Norsesquiterpene glycosides in bracken ferns (Pteridium esculentum and Pteridium aquilinum subsp. wightianum) from Eastern Australia: reassessed poisoning risk to animals     

Fletcher MT  Brock IJ  Reichmann KG  McKenzie RA  Blaney BJ 《Journal of agricultural and food chemistry》2011,59(9):5133-5138

Austral bracken Pteridium esculentum contains three unstable norsesquiterpene glycosides: ptaquiloside, ptesculentoside, and caudatoside, in variable proportions. The concentration of each of the glycosides was determined in this study as their respective degradation products, pterosin B, pterosin G and pterosin A, by HPLC-UV analysis. Samples of P. esculentum collected from six sites in eastern Australia contained up to 17 mg of total glycoside/g DW, with both ptaquiloside and ptesculentoside present as major components accompanied by smaller amounts of caudatoside. Ratios of ptaquiloside to ptesculentoside varied from 1:3 to 4:3, but in all Australian samples ptesculentoside was a significant component. This profile differed substantially from that of P. esculentum from New Zealand, which contained only small amounts of both ptesculentoside and caudatoside, with ptaquiloside as the dominant component. A similar profile with ptaquiloside as the dominant glycoside was obtained for Pteridium aquilinum subsp. wightianum (previously P. revolutum ) from northern Queensland and also P. aquilinum from European sources. Ptesculentoside has chemical reactivity similar to that of ptaquiloside and presumably biological activity similar to that of this potent carcinogen. The presence of this additional reactive glycoside in Australian P. esculentum implies greater toxicity for consuming animals than previously estimated from ptaquiloside content alone.  相似文献   

Solar radiation interception and canopy expansion of sweet corn in response to phosphorus   总被引：1，自引：1，他引：0  

Andrew L. Fletcher  Derrick J. Moot  Peter J. Stone 《European Journal of Agronomy》2008,29(2-3):80-87

Insufficient phosphorus (P) availability decreases the yield of Zea mays, particularly for sweet corn crops grown in cool environments. This research examined the mechanisms of yield reductions with initial emphasis on canopy expansion processes that affect the interception of solar radiation. Experiments in two consecutive seasons (2001/2002 and 2002/2003) were grown at a low P site (Olsen P = 6 μg ml⁻¹) at Lincoln, New Zealand. Each experiment contained five rates of P application. In 2001/2002 rates of 0, 50, 100, 150, or 200 kg P ha⁻¹ were applied. In 2002/2003 an additional 0, 0, 10, 20 or 40 kg P ha⁻¹ was applied to the same plots producing total P treatments of 0, 50, 110, 170 or 240 kg P ha⁻¹ summed over the two seasons.When P availability was limited (0 or 50 kg P ha⁻¹) the rates of leaf tip and fully expanded leaf appearance were slower in both seasons. Phyllochrons (°Cd leaf tip⁻¹) were 5 °Cd longer in crops that received 0 kg P ha⁻¹ than those fertilised with ≥100 kg P ha⁻¹. The area of individual leaves was also reduced by low P inputs but the ranking of leaf area by main stem leaf position was conservative. The leaf area of the largest leaf of the unfertilised crops was at least 22% less than the maximum measured leaf area in both seasons. In contrast, P fertiliser application had no effect on leaf senescence.The rate of leaf appearance per plant, individual leaf area and plant population were integrated to calculate green leaf area index (GLAI) and to estimate accumulated radiation interception (RI_cum) for these crops. The total RI_cum throughout the season in the unfertilised crops was 12–28% less than for those crops that received ≥100 kg P ha⁻¹ in both seasons. This difference partly explained the differences in crop biomass production in response to P availability. A sensitivity analysis showed that RI_cum was equally sensitive to changes of the rate of leaf appearance and the area of individual leaves in response to P supply. Both processes need to be incorporated in mechanistic models of P effects on Z. mays which can be used to design efficient P fertiliser strategies.  相似文献   

First report of Iris yellow spot virus on Allium cepa in New Zealand     

L. I. Ward  Z. Perez-Egusquiza  J. D. Fletcher  F. M. Ochoa Corona  J. Z. Tang  L. W. Liefting  E. J. Martin  B. D. Quinn  H. R. Pappu  G. R. G. Clover 《Plant pathology》2009,58(2):406-406

