21 results on '"Paiva, C. L."'
Search Results
2. DNA replication in bacteriophage T1 : The roles of genes 3.5, 4 and das
- Author
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Paiva, C. L. A.
- Subjects
572.8 ,Genetics - Published
- 1986
3. Acceptability and study of shelf life of gluten free cereal bar with popped and extruded sorghum based on a consumer acceptability
- Author
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PAIVA, C. L., QUEIROZ, V. A. V., GARCIA, M. A. V. T., CARVALHO, C. W. P. de, Caroline Liboreiro Paiva, Universidade Federal de Minas Gerais, VALERIA APARECIDA VIEIRA QUEIROZ, CNPMS, Maria Aparecida Vieira Teixeira Garcia, Universidade Federal de Minas Gerais, and CARLOS WANDERLEI PILER DE CARVALHO, CTAA.
- Subjects
Sorghum Bicolor ,Composição Química ,Glúten ,Alimento ,Cereal ,Celíaco - Abstract
Cereal bars have been an excellent vehicle for delivering functional ingredients to food market. Researches has showed that sorghum is a great source of phenolic compounds. Besides, it is a gluten free cereal, therefore a potential ingredient to celiac diets. Thus, a cereal bar with popped sorghum, sorghum extrudates, cashew fiber and dehydrated banana was formulated. Sensory acceptability of this product was determined by two panels: one panel composed of celiac individuals and another by non-celiac subjects. The product shelf life was estimated by the acceptability limit methodology. After remained stored for 120 days under 25°C, the shelf life was estimated at 163 ± 52 days. The sensorial study has not found significant differences in relation to overall acceptability between celiac and non-celiac individuals. This study suggest that sorghum co-products could be used successfully as a food ingredient to develop new formulations of the gluten free cereal bars. Made available in DSpace on 2018-09-05T00:36:54Z (GMT). No. of bitstreams: 1 Acceptabilitystudy.pdf: 452110 bytes, checksum: 08d597aa384b8c4c864674ac5834ff66 (MD5) Previous issue date: 2018-09-04
- Published
- 2018
4. Retention of some flavones and flavanones in flour, grain and bran of sorghum during storage
- Author
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QUEIROZ, V. A. V., OLIVEIRA, K. G. de, PAIVA, C. L., CARLOS, L. de A., MENEZES, C. B. de, BARROS, F. A. R. de, PINHEIRO-SANT'ANA, H. M., ANUNCIAÇÃO, P. C., VALERIA APARECIDA VIEIRA QUEIROZ, CNPMS, KÊNIA GRASIELLE DE OLIVEIRA, Universidade Federal de São João del- Rei, CAROLINE LIBOREIRO PAIVA, Universidade Federal de Minas Gerais, LANAMAR DE ALMEIDA CARLOS, Universidade Federal de São João del- Rei, CICERO BESERRA DE MENEZES, CNPMS, FREDERICO AUGUSTO RIBEIRO DE BARROS, Universidade Federal de Viçosa, HELENA MARIA PINHEIRO SANT'ANA, Universidade Federal de Viçosa, and PAMELLA CRISTINE ANUNCIAÇÃO, Universidade Federal de Viçosa.
