DSpace Collection:
http://www.dspace.espol.edu.ec/handle/123456789/5862
2024-03-04T16:40:21ZCresolase, catecholase and laccase activities in haemocytes of the red swamp crayfish
http://www.dspace.espol.edu.ec/handle/123456789/5875
Title: Cresolase, catecholase and laccase activities in haemocytes of the red swamp crayfish
Authors: Cardenas Medranda, Washington Bolívar; Dankert, John R.
Abstract: Phenoloxidase activity in crayfish haemocyte lysates and extracts of haemocyte
membranes were studied using native PAGE and SDS-PAGE gels and
staining for cresolase, catecholase and laccase activities. The activation of the
proenzyme, prophenoloxidase to phenoloxidase, in native PAGE was demonstrated
following exposure to SDS. By staining samples separated in SDSPAGE
followed by renaturation, a high molecular mass phenoloxidase
activity was identified in both the soluble and membrane fractions of haemocyte
preparations. The membrane-associated activity appeared at only relatively
high molecular mass (>300 kDa), and could easily be eluted from
membranes using detergents or NaCl. Further, this membrane-associated
activity has a catecholase activity but not the cresolase activity seen in the
soluble preparations. In addition, several other phenoloxidase enzymes were
identified with di#erent relative mobilities (250, 80, 72 and 10 kDa). Crayfish
haemocytes also contained laccase activity, thought to be restricted to cuticle
sclerotisation in the integument. Laccase activity in haemocytes might aid in
the formation of capsule used to contain pathogens.1999-05-31T00:00:00ZFotos laboratorío biomedicina
http://www.dspace.espol.edu.ec/handle/123456789/5879
Title: Fotos laboratorío biomedicina
Authors: Cardenas Medranda, Washington Bolívar
Abstract: FOTOS LABORATORIO BIOMEDICINA
Description: FOTOS LABORATORIO BIOMEDICINA2009-07-08T00:00:00ZFlow cytometric analysis of crayfish haemocytes activated by lipopolysaccharides
http://www.dspace.espol.edu.ec/handle/123456789/5876
Title: Flow cytometric analysis of crayfish haemocytes activated by lipopolysaccharides
Authors: Cardenas Medranda, Washington Bolívar; Dankert, John R.; Jenkins, Jill A.
Abstract: Lipopolysaccharides (LPS) from Gram-negative bacteria are strong stimulators of white river crayfish, Procambarus
zonangulus, haemocytes in vitro. Following haemocyte treatment with LPS and with LPS from rough mutant R5 (LPS
Rc) from Salmonella minnesota, flow cytometric analysis revealed a conspicuous and reproducible decrease in cell size as
compared to control haemocytes. These LPS molecules also caused a reduction in haemocyte viability as assessed by
flow cytometry with the fluorescent dyes calcein-AM and ethidium homodimer. The onset of cell size reduction was
gradual and occurred prior to cell death. Haemocytes treated with LPS from S. minnesota without the Lipid A moiety
(detoxified LPS) decreased in size without a reduction of viability. The action of LPS on crayfish haemocytes appeared
to be related to the activation of the prophenoloxidase system because phenoloxidase (PO)-specific activity in the
supernatants from control and detoxified LPS-treated cells was significantly lower than that from LPS and LPS-Rc
treated cells (P%0:05). Furthermore, addition of trypsin inhibitor to the LPS treatments caused noticeable delays in
cell size and viability changes. These patterns of cellular activation by LPS formulations indicated that crayfish
haemocytes react differently to the polysaccharide and lipid A moieties of LPS, where lipid A is cytotoxic and the
polysaccharide portion is stimulatory. These effects concur with the general pattern of mammalian cell activation by
LPS, thereby indicating common innate immune recognition mechanisms to bacterial antigens between cells from
mammals and invertebrates. These definitive molecular approaches used to verify and identify mechanisms of
invertebrate haemocyte responses to LPS could be applied with other glycoconjugates, soluble mediators, or xenobiotic
compounds.2004-01-01T00:00:00ZCurriculo vitae
http://www.dspace.espol.edu.ec/handle/123456789/5877
Title: Curriculo vitae
Authors: Cardenas Medranda, Washington Bolívar2009-01-01T00:00:00Z