The Pericardial Body of Ciona intestinalis Contains Hemocytes and Degenerating Muscle Cells, But No Parasites

Abstract Purpose A ventral heart positioned posterior to the branchial basket and equipped with a pericardium is homologous in tunicates and their sister group, the craniates, yet the tunicate model organism Ciona intestinalis features a pericardial body, a structure peculiar to few ascidian species. Here, we set out to distinguish between two competing hypotheses regarding the function of the pericardial body found in the literature: (H1) The pericardial body performs a role in the removal of dysfunctional myocardial cells, and (H2) it is a specialized niche of the immune system involved in defense against parasites. Methods We used histological techniques, transmission electron microscopy, and PCR-based gene sequencing to investigate whether individual ascidians parasitized with apicomplexan protists show signs of infections within the pericardial body. Results In individuals of C. intestinalis from the German North Sea infested with apicomplexan protists, the pericardial body contains numerous myocardial cells in various stages of degeneration while no remnants of parasitic cells could be identified. Conclusion Thus, we conclude that H2—the pericardial body is a specialized niche of the immune system involved in defense against parasites—can be refuted. Rather, our observations support H1, the hypothesis that the pericardial body performs a role in the removal of dysfunctional myocardial cells.

Download Full-text

“Candidatus Bacilloplasma,” a Novel Lineage of Mollicutes Associated with the Hindgut Wall of the Terrestrial Isopod Porcellio scaber (Crustacea: Isopoda)

Applied and Environmental Microbiology ◽

10.1128/aem.02468-06 ◽

2007 ◽

Vol 73 (17) ◽

pp. 5566-5573 ◽

Cited By ~ 58

Author(s):

Rok Kostanjšek ◽

Jasna Štrus ◽

Gorazd Avguštin

Keyword(s):

Electron Microscopy ◽

Sequence Similarity ◽

Mycoplasma Hominis ◽

Sister Group ◽

Phylogenetic Position ◽

Rrna Gene ◽

Porcellio Scaber ◽

Terrestrial Isopod ◽

Transmission Electron ◽

A Cell

ABSTRACT Pointed, rod-shaped bacteria colonizing the cuticular surface of the hindgut of the terrestrial isopod crustacean Porcellio scaber (Crustacea: Isopoda) were investigated by comparative 16S rRNA gene sequence analysis and electron microscopy. The results of phylogenetic analysis, and the absence of a cell wall, affiliated these bacteria with the class Mollicutes, within which they represent a novel and deeply branched lineage, sharing less than 82.6% sequence similarity to known Mollicutes. The lineage has been positioned as a sister group to the clade comprising the Spiroplasma group, the Mycoplasma pneumoniae group, and the Mycoplasma hominis group. The specific signature sequence was identified and used as a probe in in situ hybridization, which confirmed that the retrieved sequences originate from the attached rod-shaped bacteria from the hindgut of P. scaber and made it possible to detect these bacteria in their natural environment. Scanning and transmission electron microscopy revealed a spherically shaped structure at the tapered end of the rod-shaped bacteria, enabling their specific and exclusive attachment to the tip of the cuticular spines on the inner surface of the gut. Specific adaptation to the gut environment, as well as phylogenetic positioning, indicate the long-term association and probable coevolution of the bacteria and the host. Taking into account their pointed, rod-shaped morphology and their phylogenetic position, the name “Candidatus Bacilloplasma” has been proposed for this new lineage of bacteria specifically associated with the gut surface of P. scaber.

Download Full-text

Computational Model Informs Effective Control Interventions against Y. enterocolitica Co-Infection

Biology ◽

10.3390/biology9120431 ◽

2020 ◽

Vol 9 (12) ◽

pp. 431

Author(s):

Reihaneh Mostolizadeh ◽

Andreas Dräger

Keyword(s):

