Kajita Tadashi

写真a

Title

Professor

Researcher Number(JSPS Kakenhi)

80301117

Homepage URL

http://nesseiken.info

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Current Affiliation Organization 【 display / non-display 】

  • Concurrently   University of the Ryukyus   Graduate School of Agriculture   Professor  

  • Concurrently   University of the Ryukyus   The United Graduate School of Agricultural Sciences, Kagoshima University   Professor  

  • Duty   University of the Ryukyus   Tropical Biosphere Research Center   Professor  

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University 【 display / non-display 】

  • 　
    -
    1989

    Tohoku University   Faculty of Science   Graduated

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Graduate School 【 display / non-display 】

  • 　
    -
    1991.03

    Tohoku University  Graduate School, Division of Natural Science  Doctor's Course (first term)  Completed

  • 　
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    1994.03

    Tohoku University  Graduate School, Division of Natural Science  Doctor's Course (second term)  Completed

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External Career 【 display / non-display 】

  • 2015.05
    　
    　

    University of the Ryukyus, Tropical Biosphere Research Center, Professor  

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Research Interests 【 display / non-display 】

  • 分子系統学

  • 保全生物学

  • マングローブ

  • マメ科

  • Sea-dispersal

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Research Areas 【 display / non-display 】

  • Life Science / Biodiversity and systematics

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Published Papers 【 display / non-display 】

  • Application of eDNA metabarcoding in the assessment of fish biodiversity in Philippine mangroves: Challenges and opportunities

    Camila Frances P. Naputo, Yukinobu Isowa, Maria Elisa Gerona-Daga, Ma Daniela Artigas, Tadashi Kajita, Severino G. Salmo

    Regional Studies in Marine Science   77   2024.12 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Biodiversity assessments are important in designing mangrove conservation and restoration programs. In the Philippines, conventional biodiversity assessment methods (e.g., trap nets, fish visual census) can be time-consuming, labor-intensive, and expensive. In recent years, environmental DNA (eDNA) metabarcoding has been an emerging tool for rapid biodiversity monitoring as it is fast, non-intrusive, and can provide broader detection of fauna. But, it is still subject to various field sampling and laboratory analysis constraints. Here, we applied the eDNA metabarcoding method to document and assess fish biodiversity in mangroves from two biogeographic regions in the Philippines: Oriental Mindoro in the West Philippine Sea and Sorsogon in the Northern Philippine Sea. Using 12S genetic markers from eDNA water samples, we detected 89 fish species from 44 families. Only twelve species were commonly detected in both sites. Several species were found in the Philippines' list of economically important aquatic organisms while one species (Epinephelus fuscoguttatus) was classified as Vulnerable in IUCN's Red List of Threatened Species. Seventy-six percent more species were detected in Sorsogon probably because the sampling sites were within a seascape of mangroves, seagrasses, and coral reefs. In contrast, the lesser species detected in Oriental Mindoro could probably be because of the more limited sampling points to coastal fringes. Our results serve as baseline data and the first obtained using this method in the country. However, we observed some limitations that should be addressed to improve the method: (1) lack or absence of a comprehensive reference database specific to Philippine aquatic organisms; (2) low eDNA reads which could be attributed to insufficient on-site filtration due to turbid seawaters common in Philippine mangroves; and (3) possible cross-contaminations that can affect comparative analyses. Despite these limitations, we were able to demonstrate the usefulness of this technique in doing rapid assessments which could address knowledge gaps in Philippine mangrove biodiversity studies and contribute to its conservation programs.

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  • Diversity and distribution of nitrifying bacteria play an important role in the nitrogen cycle in mangrove sediments

    A. Mubaraq, M. Sembiring, E. Widiastuti, E. Fachrial, B. Utomo, M. Turjaman, F. Sidik, Y. I. Ulumuddin, V. B. Arifanti, E. S. Siregar, T. Kajita, Procheş, M. Basyuni

