ÿþ<HTML><HEAD><TITLE>25º Congresso Brasileiro de Microbiologia </TITLE><link rel=STYLESHEET type=text/css href=css.css></HEAD><BODY aLink=#ff0000 bgColor=#FFFFFF leftMargin=0 link=#000000 text=#000000 topMargin=0 vLink=#000000 marginheight=0 marginwidth=0><table align=center width=700 cellpadding=0 cellspacing=0><tr><td align=left bgcolor=#cccccc valign=top width=550><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=3><font size=1>25º Congresso Brasileiro de Microbiologia </font></font></strong><font face=Verdana size=1><b><br></b></font><font face=Verdana, Arial,Helvetica, sans-serif size=1><strong> </strong></font></font></td><td align=right bgcolor=#cccccc valign=top width=150><font face=arial size=2><strong><font face=Verdana, Arial, Helvetica, sans-serif size=1><font size=1>ResumoID:1981-1</font></em></font></strong></font></td></tr><tr><td colspan=2><br><br><table align=center width=700><tr><td>Área: <b>Microbiologia de Alimentos ( Divisão K )</b><p align=justify><strong>PRESENCE OF <SPAN STYLE="FONT-STYLE: ITALIC;">LACTOBACILLUS SAKEI </SPAN>AND BACTERIOCIN GENE EXPRESSION IN SAMPLES TAKEN FROM HUMAN GASTROINTESTINAL TRACT</strong></p><p align=justify><b><u>Martha Lissete Villarreal Morales </u></b> (<i>WUR</i>); <b>Bernadette Dora Gombossy de Melo Franco </b> (<i>FCF-USP</i>); <b>Susana Marta Isay Saad </b> (<i>FCF-USP</i>); <b>Erwin G Zoetendal </b> (<i>WUR</i>)<br><br></p><b><font size=2>Resumo</font></b><p align=justify class=tres><font size=2> <!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:-1610611985 1073750139 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} .MsoPapDefault {mso-style-type:export-only; margin-bottom:10.0pt; line-height:115%;} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 70.85pt 70.85pt 70.85pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> <div style="text-align: justify;"><span style="font-style: italic;">Lactobacillus sakei</span> is commonly associated with fermented foods, both animal and vegetable. This species has also been shown to be a transient member of the human gastrointestinal microbiota. As many other lactic acid bacteria, certain <span style="font-style: italic;">L. sakei </span>strains produce antimicrobial substances such as bacteriocins, which play a crucial role in meat preservation and fermentation towards pathogenic or spoilage bacteria. It has been suggested that the production of bacteriocins by probiotic strains might contribute for the resistance of humans to gastrointestinal colonization by pathogens. However, our knowledge about in vivo bacteriocin gene expression in the gastrointestinal tract (GIT) is limited. This work aimed to link the presence of <span style="font-style: italic;">L. sakei</span> to the production of bacteriocins in the GIT. A qualitative and quantitative analysis of the bacterial community in fecal samples from 14 healthy volunteers was carried out using 16S rRNA and sakacin gene-specific qPCR, focusing on the lactobacilli community and on <span style="font-style: italic;">L. sakei</span>. <span style="font-style: italic;">L. sakei</span> was detected in 9 of 14 individuals sampled (64.3%), regardless of their diet, pointing out that it can persist in the colon as a normal inhabitant of the GIT. <span style="font-style: italic;">L. sakei </span>was present at 10<sup>5</sup> and 10<sup>6</sup> gene copy/g of feces, representing between 0.1 to 11.4% of total lactobacilli community in the positive samples. Strain <span style="font-style: italic;">L. sakei</span> 2a, isolated at São Paulo University and well known as bacteriocin producer against <span style="font-style: italic;">Listeria monocytogenes</span> and <span style="font-style: italic;">Staphylococcus aureus</span>, was used as a model strain to develop a Reverse Transcription-quantitative PCR (RT-qPCR) method to monitor sakacin gene expression. Monitoring <span style="font-style: italic;">L. sakei</span> 2a gene expression <span style="font-style: italic;">in vitro</span> revealed the concomitant production of two sakacins by <span style="font-style: italic;">L. sakei</span> 2a: sakacin P and sakacin Q. The genes that encode for both bacteriocins were especially expressed during the exponential growth phase in MRS medium. The sakacin P and Q expression <span style="font-style: italic;">in situ</span> in the GIT were just below the detection limit of the RT-qPCR assay. Whether this was due to the low numbers of <span style="font-style: italic;">L. sakei</span>, its growth phase in feces or other factors remains to be determined in the near future.<br>Financial support: CAPES, WUR<br>Key words: <span style="font-style: italic;">Lactobacillus sakei, </span>bacteriocins, Reverse Transcription-quantitative PCR, gene expression<br><br><br></div> </font></p><br><b>Palavras-chave: </b>&nbsp;Bacteriocins, Gene expression, Human gastrointestinal microbiota, Lactobacillus sakei, Reverse Transcription-quantitative PCR</td></tr></table></tr></td></table></body></html>