scholarly journals A scalable culturing system for the marine annelid Platynereis dumerilii

2019 ◽  
Author(s):  
Emily Kuehn ◽  
Alexander W. Stockinger ◽  
Jerome Girard ◽  
Florian Raible ◽  
B. Duygu Özpolat
Keyword(s):  
Aquatic Organisms ◽  
Model System ◽  
Light Conditions ◽  
Cell Type ◽  
Culture Methods ◽  
Cell Lineages ◽  
Full Life Cycle ◽  
Platynereis Dumerilii ◽  
Culturing Conditions ◽  
And Behavior

ABSTRACTPlatynereis dumerilii is a marine segmented worm (annelid) with externally fertilized embryos and it can be cultured for the full life cycle in the laboratory. The accessibility of embryos and larvae combined with the breadth of the established molecular and functional techniques has made P. dumerilii an attractive model for studying development, cell lineages, cell type evolution, reproduction, regeneration, the nervous system, and behavior. Traditionally, these worms have been kept in rooms dedicated for their culture. This allows for the regulation of temperature and light cycles, which is critical to synchronizing sexual maturation. However, regulating the conditions of a whole room present limitations, especially if experiments require being able to change culturing conditions. Here we present scalable and flexible culture methods that provide ability to control the environmental conditions, and have a multi-purpose culture space. We provide a closed setup shelving design with proper light conditions necessary for P. dumerilii to mature. We also implemented a standardized method of feeding P. dumerilii cultures with powdered spirulina which relieves the ambiguity associated with using frozen spinach, and helps standardize nutrition conditions across experiments and across different labs. By using these methods, we were able to raise mature P. dumerilii, capable of spawning and producing viable embryos for experimentation and replenishing culture populations. These methods will allow for the further accessibility of P. dumerilii as a model system, and they can be adapted for other aquatic organisms.

Altered TNF-α, glucose, insulin, and amino acids in islets of Langerhans cultured in a microgravity model system

2001 ◽  
Vol 280 (1) ◽  
pp. E92-E102 ◽  
Author(s):  
Brian W. Tobin ◽  
Sandra K. Leeper-Woodford ◽  
Brian B. Hashemi ◽  
Scott M. Smith ◽  
Clarence F. Sams
Keyword(s):  
Cell Culture ◽  
Pancreatic Islets ◽  
Islets Of Langerhans ◽  
Three Dimensional ◽  
Model System ◽  
Culture Methods ◽  
Static Culture ◽  
Pancreatic Islets Of Langerhans ◽  
Tnf Α ◽  
Factor Α

The present studies were designed to determine effects of a microgravity model system upon lipopolysaccharide (LPS)-stimulated tumor necrosis factor-α (TNF-α) activity and indexes of insulin and fuel homeostasis of pancreatic islets of Langerhans. Islets (1,726 ± 117, 150 islet equivalent units) from Wistar-Furth rats were treated as 1) high aspect ratio vessel (HARV) cell culture, 2) HARV plus LPS, 3) static culture, and 4) static culture plus LPS. TNF-α (L929 cytotoxicity assay) was significantly increased in LPS-induced HARV and static cultures; yet the increase was more pronounced in the static culture group ( P < 0.05). A decrease in insulin concentration was demonstrated in the LPS-stimulated HARV culture ( P< 0.05). We observed a greater glucose concentration and increased disappearance of arginine in islets cultured in HARVs. Although nitrogenous compound analysis indicated a ubiquitous reliance on glutamine in all experimental groups, arginine was converted to ornithine at a twofold greater rate in the islets cultured in the HARV microgravity model system ( P < 0.05). These studies demonstrate alterations in LPS-induced TNF-α production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV. These alterations in fuel homeostasis may be promulgated by gravity-averaged cell culture methods or by three-dimensional cell assembly.

scholarly journals Inelastic hyperspectral lidar for aquatic ecosystems monitoring and landscape plant scanning test

2018 ◽  
Vol 176 ◽  
pp. 01003
Author(s):  
Guangyu Zhao ◽  
Elin Malmqvist ◽  
Klas Rydhmer ◽  
Alfred Strand ◽  
Giuseppe Bianco ◽  
...  
Keyword(s):  
Diode Laser ◽  
Temporal Resolution ◽  
Aquatic Ecosystems ◽  
Focal Depth ◽  
Aquatic Organisms ◽  
Landscape Plant ◽  
Optical Arrangement ◽  
Spatio Temporal ◽  
And Behavior

We have developed an aquatic inelastic hyperspectral lidar with unrestricted focal-depth and enough sensitivity and spatio-temporal resolution to detect and resolve position and behavior of individual sub-millimeter aquatic organisms. We demonstrate ranging with monitoring of elastic echoes, water Raman signals and fluorescence from chlorophyllbearing phytoplankton and dye tagged organisms. The system is based on a blue CW diode laser and a Scheimpflug optical arrangement.

