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51.
Nucleotide sequence of the gene coding for a 130-kDa mosquitocidal protein of Bacillus thuringiensis israelensis 总被引:4,自引:0,他引:4
T Yamamoto I A Watkinson L Kim M V Sage R Stratton N Akande Y Li D P Ma B A Roe 《Gene》1988,66(1):107-120
The nucleotide sequence of pVB131 containing the gene coding for a 130-kDa Bacillus thuringiensis israelensis (B.t.isr) mosquitocidal protein was determined. The pVB131 plasmid was constructed by Sekar and Carlton [Gene 33 (1985) 151-158]. Our sequencing revealed only one open reading frame large enough to code for a protein of 130 kDa. The translation start site was determined by sequencing the protein isolated from B.t.isr. The amino acid sequence of the protein was deduced from the nucleotide sequence, and its Mr was determined as 128,505. Immunological and biochemical analyses of B.t.isr mosquitocidal proteins indicated that the 130-kDa protein coded by pVB131 was indeed expressed in B.t.isr. Comparing the peptide sequence of the 130-kDa B.t.isr toxin with the sequences of other B.t. toxins having activities specific to lepidopteran species showed that several domains were highly homologous. This suggests that they are evolutionarily related to each other, and in the evolutionary process the sequences in the homologous domains that are important to the insecticidal activity have been conserved. 相似文献
52.
Ma I. G. Siso M. A. Murado J. M. Franco J. Miron Ma.P. González 《Biotechnology letters》1988,10(6):431-436
Summary Some possible criteria in selection of amylolytic microorganisms for their mixed culture with non-amylolytic yeasts are discussed, and the growth of several microfungus-yeast mixed cultures on mussel processing wastes are studied. 相似文献
53.
震旦鸦雀种群生态的研究 总被引:4,自引:0,他引:4
震旦鸦雀是一种小型濒危鸟类,在IUCN和ICBP出版的红皮书中,共同认定为Ⅰ(Indeterminate)级。本文是作者于1985~1986年期间,对种群生态进行研究的首次报道。该鸟栖息于上海沿海芦苇滩中。种群密度1.21±0.57对/公顷。文中还论述数量变动和种群活动的变化规律。在奉贤沿海估计有290~387对。在越冬期中,剥取芦鞘内的寄生虫等为食。由于围垦不断发展,栖息地日益缩小,因此在生存上受到严重威胁。 相似文献
54.
55.
Effect of postnatal development on calcium currents and slow charge movement in mammalian skeletal muscle 总被引:16,自引:3,他引:13 下载免费PDF全文
Single- (whole-cell patch) and two-electrode voltage-clamp techniques were used to measure transient (Ifast) and sustained (Islow) calcium currents, linear capacitance, and slow, voltage-dependent charge movements in freshly dissociated fibers of the flexor digitorum brevis (FDB) muscle of rats of various postnatal ages. Peak Ifast was largest in FDB fibers of neonatal (1-5 d) rats, having a magnitude in 10 mM external Ca of 1.4 +/- 0.9 pA/pF (mean +/- SD; current normalized by linear fiber capacitance). Peak Ifast was smaller in FDB fibers of older animals, and by approximately 3 wk postnatal, it was so small as to be unmeasurable. By contrast, the magnitudes of Islow and charge movement increased substantially during postnatal development. Peak Islow was 3.6 +/- 2.5 pA/pF in FDB fibers of 1-5-d rats and increased to 16.4 +/- 6.5 pA/pF in 45-50-d-old rats; for these same two age groups, Qmax, the total mobile charge measurable as charge movement, was 6.0 +/- 1.7 and 23.8 +/- 4.0 nC/microF, respectively. As both Islow and charge movement are thought to arise in the transverse-tubular system, linear capacitance normalized by the area of fiber surface was determined as an indirect measure of the membrane area of the t-system relative to that of the fiber surface. This parameter increased from 1.5 +/- 0.2 microF/cm2 in 2-d fibers to 2.9 +/- 0.4 microF/cm2 in 44-d fibers. The increases in peak Islow, Qmax, and normalized linear capacitance all had similar time courses. Although the function of Islow is unknown, the substantial postnatal increase in its magnitude suggests that it plays an important role in the physiology of skeletal muscle. 相似文献
56.
