Characterization of Paracoccidioides brasiliensis by FT-IR spectroscopy and nanotechnology

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Ferreira, Isabelle; Ferreira-Strixino, Juliana; Castilho, Maiara L.; Campos, Claudia B. L.; Tellez, Claudio; Raniero, Leandro

2016-01-01

Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, is a dimorphic fungus existing as mycelia in the environment (or at 25 °C in vitro) and as yeast cells in the human host (or at 37 °C in vitro). Because mycological examination of lesions in patients frequently is unable to show the presence of the fungus and serological tests can misdiagnose the disease with other mycosis, the development of new approach's for molecular identification of P. brasiliensis spurges is needed. This study describes the use of a gold nanoprobe of a known gene sequence of P. brasiliensis as a molecular tool to identify P. brasiliensis by regular polymerase chain reaction (PCR) associated with a colorimetric methods. This approach is suitable for testing in remote areas because it does not require any further step than gene amplification, being safer and cheaper than electrophoresis methods. The proposed test showed a color change of the PCR reaction mixture from red to blue in negative samples, whereas the solution remains red in positive samples. We also performed a Fourier Transform Infrared (FT-IR) Spectroscopy analysis to characterize and compare the chemical composition between yeast and mycelia forms, which revealed biochemical differences between these two forms. The analysis of the spectra showed that differences were distributed in chemical bonds of proteins, lipids and carbohydrates. The most prominent difference between both forms was vibration modes related to 1,3-β-glucan usually found in mycelia and 1,3-α-glucan found in yeasts and also chitin forms. In this work, we introduce FT-IR as a new method suitable to reveal overall differences that biochemically distinguish each form of P. brasiliensis that could be additionally used to discriminate biochemical differences among a single form under distinct environmental conditions.

Antibodies against glycolipids enhance antifungal activity of macrophages and reduce fungal burden after infection with Paracoccidioides brasiliensis

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Renata Amelia eBueno

2016-02-01

Full Text Available Paracoccidioidomycosis is a fungal disease endemic in Latin America. Polyclonal antibodies to acidic glycosphingolipids (GSLs from Paracoccidioides brasiliensis opsonized yeast forms in vitro increasing phagocytosis and reduced the fungal burden of infected animals. Antibodies to GSL were active in both prophylactic and therapeutic protocols using a murine intratracheal infection model. Pathological examination of the lungs of animals treated with antibodies to GSL showed well-organized granulomas and minimally damaged parenchyma compared to the untreated control. Murine peritoneal macrophages activated by IFN-γ and incubated with antibodies against acidic GSLs more effectively phagocytosed and killed P. brasiliensis yeast cells as well as produced more nitric oxide compared to controls. The present work discloses a novel target of protective antibodies against P. brasiliensis adding to other well-studied mediators of the immune response to this fungus.

Detection of Antibodies against Paracoccidioides brasiliensis Melanin in In Vitro and In Vivo Studies during Infection ▿

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

2011-01-01

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 anti...

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

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Pereira Maristela

2009-12-01

Full Text Available Abstract 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.

Performance of yeast-baited traps with Triatoma sordida, Triatoma brasiliensis, Triatoma pseudomaculata, and Panstrongylus megistus in laboratory assays Rendimiento de trampas cebadas con levaduras en la captura de Triatoma sordida, Triatoma brasiliensis, Triatoma pseudomaculata y Panstrongylus megistus en experimentos de laboratorio

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Herton H. R. Pires

2000-06-01

Full Text Available The effectiveness of a trap for triatomines baited with yeast cultures has been previously demonstrated for Triatoma infestans in laboratory assays. We report here results from laboratory assays testing yeast traps for Triatoma sordida, Triatoma brasiliensis, Triatoma pseudomaculata, and Panstrongylus megistus. All assays were conducted in an open experimental arena 100 cm X 100 cm, with two traps placed at opposite sides of the arena. One of the traps contained a yeast culture, and the other trap contained a saccharose solution as a control. Two series of experiments were done, one without a refuge for the insects and one with a refuge. The results obtained clearly demonstrated that the yeast-baited traps were effective in the laboratory in capturing both T. sordida and P. megistus. For T. sordida, yeast-baited traps captured significantly more bugs than did the control traps (t test P value = 0.03. For P. megistus, when a refuge was provided during the assay, yeast-baited traps also captured significantly more bugs than did the control traps (t test P value = 0.006. In the experiments with T. brasiliensis and T. pseudomaculata, both traps captured some insects, but the yeast traps captured many fewer bugs than was true with the T. sordida and P. megistus bugs. These results indicate that, in the laboratory, yeast traps can capture considerable numbers of T. sordida and P. megistus in one night. We discuss the potential use of yeast traps for detecting and capturing both triatomine species.Con anterioridad se ha demostrado la eficacia de las trampas cebadas con cultivos de levaduras (TCL para capturar Triatoma infestans en experimentos de laboratorio. En el presente estudio se describen los resultados obtenidos con estas trampas para capturar T. sordida, T. brasiliensis, T. pseudomaculata y Panstrongylus megistus, también en experimentos de laboratorio. Todos los experimentos fueron realizados en un recinto experimental abierto de 100 cm por

Effect of ArtinM on Human Blood Cells During Infection With Paracoccidioides brasiliensis.

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Ruas, Luciana P; Genaro, Livia M; Justo-Junior, Amauri S; Coser, Lilian O; de Castro, Lívia F; Trabasso, Plinio; Mamoni, Ronei L; Roque-Barreira, Maria-Cristina; Blotta, Maria-Heloisa S L

2018-01-01

Infections caused by fungi are prominent in our environment and can be potentially fatal. paracoccidioidomycosis (PCM), caused by fungi of the Paracoccidioides genus, is the most frequent systemic mycosis in Brazil and the main cause of death among immunocompetent individuals. The antifungal therapy for PCM is usually effective but side effects and relapses are often reported. The latter could be avoided with alternative or complementary therapies aimed at boosting the immune response to combat this pathogen. Recent reports have pointed at the importance of an effective cellular immune response, with the participation of Th1 cells, in the resistance to and control of Paracoccidioides infection. The ArtinM lectin, extracted from jackfruit ( Artocarpus heterophyllus ) seeds, exhibits immunomodulatory activity against several intracellular pathogens, including Paracoccidioides brasiliensis , by promoting the development of a Th1 immune response. The aim of this work was to characterize the effect of ArtinM on peripheral blood cells of patients with PCM and on those of control individuals infected with fungal yeasts cells in vitro . Our results demonstrate that ArtinM activates human neutrophils in vitro , leading to an increase in cytokine production and CD54 expression. ArtinM activated P. brasiliensis -infected neutrophils from both healthy individuals and patients with PCM. This activation was not dependent on the dectin-1 receptor, because pre-incubation with laminarin, a dectin-1 receptor blocker, did not reverse the activated state of the cells. ArtinM also stimulated human peripheral blood mononuclear cells to secrete pro-inflammatory Th1-related cytokines, which are protective against Paracoccidioides infection. These data support the immunostimulatory action of ArtinM and encourage new studies using the lectin for the immunotherapy of PCM.

Effect of ArtinM on Human Blood Cells During Infection With Paracoccidioides brasiliensis

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Luciana P. Ruas

2018-05-01

Full Text Available Infections caused by fungi are prominent in our environment and can be potentially fatal. paracoccidioidomycosis (PCM, caused by fungi of the Paracoccidioides genus, is the most frequent systemic mycosis in Brazil and the main cause of death among immunocompetent individuals. The antifungal therapy for PCM is usually effective but side effects and relapses are often reported. The latter could be avoided with alternative or complementary therapies aimed at boosting the immune response to combat this pathogen. Recent reports have pointed at the importance of an effective cellular immune response, with the participation of Th1 cells, in the resistance to and control of Paracoccidioides infection. The ArtinM lectin, extracted from jackfruit (Artocarpus heterophyllus seeds, exhibits immunomodulatory activity against several intracellular pathogens, including Paracoccidioides brasiliensis, by promoting the development of a Th1 immune response. The aim of this work was to characterize the effect of ArtinM on peripheral blood cells of patients with PCM and on those of control individuals infected with fungal yeasts cells in vitro. Our results demonstrate that ArtinM activates human neutrophils in vitro, leading to an increase in cytokine production and CD54 expression. ArtinM activated P. brasiliensis-infected neutrophils from both healthy individuals and patients with PCM. This activation was not dependent on the dectin-1 receptor, because pre-incubation with laminarin, a dectin-1 receptor blocker, did not reverse the activated state of the cells. ArtinM also stimulated human peripheral blood mononuclear cells to secrete pro-inflammatory Th1-related cytokines, which are protective against Paracoccidioides infection. These data support the immunostimulatory action of ArtinM and encourage new studies using the lectin for the immunotherapy of PCM.

Nocardia brasiliensis cell wall lipids modulate macrophage and dendritic responses that favor development of experimental actinomycetoma in BALB/c mice.

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Trevino-Villarreal, J Humberto; Vera-Cabrera, Lucio; Valero-Guillén, Pedro L; Salinas-Carmona, Mario C

2012-10-01

Nocardia brasiliensis is a Gram-positive facultative intracellular bacterium frequently isolated from human actinomycetoma. However, the pathogenesis of this infection remains unknown. Here, we used a model of bacterial delipidation with benzine to investigate the role of N. brasiliensis cell wall-associated lipids in experimental actinomycetoma. Delipidation of N. brasiliensis with benzine resulted in complete abolition of actinomycetoma without affecting bacterial viability. Chemical analyses revealed that trehalose dimycolate and an unidentified hydrophobic compound were the principal compounds extracted from N. brasiliensis with benzine. By electron microscopy, the extracted lipids were found to be located in the outermost membrane layer of the N. brasiliensis cell wall. They also appeared to confer acid-fastness. In vitro, the extractable lipids from the N. brasiliensis cell wall induced the production of the proinflammatory cytokines interleukin-1β (IL-1β), IL-6, and CCL-2 in macrophages. The N. brasiliensis cell wall extractable lipids inhibited important macrophage microbicidal effects, such as tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) production, phagocytosis, bacterial killing, and major histocompatibility complex class II (MHC-II) expression in response to gamma interferon (IFN-γ). In dendritic cells (DCs), N. brasiliensis cell wall-associated extractable lipids suppressed MHC-II, CD80, and CD40 expression while inducing tumor growth factor β (TGF-β) production. Immunization with delipidated N. brasiliensis induced partial protection preventing actinomycetoma. These findings suggest that N. brasiliensis cell wall-associated lipids are important for actinomycetoma development by inducing inflammation and modulating the responses of macrophages and DCs to N. brasiliensis.

Differences in cell morphometry, cell wall topography and gp70 expression correlate with the virulence of Sporothrix brasiliensis clinical isolates.

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Rafaela A Castro

Full Text Available 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.

Immunoglobulins and C3 in the P. brasiliensis granuloma

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Lilian M. V. Biagioni

1987-04-01

Full Text Available The experimental model of paracoccidioidomycosis induced in mice by the intravenous injection of yeast-forms of P. brasiliensis (Bt2 strain; 1 x 10(6 viable fungi/animal was used to evaluate sequentially 2, 4, 8, 16 and 20 weeks after inoculation: 1. The presence of immunoglobulins and C3 in the pulmonary granuloma-ta, by direct immunofluorescence; 2. The humoral (immunodiffusion test and the cellular (footpad sweeling test immune response; 3. The histopathology of lesions. The cell-immune response was positive since week 2, showing a transitory depression at week 16. Specific antibodies were first detected at week 4 and peaked at week 16. At histology, epithelioid granulomas with numerous fungi and polymorphonuclear agreggates were seen. The lungs showed progressive involvement up to week 16, with little decrease at week 20. From week 2 on, there were deposits of IgG and C3 around fungal walls within the granulomas and IgG stained cells among the mononuclear cell peripheral halo. Interstitital immunoglobulins and C3 deposits in the granulomas were not letected. IgG and C3 seen to play an early an important role in. the host defenses against P. brasiliensis by possibly cooperating in the killing of parasites and blocking the antigenic diffusion.

IL-4Rα-associated antigen processing by B cells promotes immunity in Nippostrongylus brasiliensis infection.

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William G C Horsnell

2013-10-01

Full Text Available In this study, B cell function in protective T(H2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4Rα and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4Rα⁻/⁻ 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-4Rα expressing B cells into naïve BALB/c mice, but not IL-4Rα 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-4Rα-responsive B cells producing IL-13 contribute significantly to CD4⁺ T cell-mediated protective immunity against N. brasiliensis infection.

New developments of RNAi in Paracoccidioides brasiliensis: prospects for high-throughput, genome-wide, functional genomics.

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Tercio Goes

2014-10-01

Full Text Available The Fungal Genome Initiative of the Broad Institute, in partnership with the Paracoccidioides research community, has recently sequenced the genome of representative isolates of this human-pathogen dimorphic fungus: Pb18 (S1, Pb03 (PS2 and Pb01. The accomplishment of future high-throughput, genome-wide, functional genomics will rely upon appropriate molecular tools and straightforward techniques to streamline the generation of stable loss-of-function phenotypes. In the past decades, RNAi has emerged as the most robust genetic technique to modulate or to suppress gene expression in diverse eukaryotes, including fungi. These molecular tools and techniques, adapted for RNAi, were up until now unavailable for P. brasiliensis.In this paper, we report Agrobacterium tumefaciens mediated transformation of yeast cells for high-throughput applications with which higher transformation frequencies of 150±24 yeast cell transformants per 1×106 viable yeast cells were obtained. Our approach is based on a bifunctional selective marker fusion protein consisted of the Streptoalloteichus hindustanus bleomycin-resistance gene (Shble and the intrinsically fluorescent monomeric protein mCherry which was codon-optimized for heterologous expression in P. brasiliensis. We also report successful GP43 gene knock-down through the expression of intron-containing hairpin RNA (ihpRNA from a Gateway-adapted cassette (cALf which was purpose-built for gene silencing in a high-throughput manner. Gp43 transcript levels were reduced by 73.1±22.9% with this approach.We have a firm conviction that the genetic transformation technique and the molecular tools herein described will have a relevant contribution in future Paracoccidioides spp. functional genomics research.

Nocardia brasiliensis induces formation of foamy macrophages and dendritic cells in vitro and in vivo.

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Irene Meester

Full Text Available 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.

Nocardia brasiliensis induces formation of foamy macrophages and dendritic cells in vitro and in vivo.

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

2014-01-01

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.

Granulocyte macrophage colony-stimulating factor enhances the modulatory effect of cytokines on monocyte-derived multinucleated giant cell formation and fungicidal activity against Paracoccidioides brasiliensis

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Magda Paula Pereira do Nascimento

2011-09-01

Full Text Available Multinucleated giant cells (MGC are cells present in characteristic granulomatous inflammation induced by intracellular infectious agents or foreign materials. The present study evaluated the modulatory effect of granulocyte macrophage colony-stimulating factor (GM-CSF in association with other cytokines such as interferon-gamma (IFN-γ, tumour necrosis factor-alpha, interleukin (IL-10 or transforming growth factor beta (TGF-β1 on the formation of MGC from human peripheral blood monocytes stimulated with Paracoccidioides brasiliensis antigen (PbAg. The generation of MGC was determined by fusion index (FI and the fungicidal activity of these cells was evaluated after 4 h of MGC co-cultured with viable yeast cells of P. brasiliensis strain 18 (Pb18. The results showed that monocytes incubated with PbAg and GM-CSF plus IFN-γ had a significantly higher FI than in all the other cultures, while the addition of IL-10 or TGF-β1 had a suppressive effect on MGC generation. Monocytes incubated with both pro and anti-inflammatory cytokines had a higher induction of foreign body-type MGC rather than Langhans-type MGC. MGC stimulated with PbAg and GM-CSF in association with the other cytokines had increased fungicidal activity and the presence of GM-CSF also partially inhibited the suppressive effects of IL-10 and TGF-β1. Together, these results suggest that GM-CSF is a positive modulator of PbAg-stimulated MGC generation and on the fungicidal activity against Pb18.

Genetic Diversity of Pectobacterium carotovorum subsp. brasiliensis Isolated in Korea

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Dong Hwan Lee

2014-06-01

Full Text Available The plant pathogenic bacterial genus Pectobacteirum consists of heterogeneous strains. The P. carotovorum species is a complex strain showing divergent characteristics, and a new subspecies named P. carotovorum subsp. brasiliensis has been identified recently. In this paper, we re-identified the P. carotovorum subsp. brasiliensis isolates from those classified under the subspecies carotovorum and newly isolated P. carotovorum subsp. brasiliensis strains. All isolates were able to produce plant cell-wall degrading enzymes such as pectate lyase, polygalacturonase, cellulase and protease. We used genetic and biochemical methods to examine the diversity of P. carotovorum subsp. brasiliensis isolates, and found genetic diversity within the brasiliensis subsp. isolates in Korea. The restriction fragment length polymorphism analysis based on the recA gene revealed a unique pattern for the brasiliensis subspecies. The Korean brasiliensis subsp. isolates were divided into four clades based on pulsed-field gel electrophoresis. However, correlations between clades and isolated hosts or year could not be found, suggesting that diverse brasiliensis subsp. isolates existed.

In vitro susceptibility of Paracoccidioides brasiliensis yeast form to antifungal agents Susceptibilidad in vitro de la forma levaduriforme de Paracoccidioides brasiliensis a los agentes antifungicos

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Angela Restrepo

1984-12-01

Full Text Available A study was conducted to determine the susceptibility of P. brasiliensis yeast form to amphotericin B (A, ketoconazole (K, 5-fluorocytosine (5-FC and rifampin (R. The three isolates tested produced minimal inhibitory concentrations (MICs (mcg/ml in the following range: A: 0.09-0.18; K: 0.001-0.007; 5-FC: 62.5-250 and R: 40-80. The minimal fungicidal concentrations (MFC were several times higher than the corresponding MICs. Precise MFC for 5-FC were not obtained (> 500 mcg/ml. Combination of K plus A proved synergic, with the fractional inhibitory concentration (FIC indices revealing synergy when the drugs were combined at the 1 to 1 and 1 to 5 MIC ratios. R (40 mcg/ml appeared to antagonize K. These results indicate promise for the combined use of K plus A as a therapeutical regimen.Se realizó un estudio con el objeto de determinar la susceptibilidad de la fase levaduri-forme del P. brasiliensis a la Anfotericina B (A, el Ketoconazol (K, la 5-fluorocitosina (5-FC y la rifampicina. Las 3 cepas estudiadas tuvieron las siguientes concentraciones inhibitorias mínimas (MIC (mcg/ml A: 0.09-0.18; K: 0.001-0.007; 5-FC: 62.5-250 y R: 40-80. Las concentraciones fungicidas mínimas (MFC resultaron más altas que las MICs correspondientes. En el caso de la 5-FC no se obtuvo una cifra MFC precisa (> 500 mcg/ml. La combinación de K más A mostró ser sinérgica al combinarse las drogas en relación 1:1 y 1:5 de los MICs respectivos. R (40 mcg/ml se mostró antagonista del K. Los resultados indican que la combinación A + K pudiera constituir un adecuado régimen terapéutico en ciertos pacientes.

Efficacy of a poly-aggregated formulation of amphotericin B in treating systemic sporotrichosis caused by Sporothrix brasiliensis.

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Ishida, Kelly; Castro, Rafaela Alves; Torrado, Juan J; Serrano, Dolores Remedios; Borba-Santos, Luana Pereira; Quintella, Leonardo Pereira; de Souza, Wanderley; Rozental, Sonia; Lopes-Bezerra, Leila M

2018-04-01

In severe cases of sporotrichosis, it is recommended to use amphotericin B deoxycholate (D-AMB) or its lipid formulations and/or in association with itraconazole (ITC). Our aim was to evaluate the antifungal efficacy of a poly-aggregated amphotericin B (P-AMB), a nonlipid formulation, compared with D-AMB on systemic sporotrichosis caused by Sporothrix brasiliensis. In vitro assays showed that Sporothrix schenckii sensu stricto and S. brasiliensis yeast clinical isolates were susceptible to low concentrations of P-AMB and D-AMB. Although P-AMB presented a higher minimal inhibitory concentration (MIC) compared to D-AMB, its cytotoxic effect on renal cells and erythrocytes was lower. For the in vivo assays, male BALB/c mice were intravenously infected with S. brasiliensis yeasts, and P-AMB or D-AMB was administered 3 days post-infection. The efficacy of five therapeutic regimens was tested: intravenous monotherapy with P-AMB or D-AMB, intravenous pulsed-therapy with P-AMB or D-AMB, and intravenous therapy with P-AMB, followed by oral ITC. These treatments increased murine survival and controlled the fungal burden in the liver, spleen, lungs, and kidneys. However, only D-AMB monotherapy or the pulsed-therapies with D-AMB or P-AMB led to 100% survival of the mice 45 days post-infection; only pulsed administration of D-AMB was able to control the fungal load in all organs 45 days post-infection. Accordingly, the histopathological findings showed reductions in the fungal burden and inflammatory reactions in these treatment regimens. Together, our results suggest that the P-AMB formulation could be considered as an alternative drug to D-AMB for treating disseminated sporotrichosis.

Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts.

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Palková, Zdena; Váchová, Libuše

2016-09-01

Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

Immobilization of yeast cells by radiation-induced polymerization

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Fujimura, T.; Kaetsu, I.

1982-01-01

Radiation-induced polymerization method was applied to the immobilization of yeast cells. The effects of irradiation, cooling and monomer, which are neccessary for polymerization, were recovered completely by subsequent aerobical incubation of yeast cells. The ethanol productive in immobilized yeast cells increased with the increase of aerobical incubation period. The growth of yeast cells in immobilized yeast cells was indicated. The maximum ethanol productivity in immobilized yeast cell system was around three times as much as that in free yeast cell system. (orig.)

Monoclonal antibodies to Nocardia asteroides and Nocardia brasiliensis antigens.

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Jiménez, T; Díaz, A M; Zlotnik, H

1990-01-01

Nocardia asteroides and Nocardia brasiliensis whole-cell extracts were used as antigens to generate monoclonal antibodies (MAbs). Six stable hybrid cell lines secreting anti-Nocardia spp. MAbs were obtained. These were characterized by enzyme-linked immunosorbent assay, Western blot (immunoblot), and immunofluorescence assay. Although all the MAbs exhibited different degrees of cross-reactivity with N. asteroides and N. brasiliensis antigens as well as with culture-filtrate antigens from Myco...

Endoplasmic reticulum involvement in yeast cell death

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Nicanor Austriaco, O.

2012-01-01

Yeast cells undergo programed cell death (PCD) with characteristic markers associated with apoptosis in mammalian cells including chromatin breakage, nuclear fragmentation, reactive oxygen species generation, and metacaspase activation. Though significant research has focused on mitochondrial involvement in this phenomenon, more recent work with both Saccharomyces cerevisiae and Schizosaccharomyces pombe has also implicated the endoplasmic reticulum (ER) in yeast PCD. This minireview provides an overview of ER stress-associated cell death (ER-SAD) in yeast. It begins with a description of ER structure and function in yeast before moving to a discussion of ER-SAD in both mammalian and yeast cells. Three examples of yeast cell death associated with the ER will be highlighted here including inositol starvation, lipid toxicity, and the inhibition of N-glycosylation. It closes by suggesting ways to further examine the involvement of the ER in yeast cell death.

Exploring virulence and immunogenicity in the emerging pathogen Sporothrix brasiliensis.

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Della Terra, Paula Portella; Rodrigues, Anderson Messias; Fernandes, Geisa Ferreira; Nishikaku, Angela Satie; Burger, Eva; de Camargo, Zoilo Pires

2017-08-01

Sporotrichosis is a polymorphic chronic infection of humans and animals classically acquired after traumatic inoculation with soil and plant material contaminated with Sporothrix spp. propagules. An alternative and successful route of transmission is bites and scratches from diseased cats, through which Sporothrix yeasts are inoculated into mammalian tissue. The development of a murine model of subcutaneous sporotrichosis mimicking the alternative route of transmission is essential to understanding disease pathogenesis and the development of novel therapeutic strategies. To explore the impact of horizontal transmission in animals (e.g., cat-cat) and zoonotic transmission on Sporothrix fitness, the left hind footpads of BALB/c mice were inoculated with 5×106 yeasts (n = 11 S. brasiliensis, n = 2 S. schenckii, or n = 1 S. globosa). Twenty days post-infection, our model reproduced both the pathophysiology and symptomology of sporotrichosis with suppurating subcutaneous nodules that progressed proximally along lymphatic channels. Across the main pathogenic members of the S. schenckii clade, S. brasiliensis was usually more virulent than S. schenckii and S. globosa. However, the virulence in S. brasiliensis was strain-dependent, and we demonstrated that highly virulent isolates disseminate from the left hind footpad to the liver, spleen, kidneys, lungs, heart, and brain of infected animals, inducing significant and chronic weight loss (losing up to 15% of their body weight). The weight loss correlated with host death between 2 and 16 weeks post-infection. Histopathological features included necrosis, suppurative inflammation, and polymorphonuclear and mononuclear inflammatory infiltrates. Immunoblot using specific antisera and homologous exoantigen investigated the humoral response. Antigenic profiles were isolate-specific, supporting the hypothesis that different Sporothrix species can elicit a heterogeneous humoral response over time, but cross reaction was observed

Comet assay on tetraploid yeast cells

DEFF Research Database (Denmark)

Rank, Jette; Syberg, Kristian; Jensen, Klara

2009-01-01

Tetraploid yeast cells (Saccharomyces cerevisiae) were used in the comet assay with the intention of developing a new, fast and easy assay for detecting environmental genotoxic agents without using higher organisms. Two DNA-damaging chemicals, H2O2 and acrylamide, together with wastewater from...... three municipal treatment plants were tested for their effect on the yeast-cell DNA. The main problem with using yeast in the comet assay is the necessity to degrade the cell wall. This was achieved by using Zymolase 100 T twice during the procedure, since Zymolase 20 T did not open the cell wall....... Analytical problems that arose due to the small amount of DNA in the yeast nuclei in haploid and diploid cells, which contain 13 Mbp and 26 Mbp DNA per cell, respectively, were solved by using tetraploid yeast cells (52 Mbp) instead. DNA damage was shown after exposure to H2O2 and acrylamide. The lowest dose...

Nocardia brasiliensis induces an immunosuppressive microenvironment that favors chronic infection in BALB/c mice.

Science.gov (United States)

Rosas-Taraco, Adrian G; Perez-Liñan, Amira R; Bocanegra-Ibarias, Paola; Perez-Rivera, Luz I; Salinas-Carmona, Mario C

2012-07-01

Nocardia brasiliensis is an intracellular microorganism and the most common etiologic agent of actinomycetoma in the Americas. Several intracellular pathogens induce an immunosuppressive microenvironment through increases in CD4+ Foxp3+ regulatory T cells (Treg), thus downregulating other T-cell subpopulations and assuring survival in the host. In this study, we determined whether N. brasiliensis modulates T-lymphocyte responses and their related cytokine profiles in a murine experimental model. We also examined the relationship between N. brasiliensis immunomodulation and pathogenesis and bacterial survival. In early infection, Th17/Tc17 cells were increased at day 3 (P 1 log) was also observed (P brasiliensis modulates the immune system to induce an immunosuppressive microenvironment that benefits its survival during the chronic stage of infection.

Revalidation and redescription of Triatoma brasiliensis macromelasoma Galvão, 1956 and an identification key for the Triatoma brasiliensis complex (Hemiptera: Reduviidae: Triatominae

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Jane Costa

2013-09-01

Full Text Available Triatoma brasiliensis macromelasoma is revalidated based on the results of previous multidisciplinary studies on the Triatoma brasiliensis complex, consisting of crossing experiments and morphological, biological, ecological and molecular analyses. These taxonomic tools showed the closest relationship between T. b. macromelasoma and Triatoma brasiliensis brasiliensis. T. b. macromelasoma is redescribed based on specimens collected in the type locality and specimens from a F1 colony. The complex now comprises T. b. brasiliensis, T. b. macromelasoma, Triatoma melanica, Triatoma juazeirensis and Triatoma sherlocki. An identification key for all members of the complex is presented. This detailed comparative study of the morphological features of T. b. macromelasoma and the remaining members of the complex corroborates results from multidisciplinary analyses, suggesting that the subspecific status is applicable. This subspecies can be distinguished by the following combination of features: a pronotum with 1+1 narrow brownish-yellow stripes on the submedian carinae, not attaining its apex, hemelytra with membrane cells darkened on the central portion and legs with an incomplete brownish-yellow ring on the apical half of the femora. Because the T. brasiliensis complex is of distinct epidemiological importance throughout its geographic distribution, a precise identification of its five members is important for monitoring and controlling actions against Chagas disease transmission.

∆24-sterol methyltransferase plays an important role in the growth and development of Sporothrix schenckii and Sporothrix brasiliensis

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Luana Pereira Borba-Santos

2016-03-01

Full Text Available Inhibition of ∆24-sterol methyltransferase (24-SMT in Sporothrix schenckii sensu stricto and Sporothrix brasiliensis was investigated in vitro. The effects on fungal growth and sterol composition of the 24-SMT inhibitor 22-hydrazone-imidazolin-2-yl-chol-5-ene-3-ol (H3 were compared to those of itraconazole. MIC and MFC analysis showed that H3 was more effective than itraconazole against both species in both their filamentous and yeast forms. H3 showed fungistatic activity in a time-kill assay, with inhibitory activity stronger than that of itraconazole. GC analysis of cell sterol composition showed that sterols present in control cells (ergosterol and precursors were completely replaced by 14-methylated sterols after H3 exposure. Itraconazole only partially inhibited ergosterol synthesis but completely arrested synthesis of other sterols found in control cells, promoting accumulation of nine 14-methyl sterols. Based on these results, we propose a schematic model of sterol biosynthesis pathways in S. schenckii and S. brasiliensis. Effects on cell morphology due to 24-SMT inhibition by H3 as analyzed by SEM and TEM included irregular cell shape, reduced cytoplasmic electron-density, and reduced thickness of the microfibrillar cell wall layer. Moreover, 24-SMT inhibition by H3 promoted mitochondrial disturbance, as demonstrated by alterations in MitoTracker® Red CMXRos fluorescence intensity evaluated by flow cytometry. When used in conjunction with itraconazole, H3 enhanced the effectiveness of itraconazole against all tested strains, reducing at least half (or more the MIC values of itraconazole. In addition, cytotoxicity assays revealed that H3 was more selective towards these fungi than was itraconazole. Thus, 24-SMT inhibition by H3 was an effective antifungal strategy against S. schenckii and S. brasiliensis. Inhibition of the methylation reaction catalyzed by 24-SMT has a strong antiproliferative effect via disruption of

Δ(24)-Sterol Methyltransferase Plays an Important Role in the Growth and Development of Sporothrix schenckii and Sporothrix brasiliensis.

Science.gov (United States)

Borba-Santos, Luana P; Visbal, Gonzalo; Gagini, Thalita; Rodrigues, Anderson M; de Camargo, Zoilo P; Lopes-Bezerra, Leila M; Ishida, Kelly; de Souza, Wanderley; Rozental, Sonia

2016-01-01

Inhibition of Δ(24)-sterol methyltransferase (24-SMT) in Sporothrix schenckii sensu stricto and Sporothrix brasiliensis was investigated in vitro. The effects on fungal growth and sterol composition of the 24-SMT inhibitor 22-hydrazone-imidazolin-2-yl-chol-5-ene-3β-ol (H3) were compared to those of itraconazole. MIC and MFC analysis showed that H3 was more effective than itraconazole against both species in both their filamentous and yeast forms. H3 showed fungistatic activity in a time-kill assay, with inhibitory activity stronger than that of itraconazole. GC analysis of cell sterol composition showed that sterols present in control cells (ergosterol and precursors) were completely replaced by 14α-methylated sterols after H3 exposure. Itraconazole only partially inhibited ergosterol synthesis but completely arrested synthesis of other sterols found in control cells, promoting accumulation of nine 14α-methyl sterols. Based on these results, we propose a schematic model of sterol biosynthesis pathways in S. schenckii and S. brasiliensis. Effects on cell morphology due to 24-SMT inhibition by H3 as analyzed by SEM and TEM included irregular cell shape, reduced cytoplasmic electron-density, and reduced thickness of the microfibrillar cell wall layer. Moreover, 24-SMT inhibition by H3 promoted mitochondrial disturbance, as demonstrated by alterations in MitoTracker(®) Red CMXRos fluorescence intensity evaluated by flow cytometry. When used in conjunction with itraconazole, H3 enhanced the effectiveness of itraconazole against all tested strains, reducing at least half (or more) the MIC values of itraconazole. In addition, cytotoxicity assays revealed that H3 was more selective toward these fungi than was itraconazole. Thus, 24-SMT inhibition by H3 was an effective antifungal strategy against S. schenckii and S. brasiliensis. Inhibition of the methylation reaction catalyzed by 24-SMT has a strong antiproliferative effect via disruption of ergosterol homeostasis

Δ24-Sterol Methyltransferase Plays an Important Role in the Growth and Development of Sporothrix schenckii and Sporothrix brasiliensis

Science.gov (United States)

Borba-Santos, Luana P.; Visbal, Gonzalo; Gagini, Thalita; Rodrigues, Anderson M.; de Camargo, Zoilo P.; Lopes-Bezerra, Leila M.; Ishida, Kelly; de Souza, Wanderley; Rozental, Sonia

2016-01-01

Inhibition of Δ24-sterol methyltransferase (24-SMT) in Sporothrix schenckii sensu stricto and Sporothrix brasiliensis was investigated in vitro. The effects on fungal growth and sterol composition of the 24-SMT inhibitor 22-hydrazone-imidazolin-2-yl-chol-5-ene-3β-ol (H3) were compared to those of itraconazole. MIC and MFC analysis showed that H3 was more effective than itraconazole against both species in both their filamentous and yeast forms. H3 showed fungistatic activity in a time-kill assay, with inhibitory activity stronger than that of itraconazole. GC analysis of cell sterol composition showed that sterols present in control cells (ergosterol and precursors) were completely replaced by 14α-methylated sterols after H3 exposure. Itraconazole only partially inhibited ergosterol synthesis but completely arrested synthesis of other sterols found in control cells, promoting accumulation of nine 14α-methyl sterols. Based on these results, we propose a schematic model of sterol biosynthesis pathways in S. schenckii and S. brasiliensis. Effects on cell morphology due to 24-SMT inhibition by H3 as analyzed by SEM and TEM included irregular cell shape, reduced cytoplasmic electron-density, and reduced thickness of the microfibrillar cell wall layer. Moreover, 24-SMT inhibition by H3 promoted mitochondrial disturbance, as demonstrated by alterations in MitoTracker® Red CMXRos fluorescence intensity evaluated by flow cytometry. When used in conjunction with itraconazole, H3 enhanced the effectiveness of itraconazole against all tested strains, reducing at least half (or more) the MIC values of itraconazole. In addition, cytotoxicity assays revealed that H3 was more selective toward these fungi than was itraconazole. Thus, 24-SMT inhibition by H3 was an effective antifungal strategy against S. schenckii and S. brasiliensis. Inhibition of the methylation reaction catalyzed by 24-SMT has a strong antiproliferative effect via disruption of ergosterol homeostasis

Matrix metalloproteinases with gelatinolytic activity induced by Paracoccidioides brasiliensis infection

Science.gov (United States)

Nishikaku, Angela Satie; Ribeiro, Luciana Cristina; Molina, Raphael Fagnani Sanchez; Albe, Bernardo Paulo; Cunha, Cláudia da Silva; Burger, Eva

2009-01-01

Matrix metalloproteinases (MMPs) modulate extracellular matrix turnover, inflammation and immunity. We studied MMP-9 and MMP-2 in experimental paracoccidioidomycosis. At 15 and 120 days after infection (DAI) with virulent Paracoccidioides brasiliensis, MMP-9 was positive by immunohistochemistry in multinucleated giant cells, in mononuclear cells with macrophage and lymphocyte morphologies and also in fungal cells in the lesions of susceptible and resistant mice. Using gelatin zymography, pro- and active MMP-9 and active MMP-2 were detected in all infected mice, but not in controls. Gelatinolytic activity was not observed in P. brasiliensis extracts. Semiquantitative analysis of gelatinolytic activities revealed weak or absent MMP-2 and strong MMP-9 activity in both mouse strains at 15 DAI, declining at 120 DAI. Avirulent P. brasiliensis-infected mice had residual lesions with MMP-9-positive pseudoxantomatous macrophages, but no gelatinase activity at 120 DAI. Our findings demonstrate the induction of MMPs, particularly MMP-9, in experimental paracoccidioidomycosis, suggesting a possible influence in the pattern of granulomas and in fungal dissemination. PMID:19765107

Radiometric detection of metabolic activity of Paracoccidiodes brasiliensis and its susceptibility to amphotericin B and Diethylstilbestrol

International Nuclear Information System (INIS)

Camargo, E.E.; Sato, M.K.; Del Negro, G.M.B.; Lacaz, C.S.

1987-01-01

A radiometric assay system has been applied to study the metabolic activity and the effect of drugs (amphotericin B and diethylstilbestrol) on the fungus Paracoccidiodes brasiliensis ''in vitro''. The Y form of the yeast, grown in liquid Sabouraud medium was inoculated into sterile reaction vials containing the 6B aerobic medium along with 2.0μCi of 14 C-substrates. (M.A.C.) [pt

Yeast cell wall chitin reduces wine haze formation.

Science.gov (United States)

Ndlovu, Thulile; Divol, Benoit; Bauer, Florian F

2018-04-27

Protein haze formation in bottled wines is a significant concern for the global wine industry and wine clarification before bottling is therefore a common but expensive practice. Previous studies have shown that wine yeast strains can reduce haze formation through the secretion of certain mannoproteins, but it has been suggested that other yeast-dependent haze protective mechanisms exist. On the other hand, addition of chitin has been shown to reduce haze formation, likely because grape chitinases have been shown to be the major contributors to haze. In this study, Chardonnay grape must fermented by various yeast strains resulted in wines with different protein haze levels indicating differences in haze protective capacities of the strains. The cell wall chitin levels of these strains were determined, and a strong correlation between cell wall chitin levels and haze protection capability was observed. To further evaluate the mechanism of haze protection, Escherichia coli -produced GFP-tagged grape chitinase was shown to bind efficiently to yeast cell walls in a cell wall chitin concentration-dependent manner, while commercial chitinase was removed from synthetic wine in quantities also correlated with the cell wall chitin levels of the strains. Our findings suggest a new mechanism of reducing wine haze, and propose a strategy for optimizing wine yeast strains to improve wine clarification. Importance In this study, we establish a new mechanism by which wine yeast strains can impact on the protein haze formation of wines, and demonstrate that yeast cell wall chitin binds grape chitinase in a chitin-concentration dependent manner. We also show that yeast can remove this haze-forming protein from wine. Chitin has in the past been shown to efficiently reduce wine haze formation when added to the wine in high concentration as a clarifying agent. Our data suggest that the selection of yeast strains with high levels of cell wall chitin can reduce protein haze. We also

Development of CD4 T cell dependent immunity against N. brasiliensis infection

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Marina eHarvie

2013-03-01

Full Text Available Of all the microbial infections relevant to mammals the relationship between parasitic worms and what constitutes and regulates a host protective immune response is perhaps the most complex and evolved. Nippostrongylus brasiliensis is a tissue migrating parasitic roundworm of rodents that exemplifies many of the salient features of parasitic worm infection, including parasite development through sequential larval stages as it migrates through specific tissue sites. Immune competent hosts respond to infection by N. brasiliensis with a rapid and selective development of a profound Th2 immune response that appears able to confer life long protective immunity against reinfection. This review details how the lung can be the site of migrating nematode immune killing and the gut a site of rapid immune mediated clearance of worms. Furthermore it appears that N. brasiliensis induced responses in the lung are sufficient for conferring immunity in lung and gut while infection of the gut only confers immunity in the gut. This review also covers the role of IL-4, STAT6 and the innate cytokines IL-25, IL-33 and TSLP in the generation of CD4-mediated immunity against N. brasiliensis reinfection and discusses what cytokines might be involved in mediated killing or expulsion of helminth parasites.

Primary Nocardia brasiliensis of the eyelid.

Science.gov (United States)

Brannan, Paul A; Kersten, Robert C; Hudak, Donald T; Anderson, Heidi K; Kulwin, Dwight R

2004-09-01

To report a rare case of lymphocutaneous Nocardia brasiliensis originating in the eyelid. Observational case report. The clinical presentation, workup, and treatment of a case of lymphocutaneous Nocardia brasiliensis originating in the eyelid are presented. The patient presented with a preseptal cellulitis from an abrasion of the eyelid that progressed to submandibular lymph node suppuration. Culture was performed, and a diagnosis of lymphocutaneous Nocardia brasiliensis was made. Nocardia brasiliensis may cause a lymphocutaneous infection of the face and must be considered in the differential diagnosis of preseptal cellulitis.

Dielectric modelling of cell division for budding and fission yeast

International Nuclear Information System (INIS)

Asami, Koji; Sekine, Katsuhisa

2007-01-01

The frequency dependence of complex permittivity or the dielectric spectrum of a system including a cell in cell division has been simulated by a numerical technique based on the three-dimensional finite difference method. Two different types of cell division characteristic of budding and fission yeast were examined. The yeast cells are both regarded as a body of rotation, and thus have anisotropic polarization, i.e. the effective permittivity of the cell depends on the orientation of the cell to the direction of an applied electric field. In the perpendicular orientation, where the rotational axis of the cell is perpendicular to the electric field direction, the dielectric spectra for both yeast cells included one dielectric relaxation and its intensity depended on the cell volume. In the parallel orientation, on the other hand, two dielectric relaxations appeared with bud growth for budding yeast and with septum formation for fission yeast. The low-frequency relaxation was shifted to a lower frequency region by narrowing the neck between the bud and the mother cell for budding yeast and by increasing the degree of septum formation for fission yeast. After cell separation, the low-frequency relaxation disappeared. The simulations well interpreted the oscillation of the relative permittivity of culture broth found for synchronous cell growth of budding yeast

Dendritic Cells Primed with Paracoccidioides brasiliensis Peptide P10 Are Therapeutic in Immunosuppressed Mice with Paracoccidioidomycosis

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Leandro B. R. Silva

2017-06-01

Full Text Available Paracoccidioidomycosis (PCM is an endemic systemic mycosis in Latin America, with the highest prevalence in Brazil, Colombia, and Venezuela. Fungi of the Paracoccidioides genus are etiologic agents of the disease. The 15 amino acid peptide P10 is derived from gp43, the main diagnostic antigen of Paracoccidioides brasiliensis. We previously reported that P10-pulsed dendritic cells (DCs induce a protective response against P. brasiliensis. Presently, dexamethasone-treated BALB/c mice were intratracheally infected with P. brasiliensis Pb18 to establish the therapeutic efficacy of P10-pulsed DCs. Immunosuppressed and infected animals that received DCs had a reduction in their fungal burden, and this result was most pronounced in mice receiving DCs primed with P10. The efficacy of therapeutic DCs was significantly augmented by concomitant treatment with trimethoprim-sulfamethoxazole. Additionally, primed-DCs with or without the antifungal drug induced a beneficial Th1-biased immune response and significantly reduced tissue damage. In conclusion, these studies with immunocompromised mice demonstrate that P10-pulsed DCs with or without concomitant antifungal drugs are potently effective in combating invasive PCM. These findings support further translational studies to validate the use of P10-primed DCs for PCM in immunocompetent and immunosuppressed hosts.

Effect of salt hyperosmotic stress on yeast cell viability

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Logothetis Stelios

2007-01-01

Full Text Available During fermentation for ethanol production, yeasts are subjected to different kinds of physico-chemical stresses such as: initially high sugar concentration and low temperature; and later, increased ethanol concentrations. Such conditions trigger a series of biological responses in an effort to maintain cell cycle progress and yeast cell viability. Regarding osmostress, many studies have been focused on transcriptional activation and gene expression in laboratory strains of Saccharomyces cerevisiae. The overall aim of this present work was to further our understanding of wine yeast performance during fermentations under osmotic stress conditions. Specifically, the research work focused on the evaluation of NaCl-induced stress responses of an industrial wine yeast strain S. cerevisiae (VIN 13, particularly with regard to yeast cell growth and viability. The hypothesis was that osmostress conditions energized specific genes to enable yeast cells to survive under stressful conditions. Experiments were designed by pretreating cells with different sodium chloride concentrations (NaCl: 4%, 6% and 10% w/v growing in defined media containing D-glucose and evaluating the impact of this on yeast growth and viability. Subsequent fermentation cycles took place with increasing concentrations of D-glucose (20%, 30%, 40% w/v using salt-adapted cells as inocula. We present evidence that osmostress induced by mild salt pre-treatments resulted in beneficial influences on both cell viability and fermentation performance of an industrial wine yeast strain.

Guidelines and recommendations on yeast cell death nomenclature

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Didac Carmona-Gutierrez

2018-01-01

Full Text Available Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research.

Guidelines and recommendations on yeast cell death nomenclature

Science.gov (United States)

Carmona-Gutierrez, Didac; Bauer, Maria Anna; Zimmermann, Andreas; Aguilera, Andrés; Austriaco, Nicanor; Ayscough, Kathryn; Balzan, Rena; Bar-Nun, Shoshana; Barrientos, Antonio; Belenky, Peter; Blondel, Marc; Braun, Ralf J.; Breitenbach, Michael; Burhans, William C.; Büttner, Sabrina; Cavalieri, Duccio; Chang, Michael; Cooper, Katrina F.; Côrte-Real, Manuela; Costa, Vítor; Cullin, Christophe; Dawes, Ian; Dengjel, Jörn; Dickman, Martin B.; Eisenberg, Tobias; Fahrenkrog, Birthe; Fasel, Nicolas; Fröhlich, Kai-Uwe; Gargouri, Ali; Giannattasio, Sergio; Goffrini, Paola; Gourlay, Campbell W.; Grant, Chris M.; Greenwood, Michael T.; Guaragnella, Nicoletta; Heger, Thomas; Heinisch, Jürgen; Herker, Eva; Herrmann, Johannes M.; Hofer, Sebastian; Jiménez-Ruiz, Antonio; Jungwirth, Helmut; Kainz, Katharina; Kontoyiannis, Dimitrios P.; Ludovico, Paula; Manon, Stéphen; Martegani, Enzo; Mazzoni, Cristina; Megeney, Lynn A.; Meisinger, Chris; Nielsen, Jens; Nyström, Thomas; Osiewacz, Heinz D.; Outeiro, Tiago F.; Park, Hay-Oak; Pendl, Tobias; Petranovic, Dina; Picot, Stephane; Polčic, Peter; Powers, Ted; Ramsdale, Mark; Rinnerthaler, Mark; Rockenfeller, Patrick; Ruckenstuhl, Christoph; Schaffrath, Raffael; Segovia, Maria; Severin, Fedor F.; Sharon, Amir; Sigrist, Stephan J.; Sommer-Ruck, Cornelia; Sousa, Maria João; Thevelein, Johan M.; Thevissen, Karin; Titorenko, Vladimir; Toledano, Michel B.; Tuite, Mick; Vögtle, F.-Nora; Westermann, Benedikt; Winderickx, Joris; Wissing, Silke; Wölfl, Stefan; Zhang, Zhaojie J.; Zhao, Richard Y.; Zhou, Bing; Galluzzi, Lorenzo; Kroemer, Guido; Madeo, Frank

2018-01-01

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research. PMID:29354647

Lipid raft involvement in yeast cell growth and death

Energy Technology Data Exchange (ETDEWEB)

Mollinedo, Faustino, E-mail: fmollin@usal.es [Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas - Universidad de Salamanca, Salamanca (Spain)

2012-10-10

The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na{sup +}, K{sup +}, and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

Lipid raft involvement in yeast cell growth and death

International Nuclear Information System (INIS)

Mollinedo, Faustino

2012-01-01

The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na + , K + , and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

Nonlinear Dielectric Properties of Yeast Cells Cultured in Different Environmental Conditions

Science.gov (United States)

Kawanishi, Gomon; Fukuda, Naoki; Muraji, Masafumi

The harmonics of the electric current through yeast suspensions, the nonlinear dielectric properties of yeast cells, have particular patterns according to the biological activity of the cells and the measurement of these patterns is a technique for determining the activity of living cells. The concentration of glucose and oxygen in yeast culture medium influences the manifestation of fermentation or respiration of yeast cells. Measurements were made with yeast cells (Saccharomyces cerevisiae) cultured aerobically and anaerobically in sufficient glucose concentration, aerobic fermentation and anaerobic fermentation, and aerobically in limited glucose concentration, respiration. The results showed that the harmonics were barely apparent for yeast cells in aerobic fermentation and respiratory; however, cells in the anaerobic fermentation displayed substantial third and fifth harmonics. We can say that environmental condition affects the yeast cells' nonlinear properties, from another viewpoint, the measurements of the nonlinear properties are available to determine the activity of yeast cells adjusted to the conditions of their cultivation.

Guidelines and recommendations on yeast cell death nomenclature

OpenAIRE

Carmona-Gutierrez, Didac; Bauer, Maria Anna; Zimmermann, Andreas; Aguilera, Andres; Austriaco, Nicanor; Sigrist, Stephan J.

2018-01-01

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of mor...

Yeast cells proliferation on various strong static magnetic fields and temperatures

International Nuclear Information System (INIS)

Otabe, E S; Kuroki, S; Nikawa, J; Matsumoto, Y; Ooba, T; Kiso, K; Hayashi, H

2009-01-01

The effect of strong magnetic fields on activities of yeast cells were investigated. Experimental yeast cells were cultured in 5 ml of YPD(Yeast extract Peptone Dextrose) for the number density of yeast cells of 5.0 ±0.2 x 10 6 /ml with various temperatures and magnetic fields up to 10 T. Since the yeast cells were placed in the center of the superconducting magnet, the effect of magnetic force due to the diamagnetism and magnetic gradient was negligibly small. The yeast suspension was opened to air and cultured in shaking condition. The number of yeast cells in the yeast suspension was counted by a counting plate with an optical microscope, and the time dependence of the number density of yeast cells was measured. The time dependence of the number density of yeast cells, ρ, of initial part is analyzed in terms of Malthus equation as given by ρ = ρo exp(kt), where k is the growth coefficient. It is found that, the growth coefficient under the magnetic field is suppressed compared with the control. The growth coefficient decreasing as increasing magnetic field and is saturated at about 5 T. On the other hand, it is found that the suppression of growth of yeast cells by the magnetic field is diminished at high temperatures.

