淀粉液化芽孢杆菌β1-1,3-1,4-葡聚糖酶基因的克隆及表达

为了比较不同的表达系统对β-1,3-1,4-葡聚糖酶基因(bgl)的效果,本研究将高产β-1,3-1,4-葡聚糖酶的淀粉液化芽孢杆菌Bacillus amyloliquefaciens BS5582的bgl基因(GenBank Accession No.EU623974)克隆到3种不同的质粒载体中,即构建pEGX-4T-1-bgl、pET20b(+)-bgl和pET28a(+)-bgl重组质粒.比较了pEGX-4T-1-bgl,在不同Escherichia coli宿主中表达效果,以及pET20b(+)-bgl和pET28a(+)-bgl在E coli BL21(DE3)中的表达效果.结果表明,E. coli BL21(DE3)-pET28a(+)-bgl能够表达最高的重组β-1,3-1,4-葡聚糖酶酶活,其总酶活可达(322.0±8.8)U/mL,是出发菌在最适摇瓶发酵条件下产酶活的40.1%.对该重组菌的产酶条件进行了分析,结合IPTG和乳糖协同的诱导作用,在基础产酶培养基中产最高总酶活为(1883.3±45.8)U/mL,表明其具有良好的工业应用价值.     

The role of estrogen receptor-beta, in the early age-related bone gain and later age-related bone loss in female mice

The molecular and cellular mechanism of estrogen action in skeletal tissue remains unclear. The purpose of this study was to understand the role of estrogen receptor-beta, (ERbeta) on cortical and cancellous bone during growth and aging by comparing the bone phenotype of 6- and 13-month-old female mice with or without ERbeta. Groups of 11-14 wild-type (WT) controls and ERbeta knockout (BERKO) female mice were necropsied at 6 and 13 months of age. At both ages, BERKO mice did not differ significantly from WT controls in uterine weight and uterine epithelial thickness, indicating that ERbeta does not regulate the growth of uterine tissue. Femoral length increased significantly by 5.5% at 6 months of age in BERKO mice compared with WT controls. At 6 months of age, peripheral quantitative computerized tomography (pQCT) analysis of the distal femoral metaphysis (DFM) and femoral shafts showed that BERKO mice had significantly higher cortical bone content and periosteal circumference as compared with WT controls at both sites. In contrast to the findings in cortical bone, at 6 months of age, there was no difference between BERKO and WT mice in trabecular density, trabecular bone volume (TBV), or formation and resorption indices at the DFM. In 13-month-old WT mice, TBV (-41%), trabecular density (-27%) and cortical thickness decreased significantly. while marrow cavity and endocortical circumference increased significantly compared with 6-month-old WT mice. These age-related decreases in cancellous and endocortical bone did not occur in BERKO mice. At 13 months of age, BERKO mice had significantly higher total, trabecular and cortical bone, while having significantly lower bone resorption, bone formation and bone turnover in DFM compared with WT mice. These results indicate that deleting ERbeta protected against age-related bone loss in both the cancellous and endocortical compartments by decreasing bone resorption and bone turnover in aged female mice. These data demonstrate that in female mice, ERbeta plays a role in inhibiting periosteal bone formation, longitudinal and radial bone growth during the growth period, while it plays a role in stimulating bone resorption, bone turnover and bone loss on cancellous and endocortical bone surfaces during the aging process.     

中国结缕草属植物(Zoysia spp.)地下部分分布和形态类型的多样性

通过对分布于我国的结缕草属(ZoysiaWilld.)54份种质地下部分特点的研究,发现其地下茎分布都在15cm土层内,其中大部分在5cm深度的土层范围内(97.23%),很少达到15cm(0.29%);不定根一般可分布到40cm左右,但表层15cm内分布了不定根总量的81.62%,其下的25cm土层中分布的不定根只占不定根总量的18.38%。地下茎在10～15cm、不定根在30～40cm土层中各性状的变异都比较显著。相关分析表明,随着纬度的升高,地下茎在较深的土层(5～15cm)中分布密度有增加的趋势,而伴随着纬度升高不定根分布密度趋小。根据地下茎和不定根分布的特点,可将我国结缕草属植物地下部分划分为3大类型,即浅茎密根型、中茎密根型和深茎浅根型。     

