Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-05T12:37:57Z No. of bitstreams: 1 2011 - Simone de Souza Fernandes.pdf: 745580 bytes, checksum: 7836d760ce3ea36d3e5602714715cd42 (MD5) / Made available in DSpace on 2016-10-05T12:37:57Z (GMT). No. of bitstreams: 1 2011 - Simone de Souza Fernandes.pdf: 745580 bytes, checksum: 7836d760ce3ea36d3e5602714715cd42 (MD5) Previous issue date: 2011-05-27 / Yogurt is a fermented milk resulting from a mutual interaction between the lactic acid bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. For yoghurt quality assurance, the cell numbers of each microorganism, should not be less than 1x107per gram, therefore a relative ratio lactobacilli and streptococci should be 1:1, although a 1:2 ratio is also accepted. During storage of yoghurt exposed for sale, post-acidification may occur, changing the ratio of the two microorganisms. The objectives of this research were to evaluate yoghurts of four different manufacturers named A, B, C and D, in relation to the number and balance between streptococii and lactobacilli during the storage and its relation with acidity and pH. In this way, yoghurts with up to 20 days of manufacturing (band I) and more than 20 days (band II) were evaluated. Better recovery of L. delbruckii subsp. bulgaricus and S. thermophilus was observed with LB and M17 media respectively, which were used to determine the relative ratio of the two microorganisms. An imbalance in the lactobacilli numbers which were lower than that of streptococci was verified and considered inadequate, in two out of four commercial brands. In yoghurts from the manufacturer A, there was a significant reduction in the number of lactobacilli from band I to band II leading to an increase in the relative ratio of streptococii to lactobacilli. There was no significant difference in the counts of streptococci or bacilli from one band to another with the other three brands of yoghurts. The acidity of yoghurts from manufacturer D revealed significantly higher (P< 0.05) than the others, although it did not result in an increased pH reduction. All samples attended the legislation in relation to total lactic acid bacteria counts, acidity, pH and mould and yeast count / Iogurte ? um leite fermentado resultante de uma intera??o microbiana mutualista entre as bact?rias l?cticas Streptococcus thermophilus e Lactobacillus delbrueckii subsp. bulgaricus. Para que a qualidade do iogurte seja garantida o n?mero de c?lulas destes dois microrganismos individualmente, n?o deve ser inferior a 1x107 por grama, portanto uma propor??o relativa de lactobacilos e estreptococos de 1:1 sendo a propor??o 1:2 tamb?m aceita. Durante o armazenamento dos iogurtes expostos para venda podem ocorrer p?s-acidifica??o e modifica??o na propor??o dos dois microrganismos. Os objetivos desta pesquisa foram avaliar iogurtes de quatro diferentes fabricantes as quais foram denominados A, B, C, D quanto ao n?mero e equil?brio entre as duas bact?rias l?cticas durante o armazenamento, e ao mesmo tempo determinar as caracter?sticas f?sico-quimicas (pH e acidez) e contagem de bolores e leveduras. Para tanto, adotou-se duas faixas de avalia??o, faixa I (at? 20 dias de fabrica??o) e faixa II (ap?s 20 dias). Foi observada melhor recupera??o L. delbruckii subsp. bulgaricus e S. thermophilus, respectivamente com os meios LB e M17 que foram usados para determina??o da propor??o relativa dos dois microrganismos. Foi verificado um desequil?brio no n?mero de lactobacilos que foi inferior ao de cocos e, considerado inadequado, em duas das quatro marcas comerciais. Nos iogurtes da marca A houve redu??o significativa no n?mero de lactobacilos da faixa I para faixa II levando a um aumento na propor??o de cocos relativa ao de bacilos. Nos iogurtes dos tr?s outros fabricantes n?o houve diferen?a significativa nas contagens de cocos ou de lactobacilos de uma faixa para outra. Tamb?m n?o foi observada diferen?a significativa de acidez e pH relacionados ao tempo de prazo comercial nas faixas I e II nas quatro marcas de iogurte analisadas. A acidez dos iogurtes do fabricante D foi significativamente mais elevada (P<0,05) que a dos demais, embora n?o tenha resultado em maior redu??o de pH nestes produtos. Todas as amostras analisadas estavam em conformidade com a legisla??o vigente no que se refere ao m?nimo exigido de bact?rias l?ticas totais que ? de 1x107 UFC/mL. Tamb?m estavam em conformidade com rela??o ? acidez, pH e contagem de bolores e leveduras. Palavras-chave: leite

