Bacteriophage therapy against plant, animal and human pathogens

Bacteriophages are specific infective agents of various bacteria. They can be divided into various groups according to their life cycle. The lytic phages kill their host cells and this property can be applied for selective elimination of pathogenic bacteria. The first bacteriophage treatment was described one hundred years ago, and phage therapy had been extensively used till the Second World War. Upon appearance of antibiotics, the medical application of phages retrograded in most parts of the world. In the last decades, owing to the costs of development of new antibiotics and rapid emergence of multidrug-resistant bacteria, this old approach was revitalized and phage-based treatment was legalized from the middle of the last decade. Here, we summarize the current knowledge on phage therapy, its advantages and potential drawbacks. The application of phages against plant pathogens, especially Erwinia amylovora is discussed. Moreover, the current status of phage therapy against food-borne, animal and human pathogens is also presented. Among these, special focus is set on phages of Staphylococcus aureus, Salmonella typhimurium and Listeria monocytogenes. Phage cocktails against L. monocytogenes and E. amylovora have been already commercialized

Quinone binding site in a type VI sulfide:quinone oxidoreductase

Monotopic membrane-bound flavoproteins, sulfide:quinone oxidoreductases (SQRs), have a variety of physiological functions, including sulfide detoxification. SQR enzymes are classified into six groups. SQRs use the flavin adenine dinucleotide (FAD) cofactor to transfer electrons from sulfide to quinone. A type VI SQR of the photosynthetic purple sulfur bacterium, Thiocapsa roseopersicina (TrSqrF), has been previously characterized, and the mechanism of sulfide oxidation has been proposed. This paper reports the characterization of quinone binding site (QBS) of TrSqrF composed of conserved aromatic and apolar amino acids. Val331, Ile333, and Phe366 were identified near the benzoquinone ring of enzyme-bound decylubiquinone (dUQ) using the TrSqrF homology model. In silico analysis revealed that Val331 and Ile333 alternately connected with the quinone head group via hydrogen bonds, and Phe366 and Trp369 bound the quinones via hydrophobic interactions. TrSqrF variants containing alanine (V331A, I333A, F366A) and aromatic amino acid (V331F, I333F, F366Y), as well as a C-terminal alpha-helix deletion (CTD) mutant were generated. These amino acids are critical for quinone binding and, thus, catalysis. Spectroscopic analyses proved that all mutants contained FAD. I333F replacement resulted in the lack of the charge transfer complex. In summary, the interactions described above maintain the quinone molecule's head in an optimal position for direct electron transfer from FAD. Surprisingly, the CTD mutant retained a relatively high level of specific activity while remaining membrane-anchored. This is a unique study because it focuses on the QBS and the oxidative stage of a type VI sulfide-dependent quinone reduction

Determination of endogenous methane formation by photoacoustic spectroscopy

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Improvement of Biogas Production by Bioaugmentation

Biogas production technologies commonly involve the use of natural anaerobic consortia of microbes. The objective of this study was to elucidate the importance of hydrogen in this complex microbial food chain. Novel laboratory biogas reactor prototypes were designed and constructed. The fates of pure hydrogen-producing cultures of Caldicellulosiruptor saccharolyticus and Enterobacter cloacae were followed in time in thermophilic and mesophilic natural biogas-producing communities, respectively. Molecular biological techniques were applied to study the altered ecosystems. A systematic study in 5-litre CSTR digesters revealed that a key fermentation parameter in the maintenance of an altered population balance is the loading rate of total organic solids. Intensification of the biogas production was observed and the results corroborate that the enhanced biogas productivity is associated with the increased abundance of the hydrogen producers. Fermentation parameters did not indicate signs of failure in the biogas production process. Rational construction of more efficient and sustainable biogas-producing microbial consortia is proposed

