The association between genetic damage in peripheral blood lymphocytes and polymorphisms of three glutathione S-transferases in Chinese workers exposed to 1,3-butadiene

1,3-Butadiene (BD) has been classified as a human carcinogen, group I; however, the relationship between polymorphisms of glutathione S-transferases that metabolize BD and chromosomal damage is not clear. The present study used sister chromatid exchange (SCE) and cytokinesis-block micronucleus (CBMN) assays to detect chromosomal damage in peripheral lymphocytes of 44 BD-exposed workers and 39 non-exposed healthy controls. PCR and PCR-RFLP were employed to detect three known glutathione S-transferase polymorphisms GSTT1, GSTM1, and GSTP1 (Ile105Val). The data demonstrated that the micronucleus (CBMN) frequency in BD-exposed workers was significantly higher than that in controls (frequency ratio (FR) = 1.48, 95% CI: 1.14–1.91, P < 0.01), and the CBMN frequency was higher in workers exposed to higher cumulative BD levels (FR = 1.70, 95% CI: 1.28–2.27, P < 0.01). However, differences in SCE frequency were not observed (FR = 1.14, 95% CI: 0.81–1.61, P > 0.05). Among exposed workers, chromosomal damage was related to BD exposure levels (FR = 1.35, 95% CI: 1.02–1.80, P < 0.05); age, older workers exhibited higher MN frequencies than younger workers (FR = 1.45, 95% CI: 1.14–1.84, P < 0.05); and years of work, those with more years of work exhibited higher MN frequencies than those with fewer years (FR = 1.40, 95% CI: 1.10–1.77, P < 0.05). Multivariate Poisson regression analysis showed that those who carried GSTM1 (?) (FR = 1.48, 95% CI: 1.14–1.92) or GSTT1 (?) (FR = 1.42, 95% CI: 1.10–1.83) genotypes, and especially those who carried both (FR = 2.10, 95% CI: 1.43–3.09) exhibited significantly higher MN frequencies than those carrying GSTM1 (+), GSTT1 (+) genotypes or their combination. The GSTP1 Val genotype did not affect MN frequency (P > 0.05). Our results suggested that higher levels of BD exposure in the workplace resulted in increased chromosomal damage, and that polymorphisms in GSTT1 and GSTM1 genes might modulate the genotoxic effects of BD exposure. Furthermore, the GSTT1 and GSTM1 polymorphisms exhibited an additive effect. Finally, urinary DHBMA was found to provide a biomarker that correlated with airborne BD levels.     

3,3′,4,4′,5-Pentachlorobiphenyl influences mitochondrial apoptosis pathway in granulosa cells

3,3′,4,4′,5-Polychlorinated biphenyl (PCB126) is a persistent organic environmental pollutant which can affect various biological activities of organisms, such as immunity, neurological function, and reproduction. In our study, we aimed to investigate the effects of PCB126 on granulosa cells (GCs). GCs were collected from ovaries in PMSG-treated mice, after 24 hours culture. GCs were then incubated with 10 pg/mL, 100 pg/mL, and 10 ng/mL of PCB126 for another 24 hours. Following these steps, exposed GCs were collected for further experimentation. Our data showed that the number of GCs in the 10 ng/mL PCB126 decreased. Meanwhile, pyknotic nuclei and condensed chromatin increased, while the apoptotic cells in the 10 ng/mL PCB126 group were significantly increased. Furthermore, the expression of the apoptotic executive protein caspase-3 increased after PCB126 treatment. The expression of Bax, Bcl-2, and Bim related to the mitochondrial apoptosis pathway were also influenced to different degrees. Thus, our data suggested that PCB126 affect the GCs apoptosis, and mitochondrial apoptosis pathway was involved in this process.     

ERK1/2在高温致神经管畸形神经上皮细胞中的表达变化

目的 探讨高温致神经管畸形(NTDs)作用的分子机制,为防治NTDs的发生提供理论依据.方法 在高温致金黄地鼠NTDs模型的基础上,应用免疫荧光染色技术,观察NTDs发生过程中p-ERK1/2在鼠胚神经上皮细胞中的表达变化.结果 对照组和实验组孕鼠在高温水浴处理后16、24h,p-ERK1/2免疫阳性产物分布于鼠胚神经上皮细胞和周围间充质细胞的胞浆中;水浴后36、60h,p-ERK1/2表达部位出现了由细胞浆向细胞核的转移;高温处理后,p-ERK1/2在实验组各期胚胎神经上皮细胞内的表达均比对照组减弱.结论 ERK1/2参与胚胎神经管的发育过程,其表达降低在高温致神经管畸形的发生中起重要作用.     

