Caren Helbing

Dr. Caren Helbing

orcid

Research Focus & Metrics

Academic Career Length

35Years (1992-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 September 2019 in Environmental DNA
Verified
Journal Article
Open access
PDF file
KKKaty Klymus
Katy Klymus
CMChristopher Merkes
Christopher Merkes
MAMichael J. Allison
Michael J. Allison
CGCaren S. Goldberg
Caren S. Goldberg
CHCaren Helbing
Caren Helbing
CRCatherine Richter
Catherine Richter
Background: Environmental DNA (eDNA) analysis is increasingly being used to detect the presence and relative abundance of rare species, especially invasive or imperiled aquatic species. The rapid progress in the eDNA field has resulted in numerous studies impacting conservation and management actions. However, standardization of eDNA methods and reporting across the field is yet to be fully established, with one area being the calculation and interpretation of assay limit of detection (LOD) and limit of quantification (LOQ).Aims: Here, we propose establishing consistent methods for determining and reporting of LOD and LOQ for single‐species quantitative PCR (qPCR) eDNA studies.Materials & Methods/ Results: We utilize datasets from multiple cooperating laboratories to demonstrate both a discrete threshold approach and a curve‐fitting modeling approach for determining LODs and LOQs for eDNA qPCR assays. We also provide details of an R script developed and applied for the modeling method.Discussion/Conclusions: Ultimately, standardization of how LOD and LOQ are determined, interpreted, and reported for eDNA assays will allow for more informed interpretation of assay results, more meaningful interlaboratory comparisons of experiments, and enhanced capacity for assessing the relative technical quality and performance of different eDNA qPCR assays.

1 August 2004 in Environmental Toxicology and Chemistry
Verified
Journal Article
Closed access
PDF file
CHChristina M. Howe
Christina M. Howe
MBMichael Berrill
Michael Berrill
BPBruce D. Pauli
Bruce D. Pauli
CHCaren Helbing
Caren Helbing
KWKate Werry
Kate Werry
NVNik Veldhoen
Nik Veldhoen
Gyphosate‐basedherbicides are among the most widely used pesticides in the world. We compared the acute toxicity of the glyphosate end‐use formulation Roundup Original® to four North American amphibian species (Rana clamitans, R. pipiens, R. sylvatica, and Bufo americanus) and the toxicity of glyphosate technical, the polyethoxylated tallowamine surfactant (POEA) commonly used in glyphosate‐based herbicides, and five newer glyphosate formulations to R. clamitans. For R. clamitans, acute toxicity values in order of decreasing toxicity were POEA > Roundup Original > Roundup Transorb® > Glyfos AU®; no significant acute toxicity was observed with glyphosate technical material or the glyphosate formulations Roundup Biactive®, Touchdown®, or Glyfos BIO®. Comparisons between the four amphibian species showed that the toxicity of Roundup Original varied with species and developmental stage. Rana pipiens tadpoles chronically exposed to environmentally relevant concentrations of POEA or glyphosate formulations containing POEA showed decreased snout‐vent length at metamorphosis and increased time to metamorphosis, tail damage, and gonadal abnormalities. These effects may be caused, in some part, by disruption of hormone signaling, because thyroid hormone receptor β mRNA transcript levels were elevated by exposure to formulations containing glyphosate and POEA. Taken together, the data suggest that surfactant composition must be considered in the evaluation of toxicity of glyphosate‐based herbicides.

1 December 2006 in Aquatic Toxicology
Verified
Journal Article
Closed access
NVNik Veldhoen
Nik Veldhoen
RSRachel C. Skirrow
Rachel C. Skirrow
HOHeather Osachoff
Heather Osachoff
HWHeidi Wigmore
Heidi Wigmore
DCDavid J. Clapson
David J. Clapson
CHCaren Helbing
Caren Helbing

18 November 2020 in Environmental DNA
Verified
Journal Article
Open access
PDF file
VLValerie S. Langlois
Valerie S. Langlois
MAMichael J. Allison
Michael J. Allison
LBLauren C. Bergman
Lauren C. Bergman
TTTuan Anh To
Tuan Anh To
CHCaren Helbing
Caren Helbing
Considerable promise and excitement exist in the application of environmental DNA (eDNA) methods to environmental monitoring and species inventories as eDNA can provide cost‐effective and accurate biodiversity information. However, considerable variation in data quality, rigor, and reliability has eroded confidence in eDNA application and is limiting regulatory and policy uptake. Substantial effort has gone into promoting transparency in reporting and deriving standardized frameworks and methods for eDNA field workflow components, but surprisingly little scrutiny has been given to the design and performance elements of targeted eDNA detection assays which, by far, have been most used in the scientific literature. There are several methods used for eDNA detection. The most accessible, cost‐effective, and conducive to standards development is targeted real‐time or quantitative real‐time polymerase chain reaction (abbreviated as qPCR) eDNA analysis. The present perspective is meant to assist in the development and evaluation of qPCR‐based eDNA assays. It evaluates six steps in the qPCR‐based eDNA assay development and validation workflow identifying and addressing concerns pertaining to poor qPCR assay design and implementation; identifies the need for more fulsome mitochondrial genome sequence information for a broader range of species; and brings solutions toward best practices in forthcoming large‐scale and worldwide eDNA applications, such as at‐risk or invasive species assessments and site remediation monitoring.

8 September 2004 in Molecular Biology and Evolution
Verified
Journal Article
Open access
PDF file
GHGordon H.Y. He
Gordon H.Y. He
CHCaren Helbing
Caren Helbing
MWMary J. Wagner
Mary J. Wagner
CSChristoph Sensen
Christoph Sensen
KRKarl Riabowol
Karl Riabowol
Since the discovery of ING1 class II tumor suppressors in 1996, five different ING genes (ING1 to ING5) encoding proteins with highly conserved plant homeodomain (PHD) motifs and several splicing isoforms of the ING1 and ING2 gene have been identified. The ING family functions in DNA repair and apoptosis in response to UV damage through binding to proliferating cell nuclear antigen (PCNA); chromatin remodeling and regulation of gene expression through regulating and/or targeting histone acetyltransferase/deacetylase (HAT/HDAC) activities; binding targets of rare phosphatidylinositol phosphates (PtdInsPs) that function in DNA damage-initiated stress signaling; and regulating brain tumor angiogenesis through transcriptional repression of NF-KB–responsive genes. To elucidate the evolutionary history of ING proteins and summarize what is known about regions highly conserved in the ING family members, we have examined the sequences and phylogenetic relationships of ING proteins across taxonomically diverse organisms. We have identified novel ING family members in rats, frogs, fish, mosquitoes, fruit flies, worms, fungi, and plants. We have also clarified the naming and classification of ING proteins based on our phylogenetic analysis to allow better understanding of the ING protein family. Using sequence similarities, we have identified novel regions and motifs of unknown function that are conserved across family members. An evolutionary history for the ING family of PHD finger proteins is presented that indicates that five ING genes are present in vertebrates. Three of these may be paralogs of ING genes found in arthropods, whereas nematodes, fungi, and green plants contain ING genes that have general features of the vertebrate ING family.

1 January 2010 in Environmental Health Perspectives
Verified
Journal Article
Open access
GAGraham Van Aggelen
Graham Van Aggelen
GAGerald T. Ankley
Gerald T. Ankley
WBWilliam S. Baldwin
William S. Baldwin
DBDaniel W. Bearden
Daniel W. Bearden
WBWilliam H. Benson
William H. Benson
LYLorraine Yu
Lorraine Yu
A peer-reviewed open access journal published by the National Institute of Environmental Health Sciences