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71.
High susceptibility and low resistance allele frequency of Chrysodeixis includens (Lepidoptera: Noctuidae) field populations to Cry1Ac in Brazil 
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下载免费PDF全文 72.
Determining the bioavailability of contaminants and assessing the quality of sediments 总被引：1，自引：1，他引：0
Stephen AC Marklevitz Elizabete Almeida Joanna Flemming Jocelyne Hellou 《Journal of Soils and Sediments》2008,8(2):86-91
Background, Aims and Scope Our study determined the role of light, aeration, grain size, amount of sediments and of water, density of animals and presence
of additional food on the movement of Ilyanassa obsoleta. Spiked relative to reference sediments were also tested for avoidance or preference by the mud snails. Our goal was to develop
exposure conditions to be used in future assessment studies of the environmental quality of sediments inhabited by mud snails.
The behavioural response of the snails towards different concentrations of contaminated Halifax Harbour sediments placed in
one half of a tank relative to reference sediments in the other half is examined in Part 2 and a chemical link investigated.
Methods Animals were exposed in 7 L aquaria at 12°C to their native sediments placed in one or two halves of a tank and the effect
due to the presence of a light source, air bubbles, sediment grain size, added algae examined relative to the snails’ behaviour.
Preference or avoidance of one half of a tank relative to the second half, the immersed or dry glass surface represented the
various media to be chosen by snails. After choosing the optimum set up, exposures were performed in triplicate, under slightly
differing initial placement of the snails to compare means and variability in the results. Three specific biogenic chemicals,
cholesterol, coprostanol and a fatty acid methyl ester (FAME) were spiked at 0.002, 0.01, 0.05, 0.25 and 1.2 mg/g, dry weight
of sediment. A hexane, dichloromethane and methanol extract of harbour sediment were also spiked in reference sediments. In
all cases, the location of the snails was recorded over a period extending up to 96 hrs.
Results Twenty snails exposed during a 72 hrs period in commercial 7 L tanks containing 50 g of sediments (wet weight) in the bottom
half of a tank filled half way with seawater represented the chosen conditions to test the avoidance/preference behaviour
of snails for part of a tank. The presence of additional food on sediments attracted snails within 24 hrs of exposure.
Discussion A general lack of preference was indicated in exposures to three biologically derived compounds spiked in reference sediments,
i.e. a C-18 FAME, cholesterol and coprostanol. The repelling properties of a harbour sediment extract pointed to a role for
non polar chemicals.
Conclusions It is proposed that behaviour reflects a balance between the repelling effects of contaminants and the attractive value of
food. The present study provides a robust green assessment tool that is easy to set up to assess the quality of sediments.
Recommendations and Perspectives The interpretation of field observations regarding the abundance of animals during environmental assessments must consider
both nutritional and toxicological causes. Additional laboratory exposures are needed to determine which chemicals play a
role in the field. 相似文献
73.
Molecular characteristics of granulosa and cumulus cells and oocyte competence in Nelore cows with low and high numbers of antral follicles 下载免费PDF全文
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75.
Extract We wish to record the source of Figures 1a and 2 from the report “Porcine dermatitis and nephropathy syndrome in New Zealand” published in the New Zealand Veterinary Journal 56, 94–99, 2008. These images were kindly provided by AF Julian from Gribbles Veterinary, Hamilton, New Zealand, and illustrate the gross cutaneous and renal lesions that were typical of those seen in pigs in the reported disease outbreak. The images were obtained from a pig with porcine dermatitis and nephropathy syndrome submitted by one of the authors (DEBL) from a similar outbreak of the disease that was examined by Gribbles Veterinary, Hamilton. The failure to properly acknowledge this contribution is regretted. 相似文献
76.
Extract A lethal congenital polycystic kidney disease (PCKD) has been known in lambs in New Zealand for more than 50 years and assumed to be genetic in origin. We have studied this in lambs from an experimental mating in a flock experiencing an outbreak the previous year. Two Perendale rams identified by DNA profiling (SignaGen) as sires of PCKD lambs were each mated to the other's daughters. From 71 such matings, 10 ewes gave birth to 15 PCKD lambs of both sexes. The results are in accord with those expected for a recessive autosomal trait. All lambs were dead or died shortly after birth. Their abdomens were distended by enlarged kidneys 40–140 mm in length. Their cut surface showed a multitude of cystic spaces 1–5 mm in diameter in both the cortex and medulla. Livers of affected lambs showed complex tubular and cystic patterns of bile ducts containing bile, and supported by an excess of fibrous tissue. Cystic changes also occurred in the pancreas and salivary glands. 相似文献
77.
