<p>U ovom radu su izolovani specifičn<em>i&nbsp; Bordetella bronchiseptica</em>&nbsp; bakteriofagi iz iz<br />priodne sredine koji pripadaju familiji&nbsp; <em>Siphoviridae</em>. Bakteriofagi su&nbsp; okarakterisani u<br />cilju razmatranja njihove uloge u lizogenoj konverziji bakterije i mogućnosti<br />primene u kontroli vrste&nbsp;<em> B. bronchiseptica</em>. U tu svrhu ispitivane su morfolo&scaron;ke<br />karakteristike odabranih faga, litički&nbsp; spektar faga, i karakteristike genoma i proteina<br />faga. Takođe, ispitivana je i stabilnost faga u različitim uslovima sredine, njihova<br />litička efikasnost i efekat na formiranje i vec formirani biofilm. U radu je ispitana i<br />uloga faga u produkciji biofilma,&nbsp; rezistenciji na antibiotike, procesu hemolize i<br />pokretljivosti kod vrste&nbsp; <em>B. bronchiseptica</em>.&nbsp; Rezultati ovog rada jasno ukazuju na<br />ulogu faga u lizogenoj konverziji vrste&nbsp;<em> B.&nbsp; bronchiseptica</em>&nbsp; kao&nbsp; i mogućnost njihove<br />primene, uz određene modifikacije, kao anti-<em>B.bronchiseptica</em> agenasa.</p> / <p>In this paper <em>Bordetella bronchiseptica</em> specific phages belonging to family <em>Siphoviridae</em> were isolated from environment. Bacteriophages were characterized to determine their role in the lysogenic conversion of bacteria and their possible usage in <em>B. bronchiseptica </em>control. For this purpose, morphological characteristics of the selected phages, the phage lytic spectrum, and the characteristics of phage genome and the proteins were examined. Also, the stability of phage in different environmental conditions was studied as well as their lytic efficiency, effect on the biofilm formation and formed biofilm. The paper also examined the role of phages in the production of biofilm, resistance to antibiotics, the process of hem olysis and the motility of<em> B. bronchiseptica </em>species. The results of this study clearly indicate the role of phage in lysogenic conversion in <em>B. bronchiseptica</em> as well as their potential for <em>B. bronchiseptica</em> control.</p>

<p>U ovom radu vr&scaron;ena je izolacija sojeva<em>&nbsp; P. shigelloides</em>&nbsp; iz uzoraka povr&scaron;inskih voda<br />Panonske nizije i formirana je kolekcija kultura, nakon čega je obavljena karakterizacija<br />faktora virulencije i antibiotske rezistencije&nbsp; izolovanih sojeva. Pored toga vr&scaron;ena je<br />izolacija bakteriofaga specifičnih za vrstu <em>P. shigelloides</em> iz uzoraka povr&scaron;inskih i otpadnih voda kao i njihova karakterizacija. Karakterizacija je podrazumevala sledeće testove: ispitivanje efikasnosti lize, litičkog spektra, uticaja različitih ekolo&scaron;kih faktora,<br />određivanje proteinskog profila i karakterizaciju genoma. Pored toga, vr&scaron;ena je detekcija<br />izolovanih bakteriofaga kori&scaron;ćenjem protočnog citometra. Rezultati ovog rada su potvrdili<br />prisustvo bakterije <em>P. shigelloides</em>&nbsp; i njenih specifičnih bakteriofaga u povr&scaron;inskim&nbsp; vodama Panonske nizije. Budući da su bakteriofagi specifični za vrstu&nbsp;<em> P. shigelloides&nbsp;</em> po prvi put izolovani, rezultati ovog rada mogu predstavljajati prvi&nbsp; korak u ispitivanjima vezanim za regulaciju brojnosti ove bakterije putem primene bakteriofaga.</p> / <p>We analyzed surface waters collected in Panonian plane, for the presence of bacterium&nbsp; <em>P. shigelloides</em>. The bacterial strains were preserved and characterized for virulence factors and antibiotic resistance. In addition, isolation of&nbsp; <em>P. shigelloides</em>&nbsp; specific bacteriophages was performed. Characterization of isolated phages included the following tests: examination of lytic efficacy, lytic spectrum, the influence of various ecological factors, the determination of the protein profile and the characterization of the genome. In addition, isolated bacteriophages were detected using a flow cytometer. The results of this paper demonstrate that the surface waters of Panonian plane contain bacterium&nbsp; <em>P. shigelloides&nbsp;</em> and its specific bacteriophages. Since&nbsp; <em>P. shigelloides</em>&nbsp; &ndash;&nbsp; specific bacteriophages are for the&nbsp;first time isolated, the results of this paper can represent the first step in the studies related to the regulation of the number of this bacterium by the application of bacteriophages.</p>

