297 research outputs found
Microsecond folding dynamics of the F13W G29A mutant of the B domain of staphylococcal protein A by laser-induced temperature jump
The small size (58 residues) and simple structure of the B domain of staphylococcal protein A (BdpA) have led to this domain being a paradigm for theoretical studies of folding. Experimental studies of the folding of BdpA have been limited by the rapidity of its folding kinetics. We report the folding kinetics of a fluorescent mutant of BdpA (G29A F13W), named F13W*, using nanosecond laser-induced temperature jump experiments. Automation of the apparatus has permitted large data sets to be acquired that provide excellent signal-to-noise ratio over a wide range of experimental conditions. By measuring the temperature and denaturant dependence of equilibrium and kinetic data for F13W*, we show that thermodynamic modeling of multidimensional equilibrium and kinetic surfaces is a robust method that allows reliable extrapolation of rate constants to regions of the folding landscape not directly accessible experimentally. The results reveal that F13W* is the fastest-folding protein of its size studied to date, with a maximum folding rate constant at 0 M guanidinium chloride and 45°C of 249,000 (s-1). Assuming the single-exponential kinetics represent barrier-limited folding, these data limit the value for the preexponential factor for folding of this protein to at least â2 x 10(6) s(-1)
Are 'New' Donors Different? Comparing the Allocation of Bilateral Aid Between Non-DAC and DAC Donor Countries
Below the Belt? Territory and Development in Chinaâs International Rise
Chinaâs internationalization has been heralded by some as a new era of SouthâSouth cooperation. Yet such framings of development are pitched at an abstract space of the âglobal Southâ which conceals more than it reveals. With some theory moving towards ontologies of âglobal developmentâ, we need to capture both the connectedness and the local specificity of increasingly diffuse processes. This article sets out a more fine-grained understanding of how political territories and processes are imagined and produced by and through Chinaâs internationalization, focusing on infrastructure as a âtechnologyâ of territorialization. Much of the focus on Chinaâs internationalization has been on state-to-state relations, but this obscures the âomni-channel politicsâ that China practises. Using a critical literature review and illustrative case study, this article develops the idea of omni-channel politics to posit a view of âtwistedâ territories in which political processes and development outcomes are more complex and contingent
The DanTIN project â creating a platform for describing the grammar of Danish talk-in-interaction
The article introduces a new website, samtalegrammatik.dk ('grammar of
talk-in-interaction'), it describes the methods used for constructing the
website, and it provides descriptions of three new grammatical phenomena
in Danish talk-in-interaction. The website is a result of investigations carried
out by the research group DanTIN ('Danish talk-in-interaction') since
2009. Until 2013, the group has published analyses of quite diverse phenomena,
such as different versions of the word hvad 'what' that seem to belong
to different word classes and have different functions in talk-ininteraction,
the distribution of the hesitation marker øh(m) 'uh(m)', or different
word orders after the conjunction fordi ('because'). These phenomena
were selected because they were clearly different from written Danish.
By launching the website samtalegrammatik.dk the group takes a step towards
building a comprehensive grammar of Danish talk-in-interaction. It
offers a template for a description of all aspects of the grammar of Danish
talk-in-interaction, even though at the time of the launching only a little
part of the entries will be filled in. The idea is that the investigations will be
continued in many years to come, and, thus, the website will grow and become
more complete. The three phenomena reported in some detail here all
have intonation as an important part of their grammatical descriptions.
They are (1) the particle nĂĽ (roughly 'oh'), (2) exaggerated pitch as a story
ending device, and (3) the interjection ej, which is an intranslatable exclamation
word. FGW â Publications without University Leiden contrac
Comparison between mixed liquors of two side-stream membrane bioreactors treating wastewaters from waste management plants with high and low solids anaerobic digestion
In the last years, biological treatment plants for the previously separated organic fraction from municipal solid wastes (OFMSW) have gained importance. In these processes a liquid effluent (liquid fraction from the digestate and leachate from composting piles), which has to be treated previously to its discharge, is produced. In this paper, the characteristics of the mixed liquor from two full-scale membrane bioreactors treating the effluents of two OFMSW treatment plants have been evaluated in view to study their influence on membrane fouling in terms of filterability. For that, the mixed liquor samples have been ultrafiltrated in an OF laboratory plant. Besides, the effect of the influent characteristics to MBRs and the values of the chemical and physical parameters of the mixed liquors on the filterability have been studied. Results showed that the filterability of the mixed liquor was strongly influenced by the soluble microbial products in the mixed liquors and the influent characteristics to MBR. Permeate flux of MBR mixed liquor treating the most polluted wastewater was considerable the lowest (around 20 L/m(2) h for some samples), what was explained by viscosity and soluble microbial products concentration higher than those measured in other MBR mixed liquor. (c) 2016 Elsevier Ltd. All rights reserved.This work was supported by the URBASER Company. Authors thank personnel of the full-scale MBR plants for providing samples.Zuriaga Agusti, E.; Mendoza Roca, JA.; Bes PiĂĄ, MA.; Alonso Molina, JL.; FernĂĄndez-GimĂŠnez, E.; Alvarez-Requena, C.; Munagorri-Manueco, F.... (2016). Comparison between mixed liquors of two side-stream membrane bioreactors treating wastewaters from waste management plants with high and low solids anaerobic digestion. Water Research. 100:517-525. doi:10.1016/j.watres.2016.05.053S51752510
