Wyniki wyszukiwania - Biblioteka Nauki

1

Osmoregulation - dependent expression of Yersinia enterocolitica virulence factors

100%

Brzostek K. , Stencel I. , Hrebenda J.

Acta Microbiologica Polonica

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1999

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tom 48

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nr 1

2

Evaluation of peripheral blood leukocyte subpopulations by flow cytometry in calves treated with Mannheimia haemolytica leukotoxin

86%

Bednarek D. , Urban-Chmiel R. , Dudek K. , Szymanska-Czerwinska M.

Bulletin of the Veterinary Institute in Puławy

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2009

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tom 53

|

nr 2

199-203

EN

The aim of the study was to evaluate the effect of Mannheimia haemolytica leukotoxin (Lkt) on cellular immune response in clinically-healthy calves given intravenously 25 µg per animal of M. haemolytica Al Lkt. The alternations of peripheral blood leukocytes were examined with a flow cytometry. The Lkt treated calves were compared with the non-treated controls before (0) and 1, 2, 3, 4, 5, 6, and 24 h after the treatment. The following parameters were assayed: white blood cell (WBC) count, percentage of polymorphonuclear leukocytes (PMNL), mid-size leukocytes, total percentage of lymphocytes and their subsets: CD2⁺ (T lymphocytes), CD4⁺ (T helper lymphocytes), and CD8⁺ (T suppressor/cytotoxic lymphocytes) with CD4⁺: CD8⁺ratio, and also WC4⁺ cells (B lymphocytes). The obtained results showed that in the treated calves, the WBC count, the percentages of PMNL, mid-size leukocytes, and some subpopulations of peripheral lymphocytes (CD2⁺, CD4⁺, CD8⁺) were significantly lower compared with the controls during the first of three hours of the experiment, and then the parameters increased and returned to the physiological level.

3

Effect of Pseudomonas aeruginosa exotoxin a on PHA-induced lymphocyte proliferation

86%

Michalkiewicz J. , Patzer J. , Dzierzanowska D. , Stachowski J. , Madalinski K.

Archivum Immunologiae et Therapiae Experimentalis

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1989

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tom 37

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nr 3-4

4

Cellular secretory systems involved in Salmonella pathogenesis mechanism

86%

Molenda J.

Advances in Agricultural Sciences

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2002

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tom 08

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nr 1

5

New generation of peptide antibiotics

72%

Dubin A. , Mak P. , Dubin G. , Rzychon M. , Stec-Niemczyk J. , Wladyka B. , Maziarka K. , Chmiel D.

Acta Biochimica Polonica

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2005

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tom 52

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nr 3

633-638

EN

The increasing antibiotic resistance of pathogenic bacteria calls for the development of alternative antimicrobial strategies. Possible approaches include the development of novel, broad-spectrum antibiotics as well as specific targeting of individual bacterial virulence factors. It is impossible to decide currently which strategy will prove more successful in the future since they both promise different advantages, but also introduce diverse problems. Considering both approaches, our laboratory's research focuses on the evaluation of hemocidins, broad-spectrum antibacterial peptides derived from hemoglobin and myoglobin, and staphostatins, specific inhibitors of staphopains - Staphylococcus aureus secreted proteases that are virulence factors regarded as possible targets for therapy. The article summarizes recent advances in both fields of study and presents perspectives for further development and possible applications.

6

Expression of Helicobacter pylori ggt gene in baculovirus expression system and activity analysis of its products

72%

Kong M. , Xu M. , He Y.-L. , Zhang Y.-L.

Polish Journal of Microbiology

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2011

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tom 60

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nr 3

EN

The γ-glutamyltranspeptidase (GGT) of Helicobacter pylori (HpGT) is a newly found virulence factor. In an approach to gain insight into the gene function, the four domains of the HpGT were cloned and expressed in baculovirus expression system. The results of a functional assay showed that the HpGT products acted as GGT, even when the N-terminal 380 amino acids were deleted. However, only the full length open reading frame (ORF) of the HpGT gene was apparently e$ective on cell growth. This result indicated that the products of the full length ORF might have an important role in gastric carcinogenesis. In this paper, we are the first to report that changes of mitochondrial membrane potential can be detected using 5, 5’, 6, 6’-tetrachloro-1, 1’, 3, 3’-tetraethylbenzimidazole carbocyanine iodide (JC-1) staining in insect cells.

