Harmonization of legislation and regulations to achieve food safety: US and Canada perspective

Trade in food and food ingredients among the nations of the world is rapidly expanding and, with this expansion, new supply chain partners, from globally disparate geographic regions, are being enrolled. Food and food ingredients are progressively sourced more from lesser developed nations. Food safety incidents in the USA and Canada show a high unfavorable correlation between illness outbreaks and imported foods. In the USA, for example, foodborne disease outbreaks caused by imported food appeared to rise in 2009 and 2010, and nearly half of the outbreaks, associated with imported food, implicated foods imported from areas which previously had not been associated with outbreaks. Projecting supply chains into new geographical regions raises serious questions about the capacity of the new supply chain partners to provide the requisite regulatory framework and sufficiently robust public health measures for ensuring the safety of the foods and foodstuffs offered for international trade. The laws, regulation and legislation among the many nations participating in the global food trade are, at best, inconsistent. These inconsistencies frequently give rise to trade disputes and cause large quantities of food to be at risk of destruction on the often dubious pretext that they are not safe. Food safety is often viewed through a political or normative lens. Often as not, this lens has been wrought absent scientific precision. Harmonization of food safety legislation around sound scientific principles, as advocated by the US Food Safety Modernization Act (FSMA), would ultimately promote trade and likely provide for incremental improvement in public health. Among the priority roles of most national governments are the advancement of commerce and trade, preservation of public health and ensuring domestic tranquility. Achieving these priorities is fundamental to creating and preserving the wealth of nations. Countries such as the Netherlands, Canada, Germany, Japan and the USA, for example, have very stable governments, are leaders in trade and commerce and enjoy high standards of public health. It is not by accident or coincidence that these nations are also among the world's wealthiest. Attainment of national priorities, especially those related to promoting trade in foodstuffs and also in preserving public health (food safety), would benefit greatly from international efforts in harmonizing food safety regulations and legislation. © 2013 Society of Chemical Industry     

Charge engineering of a protein domain to allow efficient ion-exchange recovery

We have created protein domains with extreme surface charge.These mutated domains allow for ion-exchange chromatographyunder conditions favourable for selective and efficient capture,using Escherichia coli as a host organism. The staphylococcalprotein A-derived domain Z (Z_wt) was used as a scaffold whenconstructing two mutants, Z_basic1 and Z_basic2, with high positivesurface charge. Far-ultraviolet circular dichroism measurementsshowed that they have a secondary structure content comparableto the parental molecule Z_wt. Although melting temperatures(T_m) of the engineered domains were lower than that of the wild-typeZ domain, both mutants could be produced successfully as intracellularfull-length products in E.coli and purified to homogeneity byion-exchange chromatography. Further studies performed on Z_basic1and Z_basic2 showed that they were able to bind to a cation exchangereven at pH values in the 9 to 11 range. A gene fusion betweenZ_basic2 and the acidic human serum albumin binding domain (ABD),derived from streptococcal protein G, was also constructed.The gene product Z_basic2–ABD could be purified using cation-exchangechromatography from a whole cell lysate to more than 90% purity.     

ATP-regulation of antioxidant properties and phenolics in litchi fruit during browning and pathogen infection process

The impact of energy level on antioxidant properties in relation to pericarp browning and loss of disease resistance of litchi fruit was investigated. Litchi fruits were vacuum-infiltrated with distiled water (control), 1 mM adenosine triphosphate (ATP) and 0.5 mM 2,4-dinitrophenol (DNP) under 75 kPa for 3 min before being inoculated with Peronophythora litchi or not. ATP-treated fruits presented higher activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX). Higher activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, reducing power and contents of phenolic compounds were also observed in ATP-treated fruit during storage. In contrast, DNP treatment lowered the enzymes activities, scavenging ability and the contents of phenolic compounds. Higher levels of antioxidant enzymatic system and non-enzymatic system were observed in P. litchii-inoculated fruits than those in non-inoculated fruits. Application of ATP and DNP exhibited a similar change patterns and effects in inoculated fruits. When related to previously reported ATP levels, the results suggested that ATP levels could regulate the antioxidant system. Sufficient available energy is crucial for inhibiting browning and preventing the loss of disease resistance in harvested litchi fruit.     