基于无人机影像的阿拉善东南部荒漠灌丛植被空间格局研究

干旱区灌丛植被空间格局受多种物理和生态过程影响，能够指示生态系统的状态。研究通过量化灌丛斑块大小的空间分布来评估阿拉善高原东南部覆沙荒漠植被生态系统的状态，采用点格局分析法分析灌木种群的相互关系，以阐明不同灌木种在斑块格局形成中的作用，并结合土壤条件及下垫面粗糙度等指标验证评估的准确性，探讨灌丛空间格局差异的内在机理。结果表明，研究区样方2灌丛斑块大小符合截尾幂律分布，其他样方符合对数正态分布，前者的空间结构及生境条件均优于后者，说明植被空间格局可以准确表征生态系统状态。在局地尺度上灌木种内和种间呈现不同的相互关系，以竞争关系为主导是导致斑块破碎化的主要驱动机制。小灌木（如猫头刺）的种内互利关系有利于促进多样化斑块形态的形成，而大灌木（如沙冬青和蒙古扁桃）种间的互利作用则有利于形成异质性更强的复杂空间格局。基于灌丛斑块的空间格局评估生态系统状态，可为保护和恢复生态脆弱区受损植被提供重要的借鉴。     

Characterization of Bacterial Communities in Deep-Sea Hydrothermal Vents from Three Oceanic Regions

Deep-sea hydrothermal vents are considered to be one of the most spectacular ecosystems on Earth. Microorganisms form the basis of the food chain in vents controlling the vent communities. However, the diversity of bacterial communities in deep-sea hydrothermal vents from different oceans remains largely unknown. In this study, the pyrosequencing of 16S rRNA gene was used to characterize the bacterial communities of the venting sulfide, seawater, and tubeworm trophosome from East Pacific Rise, South Atlantic Ridge, and Southwest Indian Ridge, respectively. A total of 23,767 operational taxonomic units (OTUs) were assigned into 42 different phyla. Although Proteobacteria, Actinobacteria, and Bacteroidetes were the predominant phyla in all vents, differences of bacterial diversity were observed among different vents from three oceanic regions. The sulfides of East Pacific Rise possessed the most diverse bacterial communities. The bacterial diversities of venting seawater were much lower than those of vent sulfides. The symbiotic bacteria of tubeworm Ridgeia piscesae were included in the bacterial community of vent sulfides, suggesting their significant ecological functions as the primary producers in the deep-sea hydrothermal vent ecosystems. Therefore, our study presented a comprehensive view of bacterial communities in deep-sea hydrothermal vents from different oceans.     

High Uric Acid Induces Insulin Resistance in Cardiomyocytes In Vitro and In Vivo

Clinical studies have shown hyperuricemia strongly associated with insulin resistance as well as cardiovascular disease. Direct evidence of how high uric acid (HUA) affects insulin resistance in cardiomyocytes, but the pathological mechanism of HUA associated with cardiovascular disease remains to be clarified. We aimed to examine the effect of HUA on insulin sensitivity in cardiomyocytes and on insulin resistance in hyperuricemic mouse model. We exposed primary cardiomyocytes and a rat cardiomyocyte cell line, H9c2 cardiomyocytes, to HUA, then quantified glucose uptake with a fluorescent glucose analog, 2-NBDG, after insulin challenge and detected reactive oxygen species (ROS) production. Western blot analysis was used to examine the levels of insulin receptor (IR), phosphorylated insulin receptor substrate 1 (IRS1, Ser307) and phospho-Akt (Ser473). We monitored the impact of HUA on insulin resistance, insulin signaling and IR, phospho-IRS1 (Ser307) and phospho-Akt levels in myocardial tissue of an acute hyperuricemia mouse model established by potassium oxonate treatment. HUA inhibited insulin-induced glucose uptake in H9c2 and primary cardiomyocytes. It increased ROS production; pretreatment with N-acetyl-L-cysteine (NAC), a ROS scavenger, reversed HUA-inhibited glucose uptake induced by insulin. HUA exposure directly increased the phospho-IRS1 (Ser307) response to insulin and inhibited that of phospho-Akt in H9C2 cardiomyocytes, which was blocked by NAC. Furthermore, the acute hyperuricemic mice model showed impaired glucose tolerance and insulin tolerance accompanied by increased phospho-IRS1 (Ser307) and inhibited phospho-Akt response to insulin in myocardial tissues. HUA inhibited insulin signaling and induced insulin resistance in cardiomyocytes in vitro and in vivo, which is a novel potential mechanism of hyperuricemic-related cardiovascular disease.     