    Global Journal of Environmental Science and Management   10 ( 4 ) 2145 - 2162   2024.09 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    The unique positioning of mangrove ecosystems between land and sea makes them vital in the nitrogen cycle. The role of nitrification in the nitrogen cycle is important to provide nitrogen compounds readily absorbed by mangrove plants. Nevertheless, the nitrification process and nitrifying bacteria in mangrove areas have yet to be comprehensively understood. The primary objective of this study is to provide comprehensive analysis of nitrifying bacteria in mangrove sediments by conducting a systematic review. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method is used as a guide to help report reviews systematically and has a flow chart to show the process of selecting relevant studies. Data collection was carried out by utilizing 6 databases and journal search engines including Scopus, PubMed, ResearchGate, Google Scholar, and Springer in order to achieve more comprehensive findings. This study employed the widely recognized and commonly used technique of defining the review's scope in a focused manner by first identifying the population, intervention, comparison, and outcome. This study identified 358 studies, and 31 studies were included in the review after screening. Based on the screening results, research on nitrifying bacteria in mangrove sediments is geographically limited to several countries such as Indonesia, Vietnam, Thailand, China, Mexico, the United States, India, and Saudi Arabia. This study vealed that there is a high level of diversity among nitrifying bacteria in mangrove sediment, with five distinct groups identified: ammonia oxidizing bacteria, nitrite oxidizing bacteria, anammox bacteria, and comammox bacteria, a recently identified group. In carrying out changes in nitrogen compounds, nitrifying bacteria use functional genes from different steps of the nitrification process, such as nitrogenase, ammonia monooxygenase subunit A, nitrite oxidoreductase alpha subunit, nitrate reductase alpha chain, nitrite reductase, nitric oxide reductase, nitrous oxide reductase, hydrazine synthase, hydrazine oxidoreductase and hydroxylamine oxidoreductase genes. Ammonia-oxidizing bacteria were the predominant group in general, but various nitrifying bacteria groups were distributed diversely across different mangrove environments. This study also indicated the vegetation type and the distribution of nitrifying bacteria in mangrove sediments. The depth of these sediments typically varies from 0 to 60 centimeters, with most samples taken at a depth of 0 to 20 centimeters. The type of vegetation at the sampling location is dominated by species of Kandelia candel, Avicennia marina, Kandelia obovata, and Rhizophora mangle. Limitations regarding research on nitrifying bacteria in mangrove sediments provide opportunities for in-depth study. This comprehensive review provides an in-depth overview of the variety and spread of nitrifying bacteria, highlighting their role in nitrogen cycling and emphasizing the potential for discovering new nitrifying bacteria in mangrove sediments.

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  • Current biodiversity status, distribution, and prospects of seaweed in Indonesia: A systematic review

    Mohammad Basyuni, Maya Puspita, Rinny Rahmania, Hatim Albasri, Indra Pratama, Dini Purbani, A. A. Aznawi, Alfian Mubaraq, Shofiyah S. Al Mustaniroh, Firman Menne, Yulizar Ihrami Rahmila, Severino G. Salmo, Arida Susilowati, Siti H. Larekeng, Erwin Ardli, Tadashi Kajita

    Heliyon   10 ( 10 )   2024.05 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Seaweeds are a valuable component of marine biodiversity that play multiple essential roles in Indonesia's coastal ecology and economy. This systematic review (1993–2023) aimed to provide an updated overview of seaweed distribution, biodiversity, cultivation, and industry in Indonesia. The literature search derived from major databases, Scopus, Web of Science (WoS) and ResearchGate (RG), and Google Scholar (GS) retrieved 794 studies, after removing 80 duplicates, identified 646 studies passed title and abstract screening that satisfied all criteria: Indonesia, seaweed, seaweed biodiversity and composition, which consisted of 80 exclusion studies. Full text screening decided 194 studies were selected based on the specific inclusion criteria (at least two criteria passed: seaweed distribution site, species, cultivation, and habitat). After additional filtering, 137 studies were included for extraction and analysis. We found that Indonesia is rich in seaweed biodiversity, with at least 325 identified species consisting of 103 Chlorophyceae (green algae), 167 Rhodophyceae (red algae), and 55 Phaeophyceae (brown algae), respectively. Seaweed distribution and abundance in Indonesia are influenced by environmental factors, including nutrients, grazing, competition, physical tolerance, light intensity, and degree of water circulation. Seaweed species are predominantly found in mangrove forests and coral reefs on the islands of Sumatra, Java, Kalimantan, and Sulawesi. This review provides an up-to-date and comprehensive overview of the distribution and biodiversity of seaweeds in Indonesia, highlighting the ecological, economic, and cultivation of marine resources. In addition, we identify knowledge gaps and areas for further research, which can inform sustainable seaweed management and utilization in Indonesia. This review also emphasizes the significance of this marine resource to Indonesia's environment and economy.

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  • Evolutionary and ecological trends in the Neotropical cycad genus Dioon (Zamiaceae): An example of success of evolutionary stasis

    José Said Gutiérrez-Ortega, Miguel Angel Pérez-Farrera, Mitsuhiko P. Sato, Ayumi Matsuo, Yoshihisa Suyama, Andrew P. Vovides, Francisco Molina-Freaner, Tadashi Kajita, Yasuyuki Watano

    Ecological Research ( Wiley )    2024.02 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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  • Mangrove plants using deoxyribonucleic acid barcodes for enhancing biodiversity and conservation

    M. Basyuni, R. Syahbana, A. B. Rangkuti, N. A. Pradisty, A. Susilowati, L. A.M. Siregar, S. S.Al Mustaniroh, A. A. Aznawi, A. Mubaraq, E. R. Ardli, S. H. Larekeng, V. Leopardas, Y. Isowa, T. Kajita

