Origin of the OAS-RNase L innate immune pathway before the rise of jawed vertebrates via molecular tinkering.

Discriminating self from nonself is fundamental to immunity. Yet, it remains largely elusive how the mechanisms of self and nonself discrimination originated. Sensing double-stranded RNA as nonself, the 2',5'-oligoadenylate synthetase (OAS)-ribonuclease L (RNase L) pathway represents a crucial component of innate immunity. Here, we combine phylogenomic and functional analyses to show that the functional OAS-RNase L pathway likely originated through tinkering with preexisting proteins before the rise of jawed vertebrates during or before the Silurian period (444 to 419 Mya). Multiple concerted losses of OAS and RNase L occurred during the evolution of jawed vertebrates, further supporting the ancient coupling between OAS and RNase L. Moreover, both OAS and RNase L genes evolved under episodic positive selection across jawed vertebrates, suggesting a long-running evolutionary arms race between the OAS-RNase L pathway and microbes. Our findings illuminate how an innate immune pathway originated via molecular tinkering.

The distribution and drivers of microbial pigments in the cryoconite of four Tibetan glaciers.

Microbial pigments play a significant role in glacier albedo reduction, thereby contributing to accelerated glacier retreat. The Tibetan Plateau has experienced rapid glacier retreat in recent decades due to global warming, yet there is limited understanding of microbial pigment distribution in the region. Here, we investigated the pigment concentration and composition in cryoconite from four glaciers. Our results showed that chlorophylls were the dominant pigments in Palong No. 4 (PL) and Jiemayangzong (JMYZ) glaciers located in the south of the Tibetan Plateau, while carotenoids were dominant in Qiangyong (QY) and Tanggula (TGL) glaciers located in the central region. Additionally, the chlorophyll b to chlorophyll a ratio, which is an indicator of the algae-to-cyanobacteria ratio, was higher in PL and JMYZ compared to QY and TGL. By using Random Forest Regression and Structural Equation Modelling, we determined that the concentrations of chlorophyll a, chlorophyll b, and carotenoids were associated with autotrophic bacteria relative abundance, climatic factors, and a combination of bacterial and climatic factors, respectively. This study is the first to describe the distribution of microbial pigments in cryoconite from Tibetan glaciers, providing additional support on the influence of algal pigment on glacier retreat.

A Long-Running Arms Race between APOBEC1 Genes and Retroviruses in Tetrapods.

Activation-induced cytidine deaminase/apolipoprotein B mRNA editing catalytic polypeptide-like (AID/APOBEC) proteins are cytosine deaminases implicated in diverse biological functions. APOBEC1 (A1) proteins have long been thought to regulate lipid metabolism, whereas the evolutionary significance of A1 proteins in antiviral defense remains largely obscure. Endogenous retroviruses (ERVs) document past retroviral infections and are ubiquitous within the vertebrate genomes. Here, we identify the A1 gene repertoire, characterize the A1-mediated mutation footprints in ERVs, and interrogate the evolutionary arms race between A1 genes and ERVs across vertebrate species. We find that A1 genes are widely present in tetrapods, recurrently amplified and lost in certain lineages, suggesting that A1 genes might have originated during the early evolution of tetrapods. A1-mediated mutation footprints can be detected in ERVs across tetrapods. Moreover, A1 genes appear to have experienced episodic positive selection in many tetrapod lineages. Taken together, we propose that a long-running arms race between A1 genes and retroviruses might have persisted throughout the evolutionary course of tetrapods. IMPORTANCE APOBEC3 (A3) genes have been thought to function in defense against retroviruses, whereas the evolutionary significance of A1 proteins in antiviral defense remains largely obscure. In this study, we identify the A1 gene repertoire, characterize the A1-mediated mutation footprints in endogenous retroviruses (ERVs), and explore the evolutionary arms race between A1 genes and ERVs across vertebrate species. We found A1 proteins originated during the early evolution of tetrapods, and detected the footprints of A1-induced hypermutations in retroviral fossils. A1 genes appear to have experienced pervasive positive selection in tetrapods. Our study indicates a long-running arms race between A1 genes and retroviruses taking place throughout the evolutionary course of tetrapods.

Improving the ionic conductivity of polymer electrolytes induced by ceramic nanowire fillers with abundant lithium vacancies.

