Extraparticulate chain interaction between different electron transport particles

Interaction or cross-linking between the respiratory chains of the electron transport particles of bacterial origin occurs with a mixture of active and inactive particles. Interaction between bacterial particles and liver sub-mitochondrial particles also occurs. Irradiation of the bacterial particles at 360 nanometers resulted in the destruction of quinone and consequent loss of ability of reduced nicotinamide adenine, dinucleotides to reduce cytochromes b, c(1), c, and a plus a(3). A mixture of both irradiated and untreated particles in the presence of the reduced dinucleotide resulted in the reduction of cytochromes c and a plus a(3), in an amount equivalent to the total concentration of these cytochromes in both types of particles. In contrast, the amount of cytochrome b reduced was equivalent to half the particle concentration or to that observed with the active particles alone. The rate of reduction of cytochromes c and a plus a(3) with the mixture of particles was similar to that with the active particles alone. The interaction or cross-linking between the particulate respiratory chains of bacteria or of bacterial and mammalian systems occurs after cytochrome b and before or at cytochrome c.     

Winter outbreaks of laminitis in dairy calves: aetiology and laboratory, radiological and pathological findings.

During the winter months of 1984 to 1989, outbreaks of laminitis occurred in up to 6 per cent of all the dairy calves aged four to six months on a dairy farm in a village in Israel. The clinical signs were reluctance to move, an arched back, overgrown hooves, supracoronary swelling and occasional walking on the carpus; most of the calves were unthrifty. Owing to the regular recurrence of the disease, the feeding and haematological, radiological and pathological changes in both the affected and normal calves at the farm, and in normal calves at another farm in the same village were studied. In the affected calves there were significant increases in serum protein concentration and in the activities of creatine phosphotinase and gamma-glutamyltransferase. Radiography showed dilated PIII vascular channels and some PIII rotation. Post mortem studies revealed haemorrhages in the laminar section of the hoof. The management of the farms differed in the protein level of the milk replacer and the 'starter' diet used during the first few months. The affected farm used feeds containing 18 per cent digestible protein whereas the unaffected farm used feeds containing 15.3 per cent digestible protein.     

Experimental handling stress as infection-facilitating factor for the goldfish ulcerative disease

Experimental handling stress (EHS) was applied to clinically asymptomatic farmed goldfish (Carassius auratus L.). EHS affected the gills and skin integrity of the fish and was accompanied by increased levels of plasma glucose, cortisol and interleukin-10 (IL-10). EHS application was followed by highly significant enhancement of the rate of infection with a virulent Aeromonas salmonicida isolate. Cumulative ulceration at the initial phase of the ensuing goldfish ulcerative disease (GUD) evidenced a facilitating role of EHS in the onset of GUD. Host susceptibility to the pathogen increased from 40% in unstressed fish to 90% in the stressed fish. A. salmonicida could be reisolated from the early-stage skin lesions only, whereas opportunistic strains, other than A. salmonicida (A. sobria and A. hydrophila), were recovered from progressive-stage ulcers. The implication of these findings in fish aquaculture is discussed.     

Spin-polarized light-emitting diode based on an organic bipolar spin valve

The spin-polarized organic light-emitting diode (spin-OLED) has been a long-sought device within the field of organic spintronics. We designed, fabricated, and studied a spin-OLED with ferromagnetic electrodes that acts as a bipolar organic spin valve (OSV), based on a deuterated derivative of poly(phenylene-vinylene) with small hyperfine interaction. In the double-injection limit, the device shows ~1% spin valve magneto-electroluminescence (MEL) response, which follows the ferromagnetic electrode coercive fields and originates from the bipolar spin-polarized space charge-limited current. In stark contrast to the response properties of homopolar OSV devices, the MEL response in the double-injection device is practically independent of bias voltage, and its temperature dependence follows that of the ferromagnetic electrode magnetization. Our findings provide a pathway for organic displays controlled by external magnetic fields.     

