Genome-wide association study, population structure, and genetic diversity of the tea plant in Guizhou Plateau.

BACKGROUND: Guizhou Plateau, as one of the original centers of tea plant, has a profound multi-ethnic cultural heritage and abundant tea germplasm resources. However, the impact of indigenous community factors on the genetic diversity, population structure and geographical distribution of tea plant is still unclear. RESULTS: Using the genotyping-by-sequencing (GBS) approach, we collected 415 tea plant accessions from the study sites, estimated genetic diversity, developed a core collection, and conducted a genome-wide association study (GWAS) based on 99,363 high-quality single-nucleotide polymorphisms (SNPs). A total of 415 tea accessions were clustered into six populations (GP01, GP02, GP03, GP04, GP05 and GP06), and the results showed that GP04 and GP05 had the highest and lowest genetic diversity (Pi = 0.214 and Pi = 0.145, respectively). Moreover, 136 tea accessions (33%) were selected to construct the core set that can represent the genetic diversity of the whole collection. By analyzing seven significant SNP markers associated with the traits such as the germination period of one bud and two leaves (OTL) and the germination period of one bud and three leaves (OtL), four candidate genes possibly related to OTL and OtL were identified. CONCLUSIONS: This study revealed the impact of indigenous communities on the population structure of 415 tea accessions, indicating the importance of cultural practices for protection and utilization of tea plant genetic resources. Four potential candidate genes associated with the OTL and OtL of tea plant were also identified, which will facilitate genetic research, germplasm conservation, and breeding.

Analysis of population structure and genetic diversity of Camellia tachangensis in Guizhou based on SNP markers.

BACKGROUND: Camellia tachangensis F. C. Zhang is a five-compartment species in the ovary of tea group plants, which represents the original germline of early differentiation of some tea group plants. METHODS AND RESULTS: In this study, we analyzed single-nucleotide polymorphisms (SNPs) at the genome level, constructed a phylogenetic tree, analyzed the genetic diversity, and further investigated the population structure of 100 C. tachangensis accessions using the genotyping-by-sequencing (GBS) method. A total of 91,959 high-quality SNPs were obtained. Population structure analysis showed that the 100 C. tachangensis accessions clustered into three groups: YQ-1 (Village Group), YQ-2 (Forest Group) and YQ-3 (Transition Group), which was further consistent with the results of phylogenetic analysis and principal component analyses (PCA). In addition, a comparative analysis of the genetic diversity among the three populations (Forest, Village, and Transition Groups) detected the highest genetic diversity in the Transition Group and the highest differentiation between Forest and Village Groups. CONCLUSIONS: C. tachangensis plants growing in the forest had different genetic backgrounds from those growing in villages. This study provides a basis for the effective protection and utilization of C. tachangensis populations and lays a foundation for future C. tachangensis breeding.

The evolution and expansion of RWP-RK gene family improve the heat adaptability of elephant grass (Pennisetum purpureum Schum.).

BACKGROUND: Along with global warming, resulting in crop production, exacerbating the global food crisis. Therefore, it is urgent to study the mechanism of plant heat resistance. However, crop resistance genes were lost due to long-term artificial domestication. By analyzing the potential heat tolerance genes and molecular mechanisms in other wild materials, more genetic resources can be provided for improving the heat tolerance of crops. Elephant grass (Pennisetum purpureum Schum.) has strong adaptability to heat stress and contains abundant heat-resistant gene resources. RESULTS: Through sequence structure analysis, a total of 36 RWP-RK members were identified in elephant grass. Functional analysis revealed their close association with heat stress. Four randomly selected RKDs (RKD1.1, RKD4.3, RKD6.6, and RKD8.1) were analyzed for expression, and the results showed upregulation under high temperature conditions, suggesting their active role in response to heat stress. The members of RWP-RK gene family (36 genes) in elephant grass were 2.4 times higher than that of related tropical crops, rice (15 genes) and sorghum (15 genes). The 36 RWPs of elephant grass contain 15 NLPs and 21 RKDs, and 73% of RWPs are related to WGD. Among them, combined with the DAP-seq results, it was found that RWP-RK gene family expansion could improve the heat adaptability of elephant grass by enhancing nitrogen use efficiency and peroxidase gene expression. CONCLUSIONS: RWP-RK gene family expansion in elephant grass is closely related to thermal adaptation evolution and speciation. The RKD subgroup showed a higher responsiveness than the NLP subgroup when exposed to high temperature stress. The promoter region of the RKD subgroup contains a significant number of MeJA and ABA responsive elements, which may contribute to their positive response to heat stress. These results provided a scientific basis for analyzing the heat adaptation mechanism of elephant grass and improving the heat tolerance of other crops.

