Investigating the genetic components of tuber bruising in a breeding population of tetraploid potatoes

BACKGROUND

Tuber bruising in tetraploid potatoes (Solanum tuberosum) is a trait of economic importance, as it affects tubers' fitness for sale. Understanding the genetic components affecting tuber bruising is a key step in developing potato lines with increased resistance to bruising. As the tetraploid setting renders genetic analyses more complex, there is still much to learn about this complex phenotype. Here, we used capture sequencing data on a panel of half-sibling populations from a breeding programme to perform a genome-wide association analysis (GWAS) for tuber bruising. In addition, we collected transcriptomic data to enrich the GWAS results. However, there is currently no satisfactory method to represent both GWAS and transcriptomics analysis results in a single visualisation and to compare them with existing knowledge about the biological system under study.

RESULTS

When investigating population structure, we found that the STRUCTURE algorithm yielded greater insights than discriminant analysis of principal components (DAPC). Importantly, we found that markers with the highest (though non-significant) association scores were consistent with previous findings on tuber bruising. In addition, new genomic regions were found to be associated with tuber bruising. The GWAS results were backed by the transcriptomics differential expression analysis. The differential expression notably highlighted for the first time the role of two genes involved in cellular strength and mechanical force sensing in tuber resistance to bruising. We proposed a new visualisation, the HIDECAN plot, to integrate the results from the genomics and transcriptomics analyses, along with previous knowledge about genomic regions and candidate genes associated with the trait.

CONCLUSION

This study offers a unique genome-wide exploration of the genetic components of tuber bruising. The role of genetic components affecting cellular strength and resistance to physical force, as well as mechanosensing mechanisms, was highlighted for the first time in the context of tuber bruising. We showcase the usefulness of genomic data from breeding programmes in identifying genomic regions whose association with the trait of interest merit further investigation. We demonstrate how confidence in these discoveries and their biological relevance can be increased by integrating results from transcriptomics analyses. The newly proposed visualisation provides a clear framework to summarise of both genomics and transcriptomics analyses, and places them in the context of previous knowledge on the trait of interest.

TriPoly: haplotype estimation for polyploids using sequencing data of related individuals

Motivation

Knowledge of haplotypes, i.e. phased and ordered marker alleles on a chromosome, is essential to answer many questions in genetics and genomics. By generating short pieces of DNA sequence, high-throughput modern sequencing technologies make estimation of haplotypes possible for single individuals. In polyploids, however, haplotype estimation methods usually require deep coverage to achieve sufficient accuracy. This often renders sequencing-based approaches too costly to be applied to large populations needed in studies of Quantitative Trait Loci.

Results

We propose a novel haplotype estimation method for polyploids, TriPoly, that combines sequencing data with Mendelian inheritance rules to infer haplotypes in parent-offspring trios. Using realistic simulations of both short and long-read sequencing data for banana (Musa acuminata) and potato (Solanum tuberosum) trios, we show that TriPoly yields more accurate progeny haplotypes at low coverages compared to existing methods that work on single individuals. We also apply TriPoly to phase Single Nucleotide Polymorphisms on chromosome 5 for a family of tetraploid potato with 2 parents and 37 offspring sequenced with an RNA capture approach. We show that TriPoly haplotype estimates differ from those of the other methods mainly in regions with imperfect sequencing or mapping difficulties, as it does not rely solely on sequence reads and aims to avoid phasings that are not likely to have been passed from the parents to the offspring.

Availability and implementation

TriPoly has been implemented in Python 3.5.2 (also compatible with Python 2.7.3 and higher) and can be freely downloaded at https://github.com/EhsanMotazedi/TriPoly.

Supplementary information

Supplementary data are available at Bioinformatics online.

Mirror therapy and treadmill training for patients with chronic stroke: a pilot randomized controlled trial

BACKGROUND

Previous lower-limb mirror therapy research has focused on non-weight bearing interventions.

OBJECTIVES

The primary aim of this study was to investigate the effect and feasibility of a combination of mirror therapy and treadmill training on post-stroke lower-limb recovery compared to a placebo intervention.

METHODS

All patients (N = 30) walked on a treadmill for 30 min per day, 3 days per week, for 4 weeks. The mirror therapy and treadmill training group (n = 15) walked on the treadmill while viewing a reflection of their non-paretic limb in a mirror positioned in their mid-sagittal plane. The placebo group (n = 15) received no mirror visual feedback due to an altered mirror position.