Growth Rate ◽

Immune System ◽

Control Strategies ◽

Model Organism ◽

Effective Control ◽

Host Immune System ◽

Gastrointestinal Infections ◽

Robert Koch Institute ◽

Bacteria Growth ◽

Host Immune Responses

The complex interplay between pathogens, host factors, and the integrity and composition of the endogenous microbiome determine the course and outcome of gastrointestinal infections. The model organism Yersinia entercolitica (Ye) is one of the five top frequent causes of bacterial gastroenteritis based on the Epidemiological Bulletin of the Robert Koch Institute (RKI), 10 September 2020. A fundamental challenge in predicting the course of an infection is to understand whether co-infection with two Yersinia strains, differing only in their capacity to resist killing by the host immune system, may decrease the overall virulence by competitive exclusion or increase it by acting cooperatively. Herein, we study the primary interactions among Ye, the host immune system and the microbiota, and their influence on Yersinia population dynamics. The employed model considers commensal bacterial in two host compartments (the intestinal mucosa the and lumen), the co-existence of wt and mut Yersinia strains, and the host immune responses. We determine four possible equilibria: disease-free, wt-free, mut-free, and co-existence of wt and mut in equilibrium. We also calculate the reproduction number for each strain as a threshold parameter to determine if the population may be eradicated or persist within the host. We conclude that the infection should disappear if the reproduction numbers for each strain fall below one, and the commensal bacteria growth rate exceeds the pathogen’s growth rate. These findings will help inform medical control strategies. The supplement includes the MATLAB source script, Maple workbook, and figures.

Download Full-text

The Influence of Bee Venom Melittin on the Functioning of the Immune System and the Contractile Activity of the Insect Heart—A Preliminary Study

Toxins ◽

10.3390/toxins11090494 ◽

2019 ◽

Vol 11 (9) ◽

pp. 494 ◽

Cited By ~ 5

Author(s):

Jan Lubawy ◽

Arkadiusz Urbański ◽

Lucyna Mrówczyńska ◽

Eliza Matuszewska ◽

Agata Światły-Błaszkiewicz ◽

...

Keyword(s):

Immune System ◽

Contractile Activity ◽

Model Organism ◽

Dependent Manner ◽

Physiological Studies ◽

Almost All ◽

First Time ◽

Dose Dependent ◽

Positive Effect

Melittin (MEL) is a basic polypeptide originally purified from honeybee venom. MEL exhibits a broad spectrum of biological activity. However, almost all studies on MEL activity have been carried out on vertebrate models or cell lines. Recently, due to cheap breeding and the possibility of extrapolating the results of the research to vertebrates, insects have been used for various bioassays and comparative physiological studies. For these reasons, it is valuable to examine the influence of melittin on insect physiology. Here, for the first time, we report the immunotropic and cardiotropic effects of melittin on the beetle Tenebrio molitor as a model insect. After melittin injection at 10−7 M and 10−3 M, the number of apoptotic cells in the haemolymph increased in a dose-dependent manner. The pro-apoptotic action of MEL was likely compensated by increasing the total number of haemocytes. However, the injection of MEL did not cause any changes in the percent of phagocytic haemocytes or in the phenoloxidase activity. In an in vitro bioassay with a semi-isolated Tenebrio heart, MEL induced a slight chronotropic-positive effect only at a higher concentration (10−4 M). Preliminary results indicated that melittin exerts pleiotropic effects on the functioning of the immune system and the endogenous contractile activity of the heart. Some of the induced responses in T. molitor resemble the reactions observed in vertebrate models. Therefore, the T. molitor beetle may be a convenient invertebrate model organism for comparative physiological studies and for the identification of new properties and mechanisms of action of melittin and related compounds.

Download Full-text

Teratogenic potential of nanoencapsulated vitamin A evaluated on an alternative model organism, the tunicate Ciona intestinalis

International Journal of Food Sciences and Nutrition ◽

10.1080/09637486.2017.1418843 ◽

2018 ◽

Vol 69 (7) ◽

pp. 805-813 ◽

Cited By ~ 1

Author(s):

Roberta Pennati ◽

Raoul Manenti ◽

Antonella Stillitano ◽

Gentile Francesco Ficetola ◽

Giorgio Scarì ◽

...

