Effect of trace elements upon the biomass production of some candida species

Trace element studies were carried out on nine species of Candida. Out of twenty-three trace elements tested, Fe, Zn, Mn and Cu were found to be essential for the growth of all the yeast species whereas the rest of the elements exhibited variable essentiality. All the species of yeasts investigated required different concentrations of trace elements for their optimum growth. Concentrations higher than the optimum have been found to be inhibitory for the growth of all the yeasts studied here.     

Chemical Composition of Hydrodistilled Essential Oil of Artemisia incana (L.) Druce and Antimicrobial Activity against Foodborne Microorganisms

The oil obtained by hydrodistillation from the aerial parts of Artemisia incana (L.) Druce from Turkey was analyzed by GC and GC/MS. Sixty‐three compounds were characterized, representing 97.2% of the total components detected, and camphor (19.0%), borneol (18.9%), 1,8‐cineole (14.5%), bornyl acetate (7.8%), camphene (4.9%), and α‐thujone (4.8%) were identified as predominant components. The essential oil was also tested for its antimicrobial activity against 44 different foodborne microorganisms, including 26 bacteria, 15 fungi, and 3 yeast species. The essential oil of A. incana exhibited considerable inhibitory effects against all bacteria, fungi, and yeast species tested. However, the oil showed lower inhibitory activity against the tested bacteria than the reference antibiotics.     

Biogenesis of mitochondria 51

Summary An examination of the effect of the aminoglycoside antibiotics paromomycin and neomycin on mitochondrial ribosome function in yeast has been made. Both antibiotics are potent inhibitors of protein synthesis in isolated mitochondria. With isolated mitochondrial ribosomes programmed with polyuridylic acid (poly U), the drugs are shown to inhibit polyphenylalanine synthesis at moderately high concentrations (above 100 g/ml). At lower concentrations (about 10 g/ml), paromomycin and neomycin cause a 2–3 fold stimulation in the extent of misreading of the UUU codons in poly U, over and above the significant level of misreading catalyzed by the ribosomes in the absence of drugs.Comparative studies have been made between a paromomycin sensitive strain D585-11C and a mutant strain 4810P carrying the parl-r mutation in mtDNA, which leads tohigh resistance to both paromomycin and neomycin in vivo. A high level of resistance to these antibiotics is observed in strain 4810P at the level of mitochondrial protein synthesis in vitro. Whilst the degree of resistance of isolated mitochondrial ribosomes from strain 4810P judged by the inhibition of polyphenylalanine synthesis by paromomycin and neomycin is not extensive, studies on misreading of the poly U message promoted by these drugs demonstrate convincingly the altered properties of mitochondrial ribosomes from the mutant strain 4810P. These ribosomes show resistance to the stimulation of misreading of the codon UUU brought about by paromomycin and neomycin in wild-type mitochondrial ribosomes. Although strain 4810P was originally isolated as being resistant to paromomycin, in all the in vitro amino acid incorporation systems tested here, the 4810P mitochondrial ribosomes show a higher degree of resistance to neomycin than to paromomycin.It is concluded that the parl-r mutation in strain 4810P affects a component of the mitochondrial ribosome, possibly by altering the 15S rRNA or a protein of the small ribosomal subunit. The further elucidation of the functions in the ribosomes that are modified by the parl-r mutation was hampered by the inability of current preparations of yeast mitochondrial ribosomes to translate efficiently natural messenger RNAs from the several sources tested.     

Studies on proteins of animal ribosomes

Summary Ribosomes from different tissues and species of animals were tested by several different immunochemical methods. With antisera produced in rabbits by injection of intact ribosomes significant species differences in the antigenic properties of the ribosomes could be demonstrated whereas no tissue conditioned properties in the antigenic determinants were found. Abbreviations. RRL: ribosomes of rat liver; RBL: ribosomes of bovine liver; RBK: ribosomes of bovine kidney; anti-RRL: antiserum against RRL; anti-RBL: antiserum against RBL; anti-RBK: antiserum against RBK.     

