1.Shotgun metagenomic analysis of microbial communities in the surface waters of the Eastern South China Sea
Jessica Song ; Aazani Mujahid ; Po-Teen Lim ; Azizan Abu Samah ; Birgit Quack ; Klaus Pfeilsticker ; Sen-Lin Tang ; Elena Ivanova ; Moritz Müller
Malaysian Journal of Microbiology 2017;13(4):350-362
Aims: The South China Sea (SCS) harbours a rich biodiversity. However, few studies have been published on its
diverse communities, particularly its microbial counterparts. As key players behind many of the vital processes carried
out in the ocean, microbes are the focus of this study, placing particular emphasis on community composition, structure,
and function.
Methodology and results: By employing next generation shotgun sequencing technologies (Illumina HiSeq2000), we
assessed the taxonomic structure and functional diversity of the prokaryotic communities in surface waters collected
from 3 representative sites in the Eastern SCS: Sarawak (Kuching), Sabah (Kota Kinabalu), and Philippines (Manila).
Comparisons were undertaken to similar studies from coastal and open ocean environments. All 3 locations were
dominated by members of the Proteobacteria (Alpha- and Gamma-) and Cyanobacteria (Synechococcus sp. and
Prochlorococcus sp.). The highest proportion of Gammaproteobacteria was found in Sarawak, representing an
approximate 20% of total sequences. Archaeal assemblages were made up largely of Euryarchaeota and unclassified
sequences, while Crenarchaeota and Thaumarchaeota were present in much smaller proportions, except in the
Philippines where Thaumarchaeota made up almost 40% of the entire taxa.
Conclusion, significance and impact of study: The majority of the microbial communities adhered to a core set of
functional genes across the different locations. However, differences existed particularly in Sarawak waters which are
hypothesized to be due to local environmental parameters such as riverine influence. The results obtained from this
study provide the first comparison of prokaryotic communities in the surface waters of the eastern SCS and will serve as
a good platform for prospective studies in the field of environmental science.
2.Biosorption and proteomic analysis of an encapsulated endophytic heavy-metal resistant Pestalotiopsis sp.
Jenny Choo ; Norasfaliza Rahmad ; Jameel R. Al-Obaidi ; Aazani Mujahid ; LikFong Ting ; Moritz Mü ; ller
Malaysian Journal of Microbiology 2019;15(7):505-517
Aims:
A study on biosorption ability using encapsulated endophytic fungi has been carried out to investigate its biosorption potential in removing heavy metals. Biosorption has emerged as an alternative bioremediation process to remove and sequester heavy metal ions from polluted water. An endophytic Pestalotiopsis sp. (isolated from Nypa fruticans) was found to be able to resist copper (Cu), chromium (Cr), lead (Pb) and zinc (Zn) up to 1,000 ppm and thus the aim of this study was to investigate the biosorption ability using encapsulated live and dead Pestalotiopsis sp. biomass (at pH 4-6) to remove heavy metals. Additionally, a proteomic study was conducted to investigate down- and up-regulation expression levels of proteins under the treatment of the heavy metals.
Methodology and results:
Encapsulated live fungal biomass displayed higher efficiency in removing chromium at pH 5 and 6, while both encapsulated live and dead biomass were able to remove lead at pH 4 and 5 and copper at pH 5. Five (5) proteins of interest were identified via MALDI-ToF analysis. Among the proteins identified, multidrug resistance protein (MRP homolog) was up-regulated in the presence of lead.
Conclusion, significance and impact of study
The data obtained in this study provides an initial understanding of the biosorptive and defensive mechanisms of Pestalotiopsis sp. under heavy metal stress.