Hepatitis C virus (HCV) is a highly pathogenic human virus associated with liver fibrosis, steatosis, and cancer. In infected cells HCV induces oxidative stress. Here, we show that HCV proteins core, ...E1, E2, NS4B, and NS5A activate antioxidant defense Nrf2/ARE pathway via several independent mechanisms. This was demonstrated by the analysis of transient co-expression in Huh7 cells of HCV proteins and luciferase reporters. Expression, controlled by the promoters of stress-response genes or their minimal Nrf2-responsive elements, was studied using luminescence assay, RT-qPCR and/or Western-blot analysis. All five proteins induced Nrf2 activation by protein kinase C in response to accumulation of reactive oxygen species (ROS). In addition, expression of core, E1, E2, NS4B, and NS5A proteins resulted in the activation of Nrf2 in a ROS-independent manner. The effect of core and NS5A was mediated through casein kinase 2 and phosphoinositide-3 kinase, whereas those of NS4B, E1, and E2, were not mediated by either PKC, CK2, PI3K, p38, or ERK. Altogether, on the earliest stage of expression HCV proteins induced a strong up-regulation of the antioxidant defense system. These events may underlie the harmful effects of HCV-induced oxidative stress during acute stage of hepatitis C.
Cancer and drug-resistant superinfections are common and serious problems afflicting millions worldwide. Photodynamic therapy (PDT) is a successful and clinically approved modality used for the ...management of many neoplastic and nonmalignant diseases. The combination of the light-activated molecules, so-called photosensitizers (PSs), with an appropriate carrier, is proved to enhance PDT efficacy both in vitro and in vivo. In this paper, we focus on the solvation of several potential chlorin PSs in the 1-octanol/phosphate saline buffer biphasic system, their interaction with non-ionic surfactant Tween 80 and photoinactivation of cancer cells. The chlorin conjugates containing
galactose and
-arginine fragments are found to have a much stronger affinity towards a lipid-like environment compared to ionic chlorins and form molecular complexes with Tween 80 micelles in water with two modes of binding. The charged macrocyclic PSs are located in the periphery of surfactant micelles near hydrophilic head groups, whereas the
-galactose and
-arginine conjugates are deeper incorporated into the micelle structure occupying positions around the first carbon atoms of the hydrophobic surfactant residue. Our results indicate that both PSs have a pronounced affinity toward the lipid-like environment, leading to their preferential binding to low-density lipoproteins. This and the conjugation of chlorin e
with the tumor-targeting molecules are found to enhance their accumulation in cancer cells and PDT efficacy.
Unsteady modeling of the thermal stress and dislocations in silicon ingots grown by seed-directional solidification has been done for three cooling regimes to study the effect of the model ...parameters. To track the history of dislocation multiplication, our computations continuously consider the growth process from the beginning of crystallization on the seed to the end of cooling of the grown crystal. The way that a cooling regime may affect the residual stress and dislocation distribution in the crystal is discussed. The computational results show good agreement with experimental data for both residual stress and dislocation density. Our results have confirmed that conjugated unsteady modeling is a promising way to investigate the effect of various growth conditions as well as the growth system design on the residual stress distribution, which is an important parameter of crystal quality.
There are two superoxide dismutases in the yeast Saccharomyces cerevisiae-cytoplasmic and mitochondrial enzymes. Inactivation of the cytoplasmic enzyme, Sod1p, renders the cells sensitive to a ...variety of stresses, while inactivation of the mitochondrial isoform, Sod2p, typically has a weaker effect. One exception is ethanol-induced stress. Here we studied the role of Sod2p in ethanol tolerance of yeast. First, we found that repression of SOD2 prevents ethanol-induced relocalization of yeast hydrogen peroxide-sensing transcription factor Yap1p, one of the key stress resistance proteins. In agreement with this, the levels of Trx2p and Gsh1p, proteins encoded by Yap1 target genes, were decreased in the absence of Sod2p. Analysis of the ethanol sensitivities of the cells lacking Sod2p, Yap1p, or both indicated that the two proteins act in the same pathway. Moreover, preconditioning with hydrogen peroxide restored the ethanol resistance of yeast cells with repressed SOD2 Interestingly, we found that mitochondrion-to-nucleus signaling by Rtg proteins antagonizes Yap1p activation. Together, our data suggest that hydrogen peroxide produced by Sod2p activates Yap1p and thus plays a signaling role in ethanol tolerance.
