List of Dissertation Abstract (Department of Natural Environment)
Name
SHOU LU

Supervisor
Kagami
MaikoTitle

Abstract

Phenotypic and genetic diversity
within a fresh water diatom species,

We investigated the intraspecific diversity of Aulacoseira
ambigua, which is widely distributed in mesotrophic andeutrophic freshwater lakes, by measuring phenotypic
traits and evaluating genetic diversity by double-digested
restriction site-associated DNA sequencing.Our results
revealed the phenotypic and genetic diversity within A.
ambigua. The growth rate and susceptibility to parasitewere both correlated with morphological traits. ddRADseq identified that twenty-six SNPs associated withphenotypes.. The distance-based redundancy analysis
based on neutral SNPs explained that relationshipbetween genetic and phenotypic similarity were notsignificant.
On Yakushima Island, which has a rich natural ecosystem,
the negative impact on the natural ecosystem andagricultural damage caused by the increasing populationof the Yakusika (Cervus nippon yakushimae), an endemic
species, are considered problematic. In this study, I
estimated the population of Yakushika using a state-spacemodel and examined how to apply pressure to capture
Yakushika in specific areas of Yakushima. As a policy for
future management of the Yakushika population, it isnecessary to apply strong hunting pressure in thesouthwestern and central areas to reduce the population,and to reduce hunting pressure in the northeastern area
to allow the population to recover.

Aulacoseira ambigua

Ikariya Taisei

MatsudaHiroyuki

Improving the accuracy ofYakushika (Cervus nipponyakushimae) population analysis
methods and population
management models.

Itagaki HarukaIshikawa
Masahiro

Distribution and seasonal evolutionof supraglacial lakes on the AmeryIce Shelf, East Antarctica

The distribution of glacial lakes on the Amery Ice Shelf in
East Antarctica and the seasonal changes in area andvolume were determined by analyzing Landsat 8 satellite
images.Most of the glacial lakes were formed around thegrounding line, around exposed rocks, and below 250 m
elevation. The glacial lakes began to form at the end ofNovember, expanded from December to January, andcontracted at the end of February.

Inoue Risa

SasakiTakehiro

Reconsidering the food system tomitigate impacts on climate change
and biodiversity loss

Beef production has a greater environmental impact thanother foods containing protein. In recent years, economic
growth has led to an increase in beef consumption, andthe accompanying increase in obesity and lifestyle-relateddiseases has become an issue. In addition, the increase ininternational trade has made it difficult for consumers to
see the environmental impact in the producing countries.
In this study, we estimated the effect on theenvironmental impact of reducing beef consumption tothe values proposed in previous studies to realize asustainable and equitable society, taking trade relations
into account and focusing on biodiversity impact,methane emissions, and lost carbon sequestration
opportunities.

Kizawa ryosakai akiko

Effects of Climate Change onJapanese Pine Communities in the
Northern Hakkouda Mountains:
Focusing on Changes in Dominant
Zone and Growth Rate

Kiyono Sachi

Hiratsuka
KazuyukiTranscriptional repression of plant
genes using dCas9/sgRNA-based
artificial transcription factors

In the North Hakkouda Mountains, the distribution areaof Pinus pumila has been shifting to higher elevations.
High-resolution UAV photo-reading and fieldobservations suggest that the distribution area hasexpanded by replacing dwarf shrubs such as Empetrum
nigrum, and has been reduced by the replacement ofsubalpine species such as Abies mariessi, sasa kurilensis,and shrubs. The growth rate of the Pinus pumila dropped
drastically after 2013. The growth rate was influenced not
only by non-biological factors, such as slope direction andelevation, but also by biological factors, such as thepresence or absence of competing species.
In recent years, attention has focused on highperformance plants with added value, such as disease
resistance. Artificial regulation of gene expression isrequired to produce such plants. Transcriptional
repression using the dCas9/sgRNA system, which ischeap, simple and highly accurate, is considered to be auseful tool for this purpose. In this study, we attempted tosystematically regulate gene expression by targeting
specific genes in plants using the dCas9/sgRNA system
and aimed at its application.

SatakeYoshitaka

YamamotoShinji

Sr and Y analysis of apatite inzircon from Jack Hills, Western
Australia -Estimation of host rockof zircon and apatite forinvestigation of the origin of Earth’s
water-Seto Tomohiro

Koike Fumito

Invasive plant eradication andsubsequent vegetation restoration
on Anijima, Ogasawara Islands,Japan.

