A cyst-forming coccidian with large geographical range infecting forest and commensal rodents: Sarcocystis muricoelognathis sp. nov.

BACKGROUND: The geographic distribution and host-parasite interaction networks of Sarcocystis spp. in small mammals in eastern Asia remain incompletely known. METHODS: Experimental infections, morphological and molecular characterizations were used for discrimination of a new Sarcocystis species isolated from colubrid snakes and small mammals collected in Thailand, Borneo and China. RESULTS: We identified a new species, Sarcocystis muricoelognathis sp. nov., that features a relatively wide geographic distribution and infects both commensal and forest-inhabiting intermediate hosts. Sarcocystis sporocysts collected from rat snakes (Coelognathus radiatus, C. flavolineatus) in Thailand induced development of sarcocysts in experimental SD rats showing a type 10a cyst wall ultrastructure that was identical with those found in Rattus norvegicus from China and the forest rat Maxomys whiteheadi in Borneo. Its cystozoites had equal sizes in all intermediate hosts and locations, while sporocysts and cystozoites were distinct from other Sarcocystis species. Partial 28S rRNA sequences of S. muricoelognathis from M. whiteheadi were largely identical to those from R. norvegicus in China but distinct from newly sequenced Sarcocystis zuoi. The phylogeny of the nuclear 18S rRNA gene placed S. muricoelognathis within the so-called S. zuoi complex, including Sarcocystis attenuati, S. kani, S. scandentiborneensis and S. zuoi, while the latter clustered with the new species. However, the phylogeny of the ITS1-region confirmed the distinction between S. muricoelognathis and S. zuoi. Moreover, all three gene trees suggested that an isolate previously addressed as S. zuoi from Thailand (KU341120) is conspecific with S. muricoelognathis. Partial mitochondrial cox1 sequences of S. muricoelognathis were almost identical with those from other members of the group suggesting a shared, recent ancestry. Additionally, we isolated two partial 28S rRNA Sarcocystis sequences from Low's squirrel Sundasciurus lowii that clustered with those of S. scandentiborneensis from treeshews. CONCLUSIONS: Our results provide strong evidence of broad geographic distributions of rodent-associated Sarcocystis and host shifts between commensal and forest small mammal species, even if the known host associations remain likely only snapshots of the true associations.

A recent gibbon ape leukemia virus germline integration in a rodent from New Guinea.

Germline colonization by retroviruses results in the formation of endogenous retroviruses (ERVs). Most colonization's occurred millions of years ago. However, in the Australo-Papuan region (Australia and New Guinea), several recent germline colonization events have been discovered. The Wallace Line separates much of Southeast Asia from the Australo-Papuan region restricting faunal and pathogen dispersion. West of the Wallace Line, gibbon ape leukemia viruses (GALVs) have been isolated from captive gibbons. Two microbat species from China appear to have been infected naturally. East of Wallace's Line, the woolly monkey virus (a GALV) and the closely related koala retrovirus (KoRV) have been detected in eutherians and marsupials in the Australo-Papuan region, often vertically transmitted. The detected vertically transmitted GALV-like viruses in Australo-Papuan fauna compared to sporadic horizontal transmission in Southeast Asia and China suggest the GALV-KoRV clade originates in the former region and further models of early-stage genome colonization may be found. We screened 278 samples, seven bat and one rodent family endemic to the Australo-Papuan region and bat and rodent species found on both sides of the Wallace Line. We identified two rodents (Melomys) from Australia and Papua New Guinea and no bat species harboring GALV-like retroviruses. Melomys leucogaster from New Guinea harbored a genomically complete replication-competent retrovirus with a shared integration site among individuals. The integration was only present in some individuals of the species indicating this retrovirus is at the earliest stages of germline colonization of the Melomys genome, providing a new small wild mammal model of early-stage genome colonization.

Tissue-resident macrophages specifically express Lactotransferrin and Vegfc during ear pinna regeneration in spiny mice.

