JPH062649B2 - Antifungal agent - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antifungal agent against filamentous fungi, particularly plant pathogens such as Fusarium spp. And Botrytis spp. More specifically, the present invention relates to an antifungal agent containing an α-1,4-linked polygalactosamine as an active ingredient.

The antifungal agent of the present invention is capable of inhibiting the growth of phytopathogenic fungi by addition or spraying to soil or plants, for example, Fusarium sp., Which is a phytopathogenic fungus, very effectively as a Botrytis sp. Available.

(Prior art and problems) Conventional antifungal agents include copper preparations represented by Bordeaux's solution, heterocyclic compounds used for powdery mildew, imidazole agents used for scab, etc. Are known. However, in recent years, in addition to acute toxicity, chronic toxicity, carcinogenicity, genotoxicity, etc.
A more safe antifungal agent is required.

Reflecting these facts, research has been conducted on natural pectin degradation products, protamine, spices and chitin, chitosan or its mild degradation products, which are components of shrimp and crab shells, and partially commercialized. Is being considered.

α-1,4 polygalactosamine is also a natural polysaccharide produced by microorganisms and is structurally similar to chitosan having glucosamine as a constituent sugar, and is expected to have similar physiological activities.

However, polygalactosamine (α-1,4 galactosaminogalactan) is extremely rare in the natural world, and PF-101 and PF-102 derived from imperfect bacteria are known (Japanese Patent Publication No. 56-1239). JP-A-62-294093).

Further, it is generally known that the physicochemical properties of a polysaccharide change due to its low molecular weight, which makes it easier to handle than the state of a polymer, and has remarkable physiological activity. Also in this polygalactosamine, not only the method of treating it with an acid or an alkali as a method for lowering the molecular weight but also the method by enzymatic decomposition, that is, the polygalactosamine-degrading enzyme produced by Pseudomonas sp. (Kaisho 63-164884, JP 63-164885).

(Means for Solving Problems) An object of the present invention is to provide a more safe antifungal agent.

The present invention relates to an antifungal agent containing α-1,4-linked galactosamine as an active ingredient. The α-1,4-bonded galactosamine, which is an active ingredient of the antifungal agent in the present invention, is an imperfect bacterium, P. esculomyces I-1 (Microtechnology Research Institute, 1180 FERM BP-118.
It can be obtained as PF-101 and PF-102 by cultivating 0). In addition, by hydrolyzing PF-101 and PF-102 with a polygalactosamine-degrading enzyme produced by Pseudomonas sp H881 (Microtechnology Research Institute, No. 8955), or
By degrading the degradation products obtained by acid hydrolysis with an ultrafiltration membrane, respectively, a poly (α-1,4) -bonded polymer having a molecular weight cutoff of 50,000 or more, 10,000 or more and less than 50,000 and less than 10,000 is obtained. It can be obtained as galactosamine.

As the antifungal agent of the present invention, α-1,4-bonded galactosamine such as PF-101, PF-102, degradation products and fractions thereof can all be used alone or in combination.

Next, the bacteria producing α-1,4 polygalactosamine, PF-101 and PF-102 will be described.

The incomplete bacterium I-1 isolated from the humus layer in Wakayama Prefecture is recognized as belonging to the genus Paecilomyces,
The strain was named P. esculomyces I-1, and the strain was designated as FER
Deposited as M BP-1180.

Next, the mycological properties of Paecilomyces I-1 are shown.

[A] Observation under a microscope This fungus lacks a conidiophore, and conidia are long at the tip of each independent phialide that grows directly from vegetative hyphae or bundles of vegetative hyphae. Derived in a chain. Phialides are translucent and have a length of 20-45μ, a slightly thicker base (1.0-1.5μ), a slightly tapered tip (0.5-1.0μ), and some with straight or slightly curved tips. Conidia are of cigar-tobacco type (or bacillus type) by electron microscope, and their size is 4-6.
× 1.0 to 1.4μ.

Conidia are usually 25-35 linked, but in some rare cases, longer chains are observed. The chain of conidia is very brittle and easily breaks down with a slight shock.

