叶面喷施外源物质对黄瓜商品苗贮运质量的影响

为了探究叶面喷施外源物质对黄瓜商品苗贮运质量的提升效果,研究蔬菜育苗生产中常用的寡聚糖、壮苗1号和植物益生源对贮运0、3、6 d黄瓜穴盘苗质量的影响。结果表明:与喷施清水的对照相比,壮苗1号可以抑制幼苗徒长,增加地下部干质量,维持较高的壮苗指数、比叶重和叶绿素含量,而植物益生源和寡聚糖对幼苗各生长指标的影响较小。因此,推荐叶面喷施壮苗1号来提高黄瓜商品苗的贮运质量。     

辣椒新品种博辣红星的选育

博辣红星是以05S155为母本、SJ05-22为父本配制的一代杂交种。中熟,首花节10～11节。青果深绿色,生物学成熟果深红色,果实羊角形,果表光亮。果长12～14㎝,果宽2.2～2.5㎝,肉厚0.27㎝,单果质量27g左右,味辣,色素含量高。2009—2010区域试验平均产量为1985.38㎏/667m2,生产试验平...     

Construction of mouse ESC line stably expressing Pdx1 by Tet-On system

AIM To construct the mouse embryonic stem cell （ESC） line with stable pancreatic and duodenal homeobox 1 （Pdx1） expression by Tet-On system, which may lay a foundation for further research on the differentiation of Pdx1⁺ definitive endoderm cells into pancreatic cells. METHODS The Pdx1-overexpressing lentiviral vector with green fluorescent protein marker and puromycin resistance was constructed by Tet-On system and was used to infect the mouse ESC. The cells were divided into 3 groups： blank control group （ESC group）, empty lentivirus control group （PDX1^- ESC group） and Pdx1 lentivirus transfection group （PDX1⁺ ESC group）. Flow cytometry was used to detect the transfected cells after screening by doxycycline （DOX）. The function of Tet-On system and the expression of Pdx1 gene were detected. The transfected cells in PDX1^- ESC group and PDX1⁺ ESC group were sorted by flow cytometry, and constructed ESC line with stable expression of Pdx1 and negative control ESC line were verified. RESULTS （1） The positive rates of transfected cells in PDX1^- ESC group and PDX1⁺ ESC group were 90.72% and 94.01% after screening by DOX, respectively. The positive rates of transfected cells in PDX1^- ESC group and PDX1⁺ ESC group was 97.84% and 98.13% after sorting by flow cytometry, respectively. （2） With DOX, green fluorescence was observed in PDX1^- ESC group and PDX1⁺ ESC group. The mRNA and protein expression of Pdx1 was significantly increased in PDX1⁺ ESC group （P<0.05）. Without DOX, no green fluorescence was observed in the cells of the 3 groups, and no significant difference in the mRNA and protein expression of Pdx1 was observed （P>0.05）. （3） After 3 months of cryopreservation, the cell lines still survived in resuscitation culture and were regulated by DOX. CONCLUSION Using Tet-On system, the mouse ESC line with inducible Pdx1 expression were successfully established and could be used as an effective cell model to research the differentiation of Pdx1⁺ definitive endoderm cells into pancreatic cells.     

紫花苜蓿MsCOL1基因RNAi表达载体的构建及转化

根据紫花苜蓿CONSTANS类似基因MsCOL1基因(登录号:DQ661682)序列,设计含有酶切位点的两对特异性引物,以紫花苜蓿cDNA为模板,分别合成用于构建干扰载体的正反义片段,将正反义片段分别插入表达载体pART27的相应位置,构建含有发夹结构的RNAi载体pART-S-A.利用农杆菌介导方法,将pART-S-A转化到紫花苜蓿中,经PCR检测,获得了7株转基因植株.经RT-PCR检测,证明转基因植株中MsCOL1基因表达量有所下降,其中5株的表达量明显的降低.结果表明,已构建成功具有发夹结构的RNAi载体pART-S-A,它可有效的抑制紫花苜蓿MsCOL1基因.     

Isolation and characterization of antimicrobial-resistant Escherichia coli from national horse racetracks and private horse-riding courses in Korea

Limited information is available regarding horse-associated antimicrobial resistant (AR) Escherichia (E.) coli. This study was designed to evaluate the frequency and characterize the pattern of AR E. coli from healthy horse-associated samples. A total of 143 E. coli (4.6%) were isolated from 3,078 samples collected from three national racetracks and 14 private horse-riding courses in Korea. Thirty of the E. coli isolates (21%) showed antimicrobial resistance to at least one antimicrobial agent, and four of the AR E. coli (13.3%) were defined as multi-drug resistance. Most of the AR E. coli harbored AR genes corresponding to their antimicrobial resistance phenotypes. Four of the AR E. coli carried class 1 integrase gene (intI1), a gene associated with multi-drug resistance. Pulsed-field gel electrophoretic analysis showed no genetic relatedness among AR E. coli isolated from different facilities; however, cross-transmissions between horses or horses and environments were detected in two facilities. Although cross-transmission of AR E. coli in horses and their environments was generally low, our study suggests a risk of transmission of AR bacteria between horses and humans. Further studies are needed to evaluate the risk of possible transmission of horse-associated AR bacteria to human communities through horse riders and horse-care workers.     

