Comparative growth,cross stress resistance,transcriptomics of Streptococcus pyogenes cultured under low shear modeled microgravity and normal gravity

Streptococcus pyogenes is commonly found on pharynx, mouth and rarely on skin, lower gastrointestinal tract. It is a potential pathogen causing tonsillitis, pneumonia, endocarditis. The present study was undertaken to study the effects of low shear modeled microgravity on growth, morphology, antibiotic resistance, cross-stress resistance to various stresses and alteration in gene expression of S. pyogenes. The growth analysis performed using UV–Visible spectroscopy indicated decrease in growth of S. pyogenes under low shear modeled microgravity. Morphological analysis by Bio-transmission electron microscopy (TEM), Bio-scanning electron microscopy (SEM) did not reveal much difference between normal and low shear modeled microgravity grown S. pyogenes. The sensitivity of S. pyogenes to antibiotics ampicillin, penicillin, streptomycin, kanamycin, hygromycin, rifampicin indicates that the bacterium is resistant to hygromycin. Further S. pyogenes cultured under low shear modeled microgravity was found to be more sensitive to ampicillin and rifampicin as compared with normal gravity grown S. pyogenes. The bacteria were tested for the acid, osmotic, temperature and oxidative cross stress resistances. The gene expression of S. pyogenes under low shear modeled microgravity analyzed by microarray revealed upregulation of 26 genes and down regulation of 22 genes by a fold change of 1.5.     

Development of a Efficient and Sensitive Dispersive Liquid–Liquid Microextraction Technique for Extraction and Preconcentration of 10 β2-Agonists in Animal Urine

Dispersive liquid–liquid microextraction (DLLME) coupled with ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) was developed for the extraction and determination of 10 β₂-agonists in animal urine. Some experimental parameters, such as the type and volume of the extraction solvent, the concentration of the dispersant, the salt concentration, the pH value of the sample solution, the extraction time and the speed of centrifugation, were investigated and optimized. Under the optimized conditions, a good enrichment factors (4.8 to 32.3) were obtained for the extraction. The enrichment factor show that the concentration rate of DLLME is significantly higher than other pretreatment methods, and the detection sensitivity has been greatly improved. The calibration curves were linear, the correlation coefficient ranged from 0.9928 to 0.9999 for the concentration range of 0.05 to 50 ngmL^-1 and 0.1 to 50 ngmL^-1, and the relative standard deviations (RSDs, n = 15, intra and inter-day precision) at a concentration of 5 ngmL^-1 were in the range of 1.8 to 14.6%. The limits of detection (LODs) for the 10 β₂-agonists, based on a signal-to-noise ratio (S/N) of 3, were in the range of 0.01 to 0.03 ngmL^-1. The proposed method was used to identify β₂-agonists in three types of animal urine (swine, cattle, sheep), and the relative recoveries from each matrix were in the range of 89.2 to 106.8%, 90.0 to 109.8% and 89.2 to 107.2%, respectively.     

Recent H3N2 Influenza Virus Clinical Isolates Rapidly Acquire Hemagglutinin or Neuraminidase Mutations When Propagated for Antigenic Analyses

Prior to serological testing, influenza viruses are typically propagated in eggs or cell culture. Recent human H3N2 strains bind to cells with low avidity. Here, we isolated nine primary H3N2 viral isolates from respiratory secretions of children. Upon propagation in vitro, five of these isolates acquired hemagglutinin or neuraminidase mutations that increased virus binding to cell surfaces. These mutations can potentially confound serological assays commonly used to identify antigenically novel influenza viruses.     

一种新型免疫层析技术在临床乳腺癌Her-2蛋白定量检测中的应用

建立一种靶点蛋白质快速定量检测方法。在原有侧向流动免疫层析技术的基础上,通过优化层析材料和纳米微球的均一性、改进检测区的检测方法,经逐点扫描技术,建立标准浓度曲线,以达到对临床靶点蛋白质的定量检测。以乳腺癌组织中的Her2表达为例,通过对已知浓度样品的检测,验证本技术方法的准确度大于96%。另外,以蛋白质免疫印迹作为组织中特定蛋白质检测金标准,分析临床肿瘤组织中Her2蛋白的含量,其准确率也达到95.5%,而免疫组织化学方法检测准确率仅为69.58%。新型免疫层析法检测结果与靶向治疗患者的愈后密切相关(P<0.01)。改进后的新型免疫层析方法能够准确地对临床靶点蛋白质进行定量检测,而且结合侧向流动技术的简单、快速和易用性,这种新型检测方法可以广泛应用于临床组织标本、血液标本和体液标本中靶点蛋白质的临场定量检测,在一定程度上可以替代免疫组化技术。     

