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1.
Fam Cancer ; 20(4): 305-316, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33532948

RESUMEN

The rhabdoid tumor (RT) predisposition syndromes 1 and 2 (RTPS1 and 2) are rare genetic conditions rendering young children vulnerable to an increased risk of RT, malignant neoplasms affecting the kidney, miscellaneous soft-part tissues, the liver and the central nervous system (Atypical Teratoid Rhabdoid Tumors, ATRT). Both, RTPS1&2 are due to pathogenic variants (PV) in genes encoding constituents of the BAF chromatin remodeling complex, i.e. SMARCB1 (RTPS1) and SMARCA4 (RTPS2). In contrast to other genetic disorders related to PVs in SMARCB1 and SMARCA4 such as Coffin-Siris Syndrome, RTPS1&2 are characterized by a predominance of truncating PVs, terminating transcription thus explaining a specific cancer risk. The penetrance of RTPS1 early in life is high and associated with a poor survival. However, few unaffected carriers may be encountered. Beyond RT, the tumor spectrum may be larger than initially suspected, and cancer surveillance offered to unaffected carriers (siblings or parents) and long-term survivors of RT is still a matter of discussion. RTPS2 exposes female carriers to an ill-defined risk of small cell carcinoma of the ovaries, hypercalcemic type (SCCOHT), which may appear in prepubertal females. RT surveillance protocols for these rare families have not been established. To address unresolved issues in the care of individuals with RTPS and to propose appropriate surveillance guidelines in childhood, the SIOPe Host Genome working group invited pediatric oncologists and geneticists to contribute to an expert meeting. The current manuscript summarizes conclusions of the panel discussion, including consented statements as well as non-evidence-based proposals for validation in the future.


Asunto(s)
Neoplasias Encefálicas , Neoplasias del Sistema Nervioso Central , Neoplasias Renales , Tumor Rabdoide , Neoplasias Encefálicas/genética , Preescolar , ADN Helicasas/genética , Femenino , Pruebas Genéticas , Humanos , Neoplasias Renales/genética , Proteínas Nucleares , Tumor Rabdoide/diagnóstico , Tumor Rabdoide/genética , Proteína SMARCB1/genética , Factores de Transcripción/genética
2.
Sleep Med ; 15(3): 322-8, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24468102

RESUMEN

BACKGROUND: Nighttime traffic noise is associated with sleep disturbances, but sleep fragmentation and sleep-disordered breathing (SDB) have not been demonstrated in individuals living near busy roads. METHODS: We asked 1383 participants to answer a health questionnaire and to undergo 24-h electrocardiogram (ECG). Nocturnal ECG records were used to calculate the very low frequency index (VLFI) interval, a surrogate marker of sleep fragmentation. Distances of participants' addresses to roadways were calculated using the VECTOR25© Swisstopo roads classification, a traffic noise proxy. Distances of homes within 100 or 50 m of major roads defined proximity to busy roads. Adjusted multivariate logistic regressions analyzed associations between the distance of home to main roads and VLFI or self-reported SDB. RESULTS: Distance of participants' homes to main roads was significantly associated with the VLFI in women (odds ratio [OR], 1.58 [confidence interval {CI}, 1.03-2.42]; P = .038) but not in men (OR, 1.35 [CI, 0.77-2.35]; P = .295). Women under hormonal replacement therapy (HRT) were at higher risk for increased VLFI when living close to main roads (OR, 2.10 [CI, 1.20-3.68]; P = .01) than untreated women (P = .584). Associations with self-reported SDB were not statistically relevant. CONCLUSIONS: In our large population, women living close to main roads were at significantly higher risk for sleep fragmentation than men. The 2-fold higher risk for menopausal women under HRT underscores the vulnerability of this group.


Asunto(s)
Vehículos a Motor , Ruido/efectos adversos , Síndromes de la Apnea del Sueño/etiología , Privación de Sueño/etiología , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Factores Sexuales , Encuestas y Cuestionarios
3.
Ther Umsch ; 64(6): 331-5, 2007 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-17877210

RESUMEN

Communication is a central part of physicians' professional activities. Encounters with good physician-patient communication have been shown to be associated with a higher degree of exchange of information, patient satisfaction, compliance and a more favourable symptoms'course, and with a lower frequency of wrong diagnoses. Gender differences in verbal behaviour and language use have been observed among physicians with regard to form and content of questions, informational manner, partnership building in the physician-patient relation, emotionally focused talk, as well as with regard to length of speech and of visits. Patient gender is associated with the readiness to discuss health issues, with experiencing health and diseases, and with variability of symptom descriptions. Gender constellations have an impact on content and interaction of discourse. Introducing a "second gender thought" on whether patient gender or own gender representations may have influenced diagnostic or therapeutic decisions might help to eventually modify such impact.


