No description available.

Consensus opinion suggests that apoptosis occurs when the intracellular redox potential reaches its oxidative range, i.e. when the balance between oxidants and reductants is disturbed. An understanding of the links between redox potential and the induction of apoptosis in cells could improve our understanding of the process and help to predict therapeutic responses. This study investigates the changes in redox potential at distinct stages of apoptosis induced in the human cervical cancer cell line, HeLa. Stages of the apoptotic process were defined by loss of mitochondrial membrane polarisation (ΔΨm), membrane phosphatidyl serine exposure, caspase-3 activation, and nuclear fragmentation. To measure real-time redox potential change in apoptotic cells two independent methods were used: (1) expression of redox-responsive green fluorescent protein (roGFP2) measured by flow cytometry and (2) redox-responsive nanosensors detected by surface enhanced Raman spectroscopy (SERS). roGFP2 measurements showed that HeLa cells demonstrate a shift towards an oxidative redox state during the later stages of apoptosis and this was preceded by loss of ΔΨm. The relationship between these two events was investigated by transient inhibition of mitochondrial permeability transition pore opening using the inhibitor bongkrekic acid (BKA) pre-treatment. At the cell population level, transient exclusion of the mitochondrial contribution delayed two key events of apoptosis in the first two hours measured by nuclear fragmentation and loss of ΔΨm. However, BKA treatment did not affect redox potential, reported by roGFP2, when compared with controls. Therefore, this suggests that mitochondria do not contribute towards the overall redox potential change in apoptosis. To gain insight into the significance of redox change at the earliest stages of apoptosis, single cell studies were performed. SERS, employing simultaneous redox potential and intracellular pH measurements using two synthetic nanosensors AQ-NS and MBA-NS, showed that BKA pre-treatment resulted in increased alkalinity and the cells were consequently protected from induction of apoptosis in the first thirty minutes of the kinase inhibitor staurosporine treatment. Measurements with SERS nanosensors allowed for adjustment for pH, which provides a clearer insight into redox potential dynamics, with consideration of the environment, and accurate quantitative assessment of redox at early stages of apoptosis. Together these data suggest that while roGFP2 is a valid method to use at a population level, SERS is a more sensitive method for measuring the redox potential of the cell at the early stages of apoptosis.

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京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21593号 / 理博第4500号 / 新制||理||1646(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 林 重彦, 教授 谷村 吉隆, 教授 寺嶋 正秀 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Stora Enso is a well-established provider of renewable solution packaging and board materials.Board products for liquid packaging and folding cartons for food are particularly sensitive tothe microbiological contaminants. In the manufacturing process, microbiological growth occursdue to environmental favourable conditions. Most of the microorganisms eventually die in theboard machine. The microflora in the process consists mainly of bacteria from genera Bacillusand Paenibacillus, and these species have a unique characteristic of forming endospores. Thespores are non-vegetative capsules transformed from the dying bacteria, with its purpose ofprotecting the bacterial genome from the unfriendly environment as it passes through in theboard machine. The levels of spores found in the board products are usually low, but suddenpeaks of spores in the board products are unwanted for food and health safety. Bacterial andspore cultivation is a standard method to investigate microbiological activity. The method isinaccessible due to 48-hour incubation time for obtaining test results and does not provide anyoverview in a short time frame of where in the process that might triggered sporulation. In thelong run, it can cause production losses that affect the prospects of the board production.The purpose of this study is to investigate a new analysis method to facilitate identification andquantification of microbiological activity with ATP bioluminescence (AdenosineTriphosphate) measurement and redox potential, and as well investigate the main process sitethat possibly causes the issue. ATP bioluminescence measures the concentration of ATP inrelation to the number of bacterial cells. The study was limited to the broke system due to theclosed system and accumulation of microorganisms. The broke system manages the reuse ofdowngraded new paper board. For the laboratory work, 15 process positions were selected inthe broke system. Pulp were sampled from each process position for each laboratory workday,and measurements of ATP bioluminescence, redox potential, pH, temperature, TOC (totalorganic carbon), retention