The proteasome cap RPT5/Rpt5p subunit prevents aggregation of unfolded ricin A chain.

The plant cytotoxin ricin enters mammalian cells by receptor-mediated endocytosis, undergoing retrograde transport to the ER (endoplasmic reticulum) where its catalytic A chain (RTA) is reductively separated from the holotoxin to enter the cytosol and inactivate ribosomes. The currently accepted model is that the bulk of ER-dislocated RTA is degraded by proteasomes. We show in the present study that the proteasome has a more complex role in ricin intoxication than previously recognized, that the previously reported increase in sensitivity of mammalian cells to ricin in the presence of proteasome inhibitors simply reflects toxicity of the inhibitors themselves, and that RTA is a very poor substrate for proteasomal degradation. Denatured RTA and casein compete for a binding site on the regulatory particle of the 26S proteasome, but their fates differ. Casein is degraded, but the mammalian 26S proteasome AAA (ATPase associated with various cellular activities)-ATPase subunit RPT5 acts as a chaperone that prevents aggregation of denatured RTA and stimulates recovery of catalytic RTA activity in vitro. Furthermore, in vivo, the ATPase activity of Rpt5p is required for maximal toxicity of RTA dislocated from the Saccharomyces cerevisiae ER. The results of the present study implicate RPT5/Rpt5p in the triage of substrates in which either activation (folding) or inactivation (degradation) pathways may be initiated.

Mental health in the two years following hypertensive and normotensive pregnancy: The Postpartum, Physiology, Psychology and Paediatric follow-up (P4) cohort study.

BACKGROUND: Postpartum mental illnesses and hypertensive disorders of pregnancy (HDP) are both common, and both associated with adverse maternal and child health outcomes. However, the relationship between them is unclear. This study aimed to investigate prevalence and symptom severity of depression, anxiety, and post-traumatic stress disorder (PTSD) 2-years postpartum in women with normal blood pressure (NBP) during pregnancy versus preeclampsia or gestational hypertension (GH). METHODS: Two-years follow-up of the prospective Postpartum, Physiology, Psychology and Paediatric (P4) Cohort Study was conducted in metropolitan Australia. Prevalence and symptom severity of depression (Edinburgh Postnatal Depression Scale, EPDS > 12), anxiety (7-item Generalized Anxiety Disorder scale, GAD-7 ≥ 10) and PTSD (Posttraumatic stress Diagnostic Scale, PDS/PDS-5) were measured and calculated for women with NBP, preeclampsia and GH. RESULTS: Among 365 participants (NBP: n = 271, preeclampsia: n = 75, GH: n = 19), 2-years postpartum depression prevalence was 3.9% (95% CI 2.3-6.4%): 4.4% after NBP, and 2.7% after preeclampsia (p = 0.53). Anxiety prevalence was higher after GH than NBP (15.8% versus 3.3%, p = 0.02). Prevalence of any mental illness (depression/anxiety/PTSD) was 5.9% (95% CI 3.8-8.8%); 5.6% after NBP, 4.1% after PE, and 15.8% after GH (p = 0.15). Although PTSD prevalence was low (1.4%), and similar between groups (p = 0.97), around 3 times more women after PE (8.1%), compared to NBP (2.5%), recalled childbirth as traumatic (p = 0.003). CONCLUSIONS: Preeclampsia, although associated with persistent perceptions of traumatic childbirth, did not alter the risk of mental illnesses at 2-years postpartum. GH (albeit in a small subgroup) was associated with increased anxiety scores. Larger, multicentre studies are required to clarify relationships between HDP and postpartum mental illness. TRIAL REGISTRATION: Retrospectively registered on 18/11/2013 with the Australian and New Zealand Clinical Trials Registry. REGISTRATION NUMBER: ACTRN 12613 00,126 0718.

Preeclampsia-Associated Cardiovascular Risk Factors 6 Months and 2 Years After Pregnancy: The P4 Study.

