Surfactant therapy for patients with ARDS after cardiac surgery

This multicenter study investigated the possibility of reducing mortality rate by administering natural lung surfactant additional to standard therapy to treat patients after cardiac surgery who developed an acute respiratory failure (ARDS/ALI).A total of 78 patients (1998-2002) diagnosed with ALI or ARDS were enrolled in the study; patients were considered for study entry only if they developed ALI/ARDS within 72 h after cardiac surgery. A total of 36 patients (2000-2002) received Surfactant-BL via bronchoscope at a dose of 3 mg/kg twice a day, and 42 patients (1998-2000) served as the historical control.Within 24 h after the first Surfactant-BL administration the PaO2/FiO2 ratio increased from (mean+/-SEM) 129.7+/-9.9 mm Hg to 187.6+/-17.6 mm Hg (p<0.01), FiO2 decreased from (mean+/-SEM) 0.71+/-0.03 to 0.56+/-0.03 (p<0.01), and 69.4% of the patients treated with surfactant were weaned from the ventilator compared with 50% of the control group during a 28-day period. The mortality rate among patients treated with Surfactant-BL was 30.6% compared with 50% in the control group.In conclusion, early administration of Surfactant-BL leads to the reduction of mortality in cardiac patients who develop postoperatively an ALI or ARDS.     

Investigation of selective protein immobilization on charged protein array by wavelength interrogation-based SPR sensor

We have investigated the use of multilayer films of polyelectrolytes as selective surfaces to analyze protein interactions with a self-assembled SPR wavelength-shift sensor. Charged arrays were prepared by alternating adsorption of the charged polyelectrolytes, poly(diallyldimethylammonium chloride) (PDDA) and poly(sodium 4-styrenesulfonate) (PSS). Multilayer formation was monitored with the SPR wavelength-shift sensor and a Spreeta SPR sensor. Protein immobilization on the charged surfaces, which was also analyzed by the SPR sensors, was dependent on the pI of the proteins. Tissue transglutaminase (tTGase) and beta-galactosidase (pIs, 5.1 and 5.3, respectively) were preferentially bound to the positively charged PDDA surface, whereas lysozyme (pI, 11.0) was selectively bound to the negatively charged PSS surface. Immobilization of tTGase on the PDDA surface was also dependent on the buffer pH. The interaction of tTGase with RhoA(V14), a constitutively active form of Rho, could be detected on the charged arrays with the wavelength-shift sensor. The arrays could be reutilized at least 5 times. Thus, it is likely that charged surfaces, assembled by the layer-by-layer method using polyelectrolytes, will prove useful for preparing selective protein arrays.     

Functional expression of an ajmaline pathway-specific esterase from <Emphasis Type="Italic">Rauvolfia</Emphasis> in a novel plant-virus expression system

Acetylajmalan esterase (AAE) plays an essential role in the late stage of ajmaline biosynthesis. Based on the partial peptide sequences of AAE isolated and purified from Rauvolfia cell suspensions, a full-length AAE cDNA clone was isolated. The amino acid sequence of AAE has the highest level of identity of 40% to putative lipases known from the Arabidopsis thaliana genome project. Based on the primary structure AAE is a new member of the GDSL lipase superfamily. The expression in Escherichia coli failed although a wide range of conditions were tested. With a novel virus-based plant expression system, it was possible to express AAE functionally in leaves of Nicotiana benthamiana Domin. An extraordinarily high enzyme activity was detected in the Nicotiana tissue, which exceeded that in Rauvolfia serpentina (L.) Benth. ex Kurz cell suspension cultures about 20-fold. This expression allowed molecular analysis of AAE for the first time and increased the number of functionally expressed alkaloid genes from Rauvolfia now to eight, and the number of ajmaline pathway-specific cDNAs to a total of six. The nucleotide sequence reported in this article has been submitted to the GenBank/EBI under GenBank Accession no. AY762990     

Open and compressed conformations of Francisella tularensis ClpP

Caseinolytic proteases are large oligomeric assemblies responsible for maintaining protein homeostasis in bacteria and in so doing influence a wide range of biological processes. The functional assembly involves three chaperones together with the oligomeric caseinolytic protease catalytic subunit P (ClpP). This protease represents a potential target for therapeutic intervention in pathogenic bacteria. Here, we detail an efficient protocol for production of recombinant ClpP from Francisella tularensis, and the structural characterization of three crystal forms which grow under similar conditions. One crystal form reveals a compressed state of the ClpP tetradecamer and two forms an open state. A comparison of the two types of structure infers that differences at the enzyme active site result from a conformational change involving a highly localized disorder‐order transition of a β‐strand α‐helix combination. This transition occurs at a subunit‐subunit interface. Our study may now underpin future efforts in a structure‐based approach to target ClpP for inhibitor or activator development. Proteins 2016; 85:188–194. © 2016 Wiley Periodicals, Inc.     