The details of how macrophages control different healing trajectories (regeneration vs. scar formation) remain poorly defined. Spiny mice (Acomys spp.) can regenerate external ear pinnae tissue, whereas lab mice (Mus musculus) form scar tissue in response to an identical injury. Here, we used this dual species system to dissect macrophage phenotypes between healing modes. We identified secreted factors from activated Acomys macrophages that induce a pro-regenerative phenotype in fibroblasts from both species. Transcriptional profiling of Acomys macrophages and subsequent in vitro tests identified VEGFC, PDGFA, and Lactotransferrin (LTF) as potential pro-regenerative modulators. Examining macrophages in vivo, we found that Acomys-resident macrophages secreted VEGFC and LTF, whereas Mus macrophages do not. Lastly, we demonstrate the requirement for VEGFC during regeneration and find that interrupting lymphangiogenesis delays blastema and new tissue formation. Together, our results demonstrate that cell-autonomous mechanisms govern how macrophages react to the same stimuli to differentially produce factors that facilitate regeneration.

Dietary habits of lesser bandicoot rat (Bandicota Bengalensis) in an agro-ecosystem, Pothwar Plateau, Pakistan / Hábitos alimentares de rato bandicoot (Bandicota Bengalensis) em um agroecossistema do Planalto de Pothwar, Paquistão

Abstract Dietary habits of bandicoot rats (bandicota bengalensis) were investigated in the agricultural crops of the Pothwar Plateau, Pakistan by analysing stomach contents. The research activities were conducted in major field crops including wheat-groundnut and in the fallow lands during non-crop season at the field boundaries. The specimens were captured from the fields using kill/snap traps, and dissected to collect their stomach samples for laboratory analysis. Light microscopic slides of the plant material were recovered from stomach samples and the reference materials were collected from the field. Results revealed that the bandicoot rat predominantly fed upon cultivated crops during cropping season but consumed wild vegetation during non-cropping season. There was no significance difference between summer and winter diets. Most frequently consumed crop food items were wheat (Triticum aestivum; 28.57%), groundnut (Arachis hypogea; 11.26%), sorghum (Sorghum bicolor; 10.17%), chickpea (Cicer arietinum; 9.52%), maize (Zea mays; 6.49%), millet (Pennisetum glaucum; 5.84%), barley (Hordeum vulgare; 4.98%) and mustard (Brassica campestris; 4.98%). Among wild vegetation were consumed khbal gha (Cynodon dactylon; 7.79%), baron dhab (Demostachya bipinnata; 7.36%) and Prickly flower (Achyranthes aspera; 3.03%). The study concludes that, in addition to consuming wheat and groundnut crops, the Lesser bandicoot rat also subsists on grasses, weeds, and some fodder crops, as important component of its diet in agro-ecosystem of the Pothwar Plateau.

Resumo Os hábitos alimentares de ratos bandicoot (Bandicota bengalensis) foram investigados nas plantações agrícolas do planalto de Pothwar, Paquistão, por meio da análise do conteúdo estomacal. As atividades da pesquisa foram conduzidas nas principais culturas de campo, incluindo trigo e amendoim, e em terras de pousio durante a estação não agrícola nos limites do campo. Os espécimes foram capturados dos campos usando armadilhas kill/snap e dissecados para coletar suas amostras de estômago para análise laboratorial. Lâminas de microscopia de luz do material vegetal foram recuperadas de amostras de estômago; os materiais de referência foram coletados no campo. Os resultados revelaram que o rato bandicoot alimentava-se predominantemente de culturas cultivadas durante a época de cultivo, mas consumia vegetação selvagem durante a época de não colheita. Não houve diferença significativa entre as dietas de verão e inverno. Os alimentos agrícolas mais frequentemente consumidos foram trigo (Triticum aestivum; 28,57%), amendoim (Arachis hypogea; 11,26%), sorgo (Sorghum bicolor; 10,17%), grão de bico (Cicer arietinum; 9,52%), milho (Zea mays; 6,49%), milheto (Pennisetum glaucum; 5,84%), cevada (Hordeum vulgare; 4,98%) e mostarda (Brassica campestris; 4,98%). Entre a vegetação silvestre foram consumidos khbal gha (Cynodon dactylon; 7,79%), barão dhab (Demostachya bipinnata; 7,36%) e flor espinhosa (Achyranthes aspera; 3,03%). O estudo conclui que, além de consumir culturas de trigo e amendoim, o rato bandicoot pequeno também subsiste de gramíneas, ervas daninhas e algumas culturas forrageiras, componentes importantes de sua dieta no agroecossistema do planalto de Pothwar.

