scholarly journals Studies on the biosynthesis of quinones in fungi. Incorporation of 6-methylsalicylic acid into fumigatin and related compounds in Aspergillus fumigatus I.M.I. 89353

1965 ◽  
Vol 97 (2) ◽  
pp. 321-332 ◽  
Author(s):  
NM Packter
Keyword(s):  
Aspergillus Fumigatus ◽  
Specific Activity ◽  
High Specific Activity ◽  
The Other ◽  
Inhibitory Effects ◽  
Orsellinic Acid ◽  
Aromatic Components ◽  
Related Compounds

1. Orsellinic acid has been detected as a metabolite of Aspergillus fumigatus. 2. The other principal aromatic components of the medium are fumigatin and the quinol, fumigatol. Fumigatol has been shown to be dihydrofumigatin after oxidation to the quinone followed by acetylation. 3. (14)C-labelled 6-methylsalicylic acid can be hydroxylated in A. fumigatus to form orsellinic acid and decarboxylated to give m-cresol. 4. (14)C-labelled 6-methylsalicylic acid is incorporated into fumigatin and fumigatol (1.0-1.5%), but the conversion does not occur until about 2-3 days after supplementation of the medium. At this stage of growth, the organism has already synthesized approx. 20 times as much fumigatol as fumigatin and this ratio is reflected in the much lower specific activity of the quinol. 5. Supplementation of the medium with either orsellinic acid or orcinol, in addition to (14)C-labelled 6-methylsalicylic acid, greatly decreases the latter's incorporation into fumigatin. At the same time, the cultures containing these substances are stimulated to produce another quinone with relatively high specific activity. 6. 6-Methylsalicylic acid has not been detected in the medium of normal cultures. The results indicate that 6-methylsalicylic acid itself is not a direct precursor of fumigatin and fumigatol but that it is converted into a true intermediate, probably after hydroxylation to orsellinic acid. 7. Supplementation of the medium with 6-methylsalicylic acid (15-25mg./200ml.) greatly affects the metabolism of A. fumigatus. Growth is inhibited and the synthesis of fumigatol is markedly depressed in these cultures. The inhibitory effects may possibly be related in some way to the production of m-cresol.

scholarly journals Luminescent detection method for immunodot, Western, and Southern blots.

1986 ◽  
Vol 34 (12) ◽  
pp. 1645-1650 ◽  
Author(s):  
M M Leong ◽  
C Milstein ◽  
R Pannell
Keyword(s):  
Monoclonal Antibody ◽  
Cell Line ◽  
Indirect Method ◽  
Detection Method ◽  
Specific Activity ◽  
High Specific Activity ◽  
The Other ◽  
X Ray ◽  
Bispecific Monoclonal Antibody ◽  
Direct Binding

An anti-peroxidase-anti-biotin hybrid hybridoma rat cell line, capable of producing a bispecific monoclonal antibody, has been derived to explore its use in conjunction with a luminol immunodetection system. Luminescence was detected using x-ray film. The method was sufficiently sensitive and effective, but was less sensitive than autoradiographic methods using high-specific-activity 32P-labeled probes. Exposure times, on the other hand, were of the order of seconds rather than days. The direct binding of both peroxidase and biotin by the bispecific monoclonal antibody is simpler but less sensitive than the more conventional indirect method using a commercial peroxidase coupled with anti-rat antibody as a developing antibody.

