The relationship between flesh quality and numbers of Kudoa thyrsites plasmodia and spores in farmed Atlantic salmon, Salmo salar L

Atlantic salmon, Salmo salar L., were exposed to Kudoa thyrsites (Myxozoa, Myxosporea)-containing sea water for 15 months, and then harvested and assessed for parasite burden and fillet quality. At harvest, parasites were enumerated in muscle samples from a variety of somatic and opercular sites, and mean counts were determined for each fish. After 6 days storage at 4 degrees C, fillet quality was determined by visual assessment and by analysis of muscle firmness using a texture analyzer. Fillet quality could best be predicted by determining mean parasite numbers and spore counts in all eight tissue samples (somatic and opercular) or in four fillet samples, as the counts from opercular samples alone showed greater variability and thus decreased reliability. The variability in both plasmodia and spore numbers between tissue samples taken from an individual fish indicated that the parasites were not uniformly distributed in the somatic musculature. Therefore, to best predict the probable level of fillet degradation caused by K. thyrsites infections, multiple samples must be taken from each fish. If this is performed, a mean plasmodia count of 0.3 mm(-2) or a mean spore count of 4.0 x 10(5) g(-1) of tissue are the levels where the probability of severe myoliquefaction becomes a significant risk.     

Antioxidant and Anti-Inflammatory Activities of Barettin

In this paper, we present novel bioactivity for barettin isolated from the marine sponge Geodia barretti. We found that barettin showed strong antioxidant activity in biochemical assays as well as in a lipid peroxidation cell assay. A de-brominated synthetic analogue of barettin did not show the same activity in the antioxidant cell assay, indicating that bromine is important for cellular activity. Barettin was also able to inhibit the secretion of the inflammatory cytokines IL-1β and TNFα from LPS-stimulated THP-1 cells. This combination of anti-inflammatory and antioxidant activities could indicate that barettin has an atheroprotective effect and may therefore be an interesting product to prevent development of atherosclerosis.     

Histidine and carnosine reduce muscle fatigue in Xenopus laevis

The inclusion of either histidine or carnosine in a frog Ringer’s perfusate at a concentration of 20 mmol/dm³ reduced fatigue in the gastrocnemius muscle ofXenopus laevis significantly. Histidine was superior to carnosine in this respect. The evidence also suggests that muscles perfused with histidine exhibit superior recovery, accumulate less lactic acid and lose significantly less K⁺ from the intracellular fluid. The implications of these findings in future research on capture myopathy are discussed.     

A standard set of host differentials and unified nomenclature for an international collection of Diplocarpon rosae races

Black spot of rose is distributed throughout the world and is the most serious disease of roses (Rosa spp.) in the outdoor landscape. Resistance breeding has been frustrated by the occurrence of races of the causal pathogen Diplocarpon rosae. Races from Germany, North America and the UK have been characterized and maintained in a pathogenic state. However, these races were characterized using independent sets of host genotypes and are referenced using different nomenclatures. In the present study, a total of 15 D. rosae isolates from these locations, as well as Belgium and Italy, were inoculated to a common set of 15 rose cultivars in replicated, detached leaf trials. Baby Love^TM (cv. Scrivluv) was resistant to all isolates except for one originating from the UK. The rose cultivars Mrs Doreen Pike (Ausdor) and Hansa were resistant to all isolates except for one originating from Minnesota, USA. No rose genotype was universally susceptible. A total of 11 pathogenic races were differentiated based on their unique host ranges and were assigned an international race nomenclature. Nine cultivars are proposed as the first standard set of differential genotypes for characterization of D. rosae races.     

New insights into the genetics of EBLV-1 from Germany

Previous epidemiological studies on EBLVs indicated a distinct geographical distribution of EBLV-1 in Germany. In this study, 48 isolates were selected to further investigate the spatial and temporal distribution of EBLV-1 variants in Germany. The nucleoprotein-gene (N), the nucleoprotein-phosphoprotein spanning untranslated region (NP-UTR) and the UTR between G- and L-gene of each isolate were sequenced using direct cycle sequencing. Results of the subsequent phylogenetic analysis of the N-gene confirmed previous studies on EBLVs, showing a high sequence identity among German EBLV-1a isolates, and a correlation between genetic and temporal and spatial distance, respectively, was shown. Our results indicate that the GL-UTR is not suitable for phylogenetic analyses. Interestingly, 6 nt insertions in two isolates as well as a single nucleotide insertion in a different isolate were detected in the N-P UTR. Within the UTR between G- and L-gene one isolate showed a 35 nt deletion. The effect of those changes on viral properties remains elusive as such mutations have not been described for lyssaviruses before.     

