No abstract

A method to extract and concentrate intact human enteric viruses from oyster extracts for detection using reverse transcription-polymerase chain reaction (RT-PCR) was applied to hard-shelled clams (mercenaria mercenaria). Fifty-gram clam samples were processed by an adsorption-elution-precipitation method and then seeded with 10(1) to 10(5) PFU to poliovirus 1 (PV1) and/or hepatitis A virus (HAV). Seeded viruses in extracts were purified by fluorocarbon (Freon) extraction and concentrated by polyethylene glycol (PEG) precipitation and elution. Efficiency of virion recovery from PEG precipitates was dependent upon PEG concentration and elution buffer volume, with optimized variable yielding recoveries as high as 99% for PV1 and 45% for HAV, as evaluated by cell culture infectivity assay. To further concentrate viruses, remove inhibitors, and reduce sample volumes, the protein-precipitating agent Pro-Cipitate was used in an adsorption-elution-precipitation scheme. The final concentrate was of low volume (< 1 ml) and directly compatible with viral genomic amplification using RT-PCR. When extracts from 50-g clam samples were seeded and processed by the combined concentration and purification scheme, direct RT-PCR detection of viral genomic RNA was possible at initial inoculum levels of 10(3) PFU for PV1 and HAV. Corresponding virus recoveries based on cell culture infectivity were 7 to 50% and 0.3 to 8% for pV1 and HAV, respectively, when extracts of clams were artificially contaminated with the Norwalk virus, direct detection of virion RNA using RT-PCR and subsequent oligoprobe hybridization was possible at levels as low as 450 RT-PCR amplifiable units of the Norwalk virus per extract of 50-g clam sample.

In our search for fungal metabolites with antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), we have isolated three different setin antibiotics from several different fungi-the previously reported equisetin (2)1) and trichosetin (3),2) and a novel setin-like compound (1) from OSI 50185. Like the known setin antibiotics, cissetin (1) is active against several Grampositive organisms,2-5) but it is most notable for the atypical cis ring fusion in the octalin portion of the molecule.Cissetin (1) was isolated from OSI 50185 as a white foamy powder for which positive ion detection HR-FAB-MS suggested a molecular formula of C23H33NO4 [m/z, found 388.24893 (M+H)+, calcd 388.24892]. In contrast to reports of the NMR data for the setin class as extremely broad and ill-defined,1-5) 1 gave crisp, clean 1H and 13C NMR spectra in CDCl3 at ambient temperature (Table 1)

Fusion. -Cissetin (I) is isolated from the fungus OSI 50185 along with two known compounds. (I) is active against penicillin-resistant Streptococcus albicans. -(BOROS*, C.; DIX, A.; KATZ, B.; VASINA, Y.; PEARCE, C.; J. Antibiot. 56 (2003) 10, 862-865; Mycosynthetix Inc., Durham, NC 27707, USA; Eng.) -M. Bohle 13-194

Peptides U 0400Isolation and Identification of the Icosalides -Cyclic Peptolides with Selective Antibiotic and Cytotoxic Activities. -The new cyclic depsipeptides (I) and (II) are extracted from two different fungal species found on dead ground wood in a tropical rain forest. Icosalide A1 (I) displays antimicrobial activity and icosalides A2 (IIa) and B (IIb) are cytotoxic to replicating MDCK cells. The unusual D-leucine moiety in (I) is an interesting deviation from the predomination of L-amino acids. -(BOROS*, C.; SMITH, C. J.; VASINA, Y.; CHE, Y.; DIX, A. B.; DARVEAUX, B.; PEARCE, C.; J. Antibiot. 59 (2006) 8, 486-494; MYCOsearch, OSI Pharm., Durham, NC 27707, USA; Eng.) -H. Haber 08-182