Biocidal and anti‐corrosive activities of benzoimidazol‐3‐ium cationic Schiff base surfactants

Two series of cationic Schiff base surfactants, namely, 2‐(benzylideneamino)‐3‐(2‐oxo‐2‐alkoxyethyl)‐1,3‐benzoimidazol‐3‐ium bromide (I _A–D ) and 2‐[(4‐methoxybenzylidene) amino]‐3‐(2‐oxo‐2‐alkoxyethyl)‐1,3‐benzoimidazol‐3‐ium bromide (II _A–D ) were prepared. The chemical structures of the prepared Schiff bases were recognized by elemental analysis, FTIR, H NMR, C¹³‐NMR and GC/MS spectra. The surface activities of the synthesized Schiff base cationic surfactants showed their tendency towards adsorption at the air/water interface. The adsorption tendency was estimated from the values of surface tension and the depression of surface tension at the critical micelle concentration. The studied surfactants were evaluated as antimicrobial agents against pathogenic and sulfur‐reducing bacteria using inhibition zone diameters and minimum inhibition concentration values. The synthesized cationic benzoimidazolium Schiff base cationic surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative as well as fungi. The synthesized compounds were tested for the activity as corrosion inhibitors against carbon steel corrosion in 0.5 M HCl at 200 and 400 ppm. The promising inhibition efficiency of these compounds against the sulfur‐reducing bacteria facilitates them to be applicable in the petroleum field as new categories of Sulfur Reducing Bacteria biocides. The inhibition efficiencies of the tested compounds showed good inhibition and protection of the carbon steel. The corrosion inhibition tendency correlated to the surface activity and chemical structure of the compounds.     

Usage of electrostatic eliminator reduces human keratin contamination significantly in gel-based proteomics analysis

In the field of bottom-up proteomics, heavy contamination of human keratins could hinder the comprehensive protein identification, especially for the detection of low abundance proteins. In this study, we examined the keratin contamination in the four major experimental procedures in gel-based proteomic analysis including gel preparation, gel electrophoresis, gel staining, and in-gel digestion. We found that in-gel digestion procedure might be of importance corresponding to keratin contaminants compared to the other three ones. The human keratin contamination was reduced significantly by using an electrostatic eliminator during in-gel digestion, suggesting that static electricity built up on insulated experimental materials might be one of the essential causes of keratin contamination. We herein proposed a series of methods for improving experimental conditions and sample treatment in order to minimize the keratin contamination in an economical and practical way.     

Arsenate replacing phosphate: alternative life chemistries and ion promiscuity

A newly identified bacterial strain that can grow in the presence of arsenate and possibly in the absence of phosphate, has raised much interest, but also fueled an active debate. Can arsenate substitute for phosphate in some or possibly in most of the absolutely essential phosphate-based biomolecules, including DNA? If so, then the possibility of alternative, arsenic-based life forms must be considered. The physicochemical similarity of these two oxyanions speaks in favor of this idea. However, arsenate-esters and arsenate-diesters in particular are extremely unstable in aqueous media. Here, we explore the potential of arsenate to be used as substrate by phosphate-utilizing enzymes. We review the existing literature on arsenate enzymology, that intriguingly, dates back to the 1930s. We address the issue of how and to what degree proteins can distinguish between arsenate and phosphate and what is known in general about oxyanion specificity. We also discuss how phosphate-arsenate promiscuity may affect evolutionary transitions between phosphate- and arsenate-based biochemistry. Finally, we highlight potential applications of arsenate as a structural and mechanistic probe of enzymes whose catalyzed reactions involve the making or breaking of phosphoester bonds.     

