Detection of bacteriophage infection and prophage induction in bacterial cultures by means of electric DNA chips

Abstract

Infections of bacterial cultures by bacteriophages are common and serious problems in many biotechnological laboratories and factories. A method for specific, quantitative, and quick detection of phage contamination, based on the use of electric DNA chip is described here. Different phages of Escherichia coli and Bacillus subtilis were analyzed. Phage DNA was isolated from bacterial culture samples and detected by combination of bead-based sandwich hybridization with enzyme-labeled probes and detection of the enzymatic product using silicon chips. The assay resulted in specific signals from all four tested phages without significant background. Although high sensitivity was achieved in 4h assay time, a useful level of sensitivity (10(7)-10(8) phages) is achievable within 25 min. A multiplex DNA chip technique involving a mixture of probes allows for detection of various types of phages in one sample. These analyses confirmed the specificity of the assay.

A fast and reliable method for monitoring of prophage‐activating chemicals

“…Thorough sample purification along with a specific pre‐treatment prior to the analysis are prerequisites for all of these methods, making them rather less suitable for fast high‐throughput analysis and requiring highly qualified personnel. A sophisticated method that solves the high‐throughput problem and promises short detection times is based on electric chips, for instance, for DNA (Gabig‐Ciminska et al ., 2004). Here is the main problem the development and cost‐intensive production of bead immobilized capture probes and the requirement of sample preparation.…”

Towards development of chemosensors and biosensors with metal-oxide-based nanowires or nanotubes

“…Although metal-oxide-based nanotubes are widely reported, their applications in electrochemical sensors are fewer. The main problems may lie in the fact that there exists difficulty in the pretreating nanotubes powder (Gabig-Ciminska et al, 2004) to obtain dispersible phase. Moreover, most nanotubes lack of electrochemical activity.…”

On-chip impedimetric detection of bacteriophages in dairy samples

“…However, this is a laborious and expensive technique, and requires high technical expertise for conducting such assays, which makes the implementation of the method for routine analysis in industry still difficult. Moreover, another major problem common to all DNA-based detection methods, including the recently described method using electric DNA chips (Gabig-Ciminska et al, 2004), is that they can only detect bacteriophages whose sequence is already known. The advances in the last decades in the biosensor technology have improved and simplified the detection of multiple analytes in complex samples by the development of different electrochemical, piezoelectric, magnetic, and optical biosensors.…”

“…bacteria carrying a latent prophage in their chromosome) are the main causes leading to bacteriophage contamination in this field. For instance, spontaneous prophage induction of bacterial strains used in the preparation of the starter cultures can easily lead to a phage titter of around 10 2 -10 5 plaque forming units per mL (PFU mL −1 ) in a typical 100 L bioreactor (Gabig-Ciminska et al, 2004).…”