Fish diversity in the rivers that drain the Baixada Maranhense and the Mearim basin in northeastern Brazil.

The Baixada Maranhense Environmental Protection Area of the Brazilian state of Maranhão encompasses a biologically rich region that includes the basins of four principal rivers, the Mearim, Pericumã, Pindaré, and Turiaçu, which form a complex of wetlands. The present study provides a comprehensive inventory of the fish fauna of the rivers that drain the Baixada Maranhense based on the identification of voucher specimens that were deposited in a scientific collection. Expeditions were conducted between 2014 and 2020. The inventory identified a total of 100 fish species representing 79 genera, 34 families, and 11 orders, which are found in both freshwater and estuarine environments. Six (Potamotrygon orbignyi, Leporinus piau, Moenkhausia loweae, Serrasalmus spilopleura, Pachypops fourcroi and Peckoltia greedoi) of the 100 taxa identified here are considered to be new records for one or more of the basins surveyed during this study, based on the existing data, while four - Colossoma macropomum, Megaleporinus macrocephalus, Cichla sp. and Cichla kelberi - are not native. The most speciose orders were the Siluriformes and Characiformes, while the most diverse families were the Loricariidae, Characidae, Auchenipteridae, Cichlidae, and Serrasalmidae. These data are consistent with the findings of most of the previous studies of freshwater ecosystems in the Neotropical region, in particular those of the rivers of Maranhão. The results of the present study represent an important advance in the understanding of the diversity of the fish fauna of the Mearim, Pericumã, Pindaré, and Turiaçu rivers, which are still poorly studied, and have likely had their diversity underestimated up to now.

Effects of gibberellic acid concentration and fruit maturation stage on seed germination and vigor of pitahaya seedlings.

With increased interest in cultivation, the study of white-fleshed pitahaya (Selenicereus undatus (Haw.) D.R. Hunt, Cactaceae family) seedling production is of fundamental importance in the search for novel techniques to increase cultivation and guarantee homogeneous and productive orchards. The present study investigated the influence of various gibberellic acid (GA3) concentrations and fruit maturation stages on seed germination and vigor of white-fleshed pitahaya seedlings, considering the physiological quality of seedlings produced to support genetic breeding and conservation programs of the species. White-fleshed pitahaya seeds at two maturation stages (physiologically ripe and maintained at 10 °C in Biochemical Oxygen Demand incubators for three months) were treated with varying GA3 concentrations of 0, 50, 100, and 500 mg/L. We observed the influence of fruit storage on seedling germination, emergence, and growth as a function of GA3 concentration. According to the results, seeds extracted from ripe white-fleshed pitahaya fruits grown under the conditions tested here required GA3 application to increase seedling emergence and vigor, with optimal doses in the 150-300-mg/L range. In the case of pitahaya fruits intended for storage for future seed removal and maintained under the same sowing conditions, the application of higher doses of GA3 was necessary when compared to the previous condition, with a minimum dose of 500 mg/L GA3. The present study shows that the maturation stage of white-fleshed pitahaya fruits intended for seed removal influences the quality of seedlings; therefore, the use of seeds extracted from ripe pitahaya fruits without fermentation is more appropriate for the purpose.

An Optimized Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry Assay for the Determination of Ethyl Palmitate in Hair.

The use of hair as a matrix for the evaluation of chronic ethanol drinking behavior presents the advantage of a longer window of detection and higher specificity when compared to classical biochemical markers. The most recent recommendations the Society of Hair Testing (SOHT) indicate that ethyl palmitate (EtP) hair levels can be used to estimate the ethanol drinking behavior, alternatively to the combined measurement of four main fatty acid ethyl esters. In this study, solid-phase microextraction (SPME) conditions for the extraction of EtP from hair were optimized using response surface analysis, after a Box-Behnken experiment. Analyses were performed by GC-MS. The optimized HS-SPME conditions, using a PDMS-DVB (65 µm) fiber, were pre-adsorption time of 6 min, extraction time of 60 min and incubation temperature of 94°C. The linear range was 0.05 to 3 ng mg-1, with accuracy within 95.15-109.91%. Between-assay and within-assay precision were 8.58-12.53 and 6.12-6.82%, respectively. The extraction yield was 61.3-71.9%. The assay was applied to hair specimens obtained from 46 volunteers, all presenting EtP levels within the linear range of the assay. Using a statistically designed experiment, a sensitive SPME-GC-MS assay for the measurement of EtP in hair was developed and validated, requiring only 20 mg of hair.

Improved measurement of ethyl glucuronide concentrations in hair using UPLCMS/MS for the evaluation of chronic ethanol consumption.

The presence of Ethyl glucuronide (EtG) in hair provides a strong indication of ethanol consumption and its investigation is of interest in both clinical and forensic contexts because of the wide window of detection. However, due to the possibility of false negative results in cases of small ethanol intake or excessive hair washing, the combined measurement of ethyl palmitate (EtP) with EtG could be useful. In this study, a sensitive UHPLC-MS/MS procedure for the measurement of EtG in hair was developed and validated, using optimized sample preparation and chromatographic separation. Milled hair was extracted with water for 24 h at room temperature, followed by clean-up of the extract by ion-exchange solid phase extraction (SPE). Extraction was highly efficient, with yield of 96.93-101.06%. Chromatographic separation was performed with a Fluoro-Phenyl stationary phase. The assay was linear from 4 to 500pgmg-1, with accuracy in the range of 100.30-106.16%. Matrix effects (-0.87 to 5.89%) were adequately compensated by the use of deuterated EtG as internal standard. EtG was measured in hair samples of 46 volunteers, and results were compared with hair concentrations of ethyl palmitate (EtP) and the score in the AUDITC questionnaire. EtG hair concentrations were significantly correlated to the AUDIT-C classification (rs=0.365, p<0.05), but not to EtP hair levels. The diagnostic performance of EtG hair concentrations to identify excessive or moderate ethanol use was similar to the capability of AUDIT-C to identify severe and high health risk (Kappa, p=0.013). The developed assay is suitable for clinical use, providing a useful tool to evaluate chronic ethanol consumption.

Kinetics of vacuum and air cooling of chicken breasts arranged in stacks.

The aim of this study was to compare the vacuum and air cooling of cooked chicken breast samples arranged in stacks with one, two and three layers (1 kg per layer). The cooling rate obtained with vacuum cooling was approximately three times faster than that of air cooling. Moreover, a more homogeneous cooling was obtained with vacuum cooling, with similar temperature reductions for samples at different positions of the stack. On the other hand, vacuum cooling led to mass losses of 11-12%, while air cooling led to losses of 7-8%. The counts of mesophiles and psychrophiles of the vacuum-cooled samples were lower than those observed for air-cooled samples after ten days of product storage. Thus, the results presented in this work illustrate the potential benefits and disadvantages of the vacuum cooling technique as compared to the air cooling, especially for the processing of small meat cuts.