Baker's yeast harbors multiple systems that ensure tolerance to high concentrations of ethanol. Still, the role of mitochondria under severe ethanol stress in yeast is not completely clear. Our study revealed a signaling function of mitochondria which contributes significantly to the ethanol tolerance of yeast cells. We found that mitochondrial superoxide dismutase Sod2p and cytoplasmic hydrogen peroxide sensor Yap1p act together as a module of the mitochondrion-to-nucleus signaling pathway. We also report cross talk between this pathway and the conventional retrograde signaling cascade activated by dysfunctional mitochondria.
A series of novel 5'-norcarbocyclic derivatives of 5-alkoxymethyl or 5-alkyltriazolyl-methyl uracil were synthesized and the activity of the compounds evaluated against both Gram-positive and ...Gram-negative bacteria. The growth of
was completely inhibited by the most active compounds at a MIC
of 67 μg/mL (mc²155) and a MIC
of 6.7⁻67 μg/mL (VKPM Ac 1339). Several compounds also showed the ability to inhibit the growth of attenuated strains of
ATCC 25177 (MIC
28⁻61 μg/mL) and
ATCC 35737 (MIC
50⁻60 μg/mL), as well as two virulent strains of
; a laboratory strain H37Rv (MIC
20⁻50 μg/mL) and a clinical strain with multiple drug resistance MS-115 (MIC
20⁻50 μg/mL). Transmission electron microscopy (TEM) evaluation of
H37Rv bacterial cells treated with one of the compounds demonstrated destruction of the bacterial cell wall, suggesting that the mechanism of action for these compounds may be related to their interactions with bacteria cell walls.
Condensation of 5-aminoisoxazoles bearing substituents at position 3 with diethyl 2-oxosuccinate sodium salt in trifluoroacetic acid proceeded with the formation of diethyl (
Z
...)-2-(5-amino-3-methylisoxazol-4-yl)but-2-enedioates. Cyclization of the latter in the presence of sodium ethoxide in alcohol provided ethyl 6-hydroxyisoxazolo5,4-
b
pyridine-4-carboxylates. Ester hydrolysis gave the respective 6-hydroxyisoxazolo5,4-
b
pyridine-4-carboxylic acids.
Flax (Linum usitatissimum L.) is grown for fiber and seed production. Unfavorable environments, such as nutrient deficiency and non-optimal soil acidity, decrease the quantity and quality of yield. ...Cultivation of tolerant to stress varieties can significantly reduce the crop losses. Understanding the mechanisms of flax response to the stresses and identification of resistance gene candidates will help in breeding of improved cultivars. In the present work, the response of flax plants to increased pH level and zinc (Zn) deficiency was studied.
We performed high-throughput transcriptome sequencing of two flax cultivars with diverse tolerance to increased pH level and Zn deficiency: Norlin (tolerant) and Mogilevsky (sensitive). Sixteen cDNA libraries were created from flax plants grown under control conditions, increased pH level, Zn deficiency, and both stresses simultaneously, and about 35 million reads were obtained for each experiment type. Unfavorable pH resulted in significantly stronger gene expression alterations compared to Zn deficiency. Ion homeostasis, oxidoreductase activity, cell wall, and response to stress Gene Ontology terms were the most affected by unfavorable pH and Zn deficiency both in tolerant and sensitive flax cultivars. Upregulation of genes encoding metal transporters was identified under increased pH level, Zn deficiency, and both stresses simultaneously. Under Zn deficiency, only in tolerant cultivar Norlin, we revealed the induction of several photosynthesis-related genes and, in this way, this tolerant genotype could overcome unfavorable effects of reduced Zn content.
We identified genes with expression alterations in flax under non-optimal soil acidity and Zn deficiency based on high-throughput sequencing data. These genes are involved in diverse processes, including ion transport, cell wall biogenesis, and photosynthesis, and could play an important role in flax response to the studied stresses. Moreover, genes with distinct expression changes between examined tolerant and sensitive genotypes could determine the mechanisms of flax tolerance to non-optimal soil acidity and Zn deficiency.
