Identification of Sponge-Associated Bacteria From the Coast of Kuwait and Their Potential Biotechnological Applications

Sponges are among the most ancient animals harboring complex microbial communities with potential applications in biotechnology. The Arabian Gulf is a thermally stressed enclosed body of water located in an arid region where sponges and their halobionts are understudied. This study combined 16S rRNA next-generation gene amplicon sequencing and cultivation techniques to explore the abundance and diversity of sponge-associated bacteria. Culture-independent techniques showed the associations of more than 25 bacterial phyla with Amphimedon sp., Chondrilla australiensis, Haliclona sp., and Niphates spp. Regarding cultivable bacteria, 315 bacterial isolates associated with the sponge Haliclona sp. were cultivated; these isolates were affiliated with the phyla Proteobacteria and Firmicutes and were distributed among six bacterial genera. Selected strains of Bacillus, Ferrimonas, Pseudovibrio, Shewanella, Spongiobacter, and Vibrio were tested for antimicrobial activity against indicator microorganisms and protease enzyme production. Seven Bacillus strains exhibited weak to moderate growth inhibition against Bacillus subtilis, Staphylococcus aureus, and Candida albicans. Furthermore, 29 different strains of Bacillus, Ferrimonas, Shewanella, and Vibrio exhibited different degrees of positive protease activity. In addition, cultivated strains of Bacillus, Shewanella, Pseudovibrio, and Vibrio were tested for their biomineralization abilities. Herein we report for the first time the isolation of biomineralizing bacteria from sponge tissue where eleven bacterial isolates produced different shapes of calcium carbonate crystals on agar. Our observations shed light on the diversity and biotechnological potentials of sponges-associated bacteria inhabiting one of the world’s hottest seas.

Integrating Molecular Networking and 1H NMR Spectroscopy for Isolation of Bioactive Metabolites from the Persian Gulf Sponge Axinella sinoxea

The geographic position, highly fluctuating sea temperatures and hypersalinity make Persian Gulf an extreme environment. Although this unique environment has high biodiversity dominated by invertebrates, its potential in marine biodiscovery has largely remained untapped. Herein, we aimed at a detailed analysis of the metabolome and bioactivity profiles of the marine sponge Axinella sinoxea collected from the northeast coast of the Persian Gulf in Iran. The crude extract and its Kupchan subextracts were tested in multiple in-house bioassays, and the crude extract and its CHCl₃-soluble portion showed in vitro antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium (Efm). A molecular networking (MN)-based dereplication strategy by UPLC-MS/MS revealed the presence of phospholipids and steroids, while ¹H NMR spectroscopy indicated the presence of additional metabolites, such as diketopiperazines (DKPs). Integrated MN and ¹H NMR analyses on both the crude and CHCl₃ extracts combined with an antibacterial activity-guided isolation approach afforded eight metabolites: a new diketopiperazine, (-)-cyclo(L-trans-Hyp-L-Ile) (8); a known diketopiperazine, cyclo(L-trans-Hyp-L-Phe) (7); two known phospholipids, 1-O-hexadecyl-sn-glycero-3-phosphocholine (1) and 1-O-octadecanoyl-sn-glycero-3-phosphocholine (2); two known steroids, 3β-hydroxycholest-5-ene-7,24-dione (3) and (22E)-3β-hydroxycholesta-5,22-diene-7,24-dione (4); two known monoterpenes, loliolide (5) and 5-epi-loliolide (6). The chemical structures of the isolates were elucidated by a combination of NMR spectroscopy, HRMS and [α]_D analyses. All compounds were tested against MRSA and Efm, and compound 3 showed moderate antibacterial activity against MRSA (IC₅₀ value 70 μg/mL). This is the first study that has dealt with chemical and bioactivity profiling of A.sinoxea leading to isolation and characterization of pure sponge metabolites.

