紫外分光光度法测定淫羊藿中总黄酮的含量

[目的]中药淫羊藿中总黄酮的含量测定。[方法]试验采用紫外分光光度法,以淫羊藿苷为对照品,以无水甲醇作空白对照,在270 nm波长处测定吸光度,计算总黄酮含量。[结果]淫羊藿苷浓度在1.68~10.08μg/ml范围内与吸光度的线性关系良好,R=0.999 4,总黄酮的平均回收率为100.36%,RSD为1.16%,淫羊藿中总黄酮的含量为(8.09±0.01)%。[结论]采用紫外分光光度法测定淫羊藿总黄酮的含量,操作快速,简便,准确。     

三芳胺基D-A结构化合物的溶致变色行为研究

研究了3个系列D-A结构化合物在5种不同极性溶剂中的荧光发射光谱及紫外吸收光谱,探讨了化合物的溶致变色规律,结果表明:3个系列化合物在不同极性溶剂中的荧光发射波长发生明显位移,在甲醇中发射波长最大,在环己烷中最小,但在二氧六环、四氢呋喃、二氯甲烷中,随着溶剂极性逐渐减小,发射波长发生红移;在不同极性溶剂中的荧光强度也各不相同,其中,在环己烷中最大,在甲醇中最小。化合物的紫外吸收波长受溶剂极性的影响,均在甲醇中有最小吸收波长,在不同极性溶剂中化合物的吸光度也不相同,在甲醇及环己烷中的吸光度较大。3个系列化合物均具备作为荧光分子探针探测外部环境极性大小的潜能。     

Individual polyphenolic profiles and antioxidant activity in sorghum grains are influenced by very low and high solar UV radiation and genotype

Sorghum is becoming more widely recognised around the world as a valuable crop for its polyphenol antioxidant health-promoting properties and adaptation to harsh environments. The antioxidant capacity of diverse polyphenols in sorghum grain can vary with climatic conditions and genotype. To explore this further, the potential role of UV radiation on the profile and concentration of polyphenols was investigated in six diverse sorghum genotypes in a controlled environment facility using natural UV and visible radiation under either UV-transmitting or UV-blocking treatments. The polyphenol content and antioxidant activity were significantly reduced under the UV-blocking treatment, with contents of individual polyphenols differing among the genotypes. This information is valuable for sorghum breeders enabling them to select genotypes and UV growth conditions to produce sorghum grain with target levels of polyphenols and antioxidant capacity for human foods to meet the nutritional and health needs of different consumers.     

In UV‐B Irradiated Rice High Levels of Mn Limits Chloroplasts Injury Triggered by Oxidative Stress

The molecular mechanism to control the oxidative burst exerted by Mn accumulation in rice (Oryza sativa L.) plants, grown in hydroponics containing 0.5, 2 and 8 mg l^–1 Mn and irradiated with a total biological effective UV‐B irradiation of 20.825 kJ m^?2, was investigated in the chloroplasts at the 15th and 21st days after germination. In both experimental periods, Mn accumulation kinetics in the leaves and in the chloroplast lamellae displayed overall increases. Coupled to higher membrane selectivity, superoxide production and acyl lipids peroxidation in the thylakoids decreased, prompting upper rates of the Hill and Mehler reactions. Connected to UV‐B irradiation, higher accumulated Mn in thylakoids was found to be chelated in a 36.5 kDa protein, with Mn/protein ratio of about 1 and high content of Gln, Asp, Glu, Leu and Gly, being its EPR spectrum characteristic of high‐spin Mn(II), in a S = 5/2 ground state. As this protein exhibited enzymatic catalysis of superoxide dismutation, it was concluded that, under UV‐B irradiation, the high internal tolerance of Oryza sativa L. to Mn during the vegetative growth also triggers the synthesis of a manganese protein that mimics superoxide dismutase functioning, therefore furnishing an additional intimate protection against oxidative stress.     

