TY - JOUR
T1 - Infochemicals released by Daphnia magna fed on Microcystis aeruginosa affect mcyA gene expression
AU - Pineda-Mendoza, Rosa María
AU - Zúñiga, Gerardo
AU - Martínez-Jerónimo, Fernando
N1 - Funding Information:
We thank Dr. María Cabañas and Dr. Guillermo Elizondo (CINVESTAV-IPN) for their assistance in the RT-qPCR. This work was part of Pineda-Mendoza’s PhD dissertation. Pineda-Mendoza has a scholarship of the Consejo Nacional de Ciencia y Tecnología (No. 206867 ) and had also support from the Programa Institucional de Formación de Investigadores-Instituto Politécnico Nacional (PIFI-IPN) . F. Martínez-Jerónimo and G. Zúñiga are thankful for financial support provided by the Sistema de Estímulo al Desempeño de los Investigadores (EDI) and the Comisión de Operación y Fomento de Actividades Académicas (COFAA) of the Instituto Politécnico Nacional. We acknowledge the editorial assistance of Ms. Ingrid Mascher. Finally, thanks to the two anonymous reviewers whose critical comments helped to improve this contribution.
PY - 2014/3/15
Y1 - 2014/3/15
N2 - Microcystins (MCs) are toxic heptapeptides produced by cyanobacteria during blooms that are noxious to diverse organisms, from bacteria to vertebrates. Specifically in daphnids, they cause reduced growth, a low reproductive rate, and, in extreme cases, death; however, different infochemicals released by cladocerans stimulate MCs synthesis. Ecological cyanobacteria-daphnids interactions are complex and not clear yet. In this study, we evaluated the effects of infochemicals released by Daphnia magna neonates and adults fed with different concentrations of Microcystis aeruginosa on population growth of strains Ch10 and UTEX LB2385 of M. aeruginosa, mcyA gene expression in real time qPCR, and the intracellular concentration of MCs. In addition, we assessed the relation between the cellular diameter and the intracellular concentration of MCs in both strains. Chlorophyll content per cell was affected by the presence of infochemicals from D. magna neonates and adults. mcyA gene was significantly overexpressed in the early stages of population growth (5 days) in all treatments with strain UTEX LB2385, whereas overexpression was observed in strain Ch10 at the end stage of the exponential and stationary phases (10 and 15 days). Intracellular concentration of MCs varied with the tested factor. Results suggest that the increase in mcyA gene expression and in MCs production could be defense mechanisms against the consumption by D. magna. Results also demonstrate the physiological plasticity among Microcystis strains, which could explain the permanence and dominance of this genus in toxic blooms.
AB - Microcystins (MCs) are toxic heptapeptides produced by cyanobacteria during blooms that are noxious to diverse organisms, from bacteria to vertebrates. Specifically in daphnids, they cause reduced growth, a low reproductive rate, and, in extreme cases, death; however, different infochemicals released by cladocerans stimulate MCs synthesis. Ecological cyanobacteria-daphnids interactions are complex and not clear yet. In this study, we evaluated the effects of infochemicals released by Daphnia magna neonates and adults fed with different concentrations of Microcystis aeruginosa on population growth of strains Ch10 and UTEX LB2385 of M. aeruginosa, mcyA gene expression in real time qPCR, and the intracellular concentration of MCs. In addition, we assessed the relation between the cellular diameter and the intracellular concentration of MCs in both strains. Chlorophyll content per cell was affected by the presence of infochemicals from D. magna neonates and adults. mcyA gene was significantly overexpressed in the early stages of population growth (5 days) in all treatments with strain UTEX LB2385, whereas overexpression was observed in strain Ch10 at the end stage of the exponential and stationary phases (10 and 15 days). Intracellular concentration of MCs varied with the tested factor. Results suggest that the increase in mcyA gene expression and in MCs production could be defense mechanisms against the consumption by D. magna. Results also demonstrate the physiological plasticity among Microcystis strains, which could explain the permanence and dominance of this genus in toxic blooms.
KW - Bloom
KW - Cladocera
KW - Cyanobacteria
KW - Gene expression
KW - Microcystins
KW - qPCR
UR - http://www.scopus.com/inward/record.url?scp=84893820546&partnerID=8YFLogxK
U2 - 10.1016/j.toxicon.2014.01.008
DO - 10.1016/j.toxicon.2014.01.008
M3 - Artículo
C2 - 24467996
SN - 0041-0101
VL - 80
SP - 78
EP - 86
JO - Toxicon
JF - Toxicon
ER -