Gene expression profiles in dendritic cells conditioned by 1alpha,25-dihydroxyvitamin D3 analog

Inhibition of dendritic cell (DC) maturity is an important immunomodulatory effect of 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) and related analogs (D(3) analogs). The mechanisms underlying 1alpha,25(OH)(2)D(3)-mediated DC modulation are Vitamin D receptor (VDR)-dependent and likely involve direct or indirect regulation of multiple genes. Gene expression profiles of bone marrow-derived DCs (BMDCs) generated in the absence or presence of a potent D(3) analog were analyzed using microarray technology. Results for D(3) analog-conditioned DCs were also compared with glucocorticoid-conditioned BMDCs and with BMDCs conditioned with D(3) analog and glucocorticoid combined. Of approximately 12,000 gene products assayed, 52% were considered to have detectable expression in unconditioned BMDCs. Based on relative expression levels, 5.3% of these expressed genes were "silenced" or "suppressed" in D(3) analog-conditioned BMDCs and 2.1% were "augmented". In addition, 1.7% of gene products undetectable in control BMDCs were "induced" by D(3) analog. Functional grouping of modulated genes demonstrated important effects of D(3) analog on immunoreceptors, on chemokines and chemokine receptors, on growth factors/cytokines and related receptors, and on neuroendocrine hormones and related receptors. Many of these gene products were unaffected or differently regulated by glucocorticoid suggesting specific VDR-mediated regulatory effects. Confirmation of microarray analysis results for two differentially regulated chemokines (MIP-1alpha and RANTES) was obtained by RT-PCR and ELISA. The methodology provides novel insights into DC gene regulation by 1alpha,25(OH)(2)D(3) agonists.     

Isolation and characterization of the tobramycin biosynthetic gene cluster from Streptomyces tenebrarius

The biosynthetic gene cluster for tobramycin, a 2-deoxystreptamine-containing aminoglycoside antibiotic, was isolated from Streptomyces tenebrarius ATCC 17920. A genomic library of S. tenebrarius was constructed, and a cosmid, pST51, was isolated by the probes based on the core regions of 2-deoxy-scyllo-inosose (DOI) synthase, and L-glutamine:DOI aminotransferase and L-glutamine:scyllo-inosose aminotransferase. Sequencing of 33.9 kb revealed 24 open reading frames (ORFs) including putative tobramycin biosynthetic genes. We demonstrated that one of these ORFs, tbmA, encodes DOI synthase by in vitro enzyme assay of the purified protein. The catalytic residues of TbmA and dehydroquinate synthase were studied by homology modeling. The gene cluster found is likely to be involved in the biosynthesis of tobramycin.     

Somatic embryogenesis in <Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.: a histological examination of key developmental stages

A potential novel method of producing high-quality potato (Solanum tuberosum L.) nuclear seeds is through the process of somatic embryogenesis (SE). Somatic embryo formation has been successfully reported in many plant species, but in potato, reliable SE systems are still at the experimental stage. A key factor in the success of any SE system is the ability to discriminate SE-specific cellular structures from those emerging through an organogenic route. In the investigation reported here we attempted to discriminate the progression of specific stages of potato SE by histological means. Internodal segment (INS) explants from 4- to 6-week-old cv. Desiree in vitro cultures were successively cultured on SE induction (for 2 weeks) and expression/regeneration media (for 3 weeks) with and without 2,4-dichlorophenoxyacetic acid (5 M). Microscopic examination of histological slides prepared using INS explants at different stages revealed the presence of characteristic globular, heart and torpedo stages in the potato SE system along with other associated unique features such as protoderm development and discrete vascular connections. These results confirm the occurrence of potato SE as per the accepted definition of the term.Abbreviations 2,4-D 2,4-Dichlorophenoxyacetic acid - ELS Embryo-like structure(s) - INS Internodal segment(s) - PEM Proembryo mass - SE Somatic embryogenesis     

Deoxypreussomerins from Jatropha curcas: are they also plant metabolites?

