All posts by Postępy Mikrobiologii

Wirofagi – nowe elementy biologiczne

Virophages – new biological elements
B. Tokarz-Deptuła, J. Śliwa-Dominiak, M. Adamiak, M. Kubiś, A. Ogórkiewicz, W. Deptuła
21 July 2017

1. Wprowadzenie. 2. Wirofag Sputnik. 3. Wirofag Sputnik 2. 4. Wirofag Mawirus. 5. Wirofag OLV. 6. Inne wirofagi. 7. Wirofagi a wirusy satelitarne. 8. Podsumowanie

Abstract: Virophages are viruses whichinfect mainly giant viruses, from so-called super-family NCLD (nucleocytoplasmic large DNA viruses), which includes Mimivirus, Mamavirus, Lentille, CroV or Phycodna virus. They occurre in the aquatic environment as infectious agents, especially for protozoa, flagellates, algae and micro-algae (mainly Spirulina sp. and Chlorella sp.). The first known virophage was Sputnik, for which the dominant host is Mamawirus living on the protozoa Acanthamoeba (A.) polyphaga. However, it can infect also Mimivirus living on protozoa A. castellanii. Sputnik was also considered as satellite virus, as its replication cycle requires the presence of Mamavirus or Mimivirus and also its genetic material is DNA,. Thus, it is the first described dsDNA satellite virus. This virophage has its own gene encoding the capsid and its replication takes place in the Mamavirus and/or Mimivirus “factories”, creating a link between viruses and the animated world. The second discovered virophage after Sputnik was Sputnik 2, which was found in amoeba contaminated fluid (Acantamoeba polyphaga) infected with the giant virus – Lentille. Sputnik 2, similarly to Sputnik, has the ability to introduce its DNA into the host genome, as evidenced by the discovery of its small fragments in the Lentille virus genome. The third discovered virophage was Mavirus, for which the host is a CroV virus (Cafeteria roenbergensis virus) infecting algae Cafeteria (C.) roenbergensis. Mavirus differs from Sputnik and Sputnik 2 as its cubic capsid has a diameter of 60 nm and its genome was found to be closely related to the class of eukaryotic DNA transposons Thus, it has been proposed that Mavirus might have given a start to DNA transposons in Maverick/Polinton class. The fourth described virophage is the Organic Lake Virophage (OLV). It has been identified by similarity in its capsid protein sequence to the already discovered protein sequences in Sputnik. In addition to the four virophages described in this work, there are also other registered virophages, such as Yellowstone Lake Virophage (YSLCV) 1, 2, 3, 4 and Ace Lake Mavirus – ALM.

1. Introduction. 2. Sputnik virophage. 3. Sputnik 2 virophage. 4. Mavirus virophage. 5. OLV virophage. 6. Other virophages. 7. Virophages and satellite viruses. 8. Summary

Autor: Postępy Mikrobiologii
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Czynniki wirulencji grzybów z rodzaju Candida istotne w patogenezie zakażeń występujących u pacjentów żywionych pozajelitowo

Virulence factors of Candida species important in the pathogenesis of infections in patients with total parenteral nutrition
M. Sikora, M. Gołaś, K. Piskorska, E. Swoboda-Kopeć
21 July 2017

1. Wstęp. 2. Czynniki ryzyka wystąpienia zakażenia o etiologii grzybiczej. 3. Czynniki wirulencji grzybów drożdżopodobnych z rodzaju Candida. 4. Zjawisko wzrostu w postaci biofilmu. 5. Sekrecja enzymów hydrolitycznych. 6. Zjawisko dimorfizmu. 7. Podsumowanie

Abstract: Fungal infections constitute a vital clinical issue concerning various groups of patients, among them patients with total parenteral nutrition. The most common etiological infection factors, affecting the aforementioned group of patients, are among others yeastlike fungi. In clinical specimens, the predominant genus of yeastlike fungi, as isolated from the patients with total parenteral nutrition, is Candida spp. The species of yeastlike fungi of the Candida genus generate various pathogenic factors enabling invasion process and the progression of the subsequent infection stages. The most crucial of them are:
• ability to adhere and ability to form biofilms. This feature, with the mediation of adhesion proteins, enables the fungi to grow on the biomaterial surfaces, to invade the host’s tissue, and conditions survival and existence in the environment;
• dimorphism. Creation of two antigenically different forms – yeast and hyphae – conditions specific escape from the immunological system of the macroorganism;
• high enzymatic activity. Hydrolytic, proteolytic and lipolytic activity, featuring primarily the adaptative function, is the indicator of the metabolic stimulation required for the infection process,
Due to the insignificant pathogenic potential of the Candida genus fungi, associated with the fact of their natural existence on skin and mucous membrane, the research is currently often directed at detection of the factors responsible for the colonisation and development of the fungal infections. These research attempts are aimed at differentiating between both processes.

