Late maturation and large size at maturity are significant challenges when administering hormonal treatments in captive broodstock. Here, we report the potential of yeast, Pichia pastoris, as a vehicle to orally deliver a recombinant gonadotropin-releasing hormone (rGnRH1) aimed at stimulating gonadal development in juvenile orange-spotted grouper, Epinephelus coioides. Two recombinant GnRH1 constructs were designed utilizing pPIC3.5, the yeast expression vector lacking a signal sequence, hence retaining the recombinant within the yeast. The first construct (rGnRH1_1xGAP) comprised of GnRH1 decapeptide and the GnRH-associated peptide (GAP) separated by a cleavage site. The second construct (rGnRH1_10x) consisted of ten GnRH1 decapeptides, each separated by a cleavage site. Expression of the two recombinant peptides was confirmed by mass spectrometry. ELISA for the GnRH analogue (GnRHa) was validated to determine the level of rGnRH1 from the yeast extracts. Parallelism between the serially diluted GnRHa and serially diluted extracts from recombinant yeast confirmed validity of the assay. A luciferase reporter assay showed stimulation of tilapia GnRH type 3 receptor by the yeast extract, suggesting biological activity in vitro. In a short term experiment, lyophilised yeast loaded in gelatine capsules and fed once to juvenile orange-spotted grouper resulted in a significantly higher plasma GnRH compared with the control. In a 4-week experiment, lyophilized yeast containing either rGnRH1_1xGAP or rGnRH1_10x was incorporated in fish pellets and fed daily at a dose of 1 μg rGnRH1/kg fish body weight/day. The mean gonadosomatic index and oocyte diameter did not vary between the treated and control fish. The mean plasma levels of FSH, LH and GnRH in the rGnRH1-fed and control fish did not also vary significantly, however there were individuals in the rGnRH1-fed groups that had increased level of the hormones. Together with histological evidence showing oocyte development in a proportion of fish fed with the recombinant, results of the present study point to a biological activity in vivo of the rGnRH1 in yeast. With further refinement, this technology has the potential to provide a non-invasive method for broodstock management of large, late-maturing species of fish and of small, delicate endangered species that require breeding in captivity.

The Agusan Marsh is the 1009th RAMSAR site, a wildlife sanctuary which serves as wintering ground for migratory and wetland birds from Asian and Western countries, and is considered one of the most ecologically significant wetland ecosystems in the Philippines. This study assessed species diversity and distribution of birds in four habitat types of the Agusan Marsh. Sago, Terminalia, Mixed Swamp and Peat Swamp forests in the Marsh were surveyed from August 2005 to January 2006 using a combination of mist netting (3,337 net days) and transect walk methods. One hundred twenty-six species of birds were identified consisting of 26 migrants, 69 non-endemics, and 31 endemics (23.81% endemism) of which seven species are categorized as threatened. The Mixed Swamp Forest had the highest species richness (S=92) while the Peat Swamp Forest had the highest number of migratory birds (S=26). Highest endemicity was recorded in the Terminalia Forest (20.63%) while the Sago Forest had the least number of bird species. Migratory birds were recorded at the start of sampling in August, their numbers considerably increasing thereafter and reaching a peak in November. In contrast, the number of endemic species declined in the same month. Previously recorded only in Luzon, the migratory Siberian Rubythroat (Luscinea calliope) was also found in Agusan Marsh, indicating that this bird may be found in other places in the Philippines. Forty-six species of birds, which include six migratory species, were reported to be of socioeconomic importance. Changes in structural and floristic composition brought about by forest degradation, such as conversion of forest into agriculture, logging and hunting, were seen as threats to the birds in Agusan Marsh. Results indicate that the Marsh supports a considerable number of endemic, threatened, and migratory bird species. Conservation of the different Marsh habitats is necessary for the protection of the broadest avifaunal diversity.

The Butuan coastal plain is a fan-delta formed by deposition of Agusan River sediments in the past 7,400 radiocarbon years (ky). Traces of paleochannels that scar the coastal plain, seen in satellite images, indicate past river positions. Immediately prior to the present, Masao River was the active distributary as suggested by its well-defined and still continuous paleochannel. Numerous sudden shifts of river position have likely originated in the San Vicente area, the apex region of the fan-delta. These shifts could have been self driven or induced by floods or tectonics. Sediment input from rivers along the eastern flank of the Butuan coastal plain forced a number of downstream shifts. The function of the Agusan Marsh in buffering flashy river discharges in the Butuan coastal plain is threatened by present-day elevated sediment loads of rivers upstream.

This is the first report on hydrodynamic models to determine current and water residence time patterns for Matarinao and Murcielagos bays in the Philippines, which have a long history of harmful algal blooms (HABs). Field surveys were conducted in Matarinao Bay in April and August 2010 and in Murcielagos Bay in February 2011. Hydrodynamic models of the bays were developed, and spatially explicit water residence times were estimated from the models based on rates of concentration decrease of a tracer within the bay. Both bays exhibited two distinct areas – the mouth with faster current flow and low residence time, and the head area with slower current flow and higher residence time. During the southwest monsoon, the residence time at Matarinao Bay was 5 d longer than that during the northeast monsoon. Phytoplankton sampling in both bays confirmed blooms of Pyrodinium bahamense, but the spatial distribution did not consistently correlate with the simulated residence time patterns. While residence time plays a significant role in algal blooms, extraneous factors may also influence the distribution of phytoplankton within embayments.

The phytochemical constituents, total phenolic and flavonoid contents, antioxidant and antimicrobial activities of the ethanolic extract of the marine green alga Ulva pertusa collected from floating fish net cages off the coast of Guimaras island, Philippines, were investigated. Qualitative phytochemical analysis revealed the presence of bioactive compounds including alkaloids, flavonoids, phenols, saponins, tannins, and terpenoids. Quantitatively, total phenolic and flavonoid contents of the extract were 20.54±2.08 mg gallic acid equivalent (GAE) g^-1 and 539.07±6.36 mg rutin equivalent (RE) g^-1, respectively. The antioxidant activity of the extract using 1,1-diphenyl-1-picrylhydrazyl (DPPH) assay exhibited a concentration-dependent radical scavenging capacity. Additionally, the ethanolic extract inhibited the growth of Staphylococcus aureus ATCC25923, Escherichia coli ATCC25922, Streptococcus agalactiae, Aeromonas hydrophila, A. sobria, and Vibrio harveyi in a concentration-dependent manner with strong inhibitory activity at 100 mg mL^-1 concentration. Taken together, U. pertusa contains bioactive compounds that possess potent antibacterial activity and remarkable antioxidant capacities. These substances are promising candidates that may be utilized in the synthesis of novel drugs.