L’objectif de la thèse s’inscrit dans le cadre de contribuer à l’estimation des paramètres du système des carbonates en Mer Méditerranée, en particulier la pression partielle du CO2 dans l’eau (pCO2sw), l’alcalinité totale (AT), le carbone inorganique total (CT) et le pH. En premier lieu, on a calculé à partir des données des campagnes Boum en 2008 et MedSeA en 2013 les coefficients de mélange des masses d’eau dans les bassins Ouest et Est. L’analyse de ces coefficients nous a permis d’étudier l’évolution des masses d’eau en Mer Méditerranée entre les années 2008 et 2013.En deuxième lieu, on a présenté à partir des données de la mission MedSeA en mai 2013, les résultats des mesures récentes de pCO2sw sur une section longitudinale assez étendue allant du détroit de Gibraltar jusqu’au sous-bassin Levantin. Les résultats ont indiqué que les bassins Ouest et Est sont gouvernés par deux régimes différents de pCO2sw. Ces deux régimes ont été influencés par les propriétés physico-chimiques assez distinctes des deux bassins. A partir des mesures directes de pCO2sw on a calculé les flux journaliers de CO2 à travers l’interface air-mer en mai 2013 et cela pour le trajet couvert par la mission MedSeA. Pour aboutir à une analyse plus globale on s’est référé dans une étude ultérieure, aux données des campagnes Thresholds et MedSeA. On a établit ainsi deux équations pour estimer en mai 2007 et 2013, la pCO2sw à partir des données satellites de température de surface, Chlorophylle_a et l’index de la couleur de la matière organique dissoute. Puis, on a calculé et cartographié les flux air-mer de CO2 en mai 2013 à l’échelle de toute la Mer Méditerranée et pour une résolution spatiale de 4 km.Ensuite, on a établi à partir des données de la mission MedSeA, des régressions linéaires pour estimer l’AT et le CT à partir de la salinité, et cela pour chaque sous-bassin de la Mer Méditerranée et pour plusieurs intervalles de profondeur. Ultérieurement, on s’est concentré aux données physico-chimiques dans les eaux de surface, compilées de plusieurs campagnes océanographiques entre 1998 et 2013. Les équations établies pour estimer l’AT et le CT dans les eaux de surface, ont indiqué que le meilleur polynôme inclue la salinité et la température. Ces polynômes ont été appliqués sur les cartes climatologiques de température et de salinité du World Ocean Atlas, pour cartographier les variabilités spatiales et saisonnières de l’AT et du CT sur une moyenne de 7 ans. En outre, à partir des données de la mission MedSeA, on a estimé les concentrations en carbone anthropique (CANT) et la variation de l’acidification (∆pH) en Mer Méditerranée. Les résultats ont indiqué que la Mer Méditerranée est fortement contaminée par le CANT avec des concentrations bien plus élevées que celles enregistrées dans l’océan Pacifique ou Indien. Le calcul du ∆pH a indiqué que la Mer Méditerranée est déjà acidifiée de la surface jusqu’en profondeur. Enfin, on a présenté un modèle pour prédire le ∆pH en fonction de concentrations théoriques de CANT. On a montré que le seuil en CANT pour lequel l’acidification va fortement s’intensifier en Mer Méditerranée est déjà atteint. Aussi, les eaux profondes des bassins Occidental et Oriental, deviendront très probablement sous saturées par rapport à la calcite et à l’aragonite d’ici la fin du siècle prochain. / The objective of the thesis is to contribute to the estimation of the carbonate system parameters in the Mediterranean Sea, in particular the partial pressure of CO2 in water (pCO2sw), total alkalinity (AT), total inorganic carbon (CT) and pH.The study was initiated by an adequate calculation of the water masses mixing coefficients in the Western and Eastern basins, using data from the Boum and MedSeA cruises in 2008 and 2013, respectively. The analysis of the mixing coefficients, allowed us to study the evolution of water masses in the Mediterranean Sea between the years 2008 and 2013.Subsequently, using data from the 2013 MedSeA cruise, we presented the results of recent measurements of pCO2sw on a wide longitudinal section from the Strait of Gibraltar to the Levantine sub-basin. The results indicated that the Western and Eastern basins were characterized by two different pCO2sw regimes. These regimes were mainly affected by the distinctive physico-chemical properties of each basin. From the direct measurements of pCO2sw we calculated along the track of the MedSeA cruise, the daily CO2 fluxes across the air-sea interface in May 2013. To achieve a more comprehensive analysis, we referred in a consecutive study to the data of the Thresholds and MedSeA cruises. From these data, we provided two equations to estimate in May 2007 and 2013; pCO2sw from satellite data of sea surface temperature, Chlorophyll_a and the chromophoric dissolved organic matter index. Furthermore, we calculated and mapped the air-sea CO2 fluxes in May 2013 across the whole Mediterranean Sea, with a spatial resolution of 4 