Abstract Species of Lactobacillus (L.) are important starter and probiotic lactic acid bacteria used in the dairy industry. Industrial fermentation processes are prone to phage infections, which can cause severe economic losses. The main objective of this thesis was to examine in more depth the genetic variation and evolution of L. delbrueckii and L. rhamnosus phages. Aspects of interactions and co-evolution of a phage and its host have also been included in this study. In this study, the complete genomic DNA sequences of four Lactobacillus phages were determined and analyzed in detail. Specific phage genes and genetic elements were identified and studied in more depth. The L. delbrueckii phage JCL1032 was found to be a temperate phage which is able to integrate into two distinct genes of L. delbrueckii, but with exceptionally low frequency. The isolated JCL1032-lysogenic bacteria expressed a complex phage resistance against several L. delbrueckii phages. The rarely reported coexistence of phage adsorption resistance and immunity could not be explained by lysogenic conversion. Instead, the spontaneously induced JCL1032 may have provided a selective advantage to adsorption resistant lysogens. The biological activity of two group I introns residing within the terminase large subunit and tape measure genes of the JCL1032 genome (49,433 bp) was demonstrated. The diversification of L. delbrueckii phages is mainly due to insertions, deletions and recombination, as was demonstrated by comparative analyses of the LL-Ku and c5 genomes of 31,080 bp and 31,841 bp, respectively. Interestingly, both phages have possible autonomous transcription units of genes within their genomes. It seemed that evolution of the 36,366-bp genome of the L. casei phage Lc-Nu has been fuelled by deletions as well. The lytic phage Lc-Nu has an imperfect lysogeny module and the phage is genetically closely related to L. casei prophages. This clearly demonstrated that Lc-Nu has a recent temperate origin. This study provides genetic tools, genes, and regulatory elements for biotechnological applications and for developing starter strains with enhanced phage resistance properties. / Tiivistelmä Hapatteina ja probiootteina käytetyt Lactobacillus-maitohappobakteerit (L. ) ovat merkittävässä asemassa meijeriteollisuudessa. Teolliset käymisprosessit ovat alttiita faagi-infektioille, jotka voivat aiheuttaa tuotantolaitoksille huomattavia taloudellisia tappioita. Tämän tutkimuksen päätavoitteena oli syventää tietoa L. delbrueckii ja L. rhamnosus -bakteereita infektoivien faagien geneettisestä muuntelusta ja evoluutiosta. Tutkimuksessa käsitellään myös faagin ja isäntäbakteerin välistä vuorovaikutusta sekä yhteisevoluutiota. Tutkimuksessa määritettiin neljän Lactobacillus-faagin genominen DNA-sekvenssi, identifioitiin faagigeenejä ja muita geneettisiä elementtejä sekä tutkittiin niiden toimintaa. L. delbrueckiin JCL1032-faagi osoittautui tutkimuksessa temperaatiksi. JCL1032-genomi voi integroitua kahteen eri geeniin isäntäbakteerin kromosomissa, joskin lysogeniafrekvenssi on hyvin alhainen. Tutkimuksessa eristetyt JCL1032-lysogeeniset bakteerikannat olivat resistenttejä useille Lactobacillus-faageille. Osassa lysogeenisia bakteereita resistenssi ilmeni jo faagin adsorptiovaiheessa. Vastaavanlainen ilmiö on kuvattu vain harvoin aiemmin. Havaittua kompleksista resistenssiä ei voitu selittää lysogeenisella konversiolla. Sen sijaan ilmiön taustalla voi olla JCL1032-profaagien spontaani indusoituminen bakteerin kromosomista, mikä voi antaa valintaetua adsorptioresistenteille lysogeenisille bakteereille. JCL1032-genomissa (49 433 emäsparia) osoitettiin olevan kaksi biologisesti aktiivista intronia terminaasin suurta alayksikköa ja hännän mittaproteiinia koodaavissa geeneissä. LL Ku- ja c5-faagien genomien (31 080 ja 31 841 emäsparia) vertailu osoitti L. delbrueckii -faagien evoluution olevan pääasiassa seurausta insertioista, deleetioista ja rekombinaatiosta. Kummassakin genomissa oli mahdollisesti päällekkäisiä ja itsenäisesti transkriptoituvia geenialueita. Deleetiot ovat muokanneet myös L. casein lyyttisen Lc- Nu-faagin genomia (36 466 emäsparia). Faagin lysogeniamoduuli sisälsi vain osan lysogeeniseen elinkiertoon tarvittavista geeneistä. Lc-Nu on geneettisesti läheistä sukua L. casei -profaageille, mikä myös viittaa siihen, että Lc-Nu on kehittynyt temperaatista faagista. Tutkimustuloksia faagien geeneistä ja säätelyelementeistä voidaan hyödyntää hapatebakteerien faagiresistenssiominaisuuksien kehittämisessä sekä erilaisissa bioteknologisissa sovelluksissa.