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Iako su močvare stoljećima promatrane kao bezvrijedna i nepotrebna područja u zadnjim se desetljećima taj stav postepeno promijenio. Danas su močvarni ekosustavi prepoznati kao vrlo vrijedna staništa zbog izuzetno visoke produktivnosti te zbog bogatstva vrsta od najsitnijih mikroorganizama pa sve do biljaka i životinja. Cilj rada bio je istražiti sezonsku dinamiku autohtone mikrobne zajednice i fekalnih bakterija u posebnim hidrografskim uvjetima voda slane močvare Palud i usporediti je sa morskom mikrobnom zajednicom u neposrednoj blizini močvare. Područje posebnog ornitološkog rezervata Palud – Palù od posebnog je značaja za sve organizme koje žive na tome području, a močvara koja se nalazi u samome središtu rezervata je specifičan ekosustav na području sjevernog Jadrana. Uzorkovanje se je izvodilo na 9 prethodno određenih postaja, na području posebnog ornitološkog rezervata Palud – Palù, a održalo se je 7 puta u periodu od kraja srpnja 2021., do svibnja 2022. Određena je sanitarna kakvoća vode te brojnost autohtone mikrobne zajednice u močvari, moru te u močvarnom kanalu koji povezuje močvaru s morem. Također je napravljena i statistička analiza podataka radi prikaza korelacije između sezonalnosti i mjerenih abiotičkih čimbenika, kao i grupacija postaja ovisno o poziciji uzorkovanja i ovisno o prisutnosti indikatorskih mikroorganizama ili autohtone mikrobne zajednice. Tijekom toplijih mjeseci (ljeto 2021. i proljeće 2022.) koncentracija indikatora fekalnog onečišćenja, ali i brojnost autohtone mikrobne zajednice je bila veća nego tijekom hladnijih mjeseci (jesen 2021. i zima 2022.). Dobiveni rezultati uspoređeni su s prosječnim podacima za sjeverni Jadran dostupnim u literaturi, kao i s dugoročnim prosjecima podataka za postaju RV001 na 1 NM zapadno od Rovinja. Rezultati su pokazali da hidrografski parametri u močvari imaju velike sezonske oscilacije, ali i da morske mijene imaju izuzetno važnu ulogu u funkcioniranju mikrobne zajednice i čitavog ekosustava. Although wetlands have been viewed as worthless and unnecessary areas for centuries, this attitude has gradually changed in recent decades. Today, wetland ecosystems are recognized as very valuable habitats due to their extremely high productivity and the richness of species, from the smallest microorganisms to plants and animals. The aim of this research is to investigate the seasonal dynamics of the indigenous microbial community and fecal bacteria in the special hydrographic conditions of the waters of the Palud salt marsh and compare it with the marine microbial community in the immediate vicinity of the marsh. The area of the special ornithological reserve Palud - Palù is of special importance for all organisms that live in that area, and the marsh located in the very center of the reserve is a specific ecosystem in the area of the northern Adriatic. Sampling was carried out at 9 previously determined stations, in the area of the special ornithological reserve Palud - Palù and took place 7 times in the period from the end of July 2021 to May 2022. The sanitary quality of the water and the abundance were determined autochthonous microbial communities in the marsh, the sea and in the marsh channel that connects the marsh with the sea. A statistical analysis of the data was also made to show the correlation between seasonality and measured abiotic factors, as well as the grouping of stations depending on the sampling position and depending on the presence of indicator microorganisms or autochthonous microbial communities. During the warmer months (summer 2021 and spring 2022), the concentration of fecal pollution indicators, as well as the abundance of the autochthonous microbial community, was expected to be higher than during the colder months (autumn 2021 and winter 2022). The obtained results were compared with average data for the northern Adriatic available in the literature, as well as with long-term data averages for station RV001 at 1 NM west of Rovinj. The results showed that hydrographic parameters in the marsh have large seasonal oscillations, but also that sea changes play an extremely important role in the functioning of the microbial community and the entire ecosystem.

Probiotici su živi mikroorganizmi, najčešće bakterije mliječne kiseline, koji imaju blagotvorno djelovanje na zdravlje domaćina. Cilj rada je identificirati probiotičke bakterije u domaćem rasolu te usporediti brojnost probiotičkih bakterija između komercijalno dostupnih probiotika, domaćeg rasola te kupovnih i domaćih mliječnih proizvoda. U radu je korišteno 9 različitih uzoraka domaćeg rasola, 4 različita kupovna probiotika, 4 kupovna mliječna proizvoda te 4 domaća. Pripremljena su decimalna razrijeđenja svih uzoraka te su nacijepljena na MRS hranjivu podlogu. Izolirane probiotičke bakterije domaćeg rasola fenotipski su karakterizirane metodom bojanja po Gramu te su identificirane tehnologijom MALDI-TOF, a utvrđeno je da su prisutne bakterijske vrste Levilactobacillus brevis i Levilactobacillus buchneri (gram-pozitivne bakterije štapićastog oblika) te Pediococcus parvulus (gram-pozitivna bakterija okruglog oblika). Ovim je radom utvrđeno da broj bakterija u uzorcima domaćeg rasola iznosi 8,17±5,03 × 107 CFU mL-1, uzorci kupovnih mliječnih proizvoda sadrže 4,11±1,62 × 107 CFU mL- , domaći mliječni proizvodi sadrže 3,20±1,91 × 107 CFU mL-1, a komercijalno dostupni probiotici sadrže 4,88±0,54 × 1010 CFU g -1. Predlaže se daljnje istraživanje s više uzoraka domaćih namirnica kako bi se detaljnije usporedile prisutne bakterijske vrste te njihove brojnosti. Probiotics are living microorganisms. They are most often lactic acid bacteria which have a beneficial effect on the host's health. This work aims to identify probiotic bacteria in homemade cabbage brine and compare the number of probiotic bacteria between commercially available probiotics, homemade brine, and store-bought and domestic dairy products. Various samples were used in the study: 9 of homemade cabbage brine, 4 of commercially available probiotics, 4 of store-bought dairy products, and 4 of homemade dairy products. Decimal dilutions of all samples were prepared and inoculated onto MRS nutrient medium. The isolated probiotic bacteria of homemade cabbage brine were phenotypically characterized by the Gram staining method. The bacteria were then identified by MALDI-TOF technology. Bacterial species observed are Levilactobacillus brevis and Levilactobacillus buchneri (grampositive rod-shaped bacteria) and Pediococcus parvulus (round-shaped gram-positive bacteria). This work determined that the number of bacteria in samples of homemade cabbage brine is 8.17±5.03×107 CFU mL-1 . Commercially available dairy products contain 4.11±1.62×107 CFU mL-1, while domestic dairy products showed 3.20±1.91 ×107 CFU mL-1. Commercially available probiotics have 4.88±0.54×1010 CFU g-1. It is suggested further research with more samples of homemade foods for a more detailed comparison of the bacterial species present and their quantity.

Hidroksiapatit je obećavajući biomaterijal u regeneraciji kostiju zbog svojih bioaktivnih svojstva te strukturne i kemijske sličnosti s anorganskom fazom koštanog tkiva. Zbog nedostatka antibakterijskih svojstva, supstituira se ionom srebra za postizanje antibakterijske aktivnosti. Srebro posjeduje antibakterijska svojstva, no može biti citotoksično u većim koncentracijama. Za smanjenje citotoksičnosti srebrova iona, kosupstituira se stroncijevim ionom. Cilj ovog istraživanja bio je odrediti antibakterijsku aktivnost uzoraka hidroksiapatita obogaćenog ionima srebra i hidroksiapatita obogaćenog ionima srebra i stroncija metodom disk difuzije i određivanjem brojnosti bakterija u suspenziji. Testirane bakterije bile su Escherichia coli i Staphylococcus aureus kao predstavnici najčešćih patogena u infekcijama kostiju. Nesupstituirani hidroksiapatit nije pokazao antibakterijsku aktivnost. Svi uzorci hidroksiapatita supstituirani srebrovim ionom i uzorci hidroksiapatita supstituirani srebrovim i stroncijevim ionom pokazali su antibakterijsku aktivnost u obje metode što je vidljivo iz pojave zone inhibicije i analizom broja živih bakterija u bakterijskoj suspenziji nakon kontakta s uzorcima u određenom vremenu. Antibakterijska aktivnost uzoraka hidroksiapatita supstituiranih ionima srebra bila je ovisna o vremenu kontakta i količini supstituiranog srebrova iona. Hydroxyapatite is a promising biomaterial in bone regeneration due to its bioactive properties as well as its structural and chemical similarities to the inorganic phase of bone tissue. Due to lack of antibacterial properties, it is substituted with a silver ion to achieve antibacterial activity. Silver has antibacterial properties, but can be cytotoxic in higher concentrations. To reduce the cytotoxicity of silver ions, it is co-substituted with strontium ion. The aim of this study was to determine the antibacterial activity of samples of hydroxyapatite enriched with silver ions and hydroxyapatite enriched with silver and strontium ions using the disk diffusion method and determining the number of bacteria in suspension. The tested bacteria were Escherichia coli and Staphylococcus aureus as representatives of the most common pathogens in bone infections. Unsubstituted hydroxyapatite did not show antibacterial activity. All hydroxyapatite samples substituted with silver ion and hydroxyapatite samples substituted with silver and strontium ions showed antibacterial activity in both methods, which is evident from the appearance of the inhibition zone and the analysis of the number of living bacteria in the bacterial suspension after contact with the samples for a certain amount of time. The antibacterial activity of hydroxyapatite samples substituted with silver ions was dependent on the contact time and the amount of substituted silver ions.

