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1.
Liana Zanette 《Biological conservation》2002,103(3):323-329
Artificial nests are commonly used to evaluate predation, but the assumption that this method mimics predation on natural nests has seldom been tested. Natural and artificial nests of eastern yellow robins (Eopsaltria australis) were monitored in four, 55-ha plots over two breeding seasons. Overall, daily survival rates were higher (P<0.001) for natural (95%/day) than for artificial nests (88%/day). Among plots, daily survival rates for the two types of nests were not correlated with one another (P=0.72) indicating that the spatial pattern of predation on artificial nests did not mimic that for natural nests. Seasonal variation was evident for natural nests in one year, when they were more successful at the beginning and end of the breeding season. No seasonal patterns were observed for artificial nests in either year. Neither natural nor artificial nests showed annual variation in predation. Previous researchers concluded that large birds were important predators on robin nests. In this study, predation by large birds on artificial nests was positively correlated with the numbers of large birds counted on the plots (P=0.04). However, large birds depredated only 16% of artificial nests. Daily survival rates for artificial nests were recalculated using predation by large birds only. These rates were compared with natural nests, but there was still no correspondence in the spatial and temporal patterns of predation for the two types of nests. These results suggest that inferences about predation on natural nests based on artificial nest studies should be avoided. 相似文献
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Kottaridi C Nomikou K Teodori L Savini G Lelli R Markoulatos P Mangana O 《Veterinary microbiology》2006,116(4):310-316
Thirteen orf virus isolates obtained during the time period between 1995 and 2004 from crusted scab lesions of nine sheep and four goats from different geographical areas of Greece and Italy with suspected contagious ecthyma infection were analyzed. DNA of all isolates was successfully amplified by PCR with the primers 045F-045R and identified them as parapox virus. Partial DNA sequence of orf virus interferon resistant (VIR) gene, phylogenetic analysis of the available isolates and amino acid comparison of the interferon resistance protein encoded by this genomic region was carried out. According to the results of the present report a precise characterisation of the genomic region studied might provide evidence for the genetic variation and movement of the circulating orf virus strains. 相似文献
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Nogueira EO J Piantino Ferreira A Martins Soares R Luiz Durigon E Lazzarin S Brentano L 《Comparative immunology, microbiology and infectious diseases》2007,30(2):81-96
Specific amino acid (aa) substitutions in VP1, VP2 and VP3 genes were reported as a distinctive feature of the American CIA-1 strain, characterized as having a variable rate of growth and tropism for different MSB-1 cell sublines [Renshaw RW, Soiné C, Weinkle T, O'Connell PH, Ohashi K, Watson S, et al. A hypervariable region in VP1 of chicken anemia virus mediates rate of spread and cell tropism in tissue culture. J Virol 1996;70(12):8872-8]. DNA sequencing of 878 nucleotides from twelve Brazilian CAV, eight of which tested for in vitro isolation in three different sources of MDCC-MSB1 cell line and identified as lacking capacity to propagate in any of these cells, were compared to sequence data available for CAV strains propagated or not in cell culture. Alignment of the deduced aa resulted in a lack of singled out amino acid substitutions in the partial genomic sequences of Brazilian isolates that would entirely contrast them to viruses propagated in MSB-1 cells, indicating that the combined VP1, VP2 and VP3 substitutions observed may not entirely account as sole determinants of CAV isolation and propagation in MDCC-MSB-1 cells. 相似文献
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Nogueira-Dantas EO Ferreira AJ Astolfi-Ferreira CS Brentano L 《Comparative immunology, microbiology and infectious diseases》2007,30(3):133-142
Purification of chicken anemia virus (CAV) VP3 protein, expressed in a prokaryotic expression system as histidine-tagged fusion protein is demonstrated in the present study. CAV particle was obtained from infected liver of chicken and DNA was extracted. The VP3 protein gene was amplified from the extracted DNA by polymerase chain reaction (PCR) and cloned. The recombinant expression construct (pTrc-VP3) was identified by PCR and sequencing analysis. Expression of VP3 protein with a molecular mass of approximately 21kDa was confirmed by Western blotting analysis with CAV-specific antibodies. The in vitro expressed VP3 protein was purified to near homogeneity by elution from the gel, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The purified VP3 protein was recognized by CAV antibodies in a Western blotting assay. This finding indicates that recombinant VP3 expressed in the pTrcHis2 vector system can be used as antigen to detect anti-CAV antibodies. 相似文献
