Effects of initial and extended exposure to an endophyte-infected tall fescue seed diet on faecal and urinary excretion of ergovaline and lysergic acid in mature geldings     

CL Schultz  SL Lodge-Ivey  LP Bush  AM Craig  JR Strickland 《New Zealand veterinary journal》2013,61(4):178-184

Abstract

AIM: To determine the amount of ergovaline and lysergic acid retained or excreted by geldings fed endophyte-infected seed containing known concentrations of these alkaloids, and the effects of exposure time on clinical expression of toxicosis.

METHODS: Mature geldings (n=10) received diets containing either endophyte-free (E-) or endophyte-infected (E+) tall fescue seed during three experimental phases. The first phase (Days ?14 to ?1) was an adaptation phase, to allow all horses to adapt to a diet containing E- tall fescue seed. The second (Days 0 to 3) was the initial exposure phase to E+ tall fescue seed, used for the delivery of ergovaline and lysergic acid at 0.5 and 0.3 mg/kg of diet, respectively, to test the initial effects of exposure on routes and amounts of elimination of alkaloid. During this phase, half the geldings were exposed to an E+ diet while the rest served as controls by remaining on the E- diet. Once assigned to treatments, geldings remained on the same diet through the third phase (Days 4 to 21), which served as the extended exposure phase. Total outputs of faeces and urine were collected within each phase, to determine retention of ergovaline and lysergic acid and nutrient digestibility. Serum was collected weekly and analysed for activities of enzymes and concentrations of prolactin. Bodyweights (BW) and rectal temperatures were recorded weekly.

RESULTS: BW, rectal temperature, enzyme activities and concentrations of prolactin in serum, and nutrient digestibility were not affected by treatment. Total intake of ergovaline by geldings on the E+ diet was 3.5 and 3.6 (SE 0.20) mg/day, and 2.1 and 2.3 (SE 0.11) mg/day were not accounted for in initial and extended phases, respectively. Lysergic acid was excreted in the urine (4.0 and 4.9 (SE 0.97) mg/day) and faeces (2.5 and 2.7 (SE 0.35) mg/day) at greater amounts than that consumed (2.0 and 1.9 (SE 0.09) mg/day) during the initial and extended exposure phases, respectively. Animals exposed to E+ seed for a period of 20 days appeared to excrete more (1.5 vs 1.2 mg/day; SE 0.08; p=0.03) ergovaline in the faeces than those exposed for only 4 days.

CONCLUSIONS: Exposure time to the ergot alkaloids had a limited effect on the route of elimination or the amounts of ergovaline or lysergic acid excreted by horses. The primary alkaloid excreted was lysergic acid, and urine was the major route of elimination. These data will aid future research to improve animals′ tolerance to toxic endophyte-infected tall fescue.  相似文献   

Copper deficiency in sheep: An assessment of the relationship between concentrations of copper in serum and plasma     

RA Laven  SL Smith 《New Zealand veterinary journal》2013,61(6):334-338

AIM: To assess the relationship between concentrations of copper in serum and plasma in sheep.

METHODS: Concentrations of Cu were measured in paired serum and heparinised plasma samples collected from 110 sheep in nine flocks. Linear regression was used to evaluate whether flock or gender had a significant effect on the association between concentrations of Cu in serum and plasma. The individual results for concentrations of Cu in serum were then compared with those from plasma, using correlation and limits of agreement plotting.

RESULTS: Concentrations of Cu in serum ranged from 7.3 to 22 (mean 14.0) µmol/L, while concentrations in plasma ranged from 9 to 27 (mean 16.3) µmol/L. On average, concentrations of Cu in serum were 2.3 µmol/L lower than in plasma. Over the range of values seen in this study, concentrations of Cu in plasma and serum were significantly correlated (r=0.89), and mean concentrations in serum were 87% of those in plasma. There was no effect of flock or gender on the relationship between concentrations of Cu in serum and plasma. Despite the significant correlation, there was marked variability between individual samples in the proportion of Cu that was lost during clotting, with the 95% limits of agreement for serum Cu ranging from 70 to 104% of the plasma concentration.

CONCLUSIONS: As in cattle, the individual variability in the loss of Cu during clotting in sheep is too great for concentration of Cu in serum to be used as a substitute for that in plasma.