BACKGROUND: Increased cardiovascular risk following preeclampsia is well established and there are signs of early cardiovascular aging 6 months postpartum. This study assessed whether blood pressure (BP) and other cardiovascular measures are abnormal 2 years postpartum in the same cohort to determine ongoing risk markers. METHODS: Six months and 2 years postpartum, BP was measured using sphygmomanometry, 24-hour ambulatory BP monitoring, and noninvasive central BP. Anthropometric measures, blood, and urine biochemistry were performed. Cross-sectional comparisons between preeclampsia and normotensive pregnancy (NP) groups and longitudinal comparisons within each group were made at 6 months and 2 years. RESULTS: Two years postpartum, 129 NP, and 52 preeclampsia women were studied who also had 6 months measures. At both time points, preeclampsia group had significantly higher BP (office BP 2 years, 112±12/72±8 versus 104±9/67±7 mm Hg NP; [P<0.001]; mean ambulatory BP monitoring 116±9/73±8 versus 106±8/67±6 mm Hg NP; [P<0.001]). No significant BP changes noted 6 months to 2 years within either group. Office BP thresholds of 140 mm Hg systolic and 90 mm Hg diastolic classified 2% preeclampsia and 0% NP at 2 years. American Heart Association 2017 criteria (above normal, >120/80 mm Hg) classified 25% versus 8% (P<0.002), as did our reference range threshold of 122/79 mm Hg. American Heart Association criteria classified 60% post-preeclampsia versus 16% after NP with above-normal ambulatory BP monitoring (P<0.001). Other cardiovascular risk markers more common 2 years post-preeclampsia included higher body mass index (median 26.6 versus 23.1, P=0.003) and insulin resistance. CONCLUSIONS: After preeclampsia, women have significantly higher BP 6 months and 2 years postpartum, and have higher body mass index and insulin-resistance scores, increasing their future cardiovascular risk. Regular cardiovascular risk screening should be implemented for all who have experienced preeclampsia.

An Exo2 derivative affects ER and Golgi morphology and vacuolar sorting in a tissue-specific manner in arabidopsis.

We screened a panel of compounds derived from Exo2 - a drug that perturbs post-Golgi compartments and trafficking in mammalian cells - for their effect on the secretory pathway in Arabidopsis root epidermal cells. While Exo2 and most related compounds had no significant effect, one Exo2 derivative, named LG8, induced severe morphological alterations in both the Golgi (at high concentrations) and the endoplasmic reticulum (ER). LG8 causes the ER to form foci of interconnecting tubules, which at the ultrastructural level appear similar to those previously reported in Arabidopsis roots after treatment with the herbicide oryzalin. In cotyledonary leaves, LG8 causes redistribution of a trans Golgi network (TGN) marker to the vacuole. LG8 affects the anterograde secretory pathway by inducing secretion of vacuolar cargo and preventing the brassinosteroid receptor BRI1 from reaching the plasma membrane. Uptake and arrival at the TGN of the endocytic marker FM4-64 is not affected. Unlike the ADP ribosylation factor-GTP exchange factor (ARF-GEF) inhibitor brefeldin A (BFA), LG8 affects these post-Golgi events without causing the formation of BFA bodies. Up to concentrations of 50 µm, the effects of LG8 are reversible.

An Arabidopsis reticulon and the atlastin homologue RHD3-like2 act together in shaping the tubular endoplasmic reticulum.

The endoplasmic reticulum (ER) is a network of membrane sheets and tubules connected via three-way junctions. A family of proteins, the reticulons, are responsible for shaping the tubular ER. Reticulons interact with other tubule-forming proteins (Dp1 and Yop1p) and the GTPase atlastin. The Arabidopsis homologue of Dp1/Yop1p is HVA22. We show here that a seed-specific isoform of HVA22 labels the ER in tobacco (Nicotiana tabacum) cells but its overexpression does not alter ER morphology. The closest plant homologue of atlastin is RHD3. We show that RHD3-like 2 (RL2), the seed-specific isoform of RHD3, locates to the ER without affecting its shape or Golgi mobility. Expression of RL2-bearing mutations within its GTPase domain induces the formation of large ER strands, suggesting that a functional GTPase domain is important for the formation of three-way junctions. Coexpression of the reticulon RTNLB13 with RL2 resulted in a dramatic alteration of the ER network. This alteration did not depend on an active GTPase domain but required a functional reticulon, as no effect on ER morphology was seen when RL2 was coexpressed with a nonfunctional RTNLB13. RL2 and its GTPase mutants coimmunoprecipitate with RTNLB13. These results indicate that RL2 and RTNLB13 act together in modulating ER morphology.

