All posts by Postępy Mikrobiologii

ANTIBIOTIC BIOSYNTHESIS AND SECONDARY METABOLISM IN HIGH-YIELDING STRAINS OF STREPTOMYCES, PENICILLIUM CHRYSOGENUM AND ACREMONIUM CHRYSOGENUM

Biosynteza abtybiotyków i metabolitów wtórnych przez wydajne szczepy Streptomyces, Penicillium chrysogenum i Acremonium chrysogenum
Wiesław Kurzątkowski, Joanna Kuczerowska

1. Introduction. 2. Industrial strain improvements. 3. The pathways of antibiotic biosynthesis by Streptomyces spp. 4. Compartmentalization in antibiotic biosynthesis by Streptomyces spp. 5. The pathway of penicillin G biosynthesis by Penicillium chrysogenum. 6. Compartmentalization in penicillin G biosynthesis by Penicillium chrysogenum. 7. The pathway of cephalosporin C biosynthesis by Acremonium chrysogenum. 8. Compartmentalization in cephalosporin biosynthesis by Acremonium chrysogenum. 9. The future of antibiotic therapy. 10. Conclusions

Abstract: In this article, the secondary metabolism as a basis for antibiotics production by industrial strains of Streptomyces, Penicillium chrysogenum and Acremonium chrysogenum is discussed. Images from transmission electron microscopy reveal some important features of the mycelial cells which are related to antibiotics biosynthesis. This discovery is important for further industrial strain improvement and has economic significance. Possibilities of new strategies for antimicrobial treatment are discussed.

 

1. Wprowadzenie. 2. Ulepszanie szczepów przemysłowych. 3. Szlaki biosyntezy antybiotyków wytwarzanych przez Streptomyces spp. 4. Organizacja komórek grzybni Streptomyces spp. podczas biosyntezy antybiotyków. 5. Szlak biosyntezy penicyliny G w komórkach grzybni Penicillium chrysogenum. 6. Organizacja komórek grzybni Penicillium chrysogenum podczas biosyntezy penicyliny G. 7. Szlak biosyntezy cefalosporyny C w komórkach grzybni Acremonium chrysogenum. 8. Organizacja komórek grzybni Acremonium chrysogenum podczas biosyntezy cefalosporyny C. 9. Przyszłość antybiotykoterapii. 10. Wnioski

Streszczenie: Rola wtórnego metabolizmu w biosyntezie antybiotyków wytwarzanych przez szczepy przemysłowe z rodzaju Streptomyces oraz Penicillium chrysogenum i Acremonium chrysogenum jest dyskutowana. Obrazy z transmisyjnej mikroskopii elektronowej wykazują ważne cechy komórek grzybni związane z wysokowydajną biosyntezą antybiotyków. Odkrycie to pozwala na dalsze zwiększanie antybiotycznej wydajności szczepów przemysłowych i ma znaczenie ekonomiczne. Przedmiotem niniejszej publikacji jest omówienie możliwości opracowania nowych strategii zwalczania chorób zakaźnych.

PEŁZAKI Z RODZAJU ACANTHAMOEBA – CZYNNIKI ETIOLOGICZNE STANÓW PATOLOGICZNYCH LUDZKIEGO ORGANIZMU

Amoebae of the genus Acanthamoeba – pathological agents in humans
Marcin Padzik, Edyta B. Hendiger, Jacek P. Szaflik, Lidia Chomicz

1.Wprowadzenie. 2. Rodzaj Acanthamoeba. 2.1. Występowanie. 2.2. Chorobotwórczość. 3. Pełzakowe zapalenie rogówki – AK. 3.1. Czynniki ryzyka. 3.2. Przebieg zarażenia. 3.3. Diagnostyka. 3.4. Leczenie i profilaktyka. 4. Ziarniniakowe pełzakowe zapalenie mózgu – GAE. 4.1. Przebieg zarażenia. 4.2. Diagnostyka i leczenie. 5. Akantameboza skórna. 5.1. Przebieg zarażenia. 5.2. Diagnostyka i leczenie. 6. Podsumowanie

