Observation of protein folding/unfolding dynamics of ubiquitin trapped in agarose gel by single-molecule FRET

A ubiquitin mutant with two Cys mutations, m[C]q/S65C, was site-specifically labeled with two dye molecules, Alexa Fluor 488 (donor) and Alexa Fluor 594 (acceptor), due to the different reactivity of these two Cys residues. This doubly dye-labeled ubiquitin has lower structural stability than wild-type ubiquitin. Taking advantage of this decreased stability, conformational heterogeneity of this protein under nondenaturing condition was observed at the single-molecule level using single-paired Förster resonance energy transfer (FRET) by trapping the protein in agarose gel. Three conformational populations corresponding to folded (E _ET ≈ 0.95), loosely packed (E _ET ≈ 0.72), and unfolded (E _ET ≈ 0.22) structures, and the structural transitions between them were observed. Our results suggest that agarose immobilization is good for observing structural dynamics of proteins under native condition.     

Glycogen phosphorylase in glycogen-rich cells is involved in the energy supply for ion regulation in fish gill epithelia

The molecular and cellular mechanisms behind glycogen metabolism and the energy metabolite translocation between mammal neurons and astrocytes have been well studied. A similar mechanism is proposed for rapid mobilization of local energy stores to support energy-dependent transepithelial ion transport in gills of the Mozambique tilapia (Oreochromis mossambicus). A novel gill glycogen phosphorylase isoform (tGPGG), which catalyzes the initial degradation of glycogen, was identified in branchial epithelial cells of O. mossambicus. Double in situ hybridization and immunocytochemistry demonstrated that tGPGG mRNA and glycogen were colocalized in glycogen-rich cells (GRCs), which surround ionocytes (labeled with a Na(+)-K(+)-ATPase antiserum) in gill epithelia. Concanavalin-A (a marker for the apical membrane) labeling indicated that GRCs and mitochondria-rich cells share the same apical opening. Quantitative real-time PCR analyses showed that tGPGG mRNA expression levels specifically responded to environmental salinity changes. Indeed, the glycogen content, glycogen phosphorylase (GP) protein level and total activity, and the density of tGPGG-expressing cells (i.e., GRCs) in fish acclimated to seawater (SW) were significantly higher than those in freshwater controls. Short-term acclimation to SW caused an evident depletion in the glycogen content of GRCs. Taken altogether, tGPGG expression in GRCs is stimulated by hyperosmotic challenge, and this may catalyze initial glycogen degradation to provide the adjacent ionocytes with energy to carry out iono- and osmoregulatory functions.     

苹果蠹蛾老熟幼虫诱杀技术

本文对简易杀虫诱集带诱杀苹果蠹蛾Cydia pomonella(L.)老熟幼虫的效果进行了研究。发现在编织袋,旧衣物,瓦楞纸3种材料中,旧衣物对苹果蠹蛾的老熟幼虫捕获效果最好,其诱捕量占总诱捕量的68.42%;在诱集带中添加的农药中(包括乐斯本、敌敌畏、白僵菌、灭幼脲3号、高效氯氰菊酯等),乐斯本的杀虫效果最好,幼虫死亡率达到98.20%;在不同浓度的乐斯本溶液中,500倍乐斯本杀虫效果最好,幼虫死亡率达到91.61%,且对幼虫没有驱避作用;500倍乐斯本+50倍白僵菌药杀虫诱集带有效期长达40多天,37d后对幼虫的杀伤效果依然达到96%以上,作为老熟幼虫的防治措施十分理想。     

PDA: Pooled DNA analyzer

Background  

Association mapping using abundant single nucleotide polymorphisms is a powerful tool for identifying disease susceptibility genes for complex traits and exploring possible genetic diversity. Genotyping large numbers of SNPs individually is performed routinely but is cost prohibitive for large-scale genetic studies. DNA pooling is a reliable and cost-saving alternative genotyping method. However, no software has been developed for complete pooled-DNA analyses, including data standardization, allele frequency estimation, and single/multipoint DNA pooling association tests. This motivated the development of the software, 'PDA' (Pooled DNA Analyzer), to analyze pooled DNA data.     

