Author: ovcre.upvisayas

Tropical mangrove ecosystems are known for high productivity and extensive ecosystem services. While there has been extensive research on floristics and faunistics in mangroves, there has been limited information in community structure and carbohydrate analysis of flower nectars, which can be explored for possible apiculture. The study was conducted to assess community structure, species diversity, and total carbohydrate (TC) analysis of floral nectars in 15 mangrove sites in Maqueda Bay, Matarinao Bay, and Leyte Gulf in Samar, Eastern Samar, and Leyte, respectively. A total of 15 sites were assessed using the transect line-plot method. A total of 23 mangrove species were identified from the 15 sites (2 dominant, 17 minor, and 2 associated species) belonging to 12 families, including 21 true mangroves and 2 mangrove associates. Leyte Gulf and Maqueda Bay have 17 species, while Matarinao Bay has 13 species. In general, the mangrove sites are dominated by Rhizophora apiculata and Sonneratia alba. Rehabilitated sites are dominantly planted with Rhizophora. In contrast, natural mangrove stands are composed of mixed species of Aegiceras, Avicennia, Brugueira, Rhizophora, Sonneratia, and Xylocarpus. Across the three habitats, S. alba showed much higher nectar TC (mg) per flower than R. apiculate ranging from 7.45 – 0.02 mg/ flower. These data suggest that sites dominated with S. alba has good prospects for apiculture, considering the total carbohydrate analysis, over the popularly planted R. apiculata.

An essential element for describing and predicting the dynamic behavior of interacting components within a biochemical system is the formulation of mathematical models. One of the widely used mathematical models is the power-law formalism-based S-systems. However, parameter estimation in S-systems continues to be a difficult challenge because of the nonlinearity and high dimensionality of the underlying coupled systems of ordinary differential equations. Hence it is important to provide efficient and effective novel methods to tackle parameter estimation problem. In this paper, we use decoupling technique on the S-system and then Xin- She Yang’s Firefly Algorithm (FA), a metaheuristic algorithm based on the bioluminescence process which characterizes fireflies, as optimization algorithm in the parameter estimation. FA’s automatic subdivision of the whole population into subgroups and natural capability of dealing with multi-modal optimization are the two major advantages of FA over other algorithms, making FA a good algorithm choice. Using three S-systems of increasing complexity from the MADMan Benchmarking Framework, we assess the performance of the method. Simulation results show that FA-decoupling method is applicable in estimating parameters of the 3 S-system models using noise-free data with concentration error lower than 10-3 and better approximations were recorded for kinetic orders than rate constants. Since FA-decoupling method worked on parameter estimation of S-system models using noise-free data, it is now reasonable to implement the method using datasets with different noise levels to check how the method is affected by the presence of noise.

Image segmentation is the process of partitioning an image into a set of distinct regions. Some of its practical applications are in medical image processing, facial and fingerprint recognition, object detection, and more. During image acquisition or transmission, the images may be corrupted by noise which affects the accuracy of segmentation applications. In this paper, we present a modified version of the Chan-Vese model for segmenting images with Gaussian noise. The modification is mainly a change on the total variation (TV) term of the discretized Chan-Vese model where we considered the use of a nonconvex TV q – type norm where q∈(0,1) . To solve both global and local regularized versions of the proposed model, we used a steepest descent method. Numerical results are provided in this paper to show the efficiency of the proposed model in segmenting noisy images.

This study aims to evaluate the antimelanogenic activity of terrestial plants Cassia alata, Capsicum frutescens, Tabernaemontana pandacaqui, Colocasia esculenta and Alocasia macrorhizos which are known to have medicinal value. The antimelanogenic activity was determined using the zebrafish model. Embryos at 9 hr post fertilization (hpf) were treated with the crude extracts of each plant at 50 μg/mL and 100 μg/mL concentrations and were exposed up to 55 hpf. Ocular melanin content was estimated using Image J. C. alata leaf extracts showed the most promising antimelanogenic activity among the plant samples tested. Dosedependent assay showed that at 500 μg/mL, 70% of the embryos had profound decrease in melanin. At the same concentration, the ocular melanin content of the zebrafish decreased 2-fold. Results suggest that the leaf of C. alata is a potential source of compounds with inhibitory activity against melanin production.