km.Successively, we established from the MedSeA cruise data, linear regressions to estimate AT and CT from salinity, in each sub-basin of the Mediterranean Sea and for several depths. Later on, we focused on the physico-chemical data in surface waters, compiled from several oceanographic cruises between 1998 and 2013. The equations developed to estimate the AT and CT in surface waters, indicated that it is best to include in these polynomials both salinity and temperature. These polynomials were applied to the climatological fields of salinity and temperature of the World Ocean Atlas, in order to map the spatial and seasonal variability of AT and CT on a 7 years average.Moreover, we estimated from the MedSeA cruise data, the concentrations of anthropogenic carbon (CANT) and the variation of acidification (ΔpH) in the Mediterranean Sea. The results indicated that the Mediterranean Sea is heavily contaminated by CANT, with higher concentrations than those recorded in the Pacific or Indian Ocean. Also, the calculated ΔpH indicated that the Mediterranean Sea is already acidified from the surface to the deep waters. Finally, we presented a model to predict the ΔpH according to theoretical concentrations of CANT. Consequently, we showed that we already reached the tipping point of CANT, for which the acidification will strongly intensify in the Mediterranean Sea. Moreover, the deep waters of the Western and Eastern basins are very likely to become under saturated in calcite and aragonite by the end of the next century.

Climate change is ecologically and socially complex, deemed the most important issue of our generation. Through this dissertation I have approached climate change research through an interdisciplinary perspective, investigating how this phenomenon will affect marine ecological systems, how we can better develop experimental systems to answer ecological questions, and how we can effectively educate about this issue. In Chapter 2, I provided accessible alternatives for researching the effects of climate change (elevated temperatures and pCO2) on marine ecosystems. I designed, built, and troubleshooted two accurate and inexpensive climate-controlled experimental systems capable of maintaining target conditions: a temperature-controlled system and an ocean acidification system. The temperature-controlled system was designed to manipulate experimental tank temperatures indirectly by controlling the temperature in a surrounding water bath, which buffered fluctuations and resulted in a high level of control. The ocean acidification experimental system was designed to elevate normally fluctuating pCO2 levels by a constant factor, which allowed pCO2 to fluctuate as expected in natural environments and made it more ecologically relevant than active pCO2-controlled systems. In Chapter 3, I experimentally tested the morphological responses of southern ribbed mussels Geukensia granosissima to two simultaneous stressors (elevated temperatures and the presence of water-borne predation cues from blue crab Callinectes sapidus) and if any effects of these treatments led to differences in handling times by predatory crabs. Bivalves may become more susceptible to predation as increased temperatures decrease the protection afforded by their shells, but few studies have tested the effects of elevated temperatures on inducible defenses in bivalves. Results showed that chronic heat stress can have detrimental morphological effects on intertidal mussels. Mussels reared in elevated temperatures manifested elongated shell shapes, exhibited a disruption of the predator effect on inducible defenses, and experienced decreased predator handling times. The observed responses to elevated temperatures could make southern ribbed mussels more vulnerable to predation. In Chapter 4, I experimentally tested the morphological responses of southern ribbed mussels to elevated pCO2 levels and the presence of water-borne predation cues from blue crabs, and if these effects led to differences in handling times by predatory crabs. Elevated pCO2 can have negative effects on bivalves’ morphology and physiology, but the consequences of these effects on predator-prey interactions are still unclear. I found that adult southern ribbed mussels’ inducible defenses were not affected by a medium-term exposure to elevated pCO2. Mussels grew more in shell length and width as a response to predation cues, independent of pCO2 conditions. However, and unexpectedly, mussels reared under elevated pCO2 exhibited greater growth in shell width independent of predator treatment, driving mussels reared in the presence of a predator under elevated pCO2 conditions to develop rounder shapes. On average, these effects on mussel