Variation in yeast mitochondrial activity associated with asci

An increase in mitochondrial membrane potential (DeltaPsim) and mitochondrially produced 3-hydroxy (3-OH) oxylipins was experienced in asci of the nonfermentative yeasts Galactomyces reessii and Lipomyces starkeyi and the fermentative yeasts Pichia farinosa and Schizosaccharomyces octosporus. Strikingly, asci of Zygosaccharomyces bailii showed no increase in mitochondrial activity (DeltaPsim and oxylipin production). As expected, oxygen deprivation only inhibited ascus formation in those yeasts with increased ascus mitochondrial activity. We conclude that ascus formation in yeasts is not always dependent on mitochondrial activity. In this case, fermentation may provide enough energy for ascus formation in Z. bailii.     

Distribution of 3-hydroxy oxylipins and acetylsalicylic acid sensitivity in Cryptococcus species

Using a well tested antibody specific for 3-hydroxy oxylipins, we mapped the presence of these oxylipins in selected Cryptococcus (Filobasidiella) species. Immunofluorescence microscopy studies revealed that these compounds are deposited on cell wall surfaces, appendages, and collarettes. In vitro studies revealed that growth of Cryptococcus species was inhibited by acetylsalicylic acid (which is known to inhibit mitochondrial function, including the production of 3-hydroxy oxylipins) at concentrations as low as 1 mmol/L. The results suggest that acetylsalicylic acid is effective in controlling the growth of tested pathogens, probably by targeting their mitochondria. This study further expands the known function of this anti-inflammatory drug as anti-fungal agent.     

The development of an ultra performance liquid chromatography-coupled atmospheric pressure chemical ionization mass spectrometry assay for seven adrenal steroids

An ultra performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (UPLC-APCI-MS) method was developed for the separation and quantification of adrenal steroid metabolites from heterologous expression media. Steroids were extracted by liquid-liquid extraction, separated on a Waters UPLC BEH C18 column, ionized by APCI, and detected using a triple quadrupole mass spectrometer in APCI positive mode with single ion monitoring. The incorporation of UPLC enabled the detection of seven structurally closely related steroids at between 5 and 40 ng/ml using run times of 11 min. The adrenal steroidogenic enzyme cytochrome P450 17-hydroxylase/17,20-lyase (CYP17) was expressed in the yeast Pichia pastoris and in nonsteroidogenic COS-1 cells, and used as a model system to evaluate the detection and quantification of adrenal steroid metabolites by UPLC-APCI-MS.     

Individual tree context and contrast dictate tree physiological features and arthropod biodiversity patterns across multiple trophic levels

1. The present study tested the hypothesis that tree context (natural, semi-natural or planted) and contrast (height of surrounding vegetation) affect tree physiological characters (leaf size, nutrient content, and stress-related factors), and also alter the arthropod biodiversity patterns either directly or indirectly. 2. Arthropods were collected from tree canopies using chemical fogging from the ecologically important South African native tree Podocarpus elongatus. 3. Low contrast trees had significantly larger leaves than those in high contrast environments and harboured an overall higher richness, abundance, and biomass of arthropods, although this was guild-dependent. 4. Trees in natural contexts had less foliar δ¹³C, suffered less from artificial nitrogen enrichment, and harboured significantly higher herbivore and predator arthropod richness and unique assemblages, compared with planted trees. 5. Semi-natural trees supported natural levels of arthropod richness, although these were mostly generalist species. 6. Tree context and contrast can therefore dictate associated biota at multiple trophic levels and native trees may fail to maintain natural biodiversity in transformed landscapes.     

The effect of temperature on the individual stages of the hydrolysis of non-specific-p-nitrophenol esters by alpha-chymotrypsin.

Precise studies were performed on the effect of temperature on the rate and equilibrium parameters characterizing the individual stages of the alpha-chymotrypsin-catalysed hydrolysis of non-specific p-nitrophenol esters at pH 7.40 and 8.50. At both pH values the results indicate that a sharp kinetic anomaly is observed in Arrhenius plots of these parameters for the binding and acylation stages of the process, but not for the deacylation stage. Detailed comparison with other kinetic studies was made, and a comparison with thermal transitions observed in alpha-chymotrypsin by using physical techniques was attempted. A detailed discussion of possible causes of the anomalies is given.     

Predicting the distribution of <Emphasis Type="Italic">Encephalartos latifrons</Emphasis>, a critically endangered cycad in South Africa

This study evaluates how a modelling approach to determine areas of suitable habitat for the Critically Endangered Albany cycad Encephalartos latifrons can assist in systematic conservation planning for this and other rare and threatened cycads. A map distinguishing suitable from unsuitable habitat for E. latifrons was produced and important environmental predictors (climate, geology, topography and vegetation) influencing the suitable habitat were estimated. The maximum entropy (MaxEnt) modelling technique was chosen for this study as it has consistently performed well compared with alternative modelling methods and is also an appropriate model choice when the sample size is small and locality records are relatively few. Predicted habitat suitability showed that some locations chosen for translocation and restoration of E. latifrons specimens are not suitable. This revealed that modelling suitable habitat can guide relocation and regeneration of E. latifrons and perhaps other threatened cycads with restricted distributions and few locality records. The species distribution model constructed for E. latifrons is the first reported habitat model for a Critically Endangered cycad in South Africa. The results may be incorporated into conservation planning and structured decision-making about translocations and restoration programmes involving vulnerable cycads, which are among the most threatened organisms globally.     

