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The nucleotide sequences for codicin Ia and colicin Tb structural and immunity genes were determined. The two colicins each consist of 626 amino acid residues. Comparison of the two sequences along their lengths revealed that the two colicins are nearly identical in the N-terminal 426 amino acid residues. The C-terminal 220 amino acid residues of the colicins are only 60% The Col group of plasmids endows members of the family Enterobacteriaceae with the capacity to produce plasmidencoded protein toxins, termed colicins (20). Each Col plasmid also confers specific immunity via a second plasmid gene product, the immunity protein to the particular colicin produced. Over the years this laboratory has focused its interest on two closely related colicins, Ia and Ib, and their respective immunity proteins.Colicins Ia and lb are structurally related and adsorb to a common bacterial outer membrane receptor (19,21). Both have identical modes of action, depolarizing the energytransducing cytoplasmic membrane via formation of aqueous channels (45, 49). However, they differ in immunity specificity in that cells harboring the ColIb plasmid are immune to colicin Ib yet sensitive to Ia and vice versa (23). It has been proposed that the colicin I immunity system involves direct interaction of each colicin with its cognate immunity protein, which has been shown to reside in the cytoplasmic membrane (50). We previously reported that the C-terminal halves of the colicin Ta and lb molecules are responsible for immunity recognition (26). Hybrid colicins that contained the Nterminal half of one colicin and the C-terminal half of the other were found to have the immunity specificity of the colicin donating the C terminus. We report here the complete nucleotide sequences for both the colicin Ia and lb structural and immunity genes. Comparison of the two colicin sequences allows a more precise assignment of the immunity domain, localizing it within the C-terminal 200 amino acid residues. MATERIALS AND METHODSBacterial strains, plasmids, and media. Escherichia coli K-12 W3110 containing either pCol Ia-CA53 or pCol Ib-P9 was used as an indicator strain, as a source for colicin purification, and as a source for Col plasmid purification. JK481 (E. coli K-12 294), harboring plasmid pAR29 (50), was the source of the colicin Ia immunity gene. Plasmid pKC30 and E. coli K-12 Hi (4), which was used as a host for pKC30 and its derivatives, were obtained from K. Alton, Amgen, Inc., Thousand Oaks, Calif.LB, M9, and 2 x YT media were prepared as described by Miller (30). Antibiotic plates used for the selection of transformants contained LB medium and 50 ,ug of ampicillin per ml. M9 medium was supplemented with 1% Casamino Acids (Difco Laboratories, Detroit, Mich.), 0.2% glucose, 0.1% yeast extract, and 100 ,ug of ampicillin per ml. Methioninedeficient medium for protein labeling was M9 medium supplemented with 0.2% glucose, 0.01% yeast extract, and 0.5 p,g of each amino acid (no methionine) per ml, except for cysteine, which was 0.1 ,ug/ml.

Chemical investigation of the octocoral Sarcophyton ehrenbergi, collected at the Dongsha Islands, Taiwan, has led to the isolation of a known ceramide (1) and two new cerebrosides, sarcoehrenosides A (2) and B (4), along with three known cerebrosides (3, 5, and 6). The structures of the new compounds were established by spectroscopic and chemical methods. Sarcoehrenoside A (2) differs from previously known marine cerebrosides in that it possesses a rare alpha-glucose moiety. Compounds 1-6 were evaluated for antimicrobial activity against a small panel of bacteria and for anti-inflammatory activity using RAW 264.7 macrophages.

Although the zebrafish model provides an important platform for the study of developmental biology, recent work with the zebrafish model has extended its application to a wide variety of experimental studies relevant to human disease. Currently, the zebrafish model is used for the study of human genetic disease, caveolin-associated muscle disease, homeostasis, kidney development and disease, cancer, cardiovascular disorders, oxidative stress, caloric restriction, insulin-like pathways, angiogenesis, neurological diseases, liver disease, hemophilia, bacterial pathogenesis, apoptosis, osteoporosis, immunological studies, germ cell study, Bardet-Biedl syndrome gene (BBS11), Alzheimer's disease, virology studies and vaccine development. Here we describe the essential use of the zebrafish model that applies to several clinical diseases. With increased understanding of the cellular mechanisms responsible for disease, we can use knowledge gained from the zebrafish model for the development of therapeutics.

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Chemical investigation of the octocoral Sarcophyton ehrenbergi led to the isolation of six new cembranoids, (+)-12-carboxy-11Z-sarcophytoxide (1), (+)-12-methoxycarbonyl-11Z-sarcophine (3), ehrenberoxides A-C (4-6), and lobophynin C (2), along with two known compounds, (+)-sarcophytoxide (7) and (+)-sarcophine (8). The structures of these isolated metabolites were elucidated through extensive spectroscopic analyses, while the relative configuration of 1 was confirmed by X-ray diffraction analyses. The chemical evidence combined with spectroscopic and physical data suggested that the locations of the epoxide and the methyl carboxylate for lobophynin C should be exchanged. Moreover, metabolites 1-6 were evaluated in vitro for their cytotoxicity against selected cancer and normal cells lines, antiviral activity against human cytomegalovirus, and antibacterial activity against Salmonella enteritidis.

Chemical investigations of the soft coral Lobophytum durum have led to the isolation of three unprecedented hemiketal cembranolides, durumhemiketalolides A-C (1-3). Full NMR spectroscopic assignments are provided for all isolated metabolites. The anti-inflammatory activities of 1-3 were evaluated in vitro.

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