scholarly journals Responses to mechanically and visually cued water waves in the nervous system of the medicinal leech

2017 ◽  
Author(s):  
Andrew M. Lehmkuhl ◽  
Arunkumar Muthusamy ◽  
Daniel A. Wagenaar
Keyword(s):  
Nervous System ◽  
Cell Response ◽  
Water Waves ◽  
Water Movement ◽  
Medicinal Leech ◽  
Cell System ◽  
Visual Modality ◽  
Low Frequencies ◽  
Hirudo Verbana ◽  
Aquatic Predators

Summary statementCues from water movement help aquatic predators find their prey. We study how the nervous system of the medicinal leech processes visual and mechanical information derived from surface waves.AbstractSensitivity to water waves is a key modality by which aquatic predators can detect and localize their prey. For one such predator, the medicinal leech, Hirudo verbana, behavioral responses to visual and mechanical cues from water waves are well documented. Here, we quantitatively characterized the response patterns of a multisensory interneuron, the S cell, to mechanically and visually cued water waves. The frequency dependence of the S-cell response matched the behavioral response well, in that sensitivity was higher for low frequencies in the visual modality and for high frequencies in the mechanical modality. We demonstrated that neither the cephalic ganglia nor the tail brain is required for the S cell to respond to visually cued water waves. The direction of spike propagation within the S- cell system did follow the direction of wave propagation under certain circumstances, but it is unlikely that downstream neuronal targets can use this information. In terms of overall firing rate, the S cell response was not direction selective. Accordingly we propose a role for the S cell in the detection of waves but not in the localization of their source.

scholarly journals The Draft Reference Genome for Hirudo verbana, the Medicinal Leech

2020 ◽  
Author(s):  
Riley T. Paulsen ◽  
Diing D.M. Agany ◽  
Jason Petersen ◽  
Christel M. Davis ◽  
Erik A. Ehli ◽  
...  
Keyword(s):  
Nervous System ◽  
Genome Assembly ◽  
Draft Genome ◽  
Model Organism ◽  
Medicinal Leech ◽  
Comparative Approach ◽  
Neural Pathways ◽  
Sequencing Platform ◽  
Draft Genome Assembly ◽  
Hirudo Verbana

The medicinal leech, Hirudo verbana, is a powerful model organism for investigating fundamental neurobehavioral processes. The well-documented arrangement and properties of H. verbana’s nervous system allows changes at the level of specific neurons or synapses to be linked to physiological and behavioral phenomena. Juxtaposed to the extensive knowledge of H. verbana’s nervous system is a limited, but recently expanding, portfolio of molecular and multi-omics tools. Together, the advancement of genetic databases for H. verbana will complement existing pharmacological and electrophysiological data by affording targeted manipulation and analysis of gene expression in neural pathways of interest. Here, we present the first draft genome assembly for H. verbana, which is approximately 250 Mbp in size and consists of 61,282 contigs. Whole genome sequencing was conducted using an Illumina sequencing platform followed by genome assembly with CLC-Bio Genomics Workbench and subsequent functional annotation. Ultimately, the diversity of organisms for which we have genomic information should parallel the availability of next generation sequencing technologies to widen the comparative approach to understand the involvement and discovery of genes in evolutionarily conserved processes. Results of this work hope to facilitate comparative studies with H. verbana and provide the foundation for future, more complete, genome assemblies of the leech.

scholarly journals An annotated CNS transcriptome of the medicinal leech, Hirudo verbana: De novo sequencing to characterize genes associated with nervous system activity

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0201206 ◽  
Author(s):  
Adam J. Northcutt ◽  
Eva K. Fischer ◽  
Joshua G. Puhl ◽  
Karen A. Mesce ◽  
David J. Schulz
Keyword(s):  
Nervous System ◽  
De Novo ◽  
Medicinal Leech ◽  
De Novo Sequencing ◽  
System Activity ◽  
Nervous System Activity ◽  
Hirudo Verbana

scholarly journals Responses to mechanically and visually cued water waves in the nervous system of the medicinal leech

2018 ◽  
Vol 221 (4) ◽  
pp. jeb171728 ◽  
Author(s):  
Andrew M. Lehmkuhl ◽  
Arunkumar Muthusamy ◽  
Daniel A. Wagenaar
Keyword(s):  
Nervous System ◽  
Water Waves ◽  
Medicinal Leech

