产IAA菌株的UV和DES诱变筛选及培养条件优化

为了得到高产吲哚-3-乙酸(IAA)菌株,采用紫外(UV)诱变和硫酸二乙酯(DES)诱变的方法,对从烟草根际土壤中分离得到的一株产IAA并具有溶有机磷性状的促生菌进行诱变选育,并对获得的目标菌株的发酵培养条件进行正交优化。结果表明,菌株经UV诱变和DES诱变均能有效提高其IAA产量。诱变条件为UV(15 W,30 cm)照射1 min或2 mg·mL^-1 DES处理30 min时,得到1株高产IAA的菌株UV19,其IAA产量为33.77 mg·L^-1,是出发菌株产量的299.48%。菌株UV19经10代继代,其产IAA能力和溶有机磷性状稳定遗传。菌株UV19产IAA培养发酵优化条件为10%装瓶量、初始pH值8、培养温度25℃、接种量3%、培养时间96 h、含500 mg·L^-1色氨酸的LB培养基,优化后IAA产量高达75.47 mg·L^-1,为优化前的2.23倍。本研究结果为菌肥及生物法生产IAA提供了基础材料及技术方案。     

莫能菌素的诱变育种与高通量筛选

莫能菌素采用紫外线-氯化锂复合诱变育种,增加突变率,再用生测法进行初步筛选,以提高筛选效率。然后把两者结合运用,既提高筛选效率又提高了菌种的生产能力。     

Failure of UV irradiation to reduce blue mould infections beneficially in an experimental water handling system for pome fruit

A reduction in the number of wounds of pears and apples which developed blue mould (Penicillium expansum) infection was associated with reduced spore concentration. An experimental ultraviolet irradiation treatment of water in a fruit-handling system reduced both spore numbers and fruit rots, but not to a level which would suggest that the technique is worth pursuing to a commercial application stage.     

板栗种仁中总酚酸的提取纯化工艺研究

[目的]建立富集板栗种仁中高纯度总酚酸的方法.[方法]以没食子酸为对照品,采用分光光度法测定板栗种仁中总酚酸含量;以总酚酸含量为指标,对提取方法进行系统研究;以总酚酸的得率和精制度为考察指标,研究大孔树脂吸附纯化提取物的工艺条件及参数.[结果]用体积分数为75％的乙醇回流提取的总酚酸获得较高的提取率,通过HPD-826型大孔树脂纯化后,总酚酸得率的质量分数达到83.6％以上,体积分数为70％的乙醇洗脱液总固物中总酚酸的质量分数达到58.1％以上.[结论]采用此种提取及精制方法,可较好地提取纯化板栗种仁中的总酚酸.     

一阶导数光谱法测定沙苑子总黄酮的含量

采用一阶导数紫外分光光度法,以273 nm为检测波长,建立沙苑子(Astragalus complanatus)总黄酮的含量测定方法.结果表明,平均回收率为100.3％,RSD为0.88％.该方法简便易行,快速准确.     

紫外分光光度法测定瑞香狼毒中总香豆素类成分的含量

采用紫外分光光度法测定瑞香狼毒中总香豆素的含量,以补骨脂素为标准品,测定波长为294 nm。结果表明,补骨脂素在4～20μg/mL范围内浓度与吸光度线性关系良好(r=0.9997),精密度RSD为0.06%,稳定性RSD为0.57%,重复性RSD为2.07%,回收率为98.42%～101.34%。该方法准确、快速、重复性好,可用于瑞香狼毒中总香豆素含量的测定。     

恩拉霉素高产菌株的快速选育

为筛选恩拉霉素高产菌株,降低生产成本,以生产用Streptomyces-483为出发菌株,进行紫外-氯化锂复合诱变。以金黄色葡萄球菌为指示菌,用琼脂块法测定抑菌圈大小,筛选出84株突变株,经摇瓶初筛、复筛、5L发酵罐验证,最终获得4株高产突变株。筛选得到的4株高产突变株经稳定性考察完全适用于生产。     

Evidence of dissolved trivalent manganese in acidic forest soils

Background

Evidence of trivalent manganese (Mn³⁺) in the aqueous phase of soils is unknown so far although this strong oxidant has large environmental implications.

Aims

We aimed to modify a spectrophotometric protocol (porphyrin method) and to discriminate between Mn²⁺ and Mn³⁺ in the aqueous phase of forest soils based on kinetic modeling.

Methods

We investigated manganese speciation in 12 forest floor solutions and 41 soil solutions from an acidic forest site by adjusting pH and correcting for absorbance.

Results

The solutions showed broad ranges in pH (3.4−6.3), dissolved organic carbon (DOC, 1.78−77.1 mg C L⁻¹), and total Mn (Mn_T, 23.9−908 µg L⁻¹). For acidic solutions, a pH-buffer was added to increase the pH of the solutions to 7.5−8.0, and background absorption was corrected for colored solutions, that is, solutions high in DOC. This was done to accelerate the reaction kinetics and avoid overestimation of Mn_T concentrations. After the pH and color adjustments, the comparison of Mn_T concentrations between the porphyrin method and optical emission spectrometry showed good agreement. Trivalent Mn, which is stabilized by organic ligands, constitutes significant proportions in both forest floor solutions (10−87%) and soil solutions (0.5−74%).

Conclusions

The dissolved Mn³⁺ is present in acidic forest soils. Thus, we revise the paradigm that this species is not stable and encourage to apply the revised method to other soils.     

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。     

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.