BBCC367 is a marine bacterium that is common in coastal areas. It belongs to the
clade, a widespread group in pelagic marine ecosystems. Species of the
clade are regularly used as models to ...understand the evolution and physiological adaptability of generalist bacteria.
BBCC367 comprises two chromosomes and two plasmids. We used gel-free shotgun proteomics to assess its protein expression under 16 different conditions, including stress factors such as elevated temperature, nutrient limitation, high metal concentration, and UVB exposure. Comparison of the different conditions allowed us not only to retrieve almost 70% of the predicted proteins, but also to define three main protein assemblages: 584 essential core proteins, 2,144 facultative accessory proteins and 355 specific unique proteins. While the core proteome mainly exhibited proteins involved in essential functions to sustain life such as DNA, amino acids, carbohydrates, cofactors, vitamins and lipids metabolisms, the accessory and unique proteomes revealed a more specific adaptation with the expression of stress-related proteins, such as DNA repair proteins (accessory proteome), transcription regulators and a significant predominance of transporters (unique proteome). Our study provides insights into how
BBCC367 adapts to environmental changes and copes with diverse stresses.
Organic UV filters are of emerging concern due to their occurrence and persistence in coastal ecosystems. Because marine bacteria are crucial in the major biogeochemical cycles, there is an urgent ...need to understand to what extent these microorganisms are affected by those chemicals. This study deciphers the impact of five common sunscreen UV filters on twenty-seven marine bacteria, combining both photobiology and toxicity analysis on environmentally relevant species. Seven bacteria were sensitive to different organic UV filters at 1000 μg L−1, including octinoxate and oxybenzone. This is the first report demonstrating inhibition of bacterial growth from 100 μg L−1. None of the UV filters showed any toxicity at 1000 μg L−1 on stationary phase cells, demonstrating that physiological state was found to be a key parameter in the bacterial response to UV-filters. Indeed, non-growing bacteria were resistant to UV filters whereas growing cells exhibited UV filter dependent sensitivity. Octinoxate was the most toxic chemical at 1000 μg L−1 on growing cells. Interestingly, photobiology experiments revealed that the toxicity of octinoxate and homosalate decreased after light exposure while the other compounds were not affected. In terms of environmental risk characterization, our results revealed that the increasing use of sun blockers could have detrimental impacts on bacterioplanktonic communities in coastal areas. Our findings contribute to a better understanding of the impact of the most common UV filters on bacterial species and corroborate the importance to consider environmental parameters such as solar radiation in ecotoxicology studies.
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•Five organic UV filters were tested for the first time on 27 marine bacteria.•Seven bacteria demonstrated sensitivity against at least one UV filter.•Octinoxate is the most toxic UV filter, affecting 5 out of 7 sensitive species.•The physiological state plays a key role in the bacterial sensitivity to UV-filters.•Solar radiation modulates UV filters toxicity.
Diel cycle is of enormous biological importance as it imposes daily oscillation in environmental conditions, which temporally structures most ecosystems. Organisms developed biological time-keeping ...mechanisms - circadian clocks - that provide a significant fitness advantage over competitors by optimising the synchronisation of their biological activities. While circadian clocks are ubiquitous in Eukaryotes, they are so far only characterised in Cyanobacteria within Prokaryotes. However, growing evidence suggests that circadian clocks are widespread in the bacterial and archaeal domains. As Prokaryotes are at the heart of crucial environmental processes and are essential to human health, unravelling their time-keeping systems provides numerous applications in medical research, environmental sciences, and biotechnology. In this review, we elaborate on how novel circadian clocks in Prokaryotes offer research and development perspectives. We compare and contrast the different circadian systems in Cyanobacteria and discuss about their evolution and taxonomic distribution. We necessarily provide an updated phylogenetic analysis of bacterial and archaeal species that harbour homologs of the main cyanobacterial clock components. Finally, we elaborate on new potential clock-controlled microorganisms that represent opportunities of ecological and industrial relevance in prokaryotic groups such as anoxygenic photosynthetic bacteria, methanogenic archaea, methanotrophs or sulphate-reducing bacteria.
Growth experiments on the marine bacterium
Vibrio angustum
S14 were conducted under four light conditions using a solar simulator: visible light (V), V + ultraviolet A (UV-A), V + UV-A + UV-B ...radiation, and dark. Growth was inhibited mainly by UV-B and slightly by UV-A. UV-B radiation induced filaments containing multiple genome copies with low cyclobutane pyrimidine dimers. These cells did not show modifications in cellular fatty acid composition in comparison with dark control cultures and decreased in size by division after subsequent incubation in the dark. A large portion of the bacterial population grown under visible light showed an alteration in cellular DNA fluorescence as measured by flow cytometry after SYBR-Green I staining. This alteration was not aggravated by UV-A and was certainly due to a change in DNA topology rather than DNA deterioration because all the cells remained viable and their growth was not impaired. Ecological consequences of these observations are discussed.
Microplastic beads are becoming a common feature on beaches, and there is increasing evidence that such microplastics can become colonised by potential human pathogens. However, whether the ...concentrations and pathogenicity of these pathogens pose a public health risk are still unclear. Therefore, the aim of this study was to determine realistic environmental concentrations of potential pathogens colonising microplastic beads, and quantify the expression of virulence and antimicrobial resistance genes (ARGs). Microplastic beads were collected from beaches and a culture-dependent approach was used to determine the concentrations of seven target bacteria (Campylobacter spp.; E. coli; intestinal enterococci; Klebsiella spp.; Pseudomonas aeruginosa; Salmonella spp.; Vibrio spp.). All seven target bacteria were detected without the need for a pre-enrichment step; urban sites had higher bacterial concentrations, whilst polymer type had no influence on bacterial concentrations. Klebsiella was the most abundant target bacteria and possessed virulence and ARGs, some of which were present on plasmids from other species, and showed pathogenicity in a Galleria melonella infection model. Our findings demonstrate how pathogen colonised microplastic beads can pose a heightened public health risk at the beach, and highlights the urgency for improved monitoring and enforcement of regulations on the release of microplastics into the environment.
