Factors affecting paramedicine students' learning about evidence-based practice: a phenomenographic study.

Background: Evidence-based practice is an important component of pre-service professional learning in medicine and allied health degrees, including new programmes in paramedicine. Despite substantial interest in this area, there is still a lack of clear understanding of how the skills and understandings needed to develop the capacity to apply evidence-based practice can best be learned. Evidence-based practice is often described as consisting of five steps: ask, acquire, appraise, apply and assess.

Characterisation of cyanobacterial bicarbonate transporters in E. coli shows that SbtA homologs are functional in this heterologous expression system.

Cyanobacterial HCO3(-) transporters BCT1, SbtA and BicA are important components of cyanobacterial CO2-concentration mechanisms. They also show potential in applications aimed at improving photosynthetic rates and yield when expressed in the chloroplasts of C3 crop species. The present study investigated the feasibility of using Escherichia coli to assess function of a range of SbtA and BicA transporters in a heterologous expression system, ultimately for selection of transporters suitable for chloroplast expression.

Topology mapping to characterize cyanobacterial bicarbonate transporters: BicA (SulP/SLC26 family) and SbtA.

This mini-review addresses advances in understanding the transmembrane topologies of two unrelated, single-subunit bicarbonate transporters from cyanobacteria, namely BicA and SbtA. BicA is a Na(+)-dependent bicarbonate transporter that belongs to the SulP/SLC26 family that is widespread in both eukaryotes and prokaryotes. Topology mapping of BicA via the phoA/lacZ fusion reporter method identified 12 transmembrane helices with an unresolved hydrophobic region just beyond helix 8.

The cyanobacterial CCM as a source of genes for improving photosynthetic CO2 fixation in crop species.

Crop yields need to nearly double over the next 35 years to keep pace with projected population growth. Improving photosynthesis, via a range of genetic engineering strategies, has been identified as a promising target for crop improvement with regard to increased photosynthetic yield and better water-use efficiency (WUE). One approach is based on integrating components of the highly efficient CO(2)-concentrating mechanism (CCM) present in cyanobacteria (blue-green algae) into the chloroplasts of key C(3) crop plants, particularly wheat and rice.

Selective modulation of different GABAA receptor isoforms by diazepam and etomidate in hippocampal neurons.

Diazepam modulation of native γ2-containing GABA(A) (γGABA(A)) receptors increases channel conductance by facilitating protein interactions involving the γ2-subunit amphipathic (MA) region, which is found in the cytoplasmic loop between transmembrane domains 3 and 4 (Everitt et al., 2009). However, many drugs, predicted to act on different GABA(A) receptor subtypes, increase channel conductance leading us to hypothesize that conductance variation in GABA(A) receptors may be a general property, mediated by protein interactions involving the cytoplasmic MA stretch of amino acids.

Membrane topology of the cyanobacterial bicarbonate transporter, SbtA, and identification of potential regulatory loops.

The transporter SbtA is a high affinity Na+-dependent HCO3- uptake system present in a majority of cyanobacterial clades. It functions in conjunction with CO2 uptake systems and other HCO3- uptake systems to allow cyanobacteria to accumulate high levels of HCO3- used to support efficient photosynthetic CO2 fixation via the CO2 concentrating mechanism in these species. The phoA/lacZ fusion reporter method was used to determine the membrane topology of the cyanobacterial bicarbonate transporter, SbtA (predicted size of ∼39.

The cyanobacterial bicarbonate transporter BicA: its physiological role and the implications of structural similarities with human SLC26 transporters.

The cyanobacterial Na+-dependent HCO3- transporter BicA is a member of the ubiquitous and important SulP/SLC26 family of anion transporters found in eukaryotes and prokaryotes. BicA is an important component of the cyanobacterial CO2 concentrating mechanism, an adaptation that contributes to cyanobacteria being able to achieve an estimated 25% of global primary productivity, largely in the oceans. The human SLC26 members are involved in a range of key cellular functions involving a diverse range of anion transport activities including Cl-/HCO3-, I-/HCO3-, and SO42-/HCO3- exchange; mutations in SLC26 members are known to be associated with debilitating diseases such as Pendred syndrome, chondrodysplasias, and congenital chloride diarrhoea.

Characterisation of HvALMT1 function in transgenic barley plants.

HvALMT1 from barley (Hordeum vulgare L.) encodes a protein capable of facilitating the transport of malate and other organic anions when expressed in Xenopus oocytes. The HvALMT1 gene is primarily expressed in guard cells of stomata, in regions behind the root apex and at lateral root junctions.

An acid-loading chloride transport pathway in the intraerythrocytic malaria parasite, Plasmodium falciparum.

The intraerythrocytic malaria parasite exerts tight control over its ionic composition. In this study, a combination of fluorescent ion indicators and (36)Cl(-) flux measurements was used to investigate the transport of Cl(-) and the Cl(-)-dependent transport of "H(+)-equivalents" in mature (trophozoite stage) parasites, isolated from their host erythrocytes. Removal of extracellular Cl(-), resulting in an outward [Cl(-)] gradient, gave rise to a cytosolic alkalinization (i.

HvALMT1 from barley is involved in the transport of organic anions.

Members of the ALMT gene family contribute to the Al(3+) resistance of several plant species by facilitating malate efflux from root cells. The first member of this family to be cloned and characterized, TaALMT1, is responsible for most of the natural variation of Al(3+) resistance in wheat. The current study describes the isolation and characterization of HvALMT1, the barley gene with the greatest sequence similarity to TaALMT1.

Identification and functional characterisation of aquaporins in the grapevine, Vitis vinifera.

