[in Japanese]

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The Japanese Society of Applied Phycology proudly announces the relaunch of its journal as Algal Science and Technology, reflecting the growing diversification of modern algal research. Formerly Algal Resources, the journal now embraces broader perspectives, ranging from molecular biology to social and cultural studies. Contemporary science increasingly emphasizes inter- disciplinary approaches that integrate basic research, applied innovation, and societal implementation̶an approach exemplified by Pasteur’s Quadrant. These trends are highly relevant to algal studies, which address a wide array of issues including climate change, resource sustainability, food systems, and cultural heritage. The renewed journal invites contributions not only from the natural sciences but also from the humanities and social sciences, recognizing that comprehensive understanding and impactful application require diverse academic perspectives. Newly established article categories and an improved layout further support this inclusive editorial vision. We warmly welcome submissions from researchers across disciplines and look forward to developing a dynamic platform that fosters innovation, integration, and communication in the field of phycology.

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The primary regulatory step in responses to environmental stresses and plant hormones is transcription, in which transcription factors play key roles in regulating gene expression induced by internal and external stimuli. Advances in genome and transcriptome analyses of the marine red alga Pyropia yezoensis and ‘Bangia’ sp. ESS1 represented the presence of various kinds of transcription factors in Bangiales. However, these organisms lack most plant-specific transcription factors, such as DREB, NAC, WRKY, and DOF, all of which are involved in environmental stress-inducible transcription in terrestrial plants. Additionally, transcription factors regulating plant hormone-inducible transcription, such as ARF, ABI3, Aux/IAA, NPR, ERF, and BZR1/BES1, are absent in Bangiales, despite the presence of auxin and salicylic acid in P. yezoensis and ‘Bangia’ sp. ESS1. These findings indicate that the responses to environmental stresses and plant hormones in Bangiales are regulated by unidentified transcription factors that are not found in terrestrial plants. Therefore, identifying Bangiales-specific transcription factors involved in stress and hormone responses provides novel insights into both the survival strategies of Bangiales and the diversity of stress- and hormone-inducible transcription based on the differences in transcription factors among photosynthetic organisms.

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Carbon dioxide (CO₂) fixation in aqueous environments presents a major challenge for photosynthetic organisms due to slow CO₂ diffusion rates and the low affinity of CO₂-fixing enzyme Rubisco for CO₂. Algae have evolved CO₂-concentrating mechanisms (CCMs) centered around a specialized non-membrane-bound organelle called the pyrenoid, which concentrates Rubisco through liquid-liquid phase separation. The pyrenoid architecture comprises three key features: a Rubisco-rich matrix formed through phase separation with the linker protein EPYC1, a surrounding starch sheath that acts as a CO₂ diffusion barrier, and specialized pyrenoid tubules that facilitate CO₂ delivery. Recent studies using the model green alga, Chlamydomonas reinhardtii, have revealed that pyrenoid assembly and maintenance are regulated by complex molecular mechanisms, including multivalent protein interactions, dynamic protein relocalization, and calcium-dependent signaling pathways. Environmental CO₂ levels trigger distinct carbon uptake pathways that are energized by photosynthetic and mitochondrial electron transport. Engineering efforts to introduce pyrenoid-based CCMs into crops have made significant progress, with successful reconstitution of matrix formation, starch recruitment, and thylakoid membrane extensions in plant chloroplasts. These advances provide new opportunities for improving crop photosynthetic efficiency while offering insights into phase separation-driven organelle assembly.

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Marine diatom is a eukaryotic alga fixing 20 % of global CO₂. This massive productivity is sustained by their uniquely structured secondary chloroplast. Diatom chloroplasts possess layered thylakoid membranes, comprising of the outer-most girdle lamellae and the inner stroma thylakoid (ST). At the central chloroplast, there is pyrenoid, which is a phase-separated Rubisco condensate interlinked by intrinsically disordered proteins. In diatoms, protein called Pyrenoid Shell (PyShell) shapes and covers the pyrenoid, within which thylakoid traverses along the axis of the pyrenoid core, that is, pyrenoid-penetrating thylakoid (PPT). The PPT lumen specifically harborsθ-type carbonic anhydrase (CA) and the genome editing disruption of this luminalθ-CA re- sulted in a null CCM phenotype, indicating the pivotal role of PPT luminalθ-CA to constitute the “CO₂-evolving machinery” for Rubisco in the pyrenoid. The HCO₃^- supplier for the CO₂-evolving machinery is bestrophin (BST) family protein, localized at the ST and/or PPT area. The KO of ST-type PtBST1 suppressed CCM to the level mimicking high CO₂ acclimated cells and moderately enhanced NPQ, suggesting that ST-type BST enhances CO₂ fixation for CCM, thus thylakoidal linear electron flow, in sacrifice of NPQ. These results indicate that the CO₂-evolving machinery in the pyrenoid coordinates CO₂ and light utilization efficiency.

