Cell immobilization of Streptomyces griseobrunneus by microcrystalline cellulose for production of cyclodextrin glucanotransferase enzyme

The cyclodextrin glucanotransferase are extracellular enzymes that can hydrolysis starch as a substrate to cyclodextrin. Encapsulation and immobilization technique of microbial cells within the polymeric network have widespread applications in the production of enzyme. Bacterial cells were isolated from soil by serial dilution method. The molecular identity was established using 16S rDNA sequence analysis, and the identified strain was immobilized in the synthesized composites. Physicochemical characteristics of the synthesized composites were determined by using field emission scanning electron microscopy, Malvern Zetasizer Nano ZS and FT-IR analyses. Enzyme activity was measured by phenolphthalein assay. Streptomyces griseobrunneus was identified according to the 16S rDNA sequence. FT-IR analyses indicated that there was an interaction between all of the elements. Scanning electron microscopy analysis showed a cross-section of composites without cells and cells attached to composites. Enzyme activity was 1109, 948 and 606 U/ml in alginate/chitosan/microcrystalline cellulose (MCC) sheets, agar/gelatin/MCC beads and free cells, respectively. It could be concluded that the polymeric immobilization was effective in improving enzyme production because of its excellent properties such as guarding the bacterial cells against inhibitors and toxins. © 2021 The Author(s). This open access article is distributed under a Creative Commons Attribution (CC-BY) 4.0 license

Immobilization of Clostridium perfringens type D in calcium alginate beads: toxin production mimics free cell culture

Background and Objectives: Cell-immobilization is used to maintain microbial culture to produce metabolites in repeat-ed-batch or continuous fermentations, thereby reducing the time and resources spent on delivering mass production of microbe. The technique also enables shortening of the detoxification phase and the amount of formaldehyde required due to low incidence of viable bacteria in the extract. Materials and Methods: A solution of sodium alginate containing Clostridium perfringens cells was dropped into stirring CaCl solution via a sterile syringe needle. Optimizations resulted in reasonably uniform beads containing C. perfringens. 2 Beads were externally stabilized by poly L-lysine, followed by immersion in a solution of Na-alginate to coat them with a new layer of alginate forming an alginate-PLL-alginate cortex. Results: This study proved successful in immobilizing C. perfringens cells inside uniform alginate microspheres. Cell load-ing and cell propagation inside the beads were measured. The cell loaded beads were cultivable in liquid media producing 550 minimum lethal doses per milliliter (MLD/ml) in a 72 h. Conclusion: The research paved the way for further investigations to optimize and establish an efficient bacterial encapsulation method. Thus, it seems possible to produce toxins from beads engulfing C. perfringens on larger scales via repeat-ed-batch or continuous fermentation processes. © 2022 The Authors. Published by Tehran University of Medical Sciences

Bioactive anti-oxidative polycaprolactone/gelatin electrospun nanofibers containing selenium nanoparticles/vitamin E for wound dressing applications

In this study, polycaprolactone/gelatin (PCL/GEL) electrospun nanofibers containing biogenic selenium nanoparticles (Se NPs) and Se NPs/vitamin E (VE) with average diameters of 397.8 nm and 279.5 nm, respectively (as determined by SEM inspection) were prepared and their effect on wound healing was evaluated using in-vivo studies. The energy dispersive X-ray (EDX) mapping, TEM micrograph, and FTIR spectra of the prepared nanofibers strongly demonstrated well entrapment of Se NPs and VE into scaffolds. An amount of 57 Se NPs and 43 VE were gradually released from PCL/GEL/Se NPs/VE scaffold after 4 days immersion in PBS solution (pH 7.4). The both PCL/GEL/Se NPs and PCL/GEL/Se NPs/VE scaffolds supported 3T3 cell proliferation and attachment as confirmed by MTT assay and SEM imaging. Complete re-epithelialization, low level of edema and inflammatory cells in coordination with high level of oriented collagens demonstrated the wound healing activity of PCL/GEL/Se NPs/VE. Besides, significant antioxidant efficacy of PCL/GEL/Se NPs and PCL/GEL/Se NPs/VE scaffolds was demonstrated according to GSH and MDA assays. To sum up, the prepared PCL/GEL/Se NPs/VE scaffold in the present study represented suitable healing effect on animal model which candidate it for further studies. © The Author(s) 2021

