Single-step,rapid separation of acidic and basic isoenzymes from commercial horseradish peroxidase

A simple and sensitive high-performance liquid chromatography method with electrochemical detector is described for the determination of free 3-methoxy-4-hydroxyphenylacetic acid (HVA) in human plasma. The method does not involve any extraction, is specific and reproducible, and has the potential to measure serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) simultaneously. The plasma concentration of free HVA in eight normal, healthy adult volunteers was 10.9 ± 4.6 (mean ± SD). In a preliminary study, in one schizophrenic patient the plasma HVA increased twofold after neuroleptic treatment.     

Dormancy in peach (Prunus persica L.) flower buds

Morphological studies were carried out with peach flower buds collected monthly in 1989 and 1990, from two months before leaf fall (7 March) until two to three weeks before bloom (7/8 August). Chilled (2–4°C for 30 days) and unchilled buds were exposed to 20 to 25°C, 100% RH and continuous light. Gibberellin A₃ (3 ng or 30 ng) was applied to some of the non-chilled cuttings at three days intervals. Then, 12, 19, and 26 days after they were planted, the buds were sampled and processed for histological studies. Cultured flower buds (chilled or unchilled) had accelerated anther and gynoecium morphogenesis after 12 days under controlled conditions, compared to buds processed immediately after collection from the field. Chilling treatment augmented the bud culture effect, while Gibberellin A₃ applications to the excised buds retarded bud morphogenesis to a stage comparable to that of buds collected directly from the field. This, suggests that the comparatively high levels of Gibberellin A_1/3 we previously found in mid winter [15, 18] could be at least one of the factors that controls floral bud dormancy by retarding anther and gynoecium development.     

Site-specific integration and excision of pMEA100 in Nocardia mediterranei

Summary Nocardia mediterranei strain LBG A3136 contains the 23.7 kb element pMEA100 in a chromosomally integrated form as well as in the free state (Moretti et al. 1985). The integrated form of this element can be excised precisely from the Nocardia chromosome without any accompanying rearrangements in flanking chromosomal DNA. After transfer into plasmid-free mutant strains, pMEA100 reintegrates site specifically into its original chromosomal locus. The exact mapping of the pMEA100 integration site was accomplished by restriction analysis and DNA sequencing. The attachment site of pMEA100, the junctions of its integrated form and plasmid-free chromosomal DNA of N. mediterranei contain an identical 47 bp long sequence which is probably required for site-specific recombination connected with integration and excision of pMEA100. Only one such sequence was found in the chromosome of pMEA100-free N. mediterranei derivatives as suggested by the single integration locus.     

Interactions of nucleic acids with distamycins. The drug monomeric chromophore

A study of the monomeric chromophore of the oligopeptides netropsin (1), distamycin III (2), and distamycin V (3) by polarization spectroscopy techniques and molecular orbital calculations is reported. Linear dichroism spectra of the monomeric model compounds 1-methyl-2(ethylcarbamoyl)-4-acetamido-pyrrole (4) and 1-methyl-2(ethylcarbamoyl)-pyrrole (5) dissolved and oriented in lyotropic and thermotropic liquid crystals provide, together with the magnetic CD spectra, experimental checks of the theoretical calculations. The polarization directions of the investigated transition obtained by these means in this study allow us to build up in the following paper the exciton states of (1)-(3) and these provide a stereochemical interpretation of the flow linear dichroism spectra of the complexes of DNA with (2) and (3).     

Neurotransmitter, opiodergic system, steroid-hormone interaction and involvement in the replacement therapy of sexual disorders

Dopamine (DA) and serotonin (5-HT) are the neurotransmitters most directly involved in sexual activity. DA plays a stimulatory role while 5-HT has an inhibitory effect. The two monoaminergic systems modulate the secretion of many hormones (GnRH, LH, testosterone, prolactin and endorphins) involved in sexual functional capacity. Furthermore, hormones influence synthesis and storage of brain neurotransmitters. Impotence can often be associated to clinical depression and altered neurotransmitter function. Moreover, stress represents an unbalance between various neurotransmitter systems and can induce impotence especially when disorders of the endorphinic system are present. Replacement therapy is based upon the understanding of these basic concepts. Impotence due to an underlying depressive illness must be treated with dopaminergic antidepressant drugs; while in stressful conditions a good response to the naloxone test is the preliminary criterion to subsequent naltrexone treatment. When a hormonal deficiency has been proved, the hormone replacement therapy is of course highly effective (gonadotropins in hypogonadotropic syndromes, testosterone in aging, etc.). Finally, idiopathic impotence could be treated by DA agonist and/or 5-HT antagonist drugs either alone or better yet in association with psychotherapy.     

Oxidation of Ferrous Iron and Elemental Sulfur by Thiobacillus ferrooxidans

The oxidation of ferrous iron and elemental sulfur by Thiobacillus ferrooxidans that was absorbed and unabsorbed onto the surface of sulfur prills was studied. Unadsorbed sulfur-grown cells oxidized ferrous iron at a rate that was 3 to 7 times slower than that of ferrous iron-grown cells, but sulfur-grown cells were able to reach the oxidation rate of the ferrous iron-adapted cells after only 1.5 generations in a medium containing ferrous iron. Bacteria that were adsorbed to sulfur prills oxidized ferrous iron at a rate similar to that of unadsorbed sulfur-grown bacteria. They also showed the enhancement of ferrous iron oxidation activity in the presence of ferrous iron, even though sulfur continued to be available to the bacteria in this case. An increase in the level of rusticyanin together with the enhancement of the ferrous iron oxidation rate were observed in both sulfur-adsorbed and unadsorbed cells. On the other hand, sulfur oxidation by the adsorbed bacteria was not affected by the presence of ferrous iron in the medium. When bacteria that were adsorbed to sulfur prills were grown at a higher pH (ca. 2.5) in the presence of ferrous iron, they rapidly lost both ferrous iron and sulfur oxidation capacities and became inactive, apparently because of the deposition of a jarosite-like precipitate onto the surface to which they were attached.