A simple method for detecting genetically modified maize in common food products

Curriculum and course materials for a forensic DNA biology course

The Forensic Science Education Programs Accreditation Commission (FEPAC) requires accredited programs offer a "coherent curriculum" to ensure each student gains a "thorough grounding of the natural…sciences." Part of this curriculum includes completion of a minimum of 15 semester-hours forensic science coursework, nine of which can involve a class in forensic DNA biology. Departments that have obtained or are pursuing FEPAC accreditation can meet this requirement by offering a stand-alone forensic DNA biology course; however, materials necessary to instruct students are often homegrown and not standardized; in addition, until recently, the community lacked commercially available books, lab manuals, and teaching materials, and many of the best pedagogical resources were scattered across various peer-reviewed journals. The curriculum discussed below is an attempt to synthesize this disparate information, and although certainly not the only acceptable methodology, the below discussion represents "a way" for synthesizing and aggregating this information into a cohesive, comprehensive whole.

A practical home-made microcentrifuge for teaching purposes

We report a practical home-made microcentrifuge to be used for teaching purposes. It was made using a salad spinner and two polymerase chain reaction (PCR) tubes racks. It can accommodate 2 standard size 96-well plates or 24 strips or up to 192 microfuge tube. The centrifuge is hand-operated and is ideal for short spin down purposes.

PCR cloning of partial nbs sequences from grape (Vitis aestivalis Michx)

Plants defend themselves against pathogens via the expressions of disease resistance (R) genes. Many plant R gene products contain the characteristic nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains. There are highly conserved motifs within the NBS domain which could be targeted for polymerase chain reaction (PCR) cloning of R genes. Here, we report a 4-week undergraduate laboratory exercise that mimics the research environment to PCR-clone partial nbs sequences using degenerate primers corresponding to the phosphate-binding loop (P-loop) and GLPL motifs within the NBS domain of potential R gene products from the North American grape, Vitis aestivalis Michx. Students were able to complete the laboratory procedures successfully and obtained four different clones, among which three are new. Through the laboratory exercise, students learned a variety of important molecular techniques including genomic DNA isolation, DNA quantification, PCR, agarose gel electrophoresis, DNA extraction from agarose gel, ligation, bacterial transformation, and plasmid DNA isolation and purification. They also used currently available web-based bioinformatic programs for sequence analysis. The laboratory exercise provides students the hands-on experience on PCR cloning and shows them how it is done in a research environment. The clones obtained may be further tested for their potential use as markers to differentiate resistant cultivars from the susceptible ones, a useful tool in breeding programs.

Screening of lactic acid bacteria for bacteriocins by microbiological and PCR methods

We describe a practical laboratory designed for third-year undergraduate students of Biotechnology as part of a Microbial Physiology and Genetics course. It comprises a five-session laboratory module to screen foods for lactic acid bacteria (LAB)1 and to test isolated LAB for the presence of bacteriocins. Traditional Thai fermented foods are first screened for bacteriocin-producing LAB using microbiological methods. This is followed by a simple and rapid DNA extraction and by a multiplex polymerase chain reaction (PCR) using three pairs of specific primers to test for the presence or absence of various bacteriocin genes in the isolated LAB. PCR amplicons of 332, 412, and 608 bp indicate the presence of pediocin, enterocin, and nisin genes, respectively, whereas no amplicon band indicates the absence of these bacteriocins. The laboratory provides the students with experience in the use of microbiological and multiplex PCR methods and shows how the molecular biology techniques can be related to their daily lives. The module could easily be adapted to the study of fermented foods from other countries.