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.

INCORPORATION OF P32 INTO RIBONUCLEIC ACID OF RUSTED WHEAT LEAVES

1961 ◽  
Vol 39 (2) ◽  
pp. 263-267 ◽  
Author(s):  
R. Rohringer ◽  
R. Heitefuss
Keyword(s):  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Leaf Material ◽  
Resistant Reaction ◽  
Wheat Leaves ◽  
Host Parasite ◽  
Parasite Complex ◽  
Metabolic Significance

P32-labelled orthophosphate was fed to rusted and non-rusted wheat leaves. The ribonucleic acid (RNA) isolated from this material was purified and its specific activity determined. The specific activity of RNA from susceptible reacting tissue had increased 60–208% [Formula: see text] days after inoculation, but [Formula: see text] days after inoculation it was not markedly different from RNA preparations of uninoculated leaf material, indicating an increase and eventual decline in RNA synthesis of the host–parasite complex. In the resistant reaction incorporation of P32 into the RNA was unaltered by infection. The possible metabolic significance of these observations is discussed.

Molybdenum nutrition of isolates of four Aspergillus species

1986 ◽  
Vol 32 (7) ◽  
pp. 557-561 ◽  
Author(s):  
S. C. Agarwala ◽  
C. Chatterjee ◽  
N. Nautiyal ◽  
C. P. Sharma
Keyword(s):  
Acid Phosphatase ◽  
Nitrate Reductase ◽  
Aspergillus Flavus ◽  
Soluble Protein ◽  
Specific Activity ◽  
Succinic Dehydrogenase ◽  
Dry Weight ◽  
Catalase Peroxidase ◽  
Conidial Formation ◽  
Specific Activities

The molybdenum requirement for growth and conidial formation by Aspergillus flavus, A. terreus, and A. sulphureus was found to be 0.2 ppb, which was one-fifth that of an A. niger isolate. Molybdenum deficiency depressed growth, conidial formation, dry weight, soluble protein, and the specific activities of nitrate reductase, succinic dehydrogenase, and aconitase in all the isolates of Aspergillus studied, but the specific activities of catalase and peroxidase were depressed only in isolates of A. niger, A. terreus, and A. flavus. Also, molybdenum deficiency stimulated the specific activities of acid phosphatase and ribonuclease in the A. flavus isolate, although the specific activities of these enzymes decreased in other isolates. Eighteen hours after the addition of molybdenum (5 ppb) to molybdenum-deficient (0.02 ppb) cultures of A. niger, the specific activities of catalase, peroxidase and succinic dehydrogenase were restored in the absence of cycloheximide, while the specific activity of nitrate reductase was recovered even in the presence of the inhibitor. There was no effect on the specific activities of aconitase and acid phosphatase following the addition of molybdenum to molybdenum-deficient cultures of A. niger.

CELL BIOLOGICAL ASPECTS OF HOST–PARASITE RELATIONS OF OBLIGATE FUNGAL PARASITES

1967 ◽  
Vol 45 (8) ◽  
pp. 1205-1220 ◽  
Author(s):  
Michael Shaw
Keyword(s):  
Pentose Phosphate ◽  
Valuable Insight ◽  
Infection Structures ◽  
Host Parasite Interactions ◽  
Biological Studies ◽  
Apparent Decrease ◽  
Fungal Parasites ◽  
Wheat Leaves ◽  
Inoculation Treatment ◽  
Host Parasite

Obligate parasitism is defined, and the principles involved in host–parasite interactions are briefly described. In the absence of host tissue, the germination and development of rust uredospores stops with the formation of infection structures. Interaction with the host results in further development of the parasite. It has been shown that in rust-infected tissue there are increases in respiration rate, in the activity of the pentose phosphate pathway, and in the concentrations of many constituents, including RNA and auxin. Such studies have usually been conducted at relatively late stages in disease development, but there is evidence to indicate that critical interactions between host and parasite occur very shortly after inoculation. Valuable insight has recently come from electron microscope and other cell-biological studies in the early stages of the establishment of rust infections. In particular, quantitative cytophotometry has demonstrated an apparent decrease in histones and an increase in RNA in the mesophyll nuclei of rust-infected wheat leaves 48 h after inoculation. Studies on the effect of actinomycin D on the development of flax rust also point to the rapidity with which host–parasite interactions occur. This antibiotic (2.5 mg/l) does not inhibit uredospore germination. It does inhibit the development of rust infections on the host, but only if the treatment is given before 5 or 6 h after inoculation. Treatment after this stage is not effective.Attention is drawn to the possible importance of the apparent absence of nucleoli in uredospore nuclei and to the possibility that uredospore germination and the differentiation of infection structures may occur without the formation of new ribosomes. It is also suggested that successful establishment of obligate fungal parasites or their hosts may involve the derepression of host DNA and the synthesis of new proteins.

