All posts by Postępy Mikrobiologii

Sukcesor wirusa polio – enterowirus 71

Successor of polio virus – enterovirus 71
A. Krzysztoszek, M. Wieczorek
26 July 2017

1. Wstęp. 2. Budowa i klasyfikacja. 3. Receptory komórkowe i replikacja. 4. Przebieg zakażenia. 5. EV71 na świecie. 6. Genotypy EV71 i zmienność wirusa. 7. Patogeneza. 8. Prace nad szczepionką. 9. Zakończenie

Abstract: Enterovirus 71 (EV71) is one of the most important causes of hand, foot, and mouth disease. It can also cause severe complications of the central nervous system. Brain stem encephalitis with pulmonary edema is a severe complication that can lead to death. EV71 was first isolated in California in 1969. Since the late 1990s, EV71 has seriously affected the Asia-Pacific region. In recent years, there have been an increasing number of reports of HFMD outbreaks with fatal cases due to EV71 in Asian countries. Generally, EV-71 is divided into three broad genotypes: A, B and C, based on analysis of complete genome sequences of many strains. Recent studies suggest that recombination has played a crucial role in EV71 evolution. Poliovirus, another enterovirus, is nearly completely eradicated as a result of global immunization efforts. EV71 may become an important pathogen, replacing poliovirus, with increasing health threat to humans. Prevention of EV71 epidemics is likely to require the development of an effective vaccine. This is an important public health problem causing serious clinical illness and, potentially, death in young children.

1. Introduction. 2. Structure and classification. 3. Cellular receptors and replication. 4. Course of infection. 5. EV71 in the world. 6. EV71 genotypes and variability of the virus. 7. Pathogenesis. 8. Vaccine development. 9. Summary

Autor: Postępy Mikrobiologii
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Różnorodność szlaków utleniania białek Dsb (disulfide bond) w świecie mikroorganizmów

Diversity of the Dsb (disulfide bond) oxidative protein folding pathways in microbial world
A. Dobosz, K. M. Bocian-Ostrzycka, E. K. Jagusztyn-Krynicka
26 July 2017

1. Wprowadzenie. 2. Modelowy system szlaku utleniania Dsb Escherichia coli. 2.1. Charakterystyka białek EcDsbA i EcDsbB. 2.2. Szlaki utleniania i izomeryzacji/redukcji E. coli. 2.3. Rola motywu CXXC i pętli cis-Pro151 białka EcDsbA. 3. Różnorodność bakteryjnych szlaków oksydacji białek. 3.1. Zwielokrotniona liczba białek DsbA. 3.2. Różnorodność strukturalna monomerycznych białek DsbA. 3.3. Dimeryczne oksydoreduktazy DsbA. 3.4. Obecność lub brak białka pełniącego funkcję EcDsbB. 4. Specyficzność substratowa oksydoreduktaz DsbA. 4.1. Metody poszukiwania i lokalizacja substratów. 4.2. Czynniki wirulencji. 5. Inne systemy Dsb. 6. Podsumowanie

Abstract: The introduction of structural disulfide bonds is crucial to the stability and activity of many extra-cytoplasmic proteins. The disulfide bond formation is a rate-limiting step in the folding process of a protein. However, most microorganisms encode a machinery to catalyse this oxidative protein folding step. In prototypic Escherichia coli oxidative pathway, the introduction of disulfide bridges into folding proteins is mediated by the thioredoxin family members – Dsb system proteins. Correct oxidative protein folding in the E. coli envelope depends on both EcDsbA and EcDsbB. Periplasmic oxidoreductase EcDsbA is a key disulfide bond formation catalyst, which is maintained in its active form by membrane-bound protein EcDsbB. To date, over 300 EcDsbA homologues from different bacterial organisms have been identified. Nevertheless, the structure, function and interactions of EcDsbA still remain the best studied. The rapidly expanding number of sequenced bacterial genomes has revealed dramatic differences between the model E. coli oxidative pathway and the pathway in other microorganisms. In this article, we review current knowledge about EcDsbA and focus on the diversity of the disulfide bond generation pathways functioning in the microbial world.

