Sistema “killer” en cepas de candida albicans. Parte I.

Se analizaron 94 ( 100%) cepas de levaduras de nuestra Micoteca pertenecientes principalmente a los géneros: Candida 64.89%; Saccharomyces 14%; Rhodotorula 5,31% y Pichia 4,25%. De todas las cepas estudiadas C. catenulata resultó killer positiva frente a cepas de C. alblcans sensibles, y también mostraron eficacia “killer” algunas cepas de C. albicans, C. guilliermondii, C. parapsilosis, C.pulcherrima, Hansenula anomala, C. utilis y Trigonopsis variabllis, con diferentes porcentajes de actividad.El objeto de esta comunicación es presentar los resultados de la búsqueda de un sistema "killer" adecuado que será posteriormente enfrentado a C. albicans y otras especies de este género aisladas de materiales clínicos que se procesan en nuestro laboratorio asistencial

Challenges of the Non-Conventional Yeast Wickerhamomyces anomalus in Winemaking

Nowadays it is widely accepted that non-Saccharomyces yeasts, which prevail during the early stages of alcoholic fermentation, contribute significantly to the character and quality of the final wine. Among these yeasts, Wickerhamomyces anomalus (formerly Pichia anomala, Hansenula anomala, Candida pelliculosa) has gained considerable importance for the wine industry since it exhibits interesting and potentially exploitable physiological and metabolic characteristics, although its growth along fermentation can still be seen as an uncontrollable risk. This species is widespread in nature and has been isolated from different environments including grapes and wines. Its use together with Saccharomyces cerevisiae in mixed culture fermentations has been proposed to increase wine particular characteristics. Here, we review the ability of W. anomalus to produce enzymes and metabolites of oenological relevance and we discuss its potential as a biocontrol agent in winemaking. Finally, biotechnological applications of W. anomalus beyond wine fermentation are briefly described.

Antimicrobial effect of an aqueous extract of Potentilla erecta rhizome

Potentilla erecta is a therapeutic plant used in folk medicine to treat inflammatory states, wounds and diseases of the alimentary tract. The results of the study reveal the effects of an aqueous extract of P. erecta rhizome on certain microorganisms occurring in food. The main components of the extract were catechins. The extract was shown to display an inhibiting effect against Gram-positive bacteria such as Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633, as well as against yeast such as Candida lipolitica KKP 322 and Hansenula anomala R 26. The extract did inhibit the growth of Gram-negative bacteria, however, no inhibiting effects were observed on moulds in the studied range of concentrations, i.e. 0.13 to 64 mg dry matter/ml.

Antioxidant and Antimicrobial Activities of Essential Oil and Extracts of Saurauia lantsangensis Hu Root

Antioxidant and antimicrobial activities of the essential oil and n-hexane (HEE), chloroform (CHE), ethyl acetate (EAE), and methanol (MEE) extracts, respectively, from the root of Saurauia lantsangensis Hu were investigated. The GC-MS analysis revealed 39 compounds representing 96.41% of the oil containing T-muurolol (13.85%), acetophenone (7.46%), α-cadinol (6.26%), methyl palmitate (5.36%), n-hexadecanoic acid (4.31%), torreyol (3.69%), and isospathulenol (3.48%) as major components. Antioxidant activities determined by three various testing systems, i. e. DPPH radical scavenging, superoxide anion radical scavenging, and reducing power assay, increased in the order: HEE < CHE < oil < MEE < EAE. CHE, EAE, MEE and oil exhibited a promising antimicrobial effect determined as the diameter of zones of inhibition (13.3 - 16.2, 16.5 - 20.4, 13.5 - 16.6, and 16.5 - 22.7 mm), respectively, along with their respective MIC values (500 - 1000, 125 - 500, 250 - 500, and 250 - 500 μg/ml) against Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli), Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus), and a yeast (Hansenula anomala).

