabolism in GMECs.

Impact of mild hypothermic circulatory arrest on surgical outcomes in acute type a aortic dissection patients: a single-centre study

BACKGROUND

As hypothermic circulatory arrest (HCA) is being more frequently induced in patients undergoing aortic arch surgery, its safety at different degrees has become a crucial area of study. The aim of this study was to assess the surgical outcomes of mild hypothermic circulatory arrest (MI-HCA) during aortic arch surgery.

METHODS

Acute type A aortic dissection (ATAAD) patients who underwent total arch replacement (TAR) and frozen elephant trunk (FET) surgery between January 2014 and December 2023 were enrolled in this study. The patients were divided into two groups according to the minimum nasopharyngeal temperature: the moderate hypothermic circulatory arrest (MHCA) group (20-28 °C) and the MI-HCA group (> 28 °C). The inverse probability of treatment weighting (IPTW) was used to balance differences in the baseline characteristics. Perioperative variables were analysed via pairwise comparisons, multivariable logistic regression, and subgroup forest plots to assess the impact of MI-HCA on surgical outcomes.

RESULTS

A total of 447 patients were included in this study, and the mean minimum nasopharyngeal temperature was 24.80 (23.98, 27.30) °C in the MHCA group and 30.10 (29.80, 30.70) °C in the MI-HCA group. The incidence of acute kidney injury (AKI) in the MI-HCA group was lower than that in the MHCA group (52% vs. 78%, p < 0.01). In the multivariable logistic regression analysis, MI-HCA was identified as an independent protective factor for AKI (OR = 0.354, 95% CI 0.177-0.689; p = 0.003). Additionally, compared with MHCA, MI-HCA was not associated with an increased incidence of stroke, spinal cord injury, or in-hospital mortality. After IPTW, the preoperative and intraoperative data of the patients were balanced, and the incidence of AKI in the MI-HCA group was still lower than that in the MHCA group (83.26% vs. 53.61%, p = 0.004). The subgroup forest plot also demonstrated that MI-HCA was a protective factor for postoperative AKI.

CONCLUSIONS

The surgical outcomes of MI-HCA in ATAAD patients were satisfactory. Compared with MHCA, MI-HCA provided sufficient protection for distal organs, the brain, and the spinal cord, with a significantly lower incidence of AKI. These results indicate that MI-HCA could be a better approach for ATAAD surgery.

Transcriptional Pathways Predisposing to Cancer Oxidative Stress Sensitivity and Resistance Are Shared Between Hydrogen Peroxide and Cold Gas Plasma but Not Hypochlorous Acid

Oxidative stress is universal to all cell types, including cancer. It is elicited by a surplus of reactive oxygen species (ROS) or a reduced cellular ability to defend against those. At low levels (oxidative eustress), this induces altered cellular signaling, while at higher levels (oxidative distress), cellular toxicity and non-specific redox signaling become apparent. While oxidation-induced cell death is a hallmark of many cancer therapies, including ROS-producing radiotherapy, some chemotherapies and targeted therapies, photodynamic therapy, and recently emerging physical modalities such as medical gas plasma (a multi-ROS generating technology), less is known about the transcriptional profiles predisposing cancer cells to oxidative demise. In particular, which genes are associated with resistance or sensitivity to ROS overload and subsequent toxicity has not been systematically investigated. Moreover, it is unclear if there are differences between oxidant types, such as hydrogen peroxide and hypochlorous acid. To this end, we here employed 35 cell lines of various origins (e.g., adenocarcinoma, melanoma, leukemia, squamous cell carcinoma, and neuroblastoma). We first performed in-house transcriptomic analysis to assess baseline transcriptional profiles. Second, all cell lines were exposed to four different ROS concentrations of either hydrogen peroxide, hypochlorous, or gas plasma exposure. Third, correlation analysis was performed to identify genes associated with (i) oxidative stress sensitivity, (ii) oxidative stress resistance, and (iii) similarities and/or differences between the different oxidative stress inducers. Intriguingly, distinct gene sets were found for all treatments, and there was a striking difference between hydrogen peroxide and hypochlorous acid, suggesting different modes of action of both oxidants.

