Browsing tag: gleba

Glomalina – glicoproteina glebowa produkowana przez grzyby mykoryzy arbuskularnej

Glomalin – soil glicoprotein produced by arbuscular mycorhizal fungus
A. Gałązka, K. Gawryjołek

1. Wprowadzenie. 2. Arbuskularne grzyby mykoryzowe. 3. Budowa i właściwości glomalin. 4. Produkcja i rozkład glomalin. 5. Występowanie glomalin. 6. Terminologia i metodyka oznaczeń. 7. Funkcje glomalin. 8. Czynniki wpływające na spadek produkcji glomalin. 9. Podsumowanie

Abstract: Glomalin is hydrophobic glycoprotein produced by arbuscular mycorhizal fungi (AMF). AMF can excrete glomalin into the soil. Glomalin is an abundant soil protein that could sequester substantial amounts of carbonand natrium on a global scale. It has a positive influence on soil structure by increasing aggregate stability of soil, which correlates linearly with the amount of detected glomalin. Glomalin production has an impact on many environmental factors including soil condition. Its content in soil is dependent on both the types of plants and fungal symbiotic species. Glomalins are especially resistant to destruction and hard to dissolve in water. Their extraction from the soil requires specific conditions: high temperature (121°C) and citrate buffer with neutral or alkaline pH. These properties make glomalins very stable compounds that create a perfect protective “jacket” for soil aggregates against degradation. However, they are also difficult to understand and determining their exact construction is still a challenge.

1. Introduction. 2. Arbuscular mycorhizal fungus. 3. Structure and properties of glomalin. 4. Production and decomposition of glomalin. 5. Origins of glomalin. 6. Terminology and methods. 7. Role of glomalin. 8. Factors affecting glomalin production. 9. Summary

Oddziaływanie fungicydów na mikroorganizmy w środowisku glebowym

The impact of fungicides on soil microorganisms
S. Sułowicz, Z. Piotrowska-Seget

1. Charakterystyka fungicydów. 2. Wpływ presji fungicydowej na ekosystem glebowy. 3. Oddziaływanie fungicydów na mikroorganizmy glebowe. 4. Triazole – charakterystyka i wpływ na ekosystem glebowy. 5. Podsumowanie

Abstract: Modern agriculture depends heavily on pesticides, including fungicides. Fungicides such as triazoles, when applied every year, may accumulate in soils leading to the development of resistance to the applied compounds and subsequently to the spread of resistance genes to other fungi. Additionally, fungicides can impact non-target soil microorganisms by reducing their biomass, changing microbial activity, and altering functional and structural diversity of bacterial and fungal communities. Soil quality is closely linked to the microbial activity, therefore, the effects of fungicides on non-target soil microorganisms increase concerns about the fertility of soil. This new knowledge about specific interaction between fungicides and soil microorganisms has to be taken into consideration in designing a new strategy for soil protection.

1. Fungicides. 2. The influence of fungicide pressure on soil ecosystem. 3. The impact of fungicides on soil microorganisms. 4. Triazoles – their characteristic features and influence on soil ecosystem. 5. Conclusions

Krezole a drobnoustroje środowiska glebowego

Cresols and the microorganisms of the soil environment
M. Zaborowska

1. Wstęp. 2. Naturalne i antropogeniczne źródła krezoli w środowisku. 3. Toksyczność krezoli. 4. Drobnoustroje uczestniczące w rozkładzie krezoli. 5. Tlenowy katabolizm krezoli. 6. Beztlenowy katabolizm krezoli. 7. Mikrobiologiczna degradacja krezoli w środowisku glebowym. 8. Podsumowanie

Abstract: Phenolic compounds, including cresols, in the soil environment are a result of natural processes such as: biodegradation of lignins and tannins, and anthropogenic activity. Cresols are present in disinfectants as well as in the wastewater from chemical, petrochemical, pharmaceutical, paper and textile industry. They are also used in the production of insecticides, herbicides, medicines and antioxidants and have been classified as hazardous substances. Exposure of microorganisms to cresols can bring about changes in the structure of their cell membranes, resulting in their growth inhibition and cell lysis. However, there is still an untapped bioremediation potential in microorganisms, which are able to participate in the catabolism of cresols, both under aerobic and anaerobic conditions. The typical strategies of the aerobic degradation of cresols include the use of monooxygenase and dioxygenase enzymes. Thanks to these enzymes, atoms of molecular oxygen initiate fission of the aromatic ring structure. Under anaerobic conditions, the mechanisms of cresol decomposition  currently focus on the addition of fumarate, hydroxylation or carboxylation. The effectiveness of microorganisms in the degradation of cresols is not only due to their occurrence in consortia. They are also effective as single strains. The only controversial aspect involves using genetically modified organisms (GMOs) or their genes in the bioaugmentation process. This is because they are strictly selected and target only specific substrates. Due to this, they do not compete with autochthonous microorganisms undergoing natural selection.

1. Introduction. 2. Natural and anthropogenic sources of cresols in the environment. 3. Toxicity of cresols. 4. The microorganisms participating in the distribution of cresols. 5. Aerobic catabolism of cresols. 6. Anaerobic catabolism of cresols. 7. Microbial degradation of cresols in the soil environment. 8. Summary

Rekultywacja gleb skażonych metalami ciężkimi metodą fitostabilizacji wspomaganej

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

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