Extraordinary features in the Chlamydomonas reinhardtii chloroplast genome: (1) rps2 as part of a large open reading frame; (2) a C. reinhardtii specific repeat sequence

AbstractWe have determined the DNA sequence of the 3574-bp chloroplast DNA fragment of Chlamydomonas reinhardtii formed by the overlap of BamHI fragment 3 and EcoRI fragment 5. This sequence encodes most of rps18 and orf570, an unidentified open reading frame that contains a 150 amino acid domain with high homology to the N-terminal part of 30 S ribosomal protein S2 of other chloroplast, cyanobacterial and bacterial genomes. Between these two sequences lies a highly repetitive sequence element of 500 bp, that is composed of multiple direct and inverted repeat sequences that occur in rearranged, but highly conserved form in at least 36 locations in the C. reinhardtii chloroplast genome. Among the conserved repeat sequences in the C. reinhardtii chloroplast genome we identified the borders of the inverted repeats near atpB and rps4. This might indicate that the conserved sequence elements are remainders of gene rearrangements in the chloroplast genome that occurred by relocations of the inverted repeats

Contribution of the Liquid Phase on Direct Current Interruption by a Forced Fluid Flow

The rising amount of medium voltage direct-current systems requires novel solutions for DC switching. The interruption of direct-currents is accomplished by enforcing a current zero, which can only be achieved when the arc voltage of the switching device raises above the grid voltage. On way to achieve this, is to force the arc into narrow channels by an imposed fluid flow. The increasing arc voltage than not only depends on increased cooling due to phase change but also on the mechanical elongation of the arc enforced by the fluid stream. Hence, the interaction of the fluid flow and the arc should be studied in more detail. For this, the switching characteristic of selected dielectric liquids are examined. Using a self developed setup, direct-current interruptions at a constant voltage of 10kV were carried out. Our results indicate, that the process of enforcing a current decay strongly depends on the mechanical resistance of the liquids to deform under the pressure of the electric arc

Protein synthesis by isolated chloroplasts of Chlamydomonas reinhardii

AbstractChloroplasts which have been isolated from the cell wall mutant cw15-2 of Chlamydomonas reinhardii are active in light-dependent, in organello protein synthesis. Certain characteristics of protein synthesis in this system were tested, such as time course of amino acid incorporation, sensitivities to Mg2+ as well as to specific inhibitors, and found to be typical of chloroplasts isolated from higher plants. The major products made were identified as the large subunit of ribulose-1,5-biphosphate carboxylase and the 32-kDa rapidly labelled membrane protein

Quantification of mRNA in Chloroplasts of Chlamydomonas reinhardii: Equal Distribution of mRNA for a Soluble and a Membrane Polypeptide in Stroma and Thylakoids

The relative contents of the mRNAs were analyzed for the 32 kDa herbicide-binding protein and for the large subunit of ribulose-l,5-bisphosphate carboxylase in the membrane fraction and in the soluble fraction of chloroplasts from Chlamydomonas reinhardii. The presence of mRNA for the two proteins in both subchloroplast fractions was demonstrated by in vitro translation of isolated RNA in the reticulocyte lysate. The relative amounts of the two mRNAs were measured by hybridizations with cloned chloroplast DNA probes at two stages of the cell cycle. Both mRNAs were distributed in the same ratio between membrane and soluble fractions, about 75% of both mRNAs being in the membrane and 25% in the soluble fraction. Therefore, in chloroplasts the accumulation of mRNAs on thylakoid membranes does not reflect the final localization of soluble and membrane protein

Arthroscopy or ultrasound in undergraduate anatomy education: a randomized cross-over controlled trial

Background: The exponential growth of image-based diagnostic and minimally invasive interventions requires a detailed three-dimensional anatomical knowledge and increases the demand towards the undergraduate anatomical curriculum. This randomized controlled trial investigates whether musculoskeletal ultrasound (MSUS) or arthroscopic methods can increase the anatomical knowledge uptake. Methods: Second-year medical students were randomly allocated to three groups. In addition to the compulsory dissection course, the ultrasound group (MSUS) was taught by eight, didactically and professionally trained, experienced student-teachers and the arthroscopy group (ASK) was taught by eight experienced physicians. The control group (CON) acquired the anatomical knowledge only via the dissection course. Exposure (MSUS and ASK) took place in two separate lessons (75 minutes each, shoulder and knee joint) and introduced standard scan planes using a 10-MHz ultrasound system as well as arthroscopy tutorials at a simulator combined with video tutorials. The theoretical anatomic learning outcomes were tested using a multiple-choice questionnaire (MCQ), and after cross-over an objective structured clinical examination (OSCE). Differences in student's perceptions were evaluated using Likert scale-based items. Results: The ASK-group (n = 70, age 23.4 (20--36) yrs.) performed moderately better in the anatomical MC exam in comparison to the MSUS-group (n = 84, age 24.2 (20--53) yrs.) and the CON-group (n = 88, 22.8 (20--33) yrs.; p = 0.019). After an additional arthroscopy teaching 1 % of students failed the MC exam, in contrast to 10 % in the MSUS- or CON-group, respectively. The benefit of the ASK module was limited to the shoulder area (p < 0.001). The final examination (OSCE) showed no significant differences between any of the groups with good overall performances. In the evaluation, the students certified the arthroscopic tutorial a greater advantage concerning anatomical skills with higher spatial imagination in comparison to the ultrasound tutorial (p = 0.002; p < 0.001). Conclusions: The additional implementation of arthroscopy tutorials to the dissection course during the undergraduate anatomy training is profitable and attractive to students with respect to complex joint anatomy. Simultaneous teaching of basic-skills in musculoskeletal ultrasound should be performed by medical experts, but seems to be inferior to the arthroscopic 2D-3D-transformation, and is regarded by students as more difficult to learn. Although arthroscopy and ultrasound teaching do not have a major effect on learning joint anatomy, they have the potency to raise the interest in surgery

