Search Results (657)

The microtubule-associated protein tau, encoded by the MAPT gene, serves as a major component of the neuronal cytoskeleton, facilitating the assembly, stabilization, and spatial organization of microtubules. Much of the work on tau has focused on the low-molecular-weight (LMW) isoforms abundantly expressed in the central nervous system (CNS) and their pathological aggregation in tauopathies. However, a different variant known as “Big tau”, present in the peripheral nervous system (PNS) and selective CNS regions has distinct structural and functional properties and offers a unique perspective on protein evolution. Big tau is characterized by the inclusion of a large, alternatively spliced insert termed exon 4a, which expands the protein’s projection domain by approximately 250 amino acids and increases the molecular weight to 90–110 kDa. The evolutionary trajectory of exon 4a presents a fascinating enigma that challenges conventional models of protein conservation. Across the vertebrate phylogeny, spanning from fishes, amphibians and birds to mammals, the primary amino acid sequence of exon 4a exhibits extreme divergence, often reaching background levels of identity when comparing distant classes. In contrast, the physical length of this domain remains remarkably stable, hovering around the 250-amino acid mark regardless of the species. This pattern suggests that the selective pressure acting on Big tau is not directed toward specific sequence motifs or functional domains, but rather toward the biophysical properties and physical dimensions of the domain. Here, we posit that exon 4a evolved as an essential molecular spacer optimized for the structural demands of long-projection neurons and high-caliber axons as well as a protective structure for the pathologic aggregation of tau. The paper examines the genomic architecture and biophysical identity underlying the stable-size and low sequence identity of exon 4a, presenting two evolutionary mechanisms as working hypotheses: a Prototype Model of neutral drift of an ancient insert, and an Independent Exonization of convergent recruitment of non-coding DNA by transposable elements or intron retention. Finally, we emphasize the need for additional experimental work in vitro and in vivo to resolve unanswered questions about the structure of the 4a exon, the physiological role Big tau and its potential insight into tauopathies therapeutics. Full article

Death feigning (thanatosis) is the antipredator behaviour of grass snake (Natrix natrix) which can contribute to its survival. Since this is difficult to study under natural conditions, in our experiment we used four types of plasticine models of grass snake to mimic its different behaviour types. The advantage of using plasticine models is that they preserve the traces of the predators. The study was conducted at two different locations in Kis-Balaton, one of the largest wetlands in the Carpathian Basin. Only 8.75% (n = 21) of all grass snake models (n = 240) were damaged by predators. The predation activity of birds (76%) was significantly higher than that of mammals (24%), the latter left imprints only on models imitating live (uncoiled, coiled) grass snakes. Among predated models, 62% showed injuries on the midbody, 24% on the tail tip, and 14% on the head. Predation rates were similar in spring and autumn periods, and on the abandoned railway and road. Comparisons of daily survival rates between different model types suggested that the coiled (basking and death feigning) pose may provide an advantage in survival. In some cases, the visible colour pattern of the models may have affected their detectability. The higher survival rates of the grass snake models imitating death feigning indicate the adaptive value of this antipredator behaviour. Full article