PRIMARY OUTCOME MEASURES

Ten Metre Walk Test (10MWT) and Six Minute Walk Test (6MWT).

SECONDARY OUTCOME MEASURES

Modified Ashworth Scale (MAS) and Fugl-Meyer Assessment-Lower Extremity (FMA-LE). Feasibility was appraised by examining participant compliance and any adverse events.

RESULTS

No significant between group differences were demonstrated for the 10MWT, 6MWT or FMA-LE at post-training or 3-month follow-up assessment. A significant between group difference on the MAS was demonstrated in the reduction of ankle dorsiflexion muscle tone (p = 0.006) and ankle plantarflexion muscle tone (p = 0.01) in the mirror therapy group compared to the placebo group at post-training assessment but not at 3-month follow-up.

CONCLUSION

Our study reveals that in our group of patients with chronic stroke, mirror therapy combined with treadmill training facilitated significant reductions in ankle muscle tone (p < 0.05) compared to a placebo intervention.

Mirror therapy for improving lower limb motor function and mobility after stroke: A systematic review and meta-analysis

BACKGROUND

Mirror therapy has been proposed as an effective intervention for lower limb rehabilitation post stroke.

RESEARCH QUESTION

This systematic review with meta-analysis examined if lower limb mirror therapy improved the primary outcome measures of muscle tone and motor function and the secondary outcome measures balance characteristics, functional ambulation, walking velocity, passive range of motion (PROM) for ankle dorsiflexion and gait characteristics in patients with stroke compared to other interventions.

METHODS

Standardised mean differences (SMD) and mean differences (MD) were used to assess the effect of mirror therapy on lower limb functioning.

RESULTS

Nine studies were included in the review. Among the primary outcome measures there was evidence of a significant effect of mirror therapy on motor function compared with sham and non-sham interventions (SMD 0.54; 95% CI 0.24-0.93). Furthermore, among the secondary outcome measures there was evidence of a significant effect of mirror therapy for balance capacity (SMD -0.55; 95% CI -1.01 to -0.10), walking velocity (SMD 0.71; 95% CI 0.35-1.07), PROM for ankle dorsiflexion (SMD 1.20; 95% CI 0.71-1.69) and step length (SMD 0.56; 95% CI -0.00 to 1.12).

SIGNIFICANCE

The results indicate that using mirror therapy for the treatment of certain lower limb deficits in patients with stroke may have a positive effect. Although results are somewhat positive, overly favourable interpretation is cautioned due to methodological issues concerning included studies.

A single unit transfusion policy reduces red cell transfusions in general medical in-patients

BACKGROUND

The NICE guidelines for blood transfusion and the patient blood management recommendations state that a single unit of red cells should be the standard dose for patients with stable anaemia who are not bleeding. Studies have shown that changing clinical transfusion practice can be difficult and that many clinicians' order two units of blood as standard for patients needing a transfusion.

AIM

A collaborative project between NHS Blood and Transplant and Kings College Hospital started in September 2014 to evaluate the impact of a single unit policy on blood usage.

DESIGN METHODS

Training and education was undertaken for clinical staff on eight general medical wards and all staff working in the blood transfusion laboratory. We collected transfusion data for 12 months, (6 months before and after implementation).

RESULTS

There was a decrease of 50% red cell unit usage between the two periods, equating to a unit cost saving of £28 670. The number of single unit transfusions, increased from 30 to 53% whilst the number of two units decreased from 65 to 43% (P < 0.001).

DISCUSSION/CONCLUSION

This project has shown that transfusion practice can be changed and savings in blood usage can be achieved through the successful implementation of the single unit transfusions policy. Key to the implementation was engagement from key medical staff within the medical department in which the policy was implemented and support from the hospital transfusion team. Continued attention and training shall be needed to support these, and implement other, patient blood management recommendations.

Urinary F2 -Isoprostanes in Cats with International Renal Interest Society Stage 1-4 Chronic Kidney Disease

BACKGROUND

F₂ -isoprostanes, a biomarker of oxidant injury, increase with advancing chronic kidney disease (CKD) in humans. In cats, the relationship between CKD and oxidative stress is poorly understood.

OBJECTIVES

To determine whether cats with advancing CKD have increasing urinary F₂ -isoprostanes.