In vivo preparation of [32P]cAMP and thin-layer chromatography of cAMP-related compounds

1979 ◽  
Vol 57 (11) ◽  
pp. 1281-1283
Author(s):  
Hiroshi Yamazaki ◽  
Kwok-Luen Leung ◽  
Ann D. E. Feaser
Keyword(s):  
Wild Type Strain ◽  
Radiochemical Purity ◽  
Specific Activity ◽  
High Specific Activity ◽  
Alumina Column ◽  
Alumina Column Chromatography ◽  
Camp Metabolism ◽  
Layer Chromatography ◽  
Related Compounds

A simple and rapid method for preparing [32P]adenosine 3′,5′-cyclic monophosphate (cAMP) is described. A culture of an Escherichia coli mutant which excretes cAMP about 150 times faster than does a wild-type strain was incubated overnight with [82P]orthophosphate of high specific activity (e.g., 4000 Ci/mol (1 Ci = 37 GBq)). The [32P]cAMP which accumulated extracellularly was then purified to 99.9% radiochemical purity in less than 4 h by adsorption to charcoal and alumina column chromatography. A two-dimensional chromatography system using a PEI-cellulose plate is also described which should prove useful for studying cAMP metabolism with 32P- or 3H-labeled cAMP or ATP.

SKELETAL SILVER CATALYSTS FOR THE OXIDATION OF ETHYLENE TO ETHYLENE OXIDE

1956 ◽  
Vol 34 (5) ◽  
pp. 665-671 ◽  
Author(s):  
A. Cambron ◽  
W. A. Alexander
Keyword(s):  
Ethylene Oxide ◽  
Alkaline Earth ◽  
Specific Activity ◽  
High Specific Activity ◽  
Alkaline Earth Metals ◽  
The Other ◽  
Silver Alloys ◽  
Silver Catalysts

Skeletal silver catalysts of high specific activity have been prepared by the removal of calcium from calcium–silver alloys. The activity of these catalysts in the oxidation of ethylene to ethylene oxide has been investigated. Catalysts prepared by the removal of the other alkaline earth metals from their alloys with silver have also been studied. It has been found that catalysts prepared from calcium–silver alloys show a higher specific activity and are more stable and more conveniently prepared than the catalysts from the other silver alloys investigated.

Thionamides and arsenite inhibit specific T3 binding to the hepatic nuclear receptor

1990 ◽  
Vol 68 (3) ◽  
pp. 616-621 ◽  
Author(s):  
Shinko Takagi ◽  
Brian C. W. Hummel ◽  
Paul G. Walfish
Keyword(s):  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Specific Activity ◽  
Binding Capacity ◽  
High Specific Activity ◽  
Relative Mass ◽  
Affinity Constant ◽  
Scatchard Analysis ◽  
Therapeutic Effects ◽  
Inhibitory Effects

Methimazole (MMI) and propylthiouracil (PTU) are widely used for the treatment of Graves' disease. However, no studies have been reported on the action of these drugs on binding of L-triiodothyronine (T3) to the nuclear receptor. T3 receptors of rat liver nuclei, prepared by differential centrifugation, were extracted with 0.4 M KCl and 5 mM dithiothreitol (DTT). In the assessment of T3 binding to the DTT-reduced receptor, the hepatic nuclear extract was chromatographed on Superose 6 to remove DTT and isolate proteins of relative mass ≈ 50 000 (chromatographed nuclear receptors (CNRs)), prior to the addition of [125I]T3 of high specific activity (3300 μCi/μg; 1 Ci = 37 GBq). MMI or PTU at 2 mM reduced specific T3 binding to CNR by 84% and 85%, respectively. The inhibitory effects of these reagents and 2 mM sodium arsenite (which complexes dithiols) were additive. Scatchard analyses indicated that neither MMI nor PTU (at 2 mM) significantly altered the affinity constant (Ka) (from 2.41 × 109 to 1.74 × 109 M−1 for PTU and 1.79 × 109 M−1 for MMI), while they both decreased (p < 0.02) maximal binding capacity (from 0.36 ± 0.02 to 0.19 ± 0.02 pmol/mg protein for MMI and 0.17 ± 0.02 pmol/mg protein for PTU). Dose-response curves showed that 50% inhibition was attained at 0.6 mM PTU or 1.0 mM MMI with ≈25% inhibition by both at 0.1 mM. Artefactual binding effects by MMI and PTU on [125I]T3 were excluded by chromatography experiments. Similar results were obtained using nuclear receptors prepared from livers of hyperthyroid rats. Pretreatment of CNR for 1 h with 5 mM methyl methanethiosulfonate (an oxidant of thiol groups) abolished the inhibitory effects of PTU, MMI, or arsenite, but was not inhibitory in itself. From these studies it is concluded that (i) MMI and PTU could exert at least part of their therapeutic effects by inhibiting specific binding of L-T3 to its hepatic nuclear receptor; (ii) these inhibitory effects of MMI and PTU are likely due to an interaction with cysteine residues (some of which are not in a dithiol configuration) that are essential for T3 binding to its receptor; and (iii) binding of T3 is not inhibited by oxidation of receptor thiols to methyl dithiol groups.Key words: nuclear triiodothyronine (T3) receptor, methimazole, propylthiouracil, Scatchard analysis.

