Chitin and chitosan biopolymer production from the Iranian medicinal fungus Ganoderma lucidum: Optimization and characterization

Abstract

Chitin and chitosan with unique properties and numerous applications can be produced from fungus. The production of chitin and chitosan from the mycelia of an Iranian Ganoderma lucidum was studied to improve cell growth and chitin productivity. Inoculum size and initial pH as two effective variables on the growth of G. lucidum and chitin production were optimized using response surface method (RSM) by central composite design (CCD). The results verified the significant effect of these two variables on the cell growth and chitin production. In optimum conditions, including pH?=?5.7 and inoculum size of 7.4%, the cell dry weight was 5.91?g/L and the amount of chitin production was 1.08?g/L with the productivity of 0.083?g/(L day). The produced chitin and chitosan were characterized using XRD and FTIR. Moreover, the antibacterial activity of the produced chitosan was investigated and compared with the commercial chitosan. The results showed that the produced chitin and chitosan had suitable quality and the Iranian G. lucidum would be a great source for safe and high-quality chitin and chitosan production.     

Synthesis of novel Gn-RH analogues using Ugi-4MCR

An efficient method for the synthesis of some Gn-RH analogues based on Ugi reaction has been developed. Four-component reaction of N- and C-terminus peptides, aromatic aldehydes and isocyanides affords novel Gn-RH analogues derived from triptorelin and gonadorelin. All of the products were purified using preparative HPLC and the structures were assigned according to MALDI-mass spectrometry data.     

Graphene oxide/silver nanohybrid: Optimization,antibacterial activity and its impregnation on bacterial cellulose as a potential wound dressing based on GO‐Ag nanocomposite‐coated BC

Recently, bacterial cellulose (BC) based wound dressing have raised significant interests in medical fields. However, to our best knowledge, it is apparent that the BC itself has no antibacterial activity. In this study, we optimized graphene oxide‐silver (GO‐Ag) nanohybrid synthesis using Response Surface Methodology and impregnate it to BC and carefully investigate their antibacterial activities against both the Gram‐negative bacteria Escherichia coli and the Gram‐positive bacteria Staphylococcus aureus. We discover that, compared to silver nanoparticles, GO‐Ag nanohybrid with an optimal GO suspension's pH and ratio is much more effective and shows synergistically enhanced, strong antibacterial activities at rather low dose. The GO‐Ag nanohybrid is more toxic to E. coli than that to S. aureus. The antibacterial and mechanical properties of BC/GO‐Ag composite are further investigated.     

Label-Free Detection of Digoxin Using Localized Surface Plasmon Resonance-Based Nanobiosensor

Plasmonics - The scientific community finds gold nanoparticles particularly interesting due to their great applications, especially in SPR-based analysis. So far, no contributions have been made on...     

Evaluating the Potential of an Antibody Against Recombinant OmpW Antigen in Detection of Vibrio cholerae by Surface Plasmon Resonance (SPR) Biosensor

Surface plasmon resonance (SPR), a highly sensitive and label-free optical biosensing technique, is a powerful tool for studying biomolecular interactions. An immunosensor for rapid, sensitive, and selective detection of Vibrio cholerae on the basis of SPR is reported. Recombinant OmpW antigen (a bacterial outer-membrane protein) of V. cholerae was expressed and purified and raising of polyclonal rabbit anti-OmpW was done. Antibodies were immobilized on a sensor surface and interactions between OmpW protein and the whole cell of V. cholerae with immobilized antibodies were studied in different experiments. The aim of this study was to evaluate the potential of anti-OmpW in detection of V. cholerae by developing an immunosensor based on SPR. The results showed high affinity interaction between OmpW and anti-OmpW (K _D = 2.4 ± 0.07 × 10⁻⁹ M) and SPR signals had a linear relationship with the number of V. cholerae ranging from 1 × 10² to 1 × 10⁷ cells/mL with limit of detection of 50 cells/mL. The specificity of the developed immunoassay was examined using some non-V. cholerae bacteria which did not produce any significant responses. This method is rapid, sensitive, and specific to target V. cholerae with a total analysis time of less than 60 min.