1. Introduction. 2. Risk factors of fungal infections. 3. Virulence factors of the Candida genus. 4. The phenomenon of biofilm formation. 5. Hydrolytic enzymes secretion. 6. Dimorphism. 7. Conclusions

Autor: Postępy Mikrobiologii
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Mikrobiologiczne aspekty gospodarki gnojowicą

Microbiological aspects of slurry management
K. Skowron, J. Bauza-Kaszewska, A. Kaczmarek, A. Budzyńska, E. Gospodarek
21 July 2017

1. Wstęp. 2. Mikroflora gnojowicy. 3. Możliwości mikrobiologicznej kontaminacji środowiska. 4. Problem antybiotykooporności wśród szczepów z produkcji zwierzęcej. 5. Metody higienizacji gnojowicy na cele rolnicze. 6. Podsumowanie

Abstract: The animal manure may be a source of many pathogenic microorganisms, including Salmonella spp., Escherichia coli, Listeria monocytogenes, Yersinia enterocolitica or Campylobacter spp. The agricultural utilization of slurry poses a serious threat related to the transfer of pathogens to the environment. Some of the bacterial strains are antibiotic-resistant and their resistance genes can be transferred horizontally to the soil microflora. In order to avoid the pathogens’ transmission into the environment, different methods of slurry disinfection are necessary. Biological treatment seems to be the most common technique of slurry hygienization. Storage, anaerobic digestion, aeration or composting may result in effective reduction of pathogen level and guarantee biosafety of slurry application as soil fertilizer. Physical and chemical methods are not commonly used due to their reduced effectiveness in slurry decontamination and relatively high costs.

1. Introduction. 2. Microflora of slurry 3. The possibility of microbial contamination of the environment. 4. The problem of antibiotic resistance of strains from animal production. 5. Methods of slurry hygienization for agricultural purposes. 6. Summary

Autor: Postępy Mikrobiologii
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Leukocydyna Panton-Valentine – aspekty znane i nieznane

Panton-Valentine leukocidin – known and unknown aspects
J. Karakulska, P. Nawrotek, K. Fijałkowski
21 July 2017

1. Wstęp. 2. Struktura toksyny PVL. 3. Geny PVL i regulacja ich ekspresji. 4. Mechanizm działania toksyny PVL. 5. Znaczenie kliniczne szczepów produkujących toksynę PVL. 6. Badania na modelach zwierzęcych. 7. Metody detekcji toksyny PVL. 8. Podsumowanie

Abstract: Panton-Valentine leukocidin (PVL) is a two component pore-forming cytotoxin composed of LukS-PV and LukF-PV subunits, which mainly acts on mammalian neutrophils, monocytes and macrophages. The mechanism of action of PVL and its role in the pathogenesis of staphylococcal infections are still poorly understood. In vitro studies showed a concentration-dependent cytotoxic effect of PVL (formation of pores in the cell membrane), leading to apoptosis or necrosis of phagocytes. Nevertheless, it should be emphasized that, to date, it has not been proven that causing damage to phagocytes is the main function of PVL in vivo. It is known, however, that the concentration of PVL in vivo is not sufficient to induce cytolysis. Furthermore, it has been shown that sublithic concentration of PVL in vivo can activate and intensify bactericidal properties of phagocytes. Nowadays, PVL is epidemiologically linked mainly to community-associated methicillin-resistant S. aureus infections. There are also available, though very limited, data concerning the isolation of pvl-positive MRSA and MSCNS strains from domestic and farm animals.

1. Introduction. 2. The structure of the PVL toxin. 3. PVL genes and the regulation of their expression. 4. The mechanism of action of PVL toxin. 5. The clinical significance of strains producing PVL toxin. 6. Studies on animal models. 7. PVL toxin detection methods. 8. Summary

Autor: Postępy Mikrobiologii
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Bokawirus człowieka – charakterystyka, chorobotwórczość, występowanie

Human bocavirus – characteristics, pathogenicity, occurrence
E. Abramczuk, K. Pancer, W. Gut, B. Litwińska
21 July 2017

1. Wstęp. 2. Epidemiologia zakażeń HBoV. 3. Charakterystyka bokawirusów człowieka 4. Mechanizmy umożliwiające przetrwanie genomu HBoV w zakażonej komórce. 5. Odpowiedź immunologiczna na zakażenie HBoV. 6. Laboratoryjna diagnostyka zakażeń bokawirusami. 7. Bokawirusy a zakażenia mieszane. 8. Podsumowanie

Abstract: In this article, the characteristics of human Bocaviruses (HBoV) are presented. The viruses were described for the first time in 2005. The symptoms of HBoV infection are: cough, coryza, sore throat, breathing difficulty, but also nausea, vomiting and diarrhea. Four types of Bocaviruses are associated with human respiratory and gastrointestinal tract infections. HBoV1 is the main etiologic agent of respiratory tract infections, whereas HBoV2 causes gastrointestinal diseases. Bocaviruses can cause mild, asymptomatic infections as well as severe respiratory diseases, like pneumonia and bronchiolitis. HBoV2 is the third agent, after Rotaviruses and Astroviruses, which causes acute gastroenteritis in children. The treatment of HBoV infections is usually symptomatic The HBoV diagnosis is mainly based on molecular technics, such as quantitative PCR, serological tests are only used for epidemiological purposes. Infections due to HBoV occur during the whole human life, but they are most frequent in children from 6 month- to 3 year-old. HBoV infections are commonall over the world and, when detected, in Poland too. Infections occur throughout the year, but are most common in the winter season. The high rate of co-detection of HBoV with other viruses has been reported (82% samples). HBoV2 is the most frequently identified virus in co-infections with Noroviruses, Rotaviruses and Astroviruses, while HBoV1 – with RSV and HMPV.

1. Introduction. 2. Epidemiology of HBoV infections. 3. Characteristics of human bocavirus. 4. Mechanisms allowing survival of the genome HBoV in the infected cell. 5. The immune response to infection of HBoV. 6. Laboratory diagnostic HBoV infections. 7. Bocaviruses andco-infections. 8. Summary

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Advancements of Microbiology
Volume 63 (2024): Issue 3

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PTM

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