Collaborative research


Evaluating the biological effects of natural compounds on diverse plant materials

Takumi Higaki,Takashi Ideue

In this study, we will apply natural compounds that inhibit the proliferation of cultured plant cells to various plant materials and yeast, to conduct a comprehensive evaluation of their biological activities.

Through this study, we aim to identify agriculturally beneficial biological activities or potential side effects, exploring the possibilities for the practical application of these natural compounds.

Inactivation of plant-knot nematodes by pulsed power

Douyan Wang,Allen Yi-Lun Tsai

Pulse power is instantaneous electrical energy that can stimulate plant-knot nematodes without damaging plant roots.

This research aimed to inactivate the plant-knot nematodes in Tomato roots by applying pulsed power to the roots.

Screening of deep-sea yeasts and industrial applications

Tokio Tani,Sachiko Tsukamoto

The microbiota of the deep sea (the part of the ocean deeper than 200 m), which accounts for 95% of the Earth‘s total ocean surface, remains mostly unknown. In particular, little research has been done on deep-sea yeasts. In this joint research project, deep-sea sediments (e.g., 6,000-m sediments in the Izu-Ogasawara Trench) provided by Japan Agency for Marine-Earth Science and Technology (JAMSTEC) will be screened to isolate yeasts that inhabit the deep-sea floor. Species (genus) identification will be conducted by sequencing the rRNA genes of the isolated yeasts, including uncharacterized deep-sea yeasts that have already been isolated by JAMSTEC. We aim to apply the identified deep-sea yeasts to the brewing and pharmaceutical industries by further analyses of the fermentation characteristics and functional compounds present in the deep-sea yeasts.

3D modeling of leaf movement

Miyuki T. Nakata,Takumi Higaki

In some groups of plants, including crops, leaf movement is observed, which are driven by the cells of a motor organ called the pulvinus. The movement of plant leaves can contribute to the efficient use of light and the avoidance of photodamage.

In this collaborative research project, as a first step towards elucidating the responses of leaf movement to light environments and its correlation with growth, we will establish the 3D models of leaves and quantitative data analysis.

Discovery of nematode infection antagonists from fungi

Yuki Hitora,Allen Yi-Lun Tsai

Plant-parasitic nematodes cause severe damage to many crop species. To reduce crop damages from nematodes and promote sustainable agriculture, the development of novel nematode infection antagonists derived from natural products is in demand. In this study, we investigate nematode infection antagonists from fungal secondary metabolites.


Exploration of stomata-targeted plant bio-stimulantsent using graphene oxide

Takumi Higaki,Yuki Hitora,
Sachiko Tsukamoto

Stomata are tiny pores on the surface of plant leaves and stems, and their opening state is tightly regulated in response to the environment.
In this study, we aim to identify plant growth regulators with low environmental impacts (bio-stimulants) using intracellular localization of stomata regulatory proteins as markers, by making combining our expertise in natural compounds and image analysis.

Studies on effect of sulfur compounds on oxidative stress in fish and sex differentiation

Takeshi Kitano,Takuro Niidome

Prof. Kitano has reported that when medaka hatchlings experience oxidative stress, genetically female individuals masculinize, and this effect is negated by a cysteine derivative. On the other hand, this cysteine derivative was also shown to be a powerful antioxidant. Furthermore, Prof. Niidome is now synthesizing various sulfur compounds to act as future screening candidates.

In this study, sulfur compounds synthesized by Prof. Niidome were tested on medaka for their effects on sexual differentiation and redox state (glutathione level) in fishes. This research can be applied in aquaculture to selectively produce females, which have higher market values than males.

Research tasks breakdown:
1. Sulfur compound synthesis (Niidome)
2. Sulfur compounds treatments of medaka, female differentiation rate evaluations (Kitano)

Activation of fungal secondary metabolism using pulsed power: induction of plant growth-promoting agent synthesis

Yuki Hitora,Sachiko Tsukamoto,
Douyan Wang,Takao Namihira, andTakumi Higaki

Fungi produce a variety of useful compounds such as pharmaceuticals, agrochemical products, and functional ingredients. In addition, fungal metabolites can strongly influence plant growth and are expected to have great potential in agriculture.

Pulsed power is a form of energy released instantaneously, and is used in a wide range of research. Pulsed power stimulation has been reported to increase shiitake mushroom production, thus may enhance fungal growth and metabolism.

This study aims to develop technologies to increase the synthesis of fungi-derived useful compounds through pulsed power.

Leaf development and image analysis

Mitsuhiro Aida,Masashi Toda,Takumi Higaki

We aim to develope imaging methods for quantitative evaluation of leaf traits, applying this method to perform functional analyses of genes involved in leaf development.

Construction of Kumamoto regional yeast library using cell morphology, and its applications in food industries

Tokio Tani,Takumi Higaki

In this joint research project, wild yeast strains found in the Kumamoto prefecture will be collected from fruits, flowers, plants, and soil to construct a local yeast library. We will establish a novel, rapid yeast classification and identification workflow by linking cell morphology with rRNA sequence information. This Kumamoto local regional yeast library can potentially identify useful yeast strains that contribute to the brewing and fermentation industry.


