RIBONUCLEASE ACTIVITY IN RUSTED WHEAT LEAVES

1961 ◽  
Vol 39 (4) ◽  
pp. 775-784 ◽  
Author(s):  
R. Rohringer ◽  
D. J. Samborski ◽  
C. O. Person
Keyword(s):  
Leaf Rust ◽  
Direct Evidence ◽  
Specific Activity ◽  
Host Tissue ◽  
Ribonuclease Activity ◽  
Rnase Activity ◽  
Rnase Inhibitor ◽  
Germination Medium ◽  
Wheat Leaves ◽  
Host Tissues

Extracts from primary leaves of Lee wheat were prepared at various days following inoculation with races of leaf rust and tested for ribonuclease (RNase) activity. As early as 24 hours after inoculation there was a marked increase in the specific activity of the enzyme in extracts of rusted host tissues. A further increase in activity was observed during later stages of infection, with the susceptible and resistant reacting tissue differing only in the degree of their response. Extracts from noninoculated control leaves exhibited a constant RNase activity throughout the period of observation. The germination medium and extracts from germinating uredospores contained comparatively little RNase activity. No direct evidence was obtained either for the possible release of the enzyme from particulate cellular fractions of the host tissue as a result of infection or for the removal of an RNase inhibitor in the host tissue responding to infection.

THE PHYSIOLOGY OF HOST-PARASITE RELATIONS: IX. FURTHER OBSERVATIONS ON THE ACCUMULATION OF RADIOACTIVE SUBSTANCES AT RUST INFECTIONS

1961 ◽  
Vol 39 (6) ◽  
pp. 1393-1407 ◽  
Author(s):  
Michael Shaw
Keyword(s):  
Specific Activity ◽  
Dry Weight ◽  
Insoluble Fraction ◽  
Pentose Phosphate ◽  
Accumulation Ratio ◽  
X Ray ◽  
Specific Activities ◽  
Leaf Segments ◽  
Wheat Leaves ◽  
Host Parasite

Wang (Can. J. Botany, 38, 635–642 (1960)) concluded that the accumulation of radioactivity observed on radioautographs at infection sites on rusted leaves fed with C14-labelled substances was 'apparent' rather than real. The ‘accumulation ratio’ is defined as the ratio of the specific activities (c.p.m./mg dry weight of intact tissue) of rust-infected to uninfected areas of infected leaves. Theoretical considerations relating to the radioautography of leaves labelled with C14 and to the measurement of ‘accumulation ratios’ by extraction of C14-labelled substances from rusted and uninfected segments of infected leaves, as well as experimental data, show that Wang's conclusion is not generally applicable.Experimentally, it was shown using polymethacrylate C14 sources that differences in distance between sources and X-ray film of the order of 100 μ had no effect on the intensity of autoradiographs. Rust-infected leaves, fed with radioactive glucose, were radiographed between X-ray plates. Localization of radioactivity at infection sites was observed on both ‘dorsal’ and ‘ventral’ radiographs, indicating a real accumulation per unit area. Ventral were more radioactive than dorsal surfaces. The main development of the fungus occurred on the former. Radioautography revealed that C14 from glucose-1-C14, glucose-6-C14, and uniformly labelled glucose fed to excised wheat leaves became localized at 10-day-old rust infections in 2 hours. ‘Accumulation ratios’ calculated from the specific activity of leaf segments remained close to 1.0 for at least 6 hours after introduction of the tracer, but increased to more than 2 after 24 hours. When ‘accumulation ratios’ were calculated from the specific activities of individual pustules (excised with a punch 1 mm in diameter) and interpustular disks, values greater than 1 were observed in 2 hours, thus confirming the results of autoradiography. Differences between the ‘accumulation ratios’ observed with glucose-6-C14 and glucose-1-C14 were consistent with an increased role of the pentose phosphate pathway at infection sites. Incorporation of C14 from uniformly labelled glucose into the alcohol-insoluble fraction of rusted leaf segments was 2.5-fold that in uninfected segments in 6 hours and 3.65-fold in 24 hours. The humin formed during hydrochloric acid hydrolysis accounted for approximately 50% of the activity of the alcohol-insoluble material. The ‘accumulation ratio’ for the alcohol-soluble material was only 1.56 after 24 hours.All the results support the view (Shaw and Samborski, Can. J. Botany, 34, 389–405 (1956)) that there is a quantitative, metabolically dependent accumulation of C14 from radioactive glucose at vigorous rust infections. The relative roles of fungus and host in this process are discussed briefly.

scholarly journals Relationship between formation of gametophore buds in the protonema of mosses and increase in ribonuclease activity

2015 ◽  
Vol 44 (3) ◽  
pp. 433-441
Author(s):  
M. Spychała ◽  
J. Schneider ◽  
A. Szeykowska
Keyword(s):  
Enzyme Activity ◽  
Early Phase ◽  
Ribonuclease Activity ◽  
Rnase Activity ◽  
Bud Formation ◽  
Factors Affecting ◽  
Spontaneous Formation

Changes in RNase activity similar to those accompanying cytokinin-induced formation of gametophore buds in mosses (a decrease in the early phase of bud formation and later an increase in enzyme activity) have also been found during spontaneous formation of gametophores in moss ontogenesis. Using various factors affecting the cytokinin-induced process of bud formation a correlation has been found between this process and the increase in RNase activity.

