Selective inhibition of MAO-A in serotonergic synaptosomes by two amphetamine metabolites, p-hydroxyamphetamine and p-hydroxynorephedrine

The present study was carried out mainly to clarify whether the two amphetamine metabolites, p-hydroxyamphetamine (P-OHA) and p-hydroxynorephedrine (p-OHN) are taken up by mouse brain 5-hydroxytryptamine (5-HT) nerve terminals to inhibit type A monoamine oxidase (MAO-A) and then potentiate the abnormal behavior, head-twitch. Of the two metabolites, only intracerebroventricular p-OHA, at 80 μg/mouse, sufficient to cause a head-twitch response (HTR), appreciably inhibited MAO-A activity without affecting MAO-B activity in homogenates of the mouse striatum, hypothalamus and the rest of the forebrain; and p-OHN did not inhibit either type of MAO at the dose tested. Estimation of intra- and extrasynaptosomal MAO-A activity showed that both metabolites significantly inhibited only the intrasynaptosomal deamination of 5-HT by MAO-A with p-OHA being more potent. Taken together with our previous findings, these present results clearly indicate that p-OHA may accumulate in the 5-HT nerve terminals through the uptake system, and concomitantly inhibit MAO-A activity. These actions of p-OHA may increase intraneuronal 5-HT levels and then potentiate 5-HT release to cause interaction with the post-synaptic 5-HT receptors.     

Resuscitation of Vibrio cholerae O1 strain TSI-4 from a viable but nonculturable state by heat shock

Abstract Vibrio cholerae strain TSI-4 was incubated in an M9 salt solution at 15 °C for more than 100 days. The plate counts showed no viable cells on day 30, but a broth culture from that day showed the growth of bacteria. However, after 35 days the bacteria entered the nonculturable state, based on the assessment of both the plate counts and broth culture. A portion of the culture was heated at 45 °C for 1 min in a water bath and subsequently plated onto a nutrient agar plate. More than 1000 colonies were recovered after this heat-shock treatment. The recovered cells showed the same chromosomal DNA pattern in the restriction map and the same outer membrane protein pattern in SDS-PAGE. Recovery of viable cells by heat-shock was achieved in cultures grown on M9 salt but not from cultures grown in phosphate-buffered saline. This suggests that the presence of NH₄Cl in the M9 salt solution may support the growth of the bacteria in a low nutrient medium, while also playing an important role in resuscitation.     

Transformation of cucumber (Cucumis sativus L.) plants using Agrobacterium tumefaciens and regeneration from hypocotyl explants

Summary Transgenic cucumber (Cucumis sativus L.) plants were successfully obtained from hypocotyl explants inoculated with Agrobacterium tumefaciens, which harbored a binary vector plasmid with NOS-nptII, CaMV 35S-I-gus and CaMV 35S-hph genes. Acetosyringone enhanced the efficiency of transformation at the cut surface cells of hypocotyl explants during five days of co-cultivation. Transformed cells were more effectively selected using 20–30 mg/l hygromycin B than using 50–100 mg/l kanamycin. Shoot regeneration occurred within 4–6 wks, and 12 of 21 regenerated plantlets displayed strong GUS expression in the very young leaves. All of 8 GUS-positive R0 plants examined showed single or a few positive bands by Southern blot analysis. The expression of the CaMV 35S-I-gus gene was observed in various tissues and organs of R0 and R1 transgenic cucumber plants.     

Organic-Solvent-Tolerant Bacterium Which Secretes Organic-Solvent-Stable Lipolytic Enzyme

A bacterial strain which could be grown in a medium containing organic solvents and which could secrete lipolytic enzyme was isolated. The stability of the lipolytic activity of the supernatant of the culture increased significantly in the presence of organic solvents such as toluene, cyclohexane, ethanol, and acetone.     

