Purification and characterization of NAD and NADP-linked alpha-ketoaldehyde dehydrogenases involved in catalyzing the oxidation of methylglyoxal to pyruvate

Two alpha-ketoaldehyde dehydrogenases, one catalyzing the oxidation of methylglyoxal to pyruvate with NAD and the other with NADP, were isolated from goat liver and happened to be co-purified. Both the enzymes had been extensively purified to the point where only these two enzymes were present. By affinity chromatography on a thiol-Sepharose column, the two enzymes were separated. Molecular weight of both the enzymes was found to be 42,000 by gel filtration in a Sephadex G-200 column. Electrophoresis on sodium dodecyl sulfate-polyacrylamide gel revealed that the enzymes are composed of single subunits. Interaction with mercurials indicated the presence of SH group(s) in the active site of the NAD-linked enzyme only.

On the interaction of nucleotides and glycolytic intermediates with NAD-linked alpha-ketoaldehyde dehydrogenase

The effect of different nucleotides and glycolytic intermediates was tested on the NAD-linked and NADP-linked alpha-ketoaldehyde dehydrogenases involved in the oxidation of methylglyoxal to pyruvate. ATP, GTP, and ADP strongly inhibit the NAD-linked enzyme whereas activity of the NADP-linked enzyme remained unaltered. NADP at a concentration much below its catalytic concentration strongly inhibited the NAD-linked enzyme. This NADP inhibition decreased with decreasing of the pH of the incubation medium. Fructose 1,6-bisphosphate stimulated and glyceraldehyde 3-phosphate inhibited the activity of the NAD-linked enzyme whereas dihydroxyacetone phosphate inhibited NADP-linked activity. The stimulatory effect of fructose 1,6-bisphosphate diminished with lowering of the pH value. The various effects by several key metabolites of the glycolytic pathway indicate a possible physiological role for these enzymes.

Maximum likelihood methods in vowel recognition: a comparative study

Vowel classification accuracy is studied using a generalized maximum likelihood ratio method. It is shown that two simplifying assumptions can reduce computation times by as much as a factor of five while producing practically no change in recognition accuracy. The two simplifying assumptions remove cross correlation terms and produce an Euclidean distance discriminant function. The vowels are taken from 350 multisyllabic isolated words spoken by five male speakers. The vowels occur in a variety of preand postconsonantal contexts. The recognition scores obtained for vowels are 83 percent. The effect of grouping of similar vowels on recognition scores is found to be marginal. The high back and high front vowels show better recognition scores (92-94 percent). In general, recognition performance for individual vowels follows a definite trend with respect to. the vowel diagram. A reasonable similarity is observed between confusion matrix and the distribution of vowels in first and second formant frequency (F1 F2) plane.

The effect of a purified guar degrading enzyme on chick growth

Guar gum, a galactomannan, is growth depressing when fed to chicks. As part of the continuing studies on the mode of action of this and other gums in the intestine, a mannanase has been isolated which degrades guar gum. A commercial hemicellulase was separated into several protein fractions by chromatography on DEAE-cellulose. Only one of these proteins effectively reduced the viscosity of a guar gum solution. Activity towards pectin, rye water extract, and barley water extract was not present in the fraction which degraded guar gum but was found in other fractions at lower concentrations. Graded levels of this purified guar-degrading enzyme were incorporated into chick diets having 2% guar gum. This purified enzyme was effective at levels as low as .6 mg protein/kg diet in preventing growth depression caused by the guar gum and thus permitting growth equivalent to controls. Purity of this mannanase was confirmed by chromatography on QAE-Sephadex at pH 6.0 and by slab-gel electrophoresis at pH 8.4.

Mobilization of metabolites from leaves to grains as the cause of monocarpic senescence in rice

The pattern of senescence was studied by following the changes in chlorophyll and protein in the leaves and by measuring (32)P retention and export from source to sink during development of the rice plant (Oryza sativa L. cv. Jaya) subjected to different manipulative treatments. With the advance of reproductive development, the chronological sequence of leaf senescence was changed, so that the flag and the third leaf senesced earlier than did the second leaf. In presence of the daughter shoot of defruited plants, senescence was delayed in all three leaves of the mother plant, as compared to the same leaves of intact plants. Senescence of all three leaves was further delayed when both panicle and daughter shoots were removed from the plant. The above manipulative treatments caused the initial sequential pattern of senescence of leaves to persist. Removal of both panicle and daughter shoots caused little export of (32)P between leaves. In the presence of daughter shoots of defruited plants, export of (32)P was maximum from leaves of the mother plant to the nearest daughter shoots. This led to earlier senescence of such mother plant leaves than that of plants from which both panicle and daughter shoots were removed. The pattern of senescence and export of (32)P in the flag and the second leaf of the daughter shoot was essentially the same as that of the intact plant. Based on these findings, it was concluded that mobilization of metabolites from source to sink is the primary cause of monocarpic senescence in rice.

