Protective effects of vitamin E against hypercholesterolemia-induced age-related diseases

Hypercholesterolemia is a major risk factor for age-related diseases such as atherosclerosis and Alzheimer’s disease (AD). Changes in human plasma cholesterol levels results from the interaction between multiple genetic and environmental factors. The accumulation of excess cholesterol in blood vessels leads to atherosclerosis. Many studies on this field show that differential expression of oxidative stress-related proteins, lipid metabolism-related enzymes, and receptors response to atherogenic diet. Additionally, excess brain cholesterol has been associated with increased formation and deposition of amyloid-β peptide from amyloid precursor protein which may contribute to the risk and pathogenesis of AD. To consider genetically, more than 50 genes have been reported to influence the risk of late-onset AD. Some of these genes might be also important in cholesterol metabolism and transport. Epidemiological studies have shown an association between high intake and high serum concentrations of antioxidant vitamins like vitamin E and lower rates of ischemic heart diseases. It has been known that vitamin E also inhibits smooth muscle cell proliferation by non-antioxidant mechanism. On the basis of the previous results, vitamin E has been accepted as an important protective factor against hypercholesterolemia-induced age-related diseases.     

Chromatin repair after oxidative stress: Role of PARP-mediated proteasome activation

Oxidative stress is an inevitable process in the nucleus, especially in antitumor chemotherapy, and adaptation by defense mechanisms seems to be one element in the development of long-term resistance to many chemotherapeutic drugs. In this study, a potential chromatin repair mechanism during oxidative stress was investigated in HT22 cells. The 20S proteasome has been shown to be largely responsible for the degradation of oxidatively modified histone proteins in the nucleus. Poly(ADP-ribosyl)ation reactions also play an important role in DNA repair as a consequence of oxidative damage and single-strand breaks. Such a reaction may occur also with the 20S proteasome—with a known increase in enzymatic activity—and also with histones—reducing their proteolytic susceptibility as shown for the first time here. After hydrogen peroxide treatment of HT22 cells, degradation of the model peptide substrate suc-LLVY-MCA and degradation of oxidized histones by nuclear proteasome increased. During the removal of protein carbonyls, single-strand breaks and 8-hydroxy-2′-deoxyguanosine, proteasome, and poly(ADP-ribose) polymerase-1 enzymes were shown to play tightly interacting roles. Our results following the repair of oxidative damage show the proteolytic activation of proteasome concerning poly(ADP-ribosyl)ation together with a decline in poly(ADP-ribosyl)ation of oxidized histones, leading to a selective recognition of oxidatively modified histones.     

Integration of Metabolic Modeling and Phenotypic Data in Evaluation and Improvement of Ethanol Production Using Respiration-Deficient Mutants of Saccharomyces cerevisiae

Flux balance analysis and phenotypic data were used to provide clues to the relationships between the activities of gene products and the phenotypes resulting from the deletion of genes involved in respiratory function in Saccharomyces cerevisiae. The effect of partial or complete respiratory deficiency on the ethanol production and growth characteristics of hap4Δ/hap4Δ, mig1Δ/mig1Δ, qdr3Δ/qdr3Δ, pdr3Δ/pdr3Δ, qcr7Δ/qcr7Δ, cyt1Δ/cyt1Δ, and rip1Δ/rip1Δ mutants grown in microaerated chemostats was investigated. The study provided additional evidence for the importance of the selection of a physiologically relevant objective function, and it may improve quantitative predictions of exchange fluxes, as well as qualitative estimations of changes in intracellular fluxes. Ethanol production was successfully predicted by flux balance analysis in the case of the qdr3Δ/qdr3Δ mutant, with maximization of ethanol production as the objective function, suggesting an additional role for Qdr3p in respiration. The absence of similar changes in estimated intracellular fluxes in the qcr7Δ/qcr7Δ mutant compared to the rip1Δ/rip1Δ and cyt1Δ/cyt1Δ mutants indicated that the effect of the deletion of this subunit of complex III was somehow compensated for. Analysis of predicted flux distributions indicated self-organization of intracellular fluxes to avoid NAD⁺/NADH imbalance in rip1Δ/rip1Δ and cyt1Δ/cyt1Δ mutants, but not the qcr7Δ/qcr7Δ mutant. The flux through the glycerol efflux channel, Fps1p, was estimated to be zero in all strains under the investigated conditions. This indicates that previous strategies for improving ethanol production, such as the overexpression of the glutamate synthase gene GLT1 in a GDH1 deletion background or deletion of the glycerol efflux channel gene FPS1 and overexpression of GLT1, are unnecessary in a respiration-deficient background.     