Beta-hemolitički streptokoki (BHS) su skupina bakterija koja na krvnom agaru vrši potpunu hemolizu eritrocita te uzrokuju mnoge bolesti poput gnojne upale grle, šarlaha, impetiga ili apscesa mozga. Prema Lancefield klasifikaciji, tu spada grupa A koju predstavlja Streptococcus pyogenes, Streptococcus agalactiae iz grupe B, Streptococcus dysgalactiae ssp. equsimilis iz skupina C i G te skupina Streptococcus anginosus s nekoliko vrsta skupine F, A, C i G te oni netipabilni. Sve se vrste mogu pronaći u ždrijelu čovjeka, osim S. agalactiae. Asimptomatski nositelj (kliconoša) je osoba kod koje ne dolazi do vidljive pojave simptoma bolesti, ali može prenijeti uzročnika te bolesti na drugu osobu. Kod kliconoše postoji infekcija, ali ona je subkliničke slike, odnosno neprimjetna je. Kliconoštvo za BHS može se naći u nazofarinksu, orofarinksu ili perinealnoj regiji. Cilj ovog istraživanja bio je ispitati stavove i znanje studenata o problematici BHS te provjeriti može li edukacija i uzimanje briseva imati pozitivan učinak na isto. Napravljena je i epidemiološka slika ispitanika gdje je udio asimptomatskih nositelja beta-hemolitičkih streptokoka iznosio 11,58 %. Nadalje, rezultati su potvrdili da čak i kratka edukacija te uzimanje briseva imaju statistički značajan pozitivan učinak na poznavanje problematike beta-hemolitičkih streptokoka i kliconoštva. Nakon edukacije, uočena je i promjena stajališta ispitanika prema ovoj važnoj problematici javnog zdravstva. Beta-hemolytic streptococci (BHS) are a group of bacteria that show complete hemolysis of erythrocytes on blood agar and cause many diseases such as pharyngitis, scarlet fever, impetigo and brain abscess. According to the Lancefield classification, this includes group A represented by Streptococcus pyogenes, Streptococcus agalactiae from group B, Streptococcus dysgalactiae ssp. equsimilis from groups C and G and group Streptococcus anginosus with several species of groups F, A, C and G and those incompatible. All species can be found in the human pharynx except S. agalactiae. An asymptomatic carrier is a person who does not show symptoms of the disease but can transmit the cause of the disease to another person. The carrier has an infection, but it is subclinical, i.e., it is imperceptible. BHS can be found in the nasopharynx, oropharynx, or perineal region. The aim of this research was to examine the attitudes and knowledge of students about BHS and to check whether education and swabs can have a positive effect on it. An epidemiological study of the subjects was also made, where the share of asymptomatic carriers of beta-hemolytic streptococci was 11.58%. Furthermore, the results confirmed that even a short education and swabbing have a statistically significant positive effect on knowledge of beta-hemolytic streptococci and asymptomatic carriers. After the education, a change of attitude towards this important issue of public health was noticed.

Rod Vibrio sadrži važne patogene školjkaša i drugih beskralješnjaka, riba i ljudi. Kako bi se očuvalo njihovo zdravlje bitna je njihova identifikacija do razine vrste. Cilj ovog istraživanja je bio identificirati odabrane Vibrio uzorke do razine vrste, odrediti filogenetske odnose i utvrditi sličnosti, tj. razlike u strukturi zajednica Vibrio bakterija između akvakulture školjkaša Limskog kanala i Malostonskog zaljeva. Analizirani su uzorci morske vode, sedimenta kao i tkiva školjkaša mediteranske dagnje (Mytilus galloprovincialis) i europske plosnate kamenice (Ostrea edulis). Metodom lančane reakcije polimerazom (PCR) ciljane su različite kodirajuće regije šest konstitutivno eksprimiranih gena (engl. housekeeping genes) i 16S rRNA. Uzorci su poslani na sekvenciranje nakon čega je provedena metoda multilokusnog sravnjivanja sljedova (MLSA). Za filogenetsku analizu korištene su metode najveće vjerojatnosti i susjednog sparivanja. Eksperimentalni uzorci unutar Harveyi podskupine su se razlučili do razine vrste, a unutar Splendidus podskupine do razine grupacije. Na području uzgajališta školjkaša Limski kanal identificirano je šest vrsta te pet Splendidus grupacija, dok je na području uzgajališta školjkaša Malostonski zaljev identificirano pet vrsta i šest Splendidus grupacija. Dokazana je prisutnost više patogenih i uvjetno patogenih Vibrio vrsta za na području istočnog Jadrana. The genus Vibrio consists of important shellfish and other invertebrate, fish and human pathogens. In order to preserve their health, identification to species level is essential. The aim of this study was to identify selected Vibrio samples to species level, to determine phylogenetic relationships and to determine similarities and differences in the structure of the Vibrio community between the shellfish aquaculture of the Lim Bay and Mali Ston Bay. Samples of seawater, sediments, tissues of Mediterranean mussel (Mytilus galloprovincialis) and European flat oyster (Ostrea edulis) were analyzed. Different coding regions of six housekeeping genes and 16S rRNA were targeted by the polymerase chain reaction (PCR). Samples were sent for sequencing after which a multilocus sequence alignment (MLSA) was performed. For phylogenetic analysis two methods were used: Maximum likelihood and Neighbour-joining. Experimental samples within the Harvey clade were identified to the species level while experimental samples within the Splendidus clade to the grouping level. In Lim Bay, six species and five Splendidus groups have been identified, while five species and six Splendidus groups in Mali Ston Bay. The presence of several pathogenic and conditionally pathogenic Vibrio species in the eastern Adriatic has been proven.

Bioplin nastaje procesom anaerobne pretvorbe organskih materijala uz prisustvo anaerobnih organizama. Jedno od biotehnoloških rješenja za proizvodnju bioplina su reaktori s aktivnim muljem koji koriste poljoprivrednu energetsku kulturu Miscanthus x giganteus kao alternativnu sirovinu kukuruznoj silaži. Cilj rada je bioaugmentirati reaktore za proizvodnju bioplina s ciljem povećanja njihove učinkovitosti. Bakterije koje smo uspjeli izolirati iz aktivnog mulja koristile su M. giganteus kao jedini izvor ugljika. Nakon izolacije bakterije uspješno su se imobilizirale na perlit biofilmom te tako su tvorile biočestice. Postavljanjem 9 različitih bioreaktora i njihovim praćenjem proizvodnje bioplina ukazalo se da nema značajnih razlika u proizvodnji bioplina između reaktora s biočesticama, bakterijskom suspenzijom i aktivnog mulja s dodatkom M. giganteus. Predlaže se daljnje i opširnije istraživanje s više replika te s različitim koncentracijama biočestica, da bi se vidjelo može li se povećati prinos bioplina u nekoj drugoj konfiguraciji, ili možda da se poveća stabilnost različitih bioreaktora. Biogas is produced during the process of anaerobic conversion of organic materials in the presence of anaerobic organisms. A biotechnological solution for biogas production is active sludge reactor using the agricultural energy crop Miscanthus x giganteus as an alternative raw material to corn silage. The aim of this paper is to bioaugment production reactors biogas in order to increase their efficiency. Successfully isolating the bacteria from activated sludge required using M. giganteus as the only carbon source. After isolating the bacteria, they were successfully immobilized on perlite using biofilm and subsequently formed bioparticles. Setting 9 different bioreactors and monitoring biogas production indicated that there are no significant differences in biogas production between bioparticle reactors, bacterial suspension and activated sludge with added M. giganteus. The recommendation is to undertake further and more extensive research with more replications and different concentrations of bioparticles, in order to ascertain whether biogas can be increased in another configuration, or perhaps increase the stability of different types of bioreactors.

