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[In vitro propagation of mahogany tree (Swietenia macrophylla King) from axillary buds]. [红木(Swietenia macrophylla King)腋芽离体繁殖的研究]。
Acta cientifica venezolana Pub Date : 2004-01-01
Melángel Tacoronte, María Vielma, Argenis Mora, Carle Valecillos
{"title":"[In vitro propagation of mahogany tree (Swietenia macrophylla King) from axillary buds].","authors":"Melángel Tacoronte,&nbsp;María Vielma,&nbsp;Argenis Mora,&nbsp;Carle Valecillos","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The mahogany tree (Swietenia macrophylla King) is a forest tree with a great commercial value mainly due to its wood quality. Unfortunately, this species is being threatened by the effect of intensive timber exploitation, its low capacity to regenerate, and the attack of the Meliaceae shoot borer (Hypsipylla grandella Zeller) (Lepidoptera Pyralidae). To increase population, large-scale propagation of mahogany by in vitro culture was developed. To obtain plantlets, nodal segments were cultured in a half-strength MS medium supplemented with different combinations of naphthaleneacetic acid (NAA) and 6-benzyladenine (BA), specified by the Central Compositional Rotable Statistical Design Method, within a range of 0-3 mg/L for both hormones. Favourable incubation conditions were: 16 h light, and 40-45 micromol x m(-2) x s(-1) at 25 degrees C. The derived response surface showed an optimal axillary bud elongation on a medium containing 1.94 mg BA/L and 0.38 mg NAA/L. No significant differences were found neither applying Orellana Method nor modified Orellana method. Mahogany plantlets obtained were successfully acclimated.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"7-12"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40930545","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}
引用次数: 0
[Obtention of human skin sheets by means of tissue engineering]. [组织工程技术对人体皮肤薄片的研究]。
Acta cientifica venezolana Pub Date : 2004-01-01
Francisco Arvelo, Pedro Pérez, Carlos Cotte
{"title":"[Obtention of human skin sheets by means of tissue engineering].","authors":"Francisco Arvelo,&nbsp;Pedro Pérez,&nbsp;Carlos Cotte","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The aim of this \"in vitro\" study was to develop a new system for keratinocyte culture on a dermal equivalent that enables treatment of different skin injuries. The keratinocyte where obtained from primary cell cultures derived from skin biopsies, seeded over a fibrin matrix enhanced with live human fibroblast. Cells growing over the dermal equivalent, rapidly confluences and a stratified epithelium was obtained within 20-25 days culture. Detachment of composite culture from flask is a simple and quick procedure with no need for chemical or enzyme treatments. The method described provides a number of advantages which include the large expansion of keratinocyte from the primary cell cultures without the need of a feeder layer, the availability of plasma from blood banks, and the versatile and safe manipulation of composite obtained \"in vitro\". All these facts allow to assure that this system could result very efficient for the treatment of all type of skin injuries.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"74-82"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931067","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}
引用次数: 0
[Reproductive structures of Piper amalago var. medium Linnaeus (Piperaceae)]. [花椒科中花椒的生殖结构]。
Acta cientifica venezolana Pub Date : 2004-01-01
Sônia M da Rosa, Luiz A de Souza
{"title":"[Reproductive structures of Piper amalago var. medium Linnaeus (Piperaceae)].","authors":"Sônia M da Rosa,&nbsp;Luiz A de Souza","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Flowers, fruits, seeds and subterranean organ of Piper amalago var. medium Linnaeus were analyzed structurally. Flowers are hermaphrodite lacking perianth, with two stamens and a tricarpelate gynoecea. Tetrasporangiate anthers shows epidermis, endothecium, one or two middle layers and secretory tapetum. Ovary has a simple structure, with ventral meristem. There is one orthotropous, bitegmic and crassinucellate ovule. Fruits are drupes. Seeds are endotegmic with copious perisperm. Putamen is composed of a sclerified inner mesocarp and endocarp. Individuals of the species can be interlinked by radicular subterranean organ, that can spread vegetatively.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"27-34"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931090","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}
引用次数: 0
[Yield of starch extraction from plantain (Musa paradisiaca). Pilot plant study]. 芭蕉淀粉提取率的研究[j]。试验工厂研究]。
Acta cientifica venezolana Pub Date : 2004-01-01
Emigdia Flores-Gorosquera, Francisco J García-Suárez, Emmanuel Flores-Huicochea, María C Núñez-Santiago, Rosalia A González-Soto, Luis A Bello-Pérez
