The ostrich (Struthio camelus) is a herbivorous bird and although the hindgut is known as the site for fiber digestion, little is known about the microbial diversity in the ostrich hindgut. Our aim was to analyze the microbial diversity in ostrich ceca using a 16S ribosomal RNA gene (rDNA) clone library approach. A total of 310 clones were sequenced and phylogenetically analyzed and were classified into 110 operational taxonomy units (OTUs) based on a 98% similarity criterion. The similarity of the sequences ranged from 86 to 99% and 95 OTUs had less than 98% similarity to the sequences in the public databases. Coverage and the Shannon-Wiener index (H') of the library were 83.9% and 4.29, respectively. The sequences were assigned to the following 6 phyla: Firmicutes (50.9% of the total number of sequences), Bacteroidetes (39.4%), Fibrobacteres (6.5%), Euryarchaeota (1.9%), Spirochaetes (1.0%), and Verrucomicrobia (0.3%); approximately 90% of the sequences were affiliated with Firmicutes and Bacteroidetes. The only OTU of Fibrobacteres (OTU 107), had 93 and 90% similarity to Fibrobacter succinogenes and F. intestinalis, respectively, suggesting a new species of Fibrobacter in ostrich ceca. Clostridium coccoides and C. leptum formed major groups within the Firmicutes. There was no OTU with high similarity (> or =98%) to the 16S rDNA of cultivated fibrolytic bacteria in our library. Although two OTUs were affiliated with Euryarchaeota, no sequence was affiliated with methanogenic Archaea. This study presents the very complex ostrich cecal microbial community, in which the majority of the bacterial species have not yet been cultivated.
The interest in carbenoids as useful intermediates for organic synthesis has recently grown a great deal.1-2 In contrast to many kinds of 'carbenoids' , free alkylidene 'carbenes' have not been as widely accepted as valuable species for the synthesis of natural products, although their generation by various methods and attractive reactions have been reported.3.4 Typical reactions of alkylidene carbenes are: intramolecular C-H insertion that leads to cyclopentene formation (reaction A in Scheme 1); intermolecular 0-H insertion with an alcohol that gives an enol ether (reaction B); and Fritsh-Buttenberg-Wiechell rearrangement that produces a terminal alkyne (reaction C). Reported here is a chiral synthesis of (-)-malyngolide 1,s an antibiotic from a bluegreen alga,6 using all three of these reactions.The cyclopentene 3 was prepared through intermolecular C-H insertion of the alkylidene carbene, which was generated
Novel Synthesis of (-)-Malyngolide Using Reactions of Alkylidene Carbenes.-A full step synthesis of (-)-malyngolide (X) and its epimer (XI) is presented. The formation of compounds (III) and (VII) proceeds via an alkylidene carbene biradical mechanism. -(OHIRA, S.; MORITANI, M.; IDA, T.; YAMATO, M.; J.
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