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1

Characterization of the cellular antigens of Paracoccidioides brasiliensis yeast form.  

PubMed Central

Antigenic components of the yeast extract of Paracoccidioides brasiliensis Linder 2511 cultured for 3, 8, 20, 30, and 60 days were examined by the Western blot (immunoblot) technique. The 3-day extract was chosen for characterization of the antigenic components because its stability did not vary with time and it contained all antigens identified by patient sera. Antibodies to cross-reacting antigens of P. brasiliensis extracts were detected in sera from patients with histoplasmosis, candidiasis, and aspergillosis. The 58-, 57-, 21-, and 16-kilodalton (kDa) antigens were specific for P. brasiliensis, while the 48- and 45-kDa antigens were specific for paracoccidioidomycosis. The Western blot technique is a useful tool for the diagnosis of disease and revealed heterogeneity in the responses of patient sera. The combination of the 58-, 57-, and 45-kDa proteins confirmed a diagnosis of paracoccidioidomycosis (87% of the cases). Images

Casotto, M

1990-01-01

2

Transcriptome Analysis of Paracoccidioides brasiliensis Cells Undergoing Mycelium-to-Yeast Transition  

Microsoft Academic Search

Paracoccidioides brasiliensis is a thermodimorphic fungus associated with paracoccidioidomycosis (PCM), a systemic mycosis prevalent in South America. In humans, infection starts by inhalation of fungal propagules, which reach the pulmonary epithelium and transform into the yeast parasitic form. Thus, the mycelium-to- yeast transition is of particular interest because conversion to yeast is essential for infection. We have used a P.

Luiz R. Nunes; Regina Costa de Oliveira; Daniela Batista Leite; Vivian Schmidt da Silva; E. dos Reis Marques; M. E. da Silva Ferreira; D. C. D. Ribeiro; L. A. de Souza Bernardes; M. H. S. Goldman; R. Puccia; L. R. Travassos; W. L. Batista; M. P. Nobrega; F. G. Nobrega; D.-Y. Yang; C. A. de Braganca Pereira; G. H. Goldman

2005-01-01

3

Preparation of species-specific murine monoclonal antibodies against the yeast phase of Paracoccidioides brasiliensis.  

PubMed Central

A panel of four murine monoclonal antibodies showing species specificity for the yeast phase of the pathogenic dimorphic fungus Paracoccidioides brasiliensis was produced by using a modification of the standard monoclonal antibody technology. This involved the use of the immunosuppressive drug cyclophosphamide to suppress the immune response of test animals to fungi showing cross-reactivity, i.e., to Histoplasma capsulatum. One monoclonal antibody, P4, which had a high titer by enzyme-linked immunosorbent assay, was shown to recognize a linear antigenic epitope of P. brasiliensis at a molecular size of 70,000 to 75,000 daltons by Western blot (immunoblot) analysis. The potential use of these monoclonal antibodies, which are the first species-specific probes to P. brasiliensis that have been produced, in the field of serodiagnosis is discussed. Images

Figueroa, J I; Hamilton, A J; Bartholomew, M A; Harada, T; Fenelon, L; Hay, R J

1990-01-01

4

In vitro effects of natural killer cells against Paracoccidioides brasiliensis yeast phase.  

PubMed Central

Recently, data have been reported suggesting natural killer (NK) cells may function in natural resistance against a fungus, Cryptococcus neoformans. The primary objective of this study was to examine the reactivity of murine splenic cells against another fungus, Paracoccidioides brasiliensis. Levels of NK activity in effector cell pools were varied by: (i) removing nylon wool-adherent cells, (ii) fractionating splenic cells on Percoll discontinuous gradients, (iii) using old and young effector cell donor mice, (iv) using donors from different strains, and (v) pretreating donors with NK-augmenting and -depressing agents. The various effector cell pools were simultaneously used in the 4-h 51Cr release assay with YAC-1 targets to determine the NK reactivity and in the in vitro growth inhibition assay against P. brasiliensis yeast phase targets. In each case, the level of NK reactivity correlated with the ability of the effector cells to inhibit the in vitro growth of P. brasiliensis. NK activity and P. brasiliensis growth-inhibiting ability could be augmented by fractionation of splenic cells through nylon wool or Percoll gradients. The effector cells responsible for the NK activity and P. brasiliensis growth inhibition were characterized as being nylon wool nonadherent, being found in the low-density fractions from Percoll discontinuous gradients, and having no detectable Thy-1 antigen or immunoglobulin but having asialo GM1 on their surface. These data support the contention that NK or NK-like cells are responsible for limiting the in vitro growth of P. brasiliensis.

Jimenez, B E; Murphy, J W

1984-01-01

5

Gene expression analysis of Paracoccidioides brasiliensis transition from conidium to yeast cell.  

PubMed

Paracoccidioides brasiliensis infectious process relies on the initial expression of virulence factors that are assumed to be controlled by molecular mechanisms through which the conidia and/or mycelial fragments convert to yeast cells. In order to analyze the profile of the thermally-induced dimorphic gene expression, 48 h C-L transition cultures which had been incubated at 36 degrees C were studied. By this time approximately 50% of the conidial population had already reverted to yeast form cells. At this transition time, an EST-Orestes library was constructed and characterized. As a result, 79 sequences were obtained, of which 39 (49.4%) had not been described previously in other libraries of this fungus and which could represent novel exclusive C-Y transition genes. Two of these sequences are, among others, cholestanol delta-isomerase, and electron transfer flavoprotein-ubiquinoneoxidoreductase (ETF-QO). The other 40/79 (50.6%) sequences were shared with Mycelia (M), Yeast (Y) or Mycelia to yest transition (M-Y) libraries. An important component of this group of sequences is a putative response regulator receiver SKN7, a protein of high importance in stress adaptation and a regulator of virulence in some bacteria and fungi. This is the first report identifying genes expressed during the C-Y transition process, the initial step required to understand the natural history of P. brasiliensis conidia induced infection. PMID:19568977

García, Ana M; Hernández, Orville; Aristizabal, Beatriz H; De Souza Bernardes, Luciano A; Puccia, Rosana; Naranjo, Tony W; Goldman, Gustavo H; Goldman, Maria H; Cano, Luz E; Restrepo, Angela; McEwen, Juan G

2010-02-01

6

Transcriptome analysis of Paracoccidioides brasiliensis cells undergoing mycelium-to-yeast transition.  

PubMed

Paracoccidioides brasiliensis is a thermodimorphic fungus associated with paracoccidioidomycosis (PCM), a systemic mycosis prevalent in South America. In humans, infection starts by inhalation of fungal propagules, which reach the pulmonary epithelium and transform into the yeast parasitic form. Thus, the mycelium-to-yeast transition is of particular interest because conversion to yeast is essential for infection. We have used a P. brasiliensis biochip carrying sequences of 4,692 genes from this fungus to monitor gene expression at several time points of the mycelium-to-yeast morphological shift (from 5 to 120 h). The results revealed a total of 2,583 genes that displayed statistically significant modulation in at least one experimental time point. Among the identified gene homologues, some encoded enzymes involved in amino acid catabolism, signal transduction, protein synthesis, cell wall metabolism, genome structure, oxidative stress response, growth control, and development. The expression pattern of 20 genes was independently verified by real-time reverse transcription-PCR, revealing a high degree of correlation between the data obtained with the two methodologies. One gene, encoding 4-hydroxyl-phenyl pyruvate dioxygenase (4-HPPD), was highly overexpressed during the mycelium-to-yeast differentiation, and the use of NTBC [2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione], a specific inhibitor of 4-HPPD activity, as well as that of NTBC derivatives, was able to inhibit growth and differentiation of the pathogenic yeast phase of the fungus in vitro. These data set the stage for further studies involving NTBC and its derivatives as new chemotherapeutic agents against PCM and confirm the potential of array-based approaches to identify new targets for the development of alternative treatments against pathogenic microorganisms. PMID:16339729

Nunes, Luiz R; Costa de Oliveira, Regina; Leite, Daniela Batista; da Silva, Vivian Schmidt; dos Reis Marques, Everaldo; da Silva Ferreira, Márcia Eliana; Ribeiro, Diógenes Custódio Duarte; de Souza Bernardes, Luciano Angelo; Goldman, Maria Helena S; Puccia, Rosana; Travassos, Luiz R; Batista, Wagner L; Nóbrega, Marina Pasetto; Nobrega, Francisco G; Yang, Ding-Yah; de Bragança Pereira, Carlos A; Goldman, Gustavo H

2005-12-01

7

Transcriptome Analysis of Paracoccidioides brasiliensis Cells Undergoing Mycelium-to-Yeast Transition  

PubMed Central

Paracoccidioides brasiliensis is a thermodimorphic fungus associated with paracoccidioidomycosis (PCM), a systemic mycosis prevalent in South America. In humans, infection starts by inhalation of fungal propagules, which reach the pulmonary epithelium and transform into the yeast parasitic form. Thus, the mycelium-to-yeast transition is of particular interest because conversion to yeast is essential for infection. We have used a P. brasiliensis biochip carrying sequences of 4,692 genes from this fungus to monitor gene expression at several time points of the mycelium-to-yeast morphological shift (from 5 to 120 h). The results revealed a total of 2,583 genes that displayed statistically significant modulation in at least one experimental time point. Among the identified gene homologues, some encoded enzymes involved in amino acid catabolism, signal transduction, protein synthesis, cell wall metabolism, genome structure, oxidative stress response, growth control, and development. The expression pattern of 20 genes was independently verified by real-time reverse transcription-PCR, revealing a high degree of correlation between the data obtained with the two methodologies. One gene, encoding 4-hydroxyl-phenyl pyruvate dioxygenase (4-HPPD), was highly overexpressed during the mycelium-to-yeast differentiation, and the use of NTBC [2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione], a specific inhibitor of 4-HPPD activity, as well as that of NTBC derivatives, was able to inhibit growth and differentiation of the pathogenic yeast phase of the fungus in vitro. These data set the stage for further studies involving NTBC and its derivatives as new chemotherapeutic agents against PCM and confirm the potential of array-based approaches to identify new targets for the development of alternative treatments against pathogenic microorganisms.

Nunes, Luiz R.; Costa de Oliveira, Regina; Leite, Daniela Batista; da Silva, Vivian Schmidt; dos Reis Marques, Everaldo; da Silva Ferreira, Marcia Eliana; Ribeiro, Diogenes Custodio Duarte; de Souza Bernardes, Luciano Angelo; Goldman, Maria Helena S.; Puccia, Rosana; Travassos, Luiz R.; Batista, Wagner L.; Nobrega, Marina Pasetto; Nobrega, Francisco G.; Yang, Ding-Yah; de Braganca Pereira, Carlos A.; Goldman, Gustavo H.

2005-01-01

8

Virulence insights from the Paracoccidioides brasiliensis transcriptome  

Microsoft Academic Search

Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is a dimorphic fungus, which is found as myce- lia at 22-26°C and as yeasts at 37°C. A remarkable feature common to several pathogenic fungi is their ability to differentiate from mycelium to yeast morphologies, or vice-versa. Although P. brasiliensis is a recog- nized pathogen for humans, little is known about its virulence

Aldo Henrique Tavares; Simoneide Souza Silva; Vanilce Vilmar Bernardes; Andréa Queiróz Maranhão; Cynthia Maria Kyaw; Marcio Poças-Fonseca; Ildinete Silva-Pereira

2005-01-01

9

Comparison of transcription of multiple genes during mycelia transition to yeast cells of Paracoccidioides brasiliensis reveals insights to fungal differentiation and pathogenesis  

Microsoft Academic Search

The ascomycete Paracoccidioides brasiliensis is a human pathogen with a broad distribution in Latin America. The infection process of P. brasiliensis is initiated by aerially dispersed mycelia propagules, which differentiate into the yeast parasitic phase in human lungs.\\u000a Therefore, the transition to yeast is an initial and fundamental step in the infective process. In order to identify and characterize\\u000a genes

Juliana Alves Parente; Clayton Luiz Borges; Alexandre Melo Bailão; Maria Sueli S. Felipe; Maristela Pereira; Célia Maria de Almeida Soares

2008-01-01

10

Paracoccidioides brasiliensis enolase is a surface protein that binds plasminogen and mediates interaction of yeast forms with host cells.  

PubMed

Paracoccidioidomycosis (PCM), caused by the dimorphic fungus Paracoccidioides brasiliensis, is a disseminated, systemic disorder that involves the lungs and other organs. The ability of the pathogen to interact with host components, including extracellular matrix (ECM) proteins, is essential to further colonization, invasion, and growth. Previously, enolase (EC 4.2.1.11) was characterized as a fibronectin binding protein in P. brasiliensis. Interaction of surface-bound enolase with plasminogen has been incriminated in tissue invasion for pathogenesis in several pathogens. In this paper, enolase was expressed in Escherichia coli as a recombinant glutathione S-transferase (GST) fusion protein (recombinant P. brasiliensis enolase [rPbEno]). The P. brasiliensis native enolase (PbEno) was detected at the fungus surface and cytoplasm by immunofluorescence with an anti-rPbEno antibody. Immobilized purified rPbEno bound plasminogen in a specific, concentration-dependent fashion. Both native enolase and rPbEno activated conversion of plasminogen to plasmin through tissue plasminogen activator. The association between PbEno and plasminogen was lysine dependent. In competition experiments, purified rPbEno, in its soluble form, inhibited plasminogen binding to fixed P. brasiliensis, suggesting that this interaction required surface-localized PbEno. Plasminogen-coated P. brasiliensis yeast cells were capable of degrading purified fibronectin, providing in vitro evidence for the generation of active plasmin on the fungus surface. Exposure of epithelial cells and phagocytes to enolase was associated with an increased expression of surface sites of adhesion. In fact, the association of P. brasiliensis with epithelial cells and phagocytes was increased in the presence of rPbEno. The expression of PbEno was upregulated in yeast cells derived from mouse-infected tissues. These data indicate that surface-associated PbEno may contribute to the pathogenesis of P. brasiliensis. PMID:20605975

Nogueira, Sarah Veloso; Fonseca, Fernanda L; Rodrigues, Marcio L; Mundodi, Vasanth; Abi-Chacra, Erika A; Winters, Michael S; Alderete, John F; de Almeida Soares, Célia Maria

2010-09-01

11

Paracoccidioides brasiliensis Enolase Is a Surface Protein That Binds Plasminogen and Mediates Interaction of Yeast Forms with Host Cells ?  

PubMed Central

Paracoccidioidomycosis (PCM), caused by the dimorphic fungus Paracoccidioides brasiliensis, is a disseminated, systemic disorder that involves the lungs and other organs. The ability of the pathogen to interact with host components, including extracellular matrix (ECM) proteins, is essential to further colonization, invasion, and growth. Previously, enolase (EC 4.2.1.11) was characterized as a fibronectin binding protein in P. brasiliensis. Interaction of surface-bound enolase with plasminogen has been incriminated in tissue invasion for pathogenesis in several pathogens. In this paper, enolase was expressed in Escherichia coli as a recombinant glutathione S-transferase (GST) fusion protein (recombinant P. brasiliensis enolase [rPbEno]). The P. brasiliensis native enolase (PbEno) was detected at the fungus surface and cytoplasm by immunofluorescence with an anti-rPbEno antibody. Immobilized purified rPbEno bound plasminogen in a specific, concentration-dependent fashion. Both native enolase and rPbEno activated conversion of plasminogen to plasmin through tissue plasminogen activator. The association between PbEno and plasminogen was lysine dependent. In competition experiments, purified rPbEno, in its soluble form, inhibited plasminogen binding to fixed P. brasiliensis, suggesting that this interaction required surface-localized PbEno. Plasminogen-coated P. brasiliensis yeast cells were capable of degrading purified fibronectin, providing in vitro evidence for the generation of active plasmin on the fungus surface. Exposure of epithelial cells and phagocytes to enolase was associated with an increased expression of surface sites of adhesion. In fact, the association of P. brasiliensis with epithelial cells and phagocytes was increased in the presence of rPbEno. The expression of PbEno was upregulated in yeast cells derived from mouse-infected tissues. These data indicate that surface-associated PbEno may contribute to the pathogenesis of P. brasiliensis.

Nogueira, Sarah Veloso; Fonseca, Fernanda L.; Rodrigues, Marcio L.; Mundodi, Vasanth; Abi-Chacra, Erika A.; Winters, Michael S.; Alderete, John F.; Soares, Celia Maria de Almeida

2010-01-01

12

Identification of genes preferentially expressed in the pathogenic yeast phase of Paracoccidioides brasiliensis , using suppression subtraction hybridization and differential macroarray analysis  

Microsoft Academic Search

Paracoccidioides brasiliensis, a thermodimorphic fungus, is the causative agent of paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in Latin America. Pathogenicity appears to be intimately related to the dimorphic transition from the hyphal to the yeast form, which is induced by a shift from environmental temperature to the temperature of the mammalian host. Little information is available on the P.

E. R. Marques; M. E. S. Ferreira; R. D. Drummond; J. M. Felix; M. Menossi; M. Savoldi; L. R. Travassos; R. Puccia; W. L. Batista; K. C. Carvalho; M. H. S. Goldman; G. H. Goldman

2004-01-01

13

Evidence for the Role of Calcineurin in Morphogenesis and Calcium Homeostasis during Mycelium-to-Yeast Dimorphism of Paracoccidioides brasiliensis?  

PubMed Central

Paracoccidioides brasiliensis is a dimorphic fungus that causes paracoccidioidomycosis, the most prevalent human deep mycosis in Latin America. The dimorphic transition from mycelium to yeast (M-Y) is triggered by a temperature shift from 25°C to 37°C and is critical for pathogenicity. Intracellular Ca2+ levels increased in hyphae immediately after temperature-induced dimorphism. The chelation of Ca2+ with extracellular (EGTA) or intracellular (BAPTA) calcium chelators inhibited temperature-induced dimorphism, whereas the addition of extracellular Ca2+ accelerated dimorphism. The calcineurin inhibitor cyclosporine A (CsA), but not tacrolimus (FK506), effectively decreased cell growth, halted the M-Y transition that is associated with virulence, and caused aberrant growth morphologies for all forms of P. brasiliensis. The difference between CsA and FK506 was ascribed by the higher levels of cyclophilins contrasted to FKBPs, the intracellular drug targets required for calcineurin suppression. Chronic exposure to CsA abolished intracellular Ca2+ homeostasis and decreased mRNA transcription of the CCH1 gene for the plasma membrane Ca2+ channel in yeast-form cells. CsA had no detectable effect on multidrug resistance efflux pumps, while the effect of FK506 on rhodamine excretion was not correlated with the transition to yeast form. In this study, we present evidence that Ca2+/calmodulin-dependent phosphatase calcineurin controls hyphal and yeast morphology, M-Y dimorphism, growth, and Ca2+ homeostasis in P. brasiliensis and that CsA is an effective chemical block for thermodimorphism in this organism. The effects of calcineurin inhibitors on P. brasiliensis reinforce the therapeutic potential of these drugs in a combinatory approach with antifungal drugs to treat endemic paracoccidioidomycosis.

Campos, Claudia B. L.; Di Benedette, Joao Paulo T.; Morais, Flavia V.; Ovalle, Rafael; Nobrega, Marina P.

2008-01-01

14

The cAMP pathway is important for controlling the morphological switch to the pathogenic yeast form of Paracoccidioides brasiliensis  

PubMed Central

Paracoccidioides brasiliensis is a human pathogenic fungus that switches from a saprobic mycelium to a pathogenic yeast. Consistent with the morphological transition being regulated by the cAMP-signalling pathway, there is an increase in cellular cAMP levels both transiently at the onset (< 24 h) and progressively in the later stages (> 120 h) of the transition to the yeast form, and this transition can be modulated by exogenous cAMP. We have cloned the cyr1 gene encoding adenylate cyclase (AC) and established that its transcript levels correlate with cAMP levels. In addition, we have cloned the genes encoding three G? (Gpa1–3), G? (Gpb1) and G? (Gpg1) G proteins. Gpa1 and Gpb1 interact with one another and the N-terminus of AC, but neither Gpa2 nor Gpa3 interacted with Gpb1 or AC. The interaction of Gpa1 with Gpb1 was blocked by GTP, but its interaction with AC was independent of bound nucleotide. The transcript levels for gpa1, gpb1 and gpg1 were similar in mycelium, but there was a transient excess of gpb1 during the transition, and an excess of gpa1 in yeast. We have interpreted our findings in terms of a novel signalling mechanism in which the activity of AC is differentially modulated by Gpa1 and Gpb1 to maintain the signal over the 10 days needed for the morphological switch.

Chen, Daliang; Janganan, Thamarai K; Chen, Gongyou; Marques, Everaldo R; Kress, Marcia R; Goldman, Gustavo H; Walmsley, Adrian R; Borges-Walmsley, M Ines

2007-01-01

15

Ultrastructure of Dimorphic Transformation in Paracoccidioides brasiliensis  

PubMed Central

The fine structure of Paracoccidioides brasiliensis undergoing temperature-dependent transformation from mycelium to yeast and vice versa (M ? Y) was studied. The transitional form to mycelium from the yeast appears as an elongated bud that extends from the yeast and which has a mixture of characteristics from both the yeast and the mycelium. The transitional form to yeast from the mycelium starts with enlargement of the interseptal spaces and cracking of the outer electron-dense layer of the cell wall of the hypha. Later the interseptal spaces tend to become round and separate. In M ? Y only few interseptal spaces seem to transform. The yeast is produced by self-transformation of the hypha. In Y ? M a new structure is formed and the yeast dies. Intrahyphal hyphae are observed during the transformation from M ? Y, and intrayeast hyphae during the Y ? M. Due to the high mortality and breakage observed in both types of transformations, we believe that wound of the yeast or the mycelium could elicit this phenomenon. Images

Carbonell, Luis M.

1969-01-01

16

Cell organisation, sulphur metabolism and ion transport-related genes are differentially expressed in Paracoccidioides brasiliensis mycelium and yeast cells  

PubMed Central

Background Mycelium-to-yeast transition in the human host is essential for pathogenicity by the fungus Paracoccidioides brasiliensis and both cell types are therefore critical to the establishment of paracoccidioidomycosis (PCM), a systemic mycosis endemic to Latin America. The infected population is of about 10 million individuals, 2% of whom will eventually develop the disease. Previously, transcriptome analysis of mycelium and yeast cells resulted in the assembly of 6,022 sequence groups. Gene expression analysis, using both in silico EST subtraction and cDNA microarray, revealed genes that were differential to yeast or mycelium, and we discussed those involved in sugar metabolism. To advance our understanding of molecular mechanisms of dimorphic transition, we performed an extended analysis of gene expression profiles using the methods mentioned above. Results In this work, continuous data mining revealed 66 new differentially expressed sequences that were MIPS(Munich Information Center for Protein Sequences)-categorised according to the cellular process in which they are presumably involved. Two well represented classes were chosen for further analysis: (i) control of cell organisation – cell wall, membrane and cytoskeleton, whose representatives were hex (encoding for a hexagonal peroxisome protein), bgl (encoding for a 1,3-?-glucosidase) in mycelium cells; and ags (an ?-1,3-glucan synthase), cda (a chitin deacetylase) and vrp (a verprolin) in yeast cells; (ii) ion metabolism and transport – two genes putatively implicated in ion transport were confirmed to be highly expressed in mycelium cells – isc and ktp, respectively an iron-sulphur cluster-like protein and a cation transporter; and a putative P-type cation pump (pct) in yeast. Also, several enzymes from the cysteine de novo biosynthesis pathway were shown to be up regulated in the yeast form, including ATP sulphurylase, APS kinase and also PAPS reductase. Conclusion Taken together, these data show that several genes involved in cell organisation and ion metabolism/transport are expressed differentially along dimorphic transition. Hyper expression in yeast of the enzymes of sulphur metabolism reinforced that this metabolic pathway could be important for this process. Understanding these changes by functional analysis of such genes may lead to a better understanding of the infective process, thus providing new targets and strategies to control PCM.

Andrade, Rosangela V; Paes, Hugo C; Nicola, Andre M; de Carvalho, Maria Jose A; Fachin, Ana Lucia; Cardoso, Renato S; Silva, Simoneide S; Fernandes, Larissa; Silva, Silvana P; Donadi, Eduardo A; Sakamoto-Hojo, Elza T; Passos, Geraldo AS; Soares, Celia MA; Brigido, Marcelo M; Felipe, Maria Sueli S

2006-01-01

17

Caspofungin Affects Growth of Paracoccidioides brasiliensis in Both Morphological Phases ? †  

PubMed Central

Five Paracoccidioides brasiliensis isolates were grown in the presence of caspofungin (0 to 1 ?g/ml). Inhibition of the yeast phase ranged from 20 to 65%, while in the mycelial form it ranged from 75% to 82%. Such variability was loosely related to the amount of cell wall ?-1,3-glucan. No association with point mutations in the ?-1,3-glucan synthase was detected. Caspofungin induced physical changes and cytoplasmic deterioration in both fungal phases.

Rodriguez-Brito, Sabrina; Nino-Vega, Gustavo; San-Blas, Gioconda

2010-01-01

18

In vitro susceptibility testing of Paracoccidioides brasiliensis to sulfonamides.  

PubMed Central

A total of 60 clinical isolates of Paracoccidioides brasiliensis were tested for susceptibility to sulfadiazine and sulfadimethoxyne by the agar dilution technique. A modification of the Mueller-Hinton medium was devised which gave good growth of the yeast form. The minimum inhibitory concentrations for only 51.6% of the isolates were in the range of the recommended blood serum concentration (50 micrograms/ml). For 6 to 8% of the isolates, the minimum inhibitory concentrations were above 200 micrograms of both sulfadiazine and sulfadimethoxyne per ml. A significant decreases in susceptibility was demonstrated for one isolate obtained from a patient relapsing during sulfonamide therapy. Images

Restrepo, A; Arango, M D

1980-01-01

19

Role of host glycosphingolipids on Paracoccidioides brasiliensis adhesion.  

PubMed

Binding of yeast forms to human lung fibroblast cultures was analyzed, aiming to better understand the initial steps of Paracoccidioides brasiliensis infection in humans. A significant P. brasiliensis adhesion was observed either to fibroblasts or to their Triton X-100 insoluble fraction, which contains extracellular matrix and membrane microdomains enriched in glycosphingolipids. Since human lung fibroblasts express at cell-surface gangliosides, such as GM1, GM2, and GM3, the role of these glycosphingolipids on P. brasiliensis adhesion was analyzed by different procedures. Anti-GM3 monoclonal antibody or cholera toxin subunit B (which binds specifically to GM1) reduced significantly fungal adhesion to fibroblast cells, by 35% and 33%, respectively. Direct binding of GM1 to yeast forms of P. brasiliensis was confirmed using cholera toxin subunit B conjugated to AlexaFluor(®)488. It was also demonstrated that P. brasiliensis binds to polystyrene plates coated with galactosylceramide, lactosylceramide, trihexosylceramide, GD3, GM1, GM3, and GD1a, suggesting that glycosphingolipids presenting residues of beta-galactose or neuraminic acid at non-reducing end may act as adhesion molecules for P. brasiliensis. Conversely, no binding was detected when plates were adsorbed with glycosphingolipids that contain terminal residue of beta-N-acetylgalactosamine, such as globoside (Gb4), GM2, and asialo-GM2. In human fibroblast (WI-38 cells), GM3 and GM1 are associated with membrane rafts, which remain insoluble after treatment with Triton X-100 at 4°C. Taken together, these results strongly suggest that lung fibroblast gangliosides, GM3 and GM1, are involved in binding and/or infection by P. brasiliensis. PMID:21057877

Ywazaki, Cristina Y; Maza, Paloma K; Suzuki, Erika; Takahashi, Helio K; Straus, Anita H

2011-05-01

20

Genome size and ploidy of Paracoccidioides brasiliensis reveals a haploid DNA content: Flow cytometry and GP43 sequence analysis  

Microsoft Academic Search

The aim of this study was to evaluate genome size and ploidy of the dimorphic pathogenic fungus Paracoccidioides brasiliensis. The cell cycle analysis of 10 P. brasiliensis isolates by Xow cytometry (FCM) revealed a genome size ranging from 26.3 § 0.1 Mb (26.9 § 0.1 fg) to 35.5 § 0.2 Mb (36.3 § 0.2 fg) per uninucleated yeast cell. The

A. J. Almeida; D. R. Matute; J. A. Carmona; M. Martins; I. Torres; J. G. McEwen; A. Restrepo; C. Leão; P. Ludovico; F. Rodrigues

2006-01-01

21

Phospholipase gene expression during Paracoccidioides brasiliensis morphological transition and infection  

PubMed Central

Phospholipase is an important virulence factor for pathogenic fungi. In this study, we demonstrate the following: (i) the Paracoccidioides brasiliensis pld gene is preferentially expressed in mycelium cells, (ii) the plb1 gene is mostly up-regulated by infection after 6 h of co-infection of MH-S cells or during BALB/c mice lung infection, (iii) during lung infection, plb1, plc and pld gene expression are significantly increased 6-48 h post-infection compared to 56 days after infection, strongly suggesting that phospholipases play a role in the early events of infection, but not during the chronic stages of pulmonary infection by P. brasiliensis.

Soares, Deyze Alencar; Oliveira, Marilia Barros; Evangelista, Adriane Feijo; Venancio, Emerson Jose; Andrade, Rosangela Vieira; Felipe, Maria Sueli Soares; Petrofeza, Silvana

2013-01-01

22

Hygromycin B-resistance phenotype acquired in Paracoccidioides brasiliensis via plasmid DNA integration.  

PubMed

Yeast cells of the human pathogenic fungus Paracoccidioides brasiliensis strain Pb01 were transformed to hygromycin B resistance using the plasmid pAN7.1. Transformation was achieved by electroporation, with intact or linearized plasmid DNA. The fungus was transformed using 200 mM manitol, 5 or 7 kV/cm field strength, 25 microF capacitance, 400 omega resistance, 5 microg plasmid DNA and 10(7) yeast cells in 400 microl, and selected in BHI medium overlaid with 30 microg/ml hygromycin B (hygB). Mitotic stability was assessed by growing transformants on non-selective BHI medium, followed by plating on hygromycin B (30 microg/ml). Transformants were analyzed by PCR and Southern blotting, confirming the hph gene integration into the transformants genome. A low level of stability of the integrated hph sequence in the transformant genomes was observed, probably because of the multinuclearity of P. brasiliensis yeast cells. PMID:16422302

Soares, Renata De B A; Velho, Tarcísio A F; De Moraes, Lidia M P; Azevedo, Maristela O; Soares, Célia M De A; Felipe, Maria Sueli S

2005-12-01

23

Genome size and ploidy of Paracoccidioides brasiliensis reveals a haploid DNA content: Flow cytometry and GP43 sequence analysis  

Microsoft Academic Search

The aim of this study was to evaluate genome size and ploidy of the dimorphic pathogenic fungus Paracoccidioides brasiliensis. The cell cycle analysis of 10 P. brasiliensis isolates by flow cytometry (FCM) revealed a genome size ranging from 26.3±0.1Mb (26.9±0.1fg) to 35.5±0.2Mb (36.3±0.2fg) per uninucleated yeast cell. The DNA content of conidia from P. brasiliensis ATCC 60855—30.2±0.8Mb (30.9±0.8fg) —showed no

A. J. Almeida; D. R. Matute; J. A. Carmona; M. Martins; I. Torres; J. G. McEwen; A. Restrepo; C. Leão; P. Ludovico; F. Rodrigues

2007-01-01

24

Antimicrobial effect of farnesol, a Candida albicans quorum sensing molecule, on Paracoccidioides brasiliensis growth and morphogenesis  

PubMed Central

Background Farnesol is a sesquiterpene alcohol produced by many organisms, and also found in several essential oils. Its role as a quorum sensing molecule and as a virulence factor of Candida albicans has been well described. Studies revealed that farnesol affect the growth of a number of bacteria and fungi, pointing to a potential role as an antimicrobial agent. Methods Growth assays of Paracoccidioides brasiliensis cells incubated in the presence of different concentrations of farnesol were performed by measuring the optical density of the cultures. The viability of fungal cells was determined by MTT assay and by counting the colony forming units, after each farnesol treatment. The effects of farnesol on P. brasiliensis dimorphism were also evaluated by optical microscopy. The ultrastructural morphology of farnesol-treated P. brasiliensis yeast cells was evaluated by transmission and scanning electron microscopy. Results In this study, the effects of farnesol on Paracoccidioides brasiliensis growth and dimorphism were described. Concentrations of this isoprenoid ranging from 25 to 300 ?M strongly inhibited P. brasiliensis growth. We have estimated that the MIC of farnesol for P. brasiliensis is 25 ?M, while the MLC is around 30 ?M. When employing levels which don't compromise cell viability (5 to 15 ?M), it was shown that farnesol also affected the morphogenesis of this fungus. We observed about 60% of inhibition in hyphal development following P. brasiliensis yeast cells treatment with 15 ?M of farnesol for 48 h. At these farnesol concentrations we also observed a significant hyphal shortening. Electron microscopy experiments showed that, despite of a remaining intact cell wall, P. brasiliensis cells treated with farnesol concentrations above 25 ?M exhibited a fully cytoplasmic degeneration. Conclusion Our data indicate that farnesol acts as a potent antimicrobial agent against P. brasiliensis. The fungicide activity of farnesol against this pathogen is probably associated to cytoplasmic degeneration. In concentrations that do not affect fungal viability, farnesol retards the germ-tube formation of P. brasiliensis, suggesting that the morphogenesis of this fungal is controlled by environmental conditions.

Derengowski, Lorena S; De-Souza-Silva, Calliandra; Braz, Shelida V; Mello-De-Sousa, Thiago M; Bao, Sonia N; Kyaw, Cynthia M; Silva-Pereira, Ildinete

2009-01-01

25

Exocellular components of Paracoccidioides brasiliensis: identification of a specific antigen.  

PubMed Central

Yeast forms of Paracoccidioides brasiliensis grown in liquid medium produced exocellular components. Immunodiffusion reactions and immunoprecipitations of 131I-radiolabeled antigenic components with sera from patients having paracoccidioidomycosis (PCM) were used to monitor the isolation of specific constituents. Components having the main antigenic activity (fCon A) were isolated by exclusion from a Bio-Gel P30 column, followed by successive binding of eluted material to a Sepharose-concanavalin A column, and elution. The product contained, from sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, a minor 43,000-molecular-weight (MW) component (gp43), a polydisperse high-MW glycoconjugate, and a diffusely migrating 55,000-MW glycoprotein (gp55). Other components, including a 72,000-MW glycoprotein, were irregularly expressed. The high-MW glycoconjugate complex contained, on the basis of methylation and 13C nuclear magnetic resonance data, a branched structure of mainly mannopyranosyl units. These were nonreducing ends, 6-O-, 2-O-, and 2,6-di-O-substituted, and the specific rotation of +16 degrees indicated that the glycosidic configurations of the units were alpha and beta in a ratio of ca. 1:1 (concanavalin A binding indicated that nonreducing ends or 2-O-substituted units or both of alpha-D-mannopyranose were present). A small proportion of nonreducing end units of D-galactopyranose were also present in this polysaccharide. gp55 is a glycoprotein containing a complex carbohydrate moiety with fucose, mannose, galactose, and glucose, either as terminal nonreducing units or substituted in positions indicated by methylation data. Both PCM and normal human sera precipitated the high-MW glycoconjugate from 131I-labeled fCon A preparations, whereas gp55 was unreactive with human sera. gp43 was a specific antigenic component of P. brasiliensis culture filtrates which could be isolated in a pure form by gel filtration column chromatography (Sephadex G150) or by Sepharose-patient immunoglobulin G affinity chromatography. 131I-labeled gp43 reacted equally well with 10 PCM sera and hyperimmune rabbit serum against the band E antigen of Yarzabal at a 10(-3) dilution. At the same dilution, no reaction was detected with sera from normal individuals and from patients with other mycoses. Similarly, only PCM sera and the hyperimmune anti-E serum gave precipitin lines with gp43 in the less sensitive immunodiffusion tests. gp43 consisted of three components, with pI 6.7, 6.4 and 6.2, all of which reacted with PCM serum. Images

Puccia, R; Schenkman, S; Gorin, P A; Travassos, L R

1986-01-01

26

Gene expression modulation by paraquat-induced oxidative stress conditions in Paracoccidioides brasiliensis.  

PubMed

Paracoccidioides brasiliensis is a thermodimorphic fungus associated with paracoccidioidomycosis (PCM), the most common systemic mycosis in Latin America. The infection is initiated by inhalation of environmentally dispersed conidia produced by the saprophytic phase of the fungus. In the lungs, P. brasiliensis assumes the parasitic yeast form and must cope with the adverse conditions imposed by cells of the host immune system, which includes a harsh environment, highly concentrated in reactive oxygen species (ROS). In this work, we used the ROS-generating agent paraquat to experimentally simulate oxidative stress conditions in order to evaluate the stress-induced modulation of gene expression in cultured P. brasiliensis yeast cells, using a microarray hybridization approach. The large-scale evaluation inherent to microarray-based analyses identified 2070 genes differentially transcribed in response to paraquat exposure, allowing an integrated visualization of the major metabolic changes that constitute the systemic defense mechanism used by the fungus to overcome the deleterious effects of ROS. These include overexpression of detoxifying agents, as well as of molecular scavengers and genes involved in maintenance of the intracellular redox potential. Particularly noteworthy was to verify that the oxidative stress resistance mechanism of P. brasiliensis also involves coordinated overexpression of a series of genes responsible for chitin-biosynthesis, suggesting that this pathway may constitute a specific regulon. Further analyses aiming at confirming and understanding the mechanisms that control such regulon may provide interesting new targets for chemotherapeutic approaches against P. brasiliensis and other pathogenic fungi. PMID:23711636

de Oliveira, Marcus Vinícius; Oliveira, Ana Claudia de Freitas; Shida, Cláudio S; de Oliveira, Regina Costa; Nunes, Luiz R

2013-11-01

27

Synergistic interaction of trimethoprim and sulfamethoxazole on Paracoccidioides brasiliensis.  

PubMed Central

The in vitro interaction of trimethoprim and sulfamethoxazole on clinical isolates of Paracoccidioides brasiliensis was studied. With complete inhibition and a visual endpoint used as the criteria, three of four strains had minimal inhibitory concentrations that indicated resistance to sulfamethoxazole, and all four strains were resistant to trimethoprim. A marked synergism in inhibition was noted with the combination of these drugs against sulfa-resistant strains. A sulfamethoxazole/trimethoprim ratio of 5:1 was the most synergistic. Fifty percent inhibition, determined spectrophotometrically, of the strains could be achieved with sulfamethoxazole alone. In summary, the striking synergy observed suggests that combination chemotherapy with these drugs deserves further study.

Stevens, D A; Vo, P T

1982-01-01

28

Detection of antibodies against Paracoccidioides brasiliensis melanin in in vitro and in vivo studies during infection.  

PubMed

Several cell wall constituents, including melanins or melanin-like compounds, have been implicated in the pathogenesis of a wide variety of microbial diseases caused by diverse species of pathogenic bacteria, fungi, and helminthes. Among these microorganisms, the dimorphic fungal pathogen Paracoccidioides brasiliensis produces melanin in its conidial and yeast forms. In the present study, melanin particles from P. brasiliensis were injected into BALB/c mice in order to produce monoclonal antibodies (MAbs). We identified five immunoglobulin G1 (IgG1) ?-chain and four IgM melanin-binding MAbs. The five IgG1 ?-chain isotypes are the first melanin-binding IgG MAbs ever reported. The nine MAbs labeled P. brasiliensis conidia and yeast cells both in vitro and in pulmonary tissues. The MAbs cross-reacted with melanin-like purified particles from other fungi and also with commercial melanins, such as synthetic and Sepia officinalis melanin. Melanization during paracoccidioidomycosis (PCM) was also further supported by the detection of IgG antibodies reactive to melanin from P. brasiliensis conidia and yeast in sera and bronchoalveolar lavage fluids from P. brasiliensis-infected mice, as well as in sera from human patients with PCM. Serum specimens from patients with other mycoses were also tested for melanin-binding antibodies by enzyme-linked immunosorbent assay, and cross-reactivities were detected for melanin particles from different fungal sources. These results suggest that melanin from P. brasiliensis is an immunologically active fungal structure that activates a strong IgG humoral response in humans and mice. PMID:21813659

Urán, Martha E; Nosanchuk, Joshua D; Restrepo, Angela; Hamilton, Andrew J; Gómez, Beatriz L; Cano, Luz E

2011-10-01

29

Cryptic species of Paracoccidioides brasiliensis: impact on paracoccidioidomycosis immunodiagnosis  

PubMed Central

We aimed to evaluate whether the occurrence of cryptic species of Paracoccidioides brasiliensis, S1, PS2, PS3 and Paracoccidioides lutzii, has implications in the immunodiagnosis of paracoccidioidomycosis (PCM). Small quantities of the antigen gp43 were found in culture filtrates of P. lutzii strains and this molecule appeared to be more variable within P. lutzii because the synonymous-nonsynonymous mutation rate was lower, indicating an evolutionary process different from that of the remaining genotypes. The production of gp43 also varied between isolates belonging to the same species, indicating that speciation events are important, but not sufficient to fully explain the diversity in the production of this antigen. The culture filtrate antigen AgEpm83, which was obtained from a PS3 isolate, showed large quantities of gp43 and reactivity by immunodiffusion assays, similar to the standard antigen (AgB-339) from an S1 isolate. Furthermore, AgEpm83 was capable of serologically differentiating five serum samples from patients from the Botucatu and Jundiaí regions. These patients had confirmed PCM but, were non-reactive to the standard antigen, thus demonstrating an alternative for serological diagnosis in regions in which S1 and PS2 occur. We also emphasise that it is not advisable to use a single antigen preparation to diagnose PCM, a disease that is caused by highly diverse pathogens.

Machado, Gabriel Capella; Moris, Daniela Vanessa; Arantes, Thales Domingos; Silva, Luciane Regina Franciscone; Theodoro, Raquel Cordeiro; Mendes, Rinaldo Poncio; Vicentini, Adriana Pardini; Bagagli, Eduardo

2013-01-01

30

DOSE RESPONSE EFFECT OF Paracoccidioides brasiliensis IN AN EXPERIMENTAL MODEL OF ARTHRITIS  

PubMed Central

Paracoccidioidomycosis (PCM) is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb) and corresponds to prevalent systemic mycosis in Latin America. The aim of the present work was to evaluate the dose response effect of the fungal yeast phase for the standardization of an experimental model of septic arthritis. The experiments were performed with groups of 14 rats that received doses of 103, 104 or 105 P. brasiliensis (Pb18) cells. The fungi were injected in 50 µL of phosphate-buffered saline (PBS) directly into the knee joints of the animals. The following parameters were analyzed in this work: the formation of swelling in knees infused with yeast cells and the radiological and anatomopathological alterations, besides antibody titer by ELISA. After 15 days of infection, signs of inflammation were evident. At 45 days, some features of damage and necrosis were observed in the articular cartilage. The systemic dissemination of the fungus was observed in 11% of the inoculated animals, and it was concluded that the experimental model is able to mimic articular PCM in humans and that the dose of 105 yeast cells can be used as standard in this model.

Loth, Eduardo Alexandre; Biazim, Samia Khalil; dos Santos, Jose Henrique Fermino Ferreira; Puccia, Rosana; Brancalhao, Rosimeire Costa; Chasco, Lucineia de Fatima; Gandra, Rinaldo Ferreira; Simao, Rita de Cassia Garcia; de Franco, Marcello Fabiano

2014-01-01

31

Identification of human plasma proteins associated to the cell wall of the pathogenic fungus Paracoccidioides brasiliensis  

PubMed Central

Paracoccidioides brasiliensis and P. lutzii are thermodimorphic species that cause paracoccidioidomycosis. The cell wall is the outermost fungal organelle to form an interface with the host. A number of host effector compounds, including immunologically active molecules, circulate in the plasma. In the present work we extracted cell wall-associated proteins from the yeast pathogenic phase of P. brasiliensis, isolate Pb3, grown in the presence of human plasma, and analyzed bound plasma proteins by liquid chromatography-tandem mass spectrometry. Transport, complement activation/regulation and coagulation pathway were the most abundant functional groups identified. Proteins related to iron/copper acquisition, immunoglobulins, and protease inhibitors were also detected. Several human plasma proteins described here have not been previously reported as interacting with fungal components, specifically, clusterin, hemopexin, transthyretin, ceruloplasmin, alpha-1-antitrypsin, apolipoprotein A-I, and apolipoprotein B-100. Additionally, we observed increased phagocytosis by J774.16 macrophages of Pb3 grown in plasma, suggesting that plasma proteins interacting with P. brasiliensis cell wall might be interfering in the fungal relationship with the host.

Longo, LVG; Nakayasu, ES; Matsuo, AL; Peres da Silva, R; Sobreira, TJP; Vallejo, MC; Ganiko, L; Almeida, IC; Puccia, R

2013-01-01

32

Paracoccidioides brasiliensis PbP27 gene: knockdown procedures and functional characterization.  

PubMed

Paracoccidioides brasiliensis PbP27 gene encodes a protein localized in both the fungal cytoplasm and cell wall. The parasitic infectious form produces this protein preferentially with the gene's expression varying between the fungus phylogenetic species. The biological function of the native p27 has yet to be determined during either growth of the yeast or host infection. Therefore, in this study, through the use of antisense RNA technology and Agrobacterium tumefaciens-mediated transformation, we generated mitotically stable PbP27 mutants (PbP27 aRNA) with the goal to evaluate the role of p27 in the biology and virulence of this fungus. PbP27 expression was reduced 60-75% in mutants, as determined by real-time PCR in correlation with a decrease in p27 expression. No alterations in the growth curve or in the ability to shift from mycelia to yeast or from yeast to mycelia were observed in PbP27 aRNA strains; however, we did observe a reduction in cell vitality. Moreover, a decrease in cell viability of PbP27 aRNA yeast cells after interaction with IFN-?-stimulated macrophages was detected. Based on these results, we propose that p27 plays a role in yeast cell architecture and represents one of the mechanisms employed by this fungus for its interaction with the monocyte/macrophage system. PMID:24118983

Torres, Isaura; Hernandez, Orville; Tamayo, Diana; Muñoz, Jose F; García, Ana M; Gómez, Beatriz L; Restrepo, Angela; McEwen, Juan G

2014-03-01

33

Detection of gp43 of Paracoccidioides brasiliensis by the loop-mediated isothermal amplification (LAMP) method  

Microsoft Academic Search

Paracoccidioidomycosis is a deep mycosis caused by the thermo-dependent dimorphic fungus Paracoccidioides brasiliensis and is prevalent in Latin American countries. We detected the species specific gp43 gene of P. brasiliensis by loop-mediated isothermal amplification (LAMP) in 22 clinical and seven armadillo-derived isolates. The amplified DNA appeared as a ladder with a specific banding pattern. The advantage of the LAMP method

Shigeo Endo; Takashi Komori; Giannina Ricci; Ayako Sano; Koji Yokoyama; Akira Ohori; Katsuhiko Kamei; Marcello Franco; Makoto Miyaji; Kazuko Nishimura

2004-01-01

34

Immunological characterization of a recombinant 27-kilodalton antigenic protein from Paracoccidioides brasiliensis.  

PubMed Central

We report the expression in Escherichia coli of a 27-kDa antigenic protein from Paracoccidioides brasiliensis. When analyzed by immunoblotting, this recombinant antigenic protein was recognized by antibodies present in the sera of 40 of the 44 paracoccidioidomycosis patients studied. No cross-reactions were observed with sera from patients with other mycoses (histoplasmosis, aspergillosis, cryptococcosis, sporotrichosis, and chromoblastomycosis) or with tuberculosis.

Ortiz, B L; Garcia, A M; Restrepo, A; McEwen, J G

1996-01-01

35

Importance of xenarthrans in the eco-epidemiology of Paracoccidioides brasiliensis  

Microsoft Academic Search

BACKGROUND: Several pathogens that cause important zoonotic diseases have been frequently associated with armadillos and other xenarthrans. This mammal group typically has evolved on the South American continent and many of its extant species are seriously threatened with extinction. Natural infection of armadillos with Paracoccidioides brasiliensis in hyperendemic areas has provided a valuable opportunity for understanding the role of this

Virgínia B Richini-Pereira; Sandra MG Bosco; Raquel C Theodoro; Lígia Barrozo; Silvia CB Pedrini; Patrícia S Rosa; Eduardo Bagagli

2009-01-01

36

The malate synthase of Paracoccidioides brasiliensis is a linked surface protein that behaves as an anchorless adhesin  

PubMed Central

Background The pathogenic fungus Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis (PCM). This is a pulmonary mycosis acquired by inhalation of fungal airborne propagules that can disseminate to several organs and tissues leading to a severe form of the disease. Adhesion and invasion to host cells are essential steps involved in the internalization and dissemination of pathogens. Inside the host, P. brasiliensis may use the glyoxylate cycle for intracellular survival. Results Here, we provide evidence that the malate synthase of P. brasiliensis (PbMLS) is located on the fungal cell surface, and is secreted. PbMLS was overexpressed in Escherichia coli, and polyclonal antibody was obtained against this protein. By using Confocal Laser Scanning Microscopy, PbMLS was detected in the cytoplasm and in the cell wall of the mother, but mainly of budding cells of the P. brasiliensis yeast phase. PbMLSr and its respective polyclonal antibody produced against this protein inhibited the interaction of P. brasiliensis with in vitro cultured epithelial cells A549. Conclusion These observations indicated that cell wall-associated PbMLS could be mediating the binding of fungal cells to the host, thus contributing to the adhesion of fungus to host tissues and to the dissemination of infection, behaving as an anchorless adhesin.

2009-01-01

37

[In vitro infection by different strains of Paracoccidioides brasiliensis].  

PubMed

We analyzed the in vitro infection process by P. brasiliensis and the effect of extracellular factor(s) produced on monolayers of mammalian Vero cell lines. The yeast phase of four strains was studied: B339 (avirulent or slightly virulent), U, (intermediate virulence), 93745 and 63265 (both highly virulent). Strains of intermediate and high virulence had higher adherence at first contact (about 16%). Strain B339 had a slower adherence at first contact (8%) than the others during the same period. The production of extracellular proteases, soluble extracellular factor(s) and extracellular antigen gP43 showed no correlation with the in vitro physiopathogenicity of the analyzed strains. We demonstrate that the Vero model presented in this paper is a suitable system to study infection and virulence in vitro. We are currently assessing its usefulness as a tool for the analysis of the interaction between pathogen, host and antifungal agents. PMID:11008702

Canteros, C E; Soria, M A; Rivas, M C; Pérez, C; Tous, M; Lee, W; Rodero, L; Davel, G

2000-01-01

38

Low Concentrations of Hydrogen Peroxide or Nitrite Induced of Paracoccidioides brasiliensis Cell Proliferation in a Ras-Dependent Manner  

PubMed Central

Paracoccidioides brasiliensis, a causative agent of paracoccidioidomycosis (PCM), should be able to adapt to dramatic environmental changes inside the infected host after inhalation of air-borne conidia and transition to pathogenic yeasts. Proteins with antioxidant functions may protect fungal cells against reactive oxygen (ROS) and nitrogen (RNS) species generated by phagocytic cells, thus acting as potential virulence factors. Ras GTPases are involved in stress responses, cell morphology, and differentiation in a range of organisms. Ras, in its activated form, interacts with effector proteins and can initiate a kinase cascade. In lower eukaryotes, Byr2 kinase represents a Ras target. The present study investigated the role of Ras in P. brasiliensis after in vitro stimulus with ROS or RNS. We have demonstrated that low concentrations of H2O2 (0.1 mM) or NO2 (0.1–0.25 µM) stimulated P. brasiliensis yeast cell proliferation and that was not observed when yeast cells were pre-incubated with farnesyltransferase inhibitor. We constructed an expression plasmid containing the Byr2 Ras-binding domain (RBD) fused with GST (RBD-Byr2-GST) to detect the Ras active form. After stimulation with low concentrations of H2O2 or NO2, the Ras active form was observed in fungal extracts. Besides, NO2 induced a rapid increase in S-nitrosylated Ras levels. This alternative posttranslational modification of Ras, probably in residue Cys123, would lead to an exchange of GDP for GTP and consequent GTPase activation in P. brasiliensis. In conclusion, low concentrations of H2O2 or NO2 stimulated P. brasiliensis proliferation through Ras activation.

Haniu, Ana Eliza Coronel Janu; Maricato, Juliana Terzi; Mathias, Pedro Paulo Moraes; Castilho, Daniele Goncalves; Miguel, Rodrigo Bernardi; Monteiro, Hugo Pequeno; Puccia, Rosana; Batista, Wagner Luiz

2013-01-01

39

A 32-Kilodalton Hydrolase Plays an Important Role in Paracoccidioides brasiliensis Adherence to Host Cells and Influences Pathogenicity?  

PubMed Central

One of the most crucial events during infection with the dimorphic fungus Paracoccidioides brasiliensis is adhesion to pulmonary epithelial cells, a pivotal step in the establishment of disease. In this study, we have evaluated the relevance of a 32-kDa protein, a putative adhesion member of the haloacid dehalogenase (HAD) superfamily of hydrolases, in the virulence of this fungus. Protein sequence analyses have supported the inclusion of PbHad32p as a hydrolase and have revealed a conserved protein only among fungal dimorphic and filamentous pathogens that are closely phylogenetically related. To evaluate its role during the host-pathogen interaction, we have generated mitotically stable P. brasiliensis HAD32 (PbHAD32) antisense RNA (aRNA) strains with consistently reduced gene expression. Knockdown of PbHAD32 did not alter cell vitality or viability but induced morphological alterations in yeast cells. Moreover, yeast cells with reduced PbHAD32 expression were significantly affected in their capacity to adhere to human epithelial cells and presented decreased virulence in a mouse model of infection. These data support the hypothesis that PbHad32p binds to extracellular matrix (ECM) proteins and modulates the initial immune response for evasion of host defenses. Our findings point to PbHAD32 as a novel virulence factor active during the initial interaction with host cells in P. brasiliensis.

Hernandez, Orville; Almeida, Agostinho J.; Gonzalez, Angel; Garcia, Ana Maria; Tamayo, Diana; Cano, Luz Elena; Restrepo, Angela; McEwen, Juan G.

2010-01-01

40

CellWallComposition oftheYeastandMycelial FormsofParacoccidioides brasiliensis  

Microsoft Academic Search

Isolation andchemical analyses ofthecell walls oftheyeast(Yform)andmyce- lial forms(M form)ofParacoccidioides brasiliensis andBlastomyces dermatitidis revealed that their chemical composition issimilar anddepends on theform.Lipids, chitin, glucans, andproteins arethemainconstituents ofthecell walls ofbothforms ofthese fungi. Thereisno significant difference intheamountoflipids (5to10%) andglucans (36to47%0)contained bythetwoforms. Inbothfungi, theY form hasa larger amountofchitin (37to48%)thantheM form(7to18%c), whereas theM formhasalarger amountofproteins (24to41%c) thantheY form(7to14%). Several properties oftheglucan ofP.brasiliensis were studied. Almostallofthe

FUMINORI KANETSUNA; RAMON E. MORENO

1969-01-01

41

Interaction between Paracoccidioides brasiliensis conidia and the coagulation system: involvement of fibrinogen.  

PubMed

The infectious process starts with an initial contact between pathogen and host. We have previously demonstrated that Paracoccidioides brasiliensis conidia interact with plasma proteins including fibrinogen, which is considered the major component of the coagulation system. In this study, we evaluated the in vitro capacity of P. brasiliensis conidia to aggregate with plasma proteins and compounds involved in the coagulation system. We assessed the aggregation of P. brasiliensis conidia after incubation with human serum or plasma in the presence or absence of anticoagulants, extracellular matrix (ECM) proteins, metabolic and protein inhibitors, monosaccharides and other compounds. Additionally, prothrombin and partial thromboplastin times were determined after the interaction of P. brasiliensis conidia with human plasma. ECM proteins, monosaccharides and human plasma significantly induced P. brasiliensis conidial aggregation; however, anticoagulants and metabolic and protein inhibitors diminished the aggregation process. The extrinsic coagulation pathway was not affected by the interaction between P. brasiliensis conidia and plasma proteins, while the intrinsic pathway was markedly altered. These results indicate that P. brasiliensis conidia interact with proteins involved in the coagulation system. This interaction may play an important role in the initial inflammatory response, as well as fungal disease progression caused by P. brasiliensis dissemination. PMID:23827999

Tamayo, Diana; Hernández, Orville; Muñoz-Cadavid, Cesar; Cano, Luz Elena; González, Angel

2013-06-01

42

Interaction between Paracoccidioides brasiliensis conidia and the coagulation system: involvement of fibrinogen  

PubMed Central

The infectious process starts with an initial contact between pathogen and host. We have previously demonstrated that Paracoccidioides brasiliensis conidia interact with plasma proteins including fibrinogen, which is considered the major component of the coagulation system. In this study, we evaluated the in vitro capacity of P. brasiliensis conidia to aggregate with plasma proteins and compounds involved in the coagulation system. We assessed the aggregation of P. brasiliensis conidia after incubation with human serum or plasma in the presence or absence of anticoagulants, extracellular matrix (ECM) proteins, metabolic and protein inhibitors, monosaccharides and other compounds. Additionally, prothrombin and partial thromboplastin times were determined after the interaction of P. brasiliensis conidia with human plasma. ECM proteins, monosaccharides and human plasma significantly induced P. brasiliensis conidial aggregation; however, anticoagulants and metabolic and protein inhibitors diminished the aggregation process. The extrinsic coagulation pathway was not affected by the interaction between P. brasiliensis conidia and plasma proteins, while the intrinsic pathway was markedly altered. These results indicate that P. brasiliensis conidia interact with proteins involved in the coagulation system. This interaction may play an important role in the initial inflammatory response, as well as fungal disease progression caused by P. brasiliensis dissemination.

Tamayo, Diana; Hernandez, Orville; Munoz-Cadavid, Cesar; Cano, Luz Elena; Gonzalez, Angel

2013-01-01

43

Paracoccidioides brasiliensis and P. lutzii antigens elicit different serum IgG responses in chronic paracoccidioidomycosis.  

