Neospora caninum is an intracellular protozoan parasite closely related to Toxoplasma gondii that mainly infects canids as the definitive host and cattle as the intermediate host, resulting in abortion in cattle and leading to financial losses worldwide. Commercial vaccines or drugs are not available for the prevention and treatment of bovine neosporosis. Knowledge about the hallmarks of the immune response to this infection could form the basis of important prevention strategies. The innate immune system first responds to invading parasite and subsequently initiates the appropriate adaptive immune response against this parasite. Upon infection, activation of host pattern-recognition receptors expressed by immune cells triggers the innate immune response. Toll-like receptors, NOD-like receptors, and C-type lectin receptors play key roles in recognizing protozoan parasite. Therefore, we aimed to explore the role of the NLRP3 inflammasome during the acute period of N. caninum infection. In vitro results showed that N. caninum infection of murine bone marrow-derived macrophages activated the NLRP3 inflammasome, accompanied by the release of IL-1β and IL-18, cleavage of caspase-1, and induction of cell death. K+ efflux induced by N. caninum infection participated in the activation of the inflammasome. Infection of mice deficient in NLRP3, ASC, and caspase-1/11 resulted in decreased production of IL-18 and reduced IFN-γ in serum. Elevated numbers of monocytes/macrophages and neutrophils were found at the initial infection site, but they failed to limit N. caninum replication. These findings suggest that the NLRP3 inflammasome is involved in the host response to N. caninum infection at the acute stage and plays an important role in limiting parasite growth, and it may enhance Th1 response by inducing production of IFN-γ. These findings may help devise protocols for controlling neosporosis.

A (salen)­Mn­(III) complex was used as a biomimetic surrogate of the metallocofactor of phenol-oxidizing enzymes, in combination with chiral phosphoric acid relay catalysis, enabling an enantioselective direct oxidative phenol-indole [3 + 2] coupling reaction to access structurally diverse chiral benzofuroindolines. Differing from previous methods that exclusively make use of isolatable quinones or their imines, this system is capable of harnessing transient N-Boc quinone imines, and highlights its synthetic potential with high enantioselectivities, high step and atom economy, benign reaction conditions, and remarkable catalytic turnover for chiral phosphoric acid (CPA) (low to 0.01 mol %; up to 4100 turnover number (TON)).

Inspired by mechanic force induced S–S bridge activation in a protein context, we have developed the first mechanochemical electrophilic C–H sulfenylation of indoles in combination with iodine catalysis. Differing from previous relevant methods that typically necessitate either intrinsically reactive sulfur sources or external forceful conditions but at the expense of atom economy and environmental benignity, our strategy disclosed herein capitalizes on readily available disulfides as sulfenylation reagents promoted by ball milling, thereby rendering rapid synthesis of indolyl sulfides with broad structural diversity under aerobic oxidation and solvent-minimum and metal-free conditions. Moreover, mechanistic studies reveal that the solid and liquid grinding auxiliaries synergistically facilitate this process.

The first regiospecific catalytic intermolecular assembly of 2,2-disubstituted indolines has been developed. This protocol is based on a ligand and directing group free, iron-catalyzed radical [3 + 2] process, allowing efficient coupling of different N-sulfonylanilines with various α-substituted styrenes. Preliminary mechanistic studies elucidated the radical mechanism involving a reactive and versatile anilino radical and the importance of iron complex as a Lewis acid, rendering both the reactivity and regiospecificity of this transformation.

Herein, we present a hemin-catalyzed oxidative phenol-hydrazone [3+3] cycloaddition that accommodates a broad spectrum of N-arylhydrazones, a class of less exploited 1,3-dipoles due to their significant Lewis basicity and weak tendency to undergo 1,2-prototropy to form azomethine imines. It renders expedient assembly of diversely functionalized 1,3,4-oxadiazines with excellent atom and step economy. Preliminary mechanistic studies point to the involvement of a one-electron oxidation pathway, which likely differs from the base-promoted aerobic oxidative scenario.