Irisin is a myokine derived from fibronectin type III domain-containing protein 5 (FNDC5) and is involved in energy metabolism, muscle development, and oxidative regulation. Although irisin has been extensively studied in mammals, its potential application in poultry production remains unclear. Enhancing growth performance and physiological resilience is critical for male white-feathered broiler chickens under intensive production systems. This study investigated the effects of dietary irisin supplementation on growth performance and physiological responses in male white-feathered broiler chickens. A total of 180 broilers were randomly allocated to three treatments, with six replicate pens of ten birds per treatment: basal diet and basal diet supplemented with 5 and 10 mg/kg irisin for 42 days. At 42 days, one bird from each replicate pen was sampled for carcass, meat-quality, serum, immune, and microbiota analyses. Dietary irisin supplementation significantly increased final body weight and average daily gain compared with the control group. Feed conversion ratio decreased from 1.51 in the control group to 1.46 in the 5 and 10 mg/kg groups. Carcass evaluation showed higher slaughter yield and breast muscle yield in irisin-supplemented birds, and cooking loss was significantly reduced in both breast and thigh muscles. Serum superoxide dismutase (SOD) activity was elevated in irisin-treated groups. In addition, immunoglobulin Y (IgY) and immunoglobulin M (IgM) concentrations were significantly increased. No significant treatment effects were observed for total antioxidant capacity (T-AOC), catalase (CAT), malondialdehyde (MDA), inflammatory cytokines (IL-6, TNF-α), or immune organ indices (thymus, spleen and bursa of Fabricius). Gut microbiota analysis showed numerical differences in the relative abundance of several major bacterial taxa among treatments. In conclusion, dietary irisin supplementation was associated with improved growth performance and selected carcass, meat-quality, antioxidant, immunoglobulin, and cecal microbiota outcomes in male white-feathered broiler chickens, supporting further investigation of its potential as a functional feed additive in poultry nutrition. Full article

Wildlife plays a vital role in maintaining ecological balance and biodiversity, relying on habitats that provide shelter, food, and essential resources. This study investigated wildlife distribution and diversity across the REDD+ program area in Cambodia’s Prey Lang Wildlife Sanctuary, a lowland evergreen forest ecosystem, and assessed the effects of forest habitats and anthropogenic pressure on their distribution. We used square transects for sampling and ArcGIS to calculate forest cover and distance to the nearest village as a proxy for human impact. Overall, we recorded seven mammals and two birds, with the great hornbill (Buceros bicornis) most frequently detected, followed by pileated gibbon (Hylobates pileatus), wild pig (Sus scrofa), long-tailed macaque (Macaca fascicularis), green peafowl (Pavo muticus), northern red muntjac (Muntiacus vaginalis), and Indochinese silvered langur (Trachypithecus germaini), while gaur (Bos gaurus) and sambar deer (Rusa unicolor) were least detected. Wildlife richness and abundance were higher in evergreen-dominated habitats than in mixed deciduous–evergreen forests. Certain K-selected species, including pileated gibbon, Indochinese silvered langur, and great hornbill, were highly specialized and preferred intact forests, whereas generalist species such as northern red muntjac, long-tailed macaque, and wild pig showed ecological flexibility in habitat use. These findings emphasize tailored conservation strategies: protecting intact evergreen forests via REDD+ supports specialized species, while adaptive management in mosaic landscapes benefits generalists, enhancing wildlife conservation and sustainable management of the Prey Lang Wildlife Sanctuary. Full article

Urban grey infrastructure, including transport corridors, flood-control systems, drainage facilities, railway margins, and industrial brownfields, is often treated in conventional planning as functionally vacant or ecologically marginal space. In this study, grey infrastructure is defined as engineered or infrastructure-dominated urban spaces and their residual or edge landscapes, rather than as green infrastructure. Yet such spaces may still contain spontaneous vegetation, water edges, soil patches, and sheltered microhabitats that can support birds, insects, small mammals, and other urban species in highly urbanized environments. From a multispecies justice perspective, this study examines spatial mismatches between PPGIS-derived public recognition and habitat quality modeled using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model in urban grey infrastructure. Using Zhanggong District, Ganzhou, China, as a case study, we developed an integrated framework that combines public participation geographic information systems (PPGIS), grid-based public recognition mapping, and the InVEST Habitat Quality model. Based on 260 valid questionnaires, participants identified locations associated with aesthetic preference and perceived habitat potential. These mapped perception points were converted into a grid-based public recognition indicator and compared with modeled habitat quality. The results indicate a marked perception-habitat mismatch. High public recognition was frequently associated with visually ordered, accessible, and highly managed urban spaces, whereas high modeled habitat quality was more strongly related to vegetated, riverine, peripheral, and semi-natural spaces. The spatial classification shows that aesthetic mismatch areas, where public recognition was high but modeled habitat quality was low, covered 43.20 km², accounting for 7.16% of the study area, whereas hidden ecological value areas, where modeled habitat quality was high but public recognition was low, covered 118.21 km², accounting for 19.59%. This study provides a replicable framework for identifying perception–habitat mismatches and supports more ecologically informed and inclusive strategies for regenerating urban grey infrastructure. More specifically, the study extends an established perception-ecology debate to grey infrastructure and residual urban spaces and demonstrates how PPGIS-derived public recognition and InVEST-modeled habitat quality can be compared within the same grid framework to locate spatially explicit alignment and mismatch. Full article

