Changes on hemostatic parameters induced by 17beta-estradiol,ethinylestradiol, and the 17beta-aminoestrogen pentolame in the male Wistar rat

Oral contraceptives containing estrogens increases the incidence of thromboembolic events. In contrast, administration of 17beta-aminoestrogens prolonged blood clotting time (BCT) in rodents. We studied the effect of estradiol (E(2)), ethinylestradiol (EE) and pentolame on some screening hemostatic tests. BCT was evaluated 24, 48, 72 and 96 h post-treatment. Rats received subcutaneously (s.c.) for five consecutive days E(2) (0.1-1000 microg), EE (1-1000 microg), pentolame (0.1-1000 microg), or vehicle (propyleneglycol 0.3 ml). At 48 h post-treatment E(2) (1000 microg) diminished BCT (32%, P<0.01), in contrast pentolame (1000 microg) augmented BCT by 41% (P<0.01). After 72 h, E(2) showed procoagulant effects with 10, 100 and 1000 microg doses (-45, -30, and -21%, respectively). Significant effects on BCT of EE were observed 72 h after with 1000 microg (-12%, P<0.05). Animals were treated s.c. for two consecutive days with E(2) (3mg/100g), pentolame (4 mg), or vehicle (0.1 ml). BCT, bleeding time (BT), platelet aggregation (PA), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen concentration were determined. E(2) produced a significant diminution on BCT (-20%) after 72 h whereas pentolame increased BCT from 24 to 96 h (62%, maximal response at 48 h). APTT and PT coagulation times of the groups treated with E(2) and pentolame were lengthened (33 and 29%; 16 and 24%, respectively; P<0.05). Fibrinogen concentration increased (115%, P<0.01) only in the pentolame-treated group. Pentolame and E(2) produced any effects on BT and PA compared with control groups, indicating that platelet function was not modified. Our results indicate that E(2), EE and pentolame affects the plasmatic phase of the hemostatic mechanism.     

Isolation and characterization of diazotrophic growth promoting bacteria from rhizosphere of agricultural crops of Korea

Free-living nitrogen fixing bacteria were isolated from rhizosphere of seven different plant namely sesame, maize, wheat, soybean, lettuce, pepper and rice grown in Chungbuk Province, Korea. Five isolates with nitrogenase activity above 150nmol(-1) mg(-1) protein were identified based on, phenotypic and 16S rDNA sequences analysis. The strains were identified as Stenotrophomonas maltophilia (PM-1, PM-26), Bacillus fusiformis (PM-5, PM-24) and Pseudomonas fluorescens (PM-13), respectively. All the isolates produced indole-3-acetic acid (IAA), in the presence of tryptophan, ranging from 100.4 microg ml(-1) (PM-13) to 255 microg ml(-1) (PM-24). The isolate PM-24 (Bacillus fusiformis) exhibiting highest nitrogenase activity (3677.81 nmol h(-1) mg(-1) protein) and IAA production (255microg ml(-1)) has a promising potential for developing as a plant growth promoting rhizobacteria.     

Momordica charantia fruit juice stimulates glucose and amino acid uptakes in L6 myotubes

The fruit of Momordica charantia (family: Cucurbitacea) is used widely as a hypoglycaemic agent to treat diabetes mellitus (DM). The mechanism of the hypoglycaemic action of M. charantia in vitro is not fully understood. This study investigated the effect of M. charantia juice on either 3H-2-deoxyglucose or N-methyl-amino-a-isobutyric acid (14C-Me-AIB) uptake in L6 rat muscle cells cultured to the myotube stage. The fresh juice was centrifuged at 5000 rpm and the supernatant lyophilised. L6 myotubes were incubated with either insulin (100 nM), different concentrations (1-10 microg ml(-1)) of the juice or its chloroform extract or wortmannin (100 nM) over a period of 1- 6 h. The results were expressed as pmol min(-1) (mg cell protein)(-1), n = 6-8 for each value. Basal 3H-deoxyglucose and 14C-Me-AIB uptakes by L6 myotubes after 1 h of incubation were (means +/- S.E.M.) 32.14 +/- 1.34 and 13.48 +/- 1.86 pmol min(-1) (mg cell protein)(-1), respectively. Incubation of L6 myotubes with 100 nM insulin for 1 h resulted in significant (ANOVA, p < 0.05) increases in 3H-deoxyglucose and 14C-Me-AIB uptakes. Typically, 3H-deoxyglucose and 14C-Me-AIB uptakes in the presence of insulin were 58.57 +/- 4.49 and 29.52 +/- 3.41 pmol min(-1) (mg cell protein(-1)), respectively. Incubation of L6 myotubes with three different concentrations (1, 5 and 10 microg ml(-1)) of either the lyophilised juice or its chloroform extract resulted in time-dependent increases in 3H-deoxy-D-glucose and 14C-Me-AIB uptakes, with maximal uptakes occurring at a concentration of 5 microg ml(-1). Incubation of either insulin or the juice in the presence of wortmannin (a phosphatidylinositol 3-kinase inhibitor) resulted in a marked inhibition of 3H-deoxyglucose by L6 myotubes compared to the uptake obtained with either insulin or the juice alone. The results indicate that M. charantia fruit juice acts like insulin to exert its hypoglycaemic effect and moreover, it can stimulate amino acid uptake into skeletal muscle cells just like insulin.     

