Variability in sequence of Strawberry vein banding virus

The variability of the Strawberry vein banding virus (SVBV) isolates was investigated. In total 267 strawberry plants from 6 European countries and North America were tested for the presence of SVBV. Only 4 plants were positive. Partial genomic sequences of the capsid protein gene of three North American SVBV isolates were determined. Only minor sequence variability (0.7 %) was observed during a comparison with existing nucleotide data of the European and the North American isolates (9 isolates). No variability at all could be found in the annealing regions of primers and probes used for molecular detection of SVBV for these isolates. However, a comparison to a sequence of a Chinese isolate published recently revealed a much higher DNA sequence difference (9.5 %) of this isolate.     

基因枪法转化基因在小麦条锈菌中的瞬时表达

以小麦条锈菌(Puccinia striiformis f.sp.tritici)野生毒性菌株为转化受体,以含有gus报告基因的质粒(pGUS6L20)和潮霉素抗性基因的质粒(pKLHyg14)为载体,应用基因枪法研究了小麦条锈菌夏孢子遗传转化的瞬时表达特征。结果表明,在金粉直径为0.6μm、射程6cm、载体DNA5μL、可裂膜压力为900Psi或1100Psi时,gus基因和潮霉素抗性基因的瞬时表达率相对较高。     

链霉菌Strz-6木聚糖酶的纯化和固定化研究

链霉菌胞外木聚糖酶经过盐析、离子交换和分子筛层析纯化,粗酶液被纯化了32.5倍,比活力达498u/mg,活力回收46.6%。纯化后的酶固定在戊二醛交联的壳聚糖上,酶活回收率为42.8%。固定化酶的最适pH为6.0,最适温度为60℃,且固定化酶在65~75℃活力都较高。该酶的耐热性比较强,固定化酶热稳定性优于原酶;以木聚糖为底物,固定化酶的表观米氏常数为0.93×10-2g/L。     

Ciborinia gentianae sp. nov., the causal organism of sclerotial flower blight of cut-flower gentians

A new Ciborinia causing sclerotial flower blight of cut-flower gentians (Gentiana triflora var. japonica and interspecific hybrids between related species or varieties) is described as Ciborinia gentianae on the morphological basis of sclerotia and apothecia. The characteristics of Ciborinia gentianae are (1) an abundant production of spermodochia in the hollow cavity of host stems; (2) flat and thin sclerotia produced beneath the epidermis and the inclusion of host vascular remnants within their medulla; (3) globose cells composed of ectal excipulum of apothecia; (4) elongated cells with a slight apical swelling in ectal excipulum at the apothecial margin; and (5) tetra nucleate ascospores. Asci and ascospores mounted in Melzer's reagent measured 156–208 × 8–12 μm and 11.8–15 × 5.5–7.1 μm, respectively.     

Trichosporon siamense sp. nov. isolated from insect frass in Thailand

A strain of yeast isolated from insect frass collected in Thailand was found to represent a hitherto undescribed species of a basidiomycetous anamorphic genus Trichosporon. It is described as Trichosporon siamense. In the phylogenetic tree based on the D1/D2 region sequences of 26S rDNA, this yeast constitutes a cluster with several Q-9 having species of Trichosporon including T. otae and T. brassicae but is clearly differentiated from these species by 1.8% or more base substitutions. In the internal transcribed spacer region (ITS1 and ITS2), this species differs from T. scarabaeorum, the nearest species, by 6.5% base substitution.     

Himantura lobistoma, a new whipray (Rajiformes: Dasyatidae) from Borneo, with comments on the status of Dasyatis microphthalmus

A new long-snouted whipray, Himantura lobistoma, is described on the basis of seven specimens collected from the southeastern sector of the South China Sea, off western Borneo. It belongs to a subgroup of Himantura species provisionally defined herein as the “uarnacoides” complex that includes five nominal species: H. chaophraya, H. granulata, H. hortlei, H. pastinacoides, and H. uarnacoides. These whiprays all have a similar lateral disc shape (i.e., pectoral-fin apices broadly rounded rather than narrowly rounded or angular), a plain colouration (i.e., usually uniform light to dark brown dorsally, and pale or whitish ventrally with or without a dark margin), a long and slender whiplike tail, and platelike denticles in a broad dorsal band in adults. Himantura lobistoma can be distinguished from the superficially similar H. hortlei by its highly protrusible mouth and pelvic girdle with prominent lateral prepelvic processes. It differs from other members of the “uarnacoides” complex by a combination of internal and external morphological characteristics (e.g., having an extremely elongate snout and very small eyes). Another long-snouted stingray from the region, Dasyatis microphthalmus Chen, inadequately described and known only from the lost holotype, is considered a nomen dubium. It had been assigned to Himantura based on the absence of an obvious ventral cutaneous tailfold but may be conspecific with D. acutirostra.     