PubMed

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by the fungus Paracoccidioides brasiliensis (S1, PS2, and PS3) and by the new species, P. lutzii. Considering that genetic differences in the Paracoccidioides genus could elicit distinct immune responses by the host, current research investigated serum IgG levels to antigens from P. brasiliensis B339 (S1), P. brasiliensis LDR3 (PS2), and atypical strain LDR2 (P. lutzii), in patients with chronic PCM from the northern and west regions of Paraná, Brazil (n = 35). Cell-free antigen (CFA) and high molecular mass fraction (hMM) were produced from each strain. Samples were analyzed by ELISA and immunodiffusion (ID). ELISA positivity using CFA: B339-100 %, LDR3-83 %, and LDR2-74 %. Response to CFA from B339 was more intense (p < 0.05), while there was no difference between LDR3-LDR2. IgG anti-hMM was higher for antigens from B339 or LDR3, when compared with LDR2 (p < 0.05). There was a positive correlation for each strain between CFA-hMM and for hMM between B339-LDR3 and LDR3-LDR2. ID positivity with CFA: B339-63 %, LDR3-66 %, and LDR2-60 %. We conclude that the intensity of reaction of the patients' sera varies with the strain used; hMM influences tests that use CFA, independently of strain; using ID, positive rates were very similar, but there was a large number of false negative results; ELISA tests using antigens from P. brasiliensis S1 were able to detect a larger number of patients than PS2 and P. lutzii (which had a considerable number of false negative results), and therefore, its use may be more appropriate in this region of Brazil. PMID:24005606

Lenhard-Vidal, A; Assolini, J P; Ono, M A; Bredt, C S O; Sano, A; Itano, E N

2013-12-01

44

Ecological study of Paracoccidioides brasiliensis in soil: growth ability, conidia production and molecular detection  

PubMed Central

Background Paracoccidioides brasiliensis ecology is not completely understood, although several pieces of evidence point to the soil as its most probable habitat. The present study aimed to investigate the fungal growth, conidia production and molecular pathogen detection in different soil conditions. Methods Soils samples of clayey, sandy and medium textures were collected from ground surface and the interior of armadillo burrows in a hyperendemic area of Paracoccidioidomycosis. P. brasiliensis was inoculated in soil with controlled humidity and in culture medium containing soil extracts. The molecular detection was carried out by Nested PCR, using panfungal and species specific primers from the ITS-5.8S rDNA region. Results The soil texture does not affect fungus development and the growth is more abundant on/in soil saturated with water. Some soil samples inhibited the development of P. brasiliensis, especially those that contain high values of Exchangeable Aluminum (H+Al) in their composition. Some isolates produced a large number of conidia, mainly in soil-extract agar medium. The molecular detection was positive only in samples collected from armadillo burrows, both in sandy and clayey soil. Conclusion P. brasiliensis may grow and produce the infectious conidia in sandy and clayey soil, containing high water content, mainly in wild animal burrows, but without high values of H+Al.

Tercarioli, Gisela Ramos; Bagagli, Eduardo; Reis, Gabriela Martins; Theodoro, Raquel Cordeiro; Bosco, Sandra De Moraes Gimenes; Macoris, Severino Assis da Graca; Richini-Pereira, Virginia Bodelao

2007-01-01

45

The transcriptome analysis of early morphogenesis in Paracoccidioides brasiliensis mycelium reveals novel and induced genes potentially associated to the dimorphic process  

PubMed Central

Background Paracoccidioides brasiliensis is a human pathogen with a broad distribution in Latin America. The fungus is thermally dimorphic with two distinct forms corresponding to completely different lifestyles. Upon elevation of the temperature to that of the mammalian body, the fungus adopts a yeast-like form that is exclusively associated with its pathogenic lifestyle. We describe expressed sequence tags (ESTs) analysis to assess the expression profile of the mycelium to yeast transition. To identify P. brasiliensis differentially expressed sequences during conversion we performed a large-scale comparative analysis between P. brasiliensis ESTs identified in the transition transcriptome and databases. Results Our analysis was based on 1107 ESTs from a transition cDNA library of P. brasiliensis. A total of 639 consensus sequences were assembled. Genes of primary metabolism, energy, protein synthesis and fate, cellular transport, biogenesis of cellular components were represented in the transition cDNA library. A considerable number of genes (7.51%) had not been previously reported for P. brasiliensis in public databases. Gene expression analysis using in silico EST subtraction revealed that numerous genes were more expressed during the transition phase when compared to the mycelial ESTs [1]. Classes of differentially expressed sequences were selected for further analysis including: genes related to the synthesis/remodeling of the cell wall/membrane. Thirty four genes from this family were induced. Ten genes related to signal transduction were increased. Twelve genes encoding putative virulence factors manifested increased expression. The in silico approach was validated by northern blot and semi-quantitative RT-PCR. Conclusion The developmental program of P. brasiliensis is characterized by significant differential positive modulation of the cell wall/membrane related transcripts, and signal transduction proteins, suggesting the related processes important contributors to dimorphism. Also, putative virulence factors are more expressed in the transition process suggesting adaptation to the host of the yeast incoming parasitic phase. Those genes provide ideal candidates for further studies directed at understanding fungal morphogenesis and its regulation.

Bastos, Karinne P; Bailao, Alexandre M; Borges, Clayton L; Faria, Fabricia P; Felipe, Maria SS; Silva, Mirelle G; Martins, Wellington S; Fiuza, Rogerio B; Pereira, Maristela; Soares, Celia MA

2007-01-01

46

Inhibition of PbGP43 Expression May Suggest that gp43 is a Virulence Factor in Paracoccidioides brasiliensis  

PubMed Central

Glycoprotein gp43 is an immunodominant diagnostic antigen for paracoccidioidomycosis caused by Paracoccidioides brasiliensis. It is abundantly secreted in isolates such as Pb339. It is structurally related to beta-1,3-exoglucanases, however inactive. Its function in fungal biology is unknown, but it elicits humoral, innate and protective cellular immune responses; it binds to extracellular matrix-associated proteins. In this study we applied an antisense RNA (aRNA) technology and Agrobacterium tumefaciens-mediated transformation to generate mitotically stable PbGP43 mutants (PbGP43 aRNA) derived from wild type Pb339 to study its role in P. brasiliensis biology and during infection. Control PbEV was transformed with empty vector. Growth curve, cell vitality and morphology of PbGP43 aRNA mutants were indistinguishable from those of controls. PbGP43 expression was reduced 80–85% in mutants 1 and 2, as determined by real time PCR, correlating with a massive decrease in gp43 expression. This was shown by immunoblotting of culture supernatants revealed with anti-gp43 mouse monoclonal and rabbit polyclonal antibodies, and also by affinity-ligand assays of extracellular molecules with laminin and fibronectin. In vitro, there was significantly increased TNF-? production and reduced yeast recovery when PbGP43 aRNA1 was exposed to IFN-?-stimulated macrophages, suggesting reduced binding/uptake and/or increased killing. In vivo, fungal burden in lungs of BALB/c mice infected with silenced mutant was negligible and associated with decreased lung ???10 and IL-6. Therefore, our results correlated low gp43 expression with lower pathogenicity in mice, but that will be definitely proven when PbGP43 knockouts become available. This is the first study of gp43 using genetically modified P. brasiliensis.

Torres, Isaura; Hernandez, Orville; Tamayo, Diana; Munoz, Jose F.; Leitao, Natanael P.; Garcia, Ana M.; Restrepo, Angela

2013-01-01

47

Immunohistochemical detection of a novel 22- to 25-kilodalton glycoprotein of Paracoccidioides brasiliensis in biopsy material and partial characterization by using species-specific monoclonal antibodies.  

PubMed Central

Two murine monoclonal antibodies (MAbs) specific to Paracoccidioides brasiliensis (as determined by enzyme-linked immunosorbent assay [ELISA] and Western blot [immunoblot]) were produced by using a modification of standard hybridization protocols, with cyclophosphamide included as an immunomodulator to abolish responses to highly cross-reactive immunodominant epitopes. MAbs PS14 and PS15 are two different clones which exhibit similar characteristics by ELISA and Western blot. They are directed against a 22- to 25-kDa antigen which is present in P. brasiliensis and which could not be identified in other dimorphic fungi by ELISA or Western blot. Partial purification of the antigen was accomplished by isoelectric focusing, and deglycosylation studies suggested that the 22- to 25-kDa antigen is a glycoprotein with a pI of between 4.5 and 5 and that O-linked sugars may be part of the recognized epitope. The MAbs stained the cytoplasm of P. brasiliensis yeast and hyphal cells in cryostat sections of fresh cultures of the fungus. In addition, the MAbs stained the wall of paracoccidioidomycotic granulomas, as well as the cytoplasm of the fungus, as determined by the use of immunofluorescence, immunoperoxidase, and immuno-alkaline phosphatase staining techniques in paraffin-embedded sections of human biopsy material, and they failed to stain granulomas resulting from other clinical conditions. These findings suggest that these MAbs have potential use in the immunohistochemical identification of P. brasiliensis. Images

Figueroa, J I; Hamilton, A; Allen, M; Hay, R

1994-01-01

48

Importance of xenarthrans in the eco-epidemiology of Paracoccidioides brasiliensis  

PubMed Central

Background Several pathogens that cause important zoonotic diseases have been frequently associated with armadillos and other xenarthrans. This mammal group typically has evolved on the South American continent and many of its extant species are seriously threatened with extinction. Natural infection of armadillos with Paracoccidioides brasiliensis in hyperendemic areas has provided a valuable opportunity for understanding the role of this mammal in the eco-epidemiology of Paracoccidioidomycosis (PCM), one of the most important systemic mycoses in Latin America. Findings This study aimed to detect P. brasiliensis in different xenarthran species (Dasypus novemcinctus, Cabassous spp., Euphractus sexcinctus, Tamandua tetradactyla and Myrmecophaga tridactyla), by molecular and mycological approaches, in samples obtained by one of the following strategies: i) from road-killed animals (n = 6); ii) from naturally dead animals (n = 8); iii) from animals that died in captivity (n = 9); and iv) from living animals captured from the wild (n = 2). Specific P. brasiliensis DNA was detected in several organs among 7/20 nine-banded armadillos (D. novemcinctus) and in 2/2 anteaters (M. tridactyla). The fungus was also cultured in tissue samples from one of two armadillos captured from the wild. Conclusion Members of the Xenarthra Order, especially armadillos, have some characteristics, including a weak cellular immune response and low body temperature, which make them suitable models for studying host-pathogen interaction. P. brasiliensis infection in wild animals, from PCM endemic areas, may be more common than initially postulated and reinforces the use of these animals as sentinels for the pathogen in the environment.

2009-01-01

49

Histological and ultrastructural study of the inflammation evoked by Paracoccidioides brasiliensis antigen in previously immunized mice.  

PubMed

Bentonite particles uncoated and coated with soluble antigen of Paracoccidioides brasiliensis (Pb) were intravenously injected into mice with and without previous immunization with Pb antigen. The inflammatory reaction around the bentonite emboli in small lung vessels was quantitated and morphologically studied by light and electron (EM) microscopy, 2 to 8 days after challenge. In control nonimmunized animals, coated and uncoated bentonite particles caused mild and nonspecific inflammation made up by macrophages. By EM, they formed loosely aggregated clusters with cytoplasm containing few organelles and borders without interdigitation. In immunized mice injected with coated bentonite particles, the inflammatory area was significantly greater than that in nonimmunized animals in all periods of study with maximum difference at day 2. The inflammatory process at days 2 and 4 was characterized as mature granulomata, composed of macrophages with great number of organelles in the cytoplasm, large euchromatic nuclei and prominent nucleoli. Altogether these findings indicated a lesion with high metabolic activity, compatible with a granulomatous hypersensitivity reaction. At days 6 and 8, there was a change from mature to epithelioid granulomata, well demonstrated by EM which showed macrophages with characteristically interdigitated cytoplasmic borders. The results strengthen the importance of cellular immunity in the genesis of epithelioid granuloma in paracoccidioidomycosis and reinforce the usefulness of the present model in studies of the inflammatory cellular sequency and events in this mycosis. PMID:2739693

Defaveri, J; Martin, L C; Franco, M

1989-01-01

50

Prophylactic and Therapeutic Vaccination Using Dendritic Cells Primed with Peptide 10 Derived from the 43-Kilodalton Glycoprotein of Paracoccidioides brasiliensis  

PubMed Central

Vaccination with peptide 10 (P10), derived from the Paracoccidioides brasiliensis glycoprotein 43 (gp43), induces a Th1 response that protects mice in an intratracheal P. brasiliensis infection model. Combining P10 with complete Freund's adjuvant (CFA) or other adjuvants further increases the peptide's antifungal effect. Since dendritic cells (DCs) are up to 1,000-fold more efficient at activating T cells than CFA, we examined the impact of P10-primed bone-marrow-derived DC vaccination in mice. Splenocytes from mice immunized with P10 were stimulated in vitro with P10 or P10-primed DCs. T cell proliferation was significantly increased in the presence of P10-primed DCs compared to the peptide. The protective efficacy of P10-primed DCs was studied in an intratracheal P. brasiliensis model in BALB/c mice. Administration of P10-primed DCs prior to (via subcutaneous vaccination) or weeks after (via either subcutaneous or intravenous injection) P. brasiliensis infection decreased pulmonary damage and significantly reduced fungal burdens. The protective response mediated by the injection of primed DCs was characterized mainly by an increased production of gamma interferon (IFN-?) and interleukin 12 (IL-12) and a reduction in IL-10 and IL-4 compared to those of infected mice that received saline or unprimed DCs. Hence, our data demonstrate the potential of P10-primed DCs as a vaccine capable of both the rapid protection against the development of serious paracoccidioidomycosis or the treatment of established P. brasiliensis disease.

Magalhaes, A.; Ferreira, K. S.; Almeida, S. R.; Nosanchuk, J. D.; Travassos, L. R.

2012-01-01

51

The Homeostasis of Iron, Copper, and Zinc in Paracoccidioides Brasiliensis, Cryptococcus Neoformans Var. Grubii, and Cryptococcus Gattii: A Comparative Analysis  

PubMed Central

Iron, copper, and zinc are essential for all living organisms. Moreover, the homeostasis of these metals is vital to microorganisms during pathogenic interactions with a host. Most pathogens have developed specific mechanisms for the uptake of micronutrients from their hosts in order to counteract the low availability of essential ions in infected tissues. We report here an analysis of genes potentially involved in iron, copper, and zinc uptake and homeostasis in the fungal pathogens Paracoccidioides brasiliensis, Cryptococcus neoformans var. grubii, and Cryptococcus gattii. Although prior studies have identified certain aspects of metal regulation in Cryptococcus species, little is known regarding the regulation of these elements in P. brasiliensis. We also present amino acid sequences analyses of deduced proteins in order to examine possible conserved domains. The genomic data reveals, for the first time, genes associated to iron, copper, and zinc assimilation and homeostasis in P. brasiliensis. Furthermore, analyses of the three fungal species identified homologs to genes associated with high-affinity uptake systems, vacuolar and mitochondrial iron storage, copper uptake and reduction, and zinc assimilation. However, homologs to genes involved in siderophore production were only found in P. brasiliensis. Interestingly, in silico analysis of the genomes of P. brasiliensis Pb01, Pb03, and Pb18 revealed significant differences in the presence and/or number of genes involved in metal homeostasis, such as in genes related to iron reduction and oxidation. The broad analyses of the genomes of P. brasiliensis, C. neoformans var. grubii, and C. gattii for genes involved in metal homeostasis provide important groundwork for numerous interesting future areas of investigation that are required in order to validate and explore the function of the identified genes and gene pathways.

Silva, Mirelle Garcia; Schrank, Augusto; Bailao, Elisa Flavia L.C.; Bailao, Alexandre Melo; Borges, Clayton Luiz; Staats, Charley Christian; Parente, Juliana Alves; Pereira, Maristela; Salem-Izacc, Silvia Maria; Mendes-Giannini, Maria Jose Soares; Oliveira, Rosely Maria Zancope; Silva, Livia Kmetzsch Rosa e; Nosanchuk, Joshua D.; Vainstein, Marilene Henning; de Almeida Soares, Celia Maria

2011-01-01

52

Antifungal activity of schinol and a new biphenyl compound isolated from Schinus terebinthifolius against the pathogenic fungus Paracoccidioides brasiliensis  

PubMed Central

Background The aim of this study was to isolate and identify the antifungal compounds from the extracts of Schinus terebinthifolius (Anacardiaceae) against clinical isolates of the pathogenic fungus Paracoccidioides brasiliensis. Methods The hexane and dichlomethane fractions from leaves and stems of S. terebinthifolius were fractionated using several chromatography techniques to afford four compounds. Results The compounds isolated from S. terebinthifolius were identified as schinol (1), a new biphenyl compound, namely, 4'-ethyl-4-methyl-2,2',6,6'-tetrahydroxy[1,1'-biphenyl]-4,4'-dicarboxylate (2), quercetin (3), and kaempferol (4). Compounds 1 and 2 were active against different strains of P. brasiliensis, showing a minimal inhibitory concentration value against the isolate Pb B339 of 15.6 ?g/ml. The isolate Pb 1578 was more sensitive to compound 1 with a MIC value of 7.5 ?g/ml. Schinol presented synergistic effect only when combined with itraconazole. The compounds isolated from S. terebinthifolius were not able to inhibit cell wall synthesis or assembly using the sorbitol assay. Conclusion This work reveals for the first time the occurrence of compound 2 and discloses activity of compounds 1 and 2 against several clinical isolates of P. brasiliensis. These results justify further studies to clarify the mechanisms of action of these compounds.

2010-01-01

53

A proteomic view of the response of Paracoccidioides yeast cells to zinc deprivation.  

PubMed

Zinc plays a critical role in a diverse array of biochemical processes. However, an excess of zinc is deleterious to cells; therefore, cells require finely tuned homeostatic mechanisms to balance the uptake and the storage of zinc. There is also increasing evidence supporting the importance of zinc during infection. To understand better how Paracoccidioides adapts to zinc deprivation, we compared the two-dimensional (2D) gel protein profile of yeast cells during zinc starvation to yeast cells grown in a zinc rich condition. Protein spots were selected for comparative analysis based on the protein staining intensity, as determined by image analysis. In response to zinc deprivation, a total of 423 out of 845 protein spots showed a significant change in abundance. Quantitative RT-qPCR analysis of RNA from Paracoccidioides grown under zinc restricted conditions validated the correlation between the differentially regulated proteins and transcripts. According to the proteomic data, zinc deficiency may be a stressor to Paracoccidioides, as suggested by the upregulation of a number of proteins related to stress response, cell rescue, and virulence. Other process induced by zinc deprivation included gluconeogenesis. Conversely, the methylcitrate cycle was downregulated. Overall, the results indicate a remodelling of the Paracoccidioides response to the probable oxidative stress induced during zinc deprivation. PMID:23809650

Parente, Ana Flávia Alves; de Rezende, Tereza Cristina Vieira; de Castro, Kelly Pacheco; Bailão, Alexandre Melo; Parente, Juliana Alves; Borges, Clayton Luiz; Silva, Luciano Paulino; Soares, Célia Maria de Almeida

2013-06-01

54

Antifungal activity of extracts of some plants used in Brazilian traditional medicine against the pathogenic fungus Paracoccidioides brasiliensis.  

PubMed

Paracoccidioidomycosis (PCM) is a systemic granulomatous disease caused by Paracoccidioides brasiliensis Almeida (Onygenales) that requires 1-2 years of treatment. In the absence of drug therapy, the disease is usually fatal, highlighting the need for the identification of safer, novel, and more effective antifungal compounds. With this need in mind, several plants employed in Brazilian traditional medicine were assayed on P. brasiliensis and murine macrophages. Extracts were prepared from 10 plant species: Inga spp. Mill. (Leguminosae), Schinus terebinthifolius Raddi (Anacardiaceae), Punica granatum L. (Punicaceae), Alternanthera brasiliana Kuntze (Amaranthaceae), Piper regnellii CDC. (Piperaceae), P. abutiloides Kunth (Piperaceae), Herissantia crispa L. Briz. (Malvaceae), Rubus urticaefolius Poir (Rosaceae), Rumex acetosa L. (Polygonaceae), and Baccharis dracunculifolia DC. (Asteraceae). Hexane fractions from hydroalcoholic extracts of Piper regnellii and Baccharis dracunculifolia were the most active against the fungus, displaying minimum inhibitory concentration (MIC) values of 7.8 microg/mL and 7.8-30 mug/mL, respectively. Additionally, neither of the extracts exhibited any apparent cytotoxic effects on murine macrophages at 20 microg/mL. Analyses of these fractions using gas chromatography-mass spectrometry (GC-MS) showed that the major components of B. dracunculifolia were ethyl hydrocinnamate (14.35%) and spathulenol (16.02%), while the major components of the hexane fraction of Piper regnellii were 1-methoxy-4-(1-propenyl) benzene (21.94%) and apiol (21.29%). The activities of these fractions against P. brasiliensis without evidence of cytotoxicity to macrophages justify their investigation as a potential source of new chemical agents for the treatment of PCM. PMID:20645716

Johann, Susana; Cisalpino, Patricia Silva; Watanabe, Gisele Almeida; Cota, Betania Barros; de Siqueira, Ezequias Pessoa; Pizzolatti, Moacir Geraldo; Zani, Carlos Leomar; de Resende, Maria Aparecida

2010-04-01

55

Patients with chronic-form paracoccidioidomycosis present high serum levels of IgE anti-paracoccidioides brasiliensis Gp70.  

PubMed

Paracoccidioidomycosis (PCM) is a disease caused by the Paracoccidioides genus, which includes P. brasiliensis and the new phylogenetic species P. lutzii. Resistance to this infection has been correlated with a Th1 pattern of cellular immune response, while susceptibility is correlated to an intense humoral immune response with an increase in IgE levels. Serum levels of IgE and IgG anti-gp70 and anti-exoantigen in chronic PCM were analyzed by enzyme-linked immunosorbent assay. Results showed a higher gp70 concentration in somatic antigen (SA) than in cell-free antigen (CFA) preparation and significantly higher levels of IgE and IgG anti-gp70 in chronic PCM patients' serum (n = 12) than in normal human serum (n = 12) (p < 0.05). Pearson's correlation analysis showed a strong correlation between IgG and IgE anti-gp70 (r = 0.8424). Additionally, IgE purified from a pool of acute and chronic PCM patient's serum was analyzed by immunoblotting. The patients with the acute form of the disease showed strong bands for gp43 and gp70 in SA but only for gp43 in CFA. In patients with the chronic form, solely the gp43 band was observed. In conclusion, we found that SA is a better source of gp70 than CFA is, and chronic PCM patients show high levels of IgE anti-gp70. This finding suggests that the Th2 immune response is potentially induced by gp70 in PCM disease, which calls for further study. PMID:23397251

Rigobello, F F; Marquez, A S; Lopes, J D; Nakanishi-Ito, F A; Itano, E N

2013-04-01

56

Fate of conidia of Paracoccidioides brasiliensis after ingestion by resident macrophages or cytokine-treated macrophages.  

PubMed Central

Conidia ingested by resident macrophages had an enhanced percentage of transformation to yeast cells compared with those in culture medium without macrophages. The yeast cells subsequently grew intracellularly by budding. Macrophages treated with cytokines from antigen-stimulated spleen cells from immunized mice significantly inhibited transformation of ingested conidia.

Cano, L E; Brummer, E; Stevens, D A; Restrepo, A

1992-01-01

57

Biochemical characterization of Paracoccidioides brasiliensis ?-1,3-glucanase Agn1p, and its functionality by heterologous Expression in Schizosaccharomyces pombe.  

PubMed

?-1,3-Glucan is present as the outermost layer of the cell wall in the pathogenic yeastlike (Y) form of Paracoccidioides brasiliensis. Based on experimental evidence, this polysaccharide has been proposed as a fungal virulence factor. To degrade ?-1,3-glucan and allow remodeling of the cell wall, ?-1,3-glucanase is required. Therefore, the study of this enzyme, its encoding gene, and regulatory mechanisms, might be of interest to understand the morphogenesis and virulence process in this fungus. A single gene, orthologous to other fungal ?-1,3-glucanase genes, was identified in the Paracoccidioides genome, and labeled AGN1. Transcriptional levels of AGN1 and AGS1 (?-1,3-glucan synthase-encoding gene) increased sharply when the pathogenic Y phase was cultured in the presence of 5% horse serum, a reported booster for cell wall ?-1,3-glucan synthesis in this fungus. To study the biochemical properties of P. brasiliensis Agn1p, the enzyme was heterologously overexpressed, purified, and its activity profile determined by means of the degradation of carboxymethyl ?-1,3-glucan (SCMG, chemically modified from P. brasiliensis ?-1,3-glucan), used as a soluble substrate for the enzymatic reaction. Inhibition assays, thin layer chromatography and enzymatic reactions with alternative substrates (dextran, starch, chitin, laminarin and cellulose), showed that Agn1p displays an endolytic cut pattern and high specificity for SCMG. Complementation of a Schizosaccharomyces pombe agn1? strain with the P. brasiliensis AGN1 gene restored the wild type phenotype, indicating functionality of the gene, suggesting a possible role of Agn1p in the remodeling of P. brasiliensis Y phase cell wall. Based on amino acid sequence, P. brasiliensis Agn1p, groups within the family 71 of fungal glycoside hydrolases (GH-71), showing similar biochemical characteristics to other members of this family. Also based on amino acid sequence alignments, we propose a subdivision of fungal GH-71 into at least five groups, for which specific conserved sequences can be identified. PMID:23825576

Villalobos-Duno, Héctor; San-Blas, Gioconda; Paulinkevicius, Maryan; Sánchez-Martín, Yolanda; Nino-Vega, Gustavo

2013-01-01

58

Polymorphism in the flanking regions of the PbGP43 gene from the human pathogen Paracoccidioides brasiliensis: search for protein binding sequences and poly(A) cleavage sites  

Microsoft Academic Search

BACKGROUND: Paracoccidioides brasiliensis is a thermo-dimorphic fungus that causes paracoccidiodomycosis (PCM). Glycoprotein gp43 is the fungal main diagnostic antigen, which can also protect against murine PCM and interact with extracellular matrix proteins. It is structurally related to glucanases, however not active, and whose expression varies considerably. We have presently studied polymorphisms in the PbGP43 flanking regions to help understand such

Antonio A Rocha; Flávia V Morais; Rosana Puccia

2009-01-01

59

Interferon-gamma production by human neutrophils upon stimulation by IL-12, IL-15 and IL-18 and challenge with Paracoccidioides brasiliensis.  

PubMed

Paracoccidiodomycosis is a systemic mycosis caused by the fungus Paracoccidioides brasiliensis (Pb), which is endemic in Latin America. The host innate immune response against the fungus has been well characterized and several studies have shown the important role played by phagocytic cells. Our laboratory has studied the relationship between human neutrophils (PMNs)/Pb, focusing the effector mechanisms of these cells against the fungus. However, in last years, studies have shown that in addition to their phagocytic and killer functions, PMNs can modulate and instruct the immune response, since these cells have been shown to produce and release several cytokines. Thus, we evaluated whether PMNs stimulated with Pb can modulate the immune response to a Th1 phenotype through the production of IFN-?, as well as the role of "pattern-recognition receptors" (PRRs) such as TLR2, TLR4 and Dectin-1 in this production. Furthermore, we asked whether activation of the cells with the cytokines IL-12, IL-15 and IL-18 could result in increased levels of this cytokine. Peripheral blood PMNs obtained from 20 healthy donors were nonactivated or activated with IL-12, IL-15 or IL-18 in different concentrations and challenged with strain 18 Pb (Pb18) for 2h, 4h, 12h, 24h and 48h and evaluated for IFN-? production, by ELISA. In other experiments, PMNs were treated with monoclonal antibodies anti-TLR2, TLR4 and Dectin-1, challenged with Pb and evaluated for IFN-? production. We found that Pb induces human PMNs to produce IFN-?, probably by binding to TLR4 and Dectin-1 receptors expressed by these cells. Moreover, IFN-? levels were significantly increased when cells were activated with each of the tested cytokines or a combination of two of them, being the association IL-12 plus IL-15 the most effective. The results support our hypothesis that during infection by Pb, human PMNs modulate the adaptive immune response to a Th1 response pattern, via IFN-? production. PMID:25022968

Rodrigues, Daniela Ramos; Fernandes, Reginaldo Keller; Balderramas, Helanderson de Almeida; Penitenti, Marcimara; Bachiega, Tatiana Fernanda; Calvi, Sueli Aparecida; Dias-Melicio, Luciane Alarcão; Ikoma, Maura Rosane Valério; Soares, Angela Maria Victoriano de Campos

2014-09-01

60

Anti-CD25 Treatment Depletes Treg Cells and Decreases Disease Severity in Susceptible and Resistant Mice Infected with Paracoccidioides brasiliensis  

PubMed Central

Regulatory T (Treg) cells are fundamental in the control of immunity and excessive tissue pathology. In paracoccidioidomycosis, an endemic mycosis of Latin America, the immunoregulatory mechanisms that control the progressive and regressive forms of this infection are poorly known. Due to its modulatory activity on Treg cells, we investigated the effects of anti-CD25 treatment over the course of pulmonary infection in resistant (A/J) and susceptible (B10.A) mice infected with Paracoccidioides brasiliensis. We verified that the resistant A/J mice developed higher numbers and more potent Treg cells than susceptible B10.A mice. Compared to B10.A cells, the CD4+CD25+Foxp3+ Treg cells of A/J mice expressed higher levels of CD25, CTLA4, GITR, Foxp3, LAP and intracellular IL-10 and TGF-?. In both resistant and susceptible mice, anti-CD25 treatment decreased the CD4+CD25+Foxp3+ Treg cell number, impaired indoleamine 2,3-dioxygenase expression and resulted in decreased fungal loads in the lungs, liver and spleen. In A/J mice, anti-CD25 treatment led to an early increase in T cell immunity, demonstrated by the augmented influx of activated CD4+ and CD8+ T cells, macrophages and dendritic cells to the lungs. At a later phase, the mild infection was associated with decreased inflammatory reactions and increased Th1/Th2/Th17 cytokine production. In B10.A mice, anti-CD25 treatment did not alter the inflammatory reactions but increased the fungicidal mechanisms and late secretion of Th1/Th2/Th17 cytokines. Importantly, in both mouse strains, the early depletion of CD25+ cells resulted in less severe tissue pathology and abolished the enhanced mortality observed in susceptible mice. In conclusion, this study is the first to demonstrate that anti-CD25 treatment is beneficial to the progressive and regressive forms of paracoccidioidomycosis, potentially due to the anti-CD25-mediated reduction of Treg cells, as these cells have suppressive effects on the early T cell response in resistant mice and the clearance mechanisms of fungal cells in susceptible mice.

Felonato, Maira; Pina, Adriana; de Araujo, Eliseu Frank; Loures, Flavio V.; Bazan, Silvia B.; Feriotti, Claudia; Calich, Vera L. G.

2012-01-01

61

Microplate alamarBlue assay for Paracoccidioides susceptibility testing.  

PubMed

CLSI method M27-A3 is not available for use with dimorphic fungi, such as those of the Paracoccidioides genus. In this study, we developed a microdilution method and added the alamarBlue reagent to test the responses of Paracoccidioides brasiliensis and Paracoccidioides lutzii against amphotericin B and itraconazole antifungals. The test proved to be sensitive, practical, and inexpensive and can be used to monitor the activity of low-growth microorganisms and their response to various drugs. PMID:23345296

de Paula e Silva, A C A; Oliveira, H C; Silva, J F; Sangalli-Leite, F; Scorzoni, L; Fusco-Almeida, A M; Mendes-Giannini, M J S

2013-04-01

62

Pseudozyma brasiliensis sp. nov., a xylanolytic, ustilaginomycetous yeast species isolated from an insect pest of sugarcane roots.  

PubMed

A novel ustilaginomycetous yeast isolated from the intestinal tract of an insect pest of sugarcane roots in Ribeirão Preto, São Paulo State, Brazil, represents a novel species of the genus Pseudozyma based on molecular analyses of the D1/D2 rDNA large subunit and the internal transcribed spacer (ITS1+ITS2) regions. The name Pseudozyma brasiliensis sp. nov. is proposed for this species, with GHG001(T) (?=?CBS 13268(T)?=?UFMG-CM-Y307(T)) as the type strain. P. brasiliensis sp. nov. is a sister species of Pseudozyma vetiver, originally isolated from leaves of vetiver grass and sugarcane in Thailand. P. brasiliensis sp. nov. is able to grow well with xylan as the sole carbon source and produces high levels of an endo-1,4-xylanase that has a higher specific activity in comparison with other eukaryotic xylanases. This enzyme has a variety of industrial applications, indicating the great biotechnological potential of P. brasiliensis. PMID:24682702

Oliveira, Juliana Velasco de Castro; Borges, Thuanny A; Corrêa dos Santos, Renato Augusto; Freitas, Larissa F D; Rosa, Carlos Augusto; Goldman, Gustavo Henrique; Riaño-Pachón, Diego Mauricio

2014-06-01

63

Polymorphism in the flanking regions of the PbGP43 gene from the human pathogen Paracoccidioides brasiliensis: search for protein binding sequences and poly(A) cleavage sites  

PubMed Central

Background Paracoccidioides brasiliensis is a thermo-dimorphic fungus that causes paracoccidiodomycosis (PCM). Glycoprotein gp43 is the fungal main diagnostic antigen, which can also protect against murine PCM and interact with extracellular matrix proteins. It is structurally related to glucanases, however not active, and whose expression varies considerably. We have presently studied polymorphisms in the PbGP43 flanking regions to help understand such variations. Results we tested the protein-binding capacity of oligonucleotides covering the PbGP43 proximal 5' flanking region, including overlap and mutated probes. We used electrophoretic mobility shift assays and found DNA binding regions between positions -134 to -103 and -255 to -215. Only mutation at -230, characteristic of P. brasiliensis phylogenetic species PS2, altered binding affinity. Next, we cloned and sequenced the 5' intergenic region up to position -2,047 from P. brasiliensis Pb339 and observed that it is composed of three tandem repetitive regions of about 500 bp preceded upstream by 442 bp. Correspondent PCR fragments of about 2,000 bp were found in eight out of fourteen isolates; in PS2 samples they were 1,500-bp long due to the absence of one repetitive region, as detected in Pb3. We also compared fifty-six PbGP43 3' UTR sequences from ten isolates and have not observed polymorphisms; however we detected two main poly(A) clusters (1,420 to 1,441 and 1,451 to 1,457) of multiple cleavage sites. In a single isolate we found one to seven sites. Conclusions We observed that the amount of PbGP43 transcripts accumulated in P. brasiliensis Pb339 grown in defined medium was about 1,000-fold higher than in Pb18 and 120-fold higher than in Pb3. We have described a series of features in the gene flanking regions and differences among isolates, including DNA-binding sequences, which might impact gene regulation. Little is known about regulatory sequences in thermo-dimorphic fungi. The peculiar structure of tandem repetitive fragments in the 5' intergenic region of PbGP43, their characteristic sequences, besides the presence of multiple poly(A) cleavage sites in the 3' UTR will certainly guide future studies.

2009-01-01

64

Genus Paracoccidioides: Species Recognition and Biogeographic Aspects  

PubMed Central

Background Paracoccidioidomycosis is a systemic mycosis caused by Paracoccidioides brasiliensis (species S1, PS2, PS3), and Paracoccidioides lutzii. This work aimed to differentiate species within the genus Paracoccidioides, without applying multilocus sequencing, as well as to obtain knowledge of the possible speciation processes. Methodology/Principal Findings Single nucleotide polymorphism analysis on GP43, ARF and PRP8 intein genes successfully distinguished isolates into four different species. Morphological evaluation indicated that elongated conidia were observed exclusively in P. lutzii isolates, while all other species (S1, PS2 and PS3) were indistinguishable. To evaluate the biogeographic events that led to the current geographic distribution of Paracoccidioides species and their sister species, Nested Clade and Likelihood Analysis of Geographic Range Evolution (LAGRANGE) analyses were applied. The radiation of Paracoccidioides started in northwest South America, around 11–32 million years ago, as calculated on the basis of ARF substitution rate, in the BEAST program. Vicariance was responsible for the divergence among S1, PS2 and P. lutzii and a recent dispersal generated the PS3 species, restricted to Colombia. Taking into account the ancestral areas revealed by the LAGRANGE analysis and the major geographic distribution of L. loboi in the Amazon basin, a region strongly affected by the Andes uplift and marine incursions in the Cenozoic era, we also speculate about the effect of these geological events on the vicariance between Paracoccidioides and L. loboi. Conclusions/Significance The use of at least 3 SNPs, but not morphological criteria, as markers allows us to distinguish among the four cryptic species of the genus Paracoccidioides. The work also presents a biogeographic study speculating on how these species might have diverged in South America, thus contributing to elucidating evolutionary aspects of the genus Paracoccidioides.

Theodoro, Raquel Cordeiro; Teixeira, Marcus de Melo; Felipe, Maria Sueli Soares; Paduan, Karina dos Santos; Ribolla, Paulo Martins; San-Blas, Gioconda; Bagagli, Eduardo

2012-01-01

65

P. brasiliensis Virulence Is Affected by SconC, the Negative Regulator of Inorganic Sulfur Assimilation  

PubMed Central

Conidia/mycelium-to-yeast transition of Paracoccidioidesbrasiliensis is a critical step for the establishment of paracoccidioidomycosis, a systemic mycosis endemic in Latin America. Thus, knowledge of the factors that mediate this transition is of major importance for the design of intervention strategies. So far, the only known pre-requisites for the accomplishment of the morphological transition are the temperature shift to 37°C and the availability of organic sulfur compounds. In this study, we investigated the auxotrophic nature to organic sulfur of the yeast phase of Paracoccidioides, with special attention to P. brasiliensis species. For this, we addressed the role of SconCp, the negative regulator of the inorganic sulfur assimilation pathway, in the dimorphism and virulence of this pathogen. We show that down-regulation of SCONC allows initial steps of mycelium-to-yeast transition in the absence of organic sulfur compounds, contrarily to the wild-type fungus that cannot undergo mycelium-to-yeast transition under such conditions. However, SCONC down-regulated transformants were unable to sustain yeast growth using inorganic sulfur compounds only. Moreover, pulses with inorganic sulfur in SCONC down-regulated transformants triggered an increase of the inorganic sulfur metabolism, which culminated in a drastic reduction of the ATP and NADPH cellular levels and in higher oxidative stress. Importantly, the down-regulation of SCONC resulted in a decreased virulence of P. brasiliensis, as validated in an in vivo model of infection. Overall, our findings shed light on the inability of P. brasiliensis yeast to rely on inorganic sulfur compounds, correlating its metabolism with cellular energy and redox imbalances. Furthermore, the data herein presented reveal SconCp as a novel virulence determinant of P. brasiliensis.

Menino, Joao Filipe; Saraiva, Margarida; Gomes-Rezende, Jessica; Sturme, Mark; Pedrosa, Jorge; Castro, Antonio Gil; Ludovico, Paula; Goldman, Gustavo H.; Rodrigues, Fernando

2013-01-01

66

Serology of Paracoccidioidomycosis Due to Paracoccidioides lutzii  

PubMed Central

Paracoccidioides lutzii is a new agent of paracoccidioidomycosis (PCM) and has its epicenter localized to the Central-West region of Brazil. Serological diagnosis of PCM caused by P. lutzii has not been established. This study aimed to develop new antigenic preparations from P. lutzii and to apply them in serological techniques to improve the diagnosis of PCM due to P. lutzii. Paracoccidioides lutzii exoantigens, cell free antigen (CFA), and a TCA-precipitated antigen were evaluated in immunodiffusion (ID) tests using a total of 89 patient sera from the Central-West region of Brazil. Seventy-two sera were defined as reactive for P. brasiliensis using traditional antigens (AgPbB339 and gp43). Non-reactive sera for traditional antigens (n?=?17) were tested with different P. lutzii preparations and P. lutzii CFA showed 100% reactivity. ELISA was found to be a very useful test to titer anti-P. lutzii antibodies using P. lutzii-CFA preparations. Sera from patients with PCM due to P. lutzii presented with higher antibody titers than PCM due to P. brasiliensis and heterologous sera. In western blot, sera from patients with PCM due to P. lutzii were able to recognize antigenic molecules from the P. lutzii-CFA antigen, but sera from patients with PCM due to P. brasiliensis could not recognize any P. lutzii molecules. Due to the facility of preparing P. lutzii CFA antigens we recommend its use in immunodiffusion tests for the diagnosis of PCM due to P. lutzii. ELISA and western blot can be used as complementary tests.

Gegembauer, Gregory; Araujo, Leticia Mendes; Pereira, Edy Firmina; Rodrigues, Anderson Messias; Paniago, Anamaria Mello Miranda; Hahn, Rosane Christine; de Camargo, Zoilo Pires

2014-01-01

67

Occurrence of Paracoccidioides lutzii in the Amazon Region: Description of Two Cases  

PubMed Central

Paracoccidioidomycosis (PCM), the most important human systemic mycosis in Latin America, is known to be caused by at least four different phylogenetic lineages within the Paracoccidioides brasiliensis complex, including S1, PS2, PS3, and Pb01-like group. Herein, we describe two cases of PCM in patients native from the Amazon region. The disease was originally thought to have been caused by P. brasiliensis. Despite the severity of the cases, sera from the patients were negative in immunodiffusion tests using the standard exoantigen from P. brasiliensis B-339. However, a positive response was recorded with an autologous preparation of Paracoccidioides lutzii exoantigen. A phylogenetic approach based on the gp43 and ARF loci revealed high similarity between our clinical isolates and the Pb01-like group. The occurrence of PCM caused by P. lutzii in the Brazilian Amazon (Pará State) was thus proven. The incidence of PCM caused by P. lutzii may be underestimated in northern Brazil.

Marques-da-Silva, Silvia Helena; Messias Rodrigues, Anderson; de Hoog, G. Sybren; Silveira-Gomes, Fabiola; Pires de Camargo, Zoilo

2012-01-01

68

Transcriptional profile of Paracoccidioides spp. in response to itraconazole  

PubMed Central

Background Itraconazole is currently used to treat paracoccidioidomycosis. The mechanism of action of azoles has been elucidated in some fungi, although little is known regarding its mechanism of action in Paracoccidioides spp. The present work focused on identification of regulated transcripts using representational difference analysis of Paracoccidioides spp. yeast cells treated with itraconazole for 1 and 2 h. Results Paracoccidioides Pb01 genes up-regulated by itraconazole included genes involved in cellular transport, metabolism/energy, transcription, cell rescue, defense and virulence. ERG11, ERG6, ERG3, ERG5 and ERG25 were up-regulated at multiple time points. In vivo infection experiments in mice corroborated the in vitro results. Ergosterol levels and distribution were evaluated in Paracoccidioides Pb18 yeast cells, and the results demonstrate that both factors were changed in the fungus treated with itraconazole. Conclusion To our knowledge, this is the first transcriptional analysis of Paracoccidioides spp. exposed to a triazole drug. Here acetyl seems to be intensively produced from different metabolic pathways to produce ergosterol by the action of ergosterol synthesis related enzymes, which were also affected in other fungi. Among the genes affected, we identified genes in common with other fungi, as well as genes unique to Paracoccidioides Pb01. Those genes could be considered target to new drugs. Voltage-gated Ca2+ alpha subunit (CAV), Tetracycline resistance protein (TETA) and Hemolisyn-iii channel protein (HLYiii) were found only here and a probably involvement with resistence to itraconazole could be investigated in the future. However our findings do not permit inference to current clinical practice.

2014-01-01

69

Intermolecular interactions of the malate synthase of Paracoccidioides spp  

PubMed Central

Background The fungus Paracoccidioides spp is the agent of paracoccidioidomycosis (PCM), a pulmonary mycosis acquired by the inhalation of fungal propagules. Paracoccidioides malate synthase (PbMLS) is important in the infectious process of Paracoccidioides spp because the transcript is up-regulated during the transition from mycelium to yeast and in yeast cells during phagocytosis by murine macrophages. In addition, PbMLS acts as an adhesin in Paracoccidioides spp. The evidence for the multifunctionality of PbMLS indicates that it could interact with other proteins from the fungus and host. The objective of this study was to identify and analyze proteins that possibly bind to PbMLS (PbMLS-interacting proteins) because protein interactions are intrinsic to cell processes, and it might be possible to infer the function of a protein through the identification of its ligands. Results The search for interactions was performed using an in vivo assay with a two-hybrid library constructed in S. cerevisiae; the transcripts were sequenced and identified. In addition, an in vitro assay using pull-down GST methodology with different protein extracts (yeast, mycelium, yeast-secreted proteins and macrophage) was performed, and the resulting interactions were identified by mass spectrometry (MS). Some of the protein interactions were confirmed by Far-Western blotting using specific antibodies, and the interaction of PbMLS with macrophages was validated by indirect immunofluorescence and confocal microscopy. In silico analysis using molecular modeling, dynamics and docking identified the amino acids that were involved in the interactions between PbMLS and PbMLS-interacting proteins. Finally, the interactions were visualized graphically using Osprey software. Conclusion These observations indicate that PbMLS interacts with proteins that are in different functional categories, such as cellular transport, protein biosynthesis, modification and degradation of proteins and signal transduction. These data suggest that PbMLS could play different roles in the fungal cell.

2013-01-01

70

EXPERIMENTAL PULMONARY FIBROSIS INDUCED BYPARACOCCIDIOIDES BRASILIENSIS CONIDIA: MEASUREMENT OF LOCAL HOST RESPONSES  

Microsoft Academic Search

Pulmonary fibrosis was induced following inoculation of Paracoccidioides brasiliensis conidia intra- nasally in BALB\\/c mice. Fibrosis was associated with formation of granulomas, increase in lung hydroxyproline, and sustained increases in tissue tumor necrosis factor- a and transforming growth factor-b. This study suggests a role for these cytokines in generation of pulmonary fibrosis associated with chronic granulomatous infectious diseases. Fibrosis is

L. FRANCO; L. NAJVAR; B. L. GOMEZ; S. RESTREPO; J. R. GRAYBILL; A. RESTREPO

1998-01-01

71

Serological and antigenic profiles of clinical isolates of Paracoccidioides spp. from Central Western Brazil.  

PubMed

Clinical Paracoccidioides spp. isolates from patients with paracoccidioidomycosis (PCM) in Mato Grosso, Brazil exhibit different patterns of serologic reactivity. The results observed for reactions of radial immunodiffusion against the commonly used exoantigens containing a 43-kDa glycoprotein (gp43) suggest that this fungus exhibits major antigenic variability by geographic region. There is a phylogenetic gap between Paracoccidioides spp. isolates among different regions of Latin America. In particular, those from the central region of Brazil (i.e. Mato Grosso state) exhibit a lower rate of genetic similarity. We aimed at investigating the phylogenetic classification of clinical isolates of Paracoccidioides spp. in Central Brazil and the different antigenic profiles that produce. Exoantigens were obtained from five clinical isolates: two P. brasiliensis (Pb166 and Pb2880) and three P. lutzii (PL2875, PL9840, and PL2912). The protein/glycoprotein profiles of P. lutzii exoantigens were different from each other. Isolate PL9840 exhibited the most distinct bands, and isolates PL2875 and PL2912 exhibited more diffuse bands and a very intense band between 50 and 60 kDa. P. brasiliensis isolates had similar protein profiles, exhibiting a low-intensity band at 220 kDa and a diffuse band between 50 and 60 kDa. P. lutzii isolates exhibit high species-specific antigen variability, which we have already been assessed in proteomic studies. PMID:24635832

Queiroz Júnior, Luiz de Pádua; de Camargo, Zoilo Pires; Tadano, Tomoko; Rodrigues, Anderson Messias; Takarara, Doracilde Terumi; Gegembauer, Gregory; Araujo, Leticia Mendes; Hahn, Rosane Christine

2014-08-01

72

Spathaspora brasiliensis sp. nov., Spathaspora suhii sp. nov., Spathaspora roraimanensis sp. nov. and Spathaspora xylofermentans sp. nov., four novel (D)-xylose-fermenting yeast species from Brazilian Amazonian forest.  

PubMed

Four new D-xylose fermenting yeast species of the clade Spathaspora were recovered from rotting-wood samples in a region of Amazonian forest, Northern Brazil. Three species produced unconjugated asci with a single elongated ascospore with curved ends. These species are described as Spathaspora brasiliensis, Spathaspora suhii and Spathaspora roraimanensis. Two isolates of an asexually reproducing species belonging to the Spathaspora clade were also obtained and they are described as Spathaspora xylofermentans. All these species are able to ferment D-xylose during aerobic batch growth in rich YP (1 % yeast extract, 2 % peptone and 2 % D-xylose) medium, albeit with differing efficiencies. The type strains are Spathaspora brasiliensis sp. nov UFMG-HMD19.3 (=CBMAI 1425=CBS 12679), Spathaspora suhii sp. nov. UFMG-XMD16.2 (=CBMAI 1426=CBS 12680), Spathaspora roraimanensis sp. nov. UFMG-XMD23.2 (CBMAI 1427=CBS 12681) and Spathaspora xylofermentans sp. nov. UFMG-HMD23.3 (=CBMAI 1428=CBS 12682). PMID:23053696

Cadete, Raquel M; Melo, Monaliza A; Zilli, Jerri E; Vital, Marcos J S; Mouro, Adriane; Prompt, Alice H; Gomes, Fátima C O; Stambuk, Boris U; Lachance, Marc-André; Rosa, Carlos A

2013-02-01

73

Comparative proteomics in the genus Paracoccidioides.  

PubMed

The genus Paracoccidioides comprises a complex of phylogenetic species of dimorphic pathogenic fungi, the etiologic agents of paracoccidioidomycosis (PCM), a disease confined to Latin America and of marked relevance in its endemic areas due to its high frequency and severity. The members of the Paracoccidioides genus are distributed in distinct phylogenetic species (S1, PS2, PS3 and 01-like) that potentially differ in their biochemical and molecular characteristics. In this work, we performed the proteomic characterization of different members of the genus Paracoccidioides. We compared the proteomic profiles of Pb01 (01-like), Pb2 (PS2), Pb339 (S1) and PbEPM83 (PS3) using 2D electrophoresis and mass spectrometry. The proteins/isoforms were selected based on the staining intensity of the spots as determined by image analysis. The proteins/isoforms were in-gel digested and identified by peptide mass fingerprinting and ion fragmentation. A total of 714 spots were detected, of which 343 were analyzed. From these spots, 301 represented differentially expressed proteins/isoforms among the four analyzed isolates, as determined by ANOVA. After applying the FDR correction, a total of 267 spots were determined to be differentially expressed. From the total, 193 proteins/isoforms were identified by PMF and confirmed by ion fragmentation. Comparing the expression profiles of the isolates, the proteins/isoforms that were related to glycolysis/gluconeogenesis and to alcohol fermentation were more abundant in Pb01 than in other representatives of the genus Paracoccidioides, indicating ahigher use of anaerobic pathways for energy production. Those enzymes related to the oxidative stress response were more abundant in Pb01, Pb2 and Pb339, indicating a better response to ROS in these members of the Paracoccidioides complex. The enzymes of the pentose phosphate pathway were abundant in Pb2. Antigenic proteins, such as GP43 and a 27-kDa antigenic protein, were less abundant in Pb01 and Pb2. The proteomic profile indicates metabolic differences among the analyzed members of the Paracoccidioides genus. PMID:23911955

Pigosso, Laurine Lacerda; Parente, Ana Flávia Alves; Coelho, Alexandre Siqueira Guedes; Silva, Luciano Paulino; Borges, Clayton Luiz; Bailão, Alexandre Melo; Soares, Célia Maria de Almeida

2013-11-01

74

Transcriptional profile of Paracoccidioides induced by oenothein B, a potential antifungal agent from the Brazilian Cerrado plant Eugenia uniflora  

PubMed Central

Background The compound oenothein B (OenB), which is isolated from the leaves of Eugenia uniflora, a Brazilian Cerrado plant, interferes with Paracoccidioides yeast cell morphology and inhibits 1,3-?-D-glucan synthase (PbFKS1) transcript accumulation, which is involved in cell wall synthesis. In this work we examined the gene expression changes in Paracoccidioides yeast cells following OenB treatment in order to investigate the adaptive cellular responses to drug stress. Results We constructed differential gene expression libraries using Representational Difference Analysis (RDA) of Paracoccidioides yeast cells treated with OenB for 90 and 180 min. Treatment for 90 min resulted in the identification of 463 up-regulated expressed sequences tags (ESTs) and 104 down-regulated ESTs. For the 180 min treatment 301 up-regulated ESTs and 143 down-regulated were identified. Genes involved in the cell wall biosynthesis, such as GLN1, KRE6 and FKS1, were found to be regulated by OenB. Infection experiments in macrophages corroborated the in vitro results. Fluorescence microscopy showed increased levels of chitin in cells treated with OenB. The carbohydrate polymer content of the cell wall of the fungus was also evaluated, and the results corroborated with the transcriptional data. Several other genes, such as those involved in a variety of important cellular processes (i.e., membrane maintenance, stress and virulence) were found to be up-regulated in response to OenB treatment. Conclusions The exposure of Paracoccidioides to OenB resulted in a complex altered gene expression profile. Some of the changes may represent specific adaptive responses to this compound in this important pathogenic fungus.

2013-01-01

75

Inhibition of paracoccidioides lutzii Pb01 isocitrate lyase by the natural compound argentilactone and its semi-synthetic derivatives.  

PubMed

The dimorphic fungus Paracoccidioides spp. is responsible for paracoccidioidomycosis, the most prevalent systemic mycosis in Latin America, causing serious public health problems. Adequate treatment of mycotic infections is difficult, since fungi are eukaryotic organisms with a structure and metabolism similar to those of eukaryotic hosts. In this way, specific fungus targets have become important to search of new antifungal compound. The role of the glyoxylate cycle and its enzymes in microbial virulence has been reported in many fungal pathogens, including Paracoccidioides spp. Here, we show the action of argentilactone and its semi-synthetic derivative reduced argentilactone on recombinant and native isocitrate lyase from Paracoccidioides lutzii Pb01 (PbICL) in the presence of different carbon sources, acetate and glucose. Additionally, argentilactone and its semi-synthetic derivative reduced argentilactone exhibited relevant inhibitory activity against P. lutzii Pb01 yeast cells and dose-dependently influenced the transition from the mycelium to yeast phase. The other oxygenated derivatives tested, epoxy argentilactone and diol argentilactone-, did not show inhibitory action on the fungus. The results were supported by in silico experiments. PMID:24752170

Prado, Renata Silva do; Alves, Ricardo Justino; Oliveira, Cecília Maria Alves de; Kato, Lucília; Silva, Roosevelt Alves da; Quintino, Guilherme Oliveira; do Desterro Cunha, Silvio; de Almeida Soares, Célia Maria; Pereira, Maristela

2014-01-01

76

Melanin as a virulence factor of Paracoccidioides brasiliensis and other dimorphic pathogenic fungi: a minireview  

Microsoft Academic Search

Melanin pigments are substances produced by a broad variety of pathogenic microorganisms, including bacteria, fungi, and helminths.\\u000a Microbes predominantly produce melanin pigment via tyrosinases, laccases, catecholases, and the polyketide synthase pathway.\\u000a In fungi, melanin is deposited in the cell wall and cytoplasm, and melanin particles (“ghosts”) can be isolated from these\\u000a fungi that have the same size and shape of

Carlos P. Taborda; Marcelo B. da Silva; Joshua D. Nosanchuk; Luiz R. Travassos

2008-01-01

77

Cell cycle, DNA replication, repair, and recombination in the dimorphic human pathogenic fungus Paracoccidioides brasiliensis  

Microsoft Academic Search

DNA replication, together with repair mechanisms and cell cycle control, are the most important cellular processes necessary to maintain correct transfer of genetic information to the progeny. These processes are well conserved throughout the Eukarya, and the genes that are involved provide essential information for understanding the life cycle of an organism. We used computational tools for data mining of

Viviane Castelo Branco Reis; Fernando Araripe; Gonçalves Torres; Marcio José Poças-Fonseca; Marlene Teixeira De-Souza; Diorge Paulo de Souza; João Ricardo Moreira Almeida; Camila Marinho-Silva; Nádia Skorupa Parachin; Alessandra da Silva Dantas; Thiago Machado Mello-de-Sousa; Lídia Maria Pepe de Moraes

2005-01-01

78

Hemoglobin uptake by Paracoccidioides spp. is receptor-mediated.  