Bartonella raoultii sp. nov., isolated from infected rodents (Mastomys erythroleucus) in Senegal.

Bartonella species are involved in various human diseases, causing a range of clinical manifestations; animals are considered as the main reservoirs, transmitting diverse species of Bartonella through direct contact and haematophagous insects. Here, we characterize a new species, Bartonella raoultii sp. nov., within the genus Bartonella, using a taxonogenomic polyphasic approach. Strain 094T (= CSUR B1097T=DSM 28004T), isolated from the blood of an infected rodent (Mastomys erythroleucus) in Senegal, is an aerobic and rod-shaped bacterium. The annotated non-contiguous genome sequence is 1 952322 bp long and contains 37.2 mol% G+C content, 1686 protein-coding genes and 50 RNA genes, including seven rRNA genes.

Environmental pollution and nutritional quality modulate immune response of the wood mouse (Apodemus sylvaticus) through hormonal disturbances.

Cadmium (Cd) and lead (Pb) are known to enhance immune cell damages and to decrease cellular immunity, promoting higher susceptibility to infectious diseases. Selenium (Se) is an essential element involved in immunity and reactive oxygen species scavenging. This study aimed at evaluating how Cd and Pb and low nutritional (Se) quality modulate immune response to a bacterial lipopolysaccharide (LPS) challenge in wood mice (Apodemus sylvaticus). Mice were trapped near a former smelter in northern France in sites of High or Low contamination. Individuals were challenged immediately after capture or after five days of captivity, fed a standard or a Se-deficient diet. Immune response was measured with leukocyte count and plasma concentration of TNF-α, a pro-inflammatory cytokine. Faecal and plasma corticosterone (CORT), a stress-hormone involved in anti-inflammatory processes, was measured to assess potential endocrine mechanisms. Higher hepatic Se and lower faecal CORT were measured in free-ranging wood mice from High site. LPS-challenged individuals from High site showed steeper decrease of circulating leukocytes of all types, higher TNF-α concentrations, and a significant increase of CORT, compared to individuals from Low site. Challenged captive animals fed standard food exhibited similar patterns (decrease of leukocytes, increase of CORT, and detectable levels of TNF-α), with individuals from lowly contaminated site having higher immune responses than their counterparts from highly polluted site. Animals fed Se-deficient food exhibited lymphocytes decrease, no CORT variation, and average levels of TNF-α. These results suggest (i) a higher inflammatory response to immune challenge in free-ranging animals highly exposed to Cd and Pb, (ii) a faster recovery of inflammatory response in animals lowly exposed to pollution when fed standard food than more exposed individuals, and (iii) a functional role of Se in the inflammatory response. The role of Se and mechanisms underlying the relationship between glucocorticoid and cytokine remain to be elucidated.

Cryptic species Hydatigera kamiyai and other taeniid metacestodes in the populations of small mammals in Serbia.

BACKGROUND: Hydatigera (Cestoda: Taeniidae) is a recently resurrected genus with the description of a new species, Hydatigera kamiyai, a cryptic entity within the Hydatigera taeniaeformis species complex. Rodents are intermediate hosts and correct taxonomic identification of H. taeniaeformis sensu lato (s.l.) species is difficult without the use of molecular methods. The aim of this study was to identify and explore the genetic diversity of Hydatigera and other taeniid species. METHODS: Ten different small mammals species (856 individuals) (Rattus rattus, three Apodemus, three Arvicolinae and three Soricidae species) were examined from 2013 to 2023. Captured animals were visually examined for cysts and visible lesions. Two markers were used for amplification and sequencing: cox1 and 12S rDNA. RESULTS: Molecular analysis of cysts and visible lesions revealed four taeniid species: Hydatigera kamiyai, H. taeniaeformis sensu stricto (s.s.), Taenia martis and T. crassiceps. Hydatigera kamiyai was found in Apodemus flavicollis, A. agrarius, Microtus arvalis and Crocidrua leucodon, while H. taeniaeformis s.s. is registered in R. rattus. Hydatigera kamiyai cox1 sequences clustered with European populations and showed at least 25 nucleotid differences compared to Asian, African, Australian and one of our isolates of H. taeniaeformis s.s acquired from a rat, followed by large sequence distances (9.4% to 12.9%), indicating clear molecular distinction of two species. CONCLUSIONS: This is one of the few mitochondrial gene-based studies performed after the description of cryptic entities within the Hydatigera taeniaeformis s.l. complex and represents a valuable contribution to understanding of genetic diversity, host suitability and geographic distribution of these tapeworm species. Also, our study provides an important basis of molecular data from this part of Europe for further studies. We emphasize the importance of additional studies of intermediate hosts, especially rats from Europe and Apodemus spp. and voles from Asia and Africa.

