NaCl胁迫下哈茨木霉ACCC32524的转录组和代谢组分析

【目的】通过分析NaCl胁迫下哈茨木霉(Trichoderma harzianum)ACCC32524转录组和代谢组数据,研究差异表达基因及次级代谢产物的变化情况,初步探索响应NaCl胁迫的分子机制。【方法】利用Illumina HiSeq XTen高通量测序平台完成0、0.4、0.6 mol/L NaCl浓度胁迫培养下哈茨木霉ACCC32524的转录组测序,GC-TOF-MS技术完成对0mol/L和0.6mol/LNaCl胁迫培养下的差异次级代谢产物检测,利用相关软件及数据库对差异表达基因(DEGs)和次级代谢产物的注释、筛选和分类,并进行RT-qPCR验证。【结果】本研究分别得到0.4 mol/L和0.6 mol/L NaCl胁迫下417和733条差异表达基因;GO富集分析显示,分别有318和582条差异表达基因注释到生物学过程、分子功能和细胞组分3个一级分类和40个二级分类;COG分类结果表明分别有232和414条转录本为20个类别,涉及差异表达基因最多的分别为氨基酸的转运和代谢、一般功能预测、碳水化合物的转运和代谢;KEGG代谢途径分析结果表明,分别有75和96条基因归到25个代谢通路中(P≤0.05),其中涉及差异基因最多的是氨基酸的生物合成和2-氧代羧酸代谢通路。从转录组数据中共筛选出与渗透调节、离子转运、活性氧清除等22个耐盐相关基因。0 mol/L和0.6 mol/L NaCl胁迫下的代谢组数据中共筛选出101个差异次级代谢产物,包括8种积累量上调和93种下调物质,其中36个得到定性,分属于糖类、有机酸和氨基酸等9个分类中。RT-qPCR验证挑选的差异表达基因的表达量变化,均与RNA-seq分析结果一致。【结论】NaCl胁迫下引起哈茨木霉ACCC32524基因及次级代谢产物发生明显变化,细胞代谢途径发生明显偏移,这些进程共同作用减少NaCl对细胞的毒害作用,为木霉菌的耐盐机理研究提供重要信息。     

A Novel Newborn Rat Kernicterus Model Created by Injecting a Bilirubin Solution into the Cisterna Magna

Background

Kernicterus still occurs around the world; however, the mechanism of bilirubin neurotoxicity remains unclear, and effective treatment strategies are lacking. To solve these problems, several kernicterus (or acute bilirubin encephalopathy) animal models have been established, but these models are difficult and expensive. Therefore, the present study was performed to establish a novel kernicterus model that is simple and affordable by injecting unconjugated bilirubin solution into the cisterna magna (CM) of ordinary newborn Sprague-Dawley (SD) rats.

Methods

On postnatal day 5, SD rat pups were randomly divided into bilirubin and control groups. Then, either bilirubin solution or ddH₂O (pH = 8.5) was injected into the CM at 10 µg/g (bodyweight). For model characterization, neurobehavioral outcomes were observed, mortality was calculated, and bodyweight was recorded after bilirubin injection and weaning. Apoptosis in the hippocampus was detected by H&E staining, TUNEL, flow cytometry and Western blotting. When the rats were 28 days old, learning and memory ability were evaluated using the Morris water maze test.

Results

The bilirubin-treated rats showed apparently abnormal neurological manifestations, such as clenched fists, opisthotonos and torsion spasms. Bodyweight gain in the bilirubin-treated rats was significantly lower than that in the controls (P<0.001). The early and late mortality of the bilirubin-treated rats were both dramatically higher than those of the controls (P = 0.004 and 0.017, respectively). Apoptosis and necrosis in the hippocampal nerve cells in the bilirubin-treated rats were observed. The bilirubin-treated rats performed worse than the controls on the Morris water maze test.

Conclusion

By injecting bilirubin into the CM, we successfully created a new kernicterus model using ordinary SD rats; the model mimics both the acute clinical manifestations and the chronic sequelae. In particular, CM injection is easy to perform; thus, more stable models for follow-up study are available.     