Abstract: Free living, cosmopolitan amoebae of the genus Acanthamoeba present a serious risk to human health. As facultative human parasites, these amoebae may cause health and life-threatening diseases, such as Acanthamoeba keratitis (AK), granulomatous amoebic encephalitis (GAE) and cutaneous acanthamebiasis. AK is a severe, vision-threatening cornea infection with non-specific symptoms and course. GAE is a unique central nervous system disease, almost always leading to death. Cutaneous acanthamebiasis is most common in patients with AIDS. The pathogenesis and pathophysiology of the diseases is still incompletely understood, therefore no definitive effective therapy is currently available. Prevention is very difficult due to Acanthamoeba ubiquity and resistance. Further studies on effective solutions for the prevention and treatment of Acanthamoeba infections are needed.

1. Introduction. 2. Genus Acanthamoeba. 2.1. Occurrence. 2.2. Pathogenicity. 3. Acanthamoeba keratitis – AK. 3.1. Risk factors. 3.2. Course of the disease. 3.3. Diagnostics. 3.4. Treatment and prevention. 4. Granulomatous amebic encephalitis – GAE. 4.1. Course of disease. 4.2. Diagnostics and treatment. 5.Cutaneousacanthamebiasis. 5.1. Course of disease. 5.2. Diagnostics and treatment. 6. Summary

TAKSONOMIA, WIRULENCJA I CYKLE ŻYCIOWE BACILLUS CEREUS SENSU LATO

Taxonomy, virulence and life cycles of Bacillus cereus sensu lato
Marek Bartoszewicz, Urszula Czyżewska

1. Wstęp. 2. Najważniejsze aspekty biologii B. cereus sensu lato. 2.1. Wyzwanie pierwsze – spójna taksonomia. 2.2. Wyzwanie drugie – cykle życiowe i interakcje z otoczeniem. 2.3. Wyzwanie trzecie – adaptacja do niskich temperatur. 2.4. Wyzwanie czwarte – toksyny B. cereus sensu lato. 3. Podsumowanie

Abstract: Bacillus cereus sensu lato is a group of several species of Gram-positive sporeformers ubiquitous in nature and showing huge impact on human activities. They are often found in soil, air, plant material, animal tissues and digestive tracts as well as in food products. Their genetic similarities and frequent horizontal gene transfer causes doubts regarding their taxonomy. In addition, their toxicity and psychrotolerance constitute serious problems in the dairy industry, being responsible for food-poisonings and spoilage of cold-stored products. Finally, recent finding indicate that B. cereus sensu lato toxicity plays an important role not only in their virulence, but also in social interactions with other bacteria.

1. Introduction. 2. The most important aspects of B. cereus sensu lato biology. 2.1. First challenge – coherent taxonomy. 2.2. Second challenge – life cycles and interactions with the environment. 2.3. Third challenge – adaptation to low temperatures. 2.4. Fourth challenge – toxins of B. cereus sensu lato. 3. Summary

CHARAKTERYSTYKA I POTENCJALNE ZASTOSOWANIE BAKTERIOCYN CYKLICZNYCH

Characteristics and potential applications of circular bacteriocins
Urszula Błaszczyk, Kamila Dąbrowska

1. Charakterystyka i klasyfikacja bakteriocyn cyklicznych. 2. Genetyka bakteriocyn cyklicznych. 3. Biosynteza bakteriocyn cyklicznych. 4. Struktura bakteriocyn cyklicznych. 5. Mechanizmy działania bakteriocyn cyklicznych. 6. Enterocyna AS-48. 7. Potencjalne zastosowanie bakteriocyn cyklicznych. 8. Podsumowanie

