Arun K. Bhunia

Bio: Arun K. Bhunia is an academic researcher from Purdue University. The author has contributed to research in topics: Listeria monocytogenes & Listeria. The author has an hindex of 59, co-authored 330 publications receiving 10855 citations. Previous affiliations of Arun K. Bhunia include University of Illinois at Urbana–Champaign & Center for Food Safety.

Purification, characterization and antimicrobial spectrum of a bacteriocin produced by Pediococcus acidilactici.

Abstract: An antimicrobial peptide designated pediocin AcH was isolated from Pediococcus acidilactici strain H. The pediocin AcH was purified by ion exchange chromatography. The molecular weight of pediocin AcH was determined by SDS-PAGE to be about 2700 daltons. Pediocin AcH was sensitive to proteolytic enzymes resistant to heat and organic solvents, and active over a wide range of pH. Pediocin AcH exhibited inhibition against several food spoilage bacteria and foodborne pathogens including Staphylococcus aureus, Clostridium perfringens and Listeria monocytogenes. It was bactericidal to sensitive cells and acted very rapidly. The bactericidal effect was not produced by either cell lysis or apparent loss of membrane permeability.

Efficacy of Chlorine Dioxide, Ozone, and Thyme Essential Oil or a Sequential Washing in Killing Escherichia coli O157:H7 on Lettuce and Baby Carrots

Abstract: Chlorine dioxide (ClO2), ozone, and thyme essential oil has been found to be effective in reducing pathogens, including Escherichia coli O157:H7, on selected produce. The efficacy of these sanitizers was evaluated, alone or through their sequential washing to achieve a 3 or more log reduction of mixed strains of E. coli O157:H7 on shredded lettuce and baby carrots. Samples sprinkle inoculated with mixed strains of E. coli O157:H7 were air-dried for 1 h at 22±2°C in a biosafety cabinet, stored at 4°C for 24 h, and then treated with different concentrations of disinfectants and exposure time. Sterile deionized water washing resulted in approximately 1log reduction ofE. coli O157:H7 after 10 min washing of lettuce and baby carrots. Gaseous treatments resulted in higher log reductions in comparison to aqueous washing. However, decolorization of lettuce leaves was observed during long exposure time. A logarithmic reduction of 1.48–1.97log10 cfu/g was obtained using aqueous ClO2 (10.0 mg/L for 10 min) ozonated water (9.7 mg/L for 10 min) or thyme oil suspension (1.0 mL/L for 5 min) on lettuce and baby carrots. Of the three sequential washing treatments used in this study, thyme oil followed by aqueous ClO2/ozonated water, or ozonated water/aqueous ClO2 were significantly (P<0.05) more effective in reducing E. coli O157:H7 (3.75 and 3.99log, and 3.83 and 4.34 log reduction) on lettuce and baby carrots, respectively. The results obtained from this study indicate that sequential washing treatments could achieve 3–4log reduction of E. coli O157:H7 on shredded lettuce and baby carrots.

Mode of action of pediocin AcH from Pediococcus acidilactici H on sensitive bacterial strains

Abstract: The peptide, pediocin AcH, from Pediococcus acidilactici H binds to the cell surface of Lactobacillus plantarum NCDO 955, its resistant mutant and several other sensitive and resistant Gram-positive bacteria but not to Gram-negative bacteria. Sensitive cells, following treatment with pediocin AcH, lost intracellular K ions, u.v.-absorbing materials, became more permeable to ONPG and, in some strains, lysed. Binding of pediocin AcH was maximum at pH 6.0. Anions of several salts inhibited binding of pediocin AcH but this was overcome by increased concentrations of pediocin AcH. Treatment of sensitive cells with 1% SDS, 4 mol/1 guanidine-HCl, several organic solvents and enzymes did not reduce subsequent binding of pediocin AcH. Partially purified cell wall from a sensitive strain was also able to bind pediocin AcH. However, treatment of the cell walls to remove lipoteichoic acid prevented binding. These molecules might, therefore, be one of the binding sites of pediocin AcH.

Bacteria-mediated delivery of nanoparticles and cargo into cells

Abstract: Nanoparticles and bacteria can be used, independently, to deliver genes and proteins into mammalian cells for monitoring or altering gene expression and protein production. Here, we show the simultaneous use of nanoparticles and bacteria to deliver DNA-based model drug molecules in vivo and in vitro. In our approach, cargo (in this case, a fluorescent or a bioluminescent gene) is loaded onto the nanoparticles, which are carried on the bacteria surface. When incubated with cells, the cargo-carrying bacteria ('microbots') were internalized by the cells, and the genes released from the nanoparticles were expressed in the cells. Mice injected with microbots also successfully expressed the genes as seen by the luminescence in different organs. This new approach may be used to deliver different types of cargo into live animals and a variety of cells in culture without the need for complicated genetic manipulations.

Biosensor and related method

Abstract: A microscale biosensor for use in the detection of target biological substances including molecules and cells is a microfluidic system with integrated electronics, inlet-outlet ports and interface schemes, high sensitivity detection of pathogen specificity, and processing of biological materials at semiconductor interfaces (Fig. 1). A fabrication process includes an all top-side processing for the formation of fluidic channels, planar fluidic interface ports, integrated metal electrodes for impedance measurements, and a glass cover sealing the non-planar topography of the chip using spin-on-glass as an intermediate bonding layer. Detection sensitivity is enhanced by small fluid volumes, use of a low-conductivity buffer, and electrical magnitude or phase measurements over a range of frequencies.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

“Bioinformatics” 특집을 내면서

Abstract: BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.