Proteomic analysis of effect of hyperthermia on spermatogenesis in adult male mice

We characterized cellular and molecular mechanisms involved in spermatogenesis following short-term heat exposure of murine testis. For these studies, we utilized a proteomic approach with two-dimensional gel electrophoresis (2DE) analyses and mass spectroscopic identification of proteins with altered expression in mouse testes at different times after heat shock. We established a proteome reference map from 7-wk-old mouse testis linked to a federated proteome database. We used these tools to analyze quantitative variations in the tissue over a time course of 0.5, 2, 6, and 12 h following heat exposure. We separated 108 protein spots expressed differentially between the heat shock tissues and the control mouse testes. Of these spots, we identified 36 by comparing with the control reference map. We then focused on the heterogeneous nuclear ribonucleoproteins (hnRNPs) and the chaperonins containing t-complex polypeptide-1 (CCT). Further analysis in this heat-shocked model suggests numerous potential mechanisms for heat shock-induced spermatogenic disorder.     

Comprehensive proteomic analysis of Shigella flexneri 2a membrane proteins

Shigella flexneri is the causative agent of most shigellosis cases in developing countries. We used different proteolytic enzymes to selectively shave the protruding proteins on the surface of purified bacterial membrane sheets or vesicles, and recovered peptides were subsequently identified using 2-D LC-MS/MS. As a result, a total of 666 proteins were unambiguously assigned, including 159 integral membrane proteins, 35 outer membrane proteins and 114 proteins previously annotated as hypothetical. The former had an average grand average hydrophobicity score of 0.362 and were predicted to separate within a pH range of 4.1-10.6 with molecular mass 8-148 kDa, which represents the largest validated set of integral membrane proteins in this organism to date. A functional classification revealed that a large proportion of the identified proteins were involved in cell envelope biogenesis and energy production and conversion. For the first time, this work provides a global view of the S. flexneri 2a membrane subproteome.     

Maternal birthplace and major congenital malformations among New York Hispanics

BACKGROUND: Little is known about the association between maternal nativity and congenital malformations among Hispanics living in the United States. METHODS: We conducted a cross-sectional study to investigate the association between maternal nativity and various congenital malformations among singleton live-births born to Hispanic women in New York from 1993 to 2001. Birth certificates, used to identify maternal birthplace, were linked with congenital malformation registry files to obtain birth defects outcome. We examined how the risk of birth defects varied by maternal birthplace by estimating the adjusted odds ratios (aORs) using logistic regression. RESULTS: A foreign maternal birth showed statistically negative associations with overall congenital malformations (aOR, 0.70; 95% CI, 0.68-0.73), cardiovascular defects (aOR, 0.85; 95% CI, 0.77-0.93), central nervous system defects (aOR, 0.76; 95% CI, 0.63-0.91), and multiple defects (aOR, 0.80; 95% CI, 0.74-0.86). Specifically, foreign-born Hispanic women were statistically at reduced risk to deliver live babies with cleft palate (aOR, 0.56; 95% CI, 0.40-0.80), atresia and stenosis of rectum or anus (aOR, 0.58; 95% CI, 0.35-0.97), and craniosynostosis (aOR, 0.71; 95% CI, 0.51-0.99). Hispanic mothers born in Puerto Rico had a similar risk of delivering children with birth defects compared to U.S.-born Hispanic mothers. In contrast, Hispanic mothers born in Mexico, or Cuba and Central and South America were at reduced risk of delivering infants with overall congenital malformations (aOR, 0.64; 95% CI, 0.60-0.67) and (aOR, 0.65; 95% CI, 0.63-0.68), respectively. CONCLUSIONS: Foreign-born Hispanic mothers had a slightly lower risk to deliver live-born singleton infants with major congenital malformations than did U.S. born Hispanic mothers.     

Adaptive character of metabolism in Eothenomys miletus in Hengduan Mountains region during cold acclimation

Environmental factors play an important role in the seasonal adaptation of body mass and thermogenesis in small, wild mammals. The purpose of the present study was to test the hypothesis that ambient temperature was a cue to trigger the seasonal adjustments in body mass, energy intake, uncoupling protein 1 (UCP1) in brown adipose tissue (BAT), and other biochemical characteristics of Eothenomys miletus during 49 days of cold exposure. Our data demonstrated that cold acclimation induced a remarkable decrease in body mass, a significant increase in energy intake and metabolic rate, and high expression of UCP1 in BAT of E. miletus. Biochemical characteristics of BAT and liver respiration were also increased following cold acclimation. These data suggest that E. miletus reduced the body mass and increased energy intake and expenditure under cold acclimation. Increased expression of UCP1 was potentially involved in the regulation of energy metabolism and thermogenic capacity following cold acclimation.     

