Characterization of the ApoLp-III/LPS Complex: Insight into the Mode of Binding Interaction

Apolipoproteins are able to associate with lipopolysaccharides (LPS), potentially providing protection against septic shock. To gain insight into the molecular details of this binding interaction, apolipophorin III (apoLp-III) from Galleria mellonella was used as a model. The binding of apoLp-III to LPS was optimal around 37-40 °C, close to the LPS phase transition temperature. ApoLp-III formed complexes with LPS from E. coli (serotype O55:B5) with a diameter of ～20 nm and a molecular weight of ～390 kDa, containing four molecules of apoLp-III and 24 molecules of LPS. The LPS-bound form of the protein was substantially more resistant to guanidine-induced denaturation compared to unbound protein. The denaturation profile displayed a multiphase character with a steep drop in secondary structure between 0 and 1 M guanidine-HCl and a slower decrease above 1 M guanidine-HCl. In contrast, apoLp-III bound to detoxified LPS was only slightly more resistant to guanidine-HCl induced denaturation compared to unbound protein. Analysis of size-exclusion FPLC elution profiles of mixtures of apoLp-III with LPS or detoxified LPS indicated a much weaker binding interaction with detoxified LPS compared to intact LPS. These results indicate that apoLp-III initially interacts with exposed carbohydrate regions, but that the lipid A region is required for a more stable LPS binding interaction.     

Immune responses in multiple hosts to Nucleocapsid Protein (NP) of Crimean-Congo Hemorrhagic Fever Virus (CCHFV)

In 2019, the World Health Organization declared 3 billion to be at risk of developing Crimean Congo Hemorrhagic Fever (CCHF). The causative agent of this deadly infection is CCHFV. The data related to the biology and immunology of CCHFV are rather scarce. Due to its indispensable roles in the viral life cycle, NP becomes a logical target for detailed viral immunology studies. In this study, humoral immunity to NP was investigated in CCHF survivors, as well as in immunized mice and rabbits. Abundant antibody response against NP was demonstrated both during natural infection in humans and following experimental immunizations in mice and rabbits. Also, cellular immune responses to recombinant NP (rNP) was detected in multispecies. This study represents the most comprehensive investigation on NP as an inducer of both humoral and cellular immunity in multiple hosts and proves that rNP is an excellent candidate warranting further immunological studies specifically on vaccine investigations.     

Spatiotemporal remodeling of embryonic aortic arch: stress distribution,microstructure, and vascular growth in silico

Biomechanics and Modeling in Mechanobiology - The microstructure for mature vessels has been investigated in detail, while there is limited information about the embryonic stages, in spite of their...     

Assessing the influence of cycloastragenol on telomere/telomerase system of Arabidopsis thaliana

Plant Cell, Tissue and Organ Culture (PCTOC) - Cycloastragenol (CAG) is a triterpenoid saponin compound that is synthesized by Astragalus species. CAG has many bioactivity, including telomerase...     

The secretome of mesenchymal stem cells and oxidative stress: challenges and opportunities in cell-free regenerative medicine

Molecular Biology Reports - Over the last decade, mesenchymal stem cells (MSCs) have been considered a suitable source for cell-based therapy, especially in regenerative medicine. First, the...     

A new set up for multi-analyte sensing: at-line bio-process monitoring

A multi-analyte sensing device is described, for simultaneous at-line monitoring of glucose, ethanol, pO?-value and cell density. It consists of a dual biosensor, a modified microscope and a fiber optical pO?-sensor that are integrated into a flow analysis (FA) system. The biosensor is based on a conventional thin layer flow-through cell equipped with a gold (Au) dual electrode (serial configuration). The biosensors with no cross-talking were produced by modifying the electrochemical transducers. Each Au surface was initially modified by self-assembled monolayer (SAM) of cysteamine. Alcohol oxidase (AOx) and pyranose oxidase (PyOx) were immobilized each onto a gold surface by means of PAMAM (polyamidoamine) dendrimer via glutaraldehyde cross-linking. The responses for glucose and ethanol were linear up to 0.5 mM. The operational stability of the biosensors was very promising, after 11 h continuous operation, only 6.0% of the initial activity was lost. The potential of the described biosensor was demonstrated by parallel determination of ethanol and glucose in yeast fermentation process. Simultaneously the cell density of the culture was monitored with an in situ microscope (ISM), which was integrated into the FA system. Both the used in situ microscope and the image processing algorithm used for the analysis of the acquired image data are described. Furthermore the pO?-value was monitored using a fiber optical sensor, which was embedded in a flow cell. The multi-sensor device allows the at-line monitoring of several process values without the need for further sampling or time consuming offline measurements.     

Amelogenesis Imperfecta in Two Families with Defined AMELX Deletions in ARHGAP6

Amelogenesis imperfecta (AI) is a group of inherited conditions featuring isolated enamel malformations. About 5% of AI cases show an X-linked pattern of inheritance, which are caused by mutations in AMELX. In humans there are two, non-allelic amelogenin genes: AMELX (Xp22.3) and AMELY (Yp11.2). About 90% of amelogenin expression is from AMELX, which is nested within intron 1 of the gene encoding Rho GTPase activating protein 6 (ARHGAP6). We recruited two AI families and determined that their disease-causing mutations were partial deletions in ARHGAP6 that completely deleted AMELX. Affected males in both families had a distinctive enamel phenotype resembling “snow-capped” teeth. The 96,240 bp deletion in family 1 was confined to intron 1 of ARHGAP6 (g.302534_398773del96240), but removed alternative ARHGAP6 promoters 1c and 1d. Analyses of developing teeth in mice showed that ARHGAP6 is not expressed from these promoters in ameloblasts. The 52,654 bp deletion in family 2 (g.363924_416577del52654insA) removed ARHGAP6 promoter 1d and exon 2, precluding normal expression of ARHGAP6. The male proband of family 2 had slightly thinner enamel with greater surface roughness, but exhibited the same pattern of enamel malformations characteristic of males in family 1, which themselves showed minor variations in their enamel phenotypes. We conclude that the enamel defects in both families were caused by amelogenin insufficiency, that deletion of AMELX results in males with a characteristic snow-capped enamel phenotype, and failed ARHGAP6 expression did not appreciably alter the severity of enamel defects when AMELX was absent.     

Synthesis and evaluation of antioxidant activity of new quinoline-2-carbaldehyde hydrazone derivatives: bioisosteric melatonin analogues

Overproduction of reactive oxygen species results in oxidative stress that can cause fatal damage to vital cell structures. It is known that the use of antioxidants could be beneficial in the prevention or delay of numerous diseases associated with oxidative stress. Melatonin (MLT) is known as a powerful free-radical scavenger and antioxidant. It was found that indole ring of MLT can be employed by bioisosteric replacement by other aromatic rings. Quinoline derivatives constitute an important class of compounds for new drug development. Owing to quinoline and hydrazones appealing physiological properties and are mostly found in numerous biologically active compounds a series of quinoline-2-carbaldehyde hydrazone derivatives were synthesized as bioisosteric analogues of MLT, characterized and in vitro antioxidant activity was investigated by evaluating their reducing effect against oxidation of a redox-sensitive fluorescent probe. Cytotoxicity potential of all compounds was investigated both by lactate dehydrogenase leakage assay and by MTT assay.