JP4691307B2 - Microbial growth control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling the growth of microorganisms by controlling the growth of microorganisms by light irradiation and improving the culture technique of the microorganisms.
[0002]
[Prior art]
With regard to the effect of light on the growth of microorganisms, it is well known that light in the ultraviolet region significantly inhibits the growth of microorganisms. It has also been clarified that microorganisms such as photosynthetic bacteria require red light of around 660 nm and blue light of around 430 nm for photosynthesis and growth. However, little is known about the effects of light in the visible region other than the ultraviolet region on the growth of microorganisms other than photosynthetic bacteria, and as a result, cultivation of microorganisms other than photosynthetic bacteria is generally performed in the dark. is the current situation.
[0003]
On the other hand, in culturing microorganisms, it is important to establish a technique for artificially culturing beneficial microorganisms such as mycorrhizal fungi that are one of the filamentous fungi. Mycorrhizal fungi are one of the symbiotic microorganisms that infect plants and help them absorb nutrients, and are the symbiotic microorganisms that are currently attracting much attention in building sustainable cultivation systems with low inputs. Because. Although this bacterium is a plant symbiotic bacterium and it has been said that pure culture is impossible until now, one of the present inventors, Ishii et al. Cultivates VA mycorrhizal fungi artificially without using live plant roots. Technology was the first in the world to succeed (see, for example, Patent Document 1). In the case of this bacterium, there is also a report that spore formation is inhibited when light enters the container in the culture using hairy roots (see, for example, Non-Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-191685
[Non-Patent Document 1]
Tatsuo Hayashi, Hiroshi Adachi, Hidehiko Ishimaru, Genetics 47 (7), 1993, p. 66-71
[0006]
[Problems to be solved by the invention]
However, the above-described culture technique (the light environment condition is dark) has a problem that mycelium growth is slow and it takes time until sporulation occurs.
[0007]
This invention is made | formed in view of such a point, and it aims at providing the growth control method of microorganisms which can aim at the improvement of a culture technique.
[0008]
[Means for Solving the Problems]
Growth method of controlling microorganisms according to claim 1 is rhizopogon roseolus bacteria, matsutake fungi, one of the microorganisms of rapeseed anthracnose fungus and Uri anthrax bacteria, cultured under irradiation of light in the light wavelength region from about 600nm to 800nm Thus, the growth of this microorganism is promoted.
[0009]
Then, rhizopogon roseolus bacteria, matsutake fungi, one of the microorganisms of rapeseed anthracnose fungus and Uri anthrax bacterium by culturing under irradiation of light in the light wavelength region from about 600nm to 800 nm, promotes the growth of the microorganism Therefore, it is possible to improve the culture technique of this microorganism.
[0010]
The method for controlling the growth of a microorganism according to claim 2, wherein any one of the microorganisms of Drosophila, Tricholoma matsutake, Brassica anthracnose, Uri anthracnose , Bacillus subtilis and Staphylococcus aureus is placed in a light wavelength region from about 400 nm to 490 nm. Cultivation under certain light irradiation suppresses the growth of these microorganisms.
[0011]
Then, by cultivating any one of the microorganisms of S. cholera, matsutake, rape anthracnose, cucurbit anthracnose , Bacillus subtilis and Staphylococcus aureus under light irradiation in the light wavelength region from about 400 nm to 490 nm To suppress the growth of these microorganisms and to promote the formation of spores in S. cholera, matsutake, rape anthracnose , cucurbit anthracnose , Bacillus subtilis and Staphylococcus aureus. It is Ru can.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
As a result of studying how light quality affects the growth of microorganisms using various light emitting diodes, etc., irradiation of far red light from colored light promotes the growth of microorganisms, while irradiation of blue light Has found that sporulation is promoted by suppressing the growth of microorganisms. The tested microorganisms are filamentous fungi such as Drosophila, Tricholoma matsutake, Brassica anthracnose fungus, Worm anthracnose fungus, and bacteria such as Bacillus subtilis IAM12021 and Staphylococcus aureus 3062.
