Mouse Myosin-19 Is a Plus-end-directed,High-duty Ratio Molecular Motor

Class XIX myosin (Myo19) is a vertebrate-specific unconventional myosin, responsible for the transport of mitochondria. To characterize biochemical properties of Myo19, we prepared recombinant mouse Myo19-truncated constructs containing the motor domain and the IQ motifs using the baculovirus/Sf9 expression system. We identified regulatory light chain (RLC) of smooth muscle/non-muscle myosin-2 as the light chain of Myo19. The actin-activated ATPase activity and the actin-gliding velocity of Myo19-truncated constructs were about one-third and one-sixth as those of myosin-5a, respectively. The apparent affinity of Myo19 to actin was about the same as that of myosin-5a. The RLCs bound to Myo19 could be phosphorylated by myosin light chain kinase, but this phosphorylation had little effect on the actin-activated ATPase activity and the actin-gliding activity of Myo19-truncated constructs. Using dual fluorescence-labeled actin filaments, we determined that Myo19 is a plus-end-directed molecular motor. We found that, similar to that of the high-duty ratio myosin, such as myosin-5a, ADP release rate was comparable with the maximal actin-activated ATPase activity of Myo19, indicating that ADP release is a rate-limiting step for the ATPase cycle of acto-Myo19. ADP strongly inhibited the actin-activated ATPase activity and actin-gliding activity of Myo19-truncated constructs. Based on the above results, we concluded that Myo19 is a high-duty ratio molecular motor moving to the plus-end of the actin filament.     

Evaluation of Stratiolaelaos scimitus and Neoseiulus barkeri for biological control of thrips on greenhouse cucumbers

Stratiolaelaos scimitus Berlese (Acari: Laelapidae) is an important soil-dwelling predatory mite used to control thrips and it is necessary to explore its potential predation capacity. In the present study, the functional response for S. scimitus on the pupae of Frankliniella occidentalis Pergande was examined. In addition, the effects of released S. scimitus for the control of Thrips tabaci Lindeman and F. occidentalis on greenhouse cucumber were evaluated, and compared with that of the common predator Neoseiulus barkeri Hughes (Acari: Phytoseiidae). The results showed that S. scimitus exhibited a Holling type II functional response on thrips pupae. The greenhouse study indicated that the release of N. barkeri and S. scimitus separately at the density of 250 mites/m² suppressed the population growth of thrips. In comparison with control plots, N. barkeri and S. scimitus reduced the population of T. tabaci by 76% and 64% in six weeks, respectively. Releases of N. barkeri and S. scimitus led to a reduction in F. occidentalis by 41% and 43%, respectively. Significantly lower densities of both thrips species per leaf were recorded in treatments of individual releases of N. barkeri or S. scimitus than that in the control plots. The findings highlight the potential for utilising N. barkeri and S. scimitus as biological control agents of T. tabaci and F. occidentalis, respectively.     

High-Dose Statin Pretreatment Decreases Periprocedural Myocardial Infarction and Cardiovascular Events in Patients Undergoing Elective Percutaneous Coronary Intervention: A Meta-Analysis of Twenty-Four Randomized Controlled Trials

Background

Evidence suggests that high-dose statin pretreatment may reduce the risk of periprocedural myocardial infarction (PMI) and major adverse cardiac events (MACE) for certain patients; however, previous analyses have not considered patients with a history of statin maintenance treatment. In this meta-analysis of randomized controlled trials (RCTs), we reevaluated the efficacy of short-term high-dose statin pretreatment to prevent PMI and MACE in an expanded set of patients undergoing elective percutaneous coronary intervention.

Methods

We searched the PubMed/Medline database for RCTs that compared high-dose statin pretreatment with no statin or low-dose statin pretreatment as a prevention of PMI and MACE. We evaluated the incidence of PMI and MACE, including death, spontaneous myocardial infarction, and target vessel revascularization at the longest follow-up for each study for subgroups stratified by disease classification and prior low-dose statin treatment.