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•Potential pathogens detected without the need for a pre-enrichment step.•Klebsiella had ARG and virulence genes, some on plasmids from other species.•Klebsiella isolates showed pathogenicity in a G. mellonella model of infection.
The widespread use of plastic has resulted in the accumulation of plastic waste across a range of sizes, notably including microplastics (MPs). The introduction of MPs into aquatic ecosystems can ...lead to the contamination of organisms, mainly fish. This study reports for the first time a quantitative and qualitative analysis conducted on the abundance of MPs encountered in water and sediment of milkfish aquaculture ponds in Gresik, East Java, Indonesia. Water and sediment samples were collected at three stations between February to April 2021. The abundance of MPs was analyzed through the application of one-way ANOVA tests and Pearson's correlation analysis. The results identified four types of MPs: fragments, fibers, films, and pellets. The highest abundance of MPs in both water (10.40 particle/L) and sediment samples (1.15 particle/g) was observed in March. The predominant MPs size in the water samples is 100–500 μm, while it is below 100 μm in the sediment. The color of the MPs varied across eight colors: black, purple, red, blue, yellow, pink, green, and transparent. The identification of MPs polymers was found to be polypropylene (PP), Polyurethane (PU), Polycarbonate (PC), Polyethylene terephthalate (PETE), High-density polyethylene (HDPE), and low-density polyethylene (LDPE). The presence of MPs in the water column and sediments was correlated with human activities around the ponds. Hence, the abundance of MPs is a source of pollution that has the potential to damage the nutritional quality of farmed milkfish. This study provides important information for the local governments to develop waste management policies for a cleaner environment and improved human health.
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•First report about microplastics contamination in aquaculture-rich regions•Indonesia, mainly Gresik is the second largest world milky fish supply just after China.•More than 628 mediums to large-scale industries (food, textile, garment, etc.) operated in Gresik.•Suffers from local and transboundary problems, lack of responsibility and inaction•Further research needed to develop an effective approach to solve the problem
Marine plastic pollution is rapidly colonized by a biofilm of microorganisms associated with the control of biogeochemical cycles, plastic biodegradation, and potentially pathogenic activities. An ...extensive number of studies have described the taxonomic composition of this biofilm, referred to as the 'plastisphere', and previous reviews have reported on the influence of location, plastic type, and plastic-biodegradation ability on plastisphere formation. However, few studies have investigated the metabolic activity of this complex biofilm and how microbial pathogenicity and bioremediation could be regulated in this ecosystem. In this review, we highlight the understudied molecular and abiotic factors influencing plastisphere formation and microbial functioning beyond taxonomic description. In this context, we critically discuss the impacts of (i) organism-organism interaction, (ii) microbial cell wall composition, and (iii) commonly encountered plastic-bound co-pollutants (heavy metals, persistent organic pollutants, UV filters). For the first time, we review the anticipated impact of lipophilic organic UV-filters - found in plastic additives and sunscreens - on the plastisphere due to their reported affinity for plastics, persistence, and co-location at high concentrations in touristic coastal environments. Herein, we integrate the findings of 34 global studies exploring plastisphere composition, 35 studies quantifying co-pollutant concentrations, and draw upon 52 studies of cell -cell and -substrate interaction to deduce the inferred, yet still unknown, metabolic interactions within this niche. Finally, we provide novel future directions for the advancement of functional plastisphere research applying advanced molecular tools to new, and appropriate research questions.
Data was compiled from 97 plastispheres across 34 different studies and an additional 87 studies relating to the impacts of plastisphere components on microbial species.
The biotic and abiotic factors influencing microbial adhesion to different plastic polymers, including cell wall composition, and plastisphere location are considered.
The impacts of heavy metals and organic co-pollutants - and for the first time, organic UV-filters - on plastisphere formation and function are reviewed and discussed.
A change in direction from novel research questions to the use of state-of-the-art methodologies are recommended for the advancement of functional plastisphere research.
Despite the considerable volume of literature describing the individual effects of temperature or UV light on aquatic bacteria, little is known about their combined effects. The current study was ...conducted to learn about the effects of growth temperature and duration of starvation on the response of a marine bacterium,
Sphingopyxis alaskensis to UV-B or simulated solar radiation. Cells grown at 12
°C or 24
°C, and harvested at early or late stationary phase, were exposed to UV-B or simulated solar radiation (>290
nm). The predominant forms of UV-induced DNA damage, namely cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts (6-4PPs), were quantified using a HPLC–mass spectrometry. While the commonly accepted view that DNA damage induced by UV-B radiation is temperature-independent, we observed in
S. alaskensis that the yield of photoproducts for 12
°C was generally lower than for cells grown at 24
°C. The relative distribution of DNA photoproducts also varied with growth temperature, with an increased formation of TC 6-4PP for late compared to early stationary phase cells. In contrast, with the exception of cultures grown at 12
°C exposed to simulated solar radiation, the duration of stationary phase had no effect on total photoproduct formation. Collectively, these data indicate that growth temperature has more effect than duration of starvation on the formation of photoproducts in
S. alaskensis.
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