The addition of ceramic fillers is regarded as an effective strategy for enhancing the ionic conductivity of polymer electrolytes. However, particulate fillers typically fail to provide continuous conductive pathways and effective reinforcement. Herein, we report a ceramic nanowire filler with long-range interfacial conductivity and abundant lithium vacancies for a poly(ethylene oxide) (PEO)-based all-solid-state polymer electrolyte. LLZO nanowires (LLZO NWs) with a high aspect ratio are synthesized by combining sol-gel electrospinning and the multi-step process involving pre-oxidation, pre-sintering, and secondary sintering, resulting in a high tensile strength of the composite electrolyte (6.87 MPa). Notably, tantalum-aluminum co-substituted LLZO NWs (TALLZO NWs) release abundant lithium vacancies, further enhancing the Lewis acid-base properties, leading to a rapid ion migration speed (Li+ transfer number = 0.79) and significantly high ionic conductivity (3.80 × 10-4 S cm-1). Due to the synergistic effect of nanostructure modification and heteroatom co-doping, the assembled all-solid-state lithium-sulfur battery exhibits a high initial discharge capacity (776 mA h g-1 at 25 °C), remarkable rate capability, and excellent cycling performance (81% capacity retention after 200 cycles at 0.1C).

Portal vein velocity predicts portal vein system thrombosis after splenectomy with esophagogastric devascularization.

BACKGROUND: Portal vein system thrombosis (PVST) is a potentially fatal complication after splenectomy with esophagogastric devascularization (SED) in cirrhotic patients with portal hypertension. However, the impact of portal vein velocity (PVV) on PVST after SED remains unclear. Therefore, this study aims to explore this issue. METHODS: Consecutive cirrhotic patients with portal hypertension who underwent SED at Tongji Hospital between January 2010 and June 2022 were enrolled. The patients were divided into two groups based on the presence or absence of PVST, which was assessed using ultrasound or computed tomography after the operation. PVV was measured by duplex Doppler ultrasound within one week before surgery. The independent risk factors for PVST were analyzed using univariate and multivariate logistic regression analysis. A nomogram based on these variables was developed and internally validated using 1000 bootstrap resamples. RESULTS: A total of 562 cirrhotic patients with portal hypertension who underwent SED were included, and PVST occurred in 185 patients (32.9%). Multivariate logistic regression analysis showed that PVV was the strongest independent risk factor for PVST. The incidence of PVST was significantly higher in patients with PVV ≤ 16.5 cm/s than in those with PVV > 16.5 cm/s (76.2% vs. 8.5%, p < 0.0001). The PVV-based nomogram was internally validated and showed good performance (optimism-corrected c-statistic = 0.907). Decision curve and clinical impact curve analyses indicated that the nomogram provided a high clinical benefit. CONCLUSION: A nomogram based on PVV provided an excellent preoperative prediction of PVST after splenectomy with esophagogastric devascularization.

The mediating role of children's intergenerational support in association between grandparenting and cognitive function among middle-aged and older Chinese: findings from the CHARLS cohort study.

OBJECTIVES: With the world's population increasing in age, there has been a significant rise in the prevalence of cognitive impairment and dementia among individuals. This study aims to investigate the association between grandparenting and cognitive function among middle-aged and older Chinese using data from 2011 to 2018 China Health and Retirement Longitudinal Study (CHARLS). Additionally, the study seeks to explore the potential mediating effect of intergenerational support from children on this relationship, using data from the CHARLS 2011 database. METHODS: 5254 participants were recruited at the baseline survey in CHARLS 2011. Subsequently, a follow-up survey was conducted over 8 years, from CHARLS 2011 to 2018, with 1472 individuals completing the follow-up survey. The CHARLS included surveys on grandparenting and cognitive assessments. Grandparenting was categorized as yes and no. The assessment of cognitive function involved the evaluation of episodic memory and mental intactness. The present study used cross-sectional and longitudinal analyses to examine the relationship between grandparenting and cognitive function. The bootstrap method assessed the mediating effect of children's intergenerational support. RESULTS: The results of both cross-sectional and longitudinal studies indicated a positive association between grandparenting and cognitive function in middle-aged and older Chinese (B = 0.138, p < 0.05; B = 0.218, p < 0.05). Children's emotional and economic support played intermediary roles between grandparenting and cognitive function. CONCLUSION: The results emphasized the significance of policymakers considering the consequences of intergenerational care and family support when formulating and executing social service policies targeted at the middle-aged and older population in China.

