Effects of microbial inoculants and amino acid production by-product on fermentation and chemical composition of sugarcane silages

The objective of this study was to evaluate the chemical composition, fermentation patterns and aerobic stability of sugarcane silages with addition of amino acid production (monosodium glutamate) by-product (APB) and microbial inoculants. Mature sugarcane was chopped and ensiled in laboratory silos (n = 4/treatment) without additives (control) and with APB (10 g/kg), Pioneer 1174® (PIO, 1.0 mg/kg, Lactobacillus plantarum + Streptoccoccus faecium, Pioneer), Lalsil Cana (2.0 mg/kg, Lactobacillus buchineri, Lallemand) or Mercosil Maís 11C33® (1.0 mg/kg, Lactobacillus buchineri + Lactobacillus plantarum + Streptoccoccus faecium, Timac Agro). Fresh silage and silage liquor samples were obtained to assess pH, chemical composition and organic acid concentrations. Silage temperature was recorded throughout seven days to evaluate aerobic stability. The addition of APB decreased lactic acid levels, increased pH and N-NH3 and did not alter ethanol, acetic and butyric acids concentrations or dry matter (DM) losses. Microbial inoculants enhanced acetic acid levels, although only Pioneer 1174® and Mercosil Maís 11C33® lowered ethanol, butyric acid and DM losses. The addition of APB increased CP content and did not modify DM, soluble carbohydrates contents or in vitro dry matter digestibility. Additives did not alter silage maximum temperature or temperature increasing rate; however, Pioneer 1174® and Mercosil Maís 11C33® increased the time elapsed to reach maximum temperature. Monosodium glutamate production by-product does not alter fermentation patterns or aerobic stability of sugarcane silages, whereas homofermentative bacteria can provide silages of good quality.

Gas-producing and spoilage potential of Enterobacteriaceae and lactic acid bacteria isolated from chilled vacuum-packaged beef

This study aimed to enumerate and identify lactic acid bacteria and Enterobacteriaceae from spoiled and nonspoiled chilled vacuum-packaged beef and determine their potential to cause blown pack spoilage. These microbial groups were also enumerated in nonspoiled samples and detected in abattoir samples. The potential of isolates to cause blown pack spoilage of vacuum-packaged beef stored at chilled temperature (4 degrees C) and abuse temperature (15 degrees C) was investigated. Populations of lactic acid bacteria in exudate of spoiled and nonspoiled samples were not significantly different (P > 0.05), whereas the number of lactic acid bacteria on the surface was significantly higher (P < 0.05) in spoiled samples as compared to nonspoiled samples. The population of Enterobacteriaceae species in exudate and on the surface of samples were significantly higher (P < 0.05) in spoiled packs in comparison with nonspoiled packs. Results of the deterioration potential showed that blown pack spoilage was noticeable after 7 days at 15 degrees C and after 6 weeks at 4 degrees C for samples inoculated with Hafnia alvei.

A preliminary study of the antibacterial potential of cetylpyridinium chloride in root canals infected by E. faecalis

The aim of this preliminary study was to verify the antibacterial potential of cetylpyridinium chloride (CPC) in root canals infected by Enterococcus faecalis. Forty human maxillary anterior teeth were prepared and inoculated with E. faecalis for 60 days. The teeth were randomly assigned to the following groups: 1: Root canal preparation (RCP) + 0.1% CPC with positive-pressure irrigation (PPI, Conventional, NaviTip®); 2: RCP + 0.2% CPC PPI; 3: RCP + 2.5% NaOCl PPI; 4: RCP + 2.5% NaOCl with negative-pressure irrigation system (NPI, EndoVac®); 5: Positive control; and 6: Negative control. Four teeth of each experimental group were evaluated by culture and 4 by scanning electron microscopy (SEM). In all teeth, the root canals were dried and filled with 17% EDTA (pH 7.2) for 3 min for smear layer removal. Samples from the infected root canals were collected and immersed in 7 mL of Letheen Broth (LB), followed by incubation at 37°C for 48 h. Bacterial growth was analyzed by turbidity of culture medium and then observed with a UV spectrophotometer. The irrigating solutions were further evaluated for antimicrobial effect by an agar diffusion test.The statistical data were treated by means, standard deviation, Kruskal-Wallis test and analysis of variance. Significance level was set at 5%. The results showed the presence of E. faecalis after root canal sanitization. The number of bacteria decreased after the use of CPC. In the agar diffusion test, CPC induced large microbial inhibition zones, similar to 2% chlorhexidine and large than 2.5% NaOCl. In conclusion, cetylpyridinium chloride showed antibacterial potential in endodontic infection with E. faecalis.

