To allow testing of microbial destruction in medical waste incinerators, methods were developed to determine indicator microorganisms (Bacillus Stearothermophilus spores) in incinerator air emissions and residue. The emission trapping train consisted of a water cooled glass probe and impingers containing a neutral phosphate buffer. In field tests, spores were injected directly into the probe, and results showed that approximately 60 percent of the spores were recovered. Spores were analyzed with adequate precision using a microbial membrane filter unit. Lab experiments indicated that spores were stable in neutral pH phosphate buffer for up to 20 days, and heat shocking samples (heating to 80-degrees-C for 20 minutes) reduced spore numbers in acidic or basic buffer. Laboratory tests also showed that 60 to 70 percent of spores initially added to ash were recovered up to 22 days after addition of the spores. In addition, lab tests showed that spores can be effectively recovered from residue test pipes spiked with indicator spores.
The toxicity of fifty sediment samples from a heavily industrialized urban embayment (Commencement Bay, Washington) and a non-urban inlet (Carr Inlet, Washington) was measured by three bioassay techniques: Microtox (bacterial luminescence), oyster embryo and amphipod tests. In comparison with Carr Inlet sediments, twenty-nine of the Commencement Bay sediments caused a significant (P< 0·05) decrease in bacterial luminescence, seventeen caused a significant (P<0·05) increase in amphipod mortality and sixteen caused significant (P< 0·05) increase in oyster embryo abnormality. Overa ll, nineteen (41%) of the Commencement Bay sediments were either toxic in all three bioassays or non-toxic in all three bioassays. Rank-order comparisons showed a high level of agreement among the three bioassays (Kendall's coefficient of concordance = 0·64, P < 0·001). However, individual correlations suggested considerable variation among the bioassays, which may be attributable to sensitivity to individual contaminants, differences in exposure routes and the heterogeneous distribution of contaminants in Commencement Bay sediments. These results indicate the usefulness of a diversity of toxicity testing procedures in wide-scale surveys of sediment contamination. Where a high degree of concordance exists among the various bioassays, a broadly based index may be developed that encompasses a wider range of sediment toxicity than would be evident from a single testing procedure.
Concanavalin A-agarose treatment of rat liver post-mitochondrial supernatant removes a fraction rich in cholesterol and 5'-nucleotidase activity but low in glucose-6-phosphatase. At the same time, radiolabel associated with the cell surface is removed. We interpret these findings as evidence that concanavalin A binds to, and under these circumstances will remove, fragments of plasma membrane present in the microsomal fraction and believe that this may be of use in the gentle, and rapid subfractionation of microsomal membranes.
Weaning weight (ww) and conformation score (cs) records from Angus calves in five New South Wales herds were analysed by least-squares procedures to assess the nature and magnitude of variation. Herd, year, age of dam and sex were considered as main effects. Covariates included in the models were weaning age (WA) for ww and average daily gain (ADG), and both WA and ww for cs. Male calves (steers and bulls) were 16.6 kg heavier at weaning than female calves. Dams that were 5-8 years of age weaned calves that were 30.1 kg, 15.4 kg and 6.7 kg heavier than 2-, 3- and 4-year-old dams respectively. When ww was not included as a covariate in the model, age of dam effects on cs reflected those on ww, and there was little difference in cs between males and females. When adjusted for differences in ww, males had poorer cs than females, and calves from 3-year-old dams, and from dams over 8 years old, had poorer cs than those from dams of all other ages. Partial regressions of ww and ADG on WA, and of cs on ww, varied considerably between herd/year/sex subgroups.