Hidden hotspots of amphibian biodiversity in China.

Identifying and protecting hotspots of endemism and species richness is crucial for mitigating the global biodiversity crisis. However, our understanding of spatial diversity patterns is far from complete, which severely limits our ability to conserve biodiversity hotspots. Here, we report a comprehensive analysis of amphibian species diversity in China, one of the most species-rich countries on Earth. Our study combines 20 y of field surveys with new molecular analyses of 521 described species and also identifies 100 potential cryptic species. We identify 10 hotspots of amphibian diversity in China, each with exceptional species richness and endemism and with exceptional phylogenetic diversity and phylogenetic endemism (based on a new time-calibrated, species-level phylogeny for Chinese amphibians). These 10 hotspots encompass 59.6% of China's described amphibian species, 49.0% of cryptic species, and 55.6% of species endemic to China. Only four of these 10 hotspots correspond to previously recognized biodiversity hotspots. The six new hotspots include the Nanling Mountains and other mountain ranges in South China. Among the 186 species in the six new hotspots, only 9.7% are well covered by protected areas and most (88.2%) are exposed to high human impacts. Five of the six new hotspots are under very high human pressure and are in urgent need of protection. We also find that patterns of richness in cryptic species are significantly related to those in described species but are not identical.

The highest-elevation frog provides insights into mechanisms and evolution of defenses against high UV radiation.

Defense against ultraviolet (UV) radiation exposure is essential for survival, especially in high-elevation species. Although some specific genes involved in UV response have been reported, the full view of UV defense mechanisms remains largely unexplored. Herein, we used integrated approaches to analyze UV responses in the highest-elevation frog, Nanorana parkeri. We show less damage and more efficient antioxidant activity in skin of this frog than those of its lower-elevation relatives after UV exposure. We also reveal genes related to UV defense and a corresponding temporal expression pattern in N. parkeri. Genomic and metabolomic analysis along with large-scale transcriptomic profiling revealed a time-dependent coordinated defense mechanism in N. parkeri. We also identified several microRNAs that play important regulatory roles, especially in decreasing the expression levels of cell cycle genes. Moreover, multiple defense genes (i.e., TYR for melanogenesis) exhibit positive selection with function-enhancing substitutions. Thus, both expression shifts and gene mutations contribute to UV adaptation in N. parkeri. Our work demonstrates a genetic framework for evolution of UV defense in a natural environment.

A set of principles and practical suggestions for equitable fieldwork in biology.

Field biology is an area of research that involves working directly with living organisms in situ through a practice known as "fieldwork." Conducting fieldwork often requires complex logistical planning within multiregional or multinational teams, interacting with local communities at field sites, and collaborative research led by one or a few of the core team members. However, existing power imbalances stemming from geopolitical history, discrimination, and professional position, among other factors, perpetuate inequities when conducting these research endeavors. After reflecting on our own research programs, we propose four general principles to guide equitable, inclusive, ethical, and safe practices in field biology: be collaborative, be respectful, be legal, and be safe. Although many biologists already structure their field programs around these principles or similar values, executing equitable research practices can prove challenging and requires careful consideration, especially by those in positions with relatively greater privilege. Based on experiences and input from a diverse group of global collaborators, we provide suggestions for action-oriented approaches to make field biology more equitable, with particular attention to how those with greater privilege can contribute. While we acknowledge that not all suggestions will be applicable to every institution or program, we hope that they will generate discussions and provide a baseline for training in proactive, equitable fieldwork practices.

Species Persistence with Hybridization in Toad-Headed Lizards Driven by Divergent Selection and Low Recombination.