Asunto(s)
Comunicación , Relaciones Médico-Paciente , Femenino , Humanos , Relaciones Interpersonales , Masculino , Factores Sexuales
4.
Swiss Med Wkly ; 131(21-22): 311-9, 2001 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-11584693

RESUMEN

QUESTION UNDER STUDY: Physicians play a key role in motivating women to undergo mammography screening. In 1998 we assessed Swiss physicians' attitudes to mammography screening and their prescription behaviour in this regard. METHODS: All female physicians and every second male physician aged 50-69 who were either not board-certified or board-certified in general practice, internal medicine, or obstetrics/gynaecology were sent a questionnaire. The response rate was 50% and thus 738 questionnaires were included in this study. Of the study population 39% were female and 61% male physicians. The distribution of professional backgrounds was: 27% board-certified general practitioners; 23% board-certified internists; 11% board-certified gynaecologists; 39% not board-certified. RESULTS: 55% of all study participants were in favour of a mammography screening programme for women aged over 50 in Switzerland, but breast self-examination and clinical breast examination were judged to have a more positive impact on breast cancer survival. Among clinically practising physicians, 22% reported generally prescribing biannual screening mammographies for women aged 50-69. Irrespective of other determinants, physicians from the Italian- and French-speaking parts of Switzerland prescribed screening mammographies more often than their colleagues from the German-speaking part (odds ratio [OR] 2.5; 95% confidence interval [CI] 1.5-4.2). Clinical practice in obstetrics/gynaecology (OR 2.4; CI 1.3-4.2) and a self-reported high level of knowledge concerning mammography screening (OR 1.9; CI 1.1-3.2) were also positively associated with the prescription of screening mammography. CONCLUSIONS: Since mammography screening programmes exist in only three French-speaking cantons of Switzerland (VS; VD; GE), the gap in prescription of screening mammographies between French/Italian- and German-speaking regions must be narrowed to prevent a higher prevalence of side effects from opportunistic screening among German-speaking women. There is a need to educate physicians and the political community regarding the risks and benefits of mammography screening.


Asunto(s)
Actitud del Personal de Salud , Neoplasias de la Mama/epidemiología , Mamografía/estadística & datos numéricos , Tamizaje Masivo , Médicos Mujeres , Pautas de la Práctica en Medicina , Prescripciones , Anciano , Neoplasias de la Mama/diagnóstico por imagen , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Suiza/epidemiología
5.
Soz Praventivmed ; 45(5): 208-17, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11081239

RESUMEN

Inconsistencies across studies on the association of environmental tobacco smoke (ETS) and pulmonary function may be clarified addressing potentially susceptible subgroups. We determined the association of ETS exposure at work with FVC, FEV1, and FEF25-75% in life-time never smokers (N = 3534) of the SAPALDIA random population sample (age 18-60). We considered sex, bronchial reactivity, and asthma status as a priori indicators to identify susceptible riskgroups. The multivariate regression models adjusted for height, age, education, dust/aerosol exposure, region, and ETS at home. Overall, ETS was not significantly associated with FVC (0.7%; -0.4 to +1.8), FEV1 (-0.1%; 95% CI: -1.3 to +1.1) or FEF25-75% (-1.9%; -4.2 to +0.5). Effects were observed among asthmatics (n = 325), FEV1 (-4.8%; 0 to -9.2); FEF25-75% (-12.4%; -3.7 to -20.4); FVC: (-1.7%; +2.1 to -5.5), particularly in asthmatic women (n = 183): FVC -4.4% (-9.6 to +1.1); FEV1: -8.7% (-14.5 to -2.5); FEF25-75%: -20.8% (-32 to -7.6), where duration of ETS exposure at work was associated with lung function (FEV1 -6% per hour of ETS exposure at work (p = 0.01); FEF25-75%: -3.4%/h (p < 0.05). In non-asthmatic women (n = 1963) and in men no significant effect was observed. The size of the observed effect among susceptible subgroups has to be considered clinically relevant. However, due to inherent limitations of this cross-sectional analysis, selection or information biases may not be fully controlled. For example, asthmatic women reported higher ETS exposure at work than asthmatic men. Given the public health importance to identify susceptible subgroups, these results ought to be replicated.