Enhanced kinetics of genetically engineered Burkholderia cepacia: the role of vgb in the hypoxic metabolism of 2-CBA

Application of Vitreoscilla hemoglobin (VHb) technology to 2-CBA degradation by Burkholderia cepacia strain DNT under hypoxic conditions was studied in continuous culture chemostats. Dechlorination abilities of both recombinant (VHb gene (vgb) containing) and untransformed cells were investigated at various dilution rates to ensure complete degradation of 2-CBA. As the dilution rate increased from 0.025 to 0.25 h(-1), the ratios of chloride release to degraded 2-CBA concentration decreased from 0.95 to 0.72 and from 0.89 to 0.39 for recombinant and untransformed cells, respectively. A nonstoichiometric relationship between chloride release and 2-CBA degradation was more pronounced for untransformed cells. Recombinant cell densities were 0.1-0.2. g L(-1) greater than untransformed cell densities for a range of dilution rates. As the dilution rate increased, the oxygen uptake rate (OUR) and the substrate utilization rate (SUR) decreased for both strains. The OUR/SUR ratio increased as the dilution rate increased for both strains but was much higher for the recombinant strain compared to untransformed cells. The specific 2-CBA degradation rate of recombinant cells was greater than that of untransformed cells (1.17 vs. 0.46 mg CBA (mg) day(-1), and half-saturation constants for recombinant cells were lower than those of untransformed cells (0.18 and 0.32 mg CBA L(-1), respectively). The pseudo-first-order degradation constants, k(1CBA) and k(1ACE), were higher for recombinant cells (6.5 L (mg cells)(-1) day(-1) and 95.6 L (mg cells)(-1) day(-1), respectively) than those of untransformed cells (1.44 L (mg cells)(-1) day(-1) and 73.7 L (mg cells)(-1) day(-1), respectively).     

The protons of gluconic acid are the major factor responsible for the dissolution of tricalcium phosphate by Burkholderia cepacia CC-Al74

Burkholderia cepacia CC-Al74 with a high ability for solubilizing tricalcium phosphate (TCP) was used to study the P-solubilization mechanism. We collected filtrates able to solubilize TCP from the cultures of strain CC-Al74 and demonstrated that the P-solubilization increased from 0 microg ml(-1) to 200 microg ml(-1) during exponential growth, when the pH decreased from 8 to 3. HPLC-analysis revealed that the solubilization of TCP was mainly caused by the release of 16.3 mM gluconic acid. At this concentration, gluconic acid was capable of solubilizing 376 microg ml(-1) of TCP whereas water at pH 3 only solubilized 35 microg ml(-1). The difference is due to the final H+ concentrations which were 13.5 mM and 1 mM in 16.3 mM gluconic acid and deionized water, respectively at pH 3.     

