The aim of this study was to determine which cells are the source of production and target for leukotriene (LTs) action within the bovine ovary. Luteal (CL, days 14–16 of the oestrous cycle), steroidogenic cells (LSC) and endothelial cells (LEC) of the bovine corpus luteum (CL), and granulosa cells (GC) were isolated enzymatically, cultured in a monolayer and incubated with LTC4, LTB4, Azelastine (an antagonist of LTC4) or Dapsone (an antagonist of LTB4). Then cells were collected for determination of mRNA expression for LT receptors (LTRs) and 5‐lipoxygenase (5‐LO) by real time RT‐PCR, and media were collected for determination of prostaglandin (PG)E2, F2α, progesterone (P4; LSC only), endothelin‐1 (ET‐1; LEC only) and 17‐β oestradiol (E2; GC only). The greatest mRNA expression for LTR‐II and 5‐LO were found in LEC, whereas LTR‐I mRNA expression did not differ among cell types. The level of PGE2 increased after LTs treatment in each type of ovarian cell, excluding LTC4 treatment in LEC. The secretion of PGF2α was also increased by LTs, but decreased after LTB4 treatment of LSC. In GC cultures, both LTs stimulated E2 secretion; in LEC cultures, LTB4 stimulated whereas LTC4 inhibited P4 secretion; in LEC cultures, LTC4 stimulated but LTB4 inhibited ET‐1 secretion. The results show that LTs are produced locally and are involved in PGs production/secretion in all examined cells (LSC, LEC and GC) of bovine ovary. Leukotriene treatment modulate secretion of E2, by GC, P4 by LSC and ET‐1 by LEC, which indicates that LTs are involved in regulation of ovarian secretory functions. 相似文献
Three white clover cultivars, S184 (small-leaved), Menna (medium-leaved) and Olwen (large-leaved), were sown at a seed rate of 3 kg ha-1 under spring wheat cv. Tonic. In the spring of the two following years, there were three pre-bud emergence mechanical defoliation treatments on which were superimposed four post-bud emergence treatments giving a total of twelve cutting treatments. Pre-bud emergence, plots were either cut twice (at approximately two weeks before bud emergence and at bud emergence), cut once at bud emergence or not cut. To each treatment were applied four post-bud emergence treatments: plots were not cut or cut once (one, two or three weeks after bud emergence). Counts of the total number of inflorescences and of the proportions in various ripeness categories were made throughout the period of seed crop development to determine the pattern of inflorescence development and optimum harvest date. Overall, inflorescence numbers were greatest in cv. S184and least in cv. Olwen. Defoliation before bud emergence had no effect on inflorescence production; however, it was significantly influenced by defoliation after bud emergence. Although delaying the initial development of the crop, inflorescence numbers of all cultivars were highest in both years following cuts two and three weeks after bud emergence. Optimum harvest date was not affected by defoliation or cultivar, numbers of ripe inflorescences in both years reaching a peak at the end of August. The number of brown inflorescences, which may also contribute to seed yield, reached a peak in both years in late July. Seasonal differences in inflorescence production were again observed, emphasizing the difference between first and second year crops and importance of climate in while clover seed production. The implications of these differences in numbers and proportions of inflorescences in various ripeness categories under different defoliation regimes are discussed in relation to seed crop management in the UK. 相似文献
The effects of different spring defoliation managements on potential harvestable seed yield and seed yield components of three contrasting white clover cultivars were assessed. The small-leaved cv. S184 produced more but smaller inflorescences than the large-leaved cv. Olwen and Menna, a medium-leaved cultivar. Cultivar Olwen, however, produced more ripe and brown (nearly ripe) inflorescences with more florets, seeds per floret and a higher seed yield per ten inflorescences than the other cultivars. Potential harvestable seed yield and individual seed yield components were only influenced by defoliation after bud emergence, as defoliation before bud emergence had no effect on seed yield components. Defoliation after bud emergence had a similar effect on all cultivars: the number of ripe inflorescences was unaffected by defoliation but the number of brown and therefore harvestable (ripe + brown) inflorescences was highest following defoliation three weeks after bud emergence. Florets per inflorescence, seed per floret, 1000 seed weight, seed yield per ten inflorescences and potential harvestable seed yield were not influenced by defoliation after bud emergence. Season had a significant effect on seed yield components and influenced the effect of defoliation treatments, emphasizing the importance of climate in white clover seed production. The results are discussed in relation to the spring defoliation of white clover seed crops, harvesting techniques and the provision of guidelines for optimizing seed yield. 相似文献
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
AIM: To describe the prevalence and spatial distribution of cattle herds infected with Ikeda and non-Ikeda types of Theileria orientalis in New Zealand between November 2012 and June 2013.
