全文获取类型
收费全文 | 132篇 |
免费 | 8篇 |
专业分类
140篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 10篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 13篇 |
2013年 | 13篇 |
2012年 | 13篇 |
2011年 | 9篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有140条查询结果,搜索用时 0 毫秒
1.
Virulent tubercle bacilli inhibit apoptosis to establish a safe environment within the host cells. Here, we report that NF-kappaB dependent antiapoptotic protein bfl-1/A1 plays an important role in this process. Both virulent and avirulent mycobacteria bearing THP-1 cells expressed considerable amount of bfl-1/A1 after 4 h of infection. However, after 48 h of infection, bfl-1/A1 expression was evident only in Mycobacterium tuberculosis H37Rv but not in M. tuberculosis H37Ra infected cells. When parallel experiments were performed with Human monocyte-derived macrophages (MDMs), differential expression of bfl-1/A1 mRNA was observed in case of M. tuberculosis H37Rv and M. tuberculosis H37Ra infection. siRNA mediated inhibition of bfl-1/A1 induced apoptosis in M. tuberculosis H37Rv infected THP-1 and MDMs. Reduction in intracellular mycobacterial growth was observed in bfl-1/A1 siRNA transfected, M. tuberculosis H37Rv infected THP-1 cells. Enhancement of phagosome-lysosome fusion was observed in bfl-1/A1 siRNA treated and M. tuberculosis H37Rv infected THP-1 cells. These results clearly indicated that differential expression of bfl-1/A1 in M. tuberculosis H37Rv and M. tuberculosis H37Ra infected THP-1 cells probably account for the difference in infection outcome. 相似文献
2.
3.
Parthenium hysterophorus L. an exotic, pernicious weed is considered as one of the most troublesome weeds for agricultural sector by virtue of its high ecological amplitude and adaptability. Microbes and their by-products are now proved to be a worthy alternative to toxic chemicals used for weed management. Alternaria macrospora MKPI was isolated from the parthenium leaves infected with leaf blight and found pathogenic to the weed. The herbicidal potential of cell free culture filtrate of A. macrospora MKP1 has been tested against parthenium by employing detached leaf bioassay and seed germination bioassay and a significant damage was exhibited by the cultural filtrate of pathogen to the parthenium leaves and seeds. 相似文献
4.
Saurabh Sudha Dhiman Dayanand Kalyani Sujit Sadashiv Jagtap Jung-Rim Haw Yun Chan Kang Jung-Kul Lee 《Applied microbiology and biotechnology》2013,97(3):1081-1091
Enhanced catalytic activities of different lignocellulases were obtained from Armillaria gemina under statistically optimized parameters using a jar fermenter. This strain showed maximum xylanase, endoglucanase, cellobiohydrolase, and β-glucosidase activities of 1,270, 146, 34, and 15 U mL?1, respectively. Purified A. gemina xylanase (AgXyl) has the highest catalytic efficiency (k cat/K m?=?1,440 mg?mL?1?s?1) ever reported for any fungal xylanase, highlighting the significance of the current study. We covalently immobilized the crude xylanase preparation onto functionalized silicon oxide nanoparticles, achieving 117 % immobilization efficiency. Further immobilization caused a shift in the optimal pH and temperature, along with a fourfold improvement in the half-life of crude AgXyl. Immobilized AgXyl gave 37.8 % higher production of xylooligosaccharides compared to free enzyme. After 17 cycles, the immobilized enzyme retained 92 % of the original activity, demonstrating its potential for the synthesis of xylooligosaccharides in industrial applications. 相似文献
5.
