Streptococcus thermophilus : to survive, or not to survive the gastrointestinal tract, that is the question!

The probiotic market is increasing world-wide as well as the number of products marketed as probiotics. Among the latter, many products contain Streptococcus thermophilus strains at several dosages. However, the scientific evidence that should support the probiotic status of those S. thermophilus strains is often contradictory. This review analyses the scientific literature aimed to assess the ability of S. thermophilus strains to survive the human gastrointestinal tract by discussing the scientific validity of the methods applied for the bacterial recovery and identification from stool samples. This review highlights that in most of the intervention studies reviewed, the identification of S. thermophilus strains from stools was not carried out with the necessary taxonomic accuracy to avoid their misidentification with Streptococcus salivarius, a common human commensal and a species phylogenetically close to S. thermophilus. Moreover, this review highlights how critical the accurate taxonomic identification of S. thermophilus in metagenomics-based studies can be

Highlight on the Mechanism of Linear Polyamidoamine Degradation in Water

This paper aims at elucidating the degradation mechanism of linear polyamidoamines (PAAs) in water. PAAs are synthesized by the aza-Michael polyaddition of prim-monoamines or bis-sec-amines with bisacrylamides. Many PAAs are water-soluble and warrant potential for biotechnological applications and as flame-retardants. PAAs have long been known to degrade in water at pH 65 7, but their degradation mechanism was never explored in detail. Filling this gap was necessary to assess the suitability of PAAs for the above applications. To this aim, a small library of nine PAAs was expressly synthesized and their degradation mechanism in aqueous solution studied by 1H-NMR in different conditions of pH and temperature. The main degradation mechanism was in all cases the retro-aza-Michael reaction triggered by dilution but, in some cases, hints were detected of concurrent hydrolytic degradation. Most PAAs were stable at pH 4.0; all degraded at pH 7.0 and 9.0. Initially, the degradation rate was faster at pH 9.0 than at pH 7.0, but the percent degradation after 97 days was mostly lower. In most cases, at pH 7.0 the degradation followed first order kinetics. The degradation rates mainly depended on the basicity of the amine monomers. More basic amines acted as better leaving groups

Pérola-da-terra - Eurhizococcus brasiliensis (Hempel) (Hemiptera: Margarodidae) na cultura da videira.

bitstream/item/140429/1/perola-da-terra.pd

Myrmecofauna (Hymenoptera: Formicidae) present in vineyards infested with Eurhizococcus brasiliensis(Hemiptera: Margarodidae) in southern Brazil.

Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae) is among the principal pests of Brazilian vineyards. Establishment and spread of this species in vineyards are associated with ants (Hymenoptera: Formicidae). This study determined the diversity of the ant fauna in E. brasiliensis infested vineyards in Rio Grande do Sul and Santa Catarina, the main grape-producing states in Brazil. Underground pitfall traps baited with a honey–water solution and sardines were used to sample ants in the spring–summer and fall–winter periods. Twenty-eight species of ants were identified in Rio Grande do Sul and 15 in Santa Catarina. Linepithema micans (Forel) (Hymenoptera: Formicidae) was the most requent and abundant species collected in vineyards in both states. Control strategies for ants associated with the spread of E. brasiliensis should focus on L. micans in vineyards. Key Words: survey; ant; soil scale; Linepithema micans A cochonilha de raízes pérola-da-terra Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae) é considerada uma das principais pragas da videira no Brasil. O estabelecimento e a dispersão da espécie nos parreirais estão associados à formigas (Hymenoptera: Formicidae). Neste trabalho, foi determinada a diversidade da fauna de formigas em parreirais infestados com a cochonilha nos Estados do Rio Grande do Sul e Santa Catarina, principais estados produtores de uva do Brasil. Armadilhas “pitfall” subterrâneas iscadas com solução aquosa de mel e sardinha foram colocadas no interior dos vinhedos entre os períodos da primavera/verão e outono/inverno. Vinte e oito espécies de formigas foram identificadas no Rio Grande do Sul e quinze em Santa Catarina. Linepithema micans (Forel) (Hymenoptera: Formicidae) foi a espécie com maior frequência e abundância nos parreirais amostrados em ambos estados amostrados. Estratégias de controle de formigas associadas à dispersão da pérola-da-terra devem ser direcionadas para esta espécie nos vinhedos. Palavras Chave: levantamento; formiga; cochonilha; Linepithema mican

Eficiência de atrativos alimentares na captura de adultos de Anastrepha fraterculus (Wied., 1830) (Diptera: Tephritidae) na cultura da ameixeira (Prunus domestica).