Posljednjih nekoliko godina demonstrirane su opasnosti koje virusne bolesti predstavljaju za javno zdravstvo. Kada bi se virusna epidemija dogodila u svemirskoj bazi, posljedice bi bile mnogo gore nego na Zemlji. U ovom istraživanju, virioni kolifaga MS2, surogata za enteričke i respiratorne viruse, izloženi su nekim fizikalnim uvjetima dubokog svemira – temperaturama -80 °C i do 80 °C, simulantu mjesečeve prašine, tlaku bliskom vakuumu, visokom intenzitetu rendgenskih zraka i disperziji u hladnim kapljicama u prisutnosti UV-a. Rezultati pokazuju da većina testiranih uvjeta dubokog svemira značajno inaktivira viruse. Na neke od uvjeta, virusi su doduše bili otporniji nego što je očekivano npr. ekstremno niske temperature, nizak tlak i rendgenske zrake. Također, simulant mjesečeve prašine dao je određenu razinu zaštite virusima na termičku inaktivaciju, ali pri niskim temperaturama, djelovala je negativno na viruse. Uz to, pokazano je da se MS2 može širiti preko kapljica suspendiranih u zraku, čak i uz prisutnost UV-a što doprinosi ideji o stabilnosti virusa u kapljicama vode koje nastaju u izbojima vode na ledenim mjesecima sunčevog sustava poput Europe ili Enceladusa. Ovo istraživanje pokazuje da da fizikalni uvjeti dubokog svemira mogu značajno inaktivirati visoko rezistentni virus MS2 i postavlja temelje za buduća istraživanja u području svemirske virologije. Recent years have demonstrated the dangers that viral diseases pose to public health. If an outbreak happens in a space habitat, the consequences would be more devastating than on Earth. In this research, virions of coliphage MS2, a surrogate for enteric and respiratory viruses have been exposed to some of the physical conditions of deep space – temperatures of -80 °C, and up to 80 °C, lunar dust simulant, near-vacuum pressure, high X-ray doses, and dispersion in cold droplets under presence of UV. Results show that most tested conditions of space rapidly inactivate viruses. However, to some of those conditions like extremely low temperatures, near-vacuum, or X-rays, viruses showed a higher degree of resistance than expected. Also, lunar dust simulant showed some degree of protection for viruses at high temperatures but aids their inactivation at low temperatures. Additionally, MS2 has been shown to be transmissible in air droplets and aerosols, even under UV light, aiding the idea of viral stability in water plumes of solar system’s icy moons like Europa or Enceladus. Taken together, this study shows that physical conditions of deep space inactivate highly environmentally resistant MS2 virus to a great extent and paves the way for future research in space virology.

Ovaj završni rad je kratak pregled dosadašnjeg znanja o crijevnom mikrobiomu i njegovom utjecaju na ljudsko zdravlje. Ukratko se predstavlja znanje o interakcijama organizama unutar crijeva te s domaćinom, kao i utjecaj različitih faktora na mikrobiom. Opisane su neke bolesti, njihova povezanost s mikrobiomom i terapije koje bi potencijalno mogle prijeći u široku uporabu. Poseban osvrt pridaje se arhejama koje su važan sastavni dio crijevnog mikrobioma. Predstavljena je građa arhejskog staničnog ovoja, raznolikost arheja te njihov utjecaj na ljudsko zdravlje. U konačnici, može se zaključiti da je istraživanje crijevnog mikrobioma čovjeka obećavajuće područje zbog razvoja terapija koje se temelje na crijevnom mikrobiomu, a mogle bi se korisiti za liječenje kako crijevnih, tako i drugih bolesti te općenito za jačanje imunološkog sustava. Potrebna su daljnja istraživanja prijenosa komenzalnih mikroorganizama, interkacije među mikroorganizmima te s domadarima i sami sastav mikrobioma, osobito arheje koje su često zanemarene zbog metodoloških problema. This final paper is a short review of current knowledge about the intestinal microbiome and its impact on human health. The knowledge of interactions between organisms inside the intestine and with the host is briefly represented, as well as the impact of various factors on the microbiome. Some diseases, their connection to the microbiota and therapies that could become widely used have been described. Special attention is given to the Archaea, which are an important part of the intestinal microbiota. Archaeal cell envelope structure, their diversity and their impact on human health are presented. Finally, it can be concluded that research of the human microbiota is a promising field because of the development of therapies that are based on the intestinal microbiota and that could be used to treat intestinal illnesses, as well as other diseases and generally to strenghten the immune system. Further research of the transmission of commensal microorganisms, interactions between them and with hosts, and the composition of the microbiota itself is needed, especially with Archaea which are often neglected because of methodological problems.

Vuna u odnosu na druge prirodne materijale ima sposobnost reducirati razvoj neugodnih mirisa na odjeći. Smatra se da struktura vlakna vune ne pogoduje razvoju bakteriju, a lanolin na površini vlakna štiti ovcu od infekcija. Cilj ovog istraživanja bio je procijeniti uz pomoć testa difuzije u agaru (ISO 20645:2004) antibakterijska svojstva vune te predložiti mehanizam djelovanja određivanjem broja vezanih bakterija na vuni nakon 1 i 24-satnog kontakta s bakterijama na hranjivim podlogama. Vuna je uspoređena s pamukom i medicinskom gazom. Testirane bakterije bile su Staphylococcus aureus, Klebsiella pneumoniae, Bacillus cereus, te više sojeva bakterije Acinetobacter baumanni, uključujući dva bolnička izolata. Prema testu difuzije na agaru, vuna je pokazala dobar antibakterijski učinak (određen odsustvom bakterija na hranjivoj podlozi ispod tekstilnog uzorka) za sve bakterije osim S. aureus. Pamuk je za testirane bakterije pokazao od nedovoljnog do dobrog antibakterijskog učinka. Medicinska gaza je pokazala granični i nedovoljan učinak za sve testirane bakterije. Za većinu testiranih bakterija ne postoji značajna razlika u broju vezanih bakterija između vune, pamuka i gaze nakon 1-satnog kontakta. Nakon 24-satnog kontakta za većinu bakterija vuna je pokazala manji ili jednak broj vezanih bakterija u odnosu na gazu, a veći ili jednak u odnosu na pamuk. Površina vune omogućava jako dobro prianjanje bakterija, ali se bakterije nastavljaju na njoj značajno umnožavati. Antibakterijski učinak je stoga rezultat čvrstog vezanja bakterija na vlakna vune, čime se smanjuje prisutnost bakterija na hranjivoj podlozi ispod vunenog uzorka. Wool, compared to other natural materials, has the ability to reduce the development of unpleasant odors on clothing. It is believed that the structure of wool fibers does not favor the development of bacteria, and lanolin on the surface of the fiber protects the sheep from infections. The aim of this study was to evaluate the antibacterial properties of wool using agar diffusion test (ISO 20645: 2004) and to suggest a mechanism of action by determining the number of bound bacteria on wool after 1 and 24 hours of contact with bacteria on nutrient media. Wool was compared to cotton and medical gauze. Tested bacteria were S. aureus, K. pneumoniae, B. cereus, and several strains of A. baumanni, including two hospital isolates. According to the agar diffusion test, wool showed a good antibacterial effect (determined by the absence of bacteria on the nutrient medium below the textile sample) for all bacteria except S. aureus. Cotton showed insufficient to good antibacterial effect for tested bacteria. Medical gauze showed marginal and insufficient effect for all tested bacteria. For most of the bacteria tested, there is no significant difference in the number of bound bacteria between wool, cotton and gauze after 1 hour of contact. After 24 hours of contact for most bacteria, wool showed less or equal number of bound bacteria compared to gauze, and greater or equal to relative to cotton. The surface of the wool allows very good adhesion of bacteria, but bacteria continue to multiply significantly on it. The antibacterial effect is therefore the result of a strong binding of bacteria to the wool fiber, thus reducing the presence of bacteria on the nutrient media under the wool sample.

