Evaluation of different selective media for enumeration of probiotic micro-organisms in combination with yogurt starter cultures in fermented milk

The aim of this study was to assess selective plating methodologies for the enumeration and identification of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus, Lactobacillus rhamnosus and Bifidobacterium animalis ssp. lactis in fermented milks. Seven agar media (MRS with added sorbitol, clindamycin or vancomycin, acidified MRS, RCA with added aniline blue and dicloxacilin, M17 and ST) were evaluated. The results showed that RCA dicloxacilin agar was suitable for the selective enumeration of B. animalis ssp. lactis in fermented milk. Either MRS (acidified) or M17 agar could be used for enumeration of L. delbrueckii ssp. bulgaricus and S. thermophilus, respectively. MRS media containing antibiotics were effective for the enumeration of the probiotic organisms (L. rhamnosus and L. acidophilus) inoculated in fermented milks.

Evaluation of rhamnolipid and surfactin to reduce the adhesion and remove biofilms of individual and mixed cultures of food pathogenic bacteria

Biofilms represent a great concern for food industry, since they can be a source of persistent contamination leading to food spoilage and to the transmission of diseases. To avoid the adhesion of bacteria and the formation of biofilms, an alternative is the pre-conditioning of surfaces using biosurfactants, microbial compounds that can modify the physicochemical properties of surfaces changing bacterial interactions and consequently adhesion. Different concentrations of the biosurfactants, surfactin from Bacillus subtilis and rhamnolipids from Pseudomonas aeruginosa, were evaluated to reduce the adhesion and to disrupt biofilms of food-borne pathogenic bacteria. Individual cultures and mixed cultures of Staphylococcus aureus, Listeria monocytogenes and Salmonella Enteritidis were studied using polystyrene as the model surface. The pre-conditioning with surfactin 0.25% reduced by 42.0% the adhesion of L monocytogenes and S. Enteritidis, whereas the treatment using rhamnolipids 1.0% reduced by 57.8% adhesion of L monocytogenes and by 67.8% adhesion of S. aureus to polystyrene.Biosurfactants were less effective to avoid adhesion of mixed cultures of the bacteria when compared with individual cultures. After 2 h contact with surfactin at 0.1% concentration, the pre-formed biofilms of S. aureus were reduced by 63.7%, L. monocytogenesby 95.9%, S. Enteritidis by 35.5% and the mixed culture biofilm by 58.5%. The rhamnolipids at 0.25% concentration removed 58.5% the biofilm of S. aureus, 26.5% of L monocytogenes, 23.0% of S. Enteritidis and 24.0% the mixed culture after 2 h contact. In general, the increase in concentration of biosurfactants and in the time of contact decreased biofilm removal percentage. These results suggest that surfactin and rhamnolipids can be explored to control the attachment and to disrupt biofilms of individual and mixed cultures of the food-borne pathogens. (C) 2011 Elsevier Ltd. All rights reserved.

Evaluation of the micro-hardness and fracture toughness of amorphous and partially crystallized 3CaO center dot P2O5-SiO2-MgO bioglasses

In this work, the effect of the indentation load on the results of hardness and fracture toughness, determined by Vickers micro-hardness measurements, of some glasses and glass-ceramics has been investigated. Furthermore, in order to verify the effect of crystallinity on the results, glasses of composition 52.75 wt.% 3CaO center dot P2O5, 30 wt.% SiO2 and 17.25 wt.% MgO were fused at 1600 degrees C for 4 h and annealed at 700 degrees C for 2h, and further heat-treated at 700, 775, 800 and 900 degrees C for 4h. The obtained materials were analyzed by high resolution X-ray diffraction, HRXRD, to determine the crystallization degree in function of the heat-treatment temperature. The hardness of the different specimens was determined by Vickers' micro-hardness measurements under various loads. It has been observed that with increasing crystallization of the materials their hardness increased. Furthermore, it has been possible to verify the so-called indentation size effect (ISE), i.e. hardness decreases as the indentation depth, under higher loads, increases. This effect has been more pronounced in the glass-ceramic samples. Fracture toughness has been determined by the crack length induced by the Vickers indentations and relating them to the applied loads. Glass materials presented a fracture pattern with characteristics of cleavage, forming cracks of the half-penny shaped type, while the glass-ceramic materials exhibited crack bridging effects and Palmqvist type cracks. (C) 2011 Elsevier B.V. All rights reserved.

