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Authors: R.E. Lenski and G. J. Velicer

. E. (2000): Developmental cheating in the social bacterium Myxococcus xanthus Nature 404 :598-601. Developmental cheating in the social bacterium Myxococcus xanthus Nature

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137 141 Dudeja S.S.— Kamlesh K.: 2000. Plant growth regulators and nodulation in legume-root nodule bacterium symbiosis — Advances in Plant Physiology vol. 3 179–190 pp

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44 Kristek S. — Kristek A.: 2005. Inoculation of sugar beet seed by the bacterium P. fluorescens — chemical fungicides alternative — Listy Cukrovarnicke a Reparske, vol. 122 no. 2 49

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A szennyvíziszappal kezelt talajok minőségének meghatározásához elengedhetetlen a biológiai mutatók jellemzése. Jelen tanulmány célja az volt, hogy modellkísérlet segítségével megvizsgáljuk a talajokhoz (barna erdőtalaj és réti csernozjom) különböző arányban (0, 20, 40, 60 és 100% iszap:talaj) hozzáadott szennyvíziszap hatását a talaj pH-értékére, nedvességtartalmára és légzésére, valamint termőképességére (növényi szárazanyag-tartalom), enzimatikus tulajdonságaira és az ott élő mikrobiális közösségekre.Modellkísérletben, eltérő arányú iszap/talaj keveréken termesztettünk lucernát 63 napon keresztül. Mértük a relatív növényi szárazanyag-tartalmat, valamint a talaj pH-értékének és nedvességtartalmának a változását. Megvizsgáltuk továbbá a rizoszféra mikrobiális összetételét (aerob heterotróf baktériumok, aerob heterotróf spórások, cellulózbontók és foszfátoldók, fuorescens Pseudomonas ok, Sinorhizo-biummeliloti , aktinomicéták, fonalas gombák, valamint élesztők csíraszámát) és a különböző enzimek (FDA, dehidrogenáz, kataláz, ureáz, proteáz, foszfatáz, β-glükozidáz és aril-szulfatáz) aktivitását. Ugyancsak meghatároztuk a kibocsátott CO 2 alapján a talajlégzés mértékét.Eredményeink azt mutatják, hogy a szennyvíziszap hozzáadásával a talaj hosszabb ideig megőrizte nedvességtartalmát, mint a kontroll (100% talaj/0% iszap), valamint emelkedett a talaj pH-értéke is. A növények egészséges fejlődésén és növekedésén kívül, a legnagyobb növényi szárazanyag-tömeget is a nagy szennyvíziszap tartalmú minták (60–100% iszap) esetében mértük. A minták szennyvíziszap- koncentrációjának emelésével jelentősen nőtt a tenyészthető mikrobiális populációk sűrűsége is a lucerna rizoszférájában.A leggyakrabban előforduló baktériumok a következő genus okhoz tartoztak: Acinetobacter, Azotobacter, Bacillus, Brevundimonas, Cellulomonas, Chromo-bacterium, Corynebacterium, Enterobacter, Escherichia, Flavobacterium, Klebsiella, Micrococcus, Proteus, Pseudomonas, Sinorhizobium, Serratia, Stenotrophomonas, Streptococcus, Streptomyces és Zooglea . A legmagasabb fonalasgomba-populációkat a barna erdőtalajban mértük, mindkét (hódmezővásárhelyi és nyíregyházi) szennyvíziszap jelenlétében. A leggyakoribb izolátumok az Altenaria, Aspergillus, Cephalosporium, Cladosporium, Fusarium, Geotrichum, Mucor, Penicillium, Rhizopus és _s

