Carbonic anhydrase activators: Activation of the β-carbonic anhydrase Nce103 from the yeast Saccharomyces cerevisiae with amines and amino acids

The protein encoded by the Nce103 gene of Saccharomyces cerevisiae, a β-carbonic anhydrase (CA, EC 4.2.1.1) designated as scCA, was investigated for its activation with amines and amino acids. scCA was poorly activated by amino acids such as l-/d-His, Phe, DOPA, Trp (K_As of 82–90 μM) and more effectively activated by amines such as histamine, dopamine, serotonin, pyridyl-alkylamines, aminoethyl-piperazine/morpholine (K_As of 10.2–21.3 μM). The best activator was l-adrenaline, with an activation constant of 0.95 μM. This study may help to better understand the catalytic/activation mechanisms of the β-CAs and eventually to design modulators of CA activity for similar enzymes present in pathogenic fungi, such as Candida albicans and Cryptococcus neoformans.     

Effects of chromium VI stress on photosynthesis,chlorophyll integrity,cell viability,and proline accumulation in lichen <Emphasis Type="Italic">Ramalina farinacea</Emphasis>

In order to contribute to understanding of the response to metal stress, Ramalina farinacea (L.) Ach. was treated with different concentrations of chromium (VI) (5, 15, and 30 mM of K₂CrO₄) for 1, 3, and 24 h, and alterations in the photosystem II photosynthetic quantum yield, pigment content, integrity of chlorophyll, cell viability, and proline accumulation were investigated. Significant alterations of the photosynthetic quantum yield (F _v/F _m) ratio were observed in response to the increase in chromium concentration. The F _v/F _m ratio decreased in R. farinacea following 24-h treatment with 30 mM Cr⁶⁺ solution. In present study, in both control and other plant groups treated with 5 mM Cr⁶⁺, the Chl a/b ratio was approximately within the range of 2.0–3.5. However, this ratio significantly decreased for the samples treated with 15 (exposure period of 24 h) and 30 mM; (exposure periods of 3 and 24 h) Cr⁶⁺. We also showed that cell viability of samples treated with 15 and 30 mM Cr⁶⁺ significantly decreased. Accumulation of metal resulted in proline accumulation in R. farinacea thalli; however, when photodestructive effects on photosystem II occurred, proline intracellular concentration declined. On the basis of these results, we suggest that proline accumulation might not be the stress marker during heavy metal stress.     

Influence of subacute treatment of some plant growth regulators on serum marker enzymes and erythrocyte and tissue antioxidant defense and lipid peroxidation in rats

This study aims to investigate the effects of the plant growth regulators (PGRs) (2,3,5-triiodobenzoic acid (TIBA), Naphthaleneacetic acid (NAA), and 2,4-dichlorofenoxyacetic acid (2,4-D)) on serum marker enzymes (aspartate aminotransferase (AST), alanin aminotransferase (ALT), creatine phosphokinase (CPK), and lactate dehydrogenase (LDH)), antioxidant defense systems (reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST), and catalase (CAT)), and lipid peroxidation content (malondialdehyde = MDA) in various tissues of rats. 50 and 100 ppm of PGRs as drinking water were administered orally to rats (Sprague-Dawley albino) ad libitum for 25 days continuously. The PGRs treatment caused different effects on the serum marker enzymes, antioxidant defense systems, and the MDA content in experimented rats compared to controls. Results showed that TIBA caused a significant decrease in serum AST activity with both the dosage whereas serum CPK was significantly increased with 100 ppm dosage of TIBA. Meanwhile, serum AST, CPK, and LDH activities were significantly increased with both dosage of NAA and 2,4-D. The lipid peroxidation end-product MDA significantly increased in the all tissues treated with both dosages of PGRs without any change in the brain and erythrocyte of rats treated with both the dosages of 2,4-D. The GSH depletion in the kidney and brain tissues of rats treated with both dosages of PGRs was found to be significant. Furthermore, the GSH depletion in the erythrocyte of rats treated with both dosages of PGRs except 50 ppm dosage of 2,4-D was significant too. Also, the GSH level in the liver was significantly depleted with 50 ppm of 2,4-D and NAA, whereas the GSH depletion in the same tissue did not significantly change with the treatment. The activity of antioxidant enzymes was also seriously affected by PGRs; SOD significantly decreased in the liver, heart, kidney, and brain of rats treated with both dosages of NAA, whereas the SOD activity in the erythrocytes, liver, and heart was either significantly decreased or not changed with two doses of 2,4-D and TIBA. Although the CAT activity significantly increased in the erythrocyte and brain of rats treated with both doses of PGRs, it was not changed in the liver, heart, and kidney. Meanwhile, the ancillary enzyme GR activity significantly increased in the brain, heart, and liver but decreased in the erythrocyte and kidney of rats treated with both doses of PGRs. The drug-metabolizing enzyme GST activity significantly increased in the heart and kidney but decreased in the brain and erythrocytes of rats treated with both dosages of PGRs. As a conclusion, the results indicate that PGRs might affect antioxidant potential enzymes, the activity of hepatic damage enzymes, and lipid peroxidation dose independently. Also, the rats resisted to oxidative stress via antioxidant mechanism but the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat's tissues. These data, along with the determined changes, suggest that PGRs produced substantial systemic organ toxicity in the erythrocyte, liver, brain, heart, and kidney during the period of a 25-day subacute exposure.     