{"title":"[Yield of starch extraction from plantain (Musa paradisiaca). Pilot plant study].","authors":"Emigdia Flores-Gorosquera,&nbsp;Francisco J García-Suárez,&nbsp;Emmanuel Flores-Huicochea,&nbsp;María C Núñez-Santiago,&nbsp;Rosalia A González-Soto,&nbsp;Luis A Bello-Pérez","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In México, the banana (Musa paradisiaca) is cooked (boiling or deep frying) before being eaten, but the consumption is not very popular and a big quantity of the product is lost after harvesting. The unripe plantain has a high level of starch and due to this the use of banana can be diversified as raw material for starch isolation. The objective of this work was to study the starch yield at pilot plant scale. Experiments at laboratory scale were carried out using the pulp with citric acid to 0,3 % (antioxidant), in order to evaluate the different unitary operations of the process. The starch yield, based on starch presence in the pulp that can be isolated, were between 76 and 86 %, and the values at pilot plant scale were between 63 and 71 %, in different lots of banana fruit. Starch yield values were similar among the diverse lots, showing that the process is reproducible. The lower values of starch recovery at pilot plant scale are due to the loss during sieving operations; however, the amount of starch recovery is good.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"86-90"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931069","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}
引用次数: 0
[Mollusks community associated to Thalassia testudinum (Bank et Köning 1805), in Mochima Bay, Venezuela]. [委内瑞拉Mochima湾与海棠(Thalassia testudinum, Bank et Köning 1805)有关的软体动物群落]。
Acta cientifica venezolana Pub Date : 2004-01-01
Oscar Díaz Díaz, Ildefonso Liñero-Arana
{"title":"[Mollusks community associated to Thalassia testudinum (Bank et Köning 1805), in Mochima Bay, Venezuela].","authors":"Oscar Díaz Díaz,&nbsp;Ildefonso Liñero-Arana","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>To study the community of mollusks associated to Thalassia testudinum, monthly samplings were made between January and December 2002 in four localities of the Bay of Mochima. A PVC corer, of 14.8 cm of diameter, was used for sampling; eight monthly replicates were taken in each locality. Each core was sifted in a sieve of 1mm of mesh opening, the mollusks were fixed in 8% formaldehide solution in sea water. 473 mollusks were analyzed and 40 species, belonging to 29 families, were identified. Mangle Quemao displayed the greater abundance, whereas Varadero the minor. Shannon-Weaver diversity average ranged between 2.02+/-0.43 bits.ind(-1) (Mangle Quemao) and 1.42+/-0.95 bits.ind(-1) (Toporo). ANOVA analysis showed significant differences in abundances of mollusks among localities.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"44-55"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931062","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}
引用次数: 0
[Synergistic antioxidative effect of vitamins E and C on low density lipoproteins from smokers and non-smokers subjects]. [维生素E和C对吸烟者和非吸烟者低密度脂蛋白的协同抗氧化作用]。
Acta cientifica venezolana Pub Date : 2004-01-01
Luz Barón, Eduardo Romero-Vecchione, Flor López, Rafael Apitz
{"title":"[Synergistic antioxidative effect of vitamins E and C on low density lipoproteins from smokers and non-smokers subjects].","authors":"Luz Barón,&nbsp;Eduardo Romero-Vecchione,&nbsp;Flor López,&nbsp;Rafael Apitz","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>LDL-lipids peroxidation is an important step in LDL atherogenicity. Tobacco smoke, promotes oxidative stress and reduces LDL-alfa tocoferol content and plasmatic vitamin C concentration. The objective of this double-blind randomized study was to assess the effect of vitamins E and C combined administration, on oxidative susceptibility of LDL isolated from 20 smokers and 10 non-smokers healthy volunteers who received placebo for 15 days and then concomitantly received 400 mg/d vitamin E and 1000 mg/d vitamin C for 30 days. At the end of placebo administration of and vitamins E and C combination; plasma total cholesterol, LDL-C and HDL-C values did not change significantly (p>0.05), plasma triglycerides increased significantly within a normal accepted range (p<0.05) and LDL oxidation susceptibility in smokers decreased by 41,3% and in non-smokers by 54,4% (p<0.05 vs placebo). In conclusion, simultaneous administration of vitamins E and C exerts an important antioxidant effect on LDL-lipids peroxidation. This effect could operate as an attenuating factor of the increased atherogenesis commonly observed in smoker subjects.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"62-73"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931066","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}
引用次数: 0
Determinant factors for an apparent increase in oxygen affinity of senescent human erythrocytes. 衰老人红细胞氧亲和力明显增加的决定因素。
Acta cientifica venezolana Pub Date : 2004-01-01
Pedro J Romero, Eneida A Romero
{"title":"Determinant factors for an apparent increase in oxygen affinity of senescent human erythrocytes.","authors":"Pedro J Romero,&nbsp;Eneida A Romero","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In the present work we have revaluated the old question of whether senescent human erythrocytes can handle oxygen delivery efficiently, by studying some factors determining haemoglobin-oxygen affinity of in vivo aged cells. Erythrocytes were separated according to their age using a novel approach for density gradient fractionation. The 5-10% least dense (young) and the heaviest (old) red cell fractions were separated by strict percoll density gradients under conditions inducing minimal cell stress, thus avoiding formation of aggregates. Aged cells showed a decreased content of organic phosphate compounds and additionally, an internal pH of about 0.2 pH units more alkaline than the younger cells. These results lend indirect experimental support for both an apparent increase in haemoglobin-oxygen affinity and a deficient oxygen release of in vivo aged human erythrocytes.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"83-5"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931068","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}
