Using the natural abundance of nitrogen isotopes to identify cattle with greater efficiency in protein-limiting diets.

The difficulty in selecting cattle for higher feed and nitrogen use efficiency (NUE) is an important factor contributing to poor growth and reproductive performance in dry-tropics rangelands. Therefore, the objectives were to examine the cattle variation in retaining nitrogen in a protein-deficient diet and the natural abundance of stable isotopes in body tissues as a practical alternative for the detection of more efficient cattle. In experiment 1, feed efficiency parameters were determined in 89 Brahman steers fed a protein-limiting diet for 70 days, followed by 7 days in metabolism crates for total collection of urine and faeces and calculation of nitrogen retention and NUE. The diet-animal fractionation of nitrogen isotopes (Δ15N) was quantified in tail hair and plasma proteins using isotope-ratio MS. There was a large variation in growth performance, feed efficiency and nitrogen losses among steers. Quantifying Δ15N in tail hair (Δ15Ntail hair) resulted in stronger correlations with feed efficiency and nitrogen metabolism parameters than when quantified in plasma proteins. Δ15Ntail hair was positively correlated with nitrogen losses in urine (r = 0.31, P < 0.01) and faeces (r = 0.25, P = 0.04), leading to a negative correlation with NUE (r = -0.40, P < 0.01). The group of steers with lower Δ15Ntail hair had greater feed efficiency, lower nitrogen losses, and greater NUE. In experiment 2, for evaluation of isotope fraction as a predictor of reproductive performance, 630 Brahman-crossed cows were classified for reproductive performance for 2 years. From this group, 25 cows with poor reproductive performance and 25 cows with good reproductive performance were selected. Tail hair representing 7 months of growth were segmented and analysed for carbon (δ13C) and nitrogen (δ15N) isotope enrichment. Reproductive performance was not associated with diet selection, as there was no difference in tail hair δ13C between groups. However, more productive cows had lower (P < 0.05) tail hair δ15N during the dry season, indicating differences in N metabolism and possibly lower N losses. In addition, cows with better reproductive performance and, therefore, greater nutrient demands, had similar body condition scores and a tendency (P = 0.09) for higher live weight at the end of the trial. In conclusion, the findings of the present study confirm that nitrogen isotope fractionation in tail hair can be used as a predictor of nitrogen losses, NUE, and reproductive performance of Brahman cattle on low-protein diets.

Indigofera spicata (creeping indigo) poisoning of three ponies.

Three ponies continuously grazed a pasture containing an estimated 24% Indigofera spicata (wet weight basis) for 4-6 weeks in April and May 2004. They developed ataxia, paresis, depression, muscle fasciculations, dysphagia, ptyalism and halitosis. Two also developed corneal opacity. One pony recovered with supportive treatment, but the other two were euthanased and necropsied. Neuropathology was not present in either case, but both livers had periacinar and periportal lymphocytic infiltrations and hydropic degeneration of mid-zonal hepatocytes, with mild to moderate periacinar necrosis also evident in one. The I. spicata contained 2.66 mg 3-nitropropionic acid (3-NPA)/g dry matter and 1.5 mg indospicine/g dry matter. Indospicine, but not 3-NPA, was detected in serum from both of the euthanased ponies and indospicine was detected in heart, liver and muscle from the one pony in which this assay was performed. The clinical syndrome closely resembled 'Birdsville horse disease' caused by I. linnaei and was similar to that reported in horses poisoned by the closely related species I. hendecaphylla and to 3-NPA poisoning of other animals, including humans. 3-NPA is thought to cause this neurological syndrome. To our knowledge, this is the first authenticated report of I. spicata poisoning in grazing animals. We also report here the first published evidence that 3-NPA and indospicine exist in naturalised I. spicata in Australia and of the formation of indospicine residues in tissues of animals grazing paddocks infested with I. spicata.

Hepatotoxicosis in dogs consuming a diet of camel meat contaminated with indospicine.

BACKGROUND: Four dogs presented with clinical signs of severe hepatic disease after consuming a commercial camel meat diet. METHODS: Laboratory investigation revealed evidence of severe liver disease, including markedly increased serum alanine aminotransferase (ALT) activity and total bilirubin concentration, and prolonged clotting times. RESULTS: Two dogs deteriorated despite supportive therapy and were euthanased. Histologically, both livers appeared similar, with the main lesion being extensive periacinar necrosis and haemorrhage. Indospicine, a toxic amino acid of plant origin, was detected in the serum and/or plasma from all four dogs, as well as in tissues of a dog that was necropsied and in a sample of the camel meat fed to this animal. Serum biochemistry tests using blood samples collected from 15 additional dogs identified as having eaten the diet detected indospicine was in the serum of 14 and 3 had increased ALT activity. One of the latter dogs subsequently developed clinical signs of severe liver disease and was euthanased. CONCLUSION: To the authors' knowledge, this is the first published report of the detection of indospicine residues in camel meat and the occurrence of severe, sometimes fatal, liver disease in dogs that consumed this contaminated meat.

Carbon hydroxylation of alkyltetrahydropyranols: a paradigm for spiroacetal biosynthesis in Bactrocera sp.