Insights Into the Reproduction and Maturity of the Spinetail Devil Ray (Mobula mobular)

Little is known about the reproductive biology of the endangered spinetail devil ray (Mobula mobular). Here, we describe the reproductive behavior, estimates of age, size at maturity, embryonic development in the uterine cavity, and the morphology of a neonate produced by a male and female ray kept in Osaka Aquarium KAIYUKAN for 7.5 years. The reproductive behaviors observed included initiation, endurance, evasion, pre-copulation positioning, copulation, and separation. The disc widths (DW) of male and female rays displaying reproductive behaviors were 203 and 204 cm, respectively. The male was estimated to be 7.7 years old after elongation of claspers, while the female was estimated to be 8.9 years old at first mating. A neonate was born 464 days after successful copulation, weighing 11.32 kg, with a DW of 104 cm. These observations are consistent with those of previous studies conducted on wild individuals. This is one of the few reports on the reproductive behavior of spinetail devil ray. Research conducted on this species in captivity is expected to help fill the knowledge gaps for this poorly studied species.

Proteomics of the Dark-Ventral-Patch Sexual Signal in Male Red Deer

Sexual signals in animals encompass a variety of forms including visual, acoustic, and chemical signals that are fundamental for intra- and interspecific communication, including sexual selection processes. Among these, odor signals play a critical role. Chemical compounds involved in sexual signaling vary in nature, with lipids and proteins being particularly important. In the male Iberian red deer (Cervus elaphus hispanicus), the dark ventral patch has been identified as a key sexual signal during mating competition, associated with specific chemical compounds deposited during urination. Hair plays a significant role in this signaling due to its ability to retain compounds on the scales of the hair cuticle. In this study, we used a shotgun proteomic approach to investigate whether the ventral patch hair retains proteins on its surface that could reveal metabolic and cell-signaling adaptations potentially related to reproductive activity. Characterization of the origin and functionality of the proteins found in the hair of the dark ventral patch of male red deer, and their relationship to distinct metabolic pathways, provides an initial understanding of the potential role of these compounds in chemical communication in red deer intrasexual competition for mates.

Identification of the Highly Polymorphic Prion Protein Gene (PRNP) in Frogs (Rana dybowskii)

Prion diseases are fatal neurodegenerative diseases that can be transmitted by infectious protein particles, PrPScs, encoded by the endogenous prion protein gene (PRNP). The origin of prion seeds is unclear, especially in non-human hosts, and this identification is pivotal to preventing the spread of prion diseases from host animals. Recently, an abnormally high amyloid propensity in prion proteins (PrPs) was found in a frog, of which the genetic variations in the PRNP gene have not been investigated. In this study, genetic polymorphisms in the PRNP gene were investigated in 194 Dybowski's frogs using polymerase chain reaction (PCR) and amplicon sequencing. We carried out in silico analyses to predict functional alterations according to non-synonymous single nucleotide polymorphisms (SNPs) using PolyPhen-2, PANTHER, SIFT, and MutPred2. We used ClustalW2 and MEGA X to compare frog PRNP and PrP sequences with those of prion-related animals. To evaluate the impact of the SNPs on protein aggregation propensity and 3D structure, we utilized AMYCO and ColabFold. We identified 34 novel genetic polymorphisms including 6 non-synonymous SNPs in the frog PRNP gene. The hydrogen bond length varied at codons 143 and 207 according to non-synonymous SNPs, even if the electrostatic potential was not changed. In silico analysis predicted S143N to increase the aggregation propensity, and W6L, C8Y, R211W, and L241F had damaging effects on frog PrPs. The PRNP and PrP sequences of frogs showed low homology with those of prion-related mammals. To the best of our knowledge, this study was the first to discover genetic polymorphisms in the PRNP gene in amphibians.

Bellymount-pulsed tracking: a novel approach for real-time in vivo imaging of Drosophila abdominal tissues

Quantitative live imaging is a valuable tool that offers insights into cellular dynamics. However, many fundamental biological processes are incompatible with current live-imaging modalities. Drosophila oogenesis is a well-studied system that has provided molecular insights into a range of cellular and developmental processes. The length of the oogenesis, coupled with the requirement for inputs from multiple tissues, has made long-term culture challenging. Here, we have developed Bellymount-pulsed tracking (Bellymount-PT), which allows continuous, noninvasive live imaging of Drosophila oogenesis inside the female abdomen for up to 16 h. Bellymount-PT improves upon the existing Bellymount technique by adding pulsed anesthesia with periods of feeding that support the long-term survival of flies during imaging. Using Bellymount-PT, we measure key events of oogenesis, including egg chamber growth, yolk uptake, and transfer of specific proteins to the oocyte during nurse cell dumping with high spatiotemporal precision within the abdomen of a live female.