Isolation of methylglyoxal synthase from goat liver

An enzyme fraction which specifically catalyzes the formation of methylglyoxal from dihydroxyacetone phosphate has been isolated and partially purified from goat liver. The enzyme fraction appears to be substantially free from glyoxalase I, reduced glutathione, and triosephosphate isomerase. Approximately equimolar quantities of methylglyoxal and inorganic phosphate were obtained from dihydroxyacetone phosphate. Formation of methylglyoxal was confirmed by colorimetric and enzymatic estimations as well as by paper chromatography and its spectrum. Glyceraldehyde-3-phosphate, fructose 1,6-bisphosphate, dihydroxyacetone, and glyceraldehyde, failed to act as substrates. The enzyme is inhibited by some phosphorylated compounds and inorganic phosphates.

Performance of Down syndrome and other retarded children on the Cratty Gross-Motor Test

The Cratty Test of Gross-Motor Performance was administered to 18 Down syndrome and 18 other mentally retarded children between the ages of 7 and 14 years. Subjects were individually matched on both MA and CA. Examination of their test profiles showed that the Down syndrome children had consistently lower scores that did the matched control children, but only two of the differences were significant. The findings, therefore, provide tentative support for the notion that Down syndrome children suffer a specific deficit in some areas of motor coordination. A number of criticisms of the internal consistency of the test were discussed in terms of their theoretical and practical implications.

Antibiotic cross-resistance patterns of ambodryl and promazine resistant mutants

The antihistaminic drug ambodryl (Am) and the tranquillizer promazine (Pr), which had previously shown significant antimicrobial activities, were used to select bacterial mutants representing different levels of resistance to their action. These Am and Pr mutants were found to have simultaneously developed cross-resistance to penicillin (Pe), streptomycin (Sm), chloramphenicol (Cm), tetracycline (Tc) and kanamycin (Km). Certain first-step Am mutants of sensitive wild-type bacteria which were also sensitive to these antibiotics developed resistance to Pe and Sm as well as to Pr and the antihistamine benadryl (Bn). The next-step mutant of Am resistance not only doubled its resistance to these antibiotics and chemotherapeutics, but broadened its resistance-spectrum to cover Tc and Cm. These observations on cross-resistances seem to be best explained on the basis of a reduction in cell-membrane permeability acting in a nonspecific manner. The role of such cross-resistance in accounting for an overall increase in the minimum inhibitory concentrations (MIC) of many drugs against several groups of bacteria is evaluated.

The disposition of cadmium and zinc in Pandalus montagui

Cadmium uptake rates in various tissues of Pandalus montagui exposed to sea water containing 37 micrograms Cd/L for 14 days ranged from 0.002-0.06 microgram/dry tissue/hr. During depuration for 57 days, the levels in most tissues decreased slightly, but continued to rise in the hepatopancreas indicating Cd redistribution. Exposure to 65 micrograms Zn/L produced no substantial change in Zn content of the tissues. An increase occurred in eggs and hepatopancreas during the first six days of depuration. During exposure to Cd and Zn combined (40 micrograms Cd/L + 70 micrograms Zn/L), tissue Zn levels responded as with Zn alone. In the presence of Zn, Cd concentration was doubled in the hepatopancreas, depressed by one-third in the carcass, and did not change in the other tissues. Increased amounts of Zn (up to 410 micrograms Zn/L) had not effect on the Cd levels of the tissues except that the Cd level in the hepatopancreas was depressed, although the level was still greater than in the case of exposure to Cd alone. The possible role of metallothionein is discussed.