Heena Dhiman Matthias P. Gerstl David Ruckerbauer Michael Hanscho Heinz Himmelbauer Colin Clarke Niall Barron Jürgen Zanghellini Nicole Borth 《Biotechnology journal》2019,14(7)
The increasingdemandfor biopharmaceutical products drives the search for efficient cell factories that are able to sustainably support rapid growth, high productivity, and product quality. As these depend on energy generation, here the genomic variation in nuclear genes associated with mitochondria and energy metabolism and the mitochondrial genome of 14 cell lines is investigated. The variants called enable reliable tracing of lineages. Unique sequence variations are observed in cell lines adapted to grow in protein‐free media, enriched in signaling pathways or mitogen‐activated protein kinase 3. High‐producing cell lines bear unique mutations in nicotinamide adenine dinucleotide (NADH) dehydrogenase (ND2 and ND4) and in peroxisomal acyl‐CoA synthetase (ACSL4), involved in lipid metabolism. As phenotypes are determined not only by functional mutations, but also by the exquisite regulation of expression patterns, it is not surprising that ≈50% of the genes investigated here are found to be differentially methylated and thus epigenetically controlled, enabling a clear distinction of high producers, and cells adapted to a minimal, glutamine (Gln)‐free medium. Similar pathways are enriched as those identified by genome variation. This strengthens the hypothesis that these phenomena act together to define cell behavior. 相似文献
6.
7.
8.
Cellular and humoral immunity induced by Mycobacterium tuberculosis has led to identification of newer vaccine candidates, but despite this, many questions concerning the protection against tuberculosis remain unanswered. Recent progress in this field has centered on T cell subset responses and cytokines that these cells secrete. There has been a steady progress in identification and characterization of several classes of major mycobacterial proteins which includes secretory/export proteins, cell wall associated proteins, heat shock proteins and cytoplasmic proteins. The protein antigens are now believed to represent the key protective immunity inducing antigens in the bacillus. In this review, various mycobacterial protein antigens of vaccination potential are compared for their efficacy in light of current immunological knowledge. 相似文献
9.
A number of factors affect the infectivity of retroviruses. The effect of pH on infectivity and morphology of ecotropic moloney murine leukemia virus (MoMuLV) was determined in this work. The ecotropic MoMuLVs were found to remain infectious at a narrow pH range from 5.5 to 8.0. Our experiments indicated that the viruses were inactivated swiftly at lower or higher pH. Within 5 min of exposure to pH 4 about 95% of the viruses lost infectiousness. The viruses were completely inactivated after exposure to pH < 3 or pH >11 for 5 min. The inactivation of MoMuLV was irreversible. Electron microscopy revealed that ecotropic MoMuLV remained round-shaped at pH between 7.0 and 5. They became irregular with a convex head at pH < 4. At pH 2, virtually all virion particles were penetrated by stains, causing the accumulation of heavy metals inside the particles. The penetration of heavy metal inside the particles indicated the disassociation of the lipid bilayer of the viruses at low pH. A FACS-based screening strategy for selecting high-titer retrovirus producing cell lines is also presented in this report. 相似文献
10.
Ahlawat S Battan B Dhiman SS Sharma J Mandhan RP 《Journal of industrial microbiology & biotechnology》2007,34(12):763-770
A very high level of alkalophilic and thermostable pectinase and xylanase has been produced from newly isolated strains of
Bacillus subtilis and Bacillus pumilus respectively. Enzyme production for pectinase was carried out under SSF using combinations of cheap agricultural residues
while xylanase was produced under submerged fermentation using wheat bran as substrate to minimize the cost of production
of these enzymes Among the various substrates tested, the highest yield of pectinase production was observed by using combination
of WB + CW (6592 U/g of dry substrate) supplemented with 4% yeast extract when incubated at 37 °C for 72 h using deionized
water of pH 7.0 as moistening agent. The biobleaching effect of these cellulase free enzymes on kraft pulp was determined.
Both xylanase and pectinase showed stability over a broad range of pH from 6 to 10 and temperature from 55 to 70 °C. The bleaching
efficiency of the pectinase and xylanase on kraft pulp was maximum after 150 min at 60 °C using enzyme dosage of 5 IU/ml of
each enzyme at 10% pulp consistency with about 16% reduction in kappa number and 84% reduction in permanganate number. Enzyme
treated pulp when subjected to CDED1D2 steps, 25% reduction in chlorine consumption and upto 19% reduction in consumption of chlorine dioxide was observed for obtaining
the same %ISO brightness. Also an increase of 22 and 84% in whiteness and fluorescence respectively and a decrease of approximately
19% in the yellowness of the biotreated pulp were observed by pretreatment of the pulp with our enzymatic mixture. 相似文献