Isolation of oligomeric proanthocyanidins from flavonoid-producing cell cultures

Summary The extraction, fractionation, and chromatographic separation of a series of proanthocyanidin monomers and oligomers were facilitated using a flavonoid-rich cell culture of Vaccinium pahalae Skottsberg as the donor tissue. The cell cultures, after exposure to light, readily accumulated anthocyanin pigments and other flavonoids in relatively large amounts, with minimal concurrent production of pectins, enzymes, and complex sugars produced in field-grown Vaccinium berries. The absence of these interfering compounds greatly simplified the isolation and purification of proanthocyanidins and other phenolic compounds from cell cultures, primarily using vacuum chromatography. Subsequently, the structures and molecular weights of several individual compounds and the general composition of unresolved fractions were established with ¹H- and ¹³C-NMR and MS. The initial extract of V. pahalae cell cultures was readily fractionated on silica gel to yield a series of fractions containing proanthocyanidin B-2, a series of increasingly polar proanthocyanidin oligomers ranging from dimers to heptamers largely based on (−)-epicatechin structures (some with A-type linkages), a mixture of E- and Z-p-coumaric acid, the corresponding 4-O-glucoside, and other compounds containing E- and Z-p-coumaric acid moieties. Cell culture extracts demonstrated broad antioxidant capacity and significant ability to inhibit tumor promotion in vitro, as indicated in an ornithine decarboxylase assay.     

Production of prostaglandin-like substance at the time of mating in the rat.

The amount of prostaglandin-like substance (PG--LS) in the reproductive tract of the male and female rat following mating (p.c.) has been measured and compared with non-mated (control) values. Negligable amounts of PG-LS were detected in the control female tracts but a mean of 2 mug PGE, equivalents was detected immediately p.c. The PG--LS is probably generated in the vas deferens since nearly 1 mug PGE1 equivalents per rat remained there p.c. No other tissue in the male reproductive tract contained significant amounts of PG--LS suggests that the bulk of the activity is due to PGE2 with a smaller amount being due to PGF2 alpha.     

Tardigrades of South America: Machu Picchu and Ollantaytambo, Peru

During July 1999, a study group from the University of Kansas visited the ancient Inca ruins in and around Machu Picchu and Ollantaytambo, Peru. They collected lichens and mosses from the rock walls around the ruins. The samples contained four genera and six species of tardigrades. No associational patterns and relationships were detected. A new species, Echiniscus ollantaytamboensis nov. sp. is described.     

Determination of ochratoxin A by immunoaffinity column clean-up and HPLC In wheat and pig liver

Determination of ochratoxin A (OTA) by immunoaffinity column clean-up and HPLC detection was performed on wheat and pig liver. Several extraction protocols involving methanol and ethyl acetate were investigated. The optimum experimental conditions for analysis of OTA in artificially contaminated wheat (87.4% recovery) using immunoaffinity column clean-up was found to be the methanol: PBS (1∶1 v/v) protocol. These conditions, however, gave low recoveries for pig liver (40.4%).