Pharmacokinetic changes of several antibiotics in chickens during induced fatty liver

The concentrations of five antibiotics (erythromycin, lincomycin, penicillin G, streptomycin and oxytetracycline) were determined in chicken serum before and after induced fatty liver. The pharmacokinetic variables were calculated according to the obtained data. The crossover trial design involved 10 chickens for each antibiotic. The fatty liver was produced by oestradiol-dipropionate injections and monitored by serum malic enzyme activity determinations. Protein binding of the respective antibiotics was determined in vitro in the serum obtained from normal and oestrogen-treated birds. Induction of fatty liver caused several changes in the determined variables. The measured peak concentrations were higher for lincomycin and erythromycin and lower for penicillin and oxytetracycline while streptomycin remained unchanged. The peak concentration of streptomycin appeared earlier and the peak of oxytetracycline later than in the normal chickens. The elimination half-lives were shorter for erythromycin, lincomycin and streptomycin and increased for penicillin and oxytetracycline. The area under the concentration curve (AUC) decreased for erythromycin, penicillin and streptomycin, increased for oxytetracycline and remained unchanged for lincomycin. The body clearance (ClB/f) and the apparent specific volume of distribution (Vd(area'/f) were considerably changed in association with fatty liver induction. Since the fraction of the drug absorbed (f) is not known, it can only be speculated that changes in distribution rather than reduced liver function altered the kinetics. The protein binding was decreased for all the antibiotics, but this did not seem to be the reason for changes in kinetics, except perhaps in the case of penicillin.     

The potential of transforming simple structured pine plantations into mixed Mediterranean forests through natural regeneration along a rainfall gradient

The aim was to study the potential for using natural regeneration as a basis for transformation of simply structured conifer plantations into mixed Mediterranean forests. We studied the variation along a rainfall gradient, in the natural regeneration of tree species in the understory of planted 40- to 50-year-old Aleppo pine (Pinus halepensis) forests. The study was conducted within the Mediterranean zone of Israel, which extends from the semiarid northern Negev desert (rainfall ca. 300 mm yr⁻¹) in the south to the humid Upper Galilee in the north (ca 900 mm yr⁻¹). Cover and height, density, and species composition of regenerating trees were measured on south- and north-facing slopes in forest sites of comparable silvicultural history (site preparation methodology, planting density and thinning regime) distributed along the rainfall gradient. Altogether, 12 species of regenerating native broadleaved trees were found in the understory of the various forest sites. Surface cover, density and species richness increased linearly along the entire rainfall gradient, on both north- and south-facing slopes, ranging from zero in the driest forest sites up to 85% cover, 7980 trees ha⁻¹ and 4.5 species per 200 m², respectively, in the most humid ones. Species composition of regenerating trees was also related to rainfall amount, through changes in the relative importance of species along the rainfall gradient. The effect of topographic aspect on tree regeneration was inconsistent, i.e., the interaction Rainfall × Aspect was significant. Nevertheless, the general trend showed better regeneration on north-facing slopes. Most of the regenerating trees in the understory were small, i.e., less than 100 cm in height, with no clear effect of rainfall amount and topographic aspect on the relative abundance of height classes. Regeneration by Aleppo pine was highly variable among and within the different forest sites and ranged from 0 to 1565 trees ha⁻¹, with no clear relationships with rainfall amount and topographic aspect. In light of our results we propose that the future structure of forests should vary with respect to annual rainfall amount within possible silvicultural scenarios.     

Monitoring the behavior of hypoxia-stressed Carassius auratus using computer vision

Behavioral variations of a school of fish (Carrasius auratus) in a tank were monitored using computerized vision while the fish were subjected to hypoxia stress conditions. Two video cameras viewed the tank, one from the side through a transparent wall and one from above. The images were processed by a PC-based image processing algorithm which provided three coordinates of the school's center of gravity, with the standard deviations of each coordinate, and the projected spatial distribution of the fish. Stressed fish differed from controls with the following behavioral responses: (i) the center of gravity moved upwards and horizontally away from the transparent wall; (ii) swimming speed was apparently reduced; (iii) there were strong fluctuations in all three directions associated with spreading and contracting of the school; (iv) the periodic amplitude of the motion in the vertical direction increased. This study might evolve into an automatic stress warning technique for fish farms, based on alterations in the behavior of fish when stressed.