Function and regulation of a steroidogenic CYP450 enzyme in the mitochondrion of Toxoplasma gondii.

As an obligate intracellular parasite, Toxoplasma gondii must import essential nutrients from the host cell into the parasitophorous vacuole. We previously reported that the parasite scavenges cholesterol from host endocytic organelles for incorporation into membranes and storage as cholesteryl esters in lipid droplets. In this study, we have investigated whether Toxoplasma utilizes cholesterol as a precursor for the synthesis of metabolites, such as steroids. In mammalian cells, steroidogenesis occurs in mitochondria and involves membrane-bound type I cytochrome P450 oxidases that are activated through interaction with heme-binding proteins containing a cytochrome b5 domain, such as members of the membrane-associated progesterone receptor (MAPR) family. Our LC-MS targeted lipidomics detect selective classes of hormone steroids in Toxoplasma, with a predominance for anti-inflammatory hydroxypregnenolone species, deoxycorticosterone and dehydroepiandrosterone. The genome of Toxoplasma contains homologs encoding a single type I CYP450 enzyme (we named TgCYP450mt) and a single MAPR (we named TgMAPR). We showed that TgMAPR is a hemoprotein with conserved residues in a heme-binding cytochrome b5 domain. Both TgCYP450 and TgMAPR localize to the mitochondrion and show interactions in in situ proximity ligation assays. Genetic ablation of cyp450mt is not tolerated by Toxoplasma; we therefore engineered a conditional knockout strain and showed that iΔTgCYP450mt parasites exhibit growth impairment in cultured cells. Parasite strains deficient for mapr could be generated; however, ΔTgMAPR parasites suffer from poor global fitness, loss of plasma membrane integrity, aberrant mitochondrial cristae, and an abnormally long S-phase in their cell cycle. Compared to wild-type parasites, iΔTgCYP450mt and ΔTgMAPR lost virulence in mice and metabolomics studies reveal that both mutants have reduced levels of steroids. These observations point to a steroidogenic pathway operational in the mitochondrion of a protozoan that involves an evolutionary conserved TgCYP450mt enzyme and its binding partner TgMAPR.

Host MOSPD2 enrichment at the parasitophorous vacuole membrane varies between Toxoplasma strains and involves complex interactions.

Toxoplasma gondii is an obligate, intracellular parasite. Infection of a cell produces a unique niche for the parasite named the parasitophorous vacuole (PV) initially composed of host plasma membrane invaginated during invasion. The PV and its membrane (parasitophorous vacuole membrane [PVM]) are subsequently decorated with a variety of parasite proteins allowing the parasite to optimally grow in addition to manipulate host processes. Recently, we reported a proximity-labeling screen at the PVM-host interface and identified host endoplasmic reticulum (ER)-resident motile sperm domain-containing protein 2 (MOSPD2) as being enriched at this location. Here we extend these findings in several important respects. First, we show that the extent and pattern of host MOSPD2 association with the PVM differ dramatically in cells infected with different strains of Toxoplasma. Second, in cells infected with Type I RH strain, the MOSPD2 staining is mutually exclusive with regions of the PVM that associate with mitochondria. Third, immunoprecipitation and liquid chromatography tandem mass spectrometry (LC-MS/MS) with epitope-tagged MOSPD2-expressing host cells reveal strong enrichment of several PVM-localized parasite proteins, although none appear to play an essential role in MOSPD2 association. Fourth, most MOSPD2 associating with the PVM is newly translated after infection of the cell and requires the major functional domains of MOSPD2, identified as the CRAL/TRIO domain and tail anchor, although these domains were not sufficient for PVM association. Lastly, ablation of MOSPD2 results in, at most, a modest impact on Toxoplasma growth in vitro. Collectively, these studies provide new insight into the molecular interactions involving MOSPD2 at the dynamic interface between the PVM and the host cytosol. IMPORTANCE Toxoplasma gondii is an intracellular pathogen that lives within a membranous vacuole inside of its host cell. This vacuole is decorated by a variety of parasite proteins that allow it to defend against host attack, acquire nutrients, and interact with the host cell. Recent work identified and validated host proteins enriched at this host-pathogen interface. Here, we follow up on one candidate named MOSPD2 shown to be enriched at the vacuolar membrane and describe it as having a dynamic interaction at this location depending on a variety of factors. Some of these include the presence of host mitochondria, intrinsic domains of the host protein, and whether translation is active. Importantly, we show that MOSPD2 enrichment at the vacuole membrane differs between strains indicating active involvement of the parasite with this phenotype. Altogether, these results shed light on the mechanism and role of protein associations in the host-pathogen interaction.

