NMR investigations of the interaction between the azo-dye sunset yellow and Fluorophenol

The interaction of small molecules with larger noncovalent assemblies is important across a wide range of disciplines. Here, we apply two complementary NMR spectroscopic methods to investigate the interaction of various fluorophenol isomers with sunset yellow. This latter molecule is known to form noncovalent aggregates in isotropic solution, and form liquid crystals at high concentrations. We utilize the unique fluorine-19 nucleus of the fluorophenol as a reporter of the interactions via changes in both the observed chemical shift and diffusion coefficients. The data are interpreted in terms of the indefinite self-association model and simple modifications for the incorporation of a second species into an assembly. A change in association mode is tentatively assigned whereby the fluorophenol binds end-on with the sunset yellow aggregates at low concentration and inserts into the stacks at higher concentrations

Silencing of the Violaxanthin De-Epoxidase Gene in the Diatom Phaeodactylum tricornutum Reduces Diatoxanthin Synthesis and Non-Photochemical Quenching

Diatoms are a major group of primary producers ubiquitous in all aquatic ecosystems. To protect themselves from photooxidative damage in a fluctuating light climate potentially punctuated with regular excess light exposures, diatoms have developed several photoprotective mechanisms. The xanthophyll cycle (XC) dependent non-photochemical chlorophyll fluorescence quenching (NPQ) is one of the most important photoprotective processes that rapidly regulate photosynthesis in diatoms. NPQ depends on the conversion of diadinoxanthin (DD) into diatoxanthin (DT) by the violaxanthin de-epoxidase (VDE), also called DD de-epoxidase (DDE). To study the role of DDE in controlling NPQ, we generated transformants of P. tricornutum in which the gene (Vde/Dde) encoding for DDE was silenced. RNA interference was induced by genetic transformation of the cells with plasmids containing either short (198 bp) or long (523 bp) antisense (AS) fragments or, alternatively, with a plasmid mediating the expression of a self-complementary hairpin-like construct (inverted repeat, IR). The silencing approaches generated diatom transformants with a phenotype clearly distinguishable from wildtype (WT) cells, i.e. a lower degree as well as slower kinetics of both DD de-epoxidation and NPQ induction. Real-time PCR based quantification of Dde transcripts revealed differences in transcript levels between AS transformants and WT cells but also between AS and IR transformants, suggesting the possible presence of two different gene silencing mediating mechanisms. This was confirmed by the differential effect of the light intensity on the respective silencing efficiency of both types of transformants. The characterization of the transformants strengthened some of the specific features of the XC and NPQ and confirmed the most recent mechanistic model of the DT/NPQ relationship in diatoms

A Gene in the Process of Endosymbiotic Transfer

BACKGROUND: The endosymbiotic birth of organelles is accompanied by massive transfer of endosymbiont genes to the eukaryotic host nucleus. In the centric diatom Thalassiosira pseudonana the Psb28 protein is encoded in the plastid genome while a second version is nuclear-encoded and possesses a bipartite N-terminal presequence necessary to target the protein into the diatom complex plastid. Thus it can represent a gene captured during endosymbiotic gene transfer. METHODOLOGY/PRINCIPAL FINDINGS: To specify the origin of nuclear- and plastid-encoded Psb28 in T. pseudonana we have performed extensive phylogenetic analyses of both mentioned genes. We have also experimentally tested the intracellular location of the nuclear-encoded Psb28 protein (nuPsb28) through transformation of the diatom Phaeodactylum tricornutum with the gene in question fused to EYFP. CONCLUSIONS/SIGNIFICANCE: We show here that both versions of the psb28 gene in T. pseudonana are transcribed. We also provide experimental evidence for successful targeting of the nuPsb28 fused with EYFP to the diatom complex plastid. Extensive phylogenetic analyses demonstrate that nucleotide composition of the analyzed genes deeply influences the tree topology and that appropriate methods designed to deal with a compositional bias of the sequences and the long branch attraction artefact (LBA) need to be used to overcome this obstacle. We propose that nuclear psb28 in T. pseudonana is a duplicate of a plastid localized version, and that it has been transferred from its endosymbiont