Induction of meiotic gynogenesis in bagrid catfish (Pseudobagrus ussuriensis) with homologous sperm and its confirmation for female homogamety

The bagrid catfish, Pseudobagrus ussuriensis, exhibits significant sexual dimorphism in growth rate and body size with males growing faster than females. Therefore, an all‐male culture can dramatically increase the output and profitability of fishery products. According to the monosex breeding route, super‐male individuals’ acquirement by XY male sex reversal and artificial gynogenesis is the key step. An effective protocol to induce meiotic gynogenesis using homologous sperms has been developed in this study. The most effective UV irradiation for sperm genetic inactivation was found to be at a distance of 20 cm with 66 μW/cm² light intensity for 25 min. Optimal treatment for cold shock was 5 min post‐fertilization at 0‐4°C for 30 min, which gave the best survival rate of 13.65 ± 2.87%. The sex ratio in the meiotic gynogens showed a significant female‐biased deviation (p < .05); thirty meiogynogens and their parents were further analysed using a male‐specific AFLP marker, of which only the male parent produced a male‐specific DNA band of 412 bp. These results indicated the female homogametic XX/XY sex determination system in P. ussuriensis. The optimization of a protocol for the successful induction of meiogynogenesis in the bagrid catfish lays the basis for all‐male production and is useful in ascertaining the genetic sex determination system in this promising aquaculture species.     

Inactivation of Piscine orthoreovirus

Piscine orthoreovirus infects various salmonid fish species, and the infection is associated with diseases such as heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). There are no vaccines available or genetically selected resistant hosts that can efficiently control piscine orthoreovirus (PRV) infection. Currently, the only prophylactic measure against PRV is general biosecurity measures aiming to break the transmission cycle. Methods to eradicate infectious virus from contaminated facilities are desirable, but the knowledge on how to inactivate PRV is lacking. A major bottleneck for inactivation studies is the lack of ability to propagate PRV in cell culture. Therefore, in this study we developed an in vivo model for detection of infectious PRV particles after treatment of the virus with inactivation tools such as heat, pH, iodine, UV and commercially available disinfectants. The results show that standard iodine treatment is efficient in inactivation of the virus, and similarly are high and low pH extremes and treatment with Virocid, a commercially available disinfectant. A UV dose of at least 50 mJ/cm² is required for inactivation, and the virus has high resistance against heat treatment.     

UV辐射对植物多酚代谢的影响

植物多酚是紫外线防御物质,是植物体中重要的次生代谢产物,参与植物的生长发育,赋予植物抗紫外线、抗病害等生理功能。紫外线辐射作为一种逆境因子,与植物多酚间存在着相互制约而又相辅相成的关系。文章综述了植物多酚的合成途径,着重阐述了紫外线辐射对植物生长发育及贮藏品质、植物多酚的种类及含量以及多酚合成相关基因表达的影响,旨为揭示植物多酚合成与紫外辐射的关系及调控植物多酚合成提供更多信息。     

以脂肪酶活为指标快速筛选吉他霉素高产菌株的研究

[目的]筛选吉他霉素高产菌株。[方法]以1株北里链霉菌Zn14-05为出发菌株,进行紫外线与NTG复合诱变处理,通过以脂肪酶活力为初筛指标和摇瓶复筛筛选吉他霉素高产菌株。[结果]摇瓶发酵效价比出发菌株提高10%;传代试验结果表明其遗传性能稳定。[结论]以高脂肪酶活性为初筛指标选育吉他霉素高产突变株,缩短了选育周期,减少了初筛工作量,提高了选育效率。     

国内外木材耐光老化技术研究现状

木材在户外利用时,进行耐光老化处理可以有效提高木材制品的使用寿命。文中主要从木材涂饰处理和化学改性2个方面对木材耐光老化处理技术进行较为系统、全面的介绍,分析了无机紫外吸收剂、有机紫外吸收剂、木蜡油、化学改性及抗氧化剂等方法的优缺点。未来的耐光老化技术应主要满足以下几点:价格便宜,处理容易,低毒环保,紫外线屏蔽性能好,不损害木材表面性能及涂料涂饰性能;应主要开发多组分复配涂料以满足上述要求,克服单组份耐光老化技术的不足。     

阿特拉津在紫外-氯消毒中的转化特性及机理研究

采用紫外-氯消毒技术去除水中的农药类内分泌干扰物阿特拉津,利用高效液相色谱（HPLC）测定水中阿特拉津残留浓度,并以液相-质谱联用（LC-MS、LC-MS/MS）技术鉴定其消毒副产物。结果表明,紫外-氯联合消毒技术能有效去除水中的阿特拉津。阿特拉津在紫外消毒过程中迅速降解,主要表现为脱氯羟基化作用,主要产物为2-羟基-4-乙胺基-6-异丙胺基-1,3,5-三氮苯（OIET）,次要反应为氨基侧链脱烷基、氧化以及脱水成烯反应。后续加氯过程对阿特拉津及其主要产物没有明显的去除效果,但能有效去除乙烯胺类产物,且不明显引入消毒副产物,是一种安全有效的水处理工艺。