Potential of Bioactive Glass Particles of Different Size Ranges to Affect Bone Formation in Interproximal Periodontal Defects in Dogs

Background: The aim of this study was to compare the potential of bioactive glass particles of different size ranges to affect bone formation in periodontal defects, using the guided tissue regeneration model in dogs. Methods: In six dogs, 2-wall intrabony periodontal defects were surgically created and chronified on the mesial surfaces of mandibular third premolars and first molars bilaterally. After 1 month, each defect was randomly assigned to treatment with bioabsorbable membrane in association with bioactive glass with particle sizes between 300 and 355 mu m (group 1) or between 90 and 710 mu m (group 2), membrane alone (group 3), or negative control (group 4). The dogs were sacrificed 12 weeks after surgeries, and histomorphometric measurements were made of the areas of newly formed bone, new mineralized bone, and bioactive glass particle remnants. Results: With regard to the area of bioactive glass particle remnants, there was a statistically significant difference between groups 1 and 2, favoring group 1. There were greater areas of mineralized bone in groups 1 and 2 compared to groups 3 and 4 (P<0.05). Conclusion: The bioactive glass particles of small size range underwent faster resorption and substitution by new bone than the larger particles, and the use of bioactive glass particles favored the formation of mineralized bone. J Periodontol 2009;80:808-815.

Growth potential of Salmonella spp. and Listeria monocytogenes in nine types of ready-to-eat vegetables stored at variable temperature conditions during shelf-life

Growth potential (delta) is defined as the difference between the population of a microorganism at the end of shelf-life of specific food and its initial population. The determination of 6 of Salmonella and Listeria monocytogenes in RTE vegetables can be very useful to determine likely threats to food safety. However, little is known on the behavior of these microorganisms in several RTE vegetables. Therefore, the aim of this study was to determine the delta of both pathogens in nine different types of RTE vegetables (escarole, collard green, spinach, watercress, arugula, grated carrot, green salad, and mix for yakisoba) stored at refrigeration (7 degrees C) and abuse temperature (15 degrees C). The population of aerobic microorganisms and lactic acid bacteria, including those showing antimicrobial activity has been also determined. Results indicated that L monocytogenes was able to grow (delta >= 0.5 log(10)) in more storage conditions and vegetables than Salmonella. Both microorganisms were inhibited in carrots, although a more pronounced effect has been observed against L monocytogenes. The highest 5 values were obtained when the RTE vegetables were stored 15 degrees C/6 days in collard greens (delta=3.3) and arugula (delta=3.2) (L monocytogenes) and arugula (delta=4.1) and escarole (delta=2.8) (Salmonella). In most vegetables and storage conditions studied, the counts of total aerobic microorganisms raised significantly independent of the temperature of storage (p<0.05). Counts of lactic acid bacteria were higher in vegetables partially or fully stored at abuse temperature with recovery of isolates showing antimicrobial activity. In conclusion, the results of this study show that Salmonella and L monocytogenes may grow and reach high populations in RTE vegetables depending on storage conditions and the definition of effective intervention strategies are needed to control their growth in these products. (C) 2012 Elsevier B.V. All rights reserved.

Bacteriocinogenic and virulence potential of Enterococcus isolates obtained from raw milk and cheese

Aims To provide molecular and phenotypical characterization of Enterococcus isolates obtained from raw milk and cheese, regarding their bacteriocinogenic and virulence activity. Methods and Results Forty-three bacteriocinogenic enterococci isolates were identified by 16s rDNA, fingerprinted by RAPD-PCR analysis and tested by PCR for the presence of genes for lantibiotics (lanM, lanB and lanC) and enterocins (entA, entB, entP, entL50AB and entAS48) and by phenotypical methods for bacteriocin production and inhibitory spectrum. Also, the virulence of the isolates was evaluated by PCR for genes gelE, hyl, asa1, esp, cylA, efaA, ace, vanA, vanB, hdc1, hdc2, tdc and odc and by phenotypical tests for gelatinase, lipase, DNAse and a- and beta-haemolysis. Most isolates (93.0%) harboured at least one lantibiotic or enterocin gene and were positive for several tested virulence genes, mainly asa1 (100%), gelE (93.0%) and efaA (83.7%). 53.5% of the isolates presented beta-haemolysis. Conclusions Enterococcus spp. isolates presented an interesting potential application for food preservation because of bacteriocin production; however, virulence-related genes were identified in all RAPD profiles. Significance and Impact of the Study The study demonstrated the contradictory characteristics of the tested Enterococcus isolates: they presented a good potential for application in food biopreservation but contained several virulence factors.

