TY - JOUR
T1 - Immunological detection of a vacuolar‐type H+‐ATPase in vanadocytes of the ascidian Ascidia sydneiensis samea
AU - Uyama, Taro
AU - Moriyama, Yoshinori
AU - Futai, Masamitsu
AU - Michibata, Hitoshi
PY - 1994/10/1
Y1 - 1994/10/1
N2 - Ascidians belonging to the family Ascidiidae are known to accumulate vanadium from seawater in their blood cells, concentrating vanadium by a factor of 107. Among several different types of blood cell, the signet ring cells have both high levels of vanadium and a low pH. These observations suggest the possibility that proton ions concentrated by a H+‐ATPase are energetically linked to the accumulation of vanadium. In the present experiments, therefore, we made an immunological search for a H+‐ATPase in the vacuolar membranes of the signet ring cells, as a first step in our attempts to clarify the energetics of the accumulation of vanadium by these cells. Antibodies raised against the 72‐kDa and 57‐kDa subunits of a vacuolar‐type H+‐ATPase from bovine chromaffin granules reacted with the vacuolar membranes of signet ring cells. Immunoblotting analysis confirmed that specific antigens in ascidian blood cells actually reacted with the antibodies. Furthermore, addition of bafilomycin A1, a specific inhibitor of vacuolar‐type H+‐ATPase, inhibited the uptake of protons by the vacuoles of signet ring cells. Thus, the addition of bafilomycin A1 inhibited the pumping function of the vacuoles of signet ring cells, with resultant neutralization of the contents of the vacuoles. © 1994 Wiley‐Liss, Inc.
AB - Ascidians belonging to the family Ascidiidae are known to accumulate vanadium from seawater in their blood cells, concentrating vanadium by a factor of 107. Among several different types of blood cell, the signet ring cells have both high levels of vanadium and a low pH. These observations suggest the possibility that proton ions concentrated by a H+‐ATPase are energetically linked to the accumulation of vanadium. In the present experiments, therefore, we made an immunological search for a H+‐ATPase in the vacuolar membranes of the signet ring cells, as a first step in our attempts to clarify the energetics of the accumulation of vanadium by these cells. Antibodies raised against the 72‐kDa and 57‐kDa subunits of a vacuolar‐type H+‐ATPase from bovine chromaffin granules reacted with the vacuolar membranes of signet ring cells. Immunoblotting analysis confirmed that specific antigens in ascidian blood cells actually reacted with the antibodies. Furthermore, addition of bafilomycin A1, a specific inhibitor of vacuolar‐type H+‐ATPase, inhibited the uptake of protons by the vacuoles of signet ring cells. Thus, the addition of bafilomycin A1 inhibited the pumping function of the vacuoles of signet ring cells, with resultant neutralization of the contents of the vacuoles. © 1994 Wiley‐Liss, Inc.
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U2 - 10.1002/jez.1402700204
DO - 10.1002/jez.1402700204
M3 - Article
C2 - 7964552
AN - SCOPUS:0028518920
VL - 270
SP - 148
EP - 154
JO - Journal of Experimental Zoology Part A: Comparative Experimental Biology
JF - Journal of Experimental Zoology Part A: Comparative Experimental Biology
SN - 0022-104X
IS - 2
ER -