Biometric Study of Acetoin Production in Hanseniaspora guilliermondii and Kloeckera apiculata

Gas chromatographic analysis by direct injection of samples yielded quantitative data on acetoin content. Ninety-six strains of Hanseniaspora guilliermondii and Kloeckera apiculata were investigated for the ability to produce acetoin in synthetic medium and in must. High-level production of acetoin was found to be a characteristic of both species. In synthetic medium, the two species were not significantly different with respect to sugar utilization and ethanol or acetoin production. In grape must, the two species were significantly different (P = 0.001) in acetoin production and K. apiculata exhibited a significantly negative correlation between acetoin production and either sugar consumption or ethanol production. Use of selected apiculate yeasts in mixed cultures with Saccharomyces cerevisiae seems promising for optimization of wine bouquet.     

Effects of UV-B radiation on photosynthetic reactions in Rhizophora apiculata

Influences of UV-B radiation on Rhizophora apiculata were studied in terms of chlorophylls, their presence in protein complexes of the chloroplast, PS I and PS II photochemical activities, in vitro absorption spectrum of the chloroplast, in vivo leaf fluorescence and UV absorbing compounds. The seedlings were exposed to the various levels of UV-B radiations, equivalent to 0 (control), 10, 20, 30 and 40% stratospheric ozone depletion of the study area. The low doses of UV-B (10 and 20%) increased the reaction centre chlorophyll (10 and 8%) and activities of PS-I (98 and 39%) and PS-II (77 and 38%) respectively; whereas, 30 and 40% UV-B treatments decreased the reaction centre chlorophylls by 11 and 33% and PS II activity by 0 and 20%; while PS I activity did not show any inhibitory effect. Chloroplasts isolated from control and 10% UV-B treated plants exhibited the same level of absorption at 676 nm. In vivo leaf fluorescence was found to be diminished with UV-B radiation and at the 10% UV-B, variable fluorescence was promoted significantly by 10%. The content of UV-absorbing compounds was progressively enhanced with doses of UV-B radiation along with higher absorption at 276 and 330 nm.     

Entwicklungsgeschichte der ChytridialeEntophlyctis apiculata auf der ProtococcaleHypnomonas lobata

Zusammenfassung Entophlyctis apiculata kommt auf einem bisher unbekannten Wirt, der ProtococcaleHypnomonas lobata, vor. Sie tritt, in Übereinstimmung mit früheren Angaben, bei tiefen Wassertemperaturen auf. Die Schädigung von Seiten des Parasiten setzt verhältnismäßig spät ein: die kontraktilen Vakuolen der befallenen Algenzellen schlagen lange Zeit weiter, obwohl sehr frühzeitig, d. h. ungefähr gleichzeitig mit der Anlage des Sporangiums, ein haustoriales Rhizoidensystem entsteht. Am Ende der Entwicklung ist der Algenprotoplast immer völlig zerstört.Die Entwicklung des Pilzes erfolgt grundsätzlich anders als bisher angegeben wurde: die persistierende Zoosporencyste nimmt nur wenig an der Bildung des Sporangiums teil und wird nicht zur Öffnungspapille. Diese entsteht neben dem von der Zoospore gebildeten Anhängsel. Der Apikulus der Autoren ist also nicht die Zoosporencyste. Es handelt sich somit um den gleichen Ablauf wie bei der operkulaten, sehr ähnlichen ParallelformEndochytrium pseudodistomum.Das Rhizoidensystem ist grundsätzlich immer gleich gebaut, variiert aber in der Stärke seiner Ausbildung beträchtlich.Die AngabenKorschikows für die seltene (oder nur oft verkannte?)Hypnomonus lobata werden bestätigt und in Einzelheiten ergänzt.Die oben alsHypnomonas lobata bezeichnete Art besitzt auch größte Ähnlichkeit mit der von O. A.Korschikow (1953, S. 60, Fig. 4) neu beschriebenenH.ellipsoidea aus der Ukraine: die kontraktilen Vakuolen liegen an den Breitseiten der Zellen, die erwachsenen Zellen sind meist oval.     