[B] Growth state in each medium (25 ° C. plane culture) (1) Tuapec agar medium The colonies grow well and reach a diameter of about 45 mm on the 14th day. White velvety to wooly flora with tufted ridges in the center and a round colony. No water drops or wrinkles. The back of the colony is white in the early stage of culture and pale yellow in the middle of the latter stage of culture. No pigment production in agar is observed.

(2) Malt agar medium The growth of colonies is good, and the diameter of the colonies is about 54 mm on the 14th day.

The central part of the flora is white, but the peripheral part is pale yellow. The flora is moderately thick and the center is slightly concave. Water drop
No wrinkles were observed, and the entire back surface of the colony was pale yellow. Production of pale yellow pigment on agar medium.

(3) Potato dextrose agar medium The colonies grow very well and reach a diameter of about 60 mm on the 14th day. White velvety or wooly thick flora is formed, the central part is slightly swelling, the sub-central part is pale yellow with a slightly thin flora, and the peripheral part is a white relatively thick flora. . There are no wrinkles on the surface, but some light brown water droplets are observed. There are several radial wrinkles on the back of the colony,
Concentric yellow shades are observed. There is diffusion of a pale yellow pigment into the agar.

(4) YpSs agar medium (composition starch 1.5%, ace extract)
0.4%, K ₂ HPO ₄ 0.1%, MgSO ₄ 0.05%, agar 2%) The colonies grow well and reach a diameter of about 50 mm on the 14th day.
It is a white, fluffy, thick, flora of flora.
No water drops or wrinkles. There are no special features on the back of the colony.
No pigment production.

(5) MY ₂₀ agar medium (composition glucose 20%, polypeptone
0.5%, yeast extract 0.3%, malt extract 0.3%, agar 2%) The growth of colonies is not so good, and the diameter is about 30 mm on the 14th day. The aerial mycelium does not fold so much and there are many fine wrinkles. The peripheral part is pale yellow and the central part is pale brown. The back side of the colony is pale yellow with fine wrinkles. No pigment production.

Peesiromyces I-1 can be cultivated by an ordinary liquid culture method for filamentous fungi.

The spores or hyphae of P. cerevisiae I-1 are inoculated into a liquid medium and aerobically cultured. As the carbon source, glucose, maltose, sucrose, starch, molasses and the like can be used, but glucose is preferably used. As the nitrogen source, inorganic nitrogen such as ammonium sulfate and sodium nitrate, and organic nitrogen such as peptone and yeast extract can be used.

The culturing temperature may be appropriately changed within a range in which the present flocculant-active substance-producing bacterium produces the flocculant-active substance, but it is usually preferable to culture at 20 to 25 ° C. The culturing time varies depending on the culturing conditions, but is usually about 4 to 5 days, and it may be completed at an appropriate time by estimating the time when the aggregation-active substance reaches the maximum. Here, if the culture filtrate is concentrated by a method such as vacuum concentration or ultrafiltration and an organic solvent such as ethanol is added as a concentrate to cause precipitation, PF-101 described in JP-B-56-12639 can be obtained. is there.

In addition, PF-101-producing bacterium, Pseudomyces I-1, was cultivated, filtered, various salts were added to the obtained culture filtrate or filtrate concentrate, and if precipitation did not occur, alkali was added if necessary. Precipitation is carried out by adjusting the pH to 7 to 9, and the precipitate is separated, washed with water, dissolved in a dilute aqueous acid solution, and salt is added again or the pH is adjusted to 7 to 9 by adding an alkali or the like to precipitate. , PF-10 described in JP-A-62-294093
You can get 2.

The physicochemical properties of PF-101 are as follows.

(1) Aggregation activity: Aggregates suspended fine particles with an extremely small amount.

(2) Aggregation activity pH range: Stable aggregation activity is exhibited at pH 2-9.

(3) Aggregation activity temperature range; aggregation activity is recognized at 0 to 100 ° C.

(4) Aggregation active ionic strength; carbonate ion and Fe ₂ (SO ₄ ) ₃
Agglutination activity is inhibited by, but agglutination activity is not affected by other various ions and ionic strength, and NaCl, K ₂ S
O ₄ has no effect up to 1M.

(5) Elemental analysis; nitrogen 5.44%, carbon 37.45%, hydrogen 6.3%,
Phosphorus 0.27%.

(6) Ultraviolet absorption spectrum; as shown in FIG.

(7) Infrared absorption spectrum; as shown in FIG.

