Comparison of Worm Control Strategies in Grazing Sheep in Denmark

Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed.     

Effect of potassium sorbate,sodium benzoate,and sodium nitrite on biosynthesis of cyclopiazonic and mycophenolic acids and citrinin by fungi of the <Emphasis Type="Italic">Penicillium</Emphasis> genus

The effect of potassium sorbate, sodium benzoate, and sodium nitrite used as preservatives in the food industry in the production of such mytotoxins as citrinin cyclopiazonic and mycophenolic acids by the contaminating fungi Penicillium citrinum, P. commune, and P. brevicompactum, respectively, was investigated. It was shown that the effect of preservatives used at concentrations relevant to the food industry on the synthesis of mycotoxins depended on the species-specific biochemical and physiological features of the cultures. The growth of P. brevicompactum was inhibited to the highest degree by sodium nitrite and potassium sorbate, and the growth of P. commune was so inhibited by sodium benzoate. It was established that the introduction of 0.015% sodium nitrite into the medium resulted in 1.3- and 1.4-fold reductions of the production of citrinin and mycophenolic acid, respectively, while the production of cyclopiazonic acid did not change in comparison with the control. The introduction of 0.015% sodium benzoate caused a more than 1.5-fold increase of the concentration of citrinin, cyclopiazonic, and mycophenolic acids, and the addition of 0.02% potassium sorbate increased the production of cyclopiazonic and mycophenolic acids by 1.7 and 2.6 times, respectively.     

13C tracer experiments and metabolite balancing for metabolic flux analysis: comparing two approaches

Conventional metabolic flux analysis uses the information gained from determination of measurable fluxes and a steady-state assumption for intracellular metabolites to calculate the metabolic fluxes in a given metabolic network. The determination of intracellular fluxes depends heavily on the correctness of the assumed stoichiometry including the presence of all reactions with a noticeable impact on the model metabolite balances. Determination of fluxes in complex metabolic networks often requires the inclusion of NADH and NADPH balances, which are subject to controversial debate. Transhydrogenation reactions that transfer reduction equivalents from NADH to NADPH or vice versa can usually not be included in the stoichiometric model, because they result in singularities in the stoichiometric matrix. However, it is the NADPH balance that, to a large extent, determines the calculated flux through the pentose phosphate pathway. Hence, wrong assumptions on the presence or activity of transhydrogenation reactions will result in wrong estimations of the intracellular flux distribution. Using 13C tracer experiments and NMR analysis, flux analysis can be performed on the basis of only well established stoichiometric equations and measurements of the labeling state of intracellular metabolites. Neither NADH/NADPH balancing nor assumptions on energy yields need to be included to determine the intracellular fluxes. Because metabolite balancing methods and the use of 13C labeling measurements are two different approaches to the determination of intracellular fluxes, both methods can be used to verify each other or to discuss the origin and significance of deviations in the results. Flux analysis based entirely on metabolite balancing and flux analysis, including labeling information, have been performed independently for a wild-type strain of Aspergillus oryzae producing alpha-amylase. Two different nitrogen sources, NH4+ and NO3-, have been used to investigate the influence of the NADPH requirements on the intracellular flux distribution. The two different approaches to the calculation of fluxes are compared and deviations in the results are discussed. Copyright 1998 John Wiley & Sons, Inc.     

Effect of SWF-radiation on thrombocytes and erythrocyte functions of albino rats upon stress condition

With the help of a specially designed generator, we have investigated the effect of electromagnetic SWF-oscillation, at nitric oxide molecular spectrum of radiation and absorption, on the function of thrombocytes and erythrocytes of albino rats in the state of immobilizing stress. 5, 15 and 30 min long SWF-radiation treatments were demonstrated to foster various degrees of restoration of thrombocyte and erythrocyte function, the efficiency depending on the period of radiation. It was after a 30 min radiation of rats that a most expressed restoration of thrombocyte and erythrocyte functional activity was observed.     

