Tip:
Highlight text to annotate it
X
Good morning, my name is Masaya Nagao. I am a Professor in the Laboratory of Biosignals and Response.
In our lab, we search for physiologically active substances from plants that could have practical applications in food and medicine.
We also study the biology of zinc, which is an essential element that is obtained from a normal diet.
I would like to focus on how we search for physiologically active substances from plants.
I explore beneficial substances from plants using a variety of bioassay systems.
By the way, I also teach in the Department of Food Science and Biotechnology, Faculty of Agriculture.
A range of plant-derived substances are used as foods to enhance our health, or as medical products.
Examples of such substances include polyphenols, carotenoids, and alkaloids.
The polyphenol catechin is abundant in tea; β-carotene is found in pumpkins and carrots,
and the alkaloid morphine is extracted from the *** poppy.
These are called secondary metabolites.
While primary metabolites, such as saccharides, proteins, lipids, and nucleic acids, are essential to maintain life,
secondary metabolites are not.
Rather, they are produced mainly to protect plants from enemies, sunlight, dehydration, and other environmental factors.
For example, cucurbitacin, a compound in this family that we identified in the methanol extract of a cucurbit plant,
is responsible for the bitter taste of cucumbers and bitter gourds (Momordica charantia).
It effects actin filaments, which comprise the cell skeleton.
In this video clip, actin filaments are shown in green because actin is expressed as a fusion protein with yellow fluorescent protein (YFP),
which fluoresces with a greenish yellow light.
When cucurbitacin is added to the medium, the normal structure of actin filaments is disrupted,
and the cells change their shape into what we see now.
That is, the plants in the cucurbitaceous family produce cucurbitacin to protect themselves from herbivores, like insects.
As you might expect, Nature has an interesting response to this activity.
A ladybird makes a circular groove in a leaf
and feeds on the unaffected (not bitter) part of the leaf before the feeding induces the production of cucurbitacin.
A cucurbita leaf beetle deliberately feeds on cucurbitacin-containing bitter leaves to make its body taste bitter
and thereby unpalatable to potential predators.
In our lab, we study plants used in Chinese medicine and plants that grow in the North African country of Tunisia.
Tunisia is a small country but its climate and geography range widely from fertile,
Mediterranean soils to barren desert.
This diversity imposes great stress on living organisms.
We are working on a JST/JICA project led by Prof. Hiroko Isoda of the University of Tsukuba.
In this project, we are looking for compounds that are effective in the treatment
and prevention of diabetes and other lifestyle-related diseases.
To do this, we also investigate traditional remedies.
In our research, we extract the various plant components using a solvent.
Then beneficial biologically active compounds are isolated by means of chromatography,
and we characterize the bioactivities of these compounds.
The structure of any beneficial compound is determined by nuclear magnetic resonance (NMR) or other methods,
such as mass spectrometry.
Now Dr. Miyamae will show you how we use the equipment.
Hi, my name is Yusaku Miyamae and I also work at the Laboratory of Biosignals and Response.
I will show you the equipment and explain the techniques we use. in our research.
First, the plant is dipped into organic solvents, such as alcohol, to fully extract the components of the plant.
Then, we use an evaporator to remove the liquid.
A great many different substances are contained in this extract.
From these crude mix of substances,
we isolate those with high purity using a method called chromatography.
First, we roughly divide the components into groups of substances with different properties using column chromatography.
Then the divided components are analyzed at each substance level
with a device called a high-performance liquid chromatograph (HPLC),
which separates the components of a mixture into pure single substances.
Each of these peaks shown here represents a single compound.
The purified substance is analyzed with precision equipment,
such as nuclear magnetic resonance and a mass spectrometer, and finally the chemical structure of the substance is determined.
This is our cultivation room, where we do experiments using cultured animal cells.
We use a clean bench to do experiments with animal cells to keep the area aseptic—free from dust and microorganisms.
A variety of cells, including cancer cells and fat cells, are cultured in this incubator.
Using these cells, we examine the pharmacological activities of the purified substance,
such as its anti-diabetes effects and anti-inflammatory effects.
My name is Taiho Kambe. I am an Associate Professor in the Laboratory of Biosignals and Response.
Our body mainly consists of oxygen, carbon, hydrogen and nitrogen.
These four elements constitute over 95% of our body weight.
However, these elements alone are not enough to support our life.
We also need trace elements, which play a number of indispensable roles.
Our group performs research focusing on these elements, in particular zinc,
from the standpoint of physiology and pathogenesis.
The human body contains only 2--3 g of zinc,
but it plays many crucial roles in our health.
For example, the zinc proteome project estimates that about 10% of the human genome encodes zinc-containing proteins.
Among these proteins, zinc plays structural, catalytic, and regulatory roles in protein function,
which strongly suggests that zinc plays crucial roles in diverse biological processes and thus is required for all living organisms.
Thus, the shortage of zinc causes various health problems.
One well-known example is a taste disorder,
but zinc deficiency causes a broad range of symptoms,
including dysfunctions of the immune system and the nervous system, and severe dermatitis.
Zinc deficiency is responsible for a significant part of the global morbidity and mortality of young children in developing countries,
but recently, mild zinc deficiency has been commonly found in developed countries including Japan.
This is why the media has promoted greater awareness of zinc deficiency.
A number of proteins are employed in the body
for the sophisticated control of systemic and cellular zinc homeostasis.
Among them, zinc transporters are representative ones.
In our body, over 20 zinc transporters are expressed and functional.
Generally, these transporters are divided into two groups ZIP and ZnT.
ZIP transporters function in the uptake of zinc into the cytosol of the cell
from the extracellular space or intracellular compartments,
while ZnT transporters function in the efflux of zinc from the cytosol of the cell
to the extracellular space or intracellular compartments.
The coordinated regulation of both types of transporters is indispensable for proper zinc homeostasis,
and its disturbance has been suggested to be involved
in the pathogenesis and progression of chronic diseases
including diabetes, cancer, and Alzheimer's disease.
Our group performs research on zinc transporter functions with the aim of promoting general health,
and also to discover novel information for the prevention and treatment of various diseases
by elucidating multifarious functions of zinc in our body.