Spatial tissue proteomics reveals distinct landscapes of heterogeneity in cutaneous papillomavirus-induced keratinocyte carcinomas.

Infection with certain cutaneous human papillomaviruses (HPV), in conjunction with chronic ultraviolet (UV) exposure, are the major cofactors of non-melanoma skin cancer (NMSC), the most frequent cancer type worldwide. Cutaneous squamous cell carcinomas (SCCs) as well as tumors in general represent three-dimensional entities determined by both temporal and spatial constraints. Whole tissue proteomics is a straightforward approach to understand tumorigenesis in better detail, but studies focusing on different progression states toward a dedifferentiated SCC phenotype on a spatial level are rare. Here, we applied an innovative proteomic workflow on formalin-fixed, paraffin-embedded (FFPE) epithelial tumors derived from the preclinical animal model Mastomys coucha. This rodent is naturally infected with its genuine cutaneous papillomavirus and closely mimics skin carcinogenesis in the context of cutaneous HPV infections in humans. We deciphered cellular networks by comparing diverse epithelial tissues with respect to their differentiation level and infection status. Our study reveals novel regulatory proteins and pathways associated with virus-induced tumor initiation and progression of SCCs. This approach provides the basis to better comprehend the multistep process of skin carcinogenesis.

Spiny mice (Acomys) cells fail to engraft in NOD scid gamma.

Immune cells and stromal cells regulate wound healing and regeneration through complex activation patterns with spatiotemporal variation. The scarless regeneration of Spiny mice (Acomys species) is no exception; differential activation of immune and stromal cell populations seems to play a role in its remarkable regenerative capacity. To elucidate the role and interplay of Acomys immune cells in mammalian regeneration, we sought to create Acomys-Mus chimeras by transplanting bone marrow (BM) from Acomys into NOD Scid Gamma (NSG), a severely immunodeficient mouse line often used in creating humanized mice. Here, we report that Acomys BM cells fail to reconstitute and differentiate when transferred to irradiated NSG adults and neonates. In addition, we did not detect the presence of donor cells nor observe the onset of Graft versus Host Disease (GvHD)-like pathology, even after transplanting Acomys splenocytes in Acomys-Mus chimeras suggesting early graft failure. Overall, these results demonstrate the adoptive transfer of Acomys BM alone is not sufficient to establish Acomys hematopoietic system in NSG mouse.

Response of wild rodents to red fox feces: implication for the echinococcus infection.

Echinococcus multilocularis causes zoonotic disease, alveolar echinococcosis. The life cycle of E. multilocularis is maintained by the predator-prey relationship between red foxes and rodents. Infection to red fox (Vulpes vulpes) of E. multilocularis is considered that rodents take eggs of E. multilocularis, then red fox forage the rodents. However, it has been not known how to take eggs by rodents. On infection process of E. multilocularis from red foxes to rodents, we predicted that rodents would forage or touch with feces of red fox to use undigested materials within the feces. We monitored rodent's response to fox feces and their distance to the feces by using camera trap from May to October 2020. Myodes spp. and Apodemus spp. touched fox feces, and touch rate of Apodemus spp. was significantly higher than that of Myodes spp. We found smelling and passing as contact behaviors to fox feces by Myodes spp., while Apodemus spp. showed behaviors which oral directly contacted feces. There was no significant difference on the shortest distance between Apodemus spp. and Myodes spp. The distance between 0 cm and 5 cm was mostly observed for both rodents. The results that Myodes spp. did not forage feces and their contact to feces was low frequency suggested that the infection from red foxes to Myodes spp., the main intermediate host, was to be other pathways. The approach to feces and the act near feces might increase the probability attached with eggs.

African Spiny Mice (Acomys) Exhibit Mild Osteoarthritis Following Meniscal Injury.

