Carina Audisio - Academia.edu (original) (raw)
Papers by Carina Audisio
American Journal of Enology and Viticulture, 2009
The effects of a surfactin from Bacillus subtilis C4 on the extraction of anthocyanins, other pig... more The effects of a surfactin from Bacillus subtilis C4 on the extraction of anthocyanins, other pigments, and total polyphenols by action of a pectinase from Bacillus sp. SC-H during a short maceration of Malbec grape skins were studied. A prefermentative extraction from skins free of pulp and seeds with an extraction solution in absence of ethanol for 2 hours was carried out. Color was measured by tristimulus colorimetry and traditional indices (color index, shade, and total polyphenol content) and anthocyanins were determined by HPLC. The color index increased from 2.878 ± 0.281 for natural extraction, to 5.500 ± 0.107 for samples with pectinase plus 0.095% surfactin, and to 6.036 ± 1.013 for samples with pectinase plus 0.286% surfactin. Total polyphenol content increased from 555.77 ± 5.00 mg GAE/L for natural extraction to 769.71 ± 38.21 mg GAE/L and to 769.05 ± 8.40 mg GAE/L for the aforementioned samples. Anthocyanic compounds were readily released from grape skins, especially m...
In Argentina, cassava leaves are considered a crop waste, despite their high content of proteins ... more In Argentina, cassava leaves are considered a crop waste, despite their high content of proteins and other nutrients, like vitamins and minerals. The aim of this research was to evaluate the nutritional profile of leaves of three cassava varieties: Mico, Pomberi and Campeona, grown in Formosa province, and to study the effect of different thermal treatments on cyanoglycosides content. Protein, NDF, ADF, carbohydrates content of cassava leaves was determined. The concentration of cyanoglycosides in fresh leaves ranged from 242 to 401 ppm with the highest values being recorded in Mico and Pomberi varieties. Mean essential amino acid content was 44 %, with a predominance of lysine (5.92–7.02), phenylalanine (5.62–7.13), and leucine (7.35–9.30 g/100 g protein). In all cases, Campeona had the highest concentration of those amino acids. The greatest reduction in cyanoglycosides was achieved by combining heat treatments; the combination of “blanching − dry heating − wet heating” was the mo...
Fil: Goni, Maria Gabriela. Universidad Nacional de La Plata. Facultad de Ingenieria. Departament... more Fil: Goni, Maria Gabriela. Universidad Nacional de La Plata. Facultad de Ingenieria. Departamento de Ingenieria Quimica; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina
Microbiology Resource Announcements
This report describes the draft genome sequences of Lactobacillus salivarius A3iob and Lactobacil... more This report describes the draft genome sequences of Lactobacillus salivarius A3iob and Lactobacillus johnsonii CRL1647, probiotic strains isolated from the gut of honeybee Apis mellifera workers. The reads were generated by a whole-genome sequencing (WGS) strategy on an Illumina MiSeq sequencer and were assembled into contigs with total sizes of 2,054,490 and 2,137,413 bp for the A3iob and CRL1647 strains, respectively. The draft genome sequences of L. salivarius A3iob and L. johnsonii CRL1647 will be useful for further studies of the specific genetic features of these strains and for understanding the mechanisms of their probiotic properties.
Probiotics and Antimicrobial Proteins
Lactobacillus salivarius A3iob was administered to productive colonies belonging to commercial ap... more Lactobacillus salivarius A3iob was administered to productive colonies belonging to commercial apiaries of small beekeepers (around 30–50 hives each one), from four departments of the province of Jujuy (Argentina): Yala, Tilquiza, El Carmen, and Los Alisos. The incidence of Varroa destructor and Nosema spp., before and after winter, was monitored during 2 years of study (2014–2015). Depending on the geographical location of each apiary and the application time, a monthly dose of the bacteria (105 CFU/mL) reduced the levels of varroasis between 50 and 80%. Interestingly, L. salivarius A3iob cells remitted the percentage of the mites to undetectable values in an apiary treated with flumethrin (at Yala, Yungas region). On the other hand, the spore levels of Nosema spp. in the lactobacilli-treated colonies also depended on the apiary and the year of application, but a significant decrease was mainly observed in the post-winter period. However, at Rivera (El Carmen’s department), no significant changes were detected in both parameters. These results obtained after 2 years of work suggest that delivering L. salivarius A3iob cells to the bee colonies can become a new eco-friendly tool to cooperate with the control of these bees’ pests.
Biological Control
Abstract Soil is the foundation for agriculture and the medium where almost all food-producing pl... more Abstract Soil is the foundation for agriculture and the medium where almost all food-producing plants are grown. Extensive use of fertilizers and pesticides has affected soil quality, with dangerous ecological effects; therefore, environmentally friendly biological alternatives have been widely recommended. This study explored the potential of Bacillus sp. P12 strain for improving soil quality and consequently favoring growth of common bean (Phaseolus vulgaris L.) and, on the other hand, for controlling infection with the plant pathogen Macrophomina phaseolina, which induces charcoal rot. P12 inhibited in vitro the development of six native M. phaseolina strains isolated from Salta region, with fungal inhibition ranging between 55 and 70%. This bacilli synthesized different isoforms of the lipopeptides kurstakin, surfactin, iturin, polimyxin and fengycin in the presence of the plant pathogen, as determined by MALDI-TOF. Under greenhouse conditions, incidence of M. phaseolina was 100% in white common bean cv. Alubia in the control treatment, whereas seeds inoculated with P12 showed a 40% reduction of the pathogen effect at the end of the trial. Activities of the soil enzymes FDA, DHA and AP were increased (22, 31 and 6.2%, respectively) in the rhizosphere where P12-treated seeds were grown. P12 treatment decreased metabolic quotient, suggesting greater metabolic efficiency. P12 also enhanced the glomalin-related soil protein in the rhizosphere soil. Moreover, populations of the potential native biocontrol agents Trichoderma spp. and Gliocladium spp. increased in the rhizosphere where P12 treatment was applied. Here, Bacillus sp. P12 was found to not only is a potential biocontrol agent, but also improves soil quality, which would enhance properties required for maintaining a healthy soil, rich in nutrients and beneficial microorganisms, thereby improving agricultural production.