Advancements in Thermal Insulation through Ceramic Micro-Nanofiber Materials.

Ceramic fibers have the advantages of high temperature resistance, light weight, favorable chemical stability and superior mechanical vibration resistance, which make them widely used in aerospace, energy, metallurgy, construction, personal protection and other thermal protection fields. Further refinement of the diameter of conventional ceramic fibers to microns or nanometers could further improve their thermal insulation performance and realize the transition from brittleness to flexibility. Processing traditional two-dimensional (2D) ceramic fiber membranes into three-dimensional (3D) ceramic fiber aerogels could further increase porosity, reduce bulk density, and reduce solid heat conduction, thereby improving thermal insulation performance and expanding application areas. Here, a comprehensive review of the newly emerging 2D ceramic micro-nanofiber membranes and 3D ceramic micro-nanofiber aerogels is demonstrated, starting from the presentation of the thermal insulation mechanism of ceramic fibers, followed by the summary of 2D ceramic micro-nanofiber membranes according to different types, and then the generalization of the construction strategies for 3D ceramic micro-nanofiber aerogels. Finally, the current challenges, possible solutions, and future prospects of ceramic micro-nanofiber materials are comprehensively discussed. We anticipate that this review could provide some valuable insights for the future development of ceramic micro-nanofiber materials for high temperature thermal insulation.

Research on the Interaction Mechanism and Structural Changes in Human Serum Albumin with Hispidin Using Spectroscopy and Molecular Docking.

The interaction between human serum albumin (HSA) and hispidin, a polyketide abundantly present in both edible and therapeutic mushrooms, was explored through multispectral methods, hydrophobic probe assays, location competition trials, and molecular docking simulations. The results of fluorescence quenching analysis showed that hispidin quenched the fluorescence of HSA by binding to it via a static mechanism. The binding of hispidin and HSA was validated further by synchronous fluorescence, three-dimensional fluorescence, and UV/vis spectroscopy analysis. The apparent binding constant (Ka) at different temperatures, the binding site number (n), the quenching constants (Ksv), the dimolecular quenching rate constants (Kq), and the thermodynamic parameters (∆G, ∆H, and ∆S) were calculated. Among these parameters, ∆H and ∆S were determined to be 98.75 kJ/mol and 426.29 J/(mol·K), respectively, both exhibiting positive values. This observation suggested a predominant contribution of hydrophobic forces in the interaction between hispidin and HSA. By employing detergents (SDS and urea) and hydrophobic probes (ANS), it became feasible to quantify alterations in Ka and surface hydrophobicity, respectively. These measurements confirmed the pivotal role of hydrophobic forces in steering the interaction between hispidin and HSA. Site competition experiments showed that there was an interaction between hispidin and HSA molecules at site I, which situates the IIA domains of HSA, which was further confirmed by the molecular docking simulation.

Anatomical sectionectomy based on Takasaki's segmentation for solitary intrahepatic cholangiocarcinoma: a propensity-matched analysis.

BACKGROUND: Anatomical sectionectomy based on Takasaki's segmentation has shown advantages in hepatocellular carcinoma. However, whether this approach improves the survival of intrahepatic cholangiocarcinoma (ICC) remains unknown. METHODS: A series of 248 consecutive patients with solitary ICCs who underwent hepatectomy were studied retrospectively. The patients were classified into the groups of anatomical sectionectomy based on Takasaki's segmentation (TS group) and non-Takasaki's hepatectomy (NTH group). The bias between the two groups was minimized using propensity score matching (PSM). Recurrence-free survival (RFS) and overall survival (OS) were evaluated with Kaplan-Meier analysis. The Cox proportional hazards model was performed to determine the adverse risk factors associated with survival. RESULTS: After PSM, 67 pairs of patients were compared. Both the RFS and OS rates in the TS group were significantly better than those in the NTH group (23.2 % vs. 16.5 %, and 40.4 % vs. 27.3 %, P = 0.035 and 0.032, respectively). Multivariate analysis showed that NTH was independently associated with worse RFS and OS than TS. The stratified analysis demonstrated that the RFS and OS rates in the TS group with tumor stage I and tumor size ≥3 cm were significantly better than those in the NTH group, while the survival rates for ICC with stage I and tumor size <3 cm or stage II-III showed no significant difference. CONCLUSION: TS was associated with improved RFS and OS in patients with solitary ICC even after PSM. TS may be preferred particularly in patients with tumor stage I and tumor size ≥3 cm.