Keyword(s):

Vitamin A ◽

Alternative Model ◽

Model Organism ◽

Ciona Intestinalis ◽

Teratogenic Potential

Download Full-text

A Nodal/Eph signalling relay drives the transition from apical constriction to apico-basal shortening in ascidian endoderm invagination

Development ◽

10.1242/dev.186965 ◽

2020 ◽

Vol 147 (15) ◽

pp. dev186965

Author(s):

Ulla-Maj Fiuza ◽

Takefumi Negishi ◽

Alice Rouan ◽

Hitoyoshi Yasuo ◽

Patrick Lemaire

Keyword(s):

Cell Cycle ◽

Cell Division ◽

Ciona Intestinalis ◽

Precursor Cells ◽

Endodermal Cell ◽

Apical Constriction ◽

Fate Specification ◽

Endoderm Cell ◽

Ascidian Species ◽

Morphogenetic Event

ABSTRACTGastrulation is the first major morphogenetic event during animal embryogenesis. Ascidian gastrulation starts with the invagination of 10 endodermal precursor cells between the 64- and late 112-cell stages. This process occurs in the absence of endodermal cell division and in two steps, driven by myosin-dependent contractions of the acto-myosin network. First, endoderm precursors constrict their apex. Second, they shorten apico-basally, while retaining small apical surfaces, thereby causing invagination. The mechanisms that prevent endoderm cell division, trigger the transition between step 1 and step 2, and drive apico-basal shortening have remained elusive. Here, we demonstrate a conserved role for Nodal and Eph signalling during invagination in two distantly related ascidian species, Phallusia mammillata and Ciona intestinalis. Specifically, we show that the transition to step 2 is triggered by Nodal relayed by Eph signalling. In addition, our results indicate that Eph signalling lengthens the endodermal cell cycle, independently of Nodal. Finally, we find that both Nodal and Eph signals are dispensable for endoderm fate specification. These results illustrate commonalities as well as differences in the action of Nodal during ascidian and vertebrate gastrulation.

Download Full-text

Multiscale Distribution and Bioaccumulation Analysis of Clofazimine Reveals a Massive Immune System-Mediated Xenobiotic Sequestration Response

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01731-12 ◽

2012 ◽

Vol 57 (3) ◽

pp. 1218-1230 ◽

Cited By ~ 46

Author(s):

Jason Baik ◽

Kathleen A. Stringer ◽

Gerta Mane ◽

Gus R. Rosania

Keyword(s):

Immune System ◽

Acute Phase Response ◽

Chemotherapeutic Agent ◽

Interleukin 1 ◽

Model Organism ◽

Mycobacterial Infection ◽

Major Fraction ◽

Living Organisms ◽

Lymphatic Organs

ABSTRACTChronic exposure to some well-absorbed but slowly eliminated xenobiotics can lead to their bioaccumulation in living organisms. Here, we studied the bioaccumulation and distribution of clofazimine, a riminophenazine antibiotic used to treat mycobacterial infection. Using mice as a model organism, we performed a multiscale, quantitative analysis to reveal the sites of clofazimine bioaccumulation during chronic, long-term exposure. Remarkably, between 3 and 8 weeks of dietary administration, clofazimine massively redistributed from adipose tissue to liver and spleen. During this time, clofazimine concentration in fat and serum significantly decreased, while the mass of clofazimine in spleen and liver increased by >10-fold. These changes were paralleled by the accumulation of clofazimine in the resident macrophages of the lymphatic organs, with as much as 90% of the clofazimine mass in spleen sequestered in intracellular crystal-like drug inclusions (CLDIs). The amount of clofazimine associated with CLDIs of liver and spleen macrophages disproportionately increased and ultimately accounted for a major fraction of the total clofazimine in the host. After treatment was discontinued, clofazimine was retained in spleen while its concentrations decreased in blood and other organs. Immunologically, clofazimine bioaccumulation induced a local, monocyte-specific upregulation of various chemokines and receptors. However, interleukin-1 receptor antagonist was also upregulated, and the acute-phase response pathways and oxidant capacity decreased or remained unchanged, marking a concomitant activation of an anti-inflammatory response. These experiments indicate an inducible, immune system-dependent, xenobiotic sequestration response affecting the atypical pharmacokinetics of a small molecule chemotherapeutic agent.

