Antibiotic resistance represents one of the greatest threats to global health. The spread of anti... more Antibiotic resistance represents one of the greatest threats to global health. The spread of antibiotic resistance genes among bacteria occurs mostly through horizontal gene transfer via conjugation mediated by plasmids. This process implies a direct contact between a donor and a recipient bacterium which acquires the antibiotic resistance genes encoded by the plasmid and, concomitantly, the capacity to transfer the acquired plasmid to a new recipient. Classical assays for the measurement of plasmid transfer frequency (i.e., conjugation frequency) are often characterized by a high variability and, hence, they require many biological and technical replicates to reduce such variability and the accompanying uncertainty. In addition, classical conjugation assays are commonly tedious and time-consuming because they typically involve counting colonies on a large number of plates for the quantification of donors, recipients, and transconjugants (i.e., the bacteria that have received the ge...
Soils of abandoned and vacant lands in the periphery of cities are frequently subjected to illega... more Soils of abandoned and vacant lands in the periphery of cities are frequently subjected to illegal dumping and can undergo degradation processes such as depletion of organic matter and nutrients, reduced biodiversity, and the presence of contaminants, which may exert an intense abiotic stress on biological communities. Mycorrhizal-assisted phytoremediation and intercropping strategies are highly suitable options for remediation of these sites. A two-year field experiment was conducted at a peri-urban site contaminated with petroleum hydrocarbons and polychlorinated biphenyls, to assess the effects of plant growth (spontaneous plant species, Medicago sativa, and Populus × canadensis, alone vs. intercropped) and inoculation of a commercial arbuscular mycorrhizal and ectomycorrhizal inoculum. Contaminant degradation, plant performance, and biodiversity, as well as a variety of microbial indicators of soil health (microbial biomass, activity, and diversity parameters) were determined. T...
Bacterial resistance to antibiotics poses enormous health and economic burdens to our society, an... more Bacterial resistance to antibiotics poses enormous health and economic burdens to our society, and it is of the essence to explore old and new ways to deal with these problems. Here we review the current status of multi-resistance genes and how they spread among bacteria. We discuss strategies to deal with resistant bacteria, namely the search for new targets and the use of inhibitors of protein-protein interactions, fragment-based methods, or modified antisense RNAs. Finally, we discuss integrated approaches that consider bacterial populations and their niches, as well as the role of global regulators that activate and/or repress the expression of multiple genes in fluctuating environments and, therefore, enable resistant bacteria to colonize new niches. Understanding how the global regulatory circuits work is, probably, the best way to tackle bacterial resistance.
The long-term impact of sewage sludge application on agricultural soil was studied. • We observed... more The long-term impact of sewage sludge application on agricultural soil was studied. • We observed Cu and Zn accumulation in soil, but without increased bioavailability. • We found correlation between soil Cu and Zn concentration and antibiotic resistance. • The composition of soil prokaryotic communities was not significantly altered. • The abundance of some antibiotic resistance genes increased in amended soils.
The application of nanoscale zero-valent iron particles (nZVI) for the remediation of contaminate... more The application of nanoscale zero-valent iron particles (nZVI) for the remediation of contaminated sites is very promising. However, information concerning the ecotoxicity of nZVI on soil microbial communities and, hence, soil quality, is still scarce. We carried out a three-month experiment to evaluate the impact of the application of different concentrations of nZVI (from 1 to 20 mg nZVI g DW soil-1) on soil microbial properties in a clay-loam versus a sandy-loam soil. Data on microbial biomass (total bacteria and fungi by qPCR, microbial biomass carbon), activity (β-glucosidase, arylsulphatase and urease activities), and functional (Biolog Ecoplates TM) and structural (ARISA, 16S rRNA amplicon sequencing) diversity evidenced that the sandy-loam soil was more vulnerable to the presence of nZVI than the clay-loam soil. In the sandy-loam soil, arylsulphatase activity and bacterial abundance, richness and diversity were susceptible to the presence of nZVI. The high content of clay and organic matter present in the clay-loam soil may explain the observed negligible effects of nZVI on soil microbial properties. It was concluded that the impact of nZVI on soil microbial communities and, hence, soil quality, is soil dependent.
