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排序方式: 共有816条查询结果,搜索用时 140 毫秒
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Shuchi H. Desai Christine A. Rabinovitch-Deere Yohei Tashiro Shota Atsumi 《Applied microbiology and biotechnology》2014,98(8):3727-3736
Converting lignocellulosics into biofuels remains a promising route for biofuel production. To facilitate strain development for specificity and productivity of cellulosic biofuel production, a user friendly Escherichia coli host was engineered to produce isobutanol, a drop-in biofuel candidate, from cellobiose. A beta-glucosidase was expressed extracellularly by either excretion into the media, or anchoring to the cell membrane. The excretion system allowed for E. coli to grow with cellobiose as a sole carbon source at rates comparable to those with glucose. The system was then combined with isobutanol production genes in three different configurations to determine whether gene arrangement affected isobutanol production. The most productive strain converted cellobiose to isobutanol in titers of 7.64?±?0.19 g/L with a productivity of 0.16 g/L/h. These results demonstrate that efficient cellobiose degradation and isobutanol production can be achieved by a single organism, and provide insight for optimization of strains for future use in a consolidated bioprocessing system for renewable production of isobutanol. 相似文献
3.
The mechanism of mutagenesis induced by 2-amino-N6-hydroxyadenine (AHA) and its deoxyriboside (AHAdR) was studied by determining the nucleotide sequences of phage M13mp2 mutant DNA samples. Mutations in the lac promoter-lacZ alpha region of the phage were induced by addition of this agent to culture media in which the phage was growing inside the host bacteria. The spectrum of spontaneous mutation was also investigated. The induced sequence changes were mostly base transitions (80% with AHA and 90% with AHAdR). A few single-base deletions and additions were detected, but they were ascribable to spontaneous mutations. These results are consistent with the incorporation type mechanism proposed by Janion (this issue). In the Ames Salmonella assay, both AHA and AHAdR showed strong mutagenicity in strain TA100 but no activity in TA98. 相似文献
4.
DNA amplification in multidrug, cross-resistant Chinese hamster ovary cells: molecular characterization and cytogenetic localization of the amplified DNA 总被引:2,自引:0,他引:2 下载免费PDF全文
Vincristine-resistant (VCR) Chinese hamster ovary (CHO) cells have been established by stepwise selection in increasing concentrations of vincristine. These cells exhibit multidrug cross-resistance to a number of drugs that have no structural or functional similarities. Cytogenetic analyses of resistant cells revealed the presence of double minutes and expanded chromosomal segments, thus implicating gene amplification as a possible mechanism of resistance. An amplified DNA segment isolated from other multidrug cross-resistant CHO cell lines (Roninson, I. B., H. T. Abelson, D. E. Housman, N. Howell, and A. Varshavsky, 1984, Nature (Lond.), 309:626-628) is also amplified in our VCR lines. This DNA segment was used as a probe to screen a cosmid library of VCR genomic DNA, and overlapping clones were retrieved. All of these segments, totaling approximately 45 kilobases (kb), were amplified in VCR cells. Using in situ hybridization, we localized the amplification domain to the long arm of CHO chromosome 1 or Z1. Northern hybridization analysis revealed that a 4.3-kb mRNA was encoded by this amplified DNA domain and was over-produced in the VCR cells. Suggestions for the involvement of these amplified DNA segments in the acquisition of multidrug cross-resistance in animal cells are also presented. 相似文献
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6.
Sumitomo Shinichiro Tatemoto Yukihiro Fukui Shin Nakamura Taka-aki Fukushima Shoji Ito Nobuyuki Mori Masahiko 《Virchows Archiv. B, Cell pathology including molecular pathology》1985,49(1):395-399
Virchows Archiv B Cell Pathology - Paget cells from cases of mammary and extramammary Paget’s disease were examined for carcinoembryonic antigen (CEA) and CEA-related antigens by the... 相似文献
7.