PubMed

Iron is essential for the proliferation of fungal pathogens during infection. The availability of iron is limited due to its association with host proteins. Fungal pathogens have evolved different mechanisms to acquire iron from host; however, little is known regarding how Paracoccidioides species incorporate and metabolize this ion. In this work, host iron sources that are used by Paracoccidioides spp. were investigated. Robust fungal growth in the presence of the iron-containing molecules hemin and hemoglobin was observed. Paracoccidioides spp. present hemolytic activity and have the ability to internalize a protoporphyrin ring. Using real-time PCR and nanoUPLC-MSE proteomic approaches, fungal growth in the presence of hemoglobin was shown to result in the positive regulation of transcripts that encode putative hemoglobin receptors, in addition to the induction of proteins that are required for amino acid metabolism and vacuolar protein degradation. In fact, one hemoglobin receptor ortholog, Rbt5, was identified as a surface GPI-anchored protein that recognized hemin, protoporphyrin and hemoglobin in vitro. Antisense RNA technology and Agrobacterium tumefaciens-mediated transformation were used to generate mitotically stable Pbrbt5 mutants. The knockdown strain had a lower survival inside macrophages and in mouse spleen when compared with the parental strain, which suggested that Rbt5 could act as a virulence factor. In summary, our data indicate that Paracoccidioides spp. can use hemoglobin as an iron source most likely through receptor-mediated pathways that might be relevant for pathogenic mechanisms. PMID:24831516

Bailão, Elisa Flávia Luiz Cardoso; Parente, Juliana Alves; Pigosso, Laurine Lacerda; de Castro, Kelly Pacheco; Fonseca, Fernanda Lopes; Silva-Bailão, Mirelle Garcia; Báo, Sônia Nair; Bailão, Alexandre Melo; Rodrigues, Marcio L; Hernandez, Orville; McEwen, Juan G; Soares, Célia Maria de Almeida

2014-05-01

79

Hemoglobin Uptake by Paracoccidioides spp. Is Receptor-Mediated  

PubMed Central

Iron is essential for the proliferation of fungal pathogens during infection. The availability of iron is limited due to its association with host proteins. Fungal pathogens have evolved different mechanisms to acquire iron from host; however, little is known regarding how Paracoccidioides species incorporate and metabolize this ion. In this work, host iron sources that are used by Paracoccidioides spp. were investigated. Robust fungal growth in the presence of the iron-containing molecules hemin and hemoglobin was observed. Paracoccidioides spp. present hemolytic activity and have the ability to internalize a protoporphyrin ring. Using real-time PCR and nanoUPLC-MSE proteomic approaches, fungal growth in the presence of hemoglobin was shown to result in the positive regulation of transcripts that encode putative hemoglobin receptors, in addition to the induction of proteins that are required for amino acid metabolism and vacuolar protein degradation. In fact, one hemoglobin receptor ortholog, Rbt5, was identified as a surface GPI-anchored protein that recognized hemin, protoporphyrin and hemoglobin in vitro. Antisense RNA technology and Agrobacterium tumefaciens-mediated transformation were used to generate mitotically stable Pbrbt5 mutants. The knockdown strain had a lower survival inside macrophages and in mouse spleen when compared with the parental strain, which suggested that Rbt5 could act as a virulence factor. In summary, our data indicate that Paracoccidioides spp. can use hemoglobin as an iron source most likely through receptor-mediated pathways that might be relevant for pathogenic mechanisms.

Bailao, Elisa Flavia Luiz Cardoso; Parente, Juliana Alves; Pigosso, Laurine Lacerda; de Castro, Kelly Pacheco; Fonseca, Fernanda Lopes; Silva-Bailao, Mirelle Garcia; Bao, Sonia Nair; Bailao, Alexandre Melo; Rodrigues, Marcio L.; Hernandez, Orville; McEwen, Juan G.; Soares, Celia Maria de Almeida

2014-01-01

80

Transcriptional and Proteomic Responses to Carbon Starvation in Paracoccidioides  

PubMed Central

Background The genus Paracoccidioides comprises human thermal dimorphic fungi, which cause paracoccidioidomycosis (PCM), an important mycosis in Latin America. Adaptation to environmental conditions is key to fungal survival during human host infection. The adaptability of carbon metabolism is a vital fitness attribute during pathogenesis. Methodology/Principal Findings The fungal pathogen Paracoccidioides spp. is exposed to numerous adverse conditions, such as nutrient deprivation, in the human host. In this study, a comprehensive response of Paracoccidioides, Pb01, under carbon starvation was investigated using high-resolution transcriptomic (RNAseq) and proteomic (NanoUPLC-MSE) approaches. A total of 1,063 transcripts and 421 proteins were differentially regulated, providing a global view of metabolic reprogramming during carbon starvation. The main changes were those related to cells shifting to gluconeogenesis and ethanol production, supported by the degradation of amino acids and fatty acids and by the modulation of the glyoxylate and tricarboxylic cycles. This proposed carbon flow hypothesis was supported by gene and protein expression profiles assessed using qRT-PCR and western blot analysis, respectively, as well as using enzymatic, cell dry weight and fungus-macrophage interaction assays. The carbon source provides a survival advantage to Paracoccidioides inside macrophages. Conclusions/Significance For a complete understanding of the physiological processes in an organism, the integration of approaches addressing different levels of regulation is important. To the best of our knowledge, this report presents the first description of the responses of Paracoccidioides spp. to host-like conditions using large-scale expression approaches. The alternative metabolic pathways that could be adopted by the organism during carbon starvation can be important for a better understanding of the fungal adaptation to the host, because systems for detecting and responding to carbon sources play a major role in adaptation and persistence in the host niche.

Lima, Patricia de Sousa; Casaletti, Luciana; Bailao, Alexandre Melo; de Vasconcelos, Ana Tereza Ribeiro; Fernandes, Gabriel da Rocha; Soares, Celia Maria de Almeida

2014-01-01

81

Factors associated with Paracoccidiodes brasiliensis infection among permanent residents of three endemic areas in Colombia.  

PubMed Central

The natural habitat of Paracoccidioides brasiliensis, the aetiologic agent of paracoccidioidomycosis, has not been determined. Consequently, the events leading to the acquisition of infection remain controversial. To identify factors associated with infection in endemic areas we conducted a survey in three rural communities in Colombia where we had previously diagnosed paracoccidioidomycosis in children. Permanent residents were surveyed taking into consideration environmental and occupational variables. Skin tests were used to classify subjects as infected or non-infected. Variables found associated with infection were: (i) community A: previous residence around Porce river and agriculture in vegetable gardens; (ii) community C: frequent use of specific water sources; (iii) community V: housekeeping activities, and (iv) total group: age > 25 years and contact with bats. Residents in communities with higher prevalence of infection were older, had more complex residence history, and referred more contact with armadillos than residents of communities with lower infection.

Cadavid, D.; Restrepo, A.

1993-01-01

82

Detection of 2 immunoreactive antigens in the cell wall of Sporothrix brasiliensis and Sporothrix globosa.  

PubMed

The cell wall of members of the Sporothrix schenckii complex contains highly antigenic molecules which are potentially useful for the diagnosis and treatment of sporotrichosis. In this study, 2 immunoreactive antigens of 60 (Gp60) and 70 kDa (Gp70) were detected in the cell wall of the yeast morphotypes of Sporothrix brasiliensis and Sporothrix globosa. PMID:24827145

Ruiz-Baca, Estela; Hernández-Mendoza, Gustavo; Cuéllar-Cruz, Mayra; Toriello, Conchita; López-Romero, Everardo; Gutiérrez-Sánchez, Gerardo

2014-07-01

83

Galleria mellonella as a model host to study Paracoccidioides lutzii and Histoplasma capsulatum  

PubMed Central

Non-mammalian models have been used to investigate fungal virulence. In this work we have explored the use of Galleria mellonella as an infection model for the pathogenic dimorphic fungi Histoplasma capsulatum and Paracoccidioides lutzii. In mammalian models these fungi cause similar infections, and disease outcomes are influenced by the quantity of the infective inocula. We describe a similar aspect in a G. mellonella model and characterize the pathogenesis features in this system. Infection with P. lutzii or H. capsulatum, in all inoculum used, killed larvae at 25 and 37°C. However, there was a lack of correlation between the number of yeast cells used for infection and the time to larvae death, which may indicate that the fungi induce protective responses in a dynamic manner as the lowest concentrations of fungi induced the most rapid death. For both fungi, the degree of larvae melanization was directly proportional to the inocula size, and this effect was visibly more apparent at 37°C. Histological evaluation of the larvae showed a correlation between the inoculum and granuloma-like formation. Our results suggest that G. mellonella is a potentially useful model to study virulence of dimorphic fungi.

Thomaz, Luciana; Garcia-Rodas, Rocio; Guimaraes, Allan J.; Taborda, Carlos P.; Zaragoza, Oscar; Nosanchuk, Joshua D.

2013-01-01

84

Hydroxynitrile lyase from Hevea brasiliensis: molecular characterization and mechanism of enzyme catalysis.  

PubMed

(S)-Hydroxynitrile lyase (Hnl) from the tropical rubber tree Hevea brasiliensis is a 29 kDa single chain protein that catalyses the breakdown or formation of a C--C bond by reversible addition of hydrocyanic acid to aldehydes or ketones. The primary sequence of Hnl has no significant homology to known proteins. Detailed homology investigations employing PROFILESEARCH and secondary structure prediction algorithms suggest that Hnl is a member of the alpha/beta hydrolase fold protein family and contains a catalytic triad as functional residues for catalysis. The significance of predicted catalytic residues was tested and confirmed by site-directed mutagenesis and expression of mutant and wild-type proteins in the yeast, Saccharomyces cerevisiae. Based on these data we suggest a mechanistic model for the (S)-cyanohydrin synthesis catalyzed by hydroxynitrile lyase from Hevea brasiliensis. PMID:9094745

Hasslacher, M; Kratky, C; Griengl, H; Schwab, H; Kohlwein, S D

1997-03-01

85

Characterization of HbWRKY1, a WRKY transcription factor from Hevea brasiliensis that negatively regulates HbSRPP.  

PubMed

Small rubber particle protein (SRPP) is a major component of Hevea brasiliensis (H. brasiliensis) latex, which is involved in natural rubber (NR) biosynthesis. However, little information is available on the regulation of SRPP gene (HbSRPP) expression. To study the transcriptional regulation of HbSRPP, the yeast one-hybrid experiment was performed to screen the latex cDNA library using the HbSRPP promoter as bait. One cDNA that encodes the WRKY transcription factor, designated as HbWRKY1, was isolated from H. brasiliensis. HbWRKY1 contains a 1437 bp open reading frame that encodes 478 amino acids. The deduced HbWRKY1 protein was predicted to possess two conserved WRKY domains and a C2H2 zinc-finger motif. HbWRKY1 was expressed at different levels, with the highest transcription in the flower, followed by the bark, latex, and leaf. Furthermore, the co-expression of pHbSRP::GUS with CaMV35S::HbWRKY1 significantly decreased the GUS activity in transgenic tobacco, indicating that HbWRKY1 significantly suppressed the HbSRPP promoter. These results suggested that HbWRKY1 maybe a negative transcription regulator of HbSRPP involved in NR biosynthesis in H. brasiliensis. PMID:23988297

Wang, Ying; Guo, Dong; Li, Hui-Liang; Peng, Shi-Qing

2013-10-01

86

Nocardia brasiliensis-associated femorotibial osteomyelitis.  

PubMed

We report a case of femorotibial osteomyelitis due to Nocardia brasiliensis. Nocardia spp are a rare cause of bone infections, and the majority of such cases are associated with the spine. This type of osteomyelitis is uncommon, and in the immunocompetent host, is more often related to a chronic evolution following direct inoculation of the microorganism. PMID:24362018

Vanegas, Samuel; Franco-Cendejas, Rafael; Cicero, Antonio; López-Jácome, Esaú; Colin, Claudia; Hernández, Melissa

2014-03-01

87

Antioxidant Activity of Agaricus brasiliensis Basidiocarps on Different Maturation Phases.  

PubMed

Different maturation phases of basidiocarp could affect the bioactivity and concentration of some active substances. A. brasiliensis Wasser et al. (A. blazei Murrill) has shown antitumor activity that could be related to the antioxidant activity. However there is no information of the best basidiocarp maturation phase for extracting antioxidant substances in order to determine the moment of harvesting in mushroom cultivation. The objective of this work was to evaluate the antioxidant activity of A. brasiliensis strains on different basidiocarp maturation phases. The best condition for extraction of A. brasiliensis antioxidants is with methanol as solvent at 60 °C for 60 min. Strains with closed basidiocarp have higher antioxidant activity than with opened basidiocarp. Antioxidant activity varies in each strain. It was concluded that A. brasiliensis is a natural source of antioxidant compounds. Also there is higher antioxidant activity in closed than opened caps and consequently higher functional activity. It reinforces the synergic action among different A. brasiliensis compounds as a functional food and the importance of further investigation for isolation and characterization of antioxidant substances of A. brasiliensis. It also determines the best harvest period in order to obtain the highest antioxidant activity from basidiocarp. PMID:24031621

Mourão, Francielly; Harue Umeo, Suzana; Seiko Takemura, Orlando; Andrea Linde, Giani; Barros Colauto, Nelson

2011-01-01

88

Susceptibility of species within the Sporothrix schenckii complex to a panel of killer yeasts.  

PubMed

The Sporothrix schenckii complex is the etiologic agent of sporotrichosis, a subacute or chronic mycosis which can affect humans and animals. Killer yeasts have been used in the medical field for development of novel antimycotics and biotyping of pathogenic fungi. The action of 18 killer yeasts on the growth of 88 characterized S. schenckii, Sporothrix globosa, Sporothrix brasiliensis, and Sporothrix mexicana clinical and environmental isolates was evaluated. Killer studies were performed on Petri dishes containing cheese black starch agar. The yeasts Candida catenulata (QU26, QU31, QU127, LV102); Trichosporon faecale (QU100); Trichosporon japonicum (QU139); Kluyveromyces lactis (QU30, QU99, QU73); Kazachstania unispora (QU49), Trichosporon insectorum (QU89), and Kluyveromyces marxianus (QU103) showed activity against all strains of the S. schenckii complex tested. Observation by optical microscopy of S. brasiliensis 61 within the inhibition haloes around the colonies of the killer yeasts QU100, QU139, and LV102 showed that there was no conidiation, but there was hyphal proliferation. The toxins were fungistatic against S. brasiliensis 61. There was no difference in susceptibility to the toxins among the S. schenckii species complex. Further investigations are necessary to clearly establish the mechanism of action of the toxins. PMID:23686831

Stopiglia, Cheila Denise Ottonelli; Heidrich, Daiane; Sorrentino, Julia Medeiros; Vieira, Fabiane Jamono; Landell, Melissa Fontes; Valente, Patrícia; Scroferneker, Maria Lúcia

2014-06-01

89

Red yeast  

MedlinePLUS

... with this combination.Talk with your health provider.Cyclosporine (Neoral, Sandimmune)Red yeast might affect the muscles. Cyclosporine (Neoral, Sandimmune) might also affect the muscles. Taking ...

90

Yeast Infections  

MedlinePLUS

Candida is the scientific name for yeast. It is a fungus that lives almost everywhere, including in ... infection that causes white patches in your mouth Candida esophagitis is thrush that spreads to your esophagus, ...

91

Counting Yeast.  

ERIC Educational Resources Information Center

Describes changes to a traditional study of population in yeast colonies. Changes to the procedures include: (1) only one culture per student team; (2) cultures are inoculated only once; and (3) the same tube is sampled daily. (DDR)

Bealer, Jonathan; Welton, Briana

1998-01-01

92

Antineoplasic activity of Agaricus brasiliensis basidiocarps on different maturation phases  

PubMed Central

The fungus Agaricus brasiliensis is a Basidiomycete studied because of its immunomodulation and/or antitumor substances. The objective of this study was to verify the Agaricus brasiliensis antineoplasic activity in vivo on different basidiocarp maturation phases on Sarcoma 180 cells implanted in mice. Sarcoma cells were implanted in mice and after seven days mice were divided in three groups. The first group was treated with saline solution, the second group was treated with closed basidiocarp extract solution and the third group was treated with opened basidiocarp extract solution. After 30 days of being daily orally treated with these three solutions all animals suffered euthanasia, and the splenic index, tumor mass and volume were determined. No significant differences of the tumor growth inhibition in function of the different basidiocarp maturation phases for the Agaricus brasiliensis strain were observed. The in vivo basidiocarp antineoplasic average activity was 89.22%.

Mourao, Francielly; Linde, Giani Andrea; Messa, Valdeci; da Cunha Junior, Paulo Luiz; da Silva, Aristeu Vieira; da Eira, Augusto Ferreira; Colauto, Nelson Barros

2009-01-01

93

Antineoplasic activity of Agaricus brasiliensis basidiocarps on different maturation phases.  

PubMed

The fungus Agaricus brasiliensis is a Basidiomycete studied because of its immunomodulation and/or antitumor substances. The objective of this study was to verify the Agaricus brasiliensis antineoplasic activity in vivo on different basidiocarp maturation phases on Sarcoma 180 cells implanted in mice. Sarcoma cells were implanted in mice and after seven days mice were divided in three groups. The first group was treated with saline solution, the second group was treated with closed basidiocarp extract solution and the third group was treated with opened basidiocarp extract solution. After 30 days of being daily orally treated with these three solutions all animals suffered euthanasia, and the splenic index, tumor mass and volume were determined. No significant differences of the tumor growth inhibition in function of the different basidiocarp maturation phases for the Agaricus brasiliensis strain were observed. The in vivo basidiocarp antineoplasic average activity was 89.22%. PMID:24031439

Mourão, Francielly; Linde, Giani Andrea; Messa, Valdeci; da Cunha Júnior, Paulo Luiz; da Silva, Aristeu Vieira; da Eira, Augusto Ferreira; Colauto, Nelson Barros

2009-10-01

94

Melatonin Production in the Sea Star Echinaster brasiliensis (Echinodermata).  

PubMed

The primary hormone of the vertebrate pineal gland, melatonin, has been identified broadly throughout the tree of life, in animals, plants, and fungi, supporting a deep evolutionary origin for this signaling molecule. However, some key groups have not been studied. Echinoderms, deuterostome animals, are one of these groups. Herein we study the presence of melatonin and enzymes of its pathway in the sea star Echinaster brasiliensis. We demonstrate that E. brasiliensis produces endogenous melatonin, in the gonads, under a circadian pattern with a nocturnal peak of production. We also show that the enzymes arylalkylamine N-acetyltransferase (AANAT) and tryptophan hydroxylase (TPH) are present and are probably regulating the melatonin production. PMID:24797096

Peres, Rafael; Amaral, Fernanda Gaspardo; Marques, Antonio Carlos; Neto, José Cipolla

2014-04-01

95

The function of Rad6 gene in Hevea brasiliensis extends beyond DNA repair.  

PubMed

The Rad6 gene of Saccharomyces cerevisiae encodes an ubiquitin-conjugating enzyme (E2) which is required for DNA repair, damage-induced mutagenesis, sporulation, etc. In this study, one Rad6 homolog, designated HbRad6, was cloned in rubber tree (Hevea brasiliensis). The putative protein sequence of HbRad6 contains 152 amino acids, a conserved UBC domain, and a conserved active-site cysteine in the UBC domain, which is required for E2 enzymes catalytic activity. HbRad6 shared high similarity with Rad6 from other species. It shared the highest similarity with rice OsRad6 and Arabidopsis thaliana AtUBC2 with 96.05% identical residues, and 63.16% sequence identity with yeast Rad6 (excluding the acidic tail). Comparing expression among different Hevea tissues demonstrated that HbRad6 was ubiquitously expressed in all tissues, but it revealed a preferential expression in the latex. Furthermore, HbRad6 expression was markedly induced by DNA-damaging agent H2O2, the latex stimulator ethephon (ET), and methyl jasmonate (MeJA), while NaCl and wounding treatments had relatively minor effect upon its expression. Genetic complementation experiment revealed that HbRad6 had minor effects on the complementation of the UV sensitivity of yeast rad6 null mutant, indicating that the Hevea Rad6 protein may partially suppress the UV sensitivity of the yeast rad6 mutant. These results suggested that HbRad6 was a multifunction gene involved in DNA damage repair, hormones and stress responses in rubber tree. PMID:23500716

Qin, Bi

2013-05-01

96

Isolation of scopoletin from leaves of Hevea brasiliensis and the effect of scopoletin on pathogens of H. brasiliensis.  

PubMed

Scopoletin (7-hydroxy-6-methoxy coumarin) which inhibited the conidial germination of Corynespora cassiicola was isolated from the uninfected mature leaves of Hevea brasiliensis. Scopoletin was not detected in uninfected immature rubber leaves. The immature leaves produced scopoletin after being infected with C. cassiicola. The concentration of scopoletin in infected leaves was higher than in uninfected mature leaves. Scopoletin also inhibited the conidial germination of other fungal pathogens of H. brasiliensis. However, no correlation was observed between scopoletin accumulation and clonal resistance. PMID:12014480

Silva, W P K; Deraniyagala, S A; Wijesundera, R L C; Karunanayake, E H; Priyanka, U M S

2002-01-01

97

Mitochondrial DNA polymorphism and phylogenetic relationships in Hevea brasiliensis  

Microsoft Academic Search

Using fourteen random mitochondrial DNA probes, we have examined restriction fragment length polymorphism (RFLP) in wild and cultivatedHevea brasiliensis. A total of 395 accessions, including 345 from various prospectings collected in Brazil, Colombia and Peru and 50 cultivated clones, were analyzed. Two other species (H. benthamiana andH. pauciflora) were also included in the study for comparison. The high level of

Hong Luo; Benoît Van Coppenolle; Marc Seguin; Marc Boutry

1995-01-01

98

Draft genome sequence of the rubber tree Hevea brasiliensis  

PubMed Central

Background Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876. Results Here, we report the draft genome sequence of H. brasiliensis. The assembly spans ~1.1 Gb of the estimated 2.15 Gb haploid genome. Overall, ~78% of the genome was identified as repetitive DNA. Gene prediction shows 68,955 gene models, of which 12.7% are unique to Hevea. Most of the key genes associated with rubber biosynthesis, rubberwood formation, disease resistance, and allergenicity have been identified. Conclusions The knowledge gained from this genome sequence will aid in the future development of high-yielding clones to keep up with the ever increasing need for natural rubber.

2013-01-01

99

Ras Signaling in Yeast  

PubMed Central

Since the study of yeast RAS and adenylate cyclase in the early 1980s, yeasts including budding and fission yeasts contributed significantly to the study of Ras signaling. First, yeast studies provided insights into how Ras activates downstream signaling pathways. Second, yeast studies contributed to the identification and characterization of GAP and GEF proteins, key regulators of Ras. Finally, the study of yeast provided many important insights into the understanding of C-terminal processing and membrane association of Ras proteins.

Tamanoi, Fuyuhiko

2011-01-01

100

High-level intracellular expression of hydroxynitrile lyase from the tropical rubber tree Hevea brasiliensis in microbial hosts.  

PubMed

(S)-Hydroxynitrile lyase (Hnl) from the tropical rubber tree Hevea brasiliensis catalyzes the formation of (S)-cyanohydrins from hydrocyanic acid and aldehydes or ketones. This enzyme accepts aliphatic, aromatic, and heterocyclic carbonyl compounds as substrates and is therefore considered a potent biocatalyst for the industrial production of optically active chemicals. Limitations in enzyme supply from natural resources were overcome by production of the enzyme in the microbial host systems Escherichia coli, Saccharomyces cerevisiae, and Pichia pastoris. Expression of Hnl in the prokaryotic system led to the formation of inclusion bodies whereas in both yeast hosts high levels of soluble protein were obtained. Highest yields were obtained in a high cell density batch fermentation of a P. pastoris transformant that expressed heterologous Hnl to about 50% of the soluble cytosolic protein. At a cell density of 100 g/liter cell dry weight, a volume yield of 22 g/liter of heterologous product was obtained. Attempts to produce the Hnl protein extracellularly with the yeast hosts by applying different leader peptide strategies were not successful. Immunofluorescence microscopy studies indicated that the secretion-directed heterologous Hnl protein accumulated in the plasma membrane forming aggregated clusters of inactive protein. PMID:9325140

Hasslacher, M; Schall, M; Hayn, M; Bona, R; Rumbold, K; Lückl, J; Griengl, H; Kohlwein, S D; Schwab, H

1997-10-01

101

Comparative Genomic Analysis of Human Fungal Pathogens Causing Paracoccidioidomycosis  

PubMed Central

Paracoccidioides is a fungal pathogen and the cause of paracoccidioidomycosis, a health-threatening human systemic mycosis endemic to Latin America. Infection by Paracoccidioides, a dimorphic fungus in the order Onygenales, is coupled with a thermally regulated transition from a soil-dwelling filamentous form to a yeast-like pathogenic form. To better understand the genetic basis of growth and pathogenicity in Paracoccidioides, we sequenced the genomes of two strains of Paracoccidioides brasiliensis (Pb03 and Pb18) and one strain of Paracoccidioides lutzii (Pb01). These genomes range in size from 29.1 Mb to 32.9 Mb and encode 7,610 to 8,130 genes. To enable genetic studies, we mapped 94% of the P. brasiliensis Pb18 assembly onto five chromosomes. We characterized gene family content across Onygenales and related fungi, and within Paracoccidioides we found expansions of the fungal-specific kinase family FunK1. Additionally, the Onygenales have lost many genes involved in carbohydrate metabolism and fewer genes involved in protein metabolism, resulting in a higher ratio of proteases to carbohydrate active enzymes in the Onygenales than their relatives. To determine if gene content correlated with growth on different substrates, we screened the non-pathogenic onygenale Uncinocarpus reesii, which has orthologs for 91% of Paracoccidioides metabolic genes, for growth on 190 carbon sources. U. reesii showed growth on a limited range of carbohydrates, primarily basic plant sugars and cell wall components; this suggests that Onygenales, including dimorphic fungi, can degrade cellulosic plant material in the soil. In addition, U. reesii grew on gelatin and a wide range of dipeptides and amino acids, indicating a preference for proteinaceous growth substrates over carbohydrates, which may enable these fungi to also degrade animal biomass. These capabilities for degrading plant and animal substrates suggest a duality in lifestyle that could enable pathogenic species of Onygenales to transfer from soil to animal hosts.

Desjardins, Christopher A.; Champion, Mia D.; Holder, Jason W.; Muszewska, Anna; Goldberg, Jonathan; Bailao, Alexandre M.; Brigido, Marcelo Macedo; Ferreira, Marcia Eliana da Silva; Garcia, Ana Maria; Grynberg, Marcin; Gujja, Sharvari; Heiman, David I.; Henn, Matthew R.; Kodira, Chinnappa D.; Leon-Narvaez, Henry; Longo, Larissa V. G.; Ma, Li-Jun; Malavazi, Iran; Matsuo, Alisson L.; Morais, Flavia V.; Pereira, Maristela; Rodriguez-Brito, Sabrina; Sakthikumar, Sharadha; Salem-Izacc, Silvia M.; Sykes, Sean M.; Teixeira, Marcus Melo; Vallejo, Milene C.; Walter, Maria Emilia Machado Telles; Yandava, Chandri; Young, Sarah; Zeng, Qiandong; Zucker, Jeremy; Felipe, Maria Sueli; Goldman, Gustavo H.; Haas, Brian J.; McEwen, Juan G.; Nino-Vega, Gustavo; Puccia, Rosana; San-Blas, Gioconda; Soares, Celia Maria de Almeida; Birren, Bruce W.; Cuomo, Christina A.

2011-01-01

102

Taxonomic and Functional Microbial Signatures of the Endemic Marine Sponge Arenosclera brasiliensis  

PubMed Central

The endemic marine sponge Arenosclera brasiliensis (Porifera, Demospongiae, Haplosclerida) is a known source of secondary metabolites such as arenosclerins A-C. In the present study, we established the composition of the A. brasiliensis microbiome and the metabolic pathways associated with this community. We used 454 shotgun pyrosequencing to generate approximately 640,000 high-quality sponge-derived sequences (?150 Mb). Clustering analysis including sponge, seawater and twenty-three other metagenomes derived from marine animal microbiomes shows that A. brasiliensis contains a specific microbiome. Fourteen bacterial phyla (including Proteobacteria, Cyanobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Cloroflexi) were consistently found in the A. brasiliensis metagenomes. The A. brasiliensis microbiome is enriched for Betaproteobacteria (e.g., Burkholderia) and Gammaproteobacteria (e.g., Pseudomonas and Alteromonas) compared with the surrounding planktonic microbial communities. Functional analysis based on Rapid Annotation using Subsystem Technology (RAST) indicated that the A. brasiliensis microbiome is enriched for sequences associated with membrane transport and one-carbon metabolism. In addition, there was an overrepresentation of sequences associated with aerobic and anaerobic metabolism as well as the synthesis and degradation of secondary metabolites. This study represents the first analysis of sponge-associated microbial communities via shotgun pyrosequencing, a strategy commonly applied in similar analyses in other marine invertebrate hosts, such as corals and algae. We demonstrate that A. brasiliensis has a unique microbiome that is distinct from that of the surrounding planktonic microbes and from other marine organisms, indicating a species-specific microbiome.

Trindade-Silva, Amaro E.; Rua, Cintia; Silva, Genivaldo G. Z.; Dutilh, Bas E.; Moreira, Ana Paula B.; Edwards, Robert A.; Hajdu, Eduardo; Lobo-Hajdu, Gisele; Vasconcelos, Ana Tereza; Berlinck, Roberto G. S.; Thompson, Fabiano L.

2012-01-01

103

Nippostrongylus brasiliensis: radioresistant IgE antibody-forming cells in infected rats  

SciTech Connect

In Nippostrongylus brasiliensis-infected rats, anti-N. brasiliensis IgE antibody production was observed at 20 weeks postinfection, long after the worms, as a source of antigen, had been expelled. The persistent IgE production was not abrogated after whole body irradiation (800 R) administered at 12 or 20 weeks, suggesting the participation of radioresistant IgE-forming cells. Help of T cells and recruitment of B memory cells in the irradiated rats seems to be ruled out by the findings that the irradiation completely inhibited the initiation of anti-N. brasiliensis IgE production in rats shortly after the infection with N. brasiliensis or after primary and secondary immunization with N. brasiliensis-antigen. Moreover, clearance of anti-N. brasiliensis IgE antibody from circulation did not seem to be crucially affected by the irradiation. The radioresistant cells forming anti-N. brasiliensis IgE were most productive in mesenteric lymph nodes as compared to other lymph nodes. The recognition of antigens fractionated by chromatography on Sephadex G-200 was the same for IgE-forming cells from rats 12 weeks after infection as for those from 3 weeks after infection. Based on these results, one of the mechanisms of persistent elevation of IgE antibody in the host infected with helminth parasites might be explained by the participation of radioresistant IgE-forming cells.

Watanabe, N.; Kobayashi, A.

1989-02-01

104

High yield production of a mutant Nippostrongylus brasiliensis acetylcholinesterase in Pichia pastoris and its purification.  

PubMed

The mutant M301A of the acetylcholinesterase B from Nippostrongylus brasiliensis (NbAChE) was produced in a high-cell-density fermentation of a recombinant methylotrophic yeast Pichia pastoris. Dissolved oxygen (DO) spikes were used as an indicator for feeding the carbon source. Wet cell weight (WCW) reached after 8 days a maximum value of 316 g/L and the OD600 at this time was 280. The acetylcholinesterase activity increased up to 6,600 U/mL corresponding to an expression rate of 2 g of NbAChE per liter supernatant. The specific activity of the mutant NbAChE was determined after purification as 3,300 U/mg. Active site titration with chlorpyrifos, a strong AChE inhibitor, yielded in a specific activity of 3,400 U/mg. The enzyme was secreted by Pichia pastoris. Therefore, it could be concentrated from culture broth by cross-flow-filtration (50 kDa cut-off membrane). It was further purified in one-step anion-exchange chromatography, using a XK 50/20 column filled with 125 mL Q Sepharose HP. Mutant NbAChE was purified 1.9-fold up to a purity of 97% and a yield of 87%. The isolated enzyme was nearly homogenous, as seen on the silver stained SDS-PAGE as well as by a single peak after gel filtration. This extraordinary high expression rate and the ease of purification is an important prerequisite for their practical application, for example in biosensors for the detection of neurotoxic insecticides. PMID:16302258

Richter, Sven; Nieveler, Jens; Schulze, Holger; Bachmann, Till T; Schmid, Rolf D

2006-04-01

105

Antiherpetic activity of a sulfated polysaccharide from Agaricus brasiliensis mycelia.  

PubMed

Sulfated polysaccharides are good candidates for drug discovery in the treatment of herpetic infections. Agaricus brasiliensis (syn A. subrufescens, A. blazei) is a Basidiomycete fungus native to the Atlantic forest region of Southeastern Brazil. Herein we report the chemical modification of a polysaccharide extracted from A. brasiliensis mycelia to obtain its sulfated derivative (MI-S), which presented a promising inhibitory activity against HSV-1 [KOS and 29R (acyclovir-resistant) strains] and HSV-2 strain 333, with selectivity indices (SI = CC50/IC50) higher than 439, 208, and 562, respectively. The mechanisms underlying this inhibitory activity were scrutinized by plaque assay with different methodological strategies. MI-S had no virucidal effects, but inhibited HSV-1 and HSV-2 attachment, penetration, and cell-to-cell spread, as well as reducing the expression of HSV-1 ICP27, UL42, gB, and gD proteins. MI-S also presented synergistic antiviral effect with acyclovir. These results suggest that MI-S presents multiple modes of anti-HSV action. PMID:21787804

Cardozo, Francielle Tramontini Gomes de Sousa; Camelini, Carla Maísa; Mascarello, Alessandra; Rossi, Márcio José; Nunes, Ricardo José; Barardi, Célia Regina Monte; de Mendonça, Margarida Matos; Simões, Cláudia Maria Oliveira

2011-10-01

106

Yeast Infection (Candidiasis)  

MedlinePLUS

... for adults A A A This is a candida (yeast) infection of the skin folds of the ... infection with the common yeast (or fungus) organism, Candida albicans, which is commonly found in the environment. ...

107

Phenoptosis in yeasts.  

PubMed

The current view on phenoptosis and apoptosis as genetic programs aimed at eliminating potentially dangerous organisms and cells, respectively, is given. Special emphasis is placed on apoptosis (phenoptosis) in yeasts: intracellular defects and a plethora of external stimuli inducing apoptosis in yeasts; distinctive morphological and biochemical hallmarks accompanying apoptosis in yeasts; pro- and antiapoptotic factors involved in yeast apoptosis signaling; consecutive stages of apoptosis from external stimulus to the cell death; a prominent role of mitochondria and other organelles in yeast apoptosis; possible pathways for release of apoptotic factors from the intermembrane mitochondrial space into the cytosol are described. Using some concrete examples, the obvious physiological importance and expediency of altruistic death of yeast cells is shown. Poorly known aspects of yeast apoptosis and prospects for yeast apoptosis study are defined. PMID:22817540

Sukhanova, E I; Rogov, A G; Severin, F F; Zvyagilskaya, R A

2012-07-01

108

Yeast Based Sensors  

NASA Astrophysics Data System (ADS)

Since the first microbial cell sensor was studied by Karube et al. in 1977, many types of yeast based sensors have been developed as analytical tools. Yeasts are known as facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic conditions. The yeast based sensor consisted of a DO electrode and an immobilized omnivorous yeast. In yeast based sensor development, many kinds of yeast have been employed by applying their characteristics to adapt to the analyte. For example, Trichosporon cutaneum was used to estimate organic pollution in industrial wastewater. Yeast based sensors are suitable for online control of biochemical processes and for environmental monitoring. In this review, principles and applications of yeast based sensors are summarized.

Shimomura-Shimizu, Mifumi; Karube, Isao

109

Lager brewing yeast  

Microsoft Academic Search

Lager brewing yeast is a group of closely related strains of Saccharomyces pastorianus\\/S. carlsbergensis used for lager beer production all over the world, making it one of the most important industrial yeasts. The pure cultivation\\u000a of yeast was established in the early 1880’s with immediate practical success for lager brewing yeast. However, almost a century\\u000a would elapse before its genetics

Yukiko Kodama; Morten C. Kielland-Brandt; Jørgen Hansen

110

Black yeast-like fungi associated with Lethargic Crab Disease (LCD) in the mangrove-land crab, Ucides cordatus (Ocypodidae).  

PubMed

Lethargic Crab Disease (LCD) caused extensive epizootic mortality of the mangrove land crab Ucides cordatus (Brachyura: Ocypodidae) along the Brazilian coast, mainly in the Northeastern region. The disease was named after the symptoms of slow movement of infected crabs. Causative agents were suspected to be two black yeast-like fungi of the family Herpotrichiellaceae (ascomycete order Chaetothyriales), judged by infected tissue biopsies from moribund U. cordatus. The aim of the present study is to prove that two species are involved in the disease: the recently described black yeast Exophiala cancerae, but also a less virulent, hitherto undescribed fonsecaea-like species, introduced here as the novel species Fonsecaea brasiliensis. Strains were identified by ITS rDNA sequencing, and species borderlines were established by multilocus sequencing and AFLP analysis. Fonsecaea brasiliensis proved to be closely related to the pathogenic species Cladophialophora devriesii which originally was isolated from a systemic infection in a human patient. The virulence of F. brasiliensis is lower than that of E. cancerae, as established by artificial inoculation of mangrove crabs. PMID:22440399

Vicente, Vania A; Orélis-Ribeiro, R; Najafzadeh, M J; Sun, Jiufeng; Guerra, Raquel Schier; Miesch, Stephanie; Ostrensky, Antonio; Meis, Jacques F; Klaassen, Corné H; de Hoog, G S; Boeger, Walter A

2012-07-01

111

Xylose fermentation by yeasts  

Microsoft Academic Search

Utilization and fermentation of xylose by the yeasts Pachysolen tannophilus I fGB 0101 and Pichia stipitis 5773 to 5776 under aerobic and anaerobic conditions are investigated. Pa. tannophilus requires biotin and thiamine for growth, whereas Pi. stipitis does not, and growth of both yeasts is stimulated by yeast extract. Pi. stipitis converts xylose (30 g\\/l) to ethanol under anaerobic conditions

H. Dellweg; M. Rizzi; H. Methner; D. Debus

1984-01-01

112

Desarrollo embrionario-larval y tiempo de metamorfosis del pez tropical Xenomelaniris brasiliensis (Pisces: Atherinidae)  

Microsoft Academic Search

Development of the tropical fish Xenomelaniris brasiliensis (Pisces: Atherinidae) from embryo to larva and time to metamorphosis. Embryonic-larval development, and metamorphosis larval time, were stud- ied in the tropical fish Xenomelaniris brasiliensis. Twenty nine sexually mature specimens were used, 16 females (10.86 ± 1.01 cm and 7.63 ± 2.62 g) and 13 males (10.43 ± 0.57 cm and 6.54 ±

Veronica del Río; Jesús Rosas; Aidé Velásquez; Tomas Cabrera

2005-01-01

113

Interleukin4-Promoted T Helper 2 Responses Enhance Nippostrongylus brasiliensis-Induced Pulmonary Pathology  

Microsoft Academic Search

The role of CD4 T-cell interleukin-4 (IL-4) receptor alpha (IL-4R) expression in T helper 2 (TH2) immune responses has not been defined. To examine this role, we infected CD4 T-cell IL-4R knockout (KO) mice with the parasitic nematode Nippostrongylus brasiliensis, which induces strong host TH2 responses. Although N. brasiliensis expulsion was not affected in CD4 T-cell IL-4R KO mice, the

Helen Mearns; William G. C. Horsnell; J. Claire Hoving; Benjamin Dewals; Antony J. Cutler; Frank Kirstein; Elmarie Myburgh; Berenice Arendse; Frank Brombacher

2008-01-01

114

Isolation and characterization of microsatellite markers in the Serra Spanish mackerel, Scomberomorus brasiliensis.  

PubMed

Thirteen nuclear-encoded microsatellites from a genomic DNA library of Serra Spanish mackerel, Scomberomorus brasiliensis, were isolated and characterized. The microsatellites include 10 perfect repeats (eight tetranucleotide and two dinucleotide) and three imperfect repeats (two tetranucleotide and one dinucleotide). An additional five microsatellites, isolated originally from two congeneric species (S. cavalla and S. niphonius), were characterized in S. brasiliensis. Serra Spanish mackerel support artisanal fisheries along the Caribbean and Atlantic coasts of Central and South America, from Belize to Brazil. PMID:21564761

Renshaw, Mark A; Douglas, Kory C; Rexroad Iii, Caird E; Jobity, Ann Marie C; Gold, John R

2009-05-01

115

Phylogenetic Analysis Reveals a High Prevalence of Sporothrix brasiliensis in Feline Sporotrichosis Outbreaks  

PubMed Central

Sporothrix schenckii, previously assumed to be the sole agent of human and animal sporotrichosis, is in fact a species complex. Recently recognized taxa include S. brasiliensis, S. globosa, S. mexicana, and S. luriei, in addition to S. schenckii sensu stricto. Over the last decades, large epidemics of sporotrichosis occurred in Brazil due to zoonotic transmission, and cats were pointed out as key susceptible hosts. In order to understand the eco-epidemiology of feline sporotrichosis and its role in human sporotrichosis a survey was conducted among symptomatic cats. Prevalence and phylogenetic relationships among feline Sporothrix species were investigated by reconstructing their phylogenetic origin using the calmodulin (CAL) and the translation elongation factor-1 alpha (EF1?) loci in strains originated from Rio de Janeiro (RJ, n?=?15), Rio Grande do Sul (RS, n?=?10), Paraná (PR, n?=?4), São Paulo (SP, n?=?3) and Minas Gerais (MG, n?=?1). Our results showed that S. brasiliensis is highly prevalent among cats (96.9%) with sporotrichosis, while S. schenckii was identified only once. The genotype of Sporothrix from cats was found identical to S. brasiliensis from human sources confirming that the disease is transmitted by cats. Sporothrix brasiliensis presented low genetic diversity compared to its sister taxon S. schenckii. No evidence of recombination in S. brasiliensis was found by split decomposition or PHI-test analysis, suggesting that S. brasiliensis is a clonal species. Strains recovered in states SP, MG and PR share the genotype of the RJ outbreak, different from the RS clone. The occurrence of separate genotypes among strains indicated that the Brazilian S. brasiliensis epidemic has at least two distinct sources. We suggest that cats represent a major host and the main source of cat and human S. brasiliensis infections in Brazil.

Rodrigues, Anderson Messias; de Melo Teixeira, Marcus; de Hoog, G. Sybren; Schubach, Tania Maria Pacheco; Pereira, Sandro Antonio; Fernandes, Geisa Ferreira; Bezerra, Leila Maria Lopes; Felipe, Maria Sueli; de Camargo, Zoilo Pires

2013-01-01

116

Culturable bacterial diversity associated with cysts of Eurhizococcus brasiliensis (Hempel) (Hemiptera: Margarodidae)  

Microsoft Academic Search

The ground-pearl Eurhizococcus brasiliensis is an important insect pest of grapes. Nowadays, its biology is still barely known and studies related to its secondary symbionts\\u000a are virtually non-existent. Our main goal was to evaluate the bacterial diversity associated with cysts of E. brasiliensis using a culture-dependent approach. Six different isolation media were used and shown to be suitable for culturing

Tiago D. ZucchiLuis; Luis G. Almeida; Fernando L. Cônsoli

2011-01-01

117

Eremophilanolides and other constituents from the Argentine liverwort Frullania brasiliensis.  

PubMed

Two eremophilanolides, 5-epidilatanolides A and B, as well as a new natural bibenzyl were isolated from an Argentine collection of the liverwort Frullania brasiliensis, along with the known eudesmane-type sesquiterpene lactones nepalensolide A, nepalensolide B, (+)-frullanolide, and (+)-dihydrofrullanolide, the hopanoid zeorin, the four sterols stigmasta-4,22-dien-3,6-dione, stigmasta-4,22-dien-3-one, stigmasterol, and sitosterol, and a trace amount of atraric acid. The structure and stereochemistry of the eremophilanolides and the bibenzyl were established by a combination of extensive NMR spectroscopy experiments and X-ray crystallographic analysis. Absolute configurations of the new compounds were derived on the basis of CD spectra. PMID:11809457

Bardón, Alicia; Mitre, Graciela Bovi; Kamiya, Norma; Toyota, Masao; Asakawa, Yoshinori

2002-01-01

118

[Primary cutaneous Nocardia brasiliensis cellulitis in immunocompetent child].  

PubMed

Primary cutaneous nocardiosis is an infrequent infection among children, generally affecting immunocompromised hosts. It is caused by Gram positive bacteria, partially alcohol and acid resistant which are saprophytes of the soil, water and organic matter. In most cases the causal agent enters through inhalation, and hematogenous dissemination may occur mainly among the immune compromised patients. Direct cutaneous inoculation is less frequent, especially among children. We report an 8-year old female who lives in an urban house with a small garden, who presented with an ulcer on her right shin accompanied by surrounding cellulitis, pain, swelling and fever. The patient's medical history was unremarkable, with no exposure to animals or travelling, except for rafting on the Jordan River the previous week. Culture from the ulcer grew Nocardia brasiliensis, and she recovered after 8 weeks of therapy with trimethoprim-sulphamethoxazole. PMID:23350294

Shachor-Meyouhas, Yael; Ravid, Sarit; Suhair, Hanna; Kassis, Imad

2012-08-01

119

Drimanes from Drimys brasiliensis with leishmanicidal and antimalarial activity  

PubMed Central

This paper evaluates CHCl3 and CH3OH extracts of the stem bark, branches and leaves of Drimys brasiliensis and drimane sesquiterpenes isolated from the stem bark against strains of Leishmania amazonensis and Leishmania braziliensis promastigotes and Plasmodium falciparum trophozoites. All of the extracts and compounds were tested in cell lines in comparison with reference standards and cell viability was determined by the XTT method. The CHCl3 and CH3OH extracts from the stem bark and branches yielded promising results against two strains of Leishmania, with 50% inhibitory concentrations (IC50 ) values ranging from 39-100 µg/mL. The CHCl3 extract of the stem bark returned IC50 values of 39 and 40.6 µg/mL for L. amazonensis and L. braziliensis, respectively. The drimanes were relatively effective: 1-?-(p-coumaroyloxy)-polygodial produced IC50 values of 5.55 and 2.52 µM for L. amazonensis and L. braziliensis, respectively, compared with 1-?-(p-methoxycinnamoyl)-polygodial, which produced respective IC50 values of 15.85 and 17.80 µM. The CHCl3 extract demonstrated activity (IC50 of 3.0 µg/mL) against P. falciparum. The IC50 values of 1-?-(p-cumaroyloxyl)-polygodial and 1-?-(p-methoxycinnamoyl)-polygodial were 1.01 and 4.87 µM, respectively, for the trophozoite strain. Therefore, the results suggest that D. brasiliensis is a promising plant from which to obtain new and effective antiparasitic agents.

Claudino, Vanessa Duarte; da Silva, Kesia Caroline; Cechinel, Valdir; Yunes, Rosendo Augusto; Monache, Franco Delle; Gimenez, Alberto; Salamanca, Efrain; Gutierrez-Yapu, David; Malheiros, Angela

2013-01-01

120

Cloning and characterization of pectate lyase from Hevea brasiliensis.  

PubMed

Latex from the commercial Hevea brasiliensis contains 30-50% (w/w) of natural rubber (cis-1,4-polyisoprene), the raw material for the many products of the rubber industry. We have constructed a cDNA library from the latex of H. brasiliensis to investigate the expressed genes and molecular events in the latex. We have isolated two cDNAs from this library, Hb-PEL-1 and Hb-PEL-2 that could encode for pectate lyase enzymes (EC4.2.2.2). From their sequence analysis Hb-PEL-1 and Hb-PEL-2 encode for proteins of 393 and 323 amino acids, respectively. Comparison of these deduced amino acid sequences with other pectate lyase enzymes showed they contained the conserved NADPH, Ca(2+) and substrate binding sites and had a 74% identity to Arabidopsis thaliana pectate lyase. Only the Hb-PEL-1 recombinant protein expressed from Escherichia coli had enzymic activity which was Ca(2+) dependent. Interestingly, Hb-PEL-1 contained an extra internal peptide between amino acid residue 38-108 when compared to Hb-PEL-2 and this peptide was also present in other pectate lyase enzymes. The transcript of pectate lyase (Hb-PEL) in the latex of rubber tree at various times after the first tapping was quantified by real-time PCR using 18s genes as internal standard. Most transcripts were detected on the first day after tapping and then decreased with time. This indicates that the pectate lyase may be involved in either the release of latex by breaking down the laticifer wall or in the development of laticifers. PMID:19144526

Chotigeat, Wilaiwan; Duangchu, Sarapee; Wititsuwannakun, Rapepun; Phongdara, Amornrat

2009-04-01

121

Heterologous Protein Secretion from Yeast  

Microsoft Academic Search

Secretion of calf prochymosin from yeast yields fully activable zymogen while production in the yeast cytoplasm yields insoluble, unactivable enzyme with aberrant disulfide bonding. Factors that increase the efficiency of secretion of prochymosin from yeast are use of a yeast secretion signal sequence, integration of the transcriptional unit into the yeast genome, and specific mutations in a number of host

Robert A. Smith; Margaret J. Duncan; Donald T. Moir

1985-01-01

122

Population Growth in Yeasts  

NSDL National Science Digital Library

This lesson is the second of two that explore cellular respiration and population growth in yeasts. In the first lesson, students set up a simple way to indirectly observe and quantify the amount of respiration occurring in yeast-molasses cultures. Based on questions that arose during the first lesson and its associated activity, in this lesson students work in small groups to design experiments that will determine how environmental factors affect yeast population growth.

Engineering K-Ph.d. Program

123

The crystal structure of Canavalia brasiliensis lectin suggests a correlation between its quaternary conformation and its distinct biological properties from Concanavalin A  

Microsoft Academic Search

Canavalia brasiliensis lectin was isolated from the seeds of a Brazilian autochthonous Leguminosae plant. Despite extensive amino acid sequence similarity with Concanavalin A, C. brasiliensis lectin exerts in vitro and in vivo cellular effects that are markedly different from those displayed by Concanavalin A. We have solved the crystal structure of the C. brasiliensis lectin at 3.0 Å resolution. The

Julia Sanz-Aparicio; Juan Hermoso; Thalles B Grangeiro; Juan J Calvete; Benildo S Cavada

1997-01-01

124

Draft Genome Sequence of Pseudozyma brasiliensis sp. nov. Strain GHG001, a High Producer of Endo-1,4-Xylanase Isolated from an Insect Pest of Sugarcane.  

PubMed

Here, we present the nuclear and mitochondrial genome sequences of Pseudozyma brasiliensis sp. nov. strain GHG001. P. brasiliensis sp. nov. is the closest relative of Pseudozyma vetiver. P. brasiliensis sp. nov. is capable of growing on xylose or xylan as a sole carbon source and has great biotechnological potential. PMID:24356824

Oliveira, Juliana Velasco de Castro; Dos Santos, Renato Augusto Corrêa; Borges, Thuanny A; Riaño-Pachón, Diego Mauricio; Goldman, Gustavo Henrique

2013-01-01

125

Draft Genome Sequence of Pseudozyma brasiliensis sp. nov. Strain GHG001, a High Producer of Endo-1,4-Xylanase Isolated from an Insect Pest of Sugarcane  

PubMed Central

Here, we present the nuclear and mitochondrial genome sequences of Pseudozyma brasiliensis sp. nov. strain GHG001. P. brasiliensis sp. nov. is the closest relative of Pseudozyma vetiver. P. brasiliensis sp. nov. is capable of growing on xylose or xylan as a sole carbon source and has great biotechnological potential.

Oliveira, Juliana Velasco de Castro; dos Santos, Renato Augusto Correa; Borges, Thuanny A.

2013-01-01

126

Keratitis caused by the recently described new species Aspergillus brasiliensis: two case reports  

PubMed Central

Introduction Human infections caused by Aspergillus brasiliensis have not yet been reported. We describe the first two known cases of fungal keratitis caused by Aspergillus brasiliensis. Case presentations A 49-year-old Indian Tamil woman agricultural worker came with pain and defective vision in the right eye for one month. Meanwhile, a 35-year-old Indian Tamil woman presented with a history of a corneal ulcer involving the left eye for 15 days. The fungal strains isolated from these two cases were originally suspected to belong to Aspergillus section Nigri based on macro- and micromorphological characteristics. Molecular identification revealed that both isolates represent A. brasiliensis. Conclusion The two A. brasiliensis strains examined in this study were part of six keratitis isolates from Aspergillus section Nigri, suggesting that this recently described species may be responsible for a significant proportion of corneal infections caused by black Aspergilli. The presented cases also indicate that significant differences may occur between the severities of keratitis caused by individual isolates of A. brasiliensis.

2010-01-01

127

In vivo protective effect of the lectin from Canavalia brasiliensis on BALB\\/c mice infected by Leishmania amazonensis  

Microsoft Academic Search

In vivo administration of Canavalia brasiliensis lectin (at the time of infection, or maintained throughout the infection) reduced the lesions of highly susceptible BALB\\/c mice infected by Leishmania amazonensis. At the doses used C. brasiliensis lectin (ConBr) does not interfere with penetration or fate of Leishmania in the macrophages in vitro. Since Interferon-? (IFN-?) is the major macrophage activating factor,

M. Barral-Netto; R. L. Von Sohsten; M. Teixeira; W. L. Conrado dos Santos; M. L. Pompeu; R. A. Moreira; J. T. A. Oliveira; B. S. Cavada; E. Falcoff; A. Barral

1996-01-01

128

Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex.  

PubMed

The cytosolic mevalonate (MVA) pathway in Hevea brasiliensis latex is the conventionally accepted pathway which provides isopentenyl diphosphate (IPP) for cis-polyisoprene (rubber) biosynthesis. However, the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway may be an alternative source of IPP since its more recent discovery in plants. Quantitative RT-PCR (qRT-PCR) expression profiles of genes from both pathways in latex showed that subcellular compartmentalization of IPP for cis-polyisoprene synthesis is related to the degree of plastidic carotenoid synthesis. From this, the occurrence of two schemes of IPP partitioning and utilization within one species is proposed whereby the supply of IPP for cis-polyisoprene from the MEP pathway is related to carotenoid production in latex. Subsequently, a set of latex unique gene transcripts was sequenced and assembled and they were then mapped to IPP-requiring pathways. Up to eight such pathways, including cis-polyisoprene biosynthesis, were identified. Our findings on pre- and post-IPP metabolic routes form an important aspect of a pathway knowledge-driven approach to enhancing cis-polyisoprene biosynthesis in transgenic rubber trees. PMID:22162870

Chow, Keng-See; Mat-Isa, Mohd-Noor; Bahari, Azlina; Ghazali, Ahmad-Kamal; Alias, Halimah; Mohd-Zainuddin, Zainorlina; Hoh, Chee-Choong; Wan, Kiew-Lian

2012-03-01

129

Differential gene expression in different types of Hevea brasiliensis roots.  

PubMed

Three types of roots (taproots, first order laterals and second order laterals) were functionally characterized on 7-month-old in vitro plantlets regenerated by somatic embryogenesis in Hevea brasiliensis. A histological analysis revealed different levels of differentiation depending on root diameter. A primary structure was found in first and second order lateral roots, while taproots displayed a secondary structure. The expression of 48 genes linked to some of the regulatory pathways acting in roots was compared in leaves, stems and the different types of roots by real-time RT-PCR. Thirteen genes were differentially expressed in the different organs studied in plants grown under control conditions. Nine additional other genes were differentially regulated between organs under water deficit conditions. In addition, 10 genes were significantly regulated in response to water deficit, including 8 regulated mainly in lateral roots types. Our results suggest that the regulation of gene expression in lateral roots is different than that in taproots, which have a main role in nutrient uptake and transport, respectively. PMID:22195588

Putranto, Riza-Arief; Sanier, Christine; Leclercq, Julie; Duan, Cuifang; Rio, Maryannick; Jourdan, Christophe; Thaler, Philippe; Sabau, Xavier; Argout, Xavier; Montoro, Pascal

2012-02-01

130

Activation of the Na+, K(+)-ATPase in Narcine brasiliensis.  

PubMed Central

The in vivo activation and turnover rates of the sodium pump (Na+, K(+)-ATPase) were investigated in the electrocytes of the electric organ of the elasmobranch Narcine brasiliensis. The Narcine electric organ appears to be an excellent model for the study of sodium pump activation in an excitable tissue. The sodium transmembrane gradient and high-energy phosphagens were concurrently measured by 23Na and 31P NMR spectroscopy. The resting electric organ, which depends primarily on anaerobic metabolism, displays a high concentration of phosphocreatine (PCr). It has an intracellular sodium concentration ([Na+]i) of 20 +/- 10 milliequivalents/liter as estimated by NMR. Electrical stimulation of the nerves innervating the electric organ results in an increase in [Na+]i in the electrolyte and rapid depletion of PCr. Ouabain causes an 85% decrease in utilization of high-energy phosphagens, indicating that rapid PCr turnover in this tissue is mainly due to Na+, K(+)-ATPase activity. From these data we can determine that the rate of sodium pump turnover increases by greater than 3 orders of magnitude within several hundred milliseconds. In excised unstimulated electric organ slices, changes in [Na+]i equivalent to those occurring with stimulation, but induced by hyperosmolar conditions, do not result in increased PCr hydrolysis. We conclude that cholinergic stimulation of the electric organ causes a rapid and extremely large increase in sodium pump turnover, which is regulated predominantly by factors other than [Na+]i. Images

Blum, H; Nioka, S; Johnson, R G

1990-01-01

131

Isolation and purification of two immunodominant antigens from Nocardia brasiliensis.  

PubMed Central

Two immunogenic proteins from a crude extract of Nocardia brasiliensis were purified to homogeneity. A 61-kDa protein (P61) was isolated from a 50% ammonium sulfate precipitate in two steps. Initially, P61 was obtained by electroelution in a 10% nondenatured preparative polyacrylamide gel electrophoresis (PAGE). In a second step, the eluate from the nondenatured gel was run in a 12% sodium dodecyl sulfate (SDS) preparative polyacrylamide gel. After elution, a single band was demonstrated by SDS-PAGE and Western blot (immunoblot). Also, a 24-kDa immunogenic protein (P24) was isolated by gel filtration in a Sephadex G-100 column and then by electroelution in a 12% nondenatured polyacrylamide gel. In a previous paper, we showed by Western blot assays that these proteins are recognized by the sera of mycetoma patients and not by sera from mycobacterial-infected or healthy individuals. We consider these proteins to be good candidates for the study of the host-parasite relationship in nocardial infections. The possible clinical application of these purified antigens in a serological diagnosis is discussed. Images

Vera-Cabrera, L; Salinas-Carmona, M C; Welsh, O; Rodriguez, M A

1992-01-01

132

Reaginic antibodies and immunity to Nippostrongylus brasiliensis in the rat  

PubMed Central

1. Passive transfer of immunity to Nippostrongylus brasiliensis with pooled antiserum from immune rats was neutralized in vivo by intravenous injection of small amounts of a saline extract of adult worms. This inhibition of protection was associated with systemic anaphylaxis and appeared to result from the neutralization of protective antibodies. 2. Serum from infected rats was fractionated by G-200 Sephadex gel-filtration. Reaginic antibodies were shown to be intermediate in molecular size between 7S and 19S globulins in sera from both singly and multiply infected animals. In immunoelectrophoresis they migrated with fast immunoglobulins but could not be related to either IgG or IgA rat immunoglobulins. The same serum fractions gave both homologous passive cutaneous anaphylaxis (PCA) and systemic anaphylaxis. 3. Blocking antibodies were found both in the 7S and 19S fractions after separation on G-200 Sephadex. These antibodies were found in sera from rats immunized with worm extracts as well as in sera from singly and multiply infected animals. 4. The saline extract of adult worms was fractionated on G-200 Sephadex. The isolated antigenic material (allergen) for both homologous PCA and systemic anaphylaxis seemed to be a protein with a molecular weight of approximately 12,000–17,000. ImagesFIG. 4FIG. 6FIG. 8

Jones, Valerie E.; Ogilvie, Bridget M.

