Further indications of the multicomponent nature of the acrosome reaction-inducing substance of human follicular fluid

Human follicular fluid (hFF), which has been treated with either unspecific proteases or dextran-coated charcoal (DCC) to remove proteins and/or steroids, cannot successfully induce the acrosome reaction (AR). After the removal of steroids, AR-inducing activity can be restored to hFF by supplementation with exogenous progesterone, but only in the presence of intact protein. Gel filtration experiments with ³H-progesterone-labelled hFF showed elution of the radioactive signal in the high molecular weight range, corresponding to bound progesterone. AR-inducing activity was seen in exactly the same fraction. Based on these results, the acrosome reaction-inducing substance (ARIS) appears to be a complex of progesterone and a progesterone-binding protein, which was shown to be identical with the plasma protein corticosteroid-binding globulin (CBG) by immunological techniques. AR induction was only observed in the presence of both CBG and progesterone, suggesting a combined effect of the two components. © 1995 wiley-Liss, Inc.     

A rare genetically determined variant of psuedocholinesterase in two German families with high plasma enzyme activity.

Activity of pseudocholinesterase (acylcholine-acyl-hydrolase) elevated up to four times has been detected in sera of members of two German families. The catalytic concentrations of the pseudocholinesterase of the afflicted members of both families (male and female) varied between 4800 U/l and 10 200 U/o (acetylthiocholine iodide substrate). The pseudocholinesterase of the propositi exhibits isoenzyme separation patterns in polyacrylamide electrophoresis as well as in electrofocussing which are different from those of pseudocholinesterase from normal persons. No differences could be seen as regards the Km of substrates or the inhibition by dibucaine, fluoride or succinyldiocholine.     

Micro Flow-Through Thermocycler with Simple Meandering Channel with Symmetric Temperature Zones for Disposable PCR-Devices in Microscope Slide Format

Chip-based flow-through PCR implements the PCR as a continuous process for nucleic acid analytics. The sample is transported in a winding channel through temperature zones required for denaturation, annealing and extension. Main fields of application are the monitoring of continuous processes for rapid identification of contaminants and quality control as well as high throughput screening of cells or microorganisms. A modular arrangement with five heating zones for flow-through PCR is discussed and evaluated. The special heater arrangement allows the implementation of up to 40 cycles on the footprint of a microscope slide, which is placed on top ofa 5 zones heating plate. Liquid/liquid two phase flow of PCR reaction mixture and mineral oil have been applied to create a segmented flow process scheme. In that way, the developed system may provide flow-through PCR as a unit operation for the droplet based microfluidics platform. The single use of disposable devices is commonly preferred due to the sensitivity of the PCR process to contaminations. All-glass microfluidic chips and disposable chip devices, made from polycarbonate as a replication with identically geometry, have been fabricated and tested. For the first time, microchannel geometries with nearly circular profile developed by all-glass technology have been transferred to mass fabrication by injection compression molding. Both devices have been successfully applied for the detection of the tumor suppressor gene p53. Although product yield and selectivity of the amplification process do not depend on the chip material, a well defined, reliable segmented flow regime could only be realized in the all-glass chip.     

Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in Na+/K+ homeostasis

The location of major quantitative trait loci (QTL) contributing to stem and leaf [Na⁺] and [K⁺] was previously reported in chromosome 7 using two connected populations of recombinant inbred lines (RILs) of tomato. HKT1;1 and HKT1;2, two tomato Na⁺‐selective class I‐HKT transporters, were found to be closely linked, where the maximum logarithm of odds (LOD) score for these QTLs located. When a chromosome 7 linkage map based on 278 single‐nucleotide polymorphisms (SNPs) was used, the maximum LOD score position was only 35 kb from HKT1;1 and HKT1;2. Their expression patterns and phenotypic effects were further investigated in two near‐isogenic lines (NILs): 157‐14 (double homozygote for the cheesmaniae alleles) and 157‐17 (double homozygote for the lycopersicum alleles). The expression pattern for the HKT1;1 and HKT1;2 alleles was complex, possibly because of differences in their promoter sequences. High salinity had very little effect on root dry and fresh weight and consequently on the plant dry weight of NIL 157‐14 in comparison with 157‐17. A significant difference between NILs was also found for [K⁺] and the [Na⁺]/[K⁺] ratio in leaf and stem but not for [Na⁺] arising a disagreement with the corresponding RIL population. Their association with leaf [Na⁺] and salt tolerance in tomato is also discussed.     

