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Journal Articles - UP - MSI

Permanent URI for this collectionhttps://repository.unesco.gov.ph/handle/123456789/50

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Author: search.filters.author.Santiañez, Wilfred John E.Ocean Decade Challenge: search.filters.odc.Challenge 2: Protect and restore ecosystems and biodiversity

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    Marine macroalgal reference culture collection at the University of the Philippines Marine Science Institute (UP-MMARCC): Status and prospects for advancing Philippine phycology
    Santiañez, Wilfred John E.; Guerta, Christian Ace T.; Lastimoso, John Michael L. (Assocation of Systematic Biologists in the Philippines, 2022-11-16)
    Seaweeds research in the Philippines-from studies on their diversity, natural products chemistry, and the utilization of their derivatives-is largely based on spot collections of large and conspicuous components of the seaweed flora found along the coasts. Such efforts are often focused on commercially important seaweeds; thus, most of the smaller and even microscopic seaweeds remain understudied, if not completely overlooked. Consequently, little to none is known on many aspects of the biology, ecology, and even biochemistry of these components of the Philippine seaweed flora. To understand aspects of seaweed biology and serve as a facility for preserving the genetic resources of Philippine seaweeds, we established the Marine Macroalgal Reference Culture Collection at the University of the Philippines Marine Science Institute (UP-MMARCC). We are currently maintaining 446 seaweed strains (or isolates) collected from several coastal and offshore areas in the Philippines, the latter including the Kalayaan Island Group in the West Philippine Sea, and 25 isolates from Okinawa, Japan. To our knowledge, the UP-MMARCC is the most diverse and widely sampled culture collection in the Philippines so far. Moreover, our preliminary molecular-assisted biodiversity studies suggest that UP-MMARCC houses several isolates that are either new records to the Philippines or putative new taxa. We anticipate that with continued support, we will be able to sustain and expand our culture collection, not only to facilitate discoveries but also to cater to the needs of the Philippine seaweed industry and in support of its call for diversifying our seaweed commodities and their products.
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    Cryptic haploid stages in the life cycle of Leathesia marina (Chordariaceae, Phaeophyceae) under in vitro culture
    Poza, Ailen M.; Santiañez, Wilfred John E.; Croce, M. Emilia; Gauna, M. Cecilia; Kogame, Kazuhiro; Parodi,Elisa R. (2020-05-28)
    We evaluated the life cycle of Leathesia marina through molecular analyses, culture studies, morphological observations, and ploidy measurements. Macroscopic sporophytes were collected from two localities in Atlantic Patagonia and were cultured under long-day (LD) and short-day (SD) conditions. Molecular identification of the microscopic and macroscopic phases was performed through the cox3 and rbcL genes and the phylogeny was assessed on the basis of single gene and concatenated datasets. Nuclear ploidy of each phase was estimated from the DNA contents of individual nuclei through epifluorescence microscopy and flow cytometry. Molecular results confirmed the identity of the Argentinian specimens as L. marina and revealed their conspecificity with L. marina from New Zealand, Germany, and Japan. The sporophytic macrothalli (2n) released mitospores from plurilocular sporangia, which developed into globular microthalli (2n), morphologically similar to the sporophytes but not in size, constituting a generation of small diploid thalli, with a mean fluorescent nuclei cross-sectional area of 3.21 ± 0.7 μm2. The unilocular sporangia released meiospores that developed two morphologically different types of microthalli: erect branched microthalli (n) with a nuclear area of 1.48 ± 0.07 µm2 that reproduces asexually, and prostrate branched microthalli (n) with a nuclear area of 1.24 ± 0.10 µm2 that reproduces sexually. The prostrate microthalli released gametes in LD conditions, which merged and produced macroscopic thalli with a nuclear cross-sectional area of 3.45 ± 0.09 µm2. Flow cytometry confirmed that the erect and prostrate microthalli were haploid and that the globular microthalli and macrothalli were diploid.
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    Manzaea minuta gen. & comb. nov. (Scytosiphonaceae, Phaeophyceae) from the tropical Northwestern Pacific Ocean