Asunto(s)
Contaminantes Ocupacionales del Aire/efectos adversos , Asma/etiología , Mediciones del Volumen Pulmonar , Enfermedades Profesionales/etiología , Contaminación por Humo de Tabaco/efectos adversos , Adolescente , Adulto , Asma/diagnóstico , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Multicéntricos como Asunto , Enfermedades Profesionales/diagnóstico , Factores de Riesgo , Suiza
6.
Plant Sci ; 158(1-2): 107-113, 2000 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-10996250

RESUMEN

Ferredoxin:thioredoxin reductase (FTR) is a heterodimeric Fe&z.sbnd;S containing disulfide reductase involved in the light-dependent activation of photosynthetic enzymes. We have designed a dicistronic construct for the heterologous expression of this nucleus encoded chloroplast protein in Escherichia coli. The coding sequences for the two mature subunits have been inserted in tandem into the expression vector pET-3d. This dicistronic construct is correctly translated yielding soluble, perfectly functional FTR. The recombinant enzyme is composed of both subunits, contains the correctly inserted Fe&z.sbnd;S cluster as evidenced by its spectral properties and is indistinguishable from the enzyme isolated from leaves in its capacity to activate chloroplast fructose-1,6-bisphosphatase, one of the well known light activated enzymes of the Calvin cycle.

7.
Am J Respir Crit Care Med ; 160(2): 427-34, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10430709

RESUMEN

We used 3-wk peak expiratory flow (PEF) measurements (twice daily) made in the diary study of the population-based Swiss Study on Air Pollution and Lung Disease in Adults to describe PEF-variability (PEF(var)) (amplitude as a percent of the mean, PEF [i.e., difference between morning and evening values divided by the mean]) in the study population and in five subgroups (physician-diagnosed asthma; current asthma, or physician-diagnosed asthma plus asthma attacks and/or medication; history of wheezing without a cold; hyperreactive; and nonsymptomatic). We assessed the performance of PEF(var) as a potential tool with which to screen for asthma. Alternatively, subjects with a PEF(var) of >/= 20%, >/= 30%, and >/= 50% on at least 2 d were considered to have high variability. The analyses were conducted for subgroups with different pretest probabilities for asthma-related conditions. The median PEF(var) was 4.5%. Among asthmatic subjects, women had nonsignificantly higher PEF(var) values than did men. In all other groups, women had significantly lower PEF(var). Both in the entire population and in subgroups with a higher pretest probability for asthma-related conditions, screening performance of PEF was limited. A PEF(var) of >/= 20% on at least 2 d detected current asthma with a sensitivity of 36% (specificity = 90%; positive predictive value = 16.4%). Results were better among subjects with a history of wheezing without colds (sensitivity = 40.4%; specificity = 83.6%; positive predictive value = 45.2%). PEF(var), a useful measure both clinically and in epidemiology, is of limited value when unselected populations are screened for asthma-related conditions, since the overlap of PEF(var) distributions across subgroups is large.


Asunto(s)
Contaminación del Aire/efectos adversos , Asma/diagnóstico , Tamizaje Masivo , Ápice del Flujo Espiratorio , Vigilancia de la Población , Adolescente , Adulto , Asma/epidemiología , Ritmo Circadiano , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ápice del Flujo Espiratorio/efectos de los fármacos , Valor Predictivo de las Pruebas , Factores de Riesgo , Suiza/epidemiología
8.
Soz Praventivmed ; 42(2): 67-84, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9151378