1. Introduction. 2. The classical Escherichia coli thiol oxidizing pathway. 2.1. Characteristics of EcDsbA and EcDsbB proteins. 2.2. E. coli oxidative and isomerization/reduction pathways. 2.3. The role of EcDsbA CXXC motif and cis-Pro151 loop. 3. Variety of bacterial oxidative pathways. 3.1. Multiplied number of DsbAs. 3.2. Structural diversity of monomeric DsbA proteins. 3.3. Dimeric DsbA oxidoreductases. 3.4. The presence or absence of a protein acting as EcDsbB. 4. Substrate specificity of DsbA oxidoreductases. 4.1. Procedures for DsbA substrates identification and methods of location analysis. 4.2. Virulence associated with DsbA substrates. 5. Other Dsb systems. 6. Conclusions

Autor: Postępy Mikrobiologii
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Yarrowia lipolytica – niekonwencjonalne drożdże w biotechnologii

Yarrowia lipolytica – non-conventional yeast in biotechnology
J. Krzyczkowska, A. Urszula Fabiszewska
26 July 2017

1. Wprowadzenie. 2. Taksonomia i bioróżnorodność gatunku Yarrowia lipolytica. 3. Morfologia i fizjologia drożdży Yarrowia lipolytica. 4. Charakterystyka genetyczna Yarrowia lipolytica. 5. Biotechnologiczne znaczenie drożdży Yarrowia lipolytica. 5.1. Rola drożdży Yarrowia lipolytica w biotechnologii żywności. 5.2. Yarrowia lipolytica w ochronie środowiska. 5.3. Synteza białek enzymatycznych przez drożdże Yarrowia lipolytica. 6. Podsumowanie

Abstract: Yarrowia lipolytica is one of the most extensively studied “non-conventional” yeast. It is considered as nonpathogenic and several processes based on this organism were generally recognized as safe (GRAS) by the Food and Drug Administration (FDA, USA). Numerous unique physiological as well as biochemical properties exhibited by these microorganisms allow their wide use in biotechnology of food. High secretory capacity contributes to the production of a number of important metabolites, including organic acids, polyalcohols, carotenoids, aroma compounds, single cell oil or microbial surfactants. The sequenced genome and fairly well studied metabolism of this yeast species allows also for its usage as a model in numerous basic research in the field, including secretory protein, biogenesis of peroxisomes or lipid homeostasis. In this review, we have summarizedthe potential applications of the yeast Y. lipolytica, including the commercialization of some processes. The article provides also a synthetic description of the systematics, morphology and physiology of the species.

1. Introduction. 2. Taxonomy and biodiversity of species of Yarrowia lipolytica. 3. The morphology and physiology of the yeast Yarrowia lipolytica. 4. Genetic characteristics of Yarrowia lipolytica. 5. Biotechnological importance of yeast Yarrowia lipolytica. 5.1. The role of the yeast Yarrowia lipolytica in the biotechnology of food. 5.2. Yarrowia lipolytica in environmental protection. 5.3. Synthesis of enzymes by yeast Yarrowia lipolytica. 6. Summary

Autor: Postępy Mikrobiologii
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Grzyby z rodzaju Scopulariopsis – mało znane patogeny człowieka

Fungi of the genus Scopulariopsis – ill-defined human pathogens
M. Skóra, J. Bielecki, M. Bulanda, A. B. Macura, T. Jagielski
26 July 2017

1. Wprowadzenie. 2. Pozycja taksonomiczna. 3. Morfologia. 4. Występowanie. 5. Znaczenie w medycynie człowieka. 5.1. Grzybice skóry i paznokci. 5.2. Inne postacie zakażeń. 6. Diagnostyka zakażeń. 7. Wrażliwość na leki przeciwgrzybicze. 8. Leczenie. 9. Podsumowanie. 10. Piśmiennictwo

