Microbiological Synthesis of Fat: THE FORMATION OF FAT FROM SUCROSE

1. Forty-three strains of moulds, selected from ten species,were examined to ascertain their capabilities as producers offat, when grown in four different solutions of nutrient inorganicsalts together with sucrose. The three highest yields of feltwere given by Penicillium javanicum van Beyma, P. Soppi Zaleski,and Aspergillus nidulans Eidam, in that order. The fat contenton felt weight was maximal at 34·8 per cent, with P.Soppi, at 28·4 per cent. with Fusarium lini(1), and at25·8 per cent. with A. nidulans; on sugar utilized itwas maximal at 11·4 per cent. with P. Soppi, at 7·9per cent, with A. nidulans, and at 5·6 per cent. withF. lini(1). 2. Other moulds considered worthy of further trial were P. spinulosum,P. aurantiobrunneum, F. graminearum, A. flavus, F. oxysporum,A. clavatus, and P. oxalicum.     

Description of a new Eocene osteoglossid fish and additional information on †Singida jacksonoides Greenwood and Patterson, 1967 (Osteoglossomorpha), with an assessment of their phylogenetic relationships

A new genus and species of osteoglossomorph fish is described from the Eocene Mahenge site in north central Tanzania. The new species is sympatric with the previously described osteoglossomorph † Singida jacksonoides , but is easily distinguished from it by the presence in the new species of teeth on the jaws and entopterygoid. The new species shares characters with the Heterotidinae, such as the two arms of the preopercle being of similar length and the posterior end of the maxilla lying on the dentary, and other characters with the Osteoglossinae (including † Phareodus ), for example the enlarged pectoral fin ray and the shape of the opercular bone. New specimens of † S. jacksonoides also have been recovered from the site, providing more information on the osteology of this fish. The relationships of these two Mahenge osteoglossomorphs are assessed, with both fishes placed within the Osteoglossidae, but of uncertain position in the family. Addition of the new species to previous cladistic data sets, and the revised information for † S. jacksonoides , causes the subfamily Osteoglossinae to be nonmonophyletic.  © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 144 , 213–228.     

Using functional groups to investigate community response to environmental changes: two grassland case studies

Functional groups (FG) are an useful generalization to investigate environmental change effects on biotic communities. Assigning species to FGs is a contextual task and carries an arbitrary element, regardless of whether the grouping is obtained a priori or by sophisticated numerical methods. Using two grassland community case studies, we show that even simple FG allocation based on growth form, architecture and longevity (plants and mosses), or foraging characteristics (above-ground invertebrates) can be useful to increase our understanding of community processes. For example, the sensitivity of organisms to climate change increases with trophic rank and is higher in disturbed than in undisturbed communities. Complexity of interaction webs (in terms of web connectance), however, is larger in undisturbed than in disturbed communities. A significant and important relationship is likely to exist between anthropogenic disturbances, community complexity and the ecosystem effects of climate change. Trophic interactions may be disrupted much easier by climate changes in disturbed than in undisturbed communities where complexity may be buffering these effects.     

Variations among cell lines in the synthesis of sphingolipids in de novo and recycling pathways

There are several pathways for the incorporation of sugars into glycosphingolipids (GSL). Sugars can be added to ceramide that contains sphinganine (dihydrosphingosine) synthesized de novo (pathway 1), to ceramide synthesized from sphingoid bases produced by hydrolysis of sphingolipids (pathway 2), and into GSL recycling from the endosomal pathway through the Golgi (pathway 3). We reported previously the surprising observation that SW13 cells, a human adrenal carcinoma cell line, synthesize most of their GSL in pathway 2. We now present data on the synthesis of GSL in four additional cell lines. Approximately 90% of sugar incorporation took place in pathway 2, and 10% or less in pathway 1, in human foreskin fibroblasts and NB41A3 neuroblastoma cells. In contrast, approximately 50-90% of sugar incorporation took place in pathway 1 in C2C12 myoblasts. The C2C12 cells divide more rapidly and synthesize 10-14 times as much GSL as the other three cell lines. In C6 glioma cells, approximately 30% of sugar incorporation occurred in pathway 1 and 60% in pathway 2. There was no relation between the utilization of pathways for GSL and sphingomyelin synthesis in foreskin fibroblasts and C2C12 cells. In both cells pathways 1 and 2 each accounted for 50% of incorporation of choline into sphingomyelin. In five of the six cell lines that we have studied, most GSL synthesis takes place in pathway 2. We suggest that when the need for synthesis is relatively low, as in slowly dividing cells, GSL are synthesized predominantly from sphingoid bases salvaged from the hydrolytic pathway. When cells are dividing more rapidly, the need for increased synthesis is met by upregulating the de novo pathway.