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41.
Genetic exchange in soil between introduced chlorobenzoate degraders and indigenous biphenyl degraders. 总被引:2,自引:0,他引:2 下载免费PDF全文
Pseudomonas aeruginosa JB2, a chlorobenzoate degrader, was inoculated into soil having indigenous biphenyl degraders but no identifiable 2-chlorobenzoate (2CBa) or 2,5-dichlorobenzoate (2,5DCBa) degraders. The absence of any indigenous chlorobenzoate degraders was noted by the failure to obtain enrichment cultures with the addition of 2CBa, 3CBa, or 2,5DCBa and by the failure of soil DNA to hybridize to the tfdC gene, which encodes ortho fission of chlorocatechols. In contrast, DNA extracted from inoculated soils hybridized to this probe. Bacteria able to utilize both biphenyl and 2CBa as growth substrates were absent in uninoculated soil, but their presence increased with time in the inoculated soils. This increase was related kinetically to the growth of biphenyl degraders. Pseudomonas sp. strain AW, a dominant biphenyl degrader, was selected as a possible parental strain. Eight of nine recombinant strains, chosen at random, had high phenotypic similarity (90% or more) to the inoculant; the other, strain JB2-M, had 78% similarity. Two hybrid strains, P. aeruginosa JB2-3 and Pseudomonas sp. JB2-M, were the most effective of all strains, including strain AW, in metabolizing polychlorinated biphenyls (Aroclor 1242). Repetitive extragenic palindromic-PCR analysis of putative parental strains JB2 and AW and the two recombinant strains JB2-3 and JB2-M showed similar fragments among the recombinants and JB2 but not AW. These results indicate that the bph genes were transferred to the chlorobenzoate-degrading inoculant from indigenous biphenyl degraders. 相似文献
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APC基因是1991年被发现的一类肿瘤抑制基因,它被定位于人第5号染色体5q21处。APC基因如发生缺失或突变,则易患直肠肿瘤,并伴有部分先天痴呆的病例。本工作在孟帆已获得的APC基因在豚鼠中的同源cDNA的基础上,完成了对它的亚克隆,并利用原位杂交和RNA酶保护分析的方法,对它在脑中的分布进行了研究。发现APCmRNA主要在海马、大脑和小脑中表达;嗅球中杂交信号稍弱,脑干中最弱。海马中阳性细胞主要是锥体细胞,小脑中则主要是内层颗粒细胞。在一个月大的豚鼠胚胎的脑中也观察到相似的表达型式。进一步的研究有助于我们更好地了解神经发育和先天痴呆发生的分子机制。 相似文献
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Summary Two strains of osmophilic yeast which were isolated from honey-comb, produced good yields of erythritol as a main product. These strains were identified as Trichosporonoides sp., 150-5 and 331-1.From the fermentation studies with these strains using glucose and sucrose as substrate, strain 331-1 produced more erythritol as the sole polyhydric product,with trace quantities of glycerol, than strain 150-5. 相似文献
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通过对N、P、K不同施肥条件下的“秦油2号”油菜植株内含物等与萝卜蚜有翅率关系的研究,建立了8个数学模型,结果表明可溶性糖、总N、糖与蛋白质之比和丝氨酸与萝卜蚜有翅率有密切关系,其次是天门冬氨酸、苏氨酸、谷氨酸、甘氨酸、丙氨酸、蛋氨酸、异亮氨酸、亮氨酸、酪氨酸、含水量、水溶性蛋白、酰胺氮和含P量等. 相似文献
50.
Wei Dai Yong gang Dai Dong feng Ren Da wei Zhu 《Journal of biochemical and molecular toxicology》2023,37(5):e23313
This study investigated that dieckol (DKL), a natural drug, inhibits colon cancer cell proliferation and migration by inhibiting phosphoinositide-3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR) phosphorylation in HCT-116 cells. The cells were treated with DKL in various concentrations (32 and 50 μM) for 24 h and then analyzed for various experiments. MTT (tetrazolium bromide) and crystal violet assay investigated DKL-mediated cytotoxicity. Dichlorodihydrofluorescein diacetate staining was used to assess the reactive oxygen species (ROS) measurement, and apoptotic changes were studied by dual acridine orange and ethidium bromide staining. Protein expression of cell survival, cell cycle, proliferation, and apoptosis protein was evaluated by western blot analysis. Results indicated that DKL produces significant cytotoxicity in HCT-116, and the half-maximal inhibitory concentration was found to be 32 μM for 24-h incubation. Moreover, effective production of ROS and enhanced apoptotic signs were observed upon DKL treatment in HCT-116. DKL induces the expression of phosphorylated PI3K, AKT, and mToR-associated enhanced expression of cyclin-D1, proliferating cell nuclear antigen, cyclin-dependent kinase (CDK)-4, CDK-6, and Bcl-2 in HCT-116. In addition, proapoptotic proteins such as Bax, caspase-9, and caspase-3 were significantly enhanced by DKL treatment in HCT-116. Hence, DKL has been considered a chemotherapeutic drug by impeding the expression of PI3K-, AKT-, and mTOR-mediated inhibition of proliferation and cell cycle-regulating proteins. 相似文献