Two different strains of yeast, Saccharomyces cerevisiae, AP22 and CCFY-100 were studied for bioaccumulation of gold in the form of H198AuCl4. Thin sectioning and subsequent study by transmission electron microscopy (TEM) reveals that Au3+ was in situ reduced to Au(0) and nano sized gold particles were formed inside the cell. Very low dose γ-energy being responsible for reduction of cationic gold in the polymeric cytoplasm matrix. The formation and entry of gold nanoparticles in the yeast cells were studied as a function of time at certain intervals starting from 15min to 72h. The gold nanoparticles gradually moved inward as a function of time from cell wall to cytoplasm to nucleus and finally accumulated in the nucleolus of the cell. TEM image of budding yeast shows that gold nanoparticles are not transferred to the new generation yeast cells. © 2011 Elsevier B.V.

KAMALIKA SEN

Chemistry

P SINHA

S LAHIRI

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

&nbsp;

The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

&nbsp;

It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Biochemical Engineering Journal

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. © 2016, The Author(s).

Fulltext

AMB Express

Whole resting cells vs. cell free extracts of Candida parapsilosis ATCC 7330 for the synthesis of gold nanoparticles

The bioaccumulation of 198Au radionuclide, by Rhizoclonium riparium a member of Chlorophyceae has been studied. It has been observed that accumulation of gold on Rhizoclonium is almost pH independent and slightly higher at basic pH. Accumulation of gold was studied with 198Au radiotracer, 0.1, 1 and 5 ppm concentrations of gold. It has been concluded from the biochemical analysis that the gold accumulation is due to adsorption in the cellulose and not in protein, fat and carbohydrate. Accumulated gold was recovered when washed with conc. HNO3. © 2006 Akadémiai Kiadó.

Journal of Radioanalytical and Nuclear Chemistry

Preconcentration of 198 Au in a green alga, Rhizoclonium

Nanoparticle (NP)-Based Delivery Vehicles

An introduction to drug/gene delivery systems

Materials Science and Engineering: C

Biomineralization of iron phosphate nanoparticles in yeast cells

Analytical Chemistry

In Situ γ-Radiation: One-Step Environmentally Benign Method To Produce Gold−Palladium Bimetallic Nanoparticles

Journal of Natural Products

The Chemistry and Biology of Winemaking. By Ian  Hornsey (Northgate Brewery). Royal Society of Chemistry, Cambridge. 2007. xii + 458 pp. 6 × 9 in. £29.95 ISBN 9780854042661 .

Time dependent formation of gold nanoparticles in yeast cells: A comparative study

Journal	Data powered by TypesetBiochemical Engineering Journal
Publisher	Data powered by TypesetELSEVIER SCIENCE SA
ISSN	1369-703X