Glycerol and other polyols are used as osmoprotectants by many organisms. Several yeasts and other fungi can take up glycerol by proton symport. To identify genes involved in active glycerol uptake in Saccharomyces cerevisiae we screened a deletion mutant collection comprising 321 genes encoding proteins with 6 or more predicted transmembrane domains for impaired growth on glycerol medium. Deletion of STL1, which encodes a member of the sugar transporter family, eliminates active glycerol transport. Stl1p is present in the plasma membrane in S. cerevisiae during conditions where glycerol symport is functional. Both the Stl1 protein and the active glycerol transport are subject to glucose-induced inactivation, following identical patterns. Furthermore, the Stl1 protein and the glycerol symporter activity are strongly but transiently induced when cells are subjected to osmotic shock. STL1 was heterologously expressed in Schizosaccharomyces pombe, a yeast that does not contain its own active glycerol transport system. In S. pombe, STL1 conferred the ability to take up glycerol against a concentration gradient in a proton motive force-dependent manner. We conclude that the glycerol proton symporter in S. cerevisiae is encoded by STL1. INTRODUCTIONGlycerol, a C 3 polyalcohol, is an important intermediate in energy metabolism in both prokaryotes and eukaryotes. It has long been used for therapeutic and industrial processes. Aspects of glycerol metabolism are also important in biotechnology, e.g., for bio-alcohol production yields or wine smoothness. Essential roles of glycerol in basic biochemical aspects have been extensively studied in several yeasts and fungi. These include biosynthesis of glycerophospholipid and triacylglycerol from glycerol 3-phosphate and dihydroxyacetone phosphate (Kohlwein et al., 1996;Mü llner and Daum, 2004), redox balance (Ansell et al., 1997;Valadi et al., 2004), osmoadaptation (reviewed by Hohmann, 2002, oxidative stress protection (Påhlman et al., 2001), and response to heat shock (Siderius et al., 2000). Responses to elevated temperatures and high osmolarity involve several signaling pathways including the protein kinase C pathway and the HOG pathway, which regulates intracellular levels of glycerol (Hohmann, 2002;Wojda et al., 2003).In cells ranging from mammals (Lang et al., 1998) to archea (Kempf and Bremer, 1998), osmolytes play an important role in the response to osmotic stress caused by low water availability in environments as diverse as poorly irrigated soils or high-sugar musts. In eukaryotic microorganisms like algae or yeasts, polyols, primarily glycerol, act as osmolytes (reviewed by Brown, 1977 andWang et al., 2001). Their production, consumption and retention are consequently tightly regulated and dynamic processes (reviewed by Hohmann, 2002). Magnaporthe grisea (rice blast) a phytopathogenic fungus with a strong impact on world economy, accumulates glycerol, which allows the penetration of the appressorium into the plant host cell (Thines et al., 2000). Glycerol has also...

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Most cases of candidiasis have been attributed to C. albicans, but recently, non- Candida albicans Candida (NCAC) species have been identified as common pathogens. The ability of Candida species to form biofilms has important clinical repercussions due to their increased resistance to antifungal therapy and the ability of yeast cells within the biofilms to withstand host immune defenses. Given this clinical importance of the biofilm growth form, the aim of this study was to characterize biofilms produced by three NCAC species, namely C. parapsilosis, C. tropicalis and C. glabrata. The biofilm forming ability of clinical isolates of C. parapsilosis, C. tropicalis and C. glabrata recovered from different sources, was evaluated by crystal violet staining. The structure and morphological characteristics of the biofilms were also assessed by scanning electron microscopy and the biofilm matrix composition analyzed for protein and carbohydrate content. All NCAC species were able to form biofilms although these were less extensive for C. glabrata compared with C. parapsilosis and C. tropicalis. It was evident that C. parapsilosis biofilm production was highly strain dependent, a feature not evident with C. glabrata and C. tropicalis. Scanning electron microscopy revealed structural differences for biofilms with respect to cell morphology and spatial arrangement. Candida parapsilosis biofilm matrices had large amounts of carbohydrate with less protein. Conversely, matrices extracted from C. tropicalis biofilms had low amounts of carbohydrate and protein. Interestingly, C. glabrata biofilm matrix was high in both protein and carbohydrate content. The present work demonstrates that biofilm forming ability, structure and matrix composition are highly species dependent with additional strain variability occurring with C. parapsilosis.