Speciation plays a central role in evolutionary studies, and particularly how reproductive isolation (RI) evolves. The origins and persistence of RI are distinct processes that require separate evaluations. Treating them separately clarifies the drivers of speciation and then it is possible to link the processes to understand large-scale patterns of diversity. Recent genomic studies have focused predominantly on how species or RI originate. However, we know little about how species persist in face of gene flow. Here, we evaluate a contact zone of two closely related toad-headed lizards (Phrynocephalus) using a chromosome-level genome assembly and population genomics. To some extent, recent asymmetric introgression from Phrynocephalus putjatai to P. vlangalii reduces their genomic differences. However, their highly divergent regions (HDRs) have heterogeneous distributions across the genomes. Functional gene annotation indicates that many genes within HDRs are involved in reproduction and RI. Compared with allopatric populations, contact areas exhibit recent divergent selection on the HDRs and a lower population recombination rate. Taken together, this implies that divergent selection and low genetic recombination help maintain RI. This study provides insights into the genomic mechanisms that drive RI and two species persistence in the face of gene flow during the late stage of speciation.

A vacuolar transporter plays important roles in zinc and cadmium accumulation in rice grain.

Rice grain is a poor dietary source of zinc (Zn) but the primary source of cadmium (Cd) for humans; however, the molecular mechanisms for their accumulation in rice grain remain incompletely understood. This study functionally characterized a tonoplast-localized transporter, OsMTP1. OsMTP1 was preferentially expressed in the roots, aleurone layer, and embryo of seeds. OsMTP1 knockout decreased Zn concentration in the root cell sap, roots, aleurone layer and embryo, and subsequently increased Zn concentration in shoots and polished rice (endosperm) without yield penalty. OsMTP1 haplotype analysis revealed elite alleles associated with increased Zn level in polished rice, mostly because of the decreased OsMTP1 transcripts. OsMTP1 expression in yeast enhanced Zn tolerance but did not affect that of Cd. While OsMTP1 knockout resulted in decreased uptake, translocation and accumulation of Cd in plant and rice grain, which could be attributed to the indirect effects of altered Zn accumulation. Our results suggest that rice OsMTP1 primarily functions as a tonoplast-localized transporter for sequestrating Zn into vacuole. OsMTP1 knockout elevated Zn concentration but prevented Cd deposition in polished rice without yield penalty. Thus, OsMTP1 is a candidate gene for enhancing Zn level and reducing Cd level in rice grains.

Impacts of climate change on herpetofauna diversity in the Qinghai-Tibetan Plateau.

Although numerous studies on the impacts of climate change on biodiversity have been published, only a handful are focused on the intraspecific level or consider population-level models (separate models per population). We endeavored to fill this knowledge gap relative to the Qinghai-Tibetan plateau (QTP) by combining species distribution modeling (SDMs) with population genetics (i.e., population-level models) and phylogenetic methods (i.e., phylogenetic tree reconstruction and phylogenetic diversity analyses). We applied our models to 11 endemic and widely distributed herpetofauna species inhabiting high elevations in the QTP. We aimed to determine the influence of environmental heterogeneity on species' responses to climate change, the magnitude of climate-change impacts on intraspecific diversity, and the relationship between species range loss and intraspecific diversity losses under 2 shared socioeconomic pathways (SSP245 and SSP585) and 3 future periods (2050s, 2070s, and 2090s). The effects of global climatic change were more pronounced at the intraspecific level (22% of haplotypes lost and 36% of populations lost) than the morphospecies level in the SSP585 climate change scenario. Maintenance of genetic diversity was in general determined by a combination of factors including range changes, species genetic structure, and the part of the range predicted to be lost. This is owing to the fact that the loss and survival of populations were observed in species irrespective of the predicted range changes (contraction or expansion). In the southeast (mountainous regions), climate change had less of an effect on range size (>100% in 3 species) than in central and northern QTP plateau regions (range size <100% in all species). This may be attributed to environmental heterogeneity, which provided pockets of suitable climate in the southeast, whereas ecosystems in the north and central regions were homogeneous. Generally, our results imply that mountainous regions with high environmental heterogeneity and high genetic diversity may buffer the adverse impacts of climate change on species distribution and intraspecific diversity. Therefore, genetic structure and characteristics of the ecosystem may be crucial for conservation under climate change.

