Microbial enzymes for oxidation of organic molecules

Enzymatic systems employed by microorganisms for oxidative transformation of various organic molecules include laccases, ligninases, tyrosinases, monooxygenases, and dioxygenases. Reactions performed by these enzymes play a significant role in maintaining the global carbon cycle through either transformation or complete mineralization of organic molecules. Additionally, oxidative enzymes are instrumental in modification or degradation of the ever-increasing man-made chemicals constantly released into our environment. Due to their inherent stereo- and regioselectivity and high efficiency, oxidative enzymes have attracted attention as potential biocatalysts for various biotechnological processes. Successful commercial application of these enzymes will be possible through employing new methodologies, such as use of organic solvents in the reaction mixtures, immobilization of either the intact microorganisms or isolated enzyme preparations on various supports, and genetic engineering technology.     

The Use of Baker's Yeast in the Generation of Asymmetric Centers to Produce Chiral Drugs and Other Compounds

ABSTRACT:?

This review gives a general idea about the importance of chiral carbon in medicine and a way to obtain chiral building blocks with Baker's yeast (Saccharomyces cerevisiae) or synthesis of medicaments and other organic compounds. Reactions with these microorganisms are cheaper and easier to be executed than with chemicals (e.g., organometallics). Examples of important and practical reactions catalyzed by enzymes inside Saccharomyces cerevisiae are given and probable mechanisms of action of these enzymes are shown. Although these microbes have advantages such as low cost and availability, there are some concerns that are necessary to be resolved, such as NAD(P)H dosage to choose strains more adequate for reduction reactions.     

Mycoremediation (bioremediation with fungi) – growing mushrooms to clean the earth

Abstract

Some of the prospects of using fungi, principally white-rot fungi, for cleaning contaminated land are surveyed. That white-rot fungi are so effective in degrading a wide range of organic molecules is due to their release of extra-cellular lignin-modifying enzymes, with a low substrate-specificity, so they can act upon various molecules that are broadly similar to lignin. The enzymes present in the system employed for degrading lignin include lignin-peroxidase (LiP), manganese peroxidase (MnP), various H₂O₂ producing enzymes and laccase. The degradation can be augmented by adding carbon sources such as sawdust, straw and corn cob at polluted sites.     

In situ light and phosphorus manipulations reveal potential role of biofilm algae in enhancing enzyme‐mediated decomposition of organic matter in streams

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Cloning of Fish Enzymes and Other Fish Protein Genes

ABSTRACT:?

Fish metabolism needs special enzymes that have maximum activity at very different conditions than their mammalian counterparts. Due to the differences in activity, these enzymes, especially cold-adapted proteases, could be used advantageously for the production of some foods. In addition to the enzymes, this review describes some other unique fish polypeptides such as antifreeze proteins, fluorescent proteins, antitumor peptides, antibiotics, and hormones, that have already been cloned and used in food processing, genetic engineering, medicine, and aquaculture. Recombinant DNA technology, which allows these biological molecules to be cloned and overexpressed in microorganisms is also described, highlighting innovative applications. The expected impact of cloning fish proteins in different fields of technology is discussed.     

Phytochemicals targeting matrix metalloproteinases regulating tissue degradation in inflammation and rheumatoid arthritis

PurposeMatrix metalloproteinases, zinc dependent proteolytic enzymes, have significant implications in extracellular matrix degradation associated with tissue damage in inflammation and Rheumatoid arthritis. Numerous orchestrated pathways affects instigation and blockade of metalloproteinases as well as various factors that increase the expression of MMPs including inflammatory cytokines, hormones and growth factors. Direct inhibition of these proteolytic enzymes or modulation of these pathways can provide protection against tissue destruction in inflammation and rheumatoid arthritis. Inclination towards use of plant derived phytochemicals to prevent tissue damage has been increasing day by day. Diversity of phytochemicals have been known to directly inhibit metalloproteinases. Hence, thorough knowledge of phytochemicals is very important in novel drug discovery.MethodsPresent communication evaluates various classes of phytochemicals, in effort to unveil the lead molecules as potential therapeutic agents, for prevention of MMPs mediated tissue damage in inflammation and rheumatoid arthritis. Data have been analyzed through different search engines.ResultsNumerous phytochemicals have been studied for their role as MMPs inhibitors which can be processed further to develop into useful drugs for the treatment of inflammation and rheumatoid arthritis.ConclusionIn search of new drugs, phytochemicals like flavonoids, glycosides, alkaloids, lignans & terpenes offer a wide canvas to develop into valuable forthcoming medicaments.     

