Human neuropilin-1 and neuropilin-2 map to 10p12 and 2q34, respectively.
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Chromosomes, Human, Pair 10↗
Biomedical subjects
M Rossignol
Publications and source records attributed to M Rossignol.
Reconstitution of an electrogenic auxin transport activity mediated by Arabidopsis thaliana plasma membrane proteins.
Plasma membrane proteins from Arabidopsis thaliana leaves were reconstituted into proteoliposomes and a K+ diffusion potential was generated. The resulting ionic fluxes, determined in the presence of the plant hormone auxin (indole-3 acetic acid), showed an additional electrogenic and saturable component, with a K(M) of 6 microM. This flux was neither detected in liposomes in the presence of indole-3 acetic acid, nor in proteoliposomes in the presence of an inactive auxin analog and was completely inhibited by 3 microM naphtylphthalamic acid, a specific inhibitor of the auxin efflux carrier. The efficiency of the reconstituted carrier and the mechanism of its regulation by naphtylphthalamic acid are discussed.
Arabidopsis↗
Cloning and characterization of a maize cytochrome-b5 reductase with Fe3+-chelate reduction capability.
We previously purified an NADH-dependent Fe3+-chelate reductase (NFR) from maize roots with biochemical features of a cytochrome-b5 reductase (b5R) [Sparla, Bagnaresi, Scagliarini and Trost (1997) FEBS Lett. 414, 571-575]. We have now cloned a maize root cDNA that, on the basis of sequence information, calculated parameters and functional assay, codes for NFR. Maize NFR has 66% and 65% similarity to mammal and yeast b5R respectively. It has a deduced molecular mass of 31.17 kDa and a pI of 8.53. An uncharged region is observed at its N-terminus but no myristoylation consensus site is present. Taken together, these results, coupled with previous biochemical evidence, prove that NFR belongs to the b5R class and document b5R from a plant at the molecular level for the first time. We have also identified a putative Arabidopsis thaliana NFR gene. Its organization (nine exons) closely resembles mammalian b5Rs. Several NFR isoforms are expected to exist in maize. They are probably not produced by alternative translational mechanisms as occur in mammals, because of specific constraints observed in the maize NFR cDNA sequence. In contrast with yeast and mammals, tissue-specific and various subcellular localizations of maize b5R isoforms could result from differential expression of the various members of a multigene family. The first molecular characterization of a plant b5R indicates an overall remarkable evolutionary conservation for these versatile reductase systems. In addition, the well-characterized Fe3+-chelate reduction capabilities of NFR, in addition to known Fe3+-haemoglobin reduction roles for mammal b5R isoforms, suggest further and more generalized roles for the b5R class in endocellular iron reduction.
Amino Acid Sequence↗
Proteomics for genetic and physiological studies in plants.
Proteomics is becoming a necessity in plant biology, as it is in medicine, zoology and microbiology, for deciphering the function and role of the genes that are or will be sequenced. In this review we focus on the various, mainly genetic, applications of the proteomic tools that have been developed in recent years: characterization of individuals or lines, estimation of genetic variability within and between populations, establishment of genetic distances that can be used in phylogenetic studies, characterization of mutants and localization of the genes encoding the revealed proteins. Improvements in specifically devoted software have permitted precise quantification of the variation in amounts of proteins, leading to the concept of "protein quantity loci" which, combined with the "quantitative trait loci" approach, results in testable hypotheses regarding the role of "candidate proteins" in the metabolism or phenotype under study. This new development is exemplified by the reaction of plants to drought, a trait of major agronomic interest. The accumulation of data regarding genomic and cDNA sequencing will be connected to the protein databases currently developed in plants.
Chromosome Mapping↗
What triggers senescence in Podospora anserina?
Senescence of Podospora anserina is triggered by a cytoplasmic and infectious factor (the determinant of senescence) and is always correlated with mitochondrial DNA modifications, especially with the accumulation of small circular subgenomic DNA molecules, the senDNAs. Several observations have suggested that the senDNAs could be the cytoplasmic and infectious determinant. However, we show here (1) that senDNA molecules can be transferred to a young culture without the cotransmission of the determinant of senescence and (2) that the determinant of senescence does not segregate as a mitochondrial DNA mutation. Overall, our data strongly argue that amplification of senDNA molecules in the mitochondria is not an intrinsic property of these small DNA molecules. They question the nature of the actual determinant of senescence.