A Conductive Binder Based on Mesoscopic Interpenetration with Polysulfides Capturing Skeleton and Redox Intermediates Network for Lithium Sulfur Batteries.

The practical application of lithium-sulfur batteries with high theoretical energy density and readily available cathode active materials is hampered by problems such as sulfur insulation, dramatic volume changes, and polysulfide shuttling. The targeted development of novel binders is the most industrialized solution to the problem of sulfur cathodes. Herein, an aqueous conductive emulsion binder with the sulfonate-containing hard elastic copolymer core and the conjugate polymer shell, which is capable of forming a bicontinuous mesoscopic interpenetrating polymer network, is synthesized and investigated. Not only can the elastic skeleton formed by the copolymer bind the active substance under drastic volume changes, but also the rich ester and cyanide groups in it can effectively capture lithium polysulfide. Meanwhile, the conducting skeleton consisting of poly(3,4-ethylenedioxythiophene) both provides the additional charge conduction pathways and acts as the redox intermediates, significantly accelerating the kinetic process of lithium polysulfide conversion. Based on the synergistic effect of the above mechanisms, the use of the prepared binder on the sulfur carbon cathode significantly improves the rate performance and cycle stability of lithium sulfur batteries.

Long-lifespan Zinc-ion Capacitors Enabled by Anodes Integrated with Interconnected Mesoporous Chitosan Membranes through Electrophoresis-driven Phase Separation.

The advancement of highly secure and inexpensive aqueous zinc ion energy storage devices is impeded by issues, including dendrite growth, hydrogen evolution and corrosion of zinc anodes. It is essential to modify the interface of zinc anodes that homogenizes ion flux and facilitates highly reversible zinc planarized deposition and stripping. Herein, by coupling zinc ion coordination with acid-base neutralization under the driving of electrophoresis, manageable mesoscopic phase separation for constructing chitosan frameworks was achieved, thereby fabricating interconnected mesoporous chitosan membranes based heterogeneous quasi-solid-state electrolytes integrated with anodes. The framework is constructed by twisted chitosan nanofiber bundles, forming a three-dimensional continuous spindle-shaped pore structure. With this framework, the electrolyte provides exceptional ion conductivity of 25.1 mS cm-1 , with a puncture resistance strength of 2.3 GPa. In addition, the amino groups of chitosan molecule can make the surface of the framework positively charged. Thus, reversible zinc planarized deposition is successfully induced by the synergistic effect of stress constraint and electrostatic modulation. As a result, as-assembled zinc ion capacitor has an excellent cycle life and sustains the capacity by over 95 % after 20000 cycles at a current density of 5 A g-1 . This research presents a constructive strategy for stable electrolytes-integrated zinc anodes.

Wheat cis-zeatin-O-glucosyltransferase cZOGT1 interacts with the Ca2+-dependent lipid binding protein TaZIP to regulate senescence.

Premature senescence is an important factor affecting wheat yield and quality. Wheat yield can be increased by delaying senescence and prolonging the effective photosynthetic time. Previously, we found that the cis-zeatin-O-glucosyltransferase (cZOGT1) gene plays an important role in the stay-green wheat phenotype. In this study, cZOGT1-overexpressing lines exhibited a delayed senescence phenotype, despite a significant reduction in the total cytokinin content. Further, we found that cZOGT1 interacted with the Ca2+-dependent lipid binding protein TaZIP (cZOGT1-interacting protein), and that a high level of cZOGT1 expression led to the suppression of TaZIP expression, which in turn, reduced abscisic acid (ABA) content. The synergistic reduction in cytokinins and ABA levels eventually caused the stay-green phenotype in cZOGT1-overexpressing lines. This study provides a new theoretical basis to explain the mechanism underlying the wheat stay-green phenotype and provides a genetic resource for wheat molecular-design breeding.

Comparative immunological landscape between pre- and early-stage LUAD manifested as ground-glass nodules revealed by scRNA and scTCR integrated analysis.