Abstract Extract A single case of the inherited lysosomal storage disease known as mucopolysaccharidosis-IIIA (MPS-IIIA), due to a deficiency of the enzyme heparan sulphatase, was reported in an 18-month-old male Huntaway dog (Jolly et al 2000). He had developed normally but when presented with a history of progressive ataxia over the preceding month, had a high stepping, prancing gait and difficulty in jumping into a utility vehicle. In addition, he had started to defaecate in his kennel. Following diagnosis of the enzyme deficiency, the mutant heparan sulphatase gene was sequenced and a PCR/restriction enzyme diagnostic test developed, based on the mutation. This is capable of detecting both homozygous and heterozygous individuals (Yogalingam et al 2000). 相似文献
78.
Effect of Follicle Size on In Vitro Maturation of Pre‐Pubertal Porcine Cumulus Oocyte Complexes 下载免费PDF全文
下载免费PDF全文 Very small follicles (<3.0 mm diameter) are over‐represented on the surface of ovaries of non‐cycling pigs, and the oocytes collected from these follicles generally have reduced developmental competence in vitro. This study examined the effect of follicle size on the nuclear maturation (n = 608), the potential of parthenogenetic activation (n = 243) and the cyclic AMP (cAMP) content of pre‐pubertal porcine oocytes (n = 480). In addition, the influence of follicle size on steroid hormone synthesis was analysed. Cumulus oocyte complexes (COCs) flushed from small (2.5–4.0 mm) or large (4.5–6.0 mm) ovarian follicles were cultured for 0, 28 and 46 h. After 46 h of IVM, a greater proportion of oocytes from 4.5‐ to 6.0‐mm follicles reach metaphase II (MII) compared with those from follicles with 2.5–4.0 mm of diameter (96.1 vs 77.0%, respectively; p < 0.001). Parthenogenetic activation of oocytes from large follicles produced higher developmental rates than oocytes from large follicles (p < 0.05). At 28 h, the IVM medium with oocytes from large follicles contained significantly more 17ß‐oestradiol (E2) than the medium with oocytes from small follicles (5.55 vs 3.45 ng/ml, respectively; p < 0.05) and at 46 h, the medium with oocytes from small follicles contained significantly more progesterone (P4) than the medium with oocytes from large follicles (276.7 vs 108.2 ng/ml, respectively, p < 0.05). Porcine oocytes from large follicles have higher nuclear and cytoplasmic maturation capacities, but the differences did not appear to be cAMP‐mediated. Our findings also suggest that COCs from small follicles undergo more intensive luteinization than COCs from large follicles. The results show that oocytes from follicles with a diameter greater than 4.0 mm are more suitable for in vitro studies. 相似文献
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80.
CEA Souza AA Araújo JTA Oliveira AC Lima Souza JNM Neiva AA Moura 《Reproduction in domestic animals》2010,45(4):644-653
We have investigated the reproductive development of the tropically adapted Santa Inês ram, the most common hair sheep in Brazil. From 8 to 48 weeks of age, 16 animals were evaluated for body and testis growth, semen parameters, testosterone concentrations and seminal plasma proteins, using two‐dimensional SDS‐PAGE. Animals were weaned at 30 days and kept in feedlots thereafter, receiving hay, concentrate (18% of crude protein) and mineral supplement. Body weight increased from 12.3 ± 0.7 to 54.3 ± 1.6 kg between 8 and 48 weeks (p < 0.05), but changes in thoracic perimeter and scrotal circumference were non‐significant after 36 weeks (p > 0.05). The percentage of motile sperm increased slowly until 23 weeks and more rapidly after that age, but significant changes in progressive motility occurred after 25 weeks. Presence of abnormal sperm related inversely to age. Most significant changes in sperm concentration occurred between 38 and 44 weeks (0.38 ± 0.05 to 1.14 ± 0.24 × 109 cells/ml, p < 0.05) and testosterone reached its highest concentrations at 42 weeks, decreasing afterwards. Rams reached puberty at 28.2 ± 0.8 weeks. The number of protein spots on seminal plasma gels was similar from 15 to 18 weeks (45 and 47 spots; p > 0.05), increased until 24 weeks (141 spots) and 28 weeks (170 spots; p < 0.05) and remained without significant (p > 0.05) changes from 28 to 48 weeks (186 ± 10 spots). Furthermore, the intensity of selected spots on 2D maps increased (p < 0.05) between 15 and 28 weeks, which preceded or coincided with the main developmental changes in sperm motility and percentage of defective sperm in the ejaculates. These results will support future studies designed to characterize specific seminal plasma proteins whose expression relate to the development of testis, epididymis and accessory sex glands. 相似文献