Temporary assisting suspension suture technique for successful microvascular anastomosis of extremely small and thin walled vessels for mice transplantation surgery

Dissection and microsurgical anastomosis in small and thin-walled vessels is challenging. Temporary assisting suspension suture technique was developed to overcome those difficulties in establishing successful composite tissue allotransplantation in mice. The operations were performed in 12- to 16-week-old Balb/c mice weighing 25 to 30 grams as both donor and recipient animals. Extended vascularized groin cutaneous flaps based on the superficial epigastric vessels were used. A total of 10 groin cutaneous flaps were transplanted. Three temporary assisting suspension sutures of 11-0 nylon were placed at the 12-, 4-, and 8-o'clock positions to donor and recipient artery and vein before the anastomosis. This technique allowed atraumatic dissection of delicate and thin vessels, prevented vessel wall collapse, and facilitated adequate exposure of the lumen during placement of the permanent microvascular sutures. Thus, the microvascular anastomosis was performed in an unusual manner. The temporary assisting suspension sutures were removed just before the permanent suture was tied down. The mean operation time was 1 hour and 45 minutes with an ischemia time of 1 hour. Ninety-percent success in immediate and late-term patency rates was achieved, which was confirmed by transplant survival. This technique was proven to be useful for microvascular anastomosis in thin-walled vessels and is recommended.     

Balamuthia mandrillaris, free-living ameba and opportunistic agent of encephalitis, is a potential host for Legionella pneumophila bacteria

Balamuthia mandrillaris is a free-living ameba and an opportunistic agent of granulomatous encephalitis in humans and other mammalian species. Other free-living amebas, such as Acanthamoeba and Hartmannella, can provide a niche for intracellular survival of bacteria, including the causative agent of Legionnaires' disease, Legionella pneumophila. Infection of amebas by L. pneumophila enhances the bacterial infectivity for mammalian cells and lung tissues. Likewise, the pathogenicity of amebas may be enhanced when they host bacteria. So far, the colonization of B. mandrillaris by bacteria has not been convincingly shown. In this study, we investigated whether this ameba could host L. pneumophila bacteria. Our experiments showed that L. pneumophila could initiate uptake by B. mandrillaris and could replicate within the ameba about 4 to 5 log cycles from 24 to 72 h after infection. On the other hand, a dotA mutant, known to be unable to propagate in Acanthamoeba castellanii, also did not replicate within B. mandrillaris. Approaching completion of the intracellular cycle, L. pneumophila wild-type bacteria were able to destroy their ameboid hosts. Observations by light microscopy paralleled our quantitative data and revealed the rounding, collapse, clumping, and complete destruction of the infected amebas. Electron microscopic studies unveiled the replication of the bacteria in a compartment surrounded by a structure resembling rough endoplasmic reticulum. The course of intracellular infection, the degree of bacterial multiplication, and the ultrastructural features of a L. pneumophila-infected B. mandrillaris ameba resembled those described for other amebas hosting Legionella bacteria. We hence speculate that B. mandrillaris might serve as a host for bacteria in its natural environment.     

Chemical Profile and Cytotoxicity Evaluation of Aerial Parts of Marrubium vulgare L. From Different Locations in Turkey

Marrubium vulgare L. (Lamiaceae) is used for respiratory and gastrointestinal system disorders in folk medicine. According to European Pharmacopoeia criteria, standardization of the plant is defined by its marrubiin content. In present study, phenolics, marrubiin and essential oil compositions of M. vulgare from different locations in Turkey were analyzed quantitatively by UPLC, GC and GC/MS. Besides, their cytotoxic potentials were evaluated. In the samples, forsythoside B (77–400 mg/100 g dw), arenarioside (forsythoside F) (0–241 mg/100 g dw), verbascoside (acteoside) (171–416 mg/100 g dw) and apigenin-7-O-glucoside (0–17 mg/100 g dw) were determined in different ranges. Marrubiin contents (0.58–1.46 %) of some samples were two times higher than European Pharmacopoeia standards (0.7 %). β-Caryophyllene (7.24–20.34 %), (Z)-β-farnesene (1.58–34.85 %), germacrene D (9.8–13.37 %), bicyclogermacrene (1.71–8.63 %) and β-bisabolene (0–16.68 %) were detected as major compounds in essential oils. The sample from the west of Aegean Region showed cytotoxicity against human neuroblastoma (SH-SY5Y) cell lines (IC₅₀: 59.80 μg/mL) although it has no effect on non-cancerous NIH-3T3cell lines. This is the first report on phenolic profiles of M. vulgare populations from Turkey. Their potential as marrubiin source for pharmaceutical industry should be considered.