RESUMEN

SAPALDIA--the Swiss Study on Air Pollution and Lung Diseases in Adults--focuses on the long term health effects of low to moderate levels of air pollutants as typically seen in different parts of Switzerland. The aim of the SAPALDIA cross-sectional study carried out in 1991 was to determine the prevalence of bronchial asthma, chronic bronchitis and allergic conditions in the adult population of Switzerland and to identify and to determine the respective importance of potentially influencing factors. These could be both personal (smoking habits, allergy status, family history, occupation) and environmental (outdoor and indoor pollution, aeroallergens, climate). A further aim of the cross-sectional study consisted in the identification of individuals susceptible to present symptoms during a two year observation period and to be included in the SAPALDIA follow-up study. This technical report represents the methodological documentation for the cross-sectional study of SAPALDIA. The instruments and the methods of standardisation are presented and discussed. The medical examination consisted of a computerised interview using a standardised questionnaire, the taking of a blood sample for serological tests, allergy skin testing, the measurement of end expiratory CO and body height, and pulmonary function testing followed by methacholine challenge testing or bronchodilatation testing. The pattern of participation and the 9651 participants of the study, representing 59.3% of the sample, are described. Based on information on non-participants gained by telephone interviews and mailed short questionnaires, possible selection biases are quantified and discussed.


Asunto(s)
Contaminantes Atmosféricos/efectos adversos , Enfermedades Pulmonares/epidemiología , Adulto , Anticuerpos/aislamiento & purificación , Asma/epidemiología , Pruebas de Provocación Bronquial , Bronquitis/epidemiología , Estudios Transversales , Femenino , Humanos , Enfermedades Pulmonares/diagnóstico , Enfermedades Pulmonares/etiología , Masculino , Persona de Mediana Edad , Control de Calidad , Pruebas de Función Respiratoria , Hipersensibilidad Respiratoria/epidemiología , Muestreo , Pruebas Cutáneas , Fumar , Suiza/epidemiología , Urbanización
9.
RNA ; 1(10): 1079-88, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8595563

RESUMEN

The 4,144 nt Euglena gracilis chloroplast psbC intron 2 has been characterized as a single, cis-spliced 593 nt group II intron interrupted by an open reading frame of 758 codons in the loop region of domain IV. The 2,277 nt coding region of orf 758 is interrupted by two additional group II introns of 369 nt and 352 nt. Another 553 nt group II intron is located in the 5' untranslated leader region of orf 758. Because the psbC intron 2 orf encodes a maturase-like protein that has reverse transcriptase domains and a domain X characteristic of group II intron-encoded proteins, the locus has been designated mat2. The psbC intron 2 is the first member of a new category of twintron, characterized by introns within a gene within another intron. A potential role of psbC intron 2 as a "founder" intron involved in the spread of introns to new sites in the plastid genome of the Euglenophycae is discussed.


Asunto(s)
Cloroplastos/genética , Euglena gracilis/genética , Intrones , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Evolución Biológica , Cloroplastos/metabolismo , Cartilla de ADN/genética , Endorribonucleasas/genética , Endorribonucleasas/metabolismo , Euglena gracilis/metabolismo , Genoma , Modelos Moleculares , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Sistemas de Lectura Abierta , Reacción en Cadena de la Polimerasa , Precursores del ARN/química , Precursores del ARN/genética , Precursores del ARN/metabolismo , Empalme del ARN , ARN Protozoario/química , ARN Protozoario/genética , ARN Protozoario/metabolismo , Homología de Secuencia de Aminoácido
10.
Plant Mol Biol ; 27(6): 1221-6, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7766904

RESUMEN

In close vicinity of two fus nuclear genes (chloroplast-specific translation elongation factor cEF-G) of soybean (Glycine max) we localized a split nuclear gene coding for a protein with tetratricopeptide repeats (TPR). A full-length cDNA was sequenced (1871 nucleotides). It encodes a protein (569 amino acids) with high sequence identity to the yeast STI1 stress-inducible and the human transformation-sensitive IEF SSP 3521 protein which both carry TPR elements. The soybean gene is heat-inducible. This is the first evidence for the existence of plant genes coding for proteins which belong to the TPR family. We call the gene gmsti and the protein GMSTI in analogy to the yeast counterpart.