International Dairy Journal
Abstract Bacteriocins synthesised by lactic acid bacteria are natural alternatives to control Lis... more Abstract Bacteriocins synthesised by lactic acid bacteria are natural alternatives to control Listeria monocytogenes, a foodborne pathogen. Additionally, antimicrobial biopolymer coatings have significant benefits in food packaging and preservation. The effect of anti-L. monocytogenes enterocins synthesised by Enterococcus avium DSMZ17511 was evaluated when supported on agar edible films and applied as antimicrobial coatings on different cheese matrices artificially contaminated with L. monocytogenes 01/155. A decrease of at least 1 log unit in viability of the pathogen was detected. The wetter matrix of soft cheese facilitated rapid diffusion of the antimicrobials, while the drier matrix of semi hard cheese produced a gradual release with prolonged inhibition of the pathogen. Also, DSMZ17511 antimicrobial peptides, only at very high concentrations, exhibited mild cytotoxicity against L929 and Caco-2 cell lines. Therefore, application of these enterocin agar coatings could be an effective, low cost, natural and safe alternative to control L. monocytogenes in cheeses.
Microbiological Research
Myzus persicae Sulzer (Hemiptera: Aphididae), is a generalist cosmopolitan insect that infests mo... more Myzus persicae Sulzer (Hemiptera: Aphididae), is a generalist cosmopolitan insect that infests more than 400 plant species of 40 different families and is one of the major pests infesting potato crops. It causes direct damage and also spread plant viruses. The intensive use of synthetic insecticide to control aphids has led to resistant populations. Therefore, there is a need to develop biopesticides for effective control that minimizes environmental hazards. The bacteria Bacillus amyloliquefaciens is recognized as a producer of a variety of bioactive compounds. The aim here was to evaluate the aphicidal effect of B. amyloliquefaciens strains, CBMDDrag3, PGPBacCA2, and CBMDLO3, and their metabolites on the mortality and fecundity of M. persicae. Cells suspensions, heat-killed cell suspensions, cell-free supernatants, or isolated lipopeptide fractions from B. amyloliquefaciens strains were offered to aphids through artificial diets. The isolated lipopeptide fractions composed mainly of kurstakins, surfactins, iturins, and fengycins, when were administrated through diets, had no aphicidal effect against M. persicae. However, aphids fed on diets with whole cell suspensions and its cell-free supernatant of all three bacteria strains resulted in 100% mortality of adult aphids and nymphs. Specially, B. amyloliquefaciens CBMDLO3, has an effective aphicidal effect on M. persicae, used both bacterial cells and their metabolites. Moreover, heat-killed cells of B. amyloliquefaciens CBMDLO3 also had aphicidal action, although the aphid mortality was lower than on diet with living bacteria. Therefore, these results propose that B. amyloliquefaciens, could function as a novel eco-friendly biopesticide for the control of M. persicae.
Probiotics and Antimicrobial Proteins
Journal of Apicultural Science
The European honey bee (Apis mellifera L.) is known to be affected by such stress factors as path... more The European honey bee (Apis mellifera L.) is known to be affected by such stress factors as pathogen load, poor nutrition and depressed immunity. Nosema ceranae is one of the main parasites that affect colony populations. The relationship between the stress factors and honey bee-bacteria symbiosis appears as an alternative to enhance bee health. The aim of this study was to evaluate the effect of the oral administration of bacterial metabolites produced by Lactobacillus johnsonii AJ5 on nutritional parameters, the N. ceranae development and the performance of A. mellifera colonies. Laboratory assays were performed and demonstrated that the bacterial metabolites did not have a toxic effect on bees. Field trial showed an increase of colonies population over time. Also, a decreasing trend of fat bodies per bee was detected in all colonies but there were no evident changes on abdomen protein content at the end of the assay. Lastly, N. ceranae prevalence showed a tendency to reduce with...