Toxoplasma gondii scavenges mammalian host organelles through the usurpation of host ESCRT-III and Vps4A.

Intracellular pathogens exploit cellular resources through host cell manipulation. Within its nonfusogenic parasitophorous vacuole (PV), Toxoplasma gondii targets host nutrient-filled organelles and sequesters them into the PV through deep invaginations of the PV membrane (PVM) that ultimately detach from this membrane. Some of these invaginations are generated by an intravacuolar network (IVN) of parasite-derived tubules attached to the PVM. Here, we examined the usurpation of host ESCRT-III and Vps4A by the parasite to create PVM buds and vesicles. CHMP4B associated with the PVM/IVN, and dominant-negative (DN) CHMP4B formed many long PVM invaginations containing CHMP4B filaments. These invaginations were shorter in IVN-deficient parasites, suggesting cooperation between the IVN and ESCRT. In infected cells expressing Vps4A-DN, enlarged intra-PV structures containing host endolysosomes accumulated, reflecting defects in PVM scission. Parasite mutants lacking T. gondii (Tg)GRA14 or TgGRA64, which interact with ESCRT, reduced CHMP4B-DN-induced PVM invaginations and intra-PV host organelles, with greater defects in a double knockout, revealing the exploitation of ESCRT to scavenge host organelles by Toxoplasma.

Dense Granule Protein GRA64 Interacts with Host Cell ESCRT Proteins during Toxoplasma gondii Infection.

The intracellular parasite Toxoplasma gondii adapts to diverse host cell environments within a replicative compartment that is heavily decorated by secreted proteins. In an attempt to identify novel parasite secreted proteins that influence host cell activity, we identified and characterized a transmembrane dense granule protein dubbed GRA64 (TGME49_202620). We found that GRA64 is on the parasitophorous vacuolar membrane (PVM) and is partially exposed to the host cell cytoplasm in both tachyzoite and bradyzoite parasitophorous vacuoles. Using co-immunoprecipitation and proximity-based biotinylation approaches, we demonstrated that GRA64 appears to interact with components of the host endosomal sorting complexes required for transport (ESCRT). Genetic disruption of GRA64 does not affect acute Toxoplasma virulence or encystation in mice, as observed via tissue cyst burdens in mice during chronic infection. However, ultrastructural analysis of Δgra64 tissue cysts using electron tomography revealed enlarged vesicular structures underneath the cyst membrane, suggesting a role for GRA64 in organizing the recruitment of ESCRT proteins and subsequent intracystic vesicle formation. This study uncovers a novel host-parasite interaction that contributes to an emerging paradigm in which specific host ESCRT proteins are recruited to the limiting membranes (PVMs) of tachyzoite and bradyzoite vacuoles formed during acute and chronic Toxoplasma infection. IMPORTANCE Toxoplasma gondii is a widespread foodborne parasite that causes congenital disease and life-threatening complications in immunocompromised individuals. Part of this parasite's success lies in its ability to infect diverse organisms and host cells and to persist as a latent infection within parasite-constructed structures called tissue cysts. In this study, we characterized a protein that is secreted by T. gondii into its parasitophorous vacuole during intracellular infection, which we dub GRA64. On the vacuolar membrane, this protein is exposed to the host cell cytosol and interacts with specific host ESCRT proteins. Parasites lacking the GRA64 protein exhibit ultrastructural changes in tissue cysts during chronic infection. This study lays the foundation for future studies on the mechanics and consequences of host ESCRT-parasite protein interactions.

Toxoplasma gondii's Basal Complex: The Other Apicomplexan Business End Is Multifunctional.

