An analytical approach to the implementation of genetically modified crops

Public scepticism towards genetically modified (GM) crops is increasing. To address this, the risks and benefits of GM crops must be examined across scientific disciplines, and be discussed with the authorities, the agricultural industry and the consumers. In a feasibility study we have systematically analysed the challenges of the development and marketing of GM crops in Europe. A life-cycle inventory was used together with established technology foresight techniques in an interdisciplinary and empirical framework. The approach taken in this study established a dialogue between stakeholders and provided a framework for discussions about the future direction of GM crops.     

Influence of malonyl-CoA and palmitate concentration on rate of palmitate oxidation in rat muscle

5-Aminoimidazole-4-carboxamide1--D-ribofuranoside(AICAR) is taken up by perfused skeletal muscle andphosphorylated to form5-aminoimidazole-4-carboxamide-1--D-ribofuraosyl-5'-monophosphate (analog of 5'-AMP) with consequent activation of AMP-activated protein kinase, phosphorylation of acetyl-CoA carboxylase, decrease inmalonyl-CoA, and increase in fatty acid oxidation. Thisstudy was designed to determine the effect of increasing levels ofpalmitate on the rate of fatty acid oxidation. Malonyl-CoAconcentration was manipulated with AICAR at different palmitateconcentrations. Rat hindlimbs were perfused with Krebs-Henseleitbicarbonate containing 4% bovine serum albumin, washed bovine redcells, 200 µU/ml insulin, 10 mM glucose, and different concentrationsof palmitate (0.1-1.0 mM) without or with AICAR (2.0 mM).Perfusion with medium containing AICAR was found to activateAMP-activated protein kinase in skeletal muscle, inactivate acetyl-CoAcarboxylase, and decrease malonyl-CoA at all concentrations ofpalmitate. The rate of palmitate oxidation increased as a function ofpalmitate concentration in both the presence and absence of AICAR butwas always higher in the presence of AICAR. These results provideadditional evidence that malonyl-CoA is an important regulator of therate of fatty acid oxidation at palmitate concentrations in thephysiological range.

     

Prediction of the articular eminence shape in a patient with unilateral hypoplasia of the right mandibular ramus before and after distraction osteogenesis—A simulation study

The aim of this work was to predict the shape of the articular eminence in a patient with unilateral hypoplasia of the right mandibular ramus before and after distraction osteogenesis (DO). Using a patient-specific musculoskeletal model of the mandible the hypothesis that the observed differences in this patient in the left and right articular eminence inclinations were consistent with minimisation of joint loads was tested. Moreover, a prediction was made of the final shape of the articular eminence after DO when the expected remodelling has reached a steady state. The individual muscle forces and the average TMJ loading were computed for each combination of articular eminence angles both before and after DO. This exhaustive parameter study provides a full overview of average TMJ loading depending on the angles of the articular eminences. Before DO the parameter study resulted in different articular eminence inclinations between left and right sides consistent with patient data obtained from CT scans, indicating that in this patient the articular eminence shapes result from minimisation of joint loads. The simulation model predicts development of almost equal articular eminence shapes after DO. The same tendency was observed in cone beam CT scans (NewTom) of the patient taken 6.5 years after surgery.     

Beta-Lactamase Producing Escherichia coli Isolates in Imported and Locally Produced Chicken Meat from Ghana

The use of antibiotics in food animals is of public health concern, because resistant zoonotic pathogens can be transmitted to humans. Furthermore, global trade with food may rapidly spread multi-resistant pathogens between countries and even continents. The purpose of the study was to investigate whether imported chicken meat and meat from locally reared chicken are potential sources for human exposure to multi resistant Escherichia coli isolates. 188 samples from imported and locally produced chicken meat were sampled and analyzed. 153 bacteria isolates were successfully cultured and identified as E. coli using MALDI-ToF. Of these 109 isolates were from meat whereas the remaining 44 were isolated from the cloaca of locally reared live chickens. Antimicrobial susceptibility test was done on the identified E. coli isolates. Additionally, beta-lactamases production (ESBL and/or AmpC) were phenotypically confirmed on all isolates showing resistance to cefpodoxime. Beta-lactamase producing (BLP) E. coli meat isolates were further genotyped. Antimicrobial resistance to four antibiotic markers with highest resistance was detected more frequently in isolates from local chickens compared to imported chickens (tetracycline 88.9% vs. 57.5%, sulphonamide 75.0% vs. 46.6%, ampicillin 69.4% vs. 61.6% and trimethoprim 66.7% vs. 38.4%). Beta-lactamase production was found in 29 E. coli meat isolates, with 56.9% of them being multiple drug resistant (≥ 3). The predominant phylogroup identified was B1 followed by A and D, with similar distribution among the isolates from meat of locally reared chickens and imported chickens. Beta-lactamase producing genotype bla _CTX-M-15 (50%; 10/20) was the most frequently drug resistant gene detected. More BLP E. coli isolates were found in imported chicken meat compared to locally reared chickens, demonstrating that these isolates may be spreading through food trade. In conclusion, both imported and locally produced chicken meats are potential sources for human exposure to BLP E. coli.     