Biological Control
Abstract The objective of this study was to isolate strains of the genus Bacillus from different ... more Abstract The objective of this study was to isolate strains of the genus Bacillus from different productive soils of the province of Salta, Argentina, which have growth promoting properties in common bean (Phaseolus vulgaris L.) and have the ability to inhibit different phytopathogenic fungi, primarily Macrophomina phaseolina. Among the 105 strains of bacilli checked, Bacillus sp. B14 was selected for having the greatest in vitro inhibitory effect against Sclerotium rolfsii, Sclerotinia sclerotiurum, Rhizoctonia solani, Fusarium solani and Macrophomina phaseolina, recording fungal inhibition values that varied between 60 and 80%. In addition, B14 produced auxins in a concentration of 10.10 mg/ml, and qualitatively synthesizes siderophores. Based on 16S rRNA gene sequencing, the strain was characterized as B. amyloliquefaciens. Data from greenhouse experiments showed that the black common bean cv. Nag 12 seeds inoculated with B14, had increased germination of 10%, as well as an increase in root length of 2 cm and in shoot length of 6 cm compared with the non-inoculated control seeds. When the phytosanitary state of the B14 inoculated seeds was analyzed, no growth of bacteria, or phytopathogenic fungi and contaminants was observed, while in the non-inoculated seeds, bacteria was found in 46% of seeds, in addition to other phytopathogenic fungi. B. amyloliquefaciens B14 reduced the incidence of M. phaseolina by 62% in the inoculated black bean cv. Nag 12 seeds. Furthermore, using MALDI-MS it was determined that the bacteria synthesized different lipopeptides in the presence of M. phaseolina, such as surfactin, iturin, fengycin, kurstatin and polymyxin, leading us to conclude that they are the main responsible for the antagonistic effect observed and that the nature of lipopeptides synthesized by B14 is influenced by target fungal strain.
Biological Control
Abstract Bacillus amyloliquefaciens PGPBacCA1 was studied regarding its aptitude to protect commo... more Abstract Bacillus amyloliquefaciens PGPBacCA1 was studied regarding its aptitude to protect common bean seeds from their intrinsic pathogens. Also, the inhibition of different environmental phytopathogenic fungi was tested. Two cultivars of Phaseolus vulgaris L. were evaluated: cv. Nag (black bean) and cv. Alubia (white bean). Aspergillus spp., Penicillium spp. and Fusarium spp. constituted the natural fungal biota of both seeds, whereas white bean and black bean also exhibited Cladosporium spp. and Rhizopus spp., respectively. B. amyloliquefaciens PGPBacCA1 prevented the development of the endophytic fungi of black bean, while only Cladosporium spp. survived in the white variety. Growth chamber assays were carried out and bacilli cells were applied on seeds without affecting neither the vigor nor the germination potential of either type of bean. In addition, B. amyloliquefaciens PGPBacCA1, by dual cultures, was able to inhibit the development of the following phytopathogenic fungi: Sclerotium rolfsii (35%), Sclerotinia sclerotiorum (76.5%), Rhizoctonia solani (73%), Fusarium solani (56.5%), and Penicillium spp. (71.5%). The UV-MALDI TOF MS analysis showed that B. amyloliquefaciens PGPBacCA1 co-produces different homologues of the lipopeptides surfactin, iturin and fengycin in the presence of S. sclerotiorum and F. solani . These compounds were identified as the main responsible for the antagonistic effect. SEM analysis confirmed the antifungal effects of the lipopeptides, which also caused damage to chlamydospores and sclerotia of Fusarium and Sclerotinia , respectively. B. amyloliquefaciens PGPBacCA1 can thus be applied to these bean seeds varieties as a potential bioprotection agent.
Journal of Materials Science
The aim of this work was to evaluate the release profile of vancomycin hydrochloride (VC), as wel... more The aim of this work was to evaluate the release profile of vancomycin hydrochloride (VC), as well as the degradation, in vitro antistaphylococcal effect and cytotoxicity in MG-63 osteoblast-like cells of gelatin-starch (GS) films added with different concentrations of microparticles of the bioactive glass 45S5 (m-BG). The biomaterials were obtained through the gel-casting method. Four different composites were prepared at four different weight percentages of m-BG: 0, 5, 10, and 15 %. Glutaraldehyde 0.25 wt% (GA) was used as the cross-linker. The composites were characterized by scanning electron microscopy and the in vitro degradation of the films was studied by measuring the water uptake and weight loss. The drug release kinetics was quantified spectrophotometrically. The inhibition zone test and the plate count method were used to evaluate the antibacterial activity of the samples. Three staphylococcus strains were evaluated: Staphylococcus aureus ATCC6538, S. aureus ATCC29213, and Staphylococcus epidermidis ATCC12228. Cytotoxicity effects were evaluated through the MTT assay. The addition of m-BG to GS films showed no effects on the amount of water uptake, but led to an increase in the weight loss over time, even with m-BG content. The release rate of VC was also affected by the increasing concentration of m-BG in the composite films. However, the antibacterial effects of the composites were not improved by this modulation. All composites strongly inhibited staphylococcal cells with similar strength. On the other hand, liquid extracts from the composites resulted in cytotoxic effects on MG-63 osteoblastlike cells due to the presence of GA, but not to the concentration of VC or m-BG.
Research in Microbiology, Apr 30, 2009
Three Bacillus strains isolated from honey samples and bee gut were pre-selected for their in vit... more Three Bacillus strains isolated from honey samples and bee gut were pre-selected for their in vitro antimicrobial activity against Paenibacillus larvae and Ascosphaera apis, important honeybee pathogens. The analysis of their 16S rRNA sequences revealed that C4, M1 and G2III strains belong to the subtilis species. Surfactin synthesis was verified by IR spectroscopy and HPLC studies. Surfactin inhibited P. larvae but it failed to affect A. apis. Vegetative cells of P. larvae were affected as soon as they came in contact with the surfactin sample; two orders of magnitude less in log scale were recorded. Optimal surfactin production was observed in MEL medium, a broth with molasses as the only carbon source. Bacillus subtilis G2III strain exhibited the highest levels of surfactin synthesis in BHI and MEL broths: 1391 AU/ml and 2782 AU/ml, respectively. Since only A. apis inhibition was observed when cell suspensions were assayed, we suspect that there may be an antimycotic compound within cells. The co-production of surfactin and a fungicide by these strains might biologically control bee pathogens in apiculture.