Studies on the high-sulphur proteins of reduced Merino wool. Amino acid sequence of protein SCMBK-IIIB3

The complete amino acid sequence of wool protein SCMKB-IIIB3 was determined. The peptides used for the sequence work were obtained by peptic and thermolysin digestions and were fractionated by chromatography on DEAE-cellulose, paper chromatography and electrophoresis. The peptides were analysed by dansyl-Edman degradation, mass spectrometry and tritium-labelling of C-terminal residues. The protein consists of 98 residues and has acetylalanine as N-terminal residue and carboxymethylcysteine as C-terminus. It is homologous with protein SCMKB-IIIB2 (Haylett & Swart, 1969). A salient feature of the sequence of protein SCMKB-IIIB3 is three consecutive cysteine residues.     

Charge modification of plasma and milk proteins results in antiviral active compounds.

Previous studies have shown that acylated plasma and milk proteins with increased negative charge, derived from various animal and human sources, are potent anti-HIV compounds. The antiviral effects seemed to correlate positively with the number of negative charges introduced into the various polypeptides: proteins with a high content of basic amino acids in which all of the available epsilonNH2 groups were anionized yielded the most potent anti-HIV compounds. It remained unclear however whether the total net negative charge of the various derivatized proteins, or rather the charge density on the protein backbone, is essential for the observed anti-HIV activity. Earlier studies have shown that acylated albumins preferentially block the process of HIV/cell fusion through binding to the HIV envelope proteins gp120 and gp41 as well as to the cell surface of the HIV target cells. Some of these polyanionic proteins have been shown to interfere also with the gp120-CD4 mediated virus/cell binding. The relative contribution of these effects to the anti-HIV activity may depend both on the total negative charge introduced as well as the hydrophobicity of the acylating reagent added to the particular proteins. In this study we show that the higher the charge density of the derivatized proteins, the more potent their HIV replication inhibiting effects are. In contrast, the addition of positive charge to the studied plasma and milk proteins through amination resulted in a reduced anti-HIV activity but a clearly increased anti-HCMV activity, with IC50 values in the low micromolar concentration range. Interestingly, native lactoferrin (Lf) was antivirally active against both HIV and HCMV. Acylation or amination of Lf increased the anti-HIV and anti-HCMV activity, respectively. The N-terminal portion of Lf appeared essential for its anti-HCMV effect: N-terminal deletion variants of human Lf were less active against HCMV. Circular dichroism of the modified proteins showed that the secondary structure of the tested proteins was only moderately influenced by acylation and/or covalent attachment of drugs, making these (derivatized) proteins useful candidates as antiviral agents and/or intrinsically active drug carriers. The relatively simple chemical derivatization as well as the abundant sources of blood plasma and milk proteins provides attractive opportunities for the preparation of potent and relatively cheap antiviral agents for systemic or local applications.     

Evidence use in decision-making on introducing innovations: a systematic scoping review with stakeholder feedback

Background

A range of evidence informs decision-making on innovation in health care, including formal research findings, local data and professional opinion. However, cultural and organisational factors often prevent the translation of evidence for innovations into practice. In addition to the characteristics of evidence, it is known that processes at the individual level influence its impact on decision-making. Less is known about the ways in which processes at the professional, organisational and local system level shape evidence use and its role in decisions to adopt innovations.

Methods

A systematic scoping review was used to review the health literature on innovations within acute and primary care and map processes at the professional, organisational and local system levels which influence how evidence informs decision-making on innovation. Stakeholder feedback on the themes identified was collected via focus groups to test and develop the findings.

Results

Following database and manual searches, 31 studies reporting primary qualitative data met the inclusion criteria: 24 were of sufficient methodological quality to be included in the thematic analysis. Evidence use in decision-making on innovation is influenced by multi-level processes (professional, organisational, local system) and interactions across these levels. Preferences for evidence vary by professional group and health service setting. Organisations can shape professional behaviour by requiring particular forms of evidence to inform decision-making. Pan-regional organisations shape innovation decision-making at lower levels. Political processes at all levels shape the selection and use of evidence in decision-making.

Conclusions

The synthesis of results from primary qualitative studies found that evidence use in decision-making on innovation is influenced by processes at multiple levels. Interactions between different levels shape evidence use in decision-making (e.g. professional groups and organisations can use local systems to validate evidence and legitimise innovations, while local systems can tailor or frame evidence to influence activity at lower levels). Organisational leaders need to consider whether the environment in which decisions are made values diverse evidence and stakeholder perspectives. Further qualitative research on decision-making practices that highlights how and why different types of evidence come to count during decisions, and tracks the political aspects of decisions about innovation, is needed.