Analysis of the protective potential of antigens released by Leishmania (Viannia) shawi promastigotes

Leishmania (Viannia) shawi causes cutaneous lesions in humans. Parasite antigens conferring significant protection against American tegumentar leishmaniosis (ATL) might be important for the development of effective vaccine. Therefore, this work evaluates the protective effect of antigenic fractions released by L. shawi. Antigens released by promastigotes to culture medium were concentrated and isolated by SDS-PAGE. The three main fractions LsPass1 (>75 kDa), LsPass2 (75-50 kDa) and LsPass3 (<50 kDa) were electro-eluted according with their molecular mass. Immunized BALB/c mice were challenged with L. shawi promastigotes and the course of infection monitored during 5 weeks. LsPass1-challenged mice showed no protection, however, a strong degree of protection associated to smaller lesions and high expression of IFN-gamma and TNF-alpha by CD4(+) T, CD8(+) T and double negative CD4CD8 cells was achieved in LsPass3-challenged mice. Furthermore, LsPass2-challenged mice showed an intermediated degree of protection associated to high levels of IFN-gamma, IL-4 and IL-10 mRNA. In spite of increased expression of IFN-gamma and TNF-alpha, high amounts of IL-4 and IL-10 mRNA were also detected in LsPass3-challenged mice indicating a possible contribution of these cytokines for the persistence of a residual number of parasites that may be important in inducing long-lasting immunity. Therefore, LsPass3 seems to be an interesting alternative that should be considered in the development of an effective vaccine against ATL.

Erosive potential of different types of grape juices

The purpose of the present study was to evaluate the erosive potential of different types (concentrated and powdered) and commercial brands of industrialised grape juices. The pH of all five fruit drinks was measured at two time points: immediately after preparation and 24 hours later. Sixty specimens of bovine enamel were randomly allocated and immersed in different types of grape juice (n = 10) for 10 minutes four times a day for fifteen days. The enamel alteration was analysed using surface Knoop microhardness (KHN) and surface roughness (R-a) tests at baseline and on the 5th, 10th and 15th days of the experiment. Two way ANOVA, Tukey's post hoc and Pearson's correlation tests were used for statistical analysis (alpha = 5%). The grape juices presented pH values ranging from 2.9 to 3.5. All of the tested juices promoted significant enamel mineral loss (p < 0.05) on the first evaluation (5th day of immersion) and produced a significant increase in the mean roughness from the 10th day on when compared to the control group (p < 0.05). By the 15th day, all of the beverages had produced surface roughnesses that were significantly higher than that of the control group. The results suggest that all grape juices, regardless of their commercial presentation, present erosive potential.

Iron supplementation reduces the erosive potential of a cola drink on enamel and dentin in situ

Iron has been suggested to reduce the erosive potential of cola drinks in vitro. Objective: The aim of this study was to evaluate in situ the effect of ferrous sulfate supplementation on the inhibition of the erosion caused by a cola drink. Material and Methods: Ten adult volunteers participated in a crossover protocol conducted in two phases of 5 days, separated by a washout period of 7 days. In each phase, they wore palatal devices containing two human enamel and two human dentin blocks. The volunteers immersed the devices for 5 min in 150 mL of cola drink (Coca-Cola (TM), pH 2.6), containing ferrous sulfate (10 mmol/L) or not (control), 4 times per day. The effect of ferrous sulfate on the inhibition of erosion was evaluated by profilometry (wear). Data were analyzed by paired t tests (p<0.05). Results: The mean wear (+/- se) was significantly reduced in the presence of ferrous sulfate, both for enamel (control: 5.8 +/- 1.0 mu m; ferrous sulfate: 2.8 +/- 0.6 mu m) and dentin (control: 4.8 +/- 0.8 mu m; ferrous sulfate: 1.7 +/- 0.7 mu m). Conclusions: The supplementation of cola drinks with ferrous sulfate can be a good alternative for the reduction of their erosive potential. Additional studies should be done to test if lower ferrous sulfate concentrations can also have a protective effect as well as the combination of ferrous sulfate with other ions.