Flocculation and cell surface characterization of Kloeckera apiculata from wine

AIMS: To characterize and analyze the flocculation phenomenon of Kloeckera apiculata mc1 from Argentinian wine to understand the cell-cell interaction pattern. METHODS AND RESULTS: Kloeckera apiculata mc1 possess intense cell-cell interactions in MYPG medium (0.5% malt extract, 1% yeast extract, 2% glucose, 2% peptone), pH 5.5 by shaking at 25 degrees C. Optimum flocculation is observed at pH 4.5 in the presence of 3 mmol l-1 Ca2+. The flocculation is induced by peptone and malt extract and not by yeast extract and is reversed by 50 mmol l-1 galactose or lactose. The flocculation is highly susceptible to pronase, chymotrypsine and proteases types IV and XXVII and is partially resistant to trypsin. The electronic microscopy shows that the cells are attached to each other along their sides by fine hair-like threads. CONCLUSIONS: The mechanism of flocculation of K. apiculata mc1 is mediated by protein-carbohydrate interaction, stabilized by Ca2+. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of selected pure yeast inocula of known ability is preferred to wine elaboration, therefore the indigenous flora must be avoided and the flocculation of K. apiculata could be an economic method to do it.     

Isolation of Hanseniaspora uvarum (Kloeckera apiculata) in humans

Isolation of Hanseniaspora uvarum, a yeast of the ascomycetes group, whose anamorph corresponds to Kloeckera apiculata, obtained from stool and two ungual specimens from three patients, is reported. This yeast has been found in soil, water, various fruits, bivalve molluscs, crabs, prawns and fruit flies; in Spain, it has been described in the fermentation processes of some wines. In our region, it has also been found in the intestine of mackerel ( Scomber scombrus). Its finding in humans constitutes a clinical rarity. This revised version was published online in August 2006 with corrections to the Cover Date.     

The flocculation of wine yeasts: biochemical and morphological characteristics in Kloeckera apiculata

The floc-forming ability of flocculent strains of Kloeckera apiculata, isolated from musts, was tested for susceptibility to proteinase and sugar treatments. Three different flocculation phenotypes were discriminated by protease digestion, whereas the inhibition of flocculation by sugars distinguished two definite patterns: one mechanism of flocculation involved a galactose-specific protein and the other a broad-specificity lectin. SEM and TEM observation of the cell surface of two different Kloeckera strains revealed fine fibrils and a diffuse structure at the point of contact in one strain, and thick masses of mucus on the cell wall of the other strain.     

Typing of Saccharomyces cerevisiae and Kloeckera apiculata strains from Aglianico wine

AIMS: Kloeckera apiculata and Saccharomyces cerevisiae yeast species are dominant, respectively, at the early and at the following stages of wine fermentation. In the present study, PCR fingerprinting and NTS region amplification and restriction were applied as techniques for monitoring yeast population performing Aglianico of Vulture grape must fermentation. METHODS AND RESULTS: Thirty S. cerevisiae and 30 K. apiculata strains were typed by PCR fingerprinting with (GAC)5 and (GTG)5 primers and by complete NTS region amplification followed by restriction with HaeIII and MspI enzymes. S. cerevisiae strains generated two patterns with (GAC)5 primer, while (GTG)5 primer yielded a higher genetic polymorphism. Conversely, in K. apiculata Aglianico wine strains (GAC)5 and (GTG)5 primers generated the same profile for all strains. Restriction analysis of the amplified NTS region gave the same profile for all strains within the same species, except for one strain of S. cerevisiae. CONCLUSIONS: The PCR fingerprinting technique was useful in discriminating at strain level S. cerevisiae, particularly with the primer (GTG)5. RFLP patterns generated from the NTS region of the two species can be more easily compared than the patterns resulting from PCR fingerprinting, thus RFLP is more suitable for the rapid monitoring of the species involved in different stages of fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: The molecular techniques used allow discrimination of S. cerevisiae at strain level and monitoring of the ratio of S. cerevisiae/K. apiculata during the fermentation process. Thus, their application can assure technological adjustments in a suitable time.     