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Sunscreen products are meant to protect people from damaging UVA and UVB radiation. However, in some formulations the UV filters they contain can react and form many photodegradation products. Their potential toxicity has not yet been investigated. In this study effect-specific analysis has been used to evaluate the bioactivity of photodegradation products in sunscreens. HPTLC-bioluminescence coupling with the luminescent bacterium Vibrio fischeri was used. Problems in method development were because of the sensitivity of the bacteria and the wettability of HPTLC plates. A separation system using HPTLC LiChrospher plates and automated multiple development (AMD) with tert -butyl methyl ether- n -hexane was chosen. Detection was by UV in addition to Vibrio fischeri . First, biodetection was performed on pure standard solutions of the UV filters. UV filters with molecular weight >400 had no bioactivity; these included all newer UV filters (not in use before 1998). Five commercially available sunscreens with different UV filter combinations were then analyzed. They were irradiated on microscope slides with artificial light and natural sunlight and on the skin with natural sunlight. For extraction, a mixture of ethanol and acetone was used. The bioactivity which can be indicative of (cyto)toxic effects of the photodegradation products was higher than that of the corresponding UV filter. In comparison of HPLC-DAD and LC-MS with detection with Vibrio fischeri , a high signal in chemical-physical detection did not always correspond to high bioactivity, and vice versa. It was shown that biodetection with Vibrio fischeri was a suitable method for examination of photodegradation products in sunscreens, making this bioassay a useful addition to conventional analytical methods.

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Acta Microbiologica et Immunologica Hungarica
Authors: Hossein Sarmadian, Razieh Nazari, Mohammad Zolfaghari, Mina Pirayandeh, Maryam Sadrnia, Mohammad Arjomandzadegan, Leonid Titov, Fariba Rajabi, Azam Ahmadi and Mana Shojapoor

Mycobacterium tuberculosis growth rate is closely coupled to rRNA transcription which is regulated through carD gene. The aim of this study was to determine the sequence of carD gene in drug susceptible and resistant clinical isolates of M. tuberculosis and designing of a PCR assay based on carD sequence for rapid detection of this bacterium.Specific primers for amplification of carD gene were carefully designed, so that whole sequence of gene could be amplified; therefore primers were positioned at the upstream (promoter of this gene and ispD gene) and downstream (in ispD gene). DNA from 41 clinical isolates of M. tuberculosis with different pattern of drug resistance was used in the study. PCR conditions and annealing temperature were designed by means of online programs. PCR products were sequenced by ABI system.PCR product of carD gene was a 524 bp fragment. This method could detect all resistant and susceptible strains of M. tuberculosis. The size of amplified fragment was similar in all investigated samples. Sequence analysis showed that there was similar sequence in all of our isolates therefore probably this gene is considered to be conservative. Translation of nucleotide mode to amino acids was showed that TRCF domain in N-terminal of protein CarD was found to be fully conservative.This is the first study on the sequence of carD gene in clinical isolates of M. tuberculosis. This conservative gene is recommended for use as a target for designing of suitable inhibitors as anti-tuberculosis drug because its importance for life of MTB. In the other hand, a PCR detection method based on detection of carD gene was recommended for rapid detection in routine test.

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Identification of Mycobacterium tuberculosis and M. bovis is necessary for the application of adequate drug therapy. PCR amplification is a good tool for this purpose, but choosing proper target is of a great concern. We describe a PCR assay for fast detection of M. tuberculosis and M. bovis.As a BLAST and BLASTP search we selected regulatory gene whiB7 that encodes multi-drug resistance in this bacterium. Thirty clinical isolates of M. tuberculosis were sequenced and all the mutations in gene whiB7 were detected. The best set of several pairs of primers was selected and used in comparison by rpoB gene for differentiation of M. bovis, M. avium, M. kansasii, M. phlei, M. fortuitum, M. terrae, seven non-pathogenic Mycobacterium isolates and 30 clinical isolates of M. tuberculosis.It was proved that only clinical isolates of M. tuberculosis and M. bovis have positive bands of 667 bp whiB7. Other non-tuberculous and non-pathogenic isolates did not show any positive sign. Furthermore, 667-bp PCR products of whiB7 gene were observed for ten positive sputum samples (preliminarily approved to be positive for M. tuberculosis by commercially real-time based method), but no bands were detected in 5 negative sputum samples. RpoB gene could not differentiate non-tuberculous strains and non-pathogenic isolates from pathogenic clinical isolates. We concluded that PCR amplification of the gene coding for the WhiB7 protein could be successfully used as a good tool for rapid identification of M. tuberculosis and M. bovis. We propose application of this method as a rapid and simple approach in mycobacteriological laboratories.

