The QuantiPhage assay: A novel method for the rapid colorimetric detection of coliphages using cellulose pad materials

Development of a multilayer insect-repelling film with trans-anethole for the storage of almond flake cereal

Trans-anethole (AN), which exhibits strong insect-repellent activity against Plodia interpunctella larvae, was applied on a polyethylene terephthalate (PET) film as an active packaging coating layer. All developed films at different concentrations (25%, 30%, 40%, and 50%) exhibited significant insect repellent activities. However, these films did not significantly differ from the control film in terms of color and transparency. In addition, the developed polypropylene (PP) and PET laminated films containing 25% AN (PP/AN25/PET) exhibited strong and continuous insect-repellent activity for up to 42 days. Finally, the developed film showed 2.86-fold stronger repellent activity than that of the control film when applied to the almond flake cereals packaging. These results suggest that PP/AN25/PET could be used as a potent insect-repelling packaging film in a realistic grain-packaging system. PRACTICAL APPLICATION: A PP/trans-anethole/PET film that exhibited good insect-repellent activity for 42 days was newly developed in this study. As it showed strong insect repellency, especially in almond flake cereals packaging, it is expected to have high potential as an insect-repelling grain-packaging film.

Bacteriophages as Fecal Pollution Indicators

Bacteriophages are promising tools for the detection of fecal pollution in different environments, and particularly for viral pathogen risk assessment. Having similar morphological and biological characteristics, bacteriophages mimic the fate and transport of enteric viruses. Enteric bacteriophages, especially phages infecting Escherichia coli (coliphages), have been proposed as alternatives or complements to fecal indicator bacteria. Here, we provide a general overview of the potential use of enteric bacteriophages as fecal and viral indicators in different environments, as well as the available methods for their detection and enumeration, and the regulations for their application.

F-specific coliphage detection by the Bluephage method

F-specific coliphages have been proposed as viral indicators of fecal pollution. These intestinal phages infect cells through the F-pili of the host strains used for their detection, Escherichia. coli HS/FAmp in the US-EPA standard method and Salmonella enterica WG49 in the ISO method. The recently designed Bluephage protocol allows the rapid detection of as low as one somatic coliphage in a working day. The current study describes a new Bluephage method designed to exclusively detect F-specific phages. It employs two new host strains, CB14 and CB16, which detect the same number of F-specific phages as their respective parental strains HS and WG49. In the Bluephage method, when the strain is lysed by bacteriophage infection, the yellow medium turns blue. As low as one F-specific phage was detected in 3 to 5 h by this approach and when the sample contained high phage concentrations, results were obtained in less than 3 h. The F-specific Bluephage method can be used with different sample volumes and allows phage quantification by the most probable number technique. Strain CB14 performed more consistently than CB16, with comparable detection efficiency after increasing the incubation time to 50 min without shaking.

Reporter Phage-Based Detection of Bacterial Pathogens: Design Guidelines and Recent Developments

Fast and reliable detection of bacterial pathogens in clinical samples, contaminated food products, and water supplies can drastically improve clinical outcomes and reduce the socio-economic impact of disease. As natural predators of bacteria, bacteriophages (phages) have evolved to bind their hosts with unparalleled specificity and to rapidly deliver and replicate their viral genome. Not surprisingly, phages and phage-encoded proteins have been used to develop a vast repertoire of diagnostic assays, many of which outperform conventional culture-based and molecular detection methods. While intact phages or phage-encoded affinity proteins can be used to capture bacteria, most phage-inspired detection systems harness viral genome delivery and amplification: to this end, suitable phages are genetically reprogrammed to deliver heterologous reporter genes, whose activity is typically detected through enzymatic substrate conversion to indicate the presence of a viable host cell. Infection with such engineered reporter phages typically leads to a rapid burst of reporter protein production that enables highly sensitive detection. In this review, we highlight recent advances in infection-based detection methods, present guidelines for reporter phage construction, outline technical aspects of reporter phage engineering, and discuss some of the advantages and pitfalls of phage-based pathogen detection. Recent improvements in reporter phage construction and engineering further substantiate the potential of these highly evolved nanomachines as rapid and inexpensive detection systems to replace or complement traditional diagnostic approaches.