{"id":1781,"date":"2024-04-25T09:38:26","date_gmt":"2024-04-25T07:38:26","guid":{"rendered":"https:\/\/biophysics.pmfst.unist.hr\/javna-obrana-doktorskog-rada-doktoranda-luke-gujinovica-mag-phys\/"},"modified":"2024-05-06T09:41:02","modified_gmt":"2024-05-06T07:41:02","slug":"javna-obrana-doktorskog-rada-doktoranda-luke-gujinovica-mag-phys","status":"publish","type":"post","link":"https:\/\/biophysics.pmfst.unist.hr\/en\/javna-obrana-doktorskog-rada-doktoranda-luke-gujinovica-mag-phys\/","title":{"rendered":"Javna obrana doktorskog rada doktoranda LUKE GUJINOVI\u0106A, mag. phys."},"content":{"rendered":"\n

OBAVIJEST<\/strong><\/p>\n\n\n\n

Javna obrana doktorskog rada studenta doktorskog studija BIOFIZIKA<\/p>\n\n\n\n

LUKE GUJINOVI\u0106A, mag. phys.<\/h2>\n\n\n\n

pod naslovom<\/p>\n\n\n\n

\u201cADHESION AND DISPERSION DYNAMICS OF MARINE BACTERIA ON A SOLID SUBSTRATE\u201d<\/h2>\n\n\n\n

odr\u017eat \u0107e se u petak, 3. svibnja 2024., u 15:30 sati<\/strong> na Prirodoslovno-matemati\u010dkog fakulteta u Splitu, u amfiteatru A0-1, pred \u010dlanovima Stru\u010dnog povjerenstva:<\/p>\n\n\n\n

    \n
  1. prof. dr. sc. Ante Bilu\u0161i\u0107, <\/strong>Prirodoslovno matemati\u010dki fakultet u Splitu, predsjednik,<\/li>\n\n\n\n
  2. dr. sc. Nelly Henry, <\/strong>Research Director, Laboratoire Jean Perrin, CNRS\/Sorbonne Universit\u00e9, \u010dlanica,<\/li>\n\n\n\n
  3. prof. dr. sc. Marija Ragu\u017e, <\/strong>Medicinski fakultet u Splitu, \u010dlanica.<\/li>\n<\/ol>\n\n\n\n

    Mentor i komentor<\/strong>:<\/p>\n\n\n\n

    prof. dr. sc. Dra\u017een Zanchi<\/strong>  \u2013 MSC laboratory UFR de Physique Faculte des Sciences Universite de Paris Cite i doc. dr. sc. Ivica \u0160amani\u0107  <\/strong>\u2013 Prirodoslovno matemati\u010dki fakultet u Splitu.<\/p>\n\n\n\n

    Pozivaju se svi zainteresirani da prisustvuju obrani doktorskog rada.<\/strong><\/p>\n\n\n\n

    Naslov:  DINAMIKA ADHEZIJE I RASPR\u0160ENJA MORSKE BAKTERIJE NA \u010cVRSTOM SUPSTRATU<\/strong><\/p>\n\n\n\n

    SA\u017dETAK<\/strong>:<\/p>\n\n\n\n

    Morska bakterija Vibrio gigantis<\/em> izolirana je iz Ka\u0161telanskog zaljeva iz ranofaznog prirodnog biofilma te kultivirana. Rezultati su pokazali da je Vibrio gigantis <\/em>prikladna i prilagodljiva modelna vrsta za istra\u017eivanje adhezijske dinamike i razvoja biofilma. NGS analizom pokazana je najve\u0107a relativna prisutnost ove vrste u uzorcima biofilma. Njen predvi\u0111eni genetski potencijal potvrdio je aktivnost u povr\u0161inskoj adheziji, bakterijskom gibanju i kolektivnom osje\u0107anju (engl. quorum sensing) \u2013 bakterijskoj komunikaciji za kolektivno pona\u0161anje. Dinamika adhezije je uspje\u0161no kvantificirana u novodizajniranom eksperimentalnom postavu. Adhezija u stvarnom vremenu je tako\u0111er kvantificirana u dvjema razli\u010ditim geometrijama, ba\u010dvastom spremniku i mikrokanalu, koji su pokazali spontanu adheziju ovisnu o nutrijentima i kisiku, uz naglo i nepovratno odljepljivanje. Nastavljaju\u0107i s eksperimentima evolucije kolonija pod stalnom opskrbom resursima, kolonije su prvo rasle eksponencijalno, ali bi se u kona\u010dnici i raspr\u0161ile s povr\u0161ine. Raspr\u0161enje je bilo istovremeno i kolektivno pri \u010demu su na dnu ostale filamentne bakterije. Pokazano je da je raspr\u0161enje izazvano pri odre\u0111enoj pokrivenosti supstrata, ukazuju\u0107i na va\u017enost koncentracije zalijepljenih bakterija u kontroliranom odzivu na nepovoljne uvjete. Napredovanje fenomena kolektivne disperzije je ispitano mjere\u0107i njegovu ovisnost o poziciji uzdu\u017e mikrofluidnog PDMS kanala, u kontroliranom longitudinalnom laminarnom toku. Konkretno, istovremeno pra\u0107enje dva razli\u010dita polo\u017eaja u kanalu omogu\u0107ilo je izravno promatranje ka\u0161njenja disperzije. Nadalje, 2D pra\u0107enje otkrilo je i transverzalnu i longitudinalnu vremensku ovisnost disperzije, prikazanu kao prostorno-vremenski uzorak u obliku fronte. To je ukazalo da je disperzija doista potaknuta interakcijom izme\u0111u bakterija. \u010cinjenica da je dinamika disperzije neovisna o uzorku rasta kolonija (klasterima) isklju\u010duje kontaktnu i\/ili hidrodinami\u010dku prirodu bakterijske interakcije. Time se zaklju\u010duje da je koordinacija bakterijske disperzije biolo\u0161ke prirode, tj. nalik na komunikaciju quorum sensingom.<\/p>\n\n\n\n

