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61.
62.
Although many field trials have been conducted using Bacillus thuringiensis subsp. israelensis (Bti)-based formulations, most have been in rivers with different biotic and abiotic conditions thus rendering the evaluation of their performance very difficult. Recently, results of a threeyear experiment using a new field procedure brought new insight into the behavior and the performance (carry) of two liquid formulations of Bti, Teknar HP-D and Vectobac 1200L, tested in the same lotic environment and under similar abiotic and biotic conditions. Factors such as discharge, water temperature and the hyporheic zone were identified as elements affecting the downstream loss of activity of both products. However, to better understand the reduction of black fly mortality along a stream (measured by using gutters), data of residual dosages of both products (measured by laboratory assay with mosquito larvae) were compared with reduction of black fly mortality. Bti toxic activity was monitored from water samples taken at different distances downstream from an application point, and from probes driven into the hyporheic zone, to study the effects of abiotic factors on the loss of the toxic crystals. Results showed that the loss of dosage was exponential for both products but more crystals were recovered from Vectobac 1200L along the stream than from Teknar HP-D. However, the latter was more efficient, i.e. less toxins were needed to kill 50% of black fly larvae both in temperate (16°C) and warmer (19.5-22°C) water. Also, a rise in water temperature had a greater effect in the kill induced by Vectobac 1200L compared to Teknar HP-D. For the same residual dosages present at the stations, longer carries of toxin activity (higher mortalities) were obtained in warmer water. Finally, the hyporheic zone was identified as a major source of loss of activity of Bti products. Large stream discharges decreased the effect of the hyporheic zone and that was reflected in longer carry of the products. 相似文献
63.
MORBILLIVIRUS INFECTION IN BOTTLENOSE DOLPHINS: EVIDENCE FOR RECURRENT EPIZOOTICS IN THE WESTERN ATLANTIC AND GULF OF MEXICO 总被引:1,自引:0,他引:1
Pádraig J. Duignan Carol House Daniel K. Odell Randall S. Wells Larry J. Hansen Michael T. Walsh David J. St . Aubin Bert K. Rima Joseph R. Geraci 《Marine Mammal Science》1996,12(4):499-515
Morbillivirus infection is widespread among odontocetes of the western Atlantic and Gulf of Mexico. Serologic evidence of infection in bottlenose dolphins, Tursiops truncatus , was first detected during an epizootic along the mid-Atlantic coast in 1987. Here, we report recurrent epizootics in the coastal dolphin population since at least the early 1980s based on serological surveys and regional stranding frequencies. The first observed epizootic of this series occurred in the Indian and Banana Rivers in 1982 and was followed by others on the mid-Atlantic coast in 1987–1988 and in the Gulf of Mexico between 1992 and 1994. This temporal pattern of infection is likely facilitated by the population size and its fragmentation into relatively discrete coastal communities. Introduction of morbillivirus into a community with a sufficient number of naive hosts may precipitate an epizootic, depending on the potential for transmission within the group. Propagation of an epizootic along the coast is probably determined by frequency of contact between adjacent communities and seasonal migrations.
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities. 相似文献
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities. 相似文献
64.
Sebastian A Baldauf Harald Kullmann Stefanie H Schroth Timo Thünken Theo CM Bakker 《BMC evolutionary biology》2009,9(1):129-9
Background
Assortative mating patterns for mate quality traits like body size are often observed in nature. However, the underlying mechanisms that cause assortative mating patterns are less well known. Sexual selection is one important explanation for assortment, suggesting that i) one (usually the female) or both sexes could show preferences for mates of similar size or ii) mutual mate choice could resolve sexual conflict over quality traits into assortment. We tested these hypotheses experimentally in the socially monogamous cichlid fish Pelvicachromis taeniatus, in which mate choice is mutual. 相似文献65.
Identification of a trafficking motif involved in the stabilization and polarization of P2X receptors 总被引:7,自引:0,他引:7
Chaumont S Jiang LH Penna A North RA Rassendren F 《The Journal of biological chemistry》2004,279(28):29628-29638
Extracellular ATP-gated channels (P2X receptors) define the third major family of ionotropic receptors, and they are expressed widely in nerve cells, muscles, and endocrine and exocrine glands. P2X subunits have two membrane-spanning domains, and a receptor is thought to be formed by oligomerization of three subunits. We have identified a conserved motif in the cytoplasmic C termini of P2X subunits that is necessary for their surface expression; mutations in this motif result in a marked reduction of the receptors at the plasma membrane because of a rapid internalization. Transfer of the motif to a reporter protein (CD(4)) enhances the surface expression of the chimera, indicating that this motif is likely involved in the stabilization of P2X receptor at the cell surface. In neurons, mutated P2X(2) subunits showed reduced membrane expression and an altered axodendritic distribution. This motif is also present in intracellular regions of other membrane proteins, such as in the third intracellular loop of some G protein-coupled receptors, suggesting that it might be involve in their cellular stabilization and polarization. 相似文献
66.