[0013]
Note that the color light to far-red light is light in the light wavelength region from approximately 600 nm (nanometer) to 800 nm. The blue light is light in the light wavelength region from about 400 nm to 490 nm.
[0014]
As a result of research, the growth of microorganisms was promoted by culturing under irradiation with light from far-red light to far-red light, and growth of microorganisms was suppressed by culturing under light irradiation with blue light. It was found that the growth of spore was inhibited and sporulation was promoted. That is, the present invention provides a technique for controlling the growth of microorganisms by light irradiation that causes the growth or suppression of microorganisms and a technique for artificial culture of microorganisms.
[0015]
Therefore, the growth of microorganisms, particularly filamentous fungi, is controlled by irradiating far red light or blue light from colored light to improve the culture technique. In addition, the microorganisms in which the effect of light irradiation is often seen are particularly filamentous fungi, and the growth of these microorganisms can be controlled to improve the culture technique.
[0016]
According to the present invention, it is recognized that the light quality has a significant influence on the growth of microorganisms, particularly filamentous fungi. Therefore, the growth of microorganisms is promoted by light irradiation in the wavelength range from orange to far-red light, and the growth of microorganisms is promoted by suppressing the growth of microorganisms by light irradiation in the blue light wavelength range. It is useful for providing control technology and its culture method.
[0017]
【Example】
Next, the present invention will be described in more detail with reference examples and examples.
[0018]
Reference Example 1 [Effect of culturing under dark and white light and red light of fluorescent lamp on VA mycorrhizal mycelium growth] Basic medium (Hidenori Muramatsu, Takaaki Ishii, Isao Matsumoto, Kazuomi Kadoya, Horticultural Society) 64, volume 2, 1995, pp. 106-107), 10 ml of a medium in which glucose was replaced with mannitol 50 ppm was put into a petri dish (diameter 70 mm), sterilized by autoclaving (121 ° C., 15 minutes), and then surface sterilized. Gigaspora margarita spores were placed on the medium. Thereafter, the cells were cultured for 1 week in the dark at 27 ° C. and in the white light of a fluorescent lamp (light intensity: 30 μE · m-2s-1) and red light (light intensity: 10 μE · m-2s-1). The growth of mycelia from spores was measured by an image processing method using a stereomicroscope equipped with a camera and a personal computer (Ishii et al., Horticultural Society Journal 65 (3), 1996, p. 525-529). The wavelength of red light has a peak at 660 nm as shown in FIG. As a result, the mycelial length was 1 to 2 mm under dark and white light of fluorescent lamps, but no significant difference was observed. Under red light, the growth was 4 to 9 times that of dark or white light. A promoting effect was observed (FIG. 2).
[0019]
Reference Example 2 [Effect of Light Irradiation by Light-Emitting Diodes (LED) of Various Wavelengths on Gigaspora Margarita Mycelium Growth] Surface-sterilized Gigaspora margarita spores were used as the basic medium used in Reference Example 1. Place on medium supplemented with 25% MeOH eluate (0.1 g DW / 10 ml) (use petri dish with 70 mm diameter) and peak in the dark at 27 ° C. and wavelengths of 450 nm, 510 nm, 590 nm, 612 nm, 660 nm and 730 nm The cells were cultured for 10 days under the LED (FIG. 3, light intensity: 10 μE · m−2s−1), and the mycelial length was measured in the same manner as in Reference Example 1. In addition, at 660 nm, it investigated also under light intensity of 40 microe * m-2s-1. As a result, also in Reference Example 2 using LEDs, light irradiation in the red region of 612 to 730 nm showed a remarkable mycelial growth promotion effect 3 to 5 times that in the dark. Moreover, the difference by light intensity difference was not recognized up to 40 μE · m−2s−1. Under 510 nm and 590 nm, no significant difference was observed between dark and dark. On the other hand, mycelial growth was remarkably suppressed by irradiation in the blue region near 450 nm (FIG. 4).
