Haematological and biochemical investigations of diseased koalas (Phascolarctos cinereus)

Haematological and biochemical investigations were performed on 14 koalas with uncomplicated cystitis, 8 with complicated cystitis, 8 with conjunctivitis, 8 with lymphosarcoma, and 14 with miscellaneous diseases. Changes were limited and inconsistent in individual koalas with uncomplicated cystitis and conjunctivitis. In contrast, individual koalas with complicated cystitis were more likely to have anaemia, leukocytosis due to neutrophilia, hypoproteinaemia due to hypoalbuminaemia, and azotaemia due to elevated urea concentration. Although these changes were non-specific they did allow assessment of prognosis for survival and response to treatment. Koalas with lymphosarcoma were invariably anaemic, leukaemic, azotaemic and hypoalbuminaemic. Elevated enzymes (aspartate transaminase [AST]. lactate dehydrogenase [LD] and gamma glutamyl transferase [GGT]) were more common in koalas with lymphosarcoma. Koalas affected by miscellaneous conditions showed variable changes but once again anaemia, leukocytosis, azotaemia, elevated AST and LD, and hypoalbuminaemia were not uncommon. On the basis of these findings a minimal profile is suggested for the investigation of sick koalas and would include haematocrit, total and differential leukocyte counts, urea, total protein and albumin concentrations and AST, GGT and LD activities.     

Three<Emphasis Type="Italic">Orobanche</Emphasis> species newly found on crops in israel

Orobanche amethystea Thuill.,O. loricata Reichenb. andO. pubescens D’Urv. were found to parasitize the roots of cultivated plants in Israel.Orobanche pubescens is known from the local flora, and was now found to cause damage in parsley fields and toTropaeolum majus L. (nasturtium) in ornamental gardens.Orobanche amethystea andO. loricata are known as occasional weeds in Europe and were recently found for the first time in Israel.Orobanche amethystea densely populated vetch fields in Israel, andO. loricata was found in ornamental gardens. A key for the identification ofOrobanche species in cultivated areas in Israel is given, based on morphological features. http://www.phytoparasitica.org posting Jan. 13, 2002.     

Simulation study of the competitive ability of erect, semi-erect and prostrate cowpea (Vigna unguiculata) genotypes

Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterised, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus) and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM more accurately simulated actual field data for the competition of cowpea genotypes and sunflower than companion field experiments for the competition of cowpea and purslane. The validated simulation model of cowpea and sunflower at two densities was used to study the effects of cowpea growth habit on final biomass production of cowpea and sunflower. The model suggested that erect growth habit was more competitive than semi‐erect and prostrate growth habit, when cowpea genotypes were grown with sunflower. Cowpea leaf area distribution was important to higher cowpea biomass production, while cowpea height growth was important to reduce sunflower biomass. Our simulation approach is suggested as a method for crop breeders to gauge the likely success of selection for competitive crops before undertaking expensive long‐term breeding experiments.     

Testing of selected South African <Emphasis Type="Italic">Pinus</Emphasis> hybrids and families for tolerance to the pitch canker pathogen, <Emphasis Type="Italic">Fusarium circinatum</Emphasis>

Plantations of Pinus spp. constitute approximately 50% of the South African forestry industry. The first aim of this study was to develop a reliable inoculation technique to screen Pinus spp., for tolerance to infection by F. circinatum, which threatens pine forestry in South Africa. Inoculation of branches was compared with stem inoculations and we considered the number of branches or trees required to obtain statistically significant results. Furthermore, variation in the susceptibility of some Pinus families, clones and hybrids was considered. Results showed that branch inoculations were closely correlated with those from stem inoculations, and that it is important to consider branch and stem diameters when assessing susceptibility of trees. Subsequent trials using branch inoculations showed significant differences in F. circinatum tolerance amongst a range of pine species and hybrids of potential interest to forestry in South Africa. Significant differences in susceptibility were also found among clones of two P. radiata families. The most tolerant trees were P. elliottii × caribaea and P. patula × oocarpa hybrids, while the most susceptible species were P. patula, P. greggii and hybrids of these two. This is the first trial considering the susceptibility of Pinus hybrids, Pinus clones and some P. patula provenances, and the results indicate excellent potential for breeding for tolerance to pitch canker in South Africa. Application The accurate selection of disease tolerant planting stock for the South African forestry industry is crucially important for the continued sustainability of this important industry. The work described here provides valuable information on an artificial inoculation technique that will assist the industry in screening trees for tolerance to the pitch canker fungus, F. circinatum. It also provides some indication of the relative susceptibility of a number of Pinus spp., hybrids and families currently being evaluated in the country.     