Journal of Food Processing and Preservation, 2016
The adsorption of a commercial form of nisin, Nisaplin® (Npl) (Danisco), on montmorillonite (Mt),... more The adsorption of a commercial form of nisin, Nisaplin® (Npl) (Danisco), on montmorillonite (Mt), a natural inexpensive clay mineral accepted as food additive, was assayed. The intention was to develop food grade materials capable of releasing the peptide and avoiding negative interactions that affect nisin antimicrobial activity in food environments. A set of different Mt-Npl relation samples was prepared. The antimicrobial activity and the total organic carbon/total nitrogen (TOC/TN) content measured in nisin solutions after contact with the clay decreased as the amount of solid increased; thus, indicating the adsorption of the peptide on the support. Also, the Mt-Npl solids presented inhibitory activity against Enterococcus faecium C1. Additionally, Fourier Transform-Infrared Attenuated Total Reflectance spectroscopy (FT-IR-ATR) analysis of the Mt-Npl lyophilised systems showed that nisin was preferably adsorbed on Mt among Nisaplin® ingredients, suggesting a unique concentration and immobilization method for this antimicrobial peptide that could be applied in food preservation. Practical Applications Montmorillonite (Mt) is an inexpensive abundant natural clay characterized by a moderate cation exchange capacity with high surface area. Nisaplin® is a commercial form of nisin, a polypeptide bacteriocin active against several Gram-positive food spoilage and pathogen microorganisms. The increasing demand for fresh and natural food favors the application of biopreservatives such as nisin. However, the interaction of these antimicrobials with other food components reduces their inhibitory effect when directly introduced into food systems. Thus, alternatives for the inclusion of active biomolecules in foods are necessary. Since Mt is a potential food additive, its use as a nisin immobilization agent provides a strategy to protect and optimize the gradual peptide liberation. This immobilization approach does not only offer a simple, rapid, and low cost method for the concentration of nisin, but also provides a feasible alternative procedure for the introduction of this antimicrobial peptide in food complex systems.
Biomedical glasses, 2015
To prevent the high frequency of wound infections, anti-bacterial agents can be loaded onto compo... more To prevent the high frequency of wound infections, anti-bacterial agents can be loaded onto composites. In the present study, the antibiotic tetracycline hydrochloride (TC)was incorporated, for the first time, in collagen type I membranes coated with nano-sized SiO2-CaOP2O5 bioactive glass (n-BG) obtained by a sol-gel chemical route.Collagen membranes coated with n-BG were immersed in simulated body fluid (SBF) containing 0.25, 0.75 or 1.25 mg mL−1 of TC for 48 h at 37∘C following a coprecipitation method. The antibiotic was released in distilledwater at 37∘C for up to 72 h. The antibacterial activity of the composites was evaluated in vitro by the inhibition zone test and plate count method. Two different Staphylococcus aureus strains, S. aureus ATCC29213 and S. aureus ATCC25923, were exposed to the biomaterials. The results showed that the incorporation but not the release of TC was dependent on the initial concentration of TC in SBF. The biomaterials inhibited S. aureus growth, a...
Research Journal of Microbiology, 2006
Environmental Microbiology, 2004
Probiotics and antimicrobial proteins, 2014
Bacillus cereus is an endospore-forming, Gram-positive bacterium able to cause foodborne diseases... more Bacillus cereus is an endospore-forming, Gram-positive bacterium able to cause foodborne diseases. Lactic acid bacteria (LAB) are known for their ability to synthesize organic acids and bacteriocins, but the potential of these compounds against B. cereus has been scarcely documented in food models. The present study has examined the effect of the metabolites produced by Lactobacillus johnsonii CRL1647 and Enterococcus faecium SM21 on the viability of select B. cereus strains. Furthermore, the effect of E. faecium SM21 metabolites against B. cereus strains has also been investigated on a rice food model. L. johnsonii CRL1647 produced 128 mmol/L of lactic acid, 38 mmol/L of acetic acid and 0.3 mmol/L of phenyl-lactic acid. These organic acids reduced the number of vegetative cells and spores of the B. cereus strains tested. However, the antagonistic effect disappeared at pH 6.5. On the other hand, E. faecium SM21 produced only lactic and acetic acid (24.5 and 12.2 mmol/L, respectively...
Journal of food protection, 1999
Production of antagonistic compounds was studied in a strain of Enterococcus faecium isolated fro... more Production of antagonistic compounds was studied in a strain of Enterococcus faecium isolated from the intestinal tract of a free-ranging chicken. Production of lactic acid and a bacteriocin was observed in cultures of this bacterium, alone and in mixed culture fermentations with pathogenic Salmonella serotypes (i.e., Gallinarum, Pullorum, Enteritidis, and Typhimurium). Growth inhibition of these avian and human pathogens was observed after 4 h of incubation at 37 degrees C in CAm broth, a medium developed according to the nutrients present in chicken food. The antibacterial action was due to the combined effect of lactic acid and bacteriocin. Accumulation of these metabolites caused both a bacteriostatic and a bactericidal action against the gram-negative bacteria assayed.
