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1

Gymnemic Acids Inhibit Hyphal Growth and Virulence in Candida albicans  

E-print Network

Gymnemic Acids Inhibit Hyphal Growth and Virulence in Candida albicans Govindsamy Vediyappan1 Candida albicans is an opportunistic and polymorphic fungal pathogen that causes mucosal, disseminated'Enfert C (2013) Gymnemic Acids Inhibit Hyphal Growth and Virulence in Candida albicans. PLoS ONE 8(9): e

Boyer, Edmond

2

Calcite crystal growth rate inhibition by polycarboxylic acids  

USGS Publications Warehouse

Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

Reddy, M. M.; Hoch, A. R.

2001-01-01

3

(Aminooxy)acetic acid inhibits petunia growth and gibberellin- and cytokinin-stimulated growth in bioassays  

Microsoft Academic Search

(Aminooxy)acetic acid (AOA) was applied to greenhouse-grown petunias and was used in bioassays for three plant growth hormones\\u000a so that its growth regulator properties could be studied. In greenhouse studies foliar sprays of 4.8–12 mm AOA inhibited vegetative growth of petunia seedlings (Petunia xhybrida Vilm. ‘White Flash’). When gibberellin A 3 (GA3) was applied to shoot tips previously treated with

Philip E. Hammer; David S. Koranski; Richard J. Gladont

1995-01-01

4

Liver acid sphingomyelinase inhibits growth of metastatic colon cancer  

PubMed Central

Acid sphingomyelinase (ASM) regulates the homeostasis of sphingolipids, including ceramides and sphingosine-1-phosphate (S1P). These sphingolipids regulate carcinogenesis and proliferation, survival, and apoptosis of cancer cells. However, the role of ASM in host defense against liver metastasis remains unclear. In this study, the involvement of ASM in liver metastasis of colon cancer was examined using Asm–/– and Asm+/+ mice that were inoculated with SL4 colon cancer cells to produce metastatic liver tumors. Asm–/– mice demonstrated enhanced tumor growth and reduced macrophage accumulation in the tumor, accompanied by decreased numbers of hepatic myofibroblasts (hMFs), which express tissue inhibitor of metalloproteinase 1 (TIMP1), around the tumor margin. Tumor growth was increased by macrophage depletion or by Timp1 deficiency, but was decreased by hepatocyte-specific ASM overexpression, which was associated with increased S1P production. S1P stimulated macrophage migration and TIMP1 expression in hMFs in vitro. These findings indicate that ASM in the liver inhibits tumor growth through cytotoxic macrophage accumulation and TIMP1 production by hMFs in response to S1P. Targeting ASM may represent a new therapeutic strategy for treating liver metastasis of colon cancer. PMID:23298833

Osawa, Yosuke; Suetsugu, Atsushi; Matsushima-Nishiwaki, Rie; Yasuda, Ichiro; Saibara, Toshiji; Moriwaki, Hisataka; Seishima, Mitsuru; Kozawa, Osamu

2013-01-01

5

Salicylic acid antagonizes abscisic acid inhibition of shoot growth and cell cycle progression in rice  

PubMed Central

We analysed effects of abscisic acid (ABA, a negative regulatory hormone), alone and in combination with positive or neutral hormones, including salicylic acid (SA), on rice growth and expression of cell cycle-related genes. ABA significantly inhibited shoot growth and induced expression of OsKRP4, OsKRP5, and OsKRP6. A yeast two-hybrid assay showed that OsKRP4, OsKRP5, and OsKRP6 interacted with OsCDKA;1 and/or OsCDKA;2. When SA was simultaneously supplied with ABA, the antagonistic effect of SA completely blocked ABA inhibition. SA also blocked ABA inhibition of DNA replication and thymidine incorporation in the shoot apical meristem. These results suggest that ABA arrests cell cycle progression by inducing expression of OsKRP4, OsKRP5, and OsKRP6, which inhibit the G1/S transition, and that SA antagonizes ABA by blocking expression of OsKRP genes. PMID:24686568

Meguro, Ayano; Sato, Yutaka

2014-01-01

6

Oleic acid inhibits stearic acid-induced inhibition of cell growth and pro-inflammatory responses in human aortic endothelial cells  

PubMed Central

Saturated fatty acids (SFAs), significant components of both enteral/parenteral nutritional formulations (including diet), are linked to cardiovascular disease complications, such as atherosclerosis. We investigated whether oleic acid (C18:1n-9) reduces the growth inhibitory and pro-inflammatory effects of the stearic acid (C18:0) in human aortic endothelial cells (HAEC). Stearic acid induced growth inhibition at concentrations less than 50 ?M, whereas higher concentrations invoked cytotoxicity. Stearic acid-induced growth inhibition and cytotoxic effects were eradicated upon cosupplementation with oleic acid (25 ?M). Oleic acid (as low as 5 ?M) also inhibited the stearic acid-induced increase in intercellular adhesion molecule-1 (ICAM-1) expression. Stearic acid-induced phosphorylation of nuclear factor-kappa B (NF-?B), a transcriptional regulator of ICAM-1, was also reduced by oleic acid. HAECs supplemented with either stearic or oleic acid resulted in cellular incorporation of C18:0 and C18:1n-9, respectively. Stearic acid primarily incorporated into phospholipids without increasing the total fatty acid content in HAECs. In contrast, oleic acid, with or without stearic acid, incorporated into both phospholipids and triglycerides, with a significant increase in total fatty acid amounts in triglycerides. Our data suggest that oleic acid has the ability to reduce the inflammatory effects of long-chain SFAs in HAECs through reducing cellular stearic acid incorporation and NF-?B activation. PMID:20852092

Harvey, Kevin A.; Walker, Candace L.; Xu, Zhidong; Whitley, Phillip; Pavlina, Thomas M.; Hise, Mary; Zaloga, Gary P.; Siddiqui, Rafat A.

2010-01-01

7

Auxin-Induced Ethylene Triggers Abscisic Acid Biosynthesis and Growth Inhibition1  

PubMed Central

The growth-inhibiting effects of indole-3-acetic acid (IAA) at high concentration and the synthetic auxins 7-chloro-3-methyl-8-quinolinecarboxylic acid (quinmerac), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 4-amino-3,6,6-trichloropicolinic acid (picloram), and naphthalene acetic acid, were investigated in cleavers (Galium aparine). When plants were root treated with 0.5 mm IAA, shoot epinasty and inhibition of root and shoot growth developed during 24 h. Concomitantly, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity, and ACC and ethylene production were transiently stimulated in the shoot tissue within 2 h, followed by increases in immunoreactive (+)-abscisic acid (ABA) and its precursor xanthoxal (xanthoxin) after 5 h. After 24 h of treatment, levels of xanthoxal and ABA were elevated up to 2- and 24-fold, relative to control, respectively. In plants treated with IAA, 7-chloro-3-methyl-8-quinolinecarboxylic acid, naphthalene acetic acid, 2-methoxy-3,6-dichlorobenzoic acid, and 4-amino-3,6,6-trichloropicolinic acid, levels of ethylene, ACC, and ABA increased in close correlation with inhibition of shoot growth. Aminoethoxyvinyl-glycine and cobalt ions, which inhibit ethylene synthesis, decreased ABA accumulation and growth inhibition, whereas the ethylene-releasing ethephon promoted ABA levels and growth inhibition. In accordance, tomato mutants defective in ethylene perception (never ripe) did not produce the xanthoxal and ABA increases and growth inhibition induced by auxins in wild-type plants. This suggests that auxin-stimulated ethylene triggers ABA accumulation and the consequent growth inhibition. Reduced catabolism most probably did not contribute to ABA increase, as indicated by immunoanalyses of ABA degradation and conjugation products in shoot tissue and by pulse experiments with [3H]-ABA in cell suspensions of G. aparine. In contrast, studies using inhibitors of ABA biosynthesis (fluridone, naproxen, and tungstate), ABA-deficient tomato mutants (notabilis, flacca, and sitiens), and quantification of xanthophylls indicate that ABA biosynthesis is influenced, probably through stimulated cleavage of xanthophylls to xanthoxal in shoot tissue. PMID:11080318

Hansen, Hauke; Grossmann, Klaus

2000-01-01

8

Calcite crystal growth inhibition by humic substances with emphasis on hydrophobic acids from the Florida Everglades  

USGS Publications Warehouse

The crystallization of calcium carbonate minerals plays an integral role in the water chemistry of terrestrial ecosystems. Humic substances, which are ubiquitous in natural waters, have been shown to reduce or inhibit calcite crystal growth in experiments. The purpose of this study is to quantify and understand the kinetic effects of hydrophobic organic acids isolated from the Florida Everglades and a fulvic acid from Lake Fryxell, Antarctica, on the crystal growth of calcite (CaCO3). Highly reproducible calcite growth experiments were performed in a sealed reactor at constant pH, temperature, supersaturation (?? = 4.5), P(CO2) (10-3.5atm), and ionic strength (0.1 M) with various concentrations of organic acids. Higher plant-derived aquatic hydrophobic acids from the Everglades were more effective growth inhibitors than microbially derived fulvic acid from Lake Fryxell. Organic acid aromaticity correlated strongly with growth inhibition. Molecular weight and heteroatom content correlated well with growth inhibition, whereas carboxyl content and aliphatic nature did not. Copyright (C) 1999 Elsevier Science Ltd.

Hoch, A. R.; Reddy, M. M.; Aiken, G. R.

2000-01-01

9

Galacturonic Acid Inhibits the Growth of Saccharomyces cerevisiae on Galactose, Xylose, and Arabinose  

PubMed Central

The efficient fermentation of mixed substrates is essential for the microbial conversion of second-generation feedstocks, including pectin-rich waste streams such as citrus peel and sugar beet pulp. Galacturonic acid is a major constituent of hydrolysates of these pectin-rich materials. The yeast Saccharomyces cerevisiae, the main producer of bioethanol, cannot use this sugar acid. The impact of galacturonic acid on alcoholic fermentation by S. cerevisiae was investigated with anaerobic batch cultures grown on mixtures of glucose and galactose at various galacturonic acid concentrations and on a mixture of glucose, xylose, and arabinose. In cultures grown at pH 5.0, which is well above the pKa value of galacturonic acid (3.51), the addition of 10 g · liter?1 galacturonic acid did not affect galactose fermentation kinetics and growth. In cultures grown at pH 3.5, the addition of 10 g · liter?1 galacturonic acid did not significantly affect glucose consumption. However, at this lower pH, galacturonic acid completely inhibited growth on galactose and reduced galactose consumption rates by 87%. Additionally, it was shown that galacturonic acid strongly inhibits the fermentation of xylose and arabinose by the engineered pentose-fermenting S. cerevisiae strain IMS0010. The data indicate that inhibition occurs when nondissociated galacturonic acid is present extracellularly and corroborate the hypothesis that a combination of a decreased substrate uptake rate due to competitive inhibition on Gal2p, an increased energy requirement to maintain cellular homeostasis, and/or an accumulation of galacturonic acid 1-phosphate contributes to the inhibition. The role of galacturonic acid as an inhibitor of sugar fermentation should be considered in the design of yeast fermentation processes based on pectin-rich feedstocks. PMID:22582063

Huisjes, Eline H.; de Hulster, Erik; van Dam, Jan C.; Pronk, Jack T.

