Pullulation bactérienne de l'intestin grêle [Small intestine bacterial overgrowth]

Small intestine bacterial overgrowth (SIBO) is a condition characterised by nutrient malabsorption and excessive bacteria in the small intestine. It typically presents with diarrhea, flatulence and a syndrome of malabsorption (steatorrhea, macrocytic anemia). However, it may be asymptomatic in the eldery. A high index of suspicion is necessary in order to differentiate SIBO from other similar presenting disorders such as coeliac disease, lactose intolerance or the irritable bowel syndrome. A search for predisposing factor is thus necessary. These factors may be anatomical (stenosis, blind loop), or functional (intestinal hypomotility, achlorydria). The hydrogen breath test is the most frequently used diagnostic test although it lacks standardisation. The treatment of SIBO consists of eliminating predisposing factors and broad-spectrum antibiotic therapy.

Purification and characterization of (Na+ + K+)-ATPase from toad kidney

This report describes the partial purification and the characteristics of (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) from an amphibian source. Toad kidney microsomes were solubilized with sodium deoxycholate and further purified by sodium dodecyl sulphate treatment and sucrose gradient centrifugation, according to the methods described by Lane et al. [(1973) J. Biol. Chem. 248, 7197--7200], Jørgensen [(1974) Biochim. Biophys. Acta 356, 36--52] and Hayashi et al. [(1977) Biochim. Biophys. Acta 482, 185--196]. (Na+ + K+)-ATPase preparations with specific activities up to 1000 mumol Pi/mg protein per h were obtained. Mg2+-ATPase only accounted for about 2% of the total ATPase activity. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed three major protein bands with molecular weights of 116 000, 62 000 and 26 000. The 116 000 dalton protein was phosphorylated by [gamma-32P]ATP in the presence of sodium but not in the presence of potassium. The 62 000 dalton component stained for glycoproteins. The Km for ATP was 0.40 mM, for Na+ 12.29 mM and for K+ 1.14 mM. The Ki for ouabain was 35 micron. Temperature activation curves showed two activity peaks at 37 degrees C and at 50 degrees C. The break in the Arrhenius plot of activity versus temperature appeared at 15 degrees C.

Quantitative analysis of postnatal neurogenesis and neuron number in the macaque monkey dentate gyrus

The dentate gyrus is one of only two regions of the mammalian brain where substantial neurogenesis occurs postnatally. However, detailed quantitative information about the postnatal structural maturation of the primate dentate gyrus is meager. We performed design-based, stereological studies of neuron number and size, and volume of the dentate gyrus layers in rhesus macaque monkeys (Macaca mulatta) of different postnatal ages. We found that about 40% of the total number of granule cells observed in mature 5-10-year-old macaque monkeys are added to the granule cell layer postnatally; 25% of these neurons are added within the first three postnatal months. Accordingly, cell proliferation and neurogenesis within the dentate gyrus peak within the first 3 months after birth and remain at an intermediate level between 3 months and at least 1 year of age. Although granule cell bodies undergo their largest increase in size during the first year of life, cell size and the volume of the three layers of the dentate gyrus (i.e. the molecular, granule cell and polymorphic layers) continue to increase beyond 1 year of age. Moreover, the different layers of the dentate gyrus exhibit distinct volumetric changes during postnatal development. Finally, we observe significant levels of cell proliferation, neurogenesis and cell death in the context of an overall stable number of granule cells in mature 5-10-year-old monkeys. These data identify an extended developmental period during which neurogenesis might be modulated to significantly impact the structure and function of the dentate gyrus in adulthood.

Histoire du Saint-Graal, et Histoire de Merlin, par ROBERT DE BORON.

