15 results on '"Wai Mun Lum"'
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2. Comparative effects of temperature and salinity on growth of four harmful Chattonella spp. (Raphidophyceae) from tropical Asian waters
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Wai Mun Lum, Setsuko Sakamoto, Koki Yuasa, Kazuya Takahashi, Koyo Kuwata, Taketoshi Kodama, Tomoyo Katayama, Chui Pin Leaw, Po Teen Lim, Kazutaka Takahashi, and Mitsunori Iwataki
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bloom potential ,endemicity ,harmful algae ,adaptive ecology ,algal growth ,Fv/Fm ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
In Asia, four harmful raphidophyte species, Chattonella malayana, C. marina, C. subsalsa, and C. tenuiplastida, coexist in the tropical waters but only C. marina was detected in temperate waters. This occurrence pattern pointed to a potentially distinct ecophysiological niche occupancy and possible species dispersion. The growth physiology of these species isolated from tropical Southeast Asia was investigated using unialgal cultures in ten temperatures (13.0–35.5°C) and five salinities (15–35) to better understand the factors driving their distribution. The highest maximum specific growth rates were observed in C. subsalsa (0.65 ± 0.01 d-1), followed by C. malayana (0.47 ± 0.03 d-1), C. marina (0.45 ± 0.02 d-1), and C. tenuiplastida (0.39 ± 0.01 d-1). Their optimal temperatures were 28.0, 30.5, 25.5, and 30.5°C, respectively, of which C. marina preferred colder water. C. subsalsa exhibited a wider growth temperature range (20.5–35.5°C), followed by C. marina (20.5–30.5°C), C. tenuiplastida (23.0–33.0°C), and C. malayana (25.5–33.0°C). Optimal salinities were similar between C. subsalsa and C. malayana (30), and between C. marina and C. tenuiplastida (25), but C. subsalsa and C. marina exhibited a similar growth salinity range of 15–35, while C. malayana and C. tenuiplastida was 20–35. High values of Fv/Fm were observed in C. subsalsa and C. marina (> 0.5) in all tested conditions, but Fv/Fm of C. malayana and C. tenuiplastida were significantly lower at 20.5°C. All four species achieved a maximum cell density of > 104 cells mL-1 in their optimal conditions. Optimal temperatures in C. subsalsa and C. marina were identical to previous reports. The high adaptability of C. subsalsa in various temperatures and salinities suggests its high competitiveness and bloom potential. The high adaptability of C. marina in colder waters compared to other species likely contributes to its wide distribution in the temperate Asian waters. The narrow temperature window of C. malayana and C. tenuiplastida suggests their endemicity and limited distribution in the tropical waters. This study provides evidence about the occurrences and bloom potential of Chattonella spp. in Asia, but the endemicity versus dispersion issue remains unresolved.
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- 2023
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3. Growth, Toxin Content and Production of Dinophysis Norvegica in Cultured Strains Isolated from Funka Bay (Japan)
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Satoshi Nagai, Leila Basti, Hajime Uchida, Takanori Kuribayashi, Masafumi Natsuike, Sirje Sildever, Natsuko Nakayama, Wai Mun Lum, and Ryuji Matsushima
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diarrhetic shellfish poisoning (DSP) ,Dinophysis norvegica ,Mesodinium rubrum ,Teleaulax amphioxeia ,pectenotoxin-2 (PTX2) ,dinophysistoxin-1 (DTX1) ,Medicine - Abstract
The successful cultivation of Dinophysis norvegica Claparède & Lachmann, 1859, isolated from Japanese coastal waters, is presented in this study, which also includes an examination of its toxin content and production for the first time. Maintaining the strains at a high abundance (>2000 cells per mL−1) for more than 20 months was achieved by feeding them with the ciliate Mesodinium rubrum Lohmann, 1908, along with the addition of the cryptophyte Teleaulax amphioxeia (W.Conrad) D.R.A.Hill, 1992. Toxin production was examined using seven established strains. At the end of the one-month incubation period, the total amounts of pectenotoxin-2 (PTX2) and dinophysistoxin-1 (DTX1) ranged between 132.0 and 375.0 ng per mL−1 (n = 7), and 0.7 and 3.6 ng per mL−1 (n = 3), respectively. Furthermore, only one strain was found to contain a trace level of okadaic acid (OA). Similarly, the cell quota of pectenotoxin-2 (PTX2) and dinophysistoxin-1 (DTX1) ranged from 60.6 to 152.4 pg per cell−1 (n = 7) and 0.5 to 1.2 pg per cell−1 (n = 3), respectively. The results of this study indicate that toxin production in this species is subject to variation depending on the strain. According to the growth experiment, D. norvegica exhibited a long lag phase, as suggested by the slow growth observed during the first 12 days. In the growth experiment, D. norvegica grew very slowly for the first 12 days, suggesting they had a long lag phase. However, after that, they grew exponentially, with a maximum growth rate of 0.56 divisions per day (during Days 24–27), reaching a maximum concentration of 3000 cells per mL−1 at the end of the incubation (Day 36). In the toxin production study, the concentration of DTX1 and PTX2 increased following their vegetative growth, but the toxin production still increased exponentially on Day 36 (1.3 ng per mL−1 and 154.7 ng per mL−1 of DTX1 and PTX2, respectively). The concentration of OA remained below detectable levels (≤0.010 ng per mL−1) during the 36-day incubation period, with the exception of Day 6. This study presents new information on the toxin production and content of D. norvegica, as well as insights into the maintenance and culturing of this species.