A large-scale survey of genetic copy number variations among Han Chinese residing in Taiwan

Background

Winter migration of immature brown trout (Salmo trutta) into freshwater rivers has been hypothesized to result from physiologically stressful combinations of high salinity and low temperature in the sea.

Results

We sampled brown trout from two Danish populations entering different saline conditions and quantified expression of the hsp70 and Na/K-ATPases α 1b genes following acclimation to freshwater and full-strength seawater at 2°C and 10°C. An interaction effect of low temperature and high salinity on expression of both hsp70 and Na/K-ATPase α 1b was found in trout from the river entering high saline conditions, while a temperature independent up-regulation of both genes in full-strength seawater was found for trout entering marine conditions with lower salinities.

Conclusion

Overall our results support the hypothesis that physiologically stressful conditions in the sea drive sea-run brown trout into freshwater rivers in winter. However, our results also demonstrate intra-specific differences in expression of important stress and osmoregulative genes most likely reflecting adaptive differences between trout populations on a regional scale, thus strongly suggesting local adaptations driven by the local marine environment.     

Linkage Analyses of Chromosome 18 Markers Do Not Identify a Major Susceptibility Locus for Bipolar Affective Disorder in the Old Order Amish

Previously reported linkage of bipolar affective disorder to DNA markers in the pericentromeric region of chromosome 18 was reexamined in a larger homogeneous sample of Old Order Amish families. Four markers (D18S21, D18S53, D18S44, and D18S40) were examined in three kindreds containing 31 bipolar I (BP I) individuals. Although linkage findings were replicated in the one previously studied Amish pedigree containing four BP I individuals, linkage to this region was excluded in the larger sample. If a susceptibility locus for bipolar disorder is located in this region of chromosome 18, it is of minor significance in this population.     

On the use of multifactor dimensionality reduction (MDR) and classification and regression tree (CART) to identify haplotype-haplotype interactions in genetic studies

Haplotype-based approaches may have greater power than single-locus analyses when the SNPs are in strong linkage disequilibrium with the risk locus. To overcome potential complexities owing to large numbers of haplotypes in genetic studies, we evaluated two data mining approaches, multifactor dimensionality reduction (MDR) and classification and regression tree (CART), with the concept of haplotypes considering their haplotype uncertainty to detect haplotype-haplotype (HH) interactions. In evaluation of performance for detecting HH interactions, MDR had higher power than CART, but MDR gave a slightly higher type I error. Additionally, we performed an HH interaction analysis with a publicly available dataset of Parkinson's disease and confirmed previous findings that the RET proto-oncogene is associated with the disease. In this study, we showed that using HH interaction analysis is possible to assist researchers in gaining more insight into identifying genetic risk factors for complex diseases.     

Quality monitoring of microbial contamination of cryopreserved parathyroid tissue

Cryopreservation of parathyroid tissue (PT) provides patients undergoing parathyroidectomy with an option for delayed autologous heterotopic parathyroid transplantation. A standard protocol for quality monitoring of PT has not been established. This article describes a method for detecting the presence of bacterial contamination in PT tissue intended for autologous transplantation. PT was received in the tissue bank, processed under aseptic conditions, and placed into cryopreservation medium. Sterility testing was performed at 2 time points prior to cryopreservation. From January 2005 to October 2008, 47 PT samples were cryopreserved. The following bacteria were isolated from 11 PT specimens: Staphylococcus epidermidis, Staphylococcus capitis subspecies ureolyticus, Staphylococcus lugdunensis, Bacillus pumilus, and corynebacteria (diphtheroids). 23% of PTs were contaminated at the time of collection, predominantly with indigenous bacteria. Quality monitoring using this protocol is a useful tool to identify tissues contaminated with bacteria.