Chlorosome Proteins Studied by MALDI-TOF-MS: Topology of CsmA in Chlorobium tepidum

Chlorosomes, the light-harvesting apparatus of green bacteria, are a unique antenna system, in which pigments are organized in aggregates rather than associated with proteins. Isolated chlorosomes from the green sulphur bacterium Chlorobium tepidum contain 10 surface-exposed proteins. Treatment of chlorosomes from Chlorobium tepidum with protease caused changes in the spectral properties of bacteriochlorophyll c and digestion of chlorosome proteins. Using SDS-PAGE analysis, immunoblotting and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) we have investigated the topology of the 59-residue CsmA protein. Our results show that at the N-terminus, the only amino acid available for protease degradation is the methionine. At the C-terminus, amino acids can be removed by protease treatment to produce a residual protein containing at least the sequence between residues 2 and 38. These results indicate that the N-terminal portion of the CsmA protein, which is predicted to be mainly hydrophobic, is buried in the chlorosome envelope.     

Rapid change in adaptive performance from one generation to the next in <Emphasis Type="Italic">Picea abies</Emphasis>—Central European trees in a Nordic environment

Seedlings of open-pollinated Picea abies families from Norwegian and Central European parent trees standing at three sites in Norway were tested for timing of bud set at the end of the first growth season together with seedlings from control provenances producing seeds at their geographical origin. The parental origins were confirmed with a maternally inherited mitochondrial marker that distinguishes trees of the Northern European range from those of the Central European range. The seedlings from the families of Central European mother trees producing seeds in Norway had on average a bud set more similar to the families of local Norwegian origin producing seeds at the same site than the provenance of the same Central European origin. It is argued that the rapid change in this adaptive trait from one generation to the next can be explained by recent research results demonstrating that day length and temperature conditions during embryo formation and maturation can influence the phenotypic performance of seedlings in Norway spruce. This effect may influence the fitness of naturally regenerated plants produced in plantations of Central European trees in Norway.     

Symptoms of respiratory tract infection and associated care-seeking in subjects with and without obstructive lung disease; The Tromso Study: Tromso 6

ABSTRACT: BACKGROUND: Respiratory tract infections (RTIs) may be more severe in those with asthma or COPD and these patients are more frequently in need of health care. The aim of the study was to describe the frequency of RTI symptoms in a general adult population and how care-seeking is associated with the presence of obstructive lung disease. METHODS: Cross-sectional data including spirometry and self-reported chronic diseases were collected among middle-aged and elderly subjects in the Tromso population survey (Tromso 6). Self- reported RTI symptoms, consultations and antibiotic use were the main outcome variables. Possible predictors of RTI symptoms were evaluated by multivariable logistic regression. RESULTS: Of the 6414 subjects included, 798 (12.4 %) reported RTI symptoms in the previous week. RTI symptoms were reported less frequently by subjects aged 75 years or above, than by those younger than 55 years (OR 0.5). Winter season (OR 1.28), current smoking (OR 1.60), low self-rated health (OR 1.26) and moderate to severe bronchial obstruction (OR 1.51), were also statistically significant independent predictors of RTI symptoms, but these variables did not predict RTI symptoms that had started within the previous seven days. Among subjects with RTI symptoms, 5.1 % also reported a consultation with a doctor. In those with bronchial obstruction by spirometry, who did not report asthma or COPD, this frequency was 2.4 %. Antibiotic treatment was reported by 7.4 % of the participants, among whom one third had consulted a doctor. Antibiotics were taken more frequently when asthma or COPD was reported (13.7 %), but not in subjects with bronchial obstruction who did not report these diseases (7.2 %). CONCLUSIONS: RTI symptoms seldom led to consultation with a doctor and not even in subjects with obstructive lung disease. This was in particular the case in subject who did not know about their obstructive lung disease. Strategies for early diagnosis of COPD and providing health care to subjects with such disease cannot rely on their doctor visits due to respiratory symptoms.     

P2X1 receptor blockers reduce the number of circulating thrombocytes and the overall survival of urosepsis with haemolysin-producing Escherichia coli

Purinergic Signalling - Urosepsis is a severe condition often caused by Escherichia coli that spontaneously have ascended the urinary tract to the kidneys causing pyelonephritis and potentially...     

Additive inheritance of histone modifications in Arabidopsis thaliana intra-specific hybrids

Plant genomes are earmarked with defined patterns of chromatin marks. Little is known about the stability of these epigenomes when related, but distinct genomes are brought together by intra‐species hybridization. Arabidopsis thaliana accessions and their reciprocal hybrids were used as a model system to investigate the dynamics of histone modification patterns. The genome‐wide distribution of histone modifications H3K4me2 and H3K27me3 in the inbred parental accessions Col‐0, C24 and Cvi and their hybrid offspring was compared by chromatin immunoprecipitation in combination with genome tiling array hybridization. The analysis revealed that, in addition to DNA sequence polymorphisms, chromatin modification variations exist among accessions of A. thaliana. The range of these variations was higher for H3K27me3 (typically a repressive mark) than for H3K4me2 (typically an active mark). H3K4me2 and H3K27me3 were rather stable in response to intra‐species hybridization, with mainly additive inheritance in hybrid offspring. In conclusion, intra‐species hybridization does not result in gross changes to chromatin modifications.