Download Full-text

A Novel Biological Role of Tachykinins as an Up-Regulator of Oocyte Growth: Identification of an Evolutionary Origin of Tachykininergic Functions in the Ovary of the Ascidian, Ciona intestinalis

Endocrinology ◽

10.1210/en.2008-0323 ◽

2008 ◽

Vol 149 (9) ◽

pp. 4346-4356 ◽

Cited By ~ 42

Author(s):

Masato Aoyama ◽

Tsuyoshi Kawada ◽

Manabu Fujie ◽

Kohji Hotta ◽

Tsubasa Sakai ◽

...

Keyword(s):

Gene Expression ◽

Regulation Of Gene Expression ◽

Model Organism ◽

Ciona Intestinalis ◽

Enzymatic Activities ◽

Evolutionary Origin ◽

Phylogenetic Position ◽

Specific Expression ◽

Oocyte Growth ◽

Vitellogenic Stage

Tachykinins (TKs) and their receptors have been shown to be expressed in the mammalian ovary. However, the biological roles of ovarian TKs have yet to be verified. Ci-TK-I and Ci-TK-R, characterized from the protochordate (ascidian), Ciona intestinalis, are prototypes of vertebrate TKs and their receptors. In the present study, we show a novel biological function of TKs as an inducible factor for oocyte growth using C. intestinalis as a model organism. Immunostaining demonstrated the specific expression of Ci-TK-R in test cells residing in oocytes at the vitellogenic stage. DNA microarray and real-time PCR revealed that Ci-TK-I induced gene expression of several proteases, including cathepsin D, chymotrypsin, and carboxy-peptidase B1, in the ovary. The enzymatic activities of these proteases in the ovary were also shown to be enhanced by Ci-TK-I. Of particular significance is that the treatment of Ciona oocytes with Ci-TK-I resulted in progression of growth from the vitellogenic stage to the post-vitellogenic stage. The Ci-TK-I-induced oocyte growth was blocked by a TK antagonist or by protease inhibitors. These results led to the conclusion that Ci-TK-I enhances growth of the vitellogenic oocytes via up-regulation of gene expression and enzymatic activities of the proteases. This is the first clarification of the biological roles of TKs in the ovary and the underlying essential molecular mechanism. Furthermore, considering the phylogenetic position of ascidians as basal chordates, we suggest that the novel TK-regulated oocyte growth is an “evolutionary origin” of the tachykininergic functions in the ovary.

Download Full-text

The non-brain anterior nerve center and tentacle crown structure of Owenia borealis (Annelida, Oweniidae): the evolution of the nervous system and tentacles in Bilateria

10.21203/rs.3.rs-622783/v1 ◽

2021 ◽

Author(s):

Nadezhda Rimskaya-Korsakova ◽

Vyacheslav Dyachuk ◽

Elena Temereva

Keyword(s):

Electron Microscopy ◽

System Development ◽

Sister Group ◽

Ultrastructural Level ◽

Myoepithelial Cells ◽

Coelomic Cavity ◽

Head Region ◽

Blood Capillaries ◽

Crown Structure ◽

Transmission Electron

Abstract The Oweniidae are marine annelids with many unusual features of organ system, development, morphology, and ultrastructure. Together with magelionds, oweniids have been placed within the Palaeoannelida, a sister group to all remaining annelids. The study of this group may increase our understanding of the early evolution of annelids (including their radiation and diversification) and of the morphology of the last common bilaterian ancestor. In the current research, scanning electron microscopy revealed that the tentacle apparatus consists of 10 branched arms. The tentacles are covered by monociliary cells that form a ciliar groove that extends along the oral side of the arm base. Light, confocal, and transmission electron microscopy revealed that head region contains two circular intraepidermal nerves (outer and inner) that give rise to the neurites of each tentacle, i.e., intertentacular neurites are absent. Each tentacle contains a coelomic cavity with a network of blood capillaries. Monociliar myoepithelial cells of the tentacle coelomic cavity form both the longitudinal and the circular muscles. The structure of this myoepithelium is intermediate between simple and pseudo-stratified myepithelium. Overall, tentacles lack prominent zonality, i.e., co-localization of ciliary zones, neurite bundles, and muscles. This organization, which indicates a non-specialized tentacle crown in O. borealis and other oweniids with tentacles, is probably ancestral for annelids and for all Bilateria. The outer circular nerve of O. borealis is a dorsal medullary commissure that apparently functions as an anterior nerve center and is organized at the ultrastructural level as a stratified neuroepithelium. Given the hypothesis that the anterior nerve center of the last bilateral ancestor might be a diffuse neural plexus network, these results suggest that the ultra anatomy of that plexus brain might be a stratified neuroepithelium. Alternatively, the results could reflect the simplification of structure of the anterior nerve center in some bilaterian lineages.