Rotaviruses (RVs) are important pathogens which induce gastroenteritis in different kinds of animals, including mammals and birds. Rotaviruses are divided into nine species (RVA-RVD and RVF-RVJ), and RVA-RVC and RVH can infect both humans and pigs. It is vital to understand the genetic diversity and evolution of porcine rotavirus (PoRV) for effective prevention and control of this disease. In this study, 5320 intestinal tissue samples and fecal swabs were collected from different pig farms in Guangxi Province, southern China, from 2022 to 2025. These samples were tested for PoRV species A (PoRVA), PoRVB, PoRVC, and PoRVH using the multiplex RT-qPCR. The positive samples of PoRVA were further selected to amplify and analyze the VP4, VP6, and VP7 gene sequences. The phylogenetic trees were constructed based on the PoRVA VP4, VP6, and VP7 gene sequences. Bayesian time-dynamic analysis and recombination analysis were performed for the PoRVA VP4 gene. The results indicated that the PoRVA, PoRVB, PoRVC, and PoRVH positivity rates were 16.92% (900/5320), 0.51% (27/5320), 12.71% (676/5320), and 6.22% (331/5320), respectively. Fifty-two VP4, VP6, and VP7 gene sequences were obtained from the 52 selected PoRVA-positive clinical samples. The nucleotide and amino acid identity analysis of the obtained PoRVA VP4, VP6, and VP7 genes indicated that the genetic diversity of the VP4 gene was higher than that of the VP6 and VP7 genes. The phylogenetic trees based on the VP4, VP6, and VP7 genes revealed that the predominant strains of PoRVA in Guangxi Province were the G9P[13]I5 genotype. Bayesian analysis indicated that the population size of PoRVA kept steady with no significant expansion from its discovery in the 1970s to approximately 2016, then exhibited gradual growth. Sequence analysis of the PoRVA VP4 gene revealed substitutions and recombination in the PoRVA strains, and one strain was derived from recombination of a porcine-originating strain and a human-originating strain. This study provided useful information on the molecular characteristics and genetic diversity of PoRVA and supplied important clues for in-depth research on the cross-species transmission of PoRVA. Full article

Sarcocystis spp. are apicomplexan parasites with an obligatory two-host prey–predator life cycle. While the intermediate hosts (IHs) of many species are well known, the definitive hosts (DH) of numerous Sarcocystis spp., especially those involving wildlife predators, remain poorly understood. In the current study, Sarcocystis species richness was investigated in the intestines of 69 red foxes (Vulpes vulpes) from Lithuania. Intestinal samples were examined by light microscopy and nested PCR targeting the cytochrome c oxidase I gene (cox1) sequence of species associated with ungulate IH and the internal transcribed spacer I (ITS1) region of species using birds as IH, followed by Sanger sequencing and phylogenetic analyses. Red foxes harboured a broad spectrum of Sarcocystis species, with those utilising ungulate IHs being considerably more common than species associated with birds. Seven species, Sarcocystis alces, Sarcocystis bertrami, Sarcocystis capreolicanis, Sarcocystis hjorti, Sarcocystis iberica, Sarcocystis linearis, and Sarcocystis morae, were identified in red foxes for the first time. Nine previously reported species, Sarcocystis albifronsi, Sarcocystis arieticanis, Sarcocystis capracanis, Sarcocystis cruzi, Sarcocystis gracilis, Sarcocystis miescheriana, Sarcocystis pilosa, Sarcocystis rileyi, and Sarcocystis tenella, were also detected. In addition, two potentially novel Sarcocystis taxa were identified and warrant further investigation. These findings highlight the role of red foxes as an important DH and provide a valuable framework for comparative studies of Sarcocystis distribution in predatory mammals. Full article