Neste trabalho, foi avaliada a eficiência de atrativos alimentares no monitoramento de adultos de Anastrepha fraterculus na cultura da ameixeira

Mono-dimensional blue native-PAGE and bi-dimensional blue native/urea-PAGE or /SDS-PAGE combined with nLC-ESI-LIT-MS/MS unveil membrane protein heteromeric and homomeric complexes in streptococcus thermophilus

Protein interactions are essential elements for the biological machineries underlying biochemical and physiological mechanisms indispensable for microorganism life. By using mono-dimensional blue native polyacrylamide gel electrophoresis (1D-BN-PAGE), two-dimensional blue native/urea-PAGE (2D-BN/urea-PAGE) and two-dimensional blue native/SDS-PAGE (2D-BN/SDS-PAGE), membrane protein complexes of Streptococcus thermophilus were resolved and visualized. Protein complex and oligomer constituents were then identified by nLC-ESI-LIT-MS/MS. In total, 65 heteromeric and 30 homomeric complexes were observed, which were then associated with 110 non-redundant bacterial proteins. Protein machineries involved in polysaccharide biosynthesis, molecular uptake, energy metabolism, cell division, protein secretion, folding and chaperone activities were highly represented in electrophoretic profiles; a number of homomeric moonlighting proteins were also identified. Information on hypothetical proteins was also derived. Parallel genome sequencing unveiled that the genes coding for the enzymes involved in exopolysaccharide biosynthesis derive from two separate clusters, generally showing high variability between bacterial strains, which contribute to a unique, synchronized and active synthetic module. The approach reported here paves the way for a further functional characterization of these protein complexes and will facilitate future studies on their assembly and composition during various growth conditions and in different mutant backgrounds, with important consequences for biotechnological applications of this bacterium in dairy productions. Biological significance Combined proteomic procedures have been applied to the characterization of heteromultimeric and homomeric protein complexes from the membrane fraction of S. thermophilus. Protein machineries involved in polysaccharide biosynthesis, molecular uptake, energy metabolism, cell division, protein secretion, folding and chaperone activities were identified; information on hypothetical and moonlighting proteins were also derived. This study is original in the lactic bacteria context and maybe considered as preliminary to a deeper functional characterization of the corresponding protein complexes. Due to the large use of S. thermophilus as a starter for dairy productions, the data reported here may facilitate future investigations on protein complex assembly and composition under different experimental conditions or for bacterial strains having specific biotechnological applications

The role of aerodynamic forces in a mathematical model for suspension bridges

In a fish-bone model for suspension bridges studied by us in a previous paper we introduce linear aerodynamic forces. We numerically analyze the role of these forces and we theoretically show that they do not influence the onset of torsional oscillations. This suggests a new explanation for the origin of instability in suspension bridges: it is a combined interaction between structural nonlinearity and aerodynamics and it follows a precise pattern. This gives an answer to a long-standing question about the origin of torsional instability in suspension bridges

Bioecologia, monitoramento e controle da mariposa-oriental na cultura do pessegueiro no Rio Grande do Sul.

Esta circular técnica tem como objetivo disponibilizar informações referentes à bioecologia da mariposa-oriental na cultura do pessegueiro, apresentando as tecnologias para o seu controle no Estado do Rio Grande do Sul.bitstream/item/48524/1/Circular-Tecnica-86.pd

Acompanhamento da eficiência de atrativos alimentares para o monitoramento de Anastrepha fraterculus na cultura da ameixeira.

Neste trabalho, avaliou-se a eficiência de atrativos alimentares na captura de adultos de A. fraterculus em ameixeira no ano agrícola 2013/14 buscando melhorias no sistema de monitoramento dessa praga, uma vez que o atrativo padrão (suco de uva 25%) não tem sido eficiente em identificar sua presença nos pomares, dificultando a tomada de decisão de controle