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To obtain crops effectively for bioethanol production, conventional agriculture uses artificial chemical agents, such as fertilizers, insecticides, and herbicides. Bioethanol contributes to the carbon-neutral strategy; however, ecosystems are affected by these chemicals in agriculture. In a previous study, we reported the development of a yeast strain that can convert macroalgae into ethanol. Because macroalgae have a higher ability to fix CO₂ than terrestrial plants, we aimed to obtain large amounts of macroalgae. Herein, we propose a novel cultivation system for macroalgae using newly developed equipment and methods. Additionally, applicable yeast strains constructed using surface display technology for bioethanol production using living macroalgae are described.

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In marine ecosystems, many macroalgae grow faster than terrestrial plants. Brown algae among macroalgae are considered to be a source of physiologically active substances such as polyphenols. Further, as the first finding, some macroalgae can capture more carbon dioxide from the atmosphere than plants. Macroalgae had emerged as a biomass feedstock for bioethanol production owing to their low liginin content and applicability to biorefinery processes. We are challenging the bioconversion of macroalgae into bioactive substances and biofuels using microbial biotechnology, including engineered yeast design using synthetic biological technology.

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With the increasing focus on carbon neutrality, the development of biorefinery technologies has garnered considerable attention. Macroalgae offer potential advantages as biorefinery feedstocks over terrestrial plants and microalgae that have been studied to date, due to their lack of recalcitrant lignin and potentially lower cultivation costs. Sargassum muticum discovered in Fukuoka City, Fukuoka Prefecture, exhibited a maximum average thallus length of 397 cm, exceeding previously reported values, with a maximum individual length of 536 cm observed. The growth density was also higher than previously reported, with an average of 123 ind./m² and a maximum of 166 ind./m². Based on thallus length and growth density data obtained from the natural environment, a carbon dioxide fixation capacity of 25,382.8 g/m² under high-density cultivation was estimated. Component analysis revealed a carbohydrate content of 50.4 ％, with an estimated potential ethanol production of 5,146 g/m². These results indicate the promising potential of S. muticum as a feedstock for macroalgal biorefinery.

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Fucoidan, a sulfated fucose-containing polysaccharides derived from brown algae such as Gagome kombu Kjellmaniella crassifolia, has been shown to contribute to immune modulation and health maintenance. In 2023, we preliminarily reported that ingesting foods containing fucoidan derived from Gagome kombu is beneficial for improving physical condition and maintaining immunity in healthy people. And now, all analyses of the study have been completed. In this paper, we report on the evaluation of the cumulative number of days with cold-like symptoms for the evidence improvement in overall physical condition. A randomized, double-blind, placebo-controlled, parallel group study was conducted. After a 12-week intake period, it was confirmed that most subjective symptoms, including throat pain, nasal discharge, nasal congestion, cough, and fatigue ̶ but excluding joint pain and headache ̶ showed statistically significant improvement in the Gagome kombu fucoidan intake group compared to the placebo group (p<0.05). These results indicated that Gagome kombu fucoidan intake maintains immune function in a normal state and is effective in maintaining a healthy state in response to changes in overall physical condition.

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The cultivation yield of Undaria pinnatifida (wakame) in the Sanriku region, which stretches from Iwate Prefecture to Miyagi Prefecture, the central wakame production area in Japan, has been declining. We investigated wakame cultivation off the coast of Yuriage in southern Miyagi Prefecture, aiming to develop a new cultivation area that meets high market demand. In the first season, three regional strains were cultivated, observing growth characteristics that differed from those in the conventional cultivation areas in Miyagi Prefecture. During the second season, two strains were grown and reached harvest without damage to cultivation facilities by wave motion, 8.9 tonnes of raw material was harvested from March to May, and 1,935 kg of boiled and salted wakame was produced and sold. The thickness of the blades reached a level comparable to that of other major cultivation areas in the Sanriku region. In conclusion, the environmental conditions along the Yuriage coast are suitable for wakame cultivation on a practical scale. This development could contribute to the stability of the local fisheries and increase income for fishers off the Yuriage coast.

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Suminori refers to dried nori, low for its taste, texture and unglossy. During the drying process, nori thalli are immersed in freshwater, leading to water absorption by their cells. This results in the agglutination of protoplasm and the subsequent its discharge, causing the nori to lose its glossy appearance and take on a dull, unglossy look similar to ink staining. This symptom has been reported as a bacterial disease and a physiological disease of unknown cause. The present study demonstrates that protoplasm discharge is induced under conditions of darkness, high-density cultivation, and anaerobic (low-oxygen) environments, with the extent of discharge increasing over time. These observations experimentally confirm that anaerobic conditions in the cultured seawater are a significant contributing factor to Suminori appearance. This study provides evidence that the application of UFB seawater (ultra fine bubble seawater) containing dissolved oxygen can suppress discharge of protoplasm while activating nori thalli. Furthermore, introducing UFB seawater with oxygen during the manufacturing process effectively mitigates protoplasm discharge, presenting a practical countermeasure to address Suminori appearance and improve the quality of dried nori.

