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Forty-seven isolates of Sclerotinia species, collected from a variety of crops growing in Australia, New Zealand, North America and Europe, have been classified into three distinct groups on the electrophoretic patterns for soluble proteins, arylesterase, acid phosphatase, tetrazolium oxidase, glucose-6-phosphate dehydrogenase (NADP-linked) and reduced nicotinamide adenine dinucleotide phosphate dehydrogenase. There were only small intra-group differences. The electrophoretic patterns of an isolate of Whetzelinia (= Sclerotinia) tuberosa were characteristically different from those of the other isolates. These results support the findings from previous studies when ontogenetic, electrophoretic and mycelial-interaction criteria were used to group a smaller number of isolates from New South Wales, Australia. It is concluded that S. sclerotiorum, S. trifoliorum and S. minor are three distinct species.  相似文献   

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Loud and frequent vocalizations play an important role in courtship behavior in Cervus species. European red deer (Cervus elaphus) produce low‐pitched calls, whereas North American elk (Cervus canadensis) produce high‐pitched calls, which is remarkable for one of the biggest land mammals. Both species engage their vocal organs in elaborate maneuvers but the precise mechanism is unknown. Vocal organs were compared by macroscopic and microscopic dissection. The larynx is sexually dimorphic in red deer but not in elk. The laryngeal lumen is more constricted in elk, and narrows further during ontogeny. Several elements of the hyoid skeleton and two of four vocal tract segments are longer in red deer than in elk allowing greater vocal tract expansion and elongation. We conclude that elk submit the larynx and vocal tract to much higher tension than red deer, whereby, enormously stressed vocal folds of reduced effective length create a high resistance glottal source. The narrow, high impedance laryngeal vestibulum matches glottal and vocal tract impedance allowing maximum power transfer. In red deer longer and relaxed vocal folds create a less resistant glottal source and a wider vestibulum matches the low glottal impedance to the vocal tract, thereby also ensuring maximum power transfer. J. Morphol., 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

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The aim of this work was to compare the effect of reversible post-translational modifications, S-nitrosylation and S-glutathionylation, on the properties of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and to reveal the mechanism of the relationship between these modifications. Comparison of S-nitrosylated and S-glutathionylated GAPDH showed that both modifications inactivate the enzyme and change its spatial structure, decreasing the thermal stability of the protein and increasing its sensitivity to trypsin cleavage. Both modifications are reversible in the presence of dithiothreitol, however, in the presence of reduced glutathione and glutaredoxin 1, the reactivation of S-glutathionylated GAPDH is much slower (10% in 2 h) compared to S-nitrosylated GAPDH (60% in 10 min). This suggests that S-glutathionylation is a much less reversible modification compared to S-nitrosylation.Incubation of HEK 293 T cells in the presence of H2O2 or with the NO donor diethylamine NONOate results in accumulation of sulfenated GAPDH (by data of Western blotting) and S-glutathionylated GAPDH (by data of immunoprecipitation with anti-GSH antibodies). Besides GAPDH, a protein of 45 kDa was found to be sulfenated and S-glutathionylated in the cells treated with H2O2 or NO. This protein was identified as beta-actin. The results of this study confirm the previously proposed hypothesis based on in vitro investigations, according to which S-nitrosylation of the catalytic cysteine residue (Cys152) of GAPDH with subsequent formation of cysteine sulfenic acid at Cys152 may promote its S-glutathionylation in the presence of cellular GSH. Presumably, the mechanism may be valid in the case of beta-actin.  相似文献   

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The authors analyzed data collected over 26 years from 143 cryptorchid bulls admitted to 23 North American veterinary schools. Breed was found to be a risk factor. The medical records of 41 cryptorchid cattle were also obtained, and the physical examination findings, method of diagnosis, and surgical management were recorded. Polled Hereford and Shorthorn cattle were at significantly greater risk for cryptorchidism; however, polled cattle were not at an increased risk for cryptorchidism. Cryptorchidism was most commonly diagnosed by external palpation of the superficial inguinal rings and by palpation per rectum. Unilateral cryptorchidism appears to be more common than bilateral cryptorchidism. The incidence of cryptorchidism was 69% for the left testis and 31% for the right testis. Sixty-six percent of the retained testes were located in the inguinal canal. Cryptorchidectomy was performed through an inguinal, paramedian or flank approach in 26 bulls. Cryptorchidism appears to be rare in bovine bulls admitted to North American veterinary schools, with 1.7 cases per 1,000 bull admissions. We suggest that cryptorchidism be considered an inherited trait in the Shorthorn and Polled Hereford breeds.  相似文献   

