menu.header.image.unacom.logo
 

National Committee on Marine Sciences (NCMS)

Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/6

Browse

Filters

2021 - 20223

Settings

AGROVOC Keyword: search.filters.agrovoc.morphologyAuthor: search.filters.author.Benico, Garry

Search Results

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Characterization of Alexandrium tamutum (Dinophyceae) isolated from Philippine waters, with the rare detection of paralytic shellfish toxin
    Benico, Garry; Azanza, Rhodora (Association of Systematic Biologists of the Philippines, 2022-04-01)
    Alexandrium tamutum M.Montressor, A.Beran & U.John is a non-toxic, bloom-forming dinoflagellate species commonly reported in temperate waters. In this study, 8 cultures of A. tamutum established from Bolinao Channel and Manila Bay, Philippines were characterized in terms of their morphology, phylogeny and toxicity. Cells were roundish, measuring 25.5 –29.84 µm long and 26.2–28.45 µm wide. The nucleus is equatorially elongated and located at the center of the cell. The chloroplasts are numerous, golden brown in color and radially arranged. Thecal tabulation is typical of Alexandrium: APC, 4', 6'', 6c, 6s, 5''', 2''''. Shape of the taxonomically informative thecal plates such as sixth precingular plate (6'') and posterior sulcal plate (sp) was similar to A. tamutum, which confirms the species identity. However, the presence of anterior and posterior attachment pores observed in our cultured isolates is the first case in this species. Molecular phylogeny inferred from LSU rDNA and ITS supports our identification by forming a well-supported clade composed of A. tamutum strains from other geographic regions. HPLC analysis showed that A. tamutum is generally non-toxic except for strain ATC9 which has low amount of decarbamoylsaxitoxin (dcSTX), resulting to a toxicity of 0.07 fmole STX eq per cell. The present study reports the first verified occurrence of Philippine A. tamutum with reliable morphological and molecular information, including the first record in Manila Bay and first detection of PST in one strain at a certain culture period.
    We acknowledge the Department of Science and Technology Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (DOST PCAARRD) and the University of the Philippines-The Marine Science Institute (UP-MSI) for the funding support. We are grateful for the assistance of Joshua Vacarizas, Keith Pinto and Jenelyn Mendoza for the molecular and toxicity analyses of the cultures. We also acknowledge Estrelita Flores, Emelita Eugenio and Jayson Orpeza for their assistance during the fieldwork and other logistical support.
  • No Thumbnail Available
    The harmful raphidophyte Chattonella (Raphidophyceae) in Western Pacific: Its red tides and associated fisheries damage over the past 50 years (1969–2019)
    Lum, Wai Mun; Benico, Garry; Doan-Nhu, Hai; Furio, Elsa; Leaw, Chui Pin; Leong, Sandric Chee Yew; Lim, Po Teen; Lim, Weol Ae; Lirdwitayaprasit, Thaithaworn; Lu, Songhui; Nguyen, Nguyen Van; Orlova, Tatiana Yu.; Rachman, Arief; Sakamoto, Setsuko; Takahashi, Kazuya; Teng, Sing Tung; Thoha, Hikmah; Wang, Pengbin; Yñiguez, Aletta T.; Wakita, Kazumi; Iwataki, Mitsunori (Elsevier, 2021-07)
    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.
    We thank Drs Yuuki Kosaka, Winnie Lik Sing Lau, Ing Kuo Law and Toh Hii Tan for their sampling assistances. We thank Dr. Sadaaki Yoshimatsu for providing a culture strain TAI-93, and Drs Mineo Yamaguchi and Haruo Yamaguchi for support on maintenance and rDNA analysis of the culture. This work was carried out under international collaboration of the IOC/WESTPAC-HAB project and Core-to-Core Program (B. Asia-Africa Science Platforms) of the Japan Society for the Promotion of Science (JSPS). This work was partially supported by Japanese JSPS Kakenhi 19H03027 and 19KK0160 (MI), Malaysian MOHE HICOE IOES and FRGS (PTL), Vietnamese VAST NVCC17.02/21-21 (HD-N), and the Japanese Fund-in-Trust (MEXT).
  • No Thumbnail Available
    Thecal tabulation, body scale morphology and phylogeny of Heterocapsa philippinensis sp. nov. (Peridiniales, Dinophyceae) from the Philippines
    Benico, Garry; Lum, Wai Mun; Takahashi, Kazuya; Yñiguez, Aletta T.; Iwataki, Mitsunori (Elsevier, 2021-08)
    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.