Interaction network of the ribosome assembly machinery from a eukaryotic thermophile

Ribosome biogenesis in eukaryotic cells is a highly dynamic and complex process innately linked to cell proliferation. The assembly of ribosomes is driven by a myriad of biogenesis factors that shape pre‐ribosomal particles by processing and folding the ribosomal RNA and incorporating ribosomal proteins. Biochemical approaches allowed the isolation and characterization of pre‐ribosomal particles from Saccharomyces cerevisiae, which lead to a spatiotemporal map of biogenesis intermediates along the path from the nucleolus to the cytoplasm. Here, we cloned almost the entire set (～180) of ribosome biogenesis factors from the thermophilic fungus Chaetomium thermophilum in order to perform an in‐depth analysis of their protein–protein interaction network as well as exploring the suitability of these thermostable proteins for structural studies. First, we performed a systematic screen, testing about 80 factors for crystallization and structure determination. Next, we performed a yeast 2‐hybrid analysis and tested about 32,000 binary combinations, which identified more than 1000 protein–protein contacts between the thermophilic ribosome assembly factors. To exemplary verify several of these interactions, we performed biochemical reconstitution with the focus on the interaction network between 90S pre‐ribosome factors forming the ctUTP‐A and ctUTP‐B modules, and the Brix‐domain containing assembly factors of the pre‐60S subunit. Our work provides a rich resource for biochemical reconstitution and structural analyses of the conserved ribosome assembly machinery from a eukaryotic thermophile.     

Acute phase protein haptoglobin in blood plasma samples of harbour seals (Phoca vitulina) of the Wadden Sea and of the isle Helgoland

Haptoglobin (Hp) which is synthesized in response to infection, inflammation, trauma or toxicological damage is known as a major acute phase protein in numerous species. Quantification of the circulating concentration of this protein can provide an objective measure of the health status, but there is a lack of investigations on harbour seals. We investigated the Hp concentration in samples of 123 seals (Phoca vitulina) from the German and Danish Wadden Sea to study physiological ranges of Hp levels. Hp levels between 2002, the end of the phocine distemper virus epidemic (PDV), and 2007 were considered, and Hp concentrations between animals of different sex, ages as well as living areas were compared. Furthermore, as a case study, six animals from the open sea isle Helgoland were investigated in 2006. Influences on the health status of the seal population e.g. the PDV epidemic were reflected by increased Hp levels in North Sea seals in 2002. The results of the Wadden Sea seals showed no significant age-, sex-, or geographical area-related differences. Interestingly, for the seals of the open sea isle Helgoland higher Hp values were measured compared to the Wadden Sea seals. The present study demonstrates that Hp can be used as a diagnostic tool to monitor the health status of harbour seals.     

Evaluation of Selected Membrane Filtration and Most Probable Number Methods for the Enumeration of Faecal Coliforms,Escherichia coli and Enterococci in Environmental Waters

Selected methods recommended in national and international water quality guidelines were compared in tests on environmental waters with different levels of faecal pollution. The following methods yielded no statistically significant differences in counts of faecal coliforms and Escherichia coli in raw sewage, semi-treated effluent, polluted urban run-off and stored potable water: Membrane filtration (MF) using MFc Agar or Chromocult Coliform Agar containing X-glucuronide, or a miniaturised microtitre-plate Most Probable Number (MPN) assay using a liquid growth medium containing chromogenic 4-methyl-umbelliferyl--D-glucuronide. Significant differences were, however, found between the Chromocult and the other methods for unpolluted river water. Counts of faecal enterococci in raw sewage, semi-treated effluent and polluted urban run-off, obtained by the following methods did not differ significantly: MF using M-Enterococcus Agar, Bile-Esculin Agar or Enterococcus Selective Agar, or a microtitre-plate MPN method with a liquid growth medium containing chromogenic 4-methyl-umbelliferyl--D-glucoside. Significant differences were, however, found between the MPN and the other methods for unpolluted river water and stored potable water. MF using Chromocult Coliform Agar had useful benefits for the simultaneous enumeration of coliforms and E coli. However, in view of cost and practical considerations, MF using MFc Agar or M-Enterococcus Agar proved the methods of choice for respectively enumerating faecal coliforms and E coli, or faecal enterococci, in analyses for general water quality surveillance purposes.     

Inheritance of Factors Affecting Floral Primordia Initiation in Cestrum; Hybrids of C. elegans and C. nocturnum

Photoperiod patterns of hybrids of Cestrum elegans (Brongn.) Schlect., a day neutral plant, and C. nocturnum L., a long-short day and long day plant, were investigated. Plants of the F₁ generation, F₂ generation, and backcrosses to each parent were tested on short day, long day, continuous light, long-short day and short-long day for floral primordia initiation. The data recorded suggest 2 independent genes or gene groups controlling floral primordia initiation in C. nocturnum, a single dominant gene that is activated by long-short day treatment and a recessive gene or genes responding to long day treatment. Further, these data suggest that the day neutral condition in C. elegans is the result of the series of independent genes or gene groups that respond to various photoperiods, the combination of these genes resulting in floral primordia initiation on all photoperiods.     

Sleep patterns afted graded exercise.

The effects of six graded and measured exercise activities on sleep patterns were investigated in two healthy young men. Electrophysiological recording were made continuously throughout the night to distinguish sleep states. This experiment was designed to test the hypothesis of a relation between physical activity and slow-wave sleep (SWS: stages 3 and 4 of non-REM sleep). A progressive increase in SWS over the whole-night sleep record was found with progressively increasing physical fatigue. A fall in rapid-eye-movement (REM) sleep and at higher exercise levels, of stage 2 sleep, was found. The results support the hypothesis that SWS is involved in the recovery process from fatigue.