Quantitative analysis of abscisic acid in needles of Abies alba Mill. by electron capture gas chromatography

Summary The amount of abscisic acid (ABA) in needles of silver fir from a natural location was investigated with regard to position in the crown, damage, seasonal variation, and needle age. Because of problems of quantification of ABA in coniferous needles, which contain numerous secondary plant products, a method for reliable determination of both isomers cis-trans-ABA (c-ABA) and transtrans-ABA (t-ABA) was developed. By means of gas chromatography (GC) using an electron capture detector (BCD) and a programmed temperature vaporizer (PTV) injector complete separation of both compounds was achieved. Two different pairs of fir were investigated — in each case a damaged and a healthy tree. Needles from both trees from the first and the second pair collected in September contained 500–1100 ng c-ABA/g fresh weight (FW), and the concentrations of t-ABA varied from 400 to 700 ng/g FW. Investigations from the second pair show highest amounts of 2900 ng/g Fw c-ABA and 1800 ng/g FW of t-ABA in May and June. For the first pair a higher c-ABA content was found in needles from the top of the crown than in those from the middle and the base. This difference could not be confirmed in the analysis of the second pair. Because of the strong natural deviation no statistically significant difference between the healthy and the damaged tree was found. The first pair of firs examined showed a higher t-ABA concentration than the second one. In this case the highest amount was found in the top of the crown. Methodical mistakes during the clean-up procedure and in quantification by gas chromatography could be excluded. The presence of c- and t-ABA in the purified extract was corroborated by mass spectrometry. With regard to the seasonal variation both isomers of ABA show an unequivocal trend. The maximum concentration is achieved in May to June, whereas the content is minimal in August/September. In any case the level of t-ABA is lower than that of c-ABA. No correlation between the amount of ABA and the needle age could be established.     

Sensory Spots of Echinoderes capitatus (Zelinka, 1928) (Kinorhyncha,Cyclorhagida)

The sensory spots of Echinoderes capitatus from the Gulf of Trieste were examined by transmission and scanning electron microscopy. Their arrangement is bilaterally symmetrical and is species-specific. At the cuticle surface the sensory spot appears as a rounded to ovoid area of small cuticular papillae in which two pores open. The sensory organ consists of two different sensory cells, the monociliary receptor and the collar receptor, and one sheath cell. The course of the axons and their connections to the nervous system are described. A survey of collar receptors among invertebrates is given. A comparison of the sensory spots within Kinorhyncha and a comparison with the flosculi of Priapulida and the N-flosculi of Loricifera is made. A possible homology of these three structures is discussed.     

Biochemical and immunocytochemical characterization of monoclonal antibody TOP 35 raised against purified tonoplast from cress root

The vacuolar membrane, the tonoplast, is a proteinrich membranehitherto only few proteins in it have been identified. As anapproach for the identification of tonoplast proteins by monoclonalantibodies (MABs), purified tonoplast from cress roots (Lepidiumsativum L.) were used for immunization and plasma membranesas a control membrane to test the absence of antigen. The MABTOP 35 identified a glycoprotein of about 35 kDa in purifiedtonoplast of cress roots. Triton X-114 phase separation showedthat it was a hydrophobic integral membrane protein. In immunocytochemistrythe MAB TOP 35 strongly labelled the vacuolar membrane. Theabsence of cell wall or plasma membrane labelling by TOP 35indicates a distinct biosynthetic pathway of this protein tothe vacuolar membrane in plants. Key words: Immnocytochemistry, Lepidium sativum, monoclonal antibody, secretion, vacuole     

Interaction of metabolic inhibitors with actin fibrils

Summary The dependence of the arrangement of fibrillar actin in cultured endothelial cells on metabolic conditions was investigated with cellular elements derived from the heart of Xenopus laevis tadpoles. Either primary culture or an established cell line (XTH-2) were used in these studies The metabolic stage of the cells was influenced by inhibiting respiration and lactate production. The actin pattern was revealed either by indirect immunofluorescence or by tetramethylrhodaminyl (TRITC)-phalloidin fluorescence. Total block of energy supply causes in all cases a distinct loss of actin fibrils, while inhibition of respiration alone increases the variability of actin organization. In primary XTH cells but not in XTH-2 cells cyanide disintegrates most of the actin fibres during 3 h of treatment. This effect is independent of the inhibition of respiration, since actin gels prepared from skeletal muscle also undergo destruction in the presence of cyanide. It is concluded that the actin fibrils of the primary cells and the established line behave differently to changing metabolic conditions and to application of KCN.     

An automatic method for determination of urinary 3-methylhistidine: normal values.

A system for automatic analysis of urinary 3-methylhistidine is described, applying ion-exchange chromatography and using an automatic sample injector, a motoric selector valve, and a diode programmer, which controls the analytical system. The method permits a sampling rate of 22 samples/day. 3-Methylhistidine was completely separated from histidine in 37 min whereas 1-methylhistidine was eluted together with ammonia. The 3-methylhistidine concentration was linear up to 150 nmol/ml and no appreciable sample interaction was found at automatic sequential runs. The error, in a single determination based on duplicate samples, was 4.61% and, in duplicated determinations, 3.26%. The mean urinary 3-methylhistidine output was 299.4 ± 23.8 μmol/day in 12 healthy females and 545.5 ± 35.2 μmol/day in 12 healthy males. The 3-methylhistidine excretion was significantly higher in males than in females, when expressed as the absolute daily output or as the estimated ratio to body weight, body surface area, or creatinine.     

Sexual dimorphism of blood pressure: Possible role of the renin-angiotensin system

The prevalence of hypertension in men is higher than in women and the onset of this disease is earlier in male than in female subjects. In spontaneously hypertensive rats, males also have higher blood pressures than females. Evidence from epidemiological, physiological, molecular biological and morphological studies concerning this sexual dimorphism is reviewed. We demonstrate that the gonadal steroids testosterone and estrogen have important effects on the gene regulation of the renin-angiotensin system. This may in part contribute to the sexual dimorphism in blood pressure control. The direct effect of steroid hormones on genes related to hypertension provides a suitable paradigm to improve our understanding of molecular and cellular mechanisms of cardiovascular control.     

Optimizing the production of transformed pea (Pisum sativum L.) callus using disarmed Agrobacterium tumefaciens strains

For optimization of the transformation procedure with Pisum sativum L. stern explant callus was used to test the effect of disarmed Agrobacterium tumefaciens strains, cocultivation procedures (preconditioning of explants; use of Nicotiana tabacum L. nurse cultures), duration of cocultivation (2, 3 or 4 days), and agents for selection (kanamycin or hygromycin). The succinamopine strain EHA101(pBI1042) produced the highest percentage of transformed calli (77%) when used in conjunction with tobacco nurse culture during four days of cocultivation. Using this strain, kanamycin (76%) and hygromycin (77%) were equally effective selective agents, but for strain LBA4404(pBI1042) percentage of transformed calli was higher for hygromycin (63%) than for kanamycin (17%). The procedures and strains shown to be optimal for transformation of pea callus will now be complemented by a pea regeneration system.