ORCID Profile
0000-0003-0754-5751
Current Organisations
American Museum of Natural History
,
University of Maryland at College Park
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Publisher: Oxford University Press (OUP)
Date: 17-05-2021
Abstract: The performance of DNA metabarcoding approaches for characterizing bio ersity can be influenced by multiple factors. Here, we used morphological assessment of taxa in zooplankton s les to develop a large barcode database and to assess the congruence of taxonomic identification with metabarcoding under different conditions. We analysed taxonomic assignment of metabarcoded s les using two genetic markers (COI, 18S V1–2), two types of clustering into molecular operational taxonomic units (OTUs, ZOTUs), and three methods for taxonomic assignment (RDP Classifier, BLASTn to GenBank, BLASTn to a local barcode database). The local database includes 1042 COI and 1108 18S (SSU) barcode sequences, and we added new high-quality sequences to GenBank for both markers, including 109 contributions at the species level. The number of phyla detected and the number of taxa identified to phylum varied between a genetic marker and among the three methods used for taxonomic assignments. Blasting the metabarcodes to the local database generated multiple unique contributions to identify OTUs and ZOTUs. We argue that a multi-marker approach combined with taxonomic expertise to develop a curated, vouchered, local barcode database increases taxon detection with metabarcoding, and its potential as a tool for zooplankton bio ersity surveys.
Publisher: Springer Science and Business Media LLC
Date: 18-04-2022
DOI: 10.1186/S12983-022-00460-1
Abstract: Intracellular sequestration requires specialized cellular and molecular mechanisms allowing a predator to retain and use specific organelles that once belonged to its prey. Little is known about how common cellular mechanisms, like phagocytosis, can be modified to selectively internalize and store foreign structures. One form of defensive sequestration involves animals that sequester stinging organelles (nematocysts) from their cnidarian prey. While it has been hypothesized that nematocysts are identified by specialized phagocytic cells for internalization and storage, little is known about the cellular and developmental mechanisms of this process in any metazoan lineage. This knowledge gap is mainly due to a lack of genetically tractable model systems among predators and their cnidarian prey. Here, we introduce the nudibranch Berghia stephanieae as a model system to investigate the cell, developmental, and physiological features of nematocyst sequestration selectivity. We first show that B. stephanieae , which feeds on Exaiptasia diaphana , selectively sequesters nematocysts over other E. diaphana tissues found in their digestive gland. Using confocal microscopy, we document that nematocyst sequestration begins shortly after feeding and prior to the formation of the appendages (cerata) where the organ responsible for sequestration (the cnidosac) resides in adults. This finding is inconsistent with previous studies that place the formation of the cnidosac after cerata emerge. Our results also show, via live imaging assays, that both nematocysts and dinoflagellates can enter the nascent cnidosac structure. This result indicates that selectivity for nematocysts occurs inside the cnidosac in B. stephanieae , likely in the cnidophage cells themselves. Our work highlights the utility of B. stephanieae for future research, because: (1) this species can be cultured in the laboratory, which provides access to all developmental stages, and (2) the transparency of early juveniles makes imaging techniques (and therefore cell and molecular assays) feasible. Our results pave the way for future studies using live imaging and targeted gene editing to identify the molecular mechanisms involved in nematocyst sequestration. Further studies of nematocyst sequestration in B. stephanieae will also allow us to investigate how common cellular mechanisms like phagocytosis can be modified to selectively internalize and store foreign structures.
Location: United States of America
Location: United States of America
Location: United States of America
Location: United States of America
Location: United States of America
No related grants have been discovered for Jessica Goodheart.