Nowadays, preparing biodegradable films based on hydrocolloids has become thoroughly crucial in food packaging. Also, to enhance some of the aspects of these films, adding oil to the formulation of ...the films has been considered as a valid method. In this study, a variety of films based on two biopolymers (fenugreek galactomannan and xanthan gum) in the presence or absence of grape seed oil were produced and the various aspects of the obtained films were comprehensively investigated. The obtained data demonstrated that preparing composite films based on two hydrocolloids improved the aspects including film thickness, water vapor permeability (WVP), oxygen permeability (OP), mechanical and thermal properties more than films based on only one hydrocolloid. This improvement was mostly related to the good and acceptable interaction between two biopolymers. The X‐ray diffraction (XRD) patterns indicated that all films had an amorphous or non‐crystalline structure. Also, the scanning electron microscope images demonstrated that films based on fenugreek galactomannan and composite films based on two hydrocolloids. The value of film thickness and strain at break (SAB) increased by adding oil to the formulation. Contrarily, the moisture content and absorption, WVP, OP, opacity, and ultimate tensile strength (UTS) values of the films decreased by adding oil.
Arsenic oxyanions are toxic chemicals that impose a high risk to humans and other living organisms in the environment. The present study investigated indigenous heterotrophic bacteria in the tailings ...dam effluent (TDE) of a gold mining factory. Thirty-seven arsenic resistant bacteria were cultured on Reasoner's 2A agar supplemented with arsenic salts through filtration. One strain encoded as PMS5 with the highest resistance to 140-mM sodium arsenite and 600-mM sodium arsenate in tryptic soy broth was selected for further investigations. According to phenotypic examinations and 16S rDNA sequence analysis, PMS5 belonged to the genus Alishewanella and was sensitive to most of the examined antibiotics. The biosorption and bioaccumulation abilities of arsenic salts were observed in this isolate based on Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) and biosorption and bioaccumulation data. PMS5 was also found to cause the volatilization and biotransformation of arsenic oxyanions through their oxidation and reduction. Moreover, the contribution of PMS5 to arsenic (3+, 5+) bioprocessing under oligotrophic conditions was confirmed in fixed-bed reactors fed with the TDE of the gold factory (R1) and synthetic water containing As5+ (R2). According to biofilm assays such as biofilm staining, cell count, detachment assay and SEM, the arsenic significantly reduced the biofilm density of the examined reactors compared to that of the control (R3). Arsenate reduction and arsenite oxidation under bioreactor conditions were respectively obtained as 75.5–94.7% and 8%. Furthermore, negligible arsenic volatilization (1.2 ppb) was detected.
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•Highly arsenic-resistant Alishewanella agri strain PMS5 was isolated from a gold mine factory.•The bacterium had a strong ability to resist As5+ and appropriately reduced it.•Remarkable biosorption was measured and small amounts of the arsenic volatilization observed.•The bacterium is a noteworthy candidate for As3+ and As5+ bioremediation from polluted wastewaters.
A new isolate, Kocuria sp. ASB 107 from the Ab-e-Siah mineral radioactive spring (Ramsar, Mazandaran Province, Iran) was characterized on the basis of morphological and biochemical characteristics ...plus 16S rRNA gene sequencing. The isolate is most closely related to Kocuria rosea DSM 20447T (99.7% sequence similarity) and Kocuria polaris DSM 14382T (99.5%). This strain has some resistance to various genotoxic stresses, such as ionizing radiation, ultraviolet (256 nm- UV) and corona discharge. The 90% lethal doses (D10) for gamma-rays and 256 nm-UV are 2 kGy and 400 J m−2, respectively, in definite cell concentration. Moreover, the resistance for a definite energy of corona discharge is 10 s, about 10 times greater than that of Escherichia coli. The growth temperature of the strain ASB 107 is 0–37 °C in TSB (tryptic soy broth). This study is the first report on the psychrotrophic radio-resistant bacteria belonging to the Kocuria genus isolated from Ab-e-Siah spring.
