Cryptospore Assemblages from the Ordovician/silurian Boundary in the Puna Region, North-west Argentina

Palynomorph assemblages have been recovered from deposits believed to straddle the Ordovician/Silurian boundary, from the upper member of the Salar del Rincón Formation, in the Puna region of north-west Argentina. The palynomorph assemblages are dominated by terrestrial cryptospores, but also contain marine elements (acritarchs, prasinophycean algae and chitinozoans). The cryptospore assemblages are similar in composition to those described from coeval deposits worldwide, suggesting that the producers were cosmopolitan and tolerated a wide range of climatic conditions. They are correlated with the Imperfectotriletes spp. Interval Biozone (sub-biozone α) of the Imperfectotriletes spp.- Laevolancis divellomedia Assemblage Biozone, indicating a Hirnantian (latest Ordovician) age. Acritarchs include late Ordovician species such as Eupoikilosusa striata and Villosacapsula cf. setosapellicula , that coexist with the Llandovery species Dactylofusa estillis. Based on lithological and palynological evidence, an early Llandovery, or a late Hirnantian (post-glacial) age is proposed for the basal part of the upper member of the Salar del Rincón Formation.     

Formaldehyde-derived tetrahydroisoquinolines and tetrahydro-β-carbolines in human urine

Human urine samples were examined for the occurrence of formaldehyde-derived tetrahydroisoquinolines and tetrahydro-β-carbolines generated by condensation of the methanol oxidation product with biogenic amines. Positive results were obtained for the tryptamine condensation product 1,2,3,4-tetrahydro-β-carboline and the serotonine condensation product 6-hydroxy-1,2,3,4-tetrahydro-β-carboline as well as for the condensation products with tyramine, dopamine, adrenaline and noradrenaline 1,2,3,4-tetrahydroisoquinoline, 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, N-methyl-4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline, 4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline, and the metabolite 6-methoxy-7-hydroxy-1,2,3,4-tetrahydroisoquinoline. Negative results were obtained for N-methyl-1,2,3,4-tetrahydroisoquinoline and 6,7-di-methoxy-1,2,3,4-tetrahydroisoquinoline, N-methyl-1,2,3,4-tetrahydro-β-carboline, 6-methyl-1,2,3,4-tetrahydro-β-carboline, and 6-methoxy-1,2,3,4-tetrahydro-β-carboline in samples of chronic alcoholics as well as in the urine of healthy volunteers. No correlation between alcohol ingestion or state of alcoholization could be demonstrated.     

Chromatographic methods for amylases

This review surveys recent developments in chromatographic methods for the separation of amylases from complex extracts, including the separation of isozymes. It contains two tables with the properties and molecular characteristics of α- and β-amylases from different sources as well as an updated review of methods for the determination of amylase activity. The main subject of this review is a detailed evaluation of the application of newly developed chromatographic methods for the purification of amylases.     

Aqueous plant extracts as stimulators of laccase production in liquid cultures of Lentinus edodes

Summary Total and specific activities of extra-cellular laccases from Lentinus edodes were enhanced by adding corn straw and chestnut juice to the liquid growth medium. The aqueous extracts were chemically characterized and revealed the presence of several phenolic and non-phenolic compounds. Extensive extraction of these components from the tested extracts completely annulled their stimulating properties on laccase production, suggesting that these compounds can act at micromole levels.     

A sensitive RNase protection assay using33P labeled antisense riboprobes

This article presents for the first time a modified protocol for RNase protection analysis that allows the substitution of³²P with³³P without loss of the high sensitivity of this method achieved with³²P. With this protocol, we were able to detect at least 1 pg of specific mRNA. In the RNase protection analysis³³P labeled riboprobes are more advantageous with regard to an easier handling and better resolution.