JP5239069B2 - Anti-sminori disease bacteriophage and method for preventing minori disease in cultured laver - Google Patents

Description

  The present invention relates to an anti-sumirinosis bacteriophage that belongs to the genus Flavobacter and can specifically prevent pathogenic bacteria that cause sminori disease in laver to prevent sorioli disease in laver, and this anti-smolin bacteriophage The present invention relates to a method for preventing Sumiori disease in cultured laver.

  Sminori disease is known as a disease of nori seaweed cultured. Since the protoplast is discharged from the leaf body of the seaweed that has developed Sminori disease, the dried seaweed product obtained by drying the leaf body has no gloss and has little commercial value.

  By the way, conventionally, in nori culture, acid treatment for treating leaf bodies with organic acid has been carried out in order to control the algae that cause deterioration in quality and diseases. It also has an effect on prevention.

As such an acid treatment agent, Patent Document 1 described later contains a sparingly soluble organic acid such as fumaric acid and adipic acid, an acidic solution composed of an aqueous solution such as citric acid and lactic acid, and xanthan gum as a dispersant. Is disclosed.
Japanese Patent Laid-Open No. 2005-60273

However, in such an acid treatment method, it cannot be denied that the environment may be contaminated by a large amount of the acid treatment agent used.
The present invention has been made in view of such circumstances, and belongs to the genus Flavobacter, and can specifically prevent pathogenic bacteria that cause Sorioli disease in laver and prevent Sorioli disease in laver. Provided are an anti-sumirinosis bacteriophage and a method for preventing a scab of cultured seaweed using the anti-sumirinosis bacteriophage.

  The present invention described in claim 1 belongs to the genus Flavobacter, and specifically infects pathogenic bacteria causing pathogenic bacteria in seaweed, and can prevent the seaweed's pathogenic bacteria from being caused by the pathogenic bacteria. It is a bacteriophage.

According to a second aspect of the invention is characterized in that the pathogenic bacterium serving Flavobacterium Arthrobacter sp H. 14 Eruwai bacteriophage U2 specifically infect (Flavobacter sp.H14LY) (NITE AP- 398).

  The method for preventing smiring disease of cultured seaweed according to claim 3 was prepared by suspending the anti-sminoli disease bacteriophage according to claim 1 or 2 in an appropriate liquid to prepare a treatment solution and seeding the laver. A laver culture net is treated with the treatment liquid.

  According to a fourth aspect of the present invention, there is provided the method for preventing cultured Minori from the seaweed, wherein the nori culture net is immersed in the treatment liquid.

  The inventors of the present invention are antibacterial bacteriophages that belong to the genus Flavobacter and that can isolate pathogenic bacteria that cause Sorioli disease in laver and can prevent Sorioli disease in laver using the pathogenic bacteria. The present invention has been completed by succeeding in separation.

That was separated Flavobacterium Arthrobacter sp H. 14 Eruwai (Flavobacter sp.H14LY) as pathogenic bacteria, from Suminori Diseased leaf body generated by Saga Ariake aquaculture seaweed.

  Then, using the isolated pathogenic bacteria, the anti-smolin that can specifically infect the pathogenic bacteria from seawater or mud mud in the Ariake Sea, Saga Prefecture, and can prevent the noriminato disease caused by the pathogenic bacteria. The disease bacteriophage U2 (NITE AP-398) was isolated.

  The anti-sminori disease bacteriophage thus separated is dispersed in an appropriate liquid such as seawater to prepare a treatment liquid, and the nori culture net on which the laver is seeded is treated with the treatment liquid.

  As a treatment method, a method of immersing a nori culture net in a treatment solution can be employed. As the dipping method, the whole nori culture net may be immersed in the treatment liquid, or a part of the nori culture net is immersed in the treatment liquid sequentially from one end to the other end. Also good.

  In addition, as a processing method, in addition to immersing the nori culture net in the processing liquid, the processing liquid may be sprayed on the nori culture net in the form of a mist or a shower. However, the dipping method described above is simpler and less expensive than the above-described dipping method, and in addition, the entire area of the laver culture net can be treated uniformly without omission and is relatively long. Since the time treatment is only required once, the whole time is short, and the treatment for a relatively long time is preferable because it can be surely infected with the pathogenic bacteria of the Sumioli disease.

  Thereby, since it is possible to prevent the Sinori disease of the cultured laver without using an acid treatment agent, environmental pollution due to the acid treatment agent can be reduced. In addition, anti-sminori disease bacteriophages grow in infected pathogenic bacteria and can be released along with the rupture of pathogenic bacteria to infect other pathogenic bacteria. Later, Sminori disease prevention action increases.

