Effect of drugs and temperature on biosynthesis and transport of glycosphingolipids in cultured neurotumor cells

Neuroblastoma and glioma cells were grown in the presence of [³H]galactose, and the incorporation of ³H into gangliosides and the transport of newly synthesized gangliosides to the cell surface were examined under different experimental conditions. A variety of drugs, including inhibitors of protein synthesis and energy metabolism, modulators of the cytoskeleton and the ionophore monensin, had no effect on the transport of newly synthesized GD1a in neuroblastoma cells. Only low temperature effectively blocked translocation to the plasma membrane. Monensin, however, had marked effects on the biosynthesis of gangliosides and neutral glycosphingolipids. Whereas incorporation of ³H into complex glycosphingolipids was reduced, labeling of glucosylceramide was increased in cells exposed to monensin. In addition, biosynthesis of the latter glycolipid was less susceptible to low temperatures than that of more complex ones. Previous studies have implicated the Golgi apparatus as the predominant site of glycosylation of gangliosides. As monensin has been reported to interfere with the Golgi apparatus, our results indicate that glucosylceramide may be synthesized at a site that is separate from the site where further glycosylation occurs. Once synthesis of a ganglioside is completed, transport of the molecule to the cell surface proceeds under conditions of cytoskeletal disruption, energy depletion and ionic inbalance, but not low temperature.     

Biotransformation of hydroquinone to arbutin in plant <Emphasis Type="Italic">in vitro</Emphasis> cultures — preliminary results

Cells from Echinacea purpurea (L.) Moench. (Asteraceae), Exacum affine Balf. f. (Gentianaceae), Melittis melissophyllum L. (Lamiaceae), Ruta graveolens L. and Ruta graveolens ssp. divaricata (Tenore) Gams. (Rutaceae) agitating cultures perform a biotransformation reaction on exogenously supplied hydroquinone into its β-D-glucoside — arbutin, product with valuable medicinal and cosmetic properties. The maximum content of arbutin (determined by HPLC) in the biomass from investigated cultures is 4.01; 3.44; 1.79; 2.48 and 5.07 g/100 g d.w., respectively. Nothing but Ammi majus L. (Apiaceae) cultures contain trace amounts of the product. Arbutin is accumulated in cells; it is occasionally found in media only in vestigial amounts. In most of the investigated cultures the efficiency of the biotransformation process is about 60 %.     

Detection of the Quarantine Species Thrips palmi by Loop-Mediated Isothermal Amplification

Thrips palmi (from the order Thysanoptera) is a serious insect pest of various crops, including vegetables, fruits and ornamental plants, causing significant economic losses. Its presence constitutes a double threat; not only does T. palmi feed on the plants, it is also a vector for several plant viruses. T. palmi originated in Asia, but has spread to North and Central America, Africa, Oceania and the Caribbean in recent decades. This species has been sporadically noted in Europe and is under quarantine regulation in the European Union. For non-specialists its larval stages are indistinguishable morphologically from another widespread and serious insect pest Frankliniella occidentalis (a non-quarantine species in the European Union) as well as other frequently occurring thrips. In this study, we have developed a loop-mediated isothermal amplification protocol to amplify rDNA regions of T. palmi. The results were consistent whether isolated DNA or crushed insects were used as template, indicating that the DNA isolation step could be omitted. The described method is species-specific and sensitive and provides a rapid diagnostic tool to detect T. palmi in the field.     

Cytochemical distribution of beta-glucuronidase activity in experimental brain tumors and brain tissue in vivo and in vitro

Summary Activity of beta-glucuronidase in experimental brain tumors and in nervous tissue was studied. The activity of the enzyme was detected both in gliomas and sarcomas exhibiting a high degree of anaplasia and dysplasia. Reactive glia showed high enzymatic activity; whereas activity in normal nervous tissue was absent. In tissue culture the activity of beta-glucuronidase was observed mainly in astrocytes, and its intensity expressed the degree of cellular maturation and differentiation.The investigation was carried out under a grant from PL 480 US Public Health Service Program, Agreement 05-004-1.     