Role of chemistry versus substrate binding in recruiting promiscuous enzyme functions

Two different scenarios for the recruitment of evolutionary starting points and their subsequent divergence to give new enzymes have been described. The coincidental, promiscuous starting activity may regard the same reaction chemistry on a new substrate (substrate ambiguity). Alternatively, substrate binding guides the recruitment of an enzyme whose reaction chemistry differs from that of the newly evolving one (catalytic promiscuity). While substrate ambiguity seems to underlie the divergence of most enzyme families, the relative levels of occurrence of these scenarios remain unknown. Screening the Escherichia coli proteome with a comparative series of xenobiotic substrates, we found that substrate ambiguity was, as anticipated, more frequent than reaction promiscuity. However, for at least one unnatural reaction (phosphonoesterase), a promiscuous enzyme was identified only when the substrate was decorated with the naturally abundant phosphate group. These findings support the prevailing hypothesis of chemistry-driven divergence but also suggest that recognition of familiar substrate motifs plays a role. In the absence of enzymes catalyzing the same chemistry, having a familiar, naturally occurring substrate motif (chemophore) such as phosphate may increase the likelihood of catalytic promiscuity. Chemophore anchoring may also find practical applications in identifying catalysts for unnatural reactions.     

Profiling Sirolimus-Induced Inflammatory Syndrome: A Prospective Tricentric Observational Study

Background

The use of the immunosuppressant sirolimus in kidney transplantation has been made problematic by the frequent occurrence of various side effects, including paradoxical inflammatory manifestations, the pathophysiology of which has remained elusive.

Methods

30 kidney transplant recipients that required a switch from calcineurin inhibitor to sirolimus-based immunosuppression, were prospectively followed for 3 months. Inflammatory symptoms were quantified by the patients using visual analogue scales and serum samples were collected before, 15, 30, and 90 days after the switch.

Results

66% of patients reported at least 1 inflammatory symptom, cutaneo-mucosal manifestations being the most frequent. Inflammatory symptoms were characterized by their lability and stochastic nature, each patient exhibiting a unique clinical presentation. The biochemical profile was more uniform with a drop of hemoglobin and a concomitant rise of inflammatory acute phase proteins, which peaked in the serum 1 month after the switch. Analyzing the impact of sirolimus introduction on cytokine microenvironment, we observed an increase of IL6 and TNFα without compensation of the negative feedback loops dependent on IL10 and soluble TNF receptors. IL6 and TNFα changes correlated with the intensity of biochemical and clinical inflammatory manifestations in a linear regression model.

Conclusions

Sirolimus triggers a destabilization of the inflammatory cytokine balance in transplanted patients that promotes a paradoxical inflammatory response with mild stochastic clinical symptoms in the weeks following drug introduction. This pathophysiologic mechanism unifies the various individual inflammatory side effects recurrently reported with sirolimus suggesting that they should be considered as a single syndromic entity.     

Bioluminescent Imaging and Histopathologic Characterization of WEEV Neuroinvasion in Outbred CD-1 Mice

Western equine encephalitis virus (WEEV; Alphavirus) is a mosquito-borne virus that can cause severe encephalitis in humans and equids. Previous studies have shown that intranasal infection of outbred CD-1 mice with the WEEV McMillan (McM) strain result in high mortality within 4 days of infection. Here in vivo and ex vivo bioluminescence (BLM) imaging was applied on mice intranasally infected with a recombinant McM virus expressing firefly luciferase (FLUC) to track viral neuroinvasion by FLUC detection and determine any correlation between BLM and viral titer. Immunological markers of disease (MCP-1 and IP-10) were measured and compared to wild type virus infection. Histopathology was guided by corresponding BLM images, and showed that neuroinvasion occurred primarily through cranial nerves, mainly in the olfactory tract. Olfactory bulb neurons were initially infected with subsequent spread of the infection into different regions of the brain. WEEV distribution was confirmed by immunohistochemistry as having marked neuronal infection but very few infected glial cells. Axons displayed infection patterns consistent with viral dissemination along the neuronal axis. The trigeminal nerve served as an additional route of neuroinvasion showing significant FLUC expression within the brainstem. The recombinant virus WEEV.McM.FLUC had attenuated replication kinetics and induced a weaker immunological response than WEEV.McM but produced comparable pathologies. Immunohistochemistry staining for FLUC and WEEV antigen showed that transgene expression was present in all areas of the CNS where virus was observed. BLM provides a quantifiable measure of alphaviral neural disease progression and a method for evaluating antiviral strategies.     

