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Processes for Overproduction of Microbial Metabolites for Industrial Applications
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
Whereas feedback inhibition results in the reduction of the activity of an already synthesized enzyme, feedback repression deals with a reduction in the rate of synthesis of the enzymes. In enzymes that are affected by feedback repression, the regulator gene (R) is said to produce a protein aporepressor which is inactive until it is attached to corepressor, which is the end-product of the biosynthetic pathway. The activated repressor protein then interacts with the operator gene (O) and prevents transcription of the structural genes (S) on to mRNA. A derivative of the end-product may also bring about feedback repression. It is particularly active in stopping the overproduction of vitamins which are required only in small amounts (see Fig. 6.1).
Analysis of polysaccharide hydrolases secreted by Aspergillus flavipes FP-500 on corn cobs and wheat bran as complex carbon sources
Published in Preparative Biochemistry & Biotechnology, 2020
Lizzete Ruth Torres-Barajas, María Teresa Alvarez-Zúñiga, Guillermo Mendoza-Hernández, Guillermo Aguilar-Osorio
Urease (urea amidohydrolase; EC 3.5.1.5) catalyzes the hydrolysis of urea to produce ammonia and carbamate. The latter is further hydrolyzed to yield carbonic acid and ammonia.[67] The urease presence was first reported in 1903, this enzyme has a role in the use of urea as a sole nitrogen source and is of great industrial interest.[68] Urease is not inducible, but it is subjected to nitrogen regulation and its presence is related to the areA regulator gene, which has a pleiotropic effect on carbon and nitrogen catabolism.[69] Urea catabolism has relevance because it has been reported that urease is a virulence factor in fungi and bacteria.[70] A urease was only found in the secretome of A. flavipes FP-500 in CC.
Expression profiles of long non-coding RNA in mouse lung tissue exposed to radon
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Jihua Nie, Jing Wu, Zhihai Chen, Yang Jiao, Jie Zhang, Hailin Tian, Jianxiang Li, Jian Tong
The lncRNA play crucial role in gene regulation through multiple mechanisms. These mechanisms include post-transcriptional regulation, organization of protein complexes, cell-cell signaling and regulation of proteins (Flintoft 2013; Geisler and Coller 2013). The results from microarray analysis and heat map in this study showed upregulation of LncRNA FR350376 was found to bind with PDX1 and regulate CYP27B1. In addition, the upregulated LncRNA FR192077 was noted to bind with the proteins MYC and NEM2 which might enhance carcinogenesis. Proto-oncogene Myc a regulator gene that codes for a transcription factor was shown to be involved in various human tumors (Brooks and Hurley 2009; Dang 2012). Yao et al. (2014) reported that c-Myc bound with nucleoside diphosphate kinase 2 (NME2) was involved in regulating tumor cell proliferation. In agreement with our findings radon-mediated lung damage was associated with increased binding of this gas to MYC transcription factor. Data thus suggest that the radon-induced alterations in transcription factor binding may also be associated with pulmonary carcinogenesis. However, further experiments are required to establish the involvement of lncRNA-transcript factor-mRNA network in the adverse pulmonary effects observed following radon exposure.
The growth and pluripotency of mesenchymal stem cell on the biodegradable polyurethane synthesized with ferric catalyst
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Qianqian Wei, Jiachang Jin, Xinyuan Wang, Qijun Shen, Mi Zhou, Shizhong Bu, Yabin Zhu
c-MYC is a regulator gene that codes for multi-functional, nuclear phosphoprotein that plays a role in cell cycle progression, apoptosis and cellular transformation. Its over expression stimulates gene amplification through DNA over-replication, leading cells’ mutation, even to be cancer cells [22]. In this work, the expression level of c-MYC was tested after cells were cultured for 14 d. Both cells on CPU and CPU-SF were much down-regulated as the cells on TCPS, hinting that cells on both substrates maintained the normal growth and transformation. All these results of RT-PCR analyses verified that the chemistry of polymers synthesized with ferric catalyst and surface modified by SF grafting with aminolysis and GA cross-linking enhanced cell-substratum interaction and strengthen the material’s biocompatibility.