7

Communication between microorganisms as a basis for production of virulence factors

72%

Gospodarek E. , Bogiel T. , Zalas-Wiecek P.

Polish Journal of Microbiology

|

2009

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tom 58

|

nr 3

191-198

EN

Quorum sensing (QS), or cell-to-cell communication in bacteria, is achieved through the production and subsequent response to the accumulation of extracellular signal molecules called autoinductors. The main role of QS is regulation of production of virulence factors in bacteria. Bacterial pathogenicity is often manifested by the expression of various cell-associated and secreted virulence factors, such as exoenzymes, toxins and biofilm. In bacteria, the expression of virulence factors is controlled coordinately by the global regulatory QS systems, which includes the AI-1/LuxIR-, AI-2/LuxS-, AI-3/QsC-, AIP/Agr-based systems. The regulation of production of virulence factors is extremely complex and many components influence it.

8

Real-time PCR in microbiological and immunological diagnostics of mastitis caused by Staphylococcus aureus enterotoxic strains

72%

Nawrotek P. , Fijalkowski K. , Czernomysy-Furowicz D. , Silecka A.

Advances in Agricultural Sciences

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2008

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tom 12

9

Characterisation of porcine enteropathogenic Escherichia coli isolated in Northeastern India

72%

Kylla H. , Dutta T. K. , Roychoudhury P. , Subudhi P. K. , Lalhruaipuii , Lalsiamthara J. , Mandakini R.

Journal of Veterinary Research

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2020

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tom 64

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nr 3

10

First report of molecular identification of Cystoisospora suis in piglets with lethal diarrhea in Japan

72%

Matsubayashi M. , Takayama H. , Kusumoto M. , Murata M. , Uchiyama Y. , Kaji M. , Sasai K. , Yamaguchi R. , Shibahara T.

Acta Parasitologica

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2016

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tom 61

|

nr 2

11

Relationship between Vac A toxin and ammonia in Helicobacter pylori-induced apoptosis in human gastric epithelial cells

72%

Chiozzi V. , Mazzini G. , Oldani A. , Sciullo A. , Ventura U. , Romano M. , Boquet P. , Ricci V.

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nr 3

23-30

EN

VacA toxin is one of the most important virulence factors produced by H. pylori even though neither its role nor its action mechanisms are completely understood. First considered as a toxin inducing only cell vacuolation, VacA causes apoptosis of gastric epithelial cells by targeting mitochondria. A hotly debated question about VacA action is its relationship with ammonia, which is produced in vivo by H. pylori urease. While ammonia is strictly required for VacA-dependent vacuolation, its role in VacA-induced apoptosis is much less defined. This study was thus aimed to investigate the relationship between VacA toxin and ammonia in H. pylori-induced mitochondrial damage and apoptosis of human gastric epithelial cells in culture by means of flow cytometry. Our results show that, unlike cell vacuolation, in MKN 28 cells neither apoptosis nor dissipation of mitochondrial transmembrane potential induced by VacA require ammonia. Nevertheless, ammonia significantly potentiates both these VacA-induced effects, but independently of the swelling of VacA-containing endosomes (i.e., vacuolation). Our findings make unlikely the hypothesis that ammonia-dependent swelling and rupture of endosomal vesicles in which VacA is sequestered after cell internalization may allow the toxin to reach mitochondria and trigger apoptosis.

12

Multiple-locus variable number of tandem repeats fingerprinting (MLVF) and virulence factor analysis of methicillin resistant Staphylococcus aureus SCCmec type III

72%

Emaneini M. , Jabalameli L. , Iman-Eini H. , Aligholi M. , Ghasemi A. , Nakhjavani F. A. , Taherikalani M. , Khoramian B. , Asadollahi P. , Jabalameli F.