  On the other hand, the anti-sminori disease bacteriophage according to the present invention is originally present in the environment, and since the bacteriophage is highly host-specific, the anti-sminori disease bacteriophage is released into the environment. However, there is no risk of adverse effects on the environment.

(Embodiment of the present invention)
First, pathogenic bacteria that cause Sorioli disease in seaweed will be described.

(Isolation of pathogenic bacteria)
A pathogenic bacterium that causes the Minori disease in the cultured seaweed was isolated as follows.
The leaflets affected by Sumiori disease that occurred in cultured seaweed in Ariake Sea, Saga Prefecture were collected, put into a sterilized mortar, and sterilized sea sand was added thereto, and the leaves were ground to obtain a ground product. After sterilized seawater was added to the ground product and mixed, a single colony was isolated by streaking several times on a plurality of modified ZoBell agar plates and culturing at 20 ° C. Each of the obtained single colonies was fished and inoculated on different modified ZoBell agar slants, and cultured at 20 ° C. to obtain a plurality of original strains. Here, a total of 20 original stocks were obtained, and identification characters A to T were attached thereto, respectively.

  In addition, after dissolving 5 g of polypeptone (Nippon Pharmaceutical Co., Ltd.) and 1 g of yeast extract (Nippon Pharmaceutical Co., Ltd.) in 1000 ml of seawater (containing about 2.4% by mass / NaCl), this solution was adjusted to pH 7.6. A modified ZoBell agar medium was prepared by adding agar (Wako Pure Chemical Industries, Ltd.) to a modified ZoBell liquid medium prepared to a concentration of 1.5 mass / volume% and sterilizing with an autoclave.

  Each original strain was subjected to the same single colony separation as before, and a plurality of strains were obtained for each of the original strains, which were used as test strains for testing whether or not they were pathogenic bacteria. Here, about 20 test strains were obtained for each of the original strains, and an identification display including an identification character indicating the original strain and an individual identification number was given to each.

Each test strain obtained in this manner was subjected to the onset test of Sminori disease as follows.
That is, a laver leaf body was collected from a laver culture net having a leaf length of 2 to 3 cm, and the leaf body was stored frozen at -20 ° C. After thawing the leaves at 5 ° C., streptomycin (Wako Pure Chemical Industries, Ltd.) was dissolved to a concentration of 300 mg / l and penicillin G potassium (Wako Pure Chemical Industries, Ltd.) to a concentration of 100 mg / l. The leaves were put into sea water and sterilized for 20 hours in an aerated state to obtain test leaves.

  After putting the test leaves into a plurality of Erlenmeyer flasks in which 100 ml of sterilized seawater was stored, one platinum ear was caught from each test strain and inoculated into each Erlenmeyer flask. This was maintained for 5 days under conditions where the temperature was 15 ° C., the illuminance was 5000 lx, and the day length was 12 hours light period / 12 hours dark period. When the cells were soaked for minutes and observed under a microscope, and the cells from which the protoplasm was discharged were present, it was determined that the leaf body had developed Minori disease.

  For each leaf body, the number of cells from which the protoplasm was discharged and the number of cells from which the protoplasm was not discharged were counted, and the percentage of cells from which the protoplasm was discharged was determined. The value concerned was the highest, and it was confirmed that the strain was highly pathogenic for Sumioli disease. This H14LY strain was used as a pathogenic bacterium.

(Bacteria identification)
The H14LY strain thus isolated was identified by 16S rDNA analysis. The H14LY strain was facultative anaerobic and was a Gram-negative bacilli (0.8 to 1.0 μm × 1.0 to 10.0 μm). Moreover, it had mobility and the form of the colony was pale yellow and glossy.

The 16S rDNA analysis was performed as follows.
That is, the pathogenic bacterium H14LY grown until the logarithmic growth phase was directly treated with phenol and chloroform to extract DNA from the bacterial body, and then the extracted DNA was precipitated and recovered by adding twice the amount of ethanol. . The DNA as a template, using two primers ^{(5'AACGAGCGMRACCC 3} 'and ^{5'GACGGGCGGTGTGTRC 3'),} were amplified 16SrDNA fragment by PCR.

  The amplified fragment was blunt-ended by treatment with Klenow DNA polymerase, cloned into pUC18 (blunt-end digested fragment) digested with HincII.