- Subjects
Sorghum Bicolor ,Flavonóide ,Perda ,Armazenamento - Abstract
O sorgo está associado a várias propriedades funcionais pelo fato de conter altos níveis de compostos fenólicos, como flavonoides, flavonas e flavanonas. No entanto, estes compostos são sensíveis ao período e condições de armazenamento. Assim, este trabalho teve como objetivo avaliar a retenção de luteolina, apigenina, naringenina e eriodictilol nos genótipos de sorgo SC319 (farinha e grão) e TX430 (farinha e farelo) armazenados por 180 dias a 4, 25 e 40 °C. Estes compostos foram quantificados por cromatografia líquida de alto desempenho acoplada a detector de arranjo de diodos. Houve efeito do tempo de armazenamento, que favoreceu a redução de flavona e flavanona nos genótipos avaliados. A temperatura de armazenamento influenciou as flavonas mais do que o conteúdo de flavanona. As retenções variaram de 70,27 a 88,72% para luteolina, 69,04 a 99,15% para apigenina, 56,92 a 88,51% para naringenina e de 77,10 a 93,42% para eriodictilol nas três temperaturas no final de 180 dias. Embora as flavonas e flavanonas tenham sido melhor conservadas a 4 °C (cerca de 88% de retenção), em temperatura ambiente (25 °C), as retenções de flavonas e flavanonas foram pelo menos 77% e 85% após 180 dias. Made available in DSpace on 2019-01-11T00:07:26Z (GMT). No. of bitstreams: 1 Retentionsome.pdf: 815232 bytes, checksum: 70dc7db822f68e59f1177829851ce142 (MD5) Previous issue date: 2019-01-09
- Published
- 2018
5. ESTUDO TERMODINÂMICO DE MISTURAS DE ETANOL E IGEPAL (CO-520 E CO-720): PROPRIEDADES VOLUMÉTRICAS E DE TRANSPORTE
- Author
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PAIVA, C. L., additional, PINHEIRO, R. S., additional, de SANT'ANA, H. B., additional, and FEITOSA, F. X., additional
- Published
- 2018
- Full Text
- View/download PDF
6. Diversidade genética de espécies do gênero Passiflora com o uso da estratégia Ward-MLM
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PAIVA, C. L., VIANA, A. P., SANTOS, E. A., SILVA, R. N. O. A, OLIVEIRA, E. J. de, CLAUDIA LOUGON PAIVA, UNEF, ALEXANDRE PIO VIANA, UNEF, EILEEN AZEVEDO SANTOS, UNEF, RAIMUNDO NONATO OLIVEIRA SILVA, UNEF, and EDER JORGE DE OLIVEIRA, CNPMF.
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Passiflora ,Maracujá ,Genetic resources ,Recursdo genético ,Passion fruits - Abstract
O uso de espécies silvestres de maracujá tem resultado em progresso no melhoramento genético da cultura. No entanto, o uso dessas tem sido incipiente, devido à existência de poucas informações sobre a diversidade genética disponível. Tais atividades são essenciais para que os recursos genéticos do gênero Passiflora sejam utilizados com sucesso. Este trabalho objetivou quantificar a diversidade genética existente entre onze espécies do gênero Passiflora (Passiflora edulis, P. mucronata, P. setacea, P. pentagona, P. caerulea, P. gibertii, P. cincinnata, P. suberosa, P. micropetala, P. alata e P.coccinea). Foram utilizados descritores morfológicos qualitativos e quantitativos, sendo analisados conjuntamente por meio do procedimento Ward-MLM (Modified Location Model). Os acessos foram reunidos em cinco grandes grupos, sendo os caracteres relacionados às flores os que mais contribuíram para a diversidade genética dos acessos. O método de Ward-MLM possibilitou distinguir os subgêneros analisados, e houve uma clara separação entre as espécies. Vasta diversidade foi encontrada no gênero Passiflora, que pode ser explorada em programas de melhoramento do maracujazeiro.
- Published
- 2014
7. Gonadotrophin-releasing hormone immunoreactivity in the brain of the tropical freshwater fish, Pygocentrus notatus (Teleostei-Characidae)
- Author
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Cacares-Dittmar, G., Felix J. Tapia, Guerrero, H. Y., Paiva, C. L., and Marcano, D.
