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Kinetic parameters and organic phosphorus remineralization potential of alkaline phosphatase activity in the tropical seagrass Thalassia testudinum and associated epiphyton
Title
Kinetic parameters and organic phosphorus remineralization potential of alkaline phosphatase activity in the tropical seagrass Thalassia testudinum and associated epiphyton.
Creator
Evans, Samantha Lorraine., Florida Atlantic University, Koch, Marguerite
Abstract/Description
Tropical carbonate estuaries are P-limited due to high carbonate sorption of DIP, therefore alternative P sources may represent an important contribution to the nutrient requirements of submerged aquatic vegetation. Alkaline phosphatase (AP'ase) is a cell-surface enzyme that allows aquatic plants to utilize the organic-P pool, and its activity (APA) may generate a significant portion of plant P-requirements in oligotrophic environments. Seasonal APA of the seagrass Thalassia testudinum and...
Show moreTropical carbonate estuaries are P-limited due to high carbonate sorption of DIP, therefore alternative P sources may represent an important contribution to the nutrient requirements of submerged aquatic vegetation. Alkaline phosphatase (AP'ase) is a cell-surface enzyme that allows aquatic plants to utilize the organic-P pool, and its activity (APA) may generate a significant portion of plant P-requirements in oligotrophic environments. Seasonal APA of the seagrass Thalassia testudinum and its epiphytic community was measured in NE Florida Bay. APA was higher for T. testudinum leaves with intact epiphytes (TTE) than for T. testudinum leaves alone (TT) in all seasons, and the spring growing season elicited the highest activities. Based on in situ PME levels (0.117--0.387muM), AP'ase P-remineralization rates were 0.326--2.181 for TTE and 0.237--0.823 for TT (mumol g-1 AFDW day-1), representing 26% and 4% of P-uptake, respectively. Therefore, APA may be an important P source to the seagrass-epiphyte consortium in tropical carbonate estuaries.
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Date Issued
2000
PURL
http://purl.flvc.org/fcla/dt/12714
Subject Headings
Alkaline phosphatase, Thalassia
Format
Document (PDF)
Alkaline phosphatase activity in symbiotic dinoflagellates (zooxanthellae) as a biological indicator of environmental phosphate exposure
Title
Alkaline phosphatase activity in symbiotic dinoflagellates (zooxanthellae) as a biological indicator of environmental phosphate exposure.
Creator
Annis, E. R., Cook, Clayton B.
Date Issued
2002
PURL
http://purl.flvc.org/FCLA/DT/3350894
Subject Headings
Dinoflagellates, Zooxanthella, Symbiosis, Alkaline phosphatase, Acid phosphatase, Montastraea
Format
Document (PDF)
Nutrient-enhanced growth of Cladophora prolifera in Harrington Sound, Bermuda: eutrophication of a confined, phosphorus-limited marine ecosystem
Title
Nutrient-enhanced growth of Cladophora prolifera in Harrington Sound, Bermuda: eutrophication of a confined, phosphorus-limited marine ecosystem.
Creator
Lapointe, Brian E., O'Connell, Julie D.
Date Issued
1989
PURL
http://purl.flvc.org/FCLA/DT/3173012
Subject Headings
Eutrophication, Nitrogen, Phosphorus, Productivity, Cladophora, Phosphatases
Format
Document (PDF)
Macroalgal production and nutrient relations in oligotrophic areas of Florida Bay
Title
Macroalgal production and nutrient relations in oligotrophic areas of Florida Bay.
Creator
Lapointe, Brian E.
Date Issued
1989
PURL
http://purl.flvc.org/FCLA/DT/3172781
Subject Headings
Water quality bioassay, Algae, Phosphatases, Nitrogen, Phosphorus
Format
Document (PDF)
Dysidiolide: a novel protein phosphatase inhibitor from the Caribbean sponge Dysidea etheria de Laubenfels
Title
Dysidiolide: a novel protein phosphatase inhibitor from the Caribbean sponge Dysidea etheria de Laubenfels.
Creator
Gunasekera, Sarath P., McCarthy, Peter J., Kelly-Borges, M., Lobkovsky, E., Clardy, J.
Date Issued
1996
PURL
http://purl.flvc.org/FCLA/DT/3319096
Subject Headings
Sponges --Research, Dysidiolide, Marine metabolites, Marine natural products, Protein phosphatases
Format
Document (PDF)
Microxine, a New cdc2 Kinase Inhibitor from the Australian MarinE Sponge Microxina Species
Title
Microxine, a New cdc2 Kinase Inhibitor from the Australian MarinE Sponge Microxina Species.
Creator
Killday, K. B., Yarwood, Donna, Sills, Matthew A., Murphy, Peter T., Hooper, J. N. A., Wright, Amy E.
Date Issued
2001
PURL
http://purl.flvc.org/FCLA/DT/3164092
Subject Headings
Sponges, Chromatographic analysis, Spectrum analysis, Phosphoprotein Phosphatase --analysis, Nucleosides
Format
Document (PDF)
Characterization of receptor protein tyrosine phosphatase PTP69D in the giant fiber circuit
Title
Characterization of receptor protein tyrosine phosphatase PTP69D in the giant fiber circuit.
