Antibakterijsko djelovanje fulerena

Fulereni su grupa spojeva slučajno otkrivenih 1985. godine. Struktura im je nalik na zakrivljeni ikozaedar s ugljikovim atomima na svakom vrhu. Posjeduju 12 pentagonalnih i različit broj heksagonalnih prstena. U kemijskim reakcijama se ponašaju kao alkeni, zbog toga reagiraju s elektron bogatim spojevima. Fulereni imaju brojne derivate kao što su endoedarski, egzoedarski fulereni i nanocijevi, zbog toga posjeduju brojne primjene od superkonduktora do biološki korisnih molekula. U krutom obliku fulereni ne iskazuju antibakterijsku aktivnost, nego jedino u obliku vodenih suspenzija. Na bakterijama se uočavaju promjene u membranskom potencijalu i u stvaranju ATP-a, jer fulereni djeluju kao oksidanti tih proteina. Povećava se udio masnih trans kiselina i ciklopropanske kiseline, jer se na taj način bakterije pokušavaju zaštititi. Fulereni ne perforiraju stanicu niti oštećuju staničnu membranu. Smatra se da inicijalno otapalo, koje je služilo za pripremu vodene suspenzije fulerena pridonosi antibakterijskom djelovanju.Fullerens are a group of compounds accidentally discovered in 1985. Their structure is like a curved icosahedron with carbon atoms at every top. They have 12 pentagonal and a different number of hexagonal rings. In chemical reactions they act like alkenes, because of that they react with electron rich compounds. Fullerens have a large number of derivatives like endohedral, exohedral fullerens and nanotubes, because of that they have many applications, from superconductors to biologicaly useful molecules. In solid form fullerens do not exibit antibacterial activity, but only in a form of fullerene water suspensions. Bacteria show changes in membrane potential and in creation of ATP, because fullerens are strong oxidants of these proteins. The amount of fatty trans acids and cyclopropane fatty acids increases, because that is a bacterial defense mechanism. Fullerens do not perforate the cell nor do they damage the cell membrane. It is considered that the initial solvent, which was used for the preparation of fullerene water suspensions contributes to the antibacterial effect

Antibakterijsko djelovanje fulerena

Fulereni su grupa spojeva slučajno otkrivenih 1985. godine. Struktura im je nalik na zakrivljeni ikozaedar s ugljikovim atomima na svakom vrhu. Posjeduju 12 pentagonalnih i različit broj heksagonalnih prstena. U kemijskim reakcijama se ponašaju kao alkeni, zbog toga reagiraju s elektron bogatim spojevima. Fulereni imaju brojne derivate kao što su endoedarski, egzoedarski fulereni i nanocijevi, zbog toga posjeduju brojne primjene od superkonduktora do biološki korisnih molekula. U krutom obliku fulereni ne iskazuju antibakterijsku aktivnost, nego jedino u obliku vodenih suspenzija. Na bakterijama se uočavaju promjene u membranskom potencijalu i u stvaranju ATP-a, jer fulereni djeluju kao oksidanti tih proteina. Povećava se udio masnih trans kiselina i ciklopropanske kiseline, jer se na taj način bakterije pokušavaju zaštititi. Fulereni ne perforiraju stanicu niti oštećuju staničnu membranu. Smatra se da inicijalno otapalo, koje je služilo za pripremu vodene suspenzije fulerena pridonosi antibakterijskom djelovanju.Fullerens are a group of compounds accidentally discovered in 1985. Their structure is like a curved icosahedron with carbon atoms at every top. They have 12 pentagonal and a different number of hexagonal rings. In chemical reactions they act like alkenes, because of that they react with electron rich compounds. Fullerens have a large number of derivatives like endohedral, exohedral fullerens and nanotubes, because of that they have many applications, from superconductors to biologicaly useful molecules. In solid form fullerens do not exibit antibacterial activity, but only in a form of fullerene water suspensions. Bacteria show changes in membrane potential and in creation of ATP, because fullerens are strong oxidants of these proteins. The amount of fatty trans acids and cyclopropane fatty acids increases, because that is a bacterial defense mechanism. Fullerens do not perforate the cell nor do they damage the cell membrane. It is considered that the initial solvent, which was used for the preparation of fullerene water suspensions contributes to the antibacterial effect

