Ashok Mulchandani

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The metalloregulatory protein ArsR, which offers high affinity and selectivity toward arsenite, was overexpressed in Escherichia coli in an attempt to increase the bioaccumulation of arsenic. Overproduction of ArsR resulted in elevated levels of arsenite bioaccumulation but also a severe reduction in cell growth. Incorporation of an elastin-like polypeptide(More)
Surface display is a powerful technique that uses natural microbial functional components to express proteins or peptides on the cell exterior. Since the reporting of the first surface-display system in the mid-1980s, a variety of new systems have been reported for yeast, Gram-positive and Gram-negative bacteria. Non-conventional display methods are(More)
The use of plants for rehabilitation of heavy-metal-contaminated environments is an emerging area of interest because it provides an ecologically sound and safe method for restoration and remediation. Although a number of plant species are capable of hyperaccumulation of heavy metals, the technology is not applicable for remediating sites with multiple(More)
Phytochelatins (PCs) with good binding affinities for a wide range of heavy metals were exploited to develop microbial sorbents for cadmium removal. PC synthase from Schizosaccharomyces pombe (SpPCS) was overexpressed in Escherichia coli, resulting in PC synthesis and 7.5-times-higher Cd accumulation. The coexpression of a variant gamma-glutamylcysteine(More)
Approximately 89 million metric t of organic chemicals and lubricants, the majority of which are fossil based, are produced annually in the United States. The development of new industrial bioproducts, for production in stand-alone facilities or biorefineries, has the potential to reduce our dependence on imported oil and improve energy security. Advances(More)
We report herein a whole cell-based amperometric biosensor for highly selective, highly sensitive, direct, single-step, rapid, and cost-effective determination of organophosphate pesticides with a p-nitrophenyl substituent. The biosensor was comprised of a p-nitrophenol degrader, Pseudomonas putida JS444, genetically engineered to express organophosphorus(More)
Organophosphorus hydrolase (OPH) is a bacterial enzyme that has been shown to degrade a wide range of neurotoxic organophosphate nerve agents. However, the effectiveness of degradation varies dramatically, ranging from highly efficient with paraoxon to relatively slow with methyl parathion. Sequential cycles of DNA shuffling and screening were used to(More)
Environmental monitoring relies on compact, portable sensor systems capable of detecting pollutants in real-time. An integrated chemical sensor array system is developed for detection and identification of environmental pollutants in diesel and gasoline exhaust fumes. The system consists of a low noise floor analog front-end (AFE) followed by a signal(More)
Molecular beacons are oligonucleotide probes that become fluorescent upon hybridization. We developed a real-time PCR assay to detect the presence of Salmonella species using these fluorogenic reporter molecules. A 122-base-pair section of the himA was used as the amplification target. Molecular beacons were designed to recognize a 16-base-pair region on(More)
In this study, a molecular-beacon-based real-time reverse transcription (RT)-PCR assay was developed to detect the presence of hepatitis A virus (HAV) in environmental samples. A 125-bp, highly conserved 5' noncoding region of HAV was targeted. The sensitivity of the real-time RT-PCR assay was tested with 10-fold dilutions of viral RNA, and a detection(More)