排序方式: 共有77条查询结果,搜索用时 203 毫秒
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Mohsen Karbalaei Seyed A. Rezaee Hadi Farsiani 《Journal of cellular physiology》2020,235(9):5867-5881
One of the most important branches of genetic engineering is the expression of recombinant proteins using biological expression systems. Nowadays, different expression systems are used for the production of recombinant proteins including bacteria, yeasts, molds, mammals, plants, and insects. Yeast expression systems such as Saccharomyces cerevisiae (S. cerevisiae) and Pichia pastoris (P. pastoris) are more popular. P. pastoris expression system is one of the most popular and standard tools for the production of recombinant protein in molecular biology. Overall, the benefits of protein production by P. pastoris system include appropriate folding (in the endoplasmic reticulum) and secretion (by Kex2 as signal peptidase) of recombinant proteins to the external environment of the cell. Moreover, in the P. pastoris expression system due to its limited production of endogenous secretory proteins, the purification of recombinant protein is easy. It is also considered a unique host for the expression of subunit vaccines which could significantly affect the growing market of medical biotechnology. Although P. pastoris expression systems are impressive and easy to use with well-defined process protocols, some degree of process optimization is required to achieve maximum production of the target proteins. Methanol and sorbitol concentration, Mut forms, temperature and incubation time have to be adjusted to obtain optimal conditions, which might vary among different strains and externally expressed protein. Eventually, optimal conditions for the production of a recombinant protein in P. pastoris expression system differ according to the target protein. 相似文献
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Fariba Rezaee Stephanie L. Rellick Giovanni Piedimonte Stephen M. Akers Heather A. O'Leary Karen Martin Michael D. Craig Laura F. Gibson 《PloS one》2010,5(3)
Background
The host''s response to infection is characterized by altered levels of neurotrophins and an influx of inflammatory cells to sites of injured tissue. Progenitor cells that give rise to the differentiated cellular mediators of inflammation are derived from bone marrow progenitor cells where their development is regulated, in part, by cues from bone marrow stromal cells (BMSC). As such, alteration of BMSC function in response to elevated systemic mediators has the potential to alter their function in biologically relevant ways, including downstream alteration of cytokine production that influences hematopoietic development.Methodology/Principal Findings
In the current study we investigated BMSC neurotrophin receptor expression by flow cytometric analysis to determine differences in expression as well as potential to respond to NGF or BDNF. Intracellular signaling subsequent to neurotrophin stimulation of BMSC was analyzed by western blot, microarray analysis, confocal microscopy and real-time PCR. Analysis of BMSC Interleukin-6 (IL-6) expression was completed using ELISA and real-time PCR.Conclusion
BMSC established from different individuals had distinct expression profiles of the neurotrophin receptors, TrkA, TrkB, TrkC, and p75NTR. These receptors were functional, demonstrated by an increase in Akt-phosphorylation following BMSC exposure to recombinant NGF or BDNF. Neurotrophin stimulation of BMSC resulted in increased IL-6 gene and protein expression which required activation of ERK and p38 MAPK signaling, but was not mediated by the NFκB pathway. BMSC response to neurotrophins, including the up-regulation of IL-6, may alter their support of hematopoiesis and regulate the availability of inflammatory cells for migration to sites of injury or infection. As such, these studies are relevant to the growing appreciation of the interplay between neurotropic mediators and the regulation of hematopoiesis. 相似文献44.
Razzaghi-Abyaneh M Shams-Ghahfarokhi M Allameh A Kazeroon-Shiri A Ranjbar-Bahadori S Mirzahoseini H Rezaee MB 《Mycopathologia》2006,161(3):183-192
Soil isolates of Aspergillus section Flavi from Mazandaran and Semnan provinces with totally different climatic conditions in Iran were examined for aflatoxins (AFs;
B and G types), cyclopiazonic acid (CPA) and sclerotia production. A total of 66 Aspergillus flavus group strains were identified from three species viz. Aspergillus flavus, Aspergillus parasiticus and Aspergillus nomius in both locations. A. flavus (87.9%) was found to be the prominent species followed by A. nomius (9.1%) and A. parasiticus (3.0%). Only 27.5% of A. flavus isolates were aflatoxigenic (B1 or B1 and B2), out of which approximately 75% were capable to producing CPA. All the A. parasiticus and A. nomius isolates produced AFs of both B (B1 and B2) and G (G1 and G2) types, but did not produce CPA. Sclerotia production was observed in only 4 isolates of A. flavus among all 66 isolates from three identified species. A. flavus isolates were classified into various chemotypes based on the ability to produce aflatoxins and CPA. In this study, a new
naturally occurring toxigenic A. flavus chemotype comprising of two strains capable of producing more AFB2 than AFB1 has been identified. A relatively larger proportion of aflatoxigenic A. flavus strains were isolated from corn field soils of Mazandaran province which indicate a possible relationship between high levels