引用次数: 0
Characterization of free aromatic amino acids and estimation of exposition rate of phenylalanine in casein hydrolysates by second derivative spectrophotometry. 二阶导数分光光度法测定酪蛋白水解产物中游离芳香族氨基酸及苯丙氨酸暴露率。
Acta cientifica venezolana Pub Date : 2004-01-01
Harriman A Morais, Viviane D M Silva, Mônica C Oliveira, Marialice P C Silvestre
{"title":"Characterization of free aromatic amino acids and estimation of exposition rate of phenylalanine in casein hydrolysates by second derivative spectrophotometry.","authors":"Harriman A Morais,&nbsp;Viviane D M Silva,&nbsp;Mônica C Oliveira,&nbsp;Marialice P C Silvestre","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In this work, the second derivative spectrophotometry (SDS), a fast, simple and relatively low-cost method,-was used to characterize aromatic amino acids at two pH values (7 and 13) and to evaluate the exposition rate of Phe in casein hydrolysates prepared with papain. The results indicate that at 37 degrees C, pH 7.5 and an enzyme:substrate ratio of 4:100, for hydrolyzing casein by papain, the highest Phe exposition was observed. Therefore these are the most appropriate conditions for Phe removal and preparation of supplements for phenylketonurics. The use of SDS at pH 13.0 gives a good resolution of Tyr and Trp peaks. A similarity among SDS spectra of aromatic amino acids and protein hydrolysates, was also observed.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931210","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}
引用次数: 0
[Leaf anatomy of four species of Solanum L. section Acanthophora Dunal in Venezuela]. [委内瑞拉茄属(Solanum L.)棘棘属(Acanthophora Dunal)四种的叶片解剖]。
Acta cientifica venezolana Pub Date : 2004-01-01
William A Granada-Chacón, Carmen E Benítez de Rojas
{"title":"[Leaf anatomy of four species of Solanum L. section Acanthophora Dunal in Venezuela].","authors":"William A Granada-Chacón,&nbsp;Carmen E Benítez de Rojas","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Anatomical characteristics of S. acerifolium Dun., S. agrarium Sendtn., S. capsicoides All. and S. mammosum L., leaves were studied in order to recognize some useful features for its interspecific delimitation. 5 to 10 healthy fully expanded leaves, taken from the middle third of the plant, were examined in at least 3 different plants for each studied species. Samples were preserved in 70% FAA. Additionally, herbarium specimens (4-5 leaves/specimen) were hydrated in lactophenol and examined. The middle third of the foliar lamina and the petiole were prepared following the classical techniques used for anatomical studies. Clearing process of the foliar lamina was also made. The results show similar histological configuration in all studied species. Among the most remarkable features are: the type of leaf regarding to stomata location, number of petiole layers, angular collenchyma, petiole cross section shape and the type of vascular bundles. Finally, it is concluded that the anatomical study of the leaves of mentioned species is useful for its delimitation.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"13-26"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40930544","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}
引用次数: 0
[Nutritional condition and serum protein concentration in children (6-12 years old) of Chacopata Sucre State, Venezuela (December--January, 1997)]. [委内瑞拉Chacopata Sucre州6-12岁儿童的营养状况和血清蛋白浓度(1997年12月-1月)]。
Acta cientifica venezolana Pub Date : 2004-01-01
Solange Vásquez, Andrés Gerardi García, Raquel Salazar Lugo
{"title":"[Nutritional condition and serum protein concentration in children (6-12 years old) of Chacopata Sucre State, Venezuela (December--January, 1997)].","authors":"Solange Vásquez,&nbsp;Andrés Gerardi García,&nbsp;Raquel Salazar Lugo","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A biochemical and anthropometrical study of 175 children (6-12 years old) from Chacopata, Sucre State was done (December--January, 1997). The children were evaluated by combined anthropometrical indicators (OMS), clinical, nutritional and biochemical tests. The results showed 81.71% well-nourished children, 4.57% obese children and 13.72% with some degree of undernutrition: 3.43% acute undernourished and 10.29% chronic undernourished. Total seric proteins including fractions: albumin, alfa-1 alfa-2, beta and gamma globulins as well as total globulins and albumin/globulin indexes were at the normal reference range for children (6-12 years old). A significative increase in alfa-1 globulin (0.18+/-0.08 g/dl; 8-9 years old group) and decrease of alfa-2 globulin (0.71+/-0.11 g/dl; 10-12 year old group) was observed. Biochemical results associated with nutritional condition showed normal values, moreover, this biochemical index decreased in the undernourished group. A significant decrease of the seric beta globulin in the undernourished children (0.72+/-0,12 g/dl) with respect to the well-nourished children (0.79+/-0.15) was found. In children (6-12 years old) from Chacopata, compensated chronic undernourishement is prevalent.</p>","PeriodicalId":75378,"journal":{"name":"Acta cientifica venezolana","volume":"55 1","pages":"56-61"},"PeriodicalIF":0.0,"publicationDate":"2004-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40931063","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}
引用次数: 0
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