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- 2023
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4. A new small thecate dinoflagellate Azadinium anteroporum sp. nov. (Amphidomataceae, Dinophyceae) isolated from the Asian Pacific
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Koyo Kuwata, Wai Mun Lum, Kazuya Takahashi, Garry Benico, Hajime Uchida, Mayu Ozawa, Ryoji Matsushima, Ryuichi Watanabe, Hiroshi Oikawa, Toshiyuki Suzuki, and Mitsunori Iwataki
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Plant Science ,Aquatic Science - Published
- 2023
5. Growth, Toxin Content and Production of Dinophysis norvegica in Cultured Strains Isolated From Japan
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Satoshi Nagai, Leila Basti, Hajime Uchida, Takanori Kuribayashi, Masafumi Natsuike, Sirje Sildever, Natsuko Nakayama, Wai Mun Lum, and Ryuji Matsushima
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This study is the first report of the successful cultivation of Dinophysis norvegica isolated from Japanese coastal waters (7 of 48 isolated cells were established as the clonal cultures, 14.5%) and their toxin content and production. The strains were maintained at relatively high abundance (>2,000 cells mL-1) for more than one year when fed on Mesodinium rubrum with the addition of Teleaulax amphioxeia. At the end of the one-month incubation, the total amounts of pectenotoxin-2 (PTX2), dinophysistoxin-1 (DTX1) and okadaic acid (OA) were 132.0-375.0 ng mL-1 (n = 7), 0.7-3.6 ng mL-1 (n = 3) and trace level OA (n = 1), respectively. Similarly, the cell quota of PTX2 and DTX1 were 60.6-152.4 pg cell-1 (n = 7) and 0.5-1.2 pg cell-1 (n = 3), respectively. These data indicated that toxin production varies depending on the strains in this species. In the growth experiment, D. norvegica grew, but it was very slow first 12 days. However, after that they grew exponentially with the maximum growth rate of 0.56 divisions day-1 (during Day 24-27), reaching a maximum concentration of 3,000 cells mL-1 at the end of incubation (Day 36), suggesting that they have a long lag phase. In the toxin production, OA was not at a detectable level (≤ 0.010 ng mL-1) during the 36 days of incubation except for Day 6. The concentration of DTX1 and PTX2 showed similar patterns as described for vegetative growth, but the toxin production still increased on Day 36 (1.3 ng mL-1 and 154.7 ng mL-1 in DTX1 and PTX2, respectively). The findings of this study provide novel information on the toxin content and production in D. norvegica as well as details on the culturing and maintenance of the species.