Seasonal Bioaccumulation of Heavy Metals by Medicinal Leech Hirudo verbana

2018 ◽  
Vol 54 (5) ◽  
pp. 56-62
Author(s):  
L. V. Chornaya ◽  
L. A. Kovalchuk ◽  
N. V. Mikshevich
Keyword(s):  
Heavy Metals ◽  
Medicinal Leech ◽  
Hirudo Verbana

scholarly journals Electrospun Fiber Scaffolds for Engineering Glial Cell Behavior to Promote Neural Regeneration

2020 ◽  
Vol 8 (1) ◽  
pp. 4
Author(s):  
Devan L. Puhl ◽  
Jessica L. Funnell ◽  
Derek W. Nelson ◽  
Manoj K. Gottipati ◽  
Ryan J. Gilbert
Keyword(s):  
Nervous System ◽  
Glial Cell ◽  
Cell Response ◽  
Electrospun Fiber ◽  
Neural Regeneration ◽  
Cell Phenotype ◽  
Comprehensive Overview ◽  
Fiber Alignment ◽  
Wide Range ◽  
Fiber Scaffolds

Electrospinning is a fabrication technique used to produce nano- or micro- diameter fibers to generate biocompatible, biodegradable scaffolds for tissue engineering applications. Electrospun fiber scaffolds are advantageous for neural regeneration because they mimic the structure of the nervous system extracellular matrix and provide contact guidance for regenerating axons. Glia are non-neuronal regulatory cells that maintain homeostasis in the healthy nervous system and regulate regeneration in the injured nervous system. Electrospun fiber scaffolds offer a wide range of characteristics, such as fiber alignment, diameter, surface nanotopography, and surface chemistry that can be engineered to achieve a desired glial cell response to injury. Further, electrospun fibers can be loaded with drugs, nucleic acids, or proteins to provide the local, sustained release of such therapeutics to alter glial cell phenotype to better support regeneration. This review provides the first comprehensive overview of how electrospun fiber alignment, diameter, surface nanotopography, surface functionalization, and therapeutic delivery affect Schwann cells in the peripheral nervous system and astrocytes, oligodendrocytes, and microglia in the central nervous system both in vitro and in vivo. The information presented can be used to design and optimize electrospun fiber scaffolds to target glial cell response to mitigate nervous system injury and improve regeneration.

scholarly journals Up-regulation of Neurohemerythrin Expression in the Central Nervous System of the Medicinal Leech,Hirudo medicinalis, following Septic Injury

2004 ◽  
Vol 279 (42) ◽  
pp. 43828-43837 ◽  
Author(s):  
David Vergote ◽  
Pierre-Eric Sautière ◽  
Franck Vandenbulcke ◽  
Didier Vieau ◽  
Guillaume Mitta ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Medicinal Leech ◽  
Hirudo Medicinalis ◽  
The Central Nervous System

scholarly journals Exploring the attachment of the Mediterranean medicinal leech ( Hirudo verbana ) to porous substrates

2020 ◽  
Vol 17 (168) ◽  
pp. 20200300
Author(s):  
Tim Kampowski ◽  
Lara-Louise Thiemann ◽  
Lukas Kürner ◽  
Thomas Speck ◽  
Simon Poppinga
Keyword(s):  
High Speed ◽  
Medicinal Leech ◽  
Mechanical Tests ◽  
Artificial Substrates ◽  
Hirudo Verbana ◽  
The Mediterranean ◽  
The Rich ◽  
Attachment Mechanism ◽  
Blood Meals ◽  
Porous Substrates

