Nursheena Parveen Katermeran

Bio: Nursheena Parveen Katermeran is an academic researcher from National Institute of Education. The author has contributed to research in topics: Quorum sensing & Gammaproteobacteria. The author has an hindex of 1, co-authored 3 publications receiving 1 citations. Previous affiliations of Nursheena Parveen Katermeran include Nanyang Technological University.

Assessing the Diversity and Biomedical Potential of Microbes Associated With the Neptune's Cup Sponge, Cliona patera.

Abstract: Marine sponges are known to host a complex microbial consortium that is essential to the health and resilience of these benthic invertebrates. These sponge-associated microbes are also an important source of therapeutic agents. The Neptune’s Cup sponge, Cliona patera, once believed to be extinct, was rediscovered off the southern coast of Singapore in 2011. The chance discovery of this sponge presented an opportunity to characterize the prokaryotic community of C. patera. Sponge tissue samples were collected from the inner cup, outer cup and stem of C. patera for 16S rRNA amplicon sequencing. C. patera hosted 5,222 distinct OTUs, spanning 26 bacterial phyla, and 74 bacterial classes. The bacterial phylum Proteobacteria, particularly classes Gammaproteobacteria and Alphaproteobacteria, dominated the sponge microbiome. Interestingly, the prokaryotic community structure differed significantly between the cup and stem of C. patera, suggesting that within C. patera there are distinct microenvironments. Moreover, the cup of C. patera had lower diversity and evenness as compared to the stem. Quorum sensing inhibitory (QSI) activities of selected sponge-associated marine bacteria were evaluated and their organic extracts profiled using the MS-based molecular networking platform. Of the 110 distinct marine bacterial strains isolated from sponge samples using culture-dependent methods, about 30% showed quorum sensing inhibitory activity. Preliminary identification of selected QSI active bacterial strains revealed that they belong mostly to classes Alphaproteobacteria and Bacilli. Annotation of the MS/MS molecular networkings of these QSI active organic extracts revealed diverse classes of natural products, including aromatic polyketides, siderophores, pyrrolidine derivatives, indole alkaloids, diketopiperazines, and pyrone derivatives. Moreover, potential novel compounds were detected in several strains as revealed by unique molecular families present in the molecular networks. Further research is required to determine the temporal stability of the microbiome of the host sponge, as well as mining of associated bacteria for novel QS inhibitors.

Inhibition of Quorum Sensing System in Pseudomonas aeruginosa by Psammaplin A and Bisaprasin Isolated from the Marine Sponge Aplysinella rhax

Abstract: Natural products isolated from marine sponges have exhibited profound bioactivity and, in some cases, serve as potent quorum sensing inhibitory agents by preventing microbial biofilm formation. In this study, the inhibitory potential of the psammaplin type compounds, psammaplin A (1) and bisaprasin (2), isolated from the marine sponge, Aplysinella rhax, was evaluated in the quorum-sensing inhibitory assay based on the Pseudomonas aeruginosa PAO1 lasB-gfp and P. aeruginosa PAO1 rhlA-gfp biosensor strains. The result indicated that psammaplin A (1) showed moderate inhibition against lasB-gfp biosensor strains but significantly inhibited the QS-gene promoters, rhlA-gfp with IC50 value at 30.69 and 2.64 μM, respectively. In contrast, bisaprasin (2) displayed significant inhibition for both biosensor strains, lasB-gfp and rhlA-gfp with IC50 values at 8.70 and 8.53 μM, respectively. To our knowledge, the antiquorum sensing activity of these marine-derived bromotyrosine compounds is described here for the first time. Significance and Impact of the Study The attention of the scientific community has been drawn to using marine sources to find novel quorum sensing inhibitors as antipathogenic drugs to combat antimicrobial resistance and pathogenesis caused by the proliferation of pathogenic bacteria mediated by the quorum sensing (QS) system. By blocking the QS signalling communication, the ability to assemble an organised community structure that enables drug resistance and production of virulence factors will be attenuated. The significance of this investigation is based on the discovery of bromotyrosine derivatives as potential new drug leads for the development of antipathogenic agents.

