海萝凝集素的分离纯化及性质

海萝(Gloiopeltis furcata)经PBS缓冲液抽提、硫酸铵分级、DEAE-52纤维素离子交换层析和SephadexG-200分子筛层析，从中纯化出海萝凝集素(GFL)，在PAGE和等电聚焦电泳上各显示单一蛋白染色带，其等电点为9．0。用SephadexG-200分子筛层析测得其相对分子质量为8318。海萝凝集素除对人血型红细胞无凝集活性外，对单胞藻及兔、鲤、鲫的红细胞均表现出一定程度的凝集活性，对兔红细胞的凝集活性最强，且不被已测试的D-果糖、D-半乳糖、葡萄糖、蔗糖、乳糖所抑制，而被D-甘露糖、牛甲状腺球蛋白、鸡卵白蛋白、γ-球蛋抑制。该凝集素在pH4．0～10．2均有活性，而在pH6．5～9．1时活性较高。该凝集素在90℃加热1h，活力并未减弱，说明这种凝集素具有很强的耐热性。     

Isolation and characterization of strains of Flavobacterium columnare from Brazil

Flavobacterium columnare is an important pathogen of freshwater fish, implicated in skin and gill disease, often causing high mortality. An outbreak of skin disease in fingerling and adult Nile tilapia, Oreochromis niloticus (L.), cultivated in a recirculation system, was investigated. Four strains were isolated and characterized by biochemical reactions, enzyme production, fatty acid profile and analysis of the 16S-23S rDNA intergenic spacer region. All strains were identified as F. columnare. Experimental infection assays with one of these strains (BZ-5-02) were conducted and pathogenicity (by intramuscular route) was demonstrated in Nile tilapia and channel catfish, Ictalurus punctatus (Rafinesque). This is the first report of characterization of Brazilian strains of F. columnare.     

WSSV蛋白酶性质的研究

从感染白斑综合症病毒(Whitespotsyndromevirus,WSSV)的对虾中提取和纯化WSSV,对其蛋白酶活力进行分析。结果表明,WSSV蛋白酶具广泛的pH稳定性,当pH达7.5时,蛋白酶活性最大;pH高于10 0时,酶活力很低,其蛋白酶偏碱性。丝氨酸蛋白酶抑制剂苯甲基磺酰氟(PMSF)对酶活性有抑制作用。Ca2 、Mn2 、Fe2 和Cu2 可降低WSSV蛋白酶活性,但Mg2 有轻微的激活作用。胰蛋白酶抑制剂在浓度为12.5～25.0mg/L时,对WSSV蛋白酶活性无影响。Leupeptin使蛋白酶活性降低12.29%。Chymostatin在质量浓度为12.5～25.0mg/L时,对WSSV蛋白酶活性有强烈的抑制作用,表明WSSV蛋白酶类属胰凝乳蛋白酶。蛋白质修饰剂对WSSV蛋白酶活性影响的研究结果表明,组氨酸残基为WSSV蛋白酶活性基团,而巯基为非必需基团,说明WSSV蛋白酶为非巯基依赖型的蛋白酶。     

超长钝顶螺旋藻的选育及形态和生长特性初步研究

用组织匀浆破碎和离心沉降法制备和分离出钝顶螺旋藻(Spirulina platensis)Sp-Z 的单细胞或少于5个细胞的片段,并用60Coγ射线辐照处理,半致死剂量为1.2 kGy.在2.4kGy的处理组中,筛选出4株藻丝长度、螺旋数、螺旋长分别为Sp-Z的15、10和1.8倍的超长钝顶螺旋藻突变体Sp-Z(E.L).Sp-Z的生长曲线几乎呈直线型,而Sp-Z(E.L)的生长曲线则呈较明显的"S"形.在室外培养时,Sp-Z(E.L)的产量比Sp-Z高11.7%.     

Diversity in pearl millet germplasm from Cameroon

Pearl millet [Pennisetum glaucum (L). R. Br.] (syn. P. americanum (L.) Leeke) germplasm from Cameroon was collected jointly by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and the National Cereals Research and Extension Project (NCRE)/Institute of Agronomic Research (IAR), Maroua, Cameroon. Of the 1261 samples collected, 888 are pearl millet and 12 wild relatives of Pennisetums. A total of 918 accessions of pearl millet were evaluated during rainy and postrainy seasons at ICRISAT Asia Center (IAC), Patancheru, India, and 748 at Maroua, Cameroon. Considerable variation was observed for all the characters studies. At IAC, Patancheru, time to flower varied from 56 to 146 days with a mean of 114±0.62 days during the rainy and 46 to 128 days with a mean of 67±0.28 days during the postrainy season. At Maroua, the flowering time ranged from 49 to 112 days with a mean of 81±0.34 days. Plant height ranged from 230 to 450 cm with a mean of 353±1.52 cm. Spike and grain characters were more stable compared to flowering and plant height. The expression of spike characters was comparable to evaluation in postrainy season at IAC, Patancheru. In Cameroon, farmers classify pearl millet as Yadiri and Mouri, which vary for plant canopy, spike and grain characters. Mouri matures in about 95–110 days, extensively grown in the low rainfall areas of Extreme North province. Yadiri matures in 120–140 days, generally grown in the high rainfall areas of the North, Adamaoua provinces, and on the hill slopes of Extreme North province. Millet germplasm from Cameroon is a good source for more number of productive tillers, large compact spikes, and larger ivory and cream colored grain besides its potential for forage.Submitted as ICRISAT Journal Article No. 1803.     