Studies of ribosomal proteins of yeast species and their hybrids gel electrophoresis and immunochemical cross-reactions

Summary The cytoplasmic ribosomal proteins (r-proteins) of seventeen yeast species of the genera Saccharomyces and Kluyveromyces were analyzed by one-dimensional gradient polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The electrophoretic patterns of cytoplasmic r-proteins from different species display extensive differences in both the 40S and the 60S subunit. Relatedness of species suggested by r-protein patterns correlates well with that based on DNA/DNA homology (Bicknell and Douglas 1970). Immunochemical cross-reactions and antibiotic susceptibility tests were also used to compare different species.Analyses of r-proteins from two different interspecific hybrids showed that their ribosomes were hybrid, containing r-proteins from both parents. These findings are discussed in relation to the evolution of yeast species and the regulation of expression of r-proteins in cucaryotes.     

A Mammalian Cell Regulatory Agent,CeReS-18, Inhibits Yeast Cell Proliferation But Not Bacterial Replication

A cell regulatory sialoglycopeptide, CeReS-18, purified from intact bovine cerebral cortex cells, has exhibited the capability of reversibly inhibiting cellular DNA synthesis and the proliferation of a wide array of mammalian cells. In the present study, the effect of CeReS-18 on the proliferation of bacterial (Bacillus cereus and Escherichia coli) and yeast (Saccharomyces cerevisiae and Schizosaccharomyces pombe) cells was investigated. The results showed that replication and viability of the bacterial cells were not affected by CeReS-18 at any concentration tested, including 15-fold higher than that used for inhibiting mouse 3T3 cell proliferation. In contrast to bacterial cells, CeReS-18 was able to inhibit the replication of yeast cells, in a concentration-dependent, reversible manner, and the addition of calcium to the culture medium could abrogate the inhibitory effect of CeReS-18. A cytotoxic effect of CeReS-18 on both yeast cell species was observed when it was applied at higher concentrations. Received: 13 March 2002 / Accepted: 22 July 2002     

Antimicrobial activity of protoanemonin,a lactone from ranunculaceous plants

Protoanemonin, a component of Ranunculus bulbosus, was tested as an antifungal agent on selected strains of dermatophytes and yeasts. The minimum inhibitory concentrations ranged from 2.0 to 7.5×10^–4 M and the minimum lethal concentrations from 3.8×10^–4 M to >1.0×10^–3 M. The most sensitive dermatophyte tested was Epidermophyton floccosum, and the most sensitive yeast Rhodotorula glutinis. The effects of different culture media and of light on the sensitivity of Rhodotorula glutinis to protoanemonin were also tested. Structural analogies between protoanemonin and other cytotoxic unsaturated lactones, and the reversal by the amino acid cysteine of the antifungal action suggest a possible mechanism of action.     

Ribosomal proteins

Summary A comparison of the protein patterns of the 70S and 80S ribosomes from various plants, E. coli and yeast by disc-gel electrophoresis has shown the following relations: 1. There is a greater similarity between chloroplast ribosomes from various plants than between chloroplast and cytoplasmic ribosomes obtained from the same plant. 2. The protein patterns of the cytoplasmic ribosomes from bean, spinach and tobacco are more similar to each other than when compared to that of wheat germ. 3. At least one band is common to cytoplasmic ribosomes from all plants tested. 4. Only very few bands with identical mobilities are observed between chloroplast and E. coli ribosomes and between cytoplasmic plant and yeast ribosomes.     

GENETIC VARIATION IN CACTOPHILIC DROSOPHILA FOR OVIPOSITION ON NATURAL YEAST SUBSTRATES

Theory predicts that environmental heterogeneity in space or in time can maintain genetic polymorphism. Stable polymorphisms are expected to be more readily maintained if there are genotype specific habitat preferences. Genotype specific preferences for oviposition sites in Drosophila could be a major factor promoting habitat selection, and thus the maintenance of genetic variation. This hypothesis is being tested using the cactophilic species, D. buzzatii and D. aldrichi, where available evidence indicates a potential for such habitat selection, the habitats (oviposition sites) being yeast species found in the natural environment of these flies (cactus rots). Genetic variation for oviposition preferences was tested using isofemale lines—for D. buzzatii, a total of 60 lines from seven localities widely distributed through the species range in Australia, and for D. aldrichi, 21 lines from three of these localities. Females were given a choice of five yeast species as oviposition sites. Genetic variation for oviposition preferences on these natural substrates was demonstrated. There was significant variation among isofemale lines within populations in their patterns of preferences for oviposition on the five yeast species. However, analyses of preferences for each yeast species separately showed that the genetic variation for preferences relates to only three of the five species. Heritabilities of individual female preferences for these three species were low, ranging up to 9%. Little geographic differentiation was apparent among populations, most likely due to similar selection regimes within each population. Within populations, this kind of habitat selection could act to maintain polymorphisms, both at loci determining the habitat preferences and at other loci in linkage disequilibrium with them.     

