A procedure that allows students to view an entire bacterial growth curve during a two- to three-hour student laboratory period is described. Observations of the lag phase, logarithmic phase, maximum stationary phase, and phase of decline are possible. A nonpathogenic, marine bacterium is used in the investigation. (KR)

A study investigated the efficacy of glutaraldehyde and several other disinfectants for disinfecting teeth to be used for teaching and research, as an alternative to autoclaving for teeth with amalgam restorations. Results indicate that formalin was the only disinfectant that penetrated tooth pulp chambers in effective antimicrobial…

An exercise that uses a common bacterium, E. coli, in great numbers, to detect a demonstrable change in the ability of some cells to become resistant to the common antibiotic streptomycin is presented. The procedure for preparing and pouring the gradient antibiotic plates is provided. The advantages of using the Basic Fuchsin in the agar are…

Rapid-cycling brassicas can be used in the classroom to teach concepts such as plant growth, tropisms, floral reproduction, pollination, embryonic development, and plant genetics. Directions on how to obtain them for classroom use and how they may be grown are included. Practical physiology and genetics exercises are listed. (KR)

Presents a protocol that can be used to discover that S. marcescens produces a bright red pigment when exposed to one temperature condition and does not produce this color under other conditions. Enables students to connect gene expression and environmental changes. (DDR)

Describes an experiment in which the density of solutions of known sugar concentrations is measured. Data are then used to determine sugar content in commercial beverages. (DDR)

Presents a relatively short, simple, safe, and visual method for student preparation of chlorine, bromine, and iodine using reactants and glassware that are easy to obtain and handle. (WRM)

Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

Presents an experiment aimed at constructing a genomic library that can be carried out over a week. Helps students learn concepts such as donor and vector DNAs, construction of recombinant DNA, host strain, and experiments in gene cloning more clearly. (PVD)

Demonstrates how leaf slices provide an inexpensive material for illustrating several fundamental points about the biochemistry of photosynthesis and respiration. Presents experiments that illustrate the effects of photon flux density and herbicides and carbon dioxide concentration. (DDR)

Argues that the debate on whether to use performance-based versus prescriptive measurement approaches to environmental measurements is unnecessary. Believes that, as project managers gain more experience using data-quality objectives, the performance-based approach will become more popular. (MDH)

Describes an experiment in which plasmid DNA is digested with restriction enzymes that cleave the plasmid either once or twice. The DNA is stained, loaded on a gel, electrophoresed, and viewed under normal laboratory conditions during electrophoresis. (DDR)

Describes the study of dung-inhabiting or coprophilous fungi to illustrate basic lab techniques and fundamental ecological concepts. Contains 24 references. (WRM)

Presents methods that can be used to isolate the enzyme tyrosinase and to assay its activity. Lists instructions for a laboratory activity that has variable but frequently dramatic results. (WRM)

The present research describes an efficient procedure to obtain high levels of trypsinogen and chymotrypsinogen by using a simple, rapid, and easily reproducible method. The extraction process and the time-course of activation of zymogens can be carried out in a single laboratory period, without sophisticated equipment. The main objective was to…