Milletdb: a multi-omics database to accelerate the research of functional genomics and molecular breeding of millets.

Millets are a class of nutrient-rich coarse cereals with high resistance to abiotic stress; thus, they guarantee food security for people living in areas with extreme climatic conditions and provide stress-related genetic resources for other crops. However, no platform is available to provide a comprehensive and systematic multi-omics analysis for millets, which seriously hinders the mining of stress-related genes and the molecular breeding of millets. Here, a free, web-accessible, user-friendly millets multi-omics database platform (Milletdb, http://milletdb.novogene.com) has been developed. The Milletdb contains six millets and their one related species genomes, graph-based pan-genomics of pearl millet, and stress-related multi-omics data, which enable Milletdb to be the most complete millets multi-omics database available. We stored GWAS (genome-wide association study) results of 20 yield-related trait data obtained under three environmental conditions [field (no stress), early drought and late drought] for 2 years in the database, allowing users to identify stress-related genes that support yield improvement. Milletdb can simplify the functional genomics analysis of millets by providing users with 20 different tools (e.g., 'Gene mapping', 'Co-expression', 'KEGG/GO Enrichment' analysis, etc.). On the Milletdb platform, a gene PMA1G03779.1 was identified through 'GWAS', which has the potential to modulate yield and respond to different environmental stresses. Using the tools provided by Milletdb, we found that the stress-related PLATZs TFs (transcription factors) family expands in 87.5% of millet accessions and contributes to vegetative growth and abiotic stress responses. Milletdb can effectively serve researchers in the mining of key genes, genome editing and molecular breeding of millets.

2,4-Dichlorophenol Increases Primordial Germ Cell Numbers via ESR2a-Dependent Pathway in Zebrafish Larvae.

Previous studies have reported the feminizing effects of 2,4-dichlorophenol (2,4-DCP) on zebrafish (Danio rerio). However, the effect of 2,4-DCP on the number of primordial germ cells (PGCs), an indicator for early sex differentiation, remains elusive. In the present study, Tg (piwil1:egfp-UTR nanos3) zebrafish (GFP-labeled PGCs) were treated with 2,4-DCP (10, 20, and 40 µg/L) from 5 to 15 days postfertilization to explore the effect on PGC numbers and to elucidate associated molecular mechanisms. The results showed that 2,4-DCP exposure increased PGC numbers, as evidenced by larger GFP fluorescent areas, upregulated expressions of PGC marker genes (vasa and dnd), and raised the female ratio. Notably, the mRNA level of estrogen receptor 2a (esr2a) was also increased subsequently. Moreover, docking studies revealed stable 2,4-DCP interactions with ESR2a, speculating a role of ESR2a signaling pathway in 2,4-DCP toxicity. Furthermore, in esr2a knockout (esr2a-/-) zebrafish, the effects of 2,4-DCP were considerably minimized, proving the involvement of the ESR2a signaling pathway in the 2,4-DCP-mediated increase in PGC numbers. Dual-luciferase reporter gene assay and point mutation studies demonstrated that 2,4-DCP-stimulated promoter activity was mediated by estrogen response element (ERE) located in -686/-674 of the vasa promoter and -731/-719 of the dnd promoter. Overall, 2,4-DCP can potentially enhance the expression of vasa and dnd by binding to zebrafish ESR2a, thus leading to increased PGC numbers and subsequent female-biased sex differentiation.