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Molt is critical for birds as it replaces damaged feathers and worn plumage, enhancing flight performance, thermoregulation, and communication. In passerines, molt generally occurs on the breeding grounds during the postbreeding period once a year. However, some species of migrant passerines that breed in the Nearctic and Western Palearctic regions have evolved different molting strategies that involve molting on the overwintering grounds. Some species forego molt on the breeding grounds and instead complete their prebasic molt on the overwintering grounds. Other species molt some or all feathers a second time (prealternate molt) during the overwintering period. Using phylogenetic analyses, we explored the potential drivers of the evolution of winter molts in Nearctic and Western Palearctic breeding passerines. Our results indicate an association between longer photoperiods and the presence of prebasic and prealternate molts on the overwintering grounds for both Nearctic and Western Palearctic species. We also found a relationship between prealternate molt and generalist and water habitats for Western Palearctic species. Finally, the complete prealternate molt in Western Palearctic passerines was linked to longer days on the overwintering grounds and longer migration distance. Longer days may favor the evolution of winter prebasic molt by increasing the time window when birds can absorb essential nutrients for molt. Alternatively, for birds undertaking a prealternate molt at the end of the overwintering period, longer days may increase exposure to feather‐degrading ultra‐violet radiation, necessitating the replacement of feathers. Our study underlines the importance of the overwintering grounds in the critical process of molt for many passerines that breed in the Nearctic and Western Palearctic regions.  相似文献   

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ABSTRACT: BACKGROUND: Geographical isolation has generated a distinct difference between Atlantic salmon of European and North American Atlantic origin. The European Atlantic salmon generally has 29 pairs of chromosomes and 74 chromosome arms whereas it has been reported that the North American Atlantic salmon has 27 chromosome pairs and an NF of 72. In order to predict the major chromosomal rearrangements causing these differences, we constructed a dense linkage map for Atlantic salmon of North American origin and compared it with the well-developed map for European Atlantic salmon. RESULTS: The presented male and female genetic maps for the North American subspecies of Atlantic salmon, contains 3,662 SNPs located on 27 linkage groups. The total lengths of the female and male linkage maps were 2,153 cM and 968 cM respectively, with males characteristically showing recombination only at the telomeres. We compared these maps with recently published SNP maps from European Atlantic salmon, and predicted three chromosomal reorganization events that we then tested using fluorescence in situ hybridization (FISH) analysis. The proposed rearrangements, which define the differences in the karyotypes of the North American Atlantic salmon relative to the European Atlantic salmon, include the translocation of the p arm of ssa01 to ssa23 and polymorphic fusions: ssa26 with ssa28, and ssa08 with ssa29. CONCLUSIONS: This study identified major chromosomal differences between European and North American Atlantic salmon. However, while gross structural differences were significant, the order of genetic markers at the fine-resolution scale was remarkably conserved. This is a good indication that information from the International Cooperation to Sequence the Atlantic salmon Genome, which is sequencing a European Atlantic salmon, can be transferred to Atlantic salmon from North America.  相似文献   

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A population comprising 102 doubled haploid lines were produced from a cross between Beka, a barley cultivar widely grown in Spain, and Logan, a north American cultivar with inherently low protein content, a character considered to derive from the cultivar Karl. The intentions were to determine whether low-nitrogen malting barleys could be developed in Spain, and if genetic factors that influenced protein content were similarly expressed in widely diverse environments, i.e. northeastern Spain and eastern Scotland. An extensive map comprising 187 molecular markers was developed. Expressed sequence-tagged-derived markers were used in addition to anonymous simple sequence repeats to determine the potential for identifying candidate genes for quantitative trait loci (QTLs), and 22 such markers were mapped for the first time. There was transgressive segregation for both yield and protein content, and the gene for low protein from Logan was not expressed in the Scottish environment. In 2002, high yield was associated with earlier heading date in Spain, while late heading at the Scottish site was associated with greater lodging and lower thousand-kernel weight. These appeared to be possible pleiotropic effects of a factor detected on chromosome 2H. Using information from a consensus map, it was shown that this locus on 2H was in the region of the photoperiod response gene Eam6. A QTL explaining 18% of the variation in grain protein content was detected on chromosome 5H in a region in which a gene for nitrate reductase was previously observed. No effect on grain protein was associated with chromosome 6H, which has been suggested as the location of the low protein gene from Karl. However, it is likely that Karl contained more than one genetic factor reducing protein, and we postulate that the gene on 6H may have been lost during the breeding of Logan.  相似文献   

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Green and European Atlantic sturgeon are listed as a vulnerable and a critically endangered species, respectively. These anadromous species inhabit different continents but have many similar life history traits and demographic characteristics, including wide geographic ranges, similar migratory and foraging behavior, age and size structures of reproductive stocks and, historically, diverse population structures. The differences are limited to tetraploid genome and much larger egg size and lower fecundity in green sturgeon, reflecting the adaptations to different geomorphology and biota of the Pacific region. Both species have been affected by over-harvest and habitat losses but the severity of these impacts have been greater and lasted longer for the European Atlantic sturgeon, resulting in loss of diversity and extirpation of all but one stock. From the comparison of human impact on two species we conclude that preventive actions should be taken at the early warning signs of changes in population and recruitment. These should mitigate multiple factors of human activity affecting sturgeon stocks and their habitats.  相似文献   