House dust mite fauna in western Anatolia, Turkey

House dust mites play an important role in the pathogenesis of allergic diseases. Many factors may influence mite growth. The presence of mites is related to mean temperature and humidity as well as altitude. The aim of this study was to analyze the mite fauna in 5 regions of western Anatolia, Turkey, that have similar climatic properties with low mean temperature and humidity, but differ in altitude. During the period October-November 2004, house dust was collected from 290 homes in 5 different cities. House dust mites were isolated in 67 (23.1%) of 290 samples. The family Pyroglyphidae (Astigmata) was present in all positive samples. This study suggests that the selected western Anatolian regions that share similar environmental conditions host similar dust mite populations.     

Major QTL confer race-nonspecific resistance in the co-evolved Cronartium quercuum f. sp. fusiforme–Pinus taeda pathosystem

Fusiform rust disease, caused by the endemic fungus Cronartium quercuum f. sp. fusiforme, is the most damaging disease affecting economically important pine species in the southeast United States. Unlike the major epidemics of agricultural crops, the co-evolved pine-rust pathosystem is characterized by steady-state dynamics and high levels of genetic diversity within environments. This poses a unique challenge and opportunity for the deployment of large-effect resistance genes. We used trait dissection to study the genetic architecture of disease resistance in two P. taeda parents that showed high resistance across multiple environments. Two mapping populations (full-sib families), each with ~1000 progeny, were challenged with a complex inoculum consisting of 150 pathogen isolates. High-density linkage mapping revealed three major-effect QTL distributed on two linkage groups. All three QTL were validated using a population of 2057 cloned pine genotypes in a 6-year-old multi-environmental field trial. As a complement to the QTL mapping approach, bulked segregant RNAseq analysis revealed a small number of candidate nucleotide binding leucine-rich repeat genes harboring SNP associated with disease resistance. The results of this study show that in P. taeda, a small number of major QTL can provide effective resistance against genetically diverse mixtures of an endemic pathogen. These QTL vary in their impact on disease liability and exhibit additivity in combination.Subject terms: Genetic linkage study, Plant genetics     

The Effect of Low Dose Zinc Supplementation to Serum Estrogen and Progesterone Levels in Post-menopausal Women

The objective of the present study is to investigate how low-dose zinc supplementation for 2 weeks in the post-menopausal period influences levels of estrogen and progesterone in the serum. The study registered 32 natural menopause patients, who were allocated to four groups with equal number of patients. Group 1, control group, which was not subjected to any procedure. Group 2, the group that was supplemented with 15 mg/day zinc sulfate for 2 weeks. Group 3, the group that was given hormone replacement therapy (0.625 mg estrogen?+?5 mg medroxyprogesterone acetate/day) for 2 weeks. Group 4, the group that received hormone replacement therapy (0.625 mg estrogen?+?5 mg medroxyprogesterone acetate/day) and zinc sulfate (15 mg/day) for 2 weeks. Blood samples were collected twice from each subject, once at the beginning of the study, and once at the end of the 4-week procedure to determine estrogen (E2) and progesterone levels. Variance analysis was employed in the statistical evaluation of data. Level of significance was set at p?<?0.05. No significant difference was found between the estrogen and progesterone levels of groups 1 and 2. Groups 3 and 4 had higher estrogen and progesterone levels than groups 1 and 2 (p?<?0.05). Estrogen and progesterone levels in groups 3 and 4 were not different. Results of the study show that low-dose zinc supplementation to post-menopausal women for 2 weeks does not have a significant effect on the concerned parameters.     