Concordance between Results of Medium-term Liver Carcinogenesis Bioassays and Long-term Findings for Carcinogenic 2-Nitropropane and Non-carcinogenic1-Nitropropane in F344 Rats

This study was conducted to determine the concordance of results for a pair of structural isomers, 2-nitropropane (2-NP) and 1-nitropropane (1-NP), using the rat medium-term liver carcinogenesis bioassay (Ito test) and previously published long-term carcinogenicity tests. Male F344 rats were given a single intraperitoneal injection of DEN (200 mg/kg b.w.) to initiate hepatocarcinogenesis. After 2 weeks, they received per os 0, 0.8, 4 or 20 mg/kg/day of 2-NP or 1-NP six times a week and were subjected to two-thirds partial hepatectomy at week 3. Non-initiated groups receiving 0 or 20 mg/kg/day were also included. The animals were sacrificed for quantitative analysis of GST-P-positive foci at week 8. With the highest dose of 2-NP, significantly increased numbers and areas of GST-P-positive foci were demonstrated as compared with the respective control but were not noted with 1-NP. In the non-DEN-initiated groups, many small GST-P-positive foci of less than 0.2 mm in diameter were also induced in the rats treated with 2-NP at 20 mg/kg/day but were lacking with 1-NP. These results strongly support that 2-NP is a complete hepatocarcinogen with a potent initiation activity, whereas 1-NP is not.     

18S rRNA／rDNA序列分析技术在瘤胃原虫分类学研究中的应用

作者指出了反刍动物瘤胃原虫分类学研究中的难点，介绍了原虫分类学中新兴的分子生物学指标(18S rRNA／rDNA序列同源性)，综述了18S rRNA／rDNA序列分析技术在瘤胃原虫分类研究中的应用。     

Screening of Probiotics Inhibiting E. coli K88 in vitro

The probiotics tested in the experiment were isolated from the intestinal of weaning piglets.The isolated probiotics and E.coli K88 were inoculated into the culture of intestinal porcine epithelial cell-1 (IPEC-1).The activity of lactate dehydrogenase (LDH) in the supernatant was measured after incubating for 2.5 h.At the same time, the probiotics and E.coli K88 were co-cultured in vitro, the number of E.coli K88 was counted and the probiotics which could be resistant to the E.coli K88 were selected 2.5 h later.The results showed that the Lactobacillus casei and Bacillus coagulans could significantly reduce LDH activity (P<0.05), decrease the damage of E.coli K88; Bacillus coagulans could inhibit the growth of E.coli K88.At the same time, Bacillus coagulans could resist high temperature, acid and bile salt.The results showed that Bacillus coagulans strains had great potential as the application of probiotics strains.The methods could be used as a model of screen probiotics which could inhibit the growth of E.coli K88 in vitro.     

Intra‐annual changes in reproductive indices of male and female Himalayan snow trout,Schizothorax richardsonii (Gray, 1832)

Periodic changes in reproductive hormone levels, gonadal histology and gonadosomatic index (GSI) of snow trout, Schizothorax richardsonii, were examined to ascertain annual cycle of gonadal development and reproductive status in their natural habitat. In females, there were coherent changes in plasma 17β‐oestradiol and vitellogenin along with GSI, oocyte maturation and vitellogenic progression, collectively indicating two distinct maturation peaks during the months of September and February. Coinciding with this, in males, plasma 11‐keto testosterone was also noticeably higher during September and February, with highest GSI values in September. However, plasma 17α, 20β‐dihydroxyprogesterone levels in males were found to be persistently high from September to February. This observation suggests the potential presence of matured oozing males over a longer period, unlike in females. Overall, the close association between reproductive hormone levels, GSI and gonadal maturation stages in males and females (particularly, the presence of postovulatory follicle complexes) with apparent natural synchronization clearly indicates that S. richardsonii breeds twice in a year, possibly during late September to early November and late February to early April in the coldwater riverine habitats of the Indian Himalayan region.     

和田绿洲水文气象要素分形特征与R/S分析

基于和田绿洲半个世纪（1954-2003年）以来实测水文气象资料,应用Kandell秩次相关检验法进行趋势性分析,结果表明：气温、蒸发的增加趋势显著,降水、相对湿度与河川径流量存在不显著的减少趋势。R/S分析结果表明,绿州内各水文气象要素的变化具有持续性,但不同季节的持续强度不同,降水和相对湿度的持续强度夏季大于冬季,其余表现为冬季大于夏季。分形结果显示,各水文气象要素变化的趋势性和复杂程度不同,其中玉龙喀什河径流量〉喀拉喀什河径流量〉相对湿度〉降水量〉平均气温〉蒸发量,即绿洲径流变化的趋势线最不明显,也最复杂。研究结果对了解绿洲气候资源、指导农业生产及预防灾害有参考作用。