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991.
分离了苏芸金杆菌库斯塔克变种MS07A(Bacillus thuringiensis var.kurstaki MS07A)的质粒,经HindⅢ酶解、凝胶电泳和Southern转移后,用DIGdUTP标记的质粒pES1的EcoR Ⅰ—F片段作探针进行DNA分子杂交,发现5.3、6.6和7kb左右的DNA片段含Cry Ⅰ基因。用Glass milk合并回收这些片段,克隆到pUC18的HindⅢ位点上并转化大肠杆菌JM109。通过菌落原位杂交、重组质粒的限制性消解等分析方法,选出带有Cry Ⅰ基因并能在大肠杆菌中表达其毒蛋白的转化子。初步生物测定结果表明。转化子TM48和TM76对松毛虫和菜青虫有毒杀活性。 相似文献
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994.
Regional lymph node lymphocytes from five patients with primary lung cancer were analyzed for subset composition, and exposed
in vitro to the polyclonal human B cell mitogen Staphylococcus aureus Cowan I (SACI) or the murine B cell mitogen lipopolysaccharide
(LPS) and then fused with mouse myeloma cells for investigation at the clonal level of their antibody (Ab) production and
its statistical relation to the original subset composition. No correlation was found between the proportion of CD19+, CD23+,
or CD3+ cells in the lymphocyte sample prior to its exposure to either SACI or LPS, and the Ab production efficiency, defined
as the ratio of the number of Ab producing wells to the total number of proliferating wells. For lymphocytes exposed to LPS,
however, a strong correlation (r = 0.931, p = 0.02) was observed between the Ab production efficiency and the ratio of CD8+
to CD3+ cells (CD8/CD3) in the original sample at least within the ranges studied (CD8/CD3 = 0.216–0.288). For those exposed
to SACI, no correlation was found between the Ab production efficiency and the CD8/CD3 ratio (r = 0.881, p = 0.12) or the
proportion of CD8+ cells (r = 0.808, p = 0.19) in the original sample. These results suggest that the repertoire of B cells
responsive to LPS is different at least in part from the repertoire responsive to SACI and that the ratio CD8/CD3 could serve
as a practical predictor for Ab production by human lymphocytes stimulated with LPS.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
995.
The reaction of 2-(methylthioethanol) with 1,8-dichloroanthraquinone and 1,5-dichloroanthraquinone in THF with base produces 1,8-bis(2-methylthioethoxy)anthraquinone (1) and 1,5-bis(2-methylthioethoxy)anthraquinone (2), respectively. Silver(I) complexes of 1 and 2 have been synthesized after combination with [Ag(CH3CN)4]BF4 in 1:1 M ratio to yield, [(1,8-bis(2-methylthioethoxy)anthraquinone)Ag]BF4, (3) and [(1,5-bis(2-methylthioethoxy)anthraquinone)Ag·CH3CN]BF4, (4). X-ray crystal structures of the free ligand (1) and the Ag(I) complexes (3 and 4) are reported. The intraannular carbonyl group forms a coordinate-covalent bond with Ag(I) and, in the solid state, both silver(I) complexes are found as coordination polymers. 相似文献
996.
Larvae of the insect Galleria mellonella were employed to assess the in vivo antifungal efficacy of ([Ag2(mal)(phen)3]), AgNO3 and 1,10-phenanthroline. Larvae pre-inoculated with these compounds were protected from a subsequent lethal infection by
the yeast Candida albicans while larvae inoculated 1 and 4 h post-infection showed significantly increased survival (P < 0.01) compared to control larvae. Administration of these compounds resulted in an increase over 48 h in the density of
insect haemocytes (immune cells) but there was no widespread activation of genes for antimicrobial peptides. This work demonstrates
that G. mellonella larvae may be employed to ascertain the antifungal efficacy of silver(I) compounds and offers a rapid and effective means
of assessing the in vivo activity of inorganic antimicrobial compounds. 相似文献
997.