Antibakterijsko djelovanje fulerena

Fulereni su grupa spojeva slučajno otkrivenih 1985. godine. Struktura im je nalik na zakrivljeni ikozaedar s ugljikovim atomima na svakom vrhu. Posjeduju 12 pentagonalnih i različit broj heksagonalnih prstena. U kemijskim reakcijama se ponašaju kao alkeni, zbog toga reagiraju s elektron bogatim spojevima. Fulereni imaju brojne derivate kao što su endoedarski, egzoedarski fulereni i nanocijevi, zbog toga posjeduju brojne primjene od superkonduktora do biološki korisnih molekula. U krutom obliku fulereni ne iskazuju antibakterijsku aktivnost, nego jedino u obliku vodenih suspenzija. Na bakterijama se uočavaju promjene u membranskom potencijalu i u stvaranju ATP-a, jer fulereni djeluju kao oksidanti tih proteina. Povećava se udio masnih trans kiselina i ciklopropanske kiseline, jer se na taj način bakterije pokušavaju zaštititi. Fulereni ne perforiraju stanicu niti oštećuju staničnu membranu. Smatra se da inicijalno otapalo, koje je služilo za pripremu vodene suspenzije fulerena pridonosi antibakterijskom djelovanju.Fullerens are a group of compounds accidentally discovered in 1985. Their structure is like a curved icosahedron with carbon atoms at every top. They have 12 pentagonal and a different number of hexagonal rings. In chemical reactions they act like alkenes, because of that they react with electron rich compounds. Fullerens have a large number of derivatives like endohedral, exohedral fullerens and nanotubes, because of that they have many applications, from superconductors to biologicaly useful molecules. In solid form fullerens do not exibit antibacterial activity, but only in a form of fullerene water suspensions. Bacteria show changes in membrane potential and in creation of ATP, because fullerens are strong oxidants of these proteins. The amount of fatty trans acids and cyclopropane fatty acids increases, because that is a bacterial defense mechanism. Fullerens do not perforate the cell nor do they damage the cell membrane. It is considered that the initial solvent, which was used for the preparation of fullerene water suspensions contributes to the antibacterial effect

Influence of ecological factors on virulence properties of clinically relevant Acinetobacter baumannii

Bakterija Acinetobacter baumannii uzrokuje teńke infekcije imunosuprimiranih bolesnika zbog otpornosti na antibiotike i dezinficijense te posjedovanja brojnih faktora virulencije. Multiplo-rezistentni sojevi ove bakterije osim u bolničkom, pojavljuju se i u izvanbolničkom okolińu. Cilj disertacije bio je definirati ekolońke čimbenice koji uvjetuju preņivljavanje klinički značajnih A. baumannii u okolińu. Ispitivano je preņivljavanje okolińnih i kliničkih izolata A. baumannii u različitim abiotičkim (temperatura, pH, dostupnost nutrijenata, koncentracija otopljenog kisika, isuńivanje) i biotičkim (interakcija s mikroskopskim organizmima) uvjetima. TakoĎer su kvantificirani faktori virulencije (biofilm, pelikula, povrńinska pokretljivost) kao mehanizmi koji pospjeńuju preņivljavanje A. baumannii. Klinički značajni izolati A. baumannii posjeduju izraņene faktore virulencije te su otporni na ńirok spektar okolińnih uvjeta. Prirodni zeoliti uspjeńno inhibiraju faktore virulencije A. baumannii te kao ekonomski prihvatljivi i dostupni materijali mogu pronaći primjenu u uklanjanju ovog patogena iz okolińa. Rezultati ovog istraņivanja omogućuju predviĎanje ponańanja A. baumannii u okolińu te pruņaju osnovu za razvoj metoda uklanjanja ovog patogena iz okolińa.Acinetobacter baumannii causes severe infections in immunosuppressed patients due to resistance to antibiotics and disinfectants. Multidrug resistant A. baumannii isolates are common in hospital setting but also in the environment. The aim was to determine which ecological factors contribute to the survival of clinically relevant A. baumannii in the environment. The survival of clinical and environmental A. baumannii isolates was tested under different abiotic (temperature, pH, starvation, dissolved oxygen concentration, dessication) and biotic (interaction with microscopic organisms) conditions. Virulence factors (biofilm, pellicle, surface motility) as survival mechanisms were also determined. Clinically relevant A. baumannii express strong virulence factors and are able to survive a wide array of ecological conditions. Natural zeolites successfully inhibit A. baumannii virulence factors and as economically accessible materials could find application in the removal of this pathogen from the environment. The results of this research provide insight into the behaviour of A. baumannii as well as a starting point for the development of methods to remove this pathogen from the environment

Influence of ecological factors on virulence properties of clinically relevant Acinetobacter baumannii