Modulation of cytosolic RNase activity by endogenous RNase inhibitor in rat vaginal epithelial cells on estradiol administration

FEBS Letters ◽  
1994 ◽  
Vol 343 (1) ◽  
pp. 11-14 ◽  
Author(s):  
K.Sridhar Rao ◽  
Ravi Sirdeshmukh ◽  
P.D. Gupta
Keyword(s):  
Epithelial Cells ◽  
Rnase Activity ◽  
Rnase Inhibitor ◽  
Vaginal Epithelial Cells

Morphogenetic properties of the skin axolotl limb regeneration

Development ◽  
1980 ◽  
Vol 58 (1) ◽  
pp. 265-288
Author(s):  
Jonathan M. W. Slack
Keyword(s):  
Limb Regeneration ◽  
Host Tissue ◽  
Tissue Formation ◽  
Cellular Composition ◽  
Posterior Half ◽  
Tail Bud ◽  
Threshold Theory ◽  
Anterior Side ◽  
Immunological Rejection ◽  
Host Tissues

A study has been made of the morphogenetic properties of anterior and posterior skin from the lower forelimb of the axolotl. The basic experiment consisted of a graft of a half cuff of skin from a donor to a host limb followed by a 2-week healing period, amputation through the graft, and a study of the resulting regenerate. Limbs with double posterior skin formed double posterior regenerates and, in contrast, limbs with double anterior skin formed normal or slightly hypomorphic regenerates. Posterior skin from post-metamorphic animals had a similar but weaker effect to that from ordinary axolotls. Immunological rejection of allografts could be completely avoided if the donor limb was transplanted to the flank of the host when both were at the stage of tail-bud embryos, and the skin graft was later carried out between the supernumerary limb and one of the host limbs. This technique was used to show that immunological rejection does not affect the formation of duplicates from the limbs with double posterior skin, and to facilitate the studies of the cellular provenance of the regenerate. The cellular composition of duplicate regenerates was studied by using both triploid donors and triploid hosts. It was shown that the posterior side of the duplications consisted wholly of host tissue and the anterior side consisted of mixed donor and host tissue. Formation of the duplicated regenerate therefore seems to involve positional reprogramming of both donor and host tissues together with metaplasia of the donor tissue. It was not possible to inhibit the duplication-inducing property of posterior skin by treatment with a variety of enzymes. A model based on the serial threshold theory of regeneration is advanced to explain the results.This model successfully accounts for the observed non-equivalence of anterior and posterior skin, and also explains the different regeneration behaviour of anterior and posterior half limbs, the limited regeneration of double anterior limbs, and the pattern expansion and contraction shown by regenerates from double posterior limbs.

scholarly journals Destruction of Immature Erythrocytes Measured by Bilirubin Excretion

Blood ◽  
1969 ◽  
Vol 33 (5) ◽  
pp. 717-726
Author(s):  
KIYOYASU NAGAI ◽  
EIZO KAKISHITA
Keyword(s):  
Normal State ◽  
General Circulation ◽  
Direct Evidence ◽  
Specific Activity ◽  
Total Radioactivity ◽  
Sprague Dawley ◽  
Wistar Strain ◽  
Bilirubin Excretion ◽  
Sprague Dawley Rats ◽  
Bile Fistula

Abstract The change in radioactivity of bilirubin with time was measured after injection of glycine 2-14C into rats with a bile fistula. The total radioactivity and specific activity of bilirubin were abnormally high in rats of which erythropoiesis was increased following hemorrhage. When the newly formed erythrocytes labeled with glycine 2-14C in the peak of reticulocytosis were transfused into rats with a bile fistula, the excretion of labeled bilirubin increased rapidly. The amount of newly formed erythrocytes destroyed within 7 days after transfusion into normal animals was calculated as 4.4 per cent of the total erythrocytes formed during maximum reticulocytosis and 1.1 per cent of those formed in the normal state in Sprague Dawley rats, while in the Wistar strain, the values were 13.4 per cent and 2.2 per cent, respectively. These results provide direct evidence for increased production of short-lived erythrocytes during enhanced erythropoiesis, and the hemolysis of newly formed erythrocytes soon after they reach the general circulation may contribute to the production of shunt bilirubin.

Impurity in RNA Preparations which Inactivates RNase Inhibitor and Increases Alkaline RNase Activity.