Antileishmanial effects and drugability characteristics of a heterocyclic copper complex: An in silico, in vitro and molecular study

Leishmaniasis caused by the protozoan Leishmania presents a severe illness, principally in tropical and subtropical areas. Antileishmanial metal complexes, like Glucantime (R) with proven activity, are routinely studied to probe their potency. We investigated the effects of a Cu (II) homoleptic complex coordinated by two dimethylbipyridine ligands against Leishmania major stages in silico and in vitro. The affinity of this heterocyclic Cu (II) complex (CuDMBP) towards a parasitic metacaspase was studied by molecular docking. Key pharmacokinetic and pharmacodynamic properties of the complex were predicted using three web-based tools. CuDMBP was tested for in vitro antileishmanial activities using MTT assay, model murine macrophages, flow cytometry, and quantitative real-time polymerase chain reaction (qPCR). Molecular docking confirmed the tendency between the target macromolecule and the complex. ADMET evaluations highlighted CuDMBP's key pharmacological features, including P-glycoprotein-associated GI absorption and lack of trans-BBB permeability. MTT showed significant inhibitory effects against promastigotes. CuDMBP significantly increased the level of cellular IL-12 expression (p 0.05). It decreased the expression of IL-10 significantly (p < 0.05). Findings demonstrated that CuDMBP deserves to be introduced as a leishmanicidal candidate provided further studies are carried out

Tris-chelated complexes of nickel(II) with bipyridine derivatives: DNA binding and cleavage, BSA binding, molecular docking, and cytotoxicity

<p>Two nickel(II) complexes with substituted bipyridine ligand of the type [Ni(NN)₃](ClO₄)₂, where NN is 4,4′-dimethyl-2,2′-bipyridine (dimethylbpy) (<b>1</b>) and 4,4′-dimethoxy-2,2′-bipyridine (dimethoxybpy) (<b>2</b>), have been synthesized, characterized, and their interaction with DNA and bovine serum albumin (BSA) studied by different physical methods. X-ray crystal structure of <b>1</b> shows a six-coordinate complex in a distorted octahedral geometry. DNA-binding studies of <b>1</b> and <b>2</b> reveal that both complexes sit in DNA groove and then interact with neighboring nucleotides differently; <b>2</b> undergoes a partial intercalation. This is supported by molecular-docking studies, where hydrophobic interactions are apparent between <b>1</b> and DNA as compared to hydrogen bonding, hydrophobic, and <i>π–π</i> interactions between <b>2</b> and DNA minor groove. Moreover, the two complexes exhibit oxidative cleavage of supercoiled plasmid DNA in the presence of hydrogen peroxide as an activator in the order of <b>1 </b>><b> 2</b>. In terms of interaction with BSA, the results of spectroscopic methods and molecular docking show that <b>1</b> binds with BSA only via hydrophobic contacts while <b>2</b> interacts through hydrophobic and hydrogen bonding. It has been extensively demonstrated that the nature of the methyl- and methoxy-groups in ligands is a strong determinant of the bioactivity of nickel(II) complexes. This may justify the above differences in biomolecular interactions. In addition, the <i>in vitro</i> cytotoxicity of the complexes on human carcinoma cells lines (MCF-7, HT-29, and U-87) has been examined by MTT assay. According to our observations, <b>1</b> and <b>2</b> display cytotoxicity activity against selected cell lines.</p> <p></p> <p>Communicated by Ramaswamy H. Sarma</p