凝溶胶蛋白与创伤后炎症反应

凝溶胶蛋白(gelsolin,GSN)是机体内重要的肌动蛋白结合蛋白,对肌动蛋白的聚合/解聚具有重要调节作用。其生理效应不仅在于维持细胞结构稳定,而且参与多种细胞活动的调节过程,是一种重要的细胞功能调节蛋白。血浆型GSN是血浆肌动蛋白清除系统主要成员之一,对维持内环境稳定非常重要。严重创伤后血浆中GSN水平显著而持续降低,且与患者预后密切相关。本文综述GSN与创伤后炎症反应的关系。     

Reactivation of a silenced minimal Mutator transposable element system following low-energy nitrogen ion implantation in maize

In maize, Mutator transposable elements are either active or silenced within the genome. In response to environmental stress, silenced Mutator elements could be reactivated, leading to changes in genome structure and gene function. However, there is no direct experimental evidence linking environmental stress and Mutator transposon reactivation. Using a maize line that contains a single inactive MuDR and a lone nonautonomous Mutator element, a Mu1 insertion in the recessive reporter allele a1-mum2 in an inactive Mutator background, we directly assessed Mutator reactivation following low-energy nitrogen ion implantation. We observed that N⁺ implantation decreased cytosine methylation in MuDR terminal inverted repeats and increased expression of mudrA and mudrB. Both changes were associated with increased transpositional activity of MuDR through reactivation of the inactive minimal Mutator transposable element system. This study provides direct evidence linking environmental stress agents and Mutator transposon mobilization in maize. In addition, the observed changes to DNA methylation suggest a new mechanism for mutations by low-energy ion implantation.     

A novel PET marker for in vivo quantification of myelination

C-11-labeled N-methyl-4,4'-diaminostilbene ([(11)C]MeDAS) was synthesized and evaluated as a novel radiotracer for in vivo microPET imaging of myelination. [(11)C]MeDAS exhibits optimal lipophilicity for brain uptake with a logP(oct) value of 2.25. Both in vitro and ex vivo staining exhibited MeDAS accumulation in myelinated regions such as corpus callosum and striatum. The corpus callosum region visualized by MeDAS is much larger in the hypermyelinated Plp-Akt-DD mouse brain than in the wild-type mouse brain, a pattern that was also consistently observed in Black-Gold or MBP antibody staining. Ex vivo autoradiography demonstrated that [(11)C]MeDAS readily entered the mouse brain and selectively labeled myelinated regions with high specificity. Biodistribution studies showed abundant initial brain uptake of [(11)C]MeDAS with 2.56% injected dose/whole brain at 5 min post injection and prolonged retention in the brain with 1.37% injected dose/whole brain at 60 min post injection. An in vivo pharmacokinetic profile of [(11)C]MeDAS was quantitatively analyzed through a microPET study in an Plp-Akt-DD hypermyelinated mouse model. MicroPET studies showed that [(11)C]MeDAS exhibited a pharmacokinetic profile that readily correlates the radioactivity concentration to the level of myelination in the brain. These studies suggest that MeDAS is a sensitive myelin probe that provides a direct means to detect myelin changes in the brain. Thus, it can be used as a myelin-imaging marker to monitor myelin pathology in vivo.     

Design,synthesis and biological evaluation of chrysin long-chain derivatives as potential anticancer agents

A series of long-chain derivatives of chrysin (compounds 3–22) were synthesized to evaluate for their antiproliferative activities against the human liver cancer cell line HT-29 and EGFR inhibitory activity. Among the compounds tested, compounds hexadecyl 2-(5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yloxy)acetate (10) and N-hexadecyl 2-(5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yloxy)acetamide (20) displayed potent EGFR inhibitory activity with IC₅₀ values of 0.048 μM and 0.035 μM), comparable to the positive control erlotinib. Docking simulation of compounds 10 and 20 was carried out to illustrate the binding mode of the molecular into the EGFR active site, and the result suggested that compound 10 and 20 can bind the EGFR kinase well. Thus, compounds 10 and 20 with potent EGFR inhibitory activity would be potential anticancer agents.     

Molecular characterization of the <Emphasis Type="Italic">Arginine decarboxylase</Emphasis> gene family in rice

Arginine decarboxylase (ADC) is a key enzyme in plants that converts arginine into putrescine, an important mediator of abiotic stress tolerance. Adc genes have been isolated from a number of dicotyledonous plants but the oat and rice Adc genes are the only representatives of monocotyledonous species described thus far. Rice has a small family of Adc genes, and OsAdc1 expression has been shown to fluctuate under drought and chilling stress. We identified and characterized a second rice Adc gene (OsAdc2) which encodes a 629-amino-acid protein with a predicted molecular mass of 67 kDa. An unusual feature of the OsAdc2 gene is the presence of an intron and a short upstream open reading frame in the 5′-UTR. Sequence comparisons showed that OsAdc2 is more closely related to the oat Adc gene than to OsAdc1 or to its dicot homologs, and mRNA analysis showed that the two rice genes are also differently regulated. Whereas OsAdc1 is expressed in leaf, root and stem, OsAdc2 expression is restricted to stem tissue. Protein expression was investigated with specific antibodies against ADC1 and ADC2, corroborating the mRNA data. We discuss the expression profiles of OsAdc1 and OsAdc2 and potential functions for the two corresponding proteins.