COMPARISON OF DIFFERENT PROTOCOLS FOR THE EXTRACTION OF MICROBIAL DNA FROM REEF CORALS

This study aimed to test different protocols for the extraction of microbial DNA from the coral Mussismilia harttii. Four different commercial kits were tested, three of them based on methods for DNA extraction from soil (FastDNA SPIN Kit for soil, MP Bio, PowerSoil DNA Isolation Kit, MoBio, and ZR Soil Microbe DNA Kit, Zymo Research) and one kit for DNA extraction from plants (UltraClean Plant DNA Isolation Kit, MoBio). Five polyps of the same colony of M. harttii were macerated and aliquots were submitted to DNA extraction by the different kits. After extraction, the DNA was quantified and PCR-DGGE was used to study the molecular fingerprint of Bacteria and Eukarya. Among the four kits tested, the ZR Soil Microbe DNA Kit was the most efficient with respect to the amount of DNA extracted, yielding about three times more DNA than the other kits. Also, we observed a higher number and intensities of DGGE bands for both Bacteria and Eukarya with the same kit. Considering these results, we suggested that the ZR Soil Microbe DNA Kit is the best adapted for the study of the microbial communities of corals.

In situ Evaluation of the Erosive Potential of Orange Juice Modified by Food Additives

The aim of this study was to evaluate the erosive potential of orange juice modified with food-approved additives: 0.4 g/l of calcium (Ca) from calcium lactate pentahydrate, 0.2 g/l of linear sodium polyphosphate (LPP) or their combination (Ca+LPP) were added to a commercially available orange juice (negative control, C-). A commercially available calcium-modified orange juice (1.6 g/l of calcium) was the positive control (C+). These juices were tested using a short-term erosion in situ model, consisting of a five-phase, single-blind crossover clinical trial involving 10 subjects. In each phase, subjects inserted custom-made palatal appliances containing 8 bovine enamel specimens in the mouth and performed erosive challenges for a total of 0 (control), 10, 20, and 30 min. Two specimens were randomly removed from the appliances after each challenge period. Enamel surface microhardness was measured before and after the clinical phase and the percentage of surface microhardness change (%SMC) was determined. Before the procedures, in each phase, the subjects performed a taste test, where the juice assigned to that phase was blindly compared to C-. Overall, C+ showed the lowest %SMC, being the least erosive solution (p < 0.05), followed by Ca+LPP and Ca, which did not differ from each other (p > 0.05). LPP and C- were the most erosive solutions (p <0.05). Taste differences were higher for C+ (5/10 subjects) and Ca (4/10 subjects), but detectable in all groups, including C- (2/10 subjects). Calcium reduced the erosive potential of the orange juice, while no protection was observed for LPP. Copyright (C) 2012 S. Karger AG, Basel

Potential of a neutrino detector in the ANDES underground laboratory for geophysics and astrophysics of neutrinos

The construction of the Agua Negra tunnels that will link Argentina and Chile under the Andes, the world's longest mountain range, opens the possibility of building the first deep underground laboratory in the Southern Hemisphere. This laboratory has the acronym ANDES (Agua Negra Deep Experiment Site) and its overburden could be as large as similar to 1.7 km of rock, or 4500 mwe, providing an excellent low background environment to study physics of rare events like the ones induced by neutrinos and/or dark matter. In this paper we investigate the physics potential of a few kiloton size liquid scintillator detector, which could be constructed in the ANDES laboratory as one of its possible scientific programs. In particular, we evaluate the impact of such a detector for the studies of geoneutrinos and Galactic supernova neutrinos, assuming a fiducial volume of 3 kilotons as a reference size. We emphasize the complementary roles of such a detector to the ones of the Northern Hemisphere neutrino facilities, given the advantages of its geographical location.

