Toxicity of <Emphasis Type="Italic">Bacillus sphaericus</Emphasis> LP1-G Against Susceptible and Resistant <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> and the Cloning of the Mosquitocidal Toxin Gene

Bacillus sphaericus LP1-G, belonging to flagellar serotype H3, has been found to have moderate toxicity against two resistant Culex quinquefasciatus colonies (RLCq1 and RLCq2) and the susceptible contrast (SLCq). With an aim of screening mosquitocidal acting factor, a partial genome library was prepared from a partial HindIII digest of the total DNA from Bacillus sphaericus LP1-G. Two thousand twenty Escherichia coli clones were screened for toxicity against susceptible SLCq, and a toxic clone, designated E-UL68, was chosen for further study. The recombinant E-UL68 performed toxicity against both susceptible and two resistant colonies, having the same level of toxicity as that of wide-type strain LP1-G. Sequence analysis revealed that the inserted fragment was composed of 3876 nucleotides and contained a complete gene, whose sequence was identical to that of the mtx gene from B. sphaericus SSII-1. Because the binary toxin produced during sporulation of strain LP1-G has no activity against the target mosquitoes, this indicates that the Mtx toxin or other active factors might perhaps be responsible for the toxicity of LP1-G against different colonies of mosquito larvae.Received: 7 October 2002 / Accepted: 4 November 2002     

Effects of Maternal Zinc Glycine on Mortality,Zinc Concentration,and Antioxidant Status in a Developing Embryo and 1-Day-Old Chick

This study was conducted to investigate the effects of maternal zinc glycine (Zn-Gly) supplementation as an alternative for zinc sulfate (ZnSO₄) on mortality, zinc (Zn) concentration, and antioxidant status in a developing embryo and 1-day-old chick. Six hundred 39-week-old broiler breeders were randomly assigned to 6 treatments, each treatment including 5 replicates with 20 birds each. Six treatments received a basal diet (control, 24 mg Zn/kg diet) or a basal diet supplemented with ZnSO₄ (80 mg Zn/kg) or Zn-Gly (20, 40, 60, or 80 mg Zn/kg), respectively. The experiment lasted for 8 weeks after a 4-week pre-experiment with a basal diet. At the last week, 100 eggs per replicate were randomly collected for incubation. Compared with the control treatment, Zn supplementation decreased (P < 0.05) embryo mortalities of the late stage and the whole period, increased (P < 0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick, and improved (P < 0.05) antioxidant status in the embryo of d19 and 1-day-old chick. Compared with the ZnSO₄ treatment, 80 mg Zn/kg Zn-Gly treatment significantly decreased (P < 0.05) the late stage embryo mortality and increased (P < 0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick. The 80 mg Zn/kg Zn-Gly treatment significantly increased (P < 0.05) copper-zinc superoxide dismutase activity in d19 embryo and 1-day-old chick, total superoxide dismutase activity in 1-day-old chick, and copper-zinc superoxide dismutase messenger RNA (mRNA) abundance of d9 embryo and 1-day-old chick than that in ZnSO₄ treatment. The liver metallothionein concentration of the developing embryo and 1-day-old chick and its mRNA abundance of d19 embryo were also significantly increased (P < 0.05) in the 80 mg Zn/kg Zn-Gly treatment in comparison with ZnSO₄ treatment. In conclusion, maternal Zn supplementation decreased embryo mortalities of the late stage and the whole period by increasing liver Zn concentration and antioxidant status in d19 embryo and 1-day-old chick, and 80 mg Zn/kg from Zn-Gly treatment was the optimum choice.     

Effect of ecological engineering on the nutrient content of surface sediments in Lake Taihu, China

Ecological engineering was carried out in Meiliang Bay of Lake Taihu beginning in 2003 in order to improve water quality. There were two main objectives: to improve the growth environment for macrophytes, and to restore macrophyte assemblages. We examined surface sediments once per month beginning in April 2005 to study the response of sediment nutrient content to the ecological engineering. Average total nitrogen (TN) and total phosphorus (TP) concentrations in the surface sediments were 7043 and 1370 mg kg⁻¹, respectively, in May 2005, while after 1 year, TN concentration was reduced to 2929 mg kg⁻¹ and TP concentration was reduced to 352 mg kg⁻¹. We conclude that ecological engineering can lower the nutrient content in surface sediments when it is used to improve water quality.     