柑橘基因组DNA快速提取及ISSR-PCR扩增体系优化

对CTAB-mini法进行改良,得到一种效率较高的柑橘DNA提取方法.试验结果表明,得到的高质量DNA适合柑橘ISSR分析.同时,采用正交设计对影响柑橘ISSR-PCR因子进行优化.试验结果表明:20 μl反应体系中采用5 ng模板DNA、0.35 mmol/L dNTPs、0.15 μmol/L Primer、1U Taq酶和3 μl 10×Buffer(含Mg2+)为柑橘ISSR-PCR最优反应体系.     

Acrylamide-Induced Changes in the Neurofilament Protein of Rat Cerebrum Fractions

Acrylamide (ACR) is known to produce central–peripheral distal axonopathy, which is characterized by distal swellings and secondary degeneration both in experimental animals and human. Ultrastructurally, excessive accumulation of neurofilaments (NFs) in the distal swollen axon is a major pathological hallmark. However, the mechanisms of ACR axonopathy remain unknown. Twenty seven male Wistar rats were randomly divided into three groups. Lower and higher ACR groups were received 20 and 40 mg/kg ACR by i.p. injection respectively. The control group received physiological saline. All rats were sacrificed after 8 weeks of treatment and their cerebrums were dissected, homogenized and used for the determination of the NF proteins. In general, the levels of light NF (NF-L) and medium NF (NF-M) subunits increased consistently in the supernatant, whereas they decreased consistently in the pellet from rats treated with ACR. Compared to that of the control group, the levels of NF-L increased respectively by 104% and 45% (P<0.01) in the supernatant and decreased by 16% and 11% (P<0.01) in the pellet of rat cerebrums in lower and higher groups. The enhancement of NF-M was 76% and 147% (P<0.05, P<0.01) in supernatant, and the reduction was 26% and 36% (P<0.01) in pellet in lower and higher group respectively. The heavy NF (NF-H) level changed slightly. The present results suggested that the change of NF-L and NF-M levels in cerebrum might be relevant to the mechanisms of the neurofilamentous axonopathies induced by ACR.     

High‐efficient and precise base editing of C•G to T•A in the allotetraploid cotton (Gossypium hirsutum) genome using a modified CRISPR/Cas9 system

The base‐editing technique using CRISPR/nCas9 (Cas9 nickase) or dCas9 (deactivated Cas9) fused with cytidine deaminase is a powerful tool to create point mutations. In this study, a novel G. hirsutum‐Base Editor 3 (GhBE3) base‐editing system has been developed to create single‐base mutations in the allotetraploid genome of cotton (Gossypium hirsutum). A cytidine deaminase sequence (APOBEC) fused with nCas9 and uracil glycosylase inhibitor (UGI) was inserted into our CRISPR/Cas9 plasmid (pRGEB32‐GhU6.7). Three target sites were chosen for two target genes, GhCLA and GhPEBP, to test the efficiency and accuracy of GhBE3. The editing efficiency ranged from 26.67 to 57.78% at the three target sites. Targeted deep sequencing revealed that the C→T substitution efficiency within an ‘editing window’, approximately six‐nucleotide windows of ?17 to ?12 bp from the PAM sequence, was up to 18.63% of the total sequences. The 27 most likely off‐target sites predicted by CRISPR‐P and Cas‐OFFinder tools were analysed by targeted deep sequencing, and it was found that rare C→T substitutions (average < 0.1%) were detected in the editing windows of these sites. Furthermore, whole‐genome sequencing analyses on two GhCLA‐edited and one wild‐type plants with about 100× depth showed that no bona fide off‐target mutations were detectable from 1500 predicted potential off‐target sites across the genome. In addition, the edited bases were inherited to T1 progeny. These results demonstrate that GhBE3 has high specificity and accuracy for the generation of targeted point mutations in allotetraploid cotton.