Zoological Research最新文献

The collision of the Indian and Eurasian plates during the Eocene represents a major tectonic shift that significantly altered biotic dynamics and promoted species diversification across the Oriental region. To explain the diversification of taxa from the Indian subcontinent into Southeast Asia, two principal hypotheses have been proposed: the "Biotic-ferry" and "Step-stone" models. The subfamily Perittopinae, a lineage of semi-aquatic bugs comprising a single genus and 20 extant species, provides an ideal system for testing these hypotheses due to its disjunct distribution spanning the Indian subcontinent and Southeast Asia. This study conducted a comprehensive taxonomic analysis of the entire subfamily, incorporating newly defined morphological characters and multilocus phylogenetic analyses to reconstruct evolutionary relationships and historical biogeography. Morphological and phylogenetic evidence confirmed the monophyly of Perittopinae and supported the establishment of three new genera- Indoperittopus gen. nov., Pachyperittopus gen. nov., and Falciperittopus gen. nov.-in addition to four new species and four new combinations. Biogeographic reconstructions indicated a southern Indian origin, with initial diversification potentially occurring during the mid-Paleocene, coinciding with the major phases of the India-Eurasia collision. Subsequent range expansion over marine barriers facilitated colonization of the northern Sunda Shelf, consistent with the "Step-stone" dispersal mechanism. Later northward expansion from the southern Sunda Shelf during the early Miocene triggered further diversification of the genus Perittopus within the Indo-China Peninsula. These findings advance understanding of Perittopinae systematics, phylogeny, and historical biogeography, identifying the northward drift of the Indian plate and its eventual collision with Eurasia as catalysts of diversification within this semi-aquatic lineage.

Apoptosis preserves organismal homeostasis by selectively eliminating unnecessary or damaged cells, with accumulating evidence also suggesting that it activates regenerative pathways and facilitates tissue remodeling. To date, however, the regulatory mechanisms linking this form of programmed cell death to regeneration remain poorly defined, particularly in evolutionarily basal organisms. Using the sea cucumber ( Apostichopus japonicus) as a model for intestinal regeneration, this study identified robust apoptotic activity across key regenerative stages. Pharmacological suppression of apoptosis during wound healing and mesenteric scaffold formation critically impaired intestinal regeneration. Quantitative proteomics using direct data-independent acquisition (DIA) revealed coordinated down-regulation of lipid metabolic pathways under apoptosis-inhibited conditions, with notable suppression of Ca ^{2 +}-independent phospholipase A2 (iPLA2), an enzyme typically up-regulated during successful regeneration. In parallel, expression of regeneration-associated factors WNT6 and EGFL7 was markedly reduced under apoptotic blockade. Targeted inhibition of iPLA2, EGFL7, or WNT6 each resulted in impaired mesenteric outgrowth and reduced proliferative activity within the regenerating intestinal primordia. Collectively, these findings suggest two potential mechanistic pathways: apoptosis-mediated regeneration of lipid metabolism via iPLA2 and apoptosis-dependent activation of WNT6/EGFL7 signaling. This study provides mechanistic insight into apoptosis-coupled regenerative processes in basal deuterostomes and expands the conceptual framework of programmed cell death in tissue renewal.

Bivalve mollusks represent a taxonomically and economically significant clade within Mollusca. However, the regulatory mechanisms governing their embryonic development remain poorly characterized. The dwarf surf clam ( Mulinia lateralis), characterized by a short generation time and high fecundity, has recently gained recognition as an ideal model system for bivalve embryological research. This study explored the epigenetic mechanisms driving embryogenesis in M. lateralis, with a particular focus on the maternal-to-zygotic transition (MZT), by integrating chromatin-state profiling and transcriptomic analysis. For the first time in this species, CUT&Tag was employed to generate high-resolution landscapes of histone modifications H3K4me1, H3K4me3, H3K27me3, and H3K27ac across key developmental stages. The resulting data revealed extensive reprogramming of histone marks, indicating dynamic shifts in chromatin architecture during early embryonic development. Integration with transcriptomic data identified the timing of MZT in M. lateralis between the morula and gastrula stages and highlighted a suite of candidate genes essential for embryogenesis. These findings provide mechanistic insight into chromatin-mediated control of bivalve embryogenesis and establish M. lateralis as a robust platform for epigenomic research in marine invertebrates, with implications for functional gene studies and aquaculture advancement.