Creator
Lee, LaTasha Hoskins, Godenschwege, Tanja A., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
PTP69D is a receptor protein tyrosine phosphatase (RPTP) with two intracellular catalytic domains (Cat1 and Cat2), which has been shown to play a role in axon outgrowth and guidance of embryonic motorneurons, as well as targeting of photoreceptor neurons in the visual system of Drosophila melanogaster. Here, we characterized the developmental role of PTP69D in the giant fiber (GF) neurons; two interneurons in the central nervous system (CNS) that control the escape response of the fly. In...
Show morePTP69D is a receptor protein tyrosine phosphatase (RPTP) with two intracellular catalytic domains (Cat1 and Cat2), which has been shown to play a role in axon outgrowth and guidance of embryonic motorneurons, as well as targeting of photoreceptor neurons in the visual system of Drosophila melanogaster. Here, we characterized the developmental role of PTP69D in the giant fiber (GF) neurons; two interneurons in the central nervous system (CNS) that control the escape response of the fly. In addition to guidance and targeting functions, our studies reveal an additional role for PTP69D in synaptic terminal growth in the CNS. We found that inhibition of phosphatase activity in catalytic domain (Cat1) proximal to the transmembrane domain did not affect axon guidance or targeting but resulted in stunted terminal growth of the GFs. Cell autonomous rescue and knockdown experiments demonstrated a function for PTP69D in the GFs, but not its postsynaptic target neurons. In addition,complementation studies and structure-function analyses revealed that for GF terminal growth, Cat1 function of PTP69D requires the immunoglobulin and the Cat2 domain but not the fibronectin type III repeats nor the membrane proximal region. In contrast, the fibronectin type III repeats, but not the immunoglobulin domains, were previously shown to be essential for axon targeting of photoreceptor neurons. Thus, our studies uncover a novel role for PTP69D in synaptic terminal growth in the CNS that is mechanistically distinct from its function during earlier developmental processes.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004301, http://purl.flvc.org/fau/fd/FA00004301
Subject Headings
Drosophila melanogaster., Protein-tyrosine phosphatase--Metabolism., Protein-tyrosine kinase., Protein kinases--Inhibitors., Phosphoprotein phosphatases., Transcription factors., Cell receptors., Cellular signal transduction.
Format
Document (PDF)
Secobatzellines A and B, two new enzyme inhibitors from a deep-water Caribbean sponge of the genus Batzella
Title
Secobatzellines A and B, two new enzyme inhibitors from a deep-water Caribbean sponge of the genus Batzella.
Creator
Gunasekera, Sarath P., McCarthy, Peter J., Longley, Ross E., Pomponi, Shirley A., Wright, Amy E.
Date Issued
1999
PURL
http://purl.flvc.org/FCLA/DT/3172682
Subject Headings
Sponges --Caribbean Sea, Marine natural products, Toxicity testing --In vitro, Phosphatases, Peptidase
Format
Document (PDF)
Purification and characterization of two members of the protein tyrosine phosphatase family
Title
Purification and characterization of two members of the protein tyrosine phosphatase family: dual specificity phosphatase PVP and low molecular weight phosphatase WZB.
Creator
Livingston, Paula A., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
Two protein tyrosine phosphatases, dual specificity phosphatase PVP and low molecular weight phosphatase WZB were purified and characterized. PVP was expressed as inclusion bodies and a suitable purification and refolding method was devised. Enzyme kinetics revealed that p-nitrophenylphosphate and (Sb(B-naphthyl phosphate were substrates with KM of 4.0mM and 8.1mM respectively. PVP showed no reactivity towards phosphoserine. Kinetic characterization of WZB showed that only...
Show moreTwo protein tyrosine phosphatases, dual specificity phosphatase PVP and low molecular weight phosphatase WZB were purified and characterized. PVP was expressed as inclusion bodies and a suitable purification and refolding method was devised. Enzyme kinetics revealed that p-nitrophenylphosphate and (Sb(B-naphthyl phosphate were substrates with KM of 4.0mM and 8.1mM respectively. PVP showed no reactivity towards phosphoserine. Kinetic characterization of WZB showed that only pnitrophenylphosphate was a substrate with no affinity for Ç-naphthyl phosphate and phosphoserine. Optimal conditions for activity with PNPP were found at a pH of 5 with a KM of 1.1mM, kcat of 35.4s-1 and kcat/KM of 32.2s-1mM-1. Inhibition studies showed that phosphate, fluoride, and molybdate were competitive inhibitors with Ki of 3.2mM, 71.7mM, and 50.4(So(BM respectively and hydrogen peroxide abolished activity. Active site mutants of WZB Cys9Ser and Asp115Asn showed no activity.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/332911
Subject Headings
Protein-tyrosine phosphatase, Cellular signal transduction, Cell cycle, Regulation, Membrane proteins, Structure-activity relationships, Protein kinases
Format
Document (PDF)