Monospecific antibodies against a synthetic peptide predicted from the alpha-3 nicotinic receptor cDNA inhibit binding of [3H]nicotine to rat brain nicotinic cholinergic receptor

Polyclonal antibodies were raised against a synthetic decapeptide (designated S3) predicted from a segment of the alpha-3 subunit cDNA (amino acid residues 130-139) encoding the rat brain nicotinic cholinergic receptor. This segment was selected because it may be proximate to the nicotine/acetylcholine-binding site of the receptor (1). By radioligand binding assays and sucrose density gradient centrifugation, these monospecific antibodies were shown to inhibit the binding of [3H]nicotine to both the large molecular weight rat brain receptor (240 kDa) and to an SDS-disaggregated nicotine-binding subunit species (80 kDa), in a dose-dependent manner. The neutralizing effect of the anti-S3 antibodies supports the view that this region of the protein is closely related to the agonist binding site.     

A partial map of the barley genome incorporating restriction fragment length polymorphism, polymerase chain reaction, isozyme, and morphological marker loci

Nine low copy number genomic DNA clones, a ribosomal sequence, and seven cDNA clones were found to identify polymorphisms in cultivated barley (Hordeum vulgare L.). An F2 population consisting of 100 plants was produced from a cross between a high-yielding two-rowed feed barley cultivar and a genetic marker stock homozygous for nine recessive and one dominant morphological marker genes. Through the use of these 10 well-distributed marker genes, five previously mapped isozyme loci, and two storage-protein loci, the approximate recombinational location for each of 17 restriction fragment length polymorphism loci was estimated. One clone, pMSU21, identified variation that appeared to be the result of a small insertion-deletion event that differentiated two-rowed and six-rowed genotypes. This difference was characterized, and one allele was sequenced. Oligonucleotide primers that flanked the insertion-deletion event were synthesized, and DNA samples from the F2 population were subjected to polymerase chain reaction sequence amplification. The variation identified by this technique was determined to be allelic to the variation identified using pMSU21 in Southern blot analysis. Maps of previously undescribed informative clones are included.     

Investigation of dye/protein interaction and its application to enzyme purification

In this review the results of the interaction of the active dyes used in the USSR textile industry with microbial enzymes and blood serum proteins are discussed. The complexity of dye/protein interaction and the dependence of this interaction on different factors is demonstrated. Some practical aspects of the use of dye containing sorbents are presented and discussed. Their suitability for RNA ligase and DNA ligase, acetate kinase, alcohol dehydrogenase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase purification and blood serum protein fractionation is demonstrated.     

Degradation of diarylethane structures by Pseudomonas fluorescens biovar I

Pseudomonas fluorescens biovar I was isolated from a pulp mill effluent based on its ability to grow on synthetic media containing 1,2-diarylethane structures as the sole carbon and energy source. Analysis of samples taken from cultures of this strain in benzoin or 4,4-dimethoxybenzoin (anisoin), showed that cleavage between the two aliphatic carbons takes place prior to ring fission. Intermonomeric cleavage was also obtained with crude extracts. Substrates of this reaction were only those 1,2-diarylethane compounds that supported growth of the bacterium. The purification and partial characterization of an enzyme that catalyzes the NADH-dependent reduction of the carbonyl group of benzoin and anisoin is also reported.     

Asymmetric incorporation of [14C]cyanate and of fluorescein isothiocyanate in mamillary body of conditioned rats

A marked decrease in overall learning capacity has been observed in rats injected with cyanate. Therefore it was of interest to test whether learning influenced carbamylation of brain proteins. Incorporation of [¹⁴C]cyanate into proteins of the mamillary body was selectively modified following operant conditioning of the rat, so that trained rats showed an asymmetric image with higher levels of incorporation in the right side than in the left side, as compared to control rats. These results were confirmed using fluorescein isothiocyanate. The asymmetry persisted once the learning had been well established.     

Chromium in plants

Chromium is an essential trace element and is associated with some biological pathways, especially with glucose tolerance. For these reasons, we decided to determine the concentration of chromium in two sets of Brazilian medicinal plants. The first group consisted of plants that are considered as antidiabetic, whereas the second included plants that do not have this therapeutic property. The concentration of chromium was determined by flameless atomic absorption. All the plants analyzed contain chromium in the normal range for this element, but the hypoglycemic plants contain more chromium than the others (1–4 μg/g compared to 0.5–1.5 μg/g).     

Effects of traces of rare earth elements on the protozoanBlepherisma and on mice

The growth of the protozoanBlepherisma is stimulated by Lanthanum (La) at concentrations as low as 0.32 ppm. In mice Yttrium (Y) and Ytterbium (Yb) are absorbed, accumulated, and metabolized. Both rare earth elements (RE) exhibit a high affinity for teeth and bones, accumulation occurs and metabolism is slow. In the livers of RE-exposed mice, concentrations are variable. The liver is apparently capable of absorbing and discharging RE in a manner depending on metabolic activity. The main route of discharge for ingested REs is the alimentary canal. Exposure of pregnant mice to RE leads to rapid placental transfer of RE; 14.1% of the total amount of RE administered was detected in newborn mice. Young, developing organisms appear to be especially susceptible to RE accumulation.     

Ultrastructure of the mitotic nuclei in Leishmania mexicana ssp. Tridimensional reconstruction of the mitotic spindle and dense plaques

The ultrastructure of mitotic nuclei of the promastigote Leishmania mexicana ssp. was studied by serial thin sections and three-dimensional reconstructions of each divisional stage. At the beginning of nuclear division (equatorial stage), a set of six dense plaques located about the equatorial region of the nucleus and a microtubular spindle develops in the two opposing poles of the nucleus (two sets of polar microtubules). The microtubular mitotic spindle is entirely intranuclear with the nuclear membrane persisting through mitosis. The polar spindle consists of a discrete bundle of about 50 microtubules and the equatorial spindle is formed by about 100 microtubules. The spindle may contain several continuous microtubules, but no microtubular organizing centres were observed in association with the spindle. The plaques and hemiplaques are associated with microtubular bundles; some of the spindle microtubules converge on kinetochore-like plaques. It is suggested that the spindle has a special significance in the physiology of mitosis. The two sets of hemiplaques may guide the separation of the daughter genomes. At the beginning of the elongational stage the mitotic plaques split into halves and each set of half-plaques migrates to one pole. It is concluded that the dense plaques play a kinetochore-like role and thus Leishmania mexicana ssp. may have six chromosomal units. Mitotic events of this species are essentially similar to those of Trypanosoma cruzi.     

Extramacrochaetae,a trans-acting gene of the achaete-scute complex of Drosophila involved in cell communication

Summary Phenotypic analyses of genetic combinations involving the gene extramacrochaetae (emc) reveal its participation in the differentiation of both sensory elements and wing veins. The study of near-amorphic alleles of emc in mitotitc recombination clones indicates that it also affects cell proliferation. These clones show abnormal sizes, shapes and spatial distribution. They differentiate extra sensory elements as well as extra veins. A gain of function mutation in the gene causes opposite phenotypes in both differentiation systems. The effects of the mutant on proliferation and patterning are consistent with the emc gene being involved in the transfer of information between neighbouring cells, which leads to the spatial expression of the achaetescute gene complex and genes involved in vein formation.