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Granum Espen Pérez-Bueno María Luisa Calderón Claudia E. Ramos Cayo de Vicente Antonio Cazorla Francisco M. Barón Matilde 《European journal of plant pathology / European Foundation for Plant Pathology》2015,142(3):625-632
European Journal of Plant Pathology - One of the most important soilborne diseases affecting avocado (Persea americana Mill.) crops is white root rot, caused by the fungus Rosellinia necatrix. In... 相似文献
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Madeleine C. Bottrill Jessica C. Walsh James E.M. Watson Liana N. Joseph Alejandro Ortega-Argueta Hugh P. Possingham 《Biological conservation》2011,(5):1595-1601
Recovery planning is a key component of government-funded initiatives to address declining populations of threatened species. To date, there has been limited retrospective evaluation on the impact of recovery plans, despite an increasing interest in evaluating recovery planning motivated by demands for greater accountability and a shift away from single-species focused strategies to multi-species, landscape and ecosystem-based plans. In the context of threatened species management in Australia, we aimed to investigate whether listed species with recovery plans are more likely to have improved their status compared to listed species without recovery plans. Since 1999, over 600 draft and approved recovery plans have been developed for more than 850 of 1663 species currently listed threatened species in Australia. We applied a novel econometric matching analysis to reduce biases associated with the non-random selection of species for listing and recovery planning. We found that the presence or absence of a recovery plan did not have a statistically significant effect on whether a species’ status was improving, stable or declining. The result suggests that recovery plans may not be useful in the short term and uncertainty persists about whether or not they make a long term contribution to species recovery. One major contributing factor is the lack of basic accounting of recovery planning efforts. This limits our ability to refute or confirm the impact of recovery planning on species status, and has the potential to reduce public confidence in government expenditures. Better systems for reporting and evaluation are therefore required to promote transparency, improve existing knowledge and facilitate efficient investments in future management actions. 相似文献
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Aklilu W Alemu Adam L Shreck Calvin W Booker Sean M McGinn Liana K D Pekrul Maik Kindermann Karen A Beauchemin 《Journal of animal science》2021,99(1)
The present study evaluated enteric CH4 production, dry matter (DM) intake (DMI), and rumen fermentation in feedlot cattle supplemented with increasing concentrations of 3-nitrooxypropanol (3-NOP). A total of 100 crossbred steers (body weight, 421 ± 11 kg) was randomly assigned to one of four treatments (n = 25/treatment): control (no 3-NOP) or low (100 mg/kg DM), medium (125 mg/kg DM), and high (150 mg/kg DM) doses of 3-NOP. The study was comprised of 28 d of adaptation followed by three 28-d periods, with CH4 measured for 7 d per period and cattle remaining on their respective diets throughout the 112-d study. Each treatment group was assigned to a pen, with the cattle and diets rotated among pens weekly to allow the animals to access the GreenFeed emission monitoring (GEM) system stationed in one of the pens for CH4 measurement. Measured concentration (mg/kg DM) of 3-NOP in the total diet consumed (basal diet + GEM pellet) was 85.6 for low, 107.6 for medium, and 124.5 for high doses of 3-NOP. There was a treatment × period interaction (P < 0.001) for DMI; compared with control, the DMI was less for the low and high doses in period 1, with no differences thereafter. Compared with control (10.78 g/kg DMI), CH4 yield (g/kg DMI) was decreased (P < 0.001) by 52%, 76%, and 63% for low, medium, and high doses of 3-NOP, respectively. A treatment × period effect (P = 0.048) for CH4 yield indicated that the low dose decreased in efficacy from 59% decrease in periods 1 and 2 to 37% decrease in period 3, while the efficacy of the medium and high doses remained consistent over time. Irrespective of dose, hydrogen emissions increased by 4.9-fold (P < 0.001), and acetate:propionate ratio in rumen fluid decreased (P = 0.045) with 3-NOP supplementation, confirming that other hydrogen-utilizing pathways become more important in the CH4-inhibited rumen. The study indicates that supplementation of corn-based finishing diets with 3-NOP using a medium dose is an effective CH4 mitigation strategy for commercial beef feedlots with a 76% decrease in CH4 yield. Further research is needed to determine the effects of 3-NOP dose on weight gain, feed conversion efficiency, and carcass characteristics of feedlot cattle at a commercial scale. 相似文献
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Sanchirico JN Stoffle R Broad K Talaue-McManus L 《Science (New York, N.Y.)》2003,301(5629):47-9; author reply 47-9
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Ian?G.?DroppoEmail author Liana?D’Andrea Bommanna?G.?Krishnappan Christina?Jaskot Brian?Trapp Mahendran?Basuvaraj Steven?N.?Liss 《Journal of Soils and Sediments》2015,15(2):467-479