LG186: An inhibitor of GBF1 function that causes Golgi disassembly in human and canine cells.

Brefeldin A-mediated inhibition of ADP ribosylation factor (Arf) GTPases and their guanine nucleotide exchange factors, Arf-GEFs, has been a cornerstone of membrane trafficking research for many years. Brefeldin A (BFA) is relatively non-selective inhibiting at least three targets in human cells, Golgi brefeldin A resistance factor 1 (GBF1), brefeldin A inhibited guanine nucleotide exchange factor 1 (BIG1) and brefeldin A inhibited guanine nucleotide exchange factor 2 (BIG2). Here, we show that the previously described compound Exo2 acts through inhibition of Arf-GEF function, but causes other phenotypic changes that are not GBF1 related. We describe the engineering of Exo2 to produce LG186, a more selective, reversible inhibitor of Arf-GEF function. Using multiple-cell-based assays and GBF1 mutants, our data are most consistent with LG186 acting by selective inhibition of GBF1. Unlike other Arf-GEF and reported GBF1 inhibitors including BFA, Exo2 and Golgicide A, LG186 induces disassembly of the Golgi stack in both human and canine cells.

Preferences of Australian healthcare providers regarding education on long-term health after hypertensive disorders of pregnancy: a qualitative study.

OBJECTIVES: To explore Australian healthcare providers' (HCPs') preferred content, format and access to education regarding long-term health after hypertensive disorder of pregnancy (HDP), in order to guide the development of education programmes. DESIGN AND SETTING: A qualitative study using a framework analysis was undertaken. Registered HCP who were practising in Australia and previously completed a survey about long-term health after HDP were invited to participate. PARTICIPANTS: Twenty HCP were interviewed, including midwives, specialist obstetrician/gynaecologists, general practitioners with a diploma in obstetrics and gynaecology, and cardiologists. PRIMARY AND SECONDARY OUTCOME MEASURES: Exploration of preferred content, format and distribution of educational material post-HDP. RESULTS: Twenty HCP were interviewed in April to May 2020. Four main categories were identified. 'Obtaining evidence-based information for own learning' addressing own learning with preference for multi-disciplinary education, preferably endorsed or facilitated by professional organisations. 'Optimising the referral process from hospital to community health services' was about the need for structured long-term follow-up to transition from hospital to community health and align with HDP guidelines. 'Facilitating women's health literacy' addressed the need for evidence-based, print or web-based material to assist risk discussions with women. 'Seizing educational opportunities' addressed the responsibility of all HCP to identify education opportunities to initiate key health discussions with women. CONCLUSIONS: HCP provided ideas on content, format and access of education regarding long-term health post-HDP within the parameters of the Australian healthcare context. This evidence will guide educational developments for HCP on post-HDP health to ensure they can better care for women and families.

Disulfide formation in plant storage vacuoles permits assembly of a multimeric lectin.

The ER (endoplasmic reticulum) has long been considered the plant cell compartment within which protein disulfide bond formation occurs. Members of the ER-located PDI (protein disulfide isomerase) family are responsible for oxidizing, reducing and isomerizing disulfide bonds, as well as functioning as chaperones to newly synthesized proteins. In the present study we demonstrate that an abundant 7S lectin of the castor oil seed protein storage vacuole, RCA (Ricinus communis agglutinin 1), is folded in the ER as disulfide bonded A-B dimers in both vegetative cells of tobacco leaf and in castor oil seed endosperm, but that these assemble into (A-B)2 disulfide-bonded tetramers only after Golgi-mediated delivery to the storage vacuoles in the producing endosperm tissue. These observations reveal an alternative and novel site conducive for disulfide bond formation in plant cells.