2012-01-01

10

Influence of Medium Buffering Capacity on Inhibition of Saccharomyces cerevisiae Growth by Acetic and Lactic Acids  

PubMed Central

Acetic acid (167 mM) and lactic acid (548 mM) completely inhibited growth of Saccharomyces cerevisiae both in minimal medium and in media which contained supplements, such as yeast extract, corn steep powder, or a mixture of amino acids. However, the yeast grew when the pH of the medium containing acetic acid or lactic acid was adjusted to 4.5, even though the medium still contained the undissociated form of either acid at a concentration of 102 mM. The results indicated that the buffer pair formed when the pH was adjusted to 4.5 stabilized the pH of the medium by sequestering protons and by lessening the negative impact of the pH drop on yeast growth, and it also decreased the difference between the extracellular and intracellular pH values (?pH), the driving force for the intracellular accumulation of acid. Increasing the undissociated acetic acid concentration at pH 4.5 to 163 mM by raising the concentration of the total acid to 267 mM did not increase inhibition. It is suggested that this may be the direct result of decreased acidification of the cytosol because of the intracellular buffering by the buffer pair formed from the acid already accumulated. At a concentration of 102 mM undissociated acetic acid, the yeast grew to higher cell density at pH 3.0 than at pH 4.5, suggesting that it is the total concentration of acetic acid (104 mM at pH 3.0 and 167 mM at pH 4.5) that determines the extent of growth inhibition, not the concentration of undissociated acid alone. PMID:11916676

Thomas, K. C.; Hynes, S. H.; Ingledew, W. M.

2002-01-01

11

Epoxy metabolites of docosahexaenoic acid (DHA) inhibit angiogenesis, tumor growth, and metastasis  

E-print Network

in circulation, caus- ing 70% inhibition of primary tumor growth and metastasis. Con- trary to the effects of angiogenic diseases such as macular degeneration (1­4) and cancers (5­8). However, the mechanisms by which of omega-3 fatty acids by cyclooxygenase (COX) and lipoxygenase (LOX) enzymes generates 3-series pros

Hammock, Bruce D.

12

Fatty acids and monoacylglycerols inhibit growth of Staphylococcus aureus  

Microsoft Academic Search

Staphylococcus aureus causes a variety of human infections including toxic shock syndrome, osteomyelitis, and mastitis. Mastitis is a common disease\\u000a in the dairy cow, andS. aureus has been found to be a major infectious organism causing mastitis. The objectives of this research were to determine which\\u000a FA and esterified forms of FA were inhibitory to growth ofS. aureus bacteria. FA

J. A. Kelsey; K. W. Bayles; B. Shafii; M. A. McGuire

2006-01-01

13

Quantitative Analysis of the Modes of Growth Inhibition by Weak Organic Acids in Saccharomyces cerevisiae  

PubMed Central

Weak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pHi) in Saccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell's ability to restore pHi, was a determinant for growth inhibition. This pHi recovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pHi, and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pHi upon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport. PMID:23001666

Ullah, Azmat; Orij, Rick; Brul, Stanley

2012-01-01

14

Epoxy metabolites of docosahexaenoic acid (DHA) inhibit angiogenesis, tumor growth, and metastasis  

PubMed Central

Epidemiological and preclinical evidence supports that omega-3 dietary fatty acids (fish oil) reduce the risks of macular degeneration and cancers, but the mechanisms by which these omega-3 lipids inhibit angiogenesis and tumorigenesis are poorly understood. Here we show that epoxydocosapentaenoic acids (EDPs), which are lipid mediators produced by cytochrome P450 epoxygenases from omega-3 fatty acid docosahexaenoic acid, inhibit VEGF- and fibroblast growth factor 2-induced angiogenesis in vivo, and suppress endothelial cell migration and protease production in vitro via a VEGF receptor 2-dependent mechanism. When EDPs (0.05 mg?kg?1?d?1) are coadministered with a low-dose soluble epoxide hydrolase inhibitor, EDPs are stabilized in circulation, causing ?70% inhibition of primary tumor growth and metastasis. Contrary to the effects of EDPs, the corresponding metabolites derived from omega-6 arachidonic acid, epoxyeicosatrienoic acids, increase angiogenesis and tumor progression. These results designate epoxyeicosatrienoic acids and EDPs as unique endogenous mediators of an angiogenic switch to regulate tumorigenesis and implicate a unique mechanistic linkage between omega-3 and omega-6 fatty acids and cancers. PMID:23553837

Zhang, Guodong; Panigrahy, Dipak; Mahakian, Lisa M.; Yang, Jun; Liu, Jun-Yan; Stephen Lee, Kin Sing; Wettersten, Hiromi I.; Ulu, Arzu; Hu, Xiaowen; Tam, Sarah; Hwang, Sung Hee; Ingham, Elizabeth S.; Kieran, Mark W.; Weiss, Robert H.; Ferrara, Katherine W.; Hammock, Bruce D.

2013-01-01

15

Inhibition of Parietal Cell Acid Secretion Is Mediated by the Classical Epidermal Growth Factor Receptor  

Microsoft Academic Search

Epidermal growth factor (EGF) and transforminggrowth factor-a (TGF-a) inhibit gastric acidsecretion both in vivo and in vitro. Previous studieshave indicated that EGF and TGF-a bind to the same EGF\\/TGF-a receptor. Nevertheless, weand others have previously demonstrated that inhibitionof acid secretion by these growth factors requiresconcentrations of the peptides that are 10-fold higher than those necessary for induction ofmitogenesis. Therefore, we

Virendra Joshi; Gregory S. Ray; James R. Goldenring

1997-01-01

16

Peptide nucleic acids inhibit growth of Brucella suis in pure culture and in infected murine macrophages  

PubMed Central

Peptide nucleic acids (PNAs) are single-stranded, synthetic nucleic acid analogues containing a pseudopeptide backbone in place of the phosphodiester sugar–phosphate. When PNAs are covalently linked to cell-penetrating peptides (CPPs) they readily penetrate the bacterial cell envelope, inhibit expression of targeted genes and cause growth inhibition both of Gram-positive and Gram-negative bacteria. However, the effectiveness of PNAs against Brucella, a facultative intracellular bacterial pathogen, was unknown. The susceptibility of a virulent Brucella suis strain to a variety of PNAs was assessed in pure culture as well as in murine macrophages. The studies showed that some of the PNAs targeted to Brucella genes involved in DNA (polA, dnaG, gyrA), RNA (rpoB), cell envelope (asd), fatty acid (kdtA, acpP) and protein (tsf) synthesis inhibit the growth of B. suis in culture and in macrophages after 24 h of treatment. PNA treatment inhibited Brucella growth by interfering with gene expression in a sequence-specific and dose-dependent manner at micromolar concentrations. The most effective PNA in broth culture was that targeting polA at ca. 12 ?M. In contrast, in B. suis-infected macrophages, the most effective PNAs were those targeting asd and dnaG at 30 ?M; both of these PNAs had little inhibitory effect on Brucella in broth culture. The polA PNA that inhibits wild-type B. suis also inhibits the growth of wild-type Brucella melitensis 16M and Brucella abortus 2308 in culture. This study reveals the potential usefulness of antisense PNA constructs as novel therapeutic agents against intracellular Brucella. PMID:23305655

Rajasekaran, Parthiban; Alexander, Jeffry C.; Seleem, Mohamed N.; Jain, Neeta; Sriranganathan, Nammalwar; Wattam, Alice R.; Setubal, Joao C.; Boyle, Stephen M.

2012-01-01

17

Calcium Antagonists Inhibit Sustained Gibberellic Acid-Induced Growth of Avena (Oat) Stem Segments.  

PubMed Central

The elongation response of Avena sativa (oat) stem segments to gibberellic acid (GA3) is of large magnitude, with high hormonal sensitivity and specificity, but without cell division activity. This system is therefore an excellent model for mechanistic studies on higher plant cell elongation and the action of gibberellin. At millimolar concentrations, the calcium antagonists verapamil, D-600, nicardipine, diltiazem, bepridil, 8-(N,N,-diethylamino)-octyl-3,4,5-trimethoxybenzoate HCl, and lanthanum substantially inhibited the growth of GA3-treated segments but had no effect on the elongation of nonhormone-treated segments. Although verapamil reduced the maximum growth rate and caused premature cessation of growth, even preincubation of the segments with the drug prior to treatment with GA3 failed to inhibit the earliest measured stimulation of growth by the hormone. Inhibition by verapamil was not reversed by increased concentrations of GA3 or calcium. Neither the calcium ionophore A23187 nor agonist BAY K 8644 had any effect on growth. Light microscopic examination of epidermal peels from antagonist-treated internodal tissue revealed no obvious differences from the control except that the cells were not as elongated. Although these results may support a role for calcium ion movement in maintaining the GA3-induced growth of Avena stem segments, they do not support the involvement of calcium ion movement in the hormone-mediated initiation of growth. PMID:12231695

Montague, M. J.

1993-01-01

18

The inhibition of bacterial growth by hypochlorous acid. Possible role in the bactericidal activity of phagocytes.  

PubMed Central

The 'respiratory burst' of phagocytes such as neutrophils generates superoxide which forms H2O2 by dismutation. H2O2 and Cl- ions serve as substrates for the enzyme myeloperoxidase to generate hypochlorous acid (HOCl). HOCl is thought to play an important role in bacterial killing, but its mechanism of action is not well characterized. Furthermore, although many studies in vitro have shown HOCl to be a damaging oxidant with little or no specificity (particularly at high concentrations), bacteria which have been ingested by phagocytes appear to experience a rapid and selective inhibition of cell division. Bacterial membrane disruption, protein degradation, and inhibition of protein synthesis, do not seem to occur in the early phases of phagocyte action. We have now found that low concentrations of HOCl exert a rapid and selective inhibition of bacterial growth and cell division, which can be blocked by taurine or amino acids. Only 20 microM-HOCl was required for 50% inhibition of bacterial growth (5 x 10(8) Escherichia coli/ml), and 50 microM-HOCl completely inhibited cell division (colony formation). These effects were apparent within 5 min of HOCl exposure, and were not reversed by extensive washings. DNA synthesis (incorporation of [3H]-thymidine) was significantly affected by even a 1 min exposure to 50 microM-HOCl, and decreased by as much as 96% after 5 min. In contrast, bacterial membrane disruption and extensive protein degradation/fragmentation (release of acid-soluble counts from [3H]leucine-labelled cells) were not observed at concentrations below 5 mM-HOCl. Protein synthesis (incorporation of [3H]leucine) was only inhibited by 10-30% following 5 min exposure to 50 microM-HOCl, although longer exposure produced more marked reductions (80% after 30 min). Neutrophils deficient in myeloperoxidase cannot convert H2O2 to HOCl, yet can kill bacteria. We have found that H2O2 is only 6% as effective as HOCl in inhibiting E. coli growth and cell division (0.34 mM-H2O2 required for 50% inhibition of colony formation), and taurine or amino acids do not block this effect. Our results are consistent with a rapid and selective inhibition of bacterial cell division by HOCl in phagocytes. H2O2 may substitute for HOCl in myeloperoxidase deficiency, but by a different mechanism and at a greater metabolic cost. PMID:2848494

