共查询到20条相似文献,搜索用时 31 毫秒
1.
Background
Sulphur compounds like cysteine, methionine and S-adenosylmethionine are essential for the viability of most cells. Thus many organisms have developed a complex regulatory circuit that governs the expression of enzymes involved in sulphur assimilation and metabolism. In the filamentous fungus Hypocrea jecorina (anamorph Trichoderma reesei) little is known about the participants in this circuit. 相似文献2.
Gaelle André Elise Haudecoeur Kaori Ohtani Tohru Shimizu Bruno Dupuy Isabelle Martin-Verstraete 《BMC microbiology》2010,10(1):234
Background
Cysteine has a crucial role in cellular physiology and its synthesis is tightly controlled due to its reactivity. However, little is known about the sulfur metabolism and its regulation in clostridia compared with other firmicutes. In Clostridium perfringens, the two-component system, VirR/VirS, controls the expression of the ubiG operon involved in methionine to cysteine conversion in addition to the expression of several toxin genes. The existence of links between the C. perfringens virulence regulon and sulfur metabolism prompted us to analyze this metabolism in more detail. 相似文献3.
Li Zhou Hongjie Wang Xing Zhong Yulan Jin Qing-Sheng Mi Ashok Sharma Richard A McIndoe Nikhil Garge Robert Podolsky Jin-Xiong She 《Genome biology》2008,9(7):R119
Background
CD8+ NKT-like cells are naturally occurring but rare T cells that express both T cell and natural killer cell markers. These cells may play key roles in establishing tolerance to self-antigens; however, their mechanism of action and molecular profiles are poorly characterized due to their low frequencies. We developed an efficient in vitro protocol to produce CD8+ T cells that express natural killer cell markers (CD8+ NKT-like cells) and extensively characterized their functional and molecular phenotypes using a variety of techniques. 相似文献4.
Axel Krinner Martin Hoffmann Markus Loeffler Dirk Drasdo Joerg Galle 《BMC systems biology》2010,4(1):73
Background
In vitro cultivated stem cell populations are in general heterogeneous with respect to their expression of differentiation markers. In hematopoietic progenitor populations, this heterogeneity has been shown to regenerate within days from isolated subpopulations defined by high or low marker expression. This kind of plasticity has been suggested to be a fundamental feature of mesenchymal stem cells (MSCs) as well. Here, we study MSC plasticity on the level of individual cells applying a multi-scale computer model that is based on the concept of noise-driven stem cell differentiation. 相似文献5.
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Shan Goh Andrea Camattari Daniel Ng Ruth Song Kevin Madden Janet Westpheling Victor VT Wong 《BMC biotechnology》2007,7(1):72
Background
The Actinomycete Actinosynnema pretiosum ssp. auranticum has commercial importance due to its production of ansamitocin P-3 (AP-3), a potent antitumor agent. One way to increase AP-3 production would be to constitutively express selected genes so as to relieve bottlenecks in the biosynthetic pathway; however, an integrative expression vector for A. pretiosum is lacking. The aim of this study was to construct a vector for heterologous gene expression in A. pretiosum. 相似文献7.
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Background
The expression of recombinant proteins in eukaryotic cells requires the fusion of the coding region to a promoter functional in the eukaryotic cell line. Viral promoters are very often used for this purpose. The preceding cloning procedures are usually performed in Escherichia coli and it is therefore of interest if the foreign promoter results in an expression of the gene in bacteria. In the case molecules toxic for humans are to be expressed, this knowledge is indispensable for the specification of safety measures. 相似文献10.
Arno Wegkamp Astrid E Mars Magda Faijes Douwe Molenaar Ric CH de Vos Sebastian MJ Klaus Andrew D Hanson Willem M de Vos Eddy J Smid 《Microbial cell factories》2010,9(1):100
Background
Using a functional genomics approach we addressed the impact of folate overproduction on metabolite formation and gene expression in Lactobacillus plantarum WCFS1. We focused specifically on the mechanism that reduces growth rates in folate-overproducing cells. 相似文献11.
Background
Rhizobia induce the formation on specific legumes of new organs, the root nodules, as a result of an elaborated developmental program involving the two partners. In order to contribute to a more global view of the genetics underlying this plant-microbe symbiosis, we have mined the recently determined Sinorhizobium meliloti genome sequence for genes potentially relevant to symbiosis. We describe here the construction and use of dedicated nylon macroarrays to study simultaneously the expression of 200 of these genes in a variety of environmental conditions, pertinent to symbiosis. 相似文献12.
