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61.
Leaf-specific thionins of barley (Hordeum vulgare L.) have been identified as a novel class of cell-wall proteins toxic to plant-pathogenic fungi and possibly involved in the defence mechanism of plants. The distribution of these polypeptides has been studied in the host-pathogen system of barley and Erisyphe graminis DC.f.sp. hordei Marchal (powdery mildew). Immunogold-labelling of thionins in several barley cultivars indicates that resistance or susceptibility may be attributed to the presence or absence of thionins at the penetration site in walls and papillae of epidermal leaf cells.All of the leaf-specific thionin genes are confined to the distal end of the short arm of chromosome 6 of barley. None of the genes for cultivarspecific resistance to powdery mildew which have previously been mapped on barley chromosomes are found close to this locus. 相似文献
62.
Danuta Dus Maciej Ugorski Wojciech Gorczyca Czeslaw Radzikowski 《Glycoconjugate journal》1989,6(3):355-365
125I-Wheat germ agglutinin (WGA) binding parameters of human urothelial cell lines of different grades of transformation (TGrll and TGrlll) were compared. The values of association constant (Ka) and the number of binding sites/cell for HCV29 (TGrll) cell line were about 3×106M–1 and over 4×107, respectively. Two TGrlll cell lines, HCV29T and Hu549 revealed lower values for Ka, and considerably higher numbers of binding sites/cell (about 3×108 and 2×108, respectively). Binding of125I-WGA to total cellular proteins resolved by SDS-PAGE and transferred to nitrocellulose showed multiple diffused bands in the range of 58–180 kDa. Some of these bands were characteristic for TGrll cells (124 kDa) or TGrlll cells (135 and 148 kDa).Abbreviations TGr
transformation grade
- WGA
wheat germ agglutinin
- sWGA
succinylated wheat germ agglutinin
- GlcNAc
N-acetyl-d-glucosamine
- BSA
bovine serum albumin
- SDS-PAGE
sodium dodecyl sulphate polyacrylamide gel electrophoresis 相似文献
63.
Addition of fruit cell wall extracts from two muskmelon cultivars into liquid media affected mycotoxin production by a strain of Myrothecium roridum pathogenic to muskmelon. Cell wall extracts from a susceptible cultivar (Iroquois) significantly increased toxin production while cell wall extracts from a resistant cultivar (Hales Best) significantly inhibited toxin production. Media containing 0.1 or 1.0 mg ml–1 stimulated toxin production more than media containing 10 or 100 mg ml–1 of cell wall extracts. Previous studies in our laboratory suggest that roridin E may be involved in virulence or pathogenicity of M. roridum; the present study indicates that cell wall polysaccharides as well as other materials present in cell wall preparations from susceptible host tissue provide a better substrate for toxin production than cell wall preparation from resistant host tissue. 相似文献
64.
The effect of tin and lead on levels of essential metals (Zn, Cu, Ca, Fe) in rabbit tissues was compared in relation to the route of administration. Animals received intraperitoneally, or per os, SnCl2 (2 mg Sn/kg) or Pb(CH3COO)2 (3.5 mg Pb/kg) every day for 5 d or for 1 mo. Copper, zinc, iron, and calcium were determined by AAS in the liver, kidneys, spleen, brain, bone marrow, and blood; lead and tin concentration were measured in the blood of animals. Tin and lead administered per os caused either no changes or the decreased concentration of endogenous metals in several tissues. The other route of administration (ip) of both metals generally contributed to the increased storage of essential elements. Blood tin levels of tin treated animals were only about less than or equal to 1/10 of blood lead concentrations of rabbits exposed to lead. 相似文献
65.
Kees W. Rodenburg Marcel J. A. de Groot Rob A. Schilperoort Paul J. J. Hooykaas 《Plant molecular biology》1989,13(6):711-719
In relation to the question which DNA form (single- or double-stranded) is transferred by Agrobacterium tumefaciens to plant cells, we studied the behaviour of single-stranded DNA, as compared to double-stranded DNA, when it is introduced into plant protoplasts by electroporation. To this end, we cloned a construct with a plant NPTII gene as well as a CAT gene in the M13 vectors tg130 and tg131. We found that both complementary single-stranded molecules gave rise to substantial CAT activity in plant protoplasts, suggesting that single-stranded DNA is converted into double-stranded DNA by the plant cell replication machinery. Unexpectedly, we found that single-stranded DNA leads to a 3–10 fold higher frequency of stable transformation (selection for kanamycin resistance) than double-stranded DNA. These results indicate that the use of single-stranded DNA might be considered in experiments in which optimal transformation frequencies are needed, e.g. with protoplasts form recalcitrant plant species.Abbreviations ss
single-stranded
- ds
double-stranded
- CAT
chloramphenicol acetyl transferase
- NPTII
neomycin phosphotransferase II
- RT
room temperature 相似文献
66.
