Ultra Low-Dose Radiation: Stress Responses and Impacts Using Rice as a Grass Model

We report molecular changes in leaves of rice plants (Oryza sativa L. - reference crop plant and grass model) exposed to ultra low-dose ionizing radiation, first using contaminated soil from the exclusion zone around Chernobyl reactor site. Results revealed induction of stress-related marker genes (Northern blot) and secondary metabolites (LC-MS/MS) in irradiated leaf segments over appropriate control. Second, employing the same in vitro model system, we replicated results of the first experiment using in-house fabricated sources of ultra low-dose gamma (γ) rays and selected marker genes by RT-PCR. Results suggest the usefulness of the rice model in studying ultra low-dose radiation response/s.     

In Genes We Trust: The Biological Component of Psychological Essentialism and Its Relationship to Mechanisms of Motivated Social Cognition.

Three studies analyzed the biological component of psychological essentialism (laypeople's belief that social categories have an underlying nature/natural foundation) as it pertains to mechanisms of motivated social cognition. A new scale assessing the belief in genetic determinism is introduced as a measure of the biological component of essentialism. Results speak to the reliability and validity of the scale and show that essentialist beliefs are associated with basic social-cognitive motives and are also related to processes of stereotyping and prejudice. An experimental study found that rendering essentialist information salient elicits increased levels of prejudice and in-group bias, particularly in persons holding chronic essentialist beliefs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic mapping of the α-galactosidase MEL gene family on right and left telomeres of Saccharomyces cerevisiae

The α-galactosidase MEL2–MEL10 genes have been genetically mapped to right and left telomere regions of the following chromosomes of Saccharomyces cerevisiae: MEL2 at VII L, MEL3 at XVI L, MEL4 at XI L, MEL5 at IV L, MEL6 at XIII R, MEL7 at VI R, MEL8 at XV R, MEL9 at X R and MEL10 at XII R. A set of tester strains with URA3 inserted into individual telomeres and no MEL genes was used for mapping.     

Isolation and characterization of peroxisomal protein import (Pim−) mutants of Hansenula polymorpha

In the course of our studies on the molecular mechanisms involved in peroxisome biogenesis, we have isolated several mutants of the methylotrophic yeast Hansenula polymorpha impaired in the import of peroximal matrix proteins. These mutants are characterized by the presence of small intact peroxisomes, while the bulk of the peroxisomal matrix protein is not imported and resides in the cytosol (Pim^? phenotype). Genetic analysis of back-crossed mutants revealed five different complementation groups, which were designated PERI–PER5. Mapping studies to determine the linkage relationships indicated that the observed Pim^? phenotypes were determined by single recessive nuclear mutations. The different mutants had comparable phenotypes: (i) they were impaired to utilize methanol as the sole source of carbon and energy but grew well on various other compounds, including nitrogen sources, the metabolism of which is known to be mediated by peroxisome-borne enzymes in wild-type cells; (ii) all peroxisomal enzymes tested were induced, assembled and activated as in wild-type cells although their activities varied between the different representative mutants; (iii) all peroxisomal proteins, whether constitutive or inducible, were found both in the cytosol and in the small peroxisomes. These results suggest that a general, major import mechanism is affected in all mutants.     

不同时点果蝇七氟醚麻醉相关基因的筛选与分析

目的:在不同时点筛选七氟醚麻酚相关基因,为阐明其作用的分子机制提供有益的线索.方法:以野生品系黑腹果蝇为实验材料,将果蝇分为两组:(1)七氟醚5min组:①空气小组(H5):通入空气5分钟:②七氟醚小组(1H5):七氟醚麻醉5分钟.(1)七氟醚20min组:①空气小组(H20):通入空气20分钟;②七氟醚小组(1H20):七氟醚麻醉20分钟.采用基因表达谱芯片方法,以每组的空气小组为对照分别筛选其七氟醚麻醉小组的差异表达基因.结果:七氟醚5min组筛选出差异表达基因156个,七氟醚20min组13个.对这些差异表达基因进行功能分析发现七氟醚5min组中一些基因的功能为钠:氢反向转运体活性、GTP结合等.七氟醚20min组中一些基因的功能为核酸结合,mRNA结合等,其中功能与钙离了通道、ATP活性、锌离子结合等有关的基因在两组都有改变.结论:许多基因在麻醉初期都活跃表达,还有一些基因表达贯穿麻醉过程,说明麻醉是一个连续的动态过程.     

Microbial community dynamics in replicate membrane bioreactors - Natural reproducible fluctuations

We operated 4 replicate membrane bioreactors (MBRs) in parallel to test if an acclimated seed inoculum would evolve similarly following even distribution into replicates. A cloning and sequencing library of 16S rRNA genes was obtained from the seed inoculum complemented with terminal restriction fragment length polymorphism (T-RFLP; n = 18 per reactor) analysis over the study period (n = 113 d) that targeted the 16S rRNA gene. The amoA functional gene was also monitored by T-RFLP. The T-RFLP results were analyzed by means of diversity indices, an adaptation of a moving window of similarity approach within each MBR, and non-metric multi-dimensional scaling (NMS) accompanied with multi-response permutation procedures (MRPP) to assess community interrelationships amongst MBRs. Based on the 16S rRNA microbial communities, the 4 MBRs initially diverged away from one another, followed by a convergence on Day 4. From thereon, the 16S rRNA-based communities evolved similarly throughout (average p-value = 0.49 from pair-wise MRPP). In contrast, the nitrifying communities did not undergo any discernable shift over time amongst MBRs according to T-RFLP analysis of amoA and revealed one cluster by NMS (average p-value = 0.83 from pair-wise MRPP). The study demonstrates that acclimated microbial communities evolve similarly over time in engineered systems when operational parameters are left unchanged.