Impactos del cambio climático sobre la diversidad de herpetofauna en la meseta Qinghai-Tíbet Región Aunque se han publicado numerosos estudios sobre los impactos del cambio climática en la biodiversidad, son muy pocos los que se enfocan en el nivel intraespecífico o que consideran modelos a nivel poblacional (modelos separados por población). Intentamos cerrar este vacío de conocimiento en relación con la meseta Qinghai-Tíbet (MQT) con la combinación entre modelos de distribución de especies (MDE) y genética poblacional (modelos a nivel poblacional) y métodos filogenéticos (reconstrucción de árboles filogenéticos y análisis de diversidad filogenética). Aplicamos nuestros modelos a once especies endémicas de herpetofauna con distribución amplia en las elevaciones más altas de la MQT. Nos planteamos determinar la influencia de la heterogeneidad de las especies sobre la respuesta de las especies al cambio climático, la magnitud de los impactos del cambio climático sobre la diversidad intraespecífica y la relación entre la pérdida de distribución de la especie y las pérdidas de diversidad intraespecífica bajo dos vías socioeconómicas (SSP245 y SSP585) y tres periodos del futuro (2050s, 2070s y 2090s). Los efectos del cambio climático global fueron más pronunciados a nivel intraespecífico (22% de pérdida en los haplotipos y 36% en las poblaciones) que al nivel morfoespecie en el escenario de cambio climático SSP585. El mantenimiento de la diversidad genética casi siempre estuvo determinado por una combinación de factores que incluyen cambios en la distribución, estructura genética de las especies y la parte de la distribución que se pronosticó se perdería. Esto se debe a que observamos la pérdida y supervivencia de las poblaciones sin importar los cambios pronosticados en la distribución (contracción o expansión). En las regiones montañosas del sureste, el cambio climático tuvo un efecto menor sobre la distribución (>100% en tres especies) comparado con las regiones de la meseta central y del norte de la MQT (distribución <100% en todas las especies). Esto puede atribuirse a la heterogeneidad ambiental, la cual proporciona recovecos de clima adecuado en el sureste, mientras que los ecosistemas en las regiones central y norte fueron homogéneos. De manera general, nuestros resultados implican que las regiones montañosas con una elevada heterogeneidad ambiental y una gran diversidad genética podrían reducir los impactos adversos del cambio climático sobre la distribución de las especies y la diversidad intraespecífica. Por lo tanto, la estructura genética y las características del ecosistema pueden ser cruciales para conservar bajo el cambio climático.

Anti-Tr/DNER antibody-associated cerebellar ataxia: three rare cases report and literature review.

BACKGROUND: To report three cases of autoimmune cerebellar ataxia related to anti-delta/notch-like epidermal growth factor-related receptor (Tr/DNER) antibodies. CASE PRESENTATION: Patients with unknown cerebellar ataxia were screened with autoimmune cerebellar ataxia (ACA)-related antibody panel. The anti-Tr antibody was positive in three female patients in whom the onset ages were 43 years, 35 years and 43 years old. The antibody titres of serum and cerebrospinal fluid were all 1:32. Cerebral ataxia was the most prominent presentation. Mild cerebellar atrophy was found in one of the patients. Immunotherapy was effective in all three patients. CONCLUSION: The Tr antibody is associated with autoimmune ataxia, and it has been suggested that the anti-Tr antibody should be tested in patients with cerebellar ataxia who are negative for routine ACA antibodies. Early immunotherapy may improve patient prognoses.

A transporter for delivering zinc to the developing tiller bud and panicle in rice.

Tiller number is one of the most important agronomic traits that determine rice (Oryza sativa) yield. Active growth of tiller bud (TB) requires high amount of mineral nutrients; however, the mechanism underlying the distribution of mineral nutrients to TB with low transpiration is unknown. Here, we found that the distribution of Zn to TB is mediated by OsZIP4, one of the ZIP (ZRT, IRT-like protein) family members. The expression of OsZIP4 was highly detected in TB and nodes, and was induced by Zn deficiency. Immunostaining analysis revealed that OsZIP4 was mainly expressed in phloem of diffuse vascular bundles in the nodes and the axillary meristem. The mutation of OsZIP4 did not affect the total Zn uptake, but altered Zn distribution; less Zn was delivered to TB and new leaf, but more Zn was retained in the basal stems at the vegetative growth stage. Bioimaging analysis showed that the mutant aberrantly accumulated Zn in enlarged and transit vascular bundles of the basal node, whereas in wild-type high accumulation of Zn was observed in the meristem part. At the reproductive stage, mutation of OsZIP4 resulted in delayed panicle development, which is associated with decreased Zn distribution to the panicles. Collectively, OsZIP4 is involved in transporting Zn to the phloem of diffuse vascular bundles in the nodes for subsequent distribution to TBs and other developing tissues. It also plays a role in transporting Zn to meristem cells in the TBs.