Live Cell FRET Imaging Reveals Amyloid β-Peptide Oligomerization in Hippocampal Neurons

Amyloid β-peptide (Aβ) oligomerization is believed to contribute to the neuronal dysfunction in Alzheimer disease (AD). Despite decades of research, many details of Aβ oligomerization in neurons still need to be revealed. Förster resonance energy transfer (FRET) is a simple but effective way to study molecular interactions. Here, we used a confocal microscope with a sensitive Airyscan detector for FRET detection. By live cell FRET imaging, we detected Aβ42 oligomerization in primary neurons. The neurons were incubated with fluorescently labeled Aβ42 in the cell culture medium for 24 h. Aβ42 were internalized and oligomerized in the lysosomes/late endosomes in a concentration-dependent manner. Both the cellular uptake and intracellular oligomerization of Aβ42 were significantly higher than for Aβ40. These findings provide a better understanding of Aβ42 oligomerization in neurons.     

Engineered Human Induced Pluripotent Cells Enable Genetic Code Expansion in Brain Organoids

Human induced pluripotent stem cell (hiPSC) technology has revolutionized studies on human biology. A wide range of cell types and tissue models can be derived from hiPSCs to study complex human diseases. Here, we use PiggyBac-mediated transgenesis to engineer hiPSCs with an expanded genetic code. We demonstrate that genomic integration of expression cassettes for a pyrrolysyl-tRNA synthetase (PylRS), pyrrolysyl-tRNA (PylT) and the target protein of interest enables site-specific incorporation of a non-canonical amino acid (ncAA) in response to an amber stop codon. Neural stem cells, neurons and brain organoids derived from the engineered hiPSCs continue to express the amber suppression machinery and produce ncAA-bearing reporter. The incorporated ncAA can serve as a minimal bioorthogonal handle for further modifications by labeling with fluorescent dyes. Site-directed ncAA mutagenesis will open a wide range of applications to probe and manipulate proteins in brain organoids and other hiPSC-derived cell types and complex tissue models.     

Study of Protein Adsorption During Sterile Filtration of Protein Formulations by ILC

Protein adsorption is usually regarded as the main reason for filter fouling in sterile filtration of protein formulations. To achieve a better insight into this phenomenon, protein adsorption was studied during filtration of stabilized bovine serum albumin (BSA) and γ-globulin formulations through 0.2-µm microfilter membranes by inverse liquid chromatography (ILC). Adsorption processes can be studied with this method by measurement of breakthrough curves. The change of the concentration in the fluid phase is measured with high accuracy by an inline UV-detector.     

Studies on potential of Portland cement mortar for binding of waterworks sludge to reduce heavy metal leaching

The investigation of heavy metal leaching and physicochemical properties of cement-solidified waterworks sludge (CMWWS) formed by incorporating waterworks sludge (WWS) into cement mortar was carried out. The chemical composition, compressive strength and other physicochemical properties of the CMWWS cube specimens were determined using field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD) and Fourier transform-infrared spectroscopy (FTIR). The major type of chemical components present in CMWWS was found to be Al and Fe. The increasing amount of WWS added to cement mortar resulted in the increasing of organic matter, urchin-like morphology and clear peak intensity. At the end of 28 days of curing, the soaking solution became strongly basic and CMWWS cube specimens leached out higher amount of heavy metals. The compressive strength of CMWWS increased up to a WWS percentage of 10%, and basic (pH > 7) curing solution was found to be better than water for curing purposes. It is concluded that solidification–stabilisation (S/S) technique is able to effectively reduce the leaching of heavy metals from the WWS and CMWWS containing up to 10% WWS can be used as construction material.