β‐d‐Xylosidase production was maximal for Humicola grisea var. thermoidea grown on xylan as the sole carbon source. The main β‐d‐xylosidase activity was localised in the periplasm. β‐Xylosidase was purified from crude extracts by heat treatment, ammonium sulfate precipitation and chromatography on DEAE‐cellulose and Sephadex G‐100. The purified enzyme was a monomer of molecular mass estimated to be 43 kDa by SDS‐PAGE and gel filtration. Optima of pH and temperature were 6.0 and 50 °C, respectively. The enzyme activity was stimulated by Ca2+, Fe2+, and Mg2+. The purified β‐xylosidase did not exhibit xylanase, carboxymethylcelullase, galactosidase, glucosidase, fucosidase or arabinosidase activities. The purified β‐xylosidase hydrolysed xylobiose and xylo‐oligosaccharides of up to five monosaccharide units. The enzyme had a Km of 0.49 mM for p‐nitrophenyl‐β‐d‐xylopyranoside and was not inhibited by its product, xylose.
RESUMOOs diferentes cursos oferecidos na área de saúde na Universidade, recebem a cada semestre um grande número de alunos, originários de diferentes escolas de ensino médio e, cursos pré-vestibulares. A capacidade cognitiva e de abstração de cada aluno, bem como o grau de conhecimento prévio relativo à área, são fatores que geram diferenças individuais dentro de um mesmo grupo. Em algumas disciplinas do ciclo básico, que são comuns a vários cursos da área da saúde, e que estão inseridas no currículo nos primeiros semestres dos cursos de graduação, conhecimentos prévios são de fundamental importância para o desenvolvimento do conteúdo programático teórico e prático da disciplina. A Bioquímica é um exemplo de disciplina do ciclo básico que é oferecida em praticamente todos os cursos da área da Saúde e que requer principalmente noções de Química e Biologia celular. Entretanto, o conhecimento de um determinado grupo de alunos é bastante heterogêneo, o que exige do professor de Bioquímica, a criação de um ambiente que estimule a aplicação prática do que está sendo abordado no âmbito da disciplina. Este artigo discute os resultados de uma pesquisa realizada com alunos ingressantes na disciplina de Bioquímica de cursos de graduação da Fundação Universidade Regional de Blumenau-FURB, com o intuito de avaliar o grau de conhecimento prévio. ABSTRACTThe different courses offered by the health area at University receive each semester a great number of students, from different high schools and pre-entry examination courses. The cognitive and abstraction capacity of each student, as well as the degree of relative previous knowledge to the area, are factors that generate individual differ ences inside a same group. In some disciplines of the basic cycle, which are common to several courses of the area of the health, and that are inserted in the curriculum in the first semesters of the graduation courses, previous knowledge are of fundamental importance for the development of the theoretical programmatic content and practice of the discipline. The Biochemistry is a discipline from the basic cycle that is offered in practically all of the health area courses, and requires mostly Chemistry notions and Cellular Biology. However, the knowledge sometimes acquired of a students certain group is a lot heterogeneous, what it demands of the Biochemistry teacher, the cre ation of an environment that stimulates the practice application than is being boarded in the scope of the discipline. This work argues the results of a research realized to the ingressants students in the Biochemistry discipline of the graduation courses of the Regional University Foundation of Blumenau -FURB, with the aim of evaluating the degree of previous knowledge.Endereço para contato: Rua Antônio da Veiga, 140 -Victor Konder -CP 1507 -CEP 89012-900 -Blumenau, SC -Tel.: (47) 3321 -0272-Fax: (47) 3321 -0233.
The levels of N‐acetyl galactosaminoglycan deacetylase in Neurospora crassa were determined at different stages of growth. The enzyme first appeared 24 h after inoculation. Deacetylase levels were increased by the presence of L‐sorbose, a sugar which induces colonial growth of N. crassa. The effect of L‐sorbose on deacetylase production, was also observed in the presence of other carbon sources. Ammonium tartrate also increased deacetylase activity, but without provoking morphological changes. Apparently, the effect of these two substances on deacetylase production by N. crassa was associated to the presence of galactosamine polymers in the culture medium, rather than to the morphological change itself.
A trehalase activity was purified from the mycelium of Chaetomium thermophilum var. corpophilum. The enzyme was composed of two identical polypeptides of apparent molecular mass of 98 kDa. The pI of the enzyme was about 3.9. The purified trehalase was stimulated by calcium, manganese and cobalt and inhibited by EDTA, ADP and ATP. The enzyme exhibited a Km of 0.63 mM, optimum pH of 6.5, and optimum temperature of 55°C. The C. thermophilum trehalase is another example of calcium‐dependent, thermophilic acid trehalases which exhibit mixed properties of regulated (neutral) and non‐regulated (acid) trehalases.
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