Candida albicans accumulates large amounts of the polyols glycerol and D-arabitol when the cells are exposed to physiological conditions relevant to stress and virulence in animals. Intracellular concentrations of glycerol are determined by rates of glycerol production and catabolism and of glycerol uptake and efflux through the plasma membrane. We and others have studied glycerol production in C. albicans, but glycerol uptake by C. albicans has not been studied. In the present study, we found that [14 C]glycerol uptake by C. albicans SC5314 was (i) accumulative; (ii) dependent on proton-motive force; (iii) unaffected by carbon source; and (iv) unaffected by large molar excesses of D-arabitol or other polyols. The respective K m and V max values were 2.1 mM and 460 mmol h "1 (g dry wt) "1 in glucose medium and 2.6 mM and 268 mmol h "1 (g dry wt) "1 in glycerol medium. To identify the C. albicans glycerol uptake protein(s), we cloned the C. albicans homologues of the Saccharomyces cerevisiae genes GUP1 and STL1, both of which are known to be involved in glycerol transport. When multicopy plasmids encoding C. albicans STL1, C. albicans STL2 and C. albicans GUP1 were introduced into the corresponding S. cerevisiae null mutants, the transformants all acquired the ability to grow on minimal glycerol medium; however, only S. cerevisiae stl1 null mutants transformed with C. albicans STL1 actively took up extracellular [ 14 C]glycerol. When both chromosomal alleles of C. albicans STL1 were deleted from C. albicans BWP17, the resulting stl1 null mutants grew poorly on minimal glycerol medium, and their ability to transport [ 14 C]glycerol into the cell was markedly reduced. In contrast, deletion of both chromosomal alleles of C. albicans STL2 or of C. albicans GUP1 had no significant effects on [ 14 C]glycerol uptake or the ability to grow on minimal glycerol medium. Northern blot analysis indicated that C. albicans STL1 was expressed in both glucose and glycerol media, conditions under which we detected wild-type active glycerol uptake. Furthermore, STL1 was highly expressed in salt-stressed cells; however, the stl1 null mutant was no more sensitive to salt stress than wild-type controls. We also detected high levels of STL2 expression in glycerol-grown cells, even though deletion of this gene did not influence glycerol uptake activity in glycerol-grown cells. We conclude from the results above that a plasma-membrane H + symporter encoded by C.albicans STL1 actively transports glycerol into C. albicans cells.

In the present work, the effect of twelve rootstocks on fruit quality of the nucellar clone IAC-5 of 'Tahiti' lime, (Citrus latifolia Tanaka) and the influence of fruit position on tree in fruit quality was evaluated in the Citrus Experimental Station of Bebedouro (EECB), located in the Bebedouro county, state of São Paulo, Brazil. A 8.0 x 5.0m planting frame was utilized. The evaluated rootstocks were: 'Carrizo' citrange (C. sinensis (L.) Osbeck x Poncirus trifoliata (L.) Raf.); the hybrids 'Rangpur' lime x 'Swingle' citrumello (C. limonia Osbeck x P. trifoliata Raf) and 'Changsha' x 'English Small'(C. sunki Hort. ex Tan. x P. trifoliata Raf.); the mandarins 'Sun Chu Sha Kat' (C. reticulata Blanco) and 'Sunki' (C. sunki Hort. ex Tanaka); the 'Rangpur' limes 'Cravo Limeira' and ' Cravo FCAV' (C. limonia Osbeck); the 'Swingle' citrumello (P. trifoliata Raf. x C. paradisi Macf.); the 'Orlando' tangelo (C. reticulata Blanco x C. paradisi Macf.) and the trifoliates cvs. 'Rubidoux', 'FCAV' and 'Flying Dragon' (P. trifoliata Raf.). The experiment was arranged in a randomized block design, with twelve treatments, six replicates and one plant per plot. The rootstocks induced differences in fruit quality; however, all the evaluated quality characteristics were within the values considered as normal and acceptable for the variety, constituting good alternative rootstocks for the 'Rangpur' lime. Additionally, the fruit position in the plant (northeastern or southwestern) had a significant influence on the external fruit color regardless of the rootstock.

The enzyme pectinmethylesterase (PME) from acerola was extracted and purified by gel anion-exchange chromatography (Q Sepharose) and filtration on Sephadex G-100. The results showed two different PME isoforms (PME1 and PME2), with molecular masses of 25.10 and 5.20 kDa, respectively. PME1 specific activity increased by 9.63% after 60 min incubation at 98 • C, while PME2 retained 66% of its specific activity under the same conditions. The K m values of PME1, PME2 and concentrated PME were 0.94, 0.08 and 0.08 mg mL −1 , respectively. The V max value of PME1, PME2 and concentrated were 204.08, 2, 158.73 and 2.92 µmol min −1 mg −1 protein, respectively.