Accumulation of cadmium by Nereis virens

Cadmium concentration in Nereis virens exposed to sediment spiked with cadmium increased linearly with time, no equilibrium concentration being indicated by 24 days of exposure. The concentration with N. virens also increased with concentration of Cd in the sediment, and smaller worms accumulated higher amounts per unit weight than larger worms. With exposure to sediment containing 1 to 4 ppm Cd, accumulation rates ranged from 0.018 to 0.037 microgram Cd/g dry wt/hr for 1- to 2-g worms and from 0.014 to 0.024 microgram Cd/g dry wt/hr for 5- to 7-g worms. N. virens exposed to 0.03 to 9.2 ppm Cd in sea water for 14 days had accumulation rates of 0.019 to 2.217 microgram Cd/g dry wt/hr for 1- to 2-g worms and 0.013 to 1.327 microgram Cd/g dry wt/hr for 5- to 7-g worms. There was practically no excretion of cadmium for N. virens with initial concentrations of 5 to 20 microgram Cd/g dry wt during 75 days in clean conditions. Sediment containing 1 and 4 ppm Cd produced concentrations of about 0.03- and 0.1-ppm cd in the overlying water. The accumulation rates from sediment with 1 and 4 ppm Cd are equal to the rates from sea water with 0.03 and 0.1 ppm Cd, respectively, indicating that cadmium uptake by N. virens is primarily from the aqueous phase.

Albumin-bound bilirubin in subchoroidal fluid

The most unique property of subchoroidal fluid was found to be the high bilirubin level. One distinct yellow band in the same position as albumin was observed when it was subjected to electrophoresis on agarose film. The yellow compound was very soluble in chloroform. Its identity to bilirubin was confirmed by its absorption maximum at 445 nm, and a positive reaction with Ehrlich's diazo reagent. Subretinal fluid and liquid vitreous often had a yellowish appearance after ocular hemorrhage. However, their bilirubin level was not elevated above that of serum. Our data indicated that the degradation of RBCs may be an important causative factor of persistant detachment.

Direct gas chromatographic analysis of cyclic N-nitrosamines

A rapid gas chromatographic technique has been developed for quantitative estimation of cyclic N-nitrosamines. Cumbersome clean-up procedures are unnecessary and quantitative estimation can be done by injecting hexane extract without further pretreatment. The detection limit for the procedures is ca. 0.5 ng.

Plasma cortisol in glaucoma

Plasma cortisol level and intraocular tension were determined diurnally in 40 normal and 40 glaucomatous patients at 8 AM and 8 PM. It was observed that (1) plasma cortisol level was higher in glaucomatous patients at both the periods; (2) the diurnal variation in plasma cortisol was parallel to diurnal variation in intraocular tension in both glaucomatous and normal persons; and (3) the diurnal variation in plasma cortisol level also was more marked in glaucomatous patients as compared to normal persons.

Antifertility agents. 12. Structure-activity relationship of 3,4-diphenylchromenes and -chromans

Synthesis and antiimplantation activity of variously substituted 2,2-dialkyl-3,4-diphenylchromenes and 3,4-cis- and trans-chromans derived from them are described. Pregnancy-inhibiting activity in rats was exhibited by a number of these compounds, which was particularly marked in the case of 3,4-trans-3-phenyl-4-p-(beta-pyrrolidinoethoxy)-phenyl-7-methoxychroman (32), the corresponding 2,2-dimethyl analog 34, and 3-phenyl-4-p-(beta-pyrrolidinoethoxy)phenyl-7-methoxychromene (26). The structure-activity relationship of these compounds is discussed.

Studies in antifertility agents. 11. Secosteroids. 5. Synthesis of 9,11-secoestradiol

9,11-Secoestradiol (9) and 11-hydroxy-9,11-secoestradiol (12) have been synthesized starting from 17-acetoxyestradiol 3-methyl ether (1) and found to possess significant antifertility activity in rats. 3-Methoxy-9,11-seco-9-oxo-17beta-acetoxyestra-1,3,5(10)-trien-11-oic acid (2), prepared by CrO3 oxidation of 1, on hydrogenolysis gave methyl 17beta-hydroxy-3-methoxy-9,11-secoestra-1,3,5(10)-triene-11-carboxylate (3). The 17-O-THP derivative of 3 was treated with LiAlH4 to give 17beta-(O-tetrahydropyranyl)-3-methoxy-11-hydroxy-9,11-secoestra-1,3,5(10)-triene (5). The 11-O-mesylate of 5 on LiAlH4 reduction followed by mild acid treatment and demethylation under alkaline conditions gave 9. LiAlH4 reduction of 3 gave 9,11-seco-11-hydroxyestradiol 3-methyl ether (11) which on demethylation gave 9,11-seco-11-hydroxyestradiol (12).

Nuphar Alkaloids: 3-Epinupharamine

The structure of a new alkaloid isolated from Nuphar variegatum is shown to be that of 3-epinupharamine (4).