Search Results (149)

Background/Objectives: Depression is frequently comorbid with obesity. We previously showed that astrocyte-mediated hyperactive ventral hippocampal glutamatergic afferents to the nucleus accumbens determined the exhibition of depression-like behaviors in obese murine models. However, it remains unclear if the metabolic disorder-induced depressive phenotypes and astrocytic maladaptation in the ventral hippocampus (vHPC) could be reversed following the amelioration of key metabolic impairments such as insulin resistance and dyslipidemia. Method: Male mice were fed a high-fat diet (HFD) for 12 weeks, followed by either continued HFD feeding (HFD/HFD group) or a switch to a standard diet for 4 weeks (HFD/SD group). Results: Results showed that HFD/HFD mice displayed not only glucose/lipid metabolic dysfunction, but also depression-like behaviors. In contrast, HFD/SD mice showed improvements in metabolic disorders and depressive phenotypes. Mechanistically, dietary fat reduction restored astrocyte morphology and glutamate transporter expression (GLT-1, GLAST) in the vHPC and suppressed neuroinflammatory signaling, as evidenced by reduced levels of phospho-IKK, TNF-α, IL-1β, and IL-6 in the vHPC. Conclusions: These findings suggest that dietary fat reduction reverses obesity-induced depressive phenotypes, astrocytic deficits, at least in part via suppression of neuroinflammation through the NF-κB signaling pathway. Full article

In recent years, there has been a growing interest in the frictional anisotropy of snake scale-inspired surfaces, especially its potential applications in enhancing the bearing capacity of foundations (piles, anchor elements, and suction caissons) and reducing materials consumption and installation energy. This study first investigated the frictional properties and surface morphologies of the ventral scales of Cantor’s rat snakes (Ptyas dhumnades). Based on the findings on the snake scales, a novel snakeskin-inspired geosynthetic reinforcement (SIGR) is developed using 3D-printed polylactic acid (PLA). A series of pullout tests under different normal loads (25 kPa, 50 kPa, and 75 kPa) were performed to analyze the pullout behavior of SIGR in sandy soil. Soil deformation and shear band thickness were measured using Particle Image Velocimetry (PIV). The results revealed that the ventral scales of Ptyas dhumnades have distinct thorn-like micro-protrusions pointing towards the tail, which exhibit frictional anisotropy. A SIGR with a unilateral (one-sided) layout scales (each scale 1 mm in height and 12 mm in length) could increase the peak pullout force relative to a smooth-surface reinforcement by 29% to 67%. Moreover, the peak pullout force in the cranial direction (soil moving against the scales) was found to be 13% to 20% greater than that in the caudal direction (soil moving along the scales). The pullout resistance, cohesion, and friction angle of SIGR all showed significant anisotropy. The soil deformation around the SIGR during pullout was more pronounced than that observed with smooth-surface reinforcement, which suggests that SIGR can mobilize a larger volume of soil to resist external loads. This study demonstrates that SIGR is able to enhance the pullout resistance of reinforcements, thereby improving the stability of reinforced soil structures, reducing materials and energy consumption, and is important for the sustainability of geotechnical engineering. Full article

We describe a new genus and species of the tribe Ichthyomyini (Rodentia: Sigmodontinae) based on three specimens collected in Machupicchu, Cusco, in the southern Peruvian Andes. Our study includes a comprehensive morphological analysis of 201 specimens representing all recognized species, employing multivariate statistics (principal component analysis) of external and cranial measurements, as well as phylogenetic methods. We used maximum parsimony for morphological data and concatenated molecular datasets (Cytochrome b [17 species], IRBP [15 species], and RAG1 [11 species]) analyzed via maximum likelihood and Bayesian inference. The new genus and species exhibit an allopatric distribution relative to other Ichthyomyini and are distinguished by the following combination of traits: dull slate-gray dorsal fur, lighter ventrally without contrast to the dorsum; incomplete philtrum; vestigial pinna concealed within head fur; long, broad hindfeet with a well-developed fringe of stiff hairs and brown soles; laterally compressed tail exceeding head-body length; type 1 carotid circulation pattern; absence of the orbicular apophysis of the malleus; presence of posteroloph and posterolophid in M1, M2, m1, and m2; unilocular hemiglandular stomach (non-reduced). Full article