Identification of pathogenic yeast species by polymerase chain reaction amplification of the RPS0 gene intron fragment

Aims: This work focuses on the development of a method for the identification of pathogenic yeast. With this aim, we target the nucleotide sequence of the RPS0 gene of pathogenic yeast species with specific PCR primers. PCR analysis was performed with both the genomic DNA, whole cells of clinical isolates of Candida species and clinical samples. Methods and Results: A single pairs of primers, deduced from the nucleotide sequence of the RPS0 gene from pathogenic yeast, were used in PCR analysis performed with both the genomic DNA and whole cells of clinical isolates of Candida species and clinical samples. The primers designed are highly specific for their respective species and produce amplicons of the expected sizes and fail to amplify any DNA fragment from the other species tested. The set of primers was tested successfully for the identification of yeast from colonies, blood cultures and clinical samples. These results indicate that genes containing intron sequences may be useful for designing species‐specific primers for the identification of fungal strains by PCR. The sensitivity of the method with genomic DNA was evaluated with decreasing DNA concentrations (200 ng to 1 pg) and different cell amounts (10⁷–10⁵ cells). Conclusion: The results obtained show that the amplification of RPS0 sequences may be suitable for the identification of pathogenic and other yeast species. Significance and Impact of the Study: Identification of Candida species using molecular approaches with high discriminatory power is important in determining adequate measures for the interruption of transmission of this yeast. The approach described in this work is based on standard technology, and it is specific, sensitive and does not involve complex and expensive equipment. Furthermore, the method developed in this work not only can be used in eight yeast species, but also provides the basis to design primers for other fungi species of clinical, industrial or environmental interest.     

Resistance to cadmium salts and metal absorption by different microbial species

The present study evaluates the inhibitory activity and the absorption of cadmium (Cd) salts by different microbial species, including Gram-positive (Staphylococcus aureus andS. epidermidis), Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium, andProteus mirabilis) bacteria and one yeast (Candida albicans). The metal absorption by growing cells was considered both in liquid and in solid medium. For one strain ofP. aeruginosa the presence of Cd deposits inside the cell was investigated by transmission electron microscopy. Generally, the Gram-negative species tested proved to be highly resistant to Cd ions and accumulated great amounts of Cd during growth. Two strains ofP. aeruginosa showed a high degree of resistance to Cd and were particularly efficient in removing the metal from solutions. The Gram-positive bacteria showed a heterogeneous behavior: anS. aureus strain susceptible to Cd absorbed, at low metal concentrations, higher amounts of metal than a Cd-resistant one. The metal absorption for Gram-negative species was dose dependent, while for the Cd-resistant staphylococci it reached a plateau. Our results suggest that microorganisms can represent a good model to study the interactions between heavy metals and living organisms.     

Organic Nutrients in the Media for Propagation of Cymbidium in vitro

Protocorms of Cymbidium (Orchidaceae) were grown on media containing different organic nutrients. Of the sugars tested sucrose was better than maltose, glucose and fructose, and sucrose had an optimum concentration of 3 to 4 %. D-Mannose was significantly less effective than the other sugars. The amino acid mixtures casamino acids (casein hydrolysate) and tryptone increased growth while yeast extract was inhibitory and malt extract without effect. Optimal concentrations were 2 to 3 g · l^-1 casamino acids and 3 to 4 g · l^-1 tryptone. It was to some extent possible to substitute the amino acid mixtures with a single amino acid (glutamine at 300 mg · l^-1). Arginine was inhibitory and asparagine was without any effect. Vitamins proved to be unnecessary although there was a tendency towards increased growth with nicotinic acid and meso-inositol. Purines and pyrimidines were added to the medium but with no effect. Liquid endosperm from coconuts (10 to 15%) increased growth while the liquid endosperm from Aesculus hippocastanum was inhibitory. On the basis of these results a revised medium is proposed for the in vitro propagation of Cymbidium.     