Micro-structural and compositional variations of hydrothermal epidote-group minerals from a peralkaline granite, Corupá Pluton, Graciosa Province, South Brazil, and their petrological implications

Epidote-group minerals, together with albite, quartz, fluorite, Al-poor and Fe-rich phyllosilicates, zircon, and minor oxides and sulphides, are typical hydrothermal phases in peralkaline alkali-feldspar granites from the Corupá Pluton, Graciosa Province, South Brazil. The epidote-group minerals occur as single crystals and as aggregates filling in rock interstices and miarolitic cavities. They display complex recurrent zoning patterns with an internal zone of ferriallanite-(Ce), followed by allanite-(Ce), then epidote-ferriepidote, and an external zone with allanite-(Ce), with sharp limits, as shown in BSE and X-ray images. REE patterns show decreasing fractionation degrees of LREE over HREE from ferriallanite to epidote. The most external allanite is enriched in MREE. LA-ICP-MS data indicate that ferriallanite is enriched (>10-fold) in Ti, Sr and Ga, and depleted in Mg, Rb, Th and Zr relative to the host granite. Allanite has lower Ga and Mn and higher Zr, Nb and U contents as compared to ferriallanite, while epidote is enriched in Sr, U and depleted in Pb, Zr, Hf, Ti and Ga. The formation of these minerals is related to the variable concentrations of HFSE, Ca, Al, Fe and F in fluids remaining from magmatic crystallization, in an oxidizing environment, close to the HM buffer. L-MREE were in part released by the alteration of chevkinite, their main primary repository in the host rocks.

Distribution and stability of aflatoxin M-1 during processing and storage of Minas Frescal cheese

Aflatoxin M-1 (AFM(1)) is a hepatocarcinogen found in milk of animals that have consumed feeds with aflatoxin B-1. The carry-over of AFM(1) from milk to Minas Frescal cheese produced with or without starter cultures was determined. 40 L of milk were divided into 10 L each and assigned to the following treatments for cheese manufacture: 0.250 rig AFM(1) mL(-1), 0.500 rig AFM(1) mL(-1), 0.250 ng AFM(1) mL(-1) + starter, 0.500 ng AFM(1) mL(-1) + starter. Quantification of AFM(1) was achieved by high performance liquid chromatography. The carry-over of AFM(1) from milk to cheese ranged from 30.64% to 42.26%. There was no effect of storage time on AFM(1). Milk with AFM(1) in levels studied may concentrate the toxin in Minas Frescal cheese, but at concentrations below the Brazilian tolerance limit. The addition of starter cultures did not influence concentration or stability of the AFM(1) in cheese over 30 days storage. (C) 2011 Elsevier Ltd. All rights reserved.

Organic milk improves Bifidobacterium lactis counts and bioactive fatty acids contents in fermented milk

In functional dairy products, polyunsaturated fatty acids such as, conjugated linoleic acid (CLA) and alpha-linolenic acid (ALA) have been highlighted for their benefits related to prevention of some chronic diseases. In order to study the effect of type of milk (conventional vs. organic, characterized by a specific fatty acid composition), Bifidobacterium animalis subsp. lactis (BB12, B94, BL04 and HN019) counts, acidification activity and chemical composition (pH, lactose, lactic acid contents and fatty acids profile) were investigated before fermentation and after 24 h of products stored at 4 degrees C. Organic and conventional milk influenced acidification performance and bacteria counts, which was strain-dependent. Higher counts of BB12 were observed in organic milk, whereas superior counts of BL04 were found in conventional milk. Organic fermented milk showed lower levels in saturated fatty acids (FA) and higher in monounsaturated FA contents. Similarly, among bioactive FA, organic fermented milks have higher amounts of trans vaccenic acid (TVA-C18:1t), conjugated linoleic acid (CLA) and slightly higher contents of alpha-linoleic acid (ALA). (C) 2012 Elsevier Ltd. All rights reserved.

