Optimization of nitrilase production from Alcaligenes faecalis MTCC 10757 (IICT-A3): effect of inducers on substrate specificity

Microbial nitrilases are biocatalysts of interest and the enzyme produced using various inducers exhibits altered substrate specificity, which is of great interest in bioprocess development. The aim of the present study is to investigate the nitrilase-producing Alcaligenes faecalis MTCC 10757 (IICT-A3) for its ability to transform various nitriles in the presence of different inducers after optimization of various parameters for maximum enzyme production and activity. The production of A. faecalis MTCC 10757 (IICT-A3) nitrilase was optimum with glucose (1.0%), acrylonitrile (0.1%) at pH 7.0. The nitrilase activity of A. faecalis MTCC 10757 (IICT-A3) was optimum at 35 °C, pH 8.0 and the enzyme was stable up to 6 h at 50 °C. The nitrilase enzyme produced using different inducers was investigated for substrate specificity. The enzyme hydrolyzed aliphatic, heterocyclic and aromatic nitriles with different substitutions. Acrylonitrile was the most preferred substrate (~40 U) as well as inducer. Benzonitrile was hydrolyzed with almost twofold higher relative activity than acrylonitrile when it was used as an inducer. The versatile nitrilase-producing A. faecalis MTCC 10757 (IICT-A3) exhibits efficient conversion of both aliphatic and aromatic nitriles. The aromatic nitriles, which show not much or no affinity towards nitrilase from A. faecalis, are hydrolyzed effectively with this nitrilase-producing organism. Studies are in progress to exploit this organism for synthesis of industrially important compounds.     

The Effect of Different Levels of Organic and Inorganic Chromium Supplementation on Production Performance, Carcass Traits and Some Blood Parameters of Broiler Chicken Under Heat Stress Condition

A total of 250 broilers in a completely randomized design selected to evaluate the effect of different levels of chromium (Cr) supplementation on performance, carcass traits and some blood parameters of heat-stressed broiler chicks. All birds were kept under heat stress temperature (33?±?3°C) and divided into five treatments groups. Each treatment consisted of five pens with 10 birds in each pen. The basal diets were supplemented with 0?ppb (control), 800?ppb Cr-L-Met (T(1)), 1,200?ppb Cr-L-Met (T(2)) or 800?ppb CrCl(3) (T(3)), and 1,200?ppb CrCl(3) (T(4)). The feed intake and body mass were measured at 10, 21, and 42?days of age. Blood samples were collected from two birds in each replicates to determine biological and hematological values at 28 and 42?days of age. There were no significant difference in mass gain and feed conversion of broilers that received Cr supplementations compared with controls. The serum glucose concentration decreased in broilers received organic chromium methionine supplements compared with other treatments groups. Slight but not significant increases were observed in serum high-density lipoprotein (HDL) concentration of treated groups than controls while the mean serum HDL concentration was significantly higher in T(2) group compared with control group. Serum low-density lipoprotein level decreased in broiler received organic Cr supplements (p?相似文献   

Dietary nutraceuticals as backbone for bone health

Bone loss or osteoporosis, is a slow-progressing disease that results from dysregulation of pro-inflammatory cytokines. The FDA has approved number of drugs for bone loss prevention, nonetheless all are expensive and have multiple side effects. The nutraceuticals identified from dietary agents such as butein, cardamonin, coronarin D curcumin, diosgenin, embelin, gambogic acid, genistein, plumbagin, quercetin, reseveratrol, zerumbone and more, can modulate cell signaling pathways and reverse/slow down osteoporosis. Most of these nutraceuticals are inexpensive; show no side effect while still possessing anti-inflammatory properties. This review provides various mechanisms of osteoporosis and how nutraceuticals can potentially prevent the bone loss.     