(8) Color reaction; Ninhydrin reaction-Xanthoprotein reaction-Erich reaction-Morish reaction + Phenol-sulfuric acid reaction + Relzen test- (9) Hydrolysis with acid; 6N hydrochloric acid, 110 ° C, and galactosamine by decomposition for 20 hours Ammonia is obtained, 4N hydrochloric acid, 10
Decomposition at 0 ° C for 16 hours gives a small amount of ammonia, which is 74% of the standard, galactosamine.

(10) Electrophoresis; confirmed as a single substance by density gradient isoelectric focusing, with an isoelectric point (pI) of 8.5.

(11) Color of substance; pale yellowish white (12) Basic, acidic, neutral; slightly basic at isoelectric point 8.5. (The pH of 0.1% aqueous solution is 6.2, the pH of deionized water is
5.8) (13) Solubility in solvent; ・ Soluble in hot water, and does not precipitate even if dissolved and cooled.

・ Slightly insoluble in cold water.

-Slightly soluble in dilute acid and dilute alkali.

・ Alcohols, acetone, chloroform, benzene,
Insoluble in ethyl acetate and n-pentane.

The physicochemical properties of PF-102 are as follows.

(1) Aggregation activity: Aggregates suspended fine particles with an extremely small amount.

(2) Aggregation activity pH range: Stable aggregation activity is exhibited at pH 2-9.

(3) Aggregation activity temperature range; aggregation activity is recognized at 0 to 100 ° C.

(4) Aggregation activity Ionic strength: Aggregation activity is inhibited by carbonic acid and Fe ₂ (SO ₄ ) _3, but the aggregation activity is not affected by various other ions and ionic strength, and 1M with NaCl and K ₂ SO ₄ .
Does not affect at all.

(5) Elemental analysis; nitrogen 8.64% &, carbon 42.80%, hydrogen 6.87
% General formula: (C ₆ H ₁₁ NO ₄ · xH ₂ O) n (6) Ultraviolet absorption spectrum; as shown in FIG. 3.

(7) Infrared absorption spectrum; as shown in FIG.

(8) Color reaction; Ninhydrin reaction + Xanthoprotein reaction-Erich reaction-Morish reaction-Phenol-sulfuric acid method ± Rerosen test- (9) Electrophoresis; Confirmed as a single substance by density gradient isoelectric focusing , The isoelectric point (pI) is 8.5.

(10) Color of substance; pale yellow (11) Distinction of basic, acidic, and neutral pH when suspended in water at 0.5% w / v is 7.5 (p
H5.8).

(12) Solubility in solvent ・ Insoluble in hot water ・ Insoluble in cold water ・ Easy in dilute acid ・ Insoluble in dilute alkali ・ Alcohols, acetone, chloroform, benzene,
Insoluble in n-pentane.

(13) Average molecular weight 160,000 or more The above PF-101 and PF-102 were both identified as α-1,4 polygalactosamine, and antibacterial properties were observed in the present invention. The antibacterial property was also recognized in the fractionated products, and the present invention was completed.

When the α-1,4 polygalactosamine is decomposed, that is, when the molecular weight is reduced, hydrolysis with an acid such as hydrochloric acid or sulfuric acid or hydrolysis with a polygalactosamine-degrading enzyme is performed.

Next, one example of the polygalactosamine degrading enzyme will be described.
This polygalactosamine degrading enzyme is Pseudomonas sp H
It is produced by the 881 FERM P-8955.

(1) Action and Substrate Specificity The present enzyme acts on oligo and polygalactosamine (α-1,4 polygalactosamine) having a degree of polymerization of n = 4 (tetra-galactosamine) or more to produce oligogalactosamine.

Other polysaccharides, starch (α-1,4 glucan), glycogen (α-1,4 glucan), pullulan (α-1,4 glucan),
Dextran (α-1,6 glucan), Laminaran (β-1,3
Glucan), carboxyl cellulose (β-1,4-glucan), chitosan (β-1,4 glucosaminoglucan), ethylene glycol chitin (β-1,4N-acetylglucosaminoglucan), Pseudomonas solanacearum poly N -Acetylgalactosaminogalactan (poly β-1,3N-acetylgalactosaminogalactan) (Y. Akiyama., Et.al., Agric. Biol. Chem., 50
(3) 747, 1986) etc. does not work at all.

