Two Hox cofactors, the Meis/Hth homolog UNC-62 and the Pbx/Exd homolog CEH-20, function together during C. elegans postembryonic mesodermal development

The TALE homeodomain-containing PBC and MEIS proteins play multiple roles during metazoan development. Mutations in these proteins can cause various disorders, including cancer. In this study, we examined the roles of MEIS proteins in mesoderm development in C. elegans using the postembryonic mesodermal M lineage as a model system. We found that the MEIS protein UNC-62 plays essential roles in regulating cell fate specification and differentiation in the M lineage. Furthermore, UNC-62 appears to function together with the PBC protein CEH-20 in regulating these processes. Both unc-62 and ceh-20 have overlapping expression patterns within and outside of the M lineage, and they share physical and regulatory interactions. In particular, we found that ceh-20 is genetically required for the promoter activity of unc-62, providing evidence for another layer of regulatory interactions between MEIS and PBC proteins.     

LncRNA MAYA promotes iron overload and hepatocyte senescence through inhibition of YAP in non-alcoholic fatty liver disease

Although recent evidence has shown that hepatocyte senescence plays a crucial role in the pathogenesis and development of non-alcoholic fatty liver disease (NAFLD), the mechanism is still not clear. The purpose of this study was to investigate the signal transduction pathways involved in the senescence of hepatocyte, in order to provide a potential strategy for blocking the process of NAFLD. The results confirmed that hepatocyte senescence occurred in HFD-fed Golden hamsters and PA-treated LO2 cells as manifested by increased levels of senescence marker SA-β-gal, p16 and p21, heterochromatin marker H3K9me3, DNA damage marker γ-H2AX and decreased activity of telomerase. Further studies demonstrated that iron overload could promote the senescence of hepatocyte, whereas the overexpression of Yes-associated protein (YAP) could blunt iron overload and alleviate the senescence of hepatocyte. Of importance, depression of lncRNA MAYA (MAYA) reduced iron overload and cellular senescence via promotion of YAP in PA-treated hepatocytes. These effects were further supported by in vivo experiments. In conclusion, these data suggested that inhibition of MAYA could up-regulate YAP, which might repress hepatocyte senescence through modulating iron overload. In addition, these findings provided a promising option for heading off the development of NAFLD by abrogating hepatocyte senescence.     

Biochemical and photochemical changes in response to triacontanol in rice (Oryza sativa L.)

Triacontanol (TRIA) increased the contents of total chlorophyll (Chl), Chl a and Chl b by 25.1%, 26.1% and 22.4% respectively 4 h after treatment in rice seedlings. The minimal fluorescence (F₀), the maximal fluorescence (Fm) and Fv/Fm were also higher in TRIA-treated plants. In actinic light, other Chl fluorescence parameters were measured at different photon flux densities (PFD) to construct light response curves of the quantum yield of PSII electron transport (_PSII), light response curves of photochemical quenching (qp), and light response curves of non-photochemical quenching (qN), respectively. The _PSII and qp declined with the increasing PFD with a higher level present in TRIA-treated plants. The qN increased with the increasing PFD with a lower level present in TRIA-treated plants. Two-dimensional gel electrophoresis indicated a protein expression difference between TRIA-treated materials and the controls at the total-soluble-protein level. Rubisco was 30% higher in TRIA-treated plants than in controls. The quantity of other proteins was unchanged in response to TRIA. These data provide biochemical and photochemical evidence for the effects of TRIA on photosynthesis.     

镉离子诱导BA/F3β细胞发生奇特的细胞凋亡

细胞凋亡一般都伴随有ＤＮＡ 片段化, 活性氧含量增加, 并能被过量的Ｂｃｌ２ 所抑制。以ＢＡ／Ｆ３β细胞为模型, 利用ＭＴＴ 检测、Ｈｏｃｈｅｓｔ 染色以及透射电镜检测等技术却发现, 镉离子虽然可以诱导该细胞凋亡, 但是这种凋亡没有ＤＮＡ 片段化, 也没有活性氧含量增加。此外, 过量Ｂｃｌ２ 对这种凋亡也没有保护作用。因此, 可以确认镉离子诱导ＢＡ／Ｆ３β细胞发生了奇特的细胞凋亡。     

切断鸣管神经支对红嘴相思鸟鸣声的影响

该研究以红嘴相思鸟(Leiothrix lutea)为材料,分析对其鸣管神经支(NXIIts)进行断单侧和断双侧处理后的鸣声声学变化,探讨鸣管神经支配特性。结果表明,断单侧NXIIts后红嘴相思鸟均可发出常见叫声,但鸣声音节间隔拉长,音节时程缩短,调频指数下降,且断左侧NXIIts的作用效果明显大于断右侧NXIIts。即NXIIts支配具单侧性,且呈左侧优势,此外,左侧NXIIts还具有产生音节高频成分和谐波的作用。断双侧NXIIts后,红嘴相思鸟鸣声音调唯一,响度大幅下降,音节脉冲数增加。     

