scholarly journals Oxidative Metabolism in ‘Valencia’ Sweet Orange (Citrus sinensis Osbeck) Abscission Zone Tissue Treated with the Abscission Agent 5-Chloro-3-Methyl-4-Nitro-1H-Pyrazole

HortScience ◽  
2016 ◽  
Vol 51 (4) ◽  
pp. 377-382 ◽  
Author(s):  
Naveen Kumar ◽  
Robert C. Ebel
Keyword(s):  
Oxidative Metabolism ◽  
Indole Acetic Acid ◽  
Specific Activity ◽  
Sweet Orange ◽  
Malonic Dialdehyde ◽  
Citrus Fruit ◽  
Abscission Zone ◽  
Specific Activities ◽  
Orange Trees

5-Chloro-3-methyl-4-nitro-1H-pyrazole (CMNP) is an abscission agent, standardized for the mechanical harvesting of late season ‘Valencia’ sweet oranges in Florida. This work was conducted to investigate the role of CMNP to induce oxidative stress in the abscission zone (AZ) of ‘Valencia’ sweet orange. Fully mature ‘Valencia’ sweet orange trees in a commercial grove were sprayed with 2.0 mm of CMNP. The experiment was repeated three times during the Apr.–May 2013 harvest season. Fruit were harvested at 0, 1, 2, and 3 days after CMNP application. Hydrogen peroxide (H2O2) concentration and malonic dialdehyde (MDA) concentration, as well as superoxide dismutase (SOD), ascorbate peroxidase (APOD), glutathione reductase (GR), peroxidase (POD), and lipoxygenase (LOX) specific activities were measured 0, 1, 2, and 3 days after CMNP treatment (DAT). Rate of lipid peroxidation remains unchanged throughout the abscission period. However, LOX activity increased 1 DAT in AZ of treated fruit, which might produce jasmonic acid (JA), known to promote abscission in citrus. Levels of H2O2 were similar in the AZ of control and treated fruit except at 3 DAT. The specific activity of SOD declined at 2 DAT, which showed compromised SOD defense against superoxide radicals (O·−). APOD activity declined sharply at 3 DAT. Interestingly, GR activity was 1.9-fold higher in CMNP-treated fruit at 3 DAT. Higher GR and low APOD activity reflects limited functioning of the APOD/GR cycle (e.g., APOD and GR) in scavenging of H2O2 at 3 DAT. Guaiacol POD activity transiently increased at 1 DAT and then declined. POD plays an important role in cell wall lignification and indole acetic acid (IAA) oxidation. The decline in POD activity may cause a decrease in lignification while higher activity made the AZ sensitive to ethylene and thus promote abscission in citrus fruit. This work also showed that CMNP-induced abscission is a collaborative effort of oxidative metabolism in flavedo tissue (FT) and AZ.

The Incorporation of [4-14C] δ-Aminolaevulic Acid into Urinary Porphyrins in Symptomatic Porphyria

1970 ◽  
Vol 39 (2) ◽  
pp. 159-168 ◽  
Author(s):  
P. Goldswain ◽  
E. Dowdle ◽  
Norma Spong ◽  
L. Eales
Keyword(s):  
Oral Dose ◽  
Control Subject ◽  
Single Oral Dose ◽  
Metabolic Pathways ◽  
Specific Activity ◽  
Specific Activities ◽  
Urinary Porphyrins

1. The specific activities of urinary uroporphyrin and coproporphyrin were measured as functions of time following the administration of a single oral dose of [4-14C] δ-aminolaevulic acid (ALA) to six patients with symptomatic porphyria and one control subject. 2. The peak specific activity of coproporphyrin preceded that of uroporphyrin in all subjects studied and exceeded that of uroporphyrin in the patients with symptomatic porphyria. 3. These results are interpreted as indicating the existence of two distinct metabolic pathways in the liver for the disposal of ALA, rather than as contradicting the generally accepted role of uroporphyrinogen as a precursor of coproporphyrinogen.

