cell free extracts of Candida parapsilosis ATCC 7330 for the synthesis of gold nanoparticles

The cell free extracts of Candida parapsilosis ATCC 7330 are more efficient than the whole resting cells of the yeast in the synthesis of directly usable gold nanoparticles as revealed by this systematic study. Cell free extracts yielded gold nanoparticles of hydrodynamic diameter (50-200 nm). In this study, the total protein concentration influences the nanofabrication and not only the reductase enzymes as originally thought. Powder X-ray diffraction studies confirm the crystalline nature of the gold nanoparticles. Fourier Transform Infra Red spectroscopy and thermal gravimetric analysis suggests that the biosynthesized gold nanoparticles are capped by peptides/proteins. Dispersion experiments indicate a stable dispersion of gold nanoparticles in pH 12 solutions which is also confirmed by electron microscopic analysis and validated using a surface plasmon resonance assay. The effectiveness of the dispersed nanoparticles for the reduction of 4-nitrophenol using sodium borohydride as a reductant further confirms the formation of functional gold nanoparticles. It is also reported that gold nanoparticles with mean particle diameter of 27 nm are biosynthesized inside the whole cell by transmission electron microscopy analysis. With optimized reaction conditions, maximum gold bioaccumulation with the 24 h culture age of the yeast with cellular uptake of ~1010 gold atoms at the single cell level is achieved but it is not easy to extract the gold nanoparticles from the whole resting cells.

Endosulfan induced alteration in bacterial protein profile and RNA yield of Klebsiella sp. M3, Achromobacter sp. M6, and Rhodococcus sp. M2

Three bacterial strains identified as Klebsiella sp. M3, Achromobacter sp. M6 and Rhodococcus sp. M2 were isolated by soil enrichment with endosulfan followed by shake flask enrichment technique. They were efficiently degrading endosulfan in the NSM (non sulfur medium) broth. Degradation of endosulfan was faster with the cell free extract of bacterial cells grown in the sulfur deficient medium (NSM) supplemented with endosulfan than that of nutrient rich medium (Luria Bertani). In the cell free extract of NSM supplemented with endosulfan as sole sulfur source, a unique band was visualized on SDS-PAGE but not with magnesium sulfate as the sole sulfur source in NSM and LB with endosulfan. Expression of a unique polypeptide band was speculated to be induced by endosulfan under sulfur starved condition. These unique polypeptide bands were identified as OmpK35 protein, sulfate binding protein and outer membrane porin protein, respectively, in Klebsiella sp. M3, Achromobacter sp. M6 and Rhodococcus sp. M2. Endosulfan showed dose dependent negative effect on total RNA yield of bacterial strains in nutrient rich medium. Absence of plasmid DNA indicated the presence of endosulfan metabolizing gene on genomic DNA.

Expression of pluripotency markers in human granulosa cells after embryonic stem cell extract exposure and epigenetic modification

BACKGROUND

Epigenetic reprogramming of differentiated cells can modify somatic cells into pluripotential state. Pluripotency can be induced in somatic cells by several approches. One of the easy ways to induce pluripotency is the exposure of the somatic cells to the embryonic stem cell (ESC) extract.

OBJECTIVE

The objective of this study was to increase the efficiency of reprogramming of granulosa cell as a differentiated cell into pluripotential state by using epigenetic modifier agents and extract.

MATERIALS AND METHODS

The human granulosa cells were cultured in the medium containing 5-Aza-Deoxycytidine and trichostatin A. Then, the cells were exposed to mouse ESCs extract and co-cultured with mouse embryonic fibroblast in the presence of leukemia inhibitory factor (LIF). Alkaline phosphatase test and also immonohistochemistery staining for Oct4, Sox2 and Nanog were performed after 24 and 72 hours and 1 week.

RESULTS

The granulosa cells showed the alkaline phosphatase activity after 24 hours and the enzyme activity maintained for 72 hours. They also expressed Oct4 after 24 hours. The cells also expressed Sox2 and Nanog, 72 hours after exposure to the ESCs extract. The expression of the pluripotency markers decreased after 1 week. It seems that the extract can induce dedifferentiation in granulosa cells and they can express the stem cell markers. Conclusion : It seems that the inhibitors of the methyl transferase (5-Aza-Deoxycytidine) and histone deacetylase (trichostatin A) could delete the epigenetic markers and prepare the cells for reprogramming by administration of the extract.