Dendroaspis natriuretic peptide protects the post-ischemic myocardial injury

The present study used isolated rat hearts to investigate whether (1) Dendroaspis natriuretic peptide (DNP) is protective against post-ischemic myocardial dysfunction, and (2) whether the cardioprotective effects of DNP is related to alteration of Bcl-2 family protein levels. The excised hearts of Sprague-Dawley rats were perfused on a Langendorff apparatus with Krebs-Henseleit solution with a gas mixture of 95% O2 and 5% CO2. Left ventricular end-diastolic pressure (LVEDP, mmHg), left ventricular developed pressure (LVDP, mmHg) and coronary flow (CF, ml/min) were continuously monitored. In the presence of 50 nM DNP, all hearts were perfused for a total of 100 min consisting of a 20 min pre-ischemic period followed by a 30 min global ischemia and 50 min reperfusion. Lactate dehydrogenase (LDH) activity in the effluent was measured during reperfusion. Treatment with DNP alone improved the pre-ischemic LVEDP and post-ischemic LVEDP significantly comparing with the untreated control hearts during reperfusion. However, DNP did not affect the LVDP, heart rate (HR, beats/min), and CF. Bcl-2, an anti-apoptotic protein expressed in ischemic myocardium of DNP+ischemia/reperfusion (I/R) group, was higher than that in I/R alone group. Bax, a pro-apoptotic protein expressed in ischemic myocardium of DNP+I/R group, has no significant difference compared with I/R alone group. These results suggest that the protective effects of DNP against I/R injury would be mediated, at least in part, through the increased ratio of Bcl-2 to Bax protein after ischemia-reperfusion.     

Effects of Fluridone and Norflurazon on Conditioning and Germination of Striga asiatica Seeds

Inhibitors of carotenoid biosynthesis are known to prevent abscisic acid (ABA) biosynthesis and to affect germination and dormancy of seeds in many plants. In this study, the effects of three carotenoid biosynthesis inhibitors, fluridone, norflurazon and diflufenican, on the conditioning and germination of Striga asiatica seeds were examined. Fluridone and norflurazon shortened the conditioning period required before S. asiatica seeds would germinate after exposure to the germination stimulant strigol, and prevented the inhibitory effects of both light and supraoptimal temperature (40 °C) on seed germination. In addition, treatment with fluridone or norflurazon after conditioning in water induced seed germination in a manner similar to the effect of natural germination stimulants. Moreover, the seedlings developing after conditioned with fluridone formed haustorium-like structures without the involvement of haustorium inducing factors. In contrast, diflufenican had no effect on the conditioning and germination of S. asiatica seeds. These results indicate that fluridone and norflurazon have various effects on the germination of S. asiatica seeds and might be available for control of root parasites.     

The peptidylglycine-α-amidating monooxygenase (<Emphasis Type="Italic">PAM</Emphasis>) gene rs13175330 A&gt;G polymorphism is associated with hypertension in a Korean population

Background

Peptidylglycine-α-amidating monooxygenase (PAM) may play a role in the secretion of atrial natriuretic peptide (ANP), which is a hormone involved in the maintenance of blood pressure (BP). The objective of the present study was to determine whether PAM is a novel candidate gene for hypertension (HTN).

Results

A total of 2153 Korean participants with normotension and HTN were included. Genotype data were obtained using the Korean Chip. The rs13175330 polymorphism of the PAM gene was selected from the ten single nucleotide polymorphisms (SNPs) most strongly associated with BP. The presence of the G allele of the PAM rs13175330 A>G SNP was associated with a higher risk of HTN after adjustments for age, sex, BMI, smoking, and drinking [OR 1.607 (95% CI 1.220–2.116), p?=?0.001]. The rs13175330 G allele carriers in the HTN group treated without antihypertensive therapy (HTN w/o therapy) had significantly higher systolic and diastolic BP than the AA carriers, whereas the G allele carriers in the HTN group treated with antihypertensive therapy (HTN w/ therapy) showed significantly higher diastolic BP. Furthermore, rs13175330 G allele carriers in the HTN w/o therapy group had significantly increased levels of insulin, insulin resistance, and oxidized low-density lipoprotein (LDL) and significantly decreased LDL-cholesterol levels and LDL particle sizes compared to the AA carriers.