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- 2023
6. Toxigenic strains of Azadinium poporum (Amphidomataceae, Dinophyceae) from Japan and Vietnam, with first reports of A. poporum (ribotype A) and A. trinitatum in Asian Pacific
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Wai Mun Lum, Toshiyuki Suzuki, Hiroshi Oikawa, Mayu Ozawa, Dao Viet Ha, Mitsunori Iwataki, Hajime Uchida, Kazuya Takahashi, Nguyen Van Nguyen, and Garry Benico
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Azadinium trinitatum ,biology ,Amphidomataceae ,Azadinium poporum ,Azaspiracid ,Zoology ,Plant Science ,Aquatic Science ,biology.organism_classification ,Agricultural and Biological Sciences (miscellaneous) ,Dinophyceae - Published
- 2021
7. Six marine thecate Heterocapsa (Dinophyceae) from Malaysia, including the description of three novel species and their cytotoxicity potential
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Afiqah Hamilton Hanifah, Sing Tung Teng, Ing Kuo Law, Nursyahida Abdullah, Sheryl Uncha Andrew Chiba, Wai Mun Lum, Urban Tillmann, Po Teen Lim, and Chui Pin Leaw
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Microscopy, Electron, Transmission ,Malaysia ,Dinoflagellida ,Plant Science ,Aquatic Science ,Phylogeny - Abstract
Thirty-four strains of Heterocapsa were established from Malaysian waters and their morphologies were examined by light, scanning, and transmission electron microscopy. Three species, H. bohaiensis, H. huensis, and H. rotundata, and three new species, H. borneoensis sp. nov., H. limii sp. nov., and H. iwatakii sp. nov. were described in this study. The three species were differentiated morphologically by unique characteristics of cell size, shape, displacement of the cingulum, shape and position of nucleus, the number and position of pyrenoids, and body scale ultrastructure. The species delimitations were robustly supported by the molecular data. A light-microscopy-based key to species of Heterocapsa is established, with two major groups, i.e., species with a single pyrenoid, and species with multiple pyrenoids. Bioassays were conducted by exposing Artemia nauplii to Heterocapsa densities of 1-5 × 10
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- 2022
8. Description of two new species Chattonella tenuiplastida sp. nov. and Chattonella malayana sp. nov. (Raphidophyceae) from South China Sea, with a report of wild fish mortality
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Wai Mun Lum, Hong Chang Lim, Winnie Lik Sing Lau, Ing Kuo Law, Sing Tung Teng, Garry Benico, Sandric Chee Yew Leong, Kazuya Takahashi, Haifeng Gu, Thaithaworn Lirdwitayaprasit, Chui Pin Leaw, Po Teen Lim, and Mitsunori Iwataki
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Phylogeography ,Fishes ,Animals ,Plant Science ,Aquatic Science ,DNA, Ribosomal ,Phylogeny ,Stramenopiles - Abstract
Fisheries damage caused by Chattonella red tide has been recorded in Southeast Asia. Molecular studies have clarified the presence of two species, Chattonella marina complex and Chattonella subsalsa in the region, unlike East Asia that had only C. marina complex. To elucidate the phylogeography of Chattonella in Asia, further phylogenetic and morphological examinations were carried out with 33 additional culture strains, including the strains isolated during a bloom of Chattonella sp. (up to 142 cells mL
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- 2022
9. Dactylodinium arachnoides sp. nov. (Borghiellaceae, Dinophyceae): a new marine dinoflagellate with a loop-shaped apical structure complex and tubular membranous extrusomes
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Wai Mun Lum, Mitsunori Iwataki, Haruyoshi Takayama, Garry Benico, and Kazuya Takahashi
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0106 biological sciences ,Trichocyst ,Morphology (linguistics) ,biology ,010604 marine biology & hydrobiology ,Dinoflagellate ,Plant Science ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Borghiellaceae ,Phylogenetics ,Botany ,Molecular phylogenetics ,Arachnoides ,Dinophyceae - Abstract
The morphology and phylogeny of an enigmatic marine dinoflagellate were examined using LM, SEM, TEM, and molecular phylogeny inferred from rDNA. Cells were elliptical with a conical epicone and a h...
