Search Results (4)

The description of the organization of microorganisms in terms of emergent “social” interactions has long been a fascinating and challenging subject, in both biology and sociology. In these organisms, the role of the individual is far less dominant than that of the community, which operates as a sort of superorganism. The coordination is achieved through a communication mechanism known as quorum sensing. Quorum sensing coordinates and regulates various biological aspects of a microbial community, such as the expression of pathogenicity factors, biofilm formation, and the production of secondary metabolites, among others. These processes rely on the coordinated behavior of the entire bacterial population, enabling them to adapt and thrive withing a specific ecological niche under its unique biological, physical and chemical conditions. Finally, quorum sensing also allows the community to control the development of potentially harmful individuals, thus preserving the cooperativeness of the community. This study uses an agent-based quorum sensing model to explore the relationship between metabolic functions and social behavior in bacteria. In particular, we identify two metabolic parameters whose variations provide a broad panorama of possible social characteristics. Furthermore, the proposed QS model allows us to reproduce, at least qualitatively, some experimental results regarding the competition between some strains with different social characteristics. Finally, we examine how an ideal polyculture responds to variations in the metabolic characteristics of its components. Specifically, we identify a particularly stable condition in which the components cooperate to maximize the overall health of the colony. We refer to this state as resonance for life. Full article

Traditional aquaculture can cause serious environmental pollution. Biofilm and biofloc technology have the potential to limit aquaculture pollution. An outdoor experiment was conducted to evaluate the combined effects of eco-substrates and carbon addition on water quality, fish performance and nutrient budgets in the pond polyculture system. In the treatment group, the total ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, and total nitrogen of the water were significantly lower compared to the control group (p < 0.05). The growth performance of H. molitrix and A. nobilis, including the final individual weight, specific growth rate, weight gain rate, total production and net production, was significantly higher in the treatment groups compared to the control (p < 0.05), while there was no significant difference in those of C. carpio between the two groups. Feed was the main N (>92%) and P (>95%) input during the experiment. Comprehensive accumulation was the main N (>58%) and P (>69%) output. The N and P feed input and comprehensive accumulation output declined in the treatment group. The N utilization efficiency in the experimental group increased slightly (p > 0.05), while the P utilization efficiency in the experimental group was significantly higher compared to the control (p < 0.05). Therefore, the application of eco-substrates and carbon addition can increase water quality, improve fish growth, and promote nutrient utilization efficiency in pond polyculture systems. Full article

Environmental problems associated with marine pollution and climate warming create favorable conditions for the penetration and survival of pathogenic bacteria in marine ecosystems. These microorganisms have interspecific competitive interactions with marine bacteria. Co-culture, as an important research strategy that mimics the natural environment of bacteria, can activate silent genes or clusters through interspecies interactions. The authors used modern biotechnology of co-cultivation to dynamically study intercellular interactions between different taxa of bacteria—pathogenic enterobacteria Yersinia pseudotuberculosis and Listeria monocytogenes and saprotrophic marine bacteria Bacillus sp. and Pseudomonas japonica isolated in summer from the coastal waters of the recreational areas of the Sea of Japan. The results of the experiments showed that during the formation of polycultural biofilms, horizontal transfer of genes encoding some pathogenicity factors from Y. pseudotuberculosis and L. monocytogenes to marine saprotrophic bacteria with different secretion systems is possible. It was previously thought that this was largely prevented by the type VI secretion system (T6SS) found in marine saprotrophic bacteria. The authors showed for the first time the ability of marine bacteria Bacillus sp. and P. japonica to biofilm formation with pathogenic enterobacteria Y. pseudotuberculosis and L. monocytogenes, saprophytic bacteria with type III secretion system (T3SS). For the first time, a marine saprotrophic strain of Bacillus sp. Revealed manifestations of hyaluronidase, proteolytic and hemolytic activity after cultivation in a polycultural biofilm with listeria. Saprotrophic marine bacteria that have acquired virulence factors from pathogenic enterobacteria, including antibiotic resistance genes, could potentially play a role in altering the biological properties of other members of the marine microbial community. In addition, given the possible interdomain nature of intercellular gene translocation, acquired virulence factors can be transferred to marine unicellular and multicellular eukaryotes. The results obtained contribute to the paradigm of the epidemiological significance and potential danger of anthropogenic pollution of marine ecosystems, which creates serious problems for public health and the development of marine culture as an important area of economic activity in coastal regions. Full article

Floating wetland islands (FWI) are considered nature-based solutions with great potential to promote several ecosystem services, such as biodiversity and water quality enhancement through phytoremediation processes. To our knowledge, the present work is the first to scientifically document the in-situ establishment of an FWI in a seawater port marina. The establishment and performance of a cork floating platform with a polyculture (Sarcocornia perennis, Juncus maritimus, Phragmites australis, Halimione portulacoides, Spartina maritima, Limonium vulgare) was evaluated. The diversity of organisms present in the FWI was undertaken based on the macrofauna assessment, taking into consideration marine water characterization, with a focus on hydrocarbons. Microbial communities were assessed based on metabarcoding approach to study 16S rRNA gene from environmental DNA retrieved from biofilm (from the planting media), marine biofouling (from the submerged platform) and surface marina water. S. perennis was the species with the highest survival rate and growth. The structure of the microbial community showed clear differences between those established in the FWI and those in the surrounding water, showing the presence of some bacterial groups that can be relevant for bioremediation processes (e.g., Saprospiraceae family). Concerning the macrofauna analysis, Mytilus sp. was the predominant taxa. To be of relevance, total petroleum hydrocarbons were detected at the marina up to ca. 6 mg/L. This study gives new insights into broadening FWI application to the saline environments of port marinas and to supporting a management strategy to promote several ecosystem services such biodiversity, species habitat, water quality enhancement and added aesthetic value to the marina landscape. Full article