All posts by Postępy Mikrobiologii

Biosorpcja jonów kadmu przez struktury powierzchniowe bakterii z rodzaju Lactobacillus

Biosorption of cadmium ions by cell surface structures of bacteria from Lactobacillus species
M. Michalak, K. Gustaw, A. Waśko, M. Polak-Berecka
6 June 2017

1. Wprowadzenie. 2. Zanieczyszczenie środowiska kadmem a zdrowie człowieka. 3. Bakterie z rodzaju Lactobacillus jako biosorbent jonów metali ciężkich. 4. Rola zewnętrznych struktur komórkowych w wiązaniu jonów metali ciężkich. 4.1. Biosorpcja jonów metali ciężkich przez białka powierzchniowe. 4.2. Udział polisacharydów w wiązaniu jonów metali ciężkich. 5. Czynniki wpływające na wydajność procesu biosorpcji. 6. Kinetyka procesu biosorpcji. 7. Podsumowanie

Biosorption of cadmium ions by cell surface structures of bacteria from Lactobacillus species

Abstract: Cadmium is a heavy metal which is one of the major polluting component of human and animal environment. Exposure can lead to accumulation of metal ions in the tissues, causing adverse health effects. In recent years, the ability of biological material, such as bacteria, to remove cadmium and other toxic metals have been explored. Biosorption is a process of rapid binding of metals from solution onto functional groups that occur on the surface of bacterial cells. Species such as Lactobacillus, present in the human gastrointestinal tract and in fermented food, have the ability to bind and detoxify heavy metal ions due to the occurrence of negatively charged functional groups. These bacteria offer several advantages compared to other microorganisms, primarily thanks to their probiotic activity and GRAS (Generally Recognized As Safe) status. In this review, our intention was to describe the current understanding of biosorption mechanism of lactobacilli and to explain how bacterial surface structures interact with metal ions.

1. Introduction. 2. Environmental pollution by cadmium and human health. 3. Bacteria from Lactobacillus species as biosorbent of heavy metal ions. 4. Role of extracellular structures in the binding of heavy metal ions. 4.1. Biosorption of heavy metal ions by surface proteins. 4.2. Impact of exopolysaccharides on the binding of heavy metal ions. 5. Factors affecting efficiency of biosorption process. 6. Kinetic studies of biosorption process. 7. Summary

Autor: Postępy Mikrobiologii
No Comment
Czytaj dalej

Bakterie kwasu octowego Asaia sp. i ich unikalne zdolności adaptacyjne

Acetic acid bacteria Asaia sp. and their unique adaptive abilities
H. Antolak, D. Kręgiel
6 June 2017

1. Charakterystyka Asaia sp. 2. Zdolności adaptacyjne. 3. Zakażenia oportunistyczne. 4. Symbionta moskitów i walka z malarią. 5. Podsumowanie

Abstract: The natural environment for acetic bacteria of the genus Asaia are Asian fruits, flowers and insects. They are also isolated from spoiled soft drinks in Europe. These bacteria are classified as saprophytes, but there have been some cases of bacteremia caused by Asaia lannensis and A. bogorensis strains. They are also isolated as microbiota of mosquitoes in the tropical climate. Their unique adaptation abilities, such us genes encoding adhesins which help them colonize the environment as well as operons responsible for survival under various conditions, make Asaia sp. potential microorganisms to be used in the fight against malaria.

1. Characteristics of Asaia sp. 2. Adaptability. 3. Opportunistic infections. 4. Mosquito symbionts and the fight against malaria. 5. Summary

Autor: Postępy Mikrobiologii
No Comment
Czytaj dalej

Integrony bakterii Gram-dodatnich

Integrons in Gram-positive bacteria
B. Łabiszak, R. Koczura
6 June 2017

1. Wprowadzenie. 2. Charakterystyka integronów. 3. Integrony bakterii Gram-dodatnich. 3.1. Integrony Corynebacterium spp. 3.2. Integrony Enterococcus spp. 3.3. Integrony Staphylococcus spp. 3.4. Integrony Streptococcus spp. 3.5. Integrony innych gatunków bakterii Gram-dodatnich. 4. Podsumowanie

Abstract: Integrons are genetic platforms responsible for integration, rearrangement and expression of resistance determinants called gene cassettes. Most of the reports on the occurrence, characteristics and evolution of integrons concern Gram-negative bacteria, whereas relatively little is known on the distribution and role of integrons in Gram-positive microorganisms. The aim of this review is to summarize the information about the occurrence of integrons in Gram-positive bacteria and their role in the spread of antimicrobial resistance.