Genital morphology and fertilization success in the dung beetle Onthophagus taurus: an example of sexually selected male genitalia

In animals with internal fertilization and promiscuous mating, male genitalia show rapid and divergent evolution. Three hypotheses have been suggested to explain the evolutionary processes responsible for genital evolution: the lock-and-key hypothesis, the pleiotropy hypothesis and the sexual-selection hypothesis. Here, we determine whether variation in male genital morphology influences fertilization success in the dung beetle Onthophagus taurus, as predicted by the sexual-selection hypothesis. Variation in four out of five genital sclerites of the endophallus influenced a male's fertilization success, supporting the general hypothesis that male genitalia can evolve under sexual selection. Furthermore, different genital sclerites were found to enhance first versus second male paternity, indicating that different sclerites serve offensive and defensive roles. Genital-trait variability was comparable to that in other species but was less variable than a non-genital sexually selected trait (head horns). We suggest that directional selection for genital elaboration may be countered by natural selection, which should favour genitalia of a size and shape necessary for efficient coupling and sperm transfer.     

The effect of selected trace metals on the fertilization success of several scleractinian coral species

This study provides new information on the effects of various concentrations of the trace metals copper, lead, zinc, cadmium, and nickel on fertilization success of gametes from the scleractinian reef corals Goniastrea aspera,Goniastrea retiformis, Acropora tenuis, and Acropora longicyathus. The EC50 values (the concentration that reduces the fertilization rate by 50% relative to the control fertilization) for copper effects on fertilization success of these coral species range from 15 to 40 μg/L, which is similar to responses of other marine invertebrates. The EC50 values for lead were 1450–1800 μg/L for the Acropora species, and >2400 μg/L for G. aspera gametes, which indicates that lead was much less toxic than copper. Fertilization responses to zinc and nickel were variable and a significant reduction in fertilization success for A. tenuis gametes was found only at very high cadmium concentrations. The data from this study and other recent research clearly demonstrate that some trace metals impair the fertilization success of gametes from faviid and acroporiid reef corals. Trace metal inputs into reef waters should be limited and controlled to avoid potential interference with sexual reproductive processes of reef corals.     

Characterization of Kloeckera apiculata strains from the Friuli regionin Northern Italy

Forty-nine strains of Kloeckera apiculata, isolated from the Friuli region in Italy, were differentiated on the basis of fermentation behaviour and production of secondary compounds in two different grape musts at 18 °C. The isolates exhibited a controlled production of acetic acid, only in a few cases more that 1 g/l. In Moscato grape must the strains exhibited a more uniform behaviour for the production of higher alcohols, ethyl acetate and acetoin than in red grapes. In general, higher levels of ethanol, glycerol and acetic acid were produced in red grape must fermentation. Apiculate strains behaved differently in the two musts, with different metabolic phenotypes dominating the fermentation process. The existence of different metabolic phenotypes correlated with the must composition underlines the need to perform a selection of indigenous apiculate yeasts to obtain the desired consistent products.     

On the magnesium content in sea urchin eggs and its changes accompanying fertilization

Summary The content of total and bound magnesium of the eggs ofPseudocentrotus depressus andHemicentrotus pulcherrimus was estimated by atomic absorption spectrophotometry. The amount of total magnesium was almost equal (0.128 gmg/g PO₄) in both species and did not change upon fertilization. Bound magnesium decreased in fifteen minutes after fertilization and recovered the original value in further fifteen minutes. The role of magnesium in the fertilization process was discussed with the presence of the experimental results.     

Physiological variants of Saccharomyces cerevisiae and Kloeckera apiculata from palm wine and cashew juice

Physiological variants of Saccharomyces cerevisiae and Kloeckera apiculata have been identified in oil palm wine and cashew juice from Nigeria. Genomic DNA from the four S. cerevisiae variants had a % G + C of 36–41% while that of K. apiculata was 32.2%. Fermentation of cashew juice produced wine of alcoholic contents of 10% with S. cerevisiae , 8% with K. apiculata and 9.3% with both yeasts simultaneously. and accepted 31 August 1989     

Physiological variants of Saccharomyces cerevisiae and Kloeckera apiculata from palm wine and cashew juice

Physiological variants of Saccharomyces cerevisiae and Kloeckera apiculata have been identified in oil palm wine and cashew juice from Nigeria. Genomic DNA from the four S. cerevisiae variants had a % G + C of 36-41% while that of K. apiculata was 32.2%. Fermentation of cashew juice produced wine of alcoholic contents of 10% with S. cerevisiae, 8% with K. apiculata and 9.3% with both yeasts simultaneously.     

On the egg investments and fertilization reaction inPomatoceros triqueter L.