Toxicity of nanotitanium dioxide (TiO2-NP) on human monocytes and their mitochondria

The effect of nanotitanium dioxide (TiO₂-NP) in human monocytes is still unknown. Therefore, an understanding of probable cytotoxicity of TiO₂-NP on human monocytes and underlining the mechanisms involved is of significant interest. The aim of this study was to assess the cytotoxicity of TiO₂-NP on human monocytes. Using biochemical and flow cytometry assessments, we demonstrated that addition of TiO₂-NP at 10 μg/ml concentration to monocytes induced cytotoxicity following 12 h. The TiO₂-NP-induced cytotoxicity on monocytes was associated with intracellular reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) collapse, lysosomal membrane injury, lipid peroxidation, and depletion of glutathione. According to our results, TiO₂-NP triggers oxidative stress and organelles damages in monocytes which are important cells in defense against foreign agents. Finally, our findings suggest that use of antioxidants and mitochondrial/lysosomal protective agents could be of benefit for the people in the exposure with TiO₂-NP.

Single-walled carbon nanotube, multi-walled carbon nanotube and Fe2O3 nanoparticles induced mitochondria mediated apoptosis in melanoma cells

PURPOSE

Nanomaterials (NM) exhibit novel anticancer properties.

MATERIALS AND METHODS

The toxicity of three nanoparticles that are currently being produced in high tonnage including single-walled carbon nanotube (SWCNT), multi-walled carbon nanotube (MWCNT) and Fe₂O₃ nanoparticles, were compared with normal and melanoma cells.

RESULTS

All tested nanoparticles induced selective toxicity and caspase 3 activation through mitochondria pathway in melanoma cells and mitochondria cause the generating of reactive oxygen species (ROS), mitochondrial membrane potential decline (MMP collapse), mitochondria swelling, and cytochrome c release. The pretreatment of butylated hydroxytoluene (BHT), a cell-permeable antioxidant and cyclosporine A (Cs. A), a mitochondrial permeability transition (MPT), pore sealing agent decreased cytotoxicity, caspase 3 activation, ROS generation, and mitochondrial damages induced by SWCNT, MWCNT, and IONPs.

CONCLUSIONS

Our promising results provide a potential approach for the future therapeutic use of SWCNT, MWCNT, and IONPs in melanoma through mitochondrial targeting.

Xylene Induces Oxidative Stress and Mitochondria Damage in Isolated Human Lymphocytes

Xylene is a cyclic hydrocarbon and an environmental pollutant. It is also used in medical technology, paints, dyes, polishes and in many industries as a solvent; therefore, an understanding of the interaction between xylene and human lymphocytes is of significant interest. Biochemical assessment was used to demonstrate that exposure of lymphocytes to xylene induces cytotoxicity (at 6 hr), generates intracellular reactive oxygen species, collapse of mitochondrial membrane potential, lysosomal injury, lipid peroxidation and depletion of glutathione (at 3 hr). The findings show that xylene triggers oxidative stress and organelle damage in lymphocytes. The results of our study suggest that the use of antioxidant, mitochondrial and lysosomal protective agents can be helpful for individuals subject to chronic exposure to xylene.

Methotrexate induced mitochondrial injury and cytochrome c release in rat liver hepatocytes

Methotrexate (MTX) is a folic acid antagonist that is widely used to treat a variety of diseases. One of the most serious side effects of MTX therapy is hepatotoxicity. The potential molecular cytotoxic mechanisms of MTX toward isolated rat hepatocytes were investigated using Accelerated Cytotoxicity Mechanism Screening (ACMS) techniques. A concentration and time dependent increase in cytotoxicity and reactive oxygen species (ROS) formation and a decrease in mitochondrial membrane potential (MMP) were observed with MTX. Furthermore, a significant increase in MTX (300 μM)-induced cytotoxicity and ROS formation were observed when glutathione (GSH)-depleted hepatocytes were used whereas addition of N-acetylcysteine (a GSH precursor) decreased cytotoxicity. Catalase inactivation also increased MTX-induced cytotoxicity, while the direct addition of catalase to the hepatocytes decreased cytotoxicity. MTX treatment in isolated rat mitochondria caused swelling and significantly decreased adenosine triphosphate (ATP) and GSH content, and cytochrome c release. Potent antioxidants such as mesna, resveratrol and Trolox decreased MTX-induced cytotoxicity and ROS formation and increased MMP. This study suggests that MTX-induced cytotoxicity caused by ROS formation and GSH oxidation leads to oxidative stress and mitochondrial injury in rat hepatocytes.