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endocrine system ,6 - Ciencias aplicadas::61 - Medicina [CDU] ,nervous system ,Hypothalamus ,Immunohistochemistry ,hormones, hormone substitutes, and hormone antagonists - Abstract
The distribution of GnRH in the brain of the teleost Pygocentrus notatus was demonstrated with the avidin-biotin peroxidase immunocytochemical method using highly specific antibody against synthetic mammalian GnRH. Optimal immunoreaction was obtained using: 1) Bouin's fluid for fixation; 2) repeated incubation with primary antiserum; 3) the use of a detergent in the dilution buffer; 4) the high sensitivity of the avidin-biotin immunoperoxidase method with the cobalt intensification of 3-3'diaminobenzidine tetrahydrochloride; and 5) the use of primary antibody with high specificity. GnRH-immunoreactive (GnRH-ir) in cells andlor axons was observed in al1 main brain regions. In the forebrain, GnRH-ir was located in a network extending from the caudal part of the olfactory bulb to the telencephalon. GnRH-ir fibres were also observed in the optic tectum, cerebellum and hypothalamus. Two groups of neurona1 cell bodies were identified. One group was located in the antero-ventral telencephalon corresponding to the nucleus olfactoretinalis. The second group was found in the rostrodorsal hypothalamus. No GnRH-ir material was detected in the pituitary gland, thus confirming the results of previous studies on brain GnRH-ir distribution obtained by radioimmunoanalysis in this species. These results demonstrate a high degree of similarity between the GnRH systems of P. notatus and other teleost species.
- Published
- 1993
8. Chemical characterization of baru oil and its by-product from the northwest region of Minas Gerais, Brazil.
- Author
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Borges, L. A., Souto, R. N. B., Nascimento, A. L. A., Soares, J. F., Paiva, C. L., Brandi, I. V., and Lima, J. P.
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CERRADO plants , *AGRICULTURAL wastes , *CHEMICAL composition of plants , *MINERAL content of food , *WASTE products , *PLANT diversity , *UNSATURATED fatty acids , *CAROTENOIDS , *NUTRITIONAL value , *HIGH performance liquid chromatography , *NUTRITION , *PETROLEUM - Abstract
This study investigated baru oil and partially defatted baru flour from the northwest region of Minas Gerais, Brazil. The physicochemical characterization of the oil was made by determining the fatty acid profile using gas chromatography, lutein, and α- and β-carotenes by means of high-performance liquid chromatography, and total carotenoids by spectrophotometry. The flour was analyzed for its chemical composition, fiber, and mineral contents. Baru oil presented excellent quality parameters and high contents in unsaturated fatty acids and carotenoids. The flour showed relevant levels of proteins, lipids, and dietary fiber, in addition to having representative mineral contents for food such as manganese, magnesium, and copper. Thus, baru oil and the by-product of its extraction offer a rich chemical composition, and their application may add nutritional value to foods in addition to reducing negative environmental impacts. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. REVIEW-ARTICLE Intermediate alleles of Huntington's disease HTT gene in different populations worldwide: a systematic review.
- Author
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Apolinário TA, Paiva CL, and Agostinho LA
- Subjects
- Alleles, Brazil, Gene Frequency, Genetic Association Studies, Haplotypes, Humans, Huntingtin Protein metabolism, Huntington Disease epidemiology, Mutation, Trinucleotide Repeat Expansion, Huntingtin Protein genetics, Huntington Disease genetics
- Abstract
Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder caused by a dynamic mutation due to the expansion of CAG repeats in the HTT gene (4p16.3). The considered normal alleles have less than 27 CAG repeats. Intermediate alleles (IAs) show 27 to 35 CAG repeats and expanded alleles have more than 35 repeats. The IAs apparently have shown a normal phenotype. However, there are some reported associations between individuals that bear an IA and clinical HD signs, such as behavioral disturbs. The association of IAs with the presence of clinical signs gives clinical relevance to these patients. We emphasized the importance of determining the frequency of IA alleles in the general population as well as in HD families. Therefore, the aim of this study was to conduct a systematic review, in order to investigate the frequency of IAs in the overall chromosomes of different ethnic groups and of families with HD history worldwide as well as the frequency of individuals who bear the intermediate alleles. We searched indexed articles from the following electronic databases: U.S. National Library of Medicine and the National Institutes of Health (PubMed), Pubmed Central (PMC) and Virtual Health Library (VHL). Therefore, 488 articles were obtained and, of these, 33 had been published in more than one database. We accepted the article of only one database and ended up with 455 articles for this review. The frequency of IAs within the chromosomes of the general population ranged from 0.45 to 8.7% and of individuals with family history of HD ranged from 0.05 to 5.1%. The higher frequency of IAs in the general population (8.7%) was found in one Brazilian cohort.