The Fungus <Emphasis Type="Italic">Penicillium citrinum</Emphasis>, Isolated from Permafrost Sediments,as a Producer of Ergot Alkaloids and New Quinoline Alkaloids Quinocitrinines

Quinocitrinines and ergot alkaloids were synthesized by the strain Penicillium citrinum VKM FW-800 as the culture grews. The major part of these secondary metabolites was secreted into the medium. In the phase of growth deceleration, these metabolites were partly absorbed by the producer cells. Zinc ions stimulated both the primary and secondary metabolic processes. Addition of this microelement into the culture medium stimulated biomass accumulation and the synthesis of clavine alkaloids and quinocitrinines.     

Penicillium expansum, a resident fungal strain of the orbital complex Mir, producing xanthocillin X and questiomycin A

It was demonstrated that the fungus Penicillium expansum 2-7, a resident strain of the orbital complex Mir, which became dominating at the end of a long-term space flight, formed biologically active secondary metabolites (antibiotics). Using physicochemical methods, these metabolites were identified as xanthocyllin X and questiomycin A. Time courses of their biosyntheses during growth and development of the producer culture were studied. Addition of zinc to the culture medium affected both the growth of the culture and the biosyntheses of the antibiotics. The concentrations of zinc in the medium, optimum for xanthocyllin X and questiomycin A production, amount to 0.3 and 3.0 mg/l, respectively.     

Exometabolites of the fungal isolates (Genus <Emphasis Type="Italic">Penicillium</Emphasis>, Section <Emphasis Type="Italic">Chrysogena</Emphasis>) from low-temperature ecotopes

Exometabolites of 22 strains of the genus Penicillium, section Chrysogena isolated from low-temperature ecotopes of various geographical regions were analyzed. The ecotopes included permafrost deposits, frozen volcanic ash, a fossil horse, cryopeg, and water from an Antarctic lake. The studied strains were found to contain exometabolites belonging to the groups of penicillins (penicillin G), chrysogines (chrysogine, 3-acetyl-quinazolin-4(3H)-one, 2-pyruvoylaminobenzamide, 2-(2-hydroxypropionylamino)-benzamide, and questiomycin A), roquefortines (3,12-dihydroroquefortine, roquefortine, glandicolines A and B, and meleagrine), xanthocillins (xanthocillin X), and simple tryptophan derivatives (N-acetyltriptamine and indoleacetic acid). In five P. chrysogenum strains and three P. nalgiovense strains, a correlation was found between exometabolite spectra and morphological characteristics of the cultures isolated from modern ecotopes. For other strains species, identification was based on morphological features due to the absence of biosynthesis of penicillin G on the major chemotaxonomic markers for these species.     

Population parameters and exploitation rate of Sarotherodon galilaeus galilaeus (Cichlidae) in Lakes Doukon and Togbadji,Benin

Growth, mortality, recruitment and relative yield per recruit of Sarotherodon galilaeus galilaeus from Lakes Doukon and Togbadji were studied. Data on total length, total weight and sex were recorded on a monthly basis between January and December 2013 for S. g. galilaeus captured by local fishers. The estimated asymptotic lengths L_∞ were 26.2 and 23.6?cm for Lakes Doukon and Togbadji, respectively, while the growth rate K was 0.73 in Lake Doukon and 0.87 in Lake Togbadji. Estimates of fishing mortality, 0.27 and 0.47 y^?1 for Doukon and Togbadji, respectively, were low relative to natural mortality, 1.51 and 1.74 y^?1, respectively. Sizes at first sexual maturity were 12.8 and 13.2?cm for females and males, respectively, in Lake Doukon, and 11.5 and 12.4?cm for females and males, respectively, in Lake Togbadji. The size at first capture was estimated at 13.3 and 12.7?cm for Lakes Doukon and Togbadji, respectively, which, in the light of the size at maturity estimates, indicates that fish spawn at least once before capture. The current exploitation rates of 0.15 for Lake Doukon and 0.21 for Lake Togbadji suggest that their stocks of S. g. galilaeus are not overexploited in either lake.