Raffaele Lombardi Patrizia Circelli Maria Elena Villani Giampaolo Buriani Luca Nardi Valentina Coppola Linda Bianco Eugenio Benvenuto Marcello Donini Carla Marusic 《BMC biotechnology》2009,9(1):96
Background
In recent years, different HIV antigens have been successfully expressed in plants by either stable transformation or transient expression systems. Among HIV proteins, Nef is considered a promising target for the formulation of a multi-component vaccine due to its implication in the first steps of viral infection. Attempts to express Nef as a single protein product (not fused to a stabilizing protein) in transgenic plants resulted in disappointingly low yields (about 0.5% of total soluble protein). In this work we describe a transient expression system based on co-agroinfiltration of plant virus gene silencing suppressor proteins in Nicotiana benthamiana, followed by a two-step affinity purification protocol of plant-derived Nef. 相似文献13.
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Background
Despite extensive efforts devoted to predicting protein-coding genes in genome sequences, many bona fide genes have not been found and many existing gene models are not accurate in all sequenced eukaryote genomes. This situation is partly explained by the fact that gene prediction programs have been developed based on our incomplete understanding of gene feature information such as splicing and promoter characteristics. Additionally, full-length cDNAs of many genes and their isoforms are hard to obtain due to their low level or rare expression. In order to obtain full-length sequences of all protein-coding genes, alternative approaches are required. 相似文献15.
Background
The Salmonella AvrA gene is present in 80% of Salmonella enterica serovar strains. AvrA protein mimics the activities of some eukaryotic proteins and uses these activities to the pathogen's advantage by debilitating the target cells, such as intestinal epithelial cells. Therefore, it is important to understand how AvrA works in targeting eukaryotic signaling pathways in intestinal infection in vivo. In this study, we hypothesized that AvrA interacts with multiple stress pathways in eukaryotic cells to manipulate the host defense system. A whole genome approach combined with bioinformatics assays was used to investigate the in vivo genetic responses of the mouse colon to Salmonella with or without AvrA protein expression in the early stage (8 hours) and late stage (4 days). Specifically, we examined the gene expression profiles in mouse colon as it responded to pathogenic Salmonella stain SL1344 (with AvrA expression) or SB1117 (without AvrA expression). 相似文献16.
F. Mahboudi F. Barkhordari R.M. Godarzi S. Enayati F. Davami 《Journal of applied microbiology》2013,114(2):364-372
Aims
A novel chimeric‐truncated form of tissue‐type plasminogen activator (t‐PA) with improved fibrin affinity and resistance to PAI was successfully produced in CHO expression system during our previous studies. Considering advantages of prokaryotic expression systems, the aim in this study was to produce the novel protein in Escherichia coli (BL21) strain and compare the protein potency in batch and fed‐batch processes.Methods and Results
The expression cassette for the novel t‐PA was prepared in pET‐28a(+). The E. coli expression procedure was compared in traditional batch and newly developed fed batch, EnBase® Flo system. The protein was purified in soluble format, and potency results were identified using Chromolize t‐PA Assay Kit. The fed‐batch fermentation mode, coupled with a Ni‐NTA affinity purification procedure under native condition, resulted in higher amounts of soluble protein, and about a 30% of improvement in the specific activity of the resulted recombinant protein (46·66 IU mg?1) compared to traditional batch mode (35·8 IU mg?1).Conclusions
Considering the undeniable advantages of expression in the prokaryotic expression systems such as E. coli for recombinant protein production, applying alternative methods of cultivation is a promising approach. In this study, fed‐batch cultivation methods showed the potential to replace miss‐folded formats of protein with proper folded, soluble form with improved potency.Significance and Impact of the Study
Escherichia coli expression of recombinant proteins still counts for nearly 40% of marketed biopharmaceuticals. The major drawback of this system is the lack of appropriate post‐translational modifications, which may cause potency loss/decline. Therefore, applying alternative methods of cultivation as investigated here is a promising approach to overcome potency decrease problem in this protein production system. 相似文献17.
Background
B. subtilis is an important organism in the biotechnological application. The efficient expression system is desirable in production of recombinant gene products in B. subtilis. Recently, we developed a new inducible expression system in B. subtilis, which directed by B. subtilis maltose utilization operon promoter P glv . The system demonstrated high-level expression for target proteins in B. subtilis when induced by maltose. However, the system was markedly repressed by glucose. This limited the application of the system as a high-expression tool in biotechnology field. The aim of this study was to further improve the P glv promoter system and enhance its expression strength. 相似文献18.
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Background
In the past few years, both automated and manual high-throughput protein expression and purification has become an accessible means to rapidly screen and produce soluble proteins for structural and functional studies. However, many of the commercial vectors encoding different solubility tags require different cloning and purification steps for each vector, considerably slowing down expression screening. We have developed a set of E. coli expression vectors with different solubility tags that allow for parallel cloning from a single PCR product and can be purified using the same protocol. 相似文献20.
Krusch S Domann E Frings M Zelmer A Diener M Chakraborty T Weiss S 《The journal of gene medicine》2002,4(6):655-667