time, and bacterial and spore cultivation were completed as well. Thecollected data were studied in a multivariate analysis and correlograms were produced for eachprocess position. In addition, a parallel study of a lab scale broke tower simulation wasperformed to further investigate if the broke tower could be the source of the microbiologicalactivity.The obtained results showed low correlations between the process parameters and the totalbacterial and spore concentration. Similar results were obtained for ATP bioluminescence andredox potential, resulted in a low correlation to the total bacterial and spore concentration aswell. The simulation gave additional insight in the function of ATP bioluminescence and redoxpotential.The conclusion is that ATP bioluminescence is an accessible method due to high repeatability,however the reliability is lacking. The analysis is not reliable because of low correlationbetween the total bacterial and spore concentration. Redox potential is both a reliable andaccessible method to identify and quantify the microbiological growth in the system, becauseit signifies the environmental conditions for the bacterial growth. It has been proven in the brokesimulation. Further research is needed to understand the representation in relation to thebacterial growth behind each analysis in order to fully consider the analysing measurementapplicable. Due to low correlations between the variables in each process position, anyassumptions cannot be considered in any specific process position that might be main cause ofraised spore values in board products. / Stora Enso är en väletablerad leverantör av förnybara lösningar för förpackningar ochkartongmaterial. Kartongprodukter för vätskeförpackningar och vikkartong för livsmedel ärsärskilt känslig för mikrobiologisk aktivitet. I tillverkningsprocessen sker mikrobiologisktillväxt på grund av gynnsamma miljöförhållanden. De flesta av de vegetativa cellerna dör såsmåningom i kartongmaskinen, men en stor del av mikrofloran består av bakterier från släktenaBacillus och Paenibacillus. Dessa arter har en unik egenskap att bilda endosporer. Sporerna äricke-vegetativa kapslar som transformerats från de döende bakterierna, med syftet att skyddabakteriegenomet från den ogynnsamma miljön som passeras i genom maskinen. Nivåerna avsporer som finns i kartongprodukterna är låga, men plötsliga förhöjda värden av sporer ikartongprodukterna är oönskade för livsmedels- och hälsosäkerheten. Bakterie- och sporodlingär en standardmetod att undersöka den mikrobiologiska aktiviteten. Metoden är otillgängligvars resultat visas efter 48 timmar inkubation. Metoden ger ingen översikt var i processen somkan ha framkallats sporulering, och detta bildar en diffus överblick var i processen inom korttidsram som kan ha bidragit till sporuleringen. På lång sikt kan det orsakas produktionsförlustersom påverkar kartongproduktionens framtidsutsikter.Syftet med denna studie är att undersöka nya analysmetoder för att underlätta identifiering ochkvantifiering av mikrobiologisk aktivitet med en ATP bioluminescens (Adenosin Trifosfat)mätning och redoxpotential och även undersöka den huvudsakliga processposition som orsakardet huvudsakliga problemet. ATP bioluminescens mäter koncentrationen av ATP i förhållandetill antalet vegetativa celler. Studien begränsades till utskottssystemet på grund av slutet systemoch ansamling av mikroorganismer. För laborationsarbetet valdes 15 processpunkter ut iutskottssystemet. Utskottsmassan togs från varje processpunkt för varje laborationsdag, ochmätningar av ATP bioluminescens, redoxpotential, pH, temperatur, TOC (totalt organiskt kol),retentionstid och bakterie- och sporodling genomfördes också. De insamlade data studerades ien multivariat analys och korrelogram togs fram för varje processpunkt. En parallellundersökning genomfördes med en labbsaklig simulering av utskottstornet för att ytterligareundersöka om tornet är möjligtvis källan till den mikrobiologiska aktiviteten.De erhållna resultaten visade låg korrelation mellan processparametrarna och den totalabakterie- och sporkoncentrationerna i samtliga processpositioner. ATP bioluminescens ochredox potential erhöll låg korrelation mellan den totala bakterie- och sporkoncentrationen, mensimuleringen gav tydligare förståelse i de båda mätningarnas funktion.Slutsatsen är att ATP är en tillgänglig metod eftersom det är repeterbar. Däremot har det visatsatt den är opålitlig, på grund av den låga korrelationen mellan den totala bakteriella ochsporhalten. Redox potential är pålitlig att använda, vilket har visats i simuleringen. Denförklarar de miljömässiga förhållandena i systemet och på så sätt stärks förståelsen om denbakteriella tillväxten. Vidare forskning behövs för att förstå betydelsen i samband med denbakteriella tillväxten bakom varje mätning för att analysmetoden ska vara applicerbar. På grundav låga korrelationer mellan variablerna i varje processposition kan några antaganden intebeaktas i någon specifik processposition som kan vara huvudorsaken till förhöjda sporvärden ikartongprodukter.

