黄精褐斑病的病原生物学特性

为明确发生在贵州省施秉县的黄精叶斑类病害的病原菌,通过形态学和分子生物学方法对病原菌进行了鉴定,并对其生物学特性进行了初步研究。形态特征及rDNA-ITS、β-tubulin和tef1多基因序列分析表明,该病原菌为棕榈拟盘多毛孢Pestalotiopsis trachicarpicola。生物学特性研究结果表明,该菌菌丝体适宜生长温度为15-30℃,最适温度为28℃;最适pH值为5;以葡萄糖为碳源、酵母浸膏为氮源比较适合菌丝体的生长;菌丝体生长的最佳培养基为PDA;光照对菌丝体生长无明显影响;菌丝体致死温度为45℃。     

Interaction between GAMs and Mean Flow Shear During SMBI Injection into HL-2A Tokamak

Plasma Physics Reports - The interactions among geodesic acoustic modes (GAMs), mean flow, and mean flow shear were investigated using Langmuir probe arrays under periodic supersonic molecular beam...     

四倍体异育银鲫新品种长丰鲫肌肉品质和营养成分分析

研究对长丰鲫、彭泽鲫、异育银鲫D系以及红鲫的肌肉品质和营养成分进行了对比分析。结果显示:肌纤维密度方面, 单位面积肌纤维密度长丰鲫最高[(184.2624.11) fiber/mm2], 其次为彭泽鲫[(149.7212.51)fiber/mm2]、异育银鲫D系[(134.4515.96) fiber/mm2]和红鲫[(119.8522.86) fiber/mm2]。粗蛋白含量、总氨基酸和呈味氨基酸方面, 长丰鲫、彭泽鲫和异育银鲫D系无明显区别。高度不饱和脂肪酸中(n3), 长丰鲫含量最高(24.2%), 依次为彭泽鲫(14.4%), 异育银鲫(11.3%)和红鲫(8.3%)。在高度不饱和脂肪酸中, 二十二碳六烯酸(DHA)长丰鲫含量最高(10.3%), 依次为红鲫(4.9%)、彭泽鲫(4.5%)和银鲫(2.9%); 花生四烯酸(AA)长丰鲫含量最高(8.3%), 依次为彭泽鲫(5.1%)、银鲫(3.8%)和红鲫(0.6%)。结果表明, 长丰鲫新品种在所检测的肌肉品质和营养成分指标方面, 优于彭泽鲫、异育银鲫D系和红鲫。     

利用甲硝唑及外加氧方法筛选耐氧产氢Klebsiella oxytoca HP1突变菌株

摘氢酶是生物制氢的关键酶,大多数氢酶因对氧极敏感而易失活,因此提高氢酶的氧耐受性对生物制氢有重要意义。本研究利用1％甲基磺酸乙酯对Klebsiella oxytoca HPl进行了两轮诱变,经40mmol／L甲硝唑和21％氧联合处理1h（第一轮诱变）或2h（第二轮诱变）进行筛选。所得突变菌株经产氢测试,结果在15％氧浓度条件下,第一代突变菌株HPl-A15产氢活性为出发菌株Klebsiella oxytoca HPl的3.70倍,在21％氧浓度条件下第二代突变菌株HPAl5-37产氢活性为HPl-A15菌株的2.75倍,是出发菌株的11倍。突变菌株HPl-A15和HPAl5-37具有较好的遗传稳定性。本试验结果说明利用MNZ和外加氧的方法适用于兼性厌氧菌耐氧产氢突变菌株的筛选。     

Detection and Quantification of Fusarium oxysporum f. sp. niveum Race 1 in Plants and Soil by Real-time PCR

Fusarium wilt caused by Fusarium oxysporum f. sp. niveum (Fon) is the most serious soil-borne disease in the world and has become the main limiting factor of watermelon production. Reliable and quick detection and quantification of Fon are essential in the early stages of infection for control of watermelon Fusarium wilt. Traditional detection and identification tests are laborious and cannot efficiently quantify Fon isolates. In this work, a real-time polymerase chain reaction (PCR) assay has been described to accurately identify and quantify Fon in watermelon plants and soil. The FONRT-18 specific primer set which was designed based on identified specific sequence amplified a specific 172 bp band from Fon and no amplification from the other formae speciales of Fusarium oxysporum tested. The detection limits with primers were 1.26 pg/μl genomic DNA of Fon, 0.2 pg/ng total plant DNA in inoculated plant, and 50 conidia/g soil. The PCR assay could also evaluate the relationships between the disease index and Fon DNA quantity in watermelon plants and soil. The assay was further used to estimate the Fon content in soil after disinfection with CaCN₂. The real-time PCR method is rapid, accurate and reliable for monitoring and quantification analysis of Fon in watermelon plants and soil. It can be applied to the study of disease diagnosis, plant-pathogen interactions, and effective management.     

Generation of virus‐resistant potato plants by RNA genome targeting

CRISPR/Cas systems provide bacteria and archaea with molecular immunity against invading phages and foreign plasmids. The class 2 type VI CRISPR/Cas effector Cas13a is an RNA‐targeting CRISPR effector that provides protection against RNA phages. Here we report the repurposing of CRISPR/Cas13a to protect potato plants from a eukaryotic virus, Potato virus Y (PVY). Transgenic potato lines expressing Cas13a/sgRNA (small guide RNA) constructs showed suppressed PVY accumulation and disease symptoms. The levels of viral resistance correlated with the expression levels of the Cas13a/sgRNA construct in the plants. Our data further demonstrate that appropriately designed sgRNAs can specifically interfere with multiple PVY strains, while having no effect on unrelated viruses such as PVA or Potato virus S. Our findings provide a novel and highly efficient strategy for engineering crops with resistances to viral diseases.     

The effect of HMGB1 A box on lung injury in mice with acute pancreatitis

The objective of this study is to observe the effect of high-mobility group protein B1 A Box (HMGB1 A) box on lung injury in mice with acute pancreatitis and its effect on the level of high-mobility group protein B1 (HMGB1) in lung, to explore the mechanism. A total of 60 male Institute of Cancer Research mice were randomly divided into control group (n = 30) and treatment group (n = 30). Severe acute pancreatitis mice model was induced by 20% L-Arg intraperitoneal injection. The recombination HMGB1 A box was used in treatment after modeling. All the mice were killed under anesthesia at 24 and 48 h after the modeling injection. The level of HMGB1 and activity of myeloperoxidase (MPO) in lung were measured. The pathological changes of lung were observed. The level of HMGB1 in lung of A box treatment group decreased more significantly 24 h and 48 h after modeling compared with control group. The activity of MPO in lung of A box treatment group decreased more significantly 24 h after modeling compared with control group. The lung tissue pathologic score of A box treatment group decreased more significantly 48 h after modeling compared with control group. HMGB1 expression levels in the lungs were positively related to histological score of injured lung in acute pancreatitis. It indicates that HMGB1 A box is remarkably protective to lung injury induced by acute pancreatitis.     

粤北蚁狮生态学的初步研究

根据多年来对粤北蚁狮的调查和试验,研究了粤北自然界穴蚁蛉的生活史,蚁狮４种生境类型,５目数十种昆虫食物分布和坐等式的捕食方式．结果表明,在一定范围内,饲食量一定时,饲食频率增大１倍,蚁狮个体发育历期缩短２０％,３５天内幼虫结茧化蛹率提高４１．７５％．