The Apicomplexa are famously named for their apical complex, a constellation of organelles at their apical end dedicated to invasion of their host cells. In contrast, at the other end of the cell, the basal complex (BC) has been overshadowed since it is much less prominent and specific functions were not immediately obvious. However, in the past decade a staggering array of functions have been associated with the BC and strides have been made in understanding its structure. Here, these collective insights are supplemented with new data to provide an overview of the understanding of the BC in Toxoplasma gondii. The emerging picture is that the BC is a dynamic and multifunctional complex, with a series of (putative) functions. The BC has multiple roles in cell division: it is the site where building blocks are added to the cytoskeleton scaffold; it exerts a two-step stretch and constriction mechanism as contractile ring; and it is key in organelle division. Furthermore, the BC has numerous putative roles in 'import', such as the recycling of mother cell remnants, the acquisition of host-derived vesicles, possibly the uptake of lipids derived from the extracellular medium, and the endocytosis of micronemal proteins. The latter process ties the BC to motility, whereas an additional role in motility is conferred by Myosin C. Furthermore, the BC acts on the assembly and/or function of the intravacuolar network, which may directly or indirectly contribute to the establishment of chronic tissue cysts. Here we provide experimental support for molecules acting in several of these processes and identify several new BC proteins critical to maintaining the cytoplasmic bridge between divided parasites. However, the dispensable nature of many BC components leaves many questions unanswered regarding its function. In conclusion, the BC in T. gondii is a dynamic and multifunctional structure at the posterior end of the parasite.

The Rab11-family interacting proteins reveal selective interaction of mammalian recycling endosomes with the Toxoplasma parasitophorous vacuole in a Rab11- and Arf6-dependent manner.

After mammalian cell invasion, the parasite Toxoplasma multiplies in a self-made membrane-bound compartment, the parasitophorous vacuole (PV). We previously showed that Toxoplasma interacts with many host cell organelles, especially from recycling pathways, and sequestrates Rab11A and Rab11B vesicles into the PV. Here, we examine the specificity of host Rab11 vesicle interaction with the PV by focusing on the recruitment of subpopulations of Rab11 vesicles characterized by different effectors, for example, Rab11-family interacting roteins (FIPs) or Arf6. Our quantitative microscopic analysis illustrates the presence of intra-PV vesicles with FIPs from class I (FIP1C, FIP2, FIP5) and class II (FIP3, FIP4) but to various degrees. The intra-PV delivery of vesicles with class I, but not class II, FIPs is dependent on Rab11 binding. Cell depletion of Rab11A results in a significant decrease in intra-PV FIP5, but not FIP3 vesicles. Class II FIPs also bind to Arf6, and we observe vesicles associated with FIP3-Rab11A or FIP3-Arf6 complexes concomitantly within the PV. Abolishing FIP3 binding to both Rab11 and Arf6 reduces the number of intra-PV FIP3 vesicles. These data point to a selective process of mammalian Rab11 vesicle recognition and scavenging mediated by Toxoplasma, suggesting that specific parasite PV proteins may be involved in these processes.

Validation of the P1vital® Faces Set for Use as Stimuli in Tests of Facial Emotion Recognition.

BACKGROUND: Negative bias in facial emotion recognition is a well-established concept in mental disorders such as depression. However, existing face sets of emotion recognition tests may be of limited use in international research, which could benefit from more contemporary and diverse alternatives. Here, we developed and provide initial validation for the P1vital® Affective Faces set (PAFs) as a contemporary alternative to the widely-used Pictures of Facial Affect (PoFA). METHODS: The PAFs was constructed of 133 color photographs of facial expressions of ethnically-diverse trained actors and compared with the PoFA, comprised of 110 black and white photographs of facial expressions of generally Caucasian actors. Sixty-one recruits were asked to classify faces from both sets over six emotions (happy, sad, fear, anger, disgust, surprise) varying in intensity in 10% increments from 0 to 100%. RESULTS: Participants were significantly more accurate in identifying correct emotions viewing faces from the PAFs. In both sets, participants identified happy faces more accurately than fearful faces, were least likely to misclassify facial expressions as happy and most likely to misclassify all emotions at low intensity as neutral. Accuracy in identifying facial expressions improved with increasing emotion intensity for both sets, reaching peaks at 60 and 80% intensity for the PAFs and PoFA, respectively. The study was limited by small sizes and age-range of participants and ethnic diversity of actors. CONCLUSIONS: The PAFs successfully depicted a range of emotional expressions with improved performance over the PoFA and may be used as a contemporary set in facial expression recognition tests.

Quantitative Fluorescence Microscopy for Detecting Mammalian Rab Vesicles within the Parasitophorous Vacuole of the Human Pathogen Toxoplasma gondii.

