Differential interactions of ethacrynic acid and diethyl maleate with glutathione S-transferases and their glutathione co-factor in the house fly.

Glutathione S-transferases (GSTs) are an important class of enzymes that facilitate the conjugation of reduced glutathione (GSH) with electrophilic substrates, including some insecticides. Two inhibitors of GSTs, ethacrynic acid (EA) and diethyl maleate (DEM), are often used as diagnostic tools to implicate GST involvement in insecticide resistance, but their modes of action against insect GSTs are largely assumed based on mammalian studies. In mammalian studies, there are two proposed mechanisms of inhibition of GST function by EA and DEM: 1) scavenging or "depleting" cytosolic GSH through non-enzymatic conjugation, and 2) inhibition of GST activity directly by the inhibitor-GSH conjugate (EA-SG and DEM-SG).

A teacher-developed inquiry model to teach the molecular basis of hyperbolic kinetics in biological membrane transport.

A previously published classroom teaching method for helping students visualize and understand Michaelis-Menten kinetics (19) was used as an anticipatory set with high school and middle school science teachers in an Illinois Math and Science Partnership Program. As part of the activity, the teachers were asked to collect data by replicating the method and to analyze and report the data. All concluded that the rate data they had collected were hyperbolic.

Eicosanoids mediate insect hemocyte migration.

Hemocyte migration toward infection and wound sites is an essential component of insect defense reactions, although the biochemical signal mechanisms responsible for mediating migration in insect cells are not well understood. Here we report on the outcomes of experiments designed to test the hypotheses that (1) insect hemocytes are able to detect and migrate toward a source of N-formyl-Met-Leu-Phe (fMLP), the major chemotactic peptide from Escherichia coli and (2) that pharmaceutical modulation of eicosanoid biosynthesis inhibits hemocyte migration. We used primary hemocyte cultures prepared from fifth-instar tobacco hornworms, Manduca sexta in Boyden chambers to assess hemocyte migration toward buffer (negative control) and toward buffer amended with fMLP (positive control).

A new way to teach an old topic: the cadaver-based anatomy short course for high school students.

An outreach program has been developed at the Department of Biological Sciences, Northern Illinois University (NIU), that offers an intensive short course in human gross anatomy to high school students and their teachers. Prior to the short course, the high school teachers attend a laboratory orientation, view the facilities, and then develop a syllabus suitable for the class needs. When the students arrive, they spend between 1 and 2 days rotating through five different work stations.

Eicosanoids influence in vitro elongation of plasmatocytes from the tobacco hornworm, Manduca sexta.

Nodule formation is the predominant insect cellular defense reaction to bacterial challenges, responsible for clearing the largest proportion of infecting bacteria from hemolymph circulation. Hemocyte spreading behavior is a critical step in the nodulation process. It has been suggested that eicosanoids mediate several steps in the process.

Making tracks: the forensic analysis of footprints and footwear impressions.

Analysis of footwear characteristics, impressions, and track ways can provide important evidence in a crime scene investigation. In this article, we present examples of how students can be involved in hands-on laboratory-based activities as a means of introducing the forensic sciences. The teaching methodology employs active learning strategies that allow students to discover scientific principles for themselves, develop techniques of critical thinking and problem solving, and gain appreciation for how knowledge arises.

Lipopolysaccharide evokes microaggregation reactions in hemocytes isolated from tobacco hornworms, Manduca sexta.

Insect cellular immune reactions to bacterial infection include nodule formation. Eicosanoids mediate several cellular actions in the nodulation process, including formation of hemocyte microaggregates, an early step. In previous work, we reported that isolated hemocytes produce and secrete eicosanoids that influence hemocyte behavior in response to bacterial challenge.

Prostaglandins, not lipoxygenase products, mediate insect microaggregation reactions to bacterial challenge in isolated hemocyte preparations.

Nodulation is the predominant cellular defense reaction to bacterial challenge in insects. Eicosanoids mediate several steps in the nodulation process, including formation of hemocyte microaggregations. Isolated hemocyte preparations synthesize and secrete eicosanoids, which mediate hemocytic immune reactions.