McKenna, S M; Davies, K J

1988-01-01

19

Selective growth inhibition of human malignant melanoma cells by syringic acid-derived proteasome inhibitors  

PubMed Central

Background It has been shown that proteasome inhibition leads to growth arrest in the G1 phase of the cell cycle and/or induction of apoptosis. However, it was found that some of these inhibitors do not induce apoptosis in several human normal cell lines. This selective activity makes proteasome inhibition a promising target for new generation of anticancer drugs. Clinical validation of the proteasome, as a therapeutic target in oncology, has been provided by the dipeptide boronic acid derivative; bortezomib. Bortezomib has proven to be effective as a single agent in multiple myeloma and some forms of non-Hodgkin’s lymphoma. Syringic acid (4-hydroxy-3,5-dimethoxybenzoic acid, 1), a known phenolic acid, was isolated from the methanol extract of Tamarix aucheriana and was shown to possess proteasome inhibitory activity. Methods Using Surflex-Dock program interfaced with SYBYL, the docking affinities of syringic acid and its proposed derivatives to 20S proteasome were studied. Several derivatives were virtually proposed, however, five derivatives: benzyl 4-hydroxy-3,5-dimethoxybenzoate (2), benzyl 4-(benzyloxy)-3,5-dimethoxybenzoate (3), 3'-methoxybenzyl 3,5-dimethoxy-4-(3'-methoxybenzyloxy)benzoate (4), 3'-methoxybenzyl 4-hydroxy-3,5-dimethoxybenzoate (5) and 3',5'-dimethoxybenzyl 4-hydroxy-3,5-dimethoxybenzoate (6), were selected based on high docking scores, synthesized, and tested for their anti-mitogenic activity against human colorectal, breast and malignant melanoma cells as well as normal human fibroblast cells. Results Derivatives 2, 5, and 6 showed selective dose-dependent anti-mitogenic effect against human malignant melanoma cell lines HTB66 and HTB68 with minimal cytotoxicity on colorectal and breast cancer cells as well as normal human fibroblast cells. Derivatives 2, 5 and 6 significantly (p???0.0001) inhibited the various proteasomal chymotrypsin, PGPH, and trypsin like activities. They growth arrested the growth of HTB66 cells at G1 and G2-phases. They also arrested the growth of HTB68 cells at S- and G2-phase, respectively. Moreover, derivatives 2, 5, and 6 markedly induced apoptosis (? 90%) in both HTB66 and HTB68. Conclusions Computer-derived syringic acid derivatives possess selective anti-mitogenic activity on human malignant melanoma cells that may be attributed to perturbation of cell cycle, induction of apoptosis and inhibition of various 26S proteasomal activities. PMID:23958424

2013-01-01

20

Exogenous Salicylic Acid Alleviates Growth Inhibition and Oxidative Stress Induced by Hypoxia Stress in Malus robusta Rehd  

Microsoft Academic Search

Salicylic acid (SA) as a signal molecule mediates many biotic and environmental stress-induced physiologic responses in plants.\\u000a In this study we investigated the role of SA in regulating growth and oxidative stress in Malus robusta Rehd under both normoxic and hypoxic conditions. Hypoxia stress inhibited plant growth and dramatically reduced biomass.\\u000a Addition of SA significantly alleviated the plant growth inhibition.

Tuanhui Bai; Cuiying Li; Fengwang Ma; Huairui Shu; Mingyu Han

2009-01-01

21

Metalloporphyrin synergizes with ascorbic acid to inhibit cancer cell growth through fenton chemistry.  

PubMed

Ascorbic acid (AA) has been reported to inhibit tumor cell growth through the generation of extracellular hydrogen peroxide (H(2)O(2)). However, the clinical utility of AA has been limited by relatively low potency and in vivo efficacy. This study reports that the metalloporphyrin, Mn(III) tetrakis(N-methylpyridinium-2-yl)porphyrin(5+) (MnTMPyP), has a potent synergistic cytotoxic effect when combined with AA in a variety of cancer cell lines. In the presence of MnTMPyP, the concentration of AA required to inhibit cancer cell growth was markedly reduced. In vitro (cell-free) experiments demonstrated that AA alone enhanced the Fenton reaction that produces cytotoxic hydroxyl radical (HO(*)); however, this reaction was limited by the low rate by which AA generates H(2)O(2) (Fenton reaction substrate) from O(2). MnTMPyP catalyzed H(2)O(2) generation through the AA-facilitated Mn(II <--> III)TMPyP redox cycle and thereby markedly potentiated the Fenton reaction. Accordingly, MnTMPyP and AA resulted in increased cellular levels of H(2)O(2) and HO(*) in cancer cells, which mediate the synergistic cytotoxicity of this combined treatment. This effect was inhibited by cellular enzymes that metabolize H(2)O(2), such as catalase and glutathione peroxidase, suggesting that selective killing of cancer cells deficient in such enzymes can be achieved in vivo. PMID:20735206

Tian, Junqiang; Peehl, Donna M; Knox, Susan J

2010-08-01

22

Calcite growth-rate inhibition by fulvic acids isolated from Big Soda Lake, Nevada, USA, The Suwannee River, Georgia, USA and by polycarboxylic acids  

USGS Publications Warehouse

Calcite crystallization rates are characterized using a constant solution composition at 25°C, pH=8.5, and calcite supersaturation (?) of 4.5 in the absence and presence of fulvic acids isolated from Big Soda Lake, Nevada (BSLFA), and a fulvic acid from the Suwannee River, Georgia (SRFA). Rates are also measured in the presence and absence of low-molar mass, aliphatic-alicyclic polycarboxylic acids (PCA). BSLFA inhibits calcite crystal-growth rates with increasing BSLFA concentration, suggesting that BSLFA adsorbs at growth sites on the calcite crystal surface. Calcite growth morphology in the presence of BSLFA differed from growth in its absence, supporting an adsorption mechanism of calcite-growth inhibition by BSLFA. Calcite growth-rate inhibition by BSLFA is consistent with a model indicating that polycarboxylic acid molecules present in BSLFA adsorb at growth sites on the calcite crystal surface. In contrast to published results for an unfractionated SRFA, there is dramatic calcite growth inhibition (at a concentration of 1 mg/L) by a SRFA fraction eluted by pH 5 solution from XAD-8 resin, indicating that calcite growth-rate inhibition is related to specific SRFA component fractions. A cyclic PCA, 1, 2, 3, 4, 5, 6-cyclohexane hexacarboxylic acid (CHXHCA) is a strong calcite growth-rate inhibitor at concentrations less than 0.1 mg/L. Two other cyclic PCAs, 1, 1 cyclopentanedicarboxylic acid (CPDCA) and 1, 1 cyclobutanedicarboxylic acid (CBDCA) with the carboxylic acid groups attached to the same ring carbon atom, have no effect on calcite growth rates up to concentrations of 10 mg/L. Organic matter ad-sorbed from the air onto the seed crystals has no effect on the measured calcite crystal-growth rates.

Reddy, Michael M.; Leenheer, Jerry

2011-01-01

23

Inhibited growth of Pseudomonas aeruginosa by dextran- and polyacrylic acid-coated ceria nanoparticles  

PubMed Central

Ceria (CeO2) nanoparticles have been widely studied for numerous applications, but only a few recent studies have investigated their potential applications in medicine. Moreover, there have been almost no studies focusing on their possible antibacterial properties, despite the fact that such nanoparticles may reduce reactive oxygen species. In this study, we coated CeO2 nanoparticles with dextran or polyacrylic acid (PAA) because of their enhanced biocompatibility properties, minimized toxicity, and reduced clearance by the immune system. For the first time, the coated CeO2 nanoparticles were tested in bacterial assays involving Pseudomonas aeruginosa, one of the most significant bacteria responsible for infecting numerous medical devices. The results showed that CeO2 nanoparticles with either coating significantly inhibited the growth of Pseudomonas aeruginosa, by up to 55.14%, after 24 hours compared with controls (no particles). The inhibition of bacterial growth was concentration dependent. In summary, this study revealed, for the first time, that the characterized dextran- and PAA-coated CeO2 nanoparticles could be potential novel materials for numerous antibacterial applications. PMID:24039421

Wang, Qi; Perez, J Manuel; Webster, Thomas J

2013-01-01

24

Calcite growth-rate inhibition by fulvic acid and magnesium ion—Possible influence on biogenic calcite formation  

USGS Publications Warehouse

Increases in ocean surface water dissolved carbon dioxide (CO2) concentrations retard biocalcification by reducing calcite supersaturation (?c). Reduced calcification rates may influence growth-rate dependent magnesium ion (Mg) incorporation into biogenic calcite modifying the use of calcifying organisms as paleoclimate proxies. Fulvic acid (FA) at biocalcification sites may further reduce calcification rates. Calcite growth-rate inhibition by FA and Mg, two common constituents of seawater and soil water involved in the formation of biogenic calcite, was measured separately and in combination under identical, highly reproducible experimental conditions. Calcite growth rates (pH=8.5 and ?c=4.5) are reduced by FA (0.5 mg/L) to 47% and by Mg (10?4 M) to 38%, compared to control experiments containing no added growth-rate inhibitor. Humic acid (HA) is twice as effective a calcite growth-rate inhibitor as FA. Calcite growth rate in the presence of both FA (0.5 mg/L) and Mg (10?4 M) is reduced to 5% of the control rate. Mg inhibits calcite growth rates by substitution for calcium ion at the growth site. In contrast, FA inhibits calcite growth rates by binding multiple carboxylate groups on the calcite surface. FA and Mg together have an increased affinity for the calcite growth sites reducing calcite growth rates.

Reddy, Michael M.