Various studies have been conducted to elucidate theorigin of water on the earth, but a unified view has notbeen obtained. However, three candidates have beenconsidered, which have different hydrogen isotope ratios.
In this study, hydrogen isotope analysis of apatite inzircon, which is the oldest material on earth, was carriedout to elucidate the origin. In addition, apatite in zircon
crystallized from different magmas, each with differenthydrogen isotope ratios. In order to estimate the magmafrom which apatite and zircon crystallized, these traceelements were analyzed.
The Ogasawara Islands, which are oceanic islands, wereinscribed on the World Heritage List in recognition of
their unique ecosystem and scientific value. About 10years ago, each management agency took the lead in
implementing invasive plant control measures to preserve
the endemic forest ecosystem. In this study, I analysed thegrowth environment and invasion status of major invasiveplants on Anijima, and the vegetation transition before
and after invasive plant eradication, using data obtained
from the invasive plant control project. As a result of theanalysis, it was found that native forests acted as a barrier
to the establishment of some invasive plant species, and a
new importance of native forest conservation was found.
In addition, it was found that there was a difference insuccessional trends after invasive plant eradication,
depending on the species eradicated.

TakeuchiRyunosuke

Koike Fumito

Insect Food Breadth and theInvasive Alien Species Problem.
The case of Fabaceae andAsteraceae

In recent years, the invasion and establishment of exotic
plants and other alien species have had a major impact on
ecosystems. Most insects are unable to utilize non-nativeplants due to their high host specificity, but if a nonnative plant is successfully utilized, the insect species may
experience an outbreak because defense mechanisms on
the plant side have not developed along with coevolution.
Therefore, we investigated the impact of non-nativeplants on insects at the community level and by use of theplants and the insects that utilize them in the Fabaceae
and Asteraceae families. As a result, a trend toward large
populations and outbreaks of non-native insects wasobserved. However, the reason for the particularly large
populations of exotic insects in combination with exotic
plants is unclear and may become clearer when we trace
the history of the development of parasitic insects andchanges in their population control after they become wildin many dominant exotic plants.No tendency was detectedfor exotic plants to be less susceptible to parasitism thannative plants, as there was no trend toward predominant
insect populations. However, a trend toward greater useof exotic plants by nectar-sucking insects was detected.
This may be due to the relatively low host-specificity ofnectar use, which may result in higher use of non-nativeplants.Translated with www.DeepL.com/Translator (freeversion)

Tsuchihashi
YuiSasaki
Takehiro

Nakai Hiromi

Hiratsuka
Kazuyuki

Vegetation change in mountainwetlands since the early Showa
period: analysis focusing on thenested structure of species
distribution

Plants change their vegetation over time. Therefore, weconducted a vegetation survey of mountain wetlands
scattered in the Hakkouda Mountains area of Aomori
Prefecture, Japan, to estimate ecological processes in pastand present marshland communities based on changes inthe spatial distribution patterns of species. The results
suggest that the spatial distribution patterns have changed
and that the marshland has become homogenized fromthe past to the present. The results also suggested that thehabitats of woody and non-wetland species are expanding.
Screening for novel compounds that Plants have various defense mechanisms to protect
act on jasmonate signaling pathway themselves from biotic and abiotic stresses. Activation ofthese defense mechanisms by chemicals is expected tolead to plant protection and highly efficient material
production using plants. However, there are still few
chemicals that act on jasmonate signaling pathway, one ofthe defense mechanisms. In this study, we developed asystem to screen novel compounds that activate jasmonate
signaling pathway.

NAKAZAWA
KENTA

NAKAMURA Mechanism of cancer cell death byTATSUOhyperthermia using magnetic
nanoparticles

Nakamura Ai

OikawaHiroki

Are satoyama conservation
activities covered by a "sense ofstagnation"?

This study examined the dispersibility of magnetic
nanoparticles as a medium for MHT and the mechanismof cell death after HT. Magnetic nanoparticles were able
to control the secondary particle size to less than 1 µm byusing originally devised ultrasound. Furthermore, whencancer cells were subjected to hyperthermia, they werefound to be in apoptosis, and since the HT effect wasthought to be related to heat shock protein (HSP),
measurements were made and HSP was found to bepredominantly increased.
With the institutionalization of citizen participation,citizen groups are said to be covered by a "sense ofstagnation. In order to clarify the degree and existence ofa "sense of stagnation," I conducted a survey of one civic
group as a case study, focusing on the decline in"enjoyment. As a result, no "sense of stagnation" wasidentified in this survey. It was also found that there was apositive aspect as an effect of institutionalization.

NakamuraKahoKazuyuki
Hiratsuka

Probing the Dynamics of Oxytocin
in the Brain Tissue

Nitta Saya

Koike Fumito Do vegetation boundaries
contribute to plant diversity as
spatial structures?