Increase of the Bacillus thuringiensis Secreted Toxicity Against Lepidopteron Larvae by Homologous Expression of the vip3LB Gene During Sporulation Stage

The Vegetative insecticidal Vip3A proteins display a wide range of insecticidal spectrum against several agricultural insect pests. The fact that the expression of vip3 genes occurs only during the vegetative growth phase of Bacillus thuringiensis is a limiting factor in term of production level. Therefore, extending the synthesis of the Vip proteins to the sporulation phase is a good alternative to reach high levels of toxin synthesis. In this study, we have demonstrated that the maximal production of the secreted Vip3LB (also called Vip3Aa16) during the growth of the wild-type strain B. thuringiensis BUPM 95 is reached at the end of the vegetative growth phase, and that the protein remains relatively stable in the culture supernatant during the late sporulation stages. The vip3LB gene was cloned and expressed under the control of the sporulation dependant promoters BtI and BtII in B. thuringiensis BUPM 106 (Vip3(-)) and BUPM 95 (Vip3(+)) strains. The examination of the culture supernatants during the sporulation phase evidenced the synthesis of Vip3LB and its toxicity against the second-instars larvae of the Lepidopteron insect Spodoptera littoralis for the recombinant BUPM 106. Moreover, there was an increase of the Vip3LB synthesis level and an enhancement of the oral toxicity for the recombinant BUPM 95 resulting from the expression of the vip3LB gene during both the vegetative and sporulation phases and the relative stability of the Vip3LB protein.     

Discovery of fused bicyclic agonists of the orphan G-protein coupled receptor GPR119 with in vivo activity in rodent models of glucose control

We herein outline the design of a new series of agonists of the pancreatic and GI-expressed orphan G-protein coupled receptor GPR119, a target that has been of significant recent interest in the field of metabolism, starting from our prototypical agonist AR231453. A number of key parameters were improved first by incorporation of a pyrazolopyrimidine core to create a new structural series and secondly by the introduction of a piperidine ether group capped with a carbamate. Chronic treatment with one compound from the series, 3k, showed for the first time that blood glucose and glycated hemoglobin (HbA1c) levels could be significantly reduced in Zucker Diabetic Fatty (ZDF) rats over several weeks of dosing. As a result of these and other data described here, 3k (APD668, JNJ-28630368) was the first compound with this mechanism of action to be progressed into clinical development for the treatment of diabetes.     

New inhibitors of VEGFR-2 targeting the extracellular domain dimerization process

We are reporting the discovery of small molecule inhibitors for vascular endothelial growth factor receptor type 2 (VEGFR-2) extracellular domain. The VEGFR-2 extracellular domain is responsible for the homo-dimerization process, which has been recently reported as a main step in VEGFR signal transduction cascade. This cascade is essential for the vascularization and survival of most types of cancers. Two main design strategies were used; Molecular docking-based Virtual Screening and Fragment Based Design (FBD). A virtual library of drug like compounds was screened using a cascade of docking techniques in order to discover an inhibitor that binds to this new binding site. Rapid docking methodology was used first to filter the large number of compounds followed by more accurate and slow ones. Fragment based molecular design was adopted afterwards due to unsatisfactory results of screening process. Screening and design process resulted in a group of inhibitors with superior binding energies exceeding that of the natural substrate. Molecular dynamics simulation was used to test the stability of binding of these inhibitors and finally the drug ability of these compounds was assisted using Lipinski rule of five. By this way the designed compounds have shown to possess high pharmacologic potential as novel anticancer agents.