Contient : Histoire du Saint-Graal, par ROBERT DE BORON. « [C]hil ki se tient et juge au plus peceor de tous, mande salus... » [Le Saint Graal, éd. Hucher, II, 3, note] ; « ... et commenche messire ROBERS en tel manière [Ibid., III, 303], comme vos poerés oïr, s'il est ki le vos die. Or nous consaut Sainte Marie. Explicit li commencemens de l'estoire del s. Graal, et chi après vient l'estoire de Merlin. Dieu nous maint tous à boine fin. Amen. » [Cf. l'explicit dans le ms. franç. 95] ; Histoire de Merlin, par ROBERT DE BORON. « Mout fut iriés li anemis, quant nostre sires ot estei en enfer... » ; «... si come li contes le vous devisera cha avant. Explicit l'enserrement de Merlin. Diex nous maint tous à boine fin. Amen »

Vies de saints, en français.

Contient : Vie de S. Laurent, en vers. « Maistre, a cest besoing vus dreciez... » ; Assomption Notre-Dame, par Hermann de Valenciennes (attribuée ici à « Willemme »), en vers. « Seignors, or escutez, que Deu vus beneïe... » ; Vision de S. Paul, en vers. « Seignors freres, ore escoutez... » ; Vie de Ste Marie l'Égyptienne, en vers. « Oez, seignors, une raisun. ». ; Vie de S. Alexis, en vers. « Bons fu li siecles al tens ancienor... » ; Vie de S. Jean l'Évangéliste, en prose. « Le secunt travail as Crestiens, après Nerun... » ; Vie de S. Jean-Baptiste, en prose. « Al tens Herode le rei de Judée fu un proveire... » ; « Vie de S. Barthélemy. « Ceo cuntent ceus qui sevent deviser les parties del munde... » ; Passion de S. Pierre et S. Paul, en prose. « Al tens Nerun Cesar esteient a Rome... » ; Du jugement de Dieu, en vers. « Seignors, oez raisun gloriose et saintisme... » ; Sermon, en sixains, sur le jugement de Dieu ; Évangile de Nicodème. « Ceo avint al quinzime an que Tyberie Cesar aveit esté enpereor... » ; Sermon du siècle, de Guichart de Beaulieu, en vers. « Entendez vers mei, les pétiz et les granz... » ; Vie de Ste Marie-Madeleine, en vers, par « Willieme » ; Enseignement sur le Pater, en prose. « A son treschier frere. Mun cher frere, sachez ke home tant cum il entent... » ; De la confession, en prose. « Ki voldra bien e beau vestu aparer devant la face Jhesu... » ; Vie de Notre-Dame, par « Guillame, » en vers ; Dit du besant de Dieu, par « Guillame », en vers. « Pur ceo que jeo ne voil muscier... » ; Des trois ennemis de l'homme, par Guillaume, en vers. « [T]reis moz qui me sont enchargez... » ; Histoire de Tobie, dédiée à « Guillelme... del iglise Sainte Marie de Keneille wourthe en Ardene », en vers. « [C]il qui seme bone semence... » ; Vie de Ste Marguerite, en vers ; Sermons, en prose ; I « Donavit illi nomen quod est super omne nomen, etc. Seint Pol li apostre dit de nostre Salveor... » ; II « Dixit Dominus ad Jesum filium Naue... Dist nostre Seignor a Jesu le fiz Nave, qui ert ministre Moysi... » ; III « Misit Deus exploratores in abscondito... Ceo fait a entendre en romanz que Jesu Nave, enveiad... » ; IVCum autem esset Jesus in agro urbis Jerico... Ceo conte l'estoire de la lei, quand Jesu fud en champ de Jerico... » ; V « Tulit autem unus ex filiis Israel aliquid de anathemate Jerico... Ceo dit l'estoire que uns hoem de la mesnée Israel... » ; La Passion, extraite de la Bible en vers de Hermann de Valenciennes ; Chanson, avec musique notée. « Margot, Margot, greif sunt ly mau d'amer, très duce Margot... »

