一株产纤维素酶真菌Mucor amphibiorum RSC1的分离鉴定及其产酶培养基的初步优化

[目的]对一株产纤维素酶真菌进行分离鉴定,以期为产纤维素酶菌株种类的丰富提供试验依据。[方法]通过刚果红平板染色法初筛和摇瓶发酵产酶复筛从农田稻草堆的土壤中筛选出可产纤维素酶的真菌菌株,并对其发酵产酶培养基进行了单因素试验优化,同时对该菌进行了形态学和18S rRNA分子生物学鉴定。[结果]分离得到的菌株为1株产纤维素酶丝状真菌RSC1,发酵产酶培养基优化结果显示,培养基中含1.3%CMC-Na,0.1%酵母膏和0.1%MgSO4时其产酶活性最高。对该菌进行的形态学和分子生物学鉴定结果表明,丝状真菌RSC1与毛霉属真菌Mucor amphibiorum相似度为97%,故将该丝状真菌命名为Mucor amphibiorum RSC1。[结论]该研究鉴定了所分离纯化的菌株为Mucor amphibiorum RSC1,该结果为产纤维素酶菌株种类的丰富奠定了基础。     

Hemolytic assay for goat (caprine) and swine (porcine) complement

Optimal conditions for assaying hemolytic complement of goat (caprine) and swine (porcine) sera were determined. Effects of the following were tested: pH, ionic strength, calcium and magnesium ion concentrations, time and temperature of incubation, and ethylenediamine tetracetate concentration. Guinea pig erythrocytes sensitized with goat or cattle antibodies were the most sensitive target cells for goat complement. Sheep and cattle erythrocytes sensitized with rabbit hemolysin were the best target cells for swine complement. Barbital buffer, pH 7.3, ionic strength of 90 nmM relative salt concentration, containing 0.5 mM CaCl2 and 1 mM MgCl2 was the best for swine complement assay. Goat complement lysed best in a barbital buffer, pH 8, ionic strength of 90 to 120 mM of relative salt concentration, in presence of 0.5 mM CaCl2 and 1 mM MgCl2. The optimal incubation temperature was 37 degrees C for both complements. The complement dependent lysis required 75 minutes to reach its maximum. Ethylenediamine tetracetate in 4 mM concentration completely inhibited lysis by both species complements. The CH50 for goat sera varied between 18 and 75 per ml, in swine sera between 75 and 210 per ml.     

Characterization and allelism of soybean mosaic virus strain SC3 resistance in ‘Qihuang-1’ derived soybean cultivars

Soybean mosaic virus is a severe constraint of soybean production in China. A total of country-wide 22 SMV strains (SC1-SC22) were identified. Of these, SC3 is a major strain widely distributed in Huanghuai and Yangtze River Valley region of China. Soybean cultivar ‘Qihuang-1’ contains R_SC3Q locus conditioning the resistance to SC3 and is an important parental line extensively used to breed the soybean cultivars in China. The objective of this study was to elucidate the genetic pattern of SC3 resistance genes in cultivars developed from ‘Qihuang-1’ or its derivative lines. Hence, we have evaluated the SC3 resistance in 91 cultivars developed from ‘Qihuang-1’ or its derivative lines. The results showed that a total of 43 cultivars exhibited resistance to the SC3 strain. Among them, 37 cultivars were derived from ‘Qihuang-1’. Then, we have detected the R_SC3Q loci in these cultivars using four SSR markers (Satt334, Sct_033, BARCSOYSSR_13_1114 and BARCSOYSSR_13_1136). It revealed that, among the 37 resistant cultivars derived from ‘Qihuang-1’, there are 20 cultivars containing R_SC3Q loci. Moreover, the allelic relationship of resistance genes was analysed using the crosses from resistance × resistance between ‘Qihuang-1’ and its resistant derived cultivars. The results showed that the resistance genes of ‘Qihuang-1’ and its 20 cultivars were allelic. But it is not allelic with those of the other 17 cultivars, different from ‘Qihuang-1’, and also, R_SC3Q does not condition the resistance. These results will be beneficial to exploring the transmission of resistance genes of ‘Qihuang-1’ and will be useful to the disease resistance breeding of soybean.     

Antioxidant properties of wheat and rye bran extracts obtained by pressurized liquid extraction with different solvents

Rye and wheat brans are valuable sources of bioactive compounds, which could be used for the development and commercialization of high added value functional ingredients such as dietary antioxidants. The aim of this study was to evaluate antioxidant potential of rye and wheat bran using different polarity solvents. Cereal brans were ground to four different particle size fractions and extracted at 10.3 MPa pressure and 80 °C temperature by consecutive application of hexane, acetone and methanol:water (80:20%). The highest extract yield was obtained from rye bran using methanol-water; particle size in most cases had a significant effect. Antioxidant potential of extracts was assessed by ABTS^+•, DPPH^• scavenging, ORAC and total phenols content (TPC) assays. Extraction solvent had a major influence on TPC and antioxidant activity of the extracts. The most active extracts were obtained using methanol:water; rye bran extracts, in general, were stronger antioxidants than wheat bran extracts. For the majority of assays, reduction of particle size resulted in higher antioxidant activity values. However, ABTS^+• scavenging was found to decrease by decreasing particle size of rye bran used for extraction.     

Preparation and evaluation of antioxidant capacity of Jackfruit (Artocarpus heterophyllus Lam.) wine and its protective role against radiation induced DNA damage

Jackfruit is an underutilized edible fruit in the tropics and subtropics. The aim of this study was to produce wine from jackfruit pulp and to evaluate the total phenolic and flavonoid contents and antioxidant properties of the wine. The ability of scavenging free radicals was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant assay (FRAP), N, N-dimethyl-p-phenylendiamine (DMPD) and nitric oxide (NO) scavenging assays. Experimental results indicated that jackfruit wine was effective in DPPH radical scavenging (69.44 ± 0.34%), FRAP (0.358 optical density value, O.D.), DMPD (78.45 ± 0.05%) and NO (62.46 ± 0.45%) capacity. By the analysis of the high performance liquid chromatography coupled to diode array detector (HPLC-DAD), two phenolic compounds namely gallic acid and protocatechuic acid were identified. The jackfruit wine was also able to protect H₂O₂ + UV radiation and γ-radiation (100 Gy) induced DNA damage in pBR322 plasmid DNA. The antioxidant and DNA damage protecting properties of jackfruit wine confirmed health benefits when consumed and could become a valuable source of antioxidant rich neutraceuticals. Additionally, the wine could be a commercially valuable by-product for the jackfruit growers.     

施用脱硫石膏对稻田碱土和排水中可溶性盐分的影响

【目的】探讨不同脱硫石膏施用量对稻田碱土和排水中可溶性盐分的影响.【方法】通过田间试验,研究了脱硫石膏3个施用量29.17、16.68和4.17 t·hm-2(分别记为S1、S2、S3)对水田排水中可溶性盐分浓度的影响和苏打碱土的改良效果.【结果和结论】除碳酸根外,水稻分蘖期后水田排水中可溶性盐分的浓度趋于稳定,pH、电导率和残余碳酸钠含量(RSC)基本不变;0~20 cm耕层土壤电导率随着石膏施入量的增加而升高,S1和S2处理10~20 cm土壤的电导率存在显著差异(P0.05),pH和钠吸附比(SAR)则呈相反的变化趋势;0~40 cm土壤S1处理的脱盐效果好于S2和S3处理.