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- 2019
10. Morphological variation and phylogeny of Karenia selliformis (Gymnodiniales, Dinophyceae) in an intensive cold-water algal bloom in eastern Hokkaido, Japan
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Mitsunori Iwataki, Wai Mun Lum, Koyo Kuwata, Kazuya Takahashi, Daichi Arima, Takanori Kuribayashi, Yuki Kosaka, Natsuki Hasegawa, Tsuyoshi Watanabe, Tomoyuki Shikata, Tomonori Isada, Tatiana Yu. Orlova, and Setsuko Sakamoto
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Japan ,Harmful Algal Bloom ,Dinoflagellida ,Animals ,Water ,Plant Science ,Aquatic Science ,DNA, Ribosomal ,Phylogeny - Abstract
Harmful algal blooms responsible for mass mortalities of marine organisms have been rare in Hokkaido, northern Japan, although fish-killing blooms have been frequently reported from western Japanese coasts. In September-November 2021, a huge and prolonged cold-water bloom occurred along the Pacific coast of eastern Hokkaido, and was associated with intensive mortalities of sea urchin, fish, octopus, shellfish, etc. In this study, morphology and phylogeny of the dominant and co-occurring unarmored dinoflagellates of the Kareniaceae in the bloom were examined by using light microscopy, scanning electron microscopy and molecular phylogeny inferred from ITS and LSU rDNA (D1-D3) sequences. Morphological observation and molecular phylogeny showed that the dominant species was Karenia selliformis, with co-occurrences of other kareniacean dinoflagellates, Kr. longicanalis, Kr. mikimotoi, Karlodinium sp., Takayama cf. acrotrocha, Takayama tuberculata and Takayama sp. The typical cell forms of Kr. selliformis in the bloom were discoid, dorsoventrally flattened, and 35.3-43.6 (39.4 ± 2.1) µm in length, which was larger than the cell sizes in previous reports. Transparent cells of Kr. selliformis, lacking chloroplasts or having a few shrunken chloroplasts and oil droplets, were also found. Cells of Kr. selliformis showed morphological variation, but the species could be distinguished from other co-occurring Karenia species by the nucleus positioned in the hypocone and chloroplasts numerous (46-105) in number and small (2.9-4.6 µm) in diameter. Cell density of Kr. selliformis exceeding 100 cells mL
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- 2022
11. Thecal tabulation, body scale morphology and phylogeny of Heterocapsa philippinensis sp. nov. (Peridiniales, Dinophyceae) from the Philippines
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Kazuya Takahashi, Mitsunori Iwataki, Aletta T. Yñiguez, Garry Benico, and Wai Mun Lum
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Peridiniales ,Scale (anatomy) ,Morphology (linguistics) ,Basal plate (neural tube) ,Philippines ,Dinoflagellate ,Anatomy ,Biology ,biology.organism_classification ,Microbiology ,DNA, Ribosomal ,Pyrenoid ,Microscopy, Electron, Transmission ,Species Specificity ,Molecular phylogenetics ,Dinoflagellida ,Microscopy, Electron, Scanning ,Phylogeny ,Dinophyceae - Abstract
The thecal tabulation and body scale structure of the marine armoured dinoflagellate Heterocapsa, isolated from Philippines, were examined using LM, SEM and TEM, and its phylogenetic position was inferred from ITS and LSU rDNA sequences. Cells were ovoid and the plate tabulation (Po, cp, X, 5′, 3a, 7′′, 6c, 5s, 5′′′, 2′′′′) was consistent with most Heterocapsa species. The second anterior intercalary plate (2a) had a circular pattern with a thick marginal border free of pores. The nucleus was longitudinally elongated and curved, and located at the dorsal side of the cell. Discoid lobes of brownish chloroplast were peripherally distributed, and a pyrenoid was positioned at the centre. The triradiate body scales, measuring 250–300 nm in diameter, consisted of a roundish basal plate with six radiating ridges, nine peripheral uprights/spines, and three radiating spines. These components were identical to those of H. pseudotriquetra and H. steinii, except for the roundish outline of basal plate. Molecular phylogeny showed that the species clustered with H. pseudotriquetra and H. steinii. This species was differentiated from all other Heterocapsa species in the sausage-shaped nucleus and circular pattern on the 2a plate. This study proposed a novel species Heterocapsa philippinensis sp. nov. for the isolate.