Nitrogen-Doped MoS2/Ti3C2TX Heterostructures as Ultra-Efficient Alkaline HER Electrocatalysts.

Molybdenum disulfide (MoS2) is intrinsically inert for the hydrogen evolution reaction (HER) in alkaline media due to its electronic structures. Herein, we tune the electronic structures of MoS2 by a combined strategy of post-N doping coupled with the synergistic effect of Ti3C2TX. The as-prepared N-doped MoS2/Ti3C2TX heterostructures show remarkable alkaline HER activity with an overpotential of 225 mV at 140 mA cm-2, which ranks the N-doped MoS2/Ti3C2TX heterostructures among the best MoS2/MXene-based electrocatalysts reported for alkaline HER. The first-principles calculations indicate that the N doping can enhance the activation of nearby S sites of MoS2/Ti3C2TX and thus promote the HER process. This strategy provides a promising way to develop high-efficiency MoS2/MXene heterostructure catalysts for alkaline HER.

Low-dose cadmium exposure facilitates cell proliferation by promoter hypermethylation of RASSF1A and DAPK1 genes.

Cadmium (Cd) at low concentrations has a potential to promote cell proliferation. However, the molecular mechanisms of Cd-induced proliferation are not well understood. Here, we reported that Cd (0-500 nM) significantly promoted the proliferation of HepG2 cells as demonstrated by elevated cell viability, more EdU-positive cells and increased gene expression of KI-67 and COX-2. Meanwhile, the gene expression of DNA methyltransferases was found to be elevated while that of tumor suppressor genes DAPK1 and RASSF1A were decreased under Cd exposure. Correspondingly, the methylation level of promoters in DAPK1 and RASSF1A were increased. Specifically, the CpG sites at -461 (Chr3:50, 374, 481) of RASSF1A promoter, and that at -260 (Chr9:90, 113, 207), -239 (Chr9:90, 113, 228), and -68 (Chr9:90, 113, 399) of DAPK1 promoter, were significantly hypermethylated. Moreover, 5-azacytidine (an inhibitor of DNA methyltransferase) partly impaired Cd-induced promoter hypermethylation of RASSF1A and DAPK1 genes, increased their expressions and slowed down Cd-induced cell proliferation, suggesting that DNA methylation play an essential part in Cd-boosted proliferation. The study showed that Cd caused promoter hypermethylation of RASSF1A and DAPK1, decreasing their expression and leading to higher level of cell proliferation. Furthermore, Cd at low concentrations could influence DNA methylation, which may serve as the proliferative mechanism of Cd.

High temperature induced masculinization of zebrafish by down-regulation of sox9b and esr1 via DNA methylation.

Elevated temperature could influence the sex differentiation by altering the expression of sex-related genes in fish. However, the underlying mechanisms by which the gene expression is altered remain poorly understood. Here, we aimed to explore the role of DNA methylation in sex differentiation of zebrafish (Danio rerio) in response to elevated temperature. The results showed that high temperature (33°C) exposure of fish from 20 to 30 days post fertilization (dpf), compared to normal temperature (28°C), resulted in male-biased sex ratio and decreased expression of female-related genes including cyp19a1a, sox9b and esr1. Meanwhile, the expressions of DNA methyltransferases dnmt3a1 and dnmt3a2, and the DNA methylation levels in sox9b and esr1 promoter were significantly increased by high temperature, strongly implying that DNA methylation is involved in high temperature-induced masculinization of zebrafish. Co-treatment with 5-aza-2'-deoxycytidine (a DNA methylation inhibitor) attenuated the high temperature-induced masculinizing effect, recovered the expression of esr1 and sox9b, suppressed the transcription of dnmt3a1 and dnmt3a2, and decreased the methylation of esr1 and sox9b promoter, further confirming that DNA methylation plays an important role in high temperature-induced masculinization of zebrafish. Furthermore, the methylation of sox9b promoter decreased the enrichment of transcription factor CREB (cAMP-responsive element binding proteins). Overall, these findings suggest that high temperature induce masculinization of zebrafish by down-regulation of female-related genes via DNA methylation, providing a new insight in understanding the epigenetic mechanism of thermal-mediated sex differentiation in fish.