Phylogenomics Reveals Ancient Gene Tree Discordance in the Amphibian Tree of Life.

Molecular phylogenies have yielded strong support for many parts of the amphibian Tree of Life, but poor support for the resolution of deeper nodes, including relationships among families and orders. To clarify these relationships, we provide a phylogenomic perspective on amphibian relationships by developing a taxon-specific Anchored Hybrid Enrichment protocol targeting hundreds of conserved exons which are effective across the class. After obtaining data from 220 loci for 286 species (representing 94% of the families and 44% of the genera), we estimate a phylogeny for extant amphibians and identify gene tree-species tree conflict across the deepest branches of the amphibian phylogeny. We perform locus-by-locus genealogical interrogation of alternative topological hypotheses for amphibian monophyly, focusing on interordinal relationships. We find that phylogenetic signal deep in the amphibian phylogeny varies greatly across loci in a manner that is consistent with incomplete lineage sorting in the ancestral lineage of extant amphibians. Our results overwhelmingly support amphibian monophyly and a sister relationship between frogs and salamanders, consistent with the Batrachia hypothesis. Species tree analyses converge on a small set of topological hypotheses for the relationships among extant amphibian families. These results clarify several contentious portions of the amphibian Tree of Life, which in conjunction with a set of vetted fossil calibrations, support a surprisingly younger timescale for crown and ordinal amphibian diversification than previously reported. More broadly, our study provides insight into the sources, magnitudes, and heterogeneity of support across loci in phylogenomic data sets.[AIC; Amphibia; Batrachia; Phylogeny; gene tree-species tree discordance; genomics; information theory.].

Dual Drug Loaded pH-sensitive Micelles for Efficient Bacterial Infection Treatment.

PURPOSE: Methicillin-resistant Staphylococcus aureus (MRSA) infection at impaired wound is associated with high risks of developing to persistent bacterial infections since bacterial biofilm is easy to form in MRSA infected wounds. An advanced therapeutic approach to effectively penetrate and eliminate bacterial biofilm and to accelerate cell proliferation and migration at the wound is crucial. METHODS: The poly(ε-caprolactone)-monomethoxyl poly (ethylene glycol) (PCL-mPEG) micelles loaded with Quercetin and Rifampicin (QRMs) were prepared. Bacterial biofilm proliferation and elimination effect of QRMs were evaluated with confocal laser scanning microscopy. Antibacterial assay was further performed to detect antibacterial activity and mechanism. The cell scratch assay and cellular uptake were performed in HaCaT skin epithelial cells. RESULTS: Our results showed that the small sized QRMs could penetrate the interior of MRSA biofilm to disperse and eradicate biofilm. Then, antibiotics are released and accumulated in the acidic biofilm environment. QRMs could kill bacteria through increasing bacterial membrane permeability and altering membrane potential and membrane fluidity. Moreover, QRMs improved intracellular and cytoplasmic delivery efficiency of drugs to epithelial cells, and in the scratch test, presented a stronger ability to promote migration and proliferation of HaCaT cells compared with free drugs. Hemolysis test further proved good biocompatibility of QRMs. CONCLUSIONS: QRMs could potentially be used as a novel dual-functional nanotherapeutic for anti-bacterial infection by eradicating biofilm and accelerating cells proliferation at MRSA infected wound.

Genomic and transcriptomic investigations of the evolutionary transition from oviparity to viviparity.