Detection of protein disulphide-isomerase in sheep pancreas fractions

1982 ◽  
Vol 2 (5) ◽  
pp. 343-349 ◽  
Author(s):  
David A. Hillson ◽  
Jacqueline Anderson
Keyword(s):  
Specific Activity ◽  
Protein Biosynthesis ◽  
Major Site ◽  
General Role ◽  
Protein Disulphide Isomerase ◽  
Isomerase Activity ◽  
Liver Homogenates ◽  
Specific Activities

Conclusions The use of diethylpyrocarbonate to inhibit endogenous ribonuclease in sheep pancreas allows the detection of protein-disulphide-isomerase activity in homogenates, at specific activities of up to 4 units/g. This is higher than the specific activity in sheep liver homogenates (about 2 units/g) or in homogenates of other sheep tissues (16). It is thus evident that high levels of protein-disulphide-isomerase activity are present in sheep pancreas. This is consistent both with the postulated general role of protein disulphide-isomerase in protein biosynthesis (10,11) and with the in vitro action of the enzyme on its conventional substrate scrambled ribonuclease, since pancreas is the major site of ribonuclease synthesis.

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.

scholarly journals Studies on the Role of the are a Gene in the Regulation of Nitrogen Catabolism in Aspergillus nidulans

1975 ◽  
Vol 28 (3) ◽  
pp. 301 ◽  
Author(s):  
MJ Hynes
Keyword(s):  
Nitrogen Source ◽  
Aspergillus Nidulans ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Selection Methods ◽  
Growth Responses ◽  
Dominance Relationships ◽  
Regulatory Circuits ◽  
Specific Activities

Mutants of Apergillus nidulanswith lesions in a gene, areA (formerly called amdT), have been isolated by a variety of different selection methods. The areA mutants show a range of pleiotropic growth responses to a number of compounds as sole nitrogen sources, but are normal in utilization of carbon sources. The levels of two amidase enzymes as well as urease have been investigated in the mutants and have been shown to be affected by this gene. Most of the areA mutants have much lower amidase-specific activities when grown in ammonium-containing medium, compared with mycelium incubated in medium la9king a nitrogen source. Some of the areA. mutants do not show derepression of urease upon relief of ammonium repression. The dominance relationships of areA alleles have been investigated in� heterozygous diploids, and these studies lend support to the proposal that areA codes for a positively acting regulatory product. One of the new areA alleles is partially dominant to areA + and areA102. This may be a result of negative complementation or indicate that areA has an additional negative reiuIatory function. Investigation.of various amdR; areA double mutants has led to the conclusion that amdR and areA participate in independent regulatory circuits in the control of acetamide utilizatiol1. Studies on an amdRc; areA.double mutant indicate that areA is involved in derepression of acetamidase upon relief of ammo.nium repression.

Role of auxins, polyamines and ethylene in root formation and growth in sweet orange

2011 ◽  
Vol 55 (2) ◽  
pp. 375-378 ◽  
Author(s):  
A. F. S. Mendes ◽  
L. C. Cidade ◽  
W. C. Otoni ◽  
W. S. Soares-Filho ◽  
M. G. C. Costa
Keyword(s):  
Root Formation ◽  
Sweet Orange

scholarly journals Regulation of lipogenic capacity in lactating rats

1982 ◽  
Vol 208 (3) ◽  
pp. 611-618 ◽  
Author(s):  
M R Grigor ◽  
A Geursen ◽  
M J Sneyd ◽  
S M Warren
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Malic Enzyme ◽  
Fatty Acid Synthase ◽  
Specific Activity ◽  
Mammary Glands ◽  
Lipogenic Enzymes ◽  
Pregnancy And Lactation ◽  
Specific Activities

1. The rate of mammary-gland lipogenesis measured in vivo from 3H2O was suppressed after decreasing the milk demand by decreasing the number of pups from ten to two or three, as well as by giving diets containing lipid [Grigor & Warren (1980) Biochem. J. 188, 61-65]. 2. The specific activities of the lipogenic enzymes fatty acid synthase, glucose 6-phosphate dehydrogenase and ‘malic’ enzyme increased between 6- and 10-fold in the mammary gland and between 2- and 3-fold in the livers during the first 10 days of lactation. The increases in specific activity coupled with the doubling of liver mass which occurred during pregnancy and lactation resulted in considerable differences in total liver activities when compared with virgin animals. 3. Although consumption of a diet containing 20% peanut oil suppressed the activities of the three lipogenic enzymes in the livers, only the ‘malic’ enzyme was affected in the mammary glands. 4. In contrast, decreased milk demand did not affect the specific activities of any of the liver enzymes, whereas it resulted in suppression of all three lipogenic enzymes of the mammary glands. There was no effect on either the cytoplasmic malate dehydrogenase or the lactate dehydrogenase of the mammary gland. 5. In all the experiments performed, the activity of the fatty acid synthase correlated with the amount of material precipitated by the rabbit antibody raised against rat fatty acid synthase.

