The larvicidal effect of the supernatant of Lactobacillus acidophilus ATCC 4356 on Toxocara canis.

Human toxocariasis is a parasitic anthropozoonosis that is difficult to treat and control. A previous study carried out with Lactobacillus acidophilus ATCC 4356 revealed that the cell free supernatant (CFS) of this probiotic killed 100% of Toxocara canis larvae in vitro. The present study aimed to investigate the characteristics of the CFS of L. acidophilus ATCC 4356, which may be involved in its larvicidal effects on T. canis. L. acidophilus ATCC 4356 was cultured, and lactic and acetic acids present in the CFS were quantified by high performance liquid chromatography (HPLC). The levels of pH and H2O2 were also analyzed. To assess the larvicidal effect of the CFS, this was tested pure and diluted (1:2 to 1:128) on T. canis larvae. High concentrations of lactic and acetic acids were detected in the CFS. The acidity of the pure CFS was observed at pH 3.8, remaining acidic at dilutions of 1:2 to 1:16. Regarding the in vitro larvicidal effect, 100% death of T. canis larvae was observed using the pure CFS and 1:2 dilution. Based on these results, it can be inferred that the presence of higher concentrations of organic acids and low pH of the medium contributed to the larvicidal activity of the CFS of L. acidophilus ATCC 4356. In addition, the maintenance of the larvicidal effect, even after dilution, suggests a greater chance of the larvicidal effect of this CFS against T. canis in vivo.

Application of Hot Water Extraction Techniques and the Principal Component Analysis to Study the Influence of Cultivation of Commercial Yerba Mate Samples on Their Mineral Profiles.

Consumption of organic food has grown much around the world in the last 20 years. Change in the profile of consumers who have increasingly sought a healthy diet is the major contributor to this phenomenon. In scientific literature, some studies have already shown the nutritional superiority of organic food in the individual evaluation of metabolites. However, few studies have assessed interaction among metabolites, especially the one between minerals and the food matrix. This information may have great relevance in determining the extractability of minerals, especially in food consumed through infusion, such as yerba mate, since this interaction can directly influence their solubility. Thus, this study aimed to use hot water extraction techniques (infusion and decoction) and the principal component analysis (PCA) to evaluate the differences between organic and conventional cultivation systems in absorption and availability of Ca, Mg, Fe, Mn, and Zn in yerba mate leaves and stems. The PCA showed that cultivation influences total mineral contents found in both leaves and stems. Results of extractability only showed differences in conventional leaf samples, from which all minerals under study were better extracted. Results point out a different interaction between minerals and the matrix, depending on the cultivation, and to the stronger interaction between the matrix and minerals in organic samples, a fact which leads to low availability of minerals for consumption.

Evaluation of the influence of cultivation on the total magnesium concentration and infusion extractability in commercial arabica coffee.

Coffee is considered an important source of organic nutrients and minerals, and these resources are strongly affected by agricultural management. Among the minerals, the element Mg is important, which is essential for both plants and humans. In this work, the effects of agricultural management on the absorption and storage of Mg by commercial, ground, roasted Arabica coffee were investigated. For this purpose, some Mg and P fractions were evaluated. It was observed that Mg stored in the grain was concentrated in the inorganic fraction, with an average extraction of 102% and in conventional samples and 119% in organic samples. These results suggest that in these samples Mg is probably largely presented as different inorganic salts. Phytate and organic acid salts are two possibilities discussed in this work that could explain this hypothesis. This can be corroborated by the extraction of Mg in the infusion of hot water.

Determination of As and in mineral waters by fast sequential continuous flow hydride generation atomic absorption spectrometry.

In this study, a novel analytical method which consists of a combination of Fast Sequential Flame Atomic Absorption Spectrometry (FS-FAAS) and Continuous Flow Hydride Generation Atomic Absorption Spectrometry (CF-HGAAS) is proposed. The method developed was employed for the sequential determination of As and Sb at sub-µg L-1 levels in bottled mineral waters. A strong enhancement in the analytical throughput was obtained when compared with the traditional mono-element CF-HGAAS with a quartz tube atomizer (QTA). Variables which would affect the method performance such as Ar flow rate, HCl and NaBH4 concentrations as well as delay and integration time were optimized. A flame atomic absorption spectrometer working in fast sequential mode was used in all experiments. After just 20 s of read delay, As and Sb were sequentially determined in 6 s (3 s each element). A 26-2 fractional factorial design was employed for studies of potential interferents with transition metals that could be present in mineral water samples. Limits of detection obtained for As and Sb were 0.15 and 0.14 µg L-1, respectively. The accuracy of the proposed method was checked by the use of 2 certified reference materials: Trace elements in water (NIST 1643e) and Trace metals in drinking water (HPS TMDW). Good agreement between certified and found concentrations was observed. Finally, As and Sb were determined in commercial bottled mineral water samples. Adequate sensitivity, high throughput and minimization of reagents and sample consumption are the attractive features of this new method.