Français 1536

Contient : 1° « Miracles de Nostre. Dame », par « WAUTIER DE COINSI » ; Chansons en l'honneur de la Vierge, avec notation ; « Amours, ki set bien encanter... » ; « Ki ki fache rotruenge nouvele... » ; « Rome chelestre... » ; « Talens m'est pris orendroit... » ; « Reforchier m'estuet ma vois... » ; « Quant ches floretes florir voi... » ; « Pour conforter mon cuer et mon corage... » ; Miracles ; « [P]our chaus esbatre et deporter... » ; « Un bel miracle vous eschite... » ; « Un miracle truis d'un prevoire... » ; « A Chartres fu, che truis, uns clers... » ; « Uns moines fu d'une abeïe... » ; « Pour pluisors cuers plus enflamber... » ; « [U]n haut miracle mult pitex... » ; « Tout li miracle Nostre Dame... » ; « Une abeesse fu jadis... » ; « Entendes tout, faites silenche... » ; « [Tene]s silenche, [bele]s gens... » ; « Un brief miracle mult aoine... » ; « [Si com] mes livres [me] tesmogne... » ; « [Un] miracle vous [vo]el redire... » ; « Mes livres me dist et revele... » ; « En escrit truis k'en l'abeïe... » ; « A chaus ki aiment douchement... » ; « A la loenge de la Vierge... » ; « Ichi apres voel metre en brief... » ; [Se pres de moi vous voules traire...] ; «... De madame sainte Marie... ». — Manquent les cinq premiers vers ; « Quelke d'oïr aves talent... » ; « [Q]ueke talent aves d'oïr... » ; « En escrit truis ke pres d'Orliens... » ; « Entendes tuit, et clerc et lai... » ; « Quoike volentés me semonst... » ; « [Un] miracle [v]oel rechiter... » ; « Pour che qu'iseuse est mors à l'ame... » ; « [I]l fu.I. muit biax damoisiaus... » ; « Bien est ke nos le bien dions... » ; « Un archeveske ot à Tolete... » ; « [A B]oorges che [t]ruis lisant... » ; « Il fu, ce truis, uns chevaliers... » ; « Chele en cui prist humanité... » ; « A le loenge glorieuse... » ; « [Que] de memore ne decaie... » ; Prologue du second livre ; Chansons en l'honneur de la Vierge, avec notation ; « Pour la puchele en chantant me deport... » ; « Mere Diu, virge senée... » ; « L'amours dont sui espris... » ; « D'une amour coie et serie... » ; « Hui matin à l'ajournée... » ; Suite des miracles ; « Asses saves ke mult lo on... » ; « Or entendes ça en cest fuel... » ; « [As sa]ges dist [et f]ait savoir... » ; « [I]chi me prent, ichi m'aart... » ; « Vous, damoiseles, et vous, dames... » ; « Un miracle trop mervellex... » ; « [Au t]ans ke de la [ci]té noble... » ; « Tant truis escrit, foi ke doit m'ame... » ; « Ki bons livraires veut cherkier... » ; « [O]n doit mult volentiers oïr... » ; « Conter vos voel d'un home lai... » ; « La douce mere au creatour... » ; « Se Dix m'aït hui et demain... » ; « Ichi apres voel remauller... » ; « Sainte Escriture nous esclaire... » ; « Anchois ke hors du livre issons... » ; « Ki veut oïr vers moi se traie... » ; « Chele ki est de tel maniere... » ; « Mes livres me dit et narrat... » ; « Ki veut oïr, qui veut entendre... » ; « Vous ki ames de cuer entier... » ; « Quant issus sui et eschapés... » ; « Gautiers, ki est de cors et d'ame... » ; « Men chief m'a tout resvertué... » ; 2° « Les Salus à la tres glorieuse Virge Marie », par le même ; 3° Paraphrase du psaume Eructavit

聖事禮典Sheng shi li dian.

Manvale ad Sacramenta ministranda ivxta ritvm sanctæ romanæ ecclesiæ sinicè redditvm a P. Lvdovico Bvglio Soc. Iesv tipis editvm Pěkińg in Collegio ejvsdem Soc. Anno 1675 et transcriptvm Cantone anno Dñi 1713.Au verso du titre latin, nom du traducteur et autorisation du P. Verbiest.150 feuillets.

Chronique, histoires de la Bible, Vies de saints, Sermons de MAURICE DE SULLY, en français.

