All posts by Postępy Mikrobiologii

Drożdże jako potencjalne źródło tłuszczu mikrobiologicznego

Yeast as a potential source of microbial fat
A. M. Kot, S. Błażejak, A. Kurcz, I. Gientka
20 July 2017

1. Wstęp. 2. Mikroorganizmy olejogenne. 3. Enzymatyczne drogi syntezy tłuszczu w komórkach drożdży. 3.1. Biosynteza tłuszczu de novo. 3.2. Biosynteza tłuszczu ex novo. 4. Czynniki wpływające na proces biosyntezy tłuszczu. 5. Próby doskonalenia genetycznego drożdży olejogennych. 6. Ekstrakcja tłuszczu z komórek drożdży. 7. Możliwości przemysłowego zastosowania tłuszczu mikrobiologicznego. 8. Podsumowanie

Abstract: The yeast which can produce more than 20% lipids in their dry matter are called oleaginous and belong mainly to the genera Yarrowia, Rhodotorula, Rhodosporidium, Cryptococcus, Trichosporon and Lipomyces. The synthesis and storage of fat in yeast cells can be achieved via two pathways. In the first method – de novo, the acetyl-CoA and malonyl-CoA molecules are substrates of the lipid for the synthesis, while in the ex novo method, the hydrophobic compounds present in the environment are utilized. The process of lipid biosynthesis in yeast cells is affected by environmental factors such as carbon and nitrogen source in the medium, the C/N molar ratio, pH, temperature and the time of the cultivation. Microbial synthesis as the type of fat production process has many advantages, since it is insusceptible to weather conditions and the season of the year. Moreover, yeast show a rapid growth rate, which significantly shortens the production cycle. The main drawback of the industrial SCO production is low fat yield per unit of culture medium, which increases the total cost of the project. Microbiological fat synthesized by yeast might be used as a substitute for vegetable oils in human nutrition or as a substrate for the production of biodiesel.

1. Introduction. 2. Oleaginous microorganisms. 3. Enzymatic synthesis pathways of fat in yeast cells. 3.1. De novo lipid accumulation. 3.2. Ex novo lipid accumulation. 4. Factors affecting the biosynthesis of fat. 5. Attempts to genetically improve oleaginous yeast. 6. Extraction of fat from yeast cells. 7. Industrial applicability of microbial fat. 8. Conclusions

Autor: Postępy Mikrobiologii
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Compartmentalization in cephalosporin C biosynthesis by industrial strains Acremonium chrysogenum

Ultrastrukturalna organizacja komórek grzybni Acremonium chrysogenum podczas produkcji cefalosporyny C na skalę przemysłową
W. Kurzątkowski, A. Gębska-Kuczerowska
20 July 2017

1. Introduction. 2. The pathway of cephalosporin C biosynthesis. 3. Secondary metabolism of cephalosporin C. 4. Cellular localization of enzymes involved in cephalosporin C biosynthesis (compartmentalization). 5. Role of peroxisomes in cephalosporin C biosynthesis. 6. Industrial strain improvement. 7. β-lactams in the treatment of various bacterial infections – mode of action. 8. Conclusions

Abstract: Cephalosporin C biosynthesis is a compartmentalized process located mainly in the sub-apical, productive, non-growing cells of the hyphae, which under the conditions of the industrial technology build well-dispersed flocculent mycelia. In this paper, the cephalosporin C production by industrial strains of Acremonium chrysogenum (syn. Cephalosporium acremonium) is described, including the central role of peroxisomes in the biosynthesis and secretion of this antibiotic and other β-lactams. The localization of the pathway of cephalosporin C biosynthesis and important transport steps of intermediates and the end-products are also discussed.