[0020]
Example 1 [Effect of Light Irradiation by Light-Emitting Diodes (LEDs) of Various Wavelengths on Growth of Drosophila and Tricholoma matsutake Mycelium In addition, agar containing hyphae (diameter: 7 mm) from an agar medium in which Drosophila and Tricholoma matsutake were cultured in advance ), And each planted in MMN medium. Then, it culture | cultivated under 27 degreeC red light, blue light, and darkness, and the hyphal growth in each process division was compared and investigated. As a result, almost the same results were obtained with the bacterium Shou and Matsutake, and mycelial growth was promoted under irradiation with red light and inhibited under irradiation with blue light compared to that under dark conditions (FIGS. 11 and FIG. 11). 12).
[0021]
Reference Example 3 [Effect of light irradiation by blue light LED (BL) on mycorrhizal mycelium growth] The effect of blue light was investigated in more detail. That is, the spores of Gigaspora margarita (Gigaspora margarita) sterilized by the same method as in Reference Example 1 were placed on the medium used in Reference Example 2 (using a petri dish having a diameter of 70 mm), and under red light at 27 ° C. Pre-cultured for 2 weeks. Thereafter, there were provided 6 treatment zones of darkness, darkness after irradiation with 450 nm (blue light LED) for 0.25, 0.5, 1, 3 hours (h), and further continuous BL light irradiation. The light intensity of the blue light was 50 μE · m−2s−1. After 0, 1, 3 and 6 days of treatment, hyphal elongation was measured in the same manner as in Reference Example 1. As a result, no significant difference was observed in the dark areas after irradiating blue light of 0.25 h, 0.5 h, and 1 h as compared with the continuous dark areas. In the irradiated area, a remarkable growth suppression effect was observed (FIG. 5). FIG. 6 is a photomicrograph showing the mycelial growth of the dark area and the blue light irradiated area for 3 hours before the blue light treatment and 6 days after the blue light treatment.
[0022]
Reference Example 4 [Effect of Light Irradiation with Red Light and Blue Light LED (BL) on Growth of Blue Mold] The mycelium is removed from a PDA (potato dextrose agar) medium in which this blue mold has been pre-cultured, and again into a sterile PDA medium. Planted. Then, it culture | cultivated under 27 degreeC red light, blue light, and darkness, and compared and investigated the hyphal growth and spore formation state in each processing section. The light intensity of the red light and blue light LEDs was 30 μE · m−2s−1. As a result, as in the case of mycorrhizal fungi, in the case of blue mold, mycelial growth was promoted under irradiation with red light as compared with under darkness, and on the contrary, it was inhibited under irradiation with blue light (FIG. 13). In the blue mold, it was observed that many spores were formed in the petri dish in the blue light irradiation section.
[0023]
Example 2 [Effect of Light Irradiation by Red Light and Blue Light LED (BL) on Growth of Brassica Anthracnose Fungus and Woolly Anthracnose Fungus] PDA (Potato Dextrose Agar) Medium Cultured in advance The mycelium was taken from and again planted in sterile PDA medium. Then, it culture | cultivated under 27 degreeC red light, blue light, and darkness, and compared and investigated the hyphal growth and spore formation state in each processing section. The light intensity of the red light and blue light LEDs was 30 μE · m−2s−1. As a result, as in the case of mycorrhizal fungi, both rape anthracnose fungus and cucurbit anthracnose fungus promoted mycelial growth under red light irradiation and, on the contrary, inhibited under blue light irradiation as compared to darkness. (FIGS. 7 and 8). In the case of rape anthracnose fungus and cucumber anthracnose fungus, it was observed that many spores were formed in the petri dish in the blue light irradiation zone.