Distinct chemical species of iron were investigated by Mössbauer spectroscopy during iron uptake into cucumber roots grown in unbuffered nutrient solution with or without 57Fe-citrate. Mössbauer spectra of iron deficient roots supplied with 10–500 μM 57Fe-citrate for 30–180 min and 24 h and iron-sufficient ones, were recorded. The roots were analysed for Fe concentration and Fe reductase activity. The Mössbauer parameters in the case of iron-sufficient roots revealed high-spin iron(III) components suggesting the presence of FeIII-carboxylate complexes, hydrous ferric oxides and sulfate–hydroxide containing species. No FeII was detected in these roots. However, iron-deficient roots supplied with 0.5 mM 57FeIII-citrate for 30 min contained significant amount of FeII in a hexaaqua complex form. This is a direct evidence for the Strategy I iron uptake mechanism. Correlation was found between the decrease in Fe reductase activity and the ratio of FeII–FeIII components as the time of iron supply was increased. The data may refer to a higher iron reduction rate as compared to its uptake/reoxidation in the cytoplasm in accordance with the increased reduction rate in iron deficient Strategy I plants. 相似文献
998.
Recently [Marquardt et al. (2000) Gene 255: 257–265], we isolated a gene encoding a polypeptide of the light-harvesting complex
of Photosystem I (LHC I) of the red alga Galdieria sulphuraria. By screening a G. sulphuraria cDNA library with a DNA probe coding for the conserved first transmembrane helix of this protein we isolated four additional
genes coding for LHC I polypeptides. The deduced preproteins had calculated molecular masses of 24.6–25.6 kDa and isoelectric
points of 8.09–9.82. N-terminal sequencing of a LHC I polypeptide isolated by gel electrophoresis allowed us to determine
the cleavage site of the transit peptide of one of the deduced polypeptides. The mature protein has a calculated molecular
mass of 20.6 kDa and an isoelectric point of 7.76. The genes were amplified from nuclear G. sulphuraria DNA by polymerase chain reaction (PCR) using oligonucleotides annealing in the regions of the start and stop codons as primers.
All genomic sequences were 80–300 base pairs longer than the PCR products obtained from the respective cDNA clones, pointing
to the existence of 1–5 introns per gene. The G. sulphuraria genes form a homogeneous gene family with overall pairwise amino acid identities of 46.0–56.6%. Homology to two diatom, one
cryptophytic and two higher plant light-harvesting polypeptides was lower with pairwise identities of 21.1–34.1%. Only one
diatom polypeptide showed a higher degree of identity of up to −39.3%.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
999.
ES细胞嵌合能力的强弱是人们利用ES细胞获得转基因小鼠时十分关心的问题。本文通过囊胚显微注射法将15个左右ES细胞注入C57 BL/6 J品系小鼠3.5天囊胚的囊胚腔中观察嵌合鼠毛色嵌合情况,统计嵌合鼠的出生率;以及用葡萄糖磷酸异构酶(GPI)电泳法检测ES细胞在嵌含鼠体内各种组织和器官的嵌合情况,对于HPRT缺陷(HDC)细胞和MES-PU-13细胞的嵌合能力我们作了较详细的研究,结果表明MESPU-13细胞嵌合能力较强,而HDC细胞嵌合能力较弱,并讨论分析了这种结果的原因。 相似文献
1000.
Maria Luz Perez José Ramón Valverde Beatriz Batuecas Francisco Amat Roberto Marco Rafael Garesse 《Journal of molecular evolution》1994,38(2):156-168
From the cloned mitochondrial DNAs (mtDNAs) isolated from two bisexual species, one Mediterranean, Artemia salina, and one American, Artemia franciscana, and two parthenogenetic (diploid and tetraploid) strains of Artemia parthenogenetica collected in Spain, physical maps have been constructed and compared. They are extremely different among themselves, much more than the differences between Drosophila melanogaster and D. yakuba and in the same range of different mammalian species such as mouse/rat or man/cow. The nucleotide sequences of two regions of mtDNA encoding parts of the cytochrome c oxidase subunit I (COI) and cytochrome b (Cytb) genes have been determined in the two bisexual species and the two parthenogenetic strains. Comparisons of these sequences have revealed a high degree of divergence at the nucleotide level, averaging more than 15%, in agreement with the differences found in the physical maps. The majority of the nucleotide changes are silent and there is a strong bias toward transitions, with the CT substitutions being highly predominant. The evolutionary distance between the two Artemia parthenogenetica is high and there is no clear relationship with any of the bisexual species, including the one present nowadays in Spain. Using a combination of molecular (mtDNA) and morphological markers it is possible to conclude that all of these Artemia isolates should be actually considered as belonging to different species, even the two Artemia parthenogenetica diploidica and tetraploidica.On sabbatical leave from Departamento de Bioquímica, Facultad de Veterinaria, Universidad Complutense de Madridearly Italian artemiologists to designate the Medi-Beatriz Batuecas died in an accident during the Christmas holy days of 1988 after she had initiated this workCorrespondence to: R. Garesse 相似文献