ABSTRACT. One of the main objectives of sugarcane plantations is to increase their longevity without decreasing agricultural productivity. In the present study, we analyzed the proteome of the axillary buds of ‘RB966928’ to investigate possible changes in the number of proteins at different cutting stages. Using tryptic digestion followed by ultra-performance liquid chromatography coupled with high-resolution time-of-flight mass spectrometry, 122 proteins were identified from the proteome of the axillary buds of ‘RB966928’. Of the 122, respectively 97 and 95 proteins were detected at the first and fifth cutting stages, of which 27 and 25 proteins were unique to the respective stage. Proteins that prevent the misfolding of polypeptides generated under stress were exclusively detected at the first cutting stage. Meanwhile, proteins associated with stress responses and disease resistance were exclusively detected at the fifth cutting stage. The present proteomic analysis in the regrowth cycles and axillary bud development of ‘RB966928’ significantly advanced our understanding of the biological processes linked to the reduction of agricultural productivity of sugarcane with the advancement of cutting age. Absence of proteins to tolerate adverse growth conditions at the fifth cutting stage may be related to reduced agricultural productivity, in addition to environmental stress, soil compaction, nutrient availability, cultural practices, and pests or pathogen attacks at different phenological stages of crops.

Abstract This study aimed to investigate the antimicrobial activity of kefir fermented fruit by-products against strains of Alicyclobacillus spp., and determine their chemical characterization and antioxidant activity. According to the results, extracts fermented for a longer period (72 h) showed greater inhibition, and the extract of acerola by-product fermented for 72 h achieved the best results. For all strains, the Minimal Inhibitory Concentration (MIC) was 0.78%, except for A. acidocaldarius subsp. rittmannii, (1.56%). The same applies to the Minimal Bactericidal Concentration (MBC), in which 1.56% of the extract was capable of inactivating A. cycloheptanicus and A. acidocaldarius. In addition, damages to the structure of the microorganisms caused by the extracts were detected by Scanning Electron Microscopy. Metabolite identification through liquid chromatography (UHPLC-Qtof-MS) showed that the fermented extracts had a greater number of compounds compared to the non-fermented ones, such as glucuronic, succinic and glutaric acids. In conclusion, the extracts of fruit by-products showed to have bioactive properties, such as antibacterial potential and antioxidant activity against the Alicyclobacillus strains tested in this study, not to mention the value added by the use of a food by-product.

A determinação de herbicidas 2-metiltio-4,6-dialquilamino-1,3,5-triazina (triazinas) em soluções salinas utilizadas em hemodiálise foi investigada por voltametria. Os herbicidas foram detectados com grande sensibilidade nas soluções salinas, após extração em fase de acetonitrila (ACN), utilizando o eletrodo de mercúrio de gota pendente. O efeito de salting out originado pelo meio salino existente nas soluções viabilizou as extrações. A relação de volumes entre as fases salina e de ACN foi investigada para alcançar a melhor sensibilidade na detecção das triazinas. A especiação entre as triazinas investigadas (ametrina, desmetrina, prometrina e terbutrina) não foi possível e recuperações entre 88 e 107% foram calculadas em amostras fortificadas com os analitos. Utilizando esta metodologia, limites de detecção de 0,03 mimol L-1 foram calculados para as triazinas nas amostras salinas.

A method for the voltammetric determination of 2-methylthio-4,6-dialkylamino-1,3,5-triazine (triazines) herbicides in hemodialysis (HD) saline solutions was developed. The herbicides were detected in the saline solutions at the hanging mercury drop electrode (HMDE) with high sensitivities only after extraction of the analytes in acetonitrile (ACN). The salting out effect originated by the saline environment existing in the solutions enabled the extractions. The volume ratio between the saline and ACN phases was investigated in order to find the best sensitivity to detect the triazines. The speciation amongst them (ametryn, desmetryn, prometryn and terbutryn) was not possible. Recoveries between 88 and 107% were calculated in spiked samples, and detection limits of 0.03 mumol L-1 were calculated for the triazines in the saline samples using this methodology.