Structural gene and complete amino acid sequence of Pseudomonas aeruginosa IFO 3455 elastase. 总被引:21,自引:8,他引:13 下载免费PDF全文
J Fukushima S Yamamoto K Morihara Y Atsumi H Takeuchi S Kawamoto K Okuda 《Journal of bacteriology》1989,171(3):1698-1704
The DNA encoding the elastase of Pseudomonas aeruginosa IFO 3455 was cloned, and its complete nucleotide sequence was determined. When the cloned gene was ligated to pUC18, the Escherichia coli expression vector, bacteria carrying the gene exhibited high levels of both elastase activity and elastase antigens. The amino acid sequence, deduced from the nucleotide sequence, revealed that the mature elastase consisted of 301 amino acids with a relative molecular mass of 32,926 daltons. The amino acid composition predicted from the DNA sequence was quite similar to the chemically determined composition of purified elastase reported previously. We also observed nucleotide sequence encoding a signal peptide and "pro" sequence consisting of 197 amino acids upstream from the mature elastase protein gene. The amino acid sequence analysis revealed that both the N-terminal sequence of the purified elastase and the N-terminal side sequences of the C-terminal tryptic peptide as well as the internal lysyl peptide fragment were completely identical to the deduced amino acid sequences. The pattern of identity of amino acid sequences was quite evident in the regions that include structurally and functionally important residues of Bacillus subtilis thermolysin. 相似文献
8.
Shinichiro Nakamura Wijit Kiatipattanasakul Hiroyuki Nakayama Fumiko Ono Ippei Sakakibara Yasuhiro Yoshikawa Naoaki Goto Kunio Doi 《Journal of medical primatology》1996,25(4):294-300
Abstract: In this study, we immunohistochemically examined the several constituents of senile plaques (SPs) and cerebral amyloid angiopathy (CAA) in aged cynomolgus monkeys. Apolipoprotein E (apoE) deposited in all mature plaques and CAA, and in half of the diffuse plaques. Alpha-1-antichymotripsin (αACT) deposited in half of the mature plaques and in one third of the CAA. Amyloid precursor protein (APP), ubiquitin (Ub), and microtubule-associated protein-2 (MAP-2) accumulated in the swollen neurites of mature plaques. Glial fibrillary acidic protein (GFAP) was detected in the astrocytes and their processes surrounding the mature plaques. Tau was detected in neither the SPs nor CAA. Therefore, mature plaques involved extracellular Aβ, apoE, and αACT, and also astrocytes and swollen neurites. However, diffuse plaques involved only extracellular Aβ and apoE. Since these features, except for tau, were consistent with those in humans, this animal model will be useful for studying the pathogenesis of cerebral amyloid deposition. 相似文献
9.
Shimomura Shoji; Liu Wei; Inohara Naohiro; Watanabe Shinichiro; Futai Masamitsu 《Plant & cell physiology》1993,34(4):633-637
A genomic clone encoding an auxin-binding protein (ABP) fromthe endoplasmic reticulum was isolated from Arabidopsis thaliana.The ABP gene consisted of 5 exons and 4 introns and encodeda polypeptide of 198 residues. A gene encoding the 7SL RNA ofthe signal recognition particle was located downstream of theABP gene.
4Recipient of a scholarship from the National Education Commission,People's Republic of China. 相似文献
10.
Evaluation of Superoxide Scavenging Activities of Hamamelis Extract and Hamamelitannin 总被引:2,自引:0,他引:2
Hamamelitannin, which is a component of bark extract of hamamelis (Hamamelis virginior L.), was found to be a potent scavenger of superoxide anion radicals. Superoxide anion scavenging activity of the compound was evaluated by ESR-spin trap method using DMPO (5,5'-dimethyl-1-pyrroline-N-oxide) as a spin trapping agent. The IC50 value (the concentration producing 50% inhibition of superoxide anion radicals) of hamamelitannin was found to be 1.38 ± 0.06 μM much lower than that of ascorbic acid (23.31 ± 2.23 μM). Supporting the superoxide scavenging activity of hamamelitannin, the compound showed both suppresive ability against depolymelization of hyaluronic acid and protective ability against cytotoxicity induced by superoxide anion radicals. Hamamelitannin increased the survival rate of fibroblast to 85.5 ± 3.3%, compared with that of control (27.2 ± 4.3%). 相似文献