The base sequence of the 16S rDNA fragment thus cloned was determined using a primer based on the known base sequence of pUC18.
The determined base sequence was subjected to homologous search using BLASTN, and the genus and species name of the pathogenic bacterium H14LY was determined.

The base sequence obtained by analysis is shown in SEQ ID NO: 1 described later.
The strain having the base sequence shown in SEQ ID NO: 1 was found to have 99% or more homology with Flavobacter bacteria.

We have named this pathogenic bacteria and Flavobacterium Arthrobacter sp H. 14 Eruwai (Flavobacter sp.H14LY).
This Flavobacter sp. H14LY is stored in the Faculty of Agriculture, National University Corporation Saga University, and can be sold outside.

(Sminori disease onset confirmation test)
A confirmation test of the onset of Sminori disease using Flavobacter sp. H14LY isolated as described above was performed as follows.
While substituting Flavobacter sp.H14LY on the ZoBell agar slope medium described above, inoculated into a new ZoBell agar slope medium from the parental strain obtained by the latest subculture, and cultured at 20 ° C. for 48 hours. A test cell was obtained.

On the other hand, the test leaf body was prepared as described above using a laver leaf body collected from a laver culture net having a leaf length of 2 to 3 cm.
Then, 5-6 test leaf bodies were placed in a branch-shaped round flask in which 200 ml of sterilized seawater was stored, and then 6.8 × 10 ⁹ cells of the test cells were inoculated. The temperature was 15 ° C., the illuminance was 5000 lx, the day length was 12 hours light period / 12 hours dark period, kept for 120 hours (5 days) under aerated condition, and 72 hours (3 Day), 96 hours (4 days) and 120 hours (5 days) later, a part of the test leaf is obtained, the partial leaf is immersed in pure water for 20 minutes, and then under a microscope. The number of cells in which the protoplasm was discharged and the number of cells in which the protoplasm was not discharged were counted, respectively, to determine the proportion of cells in which the protoplasm was discharged.
The results are shown in Table 1 below. In addition, the result of performing the same operation as before except that the test cells are not inoculated is shown as a control.

As shown in Table 1, cells discharged from the protoplasm were observed after 3 days, and the proportion of cells discharged from the protoplasm increased as 4 and 5 days later. On the other hand, no protoplasmic discharge was observed in the control at any timing after 3 days, 4 days, and 5 days.
Next, the anti-sminoli disease bacteriophage according to the present invention will be described.

(Separation of bacteriophages)
Antisminori bacteriophages were isolated from seawater and mudflats in Ariake Sea, Saga Prefecture as follows.
That is, seawater was filtered with a sterile filter having a pore diameter of 0.22 μm, and the obtained filtrate was used as a test solution. On the other hand, about 1 g of tidal mud was suspended in 10 ml of sterilized seawater and centrifuged at 1300 × g for 10 minutes at room temperature. The supernatant was filtered with the aforementioned sterile filter, and the obtained filtrate was used as a test solution.

On the other hand, Flavobacter sp. H14LY was inoculated into an L-shaped test tube into which 10 ml of the modified ZoBell liquid medium was dispensed, and cultured with shaking at 20 ° C. overnight. 0.1 ml of the obtained culture solution is inoculated into an L-shaped test tube containing 10 ml of a new medium, and shake-cultured at 20 ° C. until the value of OD _{660 nm} becomes approximately 0.6. Got.

  Aliquots of 0.1 ml each of the test solution and the test bacterial solution obtained in this way were adjusted, the agar concentration was adjusted to 0.5 mass / volume%, and both were added to the modified ZoBell soft agar medium maintained at 40 ° C. The mixture was quickly spread on a modified ZoBell agar plate with an agar concentration adjusted to 1.5 mass / volume% so as to have a uniform thickness and overlaid.

A plurality of such double agar plates were prepared for each test solution, and each double agar plate was cultured at 20 ° C. for 2 days to observe the presence or absence of plaque formation.
Then, bacteriophage is aseptically collected from each formed plaque using a platinum loop and inoculated into a culture solution of Flavobacter sp. H14LY cultured in a modified ZoBell liquid medium to give one anti-sminoli disease bacterio. Phages were obtained.

The inventors have named this anti-sminoli bacteriophage bacteriophage U2. The bacteriophage U2 has been separated from seawater.
This bacteriophage U2 was deposited on August 10, 2007 at the Patent Microorganism Deposit Center, National Institute of Technology and Evaluation, and has been given a receipt number (NITE AP-398).