Detection of Multiple Budding Yeast Cells and a Partial Sequence of 43-kDa Glycoprotein Coding Gene of Paracoccidioides brasiliensis from a Case of Lacaziosis in a Female Pacific White-Sided Dolphin (Lagenorhynchus obliquidens).

Science.gov (United States)

Minakawa, Tomoko; Ueda, Keiichi; Tanaka, Miyuu; Tanaka, Natsuki; Kuwamura, Mitsuru; Izawa, Takeshi; Konno, Toshihiro; Yamate, Jyoji; Itano, Eiko Nakagawa; Sano, Ayako; Wada, Shinpei

2016-08-01

Lacaziosis, formerly called as lobomycosis, is a zoonotic mycosis, caused by Lacazia loboi, found in humans and dolphins, and is endemic in the countries on the Atlantic Ocean, Indian Ocean and Pacific Ocean of Japanese coast. Susceptible Cetacean species include the bottlenose dolphin (Tursiops truncatus), the Indian Ocean bottlenose dolphin (T. aduncus), and the estuarine dolphin (Sotalia guianensis); however, no cases have been recorded in other Cetacean species. We diagnosed a case of Lacaziosis in a Pacific white-sided dolphin (Lagenorhynchus obliquidens) nursing in an aquarium in Japan. The dolphin was a female estimated to be more than 14 years old at the end of June 2015 and was captured in a coast of Japan Sea in 2001. Multiple, lobose, and solid granulomatous lesions with or without ulcers appeared on her jaw, back, flipper and fluke skin, in July 2014. The granulomatous skin lesions from the present case were similar to those of our previous cases. Multiple budding and chains of round yeast cells were detected in the biopsied samples. The partial sequence of 43-kDa glycoprotein coding gene confirmed by a nested PCR and sequencing, which revealed a different genotype from both Amazonian and Japanese lacaziosis in bottlenose dolphins, and was 99 % identical to those derived from Paracoccidioides brasiliensis; a sister fungal species to L. loboi. This is the first case of lacaziosis in Pacific white-sided dolphin.

Oxidative Stress and Programmed Cell Death in Yeast

International Nuclear Information System (INIS)

Farrugia, Gianluca; Balzan, Rena

2012-01-01

Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed.

Mitochondrial fission proteins regulate programmed cell death in yeast.

Science.gov (United States)

Fannjiang, Yihru; Cheng, Wen-Chih; Lee, Sarah J; Qi, Bing; Pevsner, Jonathan; McCaffery, J Michael; Hill, R Blake; Basañez, Gorka; Hardwick, J Marie

2004-11-15

The possibility that single-cell organisms undergo programmed cell death has been questioned in part because they lack several key components of the mammalian cell death machinery. However, yeast encode a homolog of human Drp1, a mitochondrial fission protein that was shown previously to promote mammalian cell death and the excessive mitochondrial fragmentation characteristic of apoptotic mammalian cells. In support of a primordial origin of programmed cell death involving mitochondria, we found that the Saccharomyces cerevisiae homolog of human Drp1, Dnm1, promotes mitochondrial fragmentation/degradation and cell death following treatment with several death stimuli. Two Dnm1-interacting factors also regulate yeast cell death. The WD40 repeat protein Mdv1/Net2 promotes cell death, consistent with its role in mitochondrial fission. In contrast to its fission function in healthy cells, Fis1 unexpectedly inhibits Dnm1-mediated mitochondrial fission and cysteine protease-dependent cell death in yeast. Furthermore, the ability of yeast Fis1 to inhibit mitochondrial fission and cell death can be functionally replaced by human Bcl-2 and Bcl-xL. Together, these findings indicate that yeast and mammalian cells have a conserved programmed death pathway regulated by a common molecular component, Drp1/Dnm1, that is inhibited by a Bcl-2-like function.

Interactions of Condensed Tannins with Saccharomyces cerevisiae Yeast Cells and Cell Walls: Tannin Location by Microscopy.

Science.gov (United States)

Mekoue Nguela, Julie; Vernhet, Aude; Sieczkowski, Nathalie; Brillouet, Jean-Marc

2015-09-02

Interactions between grape tannins/red wine polyphenols and yeast cells/cell walls was previously studied within the framework of red wine aging and the use of yeast-derived products as an alternative to aging on lees. Results evidenced a quite different behavior between whole cells (biomass grown to elaborate yeast-derived products, inactivated yeast, and yeast inactivated after autolysis) and yeast cell walls (obtained from mechanical disruption of the biomass). Briefly, whole cells exhibited a high capacity to irreversibly adsorb grape and wine tannins, whereas only weak interactions were observed for cell walls. This last point was quite unexpected considering the literature and called into question the real role of cell walls in yeasts' ability to fix tannins. In the present work, tannin location after interactions between grape and wine tannins and yeast cells and cell walls was studied by means of transmission electron microscopy, light epifluorescence, and confocal microscopy. Microscopy observations evidenced that if tannins interact with cell walls, and especially cell wall mannoproteins, they also diffuse freely through the walls of dead cells to interact with their plasma membrane and cytoplasmic components.

Transcriptional Waves in the Yeast Cell Cycle

OpenAIRE

Oliva, Anna; Rosebrock, Adam; Ferrezuelo, Francisco; Pyne, Saumyadipta; Chen, Haiying; Skiena, Steve; Futcher, Bruce; Leatherwood, Janet

2005-01-01

Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillat...

Synergistic reduction of toluylene blue induced by acetaldehyde and menadione in yeast cell suspension: Application to determination of yeast cell activity

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Shiro Yamashoji

2017-03-01

Full Text Available Membrane permeant acetaldehyde and menadione induced the synergistic reduction of toluylene blue (TB acting as non-membrane permeant redox indicator in yeast cell suspension. NADH and acetaldehyde also induced the synergistic TB reduction in permeabilized yeast cells and phosphate buffer, but menadione had no ability to promote TB reduction. The pre-incubation of acetaldehyde inhibited the above synergistic reduction of TB in intact and permeabilized yeast cell suspension. The pre-incubation of acetaldehyde might promote NADH oxidation by alcohol dehydrogenase, because acetaldehyde decreased the intracellular NAD(PH concentration. The above facts indicate that the synergistic reduction of TB is controlled by the order of addition of menadione and acetaldehyde. The synergistic reduction of TB by menadione and acetaldehyde was proportional to viable yeast cell number from 104 to 2×106 cells/ml, and this assay was applicable to cytotoxicity test. The time required for the above assay was only 2 min.

Exploring potential virulence regulators in Paracoccidioides brasiliensis isolates of varying virulence through quantitative proteomics.

Science.gov (United States)

Castilho, Daniele G; Chaves, Alison F A; Xander, Patricia; Zelanis, André; Kitano, Eduardo S; Serrano, Solange M T; Tashima, Alexandre K; Batista, Wagner L

2014-10-03

Few virulence factors have been identified for Paracoccidioides brasiliensis, the agent of paracoccidioidomycosis. In this study, we quantitatively evaluated the protein composition of P. brasiliensis in the yeast phase using minimal and rich media to obtain a better understanding of its virulence and to gain new insights into pathogen adaptation strategies. This analysis was performed on two isolates of the Pb18 strain showing distinct infection profiles in B10.A mice. Using liquid chromatography/tandem mass spectrometry (LC-MS/MS) analysis, we identified and quantified 316 proteins in minimal medium, 29 of which were overexpressed in virulent Pb18. In rich medium, 29 out of 295 proteins were overexpressed in the virulent fungus. Three proteins were found to be up-regulated in both media, suggesting the potential roles of these proteins in virulence regulation in P. brasiliensis. Moreover, genes up-regulated in virulent Pb18 showed an increase in its expression after the recovery of virulence of attenuated Pb18. Proteins up-regulated in both isolates were grouped according to their functional categories. Virulent Pb18 undergoes metabolic reorganization and increased expression of proteins involved in fermentative respiration. This approach allowed us to identify potential virulence regulators and provided a foundation for achieving a molecular understanding of how Paracoccidioides modulates the host-pathogen interaction to its advantage.

Identification of Paracoccidioides brasiliensis by gold nanoprobes

Science.gov (United States)

Martins, Jaciara F. S.; Castilho, Maiara L.; Cardoso, Maria A. G.; Carreiro, Andrea P.; Martin, Airton A.; Raniero, Leandro

2012-01-01

Paracoccidioides brasiliensis (P. brasiliensis) is a thermal dimorphic fungus and causal agent of paracoccidioidomycosis. Epidemiological data shows that it is mainly concentrated in Central and South America countries, with most registered cases in Colombia, Brazil, and Venezuela. The histopathological similarity with others fungal infection makes the diagnosis of P. brasiliensis more complicated. Therefore, the aim of this work was to find a positive and negative test for P. brasiliensis using gold nanoprobes as a new tool for P. brasiliensis detection. Gold nanoparticles were synthesized by reduction of gold chloride with sodium citrate. The results of this procedure is a wine-red solution with a maximum absorption in the range of ~520-530nm. A specific P. brasiliensis sequence of oligonucleotide was bonded to the nanoparticles, which maintained the wine-red color. The color changes from red to blue for negative diagnostic and is unchanged for a positive test. The H-bond interaction of DNA with the complementary DNA keeps strands together and forms double helical structure, maintaining the colloid stability. However, for non-complimentary DNA sequence the nanoprobes merge into a cluster, changing the light absorption.

Guidelines and recommendations on yeast cell death nomenclature

NARCIS (Netherlands)

Carmona-Gutierrez, Didac; Bauer, Maria Anna; Zimmermann, Andreas; Aguilera, Andrés; Austriaco, Nicanor; Ayscough, Kathryn; Balzan, Rena; Bar-Nun, Shoshana; Barrientos, Antonio; Belenky, Peter; Blondel, Marc; Braun, Ralf J; Breitenbach, Michael; Burhans, William C; Büttner, Sabrina; Cavalieri, Duccio; Chang, Michael; Cooper, Katrina F; Côrte-Real, Manuela; Costa, Vítor; Cullin, Christophe; Dawes, Ian; Dengjel, Jörn; Dickman, Martin B; Eisenberg, Tobias; Fahrenkrog, Birthe; Fasel, Nicolas; Fröhlich, Kai-Uwe; Gargouri, Ali; Giannattasio, Sergio; Goffrini, Paola; Gourlay, Campbell W; Grant, Chris M; Greenwood, Michael T; Guaragnella, Nicoletta; Heger, Thomas; Heinisch, Jürgen; Herker, Eva; Herrmann, Johannes M; Hofer, Sebastian; Jiménez-Ruiz, Antonio; Jungwirth, Helmut; Kainz, Katharina; Kontoyiannis, Dimitrios P; Ludovico, Paula; Manon, Stéphen; Martegani, Enzo; Mazzoni, Cristina; Megeney, Lynn A; Meisinger, Chris; Nielsen, Jens; Nyström, Thomas; Osiewacz, Heinz D; Outeiro, Tiago F; Park, Hay-Oak; Pendl, Tobias; Petranovic, Dina; Picot, Stephane; Polčic, Peter; Powers, Ted; Ramsdale, Mark; Rinnerthaler, Mark; Rockenfeller, Patrick; Ruckenstuhl, Christoph; Schaffrath, Raffael; Segovia, Maria; Severin, Fedor F; Sharon, Amir; Sigrist, Stephan J; Sommer-Ruck, Cornelia; Sousa, Maria João; Thevelein, Johan M; Thevissen, Karin; Titorenko, Vladimir; Toledano, Michel B; Tuite, Mick; Vögtle, F-Nora; Westermann, Benedikt; Winderickx, Joris; Wissing, Silke; Wölfl, Stefan; Zhang, Zhaojie J; Zhao, Richard Y; Zhou, Bing; Galluzzi, Lorenzo; Kroemer, Guido; Madeo, Frank

2018-01-01

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cel-lular demise. However, the investigation of yeast cell death is a relatively young field, and a widely

Sequence and expression analyses of ethylene response factors highly expressed in latex cells from Hevea brasiliensis.

Directory of Open Access Journals (Sweden)

Piyanuch Piyatrakul

Full Text Available 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.

Amphotericin B, alone or followed by itraconazole therapy, is effective in the control of experimental disseminated sporotrichosis by Sporothrix brasiliensis.

Science.gov (United States)

Ishida, Kelly; de Castro, Rafaela Alves; Borba Dos Santos, Luana Pereira; Quintella, Leonardo Pereira; Lopes-Bezerra, Leila M; Rozental, Sonia

2015-01-01

Sporothrix brasiliensis is a highly virulent member of the S. schenckii complex, which is responsible for the emergence of the epidemic sporotrichosis in southeastern Brazil over the last two decades. There are no in vivo studies on the sensitivity of S. brasiliensis to the therapeutic regimens used to treat sporotrichosis. Here, we evaluated the efficacy and safety of antifungal treatments against S. brasiliensis using a murine model of disseminated sporotrichosis. In vitro, S. brasiliensis yeasts were sensitive to low concentrations of amphotericin B-deoxycholate (AMB-d) and itraconazole (ITZ), the latter having greater selectivity toward the fungus. The following treatment regimens were tested in vivo: intravenous AMB-d for 7 days post-infection (p.i.), oral ITZ for up to 30 days p.i., and AMB-d followed by ITZ (AMB-d/ITZ). AMB-d and AMB-d/ITZ led to 100% survival of infected mice at the end of the 45-day experimental period. Although all treatments extended mice survival, only AMB-d and AMB-d/ITZ significantly reduced fungal load in all organs, but AMB-d/ITZ led to a more consistent decrease in overall fungal burden. No treatment increased the levels of serum toxicity biomarkers. Taken together, our results indicate that AMB-d/ITZ is the best therapeutic option for controlling disseminated sporotrichosis caused by S. brasiliensis. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Immobilisation increases yeast cells' resistance to dehydration-rehydration treatment.

Science.gov (United States)

Borovikova, Diana; Rozenfelde, Linda; Pavlovska, Ilona; Rapoport, Alexander

2014-08-20

This study was performed with the goal of revealing if the dehydration procedure used in our new immobilisation method noticeably decreases the viability of yeast cells in immobilised preparations. Various yeasts were used in this research: Saccharomyces cerevisiae cells that were rather sensitive to dehydration and had been aerobically grown in an ethanol-containing medium, a recombinant strain of S. cerevisiae grown in aerobic conditions which were completely non-resistant to dehydration and an anaerobically grown bakers' yeast strain S. cerevisiae, as well as a fairly resistant Pichia pastoris strain. Experiments performed showed that immobilisation of all these strains essentially increased their resistance to a dehydration-rehydration treatment. The increase of cells' viability (compared with control cells dehydrated in similar conditions) was from 30 to 60%. It is concluded that a new immobilisation method, which includes a dehydration stage, does not lead to an essential loss of yeast cell viability. Correspondingly, there is no risk of losing the biotechnological activities of immobilised preparations. The possibility of producing dry, active yeast preparations is shown, for those strains that are very sensitive to dehydration and which can be used in biotechnology in an immobilised form. Finally, the immobilisation approach can be used for the development of efficient methods for the storage of recombinant yeast strains. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption.

Science.gov (United States)

Luo, Ying; Wang, Jianguo; Liu, Bin; Wang, Zhouli; Yuan, Yahong; Yue, Tianli

2015-01-01

The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry.

Immune response to Nocardia brasiliensis extracellular antigens in patients with mycetoma.

Science.gov (United States)

Castro-Matteotti, Bárbara; Vera-Cabrera, Lucio; Ocampo-Candiani, Jorge; Rendón, Adrián; Salinas-Carmona, Mario C; Welsh, Oliverio

2008-03-01

The ability of culture-filtrate proteins to induce a cellular immune response in infected mice and humans was investigated. A crude extract culture filtrate of Nocardia brasiliensis (CFA) and five semi-purified CFA fractions (P1, P2, P3, P4, P5) were used to stimulate BALB/c mice spleen-cell cultures. The animals were divided into three groups: the first group was infected with 1 x 10(7) CFU of N. brasiliensis in the footpad, the second group was immunized with heat-killed bacteria, and the third was injected with sterile saline. IFN-gamma, IL-1alpha, and IL-4 concentrations were determined in culture supernatants. Protein fractions eliciting IFN-gamma production in mice, as well as the CFA, were used to stimulate IFN-gamma production and in vitro cell proliferation assays with peripheral blood mononuclear cells of patients with actinomycetoma by N. brasiliensis, individuals with pulmonary tuberculosis, and healthy controls. In mice, CFA and three of the protein fractions (P3, P4 and P5) induced significant IFN-gamma production in the infected group. In humans, only the CFA-induced IFN-gamma production and cell proliferation in the group of patients with actinomycetoma. There was no stimulation in tuberculosis patients nor healthy controls. These results suggest that some culture-filtrate antigens are recognized by patients with active actinomycetoma and do not cross-react with M. tuberculosis antigens, being therefore potential candidates to develop a diagnostic test.

Correlating yeast cell stress physiology to changes in the cell surface morphology: atomic force microscopic studies.

Science.gov (United States)

Canetta, Elisabetta; Walker, Graeme M; Adya, Ashok K

2006-07-06

Atomic Force Microscopy (AFM) has emerged as a powerful biophysical tool in biotechnology and medicine to investigate the morphological, physical, and mechanical properties of yeasts and other biological systems. However, properties such as, yeasts' response to environmental stresses, metabolic activities of pathogenic yeasts, cell-cell/cell-substrate adhesion, and cell-flocculation have rarely been investigated so far by using biophysical tools. Our recent results obtained by AFM on one strain each of Saccharomyces cerevisiae and Schizosaccharomyces pombe show a clear correlation between the physiology of environmentally stressed yeasts and the changes in their surface morphology. The future directions of the AFM related techniques in relation to yeasts are also discussed.

Nocardia brasiliensis Modulates IFN-gamma, IL-10, and IL-12 cytokine production by macrophages from BALB/c Mice.

Science.gov (United States)

Salinas-Carmona, Mario C; Zúñiga, Juan M; Pérez-Rivera, Luz I; Segoviano-Ramírez, Juan C; Vázquez-Marmolejo, Anna V

2009-05-01

Interferon-gamma (IFN-gamma) is a critical cytokine involved in control of different infections. Actinomycetoma is a chronic infectious disease mainly caused by the bacterium Nocardia brasiliensis, which destroys subcutaneous tissue, including bone. Currently, the mechanism of pathogenesis in N. brasiliensis infection is not known. Here, we demonstrate that N. brasiliensis induced an IFN-gamma response in serum after 24 h of infection, while, in infected tissue, positive cells to IFN-gamma appeared in 2 early peaks: the first was present only 3 h after infection, then transiently decreased; and the second peak appeared 12 h after infection and was independent of interleukin-10. Resident macrophages produced an immediate IFN-gamma response 1 h after in vitro infection, and spleen-positive cells began later. The phase of growth of N. brasiliensis affected cytokine production, and exposure of macrophages to Nocardia opsonized with either polyclonal anti-Nocardia antibodies or anti-P61 monoclonal antibody led to a suppression of cytokine production. Our report provides evidence that N. brasiliensis as an intracellular bacterium modulates macrophage cytokine production, which helps survival of the pathogen. Modulation of these cytokines may contribute to pathogenesis once this bacterium is inside the macrophage.

Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption.

Directory of Open Access Journals (Sweden)

Ying Luo

Full Text Available The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry.

Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

International Nuclear Information System (INIS)

Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

1987-01-01

The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells. (author)

Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

Science.gov (United States)

Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells.

L-lactic acid production by Aspergillus brasiliensis overexpressing the heterologous ldha gene from Rhizopus oryzae.

Science.gov (United States)

Liaud, Nadège; Rosso, Marie-Noëlle; Fabre, Nicolas; Crapart, Sylvaine; Herpoël-Gimbert, Isabelle; Sigoillot, Jean-Claude; Raouche, Sana; Levasseur, Anthony

2015-05-03

Lactic acid is the building block of poly-lactic acid (PLA), a biopolymer that could be set to replace petroleum-based plastics. To make lactic acid production cost-effective, the production process should be carried out at low pH, in low-nutrient media, and with a low-cost carbon source. Yeasts have been engineered to produce high levels of lactic acid at low pH from glucose but not from carbohydrate polymers (e.g. cellulose, hemicellulose, starch). Aspergilli are versatile microbial cell factories able to naturally produce large amounts of organic acids at low pH and to metabolize cheap abundant carbon sources such as plant biomass. However, they have never been used for lactic acid production. To investigate the feasibility of lactic acid production with Aspergillus, the NAD-dependent lactate dehydrogenase (LDH) responsible for lactic acid production by Rhizopus oryzae was produced in Aspergillus brasiliensis BRFM103. Among transformants, the best lactic acid producer, A. brasiliensis BRFM1877, integrated 6 ldhA gene copies, and intracellular LDH activity was 9.2 × 10(-2) U/mg. At a final pH of 1.6, lactic acid titer reached 13.1 g/L (conversion yield: 26%, w/w) at 138 h in glucose-ammonium medium. This extreme pH drop was subsequently prevented by switching nitrogen source from ammonium sulfate to Na-nitrate, leading to a final pH of 3 and a lactic acid titer of 17.7 g/L (conversion yield: 47%, w/w) at 90 h of culture. Final titer was further improved to 32.2 g/L of lactic acid (conversion yield: 44%, w/w) by adding 20 g/L glucose to the culture medium at 96 h. This strain was ultimately able to produce lactic acid from xylose, arabinose, starch and xylan. We obtained the first Aspergillus strains able to produce large amounts of lactic acid by inserting recombinant ldhA genes from R. oryzae into a wild-type A. brasiliensis strain. pH regulation failed to significantly increase lactic acid production, but switching nitrogen source and changing culture feed

Cell wall trapping of autocrine peptides for human G-protein-coupled receptors on the yeast cell surface.

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Jun Ishii

Full Text Available G-protein-coupled receptors (GPCRs regulate a wide variety of physiological processes and are important pharmaceutical targets for drug discovery. Here, we describe a unique concept based on yeast cell-surface display technology to selectively track eligible peptides with agonistic activity for human GPCRs (Cell Wall Trapping of Autocrine Peptides (CWTrAP strategy. In our strategy, individual recombinant yeast cells are able to report autocrine-positive activity for human GPCRs by expressing a candidate peptide fused to an anchoring motif. Following expression and activation, yeast cells trap autocrine peptides onto their cell walls. Because captured peptides are incapable of diffusion, they have no impact on surrounding yeast cells that express the target human GPCR and non-signaling peptides. Therefore, individual yeast cells can assemble the autonomous signaling complex and allow single-cell screening of a yeast population. Our strategy may be applied to identify eligible peptides with agonistic activity for target human GPCRs.

Sharing the cell's bounty - organelle inheritance in yeast.

Science.gov (United States)

Knoblach, Barbara; Rachubinski, Richard A

2015-02-15

Eukaryotic cells replicate and partition their organelles between the mother cell and the daughter cell at cytokinesis. Polarized cells, notably the budding yeast Saccharomyces cerevisiae, are well suited for the study of organelle inheritance, as they facilitate an experimental dissection of organelle transport and retention processes. Much progress has been made in defining the molecular players involved in organelle partitioning in yeast. Each organelle uses a distinct set of factors - motor, anchor and adaptor proteins - that ensures its inheritance by future generations of cells. We propose that all organelles, regardless of origin or copy number, are partitioned by the same fundamental mechanism involving division and segregation. Thus, the mother cell keeps, and the daughter cell receives, their fair and equitable share of organelles. This mechanism of partitioning moreover facilitates the segregation of organelle fragments that are not functionally equivalent. In this Commentary, we describe how this principle of organelle population control affects peroxisomes and other organelles, and outline its implications for yeast life span and rejuvenation. © 2015. Published by The Company of Biologists Ltd.

Sorption of strontium by magnetically modified yeast cells

International Nuclear Information System (INIS)

Hu Yantao; Ji Yanqin; Tian Qing; Shao Xianzhang; Shi Jianhe; Ivo Safarik; Zhang Shengdong; Li Jinying

2008-01-01

Magnetically modified fodder's yeast (Kluyveromyces fragilis) cells using water based magnetic fluid, were characterized by scanning electron microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The sorption-desorption properties of Sr 2+ by these yeast cells from nitrate salt of Sr 2+ were studied. The results demonstrated that the Sr 2+ sorption volume by these cells enhanced with increasing pH and reached a plateau between pH 4.0 and 7.0. A minor effect by temperature was observed. The sorption volumes are 19.5 mg/g and 53.5 mg/g from 10 ppm and 40 ppm Sr 2+ solution respectively within 20 min. The sorption of Sr 2+ in these cells can be desorbed under 0.1 mol/L HNO 3 solution. The maximum Sr 2+ sorption volume is 96.7 mg/g at 20℃. The sorption characteristic fits Langmuir model well with 140.8 mg/g calculated maximum sorption volume by these yeast cells. (authors)

A study on immobilized ethanol yeast cells by radiation technique

International Nuclear Information System (INIS)

Li Zhengkui; Zhang Bosen

1994-01-01

Hydrophilic monomer 2-hydroxyethyl acrylate (HEA) and a series of polyethylene glycol dimethacrylate monomers were copolymerized by radiation technique at low temperature (-78 degree C) and hydrophilic hydrogels were obtained. The immobilization of yeast cells with these copolymer carriers led to a higher ethanol productivity than free cells. Of all copolymer carriers, the ethanol yield with poly (HEA-14 G) was the highest, about 2.45 times as high as that of free yeast cells. In addition, the ethanol productivity of 12 batch repeated reactions with poly (HEA-14G) carrier was all higher than that of free yeast cells. The ethanol productivity of immobilized yeast cells was dependent on the proportion of hydrophilic monomer to other monomers in copolymer systems, the chain length of the bifunctional monomer, the degree of hydration of copolymer carriers, the structure of copolymer carriers and porosity in the internal structure of carriers. The ethanol yield of immobilized cells depended on swelling ability and porosity of copolymer carriers

High power density yeast catalyzed microbial fuel cells

Science.gov (United States)

Ganguli, Rahul

Microbial fuel cells leverage whole cell biocatalysis to convert the energy stored in energy-rich renewable biomolecules such as sugar, directly to electrical energy at high efficiencies. Advantages of the process include ambient temperature operation, operation in natural streams such as wastewater without the need to clean electrodes, minimal balance-of-plant requirements compared to conventional fuel cells, and environmentally friendly operation. These make the technology very attractive as portable power sources and waste-to-energy converters. The principal problem facing the technology is the low power densities compared to other conventional portable power sources such as batteries and traditional fuel cells. In this work we examined the yeast catalyzed microbial fuel cell and developed methods to increase the power density from such fuel cells. A combination of cyclic voltammetry and optical absorption measurements were used to establish significant adsorption of electron mediators by the microbes. Mediator adsorption was demonstrated to be an important limitation in achieving high power densities in yeast-catalyzed microbial fuel cells. Specifically, the power densities are low for the length of time mediator adsorption continues to occur. Once the mediator adsorption stops, the power densities increase. Rotating disk chronoamperometry was used to extract reaction rate information, and a simple kinetic expression was developed for the current observed in the anodic half-cell. Since the rate expression showed that the current was directly related to microbe concentration close to the electrode, methods to increase cell mass attached to the anode was investigated. Electrically biased electrodes were demonstrated to develop biofilm-like layers of the Baker's yeast with a high concentration of cells directly connected to the electrode. The increased cell mass did increase the power density 2 times compared to a non biofilm fuel cell, but the power density

Anhydrobiosis in yeast: cell wall mannoproteins are important for yeast Saccharomyces cerevisiae resistance to dehydration.

Science.gov (United States)

Borovikova, Diana; Teparić, Renata; Mrša, Vladimir; Rapoport, Alexander

2016-08-01

The state of anhydrobiosis is linked with the reversible delay of metabolism as a result of strong dehydration of cells, and is widely distributed in nature. A number of factors responsible for the maintenance of organisms' viability in these conditions have been revealed. This study was directed to understanding how changes in cell wall structure may influence the resistance of yeasts to dehydration-rehydration. Mutants lacking various cell wall mannoproteins were tested to address this issue. It was revealed that mutants lacking proteins belonging to two structurally and functionally unrelated groups (proteins non-covalently attached to the cell wall, and Pir proteins) possessed significantly lower cell resistance to dehydration-rehydration than the mother wild-type strain. At the same time, the absence of the GPI-anchored cell wall protein Ccw12 unexpectedly resulted in an increase of cell resistance to this treatment; this phenomenon is explained by the compensatory synthesis of chitin. The results clearly indicate that the cell wall structure/composition relates to parameters strongly influencing yeast viability during the processes of dehydration-rehydration, and that damage to cell wall proteins during yeast desiccation can be an important factor leading to cell death. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

The impact of metabolism on aging and cell size in single yeast cells

NARCIS (Netherlands)

Huberts, Daphne

2015-01-01

The aim of this thesis was to determine how metabolism affects yeast aging in single yeast cells using a novel microfluidic device. We first review how cells are able to sense nutrients in their environment and then describe the use of the microfluidic dissection platform that greatly improves our

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

Science.gov (United States)

Sakai, A; Kobayashi, S; Oiyama, I

1990-06-01

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 25°C for 5 min and then chilled PVS2 at 0°C for 3 min. The cell suspension of about 0.1 ml was loaded in a 0.5 ml transparent plastic straw and directly plunged in liquid nitrogen for 30 min. After rapid warming, the cell suspension was expelled in 2 ml of MT medium containing 1.2 M sucrose. The average rate of survival was about 80%. The vitrified cells regenerated plantlets. This method is very simple and the time required for cryopreservation is only about 10 min.

Yeast cell surface display for lipase whole cell catalyst and its applications

Energy Technology Data Exchange (ETDEWEB)

Liu, Yun; Zhang, Rui; Lian, Zhongshuai; Wang, Shihui; Wright, Aaron T.

2014-08-01

The cell surface display technique allows for the expression of target proteins or peptides on the microbial cell surface by fusing an appropriate protein as an anchoring motif. Yeast display systems, such as Pichia pastoris, Yarowia lipolytica and Saccharomyces cerevisiae, are ideal, alternative and extensive display systems with the advantage of simple genetic manipulation and post-translational modification of expressed heterologous proteins. Engineered yeasts show high performance characteristics and variant utilizations. Herein, we comprehensively summarize the variant factors affecting lipase whole cell catalyst activity and display efficiency, including the structure and size of target proteins, screening anchor proteins, type and chain length of linkers, and the appropriate matching rules among the above-mentioned display units. Furthermore, we also address novel approaches to enhance stability and activity of recombinant lipases, such as VHb gene co-expression, multi-enzyme co-display technique, and the micro-environmental interference and self-assembly techniques. Finally, we represent the variety of applications of whole cell surface displayed lipases on yeast cells in non-aqueous phases, including synthesis of esters, PUFA enrichment, resolution of chiral drugs, organic synthesis and biofuels. We demonstrate that the lipase surface display technique is a powerful tool for functionalizing yeasts to serve as whole cell catalysts, and increasing interest is providing an impetus for broad application of this technique.

Fungal dimorphism: the switch from hyphae to yeast is a specialized morphogenetic adaptation allowing colonization of a host.

Science.gov (United States)

Boyce, Kylie J; Andrianopoulos, Alex

2015-11-01

The ability of pathogenic fungi to switch between a multicellular hyphal and unicellular yeast growth form is a tightly regulated process known as dimorphic switching. Dimorphic switching requires the fungus to sense and respond to the host environment and is essential for pathogenicity. This review will focus on the role of dimorphism in fungi commonly called thermally dimorphic fungi, which switch to a yeast growth form during infection. This group of phylogenetically diverse ascomycetes includes Talaromyces marneffei (recently renamed from Penicillium marneffei), Blastomyces dermatitidis (teleomorph Ajellomyces dermatitidis), Coccidioides species (C. immitis and C. posadasii), Histoplasma capsulatum (teleomorph Ajellomyces capsulatum), Paracoccidioides species (P. brasiliensis and P. lutzii) and Sporothrix schenckii (teleomorph Ophiostoma schenckii). This review will explore both the signalling pathways regulating the morphological transition and the transcriptional responses necessary for intracellular growth. The physiological requirements of yeast cells during infection will also be discussed, highlighting recent advances in the understanding of the role of iron and calcium acquisition during infection. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA.

Science.gov (United States)

Gao, Qiuqiang; Liou, Liang-Chun; Ren, Qun; Bao, Xiaoming; Zhang, Zhaojie

2014-03-03

The yeast cell wall plays an important role in maintaining cell morphology, cell integrity and response to environmental stresses. Here, we report that salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA (ρ 0 ). Upon salt treatment, the cell wall is thickened, broken and becomes more sensitive to the cell wall-perturbing agent sodium dodecyl sulfate (SDS). Also, SCW11 mRNA levels are elevated in ρ 0 cells. Deletion of SCW11 significantly decreases the sensitivity of ρ 0 cells to SDS after salt treatment, while overexpression of SCW11 results in higher sensitivity. In addition, salt stress in ρ 0 cells induces high levels of reactive oxygen species (ROS), which further damages the cell wall, causing cells to become more sensitive towards the cell wall-perturbing agent.

Radiosensitivity of yeast cells as a function of radiation LET

International Nuclear Information System (INIS)

Lobachevskij, P.N.; Krasavin, E.A.

1988-01-01

A model is proposed for interpreting the radiosensitivity of yeast cells as a function of linear energy transfer (LET) of ionizing radiation. The model takes into account the role of repair processes in sensitivity of yeast cells to ionizing radiation of different LET. Two types of repair are discussed: (1) a nonspecific repair (characteristic of both haploid and diploid cells), and (2) a diploid - soecific repair (characteristic of diploid cells only)

Toxicity of Aromatic Ketone to Yeast Cell and Improvement of the Asymmetric Reduction of Aromatic Ketone Catalyzed by Yeast Cell with the Introduction of Resin Adsorption

Directory of Open Access Journals (Sweden)

Zhong-Hua Yang

2008-01-01

Full Text Available Asymmetric reduction of the prochiral aromatic ketone catalyzed by yeast cells is one of the most promising routes to produce its corresponding enantiopure aromatic alcohol, but the space-time yield does not meet people’s expectations. Therefore, the toxicity of aromatic ketone and aromatic alcohol to the yeast cell is investigated in this work. It has been found that the aromatic compounds are poisonous to the yeast cell. The activity of yeast cell decreases steeply when the concentration of acetophenone (ACP is higher than 30.0 mmol/L. Asymmetric reduction of acetophenone to chiral S-α-phenylethyl alcohol (PEA catalyzed by the yeast cell was chosen as the model reaction to study in detail the promotion effect of the introduction of the resin adsorption on the asymmetric reduction reaction. The resin acts as the substrate reservoir and product extraction agent in situ. It has been shown that this reaction could be remarkably improved with this technique when the appropriate kind of resin is applied. The enantioselectivity and yield are acceptable even though the initial ACP concentration reaches 72.2 mmol/L.

Single-particle tracking of quantum dot-conjugated prion proteins inside yeast cells

Energy Technology Data Exchange (ETDEWEB)

Tsuji, Toshikazu; Kawai-Noma, Shigeko [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Pack, Chan-Gi [Cellular Informatics Laboratory, RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198 (Japan); Terajima, Hideki [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Yajima, Junichiro; Nishizaka, Takayuki [Department of Physics, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588 (Japan); Kinjo, Masataka [Laboratory of Molecular Cell Dynamics, Graduate School of Life Sciences, Hokkaido University, Sapporo 001-0021 (Japan); Taguchi, Hideki, E-mail: taguchi@bio.titech.ac.jp [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan)

2011-02-25

Research highlights: {yields} We develop a method to track a quantum dot-conjugated protein in yeast cells. {yields} We incorporate the conjugated quantum dot proteins into yeast spheroplasts. {yields} We track the motions by conventional or 3D tracking microscopy. -- Abstract: Yeast is a model eukaryote with a variety of biological resources. Here we developed a method to track a quantum dot (QD)-conjugated protein in the budding yeast Saccharomyces cerevisiae. We chemically conjugated QDs with the yeast prion Sup35, incorporated them into yeast spheroplasts, and tracked the motions by conventional two-dimensional or three-dimensional tracking microscopy. The method paves the way toward the individual tracking of proteins of interest inside living yeast cells.

Single-particle tracking of quantum dot-conjugated prion proteins inside yeast cells

International Nuclear Information System (INIS)

Tsuji, Toshikazu; Kawai-Noma, Shigeko; Pack, Chan-Gi; Terajima, Hideki; Yajima, Junichiro; Nishizaka, Takayuki; Kinjo, Masataka; Taguchi, Hideki

2011-01-01

Research highlights: → We develop a method to track a quantum dot-conjugated protein in yeast cells. → We incorporate the conjugated quantum dot proteins into yeast spheroplasts. → We track the motions by conventional or 3D tracking microscopy. -- Abstract: Yeast is a model eukaryote with a variety of biological resources. Here we developed a method to track a quantum dot (QD)-conjugated protein in the budding yeast Saccharomyces cerevisiae. We chemically conjugated QDs with the yeast prion Sup35, incorporated them into yeast spheroplasts, and tracked the motions by conventional two-dimensional or three-dimensional tracking microscopy. The method paves the way toward the individual tracking of proteins of interest inside living yeast cells.

Apoptosis-like yeast cell death in response to DNA damage and replication defects

Energy Technology Data Exchange (ETDEWEB)

Burhans, William C.; Weinberger, Martin; Marchetti, Maria A.; Ramachandran, Lakshmi; D' Urso, Gennaro; Huberman, Joel A

2003-11-27

In budding (Saccharomyces cerevisiae) and fission (Schizosaccharomyces pombe) yeast and other unicellular organisms, DNA damage and other stimuli can induce cell death resembling apoptosis in metazoans, including the activation of a recently discovered caspase-like molecule in budding yeast. Induction of apoptotic-like cell death in yeasts requires homologues of cell cycle checkpoint proteins that are often required for apoptosis in metazoan cells. Here, we summarize these findings and our unpublished results which show that an important component of metazoan apoptosis recently detected in budding yeast - reactive oxygen species (ROS) - can also be detected in fission yeast undergoing an apoptotic-like cell death. ROS were detected in fission and budding yeast cells bearing conditional mutations in genes encoding DNA replication initiation proteins and in fission yeast cells with mutations that deregulate cyclin-dependent kinases (CDKs). These mutations may cause DNA damage by permitting entry of cells into S phase with a reduced number of replication forks and/or passage through mitosis with incompletely replicated chromosomes. This may be relevant to the frequent requirement for elevated CDK activity in mammalian apoptosis, and to the recent discovery that the initiation protein Cdc6 is destroyed during apoptosis in mammals and in budding yeast cells exposed to lethal levels of DNA damage. Our data indicate that connections between apoptosis-like cell death and DNA replication or CDK activity are complex. Some apoptosis-like pathways require checkpoint proteins, others are inhibited by them, and others are independent of them. This complexity resembles that of apoptotic pathways in mammalian cells, which are frequently deregulated in cancer. The greater genetic tractability of yeasts should help to delineate these complex pathways and their relationships to cancer and to the effects of apoptosis-inducing drugs that inhibit DNA replication.

Apoptosis-like yeast cell death in response to DNA damage and replication defects

International Nuclear Information System (INIS)

Burhans, William C.; Weinberger, Martin; Marchetti, Maria A.; Ramachandran, Lakshmi; D'Urso, Gennaro; Huberman, Joel A.

2003-01-01

In budding (Saccharomyces cerevisiae) and fission (Schizosaccharomyces pombe) yeast and other unicellular organisms, DNA damage and other stimuli can induce cell death resembling apoptosis in metazoans, including the activation of a recently discovered caspase-like molecule in budding yeast. Induction of apoptotic-like cell death in yeasts requires homologues of cell cycle checkpoint proteins that are often required for apoptosis in metazoan cells. Here, we summarize these findings and our unpublished results which show that an important component of metazoan apoptosis recently detected in budding yeast - reactive oxygen species (ROS) - can also be detected in fission yeast undergoing an apoptotic-like cell death. ROS were detected in fission and budding yeast cells bearing conditional mutations in genes encoding DNA replication initiation proteins and in fission yeast cells with mutations that deregulate cyclin-dependent kinases (CDKs). These mutations may cause DNA damage by permitting entry of cells into S phase with a reduced number of replication forks and/or passage through mitosis with incompletely replicated chromosomes. This may be relevant to the frequent requirement for elevated CDK activity in mammalian apoptosis, and to the recent discovery that the initiation protein Cdc6 is destroyed during apoptosis in mammals and in budding yeast cells exposed to lethal levels of DNA damage. Our data indicate that connections between apoptosis-like cell death and DNA replication or CDK activity are complex. Some apoptosis-like pathways require checkpoint proteins, others are inhibited by them, and others are independent of them. This complexity resembles that of apoptotic pathways in mammalian cells, which are frequently deregulated in cancer. The greater genetic tractability of yeasts should help to delineate these complex pathways and their relationships to cancer and to the effects of apoptosis-inducing drugs that inhibit DNA replication

Construction of the yeast whole-cell Rhizopus oryzae lipase biocatalyst with high activity.

Science.gov (United States)

Chen, Mei-ling; Guo, Qin; Wang, Rui-zhi; Xu, Juan; Zhou, Chen-wei; Ruan, Hui; He, Guo-qing

2011-07-01

Surface display is effectively utilized to construct a whole-cell biocatalyst. Codon optimization has been proven to be effective in maximizing production of heterologous proteins in yeast. Here, the cDNA sequence of Rhizopus oryzae lipase (ROL) was optimized and synthesized according to the codon bias of Saccharomyces cerevisiae, and based on the Saccharomyces cerevisiae cell surface display system with α-agglutinin as an anchor, recombinant yeast displaying fully codon-optimized ROL with high activity was successfully constructed. Compared with the wild-type ROL-displaying yeast, the activity of the codon-optimized ROL yeast whole-cell biocatalyst (25 U/g dried cells) was 12.8-fold higher in a hydrolysis reaction using p-nitrophenyl palmitate (pNPP) as the substrate. To our knowledge, this was the first attempt to combine the techniques of yeast surface display and codon optimization for whole-cell biocatalyst construction. Consequently, the yeast whole-cell ROL biocatalyst was constructed with high activity. The optimum pH and temperature for the yeast whole-cell ROL biocatalyst were pH 7.0 and 40 °C. Furthermore, this whole-cell biocatalyst was applied to the hydrolysis of tributyrin and the resulted conversion of butyric acid reached 96.91% after 144 h.

Lymphocutaneous nocardiosis due to Nocardia brasiliensis.

Science.gov (United States)

Maraki, Sofia; Scoulica, Efstathia; Alpantaki, Kalliopi; Dialynas, Michael; Tselentis, Yannis

2003-09-01

Nocardia species are Gram-positive bacteria responsible for systemic or cutaneous infections in humans. Nocardia brasiliensis is the most common infective agent in the cutaneous form of nocardiosis. We describe a case of a previously healthy man, who presented with lymphocutaneous Nocardia brasiliensis infection, and was successfully treated with trimethoprim-sulfamethoxazole. The identification of the isolate was confirmed by nucleotide sequence analysis of the 16S rRNA gene.

Hydrothermal decomposition of yeast cells for production of proteins and amino acids

Energy Technology Data Exchange (ETDEWEB)

Lamoolphak, Wiwat [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand); Goto, Motonobu [Department of Applied Chemistry and Biochemistry, Kumamoto University, Kumamoto 850-8555 (Japan); Sasaki, Mitsuru [Department of Applied Chemistry and Biochemistry, Kumamoto University, Kumamoto 850-8555 (Japan); Suphantharika, Manop [Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400 (Thailand); Muangnapoh, Chirakarn [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand); Prommuag, Chattip [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand); Shotipruk, Artiwan [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand)]. E-mail: artiwan.s@chula.ac.th

2006-10-11

This study examines hydrothermal decomposition of Baker's yeast cells, used as a model for spent Brewer's yeast waste, into protein and amino acids. The reaction was carried out in a closed batch reactor at various temperatures between 100 and 250 deg. C. The reaction products were separated into water-soluble and solid residue. The results demonstrated that the amount of yeast residue decreased with increasing hydrolysis temperature. After 20 min reaction in water at 250 deg. C, 78% of yeast was decomposed. The highest amount of protein produced was also obtained at this condition and was found to be 0.16 mg/mg dry yeast. The highest amount of amino acids (0.063 mg/mg dry yeast) was found at the lowest temperature tested after 15 min. The hydrolysis product obtained at 200 deg. C was tested as a nutrient source for yeast growth. The growth of yeast cells in the culture medium containing 2 w/v% of this product was comparable to that of the cells grown in the medium containing commercial yeast extract at the same concentration. These results demonstrated the feasibility of using subcritical water to potentially decompose proteinaceous waste such as spent Brewer's yeast while recovering more useful products.

Hydrothermal decomposition of yeast cells for production of proteins and amino acids

International Nuclear Information System (INIS)

Lamoolphak, Wiwat; Goto, Motonobu; Sasaki, Mitsuru; Suphantharika, Manop; Muangnapoh, Chirakarn; Prommuag, Chattip; Shotipruk, Artiwan

2006-01-01

This study examines hydrothermal decomposition of Baker's yeast cells, used as a model for spent Brewer's yeast waste, into protein and amino acids. The reaction was carried out in a closed batch reactor at various temperatures between 100 and 250 deg. C. The reaction products were separated into water-soluble and solid residue. The results demonstrated that the amount of yeast residue decreased with increasing hydrolysis temperature. After 20 min reaction in water at 250 deg. C, 78% of yeast was decomposed. The highest amount of protein produced was also obtained at this condition and was found to be 0.16 mg/mg dry yeast. The highest amount of amino acids (0.063 mg/mg dry yeast) was found at the lowest temperature tested after 15 min. The hydrolysis product obtained at 200 deg. C was tested as a nutrient source for yeast growth. The growth of yeast cells in the culture medium containing 2 w/v% of this product was comparable to that of the cells grown in the medium containing commercial yeast extract at the same concentration. These results demonstrated the feasibility of using subcritical water to potentially decompose proteinaceous waste such as spent Brewer's yeast while recovering more useful products

Yeast CUP1 protects HeLa cells against copper-induced stress

Energy Technology Data Exchange (ETDEWEB)

Xie, X.X. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China); College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou (China); Ma, Y.F.; Wang, Q.S.; Chen, Z.L.; Liao, R.R.; Pan, Y.C. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China)

2015-06-12

As an essential trace element, copper can be toxic in mammalian cells when present in excess. Metallothioneins (MTs) are small, cysteine-rich proteins that avidly bind copper and thus play an important role in detoxification. YeastCUP1 is a member of the MT gene family. The aim of this study was to determine whether yeast CUP1 could bind copper effectively and protect cells against copper stress. In this study,CUP1 expression was determined by quantitative real-time PCR, and copper content was detected by inductively coupled plasma mass spectrometry. Production of intracellular reactive oxygen species (ROS) was evaluated using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay. Cellular viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell cycle distribution of CUP1 was analyzed by fluorescence-activated cell sorting. The data indicated that overexpression of yeast CUP1 in HeLa cells played a protective role against copper-induced stress, leading to increased cellular viability (P<0.05) and decreased ROS production (P<0.05). It was also observed that overexpression of yeast CUP1 reduced the percentage of G1 cells and increased the percentage of S cells, which suggested that it contributed to cell viability. We found that overexpression of yeast CUP1 protected HeLa cells against copper stress. These results offer useful data to elucidate the mechanism of the MT gene on copper metabolism in mammalian cells.

Cell wall staining with Trypan blue enables quantitative analysis of morphological changes in yeast cells

DEFF Research Database (Denmark)

Liesche, Johannes; Marek, Magdalena; Günther-Pomorski, Thomas

2015-01-01

staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall......Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective...... with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain...

Immobilization of yeast cells with ionic hydrogel produced by radiation polymerization

International Nuclear Information System (INIS)

Lu Zhaoxin; Fujimura, T.

1990-01-01

The mixture of an ionic monomer of 2-acrylamido 2-methylpropane-sulfonic acid and a series of polyethylene glycol dimethacrylate monomer were polymerized at-78 deg C with 60 Co γ-rays and were used for immobilization of yeast cells. The immobilized yeast cells with these carriers had higher ethanol productivity than that without any carriers. The yield of ethanol with poly TBAS-14G carrier was the highest, and increased by 3.5 times compared with the free yeast cells. It was found that the ethanol yield increased with the increase of the glycol number in polyethylene glycol dimethacrylate. The state of the immobilized cells was observed with microscope and it was found that the difference in the ethanol productivity was mainly due to the difference in the internal structure and the properties of polymer carrier. It was considered that the polymer carrier had a proper hydrophilicity, swelling ability, cation in the surface and porousity in the internal structure for immobilizing yeast cells

A Predictive Model for Yeast Cell Polarization in Pheromone Gradients.

Science.gov (United States)

Muller, Nicolas; Piel, Matthieu; Calvez, Vincent; Voituriez, Raphaël; Gonçalves-Sá, Joana; Guo, Chin-Lin; Jiang, Xingyu; Murray, Andrew; Meunier, Nicolas

2016-04-01

Budding yeast cells exist in two mating types, a and α, which use peptide pheromones to communicate with each other during mating. Mating depends on the ability of cells to polarize up pheromone gradients, but cells also respond to spatially uniform fields of pheromone by polarizing along a single axis. We used quantitative measurements of the response of a cells to α-factor to produce a predictive model of yeast polarization towards a pheromone gradient. We found that cells make a sharp transition between budding cycles and mating induced polarization and that they detect pheromone gradients accurately only over a narrow range of pheromone concentrations corresponding to this transition. We fit all the parameters of the mathematical model by using quantitative data on spontaneous polarization in uniform pheromone concentration. Once these parameters have been computed, and without any further fit, our model quantitatively predicts the yeast cell response to pheromone gradient providing an important step toward understanding how cells communicate with each other.

Phytotoxic potential of Drimys brasiliensis Miers for use in weed control

Directory of Open Access Journals (Sweden)

Simoni Anese

2015-10-01

Full Text Available This study aims to evaluate the phytotoxicity potential of leaf and root extracts of Drimys brasiliensis on the germination and seedling growth of Panicum maximum and Euphorbia heterophylla and its influence on metaxylem cell size in the seedling roots of the latter specie. The leaf and root extracts were fractionated by partition chromatography, and the hexane and ethyl acetate fractions obtained from each organ were evaluated at different concentrations for phytotoxic activity in several bioassays. In seedling growth tests, we compared the effects of these fractions with the herbicide oxyfluorfen. The hexane fraction of the root extracts showed a higher inhibitory potential on the germination and growth of weeds and reduced the average size of the metaxylem cells of E. heterophylla roots by more than 50%.The inhibitory effects of the root hexane fraction on seedling growth was similar to the herbicide, indicating that D. brasiliensis is a possible alternative form of control for the weed species examined.

