Hemocyanin lipid uptake in Polybetes pythagoricus is altered by fenitrothion

The spider very high density lipoprotein (VHDL), which contains hemocyanin as the major apoprotein, transports most of the circulating lipids. In this work, the effect of the pesticide fenitrothion (FS) on the ability of VHDL-apoproteins to uptake different lipids was investigated. For this, VHDL was delipidated using Triton X-100 and recombined with different radiolabeled lipids in the presence or the absence of FS. The oligomeric structural integrity was maintained after delipidation as shown by non-denaturating PAGE. In the presence of the insecticide, palmitic acid uptake decreased by 28.2 and 62.4% after treating the apolipoprotein with 10 and 20 ppm FS, respectively. Decreases in the uptake of cholesterol, triolein, and phosphatidylcholine caused by FS were 29, 23, and 31% using 10 ppm, and 40, 44, and 29% using 20 ppm FS, respectively. Fluorescence measurements with the hydrophobic probes diphenylhexatriene (DPH) and diphenylhexatrienyl-propionic acid (DPH-PA) indicate that FS induces a red shift, decreases the intensity and increases the anisotropy of the emission of these probes in the VHDL. These results indicate that insecticide binding to the lipoprotein enhances the environment polarity and restricts the mobility of these probes at their binding site. These changes at the hydrophobic VHDL binding sites could lead to the decreased affinity for lipids and hydrophobic ligands. It is inferred that FS could alter the normal lipid exchange between this lipoprotein and tissues.     

Quantitative modification of the testicular structure in pigs fed with anabolic doses of clenbuterol

Morphological and structural data of the testes of thirty male pigs were recorded in order to evaluate the effects of an anabolic clenbuterol treatment. Pigs aged 6 months were randomly allocated to one of three experimental groups. In two treated groups, the animals were fed with anabolic doses of clenbuterol (1 ppm); in the CLB group (n = 10) clenbuterol was given until they were slaughtered (treatment period = 3 months) whereas in the CLBW group (n = 10) the clenbuterol was withdrawn two weeks before slaughter (treatment period = 2.5 months); clenbuterol was not given to the pigs of the control group (n = 10). Stereological estimations of the tissular volume fraction and tubular volume density were applied to quantify the structural constituents of the testes. The results showed an increased volume fraction of the testicular interstitium especially in the Leydig cell population, as a result of the clenbuterol treatment. The increase in the nuclear volume fraction of the Leydig cells was the more persistent change in the variations recorded in both treated groups with respect to the control. A regression of the seminal epithelium was also recorded in the treated animals. The rest of the structural parameters were closer to the normal figures in the CLBW group, suggesting a recovery of the testicular structure when clenbuterol was withdrawn.     

Pharmacokinetics of an ampicillin-sulbactam combination after intravenous and intramuscular administration to neonatal calves

The pharmacokinetics of a 2:1 ampicillin-sulbactam combination after intravenous (i.v.) and intramuscular (i.m.) injection at a single dose rate of 20 mg/kg bodyweight (13.33 mg/kg of sodium ampicillin and 6.67 mg/kg of sodium sulbactam) were studied in 10-day-old neonatal calves (n = 10). The plasma concentration-time data of both antibiotics were best fitted to an open two-compartment model after i.v. administration. After i.m. administration, an open two-compartment model demonstrated first order absorption. The apparent volumes of distribution of ampicillin and sulbactam, calculated by the area method, were 0.20+/-0.01 and 0.18+/-0.01 L/kg, respectively, and the total body clearances were 0.51+/-0.03 and 0.21+/-0.01 L/kg h. The elimination half-lives of ampicillin after i.v. and i.m. administration were 0.99+/-0.03 and 1.01+/-0.02 h, respectively, whereas for sulbactam the half-lives were 2.24+/-0.02 and 3.44+/-0.94 h. The bioavailability after i.m. injection was high and similar for both drugs (70.31+/-0.2% for ampicillin and 68.62+/-4.44% for sulbactam). The mean peak plasma concentrations of ampicillin and sulbactam were reached at similar times (0.47+/-0.02 and 0.72+/-0.01 h, respectively) and peak concentrations were also similar but not proportional to the dose administered (17.88+/-0.91 mg/L of ampicillin and 12.92+/-0.79 mg/L of sulbactam). Both drugs had similar pharmacokinetic behaviour after i.m. administration. Since the plasma concentrations of sulbactam were consistently higher during the elimination phase of their disposition, consideration could be given to formulating the ampicillin-sulbactam combination in a ratio higher than 2:1.     

Analysis of Aggressiveness of Erwinia amylovora Using Disease-Dose and Time Relationships

ABSTRACT The aggressiveness of an extensive collection of strains of Erwinia amylovora was analyzed using immature fruit and detached pear flower assays under controlled environmental conditions. The analysis was performed by means of a quantitative approach based on fitting data to mathematical models that relate infection incidence to pathogen dose and time. Probit and hyperbolic saturation models were used for disease-dose relationships and provided information on the median effective dose (ED(50)). Values of ED(50) ranged from 10(3) to 10(6) CFU/ml (10 to 10(4) CFU per site of inoculation). A modified Gompertz model was used for disease-time relationships and provided information on the rate of infection incidence progression (r(g)) and time delayed to start of the incidence progress curve (t(0)). Values of r(g) ranged from near 0 to 1.90, and t(0) varied from 1.3 to more than 10 days. The more aggressive strains showed high r(g), low ED(50) values, and short t(0), whereas the less aggressive strains showed low r(g), high ED(50), and long t (0). The aggressiveness was dependent on plant material type and pear cultivars and was significantly different between strains of E. amylovora. Infectivity titration and kinetic analysis of progression of incidence of infections using the immature pear test and a standardized scale are proposed for assessment of strain aggressiveness. The implications of r(g), ED(50), and t(0) for the epidemiology and management of fire blight are discussed, particularly the wide range of aggressiveness among strains, the degree of host specificity observed in pear isolates, the very high infective potential of this pathogen, the independent action of pathogen cells during infection, and the possible advantage of including aggressiveness parameters into fire blight risk forecasting systems.     