Fluorescence microscopy and image analysis are powerful techniques to examine the distribution and interactions of different cellular compartments, including mammalian organelles with intravacuolar pathogens. Toxoplasma gondii is an obligate intracellular protozoan parasite that forms a membrane-bound compartment, the parasitophorous vacuole (PV), upon invasion of mammalian cells. From within the PV, the parasite interacts with many host organelles (without fusion), redirects host vesicles decorated with Rab GTPases to the PV, and internalizes many of these nutrient-filled Rab vesicles into the PV. Here, we report a method to distinguish the host Rab vesicles that are exclusively trapped in the Toxoplasma PV from those localized along the edge of the vacuole. Such a discrimination between the two Rab vesicle populations (inside versus outside of the PV) allows the selective characterization of the intra-PV Rab vesicles, for example, number per PV, volume, and distance from the PV centroid, as well as comparisons between wild-type and mutant Toxoplasma.

Chemoprophylaxis vaccination with a Plasmodium liver stage autophagy mutant affords enhanced and long-lasting protection.

Genetically attenuated sporozoite vaccines can elicit long-lasting protection against malaria but pose risks of breakthrough infection. Chemoprophylaxis vaccination (CVac) has proven to be the most effective vaccine strategy against malaria. Here, we demonstrate that a liver stage-specific autophagy mutant of Plasmodium berghei (ATG8 overexpressor), when used as a live vaccine under a CVac regimen, provides superior long-lasting protection, in both inbred and outbred mice, as compared to WT-CVac. Uniquely, the protection elicited by this mutant is predominantly dependent on a CD8+ T-cell response through an IFN-γ-independent mechanism and is associated with a stable population of antigen-experienced CD8+ T cells. Jointly, our findings support the exploitation of liver-stage mutants as vaccines under a CVac protocol. This vaccination strategy is also a powerful model to study the mechanisms of protective immunity and discover new protective antigens.

A single Na+-Pi cotransporter in Toxoplasma plays key roles in phosphate import and control of parasite osmoregulation.

Inorganic ions such as phosphate, are essential nutrients required for a broad spectrum of cellular functions and regulation. During infection, pathogens must obtain inorganic phosphate (Pi) from the host. Despite the essentiality of phosphate for all forms of life, how the intracellular parasite Toxoplasma gondii acquires Pi from the host cell is still unknown. In this study, we demonstrated that Toxoplasma actively internalizes exogenous Pi by exploiting a gradient of Na+ ions to drive Pi uptake across the plasma membrane. The Na+-dependent phosphate transport mechanism is electrogenic and functionally coupled to a cipargarmin sensitive Na+-H+-ATPase. Toxoplasma expresses one transmembrane Pi transporter harboring PHO4 binding domains that typify the PiT Family. This transporter named TgPiT, localizes to the plasma membrane, the inward buds of the endosomal organelles termed VAC, and many cytoplasmic vesicles. Upon Pi limitation in the medium, TgPiT is more abundant at the plasma membrane. We genetically ablated the PiT gene, and ΔTgPiT parasites are impaired in importing Pi and synthesizing polyphosphates. Interestingly, ΔTgPiT parasites accumulate 4-times more acidocalcisomes, storage organelles for phosphate molecules, as compared to parental parasites. In addition, these mutants have a reduced cell volume, enlarged VAC organelles, defects in calcium storage and a slightly alkaline pH. Overall, these mutants exhibit severe growth defects and have reduced acute virulence in mice. In survival mode, ΔTgPiT parasites upregulate several genes, including those encoding enzymes that cleave or transfer phosphate groups from phosphometabolites, transporters and ions exchangers localized to VAC or acidocalcisomes. Taken together, these findings point to a critical role of TgPiT for Pi supply for Toxoplasma and also for protection against osmotic stresses.

Sitting in the driver's seat: Manipulation of mammalian cell Rab GTPase functions by apicomplexan parasites.

