All posts by Postępy Mikrobiologii

Mikrobiologiczna utylizacja celulozy

Microbial cellulose utilization
K. Poszytek

1. Wprowadzenie. 2. Charakterystyka celulozy. 3. Mikroorganizmy celulolityczne. 4. Enzymy celulolityczne. 4.1. Podział systemów celulolitycznych. 4.2. Zasady funkcjonowania wolnych i skompleksowanych enzymów celulolitycznych. 4.3. Biologia molekularna oraz inżynieria genetyczna celulaz. 5. Ekologiczny i  praktyczny aspekt utylizacji celulozy. 6. Podsumowanie

Abstract: Lignocellulosic biomass, consisting of lignin, cellulose and hemicellulose, can be utilized as a substrate in the production of biofuels. Before application, lignocellulosic material requires preliminary treatment. Biological pretreatment, which can be an alternative to the physical and chemical methods, is based on the activity of microorganisms, mainly bacteria and fungi. They produce cellulolytic enzymes, cellulases, which can effectively degrade lignocellulosic biomass and other materials containing cellulose. At least three major groups of cellulases are involved in the hydrolysis process: endoglucanases, exoglucanases and β-glucosidases. Various types of cellulases exist in a free form or as complexes, known as cellulosomes. In order to increase the activity, cellulolytic enzymes can be modified by means of genetic engineering. The final results are intended to increase the efficiency of hydrolysis of lignocellulosic biomass and thus the process of biochemical changes in the context of biofuel production.

1. Introduction. 2. Characteristics of cellulose. 3. Cellulolytic microorganisms. 4. Cellulolytic enzymes. 4.1. Classification of cellulolytic enzymes. 4.2. Operating principles of free and complexed cellulolytic enzymes. 4.3. Molecular biology and genetic engineering of cellulases. 5. Ecological and practical aspects of cellulose utilization. 6. Summary

Mikroorganizmy w bioaugmentacji zanieczyszczonych środowisk

Microorganisms in bioaugmentation of polluted environments
A. Mrozik

1. Wprowadzenie. 2. Mikroorganizmy w bioaugmentacji. 2.1. Pojedyncze szczepy. 2.2. Konsorcja mikroorganizmów. 2.3. Mikroorganizmy modyfikowane genetycznie. 3. Sposoby dostarczania mikroorganizmów do środowiska. 4. Czynniki ograniczające bioaugmentację. 5. Podsumowanie

Abstract: Bioaugmentation is defined as a technique for improving the degradative capacity of contaminated soil and water by adding selected strains or consortia of microorganisms. In the treatment of environmental pollution by microorganisms, three approaches can be distinguished: autochthonous bioaugmentation, in which microorganisms isolated from contaminated site as an enriched culture are reinjected to the original environment; allochthonous bioaugmentation (bioenrichment), in which seeding material is isolated from another place and gene bioaugmentation, in which genetically engineered microorganisms equipped with genes encoding proteins related to some desired function are introduced into polluted site. In the selection of proper culture for biougmentation, the following features of microorganism should be taken into consideration: fast growth, ease of culivation, capacity to withstand high concentration of contaminants and the ability to survive in a wide range of environmental conditions. The enhancement of bioaugmentation may be also achieved by delivering microorganisms on various carriers or by the use of activated soil. The efficiency of bioaugmentation is determined by abiotic and biotic factors. The first include chemical structure of contaminants, their concentration and bioavailability as well as fluctuations or extremes in temperature, pH and nutrients level. Among biotic factors, the most important are the interactions between autochthonous and added microorganisms such a competition, predation and bacteriophages. Numerous studies have demonstrated that bioaugmentation is a promising technology in remediation of soil, water and sediments polluted with polycyclic aromatic hydrocarbons, nitrophenols, polychlorinated biphenyls, chlorophenols, crude oil, diesel oil and several pesticides.

Introduction. 2. Microorganisms in bioaugmentation. 2.1. Single strains. 2.2. Consortia of microorganisms. 2.3. Genetically engineered microorganisms. 3. Methods for delivering microorganisms into environment. 4. Factors limiting bioaugmentation. 5. Summary

Bakteriocyny bakterii Gram-ujemnych – struktura, mechanizm działania i zastosowanie

Bacteriocins of Gram-negative bacteria – structure, mode of action and potential applications
U. Błaszczyk, J. Moczarny

1. Wprowadzenie. 2. Klasyfikacja bakteriocyn bakterii Gram-ujemnych. 3. Produkcja kolicyn przez bakterie kolicynogenne. 3.1. Synteza kolicyn. 3.2. Eksport kolicyn z komórek producenta. 4. Mechanizmy działania kolicyn. 4.1. Translokacja. 4.2. Efekt letalny kolicyn. 5. Charakterystyka i podział mikrocyn. 5.1. Struktura i genetyka wybranych mikrocyn. 5.1.1. MccE492. 5.1.2. MccJ25. 5.1.3. MccC7-C51. 5.2. Mechanizmy działania mikrocyn. 5.2.1. MccE492. 5.2.2. MccJ25. 5.2.3. MccC7-C51. 6. Potencjalne zastosowanie kolicyn i mikrocyn. 7. Podsumowanie