Andalasin A, a new stilbene dimer from Morus macroura

A new stilbene dimer, andalasin A (1), together with the known stilbene oxyresveratrol and the 2-arylbenzofuran glycoside mulberroside C, have been isolated from the wood of Morus macroura. The structure of the new compound was elucidated on the basis of spectroscopic data. Compound 1 shows weak antinematodal and moderate antifungal properties.     

Tiliroside and gnaphaliin inhibit human low density lipoprotein oxidation

Two flavonoids, gnaphaliin and tiliroside, isolated from Helichrysum italicum, were studied in vitro for their capacity to inhibit Cu(2+)-induced human low density lipoprotein (LDL) and diluted plasma oxidation. LDL oxidation was monitored by conjugated diene, thiobarbituric acid-reactive substances (TBARS) formation and electrophoretic mobility on agarose gel. Gnaphaliin and tiliroside increased the lag-phase for diene conjugate production in a dose-dependent manner. The reduction of TBARS production confirmed the antioxidant activity of gnaphaliin and tiliroside with 50% inhibitory concentration (IC(50)) values of 8.0+/-3.9 microM and 7.0+/-2.6 microM respectively. Furthermore, the flavonoids negated the Cu(2+)-induced increase in electrophoretic mobility of LDL. Antioxidant activity of gnaphaliin and tiliroside was significantly different when diluted plasma was oxidised by adding 1 mM CuSO(4). Although both flavonoids again reduced the TBARS production, tiliroside showed higher activity than gnaphaliin (IC(50)=10.6+/-2.5 microM vs. IC(50)>50 microM). In conclusion, tiliroside and gnaphaliin are antioxidants against in vitro Cu(2+)-induced LDL oxidation in the same order of magnitude compared to that of the reference drug, probucol.     

Harmonised pesticide risk trend indicator for food (HAPERITIF): The methodological approach

To provide a harmonised European approach for pesticide risk indicators, the Sixth EU Framework Programme recently financed the HAIR (HArmonised environmental Indicators for pesticide Risk) project. This paper illustrates the methodology underlying a new indicator-HAPERITIF (HArmonised PEsticide RIsk Trend Indicator for Food), developed in HAIR, for tracking acute and chronic pesticide risk trends for consumers. The acute indicator, HAPERITIF(ac), is based on the ratio between an estimated short-term intake (ESTI), calculated as recommended by the World Health Organisation (WHO), and the acute reference dose (ARfD); the chronic indicator HAPERITIF(chr) is based on the ratio between an estimated daily intake (EDI) and the admissible daily intake (ADI). HAPERITIF can be applied at different levels of aggregation. Each level gives information for proper risk management of pesticides to reduce the risk associated with food consumption. An example of application using realistic scenarios of pesticide treatments on a potato crop in central-northern Italy is reported to illustrate the different steps of HAPERITIF.     

Relevance of ovarian follicular development to the seasonal impairment of fertility in weaned sows

A field study was conducted to estimate seasonal differences in follicular development in weaned sows and to evaluate the implication of these differences on seasonal infertility. A total of 110 sows were selected at weaning during winter–spring (WS, n = 58) and summer–autumn (SA, n = 52). Ovaries were scanned once daily from weaning to the onset of oestrus and twice daily from then until ovulation. Six sows during WS were removed from study for not showing growing follicles at weaning. Oestrus was evaluated twice daily from day 1 after weaning to day 14 post-weaning. One of 52 (1.9%) sows in WS and 9/52 (17.3%) in SA showed no signs of oestrus within 14 days of weaning (P < 0.05). The diameters of the follicles at weaning, at the onset of oestrus and just before ovulation were smaller (P < 0.01) in SA sows than in WS sows. There were fewer follicles in SA sows than in WS sows just before ovulation (P < 0.05). Fifty of 51 (98.0%) sows in WS and 31/43 (72.1%) sows in SA experienced a weaning-to-oestrus interval (WOI) of 3–6 days (P < 0.05). Fifty-one of 52 (98.1%) sows in WS and 43/52 (82.7%) sows in SA were inseminated; the percentage of pregnant sows that failed to farrow was lower in WS (1/51, 2.0%) than in SA (5/43, 11.6%; P < 0.05). The percentage of farrowed sows was greater in WS (46/51, 90.2%) than in SA (32/43, 74.4%; P < 0.05). Sows in WS had on average 1.5 more piglets than sows in SA (P < 0.05). Sows with a WOI of 3–6 days had lower rates of pregnancy losses (P < 0.05) and higher farrowing percentages (P < 0.01) than those with a WOI > 6 days, irrespective of season.     

Calorie restriction promotes mitochondrial biogenesis by inducing the expression of eNOS

Calorie restriction extends life span in organisms ranging from yeast to mammals. Here, we report that calorie restriction for either 3 or 12 months induced endothelial nitric oxide synthase (eNOS) expression and 3',5'-cyclic guanosine monophosphate formation in various tissues of male mice. This was accompanied by mitochondrial biogenesis, with increased oxygen consumption and adenosine triphosphate production, and an enhanced expression of sirtuin 1. These effects were strongly attenuated in eNOS null-mutant mice. Thus, nitric oxide plays a fundamental role in the processes induced by calorie restriction and may be involved in the extension of life span in mammals.