Inducible deletion of CD28 prior to secondary nippostrongylus brasiliensis infection impairs worm expulsion and recall of protective memory CD4⁺ T cell responses.

Directory of Open Access Journals (Sweden)

Hlumani Ndlovu

2014-02-01

Full Text Available IL-13 driven Th2 immunity is indispensable for host protection against infection with the gastrointestinal nematode Nippostronglus brasiliensis. Disruption of CD28 mediated costimulation impairs development of adequate Th2 immunity, showing an importance for CD28 during the initiation of an immune response against this pathogen. In this study, we used global CD28⁻/⁻ mice and a recently established mouse model that allows for inducible deletion of the cd28 gene by oral administration of tamoxifen (CD28(-/loxCre⁺/⁻+TM to resolve the controversy surrounding the requirement of CD28 costimulation for recall of protective memory responses against pathogenic infections. Following primary infection with N. brasiliensis, CD28⁻/⁻ mice had delayed expulsion of adult worms in the small intestine compared to wild-type C57BL/6 mice that cleared the infection by day 9 post-infection. Delayed expulsion was associated with reduced production of IL-13 and reduced serum levels of antigen specific IgG1 and total IgE. Interestingly, abrogation of CD28 costimulation in CD28(-/loxCre⁺/⁻ mice by oral administration of tamoxifen prior to secondary infection with N. brasiliensis resulted in impaired worm expulsion, similarly to infected CD28⁻/⁻ mice. This was associated with reduced production of the Th2 cytokines IL-13 and IL-4, diminished serum titres of antigen specific IgG1 and total IgE and a reduced CXCR5⁺ T(FH cell population. Furthermore, total number of CD4⁺ T cells and B220⁺ B cells secreting Th1 and Th2 cytokines were significantly reduced in CD28⁻/⁻ mice and tamoxifen treated CD28(-/loxCre⁺/⁻ mice compared to C57BL/6 mice. Importantly, interfering with CD28 costimulatory signalling before re-infection impaired the recruitment and/or expansion of central and effector memory CD4⁺ T cells and follicular B cells to the draining lymph node of tamoxifen treated CD28(-/loxCre⁺/⁻ mice. Therefore, it can be concluded that CD28

Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts

Czech Academy of Sciences Publication Activity Database

Pálková, Z.; Váchová, Libuše

2016-01-01

Roč. 57, SEP (2016), s. 110-119 ISSN 1084-9521 R&D Projects: GA ČR GA13-08605S; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Pathogenic yeasts * Biofilms and colonies * Cell differentiation Subject RIV: EE - Microbiology, Virology Impact factor: 6.614, year: 2016

Effects of gamma radiation on Sporothrix schenckii yeast cells

Energy Technology Data Exchange (ETDEWEB)

Lacerda, Camila M. de Sousa; Martins, Estefania Mara Nascimento; Andrade, Antero S.R. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)], e-mail: cmsl@cdtn.br, e-mail: estefaniabio@yahoo.com.br, e-mail: antero@cdtn.br; Resende, Maria Aparecida de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Microbiologia], e-mail: maressend@mono.icb.ufmg.br

2009-07-01

Sporotrichosis is a subacute or chronic infection caused by the fungus Sporothrix schenckii. Zoonotic transmission can occur after scratches or bites of animals, mainly cats, rodents, and armadillos. Up to the moment, no approved vaccine was reported for S. schenckii or to any important pathogenic fungi infection in humans, indicating the need to expand the research in this field and to explore new alternatives. The aim of this study was to evaluate the effects of gamma radiation in the viability, metabolic activity and reproductive ability of S. schenckii yeast cells for further studies on the development of a vaccine for immunization of cats and dogs. The culture of S. schenckii, in solid medium, was irradiated at doses ranging from 1.0 to 9.0 kGy. After each dose the reproductive capacity, viability and protein synthesis were estimated. The results showed that a reduction of 6 log{sub 10} cycles in the number of colonies was achieved at 6.0 kGy and after 8.0 kGy no colonies could be recovered. The viability analysis indicated that yeast cells remained viable up to 9.0 kGy. The results of protein synthesis analysis showed that the yeast cells, irradiated up to 9.0 kGy, were able to synthesize proteins. Our preliminary results indicated that for the yeast cells of S. schenckii, it is possible to find an absorbed dose in which the pathogen loses its reproductive ability, while retaining its viability, a necessary condition for the development of a radioattenuated yeast vaccine. (author)

Effects of gamma radiation on Sporothrix schenckii yeast cells

International Nuclear Information System (INIS)

Lacerda, Camila M. de Sousa; Martins, Estefania Mara Nascimento; Andrade, Antero S.R.; Resende, Maria Aparecida de

2009-01-01

Sporotrichosis is a subacute or chronic infection caused by the fungus Sporothrix schenckii. Zoonotic transmission can occur after scratches or bites of animals, mainly cats, rodents, and armadillos. Up to the moment, no approved vaccine was reported for S. schenckii or to any important pathogenic fungi infection in humans, indicating the need to expand the research in this field and to explore new alternatives. The aim of this study was to evaluate the effects of gamma radiation in the viability, metabolic activity and reproductive ability of S. schenckii yeast cells for further studies on the development of a vaccine for immunization of cats and dogs. The culture of S. schenckii, in solid medium, was irradiated at doses ranging from 1.0 to 9.0 kGy. After each dose the reproductive capacity, viability and protein synthesis were estimated. The results showed that a reduction of 6 log 10 cycles in the number of colonies was achieved at 6.0 kGy and after 8.0 kGy no colonies could be recovered. The viability analysis indicated that yeast cells remained viable up to 9.0 kGy. The results of protein synthesis analysis showed that the yeast cells, irradiated up to 9.0 kGy, were able to synthesize proteins. Our preliminary results indicated that for the yeast cells of S. schenckii, it is possible to find an absorbed dose in which the pathogen loses its reproductive ability, while retaining its viability, a necessary condition for the development of a radioattenuated yeast vaccine. (author)

Cell-surface display of enzymes by the yeast Saccharomyces cerevisiae for synthetic biology.

Science.gov (United States)

Tanaka, Tsutomu; Kondo, Akihiko

2015-02-01

In yeast cell-surface displays, functional proteins, such as cellulases, are genetically fused to an anchor protein and expressed on the cell surface. Saccharomyces cerevisiae, which is often utilized as a cell factory for the production of fuels, chemicals, and proteins, is the most commonly used yeast for cell-surface display. To construct yeast cells with a desired function, such as the ability to utilize cellulose as a substrate for bioethanol production, cell-surface display techniques for the efficient expression of enzymes on the cell membrane need to be combined with metabolic engineering approaches for manipulating target pathways within cells. In this Minireview, we summarize the recent progress of biorefinery fields in the development and application of yeast cell-surface displays from a synthetic biology perspective and discuss approaches for further enhancing cell-surface display efficiency. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Yeast modulation of human dendritic cell cytokine secretion: an in vitro study.

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Ida M Smith

Full Text Available Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The concept of individual microorganisms influencing the makeup of T cell subsets via interactions with intestinal dendritic cells (DCs appears to constitute the foundation for immunoregulatory effects of probiotics, and several studies have reported probiotic strains resulting in reduction of intestinal inflammation through modulation of DC function. Consequent to a focus on Saccharomyces boulardii as the fundamental probiotic yeast, very little is known about hundreds of non-Saccharomyces yeasts in terms of their interaction with the human gastrointestinal immune system. The aim of the present study was to evaluate 170 yeast strains representing 75 diverse species for modulation of inflammatory cytokine secretion by human DCs in vitro, as compared to cytokine responses induced by a S. boulardii reference strain with probiotic properties documented in clinical trials. Furthermore, we investigated whether cytokine inducing interactions between yeasts and human DCs are dependent upon yeast viability or rather a product of membrane interactions regardless of yeast metabolic function. We demonstrate high diversity in yeast induced cytokine profiles and employ multivariate data analysis to reveal distinct clustering of yeasts inducing similar cytokine profiles in DCs, highlighting clear species distinction within specific yeast genera. The observed differences in induced DC cytokine profiles add to the currently very limited knowledge of the cross-talk between yeasts and human immune cells and provide a foundation for selecting yeast strains for further characterization and development toward potentially novel yeast probiotics. Additionally, we present data to support a hypothesis that the interaction between yeasts and human DCs does not solely depend on yeast viability, a concept which may suggest a need for further classifications

Yeast Modulation of Human Dendritic Cell Cytokine Secretion: An In Vitro Study

Science.gov (United States)

Smith, Ida M.; Christensen, Jeffrey E.; Arneborg, Nils; Jespersen, Lene

2014-01-01

Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The concept of individual microorganisms influencing the makeup of T cell subsets via interactions with intestinal dendritic cells (DCs) appears to constitute the foundation for immunoregulatory effects of probiotics, and several studies have reported probiotic strains resulting in reduction of intestinal inflammation through modulation of DC function. Consequent to a focus on Saccharomyces boulardii as the fundamental probiotic yeast, very little is known about hundreds of non-Saccharomyces yeasts in terms of their interaction with the human gastrointestinal immune system. The aim of the present study was to evaluate 170 yeast strains representing 75 diverse species for modulation of inflammatory cytokine secretion by human DCs in vitro, as compared to cytokine responses induced by a S. boulardii reference strain with probiotic properties documented in clinical trials. Furthermore, we investigated whether cytokine inducing interactions between yeasts and human DCs are dependent upon yeast viability or rather a product of membrane interactions regardless of yeast metabolic function. We demonstrate high diversity in yeast induced cytokine profiles and employ multivariate data analysis to reveal distinct clustering of yeasts inducing similar cytokine profiles in DCs, highlighting clear species distinction within specific yeast genera. The observed differences in induced DC cytokine profiles add to the currently very limited knowledge of the cross-talk between yeasts and human immune cells and provide a foundation for selecting yeast strains for further characterization and development toward potentially novel yeast probiotics. Additionally, we present data to support a hypothesis that the interaction between yeasts and human DCs does not solely depend on yeast viability, a concept which may suggest a need for further classifications beyond the current

The role of mitochondria in yeast programmed cell death

International Nuclear Information System (INIS)

Guaragnella, Nicoletta; Ždralević, Maša; Antonacci, Lucia; Passarella, Salvatore; Marra, Ersilia; Giannattasio, Sergio

2012-01-01

Mammalian apoptosis and yeast programmed cell death (PCD) share a variety of features including reactive oxygen species production, protease activity and a major role played by mitochondria. In view of this, and of the distinctive characteristics differentiating yeast and multicellular organism PCD, the mitochondrial contribution to cell death in the genetically tractable yeast Saccharomyces cerevisiae has been intensively investigated. In this mini-review we report whether and how yeast mitochondrial function and proteins belonging to oxidative phosphorylation, protein trafficking into and out of mitochondria, and mitochondrial dynamics, play a role in PCD. Since in PCD many processes take place over time, emphasis will be placed on an experimental model based on acetic acid-induced PCD (AA-PCD) which has the unique feature of having been investigated as a function of time. As will be described there are at least two AA-PCD pathways each with a multifaceted role played by mitochondrial components, in particular by cytochrome c.

Methods for Synchronization and Analysis of the Budding Yeast Cell Cycle.

Science.gov (United States)

Rosebrock, Adam P

2017-01-03

Like other eukaryotes, budding yeast temporally separate cell growth and division. DNA synthesis is distinct from chromosome segregation. Storage carbohydrates are accumulated slowly and then rapidly liquidated once per cycle. Cyclin-dependent kinase associates with multiple different transcriptionally and posttranslationally regulated cyclins to drive the cell cycle. These and other crucial events of cellular growth and division are limited to narrow windows of the cell cycle. Many experiments in the yeast laboratory treat a culture of cells as a homogeneous mixture. Measurements of asynchronous cultures are, however, confounded by the presence of cells in various cell cycle stages; measuring a population average in unsynchronized cells provides at best a decreased signal and at worst an artifactual result. A number of experimentally tractable methods have been developed to generate populations of yeast cells that are synchronized with respect to cell cycle phase. Robust methods for determining cell cycle position have also been developed. These methods are introduced here. © 2017 Cold Spring Harbor Laboratory Press.

Complete genome sequence of Nocardia brasiliensis HUJEG-1.

Science.gov (United States)

Vera-Cabrera, Lucio; Ortiz-Lopez, Rocio; Elizondo-Gonzalez, Ramiro; Perez-Maya, Antonio Ali; Ocampo-Candiani, Jorge

2012-05-01

In Mexico, actinomycetoma is mainly caused by Nocardia brasiliensis, which is a soil inhabitant actinobacterium. Here, we report for the first time the draft genome of a strain isolated from a human case that has largely been found in in vitro and experimental models of actinomycetoma, N. brasiliensis HUJEG-1.

Binding kinetics of magnetic nanoparticles on latex beads and yeast cells studied by magnetorelaxometry

International Nuclear Information System (INIS)

Eberbeck, Dietmar; Bergemann, Christian; Hartwig, Stefan; Steinhoff, Uwe; Trahms, Lutz

2005-01-01

The ion exchange mediated binding of magnetic nanoparticles (MNP) to modified latex spheres and yeast cells was quantified using magnetorelaxometry. By fitting subsequently recorded relaxation curves, the kinetics of the binding reactions was extracted. The signal of MNP with weak ion exchanger groups bound to latex and yeast cells scales linearly with the concentration of latex beads or yeast cells whereas that of MNP with strong ion exchanger groups is proportional to the square root of concentration. The binding of the latter leads to a much stronger aggregation of yeast cells than the former MNP

Bombus brasiliensis Lepeletier (Hymenoptera, Apidae infected with Nosema ceranae (Microsporidia

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Santiago Plischuk

Full Text Available ABSTRACT Heavy infections caused by a microsporidium were detected in midgut epithelium cells of two adult workers of the bumble bee Bombus brasiliensis Lepeletier collected near Puerto Iguazú, Misiones province, Argentina. Microsporidium rRNA (16S small subunit was amplified by 218MITOC primers and produced amplicons indicating presence of Nosema ceranae Fries et al., a virulent pathogen of more than 20 bee species, possibly involved in Apis mellifera L. Colony Collapse Disorder. Campaigns in search of B. brasiliensis between 2008 and 2015 have revealed a possible narrower range in the southeastern area of its known distribution. Effects of N. ceranae infections could be modulating their populations and should not be overlooked. In addition, the wide host range of this microsporidium makes it a potential threat to several endemic bees such as stingless (Meliponini and orchid bees (Euglossini.

A study of ethanol production of yeast cells immobilized with polymer carrier produced by radiation polymerization

International Nuclear Information System (INIS)

Lu Zhaoxin; Fujimura, Takashi

1993-01-01

Polymer carriers, poly(hydroxyethyl acrylate(HEA)-methoxy polyethylene glycol methylacrylate (M-23G)) and poly(hydroxyethyl acrylate(HEA)-glycidyl methylacrylate (GMA)) used for the immobilization of yeast cells were prepared by radiation polymerization at low temperature. Yeast cells were immobilized through adhesion and multiplication of yeast cells. The ethanol productivity of immobilized yeast cells with these carriers was related to the monomer composition of polymers and the optimum monomer composition was 20%:10% in poly(HEA-M-23G) and 17%:6% in poly(HEA-GMA). In this case, the ethanol productivity of immobilized yeast cells was about 4 times that of cells in free system. The relationship between the activity of immobilized yeast cells and the water content of the polymer carrier were also discussed. (author)

Possibility for simultaneous electricity generation and bioremediation by using Candida melibiosica yeast in biofuel cell

International Nuclear Information System (INIS)

Hubenova, Yolina; Georgiev, Danail; Mitov, Mario

2013-01-01

Recently, we have proved that Candida melibiosica 2491 yeast strain possesses electrogenic properties and could be used as a biocatalyst in yeast-based biofuel cells. In this paper we demonstrate that when the yeast is cultivated under polarization conditions in a biofuel cell its phytase activity exceeds that obtained during cultivation in a conventional bioreactor. Furthermore, there is a correlation between the yeast phytase activity and the electrical characteristic of the biofuel cell during the different yeast growth phases. The obtained results reveal a possibility for application of C.melibiosica for simultaneous electricity generation and bioremediation of hardly degradable polyphosphates, especially in the regions with intensive stock-farming. Keywords: Biofuel cells, yeast, Candida melibiosica, electricity generation, bioremediation

Expression of Nocardia brasiliensis superoxide dismutase during the early infection of murine peritoneal macrophages.

Science.gov (United States)

Revol, Agnès; Espinoza-Ruiz, Marisol; Medina-Villanueva, Igor; Salinas-Carmona, Mario Cesar

2006-12-01

Nocardia brasiliensis is the main agent of actinomycetoma in Mexico, but little is known about its virulence and molecular pathogenic pathways. These facultative intracellular bacteria are able to survive and divide within the host phagocytic cells, in part by neutralizing the reactive oxygen intermediates. Superoxide dismutase (SOD) participates in the intracellular survival of several bacterial species and, in particular, constitutes one of Nocardia asteroides virulence factors. To clarify SOD participation in the N. brasiliensis early infective process, we report its isolation and the consequent comparison of its transcript level. A 630 bp polymerase chain reaction fragment that included most of the coding sequence of N. brasiliensis sodA was cloned. A competitive assay was developed, allowing comparison of bacterial sod expression in exponential culture and 1 h after infecting peritoneal macrophages from BALB/c mice. At that time, there were viable bacteria in the macrophages. The intracellular bacteria presented a clear decrease in their sod transcript amount, although their 16S rRNA (used as an internal control) and hsp levels were maintained or slightly increased, respectively. These results indicate that sodA transcription is not maintained within the SOS bacterial response induced by phagosomal conditions. Further kinetics will be necessary to precisely define sod transcriptional regulation during N. brasiliensis intra-macrophage growth.

A high-throughput method for quantifying metabolically active yeast cells

DEFF Research Database (Denmark)

Nandy, Subir Kumar; Knudsen, Peter Boldsen; Rosenkjær, Alexander

2015-01-01

By redesigning the established methylene blue reduction test for bacteria and yeast, we present a cheap and efficient methodology for quantitative physiology of eukaryotic cells applicable for high-throughput systems. Validation of themethod in fermenters and highthroughput systems proved....... The drop in metabolic activity associated with the diauxic shift in yeast proved more pronounced for the MBRT-derived curve compared with OD curves, consistent with a dramatic shift in the ratio between live and dead cells at this metabolic event. This method provides a tool with numerous applications, e.......g. characterizing the death phase of stationary phase cultures, or in drug screens with pathogenic yeasts....

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

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Héctor Villalobos-Duno

Full Text Available α-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 α-1,3-glucan and allow remodeling of the cell wall, α-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 α-1,3-glucanase genes, was identified in the Paracoccidioides genome, and labeled AGN1. Transcriptional levels of AGN1 and AGS1 (α-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 α-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 α-1,3-glucan (SCMG, chemically modified from P. brasiliensis α-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 agn1Δ 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

Genomic Changes Associated with the Loss of Nocardia brasiliensis Virulence in Mice after 200 In Vitro Passages.

Science.gov (United States)

Gonzalez-Carrillo, Carolina; Millan-Sauceda, Cassandra; Lozano-Garza, Hector Gerardo; Ortiz-Lopez, Rocio; Elizondo-Gonzalez, Ramiro; Welsh, Oliverio; Ocampo-Candiani, Jorge; Vera-Cabrera, Lucio

2016-09-01

Nocardia species, particularly Nocardia brasiliensis, are etiologic agents of mycetoma, a chronic subcutaneous infection. Until now, little has been known about the pathogenic mechanisms involved in nocardial infection. Traditionally, subculture in rich media has been a simple way to induce attenuation. In this work, we report the changes in virulence toward mice and in genomic constitution of N. brasiliensis produced after 200 continuous subcultures in brain heart infusion (BHI) medium (P-200 strain). The ability of the N. brasiliensis P-200 strain to produce experimental infection was tested using BALB/c mice. P-200 was also used to immunize mice to determine whether it could induce resistance against a challenge with a nonsubcultured isolate (P-0). Comparative proteomic analysis between N. brasiliensis P-0 and P-200 was performed by two-dimensional (2-D) electrophoresis, and the genome sequence was obtained through Roche 454 sequence analysis. Virulence in BALB/c mice was completely lost, and BALB/c mice immunized with P-200 bacterial cells were resistant to mycetoma production by the nonsubcultured strain. Whole-genome sequence analysis revealed that P-200 lost a total of 262,913 bp distributed in 19 deleted regions, involving a total of 213 open reading frames (ORFs). The deleted genes included those encoding bacterial virulence factors, e.g., catalase, nitrate reductase enzymes, and a group of mammalian cell entry (MCE) family proteins, which may explain the loss of virulence of the isolate. Thus, completely attenuated N. brasiliensis was obtained after 200 passages in BHI medium, and putative Nocardia virulence genes were identified for the first time. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Adhesion of yeast cells on surface of polymers produced by radiation polymerization

International Nuclear Information System (INIS)

Lu, Zhaoxin; Takehisa, Masaaki; Xie Zongchuan.

1995-01-01

The adhesion of yeast (Saccharomyces formesences) cells on polymers was studied thermodynamically. The polymers were laminally prepared by means of radiation polymerization. By measuring contact angles, we calculated dispersion component and polar component of surface free energy of the polymers and the cells, and interfacial free energy between the polymer and the cells. Then interfacial free energy change of the cell adhesion to surface of the polymer was evaluated. The adhesion behavior of yeast cells on the polymers was observed by optical microscope. From above results, we conclude that the initial adhesion of the cells is related to the surface free energy of the polymer, but the irreversible adhesion may be close to the polar component in surface free energy. The high polar component is favourable the irreversible adhesion of yeast cells. (author)

Warburg effect and translocation-induced genomic instability: two yeast models for cancer cells

International Nuclear Information System (INIS)

Tosato, Valentina; Grüning, Nana-Maria; Breitenbach, Michael; Arnak, Remigiusz; Ralser, Markus; Bruschi, Carlo V.

2013-01-01

Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression (i) the activity of pyruvate kinase (PK), which recapitulates metabolic features of cancer cells, including the Warburg effect, and (ii) chromosome bridge-induced translocation (BIT) mimiking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect), and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, PK, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and post-translational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (“translocants”), between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the BIT system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

Warburg effect and translocation-induced genomic instability: two yeast models for cancer cells

Energy Technology Data Exchange (ETDEWEB)

Tosato, Valentina [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy); Grüning, Nana-Maria [Cambridge System Biology Center, Department of Biochemistry, University of Cambridge, Cambridge (United Kingdom); Breitenbach, Michael [Division of Genetics, Department of Cell Biology, University of Salzburg, Salzburg (Austria); Arnak, Remigiusz [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy); Ralser, Markus [Cambridge System Biology Center, Department of Biochemistry, University of Cambridge, Cambridge (United Kingdom); Bruschi, Carlo V., E-mail: bruschi@icgeb.org [International Centre for Genetic Engineering and Biotechnology, Trieste (Italy)

2013-01-18

Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression (i) the activity of pyruvate kinase (PK), which recapitulates metabolic features of cancer cells, including the Warburg effect, and (ii) chromosome bridge-induced translocation (BIT) mimiking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect), and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, PK, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and post-translational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (“translocants”), between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the BIT system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

WARBURG EFFECT AND TRANSLOCATION-INDUCED GENOMIC INSTABILITY: TWO YEAST MODELS FOR CANCER CELLS

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Valentina eTosato

2013-01-01

Full Text Available Yeast has been established as an efficient model system to study biological principles underpinning human health. In this review we focus on yeast models covering two aspects of cancer formation and progression i the activity of pyruvate kinase (PK, which recapitulates metabolic features of cancer cells, including the Warburg effect, and ii Bridge-Induced chromosome Translocation (BIT mimicking genome instability in cancer. Saccharomyces cerevisiae is an excellent model to study cancer cell metabolism, as exponentially growing yeast cells exhibit many metabolic similarities with rapidly proliferating cancer cells. The metabolic reconfiguration includes an increase in glucose uptake and fermentation, at the expense of respiration and oxidative phosphorylation (the Warburg effect, and involves a broad reconfiguration of nucleotide and amino acid metabolism. Both in yeast and humans, the regulation of this process seems to have a central player, pyruvate kinase, which is up-regulated in cancer, and to occur mostly on a post-transcriptional and posttranslational basis. Furthermore, BIT allows to generate selectable translocation-derived recombinants (translocants, between any two desired chromosomal locations, in wild-type yeast strains transformed with a linear DNA cassette carrying a selectable marker flanked by two DNA sequences homologous to different chromosomes. Using the Bridge-Induced Translocation system, targeted non-reciprocal translocations in mitosis are easily inducible. An extensive collection of different yeast translocants exhibiting genome instability and aberrant phenotypes similar to cancer cells has been produced and subjected to analysis. In this review, we hence provide an overview upon two yeast cancer models, and extrapolate general principles for mimicking human disease mechanisms in yeast.

Yeast cells contain a heterogeneous population of peroxisomes that segregate asymmetrically during cell division

NARCIS (Netherlands)

Kumar, Sanjeev; de Boer, Rinse; van der Klei, Ida J

2018-01-01

Here we used fluorescence microscopy and a peroxisome-targeted tandem fluorescent protein timer to determine the relative age of peroxisomes in yeast. Our data indicate that yeast cells contain a heterogeneous population of relatively old and younger peroxisomes. During budding the peroxisome

Production of mRNA cytokines in BALB/c mice infected with Paracoccidioides brasiliensis and analyses of the results by image processing; Producao de interleucinas RNAm em camundongos BALB/c infectados por Paracoccidioides brasiliensis, com analises dos resultados atraves de processamento de imagens

Energy Technology Data Exchange (ETDEWEB)

Januario, Adriana; Pietro, Rosemeire C.L. Rodrigues; Silva, Celio L. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Parasitologia, Microbiologia e Imunologia; Rodrigues, Evandro L.L.; Franca, Celso A. de [Sao Paulo Univ., Sao Carlos, SP (Brazil). Escola de Engenharia. Dept. de Engenharia Eletrica

1996-12-31

The production of mRNA cytokines in BALB/c mice infected with Paracoccidioides brasiliensis is studied. It is reported that in the beginning of the disease with P. brasiliensis stimulated mice showed an analogous production between IL-2 and IL-10 mRNA, however, there is a predominance of IL-2 mRNA in the lung and of IL-10 mRNA in the liver cells. In this model, there is a dynamic change in the levels of IL-2 and IL-10 mRNA, suggesting the presence of both CD4+ T helper cells 7 refs., 6 figs.

Ecotopes, Natural Infection and Trophic Resources of Triatoma brasiliensis (Hemiptera, Reduviidae, Triatominae

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Jane Costa

1998-01-01

Full Text Available Triatoma brasiliensis is considered as one of the most important Chagas disease vectors in the northeastern Brazil. This species presents chromatic variations which led to descriptions of subspecies, synonymized by Lent and Wygodzinsky (1979. In order to broaden bionomic knowledge of these distinct colour patterns of T. brasiliensis, captures were performed at different sites, where the chromatic patterns were described: Caicó, Rio Grande do Norte (T. brasiliensis brasiliensis Neiva, 1911, it will be called the "brasiliensis population"; Espinosa, Minas Gerais (T. brasiliensis melanica Neiva & Lent 1941, the "melanica population" and Petrolina, Pernambuco (T. brasiliensis macromelasoma, Galvão 1956, the "macromelasoma population". A fourth chromatic pattern was collected in Juazeiro, Bahia the darker one in overall cuticle coloration, the "Juazeiro population". At the sites of Caicó, Petrolina and Juazeiro, specimens were captured in peridomiciliar ecotopes and in wilderness. In Espinosa the specimens were collected only in wilderness, even though several exhaustive captures have been performed in peridomicile at different sites of this municipality. A total of 298 specimens were captured. The average registered infection rate was 15% for "brasiliensis population" and of 6.6% for "melanica population". Specimens of "macromelasoma" and of "Juazeiro populations" did not present natural infection. Concerning trophic resources, evaluated by the precipitin test, feeding eclecticism for the different colour patterns studied was observed, with dominance of goat blood in household surroundings as well as in wilderness

Assessing phagotrophy in the mixotrophic ciliate Paramecium bursaria using GFP-expressing yeast cells.

Science.gov (United States)

Miura, Takashi; Moriya, Hisao; Iwai, Sosuke

2017-07-03

We used cells of the yeast Saccharomyces cerevisiae expressing green fluorescent protein (GFP) as fluorescently labelled prey to assess the phagocytic activities of the mixotrophic ciliate Paramecium bursaria, which harbours symbiotic Chlorella-like algae. Because of different fluorescence spectra of GFP and algal chlorophyll, ingested GFP-expressing yeast cells can be distinguished from endosymbiotic algal cells and directly counted in individual P. bursaria cells using fluorescence microscopy. By using GFP-expressing yeast cells, we found that P. bursaria altered ingestion activities under different physiological conditions, such as different growth phases or the presence/absence of endosymbionts. Use of GFP-expressing yeast cells allowed us to estimate the digestion rates of live prey of the ciliate. In contrast to the ingestion activities, the digestion rate within food vacuoles was not affected by the presence of endosymbionts, consistent with previous findings that food and perialgal vacuoles are spatially and functionally separated in P. bursaria. Thus, GFP-expressing yeast may provide a valuable tool to assess both ingestion and digestion activities of ciliates that feed on eukaryotic organisms. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Yeast cell surface display: An efficient strategy for improvement of bioethanol fermentation performance.

Science.gov (United States)

Chen, Xianzhong

2017-03-04

The cell surface serves as a functional interface between the inside and the outside of the cell. Within the past 20 y the ability of yeast (Saccharomyces cerevisiae) to display heterologous proteins on the cell surface has been demonstrated. Furthermore, S. cerevisiae has been both developed and applied in expression of various proteins on the cell surface. Using this novel and useful strategy, proteins and peptides of various kinds can be displayed on the yeast cell surface by fusing the protein of interest with the glycosylphosphatidylinositol (GPI)-anchoring system. Consolidated bioprocessing (CBP) using S. cerevisiae represents a promising technology for bioethanol production. However, further work is needed to improve the fermentation performance. There is some excellent previous research regarding construction of yeast biocatalyst using the surface display system to decrease cost, increase efficiency of ethanol production and directly utilize starch or biomass for fuel production. In this commentary, we reviewed the yeast surface display system and highlighted recent work. Additionally, the strategy for decrease of phytate phosphate content in dried distillers grains with solubles (DDGS) by display of phytase on the yeast cell surface is discussed.

Use of non-conventional cell disruption method for extraction of proteins from black yeasts

Directory of Open Access Journals (Sweden)

Maja eLeitgeb

2016-04-01

Full Text Available The influence of pressure and treatment time on cells disruption of different black yeasts and on activities of extracted proteins using supercritical carbon dioxide process was studied. The cells of three different black yeasts Phaeotheca triangularis, Trimatostroma salinum and Wallemia ichthyophaga were exposed to supercritical carbon dioxide (SC CO2 by varying pressure at fixed temperature (35 °C. The black yeasts cell walls were disrupted and the content of the cells was spilled into the liquid medium. The impact of SC CO2 conditions on secretion of enzymes and proteins from black yeast cells suspension was studied. The residual activity of the enzymes cellulase, β-glucosidase, α-amylase and protease was studied by enzymatic assay. The viability of black yeast cells was determined by measuring the optical density of the cell suspension at 600 nm. The total protein concentration in the suspension was determined on UV-Vis spectrophotometer at 595 nm. The release of intracellular and extracellular products from black yeast cells was achieved. Also, the observation by an environmental scanning electron microscopy shows major morphological changes with SC CO2 treated cells. The advantages of the proposed method are in a simple use which is also possible for heat sensitive materials on one hand and on the other hand integration of the extraction of enzymes and their use in biocatalytical reactions.

Use of Non-Conventional Cell Disruption Method for Extraction of Proteins from Black Yeasts

Science.gov (United States)

Čolnik, Maja; Primožič, Mateja; Knez, Željko; Leitgeb, Maja

2016-01-01

The influence of pressure and treatment time on cells disruption of different black yeasts and on activities of extracted proteins using supercritical carbon dioxide process was studied. The cells of three different black yeasts Phaeotheca triangularis, Trimatostroma salinum, and Wallemia ichthyophaga were exposed to supercritical carbon dioxide (SC CO2) by varying pressure at fixed temperature (35°C). The black yeasts cell walls were disrupted, and the content of the cells was spilled into the liquid medium. The impact of SC CO2 conditions on secretion of enzymes and proteins from black yeast cells suspension was studied. The residual activity of the enzymes cellulase, β-glucosidase, α-amylase, and protease was studied by enzymatic assay. The viability of black yeast cells was determined by measuring the optical density of the cell suspension at 600 nm. The total protein concentration in the suspension was determined on UV–Vis spectrophotometer at 595 nm. The release of intracellular and extracellular products from black yeast cells was achieved. Also, the observation by an environmental scanning electron microscopy shows major morphological changes with SC CO2-treated cells. The advantages of the proposed method are in a simple use, which is also possible for heat-sensitive materials on one hand and on the other hand integration of the extraction of enzymes and their use in biocatalytical reactions. PMID:27148527

Cell wall staining with Trypan blue enables quantitative analysis of morphological changes in yeast cells.

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Liesche, Johannes; Marek, Magdalena; Günther-Pomorski, Thomas

2015-01-01

Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals, demonstrating the potential of this approach for morphological investigations or screening assays.

Cell wall staining with Trypan Blue enables quantitative analysis of morphological changes in yeast cells

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Johannes eLiesche

2015-02-01

Full Text Available Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals, demonstrating the potential of this approach for morphological investigations or screening assays.

Modifying infrared scattering effects of single yeast cells with plasmonic metal mesh

Science.gov (United States)

Malone, Marvin A.; Prakash, Suraj; Heer, Joseph M.; Corwin, Lloyd D.; Cilwa, Katherine E.; Coe, James V.

2010-11-01

The scattering effects in the infrared (IR) spectra of single, isolated bread yeast cells (Saccharomyces cerevisiae) on a ZnSe substrate and in metal microchannels have been probed by Fourier transform infrared imaging microspectroscopy. Absolute extinction [(3.4±0.6)×10-7 cm2 at 3178 cm-1], scattering, and absorption cross sections for a single yeast cell and a vibrational absorption spectrum have been determined by comparing it to the scattering properties of single, isolated, latex microspheres (polystyrene, 5.0 μm in diameter) on ZnSe, which are well modeled by the Mie scattering theory. Single yeast cells were then placed into the holes of the IR plasmonic mesh, i.e., metal films with arrays of subwavelength holes, yielding "scatter-free" IR absorption spectra, which have undistorted vibrational lineshapes and a rising generic IR absorption baseline. Absolute extinction, scattering, and absorption spectral profiles were determined for a single, ellipsoidal yeast cell to characterize the interplay of these effects.

Study on immobilized yeast cells with hydrophilic polymer carrier by radiation-induced copolymerization

International Nuclear Information System (INIS)

Li Zhengkui; Zhang Bosen

1993-01-01

Various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) are copolymerized by radiation technique at low temperature (-78 degree C) and several kinds of copolymer carriers were obtained. Yeast cells are immobilized through adhesion and multiplication of yeast cells themselves on these carriers. The ethanol productivity of immobilized yeast cells with these carriers was related to the monomer composition and water content of copolymer carriers and the optimum monomer composition was 20%:10% in poly (HEA-M23G). In this case, the ethanol productivity of immobilized yeast cells was 26 mg/(ml · h), which was 4 times as high as that of free cells. Effect of adding crosslinking reagent (4G) in lower monomer composition of poly(HEA-M23G) on the ethanol productivity of immobilized cells was better than that in higher one in this work

Bacterial toxin-antitoxin gene system as containment control in yeast cells

DEFF Research Database (Denmark)

Kristoffersen, P.; Jensen, G. B.; Gerdes, K.

2000-01-01

The potential of a bacterial toxin-antitoxin gene system for use in containment control in eukaryotes was explored. The Escherichia coli relE and relB genes were expressed in the yeast Saccharomyces cerevisiae, Expression of the relE gene was highly toxic to yeast cells. However, expression...... fermentation processes in which the escape of genetically modified cells would be considered highly risky....

Extraction of the number of peroxisomes in yeast cells by automated image analysis.

Science.gov (United States)

Niemistö, Antti; Selinummi, Jyrki; Saleem, Ramsey; Shmulevich, Ilya; Aitchison, John; Yli-Harja, Olli

2006-01-01

An automated image analysis method for extracting the number of peroxisomes in yeast cells is presented. Two images of the cell population are required for the method: a bright field microscope image from which the yeast cells are detected and the respective fluorescent image from which the number of peroxisomes in each cell is found. The segmentation of the cells is based on clustering the local mean-variance space. The watershed transformation is thereafter employed to separate cells that are clustered together. The peroxisomes are detected by thresholding the fluorescent image. The method is tested with several images of a budding yeast Saccharomyces cerevisiae population, and the results are compared with manually obtained results.

Bioadsorption of cadmium ion by cell surface-engineered yeasts displaying metallothionein and hexa-His

Energy Technology Data Exchange (ETDEWEB)

Kuroda, K.; Ueda, M. [Lab. of Applied Biological Chemistry, Kyoto Univ., Yoshida, Kyoto (Japan)

2004-07-01

The Cd{sup 2+}-chelating abilities of yeast metallothionein (YMT) and hexa-His displayed on the yeast-cell surface were compared. Display of YMT and hexa-His by {alpha}-agglutinin-based cell-surface engineering was confirmed by immunofluorescent labeling. Surface-engineered yeast cells with YMT and hexa-His fused in tandem showed superior cell-surface adsorption and recovery of Cd{sup 2+} under EDTA treatment on the cell surface than hexa-His-displaying cells. YMT was demonstrated to be more effective than hexa-His for the adsorption of Cd{sup 2+}. Yeast cells displaying YMT and/or hexa-His exhibited a higher potential for the adsorption of Cd{sup 2+} than Escherichia coli cells displaying these molecules. In order to investigate the effect of the displayed YMT and hexa-His on sensitivity to toxic Cd{sup 2+}, growth in Cd{sup 2+}-containing liquid medium was monitored. Unlike hexa-His-displaying cells, cells displaying YMT and hexa-His fused in tandem induced resistance to Cd{sup 2+} through active and enhanced adsorption of toxic Cd{sup 2+}. These results indicate that YMT-displaying yeast cells are a unique bioadsorbent with a functional chelating ability superior to that of E. coli. (orig.)

The Cell Wall-Associated Proteins in the Dimorphic Pathogenic Species of Paracoccidioides.

Science.gov (United States)

Puccia, Rosana; Vallejo, Milene C; Longo, Larissa V G

2017-01-01

Paracoccidioides brasiliensis and P. lutzii cause human paracoccidioidomycosis (PCM). They are dimorphic ascomycetes that grow as filaments at mild temperatures up to 28oC and as multibudding pathogenic yeast cells at 37oC. Components of the fungal cell wall have an important role in the interaction with the host because they compose the cell outermost layer. The Paracoccidioides cell wall is composed mainly of polysaccharides, but it also contains proportionally smaller rates of proteins, lipids, and melanin. The polysaccharide cell wall composition and structure of Paracoccidioides yeast cells, filamentous and transition phases were studied in detail in the past. Other cell wall components have been better analyzed in the last decades. The present work gives to the readers a detailed updated view of cell wall-associated proteins. Proteins that have been localized at the cell wall compartment using antibodies are individually addressed. We also make an overview about PCM, the Paracoccidioides cell wall structure, secretion mechanisms, and fungal extracellular vesicles. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

PCR with Paracoccidioides brasiliensis specific primers: potential use in ecological studies PCR com «primers» específicos de Paracoccidioides brasiliensis: uso potencial em estudos ecológicos

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S. DÍEZ

1999-11-01

Full Text Available The precise microenvironment of Paracoccidioides brasiliensis has not yet been discovered perhaps because the methods used are not sensitive enough. We applied to this purpose the polymerase chain reaction (PCR using three sets of specific primers corresponding to two P. brasiliensis genes. This fungus as well as several other fungi, were grown and their DNA obtained by mechanical disruption and a phenol chloroform isoamylalcohol-based purification method. The DNA served for a PCR reaction that employed specific primers from two P. brasiliensis genes that codify for antigenic proteins, namely, the 27 kDa and the 43 kDa. The lowest detection range for the 27 kDa gene was 3 pg. The amplification for both genes was positive only with DNA from P. brasiliensis; additionally, the mRNA for the 27 kDa gene was present only in P. brasiliensis, as indicated by the Northern analysis. The standardization of PCR technology permitted the amplification of P. brasiliensis DNA in artificially contaminated soils and in tissues of armadillos naturally infected with the fungus. These results indicate that PCR technology could play an important role in the search for P. brasiliensis’ habitat and could also be used in other ecological studies.O microambiente adequado do Paracoccidioides brasiliensis não foi ainda bem esclarecido, talvez porque os métodos utilizados não sejam suficientemente sensíveis. Aplicamos com este propósito, a reação em cadeia da polimerase (PCR usando três jogos de primers específicos do P. brasiliensis, correspondendo a dois dos genes do P. brasiliensis. Este fungo, assim como outros fungos, foram cultivados e seus DNAs obtidos por ruptura mecânica e purificados com mistura de fenol-clorofórmio com álcool isoamílico. Os DNAs serviram para a reação de PCR utilizando-se primers específicos para dois dos genes do P. brasiliensis que codificam para as proteínas antigênicas, denominadas, 27 kDa e 43 kDa. O limite mínimo de

Influence of non-adherent yeast cells on electrical characteristics of diamond-based field-effect transistors

Energy Technology Data Exchange (ETDEWEB)

Procházka, Václav, E-mail: prochazkav@fzu.cz [Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, 16627 Prague (Czech Republic); Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10/112, 162 00 Prague (Czech Republic); Cifra, Michal [Institute of Photonics and Electronics, The Czech Academy of Sciences, Chaberská 57, 182 51 Prague (Czech Republic); Kulha, Pavel [Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, 16627 Prague (Czech Republic); Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10/112, 162 00 Prague (Czech Republic); Ižák, Tibor [Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10/112, 162 00 Prague (Czech Republic); Rezek, Bohuslav [Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, 16627 Prague (Czech Republic); Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10/112, 162 00 Prague (Czech Republic); Kromka, Alexander [Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10/112, 162 00 Prague (Czech Republic); Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 16629 Prague (Czech Republic)

2017-02-15

Highlights: • Interaction of non-adherent yeast cells with H-terminated diamond described. • Effect of cell culture solutions on H-diamond SGFET (positive potential shifts). • H-diamond sensitive to metabolic activity of yeast cells (negative potential shift). - Abstract: Diamond thin films provide unique features as substrates for cell cultures and as bio-electronic sensors. Here we employ solution-gated field effect transistors (SGFET) based on nanocrystalline diamond thin films with H-terminated surface which exhibits the sub-surface p-type conductive channel. We study an influence of yeast cells (Saccharomyces cerevisiae) on electrical characteristics of the diamond SGFETs. Two different cell culture solutions (sucrose and yeast peptone dextrose–YPD) are used, with and without the cells. We have found that transfer characteristics of the SGFETs exhibit a negative shift of the gate voltage by −26 mV and −42 mV for sucrose and YPD with cells in comparison to blank solutions without the cells. This effect is attributed to a local pH change in close vicinity of the H-terminated diamond surface due to metabolic processes of the yeast cells. The pH sensitivity of the diamond-based SGFETs, the role of cell and protein adhesion on the gate surface and the role of negative surface charge of yeast cells on the SGFETs electrical characteristics are discussed as well.

Influence of non-adherent yeast cells on electrical characteristics of diamond-based field-effect transistors

International Nuclear Information System (INIS)

Procházka, Václav; Cifra, Michal; Kulha, Pavel; Ižák, Tibor; Rezek, Bohuslav; Kromka, Alexander

2017-01-01

Highlights: • Interaction of non-adherent yeast cells with H-terminated diamond described. • Effect of cell culture solutions on H-diamond SGFET (positive potential shifts). • H-diamond sensitive to metabolic activity of yeast cells (negative potential shift). - Abstract: Diamond thin films provide unique features as substrates for cell cultures and as bio-electronic sensors. Here we employ solution-gated field effect transistors (SGFET) based on nanocrystalline diamond thin films with H-terminated surface which exhibits the sub-surface p-type conductive channel. We study an influence of yeast cells (Saccharomyces cerevisiae) on electrical characteristics of the diamond SGFETs. Two different cell culture solutions (sucrose and yeast peptone dextrose–YPD) are used, with and without the cells. We have found that transfer characteristics of the SGFETs exhibit a negative shift of the gate voltage by −26 mV and −42 mV for sucrose and YPD with cells in comparison to blank solutions without the cells. This effect is attributed to a local pH change in close vicinity of the H-terminated diamond surface due to metabolic processes of the yeast cells. The pH sensitivity of the diamond-based SGFETs, the role of cell and protein adhesion on the gate surface and the role of negative surface charge of yeast cells on the SGFETs electrical characteristics are discussed as well.

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium.

Science.gov (United States)

Smith, I M; Baker, A; Arneborg, N; Jespersen, L

2015-11-01

The human gastrointestinal epithelium makes up the largest barrier separating the body from the external environment. Whereas invasive pathogens cause epithelial barrier disruption, probiotic micro-organisms modulate tight junction regulation and improve epithelial barrier function. In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability of four nonpathogenic yeast species to modulate transepithelial electrical resistance (TER) across a monolayer of differentiated human colonocytes (Caco-2 cells). Further, we assessed yeast modulation of a Salmonella Typhimurium-induced epithelial cell barrier function insult. Our findings demonstrate distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study demonstrates distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Further, our data demonstrate significant yeast-mediated modulation of Salmonella Typhimurium-induced epithelial cell barrier disruption and identify Kluyveromyces marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study is the first to demonstrate significant non-Saccharomyces yeast

Immobilization method of yeast cells for intermittent contact mode imaging using the atomic force microscope

International Nuclear Information System (INIS)

De, Tathagata; Chettoor, Antony M.; Agarwal, Pranav; Salapaka, Murti V.; Nettikadan, Saju

2010-01-01

The atomic force microscope (AFM) is widely used for studying the surface morphology and growth of live cells. There are relatively fewer reports on the AFM imaging of yeast cells (Kasas and Ikai, 1995), (Gad and Ikai, 1995). Yeasts have thick and mechanically strong cell walls and are therefore difficult to attach to a solid substrate. In this report, a new immobilization technique for the height mode imaging of living yeast cells in solid media using AFM is presented. The proposed technique allows the cell surface to be almost completely exposed to the environment and studied using AFM. Apart from the new immobilization protocol, for the first time, height mode imaging of live yeast cell surface in intermittent contact mode is presented in this report. Stable and reproducible imaging over a 10-h time span is observed. A significant improvement in operational stability will facilitate the investigation of growth patterns and surface patterns of yeast cells.

Global Gene Expression Analysis of Yeast Cells during Sake Brewing▿ †

Science.gov (United States)

Wu, Hong; Zheng, Xiaohong; Araki, Yoshio; Sahara, Hiroshi; Takagi, Hiroshi; Shimoi, Hitoshi

2006-01-01

During the brewing of Japanese sake, Saccharomyces cerevisiae cells produce a high concentration of ethanol compared with other ethanol fermentation methods. We analyzed the gene expression profiles of yeast cells during sake brewing using DNA microarray analysis. This analysis revealed some characteristics of yeast gene expression during sake brewing and provided a scaffold for a molecular level understanding of the sake brewing process. PMID:16997994

Unravel lipid accumulation mechanism in oleaginous yeast through single cell systems biology study

Energy Technology Data Exchange (ETDEWEB)

Ding, Shiyou; Xiaoliang, Xie

2017-12-18

Replacement of petroleum with advanced biofuels is critical for environmental protection needs, sustainable and secure energy demands, and economic development. Bacteria, yeasts, and fungi can naturally synthesize fatty acids, isoprenoids, or polyalkanoates for energy storage, and therefore are currently explored for hydrocarbon fuel production. Oleaginous yeasts can accumulate high levels of lipids in the form of triacylglycerols (TAGs) when encountering stress conditions or imbalanced growth (e.g., growing under excess carbon sources and limited nitrogen conditions). Advantages of using oleaginous yeast as cell factories include short duplication time (< 1 hour), high yield of intracellular droplets, and easy scale-up for industrial production. Currently, various oleaginous yeasts (e.g., Yarrowia, Candida, Rhodotorulla, Rhodosporidium, Cryptococcus, Trichosporon, and Lipomyces) have been developed as potential advanced biofuel producers. Oleaginous yeast lipid production has two phases: 1) growth phase, where cells utilize the carbon and nitrogen source to build up biomass. And 2) lipid accumulation phase, where they convert carbon source in media into the storage lipid body. (i.e. a high carbon to nitrogen ratio leads to high lipid production). The lipid production varies dramatically when different sugar, e.g. glucose, xylose is used as carbon source. The efficient utilization of all monomeric sugars of hexoses and pentoses from various lignocellulosic biomass processing approaches is the key for economic lignocellulosic biofuel production. In this project, we explored lipid production in oleaginous yeast under different nitrogen and sugar conditions at the single-cell level. To understand the lipid production mechanism and identify genetic features responsive to lipid accumulation in the presence of pentose and nitrogen, we developed an automated chemical imaging and single-cell transcriptomics method to correlate the lipid accumulation with the

Plasticidade anatômica das folhas de Xylopia brasiliensis Sprengel (Annonaceae Leaf anatomical plasticity of Xylopia brasiliensis Sprengel (Annonaceae

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Cristina Filomena Justo

2005-03-01

Full Text Available A anatomia foliar do gênero Xylopia ainda é pouco explorada. A espécie Xylopia brasiliensis Sprengel, vulgarmente conhecida como pindaíba, ocorre tanto em mata primária como em vegetação modificada num amplo espectro de condições ambientais. O presente estudo descreve algumas características anatômicas da folha de X. brasiliensis e avalia quantitativamente o limbo foliar em função das diferenças ambientais, sazonais e de estatura das plantas. Verificou-se que a espécie apresenta plasticidade anatômica.Leaf anatomy of Xylopia is still poorly explored. The species Xylopia brasiliensis Sprengel, commonly known as pindaíba occurs in primary forest and in modified vegetation in a wide range of environmental conditions. The present study describes some leaf anatomical characteristics of this species and quantitatively evaluates them in function of environmental, seasonal and plant height differences. This species has anatomical plasticity.