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- 2021
12. Comparison of mental-physical comorbidity, risk of death and mortality among patients with mental disorders - a retrospective cohort study
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Alvin Wai Mun Lum, Darren Ee Jin Seah, Eng Sing Lee, Matthias Paul Han Sim Toh, Khai Pang Leong, Phern-Chern Tor, Xiao Wei Tan, Christopher Yi Wen Chan, Daniel Fung, Lee Kong Chian School of Medicine (LKCMedicine), National Healthcare Group Polyclinics, Institute of Mental Health, and Duke-NUS Graduate Medical School
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medicine.medical_specialty ,Bipolar Disorder ,Substance-Related Disorders ,Comorbidity ,Alcohol use disorder ,Internal medicine ,mental disorders ,Humans ,Medicine ,Medicine [Science] ,Bipolar disorder ,Biological Psychiatry ,Depression (differential diagnoses) ,Retrospective Studies ,business.industry ,Mortality rate ,Mental Disorders ,Hazard ratio ,Odds ratio ,medicine.disease ,Psychiatry and Mental health ,Chronic Physical Illness ,Anxiety ,medicine.symptom ,business - Abstract
Aim To compare the risk of death, the prevalence of comorbid chronic physical illness and mortality among an Asian population of patients with mental disorders. Methods This was a retrospective data analysing of medical records of patients with schizophrenia, depression, anxiety, bipolar disorder, alcohol use disorder (AUD) or substance use disorder and the comorbid chronic physical illnesses. The hazard risk of death was calculated with Cox regression and compared between patients with and without comorbid chronic physical illness(es). Odds ratios of specific comorbid chronic physical illness were calculated with logistic regression and mean crude death rate was calculated for patients with different mental disorders. Results A total of 56,447 patients with mental disorders were included in the analysis. Compared to patients without comorbid physical illness, patients with mental-physical comorbidity were associated with a higher risk of death [2.36 (2.22–2.52); hazard ratio (95% CI)] and less estimated survival days [2157 (2142–2172) vs 2508 (2504–2513)]. Compared to other mental disorders, those with AUD had the highest prevalence of two or more comorbid chronic physical illnesses and associated with the highest odds of comorbid hypertension, diabetes mellitus, stroke, nephritis, chronic kidney disease, and cancer. The highest one-year crude death rate was similarly observed in patients with AUD. Conclusions Mental-physical comorbidity was associated with a higher risk of death compared to patients with mental disorders only. The highest prevalence of mental-physical comorbidity and mortality were observed in patients with AUD. More attention and resources may be needed to tackle the burden of AUD.
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- 2021
13. The Harmful Unarmored Dinoflagellate Karlodinium in Japan and Philippines, with Reference to Ultrastructure and Micropredation of Karlodinium azanzae sp. nov. (Kareniaceae, Dinophyceae)
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Wai Mun Lum, Aletta T. Yñiguez, Kazuya Takahashi, Garry Benico, and Mitsunori Iwataki
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0106 biological sciences ,010604 marine biology & hydrobiology ,Peduncle (anatomy) ,Philippines ,Dinoflagellate ,Plant Science ,Aquatic Science ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,DNA, Ribosomal ,Pyrenoid ,Japan ,Genus ,Molecular phylogenetics ,Botany ,Ultrastructure ,Dinoflagellida ,Karlodinium ,Phylogeny ,Dinophyceae - Abstract
In all, 26 cultures of the harmful marine dinoflagellate Karlodinium, isolated from Japanese and Philippine coastal waters, were examined using LM, SEM, and molecular phylogeny inferred from ITS and LSU rDNA. Seven Karlodinium species (six from Japan and four from Philippines), K. australe, K. ballantinum, K. decipiens, K. gentienii, K. veneficum, K. zhouanum, and a novel species Karlodinium azanzae sp. nov., were identified based on their morphology and phylogenetic positions. Karlodinium azanzae from Manila Bay, Philippines was further characterized by TEM, HPLC (chloroplast pigment), and bioassay on brine shrimp and other marine zooplankton. Cells of K. azanzae were the largest (mean 25.3 µm long) in Karlodinium, possessed numerous tiny reflective particles, starch grains, and lipid granules, and usually swam at the bottom of the culture vessel. The straight apical structure complex and a ventral pore were common to the genus. The longitudinally elongated nucleus was located at the center, and the yellowish chloroplasts contained an embedded pyrenoid and carotenoid pigments typical of the genus (i.e., fucoxanthin as major carotenoid with its derivatives). TEM revealed a part of the flagellar apparatus, of which the long striated ventral connective is the first report in the Kareniaceae. Phylogenetic trees showed closest affinity of K. azanzae with K. australe and K. armiger. The new species could be differentiated from related species by cell size, position of the nucleus, and characteristic swimming behavior. Lethality of K. azanzae to large zooplankton and micropredation using a developed peduncle was also observed.