Many intracellular microbial pathogens subvert, disrupt or otherwise modulate host membrane trafficking pathways to establish a successful infection. Among them, bacteria that are trapped in a phagosome during mammalian cell invasion, disengage the programmed degradation process by altering the identity of their replicative niche through the exclusion or recruitment of specific Rab GTPases to their vacuole. Many viruses co-opt essential cellular trafficking pathways to perform key steps in their lifecycles. Among protozoan parasites, Apicomplexa are obligate intracellular microbes that invade mammalian cells by creating a unique, nonfusogenic membrane-bound compartment that protects the parasites straightaway from lysosomal degradation. Recent compelling evidence demonstrates that apicomplexan parasites are master manipulators of mammalian Rab GTPase proteins, and benefit or antagonise Rab functions for development within host cells. This review covers the exploitation of mammalian Rab proteins and vesicles by Apicomplexa, focusing on Toxoplasma, Neospora, Plasmodium and Theileria parasites.

Modelling Toxoplasma gondii infection in a 3D cell culture system In Vitro: Comparison with infection in 2D cell monolayers.

Three-dimensional (3D) cell culture models bridge the gap between two-dimensional (2D) monolayer cultures and animal models. Physiologically relevant, 3D culture models have significantly advanced basic cell science and provide unique insights into host-pathogen interactions intrinsically linked to cell morphology. Toxoplasma gondii is an obligate intravacuolar parasite that chronically infects a large portion of the global human population. Our current understanding of Toxoplasma infection is largely based on 2D cell cultures, in which mammalian cells are grown on flat surfaces. However, 2D cell cultures may not recapitulate key conditions of in vivo infections as they introduce artificial pressures and tensions, which may subsequently alter infectious processes that are dependent on spatiality, e.g., invasion, replication and egress. In this study, we adapted a collagen-based 3D cell culture system to reproduce the 3D environment of T. gondii natural infections for investigation of the replication and egress of the parasite from the parasitophorous vacuole. Suspended in the 3D matrix, Toxoplasma-infected VERO cells have round morphology, as opposed to infected VERO cells in 2D monolayers. The doubling time of Toxoplasma in VERO cells within the matrix is comparable to that of parasites cultivated in VERO cell monolayers. In the absence of the pressure of flattened host cells grown in 2D cultures, the parasitophorous vacuole of T. gondii has a globular shape, with intravacuolar parasites distributed radially, forming 3D spherical 'rosette' structures. Parasites egress radially away from the ruptured host cell in 3D matrices, in contrast to Toxoplasma cultivated in 2D monolayer cultures, where the parasites escape perpendicularly from the flat surface below the host cells. These observations demonstrate the utility of collagen matrices for studying parasite modes of infection as these 3D assays more closely mimic in vivo conditions.

Novel Approaches To Kill Toxoplasma gondii by Exploiting the Uncontrolled Uptake of Unsaturated Fatty Acids and Vulnerability to Lipid Storage Inhibition of the Parasite.

Toxoplasma gondii, an obligate intracellular parasite replicating in mammalian cells within a parasitophorous vacuole (PV), is an avid scavenger of lipids retrieved from the host cell. Following lipid uptake, this parasite stores excess lipids in lipid droplets (LD). Here, we examined the lipid storage capacities of Toxoplasma upon supplementation of the culture medium with various fatty acids at physiological concentrations. Supplemental unsaturated fatty acids (oleate [OA], palmitoleate, linoleate) accumulate in large LD and impair parasite replication, whereas saturated fatty acids (palmitate, stearate) neither stimulate LD formation nor impact growth. Examination of parasite growth defects with 0.4 mM OA revealed massive lipid deposits outside LD, indicating enzymatic inadequacies for storing neutral lipids in LD in response to the copious salvage of OA. Toxoplasma exposure to 0.5 mM OA led to irreversible growth arrest and lipid-induced damage, confirming a major disconnect between fatty acid uptake and the parasite's cellular lipid requirements. The importance of neutral lipid synthesis and storage to avoid lipotoxicity was further highlighted by the selective vulnerability of Toxoplasma, both the proliferative and the encysted forms, to subtoxic concentrations of the acyl coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) pharmacological inhibitor T863. T863-treated parasites did not form LD but instead built up large membranous structures within the cytoplasm, which suggests improper channeling and management of the excess lipid. Dual addition of OA and T863 to infected cells intensified the deterioration of the parasite. Overall, our data pinpoint Toxoplasma DGAT as a promising drug target for the treatment of toxoplasmosis that would not incur the risk of toxicity for mammalian cells.

Correction: Hostile intruder: Toxoplasma holds host organelles captive.

[This corrects the article DOI: 10.1371/journal.ppat.1006893.].