    Global Journal of Environmental Science and Management   10 ( 3 ) 1391 - 1410   2024 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    BACKGROUND AND OBJECTIVES: Mangrove forests in North Sumatra and Aceh are concentrated on the east coast of Sumatra Island. Mangrove habitats are highly productive, diversified, and ecologically and commercially significant ecosystems. However, they are vulnerable to both anthropogenic and natural hazards. The identification of coastal ecosystem species, such as mangrove and coastal forests, is very important in conserving and using the biodiversity of coastal ecosystems, which appears to be hindered by a lack of taxonomic and molecular expertise. This study aimed to address the lack of reference deoxyribonucleic acid barcodes from mangroves in North Sumatra and Aceh and assess the effectiveness of four deoxyribonucleic acid barcoding methods in terms of primer universality, successful identification rate, barcoding gap and species-tree inference, and then phylogenetic tree construction. METHODS: This study focused on selecting the main regions where mangroves are predominantly distributed in the provinces of North Sumatra and Aceh: Percut Sei Tuan and Deli Serdang mangrove areas, Pulau Sembilan and Lubuk Kertang of Langkat mangrove areas in North Sumatra, and Langsa mangrove areas in Aceh. The genomic deoxyribonucleic acid of mangrove plants was isolated from fresh leaf material using the Geneaid genomic deoxyribonucleic acid mini kit. Based on the guidance provided by the International Union for Biological Barcoding with four molecular sequences, deoxyribonucleic acid barcodes were chosen for amplification: chloroplast ribulose 1,5-bisphosphate carboxylase/oxygenase, maturase-K, transfer ribonucleic acid for histidine–photosystem II reaction center protein A, and nuclear genome internal transcribed spacer. The Tamura 3-parameter + Gamma method in molecular evolutionary genetics analysis X software was used to measure and describe the genetic distances between different species and within the same species. The construction of phylogenetic trees was carried out using the molecular evolutionary genetics analysis X from ribulose 1,5-bisphosphate carboxylase/ oxygenase, transfer ribonucleic acid for histidine–photosystem II reaction center protein A, Internal transcribed spacer, and maturase-K barcodes based on the bootstrap analysis conducted using 100 permutations. FINDINGS: This study showed that the primers ribulose 1,5-bisphosphate carboxylase/oxygenase, transfer ribonucleic acid for histidine–photosystem II reaction center protein A, internal transcribed spacer, and maturase-K had the highest success rates during amplification, which could be strong barcodes for enhancing taxonomic clarification and gaining insights into phylogenetic relationships. The primers ribulose 1,5-bisphosphate carboxylase/oxygenase, transfer ribonucleic acid for histidine–photosystem II reaction center protein A, internal transcribed spacer, and maturase-K had the highest success rates during amplification. The success rate for the ribulose 1,5-bisphosphate carboxylase/oxygenase gene was the highest (90% percent), followed by (86 percent), transfer ribonucleic acid for histidine–photosystem II react percent ion center protein Ainternal transcribed spacer (75 percent), and maturase-K (57 Percent). The significant differences were as follows: inter- and intraspecific genetic distance (probability (p) <0.001), maturase-K (probability = 0.0001), combination maturase-K + photosystem II reaction center protein A (probability = 0.0008), maturase-K + ribulose 1,5-bisphosphate carboxylase/oxygenase (probability = 0.0008), maturase-K + internal transcribed spacer (probability = 0.0003), ribulose 1,5-bisphosphate carboxylase/oxygenase + internal transcribed spacer (probability = 0.0002), photosystem II reaction center protein A + internal transcribed spacer (probability = 7.051e-05), and three combined markers maturase-K + photosystem II reaction center protein A + internal transcribed spacer (probability = 0.0007). It is noteworthy that the maturase-K barcode could construct the clustering and differentiate the mangrove species based on family and not from sites. The ribulose 1,5-bisphosphate carboxylase/oxygenase barcode showed that members of Rhizophoraceae (Bruguiera parviflora, Rhizophora apiculata, and Rhizophora stylosa), Ptiredeacea (Acrostichum aureum), and Scyphiphora hydrophyllaceae from Rubiaceae existed in one branch. CONCLUSION: This study provided a reference database both molecularly and taxonomically to strengthen biodiversity assessment and monitor mangrove forests. This database can be used to clarify the results of deoxyribonucleic acid barcodes for morphological and biochemical identification in the eastern coast of Sumatra.

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Other Papers 【 display / non-display 】

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Work 【 display / non-display 】

  • Field works for the study of patropic sea-current seed dispersal plants

    1997
    　
    　
     

  • Phylogegraphical study of pantropic sea-current seed dispersal plants

    1997
    　
    　
     

  • Molecular systematic study of Desmodieae(Leguminosae)

    1994
    　
    　
     

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