The colon microcosm: a novel in vitro model to study Candida albicans colonisation of the human colon

Candida albicans colonises the gastro-intestinal (GI) tract of over 60% of the population. In severely ill or immune compromised patients, this fungus can escape the gut, disseminate through the body and cause systemic disease. Most research in the field has focused on defining traits that contribute directly to virulence; there are comparatively few studies which have addressed how C. albicans colonises and persists in the gut. Furthermore, such studies have typically been performed mouse models devoid of resident GI bacteria, completely neglecting the major impact of the local microbiota on GI colonisation. How, then, does C. albicans persist in the GI tract in the presence of the normal gut microbiota? To address this question, a novel in vitro two-phase anaerobic fermentation system that simulates the human colon microenvironment has been developed. This “colon microcosm” supports the growth of human faecal microbiota in liquid anaerobic colon medium (phase 1) and C. albicans growth on agar plugs which are added to the medium to mimic the epithelial surface (phase 2). The impact of C. albicans upon the faecal microbiota is monitored by examining the planktonic phase (phase 1), whilst the effect of the microbiota on the growth of C. albicans is monitored after extracting C. albicans cells from the agar plugs (phase 2). The results of assays carried out to validate the model will be presented, as will data from pilot studies which illustrate the potentially exploitable impact of the human GI microbiota from healthy individuals on C. albicans growth

Architecture of the dynamic fungal cell wall

The fungal cell wall is essential for growth and survival, and is a key target for antifungal drugs and the immune system. The cell wall must be robust but flexible, protective and shielding yet porous to nutrients and membrane vesicles and receptive to exogenous signals. Most fungi have a common inner wall skeleton of chitin and β-glucans that functions as a flexible viscoelastic frame to which a more diverse set of outer cell wall polymers and glycosylated proteins are attached. Whereas the inner wall largely determines shape and strength, the outer wall confers properties of hydrophobicity, adhesiveness, and chemical and immunological heterogeneity. The spatial organization and dynamic regulation of the wall in response to prevailing growth conditions enable fungi to thrive within changing, diverse and often hostile environments. Understanding this architecture provides opportunities to develop diagnostics and drugs to combat life-threatening fungal infections

Dissection of the Candida albicans class I chitin synthase promoters

We acknowledge financial support from the Biotechnology and Biological Sciences Research Council (10161), Medical Research Council (New Investigator Award to C.A.M.), the European Community FUNGALWALL and SIGNALPATH initiatives and the Wellcome Trust.Peer reviewedPublisher PD

Interaction between stock indices via changepoint analysis

Stock market indices from several countries are modelled as discretely sampled diffusions whose parameters change at certain times. To estimate these times of parameter changes we employ both a sequential likelihood-ratio test and a non-parametric, spectral algorithm designed specifically for time series with multiple changepoints. Finally, we use point-process techniques to model relationships between changepoints of different financial time series. Copyright © 2006 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55814/1/653_ftp.pd

Cell wall stress induces alternative fungal cytokinesis and septation strategies

Peer reviewedPublisher PD

Cell wall protection by the Candida albicans class I chitin synthases

Open Access funded by Medical Research Council Acknowledgments We thank Kevin Mackenzie in the Microscopy and Histology Core Facility (Institute of Medical Sciences, University of Aberdeen), and Donna MacCallum for helpful statistical advice. This work was supported by grants from the Wellcome Trust (0868827 and 080088) including a Wellcome Trust Strategic Award (097377) and an Investigator Award to NG (101873), an MRC New Investigator Award to ML (MR/J008230/1) and a PhD scholarship awarded to KP from the Ministry of Sciences and Technology and Chiang Mai University, Thailand. Author contributions are as follows: KP constructed strains, performed the majority of the experiments, analyzed the data and contributed to the preparation of the manuscript. JA produced Fig. S1 using the data from the phosphoproteomic analysis conducted by SP and AB. NG conceived and designed experiments, analyzed data and commented on drafts of the manuscript. ML constructed strains, conceived, designed and performed experiments, analyzed data and wrote the manuscript.Peer reviewedPublisher PD

Una ciudad, muchos sueños...

