Overexpression of TaHSF3 in Transgenic Arabidopsis Enhances Tolerance to Extreme Temperatures

Heat shock factors (HSFs) in plants regulate heat stress response by mediating expression of a set of heat shock protein (HSP) genes. In the present study, we isolated a novel heat shock gene, TaHSF3, encoding a protein of 315 amino acids in wheat. Phylogenetic analysis showed that TaHSF3 belonged to HSF class B2. Subcellular localization analysis indicated that TaHSF3 localized in nuclei. TaHSF3 was highly expressed in wheat spikes and showed intermediate expression levels in roots, stems, and leaves under normal conditions. It was highly upregulated in wheat seedlings by heat and cold and to a lesser extent by drought and NaCl and ABA treatments. Overexpression of TaHSF3 in Arabidopsis enhanced tolerance to extreme temperatures. Frequency of survival of three TaHSF3 transgenic Arabidopsis lines was 75–91 % after heat treatment and 85–95 % after freezing treatment compared to 25 and 10 %, respectively, in wild-type plants (WT). Leaf chlorophyll contents of the transformants were higher (0.52–0.67 mg/g) than WT (0.35 mg/g) after heat treatment, and the relative electrical conductivities of the transformants after freezing treatment were lower (from 17.56 to 18.6 %) than those of WT (37.5 %). The TaHSF3 gene from wheat therefore confers tolerance to extreme temperatures in transgenic Arabidopsis by activating HSPs, such as HSP70.     

Fruit and vegetable consumption,cardiovascular disease,and all-cause mortality in China

Science China Life Sciences - Evidence about the response patterns of fruit and vegetable consumption with the risk of cardiovascular disease (CVD) and all-cause mortality was inconsistent. These...     

Salmonella Typhimurium strain expressing OprF‐OprI protects mice against fatal infection by Pseudomonas aeruginosa

Pseudomonas aeruginosa poses a major threat to human health and to the mink industry. Thus, development of vaccines that elicit robust humoral and cellular immunity against P. aeruginosa is greatly needed. In this study, a recombinant attenuated Salmonella vaccine (RASV) that expresses the outer membrane proteins fusion OprF_190–342‐OprI_21–83 (F1I2) from P. aeruginosa was constructed and the potency of this vaccine candidate assessed by measuring F1I2‐specific humoral immune responses upon vaccination through s.c. or oral routes. S.C. administration achieved higher serum IgG titers and IgA titers in the intestine and induced stronger F1I2‐specific IgG and IgA titers in lung homogenate than did oral administration, which resulted in low IgG titers and no local IgA production. High titers of IFN‐γ, IL‐4, and T‐lymphocyte subsets induced a mixed Th1/Th2 response in mice immunized s.c., indicating elicitation of cellular immunity. Importantly, when immunized mice were challenged with P. aeruginosa by the intranasal route 30 days after the initial immunization, s.c. vaccination achieved 77.78% protection, in contrast to 41.18% via oral administration and 66.67% via Escherichia coli‐expressed F1I2 (His‐F1I2) vaccination. These results indicate that s.c. vaccination provides a better protective response against P. aeruginosa infection than do oral administration and the His‐F1I2 vaccine.     

Complete Genome Sequence of Staphylococcus aureus Bacteriophage GH15

GH15 is a polyvalent phage that shows activity against a wide range of Staphylococcus aureus strains. In this work, the complete genome sequence of GH15 was determined. With a genome size of 139,806 bp (double-stranded DNA), GH15 is the largest staphylococcal phage sequenced to date. The complete genome encodes 214 open reading frames (ORFs) and 4 tRNAs. The closest relatives are the class III staphylococcal myobacteriophages, including K, A5W, ISP, Sb-1, and G1. Interestingly, although corresponding gene sequences demonstrate very high similarity, all the introns and inteins present in the phages listed above are absent in GH15. As such, GH15 can be considered phylogenetically unique among the staphylococcal myobacteriophages, indicating the diversity of this family.     

Association of monosodium glutamate intake with overweight in Chinese adults: the INTERMAP Study

Animal studies indicate that monosodium glutamate (MSG) can induce hypothalamic lesions and leptin resistance, possibly influencing energy balance, leading to overweight. This study examines the association between MSG intake and overweight in humans. We conducted a cross-sectional study involving 752 healthy Chinese (48.7% women), aged 40-59 years, randomly sampled from three rural villages in north and south China. The great majority of participants prepared their foods at home, without use of commercially processed foods. Diet was assessed with four in-depth multipass 24-h recalls. Participants were asked to demonstrate MSG amounts added in food preparation. Amounts shaken out were weighed by trained interviewers. Overweight was defined as BMI > or =25.0 or > or =23.0 kg/m(2)(based on World Health Organization recommendations for Asian populations). Eighty-two percent of participants were MSG users. Average intake was 0.33 g/day (s.d. = 0.40). With adjustment for potential confounders including physical activity and total energy intake, MSG intake was positively related to BMI. Prevalence of overweight was significantly higher in MSG users than nonusers. For users in the highest tertile of MSG intake compared to nonusers, the multivariable-adjusted odds ratios of overweight (BMI > or =23.0 and > or =25.0) were 2.10 (95% confidence interval, 1.13-3.90, P for trend across four MSG categories = 0.03) and 2.75 (95% confidence interval, 1.28-5.95, P = 0.04). This research provides data that MSG intake may be associated with increased risk of overweight independent of physical activity and total energy intake in humans.     