Contient : Chronique abrégée depuis la naissance de Jésus-Christ jusqu'en 1304. Cf. Hist. litt. de la France, t. XXXII, p. 240 ; Recueil d'histoires tirées de la Bible : « Bien doivent metre lor entendement tuit cil ki ont sens... » (Genèse, Juges, Rois et Macchabées) ; Vie de Jésus-Christ: « Quant li tans fu raemplis... » ; Vies de saints abrégées, en français ; Sermons de MAURICE DE SULLY, en français. — Le premier de ces sermons débute : « Dominus ac salvator noster, dilectissimi, post passionem salutiferam... Dicit ei pasce oves meas. — Seignor provoire, ceste parole ne fu mie seulement dite à mon signor S. Pierre... » ; « Ce est la ramembrance combien li Crestien furent en servage o les Sarasins. » (Jusqu'en 1290. — Écriture postérieure.) — A la fin (fol. 375): « Ssm scrhtpr tblhs mpsstrbt mfb lhttfrb qsbl». » = Sum scriptor talis mosstrat mea littera qualis

Recueil d'anciennes poésies françaises.

Contient : Mériadeuc ou le Chevalier aux deux épées. (Cf. Histoire littéraire, XXX, 237) ; Roman du Chevalier au lion, par CHRÉTIEN DE TROYES ; Roman d'Énéas. — Incomplet des 1,729 premiers vers ; ms. E de l'édition de Salverda De Grave (1892) ; Fragment du roman de Brut, par WACE ; Enfances Oger le Danois ; Roman de Fierabras ; Fableaux. Du vilain à la couille noire. « Un fablel vous voel commenchier... » ; « Du prestre ki abevete. Ichi après vous voel conter... » ; « Des III. avules. Unes matere contera[i]... » ; « Du vallet qui d'aise a malaise se mel. Voulés vous oïr du vallet... » ; Les quatre souhaits « de S. Martin. Un preudomme ut en Normendie... » (Incomplet de la fin) ; Dame Aubrée. (Incomplet du début) ; « Du lait de l'ombre. Je ne voel pas des aviser... » ; « Ch'est du vilain ki quida estre mors. Se fabliaus puet vérités estre... » ; « Ch' est du lai d'infier. Ahay! ha hai! je suis venus... » (Incomplet de la fin) ; « Li jouenes maires du Hamiel. » (Incomplet du début.) — Ibid. « Ch'est du priestre c'on portet. Du priestre vous di et recort... » ; « Du prestre et du chevalier. Traiiés en cha, s'oiiés i. conte, Si com Milles d'Amiens le conte... » ; De la mâle dame qui fut escoillée. « Uns riches chevaliers estoit... » ; « Ch'est du songe. En songes doit fables avoir... Voie de Paradis de RAOUL DE HOUDENC ; « Du noble lion. Li lions c'on apele nobles... » ; « De mâle Honte. En Engletere fu manans... » ; « Ch'est Ysopés en romans. Cil qui sevent de l'Escripture... » Fables de MARIE DE FRANCE. (103 fables) ; « De le femme qui cunquie sen baron. Je vous dirai s'il vous siet... » (Incomplet de la fin) ; On lit au dernier fol. 302 : « En ce volume cy y a quatre livres en rime, c'est assavoir : du roy Artus, des XII Peres de France, du Chevalier à deux espéez et des Fables de Ysopet ; lequel est monsr. Charles de Croy, comte de Chimay. CHARLES »

The study of ligand binding specificities of the lipid binding proteins : recombinant human a-tocopherol transport protein (a-ttp), supernatant protein factor (spf) and S. cerevisiae Sec 14p for vitamin e (rrr-a-tocopherol) and other hydrophobic ligands.