Fragment D Immunoreactivity: The Influence of Iodination and Calcium Environment

1979 ◽  
Author(s):  
B. Kudryfc ◽  
N. Blombäck
Keyword(s):  
Conformational Changes ◽  
Specific Antibody ◽  
Binding Sites ◽  
Specific Activity ◽  
High Specific Activity ◽  
The Other ◽  
Antigenic Determinants ◽  
Affinity Binding ◽  
Compact Structure ◽  
Chloramine T

Human fragment D (Fg-Ds) has been iodinated using both the Chloramine-T and lactoperoxidase methods. The specific activity was similar regardless of the method used. However, binding to a specific antibody was different for each preparation. The antigen labeled by the Chloramine-T method bound to a maximum of 40%, the other labeled product bound up to 85%. A correlation between the degree of immunoreactivity and avidity for a fibrinmonomer conjugate was found also. Fibrinmonomer bound about twice the amount of lactoperoxidase iodinated Fg-Ds as it did the Chloramine-T product. The use of these conjugates in the purification of immunoreactive Fg-Ds of high specific activity will be discussed. affinity binding sites for calcium have recently been demonstrated in fibrinogen. The presence of bound calcium is also believed to protect Fg-Ds from further digestion by plasmin. This is probably due to the formation of a more compact structure. However, conformational changes for calcium bound fibrinogen or Fg-Ds have not been observed. We tested the immunoreactivity of the lactoperoxidase iodinated Fg-Ds in presence and absence of calcium. Differences were found and this data suggests that some modification of antigenic determinants takes place as a consequence of calcium in the environment.

Expression and Characterization of a Novel Lipase from Aspergillus fumigatus with High Specific Activity

2011 ◽  
Vol 165 (3-4) ◽  
pp. 949-962 ◽  
Author(s):  
Jiao-Jiao Shangguan ◽  
Yu-Qiang Liu ◽  
Fu-Jun Wang ◽  
Jian Zhao ◽  
Li-Qiang Fan ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Specific Activity ◽  
High Specific Activity

scholarly journals ANTIBODY PRODUCTION IN VITRO

1968 ◽  
Vol 127 (4) ◽  
pp. 661-674 ◽  
Author(s):  
Gilmour Harris
Keyword(s):  
Antibody Production ◽  
Small Proportion ◽  
Specific Activity ◽  
Specific Antigen ◽  
High Specific Activity ◽  
Inhibitory Effects ◽  
Spleen Cells ◽  
Dividing Cells ◽  
Stimulation Of

