Overexpression of phospholipase C-gamma1 in rat 3Y1 fibroblast cells leads to malignant transformation

Phospholipase C-gamma1 (PLC-gamma1) mediates signals from various extracellular origins to evoke cellular events such as mitogenesis. Previously, we reported that PLC-gamma1 was highly expressed in colorectal cancer and familial adenomatous polyposis, suggesting that PLC-gamma1 might be oncogenic. In this study, we have established rat 3Y1 fibroblasts that overexpress whole PLC-gamma1 and src homology 2 (SH2)-SH2-SH3 domain of PLC-gamma1. These cells showed a transformed phenotype and were tumorigenic when transplanted into nude mice. These results indicate that overexpression of PLC-gamma1 could transform rat fibroblasts, and the transformation is mediated by SH2-SH2-SH3 domain of PLC-gamma1.     

Sex-related differences in cadmium-induced alteration of drug action in the rat

A case of multiple adenocarcinoma arising from the kidney, bladder, and prostate is presented with a relevant discussion of the possible factors of pathogenesis. A staged approach of radical extirpative surgery is suggested.     

Polarisation characteristics in long length v.a.d. single-mode fibres

Polarisation characteristics in long single-mode fibres are investigated. Single-mode fibres used in the experiment have been fabricated by the v.a.d. (vapour-phase axial deposition) method. It was shown from the measurements on a 21 km single-span v.a.d. fibre that the state of polarisation of the incident light beam can be maintained over a long length when the incident plane of polarisation coincides with the major or minor axis of the single-mode optical fibre.     

Albumin stabilizes (–)‐epigallocatechin gallate in human serum: Binding capacity and antioxidant property

(–)‐Epigallocatechin gallate (EGCg) is the major component of green tea and is known to show strong biological activity, although it can be easily oxidized under physiological conditions. In this study, we indicate that EGCg is stable in human serum and that human serum albumin (HSA) stabilizes EGCg under aerobic condition. Although EGCg is usually decomposed within 1 h in aqueous solution at neutral pH, EGCg in serum and phosphate buffer (pH 7.4) containing HSA was stable over 1 h, even at neutral and slightly alkaline pH. Under these conditions, EGCg binds to HSA non‐covalently. The sulfhydryl group acts as an antioxidant for EGCg oxidation. Incubation of EGCg with HSA is accompanied by the oxidation of a free sulfhydryl group in HSA. These results suggest that the antioxidant property and the binding capacity of HSA contribute to the stabilization of EGCg in human serum.     

Discussion on the equivalent conductivity and resistance of stress corrosion cracks in eddy current simulations

This study evaluates the numerical modeling of stress corrosion cracks from the viewpoint of eddy current simulations. Five stress corrosion cracks are artificially introduced into austenitic stainless steel plates measuring 25 mm in thickness, and then eddy current inspections are conducted to gather eddy current signals and destructive tests performed to confirm the true profiles of the cracks. The cracks are carefully introduced so as not to cluster, and the data obtained enables discussion of the modeling of a single crack quantitatively. Subsequent numerical simulations model each crack as a rectangular region with a fixed width and uniform conductivity, and evaluate the equivalent width and conductivity suitable for modeling the crack. The evaluation reveals that it is not reasonable to correlate the size of a crack and only its width or conductivity, and larger cracks tend to have greater resistance, which is defined as the width divided by conductivity. Furthermore, the values of width and conductivity depend also on the exciting frequency and probe used; however, the resistance remains almost unchanged by the experimental condition.     

Derepressed hyphal growth and reduced virulence in a VH1 family-related protein phosphatase mutant of the human pathogen Candida albicans

Mitogen-activated protein (MAP) kinases are pivotal components of eukaryotic signaling cascades. Phosphorylation of tyrosine and threonine residues activates MAP kinases, but either dual-specificity or monospecificity phosphatases can inactivate them. The Candida albicans CPP1 gene, a structural member of the VH1 family of dual- specificity phosphatases, was previously cloned by its ability to block the pheromone response MAP kinase cascade in Saccharomyces cerevisiae. Cpp1p inactivated mammalian MAP kinases in vitro and acted as a tyrosine-specific enzyme. In C. albicans a MAP kinase cascade can trigger the transition from the budding yeast form to a more invasive filamentous form. Disruption of the CPP1 gene in C. albicans derepressed the yeast to hyphal transition at ambient temperatures, on solid surfaces. A hyphal growth rate defect under physiological conditions in vitro was also observed and could explain a reduction in virulence associated with reduced fungal burden in the kidneys seen in a systemic mouse model. A hyper-hyphal pathway may thus have some detrimental effects on C. albicans cells. Disruption of the MAP kinase homologue CEK1 suppressed the morphological effects of the CPP1 disruption in C. albicans. The results presented here demonstrate the biological importance of a tyrosine phosphatase in cell-fate decisions and virulence in C. albicans.     

Behavior of cellulose-degrading bacteria in thermophilic anaerobic digestion process.

Previously, we found that the newly isolated Clostridium sp. strain JC3 became the dominant cellulose-degrading bacterium in thermophilic methanogenic sludge. In the present study, the behavior of strain JC3 in the thermophilic anaerobic digestion process was investigated quantitatively by molecular biological techniques. A cellulose-degrading experiment was conducted at 55 degrees C with a 9.5 L of anaerobic baffled reactor having three compartments (Nos. 1, 2, 3). Over 80% of the COD input was converted into methane when 2.5 kgCOD m(-3) d(-1) was loaded for an HRT of 27 days. A FISH probe specific for strain JC3 was applied to sludge samples harvested from the baffled reactor. Consequently, the ratio of JC3 cells to DAPI-stained cells increased from below 0.5% (undetectable) to 9.4% (compartment 1), 13.1% (compartment 2) and 21.6% (compartment 3) at day 84 (2.5 kgCOD m(-3)d(-1)). The strain JC3 cell numbers determined by FISH correlated closely with the cellulose-degrading methanogenic activities of retained sludge. A specific primer set targeting the cellulase gene (cellobiohydrolaseA: cbhA) of strain JC3 was designed and applied to digested sludge for treating solid waste such as coffee grounds, wastepaper, garbage, cellulose and so on. The strain JC3 cell numbers determined by quantitative PCR correlated closely with the cellulose-sludge loading of the thermophilic digester. Strain JC3 is thus important in the anaerobic hydrolysis of cellulose in thermophilic anaerobic digestion processes.     

Evaluation of phosphate removal from water by immobilized phosphate-binding protein PstS

The phosphate (P(i))-binding protein PstS is a member of a family of periplasmic proteins that act as high-affinity receptors for active transport systems in bacteria. PstS protein purified from Pseudomonas aeruginosa was immobilized to N-hydroxysuccinimide-activated Sepharose, packed into a plastic column (5 x 70 mm), and examined for its potential ability to remove P(i) from water. The PstS-Sepharose column completely removed P(i) from 32P-labeled pond water containing about 0.5 microM P(i) (0.015 mg P per liter). More than 90% of 32P-P(i) that was retained in the column could be eluted by washing with low-pH water.