Oxytocin is a type of peptide known for its strong central
actions, in addition to the long-known peripheral actions.
Despite increasing realization of its importance, dynamics
and sites of action of oxytocin in the brain are poorly
understood due to a lack of appropriate probe. To thisend, we conjugated oxytocin with “alkyne-tag” via awidely applicable simple coupling reaction. In thisresearch, we developed a novel strategy and found regionspecific binding sites and dynamics of oxytocin in thebrain tissue.
Boundaries" such as the boundary between a road and agrassland or between bare land and a grassland are special
environments. Few studies have focused on plants native
to the boundaries of grassland vegetation at small spatial
scales, and the differences in species composition fromthe interior and their ecological characteristics have notbeen elucidated. In this study, we attempted to detect
trends in species occurrence at "boundaries". The resultsshowed that boundaries contribute to diversity and thatmultiple ecological characteristics are related to thetendency of occurrence at boundaries.

Fukumaru
FumikaHiratsuka
KazuyukiCharacterization of a novelcompound that activates a wide
range of defense responses

Maehara Kaho

SasakiTakehiro

Plant and soil microbial community
assembly processes across urban
vacant lots

Plants are exposed to various pathogens in theenvironment and have their own defense mechanisms toprotect themselves from them. Plant activator, the subjectof this research, are agents that protect plants byactivating Induced Systemic Resistance (ISR), one of theirdefense mechanisms. In this study, I have characterized
the actions of a Plant activator candidate compound thatinduces a wide range of disease responses, which wasdiscovered by our original screening system, using
methods such as gene expression analysis.
Plant and soil microbial communities can play an essential
role in maintaining ecosystem functions and services inurban ecosystems. However, community assembly inhuman-dominated urban ecosystems is not well known. In
this study, we investigated plant and soil microbialcommunity assembly processes in 69 vacant lots in
Yokohama, Japan, which were developed for residentialuse. Our results suggest that plant community assembly
processes in urban vacant lots are determined by dispersal
limitation and that soil microbial community assembly
processes are stochastically determined due to theirubiquitous dispersal capacity.

YamadaHayamiNakamura
TatsuoPhenotypic analysis of candidate
alkaline response-related genes
using gene disruption Arabidopsis
thaliana

Yamamoto
SumireSasakiTakehiro

Consequences of urbanization on
long-term changes in biotic
communities in remnant habitats in
the Tokyo metropolitan area

More than 7 % of the world's total land area, comprising
about 1.128 billion hectares of land, is affected by saline
alkaline stress. Alkaline salt stress causes more severe
damage to plants than neutral salt stress under highsalinity and pH conditions, but how plants sense salt
stress and alkaline stress signals is not yet fully
understood. Detailed phenotypic analysis was performedon gene disruption Arabidopsis plants that were found tohave alkaline stress-related responses based on previous
studies using GWAS.
Little research has been conducted to show theconsequences of urbanization on long-term changes inbiotic communities in several remnant habitats. In thisstudy, I collect rare biota inventories and discuss theconsequences of urbanization on from several years to
decades changes in biotic communities in 15 remnant
habitats in the Tokyo metropolitan area. Regarding
changes in number of species, the change in number ofnative plants was reflected to that of all plants. However,nonnative plants were also increased in most of the siteswhere both all plants and native plants were increased.
Regarding changes of species composition and theirfactors, there is a possibility that the change of nonnativeplants with allochory caused the change of birds. Inaddition, the larger the remnant green space is, thesmaller the change of native plants is.

Yoshimura
Moe

Hiratsuka
Kazuyuki

Search for factors that improve
Agrobacterium-mediated transient
gene expression

The soil bacterium Agrobacterium is often used to
produce transgenic plants. However, when a gene transfer
into a plant, a phenomenon may occur in which the gene
expression efficiency of the transgene is reduced. In thisstudy, I searched for new compounds that improve
Agrobacterium-mediated transient gene expression. As aresult, 16 potentially useful compounds were discovered.

Heikkinen
Mirka

SasakiTakehiro

Overlooked diversity of
spontaneous plants in urban
streetscapes in Oulu and Yokohama

In this study, urban street vegetation was investigated inOulu, Finland, and Yokohama, Japan, to explore how
plant species richness and species composition change
among various street habitat types. The species richness
and the contributions of native and exotic species wereevaluated, and the plant species composition wasexamined. In Oulu, native species contributed more to thetotal diversity, whereas in Yokohama, native and exotic
species had similar contribution to the total diversity.
There was overlap in species occurrence among habitat
types, but also many habitat-unique species. Therefore,
we propose that the streets including various habitat types
may thereby create biodiverse urban streetscapes.