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Quorum sensing (QS) is cell-cell communication mechanism mediated by signaling molecules known as autoinducers (AIs) that lead to differential gene expression. Salmonella is unable to synthesize the AI-1 acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. Our study aimed to evaluate the influence of AI-1 on the abundance of proteins and the levels of organic acids of Salmonella Enteritidis. The presence of N-dodecyl-homoserine lactone (C12-HSL) did not interfere on the growth or the total amount of extracted proteins of Salmonella. However, the abundance of the proteins PheT, HtpG, PtsI, Adi, TalB, PmgI (or GpmI), Eno, and PykF enhanced while the abundance of the proteins RplB, RplE, RpsB, Tsf, OmpA, OmpC, OmpD, and GapA decreased when Salmonella Enteritidis was anaerobically cultivated in the presence of C12-HSL. Additionally, the bacterium produced less succinic, lactic, and acetic acids in the presence of C12-HSL. However, the concentration of extracellular formic acid reached 20.46 mM after 24 h and was not detected when the growth was in the absence of AI-1. Considering the cultivation period for protein extraction, their abundance, process and function, as well as the levels of organic acids, we observed in cells cultivated in presence of C12-HSL a correlation with what is described in the literature as entry into the stationary phase of growth, mainly related to nitrogen and amino acid starvation and acid stress. Further studies are needed in order to determine the specific role of the differentially abundant proteins and extracellular organic acids secreted by Salmonella in the presence of quorum sensing signaling molecules.

ResumoEste trabalho teve como objetivos a quantificação de proteínas e da atividade da enzima α-galactosidase, no eixo embrionário e nos cotilédones, de sementes de Dalbergia nigra (jacarandá-da-bahia) durante a germinação. as sementes foram colocadas para embeber em água por sete dias, sendo retiradas amostras para a avaliação bioquímica e cinética da enzima. a atividade da enzima α-galactosidase aumenta com a embebição das sementes nos dois compartimentos, embora não esteja presente no eixo embrionário de sementes secas. a diferença na atividade da enzima entre os cotilédones e o eixo embrionário foi significativa. o pH 5,5 foi o de máxima atividade para as enzimas de ambos os compartimentos. a temperatura que mais estimulou a atividade da enzima nos cotilédones foi 50 °C e de 50 a 60 °C no eixo embrionário. a atividade da α-galactosidase foi inibida por β-mercaptoetanol e cobre, em ambos os compartimentos, enquanto a lactose e o cloreto de sódio estimularam a atividade tanto nos cotilédones como no eixo embrionário. os valores de K M para enzimas do eixo embrionário e dos cotilédones foram de 0,239 e 0,228 mM, respectivamente. PalavRas-Chave: enzima, jacarandá-da-bahia, bioquímica. Proteins and activity of α-galactosidases determination in cotyledons and embryonic axis of Dalbergia nigra seeds during germination abstRaCtThis work aimed to quantify the protein content and the α-galactosidase activity in the embryonic axis and in the cotyledons of Dalbergia nigra seeds during the imbibition period. The seeds were submitted to water imbibition during seven days. Biochemical and kinetic characterization of the enzyme were done from samples taken during the imbibition period. The activity of the α-galactosidase increased in the two compartments with the soaking of the seeds, although, the enzyme activity was not detected in the embryonic axis of dry seeds. The difference in the activity of the enzyme between cotyledons and embryonic axis was significant. The pH of maximum activity was 5.5 for the enzyme of both compartments. in the cotyledons the higher activity of the enzyme was obtained at 50 °C. in the embryonic axis the activity was higher at temperatures ranging from 50 to 60 °C. The activity of the α-galactosidase was inhibited by β-mercaptoethanol and Cuso 4 in both compartments, while lactose and sodium chloride stimulated the activity in the cotyledons and in the embryonic axis. The values of K M for the enzymes of the embryonic axis and cotyledons were respectively 0.239 and 0.228 mM.

RESUMO:Extratos aquosos da planta medicinal Achillea millefolium contêm macromoléculas de interesse para desenvolver fitodefensivos para a agricultura. Duas frações de mil folhas foram obtidas por ultrafiltração, E1 (contendo moléculas maiores que 30 kDa), e E3 (peptídeos entre 1 e 10 kDa) que inibiram o crescimento das bactérias fitopatogênicas Ralstonia solanacearum, gramnegativa, e Clavibacter michiganensis subsp. michiganensis, gram-positiva, com dependência de concentração. Os valores de concentração inibitória mínima (CIM) para ambos os extratos e bactérias foram baixos, entre 20 e 80mM. A CIM relativa à proteína total evidenciou a presença de macromoléculas muito ativas em E3, embora com baixa concentração proteica. E3 se aplica à prospecção de peptídeos antimicrobianos. Estimar a CIM relativa à quantidade de amostra vegetal valorizou o potencial antimicrobiano natural de E1, que contém alta concentração proteica. E1e E3 se aplicam ao desenvolvimento de fitodefensivos para uso biotecnológico. A ultrafiltração fracionou as amostras de forma nativa, rápida, e com baixo custo; além de dessalinizar, clarificar, purificar, e concentrar E1 e E3. Esse estudo inédito sobre a separômica e a ação antimicrobiana de extratos macromoleculares aquosos de mil folhas sugere que plantas cicatrizantes podem apresentar grande potencial para desenvolver fitodefensivos agrícolas naturais não danosos, à semelhança de medicamentos fitoterápicos.Palavras-chave: Macromoléculas de defesa, peptídeos antimicrobianos, Ralstonia solanacearum, Clavibacter michiganensis subsp. michiganensis, concentração inibitória mínima relativa.ABSTRACT: Agrochemicals in medicinal plants: hydrophilic macromolecules from leaves of "mil folhas" (Achillea millefolium L.) inhibit in vitro growth of phytopathogenic bacteria. Aqueous extracts from the medicinal plant Achillea millefolium contain macromolecules of interest to develop agrochemicals for agriculture. Two fractions of "mil folhas" were obtained by ultrafiltration, E1 (containing molecules larger than 30 kDa) and E3 (peptides between 1 and 10 kDa), which inhibited the growth of phytopathogenic bacteria Ralstonia solanacearum, gramnegative, and Clavibacter michiganensis subsp. michiganensis, gram-positive, concentrationdependent. The values of minimum inhibitory concentration (MIC) for both extracts and both bacteria were low, ranging from 20 to 80mM. The MIC relative to total protein evidenced the presence of very active macromolecules in E3, although showing low protein concentration. E3 applies to the prospection of antimicrobial peptides. The estimated MIC relative to the amount of plant sample valued the natural antimicrobial potential of E1, which contains high protein concentration. E1 and E3 can be used in the development of agrochemicals for biotechnological purposes. The ultrafiltration procedure fractionated the samples in a rapid and native way and at a low cost; it also desalted, clarified, concentrated and purified both E1 and E3. This pioneering study on the separomics and on the a...