OBJECTIVE: Hyaline cartilage has limited innate healing abilities and hyaline cartilage loss is a hallmark of osteoarthritis (OA). Animal models can provide important insights into cartilage regeneration potential. One such animal model, the African spiny mouse (Acomys), is capable of regenerating skin, skeletal muscle, and elastic cartilage. This study aims to evaluate whether these regenerative abilities protect Acomys with meniscal injury from OA-related joint damage and behaviors indicative of joint pain and dysfunction. DESIGN: Acomys received destabilization of the medial meniscus (DMM) surgery (n = 11) or a skin incision (n = 10). Gait testing occurred at 4, 6, 8, 10, and 12 weeks after surgery. At endpoint, joints were processed for histology to assess cartilage damage. RESULTS: Following joint injury, Acomys with DMM surgery altered their walking patterns by increasing the percent stance time on the contralateral limb relative to the operated limb, thereby reducing the amount of time the injured limb must bear weight on its own throughout the gait cycle. Histological grading indicated evidence of OA-related joint damage in Acomys with DMM surgery; these changes were primarily driven by loss of structural integrity in the hyaline cartilage. CONCLUSIONS: Acomys developed gait compensations, and the hyaline cartilage in Acomys is not fully protected from OA-related joint damage following meniscal injury, although this damage was less severe than that historically found in C57BL/6 mice with an identical injury. Thus, Acomys do not appear to be completely protected from OA-related changes, despite the ability to regenerate other wounded tissues.

Pre-hyperglycemia immune cell trafficking underlies subclinical diabetic cataractogenesis.

BACKGROUND: This work elucidates the first cellular and molecular causes of cataractogenesis. Current paradigm presupposes elevated blood glucose as a prerequisite in diabetic cataractogenesis. Novel evidence in our model of diabetic cataract challenges this notion and introduces immune cell migration to the lens and epithelial-mesenchymal transformation (EMT) of lens epithelial cells (LECs) as underlying causes. METHODS: Paucity of suitable animal models has hampered mechanistic studies of diabetic cataract, as most studies were traditionally carried out in acutely induced hyperglycemic animals. We introduced diabetic cataract in the Nile grass rat (NGR) that spontaneously develops type 2 diabetes (T2D) and showed its closeness to the human condition. Specialized stereo microscopy with dual bright-field illumination revealed novel hyperreflective dot-like microlesions in the inner cortical regions of the lens. To study immune cell migration to the lens, we developed a unique in situ microscopy technique of the inner eye globe in combination with immunohistochemistry. RESULTS: Contrary to the existing paradigm, in about half of the animals, the newly introduced hyper reflective dot-like microlesions preceded hyperglycemia. Even though the animals were normoglycemic, we found significant changes in their oral glucose tolerance test (OGTT), indicative of the prediabetic stage. The microlesions were accompanied with significant immune cell migration from the ciliary bodies to the lens, as revealed in our novel in situ microscopy technique. Immune cells adhered to the lens surface, some traversed the lens capsule, and colocalized with apoptotic nuclei of the lens epithelial cells (LECs). Extracellular degradations, amorphous material accumulations, and changes in E-cadherin expressions showed epithelial-mesenchymal transformation (EMT) in LECs. Subsequently, lens fiber disintegration and cataract progression extended into cortical, posterior, and anterior subcapsular cataracts. CONCLUSIONS: Our results establish a novel role for immune cells in LEC transformation and death. The fact that cataract formation precedes hyperglycemia challenges the prevailing paradigm that glucose initiates or is necessary for initiation of the pathogenesis. Novel evidence shows that molecular and cellular complications of diabetes start during the prediabetic state. These results have foreseeable ramifications for early diagnosis, prevention and development of new treatment strategies in patients with diabetes.

Daytime Light Deficiency Leads to Sex- and Brain Region-Specific Neuroinflammatory Responses in a Diurnal Rodent.