Transcriptome analysis of heat stress and drought stress in pearl millet based on Pacbio full-length transcriptome sequencing.

BACKGROUND: Heat and drought are serious threats for crop growth and development. As the sixth largest cereal crop in the world, pearl millet can not only be used for food and forage but also as a source of bioenergy. Pearl millet is highly tolerant to heat and drought. Given this, it is considered an ideal crop to study plant stress tolerance and can be used to identify heat-resistant genes. RESULTS: In this study, we used Pacbio sequencing data as a reference sequence to analyze the Illumina data of pearl millet that had been subjected to heat and drought stress for 48 h. By summarizing previous studies, we found 26,299 new genes and 63,090 new transcripts, and the number of gene annotations increased by 20.18%. We identified 2792 transcription factors and 1223 transcriptional regulators. There were 318 TFs and 149 TRs differentially expressed under heat stress, and 315 TFs and 128 TRs were differentially expressed under drought stress. We used RNA sequencing to identify 6920 genes and 6484 genes differentially expressed under heat stress and drought stress, respectively. CONCLUSIONS: Through Pacbio sequencing, we have identified more new genes and new transcripts. On the other hand, comparing the differentially expressed genes under heat tolerance with the DEGs under drought stress, we found that even in the same pathway, pearl millet responds with a different protein.

Inheritance patterns of leukocyte gene expression under heat stress in F1 hybrid cattle and their parents.

Crossbreeding capitalizes on heterosis effects and results in increased performance of crossbred animals. Dominance hypothesis and overdominance hypothesis are 2 common models proposed to explain heterosis. Differential gene expression between parents and hybrids is hypothesized to be responsible for heterosis. This study aimed to investigate the heat tolerance and inheritance patterns of leukocyte transcriptomics in F1 hybrid cattle (Angus males × Droughtmaster females) and their parents Red Angus (AN) and Droughtmaster (DR) under heat stress. According to the respiratory rate and heat tolerance coefficient index, DR was better adapted to heat stress than AN. The physiological responses to heat stress of F1 hybrids were similar to AN. We identified 802 differentially expressed genes in leukocytes between AN and DR under heat stress using mRNA sequencing. Compared with AN, upregulated genes in DR were enriched in biological processes of response to stress, external and chemical stimulus, and cytokine, cell surface receptor signaling pathway, and cardiovascular system development. In contrast, upregulated genes in AN were enriched in B cell activation and regulation of B cell activation. Gene expression levels can be inherited additively or nonadditively and are classified into additive (35%), dominance (44%), and overdominance and underdominance (18%) modes in F1 hybrids and their parents. Inheritance patterns of gene expression showed that 97% (249/255) of the dominant genes were classified as paternal AN dominant in hybrids. The paternal imprinted PEG10 gene and its regulatory transcription factor MYC showed an AN dominant expression pattern. The MYC interacted with most AN dominant genes. These transcriptomic analyses revealed that DR and AN had specific cellular and humoral immunity and cardiovascular systems development function under heat stress. Inheritance pattern analyses from gene expression partly explained phenotypic differences between parents and F1 hybrids. The paternal imprinted PEG10 gene interaction with transcription factor MYC may contribute to explaining paternal dominant gene expression in hybrids.

2,4-Dichlorophenol induced feminization of zebrafish by down-regulating male-related genes through DNA methylation.