Further, the degree of polymerization n = 3 (tri-galactosamine) or less α
It has no effect on -1,4-galactosamino oligosaccharides.

(2) Optimum pH and stable pH range When citrate phosphate buffer is used, the optimum pH is 4.5-7.0.
Is. The stable pH range is pH 4.5 to 8.0. In this measurement, the residual activity of the enzyme left at 37 ° C. for 1 hour was shown as a relative value.

(3) Method for measuring enzyme activity Oxygen activity is PF-101 produced by Paecilomyces I-1 as a substrate
Alternatively, PF-102 (the main constituent sugar thereof is α-1,4 galactosaminogalactan) was used. This 0.5% / 0.1 molar acetate buffer pH 6.0
An enzyme solution (0.5 ml) was added to the solution (0.5 ml), the mixture was reacted at 37 ° C. for 10 minutes, and the resulting reducing power was measured by the Somogyi-Nelson method. The enzyme unit was defined as 1 unit of activity for increasing the reducing power corresponding to 1 μmol of galactosamine per minute.

(4) Optimum temperature of action and temperature stability range The optimum temperature of this enzyme is 55 ° C, and it drops sharply above that temperature. 70% of the activity remains at 50 ° C for 1 hour.

A decomposed product of α-1,4 polygalactosamine can be obtained by adding a polygalactosamine degrading enzyme to a solution of α-1,4 polygalactosamine and enzymatically decomposing at about 35 to 40 ° C.

Since the anti-mildew is found in the decomposed product of α-1,4 polygalactosamine, it can be used as it is as an antifungal agent, but the decomposed product of α-1,4 polygalactosamine is separated by an ultrafiltration membrane or the like. Fractionation into various molecular weight units can be obtained by drawing.

The decomposed product of α-1,4 polygalactosamine can be obtained by an ultrafiltration membrane as a fractionated product having a molecular weight of 50,000 or more, a molecular weight of 10,000 or more and less than 50,000, and a molecular weight of less than 10,000. The product also has antibacterial properties and serves as the antifungal agent of the present invention.

The present invention is an antifungal agent containing α-1,4 polygalactosamine, a degradation product thereof or a fractionated product thereof as an active ingredient.

In the present invention, the active ingredient is used as an additive as it is, or is formulated into various liquids and powders and used effectively as an antifungal agent.

Next, production examples and examples of the present invention will be shown.

Production Example 1 Production of α-1,4 polygalactosamine (PF-102) Glucose 600 g, polypeptone 60 g, CaCl ₂ .2H ₂ O125
g was dissolved in tap water 17, adjusted to pH 7.0 with concentrated NaON solution, and transferred to a 30-volume jar fermenter.

By injecting steam into this medium solution, pressurization and heat sterilization (121 ° C., 20 minutes) were performed. To the cooled medium (final volume 20), 150 ml medium of the same composition in a 500 ml Erlenmeyer flask (glucose 3%, polypeptone 0.3%, CaCl ₂ 0.5%, p
(H7.0) cultured at 26 ° C for 4 days with shaking Pesylomyces I-
1. FERM BP-1180 (FERM P-3928) was inoculated aseptically at a volume ratio of about 10%. 27 ℃ after inoculation, aeration rate 0.5 VVM, agitation number 200 RPM
The cells were cultured under the conditions of 5 days.

After the completion of the culture, the culture filtrate is filtered by filtering the culture with a filter cloth.
Got The low molecular weight fraction was removed by passing this culture filtrate through an ultrafiltration membrane (UF membrane tubular module F type manufactured by Mitsubishi Rayon Engineering Co., Ltd.) having a molecular weight cutoff of 160,000 while heating at 50 ° C to 60 ° C. It concentrated until the liquid volume became about 3. Further, the cell residue and the heat-organized protein were removed by centrifugation at about 14000 × G.

After centrifugation, about 750 g (about 25% concentration) of sodium chloride was added to the supernatant fraction 3 and stirred. After dissolution, the pH was adjusted to 7.0 to 8.5 with concentrated NaOH. After allowing to stand overnight to sufficiently deposit the salted out product, the salted out product was recovered on a cloth made of Saran (vinylidene chloride and vinyl chloride copolymer). Further, a large amount of slightly alkaline water (pH 7.0 or more) was removed from the salted-out product to wash away excess salt and neutral sugars and other contaminants simultaneously mixed in the culture solution.