1962 ◽  
Vol 109 (4) ◽  
pp. 804-808 ◽  
Author(s):  
H. J. Eichel
Keyword(s):  
Rnase Activity ◽  
Rnase Inhibitor

Mast cell response during the early phase of tuberculosis: an electron-microscopic study

1977 ◽  
Vol 23 (9) ◽  
pp. 1245-1251 ◽  
Author(s):  
Samuel Ratnam ◽  
Shobhitha Ratnam ◽  
B. K. Puri ◽  
Saroj Chandrasekhar
Keyword(s):  
Mast Cell ◽  
Mycobacterium Tuberculosis ◽  
Electron Microscope ◽  
Host Tissue ◽  
Tuberculous Infection ◽  
Electron Microscopic ◽  
Morphological Alterations ◽  
Dense Bodies ◽  
Large Numbers ◽  
Host Tissues

Guinea pig lungs were infected with Mycobacterium tuberculosis by intratracheal route and examined under electron microscope to investigate the morphological alterations of the organisms, if any, and the response of the host tissue. The bacilli showed no changes in their morphology, while the host tissues revealed several cells containing many electron-dense intracytoplasmic granules. These cells were predominantly seen during the 1st week of infection. The electron-dense bodies of these cells may be the ones observed by earlier workers and suggested to be the altered forms of tubercle bacilli. The present investigation, however, revealed them to be the granules of the mast cells. These cells were observed to respond to tuberculous infection during the first few days by appearing in large numbers crowded with intracytoplasmic granules and soon disintegrating as the result of subsequent degranulation. The above observation is presented and its significance discussed.

Ectopic induction and reorganization of Wnt-1 expression in quail/chick chimeras

Development ◽  
1994 ◽  
Vol 120 (12) ◽  
pp. 3379-3394 ◽  
Author(s):  
L. Bally-Cuif ◽  
M. Wassef
Keyword(s):  
Expression Profile ◽  
Host Tissue ◽  
Host Embryo ◽  
Positive Line ◽  
Host Tissues

When grafted ectopically into the diencephalon of a chick host embryo, a portion of met-mesencephalon straddling the met-mesencephalic constriction has the capacity to induce En-2 expression in the surrounding host tissue. Subsequently, tectal and cerebellar structures, composed of both host and grafted cells, are reconstructed in this ectopic location at the expense of the host diencephalon. Previous experiments indicated that the induction of En-2 was correlated with Wnt-1 expression within the graft. The aim of the present study was: (i) to determine whether Wnt-1 expression was spatially regulated within the graft, (ii) to investigate whether host Wnt-1-expressing cells were also involved in the ectopic met-mesencephalic development and, if so, (iii) to localize these Wnt-1-positive domains in relation to the patterning of the ectopically developing met-mesencephalic territory. We studied the expression profile of Wnt-1, in relation with that of other positional markers, in quail/chick chimeras where various portions of met-mesencephalon had been grafted into the diencephalon. We found that Wnt-1 expression was reorganized within the graft, and that it was also induced in the host in contact with the graft. Moreover, these ectopic expressions of Wnt-1, in both the grafted and the surrounding host tissues, were organized in concert to form a continuous positive line at the host/graft junction, the location of which depended on the precise origin of the graft. Finally, we found that this line was frequently located at the limit between territories expressing different positional markers. We propose that Wnt-1 expression is turned on at the junction between domains of different phenotypes, and may be used as a border to stabilize these adjacent differently committed territories.

Peroxidase activity in healthy and leaf-rust-infected wheat leaves

1972 ◽  
Vol 11 (2) ◽  
pp. 547-551 ◽  
Author(s):  
Lowell B. Johnson ◽  
Bryce A. Cunningham
Keyword(s):  
Leaf Rust ◽  
Peroxidase Activity ◽  
Wheat Leaves

Content and Metabolism of Indole-3-acetic Acid (IAA) in Healthy and Rust-Infected Wheat Leaf Segments

1986 ◽  
Vol 41 (11-12) ◽  
pp. 1023-1031
Author(s):  
Gertrud Wiese ◽  
Hans J. Grambow
Keyword(s):  
Acetic Acid ◽  
Stem Rust ◽  
Main Part ◽  
Rust Fungus ◽  
Rapid Exchange ◽  
Germination Medium ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Indole 3 Acetic Acid ◽  
Iaa Conjugates

Abstract The content of IAA in stem rust-infected susceptible wheat leaves shows a highly pronounced maximum 5-6 days after inoculation, shortly prior to the onset of sporulation. This auxin increase can not only be caused by a reduced degradation of IAA. Considerable amounts of IAA are also found in urediospores and germlings; the IAA is in part released by them into the germination medium. IAA applied exogenously to wheat leaves is channelled into two different degradation path­ways: (a) into the peroxidase-catalysed decarboxylation which leads to indole-3-methanol and subsequent products as well as into (b) a non-decarboxylative path which leads to a number of oxindolic compounds. Furthermore, IAA conjugates such as IAAglc and IAAsp are formed. The formation of the products is characteristically dependent upon the concentration of the IAA applied. In rust fungus-infected wheat leaves, all IAA metabolites occur which are known in healthy leaves. The mode of their formation after “feeding” of radioactively-labelled IAA leads to the conclusion that the main part of the IAA in the infected leaves is present in a pool which does not permit a rapid exchange with the IAA taken up. The results lead to the hypothesis that IAA is present, to a major extent, in the structures of the fungus and is probably also produced by it.

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