Staining of Nuclei in Fungi by Ethidium Bromide

Ethidium bromide, (0.1% solution in ethanol-water, 1:3, v/v) was used to stain nuclei in mycelia and spores of different fungi. Nuclei looked bright brick red under green excitation. This method is very efficient, specific, reproducible and cost-effective.     

Cats as an aid to teaching genetics

I have used an exercise involving domestic cats in the General Genetics course at the University of Nebraska-Lincoln for the past 5 years. Using a coherent set of traits in an organism familiar to the students makes it easy to illustrate principles of transmission and population genetics. The one-semester course consists primarily of sophomores and juniors who have either taken a one-semester introductory biology course, a one-semester cell biology course, or have a strong high school biology background. The students are given a handout and asked to determine the genotype at seven unlinked loci of at least one cat. To fill out the form, the students have to grasp such concepts as dominance, incomplete dominance, temperature-sensitive mutations, epistatic interactions, sex linkage, and variable expressivity. Completing the form reinforces these concepts as they observe the cat's phenotype and fill in the genotype. I then analyze the collected data and use it in my lectures on population genetics to illustrate the Hardy-Weinberg equilibrium, calculate allele frequencies, and use statistics. This allows the students to look at population genetics in a very positive light and provides concrete examples of some often misunderstood principles.     

Molecular simulation as an aid to experimentalists

Computer-based molecular simulation techniques are increasingly used to interpret experimental data on biomolecular systems at an atomic level. Direct comparison between experiment and simulation is, however, seldom straightforward. The available experimental data are limited in scope and generally correspond to averages over both time and space. A critical analysis of the various factors that may influence the apparent degree of agreement between the results of simulations and experimentally measured quantities is presented and illustrated using examples from recent literature.     

Rapid Staining of Nuclei and Chromosomes in Root Tips

Feulgen reagent quickly heated to and maintained at 60 C just before immersion of plant material, basic fuchsin in acid alcohol at room temperature, and pinacyanol at room temperature will stain hydrolyzed root tip nuclei and chromosomes in one minute or less. This technic, coupled with fast fixation, can be utilized when uncertainties exist as to when to begin sampling plant meristem cells for mitoses or when time does not allow for standard fixation and Schiff staining.     

Sodium dodecyl sulphate--polyacrylamide gel electrophoresis of cell-surface proteins as an aid to the identification of the Bacteroides fragilis group.

The outer-membrane complexes from 40 strains of Bacteroides, representing eight of the species included in the Bacteroides fragilis group, were released by EDTA treatment. The component polypeptides were examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis on slab gels. Within a species (biotype) the patterns produced indicated marked similarities in the structures of the surface proteins among the strains examined. The patterns produced by strains belonging to different species, however, showed fewer similarities. An unknown organism could therefore be identified to species level using this technique and a few selected biochemical tests.     

Droperidol-fentanyl as an aid to blood collection in rabbits

Administration of a droperidol-fentanyl combination to laboratory rabbits at a dose of 2.5 mg/kg and 0.05 mg/kg body weight, respectively, produced vasodilatation which greatly facilitated blood withdrawal from the central auricular artery. The method eliminated the need for vacuum devices or topical irritants and posed little risk or discomfort to the animal.     

Cellulases as an aid to enhance saccharification of cassava root

Summary The conventional saccharification of cassava root by enzymatic hydrolysis is improved by using a little amount of cellulase and cellobiase in addition to conventional enzyme, glucoamylase. With new saccharification[glucoamylase 0.45SGU/g cassava, cellulase 4.5NCU/g cassava, cellobiase 0.09U/g cassava, pH 4.3, temperature 60°C, total volume 465ml : 100g of cassava/400ml of water], the reaction time was reduced by about 5 hours, the concentration of reducing sugar was increased by 40%, glucose production was enhanced by 10% , and the viscosity was reduced by 30%.     

Mechanics as an aid to interpreting pollen structure and function

Pollen walls can be viewed, like all other structural entities, as bodies subject to the laws of mathematics and mechanics. This view is compatible with an interpretation of pollen biology in terms of water relations. Some basic mathematical and mechanical relationships are discussed, including scaling effects, and these applied to Compositae pollen.     

Metabolite profiling as an aid to metabolic engineering in plants

The past decade has seen some impressive successes in the metabolic engineering of biotechnologically important plant pathways. However, plant metabolic engineering currently proceeds more by trial and error than by intelligent system design. A change in philosophy away from studying pathways in isolation and towards studying metabolism as a network is necessary. To support this development, improvements in technologies for metabolic analysis, a wider adoption of metabolite-profiling approaches and significant innovations in data analysis methodologies are required.     

Peroxomanganese complexes as an aid to understanding redox-active manganese enzymes

Over the past 7 years, there have been a significant number of studies describing the structural and electronic properties, as well as the chemical reactivity, of synthetic peroxomanganese adducts. Many redox-active manganese enzymes, including manganese-containing superoxide dismutases, extradiol catechol dioxygenases, and ribonucleotide reductases, are proposed to feature peroxomanganese intermediates in their catalytic cycles. The recent efforts to model these intermediates using synthetic complexes have thus provided a strong complement to mechanistic studies of the enzymes. This review provides both a summary and a perspective of work in this area, with an emphasis on the relationship between geometric and electronic structure and chemical reactivity for η²-peroxomanganese(III) and η¹-alkylperoxomanganese(III) adducts.     

Biochemical tests as an aid to the identification of Monascus species

The enzymic activity of nine strains of Monascus (Fungi, Ascomycotina), representing all four accepted species as defined on cultural and microscopical features, were compared by means of API ZYM enzyme testing strips and other tests developed for use in Penicillium. Consistent results were obtained between strains of the same species, confirming their taxonomy. Eight tests showed differential activity between the species and will therefore be of value as an aid to the identification of Monascus species. Strains of M. purpureus , used in the production of red-rice, had a strong polypectase activity at pH 6 which was not evidenced in the other three species even after six weeks incubation; those of M. ruber , which often occurs on cellulosic substrates in nature, were the only ones to exhibit cellulase activity.     

A Simple Method for Staining Nuclei of Mature and Germinated Maize Pollen

A sugar acetocannine staining technique has been developed for staining the sperm and vegetative nucleus of mature and germinated maize pollen grains. This procedure is simple, stable and highly repeatable. The physiological properties of the mature maize pollen grains are first adjusted by using an in vitro germinating culture solution. This solution is 15% sucrose and contains 360 ppm calcium chloride dihydrate, and 120 ppm boric acid. One part fresh pollen grains is uniformly mixed with nine parts of the solution and left at room temperature for at least 5 hr. One part of this solution is then mixed with two parts of regular acetocannine stain and left overnight. The color of this mixture is pinkish red or raspberry. The sugar in the mixture helps to increase color contrast between the pollen cytoplasm (light pink) and the nuclei (reddish purple), decreases the frequency of burst pollen, increases pollen expansion, stabilizes pollen figures and automatically seals the coverglass.