--Origin and importance. Acerola, or Malpighia emarginata D.C., is native to the Caribbean islands, Central America and the Amazonian region. More recently, it has been introduced in subtropical areas (Asia, India and South America). The vitamin C produced by acerola is better absorbed by the human organism than synthetic ascorbic acid. Exportation of acerola crops is a potential alternative source of income in agricultural businesses. In Brazil, the commercial farming of acerola is quite recent. Climatic conditions. Acerola is a rustic plant. It can resist temperatures close to 0°C, but it is well adapted to temperatures around 26°C with rainfall between (1200 and 1600) mm per year. Fruit characteristics. Acerola fruit is drupaceous, whose form can vary from round to conic. When ripe, it can be red, purple or yellow. The fruit weight varies between (3 and 16) g. Maturation. Acerola fruit presents fast metabolic activity and its maturation occurs rapidly. When commercialised in ambient conditions, it requires fast transportation or the use of refrigerated containers to retard its respiration and metabolism partially. Production and productivity. Flowering and fruiting are typically in cycles associated with rain. Usually, they take place in 25-day cycles, up to 8 times per year. The plant can be propagated by cuttings, grafting or seedlings. Harvest. Fruits produced for markets needs to be harvested at its optimal maturation stage. For distant markets, they need to be packed in boxes and piled up in low layers; transportation should be done in refrigerated trucks in relatively high humid conditions. Biochemical constituents. Acerola is the most important natural source of vitamin C [(1000 to 4500) mg·100 -1 g of pulp], but it is also rich in pectin and pectolytic enzymes, carotenoids, plant fibre, vitamin B, thiamin, riboflavin, niacin, proteins and mineral salts. It has also shown active anti-fungal properties. Products and market. Acerola is used in the production of juice, soft drinks, gums and liqueurs. The USA and Europe are great potential markets. In Europe, acerola extracts are used to enrich pear or apple juices. In the USA, they are used in the pharmaceutical industry. Conclusions. The demand for acerola has increased significantly in recent years because of the relevance of vitamin C in human health, coupled with the use of ascorbic acid as an antioxidant in food and feed. Acerola fruit contains other significant components, which are likely to lead to a further increase in its production and trade all over the world.Brazil / Malpighia emarginata / fruits / proximate composition / uses / world markets Acérola : importance, conditions de culture, production et aspects biochimiques.Résumé --Origine et importance. L'acérola, ou Malpighia emarginata D.C., est originaire des îles Caraï-bes, d'Amérique centrale et d'Amazonie. Cette plante a été introduite récemment en zones subtropicales (Asie, Inde, Amérique du Sud). La vitamine C produite par l'acérola est mieux absorbée par l'organisme humain qu...

RESUMO -A pitaya é uma cactácea de sub-bosque, originária de florestas tropicais do México e das Américas Central e do Sul, pouco estudada no Brasil, principalmente quanto à sua resposta à intensidade luminosa e adubação. Nesse sentido, realizou-se um experimento objetivando avaliar crescimento e desenvolvimento inicial da pitaya em função da intensidade luminosa e adubação orgânica. O delineamento experimental adotado foi em blocos casualizados, com tratamentos distribuídos em esquema fatorial 5 x 3, referentes, respectivamente, aos níveis de adubação orgânica (0; 5; 10; 20 e 30 L de esterco bovino cova -1 ) e aos percentuais de luz (0; 50 e 75% de sombreamento), com quatro repetições. Foram avaliados semanalmente diâmetro do cladódio (mm), altura de estacas (cm) e comprimento do ramo secundário (cm); ao final do experimento, massa fresca da parte aérea e massas secas de raiz e parte aérea (g), sendo que para as variáveis mensuradas, semanalmente, foram calculados os respectivos incrementos percentuais semanais. Segundo os resultados do presente trabalho, no cultivo da pitaya, é necessário o uso de cobertura contra a incidência direta dos raios solares, onde as estruturas com 50% ou 75% de luminosidade podem ser usadas. O fornecimento de 20 L cova -1 de esterco bovino pode ser adotado como quantitativo no preparo de covas de pitaya, nas condições de clima e solo de Bom Jesus-PI. Termos para indexação: Hylocereus undatus, esterco bovino, sombreamento. ORGANIC FERTILIZING AND LIGHT INTENSITY ON INITIAL GROWTH AND DEVELOPMENT OF PITAYA IN BOM JESUS, STATE OF PIAUI, BRAZILABSTRACT -Pitaya is a hemiepiphytic cactus native from tropical rainforests of Mexico and Central and South America little studied in Brazil especially in relation to light intensity and fertilizing. In this way, an experiment was realized in 2007 aiming to evaluate the initial growth and development as a function of light intensity and organic fertilizing. A complete randomized blocks design was adopted with treatments distributed in a factorial arrangement 5 x 3 referring respectively to organic fertilizing levels (0, 5, 10, 20 e 30 L of bovine manure plant -1 ) and light percentage (0, 50 e 75% of shade), with four repetitions. Stem diameter, plant height and length of the secondary shoot were evaluated weekly, and root dry mass and shoot fresh mass were determined at the end of the experiment. For the week variables, the respective week increases were measured. For pitaya cultivation it is necessary a covering system, where 50% or 75% of light intensity could be used. The dose of 20 L plant -1 of bovine manure could be adopted as quantitative for the preparation of pitaya caves under soil and climate conditions of Bom Jesus, State of Piaui, Brazil.