Selective sweep analysis of the adaptability of the Yarkand hare (Lepus yarkandensis) to hot arid environments using SLAF-seq.

The Yarkand hare (Lepus yarkandensis) inhabits arid desert areas and is endemic to China. It has evolved various adaptations to survive in hot arid environments, including stress responses, the ability to maintain water homeostasis and heat tolerance. Here, we performed a selective sweep analysis to identify the candidate genes for adaptation to hot arid environments in the Yarkand hare. A total of 397 237 single-nucleotide polymorphisms were obtained from 80 Yarkand hares, which inhabit hot arid environments, and 36 Tolai hares (Lepus tolai), which inhabit environments with a mild climate, via specific-locus amplified fragment sequencing. We identified several candidate genes that were associated with the heat stress response (HSPE1), oxidative stress response (SLC23A and GLRX2), immune response (IL1R1 and IRG1), central nervous system development (FGF13, THOC2, FMR1 and MECP2) and regulation of water homeostasis (CDK1) according to fixation index values and θπ ratios in the selective sweep analysis, and six of these genes (GLRX2, IRG1, FGF13, FMR1, MECP2 and CDK1) are newly discovered genes. To the best of our knowledge, this is the first study to identify candidate genes for adaptation to hot arid environments in the Yarkand hare. The results of this study enhance our understanding of the adaptation of the Yarkand hare to hot arid environments and will aid future studies aiming to functionally verify these candidate genes.

Corrigendum: Population genetics analysis of Tolai hares (Lepus tolai) in Xinjiang, China using genome-wide SNPs from SLAF-seq and mitochondrial markers.

[This corrects the article DOI: 10.3389/fgene.2022.1018632.].

A Polysiloxane Delivery Vehicle of Cyclic N-Halamine for Biocidal Coating of Cellulose in Supercritical CO2.

Cyclic N-halamines are highly antimicrobial, very stable, and not susceptible to bacterial resistance. A polysiloxane delivery vehicle was synthesized to deliver cyclic imide N-halamine onto cellulose via a benign and universal procedure that does not require a harmful solvent or chemical bonding. In brief, Knoevenagel condensation between barbituric acid and 4-hydroxybenzaldehyde furnished 5-(4-hydroxybenzylidene)pyrimidine-2,4,6-trione, whose phenolic O-H was subsequently reacted with the Si-H of poly(methylhydrosiloxane) (PMHS) via silane alcoholysis. The product of silane alcoholysis was interpenetrated into cellulose in supercritical CO2 (scCO2) at 50 °C, to form a continuous modification layer. The thickness of the modification layer positively correlated with interpenetration pressure in the experimental range of 10 to 28 MPa and reached a maximum value of 76.5 nm, which demonstrates the ability for tunable delivery, to control the loading of the imide N-H bond originating from barbituric acid unit. The imide N-H bonds on cellulose with the thickest modifier were then chlorinated into N-Cl counterparts using tert-butyl hypochlorite, to exert a powerful biocidability, providing ~7 log reductions of both S. aureus and E. coli in 20 min. The stability and rechargeability of the biocidability were both very promising, suggesting that the polysiloxane modifier has a satisfactory chemical structure and interlocks firmly with cellulose via scCO2 interpenetration.

Transcriptome analysis of pika heart tissue reveals mechanisms underlying the adaptation of a keystone species on the roof of the world.

High-altitude environments impose intense stresses on living organisms and drive striking phenotypic and genetic adaptations, such as hypoxia resistance, cold tolerance, and increases in metabolic capacity and body mass. As one of the most successful and dominant mammals on the Qinghai-Tibetan Plateau (QHTP), the plateau pika (Ochotona curzoniae) has adapted to the extreme environments of the highest altitudes of this region and exhibits tolerance to cold and hypoxia, in contrast to closely related species that inhabit the peripheral alpine bush or forests. To explore the potential genetic mechanisms underlying the adaptation of O. curzoniae to a high-altitude environment, we sequenced the heart tissue transcriptomes of adult plateau pikas (comparing specimens from sites at two different altitudes) and Gansu pikas (O. cansus). Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were used to identify differentially expressed genes (DEGs) and their primary functions. Key genes and pathways related to high-altitude adaptation were identified. In addition to the biological processes of signal transduction, energy metabolism and material transport, the identified plateau pika genes were mainly enriched in biological pathways such as the negative regulation of smooth muscle cell proliferation, the apoptosis signalling pathway, the cellular response to DNA damage stimulus, and ossification involved in bone maturation and heart development. Our results showed that the plateau pika has adapted to the extreme environments of the QHTP via protection against cardiomyopathy, tissue structure alterations and improvements in the blood circulation system and energy metabolism. These adaptations shed light on how pikas thrive on the roof of the world.

Population genetics analysis of Tolai hares (Lepus tolai) in Xinjiang, China using genome-wide SNPs from SLAF-seq and mitochondrial markers.