2012-01-01

25

Colorectal cancer cell growth inhibition by linoleic acid is related to fatty acid composition changes  

Microsoft Academic Search

Polyunsaturated fatty acids (PUFAs) possess anti-cancer action both in vitro and in vivo. In the present study, we detected\\u000a cell viability with methyl thiazolyl tetrazolium (MTT) assay and cell membrane permeability with propidium iodide (PI) fluorescence\\u000a dyeing, and calculated cell membrane fluidity change as fluorescence anisotropy. Fatty acid content in cells was measured\\u000a by gas chromatography\\/mass spectroscopy (GC\\/MS), and the

Xiao-feng Lu; Guo-qing He; Hai-ning Yu; Qi Ma; Sheng-rong Shen; Undurti N. Das

2010-01-01

26

Enhanced Lignin Monomer Production Caused by Cinnamic Acid and Its Hydroxylated Derivatives Inhibits Soybean Root Growth  

PubMed Central

Cinnamic acid and its hydroxylated derivatives (p-coumaric, caffeic, ferulic and sinapic acids) are known allelochemicals that affect the seed germination and root growth of many plant species. Recent studies have indicated that the reduction of root growth by these allelochemicals is associated with premature cell wall lignification. We hypothesized that an influx of these compounds into the phenylpropanoid pathway increases the lignin monomer content and reduces the root growth. To confirm this hypothesis, we evaluated the effects of cinnamic, p-coumaric, caffeic, ferulic and sinapic acids on soybean root growth, lignin and the composition of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) monomers. To this end, three-day-old seedlings were cultivated in nutrient solution with or without allelochemical (or selective enzymatic inhibitors of the phenylpropanoid pathway) in a growth chamber for 24 h. In general, the results showed that 1) cinnamic, p-coumaric, caffeic and ferulic acids reduced root growth and increased lignin content; 2) cinnamic and p-coumaric acids increased p-hydroxyphenyl (H) monomer content, whereas p-coumaric, caffeic and ferulic acids increased guaiacyl (G) content, and sinapic acid increased sinapyl (S) content; 3) when applied in conjunction with piperonylic acid (PIP, an inhibitor of the cinnamate 4-hydroxylase, C4H), cinnamic acid reduced H, G and S contents; and 4) when applied in conjunction with 3,4-(methylenedioxy)cinnamic acid (MDCA, an inhibitor of the 4-coumarate:CoA ligase, 4CL), p-coumaric acid reduced H, G and S contents, whereas caffeic, ferulic and sinapic acids reduced G and S contents. These results confirm our hypothesis that exogenously applied allelochemicals are channeled into the phenylpropanoid pathway causing excessive production of lignin and its main monomers. By consequence, an enhanced stiffening of the cell wall restricts soybean root growth. PMID:24312480

Lima, Rogerio Barbosa; Salvador, Victor Hugo; dos Santos, Wanderley Dantas; Bubna, Gisele Adriana; Finger-Teixeira, Aline; Soares, Anderson Ricardo; Marchiosi, Rogerio; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

2013-01-01

27

Naphthenic acids inhibit root water transport, gas exchange and leaf growth in aspen (Populus tremuloides) seedlings.  

PubMed

Effects of sodium naphthenates (NAs) on root hydraulic conductivity (Lp) and gas exchange processes were examined in aspen (Populus tremuloides Michx.) seedlings grown in solution culture. Exposure of roots to NAs for 3-5 weeks significantly decreased Lp and stomatal conductance. Root-absorbed NAs also decreased leaf chlorophyll concentration, net photosynthesis and leaf growth. Short-term (< or = 2 h) exposure of excised roots to NAs significantly decreased root water flow (Qv) with a concomitant decline in root respiration. We conclude that NAs metabolically inhibited Lp, likely by affecting water channel activity, and that this inhibition could be responsible for the observed reductions in gas exchange and leaf growth. PMID:12464580

Kamaluddin, M; Zwiazek, Janusz J

2002-12-01

28

Inhibition of Translation and Bacterial Growth by Peptide Nucleic Acid Targeted to Ribosomal RNA  

Microsoft Academic Search

Peptide nucleic acid (PNA) is a DNA mimic that has shown considerable promise as a lead compound for developing gene therapeutic drugs. We report that PNAs targeted to functional and accessible sites in ribosomal RNA can inhibit translation in an Escherichia coli cell-free transcription\\/translation system, with 50% reductions caused by nanomolar PNA concentrations. The effect in vitro is quantitatively similar

Liam Good; Peter E. Nielsen

1998-01-01

29

Combination of Phenylbutyrate and 13-cis Retinoic Acid Inhibits Prostate Tumor Growth and Angiogenesis1  

Microsoft Academic Search

Differentiation-inducing agents, such as retinoids and short-chain fatty acids, have an inhibitory effect on tumor cell proliferation and tumor growth in preclinical studies. Clinical trials involving these compounds as single agents have been suboptimal in terms of clinical benefit. Our study evaluated the combination of phenylbutyrate (PB) and 13-cis retinoic acid (CRA) as a differentiation and antiangiogenesis strategy for prostate

Roberto Pili; Mark P. Kruszewski; Brant W. Hager; Julie Lantz; Michael A. Carducci

2001-01-01

30

Induction of mammary differentiation by mammary-derived growth inhibitor-related gene that interacts with an omega-3 fatty acid on growth inhibition of breast cancer cells.  

PubMed

We previously identified and characterized a novel tumor growth inhibitor and a fatty acid-binding protein in human mammary gland and named it the mammary-derived growth inhibitor-related gene (MRG). Here, the effects of MRG on mammary gland differentiation and its interaction with omega-3 polyunsaturated fatty acids (omega-3 PUFAs) on growth inhibition were investigated. MRG protein expression was associated with human mammary gland differentiation, with the highest expression observed in the differentiated alveolar mammary epithelial cells from the lactating gland. Overexpression of MRG in human breast cancer cells induced differentiation with changes in cellular morphology and a significant increase in the production of lipid droplets. Treatment of mouse mammary gland in organ culture with MRG protein resulted in a differentiated morphology and stimulation of beta-casein expression. Treatment of human breast cancer cells with the omega-3 PUFA docosahexaenoic acid resulted in a differential growth inhibition proportional to their MRG expression. MRG-transfected cells or MRG protein treated cells were much more sensitive to docosahexaenoic acid-induced growth inhibition than MRG-negative or untreated control cells. Our results suggest that MRG is a candidate mediator of the differentiating effect of pregnancy on breast epithelial cells and may play a major role in omega-3 PUFA-mediated tumor suppression. PMID:11103817

Wang, M; Liu, Y E; Ni, J; Aygun, B; Goldberg, I D; Shi, Y E

2000-11-15

31

Acid precipitation and food quality: Inhibition of growth and survival in black ducks and mallards by dietary aluminum, calcium, and phosphorus  

Microsoft Academic Search

In areas impacted by acid precipitation, water chemistry of acidic ponds and streams often changes, resulting in increased mobilization of aluminum and decreased concentration of calcium carbonate. Aluminum binds with phosphorus and inhibits its uptake by organisms. Thus, invertebrate food organisms used by waterfowl may have inadequate Ca and P or elevated Al for normal growth and development. Acid rain

Donald W. Sparling

1990-01-01

32

Phosphorylation of InhA inhibits mycolic acid biosynthesis and growth of Mycobacterium tuberculosis  

SciTech Connect

The remarkable survival ability of Mycobacterium tuberculosis in infected hosts is related to the presence of cell wall-associated mycolic acids. Despite their importance, the mechanisms that modulate expression of these lipids in response to environmental changes are unknown. Here we demonstrate that the enoyl-ACP reductase activity of InhA, an essential enzyme of the mycolic acid biosynthetic pathway and the primary target of the anti-tubercular drug isoniazid, is controlled via phosphorylation. Thr-266 is the unique kinase phosphoacceptor, both in vitro and in vivo. The physiological relevance of Thr-266 phosphorylation was demonstrated using inhA phosphoablative (T266A) or phosphomimetic (T266D/E) mutants. Enoyl reductase activity was severely impaired in the mimetic mutants in vitro, as a consequence of a reduced binding affinity to NADH. Importantly, introduction of inhA{_}T266D/E failed to complement growth and mycolic acid defects of an inhA-thermosensitive Mycobacterium smegmatis strain, in a similar manner to what is observed following isoniazid treatment. This study suggests that phosphorylation of InhA may represent an unusual mechanism that allows M. tuberculosis to regulate its mycolic acid content, thus offering a new approach to future anti-tuberculosis drug development.

Molle, Virginie; Gulten, Gulcin; Vilchèze, Catherine; Veyron-Churlet, Romain; Zanella-Cléon, Isabelle; Sacchettini, James C.; Jacobs, Jr, William R.; Kremer, Laurent (CNRS-UMR); (Einstein); (TAM)

2011-08-24

33

Tolerance of transgenic canola expressing 1-aminocyclopropane-1-carboxylic acid deaminase to growth inhibition by nickel.  

PubMed

Plant growth-promoting bacteria are useful to phytoremediation strategies in that they confer advantages to plants in contaminated soil. When plant growth-promoting bacteria contain the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, the bacterial cell acts as a sink for ACC, the immediate biosynthetic precursor of the plant growth regulator ethylene thereby lowering plant ethylene levels and decreasing the negative effects of various environmental stresses. In an effort to gain the advantages provided by bacterial ACC deaminase in the phytoremediation of metals from the environment two transgenic canola lines with the gene for this enzyme were generated and tested. In these transgenic canola plants, expression of the ACC deaminase gene is driven by either tandem constitutive cauliflower mosaic virus (CaMV) 35S promoters or the root specific rolD promoter from Agrobacterium rhizogenes. Following the growth of transgenic and non-transformed canola in nickel contaminated soil, it was observed that the rolD plants demonstrate significantly increased tolerance to nickel compared to the non-transformed control plants. PMID:16023358

Stearns, Jennifer C; Shah, Saleh; Greenberg, Bruce M; Dixon, D George; Glick, Bernard R

2005-07-01

34

Inhibition of apatite crystal growth by the amino-terminal segment of human salivary acidic proline-rich proteins  

Microsoft Academic Search

Summary  Inhibition of seeded apatitic crystal growth by human salivary acidic proline-rich phosphoproteins (PRP) has been related\\u000a to their adsorption onto the apatite seeds. The amino-terminal 30-residue segment of the PRP makes an important contribution\\u000a to this adsorption. This peptide (PRP1(T1)) and its dephosphorylated analogue from PRP3 (PRP3(T1)DP) were prepared. They have\\u000a identical sequences, except the phosphates at residues 8 and

T. Aoba; E. C. Moreno; D. I. Hay

1984-01-01

35

All-Trans Retinoic Acid Stimulates Growth and Extracellular Matrix Production in Growth-Inhibited Cultured Human Skin Fibroblasts  

Microsoft Academic Search

All-trans retinoic acid was examined for effects on human dermal fibroblast proliferation and for effects on fibroblast production and expression of non-collagenous and collagenous components of the extracellular matrix in vitro. Fibroblast proliferation was blocked when the cells were cultured in the presence of a serum-free culture medium containing epidermal growth factor, hydrocortisone, insulin, ethanolamine, phosphoethanolamine, and bovine pituitary extract

James Varani; Raj S. Mitra; Douglas Gibbs; Sem H. Phan; Vishva M. Dixit; Rajorshi Mitra Jr.; Tamara Wang; Karl J. Siebert; Brian J. Nickoloff; John J. Voorhees

1990-01-01

36

Bile acids inhibit Mcl-1 protein turnover via an epidermal growth factor receptor/Raf-1-dependent mechanism.  