Major depressive disorder (MDD) is a debilitating psychiatric condition associated with substantial personal, societal, and economic costs. Despite considerable advances in research, most conventional antidepressant therapies fail to achieve adequate response in a significant proportion of patients, underscoring the need for novel, mechanism-based interventions. Lycium barbarum glycopeptide (LbGp), a bioactive compound with emerging neuroprotective properties, has been proposed as a candidate for antidepressant development; however, its therapeutic efficacy and underlying mechanisms remain largely uncharacterized. In this study, ventral forebrain organoids were generated from patients with MDD to investigate disease-related neurophysiological abnormalities. These organoids exhibited disrupted neuronal morphology, diminished calcium signaling, and impaired electrophysiological activity. Administration of LbGp effectively restored structural and functional deficits in MDD-derived organoids. Transcriptomic profiling revealed that LbGp ameliorated endoplasmic reticulum (ER) stress responses. To investigate the causative role of ER stress, control organoids were treated with the ER stress agonist CCT020312, which elicited neural activity impairments resembling those observed in MDD organoids. Notably, LbGp reversed the phenotypic consequences of CCT020312 exposure in control organoids. In conclusion, ventral forebrain organoids derived from individuals with MDD demonstrated that LbGp ameliorates disease-associated phenotypes by modulating ER stress.

Recent advances have deepened our understanding of the evolutionary and developmental origins of feather branching architectures. However, the internal tissue differentiation within these branches has received limited attention. This study examined eight fossilized feathers preserved in early Late Cretaceous Burmese amber, characterized by barb rami composed entirely of cortical tissue with no internal medulla. Based on barb rami morphology, the feathers were categorized into three distinct morphotypes. Comparative analysis with feather development in extant chickens suggested minimal tissue differentiation in these early feathers. Functional simulations further revealed that modern barb rami configurations provide greater aerodynamic stability than medulla-free early feathers under most conditions, highlighting flexural stiffness as a key factor in the evolution of feather branches. The presence of medulla-free barb rami suggests that although the three-level hierarchical branching pattern characteristic of modern feathers had emerged by the Jurassic, tissue differentiation within feather branches remained developmentally unstable during the Late Cretaceous. This instability likely contributed to the structural variability of early feathers, enabling morphologies that no longer persist in modern birds.

Astrocytes are associated with varying brain size between rodents and primates. As a close evolutionary relative of primates, the tree shrew ( Tupaia belangeri) provides a valuable comparative model for investigating glial architecture. However, the anatomical distribution and morphological characteristics of astrocytes in the tree shrew brain remain poorly characterized. In this study, glial fibrillary acidic protein (GFAP) immunofluorescence was employed to systematically examine the spatial distribution and morphology of astrocytes in the whole brain of tree shrews. Notably, GFAP-immunoreactive (ir) astrocytes were detected throughout the telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon. Distinct laminar distribution was evident in regions such as the main olfactory bulb and hippocampus. Semi-quantitative comparisons revealed significant regional differences in astrocyte density between tree shrews and mice, encompassing the main olfactory bulb, accessory olfactory bulb, olfactory tubercle, cortex, hippocampus, cortical amygdaloid nucleus, hypothalamus, thalamus, superior colliculus, interpeduncular nucleus, median raphe nucleus, and parabrachial nucleus. Compared to mice, tree shrews exhibited higher astrocyte density with increased morphological complexity in the posterior hypothalamic nucleus, dorsomedial hypothalamic nucleus, ventromedial hypothalamic nucleus, and periaqueductal gray, but lower density with greater morphological complexity in the hippocampus and substantia nigra. In the paraventricular hypothalamic nucleus and lateral hypothalamic area, GFAP-ir astrocytes displayed comparable densities between tree shrews and mice but exhibited region-specific differences in morphological complexity. This study provides the first brain-wide mapping of GFAP-ir astrocytes in tree shrews, revealing marked interspecies differences in their distribution and morphology, and establishing a neuroanatomical framework for understanding astrocyte involvement in diverse physiological and behavioral functions.

The Chinese tree shrew (Tupaia belangeri chinensis) has gained prominence as a model organism due to its phylogenetic proximity to primates, offering distinct advantages over traditional rodent models in biomedical research. However, the neuroanatomy of this species remains insufficiently defined, limiting its utility in neurophysiological and neuropathological studies. In this study, immunofluorescence microscopy was employed to comprehensively map the distribution of three calcium-binding proteins, parvalbumin, calbindin D-28k, and calretinin, across the tree shrew cerebrum. Serial brain sections in sagittal, coronal, and horizontal planes from 12 individuals generated a dataset of 3 638 cellular-resolution images. This dataset, accessible via Science Data Bank (https://doi.org/10.57760/sciencedb.23471), provides detailed region- and laminar-selective distributions of calcium-binding proteins valuable for the cyto- and chemoarchitectural characterization of the tree shrew cerebrum. This resource will not only advance our understanding of brain organization and facilitate basic and translational neuroscience research in tree shrews but also enhance comparative and evolutionary analyses across species.