Cytosolic chaperones influence the fate of a toxin dislocated from the endoplasmic reticulum.

The plant cytotoxin ricin enters target mammalian cells by receptor-mediated endocytosis and undergoes retrograde transport to the endoplasmic reticulum (ER). Here, its catalytic A chain (RTA) is reductively separated from the cell-binding B chain, and free RTA enters the cytosol where it inactivates ribosomes. Cytosolic entry requires unfolding of RTA and dislocation across the ER membrane such that it arrives in the cytosol in a vulnerable, nonnative conformation. Clearly, for such a dislocated toxin to become active, it must avoid degradation and fold to a catalytic conformation. Here, we show that, in vitro, Hsc70 prevents aggregation of heat-treated RTA, and that RTA catalytic activity is recovered after chaperone treatment. A combination of pharmacological inhibition and cochaperone expression reveals that, in vivo, cytosolic RTA is scrutinized sequentially by the Hsc70 and Hsp90 cytosolic chaperone machineries, and that its eventual fate is determined by the balance of activities of cochaperones that regulate Hsc70 and Hsp90 functions. Cytotoxic activity follows Hsc70-mediated escape of RTA from an otherwise destructive pathway facilitated by Hsp90. We demonstrate a role for cytosolic chaperones, proteins typically associated with folding nascent proteins, assembling multimolecular protein complexes and degrading cytosolic and stalled, cotranslocational clients, in a toxin triage, in which both toxin folding and degradation are initiated from chaperone-bound states.

Maternal Adiposity and Energy Balance After Normotensive and Preeclamptic Pregnancies.

BACKGROUND: Preeclampsia is a major pregnancy complication associated with long-term maternal cardiometabolic disease. Research generally is focused on metabolic and pathophysiological changes during pregnancy; however, there is much less focus on the early postpartum period in subjects who suffered preeclampsia. The aim of this study was to (1) characterize energy intake and expenditure 6 months following normotensive and preeclamptic pregnancies and (2) examine associations between energy balance, body composition, insulin resistance measures (HOMA-IR), and clinical characteristics. DESIGN: A cross-sectional study 6 months following normotensive (n = 75) and preeclamptic (n = 22) pregnancies was performed. Metabolic measurements included anthropometrics measures, body composition via bioelectrical impedance analysis, 24-h energy expenditure via SenseWear Armbands, energy intake via a 3-day food diary, and serum metabolic parameters. RESULTS: Six months following preeclampsia, women had a significantly higher weight (77.3 ± 20.9 kg vs 64.5 ± 11.4 kg, P = 0.01), fat mass percentage (FM%; 40.7 ± 7.4% vs 34.9 ± 8.1%, P = 0.004), and insulin resistance (HOMA-IR 2.2 ± 1.5 vs 1.0 ± 0.7, P = 0.003), as well as reduced HDL levels (1.5 ± 0.4 mmol/L vs 1.8 ± 0.4 mmol/L, P = 0.01) compared to normotensive women. Women post-preeclampsia had lower activity-related energy expenditure (P = 0.02) but a decreased total energy intake (P = 0.02), leading to a more negative energy balance compared to their normotensive counterparts (-1942 kJ/24 h vs -480 kJ/24 h, P = 0.02). CONCLUSION: Increases in insulin resistance and FM%, reduced high-density lipoprotein, and more sedentary lifestyles characterize the postpartum period following preeclamptic compared with normotensive pregnancies. Early post-preeclampsia interventions, such as lifestyle behavior change, should be implemented and assessed to determine whether they reduce long-term cardiometabolic risk in women who experienced preeclampsia during pregnancy.

Assessing Australian women's knowledge and knowledge preferences about long-term health after hypertensive disorders of pregnancy: a survey study.