morphometrics did not affect crab handling times, but mussels reared in the presence of a predator under elevated pCO2 conditions had highly variable handling times. It is important to consider the complexity of animal physiology, morphology, and interspecies relationships when making deductions on predator-prey relationships in a changing ocean. In Chapter 5, I analyzed the effectiveness of using an interdisciplinary approach to climate change education. Literature suggests that an interdisciplinary instructional framework in an outdoor setting, using tools from the experiential, active, and inquiry- and place-based learning approaches, as well as the socioscientific issues pedagogical framework, would be an excellent approach for climate change education. I found that students: increased their content knowledge on climate change causes and consequences, exhibited a deeper understanding of climate change through the words they used to describe it, and corrected common climate change misconceptions. This work can serve as an example for the development of effective climate change programs that uses already available instructional materials with intentional interdisciplinary goals. Our search to understand how marine ecosystems will cope with a changing climate has emphasized emerging issues in the way we gather data, the questions we seek to answer through research, and how we translate science of social importance to the public. Through this dissertation I strove to seek the answers to some of these questions and provide feasible solutions to some of the problems in climate change research and education through an interdisciplinary approach. As science continues to move towards answering questions of concern for both science and society, science research is moving towards more interdisciplinary approaches. This dissertation is an example of how this can be an efficient and comprehensive approach.

Increased groundwater usage, rainfall decline and activities such as mining have resulted in the acidification of certain wetlands in the south-west of Western Australia. This study investigated the influence of pH, the factor most commonly associated with acidification, on the invertebrate and diatom community structure of 20 wetlands in the south-west region of Western Australia. Few studies in Western Australia have investigated both biotic groups, particularly in relation to pH. Consequently, this study examined the comparative sensitivity of the two biotic groups to pH in order to identify the most effective biotic tool for assessing the ecological impacts of pH decrease. The wetlands included in this study displayed a wide range of pH from acidic (pH < 6.5) to alkaline (pH > 7.5). Other environmental parameters were also variable. Separation of the wetlands into three pH groups; Group 1 – acidic, Group 2 – circumneutral and Group 3 – alkaline, demonstrated that the acidic Group 1 wetlands generally had higher electrical conductivity than the remaining groups. This was probably due to the association of many Group 1 sites with mining and acid sulphate soils. Seasonal trends in environmental variables across the three pH groups were mostly unclear although some trends were evident within the individual pH groups. The study showed that invertebrate community structure differed in response to pH. However, the results also demonstrated that invertebrate distribution patterns were influenced by other factors. / Potential indicator species identified from the study included Macrothrix indistincta and Tanytarsus fuscithorax/semibarbitarsus which were abundant in acidic waters and Alona quadrangularis which was common in circumneutral sites. Taxa such as Calamoecia tasmanica subattenuata were common over a wider range of pH (acidic to circumneutral) but may still have potential to act as indicators of pH decline. Diatom community structure was also shown to be influenced by pH, with the variable identified as a major determinant of diatom distribution patterns. Nitzschia paleaeformis and Navicula aff. cari were generally recorded from acidic wetlands and are potentially useful as indicators of low pH conditions. Brachysira brebissonii and Frustulia magaliesmontana were also identified as species with the potential to indicate pH decline. In contrast, taxa including Gomphonema parvulum, Staurosira construens var. venter and Nitzschia palea were generally associated with moderate to high pH levels. A comparative study of the two biotic groups using multivariate analyses revealed that diatoms were more sensitive to pH than invertebrates. Further investigation with a larger number of environmental variables would be necessary to ascertain the other factors primarily influencing