An Investigation of the Route and Progression of Encephalitozoon cuniculi Infection in Adult Rabbits

Rabbits infected either orally or intratracheally with cell culture-grown Encephalitozoon cuniculi were monitored regularly for serum antibody levels and E. cuniculi in the urine. Their responses were compared with intravenously inoculated and uninoculated control rabbits. All rabbits receiving E. cuniculi developed serum antibodies, generally within 3 weeks, and excreted E. cuniculi by 6 weeks. In the acute stage of infection, the organs most affected were lung, kidney and liver; the brain and gut were unaffected. However, during chronic infection, the brain, kidney, and heart were the only organs found to be involved. Antibody levels were very high at this stage. Thus both the oral and tracheal routes may be normal routes of infection with E. cuniculi in adult rabbits.     

Do feral honey bees (Apis mellifera) and regent parrots (Polytelis anthopeplus) compete for nest sites?

Abstract Surveys of nesting sites of feral honey bees (Apis mellifera) and regent parrots (Polytelis anthopeplus) were made in the red gum/black box woodlands of Wyperfeld National Park, Victoria, Australia. Data on tree species and size, and number of hollows were collected from all trees within seven 500 × 100m plots. Nest site characteristics were quantified for both bees and parrots. We found 27 feral honey bee colonies, suggesting a density of 77.1 colonies per km². The average occupation rate for bees was 1.3% of trees and 0.7% of available hollows. The height, aspect and entrance characteristics of honey bee nests at Wyperfeld were not qualitatively different to those reported elsewhere. We found 15 pairs of nesting regent parrots. Nest sites chosen by these birds overlapped those chosen by honey bees, but 52% of bee nests were in cavities unsuitable for regent parrots. We suggest that honey bee population growth may be limited in the park by a lack of water.     

Isolation and characterization of eight microsatellite loci in the mangrove mud‐nesting ant,Polyrhachis sokolova

We isolated and characterized eight anonymous microsatellite loci in the mangrove mud‐nesting ant, Polyrhachis sokolova. Three to 18 alleles were detected in 20 female workers collected from individual colonies at one location and observed heterozygosities ranged from 0.45 to 0.85. These microsatellite loci will be useful in studies on mating strategy, colony and population structure in P. sokolova.     

Invertase Activity and its Relation to Hexose Accumulation in Potato Tubers

Hexose accumulation was shown to occur in freshly harvestedmature potato tubers (Solanum tuberosum L.) both after storageat 10 ?C and when subsequently transferred to low temperature(3 ?C) storage. In general, changes in hexoses and sucrose werefound to be related to changes in acid invertase activity. Totalacid invertase activity (i.e. assayed after destroying the endogenousinvertase inhibitor present in the extracts) generally reflectedsugar changes more closely than did basal activity (i.e. assayedwith the inhibitor present). There was no evidence of a specificalkaline invertase. A comparison of the temperature responsesof cultivar Record with that of two SCRI² clones demonstrateddistinct genotypic variation in the extent of hexose accumulation.However, these differences were not always reflected by genotypicdifferences in total invertase activity. Key words: Invertase inhibitor, glucose, fructose, sucrose     

Elevated CO2 and moisture effects on soil carbon storage and cycling in temperate grasslands

In grassland ecosystems, most of the carbon (C) occurs below-ground. Understanding changes in soil fluxes induced by elevated atmospheric CO₂ is critical for balancing the global C budget and for managing grassland ecosystems sustainably. In this review, we use the results of short-term (1–2 years) studies of below-ground processes in grassland communities under elevated CO₂ to assess future prospects for longer-term increases in soil C storage.
Results are broadly consistent with those from other plant communities and include: increases in below-ground net primary productivity and an increase in soil C cycling rate, changes in soil faunal community, and generally no increase in soil C storage. Based on other experimental data, future C storage could be favoured in soils of moderate nutrient status, moderate-to-high clay content, and low (or moderateIy high) soil moisture status. Some support for these suggestions is provided by preliminary results from direct measurements of soil C concentrations near a New Zealand natural CO₂-venting spring, and by simulations of future changes in grassland soils under the combined effects of CO₂ fertilization and regional climate change.
Early detection of any increase in soil C storage appears unlikely in complex grassland communities because of (a) the difficulty of separating an elevated CO₂ effect from the effects of soil factors including moisture status, (b) the high spatial variability of soil C and (c) the effects of global warming. Several research imperatives are identified for reducing the uncertainties in the effects of elevated atmospheric CO₂ on soil C.     

Turf strength and root characteristics of ten turfgrass cultivars

Ten turfgrass cultivars were grown, singly and in mixtures, in glasshouse culture, to create standard sods. The tearing strength of the sods was measured using an Instron Universal Testing Instrument. Two Poa cultivars were found to be the strongest, followed in order of decreasing strength by three Festuca cultivars, three Lolium cultivars and two Agrostis cultivars. The relationship between the values obtained and shear strength of the sod root mass was investigated with a view to using this latter measurement as an indicator of tearing strength. No correlation between the two was found. Various characteristics of the root mass of individual plants were examined in an attempt to account for differences in turf strength: root system architecture (magnitude, altitude, pathlength and link numbers and lengths), root numbers at different soil depths and root mass. Sod tearing strength was found to be very strongly inversely related to the interior link length and mass of roots. The use of these as indices of strength is discussed.