بررسي تاثير تيمار لاكتوكوكوس لاكتيس و بيفيدوباكتريوم بيفيدوم بر بيان ژنهاي مولد آمين هاي بيوژن در سويه هاي استافيلوكوكوس جدا شده از شير

Evaluation of the effects of treatment of Lactococcus lactis and Bifidobacterium bifidum on the expression of biogenic amine-producing genes in Staphylococcus strains isolated from milk

اين مطالعه تاثير باكتريهاي پروبيوتيك لاكتوكوكوس لاكتيس و بيفيدوباكتريوم بيفيدوم را بر بيان ژن مولد آمين هاي بيوژن در استافيلوكوك هاي جدا شده از شير با استفاده از روش هاي استاندارد بررسي نموده است. جداسازي استافيلوكوكوس ها از 100 نمونه شير خام با استفاده از روش هاي استاندارد بيوشيميايي، رنگ آميزي گرم و بررسي توالي 16S rRNA انجام شد. نمونه هاي حاوي اين سويه ها از نظر توليد آمين هاي بيوژن توسط HPLC مورد بررسي قرار گرفتند و وجود ژن هاي هدف توسط MultiplexPCR ﺗﻌﯿﯿﻦ ﺷﺪ. ﺑﺎﮐﺘﺮي ﻫﺎي واﺟﺪ ژن ﻫﺎي ﻫﺪف ﺗﺤﺖ ﺗﯿﻤﺎر ﺑﺎ ﺳﻮﭘﺮﻧﺎﺗﺎﻧﺖ ﻻﮐﺘﻮﮐﻮﮐﻮس ﻻﮐﺘﯿﺲ و ﺑﯿﻔﯿﺪوﺑﺎﮐﺘﺮﯾﻮم ﺑﯿﻔﯿﺪوم ﻗﺮار ﮔﺮﻓﺘﻨﺪ و ﺑﯿﺎن ژن ﻫﺎ ﺑﺎ Real time PCR ﺳﻨﺠﯿﺪه ﺷﺪ. داده ﻫﺎ ﻧﺸﺎن داد ﮐﻪ 60 ﺳﻮﯾﻪ اﺳﺘﺎﻓﯿﻠﻮﮐﻮﮐﻮس ﺟﺪاﺳﺎزي ﺷﺪ ﮐﻪ در ژﻧﻮم 54 ﺳﻮﯾﻪ ژﻧﻬﺎي ﻫﺪف ﺣﻀﻮر داﺷﺘﻨﺪ و در 3 ﻧﻤﻮﻧﻪ ﻣﯿﺰان ﮐﺎدآورﯾﻦ و ﭘﻮﺗﺮﺳﯿﻦ در ﺑﯿﺸﺘﺮﯾﻦ ﺣﺎﻟﺖ ﺧﻮد ﺑﻮد. ﻣﻘﺎدﯾﺮ آﻣﯿﻦ ﻫﺎي ﺑﯿﻮژن در روزﻫﺎي دوم و ﺳﻮم ﺗﯿﻤﺎر ﻧﺴﺒﺖ ﺑﻪ روز اول ﺑﻪ ﺻﻮرت ﻣﻌﻨﯽ داري ﺑﯿﺸﺘﺮ ﺑﻮد )0,001

This study investigated the effect of probiotic bacteria Lactococcus lactis and Bifidobacterium bifidum on the expression of the cadaverine and putrescine producing gene in staphylococci species isolated from milk. Staphylococci were identified and isolated from 100 samples of raw milk using standard biochemical methods, Gram staining and 16srRNA sequencing. Samples containing these strains were examined by HPLC for the production of biogenic amines. The presence of the target genes was determined by MultiplexPCR. Bacteria with target gene were treated with Lactococcus lactis supernatant and Bifidobacterium bifidum and the expression of genes was measured by Real time PCR. The data showed that 60 strains of Staphylococcus were isolated, 54 strains of them had target genes. In three samples the level of the cadaverine and putrescine was higher than others. The levels of biogenic amines in the second and third days were significantly higher than the first day (p <0.001). The MIC results obtained for Staphylococcus bacteria exposed to probiotic bacteria in the samples were 125 μg/ml or 62.5 μg/ml. The results of Real Time PCR reaction showed that the mean reduction in the level of changes in gene expression was statistically significant (p <0.05). This study showed that the use of probiotic bacteria can reduce this bacteria populations and increase the quality of milk by reducing the expression of the biogenic amines-producing genes.