Molecular docking and antibacterial activity of Sargassum fusiforme extracts against major coral pathogens.

The present study evaluates the antibacterial properties of alkaloids and the crude extracts (ethanol, n-hexane and ethyl acetate) from seaweed Sargassum fusiforme against coral pathogens (Photobacterium galatheae, Vibrio harveyi, Bordetella trematum, and Ochrobactrum pseudogrignonese) isolated from coral Porites lutea. To our knowledge, this is the first in vitro assay for such extracts on Porites lutea coral pathogens. Bacterial pathogens have been identified using 16S RNA and BankIt into gene bank and given the accession numbers (OR401000; OR401001; OR401336, and OR400998 respectively). GC-Mass profiling conducted for n-hexane compounds confirmed the presence of thirty-eight molecules, twelve of which have been previously reported for their bioactivity. The results revealed that alkaloids and n-hexane extract demonstrated eminent antibacterial activity compared to the other extracts against the tested coral pathogenic bacteria. Molecular docking was conducted to evaluate the twelve previously mentioned bioactive molecules to get a full understanding of the interaction of those bioactive molecules on vital bacterial proteins (Hemolysin protein (PDB ID: 1XEZ) and Cytoplasmic proteins (PDB ID: 3TZC)). Docked twelve molecules against hemolysin protein (PDB ID: 1XEZ) came exactly in line with the docked result of the same molecules with cytoplasmic proteins (PDB ID: 3TZC), proving the bioactivity of 6-O-Palmitoyl-L-ascorbic acid, 3TMS derivative; Glycerol monostearate, 2TMS derivative and Eicosanoic acid complexes in antibacterial activity action and score higher than reference ligand. Those three compounds will be investigated separately in future in vitro assay soon. Our conclusions align with the study's antibacterial in vitro assay results. The present study reports the novelty of different extracts of S. fusiforme as an antibacterial agent against coral pathogenic bacteria that trigger diseases in Porites lutea.

Microbial community shift on artificial biological reef structures (ABRs) deployed in the South China Sea.

Many Artificial Reefs (ARs) have been used worldwide for marine habitat and coral reef restoration. However, the microbial community structure that colonize the ARs and their progressive development have been seldom investigated. In this study, the successive development of the microbial communities on environmentally friendly Artificial Biological Reef structures (ABRs)R made of special concrete supported with bioactive materials collected from marine algal sources were studied. Three seasons (spring, summer and autumn), three coral reef localities and control models (SCE) without bioactive material and (NCE) made of normal cement were compared. The structure of the microbial pattern exhibited successive shifts from the natural environment to the ABRs supported with bioactive materials (ABAM). Cyanobacteria, Proteobacteria, and Planctomycetota were shown to be the most three dominant phyla. Their relative abundances pointedly increased on ABAM and SCE models compared to the environment. Amplicon Sequence Variant (ASV) Richness and Shannon index were obviously higher on ABAM models and showed significant positive relationship with that of macrobenthos than those on the controls and the natural reef (XR). Our results offer successful establishment of healthy microbial films on the ABR surfaces enhanced the restoration of macrobenthic community in the damaged coral reefs which better understands the ecological role of the ABRs.

Enhanced antimicrobial activity of lactic acid bacteria through genome shuffling and genetic variability among shuffled strains.

In this investigation, lactic acid bacteria (LAB) isolated from milk were tested for their antibacterial properties and improved the antimicrobial activity of these isolates using genome shuffling. A total of sixty-one isolates were found in eleven samples, which were then tested using the agar diffusion method for their antibacterial activity against Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa. Thirty-one strains exhibited antibacterial activity against at least one of the tested pathogens, with an inhibitory zone's diameter varying between 15.0 and 24.0 mm. Two isolates that showed the highest antimicrobial activity were identified as Lactobacillus plantarum CIP 103151 and Lactobacillus plantarum JCM 1149 according to 16S rRNA analysis. In the present study, applying genome shuffling approach significantly enhanced the antibacterial activity of L. plantarum. The initial populations were obtained via ultraviolet irradiation and were treated using the protoplast fusion method. The ideal condition for the production of protoplasts was 15 mg/ml of lysozyme and 10 µg/ml of mutanolysin. After two rounds of fusion, ten recombinants exhibited a significant increase in the inhibition zones versus S. aureus, S. typhimurium, P. aeruginosa, and E. coli, reaching up to 1.34, 1.31, 1.37, and 1.37-fold increase in inhibitory zone respectively. Random Amplified Polymorphic DNA results showed clear differences in DNA banding patterns among the wild strain of L. plantarum CIP 103151 and the three selected shuffled strains using primers 1283 & OPA09. On the other hand, no change was obtained using primers OPD03 neither among the wild strain and the three recombinant strains nor among the three shuffled strains.

Identification of quorum sensing-regulated Vibrio fortis as potential pathogenic bacteria for coral bleaching and the effects on the microbial shift.

