Wyniki wyszukiwania - Biblioteka Nauki

1

Proteomics in studies of Staphylococcus aureus virulence

100%

Bonar E. , Wójcik I. , Wladyka B.

Acta Biochimica Polonica

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2015

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tom 62

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nr 3

367-381

EN

Staphylococcus aureus is a widespread, opportunistic pathogen that causes community and hospital acquired infections. Its high pathogenicity is driven by multifactorial and complex mechanisms determined by the ability of the bacterium to express a wide variety of virulence factors. The proteome secreted into extracellular milieu is a rich reservoir of such factors which include mainly nonenzymatic toxins and enzymes. Simultaneously, membrane proteins, membrane-cell wall interface proteins and cell wall-associated proteins also strongly influence staphylococcal virulence. Proteomics shows a great potential in exploring the role of the extracellular proteome in cell physiology, including the pathogenic potential of particular strains of staphylococci. In turn, understanding the bacterial physiology including the interconnections of particular factors within the extracellular proteomes is a key to the development of the ever needed, novel antibacterial strategies. Here, we briefly overview the latest applications of gel-based and gel-free proteomic techniques in the identification of the virulence factors within S. aureus secretome and surfacome. Such studies are of utmost importance in understanding the host-pathogen interactions, analysis of the role of staphylococcal regulatory systems and also the detection of posttranslational modifications emerging as important modifiers of the infection process.

2

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

100%

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

Acta Biochimica Polonica

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2009

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tom 56

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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.

3

Multidrug-resistant strains of coagulase-negative staphylococci isolated from patients with chronic sinusitis – MDR, XDR, PDR strains

86%

Michalik M. , Podbielska-Kubera A. , Samet A. , Konopka W.

Polish Journal of Otolaryngology

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2020

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tom 74

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nr 2

36-41

EN

Introduction: The development of resistance to multiple antimicrobial agents in pathogenic bacteria has become a threat to public health. Multidrug-resistant strains that are particularly dangerous include MDR, XDR and PDR strains. Material and methods: Aspirate material from paranasal sinuses, obtained from patients with chronic sinusitis undergoing functional endoscopic sinus surgery (FESS) in Medical Center MML in Warsaw, was subjected to bacteriologic analysis. The isolated strains were identified to the species level and tested for antibiotic resistance. Then, minimal inhibitory concentration (MIC) was determined. R esults: The isolated strains of coagulase-negative staphylococci were resistant mainly to macrolides, aminoglycosides and tetracycline. Nine of the isolated strains exhibited multidrug-resistance. Discussion: Bacteria causing chronic sinusitis are becoming increasingly resistant to antimicrobial agents. The diagnostic process for coagulase-negative staphylococci (CNS) is often limited to the identification of species, or even genus of the bacteria. The CNS strains are considered to be non-pathogenic and they are not subject to eradication. This may lead to erroneous therapeutic decisions and, consequently, to the development of antibiotic resistance. CNS infections are classified as nosocomial and therefore, appropriate epidemiological procedures have to be followed. The authors highlight the necessity to determine MIC values for antibiotics and to introduce personalized treatment.

4

Bakterie z rodzaju Erwinia sp. jako patogeny roślin

72%

Cieniuch G.

Laboratorium - Przegląd Ogólnopolski

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2019

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tom nr 3

40--43

PL

Bakterie mają duży wpływ na otoczenie, w którym żyją. Wśród wielu bakterii środowiskowych odnajdujemy także takie, które zasiedlają rośliny i mogą powodować ich choroby. Bakteriozy to choroby bakteryjne roślin, a ich objawy mogą dotyczyć: liści, kwiatów, owoców czy też pędów i korzeni. Jedne z bakterii fitopatogennych to bakterie z rodzaju Erwinia. U bakterii fitopatogennych z rodzaju Erwinia sp. najczęściej występującymi czynnikami wirulencji są: lipopolisacharydy, toksyny, egzopolisacharydy czy też enzymy zewnątrzkomórkowe. Erwinia amylovora jest czynnikiem etiologicznym zarazy ogniowej. E. rhapontici powoduje proces gnilny tkanek roślin. Zagrożeniem dla hodowli roślin strączkowych i pasz może być E. persicina.

EN

Bacteria have a big impact on the environment in which they live. Among many environmental bacteria, we can also find those that inhabit plants and can cause their diseases. Bacterioses are bacterial diseases of plants, and their symptoms may involve leaves, flowers, fruits or shoots and roots. One of the phytopathogenic bacteria are Erwinia species. In phytopathogenic bacteria from the genus Erwinia sp., the most common virulence factors are lipopolysaccharides, toxins, exopolysaccharides or extracellular enzymes. Erwinia amylovora is the etiological factor of the fire blight. E. rhapontici causes the decay of plant tissues. E. persicina may be a hazard for legumes and feed.

5

Czynniki zjadliwości Streptococcus pyogenes

72%

Szczypa K.

Laboratorium - Przegląd Ogólnopolski

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2015

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tom nr 7-8

34--38

PL

Streptococcus pyogenes jest głównym patogenem człowieka odpowiedzialnym za wiele chorób, począwszy od nieskomplikowanych do poważnych, o przebiegu inwazyjnym i zagrażającym życiu człowieka. Ciężkie zakażenia tym drobnoustrojem są powodem wysokiej śmiertelności, często pomimo wdrożenia odpowiedniego leczenia. S. pyogenes ma bardzo złożony mechanizm zjadliwości. Ilustruje to fakt, że dla tego pategenu opisano ponad 60 czynników odpowiedzialnych za jego wirulencję. Białko M i paciorkowcowe toksyny pirogenne wydają się obecnie najważniejszymi i dlatego zostały omówione w niniejszym opracowaniu.