Characterization of chickpea chromosomes by banding techniques

Summary The karyotype of Cicer arietinum L. was characterized after the use of chromosome differential staining obtained through various techniques, such as C-banding and fluorochrome staining. It was possible to individually identify all the chromosomes of this species. Moreover the use of fluorochromes with different DNA targets allowed the distinction of at least two types of heterochromatin.The importance of chickpea heterochromatin characterization is discussed in the perspective of evolutionary and breeding studies.Abbreviations BSG Barium-Saline-Giemsa banding - CMA Chromomycin A3 - DAPI 4-6-Diamidino-2-phenylindole - H33258 Bis-benzimide derivate Hoechst 33258     

Numerical characterization of forest soils using biological and biochemical properties

Summary To find if surface soils could be grouped by their biological and biochemical properties, soil samples (0–5 cm) were collected at 4-week intervals for 56 weeks from 48 woods in and around the English Lake District, and pH, loss-on-ignition (LOI), moisture content, oxygen uptake, and cellulase and phosphatase activities were measured. Results expressed on a loss-on-ignition basis were more informative than those on an oven-dry basis. In a principal component analysis of each property over the 14 samplings, the first component values represent smoothed between-plot differences; other components identify plots which behave differently from the majority at certain times. Analysis of variance showed very highly significant differences between plots for all the properties. pH and loss-on-ignition showed the smallest, but significant, differences between samplings. On a loss-on-ignition basis, the only significant correlations between first component values, and between plot means, were phosphatase with oxygen uptake and cellulase with pH. It is concluded that no individual physiological property can be used as a measure of soil bioactivity, which supports the conclusions of other authors. None of the principal component analyses of individual or combined properties showed any evidence of the existence of distinct clusters of plots. On a loss-on-ignition basis, a priori groups based on (1) pH < 3.8, (2) pH 3.8 – 5.0 and (3) pH > 5.0, showed no significant difference in moisture content. However, oxygen uptake was significantly lower in (1) than in (2). Cellulase activity was significantly greater in (3) than in (1) and (2). Phosphatase activity was significantly lower in (1) than in (2), and there appeared to be a peak at pH 3.8 – 5.0.     

Evolution of organic matter added to soils under cultivation conditions

The development of an organic matter (OM) based on mixed sheep manure and peat, when it was incorporated into soils as fertilizer, was studied. The experiment was carried out in soils under almond tree culture, with drip irrigation and non irrigation regimes. Two doses, 10 and 4.5 kg tree^–1, were assayed. Changes in the humic acid fraction one year after incorporation into soils showed oxidation and enrichment in condensed structures, as observed by an increase of the O*:H* ratio and a decrease of the H*:C* ratio, and also by FTIR spectra. The oxidative process was more significant in the coarser textured and also in the non‐irrigated soil. The evolution of the ratios C_ext:C_ox and C_HA:C_FA throughout the culture cycle was followed by sampling and chemical analysis of different forms of organic carbon. Evolution of C_ext:C_ox showed a uniform humification state in the irrigated soil, and a significant decrease in the non‐irrigated soil, at the beginning of the experiment. Curves of C_HA:C_FA evolution showed changes attributed to mineralization or drainage of the fulvic acids fraction, giving a maximum in spring in both soils and a final increase at the end of the cycle by drainage only in the irrigated soil.     

水稻茎秆螺旋突变体ts-ta的鉴定及其遗传分析

 从6000个水稻T DNA插入突变体库中筛选到1个苗期茎秆呈螺旋生长，成株期株型松散，植株矮化，抽穗延迟的突变体ts ta。取突变体弯曲的叶鞘做石蜡切片发现，突变体弯曲的叶鞘周围表皮细胞完整，但两侧细胞的大小不同。弯曲内侧细胞小，排列紧密，外侧细胞较内侧大。T1 、T2及回交结果表明，该突变体能稳定遗传且受一对隐性单基因控制，共分离分析表明该突变性状不是由于T DNA插入引起的，因此不能通过T DNA 标签法克隆该基因。