(Nature and form of bacteriophage)
Next, the results of studying the nature and form of the bacteriophage isolated as described above will be described.
First, the results of a one-stage growth test will be described.
The bacteriophage solution was prepared as follows.

Specifically, 10 ml of the modified ZoBell liquid medium was dispensed into an L-shaped test tube, Flavobacter sp. H14LY was inoculated, and after 6 hours of shaking culture at 20 ° C., bacteriophage U2 (NITE AP− 398) was added, and the mixture was further shaken overnight at 20 ° C. This culture solution is centrifuged at 12000 × g for 5 minutes at 20 ° C. to obtain a supernatant, which is filtered through a sterile filter having a pore size of 0.22 μm, and the resulting filtrate is bacteriophage U2. Liquid.

One step proliferation test, first, after the modified ZoBell liquid medium an L-shaped test tube was dispensed 10ml min, was inoculated host serving Flavobacter Sp.H14LY, and 6 hours at 20 ° C.. 0.1 ml of the bacteriophage U2 solution described above was added to this culture solution, and left to stand for 5 minutes to infect the host with bacteriophage U2.

  Next, the culture solution is centrifuged to collect a host infected with bacteriophage U2, and the obtained cells are suspended in a sterilized 100 mM phosphate buffer (PBS) (pH 7.0). The washing operation for collecting the cells again by centrifugation was repeated twice.

Each bacterial cell obtained by washing and removing the remaining bacteriophage in this way is suspended separately in a new modified ZoBell liquid medium so as to be approximately 1 × 10 ⁴ cells / ml, and statically incubated at 20 ° C. Incubated.

  A predetermined amount of sample was taken from each culture medium at an appropriate time, and each sample was treated with chloroform to stop the growth of host bacteria. Thereafter, 0.1 ml of each sample is added to the modified ZoBell soft agar medium and mixed with 0.1 ml of the above-mentioned test bacterial solution, and a double agar plate is prepared in the same manner as before and cultured at 20 ° C. to form. Plaques were counted.

  FIG. 2 is a graph showing the results of a one-stage growth test for bacteriophage U2, where the vertical axis represents the number of plaques formed logarithmically and the horizontal axis represents the time at which the sample was collected. In addition, the timing which suspended the microbial cell obtained by wash | cleaning a bacteriophage in the new culture medium was set to 0 hour.

As shown in FIG. 2, the one-stage growth curve has a sigmoid shape, and the time from the infection to the host until the release is completed (latency period + release period) was approximately 60 minutes.
The burst size, which is the number of phage released per host cell, was approximately 40.
From these results, it was confirmed that bacteriophage U2 is a virulent phage.
In addition, the formed plaque had a relatively large diameter of 6 to 9 mm as shown in the micrograph in FIG. .

Next, the results of examining the cleavage pattern of the gene extracted from bacteriophage U2 will be described.
After adding phenol to the bacteriophage U2 solution prepared by the same operation as above and extracting the aqueous bacteriophage U2 gene by separating the aqueous layer, ethanol is added to the separated aqueous layer. The extracted gene was precipitated by allowing to stand at a temperature of −20 ° C.

  Each of the genes precipitated by centrifuging this liquid and discarding the supernatant was obtained, each obtained gene was washed with ethanol, dried under reduced pressure, and then an appropriate amount of 50 mM Tris-EDTA buffer ( It was dissolved in pH 7.0) to obtain a test gene solution of bacteriophage U2.

  After adding 2.0 units of restriction enzyme HindIII (Nippon Gene Co., Ltd.) to 10 μl of each test gene solution prepared as described above and maintaining at 37 ° C. for about 1 hour, each gene was cleaved at a specific site, and then a sample solution was prepared. This was subjected to electrophoresis on 0.7% agarose gel (Nippon Gene Co., Ltd.).

  FIG. 4 is a photograph showing the results of agarose gel electrophoresis. M is a DNA obtained by cleaving DNA of λ phage as a molecular weight marker with HindIII, and the numerical value of the molecular weight of each fragment is shown on the left side. The unit of molecular weight is kbp.

  Thus, the gene extracted from bacteriophage U2 was cleaved by restriction enzyme HindIII that recognizes a specific site of DNA, and thus it was confirmed that the gene of bacteriophage U2 was DNA.

Next, the results of examining the infectivity stability of the anti-sminoli disease bacteriophage according to the present invention will be described.
FIG. 5 is a graph showing the results of examining the infectivity stability of bacteriophage U2, wherein the vertical axis indicates infectivity and the horizontal axis indicates the retention period.