Polish Journal of Microbiology

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2011

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tom 60

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nr 4

EN

Methicillin resistant Staphylococcus aureus (MRSA), particularly strains with type III staphylococcal cassette chromosome mec (SCCmec), represent a serious human pathogen in Tehran, Iran. The disease-causing capability depends on their ability to produce a wide variety of virulent factors. The prevalence of exotoxin genes and multiple-locus variable number of tandem repeats fingerprinting (MLVF) profile among MRSA isolates, from patients in Tehran, was evaluated by PCR and Multiplex-PCR. The MLVF typing of 144 MRSA isolates with type III SCCmec produced 5 different MLVF types. Generally, 97.2% (140/144) of all the isolates were positive for at least one of the tested exotoxin genes. The most prevalent genes were hld, found in 87.5% (126/144) of the isolates followed by lukE-lukD and hla found in 72.9% (105/144) and 70.1% (101/144) of the isolates, respectively. The tst gene, belonging to MLVF types I, IV and V, was found among three of the isolates from blood and wound samples. The sea gene was detected in 58.3% (84/144) of the isolates and the sed and see genes were found in one isolate with MLVF type V. The coexistence of genes was observed in the 87.5% (126/144) of the isolates.The rate of coexistence of hld with lukE-lukD, hla with lukE-lukD and sea with lukE-lukD were 66.7% (96/144), 44.4% (64/144) and 44.4% (64/144), respectively. The present study demonstrated that MRSA strains with type III SCCmec show different MLVF patterns and exotoxin profiles.

13

Acinetobacter baumannii: biology and drug resistance — role of carbapenemases

72%

Nowak P. , Paluchowska P.

Folia Histochemica et Cytobiologica

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2016

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tom 54

|

nr 2

14

Evaluation of urease activity by the human Ureaplasma species

72%

Biernat-Sudolska M. , Bilska-Wilkosz A. , Rojek-Zakrzewska D. , Zawilinska B. , Kosz-Vnenchak M.

Folia Biologica

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2017

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tom 65

|

nr 3

15

Trichomonas vaginalis acidic phospholipase A2: isolation and partial amino acid sequence

72%

Escobedo-Guajardo B. L. , Gonzalez-Salazar F. , Palacios-Corona R. , Cruz V. M. T. , Morales-Vallarta M. , Mata-Cardenas B. D. , Garza-Gonzalez J. N. , Rivera-Silva G. , Vargas-Villarreal J.

Acta Parasitologica

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2013

|

tom 58

|

nr 4

EN

Sexually transmitted diseases are a major cause of acute disease worldwide, and trichomoniasis is the most common and curable disease, generating more than 170 million cases annually worldwide. Trichomonas vaginalis is the causal agent of trichomoniasis and has the ability to destroy in vitro cell monolayers of the vaginal mucosa, where the phospholipases A2 (PLA2) have been reported as potential virulence factors. These enzymes have been partially characterized from the subcellular fraction S30 of pathogenic T. vaginalis strains. The main objective of this study was to purify a phospholipase A2 from T. vaginalis, make a partial characterization, obtain a partial amino acid sequence, and determine its enzymatic participation as hemolytic factor causing lysis of erythrocytes. Trichomonas S30, RF30 and UFF30 sub-fractions from GT-15 strain have the capacity to hydrolyze [2-14C-PA]-PC at pH 6.0. Proteins from the UFF30 sub-fraction were separated by affinity chromatography into two eluted fractions with detectable PLA A2 activity. The EDTA-eluted fraction was analyzed by HPLC using on-line HPLC-tandem mass spectrometry and two protein peaks were observed at 8.2 and 13 kDa. Peptide sequences were identified from the proteins present in the eluted EDTA UFF30 fraction; bioinformatic analysis using Protein Link Global Server charged with T. vaginalis protein database suggests that eluted peptides correspond a putative ubiquitin protein in the 8.2 kDa fraction and a phospholipase preserved in the 13 kDa fraction. The EDTA-eluted fraction hydrolyzed [2-14C-PA]-PC lyses erythrocytes from Sprague-Dawley in a time and dose-dependent manner. The acidic hemolytic activity decreased by 84% with the addition of 100 μM of Rosenthal’s inhibitor.

16

Antibiotic resistance genes and virulence factors in Enterococcus faecium and Enterococcus faecalis from diseased farm animals: pigs, cattle and poultry

72%

Seputiene V. , Bogdaite A. , Ruzauskas M. , Suziedeliene E.