invertebrate community structure. Nonetheless, the findings imply that diatoms and invertebrates differ in their responsiveness to various environmental factors and may provide complementary information on the integrity of a system. Multivariate analyses on an expanded data-set of 40 sites found that pH accounted for the greatest amount of variation in the data and was conducive to the development of a diatom-based pH inference model. / The strongest model was produced using weighted averaging (WA) with classical deshrinking. While the model displayed a high correlation coefficient, the prediction error was also relatively high, probably as a result of the comparatively small and heterogeneous data-set. Incorporation of the data into a larger training set would be likely to improve the predictive ability. Applications for the model include pH reconstructions or use in monitoring programs. The current study has shown that pH is an important variable influencing both invertebrate and diatom community structure in wetlands in the south-west of Western Australia. However, the greater sensitivity of diatoms to pH suggests that they would be the most effective tool for the biological monitoring of pH in wetlands threatened or impacted by acidification. An integrated monitoring program including both diatoms and invertebrates may provide additional information on the impacts of pH decline and the overall integrity of the systems and should be investigated further.

Outgrowth of spoilage yeasts and moulds and post-processing acidification can limit the shelf-life of some fermented dairy products including fresh lactic curd cheeses. The possibility of using high pressure processing (HPP) for controlling these problems was investigated in a commercially manufactured fresh lactic curd cheese (pH 4.3-4.4) and fermented milk models (pH 4.3-6.5). The effects of HPP at 300 and 600 MPa on inactivation of glycolytic enzymes of lactic acid bacteria were also evaluated. Fresh cheeses made from pasteurised bovine milk using a commercial Lactococcus starter preparation were treated with high pressures ranging from 200 to 600 MPa (less than or equal to 22°C, 5 min) under vacuum packaging conditions and subsequently stored at 4°C for 8 weeks. Treatment at greater than or equal to 300 MPa substantially reduced the viable count of Lactococcus and effectively prevented the outgrowth of yeasts and moulds for 6 to 8 weeks without adversely affecting the sensory and textural attributes of the product. However, it had no significant effects (p less than 0.01) on variation of titratable acidity during storage. Fermented milk models were prepared by individually growing Lactococcus lactis subsp. lactis C10, Lactococcus lactis subsp. cremoris BK5, Streptococcus thermophilus TS1, Lactobacillus acidophilus 2400 and Lactobacillus delbrueckii subsp. bulgaricus 2517 in UHT skim milk and diluting the resulting fermented milk with UHT skim milk up to pH 6.5. Pressure treatment of the milk models at pH 5.2 resulted in substantial inhibition of post-processing acidification during storage and markedly reduced the viable count of Lactococcus at both 300 and 600 MPa and other bacteria only at 600 MPa. Treatment of the milk model at 600 MPa decreased the viable counts of Candida zeylanoides and Candida lipolytica (wildtype spoilage yeasts of lactic curd cheese, added as challenge cultures) from 105 CFU mL-1 to below the detection limit (log 0 CFU mL-1) at all pH levels tested (pH 4.3-6.5) and effectively controlled their outgrowth for 8 weeks. Treatment of milk model at 300 MPa had a similar effect only on C. zeylanoides. The viable count of C. lipolytica was reduced by 2.6, 2.4 and 2.3 logs by treatment at 300 MPa at pH levels of 4.3, 5.2 and 6.5, respectively, which subsequently recovered by 2.9, 2.8 and 3.2 logs within 3 weeks. Glycolytic enzymes of various starter bacteria showed different responses to pressure treatment. The lactate dehydrogenase in L. lactis subsp. lactis and Lb. acidophilus was quite resistant to pressures up to 600 MPa, but it was almost completely inactivated in S. thermophilus at pressure levels as low as 300 MPa. The â-galactosidase in Lb. acidophilus was more pressure stable than â-galactosidase in S. thermophilus and Phospho-â-galactosidase in L. lactis subsp. lactis. The findings of this study suggests HPP at 300-600 MPa as an effective method for controlling the outgrowth of some spoilage yeasts and moulds in fresh lactic curd cheeses. The results obtained with selected lactic acid bacteria in fermented milk models can be used to assist in establishing HPP operating parameters for development of new generation cultured dairy products, of reduced acidity and extended shelf-life.

