Genetic manipulation of glutathione levels in lettuce: crop performance and resistance to tipburn

The four lettuce (Lactuca saliva) cvs. Evola, King Louie, Pic and Robusto were transformed with the binary expression construct pAFQ70.1, using Agrobacterium tumefaciens strain AGL 1. The construct carried the glutathione metabolic genes gshi, gshlI, phgpx and gorI. Both the gshI and gshII genes were fused to sequences encoding the pea glutathione reductase transit peptide (grIp), and were intended to influence glutathione synthesis and metabolism in the chloroplasts. Reverse transcriptase PCR analysis of cvs. King Louie, Pic and Robusto T0 transformants revealed that expression of the transgenes followed a varied pattern. These variations were most likely due to post-transcriptional gene silencing created by the presence of strong promoters, homology with endogenous plant genes and presence of multiple genes in a single vector. The presence of the transgenes, gshI, gshII, phgpx, and gorI, in cv. King Louie T3 homozygous lines was confirmed by genomic DNA dot blots and Southern blots. It was hypothesized that transformants would have an increased glutathione pool in the chloroplasts and thus would be able to withstand the damaging effects of active oxygen species generated by environmental stresses. Leaves of transgenic homozygous T3 cv. King Louie lines were shown to have a 2-fold greater glutathione concentration than their respective azygous counterparts, although total antioxidant activity was similar in all lines. However, this did not result in enhanced stress tolerance, with the homozygous lines exhibiting no physiological or morphological advantage compared to the azygous and wild-type lines when grown under saline stress (150 mM NaCl). Glasshouse trials during the summer of 2005 determined the susceptibility of cv. King Louie T3 homozygous, azygous and wild-type lines to the foliar, stress related disorder tipburn. Wild-type plants grown both under calcium deficient conditions at the University of Nottingham and in a trial at Elsoms Seeds Ltd., Spalding, UK, had a reduced incidence of tipburn compared to transgenic plants of the homozygous and azygous lines. Macroscopic of tipburnt leaves revealed the condition formed sporadically, with small dark sunken necrotic spots spreading along the leaf margin restricting leaf expansion. Microscopic transverse sections of tipburnt leaves showed total collapse, disintegration and necrosis of the leaf structure

Genetic manipulation of glutathione levels in lettuce: crop performance and resistance to tipburn

The four lettuce (Lactuca saliva) cvs. Evola, King Louie, Pic and Robusto were transformed with the binary expression construct pAFQ70.1, using Agrobacterium tumefaciens strain AGL 1. The construct carried the glutathione metabolic genes gshi, gshlI, phgpx and gorI. Both the gshI and gshII genes were fused to sequences encoding the pea glutathione reductase transit peptide (grIp), and were intended to influence glutathione synthesis and metabolism in the chloroplasts. Reverse transcriptase PCR analysis of cvs. King Louie, Pic and Robusto T0 transformants revealed that expression of the transgenes followed a varied pattern. These variations were most likely due to post-transcriptional gene silencing created by the presence of strong promoters, homology with endogenous plant genes and presence of multiple genes in a single vector. The presence of the transgenes, gshI, gshII, phgpx, and gorI, in cv. King Louie T3 homozygous lines was confirmed by genomic DNA dot blots and Southern blots. It was hypothesized that transformants would have an increased glutathione pool in the chloroplasts and thus would be able to withstand the damaging effects of active oxygen species generated by environmental stresses. Leaves of transgenic homozygous T3 cv. King Louie lines were shown to have a 2-fold greater glutathione concentration than their respective azygous counterparts, although total antioxidant activity was similar in all lines. However, this did not result in enhanced stress tolerance, with the homozygous lines exhibiting no physiological or morphological advantage compared to the azygous and wild-type lines when grown under saline stress (150 mM NaCl). Glasshouse trials during the summer of 2005 determined the susceptibility of cv. King Louie T3 homozygous, azygous and wild-type lines to the foliar, stress related disorder tipburn. Wild-type plants grown both under calcium deficient conditions at the University of Nottingham and in a trial at Elsoms Seeds Ltd., Spalding, UK, had a reduced incidence of tipburn compared to transgenic plants of the homozygous and azygous lines. Macroscopic of tipburnt leaves revealed the condition formed sporadically, with small dark sunken necrotic spots spreading along the leaf margin restricting leaf expansion. Microscopic transverse sections of tipburnt leaves showed total collapse, disintegration and necrosis of the leaf structure

