Structural Analysis of a Water Molecule and Its Physical Properties

Voda (H2O) je polarni anorganski spoj, koji je na sobnoj temperaturi tekućina bez okusa i mirisa, gotovo bezbojna. Količinski je daleko najzastupljeniji spoj na Zemlji i među rijetkim je tvarima koje na Zemljinoj površini postoje u krutoj, tekućoj i plinovitoj fazi. Kao relativno jednostavan kemijski spoj, opisana je kao „univerzalno otapalo“ ili „otapalo života“. Ujedno je i treća najzastupljenija molekula u Svemiru. Molekule vode međusobno tvore snažne vodikove veze, što joj definira specifična fizikalna i kemijska svojstva. Vodikove veze zaslužne su za mnoga jedinstvena svojstva vode, poput anomalije vode (činjenice da je kruti oblik – led – manje gustoće od tekuće vode), relativno visoke temperature vrenja (100 °C) i velikog toplinskog kapaciteta, što su ključni preduvjeti za očuvanje života na Zemlji. Voda je amfoterna molekula, što znači da može pokazivati svojstva i kiseline i lužine, ovisno o kemijskom okruženju u kojem se nalazi. U radu je provedena strukturna analiza molekule vode i njenih najvažnijih fizikalnih svojstava, s naglaskom na anomaliju vode. Jedno od važnih fizikalnih svojstava tekućine, a koja uvelike utječu na naš okoliš, je niska gustoća leda u odnosu na tekuću fazu vode te fenomen negativnog koeficijenta ekspanzije hladne vode. Također je opisano rješenje nuklearne Schrödingerove jednadžbe, koja daje informacije o unutarnjim gibanjima (vibracijama i rotaciji) molekule vode.Water (H2O) is a polar inorganic compound that is almost colorless at room temperature. It is by far the most common substance on Earth and among very few substances, which exists on the Earth’s surface as a solid, liquid and gaseous substance. As a relatively simple chemical compound, it has been described as a “universal solvent” or “solvent of life”. It is also the third most common molecule in the Universe. Water molecules form strong polar hydrogen bonds with each other, which, in turn, define its specific physical and chemical properties. Hydrogen bonds are responsible for many unique properties such as the anomaly of water (the fact that its solid form, the ice, is less dense than the liquid form), a relatively high boiling point (100 °C) and a high heat capacity. Water is an amphoteric molecule, which means that it can show properties of both acids and alkaline solutions, depending on the chemical environment. In this paper, a structural analysis of a water molecule and its most important physical properties was carried out in detail with regard to its anomalies. One of the important physical properties of a liquid that strongly influences our environment is the low density of ice in relation to the liquid phase of water, and the phenomenon of the negative expansion coefficient of cold water. This work also describes the solutions of the nuclear Schrödinger equations, which provide information about the internal motions (vibrations and rotations) of a water molecule.</p

Antibacterial properties of honey

Globalni problem bakterijske rezistencije na antibiotike uzrok je potrage za novim antimikrobnim lijekovima. Zbog toga se mnogo očekuje od meda koji ima antimikrobno djelovanje na bakterije otporne na djelovanje antibiotika. Za antibakterijsku aktivnost meda odgovorno je više komponenti prisutnih u medu, u koncentracijama koje se razlikuju kod raznih vrsti meda. Nepredvidiva antibakterijska aktivnost meda, koja nije standardizirana, može otežati njegovu primjenu kao antimikrobnog agensa radi uočenih varijacija u in vitro antibakterijskoj aktivnosti različitih vrsta meda. Trenutačno se na tržištu može naći nekoliko vrsti meda sa standardiziranim razinama antibakterijskog djelovanja, od kojih je najpoznatiji med manuke (lat. Leptospermum scoparium).The global problem of antimicrobial resistance in bacterial pathogens increases the need for new antimicrobial agents. Therefore, honey with effective antimicrobial properties against antibiotic-resistant bacteria is much anticipated. Antibacterial activity of honey is very complex due to the involvement of multiple compounds and variations in their concentrations among different honeys. The unpredictable antibacterial activity of non-standardized honey may hamper its introduction as an antimicrobial agent due to variations in the in vitro antibacterial activity of various honeys. At present, a number of honeys are put to the market with standardized levels of antibacterial activity, of which the best known is manuka (lat. Leptospermum scoparium) honey