Thierry Aubin Nicolas Mathevon Vincent Staszewski Thierry Boulinier 《Polar Biology》2007,30(8):1027-1033
Sex and individual recognition systems vary among species and can have various functions in different contexts. In order to determine the basis of identification by voice in the Kittiwake (Rissa tridactyla), the greeting calls of 32 individuals (18 males and 14 females) were recorded in May–June 2004 on the Kittiwake colony of Hornøya island (Barents sea) and analysed. On the basis of coefficient of variation calculations and discriminant analyses, we show (1) that calls are sexually dimorphic and that the dimorphism is mainly based on the value of the fundamental frequency, and (2) that calls are individually distinct, individuality being due to a complex of temporal and frequency parameters located in different parts of the signal. This coding strategy is discussed in the context of the colonial breeding habitat of the species. 相似文献
67.
Nicholas J Boddicker Angelica Bjorkquist Raymond RR Rowland Joan K Lunney James M Reecy Jack CM Dekkers 《遗传、选种与进化》2014,46(1):18
Background
Host genetics has been shown to play a role in porcine reproductive and respiratory syndrome (PRRS), which is the most economically important disease in the swine industry. A region on Sus scrofa chromosome (SSC) 4 has been previously reported to have a strong association with serum viremia and weight gain in pigs experimentally infected with the PRRS virus (PRRSV). The objective here was to identify haplotypes associated with the favorable phenotype, investigate additional genomic regions associated with host response to PRRSV, and to determine the predictive ability of genomic estimated breeding values (GEBV) based on the SSC4 region and based on the rest of the genome. Phenotypic data and 60 K SNP genotypes from eight trials of ~200 pigs from different commercial crosses were used to address these objectives.Results
Across the eight trials, heritability estimates were 0.44 and 0.29 for viral load (VL, area under the curve of log-transformed serum viremia from 0 to 21 days post infection) and weight gain to 42 days post infection (WG), respectively. Genomic regions associated with VL were identified on chromosomes 4, X, and 1. Genomic regions associated with WG were identified on chromosomes 4, 5, and 7. Apart from the SSC4 region, the regions associated with these two traits each explained less than 3% of the genetic variance. Due to the strong linkage disequilibrium in the SSC4 region, only 19 unique haplotypes were identified across all populations, of which four were associated with the favorable phenotype. Through cross-validation, accuracies of EBV based on the SSC4 region were high (0.55), while the rest of the genome had little predictive ability across populations (0.09).Conclusions
Traits associated with response to PRRSV infection in growing pigs are largely controlled by genomic regions with relatively small effects, with the exception of SSC4. Accuracies of EBV based on the SSC4 region were high compared to the rest of the genome. These results show that selection for the SSC4 region could potentially reduce the effects of PRRS in growing pigs, ultimately reducing the economic impact of this disease. 相似文献68.
cDNA fingerprinting of osteoprogenitor cells to isolate differentiation stage-specific genes. 总被引:2,自引:0,他引:2 下载免费PDF全文
A cDNA fingerprinting strategy was developed to identify genes based on their differential expression pattern during osteoblast development. Preliminary biological and molecular staging of cDNA pools prepared by global amplification PCR allowed discrim-inating choices to be made in selection of expressed sequence tags (ESTs) to be isolated. Sequencing of selected ESTs confirmed that both known and novel genes can be isolated from any developmental stage of interest, e.g. from primitive progenitors, intermediate precursors or mature osteoblasts. EST expression provides insight into possible interrelated physiological functions and putative interacting molecules during differentiation. This method offers a functional genomics approach to isolate differentiation stage-specific genes in samples as small as a single cell. 相似文献
69.
Background
Current methods for haplotype inference without pedigree information assume random mating populations. In animal and plant breeding, however, mating is often not random. A particular form of nonrandom mating occurs when parental individuals of opposite sex originate from distinct populations. In animal breeding this is called crossbreeding and hybridization in plant breeding. In these situations, association between marker and putative gene alleles might differ between the founding populations and origin of alleles should be accounted for in studies which estimate breeding values with marker data. The sequence of alleles from one parent constitutes one haplotype of an individual. Haplotypes thus reveal allele origin in data of crossbred individuals.Results
We introduce a new method for haplotype inference without pedigree that allows nonrandom mating and that can use genotype data of the parental populations and of a crossbred population. The aim of the method is to estimate line origin of alleles. The method has a Bayesian set up with a Dirichlet Process as prior for the haplotypes in the two parental populations. The basic idea is that only a subset of the complete set of possible haplotypes is present in the population.Conclusion
Line origin of approximately 95% of the alleles at heterozygous sites was assessed correctly in both simulated and real data. Comparing accuracy of haplotype frequencies inferred with the new algorithm to the accuracy of haplotype frequencies inferred with PHASE, an existing algorithm for haplotype inference, showed that the DP algorithm outperformed PHASE in situations of crossbreeding and that PHASE performed better in situations of random mating. 相似文献70.
Rupert CM Jones Maria Dickson-Spillmann Martin JC Mather Dawn Marks Bryanie S Shackell 《Respiratory research》2008,9(1):62