Next, the salted out product after washing with water was dissolved by adding a 0.1 M hydrochloric acid solution in an amount of about 3 times by volume. A concentrated NaOH solution was added to this lysate to adjust the isoelectric point of polygalactosamine to pH 8.5. After allowing to stand overnight to sufficiently deposit a precipitate, the precipitate was collected on a Saran cloth as in the case of air and washed with a large amount of tap water. This washed product was again dissolved in 0.1M hydrochloric acid, and then subjected to isoelectric point precipitation and repeated washing with water for purification.

The purified precipitate was sterilized at 121 ° C for 15 minutes and then lyophilized to obtain PF containing polygalactosamine as a main component.
7 g of a purified powder of -102 (purity of α-1,4 polygalactosamine of about 99%) was obtained.

Production Example 2 Fractionation Method of α-1,4 Polygalactosamine 100 g of purified α-1,4 polygalactosamine (PF-102) was dispersed in 4N hydrochloric acid 2 and placed in an Erlenmeyer flask equipped with a cooling tube.
Hydrochloric acid was hydrolyzed at 80 ° C. for 4 hours.

After decomposition, this hydrochloric acid hydrolyzed solution was neutralized with 10N sodium hydroxide to pH 7. First, this solution is cut to a molecular weight cutoff of 5
Treatment with an ultrafiltration membrane of 10,000 (manufactured by Grace Japan) and further treatment with an ultrafiltration membrane having a molecular weight cutoff of 10,000. In this way, α-1,4 having a molecular weight of 50,000 or more, 1 to 50,000 and less than 10,000, respectively.
Bound polygalactosamine was obtained.

A powder sample was obtained by freeze-drying each fraction.

Production Example 3 Production of Polygalactosamine Degrading Enzyme Pseudomonas sp H881 and FERM P-8955 were inoculated in a 500 ml Erlenmeyer flask into 100 ml of a seed medium having a composition of 0.5% glucose, 0.05% yeast extract and 0.05% polypeptone, and 30
Incubate at ℃ for 20 hours.

The resulting seed culture in 30 jar fermenters,
Polygalactosamine (PF-102) 0.25%, glucose 0.25
%, Yeast extract 0.05%, polypeptone 0.05%, inoculated into the enzyme production medium 18, and aerated (18 / min) at 30 ° C for 48 hours.
Incubate (200 rpm).

The obtained culture solution was centrifuged (14000 rpm) to remove bacterial cells, and the obtained culture filtrate (enzyme activity 0.0035 U / ml, total activity 63
Add cooled ethanol to U / 18) to 60% concentration,
The protein is precipitated and the precipitated protein is centrifuged and separated from the solution. The obtained protein was equilibrated with 0.1 molar acetate buffer (pH 5.0), CM-Sephadex C-25.
Adsorb to a column (2.5 × 60 cm) and elute with the same buffer having a concentration gradient of 0 to 0.5 molar sodium chloride.

Collect the eluted enzyme activity fractions and use an ultrafiltration device (molecular weight 1
10,000 hold) to concentrate. Next, 0.2 mol containing sodium chloride.
A 1 molar acetic acid buffer solution (pH 6.0) is prepared and subjected to Sephadex G-50 column (5 × 90 cm) chromatography equilibrated with the same buffer solution. Then, the salt concentration of the active section was increased to 4 mol, and the column was adsorbed on a phenyl-Sepharose CL-4B column (2.5 × 20 cm) equilibrated with the same solution, and the column was treated with 0.1 mol acetate buffer having a reverse salt concentration gradient. Eluted and purified polygalactosamine degrading enzyme 50 mg (yield 23.1%, specific activity 52 μg
galN / min / mg protein) was obtained.

