Antimicrobial effect of cinnamic aldehyde against E.coli O157:H7
To investigate whether the growth-inhibiting effect of cinnamic aldehyde on E.coli O157:H7 is attributable to bacteriostatic or bacteriocidal activity, viable cells were counted during the culture in LB media containing the purified cinnamic aldehyde, viable counts increased from 4.9×10 cfu ml of the initial counts to 4.7×10 cfu ml at
37℃ for 12h of cultivation. No significant changes in the viable counts were observed in the presence of 250μg ml of the substance during the culture time.
However, addition of 500μg ml of the substance in the media resulted in a dramatic decrease in the viable counts, which was 1.0×10 cfu ml after 12h of incubation. In the presence of 1000μg ml, all the cells were killed after 2h of incubation. These results suggest that the antimicrobial activity of cinnamic aldehyde is bacteriocidal. The cells treated with 1000μg ml of the purified cinnamic aldehyde at 37℃ for 2h were observed on a scanning electron micro-scope (fig.2).
Non-treated cells showed a smooth surface but the treated cells were severely damaged and destructed in the surface structure. Antimicrobial mechanisms of natural compounds found in herbs or spices have been discussed (Brul and coote,1999 ).thymol and carvacrol have been reported to posscss inhibitory effects the growth of enteric bacteria (E.coli O157:H7 and salmonella typhimurium ) at a similar concentration as show above. They were proposed to have prominent outer membrane disinte-gration and increased the permeablility of ATP through cytoplasmic membrane. However, trans-cinnamic alde-hyde exhibited outer membrane disintegrating activity nor depletion of intracellular ATP (Helander et al.,1998).
- 北北Lv 72 0 年前最佳解答
肉桂baldheaded反對E.coli O157︰要調查的H7的抗菌效應， 是否這抑制發展cinnamic aldehyde對E.coli的影響O157︰H7可歸因於bacteriostatic或者殺細菌活動， 可行的小屋被用磅因在文化期間算為包含被淨化的cinnamic aldehyde的媒介， 可行的計數在37從對4.7 0 cfu ml的最初計數的4.9 0 cfu ml增加嗎？ 對於在農地工作的12 h來說。 沒有顯著的在可行的數字方面的變化在文化時間期間在這種物質的250 ml的情況下被觀察。但是， 這種物質的500 ml的增加在媒介裡導致在可行的數字方面的戲劇性的減少，這是1.0 0 cfu ml， 孕育的12 h。當著1000 ml，的全部細胞殺死在孕育2 h之後。這些結果表明cinnamic aldehyde的抗菌活動是殺細菌的。 在37用被淨化的cinnamic aldehyde的1000 ml處理的小屋嗎？ 對於2 h來說被在掃描電子微機會上觀察(無花果樹。 2). 非治療細胞顯示一順利表面個治療的細胞嚴重損壞並且在表層架構內自毀。在藥草或者香料裡找到的自然的化合物的抗菌機製已經被討論(瘤狀花紋和coote，1999) .thymol和carvacrol已經被報告擁有禁止的效應enteric細菌(E.coli O157︰H7和typhimurium 沙門氏菌)的發展 在相似的集中作為演出在上面。他們被提議有突出的外部膜瓦解並且透過細胞質的膜增加ATP 的滲透性。 不過，展覽的橫穿肉桂濃啤酒海德既不瓦解活動的外部膜也不耗盡的細胞內ATP (霍蘭德et al.， 1998).