Yeast-assisted synthesis of polypyrrole: Quantification and influence on the mechanical properties of the cell wall.

Science.gov (United States)

Andriukonis, Eivydas; Stirke, Arunas; Garbaras, Andrius; Mikoliunaite, Lina; Ramanaviciene, Almira; Remeikis, Vidmantas; Thornton, Barry; Ramanavicius, Arunas

2018-04-01

In this study, the metabolism of yeast cells (Saccharomyces cerevisiae) was utilized for the synthesis of the conducting polymer - polypyrrole (Ppy).Yeast cells were modified in situ by synthesized Ppy. The Ppy was formed in the cell wall by redox-cycling of [Fe(CN) 6 ] 3-/4- , performed by the yeast cells. Fluorescence microscopy, enzymatic digestions, atomic force microscopy and isotope ratio mass spectroscopy were applied to determine both the polymerization reaction itself and the polymer location in yeast cells. Ppy formation resulted in enhanced resistance to lytic enzymes, significant increase of elasticity and alteration of other mechanical cell wall properties evaluated by atomic force microscopy (AFM). The suggested method of polymer synthesis allows the introduction of polypyrrole structures within the cell wall, which is build up from polymers consisting of carbohydrates. This cell wall modification strategy could increase the usefulness of yeast as an alternative energy source in biofuel cells, and in cell based biosensors. Copyright © 2018 Elsevier B.V. All rights reserved.

Stable current outputs and phytate degradation by yeast-based biofuel cell.

Science.gov (United States)

Hubenova, Yolina; Georgiev, Danail; Mitov, Mario

2014-09-01

In this paper, we report for the first time that Candida melibiosica 2491 yeast strain expresses enhanced phytase activity when used as a biocatalyst in biofuel cells. The polarization also results in an increase of the yeast biomass. Higher steady-state electrical outputs, assigned to earlier production of an endogenous mediator, were achieved at continuous polarization under constant load. The obtained results prove that the C. melibiosica yeast-based biofuel cell could be used for simultaneous electricity generation and phytate bioremediation. In addition, the higher phytase activity obtained by interruptive polarization suggests a new method for increasing the phytase yield from microorganisms. Copyright © 2014 John Wiley & Sons, Ltd.

CDNA library from the Latex of Hevea brasiliensis

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Wilaiwan Chotigeat

2010-12-01

Full Text Available Latex from Hevea brasiliensis contains 30-50% (w/w of natural rubber (cis-1,4-polyisoprene, the important rawmaterial for many rubber industries. We have constructed a cDNA library from the latex of H. brasiliensis to investigate theexpressed genes and molecular events in the latex. We analyzed 412 expressed sequence tags (ESTs. More than 90% of theEST clones showed homology to previously described sequences in public databases. Functional classification of the ESTsshowed that the largest category were proteins of unknown function (30.1%, 11.4% of ESTs encoded for rubber synthesisrelatedproteins (RS and 8.5% for defense or stress related proteins (DS. Those with no significant homology to knownsequences (NSH accounted for 8.7%, primary metabolism (PM and gene expression and RNA metabolism were 7.8% and6.6%, respectively. Other categories included, protein synthesis-related proteins (6.6%, chromatin and DNA metabolism(CDM 3.9%, energy metabolism (EM 3.4%, cellular transport (CT 3.2%, cell structure (CS 3.2%, signal transduction (ST2.2%, secondary metabolism (SM 1.7%, protein fate (PF 2.2%, and reproductive proteins (RP 0.7%.

Detection of Anti-Paracoccidioides brasiliensis antibodies in suspected tuberculosis patients = Detecção de anticorpos anti-Paracoccidioides brasiliensis em pacientes suspeitos de tuberculose

Directory of Open Access Journals (Sweden)

Maria Luiza Dias Fraga Peron

2010-07-01

Full Text Available Paracoccidioidomycosis (PCM is an important systemic mycosis in LatinAmerica that occurs as active disease in 1-2% of Paracoccidioides brasiliensis infected people. Like PCM, tuberculosis (TB affects mainly the lungs and the clinical and radiological aspects do notalways allow differentiation between them. The aim of this study was to carry out serological investigation for detecting anti-P. brasiliensis antibodies, by three serological methods, in patientswith symptoms suggestive of pulmonary TB. From August 2005 to September 2006, 76 patients with pulmonary symptoms suspected for TB were attended at the Regional Specialties Center Laboratory in the city of Paranavaí, Paraná, Brazil and submitted to microbiological TB research, ELISA, immunodiffusion and immunoblotting for PCM. Of all the individuals, 21 (27.63% were reactive to P. brasiliensis by ELISA and 11 (14.47% showed a laboratory diagnosis of pulmonary TB. Of all the individuals serologically reactive to P. brasiliensis, by ELISA, none had positive results by immunodiffusion and one reacted with antigen 43 kDa when Immunobloting was carried out. Our results lead us to reflect a necessity to obtain a more specific serologic test for diagnosis of PCM disease in patients with respiratory symptoms considering the high number of individuals reactive to P. brasiliensis especially in endemic areas.Paracoccidioidomicose (PCM é importante micose sistêmica na América Latina, que ocorre como doença ativa em 1-2% dos indivíduos infectados com Paracoccidioides brasiliensis. Assim como a PCM, a tuberculose (TB afeta principalmente os pulmões, porém os aspectos clínicos e radiológicos nem sempre permitem a diferenciação entreessas doenças. O objetivo deste estudo foi realizar um inquérito sorológico para a detecção de anticorpos anti-P. brasiliensis, utilizando três métodos sorológicos, em pacientes com sintomassugestivos de tuberculose pulmonar. De agosto de 2005 a setembro de

Paracoccidioides brasilienses isolates obtained from patients with acute and chronic disease exhibit morphological differences after animal passage

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SVIDZINSKI Terezinha Inez Estivalet

1999-01-01

Full Text Available The basis for virulence in Paracoccidioides brasiliensis is not completely understood. There is a consensus that the sequencial in vitro subcultivation of P. brasiliensis leads to loss of its pathogenicity, which can be reverted by reisolation from animal passage. Attention to morphological and biochemical properties that are regained or demonstrated after animal passage may provide new insights into factors related to the pathogenicity and virulence of P. brasiliensis. We evaluated morphological characters: the percentage of budding cells, number of buds by cell and the diameter of 100 mother cells of yeast-like cells of 30 P. brasiliensis isolates, before and after animal passage. The isolates were obtained from patients with different clinical forms of paracoccidioidomycosis (PCM: acute form (group A, n=15 and chronic form (group C, n=15. The measurement of the yeast cell sizes was carried out with the aid of an Olympus CBB microscope coupled with a micrometer disc. We measured the major transverse and longitudinal axes of 100 viable cells of each preparation. The percentage of budding cells as also the number of buds by cell was not influenced by animal passage, regardless of the source of the strain (acute or chronic groups. The size values of P. brasiliensis isolates from groups A and C, measured before the animal passage exhibited the same behavior. After animal passage, there was a statistically significant difference between the cell sizes of P. brasiliensis isolates recovered from testicles inoculated with strains from groups A and C. The maximum diameter of mother cells from group A isolates exhibited a size of 42.1mm in contrast with 32.9mm exhibited by mother cells from group C (p<0.05. The diameter of 1500 mother cells from group A isolates exhibited a medium size of 16.0mm (SD ± 4.0, a value significantly higher than the 14.1mm (SD = ± 3.3 exhibited by 1500 mother cells from group C isolates (p<0.05. Our results reinforce the

Geographic variation in ectoparasitic mites diversity in Tadarida Brasiliensis (Chiroptera, Molossidae

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Tatiana C. Pesenti

2014-12-01

Full Text Available Tadarida brasiliensis (Geoffroy, 1824, the Brazilian free-tailed bat, is an insectivorous bat that occurs from southern United States of America to southern South America. In this study we present the first data on diversity of ectoparasitic mites of T. brasiliensis in Brazil. A compilation and analysis of the studies of mite diversity conducted in different points the geographic distribution this bat species are provided. The mites were collected from March 2010 to November 2011 on 160 T. brasiliensis adult bats captured in southern Brazil. Four species of mites have been found: Chiroptonyssus robustipes (Ewing, 1925, Ewingana longa (Ewing, 1938, Ewingana inaequalis (Radford, 1948, and specimens of Cheyletidae. Chiroptonyssus robustipes was the most prevalent species (100%, followed by E. longa (20%, E. inaequalis (10%, and specimens of Cheyletidae (1.25%. The data currently available show that C. robustipes parasitizes T. brasiliensis throughout its region of occurrence, and this mite is highly prevalent and abundant. The two species of Ewingana accompany the geographical distribution of T. brasiliensis, but with much lower prevalence and abundance.

Different characteristics between menadione and menadione sodium bisulfite as redox mediator in yeast cell suspension

OpenAIRE

Yamashoji, Shiro

2016-01-01

Menadione promoted the production of active oxygen species (AOS) in both yeast cell suspension and the crude enzymes from the cells, but menadione sodium bisulfite (MSB) had little effect on the production of AOS in the cell suspension. MSB kept the stable increase in the electron transfer from intact yeast cells to anode compared to menadione, but the electron transfer promoted by MSB was inhibited in permeabilized yeast cell suspension. Menadione promoted oxidation of NAD(P)H much faster th...

An immunoproteomic approach revealing peptides from Sporothrix brasiliensis that induce a cellular immune response in subcutaneous sporotrichosis.

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de Almeida, José Roberto Fogaça; Jannuzzi, Grasielle Pereira; Kaihami, Gilberto Hideo; Breda, Leandro Carvalho Dantas; Ferreira, Karen Spadari; de Almeida, Sandro Rogério

2018-03-08

Sporothrix brasiliensis is the most virulent fungus of the Sporothrix complex and is the main species recovered in the sporotrichosis zoonotic hyperendemic area in Rio de Janeiro. A vaccine against S. brasiliensis could improve the current sporotrichosis situation. Here, we show 3 peptides from S. brasiliensis immunogenic proteins that have a higher likelihood for engaging MHC-class II molecules. We investigated the efficiency of the peptides as vaccines for preventing subcutaneous sporotrichosis. In this study, we observed a decrease in lesion diameters in peptide-immunized mice, showing that the peptides could induce a protective immune response against subcutaneous sporotrichosis. ZR8 peptide is from the GP70 protein, the main antigen of the Sporothrix complex, and was the best potential vaccine candidate by increasing CD4 + T cells and higher levels of IFN-γ, IL-17A and IL-1β characterizing a strong cellular immune response. This immune environment induced a higher number of neutrophils in lesions that are associated with fungus clearance. These results indicated that the ZR8 peptide induces a protective immune response against subcutaneous sporotrichosis and is a vaccine candidate against S. brasiliensis infection.

Magnesium affects rubber biosynthesis and particle stability in Ficus elastica, Hevea brasiliensis and Parthenium argentatum

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Natural rubber biosynthesis occurs in laticifers of Ficus elastica and Hevea brasiliensis, and in parenchyma cells of Parthenium argentatum. Natural rubber is synthesized by rubber transferase using allylic pyrophosphates as initiators, isopentenyl pyrophosphate as monomeric substrate and magnesium ...

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

Science.gov (United States)

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

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. PMID:22768320

Content of endogenous thiols and radioresistance of gemmating cells of Saccharomyces ellipsoideus and Saccharomyces cerevisiale yeasts

International Nuclear Information System (INIS)

Simonyan, N.V.; Avakyan, Ts.M.; Dzhanpoladyan, N.L.; Stepanyan, L.G.

1983-01-01

It has been shown that gemmating cells of ''wild type'' yeasts are more radioresistant and contain more endogenous thiols, than resting cells. Gemmating cells of Saccharomyces cerevisial yeasts, carrying the mutation rad 51, as to radioresistance and content of SH groups do not differ from resting cells. The results obtained testify to a connec-- tion between increased radioresistance of the yeast gemmating cells and increased content of endogenous thiols in them

Scanning electrochemical microscopy of menadione-glutathione conjugate export from yeast cells

Science.gov (United States)

Mauzeroll, Janine; Bard, Allen J.

2004-01-01

The uptake of menadione (2-methyl-1,4-naphthoquinone), which is toxic to yeast cells, and its expulsion as a glutathione complex were studied by scanning electrochemical microscopy. The progression of the in vitro reaction between menadione and glutathione was monitored electrochemically by cyclic voltammetry and correlated with the spectroscopic (UV–visible) behavior. By observing the scanning electrochemical microscope tip current of yeast cells suspended in a menadione-containing solution, the export of the conjugate from the cells with time could be measured. Similar experiments were performed on immobilized yeast cell aggregates stressed by a menadione solution. From the export of the menadione-glutathione conjugate detected at a 1-μm-diameter electrode situated 10 μm from the cells, a flux of about 30,000 thiodione molecules per second per cell was extracted. Numerical simulations based on an explicit finite difference method further revealed that the observation of a constant efflux of thiodione from the cells suggested the rate was limited by the uptake of menadione and that the efflux through the glutathione-conjugate pump was at least an order of magnitude faster. PMID:15148374

Mitochondrial import of human and yeast fumarase in live mammalian cells: Retrograde translocation of the yeast enzyme is mainly caused by its poor targeting sequence

International Nuclear Information System (INIS)

Singh, Bhag; Gupta, Radhey S.

2006-01-01

Studies on yeast fumarase provide the main evidence for dual localization of a protein in mitochondria and cytosol by means of retrograde translocation. We have examined the subcellular targeting of yeast and human fumarase in live cells to identify factors responsible for this. The cDNAs for mature yeast or human fumarase were fused to the gene for enhanced green fluorescent protein (eGFP) and they contained, at their N-terminus, a mitochondrial targeting sequence (MTS) derived from either yeast fumarase, human fumarase, or cytochrome c oxidase subunit VIII (COX) protein. Two nuclear localization sequences (2x NLS) were also added to these constructs to facilitate detection of any cytosolic protein by its targeting to nucleus. In Cos-1 cells transfected with these constructs, human fumarase with either the native or COX MTSs was detected exclusively in mitochondria in >98% of the cells, while the remainder 1-2% of the cells showed varying amounts of nuclear labeling. In contrast, when human fumarase was fused to the yeast MTS, >50% of the cells showed nuclear labeling. Similar studies with yeast fumarase showed that with its native MTS, nuclear labeling was seen in 80-85% of the cells, but upon fusion to either human or COX MTS, nuclear labeling was observed in only 10-15% of the cells. These results provide evidence that extramitochondrial presence of yeast fumarase is mainly caused by the poor mitochondrial targeting characteristics of its MTS (but also affected by its primary sequence), and that the retrograde translocation mechanism does not play a significant role in the extramitochondrial presence of mammalian fumarase

Expression of death receptor 4 induces caspase-independent cell death in MMS-treated yeast.

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Kang, Mi-Sun; Lee, Sung-Keun; Park, Chang-Shin; Kang, Ju-Hee; Bae, Sung-Ho; Yu, Sung-Lim

2008-11-14

DR4, a tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, is a key element in the extrinsic pathway of TRAIL/TRAIL receptor-related apoptosis that exerts a preferential toxic effect against tumor cells. However, TRAIL and DR4 are expressed in various normal cells, and recent studies indicate that DR4 has a number of non-apoptotic functions. In this study, we evaluated the effects of human DR4 expression in yeast to determine the function of DR4 in normal cells. The expression of DR4 in yeast caused G1 arrest, which resulted in transient growth inhibition. Moreover, treatment of DR4-expressing yeast with a DNA damaging agent, MMS, elicited drastic, and sustained cell growth inhibition accompanied with massive apoptotic cell death. Further analysis revealed that cell death in the presence of DNA damage and DR4 expression was not dependent on the yeast caspase, YCA1. Taken together, these results indicate that DR4 triggers caspase-independent programmed cell death during the response of normal cells to DNA damage.

Yeast for virus research

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Zhao, Richard Yuqi

2017-01-01

Budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are two popular model organisms for virus research. They are natural hosts for viruses as they carry their own indigenous viruses. Both yeasts have been used for studies of plant, animal and human viruses. Many positive sense (+) RNA viruses and some DNA viruses replicate with various levels in yeasts, thus allowing study of those viral activities during viral life cycle. Yeasts are single cell eukaryotic organisms. Hence, many of the fundamental cellular functions such as cell cycle regulation or programed cell death are highly conserved from yeasts to higher eukaryotes. Therefore, they are particularly suited to study the impact of those viral activities on related cellular activities during virus-host interactions. Yeasts present many unique advantages in virus research over high eukaryotes. Yeast cells are easy to maintain in the laboratory with relative short doubling time. They are non-biohazardous, genetically amendable with small genomes that permit genome-wide analysis of virologic and cellular functions. In this review, similarities and differences of these two yeasts are described. Studies of virologic activities such as viral translation, viral replication and genome-wide study of virus-cell interactions in yeasts are highlighted. Impacts of viral proteins on basic cellular functions such as cell cycle regulation and programed cell death are discussed. Potential applications of using yeasts as hosts to carry out functional analysis of small viral genome and to develop high throughput drug screening platform for the discovery of antiviral drugs are presented. PMID:29082230

Cell biology of homologous recombination in yeast

DEFF Research Database (Denmark)

Eckert-Boulet, Nadine Valerie; Rothstein, Rodney; Lisby, Michael

2011-01-01

Homologous recombination is an important pathway for error-free repair of DNA lesions, such as single- and double-strand breaks, and for rescue of collapsed replication forks. Here, we describe protocols for live cell imaging of single-lesion recombination events in the yeast Saccharomyces...

Research of aquatic organism addition influence on the reproduction of yeast cells in the dough

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Дмитро Павлович Крамаренко

2016-12-01

Full Text Available The analysis of the research results of influence of various amounts of aquatic organism additions on the reproduction of yeast cells is given. A positive impact of aquatic organism addition of animal and plant origin in investigated quantities on the reproduction of yeast cells is revealed. The influence of the chemical composition of the aquatic organism additives on the reproduction of yeast cells is proved

An optimized one-tube, semi-nested PCR assay for Paracoccidioides brasiliensis detection.

Science.gov (United States)

Pitz, Amanda de Faveri; Koishi, Andrea Cristine; Tavares, Eliandro Reis; Andrade, Fábio Goulart de; Loth, Eduardo Alexandre; Gandra, Rinaldo Ferreira; Venancio, Emerson José

2013-01-01

Herein, we report a one-tube, semi-nested-polymerase chain reaction (OTsn-PCR) assay for the detection of Paracoccidioides brasiliensis. We developed the OTsn-PCR assay for the detection of P. brasiliensis in clinical specimens and compared it with other PCR methods. The OTsn-PCR assay was positive for all clinical samples, and the detection limit was better or equivalent to the other nested or semi-nested PCR methods for P. brasiliensis detection. The OTsn-PCR assay described in this paper has a detection limit similar to other reactions for the molecular detection of P. brasiliensis, but this approach is faster and less prone to contamination than other conventional nested or semi-nested PCR assays.

A Comparative Study of the Cell Wall Structure of Basidiomycetous and Related Yeasts

NARCIS (Netherlands)

Kreger-van Rij, N.J.W.; Veenhuis, M.

1971-01-01

The wall of basidiomycetous and related yeasts showed a lamellar structure in sections of both budding cells and hyphae fixed with potassium permanganate. The yeasts also had a typical way of bud formation and septation. These features differ from those recorded for ascomycetous yeasts. In the

Synthetic yeast based cell factories for vanillin-glucoside production

DEFF Research Database (Denmark)

Strucko, Tomas

and controlled expression/overexpression of genes of interest. De novo biosynthetic pathway for vanillin-β-glucoside production was employed as a model system for several case studies in this project. In order to construct yeast cell factories fulfilling current demands of industrial biotechnology, methods......The yeast Saccharomyces cerevisiae is well a characterized microorganism and widely used as eukaryotic model organism as well as a key cell factory for bioproduction of various products. The latter comprise a large variety of scientifically and industrially relevant products such as low-value bulk...... chemicals and biofuels, food additives, high-value chemicals and recombinant proteins. Despite the recent achievements in the fields of systems biology and metabolic engineering together with availability of broad genetic engineering toolbox, the full potential of S. cerevisiae as a cell factory is not yet...

Succinic acid production by Actinobacillus succinogenes using hydrolysates of spent yeast cells and corn fiber.

Science.gov (United States)

Chen, Ke-Quan; Li, Jian; Ma, Jiang-Feng; Jiang, Min; Wei, Ping; Liu, Zhong-Min; Ying, Han-Jie

2011-01-01

The enzymatic hydrolysate of spent yeast cells was evaluated as a nitrogen source for succinic acid production by Actinobacillus succinogenes NJ113, using corn fiber hydrolysate as a carbon source. When spent yeast cell hydrolysate was used directly as a nitrogen source, a maximum succinic acid concentration of 35.5 g/l was obtained from a glucose concentration of 50 g/l, with a glucose utilization of 95.2%. Supplementation with individual vitamins showed that biotin was the most likely factor to be limiting for succinic acid production with spent yeast cell hydrolysate. After supplementing spent yeast cell hydrolysate and 90 g/l of glucose with 150 μg/l of biotin, cell growth increased 32.5%, glucose utilization increased 37.6%, and succinic acid concentration was enhanced 49.0%. As a result, when biotin-supplemented spent yeast cell hydrolysate was used with corn fiber hydrolysate, a succinic acid yield of 67.7% was obtained from 70.3 g/l of total sugar concentration, with a productivity of 0.63 g/(l h). Our results suggest that biotin-supplemented spent yeast cell hydrolysate may be an alternative nitrogen source for the efficient production of succinic acid by A. succinogenes NJ113, using renewable resources. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

In-silico gene co-expression network analysis in Paracoccidioides brasiliensis with reference to haloacid dehalogenase superfamily hydrolase gene

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Raghunath Satpathy

2015-01-01

Full Text Available Context: Paracoccidioides brasiliensis, a dimorphic fungus is the causative agent of paracoccidioidomycosis, a disease globally affecting millions of people. The haloacid dehalogenase (HAD superfamily hydrolases enzyme in the fungi, in particular, is known to be responsible in the pathogenesis by adhering to the tissue. Hence, identification of novel drug targets is essential. Aims: In-silico based identification of co-expressed genes along with HAD superfamily hydrolase in P. brasiliensis during the morphogenesis from mycelium to yeast to identify possible genes as drug targets. Materials and Methods: In total, four datasets were retrieved from the NCBI-gene expression omnibus (GEO database, each containing 4340 genes, followed by gene filtration expression of the data set. Further co-expression (CE study was performed individually and then a combination these genes were visualized in the Cytoscape 2. 8.3. Statistical Analysis Used: Mean and standard deviation value of the HAD superfamily hydrolase gene was obtained from the expression data and this value was subsequently used for the CE calculation purpose by selecting specific correlation power and filtering threshold. Results: The 23 genes that were thus obtained are common with respect to the HAD superfamily hydrolase gene. A significant network was selected from the Cytoscape network visualization that contains total 7 genes out of which 5 genes, which do not have significant protein hits, obtained from gene annotation of the expressed sequence tags by BLAST X. For all the protein PSI-BLAST was performed against human genome to find the homology. Conclusions: The gene co-expression network was obtained with respect to HAD superfamily dehalogenase gene in P. Brasiliensis.

Genetic control of yeast cell radiosensitivity modification by oxygen and hypoxic sensitizers

International Nuclear Information System (INIS)

Zhuranovskaya, G.P.; Petin, V.G.

1984-01-01

Diploid yeast cells Saccharomyces cerevisiae ''of the wild type'', individual mutants, homozygous in rad 2 and rad 54 and double mutants, containing both these loci in homozygous state are considered to prove genetic determination of radiosensitivity modification of hypoxic cells by oxygen and electron acceptor compounds previously demonstrated on yeast cells of other genotypes. It is shown that both ''oxygen effect'' and the effect of hypoxic sensitizers depend on the activity of repair systems. The possible mechanism of participation of post-radiation restoration processes in the modification of cell radiosensitivity, is discussed

An optimized one-tube, semi-nested PCR assay for Paracoccidioides brasiliensis detection

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Amanda de Faveri Pitz

2013-12-01

Full Text Available Introduction Herein, we report a one-tube, semi-nested-polymerase chain reaction (OTsn-PCR assay for the detection of Paracoccidioides brasiliensis. Methods We developed the OTsn-PCR assay for the detection of P. brasiliensis in clinical specimens and compared it with other PCR methods. Results The OTsn-PCR assay was positive for all clinical samples, and the detection limit was better or equivalent to the other nested or semi-nested PCR methods for P. brasiliensis detection. Conclusions The OTsn-PCR assay described in this paper has a detection limit similar to other reactions for the molecular detection of P. brasiliensis, but this approach is faster and less prone to contamination than other conventional nested or semi-nested PCR assays.

Monitoring of yeast cell concentration using a micromachined impedance sensor

NARCIS (Netherlands)

Krommenhoek, E.E.; Gardeniers, Johannes G.E.; Bomer, Johan G.; van den Berg, Albert; Li, X.; Ottens, M.; van der Wielen, L.A.M.; van Dedem, G.W.K.; van Leeuwen, M.; van Gulik, W.M.; Heijnen, J.J.

2005-01-01

The paper describes the design, modelling and experimental characterization of a micromachined impedance sensor for on-line monitoring of the viable yeast cell concentration (biomass) in a miniaturized cell assay. Measurements in a Saccharomyces cerevisiae cell culture show that the permittivity of

Cell dualism: presence of cells with alternative membrane potentials in growing populations of bacteria and yeasts.

Science.gov (United States)

Ivanov, Volodymyr; Rezaeinejad, Saeid; Chu, Jian

2013-10-01

It is considered that all growing cells, for exception of acidophilic bacteria, have negatively charged inside cytoplasmic membrane (Δψ⁻-cells). Here we show that growing populations of microbial cells contain a small portion of cells with positively charged inside cytoplasmic membrane (Δψ⁺-cells). These cells were detected after simultaneous application of the fluorescent probes for positive membrane potential (anionic dye DIBAC⁻) and membrane integrity (propidium iodide, PI). We found in exponentially growing cell populations of Escherichia coli and Saccharomyces cerevisiae that the content of live Δψ⁻-cells was 93.6 ± 1.8 % for bacteria and 90.4 ± 4.0 % for yeasts and the content of live Δψ⁺-cells was 0.9 ± 0.3 % for bacteria and 2.4 ± 0.7 % for yeasts. Hypothetically, existence of Δψ⁺-cells could be due to short-term, about 1 min for bacteria and 5 min for yeasts, change of membrane potential from negative to positive value during the cell cycle. This change has been shown by the reversions of K⁺, Na⁺, and Ca²⁺ ions fluxes across the cell membrane during synchronous yeast culture. The transformation of Δψ(⁻-cells to Δψ⁺-cells can be explained by slow influx of K⁺ ions into Δψ⁻-cell to the trigger level of K⁺ concentration ("compression of potassium spring"), which is forming "alternative" Δψ⁺-cell for a short period, following with fast efflux of K⁺ ions out of Δψ⁺-cell ("release of potassium spring") returning cell to normal Δψ⁻ state. We anticipate our results to be a starting point to reveal the biological role of cell dualism in form of Δψ⁻- and Δψ⁺- cells.

Agaricus brasiliensis (sun mushroom) affects the expression of genes related to cholesterol homeostasis.

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de Miranda, Aline Mayrink; Rossoni Júnior, Joamyr Victor; Souza E Silva, Lorena; Dos Santos, Rinaldo Cardoso; Silva, Marcelo Eustáquio; Pedrosa, Maria Lúcia

2017-06-01

The sun mushroom (Agaricus brasiliensis) is considered a major source of bioactive compounds with potential health benefits. Mushrooms typically act as lipid-lowering agents; however, little is known about the mechanisms of action of A. brasiliensis in biological systems. This study aimed to determine the underlying mechanism involved in the cholesterol-lowering effect of A. brasiliensis through the assessment of fecal and serum lipid profiles in addition to gene expression analysis of specific transcription factors, enzymes, and transporters involved in cholesterol homeostasis. Twenty-four albino Fischer rats approximately 90 days old, with an average weight of 205 g, were divided into four groups of 6 each and fed a standard AIN-93 M diet (C), hypercholesterolemic diet (H), hypercholesterolemic diet +1 % A. brasiliensis (HAb), or hypercholesterolemic diet +0.008 % simvastatin (HS) for 6 weeks. Simvastatin was used as a positive control, as it is a typical drug prescribed for lipid disorders. Subsequently, blood, liver, and feces samples were collected for lipid profile and quantitative real-time polymerase chain reaction gene expression analyses. Diet supplementation with A. brasiliensis significantly improved serum lipid profiles, comparable to the effect observed for simvastatin. In addition, A. brasiliensis dietary supplementation markedly promoted fecal cholesterol excretion. Increased expression of 7α-hydroxylase (CYP7A1), ATP-binding cassette subfamily G-transporters (ABCG5/G8), and low-density lipoprotein receptor (LDLR) was observed following A. brasiliensis administration. Our results suggest that consumption of A. brasiliensis improves the serum lipid profile in hypercholesterolemic rats by modulating the expression of key genes involved in hepatic cholesterol metabolism.

Study of the role of the covalently linked cell wall protein (Ccw14p) and yeast glycoprotein (Ygp1p) within biofilm formation in a flor yeast strain.

Science.gov (United States)

Moreno-García, J; Coi, A L; Zara, G; García-Martínez, T; Mauricio, J C; Budroni, M

2018-03-01

Flor yeasts are Saccharomyces cerevisiae strains noted by their ability to create a type of biofilm in the air-liquid interface of some wines, known as 'flor' or 'velum', for which certain proteins play an essential role. Following a proteomic study of a flor yeast strain, we deleted the CCW14 (covalently linked cell wall protein) and YGP1 (yeast glycoprotein) genes-codifying for two cell surface glycoproteins-in a haploid flor yeast strain and we reported that both influence the weight of the biofilm as well as cell adherence (CCW14).

Increased genome instability is not accompanied by sensitivity to DNA damaging agents in aged yeast cells

NARCIS (Netherlands)

Novarina, Daniele; Mavrova, Sara N.; Janssens, Georges E.; Rempel, Irina L.; Veenhoff, Liesbeth M.; Chang, Michael

The budding yeast Saccharomyces cerevisiae divides asymmetrically, producing a new daughter cell from the original mother cell. While daughter cells are born with a full lifespan, a mother cell ages with each cell division and can only generate on average 25 daughter cells before dying. Aged yeast

Construction of a Nocardia brasiliensis fluorescent plasmid to study Actinomycetoma pathogenicity.

Science.gov (United States)

Salinas-Carmona, Mario C; Rocha-Pizaña, María R

2011-01-01

Nocardia brasiliensis, is a bacteria that lives as saprophyte in soil and causes a disease called actinomycetoma in both human and animals. Nocardia brasiliensis is an intracellular, facultative bacterium that replicates and survives within host macrophages. The mechanisms involved in the evasion of the microbicidal actions of macrophages remain unclear. The filamentous growth of N. brasiliensis is resistant to unicellular preparations, leading to inaccurate quantification of bacterial numbers by means of colony forming units (CFU). As successful survival studies with green fluorescent protein (GFP)-expressing bacterial strains have been reported, we constructed a recombinant GFP-expressing strain of N. brasiliensis. The virulence of the modified strain is maintained because it induces mycetoma in BALB/c mice. This new strain can be used for bacterial survival assays using cytometry and to elucidate the pathogenicity mechanisms in Actinomycetoma infection. Copyright © 2010 Elsevier Inc. All rights reserved.

Morfoanatomia vegetativa de Opuntia brasiliensis (Willd Haw / Vegetative morphology and anatomy of Opuntia brasiliensis (Willd Haw

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Camila Firmino de Azevedo

2013-01-01

Full Text Available Opuntia brasiliensis (Willd Haw. é uma Cactaceae nativa do Brasil utilizada como ornamental, que apresenta caracteres morfológicos semelhantes a outras espécies do gênero, o que dificulta sua identificação. Dessa forma, foi realizado uma descrição morfoanatômica de O. brasiliensis com o objetivo de ampliar o conhecimento sobre a organização estrutural do gênero e fornecer subsídios para a identificação da espécie, bem como observar caracteres importantes na adaptação a ambientes xerófilos. Foram feitas secções transversais e paradérmicas da raiz, caule principal e cladódios com espécimes coletados na zona rural da cidade de Serra Branca (PB, localizada na região do cariri ocidental. O. brasiliensis apresenta raiz ramificada e caule clorofilado formando um eixo principal de onde partem inúmeros cladódios delgados. Observamse pelos e epiderme unisseriada irregular na raiz, que possui córtex formado por parênquima, seguido de endoderme multisseriada e periciclo. No cilindro central da raiz, ocorrem tecidos vasculares formando cinco pólos seguidos de medula. O caule e o cladódio apresentam epiderme com paredes sinuosas, em que encontram-se estômatos paralelocíticos que apresentam câmara subestomática; e na camada subsequente, hipoderme com grande quantidade de drusas de oxalato de cálcio. O córtex é formado por parênquimas clorofiliano e aquífero, onde observam-se feixes vasculares, com raios de floema voltados para o lado externo, seguido de xilema helicoidal. Porém, nos cladódios, o parênquima clorofiliano é bem mais denso e os feixes vasculares são dispostos irregularmente, enquanto no caule estão distribuídos no sentido radial. O. brasiliensis apresenta várias características importantes na sua identificação, bem como adaptações estruturais a ambientes xerófilos

Measuring strand discontinuity-directed mismatch repair in yeast Saccharomyces cerevisiae by cell-free nuclear extracts.

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Yuan, Fenghua; Lai, Fangfang; Gu, Liya; Zhou, Wen; El Hokayem, Jimmy; Zhang, Yanbin

2009-05-01

Mismatch repair corrects biosynthetic errors generated during DNA replication, whose deficiency causes a mutator phenotype and directly underlies hereditary non-polyposis colorectal cancer and sporadic cancers. Because of remarkably high conservation of the mismatch repair machinery between the budding yeast (Saccharomyces cerevisiae) and humans, the study of mismatch repair in yeast has provided tremendous insights into the mechanisms of this repair pathway in humans. In addition, yeast cells possess an unbeatable advantage over human cells in terms of the easy genetic manipulation, the availability of whole genome deletion strains, and the relatively low cost for setting up the system. Although many components of eukaryotic mismatch repair have been identified, it remains unclear if additional factors, such as DNA helicase(s) and redundant nuclease(s) besides EXO1, participate in eukaryotic mismatch repair. To facilitate the discovery of novel mismatch repair factors, we developed a straightforward in vitro cell-free repair system. Here, we describe the practical protocols for preparation of yeast cell-free nuclear extracts and DNA mismatch substrates, and the in vitro mismatch repair assay. The validity of the cell-free system was confirmed by the mismatch repair deficient yeast strain (Deltamsh2) and the complementation assay with purified yeast MSH2-MSH6.

Mitochondrial fission proteins regulate programmed cell death in yeast

OpenAIRE

Fannjiang, Yihru; Cheng, Wen-Chih; Lee, Sarah J.; Qi, Bing; Pevsner, Jonathan; McCaffery, J. Michael; Hill, R. Blake; Basañez, Gorka; Hardwick, J. Marie

2004-01-01

The possibility that single-cell organisms undergo programmed cell death has been questioned in part because they lack several key components of the mammalian cell death machinery. However, yeast encode a homolog of human Drp1, a mitochondrial fission protein that was shown previously to promote mammalian cell death and the excessive mitochondrial fragmentation characteristic of apoptotic mammalian cells. In support of a primordial origin of programmed cell death involving mitochondria, we fo...

Activity of novel oxazolidinones against Nocardia brasiliensis growing within THP-1 macrophages.

Science.gov (United States)

Vera-Cabrera, Lucio; Espinoza-González, Nelly A; Welsh, Oliverio; Ocampo-Candiani, Jorge; Castro-Garza, Jorge

2009-11-01

Nocardia are organisms that can escape the effects of both immune response and antimicrobial agents, due to their potential capacity to grow intracellularly. In previous studies, we found that experimental oxazolidinones, DA-7157 and DA-7218, are active both in vitro and in vivo. In this study, we compare the ability of linezolid, DA-7157 and DA-7218 to inhibit intracellular growth of Nocardia brasiliensis within the human monocyte cell line THP-1. The addition of oxazolidinones to the infected macrophage monolayer at concentrations 0.25x, 1x, 4x and 16x the MIC for N. brasiliensis resulted in an inhibitory effect on bacterial growth as follows DA-7157 > or = DA-7218 > linezolid. The excellent intracellular antimicrobial activity detected suggests that these compounds could be effective in the treatment of actinomycetoma. However, more studies are needed both in vitro and in vivo, including clinical trials, to confirm this issue.

Phylogenetic analysis reveals a high prevalence of Sporothrix brasiliensis in feline sporotrichosis outbreaks.

Science.gov (United States)

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

2013-01-01

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 (EF1α) 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.

The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

International Nuclear Information System (INIS)

Nishimura, Akira; Kawahara, Nobuhiro; Takagi, Hiroshi

2013-01-01

Highlights: ► NO is produced from L-arginine in response to elevated temperature in yeast. ► Tah18 was first identified as the yeast protein involved in NO synthesis. ► Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe–S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

Analysis of ribosomal RNA stability in dead cells of wine yeast by quantitative PCR.

Science.gov (United States)

Sunyer-Figueres, Merce; Wang, Chunxiao; Mas, Albert

2018-04-02

During wine production, some yeasts enter a Viable But Not Culturable (VBNC) state, which may influence the quality and stability of the final wine through remnant metabolic activity or by resuscitation. Culture-independent techniques are used for obtaining an accurate estimation of the number of live cells, and quantitative PCR could be the most accurate technique. As a marker of cell viability, rRNA was evaluated by analyzing its stability in dead cells. The species-specific stability of rRNA was tested in Saccharomyces cerevisiae, as well as in three species of non-Saccharomyces yeast (Hanseniaspora uvarum, Torulaspora delbrueckii and Starmerella bacillaris). High temperature and antimicrobial dimethyl dicarbonate (DMDC) treatments were efficient in lysing the yeast cells. rRNA gene and rRNA (as cDNA) were analyzed over 48 h after cell lysis by quantitative PCR. The results confirmed the stability of rRNA for 48 h after the cell lysis treatments. To sum up, rRNA may not be a good marker of cell viability in the wine yeasts that were tested. Copyright © 2018 Elsevier B.V. All rights reserved.

The effect of Agaricus brasiliensis extract supplementation on honey bee colonies.

Science.gov (United States)

Stevanovic, Jevrosima; Stanimirovic, Zoran; Simeunovic, Predrag; Lakic, Nada; Radovic, Ivica; Sokovic, Marina; Griensven, Leo J L D VAN

2018-01-01

This study was done to discover any beneficial effect of a medicinal mushroom Agaricus brasiliensis extract on the honey bee. Firstly, a laboratory experiment was conducted on 640 bees reared in 32 single-use plastic rearing cups. A. brasiliensis extract proved safe in all doses tested (50, 100 and 150 mg/kg/day) irrespective of feeding mode (sugar syrup or candy). Secondly, a three-year field experiment was conducted on 26 colonies treated with a single dose of A. brasiliensis extract (100 mg/kg/day) added to syrup. Each year the colonies were treated once in autumn and twice in spring. The treatments significantly increased colony strength parameters: brood rearing improvement and adult population growth were noticed more often than the increase in honey production and pollen reserves. These positive effects were mainly observed in April. In conclusion, A. brasiliensis extract is safe for the bees and helps maintaining strong colonies, especially in spring.

The effect of Agaricus brasiliensis extract supplementation on honey bee colonies

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JEVROSIMA STEVANOVIC

2018-02-01

Full Text Available ABSTRACT This study was done to discover any beneficial effect of a medicinal mushroom Agaricus brasiliensis extract on the honey bee. Firstly, a laboratory experiment was conducted on 640 bees reared in 32 single-use plastic rearing cups. A. brasiliensis extract proved safe in all doses tested (50, 100 and 150 mg/kg/day irrespective of feeding mode (sugar syrup or candy. Secondly, a three-year field experiment was conducted on 26 colonies treated with a single dose of A. brasiliensis extract (100 mg/kg/day added to syrup. Each year the colonies were treated once in autumn and twice in spring. The treatments significantly increased colony strength parameters: brood rearing improvement and adult population growth were noticed more often than the increase in honey production and pollen reserves. These positive effects were mainly observed in April. In conclusion, A. brasiliensis extract is safe for the bees and helps maintaining strong colonies, especially in spring.

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium

DEFF Research Database (Denmark)

Smith, Ida Mosbech; Baker, A; Arneborg, Nils

2015-01-01

distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase....... In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability......). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. SIGNIFICANCE AND IMPACT...

Nocardia brasiliensis vertebral osteomyelitis and epidural abscess.

Science.gov (United States)

Johnson, Philip; Ammar, Hussam

2013-04-11

Nocardia species exist in the environment as a saprophyte; it is found worldwide in soil and decaying plant matter. They often infect patients with underlying immune compromise, pulmonary disease or history of trauma or surgery. The diagnosis of nocardiosis can be easily missed as it mimics many other granulomatous and neoplastic disease. We report a 69-year-old man who presented with chronic back pain and paraparesis. He was found to have Nocardial brasiliensis vertebral osteomyelitis and epidural abscess. Laminectomy and epidural wash out was performed but with no neurological recovery. This is the second reported case of N brasiliensis vertebral osteomyelitis in the literature.

Drying enhances immunoactivity of spent brewer's yeast cell wall β-D-glucans.

Science.gov (United States)

Liepins, Janis; Kovačova, Elena; Shvirksts, Karlis; Grube, Mara; Rapoport, Alexander; Kogan, Grigorij

2015-07-20

Due to immunological activity, microbial cell wall polysaccharides are defined as 'biological response modifiers' (BRM). Cell walls of spent brewer's yeast also have some BRM activity. However, up to date there is no consensus on the use of spent brewer's yeast D-glucan as specific BRM in humans or animals. The aim of this paper is to demonstrate the potential of spent brewer's yeast β-D-glucans as BRM, and drying as an efficient pretreatment to increase β-D-glucan's immunogenic activity. Our results revealed that drying does not change spent brewer's yeast biomass carbohydrate content as well as the chemical structure of purified β-D-glucan. However, drying increased purified β-D-glucan TNF-α induction activity in the murine macrophage model. We presume drying pretreatment enhances purity of extracted β-D-glucan. This is corroborated with FT-IR analyses of the β-D-glucan spectra. Based on our results, we suggest that dry spent brewer's yeast biomass can be used as a cheap source for high-quality β-D-glucan extraction. Drying in combination with carboxylmethylation (CM), endows spent brewer's yeast β-D-glucan with the immunoactivity similar or exceeding that of a well-characterized fungal BRM pleuran. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of ambient humidity on the strength of the adhesion force of single yeast cell inside environmental-SEM

International Nuclear Information System (INIS)

Shen, Yajing; Nakajima, Masahiro; Ridzuan Ahmad, Mohd; Kojima, Seiji; Homma, Michio; Fukuda, Toshio

2011-01-01

A novel method for measuring an adhesion force of single yeast cell is proposed based on a nanorobotic manipulation system inside an environmental scanning electron microscope (ESEM). The effect of ambient humidity on a single yeast cell adhesion force was studied. Ambient humidity was controlled by adjusting the chamber pressure and temperature inside the ESEM. It has been demonstrated that a thicker water film was formed at a higher humidity condition. The adhesion force between an atomic force microscopy (AFM) cantilever and a tungsten probe which later on known as a substrate was evaluated at various humidity conditions. A micro-puller was fabricated from an AFM cantilever by use of focused ion beam (FIB) etching. The adhesion force of a single yeast cell (W303) to the substrate was measured using the micro-puller at the three humidity conditions: 100%, 70%, and 40%. The results showed that the adhesion force between the single yeast cell and the substrate is much smaller at higher humidity condition. The yeast cells were still alive after being observed and manipulated inside ESEM based on the result obtained from the re-culturing of the single yeast cell. The results from this work would help us to understand the ESEM system better and its potential benefit to the single cell analysis research. -- Research highlights: → A nanorobotic manipulation system was developed inside an ESEM. → A micro-puller was designed for single yeast cell adhesion force measurement. → Yeast cells were still alive after being observed and manipulated inside ESEM. → Yeast cell adhesion force to substrate is smaller at high humidity condition than at low humidity condition.

Effect of ambient humidity on the strength of the adhesion force of single yeast cell inside environmental-SEM

Energy Technology Data Exchange (ETDEWEB)

Shen, Yajing, E-mail: shen@robo.mein.nagoya-u.ac.jp [Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya 464-8603 (Japan); Nakajima, Masahiro [Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya 464-8603 (Japan); Ridzuan Ahmad, Mohd [Department of Mechatronics and Robotics, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Skudai 81310 (Malaysia); Kojima, Seiji; Homma, Michio [Department of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602 (Japan); Fukuda, Toshio [Department of Micro-Nano Systems Engineering, Nagoya University, Nagoya 464-8603 (Japan)

2011-07-15

A novel method for measuring an adhesion force of single yeast cell is proposed based on a nanorobotic manipulation system inside an environmental scanning electron microscope (ESEM). The effect of ambient humidity on a single yeast cell adhesion force was studied. Ambient humidity was controlled by adjusting the chamber pressure and temperature inside the ESEM. It has been demonstrated that a thicker water film was formed at a higher humidity condition. The adhesion force between an atomic force microscopy (AFM) cantilever and a tungsten probe which later on known as a substrate was evaluated at various humidity conditions. A micro-puller was fabricated from an AFM cantilever by use of focused ion beam (FIB) etching. The adhesion force of a single yeast cell (W303) to the substrate was measured using the micro-puller at the three humidity conditions: 100%, 70%, and 40%. The results showed that the adhesion force between the single yeast cell and the substrate is much smaller at higher humidity condition. The yeast cells were still alive after being observed and manipulated inside ESEM based on the result obtained from the re-culturing of the single yeast cell. The results from this work would help us to understand the ESEM system better and its potential benefit to the single cell analysis research. -- Research highlights: {yields} A nanorobotic manipulation system was developed inside an ESEM. {yields} A micro-puller was designed for single yeast cell adhesion force measurement. {yields} Yeast cells were still alive after being observed and manipulated inside ESEM. {yields} Yeast cell adhesion force to substrate is smaller at high humidity condition than at low humidity condition.

Mycetoma caused by Nocardia brasiliensis

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Kar P

1990-01-01

Full Text Available One case of actinomycetoma caused by Nocardia brasiliensis presented with a swelling on the right ankle with multiple sinuses discharging sero-sanguinous material without any granules. He was treated successfully with dapsone followed by surgical excision of the swelling and skin graft.

Actinomycetoma Due To Nocardia Brasiliensis in Tamil Nadu

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V V Pankajalakshmi

1982-01-01

Full Text Available Two cases of actinomycetoma caused by Nocardia Brasiliensis in Tamilians are reported. Both presented with multiple sinuses discharging serosanguinous material without any granules. In the first case, the lesion was located in the thigh and leg and the specific diagnosis was made by histopathology and isolation of N. brasiliensis. In the other, in addition to thigh and leg, the foot was also affected and the causative agent was isolated in pure culture. The geographic distribution of the organism and its incidence and prevalence are discussed.

Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

Science.gov (United States)

Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M; Verstrepen, Kevin J

2015-01-01

Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

Detection and quantitative determination by PIXE of the mutagen Sn2+ in yeast cells

International Nuclear Information System (INIS)

Viau, C.M.; Yoneama, M.-L.; Dias, J.F.; Pungartnik, C.; Brendel, M.; Henriques, J.A.P.

2006-01-01

The main goal of this work was to determine the concentration of Sn 2+ ions in cells of the yeast Saccharomyces cerevisiae and to correlate their quantity with the genotoxicity of intracellularly accumulated metal ions. The intracellular metal content of yeast cells was determined by PIXE (particle-induced X-ray emission) after cell exposure to SnCl 2 . To that end, a thick target protocol was developed for PIXE analysis. The samples were irradiated with a 2 MeV proton beam, while the induced X-rays were detected with a high-purity germanium detector. The results of the toxicity of SnCl 2 and the PIXE analysis performed with two different yeast strains (haploid and diploid) suggest that the exposure of haploid and diploid yeast to Sn 2+ induces DNA lesions and that the absorption depends on the genetic background of each strain

Paracoccidioides brasiliensis, nova amostra isolada de fezes de um pinguim (Pygoscelis adeliae Paracoccidioides brasiliensis, a new strain isolated from a fecal matter of a penguin (Pygoscelis adeliae

Directory of Open Access Journals (Sweden)

Nilma Maciel Garcia

1993-06-01

Full Text Available Os Autores apresentam os resultados obtidos com a amostra "pinguim" de Paracoccidioides, isolada por GEZUELE et al. (1989 na Antártica uruguaia. Das fezes de um desses animais, foi isolado um fungo considerado, recentemente, como nova espécie de Paracoccididoides - P. antarclicus. Os exames micológico e imunoquímico demonstraram tratar-se de Paracoccidioides brasiliensis, inclusive com a verificação da presença da glicoproteína 43 kDa pelos métodos de imunodifusão dupla, SDS-PAGE e imunoeletroforese. A possibilidade de se tratar de uma variedade do Paracoccididoides brasiliensis somente poderá ser confirmada através de outros estudos baseados na chamada taxonomía molecular, incluindo cariotipagem. Os Autores registram o significado epidemiológico deste achado, sugerindo uma revisão nos conhecimentos do nicho ecológico do P. brasiliensis.The Authors show lhe results obtained through the study of a Paracoccidioides strain isolated from a penguin in the Uruguaian An-lartide by GEZUELE et al. (1989. From the fecal matter it was isolated a fungus which was recently considered as a new species of the genus Paracoccidioides - P. antarcticus. However, the mycological and immunochemical studies including the demonstration of the 43 kDa glycoprotein by immunodiffusion test, SDS-PAGE and immunoelectrophoresis disclosed that such strain is similar to P. brasiliensis. Other studies, based on molecular taxonomy, including karyotyping, are the only tools to confirm Lhe possibility of such strain to be a variant of P. brasiliensis. The Authors report the epidemiological significance of that finding and suggest a review in the knowledge of the ecological "niche" of P. brasiliensis.

