Zoospore Fine Structure of the Parasite Olpidiopsis saprolegniae Variety saprolegniae (Oomycetes, Lagenidiales)

Bortnick, Richard N.; Powell, Martha J.; Bangert, Thomas N.

doi:10.2307/3793298

Cited by 21 publications

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“…; Bortnick et al. ; Powell and Blackwell ; Powell et al. ; Randolph and Powell ; Sadowski and Powell ) remains an intriguing avenue to explore in understanding how oomycetes colonize substrates and how to design targeted strategies preventing adhesion of parasitic oomycetes to hosts (Beakes ).…”

Section: Discussionmentioning

confidence: 99%

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Cytochemical Localization of Polyphenol Oxidase Activity in K2‐Bodies of Saprolegnia ferax Secondary Zoospores

Lehnen

Powell

Letcher

2018

J Eukaryotic Microbiology

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Zoospores of the oomycete Saprolegnia ferax release adhesive material from K-bodies at the onset of attachment to substrates. To understand more fully how K-bodies function in adhesion, enzyme activity was investigated cytochemically in secondary zoospores. Presence of catalase, a marker enzyme for microbodies, was explored in the diaminobenzidine (DAB) reaction. Although pH 9.2 DAB-staining characteristic of catalase activity was detected in the granular matrix regions of K-bodies, reaction controls indicated that the reaction was due to oxidative enzyme activity other than catalase. Because polyphenol oxidase (PPO) is another metal-containing enzyme capable of oxidizing DAB, activity of this enzyme was tested with a more specific substrate, dihydroxyphenylalanine (DOPA). In the DOPA procedure, reaction product was exclusively localized within K-bodies, indicating the presence of PPO. Results with three methods of reaction controls (elimination of substrate, addition of a PPO enzyme inhibitor, and heat-inactivation of enzymes) all supported the presence of PPO in K-bodies. This study highlights potential roles for K-body PPO in stabilization of adhesion bodies by: cross-linking matrix phenolic proteins or glycoproteins as K-bodies discharge adhesives onto substrates, or polymerizing phenolics protective against microbial attacks of the adhesion pad.

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Section: Discussionmentioning

confidence: 99%

“…Cultures of S. ferax were maintained on CM+ agar (Bortnick et al. ; Lehnen and Powell ). Secondary zoospores were generated from primary cysts as described in Lehnen and Powell (, ).…”

Section: Methodsmentioning

confidence: 99%