Seasonal changes in peripheral inflammation are well documented in both humans and animal models, but seasonal changes in neuroinflammation, especially the impact of seasonal lighting environment on neuroinflammation remain unclear. To address this question, the present study examined the effects of environmental lighting conditions on neuroinflammation in a diurnal rodent model, Nile grass rats (Arvicanthis niloticus). Male and female grass rats were housed in either bright (brLD) or dim (dimLD) light during the day to simulate a summer or winter light condition, respectively. After 4 weeks, microglia markers Iba-1 and CD11b, as well as pro-inflammatory cytokines TNF-α and IL-6, were examined in the anterior cingulate cortex (ACC), basolateral amygdala (BLA), and dorsal hippocampus (dHipp). The results revealed that winter-like dim light during the day leads to indicators of increased neuroinflammation in a brain site- and sex-specific manner. Specifically, relatively few changes in the neuroinflammatory markers were observed in the ACC, while numerous changes were found in the BLA and dHipp. In the BLA, winter-like dimLD resulted in hyper-ramified microglia morphology and increased expression of the pro-inflammatory cytokine IL-6, but only in males. In the dHipp, dimLD led to a higher number and hyper-ramified morphology of microglia as well as increased expression of CD11b and TNF-α, but only in females. Neuroinflammatory state is thus influenced by environmental light, differently in males and females, and could play a role in sex differences in the prevalence and symptoms of psychiatric or neurological disorders that are influenced by season or other environmental light conditions. Diurnal Nile grass rats were housed under bright or dim light during the day for 4 weeks, simulating seasonal fluctuations in daytime lighting environment. Dim light housing resulted in hyper-ramified morphology of microglia (scale bar, 15 µm) and altered expression of pro-inflammatory cytokines (TNF-α) in a sex- and brain region-specific manner.

A Nile rat transcriptomic landscape across 22 organs by ultra-deep sequencing and comparative RNA-seq pipeline (CRSP).

RNA sequencing (RNA-seq) has been a widely used high-throughput method to characterize transcriptomic dynamics spatiotemporally. However, RNA-seq data analysis pipelines typically depend on either a sequenced genome and/or corresponding reference transcripts. This limitation is a challenge for species lacking sequenced genomes and corresponding reference transcripts. The Nile rat (Arvicanthis niloticus) has two key features - it is daytime active, and it is prone to diet-induced diabetes, which makes it more similar to humans than regular laboratory rodents. However, at the time of this study, neither a Nile rat genome nor a reference transcript set were available, making it technically challenging to perform large-scale RNA-seq based transcriptomic studies. This genome-independent work progressed concurrently with our generation of a Nile rat genome. A well-annotated genome requires several iterations of manually reviewing curated transcripts and takes years to achieve. Here, we developed a Comparative RNA-Seq Pipeline (CRSP), integrating a comparative species strategy independent of a specific sequenced genome or species-matched reference transcripts. We performed benchmarking to validate that our CRSP tool can accurately quantify gene expression levels. In this study, we generated the first ultra-deep (2.3 billion × 2 paired-end) Nile rat RNA-seq data from 59 biopsy samples representing 22 major organs, providing a unique resource and spatial gene expression reference for Nile rat researchers. Importantly, CRSP is not limited to the Nile rat species and can be applied to any species without prior genomic knowledge. To facilitate a general use of CRSP, we also characterized the number of RNA-seq reads required for accurate estimation via simulation studies. CRSP and documents are available at: https://github.com/pjiang1105/CRSP.

Interpretation of gut microbiota data in the 'eye of the beholder': A commentary and re-evaluation of data from 'Impacts of radiation exposure on the bacterial and fungal microbiome of small mammals in the Chernobyl Exclusion Zone'.

Evidence that exposure to environmental pollutants can alter the gut microbiota composition of wildlife includes studies of rodents exposed to radionuclides. Antwis et al. (2021) used amplicon sequencing to characterise the gut microbiota of four species of rodent (Myodes glareolus, Apodemus agrarius, A. flavicollis and A. sylvaticus) inhabiting the Chernobyl Exclusion Zone (CEZ) to examine possible changes in gut bacteria (microbiota) and gut fungi (mycobiota) associated with exposure to radionuclides and whether the sample type (from caecum or faeces) affected the analysis. The conclusions derived from the analyses of gut mycobiota are based on data that represent a mixture of ingested fungi (e.g. edible macrofungi, polypores, lichens and ectomycorrhizae) and gut mycobiota (e.g. microfungi and yeasts), which mask the patterns of inter- and intraspecific variation in the authentic gut mycobiota. Implying that 'faecal samples are not an accurate indicator of gut composition' creates an unnecessary controversy about faecal sampling because the comparison of samples from the caecum and faeces confounds many other possible drivers (including different animals from different locations, sampled in different years) of variation in gut microbiota. It is relevant also that Antwis et al.'s (2021) data lack statistical power to detect an effect of exposure to radionuclides on the gut microbiota because (1) all of their samples of Apodemus mice had experienced a medium or high total absorbed dose rate and (2) they did not collect samples of bank voles (M. glareolus) from replicate contaminated and uncontaminated locations. Discussion of Antwis et al.'s (2021) analysis, especially the claims presented in the Abstract, is important to prevent controversy about the outcome of research on the biological impacts of wildlife inhabiting the CEZ.