Global change‐driven effects on dissolved organic matter composition: Implications for food webs of northern lakes

Northern ecosystems are experiencing some of the most dramatic impacts of global change on Earth. Rising temperatures, hydrological intensification, changes in atmospheric acid deposition and associated acidification recovery, and changes in vegetative cover are resulting in fundamental changes in terrestrial–aquatic biogeochemical linkages. The effects of global change are readily observed in alterations in the supply of dissolved organic matter (DOM)—the messenger between terrestrial and lake ecosystems—with potentially profound effects on the structure and function of lakes. Northern terrestrial ecosystems contain substantial stores of organic matter and filter or funnel DOM, affecting the timing and magnitude of DOM delivery to surface waters. This terrestrial DOM is processed in streams, rivers, and lakes, ultimately shifting its composition, stoichiometry, and bioavailability. Here, we explore the potential consequences of these global change‐driven effects for lake food webs at northern latitudes. Notably, we provide evidence that increased allochthonous DOM supply to lakes is overwhelming increased autochthonous DOM supply that potentially results from earlier ice‐out and a longer growing season. Furthermore, we assess the potential implications of this shift for the nutritional quality of autotrophs in terms of their stoichiometry, fatty acid composition, toxin production, and methylmercury concentration, and therefore, contaminant transfer through the food web. We conclude that global change in northern regions leads not only to reduced primary productivity but also to nutritionally poorer lake food webs, with discernible consequences for the trophic web to fish and humans.     

The Yin and Yang of carbon nanomaterials in atherosclerosis

With unique characteristics such as high surface area, capacity of various functionalization, low weight, high conductivity, thermal and chemical stability, and free radical scavenging, carbon nanomaterials (CNMs) such as carbon nanotubes (CNTs), fullerene, graphene (oxide), carbon nanohorns (CNHs), and their derivatives have increasingly been utilized in nanomedicine and biomedicine. On the one hand, owing to ever-increasing applications of CNMs in technological and industrial fields as well as presence of combustion-derived CNMs in the ambient air, the skepticism has risen over the adverse effects of CNMs on human being. The influences of CNMs on cardiovascular system and cardiovascular diseases (CVDs) such as atherosclerosis, of which consequences are ischemic heart disease and ischemic stroke, as the main causes of death, is of paramount importance. In this regard, several studies have been devoted to specify the biomedical applications and cardiovascular toxicity of CNMs. Therefore, the aim of this review is to specify the roles and applications of various CNMs in atherosclerosis, and also identify the key role playing parameters in cardiovascular toxicity of CNMs so as to be a clue for prospective deployment of CNMs.     

Olive (Olea europaea L.) freezing tolerance related to antioxidant enzymes activity during cold acclimation and non acclimation

The changes in the antioxidant enzymes activity, total protein and proline content and their correlations with freezing tolerance (FT) (expressed as LT₅₀) were investigated at 11 different olive cultivars at cold-acclimation (CA, in February) and non-acclimation (NA, in August) stages. Leaf samples were collected from each cultivar and were divided into two groups. The first group was immediately frozen in liquid nitrogen for further biochemical analysis. The second ones was subjected to different freezing temperatures (?5, ?10, ?15 and ?20 °C) for 10 h, in order to determine their FT. The unfrozen control samples were kept at 4 °C. The results showed that Fishomi, Mission and Shengeh were the most freezing tolerant among other cultivars. In contrast, Zard, Manzanilla and Amigdalolia were the most sensitive ones. The cold acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), polyphenol oxidase (PPO) and total protein content. However, proline content and phenylalanine ammonia-lyase (PAL) activity did not change or even decreased slightly at CA stage, compare to those samples at NA stage. It was found that LT₅₀ to be closely correlated to POD, CAT, and PPO activity at CA and NA stages. Overall, higher leaf POD, CAT, and PPO activity could be used as important selection criteria in screening tolerant olive cultivars for cold zone climatic.     

Dissolved oxygen concentration regulates human hepatic organoid formation from pluripotent stem cells in a fully controlled bioreactor

Developing technologies for scalable production of human organoids has gained increased attention for “organoid medicine” and drug discovery. We developed a scalable and integrated differentiation process for generation of hepatic organoid from human pluripotent stem cells (hPSCs) in a fully controlled stirred tank bioreactor with 150 ml working volume by application of physiological oxygen concentrations in different liver tissue zones. We found that the 20–40% dissolved oxygen concentration [DO] (corresponded to 30–60 mmHg pO₂ within the liver tissue) significantly influences the process outcome via regulating the differentiation fate of hPSC aggregates by enhancing mesoderm induction. Regulation of the [DO] at 30% DO resulted in efficient generation of human fetal-like hepatic organoids that had a uniform size distribution and were comprised of red blood cells and functional hepatocytes, which exhibited improved liver-specific marker gene expressions, key liver metabolic functions, and, more important, higher inducible cytochrome P450 activity compared to the other trials. These hepatic organoids were successfully engrafted in an acute liver injury mouse model and produced albumin after implantation. These results demonstrated the significant impact of the dissolved oxygen concentration on hPSC hepatic differentiation fate and differentiation efficacy that should be considered ascritical translational aspect of established scalable liver organoid generation protocols for potential clinical and drug discovery applications.     

