Acta cientifica venezolana最新文献

{"title":"[Mitochondria and apoptosis].","authors":"Francisco Arvelo","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>It is now accepted that mitochondria are endosymbionts, originated in aerobic bacteria which were integrated by the ancestor of eukaryotic cells. A part of the apoptotic machinery could exist in unicellular eukaryotic and some controlling apoptosis components might be present in prokaryotes. It is therefore possible that the mechanism originally involved in the maintenance of the symbiosis between the bacterial ancestor of the mitochondria and the host cell precursor of eukaryotes, provided the basis for the actual mechanism controlling cell survival. Metazoans would have improved this possibility by connecting to the mitochondria as principal effector of cellular death to the pathways of signal transduction. A variety of events appoint to the mitochondria as principal effector of the apoptosis. This including the release caspase activators (cytochrome c), changes in electron transport, loss of mitochondrial transmembrane potential, altered cellular oxidation-reduction, and participation of pro and antiapoptotic Bcl-2 proteins. The different signals that converge on mitochondria for activation or inhibition of these events, delineate several pathways in the physiology of the cellular death.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 4","pages":"297-306"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22552209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Reproductive phenology of three vegetation types from a coastal plain of Paraguana Penninsula, Venezuela].","authors":"Luis José Lemus-Jiménez,&nbsp;Nelson Ramírez","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Reproductive phenology of 51 plant species was evaluated according to life form and vegetation types in a coastal plain of the Paraguaná Peninsula, Estado Falcón, Venezuela. Plant species distribution according to three vegetation types (herbaceous littoral, herbaceous psamophil, and mangrove area) was determined. Life form frequency was different according to vegetation type. Herbaceous littoral and herbaceous psamophil vegetation were dominated by herbaceous species; woody species were mostly frequent in the mangrove vegetation. Phenological data revealed that 14 (27.5%) plant species flower and fruit year-round; 23 (45.1%) plant species flower and fruit at the beginning of the wet season; seven (13.7%) plant species flower at the end of wet season, and seven (13.7%) more flower at the beginning of the dry season. Flowsring and fruiting phenology showed similar frequency distribution during the year; reproductive phenology was independent of life forms. Flowering and fruiting peaks occurred during the rainy season and the beginning of the dry season for trees and perennial herbs, and from one to three months later for shrubs and annual herbs. The lowest proportion of flowering and fruiting occurred before rain increase for all life forms. Flowering and fruiting phenologies were similar for the three vegetation types evaluated: flowering peak occurred during the lowest value of precipitation, three to four months after precipitation peak, and fruiting peak occurred four months later from the precipitation peak. These results suggest that flowering and fruiting phenology were not affected by life form and vegetation types. The peaks of flowering and fruiting during the lowest values of precipitation may be considered as a slow and late response to the precipitation maximum, and to the proximity between maximum and minimum of precipitation.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 4","pages":"266-78"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22552332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Genetic control of the isocitrate dehydrogenase and shikimate dehydrogenase isoenzyme systems in Sesame (Sesamun indicum L.)].","authors":"Antonio J Díaz,&nbsp;Alfredo J Layrisse","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Taking into consideration that the ideal manipulation of isozymic markers needs knowledge of their genetic control, the aim of this study was to establish the inheritance and linkage degree of loci that control the expression of two sesame isozyme systems: isocitrate dehydrogenase (IDH) and shikimate dehydrogenase (SKD). The F2 electrophoretic behaviour of IDH and SKD from cultivars Turen x Arawaca cross was evaluated. The results suggest that IDH is controlled by two loci, Idh1 and Idh2 meanwhile SKD by only one, Skd1. The loci Idh1 and Skd1 showed three distinguishable patterns, corresponding to the homocygote genotypes and the heterocygote one, adjusted to a one-character common mendelian segregation 1:2:1. Cosegregation between Idh1 and Skd1 was independent.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 3","pages":"176-82"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22309370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Microsporogenesis y microgametogenesis de annatto (Bixa orellana L.)].","authors":"Claret Michelangeli,&nbsp;Ada Maureen Medina,&nbsp;Paola Artioli,&nbsp;Jonás Mata","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A series of buds of increasing maturity were individually sampled in order to examine cytological events of annatto (Bixa orellana L.), genotype Portuguesa. They were fixed in Carnoy II at 12:30 am, time of the highest rate of meiotic division. Three stain solutions were attempted. In the microspores mother cells, the use of acetic orcein 1% resulted in a good nucleus coloration and sharpness. In contrast, a well chromosome resolution was achieved with the application of propionic carmin 2%. The pollen grain mother cells (n = 8 chromosomes) at metaphase I were found in floral buds of 0.5 to 0.6 cm long; tetrad stage in buds of 0.6 to 0.7 cm long, uninucleate stage of microspores in buds of 0.7 to 0.8 cm long and the binucleate stage (pollen) in buds longer than 0.8 cm. Microphotographies showing the sequence of meiotic division (microsporogenesis) and subsequent mitosis to originate pollen grains were included.