Comparative trace element and organic growth factor requirements of five hansenula species

A comparative response of specific trace elements and organic growth factors for the growth of five Hansenula species (H. anomala, H. beijerinckii, H. ciferrii, H. polymorpha and H. sydowiorum) has been studied. Out of twenty three trace elements tested, Fe, Zn, Mn and Cu were found to be essential for the growth of all yeast species studied here, whereas the rest of the elements exhibited variable essentiality. From fifteen organic growth factors tested, thiamine, biotin, pyridoxine and inositol are the most commonly required growth factors by the yeasts, whereas the rest of the organic growth factors showed variable essentiality. All species of yeasts investigated required different concentrations of trace elements and organic growth factors for their optimum growth. Concentrations higher than the optimum have been found to be inhibitory for the growth of all the yeasts studied.     

Species of Agave with antimicrobial activity against selected pathogenic bacteria and fungi

The in vitro antimicrobial activity against pathogenic bacteria, yeast, and molds were examined in extracts of the Agave species A. lecheguilla, A. picta, A. scabra and A. lophanta using an agar diffusion technique. The extracts of A. picta produced zones of inhibition of 9–13 mm for E. coli, L. monocytogenes, S. aureus, and V. cholerae, while B. cereus and Y. enterocolitica were not inhibited. The other Agave species did not show any detectable inhibitory activity against the bacteria tested; however, all four Agave sp. were inhibitory against all yeast and molds analyzed as evident by 9–20 mm zones of inhibition. The minimum microbicidal concentration (MMC) of the active extract ranged from 1.8 to 7.0 mg/ml for the sensitive bacteria, and 2.0–3.0 mg/ml for yeast. In the case of molds, the minimum inhibitory concentration (MIC) of the active extracts ranged from 3.0 to 6.0 mg/ml. Together, these data suggest that the Agave sp. analyzed are potential antimicrobial candidates with a broad range of activity.     

Heavy metal tolerance in marine strains of Yarrowia lipolytica

Heavy metal tolerance of two marine strains of Yarrowia lipolytica was tested on solid yeast extract peptone dextrose agar plates. Based on minimum inhibitory concentration esteems, it is inferred that the two strains of Y. lipolytica were tolerant to heavy metals such as Pb(II), Cr(III), Zn(II), Cu(II), As(V), and Ni(II) ions. The impact of various heavy metal concentrations on the growth kinetics of Y. lipolytica was likewise assessed. With increased heavy metal concentration, the specific growth rate was reduced with delayed doubling time. Furthermore, biofilm development of both yeasts on the glass surfaces and in microtitre plates was assessed in presence of different heavy metals. In microtitre plates, a short lag phase of biofilm formation was noticed without the addition of heavy metals in yeast nitrogen base liquid media. A lag phase was extended over increasing metal concentrations of media. Heavy metals like Cr(VI), Cd(II), and As(V) are contrastingly influenced on biofilms’ formation of microtitre plates. Other heavy metals did not much influence on biofilms development. Thus, biofilm formation is a strategy of Y. lipolytica under stress of heavy metals has significance in bioremediation process for recovery of heavy metals from contaminated environment.

     

Antimicrobial activity of fatty acids from fruits of Peucedanum cervaria and P. alsaticum

Plants of the genus Peucedanum have been used in traditional medicine for a long time to treat different diseases including infectious diseases. The hexane fruits extracts of Peucedanum cervaria and P. alsaticum were examined for antimicrobial activity and analyzed for their fatty acid content. Fatty acid composition of oils were analyzed by GC/FID in methyl ester form. Minimal inhibitory concentrations (MICs) of fatty acid fractions against twelve reference bacterial and yeast strains were performed by the twofold serial microdilution broth method. Fourteen fatty acids were identified. Oleic and linoleic acids were found to be dominant. The extracts from both plants examined exhibited inhibitory effects against Gram‐positive strains tested with different MIC values (0.25–2 mg/ml); however, extract from P. alsaticum possessed stronger antibacterial properties and a broader spectrum. The growth of Gram‐negative bacteria and Candida spp. strains was not inhibited even at the highest extract concentration used (MIC>4 mg/ml). Standard fatty acids exhibited inhibitory effects towards all bacterial and yeast strains used in this study; however, the majority of bacteria were more sensitive to linoleic than to oleic acid. These results revealed, for the first time, that hexane extracts obtained from fruits of P. alsaticum and P. cervaria possess moderate in vitro antibacterial activity against Gram‐positive bacteria including staphylococci. Linoleic and oleic acids appear to be the compounds responsible for this effect, and a synergistic antimicrobial effect between these two fatty acids was indicated.     

Toxic and mutagenic effects of carcinogens on the mitochondria of Saccharomyces cerevisiae.