- Published
- 2017
- Full Text
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10. Notification of Huntington's disease as primary cause of death in Brazil from 1984 to 2008.
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Vaz IP and Paiva CL
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- Brazil epidemiology, Cause of Death, Databases, Factual, Female, Humans, Huntington Disease epidemiology, Linear Models, Male, Retrospective Studies, Huntington Disease mortality
- Abstract
The aim of this article was to conduct a retrospective observational study on reported deaths due to Huntington's disease (HD) in Brazil in the past 25 years (from 1984 to 2008). Data were obtained from the Brazilian Mortality Information System (SIM/DATASUS), the official system of Brazilian Mortality Database. The data obtained included information regarding the gender of the deceased and the number of death notifications, which we stratified by demographic regions and states. HD mortality per 100,000 was calculated and plotted in a graph. Linear regression was calculated using ordinary least square technique. We observed that the mortality due to HD recorded by SIM/DATASUS from 1984 to 2008 had increased at much higher rates than the population in the same period. Also, some Brazilian regions still show very low rates of HD mortality compared to the national average of deaths due to HD. These findings suggest that HD mortality has been underestimated. Ignorance about the disease as well as the fact that death from HD can occur as a consequence of heart disease, pneumonia, or suicide can strongly contribute to the misguided notification of HD as the cause of death in the official reports.
- Published
- 2016
- Full Text
- View/download PDF
11. Clinical and genetic investigation of a Brazilian family with Huntington's disease.
- Author
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Agostinho LA, Spitz M, Pereira JS, and Paiva CL
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- Adult, Aged, Brazil, Cross-Sectional Studies, Female, Genetic Association Studies, Genotype, Humans, Male, Mental Status Schedule, Middle Aged, Severity of Illness Index, Family Health, Huntingtin Protein genetics, Huntington Disease diagnosis, Huntington Disease genetics, Trinucleotide Repeats genetics
- Abstract
The aim of this study was to investigate a Brazilian family carrying full penetrance alleles for Huntington's disease (HD) in order to correlate each member's genetic and clinical features. To this end, the following scales were administered in each patient: the Beck Depression Inventory, the Mini-Mental State Examination (MMSE) and the Unified Huntington's Disease Rating Scale (UHDRS). The patterns of CAG and CCG polymorphic regions in the HTT gene were determined, the disease burden score was calculated, and genotypes were correlated with phenotypes within this family. We suggest that HD duration, the number of years of formal education, and UHDRS status variables can explain 96.6% of the MMSE variability in HD patients. A strong significant correlation was found between the disease burden score and the UHDRS (r = 0.76; p-value = 0.049) and the MMSE (r = -0.90; p-value = 0.006). The correlations between CAG allele size and the three clinical evaluations performed in the HD patients were not statistically significant.
- Published
- 2016
- Full Text
- View/download PDF
12. Mini-Review: Monosomy 1p36 syndrome: reviewing the correlation between deletion sizes and phenotypes.
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Rocha CF, Vasques RB, Santos SR, and Paiva CL
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- Adolescent, Child, Child, Preschool, Chromosome Disorders diagnosis, Chromosomes, Human, Pair 1 genetics, Female, Humans, Infant, Infant, Newborn, Male, Young Adult, Chromosome Deletion, Chromosome Disorders genetics, Phenotype
- Abstract
The major clinical features of monosomy 1p36 deletion are developmental delay and hypotonia associated with short stature and craniofacial dysmorphisms. The objective of this study was to review the cases of 1p36 deletion that was reported between 1999 and 2014, in order to identify a possible correlation between the size of the 1p36-deleted segment and the clinical phenotype of the disease. Scientific articles published in the (National Center for Biotechnology Information; NCBI http://www.ncbi.nlm.nih.gov/pubmed) and Scientific Electronic Library Online (www.scielo.com.br) databases were searched using key word combinations, such as "1p36 deletion", "monosomy 1p36 deletion", and "1p36 deletion syndrome". Articles in English or Spanish reporting the correlation between deletion sizes and the respective clinical phenotypes were retrieved, while letters, reviews, guidelines, and studies with mouse models were excluded. Among the 746 retrieved articles, only 17 (12 case reports and 5 series of cases), comprising 29 patients (9 males and 20 females, aged 0 months (neonate) to 22 years) bearing the 1p36 deletions and whose clinical phenotypes were described, met the inclusion criteria. The genotype-phenotype correlation in monosomy 1p36 is a challenge because of the variability in the size of the deleted segment, as well as in the clinical manifestations of similar size deletions. Therefore, the severity of the clinical features was not always associated with the deletion size, possibly because of the other influences, such as stochastic factors, epigenetic events, or reduced penetration of the deleted genes.