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 3","pages":"171-5"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22309369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Infrared laser photochemistry of metal carbonyls in the presence of cyclopentadiene].","authors":"Antonio M Barriola,&nbsp;Alfredo Fernández","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Mixtures of C5H6 and Fe(CO)5, Cr(CO)6, and Co2(CO)8 were irradiated in the gaseous phase with the P-20 line (944.21 cm-1) of a CW CO2 laser using SF6 as a sensitizer. The reaction products were metal particles and carbon monoxide, and in the C5H6/Fe(CO)5/SF6 mixture the iron dimer (C5H5)2Fe2(CO)4 was isolated.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 2","pages":"124-9"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22186065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heritability and correlation among some selected morphological traits and their relationship with fall armyworm damage in sweet corn.","authors":"Ramón A Rea,&nbsp;Clarence E Watson,&nbsp;William P Williams,&nbsp;Frank M Davis","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Fall armyworm [Spodoptera frugiperda J. E. Smith] (FAW) is a serious pest in field corn and sweet corn [Zea mays L.] in many parts of the world. Sweet corn germplasm with effective levels of resistance to damage by the fall armyworm is needed to transfer resistance to commercial hybrids. The objectives of this study were to estimate heritability and to estimate the correlation among some selected morphological traits and their relationship with FAW damage. Seven shrunken-2 (sh2) inbred lines and four commercial sh2 hybrids of sweet corn were crossed to Mp708, a FAW-resistant field corn line. The F2 populations were subdivided with one half being selected for the sh2 trait and the other half was left unselected. Parent, F2, and F3 populations were artificially infested with FAW and evaluated for leaf damage caused by FAW. Heritability estimates for FAW resistance ranged from 0.22 to 0.61 depending on method of estimation used. The highest correlations occurred between silk color and anther color (0.70) and silk color and glume color (0.49). There were no consistent correlations of most morphological traits with FAW damage. A linkage between white silk and shrunken-2 was observed.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 3","pages":"232-5"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22308151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Nutritional status by social stratification in Venezuelan school children].","authors":"Nayka Díaz,&nbsp;María Concepción Páez,&nbsp;Liseti Solano","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Unlabelled: </strong>This study assessed nutritional status of 590 children from Naguanagua, Valencia, attending school, aged between 4 and 14 years and its relation to social stratification, age and gender. Body dimension indicators were used for nutritional diagnosis. NCHS/OMS and Frisancho references were used for height/age (HA) weight/height (WH) cut-off points, and body mass index (BMI). Graffar modified by Mendez was used to establish socioeconomic status. Statistical analyses included descriptives, x2 and student-test.</p><p><strong>Results: </strong>91% of the children were in poverty, (71% relative and 20% critical). For HA, 6.4% classified as short, 27.6% in risk, and 4.9% tall for age without significative differences between sex. For WH, 0.6% were in nutritional deficit, 10.2% in risk and 22.1% in excess. For BMI, 12.9% had nutritional deficit, 7.3% excess but no significative differences for sex. Stunting and deficit were present in all age groups, but more significantly in those older than 10 years (12%; 23.9% respectively). Social stratification was associated with WH and BMI being deficit more prevalent in III and V class, predominating excess in IV class. The high prevalence of obesity makes this group as a high risk one for chronic degenerative diseases.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 4","pages":"284-9"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22552334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Muscle damage and autoantibody fixation in an experimental model of autoimmune myopathy.","authors":"Mercedes Losada,&nbsp;Ana Marina Wangüemert,&nbsp;Sonia H Torres,&nbsp;Noelina Hernández,&nbsp;Miriam Rivas,&nbsp;Carlos Bravo,&nbsp;María Magdalena Pulido","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>An experimental model of autoimmune myopathy was designed using parental antigens (muscle mitochondrial fraction) in F1 hybrid rats (male Wistar x female Sprague-Dawley). The immune response was modulated by spleen fragment transplant from either Wistar (W) or F1. Antibody fixation and inflammatory reaction were studied in Extensor digitorum longus and soleus muscles. Immunization without spleen transplant resulted in antibody fixation mainly in capillaries and incompletely around muscle fibers; whorled fibers were found in 1/3 of F1 rats immunized with antigen from W rats. Spleen transplants from Sprague Dawley (SD) rats were usually accepted by F1; in some animals, antibodies surrounded completely muscle fibers and the percentage of animals showing soleus muscle lesions was increased. Spleen transplants from non immunized F1 were usually rejected by immunized F1; antibody reaction was found inside fibers of most of the rats, muscle damage was present in 40% of the animals immunized with W, but absent in those immunized with SD antigen. In conclusion, this model can be used to study immunological responses to alloantigens (parental to F1). Spleen fragment transplant modulates the immune response. There was discrepancy between antibody fixation and muscle damage. The immunological response was different according to muscle fiber type composition and/or microcirculatory characteristics.