The H5N1 highly pathogenic avian influenza (HPAI) virus has caused severe global losses, reaching South America in 2022 and Antarctica in 2024. Here, we synthesize outbreak reports submitted to the World Organization for Animal Health by South American countries and overseas territories in this continent, and document the virus’s unprecedented expansion into Antarctica, affecting wild birds, wild mammals, and domestic poultry. Phylogenetic and time-calibrated Bayesian analyses were performed on available genomic sequences. Over 6 million domestic birds were lost, mostly from commercial operations. Of the 11 South American countries and overseas territories that reported H5N1 to WOAH, 10 reported infections in wild birds, spanning 104 species, 59.62% of which are migratory and predominantly non-trans-equatorial. Marine mammal outbreaks followed wild bird detections, with the South American sea lion (Otaria flavescens) being the most reported species. Several Antarctic bird species with migratory behavior were also reported in South America. Genomic analyses revealed multiple introduction events, regional viral diversification, and patterns consistent with repeated cross-species spillover events. These findings highlight H5N1’s extensive ecological reach in the Southern Hemisphere and underscore the urgent need for a One Health approach that strengthens wildlife and backyard-poultry surveillance, alongside coordinated regional action to control and prevent further HPAI spread. Full article

Wild waterfowl constitute the primary natural reservoir of influenza A viruses, and wetlands at the convergence of major migratory flyways serve as critical hubs for viral genetic exchange. Baikal Siberia, situated at the intersection of the East African–West Asian, Central Asian, and East Asian–Australasian flyways, represents a unique yet understudied region in this context. Here we report the results of long-term virological surveillance of wild birds in the Lake Baikal basin conducted between 2018 and 2024. A total of 1036 cloacal swab samples from 28 bird species were screened, yielding 42 influenza A virus isolates belonging to 12 HA/NA subtype combinations: H1N1, H3N1, H3N2, H3N5, H3N6, H3N8, H4N6, H6N1, H6N2, H6N3, H6N8, and H12N5. Among the detected subtypes, H6 viruses—identified with four distinct neuraminidase combinations (N1, N2, N3, N8)—are of particular public health relevance owing to their documented capacity for dual-receptor binding and potential for zoonotic transmission to mammals, including humans. Full-genome sequencing followed by cluster analysis of internal gene segments identified 16 distinct segment constellations, indicating extensive reassortment. BLAST searches against the GISAID database revealed closest genetic relatives in Mongolia, South Korea, Japan, China, and Western Siberia, with more distant links to Bangladesh, Europe, and a possible intercontinental connection via the Pacific flyway. Maximum-likelihood phylogenetic analysis of the HA and NA segments confirmed that all isolates belong to the Eurasian genetic lineage, yet they are distributed across multiple clades rather than forming a single monophyletic group, reflecting the role of Buryatia as a mixing zone for genetically diverse viral populations. These findings substantially expand the understanding of influenza A virus ecology in the Lake Baikal basin and underscore the importance of continued surveillance at this key migratory crossroads in Northern Asia. Full article

Detailed knowledge of biodiversity is fundamental to supporting conservation and management strategies in protected natural areas, especially in mountain systems located in biogeographic transition zones (Chihuahuan Desert and Sierra Madre Oriental regions). The Sierra de Zapalinamé State Natural Reserve is a priority system in northeastern Mexico; however, comprehensive long-term inventories of its terrestrial vertebrate fauna have been limited. The objective of this study was to comprehensively characterize the richness and composition of the terrestrial vertebrate fauna of the Sierra de Zapalinamé State Natural Reserve using a long-term, multi-source dataset integrating systematic field surveys, biological collections, and citizen science records, and to assess the extent to which the reserve represents the vertebrate diversity of northeastern Mexico. A total of 415 terrestrial vertebrate species were recorded, comprising 299 birds, 67 mammals, 42 reptiles, and 7 amphibians. Despite its proximity to urban areas and industrial activities, the reserve maintains high levels of biodiversity, harboring a substantial proportion of the terrestrial vertebrate fauna of northeastern Mexico. The results emphasize the importance of the Sierra de Zapalinamé State Natural Reserve as a regional biodiversity hotspot and support the strengthening of long-term monitoring and management strategies to improve wildlife conservation in underrepresented ecoregions facing increasing environmental pressures. Full article