American Journal of Enology and Viticulture, 2009
The effects of a surfactin from Bacillus subtilis C4 on the extraction of anthocyanins, other pig... more The effects of a surfactin from Bacillus subtilis C4 on the extraction of anthocyanins, other pigments, and total polyphenols by action of a pectinase from Bacillus sp. SC-H during a short maceration of Malbec grape skins were studied. A prefermentative extraction from skins free of pulp and seeds with an extraction solution in absence of ethanol for 2 hours was carried out. Color was measured by tristimulus colorimetry and traditional indices (color index, shade, and total polyphenol content) and anthocyanins were determined by HPLC. The color index increased from 2.878 ± 0.281 for natural extraction, to 5.500 ± 0.107 for samples with pectinase plus 0.095% surfactin, and to 6.036 ± 1.013 for samples with pectinase plus 0.286% surfactin. Total polyphenol content increased from 555.77 ± 5.00 mg GAE/L for natural extraction to 769.71 ± 38.21 mg GAE/L and to 769.05 ± 8.40 mg GAE/L for the aforementioned samples. Anthocyanic compounds were readily released from grape skins, especially m...
In Argentina, cassava leaves are considered a crop waste, despite their high content of proteins ... more In Argentina, cassava leaves are considered a crop waste, despite their high content of proteins and other nutrients, like vitamins and minerals. The aim of this research was to evaluate the nutritional profile of leaves of three cassava varieties: Mico, Pomberi and Campeona, grown in Formosa province, and to study the effect of different thermal treatments on cyanoglycosides content. Protein, NDF, ADF, carbohydrates content of cassava leaves was determined. The concentration of cyanoglycosides in fresh leaves ranged from 242 to 401 ppm with the highest values being recorded in Mico and Pomberi varieties. Mean essential amino acid content was 44 %, with a predominance of lysine (5.92–7.02), phenylalanine (5.62–7.13), and leucine (7.35–9.30 g/100 g protein). In all cases, Campeona had the highest concentration of those amino acids. The greatest reduction in cyanoglycosides was achieved by combining heat treatments; the combination of “blanching − dry heating − wet heating” was the mo...
Fil: Goni, Maria Gabriela. Universidad Nacional de La Plata. Facultad de Ingenieria. Departament... more Fil: Goni, Maria Gabriela. Universidad Nacional de La Plata. Facultad de Ingenieria. Departamento de Ingenieria Quimica; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina
Microbiology Resource Announcements
This report describes the draft genome sequences of Lactobacillus salivarius A3iob and Lactobacil... more This report describes the draft genome sequences of Lactobacillus salivarius A3iob and Lactobacillus johnsonii CRL1647, probiotic strains isolated from the gut of honeybee Apis mellifera workers. The reads were generated by a whole-genome sequencing (WGS) strategy on an Illumina MiSeq sequencer and were assembled into contigs with total sizes of 2,054,490 and 2,137,413 bp for the A3iob and CRL1647 strains, respectively. The draft genome sequences of L. salivarius A3iob and L. johnsonii CRL1647 will be useful for further studies of the specific genetic features of these strains and for understanding the mechanisms of their probiotic properties.
Probiotics and Antimicrobial Proteins
Lactobacillus salivarius A3iob was administered to productive colonies belonging to commercial ap... more Lactobacillus salivarius A3iob was administered to productive colonies belonging to commercial apiaries of small beekeepers (around 30–50 hives each one), from four departments of the province of Jujuy (Argentina): Yala, Tilquiza, El Carmen, and Los Alisos. The incidence of Varroa destructor and Nosema spp., before and after winter, was monitored during 2 years of study (2014–2015). Depending on the geographical location of each apiary and the application time, a monthly dose of the bacteria (105 CFU/mL) reduced the levels of varroasis between 50 and 80%. Interestingly, L. salivarius A3iob cells remitted the percentage of the mites to undetectable values in an apiary treated with flumethrin (at Yala, Yungas region). On the other hand, the spore levels of Nosema spp. in the lactobacilli-treated colonies also depended on the apiary and the year of application, but a significant decrease was mainly observed in the post-winter period. However, at Rivera (El Carmen’s department), no significant changes were detected in both parameters. These results obtained after 2 years of work suggest that delivering L. salivarius A3iob cells to the bee colonies can become a new eco-friendly tool to cooperate with the control of these bees’ pests.
Biological Control
Abstract Soil is the foundation for agriculture and the medium where almost all food-producing pl... more Abstract Soil is the foundation for agriculture and the medium where almost all food-producing plants are grown. Extensive use of fertilizers and pesticides has affected soil quality, with dangerous ecological effects; therefore, environmentally friendly biological alternatives have been widely recommended. This study explored the potential of Bacillus sp. P12 strain for improving soil quality and consequently favoring growth of common bean (Phaseolus vulgaris L.) and, on the other hand, for controlling infection with the plant pathogen Macrophomina phaseolina, which induces charcoal rot. P12 inhibited in vitro the development of six native M. phaseolina strains isolated from Salta region, with fungal inhibition ranging between 55 and 70%. This bacilli synthesized different isoforms of the lipopeptides kurstakin, surfactin, iturin, polimyxin and fengycin in the presence of the plant pathogen, as determined by MALDI-TOF. Under greenhouse conditions, incidence of M. phaseolina was 100% in white common bean cv. Alubia in the control treatment, whereas seeds inoculated with P12 showed a 40% reduction of the pathogen effect at the end of the trial. Activities of the soil enzymes FDA, DHA and AP were increased (22, 31 and 6.2%, respectively) in the rhizosphere where P12-treated seeds were grown. P12 treatment decreased metabolic quotient, suggesting greater metabolic efficiency. P12 also enhanced the glomalin-related soil protein in the rhizosphere soil. Moreover, populations of the potential native biocontrol agents Trichoderma spp. and Gliocladium spp. increased in the rhizosphere where P12 treatment was applied. Here, Bacillus sp. P12 was found to not only is a potential biocontrol agent, but also improves soil quality, which would enhance properties required for maintaining a healthy soil, rich in nutrients and beneficial microorganisms, thereby improving agricultural production.