Mammalia, Rodentia, Sigmodontinae, Holochilus brasiliensis (Desmarest, 1819: Distribution extention

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Formoso, A. E.

2010-01-01

Full Text Available We report the southernmost record for the marsh rats Holochilus brasiliensis 20 km S of Pedro Luro on Hwy3, province of Buenos Aires, Argentina (39°41’31.13”S, 62°40’23.5”W extending the range of the species ca. 110 km S.This represents the first contemporaneous record of H. brasiliensis in Patagonia, and also the only species of sigmodontinerodent with amphibious habits reported in Patagonia.

Kalanchosine dimalate, an anti-inflammatory salt from Kalanchoe brasiliensis.

Science.gov (United States)

Costa, Sônia Soares; de Souza, Maria de Lourdes Mendes; Ibrahim, Tereza; de Melo, Giany Oliveira; de Almeida, Ana Paula; Guette, Catherine; Férézou, Jean-Pierre; Koatz, Vera Lucia G

2006-05-01

This report describes the isolation and characterization of kalanchosine dimalate (KMC), an anti-inflammatory salt from the fresh juice of the aerial parts of Kalanchoe brasiliensis. KMC comprises the new metabolite kalanchosine (1) and malic acid (2) in a 1:2 stoichiometric ratio. Kalanchosine (1), 3,6-diamino-4,5-dihydroxyoctanedioic acid, is the first naturally occurring dimeric bis(gamma-hydroxy-beta-amino acid) and is at least partially responsible for the anti-inflammatory properties of K. brasiliensis.

The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

Energy Technology Data Exchange (ETDEWEB)

Nishimura, Akira; Kawahara, Nobuhiro [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Takagi, Hiroshi, E-mail: hiro@bs.naist.jp [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)

2013-01-04

Highlights: Black-Right-Pointing-Pointer NO is produced from L-arginine in response to elevated temperature in yeast. Black-Right-Pointing-Pointer Tah18 was first identified as the yeast protein involved in NO synthesis. Black-Right-Pointing-Pointer Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe-S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

Engineering tolerance to industrially relevant stress factors in yeast cell factories.

Science.gov (United States)

Deparis, Quinten; Claes, Arne; Foulquié-Moreno, Maria R; Thevelein, Johan M

2017-06-01

The main focus in development of yeast cell factories has generally been on establishing optimal activity of heterologous pathways and further metabolic engineering of the host strain to maximize product yield and titer. Adequate stress tolerance of the host strain has turned out to be another major challenge for obtaining economically viable performance in industrial production. Although general robustness is a universal requirement for industrial microorganisms, production of novel compounds using artificial metabolic pathways presents additional challenges. Many of the bio-based compounds desirable for production by cell factories are highly toxic to the host cells in the titers required for economic viability. Artificial metabolic pathways also turn out to be much more sensitive to stress factors than endogenous pathways, likely because regulation of the latter has been optimized in evolution in myriads of environmental conditions. We discuss different environmental and metabolic stress factors with high relevance for industrial utilization of yeast cell factories and the experimental approaches used to engineer higher stress tolerance. Improving stress tolerance in a predictable manner in yeast cell factories should facilitate their widespread utilization in the bio-based economy and extend the range of products successfully produced in large scale in a sustainable and economically profitable way. © FEMS 2017.

Engineering tolerance to industrially relevant stress factors in yeast cell factories

Science.gov (United States)

Deparis, Quinten; Claes, Arne; Foulquié-Moreno, Maria R.

2017-01-01

Abstract The main focus in development of yeast cell factories has generally been on establishing optimal activity of heterologous pathways and further metabolic engineering of the host strain to maximize product yield and titer. Adequate stress tolerance of the host strain has turned out to be another major challenge for obtaining economically viable performance in industrial production. Although general robustness is a universal requirement for industrial microorganisms, production of novel compounds using artificial metabolic pathways presents additional challenges. Many of the bio-based compounds desirable for production by cell factories are highly toxic to the host cells in the titers required for economic viability. Artificial metabolic pathways also turn out to be much more sensitive to stress factors than endogenous pathways, likely because regulation of the latter has been optimized in evolution in myriads of environmental conditions. We discuss different environmental and metabolic stress factors with high relevance for industrial utilization of yeast cell factories and the experimental approaches used to engineer higher stress tolerance. Improving stress tolerance in a predictable manner in yeast cell factories should facilitate their widespread utilization in the bio-based economy and extend the range of products successfully produced in large scale in a sustainable and economically profitable way. PMID:28586408

Intestinal mucosal mast cells from rats infected with Nippostrongylus brasiliensis contain protease-resistant chondroitin sulfate di-B proteoglycans

International Nuclear Information System (INIS)

Stevens, R.L.; Lee, T.D.G.; Seldin, D.C.; Austen, K.F.; Befus, A.D.; Bienenstock, J.

1986-01-01

Rats infected with the helminth Nippostrongylus brasiliensis were injected i.p. with 2 mCi of [ 35 S] sulfate on days 13, 15, 17, and 19 after infection. The intestines were removed from animals on day 20 or 21 after infection, the intestinal cells were obtained by collagenase treatment and mechanical dispersion of the tissue, and the 35 S-labeled mucosal mast cells (MMC) were enriched to 60 to 65% purity by Percoll centrifugation. The isolated proteoglycans were of approx. 150,000 m.w., were resistant to pronase degradation, and contained highly sulfated chondroitin sulfate side chains. The presence in normal mammalian cells of chondroitin sulfate proteoglycans that contain a high percentage of the unusual disulfated di-B disaccharide has not been previously reported. The rat intestinal MMC proteoglycans are the first chondroitin sulfate proteoglycans that have been isolated from an enriched populations of normal mast cells. They are homologous to the chondroitin sulfate-rich proteoglycans of the transformed rat basophilic leumekia-1 cell and the cultured interleukin 3-dependent mouse bone marrow-derived mast cell, in that these chondroitin sulfate proteoglycans are all highly sulfated, protease-resistant proteoglycans

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

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Vágvölgyi Csaba

2010-02-01

Full Text Available Abstract 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.

Evidence that pulsed electric field treatment enhances the cell wall porosity of yeast cells.

Science.gov (United States)

Ganeva, Valentina; Galutzov, Bojidar; Teissie, Justin

2014-02-01

The application of rectangular electric pulses, with 0.1-2 ms duration and field intensity of 2.5-4.5 kV/cm, to yeast suspension mediates liberation of cytoplasmic proteins without cell lysis. The aim of this study was to evaluate the effect of pulsed electric field with similar parameters on cell wall porosity of different yeast species. We found that electrically treated cells become more susceptible to lyticase digestion. In dependence on the strain and the electrical conditions, cell lysis was obtained at 2-8 times lower enzyme concentration in comparison with control untreated cells. The increase of the maximal lysis rate was between two and nine times. Furthermore, when applied at low concentration (1 U/ml), the lyticase enhanced the rate of protein liberation from electropermeabilized cells without provoking cell lysis. Significant differences in the cell surface of control and electrically treated cells were revealed by scanning electron microscopy. Data presented in this study allow us to conclude that electric field pulses provoke not only plasma membrane permeabilization, but also changes in the cell wall structure, leading to increased wall porosity.

Cytokine production and lymphocyte proliferation in patients with Nocardia brasiliensis actinomycetoma.

Science.gov (United States)

Méndez-Tovar, Luis J; Mondragón-González, Rafael; Vega-López, Francisco; Dockrell, Hazel M; Hay, Roderick; López-Martínez, Rubén; Manzano-Gayosso, Patricia; Hernández-Hernández, Francisca; Padilla-Desgarennes, Carmen; Bonifaz, Alexandro

2004-11-01

IFN-gamma, TNF-alpha, IL-4, IL-10 and IL-12 concentrations in the supernatant of peripheral blood mononuclear cell (PBMC) cultures and the in vitro proliferation of PBMC were studied in 25 patients with actinomycetoma caused by Nocardia brasiliensis and in 10 healthy controls from endemic zones. Cell cultures were stimulated by a N. brasiliensis crude cytoplasmic antigen (NB) and five semi-purified protein fractions (NB2, NB4, NB6, NB8, and NB10) separated by isoelectric. Phytohemagglutinin (PHA) and purified protein derivative (PPD) of Mycobacterium tuberculosis were used as control antigens. Skin tests were performed by injecting 0.1 ml of candidin and PPD intradermally (ID). Patients showed a poor response to tuberculin, while their response to candidin was more than two fold greater than that observed in the controls. Cell proliferation showed no statistically significant differences in either group. IFN-gamma production was higher in the healthy controls than in the patients, whereas TNF-alpha secretion was slightly higher in the patients' cultures. IL-4 was detected in the patients' cultures but not in the controls. IL-10 and IL-12 were present at low concentrations in both groups. These results suggest that patients with actinomycetoma show normal antigen recognition, but with low IFN-gamma production, and higher concentrations of IL-4, IL-10 and TNF-alpha in the patients' PBMC cultures, indicating that they probably have a Th2 type of immune response.

The CWI Pathway: Regulation of the Transcriptional Adaptive Response to Cell Wall Stress in Yeast

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Ana Belén Sanz

2017-12-01

Full Text Available Fungi are surrounded by an essential structure, the cell wall, which not only confers cell shape but also protects cells from environmental stress. As a consequence, yeast cells growing under cell wall damage conditions elicit rescue mechanisms to provide maintenance of cellular integrity and fungal survival. Through transcriptional reprogramming, yeast modulate the expression of genes important for cell wall biogenesis and remodeling, metabolism and energy generation, morphogenesis, signal transduction and stress. The yeast cell wall integrity (CWI pathway, which is very well conserved in other fungi, is the key pathway for the regulation of this adaptive response. In this review, we summarize the current knowledge of the yeast transcriptional program elicited to counterbalance cell wall stress situations, the role of the CWI pathway in the regulation of this program and the importance of the transcriptional input received by other pathways. Modulation of this adaptive response through the CWI pathway by positive and negative transcriptional feedbacks is also discussed. Since all these regulatory mechanisms are well conserved in pathogenic fungi, improving our knowledge about them will have an impact in the developing of new antifungal therapies.

In Vitro Activities of New Antimicrobials against Nocardia brasiliensis

Science.gov (United States)

Vera-Cabrera, Lucio; Gonzalez, Eva; Choi, Sung H.; Welsh, Oliverio

2004-01-01

The in vitro sensitivities of 30 strains of Nocardia brasiliensis to DA-7867, gatifloxacin, moxifloxacin, and BMS-284756 (garenoxacin) were determined using the broth microdilution method. All N. brasiliensis strains were sensitive to these antimicrobials. The most active drug in vitro was DA-7867, with a MIC at which 90% of the isolates tested were inhibited of 0.03 μg/ml and a MIC at which 50% of the isolates tested were inhibited of 0.06 μg/ml. PMID:14742215

Obtaining sorbents of metal ions based on yeast cells Rhodotorula glutinis

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Zh. Tattibayeva

2013-05-01

Full Text Available Ability to separate Cu2+ and Pb2+ ions from solution using yeast cells Rhodotorulа glutinis were considered. The degree of water purification in this case is of 60-70%. To increase the degree of binding of metal ions with cells and facilitate separation processes of water sorbents their immobilization on the surface of the water in the presence of polyethyleneimine was carried out. It is shown that under optimal conditions on the surface of 1 g diatomite 18 ∙ 106 cells is adsorbed. The high sorption capacity of diatomite justified its porosity. IR spectroscopic study of the interaction of the ions Cu2+ and Pb2+ with cell surface showed that high affinity Pb2 + ions to the surface of yeast cells is connected with form of slightly soluble compounds with the phosphate ions.

Types of cell death and methods of their detection in yeast Saccharomyces cerevisiae

NARCIS (Netherlands)

Wloch-Salamon, D.M.; Bem, A.E.

2013-01-01

The occurrence of programmed cell death in unicellular organisms is a subject that arouses great interest of theoreticians and experimental scientists. Already found evolutionarily conserved genes and metabolic pathways confirmed its existence in yeast, protozoa and even bacteria. In the yeast

Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

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Elham Aslankoohi

Full Text Available Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

A novel yeast cell-based screen identifies flavone as a tankyrase inhibitor

International Nuclear Information System (INIS)

Yashiroda, Yoko; Okamoto, Reika; Hatsugai, Kaori; Takemoto, Yasushi; Goshima, Naoki; Saito, Tamio; Hamamoto, Makiko; Sugimoto, Yoshikazu; Osada, Hiroyuki; Seimiya, Hiroyuki; Yoshida, Minoru

2010-01-01

The telomere-associated protein tankyrase 1 is a poly(ADP-ribose) polymerase and is considered to be a promising target for cancer therapy, especially for BRCA-associated cancers. However, an efficient assay system for inhibitor screening has not been established, mainly due to the difficulty of efficient preparation of the enzyme and its substrate. Here, we report a cell-based assay system for detecting inhibitory activity against tankyrase 1. We found that overexpression of the human tankyrase 1 gene causes a growth defect in the fission yeast Schizosaccharomyces pombe. Chemicals that restore the growth defect phenotype can be identified as potential tankyrase 1 inhibitors. We performed a high-throughput screen using this system, and identified flavone as a compound that restores the growth of yeast cells overexpressing tankyrase 1. Indeed, flavone inhibited poly(ADP-ribosyl)ation of proteins caused by overexpression of tankyrase 1 in yeast cells. This system allows rapid identification of inhibitory activity against tankyrase 1 and is amenable to high-throughput screening using robotics.

Effect of selenium on the Hg, Zn, Fe and Co content of yeast cells

International Nuclear Information System (INIS)

Czauderna, M.; Peplowski, A.; Smolinski, S.

1992-01-01

The yeast cells, Saccharomyces cerevisiae, were exposed to Hg 2+ ions (10 -4 M) and SeO 2 (2x10 -4 -10 -2 M) or Se-methionine (2x10 -4 M). Instrumental neutron activation analysis (INAA) was used to analyze changes in the Hg, Zn,Fe and Co levels in these cells. When the yeast was incubated in a medium containing 10 -3 M and 10 -2 M Se) 2 , the Hg content of the yeast markedly increased. It was also found that the uptake of Se and Hg influenced the levels of Zn, Fe and Co found in the cells. While the presence of Se-methionine (Se-Met), SeO 2 or Hg 2+ ions caused increases in the intracellular Zn levels, the combined presence of Hg 2+ and SeO 2 and their assumed interaction, reduced the efficiency of Se for increasing the Zn content of yeast. (author) 17 refs.; 3 tabs

In Vivo and In Vitro Toxicity Evaluation of Hydroethanolic Extract of Kalanchoe brasiliensis (Crassulaceae) Leaves.

Science.gov (United States)

Fonseca, Aldilane Gonçalves; Ribeiro Dantas, Luzia Leiros Sena Fernandes; Fernandes, Júlia Morais; Zucolotto, Silvana Maria; Lima, Adley Antoninni Neves; Soares, Luiz Alberto Lira; Rocha, Hugo Alexandre Oliveira; Lemos, Telma Maria Araújo Moura

2018-01-01

The species Kalanchoe brasiliensis , known as "Saião , " has anti-inflammatory, antimicrobial, and antihistamine activities. It also has the quercetin and kaempferol flavonoids, which exert their therapeutic activities. With extensive popular use besides the defined therapeutical properties, the study of possible side effects is indispensable. The objective of this study is to evaluate the toxicity in vitro and in vivo from the hydroethanolic extract of the leaves of K. brasiliensis . The action of the extract (concentrations from 0.1 to 1000 uL/100 uL) in normal and tumor cells was evaluated using the MTT method. Acute toxicity and subchronic toxicity were evaluated in mice with doses of 250 to 1000 mg/kg orally, following recognized protocols. The in vitro results indicated cytotoxic activity for 3T3 cell line (normal) and 786-0 (kidney carcinoma), showing the activity to be concentration-dependent, reaching 92.23% cell inhibition. In vivo , the extract showed no significant toxicity; only liver changes related to acute toxicity and some signs of liver damage, combining biochemical and histological data. In general, the extract showed low or no toxicity, introducing itself as safe for use with promising therapeutic potential.

Yeast Extract Promotes Cell Growth and Induces Production of Polyvinyl Alcohol-Degrading Enzymes

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Min Li

2011-01-01

Full Text Available Polyvinyl alcohol-degrading enzymes (PVAases have a great potential in bio-desizing processes for its low environmental impact and low energy consumption. In this study, the effect of yeast extract on PVAases production was investigated. A strategy of four-point yeast extract addition was developed and applied to maximize cell growth and PVAases production. As a result, the maximum dry cell weight achieved was 1.48 g/L and the corresponding PVAases activity was 2.99 U/mL, which are 46.5% and 176.8% higher than the control, respectively. Applying this strategy in a 7 L fermentor increased PVAases activity to 3.41 U/mL. Three amino acids (glycine, serine, and tyrosine in yeast extract play a central role in the production of PVAases. These results suggest that the new strategy of four-point yeast extract addition could benefit PVAases production.

A Stochastic Model of the Yeast Cell Cycle Reveals Roles for Feedback Regulation in Limiting Cellular Variability.

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Barik, Debashis; Ball, David A; Peccoud, Jean; Tyson, John J

2016-12-01

The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs) and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system. In this paper we provide a stochastic model of the budding yeast cell cycle that accurately accounts for the variable phenotypes of wild-type cells and more than 20 mutant yeast strains simulated in different growth conditions. We specifically tested the role of feedback regulations mediated by G1- and SG2M-phase cyclins to minimize the noise in cell cycle progression. Details of the model are informed and tested by quantitative measurements (by fluorescence in situ hybridization) of the joint distributions of mRNA populations in yeast cells. We use the model to predict the phenotypes of ~30 mutant yeast strains that have not yet been characterized experimentally.

A Stochastic Model of the Yeast Cell Cycle Reveals Roles for Feedback Regulation in Limiting Cellular Variability.

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Debashis Barik

2016-12-01

Full Text Available The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system. In this paper we provide a stochastic model of the budding yeast cell cycle that accurately accounts for the variable phenotypes of wild-type cells and more than 20 mutant yeast strains simulated in different growth conditions. We specifically tested the role of feedback regulations mediated by G1- and SG2M-phase cyclins to minimize the noise in cell cycle progression. Details of the model are informed and tested by quantitative measurements (by fluorescence in situ hybridization of the joint distributions of mRNA populations in yeast cells. We use the model to predict the phenotypes of ~30 mutant yeast strains that have not yet been characterized experimentally.

Morphological Studies on the Triatoma brasiliensis Neiva, 1911 (Hemiptera, Reduviidae, Triatominae Genital Structures and Eggs of Different Chromatic Forms

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Jane Costa

1997-07-01

Full Text Available Triatoma brasiliensis is considered one of the most important Chagas disease vectors being a widespread species in semiarid areas of northeastern Brazil. The species displays distinct chromatic patterns of the cuticle in different localities. Four populations were analyzed in this study: 1-Caicó, Rio Grande do Norte, it will be called the brasiliensis population; 2-Espinosa, Minas Gerais, the melanica population; 3-Petrolina, Pernambuco, the macromelasoma population, and 4-Juazeiro, Bahia, the darker one in overall cuticle coloration, the Juazeiro population. In order to differentiate the four populations of T. brasiliensis, a comparative morphological analysis of external genital structures and of eggs were carried out. The analysis of the male genital structures evidenced minor individual structural variations that did not correlate with chromatic differences or the geographical origins, emphasizing the importance of examining sufficiently large and representative samples before using minor genital variations for taxonomic diagnosis. By scanning electron microscopy of the egg exochorion, each chromatic population presented a distinct ornamentation pattern. The melanica population differed mainly from the other populations studied since it had about 40.6%, 69.6% and 76.6% more perforations, on each cell exochorion, than the brasiliensis, the Juazeiro and the macromelasoma populations respectively. In the melanica population the perforation layout is also peculiar, with densely distributed perforations over all the egg surface. Morphometric measures of the eggs showed statistically significant differences: the macromelasoma population presented the longest length (2.43 mm while the shortest was recorded in the brasiliensis population (2.29 mm.

Identification of thermostable β-xylosidase activities produced by Aspergillus brasiliensis and Aspergillus niger

DEFF Research Database (Denmark)

Pedersen, Mads; Lauritzen, Henrik Klitgaard; Frisvad, Jens Christian

2007-01-01

Twenty Aspergillus strains were evaluated for production of extracellular cellulolytic and xylanolytic activities. Aspergillus brasiliensis, A. niger and A. japonicus produced the highest xylanase activities with the A. brasiliensis and A. niger strains producing thermostable beta......-xylosidases. The beta-xylosidase activities of the A. brasiliensis and A. niger strains had similar temperature and pH optima at 75 degrees C and pH 5 and retained 62% and 99%, respectively, of these activities over 1 h at 60 degrees C. At 75 degrees C, these values were 38 and 44%, respectively. Whereas A. niger...

Cutaneous Type of Nocardiosis Caused by Nocardia brasiliensis in an Elderly Patient

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Chen-Yi Su

2012-06-01

Full Text Available Acute soft tissue infection with Nocardia brasiliensis is an uncommon manifestation in the elderly. A case of cellulitis and an abscess on the foot due to N. brasiliensis in a 77-year-old man with chronic obstructive pulmonary disease is reported. N. brasiliensis was isolated from fluid from the bulla. Treatment with trimethoprim–sulfamethoxazole for 6 months led to complete resolution and no evidence of recurrence was noted. Nocardia infection must be considered in the differential diagnosis for elderly patients with soft tissue infection, especially in those with severe underlying diseases, and we suggest that trimethoprim–sulfamethoxazole is an effective and safe treatment.

Screening of intact yeasts and cell extracts to reduce Scrapie prions during biotransformation of food waste.

Science.gov (United States)

Huyben, David; Boqvist, Sofia; Passoth, Volkmar; Renström, Lena; Allard Bengtsson, Ulrika; Andréoletti, Olivier; Kiessling, Anders; Lundh, Torbjörn; Vågsholm, Ivar

2018-02-08

Yeasts can be used to convert organic food wastes to protein-rich animal feed in order to recapture nutrients. However, the reuse of animal-derived waste poses a risk for the transmission of infectious prions that can cause neurodegeneration and fatality in humans and animals. The aim of this study was to investigate the ability of yeasts to reduce prion activity during the biotransformation of waste substrates-thereby becoming a biosafety hurdle in such a circular food system. During pre-screening, 30 yeast isolates were spiked with Classical Scrapie prions and incubated for 72 h in casein substrate, as a waste substitute. Based on reduced Scrapie seeding activity, waste biotransformation and protease activities, intact cells and cell extracts of 10 yeasts were further tested. Prion analysis showed that five yeast species reduced Scrapie seeding activity by approximately 1 log10 or 90%. Cryptococcus laurentii showed the most potential to reduce prion activity since both intact and extracted cells reduced Scrapie by 1 log10 and achieved the highest protease activity. These results show that select forms of yeast can act as a prion hurdle during the biotransformation of waste. However, the limited ability of yeasts to reduce prion activity warrants caution as a sole barrier to transmission as higher log reductions are needed before using waste-cultured yeast in circular food systems.

Prions in yeast

OpenAIRE

Bezdíčka, Martin

2013-01-01

The thesis describes yeast prions and their biological effects on yeast in general. It defines the basic characteristics of yeast prions, that distinguish prions from other proteins. The thesis introduces various possibilities of prion formation, and propagation as well as specific types of yeast prions, including various functions of most studied types of prions. The thesis also focuses on chaperones that affect the state of yeast prions in cells. Lastly, the thesis indicates similarities be...

A set of nutrient limitations trigger yeast cell death in a nitrogen-dependent manner during wine alcoholic fermentation.

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Camille Duc

Full Text Available Yeast cell death can occur during wine alcoholic fermentation. It is generally considered to result from ethanol stress that impacts membrane integrity. This cell death mainly occurs when grape musts processing reduces lipid availability, resulting in weaker membrane resistance to ethanol. However the mechanisms underlying cell death in these conditions remain unclear. We examined cell death occurrence considering yeast cells ability to elicit an appropriate response to a given nutrient limitation and thus survive starvation. We show here that a set of micronutrients (oleic acid, ergosterol, pantothenic acid and nicotinic acid in low, growth-restricting concentrations trigger cell death in alcoholic fermentation when nitrogen level is high. We provide evidence that nitrogen signaling is involved in cell death and that either SCH9 deletion or Tor inhibition prevent cell death in several types of micronutrient limitation. Under such limitations, yeast cells fail to acquire any stress resistance and are unable to store glycogen. Unexpectedly, transcriptome analyses did not reveal any major changes in stress genes expression, suggesting that post-transcriptional events critical for stress response were not triggered by micronutrient starvation. Our data point to the fact that yeast cell death results from yeast inability to trigger an appropriate stress response under some conditions of nutrient limitations most likely not encountered by yeast in the wild. Our conclusions provide a novel frame for considering both cell death and the management of nutrients during alcoholic fermentation.

Effects of metal salt catalysts on yeast cell growth in ethanol conversion

Science.gov (United States)

Chung-Yun Hse; Yin Lin

2009-01-01

The effects of the addition of metal salts and metal salt-catalyzed hydrolyzates on yeast cell growth in ethanol fermentation were investigated. Four yeast strains (Saccharomyces cerevisiae WT1, Saccharomyces cerevisiae MT81, Candida sp. 1779, and Klumaromyces fragilis), four metal salts (CuCl2, FeCl3, AgNO3, and I2), two metal salt-catalyzed hydrolyzates (...

Involvement of flocculin in negative potential-applied ITO electrode adhesion of yeast cells

Science.gov (United States)

Koyama, Sumihiro; Tsubouchi, Taishi; Usui, Keiko; Uematsu, Katsuyuki; Tame, Akihiro; Nogi, Yuichi; Ohta, Yukari; Hatada, Yuji; Kato, Chiaki; Miwa, Tetsuya; Toyofuku, Takashi; Nagahama, Takehiko; Konishi, Masaaki; Nagano, Yuriko; Abe, Fumiyoshi

2015-01-01

The purpose of this study was to develop novel methods for attachment and cultivation of specifically positioned single yeast cells on a microelectrode surface with the application of a weak electrical potential. Saccharomyces cerevisiae diploid strains attached to an indium tin oxide/glass (ITO) electrode to which a negative potential between −0.2 and −0.4 V vs. Ag/AgCl was applied, while they did not adhere to a gallium-doped zinc oxide/glass electrode surface. The yeast cells attached to the negative potential-applied ITO electrodes showed normal cell proliferation. We found that the flocculin FLO10 gene-disrupted diploid BY4743 mutant strain (flo10Δ /flo10Δ) almost completely lost the ability to adhere to the negative potential-applied ITO electrode. Our results indicate that the mechanisms of diploid BY4743 S. cerevisiae adhesion involve interaction between the negative potential-applied ITO electrode and the Flo10 protein on the cell wall surface. A combination of micropatterning techniques of living single yeast cell on the ITO electrode and omics technologies holds potential of novel, highly parallelized, microchip-based single-cell analysis that will contribute to new screening concepts and applications. PMID:26187908

From mannan to bioethanol: cell surface co-display of β-mannanase and β-mannosidase on yeast Saccharomyces cerevisiae.

Science.gov (United States)

Ishii, Jun; Okazaki, Fumiyoshi; Djohan, Apridah Cameliawati; Hara, Kiyotaka Y; Asai-Nakashima, Nanami; Teramura, Hiroshi; Andriani, Ade; Tominaga, Masahiro; Wakai, Satoshi; Kahar, Prihardi; Yopi; Prasetya, Bambang; Ogino, Chiaki; Kondo, Akihiko

2016-01-01

Mannans represent the largest hemicellulosic fraction in softwoods and also serve as carbohydrate stores in various plants. However, the utilization of mannans as sustainable resources has been less advanced in sustainable biofuel development. Based on a yeast cell surface-display technology that enables the immobilization of multiple enzymes on the yeast cell walls, we constructed a recombinant Saccharomyces cerevisiae strain that co-displays β-mannanase and β-mannosidase; this strain is expected to facilitate ethanol fermentation using mannan as a biomass source. Parental yeast S. cerevisiae assimilated mannose and glucose as monomeric sugars, producing ethanol from mannose. We constructed yeast strains that express tethered β-mannanase and β-mannosidase; co-display of the two enzymes on the cell surface was confirmed by immunofluorescence staining and enzyme activity assays. The constructed yeast cells successfully hydrolyzed 1,4-β-d-mannan and produced ethanol by assimilating the resulting mannose without external addition of enzymes. Furthermore, the constructed strain produced ethanol from 1,4-β-d-mannan continually during the third batch of repeated fermentation. Additionally, the constructed strain produced ethanol from ivory nut mannan; ethanol yield was improved by NaOH pretreatment of the substrate. We successfully displayed β-mannanase and β-mannosidase on the yeast cell surface. Our results clearly demonstrate the utility of the strain co-displaying β-mannanase and β-mannosidase for ethanol fermentation from mannan biomass. Thus, co-tethering β-mannanase and β-mannosidase on the yeast cell surface provides a powerful platform technology for yeast fermentation toward the production of bioethanol and other biochemicals from lignocellulosic materials containing mannan components.

Yeast surface displaying glucose oxidase as whole-cell biocatalyst: construction, characterization, and its electrochemical glucose sensing application.

Science.gov (United States)

Wang, Hongwei; Lang, Qiaolin; Li, Liang; Liang, Bo; Tang, Xiangjiang; Kong, Lingrang; Mascini, Marco; Liu, Aihua

2013-06-18

The display of glucose oxidase (GOx) on yeast cell surface using a-agglutinin as an anchor motif was successfully developed. Both the immunochemical analysis and enzymatic assay showed that active GOx was efficiently expressed and translocated on the cell surface. Compared with conventional GOx, the yeast cell surface that displayed GOx (GOx-yeast) demonstrated excellent enzyme properties, such as good stability within a wide pH range (pH 3.5-11.5), good thermostability (retaining over 94.8% enzyme activity at 52 °C and 84.2% enzyme activity at 56 °C), and high d-glucose specificity. In addition, direct electrochemistry was achieved at a GOx-yeast/multiwalled-carbon-nanotube modified electrode, suggesting that the host cell of yeast did not have any adverse effect on the electrocatalytic property of the recombinant GOx. Thus, a novel electrochemical glucose biosensor based on this GOx-yeast was developed. The as-prepared biosensor was linear with the concentration of d-glucose within the range of 0.1-14 mM and a low detection limit of 0.05 mM (signal-to-noise ratio of S/N = 3). Moreover, the as-prepared biosensor is stable, specific, reproducible, simple, and cost-effective, which can be applicable for real sample detection. The proposed strategy to construct robust GOx-yeast may be applied to explore other oxidase-displaying-system-based whole-cell biocatalysts, which can find broad potential application in biosensors, bioenergy, and industrial catalysis.

Blood parameter analysis and morphological alterations as biomarkers on the health of Hoplias malabaricus and Geophagus brasiliensis

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Silvia Romão

2006-05-01

Full Text Available This study aimed to assess the influence of the environment on fish health. Samples of Hoplias malabaricus and Geophagus brasiliensis, were collected from three different environments: area I was urban and areas II and III were rural. Analyses of red blood cell count, microhematocrit, hemoglobin concentration, white blood cell count and differential white cell count in blood smear were carried out. Mean corpuscular volume and mean corpuscular hemoglobin concentration were calculated. To analyze morphological alterations, gills, liver, kidney and gonads were submitted to routine histological processing. Individuals collected from area III had slightly lower blood indices than collected from area I . Severe kidney changes, degeneration of and crystallization within kidney tubules were observed. In area I, crystallization was observed in 92% of the specimens of G. brasiliensis. These results suggested that such alterations were related with poor water circulation in the place.Este trabalho teve como objetivo avaliar a influência do ambiente sobre a higidez dos peixes. Animais, das espécies Hoplias malabaricus e Geophagus brasiliensis foram coletados em três ambientes distintos, sendo ambiente I região urbana e ambientes II e III em região rural. Foram realizadas análises do número total de eritrócitos por microlitro de sangue, microhematócrito, taxa de hemoglobina, porcentagem de leucócito e contagem diferencial de leucócitos em extensão sanguínea. Calcularam-se os índices hematimétricos absolutos: volume corpuscular médio e concentração de hemoglobina corpuscular média. Para análises das alterações morfológicas, brânquias, fígado, gônadas e rim seguiram processamento histológico de rotina. Foram observados índices hematológicos ligeiramente menores em indivíduos coletados no ambiente III em relação aos animais coletados no ambiente I. As análises histológicas de brânquias, fígado e gônadas das espécies G

Nanoscopic morphological changes in yeast cell surfaces caused by oxidative stress: an atomic force microscopic study.

Science.gov (United States)

Canetta, Elisabetta; Walker, Graeme M; Adya, Ashok K

2009-06-01

Nanoscopic changes in the cell surface morphology of the yeasts Saccharomyces cerevisiae (strain NCYC 1681) and Schizosaccharomyces pombe (strain DVPB 1354), due to their exposure to varying concentrations of hydrogen peroxide (oxidative stress), were investigated using an atomic force microscope (AFM). Increasing hydrogen peroxide concentration led to a decrease in cell viabilities and mean cell volumes, and an increase in the surface roughness of the yeasts. In addition, AFM studies revealed that oxidative stress caused cell compression in both S. cerevisiae and Schiz. pombe cells and an increase in the number of aged yeasts. These results confirmed the importance and usefulness of AFM in investigating the morphology of stressed microbial cells at the nanoscale. The results also provided novel information on the relative oxidative stress tolerance of S. cerevisiae and Schiz. pombe.

Non-Coding RNAs are Differentially Expressed by Nocardia brasiliensis in Vitro and in Experimental Actinomycetoma.

Science.gov (United States)

Cruz-Rabadán, Josué S; Miranda-Ríos, Juan; Espín-Ocampo, Guadalupe; Méndez-Tovar, Luis J; Maya-Pineda, Héctor Rubén; Hernández-Hernández, Francisca

2017-01-01

Nocardia spp. are common soil-inhabiting bacteria that frequently infect humans through traumatic injuries or inhalation routes and cause infections, such as actinomycetoma and nocardiosis, respectively. Nocardia brasiliensis is the main aetiological agent of actinomycetoma in various countries. Many bacterial non-coding RNAs are regulators of genes associated with virulence factors. The aim of this work was to identify non-coding RNAs (ncRNAs) expressed during infection conditions and in free-living form ( in vitro ) in Nocardia brasiliensis . The N. brasiliensis transcriptome (predominately brasiliensis infection compared with the in vitro conditions. The results of this work suggest a possible role for these transcripts in the regulation of virulence genes in actinomycetoma pathogenesis.

Synthesis of polypyrrole within the cell wall of yeast by redox-cycling of [Fe(CN)6](3-)/[Fe(CN)6](4-).

Science.gov (United States)

Ramanavicius, Arunas; Andriukonis, Eivydas; Stirke, Arunas; Mikoliunaite, Lina; Balevicius, Zigmas; Ramanaviciene, Almira

2016-02-01

Yeast cells are often used as a model system in various experiments. Moreover, due to their high metabolic activity, yeast cells have a potential to be applied as elements in the design of biofuel cells and biosensors. However a wider application of yeast cells in electrochemical systems is limited due to high electric resistance of their cell wall. In order to reduce this problem we have polymerized conducting polymer polypyrrole (Ppy) directly in the cell wall and/or within periplasmic membrane. In this research the formation of Ppy was induced by [Fe(CN)6](3-)ions, which were generated from K4[Fe(CN)6], which was initially added to polymerization solution. The redox process was catalyzed by oxido-reductases, which are present in the plasma membrane of yeast cells. The formation of Ppy was confirmed by spectrophotometry and atomic force microscopy. It was confirmed that the conducting polymer polypyrrole was formed within periplasmic space and/or within the cell wall of yeast cells, which were incubated in solution containing pyrrole, glucose and [Fe(CN)6](4-). After 24h drying at room temperature we have observed that Ppy-modified yeast cell walls retained their initial spherical form. In contrast to Ppy-modified cells, the walls of unmodified yeast have wrinkled after 24h drying. The viability of yeast cells in the presence of different pyrrole concentrations has been evaluated. Copyright © 2015 Elsevier Inc. All rights reserved.

Study of budding yeast colony formation and its characterizations by using circular granular cell

Science.gov (United States)

Aprianti, D.; Haryanto, F.; Purqon, A.; Khotimah, S. N.; Viridi, S.

2016-03-01

Budding yeast can exhibit colony formation in solid substrate. The colony of pathogenic budding yeast can colonize various surfaces of the human body and medical devices. Furthermore, it can form biofilm that resists drug effective therapy. The formation of the colony is affected by the interaction between cells and with its growth media. The cell budding pattern holds an important role in colony expansion. To study this colony growth, the molecular dynamic method was chosen to simulate the interaction between budding yeast cells. Every cell was modelled by circular granular cells, which can grow and produce buds. Cohesion force, contact force, and Stokes force govern this model to mimic the interaction between cells and with the growth substrate. Characterization was determined by the maximum (L max) and minimum (L min) distances between two cells within the colony and whether two lines that connect the two cells in the maximum and minimum distances intersect each other. Therefore, it can be recognized the colony shape in circular, oval, and irregular shapes. Simulation resulted that colony formation are mostly in oval shape with little branch. It also shows that greater cohesion strength obtains more compact colony formation.

S-Adenosyl-L-methionine protects the probiotic yeast, Saccharomyces boulardii, from acid-induced cell death.

Science.gov (United States)

Cascio, Vincent; Gittings, Daniel; Merloni, Kristen; Hurton, Matthew; Laprade, David; Austriaco, Nicanor

2013-02-13

Saccharomyces boulardii is a probiotic yeast routinely used to prevent and to treat gastrointestinal disorders, including the antibiotic-associated diarrhea caused by Clostridium difficile infections. However, only 1-3% of the yeast administered orally is recovered alive in the feces suggesting that this yeast is unable to survive the acidic environment of the gastrointestinal tract. We provide evidence that suggests that S. boulardii undergoes programmed cell death (PCD) in acidic environments, which is accompanied by the generation of reactive oxygen species and the appearance of caspase-like activity. To better understand the mechanism of cell death at the molecular level, we generated microarray gene expression profiles of S. boulardii cells cultured in an acidic environment. Significantly, functional annotation revealed that the up-regulated genes were significantly over-represented in cell death pathways Finally, we show that S-adenosyl-L-methionine (AdoMet), a commercially available, FDA-approved dietary supplement, enhances the viability of S. boulardii in acidic environments, most likely by preventing programmed cell death. In toto, given the observation that many of the proven health benefits of S. boulardii are dependent on cell viability, our data suggests that taking S. boulardii and AdoMet together may be a more effective treatment for gastrointestinal disorders than taking the probiotic yeast alone.

Synchronization of glycolytic oscillations in a yeast cell population

DEFF Research Database (Denmark)

Dano, S.; Hynne, F.; De Monte, Silvia

2001-01-01

The mechanism of active phase synchronization in a suspension of oscillatory yeast cells has remained a puzzle for almost half a century. The difficulty of the problem stems from the fact that the synchronization phenomenon involves the entire metabolic network of glycolysis and fermentation, and...

Brasilien Vervain (Verbena brasiliensis Vell. in Colkheti flora

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I. Sh. Mikeladze

2017-06-01

In this work the current condition, invasive indicators, bio morphological characteristics and growth-development properties of new invasive species, South American origin Verbena Brasiliensis spread in Colkheti flora (Western Georgia's seaside part is given. In Colkheti it is mainly spread in the seaside, along the roads, along the railroad, on the ruderal places, near channels and rivers, deserted building sites, landfills, non-agricultural lands. Verbena Brasiliensis is a perennial, erect, branched, 50–210 cm height. The plant starts flowering in April–May and lasts till November. It is distinguished with high reproductivity. Fully grown plant in the second year develops about 90000–100000 seeds. Consequently the area of plant spread is gradually growing.

Mitochondrion-mediated cell death: dissecting yeast apoptosis for a better understanding of neurodegeneration

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Braun, Ralf J., E-mail: ralf.braun@uni-bayreuth.de [Institut für Zellbiologie, Universität Bayreuth, Bayreuth (Germany)

2012-11-28

Mitochondrial damage and dysfunction are common hallmarks for neurodegenerative disorders, including Alzheimer, Parkinson, Huntington diseases, and the motor neuron disorder amyotrophic lateral sclerosis. Damaged mitochondria pivotally contribute to neurotoxicity and neuronal cell death in these disorders, e.g., due to their inability to provide the high energy requirements for neurons, their generation of reactive oxygen species (ROS), and their induction of mitochondrion-mediated cell death pathways. Therefore, in-depth analyses of the underlying molecular pathways, including cellular mechanisms controlling the maintenance of mitochondrial function, is a prerequisite for a better understanding of neurodegenerative disorders. The yeast Saccharomyces cerevisiae is an established model for deciphering mitochondrial quality control mechanisms and the distinct mitochondrial roles during apoptosis and programmed cell death. Cell death upon expression of various human neurotoxic proteins has been characterized in yeast, revealing neurotoxic protein-specific differences. This review summarizes how mitochondria are affected in these neurotoxic yeast models, and how they are involved in the execution and prevention of cell death. I will discuss to which extent this mimics the situation in other neurotoxic model systems, and how this may contribute to a better understanding of the mitochondrial roles in the human disorders.

Mitochondrion-mediated cell death: dissecting yeast apoptosis for a better understanding of neurodegeneration

International Nuclear Information System (INIS)

Braun, Ralf J.

2012-01-01

Mitochondrial damage and dysfunction are common hallmarks for neurodegenerative disorders, including Alzheimer, Parkinson, Huntington diseases, and the motor neuron disorder amyotrophic lateral sclerosis. Damaged mitochondria pivotally contribute to neurotoxicity and neuronal cell death in these disorders, e.g., due to their inability to provide the high energy requirements for neurons, their generation of reactive oxygen species (ROS), and their induction of mitochondrion-mediated cell death pathways. Therefore, in-depth analyses of the underlying molecular pathways, including cellular mechanisms controlling the maintenance of mitochondrial function, is a prerequisite for a better understanding of neurodegenerative disorders. The yeast Saccharomyces cerevisiae is an established model for deciphering mitochondrial quality control mechanisms and the distinct mitochondrial roles during apoptosis and programmed cell death. Cell death upon expression of various human neurotoxic proteins has been characterized in yeast, revealing neurotoxic protein-specific differences. This review summarizes how mitochondria are affected in these neurotoxic yeast models, and how they are involved in the execution and prevention of cell death. I will discuss to which extent this mimics the situation in other neurotoxic model systems, and how this may contribute to a better understanding of the mitochondrial roles in the human disorders.

Intracellular trehalose and sorbitol synergistically promoting cell viability of a biocontrol yeast, Pichia anomala, for aflatoxin reduction.

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Hua, Sui Sheng T; Hernlem, Bradley J; Yokoyama, Wallace; Sarreal, Siov Bouy L

2015-05-01

Pichia anomala (Wickerhamomyces anomalus) WRL-076 was discovered by a visual screening bioassay for its antagonism against Aspergillus flavus. The yeast was shown to significantly inhibit aflatoxin production and the growth of A. flavus. P. anomala is a potential biocontrol agent for reduction of aflatoxin in the food chain. Maintaining the viability of biocontrol agents in formulated products is a great challenge for commercial applications. Four media, NYG, NYGS, NYGT and NYGST are described which support good growth of yeast cells and were tested as storage formulations. Post growth supplement of 5 % trehalose to NYGST resulted in 83 % viable yeast cells after 12 months in cold storage. Intracellular sorbitol and trehalose concentrations were determined by HPLC analysis at the beginning of the storage and at the end of 12 month. Correlation of cell viability to both trehalose and sorbitol suggested a synergistic effect. Bonferroni (Dunn) t Test, Tukey's Studentized Range (HSD) Test and Duncan's Multiple Range Test, all showed that yeast cell viability in samples with both intracellular trehalose and sorbitol were significantly higher than those with either or none, at a 95 % confidence level. DiBAC4(5) and CFDA-AM were used as the membrane integrity fluorescent stains to create a two-color vital staining scheme with red and green fluorescence, respectively. Yeast cells stored in formulations NYG and NYGS with no detectable trehalose, displayed mostly red fluorescence. Yeast cells in NYGST+5T showed mostly green fluorescence.

Untangling the Roles of Anti-Apoptosis in Regulating Programmed Cell Death using Humanized Yeast Cells

International Nuclear Information System (INIS)

Clapp, Caitlin; Portt, Liam; Khoury, Chamel; Sheibani, Sara; Eid, Rawan; Greenwood, Matthew; Vali, Hojatollah; Mandato, Craig A.; Greenwood, Michael T.

2012-01-01

Genetically programmed cell death (PCD) mechanisms, including apoptosis, are important for the survival of metazoans since it allows, among things, the removal of damaged cells that interfere with normal function. Cell death due to PCD is observed in normal processes such as aging and in a number of pathophysiologies including hypoxia (common causes of heart attacks and strokes) and subsequent tissue reperfusion. Conversely, the loss of normal apoptotic responses is associated with the development of tumors. So far, limited success in preventing unwanted PCD has been reported with current therapeutic approaches despite the fact that inhibitors of key apoptotic inducers such as caspases have been developed. Alternative approaches have focused on mimicking anti-apoptotic processes observed in cells displaying increased resistance to apoptotic stimuli. Hormesis and pre-conditioning are commonly observed cellular strategies where sub-lethal levels of pro-apoptotic stimuli lead to increased resistance to higher or lethal levels of stress. Increased expression of anti-apoptotic sequences is a common mechanism mediating these protective effects. The relevance of the latter observation is exemplified by the observation that transgenic mice overexpressing anti-apoptotic genes show significant reductions in tissue damage following ischemia. Thus strategies aimed at increasing the levels of anti-apoptotic proteins, using gene therapy or cell penetrating recombinant proteins are being evaluated as novel therapeutics to decrease cell death following acute periods of cell death inducing stress. In spite of its functional and therapeutic importance, more is known regarding the processes involved in apoptosis than anti-apoptosis. The genetically tractable yeast Saccharomyces cerevisiae has emerged as an exceptional model to study multiple aspects of PCD including the mitochondrial mediated apoptosis observed in metazoans. To increase our knowledge of the process of anti

Antagonistic Activity of Nocardia brasiliensis PTCC 1422 Against Isolated Enterobacteriaceae from Urinary Tract Infections.

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Jalali, Hossnieh Kafshdar; Salamatzadeh, Abdolreza; Jalali, Arezou Kafshdar; Kashani, Hamed Haddad; Asbchin, Salman Ahmadi; Issazadeh, Khosro

2016-03-01

The main drawback of current antibiotic therapies is the emergence and rapid increase in antibiotic resistance. Nocardiae are aerobic, Gram-positive, catalase-positive, non-motile actinomycetes. Nocardia brasiliensis was reported as antibiotic producer. The purpose of the study was to determine antibacterial activity of N. brasiliensis PTCC 1422 against isolated Enterobacteriaceae from urinary tract infections (UTIs). The common bacteria from UTIs were isolated from hospital samples. Antimicrobial susceptibility test was performed for the isolated pathogens using Kirby-Bauer disk diffusion method according to clinical and Laboratory Standards Institute guideline. Antagonistic activity of N. brasiliensis PTCC 1422 was examined with well diffusion methods. Supernatant of N. brasiliensis PTCC 1422 by submerged culture was analyzed with gas chromatography-mass spectrometry. Isolated strains included Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Proteus mirabilis. The most common pathogen isolated was E. coli (72.5%). Bacterial isolates revealed the presence of high levels of antimicrobial resistances to ceftriaxone and low levels of resistance to cephalexin. Supernatant of N. brasiliensis PTCC 1422 showed antibacterial activity against all of the isolated microorganisms in well diffusion method. The antibiotic resistance among the uropathogens is an evolving process, so a routine surveillance to monitor the etiologic agents of UTI and the resistance pattern should be carried out timely to choose the most effective empirical treatment by the physicians. Our present investigation indicates that the substances present in the N. brasiliensis PTCC 1422 could be used to inhibit the growth of human pathogen. Antibacterial resistance among bacterial uropathogen is an evolving process. Therefore, in the field on the need of re-evaluation of empirical treatment of UTIs, our present. The study has demonstrated that N. brasiliensis PTCC 1422 has a high potential

Immobilization of yeast cells with ionic hydrogel carriers by adhesion-multiplication.

Science.gov (United States)

Zhaoxin, L; Fujimura, T

2000-12-01

The mixture of an ionic monomer, 2-acrylamido 2-methylpropanesulfonic acid (TBAS), and a series of poly(ethylene glycol) dimethacrylate (nG) monomers were copolymerized with 60Co gamma-rays, and the produced ionic hydrogel polymers were used for immobilization of yeast cells. The cells were adhered onto the surface of the hydrogel polymers and intruded into the interior of the polymers with growing. The immobilized yeast cells with these hydrogel polymers had higher ethanol productivity than that of free cells. The yield of ethanol with poly(TBAS-14G) carrier was the highest and increased by 3.5 times compared to the free cells. It was found that the ethanol yield increased with the increase of glycol number in poly(ethylene glycol) dimethacrylate. The state of the immobilized cells was observed with microscope, and it was also found that the difference in the ethanol productivity is mainly due to the difference in the internal structure and properties of polymer carrier, such as surface charge, hydrophilicity, and swelling ability of polymer carrier.

Immobilization of yeast cells on hydrogel carriers obtained by radiation-induced polymerization

International Nuclear Information System (INIS)

Luzhao Xin; Carenza, M.; Kaetsu, Isao; Kumakura, Minoru; Yoshida, Masaru; Fujimura, Takashi

1992-01-01

Polymer hydrogels were obtained by radiation-induced copolymerization at -78 o C of aqueous solutions of acrylic and methacrylic esters. The matrices were characterized by equilibrium water content measurements, by optical microscopy observations and by scanning electron microscopy analysis. Yeast cells were immobilized on these hydrogels and the ethanol productivity by batch fermentation was determined. Matrix hydrophilicity and porosity were found to deeply influence the adhesion of yeast cells and, hence, the ethanol productivity. The latter as well as other physico-chemical properties were also affected by the presence of a crosslinking agent added in small amounts to the polymerizating mixture. (author)

In Vivo and In Vitro Toxicity Evaluation of Hydroethanolic Extract of Kalanchoe brasiliensis (Crassulaceae Leaves

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Aldilane Gonçalves Fonseca

2018-01-01

Full Text Available The species Kalanchoe brasiliensis, known as “Saião,” has anti-inflammatory, antimicrobial, and antihistamine activities. It also has the quercetin and kaempferol flavonoids, which exert their therapeutic activities. With extensive popular use besides the defined therapeutical properties, the study of possible side effects is indispensable. The objective of this study is to evaluate the toxicity in vitro and in vivo from the hydroethanolic extract of the leaves of K. brasiliensis. The action of the extract (concentrations from 0.1 to 1000 uL/100 uL in normal and tumor cells was evaluated using the MTT method. Acute toxicity and subchronic toxicity were evaluated in mice with doses of 250 to 1000 mg/kg orally, following recognized protocols. The in vitro results indicated cytotoxic activity for 3T3 cell line (normal and 786-0 (kidney carcinoma, showing the activity to be concentration-dependent, reaching 92.23% cell inhibition. In vivo, the extract showed no significant toxicity; only liver changes related to acute toxicity and some signs of liver damage, combining biochemical and histological data. In general, the extract showed low or no toxicity, introducing itself as safe for use with promising therapeutic potential.

