Separation of finasteride and analogues

This review is focused on the different chromatographic strategies for determination of finasteride and its analogues in biological fluids. These compounds are used for the treatment of benign prostatic hyperplasia. Particular attention is paid to high-performance liquid chromatography with spectrophotometric and mass spectrometric detection, the clean-up procedures are also included. The relationships between pharmacokinetics of finasteride, dose administered and required limit of quantitation of the chromatographic assays are discussed. Tandem mass spectrometry is recommended as the detection method for measuring concentrations <1 ng/ml, while cheaper spectrophotometric detection may be selected for determination of higher concentrations.     

Evolution of sprouting versus seeding inAspalathus linearis

We have tested the hypothesis that reseeding is a plesiomorphic character state and that sprouting is a derived state inAspalathus linearis, and that the latter is an adaptation to ensure fire-survival in a fireprone environment. Samples of five seeder and four sprouter populations of A.linearis were examined by horizontal starch gel electrophoresis to assess the amount of genetic differentiation within and between sprouting and seeding populations, and to determine the extent of gene flow between the populations. Leaf extracts were surveyed for ten enzymes and gene products revealed genetic variation at 13 (76%) of 17 protein coding loci. Allele frequency differences were found between sprouting and seeding populations and genetic distance values show that the sprouters are grouped separate from the seeders, thus providing support for the morphological data on which the above mentioned hypothesis is based. It is evident that evolution operates at the population level inA. linearis.     

Mutagenesis of hydroxylamine oxidoreductase in Nitrosomonas europaea by transformation and recombination.

Mutagenesis of Nitrosomonas europaea was achieved by electroporation and recombination. To demonstrate this, an aminoglycoside 3'-phosphotransferase (kan) gene was specifically inserted into each of the three gene copies of hao individually. Southern hybridizations and PCR analysis showed the incorporation of the kan gene at the chosen genetic loci. The isolation of mutant strains was achieved in 7 to 14 days when the strains were grown on solid medium. The induced mutations were stable even in the absence of kanamycin-selective pressure for periods of up to 45 days in culture. The mutant strains did not show an observable phenotype different from that of the wild type when grown under the same conditions.     

The occurrence and frequency of 2n pollen in 2x, 4x,and 6x wild,tuber-bearing Solanum species from Mexico,and Central and South America

Summary The occurrence of 2n pollen-producing plants was investigated in 187 plant introductions (PIs) of 38 wild species of tuber-bearing Solanum. These 2x, 4x, and 6x species are from Mexico, and Central and South America. The determination of 2n pollen-producing plants was conducted using acetocarmine glycerol. Plants with more than 1% large-size pollen were regarded as 2n pollen-producing plants. 2n pollen-producing plants were identified in the following species: 10 out of 12 Mexican 2x species, seven of nine South American 2x species, seven of seven Mexican and Central American 4x species, five of five South American 4x species, and five of five Mexican 6x species. The frequency of 2n pollen-producing plants varied among species at the same ploidy level, but the range of frequency, generally between 2 and 10% among species, was similar over different ploidy levels. The general occurrence of 2n pollen in both 2x and polyploid species, which are evolutionarily related, is evidence that the mode of polyploidization in tuber-bearing Solanums is sexual polyploidization. Furthermore, the frequencies of 2n pollen-producing plants in autogamous disomic polyploid species were not markably different from those of their related diploid species. It is thought that the frequent occurrence of 2n gametes with autogamy tends to disturb the fertility and consequently reduce fitness of polyploids. Thus, we propose that the breeding behavior of polyploids and the occurrence of 2n gametes may be genetically balanced in order to conserve high fitness in polyploid species in tuberbearing Solanum.Paper No. 3114 from the Laboratory of Genetics. Research supported by the College of Agriculture and Life Sciences; International Potato Center; USDA, SEA, CGRO 84-CRCR-1-1389; and Frito Lay, Inc.     

Evidence for the expression of two distinct MHC class II DRβ like molecules in the sheep

This study used monoclonal antibodies to sheep MHC class II molecules as well as an L cell transfectant (T8.1) which expresses DRA and DRB genes to show that two distinct DRβ chains are expressed in the sheep. Two anti-β chain specific monoclonal antibodies VPM37 and VPM43 react with DR antigen but not DQ antigen by ELISA. These two antibodies do not react with the DRβ chain expressed in the T8.1 cell line. Two-dimensional immunoblotting shows that these antibodies recognize a subgroup of the spots recognized by the DR-specific monoclonal antibody VPM57 which does react with the T8.1 β chain. Amino-terminal sequence analysis of the α chain associated with VPM37β chain shows that this α chain is homologous to the human DRα chain strongly indicating that the β chain is DR-like. VPM37 and VPM43 are shown to be directed against different epitopes on sheep MHC class II molecules so it is highly unlikely that the data can be explained by the presence of posttranslational modifications or the existence of a very common allele. These data provide clear evidence for the expression of two distinct DRP chains in the sheep.     

Retrograde Traffic Out of the Yeast Vacuole to the TGN Occurs via the Prevacuolar/Endosomal Compartment

A large number of trafficking steps occur between the last compartment of the Golgi apparatus (TGN) and the vacuole of the yeast Saccharomyces cerevisiae. To date, two intracellular routes from the TGN to the vacuole have been identified. Carboxypeptidase Y (CPY) travels through a prevacuolar/endosomal compartment (PVC), and subsequently on to the vacuole, while alkaline phosphatase (ALP) bypasses this compartment to reach the same organelle. Proteins resident to the TGN achieve their localization despite a continuous flux of traffic by continually being retrieved from the distal PVC by virtue of an aromatic amino acid–containing sorting motif. In this study we report that a hybrid protein based on ALP and containing this retrieval motif reaches the PVC not by following the CPY sorting pathway, but instead by signal-dependent retrograde transport from the vacuole, an organelle previously thought of as a terminal compartment. In addition, we show that a mutation in VAC7, a gene previously identified as being required for vacuolar inheritance, blocks this trafficking step. Finally we show that Vti1p, a v-SNARE required for the delivery of both CPY and ALP to the vacuole, uses retrograde transport out of the vacuole as part of its normal cellular itinerary.     

Impact of the TCR Signal on Regulatory T Cell Homeostasis,Function, and Trafficking

Signaling through the T cell antigen receptor (TCR) is important for the homeostasis of naïve and memory CD4⁺ T cells. The significance of TCR signaling in regulatory T (Treg) cells has not been systematically addressed. Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional null allele of the gene encoding p56^Lck, we have examined the importance of TCR signaling in Treg cells. Inactivation of p56^Lck resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression. Abnormal Treg cell homeostasis and function did not reflect the involvement of p56^Lck in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR.