TY  - JOUR
A1  - Balasubramanian, Srikkanth
A1  - Othman, Eman M.
A1  - Kampik, Daniel
A1  - Stopper, Helga
A1  - Hentschel, Ute
A1  - Ziebuhr, Wilma
A1  - Oelschlaeger, Tobias A.
A1  - Abdelmohsen, Usama R.
T1  - Marine sponge-derived Streptomyces sp SBT343 extract inhibits staphylococcal biofilm formation
JF  - Frontiers in Microbiology
N2  - Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to absence of cell toxicity, the extract might represent a good starting material to develop a future remedy to block staphylococcal biofilm formation on contact lenses and thereby to prevent intractable contact lens-mediated ocular infections.
KW  - medicine
KW  - marine sponges
KW  - actinomycetes
KW  - Streptomyces
KW  - staphilococci
KW  - biofilms
KW  - contact lens
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171844
VL  - 8
ER  - 
TY  - JOUR
A1  - Raheem, Dotsha J.
A1  - Tawfike, Ahmed F.
A1  - Abdelmohsen, Usama R.
A1  - Edrada-Ebel, RuAngelie
A1  - Fitzsimmons-Thoss, Vera
T1  - Application of metabolomics and molecular networking in investigating the chemical profile and antitrypanosomal activity of British bluebells (\(Hyacinthoides\) \(non-scripta\))
JF  - Scientific Reports
N2  - Bulb, leaf, scape and flower samples of British bluebells (Hyacinthoides non-scripta) were collected regularly for one growth period. Methanolic extracts of freeze-dried and ground samples showed antitrypanosomal activity, giving more than 50% inhibition, for 20 out of 41 samples. High-resolution mass spectrometry was used in the dereplication of the methanolic extracts of the different plant parts. The results revealed differences in the chemical profile with bulb samples being distinctly different from all aerial parts. High molecular weight metabolites were more abundant in the flowers, shoots and leaves compared to smaller molecular weight ones in the bulbs. The anti-trypanosomal activity of the extracts was linked to the accumulation of high molecular weight compounds, which were matched with saponin glycosides, while triterpenoids and steroids occurred in the inactive extracts. Dereplication studies were employed to identify the significant metabolites via chemotaxonomic filtration and considering their previously reported bioactivities. Molecular networking was implemented to look for similarities in fragmentation patterns between the isolated saponin glycoside at m/z 1445.64 [M + formic-H](-) equivalent to C64H104O33 and the putatively found active metabolite at m/z 1283.58 [M + formic-H](-) corresponding to scillanoside L-1. A combination of metabolomics and bioactivity-guided approaches resulted in the isolation of a norlanostane-type saponin glycoside with antitrypanosoma I activity of 98.9% inhibition at 20 mu M.
KW  - Drug discovery
KW  - Metabolomics
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224935
VL  - 9
ER  -