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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. [ABSTRACT FROM AUTHOR]

An objective assessment of nasal breathing is currently insufficiently achievable. The application of computational fluid dynamics for this purpose is increasingly gaining attention. However, the suggested specific frameworks can differ considerably. To the best of our knowledge, there is not yet a widely accepted clinical usage of computational fluid dynamics. In this article, selected aspects are addressed that might be crucial for future development and possible implementation of computational fluid dynamics in rhinology. [ABSTRACT FROM AUTHOR]

We report on the synthesis and characterization of a series of (mostly) air‐stable diorganyl bis(pyridylimino) isoindolide (BPI) aluminum complexes and their chemistry upon visible‐light excitation. The redox non‐innocent BPI pincer ligand allows for efficient charge transfer homolytic processes of the title compounds. This makes them a universal platform for the generation of carbon‐centered radicals. The photo‐induced homolytic cleavage of the Al−C bonds was investigated by means of stationary and transient UV/Vis spectroscopy, spin trapping experiments, as well as EPR and NMR spectroscopy. The experimental findings were supported by quantum chemical calculations. Reactivity studies enabled the utilization of the aluminum complexes as reactants in tin‐free Giese‐type reactions and carbonyl alkylations under ambient conditions, which both indicated radical‐polar crossover behavior. A deeper understanding of the physical fundamentals and photochemical process was provided, furnishing in turn a new strategy to control the reactivity of bench‐stable aluminum organometallics. [ABSTRACT FROM AUTHOR]

Wir berichten über die Synthese und Charakterisierung einer Reihe von weitgehend luftstabilen Diorganyl‐bis(pyridylimino)isoindolid(BPI)−Aluminiumkomplexen und deren Reaktivität durch elektronische Anregung mittels sichtbarem Licht. Der redox‐aktive, "nicht‐unschuldige" BPI‐Pinzettenligand ermöglicht eine effiziente Charge‐Transfer‐Homolyse der Al−C‐Bindung. Dadurch dienen die vorgestellten Verbindungen als Ausgangsmaterialien für die Generierung von kohlenstoffzentrierten Radikalen. Die photo‐induzierte homolytische Spaltung der Al−C‐Bindung wurde mittels stationärer und transienter UV/Vis‐Spektroskopie, Abfangexperimenten der entsprechenden Radikale, sowie EPR‐ und NMR‐Spektroskopie analysiert und zudem mithilfe von quantenchemischen Rechnungen untersucht. Studien zur Reaktivität der entsprechenden Aluminiumkomplexe ermöglichten deren Nutzung als Reagenzien in Giese‐artigen Reaktionen und der Alkylierung von organischen Carbonylverbindungen, wobei Hinweise auf einen Wechsel von radikalischen zu polaren Mechanismen (radical‐polar‐crossover) gefunden wurden. Durch diese Arbeit wurde ein vertieftes Verständnis der physikalischen Hintergründe und der ablaufenden photochemischen Prozesse generiert, wodurch eine neue Strategie der Reaktionskontrolle von luftstabilen Organometallverbindungen des Aluminiums etabliert wurde. [ABSTRACT FROM AUTHOR]

The 2010 Deepwater Horizon (DwH) Oil spill released an enormous volume of oil into the Gulf of Mexico (GoM), prompting the widespread use of chemical dispersants like Corexit® EC9500A. The ecological consequences of this treatment, especially when combined with natural factors such as sunlight, remain unexplored in the context of marine bacterial communities' dynamics. To address this knowledge gap, our study employed a unique metaproteomic approach, investigating the combined effects of sunlight, crude Macondo surrogate oil, and Corexit on GoM microbiome across different mesocosms. Exposure to oil and/or Corexit caused a marked change in community composition, with a decrease in taxonomic diversity relative to controls in only 24 hours. Hydrocarbon (HC) degraders, particularly those more tolerant to Corexit and phototoxic properties of crude oil and/or Corexit, proliferated at the expense of more sensitive taxa. Solar radiation exacerbated these effects in most taxa. We demonstrated that sunlight increased the dispersant's toxicity, impacting on community structure and functioning. These functional changes were primarily directed by oxidative stress with upregulated proteins and enzymes involved in protein turnover, general stress response, DNA replication and repair, chromosome condensation, and cell division. These factors were more abundant in chemically treated conditions, especially in the presence of Corexit compared to controls. Oil treatment significantly enhanced the relative abundance of Alteromonas, an oil-degrading Gammaproteobacteria. In combined oil-Corexit treatments, the majority of identified protein functions were assigned to Alteromonas, with strongly expressed proteins involved in membrane transport, motility, carbon and amino acid metabolism and cellular defense mechanisms. Marinomonas, one of the most active genera in dark conditions, was absent from the light treatment. Numerous metabolic pathways and HC-degrading genes provided insights into bacterial community adaptation to oil spills. Key enzymes of the glyoxylate bypass, enriched in contaminant-containing treatments, were predominantly associated with Rhodobacterales and Alteromonadales. Several proteins related to outer membrane transport, photosynthesis, and nutrient metabolisms were characterized, allowing predictions of the various treatments on biogeochemical cycles. The study also presents novel perspectives for future oil spill clean-up processes. [ABSTRACT FROM AUTHOR]