Production Example 4 Fractionation method of α-1,4 polygalactosamine 25 g of purified polygalactosamine was dissolved in 0.1 mol acetic acid of 4.8, and then adjusted to pH 6.0 with sodium hydroxide to give a total solution of 5. Using this polygalactosamine solution as a substrate, 10 mg of the purified polygalactosamine-degrading enzyme obtained in Production Example 3 was added, and the enzyme was decomposed at 37 ° C. The solution after the decomposition was first treated with an ultrafiltration membrane having a molecular weight cutoff of 50,000 (manufactured by Grace Japan) and further treated with an ultrafiltration membrane having a molecular weight cutoff of 10,000. In this way, molecular weights of 50,000 or more and 1-5
Tens of thousands and less than 10,000 α-1,4 linked polygalactosamines were obtained.

Further, each fraction was freeze-dried to obtain a powder sample.

The physicochemical properties of the α-1,4-bonded polygalactosamine having a molecular weight cut off of 50,000 or more are as follows.

1 Elemental analysis; Nitrogen 8.6%, Carbon 42.8%, Hydrogen 6.9%, Oxygen 41.7% 2 Specific optical rotation; ▲ [α] ²⁰ _D ▼ ＝ + 215-225 3 Melting point; Browning at 160 ℃ or higher, Carbonization at 210 ℃, 230 Ash at 4 ℃ Color of 4 substances; Light yellow 5 Color reaction; Ninhydrin reaction + Xanthoprotein reaction-Erich reaction-Morish reaction-Phenol sulfuric acid reaction ± 6 Solubility in solvent; -Slightly soluble in water-In dilute acid Soluble-Slightly soluble in methanol, ethanol, acetone, chloroform, and hexane 7. Ultraviolet absorption spectrum; shown in FIG.

8 Red external absorption spectrum; shown in FIG.

The physicochemical properties of α-1,4-bonded polygalactosamine having a molecular weight cutoff of 10,000 or more and less than 50,000 are as follows.

1 Elemental analysis; Nitrogen 8.7%, Carbon 45.7%, Hydrogen 3.2%, Oxygen 42.4% 2 Specific optical rotation; ▲ [α] ²⁰ _D ▼ = + 210 to 220 3 Melting point; No specific melting point, browning at 160 ° C Carbonization at 210 ℃, Ashing at 230 ℃ Color of 4 substances; Light yellow 5 Color reaction; Ninhydrin reaction + Xanthoprotein reaction-Erich reaction-Morish reaction-Phenol-sulfuric acid method ± 6 Solubility in solvent; Soluble-Slightly soluble in methanol-Slightly soluble in dimethyl sulfoxide-Slightly soluble in ethanol, acetone, chloroform, hexane 7 Ultraviolet absorption spectrum; shown in FIG.

8 Red external absorption spectrum; shown in FIG.

The physicochemical properties of α-1,4-bonded polygalactosamine having a molecular weight cut-off of less than 10,000 are as follows.

1 Elemental analysis; Nitrogen 8.6%, Carbon 44.7%, Hydrogen 3.9%, Oxygen 40.2% 2 Specific optical rotation; ▲ [α] ²⁰ _D ▼: +206.8 3 Melting point; Carbon having no specific melting point and above 160 ° C To start.

4 Color of substance; pale yellow 5 Color reaction; Ninhydrin reaction + Indole hydrochloric acid reaction + Somogy-Nelson reaction + Phenol sulfuric acid reaction-Iodine reaction-6 Solubility in solvent; -Soluble in water-Soluble in dilute acid-Methanol・ Slightly soluble in dimethyl sulfoxide ・ Slightly soluble in ethanol, acetone, and chloroform 7 UV absorption spectrum; shown in FIG.

8 Red external absorption spectrum; shown in FIG.

Example 1 α-1,4 polygalactosamine (PF-10) produced in Production Example 1
2), a hydrochloric acid decomposition product of α-1,4 polygalactosamine produced in Production Example 2 and a fractionated product of the hydrochloric acid decomposition product prepared in Production Example 2 each having a molecular weight of α-1,4 polygalactosamine 30 g of potato dextrose medium (potato dextrose agar medium: Eiken Kagaku Co., Ltd.) was dissolved in 1000 ml of purified water by heating, and then added so as to be 0.1% at 121 ° C. and 15 ° C., respectively.
After a minute autoclave, an agar plate medium was prepared.

On the plate medium containing polygalactosamine of each molecular weight, 1 platinum loop was inoculated from a pre-cultured mold slant and cultured at 27 ° C. for 4 days, and then the diameter of the colony was measured.
The antibacterial activity was shown by the ratio of colonies in each test group when the diameter of the mold colonies inoculated on the medium without polygalactosamine was 100.