International Dairy Journal
Abstract Bacteriocins synthesised by lactic acid bacteria are natural alternatives to control Lis... more Abstract Bacteriocins synthesised by lactic acid bacteria are natural alternatives to control Listeria monocytogenes, a foodborne pathogen. Additionally, antimicrobial biopolymer coatings have significant benefits in food packaging and preservation. The effect of anti-L. monocytogenes enterocins synthesised by Enterococcus avium DSMZ17511 was evaluated when supported on agar edible films and applied as antimicrobial coatings on different cheese matrices artificially contaminated with L. monocytogenes 01/155. A decrease of at least 1 log unit in viability of the pathogen was detected. The wetter matrix of soft cheese facilitated rapid diffusion of the antimicrobials, while the drier matrix of semi hard cheese produced a gradual release with prolonged inhibition of the pathogen. Also, DSMZ17511 antimicrobial peptides, only at very high concentrations, exhibited mild cytotoxicity against L929 and Caco-2 cell lines. Therefore, application of these enterocin agar coatings could be an effective, low cost, natural and safe alternative to control L. monocytogenes in cheeses.
Microbiological Research
Myzus persicae Sulzer (Hemiptera: Aphididae), is a generalist cosmopolitan insect that infests mo... more Myzus persicae Sulzer (Hemiptera: Aphididae), is a generalist cosmopolitan insect that infests more than 400 plant species of 40 different families and is one of the major pests infesting potato crops. It causes direct damage and also spread plant viruses. The intensive use of synthetic insecticide to control aphids has led to resistant populations. Therefore, there is a need to develop biopesticides for effective control that minimizes environmental hazards. The bacteria Bacillus amyloliquefaciens is recognized as a producer of a variety of bioactive compounds. The aim here was to evaluate the aphicidal effect of B. amyloliquefaciens strains, CBMDDrag3, PGPBacCA2, and CBMDLO3, and their metabolites on the mortality and fecundity of M. persicae. Cells suspensions, heat-killed cell suspensions, cell-free supernatants, or isolated lipopeptide fractions from B. amyloliquefaciens strains were offered to aphids through artificial diets. The isolated lipopeptide fractions composed mainly of kurstakins, surfactins, iturins, and fengycins, when were administrated through diets, had no aphicidal effect against M. persicae. However, aphids fed on diets with whole cell suspensions and its cell-free supernatant of all three bacteria strains resulted in 100% mortality of adult aphids and nymphs. Specially, B. amyloliquefaciens CBMDLO3, has an effective aphicidal effect on M. persicae, used both bacterial cells and their metabolites. Moreover, heat-killed cells of B. amyloliquefaciens CBMDLO3 also had aphicidal action, although the aphid mortality was lower than on diet with living bacteria. Therefore, these results propose that B. amyloliquefaciens, could function as a novel eco-friendly biopesticide for the control of M. persicae.
Probiotics and Antimicrobial Proteins
Journal of Apicultural Science
The European honey bee (Apis mellifera L.) is known to be affected by such stress factors as path... more The European honey bee (Apis mellifera L.) is known to be affected by such stress factors as pathogen load, poor nutrition and depressed immunity. Nosema ceranae is one of the main parasites that affect colony populations. The relationship between the stress factors and honey bee-bacteria symbiosis appears as an alternative to enhance bee health. The aim of this study was to evaluate the effect of the oral administration of bacterial metabolites produced by Lactobacillus johnsonii AJ5 on nutritional parameters, the N. ceranae development and the performance of A. mellifera colonies. Laboratory assays were performed and demonstrated that the bacterial metabolites did not have a toxic effect on bees. Field trial showed an increase of colonies population over time. Also, a decreasing trend of fat bodies per bee was detected in all colonies but there were no evident changes on abdomen protein content at the end of the assay. Lastly, N. ceranae prevalence showed a tendency to reduce with...
