Eremophilane derivatives and other constituents from Senecio species

The investigation and reinvestigation respectively of 23 Senecio species afforded 11 further cacalol derivatives, a furoeremophilone, 17 eremophilanes, 4 bisabolene derivatives, a shikimic acid derivative, a bis-prenylated p-hydroxybenzaldehyde, menth-2-en- 1,7-diol and a cumol derivative. The configuration of some eremophilanes have been revised. Structures were elucidated by spectroscopic methods. The results are summarized in a table. The chemotaxonomic aspects agree with those of previous investigations.     

Guaianolides,heliangolides, diterpenes and cycloartenol derivatives from Balsamorhiza sagittata

Investigation of the aerial parts of Balsamorhiza sagittata afforded 12 new sesquiterpene lactones, five guaianolides, three heliangolides, three germacranolides and two geranylnerol derivatives. From the roots eight cycloartane derivatives, a hydroxylanosterone and hexacos-1-ene were isolated. Structures were elucidated mainly by spectroscopic methods, especially high field NMR. The chemotaxonomic situation is discussed briefly.     

Eudesmanolides and costic acid derivatives from Flourensia macrophylla

The aerial parts of Flourensia macrophylla afforded, in addition to compounds similar to those from other Flourensia species, four new eudesman     

2-Oxo-labda-8(17),13-dien-15-OL from Ophryosporus chilca

The aerial parts of Ophryosporus chilca afforded several prenylated p-hydroxyacetophenones, two labdane derivatives and a cinnamyl ester. Ophryosporus peruvianus also contains prenylated p-hydroxyacetophenones. Three compounds were isolated for the first time; their structures were established by ¹H NMR spectroscopy.     

Ultrastructural Studies on Gametogenesis of the Prawn Palaemon serratus (Pennant). II. Spermiogenesis

Spermiogenesis in Palaemon serratus is described. The mature sperm has an atypical form and is highly modified. In early stages of spermiogenesis mitochondria, golgi complexes, stacks of annulate lamellae and endoplasmic reticulum are present but disappear later in development. Two modified mitochondria are present in the mature sperm. This latter consists of a cup-shaped nucleus, a cross-striated “spike”, has a centriole and lacks an acrosome. The nucleus contains membrane-bounded vesicles which arise by pinocytosis. The “spike” may be a flexible posterior organ which suggests a mode of fertilization requiring limited mobility.     

Low-frequency dynamics of solid poly(L-alanine) from Raman spectroscopy

Raman modes from amorphous α-helical poly(L -alanine) in the low-frequency region < 150 cm^?1 have been observed and assignments and values compared with mode-analysis calculations. The temperature dependence of the complete Raman spectrum of α-poly(L -Ala) is also reported.     

Ein neues germacren-derivat sowie ein diterpenmalonat aus Baccharis-arten

The investigation of the aerial part of B. scandens afforded a new ketone, a germacrene derivative. The aerial parts of B. tricuneata var. lineata yielded, in addition to known ent-clerodane derivatives, a malonate of a further diterpene of this type. The structures are elucidated by spectroscopic methods.     

Multiple independent evolutionary solutions to core histone gene regulation

Background  

Core histone genes are periodically expressed along the cell cycle and peak during S phase. Core histone gene expression is deeply evolutionarily conserved from the yeast Saccharomyces cerevisiae to human.     

Functional bioinformatics for Arabidopsis thaliana

The authors would