1. Introduction. 2. Integron characteristics. 3. Integrons in Gram-positive bacteria. 3.1. Integrons in Corynebacterium spp. 3.2. Integrons in Enterococcus spp. 3.3. Integrons in Staphylococcus spp. 3.4. Integrons in Streptococcus spp. 3.5. Integrons in other Gram-positive species. 4. Summary

Autor: Postępy Mikrobiologii
No Comment
Czytaj dalej

Genetyczne podłoże oddziaływań bakterii endofitycznych z roślinami

Genetic basis of endophytic bacteria-plant interactions
A. Piński, K. Hupert - Kocurek
6 June 2017

1. Wprowadzenie. 2. Genetyczne uwarunkowania kolonizacji rośliny przez endofity bakteryjne. 3. Genetyczne podłoże odporności bakterii endofitycznych na stres oksydacyjny i osmotyczny. 4. Mechanizmy sekrecji i translokacji białek efektorowych. 5. Czynniki transkrypcyjne zaangażowane w interakcje endofit bakteryjny-gospodarz. 6. Zmiany w ekspresji genów w interakcji endofit bakteryjny-roślina. 7. Podsumowanie

Abstract: Bacterial endophytes promote plant growth through colonization of the internal tissues of the plant without external signs of infection or negative effects on their host. Although endophytic bacteria enter the plant through the primary and lateral root hair cells, root cracks and wounds, they are found at many sites in the plants, such as stems, leaves, seeds, and xylem. The colonization of plant tissues comprises: host recognition, chemotactic migration of endophyte towards root exudates, adhesion to the surface of the root, penetration of the epidermidis and finally adaptation to a new environment. The distinctive features of endophytic bacteria are their flagellar motility, secretion of the cell-wall degrading enzymes (CWDEs) and biofilm-forming ability. It is postulated that endophytic bacteria capable of colonizing plants should contain at least a minimum set of genes responsible for their endophytic behavior. Among them, genes involved in chemotaxis and adhesion processes, secretion and translocation of effector proteins as well as genes which facilitate survival in reactive-oxygen rich environment can be distinguished. An important group of genes are the ones which encode regulatory proteins involved in the control of gene expression at the transcriptional level. However, in establishing an endophytic association with plants, species-specific gene-functions seem to be involved. Identification of genes responsible for endophytic behavior will increase our knowledge about the genetic aspects of plant-endophyte interactions and enable to fully exploit their potential.

1. Introduction. 2. Genetic determinants of plant colonization by bacterial endophytes. 3. The genetic basis of endophytic bacteria resistance to oxidative and osmotic stress. 4. Mechanisms of secretion and translocation of effector proteins. 5. Transcription factors involved in the interactions of bacterial endophytes with the host. 6. Changes in gene expression in the plant-endophyte interactions. 7. Summary

Autor: Postępy Mikrobiologii
No Comment
Czytaj dalej

Rekultywacja gleb skażonych metalami ciężkimi metodą fitostabilizacji wspomaganej

Recultivation of heavy metal-contaminated soils using aided phytostabilization
D. Wasilkowski, A. Mrozik
6 June 2017

1. Wprowadzenie. 2. Strategie tolerancji metali ciężkich u mikroorganizmów i roślin. 3. Koncepcja fitostabilizacji wspomaganej. 4. Aktywność mikrobiologiczna gleby w warunkach fitostabilizacji wspomaganej. 5. Wskaźniki mikrobiologiczne a jakość gleby. 6. Przykłady in situ fitostabilizacji wspomaganej. 7. Podsumowanie

Abstract: The main anthropogenic sources of heavy metals in the environment are mining and smelting, refining and chemical industry, industrial and municipal wastes, transport as well as fertilizers and pesticides used in agriculture. Among all heavy metals, Cd, Cu, Pb, Hg, Ni and Zn are of major environmental and human health concern. The high toxicity of heavy metals causes the need to remove them from the contaminated soil using minimally invasive remediation solutions, called gentle remediation options (GRO). One of the attractive methods to reduce the labile fractions and toxicity of heavy metals in soil seems to be aided phytostabilization. It is a combination of phytostabilization using plants tolerant to trace metals and stabilizing soil against erosion with the initial chemical immobilization achieved by adding various organic and inorganic additives. The potential toxicity of trace elements depends on their specific form present in the environment, their reactivity, mobility, concentration and their availability to living organisms. The bioavailability of heavy metals in soil is constantly changing and depends on different physicochemical, biological and environmental parameters. Due to the fact that microorganisms respond quickly to the presence of stressors in the environment, the changes in metabolic activity, size and structure can be used as good indicators of the effectiveness of applied remediation technology for cleaning up contaminated sites and ecosystem quality.

1. Introduction. 2. Tolerance strategies in microorganisms and plants. 3. Concept of aided phytostabilization. 4. Microbial activity of soil under aided phytostabilization. 5. Microbial indexes and soil quality. 6. Examples of in situ aided phytostabilization. 7. Summary

Autor: Postępy Mikrobiologii
No Comment
Czytaj dalej
1 … 85 86 87 88

Current Issue

Current Issue

Advancements of Microbiology
Volume 63 (2024): Issue 1

Publisher

PTM

Publisher