Role of cancer stem cell markers ALDH1, BCL11B, BMI-1, and CD44 in the prognosis of advanced HNSCC

PURPOSE Cancer stem cells (CSCs) are held accountable for the progress of head and neck squamous cell carcinoma (HNSCC). In the presented study, the authors evaluated the prognostic value of CSC markers in two particular HNSCC cohorts. METHODS This two cohort study consisted of 85~patients with advanced stage HNSCC, treated with primary radio(chemo)therapy (pRCT), and 95~patients with HNSCC, treated with surgery and partially adjuvant radio(chemo)therapy. Overall survival (OS), disease-free survival (DFS), and disease-specific survival (DSS) were assessed. Samples were assessed for the expression of different molecular stem cell markers (ALDH1, BCL11B, BMI\hbox-1, and CD44). RESULTS In the pRCT cohort, none of the baseline patient and tumor features exhibited a~statistically significant relation with survival in either the cohort or the human papillomavirus (HPV)-stratified subcohorts. High expression of BMI\hbox-1 significantly decreased OS and DFS, while high expression of CD44 decreased all modes of survival. Multivariate analysis showed significant prognostic influence for all tested CSC markers, with high BMI\hbox-1 and CD44 decreasing survival (BMI-1: OS, DFS, DSS; CD44: OS, DFS) and high ALDH1 and BCL11B showing a~beneficial effect on survival (ALDH1: OS, DFS; BCL11B: OS, DSS). In the surgical cohort, classical prognosticators such as HPV status, R1 resection, and nodal status in HPV-negative HNSCC played a~significant role, but the tested CSC markers showed no significant effect on prognosis. CONCLUSION Although validation in independent cohorts is still needed, testing for CSC markers in patients with advanced or late stage HNSCC might be beneficial, especially if many comorbidities exist or disease is irresectable. The findings might guide the development and earlier use of targeted therapies in the future

Dose response of the 16p11.2 distal copy number variant on intracranial volume and basal ganglia.

Carriers of large recurrent copy number variants (CNVs) have a higher risk of developing neurodevelopmental disorders. The 16p11.2 distal CNV predisposes carriers to e.g., autism spectrum disorder and schizophrenia. We compared subcortical brain volumes of 12 16p11.2 distal deletion and 12 duplication carriers to 6882 non-carriers from the large-scale brain Magnetic Resonance Imaging collaboration, ENIGMA-CNV. After stringent CNV calling procedures, and standardized FreeSurfer image analysis, we found negative dose-response associations with copy number on intracranial volume and on regional caudate, pallidum and putamen volumes (β = -0.71 to -1.37; P &lt; 0.0005). In an independent sample, consistent results were obtained, with significant effects in the pallidum (β = -0.95, P = 0.0042). The two data sets combined showed significant negative dose-response for the accumbens, caudate, pallidum, putamen and ICV (P = 0.0032, 8.9 × 10-6, 1.7 × 10-9, 3.5 × 10-12 and 1.0 × 10-4, respectively). Full scale IQ was lower in both deletion and duplication carriers compared to non-carriers. This is the first brain MRI study of the impact of the 16p11.2 distal CNV, and we demonstrate a specific effect on subcortical brain structures, suggesting a neuropathological pattern underlying the neurodevelopmental syndromes

Genetic variation in CFH predicts phenytoin-induced maculopapular exanthema in European-descent patients

Objective To characterize, among European and Han Chinese populations, the genetic predictors of maculopapular exanthema (MPE), a cutaneous adverse drug reaction common to antiepileptic drugs. Methods We conducted a case-control genome-wide association study of autosomal genotypes, including Class I and II human leukocyte antigen (HLA) alleles, in 323 cases and 1,321 drug-tolerant controls from epilepsy cohorts of northern European and Han Chinese descent. Results from each cohort were meta-analyzed. Results We report an association between a rare variant in the complement factor H–related 4 (CFHR4) gene and phenytoin-induced MPE in Europeans (p = 4.5 × 10–11; odds ratio [95% confidence interval] 7 [3.2–16]). This variant is in complete linkage disequilibrium with a missense variant (N1050Y) in the complement factor H (CFH) gene. In addition, our results reinforce the association between HLA-A*31:01 and carbamazepine hypersensitivity. We did not identify significant genetic associations with MPE among Han Chinese patients. Conclusions The identification of genetic predictors of MPE in CFHR4 and CFH, members of the complement factor H–related protein family, suggest a new link between regulation of the complement system alternative pathway and phenytoin-induced hypersensitivity in European-ancestral patients