Relationship between P700 turnover (m second) and NADP reduction as a function of ferredoxin concentration in isolated broken chloroplasts

Steady-state electron flux through P₇₀₀ (t $\text{1}\text{2}$ 20 msec) and concomitant rate of NADP reduction have been measured under weak actinic illumination as a function of concentration of ferredoxin added to broken chloroplasts isolated from peas. At suboptimal concentrations of ferredoxin this P₇₀₀ is not sufficient to account for the NADP reduction. At high concentrations ferredoxin inhibits the rate of NADP reduction without affecting the P₇₀₀ flux under short wavelength illumination. Under far red illumination P₇₀₀ flux is also inhibited by ferredoxin at high concentrations. Addition of 5 mM Mg⁺⁺ increases the rate of NADP reduction at all concentrations of ferredoxin under both kinds of illumination, while P₇₀₀ flux is inhibited under short wavelength illumination and remains unchanged under far red illumination. The results indicate that the observed (20 msec) P₇₀₀ is not involved in NADP reduction.     

Neue cadinan-derivate aus Heterotheca subaxillaris

The investigation of some Heterotheca species afforded three new cadinane angelicates, in addition to several known compounds. The structures are elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.     

Diterpenes with a new carbon skeleton from Printzia Laxa

The aerial parts of the South African composite Printzia laxa contain two manoyl oxides and three clerodane derivatives together with two further acids, which belong to a new type of diterpene, biogenetically closely related to the clerodanes. The structures have been elucidated by spectroscopic methods. The constituents may indicate some relationship of Printzia to the tribe Astereae.     

Neue guajanolide aus Lasthenia-arten

The investigation of two species of Lasthenia afforded two new guaianolides and a new bisabolone derivative, in addition to already known compounds. The presence of an eremophilenic acid in these plants is remarkable. The results are discussed chemotaxonomically, since the tribal position of this genus is still debated.     

Neue furanoeremophilane und andere sesquiterpene aus vertretern der gattung Euryops

Investigation of a further 27 Euryops species affords, besides known compounds, 55 new furanoeremophilanes together with several other compounds. The configuration of six furanoeremophilanes earlier given as 10β-H has to be changed to 10α-H. Furthermore 9 new eremophilenes were isolated; the configurations of four compounds of this type isolated before have had to be changed. One of the eremophilenes is esterified with 3-methylpent-3(E)-enoic acid, not found before in nature. Two hemiacetals, which are probable precursors of the furanoerephilanes, and a corresponding lactone are also present. Furthermore two benzylic esters, cis-caryophyllene, a bicyclo-germacrene derivative, and a new oplopanone derivative have been found. The structures are elucidated mainly by spectroscopic methods together with some chemical transformations. From the chemotaxonomic viewpoint, the high concentration of very variable furanoeremophilanes may be important. The proposed differentiation into sections however can not be clearly correlated with the chemical constituents, though some taxonomic conclusions seem to be supported by the chemical evidence.     

Cloning, sequencing, and expression of the genes encoding the adenosylcobalamin-dependent ethanolamine ammonia-lyase of Salmonella typhimurium

Ethanolamine ammonia-lyase is a bacterial enzyme that catalyzes the adenosylcobalamin-dependent conversion of certain vicinal amino alcohols to oxo compounds and ammonia. Studies of ethanolamine ammonia-lyase from Clostridium sp. and Escherichia coli have suggested that the enzyme is a heterodimer composed of subunits of Mr approximately 55,000 and 35,000. Using a partial Sau3A Salmonella typhimurium library ligated into pBR328 and selecting by complementation of a mutant lacking ethanolamine ammonia-lyase activity, we have cloned the genes for the 2 subunits of the S. typhimurium enzyme. The genes were localized to a 6.5-kilobase fragment of S. typhimurium DNA, from which they could be expressed in E. coli under noninducing conditions. Sequencing of a 2526-base pair portion of this 6.5-kilobase DNA fragment revealed two open reading frames separated by 21 base pairs. The open reading frames encoded proteins of 452 and 286 residues whose derived N-terminal sequences were identical to the N-terminal sequences of the 2 subunits of the E. coli ethanolamine ammonia-lyase, except that residue 16 of the large subunit was asparagine in the E. coli sequence and aspartic acid in the S. typhimurium sequence.     

A rapid fluorometric method for the estimation of DNA in cultured cells

We present here a procedure for the rapid measurement of both DNA and protein from the same aliquot of cell lysate. DNA estimates obtained by this method were compared to replicate determinations using the method of Kissane and Robins (1). The optimal range for the estimation of DNA (1 to 20 μg) is well suited for use with portions of extracts from individual cell cultures; the remainder of the extract remains available for enzyme assays or other parallel determinations.     

An isomer of xanthanol from Xanthium orientale

The aerial parts of Xanthium orientale afforded an isomer of xanthanol.