Study of 16 Portuguese activated sludge systems based on filamentous bacteria populations and their relationships with environmental parameters
A survey in 16 activated sludge waste water treatment plants (WWTP) was conducted to contribute to the knowledge of the environmental parameters that determine the composition of the filamentous community. A total of 128 samples of mixed liquor from municipal WWTP were collected during 2 years, and 22 filamentous morphotypes were identified. The most frequent and abundant filamentous bacteria were, in both cases and by this order, type 0041/0675, type 0092, Microthrix parvicella and 1851, nocardioforms and Haliscomenobacter hydrossis. Concerning dominance, type 1851 was the most frequently dominant morphotype, followed by M. parvicella and types 0092 and 0041/0675. These were also, and by this order, the dominant morphotypes during bulking occurrences. Significant correlations were obtained between the abundance of filamentous bacteria and environmental parameters, but multivariate statistical analysis only confirmed the correlation between type 0092 and Sludge Volume Index (SVI), emphasizing the association of this filament with bulking. The discussion of the results in light of published works was complicated by the random use of terms such as frequency, abundance, and dominance with different and often unclear meanings. This reinforces the need of clarifying these terms when discussing the causes of filamentous overgrowth in WWTP.Portuguese Foundation for Science and Technology (FCT) and the European Community fund FEDER, through Program COMPETE, in the ambit of the Projects
FCOMP-01-0124-FEDER-007025 (PTDC/AMB/68393/2006), PEst-OE/EQB/LA0023/2013, RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), and the Project BBioEnv - Biotechnology and
Bioengineering for a sustainable world,REF. NORTE-07-0124-
FEDER-000048, co-funded by the Programa Operacional Regional do
Norte (ON.2 â O Novo Norte), QREN, FEDER. PhD grant SFRH/BD/64848/200
β-Microseminoprotein Endows Post Coital Seminal Plasma with Potent Candidacidal Activity by a Calcium- and pH-Dependent Mechanism
The innate immune factors controlling Candida albicans are mostly unknown. Vulvovaginal candidiasis is common in women and affects approximately 70â75% of all women at least once. Despite the propensity of Candida to colonize the vagina, transmission of Candida albicans following sexual intercourse is very rare. This prompted us to investigate whether the post coital vaginal milieu contained factors active against C. albicans. By CFU assays, we found prominent candidacidal activity of post coital seminal plasma at both neutral and the acid vaginal pH. In contrast, normal seminal plasma did not display candidacidal activity prior to acidification. By antifungal gel overlay assay, one clearing zone corresponding to a protein band was found in both post coital and normal seminal plasma, which was subsequently identified as β-microseminoprotein. At neutral pH, the fungicidal activity of β-microseminoprotein and seminal plasma was inhibited by calcium. By NMR spectroscopy, amino acid residue E71 was shown to be critical for the calcium coordination. The acidic vaginal milieu unleashed the fungicidal activity by decreasing the inhibitory effect of calcium. The candidacidal activity of β-microseminoprotein was mapped to a fragment of the C-terminal domain with no structural similarity to other known proteins. A homologous fragment from porcine β-microseminoprotein demonstrated calcium-dependent fungicidal activity in a CFU assay, suggesting this may be a common feature for members of the β-microseminoprotein family. By electron microscopy, β-microseminoprotein was found to cause lysis of Candida. Liposome experiments demonstrated that β-microseminoprotein was active towards ergosterol-containing liposomes that mimic fungal membranes, offering an explanation for the selectivity against fungi. These data identify β-microseminoprotein as an important innate immune factor active against C. albicans and may help explain the low sexual transmission rate of Candida
Comparative antibacterial potential of selected aldehyde-based biocides and surfactants against planktonic Pseudomonas fluorescens
The antimicrobial efficacy of two aldehydebased biocides (glutaraldehyde, GTA, and orthophthalaldehyde, OPA) and two surfactants (cetyltrimethyl ammonium bromide, CTAB, and sodium dodecyl sulphate,
SDS) was tested against planktonic Pseudomonas fluorescens. The antimicrobial effects were evaluated by respiratory activity as a measure of the oxygen uptake
rate, adenosine triphosphate (ATP) release, outer membrane proteins (OMP) expression and cellular colour changes. The results were compared with the bacterial
characteristics without chemical treatment. Tests in the presence of bovine serum albumin (BSA), in order to mimic a disinfection process in the real situation under dirty conditions, were performed according to the
European Standard EN-1276. P. fluorescens was completely inactivated with OPA (minimum bactericidal concentration, MBC = 0.5 mM) and CTAB (MBC = 5 mM) and was resistant to GTA and SDS. Only CTAB promoted cellular disruption and consequent
ATP release. The antimicrobial action of the
chemicals tested was significantly reduced when BSA was introduced into the bacterial cultures, increasing markedly the MBC values. Additionally, the presence of BSA
acted as a disruption protective agent when CTAB was applied and stimulated the bacterial respiratory activity when lower concentrations of SDS were tested. The
OMP of the bacterial cells was affected by the application of both surfactants. OMP expression remained unaltered after biocide treatment. Bacterial colour change was
noticed after treatment with biocides and surfactants. In summary, P. fluorescens was extremely resistant to GTA and SDS, with antimicrobial action being quenched
markedly by the reaction with BSA.Instituto de Biotecnologia e QuĂmica Fina (IBQF).Fundação para a CiĂŞncia e a Tecnologia (FCT) - (Project CHEMBIO - POCI/BIO/61872/2004
Comparison of the bacterial community composition in the granular and the suspended phase of sequencing batch reactors
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