Evaluation of hardening and darkening of common beans during storage by HR-MAS NMR.

Use the NMR to analyze the variation in the metabolic profile of bean cultivars stored at controlled temperatures and modified atmosphere. Establishing the correlation between the metabolic variation with darkening and hardening grains proposing the best storage condition

Diferenciação de cultivares de feijão de origem transgênica e convencional por RMN HR-MAS de 1H e análise quimiométrica.

O objetivo do presente estudo foi avaliar as diferenças na composição química dos grãos dos cultivares Olathe Pinto convencional e o seu geneticamente modificado (Olathe Pinto 5.1) e uma possível transferência gênica aos cultivares Pontal e Perola, utilizando a ressonância magnética nuclear, em análise particular da técnica HR-MAS, e técnicas quimiométricas.Conpeex 2010

Effect of broiler breast abnormality and freezing on meat quality and metabolites assessed by 1H-NMR spectroscopy

ABSTRACT The present study aimed at investigating the impact of the current growth-related abnormalities (White-Striping—WS, Wooden Breast—WB, and Spaghetti Meat—SM) affecting broilers Pectoralis major muscles on the main quality traits, the oxidative stability of both the lipid and protein fraction as well as the water mobility assessed in fresh and frozen/thawed meat. In addition, Nuclear Magnetic Resonance spectroscopy (1 H-NMR) was applied to quantify free amino acids, histidine-containing dipeptides and metabolites involved in energy-generating pathways. Overall, the occurrence of WS, WB, and SM abnormalities remarkably affected the quality traits (pH, color, and water holding capacity) and oxidative stability of the meat, with the WB condition leading to the most detrimental effects. However, overall, freezing and subsequent thawing only partially worsened the aforementioned traits. Significant variations in free amino acids and histidine-containing dipeptides were found between abnormal muscles and their unaffected counterpart by 1 H-NMR spectroscopy and, aside from the occurrence of muscular defects, their content was remarkably reduced in frozen/thawed meat. The findings obtained by analyzing the metabolites through 1 H-NMR spectroscopy allowed to advance the knowledge concerning the impact of freezing and subsequent thawing on meat quality traits and provided useful information concerning the underlying mechanisms responsible for the development of WS, WB, and SM abnormalities in broilers

Efeito da planta hospedeira na suscetibilidade da mosca-branca, Bemisia tabaci biótipo B a inseticidas sintéticos.

Estudos têm demonstrado que a planta hospedeira pode afetar a susceptibilidade da Bemisia tabaci a inseticidas ou induzir a produção de enzimas específicas no inseto que são altamente efetivas em detoxificar inseticidas sintéticos. Baseado nessas evidências foi conduzido experimento para determinar o efeito da soja, algodão e feijão na suscetibilidade de B. tabaci a thiamethoxam 250 WG a 200 g p.c./ha, acefato 750 BR a 600 g p.c/ha e endosulfan 350 EC a 1500 ml p.c./ha.Resumo

Gaping of pectoralis minor muscles: magnitude and characterization of an emerging quality issue in broilers

Recently, a certain number of broiler abattoirs located in different Countries around the World have signaled an emerging quality issue termed "gaping" because of the separation of the fiber bundles affecting the external portion of the bipinnate pectoralis minor muscle. Thus, after defining the criteria to classify the muscles as Normal (NORM), Moderate (MOD), or Severe (SEV) cases, the incidence of gaping under commercial conditions was assessed on a total of 8,600 P. minor obtained from broiler chickens belonging to 43 flocks during a 6-mo period. Then, a total of 180 P. minor were selected based on previously defined criteria to evaluate the main quality traits (pH, color, water-holding/-binding capacity and tenderness), proximate composition, water mobility, and thermal properties as well as metabolic profile through 1H-Nuclear Magnetic Resonance spectroscopy. The average incidence of gaping defect was found to be 16.8% (8.8 and 8.0% MOD and SEV cases, respectively). As for the main quality traits, a reduction in ultimate pH was observed as the severity of the gaping defect increased, with SEV muscles displaying significantly lower values in comparison with NORM (5.96 vs. 6.02; P < 0.01), while MOD showed intermediate values (5.99). Concurrently, if compared with their NORM counterpart, MOD and SEV exhibited higher lightness (53.6 and 54.2 vs. 51.8; P < 0.01) coupled with higher (P < 0.05) cooking losses and longer (P < 0.05) transversal relaxation time of extra-myofibrillar water fraction. Overall, no significant differences were found concerning proximate composition and thermal properties. With regard to the metabolic profile, a significantly lower (P < 0.001) glutamine concentration was found in MOD and SEV muscles that, concurrently, revealed significant (P < 0.05) variations in the metabolites involved in energy-generating pathways. Overall, these findings evidenced that the gaping defect affecting broilers' P. minor muscles have strong similarities with the pale-soft-exudative condition previously described in poultry and likely results from the biochemical processes taking place during the post-mortem conversion of muscle to meat

MECHANOCHEMISTRY APPLIED TO THE SYNTHESIS OF 2-PHENYLIMIDAZO[1,2-α]PYRIDINE AS A TEACHING TOOL FOR GREEN CHEMISTRY

In the present work, we developed an experimental class for undergraduate students concerning the linear synthesis of 2-phenylimidazo[1,2-α]pyridine through mechanochemical techniques. This approach aims to conceptualize the green chemistry principles through a safe, robust, atom-economic, energy-efficient, and solvent-free method for preparing these classes of compounds by manual grinding and vortex mixing. The methodology was easily applied in experimental classes for chemistry students and could be easily expanded to other courses such as pharmacy and biotechnology

Anti-Staphy peptides rationally designed from Cry10Aa bacterial protein.