Three deoxypreussomerins, palmarumycins CP1, JC1 and JC2, have been isolated from a collection of the stems of Jatropha curcas. The second and third compounds are antibacterial constituents which were characterized from spectral evidence. The X-ray crystallographic structure of palmarumycin JC1 was also studied. Deoxypreussomerins have been obtained here from a plant source in appreciable quantities.     

The role of adapter protein Shc in estrogen non-genomic action

Breast cancer is one of the most common malignancies in the United States. Seventy percent of breast cancers are hormone-responsive due to the presence of estrogen receptors ERalpha and ERbeta, which are important diagnostic and therapeutic targets in cancer treatment. Estrogen acts through its receptors, which reside on the cell membrane as demonstrated recently and in the nucleus, leading to cancer cell proliferation and protection from cell death. The membrane ERalpha has been reported in MCF-7 human breast cancer cells and is believed to mediate estrogen effects to activate mitogen-activated protein (MAP) kinase and phosphoinositide 3-kinase (PI3-kinase). Activation of many growth factor receptors require adapter proteins to delivery the upstream signals to downstream kinases, such as MAP kinase. Both Shc and the p85alpha subunit of PI3-kinase are adapter proteins. In addition to their roles in transducing signals from membrane growth factor receptors, they have been demonstrated to interact with ERalpha in an estrogen dependent manner. In this review, the role of Shc in mediating estrogen effects on MAP Kinase regulation, cell growth and anti-apoptosis will be discussed. The possible role of PI3-kinase in estrogen rapid action is also reviewed in brief.     

Suggestive evidence of association of C-159T functional polymorphism of the <Emphasis Type="Italic">CD14</Emphasis> gene with atopic asthma in northern and northwestern Indian populations

CD14 is a lipopolysaccharide receptor known to be an important modulator of Th1–Th2 response during early childhood. Genetic association studies of the CD14 gene with asthma and atopic disorders have shown positive as well as negative results in different ethnic populations. The aim of this study was to test for association of C-159T functional promoter polymorphism with atopic asthma and serum IgE levels in northern and northwestern Indian populations. DNA was assayed for the CD14 C-159T polymorphism in a case-control study involving atopic asthmatics (n=187) and healthy normal controls (n=227), and in a family-based association study of 106 trios. The case-control study showed an association at the genotypic (P=0.0146) as well as the allelic level (P=0.0048). Moreover, we observed a deviation of allelic transmission from random proportions (P=0.024) in the transmission disequilibrium test analysis. When we analyzed our results for serum total IgE levels, against this polymorphism, we observed a difference at the genotypic (P=0.0026) as well as at the allelic level (P=0.0016) in a case-control study, whereas no association in the quantitative transmission disequilibrium test analysis was obtained. These findings provide suggestive evidence of association of the CD14 gene locus with atopic asthma in northern and northwestern Indian populations.     

Biosensor based on Langmuir–Blodgett films of poly(3-hexyl thiophene) for detection of galactose in human blood

An amperometric biosensor was developed to estimate galactose in human blood serum. Monolayers of poly(3-hexyl thiophene) were placed on glass plates coated with indium tin oxide formed by dispensing a mixed solution of stearic acid in chloroform on to a water sub-phase. Galactose oxidase was mixed with poly(3-hexyl thiophene)/stearic acid in chloroform and dispensed on to the air-water interface of Langmuir-Blodgett trough. These monolayers were transferred on to glass plates which were used as working electrodes with platinum as a reference electrode. The amperometric galactose biosensor thus fabricated had a linear response from 0.05 to 0.5 g galactose l(-1) in blood serum. The normal level in blood is < 0.05 g galactose l(-1) in adults and 0-0.2 g galactose l(-1) in infants. In case of galactosemia, this increases to above 0.2 g galactose l(-1) in infants.