Hollandite‐Type VO1.75(OH)0.5: Effective Sodium Storage for High‐Performance Sodium‐Ion Batteries

Nanosized hollandite‐type VO_1.75(OH)_0.5 is introduced as a novel cathode material for Na‐ion batteries. Structural investigation based on X‐ray diffraction and Rietveld refinement suggests the presence of numerous vacant sites for Na⁺ intercalation in the VO_1.75(OH)_0.5 structure. All of the possible Na⁺ sites and tunnel‐type Na⁺ diffusion pathways along the c‐axis are confirmed by bond‐valence‐sum analyses. The nanosized hollandite‐type VO_1.75(OH)_0.5 delivers an unexpectedly high specific capacity of ≈351 mAh g^?1 at 15.5 mA g^?1 in the voltage range of 1.0–3.7 V (vs Na⁺/Na), which agrees well with the results predicted by first‐principles calculations. In addition, combined studies using first‐principles calculations and several experimental techniques including in situ operando X‐ray diffraction and ex situ X‐ray absorption spectroscopy confirm that the nanosized hollandite‐type VO_1.75(OH)_0.5 undergoes a single‐phase reaction with a capacity retention of 71% over 200 cycles. Furthermore, the open structure and nanosized particles of hollandite‐type VO_1.75(OH)_0.5 contribute to its excellent power capability with 56% of the capacity measured at 0.05 C being delivered at 7 C.     

Surfactant Therapy for Patients with ARDS After Cardiac Surgery

This multicenter study investigated the possibility of reducing mortality rate by administering natural lung surfactant additional to standard therapy to treat patients after cardiac surgery who developed an acute respiratory failure (ARDS/ALI).

A total of 78 patients (1998–2002) diagnosed with ALI or ARDS were enrolled in the study; patients were considered for study entry only if they developed ALI/ARDS within 72h after cardiac surgery. A total of 36 patients (2000–2002) received Surfactant-BL via bronchoscope at a dose of 3 mg/kg twice a day, and 42 patients (1998–2000) served as the historical control.

Within 24h after the first Surfactant-BL administration the PaO₂/FiO₂ ratio increased from (mean ± SEM) 129.7 ± 9.9 mm Hg to 187.6 ± 17.6 mm Hg (p < 0.01), FiO₂ decreased from (mean ± SEM) 0.71 ± 0.03 to 0.56 ± 0.03 (p < 0.01), and 69.4% of the patients treated with surfactant were weaned from the ventilator compared with 50% of the control group during a 28-day period. The mortality rate among patients treated with Surfactant-BL was 30.6% compared with 50% in the control group.

In conclusion, early administration of Surfactant-BL leads to the reduction of mortality in cardiac patients who develop postoperatively an ALI or ARDS.     

Processing of VSVG protein is not a rate-limiting step for its efflux from the Golgi complex

The secretory membrane system is comprised of membrane-bound organelles defined by specific sets of proteins that function in sequential modification of cargo proteins and lipids. This processing of cargo proteins and lipids is coupled to their secretory transport. Here, we investigated the effect of inhibiting N-glycan processing by swainsonine, an inhibitor of Golgi alpha1,2-mannosidase-II, on secretory transport of the thermo-reversible tsO45 mutant of vesicular stomatitis virus glycoprotein tagged with green fluorescent protein (VSVG-FP). Quantitative analysis using kinetic modeling combined with live cell imaging was used to derive the rate coefficients that delineate secretory transport of VSVG-FP. We found that neither inhibition of N-glycan processing nor elimination by mutagenesis of the first of the two asparagine-linked glycans had any significant effect on the rate of VSVG-FP transport through the Golgi. These data suggest that at least for VSVG, the multi-enzymatic process of N-glycan modification does not comprise a rate-limiting step for its Golgi efflux.