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Next Generation Industrial Biotechnology (NGIB) for PHA Production
Published in Martin Koller, The Handbook of Polyhydroxyalkanoates, 2020
PHBV has been well investigated for its application to bone substitutes, vascular grafts, absorbable surgical sutures, medical packaging, and drug carriers because of its excellent absorption capacity, biological origin, low cytotoxicity, piezoelectricity, and thermoplasticity [44]. Many genes of Halomonas spp. were genetically engineered to enhance PHBV production or regulate the ratio of 3-hydroxyvalerate (3HV). Knock-down of prpC encoding 2-methylcitrate synthase via a newly developed CRISPRi system, the percentage of 3HV in PHBV copolymers were controllable ranging from less than 1 to 13% [20]. Deletion on prpC gene increased the conversion efficiency of propionic acid to 3HV monomer in random PHBV copolymers from around 10% to almost 100% [19]. Overexpression of the threonine synthesis pathway and threonine dehydrogenase allows recombinant Halomonas TD08 to produce PHBV consisting of 4–6 mol-% 3HV [19]. In a recent study, deletions on prpC and sdhE encoding 2-methylcitrate synthase and succinate dehydrogenase assembly factor 2, respectively, combined with overexpressing of scpA, scpB and ppc, encoding methylmalonyl-CoA mutase, methylmalonyl-CoA decarboxylase, and phosphoenolpyruvate carboxylase, respectively, the engineered H. bluephagenesis TY194 (ΔsdhE, G7::Pporin-ppc) was found to synthesize 6.3 g/L CDM containing 65% PHBV consisting of 25 mol-% 3HV in PHBV when grown in glucose and gluconate in shake flasks [45].
Importance of Bacterial Biofilm in Bioremediation
Published in Pankaj Chowdhary, Abhay Raj, Contaminants and Clean Technologies, 2020
Rishi Pramod Babu, Soumya Pandit, Namita Khanna, Pankaj Chowdhary, Abhilasha Singh Mathuriya, Elvis Fosso-Kankeu
Recent examination has proved that the upregulation and the downregulation of genes are actively participated first in the attachment of the cells with the substratum. Nearly 22% of the genes were remediated and 16% were downregulated in the generation of Pseudomonas aeruginosa. algD, algU, rpoS, and the genes responsible for polyphosphokinase production were also upregulated in the formation of the P. aeruginosa biofilm. In Staphylococcus aureus, the genes programming the enzymes involved in glycolysis or fermentation, phosphoglycerate mutase, triphosphate, and alcohol dehydrogenase were upregulated. The cell-to-cell communication, also termed as QS, has been proven to play a very important role in cell attachment and removal from biofilms (Kalia et al., 2014). The development of biofilms on various surfaces is monitored by a density-dependent transcriptional activator protein that in concert acts with little autoinducers (AIs) (Kalia, 2014). Molecules induce the expression of target genes, which results in changes in chemical behavior. Once the collection of needed AIs is done, they provide intracellular communication to the coordinate gene expression, the physical differentiation, and the development response to the bacterial cells.
Sources of Natural Polymers from Microorganisms with Green Nanoparticles
Published in Satya Eswari Jujjavarapu, Krishna Mohan Poluri, Green Polymeric Nanocomposites, 2020
K. Chandrasekhar, Satya Eswari Jujjavarapu, Prasun Kumar, Gopalakrishnan Kumar, Potla Durthi Chandrasai, Enamala Manoj Kumar, Murthy Chavali
Streptococci are anaerobic microorganisms that utilize glucose as a substrate. They produce lactic acid as an intermediate metabolite. Streptococci also produce hyaluronic acid as a mucoid capsule around the cell. This helps the microorganism to escape from the host immune system. During streptococci growth, HA will be formed as a secondary metabolite. However, HA formation is liable through numerous physio-chemical factors that take account of genetic as well as nutritional factors. Streptococcus has the capability of producing HA as a secondary metabolite in aerobic conditions as well as in anaerobic circumstance. Definite strains of streptococcus yield HA during a specific period in their lifespan. The same microorganism produces an enzyme named hyaluronidase which has the capability of degrading the accumulated or already produced HA inside the cell (Tiwari & Bahadur, 2019; Valverde et al., 2019). The selection of a suitable strain for the production of HA is a crucial step and we should carefully select the appropriate strain to get a higher yield. Different types of enzymes involved in HA production through fermentation (biosynthesis) process are phosphoglucomutase, pyrophosphorylase, UDP, glucose dehydrogenase, hyaluronate synthase, pyrophosphorylase, acetyltransferase, mutase, and amidotransferase (Valverde et al., 2019).
Synthesis and evaluation of antimicrobial, antitubercular and anticancer activities of benzimidazole derivatives
Published in Egyptian Journal of Basic and Applied Sciences, 2018
Snehlata Yadav, Balasubramanian Narasimhan, Siong Meng Lim, Kalavathy Ramasamy, Mani Vasudevan, Syed Adnan Ali Shah, Abhishek Mathur
The results of mycobacterial enzyme assays were expressed in terms of percent inhibition of mycobacterial enzymes i.e., isocitrate lyase, chorismate mutase and pantothenate synthetase, by the mycobacterium. The inhibition of the enzyme activity by the tested compounds was less than that of streptomycin sulphate used as positive control (Table 5). Compound 19 emerged as the best compound that inhibited the mycobacterial isocitrate lyase, pantothenate synthetase and chorismate mutase to 67.56%, 53.45% and 47.56% respectively which was comparable to inhibition of 75.12%, 77.06%, and 79.56%, respectively by streptomycin sulphate.
Studies on the interaction of aquacobalamin with cysteinesulfinic and cysteic acids, hypotaurine and taurine
Published in Journal of Coordination Chemistry, 2018
Ilia A. Dereven’kov, Lubov V. Tsaba, Elizaveta A. Pokrovskaya, Sergei V. Makarov
Cobalamins (Cbls; Figure 1A) are important cobalt complexes involved in numerous processes in vivo [1], some of which became known only recently [2]. In mammals, Cbls serve as cofactors of two enzymatic systems, that is, methionine synthase and methylmalonyl-CoA mutase [1]. Moreover, Cbls are versatile targets for chemical modification, opening new areas of application in medicine [3, 4]. In the human body, Cbls and their derivatives participate in the set of redox and binding reactions [5, 6], which finally determine their biological effect.