The multidrug-resistant Pseudomonas fluorescens strain: a hidden threat in boar semen preservation.

Although the bacterial composition of boar ejaculate has been extensively studied, the bacterial composition of extended boar semen is often overlooked, despite the potential risks these microorganisms may pose to the long-term preservation of extended boar semen at 15-17°C. In this study, we characterized the bacterial community composition of extended semen and discovered that Pseudomonas spp. was the dominant flora. The dominant strains were further isolated and identified as a potential new species in the Pseudomonas fluorescens group and named GXZC strain, which had adverse effects on sperm quality and was better adapted to growth at 17°C. Antimicrobial susceptibility testing showed that the GXZC strain was resistant to all commonly used veterinary antibiotics. Whole-genome sequencing (WGS) and genome annotation revealed the large genetic structure and function [7,253,751 base pairs and 6,790 coding sequences (CDSs)]. Comparative genomic analysis with the closest type strains showed that the GXZC strain predicted more diversity of intrinsic and acquired resistance genes to multi-antimicrobial agents. Taken together, our study highlights a problem associated with the long-term storage of extended boar semen caused by a P. fluorescens group strain with unique biological characteristics. It is essential to develop a new antibacterial solution for the long-term preservation of boar semen.

Selective Synthesis of N-[1,3,5]Triazinyl-α-Ketoamides and N-[1,3,5]Triazinyl-Amides from the Reactions of 2-Amine-[1,3,5]Triazines with Ketones.

In this study, we report a selective approach for synthesizing N-([1,3,5]triazine-2-yl) α-ketoamides and N-([1,3,5]triazine-2-yl) amides from ketones with 2-amino[1,3,5]triazines through oxidation and oxidative C-C bond cleavage reaction, respectively. The transformation proceeds under mild conditions, provides good functional group tolerance and chemoselectivity, and will serve as a valuable tool for the synthesis of bioactive products.

Fitness Trade-Offs in Phage Cocktail-Resistant Salmonella enterica Serovar Enteritidis Results in Increased Antibiotic Susceptibility and Reduced Virulence.

The rapid emergence of phage-resistant bacterial mutants is a major challenge for phage therapy. Phage cocktails have been considered one approach to mitigate this issue. However, the synergistic effect of randomly selected phages in the cocktails is ambiguous. Here, we rationally designed a phage cocktail consisting of four phages that utilize the lipopolysaccharide (LPS) O antigen, the LPS outer core, the LPS inner core, and the outer membrane proteins BtuB and TolC on the Salmonella enterica serovar Enteritidis cell surface as receptors. We demonstrated that the four-phage cocktail could significantly delay the emergence of phage-resistant bacterial mutants compared to the single phage. To investigate the fitness costs associated with phage resistance, we characterized a total of 80 bacterial mutants resistant to a single phage or the four-phage cocktail. We observed that mutants resistant to the four-phage cocktail were more sensitive to several antibiotics than the single-phage-resistant mutants. In addition, all mutants resistant to the four-phage cocktail had significantly reduced virulence compared to wild-type strains. Our mouse model of Salmonella Enteritidis infection also indicated that the four-phage cocktail exhibited an enhanced therapeutic effect. Together, our work demonstrates an efficient strategy to design phage cocktails by combining phages with different bacterial receptors, which can steer the evolution of phage-resistant strains toward clinically exploitable phenotypes. IMPORTANCE The selection pressure of phage promotes bacterial mutation, which results in a fitness cost. Such fitness trade-offs are related to the host receptor of the phage; therefore, we can utilize knowledge of bacterial receptors used by phages as a criterion for designing phage cocktails. Here, we evaluated the efficacy of a phage cocktail made up of phages that target four different receptors on Salmonella Enteritidis through in vivo and in vitro experiments. Importantly, we found that pressure from phage cocktails with different receptors can drive phage-resistant bacterial mutants to evolve in a direction that entails more severe fitness costs, resulting in reduced virulence and increased susceptibility to antibiotics. These findings suggest that phage cocktail therapy using combinations of phages targeting different important receptors (e.g., LPS or the efflux pump AcrAB-TolC) on the host surface can steer the host bacteria toward more detrimental surface mutations than single-phage therapy, resulting in more favorable therapeutic outcomes.

