A simple and rapid technique for assaying toxicants in aphids

A simple bioassay technique has been developed in order to study the effect of toxic compounds on aphids. The technique involves dipping of leaves of a particular aphid host in a solution of the desired toxic compound contained in a vacuum flask. The flask is then connected to a vacuum source in order to remove the air from the intercellular spaces of the palisade and the spongy parenchymas of the leaves. Breakage of the vacuum and return to atmospheric pressure forces the test solution into the now empty intercellular spaces which are thus filled with the solution. The treated leaves exhibited a typical water-soaked appearance. The infiltrated leaves were then offered to the aphids. The above treatment did not affect either the structure of the leaves or the development of the aphid colony on them. Aphids grown on leaves infiltrated with water lived longer in comparison with controls. In addition, insects grown on leaves infiltrated with 27.5, 13.7 and 6.9 p.p.m. of the systemic insecticide heptenophos died after 1.5, 3.0 and 5.0 h, respectively. The bioassay technique described in this report has certain advantages: it is simple, fast and inexpensive and is especially suitable for short-term studies involving the effects of such chemicals as toxins, insecticides and other toxicants on aphids. It may also be used to study the effects of growth factors, hormones and special nutrients on aphid growth and possibly on other sucking insects.     

A simple and rapid technique for fluorescence staining of fungal nuclei

A technique for staining fungal nuclei using fluorescence stain Hoechst Dye 33258 in McIlvaine standard buffer of pH 7.26–7.44 is reported. It is a broad-spectrum fungal nuclear staining tool found to be effective onAgaricus bisporus, Alternaria helianthi, Fusarium oxysporum f. sp.lini, Penicillium binellum, Pythium ultimum, Rhizoctonia solani, andSaccharomyces cerevisiae. Conidial nuclei ofAlternaria helianthi, Fusarium oxysporum f. sp.lini, andPenicillium binellum also stained well.     

A simple and rapid method for determining the linearity of a flow cytometer amplification system

We describe a simple and rapid method for determining the linearity of a flow cytometer amplification system. The method is based on a fundamental characteristic of linear amplifiers: The difference between two amplified signals increases linearly with increasing amplifier gain. Two populations of beads or cells, differing slightly in fluorescence intensity, are analyzed by the flow cytometer at increasing photomultiplier tube high-voltage settings. The distribution of the populations' mean difference versus mean position is a straight line intersecting the origin for linear amplifiers. Although some types of nonlinearities cannot be detected with this technique, deviations from linearity indicate nonlinear components in the flow cytometer amplification system. The correlation coefficient is used to quantify degree of nonlinearity. We also describe a method for amplifier nonlinearity compensation.     

A simple and rapid purification of kallikrein from rat submandibular gland.

Rat submandibular kallikrein was isolated in an 87% yield by a very quick and simple procedure involving hydrophobic interaction chromatography. Furthermore, that purification method was superior to both aprotinin-affinity chromatography and immunoaffinity chromatography for the purification of rat submandibular kallikrein. The kallikrein purified by hydrophobic interaction chromatography consisted of a number of isoenzymes. The major component of Mr 38,000 seen on SDS-gel electrophoresis was found to be the glycosylated kallikrein, whereas the minor component of Mr 26,000 represented the non-glycosylated enzyme.     

A rapid and simple method for the purification of rat liver RNase inhibitor

A rapid and simple method for the purification of rat liver alkaline RNase inhibitor from a 105,000 g supernatant is reported. It involves protein precipitations by (NH₄)₂SO₄ and chromatography on carboxymethyl cellulose-RNase column. The purification procedure gives a 1020-fold increase in specific activity with a yield of 32%. This purified inhibitor can be stored for 5 weeks without any loss in activity.     

A rapid and simple screening technique for potential crude oil degrading microorganisms

Summary A rapid and simple technique has been developed for screening potential crude oil degrading bacteria using the redox indicator 2,6-dichlorophenol indophenol in Bushnell and Haas medium with crude oil and a microtitre plate. Bacteria possessing high crude oil degrading potential turn the medium colourless after 24 h incubation but, depending upon the time taken for the change in colour, relative abilities of different cultures can be ascertained.     

A single cannula technique for nonsurgical collection of ova from cattle.

The uteri of 34 heifers were flushed for ova six to nine days following estrus using a single cannula nonsurgical technique. The technique involved the infusion of fluid by gravity and agitation within the uterus by to-and-fro action of a syringe followed by unassisted fluid collection. Each horn was flushed five times using 30–150 ml of flushing fluid per flush. Recovered fluid (flushing fluid plus uterine secretion) was an average of 95% of the volume of the fluid inserted. Ova were recovered from 12 of 19 nontreated, single ovulating heifers (63%) and from all of 15 superovulated heifers (mean and S.D. for number of ova, 6.3 ± 4.4/ superovulated heifer; range, 1 to 14 ova). Based on the number of corpora lutea, the ova recovery index was 54% as averaged over the 15 superovulated heifers. The technique has been used in 4 additional superovulated heifers with modification (increased number of flushes to 8) subsequent to the termination of the planned project. Recovery index for the first 5 flushes was 58%. However, some ova were recovered in the 6th, 7th, and 8th flushes resulting in an apparent improved recovery index of 69%.     

A simple fluorescence staining technique for the differentiation of human tissue transplanted into nude mice.

Human and mouse nuclei can be distinguished by differences in the constitutive heterochromatin when stained with quinacrine dihydrochloride. With the staining method described, mouse heterochromatin during interphase appears as brilliant fluorescent chromocenters. By replacing the commonly used aqueous buffer mounting medium with a xylene-diluted synthetic resin, the haziness of the nuclear fluorescence is eliminated thus allowing identification of the heterochromatin pattern in histological preparations. A requirement for the definite identification of cells of human or murine origin in the nude mouse is the knowledge that the heterochromatin arrangements changes according to the stage of differentiation of the cell of the position of a particular nucleus within the cell cycle.     

A simple autoradiographic technique for studying diffusion of water into seeds

Visual observations on rates and modes of water penetration into black bean seeds and into wheat and sorghum kernels during conditioning were accomplished by an autoradiographic procedure that eliminates a freezing microtome and liquid and stripping film emulsions. Seeds soaked in tritiated H₂O were hand sectioned before freeze-quenching in liquid N₂ and subsequent block autoradiography on nuclear medicine film.     

A new, rapid and simple procedure for direct cloning of PCR products into baculoviruses.

We propose a novel method for direct cloning of foreign genes into baculoviruses which avoids the use of bacterial transfer vectors. The foreign gene to be inserted is derived by PCR using appropriate primers each of which contains an additional 50 nt of baculovirus sequence for homologous recombination between the PCR-derived DNA and the baculovirus DNA, thus accomplishing insertion of the foreign gene into the baculovirus. The direct cloning of green fluorescent protein and beta-glucuronidase in different baculovirus loci is described. The method is simple and avoids the use of cumbersome techniques associated with enzymatic treatment and DNA purification.