1967-01-01

133

Moonlighting Proteins in Yeasts  

PubMed Central

Proteins able to participate in unrelated biological processes have been grouped under the generic name of moonlighting proteins. Work with different yeast species has uncovered a great number of moonlighting proteins and shown their importance for adequate functioning of the yeast cell. Moonlighting activities in yeasts include such diverse functions as control of gene expression, organelle assembly, and modification of the activity of metabolic pathways. In this review, we consider several well-studied moonlighting proteins in different yeast species, paying attention to the experimental approaches used to identify them and the evidence that supports their participation in the unexpected function. Usually, moonlighting activities have been uncovered unexpectedly, and up to now, no satisfactory way to predict moonlighting activities has been found. Among the well-characterized moonlighting proteins in yeasts, enzymes from the glycolytic pathway appear to be prominent. For some cases, it is shown that despite close phylogenetic relationships, moonlighting activities are not necessarily conserved among yeast species. Organisms may utilize moonlighting to add a new layer of regulation to conventional regulatory networks. The existence of this type of proteins in yeasts should be taken into account when designing mutant screens or in attempts to model or modify yeast metabolism.

Gancedo, Carlos; Flores, Carmen-Lisset

2008-01-01

134

Diversity and antimicrobial potential of culturable heterotrophic bacteria associated with the endemic marine sponge Arenosclera brasiliensis  

PubMed Central

Marine sponges are the oldest Metazoa, very often presenting a complex microbial consortium. Such is the case of the marine sponge Arenosclera brasiliensis, endemic to Rio de Janeiro State, Brazil. In this investigation we characterized the diversity of some of the culturable heterotrophic bacteria living in association with A. brasiliensis and determined their antimicrobial activity. The genera Endozoicomonas (N = 32), Bacillus (N = 26), Shewanella (N = 17), Pseudovibrio (N = 12), and Ruegeria (N = 8) were dominant among the recovered isolates, corresponding to 97% of all isolates. Approximately one third of the isolates living in association with A. brasiliensis produced antibiotics that inhibited the growth of Bacillus subtilis, suggesting that bacteria associated with this sponge play a role in its health.

Rua, Cintia P.J.; Trindade-Silva, Amaro E.; Appolinario, Luciana R.; Venas, Taina M.; Garcia, Gizele D.; Carvalho, Lucas S.; Lima, Alinne; Kruger, Ricardo; Pereira, Renato C.; Berlinck, Roberto G.S.; Valle, Rogerio A.B.; Thompson, Cristiane C.

2014-01-01

135

Aspergillus brasiliensis sp. nov., a biseriate black Aspergillus species with world-wide distribution.  

PubMed

A novel species, Aspergillus brasiliensis sp. nov., is described within Aspergillus section Nigri. This species can be distinguished from other black aspergilli based on intergenic transcribed region, beta-tubulin and calmodulin gene sequences, by amplified fragment length polymorphism analysis and by extrolite profiles. A. brasiliensis isolates produced naphtho-gamma-pyrones, tensidol A and B and pyrophen in common with Aspergillus niger and Aspergillus tubingensis, but also several unique compounds, justifying their treatment as representing a separate species. None of the isolates were found to produce ochratoxin A, kotanins, funalenone or pyranonigrins. The novel species was most closely related to A. niger, and was isolated from soil from Brazil, Australia, USA and The Netherlands, and from grape berries from Portugal. The type strain of Aspergillus brasiliensis sp. nov. is CBS 101740(T) (=IMI 381727(T)=IBT 21946(T)). PMID:17684283

Varga, János; Kocsubé, Sándor; Tóth, Beáta; Frisvad, Jens C; Perrone, Giancarlo; Susca, Antonia; Meijer, Martin; Samson, Robert A

2007-08-01

136

Purinergic effects of a hydroalcoholic Agaricus brasiliensis (A. blazei) extract on liver functions.  

PubMed

The effects of a hydroalcoholic extract of Agaricus brasiliensis (A. blazei) on functional parameters in the perfused rat liver were examined with emphasis on its content of nucleotides and nucleosides. Several nucleosides and nucleotides were identified in the A. brasiliensis extract, which was active on several liver functions. A significant part of the effects is the result of the purinergic action of nucleosides and nucleotides: pressure increment, glycogenolysis stimulation, transient inhibition of oxygen consumption, and redox state changes. Other phenomena such as the stimulation of gluconeogenesis, ureogenesis, and oxygen consumption are more likely consequences of the metabolic transformation of substrates contained within the extract, especially amino acids. It seems apparent that consumption of A. brasiliensis represents not only the ingestion of metabolic precursors but also the ingestion of substances that, even at low concentrations, can exert important signaling functions in the liver as well as in the organism as a whole. PMID:20507067

de Oliveira, Andrea L; Eler, G Jacklin; Bracht, Adelar; Peralta, Rosane M

2010-06-23

137

Diversity and antimicrobial potential of culturable heterotrophic bacteria associated with the endemic marine sponge Arenosclera brasiliensis.  

PubMed

Marine sponges are the oldest Metazoa, very often presenting a complex microbial consortium. Such is the case of the marine sponge Arenosclera brasiliensis, endemic to Rio de Janeiro State, Brazil. In this investigation we characterized the diversity of some of the culturable heterotrophic bacteria living in association with A. brasiliensis and determined their antimicrobial activity. The genera Endozoicomonas (N = 32), Bacillus (N = 26), Shewanella (N = 17), Pseudovibrio (N = 12), and Ruegeria (N = 8) were dominant among the recovered isolates, corresponding to 97% of all isolates. Approximately one third of the isolates living in association with A. brasiliensis produced antibiotics that inhibited the growth of Bacillus subtilis, suggesting that bacteria associated with this sponge play a role in its health. PMID:25024903

Rua, Cintia P J; Trindade-Silva, Amaro E; Appolinario, Luciana R; Venas, Tainá M; Garcia, Gizele D; Carvalho, Lucas S; Lima, Alinne; Kruger, Ricardo; Pereira, Renato C; Berlinck, Roberto G S; Valle, Rogério A B; Thompson, Cristiane C; Thompson, Fabiano

2014-01-01

138

Antiherpetic activity of an Agaricus brasiliensis polysaccharide, its sulfated derivative and fractions.  

PubMed

Agaricus brasiliensis is an edible mushroom, traditionally used for the treatment of several diseases. In this paper, a polysaccharide (PLS) from A. brasiliensis, its carboxymethylated (CPLS) and sulfated (SPLS) derivatives, as well as, fractions (F1-F3) obtained from the PLS were investigated for their effect in the replication of herpes simplex virus and bovine herpes virus in HEp-2 cell cultures. The PLS, SPLS and F3 inhibited both virus strains similarly, in a dose-dependent curve. F1, F2 and CPLS did not show significant effect even at higher concentrations. All the compounds showed neither virucidal or viral adsorption inhibition activities nor effect when cells were treated prior to infection. Our study demonstrated that the extracts of A. brasiliensis, can be promising for future antiviral drug design and its biotechnological production is economically feasible. PMID:23043759

Yamamoto, Kristie Aimi; Galhardi, Lígia Carla Faccin; Rincão, Vinícius Pires; Soares, Sandra de Aguiar; Vieira, Icaro Gusmão Pinto; Ricardo, Nágila Maria Pontes Silva; Nozawa, Carlos; Linhares, Rosa Elisa Carvalho

2013-01-01

139

Immunomodulating Activity of Agaricus brasiliensis KA21 in Mice and in Human Volunteers  

PubMed Central

We performed studies on murine models and human volunteers to examine the immunoenhancing effects of the naturally outdoor-cultivated fruit body of Agaricus brasiliensis KA21 (i.e. Agaricus blazei). Antitumor, leukocyte-enhancing, hepatopathy-alleviating and endotoxin shock-alleviating effects were found in mice. In the human study, percentage body fat, percentage visceral fat, blood cholesterol level and blood glucose level were decreased, and natural killer cell activity was increased. Taken together, the results strongly suggest that the A. brasiliensis fruit body is useful as a health-promoting food.

Fukuwatari, Yasushi; Okumura, Ko; Takeda, Kazuyoshi; Ishibashi, Ken-ichi; Furukawa, Mai; Ohno, Naohito; Mori, Kazu; Gao, Ming; Motoi, Masuro

2008-01-01

140

Occurrence of Ornithodoros brasiliensis Aragão (Acari: Argasidae) in São Francisco de Paula, RS, Southern Brazil.  

PubMed

There have been no reports of the endemic Ornithodoros brasiliensis (Aragão) in Rio Grande do Sul, southern Brazil, since the 1950s. In January 2007, 21 O. brasiliensis ticks were collected in a rural area named "Cruzinha" in the municipality of São Francisco de Paula, RS, and another population was sampled later that year (October) in Vargem do Cedro, another rural area of São Francisco de Paula, following reports of human parasitism by ticks. The reappearance of this tick is a reason for concern in terms of public health. PMID:21437496

Martins, J R; Doyle, R L; Barros-Battesti, D M; Onofrio, V C; Guglielmone, A A

2011-01-01

141

Molecular characterization of a novel 14-3-3 protein gene (Hb14-3-3c) from Hevea brasiliensis.  

PubMed

The cDNA encoding a 14-3-3 protein, designated as Hb14-3-3c, was isolated from Hevea brasiliensis. Hb14-3-3c was 1,269 bp long containing a 795 bp open reading frame encoding a putative protein of 264 amino acids, flanked by a 146 bp 5'UTR and a 328 bp 3' UTR. The predicted molecular mass of Hb14-3-3c is 29.67 kDa, with an isoelectric point of 4.52 and the deduced protein showed high similarity to the 14-3-3 protein from other plant species. Expression analysis revealed more significant accumulation of Hb14-3-3c transcripts in latex than in leaves, buds and flowers. The transcription of Hb14-3-3c in latex was induced by jasmonate and ethephon. Overproduction of recombinant Hb14-3-3c protein gave the Escherichia coli cells more tolerance on Co(2+), Cu(2+) and Zn(2+). Through yeast two-hybrid screening, 11 interaction partners of the Hb14-3-3c, which are involved in rubber biosynthesis, stress-related responses, defence etc., were identified in rubber tree latex. Taking these data together, it is proposed that the Hb14-3-3c may participate in regulation of rubber biosynthesis. Thus, the results of this study provide novel insights into the 14-3-3 signaling related to rubber biosynthesis, stress-related responses in rubber tree. PMID:21947841

Yang, Zi-Ping; Li, Hui-Liang; Guo, Dong; Tian, Wei-Min; Peng, Shi-Qing

2012-04-01

142

RNAi in budding yeast  

PubMed Central

RNAi, a gene-silencing pathway triggered by double-stranded RNA, is conserved in diverse eukaryotic species but has been lost in the model budding yeast, Saccharomyces cerevisiae. Here, we show that RNAi is present in other budding-yeast species, including Saccharomyces castellii and Candida albicans. These species use noncanonical Dicer proteins to generate siRNAs, which mostly correspond to transposable elements and Y’ subtelomeric repeats. In S. castellii, RNAi mutants are viable but have excess Y’ mRNA levels. In S. cerevisiae, introducing Dicer and Argonaute of S. castellii restores RNAi, and the reconstituted pathway silences endogenous retrotransposons. These results identify a novel class of Dicer proteins, bring the tool of RNAi to the study of budding yeasts, and bring the tools of budding yeast to the study of RNAi.

Mower, Jeffrey P.; Wolfe, Kenneth H.; Fink, Gerald R.; Bartel, David P.

2013-01-01

143

Yeast expression platforms  

Microsoft Academic Search

Yeasts provide attractive expression platforms. They combine ease of genetic manipulations and the option for a simple fermentation\\u000a design of a microbial organism with the capabilities of an eukaryotic organism to secrete and to modify a protein according\\u000a to a general eukaryotic scheme. For platform applications, a range of yeast species has been developed during the last decades.\\u000a We present

Erik Böer; Gerhard Steinborn; Gotthard Kunze; Gerd Gellissen

2007-01-01

144

Pulmonary cavitation and skin lesions mimicking tuberculosis in a HIV negative patient caused by Sporothrix brasiliensis  

PubMed Central

A 32-year-old HIV negative male presented with multiple pulmonary cavitation and skin abscesses up to 15 cm in diameter mimicking tuberculosis. Sporothrix brasiliensis was isolated and patient responded well to amphotericin B followed by itraconazole, except the skin lesions that had to be surgical drained to obtain cure.

Orofino-Costa, Rosane; Unterstell, Natasha; Carlos Gripp, Alexandre; de Macedo, Priscila Marques; Brota, Arles; Dias, Emylli; de Melo Teixeira, Marcus; Felipe, Maria Sueli; Bernardes-Engemann, Andrea R; Lopes-Bezerra, Leila Maria

2013-01-01

145

Electric organ morphology and function in the lesser electric ray, Narcine brasiliensis  

Microsoft Academic Search

The lesser electric ray, Narcine brasiliensis, is a small, demersal ray capable of generating electricity through its main and accessory electric organs. Although closely related to the large piscivorous torpedo rays, it differs in size, habitat, and prey. Based on these differences, we hypothesized that the main electric organs are used for predator defense rather than feeding and that the

Laura J. Macesic; Stephen M. Kajiura

2009-01-01

146

Growth, photosynthetic performance and shade adaptation of rubber (Hevea brasiliensis) grown in natural shade  

Microsoft Academic Search

Summary We compared growth, photosynthetic perfor- mance and shade adaptation of rubber (Hevea brasiliensis Muell. Arg.) plants growing in natural shade (33, 55 and 77% reduction in incoming radiation) to control plants growing in full sunlight. Stem diameter and plant height, measured over a 15-month period, were greatest in plants grown in full sunlight, and both parameters decreased with increasing

A. M. W. K. SENEVIRATHNA; C. M. STIRLING; V. H. L. RODRIGO

147

IL-4R?-Associated Antigen Processing by B Cells Promotes Immunity in Nippostrongylus brasiliensis Infection  

PubMed Central

In this study, B cell function in protective TH2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4R? and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4R??/? mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4R? expressing B cells into naïve BALB/c mice, but not IL-4R? or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4+ T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88?/? B cells. These data suggest TLR dependent antigen processing by IL-4R?-responsive B cells producing IL-13 contribute significantly to CD4+ T cell-mediated protective immunity against N. brasiliensis infection.

Hoving, Jennifer C.; Nieuwenhuizen, Natalie; McSorley, Henry J.; Ndlovu, Hlumani; Bobat, Saeeda; Kimberg, Matti; Kirstein, Frank; Cutler, Anthony J.; DeWals, Benjamin; Cunningham, Adam F.; Brombacher, Frank

2013-01-01

148

Paludolactone: A new Eudesmanolide Lactone from Wedelia Paludosa Dc. (Acmela Brasiliensis)  

Microsoft Academic Search

Phytochemical investigation of the whole plant of Wedelia paludosa (Acmela brasiliensis) furnished a new eudesmanolide lactone, named paludolactone (2), in addition to the known eudesmanolide (1), stigmasterol, kaurenoic and oleanolic acids. H- and C-NMR, and MS spectroscopic and elemental analyses were used for the structural elucidation of these compounds.

Valdir Cechinel Filho; Luciana C. Block; Rosendo A. Yunes; Franco Delle Monache

2004-01-01

149

Black thread disease, control measures and yield stimulation in Hevea brasiliensis in Liberia  

Microsoft Academic Search

Described are investigations, carried out in 1963 to 1971 in Hevea brasiliensis at the Firestone Plantation at Harbel in Liberia. Studied was the tapping panel disease, black thread, caused by the fungus Phytophthora palmivora. The emphasis of the investigations was on control of the disease with the fungicide captafol (Difolatan). Another line of investigation was yield stimulation with 2,4-D (salts

J. Schreurs

1972-01-01

150

Paludolactone: a new eudesmanolide lactone from Wedelia paludosa DC. (Acmela brasiliensis).  

PubMed

Phytochemical investigation of the whole plant of Wedelia paludosa (Acmela brasiliensis) furnished a new eudesmanolide lactone, named paludolactone (2), in addition to the known eudesmanolide (1), stigmasterol, kaurenoic and oleanolic acids. 1H- and 13C-NMR, and MS spectroscopic and elemental analyses were used for the structural elucidation of these compounds. PMID:15248613

Cechinel Filho, Valdir; Block, Luciana C; Yunes, Rosendo A; Delle Monache, Franco

2004-10-01

151

Viral induced yeast apoptosis.  

PubMed

In an analogous system to mammals, induction of an apoptotic cell death programme (PCD) in yeast is not only restricted to various exogenous factors and stimuli, but can also be triggered by viral killer toxins and viral pathogens. In yeast, toxin secreting killer strains are frequently infected with double-stranded (ds)RNA viruses that are responsible for killer phenotype expression and toxin secretion in the infected host. In most cases, the viral toxins are either pore-forming proteins (such as K1, K2, and zygocin) that kill non-infected and sensitive yeast cells by disrupting cytoplasmic membrane function, or protein toxins (such as K28) that act in the nucleus by blocking DNA synthesis and subsequently causing a G1/S cell cycle arrest. Interestingly, while all these virus toxins cause necrotic cell death at high concentration, they trigger caspase- and ROS-mediated apoptosis at low-to-moderate concentration, indicating that even low toxin doses are deadly by triggering PCD in enemy cells. Remarkably, viral toxins are not solely responsible for cell death induction in vivo, as killer viruses themselves were shown to trigger apoptosis in non-infected yeast. Thus, as killer virus-infected and toxin secreting yeasts are effectively protected and immune to their own toxin, killer yeasts bear the intrinsic potential to dominate over time in their natural habitat. PMID:18291112

Schmitt, Manfred J; Reiter, Jochen

2008-07-01

152

Assessment of plant lectin antifungal potential against yeasts of major importance in medical mycology.  

PubMed

The search for new compounds with antifungal activity is accelerating due to rising yeast and fungal resistance to commonly prescribed drugs. Among the molecules being investigated, plant lectins can be highlighted. The present work shows the potential of six plant lectins which were tested in vitro against yeasts of medical importance, Candida albicans, Candida tropicalis, Candida parapsilosis, Cryptococcus gattii, Cryptococcus neoformans, Malassezia pachydermatis, Rhodotorula sp. and Trichosporon sp. Broth microdilution susceptibility testing was performed in accordance with standard protocols to evaluate antifungal activity. Minimum inhibitory concentration (MIC) was determined at 80% yeast growth inhibition, whereas the minimum fungicidal concentration (MFC) was evaluated after making the subcultures of each dilution. Only C. parapsilosis growth was inhibited by the lectins tested. Abelmoschus esculentus lectin showed the highest MIC (0.97 ?g ml(-1)). Lectins from Canavalia brasiliensis, Mucuna pruriens and Clitoria fairchildiana presented the highest MFC at (3.90 ?g ml(-1)). These results encourage further studies with wider yeast strain selections, and open new perspectives for the development of pharmacological molecules. PMID:23161017

Klafke, Gabriel Baracy; Moreira, Gustavo Marçal Schmitt Garcia; Monte, Leonardo Garcia; Pereira, Juliano Lacava; Brandolt, Tchana Martinez; Xavier, Melissa Orzechowski; Santi-Gadelha, Tatiane; Dellagostin, Odir Antonio; Pinto, Luciano da Silva

2013-02-01

153

Oxygen requirements of yeasts.  

PubMed Central

Type species of 75 yeast genera were examined for their ability to grow anaerobically in complex and mineral media. To define anaerobic conditions, we added a redox indicator, resazurin, to the media to determine low redox potentials. All strains tested were capable of fermenting glucose to ethanol in oxygen-limited shake-flask cultures, even those of species generally regarded as nonfermentative. However, only 23% of the yeast species tested grew under anaerobic conditions. A comparative study with a number of selected strains revealed that Saccharomyces cerevisiae stands out as a yeast capable of rapid growth at low redox potentials. Other yeasts, such as Torulaspora delbrueckii and Candida tropicalis, grew poorly mu max, 0.03 and 0.05 h-1, respectively) under anaerobic conditions in mineral medium supplemented with Tween 80 and ergosterol. The latter organisms grew rapidly under oxygen limitation and then displayed a high rate of alcoholic fermentation. It can be concluded that these yeasts have hitherto-unidentified oxygen requirements for growth. Images

Visser, W; Scheffers, W A; Batenburg-van der Vegte, W H; van Dijken, J P

1990-01-01

154

Mapping Yeast Transcriptional Networks  

PubMed Central

The term “transcriptional network” refers to the mechanism(s) that underlies coordinated expression of genes, typically involving transcription factors (TFs) binding to the promoters of multiple genes, and individual genes controlled by multiple TFs. A multitude of studies in the last two decades have aimed to map and characterize transcriptional networks in the yeast Saccharomyces cerevisiae. We review the methodologies and accomplishments of these studies, as well as challenges we now face. For most yeast TFs, data have been collected on their sequence preferences, in vivo promoter occupancy, and gene expression profiles in deletion mutants. These systematic studies have led to the identification of new regulators of numerous cellular functions and shed light on the overall organization of yeast gene regulation. However, many yeast TFs appear to be inactive under standard laboratory growth conditions, and many of the available data were collected using techniques that have since been improved. Perhaps as a consequence, comprehensive and accurate mapping among TF sequence preferences, promoter binding, and gene expression remains an open challenge. We propose that the time is ripe for renewed systematic efforts toward a complete mapping of yeast transcriptional regulatory mechanisms.

Hughes, Timothy R.; de Boer, Carl G.

2013-01-01

155

21 CFR 172.896 - Dried yeasts.  

Code of Federal Regulations, 2013 CFR

...172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis ) and dried torula yeast (Candida utilis ) may be safely used in food provided the total folic acid content of the yeast does not exceed 0.04 milligram...

2013-04-01

156

Yeast killer systems.  

PubMed Central

The killer phenomenon in yeasts has been revealed to be a multicentric model for molecular biologists, virologists, phytopathologists, epidemiologists, industrial and medical microbiologists, mycologists, and pharmacologists. The surprisingly widespread occurrence of the killer phenomenon among taxonomically unrelated microorganisms, including prokaryotic and eukaryotic pathogens, has engendered a new interest in its biological significance as well as its theoretical and practical applications. The search for therapeutic opportunities by using yeast killer systems has conceptually opened new avenues for the prevention and control of life-threatening fungal diseases through the idiotypic network that is apparently exploited by the immune system in the course of natural infections. In this review, the biology, ecology, epidemiology, therapeutics, serology, and idiotypy of yeast killer systems are discussed.

Magliani, W; Conti, S; Gerloni, M; Bertolotti, D; Polonelli, L

1997-01-01

157

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

2008-02-28

158

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

159

Differences in Cell Morphometry, Cell Wall Topography and Gp70 Expression Correlate with the Virulence of Sporothrix brasiliensis Clinical Isolates  

PubMed Central

Sporotrichosis is a chronic infectious disease affecting both humans and animals. For many years, this subcutaneous mycosis had been attributed to a single etiological agent; however, it is now known that this taxon consists of a complex of at least four pathogenic species, including Sporothrix schenckii and Sporothrix brasiliensis. Gp70 was previously shown to be an important antigen and adhesin expressed on the fungal cell surface and may have a key role in immunomodulation and host response. The aim of this work was to study the virulence, morphometry, cell surface topology and gp70 expression of clinical isolates of S. brasiliensis compared with two reference strains of S. schenckii. Several clinical isolates related to severe human cases or associated with the Brazilian zoonotic outbreak of sporotrichosis were genotyped and clustered as S. brasiliensis. Interestingly, in a murine subcutaneous model of sporotrichosis, these isolates showed a higher virulence profile compared with S. schenckii. A single S. brasiliensis isolate from an HIV-positive patient not only showed lower virulence but also presented differences in cell morphometry, cell wall topography and abundant gp70 expression compared with the virulent isolates. In contrast, the highly virulent S. brasiliensis isolates showed reduced levels of cell wall gp70. These observations were confirmed by the topographical location of the gp70 antigen using immunoelectromicroscopy in both species. In addition, the gp70 molecule was sequenced and identified using mass spectrometry, and the sequenced peptides were aligned into predicted proteins using Blastp with the S. schenckii and S. brasiliensis genomes.

Castro, Rafaela A.; Kubitschek-Barreira, Paula H.; Teixeira, Pedro A. C.; Sanches, Glenda F.; Teixeira, Marcus M.; Quintella, Leonardo P.; Almeida, Sandro R.; Costa, Rosane O.; Camargo, Zoilo P.; Felipe, Maria S. S.; de Souza, Wanderley; Lopes-Bezerra, Leila M.

2013-01-01

160

Vaginal Yeast Infections (For Parents)  

MedlinePLUS

... a common infection caused by a yeast called candida albicans (a type of fungus). Yeast infections usually ... the vagina, it is known as vulvovaginal candidiasis . Candida can overgrow for many reasons. Stress, pregnancy, and ...

161

L-arabinose fermenting yeast  

DOEpatents

An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. Methods of producing ethanol include utilizing these modified yeast strains. ##STR00001##

Zhang, Min (Lakewood, CO); Singh, Arjun (Lakewood, CO); Knoshaug, Eric (Golden, CO); Franden, Mary Ann (Centennial, CO); Jarvis, Eric (Boulder, CO); Suominen, Pirkko (Maple Grove, MN)

2010-12-07

162

A Common Caatinga Cactus, Pilosocereus gounellei, is an Important Ecotope of Wild Triatoma brasiliensis Populations in the Jaguaribe Valley of Northeastern Brazil.  

PubMed

Triatoma brasiliensis is the most important vector of Chagas disease in the Caatinga eco-region of northeastern Brazil. Wild T. brasiliensis populations have been reported only from rocky outcrops. However, this species frequently infests/re-infests houses in rock-free sedimentary lowlands. We therefore hypothesized that it should also occupy other natural ecotopes. We show that a common Caatinga cactus, Pilosocereus gounellei, locally known as xiquexique, often harbors T. brasiliensis breeding colonies apparently associated with rodents (n = 44 cacti, infestation rate = 47.7%, 157 bugs captured). Our findings suggest that infested cacti might be involved in house re-infestation by T. brasiliensis in the Caatinga region. PMID:24710611

Valença-Barbosa, Carolina; Lima, Marli M; Sarquis, Otília; Bezerra, Claudia M; Abad-Franch, Fernando

2014-06-01

163

Evaluation of YeastIdent and Uni-Yeast-Tek yeast identification systems.  

PubMed Central

The accuracy of the new API YeastIdent system and the Flow Laboratories Uni-Yeast-Tek identification kit with an expanded data base was evaluated in comparison to the API 20C yeast identification system by three laboratories. A total of 489 test isolates were used, biased toward yeasts commonly encountered in clinical specimens. Isolates not in a system's data base were not counted in the evaluation of that system. For isolates in their data base, YeastIdent was 55% accurate and Uni-Yeast-Tek was 40% accurate. By the manufacturer's criteria of reliable identification without additional tests, both systems failed to identify many common and uncommon species. The limited number of substrates and difficulties in assessing results obtained with 11 of the API YeastIdent substrates and apparent errors in the expanded Uni-Yeast-Tek data base appeared to be major factors limiting the accuracy of these systems.

Salkin, I F; Land, G A; Hurd, N J; Goldson, P R; McGinnis, M R

1987-01-01

164

Mutagen testing with yeast.  

PubMed

This article deals primarily with the practical aspects of mutagen testing with yeast. Equipment necessary for a laboratory where mutagen testing with yeast is performed, and the most commonly used media, are listed. Some general procedures are described and, finally, for those who have little experience with work of this kind, a precise protocol is given for an experiment with stationary phase cells of the strain D7 of Saccharomyces cerevisiae using the heteroallelic ade2 system as the genetic endpoint. Some experimental data were obtained by students following this protocol using the direct-acting mutagen ethyl methanesulfonate (EMS); these data are discussed and analyzed. More details on the various genetic endpoints available in numerous yeast strains and on the interpretation of dose-dependence data, as well as an extended list of yeast literature, can be found in an article by Eckardt and von Borstel in this volume. Further technical advice is provided in our references to Zimmermann (1975), von Borstel (1981), and Zimmermann et al. (1984). PMID:3904715

Eckardt, F; Siede, W

1985-01-01

165

Anti-proliferation effect of Hevea brasiliensis latex B-serum on human breast epithelial cells.  

PubMed

The rubber tree (Hevea brasiliensis) extracts are becoming increasingly visible in pharmaceutical and therapeutical research. The present study is aimed at examining the specific anti-proliferation property of H. brasiliensis latex B-serum sub-fractions against human breast cancer epithelial cell lines MCF-7 and MDA-MB231. The results showed that the latex whole B-serum and DBP sub-fraction exerted a specific anti-proliferation activity against cancer-origin cells MDA-MB231 but had little effect on non-cancer-origin cells. On the other hand, the anti-proliferative activity was diminished in the pre-heated B-serum fractions. With the low toxicity that the B-serum demonstrated previously in Brine Shrimp Lethality Test (BSLT), the present results suggest the potential use of the B-serum sub-fractions in cancer treatment. PMID:22713955

Lee, Yang Kok; Lay, Lam Kit; Mahsufi, Mansor Sharif; Guan, Teoh Siang; Elumalai, Sunderasan; Thong, Ong Ming

2012-07-01

166

L-arabinose fermenting yeast  

DOEpatents

An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

2013-02-12

167

Interleukin-4-Promoted T Helper 2 Responses Enhance Nippostrongylus brasiliensis-Induced Pulmonary Pathology?  

PubMed Central

The role of CD4+ T-cell interleukin-4 (IL-4) receptor alpha (IL-4R?) expression in T helper 2 (TH2) immune responses has not been defined. To examine this role, we infected CD4+ T-cell IL-4R? knockout (KO) mice with the parasitic nematode Nippostrongylus brasiliensis, which induces strong host TH2 responses. Although N. brasiliensis expulsion was not affected in CD4+ T-cell IL-4R? KO mice, the associated lung pathology was reduced. Infected CD4+ T-cell IL-4R? KO mice showed abrogation of airway mucus production. Furthermore, CD4+ T-cell IL-4R? KO mouse lungs contained reduced numbers of lymphocytes and eosinophils. Restimulation of pulmonary region-associated T-cell populations showed that TH2 cytokine responses were disrupted. Secretion of IL-4, but not secretion of IL-13 or IL-5, from mediastinal lymph node CD4+ T cells was reduced in infected CD4+ T-cell IL-4R? KO mice. Restimulation of tissue-derived CD4+ T cells resulted in equivalent levels of IL-4 and IL-13 on day 7 postinfection (p.i.) in control and CD4+ T-cell IL-4R? KO mice. By day 10 p.i. the TH2 cytokine levels had significantly declined in CD4+ T-cell IL-4R? KO mice. Restimulation with N. brasiliensis antigen of total lung cell populations and populations with CD4+ T cells depleted showed that CD4+ T cells were a key TH2 cytokine source. These data demonstrated that CD4+ T-cell IL-4 responsiveness facilitates eosinophil and lymphocyte recruitment, lymphocyte localization, and TH2 cytokine production in the allergic pathology associated with N. brasiliensis infections.

Mearns, Helen; Horsnell, William G. C.; Hoving, J. Claire; Dewals, Benjamin; Cutler, Antony J.; Kirstein, Frank; Myburgh, Elmarie; Arendse, Berenice; Brombacher, Frank

2008-01-01

168

Interleukin-4-promoted T helper 2 responses enhance Nippostrongylus brasiliensis-induced pulmonary pathology.  

PubMed

The role of CD4(+) T-cell interleukin-4 (IL-4) receptor alpha (IL-4Ralpha) expression in T helper 2 (TH2) immune responses has not been defined. To examine this role, we infected CD4(+) T-cell IL-4Ralpha knockout (KO) mice with the parasitic nematode Nippostrongylus brasiliensis, which induces strong host TH2 responses. Although N. brasiliensis expulsion was not affected in CD4(+) T-cell IL-4Ralpha KO mice, the associated lung pathology was reduced. Infected CD4(+) T-cell IL-4Ralpha KO mice showed abrogation of airway mucus production. Furthermore, CD4(+) T-cell IL-4Ralpha KO mouse lungs contained reduced numbers of lymphocytes and eosinophils. Restimulation of pulmonary region-associated T-cell populations showed that TH2 cytokine responses were disrupted. Secretion of IL-4, but not secretion of IL-13 or IL-5, from mediastinal lymph node CD4(+) T cells was reduced in infected CD4(+) T-cell IL-4Ralpha KO mice. Restimulation of tissue-derived CD4(+) T cells resulted in equivalent levels of IL-4 and IL-13 on day 7 postinfection (p.i.) in control and CD4(+) T-cell IL-4Ralpha KO mice. By day 10 p.i. the TH2 cytokine levels had significantly declined in CD4(+) T-cell IL-4Ralpha KO mice. Restimulation with N. brasiliensis antigen of total lung cell populations and populations with CD4(+) T cells depleted showed that CD4(+) T cells were a key TH2 cytokine source. These data demonstrated that CD4(+) T-cell IL-4 responsiveness facilitates eosinophil and lymphocyte recruitment, lymphocyte localization, and TH2 cytokine production in the allergic pathology associated with N. brasiliensis infections. PMID:18809669

Mearns, Helen; Horsnell, William G C; Hoving, J Claire; Dewals, Benjamin; Cutler, Antony J; Kirstein, Frank; Myburgh, Elmarie; Arendse, Berenice; Brombacher, Frank

2008-12-01

169

Crystallization and preliminary X-ray diffraction studies of a hydroxynitrile lyase from Hevea brasiliensis.  

PubMed

Crystals of the hydroxynitrile lyase from Hevea brasiliensis overexpressed in Pichia pastoris have been obtained by the hanging-drop technique at 294 K with ammonium sulfate and PEG 400 as precipitants. The crystals belong to the orthorhombic space group C222(1) with cell dimensions of a = 47.6, b = 106.8 and c = 128.2 A. The crystals diffract to about 2.5 A resolution on a rotating-anode X-ray source. PMID:15299689

Wagner, U G; Schall, M; Hasslacher, M; Hayn, M; Griengl, H; Schwab, H; Kratky, C

1996-05-01

170

Cloning and expression of the gene encoding solanesyl diphosphate synthase from Hevea brasiliensis  

Microsoft Academic Search

Summary Plastoquinones play important roles as electron carriers in the light-dependent reactions of photosynthesis and also as a cofactor of phytoene desaturation in the synthesis of carotenoid. A plastoquinone-9 (PQ-9) was identified in Frey-Wyssling organelles of fresh rubber latex from Hevea brasiliensis. This indicates that a Hevea solanesyl diphosphate synthase (HbSDS) must be present for the synthesis of the C45

Atiphon Phatthiya; Seiji Takahashi; Nopphakaew Chareonthiphakorn; Tanetoshi Koyama; Dhirayos Wititsuwannakul; Rapepun Wititsuwannakul

2007-01-01

171

Contributions of weather variables for specific adaptation of rubber tree (Hevea brasiliensis Muell.- Arg) clones  

Microsoft Academic Search

The specific adaptation of 15 rubber tree (Hevea brasiliensis) clones was assessed by analyzing yield during a normal year (1997-98) and a year (1998-99) in which the yield was exceptional. Differences in yield in response to changes in weather conditions over the years were evident with clones RRII 203, RRIM 703, PB 5\\/51 and PB 235 which all exhibited a

P. M. Priyadarshan

2003-01-01

172

Population growth of Mexican free-tailed bats ( Tadarida brasiliensis mexicana ) predates human agricultural activity  

Microsoft Academic Search

Background  Human activities, such as agriculture, hunting, and habitat modification, exert a significant effect on native species. Although\\u000a many species have suffered population declines, increased population fragmentation, or even extinction in connection with\\u000a these human impacts, others seem to have benefitted from human modification of their habitat. Here we examine whether population\\u000a growth in an insectivorous bat (Tadarida brasiliensis mexicana) can

Amy L Russell; Murray P Cox; Veronica A Brown; Gary F McCracken

2011-01-01

173

Cryopreservation of nucellar cells of navel orange ( Citrus sinensis Osb. var. brasiliensis Tanaka) by vitrification  

Microsoft Academic Search

The nucellar cells of navel orange(Citrus sinensis Osb. var. brasiliensis Tanaka) were successfully cryopreserved by vitrification. In this method, cells were sufficiently dehydrated with highly concentrated cryoprotective solution(PVS2) prior to direct plunge in liquid nitrogen. The PVS2 contains(w\\/v) 30% glycerol, 15% ethylene glycol and 15% DMSO in Murashige-Tucker medium(MT) containing 0.15 M sucrose. Cells were treated with 60% PVS2 at

A. Sakai; S. Kobayashi; I. Oiyama

1990-01-01

174

Lectin from Canavalia brasiliensis (MART.). isolation, characterization and behavior during germination  

Microsoft Academic Search

A lectin was isolated fromCanavalia brasiliensis Mart. seeds by combining solubility fractionation with affinity chromatography on Sephadex G-50. The lectin showed a carbohydrate\\u000a specificity for D-mannose (D-glucose) binding and a requirement for Ca2+ and Mn2+. All the hemagglutinating activity was found in the cotyledons and the presence of the lectin was followed during the first\\u000a 15 days of plant germination,

R. A. Moreira; B. S. Gavada

1984-01-01

175

Antifungal activity of fractions and two pure compounds of flowers from Wedelia paludosa (Acmela brasiliensis) (Asteraceae).  

PubMed

Wedelia paludosa (Acmela brasiliensis) (Asteraceae), a traditionally used native Brazilian medicinal plant, showed antifungal activity against dermatophytes in dilution tests. The hexane, dichloromethane and butanol fractions displayed activity against Epidermophyton floccosum, Trichophyton rubrum and Trichophyton mentagrophytes, with minimal inhibitory concentrations between 250 and 1000 microg/mL. Two pure compounds, identified as kaurenoic acid (1) and luteolin (2), also showed activity against these dermatophytes. PMID:12967035

Sartori, M R K; Pretto, J B; Cruz, A B; Bresciani, L F V; Yunes, R A; Sortino, M; Zacchino, S A; Cechinel, V Filho

2003-08-01

176

Seasonal variation of kaurenoic acid, a hypoglycemic diterpene present in Wedelia paludosa (Acmela brasiliensis) (Asteraceae).  

PubMed

We evaluated the variation of the concentration of kaurenoic acid (1), which is a bioactive diterpene, in leaves, flowers, stems and roots from Wedelia paludosa (Acmela brasiliensis) for different seasons using the HRGC/FID method. The results indicated that the concentration of 1 is higher in the roots and stems during the autumn. The pharmacological results suggested that kaurenoic acid is responsible, at least in part, for the hypoglycemic potential detected in this plant. PMID:15241932

Bresciani, Louisiane Faccio V; Yunes, Rosendo Augusto; Bürger, Cristiani; De Oliveira, Luis Eduardo; Bóf, Kauê Leal; Cechinel-Filho, Valdir

2004-01-01

177

Actinomycotic mycetoma due to Nocardia brasiliensis in a case of leprosy.  

PubMed

Various bacterial and fungal infections associated with non-healing ulcers in cases of leprosy have been reported (G Ebenzer et al, 2000, Rama Ramani et al, 1990). There are no reports of mycetoma associated with leprosy patients in the literature. We report here a case of actinomycotic mycetoma due to Nocardia brasiliensis associated with the non-healing plantar ulcer of a leprosy patient. PMID:11840598

Kulkarni, R B; Patil, R T; Praveena, S

2001-01-01

178

The sialotranscriptome of the blood-sucking bug Triatoma brasiliensis (Hemiptera, Triatominae)  

PubMed Central

Triatoma brasiliensis is the most important autochthon vector of Trypanosoma cruzi in Brazil, where it is widely distributed in the semiarid areas of the Northeast. In order to advance the knowledge of the salivary biomolecules of Triatominae, a salivary gland cDNA library of T. brasiliensis was mass sequenced and analyzed. Polypeptides were sequenced by HPLC/Edman degradation experiments. 1,712 cDNA sequences were obtained and grouped in 786 clusters. The housekeeping category had 24.4% and 17.8% of the clusters and sequences, respectively. The putatively secreted category contained 47.1% of the clusters and 68.2% of the sequences. Finally, 28.5% of the clusters, containing 14% of all sequences, were classified as unknown. The sialoma of T. brasiliensis showed a high amount and great variety of different lipocalins (93.8% of secreted proteins). Remarkably, a great number of serine proteases that were not observed in previous blood-sucking sialotranscriptomes were found. Nine Kazal peptides were identified, among them one with high homology to the tabanid vasodilator vasotab, suggesting that the Triatoma vasodilator could be a Kazal protein.

Santos, Adriana; Ribeiro, Jose Marcos C.; Lehane, Michael J.; Gontijo, Nelder Figueiredo; Veloso, Artur Botelho; Sant'Anna, Mauricio R.V.; Araujo, Ricardo Nascimento; Grisard, Edmundo C.; Pereira, Marcos Horacio

2007-01-01

179

Nocardia brasiliensis Induces Formation of Foamy Macrophages and Dendritic Cells In Vitro and In Vivo  

PubMed Central

Foamy cells have been described in various infectious diseases, for example in actinomycetoma induced by Nocardia brasiliensis. These cells are generally considered to be macrophages, although they present dendritic cell (DC)-specific surface markers. In this study, we determined and confirmed the lineage of possible precursors of foamy cells in vitro and in vivo using an experimental actinomycetoma model in BALB/c mice. Bone marrow-derived macrophages (BMDM) or DC (BMDC) were infected in vitro with N. brasiliensis or labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE). Both, macrophages and DC, differentiated into foamy cells after in vitro infection. CFSE-labeled BMDM or BMDC were tested for phagocytosis and CD11c/CD11b receptors markers expression before being transferred into the actinomycetoma lesion site of infected mice. In vivo studies showed that BMDM and BMDC were traced at the site where foamy cells are present in the experimental actinomycetoma. Interestingly, many of the transferred BMDM and BMDC were stained with the lipid-droplet fluorophore Nile Red. In conclusion, macrophages and DC cells can be differentiated into foamy cells in vitro and in vivo during N. brasiliensis infection.

Meester, Irene; Rosas-Taraco, Adrian Geovanni; Salinas-Carmona, Mario Cesar

2014-01-01

180

Extracellular Polysaccharides Produced by Yeasts and Yeast-Like Fungi  

NASA Astrophysics Data System (ADS)

Several yeasts and yeast-like fungi are known to produce extracellular polysaccharides. Most of these contain D-mannose, either alone or in combination with other sugars or phosphate. A large chemical and structural variability is found between yeast species and even among different strains. The types of polymers that are synthesized can be chemically characterized as mannans, glucans, phosphoman-nans, galactomannans, glucomannans and glucuronoxylomannans. Despite these differences, almost all of the yeast exopolysaccharides display some sort of biological activity. Some of them have already applications in chemistry, pharmacy, cosmetics or as probiotic. Furthermore, some yeast exopolysaccharides, such as pullulan, exhibit specific physico-chemical and rheological properties, making them useful in a wide range of technical applications. A survey is given here of the production, the characteristics and the application potential of currently well studied yeast extracellular polysaccharides.

van Bogaert, Inge N. A.; de Maeseneire, Sofie L.; Vandamme, Erick J.

181

Ornithodoros brasiliensis (mouro tick) salivary gland homogenates inhibit in vivo wound healing and in vitro endothelial cell proliferation.  

PubMed

Ornithodoros brasiliensis is a nidicolous tick only found in the southern Brazilian highlands region. O. brasiliensis parasitism is frequently associated with toxicosis syndrome, which can lead to severe reactions, ranging from local pruritus and pain to systemic disturbances both in humans and dogs. One of the most frequent findings associated with an O. brasiliensis bite is a slow healing lesion at the site of tick attachment, which can take several weeks to heal. This work tested the hypothesis that an O. brasiliensis salivary gland homogenate is able to modulate the skin wound-healing process in vivo, using a model of excisional skin lesion in rats, which are divided into two groups: (1) control group and (2) treated group, which topically received salivary gland homogenate equivalent to the protein amount of one whole salivary gland (?5 ?g protein). The hypothesis that O. brasiliensis salivary gland homogenates interfere with endothelial cell proliferation, a key role phenomenon in wound healing, was also tested. O. brasiliensis salivary gland homogenates significantly delay skin wound healing. The time to full healing of skin lesions in control rats was 15 days, contrasting with 24 days in rats topically treated with O. brasiliensis salivary gland homogenates. The calculated HT50 (healing time to recover 50% of the wound area) for control groups was 3.6 days (95% CI, 3.2-3.9) and for salivary gland treated rats was 7.7 days (95% CI, 7.0-8.4). Salivary gland homogenates have a strong cytotoxic activity on cultured endothelial cells (LC50, 13.6 mg/ml). Also, at sublethal concentrations (?3 mg/ml), salivary gland homogenates have a remarkable anti-proliferative activity (IC50 0.7 mg/ml) on endothelial cells, equivalent to ?0.03 salivary gland pairs, an activity which seems to be much greater than reported for any other tick species. This is the first report about the biological activities of O. brasiliensis salivary compounds and provides the first in vivo evidence to support the concept of wound-healing modulation by tick salivary secretions. Results shown here contribute to an understanding of O. brasiliensis tick toxicosis syndrome, and also increase our knowledge of tick salivary bioactive compounds. PMID:23397378

Reck, José; Marks, Fernanda S; Termignoni, Carlos; Guimarães, Jorge A; Martins, João Ricardo

2013-04-01

182

Yeast-Hyphal Dimorphism  

Microsoft Academic Search

All fungi have some capacity to grow in two basic morphological forms — spheres and tubes — therefore it could be argued that\\u000a they are all, to some extent, dimorphic. For many filamentous fungi spherical growth may only be expressed during the formation\\u000a of spores and many yeast-like fungi have only the remnants of a true filamentous growth habit. However,

N. A. R. Gow

183

Yeast Colony Embedding Method  

PubMed Central

Patterning of different cell types in embryos is a key mechanism in metazoan development. Communities of microorganisms, such as colonies and biofilms also display patterns of cell types. For example, in the yeast S. cerevisiae, sporulated cells and pseudohyphal cells are not uniformly distributed in colonies. The functional importance of patterning and the molecular mechanisms that underlie these patterns are still poorly understood. One challenge with respect to investigating patterns of cell types in fungal colonies is that unlike metazoan tissue, cells in colonies are relatively weakly attached to one another. In particular, fungal colonies do not contain the same extensive level of extracellular matrix found in most tissues . Here we report on a method for embedding and sectioning yeast colonies that reveals the interior patterns of cell types in these colonies. The method can be used to prepare thick sections (0.5 ?) useful for light microscopy and thin sections (0.1 ?) suitable for transmission electron microscopy. Asci and pseudohyphal cells can easily be distinguished from ovoid yeast cells by light microscopy , while the interior structure of these cells can be visualized by EM. The method is based on surrounding colonies with agar, infiltrating them with Spurr's medium, and then sectioning. Colonies with a diameter in the range of 1-2 mm are suitable for this protocol. In addition to visualizing the interior of colonies, the method allows visualization of the region of the colony that invades the underlying agar.

Piccirillo, Sarah; Honigberg, Saul M.

2011-01-01

184

Effects of polysaccharide from fruiting bodies of Agaricus bisporus, Agaricus brasiliensis, and Phellinus linteus on alcoholic liver injury.  

PubMed

In the present study, the curative effects of crude polysaccharides (PSs) from mushrooms on the symptoms of alcoholic liver injury were investigated. PSs from Agaricus bisporus, Agaricus brasiliensis, and Phellinus linteus fruiting bodies were administered by gavage at levels of 100?mg per kg body weight per day for 7?d after the onset of the disease. The caspase-3 activity, mitochondrial membrane potential, mitochondrial outer membrane integrity of the liver tissues of sacrificed rats, and the serum alanine aminotransferase (ALT) levels were determined. In addition, light and transmission electron microscope (TEM) studies were performed for histopathological and cytological evaluations on liver sections. PSs from A. brasiliensis decreased ALT level and mitochondrial membrane potential and increased the outer membrane integrity; microscopic examinations also revealed normal hepatocytes and tissue. On the basis of our data, it can be argued that crude PSs from Agaricus brasiliensis have therapeutic potential for alcoholic liver injury. PMID:24392995

Uyanoglu, Mustafa; Canbek, Mediha; van Griensven, Leo J L D; Yamac, Mustafa; Senturk, Hakan; Kartkaya, Kaz?m; Oglakc?, Aysegul; Turgak, Ozge; Kanbak, Gungor

2014-06-01

185

Diet and helminths of Enyalius brasiliensis (Lacertilia, Iguania, Leiosauridae) in an Atlantic Rainforest remnant in southeastern Brazil.  

PubMed

Our study aimed to add information about the diet and endoparasites of Enyalius brasiliensis from an Atlantic Rainforest remnant in the state of Rio de Janeiro, southeastern Brazil. Regarding diet, E. brasiliensis consumed arthropods, with caterpillars and beetles being the most important preys. Regarding helminth parasites, overall prevalence was low (9.5%), with 238 nematodes of the genus Physaloptera found in the stomach of one specimen and one nematode of the genus Rhabdias inside the lung of another. Our results corroborate the observations of previous studies that indicate that lizards of the genus Enyalius tend to feed mainly on relatively large-bodied arthropods and to harbour depauperate endoparasite fauna. PMID:25055102

Dorigo, Ta; Maia-Carneiro, T; Almeida-Gomes, M; Siqueira, Cc; Vrcibradic, D; Van Sluys, M; Rocha, Cfd

2014-02-01

186

In-depth proteome analysis of the rubber particle of Hevea brasiliensis (para rubber tree).  

PubMed

The rubber particle is a special organelle in which natural rubber is synthesised and stored in the laticifers of Hevea brasiliensis. To better understand the biological functions of rubber particles and to identify the candidate rubber biosynthesis-related proteins, a comprehensive proteome analysis was performed on H. brasiliensis rubber particles using shotgun tandem mass spectrometry profiling approaches-resulting in a thorough report on the rubber particle proteins. A total of 186 rubber particle proteins were identified, with a range in relative molecular mass of 3.9-194.2 kDa and in isoelectric point values of 4.0-11.2. The rubber particle proteins were analysed for gene ontology and could be categorised into eight major groups according to their functions: including rubber biosynthesis, stress- or defence-related responses, protein processing and folding, signal transduction and cellular transport. In addition to well-known rubber biosynthesis-related proteins such as rubber elongation factor (REF), small rubber particle protein (SRPP) and cis-prenyl transferase (CPT), many proteins were firstly identified to be on the rubber particles, including cyclophilin, phospholipase D, cytochrome P450, small GTP-binding protein, clathrin, eukaryotic translation initiation factor, annexin, ABC transporter, translationally controlled tumour protein, ubiquitin-conjugating enzymes, and several homologues of REF, SRPP and CPT. A procedure of multiple reaction monitoring was established for further protein validation. This comprehensive proteome data of rubber particles would facilitate investigation into molecular mechanisms of biogenesis, self-homeostasis and rubber biosynthesis of the rubber particle, and might serve as valuable biomarkers in molecular breeding studies of H. brasiliensis and other alternative rubber-producing species. PMID:23553221

Dai, Longjun; Kang, Guijuan; Li, Yu; Nie, Zhiyi; Duan, Cuifang; Zeng, Rizhong

2013-05-01

187

Decrease of virulence for BALB/c mice produced by continuous subculturing of Nocardia brasiliensis  

PubMed Central

Background Subculturing has been extensively used to attenuate human pathogens. In this work we studied the effect of continuous subculturing of Nocardia brasiliensis HUJEG-1 on virulence in a murine model. Methods Nocardia brasiliensis HUJEG-1 was subcultured up to 130 times on brain heart infusion over four years. BALB/c mice were inoculated in the right foot pad with the bacteria subcultured 0, 40, 80, 100 and 130 times (T0, T40, T80 T100 and T130). The induction of resistance was tested by using T130 to inoculate a group of mice followed by challenge with T0 12 weeks later. Biopsies were taken from the newly infected foot-pad and immunostained with antibodies against CD4, CD8 and CD14 in order to analyze the in situ immunological changes. Results When using T40, T80 T100 and T130 as inoculums we observed lesions in 10, 5, 0 and 0 percent of the animals, respectively, at the end of 12 weeks. In contrast, their controls produced mycetoma in 80, 80, 70 and 60% of the inoculated animals. When studying the protection of T130, we observed a partial resistance to the infection. Immunostaining revealed an intense CD4+ lymphocytic and macrophage infiltrate in healing lesions. Conclusions After 130 in vitro passages of N. brasiliensis HUJEG-1 a severe decrease in its virulence was observed. Immunization of BALB/c mice, with these attenuated cells, produced a state of partial resistance to infection with the non-subcultured isolate.

2011-01-01

188

Yeast interactions and wine flavour  

Microsoft Academic Search

Wine is the product of complex interactions between fungi, yeasts and bacteria that commence in the vineyard and continue throughout the fermentation process until packaging. Although grape cultivar and cultivation provide the foundations of wine flavour, microorganisms, especially yeasts, impact on the subtlety and individuality of the flavour response. Consequently, it is important to identify and understand the ecological interactions

Graham H. Fleet

2003-01-01

189

Yeast as a screening tool  

Microsoft Academic Search

The versatile genetic malleability of yeast, and the high degree of conservation between its cellular processes and those of human cells, have made it the model of choice for pioneering research in molecular and cell biology over the past four decades. These character- istics of yeast, taken together with technical advan- tages such as simple growth conditions, rapid cell division

Alcide Barberis; Tea Gunde; Catherine Berset; Stephan Audetat; Urs Lüthi

2005-01-01

190

Monitoring polyglutamine toxicity in yeast.  

PubMed

Experiments in yeast have significantly contributed to our understanding of general aspects of biochemistry, genetics, and cell biology. Yeast models have also delivered deep insights in to the molecular mechanism underpinning human diseases, including neurodegenerative diseases. Many neurodegenerative diseases are associated with the conversion of a protein from a normal and benign conformation into a disease-associated and toxic conformation - a process called protein misfolding. The misfolding of proteins with abnormally expanded polyglutamine (polyQ) regions causes several neurodegenerative diseases, such as Huntington's disease and the Spinocerebellar Ataxias. Yeast cells expressing polyQ expansion proteins recapitulate polyQ length-dependent aggregation and toxicity, which are hallmarks of all polyQ-expansion diseases. The identification of modifiers of polyQ toxicity in yeast revealed molecular mechanisms and cellular pathways that contribute to polyQ toxicity. Notably, several of these findings in yeast were reproduced in other model organisms and in human patients, indicating the validity of the yeast polyQ model. Here, we describe different expression systems for polyQ-expansion proteins in yeast and we outline experimental protocols to reliably and quantitatively monitor polyQ toxicity in yeast. PMID:21144902

Duennwald, Martin L

2011-03-01

191

Modelling the yeast interactome.  

PubMed

The topology behind biological interaction networks has been studied for over a decade. Yet, there is no definite agreement on the theoretical models which best describe protein-protein interaction (PPI) networks. Such models are critical to quantifying the significance of any empirical observation regarding those networks. Here, we perform a comprehensive analysis of yeast PPI networks in order to gain insights into their topology and its dependency on interaction-screening technology. We find that: (1) interaction-detection technology has little effect on the topology of PPI networks; (2) topology of these interaction networks differs in organisms with different cellular complexity (human and yeast); (3) clear topological difference is present between PPI networks, their functional sub-modules, and their inter-functional "linkers"; (4) high confidence PPI networks have more "geometrical" topology compared to predicted, incomplete, or noisy PPI networks; and (5) inter-functional "linker" proteins serve as mediators in signal transduction, transport, regulation and organisational cellular processes. PMID:24589662

Janji?, Vuk; Sharan, Roded; Pržulj, Nataša

2014-01-01

192

Red yeast rice for dysipidemia.  

PubMed

Red yeast rice is an ancient Chinese food product that contains monacolins, chemical substances that are similar to statins in their mechanisms of action and lipid lowering properties. Several studies have found red yeast rice to be moderately effective at improving the lipid profile, particularly for lowering the low-density lipoprotein cholesterol levels. One large randomized controlled study from China found that red yeast rice significantly improved risk of major adverse cardiovascular events and overall survival in patients following myocardial infarction. Thus, red yeast rice is a potentially useful over-the-counter cholesterol-lowering agent. However, many red yeast rice formulations are non-standardized and unregulated food supplements, and there is a need for further research and regulation of production. PMID:24003656

Shamim, Shariq; Al Badarin, Firas J; DiNicolantonio, James J; Lavie, Carl J; O'Keefe, James H

2013-01-01

193

Programmed nuclear destruction in yeast  

PubMed Central

Studies of the budding yeast Saccharomyces cerevisiae have provided many of the most important insights into the mechanisms of autophagy, which are common to all eukaryotes. However, investigation of yeast self-destruction pathways, including autophagy and programmed cell death, has been almost exclusively restricted to cells undergoing vegetative growth, leaving very little exploration of their functions during developmental transitions in the yeast life cycle. We have recently discovered that whole nuclei are subject to programmed destruction during yeast gametogenesis. Programmed nuclear destruction (PND) possesses characteristics of apoptosis in the form of DNA cleavage by endonuclease G, and involves bulk protein turnover through an unusual autophagic pathway involving lysis of the vacuole rather than delivery of components to it through macroautophagy. We thus illuminate an example of developmentally programmed cellular “self-eating” in yeast, which is associated with the rupture of a lytic organelle, reminiscent of programmed cell death mechanisms in plants and animals.

