The emergence of new infections and increase of bacteria drug-resistance rise up the urgent need for the development of new antibacterial agents from natural sources. This study was designed to evaluate the antibacterial activity of the crude methanolic extract (CME) and fractions [hexane (H), dichloromethane (DCM), ethyl acetate (EA) and ethanol (Et)] obtained from Larrea tridentata (Sessé & Moc. Ex DC.) Coville leaves. The antibacterial activity was determined by the agar diffusion method against six strains of Gram-positive and Gram-negative bacteria. The micro-dilution method was applied for the determination of the minimal inhibitory concentration (MIC) of selected bacteria strains. HPLC analyses of tested samples were also carried out. The antibacterial activity of the samples was more effective inhibiting the growth of Gram-positive bacteria comparing with Gram-negative bacteria, mainly for the CME, DCM and EA fractions. EA fraction showed the highest antibacterial activity against methicillin-resistant Staphylococcus aureus isolated from secretion; with a MIC value (31.3 g/mL) lower than the reference antibiotic tetracycline (64 g/mL). Low MIC values (62.5 g/mL) were also obtained for the CME and DCM fraction. CME and EA fraction presented the highest concentrations of quercetin, kaempferol and nordihydroguaiaretic acid. These compounds have important biological activities and could be responsible for at least part of the antibacterial activity of the CME, DCM and EA fractions. EA fraction from L. tridentata leaves was the most efficient to inhibit the growth of the bacterial strain methicillin-resistant S. aureus, which represents an important step for the search and development of a new antibacterial agent.

The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000 µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities.

Antimicrobial activities of "babaçu" (Orbignya martiana), "cardo santo" (Argemone mexicana), "mentrasto" (Ageratum conyzoides), "cavalinha" (Equisetum yeamalis) and "terramicina" (Alternanthera brasiliana), used by Brazilian population as antiinflamatory medicine, were studied on Staphylococcus aureus. The freezer dried hydroalcoholic extracts solutions were tested for 7 strains of Staphylococcus aureus, which two of those are methicillin resistant (MRSA). The diffusion method on agar-agar, using holes technique, with tetracycline chlorydrate as standard. "Babaçu", "cardo santo" and "terramicina" showed antimicrobial activity, within of those "terramicina" inhibited 6 strains, presenting zone inhibition of 22 mm compared to standard antibiotic (34 mm), except the seventh strain which was also tetracycline resistant.A WHO considerou que no mundo aproximadamente 80% de uma população de 4 bilhões dependem principalmente da medicina tradicional para seus cuidados primários de saúde, bem a partir, do uso de extratos de plantas ou de seus princípios ativos 1,2,7 . Assim serão determinadas a atividade antimicrobiana das plantas babaçu (Orbignya martiana), cardo santo (Argemone mexicana), mentrasto (Ageratum conyzoides), cavalinha (Equisetum yeamalis) e terramicina (Alternanthera brasiliana) frente as cepas de Staphylococcus aureus. Material e MétodosAs cepas de Staphylococcus aureus usadas no teste são apresentadas na tabela 1. No estudo são retidas duas cepas padrões (ATCC) de reconhecida resistência, utilizadas nos testes para conservantes e desinfetantes, cinco isolados hospitalares: três meticilina sensível e dois meticilina resistente.As plantas com seus extratos são apresentados na tabela 2, todos os testes foram realizados com extratos aquosos obtidos a partir de liofilizados de extratos hidroalcóolicos (1:1) das referidas plantas.No caso da Alternanthera brasiliana (terramicina) o extrato tinha uma consistência mais pastosa, que dificultou a pesada.A metodologia empregada foi a técnica de discos por difusão em ágar e a técnica de poços por difusão em ágar, utilizando-se como antibiótico padrão: cloridrato de tetraciclina (solução mãe 1 mg/ml) e como meio ágar Müeller Hinton semeado na superfície com os inóculos bacterianos. O uso de dois ou mais métodos para o estudo da atividade antimicrobiana permite obter melhores resultados 9 . As placas foram deixadas em repouso por 40 min à temperatura ambiente antes de incubar (tempo de predifusão).

Human adipose stem/stromal cell (ASC) spheroids were used as a serum‐free in vitro model to recapitulate the molecular events and extracellular matrix organization that orchestrate a hypertrophic cartilage phenotype. Induced‐ASC spheroids (ø = 450 µm) showed high cell viability throughout the period of culture. The expression of collagen type X alpha 1 chain (COLXA1) and matrix metallopeptidase 13 (MMP‐13) was upregulated at week 2 in induced‐ASC spheroids compared with week 5 (P < .001) evaluated by quantitative real‐time PCR. In accordance, secreted levels of IL‐6 (P < .0001), IL‐8 (P < .0001), IL‐10 (P < .0001), bFGF (P < .001), VEGF (P < .0001), and RANTES (P < .0001) were the highest at week 2. Strong in situ staining for collagen type X and low staining for TSP‐1 was associated with the increase of hypertrophic genes expression at week 2 in induced‐ASC spheroids. Collagen type I, osteocalcin, biglycan, and tenascin C were detected at week 5 by in situ staining, in accordance with the highest expression of alkaline phosphatase (ALPL) gene and the presence of calcium deposits as evaluated by Alizarin Red O staining. Induced‐ASC spheroids showed a higher force required to compression at week 2 (P < .0001). The human ASC spheroids under serum‐free inducer medium and normoxic culture conditions were induced to a hypertrophic cartilage phenotype, opening a new perspective to recapitulate endochondral ossification in vivo.

The genome data of bacterium Xylella fastidiosa strain 9a5c has identified several orfs related to its phytopathogenic adaptation and survival. Among these genes, the surE codifies a survival protein E (XfSurE) whose function is not so well understood, but functional assays in Escherichia coli revealed nucleotidase and exopolyphosphate activity. In the present study, we report the XfSurE protein overexpression in E. coli and its purification. The overall secondary structure was analyzed by CD. Small‐angle X‐ray scattering and gel filtration techniques demonstrated that the oligomeric state of the protein in solution is a tetramer. In addition, functional kinetics experiments were carried out with several monophosphate nucleoside substrates and revealed a highly positive cooperativity. An allosteric mechanism involving torsion movements in solution is proposed to explain the cooperative behaviour of XfSurE. This is the first characterization of a SurE enzyme from a phytopathogen organism and, to our knowledge, the first solution structure of a SurE protein to be described. Structured digital abstract http://mint.bio.uniroma2.it/mint/search/interaction.do?interactionAc=MINT-7262492: XfSurE (uniprotkb:http://www.ebi.uniprot.org/entry/Q9PF20) and XfSurE (uniprotkb:http://www.ebi.uniprot.org/entry/Q9PF20) bind (http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0407) by x ray scattering (http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0826) http://mint.bio.uniroma2.it/mint/search/interaction.do?interactionAc=MINT-7262504: XfSurE (uniprotkb:http://www.ebi.uniprot.org/entry/Q9PF20) and XfSurE (uniprotkb:http://www.ebi.uniprot.org/entry/Q9PF20) bind (http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0407) by molecular sieving (http://www.ebi.ac.uk/ontology-lookup/?termId=MI:0071)