BACKGROUND: Mechanism underlying the malignant progression of precancer to early-stage lung adenocarcinoma (LUAD) as well as their indolence nature remains elusive. METHODS: Single-cell RNA sequencing (scRNA) with simultaneous T cell receptor (TCR) sequencing on 5 normal lung tissues, 3 precancerous and 4 early-stage LUAD manifested as pulmonary ground-glass nodules (GGNs) were performed. RESULTS: Through this integrated analysis, we have delineated five key modules that drive the malignant progression of early-stage LUAD in a disease stage-dependent manner. These modules are related to cell proliferation and metabolism, immune response, mitochondria, cilia, and cell adhesion. We also find that the tumor micro-environment (TME) of early-stage LUAD manifested as GGN are featured with regulatory T (Tregs) cells accumulation with three possible origins, and loss-functional state (decreased clonal expansion and cytotoxicity) of CD8 + T cells. Instead of exhaustion, the CD8 + T cells are featured with a shift to memory phenotype, which is significantly different from the late stage LUAD. Furthermore, we have identified monocyte-derived macrophages that undergo a lipid-phenotype transition and may contribute to the suppressive TME. Intense interaction between stromal cells, myeloid cells including lipid associated macrophages and LAMP3 + DCs, and lymphocytes were also characterized. CONCLUSIONS: Our work provides new insight into the molecular and cellular mechanism underlying malignant progression of LUAD manifested as GGN, and pave way for novel immunotherapies for GGN. Video Abstract.

Serious Risk of Tigecycline Resistance in Escherichia coli Isolated from Swine Manure.

The emergence of the plasmid-mediated tigecycline resistance gene tetX family in pig farms has attracted worldwide attention. The use of tetracycline antibiotics in pig farms has a facilitating effect on the prevalence of the tetX family, but the relationship among its presence, expression, and resistance phenotype in resistant bacteria is unknown. In this study, the presence and expression characteristics of tetracycline resistance genes (TRGs) in 89 strains of doxycycline-resistant E. coli (DRE) isolated from pig manure samples from 20 pig farms under low concentrations of doxycycline stress (2 µg/mL) were analyzed. The detection rate of tetO was 96.63%, which is higher than those of other TRGs, such as tetA (94.38%), tetX (76.40%), tetB (73.03%), and tet(X4) (69.66%). At least three TRG types were present in DRE strains, which thus showed extensive resistance to tetracycline antibiotics, and 37% of these strains were resistant to tigecycline. In the presence of a low concentration of doxycycline, tetA played an important role, and the expression and existence ratio of TRGs indicated low expression of TRGs. Furthermore, the doxycycline resistance of DRE was jointly determined by the total absolute abundance of TRGs, and the absolute abundance of tetX and tet(X4) was significantly positively associated with tigecycline resistance in DRE (P < 0.05). Overall, DRE isolated from swine manure is an important reservoir of the tetX family, which suggests that DRE in swine manure has a high risk of tigecycline resistance, poses a potential threat to human health, and should be of public concern.

Development of transgenic composite Stylosanthes plants to study root growth regulated by a ß-expansin gene, SgEXPB1, under phosphorus deficiency.

KEY MESSAGE: A highly efficient transformation procedure to generate transgenic Stylosanthes roots was established. SgEXPB1 is involved in Stylosanthes root growth under phosphorus deficiency. Stylo (Stylosanthes spp.) is an important forage legume widely applied in agricultural systems in the tropics. Due to the recalcitrance of stylo genetic transformation, functional characterization of candidate genes involved in stylo root growth is limited. This study established an efficient procedure for Agrobacterium rhizogenes-mediated transformation for generating transgenic composite plants of S. guianensis cultivar 'Reyan No. 5'. Results showed that composite stylo plants with transgenic hairy roots were efficiently generated by A. rhizogenes strains K599 and Arqual, infecting the residual hypocotyl at 1.0 cm of length below the cotyledon leaves of 9-d-old seedlings, leading to a high transformation efficiency of > 95% based on histochemical ß-glucuronidase (GUS) staining. Notably, 100% of GUS staining-positive hairy roots can be achieved per composite stylo plant. Subsequently, SgEXPB1, a ß-expansin gene up-regulated by phosphorus (P) deficiency in stylo roots, was successfully overexpressed in hairy roots. Analysis of hairy roots showed that root growth and P concentration in the transgenic composite plants were increased by SgEXPB1 overexpression under low-P treatment. Taken together, a highly efficient A. rhizogenes-mediated transformation procedure for generating composite stylo plants was established to study the function of SgEXPB1, revealing that this gene is involved in stylo root growth during P deficiency.

