Reitzel A.M.,Woods Hole Oceanographic Institution |
Reitzel A.M.,University of North Carolina at Charlotte |
Passamaneck Y.J.,University of Hawaii at Manoa |
Karchner S.I.,Woods Hole Oceanographic Institution |
And 4 more authors.
Development Genes and Evolution | Year: 2014
The aryl hydrocarbon receptor (AHR) is a member of the basic helix-loop-helix/Per-ARNT-Sim (bHLH-PAS) family of transcription factors and has diverse roles in development, physiology, and environmental sensing in bilaterian animals. Studying the expression of conserved genes and function of proteins in outgroups to protostomes and deuterostomes assists in understanding the antiquity of gene function and deciphering lineage-specific differences in these bilaterian clades. We describe the developmental expression of AHR from the sea anemone Nematostella vectensis and compare its expression with three other members of the bHLH-PAS family (AHR nuclear translocator (ARNT), Cycle, and a proto-Single-Minded/Trachealess). NvAHR expression was highest early in the larval stage with spatial expression in the basal portion of the ectoderm that became increasingly restricted to the oral pole with concentrated expression in tentacles of the juvenile polyp. The other bHLH-PAS genes showed a divergent expression pattern in later larval stages and polyps, in which gene expression was concentrated in the aboral end, with broader expression in the endoderm later in development. In co-immunoprecipitation assays, we found no evidence for heterodimerization of AHR with ARNT, contrary to the conservation of this specific interaction in all bilaterians studied to date. Similar to results with other invertebrate AHRs but in contrast to vertebrate AHRs, NvAHR failed to bind two prototypical xenobiotic AHR ligands (2,3,7,8- tetrachlorodibenzo-p-dioxin, β-naphthoflavone). Together, our data suggest that AHR's original function in Eumetazoa likely involved developmental patterning, potentially of neural tissue. The role of heterodimerization in the function of AHR may have arisen after the cnidarian-bilaterian ancestor. The absence of xenobiotic binding to NvAHR further supports a hypothesis for a derived role of this protein in chemical sensing within the chordates. © 2013 Springer-Verlag Berlin Heidelberg.
Battelle B.-A.,Whitney Laboratory for Marine Bioscience |
Battelle B.-A.,University of Florida |
Kempler K.E.,Whitney Laboratory for Marine Bioscience |
Kempler K.E.,University of Florida |
And 5 more authors.
Journal of Experimental Biology | Year: 2013
Dark and light adaptation in photoreceptors involve multiple processes including those that change protein concentrations at photosensitive membranes. Light- and dark-adaptive changes in protein levels at rhabdoms have been described in detail in white-eyed Drosophila maintained under artificial light. Here we tested whether protein levels at rhabdoms change significantly in the highly pigmented lateral eyes of wild-caught Limulus polyphemus maintained in natural diurnal illumination and whether these changes are under circadian control. We found that rhabdomeral levels of opsins (Ops1-2), the G protein activated by rhodopsin (Gqα) and arrestin change significantly from day to night and that nighttime levels of each protein at rhabdoms are significantly influenced by signals from the animal's central circadian clock. Clock input at night increases Ops1-2 and Gqα and decreases arrestin levels at rhabdoms. Clock input is also required for a rapid decrease in rhabdomeral Ops1-2 beginning at sunrise. We found further that dark adaptation during the day and the night are not equivalent. During daytime dark adaptation, when clock input is silent, the increase of Ops1-2 at rhabdoms is small and Gqα levels do not increase. However, increases in Ops1-2 and Gqα at rhabdoms are enhanced during daytime dark adaptation by treatments that elevate cAMP in photoreceptors, suggesting that the clock influences dark-adaptive increases in Ops1-2 and Gqα at Limulus rhabdoms by activating cAMP-dependent processes. The circadian regulation of Ops1-2 and Gqα levels at rhabdoms probably has a dual role: to increase retinal sensitivity at night and to protect photoreceptors from light damage during the day. © 2013. Published by The Company of Biologists Ltd.