HIF-1α in endurance training: suppression of oxidative metabolism

2007 ◽  
Vol 293 (5) ◽  
pp. R2059-R2069 ◽  
Author(s):  
Steven D. Mason ◽  
Helene Rundqvist ◽  
Ioanna Papandreou ◽  
Roger Duh ◽  
Wayne J. McNulty ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Oxidative Metabolism ◽  
Hypoxia Inducible Factor ◽  
Transcriptional Response ◽  
Oxidative Capacity ◽  
Pyruvate Dehydrogenase Kinase ◽  
Amp Activated Protein Kinase ◽  
Training Protocol

During endurance training, exercising skeletal muscle experiences severe and repetitive oxygen stress. The primary transcriptional response factor for acclimation to hypoxic stress is hypoxia-inducible factor-1α (HIF-1α), which upregulates glycolysis and angiogenesis in response to low levels of tissue oxygenation. To examine the role of HIF-1α in endurance training, we have created mice specifically lacking skeletal muscle HIF-1α and subjected them to an endurance training protocol. We found that only wild-type mice improve their oxidative capacity, as measured by the respiratory exchange ratio; surprisingly, we found that HIF-1α null mice have already upregulated this parameter without training. Furthermore, untrained HIF-1α null mice have an increased capillary to fiber ratio and elevated oxidative enzyme activities. These changes correlate with constitutively activated AMP-activated protein kinase in the HIF-1α null muscles. Additionally, HIF-1α null muscles have decreased expression of pyruvate dehydrogenase kinase I, a HIF-1α target that inhibits oxidative metabolism. These data demonstrate that removal of HIF-1α causes an adaptive response in skeletal muscle akin to endurance training and provides evidence for the suppression of mitochondrial biogenesis by HIF-1α in normal tissue.

scholarly journals Partial purification of presynaptic plasma membrane by immunoadsorption.

1982 ◽  
Vol 94 (1) ◽  
pp. 88-96 ◽  
Author(s):  
G P Miljanich ◽  
A R Brasier ◽  
R B Kelly
Keyword(s):  
Plasma Membrane ◽  
Synaptic Vesicle ◽  
Nerve Terminal ◽  
Specific Activity ◽  
Electric Organ ◽  
Partial Purification ◽  
Vesicle Membrane ◽  
Specific Activities ◽  
Active Zones ◽  
Presynaptic Plasma Membrane

During transmitter release, synaptic vesicle membrane is specifically inserted into the nerve terminal plasma membrane only at specialized sites or "active zones." In an attempt to obtain a membrane fraction enriched in active zones, we have utilized the electric organ of the marine ray. From this organ, a fraction enriched in nerve terminals (synaptosomes) was prepared by conventional means. These synaptosomes were bound to microscopic beads by an antiserum to purified electric organ synaptic vesicles (anti-SV). The success of this immunoadsorption procedure was demonstrated by increased specific activities of bead-bound nerve terminal cytoplasmic markers and decreased specific activities of markers for contaminating membranes. To obtain a presynaptic plasma membrane (PSPM) fraction, we lysed the bead-bound synaptosomes by hypoosmotic shock and sonication, resulting in complete release of cytoplasmic markers. When the synaptosomal fraction was surface-labeled with iodine before immunoadsorption, 10% of this label remained bead-bound after lysis, compared with 2% of the total protein, indicating an approximately fivefold enrichment of bead-bound plasma membrane. Concomitantly, the specific activity of bead-bound anti-SV increased approximately 30-fold, indicating an enrichment of plasma membrane which contained inserted synaptic vesicle components. This PSPM preparation is not simply synaptic vesicle membrane since two-dimensional electrophoresis revealed that the polypeptides of the surface-iodinated PSPM preparation include both vesicle and numerous nonvesicle components. Secondly, antiserum to the PSPM fraction is markedly different from anti-SV and binds to external, nonvesicle, nerve terminal components.

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