    Santiañez, Wilfred John E.; Kogame, Kazuhiro (Philippine Journal of Systematic Biology, 2022-07-11)
    Recent molecular-assisted taxonomic studies on the brown algal genus Hydroclathrus has resulted in discoveries of new taxa in the family Scytosiphonaceae, both at the genus and species level. However, phylogenetic studies on Hydroclathrus based on wide geographical sampling also suggested that the genus is not monophyletic. That is, one of the recently described species Hydroclathrus minutus is consistently segregated from the Hydroclathrus main clade. We propose here to segregate H. minutus from the brown algal genus Hydroclathrus and establish the new monotypic genus Manzaea (i.e., Manzaea minuta gen. & comb. nov.) based on information on molecular phylogenetics and morpho-anatomy. Morphologically, M. minuta is similar to Hydroclathrus and Tronoella in having clathrate (net-like) and spreading thalli but is differentiated from the latter two genera in having membranous thalli that are sometimes interadhesive resulting in portions of the thallus forming amorphous clumps. Additionally, Manzaea is distinguished from both clathrate genera in having thick-walled medullary cells and short closely arranged quadriseriate plurangia. Phylogenetic analyses (Maximum Likelihood and Bayesian Inference) based on single (plastidial psaA and rbcL genes) and concatenated (cox3 + psaA + rbcL) genes showed that M. minuta is consistently segregated from the highly supported clade of Hydroclathrus species and often clustering with Tronoella and/or Rosenvingea. Our proposal further increases the diversity of monotypic genera in the Scytosiphonaceae and underscores the need to conduct further studies on tropical seaweed biodiversity.
    WJES thanks Dr. Gavino C. Trono, Jr. and Dr. Edna T. Ganzon-Fortes for the inspiration and encouragement to conduct seaweed biodiversity and systematics research. WJES is funded by the University of the Philippines through the Balik PhD Program of the Office of the Vice President for Academic Affairs (OVPAA-BPhD-2018-05), the University of the Philippines Diliman through the In-house research grant of the Marine Science Institute, and the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of the Government of Japan under the Monbukagakusho Scholarship Grant. WJES also acknowledges the support of the Department of Science and Technology (DOST)-Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) of the Government of the Philippines through the DOST Balik Scientist Program.
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    Molecular-assisted taxonomic study on the Sargassum C.Agardh (Fucales, Phaeophyceae) in Northwestern Luzon, Philippines
    Santiañez, Wilfred John E.; Lastimoso, John Michael L.; Hoshino, Masakazu; Villafuerte, Brix Nester Q.; Kogame, Kazuhiro; Trono, Gavino C. (Museum National d'Histoire Naturelle, 2023-10-18)
    The diversity of the brown algal genus Sargassum C.Agardh in the Philippines is the highest in the tropical western Pacific Ocean. However, most studies on Philippine Sargassum are based on morphoanatomies and the assumption that the genus is very diverse in the country has never been tested based on molecular information. Considering that many Sargassum species are highly polymorphic and the recent advance on Sargassum systematics facilitated by molecular phylogenetic studies, we believe that the species of Sargassum from the Philippines should now be reassessed with the tools of molecular taxonomy. We present here the results of our molecular-assisted taxonomic studies on the Sargassum of the northern Philippines, particularly along the coasts of four coastal provinces in northwestern Luzon (i.e., Ilocos Norte, Ilocos Sur, La Union, and Pangasinan). We recognized three distinct species lineages, namely, Sargassum aquifolium (Turner) C.Agardh, Sargassum ilicifolium (Turner) C.Agardh, and Sargassum polycystum C.Agardh based on our molecular analyses of 74 specimens from our study areas. Our morphological observations on the range of characters of these species also suggest that several common Sargassum taxa in the Philippines have been misidentified. Particularly, specimens previously attributed to S. kushimotense Yendo should be referred as S. aquifolium while the widely distributed and highly plastic S. ilicifolium is often confused and identified in the Philippines under several names including S. crassifolium J.Agardh, S. cristaefolium C.Agardh, and S. turbinarioides Grunow. Taken together, our results suggest that Sargassum biodiversity in the Philippines may have been inflated by misidentifications, and, that species diversity is actually much lower than initially thought.