Results

Twenty-four RCTs with a total of 5,526 patients were identified. High-dose statin pretreatment was associated with 59% relative reduction in PMI (odds ratio [OR]: 0.41; 95% confidence interval [CI]: 0.34–0.49; P<0.00001) and 39% relative reduction in MACE (OR: 0.61; 95% CI: 0.45–0.83; P = 0.002). The benefit of high-dose statin pretreatment on MACE was significant for statin-naive patients (OR: 0.69; 95% CI: 0.50–0.95; P = 0.02) and prior low dose statin-treated patients (OR: 0.28; 95% CI: 0.12–0.65; P = 0.003); and for patients with acute coronary syndrome (OR: 0.52; 95% CI: 0.34–0.79; P = 0.003), but not for patients with stable angina (OR: 0.71; 95% CI 0.45–1.10; P = 0.12). Long-term effects on survival were less obvious.

Conclusions

High-dose statin pretreatment can result in a significant reduction in PMI and MACE for patients undergoing elective PCI. The positive effect of high-dose statin pretreatment on PMI and MACE is significant for statin-naïve patients and patients with prior treatment. The positive effect of high-dose statin pretreatment on MACE is significant for patients with acute coronary syndrome.     

Conserving plant species with extremely small populations (PSESP) in China

Over the past decades, biodiversity conservation in China has achieved a number of successes. However, due to inadequate conservation policies, poor implementation and lack of financial support, wild plant species that are extremely small in population size and therefore seriously threatened have not had the attention they require. But the new concept of plant species with extremely small populations (PSESP), first promulgated in Yunnan Province, is becoming more widely accepted in China. Several national and regional-level conservation strategies and actions for conserving China’s PSESP are being implemented over the next 5 years. With this new policy framework leading the way, plant conservation in China is set to make important new advances.     

Genetic risk scores to predict the prognosis of chronic heart failure patients in Chinese Han

Chronic heart failure (CHF) has poor prognosis and polygenic heritability, and the genetic risk score (GRS) to predict CHF outcome has not yet been researched comprehensively. In this study, we sought to establish GRS to predict the outcomes of CHF. We re‐analysed the proteomics data of failing human heart and combined them to filter the data of high‐throughput sequencing in 1000 Chinese CHF cohort. Cox hazards models were used based on single nucleotide polymorphisms (SNPs) to estimate the association of GRS with the prognosis of CHF, and to analyse the difference between individual SNPs and tertiles of genetic risk. In the cohort study, GRS encompassing eight SNPs harboured in seven genes were significantly associated with the prognosis of CHF (P = 2.19 × 10^?10 after adjustment). GRS was used in stratifying individuals into significantly different CHF risk, with those in the top tertiles of GRS distribution having HR of 3.68 (95% CI: 2.40‐5.65 P = 2.47 × 10^?10) compared with those in the bottom. We developed GRS and demonstrated its association with first event of heart failure endpoint. GRS might be used to stratify individuals for CHF prognostic risk and to predict the outcomes of genomic screening as a complement to conventional risk and NT‐proBNP.     

Purification,characterization and gene analysis of a new α-glucosidase from <Emphasis Type="Italic">shiraia</Emphasis> sp. SUPER-H168