PubMed

Bile acids have been implicated in biliary tract carcinogenesis, in part, by activating the epidermal growth factor receptor (EGFR). Overexpression of Mcl-1, a potent antiapoptotic protein of the Bcl-2 family, has also been reported in cholangiocarcinomas. Because receptor tyrosine kinases like EGFR may modulate antiapoptotic protein expression, we examined the hypothesis that bile acids modulate Mcl-1 expression levels via EGFR. Deoxycholate increased cellular Mcl-1 protein in a concentration-dependent manner. The deoxycholate-mediated increase of cellular Mcl-1 protein was blocked equally by EGFR tyrosine kinase inhibitors or an EGFR-neutralizing antibody. Although inhibition of mitogen-activated protein kinases did not attenuate the deoxycholate-associated increase in Mcl-1 protein, the Raf-1 inhibitor, BAY 37-9751, effectively blocked the cellular increase of this protein. Neither Mcl-1 transcriptional activity nor its mRNA stability was altered by deoxycholate treatment. However, Mcl-1 protein stability was increased by bile acid treatment, an effect duplicated by proteasome inhibition. Deoxycholate prolongation of Mcl-1 turnover was blocked by either EGFR inhibitors or the Raf-1 inhibitor. Whereas the deoxycholate-induced increase in Mcl-1 reduced Fas-mediated apoptosis, the Raf-1 inhibitor potentiated Fas apoptosis. Our results demonstrate that bile acids block Mcl-1 protein degradation via activation of an EGFR/Raf-1 cascade resulting in its cellular accumulation. Raf-1 inhibitors block this increase of Mcl-1 and render the cells more susceptible to apoptosis, a potential therapeutic strategy for cholangiocarcinomas. PMID:12438243

Yoon, Jung-Hwan; Werneburg, Nathan W; Higuchi, Hajime; Canbay, Ali E; Kaufmann, Scott H; Akgul, Cahit; Edwards, Steven W; Gores, Gregory J

2002-11-15

37

High levels of jasmonic acid antagonize the biosynthesis of gibberellins and inhibit the growth of Nicotiana attenuata stems.  

PubMed

Hormones play pivotal roles in regulating plant development, growth, and stress responses, and cross-talk among different hormones fine-tunes various aspects of plant physiology. Jasmonic acid (JA) is important for plant defense against herbivores and necrotic fungi and also regulates flower development; in addition, Arabidopsis mutants over-producing JA usually have stunted stems and wound-induced jasmonates suppress Arabidopsis growth, suggesting that JA is also involved in stem elongation. Gibberellins (GAs) promote stem and leaf growth and modulate seed germination, flowering time, and the development of flowers, fruits, and seeds. However, little is known about the interaction between the JA and GA pathways. Two calcium-dependent protein kinases, CDPK4 and CDPK5, are important suppressors of JA accumulation in a wild tobacco species, Nicotiana attenuata. The stems of N. attenuata silenced in CDPK4 and CDPK5 (irCDPK4/5 plants) had dramatically increased levels of JA and exhibited stunted elongation and had very high contents of secondary metabolites. Genetic analysis indicated that the high JA levels in irCDPK4/5 stems accounted for the suppressed stem elongation and the accumulation of secondary metabolites. Supplementation of GA(3) to irCDPK4/5 plants largely restored normal stem growth to wild-type levels. Measures of GA levels indicated that over-accumulation of JA in irCDPK4/5 stems inhibited the biosynthesis of GAs. Finally, we show that JA antagonizes GA biosynthesis by strongly inhibiting the transcript accumulation of GA20ox and possibly GA13ox, the key genes in GA production, demonstrating that high JA levels antagonize GA biosynthesis in stems. PMID:23190261

Heinrich, Maria; Hettenhausen, Christian; Lange, Theo; Wünsche, Hendrik; Fang, Jingjing; Baldwin, Ian T; Wu, Jianqiang

2013-02-01

38

Xylitol inhibition of acid production and growth of mutans Streptococci in the presence of various dietary sugars under strictly anaerobic conditions.  

PubMed

The aim of this study was to investigate the inhibitory effect of xylitol on the growth of and acid production by mutans streptococci in the presence of various dietary sugars, and the relationship between the inhibition and the accumulation of xylitol 5-phosphate (X5P) under strictly anaerobic conditions like those in the deep layers of dental plaque. Xylitol retarded the growth of mutans streptococci in the presence of glucose (G), galactose (Gal), maltose (M), lactose (L) or sucrose (S) as an energy source, though the inhibition of growth on fructose (Fr) was small. Xylitol inhibited acid production by washed cells of Streptococci mutans from G, Gal, M, L or S (12-83% inhibition). S. mutans accumulated X5P intracellularly through activity of the phosphoenolpyruvate-xylitol phosphotransferase system (PEP-xylitol PTS) when they fermented these sugars in the presence of xylitol. However, in the presence of Fr, no inhibition of acid production was observed. In addition, the amounts of X5P during the fermentation of Fr were smaller than those of other sugars in spite of the presence of PEP-xylitol PTS activity. These results suggest that along with the intracellular accumulation of X5P, xylitol decreases the growth and acid production of mutans streptococci in the presence of various dietary sugars except Fr. PMID:14571117

Kakuta, Hatsue; Iwami, Yoshimichi; Mayanagi, Hideaki; Takahashi, Nobuhiro

2003-01-01

39

Linoleic Acid-Induced Growth Inhibition of Human Gastric Epithelial Adenocarcinoma AGS Cells is Associated with Down-Regulation of Prostaglandin E2 Synthesis and Telomerase Activity  

PubMed Central

Background: Linoleic acid is the most abundant polyunsaturated fatty acid in human nutrition and found in most vegetable oils and certain food products. In the present study, we investigated the effects of linoleic acid on the growth of human epithelial adenocarcinoma AGS cells. Methods: MTT assay, flow cytometry, RT-PCR and Western-blot analyses were used to investigate the effects and underlying mechanisms of linoleic acid on AGS cells. The effects of this compound were also tested on prostaglandin E2 (PGE2) production and telomerase activity. Results: Our data indicated that growth inhibition of AGS cells by linoleic acid treatment was associated with induction of apoptosis. Linoleic acid treatment decreased the expression levels of the cyclooxygenase (COX)-2 mRNA and protein without causing significant changes in the COX-1 levels, which was correlated with the inhibition of PGE2 synthesis. Linoleic acid treatment also decreased the expression of human telomerase reverse transcriptase (hTERT), a main determinant of the telomerase enzymatic activity, and activity of telomerase, with inhibiting the expression of c-myc in a concentration-dependent manner. Conclusions: Taken together, our results indicate that linoleic acid inhibits the production of PGE2 and activity of telomerase by suppressing COX-2 and hTERT expression. PMID:25337570

Choi, Yung Hyun

2014-01-01

40

Release of Cyclic Phosphatidic Acid from Gelatin-based Hydrogels Inhibit Colon Cancer Cell Growth and Migration  

PubMed Central

Microparticle and nanoparticle formulations are widely used to improve the bioavailability of low-solubility drugs and as vehicles for organ- and tissue-specific targeted drug delivery. We investigated the effect of a novel, controlled-release form of a bioactive lipid, cyclic phosphatidic acid (cPA), on human colon cancer cell line functions. We encapsulated cPA in gelatin-based hydrogels and examined its ability to inhibit the viability and migration of HT-29 and DLD-1 cells in vitro and the LPA-induced activity of the transcription factor peroxisome proliferator-activated receptor gamma (PPAR?). The hydrogel delivery system prolonged cPA release into the culture medium. Accordingly, cPA-hydrogel microspheres substantially inhibited LPA-induced PPAR? activity and cell growth and migration compared with that of cells cultured with cPA alone. Thus, hydrogel microspheres are a potential system for stable and efficient delivery of bioactive lipids such as cPA and may offer a new strategy for targeted colon cancer treatment. PMID:23008752

Tsukahara, Tamotsu; Murakami-Murofushi, Kimiko

2012-01-01

41

Lactate Acid Inhibition of Salmonella Typhimurium in Yogurt  

Microsoft Academic Search

We determined how lactic acid inhibits growth of Salmonella typhimurium in yogurt. This inhibition was demonstrated by microscopic examination not to be due to bacteriolysis. Neither growth nor meta- bolic activity could be initiated after cells were washed in phosphate buffer and exposed to 1.5% lactic acid for 1 h at 3 7°C, indicating that lactic acid inhibition is irreversible.

Howard E. Rubin; Thomas Nerad; Frizell Vaughan

1982-01-01

42

Organic iodine inhibits deoxyribonucleic acid synthesis and growth in FRTL-5 thyroid cells.  

PubMed

FRTL-5 thyroid epithelial cells in culture were used to study the possible inhibitory effects of iodine on thyroid growth. NaI exerted a dose-dependent, thyroid epithelial cell-specific inhibitory effect on [methyl-3H]thymidine incorporation into DNA, reduced the DNA content in the cell layer, and limited the increase in cell number mediated by TSH. The inhibitory effects of sodium iodide applied to growth stimulated by TSH-, cAMP-, and non-cAMP-dependent mechanisms and were prevented by 1-methylimidazole-2-thiol (methimazole) and 2-ethylthioisonicotinamide (ethionamide). The latter findings indicate that the inhibitory effects of NaI are mediated by some iodine-containing organic compound. The inhibitory effects of organic iodine on growth subsided 24-48 h after removal of excess NaI from the culture medium. In contrast, NaI had no effect on normal rat kidney fibroblast or thyroid fibroblast [methyl-3H]thymidine incorporation stimulated by epidermal growth factor or serum. These data demonstrate a specific inhibitory effect of organic iodine on thyroid epithelial cell growth. PMID:3383784

Becks, G P; Eggo, M C; Burrow, G N

1988-07-01

43

Gambogic acid induces growth inhibition and differentiation via upregulation of p21waf1/cip1 expression in acute myeloid leukemia cells.  

PubMed

Gambogic acid (GA) is the major active ingredient of gamboges, a brownish to orange resin product from Garcinia hanburyi tree in Southeast Asia. This compound exhibits anti-cancer effect on solid tumors. In this study, we investigated the effects of GA on the growth and differentiation of acute myeloid leukemia cells by growth-inhibition detection, morphological changes observation, nitroblue tetrazolium reduction, and the expression of the relative cell-surface differentiation markers. The results showed that GA could inhibit cell growth and promote differentiation in U937 and HL-60 cells. In addition, GA upregulated the expression of p21waf1/cip1 in the two cell lines. Finally, downregulating the p21waf1/cip1 expression with small interfering RNA partially blocked GA-induced cell growth inhibition and differentiation. These results of this study revealed that GA may be used as one of the investigational drugs for acute myeloid leukemia. PMID:24835506

Chen, Yan; Hui, Hui; Li, Zheng; Wang, Hong-Mei; You, Qi-Dong; Lu, Na

2014-10-01

44

Gallic acid inhibits gastric cancer cells metastasis and invasive growth via increased expression of RhoB, downregulation of AKT/small GTPase signals and inhibition of NF-?B activity  

SciTech Connect

Our previous study demonstrated the therapeutic potential of gallic acid (GA) for controlling tumor metastasis through its inhibitory effect on the motility of AGS cells. A noteworthy finding in our previous experiment was increased RhoB expression in GA-treated cells. The aim of this study was to evaluate the role of RhoB expression on the inhibitory effects of GA on AGS cells. By applying the transfection of RhoB siRNA into AGS cells and an animal model, we tested the effect of GA on inhibition of tumor growth and RhoB expression. The results confirmed that RhoB-siRNA transfection induced GA to inhibit AGS cells’ invasive growth involving blocking the AKT/small GTPase signals pathway and inhibition of NF-?B activity. Finally, we evaluated the effect of GA on AGS cell metastasis by colonization of tumor cells in nude mice. It showed GA inhibited tumor cells growth via the expression of RhoB. These data support the inhibitory effect of GA which was shown to inhibit gastric cancer cell metastasis and invasive growth via increased expression of RhoB, downregulation of AKT/small GTPase signals and inhibition of NF-?B activity. Thus, GA might be a potential agent in treating gastric cancer. Highlights: ? GA could downregulate AKT signal via increased expression of RhoB. ? GA inhibits metastasis in vitro in gastric carcinoma. ? GA inhibits tumor growth in nude mice model.