Bakterija Acinetobacter baumannii uzrokuje teńke infekcije imunosuprimiranih bolesnika zbog otpornosti na antibiotike i dezinficijense te posjedovanja brojnih faktora virulencije. Multiplo-rezistentni sojevi ove bakterije osim u bolničkom, pojavljuju se i u izvanbolničkom okolińu. Cilj disertacije bio je definirati ekolońke čimbenice koji uvjetuju preņivljavanje klinički značajnih A. baumannii u okolińu. Ispitivano je preņivljavanje okolińnih i kliničkih izolata A. baumannii u različitim abiotičkim (temperatura, pH, dostupnost nutrijenata, koncentracija otopljenog kisika, isuńivanje) i biotičkim (interakcija s mikroskopskim organizmima) uvjetima. TakoĎer su kvantificirani faktori virulencije (biofilm, pelikula, povrńinska pokretljivost) kao mehanizmi koji pospjeńuju preņivljavanje A. baumannii. Klinički značajni izolati A. baumannii posjeduju izraņene faktore virulencije te su otporni na ńirok spektar okolińnih uvjeta. Prirodni zeoliti uspjeńno inhibiraju faktore virulencije A. baumannii te kao ekonomski prihvatljivi i dostupni materijali mogu pronaći primjenu u uklanjanju ovog patogena iz okolińa. Rezultati ovog istraņivanja omogućuju predviĎanje ponańanja A. baumannii u okolińu te pruņaju osnovu za razvoj metoda uklanjanja ovog patogena iz okolińa.Acinetobacter baumannii causes severe infections in immunosuppressed patients due to resistance to antibiotics and disinfectants. Multidrug resistant A. baumannii isolates are common in hospital setting but also in the environment. The aim was to determine which ecological factors contribute to the survival of clinically relevant A. baumannii in the environment. The survival of clinical and environmental A. baumannii isolates was tested under different abiotic (temperature, pH, starvation, dissolved oxygen concentration, dessication) and biotic (interaction with microscopic organisms) conditions. Virulence factors (biofilm, pellicle, surface motility) as survival mechanisms were also determined. Clinically relevant A. baumannii express strong virulence factors and are able to survive a wide array of ecological conditions. Natural zeolites successfully inhibit A. baumannii virulence factors and as economically accessible materials could find application in the removal of this pathogen from the environment. The results of this research provide insight into the behaviour of A. baumannii as well as a starting point for the development of methods to remove this pathogen from the environment

Doprinos poznavanju faune vodencvjetova Hrvatske (Insecta: Ephemeroptera)

Caenis lactea (Burmeister, 1839) from the family Caenidae has been recorded for the first time in Croatia in the reservoirs of HPP Dubrava and Čakovec on the Drava River. Additionally, new data on distribution of the species Heptagenia longicauda (Stephens, 1836) and Ephemerella mucronata (Bengtsson, 1909) are presented.Vrsta Caenis lactea (Burmeister, 1839) iz porodice Caenidae po prvi puta je zabilježena u Hrvatskoj u akumulacijama HE Dubrava i Čakovec na rijeci Dravi. Također, u radu su prikazani i novi podaci o rasprostranjenosti vrsta Heptagenia longicauda (Stephens, 1836) i Ephemerella mucronata (Bengtsson, 1909)

Nalazi invazivnog rakušca Echinogammarus ischnus (Stebbing, 1899) u Hrvatskoj

The Ponto-Caspian alien and invasive amphipod, Echinogammarus ischnus (Stebbing, 1899), was found in Croatia at three sites in the lower course of the Drava River and at three sites in the Danube River (Batina, Borovo and Ilok). The most upstream site in the Drava where the species was found is a locality near Donji Miholjac, approximately 82 km upstream from the confluence with the Danube River. At this site as well as at two downstream sites (Osijek and Belišće) in Drava it was found together with the dominant invasive amphipods Dikerogammarus villosus and Chelicorophium curvispinum, while at the Donji Miholjac site it also co-occurs with two native species, Gammarus fossarum and G. roeseli.Ponto-kaspijski strani i invazivni rakušac Echinogammarus ischnus (Stebbing, 1899), pronađen je u Hrvatskoj u donjem toku rijeke Drave i na tri lokaliteta u Dunavu (Batina, Borovo i Ilok). Najuzvodnija postaja na kojoj je nađen u Dravi, kod mjesta Donji Miholjac, udaljena je otprilike 82 km od ušća u Dunav. Na toj, kao i na dvije nizvodne postaje (Osijek i Belišće) u Dravi, zabilježen je zajedno s druge dvije invazivne vrste rakušaca Dikerogammarus villosus i Chelicorophium curvispinum, dok na postaji kod Donjeg Miholjca uz ove dvije dominantne strane vrste dolazi zajedno s još dvije autohtone vrste Gammarus fossarum i G. roeseli

