RESUMO
In laboratory culture, the toxic dinoflagellate Dinophysis acuminata acquires plastids from the ciliate, Mesodinium rubrum, which, in turn, acquires plastids from the cryptophyte, Teleaulax amphioxeia. Reports of D. acuminata from field samples found plastids of the raphidophyte, Heterosigma akashiwo within D. acuminata cells, suggesting a broader range of prey. Dinophysis blooms often co-occur with H. akashiwo in Delaware's inland bays. In the study presented here, predation on H. akashiwo by D. acuminata was investigated. Growth rates of D. acuminata were measured when cultured with H. akashiwo either alone or with its known prey, M. rubrum. M. rubrum was also cultured with H. akashiwo to examine predation by the ciliate as a vector for Heterosigma plastids. Ingestion rates by D. acuminata were measured when presented with H. akashiwo as prey, and retention of plastids from H. akashiwo was investigated by measuring chlorophyll a fluorescence intensities in D. acuminata cells presented with H. akashiwo as prey compared to M. rubrum. Additionally, a fluorescence-based method was developed to identify the presence of the accessory pigment fucoxanthin from H. akashiwo plastids in cells of D. acuminata. Results showed that the growth rate of D. acuminata was significantly lower when offered H. akashiwo as prey compared the growth rate when offered M. rubrum as prey. Likewise, no predation was observed when D. acuminata was offered H. akashiwo as prey. Intensity of chlorophyll a fluorescence was lower when H. akashiwo was offered as prey compared to M. rubrum, and fucoxanthin was not detected in any of the Dinophysis cells examined after incubation with H. akashiwo. Results of this investigation do not support the hypothesis that D. acuminata preys on H. akashiwo and highlight the need for further research on factors that stimulate the growth of Dinophysis in field populations.
Assuntos
Cilióforos , Dinoflagellida , Clorofila A , Cloroplastos , CriptófitasRESUMO
Expectant mothers and their spouses spend months preparing to eagerly welcome their much-anticipated baby into their family. Stillbirth or a diagnosis of life-limiting fetal anomalies comes as a devastating turn of events for affected women and their families. From the time of diagnosis to intervention (i.e., induction of labor for stillbirth or late termination of pregnancy for fetal anomalies), affected women often feel vulnerable and abandoned, with many experiencing long-term psychological and emotional effects. Knowledge of obstetric management, ethical and medical challenges, and psychological aspects have evolved in recent years. Familiarity with this emerging knowledge better prepares the obstetric anesthesiologist to deliver effective and empathic care. Encounters with women experiencing stillbirth and life-limiting fetal anomalies prompted this review of current evidence regarding parturient' perspectives on their care as they set out on the road to recovery.