Analysis of a 2,4,6-trichlorophenol-dehalogenating enrichment culture and isolation of the dehalogenating member Desulfitobacterium frappieri strain TCP-A

An anaerobic, 2,4,6-trichlorophenol ortho-dehalogenating mixed culture was enriched from sediment of the river Saale (Germany). Two isolated dechlorinating colonies (MK1 and MK2) consisted of rods of different lengths and thicknesses, indicating heterogeneity. Following subcultivation with thiosulfate as alternative electron acceptor and cocultivation with Clostridium celerecrescensT, the 2,4,6-trichlorophenol-dehalogenating bacterium Desulfitobacterium frappieri strain TCP-A was isolated and characterized regarding its taxonomic properties and the spectrum of chlorophenols that it dehalogenated. Four other bacterial strains were coenriched and identified as organisms with closest phylogenetic relatedness to the Clostridium type strains C. indolis, C. glycolicum, C. hydroxybenzoicum and C. sporosphaeroides (16S rDNA sequence identities of 99.5, 99.2, 94.4, and 93.5%, respectively). Amplified ribosomal DNA restriction analysis of the original dehalogenating cultures MK1 and MK2 (when not exposed to thiosulfate) confirmed the microbial heterogeneity and revealed the presence of two additional species related to the type strains of C. celerecrescens and Clostridium propionicum. Only one copy of the 16S rRNA genes of Desulfitobacterium frappieri in each of the clone libraries of MK1 and MK2 (containing 136 and 56 clones, respectively) was found by dot-blot hybridization, suggesting a relatively low number of the dehalogenating bacterium within the enrichment culture.     

Acute changes of myocardial creatine kinase gene expression under beta-adrenergic stimulation

Creatine kinase (CK) plays a crucial role in myocardial energy metabolism. Alterations in CK gene expression are found in hypertrophied and failing heart, but the mechanisms behind these changes are unclear. This study tests the hypothesis that increased adrenergic stimulation, which is observed in heart failure, induces changes of myocardial CK-activity, -isoenzyme distribution and -gene expression that are characteristic of the failing and hypertrophied heart. Isolated rat hearts were perfused (constant pressure of 80 mmHg) with red cell suspensions. Following a 20-min warm-up period, perfusion for 3 h with 10(-8) M (iso 3 h) or without (control 3 h) isoproterenol was started or experiments were immediately terminated (control 0 h). Left ventricular tissue was analyzed for total CK-activity, CK-isoenzyme distribution and, by use of quantitative RT-PCR, for B-CK, M-CK, mito-CK and GAPDH- (as internal standard) mRNA. After beta-adrenergic stimulation (iso 3 h) but not after control perfusion (control 3 h) a roughly threefold increase in B-CK mRNA levels and a decrease in M-CK mRNA levels by 18% was found. There were no significant differences among the three groups in total CK-activity and in distribution of CK-MM, CK-BB, CK-MB and mito-CK. Thus, beta-adrenergic stimulation induces a switch in CK gene expression from M-CK to B-CK, which is characteristic for the hypertrophied and failing heart. This may be interpreted as an adaptive mechanism making energy transduction via CK more efficient at times of increased metabolic demand.     

Identification of Yersinia enterocolitica within the genus Yersinia

In this report we describe a PCR strategy for the unambigous identification of biochemically presumptive typed Yersinia (Y.) enterocolitica. A total of 269 isolates belonging to ten species of the genus Yersinia were investigated. In a first PCR only isolates classified as Y. enterocolitica (n = 113) gave rise to a specific amplification resulting in a sensitivity and a specificity of 100%. By sequencing the 269 amplicons of a second pan-Yersinia PCR spanning a distinct 16S rRNA gene region, 20 different sequence clusters could be identified within the genus. By this, Y. enterocolitica isolates of American and European origin could be distinguished safely and already described sequence clusters of the species Y. frederiksenii were confirmed. New 16S rRNA gene sequence clusters were detected for the species Y. frederiksenii, Y. intermedia, Y. mollaretii, Y. aldovae, Y. kristensenii, and Y. rohdei.     

Bassoon,a Novel Zinc-finger CAG/Glutamine-repeat Protein Selectively Localized at the Active Zone of Presynaptic Nerve Terminals

The molecular architecture of the cytomatrix of presynaptic nerve terminals is poorly understood. Here we show that Bassoon, a novel protein of >400,000 M _r, is a new component of the presynaptic cytoskeleton. The murine bassoon gene maps to chromosome 9F. A comparison with the corresponding rat cDNA identified 10 exons within its protein-coding region. The Bassoon protein is predicted to contain two double-zinc fingers, several coiled-coil domains, and a stretch of polyglutamines (24 and 11 residues in rat and mouse, respectively). In some human proteins, e.g., Huntingtin, abnormal amplification of such poly-glutamine regions causes late-onset neurodegeneration. Bassoon is highly enriched in synaptic protein preparations. In cultured hippocampal neurons, Bassoon colocalizes with the synaptic vesicle protein synaptophysin and Piccolo, a presynaptic cytomatrix component. At the ultrastructural level, Bassoon is detected in axon terminals of hippocampal neurons where it is highly concentrated in the vicinity of the active zone. Immunogold labeling of synaptosomes revealed that Bassoon is associated with material interspersed between clear synaptic vesicles, and biochemical studies suggest a tight association with cytoskeletal structures. These data indicate that Bassoon is a strong candidate to be involved in cytomatrix organization at the site of neurotransmitter release.     