ANIMALS

Control cats without evidence of CKD (≥6 years old; n = 11), and cats with IRIS stage 1 (n = 8), 2 (n = 38), 3 (n = 21), and 4 (n = 10) CKD.

METHODS

This was a prospective observational study. Urinary F₂ -isoprostanes (specifically free 15-F_2t -isoprostanes) normalized to urine creatinine (IsoPs) were compared among groups and tested for correlations with blood pressure, proteinuria, serum creatinine concentration, and urine specific gravity. The IsoPs also were compared between cats with and without hypertension or proteinuria, and in cats fed predominantly standard versus renal diets.

RESULTS

Urinary IsoPs were increased, but not significantly, in cats with stage 1 CKD (median 263 pg/mg creatinine; range, 211-380) compared to controls (182 pg/mg; range, 80-348) and decreased significantly from stage 1 through advancing CKD (stage 2, 144 pg/mg; range, 49-608; stage 3, 102 pg/mg; range, 25-158; stage 4, 67 pg/mg; range, 26-117; P < .01). Urinary IsoPs were inversely correlated with serum creatinine (r = -0.66, P < .0001).

CONCLUSION AND CLINICAL IMPORTANCE

Urinary IsoPs are significantly higher in early CKD (stage 1) compared to cats with more advanced CKD. Additional studies are warranted to characterize oxidative stress in cats with stage 1 CKD and determine whether early antioxidant treatments have a protective effect on CKD progression.

Psoriasis and adverse pregnancy outcomes: a systematic review of observational studies

Psoriasis is a chronic inflammatory disorder with significant physical and psychological sequelae. The majority of individuals experience disease onset in early adult life - for women this often occurs during their reproductive years. While some autoimmune diseases have been shown to affect pregnancy outcomes adversely, such a relationship has not been well studied in psoriasis. We searched PubMed, Embase and the Cochrane database for published articles examining psoriasis and adverse pregnancy outcomes, and included observational studies and clinical trials evaluating direct measures of maternal and fetal morbidity and mortality. Four of the nine included articles reported a statistically significant increase in the risk of at least one outcome, including spontaneous abortion, caesarean delivery, low birth weight, macrosomia, large-for-gestational age, and a composite outcome consisting of both prematurity and low birth weight. However, these associations were not always consistent across studies. Overall, there was no clear evidence of increased adverse outcomes in pregnant women with psoriasis.

Genotypic resistance testing in HIV-infected pregnant women in an urban setting

This study examines the utility of HIV genotypic resistance testing (GT) in pregnant women at their initial pregnancy evaluation. A retrospective medical record review of 50 consecutive HIV-infected pregnant women in whom GT was obtained in the Bronx, New York was conducted. Twenty-eight (56%) were antiretroviral experienced, including 12 on antiretroviral therapy (ART) at time of GT. Major mutations were found in 11 (24%) of 45 amplifiable GTs. Major resistance mutations were identified against nucleoside reverse transcriptase inhibitors (NRTIs) in six (13%) patients; against non-nucleoside reverse transcriptase inhibitors (NNRTIs) in eight (18%) patients, and against protease inhibitors in two (4%) patients. Duration of ART exposure was significantly associated with identification of resistance mutations by GT for NRTIs and NNRTIs ( P ≥0.05). Results of this study indicate that GT at presentation may have implications on the initial choice of ART in up to one-quarter of HIV-infected pregnant women, especially with current or prior antiretroviral use.

London Trauma Conference 2015

I1: Trauma, Pre-hospital and Cardiac Arrest Care 2015

Pascale Avery, Leopold Salm, Flora Bird

A1: Retrospective evaluation of HEMS ‘Direct to CT’ protocol

Anja Hutchinson, Ashley Matthies, Anthony Hudson, Heather Jarman

A2 Rush hour – Crush hour: temporal relationship of cyclist vs. HGV trauma admissions. A single site observational study

Maria Bergman Nilsson, Tom Konig, Nigel Tai

A3 Semiprone position endotracheal intubation during continuous cardiopulmonary resuscitation in drowned children with regurgitation: a case report and experimental manikin study

Espen Fevang, Børge Hognestad, Håkon B. Abrahamsen

A4 An audit of CO2 A-a gradient in non-trauma patients receiving pre-hospital anaesthesia

Olivia V Cheetham, Matthew JC Thomas, Kieron D Rooney

A5 Can the use of c-spine immobilisation collars be avoided in non-trauma patients presenting to the Emergency Department?