Viviparous (live-bearing) vertebrates have evolved repeatedly within otherwise oviparous (egg-laying) clades. Over two-thirds of these changes in vertebrate reproductive parity mode happened in squamate reptiles, where the transition has happened between 98 and 129 times. The transition from oviparity to viviparity requires numerous physiological, morphological, and immunological changes to the female reproductive tract, including eggshell reduction, delayed oviposition, placental development for supply of water and nutrition to the embryo by the mother, enhanced gas exchange, and suppression of maternal immune rejection of the embryo. We performed genomic and transcriptomic analyses of a closely related oviparous-viviparous pair of lizards (Phrynocephalus przewalskii and Phrynocephalus vlangalii) to examine these transitions. Expression patterns of maternal oviduct through reproductive development of the egg and embryo differ markedly between the two species. We found changes in expression patterns of appropriate genes that account for each of the major aspects of the oviparity to viviparity transition. In addition, we compared the gene sequences in transcriptomes of four oviparous-viviparous pairs of lizards in different genera (Phrynocephalus, Eremias, Scincella, and Sphenomorphus) to look for possible gene convergence at the sequence level. We discovered low levels of convergence in both amino acid replacement and evolutionary rate shift. This suggests that most of the changes that produce the oviparity-viviparity transition are changes in gene expression, so occasional reversals to oviparity from viviparity may not be as difficult to achieve as has been previously suggested.

Role of a vacuolar iron transporter OsVIT2 in the distribution of iron to rice grains.

Iron (Fe) from rice grains is an important source of dietary intake; however, the molecular mechanisms responsible for loading of Fe to the grains are poorly understood. We functionally characterized a vacuolar iron transporter gene, OsVIT2 in terms of expression pattern, cellular localization, and mutant phenotypes. OsVIT2 was expressed in the parenchyma cell bridges of nodes, in the mestome sheath of leaf sheath and aleurone of the caryopsis. Mutation of OsVIT2 resulted in decreased Fe distribution to the leaf sheath, nodes, and aleurone, but increased Fe to the leaf blade and grains. Furthermore, Fe was heavily deposited in the parenchyma cell bridges, mestome sheath and aleurone in the wild-type rice, but this accumulation was decreased in the knockout lines. Conversely, heavier deposition of Fe was observed in the embryo and endosperm of the grains of knockout lines compared with the wild-type rice, resulting in increased Fe accumulation in the polished rice without yield penalty. These results indicate that OsVIT2 is involved in the distribution of Fe to the grains through sequestering Fe into vacuoles in mestome sheath, nodes, and aleurone layer and that knockout of this gene provides a potential way for Fe biofortification without yield penalty.

Multi-locus genetic analyses of Quasipaa from throughout its distribution.

Montane frogs of the genus Quasipaa Dubois, 1992 occur from southern China to Southeast Asia (Frost 2021). Analyses of mtDNA (Cytb) and nuDNA data (Rag1, Rag2, Rhod, Tyr) for samples from 93 localities throughout its distribution yield a phylogeny. Clades A and B occur in Southeast Asia, clade C in northern Yangtze River, China, clade D in southwestern China, and clades E and F in southeastern China. Results place Q. yei within monophyletic Quasipaa and identify two new species. Based on nuDNA data, the basal split of clade A and B indicates an Indochinese origin of Quasipaa. The west-east diversification of five species across South China (Q. spinosa, Q. exilispinosa, Q. jiulongensis, Q. shini, Q. boulengeri) corresponds to topographic terrains II and III of China. Divergence of species from southeastern China (Q. shini, Q. jiulongensis, Q. spinosa, Q. exilispinosa) and southwestern China (Q. boulengeri) dates to 15.30-16.56 Ma (million years ago). A principal component analysis (PCA) and t-test involving 19 bioclimatic variables identifies significantly different environmental conditions between the two regions. Species' distribution models (SDM) for Q. spinosa and Q. boulengeri identify the best areas to be eastern and western South China, respectively. Thus, environmental variation appears to have influenced the genetic divergence and distributions of Quasipaa in South China. Mito-nuclear discordance indicates that some individuals of Q. exilispinosa and Q. spinosa hybridized historically.

