Applied Biochemistry and Microbiology最新文献

Abstract

In this study, the fraction of the Hemiscorpius lepturus scorpion venom was subjected. The two bioactive fractions (F2 and F4) were separated and collected by RP-HPLC. Next, the cytotoxicity of F2 and F4 against human red blood cells and MCF-7 cell line was investigated. The expression levels of Bax, Bcl-2, and p53 genes in cancer cells treated with fractions were determined. In order to evaluate the effects of the two extract fractions, breast cancer was induced in BALB-c mice developed by the injection of MCF-7 cells. Following the intraperitoneal injection of F2 and F4 into mice, the levels of IFN-γ and IL-4 were measured using ELISA. The effects of fractions on the survival of MCF-7 cancer cells were significant compared to normal cells (p < 0.001), while they had no significant hemolysis activity against red blood cells (p > 0.05). The results showed that the expression of Bax and p53 was increased in MCF-7 cells treated with fractions compared to control cells without treatment, while the expression of Bcl-2 was decreased. The results of the in vivo analysis showed that the level of IFN-γ was increased, whereas the level of IL-4 was significantly reduced in mice treated with F2 and F4 at the concentrations of 5 and 10 mg/kg compared to control animals (p < 0.0001). Based on the results, two extract fractions of H. lepturus scorpion venom exert anti-cancer properties, and they are able to modulate the immune system and induce apoptosis in cancer cells.

Abstract

Water contamination by Remazol Brilliant Blue R (RBBR) can cause harmful effects on aquatic organisms due to its toxicity and recalcitrance in the environment. This study aimed to employ the oil palm fibers (OPFs)-immobilized white-rot fungus Trametes hirsuta AK04 to decolorize this dye and assess the alternative utilization of fungal-treated OPFs wastes. The fungus was able to utilize RBBR as a sole carbon and energy source. However, the decolorization efficiency was markedly enhanced by the supplementation of glucose as co-substrates. Veratyl alcohol (VA) was the best inducer to enhance the activities of laccase and manganese peroxidase associated with the decolorizing activity. The addition of 0.1 mM of VA along with glucose could accelerate the initial decolorization rate by the immobilized fungus, reaching 97% dye removal in 12 h. Fourier-transform infrared spectroscopy detected changes in the functional groups of dye and the formation of the degradation products, as well as changes within lignin and hemicellulose molecules in OPFs after decolorization. Sequentially, the fungal pretreatment of OPFs for 7–14 days resulted in increased lignin degradation and cellulose content, suggesting the possible use of treated OPFs as substrates for the further production of biofuels and other valuable products.

Abstract

People have become conscious about recycling or reusing many things they use in the 21st century because diminishing vital resources make it necessary, both personally and socially. The evaluation of waste is also critical in terms of national economies. In this study, starch dicarboxylic compounds were synthesized using waste potato peels (WPP) in the presence of sodium hypophosphite monohydrate as a catalyst for the formation of the ester cross-links. Adipic acid, succinic acid, and glutaric acid were employed with waste potato starch (WPS) to obtain cross-linked samples: WPS-A, WPS-S, and WPS-G, respectively. The obtained compounds were characterized by attenuated total reflectance Fourier transform infrared (FTIR-ATR), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD), and their cytotoxicity properties were investigated. The biocompatibility of the obtained WPS-dicarboxylic acid compounds against NIH-3T3 and L929 murine fibroblast cells with MTT assay was determined. Studies have shown that these compounds do not harm healthy cells and are found to be bioavailable.

Abstract

Fibrobacter succinogenes is a major cellulolytic anaerobic bacterium in the gut of herbivores and possesses genes with a wide range of hemicellulolytic activities. Endo-l,4-β-xylanase (EC.3.2.1.8) is a key member of the xylanolytic enzyme system and is widely used in animal feed, food, papermaking and medicine. In this research, the nucleotide-optimized endo-l,4-β-xylanase gene Xynm derived from the Fisuc_2442 gene of F. succinogenes was expressed in Pichia pastoris GS115. Carbon sources were optimized to facilitate recombinant xylanase Xynm production in high-cell-density fermentation. Characterization of the enzymatic properties of Xynm showed that it was overexpressed in P. pastoris by high-cell-density fermentation. Xynm had high specific activities toward various xylose polymers but low activity toward glucose-based polysaccharides. By methanol or a mixture of sorbitol/methanol (2 : 20 (wt/vol)) induction, the maximum specific activity of 6382 and 13821 U/mg protein was achieved with wheat flour arabinoxylan (high viscosity) as the substrate, and the maximum biomass was 111 and 161 g/L, respectively. Xynm exhibited optimal catalytic activity at pH 5.5 and 37°C and maintained over 80% of the initial activity after incubation at pH from 4.5 to 6.5 or from 10 to 50°C for 1 h. The enzyme activity was increased by Ba²⁺ and inhibited by Fe²⁺, Zn²⁺, and Ag⁺. Compared with corn, Xynm hydrolyzed wheat and released more reducing sugars. In summary, Xynm has high enzyme activity and moderate reaction conditions and shows promising application prospects for animal husbandry to improve the digestion of plant feedstuffs.