Understanding Genetic Regulation of Sex Differentiation in Hermaphroditic Fish

As a fundamental taxonomic group within vertebrates, fish represent an invaluable resource for investigating the mechanisms underlying sex determination and differentiation owing to their extensive geographical distribution and rich biodiversity. Within this biological cohort, the processes of sex determination and differentiation are intricately governed by both genetic factors and the complex interplay of environmental cues. While variations in external environmental factors, particularly temperature, can exert a modulatory influence on sex differentiation in fish to a limited degree, genetic factors remain the primary determinants of sexual traits. Hermaphroditic fish display three distinct types of sexual transitions: protandry (male to female), protogyny (female-to-male), bidirectional sex change (both directions serially). These fish, characterized by their unique reproductive strategies and sexual plasticity, serve as exemplary natural models for elucidating the mechanisms of sex differentiation and sexual transitions in fish. The present review delves into the histological dynamics during gonadal development across three types of sequential hermaphroditic fish, meticulously delineating the pivotal characteristics at each stage, from the inception of primordial gonads to sexual specialization. Furthermore, it examines the regulatory genes and associated signaling pathways that orchestrate sex determination and differentiation. By systematically synthesizing these research advancements, this paper endeavors to offer a comprehensive and profound insight into the intricate mechanisms governing sex differentiation in sequential hermaphroditic fish.

Sticky organisms create underwater biological adhesives driven by interactions between EGF- and GlcNAc- containing polysaccharides

Marine and terrestrial organisms often utilise EGF/EGF-like domains in wet adhesives, yet their roles in adhesion remain unclear. Here, we investigate the Barbatia virescense byssal system and uncover an oxidation-independent, reversible, and robust adhesion mechanism where EGF/EGF-like domain tandem repetitions in adhesive proteins bind robustly to GlcNAc-based biopolymer. EGF/EGF-like-domain-containing proteins demonstrate over three-fold superior underwater adhesion to chitosan compared to the well-known strongest wet-adhesive proteins, mefp-5, and suckerin, when adhering to mica in an surface forces apparatus-based measurement. Additionally, as the degree of acetylation of chitosan decreases from 20.0 to 5.34%, the underwater adhesion energy between mefp-2 and chitosan decreases from |Wad | ≈ 41.80 to 12.92 ± 0.40 mJm-2. This finding highlights the importance of GlcNAc over GlcN in binding with EGF to formulate effective underwater adhesives, expanding our understanding of underwater adhesion and supporting EGF's functional role in biomedical wet adhesive interfaces, hydrogels, and chitosan applications.

Cellular pathway disturbances elicited by realistic dexamethasone concentrations in gills of mussel Mytilus galloprovincialis as assessed by a multi-biomarker approach

The growing usage of glucocorticoids for a variety of diseases raises concerns since these drugs, including the anti-inflammatory dexamethasone (DEX), are frequently found in the environment. The impact of DEX was evaluated on mussels Mytilus galloprovincialis (Lamarck, 1819) by exposure to environmental concentrations (C1: 4 ng/L; C2: 40 ng/L; C3: 400 ng/L; C4: 2000 ng/L), and sampling at 3 (T3), 6 (T6), and 12 (T12) days. A multi-biomarker approach was applied on gills, involved in gas exchange, feed filtering, and osmoregulation. A dose- and time-dependent uptake of DEX was recorded, besides haemocyte infiltration, increased neutral and acid mucopolysaccharides, and a general pro-oxidant effect witnessed by lipid peroxidation and altered antioxidant system. Metabolomics revealed rise in protein turnover and energy demand by fluctuations in free amino acids (alanine, glycine) and energy-related metabolites (succinate, ATP/ADP). It is necessary to reduce DEX dosage from the environment by recovery strategies and effective eco-pharmacovigilance programs.