Gabriel M.C.,National Exposure Research Laboratory NERL |
Howard N.,University of Florida |
Osborne T.Z.,University of Florida |
Osborne T.Z.,Whitney Laboratory for Marine Bioscience
Environmental Management | Year: 2014
Few published studies present data on relationships between fish mercury and surface or pore water sulfate concentrations, particularly on an ecosystem-wide basis. Resource managers can use these relationships to identify the sulfate conditions that contain fish with health-concerning total mercury (THg) levels and to evaluate the role of sulfate in methyl-mercury (MeHg) production. In this study, we derived relationships between THg in three fish trophic levels (mosquitofish, sunfish, and age-1 large-mouth bass) and surface water sulfate from 1998 to 2009 for multiple stations across the Everglades Protection Area (EPA). Results show the relationship between sulfate and fish THg in each fish type is nonlinear and largely skewed, similar to the relationship between MeHg production and sulfate concentration in peatland sediment pore water identified by other researchers. Peak fish THg levels occurred in ∼ 1 to 12 mg/L sulfate conditions. There was significant variability in the fish THg data, and there were several instances of high-fish THg levels in high-sulfate conditions (>30 mg/L). Health-concerning fish THg levels were present in all surface water sulfate conditions; however, most of these levels occurred in 1-20 mg/L sulfate. The data in this study, including recent studies, show consistent and identifiable areas of high- and low-fish THg across the spectrum of surface water sulfate concentration, therefore, applying an ecosystem-wide sulfur strategy may be an effective management approach as it would significantly reduce MeHg risk in the EPA. © The Author(s) 2014.
Sucar S.,Valdosta State University |
Sucar S.,Instituto Nacional de Tecnologia Agropecuaria |
Moore G.L.,Valdosta State University |
Moore G.L.,University of Florida |
And 3 more authors.
G3: Genes, Genomes, Genetics | Year: 2016
The mangrove killifish, Kryptolebias marmoratus, is unique among vertebrates due to its self-fertilizing mode of reproduction involving an ovotestis. As a result, it constitutes a simplistic and desirable vertebrate model for developmental genetics as it is easily maintained, reaches sexual maturity in about 100 days, and provides a manageable number of relatively clear embryos. After the establishment and characterization of an initial mutagenesis pilot screen using N-ethyl-N-nitrosourea, a three-generation genetic screen was performed to confirm zygotic mutant allele heritability and simultaneously score for homozygous recessive mutant sterile F2 fish. From a total of 307 F2 fish screened, 10 were found to be 1° males, 16 were sterile, 92 wild-type, and the remaining 189, carriers of zygotic recessive alleles. These carriers produced 25% progeny exhibiting several zygotic phenotypes similar to those previously described in zebrafish and in the aforementioned pilot screen, as expected. Interestingly, new phenotypes such as golden yolk, no trunk, and short tail were observed. The siblings of sterile F2 mutants were used to produce an F3 generation in order to confirm familial sterility. Out of the 284 F3 fish belonging to 10 previously identified sterile families, 12 were found to be 1° males, 69 were wild-type, 83 sterile, and 120 were classified as */+ (either wild-type or carriers) with undefined genotypes. This screen provides proof of principle that K. marmoratus is a powerful vertebrate model for developmental genetics and can be used to identify mutations affecting fertility. © 2016 Sucar et al.
Liao J.C.,Whitney Laboratory for Marine Bioscience
Biology Letters | Year: 2010
The lateral line system of larval zebrafish can translate hydrodynamic signals from the environment to guide body movements. Here, I demonstrate a spatial relationship between the organization of afferent neurons in the lateral line ganglion and the innervation of neuromasts along the body. I developed a whole cell patch clamp recording technique to show that afferents innervate multiple direction-sensitive neuromasts, which are sensitive to low fluid velocities. This work lays the foundation to integrate sensory neuroscience and the hydrodynamics of locomotion in a model genetic system. © 2010 The Royal Society.
Yamaguchi E.,University of Hawaii at Manoa |
Seaver E.C.,University of Hawaii at Manoa |
Seaver E.C.,Whitney Laboratory for Marine Bioscience
Invertebrate Biology | Year: 2013
In many marine invertebrates with biphasic life cycles, juvenile/adult traits begin to develop before metamorphosis. For structures that are present at multiple developmental stages, but have distinct larval and adult forms, it is unclear whether larval and adult structures have shared or distinct developmental origins. In this study, we examine the relationship between the larval and adult eyes in the polychaete Capitella teleta. In addition, we describe a novel marker for larval and juvenile photoreceptor cells. Infrared laser deletion of individual micromeres in early embryos suggests that the same micromeres at the eight-cell stage that are specified to generate the larval eyes also form the adult eyes. Direct deletion of the larval eye, including the pigment cell and the corresponding photoreceptor cell, resulted in a lack of shading pigment cells in juveniles and adults, demonstrating that this structure does not regenerate. However, a sensory photoreceptor cell was present in juveniles following direct larval eye deletions, indicating that larval and adult photoreceptors are separate cells. We propose that the formation of the adult eye in juveniles of C. teleta requires the presence of the pigment cell of the larval eye, but the adult photoreceptor is either recruited from adjacent neural tissue or arises de novo after metamorphosis. These results are different from the development and spatial orientation of larval and adult eyes found in other polychaetes, in which two scenarios have been proposed: larval eyes persist and function as adult eyes; or, distinct pigmented adult eyes begin developing separately from larval eyes prior to metamorphosis. © 2013, The American Microscopical Society, Inc.