[0024]
Example 3 (Effect of light irradiation by blue light LED (BL) on the growth of Bacillus subtilis IAM12021 and Staphylococcus aureus 3062) Take these bacteria from a pre-cultured peptone agar medium, Again, they were planted in sterile peptone medium. Then, it culture | cultivated under 27 degreeC blue light and darkness, and investigated the effect which blue light irradiation has on the growth suppression of bacteria. The light intensity of the blue light LED was 30 μE · m−2s−1. As a result, it was observed that bacterial growth tended to be slightly suppressed under blue light irradiation as compared to darkness (FIGS. 9 and 10).
[0025]
【The invention's effect】
According to the growth method of controlling microorganisms according to claim 1, rhizopogon roseolus bacteria, matsutake fungi, one of the microorganisms of rapeseed anthracnose fungus and Uri anthrax bacteria, under irradiation of light in the light wavelength region from about 600nm to 800nm Since the growth of the microorganisms can be promoted by culturing in this manner, the cultivation technique of the microorganisms can be improved.
[0026]
According to the method for controlling the growth of microorganisms according to claim 2, any one of the microorganisms of Drosophila, Tricholoma matsutake, Brassica anthracnose, Cucurbit anthracnose , Bacillus subtilis and Staphylococcus aureus has a light wavelength of about 400 nm to 490 nm. by culturing under irradiation of light in the region, since it inhibited the growth of this microorganism, Ru can be improved culture techniques of this microorganism.
[Brief description of the drawings]
FIG. 1 is a diagram showing a wavelength spectrum of a red fluorescent lamp used in Reference Example 1. FIG.
FIG. 2 is a diagram showing mycelial growth of VA mycorrhizal fungi in the darkness examined in Reference Example 1, and in each of white light and red light by a fluorescent lamp.
FIG. 3 is a diagram showing the wavelength spectra of all LEDs used in Reference Example 2 and Example 1. FIG. 4 shows darkness and 450 nm, 510 nm, 590 nm, 612 nm, 660 nm, and 730 nm investigated in Reference Example 2. It is a figure which shows the mycelial growth of VA mycorrhizal fungi in the LED light irradiation area of a wavelength.
FIG. 5: Mycorrhiza in darkness 6 days after treatment examined in Reference Example 3, darkness after 0.25, 0.5, 1, 3 hours of blue light (BL) irradiation and further continuous BL light irradiation It is a figure which shows the mycelial growth of a fungus.
6 is a photomicrograph showing mycelial growth of mycorrhizal fungi in the dark area and the 3-hour BL light irradiation area before and after 6 days of blue light (BL) treatment examined in Reference Example 3. FIG.
7 is a graph showing the growth of Brassica anthracnose fungi in the darkness, red light and blue light irradiation areas examined in Example 2. FIG.
FIG. 8 is a graph showing the growth of cucumber anthracnose fungi in the darkness, red light and blue light irradiation areas examined in Example 2.
9 is a photograph showing the growth of Bacillus subtilis IAM12021 in the blue light-irradiated area examined in Example 3. FIG.
10 is a photograph showing the growth of Staphylococcus aureus 3062 in the blue light-irradiated area examined in Example 3. FIG.
FIG. 11 is a table showing the growth of Drosophila in the dark, red light and blue light irradiation areas examined in Example 1.
12 is a table showing the growth of matsutake fungi in the darkness, red light and blue light irradiation areas examined in Example 1. FIG.
FIG. 13 is a table showing the growth of blue mold in the darkness and red light and blue light irradiation areas examined in Reference Example 4.

Claims (2)

Rhizopogon roseolus bacteria, matsutake fungi, one of the microorganisms of rapeseed anthracnose fungus and Uri anthrax bacteria, cultured under irradiation of light in the light wavelength region from about 600nm to 800 nm, that to promote the growth of the microorganism A method for controlling the growth of microorganisms. A microorganism of any one of Pseudomonas, Tricholoma matsutake, Brassica anthracnose, Uri anthracnose , Bacillus subtilis, and Staphylococcus aureus is cultured under irradiation with light in a light wavelength region of approximately 400 nm to 490 nm. A method for controlling the growth of microorganisms, characterized by suppressing the growth of microorganisms.

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