Simultaneous exposure to microplastics and heavy metal lead induces oxidative stress, histopathological damage, and immune dysfunction in marine mussel Mytilus coruscus

The increasing deposition of microplastics (MPs) in aquatic ecosystems is a worldwide concern. MPs can interact with other environmental pollutants, such as heavy metals, and change their toxicity. In this study, we focused on the effects of MPs and lead (Pb), as a toxic heavy metal, on marine mussel Mytilus coruscus under separate and co-exposure situations at environmentally relevant concentrations: MPs (1 mg/L) and Pb (50 μg/L). We found that MPs alone or in combination with Pb significantly decreased the respiration and filtration rates of the mussels (p < 0.05). Histological observations revealed varying extents of damage to the gill and digestive gland caused by a single exposure to MPs, which was aggravated by co-exposure to Pb. In addition, co-exposure induced a higher level of oxidative stress, which was reflected by an increase in hydrogen peroxide and malondialdehyde content, and a decrease in antioxidant enzyme activity. Meanwhile, co-exposure poses a significant threat to the immune function of the mussels, as evidenced by induction of hemocytes to produce excess reactive oxygen species (ROS), significantly reducing lysosome activity (p < 0.05), inhibiting the expression of autophagy-related genes, and inducing the expression of apoptosis-related genes, resulting in hemocyte apoptosis. Furthermore, the TLR/MyD88/NFκB signaling pathway is involved in the immune response of mussels to environmental stress. This study provides novel perspectives on the toxicity of MPs combined with Pb in marine animals, as well as the molecular mechanisms underlying their ecotoxicological effects.

Cultured Chinese Giant Salamander Skin and Skin Secretions as a Source of Bioactive Peptides for Food and Medicine

Amphibians are enjoyable globally for their culinary value and are increasingly considered alternative protein sources. However, the skin of edible amphibians, especially giant salamanders, is often discarded without much thought. However, this underutilized resource holds significant potential for yielding valuable proteins and bioactive peptides (BPs). These peptides, such as brevinins, bombesins, dermaseptins, esculentins, magainins, temporins, tigerinins, and salamandrins, possess a wide range of biological activities, including antioxidant, antimicrobial, anticancer, and antidiabetic properties. This review provides a comprehensive analysis of the various BPs derived from giant salamander skin or secretions and their associated biological functions. Furthermore, it examines the nutritional composition of giant salamanders, their production status, and the challenges surrounding the use of their skin and secretions. This review also explores the potential applications of these BPs in the food and biomedical industries, particularly as multifunctional food additives, dietary supplements, and drug delivery agents.

Different life strategies of closely related louse species in sympatry: specialist and "generalist" lineages of Polyplax serrata

The origin and significance of host specificity are intriguing questions in parasitology. In the case of single-host versus multiple-host parasites, this topic integrates with the concept of the specialist/generalist trade-off. We use the model of sucking lice Polyplax serrata and rodent hosts Apodemus, to address these concepts. Polyplax serrata was shown to form a complex genetic structure, with a strictly specific S lineage living on Apodemus flavicollis, and a less specific N lineage on A. flavicollis and Apodemus sylvaticus. Moreover, the S lineage formed two mitochondrial clades with geographically exclusive distributions and a narrow hybrid zone, providing an opportunity to test the hypothesis that hybrids suffer a decrease in fitness. We sampled 451 individual lice from two host species at 103 localities. We used prevalences and intensities as proxies of fitness, which the parasites realize on their host. The S lineage, strictly specific to Apodemus flavicollis, reached significantly higher prevalences and intensities on its host compared with the N lineage. Conversely, the N lineage occurred with high prevalence and intensity on A. sylvaticus but tended to use also A. flavicollis when the louse populations became too dense. We discuss possible mechanisms behind this difference (particularly interspecific competition as a typical phenomenon in the specialist/generalist systems). We conclude that a parasite's "choice", not accessibility of the host or interspecific competition, is the main factor affecting the louse prevalences. We suggest that historical differences in geographic distribution of both lice and mice may provide a possible explanation for the observed life strategy differences. In contrast to the convincing picture in S and N lineage prevalences, we did not detect an expected drop in fitness in hybrids. We consider instability of the hybrid zone, or decline in abundance of the respective hosts, as possible explanations for this result.

Key Concepts for Enhancing Zoo Animal Welfare: Coping, Comfort, Choice, Control, Challenge, and Compassion

Zoo animal welfare is subject to increasing scrutiny by many audiences. Although zoo husbandry and management techniques have progressed, common welfare issues are still apparent. To encourage further improvements, converting theoretical welfare definition into practical application is key. This paper evaluates a familiar definition to form a baseline for practical welfare assessment that benefits animals and zoo operations. If we consider coping and comfort as measurable indicators, plus choice and control to cement autonomy for the animal, achieving positive welfare is more likely. Providing positive cognitive challenge results in improvements to behavioral diversity. When husbandry is ecologically relevant, this welfare-friendly approach evolves into husbandry-based evidence, further justifying approaches to animal care. The human element of husbandry (e.g., development and training of personnel) impacts on welfare, necessitating a compassionate approach to daily operations. Compassion - for animal and human wellbeing - ultimately embeds welfare as a core zoo goal. The unique environment of the zoo, with its mix of wild species, human workforce and visitors, coupled with the amount we still must learn about species' husbandry needs emphasizes continual development of welfare approaches.