Materials science & engineering. C, Materials for biological applications, 2015
Microbial growth on medical and technical devices is a big health issue, particularly when microo... more Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited the growth of the nosocomial pathogens Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by the growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced the growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, wh...
We studied the effectiveness of remediation on microbial endpoints, namely microbial biomass and ... more We studied the effectiveness of remediation on microbial endpoints, namely microbial biomass and activity, microbial and plant species richness, of an As-contaminated mine spoil, amended with compost (C) alone and in combination with beringite (B) or zerovalent iron grit (Z), to increase organic matter content and reduce trace elements mobility, and to allow Holcus lanatus and Pinus pinaster growth. Untreated spoil showed the lowest microbial biomass and activity and hydrolase activities, and H. lanatus as sole plant species, whereas the presented aided phytostabilisation option, especially CBZ treatment, significantly increased microbial biomass and activity and allowed colonisation by several plant species, comparable to those of an uncontaminated sandy soil. Microbial species richness was only increased in spoils amended with C alone. No clear correlation occurred between trace element mobility and microbial parameters and plant species richness. Our results indicate that the choice of indicators of soil remediation practices is a bottleneck.
Staphylococcus epidermidis has emerged as one of the major nosocomial pathogens associated with i... more Staphylococcus epidermidis has emerged as one of the major nosocomial pathogens associated with infections of implanted medical devices. The most important factor in the pathogenesis of these infections is the formation of bacterial biofilms. Bacteria grown in biofilms are more resistant to antibiotics and to the immune defence system than planktonic bacteria. In these infections, the antimicrobial therapy usually fails and the removal of the biofilm-coated implanted device is the only effective solution. In this study, three proteomic approaches were performed to investigate membrane proteins associated to biofilm formation: (i) sample fractionation by gel electrophoresis, followed by isotopic labelling and LC-MS/MS analysis, (ii) in-solution sample preparation, followed by isotopic labelling and LC-MS/MS analysis and (iii) in-solution sample preparation and label-free LC-MS/MS analysis. We found that the commensal strain S. epidermidis CECT 231 grown in biofilms expressed higher levels of five membrane and membrane-associated proteins involved in pathogenesis: accumulation-associated protein, staphylococcal secretory antigen, signal transduction protein TRAP, ribonuclease Y and phenol soluble modulin beta 1 when compared with bacteria grown under planktonic conditions. These results indicate that a commensal strain can acquire a pathogenic phenotype depending on the mode of growth.
EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria, 2020
Antibiotikoen aurkako erresistentzia duten bakterioak mundu mailako osasun arriskua dira gaur egu... more Antibiotikoen aurkako erresistentzia duten bakterioak mundu mailako osasun arriskua dira gaur egun infekzioak tratatzeko ditugun terapien eraginkortasunaren galera ekar dezaketelako. Mehatxu horri aurre egiteko modu bat eskuartean ditugun farmakoak garraio sistema egokietan txertatzea izan daiteke eraginkortasunaren hobekuntza eta erresistentzien agerpenaren atzeratzea ekar dezaketelako. Farmakoen garraio sistema ezberdinen artean Lipido Solidozko Nanopartikulek ezaugarri ezin hobeak eskaintzen dituzte farmakoen solugarritasuna, iragazkortasuna, askapen-zinetika eta egonkortasuna bezalako ezaugarri garrantzitsuak hobetzeaz gain toxizitatea murrizten laguntzen dutelako. Lipido Solidozko Nanopartikulak nukleo lipidiko solido bat eta emultsionatzaile geruza batez osaturiko nanopartikulak dira, konposatu fisiologikoekin osatzen direnak. Dena den, farmakoen garraio sistema efizienteen garapenak nanopartikula eta sistema biologikoen arteko elkarrekintzen ezaguera eskatzen du eta horretara...