Eastwood, Michael D.; Cheung, Sally W.T.; Meneghini, Marc D.

2013-01-01

194

Sequence and Expression Analyses of Ethylene Response Factors Highly Expressed in Latex Cells from Hevea brasiliensis.  

PubMed

The AP2/ERF superfamily encodes transcription factors that play a key role in plant development and responses to abiotic and biotic stress. In Hevea brasiliensis, ERF genes have been identified by RNA sequencing. This study set out to validate the number of HbERF genes, and identify ERF genes involved in the regulation of latex cell metabolism. A comprehensive Hevea transcriptome was improved using additional RNA reads from reproductive tissues. Newly assembled contigs were annotated in the Gene Ontology database and were assigned to 3 main categories. The AP2/ERF superfamily is the third most represented compared with other transcription factor families. A comparison with genomic scaffolds led to an estimation of 114 AP2/ERF genes and 1 soloist in Hevea brasiliensis. Based on a phylogenetic analysis, functions were predicted for 26 HbERF genes. A relative transcript abundance analysis was performed by real-time RT-PCR in various tissues. Transcripts of ERFs from group I and VIII were very abundant in all tissues while those of group VII were highly accumulated in latex cells. Seven of the thirty-five ERF expression marker genes were highly expressed in latex. Subcellular localization and transactivation analyses suggested that HbERF-VII candidate genes encoded functional transcription factors. PMID:24971876

Piyatrakul, Piyanuch; Yang, Meng; Putranto, Riza-Arief; Pirrello, Julien; Dessailly, Florence; Hu, Songnian; Summo, Marilyne; Theeravatanasuk, Kannikar; Leclercq, Julie; Kuswanhadi; Montoro, Pascal

2014-01-01

195

Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis  

NASA Astrophysics Data System (ADS)

Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO 3 contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO 3 concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.

Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D.; Baffa, Oswaldo

2011-11-01

196

Nocardia brasiliensis infection mimicking juvenile idiopathic arthritis in a 4-year-old girl.  

PubMed

Nocardia are ubiquitous environmental saprophytes that cause pneumonia and disseminated disease in immunocompromised patients. They can also cause localized cutaneous and soft tissue infections in healthy people after direct percutaneous inoculation. Nocardia arthritis is rare in both forms of the disease. Here we present the first published case of a child with septic arthritis caused by N brasiliensis. Importantly, this otherwise well 4-year-old girl had no known history of trauma but presented with transient cutaneous lesions and a 6-week history of arthritis involving the right fourth digit proximal interphalangeal joint without accompanying fever or raised systemic inflammatory markers. She received a diagnosis of juvenile idiopathic arthritis and underwent antiinflammatory and immunosuppressant therapy. After 2 months she developed frank septic arthritis, which necessitated a surgical joint washout, from which an intraoperative swab grew N brasiliensis. The patient received 6 months of high-dose trimethoprim-sulfamethoxazole and remains well more than 4 years after treatment. This unusual case highlights the importance of considering an indolent infection from slow-growing organisms, including Nocardia, when diagnosing the oligoarthritis subtype of juvenile idiopathic arthritis. This is especially relevant when a single joint is involved and response to antiinflammatory therapy is suboptimal because antiinflammatory agents may mask evolving signs of infection. PMID:24127474

Kapur, Nitin; Adib, Navid; Grimwood, Keith

2013-11-01

197

Pituitary gland morphogenesis and ontogeny of adenohypophyseal cells of Salminus brasiliensis (Teleostei, Characiformes).  

PubMed

In this study, we describe for the first time the details of the pituitary gland morphogenesis and the ontogeny of adenohypophyseal cells of a South American Characiform species with great importance for Brazilian Aquaculture, Salminus brasiliensis (Characiformes, Characidae), from hatching to 25 days after hatching (dah), by histochemical and immunocytochemical methods. The pituitary placode was first detected at hatching (0 dah), and the pituitary anlage became more defined at 0.5 dah. The neurohypophysis (NH) development started at 3 dah, and the early formation of its stalk at 12.5 dah. An increase in adenohypophyseal and NH tissues was also observed, and in juveniles at 25 dah, the pituitary displayed similar morphology to that found in adults of this species, displaying the main features of the teleost pituitary. PRL cells were detected at 0.5 dah, together with ACTH and ?-MSH cells, followed by GH and SL cells at 1.5 dah. ?-FSH cells were detected at 25 dah, while ?-LH cells at 5 dah. The pituitary development in this species comprises a dynamic process similar to other teleosts. Our findings in S. brasiliensis corroborate the heterogeneity in the ontogeny of adenohypophyseal cells in teleosts and suggest a role for adenohypophyseal hormones in the early development of this species. PMID:24310491

de Jesus, Lázaro Wender Oliveira; Chehade, Chayrra; Costa, Fabiano Gonçalves; Borella, Maria Inês

2014-06-01

198

Agaricus brasiliensis KA21 improves circulatory functions in spontaneously hypertensive rats.  

PubMed

The present study aimed to clarify the effects of Agaricus brasiliensis KA21 (i.e., Agaricus blazei) mushroom on circulatory function. Spontaneously hypertensive rats (SHRs) were fed 10% A. blazei-containing pellets (agaricus group) or normal pellets (control group) for 5 weeks from 6 to 11 weeks of age. For Experiment 1, tail blood pressure and heart rate were measured in the conscious SHRs. For Experiment 2, echocardiographic and blood biochemical measurements were performed in the anesthetized SHRs. In Experiment 1, blood pressure and heart rate were significantly lower in the agaricus group compared with the control group throughout the observation period. In Experiment 2, the agaricus group also showed a significant decrease in cardiac output accompanied by a decrease in heart rate and an increase in early and late ventricular filling velocity (E/A ratio). Moreover, levels of escape enzymes such as creatine kinase (CK), CK-BB, CK-MB, asparate aminotransferase, lactate dehydrogenase, and aldolase were significantly lower than in the control group. We concluded that the ingestion of feed containing A. brasiliensis KA21 can improve hypertensive cardiovascular hemodynamics by decreasing the working load of the heart, presumably by lowering the sympathetic nervous tone in SHRs. PMID:24433071

Tsubone, Hirokazu; Makimura, Yukitoshi; Hanafusa, Masakazu; Yamamoto, Yukiko; Tsuru, Yoshiharu; Motoi, Masuro; Amano, Sho

2014-03-01

199

Sequence and Expression Analyses of Ethylene Response Factors Highly Expressed in Latex Cells from Hevea brasiliensis  

PubMed Central

The AP2/ERF superfamily encodes transcription factors that play a key role in plant development and responses to abiotic and biotic stress. In Hevea brasiliensis, ERF genes have been identified by RNA sequencing. This study set out to validate the number of HbERF genes, and identify ERF genes involved in the regulation of latex cell metabolism. A comprehensive Hevea transcriptome was improved using additional RNA reads from reproductive tissues. Newly assembled contigs were annotated in the Gene Ontology database and were assigned to 3 main categories. The AP2/ERF superfamily is the third most represented compared with other transcription factor families. A comparison with genomic scaffolds led to an estimation of 114 AP2/ERF genes and 1 soloist in Hevea brasiliensis. Based on a phylogenetic analysis, functions were predicted for 26 HbERF genes. A relative transcript abundance analysis was performed by real-time RT-PCR in various tissues. Transcripts of ERFs from group I and VIII were very abundant in all tissues while those of group VII were highly accumulated in latex cells. Seven of the thirty-five ERF expression marker genes were highly expressed in latex. Subcellular localization and transactivation analyses suggested that HbERF-VII candidate genes encoded functional transcription factors.

Piyatrakul, Piyanuch; Yang, Meng; Putranto, Riza-Arief; Pirrello, Julien; Dessailly, Florence; Hu, Songnian; Summo, Marilyne; Theeravatanasuk, Kannikar; Leclercq, Julie; Kuswanhadi; Montoro, Pascal

2014-01-01

200

Complement-dependent killing of Nippostrongylus brasiliensis infective larvae by rat alveolar macrophages.  

PubMed Central

Histopathological studies have provided circumstantial evidence that helminth parasite destruction occurs in the lung; however controlled in vitro studies on the helminthocidal activity of lung cells have not been reported. This study presents evidence that Nippostrongylus brasiliensis infection in the rat induces alterations in broncho-alveolar lavage (BAL) cell numbers, differential counts, and in vitro helminthocidal activity. Normal, uninfected rats yielded 3.3 +/- 0.6 X 10(6) BAL cells/rat, consisting predominantly of alveolar macrophages (greater than 90%). However on days 2-8 post-infection there was a 1.5-2.4-fold increase in BAL cell numbers with a significant neutrophilia on day 2 and a significant increase in the absolute number of all cell types on day 8. On day 32 post-infection, BAL cell numbers had returned to control levels. Normal BAL cells neither adhered to nor killed N. brasiliensis infective larvae (L3) in the presence of rat complement. By contrast BAL cells recovered from infected rats on days, 2, 8 or 32 post-infection (D2, D8 and D32 BAL cells, respectively) adhered under similar conditions. However, only D8 and D32 BAL cells killed L3. This complement-dependent killing correlated with significantly increased numbers of C3 receptor bearing alveolar macrophages in D8 and D32 BAL cells. Complement-dependent alveolar macrophage helminthocidal activity may therefore play an important role in lung resistance against resident or migrating helminths.

Egwang, T G; Gauldie, J; Befus, D

1984-01-01

201

Chemical and agronomic development of Kalanchoe brasiliensis Camb. and Kalanchoe pinnata Pers under light and temperature levels.  

PubMed

This study compares the development of Kalanchoe brasiliensis and Kalanchoe pinnata, which are medicinal species known as "saião" and "folha da fortuna" that are used interchangeably by the population for medicinal purposes. The experiment consisted of 20 plots/species planted in plastic bags with homogeneous substrate in a randomized design, which grown under light levels (25%, 50%, 70%, full sunlight) at environment temperature, and a treatment under a plastic with greater temperature range than the external environment. It was obtained for K. pinnata a greater plant height, total length of sprouts, stems, production and dry matter content of leaves than that obtained for K. brasiliensis, which achieved higher averages only for the length of lateral branches. The species showed increases in height, which varied in inverse proportion to the light, and it was observed the influence of temperature in K. pinnata. The production and dry matter content of leaves were proportional to the luminosity; the same occurred in the thickness of leaves for K. brasiliensis. In the swelling index and Brix degree, K. brasiliensis showed higher averages than K. pinnata. In relation to the total content of flavonoids it was not observed significant differences for both species. The analyzed parameters showed the main differences in the agronomic development of the two species. PMID:22146966

Cruz, Bruna P; Chedier, Luciana M; Fabri, Rodrigo L; Pimenta, Daniel S

2011-12-01

202

Description of the female, pupa and gall of Pisphondylia brasiliensis Couri and Maia, 1992 (Diptera: Cecidomyiidae, Schizomyiina) with new records.  

PubMed

The gall of Pisphondylia brasiliensis on Guapira opposita, its female and pupa are described and illustrated. The geographic distribution of this species is now widened to Minas Gerais and Rio Grande do Sul (Brazil). For the first time, a female of the genus is described. PMID:21180914

Maia, V C; Fleury, G; Soares, G L G; Isaias, R M S

2010-11-01

203

Development and characterization of novel expressed sequence tag-derived simple sequence repeat markers in Hevea brasiliensis (rubber tree).  

PubMed

Cultivated clones of Hevea brasiliensis have a narrow genetic base. In order to broaden the genetic base, it is first necessary to investigate the genetic diversity of wild populations. Expressed sequence tag-simple sequence repeat (EST-SSR) markers were developed to investigate the genetic diversity of Hevea populations. Four hundred and thirty microsatellites were identified and 148 primers were designed to amplify the loci. Twenty-nine primer pairs were synthesized and evaluated for their ability to detect genetic polymorphisms among 40 wild accessions of H. brasiliensis. Twenty-one of the 29 loci were polymorphic. The number of alleles per locus in the 40 accessions ranged from 2 to 7. H(O) and H(E) at each locus ranged from 0.0000 to 0.9000 and from 0.0000 to 0.8704, respectively. All 21 loci could amplify in H. brasiliensis, H. pauciflora, H. nitida, H. spruceana, and H. camargoana. The EST-SSR primers developed herein can be used in genetic diversity and structure studies in H. brasiliensis. PMID:24301960

An, Z W; Li, Y C; Zhai, Q L; Xie, L L; Zhao, Y H; Huang, H S

2013-01-01

204

Polyketide synthase gene diversity within the microbiome of the sponge Arenosclera brasiliensis, endemic to the Southern Atlantic Ocean.  

PubMed

Microbes associated with marine sponges are considered important producers of bioactive, structurally unique polyketides. The synthesis of such secondary metabolites involves type I polyketide synthases (PKSs), which are enzymes that reach a maximum complexity degree in bacteria. The Haplosclerida sponge Arenosclera brasiliensis hosts a complex microbiota and is the source of arenosclerins, alkaloids with cytotoxic and antibacterial activity. In the present investigation, we performed high-throughput sequencing of the ketosynthase (KS) amplicon to investigate the diversity of PKS genes present in the metagenome of A. brasiliensis. Almost 4,000 ketosynthase reads were recovered, with about 90% annotated automatically as bacterial. A total of 235 bacterial KS contigs was rigorously assembled from this sequence pool and submitted to phylogenetic analysis. A great diversity of six type I PKS groups has been consistently detected in our phylogenetic reconstructions, including a novel and A. brasiliensis-exclusive group. Our study is the first to reveal the diversity of type I PKS genes in A. brasiliensis as well as the potential of its microbiome to serve as a source of new polyketides. PMID:23275501

Trindade-Silva, Amaro E; Rua, Cintia P J; Andrade, Bruno G N; Vicente, Ana Carolina Paulo; Silva, Genivaldo G Z; Berlinck, Roberto G S; Thompson, Fabiano L

2013-03-01

205

Effect of Agaricus brasiliensis-derived cold water extract on Toll-like receptor 2-dependent cytokine production in vitro.  

PubMed

Agaricus brasiliensis (Agaricus blazei Murrill) is well known as a medicinal mushroom. Fruit body of A. brasiliensis is rich in ?-glucan and has shown benefits for various diseases. Both hot and cold water extraction are traditional methods for intake of this mushroom extract. In the present study, we prepared cold water extract of the fruit body of A. brasiliensis (ACWS). The 1,3-?-glucan segment of this fraction was too small and did not interact with the 1,3-?-glucan receptor, dectin-1. However, ACWS could induce production of various cytokines including IL-6 from murine splenocytes. Therefore, we aimed to identify the receptor that modulates IL-6 production using ACWS. We focused our attention on Toll-like receptors (TLRs) and examined them as follows. (i) The interaction between TLRs and ACWS was screened using HEK293 cells transfected with TLR plasmid. (ii) IL-6 production from splenocytes induced by ACWS was inhibited by treatment of anti-TLR antibodies. (iii) Direct binding activity between TLR protein and ACWS was assessed by ELISA-like assay. ACWS was found to activate HEK293 cells via TLR2, 4 and 5. However, only anti-TLR2 monoclonal antibody suppressed IL-6 production from splenocytes. In addition, ACWS has the ability to bind directly to TLR2 protein. Accordingly, we suggest that fruit body of A. brasiliensis has some water-soluble TLR ligand complexes, and TLR2 on splenocytes strongly induces IL-6 production. PMID:22126586

Yamanaka, Daisuke; Motoi, Masuro; Ishibashi, Ken-ichi; Miura, Noriko N; Adachi, Yoshiyuki; Ohno, Naohito

2012-08-01

206

Signal sequence analysis of expressed sequence tags from the nematode Nippostrongylus brasiliensis and the evolution of secreted proteins in parasites  

Microsoft Academic Search

BACKGROUND: Parasitism is a highly successful mode of life and one that requires suites of gene adaptations to permit survival within a potentially hostile host. Among such adaptations is the secretion of proteins capable of modifying or manipulating the host environment. Nippostrongylus brasiliensis is a well-studied model nematode parasite of rodents, which secretes products known to modulate host immunity. RESULTS:

Yvonne M Harcus; John Parkinson; Cecilia Fernández; Jennifer Daub; Murray E Selkirk; Mark L Blaxter; Rick M Maizels

2004-01-01

207

Haematological and immunological effects of repeated dose exposure of rats to integerrimine N-oxide from Senecio brasiliensis  

Microsoft Academic Search

This study is the first in the literature to focus attention on the possible immunotoxic effect of integerrimine N-oxide content in the butanolic residue (BR) of Senecio brasiliensis, a poisonous hepatotoxic plant that contains pyrrolizidine alkaloids (PAs). PAs have been reported as a pasture and food contaminant and as herbal medicine used worldwide and are responsible for poisoning events in

Fabiana Elias; Andreia O. Latorre; Fernando Pípole; Mitsue Haraguchi; Silvana L. Górniak; Isis M. Hueza

2011-01-01

208

Polyglutamine misfolding in yeast  

PubMed Central

Protein misfolding is associated with many human diseases, including neurodegenerative diseases, such as Alzheimer disease, Parkinson disease and Huntington disease. Protein misfolding often results in the formation of intracellular or extracellular inclusions or aggregates. Even though deciphering the role of these aggregates has been the object of intense research activity, their role in protein misfolding diseases is unclear. Here, I discuss the implications of studies on polyglutamine aggregation and toxicity in yeast and other model organisms. These studies provide an excellent experimental and conceptual paradigm that contributes to understanding the differences between toxic and protective trajectories of protein misfolding. Future studies like the ones discussed here have the potential to transform basic concepts of protein misfolding in human diseases and may thus help to identify new therapeutic strategies for their treatment.

2011-01-01

209

Expanding Yeast Knowledge Online  

PubMed Central

The completion of the Saccharomyces cerevisiae genome sequencing project11 and the continued development of improved technology for large-scale genome analysis have led to tremendous growth in the amount of new yeast genetics and molecular biology data. Efficient organization, presentation, and dissemination of this information are essential if researchers are to exploit this knowledge. In addition, the development of tools that provide efficient analysis of this information and link it with pertinent information from other systems is becoming increasingly important at a time when the complete genome sequences of other organisms are becoming available. The aim of this review is to familiarize biologists with the type of data resources currently available on the World Wide Web (WWW).

DOLINSKI, KARA; BALL, CATHERINE A.; CHERVITZ, STEPHEN A.; DWIGHT, SELINA S.; HARRIS, MIDORI A.; ROBERTS, SHANNON; ROE, TAIYUN; CHERRY, J. MICHAEL; BOTSTEIN, DAVID

2011-01-01

210

Transcriptome sequencing of Hevea brasiliensis for development of microsatellite markers and construction of a genetic linkage map.  

PubMed

To obtain more information on the Hevea brasiliensis genome, we sequenced the transcriptome from the vegetative shoot apex yielding 2 311 497 reads. Clustering and assembly of the reads produced a total of 113 313 unique sequences, comprising 28 387 isotigs and 84 926 singletons. Also, 17 819 expressed sequence tag (EST)-simple sequence repeats (SSRs) were identified from the data set. To demonstrate the use of this EST resource for marker development, primers were designed for 430 of the EST-SSRs. Three hundred and twenty-three primer pairs were amplifiable in H. brasiliensis clones. Polymorphic information content values of selected 47 SSRs among 20 H. brasiliensis clones ranged from 0.13 to 0.71, with an average of 0.51. A dendrogram of genetic similarities between the 20 H. brasiliensis clones using these 47 EST-SSRs suggested two distinct groups that correlated well with clone pedigree. These novel EST-SSRs together with the published SSRs were used for the construction of an integrated parental linkage map of H. brasiliensis based on 81 lines of an F1 mapping population. The map consisted of 97 loci, consisting of 37 novel EST-SSRs and 60 published SSRs, distributed on 23 linkage groups and covered 842.9 cM with a mean interval of 11.9 cM and ?4 loci per linkage group. Although the numbers of linkage groups exceed the haploid number (18), but with several common markers between homologous linkage groups with the previous map indicated that the F1 map in this study is appropriate for further study in marker-assisted selection. PMID:22086998

Triwitayakorn, Kanokporn; Chatkulkawin, Pornsupa; Kanjanawattanawong, Supanath; Sraphet, Supajit; Yoocha, Thippawan; Sangsrakru, Duangjai; Chanprasert, Juntima; Ngamphiw, Chumpol; Jomchai, Nukoon; Therawattanasuk, Kanikar; Tangphatsornruang, Sithichoke

2011-12-01

211

Transcriptome Sequencing of Hevea brasiliensis for Development of Microsatellite Markers and Construction of a Genetic Linkage Map  

PubMed Central

To obtain more information on the Hevea brasiliensis genome, we sequenced the transcriptome from the vegetative shoot apex yielding 2 311 497 reads. Clustering and assembly of the reads produced a total of 113 313 unique sequences, comprising 28 387 isotigs and 84 926 singletons. Also, 17 819 expressed sequence tag (EST)-simple sequence repeats (SSRs) were identified from the data set. To demonstrate the use of this EST resource for marker development, primers were designed for 430 of the EST-SSRs. Three hundred and twenty-three primer pairs were amplifiable in H. brasiliensis clones. Polymorphic information content values of selected 47 SSRs among 20 H. brasiliensis clones ranged from 0.13 to 0.71, with an average of 0.51. A dendrogram of genetic similarities between the 20 H. brasiliensis clones using these 47 EST-SSRs suggested two distinct groups that correlated well with clone pedigree. These novel EST-SSRs together with the published SSRs were used for the construction of an integrated parental linkage map of H. brasiliensis based on 81 lines of an F1 mapping population. The map consisted of 97 loci, consisting of 37 novel EST-SSRs and 60 published SSRs, distributed on 23 linkage groups and covered 842.9 cM with a mean interval of 11.9 cM and ?4 loci per linkage group. Although the numbers of linkage groups exceed the haploid number (18), but with several common markers between homologous linkage groups with the previous map indicated that the F1 map in this study is appropriate for further study in marker-assisted selection.

Triwitayakorn, Kanokporn; Chatkulkawin, Pornsupa; Kanjanawattanawong, Supanath; Sraphet, Supajit; Yoocha, Thippawan; Sangsrakru, Duangjai; Chanprasert, Juntima; Ngamphiw, Chumpol; Jomchai, Nukoon; Therawattanasuk, Kanikar; Tangphatsornruang, Sithichoke

2011-01-01

212

Engineering antibodies by yeast display.  

PubMed

Since its first application to antibody engineering 15 years ago, yeast display technology has been developed into a highly potent tool for both affinity maturing lead molecules and isolating novel antibodies and antibody-like species. Robust approaches to the creation of diversity, construction of yeast libraries, and library screening or selection have been elaborated, improving the quality of engineered molecules and certainty of success in an antibody engineering campaign and positioning yeast display as one of the premier antibody engineering technologies currently in use. Here, we summarize the history of antibody engineering by yeast surface display, approaches used in its application, and a number of examples highlighting the utility of this method for antibody engineering. PMID:22450168

Boder, Eric T; Raeeszadeh-Sarmazdeh, Maryam; Price, J Vincent

2012-10-15

213

Triacylglycerol lipases of the yeast  

Microsoft Academic Search

All eukaryotes including the yeast contain a lipid storage compartment which is named lipid particle, lipid droplet or oil\\u000a body. Lipids accumulating in this subcellular fraction serve as a depot of energy and building blocks for membrane lipid synthesis.\\u000a In the yeast, the major storage lipids are triacylglycerols (TGs) and steryl esters (SEs). An important step in the life cycle

Karlheinz Grillitsch; Günther Daum

2011-01-01

214

Sociobiology of the budding yeast.  

PubMed

Social theory has provided a useful framework for research with microorganisms. Here I describe the advantages and possible risks of using a well-known model organism, the unicellular yeast Saccharomyces cerevisiae, for sociobiological research. I discuss the problems connected with clear classification of yeast behaviour based on the fitnessbased Hamilton paradigm. Relevant traits include different types of communities, production of flocculins, invertase and toxins, and the presence of apoptosis. PMID:24736156

Wloch-Salamon, Dominika M

2014-04-01

215

Cultivated strains of Agaricus bisporus and A. brasiliensis: chemical characterization and evaluation of antioxidant and antimicrobial properties for the final healthy product - natural preservatives in yoghurt.  

PubMed

Agaricus bisporus (J. E. Lange) Emil J. Imbach and Agaricus brasiliensis Wasser, M. Didukh, Amazonas & Stamets are edible mushrooms. We chemically characterized these mushrooms for nutritional value, hydrophilic and lipophilic compounds. The antioxidant and antimicrobial activities of methanolic and ethanolic extracts were assessed. Hepatotoxicity was also evaluated. The ethanolic extract of both species was tested for inhibition of Listeria monocytogenes growth in yoghurt. Both species proved to be a good source of bioactive compounds. A. brasiliensis was richer in polyunsaturated fatty acids and revealed the highest concentration of phenolic acids, and tocopherols. A. bisporus showed the highest monounsaturated fatty acids and ergosterol contents. A. brasiliensis revealed the highest antioxidant potential, and its ethanolic extract displayed the highest antibacterial potential; the methanolic extract of A. bisporus revealed the highest antifungal activity. A. brasiliensis possessed better preserving properties in yoghurt. PMID:24881564

Stojkovi?, Dejan; Reis, Filipa S; Glamo?lija, Jasmina; Ciri?, Ana; Barros, Lillian; Van Griensven, Leo J L D; Ferreira, Isabel C F R; Sokovi?, Marina

2014-07-25

216

Modeling Huntington disease in yeast  

PubMed Central

Yeast have been extensively used to model aspects of protein folding diseases, yielding novel mechanistic insights and identifying promising candidate therapeutic targets. In particular, the neurodegenerative disorder Huntington disease (HD), which is caused by the abnormal expansion of a polyglutamine tract in the huntingtin (htt) protein, has been widely studied in yeast. This work has led to the identification of several promising therapeutic targets and compounds that have been validated in mammalian cells, Drosophila and rodent models of HD. Here we discuss the development of yeast models of mutant htt toxicity and misfolding, as well as the mechanistic insights gleaned from this simple model. The role of yeast prions in the toxicity/misfolding of mutant htt is also highlighted. Furthermore, we provide an overview of the application of HD yeast models in both genetic and chemical screens, and the fruitful results obtained from these approaches. Finally, we discuss the future of yeast in neurodegenerative research, in the context of HD and other diseases.

Mason, Robert P

2011-01-01

217

IL4R?-responsive smooth muscle cells contribute to initiation of TH2 immunity and pulmonary pathology in Nippostrongylus brasiliensis infections  

Microsoft Academic Search

Nippostrongylus brasiliensis infections generate pulmonary pathologies that can be associated with strong TH2 polarization of the host's immune response. We present data demonstrating N. brasiliensis-driven airway mucus production to be dependent on smooth muscle cell interleukin 4 receptor-? (IL-4R?) responsiveness. At days 7 and 10 post infection (PI), significant airway mucus production was found in IL-4R??\\/lox control mice, whereas global

W G C Horsnell; A Vira; F Kirstein; H Mearns; J C Hoving; A J Cutler; B Dewals; E Myburgh; M Kimberg; B Arendse; N White; A Lopata; P E Burger; F Brombacher

2011-01-01

218

Royal sun medicinal mushroom Agaricus brasiliensis (higher Basidiomycetes) and the attenuation of pulmonary inflammation induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK).  

PubMed

Agaricus brasiliensis currently is one of the most studied fungi because of its nutritional and therapeutic properties as an anti-inflammatory agent and an adjuvant in cancer chemotherapy. The effects of orally administered aqueous A. brasiliensis extract (14.3- and 42.9-mg doses) on parenchymal lung damage induced by carcinogenic 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were observed in Wistar rats. NNK treatment induced pulmonary inflammation, but not lung cancer, in the rats. The lungs of animals treated with NNK showed a higher level of inflammation than those of the control group according to histopathologic examinations (P < 0.01) and kurtosis analysis (P < 0.001) of a global histogram generated from thoracic computed tomography scans. There was no significant difference in the alveolar and bronchial exudates between animals treated with a 14.3-mg dose of A. brasiliensis extract and the control without NNK. However, a significant difference was found between animals treated with NNK, received a 42.9-mg dose of A. brasiliensis (P < 0.05), and the controls not treated with NNK. We did not observe a significant difference between the kurtoses of the A. brasiliensis (14.3 mg) and control groups. However, a 42.9-mg dose of A. brasiliensis resulted in lower kurtosis values than those observed in the control group (P < 0.001). In conclusion, a low dose of A. brasiliensis was more effective in attenuating pulmonary inflammation. Similar to the histopathological results, the computed tomography scans also showed a protective effect of A. brasiliensis at the lower dose, which prevented gross pulmonary consolidation. PMID:23796216

Croccia, Carolina; Lopes, Agnaldo Jose; Pinto, Luis Felipe Ribeiro; Sabaa-Srur, Armando Ubirajara Oliveira; Vaz, Luiz Carlos Aguiar; Trotte, Marcele Nogueira de Sousa; Tessarollo, Bernardo; Silva, Aristofanes Correa; de Matos, Haroldo Jose; Nunes, Rodolfo Acatauassu

2013-01-01

219

Metabolic regulation of yeast  

NASA Astrophysics Data System (ADS)

Metabolic regulation which is based on endogeneous and exogeneous process variables which may act constantly or time dependently on the living cell is discussed. The observed phenomena of the regulation are the result of physical, chemical, and biological parameters. These parameters are identified. Ethanol is accumulated as an intermediate product and the synthesis of biomass is reduced. This regulatory effect of glucose is used for the aerobic production of ethanol. Very high production rates are thereby obtained. Understanding of the regulation mechanism of the glucose effect has improved. In addition to catabolite repression, several other mechanisms of enzyme regulation have been described, that are mostly governed by exogeneous factors. Glucose also affects the control of respiration in a third class of yeasts which are unable to make use of ethanol as a substrate for growth. This is due to the lack of any anaplerotic activity. As a consequence, diauxic growth behavior is reduced to a one-stage growth with a drastically reduced cell yield. The pulse chemostat technique, a systematic approach for medium design is developed and medium supplements that are essential for metabolic control are identified.

Fiechter, A.

1982-12-01

220

Studies on the mechanism of the self-cure reaction in rats infected with Nippostrongylus brasiliensis  

PubMed Central

The production of ovalbumin-induced anaphylaxis in rats passively immunized with antiserum to Nippostrongylus brasiliensis produced a significant reduction in their transplanted populations of adult worms compared to: (a) rats which were passively immunized alone, and (b) rats subjected to ovalbumin anaphylaxis alone. This result suggests that the physical changes associated with anaphylaxis facilitated the passage of antibody into the sub-epithelial spaces and intestinal lumen where its effect was specifically directed against the worms. Since in naturally infected rats an intestinal lesion is present, which grossly and microscopically resembles that induced by ovalbumin anaphylaxis, it was concluded that this lesion plays a similar role in the self-cure reaction. ImagesFIGS. 1-3

Barth, Ellen E. E.; Jarrett, W. F. H.; Urquhart, G. M.

1966-01-01

221

Entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana reduce the survival of Xenopsylla brasiliensis larvae (Siphonaptera: Pulicidae)  

PubMed Central

Background Entomopathogenic fungi, particularly those belonging to the genera Metarhizium and Beauveria have shown great promise as arthropod vector control tools. These agents, however, have not been evaluated against flea vectors of plague. Findings A 3-h exposure to the fungi coated paper at a concentration of 2 × 108 conidia m-2 infected >90% of flea larvae cadavers in the treatment groups. The infection reduced the survival of larvae that had been exposed to fungus relative to controls. The daily risk of dying was four- and over three-fold greater in larvae exposed to M. anisopliae (HR = 4, p<0.001) and B. bassiana (HR = 3.5, p<0.001) respectively. Both fungi can successfully infect and kill larvae of X. brasiliensis with a pooled median survival time (MST±SE) of 2±0.31 days post-exposure. Conclusion These findings justify further research to investigate the bio-control potential of entomopathogenic fungi against fleas.

2012-01-01

222

Climate and natural production of rubber ( Hevea brasiliensis) in Xishuangbanna, southern part of Yunnan province, China  

NASA Astrophysics Data System (ADS)

According to the author's and his collaborators' investigations, the climate influences the growth of rubber trees ( Hevea brasiliensis) in Xishuangbanna, the southern part of Yunnan Province, China, in at least four aspects: (1) The yield of latex per tapping and the final yield of dry rubber per tree per year or per unit area per year; (2) the growth rate, as expressed by increment of girth in cm; (3) the survival during the over-wintering period; (4) the initiation or suppression of certain diseases; In this paper the author would like to describe the influence of climatic elements on yield of latex and on survival during the over-wintering period. As for the other two aspects, only general comments are given.

Jiang, Ailiang

1988-12-01

223

Influence of soil, plant and meteorological factors on water relations and yield in Hevea brasiliensis  

NASA Astrophysics Data System (ADS)

Influence of factors governing the soil-plantatmosphere system on components of water relations and yield was studied in two clones of rubber tree, Hevea brasiliensis, viz. RRII 105 and RRII 118. Clonal variations were evident in yield and yield components and associated physiological parameters in response to soil moisture status and meteorological factors. Observations made during different seasons indicatedvariations in yield are attributed to differences in plugging index and initial flow rates, to the major yield components and also variations in components of water relations as influenced by meteorological factors. Among the two clones, RRII 105 was found to be fairly drought tolerant compared to RRII 118. RRII 105 was found to respond well to dry weather through higher stomatal resistances, higher leaf water potentials, lowered transpirational water loss and lower relative transpiration ratios, while RRII 118 was susceptible to stress situations.

Rao, G. Gururaja; Rao, P. Sanjeeva; Rajagopal, R.; Devakumar, A. S.; Vijayakumar, K. R.; Sethuraj, M. R.

1990-09-01

224

Tourism values for Mexican free-tailed bat (Tadarida brasiliensis mexicana) viewing  

USGS Publications Warehouse

Migratory species provide diverse ecosystem services to people, but these values have seldom been estimated rangewide for a single species. In this article, we summarize visitation and consumer surplus for recreational visitors to viewing sites for the Mexican free-tailed bat (Tadarida brasiliensis mexicana) throughout the Southwestern United States. Public bat viewing opportunities are available at 17 of 25 major roosts across six states; on an annual basis, we estimate that over 242,000 visitors view bats, gaining over $6.5 million in consumer surplus. A better understanding of spatial mismatches between the areas where bats provide value to people and areas most critical for maintaining migratory populations can better inform conservation planning, including economic incentive systems for conservation.

Bagstad, Kenneth J.; Widerholdt, Ruscena

2013-01-01

225

Anthocyanins from Eugenia brasiliensis edible fruits as potential therapeutics for COPD treatment  

PubMed Central

Nine anthocyanins (1–9) from the edible fruits of Eugenia brasiliensis were identified by HPLC-PDA and LC-MS, and seven of these are described for the first time in this Brazilian fruit. Two of the major anthocyanins, delphinidin (8) and cyanidin (9), were studied for their inhibitory activity against chemokine interleukin-8 (IL-8) production before and after cigarette smoke extract (CSE) treatment of cells. In non-treated cells the amount of IL-8 was unchanged following treatment with cyanidin and delphinidin in concentrations 0.1–10 M. Both delphinidin (8) and cyanidin (9) decreased the production of IL-8 in treated cells, at 1 M and 10 M, respectively. Delphinidin (8) demonstrated IL-8 inhibition in the CSE treated cells in a dose-dependent manner.

Flores, Gema; Dastmalchi, Keyvan; Paulino, Sturlainny; Whalen, Kathleen; Dabo, Abdoulaye J.; Reynertson, Kurt A.; Foronjy, Robert F.; D Armiento, Jeanine M.; Kennelly, Edward J.

2012-01-01

226

Effects of azasteroids on growth and development of the free-living stages of Nippostrongylus brasiliensis and Nematospiroides dubius.  

PubMed

25-Azasteroids were evaluated for their effects on the growth and development of the free-living stages of Nippostrongylus brasiliensis and Nematospiroides dubius. Increasing the concentration of 25-azasteroids in axenic cultures of either species resulted in a decrease in the percentage and mean length of larvae that developed to the third stage. Morphologic abnormalities of inhibited larvae were similar to those shown by larvae cultured in sterol-deficient medium. Addition of cholesterol to the culture medium reversed the inhibitive effects of azasteroid. Azasteroid completely inhibited growth and development of N. brasiliensis when the only sterol present in the culture medium was sitosterol. These results suggest similar pathways of sterol metabolism and similar mechanisms of action by azasteroids in the nematodes and insects that have been studied. PMID:6467913

Bottjer, K P; Weinstein, P P; Thompson, M J

1984-01-01

227

Candida zeylanoides: another opportunistic yeast.  

PubMed Central

A patient with a long history of scleroderma and gastrointestinal malabsorption requiring total parenteral nutrition was admitted with Candida zeylanoides fungemia. The yeast responded to therapy, but on two subsequent admissions for episodes of fever the blood cultures yielded the same yeast. The identity of the Candida species was established biochemically by both the API (Analytab) and Vitek system approaches. C. zeylanoides ATCC 20356 and ATCC 7351 served as controls for these analyses and for antifungal susceptibility studies and restriction endonuclease analyses of chromosomal DNA. These investigations indicated that representative isolates of the yeasts from the three episodes were identical and differed in several respects from the ATCC strains, which did not share many of the characteristics bands with the DNA restriction fragment analysis. C. zeylanoides variants capable of tolerating 35 degrees C can complicate the recovery of patients, especially individuals compromised by their underlying disease. Images

Levenson, D; Pfaller, M A; Smith, M A; Hollis, R; Gerarden, T; Tucci, C B; Isenberg, H D

1991-01-01

228

Cdc42 Oscillations in Yeasts  

NSDL National Science Digital Library

A fundamental problem in cell biology is how cells define one or several discrete sites of polarity. Through mechanisms involving positive and negative feedback, the small Rho-family guanosine triphosphatase Cdc42 breaks symmetry in round budding yeast cells to define a single site of polarized cell growth. However, it is not clear how cells can define multiple sites of polarization concurrently. We discuss a study in which rod-shaped fission yeast cells, which naturally polarize growth at their two cell ends, exhibited oscillations of Cdc42 activity between these sites. We compare these findings with similar oscillatory behavior of Cdc42 detected in budding yeast cells and discuss the possible mechanism and functional outputs of these oscillations.

Felipe O. Bendezu (Switzerland;University of Lausanne REV); Sophie G. Martin (Switzerland;University of Lausanne REV)

2012-12-04

229

De novo transcriptome analysis of Hevea brasiliensis tissues by RNA-seq and screening for molecular markers  

PubMed Central

Background The rubber tree, Hevea brasiliensis, is a species native to the Brazilian Amazon region and it supplies almost all the world’s natural rubber, a strategic raw material for a variety of products. One of the major challenges for developing rubber tree plantations is adapting the plant to biotic and abiotic stress. Transcriptome analysis is one of the main approaches for identifying the complete set of active genes in a cell or tissue for a specific developmental stage or physiological condition. Results Here, we report on the sequencing, assembling, annotation and screening for molecular markers from a pool of H. brasiliensis tissues. A total of 17,166 contigs were successfully annotated. Then, 2,191 Single Nucleotide Variation (SNV) and 1.397 Simple Sequence Repeat (SSR) loci were discriminated from the sequences. From 306 putative, mainly non-synonymous SNVs located in CDS sequences, 191 were checked for their ability to characterize 23 Hevea genotypes by an allele-specific amplification technology. For 172 (90%), the nucleotide variation at the predicted genomic location was confirmed, thus validating the different steps from sequencing to the in silico detection of the SNVs. Conclusions This is the first study of the H. brasiliensis transcriptome, covering a wide range of tissues and organs, leading to the production of the first developed SNP markers. This process could be amplified to a larger set of in silico detected SNVs in expressed genes in order to increase the marker density in available and future genetic maps. The results obtained in this study will contribute to the H. brasiliensis genetic breeding program focused on improving of disease resistance and latex yield.

2014-01-01

230

Distributional potential of the Triatoma brasiliensis species complex at present and under scenarios of future climate conditions  

PubMed Central

Background The Triatoma brasiliensis complex is a monophyletic group, comprising three species, one of which includes two subspecific taxa, distributed across 12 Brazilian states, in the caatinga and cerrado biomes. Members of the complex are diverse in terms of epidemiological importance, morphology, biology, ecology, and genetics. Triatoma b. brasiliensis is the most disease-relevant member of the complex in terms of epidemiology, extensive distribution, broad feeding preferences, broad ecological distribution, and high rates of infection with Trypanosoma cruzi; consequently, it is considered the principal vector of Chagas disease in northeastern Brazil. Methods We used ecological niche models to estimate potential distributions of all members of the complex, and evaluated the potential for suitable adjacent areas to be colonized; we also present first evaluations of potential for climate change-mediated distributional shifts. Models were developed using the GARP and Maxent algorithms. Results Models for three members of the complex (T. b. brasiliensis, N?=?332; T. b. macromelasoma, N?=?35; and T. juazeirensis, N?=?78) had significant distributional predictivity; however, models for T. sherlocki and T. melanica, both with very small sample sizes (N?=?7), did not yield predictions that performed better than random. Model projections onto future-climate scenarios indicated little broad-scale potential for change in the potential distribution of the complex through 2050. Conclusions This study suggests that T. b. brasiliensis is the member of the complex with the greatest distributional potential to colonize new areas: overall; however, the distribution of the complex appears relatively stable. These analyses offer key information to guide proactive monitoring and remediation activities to reduce risk of Chagas disease transmission.

2014-01-01

231

Identification of a Hevea brasiliensis Latex Manganese Superoxide Dismutase (Hev b 10) as a Cross-Reactive Allergen  

Microsoft Academic Search

Background: Cross-reactive allergens play an increasingly important role in latex allergy in complicating both the diagnosis and time course of allergic symptoms. Manganese superoxide dismutase (MnSOD), a ubiquitous protein of prokaryotic and eukaryotic organisms, was described as a cross-reactive allergen in Aspergillus fumigatus. Little information is available on the importance of this pan-allergen in Hevea brasiliensis latex. The aim of

Stefan Wagner; Slawomir Sowka; Christina Mayer; Reto Crameri; Margit Focke; Viswanath P. Kurup; Otto Scheiner; Heimo Breiteneder

2001-01-01

232

Effects of Zn supplementation on the growth, amino acid composition, polysaccharide yields and anti-tumour activity of Agaricus brasiliensis  

Microsoft Academic Search

The effects of Zn supplementation on the growth, amino acid composition, polysaccharide yields and anti-tumour activity of Agaricus brasiliensis were studied. An initial Zn concentration within the range of 0–300 mg\\/l had a significant effect on the cell growth and Zn biosorption. At an initial Zn concentration of 300 mg\\/l, a maximal extracellular polysaccharide (EPS) yield of 5.08 ± 0.25 g\\/l was

Xiang Zou

2005-01-01

233

Photosynthetic capacity and temperature responses of photosynthesis of rubber trees ( Hevea brasiliensis Müll. Arg.) acclimate to changes in ambient temperatures  

Microsoft Academic Search

The aim of this study was to assess the temperature response of photosynthesis in rubber trees (Hevea brasiliensis Müll. Arg.) to provide data for process-based growth modeling, and to test whether photosynthetic capacity and temperature\\u000a response of photosynthesis acclimates to changes in ambient temperature. Net CO2 assimilation rate (A) was measured in rubber saplings grown in a nursery or in

Boonthida Kositsup; Pierre Montpied; Poonpipope Kasemsap; Philippe Thaler; Thierry Améglio; Erwin Dreyer

2009-01-01

234

Wound-Induced Accumulation of mRNA Containing a Hevein Sequence in Laticifers of Rubber Tree (Hevea brasiliensis)  

Microsoft Academic Search

Hevein is a chitin-binding protein that is present in laticifers of the rubber tree (Hevea brasiliensis). A cDNA clone (HEV1) encoding hevein was isolated by using the polymerase chain reaction with mixed oligonucleotides corresponding to two regions of hevein as primers and a Hevea latex cDNA library as a template. HEV1 is 1018 base pairs long and includes an open

Willem Broekaert; Hyung-Il Lee; Anil Kush; Nam-Hai Chua; Natasha Raikhel

1990-01-01

235

Preventive activity of pyrrolizidine alkaloids from Senecio brasiliensis (Asteraceae) on gastric and duodenal induced ulcer on mice and rats  

Microsoft Academic Search

The alkaloid extract of Senecio brasiliensis inflorescences contain a mixture of the pyrrolizidine alkaloids (PA) senecionine, integerrimine, retrorsine, usaramine and seneciphylline. We evaluated this PA mixture on preventive antiulcerogenic effects on standard rodent models of induced gastric and duodenal ulcers. In the HCl\\/ethanol, indomethacin–bethanechol and hypothermic-restraint-induced gastric ulcer, the lesion was significantly inhibited by PA (p.o.) (p < 0.001). In

Walber Toma; José Roberto Trigo; Ana Cláudia Bensuaski de Paula; Alba Regina Monteiro Souza Brito

2004-01-01

236

Transient Responses of Yeasts to Glucose Excess.  

National Technical Information Service (NTIS)

The thesis describes the physiological responses of yeasts when they are transferred from glucose limitation to glucose excess. In certain organisms such as Saccharomyces cerevisiae, bakers' yeast, this change in environmental conditions results in an imm...

H. van Urk

1989-01-01

237

Disruption of Yeast Membranes by Methylphenidate.  

National Technical Information Service (NTIS)

Methylphenidate blocked sorbose uptake and loss by yeast spheroplasts and, at higher concentrations, disrupted spheroplasts. At high concentrations methylphenidate also ruptured the membranes of whole yeast cells; sorbose and 280 nm-absorbing materials we...

E. Spoerl

1970-01-01

238

Pentose utilization in yeasts: Physiology and biochemistry.  

National Technical Information Service (NTIS)

The fermentive performance of bacteria, yeasts, and filamentous fungi was investigated in a pentose (xylose)-rich lignocellulosic hydrolyzate. The filamentous fungus Fusarium oxysporum and the xylose-fermenting yeast Pichia stipitis were found to be very ...

H. Jeppson

1996-01-01

239

Yeast Can Affect Behavior and Learning.  

ERIC Educational Resources Information Center

A pediatrician recounts his experiences in diagnosing and treating allergies to common yeast germs that may result in behavior and learning problems. He lists characteristics that may predispose children to yeast-connected health problems. (CL)

Crook, William G.

1984-01-01

240

The Yeast Nuclear Pore Complex  

PubMed Central

An understanding of how the nuclear pore complex (NPC) mediates nucleocytoplasmic exchange requires a comprehensive inventory of the molecular components of the NPC and a knowledge of how each component contributes to the overall structure of this large molecular translocation machine. Therefore, we have taken a comprehensive approach to classify all components of the yeast NPC (nucleoporins). This involved identifying all the proteins present in a highly enriched NPC fraction, determining which of these proteins were nucleoporins, and localizing each nucleoporin within the NPC. Using these data, we present a map of the molecular architecture of the yeast NPC and provide evidence for a Brownian affinity gating mechanism for nucleocytoplasmic transport.

Rout, Michael P.; Aitchison, John D.; Suprapto, Adisetyantari; Hjertaas, Kelly; Zhao, Yingming; Chait, Brian T.

2000-01-01

241

Selection and improvement of wine yeasts  

Microsoft Academic Search

The selection of wine yeasts is usually carried out within the species Saccha- romyces cerevisiae. It aims at identifying the yeast strains that, besides fermenting grape juice vigorously and producing high ethanol yield, can also positively influence the com- position and the sensorial characteristics of wine. The natural availability of yeast strains possessing an ideal combination of oenological characteristics is

S. RAINIERI; I. S. PRETORIUS

242

Continuous ethanol production using induced yeast aggregates  

Microsoft Academic Search

The induction of yeast cell aggregates in a column reactor was initiated by packing yeast cell paste of Saccharomyces uvarum into the column, and then YMP broth was fed into the column from the bottom at a linear flow rate of 2.5 cm\\/h. Thereafter, yeast cells aggregated in the column within 48 h without a supply of oxygen. When this

LiFu Chen; Cheng-Shung Gong

1986-01-01

243

Yeast: A Research Organism for Teaching Genetics.  

ERIC Educational Resources Information Center

Explains why laboratory strains of bakers yeast, Saccharomyces cerevisiae, are particularly suited for classroom science activities. Describes the sexual life cycle of yeast and the genetic system with visible mutations. Presents an overview of activities that can be done with yeast and gives a source for teachers to obtain more information. (PR)

Manney, Thomas R.; Manney, Monta L.

1992-01-01

244

Enological functions of parietal yeast mannoproteins  

Microsoft Academic Search

Parietal yeast mannoproteins play a very important role in the overall vinification process. Their production and release, both during winemaking and aging on lees, depends on the specific yeast strain and the nutritional conditions. The following enological functions of parietal yeast mannoproteins have been described: (a) adsorption of ochratoxin A; (b) combination with phenolic compounds; (c) increased growth of malolactic

Andrea Caridi

2006-01-01

245

Phylogenetics of Saccharomycetales, the ascomycete yeasts  

Microsoft Academic Search

Ascomycete yeasts (phylum Ascomycota: subphylum Saccharomycotina: class Saccharomycetes: order Saccharomycetales) comprise a monophyletic lineage with a single order of about 1000 known species. These yeasts live as saprobes, often in association with plants, animals and their interfaces. A few species account for most human mycotic infections, and fewer than 10 species are plant pathogens. Yeasts are responsible for important industrial

Sung-Oui Suh; Meredith Blackwell; Cletus P. Kurtzman; M.-A. Lachance

2006-01-01

246

Beer brewing using a fusant between a sake yeast and a brewer's yeast  

Microsoft Academic Search

Beer brewing using a fusant between a sake yeast (a lysine auxotrophic mutant of sake yeast K-14) and a brewer's yeast (a respiratory-deficient mutant of the top fermentation yeast NCYC1333) was performed to take advantage of the beneficial characteristics of sake yeasts, i.e., the high productivity of esters, high tolerance to ethanol, and high osmotolerance. The fusant (F-32) obtained was

Nobuhiko Mukai; Chiharu Nishimori; Ikuko Wilson Fujishige; Akihiro Mizuno; Toshiro Takahashi; Kazuo Sato

2001-01-01

247

TDP-43 toxicity in yeast.  

PubMed

The budding yeast Saccharomyces cerevisiae is an emerging tool for investigating the molecular pathways that underpin several human neurodegenerative disorders associated with protein misfolding. Amyotrophic lateral sclerosis (ALS) is a devastating adult onset neurodegenerative disease primarily affecting motor neurons. The protein TDP-43 has recently been demonstrated to play an important role in the disease, however, the mechanisms by which TDP-43 contributes to pathogenesis are unclear. To explore the mechanistic details that result in aberrant accumulation of TDP-43 and to discover potential strategies for therapeutic intervention, we employed a yeast TDP-43 proteinopathy model system. These studies allowed us to determine the regions of TDP-43 required for aggregation and toxicity and to define the effects of ALS-linked mutant forms of TDP-43. We have also been able to harness the power of yeast genetics to identify potent modifiers of TDP-43 toxicity using high-throughput yeast genetic screens. Here, we describe the methods and approaches that we have used in order to gain insight into TDP-43 biology and its role in disease. These approaches are readily adaptable to other neurodegenerative disease proteins. PMID:21115123

Armakola, Maria; Hart, Michael P; Gitler, Aaron D

2011-03-01

248

Yeast Proteomics and Protein Microarrays  

PubMed Central

Our understanding of biological processes as well as human diseases has improved greatly thanks to studies on model organisms such as yeast. The power of scientific approaches with yeast lies in its relatively simple genome, its facile classical and molecular genetics, as well as the evolutionary conservation of many basic biological mechanisms. However, even in this simple model organism, systems biology studies, especially proteomic studies had been an intimidating task. During the past decade, powerful high-throughput technologies in proteomic research have been developed for yeast including protein microarray technology. The protein microarray technology allows the interrogation of protein-protein, protein-DNA, protein-small molecule interaction networks as well as post-translational modification networks in a large-scale, high-throughput manner. With this technology, many groundbreaking findings have been established in studies with the budding yeast Saccharomyces cerevisiae, most of which could have been unachievable with traditional approaches. Discovery of these networks has profound impact on explicating biological processes with a proteomic point of view, which may lead to a better understanding of normal biological phenomena as well as various human diseases.

Chen, Rui; Snyder, Michael

2010-01-01

249

Maximising the yeast chronological lifespan.  

PubMed

When investigating aging it is important to focus on the factors that are needed to attain, and which can be manipulated to extend, the longest lifespans. This has long been appreciated by those workers who use Drosophila or Caenorhabditis elegans as model experimental systems to study aging. Often though it seems it is not a consideration in many studies of yeast chronological aging. In this chapter I summarise how recent work has revealed the preconditioning that is needed for yeast to survive for long periods in stationary phase, therefore for it to exhibit a long chronological life span (CLS). Of critical importance in this regard is the nature of the nutrient limitation that, during the earlier growth phase, had forced the cells to undergo growth arrest. I have attempted to highlight those studies that have focussed on the longest CLSs, as this helps to identify investigations that may be addressing - not just factors that can influence chronological longevity - but those factors that are correlated with the authentic processes of chronological aging. Attempting to maximize long-term stationary survival in yeast should also enhance the potential relevance of this organism as an aging model to those who wrestle with the problems of aging in more complex systems. Finally I also give a personal perspective of how studies on the yeast CLS may still yet provide some important new insights into events that are correlated with aging. PMID:22094421

Piper, Peter W

2012-01-01

250

Toxicogenomics using yeast DNA microarrays  

Microsoft Academic Search

Development of genomics and bioinformatics enable us to analyze the global gene expression profiles of cells by DNA microarray. Changes in gene expression patterns indicate changes in its physiological conditions. Following the exposure of an organism or cell to toxic chemicals or other environmental stresses, the global genetic responses can be expeditiously and easily analyzed. Baker's yeast, Saccharomyces cerevisiae, is

Daisuke Yasokawa; Hitoshi Iwahashi

2010-01-01

251

Dielectric properties of yeast cells  

Microsoft Academic Search

Summary Dielectric measurements were made on suspensions of intact yeast cells over a frequency range of 10 kHz to 100 MHz. The suspensions showed typical dielectric dispersions, which are considered to be caused by the presence of cytoplasmic membranes with sufficiently low conductivity. Since the conductivity of the cell wall was found to be of nearly the same value as

Koji Asami; Tetsuya Hanai; Naokazu Koizumi

1976-01-01

252

Emerging technologies in yeast genomics  

Microsoft Academic Search

The genomic revolution is undeniable: in the past year alone, the term 'genomics' was found in nearly 500 research articles, and at least 6 journals are devoted solely to genomic biology. More than just a buzzword, molecular biology has genuinely embraced genomics (the systematic, large-scale study of genomes and their functions). With its facile genetics, the budding yeast Saccharomyces cerevisiae

Anuj Kumar; Michael Snyder

2001-01-01

253

Yeasts in an industrial malting ecosystem.  

PubMed

The malting ecosystem consists of two components: the germinating cereal grains and the complex microbial community. Yeasts and yeast-like fungi are an important part of this ecosystem, but the composition and the effects of this microbial group have been largely unknown. In this study we surveyed the development of yeasts and yeast-like fungi in four industrial scale malting processes. A total of 136 malting process samples were collected and examined for the presence of yeasts growing at 15, 25 and 37 degrees C. More than 700 colonies were isolated and characterized. The isolates were discriminated by PCR-fingerprinting with microsatellite primer (M13). Yeasts representing different fingerprint types were identified by sequence analysis of the D1/D2 domain of the 26S rRNA gene. Furthermore, identified yeasts were screened for the production of alpha-amylase, beta-glucanase, cellulase and xylanase. A numerous and diverse yeast community consisting of both ascomycetous (25) and basidiomycetous (18) species was detected in the various stages of the malting process. The most frequently isolated ascomycetous yeasts belonged to the genera Candida, Clavispora, Galactomyces, Hanseniaspora, Issatchenkia, Pichia, Saccharomyces and Williopsis and the basidiomycetous yeasts to Bulleromyces, Filobasidium, Cryptococcus, Rhodotorula, Sporobolomyces and Trichosporon. In addition, two ascomycetous yeast-like fungi (black yeasts) belonging to the genera Aureobasidium and Exophiala were commonly detected. Yeasts and yeast-like fungi produced extracellular hydrolytic enzymes with a potentially positive contribution to the malt enzyme spectrum. Knowledge of the microbial diversity provides a basis for microflora management and understanding of the role of microbes in the cereal germination process. PMID:16758169

Laitila, A; Wilhelmson, A; Kotaviita, E; Olkku, J; Home, S; Juvonen, R

2006-11-01

254

Activation of the Na sup + ,K sup + -ATPase in Narcine brasiliensis  

SciTech Connect

The in vivo activation and turnover rates of the sodium pump (Na{sup +},K{sup +}-ATPase) were investigated in the electrocytes of the electric organ of the elasmobranch Narcine brasiliensis. The Narcine electric organ appears to be an excellent model for the study of sodium pump activation in an excitable tissue. The sodium transmembrane gradient and high-energy phosphagens were concurrently measured by {sup 23}Na and {sup 31}P NMR spectroscopy. The resting electric organ, which depends primarily on anaerobic metabolism displays a high concentration of phosphocreatin (PCr). It has an intracellular sodium concentration ((Na{sup +}){sub i}) of 20{plus minus}10 milliequivalents/liter as estimated by NMR. Electrical stimulation of the nerves innervating the electric organ results in an increase in (Na{sup +}){sub i} in the electrolyte and rapid depletion of PCr. Ouabain causes an 85% decrease in utilization of high-energy phosphagens, indicating that rapid PCr turnover in this tissue is mainly due to Na{sup +},K{sup +}-ATPase activity. From these data the authors can determine that the rate of sodium pump turnover increases by >3 orders of magnitude within several hundred milliseconds. The authors conclude that cholinergic stimulation of the electric organ causes a rapid and extremely large increase in sodium pump turnover, which is regulated predominantly by factors other than (Na{sup +}){sub i}.