Koala MHCII association with chlamydia infertility remains equivocal: a need for new research approaches

Chlamydiosis is a common infectious disease impacting koalas and is a major cause of population decline due to resulting mortality and infertility. Polymorphisms of major histocompatibility complex (MHC) genes influence chlamydial disease outcomes in several species but koala studies have produced variable results. We aimed to identify the MHC II DAB and DBB repertoire of koalas from Liverpool Plains, NSW, a population heavily impacted by chlamydiosis. We compared variants between two studies, age cohorts and chlamydial infertility groups. Four DBB and eight DAB alleles were identified. The mean number of DAB alleles per individual increased and allele frequencies differed relative to a previous study, however the mean number of DBB alleles per individual decreased generationally, between age cohorts. DAB allele frequencies differed among fertility groups but contributing alleles could not be identified. While there is a likely role of MHCII in the complex pathogenesis of chlamydiosis, this study suggests that single gene association studies are not appropriate for understanding the impact of host genetics on koala chlamydiosis. A shift to larger multivariate studies is required to yield functional information on complex immunological interactions, and to inform targeted koala conservation across its diverse range and host-pathogen-environment contexts.

Individual identity of alarm calls in wild-living Brandt's voles (Lasiopodomys brandtii)

We investigated acoustic variation responsible for the individuality of alarm calls produced by 50 Brandt's voles Lasiopodomys brandtii derived from 50 different wild-living colonies. For the first time, we described the calling pattern of Brandt's voles, producing a long series of short alarm calls with short inter-call intervals. The alarm calls displayed four different contours of fundamental frequency but were nevertheless strongly individually distinct within a series of 50 successive alarm calls per caller (2500 analyzed alarm calls). The average value of correct assignment of alarm calls to individuals with discriminant function analysis was 15 times higher than the value expected by chance and was robust, not decreasing with cross-validation. We discuss that the highly individualistic alarm calls provide a basis for individual recognition of callers by colony members. At the same time, heterogeneity of call contours makes the long call series less monotonous, potentially preventing habituation and promoting alertness of conspecific call recipients.

A Systematic Review of the Distribution and Prevalence of Viruses Detected in the Peromyscus maniculatus Species Complex (Rodentia: Cricetidae)

The North American Deermouse, Peromyscus maniculatus, is one of the most widespread and abundant mammals on the continent. It is of public health interest as a known host of several viruses that are transmissible to humans and can cause illness, including the acute respiratory disease Hantavirus pulmonary syndrome (HPS). However, recent taxonomic studies indicate that P. maniculatus is a complex of multiple species, raising questions about how to identify and interpret three decades of hantavirus monitoring data. We conducted a systematic review investigating the prevalence and spatial distribution of viral taxa detected in wild populations allocated to P. maniculatus. From the 49 relevant studies published from 2000 to 2022, we extracted and analyzed spatial occurrence data to calculate weighted populational prevalences for hantaviruses. We found that detection efforts have been concentrated in the Western United States and Mexico with a focus on the spread of Sin Nombre virus (Orthohantavirus sinnombreense), the primary causative agent of HPS. There are significant gaps in the existing literature both geographically and in regard to the types of viruses being sampled. These results are significantly impacted by a recent taxonomic split of P. maniculatus into four species, and we were able to update 94% of hantavirus observations to reflect this change. Investigating the uncertain, and likely multiple, phylogenetic histories of these viral hosts should be a key emphasis of future modeling efforts.