Download Full-text

Dendritic cell CX3CR1 and macrophages F4/80 play a central role in between gut micro biome and inflammation in Arsenic induced mice

10.1101/2021.01.25.428065 ◽

2021 ◽

Author(s):

Chiranjeevi Tikka ◽

Ram Kumar Manthari ◽

Ruiyan Niu ◽

Zilong Sun ◽

Jundong Wang

Keyword(s):

Immune System ◽

Gut Microbiota ◽

Chronic Exposure ◽

High Throughput Sequencing ◽

Immune Cell ◽

Underlying Mechanism ◽

Sequencing Analysis ◽

Protein Levels ◽

Transmission Electron ◽

Intestinal Immune System

AbstractMicrobiota plays a crucial role to protect the intestine contrary to the harmful foreign microorganisms and organize the immune system via numerous mechanisms, which include either direct or indirect environmental factors. The underlying mechanism arsenic (As) influenced immune system and regulates inflammation by altering gut microbiome in ileum remains unclear. However, chronic exposure to arsenic (at doses of 0.15 mg or 1.5 mg or 15 mg As2O3/ L in drinking water) significantly increased mRNA and protein levels of F4/80 and CX3CR1, concurrently, the increased levels of mRNA and protein IFNγ, TNFα, IL-18 and decreased levels of IL-10 were found in both 3 and 6 months exposure periods. High-throughput sequencing analysis revealed that gut microbiota at phylum; family and taxonomical levels were showed the abundance of gut microbiota. Evidentially, the ultra-structure of intestinal villi, microbes engulfed and immune cell migration were showed by the transmission electron microscopy. Chronic exposure to As influenced the inflammation by changing immune system and altered gut microbiota. In this study we conclude that chronic exposure to As breakdown the normal gut microbial community and increase the pathogenicity, the resultant risk pathogen direct contact with intestinal immune system and regulate the inflammation.

Download Full-text

ANISEED 2019: 4D exploration of genetic data for an extended range of tunicates

Nucleic Acids Research ◽

10.1093/nar/gkz955 ◽

2019 ◽

Cited By ~ 3

Author(s):

Justine Dardaillon ◽

Delphine Dauga ◽

Paul Simion ◽

Emmanuel Faure ◽

Takeshi A Onuma ◽

...

Keyword(s):

Gene Expression ◽

Expression Profiles ◽

Model Organism ◽

Gene Expression Profiles ◽

Sister Group ◽

Model Organism Database ◽

Oikopleura Dioica ◽

Genetic Features ◽

Taxonomic Range ◽

Or Gene

Abstract ANISEED (https://www.aniseed.cnrs.fr) is the main model organism database for the worldwide community of scientists working on tunicates, the vertebrate sister-group. Information provided for each species includes functionally-annotated gene and transcript models with orthology relationships within tunicates, and with echinoderms, cephalochordates and vertebrates. Beyond genes the system describes other genetic elements, including repeated elements and cis-regulatory modules. Gene expression profiles for several thousand genes are formalized in both wild-type and experimentally-manipulated conditions, using formal anatomical ontologies. These data can be explored through three complementary types of browsers, each offering a different view-point. A developmental browser summarizes the information in a gene- or territory-centric manner. Advanced genomic browsers integrate the genetic features surrounding genes or gene sets within a species. A Genomicus synteny browser explores the conservation of local gene order across deuterostome. This new release covers an extended taxonomic range of 14 species, including for the first time a non-ascidian species, the appendicularian Oikopleura dioica. Functional annotations, provided for each species, were enhanced through a combination of manual curation of gene models and the development of an improved orthology detection pipeline. Finally, gene expression profiles and anatomical territories can be explored in 4D online through the newly developed Morphonet morphogenetic browser.

Download Full-text