Asunto(s)
Glycine max/genética , Proteínas de Choque Térmico/genética , Proteínas de Plantas/genética , Secuencia de Aminoácidos , Secuencia de Bases , ADN de Plantas , Regulación de la Expresión Génica de las Plantas , Calor , Humanos , Datos de Secuencia Molecular , Mapeo Restrictivo , Homología de Secuencia de Aminoácido
11.
Biochim Biophys Acta ; 1218(1): 75-81, 1994 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-8193167

RESUMEN

The clustered genes psbD and psbC covering together close to 22,000 nucleotides contain ten and eleven exons, respectively. The corresponding translation products, i.e, Photosystem II core 34 kDa (D2) protein and the CP43 chlorophyll binding protein are highly conserved. Introns vary in length from 305 to 4144 nucleotides. The two genes have about 900 nucleotides in common including an intron. To obtain stable mRNAs of about 1400 (psbD) and 1500 (psbC) nucleotides the pre-transcripts must undergo differential processing and/or splicing events within the overlapping region.


Asunto(s)
Cloroplastos/metabolismo , Euglena gracilis/genética , Familia de Multigenes , Proteínas del Complejo del Centro de Reacción Fotosintética/genética , Procesamiento Postranscripcional del ARN , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , ADN , Complejos de Proteína Captadores de Luz , Datos de Secuencia Molecular , Complejo de Proteína del Fotosistema II , Empalme del ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de Secuencia
12.
Biochim Biophys Acta ; 1183(1): 207-9, 1993 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-7916641

RESUMEN

We determined the complete nucleotide sequence of a cDNA clone encoding the smaller, catalytic subunit of ferredoxin-thioredoxin reductase from corn chloroplasts. The translated protein sequence, representing a subunit of 12.9 kDa shows 80% identity with the protein sequence from spinach and contains seven Cys residues all at conserved positions.


Asunto(s)
Oxidorreductasas/genética , Zea mays/genética , Secuencia de Aminoácidos , Secuencia de Bases , Cloroplastos/enzimología , Clonación Molecular , Proteínas Hierro-Azufre , Datos de Secuencia Molecular , Oxidorreductasas/química
13.
Biochim Biophys Acta ; 1174(2): 191-4, 1993 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-8357836

RESUMEN

A plant nuclear gene coding for a chloroplast specific translation elongation factor EF-G (cEF-G) was cloned and sequenced for the first time. We screened two partial soybean genomic libraries with a short PCR amplified pea DNA probe constructed according to the N-terminal peptide sequence of pea chloroplast EF-G. The gene is three times split, codes for a chloroplast type transit peptide and a protein very similar to bacterial translation elongation factor EF-G. The gene is expressed as evidenced by Northern hybridisations.


Asunto(s)
Cloroplastos/metabolismo , Glycine max/genética , Factores de Elongación de Péptidos/genética , Proteínas de Plantas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Datos de Secuencia Molecular , Factor G de Elongación Peptídica , Homología de Secuencia de Aminoácido
14.
Nucleic Acids Res ; 21(15): 3537-44, 1993 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-8346031

RESUMEN

We report the complete DNA sequence of the Euglena gracilis, Pringsheim strain Z chloroplast genome. This circular DNA is 143,170 bp, counting only one copy of a 54 bp tandem repeat sequence that is present in variable copy number within a single culture. The overall organization of the genome involves a tandem array of three complete and one partial ribosomal RNA operons, and a large single copy region. There are genes for the 16S, 5S, and 23S rRNAs of the 70S chloroplast ribosomes, 27 different tRNA species, 21 ribosomal proteins plus the gene for elongation factor EF-Tu, three RNA polymerase subunits, and 27 known photosynthesis-related polypeptides. Several putative genes of unknown function have also been identified, including five within large introns, and five with amino acid sequence similarity to genes in other organisms. This genome contains at least 149 introns. There are 72 individual group II introns, 46 individual group III introns, 10 group II introns and 18 group III introns that are components of twintrons (introns-within-introns), and three additional introns suspected to be twintrons composed of multiple group II and/or group III introns, but not yet characterized. At least 54,804 bp, or 38.3% of the total DNA content is represented by introns.