Bacterial infections pose a significant threat to human health, constituting a major challenge for healthcare systems. Antibiotic resistance is particularly concerning in the context of treating staphylococcal infections. In addressing this challenge, antimicrobial peptides (AMPs), characterized by their hydrophobic and cationic properties, unique mechanism of action, and remarkable bactericidal and immunomodulatory capabilities, emerge as promising alternatives to conventional antibiotics for tackling bacterial multidrug resistance. This study focuses on the Cry10Aa protein as a template for generating AMPs due to its membrane-penetrating ability. Leveraging the Joker algorithm, six peptide variants were derived from α-helix 3 of Cry10Aa, known for its interaction with lipid bilayers. In vitro, antimicrobial assays determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) required for inhibiting the growth of Staphylococcus aureus, Escherichia coli, Acinetobacter baummanii, Enterobacter cloacae, Enterococcus facallis, Klebsiella pneumonia, and Pseudomonas aeruginosa. Time-kill kinetics were performed using the parental peptide AMPCry10Aa, as well as AMPCry10Aa_1 and AMPCry10Aa_5, against E. coli ATCC, S. aureus 111 and S. aureus ATCC strains showing that AMPCry10Aa_1 and AMPCry10Aa_5 peptides can completely reduce the initial bacterial load with less than 2 h of incubation. AMPCry10Aa_1 and AMPCry 10Aa_5 present stability in human serum and activity maintenance up to 37 °C. Cytotoxicity assays, conducted using the MTT method, revealed that all of the tested peptides exhibited cell viability >50% (IC50). The study also encompassed evaluations of the structure and physical-chemical properties. The three-dimensional structures of AMPCry10Aa and AMPCry10Aa_5 were determined through nuclear magnetic resonance (NMR) spectroscopy, indicating the adoption of α-helical segments. Electron paramagnetic resonance (EPR) spectroscopy elucidated the mechanism of action, demonstrating that AMPCry10Aa_5 enters the outer membranes of E. coli and S. aureus, causing substantial increases in lipid fluidity, while AMPCry10Aa slightly increases lipid fluidity in E. coli. In conclusion, the results obtained underscore the potential of Cry10Aa as a source for developing antimicrobial peptides as alternatives to conventional antibiotics, offering a promising avenue in the battle against antibiotic resistance

DETERMINAÇÃO DA EXPOSIÇÃO DO PEPTÍDEO ANTIMICROBIANO CLAVANIN A EM MEIO MIMÉTICO, UTILIZANDO A TÉCNICA DE RESSONÂNCIA MAGNÉTICA NUCLEAR

Resson&acirc;ncia magn&eacute;tica nuclear (RMN), &eacute; uma t&eacute;cnica bastante utilizada para estudar as intera&ccedil;&otilde;es ligante-alvo de mol&eacute;culas biologicamente ativas1. As clavaninas s&atilde;o pept&iacute;deos encontrados nas c&eacute;lulas do sangue do tunicado Styelaclava2. Este pept&iacute;deo apresenta um amplo espectro de atividades contra bact&eacute;rias Gram-positivas e Gram-negativas, al&eacute;m de v&aacute;rios fungos2,3. Desta forma, o presente estudo tem como objetivo observar as intera&ccedil;&otilde;es moleculares do pept&iacute;deo clavanin A (sequ&ecirc;ncia: VFQFLGKIIHHVGNFVHGFSHVF-NH3), em diferentes meios. Para isto foram realizados experimentos de 1H com 1 mM do pept&iacute;deo, 90% de H2O e 10% D2O, TMSP-d4, pH 4.3 e 25&deg;C. Prepararam-se uma mostra utilizando SDS-d25, que mimetiza membrana bacteriana, e outra com 35% de TFE-d3 (co-solvente). As intensidades dos sinais de pr&oacute;tons arom&aacute;ticos podem sugerir a exposi&ccedil;&atilde;o do pept&iacute;deo na fase aquosa4. Em solu&ccedil;&atilde;o os pr&oacute;tons arom&aacute;ticos deste pept&iacute;deo apareceram na regi&atilde;o entre 7,10 e 7,44 ppm. Os dados mostraram a atenua&ccedil;&atilde;o dos sinais das cadeias laterais das fenilalaninas, nas posi&ccedil;&otilde;es 2, 4, 15, 19 e 23 dos H&delta; e H&epsilon;, na presen&ccedil;a de solu&ccedil;&atilde;o de TFE-d3, comparados aos respectivos pr&oacute;tons quando em micelas de SDS-d25. Tomados em conjunto o comportamento dos deslocamentos qu&iacute;micos junto com os dados de coeficiente de difus&atilde;o ordenada, sugere-se uma intera&ccedil;&atilde;o hidrof&oacute;bica entre o pept&iacute;deo antimicrobiano e o meio mim&eacute;tico de SDS, de forma que seus an&eacute;is arom&aacute;ticos de fenilalaninas penetrem ou estejam parcialmente localizados no interior da micela ou em sua dire&ccedil;&atilde;o. Portanto, a t&eacute;cnica de RMN forneceu informa&ccedil;&otilde;es a respeito das intera&ccedil;&otilde;es do pept&iacute;deo, possibilitando descrever os res&iacute;duos importantes nas intera&ccedil;&otilde;es moleculares com o alvo biol&oacute;gico, conhecimentos essenciais no desenvolvimento de novos f&aacute;rmacos. Agradecemos ao apoio financeiro do Conselho Nacional de Desenvolvimento Cient&iacute;fico e tecnol&oacute;gico