EN

Streptococcus pyogenes is a major human pathogen responsible for numerous diseases ranging from uncomplicated to severe, life threatening invasive disease. These severe invasive infections progress rapidly and produce high rates of morbidity and mortality despite the implementation of aggressive treatment plans. S. pyogenes has very complex virulence mechanisms, which is ilustrated by the fact that more than 60 propertirs relating to this pathogen’s virulence have been described so far. M protein and streptococcal pyrogenic exotoxins seem to the most important structure for virulence, as discussed in this paper.

6

Using multitype branching models to analyze bacterial pathogenicity

72%

Tahir D. , Kaj I. , Bartoszek K. , Majchrzak M. , Parniewski P. , Sakowski S.

Mathematica Applicanda

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2020

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tom Vol. 48, no. 1

59--86

EN

We apply multitype continuous time Markov branching models to study pathogenicity in E. coli, a bacterium belonging to the genus Escherichia. First, we examine briefly the properties of multitype branching processes and we also survey some fundamental limit theorems regarding the behavior of such models under various conditions. These theorems are then applied to discrete, state dependent models in order to analyze pathogenicity in a published clinical data set consisting of 251 strains of E. coli. We use well established methods, incorporating maximum likelihood techniques, to estimate speciation rates as well as the rates of transition between diffrerent states of the models. From the analysis, we not only derive new results, but we also verify some preexisting notions about virulent behavior in bacterial strains.

PL

W celu zbadania patogenności szczepów E. coli, bakterii z rodzaju Escherichia, użyto wielorodzajowego markowskiego procesu gałązkowego z czasem ciągłym. W pierwszej kolejności zrobiono przegląd własności wykorzystywanego procesu wraz z najważniejszymi wynikami granicznymi opisującymi zachowanie procesu przy różnych założeniach. Następnie przyjęto konkretny model, w którym rozgałęzienia są zależne od stanu oraz zastosowano go do badania patogenności w zestawie 251 szczepów E. coli pochodzących z II Centralnego Szpitala Klinicznego Wojskowej Akademii Medycznej. Parametry modelu, tempa narodzin oraz mutacji, zostały uzyskane metodą największej wiarygodności. Przedstawiona w artykule analiza potwierdza znane własności patogenności bakterii oraz sugeruje nowe ścieżki pracy badawczej.

7

Czynniki wirulencji bakterii - białkowe fosfatazy tyrozynowe : jako cel terapeutyczny w odpowiedzi na rozwijającą się antybiotykooporność

72%

Kostrzewa T. , Styszko J. , Przychodzeń P. , Kamm A. , Górska-Ponikowska M. , Kuban-Jankowska A.

Wiadomości Chemiczne

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2019

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tom [Z] 73, 11-12

679--699

EN

Microbial virulence is the ability of pathogen to penetrate, replicate, multiplícate and, as a consequence, damage the cells of the infected organism. In recent years, rapid progress in bacterial genome sequencing has led to the discovery and characterization of many new virulence factors. One of the many mechanisms of bacterial virulence is the activity of bacterial kinases and phosphatases. These enzymes phosphorylate and dephosphorylate various amino acid residues in proteins, most commonly serine, tyrosine and threonine. Reversible phosphorylation and dephosphorylation can control the activity of target proteins, either directly, by inducing conformational changes in proteins, or indirectly, by regulating protein-protein interactions. Due to the increasing antibiotic resistance, new substances that could be used to treat diseases caused by resistant bacterial strains are sought. One of the possibilities seems to be the inhibition of bacterial tyrosine phosphatases. Phosphorylation of proteins containing tyrosine residues is a key post-translational modification that controls the numerous cellular functions in bacteria. So far, many tyrosine phosphatases have been found to be responsible for the virulence of various bacterial strains. Many bacterial species use protein tyrosine phosphatases activity in host-pathogen interaction, by affecting signalling pathways and subsequent induction of the infection process. Many studies are devoted to the search for tyrosine phosphatases inhibitors in the context of possible support of the current antibacterial treatment. This article presents a review of reports on bacterial virulence factors-protein tyrosine phosphatases as potential therapeutic targets.

8

Wybrane czynniki wirulencji i ich rola w patogenezie bakterii Salmonella sp.

58%

Dróżdż M.

Laboratorium Medyczne

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2019

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tom nr 2

47--50

PL

Infekcje wywołane przez pałeczki Salmonella sp. mogą być ograniczone tylko do przewodu pokarmowego, ale można także wyróżnić zakażenia układowe oraz zakażenia durowe i rzekomo durowe. Niniejsza praca ma na celu charakterystykę wybranych czynników wirulencji bakterii Salmonella sp. (system sekrecji typu III, lipopolisacharyd, rzęski, białka błony zewnętrznej i siderofory) odpowiedzialnych za pojawianie się objawów chorobowych i rozwój infekcji. Struktury te umożliwiają adhezję, rozprzestrzenianie się po organizmie, kolonizację i niszczenie komórek, a działanie synergistyczne poszczególnych czynników wirulencji wzmaga ich sukces chorobotwórczy.

EN

Infections caused by Salmonella sp. can be limited only to the digestive system, but systemic infections, typhoid fever and paratyphoid fever can be also distinguished. This paper aims to characterize selected virulence factors of Salmonella sp. (including the type III secretion system, lipopolysaccharide, cilia, outer membrane proteins and siderophores) responsible for the onset of the signs and symptoms of the disease and the development of infection. These structures enable adhesion, invasion through the cells, colonization and destruction of different tissues. The synergistic activity of these factors increase the pathogenic success of Salmonella sp.