Purification and Antimicrobial Assay of an Antimicrobial Protein from a Biocontrol Bacterium Strain K2-1 against Aquatic Pathogens

[Objective] The aim of this study was to purify an antimicrobial protein from a biocontrol bacterium strain K2-1 and analyze its antimicrobial activity in vitro against some typical aquatic pathogens. [Method] The antimicrobial protein was ob- tained by using ammonium sulfate precipitation and Sephadex chromatography combined with hot water bath. The antimicrobial assay was conducted by means of agar diffusion technique, using Vibrio alginolyticus, Aeromonas hydrophila, Aeromonas. Sobria, Pseudomonas fluorescens, Vibrio Parahaemolyticus, Vibrio har- veyi and Vibrio anguillarum as test bacteria. [Result] Antimicrobial protein APK2 can be derived from fermentation broth of strain K2-1 and purified to the chromatogra- phy pure level by the methods provided, the final yield of the antimicrobial compo- nent is approximately 0.08%. This antimicrobial protein had a strong antimicrobial activity against the growth of most those bacteria. [Conclusion] The results show that APK2 could be a potential alternative to replace chemical antimicrobial agent in the control and prevention of aquatic diseases.

Biogenic synthesis of silver nanoparticles using ginger(Zingiber officinale)extract and their antibacterial properties against aquatic pathogens

With the development of aquaculture, there is an urgent demand for an alternative antibacterial agent to reduce the drug resistance and environmental pollution caused by the abuse of antibiotics. Recently, silver nanoparticles（Ag NPs） have been viewed as a novel type of antimicrobial agents due to their unique advantages. In this study,Ag NPs were biosynthesized with the ginger rhizomes extract. The biosynthesized Ag NPs were characterised by UV–visible spectroscopy, transmission electron microscopy, X-ray diffraction and fourier transform infrared spectroscopy. Furthermore, the antimicrobial activities of the Ag NPs were fully analyzed against six typical aquatic pathogens. The results indicated that the components in ginger extract could function as the chemical reductant to synthesize Ag NPs. Moreover, compared with the Ag NPs synthesized by chemical methods, the biosynthesized Ag NPs were smaller, and had higher stability and antibacterial activity. Therefore, the biosynthesized Ag NPs using ginger extract may have prospective applications in aquaculture.

Reform and Exploration of Integrating"Service Learning"into the Teaching of Pathogenic Biology of Aquatic Animals to Help Rural Revitalization

This paper intends to combine the development trend of the subject,restructure and optimize the course content,and construct the service learning model of Pathogenic Biology of Aquatic Animals for postgraduates.At the same time,through service practice,it is needed to further consolidate curriculum knowledge and skills,stimulate the learning initiative and enthusiasm of postgraduates,expand professional knowledge,improve professional quality,and lay a solid foundation for serving the national rural revitalization strategy in the future.

Construction of Case Database for Postgraduate Course Aquatic Animal Pathogen Biology

As an application instructional course for Aquatic Animal Medicine(AAM),Aquatic Animal Pathogen Biology needs to be guided by a large number of examples and cases,but the current case database construction faces many urgent problems.In view of this,this paper analyzes the characteristics of professional education of AAM postgraduate students.With the goal of cultivating applied personnel that meet the requirements of the times,and the guiding ideology of strengthening the reform of the education model in colleges and universities,and improving the quantity and quality of personnel training,it builds a case database for the course Aquatic Animal Pathogen Biology in accordance with modern postgraduate teaching needs.