Improved reactive aldehyde,salt and cadmium tolerance of transgenic barley due to the expression of aldo–keto reductase genes

Under various stress conditions, plant cells are exposed to oxidative damage which triggers lipid peroxidation. Lipid peroxide breakdown products include protein crosslinking reactive aldehydes. These are highly damaging to living cells. Stress-protective aldo–keto reductase (AKR) enzymes are able to recognise and modify these molecules, reducing their toxicity. AKRs not only modify reactive aldehydes but may synthesize osmoprotective sugar alcohols as well. The role of these mixed function enzymes was investigated under direct reactive aldehyde, heavy metal and salt stress conditions. Transgenic barley (Hordeum vulgare L.) plants constitutively expressing AKR enzymes derived from either thale cress (Arabidopsis thaliana) (AKR4C9) or alfalfa (Medicago sativa) (MsALR) were studied. Not only AKR4C9 but MsALR expressing plants were also found to produce more sorbitol than the non-transgenic (WT) barley. Salinity tolerance of genetically modified (GM) plants improved, presumably as a consequence of the enhanced sorbitol content. The MsALR enzyme expressing line (called 51) exhibited almost no symptoms of salt stress. Furthermore, both transgenes were shown to increase reactive aldehyde (glutaraldehyde) tolerance. Transgenic plants also exhibited better cadmium tolerance compared to WT, which was considered to be an effect of the reduction of reactive aldehyde molecules. Transgenic barley expressing either thale cress or alfalfa derived enzyme showed improved heavy metal and salt tolerance. Both can be explained by higher detoxifying and sugar alcohol producing activity. Based on the presented data, we consider AKRs as very effective stress-protective enzymes and their genes provide promising tools in the improvement of crops through gene technology.     

Dhanwantaram kashayam,an Ayurvedic polyherbal formulation,reduces oxidative radicals and reverts lipids profile towards normal in diabetic rats

BackgroundHyperglycemia and hyper oxidative stress are indicators of diabetes mellitus which is also accompanied with decreased levels of antioxidant enzymes. While oxidative stress is important in increasing insulin secretion and controlling blood sugar level at the same time excess oxidative stress leads to the destruction of beta cells of pancreas resulting in to low insulin production and hyperglycemia. A balance between the levels of oxidative radicals and insulin production is needed, but is not defined yet. Hyperglycemia also leads to hyperlipidemia which can contribute to various health conditions like cardiovascular diseases.ObjectivesThis study was designed to study the oxidative stress and lipid levels in diabetic rats. This also was designed to elucidate the effect of Dhanwantaram Kashayam, an Ayurvedic polyphenolic derived from plants on lipid metabolism and oxidative radical scavenging in diabetic rats.MethodsRats were made diabetic by injecting streptozotocin. Different enzymes involved in oxidative radical scavenging and lipid profiles including triglycerides, total cholesterol, free fatty acids and phospholipids were estimated using standard methods reported elsewhere.ResultsLevel of antioxidant enzymes were lower in diabetic rats compared to normal controls. Administration of Dhanwantaram Kashayam restored the enzyme activity as well as reduced levels of different lipids in diabetic rats.ConclusionsAdministration of Dhanwantaram Kashayam increased the activity levels of antioxidant enzymes and reduced the levels of total cholesterol, phospholipids and triglycerides. The results of this study point to the possibility of developing Dhanwantaram Kashayam as a dietary supplement which can alleviate the complications associated with diabetes or prevent them altogether.     

