Vanadocytes, cells hold the key to resolving the highly selective accumulation and reduction of vanadium in ascidians

  title={Vanadocytes, cells hold the key to resolving the highly selective accumulation and reduction of vanadium in ascidians},
  author={Hitoshi Michibata and Taro Uyama and Tatsuya Ueki and Kan Kanamori},
  journal={Microscopy Research and Technique},
Since Henze discovered vanadium in the blood (or coelomic) cells of an ascidian in 1911, this unusual phenomenon has attracted the interest of many investigators. [] Key Result Of the approximately 10 types of blood cells, a combination of cell fractionation and neutron-activation analysis revealed that the signet ring cells were the true vanadocytes. In the vanadocytes, 97.6% of the vanadium is in the +3 oxidation state (III).
The ecophysiology of iron and vanadium accumulation by North Atlantic ascidians
This thesis examines the seasonal variation in vanadium and iron concentrations of two Phlebobranch ascidians, Ciona intestinalis and Ascidia callosa, which accumulate vananium and iron, and a Stolidobranch Ascidian, Halocynthia pyriformis, which accumulates iron only.
Hyper-Accumulation of Vanadium in Polychaetes
The present chapter summarizes the current knowledge on vanadium accumulation in polychaetes, with special emphasis on tube-dwelling fan worms of the Sabellidae family, and suggests that the elevated levels of vanadium in branchial filaments of sabellids can act as chemical deterrents against predation in more exposed tissues.
Bioaccumulation of Copper Ions by Escherichia coli Expressing Vanabin Genes from the Vanadium-Rich Ascidian Ascidia sydneiensis samea
Data showed that the metal-binding proteins vanabin1 and vanabin2 bound copper ions directly and enhanced the bioaccumulation of copper ions by E. coli.
Hyperaccumulation of vanadium in the Antarctic polychaete Perkinsiana littoralis as a natural chemical defense against predation
The hyperaccumulation of toxic metals might represent a common antipredatory strategy for unpalatable branchial crowns of sabellid polychaetes, as recently hypothesized also for the high concentrations of arsenic in the Mediterranean Sabella spallanzanii.


The Mechanism of Accumulation of Vanadium by Ascidians: Some Progress towards an Understanding of this Unusual Phenomenon
Examining the vanadium contents of several tissues from 20 ascidian species, collected not only from Japanese waters but also from the Mediterranean since about 18 years ago, using an extremely sensitive method, namely, neutron-activation analysis, found the highest concentration of vanadium, 350 mM, in the blood cells of Ascidia gemmata which belongs to the suborder Phiebobranchia.
Contents of vanadium and sulphur in the blood cells of Ascidia mentula and Ascidiella aspersa
The tunic of ascidians also contains cells rich in vanadium and sulphuric acid and roles for them in anti-fouling and anti-predation have been considered (Stoecker, 1980 a, b ).
Identification of a Vanadium-Associated Protein from the Vanadium-Rich Ascidian, Ascidia sydneiensis samea
Using a combined technique of anion exchange column and atomic absorption spectrometry, a vanadium-associated protein (VAP) is extracted from the blood cells of the ascidian Ascidia sydneiensis samea and it is revealed that VAP is composed of at least two types of peptides and is localized in the cytoplasm of the vanadocytes.
Intracellular Sites of Activity in the Histogenesis of Tunicate Vanadocytes
It is concluded that the formation of haemovanadin in several separate stages is the result of the activity of vacuoles whose membranes change their specialized enzymic and permeability properties, while the vacuole retain their identity.
The amounts of total vanadium and vanadyl (+4) species contained in each blood cell type of ascidians were determined under a nitrogen atmosphere, using a combined approach of cell fractionation and
Immunological detection of a vacuolar-type H(+)-ATPase in vanadocytes of the ascidian Ascidia sydneiensis samea.
An immunological search for a H(+)-ATPase in the vacuolar membranes of the signet ring cells, as a first step in attempts to clarify the energetics of the accumulation of vanadium by these cells, confirmed that specific antigens in ascidian blood cells actually reacted with the antibodies.
Glucose-6-Phosphate Dehydrogenase in the Pentose Phosphate Pathway Is Localized in Vanadocytes of the Vanadium-Rich Ascidian, Ascidia sydneiensis samea
The present study revealed the existence of glucose-6-phosphodehydrogenase (G6PDH), the first enzyme to produce NADPH in the pentose phosphate pathway, in vanadocytes of a vanadium-rich ascidian, and suggested that G 6PDH conjugates the reduction of vanadium from the +5 through to the +4 oxidation state in van adocytes of ascidians.
The Bloodcells of the Ascidian, Phallusia Mammillata
The structure, histochemistry, and histogenesis of the blood-cells of Phallusia mammillata (Cuvier) have been investigated. Primitive lymphocytes give rise, by a series of transition stages, to
Separation of vanadocytes: Determination and characterization of vanadium ion in the separated blood cells of the ascidian, Ascidia ahodori
On the basis of a Ficoll gradient for cell fractionation, neutron activation analysis of vanadium ion, and ESR spectra of oxovanadium ion in blood cells, the signet ring cells are the most likely “vanadocytes” in Ascidia ahodori.