Heat shock induces mini-Cajal bodies in the Xenopus germinal vesicle

2002 ◽  
Vol 115 (10) ◽  
pp. 2011-2020 ◽  
Author(s):  
Korie E. Handwerger ◽  
Zheng'an Wu ◽  
Christine Murphy ◽  
Joseph G. Gall
Keyword(s):  
Heat Shock ◽  
Germinal Vesicle ◽  
Model System ◽  
Cajal Body ◽  
Self Organization ◽  
Cajal Bodies ◽  
Oocyte Nucleus ◽  
Evolutionarily Conserved ◽  
And Behavior ◽  
Heat Shock Induction

Cajal bodies are evolutionarily conserved nuclear organelles that are believed to play a central role in assembly of RNA transcription and processing complexes. Although knowledge of Cajal body composition and behavior has greatly expanded in recent years, little is known about the molecules and mechanisms that lead to the formation of these organelles in the nucleus. The Xenopus oocyte nucleus or germinal vesicle is an excellent model system for the study of Cajal bodies, because it is easy to manipulate and it contains 50-100 Cajal bodies with diameters up to 10 μm. In this study we show that numerous mini-Cajal bodies (less than 2 μm in diameter) form in the germinal vesicle after oocytes recover from heat shock. The mechanism for heat shock induction of mini-Cajal bodies is independent of U7 snRNA and does not require transcription or import of newly translated proteins from the cytoplasm. We suggest that Cajal bodies originate by self-organization of preformed components, preferentially on the surface of B-snurposomes.

scholarly journals Lake Phytoplankton Assemblage Altered by Irregularly Shaped PLA Body Wash Microplastics but Not by PS Calibration Beads

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2650
Author(s):  
Kiyoko Yokota ◽  
Marissa Mehlrose
Keyword(s):  
Aquatic Organisms ◽  
Environmental Pollutant ◽  
Taxonomic Composition ◽  
Consumer Products ◽  
Source Water ◽  
Phytoplankton Assemblage ◽  
Phytoplankton Communities ◽  
Aquatic Food ◽  
And Behavior ◽  
Natural Phytoplankton

Microplastics are an emerging environmental pollutant, whose global ubiquity is becoming increasingly evident. Conventional wastewater treatment does not completely remove them, and there are growing concerns about microplastics in source water and post-treatment drinking water. Microplastics have been reported to alter the development, physiology, and behavior of various aquatic organisms; however, limited knowledge exists on their effect on natural phytoplankton communities. Many studies also use uniformly spherical plastic beads, while most scrub particles in consumer products and secondary microplastics in the environment have various shapes and sizes. We tested the effects of two types of microplastics, 50 µm polystyrene (PS) calibration beads and polylactic acid (PLA) plastic body wash scrub particles, and one type of plant-derived body wash scrub particle on a natural phytoplankton assemblage through a 7-day incubation experiment in a temperate, mesotrophic lake. The calibration beads and the plant-derived particles generally did not alter the taxonomic composition of the phytoplankton in the mesocosms, while the PLA body wash microplastics eliminated cryptophytes (p < 0.001) and increased chrysophytes (p = 0.041). Our findings demonstrate differential effects of irregularly shaped PLA body wash microplastics vs. PS calibration beads on lake phytoplankters and empirically support potential bottom-up alteration of the aquatic food web by secondary microplastics.

scholarly journals Hormone-Activated Estrogen Receptors in Annelid Invertebrates: Implications for Evolution and Endocrine Disruption

Endocrinology ◽  
2008 ◽  
Vol 150 (4) ◽  
pp. 1731-1738 ◽  
Author(s):  
June Keay ◽  
Joseph W. Thornton
Keyword(s):  
Estrogen Receptors ◽  
Endocrine Disruption ◽  
Endocrine Disrupting Chemicals ◽  
Estrogen Signaling ◽  
Estrogen Sensitivity ◽  
Endocrine Disrupting ◽  
Platynereis Dumerilii ◽  
Bilaterian Animal ◽  
Capitella Capitata ◽  
And Behavior