Blum, H.; Nioka, Shoko; Johnson, R.G. Jr. (Univ. of Pennsylvania School of Medicine, Philadelphia (USA))

1990-02-01

255

Effects of DDE on experimentally poisoned free-tailed bats (Tadarida brasiliensis): Lethal brain concentrations  

USGS Publications Warehouse

Adult female free-tailed bats (Tadarida brasiliensis) were collected at Bracken Cave, Texas, and shipped to the Patuxent Wildlife Research Center. Treated mealworms (Tenebrio molitor) containing 107 ppm DDE were fed to 17 bats; five other bats were fed untreated mealworms. After 40 days on dosage, during which one dosed bat was killed accidentally, four dosed bats were frozen and the remaining 17 were starved to death. The objective was to elevate brain levels of DDE to lethality and measure these concentrations. After the feeding period, dosed bats weighed less than controls. After starvation, the body condition of dosed bats was poorer than that of controls even though there was no difference in the amounts of carcass fat. During starvation, dosed bats lost weight faster than controls. Also, four dosed bats exhibited the prolonged tremoring that characterizes DDE poisoning. DDE increased in brains of starving bats as fat was metabolized. The estimated mean brain concentration of DDE diagnostic of death was 519 ppm with a range of 458-564 ppm. These values resemble diagnostic levels known for two species of passerine birds, but they exceed published levels for two free-tailed bats from Carlsbad Caverns, New Mexico.

Clark, D.R., Jr.; Kroll, J.C.

1977-01-01

256

Divergent DNA methylation patterns associated with abiotic stress in Hevea brasiliensis.  

PubMed

Cytosine methylation is a fundamental epigenetic mechanism for gene-expression regulation and development in plants. Here, we report for the first time the identification of DNA methylation patterns and their putative relationship with abiotic stress in the tree crop Hevea brasiliensis (source of 99% of natural rubber in the world). Regulatory sequences of four major genes involved in the mevalonate pathway (rubber biosynthesis pathway) and one general defense-related gene of three high-yielding popular rubber clones grown at two different agroclimatic conditions were analyzed for the presence of methylation. We found several significant variations in the methylation pattern at core DNA binding motifs within all the five genes. Several consistent clone-specific and location-specific methylation patterns were identified. The differences in methylation pattern observed at certain pivotal cis-regulatory sites indicate the direct impact of stress on the genome and support the hypothesis of site-specific stress-induced DNA methylation. It is assumed that some of the methylation patterns observed may be involved in the stress-responsive mechanism in plants by which they adapt to extreme conditions. The study also provide clues towards the existence of highly divergent phenotypic characters among Hevea clones despite their very similar genetic make-up. Altogether, the observations from this study prove beyond doubt that there exist epigenetic variations in Hevea and environmental factors play a significant role in the induction of site-specific epigenetic mutations in its genome. PMID:21705581

Uthup, Thomas K; Ravindran, Minimol; Bini, K; Thakurdas, Saha

2011-11-01

257

Antioxidative polyphenols from Nigerian mistletoe Loranthus micranthus (Linn.) parasitizing on Hevea brasiliensis.  

PubMed

Two new phenolic glycosides, linamarin gallate (1) and walsuraside B (2), together with nine known compounds, catechin (3), epicatechin (4), epicatechin 3-O-gallate (5), epicatechin 3-O-(3-O-methyl)gallate (6), epicatechin 3-O-(3,5-O-dimethyl)gallate (7), epicatechin 3-O-(3,4,5-O-trimethyl)gallate (8), quercetin 3-O-?-d-glucopyranoside (9), rutin (10), and peltatoside (11), were isolated from the leafy twigs of Nigerian mistletoe Loranthus micranthus (Linn.) parasitic on Hevea brasiliensis. Compound 1 was characterized as an unusual cyanogenic glycoside, while compound 8 was isolated for the first time from a natural source. This is the first report of a cyanogenic glycoside from mistletoes. The structures of the new compounds were unambiguously elucidated by 1D ((1)H, (13)C), 2D NMR (COSY, HSQC, and HMBC) and by mass spectroscopy. The antioxidant activities of the isolated compounds (1-11) were evaluated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. PMID:23422225

Agbo, Matthias Onyebuchi; Lai, Daowan; Okoye, Festus B C; Osadebe, Patience O; Proksch, Peter

2013-04-01

258

The small RNA profile in latex from Hevea brasiliensis trees is affected by tapping panel dryness.  

PubMed

Natural rubber is harvested by tapping Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg. Harvesting stress can lead to tapping panel dryness (TPD). MicroRNAs (miRNAs) are induced by abiotic stress and regulate gene expression by targeting the cleavage or translational inhibition of target messenger RNAs. This study set out to sequence miRNAs expressed in latex cells and to identify TPD-related putative targets. Deep sequencing of small RNAs was carried out on latex from trees affected by TPD using Solexa technology. The most abundant small RNA class size was 21 nucleotides for TPD trees compared with 24 nucleotides in healthy trees. By combining the LeARN pipeline, data from the Plant MicroRNA database and Hevea EST sequences, we identified 19 additional conserved and four putative species-specific miRNA families not found in previous studies on rubber. The relative transcript abundance of the Hbpre-MIR159b gene increased with TPD. This study revealed a small RNA-specific signature of TPD-affected trees. Both RNA degradation and a shift in miRNA biogenesis are suggested to explain the general decline in small RNAs and, particularly, in miRNAs. PMID:24218245

Gébelin, Virginie; Leclercq, Julie; Kuswanhadi; Argout, Xavier; Chaidamsari, Tetty; Hu, Songnian; Tang, Chaorong; Sarah, Gautier; Yang, Meng; Montoro, Pascal

2013-10-01

259

Rubber elongation factor (REF), a major allergen component in Hevea brasiliensis latex has amyloid properties.  

PubMed

REF (Hevb1) and SRPP (Hevb3) are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of ?-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom. PMID:23133547

Berthelot, Karine; Lecomte, Sophie; Estevez, Yannick; Coulary-Salin, Bénédicte; Bentaleb, Ahmed; Cullin, Christophe; Deffieux, Alain; Peruch, Frédéric

2012-01-01

260

Hevea brasiliensis cell suspension peroxidase: purification, characterization and application for dye decolorization.  

PubMed

Peroxidases are oxidoreductase enzymes produced by most organisms. In this study, a peroxidase was purified from Hevea brasiliensis cell suspension by using anion exchange chromatography (DEAE-Sepharose), affinity chromatography (Con A-agarose) and preparative SDS-PAGE. The obtained enzyme appeared as a single band on SDS-PAGE with molecular mass of 70 kDa. Surprisingly, this purified peroxidase also had polyphenol oxidase activity. However, the biochemical characteristics were only studied in term of peroxidase because similar experiments in term of polyphenol oxidase have been reported in our pervious publication. The optimal pH of the purified peroxidase was 5.0 and its activity was retained at pH values between 5.0-10.0. The enzyme was heat stable over a wide range of temperatures (0-60°C), and less than 50% of its activity was lost at 70°C after incubation for 30 min. The enzyme was completely inhibited by ?-mercaptoethanol and strongly inhibited by NaN3; in addition, its properties indicated that it was a heme containing glycoprotein. This peroxidase could decolorize many dyes; aniline blue, bromocresol purple, brilliant green, crystal violet, fuchsin, malachite green, methyl green, methyl violet and water blue. The stability against high temperature and extreme pH supported that the enzyme could be a potential peroxidase source for special industrial applications. PMID:23402438

Chanwun, Thitikorn; Muhamad, Nisaporn; Chirapongsatonkul, Nion; Churngchow, Nunta

2013-01-01

261

Cloning and molecular characterization of a cDNA encoding a small GTPase from Hevea brasiliensis.  

PubMed

Small GTPases play a critical role in the regulation of a range of cellular processes including growth, differentiation, and intracellular transportation. The cDNA encoding a small GTPase, designated as HbGTPase1, was isolated from Hevea brasiliensis. HbGTPase1 was 882 bp long containing a 612-bp open reading frame encoding a putative protein of 203 amino acids, flanked by an 83-bp 5'-untranslated region (UTR) and a 187-bp 3'-UTR. The predicted molecular mass of HbGTPase1 is 22.62 kDa, with an isoelectric point of 5.06. The HbGTPase1 protein was predicted to possess the conserved functional regions of the small GTPase superfamily of proteins. Quantitative polymerase chain reaction analysis revealed that HbGTPase1 was constitutively expressed in all tissues tested. HbGTPase1 transcripts accumulated at relatively low levels in the flower, latex, and leaves, while HbGTPase1 transcripts accumulated at relatively high levels in bark. Transcription of HbGTPase1 in the latex was induced by jasmonate. PMID:24065672

Li, H L; Guo, D; Tian, W M; Peng, S Q

2013-01-01

262

Diversity of the cassiicolin gene in Corynespora cassiicola and relation with the pathogenicity in Hevea brasiliensis.  

PubMed

Corynespora cassiicola is an important plant pathogenic Ascomycete causing the damaging Corynespora Leaf Fall (CLF) disease in rubber tree (Hevea brasiliensis). A small secreted glycoprotein named cassiicolin was previously described as an important effector of C. cassiicola. In this study, the diversity of the cassiicolin-encoding gene was analysed in C. cassiicola isolates sampled from various hosts and geographical origins. A cassiicolin gene was detected in 47 % of the isolates, encoding up to six distinct protein isoforms. In three isolates, two gene variants encoding cassiicolin isoforms Cas2 and Cas6 were found in the same isolate. A phylogenetic tree based on four combined loci and elucidating the diversity of the whole collection was strongly structured by the toxin class, as defined by the cassiicolin isoform. The isolates carrying the Cas1 gene (toxin class Cas1), all grouped in the same highly supported clade, were found the most aggressive on two rubber tree cultivars. Some isolates in which no Cas gene was detected could nevertheless generate moderate symptoms, suggesting the existence of other yet uncharacterized effectors. This study provides a useful base for future studies of C. cassiicola population biology and epidemiological surveys in various host plants. PMID:24433675

Déon, Marine; Fumanal, Boris; Gimenez, Stéphanie; Bieysse, Daniel; Oliveira, Ricardo R; Shuib, Siti Shuhada; Breton, Frédéric; Elumalai, Sunderasan; Vida, João B; Seguin, Marc; Leroy, Thierry; Roeckel-Drevet, Patricia; Pujade-Renaud, Valérie

2014-01-01

263

Identification and characterization of the 14-3-3 gene family in Hevea brasiliensis.  

PubMed

The 14-3-3 proteins are a family of conserved phospho-specific binding proteins involved in diverse physiological processes. Although the genome-wide analysis of this family has been carried out in certain plant species, little is known about 14-3-3 protein genes in rubber tree (Hevea brasiliensis). In this study, we identified 10 14-3-3 protein genes (designated as HbGF14a to HbGF14j) in the latest rubber tree genome. A phylogenetic tree was constructed and found to demonstrate that HbGF14s can be divided into two major groups. Tissue-specific expression profiles showed that 10 HbGF14 were expressed in at least one of the tissues, which suggested that HbGF14s participated in numerous cellular processes. The 10 HbGF14s responded to jasmonic acid (JA) and ethylene (ET) treatment, which suggested that these HbGF14s were involved in response to JA and ET signaling. The target of HbGF14c protein was related to small rubber particle protein, a major rubber particle protein that is involved in rubber biosynthesis. These findings suggested that 14-3-3 proteins may be involved in the regulation of natural rubber biosynthesis. PMID:24751399

Yang, Zi-Ping; Li, Hui-Liang; Guo, Dong; Tang, Xiao; Peng, Shi-Qing

2014-07-01

264

Characterization of a cassiicolin-encoding gene from Corynespora cassiicola, pathogen of rubber tree (Hevea brasiliensis).  

PubMed

Corynespora Leaf Fall (CLF) is a major disease of rubber tree (Hevea brasiliensis) caused by the Ascomycota Corynespora cassiicola. Here we describe the cloning and characterization of a gene encoding cassiicolin (Cas), a glycosylated cystein-rich small secreted protein (SSP) identified as a potential CLF disease effector in rubber tree. Three isolates with contrasted levels of aggressiveness were analyzed comparatively. The cassiicolin gene was detected - and the toxin successfully purified - from the isolates with high and medium aggressiveness (CCP and CCAM3 respectively) but not from the isolate with the lowest aggressiveness (CCAM1), suggesting the existence of a different disease effector in the later. CCP and CCAM3 carried strictly identical cassiicolin genes and produced toxins of identical mass, as evidence by mass spectrometry analysis, thus suggesting conserved post-translational modifications in addition to sequence identity. The differences in aggressiveness between CCP and CCAM3 may be attributed to differences in cassiicolin transcript levels rather than qualitative variations in cassiicolin structure. Cassiicolin may play an important role in the early phase of infection since a peak of cassiicolin transcripts occurred in 1 or 2 days after inoculation (before the occurrence of the first symptoms), in both the tolerant and the susceptible cultivars. PMID:22325885

Déon, Marine; Bourré, Yanice; Gimenez, Stéphanie; Berger, Angélique; Bieysse, Daniel; de Lamotte, Frédéric; Poncet, Joël; Roussel, Véronique; Bonnot, François; Oliver, Gérald; Franchel, Jérôme; Seguin, Marc; Leroy, Thierry; Roeckel-Drevet, Patricia; Pujade-Renaud, Valérie

2012-04-01

265

Relationship between latex yield of Hevea brasiliensis and antecedent environmental parameters  

NASA Astrophysics Data System (ADS)

A study on the relationship between latex yield and antecedent environmental data was undertaken for five clones (RRII203, RRII118, RRIM600, RRII105 and GT1) of Hevea brasiliensis (rubber) in Agartala, northeast India, a region in which rubber is not traditionally cultivated. The explained variance for the regression equations based on parameters determined on the day of tapping and up to 3 days prior to it, varied from 72% to 37% during the NWT period and 94 83% during the WT period. Soil moisture storage, 1 and 3 days prior to tapping, was found to be the primary parameter affecting yield for the NWT and WT periods, respectively. It was observed that the clone RRII105, with a comparatively lower yield to that of RRIM600, was more susceptible to daily WD conditions during the non-winter season. RRIM600 and RRII105 being high-yielding clones were also found to be fairly dependent on the AT of the day prior to tapping. The mean lag period correlation of this parameter with yield was also found to be higher during the WT period than during the NWT period. As a whole, the mean lag period based on prior measurements of environmental variables showed optimum correlation with yield at 15 20 days prior to the day of tapping. The study also confirms that varied responses of yield with environmental factors in this non-traditional region of rubber cultivation depend on clonal character.

Raj, Shammi; Das, Gitali; Pothen, Jacob; Dey, Sushil Kumar

2005-01-01

266

Defense-related polyphenol oxidase from Hevea brasiliensis cell suspension: purification and characterization.  

PubMed

Polyphenol oxidase (PPO) was examined from the extract of leaf, seed, and cell suspension of Hevea brasiliensis, a rubber plant. The defense-related isozyme from Hevea cell suspension induced by culture filtrate of Phytophthora palmivora or by agitation stress was isolated through anion exchange and affinity chromatography, respectively. A 104-purification fold, migrated as a single band of 70 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis of PPO, was obtained after further purified by the preparative gel electrophoresis. Based on reaction with catechol and dopamine but not with p-cresol and guaiacol, it is a diphenol-type PPO. The values of V(max)/K(m) ratio indicated that catechol was the most specific substrate. The optimal activity of the purified PPO was observed at pH 6.0. The PPO activity was retained at pH 4.0-10.0 and temperature 10-60 °C. The inhibitors which completely inhibited the activity were ascorbic acid, dithiothreitol, and ?-mercaptoethanol while sodium azide was a poor inhibitor. The PPO obtained from Hevea cell suspension possesses high specific activity and is stable at wide range of pH and temperature. It is therefore suitable for extreme condition uses and may lead to an alternative source of PPO in various industrial applications. PMID:22532343

Muhamad, Nisaporn; Chirapongsatonkul, Nion; Churngchow, Nunta

2012-05-01

267

Rubber (Hevea brasiliensis) seed oil toxicity effect and Linamarin compound analysis  

PubMed Central

Background The lipid fraction of rubber (Hevea brasiliensis (kunth. Muell)) seed was extracted and analyzed for toxicological effect. The toxicological compound such as linamarin in rubber seed oil (RSO) extracted using different solvents, such as hexane (RSOh), mixture of chloroform?+?methanol (RSOchl+mth) and ethanol (RSOeth) were also studied. Various methods analysis such as Fourier transforms infrared spectroscopy (FTIR) and colorimetric methods were carried out to determine the present of such compounds. Results FTIR spectrum of RSO did not show any presence of cyanide peak. The determination of cyanide by using colorimetric method was demonstrated no response of the cyanide in RSO and didn’t show any colored comparing with commercial cyanide which observed blue color. The results showed that no functional groups such as cyanide (C???N) associated with linamarin were observed. Toxicological test using rats was also conducted to further confirm the absence of such compounds. RSO did not show any toxic potential to the rats. Bioassay experiments using shrimps had been used as test organisms to evaluate the toxicity of linamarin extract from RSOh, RSOchl+mth and RSOeth and LC50 were found to be (211.70?%, 139.40?%, and 117.41?%, respectively). Conclusions This can be attributed no hazardous linamarin were found in RSO.

2012-01-01

268

Hevea brasiliensis cell suspension peroxidase: purification, characterization and application for dye decolorization  

PubMed Central

Peroxidases are oxidoreductase enzymes produced by most organisms. In this study, a peroxidase was purified from Hevea brasiliensis cell suspension by using anion exchange chromatography (DEAE-Sepharose), affinity chromatography (Con A-agarose) and preparative SDS-PAGE. The obtained enzyme appeared as a single band on SDS-PAGE with molecular mass of 70 kDa. Surprisingly, this purified peroxidase also had polyphenol oxidase activity. However, the biochemical characteristics were only studied in term of peroxidase because similar experiments in term of polyphenol oxidase have been reported in our pervious publication. The optimal pH of the purified peroxidase was 5.0 and its activity was retained at pH values between 5.0–10.0. The enzyme was heat stable over a wide range of temperatures (0–60°C), and less than 50% of its activity was lost at 70°C after incubation for 30 min. The enzyme was completely inhibited by ?-mercaptoethanol and strongly inhibited by NaN3; in addition, its properties indicated that it was a heme containing glycoprotein. This peroxidase could decolorize many dyes; aniline blue, bromocresol purple, brilliant green, crystal violet, fuchsin, malachite green, methyl green, methyl violet and water blue. The stability against high temperature and extreme pH supported that the enzyme could be a potential peroxidase source for special industrial applications.

2013-01-01

269

Antiproliferative effects of lectins from Canavalia ensiformis and Canavalia brasiliensis in human leukemia cell lines.  

PubMed

The antiproliferative activity of lectins Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr) were studied using human leukemia MOLT-4 and HL-60 cell lines. It was revealed that both ConA and ConBr were markedly cytotoxic to cells using MTT and NAC assays. The IC(50) values were approximately 3 and 20 ?g/mL for ConA and ConBr, respectively, for both MOLT-4 and HL-60 cells. However, in normal human peripheral blood lymphocytes, the lectins were not cytotoxic, even when tested at concentrations as high as 200 ?g/ml. Using comet assay, the lectins produced a rate of DNA damage exceeding 80% in MOLT-4 and HL-60 cells. Fluorescence analysis revealed the morphology characteristic of apoptosis, with low concentrations of apoptotic bodies and fragmented DNA (5 ?g/ml). Flow cytometric analysis demonstrated an accumulation of cells in the sub-G1 cell cycle that is characteristic of DNA fragmentation, and a decrease in membrane integrity at high concentrations. Lastly, we evaluated the alterations in mitochondrial potential that reduced after treatment with lectins. Our results indicate that ConA and ConBr inhibited cell proliferation selectively in tumor cells and that apoptosis was the main death mechanism. Therefore, lectins can be considered a class of molecules with a high antitumor activity potential. PMID:22776218

Faheina-Martins, Glaucia V; da Silveira, Alethéia Lacerda; Cavalcanti, Bruno C; Ramos, Márcio V; Moraes, Manoel O; Pessoa, Cláudia; Araújo, Demetrius A M

2012-10-01

270

Recombinagenic activity of integerrimine, a pyrrolizidine alkaloid from Senecio brasiliensis, in somatic cells of Drosophila melanogaster.  

PubMed

Integerrimine (ITR), a pyrrolizidine alkaloid from Senecio brasiliensis, was tested for genotoxicity using the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster. The compound was administered by chronic feeding (48 hours) of 3-day-old larvae. Two different crosses involving the markers flare (flr) and multiple wing hairs (mwh) were used, that is, the standard (ST) cross and the high bioactivation (HB) cross, which has a high cytochrome P450-dependent bioactivation capacity. In both crosses, the wings of two types of progeny were analyzed, that is, inversion-free marker heterozygotes and balancer heterozygotes carrying multiple inversions. ITR was found to be equally potent in inducing spots in a dose-related manner in the marker heterozygotes of both crosses. This indicates that the bioactivation capacity present in larvae of the ST cross is sufficient to reveal the genotoxic activity of ITR. In the balancer heterozygotes of both crosses, where all recombinational events are eliminated due to the inversions, the frequencies of induced spots were considerably reduced which documents the recombinagenic activity of ITR. Linear regression analysis of the dose response relationships for both genotypes shows that 85% to 90% of the wing spots are due to mitotic recombination. PMID:9020312

Campesato, V R; Graf, U; Reguly, M L; de Andrade, H H

1997-01-01

271

The formation of 5-phosphomevalonate by mevalonate kinase in Hevea brasiliensis latex  

PubMed Central

1. Evidence has been produced for the formation of 5-phosphomevalonate from potassium dl-mevalonate by the latex of Hevea brasiliensis and by reconstituted freeze-dried serum obtained from this latex. 2. The enzyme, mevalonate kinase, catalysing the formation of 5-phosphomevalonate from potassium dl-mevalonate and ATP has been partially purified. 3. 5-Phosphomevalonate formed by the purified mevalonate kinase from potassium [2-14C]mevalonate has been shown to be incorporated by latex into rubber to about 2·4 times the extent of dl-mevalonate. 4. The enzyme can utilize inosine triphosphate as effectively as adenosine triphosphate as a phosphate donor and is also slightly active with uridine triphosphate. 5. The enzyme was fairly stable to a range of pH values and temperatures, the activity being optimum at pH7·5 and 60–70°. The energy of activation was 10·7kcal./mole. The Km values were 0·13mm for potassium dl-mevalonate and 2·0mm for ATP at 30°. 6. The enzyme required the presence of Mn2+ (1mm) for maximum activity; this could be replaced by Mg2+ (4mm), which was less effective, and by Ca2+, which was far less effective. 6. Although the enzyme did not require cysteine or reduced glutathione for activation in aerobic conditions, it was inhibited by reagents known to react with thiol groups.

Williamson, I. P.; Kekwick, R. G. O.

1965-01-01

272

A novel and enantioselective epoxide hydrolase from Aspergillus brasiliensis CCT 1435: purification and characterization.  

PubMed

A novel epoxide hydrolase from Aspergillus brasiliensis CCT1435 (AbEH) was cloned and overexpressed in Escherichia coli cells with a 6xHis-tag and purified by nickel affinity chromatography. Gel filtration analysis and circular dichroism measurements indicated that this novel AbEH is a homodimer in aqueous solution and contains the typical secondary structure of an ?/? hydrolase fold. The activity of AbEH was initially assessed using the fluorogenic probe O-(3,4-epoxybutyl) umbelliferone and was active in a broad range of pH (6-9) and temperature (25-45°C); showing optimum performance at pH 6.0 and 30°C. The Michaelis constant (KM) and maximum rate (Vmax) values were 495?M and 0.24?M/s, respectively. Racemic styrene oxide (SO) was used as a substrate to assess the AbEH activity and enantioselectivity, and 66% of the SO was hydrolyzed after only 5min of reaction, with the remaining (S)-SO ee exceeding 99% in a typical kinetic resolution behavior. The AbEH-catalyzed hydrolysis of SO was also evaluated in a biphasic system of water:isooctane; (R)-diol in 84% ee and unreacted (S)-SO in 36% ee were produced, with 43% conversion in 24h, indicating a discrete enantioconvergent behavior for AbEH. This novel epoxide hydrolase has biotechnological potential for the preparation of enantiopure epoxides or vicinal diols. PMID:23973866

Beloti, Lilian L; Costa, Bruna Z; Toledo, Marcelo A S; Santos, Clelton A; Crucello, Aline; Fávaro, Marianna T P; Santiago, André S; Mendes, Juliano S; Marsaioli, Anita J; Souza, Anete P

2013-10-01

273

The degradation rates of cytoplasmic tRNA, rRNA and mRNA in rats are elevated after infection with Nippostrongylus brasiliensis.  

PubMed

The effects of a parasitic infection with the nematode Nippostrongylus brasiliensis on the degradation rates of cytoplasmic tRNA, rRNA and mRNA in rats have been investigated by measuring the renal excretion rates of the modified RNA catabolites N6-threoninocarbonyladenosine, pseudouridine and 7-methylguanine. Between days 9 and 13 post-infection when the expulsion of N. brasiliensis is usually the most pronounced, the degradation rates of the different RNA classes were significantly higher than in the control rats (P < 0.05) by, on average, +24% (tRNA), +34% (rRNA) and +26% (mRNA). We suspect that the elevated degradation rates of RNA are related to an increased production of reactive oxygen species by the host during the expulsion of N. brasiliensis. PMID:9509030

Topp, H; Duden, R; Stephan, U; Schöch, G

1998-02-01

274

When yeast cells meet, karyogamy!  

PubMed Central

Cytoskeleton-mediated transport processes are central to the subcellular organization of cells. The nucleus constitutes the largest organelle of a cell, and studying how it is positioned and moved around during various types of cell morphogenetic processes has puzzled researchers for a long time. Now, the molecular architectures of the underlying dynamic processes start to reveal their secrets.   In yeast, karyogamy denotes the migration of two nuclei toward each other—termed nuclear congression—upon partner cell mating and the subsequent fusion of these nuclei to form a diploid nucleus. It constitutes a well-studied case. Recent insights completed the picture about the molecular processes involved and provided us with a comprehensive model amenable to quantitative computational simulation of the process. This review discusses our understanding of yeast nuclear congression and karyogamy and seeks to explain how a detailed, quantitative and systemic understanding has emerged from this knowledge.

Gibeaux, Romain; Knop, Michael

2013-01-01

275

Preparation of extracts from yeast.  

PubMed

Because yeast is exceptionally well suited to genetic analysis, both classical and molecular, it is an attractive system for expressing recombinant animal proteins for purification purposes. Methods available for lysing yeast cells include autolysis, pressure cells (e.g., French press), abrasives (glass bead vortexing), and enzymatic lysis (e.g., zymolase). One of the simplest methods, discussed in this protocol, involves the abrasive action of well-agitated glass beads. This is a very effective method for both low volumes (e.g., <1 mL using a microcentrifuge tube) and many liters using a specialized DynoMill apparatus. Cell breakage is typically >95%, as assessed by phase-contrast microscopy. PMID:21205845

Simpson, Richard J

2011-01-01

276

Okazaki Fragment Maturation in Yeast  

Microsoft Academic Search

In the presence of proliferating cell nuclear antigen, yeast DNA polymerase (Pol ) replicated DNA at a rate of 40 - 60 nt\\/s. When downstream double-stranded DNA was encountered, Pol paused, but most replication complexes proceeded to carry out strand-displacement synthesis at a rate of 1.5 nt\\/s. In the presence of the flap endonuclease FEN1 (Rad27), the complex carried out

Rao Ayyagari; Xavier V. Gomes; Dmitry A. Gordenin; Peter M. J. Burgers

2003-01-01

277

Zero background yeast reporter plasmids.  

PubMed

UAS-less reporter plasmids are widespread and powerful tools for the identification and analysis of binding sites for transcriptional activators. The common reporter plasmids for the yeast Saccharomyces cerevisiae are multicopy (2mu) vectors with the CYC1 core promoter upstream of the lacZ gene. Insertion of putative or known activator binding sites upstream of the core promoter puts lacZ (beta-galactosidase) expression under the control of the corresponding activator. Although these constructs have proved to work well for most purposes, they have certain limitations: (1) they give significant and carbon-source-dependent lacZ background expression; (2) unlike most other yeast promoters, the CYC1 upstream region has a partially open chromatin structure with an accessible TATA box; (3) they use only a single, moderately sensitive reporter; and (4) the use of multicopy vectors can result in activator titration. Here, we introduce novel reporter plasmids based on the yeast MEL1 (alpha-galactosidase) gene that can overcome all of these limitations. It is also shown that background expression is due to fortuitous activator binding sites within the plasmid backbones that are insufficiently shielded from the core promoters in the common CYC1 reporter plasmids. PMID:10773444

Melcher, K; Sharma, B; Ding, W V; Nolden, M

2000-04-18

278

Pheromone Signaling Pathways in Yeast  

NSDL National Science Digital Library

The actions of many extracellular stimuli are elicited by complexes of cell surface receptors, heterotrimeric guanine nucleotide–binding proteins (G proteins), and mitogen-activated protein kinase (MAPK) complexes. Analysis of haploid yeast cells and their response to peptide mating pheromones has produced important advances in the understanding of G protein and MAPK signaling mechanisms. Many of the components, their interrelationships, and their regulators were first identified in yeast. Examples include definitive demonstration of a positive signaling role for G protein βγ subunits, the discovery of a three-tiered structure of the MAPK module, development of the concept of a kinase-scaffold protein, and the discovery of the first regulator of G protein signaling protein. New and powerful genomic, proteomic, and computational approaches available in yeast are beginning to uncover new pathway components and interactions and have revealed their presence in unexpected locations within the cell. This updated Connections Map in the Database of Cell Signaling includes several major revisions to this prototypical signal response pathway.

Henrik G. Dohlman (University of North Carolina;Department of Biochemistry and Biophysics REV); Janna E. Slessareva (University of North Carolina;Department of Biochemistry and Biophysics REV)

2006-12-05

279

Spatial analysis of egg distribution and geographic changes in the spawning habitat of the Brazilian sardine Sardinella brasiliensis.  

PubMed

This paper establishes the spawning habitat of the Brazilian sardine Sardinella brasiliensis and investigates the spatial variability of egg density and its relation with oceanographic conditions in the shelf of the south-east Brazil Bight (SBB). The spawning habitats of S. brasiliensis have been defined in terms of spatial models of egg density, temperature-salinity plots, quotient (Q) analysis and remote sensing data. Quotient curves (Q(C)) were constructed using the geographic distribution of egg density, temperature and salinity from samples collected during nine survey cruises between 1976 and 1993. The interannual sea surface temperature (SST) variability was determined using principal component analysis on the SST anomalies (SSTA) estimated from remote sensing data over the period between 1985 and 2007. The spatial pattern of egg occurrences in the SBB indicated that the largest concentration occurred between Paranaguá and São Sebastião. Spawning habitat expanded and contracted during the years, fluctuating around Paranaguá. In January 1978 and January 1993, eggs were found nearly everywhere along the inner shelf of the SBB, while in January 1988 and 1991 spawning had contracted to their southernmost position. The SSTA maps for the spawning periods showed that in the case of habitat expansion (1993 only) anomalies over the SBB were zero or slightly negative, whereas for the contraction period anomalies were all positive. Sardinella brasiliensis is capable of exploring suitable spawning sites provided by the entrainment of the colder and less-saline South Atlantic Central Water onto the shelf by means of both coastal wind-driven (to the north-east of the SBB) and meander-induced (to the south-west of the SBB) upwelling. PMID:21155781

Gigliotti, E S; Gherardi, D F M; Paes, E T; Souza, R B; Katsuragawa, M

2010-12-01

280

De Novo Assembly and Transcriptome Analysis of the Rubber Tree (Hevea brasiliensis) and SNP Markers Development for Rubber Biosynthesis Pathways.  

PubMed

Hevea brasiliensis (Willd. Ex Adr. Juss.) Muell.-Arg. is the primary source of natural rubber that is native to the Amazon rainforest. The singular properties of natural rubber make it superior to and competitive with synthetic rubber for use in several applications. Here, we performed RNA sequencing (RNA-seq) of H. brasiliensis bark on the Illumina GAIIx platform, which generated 179,326,804 raw reads on the Illumina GAIIx platform. A total of 50,384 contigs that were over 400 bp in size were obtained and subjected to further analyses. A similarity search against the non-redundant (nr) protein database returned 32,018 (63%) positive BLASTx hits. The transcriptome analysis was annotated using the clusters of orthologous groups (COG), gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Pfam databases. A search for putative molecular marker was performed to identify simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs). In total, 17,927 SSRs and 404,114 SNPs were detected. Finally, we selected sequences that were identified as belonging to the mevalonate (MVA) and 2-C-methyl-D-erythritol 4-phosphate (MEP) pathways, which are involved in rubber biosynthesis, to validate the SNP markers. A total of 78 SNPs were validated in 36 genotypes of H. brasiliensis. This new dataset represents a powerful information source for rubber tree bark genes and will be an important tool for the development of microsatellites and SNP markers for use in future genetic analyses such as genetic linkage mapping, quantitative trait loci identification, investigations of linkage disequilibrium and marker-assisted selection. PMID:25048025

Mantello, Camila Campos; Cardoso-Silva, Claudio Benicio; da Silva, Carla Cristina; de Souza, Livia Moura; Scaloppi Junior, Erivaldo José; de Souza Gonçalves, Paulo; Vicentini, Renato; de Souza, Anete Pereira

2014-01-01

281

De Novo Assembly and Transcriptome Analysis of the Rubber Tree (Hevea brasiliensis) and SNP Markers Development for Rubber Biosynthesis Pathways  

PubMed Central

Hevea brasiliensis (Willd. Ex Adr. Juss.) Muell.-Arg. is the primary source of natural rubber that is native to the Amazon rainforest. The singular properties of natural rubber make it superior to and competitive with synthetic rubber for use in several applications. Here, we performed RNA sequencing (RNA-seq) of H. brasiliensis bark on the Illumina GAIIx platform, which generated 179,326,804 raw reads on the Illumina GAIIx platform. A total of 50,384 contigs that were over 400 bp in size were obtained and subjected to further analyses. A similarity search against the non-redundant (nr) protein database returned 32,018 (63%) positive BLASTx hits. The transcriptome analysis was annotated using the clusters of orthologous groups (COG), gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Pfam databases. A search for putative molecular marker was performed to identify simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs). In total, 17,927 SSRs and 404,114 SNPs were detected. Finally, we selected sequences that were identified as belonging to the mevalonate (MVA) and 2-C-methyl-D-erythritol 4-phosphate (MEP) pathways, which are involved in rubber biosynthesis, to validate the SNP markers. A total of 78 SNPs were validated in 36 genotypes of H. brasiliensis. This new dataset represents a powerful information source for rubber tree bark genes and will be an important tool for the development of microsatellites and SNP markers for use in future genetic analyses such as genetic linkage mapping, quantitative trait loci identification, investigations of linkage disequilibrium and marker-assisted selection.

Mantello, Camila Campos; Cardoso-Silva, Claudio Benicio; da Silva, Carla Cristina; de Souza, Livia Moura; Scaloppi Junior, Erivaldo Jose; de Souza Goncalves, Paulo; Vicentini, Renato; de Souza, Anete Pereira

2014-01-01

282

Histochemical study of the hepatopancreas in adult females of the pink-shrimp Farfantepenaeus brasiliensis Latreille, 1817.  

PubMed

This study provides histochemical data of the hepatopancreatic cells of adult female pink-shrimp (Farfantepenaeus brasiliensis) at two different developmental stages (those with developed gonads and those with exhausted gonads). The F. brasiliensis females were collected in seawater off the Guarapari coast, Espirito Santo, Brazil. Five cell types were identified in this digestive gland: B (vesicular), E (embryonic), F (fibrillar), M (basal) and R (resorptive). The digestive gland was stained with the following techniques: PAS/Alcian blue (for polysaccharides), bromophenol blue (for protein), von Kossa (for bound calcium) and Baker (for lipids). Acid glycoconjugates were found inside vacuoles in the R cells, while neutral polysaccharides were present in the B cells and near to the microvilli. In females with exhausted gonads polysaccharides were also seen in the intertubular spaces and inside the lumina of the tubules. The F and M cells were the most marked by the presence of large amounts of proteins observed in R cells and also inside the vacuoles of B cells. The bound calcium was mainly found in the F and M cells. The F cells showed strong positive staining for lipid while the R cell only stained weakly. The E cells did not react to any of the applied staining techniques. The similarities in the histochemical composition of these hepatopancreatic cells in females with developed gonads, compared to exhausted ones, is justified by the fact that transfer of these elements to the oocytes occurs, in significant quantity, only during the initial stages of gonadal development in F. brasiliensis. Also, they may be more related to the molt stage, as in the case of calcium salts. PMID:23992941

Nunes, Erika Takagi; Braga, Adriane Araújo; Camargo-Mathias, Maria Izabel

2014-01-01

283

Physiological properties of some yeast strains.  

PubMed

Twenty yeast strains have recently been isolated in pure cultures from natural and industrial sources and identified based mainly on physiological properties. The majority of the strains (15) are alcohologenic belonging to the genus Saccharomyces and comprise two brewer's (beer) yeast strains (S. carlsbergensis= S. uvarum A and B), two baker's yeast strains (S. cerevisiae CA and CP), one spirit yeast strain (S. cerevisiae CF) and ten wine yeast strains (S. cerevisiae var. ellipsoideus = S. ellipsoideus 1, 3, 4, 6, 8 and 9; S. oviformis 2, 5 and 7; and S. uvarum 10). The other 5 yeast strains belong to different species: Kloeckera apiculate, Candida mycoderma (Mycoderma vini), Pichia membranaefaciens, Rhodotorula glutinis and Torulopsis holmii, respectively. PMID:16841476

Oprean, Letitia; Gaspar, Enikö; Lengyel, Ecaterina; Cristea, V

2006-06-01

284

Yeasts Diversity in Fermented Foods and Beverages  

NASA Astrophysics Data System (ADS)

People across the world have learnt to culture and use the essential microorganisms for production of fermented foods and alcoholic beverages. A fermented food is produced either spontaneously or by adding mixed/pure starter culture(s). Yeasts are among the essential functional microorganisms encountered in many fermented foods, and are commercially used in production of baker's yeast, breads, wine, beer, cheese, etc. In Asia, moulds are predominant followed by amylolytic and alcohol-producing yeasts in the fermentation processes, whereas in Africa, Europe, Australia and America, fermented products are prepared exclusively using bacteria or bacteria-yeasts mixed cultures. This chapter would focus on the varieties of fermented foods and alcoholic beverages produced by yeasts, their microbiology and role in food fermentation, widely used commercial starters (pilot production, molecular aspects), production technology of some common commercial fermented foods and alcoholic beverages, toxicity and food safety using yeasts cultures and socio-economy

Tamang, Jyoti Prakash; Fleet, Graham H.

285

Metabolic engineering of malolactic wine yeast.  

PubMed

Malolactic fermentation is essential for the deacidification of high acid grape must. We have constructed a genetically stable industrial strain of Saccharomyces cerevisiae by integrating a linear cassette containing the Schizosaccharomyces pombe malate permease gene (mae1) and the Oenococcus oeni malolactic gene (mleA) under control of the S. cerevisiae PGK1 promoter and terminator sequences into the URA3 locus of an industrial wine yeast. The malolactic yeast strain, ML01, fully decarboxylated 5.5 g/l of malate in Chardonnay grape must during the alcoholic fermentation. Analysis of the phenotype, genotype, transcriptome, and proteome revealed that the ML01 yeast is substantially equivalent to the parental industrial wine yeast. The ML01 yeast enjoys 'Generally Regarded As Safe' status from the FDA and is the first genetically enhanced yeast that has been commercialized. Its application will prevent the formation of noxious biogenic amines produced by lactic acid bacteria in wine. PMID:16621641

Husnik, John I; Volschenk, Heinrich; Bauer, Jurgen; Colavizza, Didier; Luo, Zongli; van Vuuren, Hennie J J

2006-07-01

286

Method for Fingerprinting Yeast Cell Wall Mannans  

PubMed Central

Controlled acetolysis of yeast mannans yields mixtures of oligosaccharides with (1?2) and (1?3) linkages between the mannose units, whereas the less stable (1?6) linkages of the polysaccharide backbone are cleaved. The “fingerprints,” obtained by gel filtration of the oligosaccharide mixtures, can be used to distinguish between the different yeast mannans. The general method may be useful for determining the taxonomy of yeasts and for making correlations between immunochemical reactivity and mannan structure.

Kocourek, Jan; Ballou, Clinton E.

1969-01-01

287

Production of ethanol by immobilized yeast cells  

Microsoft Academic Search

Saccharomyces cerevisiae cells were immobilized in calcium alginate beads for use in the continuous production of ethanol. Yeasts were grown in medium supplemented with ethanol to selectively screen for a culture which showed the greatest tolerance to ethanol inhibition. Yeast beads were produced from a yeast slurry containing 1.5% alginate (w\\/v) which was added as drops to a 0.05M CaCl2

David Williams; Douglas M. Munnecke

1981-01-01

288

The yeast Golgi apparatus: insights and mysteries  

PubMed Central

The Golgi apparatus is known to modify and sort newly synthesized secretory proteins. However, fundamental mysteries remain about the structure, operation, and dynamics of this organelle. Important insights have emerged from studying the Golgi in yeasts. For example, yeasts have provided direct evidence for Golgi cisternal maturation, a mechanism that is likely to be broadly conserved. Here, we highlight features of the yeast Golgi as well as challenges that lie ahead.

Papanikou, Effrosyni; Glick, Benjamin S.

2009-01-01

289

Assembly of eukaryotic algal chromosomes in yeast  

PubMed Central

Background Synthetic genomic approaches offer unique opportunities to use powerful yeast and Escherichia coli genetic systems to assemble and modify chromosome-sized molecules before returning the modified DNA to the target host. For example, the entire 1 Mb Mycoplasma mycoides chromosome can be stably maintained and manipulated in yeast before being transplanted back into recipient cells. We have previously demonstrated that cloning in yeast of large (>?~?150 kb), high G?+?C (55%) prokaryotic DNA fragments was improved by addition of yeast replication origins every ~100 kb. Conversely, low G?+?C DNA is stable (up to at least 1.8 Mb) without adding supplemental yeast origins. It has not been previously tested whether addition of yeast replication origins similarly improves the yeast-based cloning of large (>150 kb) eukaryotic DNA with moderate G?+?C content. The model diatom Phaeodactylum tricornutum has an average G?+?C content of 48% and a 27.4 Mb genome sequence that has been assembled into chromosome-sized scaffolds making it an ideal test case for assembly and maintenance of eukaryotic chromosomes in yeast. Results We present a modified chromosome assembly technique in which eukaryotic chromosomes as large as ~500 kb can be assembled from cloned ~100 kb fragments. We used this technique to clone fragments spanning P. tricornutum chromosomes 25 and 26 and to assemble these fragments into single, chromosome-sized molecules. We found that addition of yeast replication origins improved the cloning, assembly, and maintenance of the large chromosomes in yeast. Furthermore, purification of the fragments to be assembled by electroelution greatly increased assembly efficiency. Conclusions Entire eukaryotic chromosomes can be successfully cloned, maintained, and manipulated in yeast. These results highlight the improvement in assembly and maintenance afforded by including yeast replication origins in eukaryotic DNA with moderate G?+?C content (48%). They also highlight the increased efficiency of assembly that can be achieved by purifying fragments before assembly.

2013-01-01

290

6-azauracil sensitivity assay for yeast.  

PubMed

INTRODUCTIONTreatment of yeast with 6-Azauracil (6AU) leads to a reduction of intracellular GTP levels. The reduction in GTP levels is not itself lethal, but can block yeast growth when combined with mutations that affect transcriptional elongation. 6AU sensitivity thus can be used as a crude assay to test for mutations that affect transcriptional elongation. The assay described here requires growing saturated cultures of yeast, counting, and spotting serial dilutions of yeast on both CSM and CSM + 6AU plates. PMID:22484669

Tansey, William P

2006-01-01

291

Simplified techniques for identifying foodborne yeasts.  

PubMed

Four problematic areas associated with the identification of foodborne yeasts are discussed. These consist of (1) the inability of conventional identification tests to recognize some common and important foodborne yeasts characterized by genomic differences (e.g., Saccharomyces cerevisiae, S. bayanus and S. pastorianus); (2) the delay in application of non-traditional identification methods such as DNA fingerprinting, chromosome karyotyping, protein electrophoretic patterns and fatty acid profiles for routine identification purposes; (3) the lack of commercially available manual or automated identification systems dedicated to the diagnosis of foodborne yeasts; and (4) the disregard for considering ecological frequency of yeasts in computerized probabilistic identification systems. PMID:8357753

Deák, T

1993-06-25

292

Role of glucose signaling in yeast metabolism  

SciTech Connect

The conversion of glucose to ethanol and carbon dioxide by yeast was the first biochemical pathway to be studied in detail. The initial observation that this process is catalyzed by an extract of yeast led to the discovery of enzymes and coenzymes and laid the foundation for modern biochemistry. In this article, knowledge concerning the relation between uptake of and signaling by glucose in the yeast Saccharomyces cerevisiae is reviewed and compared to the analogous process in prokaryotes. It is concluded that (much) more fundamental knowledge concerning these processes is required before rational redesign of metabolic fluxes from glucose in yeast can be achieved.

Dam, K. van [Univ. of Amsterdam (Netherlands). E.C. Slater Inst.

1996-10-05

293

Evaluation of Automated Yeast Identification System  

NASA Technical Reports Server (NTRS)

One hundred and nine teleomorphic and anamorphic yeast isolates representing approximately 30 taxa were used to evaluate the accuracy of the Biolog yeast identification system. Isolates derived from nomenclatural types, environmental, and clinica isolates of known identity were tested in the Biolog system. Of the isolates tested, 81 were in the Biolog database. The system correctly identified 40, incorrectly identified 29, and was unable to identify 12. Of the 28 isolates not in the database, 18 were given names, whereas 10 were not. The Biolog yeast identification system is inadequate for the identification of yeasts originating from the environment during space program activities.

McGinnis, M. R.

1996-01-01

294

Three-dimensional structures of enzyme-substrate complexes of the hydroxynitrile lyase from Hevea brasiliensis.  

PubMed Central

The 3D structures of complexes between the hydroxynitrile lyase from Hevea brasiliensis (Hb-HNL) and several substrate and/or inhibitor molecules, including trichloracetaldehyde, hexafluoracetone, acetone, and rhodanide, were determined by X-ray crystallography. The complex with trichloracetaldehyde showed a covalent linkage between the protein and the inhibitor, which had apparently resulted from nucleophilic attack of the catalytic Ser80-Ogamma. All other complexes showed the substrate or inhibitor molecule merely hydrogen bonded to the protein. In addition, the native crystal structure of Hb-HNL was redetermined at cryo-temperature and at room temperature, eliminating previous uncertainties concerning residual electron density within the active site, and leading to the observation of two conserved water molecules. One of them was found to be conserved in all complex structures and appears to have mainly structural significance. The other water molecule is conserved in all structures except for the complex with rhodanide; it is hydrogen bonded to the imidazole of the catalytic His235 and appears to affect the Hb-HNL catalyzed reaction. The observed 3D structural data suggest implications for the enzyme mechanism. It appears that the enzyme-catalyzed cyanohydrin formation is unlikely to proceed via a hemiacetal or hemiketal intermediate covalently attached to the enzyme, despite the observation of such an intermediate for the complex with trichloracetaldehyde. Instead, the data are consistent with a mechanism where the incoming substrate is activated by hydrogen bonding with its carbonyl oxygen to the Ser80 and Thr11 hydroxy groups. A hydrogen cyanide molecule subsequently replaces a water molecule and is deprotonated presumably by the His235 base. Deprotonation is facilitated by the proximity of the positive charge of the Lys236 side chain.

Zuegg, J.; Gruber, K.; Gugganig, M.; Wagner, U. G.; Kratky, C.

1999-01-01

295

Identification of novel microRNAs in Hevea brasiliensis and computational prediction of their targets  

PubMed Central

Background Plants respond to external stimuli through fine regulation of gene expression partially ensured by small RNAs. Of these, microRNAs (miRNAs) play a crucial role. They negatively regulate gene expression by targeting the cleavage or translational inhibition of target messenger RNAs (mRNAs). In Hevea brasiliensis, environmental and harvesting stresses are known to affect natural rubber production. This study set out to identify abiotic stress-related miRNAs in Hevea using next-generation sequencing and bioinformatic analysis. Results Deep sequencing of small RNAs was carried out on plantlets subjected to severe abiotic stress using the Solexa technique. By combining the LeARN pipeline, data from the Plant microRNA database (PMRD) and Hevea EST sequences, we identified 48 conserved miRNA families already characterized in other plant species, and 10 putatively novel miRNA families. The results showed the most abundant size for miRNAs to be 24 nucleotides, except for seven families. Several MIR genes produced both 20-22 nucleotides and 23-27 nucleotides. The two miRNA class sizes were detected for both conserved and putative novel miRNA families, suggesting their functional duality. The EST databases were scanned with conserved and novel miRNA sequences. MiRNA targets were computationally predicted and analysed. The predicted targets involved in "responses to stimuli" and to "antioxidant" and "transcription activities" are presented. Conclusions Deep sequencing of small RNAs combined with transcriptomic data is a powerful tool for identifying conserved and novel miRNAs when the complete genome is not yet available. Our study provided additional information for evolutionary studies and revealed potentially specific regulation of the control of redox status in Hevea.

2012-01-01

296

Physiological and molecular responses to variation of light intensity in rubber Tree (Hevea brasiliensis Muell. Arg.).  

PubMed

Light is one of most important factors to plants because it is necessary for photosynthesis. In this study, physiological and gene expression analyses under different light intensities were performed in the seedlings of rubber tree (Hevea brasiliensis) clone GT1. When light intensity increased from 20 to 1000 µmol m(-2) s(-1), there was no effect on the maximal quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), indicating that high light intensity did not damage the structure and function of PSII reaction center. However, the effective photochemical quantum yield of PSII (Y(II)), photochemical quenching coefficient (qP), electron transfer rate (ETR), and coefficient of photochemical fluorescence quenching assuming interconnected PSII antennae (qL) were increased significantly as the light intensity increased, reached a maximum at 200 µmol m(-2) s(-1), but decreased from 400 µmol m(-2) s(-1). These results suggested that the PSII photochemistry showed an optimum performance at 200 µmol m(-2) s(-1) light intensity. The chlorophyll content was increased along with the increase of light intensity when it was no more than 400 µmol m(-2) s(-1). Since increasing light intensity caused significant increase in H2O2 content and decreases in the per unit activity of antioxidant enzymes SOD and POD, but the malondialdehyde (MDA) content was preserved at a low level even under high light intensity of 1000 µmol m(-2) s(-1), suggesting that high light irradiation did not induce membrane lipid peroxidation in rubber tree. Moreover, expressions of antioxidant-related genes were significantly up-regulated with the increase of light intensity. They reached the maximum expression at 400 µmol m(-2) s(-1), but decreased at 1000 µmol m(-2) s(-1). In conclusion, rubber tree could endure strong light irradiation via a specific mechanism. Adaptation to high light intensity is a complex process by regulating antioxidant enzymes activities, chloroplast formation, and related genes expressions in rubber tree. PMID:24586839

Wang, Li-feng

2014-01-01

297

Impact of age of rubber (Hevea brasiliensis) plantation on earthworm communities of West Tripura (India).  

PubMed

A comparative analysis of earthworm communities was carried out in the rubber plantations (Hevea brasiliensis) of different age groups in West Tripura to understand the impact of such exotic and monoculture plantation in biodiversity conservation. Earthworm communities were studied on monthly basis over a period of one year (2006-2007) in the 3, 10, 14, 20 and 25 year-old plantations. Among twelve earthworm species collected from the studied sites, six species belonged to Octochaetidae [Eutyphoeus assomensis Stephenson, Eutyphoeus comillahnus Michaelsen, Lennogaster chittagongensis (Stephensen), Octochaetona beatrix Gates, Dichogaster offinis Michaelsen, Lennogaster yeicus (Stephensen)], two species each to Megascolecidae [Metaphire houlleti (Perrier), Konchurio sp. 1] and Moniligastridae [Drowida nepalensis Michaelsen, Drawida papillifer papillifer Stephenson], one species each to Glossoscolecidae [Pontoscolex corethrurus (Muller)] and Ocnerodrilidae [Gordiodrilus elegans Beddard]. Exotic species P corethrurus, M. houlleti and native peregrine species like D. nepolensis and D. papillifer papillifer were distributed in all the age groups of plantation, while other species showed restricted distribution. P. corethrurus contributed more than 60% biomass and 70% density of earthworm communities in rubber plantation. With aging of rubber plantations both the densities and biomasses of earthworms increased. High contents of polyphenol, flavonoid and lignin in the litters of 3 and 10 year-old-rubber plantations through their effects on food intake, probably resulted to low biomass values of earthworms in those age groups of plantation. With further increase in the age of plantations beyond 10 years, polyphenol, flavonoid and lignin contents decreased. Accordingly the biomass of earthworms increased with increase in the age of plantation. Soil moisture increased with increase in the age of plantation and there was a good positive correlation between soil moisture and earthworm biomass (p < 0.01). Density, biomass and dominance of earthworms increased while species diversity, species richness and species evenness of earthworm community were decreased with increase in the age of rubber plantation. PMID:24006808

Chaudhuri, P S; Bhattacharjee, Subhalaxmi; Dey, Animesh; Chattopadhyay, Sharmila; Bhattacharya, Dipto

2013-01-01

298

Identification of the Hevea brasiliensis AP2/ERF superfamily by RNA sequencing  

PubMed Central

Background Rubber tree (Hevea brasiliensis) laticifers are the source of natural rubber. Rubber production depends on endogenous and exogenous ethylene (ethephon). AP2/ERF transcription factors, and especially Ethylene-Response Factors, play a crucial role in plant development and response to biotic and abiotic stresses. This study set out to sequence transcript expressed in various tissues using next-generation sequencing and to identify AP2/ERF superfamily in the rubber tree. Results The 454 sequencing technique was used to produce five tissue-type transcript libraries (leaf, bark, latex, embryogenic tissues and root). Reads from all libraries were pooled and reassembled to improve mRNA lengths and produce a global library. One hundred and seventy-three AP2/ERF contigs were identified by in silico analysis based on the amino acid sequence of the conserved AP2 domain from the global library. The 142 contigs with the full AP2 domain were classified into three main families (20 AP2 members, 115 ERF members divided into 11 groups, and 4 RAV members) and 3 soloist members. Fifty-nine AP2/ERF transcripts were found in latex. Alongside the microRNA172 already described in plants, eleven additional microRNAs were predicted to inhibit Hevea AP2/ERF transcripts. Conclusions Hevea has a similar number of AP2/ERF genes to that of other dicot species. We adapted the alignment and classification methods to data from next-generation sequencing techniques to provide reliable information. We observed several specific features for the ERF family. Three HbSoloist members form a group in Hevea. Several AP2/ERF genes highly expressed in latex suggest they have a specific function in Hevea. The analysis of AP2/ERF transcripts in Hevea presented here provides the basis for studying the molecular regulation of latex production in response to abiotic stresses and latex cell differentiation.

2013-01-01

299

The Latex of Hevea brasiliensis Contains High Levels of Both Chitinases and Chitinases/Lysozymes 1  

PubMed Central

The latex of the commercial rubber tree, Hevea brasiliensis, was fractionated by ultracentrifugation as described by G. F. J. Moir ([1959] Nature 184: 1626-1628) into a top layer of rubber particles, a cleared cytoplasm, and a pellet that contains primarily specialized vacuoles known as lutoids. The proteins in each fraction were resolved by two-dimensional gel electrophoresis. Both the pellet fraction and cleared cytoplasm contained large amounts of relatively few proteins, suggesting that laticifers serve a very specialized function in the plant. More than 75% of the total soluble protein in latex was found in the pellet fraction. Twenty-five percent of the protein in the pellet was identified as chitinases/lysozymes, which are capable of degrading the chitin component of fungal cell walls and the peptidoglycan component of bacterial cell walls. Both the chitinase and lysozyme activities were localized exclusively in the pellet or lutoid fraction. The chitinases/lysozymes were resolved into acidic and basic classes of proteins and further purified. An acidic protein (molecular mass 25.5 kD) represented 20% of the chitinase activity in latex; this protein lacked the low level of lysozyme activity that is associated with many plant chitinases. Six basic proteins, having both chitinase and lysozyme activities in various ratios and molecular mass of 27.5 or 26 kD, were resolved. Two of the basic proteins had very high lysozyme specific activities which were comparable to the specific activities reported for animal lysozymes. Like animal lysozymes, but unlike previously characterized plant chitinases/lysozymes, these basic chitinases/lysozymes were also capable of completely lysing or clearing suspensions of bacterial cell walls. These results suggest that laticifers may serve a defensive role in the plant. Images Figure 2 Figure 5

Martin, Melinda N.

1991-01-01

300

Organochlorine insecticide residues in the free-tailed bat (Tadarida brasiliensis) at Bracken Cave, Texas  

USGS Publications Warehouse

Fifty-nine free-tailed bats (Tadarida brasiliensis mexicana ) were collected at Bracken Cave, Texas, and analyzed for organochlorine insecticides and polychlorinated biphenyls (PCBs). Residues of DDE in the brain were greater in 12 young collected from the floor than in 15 young taken from the ceiling, but food deprivation, not higher residues in the brain, apparently caused young to fall....Among 18 pregnant females, residues of DDE and DDT were highest in yearlings. The first lactation by yearlings caused their residue loads to drop sharply. Thereafter, increasing age was accompanied by increasing residues but amounts generally did not exceed those in yearlings.....Residue levels in embryos were a function both of levels in the female parent and degree of embryonic development. Residues accumulated rapidly in nursing young, and lactating females may excrete from 1.3 to 16.2 (mean = 4.3) micrograms of DDE in milk per day. Maximum individual residue loads may be attained toward the end of nursing, and mobilization of these residues during southward migration may subject Bracken Cave free-tails to maximum lifetime residues in the brain....Comparison of our data with residue data for the free-tail population at Eagle Creek Cave (Arizona) in 1970 produced the following conclusions: ( 1) residues of DDE appeared similar in pregnant females, embryos, lactating females, and fallen young for the two populations; (2) residues of DDT and dieldrin appeared greater in pregnant females at Bracken Cave; (3) DDE and DDT occurred at greater levels in guano samples from Bracken Cave. On this basis, the population decline observed at Eagle Creek Cave between 1963 and 1969 does not appear to be related to the residues observed in the 1970 samples taken from that cave.