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- 2019
14. The harmful raphidophyte Chattonella (Raphidophyceae) in Western Pacific: Its red tides and associated fisheries damage over the past 50 years (1969–2019)
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Weol Ae Lim, Arief Rachman, Elsa F. Furio, Nguyen Van Nguyen, Thaithaworn Lirdwitayaprasit, Mitsunori Iwataki, Tatiana Yu. Orlova, Wai Mun Lum, Kazumi Wakita, Sing Tung Teng, Hikmah Thoha, Setsuko Sakamoto, Garry Benico, Hai Doan-Nhu, Aletta T. Yñiguez, Sandric Chee Yew Leong, Songhui Lu, Muawanah, Kazuya Takahashi, Chui Pin Leaw, Pengbin Wang, and Po Teen Lim
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biology ,Chattonella ,Harmful Algal Bloom ,Philippines ,Red tide ,Fish farming ,Fisheries ,Plant Science ,Aquatic Science ,Raphidophyte ,Southeast asian ,biology.organism_classification ,Shrimp ,Fishery ,Geography ,Animals ,East Asia ,China ,Asia, Southeastern ,Stramenopiles - Abstract
Red tides and associated fisheries damage caused by the harmful raphidophyte Chattonella were reassessed based on the documented local records for 50 years to understand the distribution and economic impacts of the harmful species in the Western Pacific. Blooms of Chattonella with fisheries damage have been recorded in East Asia since 1969, whereas they have been only recorded in Southeast Asia since the 1980s. Occurrences of Chattonella have been documented from six Southeast Asian countries, Indonesia, Malaysia, Philippines, Singapore, Thailand and Viet Nam, with mass mortalities mainly of farmed shrimp in 1980–1990s, and farmed fish in 2000–2010s. These occurrences have been reported with the names of C. antiqua, C. marina, C. ovata, C. subsalsa and Chattonella sp., owing to the difficulty of microscopic species identification, and many were not supported with molecular data. To determine the distribution of C. marina complex and C. subsalsa in Southeast Asia, molecular phylogeny and microscopic observation were also carried out for cultures obtained from Indonesia, Malaysia, Japan, Philippines, Russia, Singapore and Thailand. The results revealed that only the genotype of C. marina complex has been detected from East Asia (China, Japan, Korea and Russia), whereas both C. marina complex (Indonesia and Malaysia) and C. subsalsa (Philippines, Singapore and Thailand) were found in Southeast Asia. Ejection of mucocysts has been recognized as a diagnostic character of C. subsalsa, but it was also observed in our cultures of C. marina isolated from Indonesia, Malaysia, Japan, and Russia. Meanwhile, the co-occurrences of the two harmful Chattonella species in Southeast Asia, which are difficult to distinguish solely based on their morphology, suggest the importance of molecular identification of Chattonella genotypes for further understanding of their distribution and negative impacts.
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- 2021
15. Gertia stigmatica gen. et sp. nov. (Kareniaceae, Dinophyceae), a New Marine Unarmored Dinoflagellate Possessing the Peridinin-type Chloroplast with an Eyespot
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Mitsunori Iwataki, Kazuya Takahashi, Wai Mun Lum, and Garry Benico
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0301 basic medicine ,Aquatic Organisms ,Chloroplasts ,biology ,Dinoflagellate ,food and beverages ,030108 mycology & parasitology ,biology.organism_classification ,Microbiology ,Carotenoids ,Pyrenoid ,Chloroplast ,Karenia ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Peridinin ,chemistry ,Species Specificity ,Botany ,Dinoflagellida ,Eyespot ,Karlodinium ,Dinophyceae - Abstract
Marine unarmored dinoflagellates in the family Kareniaceae are known to possess chloroplasts of haptophyte origin, which contain fucoxanthin and its derivatives as major carotenoids, and lack peridinin. In the present study, the first species with the peridinin-type chloroplast in this family, Gertia stigmatica gen. et sp. nov., is described on the basis of ultrastructure, photosynthetic pigment composition, and molecular phylogeny inferred from nucleus- and chloroplast-encoded genes. Cells of G. stigmatica were small and harboring a chloroplast with an eyespot and two pyrenoids. The apical structure complex was straight, similar to Karenia and Karlodinium. Under transmission electron microscopy, the chloroplast was surrounded by two membranes, and the eyespot was composed of a single layer of osmiophilic globules (eyespot type A); this was never previously reported from the Kareniaceae. High performance liquid chromatography demonstrated the chloroplast contains peridinin, and neither fucoxanthin nor 19'-acyloxyfucoxanthins was identified. A phylogeny based on nucleus-encoded rDNAs suggested a position of G. stigmatica in the Kareniaceae, but not clustered within the previously described genera, i.e., Karenia, Karlodinium and Takayama. A phylogeny of chloroplast-encoded psbA, psbC and psbD indicated the chloroplast is of peridinin-type typical of dinoflagellates, but the most related species remains unclear.
- Published
- 2019
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