2,4-Dichlorophenol (2,4-DCP) is ubiquitous in aquatic environment and has potential estrogenic effect on fish. However, the effect of 2,4-DCP on sex differentiation of zebrafish (Danio rerio) and the underlying mechanism are largely unknown. To address these questions, zebrafish larvae at 20 or 30 days post fertilization (dpf) were exposed to 2,4-DCP (0, 80 and 160 µg L-1) with/without 5-aza-2'-deoxycytidine (5AZA, 50 µg L-1) for 10 days. The sex ratios and the expressions of male-related genes including amh, gata4, nr5a1a, nr5a2 and sox9a were analyzed. In addition, the DNA methylation levels of amh, nr5a2 and sox9a were examined. The results showed that 2,4-DCP exposure resulted in significant increase of female ratios both in 20-30 and 30-40 dpf groups. Correspondingly, the expressions of gata4, nr5a1a, nr5a2 and sox9a were decreased by 2,4-DCP exposure in two treatment periods. However, the transcript of amh was decreased by 2,4-DCP exposure only from 30 to 40 dpf. The DNA methylation levels of amh, nr5a2 and sox9a were increased following 2,4-DCP exposure. Moreover, the addition of 5AZA could counteract the effects including feminization, disturbance of gene expression and DNA hypermethylation caused by 2,4-DCP. These results indicated that the feminizing effect of 2,4-DCP was accomplished by regulating the expression of male-related genes through DNA methylation.

Effect of weaning age on growth performance, feed efficiency, nutrient digestibility and blood-biochemical parameters in Droughtmaster crossbred beef calves.

OBJECTIVE: The objective of this study was to determine the effect of weaning age on intake, performance, nutrition metabolism and serum parameters of beef calves. METHODS: Sixty Droughtmaster crossbred calves were assigned to 5 groups with 12 calves in each group. The calves in control group remained with the dams till the 22-week age, while the calves weaned at 28 d (4 wk), 42 d (6 wk), 56 d (8 wk), and 70 d (10 wk) of age were sent to group 4 wk, group 6 wk, group 8 wk, and group 10 wk, respectively, and then were fed on milk replacer till the 22-week age. Feed intake and body weight and size were record and blood metabolites were measured. And 24 calves of them (6 in each group) were picked randomly for digestion and metabolism trail. Feed, feces and urine sample were taken and measured. RESULTS: Dry matter intake of calves in group 4 wk was significantly lower than those in the remaining groups from wk 17 to 22 (p<0.05). Feed efficiency of the calves was higher in groups 4 wk and 6 wk than those in groups 8 wk and 10 wk from 11 to 13 wk (p<0.05), and calves had higher feed efficiency in group 4 wk, group 6 wk, and group 8 wk than those in group 10 wk from wk 14 to wk 22. Calves in group 4 wk and 6 wk had lower body weight than group 8 wk and group 10 wk and control group at 10-week age (p<0.05) and 13-week age (p<0.05), and calves in group 6 wk had no significant difference in body weight with control group, group 8 wk and 10 wk (p>0.05) but was higher than that of group 4 wk (p<0.05). Calves in group 6 wk had higher final body weight and total gain than group 4 wk, but no difference of total gain with that of groups 8 wk, 10 wk, and control group. And weaning calves at 6-week age brought higher feed efficiency and average daily gain from wk 14 to wk 22, and higher dry matter and organic matter digestibility at 21 wk. CONCLUSION: It is concluded that the weaning of calves at 6 weeks of age gave positive results.

2,4-dichlorophenol induces ER stress-mediated apoptosis via eIF2α dephosphorylation in vitro.