Históricamente ha habido una contradicción entre el derecho a la ciudad y la mercantilización de la urbanización. La continuidad en un modelo de ciudad fragmentada no solo aumenta la desigualdad en el acceso a la ciudad y a sus bienes y servicios sino que, además, limita el efecto de cualquier política redistributiva reproduciendo esa desigualdad.Este trabajo forma parte de la revista: Cuadernos de Coyuntura, número 5, editada por la Facultad de Ciencias Sociales de la Universidad Nacional de Córdoba, fue publicado el 23 de junio de 2021. Se encuentra dedicado a los: “Jóvenes. Pensar y sentir la pandemia”. Los trabajos han sido escritos por estudiantes de grado y las presentaciones por docentes de la misma Facultad. Es un espacio que nos permite escuchar las voces y los sentires de los jóvenes, en este particular momento que vive la sociedad toda. NDLR. Enlace al Portal de Revistas de la Universidad Nacional de Córdoba https://revistas.unc.edu.ar/index.php/CuadernosConyuntura/issue/view/2316publishedVersionFil: Lenardon, Silvano. Universidad Nacional de Córdoba. Facultad de Ciencias Sociales; Argentina

Ferramentas quimiométricas aplicadas no desenvolvimento de metodologia analítica para avaliação de adulteração em leite bovino por adição de soro do queijo por ATR-FTIR

No Brasil, o monitoramento da qualidade do leite é realizado pelo Ministério da Agricultura, Pecuário e Abastecimento (MAPA) através da Instrução Normativa n° 68 (IN 68). A qualidade do leite consumido é uma constante preocupação devido às fraudes descobertas nos últimos anos. Uma das fraudes mais comuns é a adulteração de leite por adição de soro de queijo; esta adição é proibida pela legislação brasileira para o leite destinado diretamente ao consumo. Essa fraude pode ser detectada através da determinação do índice de caseinomacropeptídeo (CMP). O CMP é um peptídeo específico do soro do queijo; deste modo é um marcador da adulteração. Neste trabalho foi desenvolvido um método analítico capaz de quantificar o CMP no leite empregando a Espectroscopia no Infravermelho Médio com Transformada de Fourier e Reflexão Total Atenuada (ATR-FTIR) e Quimiometria. A análise exploratória dos dados foi realizada através de Análise por Componentes Principais (PCA) e Análise de Agrupamentos Hierárquicos (HCA), os quais indicaram uma semelhança entre as amostras de leite cru (LC) e leite semidesnatado (LS) contaminadas com CMP, em virtude da presença de gordura nesses leites. Na PCA foi possível observar uma tendência de separação das amostras com distintas adições de CMP. Na análise dos modelos de regressão foram utilizados os algoritmos de Mínimos Quadrados Parciais (PLS), Mínimos Quadrados Parciais por Sinergismo de Intervalo (SIPLS) e Máquinas de Vetores de Suporte com Mínimos Quadrados (LS-SVM) para selecionar o modelo adequado para quantificação do CMP em amostra de leite. Desse modo o modelo de escolha foi o s4i16M com LS-SVM. Assim, o método proposto mostrou ser rápido, simples e econômico para detectar amostras de leite adulteradas com CMP, cujos resultados foram comparados com o método de referência, com boa correlação (R2 = 0,9984).In Brazil, the milk quality is conducted by the Ministry of Agriculture, Livestock and Supply (MAPA) through Normative Instruction No. 68 (IN 68) and it is a constant concern due to the discovered frauds in recent years. A common fraud that occurs in Brazilian milk is the milk whey addition; which is prohibited by Brazilian law for milk of direct consumption. This fraud can be detected by determining the Caseinemacropeptide index (CMP). Since the CMP is a specific peptide of whey, it can be used as marker of milk adulteration. In this work, an analytical method capable of quantifying the CMP in milk, using the Fourier Transform Infrared Spectroscopy (FTIR) and chemometrics, was developed. Exploratory data analysis was performed using Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). These methods indicated a similarity between the samples of raw milk and semi-skimmed milk contaminated with CMP. This similarity may be due to the presence of fat in these milks. In the scores of the PCA, it was possible to observe a trend of separation of samples with different CMP concentrations. It was used Partial Least Squares algorithms (PLS), Partial Least Squares with Interval Synergism (SIPLS) and Support Vector Machines with Least Squares (LS-SVM) algorithms as regression algorithms. The model of choice was the s4i16M with LS-SVM. The proposed method proved to be fast, simple and economical to detect milk samples adulterated with CMP. These results corroborated with the reference method (R2 = 0,9984)

Novas metodologias para determinação de origem de vinhos geúchos empregando espectrometria por fluorescência associada a quimiometria