Abstract: The genus Scopulariopsis accommodates more than 30 species of mitosporic moulds. Their natural habitat is the soil, where they live as saprophytes and are involved in the decomposition of organic matter. However, some members of the Scopulariopsis genus may cause opportunistic infections in humans. Superficial skin lesions and onychomycosis in particular are the most predominant clinical manifestations. Much rarer are subcutaneous, deep tissue and disseminated infections, most of which occur in immunocompromised individuals and are associated with high mortality. Treatment of Scopulariopsis infections is difficult and usually empirically-based, one reason for this being resistance of Scopulariopsis spp. to a broad spectrum of antifungal agents. Identification of pathogenic Scopulariopsis spp. still largely relies on the phenotype-based methods, employing both morphological and biochemical criteria. These methods require highly qualified personnel and are usually considered as slow and laborious, often leading to misidentification. Therefore, molecular diagnostic methods are preferred, since they provide rapid, high-throughout, unambiguous and highly specific identification of fungal pathogens. Earlier attempts to develop assays for detecting Scopulariopsis spp. resulted in limited success. These assays, almost exclusively based on the hypervariable regions of the large subunit (LSU) rRNA, often produce inconclusive results and, more importantly, lack specificity, being unable to discriminate between different Scopulariopsis spp. Hence, currently available molecular methods do not allow inter- and intra-species differentiation of Scopulariopsis fungi.

1. Introduction. 2. Taxonomic position. 3. Morphology. 4. Distribution. 5. Significance in human medicine. 5.1. Skin and nail mycoses. 5.2. Other forms of infections. 6. Diagnosis of infections. 7. Antifungal susceptibility. 8. Treatment. 9. Summary. 10. References

Autor: Postępy Mikrobiologii
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Antygeny powierzchniowe i czynniki wirulencji Escherichia coli O157

Cell-surface antigens and virulence factors of Escherichia coli O157
J. Kutkowska, M. Michalska-Szymaszek, R. Matuszewska, E. Chmiel, T. Urbanik-Sypniewska
26 July 2017

1. Wstęp. 2. Występowanie w środowisku i źródła zakażenia bakteriami EHEC E. coli O157. 3. Patogeneza. 3.1. Objawy kliniczne zakażenia E. coli EHEC. 4. Czynniki wirulencji kodowane na plazmidach. 5. Antygen O; struktura, biosynteza, znaczenie w chorobotwórczości i jako markera w diagnostyce. 6. Antygeny H serotypu O157. 7. Identyfikacja E. coli O157. 8. Epidemie EHEC E. coli przenoszące się drogą wodną. 9. Zapobieganie. 10. Podsumowanie

Abstract: Shiga toxin-producing Escherichia coli (STEC) strains are commensal bacteria in cattle with high potential for transmission to humans. The serotype E. coli O157:H7 is the main cause of hemorrhagic colitis and hemolytic-uremic syndrome. E. coli O157 synthesizes an O-antigen containing a repeating tetrasaccharide with the structure (4-N-acetyl-perosamine →3-fucose →3-glucose →3-N-acetyl-galactosmine). The presence of a common epitope consisting of 2-substituted N-acyl-perosamine is responsible for the serological cross-reactions with Yersinia enterocolitica O9 or Vibrio cholerae O1. The sequence homology indicates that the O157:H7 rfbE gene encoding perosamine synthetase may have originated in a species other than E. coli. The peculiarity of O157 repeat unit biosynthesis is a new pathway performed by epimerase Gnu that catalyses the reversible epimerization of N-acetyl-glucosamine-P-P-undecaprenol to N-acetyl-galactosmine-P-P-undecaprenol. The potential of the bacterial epimerase as a new target for antimicrobial agents is discussed. O157 and H7 antigens seem to be accessory virulence factors implicated in the pathogenesis of human diseases. The O157 antigen is important in the animal and plant host immune response and plays a role in the adherence of this organism to epithelial cells. One of the sources of epidemic outbreaks is water from the municipal water supply and other reservoirs. Survival of O157 bacteria in water environments has been recorded. The comparative analysis of nucleotide sequences within the rfb O antigen gene cluster and of other genes in the genome among STEC strains will elucidate the genetic basis of the evolution and virulence of these enteric pathogens.

1. Introduction. 2. Environmental occurrence and sources of EHEC E. coli O157 infections. 3. Pathogenesis. 3.1. Clinical symptoms of E. coli EHEC infection. 4. Plasmid-encoded virulence factors. 5. The O-antigen; the structure, biosynthesis and the role in pathogenesis and as a diagnostic marker. 6. H antigens of the O157 serotype. 7. E. coli O157 identification. 8. Waterborne EHEC outbreakes. 9. Prevention. 10. Summary

Autor: Postępy Mikrobiologii
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Advancements of Microbiology
Volume 63 (2024): Issue 3

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PTM

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