Identification and quantitation of usnic acid from the lichen Usnea species of Anatolia and antimicrobial activity

Six species of lichens, such as Usnea florida, Usnea barbata, Usnea longissima, Usnea rigida, Usnea hirta and Usnea subflorida, were collected from different areas of Anatolia (district of Antalya, Karabük, Qankiri, Giresun and Trabzon) in Turkey. Their usnic acid amounts in acetone extracts were determined by HPLC. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis and Bacillus megaterium. It was shown that with increasing amount of usnic acid, the antimicrobial activity increased. Usnic acid contents of Usnea species varied between 0.22-6.49% of dry weight.     

Fabrication of hierarchical hybrid structures using bio-enabled layer-by-layer self-assembly

Development of versatile and flexible assembly systems for fabrication of functional hybrid nanomaterials with well-defined hierarchical and spatial organization is of a significant importance in practical nanobiotechnology applications. Here we demonstrate a bio-enabled self-assembly technique for fabrication of multi-layered protein and nanometallic assemblies utilizing a modular gold-binding (AuBP1) fusion tag. To accomplish the bottom-up assembly we first genetically fused the AuBP1 peptide sequence to the C'-terminus of maltose-binding protein (MBP) using two different linkers to produce MBP-AuBP1 hetero-functional constructs. Using various spectroscopic techniques, surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR), we verified the exceptional binding and self-assembly characteristics of AuBP1 peptide. The AuBP1 peptide tag can direct the organization of recombinant MBP protein on various gold surfaces through an efficient control of the organic-inorganic interface at the molecular level. Furthermore using a combination of soft-lithography, self-assembly techniques and advanced AuBP1 peptide tag technology, we produced spatially and hierarchically controlled protein multi-layered assemblies on gold nanoparticle arrays with high molecular packing density and pattering efficiency in simple, reproducible steps. This model system offers layer-by-layer assembly capability based on specific AuBP1 peptide tag and constitutes novel biological routes for biofabrication of various protein arrays, plasmon-active nanometallic assemblies and devices with controlled organization, packing density and architecture.     

Eicosanoids mediate melanotic nodulation reactions to viral infection in larvae of the parasitic wasp, Pimpla turionellae

Nodulation is the quantitatively predominant insect cellular immune function activated in response to bacterial, fungal and some viral infections. We posed the hypothesis that parasitoid insects express melanotic nodulation reactions to viral challenge and that eicosanoids mediate these reactions. Treating fifth-instar larvae of the ichneumonid endoparasitoid Pimpla turionellae with Bovine Herpes Simplex Virus-1 (BHSV-1) induced nodulation reactions in a challenge dose-dependent manner. Experimental larvae treated with the cyclooxygenase inhibitor, indomethacin, the lipoxygenase inhibitor, esculetin, and the phospholipase A2 inhibitor, dexamethasone, resulted in severely impaired nodulation reactions to our standard BHSV-1 challenge dose. The immunoinhibitory influence of dexamethasone was reversed in larvae reared on culture medium amended with arachidonic acid, the fatty acid precursor of eicosanoid biosynthesis. Larvae that had been reared on media amended with indomethacin, esculetin, or dexamethasone were also compromised in their nodulation reactions to viral challenge. The influence of the orally administered pharmaceutical was expressed in a dose-dependent manner. Finally, wasp larvae reared in the presence of indomethacin and dexamethasone expressed significantly decreased levels of phenoloxidase activity in response to viral challenge. These findings draw attention to the idea that endoparasitoid insects express cellular immune reactions to viral challenge; they also support our hypothesis that eicosanoids mediate nodulation reactions to viral challenge in these highly specialized insects.     