Plant aquaporins belong to a large superfamily of conserved proteins called the major intrinsic proteins (MIPs). There is limited information about the diversity of MIPs in grapevine, and their water transport capacity. The aim of the present study was to identify MIPs from grapevine and functionally characterise water transport of a subset of MIPs.

Membrane topology of the cyanobacterial bicarbonate transporter, BicA, a member of the SulP (SLC26A) family.

We have completed the first comprehensive transmembrane topology determination for a member of the ubiquitous and important SulP/SLC26 family of coupled anion transporters found in eukaryotes and prokaryotes. The prokaryotic member that we have mapped, namely BicA from Synechococcus PCC7002, is an important Na(+)-dependent bicarbonate transporter that is likely to play a major role in global primary productivity via the CO(2) concentrating mechanism in cyanobacteria. We experimentally determined the topology based on phoA-lacZ topology mapping combined with reference to a range of predictive models based on hydropathy analysis and positive charge distribution.

Chloroquine transport via the malaria parasite's chloroquine resistance transporter.

The emergence and spread of chloroquine-resistant Plasmodium falciparum malaria parasites has been a disaster for world health. Resistance is conferred by mutations in the Chloroquine Resistance Transporter (PfCRT), an integral membrane protein localized to the parasite's internal digestive vacuole. These mutations result in a marked reduction in the accumulation of chloroquine (CQ) by the parasite.

Purine uptake in Plasmodium: transport versus metabolism.

In a recent paper, Quashie et al. have proposed that purine uptake into the intraerythrocytic malaria parasite involves four different plasma membrane transporters - two high affinity and two low affinity. They equate one of the two high-affinity transporters with PfNT1, a transporter reported previously to be a low-affinity system.

Polar residues in a conserved motif spanning helices 1 and 2 are functionally important in the SulP transporter family.

The SulP family (including the SLC26 family) is a diverse family of anion transporters found in all domains of life, with different members transporting different anions. We used sequence and bioinformatics analysis of helices 1 and 2 of SulP family members to identify a conserved motif, extending the previously defined 'sulfate transporter motif'. The analysis showed that in addition to being highly conserved in both sequence and spacing, helices 1 and 2 contain a significant number of polar residues and are predicted to be buried within the protein interior, with at least some faces packed closely against other helices.

Localisation of a candidate anion transporter to the surface of the malaria parasite.

PfSulP, encoded by the human malaria parasite Plasmodium falciparum, is a member of the sulphate permease family of anion transporter proteins. By transfecting the parasite with an epitope-tagged version of PfSulP, and detecting via western blot and indirect immunofluorescent assay microscopy, we show that PfSulP is localised to the surface of the intraerythrocytic parasite, where it is postulated to play a role in the flux of anions across the parasite plasma membrane.

Purine nucleobase transport in the intraerythrocytic malaria parasite.

Hypoxanthine, a nucleobase, serves as the major source of the essential purine group for the intraerythrocytic malaria parasite. In this study we have measured the uptake of hypoxanthine, and that of the related purine nucleobase adenine, by mature blood-stage Plasmodium falciparum parasites isolated from their host cells by saponin-permeabilisation of the erythrocyte and parasitophorous vacuole membranes. The uptake of both [3H]hypoxanthine and [3H]adenine was comprised of at least two components; in each case there was a rapid equilibration of the radiolabel between the intra- and extracellular solutions via a low-affinity transport mechanism, and an accumulation of radiolabel (such that the estimated intracellular concentration exceeded the extracellular concentration) via a higher-affinity process.

Investigation of the properties of wild type and mutant alkaline phosphatase variants: A laboratory project linking genotype and phenotype.

An understanding of the link between genotype and phenotype is essential for biology students. A 3-wk laboratory project aimed at demonstrating this link and introducing early year students to some aspects of the research process is described. Students investigate the properties of wild type and mutant variants of alkaline phosphatase using the techniques of both biochemistry and molecular biology.

Transport of nucleosides across the Plasmodium falciparum parasite plasma membrane has characteristics of PfENT1.

Like all parasitic protozoa, the human malaria parasite Plasmodium falciparum lacks the enzymes required for de novo synthesis of purines and it is therefore reliant upon the salvage of these compounds from the external environment. P. falciparum equilibrative nucleoside transporter 1 (PfENT1) is a nucleoside transporter that has been localized to the plasma membrane of the intraerythrocytic form of the parasite.

The role of cysteine residues in the sulphate transporter, SHST1: construction of a functional cysteine-less transporter.

We investigated the role of cysteine residues in the sulphate transporter, SHST1, with the aim of generating a functional cysteine-less variant. SHST1 contains five cysteine residues and none was essential for function. However, replacement of C421 resulted in a reduction in transport activity.

Identification of a SulP-type bicarbonate transporter in marine cyanobacteria.

Cyanobacteria possess a highly effective CO(2)-concentrating mechanism that elevates CO(2) concentrations around the primary carboxylase, Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase). This CO(2)-concentrating mechanism incorporates light-dependent, active uptake systems for CO(2) and HCO(-)(3). Through mutant studies in a coastal marine cyanobacterium, Synechococcus sp.

Interactions between charged amino acid residues within transmembrane helices in the sulfate transporter SHST1.

The aim of this study was to identify charged amino acid residues important for activity of the sulfate transporter SHST1. We mutated 10 charged amino acids in or near proposed transmembrane helices and expressed the resulting mutants in a sulfate transport-deficient yeast strain. Mutations affecting four residues resulted in a complete loss of sulfate transport; these residues were D107 and D122 in helix 1 and R354 and E366 in helix 8.

Structure and function of a model member of the SulP transporter family.

SHST1 is a sulfate transporter that belongs to a large and diverse family of anion transporters. Little is known about the structure and function of any member of the family. Site-directed mutagenesis of SHST1 is being used to understand the function of particular amino acids.