Surfaktanti su skupina kemijskih spojeva koji su zbog svojeg amfipatskog karaktera naišli na široku upotrebu u industriji, domaćinstvu, kozmetici, farmaceutskoj industriji, medicini te biološkim istraživačkim laboratorijima diljem svijeta. Zbog toliko široke upotrebe, određeni dio korištenih surfaktanta neizbježno završava u okolišu ispuštanjem u otpadne ili površinske vode iz kojih se dalje procjeđuju u sediment i dublje slojeve tla, ali i sam proces sinteze nepovoljno utječe na onečišćenje okoliša. U većini slučajeva koncentracije surfaktanata ispuštenih u okoliš ne premašuju legalno propisane koncentracije, međutim do negativnih utjecaja na floru i faunu u izloženih područjima može doći i pri niskim koncentracijama. Najproblematičniji su QAC koji su pokazali najveću toksičnost za vodene organizme, međutim danas nastaje sve više alternativnih rješenja poput gemini QAC, kao i zelenih surfaktanata koji posjeduju istu, ako ne i veću moć smanjenja površinske napetosti, ali su ekološki prihvatljivi kako u procesu sinteze, tako i u procesu (bio)razgradnje. Napretkom razvoja znanosti zasigurno će doći i do novih otkrića glede otkrića mehanizma djelovanja, ali i sinteze i razgradnje novih, ekološki prihvatljivijih surfaktanata. Surfactants are widely used chemical compounds regarding its amphiphilic character. They are used in industry, household, cosmetic and pharmaceutical industry, medicine as well as in many biology research laboratories all around the world. Because of them being ubiquitous, a great deal of them inevitably ends up in environment. Surfactants are being released via wastewaters as well as being directly released in surface waters from which they percolate in sediment and soil. The surfactant synthesis process affects environmental pollution as well. In most cases environment released surfactant concentrations aren't above the toxicity level, however, even low concentrations are able to harm flora and fauna in the „exposed“ area. The most troubling are QACs. They have shown the highest toxicity rate on aquatic organisms. On the other hand, as each day passes by many new surfactants as gemini and green surfactants, are being invented. Their cleaning power is as good, if not better, as the standard surfactants cleaning power and they are biofriendly regarding both the synthesis and (bio)degradation process. As science moves forward there will surely emerge new revelations related to the mechanisms, synthesis and degradation of new, environmental friendly surfactants.

Važnost akvakulture u proizvodnji hrane sve je veća, a među vrstama ribe koje se najviše uzgajaju u Jadranskom moru je lubin (Dicentrarchus labrax). Za liječenje oboljelih riba u uzgajalištima koriste se antibiotici koji doprinose otpornosti bakterija iz okoliša na antibiotike. Cilj rada bio je usporediti sastav mikrobnih zajednica u uzgajalištima sa i bez primjene antibiotika. Istaknuta je mikrobna zajednica kože lubina zbog važnosti za obranu organizma od patogena. Uzorkovanje je provedeno tijekom ljeta na uzgajalištima kod otoka Cresa i otoka Vrgade. Obavljena je fizikalno-kemijska analiza morske vode te mikrobiološka analiza kože, morske vode i sedimenta. Ispitana je otpornost bakterija na antibiotike i provedena je izolacija bakterijske DNA. Bakterije su identificirane određivanjem slijedova nukleotida gena 16S rRNA umnoženih u lančanoj reakciji polimerazom (PCR). U uzorcima morske vode, sedimenta i brisevima kože identificirano je 55 bakterijskih vrsta, većinom specifičnih za svaki tip uzorka. Uspoređujući uzgajališta, jedini zajednički rodovi u brisevima kože bili su Pseudomonas i Vibrio, dok za otpornost bakterijskih izolata s kože nije utvrđena statistički značajna razlika (p < 0,05). Vibrio alginolyticus, V. anguillarum i V. harveyi patogene su bakterije identificirane u brisevima kože s utvrđenom otpornošću na određene antibiotike. Rezultati ukazuju na potencijalan problem u uzgajalištima u slučaju pojave bolesti. The importance of aquaculture is continually increasing in the food-producing sector, and one of the most farmed fish in Adriatic Sea is European seabass (Dicentrarchus labrax). Antibiotics are used for treatment of diseased fish in aquaculture, thus contributing to the spread of antibiotic resistance among environmental bacteria. The aim of this paper is to compare microbial communities between two fish farms, one which uses antibiotics for treatment and the other one which holds antibiotic-free certificate. Skin microbiome is highlighted due to the role of skin in defense against pathogens. Samples were collected during summer from two fish farms, near island Cres and near island Vrgada. Physico-chemical analysis of seawater was performed, as well as microbiological analysis of skin swabs, seawater and sediment. The antibiotic susceptibility test and bacterial DNA extraction were also performed. Bacteria identification was performed with determining the nucleic acid sequence of 16S rRNA gene amplified in polymerase chain reaction (PCR). There were 55 bacteria species identified in skin swabs, seawater and sediment samples. Species were mostly specific to each sample type. Only two bacterial genera, Pseudomonas and Vibrio, were identified in skin swabs samples from both fish farms. There was no statistically significant difference (p < 0,05) in antibiotic resistance of bacterial isolates from skin swabs between two fish farms. Pathogenic bacteria identified in skin swabs were Vibrio alginolyticus, V. anguillarum and V. harveyi, and showed resistance to certain antibiotics. The results indicate a potential problem for fish health management in case of disease outbreak.

Biofilm se najčešće opisuje kao zajednica mikroorganizama pričvršćenih na podlogu i uklopljenih u matriks izvanstanične polimerne tvari (engl. extracellular polymeric su bstance, EPS ). Pokretljivost je ključna za razne oblike bakterijskog ponašanja kao što je virulencija, kolonizacija novih staništa pa tako i stvaranje biofilma. S obzirom da se infekcije uzrokovane biofilmom puno teže liječe zbog veće rezistenc ije na antim ikrobnu terapiju, istraživanja na području biofilma i bakterijske pokretljivosti mogu dati vrlo korisne informacije za formiranje strategija kontrole bakterijskih infekcija. Za istraživanje su korištene bakterije Acinetobacter baumannii i Bacil lus cereus . Cilj istraživanja bio je pobliže istražiti oblik bakterijske pokretljivosti, pri kojoj bakterijske stanice migriraju iz biofilma formiranog na sučelju zraka i tekućine vertikalno gore po čvrstoj, inertnoj staklenoj površini koja nije bila u dot icaju s hran jivim medijem. Za vizualizaciju bakterija, preparati su se bojili Alcian blue metodom. Zaključeno je da viša koncentracija bakterija pogoduje bržem i snažnijem formiranju biofilma te da biofilm prethodi i posreduje u napredovanju bakterija. Tak ođer, zaklju čeno je da napredovanje bakterija putem biofilma omogućuju kapilarne sile i aktivni oblici bakterijske pokretljivosti. Biofilm is most commonly described as a consortium of microorganisms attached to a solid surface and incorporated into an extracellular polymeric substance. Mobility is crucial for various forms of bacter ial behavior such as v irulence, colonization of new habitats and thus biofilm formation. Given that biofilm infections are much more difficult to treat because of their high er resistance to antimicrobial therapy, research on biofilm and bacterial motility can provide very usef ul information for developing bacterial infection control strategies. In this research, bacteria Acinetobacter baumannii and Bacillus cereus were used. The goal of the study was to investigate more closely the form of bacterial motili ty, in which bacterial cells migrate from the biofilm formed at the air liquid interface vertically upwards over a solid, inert glass surface that was not covered with nutrie nt medium. For the visualization of bacteria, the preparations were stained using alcian blue metho d. It was concluded that higher bacterial concentration favors faster and stronger biofilm formation and that biofilm precedes and mediates bacterial progres s. Also, it was concluded that bacterial mobility was facilitated by capillar y for ces and active fo rms of bacterial motility.

Cilj ovog rada je bio istražiti i usporediti kako fosfat-akumulirajuća bakterija Acinetobacter junii preživljava nepovoljne vrijednosti pH u planktonskoj formi (slobodne stanice) i imobilizirana na mineralni nosač, u ovom slučaju prirodni zeolitni tuf, (biočestice), te kako to utječe na njenu sposobnost uklanjanja fosfata iz sintetske otpadne vode. Imobilizirane bakterije su bile otpornije na nepovoljne vrijednosti pH od planktonskih, a njihova stopa umnožavanja je bila značajno veća. Metaboličku aktivnost su zadržale i planktonske i imobilizirane bakterije, no postotak uklonjenog fosfata je bio veći u slučaju biočestica. Rezultati pokazuju da je prirodni zeolitni tuf obečavajući nosač fosfat-akumulirajućih bakterija u svrhu korištenja u postrojenjima za pročišćavanje otpadnih voda. The aim of this study was to determine and compare how phosphate-accumulating bacterium Acinetobacter junii survives unfavorable pH levels in planktonic form (free cells) and immobilised on a mineral carrier, in this case natural zeolitic tuff, (biosolids), and also how this affects the ability to remove phosphate from synthetic wastewater. Immobilised bacteria were better at withstanding unfavorable pH levels than planktonic, and their reproduction rates were signifcantly higher. Both planktonic and immobilised bacteria remaind metabolically active, but percentage of removed phosphate was higher for biosolids. Results show that natural zeolitic tuff is a promising carrier for phosphate accumulating bacteria to be used in wastewater treatment plants.

