Integration of ultrasonography training into undergraduate medical education: catch up with professional needs.

Objective: Ultrasonography (US) has become the first-line imaging modality even for physicians who are not imaging specialists. The progress has not yet been sufficiently considered in medical education. The aim was to develop a curriculum that integrates US as a compulsory part into medical education directly from the start, to build up professional competencies toward residency.

PJplus - a project improving practical training during the final year of medical education.

Background: Practical training on the patient is crucial in medical students' last year education - the so-called practical year (PJ) in Germany. Due to difficulties in combining student training with the everyday tasks on ward, it is often criticised as not sufficient for a good preparation for later practical work. The Medical Faculty of the University of Jena therefore designed a project called "PJplus".

Reformed conventional curriculum promoting the professional interest orientation of students of medicine: JENOS.

In the last ten years, the medical faculty at Friedrich Schiller University Jena has reformed its traditional curriculum for human medicine. The reformed JENa professional interest-Oriented Studies (JEnaer Neigungs-Orientiertes Studium, JENOS) - with the objective to facilitate career entry through a professional interest-oriented practical approach - emerged due to the stipulation of cost neutrality. Report on the process sequence of JENOS from the reform idea to implementation: the initial processes, the development and assessment process with accompanying dialogue and dispute of the reform process within the faculty shall be discussed.

Biofilm formation of mucosa-associated methanoarchaeal strains.

Although in nature most microorganisms are known to occur predominantly in consortia or biofilms, data on archaeal biofilm formation are in general scarce. Here, the ability of three methanoarchaeal strains, Methanobrevibacter smithii and Methanosphaera stadtmanae, which form part of the human gut microbiota, and the Methanosarcina mazei strain Gö1 to grow on different surfaces and form biofilms was investigated. All three strains adhered to the substrate mica and grew predominantly as bilayers on its surface as demonstrated by confocal laser scanning microscopy analyses, though the formation of multi-layered biofilms of Methanosphaera stadtmanae and Methanobrevibacter smithii was observed as well.

The transcriptional activator NrpA is crucial for inducing nitrogen fixation in Methanosarcina mazei Gö1 under nitrogen-limited conditions.

With the aim of unraveling their potential involvement in the regulation of nitrogen metabolism in Methanosarcina mazei strain Gö1, we characterized five genes that are differentially transcribed in response to changing nitrogen availability and encoding putative transcriptional regulators. Study of the respective mutant strains under nitrogen-limited conditions revealed a growth delay for M. mazei MM0444::pac and MM1708::pac, and strongly reduced diazotrophic growth for MM0872::pac, whereas the absence of MM2441 or MM2525 did not affect growth behaviour.

Regulatory RNAs in archaea: first target identification in Methanoarchaea.

sRNAs (small non-coding RNAs) representing important players in many cellular and regulatory processes have been identified in all three domains of life. In Eukarya and Bacteria, functions have been assigned for many sRNAs, whereas the sRNA populations in Archaea are considerably less well characterized. Recent analyses on a genome-wide scale particularly using high-throughput sequencing techniques demonstrated the presence of high numbers of sRNA candidates in several archaea.

Establishing a markerless genetic exchange system for Methanosarcina mazei strain Gö1 for constructing chromosomal mutants of small RNA genes.

A markerless genetic exchange system was successfully established in Methanosarcina mazei strain Gö1 using the hpt gene coding for hypoxanthine phosphoribosyltransferase. First, a chromosomal deletion mutant of the hpt gene was generated conferring resistance to the purine analog 8-aza-2,6-diaminopurine (8-ADP). The nonreplicating allelic exchange vector (pRS345) carrying the pac-resistance cassette for direct selection of chromosomal integration, and the hpt gene for counterselection was introduced into this strain.

NrpRII mediates contacts between NrpRI and general transcription factors in the archaeon Methanosarcina mazei Gö1.

We report here on the formation of a complex between the two NrpR homologs present in Methanosarcina mazei Gö1 and their binding properties to the nifH and glnK(1) promoters. Reciprocal co-chromatography demonstrated that NrpRI forms stable complexes with NrpRII (at an NrpRI : NrpRII molar ratio of ∼ 1 : 3), which are not affected by 2-oxoglutarate. Promoter-binding, analyses using DNA-affinity chromatography and electrophoretic gel mobility shift assays, verified that NrpRII is not able to bind to either the nifH promoter or the glnK(1) promoter except when in complex with NrpRI.

Deep sequencing analysis of the Methanosarcina mazei Gö1 transcriptome in response to nitrogen availability.

