29.4 Discussion
There exists extremely small number of experimental investigations on
myxosporeans spores survival in the waters of different salinity. The first information appeared in 1901, when E. Linton placed representative of the fresh water
genus of Myxobolus – M. lintoni – into the sea water, in which its spores could
without any harm for them exist 10 days (Linton, 1901). The papers of M. Auerbach
(Auerbach 1907, 1909) are also known: he conducted an experiment on effect of the
fresh water on representative of the same genus Myxobolus – eurihaline parasite
M. aeglefini from cods. It appeared that the given parasite species became a real
oceanic species, spores of which perished after more than 12-h being in the fresh
water. But spores of parasites Fundulus heteroclitus – Myxidium folium, Myxobolus
subthecalis, M. funduli, M. bilineatum had similar life period in the fresh water and
in 1% solution of the cooking salt (Bond 1938). As for the data on survival of the
spores of just marine myxosporeans species in water of different salinity, such data
are absent completely. In a whole there exists an opinion that marine myxosporeans
are studied worse than these fresh water ones, and the main is that they underwent
ecological analysis to the less extend (Schulman et al. 1997).
In experiment we conducted about half of the marine myxosporeans K. nova
species already at the third day felt negative influence of the fresh water, expressed
in deformation of spores in cysts isolated from muscles. And this took place despite
the fact that spores are very firm and theoretically had to preserve themself longer in
the foreign medium. It is well known that K. nova bears non-considerable desalination and is much more abundant in the mesohaline shallow Sea of Azov, if
compared with the Black Sea. But clean fresh water is a factor effecting negatively
composition and condition of spores of the given parasite under its direct contact
with foreign medium. When the parasite spores are in the muscle tissue under
temperature higher than in refrigerator percentage of anomalous spores in the sea
water is higher than it is with cysts isolated from muscles in the sea water in
refrigerator and practically is similar with a share of deformed spores in muscles
placed into fresh water, kept under natural weather conditions. The biochemical
medium of the host organism softens the fresh water negative influence on K. nova
spores.
It is known that myxosporeans spores changeability having place in nature is
often connected with environment unfavorable conditions effect on them
(Schulman et al. 1997). It is expressed in changes of spores size and their form
and construction. The fact of deformation of Myxidium giardi spores from the
New Zealand eels from the lake Otomangakau with unfavorable conditions, and
absence of polar filaments shooting in the anomalous spores placed into alkaline
solution like in our data were described by P. M. Hine (Hine 1978). He connected
disturbance of normal life activity in ugly spores with changes in their chemical
composition (vanishing of magnesium in valves) and with their functional activity
(impossible extrusion). There are most often changes in a number of valves and
polar capsules in the many-valves myxosporens spores. Deformation and darkening
29 Effect of Water Different Salinity on the Morphology of Kudoa nova. . .
501
There exists extremely small number of experimental investigations on
myxosporeans spores survival in the waters of different salinity. The first information appeared in 1901, when E. Linton placed representative of the fresh water
genus of Myxobolus – M. lintoni – into the sea water, in which its spores could
without any harm for them exist 10 days (Linton, 1901). The papers of M. Auerbach
(Auerbach 1907, 1909) are also known: he conducted an experiment on effect of the
fresh water on representative of the same genus Myxobolus – eurihaline parasite
M. aeglefini from cods. It appeared that the given parasite species became a real
oceanic species, spores of which perished after more than 12-h being in the fresh
water. But spores of parasites Fundulus heteroclitus – Myxidium folium, Myxobolus
subthecalis, M. funduli, M. bilineatum had similar life period in the fresh water and
in 1% solution of the cooking salt (Bond 1938). As for the data on survival of the
spores of just marine myxosporeans species in water of different salinity, such data
are absent completely. In a whole there exists an opinion that marine myxosporeans
are studied worse than these fresh water ones, and the main is that they underwent
ecological analysis to the less extend (Schulman et al. 1997).
In experiment we conducted about half of the marine myxosporeans K. nova
species already at the third day felt negative influence of the fresh water, expressed
in deformation of spores in cysts isolated from muscles. And this took place despite
the fact that spores are very firm and theoretically had to preserve themself longer in
the foreign medium. It is well known that K. nova bears non-considerable desalination and is much more abundant in the mesohaline shallow Sea of Azov, if
compared with the Black Sea. But clean fresh water is a factor effecting negatively
composition and condition of spores of the given parasite under its direct contact
with foreign medium. When the parasite spores are in the muscle tissue under
temperature higher than in refrigerator percentage of anomalous spores in the sea
water is higher than it is with cysts isolated from muscles in the sea water in
refrigerator and practically is similar with a share of deformed spores in muscles
placed into fresh water, kept under natural weather conditions. The biochemical
medium of the host organism softens the fresh water negative influence on K. nova
spores.
It is known that myxosporeans spores changeability having place in nature is
often connected with environment unfavorable conditions effect on them
(Schulman et al. 1997). It is expressed in changes of spores size and their form
and construction. The fact of deformation of Myxidium giardi spores from the
New Zealand eels from the lake Otomangakau with unfavorable conditions, and
absence of polar filaments shooting in the anomalous spores placed into alkaline
solution like in our data were described by P. M. Hine (Hine 1978). He connected
disturbance of normal life activity in ugly spores with changes in their chemical
composition (vanishing of magnesium in valves) and with their functional activity
(impossible extrusion). There are most often changes in a number of valves and
polar capsules in the many-valves myxosporens spores. Deformation and darkening
29 Effect of Water Different Salinity on the Morphology of Kudoa nova. . .
501