Avian influenza viruses (AIVs) are widely distributed and have a wide range of hosts. Recently, the number of cases of infection associated with the circulation of highly pathogenic avian influenza H5N1 2.3.4.4b has raised concerns about its high transmission capacity in birds and mammals. This study analyzed swabs from bird and mammal species from the coast of Paraná and the northwest region of São Paulo, Brazil, for the presence of AIV in animals that did not present clinical or histopathological lesions of infection that indicated the need for molecular characterization during monitoring. Of the 661 animals analyzed, three tested positive, two of which were birds (Sula leucogaster and Thalasseus acuflavidus) while one was a mammal (Otaria flavescens) (0.45%, CI 95%: 0.16–1.33). A complete genome sequence of H5N1 AIV was obtained from a brown booby (Sula leucogaster) from the Paraná coast (GISAID accession number: EPI_ISL_1897537). Our study reinforces the importance of continuous genomic surveillance, especially in AIV hosts that do not show signs of infection, to enhance the One-Health assessment approach. Full article

Heat shock proteins of the 70 kDa family (HSP70s) are essential molecular chaperones that preserve proteostasis by assisting protein folding, transport, and degradation. Although the core HSP70 architecture is deeply conserved, the degree and functional significance of sequence divergence across vertebrates remain incompletely understood. Here, an integrative comparative analysis of HSP70 proteins from ten representative vertebrate species spanning mammals, birds, amphibians, and teleost fish was performed. Multiple sequence alignment, phylogenetic reconstruction, motif discovery, entropy-based conservation profiling, hydrophobicity analysis, and structural mapping reveal a strikingly conserved ATPase domain alongside a more variable substrate-binding domain and C-terminal region. Multiple Expectation Maximization for Motif Elicitation (MEME) motif analysis identifies both universally conserved motifs and lineage-specific elements, highlighting functional constraint as well as adaptive diversification. Structural projection onto the human HSP70 crystal structure (PDB 5AQV) demonstrates that conserved hydrophobic residues cluster in the protein core, whereas variable residues are predominantly surface-exposed. Together, these findings illuminate how evolutionary pressures shape both the conserved chaperone machinery and flexible regulatory regions of HSP70, and they establish a scalable analytical framework for comparative protein evolution studies. Full article

The role of birds of the Strigiformes order in the transmission of globally distributed Sarcocystis parasites remains insufficiently studied. In the present work we aimed to evaluate the diversity of Sarcocystis species in the intestines of 22 naturally infected Tawny Owls (Strix aluco) sampled in Lithuania. The Sarcocystis infection was established using combined light microscopy and DNA sequence analysis. Samples were analyzed using Sarcocystis-genus and species-specific primers in nested PCR followed by Sanger sequencing. Sporocysts of Sarcocystis spp. were detected in 45.5% of samples, while 77.3% of samples were positive by molecular methods. Comparison of 28S rRNA and ITS1 sequences obtained and phylogenetic analyses indicated the presence of eight Sarcocystis taxa: S. halieti, S. kutkienae, S. turdusi, and Sarcocystis sp. ex Corvus corax, associated with birds, and S. funereus, S. glareoli, Sarcocystis sp. LT24Sa1, and Sarcocystis sp. LT24Sa11, associated with small mammals. Our results supplement previous findings that some Sarcocystis species can be transmitted by birds of three orders: Accipitriformes, Falconiformes, and Strigiformes. Overall, the low burden of sporocysts and predominance of single-species infections (63.6%) suggest that Tawny Owls transmit a limited number of Sarcocystis species associated with small mammals and birds. Full article