Probiotic yogurts manufactured with increased glucose oxidase levels: Postacidification, proteolytic patterns, survival of probiotic microorganisms, production of organic acid and aroma compounds

We investigated the effect of increased glucose oxidase concentration as a technological option to decrease oxidative stress during the processing of probiotic yogurts. Probiotic yogurts were produced with increased concentrations of glucose oxidase (0, 250, 500, 750, or 1,000 mg/kg) and submitted to physicochemical and microbiological analysis at 1, 15, and 30 d of refrigerated storage. Higher concentrations of glucose oxidase (750 and 1,000 mg/kg) and a longer storage time were found to have an influence on the characteristics of the probiotic yogurt, contributing to more extensive post-acidification, an increase in the dissolved oxygen level, and higher proteolysis. In addition, increased production of aroma compounds (diacetyl and acetaldehyde) and organic acids (mainly lactic acid) and a decrease in the probiotic bacteria count were reported. The use of glucose oxidase was a feasible option to minimize oxidative stress in probiotic yogurts. However, supplementation with excessive amounts of the enzyme may be ineffective, because insufficient substrate (glucose) is present for its action. Consumer tests should be performed to evaluate changes in the sensory attributes of the probiotic yogurts with increased supplementation of glucose oxidase. In addition, packaging systems with different permeability to oxygen should be evaluated.

Minimal alterations on the enamel surface by micro-abrasion: in vitro roughness and wear assessments

Objective: To evaluate the in vitro changes on the enamel surface after a micro-abrasion treatment promoted by different products. Material and Methods: Fifty (50) fragments of bovine enamel (15 mm × 5 mm) were randomly assigned to five groups (n=10) according to the product utilized: G1 (control)= silicone polisher (TDV), G2= 37% phosphoric acid (3M/ESPE) + pumice stone (SS White), G3= Micropol (DMC Equipment), G4= Opalustre (Ultradent) and G5= Whiteness RM (FGM Dental Products). Roughness and wear were the responsible variables used to analyze these surfaces in four stages: baseline, 60 s and 120 s after the micro-abrasion and after polishing, using a Hommel Tester T1000 device. After the tests, a normal distribution of data was verified, with repeated ANOVA analyses (p?0.05) which were used to compare each product in different stages. One-way ANOVA and Tukey tests were applied for individual comparisons between the products in each stage (p?0.05). Results: Means and standard deviations of roughness and wear (µm) after all the promoted stages were: G1=7.26(1.81)/13.16(2.67), G2=2.02(0.62)/37.44(3.33), G3=1.81(0.91)/34.93(6.92), G4=1.92(0.29)/38.42(0.65) and G5=1.98(0.53)/33.45(2.66). At 60 seconds, all products tended to produce less surface roughness with a variable gradual decrease over time. After polishing, there were no statistically significant differences between the groups, except for G1. Independent of the product utilized, the enamel wear occurred after the micro-abrasion. Conclusions: In this in vitro study, enamel micro-abrasion presented itself as a conservative approach, regardless of the type of the paste compound utilized. These products promoted minor roughness alterations and minimal wear. The use of phosphoric acid and pumice stone showed similar results to commercial products for the micro-abrasion with regard to the surface roughness and wear.

Lethal effects of abamectin on the aquatic organisms Daphnia similis, Chironomus xanthus and Danio rerio

Abamectin is used as an acaricide and insecticide for fruits, vegetables and ornamental plants, as well as a parasiticide for animals. One of the major problems of applying pesticides to crops is the likelihood of contaminating aquatic ecosystems by drift or runoff. Therefore, toxicity tests in the laboratory are important tools to predict the effects of chemical substances in aquatic ecosystems. The aim of this study was to assess the potential hazards of abamectin to the freshwater biota and consequently the possible losses of ecological services in contaminated water bodies. For this purpose, we identified the toxicity of abamectin on daphnids, insects and fish. Abamectin was highly toxic, with an EC50 48 h for Daphnia similis of 5.1 ng L-1, LC50 96 h for Chironomus xanthus of 2.67 mu g L-1 and LC50 48 h for Danio rerio of 33 mu g L-1. (C) 2011 Elsevier Ltd. All rights reserved.

