Weitere furanoeremophilane aus Othonna-arten

The investigation of further Othonna species affords 23 new furanoeremophilanes and a new benzofuran-derivative. All these compounds are closely related to those isolated before from other Othonna species. Highly oxidized furanoeremophilanes seem to be typical of this genus.     

New germacranolides from Isocarpha species

The investigation of two Isocarpha species has yielded eight new germacranolides most of them belonging to the heliangolides. In addition to known p-hydroxyacetophenone-derivatives, a new dihydroeuparine derivative was isolated. The chemotaxonomical aspects are discussed.     

Neue diterpene und germacranolide aus Mikania-Arten

From three Mikania species, three new labdanic acid and two kaurenic acid derivatives have been isolated together with known compounds and four new germacranolides, differing only in the ester moiety.     

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.     

Neue sesqui- und diterpene aus Bedfordia salicina

An Australian member of the tribe Senecioneae, Bedfordia salicina, contains besides known compounds new dimeric eremophilenolides, new kolevane derivatives, a kaurenic acid and several further sesquiterpenes, most of them related to xanthatine. The structures are elucidated mainly by spectroscopic methods and by some chemical transformations. The chemotaxonomic aspects of these findings are discussed briefly.     

Neue phloroglucin-derivate aus Leontonyx-arten sowie weitere verbindungen aus vertretern der tribus inuleae

The investigation of several South African species of the tribe Inuleae afforded in addition to known compounds 16 new constituents. From Leontonyx a group of 9 new phloroglucinol derivatives, from Stoebe species two new p-hydroxyacetophenone, two thymol and two coumaric acid derivatives and from Relhania a new euparine-derivative were isolated. The structures are elucidated mainly by spectroscopic methods. The chemotaxonomic aspects are discussed briefly. The phloroglucinol derivatives, which in part are derived from geraniol, seem to be especially characteristic.     

Assimilatory Sulfur Metabolism in Marine Microorganisms: Considerations for the Application of Sulfate Incorporation into Protein as a Measurement of Natural Population Protein Synthesis

The sulfur content of residue protein was determined for pure cultures of Nitrosococcus oceanus, Desulfovibrio salexigens, 4 mixed populations of fermentative bacteria, 22 samples from mixed natural population enrichments, and 11 nutritionally and morphologically distinct isolates from enrichments of Sargasso Sea water. The average 1.09 ± 0.14% (by weight) S in protein for 13 pure cultures agrees with the 1.1% calculated from average protein composition. An operational value encompassing all mixed population and pure culture measurements has a coefficient of variation of only 15.1% (n = 41). Short-term [³⁵S]sulfate incorporation kinetics by Pseudomonas halodurans and Alteromonas luteoviolaceus demonstrated a rapid appearance of ³⁵S in the residue protein fraction which was well modelled by a simple exponential uptake equation. This indicates that little error in protein synthesis determination results from isotope dilution by endogenous pools of sulfur-containing compounds. Methionine effectively competed with sulfate for protein synthesis in P. halodurans at high concentrations (10 μM), but had much less influence at 1 μM. Cystine competed less effectively with sulfate, and glutathione did not detectably reduce sulfate-S incorporation into protein. [³⁵S]sulfate incorporation was compared with [¹⁴C]glucose assimilation in a eutrophic brackish-water environment. Both tracers yielded similar results for the first 8 h of incubation, but a secondary growth phase was observed only with ³⁵S. Redistribution of ¹⁴C from low-molecular-weight materials into residue protein indicated additional protein synthesis. [³⁵S]sulfate incorporation into residue protein by marine bacteria can be used to quantitatively measure bacterial protein synthesis in unenriched mixed populations of marine bacteria.