微塑料与土壤环境中微生物互作研究进展

作为环境中广泛存在的污染物,微塑料(microplastics)的相关研究备受关注。基于已有研究,本文综合分析了微塑料与土壤微生物(soil microorganisms)的互作关系,微塑料会通过直接或间接的方式影响微生物群落结构与多样性,影响的程度取决于微塑料的类型、剂量和形状。土壤微生物会通过形成表面生物膜和群落选择效应来适应微塑料这一外来物所引起的变化。本文还特别关注了微塑料的生物降解机理,同时探究了影响这一过程的因素,微生物首先会定殖在微塑料表面,分泌多种胞外酶在特定位点发挥作用,将聚合物转化成低聚物或单体,解聚的小分子进入胞内进一步分解代谢,而影响这一降解过程的因素除了分子量、密度、结晶度等微塑料自身理化性质,还包括一些生物因素和非生物因素对相关微生物生长代谢和酶活性的作用。未来研究应注重与实际环境的联系,在深入探究微塑料生物降解研究的同时,开发解决微塑料污染问题的新技术。     

Biotransformation: a green and efficient way of antioxidant synthesis

Antioxidant compounds play a vital role in human physiology. They prevent the oxidation of biomolecules by scavenging free radicals produced during physiochemical processes and/or as a result of several pathological states. A balance between the reactive oxygen species (free radicals) and antioxidants is essential for proper physiological conditions. Excessive free radicals cause oxidative stress which can lead to several human diseases. Therefore, synthesis of the effective antioxidants is crucial in managing the oxidative stress. Biotransformation has evolved as an effective technique for the production of structurally diverse molecules with a wide range of biological activities. This methodology surpasses the conventional chemical synthesis due to the fact that enzymes, being specific in nature, catalyze reactions affording products with excellent regio- and stereoselectivities. Structural transformation of various classes of compounds such as alkaloids, steroids, flavonoids, and terpenes has been carried out through this technique. Several bioactive molecules, especially those having antioxidant potential have also been synthesized by using different biotransformation techniques and enzymes. Hydroxylated, glycosylated, and acylated derivatives of phenols, flavonoids, cinnamates, and other molecules have proven abilities as potential antioxidants. A critical review of the biotransformation of these compounds into potent antioxidant metabolites is presented here.     

Mangiferin attenuates oxidative stress induced renal cell damage through activation of PI3K induced Akt and Nrf-2 mediated signaling pathways

BackgroundMangiferin is a polyphenolic xanthonoid with remarkable antioxidant activity. Oxidative stress plays the key role in tert-butyl hydroperoxide (tBHP) induced renal cell damage. In this scenario, we consider mangiferin, as a safe agent in tBHP induced renal cell death and rationalize its action systematically, in normal human kidney epithelial cells (NKE).MethodsNKE cells were exposed to 20 µM mangiferin for 2 h followed by 50 µM tBHP for 18 h. The effect on endogenous ROS production, antioxidant status (antioxidant enzymes and thiols), mitochondrial membrane potential, apoptotic signaling molecules, PI3K mediated signaling cascades and cell cycle progression were examined using various biochemical assays, FACS and immunoblot analyses.ResultstBHP exposure damaged the NKE cells and decreased its viability. It also elevated the intracellular ROS and other oxidative stress-related biomarkers within the cells. However, mangiferin dose dependently, exhibited significant protection against this oxidative cellular damage. Mangiferin inhibited tBHP induced activation of different pro-apoptotic signals and thus protected the renal cells against mitochondrial permeabilization. Further, mangiferin enhanced the expression of cell proliferative signaling cascade molecules, Cyclin d1, NFκB and antioxidant molecules HO-1, SOD2, by PI3K/Akt dependent pathway. However, the inhibitor of PI3K abolished mangiferin's protective activity.ConclusionsResults show Mangiferin maintains the intracellular anti-oxidant status, induces the expression of PI3K and its downstream molecules and shields NKE cells against the tBHP induced cytotoxicity.General significanceMangiferin can be indicated as a therapeutic agent in oxidative stress-mediated renal toxicity. This protective action of mangiferin primarily attributes to its potent antioxidant and antiapoptotic nature.     

