Probing Denitrifying Anaerobic Methane Oxidation via Antimicrobial Intervention: Implications for Innovative Wastewater Management.

Methane emissions present a significant environmental challenge in both natural and engineered aquatic environments. Denitrifying anaerobic methane oxidation (N-DAMO) has the potential for application in wastewater treatment plants. However, our understanding of the N-DAMO process is primarily based on studies conducted on environmental samples or enrichment cultures using metagenomic approaches. To gain deeper insights into N-DAMO, we used antimicrobial compounds to study the function and physiology of 'Candidatus Methanoperedens nitroreducens' and 'Candidatus Methylomirabilis oxyfera' in N-DAMO enrichment cultures. We explored the effects of inhibitors and antibiotics and investigated the potential application of N-DAMO in wastewater contaminated with ammonium and heavy metals. Our results showed that 'Ca. M. nitroreducens' was susceptible to puromycin and 2-bromoethanesulfonate, while the novel methanogen inhibitor 3-nitrooxypropanol had no effect on N-DAMO. Furthermore, 'Ca. M. oxyfera' was shown to be susceptible to the particulate methane monooxygenase inhibitor 1,7-octadiyne and a bacteria-suppressing antibiotic cocktail. The N-DAMO activity was not affected by ammonium concentrations below 10 mM. Finally, the N-DAMO community appeared to be remarkably resistant to lead (Pb) but susceptible to nickel (Ni) and cadmium (Cd). This study provides insights into microbial functions in N-DAMO communities, facilitating further investigation of their application in methanogenic, nitrogen-polluted water systems.

Modular Approach to the Functionalization of Polymersomes.

Functionalizing polymersomes remains a challenge due to the limitation in reaction conditions applicable to the chemistry on the surface, hindering their application for selective targeting. In order to overcome this limitation, functionalization can be introduced right before the self-assembly. Here, we have synthesized a library (32 examples) of PEG-b-PS and PEG-b-PDLLA with various functional groups derived from the amine-functionalized polymers, leading to functionally active polymersomes. We show that polymersome formation is possible via the general method with all functionalized groups and that these handles are present on the surface and are able to undergo reactions. Additionally, this methodology provides a general synthetic tool to tailor the functional group of the polymersome right before self-assembly, without limitation on the reaction conditions.

Cyclobutanes in Small-Molecule Drug Candidates.

Cyclobutanes are increasingly used in medicinal chemistry in the search for relevant biological properties. Important characteristics of the cyclobutane ring include its unique puckered structure, longer C-C bond lengths, increased C-C π-character and relative chemical inertness for a highly strained carbocycle. This review will focus on contributions of cyclobutane rings in drug candidates to arrive at favorable properties. Cyclobutanes have been employed for improving multiple factors such as preventing cis/trans-isomerization by replacing alkenes, replacing larger cyclic systems, increasing metabolic stability, directing key pharmacophore groups, inducing conformational restriction, reducing planarity, as aryl isostere and filling hydrophobic pockets.