Spawning site of the fluvial eight-barbel loach, Lefua sp., in the natural environment

The spawning site of the fluvial eight-barbel loach, Lefua sp. (sensu Hosoya, 1993; Japanese name: nagare-hotoke-dojo), an endangered species, was investigated by searching for fertilized eggs in June and July 1995–1997 in an upper reach of the Kako River, Hyogo Prefecture, Japan. We obtained one egg each by a random sampling with agitating the river bottom (80 trials) and by collecting drift samples (89 trials). This finding indicates that the eggs were not scattered on the bottom or into the water column after being spawned. Two individual males were observed to patrol around particular interstices occurring under the buried cobbles and under the boulders that formed the riverbank. Males pecked other individuals that approached around the interstices. We obtained 9 and 15 eggs, respectively, from two such interstices in only two collection trials. The interstices were suggested to function as the spawning sites of this endangered fish in nature.     

The spatio-temporal distribution dynamics of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Coleoptera: Curculionidae), and its larval parasitoids in canola in western Canada

Distribution patterns of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), and its larval parasitoids were investigated in commercial fields of spring canola (Brassica rapa L. and Brassica napus L.) in southern Alberta, Canada, from 2002 to 2004 in relation to developmental stages of its host plants. Adult weevils invaded fields along one or more fronts when crops were in bud to early flower. Significant clustering of adults along field edges in early stages of invasion was followed by more homogeneous distributions as canola reached the mid to late flowering and pod enlargement stages. Larval weevil distributions, as indicated by exit holes in siliques at the end of the season, were often aligned spatially with adult distributions, but they did not coincide in all regions of the fields. The primary ectoparasitoid species attacking weevil larvae comprised Necremnus tidius (Walker) (Hymenoptera: Eulophidae), and Trichomalus lucidus (Walker), Chlorocytus sp., and Pteromalus sp. (Hymenoptera: Pteromalidae). Parasitism rates increased from 0.1 to 5.0% over the three years of study. Parasitoid distributions were often, but not consistently, spatially associated with high densities of C. obstrictus larvae. Lack of close spatial alignment of parasitoids and their hosts probably reflects low parasitoid numbers in comparison with an abundant resource of weevil larvae, and a lack of co-evolutionary history between host and parasitoids. Some parasitoids invaded fields early in host plant development, at the same time that weevils invaded. Unfortunately the synchronous invasions of host and parasitoids indicate that insecticidal applications to reduce adult weevil infestations may be detrimental to these beneficial species.     

几种杀虫剂对南美斑潜蝇及其寄生蜂潜蝇茧蜂的毒力

测定了阿维菌素、灭蝇胺、杀虫单、毒死蜱、灭多威、顺式氯氰菊酯6种杀虫剂对南美斑潜蝇2龄幼虫、成虫及其寄生蜂潜蝇茧蜂的室内毒力,并考察了灭蝇胺、阿维菌素和杀虫单对南美斑潜蝇的田间防效。在所研究浓度下,阿维菌素、灭蝇胺对2龄幼虫的毒力较高,但对南美斑潜蝇成虫和潜蝇茧蜂的毒力较低;杀虫单对南美斑潜蝇成虫、2龄幼虫和潜蝇茧蜂的毒力均较高;毒死蜱、灭多威、顺式氯氰菊酯对南美斑潜蝇2龄幼虫的毒力较低,而对潜蝇茧蜂的毒力较高。田间条件下,灭蝇胺、阿维菌素和杀虫单都对田间南美斑潜蝇具有较高防效。     

产碱性纤维素酶嗜碱芽孢杆菌AH-8的研究

从贵州、云南、海南、安徽、四川、辽宁等地采集碱性土样,分离筛选到1株能稳定的产生碱性纤维素酶的嗜碱性芽孢杆菌AH-8。研究表明,该菌株最适产酶温度为37℃,最适发酵时间为36 h;采用均匀设计法对其发酵培养基进行优化,优化培养基配方(%):淀粉3.0,胰蛋白胨1.5,牛肉膏1.5,葡萄糖0.3,KH2PO40.1,初始pH 10.0。在优化培养基条件下,其产酶量提高了120%。碱性纤维素酶最适反应温度为60℃;最适反应pH 10.0;0.01%Co2 对酶活力有一定激活作用。