We evaluated the global distribution of Anolis sagrei based on bibliographic records, GBIF, and iNaturalist data. Native to Cuba and the Bahamas, this lizard has spread across mainland America, particularly in the Caribbean, Central America, and parts of the U.S. It has also been introduced in Asia, and according to iNaturalist observations, it has been recorded in Israel, Canada, and northern South America. This species is especially abundant in the Caribbean and southeastern U.S., with high concentrations of records indicating a significant range expansion. In Ecuador, A. sagrei has been recorded along the coast and in the Amazon, with occurrences in Esmeraldas, Manabí, Guayas, Francisco de Orellana, and for the first time in Zamora Chinchipe (southern Amazon), specifically in El Pangui. The capture of 10 individuals confirmed their morphology, showing similarities with populations from Honduras and Cuba but differences in scalation and body size. In Ecuador, the fourth toe lamellae range from 29 to 33, consistent with those populations, while dorsal and ventral scales show variation (dorsal: 11–22, ventral: 10–25). Climate change favors its spread by enabling the colonization of new habitats. As an invasive species, it threatens local biodiversity, highlighting the need for monitoring and control in Amazonian Ecuador. An expanded abstract in Spanish is available, intended for local decision-makers. Full article

In this study, using scanning electron microscope (SEM) and optical microscopy, we give a detailed description of the Acanthoponera mucronata male, supplementing the former male-based genus diagnoses. In particular, we described for the first time the following characters: the morphology of the external genitalia, the peculiar antennal cleaning and the absence of the metapleural gland orifice. In addition, we show the pretarsal claws and the ventral excavation in the gaster that represent diagnostic male features of all Acanthoponera species, never imaged before. The use of modern taxonomic standards is particularly important in order to make these data available to future comparative analyses. Full article

We describe a new species of snake of the genus Tachymenoides using molecular and morphological evidence. The description is based on 21 specimens (4 females, 17 males) obtained in the regions of Pasco, Junín, and Puno between 2190 and 3050 m elevation. A maximum likelihood phylogenetic tree based on two mitochondrial (12S and cyt-b) genes and one nuclear (c-mos) gene shows that the new species is the sister taxon of T. affinis and distinct from Galvarinus tarmensis, which we transfer back to Tachymenis. The new species has smooth dorsal scales without apical pits usually in 19/17/15 series, 1 preocular, 2 postoculars, 1 loreal undivided nasal scale, 8 supralabials (4th and 5th in contact with the eye), 9 infralabials, 1–2+2–3 temporals, 139–157 ventrals, 52–67 subcaudals, and a divided cloacal scale. The longest specimen, a male, had a total length of 559 mm. Two females contained six and five eggs with small embryos. In life, the dorsum and flanks are olive brown to pale grayish brown with scattered black and cream flecks and no longitudinal stripes. Ventral coloration is highly variable, nearly uniformly black, mottled gray and dark-gray, mottled pale gray and tan, or pale grayish tan. Usually, three irregularly shaped, narrow, longitudinal ventral stripes are present. The iris is brown with a distinct yellowish-tan ringlet. Full article

Background/Objectives: Schizophrenia is a severe psychiatric disorder characterized by deficits in perception and advanced cognitive functions. Prior studies have reported abnormal lateralization in cortical morphology and functional connectivity in schizophrenia. However, it remains unclear whether schizophrenia affects hemispheric asymmetry in the hierarchical organization of functional connectome. Methods: Here, we apply a gradient mapping framework to the hemispheric functional connectome to estimate the first three gradients, which characterize unimodal-to-transmodal, visual-to-somatomotor, and somatomotor/default mode-to-multiple demand hierarchy axes. We then assess between-group differences in intra- and inter-hemispheric asymmetries of these three functional gradients. Results: We find that, compared to healthy controls, patients with schizophrenia exhibit significantly altered hemispheric asymmetry in functional gradient across multiple networks, including the dorsal attention, ventral attention, visual, and control networks. Region-level analyses further reveal that patients with schizophrenia show significantly abnormal hemispheric gradient asymmetries in several cortical regions in the dorsal prefrontal gyrus, medial superior frontal gyrus, and somatomotor areas. Lastly, we find that hemispheric asymmetries in functional gradients can differentiate between patients and healthy controls and predict the severity of positive symptoms in schizophrenia. Conclusions: Collectively, these findings suggest that schizophrenia is associated with altered hemispheric asymmetry in functional hierarchy, providing novel perspectives for understanding the atypical brain lateralization in schizophrenia. Full article

New ornithopod remains have recently been discovered at the Vadillos-1 paleontological site, in Cuenca Province, Central Spain. These remains were collected in sandy and clayey deposits within “Wealden” alluvial facies, which correspond to an upper Barremian (Lower Cretaceous) alluvial-palustrine muddy floodplain paleoenvironment. The remains correspond to a part of a sacrum, including three fused sacral vertebral centra with sacral ribs and part of the sacral yoke, together with an isolated unfused sacral vertebra. An incomplete ischium has also been identified, likely belonging to the same individual. The sacral block exhibits a broad sulcus that begins at the most anterior sacral vertebra, continues through the middle vertebra, and ends in the area where the middle and the most posterior vertebrae are fused. The non fused sacral vertebra also displays a ventral sulcus. The incomplete ischium has a curved shaft with a triangular cross section towards the distal end. The combination of the morphological features of the sacrum and ischium allow its attribution to Iguanodon cf. bernissartensis. This species is identified in the area for the first time, adding new valuable data about the dinosaur assemblages from the Lower Cretaceous of Spain. Full article