of relative humidity and the incidence of aflatoxin-producing fungi. The importance of incidence of Aspergillus section Flavi in corn field soils regard to their mycotoxin production profiles and crop contamination with special reference to climatic
conditions is discussed. 相似文献
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Mehdi Razzaghi-Abyaneh Reza Saberi Anosheh Sharifan Mohammad-Bagher Rezaee Roghayeh Seifili Seyed-Ibrahim Hosseini Masoomeh Shams-Ghahfarokhi Mehdi Nikkhah Ismail Saberi Akram Amani 《Mycotoxin Research》2013,29(4):261-269
The ethyl acetate extract of leaves, seeds and flowers of Heracleum persicum, a medicinal plant of Iran (family Apiaceae) inhibited growth and aflatoxin (AF) production of Aspergillus parasiticus. On the basis of total dry weight growth inhibition by the leaf extract ranged from 17.1 to 36.9 %, by the flower extract from 32.2 to 75.6 %, and by the seed extract from 27.5 to 74.9 %. Production of AFB1 and AFG1 was inhibited in a dose-dependent manner, with a reduction of 88.5–100 % at the highest concentration of 8,000 μg/ml tested. The flower extract decreased ergosterol content of hyphae most significantly. Electron microscopy further revealed structural defects in the treated A. parasiticus including disruption of cytoplasmic membranous compartments, detachment of plasma membrane from the cell wall, and disorganization of hyphal compartments. Collapsed hyphae without conidiation, shorter branches and undifferentiated hyphal tips were also evident. The results indicate that H. persicum extract exerts antifungal and anti-AF activities by disrupting plasma membrane integrity and permeability mainly through interference with ergosterol biosynthesis. These results show that H. persicum can serve as a potent and safe alternative for inhibiting toxigenic aspergilli growth and thus preventing AF contamination of foods and feeds. 相似文献
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Sahand Jorfi Abbas Rezaee Ghasem-Ali Mobeh-Ali Nemat Alah Jaafarzadeh 《Soil & Sediment Contamination》2013,22(8):890-911
Biosurfactants are considered to facilitate PAHs dissolution in soil slurries for bioremediation applications. In this work, the carbon and nitrogen sources, pH, C/N ratio, and salinity, were considered for optimization of biosurfactant production by Pseudomonas aeruginosa SP4 isolate to enhance pyrene removal from the contaminated soil. Analysis of ANOVA indicated that the carbon source was the most effective factor, followed by pH, nitrogen source, C/N ratio, and salinity. Taguchi experimental design proposed the optimum operating conditions of olive oil, NH4NO3, C/N ratio of 5, salinity of 0.5%, and pH 7. Applying the conditions determined by Taguchi design led to a production yield of 452 mg L?1 (13% improvement) at the optimum conditions. The main characteristics of produced biosurfactant included the critical micelle concentration (CMC) of 60 mg L?1 and liquid medium surface tension of 29.5 mN m?1. Produced biosurfactant was used for bioremediation of soil artificially contaminated with 500 mg kg?1 of pyrene. Following the addition of 250 mg L?1 biosurfactant, the pyrene removal of 84.6% was obtained compared to 59.8% for control sample without any surfactant. 相似文献
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Four new symmetric mixed-chelate dinuclear complexes type [Cu2(L)2(TAE)]X2, where TAE = tetraacetylethane; L = N,N-dimethyl-N′-benzylethylenediamine (L1) or N,N′-dibenylethylenediamine (L2); X = ClO4 or BPh4 have been synthesized and characterized on the bases of elemental analysis, spectroscopic and conductance measurements. The X-ray crystal analysis of [Cu2(L1)2(TAE)](ClO4)2 demonstrated that the two copper(II) ions are not equivalent. The axial position of the first copper is occupied by a ClO4− ion with a square pyramidal geometry whereas; the second copper ion resides in an octahedral environment determined by two perchlorate anions. However, in solution, the perchlorate ions are driven out by solvent molecules leading to their solvatochromism. The solvatochromism of the complexes were investigated in various organic solvents and also were compared with those of the corresponding mononuclear complexes [Cu(L)(acac)]ClO4. Their solvatochromism were also investigated with different solvent parameters models using stepwise multiple linear regression (SMLR) method. The results suggested that the DN parameter of the solvent has the dominate contribution to the shift of the d-d absorption band of the complexes. The results demonstrated that the complexes with counter ions of BPh4 are more solvatochromic in very weak donor solvents owing to their disinclination in ion-pair formation. 相似文献
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Ghada Kchour SA Rahim Rezaee Reza Farid Akram Ghantous Houshang Rafatpana Mahdi Tarhini Mohamad-Mehdi Kooshyar Hiba El Hajj Fadwa Berry Roudaina Nasser Abbas Shirdel Zeina Dassouki Mohamad Ezzedine Hossein Rahimi Ardeshir Ghavamzadeh Hugues de Thé Olivier Hermine Mahmoud Mahmoudi Ali Bazarbachi 《Retrovirology》2014,11(Z1):O4
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Johannes HM Levels Boris Bleijlevens Farhad Rezaee Johannes MFG Aerts Joost CM Meijers 《Proteome science》2007,5(1):15-8