  相似文献   

Fibrosarcoma in a Père David's deer     

G B Hubbard  K C Fletcher  R E Schmidt 《Veterinary pathology》1983,20(6):779-781

  相似文献   

THE EMBLEMATIC USE OF THE TREE IN THE DAKOTAN GROUP     

Fletcher AC 《Science (New York, N.Y.)》1896,4(92):475-487

  相似文献   

Rings versus knife for docking and castration of lambs     

DJ MELLOR  RJ HOLMES † 《Australian veterinary journal》1988,65(12):403-404

  相似文献   

Fatal cardiomyopathy caused by Trypanosoma cruzi in an aardwolf     

K C Fletcher  G B Hubbard 《Journal of the American Veterinary Medical Association》1985,187(11):1263-1264

  相似文献   

A serological survey to determine the prevalence of infection with Treponema hyodysenteriae in Western Australia     

JRL MHOMA  DJ HAMPSON  ID ROBERTSON 《Australian veterinary journal》1992,69(4):81-84

A serological survey to detect antibody titres against Treponema hyodysenteriae was conducted on pigs from 106 herds in Western Australia. Titres indicating a positive result in the tests were determined by examining 400 sera from 4 herds known to be free of swine dysentery, and sera from immunised or experimentally infected pigs. Samples of serum from 40 bacon-weight pigs from each of the 106 herds were then collected at 2 abattoirs. Each serum was tested in enzyme-linked immunosorbent assays (ELISA) against the lipopolysaccharide of T hyodysenteriae of serogroups A, B and E, respectively. To assist in evaluating the test, 19 herds were resampled and retested, and faecal samples from 17 herds were cultured for T hyodysenteriae. Thirty-five of the 106 herds (33%) had serological evidence of infection when only one batch of sera from each herd was tested. The ELISA to detect T hyodysenteriae infection in herds using 40 sera was estimated as having a sensitivity of 77.3% and a specificity of 81.8% based on the owners' opinion of their herds disease status. Prevalence of infection within herds ranged from 2.5% to 47.5%, with a mean of 18%.  相似文献   

Chronic renal failure and urolithlasis in a 2-years-old colt     

EC SADLER  DJ WITT 《Australian veterinary journal》1992,69(10):262-262

  相似文献   

Reproduction in Javanese sheep: evidence for a gene with large effect on ovulation rate and litter size   总被引：2，自引：0，他引：2  

G E Bradford  J F Quirke  P Sitorus  I Inounu  B Tiesnamurti  F L Bell  I C Fletcher  D T Torell 《Journal of animal science》1986,63(2):418-431

Three breeds of Javanese sheep are described briefly and data suggesting the segregation of a gene with large effect on ovulation rate and litter size are presented. The three breeds are Javanese Thin Tail (JTT), Javanese Fat Tail (JFT) and Semarang (SEM), the last possibly a substrain of JTT. All three breeds have mean mature ewe weights under 30 kg. Ovulation rate and litter size did not differ significantly among the three; all had litter sizes of up to 4 or 5 with a mean for mature ewes of approximately 2. Ovulation rate ranged from 1 to 5 and had an average within-breed repeatability of .8 within season and .65 between seasons. Within-breed repeatability of litter size was .35 +/- .06. Prenatal survival in pregnant ewes with two, three and four or more ovulations averaged 93, 88 and 86% over two seasons. Dams that had at least one ovulation rate or litter size record greater than or equal to 3 produced two groups of daughters in approximately equal numbers: one group with many records greater than or equal to 3 and mean ovulation rate and litter size of 2.73 and 2.31, respectively, and one group with ovulation rates and litter sizes of 1 or 2 and corresponding means of 1.39 and 1.38. Dams with ovulation rate or litter size records of only 1 or 2 produced daughters in which over 90% had records of only 1 or 2. Estimated heritabilities for the mean of approximately three ovulation rate or litter size records from these daughter-dam comparisons exceeded .7. These results suggest segregation of a Booroola-type gene, one copy of which increases ovulation rate by about 1.3 and litter size by .9 to 1.0. Relationships between duration of estrus and ovulation rate, and between timing of release of luteinizing hormone and number of eggs shed, resemble the pattern in Booroola Merino more closely than that in Finnish Landrace or Romanov, supporting the hypothesis of a major gene.  相似文献