117,412 research outputs found
Light dazzles from the black box: Whole-cell biosensors are ready to inform on fundamental soil biological processes
No full textWhole-cell biosensors are natural or engineered microorganisms producing signals in response to specific stimuli. This review introduces the use of whole-cell biosensors for the study of the soil system, discuss the recent developments and some current limitations and draws future prospects of the whole-cell biosensors for application to the study of the agro-ecosystems. The review focuses mainly on the lux- and gfp-inserted whole-cell biosensors producing bioluminescence and multicoloured fluorescent proteins, which allow an easy and reproducible detection of the signals from a large number of prokaryotic and eukaryotic soil-borne microorganisms. This review also points out how the whole-cell biosensors indicate the bioavailability of selected analyte, an information that cannot be straight forwardly extrapolated using the chemical methods of soil analysis. However, regardless of the immense progress in biotechnology and genetics that allows to construct whole-cell biosensors for virtually detecting any chemical at ultra low concentrations, the soil still remains the most extreme natural system to be studied with these biotechnological analytical tools. Although a lack of standardization for most of the constructed whole-cell biosensors along with the scarce knowledge of their performance concur to prevent their use in the official methods of soil and environmental analysis, owing to their stability and selectivity we restate that the whole-cell biosensors are ready to provide information on the main processes occurring in soil, and represent unprecedented sensitive tools for improving agriculture and for soil monitorin
Metaproteomics of Soil Microbial Communities
No full textChapter 16 - Metaproteomics of Soil Microbial Communitie
Effects of Biochar on the C Use Efficiency of Soil Microbial Communities: Components and Mechanisms
No full textBiochar production and incorporation into soil is gaining momentum as a sustainable strategy for climate change mitigation, supported by ever increasing reports of significant carbon (C) sequestration in soil and reduction in greenhouse gas (GHG) emissions from the amended soils. With the progression in biochar testing and use, there is also emerging evidence that biochar induces C sequestration in soil, and that it may not be solely caused by its inherent chemical stability, but also by the complex microbially driven processes and an increase in C use efficiency (CUE) through soil microbial metabolism. This evidence contradicts the current paradigm that sees the microbial CUE decrease during the degradation of recalcitrant material due to thermodynamic constraints, as observed only in several short-term and pilot-scale trials. As the CUE in soil results from interactions between several abiotic and biotic factors, in this paper we examine the link between the biochar properties, soil physico-chemical properties and microbial physiology to explain the CUE increase reported for biochar-amended soils. Based on the large body of physico-chemical literature, and on the high functional diversity and metabolic flexibility of soil microbial communities, we hypothesize that the long-term stabilization of biochar-borne C in the soil systems is not only controlled by its inherent recalcitrance, but also by the cooperative actions of improved soil status and increased microbial CUE. Given that the current knowledge on this specific aspect is still poor, in this feature paper we summarize the state of knowledge and examine the potential impact of biochar on some factors contributing to the whole-soil CUE. We conclude that, beside its inherent recalcitrance, biochar weathering and oxidation in soil create physical and chemical conditions that can potentially increase the microbial CUE. While these processes stabilize the microbial processed C in soil and increase soil fertility, more data from long-term field trials are needed to model the relationship between the CUE and the MRT of biochar-borne C. Based on our hypotheses and relying upon analysis of the available literature, we also suggest possible research approaches that may contribute to filling the gaps in the current knowledge on the topic
Activities of proteolytic enzymes
No full textProteases, also known as proteinases or proteolytic enzymes, are a large group of hydrolases that catalyze the cleavage of peptide bonds in proteins to produce peptides and/or amino acids. Classification of proteolytic enzymes is based on three major criteria: type of reaction catalyzed, functional group of the active site, and type of molecular structure and evolutionary relationship among the various enzymes. According to the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology, the proteolytic enzymes can be grouped into proteases and peptidases on the basis of their nature of attack. This chapter describes methods to estimate soil protease activity, utilizing two substrates: casein, essentially a nonspecific substrate, and N-benzoyl-L-argininamide (BAA), a typical substrate for trypsin-like enzyme. The assay is based on colorimetric estimation of products released by the protein and amide-hydrolyzing enzymes when soil is incubated with buffered solutions of casein and BAA, respectively
