Stability of diether C(25,25) liposomes from the hyperthermophilic archaeon Aeropyrum pernix K1

Temperature and pH effects were studied for stability, structural organization, fluidity and permeability of vesicles from a polar lipid methanol fraction isolated from the Aeropyrum pernix. We determined the permeability of C_25,25 liposomes using fluorescence intensity of released calcein. At pH 7.0 and 9.0, and from 85 °C to 98 °C, only 10% of entrapped calcein was released. After 10 h at 90 °C, calcein release reached 27%, independent of pH. Fluorescence anisotropy measurements of hydrophobic probe 1,6-diphenyl-1,3,5-hexatriene revealed gradual changes up to 60 °C. At higher temperatures, the anisotropy did not change significantly. Fluorescence alone did not provide detailed and direct structural information about these C_25,25 liposomes, so we used electron paramagnetic resonance spectroscopy (EPR) and differential scanning calorimetry (DSC). From EPR spectra, mean membrane fluidity determined according to maximal hyperfine splitting and empirical correlation times showed continuous increases with temperature. Computer simulation of EPR spectra showed heterogeneous membranes of these C_25,25 liposomes: at low temperatures, they showed three types of membrane regions characterized by different motional modes. Above 65 °C, the membrane becomes homogeneous with only one fluid-like region. DSC thermograms of C_25,25 liposomes reveal a very broad and endothermic transition in the temperature range from 0 °C to 40 °C.     

Purvalanol A is a strong apoptotic inducer via activating polyamine catabolic pathway in MCF-7 estrogen receptor positive breast cancer cells

Purvalanol A is a specific CDK inhibitor which triggers apoptosis by causing cell cycle arrest in cancer cells. Although it has strong apoptotic potential, the mechanistic action of Purvalanol A on significant cell signaling targets has not been clarified yet. Polyamines are crucial metabolic regulators affected by CDK inhibition because of their role in cell cycle progress as well. In addition, malignant cells possess impaired polyamine homeostasis with high level of intracellular polyamines. Especially induction of polyamine catabolic enzymes spermidine/spermine N1-acetyltransferase (SSAT), polyamine oxidase (PAO) and spermine oxidase (SMO) induced toxic by-products in correlation with the induction of apoptosis in cancer cells. In this study, we showed that Purvalanol A induced apoptosis in caspase- dependent manner in MCF-7 ER(+) cells, while MDA-MB-231 (ER?) cells were less sensitive against drug. In addition Bcl-2 is a critical target for Purvalanol A, since Bcl-2 overexpressed cells are more resistant to Purvalanol A-mediated apoptosis. Furthermore, exposure of MCF-7 cells to Purvalanol A triggered SSAT and PAO upregulation and the presence of PAO/SMO inhibitor, MDL 72,527 prevented Purvalanol A-induced apoptosis.     

CD103 is a marker for alloantigen-induced regulatory CD8+ T cells

The alphaEbeta7 integrin CD103 may direct lymphocytes to its ligand E-cadherin. CD103 is expressed on T cells in lung and gut and on allograft-infiltrating T cells. Moreover, recent studies have documented expression of CD103 on CD4+ regulatory T cells. Approximately 4% of circulating CD8+ T cells bear the CD103 molecule. In this study, we show that the absence or presence of CD103 was a stable trait when purified CD103- and CD103+ CD8+ T cell subsets were stimulated with a combination of CD3 and CD28 mAbs. In contrast, allostimulation induced CD103 expression on approximately 25% of purified CD103- CD8+ T cells. Expression of CD103 on alloreactive cells was found to be augmented by IL-4, IL-10, or TGF-beta and decreased by addition of IL-12 to MLCs. The alloantigen-induced CD103+ CD8+ T cell population appeared to be polyclonal and retained CD103 expression after restimulation. Markedly, in vitro-expanded CD103+ CD8+ T cells had low proliferative and cytotoxic capacity, yet produced considerable amounts of IL-10. Strikingly, they potently suppressed T cell proliferation in MLC via a cell-cell contact-dependent mechanism. Thus, human alloantigen-induced CD103+ CD8+ T cells possess functional features of regulatory T cells.     

Interaction between Oligomers of Stefin B and Amyloid-�� in Vitro and in Cells

To contribute to the question of the putative role of cystatins in Alzheimer disease and in neuroprotection in general, we studied the interaction between human stefin B (cystatin B) and amyloid-β-(1–40) peptide (Aβ). Using surface plasmon resonance and electrospray mass spectrometry we were able to show a direct interaction between the two proteins. As an interesting new fact, we show that stefin B binding to Aβ is oligomer specific. The dimers and tetramers of stefin B, which bind Aβ, are domain-swapped as judged from structural studies. Consistent with the binding results, the same oligomers of stefin B inhibit Aβ fibril formation. When expressed in cultured cells, stefin B co-localizes with Aβ intracellular inclusions. It also co-immunoprecipitates with the APP fragment containing the Aβ epitope. Thus, stefin B is another APP/Aβ-binding protein in vitro and likely in cells.     