Background/Objectives: Healthy animals can harbor complex and diverse bacterial communities, including pathogenic taxa capable of causing disease and mortality, and individuals that are kept in zoos may act as asymptomatic carriers of a broad range of pathogens. Therefore, this study aimed to investigate the rectal bacterial microbiota of multiple animal classes (reptiles, birds, and mammals), maintained in enclosures, identify known or emerging bacterial pathogens, and characterize the antibiotic resistance profiles of the isolated strains. Methods: A total of 40 samples were collected by rectal swabbing for bacteriological analysis from 31 different animal species living in enclosures in four Algerian zoos. The isolated and identified bacterial strains were tested against certain antibiotics used in human and veterinary medicine. Statistical analyses were performed to assess differences in bacterial isolation among animal classes, sex, age categories, and zoological facilities, as well as the degree of similarity between isolated strains based on their antibiotic resistance profiles. Results: A total of 94 bacterial isolates were recovered from 40 fecal samples. Overall, the bacterial isolates belonged to seven families, 13 genera, and 16 taxa. The families identified were Enterobacteriaceae (50/94; 53.19%), Staphylococcaceae (28/94; 29.78%), Pseudomonadaceae (6/94; 6.38%), Brucellaceae (2/94; 2.12%), Morganellaceae (4/94; 4.25%), Yersiniaceae (3/94; 3.19%), and Erwiniaceae (1/94; 1.06%). Reptiles accounted for the highest number of isolates (37/94; 39.36%), followed by 31/94 isolates (32.97%) for birds and 26/94 isolates (27.65%) for mammals. The highest resistance rates were observed for ampicillin (AMP; 95.73%), followed by amoxicillin/clavulanic acid (AMC; 75.54%) and cephalothin (CEP; 44.90%). Lower resistance rates were detected for trimethoprim–sulfamethoxazole (SXT; 18.87%), cefotaxime (CTX; 17.41%), ceftazidime (CX; 13.67%), ciprofloxacin (CIP; 6.38%), and gentamicin (GEN; 1.05%). Conclusion: This study shows the first report that vertebrates in Algerian zoos can harbor a diverse range of cultivable bacteria, often with polymicrobial carriage. Antimicrobial resistance patterns were generally consistent with commonly used veterinary drugs. Overall, these findings contribute to a better understanding of the composition of rectal bacterial carriage in zoos. Full article

In 2022, the World Health Organization (WHO) published the Fungal Priority Pathogens List (FPPL), yet its application has remained largely focused on human medicine, with limited consideration of animal hosts and veterinary diagnostics. This retrospective study aimed to characterise the occurrence of WHO critical- and high-priority yeasts in veterinary clinical submissions in Portugal within an explicit One Health framework. All yeast-positive submissions received by a Portuguese veterinary diagnostic laboratory between 2019 and 2026 were reviewed. Isolates were identified phenotypically, by an automated identification system and by MALDI-TOF mass spectrometry. Data on host species, sample type and year of submission were analysed using standard descriptive and inferential statistics. Among 2033 mycological submissions, 219 were yeast-positive. Out of these, 82 isolates (37.4%) corresponded to WHO critical- or high-priority taxa, most frequently Candida albicans, followed by Nakaseomyces glabratus, Cryptococcus neoformans var. neoformans, the Candida parapsilosis complex and Candida tropicalis. The remaining 137 isolates (62.6%) corresponded to non-WHO taxa, among which the most frequent were Papiliotrema laurentii and Debaryomyces hansenii (n = 21 each; 15.3%), followed by the Stephanoascus ciferrii complex (n = 15; 11.0%), Meyerozyma guilliermondii and Candida sake (n = 12 each; 8.8%), and Wickerhamomyces anomalus (n = 9; 6.6%). WHO-prioritised taxa were recovered predominantly from ornamental birds, as well as from dogs, cats and marine mammals. These findings demonstrate that FPPL-listed yeasts are regularly detected among yeast-positive veterinary diagnostic submissions and highlight ornamental birds as prominent hosts within this dataset. Full article