Polish Journal of Veterinary Sciences

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2012

|

tom 15

|

nr 3

EN

Eighty enterococcal isolates (E. faecium, n=38, E. faecalis, n=42) from diseased farm animals (swine, cattle, poultry) in Lithuania have been studied for the prevalence of antibiotic resistance and for resistance and virulence genetic determinants. 86% of E. faecium and 71% of E. faecalis isolates were multidrug resistant (resistant to three or more unrelated antibiotics). Resistance to aminoglycosides, tetracycline and erythromycin was found most frequently in both species (61%, 69%) and was linked to aph(3’)-IIIa, aac(6’)-Ie-aph(2”)-Ia, ant(6)-Ia (aminoglycoside resistance), tetM, tetL (tetracycline resistance), ermA, ermB (erythromycin resistance) gene combinations, which were supplemented with chloramphenicol resistance genes catA7, catA8 (E. faecalis) and catA9 (E. faecium). All E. faecalis isolates harboured genes coding for virulence factors agg, esp, fsr gelE alone or in combinations with the high prevalence of esp gene in isolates from cattle (63%) and pigs (79%). The origin- dependent incidence of agg gene variants prgB and asp1 was observed. The results indicate the existence of a large pool of potentially virulent and multidrug resistant E. faecalis in diseased farm animals posing risk to humans.

17

Effects of allicin on the formation of Pseudomonas aeruginosa biofilm and the production of quorum-sensing controlled virulence factors

72%

Lihua L. , Jianhui W. , Jialin Y. , Yayin L. , Guanxin L.

Polish Journal of Microbiology

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2013

|

tom 62

|

nr 3

EN

The Gram-negative Pseudomonas aeruginosa bacterial pathogen is reputed for its resistance to multiple antibiotics, and this property is strongly associated with the development of biofilms. Bacterial biofilms form by aggregation of microorganisms on a solid surface and secretion of an extracellular polysaccharide substances that acts as a physical protection barrier for the encased bacteria. In addition, the P. aeruginosa quorum-sensing system contributes to antibiotic resistance by regulating the expression of several virulence factors, including exotoxin A, elastase, pyoverdin and rhamnolipid. The organosulfur compound allicin, derived from garlic, has been shown to inhibit both surface-adherence of bacteria and production of virulence factors. In this study, the effects of allicin on P. aeruginosa biofilm formation and the production of quorum-sensing controlled virulence factors were investigated. The results demonstrated that allicin could inhibit early bacterial adhesion, reduce EPS secretion, and down-regulate virulence factors’ production. Collectively, these findings suggest the potential of allicin as a therapeutic agent for controlling P. aeruginosa biofilm.

18

Aktywność celulolityczna a wirulencja Clavibacter michiganensis subs. sepedonicus

72%

Pastuszewska T. , Gryn G.

Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin

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2013

|

nr 270

19

The virulence factors of Bordetella pertussis: talented modulators of host immune response

72%

Fedele G. , Bianco M. , Ausiello C. M.

Archivum Immunologiae et Therapiae Experimentalis

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2013

|

tom 61

|

nr 6

20

Fungi pathogenic to humans: molecular bases of virulence of Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus

72%

Karkowska-Kuleta J. , Rapala-Kozik M. , Kozik A.

Acta Biochimica Polonica

|

2009

|

tom 56

|

nr 2

211-224

EN

The frequency of severe systemic fungal diseases has increased in the last few decades. The clinical use of antibacterial drugs, immunosuppressive agents after organ transplantation, cancer chemotherapy, and advances in surgery are associated with increasing risk of fungal infections. Opportunistic pathogens from the genera Candida and Aspergillus as well as pathogenic fungi from the genus Cryptococcus can invade human organism and may lead to mucosal and skin infections or to deep-seated mycoses of almost all inner organs, especially in immunocompromised patients. Nowadays, there are some effective antifungal agents, but, unfortunately, some of the pathogenic species show increasing resistance. The identification of fungal virulence factors and recognition of mechanisms of pathogenesis may lead to development of new efficient antifungal therapies. This review is focused on major virulence factors of the most common fungal pathogens of humans: Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans. The adherence to host cells and tissues, secretion of hydrolytic enzymes, phenotypic switching and morphological dimorphism contribute to C. albicans virulence. The ability to grow at 37°C, capsule synthesis and melanin formation are important virulence factors of C. neoformans. The putative virulence factors of A. fumigatus include production of pigments, adhesion molecules present on the cell surface and secretion of hydrolytic enzymes and toxins.