JP3383223B2 - Methods for detecting harmful plankton - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting harmful airborne organisms, and more particularly to a method for detecting plankton harmful to pearl oysters.

[0002] in the background West coastal waters, post-war industrial development, due to the concentration of the population to the cities, pollution and eutrophication of water quality has progressed rapidly, began to red tide occurs frequently. As a result, a large amount of aquatic products such as aquaculture were killed, causing serious damage to the fishing industry. The number of red tides increased rapidly with high economic growth and gradually decreased after 1978, but it is still occurring every year (T.Honjo, Rev.Fish.Sci., 2,225).
-253 (1994); Y. Fukuyo et al., Uchida Rokakuho (Toky
o), p407 (1990)). In particular, a new species of algae requested in 1988,
Heterocapsa circularisquama (T.Horiguchi, Phycol.R
es., 43,129-136 (1995)) began to form red tide,
It causes mortality of fish such as pearl oysters and clams and causes many fisheries damages every year (Chihiro Yamamoto and Yoshioki Tanaka, Fukuoka Suisen Kenkyuho, 16,43-44 (1990); Yukihiko Matsuyama et al., Nippo
n Suisan Gakkaishi, 61, 35-41 (1995)). However, when a red tide occurs, it takes a lot of time and skill to collect water and identify and count plankton species, so it is very difficult to take immediate damage control measures.

Since shellfish change their opening and closing movements depending on their habitat conditions, detection of pollutants in seawater using this fact has been reported. Kramer analyzes the response of shellfish to pollutants in seawater (Baldwin, IGand Kramer, KJM, Biom.
onitoring of Coastal Waters and Estuaries, CRC Pres
S., Boca Raton, FL, 1-28 (1994)), Gainey and Shamway have investigated the response of shellfish to the toxic plankton Alexandrium (Gainey Jr. LE & SEShumway, J. Shellfish Re
s, 7,623-628 (1988)). Fujii is investigating the effects of tidal waves on the movement of the shell adductor muscle (T.Fujii, Bulle
tin of the Japanese Society of Scientific Fisherie
s, 43 (7), 901 (1977)).

Kramer attaches two small coils to both shells of a mussel as a transmitter and a receiver, and a closed shell causes a signal to be transmitted from the transmitter to the receiver and sends the signal from the receiver to land. Therefore, an electrical engineering method for detecting abnormality was used. In addition, Fujii attaches a U-shaped metal plate with putty so as to straddle both shells of the shell, and detects strain of the metal piece caused by the opening and closing movement of the shell with a strain gauge to detect the movement of the shell did.

[0005]

SUMMARY OF THE INVENTION The present inventors have now identified that floating organisms with an extremely low cell density can be detected by measuring changes in the action potential of the adductor muscle of the pearl oyster, and that they have been identified by observing the waveform of the action potential. It was found that the floating species of An object of the present invention is to provide a more sensitive method for detecting harmful airborne organisms and a method for discriminating the airborne organism species.

[0006] The present invention method for detecting harmful plankton shellfish belonging to bivalves by the shellfish belonging to bivalves (Bi valvia) is contacted with a sample and then measuring the change in action potential of the muscle of the shellfish , Which includes.

The detection method according to the present invention can detect pests with extremely low cell numbers. Therefore, according to the detection method of the present invention, it is possible to detect the floating organism that causes the red tide at an extremely early stage.

[0008]

DETAILED DESCRIPTION OF THE INVENTION In the detection method according to the present invention,
First, a shellfish belonging to Bivalvia is brought into contact with the sample. Samples can be collected from, but are not limited to, the sea areas and aquaculture ponds that monitor the fishing ground environment. For example, a mode in which a shellfish belonging to a bivalve mollusc is fixed in a sea area or a culture pond where monitoring is performed is also included in “contacting with a sample”.

[0009] Examples of the shell belonging to bivalves, airfoil eyes of marine bivalve shellfish that belong to the (Pteriomorphia) (for example, pearl oyster belonging to the warbler Guy family (Pteridae), mytilid (My tilidae) belonging to the mussels, Pectinidae family ( P
ectinidae ), as well as oysters ( Ostreidse ) and Marsdalidae ( V)
Shin valve gill eyes belonging to clams and clams) and freshwater bivalves belonging to Eneridae) (shellfish belonging to Eulamellibranchia) (e.g., Ikechougai and mussels belonging to mussels family (Unionidae), include Mashijimi) belonging to Shijimigai family (Corbiculidae) .