Discovery of novel DNA viruses in small mammals from Kenya.

Emergence and re-emergence of infectious diseases of wildlife origin have led pre-emptive pathogen surveillances in animals to be a public health priority. Rodents and shrews are among the most numerically abundant vertebrate taxa and are known as natural hosts of important zoonotic viruses. Many surveillance programs focused more on RNA viruses. In comparison, much less is known about DNA viruses harbored by these small mammals. To fill this knowledge gap, tissue specimens of 232 animals including 226 rodents, five shrews and one hedgehog were collected from 5 counties in Kenya and tested for the presence of DNA viruses belonging to 7 viral families by PCR. Diverse DNA sequences of adenoviruses, adeno-associated viruses, herpesviruses and polyomaviruses were detected. Phylogenetic analyses revealed that most of these viruses showed distinction from previously described viruses and formed new clusters. Furthermore, this is the first report of the discovery and full-length genome characterization of a polyomavirus in Lemniscomys species. This novel polyomavirus, named LsPyV KY187, has less than 60% amino acid sequence identity to the most related Glis glis polyomavirus 1 and Sciurus carolinensis polyomavirus 1 in both large and small T-antigen proteins and thus can be putatively allocated to a novel species within Betapolyomavirus. Our findings help us better understand the genetic diversity of DNA viruses in rodent and shrew populations in Kenya and provide new insights into the evolution of those DNA viruses in their small mammal reservoirs. It demonstrates the necessity of ongoing pathogen discovery studies targeting rodent-borne viruses in East Africa.

Coronal brain atlas in stereotaxic coordinates of the African spiny mouse, Acomys cahirinus.

The African spiny mouse (Acomys cahirinus) is an emerging model of mammalian epimorphic regeneration that has aroused the interest of the scientific community in the last decade. To date, studies on brain repair have been hindered by the lack of knowledge on the neuroanatomy of this species. Here, we present a coronal brain atlas in stereotaxic coordinates, which allows for three-dimensional identification and localization of the brain structures of this species. The brain of 12-week-old spiny mice was mapped in stereotaxic coordinates using cresyl violet-stained brain sections obtained from coronal cryosectioning of the brain after transcardial perfusion with fixative. The atlas is presented in 42 plates representing sections spaced 240 µm apart. Stereotaxic coordinates were validated using both a model of Parkinsonian lesion of the striatum with 6-hydroxydopamine and labeling of the corticospinal tract in the spiny mouse spinal cord using AAV1/2-GFP intracortical injections. This work presents a new tool in A. cahirinus neurobiology and opens new avenues of research for the investigation of the regenerative ability of A. cahirinus in models of brain disorders.

Environmental radiation on large Japanese field mice in Fukushima reduced colony forming potential in hematopoietic progenitor cells without inducing genomic instability.

PURPOSE: To study the environmental radiation effects of wild animals after the Fukushima Dai-ichi nuclear power plant accident, we assessed effects on hematopoietic progenitor cells (HPCs) in large Japanese field mice (Apodemus speciosus). MATERIALS AND METHODS: A. speciosus were collected from three contaminated sites and control area. The air dose-rates at the control and contaminated areas were 0.96 ± 0.05 µGy/d (Hirosaki), 14.4 ± 2.4 µGy/d (Tanashio), 208.8 ± 31.2 µGy/d (Ide), 470.4 ± 93.6 µGy/d (Omaru), respectively. We investigated possible DNA damage and pro-inflammatory markers in the bone marrow (BM) cells. The colony-forming potential of BM cells was estimated by the number of HPC colony-forming cells. Radiation-induced genomic instability (RIGI) in HPCs was also analyzed by quantifying delayed DNA damage in CFU-GM clones. RESULTS: Although no significant differences in DNA damage and inflammation markers in BM cells from control and contaminated areas, the number of HPC colonies exhibited an inverse correlation with air dose-rate. With regard to RIGI, no significant differences in DNA damage of CFU-GM clones between the mice from the control and the three contaminated areas. CONCLUSIONS: Our study suggests that low dose-rate radiation of more than 200 Gy/d reduced HPCs, possibly eliminating genomically unstable HPCs.