Using the 2020 global pandemic as a springboard to highlight the need for amphibian conservation in eastern Asia.

Emerging infectious diseases are on the rise in many different taxa, including, among others, the amphibian batrachochytrids, the snake fungal disease and the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) virus, responsible for Coronavirus disease 2019 (COVID-19) in mammals. Following the onset of the pandemic linked to COVID-19, eastern Asia has shown strong leadership, taking actions to regulate the trade of potential vector species in several regions. These actions were taken in response to an increase in public awareness, and the need for a quick reaction to mitigate against further pandemics. However, trade restrictions rarely affect amphibians, despite the risk of pathogen transmission, directly, or indirectly through habitat destruction and the loss of vector consumption. Thus, species that help alleviate the risk of zoonoses or provide biological control are not protected. Hence, in view of the global amphibian decline and the risk of zoonoses, we support the current wildlife trade regulations and support measures to safeguard wildlife from overexploitation. The current period of regulation overhaul should be used as a springboard for amphibian conservation. To mitigate risks, we suggest the following stipulations specifically for amphibians. I) Restrictions to amphibian farming in eastern Asia, in relation to pathogen transmission and the establishment of invasive species. II) Regulation of the amphibian pet trade, with a focus on potential vector species. III) Expansion of the wildlife trade ban, to limit the wildlife-human-pet interface. The resulting actions will benefit both human and wildlife populations, as they will lead to a decrease in the risk of zoonoses and better protection of the environment. SIGNIFICANCE STATEMENT: There is an increasing number of emerging infectious diseases impacting all species, including amphibians, reptiles and mammals. The latest threat to humans is the virus responsible for COVID-19, and the resulting pandemic. Countries in eastern Asia have taken steps to regulate wildlife trade and prevent further zoonoses thereby decreasing the risk of pathogens arising from wild species. However, as amphibians are generally excluded from regulations we support specific trade restrictions: I) Restrictions to amphibian farming; II) regulation of the amphibian pet trade; III) expansion of the wildlife trade ban. These restrictions will benefit both human and wildlife populations by decreasing the risks of zoonoses and better protecting the environment.

Comparison of Different Hydration Strategies in Patients with Very Low-Risk Profiles of Contrast-Induced Nephropathy.

BACKGROUND Hydration remains the mainstay of contrast-induced nephropathy (CIN) prevention, and new biomarkers of cystatin C (Cys C) and neutrophil gelatinase-associated lipocalin (NGAL) have been suggested. This study aimed to explore whether hydration is essential in patients with very low-risk profiles of CIN who are undergoing coronary angiography. MATERIAL AND METHODS A total of 150 patients were enrolled and randomly distributed to 3 groups: the Preventive Group (n=50, saline hydration was given 6 h before the procedure until 12 h after the procedure), the Remedial Group (n=50, saline hydration was given after procedure for 12 h), and the No Hydration (NH) group (n=50, saline was only given during the procedure). Serum creatinine (Cr), Cys C, and urinary NGAL were tested 3 times at different times. RESULTS Six patients were excluded because of Mehran risk score >2. There was no CIN among 144 individuals. At 24 h and at 72 h after the procedure, we found no significant differences in the levels of Cr and Cys C (0.72±0.11 mg/L for the Preventive Group, 0.67±0.14 mg/L for the Remedial Group, and 0.70±0.1 6 mg/L for the NH Group) among the 3 groups. Urinary NGAL also did not differ significantly among the 3 groups at 6 h or at 48 h (6.31±6.60 ng/ml for the Preventive Group, 5.00±5.86 ng/ml for the Remedial Group, and 6.97±6.37 ng/ml for the NH Group) after the procedure. Subgroup analysis in patients who underwent percutaneous coronary intervention (PCI) showed that there was no significant difference in serum Cr, Cys C, or urinary NGAL at different time points among the 3 groups. CONCLUSIONS Saline hydration during the perioperative period might be unnecessary in patients with very low-risk profiles of CIN.

Species groups distributed across elevational gradients reveal convergent and continuous genetic adaptation to high elevations.