Enterprise Systems Implementation Success in the Shakedown Phase

Enterprise systems (ES) are popular in both business and academia: many organizations adopt an ES and much has been published on the topic. However, we argue not much is known about success (and its contributing factors) during the different moments of an ES implementation, although this is highly relevant for practice. This study considers the relevant success factors during the shakedown phase of an ES implementation. We use a framework that incorporates three dimensions of success: user, correspondence, and system success. Each success dimension has its own set of success factors. We empirically study an ES implementation in its shakedown phase at a large university in the Netherlands, through conducting interviews and a survey. Results show that data accuracy, troubleshooting, and user support were rated the most important for ES implementation success, whereas business process reengineering (BPR), customization, and again data accuracy were evaluated the best for this ES implementation

Wind-tunnel experiments on cross-ventilative cooling in a generic isolated building with one heated wall:Impact of opening size

This paper presents wind-tunnel experiments of cross-ventilative cooling in a generic isolated building with an interior heated side wall. Two different sizes of openings are considered: large and small openings. Particle image velocimetry (PIV) is used to determine velocities in the vertical centerplane. Air temperatures in the vertical centerplane are measured using negative temperature coefficient (NTC) sensors. Surface temperatures on the heated wall are measured using an infrared camera. Surface heat fluxes are obtained using heat flux sensors. In both cases the indoor airflow is dominated by the jet through the openings, with higher velocities in the building with large openings. The air temperatures measured with small openings are up to 7.5 % larger than those with large openings. The surface heat fluxes are up to 20 % higher in the building with large openings. The interior convective heat transfer coefficients vary considerably across the heated wall for both opening sizes and can be very different (up to 5 times higher) from those obtained by existing internal convective heat transfer coefficient correlations. The measurement results give insight into the complexity of ventilative cooling and can be used to validate computational fluid dynamics (CFD) simulations of cross-ventilative cooling.</p

Cerebral blood flow and heart rate variability in chronic fatigue syndrome : a randomized cross-over study

Background: Pain, fatigue, and concentration difficulties are typical features of chronic fatigue syndrome (CFS). The exact underlying mechanisms of these symptoms are still unknown, but available evidence suggests an important role for impaired pain modulation. As evidence also suggests that pain modulation is related to cardiovascular mechanisms, it seems logical to investigate whether cerebral blood flow (CBF) and heart rate variability (HRV) are altered in these patients. Objectives: We aimed to investigate the role of the cardiovascular system in pain modulation and symptoms of CFS; the response of CBF and HRV to physical stress and their relation to the change in temporal summation (TS) of pressure pain and self-reported symptoms was evaluated. Study Design: A controlled, randomized cross-over trial. Setting: University Hospital Brussels. Methods: Twenty CFS patients and 20 sedentary healthy controls were included in this study. In both of the groups, the change in TS of pressure pain, CBF (using transcranial Doppler), and HRV (using finger plethysmography) was examined during physical and emotional stress (to control for potential bias), as well as their association mutually and with self-reported symptoms of pain, fatigue, and concentrations difficulties. Results: There was no significant interaction or group (F-values ranging from .100 to 1.862, P-values ranging from .754 to .181) effect in CBF or HRV parameters. HRV and CBF did change during physical exercise, but the changes did not differ between patients and controls. While pain scores during TS at the trapezius site reduced in the control group after the physical exercise protocol (P=.037), they did not change in the CFS group (P=.108), suggesting impaired pain modulation. There were no significant correlations between CBF, HRV, TS, and self-reported symptoms (all P-values of correlation analyses > .01). Limitations: Although effect sizes were medium to large, the study sample was relatively low. Also, the mild nature of the exercise bout is discussable. Nonetheless, this mild exercise was able to provoke endogenous pain modulation in the control group, which endorsed a proper execution of the cycling exercise. Moreover, mild exercises are more applicable to daily physical activities in CFS patients than vigorous exercises. Conclusion: These results seem to refute the previously suggested alterations of CBF/HRV in CFS patients. These cardiovascular parameters appear not to explain pain before, during, and following exercise

Lumbar spine segmentation in MR images: a dataset and a public benchmark

This paper presents a large publicly available multi-center lumbar spine magnetic resonance imaging (MRI) dataset with reference segmentations of vertebrae, intervertebral discs (IVDs), and spinal canal. The dataset includes 447 sagittal T1 and T2 MRI series from 218 patients with a history of low back pain. It was collected from four different hospitals and was divided into a training (179 patients) and validation (39 patients) set. An iterative data annotation approach was used by training a segmentation algorithm on a small part of the dataset, enabling semi-automatic segmentation of the remaining images. The algorithm provided an initial segmentation, which was subsequently reviewed, manually corrected, and added to the training data. We provide reference performance values for this baseline algorithm and nnU-Net, which performed comparably. We set up a continuous segmentation challenge to allow for a fair comparison of different segmentation algorithms. This study may encourage wider collaboration in the field of spine segmentation, and improve the diagnostic value of lumbar spine MRI