Josephine Murray, Malcolm Tunnicliff

A6 Curriculum mapping in ED point of care simulation

Joseph W Collinson, Thomas Brown, Christopher Pritchett

A7 Point of care multidisciplinary trauma team simulation & participant satisfaction in a geographically remote trauma unit in Cornwall

Christopher SA Pritchett, Mark Jadav, Gareth Meredith, Jamie Plumb, Steve Harris, Roger Langford

A8 Conservative management of head injury inpatients - the challenge of simplifying injury management in a non-neurosurgical hospital

JG Hunter, A Sage, R Madden, O Flamank, B Broadbent, S Marsh, H Lewis, E Daniels, N Roberts

A9 Improving the care of traumatic brain injury at non-neurosurgical hospitals: Introducing a head injury pathway and single place of care is associated with significant improvements in neurological observation

JG Hunter, A Sage, R Madden, O Flamank, B Broadbent, S Marsh, H Lewis, E Daniels, N Lin, N Roberts

A10 The experience of inter-disciplinary students undertaking cardiac arrest moulage training

Samuel Bulford, Silas Houghton-Budd, Sam Pearson, Megan Clear-Hill

A11 Impact brain apnoea – nine cases

David J Menzies, James P Leonard, Conor Keogh, Ray Quinn, John D Hinds

A12 Time well spent? Improving the performance improvement programme in a busy Trauma Unit

N Roberts, D Ashton-Cleary, M Jadav

A14 Clinical significant and outcome of pulmonary contusions in patients with blunt chest trauma

Ismail Mahmood, Ayman El-Menyar, Basil Younis, Ahmed Khalid, Syed Nabir, Mohamed Nadeem Ahmed, Omer Al-Yahri, Hassan Al-Thani

A15 Plastics operative workload in major trauma centres: a national prospective survey

Katie Young, Susan A. Hendrickson, Georgina Phillips, Matthew D. Gardiner, Shehan Hettiaratchy

A16 A survey to assess the accuracy of estimating height by pre-hospital clinicians: can we reliably predict those most at risk of serious injury?

Alexandra Alice Crossland, Anthony Hudson

A17 An audit of the cause, outcome and adherence to treatment Standard Operating Procedure (SOP) for all traumatic cardiac arrests at a Helicopter Emergency Medical Service over a 12-month period

Nicholas C Brassington, Anthony Hudson, Emily McWhirter

A18 Should we “stay-and-play? A study of patient physiology in Norwegian Helicopter Emergency Services

Bjørn O Reid, Marius Rehn, Oddvar Uleberg, Andreas J Krüger

A19 Training in resuscitative thoracotomy: have we cracked it? A survey of higher Emergency Medicine trainees in London

Cara Jennings, Yasmin Kapadia, Duncan Bew

A20 London’s Air Ambulance (LAA): 25-years of drownings in an urban environment

Jenny Townsend, Tom P Hurst, Elizabeth A Foster

A21 Live patients in trauma simulation – more than just simulation on a shoestring?

Thomas B Brown, Joseph Collinson, Christopher Pritchett, Toby Slade

A22 Collecting core data in pre-hospital critical care using a consensus based template

Kristin Tønsager, Marius Rehn, Kjetil G.Ringdal, Andreas J.Krüger

A23 Prehospital interventions before and after implementation of a physician staffed helicopter

Rasmus Hesselfeldt, Sandra Wulffeld, Asger Sonne, Lars S. Rasmussen, Jacob Steinmetz

A24 Duration of ventilation following prehospital drug assisted intubation; a retrospective review

Thomas J Renninson, Nadine Thomson, Harvey Pynn, Timothy J Hooper

A25 Non-haemorrhagic shock in trauma: a novel guideline for management in ED

Anthony Hudson, Jacinta Dawson, Ashley Matthies

A26 Patient-tailored triage decisions by anaesthetist-staffed pre-hospital critical care teams

Morten Langfeldt Friberg, Leif Rognås

A27 Anatomical accuracy and appropriate sizing of pre-hospital thoracostomies

Jessica FG Wills, Anthony Hudson

A28 Pre-hospital management of mass casualty civilian shootings

Conor DA Turner, Marius Rehn

A30 The prevalence of alcohol-related trauma recidivism: a systematic review

James Nunn, Mete Erdogan, Robert S. Green

A31 Development of a hospital-wide program for simulation-based training in trauma care and management

