Phytochrome control of β-fructosidase activity in radish

Soluble and cell-wall fractions from radish seedlings show β-fructosidase activity. Light (via phytochrome) induces a transfer of the enzyme from the cytosol to the cell-wall in roots and hypocotyls. Light also increases β-fructosidase activity in hypocotyls. Cycloheximide prevents the increase of β-fructosidase activity but has no effect on the transfer.     

Comparative study of four extraction methods for enterovirus recovery from wastewater and sewage sludge

This study investigated four methods for the recovery of enteroviruses from sterilized raw wastewater, activated sludge, thickened sludge and treated wastewater, inoculated with Echovirus 11, Gregory prototype. The adsorption-elution method recommended by the US Environmental Protection Agency (EPA) was better for Echovirus 11 recovery than a sonication method, a modified EPA method and a membrane adsorption elution method since it resulted in the highest detection levels by cell culture and RT-PCR (Friedman's test, p<0.00041 and p=0.041, respectively).     

Combined effect of temperature and light intensity on growth and extracellular polymeric substance production by the cyanobacterium Arthrospira platensis

The effects of light intensity and temperature on Arthrospira platensis growth and production of extracellular polymeric substances (EPS) in batch culture were evaluated using a three-level, full-factorial design and response surface methodology. Three levels were tested for each parameter (temperature: 30, 35, 40°C; light intensity: 50, 115, 180 μmol photons m⁻² s⁻¹). Both growth and EPS production are influenced mainly by the temperature factor but the interaction term temperature*light intensity also had a significant effect. In addition, conditions optimising EPS production are different from those optimising growth. The highest growth rate (0.414 ± 0.003 day⁻¹) was found at the lowest temperature (30°C) and highest light intensity (180 μmol photons m⁻² s⁻¹) tested, no optima were detectable within the given test range. Obviously, optima for growth must be at a temperature lower than 30°C and a light intensity higher than 180 μmol photons m⁻² s⁻¹. For EPS production, light intensity had a positive linear effect (optimum obviously higher than 180 μmol photons m⁻² s⁻¹), but for the temperature parameter a maximum effect was detectable at 35°C.     

Discovery of tetrahydro-cyclopenta[b]indole as selective LXRs modulator

A series of tetrahydro-cyclopenta[b]indoles modulating the activity of the liver-X-receptor (LXR) were derived from a high throughput screening hit. The potency and selectivity for LXRβ versus LXRα was improved. One compound, administered to wild-type mice modestly increased plasma HDL-cholesterol with no change in plasma triglycerides (TG) and reduced effects on liver TG content compared to T0901317. This novel series of LXR agonists shows promise to improve therapeutic efficacy with reduced potential to increase TG.     

Phenotypic and genotypic typing of<Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Enteritidis isolates from poultry farms environments in Tunisia

Salmonella enterica serovar Enteritidis is one of the majorSalmonella serovars which may cause animal infections and human salmonellosis. In this study, two hundred forty five samples (faeces, water and environmental swabs) were taken from eight poultry farms localized in different geographical areas of Tunisia. We foundSalmonella serovar Enteritidis (16 strains),Salmonella typhimirium (2),Salmonella scharzengrund (2), andSalmonella braenderup (1).Salmonella Enteritidis strains were characterized by pulsed field gel electrophoresis (PFGE) analysis, plasmid analysis and antibiotic resistance profiles.XbaI PFGE analysis revealed two PFGE types and plasmid profiling identified four plasmid types. The majority of isolates were susceptible to all antibiotic tested. The combined use of phenotypic and genotypic methods indicates the spread of a particularSalmonella Enteritidis clone. This clone is highly related to a major world-wide clone identified in many other countries.     

δ versus μ receptors: cardiovascular and respiratory effects of opiate agonists microinjected into nucleus tractus solitarius of cats

The cardiovascular and respiratory responses to relatively specific μ or δ agonists microinjected (0.5 μl/kg) into the region of the nucleus of tractus solitarius (NTS) were examined in anesthetized cats. Blood pressure, heart rate, and respiratory rate were monitored for 30 min after the microinjection of opioid compounds or saline vehicle. The δ agonist, (d-Ala²,d-Leu⁵)-enkephalin (10–100 nmol/kg) elicited dose-dependent decreases in blood pressure, heart rate, and respiratory rate which were naloxone reversible. In contrast the μ agonists, morphine (10–54 nmol/kg) and morphiceptin (100–320 nmol/kg) had no effect on blood pressure or respiratory rate; yet, naloxone elicited pressor responses in animals pretreated with these μ agonists. A receptor-binding assay demonstrated a predominance of μ sites in the NTS. These data show that the δ opiate agonist is more effective than μ agonists in modifying cardiovascular variables in the NTS; we suggest caution in relating specific cardiovascular function to receptor subtypes defined by binding assays.     

Two novel transferable extended-spectrum β-lactamases from Klebsiella pneumoniae in Tunisia

Two novel beta-lactamases conferring multiresistance to antibiotics including oxyimino beta-lactams have been identified in two nosocomial K. pneumoniae strains isolated in Tunis in 1986 and 1988. Both enzymes were encoded by ca. 150-kilobase plasmids. Donor and transconjugant strains producing these enzymes exhibited highly similar pattern of resistance (CTX phenotype) to beta-lactams including penicillins and oxyimino beta-lactams e.g. cefotaxime, ceftriaxone, ceftazidime, and aztreonam. High and variable synergy (16 to 1066-fold) was obtained when combined to 0.1 microgram/ml of clavulanate (beta-lactamase inhibitor). The isoelectric points of these two enzymes were 5.4 and 6.4. These beta-lactamases differed from TEM types by hydrolysis for cefotaxime or ceftriaxone but were inhibited by clavulanate and cloxacillin. DNA hybridization studies suggested that that the genes of these enzymes may be derived from genes encoding TEM-type enzymes.