Asunto(s)
Cloroplastos/química , ADN Protozoario/química , Euglena gracilis/genética , Animales , Secuencia de Bases , Evolución Biológica , Mapeo Cromosómico , Codón , ADN Circular/química , Intrones , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Operón , Fotosíntesis/genética , Biosíntesis de Proteínas , ARN Ribosómico/genética , ARN de Transferencia/genética , Secuencias Repetitivas de Ácidos Nucleicos , Proteínas Ribosómicas/genética , Transcripción Genética
15.
Plant Mol Biol ; 20(2): 301-6, 1992 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-1391773

RESUMEN

The recently cloned gene for spinach chloroplast thioredoxin f was subcloned in a modified pKK233-2 expression vector and used for transformation of Escherichia coli cells containing the Iq plasmid. After induction with IPTG (isopropyl-beta-D-thiogalactoside) the transformed cells produce the chloroplast protein in large amounts as insoluble deposit within the cell. The protein has been solubilized, purified and analysed for activity. It shows no difference in catalytic activity from native spinach chloroplast thioredoxin f. Its electrophoretic behaviour suggests that the native thioredoxin f may have a different N-terminus than was assumed on the basis of the protein sequencing results.


Asunto(s)
Cloroplastos/metabolismo , Escherichia coli/genética , Proteínas de Plantas/genética , Plantas/genética , Tiorredoxinas , Transformación Bacteriana , Secuencia de Aminoácidos , Secuencia de Bases , Tiorredoxinas en Cloroplasto , Clonación Molecular , ADN , Immunoblotting , Focalización Isoeléctrica , Datos de Secuencia Molecular , Proteínas de Plantas/biosíntesis , Proteínas de Plantas/aislamiento & purificación , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación
16.
FEBS Lett ; 303(2-3): 181-4, 1992 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-1607017

RESUMEN

We mapped and sequenced a novel chloroplast gene encoding a protein (348 amino acids) which shows a high sequence identity with both the decoded nuclear cs(ch-42) gene product of Arabidopsis thaliana, and the C-terminal half of the decoded 'crtA' gene product of Rhodobacter capsulatus. The chloroplast gene (ccsA) is split (two exons) and transcribed into a stable mRNA of about 1200 nucleotides. The putative protein may be involved in the biosynthesis of photosynthetic pigments.


Asunto(s)
Cloroplastos/metabolismo , Euglena gracilis/genética , Proteínas Nucleares/genética , Plantas/genética , Proteínas Protozoarias/genética , Secuencia de Aminoácidos , Animales , Northern Blotting , Datos de Secuencia Molecular , Mapeo Restrictivo , Homología de Secuencia de Ácido Nucleico , Transcripción Genética
17.
Thymus ; 18(2): 67-77, 1991 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1926293

RESUMEN

Primary murine thymus cell cultures consist of thymus epithelial cells, macrophages and interdigitating dendritic cells. Results of the present study indicated that the proportion of macrophage-like cells in cultures was directly related to the age of the thymus donors through 7 weeks of age. We standardized procedures to compare primary thymic cultures derived from mice, 1 day to 115 days of age. Cultures were grown 6 to 8 days and then tested for nonspecific esterase, acid phosphatase, phagocytosis of latex beads, Fc receptors, and MAC-1 staining. Less than 10% macrophage-like cells were identified in cultures from mice 1 to 3 days-old, but the proportion increased to 50% macrophage-like cells in cultures from 7 week-old mice. Thereafter the proportion plateaued although there was considerable variation among older mice. Further studies showed that the proportions of macrophage-like cells was not affected by the number of cells initially seeded into culture, nor by the amount of serum added to the culture medium. These data suggest that macrophage/interdigitating cell precursors immigrate into the thymus for 4 to 6 weeks after birth and support the hypothesis that these precursors may be influenced to differentiate into thymus macrophages or interdigitating cells by the thymic microenvironment.


Asunto(s)
Factores de Edad , Macrófagos/citología , Timo/citología , Animales , Células Cultivadas , Femenino , Inmunohistoquímica , Antígeno de Macrófago-1/análisis , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Receptores Fc/análisis
18.
Plant Mol Biol ; 17(3): 351-60, 1991 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1715783