One of the various functions of proteins in biological systems is the transport of small molecules, for this purpose proteins have naturally evolved special mechanisms to allow both ligand binding and its subsequent release to a target site; a process fundamental to many biological processes. Transport of Vitamin E (a-tocopherol), a lipid soluble antioxidant, to membranes helps in the protection of polyunsaturated fatty acids against peroxidative damage. In this research, the ligand binding characteristics of several members of the CRALTRIO family of lipid binding proteins was examined; the recombinant human a-Tocopherol Transfer Protein (a-TIP), Supernatant Protein Factor (SPF)ffocopherol Associated Protein (TAP), Cellular Retinaldehyde Binding Protein (CRALBP) and the phosphatidylinositol transfer protein from S. cerevisiae Sec 14p. Recombinant Sec 14p was expressed and purified from E. coli for comparison of tocopherol binding to the two other recombinant proteins postulated to traffic a-tocopherol. Competitive binding assays using [3H]-a-tocopherol and Lipidex-l000 resin allowed determination of the dissociation constants ~) of the CRAL-TRIO proteins for a-tocopherol and - 20 hydrophobic ligands for evaluation of the possible biological relevance of the binding interactions observed. The KIs (nM) for RRR-a-tocopherol are: a-TIP: 25.0, Sec 14p: 373, CRALBP: 528 and SPFffAP: 615. This indicates that all proteins recognize tocopherol but not with the same affinity. Sec 14p bound its native ligand PI with a KI of381 whereas SPFffAP bound PI (216) and y-tocopherol (268) similarly in contrast to the preferential binding ofRRR-a-tocopherol by a-TIP. Efforts to adequately represent biologically active SPFff AP involved investigation of tocopherol binding for several different recombinant proteins derived from different constructs and in the presence of different potential modulators (Ca+2, Mg+2, GTP and GDP); none of these conditions enhanced or inhibited a-tocopherol binding to SPF. This work suggests that only aTTP serves as the physiological mediator of a-tocopherol, yet structural homology between proteins allows common recognition of similar ligand features. In addition, several photo-affmity analogs of a-tocopherol were evaluated for their potential utility in further elucidation of a-TTP function or identification of novel tocopherol binding proteins.

The osmoadaptive response of the wine yeast Saccharomyces cerevisiae K1-V1116 during icewine fermentation

The adapted metabolic response of commercial wine yeast under prolonged exposure to concentrated solutes present in Icewine juice is not fully understood. Presently, there is no information regarding the transcriptomic changes in gene expression associated with the adaptive stress response ofwine yeast during Icewine fermentation compared to table wine fermentation. To understand how and why wine yeast respond differently at the genomic level and ultimately at the metabolic level during Icewine fermentation, the focus ofthis project was to identify and compare these differences in the wine yeast Saccharomyces cerevisiae KI-Vll16 using cDNA microarray technology during the first five days of fermentation. Significant differences in yeast gene expression patterns between fermentation conditions were correlated to differences in nutrient utilization and metabolite production. Sugar consumption, nitrogen usage and metabolite levels were measured using enzyme assays and HPLC. Also, a small subset of differentially expressed genes was verified using Northern analysis. The high osmotic stress experienced by wine yeast throughout Icewine fermentation elicited changes in cell growth and metabolism correlating to several fermentation difficulties, including reduced biomass accumulation and fermentation rate. Genes associated with carbohydrate and nitrogen transport and metabolism were expressed at lower levels in Icewine juice fermenting cells compared to dilute juice fermenting cells. Osmotic stress, not nutrient availability during Icewine fermentation appears to impede sugar and nitrogen utilization. Previous studies have established that glycerol and acetic acid production are increased in yeast during Icewine fermentation. A gene encoding for a glycerollW symporter (STL1) was found to be highly expressed up to 25-fold in the i Icewine juice condition using microarray and Northern analysis. Active glycerol transport by yeast under hyperosmotic conditions to increase cytosolic glycerol concentration may contribute to reduced cell growth observed in the Icewine juice condition. Additionally, genes encoding for two acetyl CoA synthetase isoforms (ACSl and ACS2) were found to be highly expressed, 19- and II-fold respectively, in dilute juice fermenting cells relative to the Icewine juice condition. Therefore, decreased conversion of acetate to acetyl-CoA may contribute to increased acetic acid production during Icewine fermentation. These results further help to explain the response of wine yeast as they adapt to Icewine juice fermentation. ii

Metabolite changes during Riesling icewine fermentation when yeast micronutrients are used /