Soil microalgae and cyanobacteria: the biotechnological potential in the maintenance of soil fertility and health

Abstract

The soil microbiota plays a major role in maintaining the nutrient balance, carbon sink, and soil health. Numerous studies reported on the function of microbiota such as plant growth-promoting bacteria and fungi in soil. Although microalgae and cyanobacteria are ubiquitous in soil, very less attention has been paid on the potential of these microorganisms. The indiscriminate use of various chemicals to enhance agricultural productivity led to serious consequences like structure instability, accumulation of toxic contaminants, etc., leading to an ecological imbalance between soil, plant, and microbiota. However, the significant role of microalgae and cyanobacteria in crop productivity and other potential options has been so far undermined. The intent of the present critical review is to highlight the significance of this unique group of microorganisms in terms of maintaining soil fertility and soil health. Beneficial soil ecological applications of these two groups in enhancing plant growth, establishing interrelationships among other microbes, and detoxifying chemical agents such as insecticides, herbicides, etc. through mutualistic cooperation by synthesizing enzymes and phytohormones are presented. Since recombinant technology involving genomic integration favors the development of useful traits in microalgae and cyanobacteria for their potential application in improvement of soil fertility and health, the merits and demerits of various such advanced methodologies associated in harnessing the biotechnological potential of these photosynthetic microorganisms for sustainable agriculture were also discussed.     

Physiology and Pathophysiology of Selectins,Integrins, and IgSf Cell Adhesion Molecules Focusing on Inflammation. A Paradigm Model on Infectious Endocarditis

Abstract

The development of adhesion bonds, either among cells or among cells and components of the extracellular matrix, is a crucial process. These interactions are mediated by some molecules collectively known as adhesion molecules (CAMs). CAMs are ubiquitously expressed proteins playing a central role in controlling cell migration, proliferation, survival, and apoptosis. Besides their key function in physiological maintenance of tissue integrity, CAMs play an eminent role in various pathological processes such as cardiovascular disorders, atherogenesis, atherosclerotic plaque progression and regulation of the inflammatory response. CAMs such as selectins, integrins, and immunoglobulin superfamily take part in interactions between leukocyte and vascular endothelium (leukocyte rolling, arrest, firm adhesion, migration). Experimental data and pathologic observations support the assumption that pathogenic microorganisms attach to vascular endothelial cells or sites of vascular injury initiating intravascular infections. In this review a paradigm focusing on cell adhesion molecules pathophysiology and infective endocarditis development is given.     

Hydrolytic activities of hydrolase enzymes from halophilic microorganisms

Biomass is normally processed using acidic or basic catalysts, which both have their drawbacks. One suitable alternative is the application of hydrolytic enzymes that can convert biomass into simpler molecules, which can be fermented and processed into biofuel. Hydrolytic enzymes include proteases, lipases, amylases, cellulases, mannanases, chitinases, and xylanases. To discover sources of these enzymes, 19 halophilic strains of microorganisms that are significantly resistant to high salt concentrations were analyzed. The objective of this research was to identify halophilic microorganisms that produce the target enzymes with high activities, and to characterize these enzymes according to their salt tolerances. The results obtained indicated that Pseudolateromonas phenolica, Micrococcus luteus, Pseudoalteromonas peptidolytica, Halomonas socia, Marinobacter maritimus, and Exiguobacterium aurantiacum strain 2 produced the highest protease, lipase, amylase, cellulase, mannanase, chitinase, and xylanase relative activities, respectively. Except for protease from P. phenolica, all the enzymes tested for salt resistance either maintained or increased their activities with increasing NaCl concentration.     

Structural and functional analyses of organic molecules regulating biomineralization

ABSTRACT

Biomineralization by living organisms are common phenomena observed everywhere. Molluskan shells are representative biominerals that have fine microstructures with controlled morphology, polymorph, and orientation of CaCO₃ crystals. A few organic molecules involved in the biominerals play important roles in the formation of such microstructures. Analyses of structure–function relationships for matrix proteins in biominerals revealed that almost all matrix proteins have an acidic region for the binding of calcium ion in CaCO₃ crystals and interaction domains for other organic molecules. On the other hand, biomineralization of metal nanoparticles by microorganisms were also investigated. Gold nanoparticles and quantum dots containing cadmium were successfully synthesized by bacteria or a fungus. The analyses of components revealed that glycolipids, oligosaccharides, and lactic acids have key roles to synthesize the gold nanoparticle in Lactobacillus casei as reductants and dispersants. These researches about biomineralization will give new insights for material and environmental sciences in the human society.     