Posljednjih godina brojni su dokazi ukazivali na središnju ulogu komenzalnih bakterija koje koloniziraju tjelesne površine kao ključne odrednice zdravih ili patoloških stanja. Svaki je pojedinac naslijedio specifičnu mikrobiotu crijeva od svog rođenja, a njegova se crijevna mikrobiota razvija i mijenja sa starenjem, prehranom i izlaganjem heterogenom okolišu. Sve je veća pažnja posvećena prema karakterizaciji sastava i funkcionalnosti mikrobiote probavnog sustava, te njenog utjecaja na homeostazu domaćina. Danas su istraživanja usmjerena i na proučavanje HPA veze, koja je odgovorna na reagiranje tijela u stresnim uvjetima, i crijevne mikroflore te je dokazano da mikrobiota ima veliku ulogu u regulaciji normalnog ponašanja domaćina ali i ulogu u regulaciji kemije u mozgu koja je bitna kod raspoloženja i nekih neuropsihijatrijskih bolesti. Također, mikrobiota u crijevima obavlja brojne vitalne funkcije uključujući proizvodnju vitamina, metabolizam prehrambenih spojeva, zaštitu od širenja i sistemske infiltracije crijevnih patogena. Mikrobna ravnoteža u crijevima ima ključnu ulogu u pravilnom izvršavanju svih ovih ključnih metaboličkih funkcija. Svaka neravnoteža u ovoj osjetljivoj ravnoteži kao i u BGM osi može dovesti do oštećenja mikrobiote, stanja zvanog disbioza, koje je povezano s nekoliko ljudskih patologija, poput depresije, anksioznosti, autizma, alzheimera i parkinsonove bolesti. S druge strane, mnogi probiotici mogu zaštititi domaćina, ponovno uspostavljajući uvjete zdrave crijevne mikrobiote kod bolesnika s disbiozom uključujući bolesnike koji pate od nekih neuropsihijatrijskih poremećaja. U budućnosti, dizajn novih psihobiotika može zahtijevati personalizirani integrirani pristup uzimajući u obzir sprcifičnu kliničku i patološku pozadinu svakog pojedinog pacijenta koji se liječi, kako bi se postigli samo pozitivni ishodi primjene probiotika i/ili fekalne transplantacije po mogućnosti bez štetnih nuspojava. In recent years, numerous evidence has shown the central role of commensal bacteria that colonize body surfaces, as key determinant of healthy or pathological conditions. Each person has inherited a specific intestinal microbiota, which evolves and changes with aging, diet and exposure to heterogeneous environment. Increased attention has been paid to the composition characterization and functionality of gut microbiota and its impact on host homeostasis. Today, researches are focused on the study of the HPA axis also, which is responsible for body’s response to stressful situations, and on the study of the intestinal microflora. It has been proved that the gut microbiota has an important role in the regulation of normal host behavior, but also in the regulation of brain chemistry, which is important for mood and some neuropsychiatric diseases. Moreover, the intestinal microbiota performs many vital functions, including the production of vitamins, metabolism of nutritional compounds, protection against spreading and systemic infiltration of intestinal pathogens. Microbial balance in the intestine has a key role in the proper performance of all these key metabolic functions. Any imbalance in this delicate balance, as well as in the BGM axis, can lead to damage of microbiota, a condition called dysbiosis, which is associated with several human pathologies, such as depression, anxiety, autism, Alzheimer's and Parkinson's disease. On the other hand, many probiotics can protect the host, reestablishing healthy conditions in the intestinal microbiota of patients with dysbiosis, including patients who suffer from some neuropsychiatric disorders. In the future, the design of new psychobiotics may require a personalized integrated approach, taking into account the specific clinical and pathological background of each treated patient, in order to achieve only positive outcomes of probiotic application and/or fecal transplantation, preferably without adverse side effects

Bakterija Acinetobacter baumannii je Gram-negativni kokobacil prirodno prisutan u vodi i tlu. Prošlih nekoliko desetljeća glavni je uzrok bolničkih infekcija. Zbog sposobnosti brzog stjecanja gena za otpornost na antibiotike, pronalazak prikladnog tretmana postaje sve problematičniji. Glavni mehanizmi rezistencije kod Gram-negativnih bakterija uključuju enzimatsku inhibiciju, modifikaciju mete djelovanja antibiotika, prekomjerna ekspresija efluks sustava i mutacije porina. Navedene strategije koristi i bakterija A. baumannii. Ova bakterija sadrži intrinzične i stečene enzime β-laktamaze, koje inhibiraju djelovanje β-laktama hidrolizom, i aminoglikozid-modificirajuće enzime, koji modificiraju molekule aminoglikozida prijenosom funkcionalne skupine. Primjer enzima koji modificira metu djelovanja aminoglikozida su 16S rRNA metilaze. Nadalje, mutacije u specifičnim genima uzrokuju promjenu naboja površine stanice bakterije, što odbija određene antibiotike i onemogućuje im interakciju s vanjskom membranom. Prisutnost insercijskih sekvenci ili mutacija u promotoru i operatoru često uzrokuje prekomjernu ekspresiju intrinzičnih efluks sustava, koji tada doprinose rezistenciji na velik broj antibiotika. Mutacije koje uzrokuju gubitak funkcije porina doprinose stupnju antibiotske rezistencije na način da se smanjuje propusnost vanjske membrane. Genetičke strukture poput insercijskih sekvenci, integrona, transpozona i otoka rezistencije široko su rasprostranjene u genomu A. baumannii. Ovi mobilni genetički elementi omogućuju A. baumannii stjecanje i akumuliranje, te rasprostiranje čimbenika rezistencije putem horizontalnog genskog prijenosa. Acinetobacter baumannii is a Gram-negative coccobacillus commonly found in soil and water. It has been a major cause of nosocomial infections for the past few decades and is becoming more and more difficult to treat due to its ability to rapidly acquire resistance determinants to different types of antibiotics. Main resistance mechanisms performed by Gram-negative bacteria include enzymatic inhibition, modifications of target molecules, overexpression of efflux systems and porin mutations. A. baumannii has intrinsic and acquired enzymes β-lactamases, that inhibit β-lactam action by hydrolysis, and aminoglycoside-modifying enzymes, that modify the aminoglycoside molecule by transfer of functional groups, represent enzymatic inhibition resistance strategy. Enzymes like 16S rRNA methylase has emerged in A. baumannii as aminoglycoside target modifying enzyme. Furthermore, mutations in specific genes result in modification of cell surface local charge, which repels certain antibiotics from interacting with the outer membrane. Intrinsically present efflux systems are contributing to resistance to wide range of antibiotics, when overexpressed due to the presence of IS elements or the mutation in promoter or operator sequences. Porin knockout mutations contribute to antimicrobial resistance in a way that it leads to reduced membrane permeability. Genetic structures such as insertion sequences, transposons, integrons and resistance islands are widely distributed throughout the genome of A. baumannii. Due to these mobile genetic elements, A. baumannii has a remarkable ability to acquire and accumulate, as well as disseminate resistance determinants by horizontal gene transfer.

Tema je mojega diplomskog rada bioremedijacija benzalkonijeva klorida, cikličnog aromatskog ugljikovodika koji služi kao biocid i kationski surfaktant. Upotrebljava se u prašcima za pranje rublja i omekšivačima za tkanine. Bioremedijacija je svaki proces koji se koristi mikroorganizmima u svrhu vraćanja okoliša u prirodno stanje prije nego što je nastupilo onečišćenje ili zagađenje iz nekog antropogenog izvora. Cilj mojega diplomskog rada jest utvrditi mogu li benzalkonijev klorid razgrađivati prirodno prisutne bakterije iz Jarunskog jezera i jezera u Botaničkom vrtu ili bakterije iz aktivnog mulja, otpadne vode, tla te suspenzije bakterija Pseudomonas fluorescens i Pseudomonas aeruginosa. Nije bilo na pločama s bakterijskim agarom kolonija bakterija P. aeruginosa i P. fluorescens, što znači da te bakterije nisu razgrađivale benzalkonijev klorid. Bakterije iz jezera Jarun i jezera u Botaničkom vrtu nisu razgradile benzalkonijev klorid. Bakterije iz otpadne vode, aktivnog mulja i tla koje smo izolirali u laboratoriju razgradile su benzalkonijev klorid u potpunosti. Bakterije koje su identificirane kao razgrađivači benzalkonijevog klorida jesu Agrobacterium radiobacter, Stenotrophomonas maltophilia i Bacillus cereus. The topic of my graduate thesis is bioremediation of benzalkonium chloride, a cyclic aromatic hydrocarbon that serves as a biocide and a cationic surfactant. It is used in laundry detergents and fabric softeners. Bioremediation is any process that uses microorganisms for the purpose of restoring the environment to a natural state before pollution or contamination from an anthropogenic source occured. The aim of my graduate thesis is to determine whether benzalkonium chloride can be degraded by native bacteria from Lake Jarun and lake in botanical garden or specifically grown bacteria from activated sludge, wastewater, soils and suspensions of Pseudomonas fluorescens and Pseudomonas aeruginosa. It was not on bacterial agar plates any bacterial colonies of P. aeruginosa and P. fluorescens, meaning that these bacteria did not break down benzalkonium chloride. Native bacteria from Jarun lake and lake in the botanical garden did not degrade benzalkonium chloride either. Bacteria from the waste water, the activated sludge and the soil we isolated in the laboratory degraded the benzalkonium chloride completely. Bacteria identified as benzalkonium chloride degraders were Agrobacterium radiobacter, Stenotrophomonas maltophilia and Bacillus cereus.