Identification of pesticide candidates from fungi-derived volatile organic compounds

Sachiko Tsukamoto,Yuki Hitora,Kei Toda

This research aims to isolate volatile organic compounds secreted by fungi, and evaluate their effects on plant pathogens, pests, and plants themselves in order to identify candidate agricultural pesticides.

Exploration of candidate pesticides, pharmaceuticals and health supplements through natural products and image analysis

Yuki Hitora,Sachiko Tsukamoto,
Takumi Higaki

This research aims to use image analysis and machine learning to screen for candidate health supplements from natural products that alleviates or prevents osteoporosis.

Discovery of candidate pesticides through plant cell culture assays

Takumi Higaki,Sachiko Tsukamoto,
Yuki Hitora

This research aims to discover compounds from natural resources that regulate plant cell growth, as candidate pesticides.

Effects of graphene oxide on plant growth regulatory substances and crop production

Mitsuhiro Aida,Shinya Hayami

The cells required for plant growth are formed in the apical meristems at the shoot and root tips. The cell division activities in these meristems are controlled by plant growth regulatory substances (phytohormones, etc.), which in turn affects other crop plant properties such as leaf, shoot and root developments, branching, and fruit/seed yields. This research project examines how the high surface area and adsorption-desorption properties of graphene oxide affect plant growth and phytohormone activities. Furthermore, the viability of graphene oxide as an antistripping agent during plant microscopy will be evaluated.

Analysis of fatty acids’ effects on the sexual determination in farmed fishes and their mechanisms

Takeshi Kitano,Tokio Tani,Takashi Ideue

Among farmed fishes, species such as eels and flounders produce females that grow faster than males, while others such as the tiger puffers produce male gonads that are highly valued. Therefore, there are strong incentives to produce single-sex populations in fish-farming (Fig. 1). The Kitano group has identified the fatty acid receptor PPARα to positively regulate male development, suggesting fatty acid plays a role in sexual determination. On the other hand, the Tani/Ideue group has identified one of the fatty acids, myristic acid to block the formation of intracellular structures called nuage uniquely found in reproductive cells (Fig. 2), though the molecular mechanism remains unclear. This research aims to determine the viability of using fatty acid to control sexual determination in farmed fishes, and the associated molecular mechanisms. The first steps include:
1. Determine which fatty acids promote male development when used to treat the model organism Japanese rice fish (Kitano group)
2. Determine which fatty acids affect nuage formation in insect cell culture, and characterize the molecular mechanisms of these activities (Tani/Ideue group)
With the effects of fatty acids in sexual determination delineated, their utility in fish-farming can then be evaluated.

World’s first fission yeast-fermented liquor: the development of Schizosaccharomyces japonicus strain Kumadai

Tokio Tani,Kei Toda,Takashi Ideue

We aim to commercialize the world’s first fission yeast-brewed liquor, by engineering Schizosaccharomyces japonicus strains with enhanced fragrance production to elevate the liquor’s flavor and scent complexity. The high ethyl caproate-producing strain Kumadai T-11 isolated by the Tani/Ideue group can be used to screen for more strains that produce other fragrances such as phenethyl alcohol and isoamyl acetate. These strains will then be analyzed by the Toda group’s gas chromatography for scent composition, to select for strains suitable for liquor-brewing. Candidate strains will be tested at the Kumamoto Industrial Research Institute to finalize strain selection. By collaborating with Kumamoto local breweries, we aim to commercialize liquors brewed using these novel fission yeast strains.

Development of feeds made of silk worm that control sexual determination of fish

Takuro Niidome,Takeshi Kitano

Female farmed eels and flounders are more profitable than their male counterparts, and the control of sexual determination will be a key technique for fish farming. Kitano's group has characterized sexual determination mechanism using the model fish, Japanese medaka (Oryzias latipes), and has identified a fatty acid receptor PPAR involved in sexual determination. Niidome's group has developed a technique for transgenic silk worms to express proteins in silk worm larvae, pupae and cocoons. This research aims to develop fish feeds composed of silk worm that control sexual determination in farmed fishes. Preliminary objectives include:
1. Examine whether silk worm larvae and pupae can be served as feeds for Japanese medaka, either in paste or dried powder forms.
2. Evaluate whether sexual determination of Japanese medaka can be controlled by fatty acids known to affect sexual development added to the feeds.

Agriculture in arid environment using graphene oxide

Shinya Hayami,Shinichiro Sawa

Water is an extremely important resource in arid environments. Effective use of limited water is critical not only for human living conditions, but also crop production in dry areas. Specifically, water retention is an important point for agriculture with limited water. Since soil water retention capacities are finite, application of moisturizer as soil conditioners may be a viable strategy to improve water retention. Currently we are developing practical uses of absorbent polymers, and we propose using graphene oxide as a soil water retention agent.