Gonadotropin‐induced Puberty Does Not Impair Reproductive Performance of Gilts over Three Parities

The aim of this study was to evaluate the reproductive performance of three parities of gilts treated or not treated with gonadotropin to induce puberty. Sixty gilts received 600 IU of equine chorionic gonadotropin (eCG) followed by 2.5 mg of porcine luteinizing hormone (LH) 72 h later. Fifty‐nine other gilts were exposed only to a mature boar for 15 min twice daily. Artificial insemination (AI) was performed at 0, 12 and 24 h after the detection of oestrus, and gestation was confirmed by ultrasound after 35 days. Sows were inseminated at the first post‐weaning oestrus. The total numbers of piglets born, piglets born alive, stillborn, mummified foetuses, as well as pregnancy and farrowing rates were evaluated for each of the three parities. Culling rates, farrowing intervals and weaning‐to‐oestrous intervals (WEI) were also analysed. Mean age at puberty and oestrous manifestation were not significantly different between treatments (p = 0.0639; 179.20 ± 17.52 compared with 173.96 ± 16.94, 91.66% compared with 94.92%) across the experimental period. However, females that underwent puberty induction showed modest increases both in the number of total pigs born and in the number of piglets born alive. In conclusion, puberty induction through exogenous gonadotropin administration in field conditions did not induce a more concentrated first oestrous manifestation, but trended to a modest increase in the number of pigs born alive in the first parity and a reduced culling rate during the first gestation.     

Homogeneity of meats prepared for analysis with a commercial food processor: collaborative study

The food processor was evaluated as an alternative to the food chopper and bowl cutter for preparing meat samples for analysis in AOAC procedure 24.001. Samples of 6 meat types--cooked sausage, pork sausage, canned ham, hamburger, water-added ham, and smoked ham--were distributed to 9 laboratories for preparation using a food processor. The resulting 54 samples were sent to a USDA-accredited laboratory for analysis in triplicate for moisture, protein, and fat. Standard deviations and their 95% confidence intervals calculated for the analytical results were compared with USDA Performance Standards. With few exceptions, the upper limits were lower than the Performance Standards and for the exceptions, the intervals included the Performance Standards. By these criteria, the food processor is as effective in preparing homogeneous samples as the preparation procedures used to set the Performance Standards. Collaborators found the processor faster to use and easier to clean than the food chopper. Use of the food processor has received interim approval as an alternative to the food chopper or bowl cutter in AOAC procedure 24.001 for preparing meat samples for analysis.     

Crystal structure of defensin HNP-3, an amphiphilic dimer: mechanisms of membrane permeabilization

Defensins (molecular weight 3500 to 4000) act in the mammalian immune response by permeabilizing the plasma membranes of a broad spectrum of target organisms, including bacteria, fungi, and enveloped viruses. The high-resolution crystal structure of defensin HNP-3 (1.9 angstrom resolution, R factor 0.19) reveals a dimeric beta sheet that has an architecture very different from other lytic peptides. The dimeric assembly suggests mechanisms by which defensins might bind to and permeabilize the lipid bilayer.     

Muscle contraction and free energy transduction in biological systems

Muscle contraction occurs when the actin and myosin filaments in muscle are driven past each other by a cyclic interaction of adenosine triphosphate (ATP) and actin with cross-bridges that extend from myosin. Current biochemical studies suggest that, during each adenosine triphosphatase cycle, the myosin cross-bridge alternates between two main conformations, which differ markedly in their strength of binding to actin and in their overall structure. Binding of ATP to the cross-bridge induces the weak-binding conformation, whereas inorganic phosphate release returns the cross-bridge to the strong-binding conformation. This cross-bridge cycle is similar to the kinetic cycle that drives active transport and illustrates the general principles of free energy transduction by adenosine triphosphatase systems.