Effect of caffeic acid phenethyl ester on treatment of experimentally induced methicillin-resistant Staphylococcus epidermidis endophthalmitis in a rabbit model

This study investigated the anti-inflammatory effects of caffeic acid phenethyl ester (CAPE), a natural bee-produced compound, and compared it with corticosteroids in the treatment of experimentally induced methicillin-resistant Staphylococcus epidermidis (MRSE) endophthalmitis in addition to intravitreal antibiotics. An experimental endophthalmitis model was produced in 24 New Zealand albino rabbits by unilateral intravitreal injection of 0.1 ml of 4.7 x 10(4) colony-forming units (CFU) methicillin-resistant S. epidermidis. The animals were then divided randomly into three treatment groups and a control group, group 1 (six rabbits), received only intravitreal vancomycin (1.0 mg/0.1 ml); group 2 (six rabbits), received both intravitreal vancomycin (1.0 mg/0.1 ml) and intravitreal dexamethasone (400 microg/0.1 ml) and group 3 (six rabbits), received both intravitreal vancomycin (1.0 mg/0.1 ml) and subtenon CAPE (10 mg/0.3 ml) after 24 h post-infection. No treatment was given to the control group. Treatment efficacy was assessed by clinical examination, vitreous culture and histopathology. There were no statististically significant differences between clinical scores of all groups in examinations at 24 and 48 h post-infection (p = 0.915 and p = 0.067 respectively), but in examinations at 72 h post-infection and after 7 days post-infection, although the clinical scores of treatment groups were not significantly different from each other, they were significantly lower than the control group (p < 0.05). The culture results of all groups were sterile. As a result, CAPE was found to be as effective as dexamethasone in reducing inflammation in the treatment of experimental MRSE endophthalmitis when used with antibiotics. More studies are needed to determine the optimal administration route and effective dosage of this compound.     

Distinct human prolactin (hPRL) and growth hormone (hGH) behavior under bacteriophage lambda PL promoter control: temperature plays a major role in protein yields

When producing recombinant protein for therapy, it is desirable not only to obtain substantial amounts of the protein, but also to make sure that potential contaminants such as inducing agents are not present in the final product. To prevent this, one can use expression systems in which the promoter (lambdaP(L)) is activated by a temperature shift that denatures a repressor (e.g., cIts). In this manner, hGH was successfully expressed and secreted in Escherichia coli periplasm, with specific yields well above 1 microg ml(-1) A(600)(-1), after a temperature shift from 30 to 42 degrees C. However, attempts to express a related hormone, human prolactin, employing the same protocol were unsuccessful, providing 0.03 microg ml(-1) A(600)(-1) at the most. A process is described in which this labile protein is obtained from a cIts(-) strain under optimized temperature condition (37 degrees C). The highest periplasmic secretions of prolactin ever reported were thus obtained: 0.92+/-0.10 microg ml(-1) A(600)(-1) at an optical density of approximately 3 A(600) units in shake flask cultures and approximately 1 microg ml(-1) A(600)(-1), at an OD of 35 A(600) units, via a rapid and flexible batch feed process in laboratory bioreactor. Purified hPRL was monomeric, correctly processed (Mr=22,906), properly folded and bioactive (51.5+/-24.1 IU mg(-1)).     

Optimal conditions for the production of sulfated polysaccharide by marine microalga Gyrodinium impudicum strain KG03

A marine microalga Gyrodinium impudicum strain KG03 produced sulfated exopolysaccharide designated as p-KG03, which showed a strong antiviral activity against encephalomyocarditis virus (EMCV). To optimize culture conditions for the production of p-KG03, mineral salts, vitamins, plant growth hormones, temperature, pH and light conditions were examined. From this study, M-KG03 medium for the maximum production of p-KG03 was suggested as follows; NH(4)Cl 75 microM, NaH(3)PO(4) 200 microM, NaHCO(3) 50 microM, Na(2)SO(4) 10 microM, FeCl(2) x 6H(2)O 10 microM, MnCl(2) x 4H(2)O 0.1 microM, vitamin B(12) 0.75 microg, naphthalene acetic acid (NAA) 7.5 microg and myo-inositol 200 mg per liter of aged sea water. The optimal temperature and pH were 22.5 degrees C and 8.0, respectively. The optimal light conditions of intensity and period were 150 microE m(-2) s(-1) and 16:8 h light:dark cycle. Finally, the cell growth and p-KG03 production were measured in one liter of M-KG03 medium with 1% CO(2) and 50 ml min(-1) of airflow using two liters airlift balloon type photobioreactor (ABTPR). At these optimal conditions, p-KG03 production and cell growth were 134.6+/-5.9 mg l(-1) and 123,076+/-1,597 cells ml(-1), respectively, representing a 7.7 and 5.1 times compared with f/2 medium with Erlenmeyer flask culture (p-KG03 production 17.5+/-1.3 mg l(-1) and cell growth 24,311+/-1,291 cells ml(-1)).     

