The biological effects of UV radiation of different wavelengths (UVA, UVB and UVC) were assessed in nine bacterial isolates displaying different UV sensitivities. Biological effects (survival and activity) and molecular markers of oxidative stress [DNA strand breakage (DSB), generation of reactive oxygen species (ROS), oxidative damage to proteins and lipids, and the activity of antioxidant enzymes catalase and superoxide dismutase] were quantified and statistically analyzed in order to identify the major determinants of cell inactivation under the different spectral regions. Survival and activity followed a clear wavelength dependence, being highest under UVA and lowest under UVC. The generation of ROS, as well as protein and lipid oxidation, followed the same pattern. DNA damage (DSB) showed the inverse trend. Multiple stepwise regression analysis revealed that survival under UVA, UVB and UVC wavelengths was best explained by DSB, oxidative damage to lipids, and intracellular ROS levels, respectively.

Aging is characterized by the progressive decline of biochemical and physiological function in an individual. Consequently, aging is a major risk factor for diseases like cancer, obesity, and type 2 diabetes. The cellular and molecular mechanisms of aging are not well understood, nor is the relationship between aging and the onset of diseases. One of the hallmarks of aging is a decrease in cellular proteome homeostasis, allowing abnormal proteins to accumulate. This phenomenon is observed in both eukaryotes and prokaryotes, suggesting that the underlying molecular processes are evolutionarily conserved. Similar protein aggregation occurs in the pathogenesis of diseases like Alzheimer's and Parkinson's. Further, protein posttranslational modifications (PTMs), either spontaneous or physiological/pathological, are emerging as important markers of aging and aging-related diseases, though clear causality has not yet been firmly established. This review presents an overview of the interplay of PTMs in aging-associated molecular processes in eukaryotic aging models. Understanding PTM roles in aging could facilitate targeted therapies or interventions for age-related diseases. In addition, the study of PTMs in prokaryotes is highlighted, revealing the potential of simple prokaryotic models to uncover complex aging-associated molecular processes in the emerging field of microbiogerontology.

Aging is associated with the accumulation of cellular damage over the course of a lifetime. This process is promoted in large part by reactive oxygen species (ROS) generated via cellular metabolic and respiratory pathways. Pharmacological, nonpharmacological, and genetic interventions have been used to target cellular and mitochondrial networks in an effort to decipher aging and age-related disorders. While ROS historically have been viewed as a detrimental byproduct of normal metabolism and associated with several pathologies, recent research has revealed a more complex and beneficial role of ROS in regulating metabolism, development, and lifespan. In this review, we summarize the recent advances in ROS research, focusing on both the beneficial and harmful roles of ROS, many of which are conserved across species from bacteria to humans, in various aspects of cellular physiology. These studies provide a new context for our understanding of the parts ROS play in health and disease. Moreover, we highlight the utility of bacterial models to elucidate the molecular pathways by which ROS mediate aging and aging-related diseases.

Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

Lipids are fundamental building blocks of all cells and play important roles in the pathogenesis of different diseases, including inflammation, autoimmune disease, cancer, and neurodegeneration. The lipid composition of different organelles can vary substantially from cell to cell, but increasing evidence demonstrates that lipids become organised specifically in each compartment, and this organisation is essential for regulating cell function. For example, lipid microdomains in the plasma membrane, known as lipid rafts, are platforms for concentrating protein receptors and can influence intra-cellular signalling. Lipid organisation is tightly regulated and can be observed across different model organisms, including bacteria, yeast, Drosophila, and Caenorhabditis elegans, suggesting that lipid organisation is evolutionarily conserved. In this review, we summarise the importance and function of specific lipid domains in main cellular organelles and discuss recent advances that investigate how these specific and highly regulated structures contribute to diverse biological processes.

No abstract

Graphical Abstract

The effects of UV radiation (UVR) on estuarine bacterioneuston and bacterioplankton were assessed in microcosm experiments. Bacterial abundance and DNA synthesis were more affected in bacterioplankton. Protein synthesis was more inhibited in bacterioneuston. Community analysis indicated that UVR has the potential to select resistant bacteria (e.g., Gammaproteobacteria), particularly abundant in bacterioneuston. Global changes over the next decades are expected to increase the exposure of aquatic organisms to damaging UV wavelengths, particularly UV-B (280 to 320 nm), with far-reaching ecological consequences (5). Therefore, a thorough understanding of the effects of UV radiation (UVR) on the diversity and function of bacterial communities, key players in nutrient cycling in aquatic ecosystems, is necessary.The effects of UV-B on aquatic organisms depend on the dose of harmful radiation to which they are exposed, which is, in turn, determined by the positioning of the organism in the water column (19). The surface microlayer (SML) represents a unique microbial niche in which the bacterial community (bacterioneuston) is exposed to high doses of solar UVR (2). The higher abundances of microorganisms in the SML than in underlying waters (UW) (e.g., 1) could indicate that bacterioneuston may have adapted to this "extreme environment," making it an interesting model system for the assessment of UV effects on aquatic organisms by testing the hypothesis that bacterioneuston and bacterioplankton respond differently (in terms of abundance, activity, and structural and functional diversity) to UV-B radiation.Sampling and experimental setup. Samples from the SML and UW were collected in triplicate (n ϭ 9) from an estuarine system (Ria de Aveiro, Portugal, latitude 40°38=N, longitude 08°46=N) on three consecutive days in June 2008. Samples were collected around noon, with a clear sky, minimum wind (Ͻ2 m s Ϫ1 ), and solar radiation levels ranging from 30 to 35 kJ m Ϫ2 (climetua. fis.ua.pt/legacy/main/current_monitor/cesamet.htm). Water properties of the original samples are presented as supplemental material. Bacterioneuston was sampled with glass plates (9). Samples from underlying water were taken at a depth of 20 cm. A total of three irradiation experiments (one on each day), with triplicate subsamples, were conducted using unfiltered water samples, since