Reproductive Competition in Colonies of the Ant Leptothorax gredleri

Colonies of the ant, Leptothorax (s. str.) gredleri may contain several inseminated female reproductives of which typically only one is laying eggs. Observations suggest that “functional monogyny” is caused by aggressive interactions among nestmate queens. Only the most dominant queen reproduces. Subordinate queens either leave the colony to found their own nests solitarily or by budding, or stay in the nest without reproducing, but may eventually replace the dominant queen. The interrelations of life history of L. gredleri, population structure and habitat characteristics are examined.     

Treatment of HeLa cells with bacterial water extracts inhibits Shigella flexneri invasion

Abstract Pathogenesis mediated by Shigella flexneri requires invasion of the gastrointestinal epithelium. It has been previously shown that HeLa cells challenged with S. flexneri show alterations in their phosphotyrosine-containing protein profile. In this report, we demonstrated that bacterial water extracts (WE) abrogated the invasion of HeLa cells by S. flexneri in a dose-dependent manner. A proteinaceous component of S. flexneri was shown to be responsible for this inhibitory activity. Proteins encoded on the 140-MDa plasmid were not responsible for the observed inhibition. WE from other Gram-negative bacteria also inhibited Shigella invasion of HeLa cells. HeLa cells pretreated with WE showed changes in the profile and the intensity of phosphotyrosine-containing protein bands. These data were consistent with a surface protein component in WE which initiated aberrant host cell signaling at the membrane which may account for the inhibition of bacterial entry.     

BBReader: A computer program for the combined use of the BioMagResBank and PDB databases

A computer program (BBReader) was developed which performs an inverse search in theBioMagResBank database. Given (cross) peak positions of a protein, the program searchesfor atoms with matching chemical shifts and suggests possible assignments for user-specifiedhomo- and heteronuclear one- to three-dimensional COSY- and NOESY-type experiments.It can handle 1H, 13C and 15N spectra. Distance information from PDB files can be utilizedfor filtering possible NOESY cross peak assignments.     

Spider biodiversity potential of an ungrazed and a grazed inland salt meadow in the National Park 'Neusiedler See-Seewinkel' (Austria): implications for management (Arachnida: Araneae)

To assess the biodiversity potential of an ungrazed and a grazed inland salt meadow in the Seewinkel (Eastern Austria), spider assemblages were recorded by pitfall trapping for 1 year. Both species assemblages consisted, to a large extent, of rare species of conservation interest. The species assemblage of the grazed site was dominated by Pardosa agrestis, but highly specific halotopobiontic species also occurred in higher numbers. Halotolerant species were also present in the ungrazed meadow, but their individual number was much lower. The species composition of this site reflects the more balanced microclimatical situation of the high sward. Comparison of the two assemblages with 207 other meadow spider assemblages of Central Europe shows a separated position, especially of the grazed site assemblage. High similarities with assemblages of meadows with a similar vegetation structure indicate a high importance of management. Considering the high proportion of rare species on both sites, the best management of the salt meadow and pan shores of the Seewinkel should combine areas of light grazing with ungrazed areas. However, the proportion of these parts and the intensity of grazing still remains to be determined by quantitative experiments.     

Transports of water,particulate and dissolved organic and inorganic matter between a salt marsh and the Ems-Dollard estuary,the Netherlands

Summary Transport processes were studied in a gully between a saltmarsh and an estuary. After storm tides, ebb currents in the gully reached high values. It is concluded that particulate matter (both obganic and inorganic) are imported into the marsh. Coarse organic debris is exported during storm tides, but this amount is low when compared with the primary production on the marsh. Exports are shown for dissolved organic carbon, ammonia, phosphate and silica, while nitrate and possibly nitrite are imported. Therefore, it seems warranted to conclude that the organic matter producedin situ and imported is mineralized in the marsh.     

Selective synthesis of depsipeptides by the immobilized multienzyme enniatin synthetase

Summary The multifunctional enzyme enniatin synthetase was immobilized by adsorption to propyl agarose. The immobilized multienzyme retained 45% of the activity of the free enzyme; an operational half-life of about 15 h was estimated. Selective synthesis of several different enniatin homologues was achieved with propyl agarose-bound enniatin synthetase. In addition to enniatin A, B, and C formation, a selective synthesis of non-naturally occurring depsipeptides, containing norvaline, norleucine, or -aminobutyric acid as sole amino acid moieties, was observed.     

Chloroherpeton thalassium gen. nov. et spec. nov., a non-filamentous,flexing and gliding green sulfur bacterium

A flexing and gliding green sulfur bacterium has been isolated from marine sources off the North East coast of the USA. Chloroherpeton thalassium is an obligate phototroph, and requires CO₂ and S^2- for growth; some organic acids can contribute to cell carbon, and N₂ may be fixed. The cells contain typical chlorosomes, and gas vesicles may be present. Bacteriochlorophyll c is the main light harvesting pigment, and a small quantity of bacteriochlorophyll a is also present. Over 80% of the carotenoid is -carotene. DNA base composition of the isolates ranges from 45.0–48.2 mol% G+C.In memory of R. Y. Stanier