Impact of nonrandom selection mechanisms on the causal effect estimation for two-sample Mendelian randomization methods

Nonrandom selection in one-sample Mendelian Randomization (MR) results in biased estimates and inflated type I error rates only when the selection effects are sufficiently large. In two-sample MR, the different selection mechanisms in two samples may more seriously affect the causal effect estimation. Firstly, we propose sufficient conditions for causal effect invariance under different selection mechanisms using two-sample MR methods. In the simulation study, we consider 49 possible selection mechanisms in two-sample MR, which depend on genetic variants (G), exposures (X), outcomes (Y) and their combination. We further compare eight pleiotropy-robust methods under different selection mechanisms. Results of simulation reveal that nonrandom selection in sample II has a larger influence on biases and type I error rates than those in sample I. Furthermore, selections depending on X+Y, G+Y, or G+X+Y in sample II lead to larger biases than other selection mechanisms. Notably, when selection depends on Y, bias of causal estimation for non-zero causal effect is larger than that for null causal effect. Especially, the mode based estimate has the largest standard errors among the eight methods. In the absence of pleiotropy, selections depending on Y or G in sample II show nearly unbiased causal effect estimations when the casual effect is null. In the scenarios of balanced pleiotropy, all eight MR methods, especially MR-Egger, demonstrate large biases because the nonrandom selections result in the violation of the Instrument Strength Independent of Direct Effect (InSIDE) assumption. When directional pleiotropy exists, nonrandom selections have a severe impact on the eight MR methods. Application demonstrates that the nonrandom selection in sample II (coronary heart disease patients) can magnify the causal effect estimation of obesity on HbA1c levels. In conclusion, nonrandom selection in two-sample MR exacerbates the bias of causal effect estimation for pleiotropy-robust MR methods.     

The Component and Functional Pathways of Gut Microbiota are Altered in Populations with Poor Sleep Quality – A Preliminary Report

With the development of genome sequencing, many researchers have investigated the mechanism by which the intestinal microbiota influences sleep across the brain-gut axis. However, the relationship between gut microbiota and sleep disorder remains unclear. Thus, we studied the difference in gut microbiota composition between poor sleep quality- and normal populations, which helps set the ground for future research. The recruited college students provided baseline information and stool samples and completed the Pittsburgh Sleep Quality Index (PSQI). We compared the two groups’ gut microbiota composition and functional differentiation by using the 16S rRNA gene sequencing analysis. The main bacterial difference and the most critical effect were mainly concentrated within Tenericutes and Elusimicrobia. Compared with the healthy control group, some functions of the gut microbiota were impaired in the poor sleep quality group, such as butanoate metabolism and propanoate metabolism. Bacterial taxa with significant differences raised the possibility for future diagnosis and treatment of sleep problems.     

栗山天牛天敌花绒寄甲在栎林中的种群保持机制

花绒寄甲(Dastarcus helophoroides)(鞘翅目:寄甲科Bothrideridae)是寄生栗山天牛(Massicus raddei)中老龄幼虫和蛹的重要天敌,但其寄主栗山天牛世代周期长(3年1代)、发育比较整齐,不利于寄生性天敌种群数量的稳定.为了解利用花绒寄甲防治栗山天牛后,其种群能否在栎树林间长期保持较高的种群数量,达到持续控制栗山天牛的防治效果,调查研究了花绒寄甲在栎树林间的转主寄主和种群保持机制.结果表明,在东北辽东栎树干和树枝上除了栗山天牛外,还有其他8种天牛危害:双簇天牛(Moechotypa diphysis)、四点象天牛(Mesosa myops)、中华薄翅锯天牛(Megopis sinica)、锯天牛(Prionus insularis)、双带粒翅天牛(Lamiomimus gottschei)、八字绿虎天牛(Chlorophorus tohokensis)、日本绿虎天牛(C.japonicus)和拟蜡天牛(Stenygrinumquadrinotatum).其中以栗山天牛、双簇天牛、四点象天牛和拟蜡天牛数量较多,而花绒寄甲在辽东栎树干上的垂直分布与栗山天牛、双簇天牛和四点象天牛的垂直分布重叠较多.室内研究表明,花绒寄甲对四点象天牛老熟幼虫的寄生率达到26.67％,对蛹的寄生率达到了43.33％;对双簇天牛老熟幼虫的寄生率达到20.00％,对蛹的寄生率为6.67％.对双簇天牛和四点象天牛在林间的生活史调查和研究发现,花绒寄甲可寄生的这两种天牛的中老龄幼虫和蛹,在花绒寄甲不适宜寄生的栗山天牛幼龄幼虫期大量存在,表明双簇天牛和四点象天牛是花绒寄甲在栎树林中的主要转主寄主.由于这些转主寄主的存在,花绒寄甲在不利于其寄生的栗山天牛卵期、幼龄幼虫期可转移寄生这些寄主,从而在栗山天牛危害的栎树林间保持了较高的种群数量,达到对栗山天牛长期而有效的持续控制效果.