In the detection method of the present invention, the change in action potential of the muscle of the shellfish which is brought into contact with the sample is measured. Specifically, this can be done by observing the number or shape of the muscle action potential spikes. In the detection method according to the present invention, for example, when 4 or more spikes of the muscle action potential are observed per 15 minutes, it can be determined that a floating organism harmful to the shellfish is present in the sample. As the muscle of the shellfish for which the muscle action potential is to be measured, a so-called scallop muscle, that is, the adductor muscle can be used.

The change in muscle action potential can be measured according to the following method. First, insert two or three (+ pole, -pole, GND (ground)) electrodes directly from the rear part of the bivalve molluscs, or insert a small hole (0.3
Open ~ 1 mm), insert the electrode through the shell into the adductor muscle,
Fix with an adhesive such as dental cement or epoxy resin.
The material of the electrode may be silver-silver chloride, silver, platinum, stainless steel or the like. The diameter of the electrode is 0.1 to 0.5 mm, preferably 0.2 to 0.3 mm. The length of the inserted electrode is
Although it depends on the age (or size) of the shellfish and the size of the adductor muscle, a 2-year mother shell can be used at 2 to 8 mm. The muscle action potential is measured by connecting an electrode and a transmitter, or by connecting a lead wire directly to a measuring device and measuring the muscle action potential generated by the activity of the adductor muscle in the shell.

In the present invention, "floating organisms harmful to shellfish" refers to floating organisms that interfere with survival, reproduction and growth of shellfish, and most of them can cause red tide. In addition, "floating organisms" include not only phytoplankton but also zooplankton.

The floating organisms that can be detected by the detection method according to the present invention include dinoflagellates ( Dinophyceae ) and rafidoalgae ( Rhaphidop ) when pearl oysters are used as test subjects.
hyce ae ) and floating organisms, especially Heteroca
psa circularisquama , Chatt onella antiqua , Gymnodin
ium mikimotoi , Gymnodinium catenatum , Cochlodini um
polykrikoides , Alexandrium tamarense , Alexandrium
catenells , and Chattonella marina . Note that Chattonella antiqua is classified not only as a rafido algae but also as a green monas ( Chloromonadida ).

It goes without saying that the detection method according to the present invention can be used for monitoring the fishing ground environment not only for pearl oysters but also for pearl oysters, pearl oysters, oysters, mussels, clams and the like, even when pearl oysters are used as test subjects.

Monitoring of the fishing ground environment can be carried out by transmitting a change in the muscle action potential of the bivalve fixed to the fishing ground to a manned facility by a transmitter and analyzing the input signal received by the receiver. Of course, it is also possible to directly analyze the change in the muscle action potential without using the transmission / reception device. The analysis can be performed artificially through a monitor or by an analysis device. The analysis device may also be connected to an alarm device, which can automatically generate an alarm when a specific signal is input.

The bivalves may be fixed to the fishing ground in a cultivated basket suspended on a raft floated offshore, or in a container filled with seawater which is pumped to the land by a pump. The latter container may be provided with an intake and a drain, in which case fresh seawater is always pumped into the container.

According to the present invention, it is possible to observe the waveform of the spike of the muscle action potential and discriminate the type of floating organisms from the waveform. For example, Heterocapsa circularisquama
Waveforms and Chattonell in the presence of water in the sample
The spike waveforms when a antiqua is present in the sample are clearly different, as shown in FIGS. Therefore, the type of floating organisms present in the sample can be specified from the specificity of the waveform.

[0018]

[Example] An oyster bay pearl oyster ( Pinctada ) as an experimental shellfish
fucata ) 2 year old shellfish was used. Harmful red tide plankton Heterocapsa circularisquama , Chatton
El la antiqua , Heterosigma akashiwo , and four kinds of diet plankton, Pavlovalutheri , were used.

A silver wire having a diameter of 0.2 mm and a length of 5 mm, in which a part of the tip was left and the other part was covered with an epoxy resin, was used as an electrode, and a silver wire having a diameter of 0.3 mm was used as a conducting wire for insulation through a silicon tube. Three electrodes were attached to the detrusor muscle of the shell that opened the shell from the opposite side of the heart so as to be perpendicular to the muscle fibers. The pearl oyster equipped with electrodes was placed on a plastic net with its mouth facing upward and placed in an acrylic experimental water tank having a vent hole and a water inlet / outlet port as shown in FIG. 1μ in diameter
1 liter of seawater filtered with a m filter was poured into a water tank to stabilize the muscle potential change under weak aeration, and then the muscle potential response was recorded for 30 minutes to 1 hour, which was used as a control.

