background: we aimed at evaluating the toxicity effects of low (subtoxic) concentrations of silver nanoparticles (agnp, 5-10 nm) in human hepatoblastoma (hepg2) cell line after and during a period of about one month. methods: xtt and mtt assays were used to draw a dose-response curve ic50 (half maximal inhibitory concentration) value of the agnp on hepg2 cells was calculated to be 2.75-3.0 mg/l...

background: little in known regarding the clinical relevance of sirt1 in multiple sclerosis (ms).   here, we aimed to evaluate mrna expression, protein level and enzyme activity of sirt1 in peripheral blood mononuclear cells (pbmcs) isolated from relapsing –remitting ms patients (rrms) and healthy controls. materials and methods: twenty patients with rr-ms and twenty two age- and sex-matched he...

effects of yeast extract (ye) (0, 0.05, 0.1, 0.2, 0.5 and 1%) were investigated on rosmarinic acid (ra) accumulation and tyrosine aminotransferase (tat) gene expression in melissa officinalis seedlings at different time intervals (4 and 17 hours). based on the results, only ye concentrations of 0.05%, 0.1%, and 0.2%, for the 17-hour treatment, significantly stimulated ra biosynthesis pathway. a...

background: collagen, the most abundant protein in the human body, and as an extracellular matrix protein, has an important role in the fiber formation. this feature of the collagen renders  establishment of the structural skeleton in tissues. regarding specific features associated with the collagen, such as, formation of the porous structure, permeability and hydrophilicity, it can also be use...

six strain of trichoderma (t. viride, t. harzianum, t. reesei, t. longibrachiatum, t. koningii, t. virens) were isolated and used for extracellular enzyme production. species of trichoderma are collected from the surrounding soil of suger beet root fields in east iran, and held in vitro cultured pda. tcm and tfm are used for the growth of spores and induceing the production of cellulase. finall...

this study evaluated the effect of the intermittent light program on serum and brain melatonin concentrations, antioxidant enzyme activities, and homocysteine concentration in broiler chickens. a total of 60 one-day-old broiler chickens (cobb 500) were distributed in three light-proof controlled rooms (20 chicks per room). all birds were reared in continuous light until 3 days of age. then, chi...

objective: investigations were carried out to isolate bacteria from saline-alkali soils and determined optimized alkaline protease activity and stability produced by a wild strain of bacillus sp. in submerged fermentation (smf). methods: optimum temperature for enzyme activity in the crude extract was 40 ◦c at a ph between 8.0 and 9.0. the studies on ph stability showed that the enzyme was stab...

the objective of this study was to investigate aspartate-amino-transferase (ast), γ-glutamyl-transferase(ggt), alkaline phosphatase (alp), lactate-dehydrogenase (ldh) and acid phosphatase (acp) activities andsemen parameters (volume, ph, concentration, total sperm number (tsn), progressive motility, dead sperm,total morphological defect (tmd) and hypo-osmotic swelling test (host)) in seminal pl...