All posts by Postępy Mikrobiologii

Bakterie endofityczne – ich pochodzenie i interakcje z roślinami

Bacterial endophytes – their origin and interaction with plants
K. Pisarska, S. J. Pietr
10 August 2017

1. Wstęp. 2. Źródła bakterii endofitycznych. 3. Kolonizacja rośliny – gospodarza przez bakterie endofityczne. 4. Oddziaływania molekularne. 5. Znaczenie bakterii endofitycznych dla roślin. 6. Endofity jako potencjalne patogeny i inhibitory wzrostu roślin 7. Podsumowanie

Abstract: Endophytic bacteria colonize tissue of healthy plants. The source of these bacteria are plant seedlings, seeds and soil. The impact of these microorganisms on plants have been tested for biological control of pathogens, induction of systemic resistance, promote growth and development of plants through binding of free nitrogen, increase in minerals uptake and increase plant resistance to unfavorable abiotic factors. The most numerous reported taxa of endophytic bacteria belong to the genues of phyla Proteobacteria (Azospirillum, Enterobacter, Erwinia, Pantoea, Pseudomonas), Bacteroidetes (Flavobacterium) and Firmicutes (Bacillus).
Endophytes show a great potential in plant production. Increasing interest in these microorganisms in plants protection seems to be an essential part of sustainable crop production. Indeed, their use may bring benefits for agriculture, including increased efficiency of mineral fertilizer, reduce agricultural production costs through more efficient use of fertilizers as well as reduced application of synthetic pesticides. Adoption of microbes will also reduce negative impact of crop production on environment. To avoid potential human pathogens in plant protection, microbes have to undergo a comprehensive risk assessment. In the EU, this assessment is based on principles which were originally developed for pesticides. Although the EU directive concerning the registration of microorganisms as Biological Control Agents, has been adapted to better understand the requirements of microorganisms, it is still time consuming and require large financial input. In EU countries, registration of BCAs lasts up to 7 years, which discourages this type of research and keeps safer plant protection products off the market.

1. Introduction. 2. Sources of endophytic bacteria. 3. Plant colonization 4. Molecular interactions. 5. Effects of endophytic bacteria to the plant. 6. Bacterial endophytes like a potential pathogens and plant growth inhibitors 7. Conlusions

Autor: Postępy Mikrobiologii
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Plastyczność bakteryjnych genomów – wewnątrzkomórkowy transfer genów

Bacterial genome plasticity – intracellular transfer of genetic information
U. Kasprzykowska, B. M. Sobieszczańska
10 August 2017

1. Wstęp. 2. Mobilne elementy genetyczne. 3. Sekwencje insercyjne i transpozony. 4. Integrony i kasety genowe. 5. Integracyjne elementy koniugacyjne/integrony koniugacyjne. 6. Wyspy patogenności. 7. Podsumowanie

Abstract: Bacterial genomes constantly evolve upon selective pressure of an environmental factors. Mechanisms that play a role in the genome plasticity include mutations, DNA rearrangements and horizontal gene transfer. Mobile genetic elements are potent agents of bacterial evolution as they exhibit intracellular and intercellular mobility. They may be excluded from one locus and integrated elsewhere in the chromosome. Before integration some acquired genetic elements undergo replicative transposition or are transferred horizontally by transduction, natural transformation or conjugative transfer. In this review, we described the various mobile genetic elements that have an impact on bacterial genome plasticity and microbial evolution with a focus on their intracellular mobility.

1. Introduction. 2. Mobile genetic elements. 3. Insertion sequences and transposons. 4. Integrons and gene cassettes. 5. Integrative and conjugative elements. 6. Pathogenicity associated islands. 7. Summary

Autor: Postępy Mikrobiologii
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Plastyczność bakteryjnych genomów – międzykomórkowy transfer informacji genetycznej

Bacterial genome plasticity – intercellular transfer of genetic information
U. Kasprzykowska, B. M. Sobieszczańska
10 August 2017

1. Wstęp. 2. Transdukcja – bakteriofagi. 3. Koniugacja i plazmidy. 4. Transformacja. 5. Podsumowanie

Abstract: Mutations in the bacterial genomes are responsible for minor genetic changes. Most extensive restructuring of bacterial genomes arise from inter- and intragenetic gene transfer. Multiple types of transposition elements responsible for movement of DNA within cells have been described. All these transposable elements may outreach other cells of the same bacterial species or bacteria of another species via transduction, conjugation and transformation. These three mechanisms of horizontal gene transfer have a great impact on evolution of prokaryotic organisms by allowing molecular innovations to spread among bacteria and promote their adaptation to a new environments. On the other hand, horizontal gene transfer also enables bacteria to adapt to the host both, by spreading virulence determinants and allowing pathogens to acquire genes of resistance to many antimicrobials. This review presents phenomenons of transduction, conjugation and transformation, as three distinct mechanisms of intercellular DNA transfer that provide potential evolutionary advantage to prokaryotes.