Expression of Enterocin-P in HEK Platform: Evaluation of Its Cytotoxic Effects on Cancer Cell Lines and Its Potency to Interact with Cell-Surface Glycosaminoglycan by Molecular Modeling

International Journal of Peptide Research and Therapeutics - Cancer remains one of the leading causes of death worldwide. Introduction of natural compounds with anticancer properties can be an...     

Resveratrol potentially increased the tumoricidal effect of doxorubicin on SKOV3 cancer stem cells in vitro

Ovarian cancer is associated with a high percentage of recurrence of tumor and resistance to chemotherapy. Cancer stem cells (CSCs) form a rare population with a significant capacity to begin and expand malignant diseases. Eliminating the drug resistance of CSCs by factors that have fewer side effects to the patient is vital. To investigate the effect of resveratrol (RES) and doxorubicin (DOX) on drug resistance and apoptosis of CSCs; at the first, isolation of CSCs from SKOV3 ovarian carcinoma cells and their dosage adjustment (IC₅₀) with RES and DOX was performed. Then, isolated CSCs were treated with RES and DOX IC ₅₀ of 55 and 250 nM, respectively. Subsequently, their effects on drug resistance and cell death were evaluated using real-time polymerase chain reaction, rhodamine 123 uptakes. The results of the present study demonstrated that treatment of SKOV3 with 55 μM of RES and 250 nM of DOX simultaneously increased cell viability in CSCs to DOX after 24 and 48 hours by increasing the expression of Bcl-2-associated X protein (BAX) and caspase-3 genes, and decreased the expression and function of multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 1 (MRP1) genes indicated by intracellular the rhodamine 123 content. Treatment of RES could increase the activity of DOX cell viability in CSCs originated from SKOV3 ovarian carcinoma and decrease drug resistance capacity to DOX.     

A novel copper (II) complex activated both extrinsic and intrinsic apoptotic pathways in liver cancerous cells

Recent advances have put fundamental focus on the application of copper (II) (Cu [II]) complexes as agents for fighting against cancer. To determine whether [Cu(L)(2imi)] complex as a novel Cu complex can induce apoptosis in HepG2 as cancerous cells and L929 as normal cells via extrinsic or intrinsic apoptotic pathways, both cell lines were treated for 24 and 48 hours at IC₅₀ concentrations of [Cu(L)(2imi)] complex. Then, the expression of some apoptosis-related genes including p53, caspase-8, bcl-2, and bax were assayed by real-time polymerase chain reaction. The [Cu(L)(2imi)] complex seems to inhibit the expression of bcl-2 in complex-treated HepG2 cancerous cells following the 24- and 48-hour treatment. The complex upregulated the p53, bax, and caspase-8 genes, therefore treatment of HepG2 cancerous cells with [Cu(L)(2imi)] complex induces programmed cell death via the upregulation of relative bax/bcl-2 ratio. Finally, this copper complex triggered apoptosis in HepG2 cells via both intrinsic and extrinsic pathway, whereas treatment of normal L929 cells with this complex induce apoptosis only via intrinsic pathway with the upregulation of relative bax/bcl-2 ratio and does not affect the expression level of caspase-8 gene and does not trigger the extrinsic pathway. Finally, these results obtained from present study confirm the role of a novel Cu complex on the induction of apoptosis process in HepG2 and L929 cells by overexpression of bax, inhibition of bcl-2 and increase of the relative bax/bcl-2 ratio. These results support that the [Cu(L)(2imi)] complex is able to induce apoptosis in cancerous cells, therefore, it has a potential for development as a novel anticancer drug.