Research Publications (Food Safety)

by Vaithish Velazhahan, Przemyslaw Glaza, Alvaro I. Herrera, Om Prakash, Michal Zolkiewski, Brian V. Geisbrecht, Kathrin Schrick

Antibiotic residues in consumer foods pose a threat to human health and contribute to increasing antimicrobial resistance. The study was conducted from January to July 2019 in six provinces in Viet Nam. In total, 360 pork samples and 360 chicken meat samples were collected for analysis. The samples were first screened with an ELISA test kit for residues in the beta-lactam, tetracycline and sulfonamide groups.

Viridicatumtoxins are a rare class of tetracycline-like antibiotics that strongly inhibit drug-resistant Gram-positive bacteria. Although reported to exhibit in vitro inhibition activity to undecaprenyl pyrophosphate synthase (UPPS), an essential enzyme in bacterial cell wall synthesis, the biological targets and mechanism of action of viridicatumtoxins, especially the drug–target interactions, remain largely unknown.

Infant formulas are manufactured products to meet specific nutritional requirements for infants. However, infant formulas can contain harmful substances, such as chemical contaminants and residues, normally due to possible contamination of the raw material or from the production chain. Some studies have demonstrated that veterinary drugs, pesticides, mycotoxins, heavy metals, packaging materials, within other chemicals are found in infant formulas from different sources of contamination.

Fluralaner, a veterinary drug, is a potential chiral isoxazoline insecticide possessing high insecticidal and acaricidal activity. However, there is little information regarding the enantioselective effect of fluralaner. In this work, a promising chiral detection method was established with liquid chromatography–mass spectrometry in agricultural products and animal organs to investigate enantioselective metabolism and bioactivity.

Cytochrome bd (cyt-bd) oxygen reductases have a high affinity to oxygen and use the two electrons provided by ubiquinol or menaquinol, like in mycobacteria, to reduce oxygen to water. Although they do not pump protons from the cytoplasmic to the periplasmic side, they generate a proton motive force due to the release of protons after quinol oxidation.

by Awwad Radwan, Gamal M. Mahrous

Many bisphenol A (BPA) analogs have been commercially used recently, such as 2,2-bis(4-hydroxyphenyl)butane (BPB), 4,4′-ethylidenebisphenol, 4,4′-methylenediphenol (BPF), 4,4′-(1,4-phenylenediisopropylidene)bisphenol (BPP), 4,4′-dihydroxydiphenyl sulfone (BPS), 4,4′-cyclohexylidenebisphenol (BPZ), 4,4′-(hexafluoroisopropylidene)diphenol (BPAF), 4,4′-(1-phenylethylidene)bisphenol (BPAP), and 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane (TMBPA), to circumvent adverse effects of BPA.

by Saki Sultana, Jacklyn Stewart, Aarnoud C. van der Spoel

The fungi Paracoccidioides brasiliensis and Paracoccidioides lutzii are the causative agents of paracoccidioidomycosis (PCM), a systemic mycosis endemic to Latin America. This fungus is considered a facultative intracellular pathogen that is able to survive and replicate inside macrophages. The survival of the fungus during infection depends on its adaptability to various conditions, such as nitrosative/oxidative stress produced by the host immune cells, particularly alveolar macrophages.

by Kelsey Brown, Maina Mugoh, Douglas R. Call, Sylvia Omulo

Multidrug resistance (MDR) transporters of the major facilitator superfamily (MFS) were previously believed to drive the extrusion of multiple antimicrobial drugs through the coupling to proton translocation. Here, we present the identification of the first Na+-coupled MFS-MDR transporter, MdrP, which also can achieve H+-coupled drug efflux independently of Na+.

Author(s): Sihui Liang, Ningge Jian, Jiankun Cao, Huayin Zhang, Jian Li, Qian Xu, Chunmin Wang

Author(s): Elena Bartkiene, Modestas Ruzauskas, Vadims Bartkevics, Iveta Pugajeva, Paulina Zavistanaviciute, Vytaute Starkute, Egle Zokaityte, Vita Lele, Agila Dauksiene, Michael Grashorn, Ludwig E. Hoelzle, Anara Mendybayeva, Raushan Ryshyanova, Romas Gruzauskas

Background Iprodione has better control effect, but it is considered an endocrine disturbing chemical and it could inflict some serious damage to consumers. The garlic crop has three edible portions based on its growth stage, including the garlic, green garlic and garlic shoot. In this study, iprodione residue dissipation and distribution on these three edible portions were investigated, and dietary risk assessment was evaluated.

Bacteriophage-derived endolysin enzymes play a critical role in disintegration of the host bacterial cell wall and hence have gained considerable attention as possible therapeutics for the treatment of drug-resistant infections. Endolysins can target both dividing and non-dividing cells and given the vital role peptidoglycan plays in bacterial survival, bacteria are less likely to modify it even if continuously exposed to lysins.

Antimicrobial peptides (AMPs) have attracted more attention for their potential candidates for new antibiotic drugs. As a novel identified cathelicidin AMP from duck, dCATH owns broad-spectrum antimicrobial activities but with a noticeable toxicity. To explore dCATH-derived AMPs with reduced cell toxicity and improved cell selectivity, a series of truncated and tryptophan-replaced peptides of dCATH were designed.

An antifungal lipodepsipeptide was obtained from cultures of the fungus Foliophoma fallens CF-236885. Its structure, elucidated by HRMS and NMR spectroscopy, contained Gly, Thr, Asn, β-Ala, Orn, Ala, two Ser residues, and 3-hydroxy-4-methylhexadecanoic acid.

Author(s): Yuming Hu, Yunpeng Shen, Jianlong Wang

Significance and Impact of the Study: Vibrio harveyi is a major pathogen of marine animals. The bacterium could enter into a viable but non‐culturable state (VBNC) state when exposed to harsh conditions, and retains its pathogenicity after resuscitation. In this work, we analysed the enzyme activities of a resuscitation‐promoting factor YeaZ and the relationship of protease activities with its promoting effect on the resuscitation of VBNC cells.

Multidrug resistance among Gram-negative bacteria is a major global public health threat. Metallo-β-lactamases (MBLs) target the most widely used antibiotic class, the β-lactams, including the most recent generation of carbapenems. Interspecies spread renders these enzymes a serious clinical threat, and there are no clinically available inhibitors.

Author(s): Dongmei Xu, Hua Pan, Jiachao Yao, Yixuan Feng, Panpan Wu, Kai Shao

Host defense peptides (HDPs), also known as antimicrobial peptides, are naturally occurring polypeptides (~12–50 residues) composed of cationic and hydrophobic amino acids that adopt an amphipathic conformation upon folding usually after contact with membranes. HDPs have a variety of biological activities including immunomodulatory, anti-inflammatory, anti-bacterial, and anti-biofilm functions.

Ebola virus (EBOV), the causative pathogen of the deadly EBOV disease (EVD), can be transmitted via sexual transmission. Seminal amyloid fibrils have been found enhancers of EBOV infection. Currently, limited preventive vaccine or therapeutic is available to block EBOV infection through sexual intercourse.

The burden of antibiotic resistance necessitates a continued search for new antimicrobials. We evaluated the antimicrobial activities of novel benzothiazoles synthesized by our group. Antibacterial activity was evaluated in vitro in Staphylococcus aureus, Bacillus subtilis, and Escherichia coli, while the antifungal activity was tested in Candida albicans and Aspergillus niger, and expressed as the minimum inhibitory concentration (MIC; µg/mL).