OBJECTIVES: To (1) assess women's current knowledge regarding long-term cardiovascular health after hypertensive disorders of pregnancy (2) elicit women's preferred educational content and format regarding health after hypertensive disorders of pregnancy. DESIGN AND SETTING: A custom-created online survey exploring Australian women's knowledge about long-term health after hypertensive disorders of pregnancy, distributed through consumer groups and social media. PARTICIPANTS: 266 women with (n=174) or without (n=92) a history of hypertensive disorders of pregnancy. PRIMARY AND SECONDARY OUTCOME MEASURES: (1) Proportion of women identifying long-term health risks after hypertensive disorder of pregnancy using a 10-point risk knowledge score with 0-4 'low', 4.1-7.0 'moderate' and 7.1-10 'high'. (2) Exploration of preferred content, format and distribution of educational material post hypertensive disorder of pregnancy. RESULTS: Knowledge scores about health after hypertensive disorder of pregnancy were moderate in groups with and without a history of the disorder. Knowledge was highest regarding risk of recurrent hypertensive disorders in a subsequent pregnancy, 'moderate' for chronic hypertension and heart attack, 'moderate' and 'low' regarding risk of heart disease and 'low' for diabetes and renal disease. Only 36% of all participants were aware that risks start within 10 years after the affected pregnancy. The majority of respondents with a history of hypertensive disorder of pregnancy (76%) preferred receiving information about long-term health 0-6 months post partum from a healthcare provider (80%), key organisations (60%), social media (47%) and brochures/flyers (43%). CONCLUSIONS: Women's knowledge regarding health risks after hypertensive disorder of pregnancy was 'moderate', although with important disease-specific gaps such as increased risk of diabetes. Most women wanted to be informed about their long-term health from a healthcare provider.

Microbiome Understanding in Maternity Study (MUMS), an Australian prospective longitudinal cohort study of maternal and infant microbiota: study protocol.

INTRODUCTION: Pregnancy induces significant physiological and cardiometabolic changes, and is associated with alterations in the maternal microbiota. Increasing rates of prepregnancy obesity, metabolic abnormalities and reduced physical activity, all impact negatively on the microbiota causing an imbalance between the commensal microorganisms (termed dysbiosis), which may drive complications, such as gestational diabetes or hypertensive disorders. Considerable work is needed to define the inter-relationships between the microbiome, nutrition, physical activity and pregnancy outcomes. The role of the microbiota during pregnancy remains unclear. The aim of the study is to define microbiota signatures longitudinally throughout pregnancy and the first year post birth, and to identify key clinical and environmental variables that shape the female microbiota profile during and following pregnancy. METHODS AND ANALYSIS: The Microbiome Understanding in Maternity Study (MUMS) is an Australian prospective longitudinal cohort study involving 100 mother-infant pairs. Women are enrolled in their first trimester and followed longitudinally. Assessment occurs at <13+0, 20+0-24+6 and 32+0-36+6 weeks gestation, birth and 6 weeks, 6 months and 12 months postpartum. At each assessment, self-collected oral, vaginal and faecal samples are collected with an additional postpartum skin swab and breastmilk sample. Each infant will have oral, faecal and skin swab samples collected. Measurements include anthropometrics, body composition, blood pressure, serum hormonal and metabolic parameters and vaginal pH. Dietary intake, physical activity and psychological state will be assessed using validated self-report questionnaires, and pregnancy and infant outcomes recorded. Parametric and non-parametric hypothesis tests will be used to test the association between high-risk and low-risk pregnancies and their outcomes. ETHICS AND DISSEMINATION: The study received the following approval: South Eastern Sydney Local Health District Research Ethics Committee (17/293 (HREC/17/POWH/605). Results will be made available to the participants of MUMS, their families and the funding bodies; in the form of a summary document. Results for the greater maternity care community and other researchers will be disseminated through conferences, local, national and international presentations and peer-reviewed publications. TRIAL REGISTRATION NUMBER: ACTRN12618000471280 (prospectively registered).

The secretion inhibitor Exo2 perturbs trafficking of Shiga toxin between endosomes and the trans-Golgi network.