Haematophagous ectoparasites must ensure a reliable hold to their host during blood meals and, therefore, have evolved a broad spectrum of versatile and effective attachment mechanisms. The Mediterranean medicinal leech ( Hirudo verbana ), for example, uses suction on both smooth and textured air-tight substrates. However, preliminary studies showed that H. verbana is also capable of attaching itself to air-permeable substrates, where suction does not work. Using high-speed videography and mechanical tests, we comparatively investigated the attachment of H. verbana on both smooth and textured air-tight as well as on porous artificial substrates, also considering the influence of mucus on sucker surfaces. In general, the leech-specific locomotion cycle did not differ between the tested surfaces, and the leeches were able to reliably attach to both air-tight and porous substrates. From our results, we conclude that suction is presumably the primary attachment mechanism of H. verbana . However, secondary mechanisms such as mechanical interlocking with surface asperities and pores or capillary forces occurring at the interface between the mucus-covered suckers and the substratum are also employed. In any case, the rich repertoire of applicable attachment principles renders the organs of H. verbana functionally highly resilient.

scholarly journals Public T-cell epitopes shared among SARS-CoV-2 variants are presented on prevalent HLA class I alleles

2021 ◽  
Author(s):  
Saskia Meyer ◽  
Isaac Blaas ◽  
Ravi Chand Bollineni ◽  
Marina Delic-Sarac ◽  
Trung T Tran ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Response ◽  
T Cell Responses ◽  
Hla Class I ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Class I ◽  
T Cell Epitopes ◽  
Low Frequencies ◽  
Cell Responses

T-cell epitopes with broad population coverage may form the basis for a new generation of SARS-CoV-2 vaccines. However, published studies on immunoprevalence are limited by small test cohorts, low frequencies of antigen-specific cells and lack of data correlating eluted HLA ligands with T-cell responsiveness. Here, we investigate CD8 T-cell responses to 48 peptides eluted from prevalent HLA alleles, and an additional 84 predicted binders, in a large cohort of convalescents (n=83) and pre-pandemic control samples (n=19). We identify nine conserved SARS-CoV-2 specific epitopes restricted by four of the most prevalent HLA class I alleles in Caucasians, to which responding CD8 T cells are detected in 70-100% of convalescents expressing the relevant HLA allele, including two novel epitopes. We find a strong correlation between immunoprevalence and immunodominance. Using a new algorithm, we predict that a vaccine including these epitopes would induce a T cell response in 83% of Caucasians. Significance Statement: Vaccines that induce broad T-cell responses may boost immunity as protection from current vaccines against SARS-CoV-2 is waning. From a manufacturing standpoint, and to deliver the highest possible dose of the most immunogenic antigens, it is rational to limit the number of epitopes to those inducing the strongest immune responses in the highest proportion of individuals in a population. Our data show that the CD8 T cell response to SARS-CoV-2 is more focused than previously believed. We identify nine conserved SARS-CoV-2 specific CD8 T cell epitopes restricted by four of the most prevalent HLA class I alleles in Caucasians and demonstrate that seven of these are endogenously presented.

Characteristics of Low-Frequency Horizontal Noise of Ocean-Bottom Seismic Data

2021 ◽  
Author(s):  
Chao An ◽  
Chen Cai ◽  
Lei Zhou ◽  
Ting Yang
Keyword(s):  
Water Waves ◽  
Noise Source ◽  
Random Noise ◽  
Low Frequency ◽  
Ocean Bottom ◽  
Coherent Noise ◽  
Infragravity Waves ◽  
Low Frequencies ◽  
Bottom Currents ◽  
Ocean Bottom Seismographs

Abstract Horizontal records of ocean-bottom seismographs are usually noisy at low frequencies (< 0.1 Hz). The noise source is believed to be associated with ocean-bottom currents that may tilt the instrument. Currently horizontal records are mainly used to remove the coherent noise in vertical records, and there has been little literature that quantitatively discusses the mechanism and characteristics of low-frequency horizontal noise. In this article, we analyze in situ ocean-bottom measurements by rotating the data horizontally and evaluating the coherency between different channels. Results suggest that the horizontal noise consists of two components, random noise and principle noise whose direction barely changes in time. The amplitude and the direction of the latter are possibly related to the intensity and direction of ocean-bottom currents. Rotating the horizontal records to the direction of the principle noise can largely suppress the principle noise in the orthogonal horizontal channel. In addition, the horizontal noise is incoherent with pressure, indicating that the noise source is not ocean surface water waves (infragravity waves). At some stations in shallow waters (<300 m), horizontal noise around 0.07 Hz is found to be linearly proportional to the temporal derivative of pressure, which is explained by forces of added mass due to infragravity waves.

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