Ho, Hsieh-Hsun [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China)] [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China); Chang, Chi-Sen [Department of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China) [Department of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Division of Gastroenterology, Taichung Veterans General Hospital, Taichung 402, Taiwan (China); Ho, Wei-Chi [Division of Gastroenterology, Jen-Ai Hospital, Taichung 402, Taiwan (China)] [Division of Gastroenterology, Jen-Ai Hospital, Taichung 402, Taiwan (China); Liao, Sheng-You [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China)] [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China); Lin, Wea-Lung [Department of Pathology, School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China) [Department of Pathology, School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Pathology, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); Wang, Chau-Jong, E-mail: wcj@csmu.edu.tw [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China) [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Medical Research, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China)

2013-01-01

45

Ethylene-Induced Inhibition of Root Growth Requires Abscisic Acid Function in Rice (Oryza sativa L.) Seedlings  

PubMed Central

Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-localized membrane protein homologous to Arabidopsis thaliana (Arabidopsis) ABA4, which is responsible for a branch of ABA biosynthesis. MHZ4 mutation reduced ABA level, but promoted ethylene production. Ethylene induced MHZ4 expression and promoted ABA accumulation in roots. MHZ4 overexpression resulted in enhanced and reduced ethylene response in roots and coleoptiles, respectively. In root, MHZ4-dependent ABA pathway acts at or downstream of ethylene receptors and positively regulates root ethylene response. This ethylene-ABA interaction mode is different from that reported in Arabidopsis, where ethylene-mediated root inhibition is independent of ABA function. In coleoptile, MHZ4-dependent ABA pathway acts at or upstream of OsEIN2 to negatively regulate coleoptile ethylene response, possibly by affecting OsEIN2 expression. At mature stage, mhz4 mutation affects branching and adventitious root formation on stem nodes of higher positions, as well as yield-related traits. Together, our findings reveal a novel mode of interplay between ethylene and ABA in control of rice growth and development. PMID:25330236

He, Si-Jie; Lu, Xiang; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

2014-01-01

46

Ethylene-induced inhibition of root growth requires abscisic acid function in rice (Oryza sativa L.) seedlings.  

PubMed

Ethylene and abscisic acid (ABA) have a complicated interplay in many developmental processes. Their interaction in rice is largely unclear. Here, we characterized a rice ethylene-response mutant mhz4, which exhibited reduced ethylene-response in roots but enhanced ethylene-response in coleoptiles of etiolated seedlings. MHZ4 was identified through map-based cloning and encoded a chloroplast-localized membrane protein homologous to Arabidopsis thaliana (Arabidopsis) ABA4, which is responsible for a branch of ABA biosynthesis. MHZ4 mutation reduced ABA level, but promoted ethylene production. Ethylene induced MHZ4 expression and promoted ABA accumulation in roots. MHZ4 overexpression resulted in enhanced and reduced ethylene response in roots and coleoptiles, respectively. In root, MHZ4-dependent ABA pathway acts at or downstream of ethylene receptors and positively regulates root ethylene response. This ethylene-ABA interaction mode is different from that reported in Arabidopsis, where ethylene-mediated root inhibition is independent of ABA function. In coleoptile, MHZ4-dependent ABA pathway acts at or upstream of OsEIN2 to negatively regulate coleoptile ethylene response, possibly by affecting OsEIN2 expression. At mature stage, mhz4 mutation affects branching and adventitious root formation on stem nodes of higher positions, as well as yield-related traits. Together, our findings reveal a novel mode of interplay between ethylene and ABA in control of rice growth and development. PMID:25330236

Ma, Biao; Yin, Cui-Cui; He, Si-Jie; Lu, Xiang; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

2014-10-01

47

Locked nucleic acid modified DNA enzymes targeting early growth response-1 inhibit human vascular smooth muscle cell growth  

Microsoft Academic Search

Smooth muscle cell (SMC) proliferation and migration are key processes that occur in the pathogenesis of atherosclerosis and post-angio- plasty restenosis. In the present study, we designed locked nucleic acid (LNA)-modified DNAzymes targeting a specific region spanning the transla- tional start site of human EGR-1, an immediate-early gene, wherein two of the nucleotides in each of the 9+9 hybridizing arms

Roger G. Fahmy; Levon M. Khachigian

2004-01-01

48

Significance of the 2- O-sulfo group of l-iduronic acid residues in heparin on the growth inhibition of bovine pulmonary artery smooth muscle cells  

Microsoft Academic Search

Heparin inhibits the growth of several cell types in vitro, including bovine pulmonary artery smooth muscle cells (BPASMCs). To understand more about the heparin structure required for endogenous activity, chemically modified derivatives of native heparin and glycol-split heparin, namely, 2-O-desulfonated iduronic\\/glucuronic acid residues in heparin, and 2-O-desulfonated iduronic residues in glycol-split heparin were prepared. These were assayed for their antiproliferative

Hari G. Garg; Hicham Mrabat; Lunyin Yu; Craig Freeman; Boyangzi Li; Fuming Zhang; Robert J. Linhardt; Charles A. Hales

2008-01-01

49

High temperature stimulates acetic acid accumulation and enhances the growth inhibition and ethanol production by Saccharomyces cerevisiae under fermenting conditions.  

PubMed

Cellular responses of Saccharomyces cerevisiae to high temperatures of up to 42 °C during ethanol fermentation at a high glucose concentration (i.e., 100 g/L) were investigated. Increased temperature correlated with stimulated glucose uptake to produce not only the thermal protectant glycerol but also ethanol and acetic acid. Carbon flux into the tricarboxylic acid (TCA) cycle correlated positively with cultivation temperature. These results indicate that the increased demand for energy (in the form of ATP), most likely caused by multiple stressors, including heat, acetic acid, and ethanol, was matched by both the fermentation and respiration pathways. Notably, acetic acid production was substantially stimulated compared to that of other metabolites during growth at increased temperature. The acetic acid produced in addition to ethanol seemed to subsequently result in adverse effects, leading to increased production of reactive oxygen species. This, in turn, appeared to cause the specific growth rate, and glucose uptake rate reduced leading to a decrease of the specific ethanol production rate far before glucose depletion. These results suggest that adverse effects from heat, acetic acid, ethanol, and oxidative stressors are synergistic, resulting in a decrease of the specific growth rate and ethanol production rate and, hence, are major determinants of cell stability and ethanol fermentation performance of S. cerevisiae at high temperatures. The results are discussed in the context of possible applications. PMID:24706214

Woo, Ji-Min; Yang, Kyung-Mi; Kim, Sae-Um; Blank, Lars M; Park, Jin-Byung

2014-07-01

50

Defect of synthesis of very long-chain fatty acids confers resistance to growth inhibition by inositol phosphorylceramide synthase repression in yeast Saccharomyces cerevisiae.  

PubMed

Aureobasidin A (AbA) inhibits Aur1p, an enzyme catalysing the formation of inositol phosphorylceramide in the yeast Saccharomyces cerevisiae. AbA treatment results not only in reductions in complex sphingolipid levels but also in accumulation of ceramides, both of which are believed to lead to the growth defect caused by this inhibitor. We screened for mutants showing resistance to this drug, and found that a lack of ELO3, the gene involved in synthesis of very long-chain fatty acids, confers resistance to the inhibitor. The resistance as to growth inhibition by reduction in Aur1p activity was also confirmed by repression of AUR1 expression under the control of a tetracycline-regulatable promoter. Under the AUR1-repressive conditions, the ELO3 mutant showed reduction in the complex sphingolipid levels and the accumulation of ceramide, like wild-type cells. However, with repression of LCB1 encoding serine palmitoyltransferase or LIP1 encoding the ceramide synthase subunit, the ELO3 mutation did not confer resistance to growth inhibition induced by the impaired sphingolipid biosynthesis. Therefore, it is suggested that the ELO3 mutant shows resistance as to accumulation of ceramides, implying that the chain lengths of fatty acids in ceramide are a critical factor for the ceramide-induced growth defect under AUR1-repressive conditions. PMID:20709688

Tani, Motohiro; Kuge, Osamu

2010-11-01

51

[Ulcer therapy without acid inhibition].  

PubMed

The mechanism of action of ulcer drugs without acid inhibition appears to involve improvement of defensive factors of the gastroduodenal mucosa. The concept of ulcer healing without acid inhibition is attractive for theoretical reasons, because doubts have arisen about the safety of elevation of intragastric pH, especially in long-term treatment of peptic ulcer disease. Ulcer drugs that do not affect gastric acidity may therefore be preferred, provided they compare favorably to the best acid inhibitors available in terms of efficacy, adverse effects and other requirements. Among these drugs, sucralfate fulfills these criteria to a large extent. PMID:6547542

Koelz, H R

1984-05-19

52

???????????????????????????????????????????????????????????????? Escherichia coli ????????????????????????? ISOLATION AND SCREENING OF LACTIC ACID BACTERIA CAPABLE OF INHIBITING GROWTH OF SOME ESCHERICHIA COLI ISOLATED FROM SWINE  

Microsoft Academic Search

One hundred and forty-seven strains of lactic acid bacteria (LAB) were isolated from some soils, fermented foods, vegetables, fruits, milk and animal products. After cultivation in MRS broth at 37 ?C for 96 hours, each culture supernatant was evaluated its growth inhibitory activity by using a paper disc diffusion method against one strain of Escherichia coli O157:H7 and nine strains

Mongkhon Punyarat; Narumol Thongwai

53

Uric acid inhibits placental system A amino acid uptake.  