In vitro efficacy of ciprofloxacin alone and in combination with amoxycillin against Salmonella typhi isolates

Combined effect of ciprofloxacin (Ci) and amoxycillin (Ax) has been studied in vitro against 12 clinical isolates of S. typhi that showed Ci minimum inhibitory concentration (MIC) of > or =1 microg/ml. By agar dilution method, MIC values of Ax were 10-16 microg/ml for 11 isolates and 0.5 microg/ml for the remaining one isolate. The isolates, when treated with Ci and Ax in combination, showed fractional inhibitory concentration (FIC) of 0.004-0.256 microg/ml for Ci. FIC of Ax ranged from 6-10 microg/ml, except for a single isolate that showed Ax FIC of 0.25 microg/ml. Thus Ci was more efficacious in combination with Ax against S. typhi than Ci alone. The antibiotic combination exhibited an additive effect for all the isolates showing FIC index 0.504-0.832.     

Modulation of chemotaxis, O(2)(-) production and myeloperoxidase release from human polymorphonuclear leukocytes by the ornithine-containing lipid and the serineglycine-containing lipid of Flavobacterium

The ornithine-containing lipid (OL) and the serineglycine-containing lipid (SGL) of Flavobacterium activated and modulated the functions of human polymorphonuclear leukocytes (PMNs). The OL and the SGL strongly activated fMet-Leu-Phe- and interleukin-8-induced chemotaxis of PMNs at the concentration of 0.1 microg ml(-1), and a synthetic OL also activated the function of PMNs. Further, the OL strongly activated O(2)(-) production from PMNs. Although the OL and the SGL slightly modulated myeloperoxidase release from PMNs, inhibition effects of their component fatty acid analogues were observed. O(2)(-) production-inducing activity is a common biological activity between the OL and bacterial lipopolysaccharides, but OL and SGL, unlike lipopolysaccharide, are potent activators of PMN chemotaxis.     

Toluene bioconversion to p-hydroxybenzoate by fed-batch cultures of recombinant Pseudomonas putida.

A microbial oxidation process for the production of p-hydroxybenzoate (HBA) from toluene is reported. The oxidation reaction was studied in fed-batch fermentations using a recombinant Pseudomonas putida grown on glutamate as the sole carbon and energy source with salicylate and IPTG induction of tmoABCDE, and pchCF and phbz pathway genes, respectively. An average volumetric HBA productivity of 13.4 mg HBA x L(-1) x h(-1) was obtained under rapid growth conditions (glutamate excess), giving an HBA titer of 132 mg x L(-1) after 9.8 h of fermentation. This corresponded to an average specific HBA productivity of 7.2 microg HBA (mg total protein)(-1) x h(-1). In contrast, maximum HBA titers of 35 mg HBA x L(-1) were achieved in 27 h in comparative studies employing glutumate limited fed-batch cultures. A specific productivity of 4.1 microg HBA (mg total protein)(-1) x h(-1) and volumetric productivity of 1.3 mg HBA x L(-1) x h(-1) were calculated for the growth-rate restricted cultures. The differences in HBA production between the two cultures could be correlated to the levels of specific toluene-4-monooxygenase (T4MO) polypeptides. T4MO catalyzes the rate-limiting step in the pathway. Using experimental data, the half-life value of TmoA was calculated to be approximately 28 h. Assuming linear, monomolecular decay of TmoA, a specific degradation constant of 0.025 x h(-1) was calculated, which placed the stability of recombinant TmoA in the range of relatively stable proteins, even in the absence of co-expression of tmoF, the terminal oxidoreductase subunit of T4MO.     

Flow cytometry assessment of bacterioplankton in tropical marine environments

Flow cytometry was used to characterize bacterioplankton from two tropical environments in Brazil: the eutrophic Guanabara Bay and the oligotrophic southwest Atlantic Ocean. Bacterial abundance was evaluated by flow cytometry, and cells were stained with SYTO 13, allowing demonstration of differences in nucleic acid content. Bacterial production was also evaluated by means of 3H-leucine incorporation. Bacterial numbers were different for both sites. In Atlantic Ocean samples, we found a maximum of 5.50 x 10(5) cells ml(-1), and low nucleic acid content organisms predominated. In Guanabara Bay, bacterial numbers were one order of magnitude higher than in the ocean, and they varied from outer bay (1.01 x 10(6) cells ml(-1)) to inner bay (6.90 x 10(6) cells ml(-1)). Bacterial activity in ocean samples varied from 4.6 to 126 ng C l(-1) h(-1), while in the bay, mean values ranged from 1.95 microg C l(-1) h(-1) (outer bay) to 7.35 microg C l(-1) h(-1) (inner bay). Values found for both parameters are characteristic of different trophic situations. These results illustrate the utility of cytometric analyses of bacterioplankton populations in characterizing their large spatial and temporal scales of distribution in aquatic ecosystems.     