Biological Control
Abstract The objective of this study was to isolate strains of the genus Bacillus from different ... more Abstract The objective of this study was to isolate strains of the genus Bacillus from different productive soils of the province of Salta, Argentina, which have growth promoting properties in common bean (Phaseolus vulgaris L.) and have the ability to inhibit different phytopathogenic fungi, primarily Macrophomina phaseolina. Among the 105 strains of bacilli checked, Bacillus sp. B14 was selected for having the greatest in vitro inhibitory effect against Sclerotium rolfsii, Sclerotinia sclerotiurum, Rhizoctonia solani, Fusarium solani and Macrophomina phaseolina, recording fungal inhibition values that varied between 60 and 80%. In addition, B14 produced auxins in a concentration of 10.10 mg/ml, and qualitatively synthesizes siderophores. Based on 16S rRNA gene sequencing, the strain was characterized as B. amyloliquefaciens. Data from greenhouse experiments showed that the black common bean cv. Nag 12 seeds inoculated with B14, had increased germination of 10%, as well as an increase in root length of 2 cm and in shoot length of 6 cm compared with the non-inoculated control seeds. When the phytosanitary state of the B14 inoculated seeds was analyzed, no growth of bacteria, or phytopathogenic fungi and contaminants was observed, while in the non-inoculated seeds, bacteria was found in 46% of seeds, in addition to other phytopathogenic fungi. B. amyloliquefaciens B14 reduced the incidence of M. phaseolina by 62% in the inoculated black bean cv. Nag 12 seeds. Furthermore, using MALDI-MS it was determined that the bacteria synthesized different lipopeptides in the presence of M. phaseolina, such as surfactin, iturin, fengycin, kurstatin and polymyxin, leading us to conclude that they are the main responsible for the antagonistic effect observed and that the nature of lipopeptides synthesized by B14 is influenced by target fungal strain.
Biological Control
Abstract Bacillus amyloliquefaciens PGPBacCA1 was studied regarding its aptitude to protect commo... more Abstract Bacillus amyloliquefaciens PGPBacCA1 was studied regarding its aptitude to protect common bean seeds from their intrinsic pathogens. Also, the inhibition of different environmental phytopathogenic fungi was tested. Two cultivars of Phaseolus vulgaris L. were evaluated: cv. Nag (black bean) and cv. Alubia (white bean). Aspergillus spp., Penicillium spp. and Fusarium spp. constituted the natural fungal biota of both seeds, whereas white bean and black bean also exhibited Cladosporium spp. and Rhizopus spp., respectively. B. amyloliquefaciens PGPBacCA1 prevented the development of the endophytic fungi of black bean, while only Cladosporium spp. survived in the white variety. Growth chamber assays were carried out and bacilli cells were applied on seeds without affecting neither the vigor nor the germination potential of either type of bean. In addition, B. amyloliquefaciens PGPBacCA1, by dual cultures, was able to inhibit the development of the following phytopathogenic fungi: Sclerotium rolfsii (35%), Sclerotinia sclerotiorum (76.5%), Rhizoctonia solani (73%), Fusarium solani (56.5%), and Penicillium spp. (71.5%). The UV-MALDI TOF MS analysis showed that B. amyloliquefaciens PGPBacCA1 co-produces different homologues of the lipopeptides surfactin, iturin and fengycin in the presence of S. sclerotiorum and F. solani . These compounds were identified as the main responsible for the antagonistic effect. SEM analysis confirmed the antifungal effects of the lipopeptides, which also caused damage to chlamydospores and sclerotia of Fusarium and Sclerotinia , respectively. B. amyloliquefaciens PGPBacCA1 can thus be applied to these bean seeds varieties as a potential bioprotection agent.
Journal of Materials Science
The aim of this work was to evaluate the release profile of vancomycin hydrochloride (VC), as wel... more The aim of this work was to evaluate the release profile of vancomycin hydrochloride (VC), as well as the degradation, in vitro antistaphylococcal effect and cytotoxicity in MG-63 osteoblast-like cells of gelatin-starch (GS) films added with different concentrations of microparticles of the bioactive glass 45S5 (m-BG). The biomaterials were obtained through the gel-casting method. Four different composites were prepared at four different weight percentages of m-BG: 0, 5, 10, and 15 %. Glutaraldehyde 0.25 wt% (GA) was used as the cross-linker. The composites were characterized by scanning electron microscopy and the in vitro degradation of the films was studied by measuring the water uptake and weight loss. The drug release kinetics was quantified spectrophotometrically. The inhibition zone test and the plate count method were used to evaluate the antibacterial activity of the samples. Three staphylococcus strains were evaluated: Staphylococcus aureus ATCC6538, S. aureus ATCC29213, and Staphylococcus epidermidis ATCC12228. Cytotoxicity effects were evaluated through the MTT assay. The addition of m-BG to GS films showed no effects on the amount of water uptake, but led to an increase in the weight loss over time, even with m-BG content. The release rate of VC was also affected by the increasing concentration of m-BG in the composite films. However, the antibacterial effects of the composites were not improved by this modulation. All composites strongly inhibited staphylococcal cells with similar strength. On the other hand, liquid extracts from the composites resulted in cytotoxic effects on MG-63 osteoblastlike cells due to the presence of GA, but not to the concentration of VC or m-BG.
Research in Microbiology, Apr 30, 2009
Three Bacillus strains isolated from honey samples and bee gut were pre-selected for their in vit... more Three Bacillus strains isolated from honey samples and bee gut were pre-selected for their in vitro antimicrobial activity against Paenibacillus larvae and Ascosphaera apis, important honeybee pathogens. The analysis of their 16S rRNA sequences revealed that C4, M1 and G2III strains belong to the subtilis species. Surfactin synthesis was verified by IR spectroscopy and HPLC studies. Surfactin inhibited P. larvae but it failed to affect A. apis. Vegetative cells of P. larvae were affected as soon as they came in contact with the surfactin sample; two orders of magnitude less in log scale were recorded. Optimal surfactin production was observed in MEL medium, a broth with molasses as the only carbon source. Bacillus subtilis G2III strain exhibited the highest levels of surfactin synthesis in BHI and MEL broths: 1391 AU/ml and 2782 AU/ml, respectively. Since only A. apis inhibition was observed when cell suspensions were assayed, we suspect that there may be an antimycotic compound within cells. The co-production of surfactin and a fungicide by these strains might biologically control bee pathogens in apiculture.