Samuel Minor, Mete Erdogan, Kathy Hartlen, Robert S. Green

A32 Out of Hospital Cardiac Arrests (OOHCA); lessons from Hollywood

Ruth Bird, Rachael L. Grupping

A33 Mechanism of injury as a predictor of severity of injury in road traffic collisions: a literature review

Amelia M. Stacey, Marius Rehn, David J. Lockey

A34 Lessons to be learned from prehospital airway intervention documentation? Are airway intervention documentation templates as successful in-hospital as prehospitally?

S. Abiks, L. Cutler, K. Monaghan, A. Al-Rais, C. Hymers, R. Bloomer, Y. Kapadia

A35 Novel biomarkers in prehospital management of traumatic brain injury (the PreTBI study protocol)

Sophie-Charlott Seidenfaden, Ingunn S. Riddervold, Hans Kirkegaard, Niels Juul, Morten T. Bøtker

A36 Hospital outcomes of traumatic railway incidents: a seven-year observational retrospective study of a major trauma centre

Alice Gao, Zane Perkins; Gareth Grier, Alex Tzannes

A37 Does taking a third crew member affect the on-scene time of HEMS jobs?

Nathan Hudson-Peacock, Quentin Otto, Laurie Phillipson, Rik Thomas, Ainsley Heyworth

A38 Does pre-hospital rapid sequence induction affect on-scene time of HEMS jobs?

Quentin Otto, Nathan Hudson-Peacock, Laurie Phillipson, Ainsley Heyworth, Erica Ley

A39 Code red: shock index as a prehospital indicator of massive haemorrhage

Daniel Banner, Ainsley Heyworth, Erica Ley

A40 Air ambulance tasking: how accurate are our current methods?

Madeleine Benson, Nathan Hudson-Peacock, Tony Stone, Erica Ley, Louise Rousson, Ainsley Heyworth

A41 Modern trauma burden in a district general hospital

Beth A Lineham, Matthew J Lee, Martin Gough

A42 Establishing a legal service for major trauma patients in two UK major trauma centres

William H Seligman, Hannah E Thould, Andrew Dinsmore, Charlotte Tan, Julian Thompson, C Andy Eynon, David J Lockey

A43 Prehospital assessment and care of patients – a study of the use of guidelines when assessing head trauma

Rebecka M Rubenson Wahlin, Veronica Lindström, Sari Ponzer, Veronica Vicente

A44 An audit of pre-hospital blood pressure management resulting from head injury

Pamela Eligio, Anthony Hudson

A45 The surgical contribution of surface shading volumetric rendering techniques in rib fracture management

Robert Young, Dimitri Amiras, Ian Sinha

Ankle function during hopping in subjects with functional instability of the ankle joint

A common mechanism of inversion injury involves a lateral movement producing a hypersupination of the ankle joint. To date, no study has investigated patterns of muscle activity, three-dimensional (3D) joint kinematics and kinetics simultaneously in a group of subjects with functional instability (FI) compared with a non-injured control group during a lateral hopping test. Twenty-six subjects with the subjective complaint of FI of the ankle joint and 24 non-injured healthy control subjects volunteered to participate in the study. We measured 3D lower limb kinematics, kinetics and surface electromyography (EMG) of the rectus femoris, tibialis anterior, peroneus longus and soleus muscle in all subjects during a lateral hop task for the period 200 ms pre- and post-initial contact (IC). FI subjects were observed to have a less-everted position of the ankle joint during the time period from 45 ms pre-IC to 95 ms post-IC (P<0.05). FI subjects were also found to have an increase in pre- and post-IC rectus femoris, tibialis anterior and solues EMG activity. The results suggest that subjects with FI exhibit changes in ankle joint movement and neuromuscular control that could predispose to further injury.