Ideal cardiovascular health and incidence of atherosclerotic cardiovascular disease among Chinese adults: the China-PAR project

Existing evidence on the relationship between cardiovascular health(CVH) metrics and cardiovascular disease(CVD) was primarily derived from western populations. We aimed to evaluate the benefits of ideal CVH metrics on preventing incident atherosclerotic CVD(ASCVD) in Chinese population. This study was conducted among 93,987 adults from the China-PAR project(Prediction for ASCVD Risk in China) who were followed up until 2015. Cox proportional hazard regression models were used to estimate the hazard ratios(HRs) and their corresponding 95% confidence intervals(CIs) of CVH metrics for the risk of ASCVD, including coronary heart disease(CHD), stroke and ASCVD death. We further estimated the population-attributable risk percentage(PAR%) of these metrics in relation to each outcome. We observed gradient inverse associations between the number of ideal CVH metrics and ASCVD incidence. Compared with participants having ≤2 ideal CVH metrics, the multivariable-adjusted HRs(95% CIs) of ASCVD for those with 3, 4, 5, 6 and 7 ideal CVH metrics were 0.83(0.74–0.93), 0.66(0.59–0.74), 0.55(0.48–0.61), 0.44(0.38–0.50) and 0.24(0.18–0.31), respectively(P for trend 0.0001). Approximately 62.1% of total ASCVD, 38.7% of CHD, 66.4% of stroke, and 60.5% of ASCVD death were attributable to not achieving all the seven ideal CVH metrics. After adjusting effects of ideal health factors, having four ideal health behaviors could independently bring adults health benefits in preventing 17.4% of ASCVD, 18.0% of CHD, 16.7% of stroke, and 10.1% of ASCVD death. Among all the seven CVH metrics, to keep with ideal blood pressure(BP) implied the largest public health gains against various ASCVD events(PAR% between 33.0% and 47.2%), while ideal diet was the metric most difficult to be achieved in the long term. Our study indicates that the more ideal CVH metrics adults have, the less ASCVD burden there is in China. Special efforts of health education and behavior modification should be made on keeping ideal BP and dietary habits in general Chinese population to prevent the epidemic of ASCVD.     

Enhancement of the direct antimicrobial activity of Lysep3 against <Emphasis Type="Italic">Escherichia coli</Emphasis> by inserting cationic peptides into its C terminus

Phage lysins are considered promising antimicrobials against resistant bacterial infections. Some lysins have been reported for the prevention and treatment of Gram-positive bacterial infection. Gram-negative bacterial phage lysins, however, can only destroy the bacterial cell wall from inside because of the obstruction of the bacterial outer membrane that prevents direct hydrolysis of the bacterial wall peptidoglycan from the outside, severely restricting the development of lysins against Gram-negative bacteria. In this study, genetic engineering techniques were used to fuse a 5 cationic amino acid polypeptide (KRKRK), a 10 cationic amino acid polypeptide (KRKRKRKRKR), a 15 cationic amino acid polypeptide (KRKRKRKRKRKRKRK), and a polypeptide including both cationic and hydrophobic amino acids (KRKRKFFVAIIP) to the C-terminus of the Escherichia coli phage lysin Lysep3 to obtain four fusion lysins (5aa, 10aa, 15aa, Mix). The bactericidal effects of those four lysins on E. coli were then compared in vitro. Our results showed that the fusion of hydrophobic and positively charged amino acids, Mix, can kill E. coli effectively; the fusion of positively charged amino acids alone at the C-terminus (5aa, 10aa, 15aa) also showed bactericidal activity against E. coli from the outside, with the bactericidal activity gradually increasing with the positive charge at the C-terminus of the lysin. Collectively, improving the positive charge at the C-terminus of E. coli bacteriophage lysin Lysep3 increases its bactericidal ability from outside E. coli, providing a new practical method for the development of anti-Gram-negative bacterial lysins.     

肺炎克雷伯菌菌毛粘附素克隆表达及其对体外培养细胞的粘附活性

摘要：【目的】肺炎克雷伯菌(K.pn)与宿主细胞的粘附是致病的首要条件,粘附过程主要通过菌毛粘附素MrkD蛋白介导。为了进一步分析MrkD蛋白与宿主细胞间的粘附机制,进一步确定MrkD蛋白的粘附阻断作用。【方法】构建肺炎克雷伯菌菌毛粘附素融合蛋白原核表达质粒pGEX-4T-mrkD,转入大肠杆菌BL21,优化诱导表达条件,表达产物经亲和层析纯化、凝血酶切除融合蛋白GST标签后,进行SDS-PAGE和Western blot鉴定。激光共聚焦显微镜定位MrkD蛋白在宿主细胞上的结合部位;通过粘附活性试验与粘附动力学实验研究了MrkD蛋白的生物活性。【结果】实验得到了分子量为35 kDa的MrkD蛋白,定位了MrkD蛋白在宿主细胞上的结合部位,并证明了MrkD蛋白可以显著影响肺炎克雷伯菌对宿主细胞的粘附力。【结论】本试验首次证实了MrkD蛋白的粘附阻断作用并观察到了其与宿主细胞的作用位点,为研究肺炎克雷伯菌的致病机制,寻找粘附素功能表位奠定了基础。