RESUMEN

A cDNA and a genomic DNA library from soybean (Glycine max L.) were used to identify and sequence two genes coding for the alpha-subunit of the translation elongation factor eEF-1. Within the coding part, the two genes (tefS1 and tefS2) diverge in 80 wobble positions thus yielding an identical protein composed of 447 amino acids. The soybean protein has about 95% similarity with eEF-1 alpha proteins of Arabidopsis thaliana and tomato. Both genes S1 and S2 contain, within the coding part at a site seemingly unique to higher plants, a single short intron of 86 and 116 nucleotides, respectively. The untranslated leader part of both genes is interrupted by a large intron (partially sequenced). Genes S1 and S2 are transcribed in young leaves. cDNA and gene-specific oligonucleotide probes interact with a unique transcript of close to 1.9 kb. Northern hybridization studies using RNAs from dark- and light-grown seedlings show that light sharply increases the level of stable transcripts (1.9 kb). A peak value is measured after about 3 h of illumination, afterwards the transcript concentration drops to about 10% of the peak value. Genes S1 and S2 follow a similar transcription pattern in developing seedling leaves, which is distinct from that of the rbcS genes measured in parallel experiments. According to northern results, S1 transcripts are more abundant in leaves at all measured stages of development than S2 transcripts.


Asunto(s)
Glycine max/genética , Factores de Elongación de Péptidos/genética , Proteínas de Plantas/genética , Secuencia de Aminoácidos , Autorradiografía , Secuencia de Bases , Northern Blotting , Southern Blotting , Clonación Molecular , ADN/aislamiento & purificación , Exones , Biblioteca Genómica , Intrones , Datos de Secuencia Molecular , Factor 1 de Elongación Peptídica , Señales de Clasificación de Proteína/genética , ARN/aislamiento & purificación , Ribulosa-Bifosfato Carboxilasa/genética , Semillas/metabolismo , Transcripción Genética
19.
Biochim Biophys Acta ; 1089(2): 213-9, 1991 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-1711372

RESUMEN

We previously reported about Escherichia coli transformation experiments yielding streptomycin-resistant cells carrying a C912 to T transition in a plasmid-born 16S rRNA gene. These experiments were based on results obtained with streptomycin-resistant Euglena chloroplasts bearing an equivalent mutation in the single chloroplast 16S rRNA gene. We extended this study and transformed E. coli with plasmid constructs having a mutated 16S rRNA gene at position 914 (A to C) or a double mutation at positions 912 and 888 (C to T:G to A) or a mutation in the S12 gene (Lys-42 to Thr). We tested the transformed cells before and after a screening procedure in the presence of streptomycin. We find that the plasmid-born mutations protect colonies against a short streptomycin exposure, but ribosomes carrying mutated 16S rRNA do not significantly reduce codon misreading in vitro. However, ribosomes isolated from transformed cells after the screening procedure resist misreading. These ribosomes have acquired a second mutation in the S12 protein as shown in one case by sequencing and by transformation experiments. Furthermore, we show that the A914 to C mutation prevents (strongly reduces) base methylation in the central domain of 16S rRNA.


Asunto(s)
Farmacorresistencia Microbiana/genética , Escherichia coli/genética , Mutación , Estreptomicina/farmacología , Secuencia de Bases , Cloroplastos , Escherichia coli/efectos de los fármacos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Plásmidos , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Proteínas Ribosómicas/genética
20.
Nucleic Acids Res ; 18(1): 75-82, 1990 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-2106666

RESUMEN

A cDNA library from the protist Euglena gracilis was used to isolate and sequence an ORF coding for the elongation factor protein EF-1 alpha. The decoded amino acid sequence (MW, 48'515) is to 75-80% identical with other eukaryotic EF-1 alpha sequences but only to 24% identical with the Euglena chloroplast EF-Tu. Homologous DNA probes interact with multiple fragments of Euglena nuclear restricted DNA typical for a multimembered gene family. We present the restriction sites map of four tef nuclear gene loci and postulate that the nuclear genome also contains tef related sequences (e.g. pseudogenes). Expression of tef gene(s) is monitored by Northern hybridization and the 5' end of a stable transcript (1.5 kb) is sequenced and shown to precede the start codon by 29 positions only. The steady state concentration of the 1.5 kb mRNA is not influenced by switching cell growth conditions from dark to light (chloroplast development).


Asunto(s)
Euglena gracilis/genética , Factores de Elongación de Péptidos/genética , Secuencia de Aminoácidos , Animales , Southern Blotting , Núcleo Celular , Clonación Molecular , ADN/genética , Expresión Génica , Genes , Datos de Secuencia Molecular , Factor 1 de Elongación Peptídica , Mapeo Restrictivo
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