Seasonal variations of mercury levels and human health risk in vegetables from Arid Oasis (Shihezi city), Xinjiang,Northwest China

The purpose of this study was to investigate the seasonal variations of mercury levels and human health risk in vegetables that were collected from farmland, home garden, and plastic greenhouse in summer and winter 2016 in Arid Oasis (Shihezi city), Xinjiang, Northwest China. The results showed that the levels of mercury in fresh vegetables were lower in winter (0.003–0.025 mg·kg^?1) than in summer (0.001–0.035 mg·kg^?1). Single factor pollution (P) in vegetables indicated that all vegetables were polluted in diverse levels. The exceeding rate in different vegetables was 0.00% to 88.89% in summer and 0.00% to 100% in winter compared with limits of pollutants in vegetables. The value of bio-concentration factor (BCF) revealed that the mercury absorption capacity of 10 species vegetables decreased in the following order: pea seedling > spinage > caraway > lettuces > pakchoi > celery > crowndaisy chrysanthemum > chives > spinach > shallot. The daily intake (DI) and target hazard quotient (THQ) of mercury for children (2–12 years), young adults (18–45 years), and quinquagenarian (>45 years) indicated that non-carcinogenic values were below the threshold values except one sampling sit from farmland around the industrial parks. Furthermore, the THQ of open field in summer was higher than plastic greenhouse in winter. Under the same pollution level, children had more non-carcinogenic risk than young adults and quinquagenarian.     

分娩方式对婴儿出生后一年内肠道菌群的影响

目的 探讨不同分娩方式对婴儿出生后1年内肠道菌群定植的影响.方法 选取45例新生儿为研究对象,根据分娩方式分为自然分娩组(n=27)和剖宫产组(n=18).收集婴儿出生后0(胎粪)、3、6和12个月的粪便标本,应用高通量测序技术分析肠道菌群多样性及组成.结果 与自然分娩组比较,在0个月时剖宫产组婴儿粪便标本拟杆菌门的相...     

嗜热脂肪芽孢杆菌DNA解链蛋白BstH2的纯化及性质研究

以嗜热脂肪芽孢杆菌为材料,通过ＰｏｌｙｍｉｎＰ沉淀、硫酸铵分级及ＤＥＡＥ纤维素、磷酸纤维素、Ｂｌｕｅ－Ｓｅｐｈａｒｏｓｅ、ＦＰＬＣＭｏｎｏＱ、ＦＰＬＣ Ｓｕｐｅｒｏｓｅ１２等柱层析,得到了部分纯化ＤＮＡ解链蛋白ＢｓｔＨ２。ＢｓｔＨ２具有受ＤＮＡ促进的ＡＴＰ酶活力,没类型的核酸对ＢｓｔＨ２的ＡＴＰ酶活力的促进作用没。ＢｓｔＨ２在５５℃有最高ＡＴＰ酶活力。这种活力受大肠杆菌单链ＤＮＡ结合蛋白的抑制及随     

Organoid technology and lung injury mouse models evaluating effects of hydroxychloroquine on lung epithelial regeneration