Clark, D.R., Jr.; Martin, C.O.; Swineford, D.M.

1975-01-01

301

Characterization and cytotoxic activity of sulfated derivatives of polysaccharides from Agaricus brasiliensis  

PubMed Central

Agaricus brasiliensis cell-wall polysaccharides isolated from fruiting body (FR) and mycelium (MI) and their respective sulfated derivatives (FR-S and MI-S) were chemically characterized using elemental analysis, TLC, FT-IR, NMR, HPLC, and thermal analysis. Cytotoxic activity was evaluated against A549 tumor cells by MTT and sulforhodamine assays. The average molecular weight (Mw) of FR and MI was estimated to be 609 and 310 kDa, respectively. FR-S (127 kDa) and MI-S (86 kDa) had lower Mw, probably due to hydrolysis occurred during the sulfation reaction. FR-S and MI-S presented ~14 % sulfur content in elemental analysis. Sulfation of samples was characterized by the appearance of two new absorption bands at 1253 and 810 cm?1 in the infrared spectra, related to S=O and C-S-O sulfate groups, respectively. Through 1H and 13C NMR analysis FR-S was characterized as a (1?6)-(1?3)-?-D-glucan fully sulfated at C-4 and C-6 terminal and partially sulfated at C-6 of (1?3)-?-D-glucan moiety. MI-S was shown to be a (1?3)-?-D-gluco-(1?2)-?-D-mannan, partially sulfated at C-2, C-3, C-4, and C-6, and fully sulfated at C-6 of the terminal residues. The combination of high degree of sulfation and low molecular weight was correlated with the increased cytotoxic activity (48 h of treatment) of both FR-S (EC50=605.6 ?g/mL) and MI-S (EC50=342.1 ?g/mL) compared to the non-sulfated polysaccharides FR and MI (EC50>1500 ?g/mL).

Cardozo, F. T. G. S.; Camelini, C. M.; Cordeiro, M. N. S.; Mascarello, A.; Malagoli, B. G.; Larsen, I.; Rossi, M. J.; Nunes, R. J.; Braga, F. C.; Brandt, C.R.; Simoes, C. M. O.

2014-01-01

302

Drosophila Regulate Yeast Density and Increase Yeast Community Similarity in a Natural Substrate  

PubMed Central

Drosophila melanogaster adults and larvae, but especially larvae, had profound effects on the densities and community structure of yeasts that developed in banana fruits. Pieces of fruit exposed to adult female flies previously fed fly-conditioned bananas developed higher yeast densities than pieces of the same fruits that were not exposed to flies, supporting previous suggestions that adult Drosophila vector yeasts to new substrates. However, larvae alone had dramatic effects on yeast density and species composition. When yeast densities were compared in pieces of the same fruits assigned to different treatments, fruits that developed low yeast densities in the absence of flies developed significantly higher yeast densities when exposed to larvae. Across all of the fruits, larvae regulated yeast densities within narrow limits, as compared to a much wider range of yeast densities that developed in pieces of the same fruits not exposed to flies. Larvae also affected yeast species composition, dramatically reducing species diversity across fruits, reducing variation in yeast communities from one fruit to the next (beta diversity), and encouraging the consistent development of a yeast community composed of three species of yeast (Candida californica, C. zemplinina, and Pichia kluvyeri), all of which were palatable to larvae. Larvae excreted viable cells of these three yeast species in their fecal pools, and discouraged the growth of filamentous fungi, processes which may have contributed to their effects on the yeast communities in banana fruits. These and other findings suggest that D. melanogaster adults and their larval offspring together engage in ‘niche construction’, facilitating a predictable microbial environment in the fruit substrates in which the larvae live and develop.

Stamps, Judy A.; Yang, Louie H.; Morales, Vanessa M.; Boundy-Mills, Kyria L.

2012-01-01

303

YMDB: the Yeast Metabolome Database.  

PubMed

The Yeast Metabolome Database (YMDB, http://www.ymdb.ca) is a richly annotated 'metabolomic' database containing detailed information about the metabolome of Saccharomyces cerevisiae. Modeled closely after the Human Metabolome Database, the YMDB contains >2000 metabolites with links to 995 different genes/proteins, including enzymes and transporters. The information in YMDB has been gathered from hundreds of books, journal articles and electronic databases. In addition to its comprehensive literature-derived data, the YMDB also contains an extensive collection of experimental intracellular and extracellular metabolite concentration data compiled from detailed Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR) metabolomic analyses performed in our lab. This is further supplemented with thousands of NMR and MS spectra collected on pure, reference yeast metabolites. Each metabolite entry in the YMDB contains an average of 80 separate data fields including comprehensive compound description, names and synonyms, structural information, physico-chemical data, reference NMR and MS spectra, intracellular/extracellular concentrations, growth conditions and substrates, pathway information, enzyme data, gene/protein sequence data, as well as numerous hyperlinks to images, references and other public databases. Extensive searching, relational querying and data browsing tools are also provided that support text, chemical structure, spectral, molecular weight and gene/protein sequence queries. Because of S. cervesiae's importance as a model organism for biologists and as a biofactory for industry, we believe this kind of database could have considerable appeal not only to metabolomics researchers, but also to yeast biologists, systems biologists, the industrial fermentation industry, as well as the beer, wine and spirit industry. PMID:22064855

Jewison, Timothy; Knox, Craig; Neveu, Vanessa; Djoumbou, Yannick; Guo, An Chi; Lee, Jacqueline; Liu, Philip; Mandal, Rupasri; Krishnamurthy, Ram; Sinelnikov, Igor; Wilson, Michael; Wishart, David S

2012-01-01

304

Cell size control in yeast  

PubMed Central

Cell size is an important adaptive trait that influences nearly all aspects of cellular physiology. Despite extensive characterization of the cell cycle regulatory network, the molecular mechanismscoupling growth to division, and thereby controlling cell size, have remained elusive. Recent workin yeast has reinvigorated the size control field and suggested provocative mechanisms forthe distinct functions of setting and sensing cell size. Further examination of size sensing models based on spatial gradients and molecular titration, coupled with elucidation of the pathways responsible for nutrient-modulated target size, may reveal the fundamental principles of eukaryotic cell size control.

Turner, Jonathan J.; Ewald, Jennifer C.; Skotheim, Jan M.

2012-01-01

305

Characterisation of a Marine Bacterium Vibrio Brasiliensis T33 Producing N-acyl Homoserine Lactone Quorum Sensing Molecules.  

PubMed

N-acylhomoserine lactones (AHL) plays roles as signal molecules in quorum sensing (QS) in most Gram-negative bacteria. QS regulates various physiological activities in relation with population density and concentration of signal molecules. With the aim of isolating marine water-borne bacteria that possess QS properties, we report here the preliminary screening of marine bacteria for AHL production using Chromobacterium violaceum CV026 as the AHL biosensor. Strain T33 was isolated based on preliminary AHL screening and further identified by using 16S rDNA sequence analysis as a member of the genus Vibrio closely related to Vibrio brasiliensis. The isolated Vibrio sp. strain T33 was confirmed to produce N-hexanoyl-l-homoserine lactone (C6-HSL) and N-(3-oxodecanoyl)-l-homoserine lactone (3-oxo-C10 HSL) through high resolution tandem mass spectrometry analysis. We demonstrated that this isolate formed biofilms which could be inhibited by catechin. To the best of our knowledge, this is the first report that documents the production of these AHLs by Vibrio brasiliensis strain T33. PMID:25006994

Tan, Wen-Si; Yunos, Nina Yusrina Muhamad; Tan, Pui-Wan; Mohamad, Nur Izzati; Adrian, Tan-Guan-Sheng; Yin, Wai-Fong; Chan, Kok-Gan

2014-01-01

306

Effects of light intensity on the distribution of anthocyanins in Kalanchoe brasiliensis Camb. and Kalanchoe pinnata (Lamk.) Pers.  

PubMed

This paper compares two medicinal species of Kalanchoe, which are often used interchangeably by the population, regarding the distribution of anthocyanins under the influence of four luminosity levels for 6 months. For the morphoanatomical analysis, the 6th stem node of each plant was sectioned. Usual histochemical tests revealed the presence of anthocyanins by cross sections of the stems, petioles and leaf blades. The petioles and leaf blades were submitted to the extraction with acidified methanol, and the anthocyanins were quantified by spectrophotometric readings. At the macroscopic level, it was noticed for both species a higher presence of anthocyanins in stems and petioles of plants under full sunlight. The microscopy of K. brasiliensis stems evidenced the deposition of anthocyanins in the subjacent tissue to the epidermis and cortex, which increased with light intensity. In K. pinnata a subepidermal collenchyma was observed, which interfered in the visualization of anthocyanins. In petioles and leaf blades of K. brasiliensis the deposition of anthocyanins was peripheral, and in K. pinnata it was also throughout the cortex. The quantification of anthocyanins in petioles showed in 70% of light higher averages than in 25%, but in leaf blades there were no significant results. This study contributes to the pharmacognosy of Kalanchoe and it is sustained by the description of flavonoids as biological markers of the genus. PMID:22441611

Cruz, Bruna P; Chedier, Luciana M; Peixoto, Paulo H P; Fabri, Rodrigo L; Pimenta, Daniel S

2012-03-01

307

Cysteine protease of the nematode Nippostrongylus brasiliensis preferentially evokes an IgE/IgG1 antibody response in rats.  

PubMed Central

Some cysteine proteases such as papain and those of mites and schistosomes have potent allergenic properties. To clarify the allergenicity of nematode cysteine proteases, the enzyme was purified from the intestinal nematode Nippostrongylus brasiliensis using cation exchange chromatography and gel filtration chromatography. The purified protease, of 16 kD and pI 8.5, showed maximum enzyme activity at pH 5.5 and substrate preference for Z-Phe-Arg-MCA. The specific inhibitors of cysteine protease leupeptin, iodoacetic acid, and E-64, completely suppressed the activity, indicating that the purified enzyme belongs to the cysteine protease family. Cysteine protease activity was found not only in somatic extract, but also in the excretory-secretory (ES) product of the nematode. When anti-cysteine protease immunoglobulin isotypes were examined in sera from rats infected with N. brasiliensis, a high level of IgG1 and a lower level of IgE antibody were detected. Depletion of IgG antibodies from the sera using protein G affinity columns resulted in a marked increase in reactivity of anti-cysteine protease IgE with the antigen, possibly due to the removal of competing IgG antibodies. In contrast to IgE and IgG1, production of anti-cysteine protease IgG2a was negligible. These results indicate that the nematode cysteine protease preferentially evokes an IgE/IgG1 antibody response. Images Fig. 2

Kamata, I; Yamada, M; Uchikawa, R; Matsuda, S; Arizono, N

1995-01-01

308

Adjuvant activity of Quillaja brasiliensis saponins on the immune responses to bovine herpesvirus type 1 in mice.  

PubMed

The chemical characterization of aqueous extracts (AE) of barks, leaves and branches and the saponin fraction denominated QB-90 obtained from Quillaja brasiliensis, a native species from Southern Brazil, show remarkable similarities to Quillaja saponaria saponins which are known as adjuvants in vaccine formulations. In vivo toxicity assays of AE and QB-90 showed not to be lethal for mice in doses ranging from 50 to 1600 microg and 50-400 microg, respectively. Experimental vaccines prepared with bovine herpesvirus type 1 (BHV-1) antigen and either AE (barks 100 microg, leaves 400 microg, branches 400 microg) or QB-90 (100 microg) were able to enhance the immune responses of mice in a comparable manner to saponins from Q. saponaria (QuilA, 100 microg). BHV-1 specific IgG, IgG1 and IgG2a antibody levels in serum were also significantly enhanced by AE, QB-90 and QuilA compared to control group (p<0.05). These results showed that AE and QB-90 from Q. brasiliensis are potential candidates as adjuvants in vaccines. PMID:16887242

Fleck, Juliane D; Kauffmann, Carla; Spilki, Fernando; Lencina, Claiton L; Roehe, Paulo M; Gosmann, Grace

2006-11-30

309

Ecology of Triatoma brasiliensis in northeastern Brazil: seasonal distribution, feeding resources, and Trypanosoma cruzi infection in a sylvatic population.  

PubMed

We assessed some ecological parameters of Triatoma brasiliensis in rock piles in the state of Ceará during the rainy and dry seasons. The greatest density was in April (median = 12.5 triatomines/site). The greatest abundance was in December, when the insects were more dispersed and the density per site was lower (6 triatomines/site). The nutritional status of females and 5th instar nymphs was increased in July. The rate of T. cruzi infection reached its highest peak in July (10.9%). ELISA revealed that the principal food sources were birds (33.1%), followed by armadillos (18.8%). Food sources were more frequently identified during the rainy season. T. brasiliensis specimens collected in the drought tended to: i) present lower rates of T. cruzi infection and gut content reactivity to tested antisera, ii) have a poorer nutritional status, iii) exhibit lower fecundity, iv) be more dispersed among the studied collection sites, and v) be more abundant and easily collected in the surface of the rocks, possibly reflecting an increased searching for blood meals. Such findings underscore epidemiological concerns and allow inferences about the season when triatomines can more frequently invade the peridomestic environment in search of food and recolonize artificial structures. PMID:21175946

Sarquis, Otilia; Carvalho-Costa, Filipe A; Oliveira, Lívia Silva; Duarte, Rosemere; D Andrea, Paulo Sergio; de Oliveira, Tiago Guedes; Lima, Marli Maria

2010-12-01

310

Desulfovibrio brasiliensis sp. nov., a moderate halophilic sulfate-reducing bacterium from Lagoa Vermelha (Brazil) mediating dolomite formation.  

PubMed

A novel halotolerant sulfate-reducing bacterium, Desulfovibrio brasiliensis strain LVform1, was isolated from sediments of a dolomite-forming hypersaline coastal lagoon, Lagoa Vermelha, in the state of Rio de Janeiro, Brazil. The cells are vibrio-shaped and 0.30 to 0.45 microm by 1.0 to 3.5 microm in size. These bacteria mediate the precipitation of dolomite [CaMg(CO3)2] in culture experiments. The strain was identified as a member of the genus Desulfovibrio in the delta-subclass of the Proteobacteria on the basis of its 16S rRNA gene sequence, its physiological and morphological properties. Strain LVform1 is obligate sodium-dependent and grows at NaCl concentrations of up to 15%. The 16S rRNA sequence revealed that this strain is closely related to Desulfovibrio halophilus (96.2% similarity) and to Desulfovibrio oxyclinae (96.8% similarity), which were both isolated from Solar Lake, a hypersaline coastal lake in the Sinai, Egypt. Strain LVform1 is barotolerant, growing under pressures of up to 370 bar (37 MPa). We propose strain LVform1 to be the type strain of a novel species of the genus Desulfovibrio, Desulfovibrio brasiliensis (type strain LVform1 = DSMZ No. 15816 and JCM No. 12178). The GenBank/EMBL accession number for the 16S rDNA sequence of strain LVform1 is AJ544687. PMID:15856133

Warthmann, Rolf; Vasconcelos, Crisogono; Sass, Henrik; McKenzie, Judith A

2005-06-01

311

Identification of laticifer-specific genes and their promoter regions from a natural rubber producing plant Hevea brasiliensis.  

PubMed

Latex, the milky cytoplasm of highly differentiated cells called laticifers, from Hevea brasiliensis is a key source of commercial natural rubber production. One way to enhance natural rubber production would be to express genes involved in natural rubber biosynthesis by a laticifer-specific overexpression system. As a first step to identify promoters which could regulate the laticifer-specific expression, we identified random clones from a cDNA library of H. brasiliensis latex, resulting in 4325 expressed sequence tags (ESTs) assembled into 1308 unigenes (692 contigs and 617 singletons). Quantitative analyses of the transcription levels of high redundancy clones in the ESTs revealed genes highly and predominantly expressed in laticifers, such as Rubber Elongation Factor (REF), Small Rubber Particle Protein and putative protease inhibitor proteins. HRT1 and HRT2, cis-prenyltransferases involved in rubber biosynthesis, was also expressed predominantly in laticifers, although these transcript levels were 80-fold lower than that of REF. The 5'-upstream regions of these laticifer-specific genes were cloned and analyzed in silico, revealing seven common motifs consisting of eight bases. Furthermore, transcription factors specifically expressed in laticifers were also identified. The common motifs in the laticifer-specific genes and the laticifer-specific transcription factors are potentially involved in the regulation of gene expression in laticifers. PMID:25017153

Aoki, Yuichi; Takahashi, Seiji; Takayama, Daisuke; Ogata, Yoshiyuki; Sakurai, Nozomu; Suzuki, Hideyuki; Asawatreratanakul, Kasem; Wititsuwannakul, Dhirayos; Wititsuwannakul, Rapepun; Shibata, Daisuke; Koyama, Tanetoshi; Nakayama, Toru

2014-08-01

312

Behavioural evidence of male volatile pheromones in the sex-role reversed wolf spiders Allocosa brasiliensis and Allocosa alticeps  

NASA Astrophysics Data System (ADS)

The use of chemical signals in a sexual context is widespread in the animal kingdom. Most studies in spiders report the use of female pheromones that attract potential sexual partners. Allocosa brasiliensis and Allocosa alticeps are two burrowing wolf spiders that show sex-role reversal. Females locate male burrows and initiate courtship before males perform any detectable visual or vibratory signal. So, females of these species would be detecting chemical or mechanical cues left by males. Our objective was to explore the potential for male pheromones to play a role in mate detection in A. brasiliensis and A. alticeps. We designed two experiments. In Experiment 1, we tested the occurrence of male contact pheromones by evaluating female courtship when exposed to empty burrows constructed by males or females (control). In Experiment 2, we tested the existence of male volatile pheromones by evaluating female behaviour when exposed to artificial burrows connected to tubes containing males, females or empty tubes (control). Our results suggest the occurrence of male volatile pheromones that trigger female courtship in both Allocosa species. The sex-role reversal postulated for these wolf spiders could be driving the consequent reversal in typical pheromone-emitter and detector roles expected for spiders.

Aisenberg, Anita; Baruffaldi, Luciana; González, Macarena

2010-01-01

313

Prevention of Yeast Spoilage in Feed and Food by the Yeast Mycocin HMK  

PubMed Central

The yeast Williopsis mrakii produces a mycocin or yeast killer toxin designated HMK; this toxin exhibits high thermal stability, high pH stability, and a broad spectrum of activity against other yeasts. We describe construction of a synthetic gene for mycocin HMK and heterologous expression of this toxin in Aspergillus niger. Mycocin HMK was fused to a glucoamylase protein carrier, which resulted in secretion of biologically active mycocin into the culture media. A partial purification protocol was developed, and a comparison with native W. mrakii mycocin showed that the heterologously expressed mycocin had similar physiological properties and an almost identical spectrum of biological activity against a number of yeasts isolated from silage and yoghurt. Two food and feed production systems prone to yeast spoilage were used as models to assess the ability of mycocin HMK to act as a biocontrol agent. The onset of aerobic spoilage in mature maize silage was delayed by application of A. niger mycocin HMK on opening because the toxin inhibited growth of the indigenous spoilage yeasts. This helped maintain both higher lactic acid levels and a lower pH. In yoghurt spiked with dairy spoilage yeasts, A. niger mycocin HMK was active at all of the storage temperatures tested at which yeast growth occurred, and there was no resurgence of resistant yeasts. The higher the yeast growth rate, the more effective the killing action of the mycocin. Thus, mycocin HMK has potential applications in controlling both silage spoilage and yoghurt spoilage caused by yeasts.

Lowes, K. F.; Shearman, C. A.; Payne, J.; MacKenzie, D.; Archer, D. B.; Merry, R. J.; Gasson, M. J.

2000-01-01

314

IL-4R?-responsive smooth muscle cells contribute to initiation of TH2 immunity and pulmonary pathology in Nippostrongylus brasiliensis infections.  

PubMed

Nippostrongylus brasiliensis infections generate pulmonary pathologies that can be associated with strong T(H)2 polarization of the host's immune response. We present data demonstrating N. brasiliensis-driven airway mucus production to be dependent on smooth muscle cell interleukin 4 receptor-? (IL-4R?) responsiveness. At days 7 and 10 post infection (PI), significant airway mucus production was found in IL-4R?(-/lox) control mice, whereas global knockout (IL-4R?(-/-)) and smooth muscle-specific IL-4R?-deficient mice (SM-MHC(Cre) IL-4R?(-/lox)) showed reduced airway mucus responses. Furthermore, interleukin (IL)-13 and IL-5 cytokine production in SM-MHC(Cre) IL-4R?(-/lox) mice was impaired along with a transient reduction in T-cell numbers in the lung. In vitro treatment of smooth muscle cells with secreted N. brasiliensis excretory-secretory antigen (NES) induced IL-6 production. Decreased protein kinase C (PKC)-dependent smooth muscle cell proliferation associated with cell cycle arrest was found in cells stimulated with NES. Together, these data demonstrate that both IL-4R? and NES-driven responses by smooth muscle cells make important contributions in initiating T(H)2 responses against N. brasiliensis infections. PMID:20737001

Horsnell, W G C; Vira, A; Kirstein, F; Mearns, H; Hoving, J C; Cutler, A J; Dewals, B; Myburgh, E; Kimberg, M; Arendse, B; White, N; Lopata, A; Burger, P E; Brombacher, F

2011-01-01

315

Effect of nutritional and environmental conditions on the production of exo-polysaccharide of Agaricus brasiliensis by submerged fermentation and its antitumor activity  

Microsoft Academic Search

Mushrooms have become attractive as a functional food and as a source for the development of drugs and nutraceuticals. A. brasiliensis is considered as the best among them. There are several published works on the fruiting bodies of this mushroom, showing high antitumor activity. The mycelium polysaccharide and exo-polysaccharide (EPS) of this mushroom also demonstrated a strong antitumor action. However,

Leifa Fan; Andrea Thomaz Soccol; Ashok Pandey; Carlos Ricardo Soccol

2007-01-01

316

Evaluation of Royal Sun Agaricus, Agaricus brasiliensis S. Wasser et al., aqueous extract in mice challenged with Salmonella enterica serovar Typhimurium.  

PubMed

This study investigated the effects of Agaricus brasiliensis S. Wasser et al. (=Agaricus blazei Murrill sensu Heinem.) aqueous extract on small intestinal sIgA levels, serum TNF-alpha, IFN-gamma and IL-10 levels, splenic index, bacterial translocation, and histology of small intestine, spleen, and liver from mice orally challenged with 10(6) CFU of Salmonella enterica serovar Typhimurium (SEST). Splenic index values as well as sIgA, TNF-alpha, IFN-gamma, and IL-10 levels were not affected by either A. brasiliensis aqueous extract treatment or by pathogenic challenge. Typical colonies of SEST were recovered from liver, spleen, and mesenteric lymph nodes of challenged animals, but there was no significant difference in this translocation between groups treated or not with A. brasiliensis aqueous extract. Translocation was confirmed by histopathological analysis in mice challenged with SEST, which showed small and diffuse foci of mixed inflammatory infiltrate in hepatic parenchyma. In conclusion, A. brasiliensis aqueous extract as tested in the present study did not influence any of the variables selected to evaluate in vivo its immunomodulatory effect suggested in the literature. PMID:22135880

Fantuzzi, Elisabete; Anastácio, Lucilene Rezende; Nicoli, Jacques Robert; de Paula, Sérgio Oliveira; Arantes, Rosa Maria Esteves; Vanetti, Maria Cristina Dantas

2011-01-01

317

Fermentation studies using Saccharomyces diastaticus yeast strains  

SciTech Connect

The yeast species, Saccharomyces diastaticus, has the ability to ferment starch and dextrin, because of the extracellular enzyme, glucoamylase, which hydrolyzes the starch/dextrin to glucose. A number of nonallelic genes--DEX 1, DEX 2, and dextrinase B which is allelic to STA 3--have been isolated, which impart to the yeast the ability to ferment dextrin. Various diploid yeast strains were constructed, each being either heterozygous or homozygous for the individual dextrinase genes. Using 12 (sup 0) plato hopped wort (30% corn adjunct) under agitated conditions, the fermentation rates of the various diploid yeast strains were monitored. A gene-dosage effect was exhibited by yeast strains containing DEX 1 or DEX 2, however, not with yeast strains containing dextrinase B (STA 3). The fermentation and growth rates and extents were determined under static conditions at 14.4 C and 21 C. With all yeast strains containing the dextrinase genes, both fermentation and growth were increased at the higher incubation temperature. Using 30-liter fermentors, beer was produced with the various yeast strains containing the dextrinase genes and the physical and organoleptic characteristics of the products were determined. The concentration of glucose in the beer was found to increase during a 3-mo storage period at 21 C, indicating that the glucoamylase from Saccharomyces diastaticus is not inactivated by pasteurization. (Refs. 36).

Erratt, J.A.; Stewart, G.G.

1981-01-01

318

Characterization of wine yeasts for ethanol production  

Microsoft Academic Search

Selected wine yeasts were tested for their ethanol and sugar tolerance, and for their fermentative capacity. Growth (µ) and fermentation rates (?) were increasingly inhibited by increasing ethanol and glucose concentrations, “flor” yeasts being the least inhibited. Except in the latter strains, the ethanol production rate was accelerated by adding the glucose stepwise. The best fermenting strains selected in laboratory

Juan Jiménez; Tahía Benítez

1986-01-01

319

Characterization of wine yeasts for ethanol production  

Microsoft Academic Search

Summary Selected wine yeasts were tested for their ethanol and sugar tolerance, and for their fermentative capacity. Growth (µ) and fermentation rates (?) were increasingly inhibited by increasing ethanol and glucose concentrations, “flor” yeasts being the least inhibited. Except in the latter strains, the ethanol production rate was accelerated by adding the glucose stepwise. The best fermenting strains selected in

Juan Jiménez; Tahía Benítez

1986-01-01

320

Yeast Sporulation on Two Commonly Available Media.  

National Technical Information Service (NTIS)

In attempting to produce sporulation in some yeast strains, it was found that Trypticase Soy Broth (TSB; BBL) plus agar (1.5%) and Nutrient Agar (NA; BBL) induced fair to good sporulation of commercial bakers' yeast in 3 days, after two or three necessary...

W. P. Iverson

1967-01-01

321

On the origins of wine yeast  

Microsoft Academic Search

There is still a lack of agreement concerning the relative contribution of wine yeast that may originate in the vineyard compared to that which may originate in the cellar. Part of this controversy is due to the extreme difficulty of finding Saccharomyces cerevisiae on the grapes. We estimate that only about one in one-thousand grape berries carries wine yeast. However,

Robert Mortimer; Mario Polsinelli

1999-01-01

322

Yeasts are essential for cocoa bean fermentation.  

PubMed

Cocoa beans (Theobroma cacao) are the major raw material for chocolate production and fermentation of the beans is essential for the development of chocolate flavor precursors. In this study, a novel approach was used to determine the role of yeasts in cocoa fermentation and their contribution to chocolate quality. Cocoa bean fermentations were conducted with the addition of 200ppm Natamycin to inhibit the growth of yeasts, and the resultant microbial ecology and metabolism, bean chemistry and chocolate quality were compared with those of normal (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii and Kluyveromyces marxianus, the lactic acid bacteria Lactobacillus plantarum and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in the control fermentation. In fermentations with the presence of Natamycin, the same bacterial species grew but yeast growth was inhibited. Physical and chemical analyses showed that beans fermented without yeasts had increased shell content, lower production of ethanol, higher alcohols and esters throughout fermentation and lesser presence of pyrazines in the roasted product. Quality tests revealed that beans fermented without yeasts were purplish-violet in color and not fully brown, and chocolate prepared from these beans tasted more acid and lacked characteristic chocolate flavor. Beans fermented with yeast growth were fully brown in color and gave chocolate with typical characters which were clearly preferred by sensory panels. Our findings demonstrate that yeast growth and activity were essential for cocoa bean fermentation and the development of chocolate characteristics. PMID:24462702

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2014-03-17

323

Oily yeasts as oleaginous cell factories.  

PubMed

Oily yeasts have been described to be able to accumulate lipids up to 20% of their cellular dry weight. These yeasts represent a minor proportion of the total yeast population, and only 5% of them have been reported as able to accumulate more than 25% of lipids. The oily yeast genera include Yarrowia, Candida, Rhodotorula, Rhodosporidium, Cryptococcus, Trichosporon, and Lipomyces. More specifically, examples of oleaginous yeasts include the species: Lipomyces starkeyi, Rhodosporidium toruloides, Rhodotorula glutinis, and Yarrowia lipolytica. Yeast do exhibit advantages for lipid production over other microbial sources, namely, their duplication times are usually lower than 1 h, are much less affected than plants by season or climate conditions, and their cultures are more easily scaled up than those of microalgae. Additionally, some oily yeasts have been reported to accumulate oil up to 80% of their dry weight and can indeed generate different lipids from different carbon sources or from lipids present in the culture media. Thus, they can vary their lipid composition by replacing the fatty acids present in their triglycerides. Due to the diversity of microorganisms and growth conditions, oily yeasts can be useful for the production of triglycerides, surfactants, or polyunsaturated fatty acids. PMID:21465305

Ageitos, Jose Manuel; Vallejo, Juan Andres; Veiga-Crespo, Patricia; Villa, Tomas G

2011-05-01

324

Can yeast transcriptomics help improve wine fermentation?  

Microsoft Academic Search

Wine fermentation is a dynamic and complex process in which the yeast cell is subjected to multiple stress conditions. A successful adaptation involves changes in gene expression profiles where a large number of genes are up- or down-regulated. Functional genomic approaches are com- monly used to obtain global gene expression profiles, providing a comprehensive view of yeast physiology. We used

C. Varela; J. Cárdenas; E. Agosin

325

Production of food and fodder yeasts.  

PubMed

A decade or so ago, there was considerable interest in developing single cell protein production from raw materials. Many factors have influenced the development of fodder yeast technology, notably the biochemistry and physiology of the yeast. It is shown that those considerations have led to the choice of a continuous fermentation technology. PMID:1733522

Boze, H; Moulin, G; Galzy, P

1992-01-01

326

CYGD: the Comprehensive Yeast Genome Database  

Microsoft Academic Search

The Comprehensive Yeast Genome Database (CYGD) compiles a comprehensive data resource for information on the cellular functions of the yeast Saccharomyces cerevisiae and related species, cho- sen as the best understood model organism for eukar- yotes. The database serves as a common resource generated by a European consortium, going beyond the provision of sequence information and functional annotations on individual

Ulrich Güldener; Martin Münsterkötter; Gabi Kastenmüller; Normann Strack; Jacques Van Helden; Christian Lemer; J. Richelles; Shoshana J. Wodak; J. García-martínez; J. E. Pérez-ortín; Holger Michael; Andreas Kaps; E. Talla; Bernard Dujon; B. André; J. L. Souciet; J. De Montigny; E. Bon; C. Gaillardin; Hans-werner Mewes

2005-01-01

327

Yeast: An Experimental Organism for Modern Biology.  

ERIC Educational Resources Information Center

Discusses the applicability and advantages of using yeasts as popular and ideal model systems for studying and understanding eukaryotic biology at the cellular and molecular levels. Cites experimental tractability and the cooperative tradition of the research community of yeast biologists as reasons for this success. (RT)

Botstein, David; Fink, Gerald R.

1988-01-01

328

Polysaccharides from Agaricus bisporus and Agaricus brasiliensis show similarities in their structures and their immunomodulatory effects on human monocytic THP-1 cells  

PubMed Central

Background Mushroom polysaccharides have traditionally been used for the prevention and treatment of a multitude of disorders like infectious illnesses, cancers and various autoimmune diseases. Crude mushroom extracts have been tested without detailed chemical analyses of its polysaccharide content. For the present study we decided to chemically determine the carbohydrate composition of semi-purified extracts from 2 closely related and well known basidiomycete species, i.e. Agaricus bisporus and A. brasiliensis and to study their effects on the innate immune system, in particular on the in vitro induction of pro-inflammatory cytokines, using THP-1 cells. Methods Mushroom polysaccharide extracts were prepared by hot water extraction and precipitation with ethanol. Their composition was analyzed by GC-MS and NMR spectroscopy. PMA activated THP-1 cells were treated with the extracts under different conditions and the production of pro-inflammatory cytokines was evaluated by qPCR. Results Semi-purified polysaccharide extracts of A. bisporus and A. brasiliensis (= blazei) were found to contain (1?6),(1?4)-linked ?-glucan, (1?6)-linked ?-glucan, and mannogalactan. Their proportions were determined by integration of 1H-NMR signs, and were considerably different for the two species. A. brasiliensis showed a higher content of ?-glucan, while A. bisporus presented mannogalactan as its main polysaccharide. The extracts induced a comparable increase of transcription of the pro-inflammatory cytokine genes IL-1? and TNF-? as well as of COX-2 in PMA differentiated THP-1 cells. Pro-inflammatory effects of bacterial LPS in this assay could be reduced significantly by the simultaneous addition of A. brasiliensis extract. Conclusions The polysaccharide preparations from the closely related species A. bisporus and A. brasiliensis show major differences in composition: A. bisporus shows high mannogalactan content whereas A. brasiliensis has mostly ?-glucan. Semi-purified polysaccharide extracts from both Agaricus species stimulated the production of pro-inflammatory cytokines and enzymes, while the polysaccharide extract of A. brasiliensis reduced synthesis of these cytokines induced by LPS, suggesting programmable immunomodulation.

2011-01-01

329

New search for pectolytic yeasts.  

PubMed

A new screening method for pectin-depolymerizing microorganisms is described. The method is based on precipitation of non-hydrolyzed citrus pectin with hexadecyltrimethylammonium bromide in a medium solidified with a bacterial gelling gum. A substrate depolymerized by the secreted enzymes does not precipitate, and the positive strains thus show transparent areas around the colonies. The method was used to screen 300 yeast and yeast-like microorganisms belonging to 52 different genera. The secretion of pectin-depolymerizing enzymes occurred with different frequencies in 13 genera (69 positive strains of 207 tested), the lowest frequency being found in the genus Candida (13 positive out of 125 strains tested) and the highest frequency in the genera Aureobasidium (4 of 6) Cryptococcus (29 of 38), Geotrichum (4 of 9), Kluyveromyces (5 of 5), Rhodosporidium (2 of 2), Leucosporidium (2 of 2), Trichosporon (3 of 6) and Ustilago (2 of 2). Strains giving the highest number of harvested cells after growth on pectin in a liquid medium have been identified. PMID:8549997

Biely, P; Sláviková, E

1994-01-01

330

Growing yeast into cylindrical colonies.  

PubMed

Microorganisms often form complex multicellular assemblies such as biofilms and colonies. Understanding the interplay between assembly expansion, metabolic yield, and nutrient diffusion within a freely growing colony remains a challenge. Most available data on microorganisms are from planktonic cultures, due to the lack of experimental tools to control the growth of multicellular assemblies. Here, we propose a method to constrain the growth of yeast colonies into simple geometric shapes such as cylinders. To this end, we designed a simple, versatile culture system to control the location of nutrient delivery below a growing colony. Under such culture conditions, yeast colonies grow vertically and only at the locations where nutrients are delivered. Colonies increase in height at a steady growth rate that is inversely proportional to the cylinder radius. We show that the vertical growth rate of cylindrical colonies is not defined by the single-cell division rate, but rather by the colony metabolic yield. This contrasts with cells in liquid culture, in which the single-cell division rate is the only parameter that defines the population growth rate. This method also provides a direct, simple method to estimate the metabolic yield of a colony. Our study further demonstrates the importance of the shape of colonies on setting their expansion. We anticipate that our approach will be a starting point for elaborate studies of the population dynamics, evolution, and ecology of microbial colonies in complex landscapes. PMID:24853750

Vulin, Clément; Di Meglio, Jean-Marc; Lindner, Ariel B; Daerr, Adrian; Murray, Andrew; Hersen, Pascal

2014-05-20

331

Antifungal resistance in yeast vaginitis.  

PubMed Central

The increased number of vaginal yeast infections in the past few years has been a disturbing trend, and the scientific community has been searching for its etiology. Several theories have been put forth to explain the apparent increase. First, the recent widespread availability of low-dosage, azole-based over-the-counter antifungal medications for vaginal yeast infections encourages women to self-diagnose and treat, and women may be misdiagnosing themselves. Their vaginitis may be caused by bacteria, parasites or may be a symptom of another underlying health condition. As a result, they may be unnecessarily and chronically expose themselves to antifungal medications and encourage fungal resistance. Second, medical technology has increased the life span of seriously immune compromised individuals, yet these individuals are frequently plagued by opportunistic fungal infections. Long-term and intense azole-based antifungal treatment has been linked to an increase in resistant Candida and non-Candida species. Thus, the future of limiting antifungal resistance lies in identifying the factors promoting resistance and implementing policies to prevent it.

Dun, E.

1999-01-01

332

Production of ethanol by immobilized yeast cells  

SciTech Connect

Saccharomyces cerevisiae cells were immobilized in calcium alginate beads for use in the continuous production of ethanol. Yeasts were grown in medium supplemented with ethanol to selectively screen for a culture which showed the greatest tolerance to ethanol inhibition. Yeast beads were produced from a yeast slurry containing 1.5% alginate (w/v) which was added as drops to a 0.05M CaCl2 solution. To determine their optimum fermentation parameters, ethanol production using glucose as a substrate was monitored in batch systems at varying physiological conditions (temperature,pH, ethanol concentration), cell densities, and gel concentrations. The data obtained were compared to optimum free cell ethanol fermentation parameters. The immobilized yeast cells were examined in a packed-bed reactor system operated under optimized parameters derived from batch-immobilized yeast cell experiments. Ethanol production rates, as well as residual sugar concentrations were monitored at different feedstock flow rates. (Refs. 13).

Williams, D.; Munnecke, D.M.

1981-08-01

333

Chromosomal structures of bottom fermenting yeasts.  

PubMed

A genomic comparison of bottom fermenting yeasts was performed by pulsed-field gel electrophoresis and Southern blot analysis with some S. cerevisiae gene probes. We confirmed that strains of bottom fermenting yeast have four chromosomes originating from S. bayanus. Since the structures of these chromosomes were recombined with S. cerevisiae chromosomes, these S. bayanus chromosomes could be differentiated from S. cerevisiae chromosomes using Southern hybridization. Our Southern hybridization results indicate that bottom fermenting yeasts have both chromosomes originating from both S. cerevisiae and S. bayanus. It was reconfirmed that top fermenting yeast should be classified as S. cerevisiae, based on the chromosomal structure. The chromosomal structure of S. pastorianus CBS1538, the type stain of S. pastorianus, was also investigated. This strain has chromosomes originating only from S. bayanus. S. carlsbergensis CBS1513 has chromosomes originating from both S. cerevisiae and S. bayanus. From these results, we contend that bottom fermenting yeasts should be classified as S. carlsbergensis. PMID:10553286

Yamagishi, H; Ogata, T

1999-09-01

334

Selection of antibody fragments by yeast display.  

PubMed

The critical need for renewable, high-quality affinity reagents in biological research, as well as for diagnostic and therapeutic applications, has required the development of new platforms of discovery. Yeast display is one of the main methods of in vitro display technology with phage display. Yeast display has been chosen by numerous groups to refine both affinity and specificity of antibodies because it enables fine discrimination between mutant clones of similar affinity. In addition, the construction of display libraries of antibody fragments in yeast permit to sample the immune antibody repertoire more fully than using phage. This chapter gives an updated overview of the available systems of yeast display platforms and libraries, followed up by technical descriptions of selection methods of antibody fragments by yeast display. PMID:22907357

Scholler, Nathalie

2012-01-01

335

The cochlea of Tadarida brasiliensis: specialized functional organization in a generalized bat.  

PubMed

Tadarida brasiliensis mexicana employs a broad-band sonar system at frequencies between 80 and 20 kHz and is characterized by non-specialized hearing capabilities. The cochlear frequency map was determined with extracellular horseradish peroxidase tracing in relation to quantitative morphological data obtained with light, scanning and transmission electron microscopy. These data reveal distinct species characteristic specializations clearly separate from the patterns observed in other bats with either broad-band or narrow-band sonar systems. The basilar membrane (BM) is coiled to 2.5 turns and about 12 mm long. Its thickness and width only change within the extreme basal and apical ends. The frequency range from about 30 to 80 kHz is represented in the lower basal turn with a typically mammalian mapping coefficient of about 3 mm/octave. This region exhibits morphological features correlated with non-specialized processing of high frequencies. (1) The BM is radially segmented by thickenings of pars tecta and pars pectinata. (2) The 3 rows of outer hair cells (OHCs) have similar morphology. Between 35 and 86% distance from base, frequencies between 30 and 12 kHz are represented with a slightly expanded mapping coefficient of about 6 mm/octave. In analogy to previous work, this cochlea region is termed acoustic fovea. It includes the frequency range of maximum sensitivity and sharpest tuning (21-27 kHz) but also frequencies below the sonar signals. The fovea is characterized by several morphological specializations. (1) The BM features a continuous radial thickening mainly composed of hyaline substance. (2) There is an increased number of layers of tension fibroblasts in the spiral ligament. (3) There are morphological differences in the arrangements of stereocilia bundles among the 3 rows of OHCs. The transitions between non-specialized and specialized cochlear regions occur gradually within a distance of about 600 microns. The gradients in stereocilia length of both receptor cell types and the gradations in length of the OHC bodies match specialized aspects of the frequency map. PMID:8647719

Vater, M; Siefer, W

1995-11-01

336

Accelerating Yeast Prion Biology using Droplet Microfluidics  

NASA Astrophysics Data System (ADS)

Prions are infectious proteins in a misfolded form, that can induce normal proteins to take the misfolded state. Yeast prions are relevant, as a model of human prion diseases, and interesting from an evolutionary standpoint. Prions may also be a form of epigenetic inheritance, which allow yeast to adapt to stressful conditions at rates exceeding those of random mutations and propagate that adaptation to their offspring. Encapsulation of yeast in droplet microfluidic devices enables high-throughput measurements with single cell resolution, which would not be feasible using bulk methods. Millions of populations of yeast can be screened to obtain reliable measurements of prion induction and loss rates. The population dynamics of clonal yeast, when a fraction of the cells are prion expressing, can be elucidated. Furthermore, the mechanism by which certain strains of bacteria induce yeast to express prions in the wild can be deduced. Integrating the disparate fields of prion biology and droplet microfluidics reveals a more complete picture of how prions may be more than just diseases and play a functional role in yeast.

Ung, Lloyd; Rotem, Assaf; Jarosz, Daniel; Datta, Manoshi; Lindquist, Susan; Weitz, David

2012-02-01

337

Extracellular Deoxyribonuclease Production by Yeasts  

PubMed Central

A total of 20 genera of yeasts and yeastlike organisms were tested for their ability to produce an extracellular deoxyribonuclease. Results indicate that ability to produce the enzyme appears to be a specific characteristic of the three genera Rhodotorula, Cryptococcus, and Tremella. A single strain of Endomycopsis fibuligera was also shown to be positive for the enzyme. In comparing the ability of the organisms to excrete extracellular deoxyribonuclease with their ability to produce urease, a surprisingly close correlation was found. With the exception of Lipomyces starkeyi, all the organisms which were deoxyribonuclease-negative were also urease-negative. Of those organisms which were deoxyribonuclease-positive, only E. fibuligera was urease-negative. The ability of cryptococci to produce extracellular deoxyribonuclease is discussed in relation to the implication which this finding may have for the taxonomy and phylogeny of the genus.

Cazin, John; Kozel, Thomas R.; Lupan, David M.; Burt, Wayne R.

1969-01-01

338

Extracellular deoxyribonuclease production by yeasts.  

PubMed

A total of 20 genera of yeasts and yeastlike organisms were tested for their ability to produce an extracellular deoxyribonuclease. Results indicate that ability to produce the enzyme appears to be a specific characteristic of the three genera Rhodotorula, Cryptococcus, and Tremella. A single strain of Endomycopsis fibuligera was also shown to be positive for the enzyme. In comparing the ability of the organisms to excrete extracellular deoxyribonuclease with their ability to produce urease, a surprisingly close correlation was found. With the exception of Lipomyces starkeyi, all the organisms which were deoxyribonuclease-negative were also urease-negative. Of those organisms which were deoxyribonuclease-positive, only E. fibuligera was urease-negative. The ability of cryptococci to produce extracellular deoxyribonuclease is discussed in relation to the implication which this finding may have for the taxonomy and phylogeny of the genus. PMID:5354946

Cazin, J; Kozel, T R; Lupan, D M; Burt, W R

1969-11-01

339

Rheologically interesting polysaccharides from yeasts  

NASA Technical Reports Server (NTRS)

We have examined the relationships between primary, secondary, and tertiary structures of polysaccharides exhibiting the rheological property of friction (drag) reduction in turbulent flows. We found an example of an exopolysaccharide from the yeast Cryptococcus laurentii that possessed high molecular weight but exhibited lower than expected drag reducing activity. Earlier correlations by Hoyt showing that beta 1 --> 3, beta 2 --> 4, and alpha 1 --> 3 linkages in polysaccharides favored drag reduction were expanded to include correlations to secondary structure. The effect of sidechains in a series of gellan gums was shown to be related to sidechain length and position. Disruption of secondary structure in drag reducing polysaccharides reduced drag reducing activity for some but not all exopolysaccharides. The polymer from C. laurentii was shown to be more stable than xanthan gum and other exopolysaccharides under the most vigorous of denaturing conditions. We also showed a direct relationship between extensional viscosity measurements and the drag reducing coefficient for four exopolysaccharides.

Petersen, G. R.; Nelson, G. A.; Cathey, C. A.; Fuller, G. G.

1989-01-01

340

Hydrogen Peroxide Metabolism in Yeasts  

PubMed Central

A catalase-negative mutant of the yeast Hansenula polymorpha consumed methanol in the presence of glucose when the organism was grown in carbon-limited chemostat cultures. The organism was apparently able to decompose the H2O2 generated in the oxidation of methanol by alcohol oxidase. Not only H2O2 generated intracellularly but also H2O2 added extracellularly was effectively destroyed by the catalase-negative mutant. From the rate of H2O2 consumption during growth in chemostat cultures on mixtures of glucose and H2O2, it appeared that the mutant was capable of decomposing H2O2 at a rate as high as 8 mmol · g of cells?1 · h?1. Glutathione peroxidase (EC 1.11.1.9) was absent under all growth conditions. However, cytochrome c peroxidase (CCP; EC 1.11.1.5) increased to very high levels in cells which decomposed H2O2. When wild-type H. polymorpha was grown on mixtures of glucose and methanol, the CCP level was independent of the rate of methanol utilization, whereas the level of catalase increased with increasing amounts of methanol in the substrate feed. Also, the wild type decomposed H2O2 at a high rate when cells were grown on mixtures of glucose and H2O2. In this case, an increase of both CCP and catalase was observed. When Saccharomyces cerevisiae was grown on mixtures of glucose and H2O2, the level of catalase remained low, but CCP increased with increasing rates of H2O2 utilization. From these observations and an analysis of cell yields under the various conditions, two conclusions can be drawn. (i) CCP is a key enzyme of H2O2 detoxification in yeasts. (ii) Catalase can effectively compete with mitochondrial CCP for hydrogen peroxide only if hydrogen peroxide is generated at the site where catalase is located, namely in the peroxisomes.

Verduyn, Cornelis; Giuseppin, Marco L. F.; Scheffers, W. Alexander; van Dijken, Johannes P.

1988-01-01

341

Pseudoporphyria associated with consumption of brewers' yeast.  

PubMed Central

A case of pseudoporphyria associated with excessive consumption of brewers ' yeast was studied. Detailed analysis of the yeast tablets by high performance liquid chromatography showed the presence of dicarboxylic deuteroporphyrin , mesoporphyrin, and protoporphyrin; coproporphyrin I and III isomers; and uroporphyrin I and III isomers. The faecal porphyrin concentration of the patient taking yeast tablets was significantly increased, resembling the excretion pattern in variegate porphyria. Any patient showing an unusual porphyrin excretion pattern on high performance liquid chromatography should be investigated for a possible dietary cause.

Lim, C K; Rideout, J M; Peters, T J

1984-01-01

342

Ethylene-Induced Increase in Glutamine Synthetase Activity and mRNA Levels in Hevea brasiliensis Latex Cells.  

PubMed Central

Ethylene, used as a stimulant of latex production in Hevea brasiliensis, significantly activates the regenerating metabolism within the laticiferous cells. In this context, attention was focused on glutamine synthetase (GS; EC 6.3.1.2), a key enzyme in nitrogen metabolism. A specific and significant activation of the cytosolic glutamine synthetase (GScyt) in the laticiferous cells after ethylene treatment parallels the increase of latex yield. A marked accumulation of the corresponding mRNA was found, but in contrast, a slight and variable increase of the polypeptide level is at the limit of detection by western blotting. The GS response to ethylene might be mediated by ammonia that increases in latex cytosol following ethylene treatment. The physiological significance for such a regulation by ethylene of the GScyt is discussed in terms of the nitrogen requirement for protein synthesis associated with latex regeneration.

Pujade-Renaud, V.; Clement, A.; Perrot-Rechenmann, C.; Prevot, J. C.; Chrestin, H.; Jacob, J. L.; Guern, J.

1994-01-01

343

Production of an antimicrobial substance against Cryptococcus neoformans by Paenibacillus brasilensis Sa3 isolated from the rhizosphere of Kalanchoe brasiliensis.  

PubMed

An antifungal substance produced by Paenibacillus brasilensis strain Sa3 was preliminary characterized and showed to be stable after treatment with different enzymes and organic solvents and at a wide range of pH, and presented a molecular weight between 3 and 10 kDa. In vitro antagonism of this strain towards Cryptococcus neoformans was investigated by optical and electronic microscopic analyses and a fungicidal effect on C. neoformans was observed. Ultrastructural analysis showed intense changes on the fungus when it was paired cultured with strain Sa3, mainly the detachment of the capsule from the cell wall and the presence of altered organelles in the cytoplasm. This novel antifungal substance produced by P. brasilensis Sa3 may represent a new insight in antifungal therapy mainly against emergent fungi. Also, prospective studies on rhizobacteria of plants as Kalanchoe brasiliensis may offer a potential source for the discovery of bioactive compounds with medical value. PMID:16790336

Fortes, Tiago Oliveira; Alviano, Daniela Sales; Tupinambá, Gleiser; Padrón, Thaís Souto; Antoniolli, Angelo Roberto; Alviano, Celuta Sales; Seldin, Lucy

2008-01-01

344

Marine killer yeasts active against a yeast strain pathogenic to crab Portunus trituberculatus.  

PubMed

Some marine yeasts have recently been recognised as pathogenic agents in crab mariculture, but may be inhibited or killed by 'killer' yeast strains. We screened multiple yeast strains from seawater, sediments, mud of salterns, guts of marine fish, and marine algae for killer activity against the yeast Metchnikowia bicuspidata WCY (pathogenic to crab Portunus trituberculatus), and found 17 strains which could secrete toxin onto the medium and kill the pathogenic yeast. Of these, 5 strains had significantly higher killing activity than the others; routine identification and molecular methods showed that these were Williopsis saturnus WC91-2, Pichia guilliermondii GZ1, Pichia anomala YF07b, Debaryomyces hansenii hcx-1 and Aureobasidium pullulans HN2.3. We found that the optimal conditions for killer toxin production and action of killer toxin produced by the marine killer yeasts were not all in agreement with those of marine environments and for crab cultivation. We found that the killer toxins produced by the killer yeast strains could kill other yeasts in addition to the pathogenic yeast, and NaCl concentration in the medium could change killing activity spectra. All the crude killer toxins produced could hydrolyze laminarin and the hydrolysis end products were monosaccharides. PMID:18814546

Wang, Lin; Yue, Lixi; Chi, Zhenming; Wang, Xianghong

2008-08-01

345

Predictive distribution modeling of the sandy-beach supralittoral amphipod Atlantorchestoidea brasiliensis along a macroscale estuarine gradient  

NASA Astrophysics Data System (ADS)

Exposed marine beaches are physically rigorous habitats in which macrofaunal patterns have been well correlated with physical factors. In this context, the habitat safety hypothesis (HSH) predicts an increase in abundance of supralittoral species from dissipative to reflective conditions in microtidal oceanic beaches. However, the HSH has not been adequately tested in estuarine sandy beaches. Here, we build a predictive model based on the supralittoral talitrid amphipod Atlantorchestoidea brasiliensis that allowed us to test the HSH along a macroscale estuarine gradient. Fifteen Uruguayan sandy beaches along a salinity gradient (from 0.1 to 34.3) generated by the Río de la Plata estuary (SW Atlantic Ocean) were sampled over a two-year period. A conditional two-step procedure using a General Additive Model (GAM) was performed in order to model A. brasiliensis occurrence (1st-step) and abundance (2nd-step), based on a comprehensive set of environmental variables [salinity, water temperature, beach face slope (BFS), mean grain size, wave height and sand compaction, moisture and organic matter]. Each GAM was parameterized using generalized linear models (GLMs). An external validation procedure was used. Data were divided randomly into training (75%) and test (25%) sets. The 1st-step GAM/GLM retained 5 physical descriptors in the model (decreasing order of importance): wave height, salinity, BFS, organic matter and sand compaction. The 2nd-step GAM/GLM retained 6 physical descriptors: sand compaction, water content, salinity, wave height, water temperature and organic matter. The predictive ability of these models and the resulted combined model, as well as their external validity, was highly significant and supported the predictions of the HSH. However, the highest and lowest abundances were observed, respectively, on reflective and dissipative beaches in the outer estuary; i.e., the predictions based on the HSH did not account for the high levels of abundance observed on these beaches compared with oceanic ones. Therefore, the HSH was expanded to include microtidal estuarine beaches.

Gómez, Julio; Defeo, Omar

2012-02-01

346

Proteome analysis of the large and the small rubber particles of Hevea brasiliensis using 2D-DIGE.  

PubMed

The rubber particle is a specialized organelle in which natural rubber is synthesised and stored in the laticifers of Hevea brasiliensis (para rubber tree). It has been demonstrated that the small rubber particles (SRPs) has higher rubber biosynthesis ratio than the large rubber particles (LRPs), but the underlying molecular mechanism still remains unknown. In this study, LRPs and SRPs were firstly separated from the fresh latex using differential centrifugation, and two-dimensional difference in-gel electrophoresis (2D-DIGE) combined with MALDI-TOF/TOF was then applied to investigate the proteomic alterations associated with the changed rubber biosynthesis capacity between LRPs and SRPs. A total of 53 spots corresponding to 22 gene products, were significantly altered with the |ratio|?2.0 and T value ?0.05, among which 15 proteins were up-regulated and 7 were down-regulated in the SRPs compared with the LRPs. The 15 up-regulated proteins in the SRPs included small rubber particle protein (SRPP), 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS), phospholipase D alpha (PLD ?), ethylene response factor 2, eukaryotic translation initiation factor 5A isoform IV (eIF 5A-4), 70-kDa heat shock cognate protein (HSC 70), several unknown proteins, etc., whereas the 7 up-regulated proteins in the LRPs were rubber elongation factor (REF, 19.6kDa), ASR-like protein 1, REF-like stress-related protein 1, a putative phosphoglyceride transfer family protein, ?-1,3-glucanase, a putative retroelement, and a hypothetical protein. Since several proteins related to rubber biosynthesis were differentially expressed between LRPs and SRPs, the comparative proteome data may provide useful insights into understanding the mechanism involved in rubber biosynthesis and latex coagulation in H. brasiliensis. PMID:22995218

Xiang, Qiulan; Xia, Kecan; Dai, Longjun; Kang, Guijuan; Li, Yu; Nie, Zhiyi; Duan, Cuifang; Zeng, Rizhong

2012-11-01

347

ENGINEERING THE BIOSYNTHESIS OF STYRENE IN YEAST  

EPA Science Inventory

The strategy pursued was to insert genes for phenylalanine ammonia lysase (pal) and phenolic acid decarboxylase (pad) into the yeast that would convert phenylalanine to styrene through a cinnamic acid intermediate. ...

348

Developmentally programmed nuclear destruction during yeast gametogenesis.  

PubMed

Autophagy controls cellular catabolism in diverse eukaryotes and modulates programmed cell death in plants and animals. While studies of the unicellular yeast Saccharomyces cerevisiae have provided fundamental insights into the mechanisms of autophagy, the roles of cell death pathways in yeast are less well understood. Here, we describe widespread developmentally programmed nuclear destruction (PND) events that occur during yeast gametogenesis. PND is executed through apoptotic-like DNA fragmentation in coordination with an unusual form of autophagy that is most similar to mammalian lysosomal membrane permeabilization and mega-autophagy, a form of plant autophagic cell death. Undomesticated strains execute gametogenic PND broadly in maturing colonies to the apparent benefit of sibling cells, confirming its prominence during the yeast life cycle. Our results reveal that diverse cell-death-related processes converge during gametogenesis in a microbe distantly related to plants or animals, highlighting gametogenesis as a process during which programmed cell death mechanisms may have evolved. PMID:22727375

Eastwood, Michael D; Cheung, Sally W T; Lee, Kwan Yin; Moffat, Jason; Meneghini, Marc D

2012-07-17

349

Yeast survive by hedging their bets.  