Interaction Between Yeasts and Zinc

Science.gov (United States)

Nicola, Raffaele De; Walker, Graeme

Zinc is an essential trace element in biological systems. For example, it acts as a cellular membrane stabiliser, plays a critical role in gene expression and genome modification and activates nearly 300 enzymes, including alcohol dehydrogenase. The present chapter will be focused on the influence of zinc on cell physiology of industrial yeast strains of Saccharomyces cerevisiae, with special regard to the uptake and subsequent utilisation of this metal. Zinc uptake by yeast is metabolism-dependent, with most of the available zinc translocated very quickly into the vacuole. At cell division, zinc is distributed from mother to daughter cells and this effectively lowers the individual cellular zinc concentration, which may become zinc depleted at the onset of the fermentation. Zinc influences yeast fermentative performance and examples will be provided relating to brewing and wine fermentations. Industrial yeasts are subjected to several stresses that may impair fermentation performance. Such stresses may also impact on yeast cell zinc homeostasis. This chapter will discuss the practical implications for the correct management of zinc bioavailability for yeast-based biotechnologies aimed at improving yeast growth, viability, fermentation performance and resistance to environmental stresses

Nocardia brasiliensis endophthalmitis in a patient with an exposed Ahmed glaucoma drainage implant.

Science.gov (United States)

Stewart, Michael W; Bolling, James P; Bendel, Rick E

2013-01-01

To report a case of endophthalmitis due to Nocardia brasiliensis in an eye with an exposed, infected Ahmed glaucoma drainage implant (GDI). Retrospective case report. A patient with an exposed GDI experienced recurrent episodes of endophthalmitis despite repeated intravitreal injections of antibiotics and steroids. The tube was initially repositioned and finally removed. Whereas repeated cultures from the anterior chamber and vitreous were negative, cultures from the removed tube grew Nocardia brasiliensis. Despite oral trimethoprim-sulfamethoxazole and intravitreal amikacin the eye became phthisical and lost light perception. An exposed GDI may lead to endophthalmitis due to Nocardia brasiliensis and may require explantation to establish a diagnosis.

Chromosome homogeneity in populations of Triatoma brasiliensis Neiva 1911 (Hemiptera - Reduviidae - Triatominae

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Panzera Francisco

2000-01-01

Full Text Available Triatoma brasiliensis is the most important vector of Chagas disease in the semiarid zone of the Northeast of Brazil. Several authors have reported the occurrence of four chromatic patterns with morphological, ecological, and genetic differences. In order to determine the existence of cytogenetic differentiation between these chromatic forms, we analyzed their karyotypes and the chromosome behavior during the male meiotic process. Triatoma brasiliensis shows distinct and specific chromosome characteristics, which differ from those observed in all other triatomine species. However, no cytogenetic differences were observed between the four chromatic forms of T. brasiliensis. The lack of chromosome differentiation among them could indicate that the populations of this species are in a process of differentiation that does not involve their chromosomal organization.

The effect of royal sun agaricus, Agaricus brasiliensis S. Wasser et al., extract on methyl methanesulfonate caused genotoxicity in Drosophila melanogaster.

Science.gov (United States)

Savić, Tatjana; Patenković, Aleksandra; Soković, Marina; Glamoclija, Jasmina; Andjelković, Marko; van Griensven, Leo J L D

2011-01-01

The effect of culinary-medicinal Royal Sun Agaricus (Agaricus brasiliensis) hot water extract on methyl methane sulfonate (MMS) induced mutagenicity/genotoxity in Drosophila melanogaster was studied using a quick and broadly applicable in vivo assay, i.e., the wing somatic mutation and recombination test. We used 2nd instar larvae, trans-heterozygous for the third chromosome recessive markers, i.e., multiple wing hairs (mvh) and flare-3 [flr (3)], and fed them for 24 h with the aqueous extract of A. brasiliensis. For antigenotoxicity studies a 24-h pretreatment with the extract was done, followed by a 48-h treatment of the then 3rd instar larvae with MMS. The frequency of mutations of the wing blade changes (i.e., of the number of wing spots of different sizes) induced in somatic cells was determined as a parameter of genetic changes of the wing imaginal discs. The results showed that A. brasiliensis extract did not cause any genotoxic or mutagenic effects. No antigenotoxic and/or protective effect against the induction of mutations by MMS was observed. Instead, a possible enhanced mitotic recombination frequency by MMS was seen after pretreatment of the larvae with A. brasiliensis extract. Possible mechanisms of action are discussed.

Tratamentos térmicos do calxisto para uso como camada de cobertura no cultivo de Agaricus brasiliensis Thermal treatments on lime schist casing layer for Agaricus brasiliensis cultivation

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Nelson Barros Colauto

2010-07-01

Full Text Available A escolha da camada de cobertura é uma das mais importantes etapas do cultivo de Agaricus brasiliensis. Apesar dessa importância, poucos estudos relatam o uso de diferentes tratamentos térmicos para o controle da microbiota em camadas de cobertura alternativas. Assim, o objetivo deste trabalho foi avaliar o efeito da pasteurização e da autoclavagem do material alternativo calxisto para utilização como camada de cobertura no cultivo de A. brasiliensis. O fungo foi inicialmente crescido em grãos de trigo e transferido para meio de cultivo previamente compostado. Após a completa colonização, a camada de cobertura (calxisto pasteurizada ou autoclavada foi adicionada. Avaliaram-se a eficiência biológica, o número e a biomassa de cogumelos produzidos e o fluxo de produção. Concluiu-se que a camada de cobertura com calxisto autoclavado reduzem o tempo de produção, a eficiência biológica e o número e a biomassa de cogumelos cultivados. Entretanto, a camada de cobertura com o calxisto pasteurizado é a mais eficiente para o cultivo de A. brasiliensis.Casing layer choice is one of the most important phases on Agaricus brasiliensis cultivation. Besides the importance of it few studies report the use of different heat treatments to control the microbiota in alternative casing layers. Thus, the objective of this work was to evaluate the effect of pasteurized or autoclaved lime schist as an alternative casing layer on A. brasiliensis cultivation. The fungus was previously grown on wheat grains and transferred to a substratum previously composted. After substratum mycelium colonization a pasteurized or autoclaved lime schist casing layer was added on. It was evaluated the biological efficiency, the number and mass of produced mushroom and the production flush along cultivation. It was concluded that autoclaved lime schist casing layer decreases period of production, biological efficiency, number and mass of cultivated mushrooms. However

Recent advances in yeast cell-surface display technologies for waste biorefineries.

Science.gov (United States)

Liu, Zhuo; Ho, Shih-Hsin; Hasunuma, Tomohisa; Chang, Jo-Shu; Ren, Nan-Qi; Kondo, Akihiko

2016-09-01

Waste biorefinery aims to maximize the output of value-added products from various artificial/agricultural wastes by using integrated bioprocesses. To make waste biorefinery economically feasible, it is thus necessary to develop a low-cost, environment-friendly technique to perform simultaneous biodegradation and bioconversion of waste materials. Cell-surface display engineering is a novel, cost-effective technique that can auto-immobilize proteins on the cell exterior of microorganisms, and has been applied for use with waste biofinery. Through tethering different enzymes (e.g., cellulase, lipase, and protease) or metal-binding peptides on cell surfaces, various yeast strains can effectively produce biofuels and biochemicals from sugar/protein-rich waste materials, catalyze waste oils into biodiesels, or retrieve heavy metals from wastewater. This review critically summarizes recent applications of yeast cell-surface display on various types of waste biorefineries, highlighting its potential and future challenges with regard to commercializing this technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of Myrmeleon brasiliensis (Navas) (Neuroptera, Myrmeleontidae), in laboratory, with different natural diets

Energy Technology Data Exchange (ETDEWEB)

Missirian, Giani L.B. [Centro Universitario da Grande Dourados, MS (Brazil). Curso de Ciencias Biologicas; Uchoa-Fernandes, Manoel A. [Universidade Federal da Grande Dourados, MS (Brazil). Faculdade de Ciencias Biologicas e Ambientais]. E-mail: uchoa.fernandes@ufgd.edu.br; Fischer, Erich [Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil). Dept. de Biologia

2006-07-01

Antlions larvae are sit-and-wait predators that capture arthropod prey in conical sand pits. The aim of this paper were to determine the effect of different natural diets [leaf-cutting ants (Atta spp.), fruit fly larvae (Anastrepha spp. and Ceratitis capitata) and mixed diet (Atta spp. plus fruit fly larvae)] on the development of larvae and pupae of M. brasiliensis (Navas, 1914) and to estimate the number and size of prey caught in each instar and on each kind of diet. The average duration (days) of the second and third instars of M. brasiliensis was longer when larvae of antlion were fed with leaf-cutting ants. The diets did not affect the duration of the pupal stage nor the pupae size. The different diets did not affect the mean width of head capsule (mm), the mean weight (mg) or the mean body size (mm) in the different instars of M. brasiliensis. In the second and third instars, the larvae of M. brasiliensis fed with leaf-cutting ants consumed more prey than larvae kept on other diets. Adults whose larvae were fed fruit fly larvae were larger than adults on other diets. Although Myrmeleontidae are few studied in Brazil, these results contribute to knowledge of M. brasiliensis biology, but also suggest the need of studies about the development of larvae and pupae in natural environments. (author)

Ethanol production potential from fermented rice noodle wastewater treatment using entrapped yeast cell sequencing batch reactor

Science.gov (United States)

Siripattanakul-Ratpukdi, Sumana

2012-03-01

Fermented rice noodle production generates a large volume of starch-based wastewater. This study investigated the treatment of the fermented rice noodle wastewater using entrapped cell sequencing batch reactor (ECSBR) compared to traditional sequencing batch reactor (SBR). The yeast cells were applied because of their potential to convert reducing sugar in the wastewater to ethanol. In present study, preliminary treatment by acid hydrolysis was performed. A yeast culture, Saccharomyces cerevisiae, with calcium alginate cell entrapment was used. Optimum yeast cell loading in batch experiment and fermented rice noodle treatment performances using ECSBR and SBR systems were examined. In the first part, it was found that the cell loadings (0.6-2.7 × 108 cells/mL) did not play an important role in this study. Treatment reactions followed the second-order kinetics with the treatment efficiencies of 92-95%. In the second part, the result showed that ECSBR performed better than SBR in both treatment efficiency and system stability perspectives. ECSBR maintained glucose removal of 82.5 ± 10% for 5-cycle treatment while glucose removal by SBR declined from 96 to 40% within the 5-cycle treatment. Scanning electron microscopic images supported the treatment results. A number of yeast cells entrapped and attached onto the matrix grew in the entrapment matrix.

Lactic acid-producing yeast cells having nonfunctional L- or D-lactate:ferricytochrome C oxidoreductase cells

Science.gov (United States)

Miller, Matthew [Boston, MA; Suominen, Pirkko [Maple Grove, MN; Aristidou, Aristos [Highland Ranch, CO; Hause, Benjamin Matthew [Currie, MN; Van Hoek, Pim [Camarillo, CA; Dundon, Catherine Asleson [Minneapolis, MN

2012-03-20

Yeast cells having an exogenous lactate dehydrogenase gene ae modified by reducing L- or D-lactate:ferricytochrome c oxidoreductase activity in the cell. This leads to reduced consumption of lactate by the cell and can increase overall lactate yields in a fermentation process. Cells having the reduced L- or D-lactate:ferricytochrome c oxidoreductase activity can be screened for by resistance to organic acids such as lactic or glycolic acid.

Radiation stimulation of yeast crops for increasing output of alcohol and baker yeasts

International Nuclear Information System (INIS)

Vlad, E.; Marsheu, P.

1974-01-01

The purpose of this study was to stimulate by gamma radiation the existing commercial types of yeast so as to obtain yeasts that would better reflect the substrate and have improved reproductive capacity. The experiments were conducted under ordinary conditions using commercial yeasts received from one factory producing alcohol and bakery yeasts and isolated as pure cultures. Irradiating yeast cultures with small doses (up to 10 krad) was found to stimulate the reproduction and fermenting activity of yeast cells as manifested in increased accumulation of yeast biomass and greater yield of ethyl alcohol. (E.T.)

Structure, cell wall elasticity and polysaccharide properties of living yeast cells, as probed by AFM

International Nuclear Information System (INIS)

Alsteens, David; Dupres, Vincent; Evoy, Kevin Mc; Dufrene, Yves F; Wildling, Linda; Gruber, Hermann J

2008-01-01

Although the chemical composition of yeast cell walls is known, the organization, assembly, and interactions of the various macromolecules remain poorly understood. Here, we used in situ atomic force microscopy (AFM) in three different modes to probe the ultrastructure, cell wall elasticity and polymer properties of two brewing yeast strains, i.e. Saccharomyces carlsbergensis and S. cerevisiae. Topographic images of the two strains revealed smooth and homogeneous cell surfaces, and the presence of circular bud scars on dividing cells. Nanomechanical measurements demonstrated that the cell wall elasticity of S. carlsbergensis is homogeneous. By contrast, the bud scar of S. cerevisiae was found to be stiffer than the cell wall, presumably due to the accumulation of chitin. Notably, single molecule force spectroscopy with lectin-modified tips revealed major differences in polysaccharide properties of the two strains. Polysaccharides were clearly more extended on S. cerevisiae, suggesting that not only oligosaccharides, but also polypeptide chains of the mannoproteins were stretched. Consistent with earlier cell surface analyses, these findings may explain the very different aggregation properties of the two organisms. This study demonstrates the power of using multiple complementary AFM modalities for probing the organization and interactions of the various macromolecules of microbial cell walls

Sporotrichosis in Rio de Janeiro, Brazil: Sporothrix brasiliensis is associated with atypical clinical presentations.

Science.gov (United States)

Almeida-Paes, Rodrigo; de Oliveira, Manoel Marques Evangelista; Freitas, Dayvison Francis Saraiva; do Valle, Antônio Carlos Francesconi; Zancopé-Oliveira, Rosely Maria; Gutierrez-Galhardo, Maria Clara

2014-09-01

There have been several recent changes in the taxonomy of Sporothrix schenckii as well as new observations regarding the clinical aspects of sporotrichosis. In this study, we determined the identification of the Sporothrix species associated with both classic and unusual clinical aspects of sporotrichosis observed in the endemic area of sporotrichosis in Rio de Janeiro, Brazil. To verify whether S. brasiliensis is associated with clinical manifestations of sporotrichosis, a cross-sectional study was performed in which Sporothrix isolates from 50 patients with different clinical manifestations were analyzed and their isolates were studied by phenotypic and genotypic methods. Data from these patients revealed a distinct clinical picture and therapeutic response in infections caused by Sporothrix brasiliensis (n = 45) compared to patients with S. schenckii sensu stricto (n = 5). S. brasiliensis was associated with disseminated cutaneous infection without underlying disease, hypersensitivity reactions, and mucosal infection, whereas patients with S. schenckii presented with less severe and more often localized disease, similar to the majority of previously described sporotrichosis cases. Interestingly, S. brasiliensis-infected patients overall required shorter durations of itraconazole (median 16 weeks) compared to the individuals with S. schenckii (median 24 weeks). These findings suggest that Sporothrix species are linked to different clinical manifestations of sporotrichosis and that S. brasiliensis is effectively treated with oral itraconazole.

Evidence for positive selection in putative virulence factors within the Paracoccidioides brasiliensis species complex.

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Daniel R Matute

Full Text Available Paracoccidioides brasiliensis is a dimorphic fungus that is the causative agent of paracoccidioidomycosis, the most important prevalent systemic mycosis in Latin America. Recently, the existence of three genetically isolated groups in P. brasiliensis was demonstrated, enabling comparative studies of molecular evolution among P. brasiliensis lineages. Thirty-two gene sequences coding for putative virulence factors were analyzed to determine whether they were under positive selection. Our maximum likelihood-based approach yielded evidence for selection in 12 genes that are involved in different cellular processes. An in-depth analysis of four of these genes showed them to be either antigenic or involved in pathogenesis. Here, we present evidence indicating that several replacement mutations in gp43 are under positive balancing selection. The other three genes (fks, cdc42 and p27 show very little variation among the P. brasiliensis lineages and appear to be under positive directional selection. Our results are consistent with the more general observations that selective constraints are variable across the genome, and that even in the genes under positive selection, only a few sites are altered. We present our results within an evolutionary framework that may be applicable for studying adaptation and pathogenesis in P. brasiliensis and other pathogenic fungi.

Magnetically responsive yeast cells: methods of preparation and applications

Czech Academy of Sciences Publication Activity Database

Šafařík, Ivo; Maděrová, Zdeňka; Pospišková, K.; Horská, Kateřina; Šafaříková, Miroslava

2015-01-01

Roč. 32, č. 1 (2015), s. 227-237 ISSN 0749-503X R&D Projects: GA MŠk(CZ) LD13023; GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : yeast cells * Saccharomyces * Kluyveromyces * Rhodotorula * Yarrowia * magnetic modification Subject RIV: CE - Biochemistry Impact factor: 2.259, year: 2015

In vitro activities of DA-7157 and DA-7218 against Mycobacterium tuberculosis and Nocardia brasiliensis.

Science.gov (United States)

Vera-Cabrera, Lucio; Gonzalez, Eva; Rendon, Adrian; Ocampo-Candiani, Jorge; Welsh, Oliverio; Velazquez-Moreno, Victor M; Choi, Sung Hak; Molina-Torres, Carmen

2006-09-01

The in vitro activities of DA-7157, a novel oxazolidinone, against clinical isolates of Nocardia brasiliensis and Mycobacterium tuberculosis were determined. Equal MIC(50)s and MIC(90)s (0.25 and 0.5 microg/ml, respectively) were found for susceptible and multidrug-resistant isolates of M. tuberculosis. The N. brasiliensis isolates showed an MIC(90) of 1 microg/ml and an MIC(50) of 1 microg/ml. The DA-7157 prodrug, DA-7218, exhibited similar MICs for M. tuberculosis but fivefold-higher MICs for N. brasiliensis.

Senecio brasiliensis (Asteraceae poisoning in Murrah buffaloes in Rio Grande do Sul Intoxicação natural por Senecio brasiliensis (Asteraceae em bubalinos no Rio Grande do Sul

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André M.R. Corrêa

2008-03-01

Full Text Available Thirteen (14.4% out of 90 Murrah buffaloes (Bubalus bubalis became ill after con-sumption of Senecio brasiliensis, and 11 (12.2% of them died. The buffaloes were kept in a highly Senecio brasiliensis infested area. The poisoning occurred in June-August 2006 on a farm in the county of Nova Prata, Rio Grande do Sul, southern Brazil. Clinical signs included weakness, apathy, progressive weight loss, permanent decubitus, and diarrhea. Necropsy was performed in 2 of the 11 buffaloes that died. The pathological findings were typical of poisoning by pyrrolizidine alkaloids. High infestation of pastures with S. brasiliensis, severe drought, and consequent starvation were the main epidemiological factors associated with the poisoning here described.Descreve-se a ocorrência de um surto de intoxicação espontânea por Senecio brasiliensis em búfalos Murrah (Bubalus bubalis em uma propriedade localizada no município de Nova Prata, Estado do Rio Grande do Sul, no período de junho a agosto de 2006. De um total de 90 búfalos, 13 adoeceram e 11 morreram. Os animais eram mantidos em áreas de pastoreio altamente infestadas por S. brasiliensis. Os principais sinais clínicos relatados foram letargia, apatia, emagrecimento progressivo, diarréia e decúbito permanente. Necropsia foi feita em dois dos 11 animais mortos. As lesões foram características de intoxicações por alcalóides pirrolizidínicos. A grande quantidade da planta, forte estiagem e desnutrição conseqüente foram os principais achados epidemiológicos associados com a mortalidade.

Nocardia brasiliensis in Italy: a nine-year experience.

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Farina, Claudio; Andrini, Laura; Bruno, Gianfranco; Sarti, Mario; Tripodi, Marie Françoise; Utili, Riccardo; Boiron, Patrick

2007-01-01

In the past, no case reports concerning N. brasiliensis infections were published from Italy. We now report 4 cases observed during 1998-2006 in 4 Italian patients, 1 immunosuppressed and 3 immunocompetent.

Alterations in Aspergillus brasiliensis (niger) ATCC 9642 membranes associated to metabolism modifications during application of low-intensity electric current.

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Velasco-Alvarez, Nancy; Gutiérrez-Rojas, Mariano; González, Ignacio

2017-12-01

The effects of electric current on membranes associated with metabolism modifications in Aspergillus brasiliensis (niger) ATCC 9642 were studied. A 450-mL electrochemical cell with titanium ruthenium-oxide coated electrodes and packed with 15g of perlite, as inert support, was inoculated with A. brasiliensis spores and incubated in a solid inert-substrate culture (12 d; 30°C). Then, 4.5days after starting the culture, a current of 0.42mAcm -2 was applied for 24h. The application of low-intensity electric current increased the molecular oxygen consumption rate in the mitochondrial respiratory chain, resulting in high concentrations of reactive oxygen species, promoting high lipoperoxidation levels, according to measured malondialdehyde, and consequent alterations in membrane permeability explained the high n-hexadecane (HXD) degradation rates observed here (4.7-fold higher than cultures without current). Finally, cell differentiation and spore production were strongly stimulated. The study contributes to the understanding of the effect of current on the cell membrane and its association with HXD metabolism. Copyright © 2017. Published by Elsevier B.V.

Studying p53 family proteins in yeast: Induction of autophagic cell death and modulation by interactors and small molecules

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Leão, Mariana; Gomes, Sara; Bessa, Cláudia; Soares, Joana; Raimundo, Liliana [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal); Monti, Paola; Fronza, Gilberto [Mutagenesis Unit, Istituto di Ricerca e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST-Istituto Nazionale per la Ricerca sul Cancro, 16132 Genoa (Italy); Pereira, Clara [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal); Saraiva, Lucília, E-mail: lucilia.saraiva@ff.up.pt [REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n. 164, 4050-313 Porto (Portugal)

2015-01-01

In this work, the yeast Saccharomyces cerevisiae was used to individually study human p53, p63 (full length and truncated forms) and p73. Using this cell system, the effect of these proteins on cell proliferation and death, and the influence of MDM2 and MDMX on their activities were analyzed. When expressed in yeast, wild-type p53, TAp63, ΔNp63 and TAp73 induced growth inhibition associated with S-phase cell cycle arrest. This growth inhibition was accompanied by reactive oxygen species production and autophagic cell death. Furthermore, they stimulated rapamycin-induced autophagy. On the contrary, none of the tested p53 family members induced apoptosis either per se or after apoptotic stimuli. As previously reported for p53, also TAp63, ΔNp63 and TAp73 increased actin expression levels and its depolarization, suggesting that ACT1 is also a p63 and p73 putative yeast target gene. Additionally, MDM2 and MDMX inhibited the activity of all tested p53 family members in yeast, although the effect was weaker on TAp63. Moreover, Nutlin-3a and SJ-172550 were identified as potential inhibitors of the p73 interaction with MDM2 and MDMX, respectively. Altogether, the yeast-based assays herein developed can be envisaged as a simplified cell system to study the involvement of p53 family members in autophagy, the modulation of their activities by specific interactors (MDM2 and MDMX), and the potential of new small molecules to modulate these interactions. - Highlights: • p53, p63 and p73 are individually studied in the yeast S. cerevisiae. • p53 family members induce ROS production, cell cycle arrest and autophagy in yeast. • p53 family members increase actin depolarization and expression levels in yeast. • MDM2 and MDMX inhibit the activity of p53 family members in yeast. • Yeast can be a useful tool to study the biology and drugability of p53, p63 and p73.

Studying p53 family proteins in yeast: Induction of autophagic cell death and modulation by interactors and small molecules

International Nuclear Information System (INIS)

Leão, Mariana; Gomes, Sara; Bessa, Cláudia; Soares, Joana; Raimundo, Liliana; Monti, Paola; Fronza, Gilberto; Pereira, Clara; Saraiva, Lucília

2015-01-01

In this work, the yeast Saccharomyces cerevisiae was used to individually study human p53, p63 (full length and truncated forms) and p73. Using this cell system, the effect of these proteins on cell proliferation and death, and the influence of MDM2 and MDMX on their activities were analyzed. When expressed in yeast, wild-type p53, TAp63, ΔNp63 and TAp73 induced growth inhibition associated with S-phase cell cycle arrest. This growth inhibition was accompanied by reactive oxygen species production and autophagic cell death. Furthermore, they stimulated rapamycin-induced autophagy. On the contrary, none of the tested p53 family members induced apoptosis either per se or after apoptotic stimuli. As previously reported for p53, also TAp63, ΔNp63 and TAp73 increased actin expression levels and its depolarization, suggesting that ACT1 is also a p63 and p73 putative yeast target gene. Additionally, MDM2 and MDMX inhibited the activity of all tested p53 family members in yeast, although the effect was weaker on TAp63. Moreover, Nutlin-3a and SJ-172550 were identified as potential inhibitors of the p73 interaction with MDM2 and MDMX, respectively. Altogether, the yeast-based assays herein developed can be envisaged as a simplified cell system to study the involvement of p53 family members in autophagy, the modulation of their activities by specific interactors (MDM2 and MDMX), and the potential of new small molecules to modulate these interactions. - Highlights: • p53, p63 and p73 are individually studied in the yeast S. cerevisiae. • p53 family members induce ROS production, cell cycle arrest and autophagy in yeast. • p53 family members increase actin depolarization and expression levels in yeast. • MDM2 and MDMX inhibit the activity of p53 family members in yeast. • Yeast can be a useful tool to study the biology and drugability of p53, p63 and p73

Systematic identification of yeast cell cycle transcription factors using multiple data sources

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Li Wen-Hsiung

2008-12-01

Full Text Available Abstract Background Eukaryotic cell cycle is a complex process and is precisely regulated at many levels. Many genes specific to the cell cycle are regulated transcriptionally and are expressed just before they are needed. To understand the cell cycle process, it is important to identify the cell cycle transcription factors (TFs that regulate the expression of cell cycle-regulated genes. Results We developed a method to identify cell cycle TFs in yeast by integrating current ChIP-chip, mutant, transcription factor binding site (TFBS, and cell cycle gene expression data. We identified 17 cell cycle TFs, 12 of which are known cell cycle TFs, while the remaining five (Ash1, Rlm1, Ste12, Stp1, Tec1 are putative novel cell cycle TFs. For each cell cycle TF, we assigned specific cell cycle phases in which the TF functions and identified the time lag for the TF to exert regulatory effects on its target genes. We also identified 178 novel cell cycle-regulated genes, among which 59 have unknown functions, but they may now be annotated as cell cycle-regulated genes. Most of our predictions are supported by previous experimental or computational studies. Furthermore, a high confidence TF-gene regulatory matrix is derived as a byproduct of our method. Each TF-gene regulatory relationship in this matrix is supported by at least three data sources: gene expression, TFBS, and ChIP-chip or/and mutant data. We show that our method performs better than four existing methods for identifying yeast cell cycle TFs. Finally, an application of our method to different cell cycle gene expression datasets suggests that our method is robust. Conclusion Our method is effective for identifying yeast cell cycle TFs and cell cycle-regulated genes. Many of our predictions are validated by the literature. Our study shows that integrating multiple data sources is a powerful approach to studying complex biological systems.

Anorexia in rats infected with the nematode, Nippostrongylus brasiliensis: experimental manipulations.

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Mercer, J G; Mitchell, P I; Moar, K M; Bissett, A; Geissler, S; Bruce, K; Chappell, L H

2000-06-01

Nippostrongylus brasiliensis induces a biphasic anorexia in laboratory rats, the first phase coincident with lung invasion (ca day 2) and the second when the worms mature in the intestine (ca day 8). Using the anthelminthic, mebendazole (MBZ), N. brasiliensis infections of the rat were eliminated between the first and second anorexic episodes. This intervention prevented the expression of the second phase of anorexia. Rats exposed to a second infection with N. brasiliensis, 3 weeks after the primary infection, exhibited only a first phase anorexic response which was not influenced by MBZ termination of the primary infection. The lower cumulative food intake and weight gain of all infected rats after 8 days of infection were accompanied by elevated plasma insulin and, in some individuals, by elevated plasma leptin, compared with uninfected controls and previously-infected MBZ-treated rats. Messenger RNA levels for neuropeptide Y were higher in the hypothalamic arcuate nucleus of 8-day infected rats than in recovering MBZ-treated animals. Inoculation of rats with heat-killed N. brasiliensis larvae failed to induce anorexia and did not alter the severity of biphasic anorexia on subsequent injection of viable larvae. The first anorexic episode is therefore dependent upon viable migrating larvae. The second phase of anorexia clearly requires the continuing presence of the parasite beyond the lung phase. Viable migrating larvae are also required to confer 'resistance' to reinfection.

X-ray irradiation of yeast cells

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Masini, Alessandra; Batani, Dimitri; Previdi, Fabio; Conti, Aldo; Pisani, Francesca; Botto, Cesare; Bortolotto, Fulvia; Torsiello, Flavia; Turcu, I. C. Edmond; Allott, Ric M.; Lisi, Nicola; Milani, Marziale; Costato, Michele; Pozzi, Achille; Koenig, Michel

1997-10-01

Saccharomyces Cerevisiae yeast cells were irradiated using the soft X-ray laser-plasma source at Rutherford Laboratory. The aim was to produce a selective damage of enzyme metabolic activity at the wall and membrane level (responsible for fermentation) without interfering with respiration (taking place in mitochondria) and with nuclear and DNA activity. The source was calibrated by PIN diodes and X-ray spectrometers. Teflon stripes were chosen as targets for the UV laser, emitting X-rays at about 0.9 keV, characterized by a very large decay exponent in biological matter. X-ray doses to the different cell compartments were calculated following a Lambert-Bouguet-Beer law. After irradiation, the selective damage to metabolic activity at the membrane level was measured by monitoring CO2 production with pressure silicon detectors. Preliminary results gave evidence of pressure reduction for irradiated samples and non-linear response to doses. Also metabolic oscillations were evidenced in cell suspensions and it was shown that X-ray irradiation changed the oscillation frequency.

Extraction of nucleic acids from yeast cells and plant tissues using ethanol as medium for sample preservation and cell disruption.

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Linke, Bettina; Schröder, Kersten; Arter, Juliane; Gasperazzo, Tatiana; Woehlecke, Holger; Ehwald, Rudolf

2010-09-01

Here we report that dehydrated ethanol is an excellent medium for both in situ preservation of nucleic acids and cell disruption of plant and yeast cells. Cell disruption was strongly facilitated by prior dehydration of the ethanol using dehydrated zeolite. Following removal of ethanol, nucleic acids were extracted from the homogenate pellet using denaturing buffers. The method provided DNA and RNA of high yield and integrity. Whereas cell wall disruption was essential for extraction of DNA and large RNA molecules, smaller molecules such as tRNAs could be selectively extracted from undisrupted, ethanol-treated yeast cells. Our results demonstrate the utility of absolute ethanol for sample fixation, cell membrane and cell wall disruption, as well as preservation of nucleic acids during sample storage.

The central domain of yeast transcription factor Rpn4 facilitates degradation of reporter protein in human cells.

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Morozov, A V; Spasskaya, D S; Karpov, D S; Karpov, V L

2014-10-16

Despite high interest in the cellular degradation machinery and protein degradation signals (degrons), few degrons with universal activity along species have been identified. It has been shown that fusion of a target protein with a degradation signal from mammalian ornithine decarboxylase (ODC) induces fast proteasomal degradation of the chimera in both mammalian and yeast cells. However, no degrons from yeast-encoded proteins capable to function in mammalian cells were identified so far. Here, we demonstrate that the yeast transcription factor Rpn4 undergoes fast proteasomal degradation and its central domain can destabilize green fluorescent protein and Alpha-fetoprotein in human HEK 293T cells. Furthermore, we confirm the activity of this degron in yeast. Thus, the Rpn4 central domain is an effective interspecies degradation signal. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Yeast flocculation: New story in fuel ethanol production.

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Zhao, X Q; Bai, F W

2009-01-01

Yeast flocculation has been used in the brewing industry to facilitate biomass recovery for a long time, and thus its mechanism of yeast flocculation has been intensively studied. However, the application of flocculating yeast in ethanol production garnered attention mainly in the 1980s and 1990s. In this article, updated research progress in the molecular mechanism of yeast flocculation and the impact of environmental conditions on yeast flocculation are reviewed. Construction of flocculating yeast strains by genetic approach and utilization of yeast flocculation for ethanol production from various feedstocks were presented. The concept of self-immobilized yeast cells through their flocculation is revisited through a case study of continuous ethanol fermentation with the flocculating yeast SPSC01, and their technical and economic advantages are highlighted by comparing with yeast cells immobilized with supporting materials and regular free yeast cells as well. Taking the flocculating yeast SPSC01 as an example, the ethanol tolerance of the flocculating yeast was also discussed.

Nocardia brasiliensis-associated femorotibial osteomyelitis.

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

2014-03-01

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. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

In situ detection and distribution of inflammatory cytokines during the course of infection with Nocardia brasiliensis.

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Solis-Soto, J M; Quintanilla-Rodriguez, L E; Meester, I; Segoviano-Ramirez, J C; Vazquez-Juarez, J L; Salinas Carmona, M C

2008-05-01

Actinomycetoma, caused by the intracellular bacterium Nocardia brasiliensis, is characterized by an infiltration of several inflammatory cell populations. To explore aspects of the immune response in the pathogenesis of these bacteria we injected 10(6) CFU in footpads of BALB/c mice. After 1, 2, 3, 4, 7, 30 and 90 days immunohistochemistry was performed to compare presence and distribution of the inflammatory cytokines TNF-alpha, IL-1 beta, IL-6, IFN-gamma, IL-4, IL-10, and TGF-beta. Analysis of serial paraffin tissue sections showed strong participation and differences in distribution of cytokine-producing cells during the course of infection. Several TNF-alpha immunoreactive lymphocytes of the dermis were present during the course of the infection, but absent in the site of inflammation. During the first 4 days, IL-1 beta immunoreactivity was observed in dendritic epidermal cells and in cells surrounding the neutrophils around the grain. In later stages of infection, immunoreactive cells to this cytokine were mainly in the periphery of the microabscesses. Strong immunoreactivity was observed with IL-6 during the course of infection. Some cells in the epidermis and dermis, as well as muscle cells and several cells at the periphery of the microabscesses, showed strong IL-6 immunoreactivity. Cells immunoreactive to IL-4, IL-10, IFN-gamma and TGF-beta were present at the site of infection and, in later stages, in cells at the periphery of the microabscesses. In conclusion a mix of proinflammatory and antiinflammatory cytokines are produced at the same time by host cells. According to their distribution, inflammatory cytokines seems to have different functions during the course of infection with the intracellular bacterium N. brasiliensis.

Importance of xenarthrans in the eco-epidemiology of Paracoccidioides brasiliensis

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Pedrini Silvia CB

2009-11-01

Full Text Available Abstract 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.

Importance of xenarthrans in the eco-epidemiology of Paracoccidioides brasiliensis.

Science.gov (United States)

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

2009-11-17

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. 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. 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.

Development of Myrmeleon brasiliensis (Navás (Neuroptera, Myrmeleontidae, in laboratory, with different natural diets Desenvolvimento de Myrmeleon brasiliensis (Navás (Neuroptera, Myrmeleontidae, em laboratório, com diferentes dietas naturais

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Giani L. B. Missirian

2006-12-01

Full Text Available Antlions larvae are sit-and-wait predators that capture arthropod prey in conical sand pits. The aim of this paper were to determine the effect of different natural diets [leaf-cutting ants (Atta spp., fruit fly larvae (Anastrepha spp. and Ceratitis capitata and mixed diet (Atta spp. plus fruit fly larvae] on the development of larvae and pupae of M. brasiliensis (Navás, 1914 and to estimate the number and size of prey caught in each instar and on each kind of diet. The average duration (days of the second and third instars of M. brasiliensis was longer when larvae of antlion were fed with leaf-cutting ants. The diets did not affect the duration of the pupal stage nor the pupae size. The different diets did not affect the mean width of head capsule (mm, the mean weight (mg or the mean body size (mm in the different instars of M. brasiliensis. In the second and third instars, the larvae of M. brasiliensis fed with leaf-cutting ants consumed more prey than larvae kept on other diets. Adults whose larvae were fed fruit fly larvae were larger than adults on other diets. Although Myrmeleontidae are few studied in Brazil, these results contribute to knowledge of M. brasiliensis biology, but also suggest the need of studies about the development of larvae and pupae in natural environments.Larvas de formiga-leão são conhecidas por suas armadilhas ("funis" que constroem em solo arenoso, sob as quais esperam por suas presas. Este trabalho teve como objetivos verificar o efeito de diferentes dietas naturais [formigas-cortadeiras (Atta spp., larvas de moscas-das-frutas (Anastrepha spp. e Ceratitis capitata e dieta mista (Atta spp. e larvas de moscas-das-frutas] sobre o desenvolvimento larval e pupal de M. brasiliensis (Navás, 1914 e estimar o número e tamanho de presas capturadas, por instar larval, em cada dieta. No segundo e terceiro instares, as larvas de M. brasiliensis alimentadas com formigas-cortadeiras consumiram um número maior de presas e a

Immunogenicity is unrelated to protective immunity when induced by soluble and particulate antigens from Nocardia brasiliensis in BALB/c mice.

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Salinas-Carmona, Mario C; Ramos, Alma I; Pérez-Rivera, Isabel

2006-08-01

Cell-mediated immunity plays a major role in protection against intracellular microbes. Nocardia brasiliensis is a facultative intracellular pathogen that causes chronic actinomycetoma. In this work, we injected BALB/c mice with soluble P24 and particulate antigens from N. brasiliensis. A higher antibody titer and lymphocyte proliferation was induced by the particulate antigen than by the soluble antigen. However, five months after antigen injection, antibody concentration and lymphocyte proliferation were similar. An increase in CD45R and CD4 T cells was unrelated to protective immunity. Active immunization with soluble or particulate antigens induced complete protection during the primary immune response. This protective response was IgM mediated. The higher immunogenicity was not related to protective immunity since the particulate antigen induced protection similar to the soluble antigen. Using particulate antigens for vaccination guarantees a stronger immune response, local and systemic side effects, but not necessarily protection.

Nitrile Metabolizing Yeasts

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Bhalla, Tek Chand; Sharma, Monica; Sharma, Nitya Nand

Nitriles and amides are widely distributed in the biotic and abiotic components of our ecosystem. Nitrile form an important group of organic compounds which find their applications in the synthesis of a large number of compounds used as/in pharmaceutical, cosmetics, plastics, dyes, etc>. Nitriles are mainly hydro-lyzed to corresponding amide/acid in organic chemistry. Industrial and agricultural activities have also lead to release of nitriles and amides into the environment and some of them pose threat to human health. Biocatalysis and biotransformations are increasingly replacing chemical routes of synthesis in organic chemistry as a part of ‘green chemistry’. Nitrile metabolizing organisms or enzymes thus has assumed greater significance in all these years to convert nitriles to amides/ acids. The nitrile metabolizing enzymes are widely present in bacteria, fungi and yeasts. Yeasts metabolize nitriles through nitrilase and/or nitrile hydratase and amidase enzymes. Only few yeasts have been reported to possess aldoxime dehydratase. More than sixty nitrile metabolizing yeast strains have been hither to isolated from cyanide treatment bioreactor, fermented foods and soil. Most of the yeasts contain nitrile hydratase-amidase system for metabolizing nitriles. Transformations of nitriles to amides/acids have been carried out with free and immobilized yeast cells. The nitrilases of Torulopsis candida>and Exophiala oligosperma>R1 are enantioselec-tive and regiospecific respectively. Geotrichum>sp. JR1 grows in the presence of 2M acetonitrile and may have potential for application in bioremediation of nitrile contaminated soil/water. The nitrilase of E. oligosperma>R1 being active at low pH (3-6) has shown promise for the hydroxy acids. Immobilized yeast cells hydrolyze some additional nitriles in comparison to free cells. It is expected that more focus in future will be on purification, characterization, cloning, expression and immobilization of nitrile metabolizing

Fission yeast cells undergo nuclear division in the absence of spindle microtubules.

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Stefania Castagnetti

2010-10-01

Full Text Available Mitosis in eukaryotic cells employs spindle microtubules to drive accurate chromosome segregation at cell division. Cells lacking spindle microtubules arrest in mitosis due to a spindle checkpoint that delays mitotic progression until all chromosomes have achieved stable bipolar attachment to spindle microtubules. In fission yeast, mitosis occurs within an intact nuclear membrane with the mitotic spindle elongating between the spindle pole bodies. We show here that in fission yeast interference with mitotic spindle formation delays mitosis only briefly and cells proceed to an unusual nuclear division process we term nuclear fission, during which cells perform some chromosome segregation and efficiently enter S-phase of the next cell cycle. Nuclear fission is blocked if spindle pole body maturation or sister chromatid separation cannot take place or if actin polymerization is inhibited. We suggest that this process exhibits vestiges of a primitive nuclear division process independent of spindle microtubules, possibly reflecting an evolutionary intermediate state between bacterial and Archeal chromosome segregation where the nucleoid divides without a spindle and a microtubule spindle-based eukaryotic mitosis.

Schizosaccharomyces japonicus: the fission yeast is a fusion of yeast and hyphae.

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Niki, Hironori

2014-03-01

The clade of Schizosaccharomyces includes 4 species: S. pombe, S. octosporus, S. cryophilus, and S. japonicus. Although all 4 species exhibit unicellular growth with a binary fission mode of cell division, S. japonicus alone is dimorphic yeast, which can transit from unicellular yeast to long filamentous hyphae. Recently it was found that the hyphal cells response to light and then synchronously activate cytokinesis of hyphae. In addition to hyphal growth, S. japonicas has many properties that aren't shared with other fission yeast. Mitosis of S. japonicas is referred to as semi-open mitosis because dynamics of nuclear membrane is an intermediate mode between open mitosis and closed mitosis. Novel genetic tools and the whole genomic sequencing of S. japonicas now provide us with an opportunity for revealing unique characters of the dimorphic yeast. © 2013 The Author. Yeast Published by John Wiley & Sons Ltd.

Introduction of the yeast DNA repair gene PHR1 into normal and xeroderma pigmentosum human cells

International Nuclear Information System (INIS)

Whyte, D.B.

1988-01-01

The goal of the work described herein is to determine how UV light kills and mutates human cells. Specifically, the hypothesis to be tested states that the major cause of cell death is the cyclobutane dimer. The yeast (S. cerevisiae) enzyme photolyase provides an elegant means of dissecting the biological effects of the two lesions. Photolyase, the product of the PHR1 gene, catalyzes the visible light-dependent reversal of cyclobutane pyrimidine dimers. Introducing the gene for photolyase into human cells, which do not have a functional photoreactivation mechanism, should allow specific repair of cyclobutane pyrimidine dimers. To express the yeast DNA repair gene in human cells, the yeast PHR1 coding sequence was cloned into the mammalian expression vector pRSV4NEO-I. The resulting plasmid, pRSVPHR1, contains the coding sequence of the yeast gene, under control of transcription signals recognized by mammalian cells, and the dominant selectable gene neo. pRSVPHR1 was introduced into normal and XP SV40-transformed fibroblasts by the calcium phosphate coprecipitation technique, and G418-resistant clones were isolated. The level of PHR1 expression was determined by cytoplasmic RNA dot blots. Two clones, XP-3B and GM-20A, had high levels of expression

Use of INAA to study the determination of Se, Th, Zn, Co and Fe levels of yeast cells

International Nuclear Information System (INIS)

Czauderna, M.; Turska, M.; Sitowska, B.

1996-01-01

Differences in the effects of seleno-cystine (CySe) 2 , glutathione (GSH), Se(IV) [as SeO 2 ] and Se(VI) [as (NH 4 ) 2 SeO 4 ] on Th(IV) [as Th(CO 3 ) 2 ] uptake by the cells, Saccharomyces cerevisiae, have been studied. The Th, Se, Zn, Co and Fe levels of the yeast cells were measured by instrumental neutron activation analysis. Results obtained show that the addition of Th alone to the culture medium resulting in the Th content of the cells and the Th level of the yeast slightly decreased during the incubation. The addition of Th in combination with GSH produced a higher decrease of the Th content in comparison with the single Th dosage. During the initial 48 h of the incubation the presence of Th and Se(VI) in the medium produced a decrease of the Th level of the cells in comparison with the addition of Th alone. (CySe) 2 or SeO 2 does not produce a regular change of the Th level of the cells. Th uptake by the yeast influenced the retention of Se in the cells. In fact, the Se levels of the cells were always significantly higher when the yeast was incubated in the medium containing Th and SeO 2 or Se(VI). The enhance in the Se level of the cells rises increasing concentrations of SeO 2 in the culture medium. Th decreased the Se content of the yeast when the cells were incubated in the medium containing (CySe) 2 and Th. GSH supply in combination with Th and SeO 2 produced a very significant enhancement of the Se abundance in the cells in comparison with the single addition of SeO 2 . Se-compounds and/or Th dosages affected the Zn, Co and Fe contents of the cells. The Fe level of the yeast is below the quantitative detection limit of Fe when the cells were incubated in the medium containing Th. (Author)

Extracellular Vesicle-Associated Transitory Cell Wall Components and Their Impact on the Interaction of Fungi with Host Cells.

Science.gov (United States)

Nimrichter, Leonardo; de Souza, Marcio M; Del Poeta, Maurizio; Nosanchuk, Joshua D; Joffe, Luna; Tavares, Patricia de M; Rodrigues, Marcio L

2016-01-01

Classic cell wall components of fungi comprise the polysaccharides glucans and chitin, in association with glycoproteins and pigments. During the last decade, however, system biology approaches clearly demonstrated that the composition of fungal cell walls include atypical molecules historically associated with intracellular or membrane locations. Elucidation of mechanisms by which many fungal molecules are exported to the extracellular space suggested that these atypical components are transitorily located to the cell wall. The presence of extracellular vesicles (EVs) at the fungal cell wall and in culture supernatants of distinct pathogenic species suggested a highly functional mechanism of molecular export in these organisms. Thus, the passage of EVs through fungal cell walls suggests remarkable molecular diversity and, consequently, a potentially variable influence on the host antifungal response. On the basis of information derived from the proteomic characterization of fungal EVs from the yeasts Cryptoccocus neoformans and Candida albicans and the dimorphic fungi Histoplasma capsulatum and Paracoccidioides brasiliensis, our manuscript is focused on the clear view that the fungal cell wall is much more complex than previously thought.

Secretion of non-cell-bound phytase by the yeast Pichia kudriavzevii TY13.

Science.gov (United States)

Hellström, A; Qvirist, L; Svanberg, U; Veide Vilg, J; Andlid, T

2015-05-01

Mineral deficiencies cause several health problems in the world, especially for populations consuming cereal-based diets rich in the anti-nutrient phytate. Our aim was to characterize the phytate-degrading capacity of the yeast Pichia kudriavzevii TY13 and its secretion of phytase. The phytase activity in cell-free supernatants from cultures with 100% intact cells was 35-190 mU ml(-1) depending on the media. The Km was 0.28 mmol l(-1) and the specific phytase activity 0.32 U mg(-1) total protein. The phytase activity and secretion of extracellular non-cell-bound phytase was affected by the medium phosphate concentrations. Further, addition of yeast extract had a clearly inducing effect, resulting in over 60% of the cultures total phytase activity as non-cell-bound. Our study reveals that it is possible to achieve high extracellular phytase activity from the yeast P. kudriavzevii TY13 by proper composition of the growth medium. TY13 could be a promising future starter culture for fermented foods with improved mineral bioavailability. Using strains that secrete phytase to the food matrix may significantly improve the phytate degradation by facilitating the enzyme-to-substrate interaction. The secreted non-cell-bound phytase activities by TY13 could further be advantageous in industrial production of phytase. © 2015 The Society for Applied Microbiology.

Neofusicoccum ribis Associated with Leaf Blight on Rubber (Hevea brasiliensis in Peninsular Malaysia

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A. I. C. Nyaka Ngobisa

2013-03-01

Full Text Available Hevea brasiliensis is a natural source of rubber and an important plantation tree species in Malaysia. Leaf blight disease caused by Fusicoccum substantially reduces the growth and performance of H. brasiliensis. The aim of this study was to use a combination of both morphological characteristics and molecular data to clarify the taxonomic position of the fungus associated with leaf blight disease. Fusicoccum species were isolated from infected leaves collected from plantations at 3 widely separated locations – Selangor, Perak, and Johor states – in Peninsular Malaysia in 2010. All the isolates were identified according to their conidial patterns and DNA sequences generated from internal transcribed spacers (ITS1 and ITS2, the 5.8S rRNA, and an unknown locus (BotF15 containing microsatellite repeats. Based on taxonomic and sequence data, Neofusicoccum ribis was identified as the main cause of leaf blight disease in H. brasiliensis in commercial plantations in Malaysia. A pathogenicity trial on detached leaves further confirmed that N. ribis causes leaf blight disease. N. ribis is an important leaf pathogen, and its detection in Malaysia has important implications for future planting of H. brasiliensis.

Liquid holding recovery kinetics in yeast cells with regard to radiation quality

International Nuclear Information System (INIS)

Kim, Jin Kyu; Lee, Byoung Hun; Petin, Vladislav G.

