Isolation and reconstitution of two electron transfer components of tryptophan side chain oxidase.

The isolation and reconstitution of two electron transfer components of tryptophan side chain oxidase from Pseudomonas (ATCC 29574) are described. The dehydrogenase component abstracts electrons from the substrate and transfers them to oxidation-reduction dyes such as potassium ferricyanide and 2,6-dichlorophenolindophenol but not to molecular oxygen. It is composed of a single polypeptide chain with a molecular weight of 72,000 and exhibits the absorption spectrum of a reduced b-type cytochrome with maxima at 563, 532, 433, 323, and 278 nm. The oxidase component transfers electrons, derived from the former component, to oxygen, and has a molecular weight of 48,000. The absorption spectrum exhibits broad peaks at 680, 438, and 358 nm, and a peak at 280 nm. On sucrose gradient centrifugation and polyacrylamide gel electrophoresis, these two components are shown to form a molecular complex, which has the reconstituted oxidase activity. The turnover number of the reconstituted enzyme is comparable to that of the native enzyme.     

Histamine-releasing activity (HRA). I. Production by mitogen- or antigen-stimulated human mononuclear cells.

Supernatants from 1- to 2-day cultures of human mononuclear cells induced the release of histamine from basophils. Generation of this histamine-releasing activity (HRA) was stimulated by addition of concanavalin A to the cell cultures. Mononuclear cells were also cultured with SKSD and Candida albicans antigens. Stimulation of HRA production by these antigens was correlated with positive delayed skin reactions. Serial dilutions of supernatants assayed for HRA provided a semiquantitative determination of the level of HRA in mitogen- or antigen-stimulated samples. Antigen increased HRA production when added during the first or second day of culture. Generation of HRA probably requires active protein synthesis, since puromycin was inhibitory, and since preformed HRA could not be recovered from lysed cells. HRA was detected in supernatants after 4 hr, and the effects of antigen stimulation were apparent after 8 hr of culture. Replacement of supernatants with fresh culture medium allowed continued synthesis of substantial quantities of HRA during the second day of culture. A linear correlation was observed between the amount of HRA produced and the mononuclear cell concentration. Our findings provide evidence for the interaction of lymphocytes and basophils via a soluble mediator.     

DEVELOPMENT OF ACETYLCHOLINESTERASE MULTIPLE MOLECULAR FORMS IN CHICKEN MUSCLES

Abstract— AChE activity and protein content in chicken ALD and PLD muscles was studied during pre- and postnatal development. Protein content in both muscles increased whereas AChE activity increased in ALD and decreased in PLD during development. All studied values reached the steady-state 3 weeks after hatching.
Electrophoretic separation of the samples showed three molecular forms of AChE present in both adult ALD and PLD muscles. Two molecular forms in ALD muscle increased slowly, one form quickly. On the other hand, the activity of AChE forms in PLD muscle decreased with different rates. It appears from these results that the multiple molecular forms of AChE in muscles are not of the same physiological importance.     

A new type of semi-empirical molecular orbital method for large molecules.

A new type of molecular orbital method is proposed. It is applicable to large molecules containing large conjugated substructures. Only π-electrons in the conjugated part, but all-valence electrons in the non-conjugated part of a molecule, are taken into account explicitly. The Fock matrix elements are evaluated from the semi-empirical values employed in the existing all-valence-electron methods. The examples presented here suggest that the new type of MO method predicts electronic structures which are quite similar to those obtained by complete semi-empirical MO calculations. This new method may make it possible to reasonably well describe the electronic structure of, and interaction between, large molecules using considerably less computation time and core storage than the complete calculation analogs.     

1,4-Methylhistamine is a specific substrate for type B monoamine oxidase

1,4-Methylhistamine was characterized as substrate for monoamine oxidase (MAO) in rat liver mitochondria. The $\text{K}$_m and $\text{V}$_max values were 38.8 μM and 6.33 nmoles/mg protein/60 min, respectively. The inhibition experiments with clorgyline and deprenyl, the selective inhibitors for type A and type B MAO, showed that 1,4-methylhistamine was specific for type B MAO.     

Effect of boron on the pollen vitality and yield of rice plants (Oryza sativa L. var. Jaya)

Summary Rice plants were grown in sand cultures with nutrient solution including boron at 0, 1, 2.5 and 5 ppm concentrations.In general, supply of boron improved the pollen vitality of rice flowers. It was stimulating up to 2.5 ppm concentration in the nutrient solution, beyond which (i.e., at 5 ppm) inhibitory effects appeared. The availability of boron also increased the yield of rice grains in the same order.Stimulating effects of boron may be linked with greater availability of sugars, increased enzymatic activity and respiration which favoured better growth of pollen. Inhibitory effects of stronger concentration of boron (5 ppm) may be related with physiological depression and injury to protoplasm itself.     

Chemical relaxation studies on the horse liver alcohol dehydrogenase system.

Chemical relaxation studies on the system horse liver alcohol dehydrogenase, nicotinamide adenine dinucleotide, and ethanol were conducted observing fluorescence changes between 400 and 500 nm. Temperature-jump experiments were performed at pH 6.5, 7.0, 8.0, and 9.0; concentration-jump experiments at pH 9.0. The reciprocal of the slowest relaxation time was found to be linearly dependent upon the enzyme concentration for relatively low enzyme concentrations, as predicted earlier. Use of the wide pH-range necessitated expression of the four apparent dissociation constants of the catalytic reaction cycle in terms of pH-independent constants. The system was described in terms of only one (or two) catalysis-linked protons not associated with the electron transfer. Protonic steps in a buffered system are in rapid equilibrium, too fast to be measured with the equipment available. Assuming only two of the four bimolecular reaction steps in the four-step cycle are fast compared to the remaining two, six cases may be considered with six expressions for the reciprocal of the slowest relaxation time. Comparison with the experimental data revealed that the bimolecular reaction steps governing the slowest relaxation time change with pH. Above the effective time resolution of the temperature-lump instrument with fluorescence detection (0.1 msec) only one other relaxation time was detectable and only at pH 9. This relaxation time, found to be independent of the concentration of all reactants within experimental error (r = 10 +/- 5 msec), is most likely due to an interconversion among ternary complexes.     

Tropical ulcers.

We present 87 cases of chronic leg ulcers. The ages and sexes of the patients, and the symptomatology and complications, are described. The term "tropical ulcer" is inappropriate for these cases--though the term may be appropriate for certain rare acute ulcers colonized by Vincent's bacilli. For most persistent leg ulcers in the tropics, however, a general term of chronic ulcer is better--because it stimulates one to look for the cause and to treat the patient accordingly.     

The effect of S-adenosyl-L-methionine (SAM) on membrane permeability in the perfused rat liver

S-adenosilmethionine is present in most human tissues and is an important factor for transmethylation, transulphuration and aminopropylation reactions. The compound improves the biological, morphological and histochemical aspects of rat liver following CCl4 intossication. At the same time has been successfully used during chronic liver disease in man. With the aim to better clarify the action mechanism of SAMe some aspects concerning its effects on cell permeability in rat liver, by using the perfusion technique, have been investigated. In particular the capacity of this compound to prevent the enzymatic loss (GPT and GOT) during liver perfusion has been studied. 30 perfusions without SAMe, as control, and 6 by infusing 2 mg of compound during the perfusion time have been accomplished. Varing the perfusion time from 0 to 120 min it has been observed that at any time the presence of the SAMe reduced by about 50% the loss of GOT. Similarly the activity of GPT ranging from 2 to 6 mU/ml indicate that no appreciable enzyme output occurs in presence of SAMe.