Current topics in microbiology and immunology, 2017
Type IV coupling proteins (T4CPs) are essential constituents of most type IV secretion systems (T... more Type IV coupling proteins (T4CPs) are essential constituents of most type IV secretion systems (T4SSs), and probably the most intriguing component in terms of their evolutionary origen and functional role. Coupling proteins have coevolved with their cognate secretion system and translocated substrates. They are present in all conjugative systems, leading to the suggestion that they play a specific role in DNA transfer. However, they are also part of many T4SSs involved in bacterial virulence, where they are required for protein translocation, with no apparent involvement in DNA secretion. Their name reflects genetic and biochemical evidence of a connecting role between the substrate and the T4SS, thus probably playing a major role in substrate recruitment. Increasing evidence supports also a role in signal transmission leading to activation of secretion. Most studies have addressed conjugative coupling proteins of the VirD4-like protein family. Their conserved features include a nuc...
The increasing rates of antimicrobial resistance among carbapenem-resistant Acinetobacter baumann... more The increasing rates of antimicrobial resistance among carbapenem-resistant Acinetobacter baumannii in the Middle East and North Africa are one of the major concerns for healthcare settings. We characterised the first A. baumannii isolate harbouring five β-lactamases identified in Egypt. The isolate Ale25 was obtained from an ICU patient of a hospital from Alexandria. The isolate was phenotypically and genotypically screened for carbapenemase genes. The isolate was resistant to carbapenems, aminoglycosides, fluoroquinolones and cefiderocol. Whole-Genome Sequencing identified five β-lactamase genes, blaNDM-1, blaOXA-23, blaOXA-64, blaPER-7 and blaADC-57, together with other antibiotic resistance genes, conferring resistance to sulfonamides, macrolides, tetracyclines, rifamycin and chloramphenicol. Virulome analysis showed the presence of genes involved in adhesion and biofilm production, type II and VI secretion systems, exotoxins, etc. Multi-Locus Sequence Typing analysis identified...
Additional Figure 1. Flowsheet of the bacterial P3HB production process in Scenario 1. Green: the... more Additional Figure 1. Flowsheet of the bacterial P3HB production process in Scenario 1. Green: thermo-chemical pre-treatment and enzymatic hydrolysis. Blue: bacterial process. Orange: extraction-separation.
Rapid urbanization followed by economic crisis frequently results in the presence of degraded aba... more Rapid urbanization followed by economic crisis frequently results in the presence of degraded abandoned urban plots inside or in the periphery of cities. Urban greening can be a low-cost solution for their reclamation but, inevitably, the necessary plants require an appropriate medium to grow and thrive. In this study, Technosols were explored as a suitable option to simultaneously face two common challenges of many cities, i.e., the reclamation of degraded abandoned city plots and the recycling of industrial and urban wastes. To this purpose, a mesocosm experiment was carried out to assess the suitability of six different Technosols (resulting from the combination of the following four ingredients: CDW: construction and demolition wastes; BIO: bio-stabilized material from a municipal composting plant; BENT: recycled bentonites from a local industry; TS: topsoil from vacant public plots) for the reclamation of abandoned city plots. The six Technosols were prepared in triplicate and then installed in 12 m 2 experimental cells. Control cells
Organic amendments are being increasingly applied to agricultural soils as alternatives or comple... more Organic amendments are being increasingly applied to agricultural soils as alternatives or complements to inorganic fertilizers. Organic amendments can increase the content of soil organic matter, concomitantly improving soil physical, chemical and biological properties. We evaluated the effect of the application of commercial vs. farm-made fermented liquid organic amendments, compared to mineral (NPK) fertilization, on corn yield and nutritional status, as well as on soil physicochemical and microbial properties as indicators of soil quality. In particular, we assessed the effect of two doses (optimal vs. suboptimal) and times of amendment application (basal dressing vs. basal + top dressing) for two consecutive growing seasons. Values of corn grain yield were lower in organically-amended plots than in those under NPK fertilization. At the optimal dose, the application of organic amendments led to significantly higher values of microbial activity (soil respiration; enzyme activities; potentially mineralizable N) and biomass (microbial biomass C, bacterial and fungal biomass), leading to an improvement in soil quality. The optimal application dose resulted in an enhanced soil nutrient pool. Conversely, soil properties were not significantly affected by the origen of the amendment (commercial vs. farm-made) or the time of application (basal dressing vs. basal + top dressing). 16S rRNA metabarcoding analysis revealed no significant changes in the diversity and composition of the soil prokaryotic communities between organically-amended and NPK-fertilized soils. It was concluded that the application of fermented liquid organic amendments at the optimal dose (according to the N requirements of corn) can be a beneficial agronomic practice for agricultural soil quality, posing a suitable alternative to mineral fertilization.