Although many cases of genetic adaptations to high elevations have been reported, the processes driving these modifications and the pace of their evolution remain unclear. Many high-elevation adaptations (HEAs) are thought to have arisen in situ as populations rose with growing mountains. In contrast, most high-elevation lineages of the Qinghai-Tibetan Plateau appear to have colonized from low-elevation areas. These lineages provide an opportunity for studying recent HEAs and comparing them with ancestral low-elevation alternatives. Herein, we compare four frogs (three species of Nanorana and a close lowland relative) and four lizards (Phrynocephalus) that inhabit a range of elevations on or along the slopes of the Qinghai-Tibetan Plateau. The sequential cladogenesis of these species across an elevational gradient allows us to examine the gradual accumulation of HEA at increasing elevations. Many adaptations to high elevations appear to arise gradually and evolve continuously with increasing elevational distributions. Numerous related functions, especially DNA repair and energy metabolism pathways, exhibit rapid change and continuous positive selection with increasing elevations. Although the two studied genera are distantly related, they exhibit numerous convergent evolutionary changes, especially at the functional level. This functional convergence appears to be more extensive than convergence at the individual gene level, although we found 32 homologous genes undergoing positive selection for change in both high-elevation groups. We argue that species groups distributed along a broad elevational gradient provide a more powerful system for testing adaptations to high-elevation environments compared with studies that compare only pairs of high-elevation versus low-elevation species.

Selection and environmental adaptation along a path to speciation in the Tibetan frog Nanorana parkeri.

Tibetan frogs, Nanorana parkeri, are differentiated genetically but not morphologically along geographical and elevational gradients in a challenging environment, presenting a unique opportunity to investigate processes leading to speciation. Analyses of whole genomes of 63 frogs reveal population structuring and historical demography, characterized by highly restricted gene flow in a narrow geographic zone lying between matrilines West (W) and East (E). A population found only along a single tributary of the Yalu Zangbu River has the mitogenome only of E, whereas nuclear genes of W comprise 89-95% of the nuclear genome. Selection accounts for 579 broadly scattered, highly divergent regions (HDRs) of the genome, which involve 365 genes. These genes fall into 51 gene ontology (GO) functional classes, 14 of which are likely to be important in driving reproductive isolation. GO enrichment analyses of E reveal many overrepresented functional categories associated with adaptation to high elevations, including blood circulation, response to hypoxia, and UV radiation. Four genes, including DNAJC8 in the brain, TNNC1 and ADORA1 in the heart, and LAMB3 in the lung, differ in levels of expression between low- and high-elevation populations. High-altitude adaptation plays an important role in maintaining and driving continuing divergence and reproductive isolation. Use of total genomes enabled recognition of selection and adaptation in and between populations, as well as documentation of evolution along a stepped cline toward speciation.

Loading doses of ticagrelor versus clopidogrel in preventing periprocedural myocardial infarction in Asian patients with acute coronary syndrome.

BACKGROUND: Periprocedural myocardial infarction is a common complication following percutaneous coronary intervention. The present study was conducted with an aim to compare the safety and efficacy of loading doses of ticagrelor versus clopidogrel in preventing periprocedural myocardial infarction in Asian patients with acute coronary syndrome undergoing elective percutaneous coronary intervention. METHODS: A total of 114 patients with acute coronary syndrome undergoing elective percutaneous coronary intervention were assigned to clopidogrel group (n = 57, the loading and maintenance doses were 300 and 75 mg qd for clopidogrel, and 300 and 100 mg qd for aspirin), or ticagrelor group (n = 57, the loading and maintenance doses were 180 and 90 mg bid for ticagrelor, and 300 and 100 mg qd for aspirin). Cardiac biomarkers were measured before, 8 hours, and 24 hours after percutaneous coronary intervention. The percutaneous coronary intervention-related periprocedural myocardial infarction was defined according to the fourth universal definition of myocardial infarction (2018). RESULTS: The overall incidence of percutaneous coronary intervention-related periprocedural myocardial infarction was 21.1%. The ticagrelor group showed a significantly lower incidence of periprocedural myocardial infarction (12.3% vs 29.8%, p = 0.022) and numerically lower bleeding events (3.5% vs 8.8%, p = 0.242) as compared with clopidogrel group. No patient had major adverse cardiovascular events during the 1-month follow-up. The levels of high-sensitivity C-reactive protein did not differ significantly between the two groups (p > 0.05), indicating that the benefits of ticagrelor were not from its anti-inflammatory effects. Multivariable analysis showed that the use of ticagrelor (odds ratio: 0.50; 95% confidence interval: 0.29-0.87; p = 0.014) and number of stents (odds ratio: 2.75; 95% confidence interval: 1.25-6.06; p = 0.012) were independent predictors of periprocedural myocardial infarction. CONCLUSION: Pretreatment with a loading dose of ticagrelor seems to be superior in reducing the incidence of percutaneous coronary intervention-related periprocedural myocardial infarction in Asian patients with acute coronary syndrome as compared with clopidogrel.