新型冠状病毒(SARS-CoV-2)蛋白靶位的生信分析

目前新型冠状病毒肺炎(COVID-19)疫情仍在全球肆虐,但尚无针对该病毒的治疗特效药.在此背景,以美国化学文摘社(Chemical Abstracts Service,CAS)提供的SARS-CoV-2病毒及宿主蛋白靶标为研究对象,运用基因功能富集、蛋白网络等方法进行生物信息分析.结果发现,人网格蛋白介导型内吞和依赖...     

RP4质粒及其带动的硫杆菌重组质粒psDt125在氧化硫硫杆菌中的接合转移

本实验选择了一种大肠杆菌(E.coli)和氧化硫硫杆菌(Thiobacillusthiooxidans)均能生长的接合培养基。以大肠杆菌E.coli C600(RP4)为供体,以氧化硫硫杆菌T.t-3为受体,通过接合,直接将RP4质粒转移到氧化硫硫杆菌中,其Km~r,Tc~r基因得到表达,但Ap~r基因不表达。再将RP4质粒反向接合转移到E.coliHB101上,其三个抗性基因均表达。并且利用RP4质粒的带动将硫杆菌重组质粒psDt125直接转入氧化硫硫杆菌,其Cm~r基因表达。从而为氧化硫硫杆菌的基因工程改造提供了一条简便可行的遗传信息转移途径。     

The association of garlic with Helicobacter pylori infection and gastric cancer risk: A systematic review and meta‐analysis

Background

Garlic may be protective against Helicobacter pylori infection and gastric cancer development. We conducted this study to quantitatively update evidence on garlic intake and gastric cancer with the inclusion of most recent cohort studies and qualitatively summarize epidemiological studies of garlic consumption and Helicobacter pylori infection.

Materials and Methods

PubMed, Embase, MEDLINE, and Cochrane Library were searched on April 2018. We conducted a meta‐analysis to determine whether garlic intake reduced gastric cancer risk using random‐effect models and a systematic review to summarize evidence on the association between garlic consumption and Helicobacter pylori infection. Risk of bias was assessed using tools of Cochrane risk of bias and Robins‐I for randomized and nonrandomized studies, respectively.

Results

Meta‐analysis of 18 studies (142 921 subjects) demonstrated high garlic consumption (as comparing the highest category to the lowest) was associated with a reduced gastric cancer risk (OR = 0.51, 95% CI = 0.44‐0.57). This association became nonsignificant if only derived from the prospective studies (OR = 0.95, 95% CI = 0.66‐1.24). Thirteen studies (4889 participants) were included in the systematic review for garlic consumption and Helicobacter pylori infection; ten of which found no significant results. The majority of these studies were poor in quality given the small sample size and high risk of bias.

Conclusions

Pooled evidence, mainly from case‐control studies, suggested a significant inverse association of garlic intake with gastric cancer risk. Given the limitations of included studies, current epidemiological evidence is not sufficient to reach any definite conclusion regarding the association of garlic with Helicobacter pylori infection.     

Characterization of goose SPMS: Molecular characterization and expression profiling of SPMS in the goose ovary

Spermine synthase (SPMS), which converts spermidine into spermine, is essential for normal cell growth and development processes in humans and other mammals, but the molecular characterization and expression profiling of the SPMS gene remain undetermined in goose tissues and ovarian follicles. In this study, the SPMS cDNA sequence of the Sichuan white goose was cloned and analysed, and SPMS mRNA expression was profiled in various tissues and ovarian follicles. The results showed that the open reading frame of the SPMS cDNA sequence was 1092?bp in length, encoding 363 amino acids with a molecular weight of 41?kDa. Among all the examined tissues, SPMS expression was highest in the spleen and cerebrum and lowest in the breast and thigh muscles. SPMS expression in the F1 follicle was significantly higher than that in the POF (except for POF2) (P?<?0.05). Our results indicate that SPMS might play an important role in follicular development and ovulation.