Tertiary coals exposed in the north-central part of onshore Sarawak are evaluated, and their depositional environments are interpreted. Total organic carbon contents (TOC) of the coals range from 58.1 to 80.9 wt. % and yield hydrogen index values ranging from 282 to 510 mg HC/g TOC with low oxygen index values, consistent with Type II and mixed Type II–III kerogens. The coal samples have vitrin...

Herein we address the total synthesis of the natural product oasomycin A by assembly of the C1–C12, C13–C28, and C29–C46 subunits, whose syntheses have been described in the preceding Communications. The synthesis plan (Scheme 1) incorporates a speculative late-stage macrolactonization of the linear seco acid precursor to form a 42-membered lactone that upon global deprotection would provide th...

An attempt was made to knockout the Escherichia coli C29 lacI gene with a kanamycin resistance cassette isolated from the plasmid pACYC177. This process used the lambdared recombinase system to allow for homologous recombination, and subsequent insertion of the kanamycin cassette into the lacI gene. The E. coli C29 cells were initially transformed with pKD46, which contains the lambda-red recom...

In social insects, cuticular hydrocarbons are involved in species, kin, caste and nestmate recognition. Gas chromatography and mass spectrometry were used to compare the cuticular hydrocarbon composition of workers, males and queens of Melipona bicolor. The cuticular hydrocarbon composition of this species was found to consist mainly of C23, C25:1, C25, C27:1, C27, C29:1 and C29, which are alre...

Gas chromatography (GC), gas chromatography±mass spectrometry (GC±MS) and gas chromatography±mass spectrometry±mass spectrometry (GC±MS±MS) with co-injected synthetic standards were used to analyse the biomarker patterns of some Tertiary lacustrine clayey dolomites from the Biyang Basin, China. The lithology, low Pr/Ph ratio and high gammacerane content of these sediments indicated that high sa...

Abstract Protomyces is an understudied genus of yeast-like fungi currently defined as phytopathogens only Umbelliferae and Compositae . Species relationships boundaries remain controversial molecular data are lacking. Of the 82 named Protomyces, we found few recent studies six available cultures. We previously isolated strains from wild Arabidopsis thaliana, a member Brassicaceae , family dista...

The microbial degradation of two Venezuelan crude oils enriched in 25-norhopanes was examined after a 5-week aerobic incubation using a microbial enrichment culture. Analysis of the oils using gas chromatography±mass spectrometry revealed degradation of the C28 tricyclic terpane, the C29±C34 17a(H),21b(H)-hopanes, and the C29 17a(H),21b(H)-25-norhopane. The C35 17a(H),21b(H)-hopane and 18a(H)-o...

Contact pheromones in the form of cuticular hydrocarbons are widespread among insects. Eusocial insects present a special challenge for understanding the evolution of the cuticular hydrocarbon profile because this blend is responsible for multiple distinct roles such as nestmate recognition and signalling fertility status. This study investigates these two signalling roles of the hydrocarbon pr...