Journal of Food Processing and Preservation, 2016
The adsorption of a commercial form of nisin, Nisaplin® (Npl) (Danisco), on montmorillonite (Mt),... more The adsorption of a commercial form of nisin, Nisaplin® (Npl) (Danisco), on montmorillonite (Mt), a natural inexpensive clay mineral accepted as food additive, was assayed. The intention was to develop food grade materials capable of releasing the peptide and avoiding negative interactions that affect nisin antimicrobial activity in food environments. A set of different Mt-Npl relation samples was prepared. The antimicrobial activity and the total organic carbon/total nitrogen (TOC/TN) content measured in nisin solutions after contact with the clay decreased as the amount of solid increased; thus, indicating the adsorption of the peptide on the support. Also, the Mt-Npl solids presented inhibitory activity against Enterococcus faecium C1. Additionally, Fourier Transform-Infrared Attenuated Total Reflectance spectroscopy (FT-IR-ATR) analysis of the Mt-Npl lyophilised systems showed that nisin was preferably adsorbed on Mt among Nisaplin® ingredients, suggesting a unique concentration and immobilization method for this antimicrobial peptide that could be applied in food preservation. Practical Applications Montmorillonite (Mt) is an inexpensive abundant natural clay characterized by a moderate cation exchange capacity with high surface area. Nisaplin® is a commercial form of nisin, a polypeptide bacteriocin active against several Gram-positive food spoilage and pathogen microorganisms. The increasing demand for fresh and natural food favors the application of biopreservatives such as nisin. However, the interaction of these antimicrobials with other food components reduces their inhibitory effect when directly introduced into food systems. Thus, alternatives for the inclusion of active biomolecules in foods are necessary. Since Mt is a potential food additive, its use as a nisin immobilization agent provides a strategy to protect and optimize the gradual peptide liberation. This immobilization approach does not only offer a simple, rapid, and low cost method for the concentration of nisin, but also provides a feasible alternative procedure for the introduction of this antimicrobial peptide in food complex systems.
Biomedical glasses, 2015
To prevent the high frequency of wound infections, anti-bacterial agents can be loaded onto compo... more To prevent the high frequency of wound infections, anti-bacterial agents can be loaded onto composites. In the present study, the antibiotic tetracycline hydrochloride (TC)was incorporated, for the first time, in collagen type I membranes coated with nano-sized SiO2-CaOP2O5 bioactive glass (n-BG) obtained by a sol-gel chemical route.Collagen membranes coated with n-BG were immersed in simulated body fluid (SBF) containing 0.25, 0.75 or 1.25 mg mL−1 of TC for 48 h at 37∘C following a coprecipitation method. The antibiotic was released in distilledwater at 37∘C for up to 72 h. The antibacterial activity of the composites was evaluated in vitro by the inhibition zone test and plate count method. Two different Staphylococcus aureus strains, S. aureus ATCC29213 and S. aureus ATCC25923, were exposed to the biomaterials. The results showed that the incorporation but not the release of TC was dependent on the initial concentration of TC in SBF. The biomaterials inhibited S. aureus growth, a...
Research Journal of Microbiology, 2006
Environmental Microbiology, 2004
Probiotics and antimicrobial proteins, 2014
Bacillus cereus is an endospore-forming, Gram-positive bacterium able to cause foodborne diseases... more Bacillus cereus is an endospore-forming, Gram-positive bacterium able to cause foodborne diseases. Lactic acid bacteria (LAB) are known for their ability to synthesize organic acids and bacteriocins, but the potential of these compounds against B. cereus has been scarcely documented in food models. The present study has examined the effect of the metabolites produced by Lactobacillus johnsonii CRL1647 and Enterococcus faecium SM21 on the viability of select B. cereus strains. Furthermore, the effect of E. faecium SM21 metabolites against B. cereus strains has also been investigated on a rice food model. L. johnsonii CRL1647 produced 128 mmol/L of lactic acid, 38 mmol/L of acetic acid and 0.3 mmol/L of phenyl-lactic acid. These organic acids reduced the number of vegetative cells and spores of the B. cereus strains tested. However, the antagonistic effect disappeared at pH 6.5. On the other hand, E. faecium SM21 produced only lactic and acetic acid (24.5 and 12.2 mmol/L, respectively...
Journal of food protection, 1999
Production of antagonistic compounds was studied in a strain of Enterococcus faecium isolated fro... more Production of antagonistic compounds was studied in a strain of Enterococcus faecium isolated from the intestinal tract of a free-ranging chicken. Production of lactic acid and a bacteriocin was observed in cultures of this bacterium, alone and in mixed culture fermentations with pathogenic Salmonella serotypes (i.e., Gallinarum, Pullorum, Enteritidis, and Typhimurium). Growth inhibition of these avian and human pathogens was observed after 4 h of incubation at 37 degrees C in CAm broth, a medium developed according to the nutrients present in chicken food. The antibacterial action was due to the combined effect of lactic acid and bacteriocin. Accumulation of these metabolites caused both a bacteriostatic and a bactericidal action against the gram-negative bacteria assayed.