Diet of powerful owls (Nixox strenua) living near Melbourne, Victoria

The diet of powerful owls (Ninox strenua) living at Christmas Hills, 35 km north-east of Melboume, was examined by analysis of 686 regurgitated pellets collected over two years. Mammalian prey was found in 89%, insects in 13%, vegetation in 11% and birds in 10% of the pellets. Of the mammals, common ringtail possums occurred most frequently in the pellets over the year. There was no seasonal difference in the frequency of occurrences of common ringtail possums and sugar gliders in pellets. However, common brushtail possums were more likely to be taken in spring than in the other seasons. More adult common ringtail possums were taken as prey than were other age classes over the year, except in summer when high numbers of young were consumed by the owls.

Molecular analysis of the protein-protein interaction between the E9 immunity protein and colicin E9

The specificity-determining region of the colicin E9 immunity protein (Im9) for its interaction with its cognate E colicin has been localized to residues 16-43 of the 86-amino-acid protein by the use of gene fusions. A comparison of the alignment of residues in this region of the Im2, Im8 and Im9 proteins have identified nine candidate specificity-determining residues. Using site-directed mutagenesis, we have changed each of these residues in the Im9 protein to the residue found in the same position in the Im8 protein. The immunity phenotype conferred by the mutant immunity protein was then tested. Of the nine residues, only one (Val34 to Asp) showed any evidence of conferring immunity to colicin E8. Changing other residues in the specificity-determining region to the equivalent Im8 residue did not affect the phenotype conferred by the mutant protein, with the exception of the change of Val37 to Glu, which resulted in low-level E8 immunity. While the substitutions at positions 34 and 37 of the Im9 protein introduced immunity towards ColE8, they did not diminish the immunity towards ColE9, suggesting that the two immunity proteins may have a common specificity framework which can be modified by single mutations. In addition, we have used chemical modification of the unique cysteine residue of Im9 (Cys23) in order to probe further this specificity-determining region. Cys23 in the purified Im9 protein is accessible to modification with the thiol-specific reagent 5,5'-dithiobis(2-nitrobenzoic acid) and the stoichiometry of labelling is close to 1:1. This residue, however, cannot be labelled by 5,5'-dithiobis(2-nitrobenzoic acid) when the Im9 protein is complexed to colicin E9. This result is consistent with the Cys23 residue being buried in the complex. However, when the purified Im9 protein modified at Cys23 with a variety of reagents was used in DNase inhibition assays with colicin E9, the modified Im9 proteins still possessed anti-DNase activity but only up to a certain derivative molecular mass. These results are discussed in terms of the proximity of Cys23 to the specificity-determining region.

Evaluation of a rapist as a function of expressed intent and remorse

Two studies were conducted to examine the effects of expressed versus denied intent and remorse on evaluation of a rapist. In both studies, the rapist was evaluated more negatively and was assigned a longer prison sentence when expressing rather than denying intent. The rapist received more favorable evaluations when expressing rather than denying remorse. Manipulation of the rapist's expressed remorse did not significantly affect the recommended prison sentence. However, the recommended prison sentence did correlate significantly with participants' perceptions of the rapist's remorse. A multiple regression analysis indicated that recommended prison sentence could be best predicted by attributions of cause, intent, and remorse. The results were related to a growing body of research on accounting strategies, responsibility, and excuse making.

In vivo and in vitro characterization of overproduced colicin E9 immunity protein

We report the overproduction of the immunity protein for the DNase colicin E9 and its characterization both in vivo and in vitro. The genes for colicin immunity proteins are normally co-expressed from Col plasmids with their corresponding colicins. In the context of the enzymatic colicins, the two proteins form a complex, thereby protecting the host bacterium from the antibiotic activity of the colicin. This complex is then released into the medium, whereupon the colicin alone translocates (through the appropriate receptor) into sensitive bacterial strains, resulting in bacterial cell death. The immunity protein for colicin E9 (Im9) has been overproduced in a bacterial host in the absence of its colicin, to enable sufficient material to be isolated for structural studies. As a prelude to such studies, the in-vivo and in-vitro properties of overproduced Im9 were analysed. Electrospray mass spectrometry verified the molecular mass of the purified protein and analytical ultracentrifugation indicated that the native protein approximates a symmetric monomer. Fluorescence-enhancement and gel-filtration experiments show that purified Im9 binds to colicin E9 in a 1:1 molar ratio and that this binding neutralizes the DNase activity of the colicin. These results lay the foundations for a full biophysical and structural characterization of the colicin E9 DNase inhibitor protein, Im9.

A national outbreak of salmonellosis from yeast flavoured products

A national outbreak of salmonellosis caused by a rare serotype occurred between July and November 1989. A total of 40 cases of Salmonella manchester infection were identified by the PHLS Division of Enteric Pathogens with a further 7 cases reported from Scotland. The median age of those affected was one year. All strains from the outbreak carried a 70mDal plasmid with a distinctive restriction endonuclease. A statistical association was found between infection and consumption of nationally distributed savoury corn snacks. Samples of autolysed yeast powder and flavourings used in the manufacture of many processed foods were also found to be positive for S. manchester.

Is a fat metabolite the major diet dependent accelerator of aging?

Previous work with a high fat/low carbohydrate diet indicated that Drosophila melanogaster aged faster on that diet than on a high carbohydrate/low fat diet. This could be due to one of eight possibilities enumerated. Oxygen consumption of flies on the high fat/low carbohydrate diet is initially the same as that on the control diet. Subsequently the oxygen consumption falls to below control levels at older ages. No increased rate of living is indicated. A starvation resistant strain is described. The male eats less food, and yet maintains a body fat level indistinguishable from the parent strain. The lifespan and most physiological indices of aging used indicate that the process of aging is unchanged. Nutrient dilution produces a nearly compensatory increase in food intake with a reduced body fat and body energy reserves. The indices of aging used indicate that the rate of aging is reduced under these circumstances. These results are consistent with the possibility that fat or a fat metabolite alters the rate of aging. It is argued from previous data that body fat itself is not likely to be the important factor, rather a metabolite is probably involved.