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Master of Science / Food Science Institute -- Animal Science & Industry / Karen A. Schmidt / Yogurt starter and probiotic bacteria have been reported to confer health benefits to the consumer; however, to confer these health benefits yogurt and probiotic bacteria should be live and present at the recommended concentration of 6 to 8 log cfu g-1. Cegemett® Fresh (Cognis Nutrition & Health, Monheim, Germany) is a plant extract that possesses antioxidant properties. This research was divided into two experiments. The objective of experiment-I was to investigate the effect of plant extract supplementation on the redox potential (Eh) and the viability of starter cultures (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) in nonfat yogurt. Five yogurt samples [non-supplemented, supplemented with 0.5 or 1.0% (w/v) plant extract, or supplemented with 0.014 or 0.028% (w/w) L-cysteine.HCl] were prepared, stored at 5ºC for 50 days and analyzed weekly. L. bulgaricus counts in supplemented yogurts were > 6 log cfu mL-1 for additional 7 to 21 days compared with non-supplemented yogurt; however, S. thermophilus counts in all yogurts were > 6 log cfu mL-1 throughout the storage. Overall, Eh of plant extract supplemented yogurts were similar to non-supplemented yogurt during storage; therefore the improvement in L. bulgaricus viability cannot be attributed to the Eh alone. The objective of experiment-II was to investigate the effect of plant extract supplementation on the buffering ability of the yogurt mix, and on the viability of starter and probiotic (Bifidobacterium animalis ssp. animalis and Lactobacillus acidophilus) cultures in nonfat yogurt stored at 5ºC for 50 days. Nine yogurt samples were prepared with 0.5% (w/v) plant extract, 0.25% (w/v) sodium acetate or no supplement, fermented with starter cultures and B. animalis, L. acidophilus or both probiotics, and analyzed weekly. The plant extract and sodium acetate supplemented yogurt mixes had greater buffering capacities compared with non-supplemented yogurt mix. L. bulgaricus and L. acidophilus counts in supplemented yogurts were > 6 log cfu mL-1 for additional 7 to 35 days compared with non-supplemented yogurts. S. thermophilus and B. animalis counts were not affected by supplementation. These results suggested that greater buffering capacity could improve the viability of L. bulgaricus and L. acidophilus in yogurt during storage.

Arsenic (As) appears in the environment as various As species, which may vary in plant uptake and toxicity. Moreover, As exposure may vary between habitat due to availability and speciation, both of which are influenced by redox potential. To decrease As uptake, addition of silicate may be a tool. The aim of the study was to investigate how the external factors As availability, plant habitats, silicon and oxygen level, influenced the accumulation and speciation of As in plants for food and phytoremediation in a temperate region. The external factors were chosen due to their previously showed influence on As in plants. The risks with dietary As was investigated by plant As accumulation and speciation in carrot, lettuce and spinach grown in alum shale and glassworks soils, and by the influence of silicon on As accumulation in lettuce in hydroponics. Suitable plants for As phytoremediation was investigated by analysing plants from various habitats, and by the O2 influence on phytofiltration. The results showed that vegetables accumulated more As in soils with higher As extractability, and the As extractability in the rhizosphere was higher than in bulk soil. Also, the As concentration in lettuce was higher in hydroponics than in soil, but silicon reduced the accumulation of As in lettuce in hydroponics. Also, the more toxic inorganic As were the main As species detected in vegetables, compared with the less toxic organic As. For phytoremediation, the results showed a low As accumulation in emergent and terrestrial plants. Submerged plants had had a higher shoot As concentration. In general, the habitat had a major influence on the As accumulation in plants. The results also showed that the As accumulation properties in Elodea canadensis was reduced at higher O2. In conclusion, consumption of vegetables cultivated in As polluted soils can result in an elevated intake of inorganic As, and E. canadensis is a promising candidate for As phytofiltration in a temperate region. / <p>At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Manuscript; Paper 4: Manuscript; Paper 5: Manuscript.</p>

