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Mathew John Irwin Jeremy James Bougoure John David William Dearnaley 《Mycoscience》2007,48(4):231-239
In this study, we have identified the root-associated fungi of a common species of terrestrial orchid across its range in
eastern Australia. We have amplified and cloned fungal ITS DNA extracted from roots of 15 Pterostylis nutans R. Br. plants from six separate geographic localities. Sequencing and GenBank comparison demonstrated two species of Ceratobasidium fungi as the main fungal partners of the orchid. Uncommon fungal associates included homobasidiomycete species such as a
Gymnomyces sp. and a Tricholoma sp., Leptodontidium orchidicola, and an unidentified soil fungus. These results demonstrate that specificity for fungal partners occurs in P. nutans and reinforces the idea that conservation measures for endangered Australian orchids must include ex situ perpetuation of
fungal symbionts as well as plant material. 相似文献
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Further advances in orchid mycorrhizal research 总被引:4,自引:0,他引:4
Dearnaley JD 《Mycorrhiza》2007,17(6):475-486
Orchid mycorrhizas are mutualistic interactions between fungi and members of the Orchidaceae, the world’s largest plant family.
The majority of the world’s orchids are photosynthetic, a small number of species are myco-heterotrophic throughout their
lifetime, and recent research indicates a third mode (mixotrophy) whereby green orchids supplement their photosynthetically
fixed carbon with carbon derived from their mycorrhizal fungus. Molecular identification studies of orchid-associated fungi
indicate a wide range of fungi might be orchid mycobionts, show common fungal taxa across the globe and support the view that
some orchids have specific fungal interactions. Confirmation of mycorrhizal status requires isolation of the fungi and restoration
of functional mycorrhizas. New methods may now be used to store orchid-associated fungi and store and germinate seed, leading
to more efficient culture of orchid species. However, many orchid mycorrhizas must be synthesised before conservation of these
associations can be attempted in the field. Further gene expression studies of orchid mycorrhizas are needed to better understand
the establishment and maintenance of the interaction. These data will add to efforts to conserve this diverse and valuable
association. 相似文献
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Dearnaley John D.W.; Levina Natalia N.; Lew Roger R.; Heath I. Brent; Goring Daphne R. 《Plant & cell physiology》1997,38(9):985-999
We have investigated Ca2+-involving cell signaling, plasma membranepotentials and conductances and callose formation during earlystages of pollination of papillae of Brassica napus. Using fluorescenceimaging of calcium green-1, we found that application of a rangeof pollen types and controls all rapidly produced small localizedpeaks in papillar cytoplasmic [Ca2+]. This response was morefrequent in compatible than incompatible interactions and wascorrelated with subsequent hydration of the applied pollen grains,indicating that it may be a differential prerequisite of thecompatible signaling pathway leading to successful pollinations.In contrast, a slight trend to increased plasma membrane conductance(but with no indications of action potential-like responses)and also callose deposition in papillae adjacent to pollen grainsfollowed pollination in both SC and SI interactions, indicatingthat alterations in plasma membrane permeability and callosedeposition during early phases of pollination are not primarydeterminants of the fate of attempted pollinations.
2On leave of absence from A.N. Bach Institute of Biochemistry,Russian Academy of Sciences, Leninsky Pr., 33, Moscow, Russia,117071 相似文献
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Linkage analysis of chromosome 1q markers in 136 prostate cancer families. The Cancer Research Campaign/British Prostate Group U.K. Familial Prostate Cancer Study Collaborators. 总被引:2,自引:0,他引:2
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R A Eeles F Durocher S Edwards D Teare M Badzioch R Hamoudi S Gill P Biggs D Dearnaley A Ardern-Jones A Dowe R Shearer D L McLennan R L Norman P Ghadirian A Aprikian D Ford C Amos T M King F Labrie J Simard S A Narod D Easton W D Foulkes 《American journal of human genetics》1998,62(3):653-658
Prostate cancer shows evidence of familial aggregation, particularly at young ages at diagnosis, but the inherited basis of familial prostate cancer is poorly understood. Smith et al. recently found evidence of linkage to markers on 1q, at a locus designated "HPC1," in 91 families with multiple cases of early-onset prostate cancer. Using both parametric and nonparametric methods, we attempted to confirm this finding, in 60 affected related pairs and in 76 families with three or more cases of prostate cancer, but we found no significant evidence of linkage. The estimated proportion of linked families, under a standard autosomal dominant model, was 4%, with an upper 95% confidence limit of 31%. We conclude that the HPC1 locus is responsible for only a minority of familial prostate cancer cases and that it is likely to be most important in families with at least four cases of the disease. 相似文献
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Penetration of pollen tubes through stigmatic tissues in Brassica napus L. may involve the release of cell wall modifying enzymes from the pollen tube tip. We examined the expression of a pectin-degrading
polygalacturonase (PG) enzyme in unpollinated and early and late pollinated stigmas via immunoblotting and immuno-light microscopy
using a PG polyclonal antibody. Immunoblotting analysis indicated that PG enzyme was present at low levels in unpollinated
stigmas and at high levels in pollinated stigmas. The level of PG did not detectably increase between early and late pollinated
stigmas. Immuno-light microscopy demonstrated that PG enzyme was present in ungerminated pollen grains, stigmatic papillae
and in the tip of pollen tubes growing into the papillar wall. This latter evidence suggests that PG enzyme may play an important
role in papillar cell wall penetration during pollination although other interpretations of the role of pollen PG should not
be discounted.
Received: 9 November 2000 / Accepted: 7 December 2000 相似文献
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Two percent of men with early-onset prostate cancer harbor germline mutations in the BRCA2 gene 总被引:5,自引:0,他引:5
Edwards SM Kote-Jarai Z Meitz J Hamoudi R Hope Q Osin P Jackson R Southgate C Singh R Falconer A Dearnaley DP Ardern-Jones A Murkin A Dowe A Kelly J Williams S Oram R Stevens M Teare DM Ponder BA Gayther SA Easton DF Eeles RA;Cancer Research UK/Bristish Prostate Group UK Familial Prostate Cancer Study Collaborators;British Association of Urological Surgeons Section of Oncology 《American journal of human genetics》2003,72(1):1-12
Studies of families with breast cancer have indicated that male carriers of BRCA2 mutations are at increased risk of prostate cancer, particularly at an early age. To evaluate the contribution of BRCA2 mutations to early-onset prostate cancer, we screened the complete coding sequence of BRCA2 for germline mutations, in 263 men with diagnoses of prostate cancer who were =55 years of age. Protein-truncating mutations were found in six men (2.3%; 95% confidence interval 0.8%-5.0%), and all of these mutations were clustered outside the ovarian-cancer cluster region. The relative risk of developing prostate cancer by age 56 years from a deleterious germline BRCA2 mutation was 23-fold. Four of the patients with mutations did not have a family history of breast or ovarian cancer. Twenty-two variants of uncertain significance were also identified. These results confirm that BRCA2 is a high-risk prostate-cancer-susceptibility gene and have potential implications for the management of early-onset prostate cancer, in both patients and their relatives. 相似文献