Production of Transgenic Anliucheng Sweet Orange (Citrus sinensis Osbeck) with Xa21 Gene for Potential Canker Resistance

Citrus canker, an epidemic quarantine disease caused by Xanthomonas axonopodis pv. citri, has brought a great damage in citrus production worldwide. Herein, a rice PRR (pattern recognition receptor) gene Xa21 together with GUS reporter gene and hygromycin phosphotransferase gene (HPT) was introduced into Anliucheng sweet orange (Citrus sinensis Osbeck) via Agrobacterium-mediated transformation of embryogenic callus. The transgenic calluses were screened on MT basal medium containing hygromycin (HYG) and detected by histochemical GUS staining. The transgenic plantlets were recovered through somatic embryogenesis pathway. The regenerated plantlets were accustomed to and maintained in the greenhouse. The transgene integration of recovered plantlets was identified by PCR and Southern blot hybridization. It showed that all the transgenic plantlets tested had undergone single copy integration, the expression of Xa21 in eight different transgenic lines detected by qRT-PCR can be divided into three grades, high for T5 and T6, middle for T4 and low for the rest. The tolerance to citrus canker disease of the three recovered transgenic lines T2, T4 and T6 was assessed by in vitro pin-puncture inoculation. The results showed that all the three transgenic lines conferred improved resistance to citrus canker bacterium infection and the T4 transgenic line displayed the highest resistance. The mechanism and feasibility of rice Xa21 in triggering innate immunity in citrus was briefly discussed.     

Expression level of the cytochrome P450c21 (CYP21) protein correlating to drip loss in pigs

Drip loss is an important meat quality trait of fresh meat affecting economic losses. The cytochrome P450c21 (CYP21) protein has a role on cortisol production and depends on stress. This might affect meat quality. The present study aimed to investigate the expression of CYP21 protein in correlation with drip loss. The samples were taken from the Longissimus dorsi muscle to evaluate drip loss (n = 300). Five muscles per group (low and high drip loss) were selected to evaluate CYP21 protein expression levels. Statistical analysis revealed that CYP21 protein expression levels were significantly difference between the drip loss groups. The high drip loss group had higher CYP21 protein expression levels than the low drip loss group (P < 0.05). Moreover, the high drip loss group had higher optical density values of the CYP21 protein band than the low drip loss group (P < 0.05). In conclusion, the expression of CYP21 protein will provide the basis for information and better understanding of the mechanisms related to drip loss in pork. Further study is warranted to validate these results in other populations.     

Taq DNA聚合酶的热纯化制备（摘要）

[目的]提高Taq DNA聚合酶的制备效率。[方法]利用Ni柱亲和色谱纯化载有6xHis标记的Taq DNA聚合酶,并重组载体,利用Taq DNA聚合酶的耐热特性,对粗提液75℃处理1h,之后通过PCR试验验证制备酶液的活力。[结果]所获重组的pET-32A-Taq能够在BL21（DE3）宿主菌中高效表达并可通过热变性去除杂蛋白,获得了活力远高于购买的Taq DNA聚合酶的酶制剂。[结论]使用热纯化法制备的Taq DNA聚合酶工艺简单,成本较低,能满足常规大量PCR实验要求。     

用乙基环丙沙星重建受大肠杆菌污染的BHK-21细胞

为重建受大肠杆菌污染的BHK-21细胞,本研究采用药物乙基环丙沙星,先测出该药对大肠杆菌的最低抑制浓度(minimum inhibitory concentration,MIC),再测出该药对BHK-21细胞的MIC,从而确定10 mg/L为乙基环丙沙星不影响细胞生长,又能抑制大肠杆菌的安全浓度。然后用含该浓度乙基环丙沙星的MEM生长液,对受污染的BHK-21细胞进行物理、化学相结合的循环处理。经过3次循环处理,再传3代后,确认大肠杆菌污染已经被彻底清除,细胞恢复了健康。此方法为抢救受细菌污染的细胞提供了参考。     

转化GmWRKY21基因提高大豆耐低温性的研究

利用农杆菌介导的带一片子叶的胚尖转化法将耐低温相关转录因子基因GmWRKY21转入‘浙春5号’和‘中黄13’两个大豆品种中,以探讨通过转基因手段创造耐低温种质的可能性。转基因植株经目的基因的PCR检测和转化T-DNA区域构建特异性的PCR检测得以确认。转基因植株较非转基因对照表现出明显的耐低温性：胁迫处理前和处理后转基因植株相对电导率均显著低于对照植株;在恢复生长以后,转基因植株均能正常生长、开花、结荚,而非转基因对照在处理后的7～10 d内枯萎死亡。试验结果初步表明GmWRKY21基因已经成功导入大豆基因组中并参与了对低温的胁迫应答,进而提高了大豆的抗低温胁迫能力。     