Adipose-derived mesenchymal stem cells (ADSCs) represent a readily accessible and important source of mesenchymal stem cells (MSCs) capable of multilineage differentiation. The Hippo signaling pathway effector YAP has emerged as a pivotal regulator of stem cell fate, yet the specific molecular mechanism by which it modulates lipogenic differentiation of ADSCs has not been clearly defined. In this study, goat ADSCs (gADSCs) isolated from Albas goats in Inner Mongolia were used to investigate the role of YAP1 in adipogenic differentiation. Overexpression of YAP1 significantly promoted the differentiation of ADSCs into adipocytes, an effect accompanied by up-regulation of LATS2 and activation of the negative feedback loop of the Hippo signaling pathway. Elevated LATS2 expression induced YAP phosphorylation, leading to reduced nuclear levels of YAP and TAZ and their subsequent accumulation in the cytoplasm. YAP1 overexpression up-regulated LATS2 expression, which, in turn, enhanced the adipogenic differentiation of ADSCs. This pro-adipogenic effect of YAP1 was dependent on LATS2 kinase activity. These findings indicate that overexpression of YAP1 promotes ADSC adipogenesis by inducing LATS2 expression and activating the Hippo pathway negative feedback loop. Elucidating the molecular role of YAP in ADSC lipogenic differentiation holds great significance for regulating stem cell fate, treating metabolic disorders, and promoting hair follicle growth.

Birch mice (family Sicistidae) are small dipodoid rodents distributed in regions surrounding the Qinghai-Xizang Plateau and extending across the Palearctic. In China, members of the genus Sicista are rarely recorded, and their systematics remain poorly resolved. As part of the Second Xizang Plateau Expedition by the Kunming Institute of Zoology, Chinese Academy of Sciences, systematic surveys conducted in southern Xizang and the western Tianshan Mountains yielded two previously unrecognized species. Two specimens from southern Xizang were found to occupy a deeply divergent phylogenetic position within Sicistidae. Morphological assessments and molecular phylogenetic analyses of both extant and fossil Sicistidae, along with total-evidence dating and ancestral distribution reconstruction, identified these specimens as representatives of an ancient extant lineage that diverged from Sicista approximately 20.38 million years ago. This lineage is designated as a new genus, defined by the new species Breviforamen shannanensis gen. et sp. nov. Furthermore, 11 specimens from the Tianshan Mountains are described as a second new species, Sicista brevicauda sp. nov., based on diagnostic morphological and genetic features. Ancestral distribution reconstructions, combined with fossil records, indicate an early Miocene origin for Sicistidae across a broad region spanning the "Gobi" Desert to parts of North America. Climatic deterioration and increasing desertification during the mid-Miocene likely drove southward dispersal of Breviforamen gen. nov. into southern Xizang prior to the complete formation of the Yarlung Zangbo River. Overall, these findings broaden current understanding of Sicistidae diversity, elucidate the origin and dispersal patterns of the family, and highlight the presence of an ancient relict lineage in China.

Extreme heat and chronic water scarcity present formidable challenges to large desert-dwelling mammals. In addition to camels, antelopes within the Hippotraginae and Alcelaphinae subfamilies also exhibit remarkable physiological and genetic specializations for desert survival. Among them, the critically endangered addax ( Addax nasomaculatus) represents the most desert-adapted antelope species. However, the evolutionary and molecular mechanisms underlying desert adaptations remain largely unexplored. Herein, a high-quality genome assembly of the addax was generated to investigate the molecular evolution of desert adaptation in camels and desert antelopes. Comparative genomic analyses identified 136 genes harboring convergent amino acid substitutions implicated in crucial biological processes, including water reabsorption, fat metabolism, and stress response. Notably, a convergent R146S amino acid mutation in the prostaglandin EP2 receptor gene PTGER2 significantly reduced receptor activity, potentially facilitating large-mammal adaptation to arid environments. Lineage-specific innovations were also identified in desert antelopes, including previously uncharacterized conserved non-coding elements. Functional assays revealed that several of these elements exerted significant regulatory effects in vitro, suggesting potential roles in adaptive gene expression. Additionally, signals of introgression and variation in genetic load were observed, indicating their possible influence on desert adaptation. These findings provide insights into the sequential evolutionary processes that drive physiological resilience in arid environments and highlight the importance of convergent evolution in shaping adaptive traits in large terrestrial mammals.