Wall stress and flow dynamics in abdominal aortic aneurysms: finite element analysis vs. fluid-structure interaction

Abdominal aortic aneurysm (AAA) rupture is the clinical manifestation of an induced force exceeding the resistance provided by the strength of the arterial wall. This force is most frequently assumed to be the product of a uniform luminal pressure acting along the diseased wall. However fluid dynamics is a known contributor to the pathogenesis of AAAs, and the dynamic interaction of blood flow and the arterial wall represents the in vivo environment at the macro-scale. The primary objective of this investigation is to assess the significance of assuming an arbitrary estimated peak fluid pressure inside the aneurysm sac for the evaluation of AAA wall mechanics, as compared with the non-uniform pressure resulting from a coupled fluid-structure interaction (FSI) analysis. In addition, a finite element approach is utilised to estimate the effects of asymmetry and wall thickness on the wall stress and fluid dynamics of ten idealised AAA models and one non-aneurysmal control. Five degrees of asymmetry with uniform and variable wall thickness are used. Each was modelled under a static pressure-deformation analysis, as well as a transient FSI. The results show that the inclusion of fluid flow yields a maximum AAA wall stress up to 20% higher compared to that obtained with a static wall stress analysis with an assumed peak luminal pressure of 117 mmHg. The variable wall models have a maximum wall stress nearly four times that of a uniform wall thickness, and also increasing with asymmetry in both instances. The inclusion of an axial stretch and external pressure to the computational domain decreases the wall stress by 17%.     

Therapeutic administration of anti-PcrV F(ab')(2) in sepsis associated with Pseudomonas aeruginosa.

The effects of rabbit-derived polyclonal Ab against PcrV, a protein involved in the translocation of type III secreted toxins of Pseudomonas aeruginosa, was investigated in two animal models of P. aeruginosa sepsis. In a mouse survival study, the i.v. administration of anti-PcrV IgG after the airspace instillation of a lethal dose of P. aeruginosa resulted in the complete survival of the animals. In a rabbit model of septic shock associated with Pseudomonas-induced lung injury, animals treated with anti-PcrV IgG intratracheally or i.v. had significant decreases in lung injury, bacteremia, and plasma TNF-alpha and significant improvement in the hemodynamic parameters associated with shock compared with animals treated in a similar manner with nonspecific control IgG. The administration of anti-PcrV F(ab')(2) showed protective effects comparable to those of whole anti-PcrV IgG. These results document that the therapeutic administration of anti-PcrV IgG blocks the type III secretion system-mediated virulence of P. aeruginosa and prevents septic shock and death, and that these protective effects are largely Fc independent. We conclude that Ab therapy neutralizing the type III secretion system has significant potential against lethal P. aeruginosa infections.     

Effects of ferrous iron on the performance and microbial community in aerobic granular sludge in relation to nutrient removal

Lab‐scale experiments were conducted to investigate the effects of ferrous iron on nutrient removal performance and variations in the microbial community inside aerobic granular sludge for 408 days. Two reactors were simultaneously operated, one without added ferrous iron (SBR1), and one with 10 mg Fe²⁺ L^?1 of added ferrous iron (SBR2). A total of 1 mg Fe²⁺ L^?1 of added ferrous iron was applied to SBR1 starting from the 191st day to observe the resulting variations in the nutrient removal performance and the microbial community. The results show that ammonia‐oxidizing bacteria (AOB) could not oxidize ammonia due to a lack of iron compounds, but they could survive in the aerobic granular sludge. Limited ferrous iron addition encouraged nitrification. Enhanced biological phosphorus removal (EBPR) from both reactors could not be maintained regardless of the amount of ferrous iron that was applied. EBPR was established in both reactors when the concentration of mixed liquor suspended solid (MLSS) and the percentage of Accumulibacteria increased. A total of 10 mg Fe²⁺ L^?1 of added ferrous iron had a relatively adverse effect on the growth of AOB species compared to 1 mg Fe²⁺ L^?1 of added ferrous iron, but it encouraged the growth of Nitrospira sp. and Accumulibacteria, which requires further study. It could be said that the compact and stable structure of aerobic granular sludge preserved AOB and NOB from Fe‐deficient conditions, and wash‐out during the disintegration period. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:716–725, 2017