The anaerobic decomposition of organic wastes might lead to the formation of organic-byproducts w... more The anaerobic decomposition of organic wastes might lead to the formation of organic-byproducts which can then be successfully used as organic fertilizers. This study evaluated the impact of the application of two fermented liquid organic amendments (commercial vs. farm-made) at two doses of application (optimal vs. suboptimal), compared to mineral fertilization, on lettuce growth and soil quality. To this purpose, two experiments were conducted at microcosm-and field-scale, respectively. In the microcosm experiment, organically amended soils resulted in lower lettuce yield than minerally fertilized soil but, in contrast, they enhanced microbial activity and biomass, thus leading to an improvement in soil quality. The fertilization regime (organic vs. inorganic) significantly affected soil microbial composition but did not have any significant effect on structural or functional prokaryotic diversity. In the field experiment, at the optimal dose of application, organically-amended soils resulted in comparable lettuce yield to that displayed by minerally fertilized soils. The application of organic amendments did not result in an enhanced microbial activity and biomass, compared to mineral fertilization, but led to a higher soil prokaryotic diversity. Among the organically-amended plots, the optimal application dose resulted in a higher lettuce yield and soil microbial activity and biomass, but led to a decline in soil prokaryotic diversity, compared to the suboptimal application dose. Our results indicate that commercial and farm-made fermented liquid organic amendments possess the potential to ameliorate soil quality while sustaining crop yield. Given the strong influence of other factors (e.g., type of soil, dose of application) on the effects exerted by such amendments on soil quality and fertility, we recommend that an exhaustive characterization of both the amendments and the recipient soils should be carried out prior to their application, in order to better ensure their potential beneficial effects.
An extracellular pectin lyase (PNL) [poly-(methoxygalacturonide)lyase; EC 4.2.2.10] produced by P... more An extracellular pectin lyase (PNL) [poly-(methoxygalacturonide)lyase; EC 4.2.2.10] produced by Penicillium italicum CECT 2294 grown on a surface bran (natural medium) or in a submerged (synthetic medium) culture was investigated. Both culture filtrates showed macerating activity at low pH on cucumber, potato, and orange tissues. The physicochemical properties of the enzyme obtained from both culture methods were identical, as well as its catalytic properties, which were assayed by different methods. The molecular mass of the PNL obtained by gel filtration chromatography was 22 kDa; the isoelectric point was 8.6, as determined by chromatofocusing; and the enzyme was able to catalyze the eliminative cleavage of pectins with low (37%) and high (from 54 to 82%) degrees of esterification. The PNL produced in liquid medium showed a K m for pectin (degree of esterification, 70%) of 3.2 mg/ml, and the optimum pH was 6.0 to 7.0. This enzyme was stable at 50°C and at pH 8.0. The ability of t...
The use of organic amendments in agriculture is a common practice due to their potential to incre... more The use of organic amendments in agriculture is a common practice due to their potential to increase crop productivity and enhance soil health. Indeed, organic amendments of different origen and composition (e.g., animal slurry, manure, compost, sewage sludge, etc.) can supply valuable nutrients to the soil, as well as increase its organic matter content, with concomitant benefits for soil health. However, the application of organic amendments to agricultural soil entails a variety of risks for environmental and human health. Organic amendments often contain a range of pollutants, including heavy metals, persistent organic pollutants, potential human pathogens, and emerging pollutants. Regarding emerging pollutants, the presence of antibiotic residues, antibiotic-resistant bacteria, and antibiotic-resistance genes in agricultural amendments is currently a matter of much concern, due to the concomitant risks for human health. Similarly, currently, the introduction of microplastics to...