The parasite Toxoplasma sequesters diverse Rab host vesicles within an intravacuolar network.

Many intracellular pathogens subvert host membrane trafficking pathways to promote their replication. Toxoplasma multiplies in a membrane-bound parasitophorous vacuole (PV) that interacts with mammalian host organelles and intercepts Golgi Rab vesicles to acquire sphingolipids. The mechanisms of host vesicle internalization and processing within the PV remain undefined. We demonstrate that Toxoplasma sequesters a broad range of Rab vesicles into the PV. Correlative light and electron microscopy analysis of infected cells illustrates that intravacuolar Rab1A vesicles are surrounded by the PV membrane, suggesting a phagocytic-like process for vesicle engulfment. Rab11A vesicles concentrate to an intravacuolar network (IVN), but this is reduced in Δgra2 and Δgra2Δgra6 parasites, suggesting that tubules stabilized by the TgGRA2 and TgGRA6 proteins secreted by the parasite within the PV contribute to host vesicle sequestration. Overexpression of a phospholipase TgLCAT, which is localized to the IVN, results in a decrease in the number of intravacuolar GFP-Rab11A vesicles, suggesting that TgLCAT controls lipolytic degradation of Rab vesicles for cargo release.

Host lipid droplets: An important source of lipids salvaged by the intracellular parasite Toxoplasma gondii.

Toxoplasma is an obligate intracellular parasite that replicates in mammalian cells within a parasitophorous vacuole (PV) that does not fuse with any host organelles. One mechanism developed by the parasite for nutrient acquisition is the attraction of host organelles to the PV. Here, we examined the exploitation of host lipid droplets (LD), ubiquitous fat storage organelles, by Toxoplasma. We show that Toxoplasma replication is reduced in host cells that are depleted of LD, or impaired in TAG lipolysis or fatty acid catabolism. In infected cells, the number of host LD and the expression of host LD-associated genes (ADRP, DGAT2), progressively increase until the onset of parasite replication. Throughout infection, the PV are surrounded by host LD. Toxoplasma is capable of accessing lipids stored in host LD and incorporates these lipids into its own membranes and LD. Exogenous addition of oleic acid stimulates LD biogenesis in the host cell and results in the overaccumulation of neutral lipids in very large LD inside the parasite. To access LD-derived lipids, Toxoplasma intercepts and internalizes within the PV host LD, some of which remaining associated with Rab7, which become wrapped by an intravacuolar network of membranes (IVN). Mutant parasites impaired in IVN formation display diminished capacity of lipid uptake from host LD. Moreover, parasites lacking an IVN-localized phospholipase A2 are less proficient in salvaging lipids from host LD in the PV, suggesting a major contribution of the IVN for host LD processing in the PV and, thus lipid content release. Interestingly, gavage of parasites with lipids unveils, for the first time, the presence in Toxoplasma of endocytic-like structures containing lipidic material originating from the PV lumen. This study highlights the reliance of Toxoplasma on host LD for its intracellular development and the parasite's capability in scavenging neutral lipids from host LD.

Perspectives of Canadian Final-Year Physiotherapy Students on Cardiorespiratory Physiotherapy as a Career Choice.

Purpose: To investigate the opinions of final-year Canadian physiotherapy students of cardiorespiratory physiotherapy (CRP) and the factors influencing their decision about whether to pursue a career in CRP. Methods: A cross-sectional online survey was completed by final-year Master of Science of Physical Therapy students from three of the largest English-speaking physiotherapy schools in Canada. Results: A total of 120 students responded to the survey (overall response rate was 44%). Fifteen students (12.5%) responded that they were extremely or quite interested in specializing in CRP. The most common factors that positively influenced students' decision to consider specializing in CRP were job accessibility, potential salary, and experiences in the area, and the most common factors that negatively influenced their decision were the clinical aspects of the area, their experiences in the area, job accessibility, and the influence of others. The most common factors that positively influenced students' opinion of CRP were their clinical supervisor, educator, or lecturer; their own clinical experience; and evidence in the literature, and the most common factors that negatively influenced their opinion were their own clinical experience and their peers. Conclusion: Strategies focusing on increasing awareness of the role of physiotherapists in the care of patients with cardiorespiratory conditions, exposing students to the positive impact that physiotherapists have in this practice area, and good mentorship experiences may promote the attractiveness of this specialty.