Modeling reduction of uranium U(VI) under variable sulfate concentrations by sulfate-reducing bacteria

The kinetics for the reduction of sulfate alone and for concurrent uranium [U(VI)] and sulfate reduction, by mixed and pure cultures of sulfate-reducing bacteria (SRB) at 21 +/- 3 degrees C were studied. The mixed culture contained the SRB Desulfovibrio vulgaris along with a Clostridium sp. determined via 16S ribosomal DNA analysis. The pure culture was Desulfovibrio desulfuricans (ATCC 7757). A zero-order model best fit the data for the reduction of sulfate from 0.1 to 10 mM. A lag time occurred below cell concentrations of 0.1 mg (dry weight) of cells/ml. For the mixed culture, average values for the maximum specific reaction rate, V(max), ranged from 2.4 +/- 0.2 micromol of sulfate/mg (dry weight) of SRB. h(-1)) at 0.25 mM sulfate to 5.0 +/- 1.1 micromol of sulfate/mg (dry weight) of SRB. h(-1) at 10 mM sulfate (average cell concentration, 0.52 mg [dry weight]/ml). For the pure culture, V(max) was 1.6 +/- 0.2 micromol of sulfate/mg (dry weight) of SRB. h(-1) at 1 mM sulfate (0.29 mg [dry weight] of cells/ml). When both electron acceptors were present, sulfate reduction remained zero order for both cultures, while uranium reduction was first order, with rate constants of 0.071 +/- 0.003 mg (dry weight) of cells/ml. min(-1) for the mixed culture and 0.137 +/- 0.016 mg (dry weight) of cells/ml. min(-1) (U(0) = 1 mM) for the D. desulfuricans culture. Both cultures exhibited a faster rate of uranium reduction in the presence of sulfate and no lag time until the onset of U reduction in contrast to U alone. This kinetics information can be used to design an SRB-dominated biotreatment scheme for the removal of U(VI) from an aqueous source.     

Campylobacter susceptibility to ciprofloxacin and corresponding fluoroquinolone concentrations within the gastrointestinal tracts of chickens

AIMS: This study evaluated the relationship between Campylobacter susceptibility and enteric fluoroquinolone concentrations in chickens treated with different doses of enrofloxacin. METHODS AND RESULTS: All chickens were challenged with seven fluoroquinolone sensitive Campylobacter jejuni (6.6 x 10(6) CFU per bird) at 2 weeks posthatch. At 26 days of age chickens were treated with 0 (n = 29 birds), 25 mg ml(-1) enrofloxacin (Baytril, Bayer Corp., Shawnee Mission, KS, USA) for 3 days (n = 45 birds) or 50 mg ml(-1) enrofloxacin for 7 days (n = 65 birds) in the drinking water. The crop, upper ileum, lower ileum, ceca and colon contents were collected from both enrofloxacin treatment groups (n = 5 birds per day per treatment group) and nonmedicated controls. The minimum inhibitory concentration (MIC) of ciprofloxacin for Campylobacter increased for isolates from both treatment groups within the first day of dosing and the daily average ranged from 1.4 to 6.5 microg ml(-1) throughout the study. Although enteric fluoroquinolone concentrations were higher (P < 0.05) in birds dosed with 50 mg ml(-1)vs 25 mg ml(-1) enrofloxacin, there were no differences between the isolates collected from these groups for MIC values. CONCLUSION: These data indicate, for the doses used, differences in gut fluoroquinolone concentrations do not produce isolates of Campylobacter with differing susceptibility to ciprofloxacin. SIGNIFICANCE AND IMPACT OF THE STUDY: Using the manufacturers lowest, shortest duration dose vs the highest, longest duration dose of enrofloxacin did not change Campylobacter susceptibility to ciprofloxacin. However, ciprofloxacin MIC values for Campylobacter determined in this study were lower than previously reported.     