A palaeobiologist's guide to 'virtual' micro-CT preparation

This paper provides a brief but comprehensive guide to creating, preparing and dissecting a 'virtual' fossil, using a worked example to demonstrate some standard data processing techniques. Computed tomography (CT) is a 3D imaging modality for producing 'virtual' models of an object on a computer. In the last decade, CT technology has greatly improved, allowing bigger and denser objects to be scanned increasingly rapidly. The technique has now reached a stage where systems can facilitate large-scale, non-destructive comparative studies of extinct fossils and their living relatives. Consequently the main limiting factor in CT-based analyses is no longer scanning, but the hurdles of data processing (see disclaimer). The latter comprises the techniques required to convert a 3D CT volume (stack of digital slices) into a virtual image of the fossil that can be prepared (separated) from the matrix and 'dissected' into its anatomical parts. This technique can be applied to specimens or part of specimens embedded in the rock matrix that until now have been otherwise impossible to visualise. This paper presents a suggested workflow explaining the steps required, using as example a fossil tooth of Sphenacanthus hybodoides (Egerton), a shark from the Late Carboniferous of England. The original NHMUK copyrighted CT slice stack can be downloaded for practice of the described techniques, which include segmentation, rendering, movie animation, stereo-anaglyphy, data storage and dissemination. Fragile, rare specimens and type materials in university and museum collections can therefore be virtually processed for a variety of purposes, including virtual loans, website illustrations, publications and digital collections. Micro-CT and other 3D imaging techniques are increasingly utilized to facilitate data sharing among scientists and on education and outreach projects. Hence there is the potential to usher in a new era of global scientific collaboration and public communication using specimens in museum collections.

PHYSICO-CHEMICAL EVALUATION OF AN EFFLUENT TREATED IN ANAEROBIC BIODIGESTER REGARDING ITS EFFICIENCE AND APPLICATION AS FERTILIZER

PHYSICO-CHEMICAL EVALUATION OF AN EFFLUENT TREATED IN ANAEROBIC BIODIGESTER REGARDING ITS EFFICIENCE AND APPLICATION AS FERTILIZER. The use of biodigester for basic and environmental sanitation has large demand in Brazil. A biodigester was built to treat conjunctly the human and pig feces and urine, regarding to its future application in rural small towns. The results show that the biodigester can reduce 90% of COD and BOD and, up to 99.99% of thermotolerant coliforms. The treated effluent has variable quantities of macro- and micro-nutrients; and organic matter. However, the concentration variability of the nutrients makes difficult a dosed application into soil. The soluble salts (mainly as Na+ form) make necessary a controlled use to avoid environmental degradation.

Interferon-gamma and interleukin-10 production by mononuclear cells from patients with advanced head and neck cancer

OBJECTIVE: This study aims to evaluate the production of interferon-gamma and interleukin-10 by stimulated peripheral blood mononuclear cells isolated from patients with supraglottic laryngeal cancer before and after surgical treatment. METHODS: Fourteen patients with advanced supraglottic laryngeal cancer were studied. Cultures of peripheral blood mononuclear cells isolated during the preoperative and late postoperative periods were stimulated with concanavalin A and Bacille Calmette-Guerin, and the supernatant concentrations of interferon-gamma and interleukin-10 were measured. RESULTS: For non-stimulated cultures, the interferon-gamma levels produced by the preoperative period and the late postoperative period cultures were lower than the levels produced by the control group cultures. The interferon-gamma levels after stimulation with concanavalin A were higher in the late postoperative period cultures than in the preoperative evaluation cultures. Stimulation with Bacille Calmette-Guerin led to the production of similar levels of interferon-gamma and interleukin-10 by all cultures; thus, stimulation increased the levels of interferon-gamma produced by both the preoperative and postoperative cultures relative to the levels produced by the corresponding unstimulated cultures. CONCLUSION: Patients with advanced supraglottic laryngeal cancer exhibit an in vitro deficiency in interferongamma secretion by mononuclear cells. Stimulated cells seem to recover this function during the postoperative period.

