Abstract:
Subic Bay is a coastal marine ecosystem with a variety of habitats and marine
organisms. Despite its ecological importance, the microbial communities in this bay
have not been thoroughly studied, and human activities may have impacted these
microbial communities, disrupting the delicate ecosystem balance. A diverse port water
community has the potential to produce biologically active compounds such as
antimicrobial peptides (AMPs). The study analyzed the 3rd sampling run of year 2
paired-end metagenomic sequences provided by the PORTEC project; with
bioinformatic pipelines such as assembly, genome annotations and peptide mapping.
Taxonomic profiling identified Proteobacteria and Firmicutes as the most abundant
phyla. Actinomycetes' low abundance could be explained by factors such as intense
competition from other microorganisms, a scarcity of suitable substrates, fluctuating
water levels and oxygen availability, and high salinity and alkaline pH in the port water.
AMP prediction resulted in 86 putative peptides, suggesting adaptability and resistance
to microbial infections within the community. When these sequences were compared to
existing databases, only four of them showed similarities to known entries. Among the
matches, an amino acid sequence ("VVVVVVVVVVVVVVVVVVVVVVVVVVVC") was
found in multiple uncharacterized proteins. Peptides high in valine are uncommon which
suggest that they have no specific advantages; however, studies show that they
improve protein stability or functionality, implying the presence of metabolic pathways
that confer a survival advantage.