2,4-Dichlorophenol (2,4-DCP) has been widely used to produce herbicides and pharmaceutical intermediates, which exhibits various toxic effects including apoptosis. However, the mechanisms underlying 2,4-DCP-induced apoptosis, especially mediated by endoplasmic reticulum (ER) stress, are still unknown. In the present study, the mouse embryonic fibroblasts (MEFs) were used as an in vitro model system to figure out whether 2,4-DCP could induce ER stress, and further to elucidate the role of ER stress in 2,4-DCP-induced apoptosis. The results showed that 2,4-DCP dramatically caused the decrease of cell viability, the increase of apoptotic cells, the collapse of mitochondrial membrane potential (MMP) and the activation of caspase-3, suggesting that 2,4-DCP did induce apoptosis. Meanwhile, 2,4-DCP acted similarly as ER stress agonist tunicamycin (Tu) to activate all three branches (IRE1α, ATF6 and eIF2α) of ER stress. Furthermore, repression of ER stress or inhibition of eIF2α dephosphorylation significantly alleviated 2,4-DCP-induced apoptosis. Taking these results together, the present study firstly showed that 2,4-DCP induced ER stress-mediated apoptosis via eIF2α dephosphorylation in mammalian cells. These findings will provide new insights into the mechanisms underlying apoptosis after chlorophenols exposure.

2,4,6-Trichlorophenol cytotoxicity involves oxidative stress, endoplasmic reticulum stress, and apoptosis.

This study aims to evaluate the cytotoxicity and potential mechanisms of 2,4,6-trichlorophenol (2,4,6-TCP) in mouse embryonic fibroblasts. Our results show that 2,4,6-TCP causes morphological changes and reduces cell viability. The overproduction of reactive oxygen species, the upregulation of nuclear factor-E2-related factor 2 (Nrf2) and heme oxygenase 1 (HMOX1) messenger RNA (mRNA) expressions, and the nuclear translocation of Nrf2 protein demonstrate that 2,4,6-TCP induces oxidative stress, and the Nrf2/HMOX1 pathway might be involved in 2,4,6-TCP-induced antioxidative response. Simultaneously, our data also demonstrate that 2,4,6-TCP upregulates the expressions of binding immunoglobulin protein, inositol-requiring enzyme/endonuclease 1α, and C/EBP homologous protein; stimulates α subunit of eukaryotic translation initiation factor 2 phosphorylation; and induces the splicing of Xbp1 mRNA, suggesting that endoplasmic reticulum (ER) stress is triggered. Moreover, 2,4,6-TCP alters the mitochondrial membrane potential and increases the apoptosis rate, the caspase 3 activity, and the Bax/Bcl-2 ratio, demonstrating that the mitochondrial pathway is involved in the 2,4,6-TCP-induced apoptosis. Thus, these results show that 2,4,6-TCP induces oxidative stress, ER stress, and apoptosis, which together contribute to its cytotoxicity in vitro.

EGCG inhibits Cd(2+)-induced apoptosis through scavenging ROS rather than chelating Cd(2+) in HL-7702 cells.

CONTEXT AND OBJECTIVE: Epigallocatechin-3-gallat (EGCG), the major catechin in green tea, shows a potential protective effect against heavy metal toxicity to humans. Apoptosis is one of the key events in cadmium (Cd(2+))-induced cytotoxicity. Nevertheless, the study of EGCG on Cd(2+)-induced apoptosis is rarely reported. The objective of this study was to clarify the effect and detailed mechanism of EGCG on Cd(2+)-induced apoptosis. METHODS: Normal human liver cells (HL-7702) were treated with Cd(2+) for 21 h, and then co-treated with EGCG for 3 h. Cell viability, apoptosis, intracellular reactive oxygen species (ROS), malondialdehyde (MDA), mitochondrial membrane potential (MMP) and caspase-3 activity were detected. On the other hand, the chelation of Cd(2+) with EGCG was tested by UV-Vis spectroscopy analysis and Nuclear Magnetic Resonance ((1)H NMR) spectroscopy under neutral condition (pH 7.2). RESULTS AND CONCLUSION: Cd(2+) significantly decreased the cell viability and induced apoptosis in HL-7702 cells. Conversely, EGCG co-treatment resulted in significant inhibition of Cd(2+)-induced reduction of cell viability and apoptosis, implying a rescue effect of EGCG against Cd(2+) poisoning. The protective effect most likely arises from scavenging ROS and maintaining redox homeostasis, as the generation of intracellular ROS and MDA is significantly reduced by EGCG, which further prevents MMP collapse and suppresses caspase-3 activity. However, no evidence is observed for the chelation of EGCG with Cd(2+) under neutral condition. Therefore, a clear conclusion from this work can be made that EGCG could inhibit Cd(2+)-induced apoptosis by acting as a ROS scavenger rather than a metal chelating agent.