1. Wprowadzenie. 2 Szlak biosyntezy cefalosporyny C. 3. Wtórny metabolizm cefalosporyny C. 4. Lokalizacja enzymów biosyntezy cefalosporyny C w komórkach producenta. 5. Rola peroksysomów w biosyntezie cefalosporyny C. 6. Zwiększanie wydajności szczepów przemysłowych. 7. Rola antybiotykow β-laktamowych w lecznictwie – mechanizm działania antybiotyków β-laktamowych. 8. Wnioski

Streszczenie: W niniejszej pracy omówiono rolę peroksysomów w wytwarzaniu cefalosporyny C przez przemysłowe szczepy A. chrysogenum. Przedstawiono lokalizację enzymów szlaku biosyntezy cefalosporyny C w dojrzałych metabolicznie aktywnych nierosnących komórkach grzybni. Omówiono także niektóre aspekty zwiększania wydajności szczepów przemysłowych.

Autor: Postępy Mikrobiologii
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Modyfikacje struktur komórkowych mikroorganizmów wywoływane działaniem biocydów

Modifications of cell structure of microorganisms induced by biocides
E. Krzyżewska, M. Książczyk, A. Kędziora, B. Futoma-Kołoch, G. Bugla-Płoskońska
20 July 2017

1. Wprowadzenie. 2. Oporność mikroorganizmów na biocydy. 3. Oporność bakterii na biocydy determinowana przez geny znajdujące się na plazmidzie. 4. Zmiana ultrastruktury składników osłon komórkowych, jako odpowiedź komórki bakterii na działanie biocydów. 4.1. Modyfikacje lipopolisacharydu bakterii Gram-ujemnych. 4.2. Modyfikacje białek błony zewnętrznej oraz pompy efflux jako główny system oporności na biocydy bakterii Gram-ujemnych. 5. Biofilm bakteryjny jako strategia ochronna przed działaniem substancji biobójczych. 6. Oporność krzyżowa bakterii na biocydy i antybiotyki. 7. Podsumowanie

Abstract: Interactions between bacterial cells and antimicrobial agents, including disinfectants, are still not well investigated and understood, especially in terms of bacterial insusceptibility to biocides. Facing increasing and deepening multidrug resistance phenomenon among pathogenic bacteria, disinfection is one of the most popular and effective non-antibiotic control and elimination method of pathogen dissemination. If disinfection is supposed to be an alternative solution to antibiotic therapy, it needs to be confirmed that multidrug resistance would not be resplaced by an even more dangerous phenomenon, i.e. microbial resistance to biocides. Hence, it is essential to investigate this issue. Recently, there have been a lot of research about interactions between microorganisms and biocides, which is reflected in the numerous publications available in the Pub-Med database (649 from years 2009–2014). What is more, since 2013/2014 the BacMet database,which contains sequences and information about genes associated with microbial susceptibility to biocides, is available on-line. Better understanding of bacterial molecular response to biocides might reveal some unknown and important interactions.

1. Introduction. 2. Resistance to biocides. 3. Biocide resistance determined by genes contained on plasmids. 4. Changes of bacterial cell envelope in response to biocides. 4.1. Modification of bacterial lipopolysaccharides. 4.2. Modifications of outer membrane proteins and efflux pumps as the main system of bacterial resistance to biocides of Gram-negative bacteria. 5. Bacterial biofilm as a protective strategy against biocides. 6. Cross-resistance of bacteria to biocides and antibiotics. 7. Summary

Autor: Postępy Mikrobiologii
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Mechanizmy oporności Acinetobacter baumannii na związki przeciwbakteryjne

Acinetobacter baumannii: mechanisms of resistance to antibacterial agents
A. Namysłowska, A. E. Laudy, S. Tyski
20 July 2017

1. Wstęp. 2. Oporność na antybiotyki β-laktamowe. 2.1. Enzymy CHDL. 2.2. Enzymy MBL. 2.3. Karbapenemazy należące do klasy A wg Amblera. 2.4. Nabyte enzymy ESβL hamowane przez inhibitory β-laktamaz. 2.5. Enzymy AmpC. 3. Oporność na antybiotyki inne niż β-laktamy. 3.1. Oporność na chinolony i fluorochinolony. 3.2. Oporność na aminoglikozydy. 3.3. Oporność na kolistynę. 4. Aktywne usuwanie antybiotyków z komórki bakteryjnej przy udziale pomp błonowych – mechanizm efflux. 4.1. System pomp RND. 4.2. Inne systemy pomp błonowych. 5. Kanały błonowe – pory. 6. Biofilm i zjawisko quorum sensing. 7. Podsumowanie