Survival of bacteria on dry surfaces in the hospital environment

Prijenos uzročnika infekcija rukama bolničkog osoblja vodeći je način prijenosa bolničkih infekcija. Uzročnici infekcija na ruke mogu dospjeti izravnim kontaktom osoblja s pacijentom, ali i kontaktom s različitim površinama u zdravstvenoj ustanovi. Bakterije koje su najčešći uzročnici bolničkih infekcija mogu mjesecima preživjeti na različitim površinama i materijalima koji tako mogu postati kontinuirani izvor zaraze za pacijente i osoblje u bolnici. U radu je opisano kako sušenje utječe na bakterijsku stanicu, navedeni su mehanizmi pomoću kojih pojedine bakterijske vrste uspješno preživljavaju u suhom okolišu, a objašnjeno je i kako različiti okolišni uvjeti utječu na preživljavanje bakterija u bolničkoj sredini. Navedeni su rezultati ispitivanja osjetljivosti na sušenje nekih češćih bakterijskih uzročnika bolničkih infekcija. Poznavanje čimbenika koji olakšavaju preživljavanja bakterija izloženih sušenju omogućuje izbor učinkovitih mjera dezinfekcije i sterilizacije kojima će se uništiti otporne vrste u zdravstvenim ustanovama, naročito bolnicama.Hand-transmission of microorganisms, mostly bacteria, by the hospital staff is the leading mode of transmission of nosocomial infections. Microorganisms can reach hands through direct contact with the patient but also through contacts with different surfaces in a medical institution. Bacteria that are the most common causes of nosocomial infections can survive for months on a variety of surfaces and materials, and in this way become a continuous source of infection to patients and hospital staff. The paper describes how desiccation affects the bacterial cell, the mechanisms by which bacteria successfully survive in a dry environment and how different environmental conditions affect the survival of bacteria in hospital settings. The sensitivity to desiccation of the most common bacterial causes of nosocomial infections is also described. Knowledge of the factors that facilitate the survival of bacteria exposed to desiccation enables selection of appropriate disinfectant and sterilization method for use in health care facilities

Systemic and Local CC Chemokines Production in a Murine Model of Listeria monocytogenes Infection

Repeated intragastric inoculation of Listeria monocytogenes into BALB/c mice resulted in prolonged bacteraemia and severe hepatic infection. Bacteria could also be isolated from the brain tissue of all experimental mice. During the inflammatory process, chemokine concentrations typically increased at the local site in comparison to the systemic level. The liver-to-serum ratio was more pronounced in the case of macrophage inflammatory protein 1α (MIP-1α), suggesting its role in the inflammatory response in the liver. The ratio of brain-to-serum concentration of monocyte chemoattractant protein 1 (MCP-1) remained the same as in the control animals, while it was lower in the infected mice, both in the case MIP-1α and in the case of regulated on activation, normal T cell expressed and secreted (RANTES). This is in correlation with slight inflammatory infiltrates found in the brain tissue early in infection

Medicinal herbs and herbal preparations for the treatment of urinary infections

Zbog sve veće rezistencije bakterija na poznate antibiotike, u novije vrijeme provodi se niz istraživanja s ciljem pronalaženja prirodnih tvari, posebice biljaka, koje bi mogle pomoći u prevenciji i liječenju urinarnih infekcija koje se tretiraju antibioticima. Urinarne infekcije su upalne bolesti kojima su podložne sve dobne skupine i čine druge najčešće bakterijske infekcije kod ljudi. Češće se javljaju u žena i uglavnom ih uzrokuju gram negativne bakterije. Najčešći uzročnik je Escherichia coli. Uz liječenje antibioticima, često se koriste i pripravci ljekovitog bilja. Cilj rada je dati pregled istraživanja učinkovitosti zimzelene medvjetke, obične planike i brusnice u liječenju urinarnih infekcija.Due to the increasing resistance of bacteria to antibiotics, a number of studies have been conducted to find natural substances, especially plants, which could help prevent and treat urinary tract infections. Urinary infections are inflammatory diseases that are susceptible to all age groups and are the second most common bacterial infections in humans. They are more likely to occur in women and are generally caused by gram negative bacteria. The most common cause is Escherichia coli. With the treatment of antibiotics, medicinal herbs are often used. The aim of the paper is to give an overview of the study of the efficacy of bearberry tree, the strawberry tree and cranberries in the treatment of urinary infections