Novas metodologias por espectrofluorimetria acoplada ás ferramentas quimiométricas foram desenvolvidas, visando a classificação de amostras de vinho tinto varietais produzidas em duas regiões do Rio Grande do Sul, considerando a sua origem geográfica. Como as propriedades fluorescentes de um composto químico podem variar em função do pH, e as mudanças estruturais resultantes do pH induzem alterações significativas nos seus espectros de fluorescência, foi possível separar e identificar também diferentes compostos químicos. Neste trabalho, foram analisadas 53 amostras de vinho tinto da região da Serra Gaúcha e 20 da região da Campanha, contemplando 10 variedades de uvas. O sinal de fluorescência registrado corresponde a nove matrizes de emissão (51 variáveis) de excitação (12 variáveis) (EEM) registradas em diferentes pH (3 até 11) gerando assim a matriz de dados representando os dados de ordem superior. Estes foram tratados pela Resolução Multivariada de Curvas com Mínimos Quadrados Alternantes (MCR-ALS) e one class method Data Driven Soft Independente Modelling of Class Analogy (DD-SIMCA) para construção dos modelos de classificação. Ainda foram selecionados dois pHs (3 e 7) bem como a fusão dos dados destes, para representar dados de 1ª ordem, que foram explorados por meio da aplicação dos algoritmos (ACO, GA e SW) para seleção de variáveis, para auxiliar no reconhecimento dos vinhos empregando análise discriminante linear. Como resultado, observou-se que a predição foi realizada com melhor taxa para o modelo SW quando realizado a fusão dos pH 3 com pH 7, resultando num modelo com taxa de acerto superior a 90%. Por outro lado, os resultados do MCR-ALS apresentaram ótima recuperação dos compostos fluorescentes presente nos vinhos tinto analisados, e o DD-SIMCA alta capacidade de reconhecimento geográfico. Isso mostra que a metodologia proposta pode ser utilizada como uma ferramenta eficaz para identificação e classificação de amostras de vinhos visando a rastreabilidade desse produto, quando consideradas as mais representativas regiões produtoras de vinho do Estado do Rio Grande do Sul.New methodologies for spectrofluorimetry coupled with chemometric tools were developed, aiming at the classification of red wine samples produced in two regions of Rio Grande do Sul, considering their geographical origin. As the fluorescent properties of a chemical compound can vary depending on the pH, and the structural changes resulting from the pH induce significant changes in its fluorescence spectra, it was possible to separate and identify different chemical compounds as well. In this work, 53 samples of red wine from the Serra Gaúcha region and 20 from the Campanha region were analyzed, covering 10 grape varieties. The registered fluorescence signal corresponds to nine emission matrices (51 variables) of excitation (12 variables) (EEM) registered at different pH (3 to 11) thus generating the data matrix representing the higher order data. These were treated by Multivariate Curve Resolution with Alternating Least Squares (MCR-ALS) and one class method Data Driven Soft Independent Modelling of Class Analogy (DD-SIMCA) to build the classification models. Two pHs (3 and 7) were also selected, as well as the fusion of their data, to represent 1st order data, which were explored through the application of the algorithms (ACO, GA and SW) to select variables, to assist in the recognition of wines using linear discriminant analysis. As a result, it was observed that the prediction was performed with a better rate for the SW model when the fusion of pH 3 with pH 7 was performed, resulting in a model with a hit rate greater than 90%. On the other hand, the results of the MCR-ALS showed an excellent recovery of the fluorescent compounds present in the analyzed red wines, and the DD-SIMCA high capacity for geographic recognition. This shows that the proposed methodology can be used as an effective tool for the identification and classification of wine samples aiming at the traceability of this product, when considered the most representative wine producing regions of the State of Rio Grande do Sul

Redox-related metabolites and gene expression modulated by sugar in sunflower leaves: similarities with Sunflower chlorotic mottle virus-induced symptom

Sugars are part of an integrated redox system, since they are key regulators of respiration and photosynthesis, and therefore of the levels of reducing power, ATP and ROS. These elements are major determinants of the cellular redox state, which is involved in the perception and regulation of many endogenous and environmental stimuli. Our previous findings suggested that early sugar increase produced during compatible Sunflower chlorotic mottle virus (SuCMoV) infection might modulate chlorotic symptom development through redox state alteration in sunflower. The purpose of this work was to characterize redox-related metabolites and gene expression changes associated with high sugar availability and symptom development induced by SuCMoV. The results show that sugar caused an increase in glutathione, ascorbate, pyridine nucleotides, and ATP. In addition, higher sugar availability reduced hydrogen peroxide and ΦPSII. This finding suggests that high sugar availability would be associated with cellular redox alteration and photoinhibitory process. The expression of the genes analyzed was also strongly affected by sugar, such as the down-regulation of psbA and up-regulation of psbO and cp29. The expression level of cytoplasmic (apx-1 and gr)- and chloroplastic (Fe-sod)-targeted genes was also significantly enhanced in sugar-treated leaves. Therefore, all these responses suggest that sugars induce chloroplastic redox state alteration with photoinhibition process that could be contributing to chlorotic symptom development during SuCMoV infection.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Rodriguez, Marianela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Muñoz, Nacira Belen. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Cátedra de Fisiología Vegetal; ArgentinaFil: Lenardon, Sergio Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Lascano, Hernan Ramiro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Cátedra de Fisiología Vegetal; Argentin