PubMed

A new experimental approach reveals a bet hedging strategy in unstressed, clonal yeast cells, whereby they adopt a range of growth states that correlate with expression of a trehalose-synthesis regulator and predict resistance to future stress. PMID:22589702

Meadows, Robin

2012-01-01

350

Protection from nitrosative stress by yeast flavohemoglobin  

PubMed Central

Yeast hemoglobin was discovered close to half a century ago, but its function has remained unknown. Herein, we report that this flavohemoglobin protects Saccharomyces cerevisiae from nitrosative stress. Deletion of the flavohemoglobin gene (YHB1) abolished the nitric oxide (NO)-consuming activity of yeast cells. Levels of protein nitrosylation were more than 10-fold higher in yhb1 mutant yeast than in isogenic wild-type cells after incubation with NO donors. Growth of mutant cells was inhibited by a nitrosative challenge that had little effect on wild-type cells, whereas the resistance of mutant cells to oxidative stress was unimpaired. Protection conferred by yeast flavohemoglobin against NO and S-nitrosothiols was seen under both anaerobic and aerobic conditions, consistent with a primary function in NO detoxification. A phylogenetic analysis indicated that protection from nitrosative stress is likely to be a conserved function among microorganismal flavohemoglobins. Flavohemoglobin is therefore a potential target for antimicrobial therapy.

Liu, Limin; Zeng, Ming; Hausladen, Alfred; Heitman, Joseph; Stamler, Jonathan S.

2000-01-01

351

Production of biopharmaceutical proteins by yeast  

PubMed Central

Production of recombinant proteins for use as pharmaceuticals, so-called biopharmaceuticals, is a multi-billion dollar industry. Many different cell factories are used for the production of biopharmaceuticals, but the yeast Saccharomyces cerevisiae is an important cell factory as it is used for production of several large volume products. Insulin and insulin analogs are by far the dominating biopharmaceuticals produced by yeast, and this will increase as the global insulin market is expected to grow from USD12B in 2011 to more than USD32B by 2018. Other important biopharmaceuticals produced by yeast are human serum albumin, hepatitis vaccines and virus like particles used for vaccination against human papillomavirus. Here is given a brief overview of biopharmaceutical production by yeast and it is discussed how the secretory pathway can be engineered to ensure more efficient protein production. The involvement of directed metabolic engineering through the integration of tools from genetic engineering, systems biology and mathematical modeling, is also discussed.

Nielsen, Jens

2013-01-01

352

Arachidonic acid metabolites in pathogenic yeasts  

PubMed Central

Although most of what is known about the biology and function of arachidonic acid metabolites comes from the study of mammalian biology, these compounds can also be produced by lower eukaryotes, including yeasts and other fungi. It is also in this group of organisms that the least is known about the metabolic pathways leading to the production of these compounds as well as the functions of these compounds in the biology of fungi and yeasts. This review will deal with the discovery of oxylipins from polyunsaturated fatty acids, and more specifically the arachidonic acid derived eicosanoids, such as 3-hydroxy eicosatetraenoic acid, prostaglandin F2? and prostaglandin E2, in yeasts starting in the early 1990s. This review will also focus on what is known about the metabolic pathways and/or proteins involved in the production of these compounds in pathogenic yeasts. The possible roles of these compounds in the biology, including the pathology, of these organisms will be discussed.

2012-01-01

353

Yeast Screens for Treatment of Human Disease.  

National Technical Information Service (NTIS)

Screening methods for identifying substances that provide therapeutic value for various diseases associated with protein misfolding are provided. Genetic and chemical screening methods are provided using a yeast system. The methods of the invention provid...

S. Krobitsch S. Lindquist T. F. Outeiro

2006-01-01

354

Carbon source dependent promoters in yeasts  

PubMed Central

Budding yeasts are important expression hosts for the production of recombinant proteins. The choice of the right promoter is a crucial point for efficient gene expression, as most regulations take place at the transcriptional level. A wide and constantly increasing range of inducible, derepressed and constitutive promoters have been applied for gene expression in yeasts in the past; their different behaviours were a reflection of the different needs of individual processes. Within this review we summarize the majority of the large available set of carbon source dependent promoters for protein expression in yeasts, either induced or derepressed by the particular carbon source provided. We examined the most common derepressed promoters for Saccharomyces cerevisiae and other yeasts, and described carbon source inducible promoters and promoters induced by non-sugar carbon sources. A special focus is given to promoters that are activated as soon as glucose is depleted, since such promoters can be very effective and offer an uncomplicated and scalable cultivation procedure.

2014-01-01

355

Identification of Protein Components of Yeast Telomerase.  

National Technical Information Service (NTIS)

Telomere length is tightly regulated in Saccharomycetes. This lengthening is dependent on TLC1, which encodes the RNA component of telomerase but independent of RAD52, which encodes a protein required for most recombination events in mitotic yeast cells. ...

S. Teng

1999-01-01

356

Monitoring Air Quality with Leaf Yeasts.  

ERIC Educational Resources Information Center

Proposes that leaf yeast serve as quick, inexpensive, and effective techniques for monitoring air quality. Outlines procedures and provides suggestions for data analysis. Includes results from sample school groups who employed this technique. (ML)

Richardson, D. H. S.; And Others

1985-01-01

357

Intracellular production of recombinant serpins in yeast.  

PubMed

Yeast are a valuable system for recombinant serpin production due to their ability to synthesize large amounts of heterologous gene products as well as their expression of folding chaperones and lack of endogenous serpin genes. In this chapter, we describe a method for intracellular expression of cytoplasmic serpins in the yeast Pichia pastoris. We also give details on how this system can be exploited to produce polymer-forming mutants of secretory serpins. PMID:22078527

Kaiserman, Dion; Hitchen, Corinne; Levina, Vita; Bottomley, Stephen P; Bird, Phillip I

2011-01-01

358

Yeast Killer Toxins: Fundamentals and Applications  

Microsoft Academic Search

\\u000a Killer phenomena in yeast are due to the secretion of polypeptides with a lethal or growth-inhibitory effect on competing\\u000a strains. Yeast killer toxins display structural heterogeneity, ranging in size from small peptides to large protein complexes.\\u000a Accordingly, they attack various constituents of sensitive cells, including the cell wall and plasma membrane, but also intracellular\\u000a targets such as the replication machinery

Friedhelm Meinhardt; Roland Klassen

359

How To Make Yeast Cells Thrive  

NSDL National Science Digital Library

Students set up and run the experiments they designed in the lesson Population Growth in Yeasts, using simple yeast-molasses cultures in test tubes. Population growth is indicated by the amount of respiration occurring in the cultures, which in turn is indicated by the growth of carbon dioxide bubbles trapped within the culture tubes. Using this method, students can test for a variety of environmental influences, such as temperature, food supply, and pH.

Engineering K-Ph.d. Program

360

Analysis of recombinant yeast decapping enzyme  

Microsoft Academic Search

A critical step in the turnover of yeast mRNAs is decapping. Two yeast proteins, Dcp1p and Dcp2p, are absolutely required for decapping, although their precise roles in the decapping reaction have not been established. To determine the function of both Dcp1p and Dcp2p in decapping, we purified recombinant versions of these proteins from Escherichia coli and examined their properties. These

MICHELLE STEIGER; ANNE CARR-SCHMID; DAVID C. SCHWARTZ; MEGERDITCH KILEDJIAN; ROY PARKER

2003-01-01

361

Phylogenetics of Saccharomycetales, the ascomycete yeasts.  

PubMed

Ascomycete yeasts (phylum Ascomycota: subphylum Saccharomycotina: class Saccharomycetes: order Saccharomycetales) comprise a monophyletic lineage with a single order of about 1000 known species. These yeasts live as saprobes, often in association with plants, animals and their interfaces. A few species account for most human mycotic infections, and fewer than 10 species are plant pathogens. Yeasts are responsible for important industrial and biotechnological processes, including baking, brewing and synthesis of recombinant proteins. Species such as Saccharomyces cerevisiae are model organisms in research, some of which led to a Nobel Prize. Yeasts usually reproduce asexually by budding, and their sexual states are not enclosed in a fruiting body. The group also is well defined by synapomorphies visible at the ultrastructural level. Yeast identification and classification changed dramatically with the availability of DNA sequencing. Species identification now benefits from a constantly updated sequence database and no longer relies on ambiguous growth tests. A phylogeny based on single gene analyses has shown the order to be remarkably divergent despite morphological similarities among members. The limits of many previously described genera are not supported by sequence comparisons, and multigene phylogenetic studies are under way to provide a stable circumscription of genera, families and orders. One recent multigene study has resolved species of the Saccharomycetaceae into genera that differ markedly from those defined by analysis of morphology and growth responses, and similar changes are likely to occur in other branches of the yeast tree as additional sequences become available. PMID:17486976

Suh, Sung-Oui; Blackwell, Meredith; Kurtzman, Cletus P; Lachance, Marc-André

2006-01-01

362

Yeast as a model for Ras signalling.  

PubMed

For centuries yeast species have been popular hosts for classical biotechnology processes, such as baking, brewing, and wine making, and more recently for recombinant proteins production, thanks to the advantages of unicellular organisms (i.e., ease of genetic manipulation and rapid growth) together with the ability to perform eukaryotic posttranslational modifications. Moreover, yeast cells have been used for few decades as a tool for identifying the genes and pathways involved in basic cellular processes such as the cell cycle, aging, and stress response. In the budding yeast S. cerevisiae the Ras/cAMP/PKA pathway is directly involved in the regulation of metabolism, cell growth, stress resistance, and proliferation in response to the availability of nutrients and in the adaptation to glucose, controlling cytosolic cAMP levels and consequently the cAMP-dependent protein kinase (PKA) activity. Moreover, Ras signalling has been identified in several pathogenic yeasts as a key controller for virulence, due to its involvement in yeast morphogenesis. Nowadays, yeasts are still useful for Ras-like proteins investigation, both as model organisms and as a test tube to study variants of heterologous Ras-like proteins. PMID:24470037

Tisi, Renata; Belotti, Fiorella; Martegani, Enzo

2014-01-01

363

Yeast communities in a natural tequila fermentation.  

PubMed

Fresh and cooked agave, Drosophila spp., processing equipment, agave molasses, agave extract, and fermenting must at a traditional tequila distillery (Herradura, Amatitan, Jalisco, México) were studied to gain insight on the origin of yeasts involved in a natural tequila fermentations. Five yeast communities were identified. (1) Fresh agave contained a diverse mycobiota dominated by Clavispora lusitaniae and an endemic species, Metschnikowia agaveae. (2) Drosophila spp. from around or inside the distillery yielded typical fruit yeasts, in particular Hanseniaspora spp., Pichia kluyveri, and Candida krusei. (3) Schizosaccharomyces pombe prevailed in molasses. (4) Cooked agave and extract had a considerable diversity of species, but included Saccharomyces cerevisiae. (5) Fermenting juice underwent a gradual reduction in yeast heterogeneity. Torulaspora delbrueckii, Kluyveromyces marxianus, and Hanseniaspora spp. progressively ceded the way to S. cerevisiae, Zygosaccharomyces bailii, Candida milleri, and Brettanomyces spp. With the exception of Pichia membranaefaciens, which was shared by all communities, little overlap existed. That separation was even more manifest when species were divided into distinguishable biotypes based on morphology or physiology. It is concluded that crushing equipment and must holding tanks are the main source of significant inoculum for the fermentation process. Drosophila species appear to serve as internal vectors. Proximity to fruit trees probably contributes to maintaining a substantial Drosophila community, but the yeasts found in the distillery exhibit very little similarity to those found in adjacent vegetation. Interactions involving killer toxins had no apparent direct effects on the yeast community structure. PMID:8546452

Lachance, M A

1995-08-01

364

Interactions between yeast TFIIIB components.  

PubMed Central

Yeast transcription factor TFIIIB is a multicomponent factor comprised of the TATA-binding protein TBP and of associated factors TFIIIB70 and B". Epitope-tagged or histidine-tagged TFIIIB70 could be quantitatively removed from TFIIIB by affinity chromatography. TBP and B" (apparent mass 160-200 kDa) could be easily separated by gel filtration or ion-exchange chromatography. While only weak interactions were detected between TBP and B", direct binding of [35S]-labeled TBP to membrane-bound TFIIIB70 could be demonstrated in absence of DNA. On tRNA genes, there was no basal level of transcription in the complete absence of TBP. The two characterized TFIIIB components (recombinant rTFIIIB70 and rTBP) and a fraction cochromatographing with B" activity were found to be required for TFIIIC-independent transcription of the TATA-containing U6 RNA gene in vitro. Therefore, beside the TFIIIC-dependent assembly process, each TFIIIB component must have an essential role in DNA binding or RNA polymerase recruitment. Images

Huet, J; Conesa, C; Manaud, N; Chaussivert, N; Sentenac, A

1994-01-01

365

Yeast prions assembly and propagation  

PubMed Central

Yeast prions are self-perpetuating protein aggregates that are at the origin of heritable and transmissible non-Mendelian phenotypic traits. Among these, [PSI+], [URE3] and [PIN+] are the most well documented prions and arise from the assembly of Sup35p, Ure2p and Rnq1p, respectively, into insoluble fibrillar assemblies. Fibril assembly depends on the presence of N- or C-terminal prion domains (PrDs) which are not homologous in sequence but share unusual amino-acid compositions, such as enrichment in polar residues (glutamines and asparagines) or the presence of oligopeptide repeats. Purified PrDs form amyloid fibrils that can convert prion-free cells to the prion state upon transformation. Nonetheless, isolated PrDs and full-length prion proteins have different aggregation, structural and infectious properties. In addition, mutations in the “non-prion” domains (non-PrDs) of Sup35p, Ure2p and Rnq1p were shown to affect their prion properties in vitro and in vivo. Despite these evidences, the implication of the functional non-PrDs in fibril assembly and prion propagation has been mostly overlooked. In this review, we discuss the contribution of non-PrDs to prion assemblies, and the structure-function relationship in prion infectivity in the light of recent findings on Sup35p and Ure2p assembly into infectious fibrils from our laboratory and others.

2011-01-01

366

Glycogenolytic enzymes in sporulating yeast.  

PubMed Central

During meiosis in Saccharomyces cerevisiae, the polysaccharide glycogen is first synthesized and then degraded during the period of spore maturation. We have detected, in sporulating yeast strains, an enzyme activity which is responsible for the glycogen catabolism. The activity was absent in vegetative cells, appeared coincidently with the beginning of glycogenolysis and the appearance of mature ascospores, and increased progressively until spourlation was complete. The specific activity of glycogenolytic enzymes in the intact ascus was about threefold higher than in isolated spores. The glycogenolysis was not due to combinations of phosphorylase plus phosphatase or amylase plus maltase. Nonsporulating cells exhibited litle or no glycogen catabolism and contained only traces of glycogenolytic enzyme, suggesting that the activity is sporulation specific. The partially purified enzyme preparation degraded amylose and glycogen, releasing glucose as the only low-molecular-weight product. Maltotriose was rapidly hydrolyzed; maltose was less susceptible. Alpha-methyl-D-glucoside, isomaltose, and linear alpha-1,6-linked dextran were not attacked. However, the enzyme hydrolyzed alpha-1,6-glucosyl-Schardinger dextrin and increased the beta-amylolysis of beta-amylase-limit dextrin. Thus, the preparation contains alpha-1,4- and alpha-1,6-glucosidase activities. Sephadex G-150 chromatography partially resolved the enzyme into two activities, one of which may be a glucamylase and the other a debranching enzyme. Images

Colonna, W J; Magee, P T

1978-01-01

367

The One Hour Yeast Proteome*  

PubMed Central

We describe the comprehensive analysis of the yeast proteome in just over one hour of optimized analysis. We achieve this expedited proteome characterization with improved sample preparation, chromatographic separations, and by using a new Orbitrap hybrid mass spectrometer equipped with a mass filter, a collision cell, a high-field Orbitrap analyzer, and, finally, a dual cell linear ion trap analyzer (Q-OT-qIT, Orbitrap Fusion). This system offers high MS2 acquisition speed of 20 Hz and detects up to 19 peptide sequences within a single second of operation. Over a 1.3 h chromatographic method, the Q-OT-qIT hybrid collected an average of 13,447 MS1 and 80,460 MS2 scans (per run) to produce 43,400 (x?) peptide spectral matches and 34,255 (x?) peptides with unique amino acid sequences (1% false discovery rate (FDR)). On average, each one hour analysis achieved detection of 3,977 proteins (1% FDR). We conclude that further improvements in mass spectrometer scan rate could render comprehensive analysis of the human proteome within a few hours.

Hebert, Alexander S.; Richards, Alicia L.; Bailey, Derek J.; Ulbrich, Arne; Coughlin, Emma E.; Westphall, Michael S.; Coon, Joshua J.

2014-01-01

368

Yeast and human mitochondrial helicases.  

PubMed

Mitochondria are semiautonomous organelles which contain their own genome. Both maintenance and expression of mitochondrial DNA require activity of RNA and DNA helicases. In Saccharomyces cerevisiae the nuclear genome encodes four DExH/D superfamily members (MSS116, SUV3, MRH4, IRC3) that act as helicases and/or RNA chaperones. Their activity is necessary for mitochondrial RNA splicing, degradation, translation and genome maintenance. In humans the ortholog of SUV3 (hSUV3, SUPV3L1) so far is the best described mitochondrial RNA helicase. The enzyme, together with the matrix-localized pool of PNPase (PNPT1), forms an RNA-degrading complex called the mitochondrial degradosome, which localizes to distinct structures (D-foci). Global regulation of mitochondrially encoded genes can be achieved by changing mitochondrial DNA copy number. This way the proteins involved in its replication, like the Twinkle helicase (c10orf2), can indirectly regulate gene expression. Here, we describe yeast and human mitochondrial helicases that are directly involved in mitochondrial RNA metabolism, and present other helicases that participate in mitochondrial DNA replication and maintenance. This article is part of a Special Issue entitled: The Biology of RNA helicases - Modulation for life. PMID:23454114

Szczesny, Roman J; Wojcik, Magdalena A; Borowski, Lukasz S; Szewczyk, Maciej J; Skrok, Magda M; Golik, Pawel; Stepien, Piotr P

2013-08-01

369

Inhibition of spoilage yeasts in cheese by killer yeast Williopsis saturnus var. saturnus.  

PubMed

Williopsis saturnus var. saturnus is a known killer toxin-producing yeast. The effects of this yeast as a biopreservative against spoilage yeasts (galactose fermenting) were investigated in cheeses made under laboratory conditions. At an inoculation level of approximately 10(6) CFU/g of cheese, this killer yeast inhibited growth of lactose non-fermenting but galactose-fermenting yeast Saccharomyces cerevisiae VL1 inoculated at approximately 10(3) CFU/g; it also inhibited growth of lactose-fermenting and galactose-fermenting yeast Kluvyveromyces marxianus ATCC8640 inoculated at approximately 10(3)-10(4) CFU/g in the cheeses manufactured with galactose-producing starter culture Streptococcus thermophilus. In contrast, the two spoilage yeasts grew to approximately 10(6) CFU/g from the initial cell count of approximately 10(3) CFU/g without the killer yeast. This study indicated that W. saturnus var. saturnus could be an effective biopreservative for cheese spoilage control. PMID:19349088

Liu, Shao-Quan; Tsao, Marlene

2009-05-31

370

Boolean Model of Yeast Apoptosis as a Tool to Study Yeast and Human Apoptotic Regulations  

PubMed Central

Programmed cell death (PCD) is an essential cellular mechanism that is evolutionary conserved, mediated through various pathways and acts by integrating different stimuli. Many diseases such as neurodegenerative diseases and cancers are found to be caused by, or associated with, regulations in the cell death pathways. Yeast Saccharomyces cerevisiae, is a unicellular eukaryotic organism that shares with human cells components and pathways of the PCD and is therefore used as a model organism. Boolean modeling is becoming promising approach to capture qualitative behavior and describe essential properties of such complex networks. Here we present large literature-based and to our knowledge first Boolean model that combines pathways leading to apoptosis (a type of PCD) in yeast. Analysis of the yeast model confirmed experimental findings of anti-apoptotic role of Bir1p and pro-apoptotic role of Stm1p and revealed activation of the stress protein kinase Hog proposing the maximal level of activation upon heat stress. In addition we extended the yeast model and created an in silico humanized yeast in which human pro- and anti-apoptotic regulators Bcl-2 family and Valosin-contain protein (VCP) are included in the model. We showed that accumulation of Bax in silico humanized yeast shows apoptotic markers and that VCP is essential target of Akt Signaling. The presented Boolean model provides comprehensive description of yeast apoptosis network behavior. Extended model of humanized yeast gives new insights of how complex human disease like neurodegeneration can initially be tested.

Kazemzadeh, Laleh; Cvijovic, Marija; Petranovic, Dina

2012-01-01

371

Vacuolar-type inorganic pyrophosphatase located on the rubber particle in the latex is an essential enzyme in regulation of the rubber biosynthesis in Hevea brasiliensis  

Microsoft Academic Search

V-PPase is found in most plants, some parasitic protists, eubacteria and archaebacteria, and performs crucial functions through the hydrolysis of PPi released from various metabolic pathways. In this study, one V-PPase gene (Hbvp1) and its promoter were cloned from the rubber tree (Hevea brasiliensis). The length of Hbvp1 cDNA is 2798bp and it encodes a protein of 769 amino acids.

Zeng Rizhong; Duan Cuifang; Li Xiaoyuan; Tian Weimin; Nie Zhiyi

2009-01-01

372

Chemical composition and larvicidal properties of the essential oils from Drimys brasiliensis Miers (Winteraceae) on the cattle tick Rhipicephalus ( Boophilus ) microplus and the brown dog tick Rhipicephalus sanguineus  

Microsoft Academic Search

The essential oil obtained from leaves and stem barks of the Southern Brazilian native Drimys brasiliensis Miers, a tree with medicinal properties, was analyzed by gas chromatography (GC) and GC\\/mass spectrometry (MS). The oil was\\u000a characterized by sesquiterpenoids (66%), cyclocolorenone being the most abundant (30.4%), followed by bicyclogermacrene (11.8%)\\u000a and alpha-gurjunene (6.0%). Laboratory tests were carried out to determine the

Vera Lúcia Sardá Ribeiro; Verônica Rolim; Sérgio Bordignon; Amélia T. Henriques; Gilséia G. Dorneles; Renata P. Limberger; Gilsane von Poser

2008-01-01

373

Morphology and phylogenetic position of a trebouxiophycean green alga (Chlorophyta) growing on the rubber tree, Hevea brasiliensis, with the description of a new genus and species  

Microsoft Academic Search

A novel unicellular Chlorella-like green alga was isolated from the rubber tree (Hevea brasiliensis). The cultured cells were described by light and electron microscopy. Most adult cells were spherical with a single cup-shaped parietal chloroplast, although a few cells contained 2 to 4 chloroplasts. Chloroplasts contained many small pyrenoids with pyrenoglobuli around the multi-oriented tube-like thylakoids in the pyrenoid matrix.

Jiaming Zhang; Volker A. R. Huss; Xuepiao Sun; Kaijun Chang; Daobiao Pang

2008-01-01

374

Cutaneous manifestations of Nocardia brasiliensis infection in Taiwan during 2002-2012-clinical studies and molecular typing of pathogen by gyrB and 16S gene sequencing.  

PubMed

To observe the clinicopathologic and resistance profiles of the Nocardia brasiliensis causing cutaneous nocardiosis in Taiwan, 12 N. brasiliensis isolates were prospectively collected from patients with cutaneous nocardiosis in a hospital during 2002-2012. Clinicopathologic data were obtained, and isolates were identified by biochemical methods and 16S rRNA sequencing. Susceptibilities to 14 antimicrobial compounds were tested. Isolates were further genotyped by sequencing of 16S rRNA, secA1, hsp65, and gyrB genes. The nodulopustular pyoderma associated with sporotrichoid spreading was the most common skin presentations caused by N. brasiliensis. All of the isolates were susceptible to amikacin, gentamicin, tobramycin, piperacillin/tazobactam, and trimethoprim/sulfamethoxazole and resistant to kanamycin, erythromycin, and oxacillin, while susceptibilities to imipenem, vancomycin, penicillin-G, tetracycline, clindamycin, and ciprofloxacin varied among the 12 isolates. GyrB genotyping delineated the 12 isolates into 2 major groups, which was coincident with different single nucleotide substitutions at position 160 (G versus T) of 16S rRNA, different levels of imipenem minimum inhibition concentration (4-32 versus 0.25-0.75 mg/L), and prevalence of lymphadenitis (66.7 versus 16.7%). We have noted that tiny pustular lesions can be the first sign of cutaneous nocardiosis, which we believe has not been previously emphasized. No resistance to trimethoprim and sulfamethoxazole was found; therefore, sulphonamide drugs remain effective for treatment of cutaneous nocardiosis in Taiwan. PMID:23791388

Chen, Kuo-Wei; Lu, Chun-Wei; Huang, Ting-Chi; Lu, Chin-Fang; Liau, Yea-Ling; Lin, Jeng-Fong; Li, Shu-Ying

2013-09-01

375

Modeling diauxic glycolytic oscillations in yeast.  

PubMed

Glycolytic oscillations in a stirred suspension of starved yeast cells is an excellent model system for studying the dynamics of metabolic switching in living systems. In an open-flow system the oscillations can be maintained indefinitely at a constant operating point where they can be characterized quantitatively by experimental quenching and bifurcation analysis. In this article, we use these methods to show that the dynamics of oscillations in a closed system is a simple transient version of the open-system dynamics. Thus, easy-setup closed-system experiments are also useful for investigations of central metabolism dynamics of yeast cells. We have previously proposed a model for the open system comprised of the primary fermentative reactions in yeast that quantitatively describes the oscillatory dynamics. However, this model fails to describe the transient behavior of metabolic switching in a closed-system experiment by feeding the yeast suspension with a glucose pulse-notably the initial NADH spike and final NADH rise. Another object of this study is to gain insight into the secondary low-flux metabolic pathways by feeding starved yeast cells with various metabolites. Experimental and computational results strongly suggest that regulation of acetaldehyde explains the observed behavior. We have extended the original model with regulation of pyruvate decarboxylase, a reversible alcohol dehydrogenase, and drainage of pyruvate. Using the method of time rescaling in the extended model, the description of the transient closed-system experiments is significantly improved. PMID:21081066

Hald, Bjørn Olav; Sørensen, Preben G

2010-11-17

376

Ecology of pathogenic yeasts in Amazonian soil.  

PubMed Central

In an investigation of Amazonian soil as a natural reservoir for pathogenic fungi, 1,949 soil samples collected from diverse geographical and ecological settings of the Brazilian Amazon Basin were analyzed for the presence of non-keratinophilic fungi by the indirect mouse inoculation procedure and for the presence of keratinophilic fungi by the hair bait technique. All soil samples were acidic with low pH values. From 12% of the soil samples, 241 yeast and yeastlike isolates pertaining to six genera and 82 species were recovered, of which 63% were Torulopsis and 26% were Candida species. Nine fungi with known pathogenic potentials were encountered among 43% (104) of the isolates: T. glabrata, C. guilliermondii, C. albicans, C. pseudotropicalis, C. stellatoidea, C. tropicalis, Rhodotorula rubra, and Wangiella dermatitidis. The yeast flora was marked by species diversity, low frequency of each species, random geographical distribution, and an apparent lack of species clustering. The composition and distribution of the yeast flora in soil differed from those of the yeast flora harbored by bats, suggesting that the Amazonian external environment and internal bat organs act as independent natural habitats for yeasts.

Mok, W Y; Luizao, R C; do Socorro Barreto da Silva, M; Teixeira, M F; Muniz, E G

1984-01-01

377

Influence of pesticides on yeasts colonizing leaves.  

PubMed

The effect of nine different pesticides on the growth of yeasts isolated from the leaves of fruit and forest trees was investigated. Four insecticides (with the active ingredients: thiacloprid, deltamethrin, lambdacyhalothrin, and thiamethoxam) and five fungicides (with the effective substances: bitertanol, kresoxim-methyl, mancozeb, trifloxystrobin, and cupric oxychloride) were tested. The concentrations of chemicals were those recommended by the manufacturers for the spraying of trees. The yeast strains isolated from the leaves of fruit trees were not sensitive to any of the insecticides. The majority of yeast strains isolated from the leaves of forest trees were either not sensitive or only to a small extent. While Rhodotorula mucilaginosa and Pichia anomala were not affected by any insecticide, the strains of Cryptococcus laurentii and Rhodotorula glutinis showed the highest sensitivity. The effects of fungicides on the growth of isolated yeasts were more substantial. The fungicide Dithane DG (mancozeb) completely inhibited the growth of all yeasts. All strains isolated from fruit tree leaves were more resistant to the tested fungicides than those isolated from the leaves of forest trees. The most resistant strains from the leaves of fruit trees belonged to the species Metschnikowia pulcherrima, Pichia anomala, and Saccharomyces cerevisiae, whereas Cryptococcus albidus and C. laurentii, originating from the leaves of forest trees, showed the highest sensitivity to fungicides. PMID:22351984

Vadkertiová, Renata; Sláviková, Elena

2011-01-01

378

Simple assay of trehalose in industrial yeast.  

PubMed

Trehalose is an essential chemical marker to control a quality of the industrial yeast strains and to assess a tolerance of the yeasts products to different physical stresses. A high-performance liquid chromatography analysis with charged aerosol detection (HPLC-CAD) was developed for trehalose determination in industrial yeasts. The method offers a linearity in the range of 5.0-15 mM with linear regression coefficient R(2)=0.9995, a good reproducibility and relatively short analysis time (7 min). Trehalose can be detected at concentrations as low as 0.07 mM, and limit of precise quantification is 0.2 mM. The coefficient of variation (CV%) is 0.3%. The developed method is more sensitive compared with conventional chromatography procedure with UV absorbance detection. It was shown that the proposed method can be used in baker's industry to control a quality of the yeast products and to assess biotechnological significance of the yeast strains. PMID:24731351

Kus-Li?kiewicz, Ma?gorzata; Górka, Anna; Gonchar, Mykhailo

2014-09-01

379

Modeling Diauxic Glycolytic Oscillations in Yeast  

PubMed Central

Glycolytic oscillations in a stirred suspension of starved yeast cells is an excellent model system for studying the dynamics of metabolic switching in living systems. In an open-flow system the oscillations can be maintained indefinitely at a constant operating point where they can be characterized quantitatively by experimental quenching and bifurcation analysis. In this article, we use these methods to show that the dynamics of oscillations in a closed system is a simple transient version of the open-system dynamics. Thus, easy-setup closed-system experiments are also useful for investigations of central metabolism dynamics of yeast cells. We have previously proposed a model for the open system comprised of the primary fermentative reactions in yeast that quantitatively describes the oscillatory dynamics. However, this model fails to describe the transient behavior of metabolic switching in a closed-system experiment by feeding the yeast suspension with a glucose pulse—notably the initial NADH spike and final NADH rise. Another object of this study is to gain insight into the secondary low-flux metabolic pathways by feeding starved yeast cells with various metabolites. Experimental and computational results strongly suggest that regulation of acetaldehyde explains the observed behavior. We have extended the original model with regulation of pyruvate decarboxylase, a reversible alcohol dehydrogenase, and drainage of pyruvate. Using the method of time rescaling in the extended model, the description of the transient closed-system experiments is significantly improved.

Hald, Bj?rn Olav; S?rensen, Preben G.

2010-01-01

380

Mitochondrial membrane lipidome defines yeast longevity  

PubMed Central

Our studies revealed that lithocholic acid (LCA), a bile acid, is a potent anti-aging natural compound that in yeast cultured under longevity-extending caloric restriction (CR) conditions acts in synergy with CR to enable a significant further increase in chronological lifespan. Here, we investigate a mechanism underlying this robust longevity-extending effect of LCA under CR. We found that exogenously added LCA enters yeast cells, is sorted to mitochondria, resides mainly in the inner mitochondrial membrane, and also associates with the outer mitochondrial membrane. LCA elicits an age-related remodeling of glycerophospholipid synthesis and movement within both mitochondrial membranes, thereby causing substantial changes in mitochondrial membrane lipidome and triggering major changes in mitochondrial size, number and morphology. In synergy, these changes in the membrane lipidome and morphology of mitochondria alter the age-related chronology of mitochondrial respiration, membrane potential, ATP synthesis and reactive oxygen species homeostasis. The LCA-driven alterations in the age-related dynamics of these vital mitochondrial processes extend yeast longevity. In sum, our findings suggest a mechanism underlying the ability of LCA to delay chronological aging in yeast by accumulating in both mitochondrial membranes and altering their glycerophospholipid compositions. We concluded that mitochondrial membrane lipidome plays an essential role in defining yeast longevity.

Burstein, Michelle T.; Bourque, Simon D.; Koupaki, Olivia; Juneau, Mylene; Feldman, Rachel; Iouk, Tatiana; Titorenko, Vladimir I.

2013-01-01

381

Extension of Yeast Chronological Lifespan by Methylamine  

PubMed Central

Background Chronological aging of yeast cells is commonly used as a model for aging of human post-mitotic cells. The yeast Saccharomyces cerevisiae grown on glucose in the presence of ammonium sulphate is mainly used in yeast aging research. We have analyzed chronological aging of the yeast Hansenula polymorpha grown at conditions that require primary peroxisome metabolism for growth. Methodology/Principal Findings The chronological lifespan of H. polymorpha is strongly enhanced when cells are grown on methanol or ethanol, metabolized by peroxisome enzymes, relative to growth on glucose that does not require peroxisomes. The short lifespan of H. polymorpha on glucose is mainly due to medium acidification, whereas most likely ROS do not play an important role. Growth of cells on methanol/methylamine instead of methanol/ammonium sulphate resulted in further lifespan enhancement. This was unrelated to medium acidification. We show that oxidation of methylamine by peroxisomal amine oxidase at carbon starvation conditions is responsible for lifespan extension. The methylamine oxidation product formaldehyde is further oxidized resulting in NADH generation, which contributes to increased ATP generation and reduction of ROS levels in the stationary phase. Conclusion/Significance We conclude that primary peroxisome metabolism enhanced chronological lifespan of H. polymorpha. Moreover, the possibility to generate NADH at carbon starvation conditions by an organic nitrogen source supports further extension of the lifespan of the cell. Consequently, the interpretation of CLS analyses in yeast should include possible effects on the energy status of the cell.

Kumar, Sanjeev; Lefevre, Sophie D.; Veenhuis, Marten; van der Klei, Ida J.

2012-01-01

382

Yeasts and yeast-like organisms associated with fruits and blossoms of different fruit trees.  

PubMed

Yeasts are common inhabitants of the phyllosphere, but our knowledge of their diversity in various plant organs is still limited. This study focused on the diversity of yeasts and yeast-like organisms associated with matured fruits and fully open blossoms of apple, plum, and pear trees, during 2 consecutive years at 3 localities in southwest Slovakia. The occurrence of yeasts and yeast-like organisms in fruit samples was 2½ times higher and the yeast community more diverse than that in blossom samples. Only 2 species (Aureobasidium pullulans and Metschnikowia pulcherrima) occurred regularly in the blossom samples, whereas Galactomyces candidus, Hanseniaspora guilliermondii, Hanseniaspora uvarum, M. pulcherrima, Pichia kluyveri, Pichia kudriavzevii, and Saccharomyces cerevisiae were the most frequently isolated species from the fruit samples. The ratio of the number of samples where only individual species were present to the number of samples where 2 or more species were found (consortium) was counted. The occurrence of individual species in comparison with consortia was much higher in blossom samples than in fruit samples. In the latter, consortia predominated. Aureobasidium pullulans, M. pulcherrima, and S. cerevisiae, isolated from both the fruits and blossoms, can be considered as resident yeast species of various fruit tree species cultivated in southwest Slovakia localities. PMID:23210991

Vadkertiová, Renáta; Molnárová, Jana; Vránová, Dana; Sláviková, Elena

2012-12-01

383

Comparative Functional Genomics of the Fission Yeasts  

PubMed Central

The fission yeast clade, comprising Schizosaccharomyces pombe, S. octosporus, S. cryophilus and S. japonicus, occupies the basal branch of Ascomycete fungi and is an important model of eukaryote biology. A comparative annotation of these genomes identified a near extinction of transposons and the associated innovation of transposon-free centromeres. Expression analysis established that meiotic genes are subject to antisense transcription during vegetative growth, suggesting a mechanism for their tight regulation. In addition, trans-acting regulators control new genes within the context of expanded functional modules for meiosis and stress response. Differences in gene content and regulation also explain why, unlike the Saccharomycotina, fission yeasts cannot use ethanol as a primary carbon source. These analyses elucidate the genome structure and gene regulation of fission yeast and provide tools for investigation across the Schizosaccharomyces clade.

Rhind, Nicholas; Chen, Zehua; Yassour, Moran; Thompson, Dawn A; Haas, Brian J; Habib, Naomi; Wapinski, Ilan; Roy, Sushmita; Lin, Michael F.; Heiman, David I; Young, Sarah K; Furuya, Kanji; Guo, Yabin; Pidoux, Alison; Chen, Huei Mei; Robbertse, Barbara; Goldberg, Jonathan M.; Aoki, Keita; Bayne, Elizabeth H.; Berlin, Aaron M; Desjardins, Christopher A.; Dobbs, Edward; Dukaj, Livio; Fan, Lin; FitzGerald, Michael G; French, Courtney; Gujja, Sharvari; Hansen, Klavs; Keifenheim, Dan; Levin, Joshua Z.; Mosher, Rebecca A.; Muller, Carolin A.; Pfiffner, Jenna; Priest, Margaret; Russ, Carsten; Smialowska, Agata; Swoboda, Peter; Sykes, Sean M; Vaughn, Matthew; Vengrova, Sonya; Yoder, Ryan; Zeng, Qiandong; Allshire, Robin; Baulcombe, David; Birren, Bruce W.; Brown, William; Ekwall, Karl; Kellis, Manolis; Leatherwood, Janet; Levin, Henry; Margalit, Hanah; Martienssen, Rob; Nieduszynski, Conrad A.; Spatafora, Joseph W.; Friedman, Nir; Dalgaard, Jacob Z.; Baumann, Peter; Niki, Hironori; Regev, Aviv; Nusbaum, Chad

2011-01-01

384

Detection of Yeast Cells; Microfluidic Impedance Sensor  

NASA Astrophysics Data System (ADS)

A microelectromechanical system (MEMS) based biosensor was proposed for the rapid detection of pathogenic bacteria and contaminants that pose a threat to public health. In this study, experimental tests followed by finite element computer simulations were performed to selectively detect the quantity of yeast cells in a sample solution then was compared to a solution with no yeast cells. The impedance based biosensor detects the change in impedance caused by the presence of yeast cells between the electrodes integrated into microchannel walls that contain the target cells in a suspension medium. Microfluidic devices were fabricated by using two methods: traditional micromachining and photolithography for experimental purposes. An impedance analyzer was experimentally used for the measurement of the electrical impedance signals. Computer models based in COMSOL Multiphysics consisted of a long microchannel with two electrodes placed on opposite sides of the channel. Experimental data, simulation results and published data were compared and similar trends were found.

Hulea, Kelsey; Matune, Nicholas; Mabbott, Benjamin; Panta, Yogendra

2010-11-01

385

Yeast oligo-mediated genome engineering (YOGE).  

PubMed

High-frequency oligonucleotide-directed recombination engineering (recombineering) has enabled rapid modification of several prokaryotic genomes to date. Here, we present a method for oligonucleotide-mediated recombineering in the model eukaryote and industrial production host Saccharomyces cerevisiae , which we call yeast oligo-mediated genome engineering (YOGE). Through a combination of overexpression and knockouts of relevant genes and optimization of transformation and oligonucleotide designs, we achieve high gene-modification frequencies at levels that only require screening of dozens of cells. We demonstrate the robustness of our approach in three divergent yeast strains, including those involved in industrial production of biobased chemicals. Furthermore, YOGE can be iteratively executed via cycling to generate genomic libraries up to 10 (5) individuals at each round for diversity generation. YOGE cycling alone or in combination with phenotypic selections or endonuclease-based negative genotypic selections can be used to generate modified alleles easily in yeast populations with high frequencies. PMID:24160921

DiCarlo, James E; Conley, Andrew J; Penttilä, Merja; Jäntti, Jussi; Wang, Harris H; Church, George M

2013-12-20

386

Kinetochore asymmetry defines a single yeast lineage  

PubMed Central

Asymmetric cell division is of fundamental importance in biology as it allows for the establishment of separate cell lineages during the development of multicellular organisms. Although microbial systems, including the yeast Saccharomyces cerevisiae, are excellent models of asymmetric cell division, this phenotype occurs in all cell divisions; consequently, models of lineage-specific segregation patterns in these systems do not exist. Here, we report the first example of lineage-specific asymmetric division in yeast. We used fluorescent tags to show that components of the yeast kinetochore, the protein complex that anchors chromosomes to the mitotic spindle, divide asymmetrically in a single postmeiotic lineage. This phenotype is not seen in vegetatively dividing haploid or diploid cells. This kinetochore asymmetry suggests a mechanism for the selective segregation of sister centromeres to daughter cells to establish different cell lineages or fates. These results provide a mechanistic link between lineage-defining asymmetry of metazoa with unicellular eukaryotes.

Thorpe, Peter H.; Bruno, Joanne; Rothstein, Rodney

2009-01-01

387

YEASTS FROM THE NORTH SEA AND AMOCO CADIZ OIL  

EPA Science Inventory

The species and densities of yeasts isolated from North Sea waters before and after the production of oil were compared. Debaryomyces hansenii was the predominant species, but after oil production, Candida guillieromondii, a hydrocarbonoclastic yeast, was more commonly isolated a...

388

Factors Determining Translational Efficiency of mRNA in Yeast.  

National Technical Information Service (NTIS)

Killer virus of Saccharomyces cerevisiae is a cytoplasmically-inherited virus that confers on persistently-infected yeast cells the ability to secrete a protein toxin which kills uninfected yeast cells but to which infected cells, denoted killers, are res...

M. J. Leibowitz F. P. Barbone D. E. Georgopoulos

1991-01-01

389

[The yeast biofilm in human medicine].  

PubMed

In recent years, the role of Candida yeasts as causative agents of nosocomial infections has increased. One of the important virulence factors contributing to the development of such infections is biofilm production. This virulence factor enables yeast to colonize both native surfaces and artificial implants. The most common sources of infection are patients themselves, in particular the gastrointestinal tract and skin. The vectors of exogenous yeast infections are predominantly the hands of the health personnel and contaminated medical instruments. The adhesion of yeasts to the implant surfaces is determined both by implant surface and yeast characteristics. This is followed by proliferation and production of microcolonies and extracellular matrix. The final biofilm structure is also influenced by the production of hyphae and pseudohyphae. The entire process of biofilm production is controlled by numerous regulatory systems, with the key role being played by the quorum sensing system. Like the adhered bacterial cultures, candidas growing in the form of a biofilm are highly resistant to antimicrobial therapy. Resistance of yeast biofilms to antifungals is a complex process with multiple contributing factors. These are especially increased gene expression (e.g. genes encoding the so called multidrug efflux pumps), limited penetration of substances through the extracellular matrix, inhibited cell growth and altered microenvironment in deeper biofilm layers. The concentrations of antifungals able to effectively affect the biofilm cells exceed, by several orders of magnitude, the values of conventionally determined MICs. High biofilm resistance results in ineffective antifungal therapy of biofilm infections. Therefore, if possible, the colonized implant should be removed. Conservative therapy should involve antifungals with a proven effect on the biofilm (e.g. caspofungin). The most effective measure in fighting biofilm infections is prevention, especially adhering to aseptic techniques when manipulating with implants and their correct maintenance. PMID:17929219

R?zicka, Filip; Holá, Veronika; Votava, Miroslav

2007-08-01

390

Altered transcription in yeast expressing expanded polyglutamine  

PubMed Central

Expanded polyglutamine tracts are responsible for at least eight fatal neurodegenerative diseases. In mouse models, proteins with expanded polyglutamine cause transcriptional dysregulation before onset of symptoms, suggesting that this dysregulation may be an early event in polyglutamine pathogenesis. Transcriptional dysregulation and cellular toxicity may be due to interaction between expanded polyglutamine and the histone acetyltransferase CREB-binding protein. To determine whether polyglutamine-mediated transcriptional dysregulation occurs in yeast, we expressed polyglutamine tracts in Saccharomyces cerevisiae. Gene expression profiles were determined for strains expressing either a cytoplasmic or nuclear protein with 23 or 75 glutamines, and these profiles were compared to existing profiles of mutant yeast strains. Transcriptional induction of genes encoding chaperones and heat-shock factors was caused by expression of expanded polyglutamine in either the nucleus or cytoplasm. Transcriptional repression was most prominent in yeast expressing nuclear expanded polyglutamine and was similar to profiles of yeast strains deleted for components of the histone acetyltransferase complex Spt/Ada/Gcn5 acetyltransferase (SAGA). The promoter from one affected gene (PHO84) was repressed by expanded polyglutamine in a reporter gene assay, and this effect was mitigated by the histone deacetylase inhibitor, Trichostatin A. Consistent with an effect on SAGA, nuclear expanded polyglutamine enhanced the toxicity of a deletion in the SAGA component SPT3. Thus, an early component of polyglutamine toxicity, transcriptional dysregulation, is conserved in yeast and is pharmacologically antagonized by a histone deacetylase inhibitor. These results suggest a therapeutic approach for treatment of polyglutamine diseases and provide the potential for yeast-based screens for agents that reverse polyglutamine toxicity.

Hughes, Robert E.; Lo, Russell S.; Davis, Colleen; Strand, Andrew D.; Neal, Cassandra L.; Olson, James M.; Fields, Stanley

2001-01-01

391

Effect of anti-glycosphingolipid monoclonal antibodies in pathogenic fungal growth and differentiation. Characterization of monoclonal antibody MEST-3 directed to Manp?1->3Manp?1->2IPC  

PubMed Central

Background Studies carried out during the 1990's demonstrated the presence of fungal glycoinositol phosphorylceramides (GIPCs) with unique structures, some of them showed reactivity with sera of patients with histoplasmosis, paracoccidioidomycosis or aspergillosis. It was also observed that fungal GIPCs were able to inhibit T lymphocyte proliferation "in vitro", and studies regarding the importance of these molecules to fungal survival showed that many species of fungi are vulnerable to inhibitors of sphingolipid biosynthesis. Results In this paper, we describe a detailed characterization of an IgG2a monoclonal antibody (mAb), termed MEST-3, directed to the Paracoccidioides brasiliensis glycolipid antigen Pb-2 (Manp?1?3Manp?1?2IPC). mAb MEST-3 also recognizes GIPCs bearing the same structure in other fungi. Studies performed on fungal cultures clearly showed the strong inhibitory activity of MEST-3 on differentiation and colony formation of Paracoccidioides brasiliensis, Histoplasma capsulatum and Sporothrix schenckii. Similar inhibitory results were observed when these fungi where incubated with a different mAb, which recognizes GIPCs bearing terminal residues of ?-D-galactofuranose linked to mannose (mAb MEST-1). On the other hand, mAb MEST-2 specifically directed to fungal glucosylceramide (GlcCer) was able to promote only a weak inhibition on fungal differentiation and colony formation. Conclusions These results strongly suggest that mAbs directed to specific glycosphingolipids are able to interfere on fungal growth and differentiation. Thus, studies on surface distribution of GIPCs in yeast and mycelium forms of fungi may yield valuable information regarding the relevance of glycosphingolipids in processes of fungal growth, morphological transition and infectivity.

2010-01-01

392

Principles of chromosomal organization: lessons from yeast  

PubMed Central

The spatial organization of genes and chromosomes plays an important role in the regulation of several DNA processes. However, the principles and forces underlying this nonrandom organization are mostly unknown. Despite its small dimension, and thanks to new imaging and biochemical techniques, studies of the budding yeast nucleus have led to significant insights into chromosome arrangement and dynamics. The dynamic organization of the yeast genome during interphase argues for both the physical properties of the chromatin fiber and specific molecular interactions as drivers of nuclear order.

Zimmer, Christophe

2011-01-01

393

Three's company: The fission yeast actin cytoskeleton  

PubMed Central

How the actin cytoskeleton assembles into different structures to drive diverse cellular processes is a fundamental cell biological question. In addition to orchestrating the appropriate combination of regulators and actin-binding proteins, different actin-based structures must insulate themselves from one another to maintain specificity within a crowded cytoplasm. Actin specification is particularly vexing in complex eukaryotes where a multitude of protein isoforms and actin structures operate within the same cell. Fission yeast Schizosaccharomyces pombe possesses a single actin isoform that functions in three distinct structures throughout the cell cycle. In this review, we explore recent studies in fission yeast that help unravel how different actin structures operate in cells.

Kovar, David R.; Sirotkin, Vladimir; Lord, Matthew

2010-01-01

394

Understanding cytokinesis: lessons from fission yeast  

PubMed Central

For decades after the discovery that a contractile ring made of actin filaments and myosin II produces the force to constrict the cleavage furrow of animal cells, the complexity of cytokinesis has slowed progress in understanding the mechanism. Mechanistic insights, however, have been obtained by genetic, biochemical, microscopic and mathematical modelling approaches in the fission yeast Schizosaccharomyces pombe. Many features that have been identified in fission yeast are probably shared with animal cells, as both inherited many cytokinesis genes from their common ancestor about one billion years ago.

Pollard, Thomas D.; Wu, Jian-Qiu

2010-01-01

395

Mitochondrial Network Size Scaling in Budding Yeast**  

PubMed Central

Mitochondria must grow with the growing cell to ensure proper cellular physiology and inheritance upon division. We measured the physical size of mitochondrial networks in budding yeast and found that mitochondrial network size increased with increasing cell size and that this scaling relation occurred primarily in the bud. The mitochondria to cell size ratio continually decreased in aging mothers over successive generations. However, regardless of mother age or mitochondrial content, all buds attained the same average ratio. Thus, yeast populations achieve a stable scaling relation between mitochondrial content and cell size despite asymmetry in inheritance.

Rafelski, Susanne M.; Viana, Matheus P.; Zhang, Yi; Chan, Yee-Hung M.; Thorn, Kurt S.; Yam, Phoebe; Fung, Jennifer C.; Li, Hao; Costa, Luciano da F.; Marshall, Wallace F.

2013-01-01

396

Modeling ALS and FTLD proteinopathies in yeast  

PubMed Central

In recent years there have been several reports of human neurodegenerative diseases that involve protein misfolding being modeled in the yeast Saccharomyces cerevisiae. This review summarizes recent advances in understanding the specific mechanisms underlying intracellular neuronal pathology during Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD), including SOD1, TDP-43 and FUS protein inclusions and the potential of these proteins to be involved in pathogenic prion-like mechanisms. More specifically, we focus on findings from yeast systems that offer tremendous possibilities for screening for genetic and chemical modifiers of disease-related proteotoxicity.

2011-01-01

397

Insights into molecular evolution from yeast genomics.  

PubMed

Enabled by comparative genomics, yeasts have increasingly developed into a powerful model system for molecular evolution. Here we survey several areas in which yeast studies have made important contributions, including regulatory evolution, gene duplication and divergence, evolution of gene order and evolution of complexity. In each area we highlight key studies and findings based on techniques ranging from statistical analysis of large datasets to direct laboratory measurements of fitness. Future work will combine traditional evolutionary genetics analysis and experimental evolution with tools from systems biology to yield mechanistic insight into complex phenotypes. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24760744

Zarin, Taraneh; Moses, Alan M

2014-07-01

398

Buckling of yeast modeled as viscoelastic shells with transverse shearing  

Microsoft Academic Search

Yeast cells can be regarded as micron-sized and liquid-filled cylindrical shells. Owing to the rigid cell walls, yeast cells\\u000a can bear compressive forces produced during the biotechnological process chain. However, when the compressive forces applied\\u000a on the yeast go beyond a critical value, mechanical buckling will occur. Since the buckling of the yeast can change the networks\\u000a in its cellular

Yiming Fu; Jin Zhang

399

Biochemical characteristics of osmophilic yeasts isolated from pollens and honey.  

PubMed

A total of 1752 strains of osmophilic yeasts were isolated from honey and pollens. Forty-three strains of osmophilic yeasts produced polyols, among which 6 strains produced erythritol in good yields. On the other hand, 52 osmophilic yeasts converted sucrose to fructooligosaccharides, among which 8 strains produced both extra and intracellular beta-fructofuranosidase, which converted sucrose to fructooligosaccharides. This investigation concluded that osmophilic yeasts converted sucrose not only to polyols, but also to fructooligosaccharides in good yields. PMID:8987865

Park, Y K; Koo, M H; Oliveira, I M

1996-11-01

400

[Effect of stress on the composition of yeast lipids].  

PubMed

Pigmented (Rhodotorula glutinis) and nonpigmented (Lipomyces starkeyi) yeasts were studied. Exogenous stressors (UV irradiation and methylene blue) were shown to change the composition of yeast lipids (especially the ratio of unsaturated fatty acids) and to increase the content of lipid peroxidation products formed (particularly in nonpigmented yeasts). In carotene-synthesizing yeasts, these stressors decreased the amount of carotenoids produced and did not affect the ratio between carotenoid pigments (beta-carotene, torulene, and torularhodin). PMID:10752082

Zalashko, M V; Salokhina, G A; Koroleva, I F

2000-01-01

401

[Growth of epiphytic and soil yeasts on wheat seedlings].  

PubMed

Colonization of wheat seedlings by epiphytic (Rhodotorula glutinis) and soil (Lipomyces starkeyi) yeasts was studied by scanning electron microscopy. Epiphytic yeast cells dominated on the plant surface. Soil yeast cells were randomly distributed among both the zones of a seedling and the particles of an inorganic substrate. It has been found that epiphytic yeast strains can readily grow on the surface of a plant. PMID:561879

Guzeva, I S; Guzev, V S; Bab'eva, I P; Zviagintsev, D G

1977-01-01

402

Global Gene Expression Analysis of Yeast Cells during Sake Brewing  

Microsoft Academic Search

During the process of brewing Japanese sake, rice starch is saccharified by enzymes produced by koji (Aspergillus oryzae), and the resultant glucose is fermented to ethanol by sake yeast (Saccharomyces cerevisiae). This process allows a highly con- densed mash to be made without accumulation of high levels of sugars, which inhibit yeast cell growth and ethanol fermenta- tion. Thus, yeast

Hong Wu; Xiaohong Zheng; Yoshio Araki; Hiroshi Sahara; Hiroshi Takagi; Hitoshi Shimoi

2006-01-01

403

Growth and survival of a probiotic yeast in dairy products  

Microsoft Academic Search

Poor survival of probiotic bacteria in yogurt has been recorded. Growth of a probiotic yeast, Saccharomyces boulardii, in association with the bio-yogurt microflora, by incorporating the yeast into commercial bio-yogurt, has been suggested to stimulate the growth of the probiotic organisms and to assure their survival during shelflife. Therefore, the ability of growth and survival of the probiotic yeast itself

A Lourens-Hattingh; B. C Viljoen

2001-01-01

404

Enhanced CO2 Production by Yeast Exposed to Elevated Temperatures  

Microsoft Academic Search

SUMMARY After starvation, yeast exposed to elevated temperatures produced CO, twice as fast as unexposed organisms. The lag which preceded linear CO, pro- duction by starved yeast was essentially eliminated by heat treatment. Uptake and retention of sorbose was greater in heated yeast. Heating was accomplished by brief immersion of the organisms in heated solutions and by growth for 2

E. Spoerl

1970-01-01

405

Acetic acid production by Dekkera\\/Brettanomyces yeasts  

Microsoft Academic Search

Yeast belonging to the genera Brettanomyces and Dekkera are noted for spoiling cellar and bottled wine through the production of haze, turbidity and acetic acid. However, I was unable to find information on the use of these yeasts for the expressed purpose of acetic acid production. Sixty yeast strains belonging to these, and several other genera, from the ARS Culture

S. N. Freer

2002-01-01

406

GENE ENGINEERING OF YEASTS FOR THE DEGRADATION OF HAZARDOUS WASTE  

EPA Science Inventory

The research examined the structure and function of cytochrome P-450 genes in yeast as a model for gene engineering such as eukaryotic P-450 enzymes for biodegradation of hazardous waste by yeasts. Saccharomyces cerevisiae and Candida tropicalis are two yeasts known to produce ma...

407

21 CFR 172.381 - Vitamin D2 bakers yeast.  

Code of Federal Regulations, 2013 CFR

...bakers yeast. (c) The additive may be used in yeast-leavened baked goods and baking mixes and yeast-leavened baked snack foods at levels not to exceed 400 International Units of vitamin D2 per 100 grams in the finished food. (d) To...

2013-04-01

408

Yeast identification in floral nectar of Mimulus aurantiacus (Invited)  

Microsoft Academic Search

Nectar is such a sugar-rich resource that serves as a natural habitat in which microbes thrive. As a result, yeasts arrive to nectar on the bodies of pollinators such as hummingbirds and bees. Yeasts use the sugar in nectar for their own needs when introduced. This research focuses on the identification of different types of yeast that are found in

C. Kyauk; M. Belisle; T. Fukami

2009-01-01

409

Production of lipid compounds in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

This review describes progress using the yeast Saccharomyces cerevisiae as a model organism for the fast and efficient analysis of genes and enzyme activities involved in the lipid biosynthetic pathways of several donor organisms. Furthermore, we assess the impact of baker's yeast on the production of novel, high-value lipid compounds. Yeast can be genetically modified to produce selected substances in

M. Veen; C. Lang

2004-01-01

410

5 Brewer's yeast: genetic structure and targets for improvement  

Microsoft Academic Search

The art of beer brewing is ancient, and Saccharomyces yeast probably played a pivotal role from the beginning. Production of beer from the barley grain consists of multiple Steps, of which only the last few involve the yeast. Nevertheless, the behaviour of the yeast is highly decisive for both Speed and outcome of the whole process, and to a large

Jørgen Hansen; Morten C. Kielland-Brandt

411

Industrial yeast strain engineered to ferment ethanol from lignocellulosic biomass  

Microsoft Academic Search

In this study an industrial Saccharomyces cerevisiae yeast strain capable of fermenting ethanol from pretreated lignocellulosic material was engineered. Genes encoding cellulases (endoglucanase, exoglucanase and ?-glucosidase) were integrated into the chromosomal ribosomal DNA and delta regions of a derivative of the K1-V1116 wine yeast strain. The engineered cellulolytic yeast produces ethanol in one step thr