Angiotensin II stimulates cAMP production and protein tyrosine phosphorylation in mouse spermatozoa

Angiotensin II (AII), found in seminal plasma, has been shown to stimulate capacitation in uncapacitated mammalian spermatozoa. The present study investigated the location of AII receptors on spermatozoa and AII's mechanism of action. AT1 type receptors for AII are present on the acrosomal cap region and along the whole of the flagellum of both mouse and human spermatozoa. Because combinations of low concentrations of AII and either calcitonin or fertilization-promoting peptide (FPP), both known to regulate the adenylyl cyclase (AC)/cAMP signal transduction pathway, elicited a significant response, this study investigated the hypothesis that these peptides act on the same pathway. AII was shown to significantly stimulate cAMP production in both uncapacitated and capacitated mouse spermatozoa and this was associated with increases in protein tyrosine phosphorylation. Using an anti-phosphotyrosine antibody to visualize the location of tyrosine phosphoproteins within individual cells, AII significantly stimulated phosphorylation within 20 min in both the head, especially in the acrosomal cap region, and the flagellum, especially in the principal piece, of uncapacitated mouse spermatozoa; combined AII + FPP was stimulatory within 5 min. In addition, Western blotting revealed that AII stimulation increased phosphorylation in a number of tyrosine phosphoproteins in both uncapacitated and capacitated mouse spermatozoa, with some being altered only in the latter category of cells. These results support the hypothesis that AII stimulates AC/cAMP in mammalian spermatozoa.     

Photodecomposition of Bil3 films

The effect of illumination on the transmittance and the structure of Bil₃ films was investigated. Photoexcitation was found to induce structural variation and decomposition of the films into metallic bismuth and free iodine. Moreover, measurements of the electrical conductivity during heating show thermal decomposition of the films and it was found that the temperature of decomposition depends on the thickness of the film.     

Studies on granuloma formation in Syrian hamsters experimentally infected with Schistosoma mansoni

Juvenile rats are more susceptible to the acute toxicity of the phosphorothionate insecticides parathion and chlorpyrifos than are adult rats. Developmental changes in brain acetylcholinesterase and hepatic aliesterase (carboxylesterase), cytochrome P450, and the P450-mediated metabolism of these two phosphorothionate insecticides were investigated in male Sprague-Dawley rats. Specific activities of acetylcholinesterase in cerebral cortex, but not medulla oblongata, and of liver aliesterases increased with age, indicating the presence of both more target esterases and more protective esterases, respectively, in the adult compared to the juvenile animal. Sensitivity of the brain acetylcholinesterase to inhibition by paraoxon and chlorpyrifosoxon, as measured by IC50 values, did not change significantly with age, whereas the hepatic aliesterase sensitivity to inhibition decreased with age. Progressive increases in activities of P450-mediated activation (desulfuration) (6- to 14-fold) and detoxication (dearylation) (2- to 4-fold), as well as concentrations of P450 (7-fold) and protein (2-fold), were observed between neonate and adult hepatic microsomes. Microsomal pentoxyresorufin O-dealkylase activity followed a developmental pattern similar to desulfuration and dearylation, displaying a 16-fold increase between neonates and adults. However, microsomal ethoxyresorufin O-deethylase activity increased until 21 days of age, displaying a 16-fold increase, then decreased in adulthood to a level 10-fold higher than neonates. These results indicate that target enzyme sensitivity is not responsible for age-related toxicity differences, nor is the potential for hepatic bioactivation, whereas lower levels of hepatic aliesterase-mediated protection and P450-mediated dearylation probably contribute significantly to the greater sensitivity of juveniles to phosphorothionate toxicity.     