PubMed

Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasing uric acid concentrations in preeclamptic women is in part the result of uric acid-induced reductions in amino acid transport across the placenta. The objective of the current study was to examine the effects of uric acid on human placental System A amino acid transport using a primary placental villous explant model. Further, we examined the necessity of uric acid uptake and the role of redox signaling as a potential mechanism through which uric acid may attenuate System A activity. Placental uptake of a radiolabeled amino acid analogue, specific to the System A transporter, was reduced in a concentration-dependent fashion with increasing uric acid (0-7 mg/dL), corresponding to uric acid concentrations measured in healthy pregnant and preeclamptic women in the third trimester. Uric acid-induced reduction in System A activity was partially reversed by NADPH oxidase inhibition and completely eliminated by antioxidant treatment. This study demonstrates inhibition of placental System A amino acid transport with uric acid treatment, as a result of uric acid-induced stimulation of intracellular redox signaling cascades. These findings may be relevant to the increased frequency of fetal growth restriction observed in hyperuricemic preeclampsia. Additionally the results of this study, indicating a detrimental effect of hyperuricemia on amino acid transport in the placenta, at concentrations present in women with preeclampsia, also suggest a role for uric acid in the pathophysiology of preeclampsia. PMID:19058847

Bainbridge, S A; von Versen-Höynck, F; Roberts, J M

2009-02-01

54

Uric Acid Inhibits Placental System A Amino Acid Uptake?  

PubMed Central

Hyperuricemia, a common clinical characteristic of preeclamptic pregnancies, has historically been considered a marker of reduced renal function in preeclamptic women. More recently it has been suggested that uric acid may directly contribute to pathological cell signaling events involved in disease progression as well as maternal and fetal pregnancy outcomes including fetal growth restriction. We hypothesize that the increased frequency of restricted fetal growth seen in relation to increasing uric acid concentrations in preeclamptic women is in part the result of uric acid-induced reductions in amino acid transport across the placenta. The objective of the current study was to examine the effects of uric acid on human placental System A amino acid transport using a primary placental villous explant model. Further, we examined the necessity of uric acid uptake and the role of redox signaling as a potential mechanism through which uric acid may attenuate System A activity. Placental uptake of a radiolabeled amino acid analogue, specific to the System A transporter, was reduced in a concentration-dependent fashion with increasing uric acid (0?7 mg/dL), corresponding to uric acid concentrations measured in healthy pregnant and preeclamptic women in the third trimester. Uric acid-induced reduction in System A activity was partially reversed by NADPH oxidase inhibition and completely eliminated by antioxidant treatment. This study demonstrates inhibition of placental System A amino acid transport with uric acid treatment, as a result of uric acid-induced stimulation of intracellular redox signaling cascades. These findings may be relevant to the increased frequency of fetal growth restriction observed in hyperuricemic preeclampsia. Additionally the results of this study, indicating a detrimental effect of hyperuricemia on amino acid transport in the placenta, at concentrations present in women with preeclampsia, also suggest a role for uric acid in the pathophysiology of preeclampsia. PMID:19058847

Bainbridge, S.A.; von Versen-Hoynck, F.; Roberts, J.M.

2009-01-01

55

Ursolic Acid Inhibits Growth and Metastasis of Human Colorectal Cancer in an Orthotopic Nude Mouse Model by Targeting Multiple Cell Signaling Pathways: Chemosensitization with Capecitabine  

PubMed Central

Purpose Development of chemoresistance, poor prognosis, and metastasis often renders the current treatments for colorectal cancer (CRC) ineffective. Whether ursolic acid (UA), a component of numerous medicinal plants, either alone or in combination with capecitabine, can inhibit the growth and metastasis of human CRC was investigated. Experimental design The effect of UA on proliferation of colorectal cancer cell lines was examined by mitochondrial dye-uptake assay, apoptosis by esterase staining, NF-?B activation by DNA binding assay and protein expression by western blot. The effect of UA on the growth and chemosensitization was also examined in orthotopically-implanted CRC in nude mice. Results We found that UA inhibited the proliferation of different colon cancer cell lines. This is correlated with inhibition of constitutive NF-?B activation and downregulation of cell survival (Bcl-xL, Bcl-2, cFLIP, survivin), proliferative (Cyclin D1), and metastatic (MMP-9, VEGF, ICAM-1) proteins. When examined in an orthotopic nude-mice model, UA significantly inhibited tumor volume, ascites formation and distant organ metastasis, and this effect was enhanced with capecitabine. Immunohistochemistry of tumor tissue indicated that UA downregulated biomarkers of proliferation (Ki-67) and microvessel density (CD31). This effect was accompanied by suppression of NF-?B, STAT3, and ?-catenin. In addition, UA suppressed EGFR, and induced p53, and p21 expression. We also observed bioavailability of UA in the serum and tissue of animals. Conclusion Overall our results demonstrate that UA can inhibit the growth and metastasis of CRC and further enhance the therapeutic effects of capecitabine through suppression of multiple biomarkers linked to inflammation, proliferation, invasion, angiogenesis, and metastasis. PMID:22832932

Prasad, Sahdeo; Yadav, Vivek R.; Sung, Bokyung; Reuter, Simone; Kannappan, Ramaswamy; Deorukhkar, Amit; Diagaradjane, Parmeswaran; Wei, Caimiao; Baladandayuthapani, Veerabhadran; Krishnan, Sunil; Guha, Sushovan; Aggarwal, Bharat B.

2013-01-01

56

Short-Chain Fatty Acids Inhibit Growth Hormone and Prolactin Gene Transcription via cAMP/PKA/CREB Signaling Pathway in Dairy Cow Anterior Pituitary Cells  

PubMed Central

Short-chain fatty acids (SCFAs) play a key role in altering carbohydrate and lipid metabolism, influence endocrine pancreas activity, and as a precursor of ruminant milk fat. However, the effect and detailed mechanisms by which SCFAs mediate bovine growth hormone (GH) and prolactin (PRL) gene transcription remain unclear. In this study, we detected the effects of SCFAs (acetate, propionate, and butyrate) on the activity of the cAMP/PKA/CREB signaling pathway, GH, PRL, and Pit-1 gene transcription in dairy cow anterior pituitary cells (DCAPCs). The results showed that SCFAs decreased intracellular cAMP levels and a subsequent reduction in PKA activity. Inhibition of PKA activity decreased CREB phosphorylation, thereby inhibiting GH and PRL gene transcription. Furthermore, PTX blocked SCFAs- inhibited cAMP/PKA/CREB signaling pathway. These data showed that the inhibition of GH and PRL gene transcription induced by SCFAs is mediated by Gi activation and that propionate is more potent than acetate and butyrate in inhibiting GH and PRL gene transcription. In conclusion, this study identifies a biochemical mechanism for the regulation of SCFAs on bovine GH and PRL gene transcription in DCAPCs, which may serve as one of the factors that regulate pituitary function in accordance with dietary intake. PMID:24177567

Wang, Jian-Fa; Fu, Shou-Peng; Li, Su-Nan; Hu, Zhong-Ming; Xue, Wen-Jing; Li, Zhi-Qiang; Huang, Bing-Xu; Lv, Qing-Kang; Liu, Ju-Xiong; Wang, Wei

2013-01-01

57

The History of Acid Inhibition  

E-print Network

I review here the history of inhibition of gastric acid. References are limited to books and reviews in which detailed citations can be found. ANTACIDS In ancient times, acids were not understood in the modem chemical sense but merely as bitter sour liquids [1]. Some foods were thought acidic, and if the stomach had an ulcer, everything acrid was to be avoided and soothing remedies such as starch and milk used. Antacids neutralize, rather than inhibit, acid secretion but could not be rationally prescribed until acids were understood in the modern chemical sense. Hydrochloric acid has been known since the early fifteenth century, thought to be in the stomach by Paracelsus in the sixteenth and by Van Helmont in the seventeenth century, but it was not until 1823 that Prout definitively identified free hydrochloric acid in the gastric juice of man and animals and made quantitative measurements of its concentration. Antacids became widely used only this century, especially in association with Sippytype diets for ulcers [2]. As recently as the 1960s, orthodox gastroenterologists believed that gastric acidity was reduced by minimizing the amount of acid-stimulating foods such

J. H. Barona

1994-01-01

58

Alleviation of salt-induced photosynthesis and growth inhibition by salicylic acid involves glycinebetaine and ethylene in mungbean (Vigna radiata L.).  

PubMed

The influence of salicylic acid (SA) in alleviation of salt stress in mungbean (Vigna radiata L.) through modulation of glycinebetaine (GB) and ethylene was studied. SA application at 0.5 mM increased methionine (Met) and GB accumulation in plants concomitant with the suppression of ethylene formation by inhibiting 1-aminocyclopropane carboxylic acid synthase (ACS) activity more conspicuously under salt stress than no stress. The increased GB accumulation together with reduced ethylene under salt stress by SA application was associated with increased glutathione (GSH) content and lower oxidative stress. These positive effects on plant metabolism induced by SA application led to improved photosynthesis and growth under salt stress. These results suggest that SA induces GB accumulation through increased Met and suppresses ethylene formation under salt stress and enhances antioxidant system resulting in alleviation of adverse effects of salt stress on photosynthesis and growth. These effects of SA were substantiated by the findings that application of SA-analogue, 2, 6, dichloro-isonicotinic acid (INA) and ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG) resulted in similar effects on Met, GB, ethylene production, photosynthesis and growth under salt stress. Future studies on the interaction between SA, GB and ethylene could be exploited for adaptive responses of plants under salt stress. PMID:24727790

Khan, M Iqbal R; Asgher, M; Khan, Nafees A

2014-07-01

59

Methylseleninic acid elevates REDD1 and inhibits prostate cancer cell growth despite AKT activation and mTOR dysregulation in hypoxia  

PubMed Central

Methylseleninic acid (MSeA) is a monomethylated selenium metabolite theoretically derived from subsequent ?-lyase or transamination reactions of dietary Se-methylselenocysteine that has potent antitumor activity by inhibiting cell proliferation of several cancers. Our previous studies showed that MSeA promotes apoptosis in invasive prostate cancer cells in part by downregulating hypoxia-inducible factor HIF-1?. We have now extended these studies to evaluate the impact of MSeA on REDD1 (an mTOR inhibitor) in inducing cell death of invasive prostate cancer cells in hypoxia. In both PTEN+ and PTEN? prostate cancer cells we show that MSeA elevates REDD1 and phosphorylation of AKT along with p70S6K in hypoxia. Furthermore, REDD1 induction by MSeA is independent of AKT and the mTOR inhibition in prostate cancer cells causes partial resistance to MSeA-induced growth reduction in hypoxia. Our data suggest that MSeA induces REDD1 and inhibits prostate cancer cell growth in hypoxia despite activation of AKT and dysregulation of mTOR. MSeA elevates REDD1 and AKT to promote cell death in invasive prostate cancer cells in hypoxia. PMID:24515947

Sinha, Indu; Allen, Joshua E; Pinto, John T; Sinha, Raghu

2014-01-01

60

Boswellic acid inhibits growth and metastasis of human colorectal cancer in orthotopic mouse model by downregulating inflammatory, proliferative, invasive and angiogenic biomarkers.  