The effect of high specific activity thymidme-3H on proliferation and antibody production, using the hemolytic plaque-forming technique, by spleen cell suspensions in vitro from rabbits killed after a boost of SRC's has been studied. High specific activity thymidine-3H inhibited the proliferative ay well as the antibody response to antigen, and it was conduded that this was the result of the incorporation of radioactive 3H into the nuclei of dividing cells which were synthesizing antibody in these cultures. The stimulation of the rate of DNA synthesis by specific antigen could be correlated with the ability of antigen to maintain antibody production, as measured by the specific hemolytic plaque-forming technique, above levels found in control cultures, incubated without antigen. Radioautographic studies of PFC's in vitro showed that the majority of the cells arose from the DNA-synthesizing population of cells in these cultures, confirming the conclusions from the results of the inhibitory effects of high specific-activity thymidine-3H on PFC's. It was found that these PFC's, labeling with thymidine-14C, formed only a small proportion of all the cells labeled in this way in these cultures. The postulation was made that antigen, in vitro, provided a stimulation for cell proliferation in the responsive population of rabbit spleen cells, but that only a small proportion of this population could be induced by antigen to synthesize antibody.

scholarly journals STREPTOCOCCAL NUCLEASES

1967 ◽  
Vol 126 (3) ◽  
pp. 497-508 ◽  
Author(s):  
Lewis W. Wannamaker ◽  
Barbara Hayes ◽  
Walid Yasmineh
Keyword(s):  
Ribonucleic Acid ◽  
Specific Activity ◽  
High Specific Activity ◽  
The Other ◽  
Acid Inhibitor ◽  
Bacterial Rna ◽  
Zone Electrophoresis ◽  
Specific Activities ◽  
And Behavior ◽  
Deoxyribonuclease Activity

Preparations of streptococcal DNAse D with high specific activity and free of other streptococcal nucleases have been obtained by zone electrophoresis and column chromatography. Antisera prepared by injecting rabbits with such preparations specifically neutralize the activity of this enzyme. As with DNAse B, preparations of DNAse D regularly exhibit ribonuclease activity. For both B and D enzymes, the order of substrate preference is thymus DNA, yeast RNA, bacterial RNA; but the specific activity of the D enzyme is higher than that of the B enzyme with respect to thymus DNA and lower with respect to bacterial RNA. Both the deoxyribonuclease and the ribonuclease activities exhibited by preparations of both enzymes are inhibited by bacterial RNA, but approximately 100-fold greater concentrations of bacterial RNA are required to achieve inhibition of the deoxyribonuclease activity of the D enzyme equivalent to the inhibition of the B enzyme. The deoxyribonuclease activity of the D enzyme is also inhibited by yeast RNA, but even larger amounts are required. These observations indicate that the D enzyme is immunologically distinct from the other streptococcal nucleases and that it differs quantitatively from the B enzyme with respect to relative specific activities on different substrates and behavior in the presence of the bacterial ribonucleic acid inhibitor.

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

Autoprothrombin C Activity from Prothrombin with Snake Venom or Trypsin

1962 ◽  
Vol 08 (03) ◽  
pp. 425-433 ◽  
Author(s):  
Ewa Marciniak ◽  
Edmond R Cole ◽  
Walter H Seegers
Keyword(s):  
Snake Venom ◽  
Thrombolytic Agent ◽  
Sodium Citrate ◽  
Specific Activity ◽  
High Specific Activity ◽  
Citrate Solution ◽  
Clotting Factors ◽  
Activation Products ◽  
Russell’S Viper ◽  
Autoprothrombin C

SummarySuitable conditions were found for the generation of autoprothrombin C from purified prothrombin with the use of Russell’s viper venom or trypsin. DEAE chromatographed prothrombin is structurally altered and has never been found to yield autoprothrombin C and also did not yield it when Russell’s viper venom or trypsin were used. Autoprothrombin C is derived from prothrombin with tissue extract thromboplastin, but not in large amounts with the intrinsic clotting factors. With the latter thrombin and autoprothrombin III are the chief activation products. Autoprothrombin III concentrates were prepared from serum and upon activation with 25% sodium citrate solution or with Russell’s viper venom large amounts of autoprothrombin C were obtained, and this was of high specific activity. Theoretically trypsin is not a thrombolytic agent, but on the contrary should lead to intravascular clotting.

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