As the primary mediators of estrogen signaling in vertebrates, estrogen receptors (ERs) play crucial roles in reproduction, development, and behavior. They are also the major mediators of endocrine disruption by xenobiotic pollutants that mimic or block estrogen action. ERs that are sensitive to estrogen and endocrine disrupters have long been thought to be restricted to vertebrates: although there is evidence for estrogen signaling in invertebrates, the only ERs studied to date, from mollusks and cephalochordates, have been insensitive to estrogen and therefore incapable of mediating estrogen signaling or disruption. To determine whether estrogen sensitivity is ancestral or a unique characteristic of vertebrate ERs, we isolated and characterized ERs from two annelids, Platynereis dumerilii and Capitella capitata, because annelids are the sister phylum to mollusks and have been shown to produce and respond to estrogens. Functional assays show that annelid ERs specifically activate transcription in response to low estrogen concentrations and bind estrogen with high affinity. Furthermore, numerous known endocrine-disrupting chemicals activate or antagonize the annelid ER. This is the first report of a hormone-activated invertebrate ER. Our results indicate that estrogen signaling via the ER is as ancient as the ancestral bilaterian animal and corroborate the estrogen sensitivity of the ancestral steroid receptor. They suggest that the taxonomic scope of endocrine disruption by xenoestrogens may be very broad and reveal how functional diversity evolved in a gene family central to animal endocrinology.

scholarly journals Dynamics of gene expression in single root cells ofA. thaliana

2018 ◽  
Author(s):  
Ken Jean-Baptiste ◽  
José L. McFaline-Figueroa ◽  
Cristina M. Alexandre ◽  
Michael W. Dorrity ◽  
Lauren Saunders ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Developmental Trajectories ◽  
Cell Types ◽  
Cell Type ◽  
Specific Expression ◽  
Root Cells ◽  
Cell Lineages ◽  
Cell Type Specific Expression ◽  
Cell Type Specific

ABSTRACTSingle-cell RNA-seq can yield high-resolution cell-type-specific expression signatures that reveal new cell types and the developmental trajectories of cell lineages. Here, we apply this approach toA. thalianaroot cells to capture gene expression in 3,121 root cells. We analyze these data with Monocle 3, which orders single cell transcriptomes in an unsupervised manner and uses machine learning to reconstruct single-cell developmental trajectories along pseudotime. We identify hundreds of genes with cell-type-specific expression, with pseudotime analysis of several cell lineages revealing both known and novel genes that are expressed along a developmental trajectory. We identify transcription factor motifs that are enriched in early and late cells, together with the corresponding candidate transcription factors that likely drive the observed expression patterns. We assess and interpret changes in total RNA expression along developmental trajectories and show that trajectory branch points mark developmental decisions. Finally, by applying heat stress to whole seedlings, we address the longstanding question of possible heterogeneity among cell types in the response to an abiotic stress. Although the response of canonical heat shock genes dominates expression across cell types, subtle but significant differences in other genes can be detected among cell types. Taken together, our results demonstrate that single-cell transcriptomics holds promise for studying plant development and plant physiology with unprecedented resolution.

scholarly journals Arp2/3 complex-mediated actin assembly drives microtubule-independent motility and phagocytosis in the evolutionarily divergent amoeba Naegleria

2020 ◽  
Author(s):  
Katrina B. Velle ◽  
Lillian K. Fritz-Laylin
Keyword(s):  
Actin Cytoskeleton ◽  
Common Ancestor ◽  
Genomic Analysis ◽  
Eukaryotic Cell ◽  
Model System ◽  
Human Cells ◽  
Actin Assembly ◽  
Cell Type ◽  
Cytoplasmic Microtubules ◽  
Work Supports

ABSTRACTMuch of our current understanding of actin-driven phenotypes in eukaryotes has come from the “yeast to human” opisthokont lineage, as well as the related amoebozoa. Outside of these groups lies the genus Naegleria, which shared a common ancestor with humans over a billion years ago, and includes the deadly “brain-eating amoeba.” Unlike nearly every other known eukaryotic cell type, Naegleria amoebae are thought to lack cytoplasmic microtubules. The absence of microtubules suggests that these amoebae rapidly crawl and phagocytose bacteria using actin alone. Although this makes Naegleria a powerful system to probe actin-driven functions in the absence of microtubules, surprisingly little is known about Naegleria’s actin cytoskeleton. Here, we use microscopy and genomic analysis to show that Naegleria amoebae have an extensive actin cytoskeletal repertoire, complete with nucleators and nucleation promoting factors. Naegleria use this cytoskeletal machinery to generate Arp2/3-dependent lamellar protrusions, which correlate with the capacity to migrate and phagocytose bacteria. Because human cells also use Arp2/3-dependent lamellar protrusions for motility and phagocytosis, this work supports an evolutionarily ancient origin for these actin-driven processes and establishes Naegleria as a natural model system for studying microtubule-independent cytoskeletal phenotypes.

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