The bacteriophage U2 solution prepared as described above is held at 4 ° C. for 70 days, a part of the sample solution is collected every 14 days from the start of the holding, and the number of plaque formation per ml of the sample solution is detected to determine the infectivity. did. In addition, Flavobacter sp.H14LY was used as a host bacterium for plaque formation, and a modified ZoBell medium was used as a medium.
As is apparent from FIG. 5, the infectivity of bacteriophage U2 was 90% or more of the initial infectivity even after 70 days had elapsed, and the infectivity stability was high.

(Anti-Sminori disease action)
Next, the result of having tested the anti-sminori disease action which prevents the minori disease of cultured seaweed using bacteriophage U2 is demonstrated.
Preparation of the test leaves, test cells and bacteriophage U2 solution was carried out in the same manner as before.

After putting 5 or 6 test leaves into a round flask with branches in which 200 ml of sterilized seawater is stored, about 1 × 10 ⁹ cells in the infected and phage-treated areas Was inoculated. In the control group, the test cells and bacteriophage U2 described later are not inoculated.
In the phage-treated group, bacteriophage U2 solution was added so as to be about 1 × 10 ⁸ pfu after 5 minutes had passed after inoculation of the test cells.

And, after holding for 7 days under the condition that the temperature is 15 ° C., the illuminance is 3000 lx, the day length is 12 hours light period / 12 hours dark period, and the ventilation state is obtained, the test leaves are obtained respectively. Then, after immersing them in pure water for 20 minutes, it was observed under a microscope whether or not the protoplasm was discharged.
As a result, the protoplasm was discharged from about 30% of the cells in the infected group, but the protoplasm was only discharged from about 5% of the cells in the control group and the phage-treated group.
Therefore, it was confirmed that bacteriophage U2 has an anti-sminori disease action.

In the control group and the phage-treated group, a small number of cells ejected from the protoplasm are present because relatively young cells with thin cell walls cannot withstand osmotic shock due to exposure to pure water. This is probably because
Some of the microscopic observation results in the control group, the infected group and the phage-treated group are shown in FIGS.

  FIG. 6 is a micrograph of the leaf body in the control group, FIG. 7 is a micrograph of the leaf body in the infected group, and FIG. 8 is a micrograph of the leaf body in the phage-treated group.

As apparent from FIG. 7, in the leaves of the infected area, the protoplasm was discharged, while pure water invaded and many cells having a relatively large size were observed.
On the other hand, as is clear from FIGS. 6 and 8, such relatively large cells were hardly observed in the leaves of the control group and the phage-treated group.

Next, a method for preventing the Sinori disease of cultured seaweed using the anti-Sminoori disease bacteriophage according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partially broken perspective view showing one embodiment of the method for preventing a Minori disease according to the present invention, in which 1 is a treatment tank and 10 is a laver culture net. The treatment tank 1 may have a volume capable of storing an appropriate number of folded laver culture nets 10, 10,..., And any hard material or soft material can be used as long as the material can hold a liquid. There may be.

For example, when a container having a bottom area of 1 m ² and a capacity of 200 l is used, 10 to 15 laver culture nets 10 can be processed. On the other hand, when the wall part of the processing tank 1 is made into a sheet shape, the processing tank 1 can be carried in a reduced state, and the carrying work of the processing tank 1 can be facilitated.

In the example shown in FIG. 1, the processing tank 1 is configured by fixing a waterproof sheet member to a metal frame member.
The peripheral wall of the processing tank 1 is a dark color, and can absorb sunlight and raise the temperature in the processing tank 1. Further, the opening of the processing tank 1 is detachably blocked by a dark-colored lid member 2, and the opening of the processing tank 1 is blocked by the lid member 2, so that the processing tank 1 can be opened from the inside of the processing tank 1. Heat dissipation to the outside can be suppressed and the temperature in the processing tank 1 can be further increased.

Accordingly, the processing liquid stored in the processing tank 1 is kept at a required temperature of about 20 ° C. without using another heat source even in the autumn to winter season, which is the main season for processing the nori culture net. The temperature can be raised.
Using such a treatment tank 1, the laver culture nets 10, 10,... Are treated as follows.

  After the processing liquid W such as seawater is poured into the processing tank 1 so that the nori culture nets 10, 10,... Are immersed, the opening of the processing tank 1 is blocked by the lid member 2 and the sunlight is absorbed. The temperature of the processing liquid W in the processing tank 1 is increased to about 5 ° C to 20 ° C.