Abstract: Acinetobacter baumannii has become one of the most dangerous Gram-negative bacterial species, causing numerous infections over the last 20 years. A. baumannii is responsible for nosocomial ventilator-associated pneumonia (VAP), urinary tract infections, meningitidis and bacteremia. Its remarkable ability to acquire resistance determinants against multiple antibiotics of different classes and to tolerate harsh environments resulted in the dissemination of multi-drug-resistant (MDR) strains. Diverse mechanisms of resistance limit therapeutic options and make the infections difficult to treat. The described resistance mechanisms include: production of β-lactamases, i.e. enzymes modifying structure of antibiotics, activity of efflux pumps, loss of membrane porins and formation of biofilm.

1. Introduction. 2. Resistance to β-lactams. 2.1. CHDLs. 2.2. MBLs. 2.3. Ambler class A carbapenemases. 2.4. Acquired ESβLs inhibited by clavulanic acid. 2.5. AmpC enzymes. 3. Resistance to antibiotics other than β-lactams. 3.1. Resistance to quinolones and fluoroquinolones. 3.2. Resistance to aminoglycosides. 3.3. Resistance to colistin. 4. Efflux systems. 4.1. RND efflux system. 4.2. Other efflux systems. 5. Outer membrane porins. 6. Biofilm and quorum sensing process. 7. Summary

Autor: Postępy Mikrobiologii
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Metody oparte na amplifikacji kwasów nukleinowych w diagnostyce wybranych chorób przenoszonych drogą płciową

Nucleic acid amplification methods in laboratory diagnostics of selected sexually transmitted diseases
B. Młynarczyk-Bonikowska, E. Skulska, M. Malejczyk, S. Majewski
19 July 2017

1. Wstęp. 2. Metoda PCR i jej modyfikacje, które znalazły zastosowanie w diagnostyce STI. 3. Opryszczka narządów płciowych. 4. Zakażenia genitalnymi HPV. 5. Rzeżączka. 6. Zakażenia Chlamydia trachomatis. 7. Kiła. 8. Równoczesne wykrywanie kilku patogenów. 9. Podsumowanie

Abstract: Sexually transmitted diseases (STDs) are common in the world’s human population and are often asymptomatic. On the other hand, STDs are highly infective and connected with considerable morbidity and mortality. Therefore, using fast, sensitive and specific diagnostic methods is especially important. Polymerase chain reaction – PCR, invented thirty years ago by the Nobel prize winner Carry Mullis, revolutionized many fields of biological sciences, including laboratory diagnostics of infectious diseases. In this review, we discuss the application of nucleic acid amplification techniques (NAATs), including PCR, multiplex PCR, real time PCR and HDA-helicase dependent amplification, in the laboratory diagnostics of sexually transmitted diseases. Nucleic acids amplification tests are widely used in diagnostics of some STD-like genital herpes, Chlamydia trachomatis infection and gonorrhoea. In other diseases, like genital HPV infections, NAATs are used only in some indications. In the case of syphilis, there are no commercial tests and it was proven that NAATs are not sensitive and specific enough to be used routinely as a substitute to serologic methods. We compare NAATs with some other methods used in laboratory diagnostics of individual diseases, like serology, culture or direct immunofluorescence. In addition, we discuss limitations of the NAATs i.e. problems with their specificity in diagnostics of pharyngeal gonorrhoea. We also present the recommendations of the Centers for Disease Control and Prevention (CDC) and International Union Against Sexually Transmitted Diseases (IUSTI).

1. Introduction. 2. PCR method and its modifications which can be applied in diagnostics of STIs. 3. Genital herpes. 4. Infections with genital HPVs. 5. Gonorrhoea. 6. Chlamydia trachomatis infections. 7. Syphilis. 8. Simultaneous detection of several pathogens. 9. Summary

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Advancements of Microbiology
Volume 63 (2024): Issue 1

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PTM

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