- Published
- 2016
- Full Text
- View/download PDF
13. Phenotyping of Passiflora edulis, P. setacea, and their hybrids by a multivariate approach.
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Santos EA, Viana AP, Freitas JC, Souza MM, Paiva CL, Rodrigues DL, and Tavares RF
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- Crosses, Genetic, Flowers anatomy & histology, Flowers genetics, Fruit anatomy & histology, Fruit genetics, Genotype, Likelihood Functions, Multivariate Analysis, Phenotype, Quantitative Trait, Heritable, Species Specificity, Hybridization, Genetic, Passiflora anatomy & histology, Passiflora genetics
- Abstract
Morphological characterization is the most accessible and used method to quantify the genetic diversity of the available germplasm. The multivariate statistical method is highly important for this purpose. This study aimed to characterize parents and hybrids of Passiflora according to morphoagronomic descriptors and estimate the genetic divergence between them based on the joint analysis of qualitative and quantitative variables using the Ward-modified location model (MLM) procedure. One hundred and thirty-eight individuals were assessed (10 P. edulis, 10 P. setacea, and 118 interspecific hybrids) using 23 quantitative and 12 qualitative descriptors. The values for the quantitative descriptors were measured and subjected to multivariate statistics using the Ward-MLM strategy. Large genetic variability was detected by the morphoagronomic data in the 138 genotypes that were evaluated, and the hybrids presented higher variability than the parents. Pseudo-F and pseudo-t2 criteria showed that the optimal number of groups was three. Group I was composed of 118 hybrid genotypes; group II was composed of the 10 P. setacea genotypes, and group III was composed of the 10 P. edulis genotypes. The longest distance was found between groups II and III (474.96). The shortest distance was detected between groups I and II (198.78), which indicates that the segregating population is genetically closer to P. setacea than to P. edulis. The Ward-MLM procedure is a useful tool to detect genetic diversity and group accessions using both qualitative and quantitative variables.
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- 2014
- Full Text
- View/download PDF
14. Prader-Willi-like phenotypes: a systematic review of their chromosomal abnormalities.
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Rocha CF and Paiva CL
- Subjects
- Diagnosis, Differential, Female, Humans, Male, Chromosome Aberrations, Phenotype, Prader-Willi Syndrome diagnosis, Prader-Willi Syndrome genetics
- Abstract
Prader-Willi syndrome (PWS) is caused by the lack of expression of genes located on paternal chromosome 15q11-q13. This lack of gene expression may be due to a deletion in this chromosomal segment, to maternal uniparental disomy of chromosome 15, or to a defect in the imprinting center on 15q11-q13. PWS is characterized by hypotonia during the neonatal stage and in childhood, accompanied by a delay in neuropsychomotor development. Overeating, obesity, and mental deficiency arise later on. The syndrome has a clinical overlap with other diseases, which makes it difficult to accurately diagnose. The purpose of this article is to review the Prader-Willi-like phenotype in the scientific literature from 2000 to 2013, i.e., to review the cases of PWS caused by chromosomal abnormalities different from those found on chromosome 15. A search was carried out using the "National Center for Biotechnology Information" (www.pubmed.com) and "Scientific Electronic Library Online (www.scielo.br) databases and combinations of key words such as "Prader-Willi-like phenotype" and "Prader-Willi syndrome phenotype". Editorials, letters, reviews, and guidelines were excluded. Articles chosen contained descriptions of patients diagnosed with the PWS phenotype but who were negative for alterations on 15q11-q13. Our search found 643 articles about PWS, but only 14 of these matched with the Prader-Willi-like phenotype and with the selected years of publication (2000-2013). If two or more articles reported the same chromosomal alterations for Prader-Willi-like phenotype, the most recent was chosen. Twelve articles of 14 were case reports and 2 reported series of cases.
