Variability of the fatty acid composition during development of the green microalga Apatococcus constipatus

The green microalga Apatococcus constipatus was investigated for its fatty acid composition using GC and MS techniques. Considerable variations were found in individual fatty acid contents according to the stage of culture development. A set of saturated fatty acid homologues was distinguished as the main component regardless of the culture age. The occurrence of some uncommon fatty acids in minor amounts, such as hydroxylated ones, was found to be characteristic of the studied species. Depending on the development stage, those compounds were detected either only during initial growth phases or throughout the cultivation time.     

Three differentially expressed S-adenosylmethionine synthetases from Catharanthus roseus: molecular and functional characterization

We describe the molecular and functional characterization of three closely related S-adenosyl-L-methionine synthetase (SAMS) isoenzymes from Catharanthus roseus (Madagascar periwinkle). The genes are differentially expressed in cell cultures during growth of the culture and after application of various stresses (elicitor, nutritional down-shift, increased NaCl). Seedlings revealed organ-specific expression and differential gene regulation after salt stress. A relationship analysis indicated that plant SAMS group in two main clusters distinguished by characteristic amino acid exchanges at specific positions, and this suggested differences in the enzyme properties or the regulation. SAMS1 and SAMS2 are of type I and SAMS3 is of type II. The properties of the isoenzymes were compared after heterologous expression of the individual enzymes, but no significant differences were detected in a) optima for temperature (37 to 45 °C) or pH (7 to 8.3); b) dependence on cations (divalent: Mg2+, Mn2+, Co2+; monovalent: K+, , Na+); c) Kms for ATP and L-methionine; d) inhibition by reaction products (S-adenosyl-L-methionine, PPi, Pi), by the reaction intermediate tripolyphosphate, and by the substrate analogues ethionine and cycloleucine; e) response to metabolites from the methyl cycle (L-homocysteine) or from related pathways (L-ornithine, putrescine, spermidine, spermine); f) native protein size (gel permeation chromatography). The results represent the first characterization of plant SAMS isoenzyme properties with individually expressed proteins. The possibility is discussed that the isoenzyme differences reflect specificities in the association with enzymes that use S-adenosyl-L-methionine.     

Management of calcareous grasslands for Nickerl’s fritillary (<Emphasis Type="Italic">Melitaea aurelia</Emphasis>) has to consider habitat requirements of the immature stages,isolation, and patch area

We analysed the habitat preferences of adult stages and oviposition electivity of Melitaea aurelia in calcareous grasslands in the Diemel Valley (central Germany) to assess the key factors for successful management. Egg-laying and adult habitats of M. aurelia were more or less congruent. Oviposition electivity at the host plant (Plantago media) was best explained by a combination of host plant quantity and vegetation structure. Habitat quality, isolation and patch area explained 86% of the current patch occupancy of M. aurelia. With M. aurelia preferentially inhabiting transitional vegetation types, management requires a balance between abandonment and disturbance. Disturbances provide open soil that facilitates germination of the host plant Plantago media. On the other hand, immature and adult stages of M. aurelia perform best on calcareous grasslands with a high amount of host plants and low disturbance intensity. Traditional rough grazing regimes seem to be the most favourable tool for developing the necessary spatial and temporal heterogeneity in patches. The best results may be achieved by rotational grazing where only a subset of inhabited patches is grazed intensively each year. Our analysis of patch occupancy indicates that it would be desirable to restore patches in close proximity to occupied sites.     

Otolaryngology/Head and Neck Surgery: Intranasal Ethmoid Sinus Surgery, 1980 to 1990

The Scientific Board of the California Medical Association presents the following inventory of items of progress in otolaryngology/head and neck surgery. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and important clinical significance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, or scholars to stay abreast of these items of progress in otolaryngology/head and neck surgery that have recently achieved a substantial degree of authoritative acceptance, whether in their own field of special interest or another.The items of progress listed below were selected by the Advisory Panel to the Section on Otolaryngology/Head and Neck Surgery of the California Medical Association, and the summaries were prepared under its direction.     

Genetic diversity in the locally declining <Emphasis Type="Italic">Laserpitium prutenicum</Emphasis> L. and the more common <Emphasis Type="Italic">Selinum carvifolia</Emphasis> (L.) L.: a “silent goodbye”?

Evaluating the consequences of the decline of threatened species on their population genetic structure is crucial for establishing effective conservation strategies in the strongly fragmented landscapes of Central Europe. Laserpitium prutenicum is a bi- to perennial forb occurring in intermittently wet meadows and light oak forests throughout central to eastern and south-eastern Europe. During the past 70 years, the western limit of its distributional range retracted dramatically, the number of populations decreased and the remaining populations faced a considerable increase of fragmentation. To study the effects of this decline on the genetic diversity of L. prutenicum, we conducted an AFLP study on 20 populations from Germany, Poland and the Czech Republic. For comparison, we collected the same data on Selinum carvifolia, a taxonomically related and both ecologically and morphologically similar species, which is still more common in the study area. Both species showed similarly weak spatial genetic structuring and intermediate genetic diversities. We attribute this result to the loss of habitat being faster than the loss of genetic diversity in smaller and fragmented populations. Depending on the ecological characteristics of a species, even a gradual disappearance is not necessarily accompanied by any detectable effect at the population genetic level (“silent goodbye”). In the case of L. prutenicum, habitat preservation should be given priority over all other conservation measures.     

Phosphorylated EGFR Dimers Are Not Sufficient to Activate Ras

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