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Abstract: This study presents the results of an analysis of crude oil and asphaltene samples using the MALDI TOF technique. Thirty crude petroleum samples (24.53–32.05 API gravity) obtained from a Brazilian refinery were used in this study. Asphaltenes were precipitated from the corresponding crude oil samples with n-heptane. Mass spectra were acquired with a MALDI TOF mass spectrometer in a mass range of 100–1000Da. The main purpose of this study was to analyze the composition of the asphaltene molecules extracted from oil samples according to their molecular composition (molecular weight and composition heteroatoms). The mean composition of the group analyzed was calculated as follows: 17% sulfur-containing molecules, 28% nitrogen-containing molecules, 19% oxygen-containing molecules, 12% sulfur–oxygen-containing molecules and 17% nitrogen–oxygen containing molecules; only 7% of the compounds contained only hydrogen and carbon in their composition. Finally, MALDI TOF analysis can be a very efficient process with a great potential for estimating the physicochemical properties of asphaltenes. A VBA (Visual Basic for Applications) algorithm allowed us to determine the elemental composition of components of asphaltene samples. The elemental composition showed that, despite having the same physical characteristics, the chemical composition of the samples was different. [Copyright &y& Elsevier]

This study aimed to assess the microbiological profile of conventional and organic vegetables grown in Brazilian farms through the detection of Salmonella and other Enterobacteriaceae. A total of 200 samples (100 conventional and 100 organic), including leafy greens, spices/herbs, and other unusual vegetables, were submitted to the enumeration of Enterobacteriaceae by plating on VRBG agar. Moreover, colonies of Enterobacteriaceae were randomly selected and submitted to identification by MALDI-TOF MS. Samples were also tested for Salmonella, using culture-based and PCR-based enrichment methods. The mean counts of Enterobacteriaceae in conventional and organic vegetables were 5.1 ± 1.5 and 5.4 ± 1.4 log CFU/g, respectively (P > 0.05). A total of 18 genera (including 38 species) of Enterobacteriaceae were identified, and the most frequent ones found in samples from both farming systems were Enterobacter (76%) and Pantoea (68%). Salmonella was identified in 17 samples (8.5%): nine (4.5%) in conventional and eight (4.0%) in organic vegetables. These results indicate that the farming system had no impact on the Enterobacteriaceae populations and rates of Salmonella and revealed unsatisfactory microbiological safety of some samples, mainly due to the presence of Salmonella. These findings highlight the need for control measures during vegetable production, regardless of the farming system, to reduce microbial contamination and the risks of foodborne illnesses., (© 2023. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Aims: To gather data on agricultural practices in organic farms in Sao Paulo, Brazil, and evaluate their relationship with the microbiological characteristics of samples collected along the production chain., Methods and Results: Practices data were based on field observations and interviews with farmers in 10 selected organic lettuce producing farms. Counts of Enterobacteriaceae and surveys for Salmonella were performed in samples of lettuce (before and after washing), fertilizers, irrigation and washing water, all collected in the same farm. Water samples were also tested for total coliforms and generic Escherichia coli. Isolated Enterobacteriaceae were identified by MALDI-TOF MS. Contamination of lettuce was influenced by some agricultural practices: chicken manure-based fertilization resulted in higher Enterobacteriaceae counts in lettuce when compared to other types of manure, whereas pre-washed lettuces presented lower microbial counts than non-pre-washed samples. Salmonella was detected in one lettuce sample by qPCR. Escherichia coli was detected in all irrigation water samples. All sample types contained Enterobacteriaceae species commonly reported as opportunistic human pathogens., Conclusions: The data highlight the need for improvement in the good agricultural practices in the studied farms., Significance and Impact of the Study: This study provides information on agricultural practices and microbiological characteristics of organic lettuce, contributing to the development of more accurate risk assessments., (© 2021 Society for Applied Microbiology.)

The venom of the neotropical social wasp Agelaia pallipes pallipes was fractionated by RP-HPLC resulting in the elution of seven fractions; the last two were re-fractionated under RP-HPLC by using isocratic elution conditions and the purity of the fractions were confirmed by using ESI-MS analysis. Both fractions are constituted of peptide components, which were sequenced by Edman degradation chemistry, resulting in the following sequences: Protonectin I-L-G-T-I-L-G-L-L-K-G-L-NH(2). Agelaia-MP I-N-W-L-K-L-G-K-A-I-I-D-A-L-NH(2). Both peptides are manually synthesized on solid-phase and functionally characterized by using Wistar rats cells. Protonectin is a non-hemolytic chemotactic peptide for polymorphonucleated leukocytes (PMNL), presenting some mast cell degranulating activity and potent antimicrobial action both against Gram-positive and Gram-negative bacteria. Agelaia-MP was characterized as a hemolytic mast cell degranulator toxin, presenting a poor antimicrobial action and no chemotaxis for PMNL.