Ophidiomyces ophidiicola, the fungus causing Snake Fungal Disease (SFD) or ophidiomycosis, is prevalent in North American snakes and can have deleterious population effects. Northern pine snakes (Pituophis melanoleucus melanoleucus) in New Jersey often test positive for ophidiomycosis. In this paper, we use qPCR to examine changes in prevalence from 2018 to 2023, and differences by age, sex, and morphological sampling locations. We swabbed ventral surfaces, head, and cloaca of snakes, and lesions and eyes if there were clinical ophidiomycosis signs. A snake was considered positive if any site was positive by qPCR. The prevalence was 47% (2018), increased to 100% (2022), but declined to 46% in 2023. The prevalence was highest in snakes with lesions (46–100%); head swabs had the lowest rates. The more lesions a snake had, the more likely it was that at least one would be positive. Males had significantly more lesions than females, but the prevalence was similar. In 2023, the prevalence of O. ophidiicola was low, but the prevalence of lesions did not decrease as markedly. We discuss the temporal changes in the positivity for O. ophidiicola and its implications for ophidiomycosis effects, suggesting that the fungus is endemic in this population. Full article

Epipactis helleborine (L.) Crantz is considered a challenging and phenotypically difficult species to identify due to its wide range of morphological variability. This variability is mainly observed in the perianth parts but also extends to the gynostemium structure, which has so far been considered one of the most useful diagnostic characteristics. As a result, a simple graphic illustrating the structural pattern of gynostemium morphology has appeared in 10 different forms in available European taxonomic keys, which significantly complicates the identification of this species. A total of 122 flowers of E. helleborine were collected from four natural populations in the Lower Silesia region (Poland) between 2017 and 2019 and analysed for gynostemium morphological variation. Geometric morphometric analyses, including Procrustes ANOVA, PCA, and CVA, were used to examine gynostemium shape, with statistical tests assessing variation in size and stigma inclination angle among populations, individual plants (ramets), and years of research. Statistical analysis revealed significant positive correlations between gynostemium width and height, with significant variation in size and angle of stigma inclination, primarily driven by population, while ramet and year of research had a lesser impact. Geometric morphometric analyses indicated significant population-level variation in gynostemium shape, with principal component analysis identifying the ventral view as the most informative for discriminating these differences. The first two principal components explained the major shape variation, and canonical variate analysis confirmed that this view is most important for species identification. Full article

Sex differences in the neurobiology of responses to chronic stress have been widely discussed but remain poorly understood. We found that chronic unpredictable mild stress (CUMS) experienced during adolescence induced different behavioral patterns in adult males and females. Immunohistochemical analysis of the CA1 field of the dorsal and ventral hippocampus revealed no quantitative or morphological changes in astrocytes in the long term after CUMS. Real-time PCR analysis showed no increase in the expression level of SigmaR1 after CUMS relative to individual housekeeping genes. Analysis of mouse cerebral cortex homogenates showed that IL-1β levels only decreased after CUMS in males. However, the SigmaR1 levels were significantly higher in the CUMS groups than in the control groups in both sexes. It can be concluded that biological sex and age influence the response to CUMS, although not in all cases. Further studies are needed to understand the effects of chronic stress on males and females. This is important because men and women have different risks for stress and mental disorders. Full article

The genus Scincella Mittleman, 1950, belonging to the family Scincidae, exhibits considerable morphological convergence, complicating species delimitation and resulting in underestimated diversity. Currently, 41 species are formally recognized in this genus, although this figure likely underestimates its true richness. In this study, a new species of the genus Scincella, Scincella chengduensis sp. nov., is described from urban and suburban areas of Chengdu, Sichuan Province, Southwest China. Morphological features and phylogenetic analyses confirmed that the new species is distinct from all previously recognized congeners. The new species can be clearly distinguished by a combination of the following unique characters: (1) slender, medium-sized body, snout-vent length 28.4–43.2 mm; (2) infralabials seven, rarely six; (3) supraciliaries six or seven; (4) tympanum deeply recessed without lobules, tympanum diameters equal to or exceeding palpebral disc diameters; (5) midbody scale-row counts 23; (6) dorsal scales smooth, slightly enlarged, paravertebral scale-row counts 57–60, ventral scale-row counts 42–44, gulars 21–22; (7) upper edge of lateral longitudinal stripes relatively straight, four rows of dorsal scales in middle; (8) enlarged, undivided lamellae beneath finger IV 8–9, enlarged, undivided lamellae beneath toe IV 10–12; (9) ventral surface densely covered with dark spots; (10) grayish-brown, irregular dorsal stripes 2–3, black dorsolateral stripes from posterior corner of eye to lateral side of tail. This discovery underscores the underestimated diversity of Scincella in China and highlights the importance of urban habitats as reservoirs of hidden biodiversity. A diagnostic key to the Scincella species of China is also provided. Full article