The main topic of population genetics and evolutionary biology is the influence of the ecological environment, geographical isolation, and climatic factors on population structure and history. Here, we estimated the genetic diversity, genetic structure, and population history of two subspecies of Tolai hares (Lepus tolai Pallas, 1778), L. t. lehmanni inhabiting Northern and Northwest Xinjiang and L. t. centrasiaticus inhabiting Central and Eastern Xinjiang using SNP of specific-length amplified fragment sequencing (SLAF-seq) and four mitochondrial DNA (mtDNA). Our results showed a relatively high degree of genetic diversity for Tolai hares, and the diversity of L. t. lehmanni was slightly higher than that of L. t. centrasiaticus, likely due to the more favorable ecological environment, such as woodlands and plains. Phylogenetic analysis from SNP and mtDNA indicated a rough phylogeographical distribution pattern among Tolai hares. Strong differentiation was found between the two subspecies and the two geographical groups in L. t. centrasiaticus, possibly due to the geographical isolation of mountains, basins, and deserts. However, gene flow was also detected between the two subspecies, which might be attributed to the Tianshan Corridor and the strong migration ability of hares. Tolai hare population differentiation occurred at approximately 1.2377 MYA. Population history analysis based on SNP and mtDNA showed that the Tolai hare population has a complex history and L. t. lehmanni was less affected by the glacial event, possibly because its geographic location and terrain conditions weaken the drastic climate fluctuations. In conclusion, our results indicated that the joint effect of ecological environment, geographic events, and climatic factors might play important roles in the evolutionary process of L. t. lehmanni and L. t. centrasiaticus, thus resulting in differentiation, gene exchange, and different population history.

Revealing the coexistence of differentiation and communication in an endemic hare, Lepus yarkandensis (Mammalia, Leporidae) using specific-length amplified fragment sequencing.

BACKGROUND: The Yarkand hare (Lepus yarkandensis Günther, 1875) is endemic to oasis and desert areas around the Tarim Basin in the Xinjiang Uyghur Autonomous Region of northwest China; however, genome-wide information for this species remains limited. Moreover, the genetic variation, genetic structure, and phylogenetic relationships of Yarkand hare from the plateau mountain regions have not been reported. Thus, we used specific-length amplified fragment sequencing (SLAF-seq) technology to evaluate the genetic diversity of 76 Yarkand hares from seven geographic populations in the northern and southwestern parts of the Tarim Basin to investigate single-nucleotide polymorphism (SNP) marker-based population differentiation and evolutionary processes. Selective sweep analysis was conducted to identify genetic differences between populations. RESULTS: Using SLAF-seq, a total of 1,835,504 SNPs were initially obtained, of which 308,942 high-confidence SNPs were selected for further analysis. Yarkand hares exhibited a relatively high degree of genetic diversity at the SNP level. Based on pairwise FST estimates, the north and southwest groups showed a moderate level of genetic differentiation. Phylogenetic tree and population structure analyses demonstrated evident systematic phylogeographical structure patterns consistent with the geographical distribution of the hares. Hierarchical analysis of molecular variation further indicated that genetic variation was mainly observed within populations. Low to moderate genetic differentiation also occurred among populations despite a common genomic background, likely due to geographical barriers, genetic drift, and differential selection pressure of distinct environments. Nevertheless, the observed lineage-mixing pattern, as indicated by the evolutionary tree, principal component analysis, population structure, and TreeMix analyses, suggests a certain degree of gene flow between the north and southwest groups. This may be related to the migration of hares to high-altitude water sources southwest of the basin during glacial climatic oscillations, as well as river re-diffusion and oasis restoration in the basin following the glacial period. We also identified candidate genes, and their associated gene ontology terms and pathways, related to the adaptation of Yarkand hares to different environmental habitats. CONCLUSIONS: The identified genome-wide SNPs, genetic diversity, and population structure of Yarkand hares expand our understanding of the genetic background of this endemic species and provide valuable insights into its environmental adaptation, allowing for further exploration of the underlying mechanisms.

Complete mitochondrial genome sequence of Lepus yarkandensis Günther, 1875 (Lagomorpha, Leporidae): characterization and phylogenetic analysis.

Lepus yarkandensis is a national second-class protected animal endemic to China and distributed only in the hot and arid Tarim Basin in Xinjiang. We sequenced and described the complete mitogenome of L. yarkandensis to analyze its characteristics and phylogeny. The species' DNA is a 17,047 bp circular molecule that includes 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes, and one control region. The overall base composition was as follows: A, 31.50%; T, 29.40%; G, 13.30% and C, 25.80%, with a high A+T bias of 60.9%. In the PCGs, ND6 had deviation ranges for AT skew (-0.303) and GC skew (0.636). The Ka/Ks values of ND1 (1.067) and ND6 (1.352) genes were >1, indicating positive selection, which might play an important role in the adaptation of L. yarkandensis to arid and hot environments. The conserved sequence block, the central conserved domain, and the extended termination-associated sequences of the control region and their features were identified and described. The phylogenetic tree based on the complete mitogenome showed that L. yarkandensis was closely related to the sympatric Lepus tibetanus pamirensis. These novel datasets of L. yarkandensis can supply basic data for phylogenetic studies of Lepus spp., apart from providing essential and important resource for further genetic research and the protection of this species.