Draw-fill batch culture mode for production of xylanases by <Emphasis Type="Italic">Cellulomonas flavigena</Emphasis> on sugar cane bagasse

Draw-fill culture was evaluated as a method for xylanase production by Cellulomonas flavigena on sugar cane bagasse. Specific xylanase activity and volumetric xylanase activities were measured by harvesting 50%, 55%, 60% and 70% of fermented broth at the end of each subculture. Maximum specific (64 IU mg(-1) protein) and volumetric (166 IU ml(-1)) xylanase activities were obtained by harvesting 50-55% of broth. Values were 3.4 and 3.8 times greater than those obtained in batch cultures carried out under the same conditions. Enzyme productivity of 4.2 IU ml(-1) h(-1) was significantly greater than that obtained in continuous cultures (2.4 IU ml(-1) h(-1)) (P<0.05).     

Nuclear maturation kinetics and in vitro embryo development of cattle oocytes prematured with butyrolactone I combined or not combined with roscovitine

Cyclin dependent kinase inhibitors (CDKIs) may be used for pre-maturation culture, but can accelerate nuclear maturation. The aim of the present research was to compare the effect of butyrolactone I (BLI) alone or combined with roscovitine (ROS) at lesser than typically used concentrations on nuclear maturation kinetics and embryo development. To assess maturation kinetics (Experiment 1), oocytes were cultured in 100 microM BLI (B) or 6.25 microM BLI+12.5 microM ROS (BR) in TCM-199 for 24 h. Oocytes were subsequently submitted to in vitro maturation (IVM) in TCM-199+0.5 microg/ml FSH, 50 microg/ml LH and 10% FCS for another 24 h, during which oocytes were fixed every 3 h. In Experiment 2, oocytes were submitted to 24h pre-maturation treatments, with the inhibitors being diluted in TCM-199 or DMEM. IVM lasted 21 h in the culture media DMEM+0.5 microg/ml FSH, 50 microg/ml LH, 5% FCS and 50 ng/ml EGF. After IVM, oocytes from all groups were fertilized in vitro. Oocytes and sperm (2x10(6) sperm cells/ml) were co-cultured for 18 h. Embryos were co-cultured with granulosa cells in CR2aa for 8 days. All cultures were in droplets under oil, at 38.5 degrees C and 5% CO2 in air. In both experiments, control oocytes (C) were submitted only to IVM. In Experiment 1, at 0 h, C and B oocytes were all (100%) at the germinal vesicle stage (GV) of development. BR had fewer GV oocytes (89%, P<0.05). After 3 h IVM, B and BR had fewer oocytes in GV (84.7 and 79.6%, P>0.05) than C (100%, P<0.05). At 12 h, most oocytes were at intermediate stages (metaphase to telophase I) in all groups (approximately 80%, P>0.05). After 21 (77-89%) and 24 h (85-95%), all groups had similar metaphase II (MII) rates of development (P>0.05). In Experiment 2, cleavage (79-84%, P>0.05) and Day 7 blastocyst rates (26-36%, P>0.05) were similar. After 8 days, the group pre-matured with BR in DMEM had lesser blastocyst rates of development (32.3%) lower than C (40.1%, P<0.05). The other groups were similar to C (35-38%, P>0.05). Hatching rates were similar (10-15%, P>0.05) as were total cell numbers (141-170). In conclusion, BR is less effective in maintaining meiosis block; B and BR accelerate meiosis resumption; and use of pre-maturation medium may affect developmental rates.     

Protective effect of aspartate and glutamate on cardiac mitochondrial function during myocardial infarction in experimental rats

The present study investigates the effect of aspartate and glutamate on mitochondrial function during myocardial infarction (MI) in wistar rats. Male albino wistar rats were pretreated with aspartate [100 mg(kgbody weight)(-1) day(-1)] or glutamate [100 mg(kg body weight)(-1) day(-1)] intraperitoneally for a period of 7 days. Following amino acid treatment, MI was induced in rats by subcutaneous injection of isoproterenol [200 mg(kg body weight)(-1) day(-1)] for 2 days at an interval of 24 h. Isoproterenol (ISO) induction resulting in significant (P<0.05) increase in the levels of cardiac mitochondrial lipid peroxidation with a decrease in reduced glutathione level. The activities of glutathione peroxidase and glutathione reductase were significantly (P<0.05) decreased by ISO. ISO-induction also caused significant (P<0.05) decrease in the activities of mitochondrial tricarboxylic acid cycle enzymes (malate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, alpha-ketoglutarate dehydrogenase) and respiratory chain enzymes (NADH dehydrogenase and cytochrome-c-oxidase). ISO significantly (P<0.05) reduced the cytochrome contents, ATP production, ADP/O ratio and oxidation of succinate in state 3/state 4 whereas significantly (P<0.05) increased NADH oxidation. Pretreatment with aspartate or glutamate significantly (P<0.05) reduced the alterations induced by ISO and maintained normal mitochondrial function. The present findings reveal the protective effect of aspartate and glutamate on cardiac mitochondrial function in myocardial infarction-induced rats.     

