Isolation and detection of Listeria monocytogenes using fluorogenic and chromogenic substrates for phosphatidylinositol-specific phospholipase C.

The BCM Listeria monocytogenes detection system (LMDS) consists of a selective preenrichment broth (LMPEB), selective enrichment broth (LMSEB), selective/differential plating medium (LMPM), and identification on a confirmatory plating medium (LMCM). The efficacy of the BCM LMDS was determined using pure cultures and naturally and artificially contaminated environmental sponges. The BCM LMPEB allowed the growth of Listeria and resuscitation of heat-injured L.

A 5-h screening and 24-h confirmation procedure for detecting Escherichia coli O157:H7 in beef using direct epifluorescent microscopy and immunomagnetic separation.

An antibody-direct epifluorescent filter technique (Ab-DEFT) detected 100% of the raw ground beef samples inoculated with Escherichia coli O157:H7 cells (0.15 cells g-1) and incubated in a prewarmed, modified buffered peptone water (mBPW) non-selective enrichment broth for 5 h at 42 degrees C in an orbital shaking water bath (200 rev min-1). Over 50% of the microscopic fields viewed were positive (1-10 fluorescent cells field-1) in the Ab-DEFT.

Gram staining apparatus for space station applications.

A self-contained, portable Gram staining apparatus (GSA) has been developed for use in the microgravity environment on board the Space Station Freedom. Accuracy and reproducibility of this apparatus compared with the conventional Gram staining method were evaluated by using gram-negative and gram-positive controls and different species of bacteria grown in pure cultures. A subsequent study was designed to assess the performance of the GSA with actual specimens.

Prophage (phi 80) induction in Escherichia coli K-12 by specific deoxyoligonucleotides.

A cell preparation that is permeable to proteins and oligonucleotides yet produces infectious phage particles after induction treatments was obtained by plasmolysis of Escherichia coli cells lysogenic for phi 80. When the permeabilized cells were exposed to specific oligo(deoxynucleotides), prophage (phi 80) was induced during further incubation. Of the dinucleotides tested, only d(A-G), d(G-G), and d(I-G) induced prophage.