L-proline-based deep eutectic solvents (DESs) for deep catalytic oxidative desulfurization (ODS) of diesel.

A series of L-proline-based DESs was prepared through an atom economic reaction between L-proline (L-Pro) and four different kinds of organic acids. The DESs were characterized by Fourier transform infrared spectroscopy (FT-IR), H nuclear magnetic resonance (1HNMR), cyclic voltammogram (CV) and the Hammett method. The synthesized DESs were used for the oxidative desulfurization and the L-Pro/p-toluenesultonic acid (L-Pro/p-TsOH) system shows the highest catalytic activity that the removal of dibenzothiophene (DBT) reached 99% at 60°C in 2h, which may involve the dual activation of the L-Pro/p-TsOH. The acidity of four different L-proline-based DESs was measured and the results show that it could not simply conclude that the correlation between the acidity of DESs and desulfurization capability was positive or negative. The electrochemical measurements evidences and recycling experiment indicate a good stability performance of L-Pro/p-TsOH in desulfurization. This work will provide a novel and potential method for the deep oxidation desulfurization.

The complete mitochondrial DNA sequence of the cape hare Lepus capensis pamirensis.

Lepus capensis pamirensis is a specific cape hare species that is only distributed in the Pamirs, with a cruel natural environment. The complete mitochondrial genome of the cape hare L. c. pamirensis was first determined (accession number LC073697), in a total length of 17 597 nucleotides, of which 15 310 nucleotides are coding DNA and 2287 nucleotides are non-coding DNA. It has the common feature with those of other hares with respect to genome structure and gene arrangement. It contained 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer tRNA genes and 1 control region (D-loop region). The complete mitochondrial genome of the cape hare L. c. pamirensis provides an important data set for further study on its classification.

Paternal and maternal genetic analysis of a desert Keriyan population: Keriyans are not the descendants of Guge Tibetans.

The Keriyan people live in an isolated village in the Taklimakan Desert in Xinjiang, Western China. The origin and migration of the Keriyans remains unclear. We studied paternal and maternal genetic variance through typing Y-STR loci and sequencing the complete control region of the mtDNA and compared them with other adjacent populations. Data show that the Keriyan have relatively low genetic diversity on both the paternal and maternal lineages and possess both European and Asian specific haplogroups, indicating Keriyan is an admixture population of West and East. There is a gender-bias in the extent of contribution from Europe vs. Asia to the Keriyan gene pool. Keriyans have more genetic affinity to Uyghurs than to Tibetans. The Keriyan are not the descendants of the Guge Tibetans.

Genetic polymorphism of 17 Y chromosomal STRs in Kazakh and Uighur populations from Xinjiang, China.

To evaluate the utility of Y-STR data for DNA testing in two ethnic populations of Xinjiang province, a sample of 338 subjects (121 Kazakhs and 217 Uighurs) was tested. In the Kazakh and Uighur populations, the haplotype diversity was 0.868 and 0.996, respectively, and the discrimination capacity was 0.5950 and 0.8940, respectively. High numbers of singleton haplotypes were observed among Xinjiang Uighurs, but fewer were found in Kazakhs. Our results were also compared with geographically and linguistically close populations.

Genetic diversities of cytochrome B in Xinjiang Uyghur unveiled its origin and migration history.

BACKGROUND: Uyghurs are one of the many populations of Central Eurasia that is considered to be genetically related to Eastern and Western Eurasian populations. However, there are some different opinions on the relative importance of the degree of Eastern and Western Eurasian genetic influence. In addition, the genetic diversity of the Uyghur in different geographic locations has not been clearly studied. RESULTS: In this study, we are the first to report on the DNA polymorphism of cytochrome B in the Uyghur population located in Xinjiang in northwest China. We observed a total of 102 mutant sites in the 240 samples that were studied. The average number of mutated nucleotides in the samples was 5.126. A total of 93 different haplotypes were observed. The gene diversity and discrimination power were 0.9480 and 0.9440, respectively. There were founder and bottleneck haplotypes observed in Xinjiang Uyghurs. Xinjiang Uyghurs are more genetically related to Chinese population in genetics than to Caucasians. Moreover, there was genetic diversity between Uyghurs from the southern and northern regions. There was significance in genetic distance between the southern Xinjiang Uyghurs and Chinese population, but not between the northern Xinjiang Uyghurs and Chinese. The European vs. East Asian contribution to the ten regional Uyghur groups varies among the groups and the European contribution to the Uyghur increases from north to south geographically. CONCLUSION: This study is the first report on DNA polymorphisms of cytochrome B in the Uyghur population. The study also further confirms that there are significant genetic differences among the Uyghurs in different geographical locations.

