Sex: Male
Education:
- Doctor of Philosophy in Cell Biology, Kochi University, Japan, 2017
- Master of Science in University of the Philippines Diliman, 2014
- Bachelor of Science in Biology Pamantasan ng Lungsod ng Maynila, 2005
Field of Specialization:
Ecophysiology
Photosynthesis
Chlorophyll Fluorescence
Algae
Researches:
Article title: Marine macrophyte composition during summer, southwest and northeast monsoons in Verde Island, Batangas City, Batangas, Philippines
Authors: Jayvee Ablaña Saco, Najeen Arabelle M. Rula, John Matthew Arcega, Alvin Tabuga
Publication title: Philippine Journal of Systematic Biology, November 2020
Abstract:
Verde Island Passage is the world’s center of the center of marine shore fish biodiversity, located in southwestern Luzon Island in the Philippines. The passage is named after Verde Island, which is located at its middle. Although the island is located within a key biodiversity area, studies on its marine macrophyte biodiversity are scant. The present study was conducted to determine the composition, distribution, and dominance of marine macrophytes, specifically seaweeds and seagrass, during the northeast monsoon, summer, and southwest monsoon in four coastal areas in Verde Island using the line transect-quadrat method. Results revealed 63 macrophyte species, of which 92% were seaweeds and 8% were seagrass. The majority of the seaweeds were green (41%), followed by red (35%) and brown (16%) seaweeds. In most sites, the brown seaweed Padina sp. was dominant during summer and cover decreased during both monsoons. The green seaweed Neomeris annulata was present in all sites and seasons. The differences in cover across sites may be due to substratum type and topography where a relatively wider intertidal zone with different substratum such as rocky and sandy to muddy provides complex habitat promoting higher macrophyte cover. Temporal differences in marine macrophyte composition were more pronounced in macroalgae-dominated sites than in the seagrass-dominated site. Several important seaweeds that could be studied as bioindicators were recorded, such as Padina sp., which registered high cover especially in sites near populated areas and backyard pig pens. Ulva spp., which are known to form green tide blooms, and Caulerpa verticillata were also noted and should be monitored. Some red seaweeds with potential for cultivation were observed (i.e., Halymenia durvillei and Portieria hornemannii). Claudea sp., an uncommon red seaweed with limited distribution in the Philippines, was recorded and needs verification. This study is the first extensive marine macrophyte assessment at the heart of the Verde Island Passage.
Full text link https://tinyurl.com/uzf877x9
Article title: Photosynthetic fluctuation accompanied by translocation of chloroplasts in Ulva conglobata (Ulvophyceae) grown under a low irradiance regime
Authors: Jayvee Ablana Saco, Satoko Sekida, Ichiro Mine
Publication title: Phycological Research 69(2), November 2020
Abstract:
Fluctuations in photosynthetic characteristics related to chloroplast translocation have been known in the foliose green algae Ulva lactuca var. latissima and var. rigida and U. mutabilis according to photoperiod. In Ulva, the single parietal chloroplast is found along the thallus surface wall and exhibits high photosynthetic activity during the light period; the chloroplast then moves towards the side walls and shows low photosynthetic activity during the dark period. In this study, we re‐investigated whether the photosynthetic ability is dependent on chloroplast location in a unialgal culture of U. conglobata grown and maintained under low irradiance regime by analyzing in vivo absorption spectra, oxygen evolution, and pulse amplitude modulation chlorophyll fluorescence. The light absorbance of the thallus was higher when chloroplast was along the thallus surface wall than when along the side walls and, therefore, the thallus absorbance at 680 nm was used as an index of chloroplast position. Some photosynthetic parameters such as maximum net photosynthetic rate per thallus area and effective quantum yield of photosystem II correlated with the thallus absorbance. The highest rate and absorption were reached 3 to 9 h after the beginning of light period (12 h), which gradually decreased at 10 to 15 h after the beginning of light or dark period. The lowest rate and absorption was observed after the beginning of the dark period. The chloroplast movement was inhibited for 12 h by colchicine, and photosynthetic parameters were found to be dependent on various chloroplast positions in the thallus. Interestingly, the chloroplast moved to the surface and the side walls of the cells under continuous dark and light conditions, respectively, at approximately 48 to 72 h. However, decreased maximum quantum yield was observed under both continuous dark and light conditions.