Icewine is an intensely s\veet dessert \vine fermented from the juice of naturally frozen grapes. Icewine fermentation poses many challenges such as failure to reach desired ethanol levels and production of high levels of volatile acidity in the fonn of acetic acid. This study investigated the impact of micronutrient addition (GO-FERM® and NATSTEP®) during the rehydration stage of the commercial \vine yeast Saccharomyces cerevisiae KI-VIII6 during Ice\vine fermentation. Sterile-filtered and unfiltered Riesling Ice\vine juice was inoculated \vith yeast rehydrated under four different conditions: in water only; with GO-FERM®; with NATSTEP®; or the combination of both micronutrient products in the rehydration water. Using sterile-filtered Icewine juice, yeast rehydration had a positive impact of reducing the rate of acetic acid produced as a function of sugar consumed, reducing the ratio of acetic acid/ethanol and reducing the ratio of acetic acid/glycerol. In the sterile-filtered fermentation, yeast rehydrated with micronutrients generated 9-times less acetic acid per gram of sugar in the first 48 hours compared to yeast rehydrated only \vith water and resulted in a 17% reduction in acetic acid in the final \vine \vhen normalized to sugar consumed. However, the sterile-filtered fermentations likely became stuck due to the overc1arification of the juice as evidenced from the low sugar consumption (117 gIL) that could not be completely overcome by the micronutrient treatments (144 gIL sugar consumed) to reach a target ethanol of IO%v/v. Contrary to \vhat \vas observed in the sterile-filtered treatements, using unfiltered Ice\vine juice, yeast micronutrient addition had no significant impact of reducing the rate of acetic acid produced as a function of sugar consumed, reducing the ratio of acetic acid/ethanol and reducing the ratio of acetic acid/glycerol. However, in the unfiltered fermentation, micronutrient addition during yeast rehydration caused a reduction in the acetic acid produced as a function of sugar consumed up to 150 giL sugar consumed.. In contrast to the sterile-filtered fermentations, the unfiltered fermentations did not become stuck as evidenced from the higher sugar consumption (l47-174g1L). The largest effects of micronutrient addition are evident in the first two days of both sterile and unfiltered fermentations.

A comparative study of chitin synthase activity in two Mortierella species

An in vitro investigation of some important factors controlling the activity of chitin synthase in cell-free extracts of two Mortierella species has been carried out. Mixed membrane fractions from mycelial homogenates of Mortierella candelabrum and Mortierella pusilla were found to catalyse the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine into an insoluble product characterized as chitin by its insolubility in weak acid and alkali, and the release of glucosamine and diacetylchitobiose on hydrolysis with a strong acid and chitinase, respectively. Apparent Km values for UDP-GlcNAc were 1.8 mM and 2.0 mM for M. pusilla and ~ candelabrum, respectively. Polyoxin D was found to be a very potent competitive inhibitor with values of the constant of inhibition, Ki' for both species about three orders of magnitude lower than theKm for UDP-GlcNAc. A divalent cation, Mg+2 , Mn+2 or Co+2 , was required for activity. N-acetylglucosamine, the monomer of chitin, stimulated the activity of the enzyme. The crude enzyme preparation of ~ candelabrum, unlike that of ~ pusilla, showed an absolute requirement for both Mg+2 and N-acetylglucosamine. Large differences in response to exogenous proteases were noted in the ratio of active to inactive chitin synthase of the two species. A fifteen fold or greater increase was obtained after treatment with acid protease (from Aspergillussaitoi) as compared to a two- to four-fold activation of the M. pusilla membrane preparation treated similarly. During storage at 4°C over 48 hours, an endogenous activation of chitin synthase of ~ pus ilIa was achieved, comparable to that obtained by exogenous protease treatment. The high speed supernatant of both species inhibited the chitin synthase activity of the mixed membrane fractions. The inhibitor of ~ pus ilIa was effective against the pre-activated enzyme whereas that of M. candelabrum inhibited the activated enzyme. Several possibilities are discussed as to the role of the different factors regulating the enzyme activity. The suggestion is made from the properties of chitin synthase in the two species that in vivo a delicate balance exists between the activation and inactivation of the enzyme which is responsible for the pattern of wall growth of each fungus.