Inhibition of Human Platelet Function Induced by Sulphinpyrazone

A single 400 mg dose of sulphinpyrazone (S) administered orally to 5 volunteers inhibited arachidonic acid (AA)-induced platelet aggregation and platelet MDA production ex vivo biphasically. The initial inhibitory phase coincided with the maximum plasma concentration of S but the second phase occurred 24 h after dosing when no plasma S was detectable. At 2 h the concentration of AA inducing half-maximal aggregation was increased 1.95 times and at 24 h by 1.61 times. Dosing 7 volunteers with 200 mg q.d.s. for 7 days and 5 volunteers with 400 mg b.d.s. for 5 days also led to inhibitory activity against AA-induced platelet aggregation and MDA production which declined to zero 48 h after the last dose. Platelet count, fibrinogen, F VIII, β-TG and AT III were not influenced by the longer term treatment but bleeding time was slightly extended in all but one subject.

Biphasic Prolonged Inhibition of Platelet Prostaglandin Biosynthesis Induced by Sulphinpyrazone

In rabbits, high doses of sulphinpyrazone (S) result in prolonged inhibition of in vivo collagen-induced thrombocytopenia and platelet MDA production (Buchanan et al., Thromb. Res. 1978, 13., 883). After confirming these results we have shown in guinea pigs that 7 h after oral administration of S there was greater inhibition of AA-induced platelet aggregation than 1 h afterwards, i.e. at the peak plasma S concentration. Thus the concentration of AA needed to induce 50% maximal platelet aggregation at 7 h was raised 2.36 times and 4.73 times after 3 mg/kg and 10 mg/kg of S respectively. When in vivo thrombocytopenia was induced with the Arthus reaction the second phase of inhibition occurred down to a dose of 10 mg/kg p.o. with the first phase seen at higher doses. The inhibitory activity is associated with a high M.W. fraction of plasma proteins (50,000-100,000 Daltons). Phenylbutazone, aspirin andticlopidine did not induce the plasma-borne effect.

Pulmonary and systemic vascular responses of perinatal goats to prostaglandins E1 and E2

Effects of prostaglandins of the E series and their metabolites on pulmonary and systemic circulations of newborn and exteriorized fetal goats (anesthetized with chloralose) were evaluated in situ using an isolated perfused left lung lobe preparation. Prostaglandin E1 (PGE1) and, to a lesser extent, prostaglandin E2 (PGE2) infusions resulted in decreases of pulmonary vascular resistance (PVR) of fetal and neonatal goats. Infusions of PGE1 or PGE2 (less than 2 microgram.kg-1.min-1 for 1 min) directly into left pulmonary arterial blood did not affect systemic arterial pressure (SAP). Infusions of PGEs (greater than 2 microgram.kg-1.min-1 for 1 min) resulted in decreases in SAP and heart rate. The dose-response characteristics of the pulmonary circulation in response to PGE1 and PGE2 were not different in fetal and newborn goats. Fetal asphyxia did not alter the dose-response characteristics of pulmonary circulation in response to PGE1. Metabolites (15-keto) of PGE1 and PGE2 had no effect upon PVR or SAP of perinatal goats. These results demonstrate in perinatal mammals 1) vasodilator action of PGE1 and PGE2 on the pulmonary and systemic circulations, and 2) catabolism by the lungs of these prostaglandins.

The effects of indomethacin on the pulmonary vascular response to hypoxia in the premature and mature newborn goat

The effects of indomethacin on the pulmonary circulation and the response of the circulation to hypoxia were investigated in premature and mature newborns using an isolated perfusion technique on otherwise intact left lungs in situ. There was an increase in pulmonary vascular resistance and augmentation of the increase in pulmonary vascular resistance during hypoxia following indomethacin. These effects were greater in the premature than in the mature newborn. Indomethacin effectively removes a dilator influence on the pulmonary circulation. The results are consistent with the concept that prostaglandins are important in regulating pulmonary vascular resistance.

Effects of prostaglandins of the E-series on pulmonary and systemic circulations of newborn goats during normoxia and hypoxia

Effects of exogenous prostaglandins of the E-series on pulmonary and systemic circulations of newborn goats were investigated during normoxia and hypoxia. Pulmonary arterial infusion of prostaglandins E1 and E2 decreased pulmonary vascular resistance 20% and 14%, respectively, without systemic effects. Prostaglandin E1 abolished the pulmonary pressor response to hypoxia. Prostaglandin E2 was less effective in counteracting this hypoxic response. The increased pulmonary vascular resistance and augmented response to hypoxia following indomethacin administration was reversed by prostaglandin E1. Infusion of prostaglandin E1 directly into the pulmonary circulation may be of benefit to the distressed newborn with elevated pulmonary vascular resistance.

The effects of prostaglandin E on fetal pulmonary vascular resistance (38588)

The effects of PGE on pulmonary vascular resistance were investigated in fetal goats using an isolated perfusion technique on otherwise intact unventilated lobes. PGE decreased perfusion pressure in the left pulmonary artery under conditions of monary vascular resistance by vasodilatation of tonically contracted vascular smooth muscle. In our preparation, intrapulmonary PGE infusion did not alter femoral arterial pressure which suggests that PGE is inactivated in the fetal lung. Implications for PGE in the newborn with respiratory distress and increased pulmonary vascular resistance are discussed.