993 resultados para staining methods


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Hefen der Gattungen Brettanomyces/Dekkera sind in der Produktion von fermentierten Getränken, insbesondere in der Bier-, Sekt- und Weinherstellung bekannt. Sie können als Schädlingshefen insbesondere durch die Bildung von charakteristischen Sekundärmetaboliten zu einer negativen geschmacklichen Veränderung des Getränks führen. Aufgrund ihres langsamen Wachstums werden diese Hefen bei Routineanalysen mit konventionellen Kultivierungsmethoden leicht übersehen. Ein schneller und eindeutiger Nachweis von Brettanomyces/Dekkera-Hefen ist bis heute problematisch. In der vorliegenden Arbeit wurde eine Methode zur sicheren Detektion und Identifizierung aller fünf bekannten Spezies dieser Gattungen entwickelt. Die Fluoreszenz in situ Hybridisierung (FISH) mit Cy3-markierten DNA-Sonden ermöglichte einen direkten mikroskopischen Nachweis dieser Mikroorganismen in der Untersuchungsprobe. Im Hinblick auf die Generierung Art-spezifischer Sonden wurden die ribosomalen Gen-Cluster der verschiedenen Spezies hinsichtlich potentieller Zielregionen analysiert. Eine signifikante Steigerung des Sonden-vermittelten Fluoreszenz-Signals konnte durch die Anwendung eines neuen Sonden-Konzepts (Gemeinschafts-Sonden) auf hochvariable Bereichen der 26S rRNAs, unter Berücksichtigung ihrer Sekundärstrukturen, realisiert werden. Die Untersuchung der regionalen Verbreitung dieser Hefen in der Weinbauregion Rheinhessen ergab, dass bei 15 % der untersuchten Winzerbetriebe D. bruxellensis in Rotweinproben vorhanden war. Insgesamt konnten bei den Probenuntersuchungen aus 299 Weinen 44 D. bruxellensis-Stämme isoliert werden. Im Rahmen dieser Arbeit wurden darüber hinaus verschiedene Vitalitätsfärbungen hinsichtlich ihrer Anwendbarkeit auf Brettanomyces/Dekkera evaluiert und eine Differenzierung dieser Hefen durch einen physiologischen Mikrotiterplatten-Test (Biolog, USA) überprüft.

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BACKGROUND There is confusion over the definition of the term "viability state(s)" of microorganisms. "Viability staining" or "vital staining techniques" are used to distinguish live from dead bacteria. These stainings, first established on planctonic bacteria, may have serious shortcomings when applied to multispecies biofilms. Results of staining techniques should be compared with appropriate microbiological data. DISCUSSION Many terms describe "vitality states" of microorganisms, however, several of them are misleading. Authors define "viable" as "capable to grow". Accordingly, staining methods are substitutes, since no staining can prove viability.The reliability of a commercial "viability" staining assay (Molecular Probes) is discussed based on the corresponding product information sheet: (I) Staining principle; (II) Concentrations of bacteria; (III) Calculation of live/dead proportions in vitro. Results of the "viability" kit are dependent on the stains' concentration and on their relation to the number of bacteria in the test. Generally this staining system is not suitable for multispecies biofilms, thus incorrect statements have been published by users of this technique.To compare the results of the staining with bacterial parameters appropriate techniques should be selected. The assessment of Colony Forming Units is insufficient, rather the calculation of Plating Efficiency is necessary. Vital fluorescence staining with Fluorescein Diacetate and Ethidium Bromide seems to be the best proven and suitable method in biofilm research.Regarding the mutagenicity of staining components users should be aware that not only Ethidium Bromide might be harmful, but also a variety of other substances of which the toxicity and mutagenicity is not reported. SUMMARY - The nomenclature regarding "viability" and "vitality" should be used carefully.- The manual of the commercial "viability" kit itself points out that the kit is not suitable for natural multispecies biofilm research, as supported by an array of literature.- Results obtained with various stains are influenced by the relationship between bacterial counts and the amount of stain used in the test. Corresponding vitality data are prone to artificial shifting.- As microbiological parameter the Plating Efficiency should be used for comparison.- Ethidium Bromide is mutagenic. Researchers should be aware that alternative staining compounds may also be or even are mutagenic.