- Published
- 2014
- Full Text
- View/download PDF
15. A systematic review of the intergenerational aspects and the diverse genetic profiles of Huntington's disease.
- Author
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Agostinho LA, Dos Santos SR, Alvarenga RM, and Paiva CL
- Subjects
- Alleles, Americas epidemiology, Asian People genetics, Asian People statistics & numerical data, Chromosomes, Human, Pair 4, Europe epidemiology, Humans, Huntingtin Protein, Huntington Disease ethnology, Nerve Tissue Proteins metabolism, Trinucleotide Repeat Expansion, Turkey epidemiology, White People genetics, White People statistics & numerical data, Huntington Disease epidemiology, Huntington Disease genetics, Nerve Tissue Proteins genetics
- Abstract
Huntington's disease (HD) is a rare progressive and fatal neurogenetic degenerative disease, characterized by movement and personality disorders and by progressive dementia. Its prevalence varies by ethnic origin and different genetic profiles predisposing individuals to HD in each population. The prevalence of HD is 5-10 per 100,000 individuals in Caucasian populations of North America and Western Europe. It is an autosomal dominant disease associated with the expansion of CAG-type repetitive DNA sequences in the HTT gene. This gene, located on the short arm of chromosome 4, encodes the protein huntingtin. In this study, we reviewed 17 articles about HD that report data from 2400 affected individuals from various countries around the world, including Venezuela, China, Croatia, Turkey, Germany, Italy, Brazil, Spain, Taiwan, India, the Netherlands, Russia, and the USA, with a focus on genetic profiles and intergenerational expansions or contractions of expanded alleles responsible for causing HD. We discuss the genetic characteristics of HD in different populations and any atypical cases reported in these studies.
- Published
- 2013
- Full Text
- View/download PDF
16. Trehalase immobilization on aminopropyl glass for analytical use.
- Author
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Bachinski N, Martins AS, Paschoalin VM, Panek AD, and Paiva CL
- Abstract
Trehalase is the enzyme which hydrolyzes the disaccharide trehalose into two alpha-D-glucose molecules. In this article, we present the immobilization of trehalase on aminopropyl glass particles. The enzyme was extracted from Escherichia coli Mph2, a strain harboring the pTRE11 plasmid, which contains the trehalase gene. The partially purified enzyme had a specific activity of 356 U/mg and could be used for quantifying trehalose in the presence of sucrose, maltose, lactose, starch, and glycogen. Partially purified trehalase was immobilized by covalent coupling with retention of its catalytic activity. The support chosen for the majority of the experiments reported was aminopropyl glass, although spherisorb-5NH(2) and chitin were also tested. The immobilized enzyme was assayed continuously for 40 h, at pH 6.0 and 30 degrees C, and no release of enzyme molecules was detected during this procedure. The best condition found for storing the enzyme-support complex was at 4 degrees C in the presence of 25 mM sodium maleate, containing 7 mM beta-mercaptoethanol, 1 mM ethylenediaminetetraacetic acid (EDTA), and 50% glycerol. The enzyme under these conditions was stable, retaining approximately 100% of its initial activity for at least 28 days. The immobilized enzyme can be employed to detect trehalose molecules in micromolar concentration. The optimum pH value found was 4.5 and the K(m) app. 4.9 x 10(-3) M trehalose at pH 4.6 and 30 degrees C, with V(max) of 5.88 micromol glucose x min x(-1), as calculated by a Lineweaver-Burk plot.