Survival of Acinetobacter baumannii in different water types

Acinetobacter baumannii je oportunistički patogen koji izaziva infekcije imunosuprimiranih bolesnika. S obzirom da je nedovoljno podataka o uspješnosti preživljavanja ovog patogena u prirodnom okolišu, cilj rada bio je odrediti stopu preživljavanja A. baumannii u različitim tipovima voda. Tri izolata A. baumannii višestruko rezistentnih na antibiotike inokulirana su u izvorsku, morsku i izlaznu vodu (efluent) uređaja za pročišćavanje otpadnih voda, te inkubirana na 20°C tijekom 50 dana. U izvorskoj vodi broj vijabilnih A. baumannii bio je konstantan sa stopom preživljavanja 92% nakon 50 dana. U morskoj vodi zabilježen je pad broja bakterija sa stopom preživljavanja 67% nakon 50 dana. U efluentu je došlo do umnažanja bakterija, te je broj A. baumannii bio veći od inicijalnog broja i nakon 50 dana praćenja. Umnažanje te bolje preživljavanje A. baumannii u efluentu u odnosu na izvorsku ili morsku vodu objašnjava se većom dostupnošću nutrijenata. A. baumannii višestruko rezistentni na antibiotike sposobni su preživjeti u različitom vodenom okolišu kroz duže vrijeme, što predstavlja mogućnost njihovog širenja putem voda u prirodni okoliš.Acinetobacter baumannii is an opportunistic bacterial pathogen which causes infections in immunosuppressed patients. Considering insufficient data on the survival success rate of this pathogen in the natural environment, the purpose of this paper was to determine the A. baumannii survival rate in different water types. Three A. baumannii isolates with multiple antibiotic resistance multiply were inoculated in spring water, sea water and wastewater treatment plant effluent and incubated on 20°C in the period of 50 days. The number of viable A. baumannii in spring water was constant, with a survival rate of 92% after 50 days. In sea water, there was a recorded decrease of the bacterial numbers with a survival rate of 67% after 50 days. The bacteria in the effluent multiplied, and the number of A. baumannii was higher than the initial number even after 50 days of monitoring. The multiplication of bacteria and improved survival of A. baumannii in the effluent in comparison to spring or sea water is attributed to higher nutrient availability. A. baumannii with multiple antibiotic resistance can survive in different aquatic environments for a longer time period, which provides an opportunity for its spreading through water into the natural environment

Bacteriological analysis of spring water in the vicinity of popular visitor spots in the Nature Park Medvednica

Unutar Parka prirode Medvednica postoje brojni izvori pitke vode. Cilj ovog istraživanja bio je odrediti je li voda iz odabranih izvora uz popularna izletišta u trenutku uzorkovanja pogodna za piće. Uzorci vode sakupljeni su 11. prosinca 2016. iz izvora Vidovec, Baćun, Bliznec, izvora na vrhu Leustekove staze i iz Kraljičinog zdenca. Određen je broj ukupnih heterotrofnih bakterija, fekalnih koliforma, crijevnih enterokoka i bakterija roda Pseudomonas te koncentracija suspendiranih čestica i pH vode. Rezultati analize upućuju da je u trenutku uzorkovanja voda iz izvora Vidovec, Baćun i Bliznec bila pogodna za piće. Voda iz izvora na vrhu Leustekove staze zbog prevelikog broja heterotrofa i voda iz Kraljičinog zdenca zbog jednog nalaza bakterije Escherichia coli u trenutku uzorkovanja nije bila pogodna za piće. Kako bi dobili potpuniju sliku o tome je li voda s istraživanih izvora pogodna za piće potrebno je provesti sustavno praćenje kvalitete vode.There are numerous freshwater springs within the Nature Park Medvednica. The purpose of this investigation was to determine whether water from selected springs close to popular visitor spots is suitable for drinking at the sampling time. Water samples were collected on 11 December 2016 from the springs Vidovec, Baćun, Bliznec, the spring at the top of the Leustek trail and from the Queen\u27s Well. The number of total heterotrophic bacteria, faecal coliforms, intestinal enterococci and bacteria of the genus Pseudomonas as well as the concentrations of suspended solids and pH of water were determined. The analysis results indicate that water from the springs Vidovec, Baćun and Bliznec was suitable for drinking at the sampling time, whereas water from the spring at the top of the Leustek trail (due to excessive heterotrophic bacteria numbers) and water from the Queen\u27s Well (due to Escherichia coli found in one sample) were unsuitable for drinking at the sampling time. In order to gain a more comprehensive insight regarding the suitability for drinking of water from the investigated springs, a systemic monitoring of water quality should be performed