The new approaches to whole genome analysis of bacteria

A range of recombinant DNA techniques now enables whole genome analysis of any bacterium to be carried out without recourse to the classical means of bacterial genetic exchange. Using enzymes which cut infrequently, such as SpeI, combined with pulsed field gel electrophoresis, a physical map of ordered fragments can be constructed. By means of cloned fragments of known genes or oligonucleotides synthesized using data from DNA or protein sequence banks, the location of individual genes on this map can be determined. We have used these techniques to study whole genome structure in three species of Pseudomonas: P. aeruginosa, P. putida and P. solanacearum.     

Combining Information from Similar Experiments: I. Statistical Issues

A general method for combining information from similar experiments is illustrated in the case where two independent experiments are designed to estimate a dose-response curve. By accounting for variability across experiments, the proposed method avoids inferential pitfalls such as extended forms of Simpson's paradox. The validity of the method is supported by seven fundamental assumptions about data from replicated experiments. In contrast, an example indicates that failing to reject a preliminary test of equal distributions is inadequate justification for pooling data from two experiments. Methods that account for the variability across experiments in terms of known covariates are also discussed.     

Ecological background of diatom functional groups: Comparability of classification systems

Functional classification based on species traits brought a revolution in community ecology, and also boosted phytoplankton and in phytobenton (diatom) research. Several studies stressed the usefulness of phytoplankton functional groups in ecological status assessment, and there is also a strong emphasis to use combined traits in ecological assessments of diatom assemblages. The Combined Eco-Morphological Functional Groups (CEMFGs) help to reveal species-environmental correlations, which can be hidden, controlling traits separately. Nowadays, there are three types of functional guild classifications simultaneously used in the literature: (i) the original classification proposed by Passy (O); (ii) Passy’s classification complemented with a separated planktic guild (P); (iii) the refined guild classification by Rimet and Bouchez, also containing the planktic guild (RB). One of the most important criteria of the combined functional groups is the well-defined ecological frame of these combined groups; thus it is vital to harmonise the classification of the taxa into guild based combined eco-morphological functional groups (CEMFGs). In this study we tested the similarities and dissimilarities of the correlations between environmental factors and CEMFGs created in the (i)-(iii) classifications. Samples were collected in 138 sampling sites on lowland rivers and streams in the Hungarian Lowland Region. Strong correlations were anticipated between the functional groups and environmental factors due to the presence of common and/or abundant planktic taxa. Our results validated the necessity of a separated planktic guild in ecological assessments of diatom assemblages. Further relevant differences between the correlations of CEMFGs-P or CEMFGs-RB and abiotic factors were hypothesised in the case of those functional groups which contained reassigned taxa with high frequency and/or abundance. Our results confirmed this hypothesis. Furthermore, the present study also highlighted the relevance of well-defined trait classification. Abundant and/or frequent taxa, which are able to change their life forms, can modify significantly the relationship between the functional group containing them and environmental factors. In the future, both field and laboratory studies should focus on revealing the circumstances, which cause the mentioned changes in traits of diatoms.     

噪声和高温对机体健康影响的复合效应

当今社会随着经济和科技的发展,多种有害职业因素往往共同存在于同一岗位。复合因素对机体健康影响的相互作用包括四种情况:协同作用、相加作用、拮抗作用和无关作用。噪声和高温作为有害的职业因素常存在于同一岗位,那么噪声复合高温对机体健康会产生怎样的影响,这两种环境因素是否存在复合效应?文献报道不一。噪声和高温联合对听觉系统、心血管系统、神经系统的影响可能表现为协同、相加、拮抗和无关作用,对呼吸系统的影响表现为拮抗作用,目前,研究结果不一致主要原因是实验条件和暴露方法的不一致。我们认为将来的研究热点集中在噪声和高温联合产生复合效应的条件及剂量反应关系研究、机制及防治措施研究,噪声和高温联合对其他系统如消化、免疫系统是否存在复合效应也值得深入研究。     

一期经后路固定联合侧前方入路病灶清除植骨融合术治疗老年下腰椎结核临床效果观察

目的：探究一期经后路固定联合侧前方入路病灶清除植骨融合术治疗老年下腰椎结核临床效果。方法：回顾性分析我院2007年1月-2010年12月收治下腰椎结核老年患者共84例,分别设立实验组和对照组。实验组42例采用后路固定联合侧前方入路病灶清除植骨融合术治疗老年下腰椎结核,对照组42例采用前路病灶清除。分别对两组一期治疗后临床效果进行观察,对患者术后腰椎局部前凸角、Oswestry障碍指数（ODI）及脊髓损伤神经功能分级标准（ASIA）分级进行客观评定。结果：实验组一期经后路固定联合侧前方入路病灶清除植骨融合术治疗老年下腰椎结核,术后腰椎局部前凸角为（8．22±1．67）°,明显优于对照组患者术后腰椎局部前凸角为（5．02±1．93）°,（P〉0．05）;实验组患者术后ODI为（21．25±3．75）％,对照组ODI为（35．72±4．15）％,实验组疗效优于对照组（P〈0．05）;实验组患者术后ASIA分级全部转化为E级。而对照组仍有7人为D级。结论：一期经后路固定联合侧前方入路病灶清除植骨融合术治疗老年下腰椎结核具有显著的临床效果,应进一步临床推广。     