Methanosarcina mazei and related mesophilic archaea are the only organisms fermenting acetate, methylamines, and methanol to methane and carbon dioxide, contributing significantly to greenhouse gas production. The biochemistry of these metabolic processes is well studied, and genome sequences are available, yet little is known about the overall transcriptional organization and the noncoding regions representing 25% of the 4.01-Mb genome of M.

Insights into the NrpR regulon in Methanosarcina mazei Gö1.

The methanogenic archaeon Methanosarcina mazei strain Gö1 contains two homologues of NrpR, the transcriptional repressor of nitrogen assimilation genes recently discovered and characterized in Methanococcus maripaludis. Insertion of a puromycin-resistance conferring cassette into MM1085 encoding a single NrpR domain with an N-terminal helix-turn-helix domain (NrpRI) lead to a significant reduction of the lag-phase after a shift from nitrogen sufficiency to nitrogen limitation. Consistent with this finding, loss of NrpRI resulted in significantly increased transcript levels of genes involved in nitrogen fixation or nitrogen assimilation though growing under nitrogen sufficiency as demonstrated by quantitative reverse transcriptional PCR analysis.

Deletion of the archaeal histone in Methanosarcina mazei Gö1 results in reduced growth and genomic transcription.

HMm is the only archaeal histone in Methanosarcina mazei Göl and recombinant HMm, synthesized by expression of MM1825 in Escherichia coli, has been purified and confirmed to have the DNA binding and compaction properties characteristic of an archaeal histone. Insertion of a puromycin resistance conferring cassette (pac) into MM1825 was not lethal but resulted in mutants (M. mazei MM1825::pac) that have impaired ability to grow on methanol and trimethylamine.

Global transcriptional analysis of Methanosarcina mazei strain Gö1 under different nitrogen availabilities.

Certain archaeal species can fix molecular nitrogen under nitrogen limiting conditions although little is known about this process at either the genetic or molecular level. To address this on a genome-wide scale, transcriptional analysis was performed on the model methanogen Methanosarcina mazei strain Gö1 using DNA-microarrays. The genomic expression patterns for cells grown under nitrogen fixing conditions versus nitrogen sufficiency (10 mM ammonium) revealed that approximately 5% of all genes are differentially expressed.

Effects of nitrogen and carbon sources on transcription of soluble methyltransferases in Methanosarcina mazei strain Go1.

The methanogenic archaeon Methanosarcina mazei strain Gö1 uses versatile carbon sources and is able to fix molecular nitrogen with methanol as carbon and energy sources. Here, we demonstrate that when growing on trimethylamine (TMA), nitrogen fixation does not occur, indicating that ammonium released during TMA degradation is sufficient to serve as a nitrogen source and represses nif gene induction. We further report on the transcriptional regulation of soluble methyltransferases, which catalyze the initial step of methylamine consumption by methanogenesis, in response to different carbon and nitrogen sources.

Development of genetic methods and construction of a chromosomal glnK1 mutant in Methanosarcina mazei strain Gö1.

The methanogenic archaeon Methanosarcina mazei strain Gö1 has so far proven to be genetically intractable due to its low plating efficiency on solid medium and the lack of an effective transformation method. Here, we report the first significant improvement in plating efficiency (up to 10%), which was achieved by (1) selecting for a spontaneous mutant of M. mazei that shows significantly higher resistance to mechanical stress during spreading an agar plates, and (2) plating the cells in 0.

Functional organization of a single nif cluster in the mesophilic archaeon Methanosarcina mazei strain Gö1.

The mesophilic methanogenic archaeon Methanosarcina mazei strain Gö1 is able to utilize molecular nitrogen (N2) as its sole nitrogen source. We have identified and characterized a single nitrogen fixation (nif) gene cluster in M. mazei Gö1 with an approximate length of 9 kbp.

Unique mechanistic features of post-translational regulation of glutamine synthetase activity in Methanosarcina mazei strain Gö1 in response to nitrogen availability.

PII-like signal transduction proteins are found in all three domains of life and have been shown to play key roles in the control of bacterial nitrogen assimilation. This communication reports the first target protein of an archaeal PII-like protein, representing a novel PII receptor. The GlnK(1) protein of the methanogenic archaeon Methanosarcina mazei strain Go1 interacts and forms stable complexes with glutamine synthetase (GlnA(1)).

Characterization of GlnK1 from Methanosarcina mazei strain Gö1: complementation of an Escherichia coli glnK mutant strain by GlnK1.

Trimeric PII-like signal proteins are known to be involved in bacterial regulation of ammonium assimilation and nitrogen fixation. We report here the first biochemical characterization of an archaeal GlnK protein from the diazotrophic methanogenic archaeon Methanosarcina mazei strain Gö1 and show that M. mazei GlnK1 is able to functionally complement an Escherichia coli glnK mutant for growth on arginine.