Aging↗
Large scale characterization of plant plasma membrane proteins.
After a brief review of the strategies used to date to identify systematically plasma membrane (PM) proteins, emphasis was given to the proteomic approach of PM proteins from the model plant Arabidopsis thaliana. Comparative analysis of two-dimensional gels from PM and cytosolic fractions was used to assess the cellular origin of proteins found in PM fraction. The classification obtained was confirmed by protein sequencing that showed, in addition, that most analyzed proteins were peripheral proteins. A large proportion of these appeared to correspond to PM-constitutive proteins that were present in the PM from different plant organs, but were not uniquely located at the PM depending on the organ. In addition, the presence of organ-specific sets of PM-specific proteins was also demonstrated. Additional procedures were developed to identify integral PM proteins. The combined use of PM washes with alkaline carbonate buffer or Triton X-100/KBr, and of a new detergent to solubilize protein, resulted in improved recovery of hydrophobic proteins on gels. Results are discussed in terms of construction of comprehensive proteomes for PM and other membranes and organelles.
Animals↗
Propagation of a novel cytoplasmic, infectious and deleterious determinant is controlled by translational accuracy in Podospora anserina.
Some mutant strains of the filamentous fungus Podospora anserina spontaneously present a growth impairment, which has been called Crippled Growth (CG). CG is caused by a cytoplasmic and infectious factor, C. C is efficiently transmitted during mitosis but is not transmitted to the progeny after sexual crosses. C is induced by stationary phase and cured by various means, most of which stress the cells. Translational accuracy is shown to tightly regulate the propagation of C during the active growth period, because its propagation in dividing hyphae is restricted to cells that display an increased translational accuracy. However, induction of C in stationary phase proceeds independently from the translational accuracy status of the strain. CG does not seem to be accompanied by mitochondrial DNA modifications, although C activates the action of the Determinant of Senescence, another cytoplasmic and infectious element, which causes a disorganization of the mitochondrial genome. In addition, presence of C drastically modifies the spectrum of the mitochondrial DNA rearrangements in AS6-5 mat- cultures during Senescence. C seems to belong to the growing list of unconventional genetic elements. The biological significance of such elements is discussed.
Ascomycota↗
Some psychological and physical consequences in middle-aged adults of underfunded institutional care in childhood.
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Adolescent↗
Adolescent growth is not associated with changes in flexibility.
OBJECTIVE: To determine whether adolescent growth is associated with a decrease in flexibility. DESIGN: Longitudinal cohort study of urban high school students. MAIN OUTCOME MEASURES: Flexibility of hamstring muscles (popliteal angle), quadriceps muscles (quadriceps angle), lumbar extensor muscles (Schober test), and combined lower extremity-trunk muscles (Sit and Reach test). RESULTS: There was no relation between growth and changes in flexibility for the lumbar flexor muscles, hamstring muscles, or muscles involved in the Sit and Reach test. Although there was a slight decrease in flexibility of the quadriceps muscle with increases in growth, the very low r2adj value (0.01-0.06) strongly suggests that growth plays only a small role in determining the flexibility of individuals. CONCLUSION: These results strongly suggest that growth is not a cause of decreased flexibility during the peripubescent period.
Adolescent↗
Cloning of the V-ATPase subunit G in plant: functional expression and sub-cellular localization.
A 13-kDa tobacco plasma membrane protein was isolated from two-dimensional electrophoresis gels. After microsequencing, RT-PCR techniques and cDNA library screening allowed for the cloning of two cDNAs. These cDNAs encoded for the subunit G of the vacuolar H+-ATPase, the first one identified in plants. Analysis of mRNA distribution showed a maximum level in the leaves and in the stem of the apical part of the tobacco plant. Heterologous functional complementation of the yeast mutant (deltavma10::URA3) was achieved with the two cDNAs. After fractionation of microsomal membranes on linear sucrose gradient, Western blots were performed using antibodies against recombinant protein and three peaks were identified: one which comigrated with the tonoplast marker and the others at slightly higher density corresponding to endoplasmic reticulum and to plasma membrane fractions.