Discovery,Characterisation and Applications of Enzymes from the Wood-forming Tissues of Poplar: Glycosyl Transferases and Xyloglucan Endotransglycosylases

Abstract

The Populus tremula x tremuloides Mich. expressed sequence tag (EST) database provides a rich and largely unexplored source of enzymes which can be developed into tools for wood fibre engineering, either by way of post-harvest processing or by transgenic technology. Enzyme discovery through functional genomics techniques, such as cDNA microarray analysis, is spotlighting particular carbohydrate-active enzymes which play a role in cell wall growth and development in wood-forming tissues. The cloning and heterologous expression of these enzymes is facilitating their study on a fundamental level, which lays the groundwork for advanced biotechnological applications.     

Chemical Synthesis of Oligonucleotides Containing Damaged Bases for Biological Studies

Since nucleic acids are organic molecules, even DNA, which carries genetic information, is subjected to various chemical reactions in cells. Alterations of the chemical structure of DNA, which are referred to as DNA damage or DNA lesions, induce mutations in the DNA sequences, which lead to carcinogenesis and cell death, unless they are restored by the repair systems in each organism. Formerly, DNA from bacteria and bacteriophages and DNA fragments treated with UV or γ radiation, alkylating or crosslinking agents, and other carcinogens were used as damaged DNA for biochemical studies. With these materials, however, it is difficult to understand the detailed mechanisms of mutagenesis and DNA repair. Recent progress in the chemical synthesis of oligonucleotides has enabled us to incorporate a specific lesion at a defined position within any sequence context. This method is especially important for studies on mutagenesis and translesion synthesis, which require highly pure templates, and for the structural biology of repair enzymes, which necessitates large amounts of substrate DNA as well as modified substrate analogs. In this review, the various phosphoramidite building blocks for the synthesis of lesion-containing oligodeoxyribonucleotides are described, and some examples of their applications to molecular and structural biology are presented.     

Potential of halotolerant and halophilic microorganisms for biotechnology

Halotolerant or halophilic microorganisms, able to live in saline environments, offer a multitude of actual or potential applications in various fields of biotechnology. The technical applications of bacteriorhodopsin comprise holography, spatial light modulators, optical computing, and optical memories. Compatible solutes are useful as stabilizers of biomolecules and whole cells, salt antagonists, or stress-protective agents. Biopolymers, such as biosurfactants and exopolysaccharides, are of interest for microbially enhanced oil recovery. Other useful biosubstances are enzymes, such as new isomerases and hydrolases, that are active and stable at high salt contents. Halotolerant microorganisms play an essential role in food biotechnology for the production of fermented food and food supplements. The degradation or transformation of a range of organic pollutants and the production of alternative energy are other fields of applications of these groups of extremophiles.     

Cyclic ureide and imide metabolism in microorganisms producing a -hydantoinase useful for -amino acid production

The microbial transformation of -5-monosubstituted hydantoins has been applied to industrial scale production of optically active amino acids. Hydantoinase and N-carbamoyl amino acid amidohydrolase, which are the key enzymes in this transformation, from various microorganisms have been studied extensively. Blastobacter sp. A17p-4, which was isolated for -amino acid production through hydantoin transformation, shows not only diverse cyclic ureide-metabolizing activities including those of -hydantoinase and N-carbamoyl- -amino acid amidohydrolase, but also cyclic imide-metabolizing activities. A recent study revealed the participation of -hydantoinase in the metabolism of cyclic imides and the existence of novel enzymes, imidase and half-amidase, in this bacterium. -hydantoinase functions in the metabolism of bulky cyclic imides, while imidase functions in that of simple cyclic imides in combination with half-amidase, which functions in the hydrolysis of the imidase reaction products, half-amides. Imidase and half-amidase are different from reported cyclic-amide-metabolizing enzymes, and are widely found in bacteria, yeasts and molds.     

Plasma membrane redox system protects cells against oxidative stress

Abstract

Aerobic organisms have developed defensive systems to survive in the presence of oxygen and its highly reactive species (ROS). The cellular mechanisms of protection against oxidative injury include: (i) specific enzymes, such as catalase, glutathione peroxidase and superoxide dismutase; (ii) small hydrophilic molecules, such as ascorbate, glutathione and uric acid; and (iii) hydrophobic agents, such as ubiquinone and α-tocopherol in membranes.¹ Among these, coenzyme Q (CoQ) is the only lipid-soluble antioxidant that can be synthesized in all organisms so far studied.