Les voies d'endocytose chez l'amibe Dictyostelium discoideum ont été explorées en étudiant l'acidification des compartiments endocytaires et en caractérisant l'action de la caféine et de la cycloheximide, deux inhibiteurs qui ne modifient pas le métabolisme énergétique de la cellule.<br />Le dextran marqué par l'isothiocyanate de fluorescéine (FITC dextran) a été employé comme sonde de phase fluide. Dictyostelium montre une internalisation de fluide plus active dans un milieu nutritif que dans un milieu non nutritif. Dans les deux cas, une cinétique biphasique est observée avec une première phase linéaire en fonction du temps, suivie d'un plateau qui correspond à l'équilibre dynamique entre l'entrée et la sortie de fluide. Les cinétiques sont modélisables sur la base d'un compartiment endocytaire unique. L'activité pinocytaire diminue avec la température avec une énergie d'activation de 27 kcal/mol.<br />Le FITC dextran a été utilisé comme sonde de pH. Au plateau de pinocytose, le compartiment endosomal est à une valeur moyenne de pH 5,8 (+/- 0,2) qui est indépendante du pH extracellulaire. Les bases faibles et d'autres agents comme la monensine ou le carbonyl cyanide m-chloro phenylhydrazone, diminuent l'acidité du compartiment endosomal. La détermination du pH endosomal pendant les phases initiales (t<15 min) met en évidence un compartiment plus acide que le compartiment endosomal majeur. Le pH endosomal reste constant pendant l'engagement de la différenciation induite par une carence nutritionnelle. <br />La caféine inhibe de façon immédiate toutes les activités endocytaires chez l'amibe Dictyostelium : la pinocytose de phase fluide, la phagocytose et la sécrétion des enzymes lysosomales. La caféine est aussi un inhibiteur de la croissance axénique dans la même gamme de concentrations que celles qui inhibent l'endocytose. D'autres méthylxanthines, comme la théobromine, la théophylline ou la paraxanthine sont sans effet sur l'endocytose ou la croissance de Dictyostelium. L'hypothèse pour expliquer l'effet inhibiteur de la caféine est une perturbation de l'homéostasie du Ca2+ intracellulaire.<br />La cycloheximide est un inhibiteur de la synthèse protéique chez les eucaryotes. Après une phase de latence d'environ 10 minutes, la cycloheximide bloque toutes les activités endocytaires chez l'amibe Dictyostelium. D'autres inhibiteurs de la synthèse protéique des cellules eucaryotes qui possèdent des modes d'action et des structures différents, tels que l'anisomycine, l'émétine, la pactamycine et la puromycine inhibent aussi l'endocytose. L'hypothèse envisagée pour rendre compte de l'inhibition de l'endocytose par les inhibiteurs de la synthèse protéique fait intervenir des mécanismes de réponse au stress.