Molecular Analysis of the Differentiation Potential of Murine Mesenchymal Stem Cells from Tissues of Endodermal or Mesodermal Origin

Mesenchymal stem cells (MSCs) have received great attention due to their remarkable regenerative, angiogenic, antiapoptotic, and immunosuppressive properties. Although conventionally isolated from the bone marrow, they are known to exist in all tissues and organs, raising the question on whether they are identical cell populations or have important differences at the molecular level. To better understand the relationship between MSCs residing in different tissues, we analyzed the expression of genes related to pluripotency (SOX2 and OCT-4) and to adipogenic (C/EBP and ADIPOR1), osteogenic (OMD and ALP), and chondrogenic (COL10A1 and TRPV4) differentiation in cultures derived from murine endodermal (lung) and mesodermal (adipose) tissue maintained in different conditions. MSCs were isolated from lungs (L-MSCs) and inguinal adipose tissue (A-MSCs) and cultured in normal conditions, in overconfluence or in inductive medium for osteogenic, adipogenic, or chondrogenic differentiation. Cultures were characterized for morphology, immunophenotype, and by quantitative real-time reverse transcription-polymerase chain reaction for expression of pluripotency genes or markers of differentiation. Bone marrow-derived MSCs were also analyzed for comparison of these parameters. L-MSCs and A-MSCs exhibited the typical morphology, immunophenotype, and proliferation and differentiation pattern of MSCs. The analysis of gene expression showed a higher potential of adipose tissue-derived MSCs toward the osteogenic pathway and of lung-derived MSCs to chondrogenic differentiation, representing an important contribution for the definition of the type of cell to be used in clinical trials of cell therapy and tissue engineering.

EVALUATION OF MICROBIAL GROWTH ON SINGLE-USE VITRECTOMY PROBES REPROCESSED IN HEALTHCARE PRACTICE

The aim of this study was to evaluate the microbial growth on single-use vitrectomy probes reprocessed in healthcare practice. We investigated nine vitrectomy probes that had been reused and reprocessed using different methods. The samples were sectioned, individually, in portions of 3.5 cm, totaling 979 sampling units (extensions, connectors and vitrectomy cutters), which were inoculated in culture medium and incubated at 37 C for 14 days. The results showed microbial growth on 57 (5.8%) sample units, 25 of which had been sterilized using ethylene oxide, 16 by hydrogen peroxide plasma, and 16 by low-temperature steam and formaldehyde. Seventeen microbial species were identified. The most prevalent were: Micrococcus spp., coagulase-negative Staphylococcus, Pseudomonas spp., and Bacillus subtilis. The reuse of single-use vitrectomy probes was shown to be unsafe, therefore this practice is not recommended.

In Vitro Evaluation of the Probiotic Potential of Bacteriocin Producer Lactobacillus sakei 1

Lactobacillus sakei 1 is a food isolate that produces a heat-stable antimicrobial peptide (sakacin 1, a class ha bacteriocin) inhibitory to the opportunistic pathogen Listeria monocytogenes. Bacterial isolates with antimicrobial activity may be useful for food biopreservation and also for developing probiotics. To evaluate the probiotic potential of L. sakei I, it was tested for (i) in vitro gastric resistance (with synthetic gastric juice adjusted to pH 2.0, 2.5, or 3.0); (ii) survival and bacteriocin production in the presence of bile salts and commercial prebiotics (inulin and oligofructose); (iii) adhesion to Caco-2 cells; and (iv) effect on the adhesion of L. monocytogenes to Caco-2 cells and invasion of these cells by the organism. The results showed that L. sakei I survival in gastric environment varied according to pH, with the maximum survival achieved at pH 3.0, despite a 4-log reduction of the population after 3 h. Regarding the bile salt tolerance and influence of prebiotics, it was observed that L. sakei 1 survival rates were similar (P > 0.05) for all de Man Rogosa Shame (MRS) broth formulations when tests were done after 4 h of incubation. However, after incubation for 24 h, the survival of L. sakei 1 in MRS broth was reduced by 1.8 log (P < 0.001), when glucose was replaced by either inulin or oligofructose (without Oxgall). L. sakei 1 was unable to deconjugate bile salts, and there was a significant decrease (1.4 log) of the L. sakei 1 population in regular MRS broth plus Oxgall (P < 0.05). In spite of this, tolerance levels of L. sakei 1 to bile salts were similar in regular MRS broth and in MRS broth with oligofructose. Lower bacteriocin production was observed in MRS broth when inulin (3,200 AU/ml) or oligofructose (2,400 AU/ml) was used instead of glucose (6,400 AU/ml). L. sakei I adhered to Caco-2 cells, and its cell-free pH-neutralized supernatant containing sakacin I led to a significant reduction of in vitro listerial invasion of human intestinal Caco-2 cells.