Cartilage fucoproteins with sites for cross-linking by transglutaminase

1987 ◽  
Vol 65 (4) ◽  
pp. 280-285 ◽  
Author(s):  
J. Michael Bowness
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
High Performance ◽  
Specific Activity ◽  
Weight Fraction ◽  
Dry Weight ◽  
Insoluble Fraction ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Collagen Iii

Slices of various types of cartilage were incubated with either L-[6-3H]fucose or [1,4-3H(N)]putrescine. Homogenization of the slices and fractionation of the homogenates showed for both labels that an insoluble collagenase-resistant fraction had the highest specific activity (dpm/mg dry weight). Examination of an exhaustive proteolytic digest of this insoluble fraction by ion-exchange high performance liquid chromatography showed the presence of γ-glutamyl[3H]putrescine. Chromatography of solubilized [3H]fucoprotein fractions showed the presence of several low molecular weight peaks, as well as high molecular weight material. Incubation of [3H]fucoprotein extracts with transglutaminase increased the high molecular weight peaks and decreased the low molecular weight ones. Incubation of the cartilage slices with L-[3H]fucose plus 0.5 mM dansylcadaverine, an inhibitor of transglutaminase, caused a decrease in the insoluble and high molecular weight fraction relative to the low molecular weight peaks. It is hypothesized that this is due to inhibition of cross-link formation between fucoprotein components of the cartilage which are transglutaminase substrates. One major low molecular weight peak, which labels with both fucose and putrescine, corresponds in size with the 15 000 subunit of collagen III aminopropeptide, which is known to be a substrate for transglutaminase.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: III. THE PATTERN OF RESPIRATION IN RUSTED AND MILDEWED CEREAL LEAVES

1957 ◽  
Vol 35 (3) ◽  
pp. 389-407 ◽  
Author(s):  
Michael Shaw ◽  
D. J. Samborski
Keyword(s):  
Oxygen Uptake ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Pentose Phosphate ◽  
Host Tissue ◽  
Infected Tissue ◽  
Short Term ◽  
Pasteur Effect ◽  
Host Parasite ◽  
Leaf Disks

The first leaves of resistant (Khapli) and susceptible (Little Club) species of wheat were heavily inoculated with stem rust (Race 15B). After infection, oxygen consumption per unit dry weight increased two- to three-fold and then fell off again. The R.Q. remained close to 1.0 until the respiratory peak was reached and then declined to 0.80 to 0.85, at least in Khapli. The INR/OR values (approximately 1.2) suggest the operation of a Pasteur effect in uninfected tissue. With infected tissue there was little or no increase in NR as oxygen uptake rose and the INR/OR values declined steadily to about 0.2 to 0.3. The oxygen uptake of rusted, mildewed, and uninfected tissue was stimulated by 2,4-dinitrophenol. The percentage stimulation was reduced by infection. The smallest percentage stimulations were observed, after the respiratory peak had been passed, with infected tissue of Khapli, in which chlorosis and other degenerative changes developed quickly. The actual increases in oxygen uptake obtained with 10−5 M dinitrophenol were about the same for infected as for uninfected tissue, but, in Khapli, fell sharply after the respiratory maximum. Leaf-disks were incubated separately with glucose-1-C14, glucose-6-C14, and glucose-UL-C14, and the relative activities of the carbon dioxide produced were measured. The C6/C1 ratio showed a significant negative correlation with the oxygen uptake of rusted tissue, suggesting that the pentose phosphate pathway is of increased importance in infected tissue. The C6/C1 ratio was also reduced in the host tissue at the loci of mildew infections. In short term experiments dinitrophenol raised the C6/C1 ratio. The significance of the results is discussed and it is concluded that infection with rust or mildew not only raises the respiration rate but alters the pathway of respiration in the host tissue.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: XIV. THE EFFECT OF RUST INFECTION ON THE NUCLEIC ACID CONTENT OF WHEAT LEAVES