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This paper examines the production and distribution of Nori (laver) from the mid-Modern period to the end of the Edo Restoration period, mainly in the coastal area of Ebara County near the southern part of Edo (Tokyo) - Shinagawa to Omori - which is considered to be the birthplace of Asakusa Nori, while looking at the proposition of “Nori studies” based on a fusion of the humanities and sciences. This study examines the actual situation regarding the production and distribution of Nori (laver) from the mid-Modern period to the end of the Edo period. Here, we take up the production and distribution of Nori in relation to the characteristics of the socio=spatial structure (zonal structure) in the relevant zones. We will then examine: (1) the Nori Hibi (Nori farm sites) in the waterfront area since the mid-18th century, (2) the rapid expansion of Nori production through the first half of the 19th century, and (3) the relationship between the Edo Nori wholesalers and other Nori merchants who led these efforts and Omori, Shinagawa, and other newly emerging Nori production areas.

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The production and consumption of seaweed laver have historically been concentrated in Japan, South Korea, and China. Over time, the global spread of Japanese food culture with “Nori”, combined with the development of new products such as snack laver, has driven its consumption to expand globally. As of 2019, the global laver export market reached $770 million which was $450 million in 2015. East Asia remains the largest market, accounting for $380 million, while North America and Southeast Asia each represent $150 million, and Europe accounts for $60 million.
South Korea has emerged as a major player in the international laver market, contributing approximately 75 % of the global export volume as of 2019. This reflects a substantial increase from $60 million in exports in 2007 to $580 million in 2019. Key drivers of this growth include mass production systems separating aquaculture and processing, active market expansion, and product innovation. While South Korea previously depended on Japan for technologies and equipment, it has developed self-sufficient production and processing capabilities. Despite intensified competition with foreign companies for the acquisition of raw materials, South Korea continues to adapt to the evolving demands of global markets, solidifying its position as a leading exporter in the international laver industry.

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This study explores the restructuring of Japan’s nori distribution system through a two-part analysis. The present first part focuses on the structure and limitations of the “production-dependent” distribution model, centered on the kyohan (joint marketing) system. While this model has long contributed to price stability and uniform product quality, recent production declines, environmental instability, and shifts in consumer behavior have revealed increasing institutional fatigue. In particular, instability in the Ariake Sea highlights the model’s vulnerability and the urgent need for institutional reform. By analyzing production trends, the design and operation of the kyohan system, and consumption patterns across generations, the paper demonstrates how the current framework struggles to meet the demands of today’s market.
The forthcoming second part will examine the proposed “relationship-dependent” model as an alternative, drawing on the concept of value co-creation. It will analyze theoretical foundations and practical cases to suggest how relational mechanisms can complement the existing institutional system and promote sustainable distribution.

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Miru Monyo – pattern (海松文様) is a uniquely Japanese design that resembles a seaweed Miru (Codium fragile (Suringar) Hariot). Miru is a common seaweed that is distributed widely along the coasts of the Japanese archipelago, and has been used as food, sacred offerings, and herbal medicine since ancient times.
In particular, Miru with anthelmintic properties may have been a symbol of protection from disease and disaster, and Miru Monyo depicting Miru has been painted on kimonos, furnishings and other items.
In addition, Miru forms self-similar symmetries (the whole and the parts have the same shape), and shows the Golden Ratio (1.61), which people find beautiful. In other words, Miru Monyo was born and inherited from the culture derived from the medicinal effects of Miru among the Japanese and the morphological beauty of Miru itself. It embodies a part of Japanese culture where the Japanese have deepened their aesthetic sense through empathy and engagement with nature.

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Pyropia tenera is an endangered species in Japan. In Miyagi prefecture, its inhabitation had been confirmed at Torinoumi Lagoon, Mangoku-ura Bay, Nagatsura Lagoon, Ido-ura Lagoon, and the mouth of Omosegawa River before the great east Japan earthquake in 2011. However, Torinoumi and Mangoku-uea Lagoons are only localities for re-confirmation of the inhabitation of P. tenera after 2011. Thus, in the present study, we surveyed the current inhabitation of P. tenera at the mouth of Omosegawa River as well as Torinoumi Lagoon. We first collected Bnagiales from these localities and then species of these samples was identified by homology search using the DDBJ/EMBL/GenBank database based on DNA sequence information of their plastid-genome-encoded RuBisCO large subunit gene (rbc L) and restriction fragment length polymorphism analysis for two nuclear genes encoding type II DNA polymerase and actine-related protein 4. As results, all Bangiales collected and analyzed were P. tenera, indicting the presence of P. tenera at two localities after the great east Japan earthquake. In addition, phylogenetic analysis using rbc L sequences represented the less genetic diversity in P. tenera population from Miyagi prefecture, which contrasts with genetic diversity of those from Kumamoto prefecture. Although it is unclear a reason for the place-dependent difference in genetic diversity, contribution is required for conservation and protection of biodiversity in P. tenera strains from different localities throughout Japan.

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