Mnoge bakterije mogu postojati kao zajednice vezane na površinu poznate kao biofilmovi. Bakterijski biofilm je sesilna zajednica čije su stanice ireverzibilno povezane sa supstratom i međusobno, te uronjene u matriks izvanstanične polimerne tvari (eng. extracellular polymeric substance, EPS) koji su same stvorile. Istraživanje je bilo usmjereno na statičke sustave biofilma koji su posebno korisni za ispitivanje ranijih stadija formiranja biofilma. Za istraživanje su korištene bakterije Bacillus cereus i Acinetobacter junii. Cilj istraživanja bio je odrediti model rasta biofilma kojeg tvore te vrste bakterija u stacionarnim uvjetima, kao i vizualizirati biofilm, usporediti količine nastalog EPS-a, te usporediti rast planktonskih i imobiliziranih bakterija kroz vrijeme u stacionarnim uvjetima (batch culture) te uvjetima kontinuiranog rasta (continuous culture). Budući da se pratila biomasa bakterija kroz vrijeme i količina nastalog EPS-a, bakterije su se bojale bojilom Alcian blue i Karbol-fuksinom. Zaključeno je da u stacionarnim uvjetima model rasta bakterijskog biofilma koji se odvija u pet faza nije primjenjiv za bakteriju B. cereus, dok je primjenjiv za bakteriju A. junii. Također je zaključeno da stacionarni uvjeti pogoduju vrsti B. cereus, dok kod bakterije A. junii nema značajne razlike u uvjetima kontinuiranog rasta i u stacionarnim uvjetima. Many bacteria may exist as surfaces-related communities known as biofilms. Bacterial biofilm is a sessile community whose cells are irreversibly linked to the substrate and mutually, and immersed in the matrix of extracellular polymeric substances (EPS) that they have created. The research was focused on static biofilm systems that are particularly useful for the early stages of biofilm formation. Bacteria Bacillus cereus and Acinetobacter junii were used for the study. The goal was to determine a model of biofilm created by these bacteria species in stationary conditions. Also, visualize the biofilm, compare the amount of produced EPS and compare the growth of planktonic and immobilized bacteria over time in batch culture and continuous culture. Given that we monitored bacterial biomass through the time and the amount of produced EPS, bacteria were stained with Alcian-blue which dye the EPS and Carbol-fuchsin which dye the cells. It was concluded that in stationary conditions the five stage model of biofilm development is not applicable to B. cereus, but is applicable to A. junii. It was also concluded that stationary conditions were beneficial for the growth of B. cereus, whereas in comparison with A. junii there was no significant difference in the stationary assay relative to the continuous growth assay.

Plazma je parcijalno ionizirani plin kojeg čine ioni, elektroni i nenabijene čestice. Razlikujemo dva tipa plazmi - termalnu i hladnu plazmu. Atmosferski plazmeni mlazovi hladni su tip plazmi, temperature 30-50 °C. Kemijski reaktivnima ih čini stvaranje radikala (O, O3, H2O2, itd.) i UV svjetla u mlazu i području oko mlaza, što omogućuje inaktivaciju širokog spektra mikroorganizama. Tretman hladnim atmosferskim plazmenim mlazom ne predstavlja opasnost za zdravlje ljudi niti okoliš jer su svi plazmeni radikali kratkoživući i djeluju lokalno na mjestu primjene, a uz to je i ekonomski isplativ. U stomatologiji, konvencionalne metode liječenja i prevencije oralnih bolesti (pranje zuba, antibiotici i drugi lijekovi, mehaničko bušenje itd.) su ograničene i mogu dovesti do neželjenih nuspojava, a metode koje uključuju zagrijavanje živih tkiva su opasne. Hladne atmosferske plazme pokazale su se manje destruktivnim tretmanom jer, zahvaljujući niskim temperaturama, ne dolazi do uništavanja zdravog tkiva i uzrokovanja boli, a učinkovite su u ubijanju bakterija. U prehrambenoj industriji postojeće metode dezinfekcije i sterilizacije namirnica i ambalaža bazirane su uglavnom na letalnom djelovanju visokih temperatura na patogene što ograničava njihovu primjenu, a ne-termalne metode većinom su ekonomski neisplativije, opasnije po ljudsko zdravlje i okoliš te mogu negativno utjecati na kvalitetu namirnica. Tretman hladnom atmosferskom plazmom stoga se nudi kao nova i obećavajuća alternativa antimikrobnog tretmana prehrambenih proizvoda. U konzervatorsko-restauratorskoj struci dezinfekcija umjetnina najčešće se vrši kemijskim sredstvima, plinovima ili γ-zračenjem, a većina tretmana štetna je za ljudsko zdravlje i okoliš te ekonomski neisplativa pa se potiče razvoj metoda tretiranja umjetnina hladnim atmosferskim plazmenim mlazovima. Plasma is a partially ionized gas with ions, electrons and uncharged particles. There are two types of plasma: thermal and cold atmospheric plasma. Cold atmospheric pressure plasma jet is type of cold plasma with temperatures between 30-50 °C. Radicals (O, O3, H2O2, etc.) and UV light in jet and area around the jet make them chemically reactive and enable inactivation of a wide spectrum of microorganisms. Treatment with a cold atmospheric plasma jet isn't harmful for human health and environment because all plasma radicals are short-living and act locally at the site of application, and it is financially acceptable. In dentistry, conventional treatments and prevention of oral disease (teeth brushing, antibiotics and other medicines, mechanical drilling etc.) have limitations and may lead to unwanted side effects. Methods that include heating of living tissues are dangerous. Cold atmospheric plasmas have been shown to be less destructive treatment and, because of their low temperatures they don't cause destruction of healthy tissue or pain and are highly efficient at killing bacteria. In the food industry, the existing disinfection and sterilization methods of food and packaging are based mainly on lethal effects of high temperature on pathogens, limiting their use, and non-thermal methods are mostly costly, more dangerous for human health and the environment and can adversely affect the quality of food. Cold atmospheric plasma treatment is therefore offered as a new and promising alternative for antimicrobial treatment of food products. In conservation/restoration, disinfection of artwork is mostly performed by chemicals, gasses or gamma radiation. Current methods are costly and often dangerous for human health and the environment so it is desireable to devolp treatments with cold atmospheric pressure plasma jets.

Bakterijski biofilm je kompleks građen od jedne ili češće više vrsta bakterija koje su ugrađene u matriks izvanstanične polimerne tvari (eng. extracellular polymeric substance EPS) kojeg same proizvode. Takvi bakterijski sustavi rade velike štete kako na medicinskoj opremi, tako i u ljudskim organizmima. Razumijevanje mehanizma formacije viševrsnog biofilma može znatno olakšati razvoj metoda za borbu protiv bakterijskih biofilmova u bolnicama, okolišu ili industrijama. Za istraživanje su korištene bakterije Staphylococcus aureus i Pseudomonas aeruginosa. Cilj istraživanja bio je napraviti model biofilma kojeg tvore te vrste bakterija, vizualizirati ga, usporediti rast bakterija na granici voda – zrak kod uzoraka u kojima se bakterijama mijenja medij s uzorcima u kojima se medij ne mijenja, te usporediti količine proizvedenog EPS-a. Obzirom da se pratila biomasa bakterija na pojedinim područjima na predmetnom stakalcu (vodeni medij, interfaza i zrak), te da se pratila količina nastalog EPS-a, bakterije su se bojile metodama po Gramu i Alcian blue radi bolje vidljivosti EPS-a i usporedbe uzoraka u navedena dva slučaja. Zaključeno je da se većina biofilma nalazi na interfazi, te da mijenjanje medija više pogoduje bakteriji P. aeruginosa, a ne mijenjanje medija više pogoduje bakteriji S. aureus. Bakterija S. aureus u oba slučaja nakon nekog vremena nadvlada bakteriju P. aeruginosa. Bacterial biofilm is a complex of one or more species of bacteria that are embedded within an extracellular matrix composed of extracellular polymeric substances (EPS) produced by the cells. Such bacterial systems are doing significant damage both on medical equipment and in human organisms. Understanding the mechanism of multiple-species biofilm formation can ease the development of methods for bacterial biofilm prevention in hospitals, environment or industry. In this research, bacteria Staphylococcus aureus and Pseudomonas aeruginosa were used. The goal was to determine a model of biofilm created by these bacteria, visualize it, compare the growth of bacteria on air–liquid interface in systems in which the medium was continuously being replenished and when it is not, and compare the amount of produced EPS. Given that we monitored bacterial biomass in different areas (liquid medium, interface and air), and the amount of produced EPS, bacteria were Gram-stained, but also stained with Alcian blue to achieve better visibility of EPS and to compare samples in two aforementioned cases. It was concluded that biofilm is mostly located on the interface and that changing the medium was more beneficial to the growth of P. aeruginosa, while not changing the medium was more beneficial to the growth of S. aureus. Eventually, S. aureus outgrew P. aeruginosa in both cases.