[Genetic structure and subspecies divergence of Lepus capensis in Xinjiang].

To date, the genetic structure and genetic diversity of Lepus capensis in Xinjiang has not been systematically studied at the molecular level, and its subspecies taxonomic status has been under debate for years. According to traditional morphology, there are three subspecies of L. capensis distributed in Xinjiang: L.c. centrasiaticus, L.c. lehmanni and L.c. pamirensis. In this study, we determined 592 bp D-loop sequences of 87 cape hares from Xinjiang Province. Forty-four haplotypes were defined based on 148 polymorphic sites. Both the haplotype diversity (0.977+/-0.005) and nucleotide diversity (0.064+/-0.031) are high. FST P values are significantly high and no haplotype was shared among the four geographic populations, indicating that genetic differentiation among populations is significant. AMOVA shows that most of the genetic differentiation occurred among geographic groups, indicating that geographic isolation such as mountains and deserts might make an effective barrier against gene flow. Both the phylogenetic tree and median-joining network grouped 44 haplotypes into four distinct clades corresponding to four geographic areas, indicating an obvious phylogeographic pattern. Our data supported the subspecies status of L. c. lehmanni. The fact that haplotypes of L. c. centrasiaticus were grouped into two distinct clades suggests that this traditional subspecies should be considered as two subspecies. In addition, L. c. pamirensis shows a significantly higher sequence divergence compared to other subspecies, and the difference even reached the level of species.

[Comparison of statistical methods for detecting differential expression in microarray data].

DNA microarray is a new tool in biotechnology, which allows simultaneously monitoring thousands of gene expression in cells. The goal of differential gene expression analysis is to detect genes with significant change of gene expression levels arising from experimental conditions. Although various statistical methods have been suggested to confirm differential gene expression, only a few studies compared performance of the statistical methods. This paper presented comparison of statistical methods for finding differentially expressed genes (DEGs) from the microarray data. Using simulated and real datasets (Populus cDNA microarray data), we compared eight methods of identifying differential gene expression. The simulated datasets included four differential distributions (normal distribution, uniform distribution, c2 distribution, and exponential distribution). The results of simulated datasets analysis showed that the eight methods were more preferable with the microarray data of uniform distribution than normal distribution. They were not preferable with the c2 distribution and exponential distribution. Of these eight methods, SAM (Significance Analysis of Microarrays) and Wilcoxon rank sum test performed well in most cases. The results of real cDNA microarray data of Populus showed that there was much similarity of SAM, Samroc, and regression modeling approach. Wilcoxon rank sum test was different from them. Samroc and regression modeling approach were similar in the eight methods. For both simulated and real datasets, SAM, Samroc, and regression modeling approach performed better than other methods.

[Expression of FMDV VP1 protein in Pichia pastoris and its immunological activity in mice].

AIM: To express and identify bovine O type foot and mouth disease virus protein 1 (FMDV VP1) in yeast Pichia pastoris. METHODS: FMDV vp1 gene was cloned into secretory Pichia pastoris expression vector-pSuperY. After being linearized with enzyme digestion, the vector was transformed into Pichia pastoris SMD1168H by electroporation. The transformant was screened by zeocin. Expressed proteins in yeast were analyzed by SDS-PAGE and Western blot and then were used to immunize mice. RESULTS: The results of SDS-PAGE and Western blot demonstrated that the culture supernatant of recombinant yeast contained VP1 protein. The recombinant VP1 protein could elicit similar humoral and cellular immune responses in mice to traditional FMDV killed vaccine. CONCLUSION: FMDV VP1 is expressed successfully in yeast Pichia pastoris, which lays the foundation for further FMDV vaccine research.

[Using single primer PCR to amplify the orf25 gene fragment related to plant male-sterility in Salicornia europaea].

The gene orf25 encodes functional protein that may play an important role in plant fertility control in nature. To clone the orf25 from Salicornia europaea Xinjiang into a T-vector, a single designed primer was used to amplify 1.7kb cDNA fragment with RT-PCR. Sequence analysis reveals that the cloned fragment contains entire orf25 coding region with 98%, 95%, 92% and 88% identity to that of orf25 from Beta vulgaris, Nicotiana, wheat and maize mitochondrion, respectively. This analysis suggests that orf25 gene is highly conserved in terms of evolution in plant; and it also suggests that wild plant Salicornia europaea contain a male-sterility gene similar to crops that is of great importance in improvement of the breed of crop.