Fixed-time artificial insemination of postpartum beef cows at 72 or 80 h after treatment with the MGA Select protocol

The objective was to determine the appropriate timing of fixed-time artificial insemination (AI) following administration of the MGA Select protocol. Cows at two locations (Location 1, n=114; Location 2, n=97 ) were assigned to fixed-time AI at 72 or 80 h by age, body condition score (BCS), days postpartum (DPP), AI technician, and sire. All cows were synchronized with the MGA Select protocol, consisting of oral administration of melengestrol acetate (MGA; 0.5mg/hd per day) for 14 days, GnRH (Cysotrelin, 100 microg, i.m.; Day 26) 12 days after MGA withdrawal, followed in 7 days with PGF(2alpha) (PG; Lutalyse, 25mg i.m.; Day 33). Cows were inseminated at 72 h ( n=108 ) or 80 h ( n=103 ) after PG and GnRH (100 microg) was given at insemination. Location was not significant and, therefore, was removed from the model. Mean BCS ( 5.2+/-0.1, 72 h; 5.3+/-0.1, 80 h) and DPP ( 34+/-2, 72 h; 35+/-2, 80 h) did not differ ( P>0.1 ) between treatments. Serum progesterone concentrations 7 and 1 day prior to MGA were used to determine pre-treatment cyclicity: cows with at least one sample with progesterone > or =1 ng/ml were defined as cyclic (33/108, 31%, 72 h, versus 32/103, 31%, 80 h; P>0.1). Cows with serum progesterone concentrations > or =1 ng/ml on the day of PG were defined as responding to the synchronization protocol (74/108 (69%), 72 h versus 69/103 (67%), 80 h; P>0.1 ). Although pregnancy rates were higher ( P<0.05 ) for cows inseminated at 72 h (69/108, 64%) versus 80 h (52/103, 50%) after PG, pregnancy rates at the end of the breeding season did not differ ( P>0.1 ) between treatments (98/108 (91%), 72 h; 88/103 (85%), 80 h). In conclusion, pregnancy rates were higher when postpartum beef cows synchronized with the MGA Select protocol were inseminated at 72 h versus 80 h after PG.     

Methyl tert-butyl ether (MTBE) degradation by a microbial consortium

The widespread use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in a large number of cases of groundwater contamination. Bioremediation is often proposed as the most promising alternative after treatment. However, MTBE biodegradation appears to be quite different from the biodegradation of usual gasoline contaminants such as benzene, toluene, ethyl benzene and xylene (BTEX). In the present paper, the characteristics of a consortium degrading MTBE in liquid cultures are presented and discussed. MTBE degradation rate was fast and followed zero order kinetics when added at 100 mg l(-1). The residual MTBE concentration in batch degradation experiments ranged from below the detection limit (1 microg l(-1)) to 50 microg l(-1). The specific activity of the consortium ranged from 7 to 52 mgMTBE g(dw)(-1) h(-1) (i.e. 19-141 mgCOD g(dw) (-1) h(-1)). Radioisotope experiments showed that 79% of the carbon-MTBE was converted to carbon-carbon dioxide. The consortium was also capable of degrading a variety of hydrocarbons, including tert-butyl alcohol (TBA), tert-amyl methyl ether (TAME) and gasoline constituents such as benzene, toluene, ethylbenzene and xylene (BTEX). The consortium was also characterized by a very slow growth rate (0.1 d(-1)), a low overall biomass yield (0.11 gdw g(-1)MTBE; i.e. 0.040 gdw gCOD(-1)), a high affinity for MTBE and a low affinity for oxygen, which may be a reason for the slow or absence of MTBE biodegradation in situ. Still, the results presented here show promising perspectives for engineering the in situ bioremediation of MTBE.