- Published
- 1997
- Full Text
- View/download PDF
17. Biotechnological applications of the disaccharide trehalose.
- Author
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Paiva CL and Panek AD
- Subjects
- Biotechnology, Trehalase metabolism, Trehalose metabolism
- Abstract
Trehalose is a disaccharide present in a variety of anhydrobiotic organisms which have the ability to promptly resume their metabolism after addition of water. It has been successfully used as a nontoxic cryoprotectant of enzymes, membranes, vaccines, animal and plant cells and organs for surgical transplants. It has been predicted that trehalose can also be used as an ingredient for dried and processed food. Therefore, the recent biotechnological applications of trehalose have imposed the standardization of methods for its production, as well as for its specific quantification.
- Published
- 1996
- Full Text
- View/download PDF
18. Nylon-6 cylinders and a sponge-like derivative as supports for immobilizing trypsin.
- Author
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Bachinski N, Panek AD, and Paiva CL
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- Caprolactam chemistry, Caseins metabolism, Glutaral metabolism, Microscopy, Electron, Scanning, Time Factors, Caprolactam analogs & derivatives, Enzymes, Immobilized, Polymers chemistry, Trypsin metabolism
- Abstract
1. Two types of nylon-6 supports (small cylinders and a sponge-like derivative) were prepared for immobilizing enzymes. Nylon-6 beads were solubilized by immersion in 80% formic acid and then reprecipitated using two different types of non-solvent solutions (distilled water or a 1:1 acetone:water solution) giving rise to a sponge-like derivative and to a colloidal suspension, respectively. The latter was molded into a thin thread which was cut into small cylinders. 2. Trypsin (EC 3.4.21.4) was covalently bound to glutaraldehyde-activated nylon-6 cylinders as well as to the sponge-like derivative. The maximum (100%) apparent initial enzymatic activity was found for the trypsin bound to small cylinders, while the initial activity of trypsin bound to the sponge-like material was 61% in comparison with that of trypsin-small cylinders, under the same conditions of enzyme immobilization reaction (1 g of nylon support and 5 ml of 1.3 mg/ml trypsin in 0.1 M sodium phosphate buffer, pH 8.5, at 10 degrees C for 18 h) and of enzymatic reaction (1 g of trypsin-nylon in a batch reactor, 2 ml of 0.7% w/v azocasein solution in 50 mM borate buffer, pH 8.5, at 37 degrees C, with shaking, for 1 h). However, the decrease of activity after enzyme immobilization was more conspicuous for the trypsin-small cylinders than for the trypsin-sponge. The former retained approximately 25% of its initial activity, while the latter retained approximately 67% of its initial activity, after seven cycles of utilization for 1 h, pH 8.5, at 37 degrees C and 8 days of storage, pH 8.5, at 4 degrees C in the presence of azocasein. 3. Scanning electron microscopy was performed to visualize the surface of the support after each step of the immobilization process. The electron micrographs show that the two types of nylon supports had a rough surface, which became rougher and full of craters after treatment with 5 N HCl. On the other hand, the partially hydrolyzed nylon surface acquired the appearance of Swiss cheese after treatment with 2.5% glutaraldehyde. After reaction with the enzyme molecules the surface became rougher again.
- Published
- 1994
19. Periplasmic trehalase from Escherichia coli--characterization and immobilization on spherisorb.
- Author
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Tourinho-dos-Santos CF, Bachinski N, Paschoalin VM, Paiva CL, Silva JT, and Panek AD
- Subjects
- Electrophoresis, Polyacrylamide Gel methods, Enzyme Activation, Enzymes, Immobilized metabolism, Hot Temperature, Silica Gel, Silicon Dioxide, Time Factors, Trehalase metabolism, Trehalose analysis, Enzymes, Immobilized isolation & purification, Escherichia coli enzymology, Trehalase isolation & purification
- Abstract
1. Trehalase was partially purified from Escherichia coli and characterized. The Km for trehalose was 0.78 mM, the pH optimum 5.5 and the temperature optimum 30 degrees C. 2. Trehalase represented approximately 50% of the total protein released by osmotic shock. The preparation was free of nonspecific carbohydrate hydrolases, which act on sucrose, galactose and maltose, permitting trehalose determination in biological samples, such as insect hemolymph and free cell extracts among others. 3. The enzyme was stable in 50 mM maleate buffer, pH 6.2, at -8 degrees C for at least 6 months and could be used to determine trehalose in the range of 6 to 30 nmol. 4. Immobilization of the enzyme was achieved by covalent linkage to spherisorb-5NH2 (spherical silica gel). Retention of total catalytic activity averaged 32%. 5. The reactor, stored for one month at -5 degrees C, retained 98% of its initial immobilized activity. 6. This immobilized form of the enzyme could be used routinely for specific determinations of trehalose.