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Absztrakt:

A Borrelia miyamotoi-t 1995-ben fedezték fel. Ez egy, emberben visszatérő lázat (relapsing fever, febris recurrens) okozó baktérium, amelyet az Ixodes ricinus fajcsoportba tartozó kullancsok terjesztenek. Ez a kórokozó genetikailag, járványtanilag és az általa okozott kórkép tekintetében is különbözik a szintén kullancsok által terjesztett Borrelia burgdorferi sensu lato (Lyme spirochaeta) baktériumoktól. Eddig világszerte több mint 50 heveny lázas megbetegedésben szenvedő páciensből mutatták már ki, ezenfelül három tumoros betegben meningoencephalitist okozott ez a kórokozó. A különböző élőhelyeken található kullancsok és gazdáik fertőzöttségének mértéke, eloszlása és a fertőzés mechanizmusa nem tisztázott még. A B. miyamotoi elsősorban lázat okoz, ami miatt más, kullancsok által terjesztett fertőzésekkel is összetéveszthető. Az utóbbi évek intenzív vizsgálatai alapján nemcsak egyre több földrajzi régióból mutatják ki ezt a baktériumot kullancsokból, de folyamatosan növekszik a publikált humán esetszám is, ezért növekvő jelentőségű (emerging) kórokozóként tartják számon. Irodalmi áttekintésünkben összegezzük az eddigi ismereteinket a Borrelia miyamotoi-val kapcsolatban. Orv Hetil. 2017; 158(29): 1124–1130.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: N. Tsibakhashvili, L. Mosulishvili, E. Kirkesali, I. Murusidze, M. Frontasyeva, S. Pavlov, I. Zinicovscaia, P. Bode and Th. van Meerten

Abstract  

Instrumental neutron activation analysis was used to study accumulation of Hg(II) and Cr(VI) ions in Arthrobacter globiformis 151B, a gram-positive, Cr(VI)-reducer aerobic bacterium isolated from basalt sample taken from the most polluted region in the Republic of Georgia (Kazreti). Experiments were focused on (1) accumulation of Hg(II) in bacterial cells; (2) accumulation of Cr(VI) in A. globiformis 151B in the presence of Hg(II) and (3) effects of Hg(II) and mixture of Cr(VI)–Hg(II) on the elemental composition of bacteria. It was shown that this bacterial strain possesses uptake mechanisms by which mercury toxicity can be reduced in environment and that accumulation of Cr(VI) in A. globiformis 151B is much higher in the presence of Hg(II) ions. Accumulation of Hg(II), similar to the Cr(VI) accumulation, follows well the Lengmuir–Freundlich model. NAA measurements showed increased content of Fe in bacteria under Hg and Cr action, suggesting that Fe-containing biomolecules play a decisive role in detoxifying of heavy metals by A. globiformis 151B. A concentration of 5000 μg/L of Hg(II) was found to be critical for A. globiformis 151B. At this concentration of Hg(II) the concentrations of both essential (Na, Mg, Al, Cl, K, Mn, Zn) and some non-essential elements (Rb, Sb, Sc, As) changed drastically along with a decrease of the biomass of bacteria by a factor of two. One may assume that under this high exposure to Hg(II) the structure of the bacterial cell wall was destroyed.

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Abstract

Gingipains, a group of arginine or lysine specific cysteine proteinases (also known as RgpA, RgpB and Kgp), have been recognized as major virulence factors in Porphyromonas gingivalis. This bacterium is one of a handful of pathogens that cause chronic periodontitis. Gingipains are involved in adherence to and colonization of epithelial cells, hemagglutination and hemolysis of erythrocytes, disruption and manipulation of the inflammatory response, and the degradation of host proteins and tissues. RgpA and Kgp are multi-domain proteins composed of catalytic domains and hemagglutinin/adhesin (HA) regions. The structure of the HA regions have previously been defined by a gingipain domain structure hypothesis which is a set of putative domain boundaries derived from the sequences of fragments of these proteins extracted from the cell surface. However, multiple sequence alignments and hidden Markov models predict an alternative domain architecture for the HA regions of gingipains. In this alternate model, two or three repeats of the socalled “cleaved adhesion” domains (and one other undefined domain in some strains) are the modules which constitute the substructure of the HA regions. Recombinant forms of these putative cleaved adhesin domains are indeed stable folded protein modules and recently determined crystal structures support the hypothesis of a modular organisation of the HA region. Based on the observed K2 and K3 structures as well as multiple sequence alignments, it is proposed that all the cleaved adhesin domains in gingipains will share the same β-sandwich jelly roll fold. The new domain model of the structure for gingipains and the Hag proteins of P. gingivalis will guide future functional studies of these virulence factors.

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