UDP-glucose:isoflavone 7-O-glucosyltransferase from roots of chick pea (Cicer arietinum L.)

A glucosyltransferase which catalyzes the glucosylation of isoflavones in position 7 using uridine diphosphate glucose as glucosyl donor has been purified about 120-fold from 4-day-old roots of chick pea (Cicer arietinum L.). The soluble enzyme showed a pH optimum of 8.5–9.0 and a molecular weight of 50,000. The K_m for uridine diphosphate glucose was 200 μm and for the isoflavones biochanin A and formononetin, 12 and 24 μm, respectively. While the aforementioned 4′-methoxy isoflavones were the best substrates, the 4′-hydroxy isoflavones genistein and daidzein were poor substrates. The enzyme was unable to catalyze the glucosylation of hydroxy substitutes isoflavanones, flavones, flavanones, flavonols, coumarins, cinnamic acids, and benzoic acids.     

Luteinizing hormone stimulates the production of prostacyclin by isolated ovarian cell invitro

Granulosa cells isolated from mature Graafian follicles of swine produced significant quantities of immunoreactive 6-keto-PGF₁α under chemically defined conditions in vitro. Luteinizing hormone elicited a dose-dependent stimulation of 6-keto-PGF₁α accumulation, but follicle stimulating hormone, prolactin, L-epinephrine, estradiol-17B, or PGE₂ were devoid of effect. The time-dependent in vitro production of 6-keto-PGF₁α by ovarian cells was susceptible to inhibition by indomethacin, U-51506, cycloheximide, and actinomycin D. These observations implicate granulosa cells in the specific and hormonally regulated production of prostacyclin.     

The effect of leucotriene C4 and D4 on cutaneous blood flow in humans

Using a laser-Doppler-flowmeter the microvascular response to LTC₄ and LTD₄ was measured. Intradermal injection of 1 Ug LTC₄ and LTD₄ caused an increase in the microvascular cutaneous bloodflow. The increase in flow was equal to that caused by histamine in equimolar amounts. Blocking the triple-response did not change the response. The values measured after injection of histamine and leucotrienes were about 10–15 times the values found in undisturbed skin and represents probably a maximally dilated vascular bed. Injection of the leucotrienes caused a slight sensation of pain.     

Fine structure of the 21S ribosomal RNA region on yeast mitochondrial DNA

Summary The omega locus controls the polarity of recombination and transmission of genetic markers in the 21S ribosomal RNA region in yeast mtDNA. Polarity is observed in crosses between omega⁺ and omega^- strains. These two strains differ by the presence of an intervening sequence in the 21S ribosomal RNA gene of omega⁺ strains. Mutations of the omega^- allele, omega neutral (omegaⁿ), can eliminate the polarity effect. We have made DNA:RNA hybrids containing ribosomal RNA from an omegaⁿ strain and mtDNA from Saccharomyces carlsbergensis (identical to omega^- in the nucleotide sequence of the omega region). These hybrids contain no mismatch at the omega region detectable by digestion with S₁ nuclease. We conclude that omegaⁿ differs from omega^- only in a point mutation or analogous small alteration and that the omegaⁿ mutation can result either m a C^r phenotype (omegaⁿC^r) or in the phenotypic suppression of pre-existing C^r mutations (omegaⁿC^s). All results can be explained by a model which postulates interaction in the ribosome between the C^r and omegaⁿ regions of the ribosomal RNA and interference of the omegaⁿ mutation with splicing of the precursor ribosomal RNA in omega⁺ strains. The mechanism of omega-directed polarity is discussed.Abbreviations rRNA ribosomal RNA - bp base pair(s) - kb kilo base pair(s)     

Nesting,eggs and larvae of triggerfishes (Balistidae)

Synopsis Triggerfishes construct nests by excavating depressions in sand. Eggs are laid in an adhesive mass and anchored with rubble. A photograph of a newly-hatched embryo is included.     

Esterase-16 (Es-16): Characterization,polymorphism, and linkage to chromosome 3 of a kidney esterase locus of the house mouse

A polymorphism for an isozyme of a presumed arylesterase, esterase-16 (EC 3.1.1.2), has been detected in kidney, heart, and spleen of the house mouse, Mus musculus, by means of isoelectric focusing and by disc electrophoresis. Three phenotypes can be distinguished: the ES-16A phenotype (IEP 5.9) was found in C57BL/10Sn and many other laboratory inbred strains; the ES-16B phenotype (IEP 6.1) was found in M. m. molossinus; and the ES-16C phenotype (IEP 5.9; very weak activity) was found in Peru-Coppock. Esterase-16 is strongly inhibited by 10^?3 m p-chloromercuribenzoate, but not by 2·10^?4 m bis-p-nitrophenyl phosphate or by 10^?3 m Diamox. It stains well with indoxyl acetate and other indigogenic substrates but only weakly with α-naphthyl acetate. Esterase-16 is completely insoluble in water. It is apparently governed by a structural gene locus, Es-16, with three alleles, Es-16 ^a , Es-16^b, and Es-16 ^c, respectively. Es-16 is closely linked to Car-1 and Car-2 on chromosome 3. Typing of 94 animals of the backcross (C57BL/10Sn × M. m. mol.) F₁ × M. m. mol. revealed a recombination frequency of 8.51±2.9%.     

Rapid effects of nerve growth factor on the Na,K-pump in rat pheochromocytoma cells

Nerve growth factor (NGF) induces neuronal differentiation of rat pheochromocytoma cells (PC12). Here we show that NGF causes a stimulation of Na⁺,K⁺-pump mediated K⁺ influx, with a maximum at 30 min after addition of NGF. The stimulation of the Na⁺,K⁺-pump is completely blocked by the Na⁺-flux inhibitor amiloride (0.2 mM) and can be mimicked by the Na⁺ ionophore monensin. These results suggest that NGF causes a rapid enhancement of Na⁺ influx leading to an activation of the Na⁺,K⁺-pump, a mechanism similar to the action of other growth factors.     

Einbau von 14C-mevalonsäurelacton in hopfenbitterstoffe

Labeled mevalonate is incorporated into terpenes and hop bitter compounds by Humulus lupulus. The role of mevalonate as a precursor for the prenyl (3-methyl-but-2-enyl) side chain of the hop bitter compounds is discussed.     

Configurational assignments of C-nitromethyl-C-hydroxy branched-chain carbohydrate derivatives by use of a europium shift-reagent in 1 H-N.M.R. spectroscopy

Configurational assignments for the tertiary alcoholic centers of four branched-chain 3-C-nitromethylglycopyranosides, namely, methyl 2-benzamido-4,6-O-benzylidene-2-deoxy-3-C-nitromethyl-α-D-allopyranoside (1), benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-3-C-nitromethyl-α-D-glucopyranoside (4), benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-3-C-nitromethyl-α-D-allopyranoside (5), and methyl 4,6-O-benzylidene-3-C-nitromethyl-2-O-p-tolylsulfonyl-α-D-glucopyranoside (8), were made on the basis of the downfield chemical shifts of their identifiable protons per molar equivalent of added Eu(fod)₃, as compared with those of model compounds, of known configuration, having a close structural relationship. In some cases, the assignments were corroborated by the position of the acetyl resonances in the unshifted 60-MHz p.m.r. spectra of the corresponding O-acetyl derivatives.