Inter-Observer Agreement on Subjects' Race and Race-Informative Characteristics

Health and socioeconomic disparities tend to be experienced along racial and ethnic lines, but investigators are not sure how individuals are assigned to groups, or how consistent this process is. To address these issues, 1,919 orthodontic patient records were examined by at least two observers who estimated each individual's race and the characteristics that influenced each estimate. Agreement regarding race is high for African and European Americans, but not as high for Asian, Hispanic, and Native Americans. The indicator observers most often agreed upon as important in estimating group membership is name, especially for Asian and Hispanic Americans. The observers, who were almost all European American, most often agreed that skin color is an important indicator of race only when they also agreed the subject was European American. This suggests that in a diverse community, light skin color is associated with a particular group, while a range of darker shades can be associated with members of any other group. This research supports comparable studies showing that race estimations in medical records are likely reliable for African and European Americans, but are less so for other groups. Further, these results show that skin color is not consistently the primary indicator of an individual's race, but that other characteristics such as facial features add significant information

A Single Peroxisomal Targeting Signal Mediates Matrix Protein Import in Diatoms

Peroxisomes are single membrane bound compartments. They are thought to be present in almost all eukaryotic cells, although the bulk of our knowledge about peroxisomes has been generated from only a handful of model organisms. Peroxisomal matrix proteins are synthesized cytosolically and posttranslationally imported into the peroxisomal matrix. The import is generally thought to be mediated by two different targeting signals. These are respectively recognized by the two import receptor proteins Pex5 and Pex7, which facilitate transport across the peroxisomal membrane. Here, we show the first in vivo localization studies of peroxisomes in a representative organism of the ecologically relevant group of diatoms using fluorescence and transmission electron microscopy. By expression of various homologous and heterologous fusion proteins we demonstrate that targeting of Phaeodactylum tricornutum peroxisomal matrix proteins is mediated only by PTS1 targeting signals, also for proteins that are in other systems imported via a PTS2 mode of action. Additional in silico analyses suggest this surprising finding may also apply to further diatoms. Our data suggest that loss of the PTS2 peroxisomal import signal is not reserved to Caenorhabditis elegans as a single exception, but has also occurred in evolutionary divergent organisms. Obviously, targeting switching from PTS2 to PTS1 across different major eukaryotic groups might have occurred for different reasons. Thus, our findings question the widespread assumption that import of peroxisomal matrix proteins is generally mediated by two different targeting signals. Our results implicate that there apparently must have been an event causing the loss of one targeting signal even in the group of diatoms. Different possibilities are discussed that indicate multiple reasons for the detected targeting switching from PTS2 to PTS1

Risk Reducing Salpingectomy and Delayed Oophorectomy in high risk women: views of cancer geneticists, genetic counsellors and gynaecological oncologists in the UK

Risk-reducing-salpingectomy and Delayed-Oophorectomy (RRSDO) is being proposed as a two-staged approach in place of RRSO to reduce the risks associated with premature menopause in high-risk women. We report on the acceptability/attitude of UK health professionals towards RRSDO. An anonymised web-based survey was sent to UK Cancer Genetics Group (CGG) and British Gynaecological Cancer Society (BGCS) members to assess attitudes towards RRSDO. Baseline characteristics were described using descriptive statistics. A Chi square test was used to compare categorical, Kendal-tau-b test for ordinal and Mann–Whitney test for continuous variables between two groups. 173/708 (24.4 %) of invitees responded. 71 % respondents (CGG = 57 %/BGCS = 83 %, p = 0.005) agreed with the tubal hypothesis for OC, 55 % (CGG = 42 %/BGCS = 66 %, p = 0.003) had heard of RRSDO and 48 % (CGG = 46 %/BGCS = 50 %) felt evidence was not currently strong enough for introduction into clinical practice. However, 60 % respondents’ (CGG = 48 %/BGCS = 71 %, p = 0.009) favoured offering RRSDO to high-risk women declining RRSO, 77 % only supported RRSDO within a clinical trial (CGG = 78 %/BGCS = 76 %) and 81 % (CGG = 76 %/BGCS = 86 %) advocated a UK-wide registry. Vasomotor symptoms (72 %), impact on sexual function (63 %), osteoporosis (59 %), hormonal-therapy (55 %) and subfertility (48 %) related to premature menopause influenced their choice of RRSDO. Potential barriers to offering the two-stage procedure included lack of data on precise level of benefit (83 %), increased surgical morbidity (79 %), loss of breast cancer risk reduction associated with oophorectomy (68 %), need for long-term follow-up (61 %) and a proportion not undergoing DO (66 %). There were variations in perception between BGCS/CGG members which are probably attributable to differences in clinical focus/expertise between these two groups. Despite concerns, there is reasonable support amongst UK clinicians to offering RRSDO to premenopausal high-risk women wishing to avoid RRSO, within a prospective clinical trial.This work has not been directly funded by any commercial organisation, or charity

Computerized clinical decision support systems for acute care management: A decision-maker-researcher partnership systematic review of effects on process of care and patient outcomes

