Tests of Mendelian segregation and linkage-group relationships among 31 microsatellite loci in red drum, Sciaenops ocellatus     

Sten Karlsson  Liang Ma  Eric Saillant  John Rush Gold 《Aquaculture International》2007,15(5):383-391

Two families (parents and full-sibling progeny) of red drum (Sciaenops ocellatus) were assayed for genotypes at 31 nuclear-encoded microsatellites. Tests of expected Mendelian segregation at 29 of the microsatellites were non-significant following Bonferroni correction; occurrence of null alleles was inferred at the remaining two microsatellites. Nine of the 24 possible linkage groups (range 2–5 microsatellites per linkage group) were identified. Significant differences in recombination rates were found both between sexes and between families. The microsatellite linkage groups generated in this study represent the beginning of a genetic map for red drum, an economically important marine fish in the southeastern region of the United States of America.  相似文献   

Genetic diversity of the pea root pathogen Aphanomyces euteiches in Europe     

Carol Kälin  Anna Berlin  Agnese Kolodinska Brantestam  Mukesh Dubey  Anna-Kerstin Arvidsson  Paul Riesinger  Malin Elfstrand  Magnus Karlsson 《Plant pathology》2022,71(7):1570-1578

The oomycete pathogen Aphanomyces euteiches causes root rot in various legume species. In this study we focused on A. euteiches causing root rot in pea (Pisum sativum), thereby being responsible for severe yield losses in pea production. We aimed to understand the genetic diversity of A. euteiches in Europe, covering a north-to-south gradient spanning from Sweden, Norway and Finland to the UK, France and Italy. A collection of 85 European A. euteiches strains was obtained, all isolated from infected pea roots from commercial vining pea cultivation fields. The strains were genotyped using 22 simple-sequence repeat markers. Multilocus genotypes were compiled and the genetic diversity between individual strains and population structure between countries was analysed. The population comprising strains from Italy was genetically different and did not share ancestry with any other population. Also, strains originating from Finland and the eastern parts of Sweden were found to be significantly different from the other populations, while strains from the rest of Europe were more closely related. A subset of 10 A. euteiches strains from four countries was further phenotyped on two susceptible pea genotypes, as well as on one genotype with partial resistance towards A. euteiches. All strains were pathogenic on all pea genotypes, but with varying levels of disease severity. No correlation between the genetic relatedness of strains and virulence levels was found. In summary, our study identified three genetically distinct groups of A. euteiches in Europe along a north-to-south gradient, indicating local pathogen differentiation.  相似文献   

Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation     

Mahdavi J  Sondén B  Hurtig M  Olfat FO  Forsberg L  Roche N  Angstrom J  Larsson T  Teneberg S  Karlsson KA  Altraja S  Wadström T  Kersulyte D  Berg DE  Dubois A  Petersson C  Magnusson KE  Norberg T  Lindh F  Lundskog BB  Arnqvist A  Hammarström L  Borén T 《Science (New York, N.Y.)》2002,297(5581):573-578

Helicobacter pylori adherence in the human gastric mucosa involves specific bacterial adhesins and cognate host receptors. Here, we identify sialyl-dimeric-Lewis x glycosphingolipid as a receptor for H. pylori and show that H. pylori infection induced formation of sialyl-Lewis x antigens in gastric epithelium in humans and in a Rhesus monkey. The corresponding sialic acid-binding adhesin (SabA) was isolated with the "retagging" method, and the underlying sabA gene (JHP662/HP0725) was identified. The ability of many H. pylori strains to adhere to sialylated glycoconjugates expressed during chronic inflammation might thus contribute to virulence and the extraordinary chronicity of H. pylori infection.  相似文献   

Large-scale production of wheat and triticale double haploids through the use of a single-anther culture method     

S. Tuvesson    A. Ljungberg    N. Johansson  †  K.E. Karlsson    L. W. Suijs  J.P. Josset 《Plant Breeding》2000,119(6):455-459

A total of 257 parental wheat and 38 triticale lines were used for anther culture. On average, 2.1 green wheat haploids were obtained per spike. This response occurred irrespective of the origin of the material (Germany, France, Sweden or UK) and 5 years of testing. Triticale responded with 5.3 green haploids per spike. Using the criterion that one parental line should give at least one green haploid per spike in the screening experiment, green haploids were produced from 88 out of 91 F₁ wheat breeding combinations and from each of 21 F₁ and F₂ triticale breeding combinations. An average of 4.7 green plants were obtained per spike from the wheat production programme, while the triticale programme gave an average of 6.2 green plants per spike. A single medium supplemented with different hormones for anthers and embryos was used for culture of both crops.  相似文献