     

Novel DNA methylation marker discovery by assumption‐free genome‐wide association analysis of cognitive function in twins

Privileged by rapid increase in available epigenomic data, epigenome‐wide association studies (EWAS) are to make a profound contribution to understand the molecular mechanism of DNA methylation in cognitive aging. Current statistical methods used in EWAS are dominated by models based on multiple assumptions, for example, linear relationship between molecular profiles and phenotype, normal distribution for the methylation data and phenotype. In this study, we applied an assumption‐free method, the generalized correlation coefficient (GCC), and compare it to linear models, namely the linear mixed model and kinship model. We use DNA methylation associated with a cognitive score in 400 and 206 twins as discovery and replication samples respectively. DNA methylation associated with cognitive function using GCC, linear mixed model, and kinship model, identified 65 CpGs (p < 1e‐04) from discovery sample displaying both nonlinear and linear correlations. Replication analysis successfully replicated 9 of these top CpGs. When combining results of GCC and linear models to cover diverse patterns of relationships, we identified genes like KLHDC4, PAPSS2, and MRPS18B as well as pathways including focal adhesion, axon guidance, and some neurological signaling. Genomic region‐based analysis found 15 methylated regions harboring 11 genes, with three verified in gene expression analysis, also the 11 genes were related to top functional clusters including neurohypophyseal hormone and maternal aggressive behaviors. The GCC approach detects valuable methylation sites missed by traditional linear models. A combination of methylation markers from GCC and linear models enriched biological pathways sensible in neurological function that could implicate cognitive performance and cognitive aging.     

Betanin alleviates oxidative stress through the Nrf2 signaling pathway in the liver of STZ-induced diabetic rats

Background

Continuing hyperglycemia causes and exacerbate oxidative stress. Betanin as the principal pigment of red beet root has antioxidant, anti-inflammatory, and anti-diabetic properties. The purpose of this study was to investigate the potency of betanin on antioxidant defense in STZ-induced diabetic rats’ livers.

Methods

STZ at a single dose of 60 mg/kg body weight was intraperitoneally injected and betanin (10, 20, and 40 mg/kg/day) was administered orally for 28 days. Malondialdehyde (MDA), total antioxidant capacity (TAC), protein carbonyl (PC) levels, and the enzyme activity of superoxide dismutase (SOD), catalases and glutathione peroxidases (GPx) were evaluated in the liver. Furthermore, gene expression of Nrf2 and mentioned antioxidant enzymes were measured by Real-time PCR.

Results

Betanin (10 and 20 mg/kg) significantly reduced PC levels and increased antioxidant enzyme activity in diabetic rats compared to the control diabetic group (P?<?0.01). In comparison to the diabetic control group, all studied genes expression in diabetic rats were increased significantly with betanin at doses of 10 and 20 mg/kg (P?<?0.02). The increase in gene expression at 20 mg/kg of betanin was significantly stronger than others (P?<?0.015) except for the catalase (P?=?0.201), that was almost the same. Moreover, treatment of diabetic rats with 20 mg/kg of betanin could significantly increase TAC levels (P?<?0.05) and decrease MDA levels (P?<?0.001) compared to diabetic control group.

Conclusions

Betanin could increase the antioxidant capacity of liver tissue associated with the Nrf2-mediated pathway in a dose-dependent manner.

     

Association between vitamin D receptor gene polymorphisms and type 1 diabetes mellitus in Iranian population

Type 1 diabetes mellitus (T1DM) is one of the T-cell mediated autoimmune diseases and vitamin D suppresses activation of T-cell and has immunomodulatory effects. In this study the association between four vitamin D receptor (VDR) gene polymorphisms, at positions FokI, BsmI, ApaI and TaqI, and susceptibility to T1DM was investigated. We assessed 87 Iranian patients with T1DM and one hundred healthy controls with no history of diabetes or other autoimmune diseases. Our results demonstrated that genotypes frequency of the TaqI VDR polymorphism differed significantly between T1DM patients and controls, TT genotype and T allele was more frequent in healthy controls compared with TIDM patients (P = 0.003; OR = 0.51, 95% CI = 0.31–0.84). Therefore, allele t is the risk-allele for developing TIDM in this study. No significant association was observed between others VDR SNPs and disease susceptibility. In conclusion, our case-control study indicated that the VDR TaqI polymorphism is associated with TIDM in Iranian population.     

Inherent anti-HIV activity of biocompatible anionic citrate-PEG-citrate dendrimer

Molecular Biology Reports - The development of new combinations to empower better protection against HIV infection is particularly important. Anionic polymers can block HIV infection. In the...