Cadmium induces mitophagy through ROS-mediated PINK1/Parkin pathway.

CONTEXT AND OBJECTIVE: Recent reports have highlighted the relationship between cadmium (Cd) and autophagy, however, whether Cd can activate mitophagy remains enigmatic. This study aims to investigate the effects of Cd on mitophagy and its potential mechanism. METHODS: Mice were intraperitoneally injected with Cd for 3 d. Mitochondrial membrane potential (MMP), mitophagosomes, LC3-II/LC3-I ratio, PINK1 level and mitochondrial mass were evaluated to indicate the effects of Cd on mitophagy. To elucidate the mechanism, reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) or acetyl-L-carnitine (ALC) as well as the mitophagy inhibitor cyclosporine A (CsA) were introduced to verify the role of ROS in mitophagy. RESULTS AND CONCLUSIONS: The results showed that Cd significantly induced MMP collapse and typical mitophagosomes formation, increased LC3-II/LC3-I ratio and PINK1 level, and decreased mitochondrial mass, revealing that Cd could induce mitophagy. However, NAC or ALC pretreatment markedly decreased Cd-induced ROS and simultaneously rescued MMP and mitochondrial mass, suggesting ROS played a crucial role in regulating mitophagy. NAC or ALC also dramatically lessened PINK1 level and mitochondrial accumulation of Parkin, indicating that ROS were related to PINK1/Parkin pathway. Notably, CsA compromised Cd-induced mitophagy, PINK1 accumulation and Parkin translocation while failed to block ROS increase, suggesting ROS functioned as an upstream signal for PINK1/Parkin pathway. Taken together, the results indicated that Cd induced ROS-mediated mitophagy through PINK1/Parkin pathway in kidneys of mice. The present study proposes a new perspective to evaluate the nephrotoxicity and its molecular mechanism under Cd exposure in vivo.

Polystyrene microplastics mitigate lead-induced neurotoxicity by reducing heavy metal uptake in zebrafish larvae.

The combined pollution of lead (Pb) and polystyrene microplastics (PS-MPs) is common in aquatic environments. However, the combined neurotoxicity of these two pollutants is still poorly understood. In this study, zebrafish (Danio rerio) larvae were used to assess the combined neurotoxicity and mechanism of Pb and PS-MPs at environmentally relevant concentrations. The results showed that Pb (10 µg/L) induced abnormal behavior including significantly reduced movement distance, maximum acceleration, and average velocity (P < 0.05) along with altered expression of neurodevelopment-related genes (gap43 and α1-tubulin) (P < 0.05). PS-MPs (25 µg/L, 250 µg/L; diameter at 25 µm) co-exposure not only significantly reduced the concentration of Pb in the exposed solution (P < 0.01), but also decreased the uptake of Pb by downregulating the divalent metal transporter 1 gene (dmt1) (P < 0.01), thereby alleviating Pb-induced neurotoxicity. However, to demonstrate that PS-MPs alleviate the neurotoxicity of Pb by reducing Pb uptake, upregulation of dmt1 by addition of deferoxamine (DFO, an efficient iron chelator, 100 µM) significantly increased the Pb uptake and exacerbated neurotoxicity in zebrafish. In summary, our results demonstrated that PS-MPs alleviate Pb neurotoxicity by downregulating the mRNA level of dmt1 and decreasing the Pb uptake. This study provides a new insight into the combined neurotoxicity and underlying mechanisms of PS-MPs and Pb on zebrafish.