[figure: see text] In a number of Bactrocera species the penultimate step in the biosynthesis of spiroacetals is shown to be the hydroxylation of an alkyltetrahydropyranol followed by cyclization. The monooxygenases that catalyze this side chain hydroxylation show a strong preference for oxidation four carbons from the hemiketal center, to produce the spiroacetal. The hydroxy spiroacetals observed in Bactrocera appear to derive from direct oxidation of the parent spiroacetals and not from alternate precursors.

Simvastatin-induced lupus-like syndrome.

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors are widely used as cholesterol lowering agents that have an acceptable safety profile. As a group, this class of drugs has been associated with few immunologic reactions. Simvastatin (Zocor) has been linked to three cases of drug-induced lupus-like syndrome. We report the case of an additional patient who developed pleurisy and arthralgia after he started taking this low-density lipoprotein and cholesterol-lowering agent.

Chemistry of fruit flies: Glandular secretion ofBactrocera (Polistomimetes) visenda (Hardy).

The major component (>90% of volatiles) of the male rectal glandular extract of the nonpest speciesBactrocera visenda (Hardy) is 3-methyl2-butenyl acetate, with minor components being the isomeric 3-methyl-3-butenyl acetate, the homologous esters, 3-methyl-2-butenyl propanoate and 3-methyl-2-butenyl formate, along with 3-methyl-2-buten-1-ol, 3-methyl-2-butenal, and 3-methylbutyl acetate. None of these compounds has been identified previously from aBactrocera species, supporting the view thatBactrocera visenda is taxonomically distant from otherBactrocera species identified from the Australian mainland. This collection of compounds adds to the known types utilized by dipteran species and emphasizes their extensive biosynthetic capability.

Chemistry of fruit flies: Nature of glandular secretion and volatile emission ofBactrocera (bactrocera) cacuminatus (Héring).

The major component of the rectal glandular extract and volatile emission of maleBactrocera cacuminatus is racemic 1,7-dioxaspiro[5.5]undecane. l-Hydroxy-5-nonanone as its open chain form, together with 6-n-butyl-3,4-dihydro-2H-pyran are minor components. 1,7-Dioxaspiro[5.5]undecan-4-ol is present at a low level and is shown to be exclusively the diastereomer with an equatorial hydroxy group by comparison with synthesized samples of both epimers. Examination of the trifiuoroacetate by chiral gas chromatography has established the (4S,6S) stereochemistry (ca. 80% ee). The presence of 1,7-dioxaspiro[5.5]undecan-3-ol, or its isomerization product, 1,6-dioxaspiro[4.5]decan-2-ylmethanol, could not be confirmed. Trapping of the volatiles released by sexually mature male flies at dusk revealed that a number of the glandular components described above are released at mating time. Reexamination of the glandular secretion of sexually mature female olive flies (B. oleae) has failed to confirm the presence of any 1,7-dioxaspiro[5.5]undecanols, with the only volatile component (other than fatty acids) being 1,7-dioxaspiro[5.5]undecane.

Chemical studies of rectal gland secretions of some species ofBactrocera dorsalis complex of fruit flies (diptera: Tephritidae).

Male-produced rectal gland secretions of a number of species now considered to be members of theBactrocera dorsalis complex of fruit flies have been examined by combined gas chromatography-mass spectrometry. The structures of a number of previously unreported compounds have been confirmed by synthesis and Chromatographic comparisons. Compounds identified in these secretions include fatty acids, esters, amides, keto alcohols, diols and spiroacetals. These chemical findings are in agreement with taxonomic revisions based on other criteria.

A note on the isoprenoid quinone content of Bordetella avium and related species.

The isoprenoid quinone content of isolates of Bordetella avium (four strains), Alcaligenes faecalis (one strain), Bordetella bronchiseptica (one strain) and a Bordetella avium-like organism (four strains) was determined by reverse-phase high-performance liquid chromatography. All the isolates contained ubiquinones with eight isoprene units as the major component. No menaquinones were detected.

Pulmonary function of the reserpine and isoproterenol models of cystic fibrosis.

Two experimental animal models exhibiting functional and morphologic changes of exocrine glands similar to those seen in patients with cystic fibrosis (CF) have been reported in the rat: chronic stimulation with reserpine (Martinez et al. 1973 Pediatr. Res. 9:463, 470) and chronic stimulation with isoprenaline (Sturgess and Reid 1973 Br. J. Exp. Pathol. 54:388). We have studied the pulmonary function of these models induced by injecting rats subcutaneously with reserpine (RES, 0.5 mg/kg/day), isoproterenol (ISO, 25 mg/kg/day), or saline (Con, 1.0 ml/kg/day) for 6 days. Plethysmographic measurements were made for functional residual capacity (FRC), airways resistance (Raw), specific airways conductance (sGaw), phase difference between air flow rate and mean alveolar pressure (PD), frequency of breathing (f), and tidal volume (VT) of the anesthetized rats. In the RES and ISO rats, the FRC, Raw and f were not different from Con values. The PD was greater and the VT was less than Con values (p less than 0.05). The results of both studies indicate uneven ventilation (increased PD) and penduluft (decreased VT) consistent with maldistribution of resistance and/or compliances of the peripheral airways and/or alveolar compartments. These physiologic effects can be related to the morphologic changes reported for the airways of rats under chronic adrenergic stimulation (ISO) and expected for rats under chronic catecholamines depletion (RES). Since peripheral airways involvement is usually the earliest pulmonary lesion found in CF, these studies indicate that the RES and ISO models may be representative of the early pulmonary involvement of CF.