Diagnostic value of serum miR-21 for diabetic nephropathy

AIM:To evaluate the diagnostic value of serum miR-21 as a molecular biomarker in the patients with diabetic nephropathy (DN). METHODS:Twenty-five patients with DN, 50 patients with type II diabetes ［divided into DMA group and DMB group base on urinary microalbumin (UmAlb), 25 in each group］, 25 patients with diabetic nephropathy-induced uremia (UM) and 25 normal controls (NC) were included in the study. Total RNA was extracted from the serum samples for determining the miR-21 level using real-time PCR. The relationship between miR-21 level and clinical parameters of the patients with diabetic nephropathy was analyzed. RESULTS:The relative expression level of serum miR-21 was significantly lower in DN group than that in DMA group, DMB group and NC group, and was significantly higher than that in UM group (all P<001). The serum miR-21 level showed significant negative correlation with cystatin C, UmAlb, UmAlb/urinary creatinine in DN patients (P<0.01,P<0.05,P<0.05). For discriminating the DN patients from NC, DMA, DMB, DMA＋NC, DMB＋NC and DMA＋DMB, the areas under the receiver operating characteristic curve (AUC-ROC) for serum miR-21 were 0848 (95% CI: 0737~0959), 0896 (95% CI: 0812~0980), 0782 (95% CI: 0641~0922), 0838 (95% CI: 0743~0933), 0796 (95% CI: 0675~0917) and 0808 (95% CI: 0704~0911), and the sensitivity and specificity were 800% and 720%, 720% and 880%, 720% and 840%, 760% and 770%, 760% and 820%, 700% and 860%, respectively. For discriminating the DN patients from DMA＋DMB＋NC, the AUC-ROC was 0845 (95% CI: 0752~0939), and the sensitivity and specificity were 760% and 773%, respectively. CONCLUSION: Serum miR-21 can serve as a molecular diagnostic marker for diagnosis of diabetic nephropathy.     

Changes in carbohydrate and nitrogenous components and amylase activities during germination of grain amaranth

Grain amaranth (Amaranthus hypochondriacus), Yercaud local variety, was soaked overnight and germinated for 192 h taking the soaked grains as the zero time (0 h) sample. The changes in the activities of - and -amylases, starch, sugar, protein and lysine contents during germination are reported. Activity of -amylase was high in the 0 h soaked grains, while -amylase activity was high in 72 h germinated grains. The joint action of the amylases resulted in a decrease of starch content from 0 to 192 h in germinated grains and an increase in total sugars during the initial period of germination.Protein nitrogen was found to decrease from 48 h to 192 h accompanied by an increase in free amino acid and non-protein nitrogen contents. Total lysine content was found to be increased by 31% in 24 h germinated grain amaranth. Protein fractionation of raw, soaked and 24 h germinated grain amaranth showed that the distribution of different types of proteins varied during germination of the grains. An increase of water soluble protein content was noticed in 24 h germinated grains.     

一种简便高效的PCR辅助选择技术在杂交水稻转Xa21基因育种中的应用

介绍了一种在杂交水稻转Xa21基因育种中使用的PCR分子标记辅助选择技术.该技术结合测交和半粒种子法可以快速准确地筛选出转Xa21基因纯合株系和转[ WTBX〗Xa21基因杂交稻,大大提高育种效率,对培育抗白叶枯病杂交稻具有重要的应用价值.     

晋谷21号米质与外界因素关系的研究

在不同生育期、不同降雨量、不同海拔、不同肥料等条件下种植优质谷晋谷21号，研究其小米的品质变化规律，结果表明：多降雨、高海拔、长生育期、多施富含P的农家肥，使小米色泽黄、品质优、粘糊性强、适口性好。小米的重要糊化参数峰值粘度、热糊粘度、冷糊粘度和冷糊变稠值高的有关因素是降雨少，生育期短，单施N肥，说明蛋白质含量增高其淀粉某些特殊成分影响了成糊性。     

鲁麦21慢白粉病抗性基因数目和遗传力分析

以多年鉴定具有慢白粉抗性的小麦品种鲁麦21和感白粉病品种京双16及其杂交组合F_2:3和F_2:4代株系200个为材料, 于2005—2007年连续2个生长季, 在北京和安阳两地分别进行田间病害鉴定, 并采用质量性状和数量性状2种分析方法估算鲁麦21的慢病基因数目和遗传力。结果表明, 在这2个群体中至少存在4对抗性基因, 其广义遗传力为0.53~0.78。由于出现超亲分离, 因此推测京双16可能贡献1对微效抗病基因, 而鲁麦21至少含有3对慢白粉病抗性基因。