A new species of Collembola in the genus Coecobrya, C. microphthalma sp. nov., is described from a cave environment in Saraburi province, central Thailand. The new species is the second described species of the boneti-group found in the country. It is most similar to C. chompon Nilsai, Lima & Jantarit, 2022, which is also described from a Thai cave. However, the new species is morphologically different from C. chompon in having orange dot pigmentation on its body and a combination of other morphological characteristics such as the number of sublobal hairs on the maxillary outer lobe and the number of medio-sublateral mac on Th. II, Abd. I, Abd. III and Abd. IV and the anterior face of the ventral tube. The morphological comparison of all known boneti species and a key to the world species of Coecobrya of the boneti-group are given. Coecobrya microphthalma sp. nov. was successfully cultured in the laboratory. The thermal tolerance of the new species was studied and tested with seven different temperature experiments (27 °C as a control, 30, 32, 33, 34, 35 and 36 °C). The results showed that C. microphthalma sp. nov. cannot survive at a temperature higher than 32 °C after exposure to the experimental heat for 7 and 14 consecutive days. At 27, 30 and 32 °C, C. microphthalma sp. nov. remained alive and produced eggs, but the duration of egg production and number of egg-laying days significantly declined when the temperature increased (p < 0.001). An interesting aspect of their reproduction concerns temperature. At 32 °C (5 °C above the control temperature), the F1 generation survived, was active and was able to molt to the adult stage. However, specimens were unable to produce the next generation of offspring. For postembryonic development, C. microphthalma sp. nov. required six molts to reach the adult stage. The development rate (from egg to adult) varied and differed significantly between the tested temperatures (p < 0.001). An increase in temperature from the control temperature significantly accelerated the developmental rate from egg to juvenile instars to adult with a statistical significance (p < 0.01). This study is the first attempt that provide information on the impact of increasing temperature on the population dynamics, reproductive capacity and life history of a subterranean tropical Collembola. Full article

We report the discovery of a novel free-living marine nematode, Dracognomus elongatus sp. nov., from the genus Dracognomus Allen & Noffsinger, 1978 (Nematoda: Draconematidae), collected from geniculate coralline algal assemblages in the intertidal zone along the eastern coast of Korea in the Northwest Pacific Ocean. Dracognomus elongatus sp. nov. is distinguished from its congeners by several key features: a relatively long body length (522 µm), densely developed minute spine-like ornamentation along the margins of body annules, small pore-shaped amphids (2 µm) with membranous tubes filled with corpus gelatum extending to the fifth body annule, twelve modified cephalic adhesion tubes located posterior to the rostrum, eight pairs of modified adhesion tubes in the mid-body region, an arrangement of both normal and modified subventral adhesion tubes (three pairs of each), disc-shaped tips on sublateral adhesion tubes, absence of copulatory thorns in males, and the presence of three pairs of short setae with no protuberances on the non-annulated tail end. Morphological details and illustrations were obtained using differential interference contrast microscopy. We also provide information on the geographic distribution and comparative characteristics of species within the genus Dracognomus, along with a schematic ventral view of a congener illustrating the arrangement of posterior adhesion tubes and copulatory thorns. Additionally, we present a species-level pictorial dichotomous key. Dracognomus elongatus sp. nov. is the eighth described species of this rare genus and marks the first record of Dracognomus in the Northwest Pacific Ocean. Full article

The aim of this preliminary study was to morphologically and dimensionally characterize the cat’s olfactory bulb in the sagittal plane and to establish potential relationships with the cranial conformation, based on the study of in vivo MRI images. Midsagittal and transverse T2-weighted images of the head of 40 cats subjected to MRI were selected. For each animal, the skull index was calculated to classify the cranial conformation. Then, for the olfactory bulb, the angle was calculated, the orientation was determined, and the sagittal section area was measured. It was established that animals classified as brachycephalic have more compact olfactory bulbs, with smaller cross-sectional areas, ventral orientation and smaller angles established with the line that goes from the hard palate and the intercondylar notch of the foramen magnum. Animals classified as dolichocephalic have more globose and wider olfactory bulbs, dorsal orientation, and larger angles. Mesocephalic animals present an intermediate position. Males and younger adult animals have olfactory bulbs with larger cross-sectional areas than females and older animals. This work allows for the preliminarily characterization of the olfactory bulb in cats in the sagittal plane, and the correlations identified with other head structures open doors for the use of the bulb as an early indicator for the establishment of alterations of varied etiology. Full article