Summary Nineteen haploid yeast (Saccharomyces cerevisiae) strains were used to assess the relative growth inhibitory potencies on fermentable vs. non-fermentable media of a collection of carcinogenic and noncarcinogenic chemicals. The majority of carcinogens were distinctly more potent on the non-fermentable (glycerol) medium, where mitochondrial function is required for growth, than on the fermentable medium, where it is not. The anti-mitochondrial selectivity indicated by these growth tests was much slighter for the non-carcinogens. Similarly most carcinogens induced the cytoplasmic petite mutation whereas the non-carcinogens did not.Five carcinogens which were tested impaired the development of cytochromes aa ₃ and b in glucose cultures.Six carcinogens, when tested, inhibited growth on three fermentable sugars, the utilisation of which requires mitochondrial function.Out of five carcinogens which were examined, four suppressed the surface-dependent phenomenon of flocculence in a flocculating strain of yeast, at concentrations primarily affecting the mitochondrial system; the fifth had a similar but less pronounced effect.     

Chemical Diversity and Antimicrobial Activity of Salvia multicaulis Vahl Essential Oils

The chemical compositions and antimicrobial activities of the essential oils (EOs) of aerial parts of Salvia multicaulis Vahl , collected during the same week from two different Lebanese regions, were investigated. The EOs were obtained by hydrodistillation using a Clevenger‐type apparatus and characterized by GC and GC/MS analyses. The minimum inhibitory concentrations of these EOs were determined against one Gram‐negative and two Gram‐positive bacteria, one yeast, and five dermatophytes using the broth microdilution technique. One EO was notably active against Staphylococcus aureus, methicillin‐resistant S. aureus, and all of the Trichophyton species tested. Nerolidol was found to be the major compound in the active oil; nerolidol was also absent from the inactive oil. This study demonstrated that nerolidol shows antimicrobial activity and therefore significantly contributes to the antimicrobial potential of the oil. The chemical diversity of worldwide S. multicaulis EOs was analyzed, revealing that the EOs of this study belong to two different chemotypes found in the literature. The nerolidol chemotype appears to be restricted to Lebanon, and it can be used as antimicrobial agent against external bacterial and fungal infections.     

Recessive nonsense-suppression in yeast Saccharomyces cerevisiae

Summary The shift of recessive suppressor mutant of yeast Saccharomyces cerevisiae from permissive to restrictive conditions is accompanied by polysome decay and accumulation of 80 S ribosomes (Smirnov et al., 1976). In this paper some properties of 80 S ribosomes are studied. It is demonstrated that polysome decay under non-permissive conditions is not the consequence of the impairement of RNA synthesis. More than 70% of 80 S ribosomes accumulated under non-permissive conditions contain bound peptidyl-tRNAs localized in P-ribosomal site. tRNA moiety of bound peptidyl-tRNA is able to accept all 20 natural amino acids after chemical deacylation. Therefore it is not a specific isoacceptor species but rather total tRNA that is bound to ribosomes. The polypeptide residues of these peptidyl-tRNAs are heterogeneous in size. Their molecular weights are comparable with the molecular weights of the completed polypeptides. Some of the 80 S ribosomes accumulated under non-permissive conditions contain poly-A RNA. In conclusion, possible mechanism of the impairement of translation under non-permissive conditions in recessive suppressor strain is discussed.     

羊卓雍措水体可培养酵母菌多样性及其与理化因子相关性

【目的】开展羊卓雍措水体可培养酵母菌多样性研究,探究影响其多样性的主要理化因子。【方法】采用膜过滤平置培养法分离纯化酵母菌,并结合rRNA ITS区域序列分析与经典分类法对酵母菌菌株进行鉴定。运用SPSS 20.0和CANOCO 5分析可培养酵母菌多样性及其与理化因子之间的关系。【结果】羊卓雍措水体可培养酵母菌为16个属25个种,优势属为Vishniacozyma,优势物种为Vishniacozyma victoriae。Pearson相关系数显示,pH、电导率、总溶解固体量、盐度与各样点可培养酵母菌种数和属数呈显著正相关;总磷与各样点及各区域可培养酵母菌属数呈显著负相关,与各样点种数呈显著负相关。冗余分析显示,pH和总磷是影响羊卓雍措水体可培养酵母菌分布的主要环境因子。【结论】羊卓雍措水体酵母菌资源比较丰富且存在明显的空间异质性,人类活动对酵母菌分布有较大影响。酵母菌分布与人类活动的关系值得进一步研究。