Responses of Crop Water Use Efficiency to Climate Change and Agronomic Measures in the Semiarid Area of Northern China

It has long been concerned how crop water use efficiency (WUE) responds to climate change. Most of existing researches have emphasized the impact of single climate factor but have paid less attention to the effect of developed agronomic measures on crop WUE. Based on the long-term field observations/experiments data, we investigated the changing responses of crop WUE to climate variables (temperature and precipitation) and agronomic practices (fertilization and cropping patterns) in the semi-arid area of northern China (SAC) during two periods, 1983–1999 and 2000–2010 (drier and warmer). Our results suggest that crop WUE was an intrinsical system sensitive to climate change and agronomic measures. Crops tend to reach the maximum WUE (WUEmax) in warm-dry environment while reach the stable minimum WUE (WUEmin) in warm-wet environment, with a difference between WUEmax and WUEmin ranging from 29.0%-55.5%. Changes in temperature and precipitation in the past three decades jointly enhanced crop WUE by 8.1%-30.6%. Elevated fertilizer and rotation cropping would increase crop WUE by 5.6–11.0% and 19.5–92.9%, respectively. These results indicate crop has the resilience by adjusting WUE, which is not only able to respond to subsequent periods of favorable water balance but also to tolerate the drought stress, and reasonable agronomic practices could enhance this resilience. However, this capacity would break down under impact of climate changes and unconscionable agronomic practices (e.g. excessive N/P/K fertilizer or traditional continuous cropping). Based on the findings in this study, a conceptual crop WUE model is constructed to indicate the threshold of crop resilience, which could help the farmer develop appropriate strategies in adapting the adverse impacts of climate warming.     

Cell source,differentiation, functional stimulation,and potential application of human thermogenic adipocytes in vitro

Recent investigations have showed that the functional thermogenic adipocytes are present in both infants and adult humans. Accumulating evidence suggests that the coexistence of classical and inducible brown (brite) adipocytes in humans at adulthood and these adipocytes function to generate heat from energy resulting in reducing body fat and improving glucose metabolism. Human thermogenic adipocytes can be differentiated in vitro from stem cells, cell lines, or adipose stromal vascular fraction. Pre-activated human brite adipocytes in vitro can maintain their thermogenic function in normal or obese immunodeficient mice; therefore, they improve glucose homeostasis and reduce fat mass in obese animals. These key findings have opened a new door to use in vitro thermogenic adipocytes as a cell therapy to prevent obesity and related disorders. Thus, this paper intends to highlight our knowledge in aspects of in vitro human brite/brown adipocytes for the further studies.     

LINC01342 promotes the progression of ovarian cancer by absorbing microRNA-30c-2-3p to upregulate HIF3A

Ovarian cancer (OC) is a highly prevalent gynecologic malignancy and its mortality is extremely high. Therefore, the development of novel therapeutic approaches for OC is of great significance. In this study, LINC01342 was upregulated in OC tissue in the GSE38666 microarray and in tumor tissue samples collected in our center. The silencing of LINC01342 suppressed the proliferative and metastatic capacities of A2780 and HO8910 cells. Subcellular distribution assays showed that LINC01342 was mainly enriched in the cytoplasm. Subsequently, the downregulation of microRNA-30c-2-3p was proven to be the target of LINC01342. The silencing of microRNA-30c-2-3p enhanced the clonality and migratory capacity of OC cells. Moreover, the silencing of microRNA-30c-2-3p could reverse the inhibited migration and clonality in OC cells caused by LINC01342 knockdown. In addition, hypoxia-inducible factor 3 subunit α (HIF3A) was proven to be the target gene of microRNA-30c-2-3p, which was upregulated. HIF3A was negatively regulated by microRNA-30c-2-3p but positively regulated by LINC01342 in OC cells. An RNA binding protein immunoprecipitation assay showed that microRNA-30c-2-3p, LINC01342, and HIF3A could bind to argonaute RISC catalytic component 2. The overexpression of HIF3A reversed the inhibited migration and clonality in OC cells with LINC01342 knockdown. By analyzing the follow-up data from the enrolled OC patients, the LINC01342 and HIF3A levels were negatively correlated with prognosis, while the microRNA-30c-2-3p level was positively correlated with the same. In short, the upregulated LINC01342 in OC absorbs microRNA-30c-2-3p to release HIF3A. Thus, upregulated HIF3A expression accelerates the progression of OC.