RAPD typing for distinguishing species and strains in the genus Listeria

The randomly amplified polymorphic DNA (RAPD) technique was employed in the development of a typing protocol for Listeria isolates, particularly Listeria monocytogenes strains. A single strain of L. monocytogenes was used and 200 random decamer primers were screened for their discriminatory abilities by visualizing the amplification products electrophoretically. Three candidate primers displaying potentially useful banding patterns were selected and tested against 52 L. monocytogenes strains, encompassing 11 serotypes, and 12 other strains representing five other Listeria spp. Thirty-four banding profiles were obtained with one particular primer. RAPD analysis allowed differentiation between Listeria spp. and was found to further subdivide strains of the same serotype. Where only one primer was used strains from different serotypes were occasionally found to produce identical banding profiles. RAPD analysis, which in our hands proved to be reproducible, shows much promise as a molecular alternative to traditional L. monocytogenes typing protocols.     

Enzyme histochemical characteristics of human and kitten odontoclasts and kitten osteoclasts: a comparative study using whole cells

Synopsis Methods for the histochemical demonstration of enzymes in whole cell preparations of odontoclasts and osteoclasts are described. Enzyme histochemical characteristics of human and kitten odontoclasts from resorbing primary teeth and of osteoclasts from kitten femur metaphyses were determined and compared. The enzyme profiles, times for the appearance of detectable reaction product, intensity of the reactions and localization of the reaction products were similar in all three types of giant cell. These findings suggest that odontoclasts have enzyme properties and metabolic functions similar to those of osteoclasts. Species differences appear to be minor, although the NADP-dependent enzymes are less active in human than in kitten odontoclasts. Both odontoclasts and osteoclasts are rich in enzymes concerned with energy production and possess considerable activity of enzymes usually associated with catabolic functions. Metabolic pathways are well developed in respect of the utilization of succinic, malic, glutamic, lactic and isocitric acids, -hydroxybutyric acid and glucose-6-phosphate, and they also possess phosphatases, non-specific esterases and leucine naphthylamidase. The distribution of enzyme reaction products for the individual enzymes demonstrated is consistent with the presence in these cells of large numbers of mitochondria and lysosome-like organelles. Considerable phosphatase activity is demonstrable in both odontoclasts and osteoclasts at both neutral and acid pH.     

The purification and properties of valine tRNAs of Drosophila melanogaster.

The valine transfer ribonucleic acids of Drosophila melanogaster have been purified by column chromatography on BD-cellulose, Sepharose 6B, and RPC-5. Three major species were analyzed for base composition and coding properties. Valyl-tRNAVal3a binds strongly to ribosomes in the presence of GUA and to a lesser extent with GUU and GUG. Valyl-tRNAVal3b binds strongly in the presence of GUG and very poorly if at all with the other three triplets whereas valvyl-tRNAVal4, which contains inosine, binds strongly in the presence of GUU, GUC, and GUA and weakly with GUG.     

Liver hypertrophy in winter flounder following exposure to experimentally oiled sediments

1. Male winter flounder were exposed to sediments contaminated with Venezuelan crude oil in 3 laboratory experiments of 4-5 months duration. 2. Oil exposure resulted in significant increases in liver weight. This was particularly evident in fish weighing less than 400 g. 3. The enlarged livers of the oil-exposed flounder had reduced concentrations of DNA, protein, Na+ and Zn2+, and increased concentrations of lipid and phospholipid. 4. The reduced DNA and Na+ concentrations suggested liver hypertrophy rather than hyperplasia. 5. The increased phospholipid concentrations suggested growth of membrane structures such as endoplasmic reticulum.     

Genomic organization of the rat α2u-globulin gene cluster

The α_2u-globulins are a group of similar proteins, belonging to the lipocalin superfamily of proteins, that are synthesized in a subset of secretory tissues in rats. The many α_2u-globulin isoforms are encoded by a multigene family that exhibits extensive homology. Despite a high degree of sequence identity, individual family members show diverse expression patterns involving complex hormonal, tissue-specific, and developmental regulation. Analysis suggests that there are approximately 20 α_2u-globulin genes in the rat genome. We have used fluorescence in situ hybridization (FISH) to show that the α_2u-globulin genes are clustered at a single site on rat Chromosome (Chr) 5 (5q22-24). Southern blots of rat genomic DNA separated by pulsed field gel electrophoresis indicated that the α_2u-globulin genes are contained on two NruI fragments with a total size of 880 kbp. Analysis of three P1 clones containing α_2u-globulin genes indicated that the α_2u-globulin genes are tandemly arranged in a head-to-tail fashion. The organization of the α_2u-globulin genes in the rat as a tandem array of single genes differs from the homologous major urinary protein genes in the mouse, which are organized as tandem arrays of divergently oriented gene pairs. The structure of these gene clusters may have consequences for the proposed function, as a pheromone transporter, for the protein products encoded by these genes. Received: 12 August 1998 / Accepted: 13 January 1999     

Autosomal STR variation in five Austronesian populations

Human population characteristics at the genetic level are integral to both forensic biology and population genetics. This study evaluates biparental microsatellite markers in five Austronesian-speaking groups to characterize their intra- and interpopulation differences. Genetic diversity was analyzed using 15 short tandem repeat (STR) loci from 338 unrelated individuals from 5 Pacific islands populations, including the aboriginal Ami and Atayal groups from Taiwan, Bali and Java in Indonesia, and the Polynesian islands of Samoa. Allele frequencies from the STR profiles were determined and compared to other geographically targeted worldwide populations procured from recent literature. Hierarchical AMOVA analysis revealed a large number of loci that exhibit significant correspondence to linguistic partitioning among groups of populations. A pronounced divide exists between Samoa and the East (Formosa) and Southeast Asian (Bali and Java) islands. This is clearly illustrated in the topology of the neighbor-joining tree. Phylogenetic analyses also indicate clear distinctions between the Ami and Atayal and between Java and Bali, which belie the respective geographic proximities of the populations in each set. This differentiation is supported by the higher interpopulation variance components of the Austronesian populations compared to other Asian non-Austronesian groups. Our phylogenetic data indicate that, despite their linguistic commonalities, these five groups are genetically distinct. This degree of genetic differentiation justifies the creation of population-specific databases for human identification.     

Echinacea alkamide disposition and pharmacokinetics in humans after tablet ingestion

Echinacea is a widely used herbal remedy for the treatment of colds and other infections. However, almost nothing is known about the disposition and pharmacokinetics of any of its components, particularly the alkamides and caffeic acid conjugates which are thought to be the active phytochemicals. In this investigation, we have examined serial plasma samples from 9 healthy volunteers who ingested echinacea tablets manufactured from ethanolic liquid extracts of Echinacea angustifolia and Echinacea purpurea immediately after a standard high fat breakfast. Caffeic acid conjugates could not be identified in any plasma sample at any time after tablet ingestion. Alkamides were rapidly absorbed and were measurable in plasma 20 min after tablet ingestion and remained detectable for up to 12 h. Concentration-time curves for 2,4-diene and 2-ene alkamides were determined. The maximal concentrations for the sum of alkamides in human plasma were reached within 2.3 h post ingestion and averaged 336+/-131 ng eq/mL plasma. No obvious differences were observed in the pharmacokinetics of individual or total alkamides in 2 additional fasted subjects who took the same dose of the echinacea preparation. This single dose study provides evidence that alkamides are orally available and that their pharmacokinetics are in agreement with the one dose three times daily regimen already recommended for echinacea.