Antibiotic resistance represents one of the greatest threats to global health. The spread of anti... more Antibiotic resistance represents one of the greatest threats to global health. The spread of antibiotic resistance genes among bacteria occurs mostly through horizontal gene transfer via conjugation mediated by plasmids. This process implies a direct contact between a donor and a recipient bacterium which acquires the antibiotic resistance genes encoded by the plasmid and, concomitantly, the capacity to transfer the acquired plasmid to a new recipient. Classical assays for the measurement of plasmid transfer frequency (i.e., conjugation frequency) are often characterized by a high variability and, hence, they require many biological and technical replicates to reduce such variability and the accompanying uncertainty. In addition, classical conjugation assays are commonly tedious and time-consuming because they typically involve counting colonies on a large number of plates for the quantification of donors, recipients, and transconjugants (i.e., the bacteria that have received the ge...
Soils of abandoned and vacant lands in the periphery of cities are frequently subjected to illega... more Soils of abandoned and vacant lands in the periphery of cities are frequently subjected to illegal dumping and can undergo degradation processes such as depletion of organic matter and nutrients, reduced biodiversity, and the presence of contaminants, which may exert an intense abiotic stress on biological communities. Mycorrhizal-assisted phytoremediation and intercropping strategies are highly suitable options for remediation of these sites. A two-year field experiment was conducted at a peri-urban site contaminated with petroleum hydrocarbons and polychlorinated biphenyls, to assess the effects of plant growth (spontaneous plant species, Medicago sativa, and Populus × canadensis, alone vs. intercropped) and inoculation of a commercial arbuscular mycorrhizal and ectomycorrhizal inoculum. Contaminant degradation, plant performance, and biodiversity, as well as a variety of microbial indicators of soil health (microbial biomass, activity, and diversity parameters) were determined. T...
Bacterial resistance to antibiotics poses enormous health and economic burdens to our society, an... more Bacterial resistance to antibiotics poses enormous health and economic burdens to our society, and it is of the essence to explore old and new ways to deal with these problems. Here we review the current status of multi-resistance genes and how they spread among bacteria. We discuss strategies to deal with resistant bacteria, namely the search for new targets and the use of inhibitors of protein-protein interactions, fragment-based methods, or modified antisense RNAs. Finally, we discuss integrated approaches that consider bacterial populations and their niches, as well as the role of global regulators that activate and/or repress the expression of multiple genes in fluctuating environments and, therefore, enable resistant bacteria to colonize new niches. Understanding how the global regulatory circuits work is, probably, the best way to tackle bacterial resistance.
The long-term impact of sewage sludge application on agricultural soil was studied. • We observed... more The long-term impact of sewage sludge application on agricultural soil was studied. • We observed Cu and Zn accumulation in soil, but without increased bioavailability. • We found correlation between soil Cu and Zn concentration and antibiotic resistance. • The composition of soil prokaryotic communities was not significantly altered. • The abundance of some antibiotic resistance genes increased in amended soils.
The application of nanoscale zero-valent iron particles (nZVI) for the remediation of contaminate... more The application of nanoscale zero-valent iron particles (nZVI) for the remediation of contaminated sites is very promising. However, information concerning the ecotoxicity of nZVI on soil microbial communities and, hence, soil quality, is still scarce. We carried out a three-month experiment to evaluate the impact of the application of different concentrations of nZVI (from 1 to 20 mg nZVI g DW soil-1) on soil microbial properties in a clay-loam versus a sandy-loam soil. Data on microbial biomass (total bacteria and fungi by qPCR, microbial biomass carbon), activity (β-glucosidase, arylsulphatase and urease activities), and functional (Biolog Ecoplates TM) and structural (ARISA, 16S rRNA amplicon sequencing) diversity evidenced that the sandy-loam soil was more vulnerable to the presence of nZVI than the clay-loam soil. In the sandy-loam soil, arylsulphatase activity and bacterial abundance, richness and diversity were susceptible to the presence of nZVI. The high content of clay and organic matter present in the clay-loam soil may explain the observed negligible effects of nZVI on soil microbial properties. It was concluded that the impact of nZVI on soil microbial communities and, hence, soil quality, is soil dependent.