PRMT1 promotes the tumor suppressor function of p14ARF and is indicative for pancreatic cancer prognosis

The p14^ARF protein is a well‐known regulator of p53‐dependent and p53‐independent tumor‐suppressive activities. In unstressed cells, p14^ARF is predominantly sequestered in the nucleoli, bound to its nucleolar interaction partner NPM. Upon genotoxic stress, p14^ARF undergoes an immediate redistribution to the nucleo‐ and cytoplasm, where it promotes activation of cell cycle arrest and apoptosis. Here, we identify p14^ARF as a novel interaction partner and substrate of PRMT1 (protein arginine methyltransferase 1). PRMT1 methylates several arginine residues in the C‐terminal nuclear/nucleolar localization sequence (NLS/NoLS) of p14^ARF. In the absence of cellular stress, these arginines are crucial for nucleolar localization of p14^ARF. Genotoxic stress causes augmented interaction between PRMT1 and p14^ARF, accompanied by arginine methylation of p14^ARF. PRMT1‐dependent NLS/NoLS methylation promotes the release of p14^ARF from NPM and nucleolar sequestration, subsequently leading to p53‐independent apoptosis. This PRMT1‐p14^ARF cooperation is cancer‐relevant and indicative for PDAC (pancreatic ductal adenocarcinoma) prognosis and chemotherapy response of pancreatic tumor cells. Our data reveal that PRMT1‐mediated arginine methylation is an important trigger for p14^ARF’s stress‐induced tumor‐suppressive function.     

High-throughput screening for ionic liquids dissolving (ligno-)cellulose

The recalcitrance of lignocellulosic biomass poses a major challenge for its sustainable and cost-effective utilization. Therefore, an efficient pretreatment is decisive for processes based on lignocellulose. A green and energy-efficient pretreatment could be the dissolution of lignocellulose in ionic liquids. Several ionic liquids were identified earlier which are capable to dissolve (ligno-)cellulose. However, due to their multitude and high costs, a high-throughput screening on small scale is essential for the determination of the most efficient ionic liquid. In this contribution two high-throughput systems are presented based on extinction or scattered light measurements. Quasi-continuous dissolution profiles allow a direct comparison of up to 96 ionic liquids per experiment in terms of their dissolution kinetics. The screening results indicate that among the ionic liquids tested EMIM Ac is the most efficient for dissolving cellulose. Moreover, it was observed that AMIM Cl is the most effective ionic liquid for dissolving wood chips.     

A preliminary account of patterns of endemism in Namibia's Sperrgebiet – the succulent karoo

Aim This study investigated spatial patterns of endemism in the flora of Namibia's succulent karoo in order to generate information for conservation planning. Location The study area, the Sperrgebiet, comprises the majority of Namibia's portion of the succulent karoo biome which is the south‐west corner of the country. This is an arid area that has been off limits to public access, farming and tourism for nearly a century due to restrictions imposed by the diamond industry. Methods Based on existing distribution records, areas of high concentrations of endemic plants were identified using numbers of endemics and weighted endemics according to area of occupancy. The resolution of the available data was quarter degree squares (15‐min intervals of latitude and longitude grids). Results At the scale of this study straight numbers of endemics generated similar results to the endemics weighted according to area of occupancy, which gives sparsely distributed species a higher weighting. Based on the current distribution records, 17.7% (184 species) of the Sperrgebiet's spermatophyte flora is endemic. The ‘hotspots of endemism’ comprised from north to south: Lüderitz‐Kowisberge, Klinghardt Mountains, Aurusberge‐Heioab, Witpütz, Skorpion and Obib‐Schakalsberge. Taking also areas into account that stand out because of their high proportion of local endemics, this adds Grillental and the central coastal area from Pomona to Baker's Bay to the areas of importance for plant endemism. Main conclusions The Sperrgebiet's endemic flora is special in taxonomic composition in that it does not present a subset of the total flora of this area, but shows a remarkably high representation of the families Mesembryanthemaceae and Liliaceae (sensu lato). Compared with other arid areas, the level of endemism in the Sperrgebiet is high, but not compared with the succulent karoo in general or other hotspots in the succulent karoo biome, such as the Richtersveld. The proportion of local endemics (13.5%) is high compared with some endemism hotspots in southern Africa. Hotspots of plant endemism provide an important tool to contribute to conservation planning studies. This study also highlighted the importance of centralized data bases without which these analyses would not have been possible. Further plant collecting is required to fill presently data‐deficient areas and studies at a finer spatial resolution taking habitat requirements into account are needed to elucidate some of the factors contributing to plant endemism in this area.