The molds tested were Aiternaria kikuchiana IFO 8414, Botrytis cinerea, Cochibolus miyabeanus IFO 5277, Diaporthe citri IFO 9170, Elsinoe fawcetti IFO 8417, Fusarium oxysporum capae, Fusarium solni, Gibberella zeae IFO 7888, Iria 7ris, Guiaberia irregulare IFO 527
3, Pestalotia funerea, Piricularia oryzae IFO 5279, Sclerotinia scleotiorum IFO 9395, Venturia prina IFO 6189.

The results are as shown in Table 1.

Example 2 The fractionated molecular weight of less than 10,000 obtained in Production Example 2 was further fractionated to obtain a galactosamino oligo-6 sugar. The properties of galactosamino oligo-6 sugar are as follows.

1) Hexasaccharide of galactosamine consisting only of α1 → 4 bonds GalN ₁ → ₄ GalN ₁ → ₄ GalN ₁ → ₄ GalN ₁ → ₄ GalN ₁ → ₄ GalN (where GalN is α-D-galactopyranosyl group 2) Color and shape: pale yellow amorphous powder.

3) Taste: It has a weak sweetness.

4) Solubility: Soluble in dilute acid, salt solution and water. Insoluble in common organic solvents except dimethyl sulfoxide.

5) The following elemental analysis values are shown.

C: 43.90, H: 6.91, N: 8.54, O: 40.65 Expected molecular formula: C ₃₆ H ₆₈ O ₂₅ N ₆ 6) The molecular weight and structural formula are as follows.

Molecular weight: 984.6 7) Color reaction: Positive for indole hydrochloric acid reaction, Elson-Morgan reaction and Somogi-Nelson reaction.

(8) Optical rotation ▲ [α] ²⁰ _D ▼: +190.2 9) Melting point: Carbonization at 160 ° C or higher.

10) Fig. 11 shows the ultraviolet absorption spectrum.

11) Fig. 12 shows the infrared absorption spectrum.

The obtained galactosaminooligo-6 sugar was added to the potato dextrose agar medium in the same manner as in Example 1 so that the content was 0.1%.

The same mold as in Example 1 was inoculated, and the no-addition category was used as control 100.
As a result, the antifungal activity of each strain is shown in the table.

[Brief description of drawings]

FIG. 1 is a diagram showing an ultraviolet absorption spectrum of PF-101, FIG. 2 is a diagram showing an infrared absorption spectrum of PF-101, and FIG.
Figure shows the UV absorption spectrum of PF-102, Figure 4 shows the infrared absorption spectrum of PF-102, and Figure 5 shows
Fig. 6 shows the UV absorption spectrum of the fraction of PF-102 degradation product with a molecular weight of 50,000 or more. Fig. 6 shows the infrared absorption spectrum. Fig. 7 shows the molecular weight of PF-102 degradation product of 10,000. Fig. 8 shows the UV absorption spectrum of the fractions above 50,000, and Fig. 8 shows the infrared absorption spectrum of the fractions. Fig. 9 shows the violet spectrum of the fractions of PF-102 decomposition products with a molecular weight of less than 10,000. Figure 10 shows the infrared absorption spectrum of the external absorption spectrum.
FIG. 11 is an ultraviolet absorption spectrum of galactosamino oligo-6 sugar, and FIG. 12 is an infrared absorption spectrum thereof.

Claims (4)

[Claims] 1. An antifungal agent comprising, as an active ingredient, α-1,4 polygalactosamine, a degradation product thereof, or a fractionated product thereof. 2. The antifungal agent according to claim 1, wherein the fraction of the decomposed product of α-1,4 polygalactosamine is α-1,4 polygalactosamine having a molecular weight of 50,000 or more. 3. The antifungal agent according to claim 1, wherein the fraction of the decomposed product of α-1,4 polygalactosamine is α-1,4 polygalactosamine having a molecular weight of 10,000 or more and less than 50,000. . 4. The antifungal agent according to claim 1, wherein the fraction of the decomposed product of α-1,4 polygalactosamine is α-1,4 polygalactosamine having a molecular weight of less than 10,000.