A Comparison of the Mitochondrial Performance between Migratory and Sedentary Mimid Thrushes

Birds exhibit a variety of migration strategies. Because sustained flapping flight requires the production of elevated levels of energy compared to typical daily activities, migratory birds are well-documented to have several physiological adaptations to support the energy demands of migration. However, even though mitochondria are the source of ATP that powers flight, the respiratory performance of the mitochondria is almost unstudied in the context of migration. We hypothesized that migratory species would have higher mitochondrial respiratory performance during migration compared to species that do not migrate. To test this hypothesis, we compared variables related to mitochondrial respiratory function between two confamilial bird species-the migratory Gray Catbird (Dumetella carolinensis) and the non-migratory Northern Mockingbird (Mimus polyglottos). Birds were captured at the same location along the Alabama Gulf Coast, where we assumed that Gray Catbirds were migrants and where resident Northern Mockingbirds live year-round. We found a trend in citrate synthase activity, which suggests that Gray Catbirds have a greater mitochondrial volume in their pectoralis muscle, but we observed no other differences in mitochondrial respiration or complex enzymatic activities between individuals from the migrant vs. the non-migrant species. However, when we assessed the catbirds included in our study using well-established indicators of migratory physiology, birds fell into two groups: a group with physiological parameters indicating a physiology of birds engaged in migration and a group with the physiology of birds not migrating. Thus, our comparison included catbirds that appeared to be outside of migratory condition. When we compared the mitochondrial performance of these three groups, we found that the mitochondrial respiratory capacity of migrating catbirds was very similar to that of Northern Mockingbirds, while the catbirds judged to be not migrating were lowest. One explanation for these observations is these species display very different daily flight behaviors. While the mockingbirds we sampled were not breeding nor migrating, they are highly active birds, living in the open and engaging in flapping flights throughout each day. In contrast, Gray Catbirds live in shrubs and fly infrequently when not migrating. Such differences in baseline energy needs likely confounded our attempt to study adaptations to migration.

Physiological plasticity and life history traits affect Chamelea gallina acclimatory responses during a marine heatwave

The striped venus clam (Chamelea gallina) is a relevant economic resource in the Adriatic Sea. This study explored the physiological status of C. gallina at four sites selected along a gradient from high to low incidence of recorded historical mortality events and low to high productivity in the Northwestern Adriatic Sea. Investigations were performed during the marine heatwave in 2022 (from July to November). The optimal temperature range for C. gallina was exceeded in July and September, exacerbating stress conditions and a poor nutritional status, particularly at the low productivity sites. Transcriptional profiles assessed in digestive glands showed that clams from the low productivity sites up-regulated transcripts related to feeding/digestive functions as a possible compensatory mechanism to withstand adverse environmental conditions. Clams from the high productivity sites, that in a previous study showed enrichment of health-promoting microbiome components, displayed a healthier metabolic makeup (IDH up-regulation) and induction of protective antioxidant and immune responses. These features are hallmarks of putative enhanced resilience of the species towards environmental stress. Despite the well-known high sensitivity of C. gallina to environmental variations and its narrow window of acclimatory potential, results highlight that local conditions may influence physiological plasticity of this clam species and shape either positively or negatively its response capabilities to environmental changes. The identification of health-promoting endogenous mechanisms both from the animal (this study) and from its associated microbiome may provide the foundation for developing novel tools and strategies to improve clam health and production in low productivity areas or under adverse environmental conditions.

The Acoustic Ecology of Coastal Dolphins by Assessing the Structural Variability of Sounds and the Influence of Contextual Factors

The acoustic ecology of a previously unexamined dolphin population in the Mediterranean was assessed by investigating how sound emissions and acoustic features are influenced by concurrent conditions. Whistles and click-trains emission rates were compared among different environmental, social and behavioural conditions. Structural variability of 3928 good/high-quality vocalizations was analysed in relation to contexts through a two-stage approach. First, two multivariate MANOVA-models were fitted considering the entire set of acoustic parameters extracted from whistles and click trains, to investigate the effect of concomitant factors on the overall acoustic structure of each vocalization. Subsequently, GLMM models were applied to each acoustic feature individually to explore its response to different contextual factors. Emission rates increased significantly with calves and in larger groups, with also a positive effect of socialization on whistles and of muddy/sandy seabed and depth on impulsive sounds. The multivariate approach showed that all contextual factors influenced sounds' structure, with whistles being strongly affected by behaviour and calves' presence. The GLMM models highlighted that each acoustic parameter varied differently in response to specific factors, with (1) increasing trends in whistles' duration and inflection points during interaction with fishery and decreasing ones during socializing, and (2) decreasing inter-click-intervals and increasing click-repetition-rates in larger groups and during interactions with fishery. These results provide new findings on the acoustic plasticity of bottlenose dolphins and a more comprehensive view of the magnitude of the social, environmental and behavioural influence, highlighting how the complexity of the species' acoustic repertoire has yet to be unravelled at the local level.