<p>Since the start of the industrialisation, the deposition of nitrogen and sulphur and the atmospheric concentrations of greenhouse gases have increased. The main objectives of this study were to find how these changes in climate and deposition can change the vegetation of mire ecosystems and the growth of <i>Sphagnum</i>species. Two main approaches were applied: re-investigated of two mires previously investigated 40-50 years ago and experiment manipulations. </p><p>The plant species diversity had decreased on one of the two re-investigated mires (Skattlösbergs Stormosse; central Sweden), but the total number of species was unchanged on the other (Åkhultmyren; southern Sweden). On Skattlösbergs Stormosse, an acidification was found in the high pH areas, coinciding with reduction in rich fen species. At Åkhultmyren, there was a similar reduction in pH, but the changes in the plant composition also indicated increased nutrient levels and a drier mire surface. Therwere large changes in species composition on Åkhultmyren. For instance <i>Scheuchzeria palustris</i> had disappeared from the investigated area. Further, the cover of Scots pine (<i>Pinusylvestris</i>) had increased, which can be explained by a changed ground-water table regime. Monitoring of pines growing on a bog over a ten-year period showed that pines growing higher above the ground-war table had higher survival than lower-growing pines.</p><p>Experimental addition of nitrogen during 3-4 years reduced <i>Sphagnum </i>growth in bogs and poor fens repressenting a wide range of ambient nitrogen deposition. A changed interspecific competitive relation was found between <i>S. lindberg</i>and <i>S. balticum</i> when increasing nitrogen influx, but the competitive relations between two hummock-growing species pairs did not change in a three-year nitrogen fertilization study. Sulphur additiodid not affect the production or length increment in <i>S. balticum</i>. An increased temperature reduced <i>Sphagnum </i>growth, but there were no indications of altered competitive relationshipbetween hummock and hollow inhabiting <i>Sphagnum </i>species in a four-year experiment.</p>

This study characterizes the mass transport of ions in two streams in the Great Smoky Mountains National Park, comparing transport between stormflow and baseflow periods. By comparing ion mass transport between these two hydrological conditions, the importance of soil and the governing biogeochemical processes will be underscored. Two water quality monitoring study sites were located on the Middle Prong of the Little Pigeon River and Ramsey Prong within the same basin. These remote sites were equipped with YSI 6920 multi-parameter sonde to record continuous 15-min data of pH, depth, conductivity, turbidity, and temperature. Additionally, ISCO 6712 composite samplers were used to collect stream samples during storm events. Baseflow was collected by grab samples prior to storm events, and stormflow collected by ISCO samplers. Throughfall samples were collected after storm events. All samples were analyzed for pH, ANC, and conductivity using an autotitrator. Inductively coupled plasma spectrometry and ion chromatography were used to determine major cations, trace metals, and anions (Ca2+, Na+, K+, Mg2+, Aln+, Cu, Fe, Mn, Si, Zn, SO42-, NO3-, Cl-, NH4+). Stage-discharge relationships were developed at each site utilizing a combination of field measurements and modeling. Velocity and area field measurements were taken to calculate discharges for mid- to low-flow stages while mid- to upper-flow stages were modeled using RIVER2D and verified with field measurements. Stage-discharge curves and sample ion concentrations were used to compute ion mass transport for a two year period in 2006 through 2008. Differences in mass transport of ions between baseflow and stormflow periods found that greater mass transport of ions, except protons, occurred during baseflow periods. These results indicate that on an annual basis ions are stored from input throughfall sources and released gradually through groundwater flow over time more than rapid interflow transport during storm events. This information illustrates the importance of soils and groundwater storage in the regulation of ion transport and streamwater quality in the Great Smoky Mountains National Park.