Materials science & engineering. C, Materials for biological applications, 2015
Microbial growth on medical and technical devices is a big health issue, particularly when microo... more Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited the growth of the nosocomial pathogens Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by the growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced the growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, wh...
We studied the effectiveness of remediation on microbial endpoints, namely microbial biomass and ... more We studied the effectiveness of remediation on microbial endpoints, namely microbial biomass and activity, microbial and plant species richness, of an As-contaminated mine spoil, amended with compost (C) alone and in combination with beringite (B) or zerovalent iron grit (Z), to increase organic matter content and reduce trace elements mobility, and to allow Holcus lanatus and Pinus pinaster growth. Untreated spoil showed the lowest microbial biomass and activity and hydrolase activities, and H. lanatus as sole plant species, whereas the presented aided phytostabilisation option, especially CBZ treatment, significantly increased microbial biomass and activity and allowed colonisation by several plant species, comparable to those of an uncontaminated sandy soil. Microbial species richness was only increased in spoils amended with C alone. No clear correlation occurred between trace element mobility and microbial parameters and plant species richness. Our results indicate that the choice of indicators of soil remediation practices is a bottleneck.
Staphylococcus epidermidis has emerged as one of the major nosocomial pathogens associated with i... more Staphylococcus epidermidis has emerged as one of the major nosocomial pathogens associated with infections of implanted medical devices. The most important factor in the pathogenesis of these infections is the formation of bacterial biofilms. Bacteria grown in biofilms are more resistant to antibiotics and to the immune defence system than planktonic bacteria. In these infections, the antimicrobial therapy usually fails and the removal of the biofilm-coated implanted device is the only effective solution. In this study, three proteomic approaches were performed to investigate membrane proteins associated to biofilm formation: (i) sample fractionation by gel electrophoresis, followed by isotopic labelling and LC-MS/MS analysis, (ii) in-solution sample preparation, followed by isotopic labelling and LC-MS/MS analysis and (iii) in-solution sample preparation and label-free LC-MS/MS analysis. We found that the commensal strain S. epidermidis CECT 231 grown in biofilms expressed higher levels of five membrane and membrane-associated proteins involved in pathogenesis: accumulation-associated protein, staphylococcal secretory antigen, signal transduction protein TRAP, ribonuclease Y and phenol soluble modulin beta 1 when compared with bacteria grown under planktonic conditions. These results indicate that a commensal strain can acquire a pathogenic phenotype depending on the mode of growth.
EKAIA Euskal Herriko Unibertsitateko Zientzia eta Teknologia Aldizkaria, 2020
Antibiotikoen aurkako erresistentzia duten bakterioak mundu mailako osasun arriskua dira gaur egu... more Antibiotikoen aurkako erresistentzia duten bakterioak mundu mailako osasun arriskua dira gaur egun infekzioak tratatzeko ditugun terapien eraginkortasunaren galera ekar dezaketelako. Mehatxu horri aurre egiteko modu bat eskuartean ditugun farmakoak garraio sistema egokietan txertatzea izan daiteke eraginkortasunaren hobekuntza eta erresistentzien agerpenaren atzeratzea ekar dezaketelako. Farmakoen garraio sistema ezberdinen artean Lipido Solidozko Nanopartikulek ezaugarri ezin hobeak eskaintzen dituzte farmakoen solugarritasuna, iragazkortasuna, askapen-zinetika eta egonkortasuna bezalako ezaugarri garrantzitsuak hobetzeaz gain toxizitatea murrizten laguntzen dutelako. Lipido Solidozko Nanopartikulak nukleo lipidiko solido bat eta emultsionatzaile geruza batez osaturiko nanopartikulak dira, konposatu fisiologikoekin osatzen direnak. Dena den, farmakoen garraio sistema efizienteen garapenak nanopartikula eta sistema biologikoen arteko elkarrekintzen ezaguera eskatzen du eta horretara...