Interactions of Francisella tularensis with Alveolar Type II Epithelial Cells and the Murine Respiratory Epithelium

Francisella tularensis is classified as a Tier 1 select agent by the CDC due to its low infectious dose and the possibility that the organism can be used as a bioweapon. The low dose of infection suggests that Francisella is unusually efficient at evading host defenses. Although ~50 cfu are necessary to cause human respiratory infection, the early interactions of virulent Francisella with the lung environment are not well understood. To provide additional insights into these interactions during early Francisella infection of mice, we performed TEM analysis on mouse lungs infected with F. tularensis strains Schu S4, LVS and the O-antigen mutant Schu S4 waaY::TrgTn. For all three strains, the majority of the bacteria that we could detect were observed within alveolar type II epithelial cells at 16 hours post infection. Although there were no detectable differences in the amount of bacteria within an infected cell between the three strains, there was a significant increase in the amount of cellular debris observed in the air spaces of the lungs in the Schu S4 waaY::TrgTn mutant compared to either the Schu S4 or LVS strain. We also studied the interactions of Francisella strains with human AT-II cells in vitro by characterizing the ability of these three strains to invade and replicate within these cells. Gentamicin assay and confocal microscopy both confirmed that F. tularensis Schu S4 replicated robustly within these cells while F. tularensis LVS displayed significantly lower levels of growth over 24 hours, although the strain was able to enter these cells at about the same level as Schu S4 (1 organism per cell), as determined by confocal imaging. The Schu S4 waaY::TrgTn mutant that we have previously described as attenuated for growth in macrophages and mouse virulence displayed interesting properties as well. This mutant induced significant airway inflammation (cell debris) and had an attenuated growth phenotype in the human AT-II cells. These data extend our understanding of early Francisella infection by demonstrating that Francisella enter significant numbers of AT-II cells within the lung and that the capsule and LPS of wild type Schu S4 helps prevent murine lung damage during infection. Furthermore, our data identified that human AT-II cells allow growth of Schu S4, but these same cells supported poor growth of the attenuated LVS strain in vitro. Collectively, these data further our understanding of the role of AT-II cells in Francisella infections.     

Post-Prandial Protein Handling: You Are What You Just Ate

Background

Protein turnover in skeletal muscle tissue is highly responsive to nutrient intake in healthy adults.

Objective

To provide a comprehensive overview of post-prandial protein handling, ranging from dietary protein digestion and amino acid absorption, the uptake of dietary protein derived amino acids over the leg, the post-prandial stimulation of muscle protein synthesis rates, to the incorporation of dietary protein derived amino acids in de novo muscle protein.

Design

12 healthy young males ingested 20 g intrinsically [1-¹³C]-phenylalanine labeled protein. In addition, primed continuous L-[ring-²H₅]-phenylalanine, L-[ring-²H₂]-tyrosine, and L-[1-¹³C]-leucine infusions were applied, with frequent collection of arterial and venous blood samples, and muscle biopsies throughout a 5 h post-prandial period. Dietary protein digestion, amino acid absorption, splanchnic amino acid extraction, amino acid uptake over the leg, and subsequent muscle protein synthesis were measured within a single in vivo human experiment.

Results

55.3±2.7% of the protein-derived phenylalanine was released in the circulation during the 5 h post-prandial period. The post-prandial rise in plasma essential amino acid availability improved leg muscle protein balance (from -291±72 to 103±66 μM·min^-1·100 mL leg volume^-1; P<0.001). Muscle protein synthesis rates increased significantly following protein ingestion (0.029±0.002 vs 0.044±0.004%·h^-1 based upon the muscle protein bound L-[ring-²H₅]-phenylalanine enrichments (P<0.01)), with substantial incorporation of dietary protein derived L-[1-¹³C]-phenylalanine into de novo muscle protein (from 0 to 0.0201±0.0025 MPE).

Conclusion

Ingestion of a single meal-like amount of protein allows ~55% of the protein derived amino acids to become available in the circulation, thereby improving whole-body and leg protein balance. About 20% of the dietary protein derived amino acids released in the circulation are taken up in skeletal muscle tissue following protein ingestion, thereby stimulating muscle protein synthesis rates and providing precursors for de novo muscle protein synthesis.

Trial Registration

trialregister.nl 3638