Effects of dietary supplementation with an organic source of selenium on characteristics of semen quality and in vitro fertility in boars

Semen characteristics in boars fed organic or inorganic sources of Se were assessed in 3 experiments. Crossbred boars were randomly assigned at weaning to 1 of 3 dietary treatments: I) basal diets with no supplemental Se (control), II) basal diets with 0.3 mg/kg of supplemental Se from an organic source (Sel-Plex, Alltech Inc., Nicholasville, KY), and III) basal diets supplemented with 0.3 mg/kg of supplemental Se from sodium selenite (Premium Selenium 270, North American Nutrition Co. Inc., Lewisburg, OH). For Exp. 1, semen was collected from boars (n = 10/dietary treatment) on 5 consecutive days at 15 mo of age. Effects of treatment × day were detected for the proportions of progressively motile (P = 0.02) and rapidly moving (P = 0.03) spermatozoa, and measures of sperm velocity, including path velocity of the smoothed cell path (P = 0.05) and average velocity measured in a straight line from the beginning to the end of the track (P = 0.05). Negative effects of day of semen collection on sperm motility were least pronounced in boars fed Sel-Plex. Experiment 2 was conducted when boars were 17 mo of age, and semen was collected (n = 10 boars/dietary treatment), diluted in commercially available extenders, and stored at 18°C for 9 d. Effects of treatment × day were detected for percentages of motile (P = 0.01) and static (P = 0.01) spermatozoa, amplitude of lateral head displacement (P = 0.02), frequency with which the sperm track crossed the sperm path (P = 0.04), straightness (P = 0.01), and average size of all sperm heads (P = 0.03). In general, sperm cells from boars fed Sel-Plex were better able to maintain motility during liquid storage compared with boars fed sodium selenite. For Exp. 3, semen was collected from boars (n = 6/dietary treatment) at 23 mo of age, and spermatozoa were evaluated at d 1 and 8 after semen collection using in vitro fertilization procedures. There was a tendency for an effect (P = 0.11) of dietary treatment on fertilization rate with Sel-Plex-fed boars having the greatest value (70.7%). The results of this study suggest that there are positive effects of dietary supplementation with Sel-Plex on boar semen characteristics and that organic Se supplementation may help ameliorate the negative effects of semen storage on characteristics of sperm motility.     

Variability associated with the official USDA sampling plan used to inspect export wheat shipments for Tilletia controversa spores

The variability associated with estimating the true concentration of teliospores of dwarf bunt ( Tilletia controversa ) per 50 g of wheat (TC concentration) in an export wheat shipment was studied by measuring the TC concentration in 16 test samples (50 g) taken from each of 137 export shipments. The variability among the 16 TC test sample results, as measured by the standard deviation, was found to increase with TC concentration. The functional relationship was approximately linear in a full-log plot and regression analysis was used to determine the coefficients of the regression equation. Using statistical theory, the regression equation was modified to predict the standard deviation among test sample sizes other than the 50 g size used in this study. The standard deviation and coefficient of variation associated with using a 50 g test sample to estimate the true TC concentration of a wheat shipment with 2000 spores per 50 g were estimated to be 1062·8 and 53·1%, respectively. Increasing test sample size to 1600 g reduced the standard deviation and coefficient of variation to 187·9 and 9·4%, respectively.     

Participatory technology development in agroforestry: methods from a pilot project in Zimbabwe

An on-farm agroforestry pilot project was initiated by the Zimbabwe Forestry Commission in 1988. The main objective of the project is to investigate a range of options to solve problems of woodland depletion faced by small-scale farmers. This paper describes the first two years of on-farm experimentation. The first season's trials are described, and the rationale for moving towards an approach of greater farmer participation in the research process is given. Steps taken to promote experimental tree planting on farms are described, and methods used are illustrated by examples from the project. Critical awareness-raising techniques, steamming from Freirian philosophy, have been central to the methods. The need for a partnership between formal and informal farmer-based research is discussed, as is a model for agroforestry research and development. The latter is proposed in a way that formal research develops the components of agroforestry practices, whilst farmers are encouraged to experiment with a combination of these components in order to develop practices appropriate to local conditions.