Überleben von Legionellen im Meerwasser

Legionele se primarno nalaze u vodenim sredinama, najčešće umjetno stvorenim, kao što su sustavi s toplom vodom, jacuzziji, rekreacijski bazeni, klima uređaji i slično. Dobro je poznata činjenica da legionele preživljavaju u slatkovodnim sustavima, no preživljavanje uz visoke koncentracije soli nije detaljno ispitano. U ovoj studiji in vitro pokusima ispitano je preživljavanje Legionella u uzorcima morske vode, vodovodne vode te klorirane vode iz morskog bazena. Korištena su dva soja bakterije, Legionella pneumophila ATCC BAA-74 kao klinički izolat i Legionella pneumophila ST82 koja je izolirana iz morskog bazena. U sirovoj morskoj vodi, kao i u vodovodnoj vodi obje vrste bakterije preživljavaju više od 30 dana. U filtriranoj morskoj vodi L. pneumophila soj ST82 preživljava preko 30 dana, dok L. pneumophila ATCC BAA-74 ugiba unutar 25 dana. Važan faktor u preživljavanju oba soja je i razrjeđenje klorirane morske vode s nekloriranom vodovodnom vodom. Rezultati ukazuju da je neophodna konstantna kontrola i pridržavanje protokola održavanja voda u hotelskim sustavima, te je neophodno uvođenje dodatnih protokola za bazene s morskom vodom. Jedino adekvatnim procesima higijene i monitoringa možemo dovesti do značajnijeg smanjenja rizika od pojave legionarske bolesti i njenog širenja.Legionellae primarily appear in water environments, mostly artificially created, such as warm water systems, Jacuzzis, recreation pools, air conditioning systems, etc. It is well known that legionellae survive in freshwater systems; however, their survival in water with high salt concentrations has not been researched in detail. In vitro tests in this study examined the survival of Legionella in samples of seawater, potable water and chlorinated water from a saltwater pool. We used two bacterial strains - Legionella pneumophila ATCC BAA-74 as the clinical isolate and Legionella pneumophila ST82 isolated from the saltwater pool. Both bacteria survive over 30 days in raw seawater and potable water. In filtered seawater, L. pneumophila strain ST82 survives over 30 days, whereas L. pneumophila ATCC BAA-74 dies within 25 days. An important factor for the survival of both strains is a dilution of chlorinated seawater with non-chlorinated potable water. Our results indicate that a constant control and adherence to water managing protocols are essential in hotel systems, and that additional protocols for saltwater pools are necessary. Only adequate hygiene and monitoring processes can lead to a significant risk reduction of the occurrence and spread of Legionnaires’ disease.Legionellen kommen vor allem in künstlichen Wasserumgebungen vor, z.B. in Warmwasseranlagen, Jacuzzis, Schwimmbäder, Klimaanlagen u ä. Es ist auch gut bekannt, dass Legionellen in Süßwassersystemen vorkommen; ihr Überleben in der Umgebung mit hohen Salzkonzentrationen ist allerdings bisher nicht näher untersucht worden. In dieser Studie wurde anhand von In-vitro-Untersuchungen das Überleben von Legionellen in Proben von Meerwasser, Leitungswasser und gechlortem Wasser aus dem Meerschwimmbad geprüft. Zwei Bakterienstämme wurden verwendet, Legionella pneumophila ATCC BAA-74 als klinisches Isolat und Legionella pneumophila ST82, der aus dem Meerschwimmbadwasser isoliert wurde. In unbehandeltem Meerwasser sowie im Leitungswasser überleben die beiden Bakterienarten über 30 Tage. Im filtrierten Meerwasser überlebt L. pneumophila ST82 (Serotyp 1) über 30 Tage, während L. pneumophila ATCC BAA-74 innerhalb 25 Tage abstirbt. Ein wichtiger Überlebensfaktor bei beiden Bakterienstämmen ist die Verdünnung des Meerwassers mit nicht gechlortem Leitungswassers. Die Ergebnisse zeigen, dass eine ständige Kontrolle und Durchführung des Protokolls für Wasserqualität in Hotels notwendig sind, und dass zusätzliche Protokolle für Meerwasserschwimmbäder eingeführt werden sollen. Nur mit der Durchführung entsprechender Hygienemaßnahmen und Überwachungsprozesse lässt sich das Risiko einer Legionellose verringern

Intracellular life of Francisella and Legionella within amoebae cells

Slobodno-živuće amebe prisutne su u prirodi, a hrane se uglavnom bakterijama, gljivama i algama. Neki mikroorganizmi razvili su različite mehanizme kojima izbjegavaju razgradnju unutar stanica ameba te se nazivaju „ameba-otporni mikroorganizmi”. Bakterije koje pripadaju toj skupini uključuju Cryptococcus neoformans, Chlamydophila pneumoniae, Mycobacterium avium, Listeria monocytogenes, Pseudomonas aeruginosa, Legionella spp. i Francisella tularensis. Francisella i Legionella su gram negativne fakultativno unutarstanične bakterije. Iako dovode do potpuno drugačijih oblika bolesti, te bakterije pokazuju sličan životni ciklus unutar stanica ameba.free-living amoebae are present in the nature, feeding mainly with bacteria, fungi, and algae. Some microorganisms have evolved different mechanisms to resist the digestion by amoebae and they are called “amoeba-resistant microorganisms”. Some of the important human bacterial pathogens belong to this category including Cryptococcus neoformans, Chlamydophila pneumoniae, Mycobacterium avium, Listeria monocytogenes, Pseudomonas aeruginosa, Legionella spp., and Francisella tularensis. Francisella and Legionella are gram negative facultative intracellular bacteria. Although the diseases they cause are completely different, they share some of the unique features in intracellular lifestyle within amoeba cells