VÉR-AGY GÁT TRANSZPORTEREK ÉS GYÓGYSZERBEJUTTATÁS A KÖZPONTI IDEGRENDSZERBE

A vér-agy gát anatómiai alapját képező agyi endotélsejtek genomjának 11 %-át transzporterek génjei teszik ki, ami jól jelzi a szállítófehérjék fontosságát. Az agyi hajszálerekben az Slc (solute carrier) szállítófehérje család látja el a központi idegrendszert tápanyagokkal, vitaminokkal, nyomelemekkel, metabolikus prekurzorokkal. Ezek a karrierek főképpen az agyba irányuló transzportban vesznek részt, míg a vér-agy gát efflux transzporterei a neurotranszmitterek és metabolitok szintjét szabályozzák az agyban, valamint megakadályozzák a potenciálisan toxikus anyagok, xenobiotikumok bejutását a vérből az agyba. Az efflux transzportereknek köszönhető a legtöbb központi idegrendszeri gyógyszerjelölt molekula alacsony átjutása is a vér-agy gáton. A probléma megoldására jelentős erővel folynak olyan kutatások, amelyek a hatóanyagokat a vér-agy gát szállítófehérjéinek segítségével juttatják be a központi idegrendszerbe. Megvizsgáltuk a gyógyszerek transzportja és célzott bevitele szempontjából kulcsfontosságú Slc és efflux pumpa fehérjecsaládok génexpressziós mintázatát izolált patkány agyi mikroerekben. A glükóz transzporterek közül a Glut-1 expessziós mRNS szintje volt a legmagasabb, de a Glut-3 és -5 is kifejeződött. A minden vizsgált aminosav transzporter esetében magas génexpressziós szintet mértünk, a legmagasabb a gyógyszerek bejutásában is szerepet játszó Lat-1, valamint a Cat-1 és SN-1 szintje volt. A peptid transzporterek esetében a Pht-2 szintje szignifikánsan magasnak bizonyult, míg a Pept-1, -2 génexpressziója nem volt mérhető. A kreatint (Crt), taurint (Taut) és C-vitamint (Asct-1) szállító fehérjék is expresszálódtak agyi mikroerekben. Az efflux pumpák esetében az ABC transzporter P-glikoprotein (Abcb1), a mellrák rezisztencia fehérje (BCRP, Abcg2), és a multidrog rezisztencia proteinek közül az Mrp-1, 4, 5 mRNS szinje volt a legmagasabb, míg az Mrp-2 nem volt mérhető. A legtöbb vizsgált vér-agy gát transzporter mRNS expressziójára jó egyezést kaptunk izolált agyi mikroerek és a vér-agy gát tenyészetes modellje között. Mivel az Slc transzporterek jelentős mértékben és egyedi mintázatban expresszálódnak a vér-agy gáton, Slc transzportfehérjék ligandjainak kombinációjával ellátott nanorészecskék felvételét teszteltük agyi endotélsejteken, és megállapítottuk, hogy a nanorészecskék felszínére kötött ligandok szignifikánsan magasabb bejutást eredményeznek, mint a jelöletlen partikulumok

Identification of unknown filamentous fungi from willow wood and sorghum chips

Molecular biological methods are generally applied in the identification processes of microorganisms. We aimed to isolate numerous cellulolytic filamentous fungi strains from willow wood and sorghum chips, and attempted to identify them with polymerase chain reaction (PCR). Modified Czapek-Dox medium was used with the addition of microcrystalline cellulose and carboxymethyl cellulose (CMC) as a source of carbon, in order to isolate cellulolytic filamentous fungi strains. Through sequence-based identification, representatives of the genera Trichoderma, Aspergillus and Fusarium were identified

Biosurfactant synthesis in the oil eater rhodococcus erythropolis MK1 strain

Oil pollution is a very serious problem in the world. There were numerous oil spills in the last three decades and had great impact on the environment. They caused damages in wildlife as well as in economy by cutting down the agriculture, fishing, and tourism. Surfactants are useful weapons in the war against oil pollution. They are suitable to clean oil tanks and pipes and they are useful to solublize animal fats in food industrial wastewater. Many bacteria can produce substantial amount of biosurfactants which can emulsify hydrophobic hydrocarbons, so that the native microflora can utilize the pollutants. An additional advantage of the biosurfactants over the synthetic surface active molecules is that these compounds are easily biodegradable. A special biosurfactant group is composed of mycolic acids which are basically a-alkyl, (3-hydroxy fatty acids. Mycolic acids are the most characteristic components of the cell wall of the so called mycolata bacterial group. This group belongs to the Actinomycetales and contains the genera Mycobacterium, Corynebacterium, Nocardia, Rhodococcus and others. We aimed to map the mycolic acid biosynthesis pathway in Rhodococcus erythropolis MK1 strain isolated by us from polluted soil. In first step, we sequenced the genome of our strain by SOLID™ next generation DNA sequencer. The reads were mapped on the R. erythropolis PR4 genome in the NCBI database. We searched for rhodococcal homologs of the known mycobacterial and corynebacterial genes involved in mycolic acid biosynthesis. We found conserved regions in the genome which are likely responsible for the biosynthesis of mycolic acids. The ongoing comparative whole genome transcript analysis will reveal the genes really necessary for the anabolism of mycolic acids