Full text available upon request to the author
Article title: The VIP CORALS Marine Repository Hub: Laying foundations for science and discovery in the VIP
Authors: Najeen Arabelle M. Rula, Jayvee Ablaña Saco, Joshua M. Vacarizas, Jovy Ann Patchicoy Valera
Publication title: Philippine Science Letters 13(1), 2020
Abstract:
Full text link https://tinyurl.com/k2t3fkta
Article title: Characterization of photosynthesis and growth of Monostroma latissimum (Ulvophyceae) collected from the intertidal area in Kochi, Japan
Authors: Jayvee Ablaña Saco1,2, Satoko Sekida1, and Ichiro Mine
Publication title: Kuroshio Science 12-1, 2018
Abstract:
The photosynthesis and growth of the commercially important and edible green seaweed, Monostroma latissimum (Ulvophyceae), from a naturally occurring population in the intertidal area were examined in the laboratory. The natural population inhabits the middle to upper intertidal area and is usually attached to rocks. Cultivation occurs mostly in the shallow and calm waters under full light. The species was subjected to 10, 15, 20, or 25°C temperatures, and irradiances ranging from 0 to 1200 μmol photon m-2 s-1 in order to evaluate the effect of photosynthesis on growth. Photosynthesis was determined and characterized using photosynthesis-irradiance curves from oxygen production and PAM fluorometry. The maximum net photosynthetic rate (per thallus area and total chlorophyll content) did not differ significantly at the different temperatures, which were chosen to reflect the autumn to mid-spring temperatures that the seaweed would be expected to experience. The growth rates over 5 and 10 days were the same for all temperatures, but it decreased at 25°C after 15 days of culturing, which suggested that prolonged exposure to higher temperatures might have an adverse effect on growth. Similarly, the maximum quantum yield decreased as the temperature increased, which indicated that photosystem II (PSII) was under physiological stress at higher temperatures. In contrast, the light compensation point, saturating irradiance, initial slope, and PSII light absorption efficiency increased as the temperature rose. This suggested that the species optimized photosynthesis to accommodate the low and high light conditions that it may experience through its growing season. These conditions are characterized by irradiance limitation and low temperatures in winter, and higher irradiance and temperatures in spring. There were no photoinhibitory responses, which suggested that this alga was tolerant to higher irradiance. The growth rate significantly increased as irradiance rose, which may indicate higher growth rate responses at higher irradiances. Overall, the photosynthetic responses were in parallel with the growth rate response by M. latissimum. Therefore, the results from this study on M. latissimum, photosynthetic characteristics can be used to improve its cultivation.
Full text link https://tinyurl.com/5dfa7xyr
Article title: Chloroplast position and photosynthetic characteristics in two monostromatic species, Monostroma angicava and Protomonostroma undulatum (Ulvophyceae), having a shared ecological niche: Chloroplast position and photosynthesis
Authors: Jayvee Ablaña Saco, Akio Murakami, Satoko Sekida and Ichiro Mine
Publication title: Phycological Research 66(1):58-67, September 2017
Abstract:
Monostroma angicava and Protomonostroma undulatum are monostromatic green benthic algae (Ulvophyceae), which grow together in the same intertidal habitat of Muroran, Hokkaido, Japan, during the spring season. Commonly, both species have a single chloroplast with one pyrenoid per cell. The parietal chloroplast is located on the periphery of the thallus in both species, although the location of the chloroplast differs in the two. In M. angicava, the chloroplast was observed to be arranged on one-side of the thallus surface, whereas, in P. undulatum, it was dispersed and randomly located on either side of the thallus or on the lateral face. The density of chlorophylls (Chls) assessed from the absorption spectra of the thallus and its solvent extract was higher in M. angicava, which appeared dark-green in color, than in the light-green colored P. undulatum. The maximum photosynthetic rate per thallus area (μmol O2 m⁻² s⁻¹) was higher in M. angicava, whereas, per total chlorophyll content (μmol O2 g Chl a + Chl b⁻¹ s⁻¹) was higher in P. undulatum. Both species showed similar efficiency of photosynthesis at light-limiting conditions. The efficiency of light absorption by photosystem II (PSII) in P. undulatum was higher than M. angicava, whereas the photoprotective response was higher in M. angicava. This indicates that more energy is utilized in M. angicava to protect its PSII due to the chloroplast position, which has more direct exposure to light and, therefore, lowers the efficiency of light absorption by PSII. The higher density of chlorophylls in M. angicava could explain higher photosynthesis per thallus area, whereas, higher efficiency of light absorption by PSII in P. undulatum could explain higher photosynthesis per total chlorophyll content. The differences in light absorption efficiency and quantum efficiency of PSII might be an important ecological strategy in these two species for their coexistence in the intertidal area.
Full text available upon request to the author