Primjena pesticida poznata je nekoliko tisuća godina, a proizvodnja sintetičkih pesticida započinje polovicom 20. stoljeća. Nakon upotrebe, većina sintetičkih pesticida se dugotrajno zadržava u okolišu te se njihovi ostaci mogu naći u tlima, morskim i vodenim ekosustavima, pitkoj vodi i podzemnim vodonosnicima. Uz to, zabilježen je povećani mortalitet i ugroženost mnogih skupina organizama. Kroz hranidbeni lanac, ostaci pesticida dospijevaju i do ljudi te uzrokuju različite poremećaje i bolesti. Bioremedijacija je ekonomski isplativa i održiva tehnologija koja na ekološki prihvatljiv način tranformira ili uklanja onečišćujuće tvari iz okoliša pomoću bakterija, biljaka, algi ili gljiva. U ovom radu prikazana su istraživanja bioremedijacije s varijabilnim rezultatima uključujujući bioremedijaciju herbicida, diurona i glifosata te insekticida, imidakloprida i acetamiprida, koristeći različite sojeve bakterija i gljiva. Na kraju su istaknuti problemi koji onemogućavaju masovnu primjenu bioremedijacije u prirodi te je njihovo rješenje moguće samo daljnjim istraživanjima. The application of pesticides has been known for several thousand years, and the production of synthetic pesticides began in the mid-20th century. Most synthetic pesticides stay in the environment for a long time after their use and their residues can be found in soils, marine and aquatic ecosystems, drinking water and underground aquifers. Furthermore, increased mortality and endangerment of many groups of organisms is reported. The pesticide residues reach humans through the food chain and cause various disorders and diseases. Bioremediation is a cost-effective and sustainable technology that transforms or eliminates pollutants from the environment by bacteria, plants, algae or fungi in an environmentally friendly way. Bioremediation studies with variable results were presented in this paper, including bioremediation of herbicides, diuron and glyphosate, and insecticides, imidacloprid and acetamiprid, using various bacteria and fungi strains. Finally, problems that prevent the massive application of bioremediation were highlighted and their solution is only possible with further research.

Forenzična znanost uključuje upotrebu znanosti u istraţivanjima pravnih i političkih pitanja. Mikrobiološka forenzika je znanstvena disciplina posvećena analizi mikroorganskih dokaza iz bioterorizma, biozločina ili tragova vezanih uz druge zločine. U ovom radu izloţen je kratki pregled mikroorganizama, ponajviše bakterija, gljiva i dijatomeja uključenih u forenzična istraţivanja. U istraţivanjima se najčešće spominju bakterije reda: Actinobacteria, Firmicutes i Proteobacteria. U slučaju utapanja najbitnije su dijatomeje, a gljive su uz bakterije glavni stanovnici ljudskih i ţivotinjskih leševa. Najvaţnije je pravilno prikupiti uzorke, te odrediti post mortem interval, nakon čega moţemo zaključiti o kakvoj se vrsti zločina radi. Primjena mikroorganizama i njihovih toksina s nakanom ozljeĎivanja, razbolijevanja ili ubijanja ljudi, ţivotinja ili biljaka, područje je kojim se bavi bioterorizam. Forensic science involves the application of science to the investigation of legal and policy matters. Microbial forensics is a scientific discipline dedicated to analyzing micoorganisms evidences from a bioterrorism , biocrime, or traces of other crimes. This paper presents a brief overview of microorganisms, mostly bacteria, fungi and diatoms involved in forensic investigations. There are three phyla that have been observed regularly: Actinobacteria, Firmicutes i Proteobacteria.In the case of drowning the most important is diatoms.Fungi and bacteria are the main inhabitants of human and animals corpses. It is most important to collect the samples correctly and to determine the post-mortem interval, after which we can conclude what kind of crime it is.The application of microorganisms and their toxins with the intent of injuring, abusing or killing people, animals or plants, is an area of bioterrorism.

Procjena antimikrobne aktivnosti tekstilnih materijala se provodi standardiziranim metodama koje donose različite organizacije za standardizaciju jedna od kojih je i ISO – Internacionalna organizacija za standardizaciju. Ciljevi ovog istraživanja su bili uvođenje i optimizacija ISO 20743:2013 i ISO 20645:2004 standarda za određivanje antibakterijske aktivnosti tekstilnih materijala u Laboratorij za bakteriologiju na Zavodu za mikrobiologiju Prirodoslovno-matematičkog fakulteta te određivanje antibakterijske aktivnosti materijala načinjenih na Tekstilno-tehnološkom fakultetu u sklopu projekta „Udobnost i antimikrobna svojstva tekstila i odjeće“ Hrvatske zaklade za znanost. Istraženi materijali su pamuk, sirova i obojena viskoza, tencel, mikromodal, modal, materijal X, materijal sa srebrom Aquacel Ag i antibakterijski uložak za cipele. Aquacel Ag, materijal X i uložak su pokazali antibakterijska svojstva na vrstama Staphylococcus aureus i Escherichia coli u sve tri korištene metode, a modal i mikromodal u dvije metode. Obojena i sirova viskoza su imale antibakterijska svojstva u jednoj od metoda za svaku bakteriju, a pamuk samo na vrsti E. coli u jednoj metodi. Tencel nije pokazao značajnija antibakterijska svojstva. Da bi se dobio točan rezultat, potrebno je paralelno koristiti nekoliko metoda i ispitati bar dvije vrste bakterija, jer se na temelju samo jedne vrste i jedne metode može pogrešno zaključiti o antibakterijskim svojstvima materijala. An assessment of the antimicrobial activity of textile materials is carried out by standardized methods that are provided by different organizations, such as ISO - International Organization for Standardization. The aim of this study was to introduce and optimize ISO 20743: 2013 and ISO 20645:2004 standards for the determination of antibacterial activity of textile materials in the Bacteriological Laboratory at the Department of Microbiology of the Faculty of Science and to determine the antibacterial activity of materials made at the Faculty of Textile Technology as part of the project "Textiles and footwear comfort and antimicrobial properties". The investigated materials were cotton, crude and dyed viscose, tencel, micromodal, modal, material X, silver-containing material Aquacel Ag and antibacterial insoles for shoes. Aquacel Ag, material X and antibacterial insoles showed antibacterial properties against Staphylococcus aureus and Escherichia coli in all three methods, and modal and micromodal in the two applied methods. Dyed and crude viscose had antibacterial properties in one of the methods for each bacterium, and cotton only against E. coli in one method. Tencel showed no significant antibacterial properties. In order to obtain precise and relevant result, it is necessary to use several methods and at least two bacteria species, because only one species and one method can misconstrue the antibacterial properties of a material.

Bakterija Bacillus cereus je Gram-pozitivna, pokretljiva, štapićasta bakterija koja može biti obligatno aerobna ili fakultativno anaerobna te spada u rod Bacillus. Sveprisutna je u prirodi te je tipični saprofit tla i lako se širi na različite tipove hrane. Endospore su jako hidrofobne i izuzetno otporne na velik broj stresora. Uz to uzrokuje probleme i zbog svoje sposobnosti stvaranja biofilma na različitim supstratima. Bakterijski biofilm je višestanični kompleks formiran od sesilnih zajednica mikroorganizama pričvršćenih na podlogu i uronjenih u matriks koji se sastoji od izvanstaničnih polimernih tvari. Matriks im pruža mehaničku stabilnost, štiti ih od isušenja, djeluje kao prepreka protiv nepovoljnih kemijskih i bioloških utjecaja te pridonosi apsorpciji i skladištenju hranjivih tvari. Glavni cilj ovog istraživanja bio je razviti model stvaranja biofilma bakterije B. cereus na granici voda-zrak te je dokazano da interfaza služi kao mjesto širenja velike količine vegetativnih stanica i endospora. Uz to je potvrđeno da je granica voda-zrak povoljno područje za razvoj i razmnožavanje aerobne ili fakultativno anaerobne bakterije poput B. cereus jer joj pruža pristup kisiku u plinovitoj fazi i hranjivim tvarima u vodenoj fazi. Bacillus cereus is a Gram-positive, motile, rod-shaped bacterium that may be obligatory aerobic or facultatively anaerobic and belongs to the genus Bacillus. It is ubiquitously present in nature and is a typical soil saprofit that easily spreads to different types of food. Endospores are highly hydrophobic and extremely resistant to a large number of stressors. It also cause problems because of its ability to create biofilms on different substrates. Bacterial biofilm is a multicellular complex formed by sessile microorganisms attached to the substrate and immersed in a matrix consisting of extracellular polymeric substances. The matrix provides them with mechanical stability, protects them from desiccation, acts as an obstacle to adverse chemical and biological influences and contributes to the absorption and storage of nutrients. The main purpose of this study was to develop a model for biofilm formation of B. cereus at air-liquid interface and it was proven that the interface serves as a nidus for spreading large amounts of vegetative cells and endospores. It is confirmed that the air-liquid interface is a favorable area for the development and propagation of aerobic or facultatively anaerobic bacteria such as B. cereus because it provides access to oxygen (gaseous) and nutrients (liquid phase).