Neuropeptide changes in the suprachiasmatic nucleus are associated with the development of hypertension

ABSTRACT

Human postmortem studies as well as experimental animal studies indicate profound changes in neuropeptide expression in the suprachiasmatic nucleus (SCN) in several pathological conditions including hypertension. In addition, animal experimental observations show that the SCN peptides, vasopressin (AVP) and vasoactive intestinal peptide (VIP) are essential for adequate rhythmicity. These data prompted us to investigate whether changes in these neuronal populations could be the cause or consequence of hypertension. Changes in blood pressure and levels of neuropeptide expression in the SCN were determined during development of hypertension in spontaneously hypertensive rats (SHR), in 2K1C reno-vascular induced hypertensive animals and their respective controls. During the pre-hypertensive stage (5 weeks of age), the VIP and AVP content was higher and the somatostatin (SOM) content was lower in the SHR SCN. At the onset of hypertension (12 weeks of age), when blood pressure levels had just reached about 140 mmHg, AVP and SOM content in the SCN was not different anymore in SHRs compared to control, but VIP was still higher. After 16 weeks, the AVP content was decreased, but SOM was increased and the overall level of VIP in the SCN was still higher in SHRs compared to controls. None of the aforementioned changes in the SCN was observed after induction of hypertension in the 2K1C model. However, while VIP was increased in the NTS projecting medial region of the SCN in SHR animals only after the establishment of hypertension, VIP was decreased in the same region in the 2K1C induced hypertensive rats. Consequently, the present findings confirm previous studies in human and rat indicating that changes in the SCN are strongly associated with the development of hypertension. In addition, the changes in peptide content in the 2K1C animals indicate that the SCN is also able to respond to increases in blood pressure.     

Molecular phylogeny of the subterranean genus Niphargus (Crustacea: Amphipoda) in the Middle East: a comparison with European Niphargids

The subterranean genus Niphargus is one of the most species‐rich genera among freshwater amphipods in the world, distributed in the Western Palearctic. Thus far, taxonomic and phylogenetic research has focused mainly on the European half of the genus range. In this study, 25 populations of Niphargus from Iran, Lebanon and the Crimean Peninsula were investigated. Bayesian inference based on 28S, H3 and COI gene sequences suggests that populations from the area belong to four different clades. Three species from Crimea and one species from Iran are nested at basal nodes, indicating their rather ancient origin. The rest of the species are younger and belong to two separate clades. One Crimean species is a sister‐species to east Romanian species. The second clade includes one species from Lebanon and all but one population from Iran. The origin of this clade corresponds to marine transgression between the Black Sea and Mediterranean approximately 12 Mya. This clade was further investigated taxonomically. Revision of qualitative morphological traits and unilocus species delimitation methods using COI suggest that this clade comprises 12–16 species, of which only three have been described so far. Multilocus coalescence delimitation methods (using fragments of COI, 28S, H3 and ITS) strongly supported 11 of these species. The remaining populations comprise at least two species complexes that require further and more detailed taxonomic research. © 2015 The Linnean Society of London     

Interleukin-1B (-511) gene polymorphism is associated with acute coronary syndrome in the Turkish population

Objectives: acute coronary syndrome (ACS) is defined as an inflammatory disease associated with development of atherosclerosis and instability. IL-1 is a candidate inflammatory cytokine that is thought to trigger ACS. The purpose of this study was to determine the relationship between IL-1 gene family polymorphisms (IL-1RN, IL-1B in positions -511 and +3953) and ACS in the Turkish population. Methods: a total of 381 people participated in the study, with 117 control subjects and 264 ACS patients. Of the 264 ACS patients, 112 were diagnosed with stable angina pectoris (SAP) and 152 were diagnosed with unstable angina pectoris (USAP). The polymerase chain reaction (PCR) was used to determine the genotype of IL-1RN. The genotypes of IL-1B (-511 and +3953) were determined by PCR, followed by restriction enzyme digestion of the PCR products. Results: there were no significant differences in both IL-1RN, IL-1B (-511 and +3953) genotype distributions and IL-1RN allele frequencies between ACS patients and the control subjects. In addition, no association was observed in the allele frequency of IL-1B (-511 and +3953) between ACS patients and controls (p = 0.113 and p = 0.859, respectively), or between SAP patients and controls (p = 0.575 and p = 0.359, respectively). However, IL-1B allele 1 (C) (-511) polymorphism in USAP patients was found to be significantly different from that of control subjects (p = 0.041, OR: 2.01; 95% CI: 1.985-3.933). A significant difference was also observed between USAP and SAP patients for IL-1B (+3953) allele 1 (C) polymorphism; (p = 0.043, OR: 1.522; 95% CI: 1.012-2.88). Conclusion: these results show that IL-1RN gene polymorphism has no association with ACS. However, the allele 1 (C) of IL-1B (-511) may be a risk factor for susceptibility to USAP in the Turkish population.