Belinda Martineau H. Jane Smith Caroline Dean Pamela Dunsmuir John Bedbrook Laurens J. Mets 《Plant molecular biology》1989,13(4):419-426
We report the successful transformation, via Agrobacterium tumefaciens infection, and regeneration of two species of the genus Flaveria: F. brownii and F. palmeri. We document the expression of a C3 plant gene, an abundantly expressed ribulose 1,5-bisphosphate carboxylase/oxygenase small subunit gene isolated from petunia, in these C4 plants. The organ-specific expression of this petunia gene in Flaveria brownii is qualitatively identical to its endogenous pattern of expression. 相似文献
67.
Green cybrids with a new nucleus-chloroplast combination cannot be selected after protoplast fusion in the intersubfamilial Nicotiana-Solanum combination. As an approach to overcome the supposed plastomegenome incompatibility, a partial plastome transfer by genetic recombination has been considered. After fusions of protoplasts of a light-sensitive Nicotiana tabacum (tobacco) plastome mutant and lethally irradiated protoplasts of wild-type Solanum tuberosum (potato), a single green colony was recovered among 2.5×104 colonies. The regenerated plants had tobacco-like (although abnormal) morphology, but were normally green, and sensitive to tentoxin, demonstrating chloroplast markers of the potato parent. Restriction enzyme analysis of the chloroplast DNA (cpDNA) revealed recombinant, nonparental patterns. A comparison with physical maps of the parental cpDNA demonstrated the presence of a considerable part of the potato plastome flanked by tobacco-specific regions. This potacco plastome proved to be stable in backcross and backfusion experiments, and normally functional in the presence solely of N. tabacum nucleus. 相似文献
68.
Asplanchna sylvestrii does not discriminate between groups of Brachionus calyciflorus fed either the cyanobacterium Anabaena flos-aquae or a control diet of Euglena gracilis. We based our analysis on the observed probabilities of attack, capture and ingestion during encounters between predator and prey. While A. sylvestrii was very sensitive to brachionid size, we found no significant affects of prey diet on predatory behavior. Thus, cyanobacterial diet did not influence the short-term predation risk of B. calyciflorus exposed to an effective predator. On the other hand, matched cohorts of A. sylvestrii fed B. calyciflorus cultured on the cyanobacterium reproduced more slowly than those fed the same prey cultured on the control food. With prolonged sympatry, therefore, the long-term risk of Asplanchna predation may be reduced for Brachionus by the latter's consumption of cyanobacteria. 相似文献
69.
The presence of algae within the cases ofAgapetus fuscipes was investigated. Cases recognised as dirty or clean with the naked eye had more and less algal growth, respectively. Larvae in the former survived significantly longer when starved in the laboratory. It is suggested that the presence of algae within the cases would be of ecological advantage during periods of flood. 相似文献
70.
Richard T. Sawyer 《Mycopathologia》1990,109(2):99-109
The initial interaction of Candida albicans with pulmonary tissue of B6D2/F1 mice was investigated. The LD50 for mice challenged intravenously (IV) was approximately 3 × 105 yeasts, whereas the LD50 by the intratracheal (IT) route was in excess of 108 yeasts. Mice challenged IV died of progressive yeast growth in the kidneys. In contrast, mice challenged IT rapidly eliminated the entire inoculum by the first day after challenge. Resident pulmonary alveolar macrophages (PAM) killed upwards of 70% of C. albicans in an in vitro killing assay. At effector: target ratios favoring the effector cell population resident PAM were able to restrict the formation of yeast germ tubes to only 30% of the yeasts, whereas at equivalent ratios virtually all of the intracellular yeasts produced germ tubes. Evaluation of the ability of PAM, harvested from genetically different strains of inbred mice, to kill C. albicans in vitro showed that killing ability was a property of resident PAM from mice with the black 6 background. It was discovered that during the initial stages of infection in vivo, the expression of the F4/80 surface molecule was down regulated, and the expression of the Mac 1 surface molecule upregulated. There were no quantitative changes in expression of either Mac 2, Mac 3, Ly 5 or the 5C6 surface epitopes. Taken together, the data show that pulmonary tissue is quantitatively very resistant to C. albicans infection, because of the ability of resident PAM to rapidly phagocytize and kill yeasts. Killing of C. albicans by resident PAM may be a property of a subset of this mononuclear phagocyte population and was accompanied by alterations in the expression of surface molecules.Presented as part of the Everett S. Beneke Symposium in Mycology, May 27, 1988. 相似文献