小麂、黑麂、赤麂精母细胞联会复合体的比较研究 总被引:7,自引:1,他引:6
本工作以界面铺张——硝酸银染色技术,对小麂(Muntiacus reeuesi)、黑麂(M.crinifrons)和赤麂(M.muntjak)的精母细胞联会复合体(Syna ptonemal complex,SC)进行亚显微结构的比较研究。结果表明: 1.SC的平均相对长度和臂比指数同有丝分裂细胞相应染色体的数值有很好的一致性。根据SC的相对长度和臂比指数绘制了三种麂的SC组型图。雄性黑麂减数分裂前期形成一个复杂的易位多价体,意味着其核型的演化过程涉及两次染色体易位和一次臂间倒位。 2.在减数分裂前期,性染色体的形态和行为同常染色体的有明显差异,如性染色体嗜银性较强,配对延迟等。XY的配对起始于早粗线期,在中粗线期,Y的全长均同X配对;XY-SC开始解体于晚粗线期。 3.在粗线期,X染色体未配对区域出现自身折叠,形成“发夹”状结构。这种“发夹”结构的形成,可能是在性染色体的进化过程中,X染色体通过不对称易位得到的重复片段在减数分裂前期同源配对的一种细胞学表现。 相似文献
57.
单克隆抗体对肾综合征出血热病毒50k蛋白的分析 总被引:1,自引:0,他引:1
用18株抗肾综合征出血热(Hemorrhagic fever with renal syndrome,以下简称HFRS)病毒McAb,以Western-blot技术分析了纯化的该病毒50k蛋白。结果有7株McAb可与该蛋白反应。这7株McAb的特性(包括感染细胞膜抗原免疫荧光染色模式、中和活性及HI活性等)亦各不相同,提示它们所针对的抗原决定簇的特性也不同。用ELISA阻断试验等证明,上述7株McAb中,有5株所针对的抗原决定簇之间有部分相同或重叠,提示这些具有不同特性的抗原决定簇确实位于同一结构蛋白上。分析结果表明,该50k蛋白的特性及结构均较复杂,尚须进一步研究。 相似文献
58.
白腹锦鸡,红腹锦鸡,中国雉鸡SC组型的比较研究 总被引:1,自引:0,他引:1
以微铺展—硝酸银染色技术制备三种鸡的SC标本,进行电镜观察。结果表明:三种鸡的SC组非常相似,即2n=82,ZZ/ZW型性别决定,雄性为ZZ。除1号SC和Z-SC为中着丝粒外,其余均为端着丝粒。Z-SC的相对长度有明显的细胞间差异;平均相对长度度介于第3和第4号SC之间。三者SC组型上的差异主要表现在相应SC长度上的不同。并对其亲缘关系及在鸟类进化中的可能地位进行了讨论。此外,在微铺展法制备的锦鸡精母细胞SC标本中还发现了巨大中心粒,这在高等动物尚属首次。 相似文献
59.
Woronin bodies are present near all septal pores and in conidia of Arthrinium strains and may regulate cytoplasmic flow in both injured and actively growing healthy colonies. They vary in size and frequency, the central one plugs the septal pores in actively developing colonies and in mature conidia. The septa are thinner in the Woronin-body region. 相似文献
60.
Y Ma B I Wilson S Bijvoet H E Henderson E Cramb G Roederer M R Ven Murthy P Julien H D Bakker J J Kastelein 《Genomics》1992,13(3):649-653
We have previously reported two common lipoprotein lipase (LPL) gene mutations underlying LPL deficiency in the majority of 37 French Canadians (Monsalve et al., 1990. J. Clin. Invest. 86: 728-734; Ma et al., 1991. N. Engl. J. Med. 324: 1761-1766). By examining the 10 coding exons of the LPL gene in another French Canadian patient, we have identified a third missense mutation that is found in two of the three remaining patients for whom mutations are undefined. This is a G to A transition in exon 6 that results in a substitution of asparagine for aspartic acid at residue 250. Using in vitro site-directed mutagenesis, we have confirmed that this mutation causes a catalytically defective LPL protein. In addition, the Asp250----Asn mutation was also found on the same haplotype in an LPL-deficient patient of Dutch ancestry, suggesting a common origin. This mutation alters a TaqI restriction site in exon 6 and will allow for rapid screening in patients with LPL deficiency. 相似文献