Amino Acid Sequence↗
Discrimination against gay, lesbian and bisexual family physicians by patients.
BACKGROUND: Discrimination against gay, lesbian and bisexual (GLB) patients by physicians is well known. Discrimination against GLB physicians by their colleagues and superiors is also well known and includes harassment, denial of positions and refusal to refer patients to them. The purpose of this study was to identify and quantify the attitudes of patients toward GLB physicians. METHODS: Telephone interviews were conducted with 500 randomly selected people living in a large urban Canadian city. Subjects were asked if they would refuse to see a GLB family physician and, if so, to describe the reason why. They were then given a choice of 6 reasons obtained from consultation with 10 GLB people and 10 heterosexual people. RESULTS: Of the 500 subjects 346 (69.2%) were reached and agreed to participate. Of the 346 respondents 41 (11.8%) stated that they would refuse to see a GLB family physician. The 2 most common reasons for the discrimination (prevalence rate more than 50%) were that GLB physicians would be incompetent and the respondent would feel "uncomfortable" having a GLB physician. Although more male than female respondents discriminated against GLB physicians, the difference was not statistically significant. The proportion of male and female respondents who discriminated increased with age (p < 0.01). CONCLUSIONS: The observed prevalence of patient discrimination against GLB family physicians is significant. The results suggest that the discrimination is based on emotional reasons and is not related to such factors as misinformation about STDs and fear of being thought of sexually. Therefore, educational efforts should be directed against general perceptions of homosexuality rather than targeting specific medical concerns.
Adult↗
Carpal tunnel syndrome: validation of an interview questionnaire on occupational exposure.
The objectives of this study were 1) to summarize in a clinically meaningful way information on occupational risk factors for carpal tunnel syndrome (CTS), and 2) to test a questionnaire on risk factors that could be used by physicians with their patients. For the two objectives, a systematic literature review was performed and synthetized graphically, and a questionnaire was developed and administered to 238 patients who underwent release surgery for CTS. Patients were classified in four groups according to the incidence rate of CTS surgery in their occupation. Answers to the questionnaire on exposure to risk factors for CTS were compared between these four groups with the hypothesis that the group with the highest incidence would report the highest exposure. The results showed that questioning workers on the amount of force required to perform tasks that are "especially demanding" for the wrists or hands is both useful clinically and valid to be used by the clinician to make a judgement on the occupational nature of CTS. Repetitiveness and segmental exposure to vibrations or to cold are potentially useful and will need further validation. There is no evidence at present that posture or motion of the wrists is potentially useful to describe occupational exposure when questioning patients with CTS.
Adult↗
New zwitterionic detergents improve the analysis of membrane proteins by two-dimensional electrophoresis.
Severe quantitative loss of protein is often observed in high-resolution two-dimensional electrophoresis of membrane proteins, while the resolution is usually not affected. To improve the solubility of proteins in this technique, we tested denaturing cocktails containing various detergents and chaotropes. Best results were obtained with a denaturing solution containing urea, thiourea, and zwitterionic detergents, synthesized for this purpose. Among the dozen detergents synthesized and tested, amidosulfobetaines with an alkyl tail containing 14-16 carbons proved most efficient, solubilizing previously undetected membrane proteins.
Animals↗
Venous duplex scanning for unilateral symptoms: when do we need a contralateral evaluation?
OBJECTIVES: Determine the need for bilateral duplex scanning (DS) in patients with unilateral symptoms of acute DVT of the leg. DESIGN: Prospective study. MATERIALS: One thousand, one hundred and sixty-one consecutive patients with recent unilateral symptoms of pain or swelling. METHODS: Bilateral DS were performed and demographic data including risk factors for DVT were entered into a computerised database. RESULTS: Of the 250 cases (22%) of acute DVT, thrombus was confined to the symptomatic limb in 80% (200/250) and to the asymptomatic limb (AL) in 5% (12/250), while bilateral DVT was found in 15% (38/250). The management was not altered by the contralateral DS findings in any patient with bilateral thrombus. Ten of the 12 cases of DVT confined to the AL were localised to the infrapopliteal level; advanced malignancy, recent joint surgery or hypercoagulability were noted in nine patients, including all those requiring treatment. CONCLUSIONS: In the presence of unilateral symptoms of DVT, we recommend DS of the symptomatic extremity only; bilateral examination should be confined to patients with normal duplex findings in the symptomatic limb following recent joint surgery, or in the presence of advanced malignancy or hypercoagulability. Bilateral DS would therefore be required in approximately 11% of cases with unilateral symptoms of DVT.