γ-H2AX and other histone post-translational modifications in the clinic.

Chromatin is a dynamic complex of DNA and proteins that regulates the flow of information from genome to end product. The efficient recognition and faithful repair of DNA damage, particularly double-strand damage, is essential for genomic stability and cellular homeostasis. Imperfect repair of DNA double-strand breaks (DSBs) can lead to oncogenesis. The efficient repair of DSBs relies in part on the rapid formation of foci of phosphorylated histone H2AX (γ-H2AX) at each break site, and the subsequent recruitment of repair factors. These foci can be visualized with appropriate antibodies, enabling low levels of DSB damage to be measured in samples obtained from patients. Such measurements are proving useful to optimize treatments involving ionizing radiation, to assay in vivo the efficiency of various drugs to induce DNA damage, and to help diagnose patients with a variety of syndromes involving elevated levels of γ-H2AX. We will survey the state of the art of utilizing γ-H2AX in clinical settings. We will also discuss possibilities with other histone post-translational modifications. The ability to measure in vivo the responses of individual patients to particular drugs and/or radiation may help optimize treatments and improve patient care. This article is part of a Special Issue entitled: Chromatin in time and space.

Predicting the current and future distributions of Pennisetum alopecuroides (L.) in China under climate change based on the MaxEnt model.

Pennisetum alopecuroides (L.), one of the important exotic plants, gives great economic value to animal husbandry in China. In order to study the distribution of Pennisetum alopecuroides (L.) in China and its response to climate change, based on the distribution records of Pennisetum alopecuroides (L.), our study used the Maximum Entropy (MaxEnt) model and geographic information system (GIS) methods, combined with environmental factors such as climate and terrain, to predict the potential distribution areas suitable for Pennisetum alopecuroides (L.) under current and future climate scenarios. The results showed that annual precipitation was the most important factor affecting the distribution of Pennisetum alopecuroides (L.). In current climate scenario, the total area of suitable for Pennisetum alopecuroides (L.) growth was about 576.5 km2, accounting for about 60.5% of the total land area of China. Among all the suitable areas, the area of low, middle and high fitness areas accounted for 5.69%, 20.55% and 33.81% of the total area respectively. In future climate scenarios (RCP4.5), the suitable area of Pennisetum alopecuroides (L.) would decrease with climate change, showing a clear trend of northward expansion in China. A concentrated and contiguous distribution region for Pennisetum alopecuroides (L.) would appear in northeast China. The model was tested by the receiver operating characteristic curve (ROC), and the average area under the curve of ROC of the training set was 0.985, which was reliable. This work provided an important reference and theoretical basis for the efficient utilization and plant regionalization of Pennisetum alopecuroides (L.) in future.

In-situ micro-Raman study of SnSe single crystals under atmosphere: Effect of laser power and temperature.

Single crystal of tin selenide (SnSe) was studied by micro-Raman spectroscopy under atmosphere conditions. The effect of varying the incident laser power on the sample up to 2 mW was analyzed. The Raman spectra showed that the number of all vibrational modes have not decreased or increased, but all peaks red-shifted and softened obviously as the laser power increased to the threshold value. The temperature-dependent micro-Raman study of the single crystal was carried out for illustrating thermal effect due to the high incident laser power. A new SnSe2 phase appeared at high temperature without vacuum and become the dominant phase at the surface of the crystal gradually because of oxidation. Detecting few amounts of SnSe2 crystals on the surface of single crystal shows the high sensitivity of Raman spectroscopy. High resolution transmission electron microscopy (HRTEM) was also used to confirm that the newly generated SnSe2 phase is precipitated by SnSe under high temperature oxidation conditions. To study the Raman spectra of low thermal conductivity materials under high temperature and non-vacuum conditions, lower incident laser power should be used to avoid the influence of additional thermal effects.