Current topics in microbiology and immunology, 2017
Type IV coupling proteins (T4CPs) are essential constituents of most type IV secretion systems (T... more Type IV coupling proteins (T4CPs) are essential constituents of most type IV secretion systems (T4SSs), and probably the most intriguing component in terms of their evolutionary origen and functional role. Coupling proteins have coevolved with their cognate secretion system and translocated substrates. They are present in all conjugative systems, leading to the suggestion that they play a specific role in DNA transfer. However, they are also part of many T4SSs involved in bacterial virulence, where they are required for protein translocation, with no apparent involvement in DNA secretion. Their name reflects genetic and biochemical evidence of a connecting role between the substrate and the T4SS, thus probably playing a major role in substrate recruitment. Increasing evidence supports also a role in signal transmission leading to activation of secretion. Most studies have addressed conjugative coupling proteins of the VirD4-like protein family. Their conserved features include a nuc...
The increasing rates of antimicrobial resistance among carbapenem-resistant Acinetobacter baumann... more The increasing rates of antimicrobial resistance among carbapenem-resistant Acinetobacter baumannii in the Middle East and North Africa are one of the major concerns for healthcare settings. We characterised the first A. baumannii isolate harbouring five β-lactamases identified in Egypt. The isolate Ale25 was obtained from an ICU patient of a hospital from Alexandria. The isolate was phenotypically and genotypically screened for carbapenemase genes. The isolate was resistant to carbapenems, aminoglycosides, fluoroquinolones and cefiderocol. Whole-Genome Sequencing identified five β-lactamase genes, blaNDM-1, blaOXA-23, blaOXA-64, blaPER-7 and blaADC-57, together with other antibiotic resistance genes, conferring resistance to sulfonamides, macrolides, tetracyclines, rifamycin and chloramphenicol. Virulome analysis showed the presence of genes involved in adhesion and biofilm production, type II and VI secretion systems, exotoxins, etc. Multi-Locus Sequence Typing analysis identified...
Additional Figure 1. Flowsheet of the bacterial P3HB production process in Scenario 1. Green: the... more Additional Figure 1. Flowsheet of the bacterial P3HB production process in Scenario 1. Green: thermo-chemical pre-treatment and enzymatic hydrolysis. Blue: bacterial process. Orange: extraction-separation.
Rapid urbanization followed by economic crisis frequently results in the presence of degraded aba... more Rapid urbanization followed by economic crisis frequently results in the presence of degraded abandoned urban plots inside or in the periphery of cities. Urban greening can be a low-cost solution for their reclamation but, inevitably, the necessary plants require an appropriate medium to grow and thrive. In this study, Technosols were explored as a suitable option to simultaneously face two common challenges of many cities, i.e., the reclamation of degraded abandoned city plots and the recycling of industrial and urban wastes. To this purpose, a mesocosm experiment was carried out to assess the suitability of six different Technosols (resulting from the combination of the following four ingredients: CDW: construction and demolition wastes; BIO: bio-stabilized material from a municipal composting plant; BENT: recycled bentonites from a local industry; TS: topsoil from vacant public plots) for the reclamation of abandoned city plots. The six Technosols were prepared in triplicate and then installed in 12 m 2 experimental cells. Control cells
Organic amendments are being increasingly applied to agricultural soils as alternatives or comple... more Organic amendments are being increasingly applied to agricultural soils as alternatives or complements to inorganic fertilizers. Organic amendments can increase the content of soil organic matter, concomitantly improving soil physical, chemical and biological properties. We evaluated the effect of the application of commercial vs. farm-made fermented liquid organic amendments, compared to mineral (NPK) fertilization, on corn yield and nutritional status, as well as on soil physicochemical and microbial properties as indicators of soil quality. In particular, we assessed the effect of two doses (optimal vs. suboptimal) and times of amendment application (basal dressing vs. basal + top dressing) for two consecutive growing seasons. Values of corn grain yield were lower in organically-amended plots than in those under NPK fertilization. At the optimal dose, the application of organic amendments led to significantly higher values of microbial activity (soil respiration; enzyme activities; potentially mineralizable N) and biomass (microbial biomass C, bacterial and fungal biomass), leading to an improvement in soil quality. The optimal application dose resulted in an enhanced soil nutrient pool. Conversely, soil properties were not significantly affected by the origen of the amendment (commercial vs. farm-made) or the time of application (basal dressing vs. basal + top dressing). 16S rRNA metabarcoding analysis revealed no significant changes in the diversity and composition of the soil prokaryotic communities between organically-amended and NPK-fertilized soils. It was concluded that the application of fermented liquid organic amendments at the optimal dose (according to the N requirements of corn) can be a beneficial agronomic practice for agricultural soil quality, posing a suitable alternative to mineral fertilization.