<p>Abstract</p> <p>Background</p> <p>Acute medical care often demands timely, accurate decisions in complex situations. Computerized clinical decision support systems (CCDSSs) have many features that could help. However, as for any medical intervention, claims that CCDSSs improve care processes and patient outcomes need to be rigorously assessed. The objective of this review was to systematically review the effects of CCDSSs on process of care and patient outcomes for acute medical care.</p> <p>Methods</p> <p>We conducted a decision-maker-researcher partnership systematic review. MEDLINE, EMBASE, Evidence-Based Medicine Reviews databases (Cochrane Database of Systematic Reviews, DARE, ACP Journal Club, and others), and the Inspec bibliographic database were searched to January 2010, in all languages, for randomized controlled trials (RCTs) of CCDSSs in all clinical areas. We included RCTs that evaluated the effect on process of care or patient outcomes of a CCDSS used for acute medical care compared with care provided without a CCDSS. A study was considered to have a positive effect (<it>i.e.</it>, CCDSS showed improvement) if at least 50% of the relevant study outcomes were statistically significantly positive.</p> <p>Results</p> <p>Thirty-six studies met our inclusion criteria for acute medical care. The CCDSS improved process of care in 63% (22/35) of studies, including 64% (9/14) of medication dosing assistants, 82% (9/11) of management assistants using alerts/reminders, 38% (3/8) of management assistants using guidelines/algorithms, and 67% (2/3) of diagnostic assistants. Twenty studies evaluated patient outcomes, of which three (15%) reported improvements, all of which were medication dosing assistants.</p> <p>Conclusion</p> <p>The majority of CCDSSs demonstrated improvements in process of care, but patient outcomes were less likely to be evaluated and far less likely to show positive results.</p

Identifying metabolic pathways for production of extracellular polymeric substances by the diatom Fragilariopsis cylindrus inhabiting sea ice

Diatoms are significant primary producers in sea ice, an ephemeral habitat with steep vertical gradients of temperature and salinity characterizing the ice matrix environment. To cope with the variable and challenging conditions, sea ice diatoms produce polysaccharide-rich extracellular polymeric substances (EPS) that play important roles in adhesion, cell protection, ligand binding and as organic carbon sources. Significant differences in EPS concentrations and chemical composition corresponding to temperature and salinity gradients were present in sea ice from the Weddell Sea and Eastern Antarctic regions of the Southern Ocean. To reconstruct the first metabolic pathway for EPS production in diatoms, we exposed Fragilariopsis cylindrus, a key bi-polar diatom species, to simulated sea ice formation. Transcriptome profiling under varying conditions of EPS production identified a significant number of genes and divergent alleles. Their complex differential expression patterns under simulated sea ice formation was aligned with physiological and biochemical properties of the cells, and with field measurements of sea ice EPS characteristics. Thus, the molecular complexity of the EPS pathway suggests metabolic plasticity in F. cylindrus is required to cope with the challenging conditions of the highly variable and extreme sea ice habitat

Do electronic health records affect the patient-psychiatrist relationship? A before & after study of psychiatric outpatients

<p>Abstract</p> <p>Background</p> <p>A growing body of literature shows that patients accept the use of computers in clinical care. Nonetheless, studies have shown that computers unequivocally change both verbal and non-verbal communication style and increase patients' concerns about the privacy of their records. We found no studies which evaluated the use of Electronic Health Records (EHRs) specifically on psychiatric patient satisfaction, nor any that took place exclusively in a psychiatric treatment setting. Due to the special reliance on communication for psychiatric diagnosis and evaluation, and the emphasis on confidentiality of psychiatric records, the results of previous studies may not apply equally to psychiatric patients.</p> <p>Method</p> <p>We examined the association between EHR use and changes to the patient-psychiatrist relationship. A patient satisfaction survey was administered to psychiatric patient volunteers prior to and following implementation of an EHR. All subjects were adult outpatients with chronic mental illness.</p> <p>Results</p> <p>Survey responses were grouped into categories of "Overall," "Technical," "Interpersonal," "Communication & Education,," "Time," "Confidentiality," "Anxiety," and "Computer Use." Multiple, unpaired, two-tailed t-tests comparing pre- and post-implementation groups showed no significant differences (at the 0.05 level) to any questionnaire category for all subjects combined or when subjects were stratified by primary diagnosis category.</p> <p>Conclusions</p> <p>While many barriers to the adoption of electronic health records do exist, concerns about disruption to the patient-psychiatrist relationship need not be a prominent focus. Attention to communication style, interpersonal manner, and computer proficiency may help maintain the quality of the patient-psychiatrist relationship following EHR implementation.</p