The biosynthesis of succinic acid from glucose by the previously engineered E. coli strain SUC1.0 (pMW119-kgd) (MG1655 ∆ackA-pta, ∆poxB, ∆ldhA, ∆adhE, ∆ptsG, P_Lglk, P_tacgalP, ∆aceBAK, ∆glcB, ∆sdhAB, pMW119-kgd) was optimized. The yield of the target substance was increased, upon the activation in the strain of the tricarboxylic acid cycle variant mediated by the action of heterologous 2-ketoglutarate decarboxylase, due to the intensification of the anaplerotic formation of oxaloacetic acid. Inactivation of the nonspecific thioesterase YciA in the strain did not considerably change the biosynthetic characteristics of the producer. The enhancement of the expression of native phosphoenolpyruvate carboxylase led to an increase in the yield of the target compound by the recombinant synthesizing succinic acid via the reactions of the native tricarboxylic acid cycle from 25 to 42%, and from 67 to 75% upon the induced expression of Mycobacterium tuberculosis 2-ketoglutarate decarboxylase. The expression of the Bacillus subtilis pyruvate carboxylase gene in the strain resulted in an increase in the yield of succinic acid up to 84%. While functioning in whole-cell biocatalyst mode, the engineered strain SUC1.0 P_L-pycA (pMW119-kgd) demonstrated a substrate-to-target product conversion ratio reaching 93%, approaching the corresponding theoretical maximum.

This review is devoted to the analysis of the main mechanisms of the formation of IgE-producing cells in the body and a brief review of the main, most striking candidate agents for use in innovative methods of therapy for IgE-dependent pathologies. Data are presented according to which the role of IgE⁺ plasma cells and various subpopulations of memory B-lymphocytes in the formation and persistence of the state of sensitization to a harmless allergen differs depending on the model system used or the clinical case under study. Therefore, drugs that target signaling pathways involved in the regulation of both plasma cells and memory B-lymphocytes are especially promising in the treatment of allergic diseases. The authors conclude that the components of the cellular response to oxidative stress and related genotoxic stress and ER stress are the most promising as such targets, since (a) all of them directly or indirectly affect the processes that regulate both of these subpopulations; (b) are involved in the process of formation and maintenance of local allergic inflammation. The review presents data pointing to the particular promise of using nanoparticles of noble metals and complexes of rare earth metals of lanthanides in this regard, due to their ability to induce long-term effects in small doses due to changes in the properties of innate immunity cells and long-term accumulation in the body.

This review analyzes current information about the anaerobic type of respiration using a synthetic methacrylate compound as an electron acceptor. Both the methacrylate redox systems themselves and the anaerobic bacteria in whose cells they are found are considered. These complexes consist of flavin-containing reductase and multiheme cytochrome c₃ variants. The genes of the components of the methacrylate redox systems of different microorganisms are homologous and are organized into one operon. Methacrylate-reducing activity is determined in the periplasm. The only known bacterial acrylate reductase that reduces the natural compound differs from methacrylate redox systems. The physiological role, origin, and research perspectives for this unique enzyme system are discussed.

Abstract

A delivery system for vectors for molecular cloning into bacterial cells of the genus Bacillus has been developed. A specific feature of the developed system is the use of the pBS72 plasmid, which provides the conjugative transfer of the conditionally lethal pKS1mob vector obtained into the cells of the studied bacteria. The ability of vector pKS1mob to be replicated in Escherichia coli and B. subtilis cells at a low temperature (30°C) and the presence of two polylinkers around the kanamycin resistance gene makes it possible to clone target gene fragments into its composition using traditional genetic engineering approaches. Inactivation of the rok gene in the pBS72 plasmid made it possible to transform the strain containing it with the constructed vector pKS1mob with high efficiency. Crossing the B. subtilis 168 donor strain, containing the conjugative pBS72 and pKS1mob mobilizable plasmids, with a recipient strain of the genus Bacillus made it possible to introduce the pKS1mob plasmid into it. The possibility of using the created system for inactivation of the codY gene of Bacillus licheniformis was shown.

Abstract

The influence of thermodynamic and kinetic conditions on the interaction of polyclonal antibodies to penicillins with the antibiotics of the penicillin group was studied in the system of a direct enzyme-linked immunosorbent assay (ELISA). Minimal differences in the cross reactions of the polyclonal antibodies with different penicillins were observed when ELISA was carried out at 4°C for 1 h. An increase in temperature and duration of the assay led to an increase in the reactivity of antibodies only to amoxicillin and significantly enhanced differences among the sensitivities of determination of individual penicillins. Under the chosen assay conditions, the following antibody cross-reactivities were obtained: penicillin G, 90%; ampicillin, 100%; and amoxicillin, 110%. The analytical sensitivity was 0.03 ng/mL for ampicillin, and the limit of ampicillin quantification in milk was 0.4 μg/L. The developed group-specific ELISA was used for the determination in milk of seven penicillins that are regulatorily controlled in foods and raw materials of animal origin: penicillin G, ampicillin, amoxicillin, cloxacillin, oxacillin, dicloxacillin and nafcillin.