Abstract: Bacteriocins are ribosomally synthesized peptides or proteins exerting anatagonistic activity toward organisms which are closely related to the producer strain. Circular bacteriocins are produced by Gram-positive bacteria, mainly lactic acid bacteria, and to a lesser extent by Bacillus, Clostridium and Staphylococcus genera. These bacteriocins are characterized by the head-to-tail cyclization of their backbone. The circular nature of these peptides makes them resistant to many proteolytic enzymes and provides great thermal and pH stability. Circular bacteriocins are divided into 2 subgroups based on their physicochemical properties and sequence identity. These bacteriocins are synthesized as linear precursors with a leader sequence which is cleaved off during maturation. The mature circular peptides are composed of 58–70 amino acid residues. Biosynthesis of circular bacteriocins requires three stages: cleavage of the leader sequence, circularization and export out of the cell. Circular bacteriocins have broad antimicrobial activity spectrum, including many food spoilage bacteria and pathogens, such as Listeria, Staphylococcus and Clostridum spp. Circular bacteriocins permeabilize the membrane of sensitive bacteria, causing loss of ions and dissipation of the membrane potential, and finally cell death. Enterocin AS-48 was the first identified circular bacteriocin and is best characterized so far. Circular bacteriocins or bacteriocin-producing lactic acid bacteria have great potential in food preservation, and possibly in pharmaceutical and cosmetic industries. Thanks to their properties, circular bacteriocins could be an alternative not only to preservatives and methods used to provide microbial food safety presently, but also to less stable, linear bacteriocins.

1. Characteristics and classification of circular bacteriocins. 2. Genetics of circular bacteriocins. 3. Biosynthesis of circular bacteriocins. 4. Structure of circular bacteriocins. 5. Modes of action of circular bacteriocins. 6. Enterocin AS-48. 7. Potential applications of circular bacteriocins. 8. Summary

ZMIANY W TAKSONOMII γ-PROTEOBACTERIA, MODYFIKACJA NAZWY RZĘDU ENTEROBACTERIALES I NOWE RODZINY W OBRĘBIE ENTEROBACTERALES ORD. NOV.

Changes in the taxonomy of γ-Proteobacteria, modification of the order Enterobacteriales and novel families within Enterobacteriales ord. nov.
Paweł Nawrotek, Bartłomiej Grygorcewicz, Adrian Augustyniak

1. Wstęp. 2. Zasady dotyczące wprowadzania zmian taksonomicznych. 3. Przesłanki wprowadzania zmian taksonomicznych. 4. Zmiany w rzędzie Enterobacterales ord. nov. 5. Bazy danych a zmiany w taksonomii rzędu Enterobacterales ord. nov. 6. Podsumowanie

Abstract: Prokaryotic diversity increases every year with each new described species. Since the first discoveries of microorganisms, researchers’ endeavours are dedicated to the systematisation of all known living organisms in a consistent taxonomy. Originally based on morphology, in recent years modern taxonomy develops thanks to the implemenation of new discoveries in the fields of biochemistry and genetics. In the last thirty years, ribotyping was the leading technique used to classify microorganisms. Due to problems with the comparison of certain species, novel methods based on the analysis of proteins have been applied. In-depth analysis of Enterobacteriaceae family showed that its members are more dissimilar than previously thought, which eventually led to dividing this family into seven families and resulted in a change to the name of the order: from Enterobacteriales to Enterobacterales. These changes were applied in some biggest accessible databases. However, there are still many other which have not modified their taxonomy records to date. Such situation may lead to unnecessary confusion, which strengthens the necessity to create one, unified taxonomy which is approved by the whole scientific community.

1. Introduction. 2. Principles regarding the introduction of taxonomical changes. 3. Justification of taxonomical changes. 4. Modifications in the order Enterobacterales ord. nov. 5. Databases and changes in the taxonomy of the order Enterobacterales ord. nov. 6. Summary

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POSTĘPY MIKROBIOLOGII
2017, 56, 4

O Towarzystwie

PTM

Celem Polskiego Towarzystwa
Mikrobiologów jest propagowanie rozwoju nauk mikrobiologicznych

i popularyzowanie osiągnięć
mikrobiologii wśród członków Towarzystwa oraz szerokich kręgów społeczeństwa. Formami działalności jest organizowanie zjazdów, posiedzeń naukowych, kursów, wykładów
i odczytów oraz konkursów prac naukowych; wydawanie i popieranie wydawania czasopism naukowych, książek
i innych publikacji
z dziedziny mikrobiologii; opiniowanie o stanie i potrzebach mikrobiologii polskiej

i występowanie w jej sprawach wobec
władz państwowych; współpraca
z pokrewnymi stowarzyszeniami
w kraju i za granicą.