- Published
- 1994
20. Gonadotrophin-releasing hormone immunoreactivity in the brain of the tropical freshwater fish, Pygocentrus notatus (Teleostei-Characidae).
- Author
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Cáceres-Dittmar G, Tapia FJ, Guerrero HY, Paiva CL, and Marcano D
- Subjects
- Animals, Brain immunology, Brain Chemistry physiology, Female, Gonadotropin-Releasing Hormone immunology, Immunoenzyme Techniques, Immunohistochemistry, Male, Nerve Fibers immunology, Nerve Fibers metabolism, Pituitary Gland anatomy & histology, Pituitary Gland immunology, Pituitary Gland metabolism, Tissue Fixation, Brain anatomy & histology, Fishes metabolism, Gonadotropin-Releasing Hormone metabolism
- Abstract
The distribution of GnRH in the brain of the teleost Pygocentrus notatus was demonstrated with the avidin-biotin peroxidase immunocytochemical method using highly specific antibody against synthetic mammalian GnRH. Optimal immunoreaction was obtained using: 1) Bouin's fluid for fixation; 2) repeated incubation with primary antiserum; 3) the use of a detergent in the dilution buffer; 4) the high sensitivity of the avidin-biotin immunoperoxidase method with the cobalt intensification of 3-3' diaminobenzidine tetrahydrochloride; and 5) the use of primary antibody with high specificity. GnRH-immunoreactive (GnRH-ir) in cells and/or axons was observed in all main brain regions. In the forebrain, GnRH-ir was located in a network extending from the caudal part of the olfactory bulb to the telencephalon. GnRH-ir fibres were also observed in the optic tectum, cerebellum and hypothalamus. Two groups of neuronal cell bodies were identified. One group was located in the antero-ventral telencephalon corresponding to the nucleus olfactoretinalis. The second group was found in the rostrodorsal hypothalamus. No GnRH-ir material was detected in the pituitary gland, thus confirming the results of previous studies on brain GnRH-ir distribution obtained by radioimmunoanalysis in this species. These results demonstrate a high degree of similarity between the GnRH systems of P. notatus and other teleost species.
- Published
- 1993
21. Hypothalamic and telencephalic catecholamine content in the brain of the teleost fish, Pygocentrus notatus, during the annual reproductive cycle.
- Author
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Guerrero HY, Caceres G, Paiva CL, and Marcano D
- Subjects
- Animals, Chromatography, High Pressure Liquid, Dopamine metabolism, Epinephrine metabolism, Female, Male, Norepinephrine metabolism, Ovary growth & development, Reproduction physiology, Seasons, Testis growth & development, Catecholamines metabolism, Fishes physiology, Hypothalamus metabolism, Periodicity, Telencephalon metabolism
- Abstract
The catecholamines noradrenaline (NA), dopamine (DA), and adrenaline (A) were measured in hypothalamic and telencephalic extracts of the Venezuelan freshwater fish "caribe colorado," Pygocentrus notatus, at different stages of the reproductive cycle. The concentration of NA was found to be significantly higher in the telencephalon than in the hypothalamus, but that of DA was higher in the hypothalamus than in the telencephalon. Fluctuations depending upon the reproductive stage and environmental conditions occurred in both hypothalamus and telencephalon. In the hypothalamus, DA content was highest during the prespawning period (June) as compared to other periods of the cycle. Although the NA concentration was reduced during spawning there was no significant variation during any other period. DA concentrations in both telencephalon and hypothalamus showed a similar pattern of changes. In the telencephalon, NA levels increased between preparatory and prespawning periods but decreased sharply during spawning. No sex differences were observed in either area at any stage of reproduction.
- Published
- 1990
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