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 4","pages":"290-6"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22552335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Morphology, anatomy and floral biology of Cabralea canjerana (Vell.) Mart. (Meliaceae)].","authors":"Ismar S Moscheta,&nbsp;Luiz A de Souza,&nbsp;Káthia S Mourão,&nbsp;Sônia M da Rosa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Cabralea canjerana (Vell.) Mart. is a tree that occurs frequently in secondary forests of Maringá, Paraná, Brazil and presents a valuable wood. Its flowering time occurs from August to October and the anthesis occurs during the night. Its flowers are visited by Lepidoptera-Noctuidae. The flowers are unisexual and solitary or arranged in panicles. The perianth presents a papillose epidermis with striate cuticle and a parenchymatic mesophyll. Ten stamens constitute the androecium and are arranged in a staminal tube with anthers. The anthers present epidermis, endothecium, two median layers and secretory tapetum with binucleate cells. The semi-inferior ovary presents anatropous, bitegmic and crassinucleate ovules. The nectaries are located in the base of the ovary and staminal tube and they present papillose epidermis with stomata and secretory parenchyma with a conspicuous phloematic tissue.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 4","pages":"239-44"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22552374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Immune response and anergy. Study in tuberculosis patients from the Universitary Hospital, Maracaibo, Venezuela ].","authors":"Milagros Montiel,&nbsp;Sergio Rivera,&nbsp;Rosaura Hernández,&nbsp;Manzur Hassanhi,&nbsp;Carmen Villalobos,&nbsp;Francisco Vargas,&nbsp;José Núñez","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>With the aim of evaluate the anergy in Mycobacterium tuberculosis individuals infected we study 57 patients and 15 healthy controls, both sex and with different age, which to practice Sputum Bacteriology culture (BK) and the la reaction intradermic with PDD. The test of tuberculine on skin was achieve inoculate 0.1 ml de PPD intradérmic vía, the results were obtained at 72 h. 28 patient total result BK+ and 29 BK-. The Group BK+, 15 result PPD+ and 13 PPD-, the lastet were classify as anergic patients (BK+ PPD-). From the 29 patient residual (BK-), 20 was PPD+ and 9 PPD-. All the controls resulted BK- PPD-. Only the anergy in patient BK was evaluated + (28 individuals) patient. Was classified from the point of clinical view in three series: N series: 27 patient TBC+ BK-, P Series: 28 patient TBC+ BK+ and EP Series: 2 patient with extra pulmonary TBC. According to the grade of pulmonary complication, the patient separated in two groups, according to the extension and type of lesion found in the evaluation with X. rays The \"group 1\" with 9 patient (32.14%) it introduced lesions on one side with or without caverns and the \"group 2\" with 19 patient (67.85%) with bilateral lesions with or without caverns. Was carried out the Lymphoblastic Transformation Test (TTL) stimulating with PHA and PPD, for which patterns of outlying blood with heparina were gathered. The concentrations of IL-4, IL-6 and INF-gamma was gotten inmunoenzimatic in supernatants of cultivations for rehearsals and in plasm, hind to the stimulation with the PPD. The statistical analysis was carried out utilizing the Test T of Student in pair, Varianza Analysis and the square Chi. Only the controls and the patient BK-, they showed normal response to the PHA, in contrast, the patient BK+ PPD+ they introduced a suppression of the response opposite the PHA of aprox. 90%. The patient PPD+ they showed a superior response in cultivation that the patient PPD-. The concentration of IL-4 in the plasm of the anergic patient (PPD-) showed a significant difference (P < 0.05) with concerning the PPD group+. The concentration of INF-gamma was lower in the anergic patient significantly different to the of the patient PPD+. Similar result was gotten in the mensuration of IL-4 and INF-gamma in supernatants of cultivation. One could observe the presence of patient with IL-4+ INF-gamma, and INF-gamma or IL-4 only. In the patient classified clinical like series \"P\", the concentration of IL-4 was old in the \"group 2\" with concerning the \"group 1.\" the opposite occurred with the concentrations of the INF-gamma which were old in the \"group 1\" (both differences were not significant statistical). The increase of IL-4 next to low concentrations of INF-gamma in anergic patient and committed clinical, it suggest a prevalence of the pattern Th2 (T2) in the immune response.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"53 1","pages":"36-43"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21977447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}