Since the start of the industrialisation, the deposition of nitrogen and sulphur and the atmospheric concentrations of greenhouse gases have increased. The main objectives of this study were to find how these changes in climate and deposition can change the vegetation of mire ecosystems and the growth of Sphagnumspecies. Two main approaches were applied: re-investigated of two mires previously investigated 40-50 years ago and experiment manipulations. The plant species diversity had decreased on one of the two re-investigated mires (Skattlösbergs Stormosse; central Sweden), but the total number of species was unchanged on the other (Åkhultmyren; southern Sweden). On Skattlösbergs Stormosse, an acidification was found in the high pH areas, coinciding with reduction in rich fen species. At Åkhultmyren, there was a similar reduction in pH, but the changes in the plant composition also indicated increased nutrient levels and a drier mire surface. Therwere large changes in species composition on Åkhultmyren. For instance Scheuchzeria palustris had disappeared from the investigated area. Further, the cover of Scots pine (Pinusylvestris) had increased, which can be explained by a changed ground-water table regime. Monitoring of pines growing on a bog over a ten-year period showed that pines growing higher above the ground-war table had higher survival than lower-growing pines. Experimental addition of nitrogen during 3-4 years reduced Sphagnum growth in bogs and poor fens repressenting a wide range of ambient nitrogen deposition. A changed interspecific competitive relation was found between S. lindbergand S. balticum when increasing nitrogen influx, but the competitive relations between two hummock-growing species pairs did not change in a three-year nitrogen fertilization study. Sulphur additiodid not affect the production or length increment in S. balticum. An increased temperature reduced Sphagnum growth, but there were no indications of altered competitive relationshipbetween hummock and hollow inhabiting Sphagnum species in a four-year experiment.

突變生成(mutagenesis)的方式有許多種，其中insertional mutagenesis為果蠅上常使用建立突變株的方式，本篇論文利用p[GawB]隨機插入果蠅genome中產生大量突變株，並篩選出會影響壽命的突變果蠅M2。進一步的實驗發現M2果蠅為Vha16-1基因的突變，並造成其mRNA表現量的下降，且在低卡路里(5% yeast、5% dextrose)與高卡路里(15% yeast、15% dextrose)的環境下homozygous mutant果蠅皆有減少平均壽命的現象。 Vha16-1所表現的蛋白為Vacuolar-type H+-ATPase (V-ATPase)上的subunit c，V-ATPase主要的功能為藉由消耗ATP來運送氫離子，並可調節胞器或胞外腔室的酸鹼平衡。V-ATPase主要表現在果蠅腸道的copper cell上，此細胞的功能類似於哺乳動物的胃壁細胞(parietal cells)，與胃酸的分泌有關，我們發現M2 homozygous mutant果蠅因Vha16-1基因的缺失而有減少腸道酸化的情形發生，符合我們觀察到其在腸道上的表現。此一現象亦在另一株突變果蠅Vha16-1EP2372上加以證實。先前研究顯示果蠅腸道酸鹼平衡的破壞會影響到對養分的吸收，而Vha16-1的缺失亦導致M2果蠅體重與三酸甘油酯的上升，並增加對飢餓的耐受性，而這些代謝上的變化並不會改變M2果蠅對食物的攝取量或者生育能力。綜合這些實驗結果，我們推測Vha16-1基因的缺失會改變腸道功能，並影響果蠅體內代謝的狀態，表現出類似肥胖(obesity)的性狀，而終導致平均壽命的縮短。 / Mutagenesis can be induced by many ways and one of the most common approaches used in Drosophila is insertional mutagenesis. In this study, we screened pGawB insertion lines and identified M2 as a novel mutant with affected lifespan. The mutant allele of M2 carried a pGawB inseration at the 5’ end of the Vha16-1 gene, which caused a reduced Vha16-1 mRNA expression level and a shorten lifespan in homozygous mutants under both low calorie (5% yeast and 5% dextrose) and high calorie (15% yeast and 15% dextrose) foods. Vha16-1 encodes the c subunit of the Vacuolar-type H+-ATPase (V-ATPase) which is known to regulate pH homeostasis by pumping protons across organelle and plasma membranes. V-ATPase is highly expressed by the Copper cells which are located at the Drosophila middle midgut and functionally similar to the gastric acid producing parietal cells in mammals. Along the same line, we found that Vha16-1 pGawB drives GFP reporter was observed along the Drosophila gastrointestinal tract. M2 as well as the other Vha16-1 hypomorphic mutant line, EP2372, also showed reduced midgut acidification. This disrupted pH homeostasis in the Drosophila midgut region may be associated with increased body weight, triglyceride, and starvation resistance that observed in M2 mutants. The feeding behavior and reproductive function, however, were not affected in M2 mutant flies. In summary, our data suggested Vha16-1 deficits may alter normal intestinal function or internal metabolic status that ultimately induces obesity phenotypes with reduced lifespan.