Morphological and ecological approaches in reproduction of the endemic catfish of the eastern Amazon

This study aimed to describe reproductive ecology based on morphological aspects of Peckoltia oligospila in stream rapids, eastern Amazon. A total of 186 fish (75 males and 111 females) were collected. The sex and gonadal maturity stage of these specimens were obtained based on histological characteristics of the gonads. The sex ratio, gonado-somatic index (GSI), relative frequency of the different maturity stages, size at first sexual maturation, condition factor of the population, and fluviometry were evaluated during the study. There was a significant female frequency during the study. The population exhibited positive allometric growth without differences between sexes. GSI and relative frequency showing a reproductive period synchronized in February, and the species exhibited parcelated spawning. L50 was estimated at 5.85 and 7.39 cm for females and males, respectively. There were significant differences in the condition factor only in females that showed a highest value in August. Thus, based on the results P. oligospila has an intermediate strategy between the opportunistic and equilibrium strategies.

Enzyme Inhibitory, Physicochemical, and Phytochemical Properties and Botanical Sources of Honey, Bee Pollen, Bee Bread, and Propolis Obtained from the Same Apiary

Bee products are an important source of nutrients and bioactive phytochemicals. This study aimed to determine the chemical composition (proximate composition, general phytochemical composition, sugar, and phenolic profiles) of four different products (honey, bee pollen, bee bread, and propolis), obtained from the same apiary, as well as to assess their biological activity through antioxidant and enzyme inhibition assays (α-amylase, α-glucosidase, lipase, AchE, neuraminidase, angiotensin-converting enzyme, urease, trypsin, tyrosinase, carbonic anhydrase, thioredoxin reductase, adenosine deaminase). Clear differences were observed among the samples in terms of both chemical composition and biological activity. The analysis revealed that bee pollen exhibited the highest carbohydrate content (87.9%), while propolis was identified as the richest source of phenolic compounds (14,858.9 mg/kg) among the analyzed samples. Propolis exhibited the highest biological activity in all applied antioxidant assays (CUPRAC, DPPH•, and ABTS•+) and in most enzyme inhibition assays. Notably, the α-glucosidase inhibition activity of propolis was comparable to that of the reference standard. In addition, honey exhibited remarkable trypsin inhibition, also comparable to the applied standard. These findings highlight the diverse bioactivities of hive products, which could play a key role in promoting health and preventing diseases.

A ubiquinone precursor analogue does not clearly increase the growth rate of Caenorhabditis inopinata

The evolution of developmental rates may drive morphological change. Caenorhabditis inopinata develops nearly twice as slowly as Caenorhabditis elegans . clk-1 encodes a hydroxylase required for synthesizing ubiquinone, and mutant clk-1 slow growth phenotypes can be rescued by supplying animals with a ubiquinone precursor analogue, 2,4-dihydroxybenzoate. RNA-seq data showing low clk-1 expression raised the possibility that C. inopinata grows slowly because of reduced ubiquinone biosynthesis. C. inopinata did not reveal a clear reduction in the age of maturation when reared on 2,4-dihydroxybenzoate. Further scrutiny of RNA-seq results revealed multiple ubiquinone metabolism genes have low expression in C. inopinata . Divergent clk-1 expression alone may not be a major driver of the evolution of slow development in this species.

Rediscovery of the Endangered Pseudophilotes fatma (Oberthür, 1890) (Lepidoptera: Lycaenidae) in Algeria after 71 years, with an update on its distribution and designation of a lectotype

Pseudophilotes fatma (Oberthür, 1890) is a Palearctic butterfly species endemic to the Maghreb region, characterised by a highly restricted distribution and "Endangered" conservation status. Recent field observations in Batna Province, northeastern Algeria, have documented new localities for P. fatma, marking its rediscovery after a 71-year absence. We updated the global distribution map for this species and highlight the urgent need for conservation actions to ensure its persistence. A lectotype is designated for Lycæna bavius var. fatma Oberthür, 1890.