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) damages lung epithelial stem/progenitor cells. Ideal anti-SARS-CoV-2 drug candidates should be screened to prevent secondary injury to the lungs. Here, we propose that in vitro three-dimensional organoid and lung injury repair mouse models are powerful models for the screening antiviral drugs. Lung epithelial progenitor cells, including airway club cells and alveolar type 2 (AT2) cells, were co-cultured with supportive fibroblast cells in transwell inserts. The organoid model was used to evaluate the possible effects of hydroxychloroquine, which is administered as a symptomatic therapy to the coronavirus disease 2019 (COVID-19) patients, on the function of mouse lung stem/progenitor cells. Hydroxychloroquine was observed to promote the self-renewal of club cells and differentiation of ciliated and goblet cells in vitro. Additionally, it inhibited the self-renewal ability of AT2 cells in vitro. Naphthalene- or bleomycin-induced lung injury repair mouse models were used to investigate the in vivo effects of hydroxychloroquine on the regeneration of club and AT2 cells, respectively. The naphthalene model indicated that the proliferative ability and differentiation potential of club cells were unaffected in the presence of hydroxychloroquine. The bleomycin model suggested that hydroxychloroquine had a limited effect on the proliferation and differentiation abilities of AT2 cells. These findings suggest that hydroxychloroquine has limited effects on the regenerative ability of epithelial stem/progenitor cells. Thus, stem/progenitor cell-derived organoid technology and lung epithelial injury repair mouse models provide a powerful platform for drug screening, which could possibly help end the pandemic.     

施氮量和花后土壤含水量对优质强筋小麦产量和品质的影响

在防雨池栽条件下,研究了施氮量和花后土壤含水量对优质强筋小麦产量和品质的影响.结果表明,在同一施氮量条件下,表现为花后土壤含水量过高(80%～90%)或过低(40%～50%)导致穗粒数减少,千粒重降低,最终使产量降低.在同一土壤含水量下,表现为增加施氮量有利于提高穗数,但过多(300kg/hm2)或过少(150kg/hm2)施氮均不利于穗粒数和千粒重的提高,而导致减产.在同一土壤含水量下,总蛋白质、醇溶蛋白、麦谷蛋白含量及谷/醇比随着施氮量的增加而增加.在同一施氮量条件下,总蛋白质及各组分均随着土壤含水量的增加而降低,同时谷/醇比也降低.在同一施氮量下,花后土壤含水量过高(80%～90%)或过低(40%～50%)均不利于淀粉及其组分含量的提高.在同一土壤含水量下,过高(300kg/hm2)或过低(150kg/hm2)施用氮肥均不利于淀粉及其组分含量的提高.只有保持适宜的花后土壤含水量和施适宜的氮肥才有利于支/直比的提高.适量增施氮肥或花后土壤含水量适宜可提高小麦的加工品质.这说明在小麦生产中可以通过施用氮肥和控制花后土壤水分含量技术,调控小麦品质和产量的形成,从而实现优质高产.     

Expression of hematopoietic inhibitory factors in mouse fibroblasts,macrophages and endothelial cells

Pure bone marrow fibroblasts, macrophages and endothelial cells were cultured in Iscove-modified Dulbecco's medium. RT-PCR was used to determine the expression of inhibitory cytokine mRNAs in these cell types. Serum-free conditioned medium was collected from each cell type and ultrafiltration was performed with a centriprep 10. The retentate contained substances whose molecular weights were >10 kD, whilst the filtrate contained substances with molecular weights <10 kD. The effect of conditioned media and their components on colony forming unit-granulocyte-macrophage (CFU-GM) were investigated. The results showed: (1) six cytokines, MIP-1alpha, MIP-2, TGF-beta, TNF-alpha, IFN-gamma and Tbeta(4), inhibited the growth of CFU-GM when murine WEHI-3 conditioned medium was added to the culture system as a source of colony stimulation. (2) The original endothelial cell conditioned medium (E-CM) did not affect the production of CFU-GM, but the >10 kD component of E-CM increased its production, and the <10 kD component decreased it. Both fibroblast conditioned medium (F-CM) and the >10 kD component of F-CM stimulated proliferation of CFU-GM, but the <10 kD component suppressed it. All three components of macrophage conditioned medium (M-CM) inhibited the growth of CFU-GM. (3) Expression of four of the mRNAs, namely MIP-2, TNF-alpha, INF-gamma and Tbeta(4), was seen in all three types of stromal cells, while TGF-beta mRNA was only seen in endothelial cells and macrophages, and MIP-1alpha mRNA in endothelial cells and fibroblasts. The inhibitors TGF-beta, MIP-1alpha, and Tbeta(4)have an inhibitory effect on the growth of CFU-GM, but TNF-alpha, INF-gamma and MIP-2 do not.