METHODS: Pooled serum samples collected historically between November 2012 and June 2013 were obtained from cattle herds throughout New Zealand. Each pooled sample consisted of approximately 20 individual cattle samples from that herd, and was provided with details of the spatial location of the herd (n=722). DNA from all samples was tested using two quantitative PCR assays for the detection of T. orientalis (all types) and the Ikeda type. The proportion of herds that were positive for T. orientalis and Ikeda type, or that were positive for T. orientalis but negative for Ikeda type (non-Ikeda positive) was determined for different regions of New Zealand.
RESULTS: The highest prevalence of herds infected with Ikeda type was detected in the Northland (33/35; 94%) and Auckland and the Waikato (63/191; 33%) regions. Only 2/204 (1%) herds were positive for the Ikeda type in the South Island. A high percentage of herds that were positive for non-Ikeda types was detected in the Gisborne and Hawkes Bay (23 (95%CI=13–37)%), Auckland and Waikato (22 (95%CI=16–29)%) and Bay of Plenty (24 (95%CI=10–44)%) regions.
CONCLUSIONS AND CLINICAL RELEVANCE: The high prevalence of Ikeda type detected in cattle herds in the Northland, Auckland and Waikato regions represents a risk to naive cattle being introduced into these regions. There is also the potential for resident cattle herds in the Gisborne and Hawkes Bay, Auckland, Waikato and Bay of Plenty regions to experience increased infection with the Ikeda type.
The overall impact experienced by regions will depend on other factors such as the number of herds present and the predominant type of farming, as well as the interplay between tick ecology, cattle immunity and movement patterns of cattle. 相似文献
AIMS: To use quantitative PCR assays to detect Theileria orientalis Ikeda type in cattle presumed infected with T. orientalis, to examine the relationship between theilerial piroplasm count and haematocrit (HCT), and the relationship with quantification cycle threshold (Cq) values.
METHODS: Blood samples in EDTA (n=1,024), derived from herds affected by anaemia associated with T. orientalis infection (TABA) between April and October 2013, were submitted for testing using quantitative PCR (qPCR) assays for T. orientalis and Ikeda type. Nucleotide sequencing of the major piroplasm surface protein (MPSP) gene was performed on 16 samples to identify T. orientalis types. Blood smear and/or HCT results were supplied with most samples. For data analysis, the number of theilerial piroplasm per 1,000 erythrocytes counted was categorised as negative (0), low (1–9), moderate (10–100) or high (>100). HCT was categorised as severely anaemic (<0.15 L/L), mildly anaemic (0.15–0.24 L/L) or not anaemic (>0.24 L/L). Differences between categories in proportion of samples positive for Ikeda type or mean Cq value were examined using χ2 tests or analysis of variance, respectively.
RESULTS: Of 1,022 samples containing amplifiable DNA, 916 (90%) were positive for T. orientalis and 789 (77%) were positive for Ikeda type. Nucleotide sequencing of MPSP amplicons also identified the presence of Chitose and Buffeli types in 11 samples without Ikeda. Ikeda was detected in a greater proportion of severely anaemic (288/302; 95%) than mildly anaemic (227/252; 90%) cattle (p=0.02). In non-anaemic cattle, 344/406 (85%) were positive for T. orientalis and 247/406 (60%) were positive for Ikeda type. In samples from cattle that were piroplasm-positive, a greater proportion of anaemic (483/505, 96%) than non-anaemic (211/307; 69%) cattle were positive for Ikeda type (p<0.001). In piroplasm-negative cattle, 20/37 (54%) anaemic and 25/78 (32%) non-anaemic cattle were Ikeda-positive (p<0.05). The distributions of Cq values differed between piroplasm count and HCT categories (p<0.001). Mean Cq differed between high and negative, and low piroplasm categories (p<0.001), but not between high and moderate categories (p=0.81), and differed between severely anaemic and mildly anaemic (p<0.001), and non-anaemic categories (p<0.001).
CONCLUSIONS: The Ikeda type was found in a high proportion of cattle during outbreaks of TABA in New Zealand. Analysis of Cq values suggested a relationship of Ikeda parasitaemia with severity of anaemia, but further investigation is required to better understand the role of parasitaemia in the pathogenesis of TABA. 相似文献