Modulation of the Activity of Purified Tonoplast H+-ATPase from Mung Bean (Vigna radiata L.) Hypocotyls by Various Lipids

H⁺-ATPase was solubilized from the tonoplast of mung bean (Vignaradiata L.) hypocotyls and purified by fast protein liquid chromatographyon a Mono Q ion-exchange column. The purified ATPase hardlycontained any phospholipid, but it did contain 10 to 15 moleculesof sterol and 25 to 30 molecules of glycolipid per ATPase molecule,and it had little activity without exogenously added phospholipids.Each individual polar head group, acylglyceride and fatty acidthat constituted a phospholipid was incapable by itself of activatingthe ATPase. Sterols and cerebroside had little activating effect.Maximal activation of ATPase was noted with asolectin or variousmolecular species of phosphatidylcholine (PC) at 0.005% to 0.01%(w/v). The activation by the various molecular species of PCwas dependent on the length and degree of unsaturation of fattyacyl chains. PC with two saturated and long fatty acyl chainsof more than 18 carbon atoms failed entirely to activate theATPase. PC, PS and PG with 1-palmitoyl (16:0)-2-oleoyl(18:1)fatty acyl chains all activated ATPase to nearly the same extentas asolectin, but the activation by PE and PA with the samefatty acyl composition was 52% and 15% of that by asolectin,respectively. The molecular species of PC with phase-transitiontemperatures below 50C activated ATPase, as determined at 38C.The dependence on temperature of the activation by the molecularspecies of PC indicated that the activation of the ATPase beganclose to the temperature of the phase transition of the PC added.These data indicate that phospholipids in the liquid-crystallinephase are essential for the catalytic activity of the ATPase. (Received June 4, 1992; Accepted January 18, 1993)     

Hepatocellular carcinoma associated with chronic Schistosoma mansoni infection in a chimpanzee

Hepatocellular carcinoma associated with chronic Schistosoma mansoni infection in a chimpanzee, estimated to be a 12-year-old and born in West Africa, is reported. The hepatic tumor appeared as a solitary firm nodule, and histological examination revealed well-differentiated hepatocellular carcinoma with a trabecular pattern. Hepatitis B virus and hepatitis C virus infections were excluded by serological testing in that animal. This is the first report of hepatocellular carcinoma in the chimpanzee with schistosomiasis.     

Identification of genes expressed in the shoot apex ofBrassica campestris during floral transition

The vegetative-to-floral transition ofBrassica campestris cv. Osome was induced by vernalization. Poly(A)+RNA was isolated from the transition shoot apex after 6 weeks of vernalization, the floral apex after 12 weeks of vernalization and the expanded leaves just before vernalization, and cDNAs were synthesized. These cDNAs were used for subtraction and differential screening to select cDNA preferentially present in the transition and floral apices. Nucleotide sequences of the resulting 14 cDNA clones were determined, and northern blot analysis was carried out on six cDNAs. Two cDNA clones which did not show significant similarity to known genes were shown to be preferentially expressed in the floral apex.     

Pulse sequences generated by a degenerate analog neuron model

The response characteristics of an electronic neuron model proposed by the authors are investigated. Periodic stimulating pulse sequences with a fixed frequency are applied to the analog neuron model and the response pulse sequences are studied. In the degenerate case, the state transition of the neuron model during one period of the stimulating pulse sequence is described by a first order piecewise linear difference equation with a jump. It is shown that the periodic response pulse sequences of the neuron model belong to a special class of pulse sequences generated by a simple algorithm, and that the relation between the pulse width (or amplitude) of the stimulating pulse and the firing rate of the neuron model takes the form of an extended Cantor function.     

Preparation of Uridine Diphosphate-N-Acetylgalactosamine from Uridine Diphosphate-N-Acetylglucosamine by Using Microbial Enzymes

A method was developed for the large scale preparation of uridine diphosphate-N-acetylgalactosamine (UDP-GalNAc) from uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) by means of microbial enzymes. With Bacillus subtilis cell-free extract as a source of UDP-GlcNAc 4-epimerase, about 35% of the UDP-GlcNAc added was converted to UDP-GalNAc. After the residual UDP-GlcNAc was degraded to uridine triphosphate and N-acetylglucosamine-1-phosphate with a protamine-treated extract of bakers' yeast as a source of UDP-GlcNAc pyrophosphorylase, UDP-GalNAc was separated by anion-exchange column chromatography. The nucleotide was recovered by adsorption on charcoal and elution with ammoniacal ethanol. The final yield was about 100 μmol.