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The numerical density of senile plaques (SP) and neurofibrillary tangles (NFT) as revealed by the Glees silver method was compared with SP and NFT revealed by the Gallyas method and with amyloid (A4) deposits in immunostained sections in 6 elderly cases of Alzheimer's disease. The density of NFT was generally greater and A4 lower in tissue from hippocampus compared with the neocortex suggesting that A4 deposition was less important than the degree of paired helical filament (PHF) related damage in the hippocampus. The density of Glees SP was positively correlated Gallyas SP weakly correlated with A4 deposit number. A stepwise multiple regression analysis which included A4 deposit and Gallyas SP density and accounted for 54% of the variation in Glees SP density. Hence, different populations of SP were revealed by the different staining methods. The results suggested that the Glees method may stain a population of SP in a region of cortex where both amyloid deposition and neurofibrillary changes have occurred.

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One-third of botanical remedies from southern Italy are used to treat skin and soft tissue infections (SST's). Methicillin-resistant Staphylococcus aureus (MRSA), a common cause of SSTIs, is responsible for increased morbidity and mortality from infections. Therapeutic options are limited by antibiotic resistance. Many plants possess potent antimicrobial compounds for these disorders. Validation of traditional medical practices is important for the people who rely on medicinal plants. Moreover, identification of novel antibiotics and anti-pathogenic agents for MRSA is important to global healthcare.^ I took an ethnopharmacological approach to understand how Italian medicinal plants used for the treatment of SSTIs affect MRSA growth and virulence. My hypothesis was that plants used in folk remedies for SSTI would exhibit lower cytotoxicity and greater inhibition of bacterial growth, biofilm formation and toxin production in MRSA than plants used for remedies unrelated to the skin or for plants with no ethnomedical application. The field portion of my research was conducted in the Vulture-Alto Bradano area of southern Italy. I collected 104 plant species and created 168 crude extracts. In the lab, I screened samples for activity against MRSA in a battery of bioassays. Growth inhibition was analyzed using broth microtiter assays for determination of the minimum inhibitory concentration. Interference with quorum-sensing (QS) processes, which mediate pathogenicity, was quantified through RP-HPLC of δ-toxin production. Interference with biofilm formation and adherence was assessed using staining methods. The mammalian cytotoxicity of natural products was analyzed using MTT cell proliferation assay techniques.^ Although bacteriostatic activity was limited, extracts from six plants used in Italian folk medicine (Arundo donax, Ballota nigra, Juglans regia, Leopoldia comosa, Marrubium vulgare, and Rubus ulmifolius ) significantly inhibited biofilm formation and adherence. Moreover, plants used to treat SSTI demonstrated significantly greater anti-biofilm activity when compared to plants with no ethnomedical application. QSI activity was evident in 90% of the extracts tested and extracts from four plants ( Ballota nigra, Castanea saliva, Rosmarinus officinalis, and Sambucus ebulus) exhibited a significant dose-dependent response. Some of the plant remedies for SSTI identified in this study can be validated due to anti-MRSA activity.^

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Purpose: The aim of this study was to determine current approaches adopted by optometrists to the recording of corneal staining following fluorescein instillation. Methods: An anonymous ‘record-keeping task’ was sent to all 756 practitioners who are members of the Queensland Division of Optometrists Association Australia. This task comprised a form on which appeared a colour photograph depicting contact lens solution-induced corneal staining. Next to the photograph was an empty box, in which practitioners were asked to record their observations. Practitioners were also asked to indicate the level of severity of the condition at which treatment would be instigated. Results: Completed task forms were returned by 228 optometrists, representing a 30 per cent response rate. Ninety-two per cent of respondents offered a diagnosis. The most commonly used descriptive terms were ‘superficial punctate keratitis’ (36 per cent of respondents) and ‘punctate staining’ (29 per cent). The level of severity and location of corneal staining were noted by 69 and 68 per cent of respondents, respectively. A numerical grade was assigned by 44 per cent of respondents. Only three per cent nominated the grading scale used. The standard deviation of assigned grades was � 0.6. The condition was sketched by 35 per cent of respondents and two per cent stated that they would take a photograph of the eye. Ten per cent noted the eye in which the condition was being observed. Opinions of the level of severity at which treatment for corneal staining should be instigated varied considerably between practitioners, ranging from ‘any sign of corneal staining’ to ‘grade 4 staining’. Conclusion: Although most practitioners made a sensible note of the condition and properly recorded the location of corneal staining, serious deficiencies were evident regarding other aspects of record-keeping. Ongoing programs of professional optometric education should reinforce good practice in relation to clinical record-keeping.