Unutarstanični život bakterija Francisella i Legionella u amebama

free-living amoebae are present in the nature, feeding mainly with bacteria, fungi, and algae. Some microorganisms have evolved different mechanisms to resist the digestion by amoebae and they are called “amoeba-resistant microorganisms”. Some of the important human bacterial pathogens belong to this category including Cryptococcus neoformans, Chlamydophila pneumoniae, Mycobacterium avium, Listeria monocytogenes, Pseudomonas aeruginosa, Legionella spp., and Francisella tularensis. Francisella and Legionella are gram negative facultative intracellular bacteria. Although the diseases they cause are completely different, they share some of the unique features in intracellular lifestyle within amoeba cells.Slobodno-živuće amebe prisutne su u prirodi, a hrane se uglavnom bakterijama, gljivama i algama. Neki mikroorganizmi razvili su različite mehanizme kojima izbjegavaju razgradnju unutar stanica ameba te se nazivaju „ameba-otporni mikroorganizmi”. Bakterije koje pripadaju toj skupini uključuju Cryptococcus neoformans, Chlamydophila pneumoniae, Mycobacterium avium, Listeria monocytogenes, Pseudomonas aeruginosa, Legionella spp. i Francisella tularensis. Francisella i Legionella su gram negativne fakultativno unutarstanične bakterije. Iako dovode do potpuno drugačijih oblika bolesti, te bakterije pokazuju sličan životni ciklus unutar stanica ameba

Fotodinamički učinak porfirina na legionele

Legionella pneumophila is a gram-negative bacterium whose natural habitat is water, including rivers, lakes and streams. L. pneumophila is the cause of Pontiac fever and Legionnaires’ disease. Contaminated water distribution systems and air humidifiers are just some of the infection sources. Despite the implementation of antiepidemic measures, the occurrence of Legionnaires’ disease is increasingly frequent, thus requiring a development of new methods for removing legionella from water. One of the approaches is antimicrobial photodynamic therapy, which involves the joint action of photosensitizer, molecular oxygen and visible light of a certain wavelength to produce singlet oxygen and reactive oxygen species that kill the microbial cell. In this paper, minimum inhibitory and minimum bactericidal concentrations of different porphyrins on L. pneumophila were determined with broth dilution method. We used red light in the total dose of 24 J cm-2, while the illumination lasted 10 minutes. The strongest antibacterial effect was established for amphipathic porphyrin. Further studies on the efficiency of these compounds and the use of photodynamic therapy in the inactivation of Legionella in water are required.Legionella pneumophila je gram-negativna bakterija čije je prirodno stanište voda, uključujući rijeke, jezera i potoke. L. pneumophila je uzročnik pontiačke groznice i legionarske bolesti, a kontaminirani distribucijski sustavi za vodu i ovlaživači zraka samo su neki od izvora infekcije. Unatoč provođenju protuepidemijskih mjera, sve je češća pojava legioneloza, stoga je potrebno razviti nove metode za uklanjanje legionele iz vode. Jedan od pristupa je protumikrobna fotodinamička terapija koja uključuje zajedničko djelovanje fotosenzibilizatora, molekularnog kisika i vidljivog svjetla određene valne duljine u svrhu produkcije singletnog kisika i kisikovih reaktivnih vrsta koji ubijaju mikrobnu stanicu. U ovom su radu određivane minimalne inhibitorne i minimalne baktericidne koncentracije različitih porfirina na L. pneumophila u bujonu dilucijskom metodom. Korišteno je crveno svjetlo ukupne doze 24 J cm-2, a osvjetljavanje je trajalo 10 minuta. Najjači antibakterijski učinak utvrđen je kod amfipatskog porfirina i potrebna su daljnja istraživanja o djelotvornosti ovih spojeva i primjene fotodinamičke terapije u inaktivaciji legionele u vodi

The survival of Legionella in rainwater

Legionella is an environmental bacteria and a significant worldwide public health problem. These bacteria can survive a long period of time in distilled water, and more than a year in tap water. Due to these characteristics we were interested to explore how long it will survive in rainwater and if heavy bacterial contamination or bacterial microbiota would affect it's survival. Rainwater is a good alternative source of water in households and is used for watering gardens, washing yards and as bathing water. The rainwater from ten different tanks was analyzed and the results showed that in 90 % of samples the number of microorganisms is elevated. Two rainwater samples were chosen according to the amount of microbiota and survival of L. pneumophila and L. longbeachae was monitored. The results showed that both types of Legionella have been able to survive for 30 days in the rainwater samples but haven’t been able to replicate. The rainwater microbiota restricted the survival of both Legionella strains although the effect was more pronounced in a case of L. longbeachae. These results indicate that both Legionella species can survive in the rainwater environment which means the rainwater could represent a reservoir for Legionella