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The technique of isoenzyme (enzyme isotype) electrophoresis was used to compare genetic profiles of extracts of zoites of sarcocysts from North America and Australasia. The species examined were Sarcocystis muris (Railliet, 1886) from mice, S. gigantea (Railliet, 1886) (syn. S. ovifelis Heydorn et al., 1975) from sheep, S. capracanis Fischer, 1979 from goats and S. cruzi (Hasselmann, 1923) (syn. S. bovicanis Heydorn et al., 1975) from cattle. Sarcocysts from the four host animals had different alleles at almost all loci studied. This was not affected by having a common definitive host. Extracts of two cat-borne Sarcocystis species shared alleles at only 3 out of 16 loci, while two dog-borne Sarcocystis species had different alleles at 8 out of 16 loci. The extent of genetic divergence among sarcocysts confirmed the existance of distinct species in each host sampled. By contrast, the isolates from the United States of America and Australasia for any particular host were essentially identical, sharing at least one allele at every locus tested. ac]19860908  相似文献   

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On 5 December 2013 the European Council promulgated Directive 2013/59/EURATOM. This Directive is important for Medical Physicists and Medical Physics Experts as it puts the profession on solid foundations and describes it more comprehensively. Much commentary regarding the role and competences has been developed in the context of the European Commission project “European Guidelines on the Medical Physics Expert” published as Radiation Protection Report RP174. The guidelines elaborate on the role and responsibilities under 2013/59/EURATOM in terms of a mission statement and competence profile in the specialty areas of Medical Physics relating to medical radiological services, namely Diagnostic and Interventional Radiology, Radiation Oncology and Nuclear Medicine. The present policy statement summarises the provisions of Directive 2013/59/EURATOM regarding the role and competences, reiterates the results of the European Guidelines on the Medical Physics Expert document relating to role and competences of the profession and provides additional commentary regarding further issues arising following the publication of the RP174 guidelines.  相似文献   

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PurposeThough the number of women scientists is increasing over the years, studies show that they are still under-represented in leadership roles. The purpose of this work is to establish the percentage of women Medical Physicists (wMPs) that have participated in European scientific events and evaluate it as an indication of the current position of women in the field of Medical Physics in Europe and to propose possible ways to encourage their participation.Materials and MethodsData regarding the participants in European scientific events of Medical Physics were collected. The participants were divided into categories according to the program of the events and their gender was identified. The percentage of wMPs in each category was evaluated.ResultsThe participation of wMPs attending courses is greater than 50%. The categories with the greatest participation are “Organizing Committees”, “Chairpersons-Moderators” and “Oral Presentations”. The categories with the lower participation of wMPs are “Scientific Committee”, “Symposiums” and “Invited Speakers”. None of wMPs were represented as “Course Directors”.ConclusionsThe attendance of wMPs in courses is slightly greater than average. However, wMPs do not have an equally important recognition in special invited roles in conferences. They are still under-represented in “Scientific Committees”, “Invited Speakers”, “Symposiums” and “Course directors”. wMPs should be encouraged to participate even more actively in European conferences and the organizing committees should invite more wMPs in special roles. More studies concerning the status of female MPs in each country separately should be encouraged as they will help in understanding the position of wMPS in Europe.  相似文献   

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Hemoglobin G Taegu, an electrophoretically slow hemoglobin variant found in four among 6700 apparently normal Korean subjects, has been shown to have a structural anomaly at position 22 of the beta-chain where an alanyl residue occurs in place of the glutamyl group normally found at that position in Hemoglobin A. The same structural anomaly initially was established by other workers in slow hemoglobin variants occurring in North American Indians and more recently has been reported in a Northern Chinese subject. The identical hemoglobins in the three ethnic groups are Hemoglobins G Coushatta, found in several Alabama-Coushatta Indians in Tex.; G Saskatoon, seen in a few descendants of Santee Indians currently living in Canada; G Hsin-Chu, in a Chinese from the northern province of Liaoning and currently living in Taiwan; and G Taegu in Koreans. It is assumed that the Chinese and Korean subjects have the same hemoglobin variant because of gene flow. No similar assumption connecting these two groups with the North American Indian subjects is considered warranted with the presently limited available information.  相似文献   

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The paradox of successful invading species is that they are likely to be genetically depauperate compared to their source population. This study on Colorado potato beetles is one of the few studies of the genetic consequences of continent-scale invasion in an insect pest. Understanding gene flow, population structure and the potential for rapid evolution in native and invasive populations offers insights both into the dynamics of small populations that become successful invaders and for their management as pests. We used this approach to investigate the invasion of the Colorado potato beetle (Leptinotarsa decemlineata) from North America to Europe. The beetles invaded Europe at the beginning of the 20th century and expanded almost throughout the continent in about 30 years. From the analysis of mitochondrial DNA (mtDNA) and amplified fragment length polymorphism (AFLP) markers, we found the highest genetic diversity in beetle populations from the central United States. The European populations clearly contained only a fraction of the genetic variability observed in North American populations. European populations show a significant reduction at nuclear markers (AFLPs) and are fixed for one mitochondrial haplotype, suggesting a single successful founder event. Despite the high vagility of the species and the reduction of genetic diversity in Europe, we found a similar, high level of population structure and low gene flow among populations on both continents. Founder events during range expansion, agricultural management with crop rotation, and selection due to insecticide applications are most likely the causes partitioning genetic diversity in this species.  相似文献   

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