Species-specific DNA probes for Campylobacter species isolated from pigs with proliferative enteritis

Cloned, chromosomal DNA probes from porcine isolates of Campylobacter hyointestinalis and C. mucosalis were developed for the detection and identification of these putative swine enteric pathogens. High molecular weight chromosomal DNA from each species was used to construct genomic libraries in plasmids. Recombinants were selected which hybridized strongly to the homologous organism, but not to any other species of Campylobacter. Species-specific recombinants were labeled with phosphorus-32 and tested for sensitivity by dot blot hybridization to various dilutions of DNA and bacteria from each swine species, including C. hyointestinalis, C. mucosalis, C. coli and C. jejuni. Specificity was tested by hybridizing these probes against various strains of C. hyointestinalis or C. mucosalis, and against reference strains of all other described Campylobacter species. A C. hyointestinalis-specific probe and a C. mucosalis-specific probe were identified which were capable of detecting 1 ng of DNA or 10(4) cfu by bacterial spot blotting on nylon membranes. These probes hybridized to intestinal mucosal scrapings containing C. hyointestinalis and C. mucosalis obtained from pigs with proliferative enteritis, but not to material from normal pigs. Thus, cloned, chromosomal DNA probes may be useful in the detection and identification of bacteria involved in swine proliferative enteritis.     

家禽屠体的堆肥

加拿大安达略省家禽生产者对死禽处理通常有以下几种方法:选择经认证的死畜禽处理公司,坑埋,焚烧,堆肥.本文描述了使用堆肥法成功堆肥家禽屠体的一些关键因素. 堆肥是一个狭长的可被生物降解的有机物质堆,有很大的表面积以便氧气良好地渗透.堆肥通过需氧微生物分解生物有机物质制成一个稳定的、类似土壤的物质,称为腐殖质.为了刺激微生物快速降解,有必要给这些生长增殖的微生物提供最理想的环境.     

Lignin distribution across tracheid cell walls of poorly lignified wood from deformed copper deficient Pinus radiata (D. Don)

Summary Lignin topochemistry of tracheid walls from a deformed, copper deficient Pinus radiata (D. Don) tree was examined by linescan and point analyses using a Scanning Electron Microscope and Energy Dispersive Spectrometry. Both opposite and compression wood had abnormal lignin distributions compared to those observed in normal wood from a straight tree. Lignin contents in the compound middle lamella were lower than lignin contents in the secondary wall in both opposite and compression wood tracheids.One of us (G. D.) held a Commonwealth Forestry Postgraduate Research Award during this study. The research was supported in part by a grant from the Reserve Bank of Australia Rural Credits Development Fund, the Pine Fund, and members of the forest industry     

Characteristic site disturbance due to harvesting and extraction machinery traffic on sensitive forest sites with peat soils

The effects of wood harvesting and extraction machinery traffic on sensitive forest sites with peat soils were characterised with the objective of quantifying the threshold levels beyond which significant site impacts (compaction and rutting) would occur. The treatments involved running the machines in selected extraction racks (i.e., 3 m wide machine routes) while conducting normal wood thinning and extraction operations comprising one and two passes by the harvester and the forwarder with full payload, respectively. Soil disturbance thresholds were established by testing the level of significance of the difference in induced soil damage and compaction before and after machine traffic treatments. For volumetric soil water content lying between 10.0 and 14.9%, threshold cone penetration resistance levels for two 600/55–30.5 tyres were found to range from 594 to 640 kPa for deep-raised peat soil with initial strength lying between 524 and 581 kPa. In general, the proportion of the total rut depth data in each rack that exceeded the threshold level of 21.5 cm was about 5%. The threshold value corresponds to sinkage equivalent to 15% of the overall wheel diameter of the harvester, above which machine mobility would be hampered considerably. In addition, after harvester traffic the mean rut depth per unit rack length was 10.2×10⁻² cm/m, and it ranged from 0.7 to 24.7×10⁻² cm/m.