Abstract: Bacteriocins are a diverse group of ribosomally synthesized peptides or proteins secreted by bacteria, which help them to compete in their local environments for the limited nutritional resources. Bacteriocins kill or inhibit the growth of other bacteria. Generally, these molecules have a narrow spectrum of antibacterial activity, but some of them demonstrate a broad spectrum of action. Bacteriocins from Gram-negative bacteria are divided into two main groups: high molecular mass proteins (30–80 kDa) known as colicins, and low molecular mass peptides (between 1–10 kDa) termed microcins. Colicins are produced by Escherichia coli strains harbouring a colicinogenic plasmid. Such colicinogenic strains are widespread in nature and are especially abundant in the gut of animals. The biosynthesis of colicins is mediated by the SOS regulon, which becomes activated in the response to DNA damage. The colicin synthesis is lethal for the producing cells as a consequence of the concomitant biosynthesis of the colicin lysis protein. Microcins are usually highly stable molecules, which are resistant to proteases, extreme pH values and temperatures. They are produced by enteric bacteria under stress conditions, particularly nutrient depletion. Microcins are encoded by gene clusters carried by plasmids or in certain cases by the chromosome. In this review, we have summarized the most important information about structure and properties of bacteriocins from Gram-negative bacteria, their diverse mechanisms of action and potential application as food preservatives and in livestock industry.

1. Introduction. 2. Classification of bacteriocins from Gram-negative bacteria. 3. Production of colicins by colicinogenic bacteria. 3.1. Colicin synthesis. 3.2.  Export of colicins from bacteriocin-producing cells. 4. Modes of colicin action. 4.1. Translocation. 4.2. Lethal effect of colicins. 5. Characteristics and classification of microcins. 5.1. Structure and genetics of selected microcins. 5.1.1. MccE492. 5.1.2. MccJ25. 5.1.3. MccC7-C51. 5.2. Mechanisms of action of microcins. 5.2.1. MccE492. 5.2.2. MccJ25. 5.2.3. MccC7-C51. 6. Potential applications of colicins and microcins. 7. Summary

Skuteczność wykorzystania niskotemperaturowej plazmy w mikrobiologii i medycynie

Efficiency of using non-thermal plasma in microbiology and medicine
M. Laskowska, E. Bogusławska-Wąs, P. Kowal, M. Hołub, W. Dąbrowski

1. Wstęp. 2. Mechanizm działania zimnej plazmy na mikroorganizmy. 2.1. Efektywność działania sterylizującego. 3. Zastosowanie zimnej plazmy w medycynie. 4. Podsumowanie

Abstract: Plasma is a partially or totally ionized gas which occurs in nature (e.g. lightning discharge, outer space), but can be also created in the laboratory conditions. Non-thermal plasma generates free radicals of oxygen, nitrogen, high energy electrons and uncharged particles such as atoms and molecules, in aquatic and gas environment. Thus, plasma exerts its effect on both prokaryotic and eukaryotic cells. In many studies, non-thermal plasma was applied mainly to achieve the sterilization effects of e.g. surfaces and medical tools. The results obtained were largely dependent upon the applied parameters of plasma (e.g. frequency, voltage, type of gas). Non-thermal plasma can be applied in microbiology and also in medicine where it can be used to speed up wound healing process or as an effective tool in oncology.

1. Introduction. 2. Plasma action on microorganisms. 2.1. Sterilization efficiency. 3. Application of cold plasma in medicine. 4. Summary

Drobnoustroje radiotolerancyjne – charakterystyka wybranych gatunków oraz ich potencjalne zastosowanie

Radiotolerant microorganisms – characterization of selected species and their potential usage
D. M. Matusiak

1. Wprowadzenie. 1.1. Promieniowanie oraz jego wpływ na organizmy żywe. 1.2. Drobnoustroje radiotolerancyjne – definicja, teorie na temat pochodzenia, oporność na promieniowanie. 2. Charakterystyka wybranych organizmów radiotolerancyjnych. 2.1. Bakterie. 2.2. Archeony. 2.3. Grzyby mikroskopowe. 3. Podsumowanie

Abstract: Ionizing radiation damages DNA, proteins and lipids in cells in a direct (10–20% DNA damage) and indirect manner (80–90%) – causing water radiolysis and a redox potential increase (oxido-reductive stress). For instance, hydrogen peroxide and ozone are generated. Hydroxyl radical (OH.) is the most reactive and harmful reactive oxygen species (ROS). Radiotolerant microorganisms are extremophilic microbiota, sustaining high doses of radiation in a vegetative state. One of the most resistant and extensively studied species is Deinococcus radiodurans. This bacterium can reconstitute its genome shattered to dozens of fragments (double strand breaks) as a result of the exposure to radiation or dessication. Other examples include: bacteria: Acinetobacter radioresistens, Rubrobacter radiotolerans, Kineococcus radiotolerans, Ralstonia sp. and Burkholderia sp. (living in biofilm communities from spent fuel pools); archaea: Thermococcus gammatolerans; diverse microscopic, often melanized, presumably radiotropic fungi, e.g. Cladosporium spp., from the surrounding of the destroyed Chernobyl power plant. Many of such organisms can be found in desert areas as they are dehydratation-tolerant. Radioresistant species can be potentially utilized for bioremediation of radioactive environment contamination and for nuclear waste management (e.g. bioprecipitation, biosorption, bioaccumulation of uranium or other radioisotopes). For example, diverse molds isolated from the Chernobyl region can be used for mycoremediation due to their ability to decompose contaminated organic matter, adsorb, converse into a soluble form and accumulate radionuclides (e.g. caesium 137).

1. Introduction. 1.1. Radiation and its effect on organisms. 1.2. Radiotolerant microorganism – definition, theories about their origin, radioresistance. 2. Description of selected radiotolerant species 2.1. Bacteria. 2.2. Archaea. 2.3. Microfungi. 3. Summary

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POSTĘPY MIKROBIOLOGII
2018, 57, 1

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.