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• Premise of the study: Here we propose a staining protocol using TBO and Ruthenium red in order to reliably identify secondary compounds in the leaves of some species of Myrtaceae. • Methods and results: Leaves of 10 species representing 10 different genera of Myrtaceae were processed and stained using five different combinations of Ruthenium red and TBO. Optimal staining conditions were determined as 1 min of Ruthenium red (0.05% aqueous) and 45 sec of TBO (0.1% aqueous). Secondary compounds clearly identified under this treatment include mucilage in mesophyll, polyphenols in cuticle, lignin in fibers and xylem, tannins and carboxylated polysaccharides in epidermis and pectic substances in primary cell walls. • Conclusions: Potential applications of this protocol include systematic, phytochemical and ecological investigations in Myrtaceae. It might be applicable to other plant families rich in secondary compounds and could be used as preliminary screening method for extraction of these elements.

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Screening new and existing breeding germplasm and cultivars for grain defect tolerance for breeding programs, evaluate new methods and technologies to screen more effectively for the barley grains defects - pre-harvest sprouting, blackpoint, kernel discolouration, and investigate genetic mechanisms involved in controlling barley grain defect tolerance.

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A newly designed fluorescent aluminum(III) complex (L'-Al; 2) of a structurally characterized non-fluorescent rhodamine Schiff base (L) has been isolated in pure form and characterized using spectroscopic and physico-chemical methods with theoretical density functional theory (DFT) support. On addition of Al(III) ions to a solution of L in HEPES buffer (1 mM, pH 7.4; EtOH-water, 1 : 3 v/v) at 25 degrees C, the systematic increase in chelation-enhanced fluorescence (CHEF) enables the detection of Al(III) ions as low as 60 nM with high selectivity, unaffected by the presence of competitive ions. Interestingly, the Al(III) complex (L'-Al; 2) is specifically able to detect fluoride ions by quenching the fluorescence in the presence of large amounts of other anions in the HEPES buffer (1 mM, pH 7.4) at 25 degrees C. On the basis of our experimental and theoretical findings, the addition of Al3+ ions to a solution of L helps to generate a new fluorescence peak at 590 nm, due to the selective binding of Al3+ ions with L in a 1 : 1 ratio with a binding constant (K) of 8.13 x 10(4) M-1. The Schiff base L shows no cytotoxic effect, and it can therefore be employed for determining the intracellular concentration of Al3+ and F-ions by 2 in living cells using fluorescence microscopy.

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Most microbiological methods require culture to allow organisms to recover or to selectively increase, and target organisms are identified by growth on specific agar media. Many cultural methods take several days to complete and even then the results require confirmation. Alternative techniques include the use of chromogenic and fluorogenic substances to identify bacteria as they are growing, selective capture using antibodies after short periods of growth, molecular techniques, and direct staining with or without flow cytometry for enumeration and identification. Future microbiologists may not use culture but depend on the use of specific probes and sophisticated detection systems.

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Reported mast-cell counts in endobronchial biopsies from asthmatic subjects are conflicting, with different methodologies often being used. This study compared three standard methods of counting mast cells in endobronchial biopsies from asthmatic and normal subjects. Endobronchial biopsies were obtained from atopic asthmatic subjects (n=17), atopic nonasthmatic subjects (n=6), and nonatopic nonasthmatic control subjects (n=5). After overnight fixation in Carnoy's fixative, mast cells were stained by the short and long toluidine blue methods and antitryptase immunohistochemistry and were counted by light microscopy. Method comparison was made according to Bland & Altman. The limits of agreement were unacceptable for each of the comparisons, suggesting that the methods are not interchangeable. Coefficients of repeatability were excellent, and not different for the individual techniques. These results suggest that some of the reported differences in mast-cell numbers in endobronchial biopsies in asthma may be due to the staining method used, making direct comparisons between studies invalid. Agreement on a standard method is required for counting mast cells in bronchial biopsies, and we recommend the immunohistochemical method, since fixation is less critical and the resultant tissue sections facilitate clear, accurate, and rapid counts.