Comparison of the Amino Acid Sequence of L–Mandelate Dehydrogenase From Rhodotorula Graminis With Other L–2–Hydroxyacid Dehydrogenase Enzyme and its Primary Structure Prediction

Perbandingan struktur primer L(+)–mendalate dehydrogenase (L–MDH) daripada yis Rhodotorula graminis dengan protein lain di dalam bank data protein menunjukkan persamaan di antara protein ini dengan kumpulan enzim L–2–hidroksiasid dehidrogenase. LMDH daripada R. graminis mempamerkan kesamaan antara 26–42% kepada L–lactate dehidrogenase daripada Sacchomoryces cerevisiae, L–lactate dehidrogenase daripada Hansenula anomala, glikolat oksida daripada bayam, L–laktat dehidrogenase daripada Escherichia coli, LMDH daripada Psedomonas putida dan laktat–2 monooksigenase daripada Mycobakterium smegmatis. Asid amino yang penting secara strukturnya bagi LMDH diramalkan secara perbandingan dengan bahagian penting domain sitokram dan domain perlekatan FMN yang diperoleh daripada struktur tiga dimensi L–laktat dehidrogenase daripada Sacchoromyces cerevisiae. Kata kunci: L-MDH; Rhodotorula gramisis; L(+)-mandalate dehydrogenase; asid amino,flavocytochrome b2 A comparison of the primary structure or L–mandelate dehydrogenase (L–MDH) from Rhodotorula graminis with other proteins from the protein databank suggests that there is similarity between this protein and L–2–hydroxyacid dehydrogenase enzymes. R graminis LMDH exhibits 26–42% identity to L–lactate dehydrogenase from Saccharomyces cerevisiae, L–lactate dehydrogenase from Hansenula anomala, glycolate oxidase from spinach, L–lactate dehydrogenase from Escherichia coli, L–mandelate dehydrogenase from Pseudomonas putida and lactate–2–monooxygenase from Mycobacterium smegmatis. Structurally conserved amino acids are predicted from LMDH sequences corresponding to important regions of the cytochrome and FMN–binding domain defined from the known three–dimensional structure of the L–lactate dehyrogenase from Sacchoromyces cerevisiae. Key words: L-MDH; Rhodotorula graminis; L-mandelate dehydrogenase; amino acid;flavocytochrome b2

Growth Inhibition of Various Enterobacteriaceae Species by the Yeast Hansenula anomala during Storage of Moist Cereal Grain

ABSTRACTEleven of 13Enterobacteriaceaespecies tested grew in moist stored wheat, highlighting a potential risk of this energy-saving airtight storage method. WhenHansenula anomalawas coinoculated, allEnterobacteriaceaespecies were significantly inhibited after 2 months of storage, six of them to below the detection limit.

Effect of the Combined Probiotics on Inhibiting Pathogenic Escherichia coli Prolification

The study on the combined probiotics to replace antibiotics becomes more and more important because the by-effects and appearance of “superbug” from abuse of antibiotics in human life and animal production. In order to get the effective combined probiotics for replacing antibiotics and inhibiting pathogenicEscherichia coli(E. coli) prolification, 3 strains ofBacillus subtilis(B. subtilis, named as B1, B2 and B3) were used to determine the pre-combination with experimental design (3 factors×4 levels), and then the pre-combination ofB. subtiliswas combined withLactobacillus casei(L. casei) andHansenula anomala(H. anomala) to achieve the most effective combined probiotics with the same design. The results indicated that the pre-combination ratio of B1, B2 and B3 was 0:1:1, and the most effective combination ratios of the pre-combination,L. caseiandH. anomalawere 0:1:1, 1:3:0, 2:2:3, 2:3:2, respectively (P<0.05). In addition, the incubating groups containingL. caseihad better effect on inhibitingE. coliprolification than those withoutLactobacillus, indicating thatLactobacillushad the best effect on inhibitingE. coliprolification, compared with other bacteria.