Biochemical properties of the pathogenesis-related proteins from tobacco     

J. F. Antoniw  R. F. White 《European journal of plant pathology / European Foundation for Plant Pathology》1983,89(6):255-264

This review describes the discovery and identification of the pathogenesis-related proteins (PRs) from tobacco. In crude leaf extracts the PRs are distinguished from the proteins in uninfected plants by their solubility at pH 3, resistance to a range of proteases, and mobility in polyacrylamide gels upon electrophoresis (PAGE) in non-denaturing conditions. PAGE has been used as a qualitative and semi-quantitative assay for PRs, and their migration in gels made from different acrylamide concentrations has been used to identify charge and size isomers and electrophoretically identical PRs in different tobacco cultivars. The subunit composition and molecular weight (mol. wt) of the four PRs identified first in Xanthi-nc were determined by SDS-PAGE; staining the gels has shown that these same four proteins in Samsun NN did not contain carbohydrate, lipid or nucleic acid, nor were they isozymic forms of twenty five enzymes known to increase in activity following infection with TMV. Evidence suggests that most of the PRs in Xanthi-nc and Samsun NN are extracellular.The purification of several PRs from Xanthi-nc, Samsun NN and other tobaccos is described, as well as their mol. wt, subunit and amino acid composition. PRs 1a, b and c consist of a single polypeptide and have similar mol. wt and amino acid compositions. Antisera prepared against purified Xanthi-nc b₁ protein have been used to determine serological relationships between PRs and form the basis of a very sensitive quantitative assay using ELISA. The regulation of synthesis of some PRs has been shown to involve translational control.  相似文献   

The genetic control of antibody formation     

R K Seide  J M Kehoe 《Veterinary immunology and immunopathology》1983,4(1-2):3-42

Studies of the molecular biology of lymphoid cells have markedly increased our understanding of how millions of different antibodies can be synthesized by a single animal. To date, the most detailed understanding has been achieved for the mouse, primarily because of the relatively greater experimental availability of this species. These studies, as well as those involving other species, have shown that the complete genes for antibody polypeptide chains are assembled from disparate genetic elements which are originally widely separated in the genome. The assembly process itself, together with the coding information present in the germ line genetic elements, contributes to the diversity of structure (and thus combining specificities) shown by mature antibody molecules. Specifically, the diversity of structure characteristic of antibody variable regions is due to three distinct mechanisms: innate variability of germ line genes; mismatching of individual gene segments during their somatic rearrangement leading to junctional diversity; and somatic mutation in variable region genetic material during or after the rearrangement. These processes lead to the wide array of combining specificities that permit the humoral immune system of a mature animal to interact with essentially any non-self antigen which it encounters. Complex genetic rearrangements are also responsible for the class switching phenomenon long known to be characteristic of the humoral immune response. A form of homologous recombination between constant region genes, possibly mediated by specific "switching" enzymes, is now believed to be involved in this phenomenon. It is also currently believed that the restriction of gene rearrangement processes to one of the two possible chromosomes of a diploid pair in each cell is responsible for the phenomenon of allelic exclusion that has long been associated with the normal functioning of mammalian B-cells.  相似文献   

Rubbery Rot (Oospora lactis (Fres.) Sacc.) of Potatoes     

U. R. Humphreys-Jones   《Plant pathology》1969,18(4):186-187

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TRANSLOCATION OF AMINOTRIAZOLE AND DALAPON IN AG ROPY RON REPENS (L.) BEAUV.     

K. LUND-HÖIE  A. BYLTERUD 《Weed Research》1969,9(3):205-210

Summary. Tracer studies using single drops of solutions containing 3–amino-1,2,4–triazole-5–¹⁴C (aminotriazole-¹⁴C) or 2,2–dichloropropionic acid-2–¹⁴C (datapon-¹⁴C) revealed that in couch plants (Agropyron repens (L.) Beauv.) growing under field conditions in the autumn and at the stage where the aerial shoots were 40–50 cm long, both compounds moved in both symplast and apoplast. Dalapon was less mobile in the symplast than aminotriazole and only negligible amounts of dalapon were translocated to the rhizomes. The nodes of the treated shoots appeared to act as barriers to translocation, a phenomenon more pronounced for dalapon than for aminotriazole.
Application to a basal green leaf led to a more uniform distribution of the compounds within plants and rhizomes than when the application was made to the youngest fully-expanded leaf.
In couch plants with aerial shoots 10–15 cm long treated in the stubble, the distribution of both aminotriazole and dalapon was mainly restricted to the treated shoots. Even 15 days after application only trace amounts of radioactivity could be found in the rhizomes and untreated shoots.  相似文献   

THE ADSORPTION OF LINURON, ATRAZINE AND EPTC BY MODEL ALIPHATIC ADSORBENTS AND SOIL ORGANIC PREPARATIONS     

R. J. HANCE 《Weed Research》1969,9(2):108-113

Summary. Model adsorbents were prepared by treating cellulose phosphate powder with a series of alkyltrimethylammonium compounds in which the size of the alkyl group was varied from C₈to C₁₈. The adsorption of linuron, atrazine and EPTC by these materials was found to increase logarithmically with increasing chain length. The extent of the adsorption was large compared with the adsorption of these herbicides by a humic acid and by a preparation made by removing the bulk of the inorganic constituents of a peat soil with a mixture of HCl and HF. Since soil organic matter is thought to contain alkyl groups, it is concluded that the possible influence of such groups should be considered in any discussion of the mechanisms involved in the adsorption of organic molecules by soils.
Adsorption du linuron, de I'atrazine de l'EPTC par des adsorbants de la série aliphatique et des préparations organiques de sol  相似文献   

Relationship of some blood components to morbidity and mortality in auction calves     

G E Staples  M F Andrews  R M Parsons  P McIlwain 《The Cornell veterinarian》1969,59(2):313-325

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Effect of hyperimmunization with semen antigens on electrophoretic pattern of goat serum     

V D Goel  B K Soni  D Sharma 《The Indian veterinary journal》1969,46(3):218-223

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Mixed hemadsorption technique for study of avian leukosis-sarcoma viruses: studies with avian leukosis viruses     

C R Rossi  D Segre 《American journal of veterinary research》1969,30(5):831-836

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Morphological description of cell cultures containg a Type-II (Marek's) leukosis virus (JM strain)     

K Anderson  M Sevoian 《Avian diseases》1969,13(3):470-485

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Hydrocyanic acid poisoning in cattle caused by grazing on sugar cane (Saccharum officinarum) and supplemental feeding of fruits of the algarrobo tree (Prosopis juliflora)     

H S Seifert  K A Beller 《Berliner und Münchener tier?rztliche Wochenschrift》1969,82(5):88-91

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