Pervasive Positive Selection on Virus Receptors Driven by Host-Virus Conflicts in Mammals.

Viruses hijack cellular proteins, known as viral receptors, to initiate their infections. Viral receptors are subject to two conflicting directional forces, namely, negative selection to maintain their cellular function and positive selection resulted from the ever-changing host-virus arms race. Much remains unclear about how viral receptors evolved in mammals and whether viral receptors from different mammal groups experienced different strengths of natural selection. Here, we perform evolutionary analyses of 92 viral receptors in five major orders of mammals, including Carnivora, Cetartiodactyla, Chiroptera, Primates, and Rodentia. In all five mammal orders, signals of positive selection are detected for a high proportion of viral receptors (from 41% in Carnivora to 65% in Rodentia). Many positively selected residues overlap the host-virus interaction interface. Compared with control genes, we find viral receptors underwent elevated rates of adaptive evolution in all five mammal orders, suggesting that host-virus conflicts are the main driver of the adaptive evolution of viral receptors in mammals. Interestingly, the overall strength of natural selection acting on viral receptors driven by the host-virus arms race is largely homogenous and correlated among different mammal orders, with bats and rodents, zoonosis reservoirs of importance, being unexceptional. Taken together, our findings indicate host-virus conflicts have driven the elevated rate of adaptive evolution in viral receptors across mammals and might have important implications in zoonosis surveillance and prediction. IMPORTANCE Viral receptors are cellular proteins hijacked by viruses to help their infections. A complete picture on the evolution of viral receptors in mammals is still lacking. Here, we perform a comprehensive evolutionary analysis of the evolution of 92 viral receptors in five mammal orders, including Carnivora, Cetartiodactyla, Chiroptera, Primates, and Rodentia. We find that positive selection pervasively occurred during the evolution of viral receptors, and viral receptors exhibit an elevated rate of adaptive evolution compared to that of control genes in all five mammal orders, suggesting host-virus conflicts are a major driver of the adaptive evolution of viral receptors. Interestingly, the strength of positive selection acting on viral receptors is similar among the five mammal orders. Our study might have important implications in understanding the evolution of host-virus interaction.

A unique feature of swine ANP32A provides susceptibility to avian influenza virus infection in pigs.

Both the replication and transcription of the influenza virus are catalyzed by the viral polymerase complex. The polymerases of most avian influenza A viruses have poor performance in mammalian cells, which is considered to be one of the important species barriers. Pigs have been long considered as important intermediate hosts for interspecies transmission of the avian influenza virus, because of their susceptibility to infection with both avian and mammalian influenza viruses. However, the molecular basis of influenza polymerase adaptation in pigs remains largely unknown. ANP32A and ANP32B proteins have been identified as playing fundamental roles in influenza virus replication and host range determination. In this study, we found that swine ANP32A (swANP32A), unlike swine ANP32B or other mammalian ANP32A or B, shows stronger supporting activity to avian viral polymerase. Knockout of ANP32A in pig cells PK15 dramatically reduced avian influenza polymerase activity and viral infectivity, suggesting a unique feature of swANP32A in supporting avian influenza viral polymerase. This species-specific activity is mapped to two key sites, 106V and 156S, in swANP32A. Interestingly, the amino acid 106V is unique to pigs among all the vertebrate species studied, and when combined with 156S, exhibits positive epistasis in pigs. Mutation of 106V and 156S to the signature found in ANP32As from other mammalian species weakened the interaction between swANP32A and chicken viral polymerase, and reduced polymerase activity. Understanding the molecular basis of ANP32 proteins may help to discover new antiviral targets and design avian influenza resistant genome edited pigs.

Host-Virus Arms Races Drive Elevated Adaptive Evolution in Viral Receptors.