Disparities in Perimyotis subflavus Body Mass Between Cave and Culvert Hibernacula in Georgia, USA

The tricolored bat (Perimyotis subflavus), once common in the eastern United States, has experienced significant mortality due to white-nose syndrome (WNS), a fungal disease that primarily affects bats hibernating in caves and mines. In coastal regions of the southeastern United States, where caves and mines are scarce, tricolored bats often use roadway culverts as hibernacula. However, WNS infection dynamics in culverts are poorly understood. Previous research indicated that bats with higher body mass at the onset of hibernation have a higher probability of surviving repeated arousal events from WNS. Therefore, we compared tricolored bat winter body mass between cave and culvert hibernacula and identified culvert characteristics influencing body mass during hibernation in Georgia, USA. From 2018 to 2022, we measured body mass of 754 individuals in early and late hibernation across 32 culverts (n = 497) and four caves (n = 257). Our study revealed a southward spread of the fungus over multiple years, with the first confirmed case of WNS in a Georgia culvert in 2022. Overall, tricolored bats in caves weighed more in early hibernation than those in culverts, but bats in culverts weighed more in late hibernation. Across all sites, female tricolored bats entering and leaving hibernation had greater mass than males but lost more mass during hibernation, possibly due to differences in torpor-arousal patterns and WNS infection rates. Additionally, all bats lost more mass in longer culverts. Understanding culvert characteristics affecting bat body mass will inform management strategies to mitigate WNS effects. Identifying risk factors for specific tricolored bat hibernacula can guide managers on where to focus winter WNS monitoring efforts and potential treatments.

Body size influences the capacity to cope with extreme cold or hot temperatures in the striped hamster

Body size of organisms is a key trait influencing nearly all aspects of their life history. Despite growing evidence of Bergmann's rule, there is considerably less known about the links between body size and the maximum capacity to thermoregulate of an animal in response to extreme cold or hot environment. Thermal characteristics such as resting metabolic rate (RMR) and non-shivering thermogenesis (NST), and the upper- and lower-critical temperatures of the thermal neutral zone (TNZ) were investigated in small and large body sized striped hamsters (Cricetulus barabensis). The maximum capacity to thermoregulate in response to extreme cold (-15 °C) or hot temperature (38 °C) was also examined, where both, different sized hamsters had similar RMR and NST regardless of temperature exposure. The large hamsters had 29.9% more body mass compared to small hamsters. The large hamsters showed a wider TNZ, with lower, lower-critical temperature, and showed considerable hyperthermia at the end of a 17-h hot exposure. In contrast, the small hamsters showed hypothermia following a 17-h cold exposure relative to large hamsters. In addition, the large hamsters showed 17.2% lower basal thermal conductance, and 14.9% lower maximum thermal conductance than the small hamsters after cold exposure, and 22.6% lower thermal conductance following heat exposure. Several molecular markers indicative of thermogenesis and oxidative stress did not differ significantly between the large and small hamsters. These findings suggest that individuals with larger body sizes have greater capacity to thermoregulate to cope with extreme cold, and a reduced capacity in response to extreme hot. In contrast, smaller individuals demonstrated the opposite trend. Body size may decide the capacity to thermoregulate to cope with extreme cold and heat, within which body heat dissipation is likely more important than heat production.

The Sixth Mass Extinction and Amphibian Species Sustainability Through Reproduction and Advanced Biotechnologies, Biobanking of Germplasm and Somatic Cells, and Conservation Breeding Programs (RBCs)

Primary themes in intergenerational justice are a healthy environment, the perpetuation of Earth's biodiversity, and the sustainable management of the biosphere. However, the current rate of species declines globally, ecosystem collapses driven by accelerating and catastrophic global heating, and a plethora of other threats preclude the ability of habitat protection alone to prevent a cascade of amphibian and other species mass extinctions. Reproduction and advanced biotechnologies, biobanking of germplasm and somatic cells, and conservation breeding programs (RBCs) offer a transformative change in biodiversity management. This change can economically and reliably perpetuate species irrespective of environmental targets and extend to satisfy humanity's future needs as the biosphere expands into space. Currently applied RBCs include the hormonal stimulation of reproduction, the collection and refrigerated storage of sperm and oocytes, sperm cryopreservation, in vitro fertilization, and biobanking of germplasm and somatic cells. The benefits of advanced biotechnologies in development, such as assisted evolution and cloning for species adaptation or restoration, have yet to be fully realized. We broaden our discussion to include genetic management, political and cultural engagement, and future applications, including the extension of the biosphere through humanity's interplanetary and interstellar colonization. The development and application of RBCs raise intriguing ethical, theological, and philosophical issues. We address these themes with amphibian models to introduce the Multidisciplinary Digital Publishing Institute Special Issue, The Sixth Mass Extinction and Species Sustainability through Reproduction Biotechnologies, Biobanking, and Conservation Breeding Programs.