After recording the control, half of the filtered seawater in the experimental aquarium was carefully drained and 500 ml of the red tide organism suspension adjusted to the desired cell density was carefully injected. The myoelectric potential response was recorded for approximately 30 minutes while the cells were uniformly suspended by gentle aeration. The cell densities tested were 5 to 1,000 cells / m for H. circularisquama , respectively.
1, C.antiqua is 100-800 cells / ml, H.akashiw
o was 1,000 to 50,000 cells / ml, and P. lutheri was 1,000 to 100,000 cells / ml. The electric potential was measured using a Dynascope DS3140 type electrocardiograph manufactured by Fukuda Denshi Co., Ltd. in an incubator at 23 ° C. with a dark curtain.

FIG. 2 shows an electromyogram of H. circularisquama 5-25 cells / ml exposure group. In this exposure zone, no spikes appeared at all in the control, whereas many clear spikes appeared at the lowest density of 5 cells / ml, and almost the same number of spikes appeared at 10 and 25 cells / ml. Appeared.

The myoelectric potential spike upon exposure to C. antiqua is shown in FIG. At a cell density of 100 to 800 cells / ml, the number of spikes was higher than that of the control group. Also,
The waveform of this spike was different from that in FIG.

The average number of spikes per 15 minutes when exposed to the plankton tested here is shown in Table 1.

[0024]

[Table 1]

In the exposed area of H. circularisquama, the number of spikes increased slightly as the cell density increased,
Instead, it decreased at 1,000 cells / ml. As described above, pearl oysters showed a spike number higher than that of the control group in all cell densities, and sensitively reacted even at a low cell density of 5 cells / ml. When exposed to C. antiqua , the number of spikes was about 5 times that of the control group at all cell densities. On the other hand, in the H. akashiwo exposure group, no difference from the control group was observed as in the P. luther exposure group.

By measuring the muscular potential of pearl oysters , H. circularisquama makes seawater appear to be colored at a cell density of 700 cells / ml (Yukihiko Matsuyama et al., “ Heteroca of Hiroshima Bay”).
psa circularisquama red tide ”, Research Report of the Fisheries Research Institute of the Nansei Sea Area, 30,189-207 (1997)) and the pearl oyster juvenile clam 5
0 cells / ml (K. Nagai et al., Aquaculture, 144, 14
9-154 (1996)), this species can be detected at a much lower density.
Therefore, the red tide generation preparation stage can be monitored. Also C.anti
Since the number of spikes increased with respect to qua and the myoelectric spikes showed a waveform that was clearly different from those of the other three species, this species can be detected separately from other species of plankton. See also H.ak
The absence of any abnormal reaction in the adductor muscle to ashiwo and P. lutheri may be related to the active feeding of the pearl oysters on these two species.

[Brief description of drawings]

FIG. 1 is a diagram showing an experimental water tank used in Examples.

FIG. 2 is a diagram showing an electromyogram of pearl oyster adductor muscle when Heterocapsa circularisquama was exposed. Time indicates the time after injection of the sample.

FIG. 3 is a diagram showing an electromyogram of pearl oyster adductor muscle when exposed to Chattonella antiqua . Time indicates the time after injection of the sample.

[Explanation of symbols]

1 electrode 2 vents 3 Plankton inlet 4 drainage outlet 5 pearl oysters

─────────────────────────────────────────────────── --Continued from the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) A01K 61/00 A01K 67/00 G01N 33/00-33/18 JISST file (JOIS)

Claims (7)

(57) [Claims] 1. A method for detecting floating organisms harmful to shellfish belonging to Bivalvia, which comprises contacting the shellfish belonging to Bivalvia with a sample and then measuring the change in action potential of the muscle of the shellfish. . 2. The detection method according to claim 1, wherein the muscle of the shellfish is the adductor muscle. 3. The shellfish belonging to the bivalve molluscs is pearl oyster,
The detection method according to claim 1. 4. Floating organisms harmful to pearl oysters are dinoflagellates ( Dinophyceae ) and rafido algae ( Rhaphidophyce ).
The detection method according to claim 3, which is a floating organism belonging to ae ). 5. A floating organism harmful to pearl oysters is Heteroca.
a psa circularisquama or Chatt onella antiqua, detection method of claim 3. 6. A method of observing a waveform of a muscle action potential spike, and discriminating and detecting a species of a floating organism from the waveform,
The detection method described in. 7. Heterocapsa circularisquama and Chattonel
The detection method according to claim 6, wherein the detection is performed by discriminating between la antiqua .