Antibacterial Effect Of Dithiocyano-methane Against Pathogenic Aeromonas Hydrophila

Aeromonas hydrophila(Ah),as a pathogen with broad infection spectrum and strong pathogenicity,causes serious harm to the development of aquaculture industry and human health.Dithiocyano-methane,which is a kind of organic hydrogen sulfide with strong germicidal and nematode killing ability,has been widely used in industrial water treatment,plant planting and prevention and control of water mildew.During the application of the drug in foshan sanshui platinum aquaculture seed and seedling co.,LTD.,I found that the drug had a good therapeutic effect on pseudomonas fluorescei,which was of great guiding significance to the practice and production of aquaculture enterprises.At present,the bacteriostatic ability of dithiocyano-methane on bacteria has not been reported,and the bacteriostatic mechanism of this drug on bacteria has not been studied.In this paper,the antibacterial activity of dithiocyano-methane against Aeromonas hydrophila and the mechanism of drug action were systematically studied.1.The in vitro bacteriostatic activity of dithiocyano-methane against test bacteria X1 was detected by agar diffusion method,and the minimal inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of dithiocyano-methane against test bacteria were determined by double dilution method and plate coating count.The results showed that the inhibitory zone diameter of this drug on the experimental bacteria X1 was 32±1 mm,and the MIC and MBC were both 1.4648mg/m L,indicating that this drug had a strong inhibitory ability.2.Bacterium from bacteria ultrastructure,cell wall integrity and cell membrane permeability,membrane integrity,respiratory metabolism,nucleic acid and protein synthesis,aspects and related gene expression in a comprehensive description the antibacterial mechanism of methylene double ester thiocyanate,transmission electron microscopy(TEM)shows bacteria somatic cell inclusions leak,plasmolysis.The extracellular alkaline phosphatase(AKP)activity of aeromonas hydrophila increasedsignificantly,indicating that methylene dithiocyanate destroyed the cell wall of aeromonas hydrophila.In aeromonas hydrophila,intracellular electrolytes,nucleic acids,proteins and other macromolecular substances,as intracellular metabolic enzymes,such as straw aminotransferase(AST),alanine aminotransferase(ALT)and lactate dehydrogenase(LDH)also leak out of the cell,indicating that methyl dithiocyanate destroys the cell membrane integrity of the bacteria and increases the membrane permeability.The respiratory inhibition test showed that the respiratory inhibition rate of methylene dithiocyanate on aeromonas hydrophilia was 31.59±5.3%.This drug has an inhibitory effect on the respiratory metabolism of the bacteria,and inhibits the respiratory metabolism of the bacteria by inhibiting the pentose phosphate pathway(HMP).Agarose gel electrophoresis showed that methylene dithiocyanate could affect the amount of genomic DNA synthesis.SDS-PAGE gel electrophoresis showed that dithiocyano-methane could inhibit the synthesis of bacterial protein.q PCR results showed that the expression of asd-1 gene related to cell wall synthesis was up-regulated,and the expression of AHA-3100 gene related to peptidoglycan degradation was up-regulated.The pps A gene expression related to pyruvate was up-regulated.The glt A gene expression related to bacterial tricarboxylic acid cycle pathway was down-regulated.The rec A gene encoding homologous recombinant protein was up-regulated.The expression of gro L gene encoding chaperone protein was up-regulated.These results provide theoretical support for the better use of dithiocyano-methane to exert its bacteriostatic effect.In summary,dithiocyano-methane damages the cell wall and cell membrane integrity of bacteria,increases the cell membrane permeability,and makes nucleic acid,protein and important intracellular metabolic enzymes leak.Simultaneously affects the protein synthesis and the nucleic acid synthesis quantity;Inhibition of the bacterial pentose phosphate pathway(HMP)inhibits the metabolism of bacteria and eventually leads to bacterial death.