Nannipieri, P., Ascher, J., Ceccherini, M.T., Landi, L., Pietramellara, G. & Renella, G. 2003. Microbial diversity and soil functions. European Journal of Soil Science, 54, 655–670.: Reflections by P. Nannipieri, J. Ascher-Jenull, M. T. Ceccherini, L. Giagnoni, G. Pietramellara & G. Renella
No full textOur review of 2003 discussed the meaning of both microbial diversity and microbial activity at the dawn of the ‘soil omics’ era. It focused on problems with the methods to determine them and on the main ways that soil functions depend on microbial processes. Between 2003 and 2016, the molecular techniques applied in the study of soil microbial diversity have improved markedly. Sequencing techniques today provide accurate estimates of microbial diversity in soil, whereas determining the expression of microbial genes as synthesized proteins is still problematic (Renella et al., 2014a). The assumption was and still is that with a fuller understanding of microbial diversity we might be able to control some soil functions. This is a fallacy because soil functions depend on microbial activity and not only on microbial diversity. A better understanding of the link between microbial diversity and microbial activity might be obtained by an integration of molecular and classical techniques. Sequencing techniques have confirmed the primary role of soil properties in shaping soil microbial diversity and the redundancy of species involved in soil processes such as the mineralization of organic C. Future research should improve techniques for the characterization of soil proteomics, promote the combination of classical and molecular approaches, promote hypothesis‐ more than technology‐driven research and propose molecular markers as indicators of soil quality, for example, the gene copy/gene expression or gene/enzyme activity ratios
Enzymes activities, detection and expression of genes codyfing enzymes
No full textEnzymes activities, detection and expression of genes codyfing enzymes
Role of Phosphatase Enzymes in Soil
No full textReview sul ruolo dell'attività fosfatasica nel ciclo biogeochimico del fosfor
Cross-tolerance and convergent dependence between morphine and cannabimimetic agent WIN 55,212-2 in the guinea-pig ileum myenteric plexus
No full textNutrizione parenterale in rianimazione. Studio di 190 casi
No full textResults observed in 190 patients receiving parenteral nutrition (including 104 thus treated for periods of 3 to 28 days) are presented. The data point to the importance of both the quantity and quality of the calorie and nitrogen intake. The energy and plastic sources used in the treatment are discussed. The modalities most suited for employment in patients with unimpaired renal functional and in those with serious renal insufficiency are described in the light of personal experience
Bacterial culturability and the viable but non-culturable (VBNC) state studied by a proteomic approach using an artificial soil
No full textGram-negative bacteria in soil rapidly adapt to various stresses, including nutrient limitation and desiccation, by
adopting the viable but non-culturable (VBNC) state as a survival strategy. Due to the physico-chemical and
microbiological complexity of soils, little is understood on the effects of nutrient availability and moisture level
on the transition from the VBNC state to culturability in soil. We evaluated the effects of gluconate or water on
the transition of the soil borne bacterium C. metallidurans strain CH34 from the VBNC state to culturability by
experiments of inoculation into artificial soils and bacterial metaproteomic analysis. Incubation without water or
nutrients reduced the bacterial culturability to zero in 12 d, and addition of both water or gluconate restored the
bacterial culturability to high levels within 24 h. The proteomic analysis showed that under water and nutrient
limitation, proteins related to the cell shape and protein synthesis were rapidly down-regulated and stressrelated
proteins were quickly up-regulated during the transition from culturability to VBNC state. Reversion
from the VBNC state to a culturable state with water or gluconate led to highly different bacterial proteomic
profiles of C. metallidurans. Gluconate availability restored main protein biosynthesis and energy metabolic
pathways, whereas water addition led to up-regulation of only six proteins, one of which degrade sigma factors
involved in expression of genes controlling bacterial resistance under nutrient limitation. Proteins regulated
during the transition between culturable and VBNC states could also be involved in the phenotypic VBNC for
other soil bacteria, and can highlight some of the microbial genetic mechanisms allowing the entering and
exiting from the VBNC state. Implications of the VBNC in microbial diversity and soil functionality are discussed
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