The anaerobic decomposition of organic wastes might lead to the formation of organic-byproducts w... more The anaerobic decomposition of organic wastes might lead to the formation of organic-byproducts which can then be successfully used as organic fertilizers. This study evaluated the impact of the application of two fermented liquid organic amendments (commercial vs. farm-made) at two doses of application (optimal vs. suboptimal), compared to mineral fertilization, on lettuce growth and soil quality. To this purpose, two experiments were conducted at microcosm-and field-scale, respectively. In the microcosm experiment, organically amended soils resulted in lower lettuce yield than minerally fertilized soil but, in contrast, they enhanced microbial activity and biomass, thus leading to an improvement in soil quality. The fertilization regime (organic vs. inorganic) significantly affected soil microbial composition but did not have any significant effect on structural or functional prokaryotic diversity. In the field experiment, at the optimal dose of application, organically-amended soils resulted in comparable lettuce yield to that displayed by minerally fertilized soils. The application of organic amendments did not result in an enhanced microbial activity and biomass, compared to mineral fertilization, but led to a higher soil prokaryotic diversity. Among the organically-amended plots, the optimal application dose resulted in a higher lettuce yield and soil microbial activity and biomass, but led to a decline in soil prokaryotic diversity, compared to the suboptimal application dose. Our results indicate that commercial and farm-made fermented liquid organic amendments possess the potential to ameliorate soil quality while sustaining crop yield. Given the strong influence of other factors (e.g., type of soil, dose of application) on the effects exerted by such amendments on soil quality and fertility, we recommend that an exhaustive characterization of both the amendments and the recipient soils should be carried out prior to their application, in order to better ensure their potential beneficial effects.
An extracellular pectin lyase (PNL) [poly-(methoxygalacturonide)lyase; EC 4.2.2.10] produced by P... more An extracellular pectin lyase (PNL) [poly-(methoxygalacturonide)lyase; EC 4.2.2.10] produced by Penicillium italicum CECT 2294 grown on a surface bran (natural medium) or in a submerged (synthetic medium) culture was investigated. Both culture filtrates showed macerating activity at low pH on cucumber, potato, and orange tissues. The physicochemical properties of the enzyme obtained from both culture methods were identical, as well as its catalytic properties, which were assayed by different methods. The molecular mass of the PNL obtained by gel filtration chromatography was 22 kDa; the isoelectric point was 8.6, as determined by chromatofocusing; and the enzyme was able to catalyze the eliminative cleavage of pectins with low (37%) and high (from 54 to 82%) degrees of esterification. The PNL produced in liquid medium showed a K m for pectin (degree of esterification, 70%) of 3.2 mg/ml, and the optimum pH was 6.0 to 7.0. This enzyme was stable at 50°C and at pH 8.0. The ability of t...
The use of organic amendments in agriculture is a common practice due to their potential to incre... more The use of organic amendments in agriculture is a common practice due to their potential to increase crop productivity and enhance soil health. Indeed, organic amendments of different origen and composition (e.g., animal slurry, manure, compost, sewage sludge, etc.) can supply valuable nutrients to the soil, as well as increase its organic matter content, with concomitant benefits for soil health. However, the application of organic amendments to agricultural soil entails a variety of risks for environmental and human health. Organic amendments often contain a range of pollutants, including heavy metals, persistent organic pollutants, potential human pathogens, and emerging pollutants. Regarding emerging pollutants, the presence of antibiotic residues, antibiotic-resistant bacteria, and antibiotic-resistance genes in agricultural amendments is currently a matter of much concern, due to the concomitant risks for human health. Similarly, currently, the introduction of microplastics to...
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