Use of whole-cell bioreporters to assess bioavailability of contaminants in aquatic systems

Abstract: Water contamination has become increasingly a critical global environmental issue that threatens human and ecosystems’ health. Monitoring and risk assessment of toxic pollutants in water bodies is essential to identifying water pollution treatment needs. Compared with the traditional monitoring approaches, environmental biosensing via whole-cell bioreporters (WCBs) has exhibited excellent capabilities for detecting bioavailability of multiple pollutants by providing a fast, simple, versatile and economical way for environmental risk assessment. The performance of WCBs is determined by its elements of construction, such as host strain, regulatory and reporter genes, as well as experimental conditions. Previously, numerous studies have focused on the design and construction of WCB rather than improving the detection process and commercialization of this technology. For investigators working in the environmental field, WCB can be used to detect pollutants is more important than how they are constructed. This work provides a review of the development of WCBs and a brief introduction to genetic construction strategies and aims to summarize key studies on the application of WCB technology in detection of water contaminants, including organic pollutants and heavy metals. In addition, the current status of commercialization of WCBs is highlighted.

Marine natural products and their synthetic analogs as promising antibiofilm agents for antibiotics discovery and development.

Abstract: Biofilm is a complex microbial consortium that are embedded in a membrane structure of the extracellular polymeric substances (EPS). As a major form of microorganisms in nature, biofilm has evolved complex and diverse resistance mechanisms to numerous known antibiotics, posing a major threat to human health. The biofilm formation of pathogens including Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, etc. has become the most commonly reasons for clinically chronic and incurable infectious diseases, which urges the development of effective antibiofilm agents. The adaptation of marine organisms and microorganisms to their unique habitats has led to the formation of natural products with charming chemical diversity and biological activity, providing a rich reservoir for the development of antibiofilm agents. According to chemical classification, 129 marine-derived natural products and their synthetic analogs with antibiofilm activity were systematically reviewed, and the related mechanisms and efficacy were discussed as well, aiming to find and develop new and effective antibiofilm agents.

Triproamide and Pemukainalides, Cyclic Depsipeptides from the Marine Cyanobacterium Symploca hydnoides.

Abstract: A new cyclic depsipeptide, triproamide (1), containing the rare 4-phenylvaline (dolaphenvaline, Dpv) and a β-amino acid, dolamethylleucine (Dml), originally found in dolastatin 16, was isolated from the polar VLC-derived fraction of the extracts prepared from the marine cyanobacterium Symploca hydnoides. Triproamide (1) was isolated along with the known molecule kulokainalide-1 (2), as well as its two new analogues, pemukainalides A (3) and B (4). Their planar structures were elucidated based on extensive NMR and mass spectrometric data. The absolute and relative configurations of the compounds were determined utilizing a combination of Marfey's method, J-based configuration, and chiral-phase HPLC analyses. Kulokainalide-1 (2) and pemukainalide A (3) exhibited cytotoxicity against the MOLT-4 leukemia cell line with IC50 values of 5.9 and 5.6 μM, respectively.

Targeted Isolation of a Cytotoxic Cyclic Hexadepsipeptide from the Mesophotic Zone Sponge-Associated Fungus Cymostachys sp. NBUF082.

Abstract: LC-MS/MS-based molecular networking facilitated the targeted isolation of a new cyclic hexadepsipeptide, cymodepsipeptide (1), and two known analogues, RF–2691A (2) and RF–2691B (3), from the fungus Cymostachys sp. NBUF082 that was derived from a mesophotic zone Aaptos sponge collected near Apo Island. The constitution and configuration of 1 was elucidated through 1D and 2D NMR-spectroscopy, high resolution mass-spectrometry, and chemical degradations including Marfey’s analysis and chiral HPLC. It was observed that 1 was moderately cytotoxic against CCRF-CEM human acute lymphocytic leukemia cells in vitro with the IC50 value of 9.2 ± 1.1 μM.