    Title:  ADHESION AND DISPERSION DYNAMICS OF MARINE BACTERIA ON A SOLID SUBSTRATE<\/strong><\/p>\n\n\n\n

    ABSTRACT<\/strong>:<\/p>\n\n\n\n

    The marine bacterium Vibrio gigantis<\/em> was isolated from Ka\u0161tela Bay from wild early-phase biofilm and cultivated. The results showed that Vibrio gigantis<\/em> can be used as an appropriate and versatile model species for adhesion dynamics and biofilm evolution research. NGS analysis confirmed the highest relative abundance of this species inside biofilm samples. Its predicted genetic potential confirmed the activity in surface adhesion, cell motility and quorum sensing \u2013 a bacterial communication for collective behaviour. The adhesion dynamics was successfully quantified in a newly designed experimental setup. Real-time adhesion was also quantified in two different geometries, a barrel-like container and a microchannel, showing a spontaneous nutrient, and oxygen-dependent adhesion, with a sudden and irreversible detachment. Proceeding with the colony evolution experiments under a constant resource supply, the colonies first grew exponentially and eventually dispersed from the surface. Dispersion was simultaneous and collective, leaving filamentous-form bacteria on the bottom. It was shown to be triggered at a certain substrate coverage, indicating the importance of the adhered bacteria concentration for a collective response to unfavourable conditions. The progression of this collective dispersion phenomenon was studied by measuring its dependence on the position along a microfluidic PDMS channel under controlled longitudinal laminar flux. In particular, simultaneous monitoring of two different positions in the channel allowed a direct observation of dispersion delay. Furthermore, 2D monitoring revealed both transversal and longitudinal time dependence of the dispersion, both presented as a front-like space-time pattern. This indicated that dispersion is indeed driven by interaction between bacteria. The fact that the dispersion dynamics is independent of colony growth pattern (clustering) rules out the contact and\/or hydrodynamical nature of bacterial interaction. Thereby, it is concluded that the coordination of bacterial dispersion is of a biological nature, i.e. quorum sensing-like.<\/p>\n","protected":false},"excerpt":{"rendered":"

    OBAVIJEST Javna obrana doktorskog rada studenta doktorskog studija BIOFIZIKA LUKE GUJINOVI\u0106A, mag. phys. pod naslovom \u201cADHESION AND DISPERSION DYNAMICS OF MARINE BACTERIA ON A SOLID SUBSTRATE\u201d odr\u017eat \u0107e se u petak, 3. svibnja 2024., u 15:30 sati na Prirodoslovno-matemati\u010dkog fakulteta u Splitu, u amfiteatru A0-1, pred \u010dlanovima Stru\u010dnog povjerenstva: Mentor i komentor: prof. dr. sc.<\/p>\n","protected":false},"author":1,"featured_media":705,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[26,16],"tags":[],"class_list":["post-1781","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-defences-of-doctoral-theses","category-news-and-updates"],"acf":[],"_links":{"self":[{"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/posts\/1781","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/comments?post=1781"}],"version-history":[{"count":1,"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/posts\/1781\/revisions"}],"predecessor-version":[{"id":1782,"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/posts\/1781\/revisions\/1782"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/media\/705"}],"wp:attachment":[{"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/media?parent=1781"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/categories?post=1781"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/biophysics.pmfst.unist.hr\/en\/wp-json\/wp\/v2\/tags?post=1781"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}