Coastal pollution, global warming, ocean acidification, and other reasons lead to the imbalance of the coral reef ecosystem, resulting in the increasingly serious problem of coral degradation. Coral bleaching is often accompanied by structural abnormalities of coral symbiotic microbiota, among which Vibrio is highly concerned. In this study, Vibrio fortis S10-1 (MCCC 1H00104), isolated from sea cucumber, was used for the bacterial infection on coral Seriatopora guttatus and Pocillopora damicornis. The infection of S10-1 led to coral bleaching and a significant reduction of photosynthetic function in coral holobiont, and the pathogenicity of V. fortis was regulated by quorum sensing. Meanwhile, Vibrio infection also caused a shift of coral symbiotic microbial community, with significantly increased abundant Proteobacteria and Actinobacteria and significantly reduced abundant Firmicutes; on genus level, the abundance of Bacillus decreased significantly and the abundance of Rhodococcus, Ralstonia, and Burkholderia-Caballeronia-Paraburkholderia increased significantly; S10-1 infection also significantly impacted the water quality in the micro-ecosystem. In contrast, S10-1 infection showed less effect on the microbial community of the live stone, which reflected that the microbes in the epiphytic environment of the live stone might have a stronger ability of self-regulation; the algal symbionts mainly consisted of Cladocopium sp. and showed no significant effect by the Vibrio infection. This study verified that V. fortis is the primary pathogenic bacterium causing coral bleaching, revealed changes in the microbial community caused by its infection, provided strong evidence for the "bacterial bleaching" hypothesis, and provided an experimental experience for the exploration of the interaction mechanism among microbial communities, especially coral-associated Vibrio in the coral ecosystem, and potential probiotic strategy or QS regulation on further coral disease control.

The bacterial signature offers vision into the machinery of coral fitness across high-latitude coral reef in the South China Sea.

Coral-bacterial interaction is a major driver in coral acclimatization to the stressful environment. 16S rRNA High-throughput sequencing was used to classify the role of different coral reef compartments; sediment, water, and tissue; in the South China Sea (SCS), as well as different locations in shaping the microbial community. The majority of OTUs significantly shifted at impacted sites and indicated distinction in the relative abundance of bacteria compartment/site-wise. Richness and diversity were higher, and more taxa were enriched in the sediment communities. Proteobacteria dominated sediment samples, while Cyanobacteria dominated water samples. Coral tissue showed a shift among different sites with Proteobacteria remaining the dominant Phylum. Moreover, we report a dominance of Chlorobium genus in the healthy coral tissue sample collected from the severely damaged Site B, suggesting a contribution to tolerance and adaptation to the disturbing environment. Thus, revealing the complex functionally diverse microbial patterns associated with biotic and abiotic disturbed coral reefs will deliver understanding of the symbiotic connections and competitive benefit inside the hosts niche and can reveal a measurable footprint of the environmental impacts on coral ecosystems. We hence, urge scientists to draw more attention towards using coral microbiome as a self-sustaining tool in coral restoration.

Rigid, eco-friendly and superhydrophobic SiO2-Polyvinyl alcohol composite sponge for durable oil remediation.

Development of durable and eco-friendly adsorbents for oil remediation is in great demands. However, most of adsorbents were designed to pursue large capabilities while ignored their strength after adsorbing oil, which might cause secondary oil spilling during complex salvage process. Herein, an eco-friendly and superhydrophobic SiO2-modified polyvinyl alcohol composite (H-SiO2-G-PVA) sponge with extraordinary rigid structure after oil adsorption is designed for durable oil remediation. Through a two-step hydrolysis-condensation process including deposition of silica microparticles and introduction of hexadecyltrimethoxysilane (HDTMS), a superhydrophobic H-SiO2-G-PVA sponge has been successfully constructed. The sponge presents stable superhydrophobicity in various complex environments，therefore it efficiently adsorbs oil from water (up to 6 g g-1) and separate surfactant-stabilized water/oil emulsion with high efficiency (>99%). Noticeably, the H-SiO2-G-PVA sponge maintains tough strength (3.5 MPa) after oil adsorption, which ideally overcomes secondary oil spilling problem and endows the sponge with excellent recycling performances (>20 cycles). Meanwhile, the excellent biocompatibility of the sponge (high cell viability of 91.85%) ensures the potential for practical applications. This rigid, eco-friendly oil-adsorbing sponge that achieves stable superhydrophobicity and recyclability, fulfills the application needs for durable oil remediation.

Molecular analysis and anticancer properties of two identified isolates, Fusarium solani and Emericella nidulans isolated from Wady El-Natron soil in Egypt against Caco-2 (ATCC) cell line.

OBJECTIVE: To characterize, identify and investigate the anticancer properties of two new soil fungal isolates, Emericella nidulans and Fusarium solani isolated from Wady El-Natron in Egypt against colon cancer Caco-2 (ATCC) cell line. METHODS: Soil sample was cultured and two strains were chosen for morphological and phenotypical characterization. Partial sequences of the 18s rRNA gene and the internal transcribed spacer region ITS of the two isolates were amplified by PCR. Phylogenetic tree construction and analysis of the resulted multiple sequences from the two fugal isolates were also carried out. In vitro anticancer activity of the two strains was done against colon Caco-2 cancer cell line. Reverse transcription - PCR was carried out to detect level of expression of p53 in Caco-2 cell line. RESULTS: HF.1 displayed morphological and genotypic characteristics most similar to that of Fusarium solani while HF.2 was most similar to Emericella nidulans with high similarity of 99% and 97% respectively. The multiple sequence alignment of the two fungal isolates showed that, the maximum identical conserved domains in the 18s rRNA genes were identified with the nucleotide regions of 51st to 399th base pairs, 88th to 525th base pairs respectively. While those in the ITS genes were identified with the nucleotide regions of 88th to 463rd and 51st to 274th. The two isolates showed IC50 value with (6.24±5.21) and (9.84±0.36) µg/mL) concentrations respectively at 28h. Reverse transcription - PCR indicated that these cells showed high level of expression for p53 mRNA. CONCLUSIONS: The morphology and molecular analysis identified HF.1 and HF.2 to be Fusarium solani and Emericella nidulans; new isolates of anticancer producing fungi from Wady El-Natroon city in Egypt. Treatment with the two isolates caused P53 expression in Caco-2 cell line. These two isolates can be used as an anticancer agents.