Conclusion

These results suggest that the PAM rs13175330 A>G SNP is a novel candidate gene for HTN in the Korean population. Additionally, the PAM rs13175330 G allele might be associated with insulin resistance and LDL atherogenicity in patients with HTN.

     

Replication and pathogenesis of the pandemic (H1N1) 2009 influenza virus in mammalian models

This study aimed to characterize the replication and pathogenic properties of a Korean pandemic (H1N1) 2009 influenza virus isolate in ferrets and mice. Ferrets infected with A/Korea/01/2009 (H1N1) virus showed mild clinical signs. The virus replicated well in lungs and slightly in brains with no replication in any other organs. Severe bronchopneumonia and thickening of alveolar walls were detected in the lungs. Viral antigens were detected in the bronchiolar epithelial cells, in peribronchial glands with severe peribronchitis and in cells present in the alveoli. A/Korea/01/2009 (H1N1) virus-infected mice showed weight loss and pathological lung lesions including perivascular cuffing, interstitial pneumonia and alveolitis. The virus replicated highly in the lungs and slightly in the nasal tissues. Viral antigens were detected in bronchiolar epithelial cells, pneumocytes and interstitial macrophages. However, seasonal H1N1 influenza virus did not replicate in the lungs of ferrets, and viral antigens were not detected. Thus, this Korean pandemic (H1N1) 2009 isolate infected the lungs of ferrets and mice successfully and caused more pathological lesions than did the seasonal influenza virus.     

CDK2 differentially controls normal cell senescence and cancer cell proliferation upon exposure to reactive oxygen species

The linker of nucleus and cytoskeleton (LINC) complex, including nesprin-1, has been suggested to be crucial for many biological processes. Previous studies have shown that mutations in nesprin-1 cause abnormal cellular functions and diseases, possibly because of insufficient force transmission to the nucleus through actin filaments (F-actin) bound to nesprin-1. However, little is known regarding the mechanical interaction between the nucleus and F-actin through nesprin-1. In this study, we examined nuclear deformation behavior in nesprin-1 knocked-down endothelial cells (ECs) subjected to uniaxial stretching by evaluating nuclear strain from lateral cross-sectional images. The widths of nuclei in nesprin-1 knocked-down ECs were smaller than those in wild-type cells. In addition, nuclear strain in nesprin-1 knocked-down cells, which is considered to be compressed by the actin cortical layer, increased compared with that in wild-type cells under stretching condition. These results indicate that nesprin-1 knockdown releases the nucleus from the tension of F-actin bound to the nucleus, thereby increasing allowance for deformation before stretching, and that F-actin bound to the nucleus through nesprin-1 causes sustainable force transmission to the nucleus.     

Biocatalytic desulfurization of diesel oil in an air-lift reactor with immobilized Gordonia nitida CYKS1 cells

A new type of air-lift reactor with immobilized Gordonia nitida CYKS1 cells on a fibrous support was designed and used for the biocatalytic desulfurization (BDS) of diesel oil. Its performance was evaluated at different phase ratios of the oil to the aqueous medium (or oil phase fractions) and different sucrose concentrations. When the reaction mixture contained 10% diesel oil (v/v), 61-67% of sulfur was removed as the sulfur content decreased from 202-250 to 76-90 mg L(-1) in 72 h. The sulfur content did not decrease any further because the remaining sulfur compounds were recalcitrant to BDS. During the desulfurization, the strain CYKS1 consumed hydrocarbons in the diesel oil, mainly n-alkanes with 10-26 carbons, as carbon source even though an easily available carbon source, sucrose, was supplied.     