Surfactin and fengycin contribute to the protection of a Bacillus subtilis strain against grape downy mildew by both direct effect and defence stimulation

Bacillus subtilis GLB191 (hereafter GLB191) is an efficient biological control agent against the biotrophic oomycete Plasmopara viticola, the causal agent of grapevine downy mildew. In this study, we show that GLB191 supernatant is also highly active against downy mildew and that the activity results from both direct effect against the pathogen and stimulation of the plant defences (induction of defence gene expression and callose production). High-performance thin-layer chromatography analysis revealed the presence of the cyclic lipopeptides fengycin and surfactin in the supernatant. Mutants affected in the production of fengycin and/or surfactin were thus obtained and allowed us to show that both surfactin and fengycin contribute to the double activity of GLB191 supernatant against downy mildew. Altogether, this study suggests that GLB191 supernatant could be used as a new biocontrol product against grapevine downy mildew.     

Genistein binding protein targets in dental pathogens

Oral pathogens have created a menace in recent years due to biofilm formation and antimicrobial drug resistance. The current treatment strategy works well with antibiotics. However, constant use of antibiotics creates a selective pressure, which increases adaptability of the pathogens. Therefore, it is of interest to analyze the potential targets of genistein in dental pathogens using computer aided prediction tools.     

Hemagglutinating and adherence properties of Staphylococcus saprophyticus: epidemiology and virulence in experimental urinary tract infection of rats

Abstract We studied hemagglutinating and adherence properties in Staphylococcus saprophyticus isolates originating from symptomatic urinary tract infections. 12/13 (92%) of strains adhered to Hep cells and 11/13 (85%) were able to agglutinate sheep erythrocytes. Adherence properties differed markedly between strains ( P < 0.0001. Two strains, one hemagglutinating and adherent and one negative for both properties were chosen for experimental urinary tract infections. Results indicate that presence of the hemagglutinin favours colonization of kidney tissue.     

Relationship between extra and intracellular sources of calcium and the contractile effect of thiopental in rat aorta

To evaluate the relationship between the vasocontractile effect of thiopental and the extra and intracellular sources of Ca2+, we analyzed both the contractile effect of the barbiturate on rat aortic rings and its ability to modify the intracellular calcium concentration in cultured rat aorta smooth muscle cells. Thiopental (10-310 microg/mL) contracted aortic rings only in the presence of extracellular Ca2+, and this effect was not blocked by verapamil or diltiazem. On the contrary, Ca2+ (0.1-3.1 mM) evoked contractions only when thiopental (100 microg/mL) was present. Although in calcium-free solution thiopental (100 microg/mL) did not contract aortic rings, it abolished the contractile effect of either phenylephrine (10(-6) M) or caffeine (10 mM). Finally, thiopental augmented the intracellular calcium concentration in cultured smooth muscle cells incubated either in the presence or absence of calcium. In conclusion, thiopental's vasocontractile effect depends on extracellular calcium influx, which is independent of L-calcium channels. The increase in intracellular Ca2+ concentration elicited by thiopental in Ca2+-free solution and its ability to block the effect of phenylephrine and caffeine suggest that this barbiturate can deplete intracellular pools of calcium. Therefore, the calcium entry pathway associated with the contractile effect of thiopental may correspond to the capacitative calcium entry model.