1964 ◽  
Vol 42 (11) ◽  
pp. 1531-1540 ◽  
Author(s):  
W. A. Quick ◽  
Michael Shaw
Keyword(s):  
Dry Weight ◽  
Weight Basis ◽  
Nucleic Acid Content ◽  
Fresh Weight ◽  
Fresh Weight Basis ◽  
Rust Infection ◽  
Dna And Rna ◽  
Fungal Dna ◽  
Wheat Leaves ◽  
Host Parasite

The increase in respiration in rust-infected leaves of Little Club wheat was followed and paralleled by an increase in RNA per gram dry weight. The massive increase in dry weight of infected leaves in the later stages of rust development (9–12 days after inoculation) sometimes obscured the increase in RNA when RNA was expressed on a dry weight but not when it was expressed on a fresh weight basis. There was no increase in RNA in rust-infected Khapli. Rust infection had no effect on DNA per gram dry weight in Little Club or Khapli, but DNA per gram fresh weight increased slightly (15%) in Little Club, indicating the synthesis of fungal DNA. Infection had little effect on the protein content of Little Club but markedly lowered that of Khapli. The results are discussed in relation to earlier cytochemical determinations of DNA and RNA in infected tissue.

An International Collaborative Study to Investigate Standardisation of Hirudin Potency

1993 ◽  
Vol 69 (05) ◽  
pp. 430-435 ◽  
Author(s):  
Colin Longstaff ◽  
Man-Yu Wong ◽  
Patrick J Gaffney
Keyword(s):  
Specific Activity ◽  
Collaborative Study ◽  
Residual Activity ◽  
Quality Standard ◽  
Upper Limit ◽  
Assay Procedure ◽  
Specific Activities ◽  
International Collaborative ◽  
Range Of Values ◽  
International Collaborative Study

SummaryAn international collaborative study has been carried out to investigate the reproducibility of hirudin assays in 13 laboratories using four recombinant hirudins and one natural, sulphated product. A simple assay procedure was proposed involving the titration of α-thrombin with inhibitor and measurement of residual activity using a chromogenic substrate. A standard α-thrombin preparation was supplied to ensure that this reagent was of uniform quality throughout the study. The method appeared to present no difficulties and laboratories reported similar potencies for the 5 hirudin samples, in line with expected values. This gave 200–222 Thrombin Inhibitory Units/ampoule (TIU/ampoule) of lyophilised hirudin, with geometric coefficient of variation (gcv) values ranging from 10.15–15.97%. This corresponds to specific activities of approximately 14,300–15,900 TIU/mg protein. This is close to the upper limit of previously reported values of specific activity. We conclude that the precision of this determination compared with the wider range of values in the literature (8,000–16,000 thrombin inhibitory units [TIU]/mg) results from the use of good quality standard α-thrombin by all laboratories. This study has important implications for hirudin standardisation.

scholarly journals Gut Digestive Function and Microbiome after Correction of Experimental Dysbiosis in Rats by Indigenous Bifidobacteria

2021 ◽  
Vol 9 (3) ◽  
pp. 522
Author(s):  
Lyudmila V. Gromova ◽  
Elena I. Ermolenko ◽  
Anastasiya L. Sepp ◽  
Yulia V. Dmitrieva ◽  
Anna S. Alekseeva ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Digestive Enzymes ◽  
Specific Activity ◽  
Control Group ◽  
Enteropathogenic Escherichia Coli ◽  
Beneficial Bacteria ◽  
Opportunistic Bacteria ◽  
Dyspeptic Symptoms ◽  
Specific Activities ◽  
Impaired Motor Function