Comparative proteomic profiles of the marine cyanobacterium Trichodesmium erythraeum IMS101 under different nitrogen regimes

Trichodesmium is a marine filamentous diazotrophic cyanobacterium and an important contributor of "new" nitrogen in the oligotrophic surface waters of the tropical and sub-tropical oceans. It is unique in that it exclusively fixes N(2) at daytime, although it belongs to the non-heterocystous filamentous segment of the cyanobacterial radiation. Here we present the first quantitative proteomic analysis of Trichodesmium erythraeum IMS101 when grown under different nitrogen regimes using 2-DE/MALDI-TOF-MS. Addition of combined nitrogen (NO3-) prevented development of the morphological characteristics of the N(2)-fixing cell type (diazocytes), inhibited expression of the nitrogenase enzyme subunits and consequently N(2) fixation activity. The diazotrophic regime (N(2) versus NO3- cultures) elicited the differential expression of more than 100 proteins, which represented 13.5% of the separated proteins. Besides proteins directly related to N(2) fixation, proteins involved in the synthesis of reducing equivalents and the generation of a micro-oxic environment were strongly up-regulated, as was in particular Dps, a protein related to iron acquisition and potentially other vital cellular processes. In contrast, proteins involved in the S-adenosylmethionine (SAM) cycle, synthesis of amino acids and production of carbon skeletons for storage and synthesis of amino acids were suppressed. The data are discussed in the context of Trichodesmium's unusual N(2)-fixing physiology.     

Ergosterol production from molasses by genetically modified <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

Ergosterol is an economically important metabolite produced by fungi. Recombinant Saccharomyces cerevisiae YEH56(pHXA42) with increased capacity of ergosterol formation was constructed by combined overexpression of sterol C-24(28) reductase and sterol acyltransferase in the yeast strain YEH56. The production of ergosterol by this recombinant strain using cane molasses (CM) as an inexpensive carbon source was investigated. An ergosterol content of 52.6 mg/g was obtained with 6.1 g/l of biomass from CM medium containing 60 g/l of total sugar in 30 h in shake flask. The ergosterol yield was enhanced through the increasing cell biomass by supplementation of urea to a concentration of 6 g/l in molasses medium. Fermentation was performed in 5-l bioreactor using the optimized molasses medium. In batch fermentation, the effect of agitation velocity on ergosterol production was examined. The highest ergosterol yield was obtained at 400 rpm that increased 60.4 mg/l in comparison with the shake flask culture. In fed-batch fermentation, yeast cells were cultivated, firstly, in the starting medium containing molasses with 20 g/l of total sugar, 1.68 g/l of phosphate acid, and 6 g/l of urea (pH 5.4) for 5 h, then molasses containing 350 g/l of total sugar was fed exponentially into the bioreactor to keep the ethanol level in the broth below 0.5%. After 40 h of cultivation, the ergosterol yield reached 1,707 mg/l, which was 3.1-fold of that in the batch fermentation.     

乙型肝炎疫苗-卡介苗联合疫苗动物安全性试验研究

为评价乙型肝炎疫苗-卡介苗联合疫苗的安全性,分别给豚鼠皮下注射、小鼠皮内注射乙型肝炎疫苗-卡介苗联合疫苗或卡介苗,豚鼠每2周称体重一次,观察6周,解剖检查其病理变化;小鼠也进行病理检查。结果乙型肝炎疫苗-卡介苗联合疫苗接种组和卡介苗接种组的豚鼠体重均增加,疫苗注射局部及各脏器病理改变相似;小鼠接种局部皮肤病理改变也未见差异。结论为乙肝表面抗原(HBsAg)没有促使卡介苗毒力增强,乙型肝炎疫苗-卡介苗联合疫苗接种实验鼠是安全的。     

Screening of longevity-associated genes based on a comparison between dead and surviving populations

Aim

To investigate longevity-associated genes based on a comparison between dead and surviving populations.

Methods

A total of 71 cases of dead individuals were treated as the death group, and healthy volunteers who were matched with the dead individuals based on sex and age were recruited as the survival group. Alleles of 13 CODIS STR loci were determined using the AmpFLSTR Profiler Plus PCR Amplification Kit. The cross-validation was performed based on differences between the two groups in both frequency values and ages.

Results

The frequency value of the D18S51-17 alleles was significantly higher in the dead group than in the survival group (p < 0.05), and the frequency value of the D2S1338-18 allele was statistically lower in the dead group than in the survival group (p < 0.05). The mean age of the subjects with the D2S1338-18 allele was also significantly higher than that of the subjects without D2S1338-18, and no significant difference was observed with respect to the other three alleles.

Conclusions

The results suggest that D2S1338-18 is associated with longevity.