Node-Localized Transporters of Phosphorus Essential for Seed Development in Rice.

About 60-85% of total phosphorus (P) in cereal crops is finally allocated to seeds, where it is required for seed development, germination and early growth. However, little is known about the molecular mechanisms underlying P allocation to seeds. Here, we found that two members (OsPHO1;1 and OsPHO1;2) of the PHO1 gene family are involved in the distribution of P to seeds in rice. Both OsPHO1;1 and OsPHO1;2 were localized to the plasma membrane and showed influx transport activities for inorganic phosphate. At the reproductive stage, both OsPHO1;1 and OsPHO1;2 showed higher expression in node I, the uppermost node connecting to the panicle. OsPHO1;1 was mainly localized at the phloem region of diffuse vascular bundles (DVBs) of node I, while OsPHO1;2 was expressed in the xylem parenchyma cells of the enlarged vascular bundles (EVBs). In addition, they were also expressed in the ovular vascular trace, the outer layer of the inner integument (OsPHO1;1) and in the nucellar epidermis (OsPHO1;2) of caryopses. Knockout of OsPHO1;2, as well as OsPHO1;1 to a lesser extent, decreased the distribution of P to the seed, resulting in decreased seed size and delayed germination. Taken together, OsPHO1;2 expressed in node I is responsible for the unloading of P from the xylem of EVBs, while OsPHO1;1 is involved in reloading P into the phloem of DVBs for subsequent allocation of P to seeds. Furthermore, OsPHO1;1 and OsPHO1;2 expression in the caryopsis is important for delivering P from the maternal tissues to the filial tissues for seed development.

A Vacuolar Phytosiderophore Transporter Alters Iron and Zinc Accumulation in Polished Rice Grains.

Essential metals, such as iron (Fe) and zinc (Zn), in grains are important sources for seed germination and nutritional requirements, but the molecular mechanisms underlying their loading into grains are poorly understood. Recently, nodes in rice (Oryza sativa) were reported to play an important role in the preferential distribution of mineral elements to the grains. In this study, we functionally characterized a rice gene highly expressed in nodes, OsVMT (VACUOLAR MUGINEIC ACID TRANSPORTER), belonging to a major facilitator superfamily. OsVMT is highly expressed in the parenchyma cell bridges of node I, where Fe and Zn are highly deposited. The expression of OsVMT was induced by Fe deficiency in the roots but not in the shoot basal region and uppermost node. OsVMT localized to the tonoplast and showed efflux transport activity for 2'-deoxymugineic acid (DMA). At the vegetative stage, knockout of OsVMT resulted in decreased DMA but increased ferric Fe in the root cell sap. As a result, the concentration of DMA in the xylem sap increased but that of ferric Fe decreased in the xylem sap in the mutants. In the polished rice grain, the mutants accumulated 1.8- to 2.1-fold, 1.5- to 1.6-fold, and 1.4- to 1.5-fold higher Fe, Zn, and DMA, respectively, than the wild type. Taken together, our results indicate that OsVMT is involved in sequestering DMA into the vacuoles and that knockout of this gene enhances the accumulation of Fe and Zn in polished rice grains through DMA-increased solubilization of Fe and Zn deposited in the node.