Full recovery of a patient after oxygenator replacement during open-heart surgery

During an open-heart procedure in a 69-year-old man, a damaged mitral valve was being examined when suddenly the venous return line from the oxygenator of the heart-lung machine became filled with gas. After the venous line had been flushed and cardiopulmonary bypass had been reinstated, the line again filled with gas, and the aortic line also had to be clamped to prevent a massive air embolism. The oxygenator was immediately exchanged, bypass was resumed after 7 to 8 minutes, and the surgical procedures were completed. The patient survived, and a year and a half later continues in good health. His survival was attributed to three factors: intraaortic balloon support, hypothermia to 28 degrees C, and the prompt exchange of oxygenators.     

Resistance and resilience of root fungal communities to water limitation in a temperate agroecosystem

Understanding crop resilience to environmental stress is critical in predicting the consequences of global climate change for agricultural systems worldwide, but to date studies addressing crop resiliency have focused primarily on plant physiological and molecular responses. Arbuscular mycorrhizal fungi (AMF) form mutualisms with many crop species, and these relationships are key in mitigating the effects of abiotic stress in many agricultural systems. However, to date there is little research examining whether (1) fungal community structure in agroecosystems is resistant to changing environmental conditions, specifically water limitation and (2) resilience of fungal community structure is moderated by agricultural management systems, namely the integration of trees into cropping systems. Here, we address these uncertainties through a rainfall reduction field experiment that manipulated short‐term water availability in a soybean‐based (Glycine max L. Merr.) agroforest in Southern Ontario, Canada. We employed terminal restriction fragment length polymorphism analysis to determine the molecular diversity of both general fungal and AMF communities in soybean roots under no stress, stress (rainfall shelters added), and poststress (rainfall shelters removed). We found that general fungal and AMF communities sampled from soybean roots were resistant to rainfall reduction in a monoculture, but not in an agroforest. While AMF communities were unchanged after stress removal, general fungal communities were significantly different poststress in the agroforest, indicating a capacity for resiliency. Our study indicates that generalist fungi and AMF are responsive to changes in environmental conditions and that agroecosystem management plays a key role in the resistance and resilience of fungal communities to water limitation.     

Photoluminescence properties of LiTi2 − xEux(PO4)3 phosphor

A solid‐state reaction route‐based LiTi_{2 ? x}Eu_x(PO₄)₃ was phosphor synthesized for the first time to evaluate its luminescence performance by excitation, emission and lifetime (τ) measurements. The LiTi_{2 ? x}Eu_x(PO₄)₃ phosphor was excited at λ_exci. = 397 nm to give an intense orange–red (597 nm) emission attributed to the ⁵D₀ → ⁷F₁ magnetic dipole (ΔJ = ±1) transition and red (616 nm) emission (⁵D₀ → ⁷F₂), which is an electric dipole (ΔJ = ±2) transition of the Eu³⁺ ion. Beside this, excitation and emission spectra of host LiTi₂(PO₄)₃ powder were also reported. The effect of Eu³⁺ concentration on luminescence characteristics was explained from emission and lifetime profiles. Concentration quenching in the LiTi_{2 ? x}Eu_x(PO₄)₃ phosphor was studied from the Dexter's model. Dipole–quadrupole interaction is found to be responsible for energy transfer among Eu³⁺ ions in the host lattice. The LiTi_{2 ? x}Eu_x(PO₄)₃ phosphor displayed a reddish‐orange colour realized from a CIE chromaticity diagram. We therefore suggest that this new phosphor could be used as an optical material of technological importance in the field of display devices. Copyright © 2016 John Wiley & Sons, Ltd.     

Identification of essential loops and residues of glucosyltransferase V (GtrV) of Shigella flexneri

Lipopolysaccharide (LPS), particularly the O-antigen component, is one of many virulence determinants necessary for Shigella flexneri pathogenesis. O-antigen modification is mediated by glucosyltransferase (gtr) genes encoded by temperate serotype-converting bacteriophages. The gtrV and gtrX genes encode the GtrV and GtrX glucosyltransferases, respectively. These are integral membrane proteins, which catalyze the transfer of a glucosyl residue via an alpha1,3 linkage to rhamnose II and rhamnose I of the O-antigen unit. This mediates conversion of S. flexneri serotype Y to serotype 5a and X, respectively. Essential regions in the topology of GtrV protein were identified by in vivo recombination and a PCR-mediated approach. A series of GtrX-GtrV and GtrV-GtrX chimeric proteins were constructed based on the fact that GtrV and GtrX share sequence similarity. Analysis of their respective serotype conversion abilities led to the identification of two important periplasmic loops: loops No 2 and No 10 located in the N- and C-termini, respectively. Within these two loops, three conserved motifs were identified; two in loop No 2 and one in loop No 10. These conserved motifs contain acidic residues which were shown to be critical for GtrV function.     

2-Ketogluconic Acid Secretion by Incorporation of Pseudomonas putida KT 2440 Gluconate Dehydrogenase (gad) Operon in Enterobacter asburiae PSI3 Improves Mineral Phosphate Solubilization

Enterobacter asburiae PSI3 is known to efficiently solubilize rock phosphate by secretion of approximately 50 mM gluconic acid in Tris-buffered medium in the presence of 75 mM glucose and in a mixture of seven aldosugars each at 15 mM concentration, mimicking alkaline vertisol soils. Efficacy of this bacterium in the rhizosphere requires P release in the presence of low amount of sugars. To achieve this, E. asburiae PSI3 has been manipulated to express gluconate dehydrogenase (gad) operon of Pseudomonas putida KT 2440 to produce 2-ketogluconic acid. E. asburiae PSI3 harboring gad operon had 438 U of GAD activity, secreted 11.63 mM 2-ketogluconic and 21.65 mM gluconic acids in Tris-rock phosphate-buffered medium containing 45 mM glucose. E. asburiae PSI3 gad transformant solubilized 0.84 mM P from rock phosphate in TRP-buffered liquid medium. In the presence of a mixture of seven sugars each at 12 mM, the transformant brought about a drop in pH to 4.1 and released 0.53 mM P.     

Ibuprofen loading and release in amphiphilic peptide FA32 and its derivatives: a coarse-grained molecular dynamics simulation study

A molecular dynamics simulation study is reported to investigate the loading and release of ibuprofen (IBU) in amphiphilic peptide (AF)₆H₅K₁₅ (FA32) and its derivatives (F₁₂H₅K₁₅ and F₁₆H₅K₁₅). The peptides are represented by the MARTINI coarse-grained model, and a similar model is developed here for IBU. Upon the loading of IBU in FA32, quasi-spherical core/shell structured micelles are formed. IBU is predominantly located in the hydrophobic core and covered by Phe and Ala residues, while Lys is in the hydrophilic shell. With increasing concentration of IBU, the micelles become larger due to increased hydrophobic interactions. In FA32 derivatives, the loading of IBU leads to different morphologies; particularly, a well-structured nanofibre is formed in F₁₆H₅K₁₅. Upon pH change, the release of IBU from FA32 micelles is found to be slower than from F₁₆H₅K₁₅ nanofibre, suggesting the former is better in controlled release. The simulation study reveals that IBU-loaded morphology can be altered by changing the type of peptide and has a significant effect on IBU release profile. This bottom-up insight might be useful in the rational design of carriers for efficient drug loading and release.