TREK-1 regulation by nitric oxide and cGMP-dependent protein kinase. An essential role in smooth muscle inhibitory neurotransmission

Potassium channels activated by membrane stretch may contribute to maintenance of relaxation of smooth muscle cells in visceral hollow organs. Previous work has identified K(+) channels in murine colon that are activated by stretch and further regulated by NO-dependent mechanisms. We have screened murine gastrointestinal, vascular, bladder, and uterine smooth muscles for the expression of TREK and TRAAK mRNA. Although TREK-1 was expressed in many of these smooth muscles, TREK-2 was expressed only in murine antrum and pulmonary artery. TRAAK was not expressed in any smooth muscle cells tested. Whole cell currents from TREK-1 expressed in mammalian COS cells were activated by stretch, and single channel recordings showed that the stretch-dependent conductance was due to 90 pS channels. Sodium nitroprusside (10(-6) or 10(-5) m) and 8-Br-cGMP (10(-4) or 10(-3) m) increased TREK-1 currents in perforated whole cell and single channel recordings. Mutation of the PKG consensus sequence at serine 351 blocked the stimulatory effects of sodium nitroprusside and 8-Br-cGMP on open probability without affecting the inhibitory effects of 8-Br-cAMP. TREK-1 encodes a component of the stretch-activated K(+) conductance in smooth muscles and may contribute to nitrergic inhibition of gastrointestinal muscles.

Novel voltage-dependent non-selective cation conductance in murine colonic myocytes

1. Two components of voltage-gated, inward currents were observed from murine colonic myocytes. One component had properties of L-type Ca(2+) currents and was inhibited by nicardipine (5 x 10(-7) M). A second component did not 'run down' during dialysis and was resistant to nicardipine (up to 10(-6) M). The nicardipine-insensitive current was activated by small depolarizations above the holding potential and reversed near 0 mV. 2. This low-voltage-activated current (I(LVA)) was resolved with step depolarizations positive to -60 mV, and the current rapidly inactivated upon sustained depolarization. The voltage of half-inactivation was -65 mV. Inactivation and activation time constants at -45 mV were 86 and 15 ms, respectively. The half-recovery time from inactivation was 98 ms at -45 mV. I(LVA) peaked at -40 mV and the current reversed at 0 mV. 3. I(LVA) was inhibited by Ni(2+) (IC(50) = 1.4 x 10(-5) M), mibefradil (10(-6) to 10(-5) M), and extracellular Ba(2+). Replacement of extracellular Na(+) with N-methyl-D-glucamine inhibited I(LVA) and shifted the reversal potential to -7 mV. Increasing extracellular Ca(2+) (5 x 10(-3) M) increased the amplitude of I(LVA) and shifted the reversal potential to +22 mV. I(LVA) was also blocked by extracellular Cs(+) (10(-4) M) and Gd(3+) (10(-6) M). 4. Warming increased the rates of activation and deactivation without affecting the amplitude of the peak current. 5. We conclude that the second component of voltage-dependent inward current in murine colonic myocytes is not a 'T-type' Ca(2+) current but rather a novel, voltage-gated non-selective cation current. Activation of this current could be important in the recovery of membrane potential following inhibitory junction potentials in gastrointestinal smooth muscle or in mediating responses to agonists.

Pacemaking in interstitial cells of Cajal depends upon calcium handling by endoplasmic reticulum and mitochondria

Pacemaker cells, known as interstitial cells of Cajal (ICC), generate electrical rhythmicity in the gastrointestinal tract. Pacemaker currents in ICC result from the activation of a voltage-independent, non-selective cation conductance, but the timing mechanism responsible for periodic activation of the pacemaker current is unknown. Previous studies suggest that pacemaking in ICC is dependent upon metabolic activity 1y1yand1 Ca2+ release from intracellular stores. We tested the hypothesis that mitochondrial Ca2+ handling may underlie the dependence of gastrointestinal pacemaking on oxidative metabolism. Pacemaker currents occurred spontaneously in cultured ICC and were associated with mitochondrial Ca2+ transients. Inhibition of the electrochemical gradient across the inner mitochondrial membrane blocked Ca2+ uptake and pacemaker currents in cultured ICC and blocked slow wave activity in intact gastrointestinal muscles from mouse, dog and guinea-pig. Pacemaker currents and rhythmic mitochondrial Ca2+ uptake in ICC were also blocked by inhibitors of IP3-dependent release of Ca2+ from the endoplasmic reticulum and by inhibitors of endoplasmic reticulum Ca2+ reuptake. Our data suggest that integrated Ca2+ handling by endoplasmic reticulum and mitochondria is a prerequisite of electrical pacemaking in the gastrointestinal tract.