The small-molecule inhibitor Exo2 {4-hydroxy-3-methoxy-(5,6,7,8-tetrahydrol[1]benzothieno[2,3-d]pyrimidin-4-yl)hydraz-one benzaldehyde} has been reported to disrupt the Golgi apparatus completely and to stimulate Golgi-ER (endoplasmic reticulum) fusion in mammalian cells, akin to the well-characterized fungal toxin BFA (brefeldin A). It has also been reported that Exo2 does not affect the integrity of the TGN (trans-Golgi network), or the direct retrograde trafficking of the glycolipid-binding cholera toxin from the TGN to the ER lumen. We have examined the effects of BFA and Exo2, and found that both compounds are indistinguishable in their inhibition of anterograde transport and that both reagents significantly disrupt the morphology of the TGN in HeLa and in BS-C-1 cells. However, Exo2, unlike BFA, does not induce tubulation and merging of the TGN and endosomal compartments. Furthermore, and in contrast with its effects on cholera toxin, Exo2 significantly perturbs the delivery of Shiga toxin to the ER. Together, these results suggest that the likely target(s) of Exo2 operate at the level of the TGN, the Golgi and a subset of early endosomes, and thus Exo2 provides a more selective tool than BFA for examining membrane trafficking in mammalian cells.

The association of Shiga-like toxin with detergent-resistant membranes is modulated by glucosylceramide and is an essential requirement in the endoplasmic reticulum for a cytotoxic effect.

Receptor-mediated internalization to the endoplasmic reticulum (ER) and subsequent retro-translocation to the cytosol are essential sequential processes required for the productive intoxication of susceptible mammalian cells by Shiga-like toxin-1 (SLTx). Recently, it has been proposed that the observed association of certain ER-directed toxins and viruses with detergent-resistant membranes (DRM) may provide a general mechanism for their retrograde transport to endoplasmic reticulum (ER). Here, we show that DRM recruitment of SLTx bound to its globotriosylceramide (Gb(3)) receptor is mediated by the availability of other glycosphingolipids. Reduction in glucosylceramide (GlcCer) levels led to complete protection against SLTx and a reduced cell surface association of bound toxin with DRM. This reduction still allowed efficient binding and transport of the toxin to the ER. However, toxin sequestration within DRM of the ER was abolished under reduced GlcCer conditions, suggesting that an association of toxin with lipid microdomains or rafts in the ER (where these are defined by detergent insolubility) is essential for a later step leading to or involving retro-translocation of SLTx across the ER membrane. In support of this, we show that a number of ER residents, proteins intimately involved in the process of ER dislocation of misfolded proteins, are present in DRM.

Quality control: another player joins the ERAD cast.

The quality control system known as ERAD removes misfolded proteins from the ER to the cytosol for degradation. The AAA ATPase Cdc48p and ubiquitin ligases play crucial roles; their relationship has been unclear, but recent work has shown that the membrane protein Ubx2p links their functions in yeast.

Isolation and characterization of four type 2 ribosome inactivating pulchellin isoforms from Abrus pulchellus seeds.

Abrus pulchellus seeds contain at least seven closely related and highly toxic type 2 ribosome-inactivating pulchellins, each consisting of a toxic A-chain linked to a sugar binding B-chain. In the present study, four pulchellin isoforms (termed P I, P II, P III and P IV) were isolated by affinity, ion exchange and chromatofocusing chromatographies, and investigated with respect to toxicity and sugar binding specificity. Half maximal inhibitory concentration and median lethal dose values indicate that P I and P II have similar toxicities and that both are more toxic to cultured HeLa cells and mice than P III and P IV. Interestingly, the secondary structural characteristics and sugar binding properties of the respective pairs of isoforms correlate well with the two toxicity levels, in that P I/P II and P III/P IV form two specific subgroups. From the deduced amino acids sequences of the four isoforms, it is clear that the highest similarity within each subgroup is found to occur within domain 2 of the B-chains, suggesting that the disparity in toxicity levels might be attributed to subtle differences in B-chain-mediated cell surface interactions that precede and determine toxin uptake pathways.