Hydrogen sulphide as inhibitor and substrates for the cytochrome c-cytochrome c oxidase system /

It has previously been recognized that the major biochemical toxicity induced by sulphide is due to an inhibition of cytochrome ~ oxidase. Inhibition of this enzyme occurs at 30°C and pH 7.4 with a Ki of approximately 0.2 ~M, and a kon of 104 M-1 s-l, under catalytic conditions. However, the equimo1ar mixture of sulphide and the enzyme shows identical catalytic behaviour to that of the native enzyme. This cannot readily be attributed to rapid dissociation of sulphide, as both spectroscopic and plot analysis indicate the koff value is low. The addition of stoichiometric sulphide to the resting oxidized enzyme gives rise to the appearance of a low-spin ferric-type spectrum not identical with that seen on the addition of excess sulphide to the enzyme aerobically. Sulphide added to the enzyme anaerobically gives rise to another low-spin, probably largely ferric, form which upon admission of oxygen is then converted into a 607 nm species closely resembling Compound C. The 607 nm form is probably the precursor of oxyferricytochrome aa3. The addition of successive a1iquots of Na2S solution to the enzyme induces initial uptake of approximately 3 moles of oxygen per mole of the enzyme. Thus, it is concluded that: 1. the initial product of sulphide-cytochrome c oxidase interaction is not an inhibited form of the enzyme, but the low-spin (oxyferri) ~3+~+ species; 2. a subsequent step in which sulphide reduces cytochrome ~ occurs; 3. the final inhibitory step, in which a further molecule of sulphide binds to the cytochrome ~ iron centre in the cytochrome ~2+~+ species, gives the cytochrome a2+~+-H2S form which is a half-reduced fully inhibited species;4. a 607 run form of the enzyme is produced which may be converted into a catalytically active low-spin (oxyferri) state; and therefore 5. liganded sulphide may be able to reduce the cytochrome 33 -Cu centre without securing the prior reduction of the cytochrome a_ haem group or the Cud centre associated with it.

Study of new yeast strains as novel starter cultures for Riesling icewine production

Icewine is a sweet dessert wine fermented from the juice of grapes naturally frozen on the vine. The production of Icewine faces many challenges such as sluggish fermentation, which often yields wines with low ethanol, and an accumulation of high concentration of volatile acidity, mainly in the form of acetic acid. This project investigated three new yeast strains as novel starter cultures for Icewine fermentation with particular emphasis on reducing acetic acid production: a naturally occurring strain of S. bayanus/S. pastorianus isolated from Icewine grapes, and two hybrids between S. cerevisiae and S. bayanus, AWRI 1571 and AWRI 1572. These strains were evaluated for sugar consumption patterns and metabolic production of ethanol, glycerol and acetic acid, and were compared to the performance of a standard commercial wine yeast KI-VI116. The ITS rONA region of the two A WRI crosses was also analyzed during fermentations to assess their genomic stability. Icewine fermentations were performed in sterile filtered juice, in the absence of indigenous microflora, and also in unfiltered juice in order to mirror commercial wine making practices. The hybrid A WRI 1572 was found to be a promising candidate as a novel starter culture for Icewine production. I t produced 10.3 % v/v of ethanol in sterile Riesling Icewine fermentations and 11.2 % v/v in the unfiltered ones within a reasonable fermentation time (39 days). Its acetic acid production per gram sugar consumed was approximately 30% lower in comparison with commercial wine yeast K I -V 1116 under both sterile filtered and unfiltered fermentations. The natural isolate S. bayanus/S. pastorianus and AWRI 1571 did not appear to be suitable for commercial Icewine production. They reached the target ethanol concentration of approximately 10 % v/v in 39 day fermentations and also produced less acetic acid as a function of both time and sugar consumed in sterile fermentations compared to KI-V1116. However, in unfiltered fermentations, both of them failed to produce the target concentration of ethanol and accumulated high concentration of acetic acid. Both A WRI crosses displayed higher loss of or reduced copies in ITS rDNA region from the S. bayanus parent compared to the S. cerevisiae parent; however, these genomic losses could not be related to the metabolic profile.