Low grade grape juice concentrate was used as carbon source for xanthan production. Significant factors affecting xanthan concentration, productivity and viscosity were investigated using ...Plackett-Burman Design. Based on the obtained results, carbon and nitrogen concentrations, inoculum size and agitation rate, were assumed as significant factors. Broth culture viscosity and xanthan concentration were optimized using Response Surface Methodology with four independent variables: carbon source (30, 40, 50 g l-1), ammonium sulfate as nitrogen source (0.5, 1.25, 2 g l-1), agitation (150, 200, 250 rpm) and inoculum size (5, 10, 15% v v-1). Optimum level for each factor was obtained by desirability function approach. The average of xanthan gum production and its viscosity under optimized conditions were recorded as 14.35 g l-1 and 1268 cP, respectively. The average yield of production and productivity of xanthan within 72 h under optimized conditions were 35% and 0.19 g l-1 h-1, respectively. The current study showed the potential of low-grade grape juice concentrate as an economic carbon source for xanthan gum production.
Bioremediation of toxic nonmetal and metalloid oxyanions is of great interest. In this study, among 148 bacterial isolates from two types of polluted water, strain STG-83 showed maximum oxyanion ...reduction and resistance ability. Sequencing of the 16S rDNA gene of STG-83 showed that the strain is closely related to
Bacillus pumilus and morphological and biochemical tests confirmed the result. The strain was nitrate negative, but it could reduce half of tellurite in solution containing 1-mM concentration and completely reduced selenite and selenate in solutions containing 1-mM concentrations. Both reduction to elemental form and volatilization occurred in case of all oxyanions tested, according to hydride generation atomic absorption spectroscopy and proton induced X-ray emission analytical methods. The strain was able to tolerate remarkably high concentrations of selenite (640
mM), selenate (320
mM), and tellurite (1250
μM); and tolerance to tellurite increased in presence of selenite and selenate. Biochemical tests and zymogram of extracted culture solutions on gel electrophoresis showed that the strain was nitrate negative and therefore nitrate did not interfere with reduction of other oxyanions. Thus, the strain opens up good opportunities for the bioremediation of polluted waters in natural environment, since nitrate usually inhibits or decelerates reduction of the mentioned toxic oxyanions.
Micro-RNAs (miRNAs) are a class of posttranscriptional regulators that play crucial roles in various biological processes. Emerging evidence suggests a direct link between miRNAs and development of ...several diseases including type 2 diabetes (T2D). In this study, we aimed to investigate the effect of predicted miRNA and target genes on insulin resistance.
This experimental study was conducted on the C2C12 cell line. Using bioinformatics tools miRNA-135 and two respective target genes-insulin receptor (Insr) and vesicle associated membrane protein 2 (Vamp2)were selected as potential factors involved in insulin resistance process. Levels of glucose uptake miRNA expression and respective gene targets were determined after cell transfaction by miR-135.
It was determined that Insr gene expression was significantly down-regulated in miR-135 transfected C2C12 cell line (P≤0.05). Interestingly; these transfected cells have shown a significant difference in glucose uptake incomparision the positive control cells, while it was similar to the insulin resistant cell line (P≤0.05). In contrast, no significant alteration of Vamp2 gene expression was observed.
Our data indicated no change on the Vamp2 expression level after miRNA transfection, while expression level of Insr was reduced and miR-135 expression was contrarily increased leading to poor stimulation of glucose uptake through insulin, and development of insulin resistance phenotype in C2C12 cell line.
Bacterial polyphenol oxidases (PPOs) with a high oxidizing capacity for a wide range of substrates could make their applications in phenolic biotransformation, food processing, cosmetics, and textile ...industry. We have isolated a melanogenic soil bacterium by differential screening of a number of strains which were isolated from the Iranian microflora. The taxonomic characterization of this strain indicates that it belongs to the genus
Bacillus (HR03), and has the ability to produce all types of PPOs; cresolase (EC 1.14.18.1), cathecolase (EC.1.10.3.1), and laccase (EC 1.10.3.2). We studied the tyrosinase activity using
l-tyrosine and
l-dopa as substrates and the laccase activity with specific substrates such as syringaldazine and 2,6-dimethoxyphenol. The optimum pH and temperature, obtained for all types of polyphenol oxidases, were at about pH 5.5 and 55
°C, respectively. Tyrosinase-like enzyme of this strain shows a lag period in its tyrosine hydroxylase activity that could be avoided by the addition of small amounts of
l-dopa and sodium dodecyl sulfate (SDS). In addition, tyrosinase and laccase were activated by SDS below the critical micelle concentration and were inhibited by 1
mM EDTA. We tested the resistance of melanized-cells against UVA, UVC and H
2O
2. Results show that melanin protects strain HR03 against UV lights and the oxidant.
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