Effects of synthetic and naturally occurring flavonoids on metabolic activation of benzo[a]pyrene in hamster embryo cell cultures.

Biochanin A, an isoflavone, has previously been shown to inhibit the metabolic activation of the carcinogen benzo[a]pyrene (B[a]P) to metabolites that bind to DNA in hamster embryo cells and are mutagenic in Chinese hamster V79 cells. To determine the structural features required for this activity and to attempt to find more effective inhibitors, a series of synthetic and naturally occurring flavonids were tested for their ability to modulate B[a]P metabolism in hamster embryo cell cultures. The observed structure-activity relationships indicate that the structural features of flavonoids important for effective inhibition of B[a]P metabolism in hamster embryo cells are the presence of two hydroxyl, two methoxyl, or methyl and hydroxyl substituents at the 5- and 7-positions and a 2,3-double bond. Flavones are slightly better inhibitors of B[a]P metabolism than the corresponding isoflavones. A substituent at the 4'-position is not essential for inhibition of B bdP metabolism. The presence of a hydroxyl group at position 3 slightly enhances activity. Apigenin, acacetin and kaempferide are effective inhibitors of B[a]P-induced mutagenesis in a hamster embryo cell-mediated V79 cell mutation assay. However, apigenin is cytotoxic at the inhibitory dose, whereas acacetin and kaempferide are not. These results suggest that acacetin and kaempferide are promising candidates for in vivo testing as potential chemopreventive agents.     

GSH-dependent peroxidase activity of the rice (Oryza sativa) glutaredoxin,a thioltransferase

Glutaredoxin (Grx) is a 12-kDa thioltransferase that reduces disulfide bonds of other proteins and maintains the redox potential of cells. In addition to its oxidoreductase activity, we report here that a rice Grx (OsGrx) can also function as a GSH-dependent peroxidase. Because of this antioxidant activity, OsGrx protects glutamine synthetase from oxidative damage. Individually replacing the conserved Cys residues in OsGrx with Ser shows that Cys(23), but not Cys(26), is essential for the thioltransferase and GSH-dependent peroxidase activities. Kinetic characterization of OsGrx reveals that the maximal catalytic efficiency (V(max)/K(m)) is obtained with cumene hydroperoxide rather than H(2)O(2) or t-butyl hydroperoxide.     

Partial purification and characterization of an extracellular protease from<Emphasis Type="Italic">Xenorhabdus nematophilus</Emphasis>, a symbiotic bacterium isolated from an entomopathogenic nematode,<Emphasis Type="Italic">Steinernema glaseri</Emphasis>

Entomopathogenic nematodes are used for insect control. Herein, an extracellular protease was partially purified from a culture supernatant ofXenorhabdus nematophilus, a symbiotic bacterium of an entomopathogenic nematode,Steinernema glaseri, using precipitation with 80% v/v isopropyl alcohol followed by gel permeation chromatography with a packed Sephacryl S-300 HR media. The partially purified protease exhibited maximal activity at pH 7 in the presence of 1 mM CaCl₂. The protease was identified as a metallo-protease based on the inhibition of its activity by the metal chelating agent, EDTA.     

Tissue-specific down-regulation of RIPK 2 in Mycobacterium leprae-infected nu/nu mice

RIPK 2 is adapter molecule in the signal pathway involved in Toll-like receptors. However, there has been no reported association between receptor-interacting serine/threonine kinase 2 (RIPK 2) expression and the infectious diseases involving mycobacterial infection. This study found that its expression was down-regulated in the footpads and skin but was up-regulated in the liver of Mycobacterium leprae-infected nu/nu mice compared with those of the M. leprae non-infected nu/nu mice. It was observed that the interlukin-12p40 and interferon-gamma genes involved in the susceptibility of M. leprae were down-regulated in the skin but were up-regulated in the liver. Overall, this suggests that regulation of RIPK 2 expression is tissue-specifically associated with M. leprae infection.