Traditional Tar Production from <Emphasis Type="Italic">Cedrus libani</Emphasis> A. Rich on the Taurus Mountains in Southern Turkey

Traditional Tar Production from Cedrus libani A. Rich on the Taurus Mountains in Southern Turkey. Cedrus libani A. Rich is a magnificent and sacred tree species native to the eastern Mediterranean region. Today, traditional people in southern Turkey produce wood extract, called katran, from C. libani, and use it to protect wooden structures against insects and fungi, to fight parasites and bacteria, and to heal wounds and cure various diseases in humans and domestic animals, both internally and externally. Here we illustrate traditional methods of producing katran, its use by local people, and its chemical composition.     

Chimeric HIV-1 Envelope Glycoproteins with Potent Intrinsic Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) Activity*

HIV-1 acquisition can be prevented by broadly neutralizing antibodies (BrNAbs) that target the envelope glycoprotein complex (Env). An ideal vaccine should therefore be able to induce BrNAbs that can provide immunity over a prolonged period of time, but the low intrinsic immunogenicity of HIV-1 Env makes the elicitation of such BrNAbs challenging. Co-stimulatory molecules can increase the immunogenicity of Env and we have engineered a soluble chimeric Env trimer with an embedded granulocyte-macrophage colony-stimulating factor (GM-CSF) domain. This chimeric molecule induced enhanced B and helper T cell responses in mice compared to Env without GM-CSF. We studied whether we could optimize the activity of the embedded GM-CSF as well as the antigenic structure of the Env component of the chimeric molecule. We assessed the effect of truncating GM-CSF, removing glycosylation-sites in GM-CSF, and adjusting the linker length between GM-CSF and Env. One of our designed Env_GM-CSF chimeras improved GM-CSF-dependent cell proliferation by 6-fold, reaching the same activity as soluble recombinant GM-CSF. In addition, we incorporated GM-CSF into a cleavable Env trimer and found that insertion of GM-CSF did not compromise Env cleavage, while Env cleavage did not compromise GM-CSF activity. Importantly, these optimized Env_GM-CSF proteins were able to differentiate human monocytes into cells with a macrophage-like phenotype. Chimeric Env_GM-CSF should be useful for improving humoral immunity against HIV-1 and these studies should inform the design of other chimeric proteins.     

Amiodarone Inhibits Apamin-Sensitive Potassium Currents

Background

Apamin sensitive potassium current (I _KAS), carried by the type 2 small conductance Ca²⁺-activated potassium (SK2) channels, plays an important role in post-shock action potential duration (APD) shortening and recurrent spontaneous ventricular fibrillation (VF) in failing ventricles.

Objective

To test the hypothesis that amiodarone inhibits I _KAS in human embryonic kidney 293 (HEK-293) cells.

Methods

We used the patch-clamp technique to study I _KAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration.

Results

Amiodarone inhibited I_KAS in a dose-dependent manner (IC₅₀, 2.67±0.25 µM with 1 µM intrapipette Ca²⁺). Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6±3.1% of I_KAS induced with 1 µM intrapipette Ca²⁺ (n = 3). I_KAS inhibition by amiodarone was not voltage-dependent, but was Ca²⁺-dependent: 30 µM amiodarone inhibited 81.5±1.9% of I _KAS induced with 1 µM Ca²⁺ (n = 4), and 16.4±4.9% with 250 nM Ca²⁺ (n = 5). Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca²⁺ dependent inhibition of I _KAS.

Conclusion

Both amiodarone and desethylamiodarone inhibit I _KAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca²⁺ concentration. SK2 current inhibition may in part underlie amiodarone''s effects in preventing electrical storm in failing ventricles.