Optimization of alkylresorcinols extraction from triticale bran using response surface methodology

Optimization conditions for alkylresorcinols (ARs) extraction from triticale bran were determined using response surface methodology. A central composite design was used to determine the effects of extraction temperature (degrees Celsius) and solid-to-solvent ratio (weight per volume) on yield of saturated, unsaturated and total ARs. Extraction of ARs was affected significantly (p value????0.05) by temperature and solid-to-solvent ratio on the yield of saturated, unsaturated and total ARs. The highest quantity of total ARs from triticale bran was extracted at 24?°C between 16 and 24?h at a solid-to-solvent ratio (weight per volume) of 1:40 and ranged from 278 to 308?mg/100?g, while saturated and unsaturated ARs were 163 to 225?mg/100?g and 22 to 29?mg/100?g, respectively. The ARs identified by high-performance liquid chromatography included: C15:0, C17:0, C19:0, C21:0, C23:0 and C25:0. Also some unsaturated analogues (12.4% to 14.0%) were found including C17:1, C19:1, C21:1 and C23:1. Analysis of variance (p value?=?0.05) indicated that the response surface methodology (RSM) developed for saturated, unsaturated and total ARs were adequate and explained most of the variability (85% to 89%) with high coefficient of multiple determination (R ²?=?0.89). The main effect of the response variable was quadratic rather than a linear function. Our results showed that RSM is a tool that is useful to optimise experimental conditions for the extraction of ARs.     

Effect of organic solvents on growth of freshwater algae

The impact of acetone, methanol, ethanol and dimethyl sulfoxide (DMSO) as carrier solvents on two species of algae was investigated. Scenedesmus quadricauda of green algae and Anabaena flos‐aquae of blue green algae were subjected to different concentrations of the studied solvents which ranged from 0.01 to 7.29 mL/L for 10 days in batch studies. The data recommended the use of acetone, ethanol and methanol than dimethyl sulfoxide in this order as a carrier solvent for chemical toxicity tests using a maximum concentration of 7.29 mL/L which represents 0.729% (volume/volume) in the algal bioassay test.     

1,3-Dimethylpyrimidoheterocycles as antibacterial agents

1,3-Dimethylbarbituric acid was used as a versatile precursor for the preparation of annelated pyranopyrimidines 2 and 3a-c besides pyrrolopyrimidine 12. The isolated pyrazolopyrimidines 8a-c and 10 and fused pyrazolopyrimidines 14a-d were also synthesized. In addition the new obtained pyrimidoheterocycles were subjected to bacterial testings.     

Chitosan phosphate induced better thermal characteristics to cotton fabric

Chitosan phosphate was prepared and applied at different concentrations with and without low formaldehyde N‐methylol finishing agent (resin) to cotton fabrics. Chitosan phosphate was characterized by FTIR, nitrogen content, and phosphorus content. The so‐treated fabrics were monitored for thermogravimetric analysis (maximum decomposition temperature and residue contents after decomposition), nitrogen content, phosphorus content, tensile strength, and elongation at break. Results indicate that extent of reaction of chitosan phosphate with the cotton fabric relies on concentration of the former; increasing the concentration of the resin has practically no effect on this reaction though the resin functions as a chemical bridge between the chitosan phosphate and the cotton fabric. On the other hand, the nitrogen of the resin and the phosphorus of chitosan undergo synergetic effect and enhance the thermal properties of the treated cotton. Strength properties display higher values in the presence than in the absence of chitosan phosphate when the latter was used along with the resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2021–2026, 2007     

Hydroxyapatite, fluor-hydroxyapatite and fluorapatite produced via the sol–gel method: dissolution behaviour and biological properties after crystallisation

Hydroxyapatite (HA), fluor-hydroxyapatite (FHA) with varying levels of fluoride ion substitution and fluorapatite (FA) were synthesised by the sol–gel method as possible implant coating or bone-grafting materials. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol–water based solution. Different amounts of ammonium fluoride were incorporated for the preparation of the FHA and FA sol–gels. After heating and powdering the sol–gels, dissolution behaviour was assessed using ion chromatography to measure Ca²⁺ and PO₄ ^3? ion release. Biological behaviour was assessed using cellular proliferation with human osteosarcoma cells and alamarBlue? assay. Statistical analysis was performed with a two way analysis of variance and post hoc testing with a Bonferroni correction. Increasing fluoride substitution into an apatite structure decreased the dissolution rate. Increasing the firing temperature of the HA, FHA and FA sol–gels up to 1,000 °C decreased the dissolution rate. There was significantly higher cellular proliferation on highly substituted FHA and FA than on HA or Titanium. The properties of an implant coating or bone grafting material can be tailored to meet specific requirements by altering the amount of fluoride that is incorporated into the original apatite structure. The dissolution behaviour can further be altered by the temperature at which the sol–gel is fired.