The reaction speed of sports athletes in different state levels / Comparação da velocidade de reação dos esportistas na partida da corrida de cem metros / Comparación de la velocidad de reacción de los deportistas en la partida de la corrida de cien metros

ABSTRACT Introduction: The start of a sprint race is one of its most important stages. The reaction time at the start lays a psychological foundation for normal performance and performance improvement in its next three stages. Objective: To research the reaction time of athletes in the starting stage of the 100-meters sprint race. This helps analyze the internal reaction mechanism of the body, which receives signals and responds to actions. Methods: We use a bibliographical research, experimental comparison, and mathematical statistics to study the starting reaction time of sprinters. Results: The starting reaction time of male and female sprinters was basically at the same level. Conclusion: The starting time of Chinese sprinters needs to be improved. 400-m sprinters, especially, should devote more training to their starting reaction time. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Introdução: A partida é uma etapa importante na corrida de cem metros. A velocidade de reação no início estabelece a base psicológica para o desempenho normal e a melhoria do desempenho nas três fases seguintes. Objetivo: Investigar o tempo de reação de atletas no estágio inicial da corrida de 100 metros rasos. Isso ajudará a analisar o mecanismo de resposta interno do corpo, que recebe sinais e responde a ações. Métodos: Pesquisa bibliográfica com comparação experimental e estatísticas matemáticas para estudar o tempo de reação inicial de corredores. Resultados: O tempo de reação inicial de corredores do sexo feminino ou masculino foi basicamente o mesmo. Conclusões: O tempo de reação inicial dos corredores chineses precisa ser melhorado. Corredores dos 400 metros, especialmente, devem dedicar mais tempo de treinamento ao tempo de reação inicial. Nível de evidência II; Estudos terapêuticos - investigação de resultados de tratamento.

RESUMEN Introducción: La partida es una etapa importante en la corrida de cien metros. La velocidad de reacción en el inicio establece la base psicológica para el desempeño normal y la mejoría del desempeño en las tres fases siguientes. Objetivo: Investigar el tiempo de reacción de atletas en la etapa inicial de la corrida de 100 metros. Esto ayudará a analizar el mecanismo de respuesta interno del cuerpo, que recibe señales y responde a acciones. Métodos: Investigación bibliográfica con comparación experimental y estadísticas matemáticas para estudiar el tiempo de reacción inicial de corredores. Resultados: El tiempo de reacción inicial de corredores del sexo femenino o masculino fue básicamente el mismo. Conclusiones: El tiempo de reacción inicial de los corredores chinos necesita ser mejorado. Corredores de 400 metros, especialmente, deben dedicar más tiempo de entrenamiento al tiempo de reacción inicial. Nivel de evidencia II; Estudios terapéuticos - investigación de resultados de tratamiento.

Catalytic ozonation of bisphenol A in aqueous solution using Mn-Ce/HZSM-5 as catalyst.

Mixed manganese and cerium oxide supported on HZSM-5 were synthesized and used as heterogeneous catalysts for ozonation of bisphenol A (BPA) in aqueous solution. The prepared catalysts of Mn-Ce/HZSM-5 were characterized by X-ray diffraction, scanning electron microscopy and Fourier transform-infrared spectroscopy. The results indicated that Mn-Ce/HZSM-5 exhibits extraordinary catalytic activity for the degradation of BPA. Removal of 89.3% of BPA and 90.4% of total organic carbon (TOC) was achieved in 30 min, compared to non-catalytic ozonation, where only 50.5% BPA and 28.1% TOC removal were reached under the same conditions. Adsorption of BPA on HZSM-5 support and Mn-Ce/HZSM-5 catalysts was negligible. The strong inhibition of BPA removal by tert-butyl alcohol indicated that the attack of hydroxyl radicals was responsible for the improvement of catalytic ozonation. It was observed that at neutral pH, which is near the point of zero charge of the catalyst, the catalytic activity reached its maximum. Increasing the amount of Mn-Ce/HZSM-5 catalyst until it exceeded 3 g/L did not show a strong effect on BPA removal. The catalysts showed high stability and reusability.