Viral receptors are the cell surface proteins that are hijacked by viruses to initialize their infections. Viral receptors are subject to two conflicting directional forces, namely, negative selection due to functional constraints and positive selection due to host-virus arms races. It remains largely obscure whether negative pleiotropy limits the rate of adaptation in viral receptors. Here, we perform evolutionary analyses of 96 viral receptor genes in primates and find that 41 out of 96 viral receptors experienced adaptive evolution. Many positively selected residues in viral receptors are located at the virus-receptor interfaces. Compared with control proteins, viral receptors exhibit significantly elevated rate of adaptation. Further analyses of genetic polymorphisms in human populations reveal signals of positive selection and balancing selection for 53 and 5 viral receptors, respectively. Moreover, we find that 49 viral receptors experienced different selection pressures in different human populations, indicating that viruses represent an important driver of local adaptation in humans. Our findings suggest that diverse viruses, many of which have not been known to infect nonhuman primates, have maintained antagonistic associations with primates for millions of years, and the host-virus conflicts drive accelerated adaptive evolution in viral receptors.IMPORTANCE Viruses hijack cellular proteins, termed viral receptors, to assist their entry into host cells. While viral receptors experience negative selection to maintain their normal functions, they also undergo positive selection due to an everlasting evolutionary arms race between viruses and hosts. A complete picture on how viral receptors evolve under two conflicting forces is still lacking. In this study, we systematically analyzed the evolution of 96 viral receptors in primates and human populations. We found around half of viral receptors underwent adaptive evolution and exhibit significantly elevated rates of adaptation compared to control genes in primates. We also found signals of past natural selection for 58 viral receptors in human populations. Interestingly, 49 viral receptors experienced different selection pressures in different human populations, indicating that viruses represent an important driver of local adaptation in humans. Our results suggest that host-virus arms races drive accelerated adaptive evolution in viral receptors.

Transcriptome Profiles of the Liver in Two Cold-Exposed Sheep Breeds Revealed Different Mechanisms and Candidate Genes for Thermogenesis.

Cold-induced thermogenesis plays an important role in the survival of lambs exposed to low air temperatures. The liver produces and mediates heat production in mammals; however, to date, little is known about the role of liver genes in cold-induced thermogenesis in lambs. In this study, the difference in the liver transcriptome between Altay and Hu ewe lambs was compared. Because of different backgrounds of the two breeds, we hypothesized that the transcriptome profiles of the liver would differ between breeds when exposed to cold. Cold-exposed Altay lambs activated 8 candidate genes (ACTA1, MYH1, MYH2, MYL1, MYL2, TNNC1, TNNC2, and TNNT3) involved in muscle shivering thermogenesis; 3 candidate genes (ATP2A1, SLN, and CKM) involved in muscle nonshivering thermogenesis related to the Ca2+ signal and creatine cycle; and 6 candidate genes (PFKM, ALDOC, PGAM2, ENO2, ENO3, and ENO4) involved in enhancing liver metabolism. In contrast, the liver may not act as the main tissue for thermogenesis in cold-exposed Hu lambs. We concluded that Altay lambs rely on liver-mediated shivering and nonshivering thermogenesis by muscle tissue to a greater extent than Hu lambs. Results from this study could provide a theoretical foundation for the breeding and production of cold-resistant lambs.

Elucidating the Phase Transformation and Metallization Behavior of Zinc Phosphide under High Pressure.

Among the family of II3V2-type compounds, zinc phosphide (Zn3P2) occupies a unique position. As one of the most promising semiconductors well-suited for photovoltaic applications, Zn3P2 has attracted considerable attention. The stability of its structure and properties are of great interest and importance for science and technology. Here, we systematically investigate the pressurized behavior of Zn3P2 using in situ synchrotron radiation angle-dispersive X-ray diffraction (ADXRD) and in situ electrical resistance measurement under high pressure. The ADXRD experiment shows that Zn3P2 undergoes an irreversible structural phase transition under high pressure, beginning at 11.0 GPa and being completed at ∼17.7 GPa. Consistently, the high-pressure electrical resistance measurement reveals a pressure-induced semiconductor-metal transition for Zn3P2 near 11.0 GPa. The kinetics of the phase transition is also studied using in situ electrical resistance measurement and can be well described by the classical Avrami model. What's more, the new high-pressure structure of Zn3P2 is refined to be orthorhombic with space group Pmmn; the lattice parameters and bulk modulus of this high-pressure phase are determined as a = 3.546 Å, b = 5.004 Å, c = 3.167 Å, and B0 = 126.3 GPa. Interestingly, we also predict a possible structural phase transformation of orthorhombic phase (Pmmn) to cubic phase (P4232) during the decompression process; this cubic Zn3P2 is metastable at ambient conditions. These experimental results reveal the unexpected high-pressure structural behaviors and electrical properties of Zn3P2, which could help to promote the further understanding and the future applications of Zn3P2 as well as other II3V2 compounds.