Summary After a specific time of glutaraldehyde-acrolein fixation, microtubule walls appear to be composed of single 6.5–7.5 nm diameter osmiophilic subunits. Variations in the duration of glutaraldehyde-acrolein and also glutaraldehyde-osmium fixation reveal a two layered wall containing osmiophilic subunits, 4.0–4.5 nm in diameter, arranged radially, in tandem. The double-layered wall is demonstrated by microdensitometer traces. These observations are discussed in relation to previously proposed models of microtubule substructure.     

Influence of ultraviolet-B radiation on photosynthetic and biochemical characteristics of a mangrove Rhizophora apiculata

Changes in photosynthesis and biochemical constituents were studied in R. apiculata seedlings grown under solar and solar enhanced UV-B radiation, equivalent to 10, 20, 30, and 40 % stratospheric ozone depletion. The seedlings grown under 10 % UV-B radiation showed an increase of 45 % net photosynthetic rate (PN) and 47 % stomatal conductance, while seedlings grown under 40 % UV-B radiation exhibited a decrease of 59 % PN with simultaneous elevation of 73 % intercellular CO2 concentration. Effects of UV-B on contents of lipids, saccharides, amino acids, and proteins were significant only at high doses of UV-B radiation. The concentration of anthocyanin was reduced with increasing doses of UV-B. The reverse was true with phenols and flavonoids.     

Relationship between ethanol tolerance, lipid composition and plasma membrane fluidity in Saccharomyces cerevisiae and Kloeckera apiculata

Abstract The lipid composition of a strain of each of two yeasts, Saccharomyces csrevisiae and Kloeckera apiculata , with different ethanol tolerances, was determined for cells grown with or without added ethanol. An increase in the proportion of ergosterol, unsaturated fatty acid levels and the maintenance of phospholipid biosynthesis seemed to be responsible for ethanol tolerance. The association of ethanol tolerance of yeast cells with plasma membrane fluidity, measured by fluorescence anisotropy, is discussed. We propose that an increase in plasma membrane fluidity may be correlated with a decrease in the sterol: phospholipid and sterol: protein ratios and an increase in unsaturation index.     

Carbohydrates and fertilization in animals

A frequently used mechanism for sperm-egg recognition in many species involves complementary protein-carbohydrate interaction. The usual paradigm includes complex glycoconjugates in reproductive tract fluids or on the eggs which are recognized by carbohydrate-binding proteins on the sperm surface. Various glycoconjugates are utilized in the steps of sperm capacitation, sperm binding to the egg extracellular matrix and vitelline membrane and induction of the acrosome reaction. Several types of complex glycoconjugates are involved in these processes, including proteoglycans, lactosaminoglycans, sulfated fucose-containing glycoconjugates, and glycoproteins. There appear to be some structural similarities between active glycoconjugates; they are large in molecular weight and complex, and they are often sulfated, fucosylated, and attached to a protein through serine or threonine residues. In some species, the protein core of the glycoconjugates also participates in the interaction by limiting the binding of carbohydrates to sperm only of the relevant species, likely by providing the proper steric arrangement for the interaction. In other cases the protein core seems to serve more as a crosslinker of the carbohydrate moieties. This review discusses the types of glycoconjugates implicated in fertilization and the complementary lectin-like proteins found on sperm.     

Archegonium and fertilization in Coniferopsida

Key message

This paper reviews studies on the origin and development of the Coniferopsida’s archegonium, illustrates the relationship between the archegonium and fertilization, and discusses the molecular regulation of archegonium development.

Abstract

This paper reviews studies on the origin and development of the Coniferopsida’s archegonium and discusses the characteristics of the archegonial cells and the molecular regulation of archegonium development. There are some main conclusions which could be drawn from this review. (1) It enables the precise position of the archegonium in the ovule to be determined as well as its structural features. (2) The functions of the neck cells in Coniferopsida are that they may serve as channels for sperms to enter the archegonia and lead the growth of pollen tubes. (3) The proteid vacuoles in egg cell may provide nutrition for fertilization and lead to the paternal inheritance of plastids in some Coniferopsida. (4) The uniparental transmission of plastids results from “the active digestion of male organelle nuclei (genomes) in young zygotes” in almost all Coniferopsida. (5) The studies on the molecular regulation of the archegonium and fertilization in Coniferopsida are still very limited and that is the direction for further research. In summary, the review provides a theoretical basis for further study on the developmental and reproductive biology of the Coniferopsida.