In recent years, great interest has arisen in the use of autoprobiotics (indigenous bacteria isolated from the organism and introduced into the same organism after growing). This study aimed to evaluate the effects of indigenous bifidobacteria on intestinal microbiota and digestive enzymes in a rat model of antibiotic-associated dysbiosis. Our results showed that indigenous bifidobacteria (the Bf group) accelerate the disappearance of dyspeptic symptoms in rats and prevent an increase in chyme mass in the upper intestine compared to the group without autoprobiotics (the C1 group), but significantly increase the mass of chyme in the colon compared to the C1 group and the control group (healthy animals). In the Bf group in the gut microbiota, the content of opportunistic bacteria (Proteus spp., enteropathogenic Escherichia coli) decreased, and the content of some beneficial bacteria (Bifidobacterium spp., Dorea spp., Blautia spp., the genus Ruminococcus, Prevotella, Oscillospira) changed compared to the control group. Unlike the C1 group, in the Bf group there was no decrease in the specific activities of maltase and alkaline phosphatase in the mucosa of the upper intestine, but the specific activity of maltase was decreased in the colon chyme compared to the control and C1 groups. In the Bf group, the specific activity of aminopeptidase N was reduced in the duodenum mucosa and the colon chyme compared to the control group. We concluded that indigenous bifidobacteria can protect the microbiota and intestinal digestive enzymes in the intestine from disorders caused by dysbiosis; however, there may be impaired motor function of the colon.

scholarly journals THE Ah PHENOTYPE. SURVEY OF FORTY-EIGHT RAT STRAINS AND TWENTY INBRED MOUSE STRAINS

Genetics ◽  
1982 ◽  
Vol 100 (1) ◽  
pp. 79-87
Author(s):  
Daniel W Nebert ◽  
Nancy M Jensen ◽  
Hisashi Shinozuka ◽  
Heinz W Kunz ◽  
Thomas J Gill
Keyword(s):  
Specific Activity ◽  
Inbred Mouse ◽  
Inbred Mouse Strain ◽  
Mouse Strains ◽  
Ah Receptor ◽  
Inbred Mouse Strains ◽  
Sprague Dawley ◽  
Rat Strains ◽  
Specific Activities ◽  
Inbred Rat

ABSTRACT Forty-four inbred and four randombred rat strains and 20 inbred mouse strains were examined for their Ah phenotype by determining the induction of liver microsomal aryl hydrocarbon (benzo[a]pyrene) hydroxylase activity (EC 1.14.14.1) by intraperitoneal treatment with either β-naphthoflavone or 3-methylcholanthrene. All 48 rat strains were found to be Ah-responsive. The maximally induced hydroxylase specific activities of the ALB/Pit, MNR/Pit, MR/Pit, SHR/Pit, and Sprague-Dawley strains were of the same order of magnitude as the basal hydroxylase specific activities of the ACI/Pit, F344/Pit, OKA/Pit, and MNR/N strains. Six of the 20 mouse strains were Ah-nonresponsive (i.e. lacking the normal induction response and presumably lacking detectable amounts of the Ah receptor). The basal hydroxylase specific activities of the BDL/N, NFS/N, STAR/N, and ST/JN mouse strains were more than twice as high as the maximally induced hydroxylase specific activity of the CBA/HT strain.——To date, 24 Ah-nonresponsive mouse strains have been identified, out of a total of 68 known to have been characterized. The reasons for not finding a single Ah-nonresponsive inbred rat strain—as compared with about one Ah-nonresponsive inbred mouse strain found for every three examined—remain unknown.

METHODS OF PROTEIN EXTRACTION FROM NEUROSPORA CRASSA

1964 ◽  
Vol 10 (1) ◽  
pp. 29-35 ◽  
Author(s):  
G. J. Stine ◽  
W. N. Strickland ◽  
R. W. Barratt
Keyword(s):  
Glutamic Acid ◽  
Neurospora Crassa ◽  
Total Protein ◽  
Extraction Method ◽  
Protein Extraction ◽  
Specific Activity ◽  
Dry Weight ◽  
Acid Dehydrogenase ◽  
Total Enzyme

Nine methods for disrupting the mycelium of Neurospora crassa have been compared. Protein percentages are calculated per gram dry weight of mycelium. A TPN-specific glutamic acid dehydrogenase was extracted and the efficiency of each extraction method is given as total enzyme extracted and specific activity. In terms of total protein, total enzyme, and practicality of the method, the Hughes Press, the French Press and the Raper–Hyatt Press were found to be the most efficient. The advantages and limitations of each method are considered.

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