Biofilm je sve aktualnija tema i sve više se istražuje, a veće razumijevanje biofilma trebalo bi dovesti do novih, učinkovitijih strategija kontrole i poboljšanja liječenja pacijenata. Trend porasta rezistentnosti biofilma na antibiotike postaje sve ozbiljniji problem, a rješenje se pokušava pronaći kombinacijom različitih mjera poput izbjegavanja infekcija, blokiranja bakterijskih čimbenika virulencije ili pojačavanja imunološke obrane domaćina, potiskujući bakterije u biofilmu na prethodnu ulogu kao fakultativne ili rijetko patogene bakterije. Cilj rada je bio opisati najznačajnija svojstva biofilma: od procesa njegovog nastajanja, preko rasprostiranja u okoliš, kao uzročnika virulencije kod bakterija te rezistentnosti na antibiotike. Težište rada bilo je na biofilmovima koji su nastali djelovanjem bakterije Acinetobacter baumannii. Biofilm is an important topic and there is more and more research in this area. A better understanding of biofilm should lead to new, more effective strategies for controlling and improving treatment of patients. The increasing trend of a biofilm resistance to antibiotic treatment become more and more serious problem, and the solution is to find a combination of different measures such as avoiding infections, blocking the factors of a bacterial virulence, or the host immunity increasing by suppressing bacterial cells in biofilm to reduce their pathogenicity. The aim of the paper was to describe the most important biofilm properties: from the process of its formation, through migration to the environment, as a bacterial virulence agent and and biofilm antibiotic resistance. The focus of the theses was on biofilms produced by the Acinetobacter baumannii.

Teški metali zbog svoje toksičnosti, stabilnosti i sklonosti nakupljanja u živim organizmima, predstavljaju ozbiljni ekološki problem. Stoga ih je potrebno ukloniti iz otpadnih voda prije ispuštanja u prirodni prijemnik. Prirodni zeolitni tuf pokazao se kao pogodan materijal s velikim kapacitetom vezanja iona Cu2+ iz otpadnih voda. U radu je ispitana antibakterijska aktivnost zeolitnog tufa koji sadrži 2,60 % masenog udjela (eng. percentage by weight, wt.%) Cu2+ u odnosu na bakterije Escherichia coli i Staphylococcus aureus, nakon 1 h i 24 h kontakta s zeolitom u tri vodena medija: hranjivom mediju Luria Bertani (LB), sintetskoj otpadnoj vodi i realnoj otpadnoj vodi. Utvrđeno je da zeolitni tuf obogaćen bakrom pokazuje antibakterijsku aktivnost u odnosu na Gram - pozitivnu bakteriju Staphylococcus aureus i Gram - negativnu bakteriju Escherichia coli. Nakon 24 h kontakta dolazi do redukcije broja bakterija u sintetskoj (87,35 – 95,67%) i realnoj otpadnoj vodi (86,79 – 93,54%), dok u Luria Bertani (LB) mediju (5,54 – 10,69%) redukcija nije bila učinkovita. Ne dolazi do izlučivanja toksičnih Cu2+ iona u vodenu otopinu što zeolit s Cu2+ čini obećavajućim antibakterijskim materijalom za dezinfekciju otpadnih voda. Heavy metals pollution is one of the most important environmental problems, due of their toxicity, stability, and tendency to accumulate in living organisms. Therefore, heavy metals should be removed from the wastewater before it can be discharged into a natural recipient. Natural zeolitized tuff was proved to be a suitable material with high capacity binding of Cu 2+ ions from wastewater. The antibacterial activity of natural zeolitized tuff containing 2.60 percentage by weight (wt.%) Cu2+ were tested against bacteria Escherichia coli and Staphylococcus aureus after 1 h and 24 h of contact with zeolit in three different media, namely: Luria Bertani (LB) medium, synthetic wastewater and real wastewater. The copper – loaded zeolitized tuff showed antibacterial activity against Gram - positive bacteria Staphylococcus aureus and Gram - negative bacteria Escherichia coli, after 24 h of contact. The reduction of bacterial numbers was efficient in synthetic water (87,35 – 95,67%) and real effluent water (86,79 – 93,54%), while in the Luria Bertani (LB) medium the reduction was not efficient (5,54 – 10,69%). Since there was not leaching of toxic Cu2 + ions in the aqueous solution, Cu - loaded zeolite can be regarded as promising antibacterial material for disinfection of wastewater.

U svijetu dolazi do sve većeg ispuštanja otpadnih voda. Razlog tome je rast svjetske populacije i ubrzana industrijalizacija. Kao protumjera zagađenja uzrokovanog razvitkom ljudske civilizacije, traže se nove, učinkovite i isplative metode pročišćavanja voda. Kao jedan od mnogo rezultata takvih protumjera, nastala je metoda pročišćavanja voda bakterijama imobiliziranim u biofilmove na minerale zeolita. Ovaj rad govori o potencijalu korištenja takve metode za pročišćavanje voda, o njenim prednostima i nedostacima, kao i što pokušava obuhvatiti širinu mogućnosti i varijabli koje utječu na rezultate. U ovom radu se govori o fosfatima jer su fosfati jedan od najraširenijih oblika zagađivala diljem svijeta. Također se govori o organizmima koji su adekvatni za uklanjanje fosfata iz vode, konkretno o fosfat – akumulirajućim bakterijama iz roda Acinetobacter, te o raznim mineralima iz skupine zeolita koji bi potencijalno služili kao dobra podloga za imobilizaciju navedene bakterije. In the world there is an increasing discharge of waste water. The reason for this is the growth of world population and rapid industrialization. As a countermeasure for pollution caused by the development of human civilization, there is a search for new, efficient and cost-effective methods of purifying water. One of the many results of such countermeasures, was development of the method of purifying water with immobilized bacteria in biofilms on mineral zeolite. This article talks about the potential of using such a method for the purification of water, and also talks about its advantages and disadvantages, as well as trying to cover the breadth of capabilities and variables that affect the results. This paper discusses the phosphates as they are the one of the most widespread pollutants worldwide. Also discussed are the organisms that are adequate for removing phosphate from the water, in particular the bacteria of the genus Acinetobacter. Paper also discusses various minerals from the group of zeolites which could potentially serve as a good surface for said bacteria.

Acinetobacter baumannii su gram negativne, katalaza pozitivne i strogo aerobne bakterije koje su razvile visoku rezistenciju na gotovo sve grupe antibiotika. Imaju veliku sposobnost brze prilagodbe na okolišni stres, te upravo stoga i predstavljaju sve veću prijetnju. Mehanizmi rezistencije se većinom temelje na pokretnim genskim elementima: transpozonima, integronima i 'insertion sequence' elementima. Oni pomažu u stvaranju rezistencije na sljedeće antibiotike: aminoglikozide, ß-laktame, kinolone, polimiksine, tetracikline i glicilcikline. Osim ovih mehanizama, u radu su opisane i molekularne metode analize i detekcije sojeva A. baumannii (analiza plazmida, ribotipizacija, metode temeljene na PCR-u, PFGE, AFLP i MLST metoda), te kliničke manifestacije infekcija sa gore navedenom bakterijom (upala pluća, infekcije krvnog toka i urinarnog trakta, meningitis). Acinetobacter baumannii are gram-negative, catalase-positive and strictly aerobic bacteria who have developed high resistance on almost every type of antibiotic. They have high ability for adaption on enviromental stress and, because of this, they present big threat in health institutions. Resistance mechanisms are mostly based on mobile genetic elements: transposons, integrons and insertion sequence elements. They are helping in creation of resistance at different types of antibiotics: aminoglycosides, ß-lactams, quinolones, polymyxins, tetracyclines and glycylcyclines. Except this mechanisms, in this work are described methods for moleclar analysis and detection of A.baumannii strains (plasmid analysis, ribotyping, PCR-based typing methods, PFGE, AFLP and MLST). Also, there is short reference to clinical manifestations of A.baumannii infections.