High incorporation of L-amino acids to cereulide, an emetic toxin from Bacillus cereus

Cereulide is a principal toxin causing emetic syndrome produced by Bacillus cereus. This paper deals with biosynthetic studies on this unusual cyclic depsipeptide toxin from 13C labeled L-amino acid precursors (Val, Leu, Ala) upon cultivation in synthetic media. The analyses were made at atomic level of the constituent amino- or oxy-acids through NMR and ESI-MS/MS spectroscopic methods on cereulide and its hydrolysate dipeptides. The incorporation of the 13C atom was 95% in each O-Val, O-Leu and L-Val, while 40% in D-Ala of cereulide.     

The 712A/G polymorphism of Brain-derived neurotrophic factor is associated with Parkinson's disease but not Major Depressive Disorder in a Chinese Han population

Background: Overlaps in clinical, pathological and molecular characteristics of Parkinson’s disease (PD) and Major Depressive Disorder (MD-D) have promoted association studies in search of common genetic risk factors that may predispose or modify this spectrum of disorders. Experimental and clinical data suggest that genetic variations in Brain-derived neurotrophic factor (BDNF) gene may increase the risk for PD and MD-D. Methods: Two hundred and sixty-six PD, 83 MD-D and 400 controls were recruited for this study, assessed using a battery of neuropsychological tests, and genotyped for 11757C/G, 712A/G, 196A/G, and 270C/T in BDNF gene. Results: 712A/G was associated with 2.50-fold time risk of PD. By combining genotypes AG/AA with 712 GG genotype as reference (OR = 1) in stratification analysis, AG/AA genotypes were associated with PD (OR = 2.94, 95% CI = 1.88–4.61). Accordingly, the A allele was significantly overrepresented in PD compared with the G allele (OR = 3.16, 95% CI = 2.08–4.81). This distribution in females and males were similar. Conclusion: Our results suggested a novel association between BDNF 712A/G AG/AA genotypes and PD in a Chinese Han population.     

Bio-electrosprays: the next generation of electrified jets

Biological electrosprays are rapidly becoming a robust means by which to engineer living organisms for applications ranging from tissue repair to developmental biology. We previously reported the ability to electrospray living organisms without compromising their viability, but found it challenging to achieve stability in the jetting of these organisms as a result of the chemical properties of the living cellular suspensions. Jet stability is required for the generation of a near-mono distribution of droplets, which is necessary for the development of electrospray technology as a "drop and place" biotechnique. Recently, we determined the conditions needed to achieve jet stability and were able to generate droplets with a near-mono distribution (<50 microm). In this communication, we elucidate the relationship between jet behaviour and droplet size under stable jetting conditions, with a view to further reducing the droplet size to deposit a single living cell within a droplet. We believe that this level of resolution will make electrospray jetting superior amongst the jet-based biotechnologies presently being developed for the engineering of biological architectures comprised of living cells.     

One-step purification and immobilization of thermophilic polyphosphate glucokinase from <Emphasis Type="BoldItalic">Thermobifida fusca</Emphasis> YX: glucose-6-phosphate generation without ATP

The discovery of stable and active polyphosphate glucokinase (PPGK, EC 2.7.1.63) would be vital to cascade enzyme biocatalysis that does not require a costly ATP input. An open reading frame Tfu_1811 from Thermobifida fusca YX encoding a putative PPGK was cloned and the recombinant protein fused with a family 3 cellulose-binding module (CBM-PPGK) was overexpressed in Escherichia coli. Mg²⁺ was an indispensible activator. This enzyme exhibited the highest activity in the presence of 4 mM Mg²⁺ at 55°C and pH 9.0. Under its suboptimal conditions (pH 7.5), the k _cat and K _m values of CBM-PPGK on glucose were 96.9 and 39.7 s⁻¹ as well as 0.77 and 0.45 mM at 37°C and 50°C respectively. The thermoinactivation of CBM-PPGK was independent of its mass concentration. Through one-step enzyme purification and immobilization on a high-capacity regenerated amorphous cellulose, immobilized CBM-PPGK had an approximately eightfold half lifetime enhancement (i.e., t _1/2 = 120 min) as compared to free enzyme at 50°C. To our limited knowledge, this enzyme was the first thermostable PPGK reported. Free PPGK and immobilized CBM-PPGK had total turnover number values of 126,000 and 961,000 mol product per mol enzyme, respectively, suggesting their great potential in glucose-6-phosphate generation based on low-cost polyphosphate.     

Aerodynamically assisted jetting and threading for processing concentrated suspensions containing advanced structural,functional and biological materials

In recent years material sciences have been interpreted right across the physical and the life sciences. Essentially this discipline broadly addresses the materials, processing, and/or fabrication right up to the structure. The materials and structures areas can range from the micro- to the nanometre scale and, in a materials sense, span from the structural, functional to the most complex, namely biological (living cells). It is generally recognised that the processing or fabrication is fundamental in bridging the materials with their structures. In a global perspective, processing has not only contributed to the materials sciences but its very nature has bridged the physical with the life sciences. In this review we discuss one such swiftly emerging fabrication approach having a plethora of applications spanning the physical and life sciences.     

A unique physical-chemistry approach for fabricating cell friendly surfaces

Recent interests in the fabrication of bio/cell-friendly surfaces are consistently gaining much scientific coverage as these methods could be explored as novel regenerative and therapeutic medicinal protocols. Essentially two main components govern this aspect, the processing methodology possessing the required robustness to fabricate a wide range of materials and, not least, the synthesised materials that need to be cell-compatible both in the short and long term after processing. In the study reported here we have combined one such robust jetting approach with a specially formulated siloxane sol. This has several unique properties in itself, and these have been demonstrated here to have a positive effect on the seeded cells. The current work demonstrates that this approach has great promise as a novel methodology for surface engineering for a wide range of applications spanning the physical to the life science areas of research.     

Gene expression studies on bio-electrosprayed primary cardiac myocytes

Cardiovascular pathology accounts for the greatest number of mortalities in the western world and thus the development of ex vivo cardiac tissue has vast potential in cardiac therapy. Bio-electrosprays (BES), a recently discovered direct cell engineering protocol, has demonstrated tremendous applicability for regenerative and therapeutic medicine. For bio-electrospraying to be carried forward as a novel method of cardiac tissue engineering, it is important that the process does not adversely affect cellular physiology. Our previous work has shown that bio-electrospraying does not induce cell death, activate intracellular stress pathways or induce DNA damage in primary cardiac myocytes. Here we show for the first time using genome-wide microarray analysis, that bio-electrospraying has no negative effects on global gene expression in cardiac myocytes. Moreover, we show that bio-electrospraying does not lead to endothelial cell activation. These data suggest that BES has minimal effect upon the physiology of cardiac myocytes and endothelial cells and thus paves the way for the development of BES in cardiac tissue engineering.