The East Sulu Sea, the area off the coast of the Zamboanga peninsula, is one of the major fishing grounds for sardine in the Philippines principally driven by primary production that follows seasonal upwelling in the area. Chaetognaths are zooplankton predators whose abundances may serve as control to overall plankton biomass in such productive waters. This study aims to compare and characterize chaetognath assemblages associated with structural attributes between high and low production areas within an upwelling area. Zooplankton were collected in February 2013 during an upwelling season using a 45cm-diameter NORPAC net with a 200um mesh bag attached to it. Three depth intervals (0-65m, 65-135m and 135-200m) were examined in each station for the vertical profiling of zooplankton. The mean zooplankton biomass for the high (Stn 24) and low (Stn 22) production stations were 51.8 ml 100m-3 and 75.8 ml 100m-3, respectively. A total of 993 chaetognaths with an average density of 47.5 ind. m-3 were collected from the Stn 24, and only 334 individuals accounting for an average density of 10.6 ind. m-3 from the Stn 22. The results show an aggregation of chaetognaths in the surface layer of the two stations, particularly in the high production station, contributing 80.96 ind. m-3 to the total zooplankton. Flacisagitta enflata was the most dominant species found in both stations. This study suggests that physical and biological controls may dictate chaetognath assemblage composition and distribution.

This study describes the development of an enriched culture media for growth, biomass and carotenoid production of the photosynthetic bacteria Rhodobacter sphaeroides PSB1 through supplementation of fish processing wastes in the Acetate Yeast Extract (AYE) medium. Proximate compositions of the fish processing wastes were determined prior to supplementation. Cultures were incubated and analyzed for growth, biomass and carotenoid production after 14 days. Results showed that addition of fish viscera yielded significantly higher (P<0.05) growth (2.75 x105 ml-1 cells), protein content (71.37 μg mL-1) and carotenoid production (22.11 mg L-1) than supplementation of fish frames and control which may be attributed to the high protein and lipid content of the viscera. Biomass production was however higher in cultures supplemented with fish frames (22.67 g L1) which showed higher ash content than the viscera. Findings of this study showed that fish processing wastes may be used as supplemental nutrient source to promote the growth, biomass, protein and carotenoid production of R. sphaeroides, an industrially-important photosynthetic bacterium.

Garcinia rubra Merr. (‘kamandiis’) belongs to the Clusiaceae (Guttiferae) family and is one of the indigenous Garcinia species in the Philippines that has not been extensively studied yet. In this study, the phytochemical constituents in the crude leaf extracts of kamandiis was determined. Results showed that kamandiis contains carbohydrates, glycosides, tannins, phenolics, flavonoids, terpenoids and steroids. Carbohydrates and glycosides were found in ethanolic extract while tannins, phenolics and flavonoids were found in both ethanolic and ethyl acetate extracts. On the other hand, terpenoids and steroids were observed in dichloromethane (DCM) and hexane extracts. Results therefore suggest that kamandiis could be a source of these phytochemicals and may be further studied for its promising application in the pharmaceutical industry and alternative medicine.

The seagrass ecosystems along the intertidal areas of Tacloban City, Philippines were rapidly assessed in October 7-29, 2017. This was specifically aimed to map the areas covered by seagrass beds, determine species composition, distribution, and abundance, and identify potential threats to these ecosystems. Seagrass beds observed in Cancabato Bay, Anibong Bay, Brgys. Tigbao-Diit, Brgy. Bagacay, Brgy, Cabalawan, Brgy. Suhi (San Isidro), Brgys. Sto. Niño-Kawayan and Tagpuro cover an area of at least 54,503 m2 or 54.2 ha. Only 4 seagrass species were identified from all the sites, namely: Enhalus acoroides (Linnaeus f.) Royle, Thalassia hemprichii (Ehrenberg) Ascherson, Cymodocea serrulata (R. Brown) Ascherson & Magnus, and Halodule uninervis (Forsskål) Ascherson. E. acoroides was the most widely distributed of all the species. The average seagrass cover and biomass were 42.0 ± 9.5 %/m2 and 53.8 ± 6.6 g dry weight/m2, respectively. Some potential threats to adjacent seagrass beds such as, direct discharge of untreated wastewater, presence of fish pens, plastic pollution, human dwellings, docking areas for pumpboats, recreational areas, man-made intertidal structures, sedimentation, oil pollution and destructive shellfish gleaning were observed and subsequently, geotagged.

Pyrodinium bahamense has been one of the most frequently blooming dinoflagellate species in the years 2016–2018 in Cirebon waters, Indonesia, and is also related to several cases of paralytic shellfish poisoning (PSP). This study aimed to examine the distribution of the cysts of P. bahamense in the sediments of Cirebon waters. The cyst density of P. bahamense in the study area ranged from 27 to 493 cysts/g of wet sediment. The highest abundance of P. bahamense cysts was recorded in sampling sites with high anthropogenic activities, coinciding with the sites having a higher percentage of silt and clay in the sediment and where periodic dinoflagellates blooms occur. These results indicate the need for further studies to understand the dynamics of P. bahamense population in Cirebon and mitigate its future bloom. Measurement of factors such as pollution, eutrophication, water circulation, and sediment transport will have to be done.