2004-01-01

It is widely accepted that the RBE of ionizing radiation with a high linear energy transfer (LET) is dependent both on the increased probability of primary damage production (physical events) and the reduced ability of a cell for post-irradiation recovery (biological events). A relatively unexpected role of the specific repair pathways in the RBE of high-LET radiation was demonstrated for bacterial, yeast and mammalian cells. It seems to exist a common agreement that high-LET radiations produce more portion of damage that are considered to be irreversible compared with low-LET radiation such as photons. Cellular recovery and repair of radiation-induced DNA double-strand breaks (DSB) could be also dependent upon radiation quality. Studies concerning the rate of the recovery and repair from radiation damage produced with low- and high-LET radiations in cells of various origins on the survival and macromolecular level have also revealed that in general at a high ionization density, these processes may be reduced or even absent. When irradiated yeast cells are held in a liquid non-nutrient media at 30 .deg. C before planting on to a growth medium, their survival increases. This phenomena is known as liquid holding recovery (LHR). A quantitative approach describing the LHR kinetics of the yeast cells was described, which enables the estimation of the probability of the recovery per unit time and the fraction of the irreversible damage. The main goals of this study were (i) to answer the question whether or not high-LET radiation affects the recovery process itself or if it only produces a higher level of severe irreversible damage that cannot be repaired at all; (ii) to elucidate the role of irreversible damage and the probability of recovery in some rad mutants of the yeast Saccharomyces cerevisiae. In this study, the liquid-holing recovery will serve as an indicator of the cellular repair activity

Biomedical applications of yeast- a patent view, part one: yeasts as workhorses for the production of therapeutics and vaccines.

Science.gov (United States)

Roohvand, Farzin; Shokri, Mehdi; Abdollahpour-Alitappeh, Meghdad; Ehsani, Parastoo

2017-08-01

Yeasts, as Eukaryotes, offer unique features for ease of growth and genetic manipulation possibilities, making it an exceptional microbial host. Areas covered: This review provides general and patent-oriented insights into production of biopharmaceuticals by yeasts. Patents, wherever possible, were correlated to the original or review articles. The review describes applications of major GRAS (generally regarded as safe) yeasts for the production of therapeutic proteins and subunit vaccines; additionally, immunomodulatory properties of yeast cell wall components were reviewed for use of whole yeast cells as a new vaccine platform. The second part of the review will discuss yeast- humanization strategies and innovative applications. Expert opinion: Biomedical applications of yeasts were initiated by utilization of Saccharomyces cerevisiae, for production of leavened (fermented) products, and advanced to serve to produce biopharmaceuticals. Higher biomass production and expression/secretion yields, more similarity of glycosylation patterns to mammals and possibility of host-improvement strategies through application of synthetic biology might enhance selection of Pichia pastoris (instead of S. cerevisiae) as a host for production of biopharmaceutical in future. Immunomodulatory properties of yeast cell wall β-glucans and possibility of intracellular expression of heterologous pathogen/tumor antigens in yeast cells have expanded their application as a new platform, 'Whole Yeast Vaccines'.

Yeast cell factories on the horizon

DEFF Research Database (Denmark)

Nielsen, Jens

2015-01-01

For thousands of years, yeast has been used for making beer, bread, and wine. In modern times, it has become a commercial workhorse for producing fuels, chemicals, and pharmaceuticals such as insulin, human serum albumin, and vaccines against hepatitis virus and human papillomavirus. Yeast has also...... been engineered to make chemicals at industrial scale (e.g., succinic acid, lactic acid, resveratrol) and advanced biofuels (e.g., isobutanol) (1). On page 1095 of this issue, Galanie et al. (2) demonstrate that yeast can now be engineered to produce opioids (2), a major class of compounds used...

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

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Almaguer-Chávez, Janeth A; Welsh, Oliverio; Lozano-Garza, Hector G; Said-Fernández, Salvador; Romero-Díaz, Víktor J; Ocampo-Candiani, Jorge; Vera-Cabrera, Lucio

2011-10-26

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. 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. 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. 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.

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

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Ocampo-Candiani Jorge

2011-10-01

Full Text Available Abstract 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.

Cell-autonomous mechanisms of chronological aging in the yeast Saccharomyces cerevisiae

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Anthony Arlia-Ciommo

2014-05-01

Full Text Available A body of evidence supports the view that the signaling pathways governing cellular aging – as well as mechanisms of their modulation by longevity-extending genetic, dietary and pharmacological interventions - are conserved across species. The scope of this review is to critically analyze recent advances in our understanding of cell-autonomous mechanisms of chronological aging in the budding yeast Saccharomyces cerevisiae. Based on our analysis, we propose a concept of a biomolecular network underlying the chronology of cellular aging in yeast. The concept posits that such network progresses through a series of lifespan checkpoints. At each of these checkpoints, the intracellular concentrations of some key intermediates and products of certain metabolic pathways - as well as the rates of coordinated flow of such metabolites within an intricate network of intercompartmental communications - are monitored by some checkpoint-specific ′′master regulator′′ proteins. The concept envisions that a synergistic action of these master regulator proteins at certain early-life and late-life checkpoints modulates the rates and efficiencies of progression of such processes as cell metabolism, growth, proliferation, stress resistance, macromolecular homeostasis, survival and death. The concept predicts that, by modulating these vital cellular processes throughout lifespan (i.e., prior to an arrest of cell growth and division, and following such arrest, the checkpoint-specific master regulator proteins orchestrate the development and maintenance of a pro- or anti-aging cellular pattern and, thus, define longevity of chronologically aging yeast.

Cell-autonomous mechanisms of chronological aging in the yeast Saccharomyces cerevisiae.

Science.gov (United States)

Arlia-Ciommo, Anthony; Leonov, Anna; Piano, Amanda; Svistkova, Veronika; Titorenko, Vladimir I

2014-05-27

A body of evidence supports the view that the signaling pathways governing cellular aging - as well as mechanisms of their modulation by longevity-extending genetic, dietary and pharmacological interventions - are conserved across species. The scope of this review is to critically analyze recent advances in our understanding of cell-autonomous mechanisms of chronological aging in the budding yeast Saccharomyces cerevisiae . Based on our analysis, we propose a concept of a biomolecular network underlying the chronology of cellular aging in yeast. The concept posits that such network progresses through a series of lifespan checkpoints. At each of these checkpoints, the intracellular concentrations of some key intermediates and products of certain metabolic pathways - as well as the rates of coordinated flow of such metabolites within an intricate network of intercompartmental communications - are monitored by some checkpoint-specific "master regulator" proteins. The concept envisions that a synergistic action of these master regulator proteins at certain early-life and late-life checkpoints modulates the rates and efficiencies of progression of such processes as cell metabolism, growth, proliferation, stress resistance, macromolecular homeostasis, survival and death. The concept predicts that, by modulating these vital cellular processes throughout lifespan (i.e., prior to an arrest of cell growth and division, and following such arrest), the checkpoint-specific master regulator proteins orchestrate the development and maintenance of a pro- or anti-aging cellular pattern and, thus, define longevity of chronologically aging yeast.

Glyoxalase I expression pattern in Hevea brasiliensis seedlings ...

African Journals Online (AJOL)

sunny t

2016-03-16

Mar 16, 2016 ... developing tolerance to drought stress in Hevea brasiliensis. In the present study, a partial .... First strand cDNA was synthesized from total RNA by reverse transcription with oligo (dT) ..... Genetic engineering of the glyoxalase ...

Alpha-ketoglutarate enhances freeze-thaw tolerance and prevents carbohydrate-induced cell death of the yeast Saccharomyces cerevisiae.

Science.gov (United States)

Bayliak, Maria M; Hrynkiv, Olha V; Knyhynytska, Roksolana V; Lushchak, Volodymyr I

2018-01-01

Stress resistance and fermentative capability are important quality characteristics of baker's yeast. In the present study, we examined protective effects of exogenous alpha-ketoglutarate (AKG), an intermediate of the tricarboxylic acid cycle and amino acid metabolism, against freeze-thaw and carbohydrate-induced stresses in the yeast Saccharomyces cerevisiae. Growth on AKG-supplemented medium prevented a loss of viability and improved fermentative capacity of yeast cells after freeze-thaw treatment. The cells grown in the presence of AKG had higher levels of amino acids (e.g., proline), higher metabolic activity and total antioxidant capacity, and higher activities of catalase, NADP-dependent glutamate dehydrogenase and glutamine synthase compared to control ones. Both synthesis of amino acids and enhancement of antioxidant system capacity could be involved in AKG-improved freeze-thaw tolerance in S. cerevisiae. Cell viability dramatically decreased under incubation of stationary-phase yeast cells in 2% glucose or fructose solutions (in the absence of the other nutrients) as compared with incubation in distilled water or in 10 mM AKG solution. The decrease in cell viability was accompanied by acidification of the medium, and decrease in cellular respiration, aconitase activity, and levels of total protein and free amino acids. The supplementation with 10 mM AKG effectively prevented carbohydrate-induced yeast death. Protective mechanisms of AKG could be associated with the intensification of respiration and prevention of decreasing protein level as well as with direct antioxidant AKG action.

Production of fatty acid-derived oleochemicals and biofuels by synthetic yeast cell factories

DEFF Research Database (Denmark)

Zhou, Yongjin J.; Buijs, Nicolaas A; Zhu, Zhiwei

2016-01-01

Sustainable production of oleochemicals requires establishment of cell factory platform strains. The yeast Saccharomyces cerevisiae is an attractive cell factory as new strains can be rapidly implemented into existing infrastructures such as bioethanol production plants. Here we show high-level p...

Analytical model for macromolecular partitioning during yeast cell division

International Nuclear Information System (INIS)

Kinkhabwala, Ali; Khmelinskii, Anton; Knop, Michael

2014-01-01

Asymmetric cell division, whereby a parent cell generates two sibling cells with unequal content and thereby distinct fates, is central to cell differentiation, organism development and ageing. Unequal partitioning of the macromolecular content of the parent cell — which includes proteins, DNA, RNA, large proteinaceous assemblies and organelles — can be achieved by both passive (e.g. diffusion, localized retention sites) and active (e.g. motor-driven transport) processes operating in the presence of external polarity cues, internal asymmetries, spontaneous symmetry breaking, or stochastic effects. However, the quantitative contribution of different processes to the partitioning of macromolecular content is difficult to evaluate. Here we developed an analytical model that allows rapid quantitative assessment of partitioning as a function of various parameters in the budding yeast Saccharomyces cerevisiae. This model exposes quantitative degeneracies among the physical parameters that govern macromolecular partitioning, and reveals regions of the solution space where diffusion is sufficient to drive asymmetric partitioning and regions where asymmetric partitioning can only be achieved through additional processes such as motor-driven transport. Application of the model to different macromolecular assemblies suggests that partitioning of protein aggregates and episomes, but not prions, is diffusion-limited in yeast, consistent with previous reports. In contrast to computationally intensive stochastic simulations of particular scenarios, our analytical model provides an efficient and comprehensive overview of partitioning as a function of global and macromolecule-specific parameters. Identification of quantitative degeneracies among these parameters highlights the importance of their careful measurement for a given macromolecular species in order to understand the dominant processes responsible for its observed partitioning

Photomimetic effect of serotonin on yeast cells irradiated by far-UV radiation

International Nuclear Information System (INIS)

Fraikin, G.Y.; Strakhovskaya, M.G.; Rubin, L.B.

1982-01-01

The effect of serotonin on the survival of far-UV irradiated cells of the yeast Candida guilliermondii was studied. Serotonin was found to have a photomimetic property. Preincubation of cells with serotonin results in protection against far-UV inactivation, whereas the post-radiation treatment with serotonin causes a potentiation of far-UV lethality. Both effects are similar to those produced by near-UV (334 nm) radiation. The observations provide support to the previously proposed idea that photosynthesized serotonin is the underlying cause of the two effects of near-UV radiation, photoprotection and potentiation of far-UV lethality. Experiments with an excision-deficient strain of the yeast Saccharomyces cerevisiae suggest that the effect of serotonin is by its binding to DNA. (author)

Metacercárias de Neascus sp. em Geophagus brasiliensis (Perciformes: Cichlidae do rio do Peixe, Juiz de Fora, Brasil - DOI: 10.4025/actascibiolsci.v30i3.493 Neascus-type metacercariae in Geophagus brasiliensis (Perciformes: Cichlidae of Peixe river, Juiz de Fora, Brazil - DOI: 10.4025/actascibiolsci.v30i3.493

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José Luis Luque

2008-10-01

Full Text Available A metacercária de Neascus sp., causadora da doença dos pontos pretos, é descrita em espécimes de Geophagus brasiliensis coletados no Brasil. Entre março e maio de 2006, foram capturados 33 espécimes de G. brasiliensis, coletados com o auxílio de vara e anzol no Rio do Peixe, Monte Verde, município de Juiz de Fora, Estado de Minas Gerias. Dos 33 espécimes examinados, 30 (90,9% apresentaram-se parasitados por metacercárias causadoras dos pontos pretos, com intensidade média de infecção de 15,6 ± 16,1 (1 – 75. Foi observada correlação significativa entre o comprimento total de G. brasiliensis e a abundância parasitária (r = 0,459; P Neascus-type metacercariae, which cause the black spot disease, are described in specimens collected from 33 samples of Geophagus brasiliensis from the Peixe river, in Monte Verde, Juiz de Fora, state of Minas Gerais, Brazil, during March and May 2006. The main morphological features of these metacercariae are: genital primordia composed of three cell masses located in the hind body, and a median dorsal vessel of the reserve bladder around the acetabulum. Thirty fish specimens (90.9% were parasitized by metacercariae, with mean infection intensity of 15.6 ± 16.1 (1-75. Also, a positive correlation was detected between G. brasiliensis total length and the parasite abundance (r = 0.459; p < 0.01.

The digestion of yeast cell wall polysaccharides in veal calves

NARCIS (Netherlands)

Gaillard, B.D.E.; Weerden, van E.J.

1976-01-01

1. The digestibility of the cell wall polysaccharides of an alkane-grown yeast in different parts of the digestive tract of two veal calves fitted with re-entrant cannulas at the end of the ileum was studied by replacing part of the skim-milk powder of their ‘normal’, milk-substitute

Pentacyclic triterpenoids from the leaves of Terminalia brasiliensis; Triterpenoides pentaciclicos das folhas de Terminalia brasiliensis

Energy Technology Data Exchange (ETDEWEB)

Araujo, Delton Servulo; Chaves, Mariana H. [Universidade Federal do Piaui, Teresina, PI (Brazil). Dept. de Quimica]. E-mail: mariana@ufpi.br

2005-11-15

Eleven oleanane, ursane and lupane-type triterpenes were isolated from the leaves of Terminalia brasiliensis Camb, daturadiol (3{beta},6{beta}-dihydroxy-olean-12-ene), 3{beta}-hydroxy-30-norlupan-20-one, lupenone, {beta}-amyrenone, {alpha}-amyrenone, lupeol, {beta}-amyrin, {alpha}-amyrin, betulin, erythrodiol and uvaol, in addition to squalene, sitosterol and {alpha}-tocopherol. The structures of these compounds were identified by {sup 1}H and {sup 13}C NMR spectral analysis and comparison with literature data. (author)

Soft x-ray-controlled dose deposition in yeast cells: techniques, model, and biological assessment

Science.gov (United States)

Milani, Marziale; Batani, Dimitri; Conti, Aldo; Masini, Alessandra; Costato, Michele; Pozzi, Achille; Turcu, I. C. Edmond

1996-12-01

A procedure is presented to release soft x-rays onto yeast cell membrane allegedly damaging the resident enzymatic processes connected with fermentation. The damage is expected to be restricted to regulating fermentation processes without interference with respiration. By this technique fermentation is followed leading to CO2 production, and respiration resulting in global pressure measurements. A solid state pressure sensor system has been developed linked to a data acquisition system. Yeast cells cultures have been investigated at different concentrations and with different nutrients. A non-monotone response in CO2 production as a function of the delivered x-ray dose is observed.

Reconstructing the regulatory circuit of cell fate determination in yeast mating response.

Science.gov (United States)

Shao, Bin; Yuan, Haiyu; Zhang, Rongfei; Wang, Xuan; Zhang, Shuwen; Ouyang, Qi; Hao, Nan; Luo, Chunxiong

2017-07-01

Massive technological advances enabled high-throughput measurements of proteomic changes in biological processes. However, retrieving biological insights from large-scale protein dynamics data remains a challenging task. Here we used the mating differentiation in yeast Saccharomyces cerevisiae as a model and developed integrated experimental and computational approaches to analyze the proteomic dynamics during the process of cell fate determination. When exposed to a high dose of mating pheromone, the yeast cell undergoes growth arrest and forms a shmoo-like morphology; however, at intermediate doses, chemotropic elongated growth is initialized. To understand the gene regulatory networks that control this differentiation switch, we employed a high-throughput microfluidic imaging system that allows real-time and simultaneous measurements of cell growth and protein expression. Using kinetic modeling of protein dynamics, we classified the stimulus-dependent changes in protein abundance into two sources: global changes due to physiological alterations and gene-specific changes. A quantitative framework was proposed to decouple gene-specific regulatory modes from the growth-dependent global modulation of protein abundance. Based on the temporal patterns of gene-specific regulation, we established the network architectures underlying distinct cell fates using a reverse engineering method and uncovered the dose-dependent rewiring of gene regulatory network during mating differentiation. Furthermore, our results suggested a potential crosstalk between the pheromone response pathway and the target of rapamycin (TOR)-regulated ribosomal biogenesis pathway, which might underlie a cell differentiation switch in yeast mating response. In summary, our modeling approach addresses the distinct impacts of the global and gene-specific regulation on the control of protein dynamics and provides new insights into the mechanisms of cell fate determination. We anticipate that our

Influence the oxidant action of selenium in radiosensitivity induction and cell death in yeast Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Porto, Barbara Abranches de Araujo

2012-01-01

Ionizing radiations are from both natural sources such as from anthropogenic sources. Recently, radiotherapy has emerged as one of the most common therapies against cancer. Co-60 irradiators (cobalt-60 linear accelerators) are used to treat of malignant tumors routinely in hospitals around the world. Exposure to ionizing radiation can induce changes in cellular macromolecules and affect its functions, because they cause radiolysis of the water molecule generating reactive oxygen species, which can cause damage to virtually all organelles and cell components known as oxidative damage that can culminate in oxidative stress. Oxidative stress is a situation in which the balance between oxidants and antioxidants is broken resulting in excessive production of reactive species, it is not accompanied by the increase in antioxidant capacity, making it impossible to neutralize them. Selenium is a micronutrient considered as antioxidant, antiinflammatory, which could prevent cancer. Selenium in biological system exists as seleno proteins. Nowadays, 25 human seleno proteins have been identified, including glutathione peroxidase, an antioxidant enzyme. Yeasts have the ability to incorporate various metals such as iron, cadmium, zinc and selenium, as well as all biological organisms. The yeast Saccharomyces cerevisiae, unlike mammalian cells is devoid of seleno proteins, being considered as a practical model for studies on the toxicity of selenium, without any interference from the metabolism of seleno proteins. Moreover, yeast cells proliferate through the fermentation, the microbial equivalent of aerobic glycolysis in mammals and the process is also used by tumors. Several reports show that the pro-oxidante effects and induced toxic selenium compounds occur at lower doses and in malignant cells compared with benign cells. Therefore selenium giving a great therapeutic potential in cancer treatment .Our objective was to determine whether selenium is capable to sensitize yeasts

Effect of inactive yeast cell wall on growth performance, survival rate and immune parameters in Pacific White Shrimp (Litopenaeus vannamei

Directory of Open Access Journals (Sweden)

Rutchanee Chotikachinda

2008-10-01

Full Text Available Effects of dietary inactive yeast cell wall on growth performance, survival rate, and immune parameters in pacific white shrimp (Litopenaeus vannamei was investigated. Three dosages of inactive yeast cell wall (0, 1, and 2 g kg-1 were tested in three replicate groups of juvenile shrimps with an average initial weight of 7.15±0.05 g for four weeks. There was no significant difference in final weight, survival rate, specific growth rate, feed conversion ratio, feed intake, protein efficiency ratio, and apparent net protein utilization of each treatments. However, different levels of inactive yeast cell wall showed an effect on certain immune parameters (p<0.05. Total hemocyte counts, granular hemocyte count, and bacterial clearance were better in shrimp fed diets supplemented with 1 and 2 g kg-1 inactive yeast cell wall as compared with thecontrol group.

Yeast tRNAPhe expressed in human cells can be selected by HIV-1 for use as a reverse transcription primer

International Nuclear Information System (INIS)

Kelly, Nathan J.; Morrow, Casey D.

2003-01-01

All naturally occurring human immune deficiency viruses (HIV-1) select and use tRNA Lys,3 as the primer for reverse transcription. Studies to elucidate the mechanism of tRNA selection from the intracellular milieu have been hampered due to the difficulties in manipulating the endogenous levels of tRNA Lys,3 . We have previously described a mutant HIV-1 with a primer binding site (PBS) complementary to yeast tRNA Phe (psHIV-Phe) that relies on transfection of yeast tRNA Phe for infectivity. To more accurately recapitulate the selection process, a cDNA was designed for the intracellular expression of the yeast tRNA Phe . Increasing amounts of the plasmid encoding tRNA Phe resulted in a corresponding increase in levels of yeast tRNA Phe in the cell. The yeast tRNA Phe isolated from cells transfected with the cDNA for yeast tRNA Phe , or in the cell lines expressing yeast tRNA Phe , were aminoacylated, indicating that the expressed yeast tRNA Phe was incorporated into tRNA biogenesis pathways and translation. Increasing the cytoplasmic levels of tRNA Phe resulted in increased encapsidation of tRNA Phe in viruses with a PBS complementary to tRNA Phe (psHIV-Phe) or tRNA Lys,3 (wild-type HIV-1). Production of infectious psHIV-Phe was dependent on the amount of cotransfected tRNA Phe cDNA. Increasing amounts of plasmids encoding yeast tRNA Phe produced an increase of infectious psHIV-Phe that plateaued at a level lower than that from the transfection of the wild-type genome, which uses tRNA Lys,3 as the primer for reverse transcription. Cell lines were generated that expressed yeast tRNA Phe at levels approximately 0.1% of that for tRNA Lys,3 . Even with this reduced level of yeast tRNA Phe , the cell lines complemented psHIV-Phe over background levels. The results of these studies demonstrate that intracellular levels of primer tRNA can have a direct effect on HIV-1 infectivity and further support the role for PBS-tRNA complementarity in the primer selection process

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

Science.gov (United States)

Johann, Susana; Sá, Nívea P; Lima, Luciana A R S; Cisalpino, Patricia S; Cota, Betania B; Alves, Tânia M A; Siqueira, Ezequias P; Zani, Carlos L

2010-10-12

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. The hexane and dichlomethane fractions from leaves and stems of S. terebinthifolius were fractionated using several chromatography techniques to afford four compounds. 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 μg/ml. The isolate Pb 1578 was more sensitive to compound 1 with a MIC value of 7.5 μg/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. 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.

Interação de Paracoccidioides brasiliensis com células endoteliais

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M. J.S. Mendes-Giannini

2009-01-01

Full Text Available

A paracoccidioidomicose apresenta um amplo espectro de manifestações clínicas e Paracoccidioides brasiliensis, seu agente etiológico, pode atingir vários tecidos com ênfase ao pulmão. A migração de fungos patogênicos através da camada de células endoteliais é considerada pré-requisito para a invasão de múltiplos órgãos e sua disseminação. No presente estudo verificou-se a adesão de P. brasiliensis às células endoteliais in vitro e se esta adesão poderia representar um mecanismo para a disseminação do fungo. Para tanto, além da técnica convencional de microscopia ótica, uma outra metodologia foi desenvolvida, emblocando os cordões umbilicais em parafina, no intuito de detectar o fungo presente no material (in vivo. Experimento de migração de P. brasiliensis através da monocamada de células endoteliais também foi realizado, e nos poços sem células, a migração de células leveduriformes foi maior em menor período de tempo. Os fungos conseguiram passar através da monocamada, quando comparados com o controle sem as células, mas com redução em torno de 30%. Isso mostra que a monocamada foi parcialmente impediente para o fungo, mas que este foi capaz de migrar através dessas células. Em nossos experimentos com estas células, houve grande dificuldade de se encontrar P. brasiliensis aderido ao tapete celular nos períodos de tempo padronizados. Sugere-se com esses resultados que o fungo atravessa as células endoteliais de uma maneira muito rápida, que não pode ser detectada através do cultivo in vitro. Portanto, P. brasiliensis teria capacidade de atravessar rapidamente as células endoteliais e provavelmente alcançar tecidos mais profundos. Palavras-chave: Paracoccidioides brasiliensis, células endoteliais, migração.

In situ TLR2 and TLR4 expression in a murine model of mycetoma caused by Nocardia brasiliensis.

Science.gov (United States)

Millán-Chiu, Blanca Edith; Hernández-Hernández, Francisca; Pérez-Torres, Armando; Méndez-Tovar, Luis Javier; López-Martínez, Rubén

2011-04-01

Actinomycetoma caused by Nocardia brasiliensis is a common disease in tropical regions. This ailment is characterized by a localized chronic inflammation that mainly affects the lower limbs. Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns, inducing the production of proinflammatory mediators. The role of TLRs in the immune response against N. brasiliensis is unknown. The aim of this work was to locate and quantify in a murine model the expression of TLR2 and TLR4 in the infection site using reverse transcription-PCR and immunohistochemistry. The results showed that TLR2 expression increased in the infected tissue, whereas TLR4 expression decreased. The presence of TLR2 and TLR4 was demonstrated in different cell populations throughout the chronic infectious process. In the early stages of this process, TLR2 was expressed in neutrophils and macrophages in direct contact with the inoculum, whereas TLR4 was observed in mast cells. In the advanced stages of the infection, TLR2 was expressed in foam cells and fibroblasts and was likely associated with bacterial containment, while TLR4 was downregulated, probably resulting in an imbalance between the host immune response and the bacterial load that favoured chronic disease. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Evaluation of yeast single cell protein (SCP) diets on growth ...

African Journals Online (AJOL)

An investigation was carried out on the possibility of replacing fishmeal with graded levels of yeast single cell protein (SCP; 10, 20, 30, 40 and 50%) in isonitrogenous feed formulations (30% protein) in the diet of Oreochromis niloticus fingerlings for a period of 12 weeks. The control diet had fishmeal as the primary protein ...

Immunomodulatory effect of diethylcarbamazine in mice infected with Nocardia brasiliensis.

Science.gov (United States)

García-Hernández, M; Castro-Corona, M A; Segoviano-Ramírez, J C; Brattig, N W; Medina-De la Garza, C E

2014-11-01

We tested whether diethylcarbamazine (DEC) or ivermectin (IVM), both antiparasitic drugs with reported immunomodulatory properties, were able to affect the immune system to potentiate host defense mechanisms and protect against actinomycetoma in a mouse model. Male BALB/c mice of 10-12 weeks of age were injected with either Nocardia brasiliensis or saline solution. Recorded were the effects of a treatment by DEC (6 mg/kg per os daily for one week) or IVM (200 μg/kg subcutaneously on days 1 and 3) on (i) the development of mycetoma lesion, (ii) the expression of reactive oxygen intermediates (ROI) by phagocytes, (iii) the proliferation index of lymphocytes and (iv) antibody production of IgG and IgM. After an initial lesion in all mice, DEC inhibited a full development and progression of actinomycetoma resulting in a reduced lesion size (p brasiliensis antigens and concanavalin A in DEC-treated group was higher than in non-treated group at day 21 and 28 postinfection (p brasiliensis leading to retrogression of the mycetoma and increasing cellular immune responses. Our findings may indicate a potential use of DEC as a putative adjuvant in infectious disease or vaccination. Copyright © 2014 Elsevier B.V. All rights reserved.

Mercury bioaccumulation and elimination by Xenomelanires brasiliensis - radioactive tracers technique

International Nuclear Information System (INIS)

Malagrino, Waldir; Mesquita, Carlos Henrique de; Sousa, Eduinetty Ceci P.M. de

2002-01-01

The present work has as main objective to emphasized the importance of using radioactive tracers as well as to establish a methodology for the utilization of 203 Hg in the bioaccumulation study of mercury by X enomelanires brasiliensis. The exposure time was 168 hours. The bioaccumulation of mercury from the water as well as the elimination of the metal previously absorbed were determined by measuring the activity of 203 Hg, which was added to the water in the beginning of the experiments. The technique chosen is suitable to study the behavior of the stable mercury since the radioisotope used is an isotope of the same element and therefore presents the same chemical properties. The results obtained show that the absorption and elimination of mercury by Xenomelanires brasiliensis is slow, 168 hours being necessary for the elimination of 38 % of the previously absorbed mercury. The results are of main concern if it is considered that the literature about bioaccumulation of mercury by the Brazilian ichthyofauna is scarce. Furthermore the species Xenomelanires brasiliensis is part of the food chain and the results can be used in the evaluation of the potential risk of the mercury bioaccumulation by fishes of higher trophic levels and by men who are the final link of the food chain. (author)

Effect of NaCl and KCl on irradiated diploid yeast cells

International Nuclear Information System (INIS)

Amirtaev, K.G.; Lobachevskij, P.N.; Lyu Gvan Son

1984-01-01

Irradiated dipload yeast Saccharomyces cerevisiae kept in NaCl and KCl solutions died more readily than nonirradiated cells: the death rate was a functaon of radiation Jose and temperature of exposure. It was suggested that the radiation-induced injury to mass cell structures was responsible for the death rate. It was shown that the postirradiataon recovery of cells from radiation damages proceeded in KCl solution two-three times slower than mn water, and it was inhibited completely in NaCl solution

Evaluation of yeast cell wall on the performance of broiles fed diets with or without mycotoxins

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E Santin

2006-12-01

Full Text Available This experiment aimed at evaluating the effects of the interactions between aflatoxin (500 or 250 ppb and ochratoxin (500 or 250 ppb, and the possible benefits of adding yeast cell wall to prevent the effects of these mycotoxins in broiler chickens. Relative organ weight gain and live performance were evaluated at 21 and 42 days of age. Results indicated that at the levels of mycotoxins included in the experimental diets, ochratoxin reduced feed intake and body weight gain, and aflatoxin only affect feed intake of 21-day-old birds. No interaction was observed between aflatoxin and ochratoxin at the levels used in experimental study. Yeast cell wall did not significantly reduced the deleterious effects of ochratoxins. No significant differences were observed in relative organ weight gain. Yeast cell wall improved feed conversion ratio when birds were fed either contaminated or non-contaminated feeds.

Calorie Restriction-Mediated Replicative Lifespan Extension in Yeast Is Non-Cell Autonomous

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Mei, Szu-Chieh; Brenner, Charles

2015-01-01

In laboratory yeast strains with Sir2 and Fob1 function, wild-type NAD+ salvage is required for calorie restriction (CR) to extend replicative lifespan. CR does not significantly alter steady state levels of intracellular NAD+ metabolites. However, levels of Sir2 and Pnc1, two enzymes that sequentially convert NAD+ to nicotinic acid (NA), are up-regulated during CR. To test whether factors such as NA might be exported by glucose-restricted mother cells to survive later generations, we developed a replicative longevity paradigm in which mother cells are moved after 15 generations on defined media. The experiment reveals that CR mother cells lose the longevity benefit of CR when evacuated from their local environment to fresh CR media. Addition of NA or nicotinamide riboside (NR) allows a moved mother to maintain replicative longevity despite the move. Moreover, conditioned medium from CR-treated cells transmits the longevity benefit of CR to moved mother cells. Evidence suggests the existence of a longevity factor that is dialyzable but is neither NA nor NR, and indicates that Sir2 is not required for the longevity factor to be produced or to act. Data indicate that the benefit of glucose-restriction is transmitted from cell to cell in budding yeast, suggesting that glucose restriction may benefit neighboring cells and not only an individual cell. PMID:25633578

Calorie restriction-mediated replicative lifespan extension in yeast is non-cell autonomous.

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Szu-Chieh Mei

2015-01-01

Full Text Available In laboratory yeast strains with Sir2 and Fob1 function, wild-type NAD+ salvage is required for calorie restriction (CR to extend replicative lifespan. CR does not significantly alter steady state levels of intracellular NAD+ metabolites. However, levels of Sir2 and Pnc1, two enzymes that sequentially convert NAD+ to nicotinic acid (NA, are up-regulated during CR. To test whether factors such as NA might be exported by glucose-restricted mother cells to survive later generations, we developed a replicative longevity paradigm in which mother cells are moved after 15 generations on defined media. The experiment reveals that CR mother cells lose the longevity benefit of CR when evacuated from their local environment to fresh CR media. Addition of NA or nicotinamide riboside (NR allows a moved mother to maintain replicative longevity despite the move. Moreover, conditioned medium from CR-treated cells transmits the longevity benefit of CR to moved mother cells. Evidence suggests the existence of a longevity factor that is dialyzable but is neither NA nor NR, and indicates that Sir2 is not required for the longevity factor to be produced or to act. Data indicate that the benefit of glucose-restriction is transmitted from cell to cell in budding yeast, suggesting that glucose restriction may benefit neighboring cells and not only an individual cell.

Acrolein-Induced Oxidative Stress and Cell Death Exhibiting Features of Apoptosis in the Yeast Saccharomyces cerevisiae Deficient in SOD1.

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Kwolek-Mirek, Magdalena; Zadrąg-Tęcza, Renata; Bednarska, Sabina; Bartosz, Grzegorz

2015-04-01

The yeast Saccharomyces cerevisiae is a useful eukaryotic model to study the toxicity of acrolein, an important environmental toxin and endogenous product of lipid peroxidation. The study was aimed at elucidation of the cytotoxic effect of acrolein on the yeast deficient in SOD1, Cu, Zn-superoxide dismutase which is hypersensitive to aldehydes. Acrolein generated within the cell from its precursor allyl alcohol caused growth arrest and cell death of the yeast cells. The growth inhibition involved an increase in production of reactive oxygen species and high level of protein carbonylation. DNA condensation and fragmentation, exposition of phosphatidylserine at the cell surface as well as decreased dynamic of actin microfilaments and mitochondria disintegration point to the induction of apoptotic-type cell death besides necrotic cell death.

Inactivation of rifampin by Nocardia brasiliensis.

OpenAIRE

Yazawa, K; Mikami, Y; Maeda, A; Akao, M; Morisaki, N; Iwasaki, S

1993-01-01

Rifampin was glycosylated by a pathogenic species of Nocardia, i.e., Nocardia brasiliensis. The structures of two glycosylated compounds (RIP-1 and RIP-2) isolated from the culture broth of the bacterium were determined to be 3-formyl-23-(O-[beta-D-glucopyranosyl])rifamycin SV and 23-(O-[beta-D-glucopyranosyl])rifampin, respectively. Both compounds lacked antimicrobial activity against other gram-positive bacteria as well as the Nocardia species.

Micetoma por Nocardia brasiliensis: reporte de caso

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Miriam Guevara R

2003-07-01

Full Text Available Se presenta el caso de un paciente peruano, agricultor, con una infección cutánea de origen traumático causada por Nocardia brasiliensis, que evolucionó hacia la amputación del miembro inferior afectado. El diagnóstico se realizó por examen directo y cultivo del espécimen.

The duration of mitosis and daughter cell size are modulated by nutrients in budding yeast.

Science.gov (United States)

Leitao, Ricardo M; Kellogg, Douglas R

2017-11-06

The size of nearly all cells is modulated by nutrients. Thus, cells growing in poor nutrients can be nearly half the size of cells in rich nutrients. In budding yeast, cell size is thought to be controlled almost entirely by a mechanism that delays cell cycle entry until sufficient growth has occurred in G1 phase. Here, we show that most growth of a new daughter cell occurs in mitosis. When the rate of growth is slowed by poor nutrients, the duration of mitosis is increased, which suggests that cells compensate for slow growth in mitosis by increasing the duration of growth. The amount of growth required to complete mitosis is reduced in poor nutrients, leading to a large reduction in cell size. Together, these observations suggest that mechanisms that control the extent of growth in mitosis play a major role in cell size control in budding yeast. © 2017 Leitao and Kellogg.

Glyoxalase I expression pattern in Hevea brasiliensis seedlings ...

African Journals Online (AJOL)

Glyoxalase I expression pattern in Hevea brasiliensis seedlings under varied stress conditions. MVP Siraj, A Thulaseedharan, Anu Augustine. Abstract. Drought is one of the most important stress factors which adversely affect plants' growth and productivity. Global climate change may make this situation more serious in the ...

Long-term tracking of budding yeast cells in brightfield microscopy: CellStar and the Evaluation Platform.

Science.gov (United States)

Versari, Cristian; Stoma, Szymon; Batmanov, Kirill; Llamosi, Artémis; Mroz, Filip; Kaczmarek, Adam; Deyell, Matt; Lhoussaine, Cédric; Hersen, Pascal; Batt, Gregory

2017-02-01

With the continuous expansion of single cell biology, the observation of the behaviour of individual cells over extended durations and with high accuracy has become a problem of central importance. Surprisingly, even for yeast cells that have relatively regular shapes, no solution has been proposed that reaches the high quality required for long-term experiments for segmentation and tracking (S&T) based on brightfield images. Here, we present CellStar , a tool chain designed to achieve good performance in long-term experiments. The key features are the use of a new variant of parametrized active rays for segmentation, a neighbourhood-preserving criterion for tracking, and the use of an iterative approach that incrementally improves S&T quality. A graphical user interface enables manual corrections of S&T errors and their use for the automated correction of other, related errors and for parameter learning. We created a benchmark dataset with manually analysed images and compared CellStar with six other tools, showing its high performance, notably in long-term tracking. As a community effort, we set up a website, the Yeast Image Toolkit, with the benchmark and the Evaluation Platform to gather this and additional information provided by others. © 2017 The Authors.

Biologia floral e visitantes de Gaylussacia brasiliensis (Spr. Meissner (Ericaceae - uma espécie com anteras poricidas polinizada por beija-flores Floral biology and visitors of Gaylussacia brasiliensis (Spr. Meissner (Ericaceae - a poricidal anther species pollinated by hummingbirds

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Francielle Paulina de Araújo

2011-06-01

Full Text Available A biologia floral de Gaylussacia brasiliensis (Spr. Meissner (Ericaceae foi estudada na borda de uma mata de galeria na reserva ecológica do Clube de Caça e Pesca Itororó de Uberlândia, Minas Gerais. G. brasiliensis é um arbusto que pode alcançar de 0,3 a 3,0 m de altura e ocorre de forma isolada ou agregada. Apresenta floração contínua e possui inflorescências racemosas, axilares com flores pendentes. As flores são hermafroditas, vermelhas, de corola urceolada, apresentam antese diurna e ausência odor. O néctar apresentou volume de cerca de 3,0 μL e concentração de açúcares por volta de 13%. G. brasiliensis é autocompatível, não apresenta autopolinização espontânea e nem apomixia. Os polinizadores foram os beijaflores: Chlorostlibon lucidus (Shaw, Amazilia fimbirata (Gmelin, Hylocharis chrysura (Shaw (Throchilinae e Phaethornis pretrei (Lesson & DeLattre (Phaethornithinae. G. brasiliensis apresenta anteras poricidas com poros amplos e os beija-flores, quando adejam com o bico inserido nas flores em busca de néctar, fornecem a vibração necessária para a liberação dos grãos de pólen. Apesar de apresentar volume e concentração de açúcar no néctar relativamente pequenos, os agrupamentos de indivíduos com muitas flores parecem atrair beija-flores com comportamento territorial.The floral biology of Gaylussacia brasiliensis (Spr. Meissner (Ericaceae was studied on swampy edges of a gallery forest in Uberlandia, Minas Gerais. Gaylussacia brasiliensis is a shrub 0.3 to 3.0 m tall that occurs isolated or aggregated and has continuous flowering. The axillary racemose inflorescences produce four to dozens of pendulous flowers. The flowers are hermaphroditic, red, urceolate, odorless and have diurnal anthesis. Concentration of sugars in nectar was c. 13% and volume c. 3.0 μL. G. brasiliensis is a self-compatible, non apomictic species, which does not present spontaneous self-pollination. The pollinators of G

Yeasts preservation: alternatives for lyophilisation

OpenAIRE

Nyanga, Loveness K.; Nout, Martinus J. R.; Smid, Eddy J.; Boekhout, Teun; Zwietering, Marcel H.

2012-01-01

The aim of the study was to compare the effect of two low-cost, low technology traditional methods for drying starter cultures with standard lyophilisation. Lyophilised yeast cultures and yeast cultures preserved in dry rice cakes and dry plant fibre strands were examined for viable cell counts during 6 months storage at 4 and 25 °C. None of the yeast cultures showed a significant loss in viable cell count during 6 months of storage at 4 °C upon lyophilisation and preservation in dry rice cak...

Regulatory mechanism of the flavoprotein Tah18-dependent nitric oxide synthesis and cell death in yeast.

Science.gov (United States)

Yoshikawa, Yuki; Nasuno, Ryo; Kawahara, Nobuhiro; Nishimura, Akira; Watanabe, Daisuke; Takagi, Hiroshi

2016-07-01

Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. The regulatory mechanism of NO generation in unicellular eukaryotic yeast cells is poorly understood due to the lack of mammalian and bacterial NO synthase (NOS) orthologues, even though yeast produces NO under oxidative stress conditions. Recently, we reported that the flavoprotein Tah18, which was previously shown to transfer electrons to the iron-sulfur cluster protein Dre2, is involved in NOS-like activity in the yeast Saccharomyces cerevisiae. On the other hand, Tah18 was reported to promote apoptotic cell death after exposure to hydrogen peroxide (H2O2). Here, we showed that NOS-like activity requiring Tah18 induced cell death upon treatment with H2O2. Our experimental results also indicate that Tah18-dependent NO production and cell death are suppressed by enhancement of the interaction between Tah18 and its molecular partner Dre2. Our findings indicate that the Tah18-Dre2 complex regulates cell death as a molecular switch via Tah18-dependent NOS-like activity in response to environmental changes. Copyright © 2016 Elsevier Inc. All rights reserved.

Draft genome sequence of the rubber tree Hevea brasiliensis

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Rahman Ahmad Yamin Abdul

2013-02-01

Full Text Available Abstract 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.

Detecting estrogenic activity in water samples withestrogen-sensitive yeast cells using spectrophotometry and fluorescencemicroscopy

Energy Technology Data Exchange (ETDEWEB)

Wozei, E.; Holman, H-Y.N.; Hermanowicz, S.W.; Borglin S.

2006-03-15

Environmental estrogens are environmental contaminants that can mimic the biological activities of the female hormone estrogen in the endocrine system, i.e. they act as endocrine disrupters. Several substances are reported to have estrogen-like activity or estrogenic activity. These include steroid hormones, synthetic estrogens (xenoestrogens), environmental pollutants and phytoestrogens (plant estrogens). Using the chromogenic substrate ortho-nitrophenyl-{beta}-D-galactopyranoside (ONPG) we show that an estrogen-sensitive yeast strain RMY/ER-ERE, with human estrogen receptor (hER{alpha}) gene and the lacZ gene which encodes the enzyme {beta}-galactosidase, is able to detect estrogenic activity in water samples over a wide range of spiked concentrations of the hormonal estrogen 17{beta}-estradiol (E2). Ortho-nitrophenol (ONP), the yellow product of this assay can be detected using spectrophotometry but requires cell lysis to release the enzyme and allow product formation. We improved this aspect in a fluorogenic assay by using fluorescein di-{beta}-D-galactopyranoside (FDG) as a substrate. The product was visualized using fluorescence microscopy without the need to kill, fix or lyse the cells. We show that in live yeast cells, the uptake of E2 and the subsequent production of {beta}-galactosidase enzyme occur quite rapidly, with maximum enzyme-catalyzed fluorescent product formation evident after about 30 minutes of exposure to E2. The fluorogenic assay was applied to a selection of estrogenic compounds and the Synchrotron-based Fourier transform infrared (SR-FTIR) spectra of the cells obtained to better understand the yeast whole cell response to the compounds. The fluorogenic assay is most sensitive to E2, but the SR-FTIR spectra suggest that the cells respond to all the estrogenic compounds tested even when no fluorescent response was detected. These findings are promising and may shorten the duration of environmental water screening and monitoring regimes using

The small GTPase Rab5 homologue Ypt5 regulates cell morphology, sexual development, ion-stress response and vacuolar formation in fission yeast

Energy Technology Data Exchange (ETDEWEB)

Tsukamoto, Yuta; Katayama, Chisako [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan); Shinohara, Miki; Shinohara, Akira [Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Maekawa, Shohei [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan); Miyamoto, Masaaki, E-mail: miya@kobe-u.ac.jp [Graduate School of Science, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan); Center for Supports to Research and Education Activities, Kobe University, 1-1 Rokkodai-cho Nada, Kobe 657-8501 (Japan)

2013-11-29

Highlights: •Multiple functions of Rab5 GTPase in fission yeast were found. •Roles of Rab5 in fission yeast were discussed. •Relation between Rab5 and actin cytoskeleton were discussed. -- Abstract: Inner-membrane transport is critical to cell function. Rab family GTPases play an important role in vesicle transport. In mammalian cells, Rab5 is reported to be involved in the regulation of endosome formation, phagocytosis and chromosome alignment. Here, we examined the role of the fission yeast Rab5 homologue Ypt5 using a point mutant allele. Mutant cells displayed abnormal cell morphology, mating, sporulation, endocytosis, vacuole fusion and responses to ion stress. Our data strongly suggest that fission yeast Rab5 is involved in the regulation of various types of cellular functions.

The small GTPase Rab5 homologue Ypt5 regulates cell morphology, sexual development, ion-stress response and vacuolar formation in fission yeast

International Nuclear Information System (INIS)

Tsukamoto, Yuta; Katayama, Chisako; Shinohara, Miki; Shinohara, Akira; Maekawa, Shohei; Miyamoto, Masaaki

2013-01-01

Highlights: •Multiple functions of Rab5 GTPase in fission yeast were found. •Roles of Rab5 in fission yeast were discussed. •Relation between Rab5 and actin cytoskeleton were discussed. -- Abstract: Inner-membrane transport is critical to cell function. Rab family GTPases play an important role in vesicle transport. In mammalian cells, Rab5 is reported to be involved in the regulation of endosome formation, phagocytosis and chromosome alignment. Here, we examined the role of the fission yeast Rab5 homologue Ypt5 using a point mutant allele. Mutant cells displayed abnormal cell morphology, mating, sporulation, endocytosis, vacuole fusion and responses to ion stress. Our data strongly suggest that fission yeast Rab5 is involved in the regulation of various types of cellular functions

Increase of ethanol productivity by cell-recycle fermentation of flocculating yeast.

Science.gov (United States)

Wang, F Z; Xie, T; Hui, M

2011-01-01

Using the recombinant flocculating Angel yeast F6, long-term repeated batch fermentation for ethanol production was performed and a high volumetric productivity resulted from half cells not washed and the optimum opportunity of residual glucose 20 g l(-1) of last medium. The obtained highest productivity was 2.07 g l-(1) h(-1), which was improved by 75.4% compared with that of 1.18 g l(-1) h(-1) in the first batch fermentation. The ethanol concentration reached 8.4% corresponding to the yield of 0.46 g g(-1). These results will contribute greatly to the industrial production of fuel ethanol using the commercial method with the flocculating yeast.

A fatal pulmonary infection by Nocardia brasiliensis.

Science.gov (United States)

Wadhwa, V; Rai, S; Kharbanda, P; Kabra, S; Gur, R; Sharma, V K

2006-01-01

The reported case is of primary pulmonary nocardiosis, caused by Nocardia brasiliensis, in a immunocompromised patient, which ended fatally despite appropriate treatment. The partially acid fast filamentous bacterium was predominant on direct examination of the sputum. It was cultured on blood agar, MacConkey agar and by paraffin baiting technique. The bacterium was resistant to cotrimoxazole, the drug of choice for nocardiosis.

Study on the specificity of yeast cell damage by high-intensity UV radiation (266nm)

International Nuclear Information System (INIS)

Burchuladze, T.G.; Frajkin, G.Ya.; Rubin, L.B.

1981-01-01

Peculiarities of photoreactivation and photoprotection of the Candida guilliermondii and Candida utilis yeast cells, irradiated with far and near ultraviolet radiation, are considered. New results on the study of the dependence of the cells inactivation degree on the intensity of ultraviolet radiation are presented. The impulse rate density at 266 nm reached 10 10 Ix m -2 xs -1 at the impulse duration of 10 -8 s. Survival curves of the yeast cells during their irradiation with ultraviolet radiation of 266 nm and 254 nm are given. It is shown that with the increase of the irradiation intensity of 266 nm the rates and final levels of photoreactivation decrease. Under the effect of ultraviolet irradiation of high intensity contribution of pyrimidine dimers to the cell inactivation decreases [ru

ODE, RDE and SDE models of cell cycle dynamics and clustering in yeast.

Science.gov (United States)

Boczko, Erik M; Gedeon, Tomas; Stowers, Chris C; Young, Todd R

2010-07-01

Biologists have long observed periodic-like oxygen consumption oscillations in yeast populations under certain conditions, and several unsatisfactory explanations for this phenomenon have been proposed. These ‘autonomous oscillations’ have often appeared with periods that are nearly integer divisors of the calculated doubling time of the culture. We hypothesize that these oscillations could be caused by a form of cell cycle synchronization that we call clustering. We develop some novel ordinary differential equation models of the cell cycle. For these models, and for random and stochastic perturbations, we give both rigorous proofs and simulations showing that both positive and negative growth rate feedback within the cell cycle are possible agents that can cause clustering of populations within the cell cycle. It occurs for a variety of models and for a broad selection of parameter values. These results suggest that the clustering phenomenon is robust and is likely to be observed in nature. Since there are necessarily an integer number of clusters, clustering would lead to periodic-like behaviour with periods that are nearly integer divisors of the period of the cell cycle. Related experiments have shown conclusively that cell cycle clustering occurs in some oscillating yeast cultures.