A new α-glucosidase from Shiraia sp. SUPER-H168 under solid-state fermentation was purified by alcohol precipitation and anion-exchange and by gel filtration chromatography. The optimum pH and temperature of the purified α-glucosidase were 4.5 and 60 °C, respectively, using p-nitrophenyl-α-glucopyranoside (α-pNPG) as a substrate. Ten millimoles of sodium dodecyl sulfate, Fe²⁺, Cu²⁺, and Ag⁺ reduced the enzyme activity to 0.7, 7.6, 26.0, and 6.2 %, respectively, of that of the untreated enzyme. The K _m, V _max, and k _cat/K _m of the α-glucosidase were 0.52 mM, 3.76 U mg^?1, and 1.3?×?10⁴ L s^?1 mol^?1, respectively. K _m with maltose was 0.62 mM. Transglycosylation activities were observed with maltose and sucrose as substrates, while there was no transglycosylation with trehalose. DNA and its corresponding full-length cDNA were cloned and analyzed. The α-glucosidase coding region consisted of a 2997-bp open reading frame encoding a 998-amino acid protein with a 22-amino acid signal peptide; one 48-bp intron was located. The α-glucosidase was a monomeric protein with a predicted molecular mass of 108.2 kDa and a predicted isoelectric point of 5.08. A neighbor-joining phylogenetic tree demonstrated that Shiraia sp. SUPER-H168 α-glucosidase is an ascomycetes α-glucosidase. This is the first report of α-glucosidase from a filamentous fungus that had good glycoside hydrolysis with maltose and α-pNPG, transglycosylation and conversion activity of maltose into trehalose.     

SPR实验中的噪声因素及其补偿方法研究

在SPR实验中,SPR的响应曲线会因为溶液间本体折射率差异的影响而受到很大的干扰。介绍一种惰性蛋白溶液折射率补偿法,巧妙地解决了单通道SPR仪难以消除溶液间本体折射率差异的问题。基于这种实验方法,成功地进行了金黄色葡萄球菌肠毒素B(SEB)与其羊单克隆抗体IgG的浓度梯度反应,初步实验结果表明,SPR2000型生化分析仪对SEB的检测灵敏度为1μgml,相当于3.5×10-8molL。     

白鱀豚“淇淇”性自慰行为周期的研究

观察了人工饲养条件下成年雄性白豚“淇淇”性自慰行为的表达方式及其变化周期。性自慰行为有腹部贴池底、贴池壁和阴茎外露三种主要表现形式。性自慰行为有季节性变化趋势。腹部贴池底行为全年都发生 ,贴池壁行为和阴茎外露行为有明显的春季、秋季两个高峰 ,且春季高于秋季。性自慰行为发生的周期性变化是豚性腺活动的表现形式。性自慰性行为发生的先后顺序为贴池底、贴池壁和伸出阴茎。     

Inhibition of OsSWEET11 function in mesophyll cells improves resistance of rice to sheath blight disease

Pathogen–host interaction is a complicated process; pathogens mainly infect host plants to acquire nutrients, especially sugars. Rhizoctonia solani, the causative agent of sheath blight disease, is a major pathogen of rice. However, it is not known how this pathogen obtains sugar from rice plants. In this study, we found that the rice sugar transporter OsSWEET11 is involved in the pathogenesis of sheath blight disease. Quantitative real‐time polymerase chain reaction (qRT‐PCR) and β‐d ‐glucuronidase expression analyses showed that R. solani infection significantly enhanced OsSWEET11 expression in leaves amongst the clade III SWEET members. The analyses of transgenic plants revealed that Ossweet11 mutants were less susceptible, whereas plants overexpressing OsSWEET11 were more susceptible, to sheath blight compared with wild‐type controls, but the yield of OsSWEET11 mutants and overexpressors was reduced. SWEETs become active on oligomerization. Split‐ubiquitin yeast two‐hybrid, bimolecular fluorescence complementation and co‐immunoprecipitation assays showed that mutated OsSWEET11 interacted with normal OsSWEET11. In addition, expression of conserved residue mutated AtSWEET1 inhibited normal AtSWEET1 activity. To analyse whether inhibition of OsSWEET11 function in mesophyll cells is related to defence against this disease, mutated OsSWEET11 was expressed under the control of the Rubisco promoter, which is specific for green tissues. The resistance of transgenic plants to sheath blight disease, but not other disease, was improved, whereas yield production was not obviously affected. Overall, these results suggest that R. solani might acquire sugar from rice leaves by the activation of OsSWEET11 expression. The plants can be protected from infection by manipulation of the expression of OsSWEET11 without affecting the crop yield.