Objectif : enquêter sur les opinions des étudiants canadiens de dernière année en physiothérapie sur la physiothérapie cardiorespiratoire (PCR) et les facteurs influant leur décision de poursuivre une carrière en PCR. Méthodes : une enquête transversale a été réalisée via un sondage en ligne auprès d'étudiants en dernière année de la maîtrise en physiothérapie dans trois des plus grandes écoles de physiothérapie anglophones au Canada. Résultats : un total de 120 étudiants ont répondu au sondage (taux de participation: 44 %). Quinze étudiants (12,5 %) ont répondu être extrêmement ou plutôt intéressés à se spécialiser en PCR. Les principaux facteurs d'influence positive sur la décision de se diriger vers une spécialisation en PCR sont l'accès à l'emploi, le salaire potentiel et les expériences dans le domaine, tandis que les principaux facteurs d'influence négative sont les aspects cliniques, leurs expériences dans le domaine, l'accès à l'emploi et l'influence d'autrui. Les principaux facteurs d'influence positive sur leur opinion de la PCR sont leur superviseur clinique, leur formateur ou leur professeur, leur propre expérience clinique et les preuves dans la littérature, tandis que les principaux facteurs d'influence négative sont leur expérience clinique et leurs pairs. Conclusion : des stratégies visant à sensibiliser les étudiants au rôle des physiothérapeutes dans la prestation des soins aux patients souffrant de problèmes cardiorespiratoires et à exposer les étudiants à la contribution des physiothérapeutes dans ce champ de pratique, ainsi que de bonnes expériences de mentorat pourraient promouvoir l'attrait de cette spécialité.

Virtual reconstruction of the Australopithecus africanus pelvis Sts 65 with implications for obstetrics and locomotion.

Characterizing australopith pelvic morphology has been difficult in part because of limited fossilized pelvic material. Here, we reassess the morphology of an under-studied adult right ilium and pubis (Sts 65) from Member 4 of Sterkfontein, South Africa, and provide a hypothetical digital reconstruction of its overall pelvic morphology. The small size of the pelvis, presence of a preauricular sulcus, and shape of the sciatic notch allow us to agree with past interpretations that Sts 65 likely belonged to a female. The morphology of the iliac pillar, while not as substantial as in Homo, is more robust than in A.L. 288-1 and Sts 14. We created a reconstruction of the pelvis by digitally articulating the Sts 65 right ilium and a mirrored copy of the left ilium with the Sts 14 sacrum in Autodesk Maya. Points along the arcuate line were used to orient the ilia to the sacrum. This reconstruction of the Sts 65 pelvis looks much like a "classic" australopith pelvis, with laterally flared ilia and an inferiorly deflected pubis. An analysis of the obstetric dimensions from our reconstruction shows similarity to other australopiths, a likely transverse or oblique entrance of the neonatal cranium into the pelvic inlet, and a cephalopelvic ratio similar to that found in humans today.

Arm Activity During Daily Life in Individuals With Chronic Obstructive Pulmonary Disease.

PURPOSE: To determine whether individuals with chronic obstructive pulmonary disease (COPD) have decreased arm activity during daily life compared with healthy controls and explore the relationships between arm activity during daily life and arm functional measures in individuals with COPD. METHODS: This was a prospective cross-sectional study that included 30 people with COPD and 14 healthy controls. Subjects attended a single assessment session in which measurements of arm exercise capacity, arm functional performance, self-perception of performance during activities of daily living (ADL), shoulder and elbow flexion force and biceps and triceps thickness were performed. On completion of this session, participants were issued a wrist actigraph and asked to wear the device on the dominant arm for 24 hours for 7 consecutive days. RESULTS: Compared with healthy controls, patients with COPD presented decreased total activity level in daily life (P = .001). When corrected for walking, the level of arm activity did not differ between individuals with COPD and healthy controls (P = .62). No correlations were found between arm activity and arm exercise capacity, arm functional performance, upper limb muscle strength, and self-perception of performance during ADL (r =-0.20 to 0.14; all P ≥ .10). CONCLUSIONS: Arm activity intensity in individuals with COPD did not differ from that of healthy controls when measured by a wrist actigraph. Moreover, arm activity was not associated with other clinical outcomes of arm function. Disability during ADL is multifactorial, and only limited inferences of function can be made from accelerometer data.