Uptake and Population-Level Impact of Expedited Partner Therapy (EPT) on Chlamydia trachomatis and Neisseria gonorrhoeae: The Washington State Community-Level Randomized Trial of EPT

BackgroundExpedited partner therapy (EPT), the practice of treating the sex partners of persons with sexually transmitted infections without their medical evaluation, increases partner treatment and decreases gonorrhea and chlamydia reinfection rates. We conducted a stepped-wedge, community-level randomized trial to determine whether a public health intervention promoting EPT could increase its use and decrease chlamydia test positivity and gonorrhea incidence in women.ConclusionsA public health intervention promoting the use of free PDPT substantially increased its use and may have resulted in decreased chlamydial and gonococcal infections at the population level.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01665690","term_id":"NCT01665690"}}NCT01665690     

Application of enzymatic apple pomace hydrolysate to production of 2,3-butanediol by alkaliphilic <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> NCIMB 8059

2,3-Butanediol (2,3-BD) synthesis by a nonpathogenic bacterium Bacillus licheniformis NCIMB 8059 from enzymatic hydrolysate of depectinized apple pomace and its blend with glucose was studied. In shake flasks, the maximum diol concentration in fed-batch fermentations was 113 g/L (in 163 h, from the hydrolysate, feedings with glucose) while in batch processes it was around 27 g/L (in 32 h, from the hydrolysate and glucose blend). Fed-batch fermentations in the 0.75 and 30 L fermenters yielded 87.71 g/L 2,3-BD in 160 h, and 72.39 g/L 2,3-BD in 94 h, respectively (from the hydrolysate and glucose blend, feedings with glucose). The hydrolysate of apple pomace, which was for the first time used for microbial 2,3-BD production is not only a source of sugars but also essential minerals.     

A common site of the Fc receptor gamma subunit interacts with the unrelated immunoreceptors FcalphaRI and FcepsilonRI

The transmembrane (TM) region of the Fc receptor-gamma (FcRgamma) chain is responsible for the association of this ubiquitous signal transduction subunit with many immunoreceptor ligand binding chains, making FcRgamma key to a number of leukocyte activities in immunity and disease. Some receptors contain a TM arginine residue that interacts with Asp-11 of the FcRgamma subunit, but otherwise the molecular basis for the FcRgamma subunit interactions is largely unknown. This study reports residues in the TM region of the FcRgamma subunit are important for association with the high affinity IgE receptor FcepsilonRI and a leukocyte receptor cluster member, the IgA receptor FcalphaRI. FcRgamma residue Leu-21 was essential for surface expression of FcepsilonRIalpha/gamma2 and Tyr-8, Leu-14, and Phe-15 contributed to expression. Likewise, detergent-stable FcRgamma association with FcalphaRI was also dependent on Leu-14 and Leu-21 and in addition required residues Tyr-17, Tyr-25, and Cys-26. Modeling the TM regions of the FcRgamma dimer indicated these residues interacting with both FcalphaRI and FcepsilonRI are near the interface between the two FcRgamma TM helices. Furthermore, the FcRgamma residues interacting with FcalphaRI form a leucine zipper-like interface with mutagenesis confirming a complementary interface comprising FcalphaRI residues Leu-217, Leu-220, and Leu-224. The dependence of these two nonhomologous receptor interactions on FcRgamma Leu-14 and Leu-21 suggests that all the associated Fc receptors and the activating leukocyte receptor cluster members interact with this one site. Taken together these data provide a molecular basis for understanding how disparate receptor families assemble with the FcRgamma subunit.     

Structure and heterogeneity of the O-antigen chain of Salmonella Agona lipopolysaccharide

Lipopolysaccharide of Salmonella Agona smooth-type cells was obtained from bacteria by a hot phenol-water extraction procedure. Mild acid hydrolysis of lipopolysaccharide, followed by gel filtration, yielded the pure O-polysaccharide. Abequose, rhamnose, mannose, galactose and glucose in the molar ratio 0.8 : 1.0 : 1.0 : 1.1 : 0.5 were detected, and their linkages were established. Sugar configurations were determined by gas chromatography. Two repeating units, namely -->2)-[alpha-Abep-(1-->3)-]-alpha-d-Manp-(1-->4)-alpha-l-Rhap-(1-->3)-alpha-d-Galp-(1-->and -->2)-[alpha-Abep-(1-->3)-]-alpha-d-Manp-(1-->4)-alpha-l-Rhap-(1-->3)-[alpha-d-Glcp-(1-->4)-]-alpha-d-Galp-(1-->, were deduced from nuclear magnetic resonance studies. The effort to separate them was unsuccessful. An immunochemical test performed by means of Western blotting with anti O12 serum demonstrated that glucose was present in the longer lipopolysaccharide chains, at some distance from the core region.