Inmunoglobulinas en pacientes con actinomicetoma por Nocardia brasiliensis Immunoglobulins in patients with Nocardia brasiliensis actinomycetoma

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L. J. Méndez-Tovar

2004-12-01

Full Text Available Considerando que algunos autores han reportado un aumento en la cantidad de algunas inmunoglobulinas en los pacientes con actinomicetoma, en este trabajo nos propusimos determinar diferencias en la producción de IgG1, IgG2, IgG3, IgG4 e IgM en 25 pacientes con actinomicetoma por Nocardia brasiliensis y 25 personas sanas provenientes de una zona endémica de micetoma. La determinación de inmunoglobulinas se realizó por medio de la técnica de ELISA. Para sensibilizar las placas se emplearon 6 antígenos de N. brasiliensis: un antígeno crudo denominado NB y cinco derivados del mismo (NB2, NB4, NB6, NB8 y NB10 separados por punto isoeléctrico. Los niveles de las cuatro subclases de IgG fueron mayores en los sueros de los pacientes que en el suero de los controles, con una diferencia máxima en IgG3 e IgG4; para esta última subclase, los seis antígenos fueron altamente reactivos. La concentración de IgM fue igual en ambos grupos. Es probable que como ocurre en otras infecciones, en la fisiopatogenia del actinomicetoma influya no sólo el aumento o deficiencia de una clase de inmunoglobulina, sino la relación que existe entre las diferentes subclases.Considering that some authors have reported an increasing of some immunoglobulins in actinomycetoma patients, in this study we propose to determine differential production of IgG1, IgG2, IgG3, IgG4 and IgGM in 25 patients with actinomycetoma and 25 healthy individuals from a mycetoma endemic area. Immunoglobulins were determined by ELISA technique. To sensibilize the plates, six Nocardia brasiliensis antigens were used: a crude antigen denominated NB and five derivatives (NB2, NB4, NB6, NB8 and NB10 obtained by their isoelectric point. Results showed that all IgG subclasses were higher in the patients’ sera than in control sera, with a maximal difference to IgG3 and IgG4. To the latter subclass, six antigens were highly reactives. IgM levels were similar in both groups. As it occurs in other

The indentation of pressurized elastic shells: from polymeric capsules to yeast cells

KAUST Repository

Vella, D.; Ajdari, A.; Vaziri, A.; Boudaoud, A.

2011-01-01

of capsules. Our results are relevant for determining the internal pressure in bacterial, fungal or plant cells. As an illustration of this, we apply our results to recent measurements of the stiffness of baker's yeast and infer from these experiments

Actinomycetoma in arm disseminated to lung with grains of Nocardia brasiliensis with peripheral filaments.

Science.gov (United States)

Muñoz-Hernández, Bertha; Noyola, María Cecilia; Palma-Cortés, Gabriel; Rosete, Dora Patricia; Galván, Miguel Angel; Manjarrez, María Eugenia

2009-07-01

Actinomycetomas represent 97.8% of mycetomas in Mexico, where 86.6% are produced by Nocardia brasiliensis. We report a case of actinomycetoma in the arm by Nocardia brasiliensis disseminated to lung. Uncommon grains were observed which present outside peripheral filaments and also numerous filaments loosing the grains. These characteristics of the grains are due probably because for the long treatment with antibiotics of the patient. In situ antibiotic action against the microcolonies is discussed.

Fatty acids from oleaginous yeasts and yeast-like fungi and their potential applications.

Science.gov (United States)

Xue, Si-Jia; Chi, Zhe; Zhang, Yu; Li, Yan-Feng; Liu, Guang-Lei; Jiang, Hong; Hu, Zhong; Chi, Zhen-Ming

2018-02-01

Oleaginous yeasts, fatty acids biosynthesis and regulation in the oleaginous yeasts and the fatty acids from the oleaginous yeasts and their applications are reviewed in this article. Oleaginous yeasts such as Rhodosporidium toruloides, Yarrowia lipolytica, Rhodotorula mucilaginosa, and Aureobasidium melanogenum, which can accumulate over 50% lipid of their cell dry weight, have many advantages over other oleaginous microorganisms. The fatty acids from the oleaginous yeasts have many potential applications. Many oleaginous yeasts have now been genetically modified to over-produce fatty acids and their derivatives. The most important features of the oleaginous yeasts are that they have special enzymatic systems for enhanced biosynthesis and regulation of fatty acids in their lipid particles. Recently, some oleaginous yeasts such as R. toruloides have been found to have a unique fatty acids synthetase and other oleaginous yeasts such as A. melanogenum have a unique highly reducing polyketide synthase (HR-PKS) involved in the biosynthesis of hydroxyl fatty acids. It is necessary to further enhance lipid biosynthesis using metabolic engineering and explore new applications of fatty acids in biotechnology.

Synergetic effect of yeast cell-surface expression of cellulase and expansin-like protein on direct ethanol production from cellulose

Science.gov (United States)

2013-01-01

Background Numerous studies have examined the direct fermentation of cellulosic materials by cellulase-expressing yeast; however, ethanol productivity in these systems has not yet reached an industrial level. Certain microorganisms, such as the cellulolytic fungus Trichoderma reesei, produce expansin-like proteins, which have a cellulose-loosening effect that may increase the breakdown of cellulose. Here, to improve the direct conversion of cellulose to ethanol, yeast Saccharomyces cerevisiae co-displaying cellulase and expansin-like protein on the cell surface were constructed and examined for direct ethanol fermentation performance. Results The cellulase and expansin-like protein co-expressing strain showed 246 mU/g-wet cell of phosphoric acid swollen cellulose (PASC) degradation activity, which corresponded to 2.9-fold higher activity than that of a cellulase-expressing strain. This result clearly demonstrated that yeast cell-surface expressed cellulase and expansin-like protein act synergistically to breakdown cellulose. In fermentation experiments examining direct ethanol production from PASC, the cellulase and expansin-like protein co-expressing strain produced 3.4 g/L ethanol after 96 h of fermentation, a concentration that was 1.4-fold higher than that achieved by the cellulase-expressing strain (2.5 g/L). Conclusions The PASC degradation and fermentation ability of an engineered yeast strain was markedly improved by co-expressing cellulase and expansin-like protein on the cell surface. To our knowledge, this is the first report to demonstrate the synergetic effect of co-expressing cellulase and expansin-like protein on a yeast cell surface, which may be a promising strategy for constructing direct ethanol fermenting yeast from cellulose. PMID:23835302

Teste de especificidade hospedeira de Phaedon confinis (Coleoptera, Chrysomelidae, um potencial agente de biocontrole de Senecio brasiliensis (Asteraceae.

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Julianne Milléo

2011-07-01

Abstract. Senecio brasiliensis (Spreng. Less when ingested by cattle and horses, the plant causes seneciosis, a serious poisoning. Due to the great financial losses to cattle ranchers, controlling the plant using insects has become attractive. Systematic survey efforts have revealed that Phaedon confinis Klug causes serious damage to the plant, and may be a great biocontrol agent. The object was to extend the tests of host specificity to 52 plants using 1st larval instar and adult chrysomelid bettles. The insects were submitted to “no-choice” and “multiple-choice” tests. The following results were obtained: “NO-CHOICE” L1 – 52 plants tested: null 90.39%; negligible damage 5.77%; light 1.92%; and normal in only S. brasiliensis 1.92%, where 31.67% of larvae obtained an adult phase. “NO-CHOICE” ADULTS – 46 plants. Null damage was recorded in 82.60%; 13.04% showed negligible damage; 2.17% light; 2.17% normal in S. brasiliensis. The chysomelids oviposited during observation days only on S. brasiliensis leaves. 615 eggs were oviposited with 73.01% viability. “MULTIPLE CHOICE” LARVAE – nine plants tested. 66.67% null; 11.11% weak; 11.11% negligible damage; and 11.11% normal in S. brasiliensis. The results indicate that the normal diet, oviposition, survival and development of P. confinis is restricted to S. brasiliensis and corroborates its potential as a biocontrol agent.

Protein patterns of yeast during sporulation

International Nuclear Information System (INIS)

Litske Petersen, J.G.; Kielland-Brandt, M.C.; Nilsson-Tillgren, T.

1979-01-01

High resolution two-dimensional gel electrophoresis was used to study protein synthesis during synchronous meiosis and ascospore formation of Saccharomyces cerevisiae. The stained protein patterns of samples harvested at any stage between meiotic prophase and the four-spore stage in two sporulating strains showed the same approximately 250 polypeptides. Of these only a few seemed to increase or decrease in concentration during sporulation. The characteristic pattern of sporulating yeast was identical to the pattern of glucose-grown staitonary yeast cells adapted to respiration. The latter type of cells readily initiates meiosis when transferred to sporulation medium. This pattern differed from the protein patterns of exponentially growing cells in glucose or acetate presporulation medium. Five major proteins in stationary and sporulating yeast cells were not detected in either type of exponential culture. Two-dimensional autoradiograms of [ 35 S]methionine-labelled yeast proteins revealed that some proteins were preferentially labelled during sporulation, while other proteins were labelled at later stages. These patterns differed from the auroradiograms of exponentially growing yeast cells in glucose presporulation medium in a number of spots. No differences were observed when stained gels or autoradiograms of sporulating cultures and non-sporulating strains in sporulation medium were compared. (author)

Triterpenoid saponins from Tocoyena brasiliensis Mart. (Rubiaceae); Saponinas triterpenicas de Tocoyena brasiliensis Mart. (Rubiaceae)

Energy Technology Data Exchange (ETDEWEB)

Hamerski, Lidilhone; Carbomezi, Carlos Alberto; Cavalheiro, Alberto Jose; Bolzani, Vanderlan da Silva [UNESP, Araraquara, SP (Brazil). Inst. de Quimica]. E-mail: bolzaniv@iq.unesp.br; Young, Maria Claudia Marx [Instituto de Botanica, Sao Paulo, SP (Brazil). Secao de Fisiologia e Bioquimica de Plantas

2005-07-15

The present communication reports the isolation and identification of four triterpenoid saponins from the chloroform extract of the leaves of Tocoyena brasiliensis: 3-O-{beta}-D quinovopyranosyl quinovic acid, 3-O-{beta}-D-quinovopyranosyl cincholic acid, 3-O-{beta}-D-glucopyranosyl quinovic acid and the 28-O-{beta}-D-glucopyranosyl ester derivative of quinovic acid as binary mixtures, respectively. From the ethanol extract a flavonoid identified as ramnazin-3-O-rutinoside was obtained. The structures of these compounds were assigned by data analysis of 1D and 2D NMR spectrometry and comparison with data recorded in the literature for these compounds. (author)

In Vivo Activity of the Benzothiazinones PBTZ169 and BTZ043 against Nocardia brasiliensis.

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Norma Alejandra González-Martínez

Full Text Available Mycetoma is a neglected, chronic, and deforming infectious disease caused by fungi and actinomycetes. In Mexico, N. brasiliensis is the predominant etiologic agent. Therapeutic alternatives are necessary because the current drug regimens have several disadvantages. Benzothiazinones (BTZ are a new class of candidate drugs that inhibit decaprenyl-phosphoribose-epimerase (DprE1, an essential enzyme involved in the cell wall biosynthesis of Corynebacterineae.In this study, the in vitro activity of the next generation BTZ, PBTZ169, was tested against thirty Nocardia brasiliensis isolates. The MIC50 and MIC90 values for PBTZ169 were 0.0075 and 0.03 μg/mL, respectively. Because Nocardia is a potential intracellular bacterium, a THP-1 macrophage monolayer was infected with N. brasiliensis HUJEG-1 and then treated with PBTZ169, resulting in a decrease in the number of colony-forming units (CFUs at a concentration of 0.25X the in vitro value. The in vivo activity was evaluated after infecting female BALB/c mice in the right hind food-pad. After 6 weeks, treatment was initiated with PBTZ169 and its activity was compared with the first generation compound, BTZ043. Both BTZ compounds were administered at 100 mg/kg twice daily by gavage, and sulfamethoxazole/trimethoprim (SXT, at 100 mg/kg sulfamethoxazole, was used as a positive control. After 22 weeks of therapy, only PBTZ169 and SXT displayed statistically significant activity.These results indicate that DprE1 inhibitors may be useful for treating infections of Nocardia and may therefore be active against other actinomycetoma agents. We must test combinations of these compounds with other antimicrobial agents, such as linezolid, tedizolid or SXT, that have good to excellent in vivo activity, as well as new DprE1 inhibitors that can achieve higher plasma levels.

In Vivo Activity of the Benzothiazinones PBTZ169 and BTZ043 against Nocardia brasiliensis.

Science.gov (United States)

González-Martínez, Norma Alejandra; Lozano-Garza, Hector Gerardo; Castro-Garza, Jorge; De Osio-Cortez, Alexandra; Vargas-Villarreal, Javier; Cavazos-Rocha, Norma; Ocampo-Candiani, Jorge; Makarov, Vadim; Cole, Stewart T; Vera-Cabrera, Lucio

2015-01-01

Mycetoma is a neglected, chronic, and deforming infectious disease caused by fungi and actinomycetes. In Mexico, N. brasiliensis is the predominant etiologic agent. Therapeutic alternatives are necessary because the current drug regimens have several disadvantages. Benzothiazinones (BTZ) are a new class of candidate drugs that inhibit decaprenyl-phosphoribose-epimerase (DprE1), an essential enzyme involved in the cell wall biosynthesis of Corynebacterineae. In this study, the in vitro activity of the next generation BTZ, PBTZ169, was tested against thirty Nocardia brasiliensis isolates. The MIC50 and MIC90 values for PBTZ169 were 0.0075 and 0.03 μg/mL, respectively. Because Nocardia is a potential intracellular bacterium, a THP-1 macrophage monolayer was infected with N. brasiliensis HUJEG-1 and then treated with PBTZ169, resulting in a decrease in the number of colony-forming units (CFUs) at a concentration of 0.25X the in vitro value. The in vivo activity was evaluated after infecting female BALB/c mice in the right hind food-pad. After 6 weeks, treatment was initiated with PBTZ169 and its activity was compared with the first generation compound, BTZ043. Both BTZ compounds were administered at 100 mg/kg twice daily by gavage, and sulfamethoxazole/trimethoprim (SXT), at 100 mg/kg sulfamethoxazole, was used as a positive control. After 22 weeks of therapy, only PBTZ169 and SXT displayed statistically significant activity. These results indicate that DprE1 inhibitors may be useful for treating infections of Nocardia and may therefore be active against other actinomycetoma agents. We must test combinations of these compounds with other antimicrobial agents, such as linezolid, tedizolid or SXT, that have good to excellent in vivo activity, as well as new DprE1 inhibitors that can achieve higher plasma levels.

Beyond bread and beer: whole cell protein extracts from baker's yeast as a bulk source for 3D cell culture matrices.

Science.gov (United States)

Bodenberger, Nicholas; Kubiczek, Dennis; Paul, Patrick; Preising, Nico; Weber, Lukas; Bosch, Ramona; Hausmann, Rudolf; Gottschalk, Kay-Eberhard; Rosenau, Frank

2017-03-01

Here, we present a novel approach to form hydrogels from yeast whole cell protein. Countless hydrogels are available for sophisticated research, but their fabrication is often difficult to reproduce, with the gels being complicated to handle or simply too expensive. The yeast hydrogels presented here are polymerized using a four-armed, amine reactive crosslinker and show a high chemical and thermal resistance. The free water content was determined by measuring swelling ratios for different protein concentrations, and in a freeze-drying approach, pore sizes of up to 100 μm in the gel could be created without destabilizing the 3D network. Elasticity was proofed to be adjustable with the help of atomic force microscopy by merely changing the amount of used protein. Furthermore, the material was tested for possible cell culture applications; diffusion rates in the network are high enough for sufficient supply of human breast cancer cells and adenocarcinomic human alveolar basal epithelial cells with nutrition, and cells showed high viabilities when tested for compatibility with the material. Furthermore, hydrogels could be functionalized with RGD peptide and the optimal concentration for sufficient cell adhesion was determined to be 150 μM. Given that yeast protein is one of the cheapest and easiest available protein sources and that hydrogels are extremely easy to handle, the developed material has highly promising potential for both sophisticated cell culture techniques as well as for larger scale industrial applications.

A sphingolipid-dependent diffusion barrier confines ER stress to the yeast mother cell

Science.gov (United States)

Clay, Lori; Caudron, Fabrice; Denoth-Lippuner, Annina; Boettcher, Barbara; Buvelot Frei, Stéphanie; Snapp, Erik Lee; Barral, Yves

2014-01-01

In many cell types, lateral diffusion barriers compartmentalize the plasma membrane and, at least in budding yeast, the endoplasmic reticulum (ER). However, the molecular nature of these barriers, their mode of action and their cellular functions are unclear. Here, we show that misfolded proteins of the ER remain confined into the mother compartment of budding yeast cells. Confinement required the formation of a lateral diffusion barrier in the form of a distinct domain of the ER-membrane at the bud neck, in a septin-, Bud1 GTPase- and sphingolipid-dependent manner. The sphingolipids, but not Bud1, also contributed to barrier formation in the outer membrane of the dividing nucleus. Barrier-dependent confinement of ER stress into the mother cell promoted aging. Together, our data clarify the physical nature of lateral diffusion barriers in the ER and establish the role of such barriers in the asymmetric segregation of proteotoxic misfolded proteins during cell division and aging. DOI: http://dx.doi.org/10.7554/eLife.01883.001 PMID:24843009

Genetic and proteomic evidences support the localization of yeast enolase in the cell surface

DEFF Research Database (Denmark)

López-Villar, Elena; Monteoliva, Lucía; Larsen, Martin Røssel

2006-01-01

Although enolase, other glycolytic enzymes, and a variety of cytoplasmic proteins lacking an N-terminal secretion signal have been widely described as located at the cell surface in yeast and in mammalian cells, their presence in this external location is still controversial. Here, we report that...

Nocardia brasiliensis Infection Complicating Cryptogenic Organizing Pneumonia.

Science.gov (United States)

Fernandes, Alison M; Sluzevich, Jason C; Mira-Avendano, Isabel

2017-01-01

Pulmonary nocardiosis is a severe and uncommon opportunistic infection caused by Nocardia species. We present a patient with cryptogenic organizing pneumonia who was receiving long-term immunosuppressive therapy, whose treatment course was complicated by cutaneous and pulmonary nocardiosis. Tissue cultures confirmed Nocardia brasiliensis . Nocardiosis should be a diagnostic consideration for patients treated with long-term immunosuppression who have worsening pulmonary symptoms and relapsing pustular skin lesions.

A fatal pulmonary infection by Nocardia brasiliensis

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Wadhwa V

2006-01-01

Full Text Available The reported case is of primary pulmonary nocardiosis, caused by Nocardia brasiliensis , in a immunocompromised patient, which ended fatally despite appropriate treatment. The partially acid fast filamentous bacterium was predominant on direct examination of the sputum. It was cultured on blood agar, MacConkey agar and by paraffin baiting technique. The bacterium was resistant to cotrimoxazole, the drug of choice for nocardiosis.

Nocardia brasiliensis Infection Complicating Cryptogenic Organizing Pneumonia

OpenAIRE

Fernandes, Alison M.; Sluzevich, Jason C.; Mira-Avendano, Isabel

2017-01-01

Pulmonary nocardiosis is a severe and uncommon opportunistic infection caused by Nocardia species. We present a patient with cryptogenic organizing pneumonia who was receiving long-term immunosuppressive therapy, whose treatment course was complicated by cutaneous and pulmonary nocardiosis. Tissue cultures confirmed Nocardia brasiliensis. Nocardiosis should be a diagnostic consideration for patients treated with long-term immunosuppression who have worsening pulmonary symptoms and relapsing p...

Toxicological profile of deltamethrin in Triatoma brasiliensis (Hemiptera: Reduviidae) in State of Ceará, Northeastern Brazil.

Science.gov (United States)

Pessoa, Grasielle Caldas D'Ávila; Trevizani, Nathália Abreu Borges; Dias, Letícia Sena; Bezerra, Claudia Mendonça de; Melo, Bernardino Vaz de; Diotaiut, Liléia

2015-01-01

Triatoma brasiliensis is the species of greatest epidemiological relevance in the semi-arid region of Brazil. This species is predominantly found in domestic environments, and it has the ability to build large colonies with high levels of natural infection via Trypanosoma cruzi. Thus, T. brasiliensis is one of the most efficient transmitters of Chagas disease (CD) to humans. Despite household spraying with residual insecticides, many areas report persistent reinfestations for reasons that remain poorly understood. Therefore, this study sought to characterize the toxicological profile of deltamethrin in T. brasiliensis from areas with persistent reinfestation in State of Ceará, Brazil. The susceptibility reference lineage (SRL) was derived from Umari. Serial dilutions of deltamethrin were prepared and applied to the dorsal abdomen of first instar nymphs. The control group received only pure acetone. Mortality was evaluated after 72h. Qualitative tests assessed mortality in response to a diagnostic dose of 1xLD99 (0.851 nanograms of active ingredient per treated nymph) of the SRL. The susceptibility profile characterization of the T. brasiliensis populations revealed 50% resistance ratios (RR50) that ranged from 0.32 to 1.21. The percentage of mortality in response to the diagnostic dose was 100%. We demonstrated that T. brasiliensis was highly susceptible to deltamethrin. The control difficulties found might be related to the recolonization of the triatomines originating from neighboring environments and the possible operational failures related to the process of spraying that enabled specimens less susceptible to deltamethrin to survive.

UV-dependent production of 25-hydroxyvitamin D2 in the recombinant yeast cells expressing human CYP2R1

International Nuclear Information System (INIS)

Yasuda, Kaori; Endo, Mariko; Ikushiro, Shinichi; Kamakura, Masaki; Ohta, Miho; Sakaki, Toshiyuki

2013-01-01

Highlights: •We produce 25-hydroxyvitamin D in the recombinant yeast expressing human CYP2R1. •Vitamin D2 is produced in yeast from endogenous ergosterol with UV irradiation. •We produce 25-hydroxyvitamin D2 in the recombinant yeast without added substrate. -- Abstract: CYP2R1 is known to be a physiologically important vitamin D 25-hydroxylase. We have successfully expressed human CYP2R1 in Saccharomyces cerevisiae to reveal its enzymatic properties. In this study, we examined production of 25-hydroxylated vitamin D using whole recombinant yeast cells that expressed CYP2R1. When vitamin D 3 or vitamin D 2 was added to the cell suspension of CYP2R1-expressing yeast cells in a buffer containing glucose and β-cyclodextrin, the vitamins were converted into their 25-hydroxylated products. Next, we irradiated the cell suspension with UVB and incubated at 37 °C. Surprisingly, the 25-hydroxy vitamin D 2 was produced without additional vitamin D 2 . Endogenous ergosterol was likely converted into vitamin D 2 by UV irradiation and thermal isomerization, and then the resulting vitamin D 2 was converted to 25-hydroxyvitamin D 2 by CYP2R1. This novel method for producing 25-hydroxyvitamin D 2 without a substrate could be useful for practical purposes

Identification and Evaluation of Clinically Significant Nocardia brasiliensis, Nocardia farcinica and Nocardia otitidiscaviarum Strains Using Pyrolysis Mass Spectrometry (PyMS)

OpenAIRE

IŞIK, Kamil; KARİPTAŞ, Ergin; ŞAHİN, Nevzat

2001-01-01

Out of a total of thirty-nine Nocardia strains, eight species of N. brasiliensis, seventeen species of N. farcinica and fourteen species of N. otitidiscaviarum were identified using Pyrolysis mass spectrometry. N428, N477 N. brasiliensis; N669, N233 N. farcinica; and N231, N232 N. otitidiscaviarum duplicated strains were clustered in their own groups. Strains belonging to Nocardia brasiliensis, Nocardia farcinica and Nocardia otitidiscaviarum formed distinct pyrogroups corresponding to cluste...

Liver damages and nuclear abnormalities in erythrocytes of Atherinella brasiliensis (Actynopterigii, Atherinopsidade from two beaches in Southeast of Brazil

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Welingtom S. Fernandez

2011-06-01

Full Text Available There are few environmental studies using biomarkers for the species Atherinella brasiliensis in Brazil. In the present work, the presence of hepatic histopathological lesions and nuclear abnormalities in erythrocytes were investigated in A. brasiliensis from Lamberto, a beach under influence of domestic wastes and marine activities. For comparison, fish were also sampled in Puruba, a non-polluted beach, located in the northeastern of São Paulo State. The frequency of lesions found in liver was in higher numbers in individuals from Lamberto than Puruba beach. The most critical injuries observed in A. brasiliensis were the presence of necrotic areas, leucocytes infiltration and piknotic nucleus. A high occurrence of cells with vacuolization was also observed. The hepatic lesion index of the fish from Lamberto beach showed significant high values (Iorg=13 when compared with fish from Puruba beach (Iorg=7 suggesting the influence of the several human activities in the studied site. Notched and blebed nucleous were observed in this study, and significant differences were found between the studied sites. However, these differences did not reflect the total nuclear alterations.Existem poucos estudos no Brasil usando biomarcadores em Atherinella brasiliensis. No presente trabalho foram investigadas a presença de lesões histopatológicas hepáticas e as alterações nucleares em eritrócitos de A. brasiliensis amostrados na praia do Lamberto, local submetido à influência de resíduos domésticos e atividades humanas. Para comparação, indivíduos da espécie foram também amostrados na praia de Puruba, local não impactado, localizado no noroeste do estado de São Paulo. Peixes provenientes da praia do Lamberto apresentaram lesões hepáticas em número maior do que aqueles da praia de Puruba. Áreas necróticas, infiltração de leucócitos e núcleos picnóticos foram os danos de maior importância observados em A. brasiliensis, apesar de uma

The effects of 'cell age' upon the lethal effects of physical and chemical mutagens in the yeast, Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Parry, J.M.

1976-01-01

Yeast cultures progressing from the exponential to the stationary phase of growth showed changes in cell sensitivity to physical agents such as UV light, heat shock at 52 0 C and the chemical mutagens ethyl methane sulphonate, nitrous acid and mitomycin C. Exponential phase cells showed maximum resistance to heat shock and the three chemicals. The increased resistance of exponential phase cells to UV light was shown to be dependent upon the functional integrity of the RAD 50 gene. Treatment of growing yeast cultures with radioactively labelled ethyl methane sulphonate indicated the preferential uptake of radioactivity during the sensitive exponential stage of growth. The results indicated that the differential uptake of the chemical mutagens was responsible for at least a fraction of the variations in cell sensitivity observed in yeast cultures at different phases of growth. (orig.) [de

Comparative polygenic analysis of maximal ethanol accumulation capacity and tolerance to high ethanol levels of cell proliferation in yeast.

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Thiago M Pais

2013-06-01

Full Text Available The yeast Saccharomyces cerevisiae is able to accumulate ≥17% ethanol (v/v by fermentation in the absence of cell proliferation. The genetic basis of this unique capacity is unknown. Up to now, all research has focused on tolerance of yeast cell proliferation to high ethanol levels. Comparison of maximal ethanol accumulation capacity and ethanol tolerance of cell proliferation in 68 yeast strains showed a poor correlation, but higher ethanol tolerance of cell proliferation clearly increased the likelihood of superior maximal ethanol accumulation capacity. We have applied pooled-segregant whole-genome sequence analysis to identify the polygenic basis of these two complex traits using segregants from a cross of a haploid derivative of the sake strain CBS1585 and the lab strain BY. From a total of 301 segregants, 22 superior segregants accumulating ≥17% ethanol in small-scale fermentations and 32 superior segregants growing in the presence of 18% ethanol, were separately pooled and sequenced. Plotting SNP variant frequency against chromosomal position revealed eleven and eight Quantitative Trait Loci (QTLs for the two traits, respectively, and showed that the genetic basis of the two traits is partially different. Fine-mapping and Reciprocal Hemizygosity Analysis identified ADE1, URA3, and KIN3, encoding a protein kinase involved in DNA damage repair, as specific causative genes for maximal ethanol accumulation capacity. These genes, as well as the previously identified MKT1 gene, were not linked in this genetic background to tolerance of cell proliferation to high ethanol levels. The superior KIN3 allele contained two SNPs, which are absent in all yeast strains sequenced up to now. This work provides the first insight in the genetic basis of maximal ethanol accumulation capacity in yeast and reveals for the first time the importance of DNA damage repair in yeast ethanol tolerance.

Toxicology of the aqueous extract from the flowers of Butea monosperma Lam. and it's metabolomics in yeast cells.

Science.gov (United States)

Khan, Washim; Gupta, Shreesh; Ahmad, Sayeed

2017-10-01

Due to lack of scientific evidence for the safety of Butea monosperma (Fabaceae), our study aimed to carry out its toxicological profile and to identify its metabolic pattern in yeast cell. The effect of aqueous extract of B. monosperma flower on glucose uptake in yeast cell was evaluated through optimizing pH, temperature, incubation time, substrate concentration and kinetic parameters. Further, the metabolic pattern of extract as such and in yeast cell were analyzed by gas chromatography-mass spectrometry. Mice were administered aqueous extract up to 6000 and 4000 mg/kg for acute oral and intraperitoneal toxicity, respectively, while up to 4500 mg/kg for sub-acute oral toxicity (30 days). Elongation in the lag and log phase was observed in yeast cells supplemented with extract as compared to control. A maximum of 184.9% glucose uptake was observed whereas kinetic parameters (K m and V max ) were 1.38 and 41.91 mol/s, respectively. Out of 75 metabolites found in the extract, 14 and 18 metabolites were utilized by yeast cell after 15 and 30 min of incubation, respectively. The LD 50 of extract administered through intraperitoneal route was estimated to be 3500 mg/kg. The extract did not elicit any significant difference (P ≥ 0.05) in weight gain, food consumption, water intake, hematological, biochemical parameters and histological changes as compared to the normal control. Results ascertained the safety of B. monosperma flower extract which can be explored as potential candidates for the development of anti-diabetic phytopharmaceuticals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Do different degrees of human activity affect the diet of Brazilian silverside Atherinella brasiliensis?

Science.gov (United States)

Alves, V E N; Patrício, J; Dolbeth, M; Pessanha, A; Palma, A R T; Dantas, E W; Vendel, A L

2016-08-01

The aim of the present study was to test whether different degrees of human activity affect the diet of the Brazilian silverside Atherinella brasiliensis in two tropical estuaries. Fish were collected along the salinity gradient of two Brazilian estuaries, the heavily impacted Paraiba Estuary and the less impacted Mamanguape Estuary, in the dry and wet seasons. The findings confirm that A. brasiliensis has generalist feeding habits and is able to change its diet under different environmental conditions. The results indicate clear spatial (i.e. along the estuarine gradient) changes in diet composition in both estuaries, but diet was also influenced by the degree of anthropogenic disturbance. During the wet season in the nutrient enriched Paraiba Estuary, when human activity was higher, the diet of A. brasiliensis was poorer and dominated by few dietary items, reflecting the potential impoverishment of prey items in this heavily disturbed system. The specimens collected in the most affected estuary also had a greater frequency of micro-plastics and parasites in their stomachs, reflecting the greater degree of human disturbance in the estuary. The present findings suggest that the diet of A. brasiliensis could be a useful indicator of changes in the ecological quality of these and other tropical estuaries of the western Atlantic Ocean. © 2016 The Fisheries Society of the British Isles.

Proteins Potentially Involved in Immune Evasion Strategies in Sporothrix brasiliensis Elucidated by Ultra-High-Resolution Mass Spectrometry.

Science.gov (United States)

Rossato, Luana; Moreno, Leandro Ferreira; Jamalian, Azadeh; Stielow, Benjamin; de Almeida, Sandro Rogério; de Hoog, Sybren; Freeke, Joanna

2018-06-27

Sporothrix brasiliensis is the prevalent agent of a large zoonotic outbreak in Brazil. With the involvement of several thousands of cases, this is the largest cohort of human and animal sporotrichosis on record in the world. Infections are characterized by local cutaneous dissemination in humans without underlying disease. S. brasiliensis has shown a high degree of virulence in a mouse model compared to the remaining Sporothrix species, including the ancestral species, Sporothrix schenckii The present paper investigates a genomic and expressed-proteome comparison of S. brasiliensis to S. schenckii Using bottom-up proteomics, we found 60 proteins exclusively expressed in S. brasiliensis No significant genomic differences were found among the genes coding for this protein set. A comparison with literature data identified nine proteins that are known to be involved in virulence and immune evasion in other species, several of which had not yet been reported for the Sporothrix species analyzed. IMPORTANCE Sporotrichosis is an important disease in Brazil that is caused by fungi of the genus Sporothrix and affects cats and humans. Our work investigated the proteins differentially expressed by S. brasiliensis in order to find out why this species is more virulent and pathogenic than S. schenckii We verified a set of proteins that may be related to immune escape and that can explain the high virulence. Copyright © 2018 Rossato et al.

Yeast Killer Toxin K28: Biology and Unique Strategy of Host Cell Intoxication and Killing

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Björn Becker

2017-10-01

Full Text Available The initial discovery of killer toxin-secreting brewery strains of Saccharomyces cerevisiae (S. cerevisiae in the mid-sixties of the last century marked the beginning of intensive research in the yeast virology field. So far, four different S. cerevisiae killer toxins (K28, K1, K2, and Klus, encoded by cytoplasmic inherited double-stranded RNA viruses (dsRNA of the Totiviridae family, have been identified. Among these, K28 represents the unique example of a yeast viral killer toxin that enters a sensitive cell by receptor-mediated endocytosis to reach its intracellular target(s. This review summarizes and discusses the most recent advances and current knowledge on yeast killer toxin K28, with special emphasis on its endocytosis and intracellular trafficking, pointing towards future directions and open questions in this still timely and fascinating field of killer yeast research.

Daughter-specific transcription factors regulate cell size control in budding yeast.

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Di Talia, Stefano; Wang, Hongyin; Skotheim, Jan M; Rosebrock, Adam P; Futcher, Bruce; Cross, Frederick R

2009-10-01

In budding yeast, asymmetric cell division yields a larger mother and a smaller daughter cell, which transcribe different genes due to the daughter-specific transcription factors Ace2 and Ash1. Cell size control at the Start checkpoint has long been considered to be a main regulator of the length of the G1 phase of the cell cycle, resulting in longer G1 in the smaller daughter cells. Our recent data confirmed this concept using quantitative time-lapse microscopy. However, it has been proposed that daughter-specific, Ace2-dependent repression of expression of the G1 cyclin CLN3 had a dominant role in delaying daughters in G1. We wanted to reconcile these two divergent perspectives on the origin of long daughter G1 times. We quantified size control using single-cell time-lapse imaging of fluorescently labeled budding yeast, in the presence or absence of the daughter-specific transcriptional regulators Ace2 and Ash1. Ace2 and Ash1 are not required for efficient size control, but they shift the domain of efficient size control to larger cell size, thus increasing cell size requirement for Start in daughters. Microarray and chromatin immunoprecipitation experiments show that Ace2 and Ash1 are direct transcriptional regulators of the G1 cyclin gene CLN3. Quantification of cell size control in cells expressing titrated levels of Cln3 from ectopic promoters, and from cells with mutated Ace2 and Ash1 sites in the CLN3 promoter, showed that regulation of CLN3 expression by Ace2 and Ash1 can account for the differential regulation of Start in response to cell size in mothers and daughters. We show how daughter-specific transcriptional programs can interact with intrinsic cell size control to differentially regulate Start in mother and daughter cells. This work demonstrates mechanistically how asymmetric localization of cell fate determinants results in cell-type-specific regulation of the cell cycle.

Daughter-Specific Transcription Factors Regulate Cell Size Control in Budding Yeast

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Di Talia, Stefano; Wang, Hongyin; Skotheim, Jan M.; Rosebrock, Adam P.; Futcher, Bruce; Cross, Frederick R.

2009-01-01

In budding yeast, asymmetric cell division yields a larger mother and a smaller daughter cell, which transcribe different genes due to the daughter-specific transcription factors Ace2 and Ash1. Cell size control at the Start checkpoint has long been considered to be a main regulator of the length of the G1 phase of the cell cycle, resulting in longer G1 in the smaller daughter cells. Our recent data confirmed this concept using quantitative time-lapse microscopy. However, it has been proposed that daughter-specific, Ace2-dependent repression of expression of the G1 cyclin CLN3 had a dominant role in delaying daughters in G1. We wanted to reconcile these two divergent perspectives on the origin of long daughter G1 times. We quantified size control using single-cell time-lapse imaging of fluorescently labeled budding yeast, in the presence or absence of the daughter-specific transcriptional regulators Ace2 and Ash1. Ace2 and Ash1 are not required for efficient size control, but they shift the domain of efficient size control to larger cell size, thus increasing cell size requirement for Start in daughters. Microarray and chromatin immunoprecipitation experiments show that Ace2 and Ash1 are direct transcriptional regulators of the G1 cyclin gene CLN3. Quantification of cell size control in cells expressing titrated levels of Cln3 from ectopic promoters, and from cells with mutated Ace2 and Ash1 sites in the CLN3 promoter, showed that regulation of CLN3 expression by Ace2 and Ash1 can account for the differential regulation of Start in response to cell size in mothers and daughters. We show how daughter-specific transcriptional programs can interact with intrinsic cell size control to differentially regulate Start in mother and daughter cells. This work demonstrates mechanistically how asymmetric localization of cell fate determinants results in cell-type-specific regulation of the cell cycle. PMID:19841732

Daughter-specific transcription factors regulate cell size control in budding yeast.

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Stefano Di Talia

2009-10-01

Full Text Available In budding yeast, asymmetric cell division yields a larger mother and a smaller daughter cell, which transcribe different genes due to the daughter-specific transcription factors Ace2 and Ash1. Cell size control at the Start checkpoint has long been considered to be a main regulator of the length of the G1 phase of the cell cycle, resulting in longer G1 in the smaller daughter cells. Our recent data confirmed this concept using quantitative time-lapse microscopy. However, it has been proposed that daughter-specific, Ace2-dependent repression of expression of the G1 cyclin CLN3 had a dominant role in delaying daughters in G1. We wanted to reconcile these two divergent perspectives on the origin of long daughter G1 times. We quantified size control using single-cell time-lapse imaging of fluorescently labeled budding yeast, in the presence or absence of the daughter-specific transcriptional regulators Ace2 and Ash1. Ace2 and Ash1 are not required for efficient size control, but they shift the domain of efficient size control to larger cell size, thus increasing cell size requirement for Start in daughters. Microarray and chromatin immunoprecipitation experiments show that Ace2 and Ash1 are direct transcriptional regulators of the G1 cyclin gene CLN3. Quantification of cell size control in cells expressing titrated levels of Cln3 from ectopic promoters, and from cells with mutated Ace2 and Ash1 sites in the CLN3 promoter, showed that regulation of CLN3 expression by Ace2 and Ash1 can account for the differential regulation of Start in response to cell size in mothers and daughters. We show how daughter-specific transcriptional programs can interact with intrinsic cell size control to differentially regulate Start in mother and daughter cells. This work demonstrates mechanistically how asymmetric localization of cell fate determinants results in cell-type-specific regulation of the cell cycle.

Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis

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Goldenbogen, Björn; Giese, Wolfgang; Hemmen, Marie; Uhlendorf, Jannis; Herrmann, Andreas

2016-01-01

The cell wall defines cell shape and maintains integrity of fungi and plants. When exposed to mating pheromone, Saccharomyces cerevisiae grows a mating projection and alters in morphology from spherical to shmoo form. Although structural and compositional alterations of the cell wall accompany shape transitions, their impact on cell wall elasticity is unknown. In a combined theoretical and experimental approach using finite-element modelling and atomic force microscopy (AFM), we investigated the influence of spatially and temporally varying material properties on mating morphogenesis. Time-resolved elasticity maps of shmooing yeast acquired with AFM in vivo revealed distinct patterns, with soft material at the emerging mating projection and stiff material at the tip. The observed cell wall softening in the protrusion region is necessary for the formation of the characteristic shmoo shape, and results in wider and longer mating projections. The approach is generally applicable to tip-growing fungi and plants cells. PMID:27605377

Effect of whole yeast cell product supplementation (CitriStim®) on immune responses and cecal microflora species in pullet and layer chickens during an experimental coccidial challenge.

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Markazi, Ashley D; Perez, Victor; Sifri, Mamduh; Shanmugasundaram, Revathi; Selvaraj, Ramesh K

2017-07-01

Three separate experiments were conducted to study the effects of whole yeast cell product supplementation in pullets and layer hens. Body weight gain, fecal and intestinal coccidial oocyst counts, cecal microflora species, cytokine mRNA amounts, and CD4+ and CD8+ T-cell populations in the cecal tonsils were analyzed following an experimental coccidial infection. In Experiment I, day-old Leghorn layer chicks were fed 3 experimental diets with 0, 0.1, or 0.2% whole yeast cell product (CitriStim®, ADM, Decatur, IL). At 21 d of age, birds were challenged with 1 × 105 live coccidial oocysts. Supplementation with whole yeast cell product decreased the fecal coccidial oocyst count at 7 (P = 0.05) and 8 (P product and challenged with 1 × 105 live coccidial oocysts on d 25 of whole yeast cell product feeding. Supplementation with whole yeast cell product decreased the coccidial oocyst count in the intestinal content (P product increased relative proportion of Lactobacillus (P product decreased CD8+ T cell percentages (P product and challenged with 1 × 105 live coccidial oocysts on d 66 of whole yeast cell product feeding. At 5 d post-coccidial challenge, whole yeast cell product supplementation down-regulated (P = 0.01) IL-10 mRNA amount. It could be concluded that supplementing whole yeast cell product can help minimize coccidial infection in both growing pullets and layer chickens. © 2017 Poultry Science Association Inc.

Increase in virulence of Sporothrix brasiliensis over five years in a patient with chronic disseminated sporotrichosis.

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Freitas, Dayvison F S; Santos, Suelen S; Almeida-Paes, Rodrigo; de Oliveira, Manoel M E; do Valle, Antonio C F; Gutierrez-Galhardo, Maria Clara; Zancopé-Oliveira, Rosely M; Nosanchuk, Joshua D

2015-01-01

The metropolitan region of Rio de Janeiro is hyperendemic for cat-associated sporotrichosis. This study aimed to assess the virulence of serial Sporothrix isolates from a 61-year-old male patient with chronic, destructive disseminated sporotrichosis. Five Sporothrix isolates were cultured from skin exudates and bone samples over a 5-year period, and all were molecularly identified as Sporothrix brasiliensis. The final isolate was significantly more virulent in Galleria mellonella larvae compared to earlier isolates. We conclude that S. brasiliensis has the capacity to increase in virulence in vivo. This finding is significant to clinicians caring for individuals with S. brasiliensis disease and it suggests that further studies are needed to identify the mechanisms underlying pathogenicity enhancement during chronic disease.

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

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Cintia P.J. Rua

2014-06-01

Full Text Available 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.

Effect of Growth Conditions on Flocculation and Cell Surface Hydrophobicity of Brewing Yeast

Czech Academy of Sciences Publication Activity Database

Kopecká, J.; Němec, M.; Matoulková, D.; Čejka, P.; Jelínková, Markéta; Felsberg, Jürgen; Sigler, Karel

2015-01-01

Roč. 73, č. 2 (2015), s. 143-150 ISSN 0361-0470 Institutional support: RVO:61388971 Keywords : Ale and lager yeast * Cell surface hydrophobicity * FLO genes Subject RIV: EI - Biotechnology ; Bionics Impact factor: 0.492, year: 2015

In Vitro Activity of PNU-100766 (Linezolid), a New Oxazolidinone Antimicrobial, against Nocardia brasiliensis

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Vera-Cabrera, Lucio; Gómez-Flores, Alejandra; Escalante-Fuentes, Wendy G.; Welsh, Oliverio

2001-01-01

The in vitro activity of a novel oxazolidinone, linezolid, was studied by comparing the activity of linezolid with those of amikacin, trimethoprim-sulfamethoxazole, and amoxicillin-clavulanic acid against 25 strains of Nocardia brasiliensis isolated from patients with mycetoma. All N. brasiliensis strains tested were sensitive to linezolid (MIC at which 90% of strains are inhibited [MIC90], 2 μg/ml; MIC50, 1 μg/ml). This antimicrobial might constitute a good alternative for treatment of actinomycetoma. PMID:11709356

Humoral immunity through immunoglobulin M protects mice from an experimental actinomycetoma infection by Nocardia brasiliensis.

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Salinas-Carmona, Mario C; Pérez-Rivera, Isabel

2004-10-01

An experimental model of infection with Nocardia brasiliensis, used as an example of a facultative intracellular pathogen, was tested. N. brasiliensis was injected into the rear foot pads of BALB/c mice to establish an infection. Within 30 days, infected animals developed a chronic actinomycetoma infection. Batch cultures of N. brasiliensis were used to purify P61, P38, and P24 antigens; P61 is a catalase, and P38 is a protease with strong caseinolytic activity. Active and passive immunizations of BALB/c mice with these three purified soluble antigens were studied. Protection was demonstrated for actively immunized mice. However, immunity lasted only 30 days. Other groups of immunized mice were bled at different times, and their sera were passively transferred to naive recipients that were then infected with N. brasiliensis. Sera collected 5, 6, and 7 days after donor immunization conferred complete, long-lasting protection. The protective effect of passive immunity decreased when sera were collected 2 weeks after donor immunization. However, neither the early sera (1-, 2-, and 3-day sera) nor the later sera (30- or 45-day sera) prevented the infection. Hyperimmune sera with the highest levels of immunoglobulin G (IgG) to N. brasiliensis antigens did not protect at all. The antigens tested induced two IgM peaks. The first peak was present 3 days after immunization but was not antigen specific and did not transfer protection. The second peak was evident 7 days after immunization, was an IgM response, was antigen specific, and conferred protection. This results clearly demonstrate that IgM antibodies protect the host against a facultative intracellular bacterium.

31P NMR measurements of the ADP concentration in yeast cells genetically modified to express creatine kinase

International Nuclear Information System (INIS)

Brindle, K.; Braddock, P.; Fulton, S.

1990-01-01

Rabbit muscle creatine kinase has been introduced into the yeast Saccharomyces cerevisiae by transforming cells with a multicopy plasmid containing the coding sequence for the enzyme under the control of the yeast phosphoglycerate kinase promoter. The transformed cells showed creating kinase activities similar to those found in mammalian heart muscle. 31 P NMR measurements of the near-equilibrium concentrations of phosphocreatine and cellular pH together with measurements of the total extractable concentrations of phosphocreatine and creatine allowed calculation of the free ADP/ATP ratio in the cell. The calculated ratio of approximately 2 was considerably higher than the ratio of between 0.06 and 0.1 measured directly in cell extracts

Minimal inhibitory concentration distributions and epidemiological cutoff values of five antifungal agents against Sporothrix brasiliensis

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Rodrigo Almeida-Paes

Full Text Available BACKGROUND Sporothrix brasiliensis is the most virulent sporotrichosis agent. This species usually responds to antifungal drugs, but therapeutic failure can occur in some patients. Antifungal susceptibility tests have been performed on this species, but no clinical breakpoints (CBPs are available. In this situation, minimal inhibitory concentration (MIC distributions and epidemiological cutoff values (ECVs support the detection of identification of resistant strains. OBJECTIVES To study the MIC distributions of five antifungal drugs against S. brasiliensis and to propose tentative ECVs. METHODS MICs of amphotericin B (AMB, itraconazole (ITR, ketoconazole (KET, posaconazole (POS, and terbinafine (TRB against 335 S. brasiliensis strains were determined by the Clinical and Laboratory Standards Institute broth microdilution method. FINDINGS The proposed ECV, in µg/mL, for AMB, ITR, KET, POS, and TRB were 4.0, 2.0, 1.0, 2.0, and 0.25, respectively. Percentages of wild-type strains in our population for the above antifungal drugs were 98.48, 95.22, 95.33, 100, and 97.67%, respectively. MAIN CONCLUSIONS These ECVs will be useful to detect strains with resistance, to define CBPs, and to elaborate specific therapeutic guidelines for S. brasiliensis. Rational use of antifungals is strongly recommended to avoid the emergence of resistant strains and ensure the therapeutic effectiveness of sporotrichosis.

Extraction of brewer's yeasts using different methods of cell disruption for practical biodiesel production.

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Řezanka, Tomáš; Matoulková, Dagmar; Kolouchová, Irena; Masák, Jan; Viden, Ivan; Sigler, Karel

2015-05-01

The methods of preparation of fatty acids from brewer's yeast and its use in production of biofuels and in different branches of industry are described. Isolation of fatty acids from cell lipids includes cell disintegration (e.g., with liquid nitrogen, KOH, NaOH, petroleum ether, nitrogenous basic compounds, etc.) and subsequent processing of extracted lipids, including analysis of fatty acid and computing of biodiesel properties such as viscosity, density, cloud point, and cetane number. Methyl esters obtained from brewer's waste yeast are well suited for the production of biodiesel. All 49 samples (7 breweries and 7 methods) meet the requirements for biodiesel quality in both the composition of fatty acids and the properties of the biofuel required by the US and EU standards.

Nocardia brasiliensis Infection Complicating Cryptogenic Organizing Pneumonia

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Alison M. Fernandes

2017-01-01

Full Text Available Pulmonary nocardiosis is a severe and uncommon opportunistic infection caused by Nocardia species. We present a patient with cryptogenic organizing pneumonia who was receiving long-term immunosuppressive therapy, whose treatment course was complicated by cutaneous and pulmonary nocardiosis. Tissue cultures confirmed Nocardia brasiliensis. Nocardiosis should be a diagnostic consideration for patients treated with long-term immunosuppression who have worsening pulmonary symptoms and relapsing pustular skin lesions.

Morphological Changes of Yeast Cells due to Oxidative Stress by Mercury and Radiation

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Kim, Su Hyoun; Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2009-05-15

The yeast Saccharomyces cerevisiae is one of the most important microorganisms employed in industry. Growth rate, mutation, and environmental conditions affect yeast size and shape distributions but, in general, the influence of spatial variations in large-scale bioreactors is not considered. Ionizing radiation induces DNA double strand breaks in the nucleus, In addition, it causes lipid peroxidation, ceramide generation, and protein oxidation in the membrane, cytoplasm, and nucleus. Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. As a metal ion, it induces an oxidative stress or predisposes cells to an oxidative stress, with considerable damage to proteins, lipids and DNA. In this work, we investigated to effect of ionizing radiation (IR) and mercury chloride (II) on cell morphology.

Reptilia, Serpentes, Dipsadidae, Gomesophis brasiliensis (Gomes, 1918: Distribution extension in state of Santa Catarina, Brazil.

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Fortes, V. B.

2010-01-01

Full Text Available The Brazilian burrowing snake, Gomesophis brasiliensis, occurs in aquatic habitats such as swamps, from MinasGerais and Distrito Federal until Rio Grande do Sul. In spite of this wide distribution, the species’ geographic range stillremains unclear. This note reports the occurrence of G. brasiliensis in the municipality of Vargem Bonita, state of SantaCatarina, south Brazil, extending the species’ range ca. 80 km to the west in this state.

Heavy metals phytoremediation potential of Hevea brasiliensis in Bentong, Malaysia

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