Research Publications (Food Safety)

Autotransporters are a superfamily of virulence factors secreted by Gram negative bacteria. They are comprised of an N-terminal passenger domain that is translocated across the outer membrane, and a C-terminal domain that inserts into the outer membrane forming a β-barrel anchor. It is still poorly understood how the passenger is efficiently translocated in the absence of external energy inputs.

An exoprotease of Vibrio vulnificus, VvpS, exhibits an autolytic function during the stationary phase. To understand how vvpS expression is controlled, the regulators involved in vvpS transcription and their regulatory mechanisms were investigated. LeuO was isolated in a ligand-fishing experiment, and experiments using a leuO-deletion mutant revealed that LeuO represses vvpS transcription. LeuO bound the extended region including LeuO-binding site (LBS)-I and LBS-II.

Publication date: October 2015
, Volume 56
Author(s): Sudarsan Mukhopadhyay , Dike O. Ukuku , Vijay K. Juneja

Cary Pirone-Davies, Maria Hoffmann, Richard J. Roberts, Tim Muruvanda, Ruth E. Timme, Errol Strain, Yan Luo, Justin Payne, Khai Luong, Yi Song, Yu-Chih Tsai, Matthew Boitano, Tyson A. Clark, Jonas Korlach, Peter S. Evans, Marc W. Allard

Vibrio cholerae is a severe human pathogen and a frequent member of aquatic ecosystems. Quantification of V. cholerae in environmental water samples is therefore fundamental for ecological studies and health risk assessment. Beside time-consuming cultivation techniques, quantitative PCR (qPCR) has the potential to provide reliable quantitative data and offers the opportunity to quantify multiple targets simultaneously.

Methylmercury is a potent neurotoxin that is produced by anaerobic microorganisms from inorganic mercury by a recently discovered pathway. A two-gene cluster, consisting of hgcA and hgcB, encodes two of the proteins essential for this activity. hgcA encodes a corrinoid protein with a strictly conserved cysteine proposed to be the ligand for cobalt in the corrinoid cofactor, whereas hgcB encodes a ferredoxin-like protein thought to be an electron donor to HgcA.

Haemophilus parasuis, the causative agent of Glässer's disease, is one of the early colonizers of the nasal mucosa of piglets. It is prevalent in swine herds, and lesions associated with disease are fibrinous polyserositis and bronchopneumonia. Antibiotics are commonly used in disease control, and resistance to several antibiotics has been described in H. parasuis. Prediction of H. parasuis virulence is currently limited by our scarce understanding of its pathogenicity.

To examine to what extent fresh vegetables imported into Switzerland represent carriers of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae, 169 samples of different types of fresh vegetables imported into Switzerland from the Dominican Republic, India, Thailand, and Vietnam were analyzed. Overall, 25.4% of the vegetable samples yielded one or more ESBL-producing Enterobacteriaceae, 78.3% of which were multidrug resistant.

Fifty-nine monophasic Salmonella enterica serovar Typhimurium isolates, collected in Belgium during the period from 2008 to 2011, have been serotyped as 4,[5]:i:– and shown to harbor an fljB coding sequence. The genetic differences between these strains and phenotypically biphasic Salmonella Typhimurium were analyzed through PCR and DNA sequencing. Genetic alterations in the fljB promoter region affecting expression of the phase 2 flagellin were observed in 53 isolates.

Salmonella enterica serovar Enteritidis is a major foodborne pathogen in the United States, causing gastroenteritis in humans, primarily through consumption of contaminated eggs. Chickens are the reservoir host of S. Enteritidis. In layer hens, S. Enteritidis colonizes the intestine and migrates to various organs, including the oviduct, leading to egg contamination.

Publication date: 15 October 2015
, Volume 185
Author(s): D. James Bound , Pushpa S. Murthy , P. Srinivas

Publication date: 15 October 2015
, Volume 185
Author(s): Yi Zhao , Mingshun Chen , Zhengang Zhao , Shujuan Yu

Listeriolysin O (LLO), an essential virulence determinant of Listeria monocytogenes, is a pore-forming toxin whose primary function is to facilitate cytosolic bacterial replication by breaching the phagosomal membranes, which is critical for the pathogen to evade host immune recognition. The critical role of LLO in the virulence of L. monocytogenes renders it an ideal target for designing novel antivirulence therapeutics.

Publication date: 16 July 2015
, Volume 205
Author(s): Luís Gustavo Corbellini , Ana Sofia Ribeiro Duarte , Leonardo Víctor de Knegt , Luis Eduardo da Silva , Marisa Cardoso , Maarten Nauta

e-First Articles.

Publication date: October 2015
, Volume 56
Author(s): Haiying Cui , Chengting Zhao , Lin Lin

Meer T. Alam, Thomas A. Weppelmann, Ira Longini, Valery Madsen Beau De Rochars, John Glenn Morris, Afsar Ali

RecQ helicases unwind remarkably diverse DNA structures as key components of many cellular processes. How RecQ enzymes accommodate different substrates in a unified mechanism that couples ATP hydrolysis to DNA unwinding is unknown. Here, the X-ray crystal structure of the Cronobacter sakazakii RecQ catalytic core domain bound to duplex DNA...

Feng Xu, Saba Ilyas, Jeffrey A. Hall, Stephen H. Jones, Vaughn S. Cooper and Cheryl A. Whistler Gastric infections caused by the environmentally transmitted pathogen, Vibrio parahaemolyticus, have increased over the last two decades, including in many parts of the United States (US). However, until recently, infections linked to shellfish from the cool northeastern US waters were rare. Cases have risen in the Northeast, consistent with changes in local V.

Publication date: October 2015
, Volume 56
Author(s): Ravirajsinh Jadeja , Marlene E. Janes , Janet G. Simonson

Publication date: 2 July 2015
, Volume 204
Author(s): Veerachandra K. Yemmireddy , Yen-Con Hung

Publication date: 2 July 2015
, Volume 204
Author(s): Nina Bjerre Østergaard , Lasse Engbo Christiansen , Paw Dalgaard

Publication date: 2 July 2015
, Volume 204
Author(s): Junping Wang , Xinfang Xie , Jinsong Feng , Jessica C. Chen , Xin-jun Du , Jiangzhao Luo , Xiaonan Lu , Shuo Wang

Publication date: 2 July 2015
, Volume 204
Author(s): C. Plaza-Rodríguez , C. Thoens , A. Falenski , A.A. Weiser , B. Appel , A. Kaesbohrer , M. Filter