ER dislocation: Cdc48p/p97 gets into the AAAct.

Misfolded or unassembled proteins present in the lumen of the endoplasmic reticulum are exported to the cytosol and degraded. Recent studies have implicated a complex containing the AAA ATPase Cdc48p/p97 in the export process.

The isolation and characterization of temperature-dependent ricin A chain molecules in Saccharomyces cerevisiae.

Ricin is a heterodimeric plant protein that is potently toxic to mammalian cells. Toxicity results from the catalytic depurination of eukaryotic ribosomes by ricin toxin A chain (RTA) that follows toxin endocytosis to, and translocation across, the endoplasmic reticulum membrane. To ultimately identify proteins required for these later steps in the entry process, it will be useful to express the catalytic subunit within the endoplasmic reticulum of yeast cells in a manner that initially permits cell growth. A subsequent switch in conditions to provoke innate toxin action would permit only those strains containing defects in genes normally essential for toxin retro-translocation, refolding or degradation to survive. As a route to such a screen, several RTA mutants with reduced catalytic activity have previously been isolated. Here we report the use of Saccharomyces cerevisiae to isolate temperature-dependent mutants of endoplasmic reticulum-targeted RTA. Two such toxin mutants with opposing phenotypes were isolated. One mutant RTA (RTAF108L/L151P) allowed the yeast cells that express it to grow at 37 degrees C, whereas the same cells did not grow at 23 degrees C. Both mutations were required for temperature-dependent growth. The second toxin mutant (RTAE177D) allowed cells to grow at 23 degrees C but not at 37 degrees C. Interestingly, RTAE177D has been previously reported to have reduced catalytic activity, but this is the first demonstration of a temperature-sensitive phenotype. To provide a more detailed characterization of these mutants we have investigated their N-glycosylation, stability, catalytic activity and, where appropriate, a three-dimensional structure. The potential utility of these mutants is discussed.

Pregnancy with gestational hypertension or preeclampsia: A qualitative exploration of women's experiences.

BACKGROUND: Hypertension complicates 10% of pregnancies and involves specialised care of the woman and her baby, a longer stay in hospital, and an increased risk of physical and mental morbidity. There is limited research reporting the woman's perspective on her experience, how she coped with it psychologically, and whether the care she received influenced her experience. AIM: To gain insight into women's experience of hypertension in pregnancy and to report on what mediating factors may help improve their experience. METHODS: A qualitative descriptive study was undertaken. Data were collected through a semi-structured, face to face interview at 10-12 months postpartum. In total, 20 women who had experienced hypertension in their pregnancy were interviewed. Thematic analysis was used to analyse the data. FINDINGS: Four main themes were identified. These were: Reacting to the diagnosis, Challenges of being a mother, Processing and accepting the situation, and Moving on from the experience. The mediating factors that improved the experience were Feeling safe and trusting the care providers, Having continuity of care and carer, and Valuing social support from partner, family and friends. CONCLUSION: The diagnosis of hypertension in pregnancy has a significant impact on women. This affects their pregnancy and birth experience and their pathway to motherhood. The implications of the findings for midwifery practice include having access to multidisciplinary continuity models of care and facilitating the support for these women.

Retrograde transport pathways utilised by viruses and protein toxins.

A model has been presented for retrograde transport of certain toxins and viruses from the cell surface to the ER that suggests an obligatory interaction with a glycolipid receptor at the cell surface. Here we review studies on the ER trafficking cholera toxin, Shiga and Shiga-like toxins, Pseudomonas exotoxin A and ricin, and compare the retrograde routes followed by these protein toxins to those of the ER trafficking SV40 and polyoma viruses. We conclude that there is in fact no obligatory requirement for a glycolipid receptor, nor even with a protein receptor in a lipid-rich environment. Emerging data suggests instead that there is no common pathway utilised for retrograde transport by all of these pathogens, the choice of route being determined by the particular receptor utilised.