Aplicação da técnica de fluorescência para avaliação de microrganismos visando a construção de biossensores

A identificação rápida e precisa de microrganismos constitui-se em etapa primordial e de extrema importância no diagnóstico de patologias, controle de qualidade na indústria de alimentos e agricultura. Desta forma, é necessário o desenvolvimento de um método que seja rápido, eficaz e de baixo custo. O uso da técnica de fluorescência tem como vantagens: (a) ser de baixo custo quando comparado com outras técnicas não fotônicas; (b) permitir a obtenção dos resultados em poucos segundos; (c) realizar as medidas in situ; (d) nenhuma ou pequena preparação de amostra é necessária e (e) não há geração de resíduos químicos. Nesse sentido, o objetivo deste trabalho foi aplicar a fluorescência para avaliação de microrganismos e, em especial, a ação do peptídeo antimicrobiano (PAM) polycerradin, com intuito de utilizá-lo como bioreceptor na confecção de biossensor. Os espectros de fluorescência para avaliação dos microrganismos puros e sob ação do PAM foram obtidos utilizando um espectrofluorímetro Shimadzu, RF-5301PC, com comprimento de onda de excitação fixo em 280 nm e um intervalo de detecção de 290-550 nm. Após crescimento em ágar, as suspensões microbianas foram preparadas em solução salina conforme orientações do CLSI. O PAM polycerradin foi solubilizado em água destilada esterilizada em uma concentração de 10 mg/mL. Para análise instrumental, foram depositados em uma cubeta 3 ml da suspensão microbiana e 0,5 ml do PAM (espectros foram obtidos em triplicata). A partir da análise dos espectros de emissão foi realizado um estudo comparativo entre a amostra microbiana antes e após a adição do PAM, tendo sido verificado que a intensidade de emissão para diversos microrganismos diminuiu em até 100 vezes após a adição do composto antimicrobianoFil: Perazzoli, Ivan L O. Universidade Federal de Sao Carlos (Brasil)Fil: Serrano, Nadja F G. Universidade Federal de Sao Carlos (Brasil)Fil: Araújo, Moreira. Universidade Federal de Sao Carlos (Brasil)Fil: Fernando, M. Universidade Federal de Sao Carlos (Brasil

Effect of prepartum administration of recombinant bovine somatotropin (rbST) on plasma beta-hydroxybutyrate levels in ewes subjected to subclinical ketosis.

O objetivo deste estudo foi determinar o efeito da rbST pré-parto no perfil de plasma BHB de ovelhas gestantes submetidas a cetose subclínica

Optimizing biomethane production from anaerobic degradation of Scenedesmus spp. biomass harvested from algae-based swine digestate treatment.

The objective of this work was to quantify biomethane from anaerobic degradation of microalgae biomass harvested from a field-scale tank reactor simulating phycoremediation of swine wastewater. The effects of nutrients starvation on microalgae chemical cellular composition changes and its influence on biomethane generation potential were also addressed. Microalgae polyculture was dominated by uncultured Scenedesmus clone BF 063 which showed a carbohydrate, protein and lipid content of 27.6 ± 3.3, 57.6 ± 0.1 and 3.9 ± 0.6%, respectively. After 25 days exposed to N- and P-free medium, microalgae biomass composition showed 54.6 ± 2.6, 24.1 ± 2.4 and 16.9 ± 0.8% of carbohydrate, protein and lipid, respectively. Volatile solids concentration in the biomass harvested from N- and P-rich medium was lower [67 ± 1.7 g VS (kg biomass)?1] than biomass harvested from nutrient depleted medium [204.1 ± 3.1 g VS (kg biomass)?1]. Consequently, much higher biomethane production was obtained i.e., 103.5 LN CH4 (kg biomass)?1 vs 44 LN CH4 (kg biomass)?1. The results suggest that biomethane production in digesters could be improved by integrating microalgae biomass harvested from algae-based swine wastewater digestate treatment

Effect of heat stress and solar radiation on dry matter intake, biochemical indicators, production, and quality of Holstein and Jersey cows' milk

ABSTRACT The objective of this work was to compare the dry matter intake, milk yield and quality, physiological and biochemical parameters in Holstein (n=10) and Jersey (n=10) cows under heat stress and insolation, in two treatments: CL - cooling by ventilation and sprinkling and HS - heat stress and insolation. Data were submitted to ANOVA. There was an interaction between treatment and breed and day effect for dry matter intake. For consumption in % of body weight, CL and Jersey cows consumed more. CL cows produced more milk and 3.5% fat-corrected milk. Feed efficiency was similar between treatments and breeds. Fat, lactose, total solids, and somatic cell score did not differ. The concentration of milk urea nitrogen was higher for CL cows. Milk from Holstein cows had greater stability to alcohol, and from HT cows had a greater freezing point of milk. HT cows had higher respiratory rates in the morning and surface temperatures in the afternoon. There were no differences in beta-hydroxybutyrate and glucose concentrations. Heat stress, with insulation, reduces intake, especially in Holstein cows, as well as milk production and increases the freezing point of milk, respiratory rate, and surface temperature

A HIF-independent, CD133-mediated mechanism of cisplatin resistance in glioblastoma cells

Purpose Glioblastoma Multiforme (GBM) is the commonest brain tumour in adults. A population of cells, known as cancer stem cells (CSCs), is thought to mediate chemo/radiotherapy resistance. CD133 is a cell surface marker to identify and isolate CSCs. However, its functional significance and the relevant microenvironment in which to study CD133 remain unknown. We examined the influence of hypoxia on CD133 expression and the potential functional significance of CD133 in glioblastoma chemoresistance. Methods Gene expression was analysed by qRT-PCR. siRNA technique was used to downregulate genes and confirmed by flow cytometry. IC50 values was evaluated with the Alamar blue assay. Results CD133 expression was upregulated in hypoxia in 2D and 3D models. There was increased resistance to chemotherapeutics, cisplatin, temozolomide and etoposide, in cells cultured in hypoxia compared to normoxia. siRNA knockdown of either HIF1a or HIF2a resulted in reduced CD133 mRNA expression with HIF2a having a more prolonged effect on CD133 expression. HIF2a downregulation sensitized GBM cells to cisplatin to a greater extent than HIF1a but CD133 knockdown had a much more marked effect on cisplatin sensitisation than knockdown of either of the HIFs suggesting a HIF-independent mechanism of cisplatin resistance mediated via CD133. The same mechanism was not involved in temozolomide resistance since downregulation of HIF1a but not HIF2a or CD133 sensitized GBM cells to temozolomide. Conclusion Knowledge of the mechanisms involved in the novel hypoxia-induced CD133-mediated resistance to cisplatin observed might lead to identification of new strategies that enable more effective use of current therapeutic agents