Detection of urease in the cell wall and membranes from leaf tissues of bromeliad species


Autoria(s): CAMBUI, Camila Aguetoni; GASPAR, Marilia; MERCIER, Helenice
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

20/10/2012

20/10/2012

2009

Resumo

Urea is an important nitrogen source for some bromeliad species, and in nature it is derived from the excretion of amphibians, which visit or live inside the tank water. Its assimilation is dependent on the hydrolysis by urease (EC: 3.5.1.5), and although this enzyme has been extensively studied to date, little information is available about its cellular location. In higher plants, this enzyme is considered to be present in the cytoplasm. However, there is evidence that urease is secreted by the bromeliad Vriesea gigantea, implying that this enzyme is at least temporarily located in the plasmatic membrane and cell wall. In this article, urease activity was measured in different cell fractions using leaf tissues of two bromeliad species: the tank bromeliad V. gigantea and the terrestrial bromeliad Ananas comosus (L.) Merr. In both species, urease was present in the cell wall and membrane fractions, besides the cytoplasm. Moreover, a considerable difference was observed between the species: while V. gigantea had 40% of the urease activity detected in the membranes and cell wall fractions, less than 20% were found in the same fractions in A. comosus. The high proportion of urease found in cell wall and membranes in V. gigantea was also investigated by cytochemical detection and immunoreaction assay. Both approaches confirmed the enzymatic assay. We suggest this physiological characteristic allows tank bromeliads to survive in a nitrogen-limited environment, utilizing urea rapidly and efficiently and competing successfully for this nitrogen source against microorganisms that live in the tank water.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[06/5059-5]

Conselho Nacional de Desenvolvimento Cienti fico e Tecnologico (CNPq)[303715-04-9]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Identificador

PHYSIOLOGIA PLANTARUM, v.136, n.1, p.86-93, 2009

0031-9317

http://producao.usp.br/handle/BDPI/27309

10.1111/j.1399-3054.2009.01217.x

http://dx.doi.org/10.1111/j.1399-3054.2009.01217.x

Idioma(s)

eng

Publicador

WILEY-BLACKWELL PUBLISHING, INC

Relação

Physiologia Plantarum

Direitos

restrictedAccess

Copyright WILEY-BLACKWELL PUBLISHING, INC

Palavras-Chave #CANAVALIA-ENSIFORMIS #HELICOBACTER-PYLORI #MICROBIAL UREASES #NITROGEN #LOCALIZATION #PURIFICATION #SECRETION #AMMONIA #PROTEIN #GROWTH #Plant Sciences
Tipo

article

original article

publishedVersion