Acute Disease↗
Use of a proteome strategy for tagging proteins present at the plasma membrane.
A plasma membrane (PM) fraction was purified from Arabidopsis thaliana using a standard procedure and analyzed by two-dimensional (2D) gel electrophoresis. The proteins were classified according to their relative abundance in PM or cell membrane supernatant fractions. Eighty-two of the 700 spots detected on the PM 2D gels were microsequenced. More than half showed sequence similarity to proteins of known function. Of these, all the spots in the PM-specific and PM-enriched fractions, together with half of the spots with similar abundance in PM fraction and supernatant, have previously been found at the PM, supporting the validity of this approach. Extrapolation from this analysis indicates that (i) approximately 550 polypeptides found at the PM could be resolved on 2D gels; (ii) that numerous proteins with multiple locations are found at the PM; and (iii) that approximately 80% of PM-specific spots correspond to proteins with unknown function. Among the later, half are represented by ESTs or cDNAs in databases. In this way, several unknown gene products were potentially localized to the PM. These data are discussed with respect to the efficiency of organelle proteome approaches to link systematically genomic data to genome expression. It is concluded that generalized proteomes can constitute a powerful resource, with future completion of Arabidopsis genome sequencing, for genome-wide exploration of plant function.
Amino Acid Sequence↗
Analyses of epidemiologic studies of back belts.
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Back Injuries↗
Laryngeal cancer: is computed tomography a valuable imaging technique? A retrospective analysis.
OBJECTIVE: Our objectives were threefold: to evaluate the sensitivity and specificity of laryngeal computed tomography (CT) in the evaluation of laryngeal cancer, to determine the positive and negative predictive values of CT in assessing laryngeal cancer with respect to patient outcome, and to compare the CT staging of laryngeal cancer with endoscopy. METHODS: We reviewed the records of 77 consecutive patients with endoscopically proven laryngeal cancer. All patients underwent nonhelical CT evaluation of the larynx, with 23 subsequently undergoing surgery and 54 undergoing radiotherapy. The CT findings in the surgical cohort were compared with the pathologic analysis of resected specimens and with endoscopic data using a predetermined checklist of 14 regions of surgical interest. All the CT data in the radiotherapy cohort were compared with patient outcome in an attempt to define regions of tumour involvement that may predict disease recurrence after radiotherapy. RESULTS: CT evaluation of laryngeal cancer had an overall sensitivity of 74% and a specificity of 93%. In the radiotherapy cohort, CT had an overall positive predictive value of 51% and a negative predictive value of 62% for disease recurrence after radiotherapy. Compared with endoscopic examination, CT resulted in upgrading of clinical staging in 43% of patients in the surgical cohort and 33% of patients in the radiotherapy cohort. CONCLUSION: Our findings suggest that, despite the superiority of CT over endoscopy in the assessment of laryngeal cancer, this imaging technique is weak in staging advanced laryngeal cancer and is poor in predicting clinical outcome following radiotherapy.
Carcinoma, Squamous Cell↗
Stimulation of RAR alpha activation function AF-1 through binding to the general transcription factor TFIIH and phosphorylation by CDK7.
The activity of the N-terminal activation function AF-1 of RAR alpha1 is abrogated upon mutation of a phosphorylatable serine residue (Ser-77). Recombinant RAR alpha was phosphorylated by a variety of proline-directed protein kinases in vitro. However, only the coexpression of cdk7 stimulated Ser-77 phosphorylation in vivo and enhanced transactivation by RAR alpha, but not by a S77A RAR mutant. Both free CAK (cdk7, cyclin H, MAT1) and the CAK-containing general transcription factor TFIIH phosphorylated Ser-77 in vitro. Furthermore RAR alpha bound free CAK and purified TFIIH in vitro, and RAR alpha-TFIIH complexes could be isolated from HeLa nuclear extracts. These findings represent the first example of activation of a transactivator through binding to and phosphorylation by a general transcription factor.
Amino Acid Sequence↗