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Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-07-26T14:29:37Z No. of bitstreams: 1 2011 - Erica Souto Abreu Lima.pdf: 2820587 bytes, checksum: d25ffc37d1a7468d5bf9a15ae5e020b7 (MD5) / Made available in DSpace on 2016-07-26T14:29:37Z (GMT). No. of bitstreams: 1 2011 - Erica Souto Abreu Lima.pdf: 2820587 bytes, checksum: d25ffc37d1a7468d5bf9a15ae5e020b7 (MD5) Previous issue date: 2011-02-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior-CAPES / LIMA, Erica Souto Abreu. Dynamic of barium in soils treated with barite. 2011. 44p. Dissertation (Master Science in Agronomy, Soil Science) Instituto de Agronomia, Departamento de Solos, Universidade Federal Rural do Rio de Janeiro, Serop?dica, RJ, 2011. Barite is the natural mineral form of barium sulfate (BaSO4), which is used in drilling fluids for oil wells exploration. Although barium sulfate is poorly soluble, and therefore, not very bioavailable to plants and with low mobility, it is not know the magnitude of changes in its dynamics under reducing soil conditions. Thus, the main objective of the study was to evaluate if under extreme reduction conditions the solubilization and release of barium in the soil would occur, increasing risk of contamination to plants and groundwater. Two experiments were conducted in parallel, one in leaching columns and the other in pots, where rice was cultivated as a test plant. In both trials soil samples from an Udox soil were used. The installation of experiments followed a completely randomized design in factorial scheme (4 x 2) with four replications, i.e., composed of control and three levels of barium (100, 300, and 3000 mg kg-1), two moisture levels (at 70% of field capacity and saturated with the maintenance of a 5 cm layer of water), totaling 32 experimental units. The redox potential (Eh), and pH values to reach the Eh of -200 mV were monitored. After reaching these values a rainfall of 200 mm day-1 was simulated in the columns, and volumes of 200 mL were collected. The extract was divided into volumes of 200 mL, corresponding to 1/8 of the soil pore volume, and they were analyzed for levels of barium and other toxic metals. The rice (Oryza sativa L.) plants in the vases remained throughout the vegetative cycle up to about 4 months, when they were harvested and analyzed. The geochemical fractionation was also performed for the elements barium, manganese and iron, by the BCR method. The results showed that the addition of doses of barite in soil, and the condition of extreme reduction led to the increase of barium, iron and manganese in the highest labile fractions. Thereby promoting higher levels of barium in the leachate extract. Under these conditions, the plants showed growth and development reduction. However, the barium may not be the main cause of this reduction, which may be linked to iron toxicity and lower absorption of zinc, phosphorus and calcium. / A baritina ? a forma mineral natural de sulfato de b?rio (BaSO4), que ? amplamente utilizada nos flu?dos de po?os de prospec??o de petr?leo. Apesar do sulfato de b?rio ser pouco sol?vel, e consequentemente, pouco biodispon?vel para as plantas e de baixa mobilidade, n?o se conhece a magnitude das altera??es na sua din?mica em condi??es redutoras do solo. Diante disso, o objetivo principal do estudo foi avaliar se em condi??es de extrema redu??o ocorre o aumento da solubiliza??o e como conseq??ncia libera??o do b?rio no solo, potencializando o risco de contamina??o para as plantas e ?guas subterr?neas. Foram realizados dois experimentos em paralelo, sendo um em colunas de lixivia??o e o outro em vasos, onde foi cultivado arroz como planta teste. Em ambos os ensaios foram utilizadas amostras de terra coletadas de Latossolo Vermelho Amarelo. A instala??o dos experimentos seguiu o delineamento experimental inteiramente casualizado, em esquema fatorial (4 x 2) com 4 repeti??es, ou seja, composto por testemunha e tr?s doses de b?rio (100, 300 e 3000 mg kg-1), dois teores de umidade (70% CC e saturado com presen?a de l?mina de 5 cm), totalizando 32 unidades experimentais. Foram monitorados o potencial redox (Eh) e o pH, at? atingirem valores de Eh de -200 mV. Ap?s atingirem esses valores foi simulada uma precipita??o pluviom?trica de 200 mm dia-1 nas colunas, onde foram coletados volumes de 200 mL. O extrato foi dividido em volumes de 200 mL, que correspondem a 1/8 do volume de poro da coluna de solo, para em seguida serem analisados quanto aos teores de b?rio e outros metais considerados t?xicos. As plantas de arroz (Oryza sativa L.) foram cultivadas nos potes por todo o ciclo vegetativo (aproximadamente 4 meses) at? serem colhidas e analisadas. Tamb?m foi realizado o fracionamento geoqu?mico para os elementos b?rio, mangan?s e ferro pelo m?todo BCR. Os resultados obtidos evidenciaram que a adi??o das doses de baritina no solo e a condi??o de extrema redu??o, propiciaram o aumento de b?rio, ferro e mangan?s nas fra??es de maior labilidade. Promovendo, assim, maiores teores de b?rio no extrato lixiviado. Nessas condi??es, as plantas apresentaram redu??o no seu crescimento e desenvolvimento. Por?m o b?rio pode n?o ser o principal causador dessa redu??o, podendo esta estar ligada a toxicidade do ferro e a uma menor absor??o de zinco, f?sforo e c?lcio.