1. Introduction. 2. Transduction – bacteriophages. 3. Conjugation and plasmids. 4. Transformation. 5.Summary.

Autor: Postępy Mikrobiologii
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Zakażenia układu moczowego z udziałem Proteus mirabilis – rola biofilmu i inkrustacji cewnika urologicznego

Urinary tract infections caused by Proteus mirabilis – role of the biofilm and the encrustation of the urological catheter
D. M. Matusiak
10 August 2017

1. Zakażenia układu moczowego. 2. Proteus mirabilis – charakterystyka ogólna. 3. Biofilm – definicja, opis. 4. Biofilm na cewniku urologicznym i jego inkrustacja. 5. Zapobieganie i leczenie CAUTI u osób poddanych cewnikowaniu. 6. Podsumowanie

Abstract: Urinary tract infection (UTI) is one of the most common nosocomial infections. Proteus mirabilis is important Gram-negative, dimorphic and motile pathogen (Enterobacteriaceae family), causing UTI – especially in catheterized patients. Key elements leading to CAUTI are: catheter colonization, mono- or multi-species biofilm formation and the long period of the catherization. Biofilm is microorganisms’ protective and dynamic community, attached to surface and embedded in extracellular matrix (mainly polysaccharides). P. mirabilis can easily adhere to catheter surface and cause it’s encrustation and blockage (due to urine alkalization by urease, leading to struvite and apatite crystals precipitation). Struvite contains magnesium ammonium phosphate and apatite – calcium phosphate. Urine flow obstruction can elicit pyelonephritis. Other uropathogens, producing urease e.g. Morganella morganii, Providencia stuartii, Escherichia coli (some strains), Klebsiella pneumoniae rather rarely cause catheter blockage. There have been proposed many solutions, preventing catheter biofilm colonization or disrupting formed consortium. However by this time there is no high-effective and broadly used remedy. One of the solutions is the impregnation of the catheters with silver, EDTA, antiseptics (e.g. triclosan, chlorohexidine), antibiotics, heparin or lactoferrin – short-term and insufficient-concentration release, risk of the resistance onset, sometimes non-wide spectrum activity. This solutions are generally moderately effective and postpones the emergence of bacteruria. Another approach (experimental) for example is to inhibit urease or the quorum sensing. The surface of the catheter also could be more hydrophilic and smooth, to inhibit the bacterial attachment.

1. Urinary tract infections. 2. Proteus mirabilis – general description. 3. Biofilm – definition, characterization. 4. Biofilm on urinary catheter and it’s encrustation. 5. Prophylaxis and treatment of CAUTI in catheterized patients. 6. Summary

Autor: Postępy Mikrobiologii
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Metody wykorzystywane w ocenie oddziaływania odpadów organicznych na aktywność mikrobiologiczną gleby

Methods used in the evaluation of the organic wastes influence on soil microbial activity
A. Kot, M. Frąc
10 August 2017

1. Wprowadzenie. 2. Odpady organiczne. 3. Aktywność enzymatyczna 4. Analiza profilu metabolicznego (CLPP – Community Level Physiological Profiles). 5. Badania różnorodności mikroorganizmów oparte na metodzie molekularnej PCR-DGGE. 6. Podsumowanie

Abstract: Organic wastes are useful in agriculture as organic and nutrients fertilizers. Changes in soil environment after application of organic wastes may be successfully controlled using conventional and molecular methods. Microorganisms play important role in soil organic matter transformations. Evaluation of their enzymatic activity, functional and genetic diversity can be used as sensitive tool to asses soil quality and fertility. It is important to combine conventional microbiological methods with molecular techniques, to obtain more information about population of soil microbiota.

1. Introduction. 2. Organic wastes. 3. Enzymatic activity 4. Community Level Physiological Profiles – CLPP. 5. Research of microbial diversity based on PCR-DGGE molecular method. 6. 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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