Color vision sensitivity is crucial for fish adaptation during migration and reproduction. Prolactin and prolactin-like hormone are important regulators in both these processes. We hypothesized that ...prolactin influences the color vision sensitivity during freshwater migrations in fish. We studied the effects of prolactin and freshwater adaptation during the spawning period on the expression of opsin genes (
SWS1
,
SWS2
,
RH2
,
LWS
) in the retina of female and male three-spined sticklebacks
Gasterosteus aculeatus
L. Expression of the prolactin gene increased in the brain of females, but not males, while expression of the prolactin-like hormone decreased in the brain of both male and female sticklebacks during freshwater adaptation. Expression of the
SWS2
gene decreased in the retina of females and males during freshwater adaptation and after prolactin administration. Expression of the
SWS1
gene decreased in the retina of male sticklebacks after prolactin administration, but not during freshwater adaptation. Expression of the
RH2
and
LWS
genes did not depend on prolactin administration in male and female sticklebacks. We conclude that expression of some opsin genes in the retina of sticklebacks is regulated by prolactin and depends on sex and freshwater adaptation. This expands our knowledge of the adaptive effects of prolactin on fish during freshwater migrations.
A limited decrease in mitochondrial membrane potential can be beneficial for cells, especially under some pathological conditions, suggesting that mild uncouplers (protonophores) causing such an ...effect are promising candidates for therapeutic uses. The great majority of protonophores are weak acids capable of permeating across membranes in their neutral and anionic forms. In the present study, protonophorous activity of a series of derivatives of cationic rhodamine 19, including dodecylrhodamine (C12R1) and its conjugate with plastoquinone (SkQR1), was revealed using a variety of assays. Derivatives of rhodamine B, lacking dissociable protons, showed no protonophorous properties. In planar bilayer lipid membranes, separating two compartments differing in pH, diffusion potential of H+ ions was generated in the presence of C12R1 and SkQR1. These compounds induced pH equilibration in liposomes loaded with the pH probe pyranine. C12R1 and SkQR1 partially stimulated respiration of rat liver mitochondria in State 4 and decreased their membrane potential. Also, C12R1 partially stimulated respiration of yeast cells but, unlike the anionic protonophore FCCP, did not suppress their growth. Loss of function of mitochondrial DNA in yeast (grande-petite transformation) is known to cause a major decrease in the mitochondrial membrane potential. We found that petite yeast cells are relatively more sensitive to the anionic uncouplers than to C12R1 compared with grande cells. Together, our data suggest that rhodamine 19-based cationic protonophores are self-limiting; their uncoupling activity is maximal at high membrane potential, but the activity decreases membrane potentials, which causes partial efflux of the uncouplers from mitochondria and, hence, prevents further membrane potential decrease.
Progesterone and its synthetic analogues act on cells through different types of receptors, affecting proliferation and apoptosis. These compounds exert their effect through the nuclear receptors and ...the insufficiently studied membrane progesterone receptors (mPRs) belonging to the progestin and adiponectin Q receptor (PAQR) family. We have identified two selective ligands of mPRs that activate only this type of progesterone receptors – 19-hydroxypregn-4-en-20-one (LS-01) and 19-hydroxy-5β-pregn-3-en-20-one (LS-02). The goal of this work is to study the effect of these compounds on proliferation and death of human pancreatic adenocarcinoma cells BxPC3 and involvement of the two kinases (p38 MAPK and JNK) in signaling pathways activated by progestins through mPRs. It was shown that progesterone and the compound LS-01 significantly (
p
< 0.05) inhibited the BxPC3 cell viability, with JNK serving as a mediator. The identified targets of these two steroids are the genes of the proteins Ki67, cyclin D1, PCNA, and p21. Progesterone and the compound LS-01 significantly (
p
< 0.05) stimulate DNA fragmentation, enhancing the cell death. The p38 mitogen-activated protein kinase (MAPK) is a key mediator of this process. The BCL2A1 protein gene was identified as a target of both steroids. The compound LS-02 significantly (
p
< 0.05) alters membrane permeability and changes the exposure of phosphatidylserine on the outer membrane leaflet, also enhancing the cell death. This compound acts on these processes by activating both kinases, JNK and p38 MAPK. The compound LS-02 targets the genes encoding the proteins HRK, caspase 9, and DAPK.
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