Complete chloroplast genome sequence of a tree fern Alsophila spinulosa : insights into evolutionary changes in fern chloroplast genomes

Background  

Ferns have generally been neglected in studies of chloroplast genomics. Before this study, only one polypod and two basal ferns had their complete chloroplast (cp) genome reported. Tree ferns represent an ancient fern lineage that first occurred in the Late Triassic. In recent phylogenetic analyses, tree ferns were shown to be the sister group of polypods, the most diverse group of living ferns. Availability of cp genome sequence from a tree fern will facilitate interpretation of the evolutionary changes of fern cp genomes. Here we have sequenced the complete cp genome of a scaly tree fern Alsophila spinulosa (Cyatheaceae).     

中国北鳅谱系地理学分析

北鳅(Lefua costata)为冷水性鱼类,分布于淮河以北,分析遗传结构能够反映其适应环境变迁的响应.基于线粒体D-loop区211条序列分析了我国北鳅的谱系地理学和遗传多样性,样本采自9条水系共18个样点.单倍型分析显示共计55个单倍型,呈高单倍型多样性(h=0.9304)和高核苷酸多样性(π=0.0087).单...     

苏云金杆菌vip3A基因的克隆、表达及杀虫活性分析

用全长PCR方法从野生型苏云金杆菌（Bacillus thuringiensis ,Bt)菌株S184中克隆了2.3kb大 vip3A基因并进行了序列分析。将vip3A-S184基因插入表达载体pQE30构建了表达质粒pOTP,转化大肠杆菌M15,转化子经1mmol/L IPTG诱导后可表达89kD大小的Vip3A-S184蛋白,并得到Western blot证实。蛋白可溶性试验表明,目的蛋白中约有19％是可溶的,用透射电镜观察到大多数蛋白是以包涵体形式存在的。因此,可以在自然条件下进行目的蛋白的纯化和对家兔进行免疫制备多克隆抗体,用于苏云金杆菌Vip3A蛋白表达的检测。利用IPTG进行诱导培养的菌液对甜菜夜蛾（Spodoptera exigua）,斜纹夜蛾（S.litura)和棉铃虫（Helicoverpa armigera)等3种害虫的初孵幼虫进行生物测定,结果表明,Vip3A-S184蛋白对夜蛾科害虫具有较高的杀虫活性。     

Wallemia sebi的RNase活性和抗植物病原真菌活性的初步研究

Wallemia是中国的一新记录属,该属只有Wallemiasebi一个种。Wallemiasebi在PDA平板上对植物病原真菌尖孢镰刀菌(Fusariumoxysporum)和大丽花轮枝孢(Verticilliumdahliae)有强抑制作用。YG培养基上培养的Wallemiasebi菌丝体有RNase活性,在0·1mol/LpH7·5的磷酸缓冲液中其活性最高,达322·0U/mg。     

<Emphasis Type="Italic">Arthrobacter halodurans</Emphasis> sp. nov., a new halotolerant bacterium isolated from sea water

A novel Gram-positive, halotolerant, non-sporulating, non-motile, catalase-positive, oxidase-negative and aerobic bacterium, designated strain JSM 078085^T, was isolated from sea water collected from the South China Sea. Strain JSM 078085^T exhibited a rod-coccus growth cycle and produced a yellow pigment. The strain was able to grow in the presence of 0–12% (w/v) NaCl and at pH 6.0–9.5 and 4–35°C; optimum growth was observed at pH 7.0 and 25–30°C in the absence of NaCl. The peptidoglycan type was A4α (l-Lys–l-Ala–l-Glu). Cell-wall sugars contained galactose and glucose. Strain JSM 078085^T contained menaquinone MK-9(H₂) as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major polar lipids. The major cellular fatty acids were anteiso-C_15:0, iso-C_15:0 and anteiso-C_17:0 and the DNA G + C content was 63.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain JSM 078085^T should be assigned to the genus Arthrobacter, being most closely related to the type strain of Arthrobacter rhombi (sequence similarity 97.1%), and the two strains formed a distinct lineage in the phylogenetic tree. The level of DNA–DNA relatedness between strain JSM 078085^T and the type strain of Arthrobacter rhombi was 10.6%. The combination of phylogenetic analysis, DNA–DNA relatedness, phenotypic characteristics and chemotaxonomic data supported the view that strain JSM 078085^T represents a novel species of the genus Arthrobacter, for which the name Arthrobacter halodurans sp. nov. is proposed. The type strain is JSM 078085^T (=DSM 21081^T=KCTC 19430^T). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain JSM 078085^T is EU583729.