CLINICAL RELEVANCE: When assessing the blood Cu pool as part of the diagnosis of Cu-responsive disease in sheep, the concentration of Cu in plasma should be measured in preference to that of serum. We suggest that a range of 4.5 to 9 µmol/L in plasma be used to define marginal Cu status in sheep.  相似文献   

Classic selective sweeps were rare in recent human evolution     

Hernandez RD  Kelley JL  Elyashiv E  Melton SC  Auton A  McVean G; Genomes Project  Sella G  Przeworski M 《Science (New York, N.Y.)》2011,331(6019):920-924

Efforts to identify the genetic basis of human adaptations from polymorphism data have sought footprints of "classic selective sweeps" (in which a beneficial mutation arises and rapidly fixes in the population).Yet it remains unknown whether this form of natural selection was common in our evolution. We examined the evidence for classic sweeps in resequencing data from 179 human genomes. As expected under a recurrent-sweep model, we found that diversity levels decrease near exons and conserved noncoding regions. In contrast to expectation, however, the trough in diversity around human-specific amino acid substitutions is no more pronounced than around synonymous substitutions. Moreover, relative to the genome background, amino acid and putative regulatory sites are not significantly enriched in alleles that are highly differentiated between populations. These findings indicate that classic sweeps were not a dominant mode of human adaptation over the past ~250,000 years.  相似文献   

"Stemness": transcriptional profiling of embryonic and adult stem cells   总被引：3，自引：0，他引：3  

Ramalho-Santos M  Yoon S  Matsuzaki Y  Mulligan RC  Melton DA 《Science (New York, N.Y.)》2002,298(5593):597-600

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Effect of density on brood size in noble crayfish,Astacus astacus L., subjected to indoor rearing conditions*     

T. TAUGB SL  J. SKURDAL 《Aquaculture Research》1990,21(1):17-23

Abstract. The effects of density, cover, and individual versus communal holding on brood size and female survival during the breeding period were examined in a large-scale experiment, involving 3591 mature noble crayfish, Astacus astacus L., females. Crayfish density during both mating/spawning and winter incubation had major effects on egg survival. In the high density experiment (67 and 44 individuals per m² during mating/spawning and winter incubation respectively) mean pleopod egg number in April was 18-20. Lowering the density to 50 during mating/spawning (still 44 individuals per m² during winter incubation) gave mean pleopod egg numbers of 31-38. In the low density experiment (50 and 33 individuals per m² during mating/spawning and winter incubation) mean pleopod egg numbers were 44-46. Egg-bearing females held in individual compartments with perforated bottom had a mean pleopod egg number of 25. Female survival during winter incubation was high, ranging from 91.8 to 98.3%. Covering the basins had no distinct effect on egg and female survival. In Astacus astacus culture we recommend that crayfish density should not exceed about 50 individuals per m² during mating/spawning and about 33 individuals per m² during winter incubation.  相似文献   

Mammary neoplasia in common brushtail possums: case report and retrospective identification of additional cases     

L Setyo  SL Donahoe  K Rose  D Spielman 《Australian veterinary journal》2020,98(6):243-246

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Imaging and microanalyses of mercury in flood plain soils of east fork poplar creek     

L. A. Harris  T. J. Henson  D. Combs  R. E. Melton  R. R. Steele  G. C. Marsh 《Water, air, and soil pollution》1996,86(1-4):51-69

Electron probe microanalysis, scanning electron microscopy with energy dispersive spectrometry, optical microscopy, and x-ray diffractometry were used to locate, identify, and analyze Hg-bearing matter in the soils from the East Fork Poplar Creek floodplain located adjacent to D.O.E.'s Oak Ridge Y-12 Plant Managed by Martin Marietta Energy Systems, Inc., for the U.S. Department of Energy under contract DE-AC05-84OR21400. Oak Ridge, Tennessee. Several significant findings were made in this study; namely, that ash concentration in soils is an indicator of Hg enrichment, the modes of occurrence of Hg are identical in so-called Hg-rich and Hg-poor soils, and Hg was found to coexist with S in all cases. In addition to Hg other materials employed at the Oak Ridge site such as U, Th, alloys, and rare earth were also observed.  相似文献   

LINEAR AND DENDRITIC SINK-HOLE PATTERNS IN SOUTHEASTERN NEW MEXICO     

Melton FA 《Science (New York, N.Y.)》1934,80(2066):123-124

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Natural infection of wild doves (Streptopelia senegalensis) with the virus of psittacine beak and feather disease     

DA PASS  SL PLANT  N. SEXTON 《Australian veterinary journal》1994,71(9):307-308

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Variation of interplate fault zone properties with depth in the japan subduction zone   总被引：2，自引：0，他引：2  

SL Bilek  T Lay 《Science (New York, N.Y.)》1998,281(5380):1175-1178

The depth dependence of physical properties along the Japan subduction zone interface was explored using teleseismic recordings of earthquake signals. Broadband body waves were inverted to determine the duration of rupture and source depth for 40 interplate thrust earthquakes located offshore of Honshu between 1989 and 1995. After scaling for differences in seismic moment, there is a systematic decrease in rupture duration with increasing depth along the subducting plate interface. This indicates increases in rupture velocity or stress drop with depth, likely related to variation in rigidity of sediments on the megathrust.  相似文献