Dynamics of free and H-3-labelled glutamine concentrations during zygotic and somatic embryogenesis of Feijoa [Acca sellowiana (O. Berg.) Burret]

Amino acids play fundamental roles in plant morphogenesis. Among sources of organic nitrogen (N), glutamine has frequently been used during the establishment and maintenance of cell and tissue cultures. The aim of this study was analyse endogenous levels of glutamine during somatic and zygotic embryogenesis of Acca sellowiana (Feijoa or pineapple guava). The in vitro absorption of H-3-labelled glutamine was investigated. Zygotic embryos and embryogenic cultures (EC) were evaluated at 30 d and 70 d after explant inoculation onto the medium. Endogenous levels of glutamine were similar during zygotic and somatic embryogenesis, and showed a gradual decline until day-24 in culture. The highest rates of H-3-labelled glutamine uptake were observed during the first 2 h of incubation, resulting in values of 6.29 mu mol g(-1) fresh weight (FW) for zygotic embryos, 14.43 mu mol g(-1) FW for EC after 30 d, and 13.85 mu mol g(-1) FW for EC after 70 d. These results showed that the decreased levels of glutamine observed during the initial phase of development may be related to de novo protein synthesis and mobilisation during embryo maturation. The absorption of glutamine in the first 2 h of incubation also emphasises its involvement as an important source of N during morphogenesis of somatic and zygotic embryos.

Cloning and characterisation of a novel chromosome end repeat enriched with homopolymeric (dA)/(dT) DNA in Rhynchosciara americana (Diptera: Sciaridae)

Short tandem DNA repeats and telomerase compose the telomere structure in the vast majority of eukaryotic organisms. However, such a conserved organisation has not been found in dipterans. While telomeric DNA in Drosophila is composed of specific retrotransposons, complex terminal tandem repeats are present in chromosomes of Anopheles and chironomid species. In the sciarid Rhynchosciara americana, short repeats (16 and 22 bp long) tandemly arrayed seem to reach chromosome ends. Moreover, in situ hybridisation data using homopolymeric RNA probes suggested in this species the existence of a third putative chromosome end repeat enriched with (dA).(dT) homopolymers. In this work, chromosome micro-dissection and PCR primed by homopolymeric primers were employed to clone these repeats. Named T-14 and 93 % AT-rich, the repetitive unit is 14 bp long and appears organised in tandem arrays. It is localised in five non-centromeric ends and in four interstitial bands of R. americana chromosomes. To date, T-14 is the shortest repeat that has been characterised in chromosome ends of dipterans. As observed for short tandem repeats identified previously in chromosome ends of R. americana, the T-14 probe hybridised to bridges connecting non-homologous polytene chromosome ends, indicative of close association of T-14 repeats with the very end of the chromosomes. The results of this work suggest that R. americana represents an additional example of organism provided with more than one DNA sequence that is able to reach chromosome termini.

Inhibition of Aurora kinases enhances chemosensitivity to temozolomide and causes radiosensitization in glioblastoma cells

Glioblastoma remains one of the most devastating human malignancies, and despite therapeutic advances, there are no drugs that significantly improve the patient survival. Altered expression of the Aurora kinases was found in different malignancies, and their inhibition has been studied in cancer therapy. In this study, we analyzed the expression of Aurora A and Aurora B in glioblastoma samples and also analyzed whether the effects of Aurora kinase inhibition were associated with temozolomide or not on cell lines and primary cultures of glioblastoma. RT-PCR assays were used to determine the mRNA expression in glioblastoma tumor samples and in the cell lines. Cell proliferation was measured by XTT assay, and apoptosis was determined by flow cytometry. Drug combination analyses were made based in Chou-Talalay method. Gamma radiation for clonogenic survival used the doses of 2, 4 and 6 Gy. Changes in Aurora B level were assessed by Western blot analysis. Aurora A and B were expressed in glioblastoma samples as well as in the glioblastoma cell lines (n = 6). Moreover, ZM447439, a selective Aurora kinase inhibitor, decreased the proliferation separately and synergistically with temozolomide in primary cultures and cell lines of glioblastoma. ZM also enhanced the effects of radiation on the two cell lines studied (U343 and U251), mainly when associated with TMZ in U343 cells. Treatment with ZM induced apoptotic cell death and diminished Aurora B protein level. These data suggest that Aurora kinase inhibition may be a target for glioblastoma treatment and could be used as adjuvant to chemo- and radiotherapy.