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R Yamamoto

Publications and source records attributed to R Yamamoto.

18 recordsLinked to original sources
PubMed1979

Hydrophobic-ionic chromatography. Its application to purification of porcine pancreas enzymes.

1. All the porcine pancreas enzymes tested, regardless of their pI's were adsorbed on Amberlite CG-50 (a weakly acidic cation exchange resin) at pH 4, where the ion-exchange group (carboxyl group) is not dissociated. The adsorption is hardly influenced by ionic strength. 2. At pH 4, the adsorbed enzymes were partially eluted by organic solvents such as 50% propanol. 3. The adsorbed enzymes were effectively eluted by increasing the pH from 4 to 6. Trypsin (pI 10.5) was eluted before carboxypeptidase A (pI 4.5 AND 5.3) WITH 0.5 M acetate buffer, whereas the former enzyme was eluted after the latter enzyme with 0.2 M 3,3-dimethyl glutarate buffer. However, with either buffer, the elution order of enzymes was not always the same as the order of the pI's. 4. By a single Amberlite CG-50 column chromatography of porcine pancreas extracts, kallikrein, carboxypeptidase B, deoxyribonuclease, carboxypeptidase A, and trypsin were purified 100-fold, 16-fmately 13%. The purification procedures included treatment with protamine, ammonium sulfate fractionation, treatment with acid, DE-32 cellulose column chromatography, gel filtration on Sephadex G-100, preparative polyacrylamide gel electrophoresis, and affinity chromatography on 5' AMP-Sepharose 4B. The last procedure, affinity chromatography on 5' AMP-Sepharose 4B, was useful for the removal of other dehydrogenases. The enzyme which was homogeneous, as shown by polyacrylamide gel electrophoresis, had a molecular weight of about 92,000. The optimum pH was at 10.0 and isoelectric point at 5.2. The enzyme accepted both L-fucose and D-arabinose as substrate, but was specific for NAD+ as coenzyme. Km values were 0.15 mM, 1.4 mM, and 0.07 mM for L-fucose, D-arabinose, and NAD+, respectively. A single enzyme catalyzed the oxidation of L-fucose and D-arabinose, which had the same configurations of hydroxyl groups from C-2 to C-4. The reaction products obtained with L-fucose as substrate were L-fucono-lactone and L-fuconic acid. The L-fucono-lactone was an immediate product of oxidation and was hydrolyzed to L-fuconic acid spontaneously. This reaction was irreversible. Therefore, it is likely that L-fucose dehydrogenase is involved in the initial step of the catabolic pathway of L-fucose in rabbit liver.

Amylases↗
PubMed1978

Hormonal effects on the biosynthesis of sulfated glycoprotein in a microsomal fraction of the endometrium of rabbit uterus.

A crude microsomal fraction (M-Fr) was separated from the endometrial scrapings of uteri of ovariectomized rabbits with or without hormonal treatment. The effects of estrogen and progesterone on the incorporation into M-Fr of L-[U-14C]-fucose and N-acetyl-D-[6-3H]-glucosamine from their nucleotides were investigated. Estrogen increased the incorporation of these sugars, whereas progesterone suppressed this effect. The results of fractionation on a DEAE-Sephadex A-25 (Cl- form) column of the isotope-labelled complex saccharide mixtures, obtained by pronase digestion of the incubation mixtures, indicated that biosynthesis of sulfated glycoprotein was most sensitive to the hormones among the complex saccharides in M-Fr. Thus, a hormonal effects on the biosynthesis of sulfated glycoprotein in the endometrium of ovariectomized rabbit has been unambiguously confirmed at the microsomal level.

Acetylglucosamine↗
PubMed1977

Antibodies against human lymphokines: I. Methods for induction of antibodies capable of neutralizing stable (alpha) and unstable (beta) lymphotoxins released in vitro by activated human lymphocytes.

Various methods were employed to induce antibodies in rabbits that were capable of neutralizing different families of lymphotoxins (LT). Both stable (alpha-LT) and unstable (beta-LT) molecules, released by activated human lymphocytes in vitro, were neutralized. The different LT families were first separated into their respective groups by physical-chemical methods. Immunization with small quantities of antigen yielded a high percentage of responder animals. Techniques were developed for eliciting alpha-LT antibodies using as little as 2--3 ml of a cell-free supernatant. The situation was more difficult, however, when the unstable beta-LT molecules were employed as antigens. We found that because of the low concentration and lability of beta-LT in supernatants, the immunizing dose had to be: a) handled rapidly, b) larger than that used with the alpha-LT, and c) injected at closer intervals and over a longer immunization protocol. Physical-chemical studies supperted the concept that the LT-neutralizing activity in the immune serum was immunoglobulin.

Animals↗
PubMedDate not supplied

Efficacy of Linco-Spectin medication on mycoplasma meleagridis airsacculitis in turkey poults.

The efficacy of Linco-Spectin (LS) water medication was determined against Mycoplasma meleagridis (MM) airsacculitis in turkey poults under controlled conditions. The poults were obtained from commercial flocks naturally infected with MM. Water medication was given for the first five days of life. In Georgia and Ohio, LS was given at 0, 1, 2, and 4 g per gallon of drinking water. In California and Minnesota, LS was administered at 0 and 2 g per gallon of drinking water. At three weeks old, the birds were weighed individually and examined serologically, culturally, and grossly for MM airsacculitis. LS at 2 g activity per gallon of drinking water was beneficial in controlling MM airsacculitis in all four trials.

Administration, Oral↗
PubMedDate not supplied

Immune-complex involvement in the pathogenesis of infectious bursal disease virus in chickens.

Frozen kidney sections from chickens inoculated with infectious bursal disease virus (IBDV) were stained with fluorescein-conjugated rabbit anti-chicken gamma-globulin. Fluorescence was observed in the renal glomeruli of infected chickens, indicating that gamma-globulins, probably in the form of immune complexes, had lodged in the glomeruli of IBDV-infected chickens. This suggests that immune complexes may play an important role in the pathogenesis of IBDV infections in chickens.

Animals↗
PubMedDate not supplied

An infectious bursal disease virus outbreak in 14- and 15-week-old chickens.

Infectious bursal disease virus (IBDV) observed in a flock of 14- and 15-week-old chickens was typical of the acute symptomatic IBDV infections more common in younger birds. High flock morbidity was indicated by a marked decrease in feed consumption, although deaths were not excessive. At necropsy, affected birds had small hemorrhages in thigh muscles, creamy-yellow-colored bursae of Fabricius with prominent longitudinal striations, and swollen mottled kidneys. Histopathologic examination revealed bursal lesions typical of IBDV infection. One of six sera from necropsied birds was positive for antibody to IBDV in the agar-gel precipitin (AGP) test, and one week later all 35 samples tested were positive. Bursae were homogenized and found to contain IBDV as evidenced by precipitation, with antibody to IBDV, in the AGP test.

Age Factors↗