  As the treatment liquid W described above, seawater can be used, but a liquid having a required salt concentration such as a solution in which NaCl is dissolved in fresh water so as to be 1 to 3 mass / volume% can be used. Furthermore, other inorganic components such as magnesium chloride may be added.

On the other hand, the anti-sminori disease bacteriophage solution B is prepared. That is, a culture solution containing bacteriophage U2 is added to a culture solution obtained by culturing Flavobacter sp. H14LY in a modified ZoBell liquid medium, and further cultured. Then, the culture solution is centrifuged to obtain a supernatant, and the supernatant is filtered with a sterile filter having a pore size of 0.22 μm.

  In addition to the ZoBell medium, a medium containing an appropriate concentration of salt, peptide, vitamins, etc., such as marine groth2216E medium (Wako Pure Chemical Industries, Ltd.) can be used. Further, as described above, an appropriate amount of antibiotics may be aseptically added to the filtrate obtained by using a sterile filter. Furthermore, an operation of concentrating phages by high-speed centrifugation using the filtrate may be performed.

The anti-sminori disease bacteriophage solution B adjusted in this way is added to the processing solution W in the processing tank 1 so as to be on the order of 1 × 10 ⁵ pfu to 1 × 10 ⁸ pfu, and seeded. The frozen seaweed cultivation nets 10, 10,... That are stored frozen at approximately −20 ° C. are immersed in the processing solution W in the processing tank 1 as they are or after thawing.

In addition, when using the seeded nori culture net | network 10 without cryopreserving, the seedling nori culture net | network 10 is immersed in the process liquid W in the processing tank 1 as it is.
Then, the laver culture nets 10, 10,... Treated with the anti-sminori disease bacteriophage in this way are directly or after being washed with seawater, displayed on the farm.
Here, since the bacteriophage has high host specificity as described above, the anti-sminori bacteriophage does not infect cultured laver.

  In the present embodiment, all of the laver culture nets 10, 10,... Are immersed in the treatment liquid W of the treatment tank 1, but the present invention is not limited to this, and the laver culture nets. A part thereof may be sequentially immersed in the processing liquid W from one end to the other end of 10.

In addition to immersing the nori culture net 10 in the processing liquid W, the processing liquid W may be sprayed on the nori culture net 10 in a mist or shower form.
However, the dipping method described above is simpler and less expensive than the above-described dipping method, and in addition, the entire area of the laver culture net can be treated uniformly without omission and is relatively long. Since the time treatment is only required once, the whole time is short, and the treatment for a relatively long time is preferable because it can be surely infected with the pathogenic bacteria of the Sumioli disease.

In the above-described embodiment, the present invention, which belongs to the genus Flavobacter, specifically infects nori pathogenic bacteria that cause sminori disease in the laver, and prevents the onset of sorioli disease in laver caused by the pathogenic bacteria The present invention also provides an anti-sminoli disease agent comprising an anti-sminori disease bacteriophage that can be treated as an active ingredient.
As described above, the bacteriophage used in this anti-sminoli disease agent is bacteriophage U2.
The aforementioned pathogenic bacterium is Flavobacter sp. H14LY.

It is a partially broken perspective view which shows one Embodiment of the Sminori disease prevention method which concerns on this invention. It is a graph which shows the result of having performed the one-stage growth test about bacteriophage U2. It is a microscope picture figure of the plaque formed by bacteriophage U2. It is a photograph figure which shows the result of having performed agarose gel electrophoresis. It is a graph which shows the result of having test | inspected the infectivity stability of bacteriophage U2. It is a microscope picture figure of the leaf body in a control group. It is a microscope picture figure of the leaf body in an infected area. It is a microscope picture figure of the leaf body in a phage processing section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing tank 2 Lid member 10 Nori culture net W Processing liquid B Anti-sminori disease bacteriophage liquid

Claims (3)

Infects Flavobacter sp.H14LY, a pathogenic bacterium that belongs to Flavobacter genus and causes pathogenic bacteria in nori seaweed, and prevents Sorioli disease of laver caused by the pathogenic bacteria Bacteriophage U2 (NITE AP-398) . The anti-sminori disease bacteriophage according to claim 1 is suspended in an appropriate liquid to prepare a treatment liquid, and a nori culture net on which nori seeding has been carried out is treated with the treatment liquid. A method for preventing Sumiori disease in cultured seaweed. The method for preventing a smoldering disease of cultured seaweed according to claim 2, wherein the seaweed culture net is immersed in the treatment liquid.