Proteomic Biomarker Analysis of Serum from Japanese Field Mice (Apodemus Speciosus) Collected within the Fukushima Difficult-to-return Zone.

ABSTRACT: The environmental impact of the Fukushima Daiichi nuclear power plant accident is a source of ongoing concern as there is uncertainty regarding the effects of chronic radiation exposure on local plant and animal life from Fukushima-derived radionuclides. In the current study, changes in proteomic biomarker expression due to chronic environmentally-derived radiation exposures was examined in wild field mice. Serum from 10 wild field mice (Apodemus speciosus) native to the Fukushima difficult-to-return zone and from eight wild field mice native to the Soma area (control) were collected. External dose estimations were completed using measurements of ambient radiation levels and calculating 137Cs concentrations in soil. Internal dose was estimated by counting whole mice using an HPGe detector. Age of the mice was estimated using molar wear. Serum was screened using the aptamer-based SOMAscan proteomic assay technology for changes in expression of 1,310 protein analytes. A subset panel of protein biomarkers that demonstrated significant changes in expression between control and exposed mice was determined and analyzed using Ingenuity Pathway Analysis (IPA). Control animals had a calculated lifetime dose range from 0.001 to 0.007 Gy, and exposed animals had a calculated lifetime dose range from 0.01 to 0.64 Gy. No discernable effect of dose rate was seen as relative dose rate correlated with dose for all samples. Detectable values were obtained for all 1,310 proteins included in the SOMAscan assay. Subset panels of proteins demonstrating significant (p < 0.05) changes in expression with either an upregulated or downregulated 1.5-fold change over control were identified for both the sample cohort inclusive of all exposed samples and the sample cohort restricted to samples from animals receiving "low" dose exposures. These panels of proteins from exposed animals were analyzed using IPA, which highlighted changes in key biological pathways related to injury, respiratory, renal, urological, and gastrointestinal disease, and cancer. Significant changes in expression of proteomic biomarkers were seen in the serum of wild field mice that received environmental exposure to Fukushima-derived radionuclides. Our findings demonstrate novel biomarkers of radiation exposure in wildlife within the Fukushima difficult-to-return zone.

Environmental exposure to cadmium reduces the primary antibody-mediated response of wood mice (Apodemus sylvaticus) from differentially polluted locations in the Netherlands.

The Wood mouse (Apodemus sylvaticus) is a widespread mammalian species that acts as a reservoir host for multiple infections, including zoonotic diseases. Exposure to immunotoxins, like for instance trace metals, may reduce the ability of the host to mount proper responses to pathogens, potentially increasing the transmission and prevalence of infections. Antibody-mediated responses are crucial in preventing and limiting infections, and the quantification of the primary antibody response is considered a sensitive predictor of immunosuppression. The current study aims to investigate effects of cadmium exposure on the antibody-mediated responses of wood mice inhabiting polluted and non-polluted areas in the Netherlands. Wood mice were captured alive at different locations and immunized to sheep red blood cells (SRBC) to induce a primary antibody response. SRBC-specific antibody-producing cells, or plaque forming cells (PFC), were quantified and related to kidney cadmium levels. Differential circulating main leukocyte populations were also characterised. Cadmium concentrations in mice kidneys differed between mice captured at different locations, and increased with individual body mass, likely associated with age-related time of exposure. Effect of cadmium was apparent on the percentages of B cell counts in blood. Because of potential natural immune heterogeneity between wild rodent populations, mice immune responses were analysed and compared grouped by captured locations. Capture location had significant effect on the total counts of white blood cells. Increasing cadmium exposure in wood mice captured from polluted sites was associated with a decrease of splenic PFC counts. This field research shows that wood mice antibody responses can be impaired by cadmium exposure, even at low environmental levels, by affecting B cell functioning mainly. Impaired B cell function can make exposed mice more susceptible to infections, potentially increasing the reservoir function of their populations. It also shows that immunomodulatory effects in the field should be assessed site specifically.