PubMed

Numerous cancer therapeutics were originally identified from natural products used in traditional medicine. One such agent is acetyl-11-keto-beta-boswellic acid (AKBA), derived from the gum resin of the Boswellia serrata known as Salai guggal or Indian frankincense. Traditionally, it has been used in Ayurvedic medicine to treat proinflammatory conditions. In this report, we hypothesized that AKBA can affect the growth and metastasis of colorectal cancer (CRC) in orthotopically implanted tumors in nude mice. We found that the oral administration of AKBA (50-200 mg/kg) dose-dependently inhibited the growth of CRC tumors in mice, resulting in decrease in tumor volumes than those seen in vehicle-treated mice without significant decreases in body weight. In addition, we observed that AKBA was highly effective in suppressing ascites and distant metastasis to the liver, lungs and spleen in orthotopically implanted tumors in nude mice. When examined for the mechanism, we found that markers of tumor proliferation index Ki-67 and the microvessel density cluster of differentiation (CD31) were significantly downregulated by AKBA treatment. We also found that AKBA significantly suppressed nuclear factor-?B (NF-?B) activation in the tumor tissue and expression of proinflammatory (cyclooxygenase-2), tumor survival (bcl-2, bcl-xL, inhibitor of apoptosis (IAP-1) and survivin), proliferative (cyclin D1), invasive (intercellular adhesion molecule 1 and matrix metalloproteinase-9) and angiogenic C-X-C (CXC) receptor 4 and vascular endothelial growth factor) biomarkers. When examined for serum and tissue levels of AKBA, a dose-dependent increase in the levels of the drug was detected, indicating its bioavailability. Thus, our findings suggest that this boswellic acid analog can inhibit the growth and metastasis of human CRC in vivo through downregulation of cancer-associated biomarkers. PMID:21702037

Yadav, Vivek R; Prasad, Sahdeo; Sung, Bokyung; Gelovani, Juri G; Guha, Sushovan; Krishnan, Sunil; Aggarwal, Bharat B

2012-05-01

61

Betulinic acid inhibits colon cancer cell and tumor growth and induces proteasome-dependent and -independent downregulation of specificity proteins (Sp) transcription factors  

PubMed Central

Background Betulinic acid (BA) inhibits growth of several cancer cell lines and tumors and the effects of BA have been attributed to its mitochondriotoxicity and inhibition of multiple pro-oncogenic factors. Previous studies show that BA induces proteasome-dependent degradation of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 in prostate cancer cells and this study focused on the mechanism of action of BA in colon cancer cells. Methods The effects of BA on colon cancer cell proliferation and apoptosis and tumor growth in vivo were determined using standardized assays. The effects of BA on Sp proteins and Sp-regulated gene products were analyzed by western blots, and real time PCR was used to determine microRNA-27a (miR-27a) and ZBTB10 mRNA expression. Results BA inhibited growth and induced apoptosis in RKO and SW480 colon cancer cells and inhibited tumor growth in athymic nude mice bearing RKO cells as xenograft. BA also decreased expression of Sp1, Sp3 and Sp4 transcription factors which are overexpressed in colon cancer cells and decreased levels of several Sp-regulated genes including survivin, vascular endothelial growth factor, p65 sub-unit of NF?B, epidermal growth factor receptor, cyclin D1, and pituitary tumor transforming gene-1. The mechanism of action of BA was dependent on cell context, since BA induced proteasome-dependent and proteasome-independent downregulation of Sp1, Sp3 and Sp4 in SW480 and RKO cells, respectively. In RKO cells, the mechanism of BA-induced repression of Sp1, Sp3 and Sp4 was due to induction of reactive oxygen species (ROS), ROS-mediated repression of microRNA-27a, and induction of the Sp repressor gene ZBTB10. Conclusions These results suggest that the anticancer activity of BA in colon cancer cells is due, in part, to downregulation of Sp1, Sp3 and Sp4 transcription factors; however, the mechanism of this response is cell context-dependent. PMID:21864401

2011-01-01

62

Acid precipitation and food quality: Inhibition of growth and survival in black ducks and mallards by dietary aluminum, calcium and phosphorus  

USGS Publications Warehouse

In areas impacted by acid precipitation, water chemistry of acidic ponds and streams often changes, resulting in increased mobilization of aluminum and decreased concentration of calcium carbonate. Aluminum binds with phosphorus and inhibits its uptake by organisms. Thus, invertebrate food organisms used by waterfowl may have inadequate Ca and P or elevated Al for normal growth and development. Acid rain and its effects may be one of the factors negatively impacting American black ducks (Anas rubripes) in eastern North America. One-day old mallards (A. platyrhynchos) and black ducks were placed on one of three Ca:P regimens: low:low (LL), normal:normal (NN), and low:high (LH) with each regimen divided further into three or four Al levels for 10 weeks. Forty-five % of the black ducks died on nine different diets whereas only 28% of the mallards died on three different diets. Mortality was significantly related to diet in both species. Growth rates for body weight, culmens, wings, and tarsi of both species on control diets exceeded those on many treatment diets but the differences were less apparent for mallards than for black ducks. Differences among treatments were due to both Ca:P and Al levels.

Sparling, D.W.

1990-01-01

63

Acid precipitation and food quality: inhibition of growth and survival in black ducks and mallards by dietary aluminum, calcium, and phosphorus.  

PubMed

In areas impacted by acid precipitation, water chemistry of acidic ponds and streams often changes, resulting in increased mobilization of aluminum and decreased concentration of calcium carbonate. Aluminum binds with phosphorus and inhibits its uptake by organisms. Thus, invertebrate food organisms used by waterfowl may have inadequate Ca and P or elevated Al for normal growth and development. Acid rain and its effects may be one of the factors negatively impacting American black ducks (Anas rubripes) in eastern North America. One-day old mallards (A. platyrhynchos) and black ducks were placed on one of three Ca:P regimens: low:low (LL), normal:normal (NN), and low:high (LH) with each regimen divided further into three or four Al levels for 10 weeks. Forty-five % of the black ducks died on nine different diets whereas only 28% of the mallards died on three different diets. Mortality was significantly related to diet in both species. Growth rates for body weight, culmens, wings, and tarsi of both species on control diets exceeded those on many treatment diets but the differences were less apparent for mallards than for black ducks. Differences among treatments were due to both Ca:P and Al levels. PMID:2353844

Sparling, D W

1990-01-01

64

Aromatic hydrocarbon receptor inhibits lysophosphatidic acid-induced vascular endothelial growth factor-A expression in PC-3 prostate cancer cells  

SciTech Connect

Highlights: •LPA-induced VEGF-A expression was regulated by HIF-1? and ARNT. •PI3K mediated LPA-induced VEGF-A expression. •AHR signaling inhibited LPA-induced VEGF-A expression in PC-3 cells. -- Abstract: Lysophosphatidic acid (LPA) is a lipid growth factor with multiple biological functions and has been shown to stimulate cancer cell secretion of vascular endothelial growth factor-A (VEGF-A) and trigger angiogenesis. Hypoxia-inducible factor-1 (HIF-1), a heterodimer consisting of HIF-1? and HIF-1? (also known as aromatic hydrocarbon receptor nuclear translocator (ARNT)) subunits, is an important regulator of angiogenesis in prostate cancer (PC) through the enhancement of VEGF-A expression. In this study, we first confirmed the ability of LPA to induce VEGF-A expression in PC-3 cells and then validated that LPA-induced VEGF-A expression was regulated by HIF-1? and ARNT through phosphatidylinositol 3-kinase activation. Aromatic hydrocarbon receptor (AHR), a receptor for dioxin-like compounds, functions as a transcription factor through dimerization with ARNT and was found to inhibit prostate carcinogenesis and vanadate-induced VEGF-A production. Since ARNT is a common dimerization partner of AHR and HIF-1?, we hypothesized that AHR might suppress LPA-induced VEGF-A expression in PC-3 cells by competing with HIF-1? for ARNT. Here we demonstrated that overexpression and ligand activation of AHR inhibited HIF-1-mediated VEGF-A induction by LPA treatment of PC-3 cells. In conclusion, our results suggested that AHR activation may inhibit LPA-induced VEGF-A expression in PC-3 cells by attenuating HIF-1? signaling, and subsequently, suppressing angiogenesis and metastasis of PC. These results suggested that AHR presents a potential therapeutic target for the prevention of PC metastasis.

Wu, Pei-Yi; Lin, Yueh-Chien; Lan, Shun-Yan [Institute of Zoology, National Taiwan University, Taipei, Taiwan (China)] [Institute of Zoology, National Taiwan University, Taipei, Taiwan (China); Huang, Yuan-Li [Department of Biotechnology, Asia University, Taichung, Taiwan (China)] [Department of Biotechnology, Asia University, Taichung, Taiwan (China); Lee, Hsinyu, E-mail: hsinyu@ntu.edu.tw [Institute of Zoology, National Taiwan University, Taipei, Taiwan (China) [Institute of Zoology, National Taiwan University, Taipei, Taiwan (China); Department of Life Science, National Taiwan University, Taipei, Taiwan (China)

2013-08-02

65

Caffeic Acid Derivatives Inhibit the Growth of Colon Cancer: Involvement of the PI3-K/Akt and AMPK Signaling Pathways  

PubMed Central

Background The aberrant regulation of phosphatidylinositide 3-kinases (PI3-K)/Akt, AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (m-TOR) signaling pathways in cancer has prompted significant interest in the suppression of these pathways to treat cancer. Caffeic acid (CA) has been reported to possess important anti-inflammatory actions. However, the molecular mechanisms by which CA derivatives including caffeic acid phenethyl ester (CAPE) and caffeic acid phenylpropyl ester (CAPPE), exert inhibitory effects on the proliferation of human colorectal cancer (CRC) cells have yet to be elucidated. Methodology/Principal Findings CAPE and CAPPE were evaluated for their ability to modulate these signaling pathways and suppress the proliferation of CRC cells both in vitro and in vivo. Anti-cancer effects of these CA derivatives were measured by using proliferation assays, cell cycle analysis, western blotting assay, reporter gene assay and immunohistochemical (IHC) staining assays both in vitro and in vivo. This study demonstrates that CAPE and CAPPE exhibit a dose-dependent inhibition of proliferation and survival of CRC cells through the induction of G0/G1 cell cycle arrest and augmentation of apoptotic pathways. Consumption of CAPE and CAPPE significantly inhibited the growth of colorectal tumors in a mouse xenograft model. The mechanisms of action included a modulation of PI3-K/Akt, AMPK and m-TOR signaling cascades both in vitro and in vivo. In conclusion, the results demonstrate novel anti-cancer mechanisms of CA derivatives against the growth of human CRC cells. Conclusions CA derivatives are potent anti-cancer agents that augment AMPK activation and promote apoptosis in human CRC cells. The structure of CA derivatives can be used for the rational design of novel inhibitors that target human CRC cells. PMID:24960186

Kuo, Yueh-Hsiung; Pai, Man-Hui; Chiu, Hsi-Lin; Rodriguez, Raymond L.; Tang, Feng-Yao

2014-01-01

66

Amplified lipid rafts of malignant cells constitute a target for inhibition of aberrantly active NFAT and melanoma tumor growth by the aminobisphosphonate zoledronic acid.  

PubMed

Nuclear factors of activated T cells (NFAT) are critical modulators of cancer cell growth and survival. However, the mechanisms of their oncogenic dysregulation and strategies for targeting in tumors remain elusive. Here, we report coupling of anti- apoptotic NFAT (NFAT2) activation to cholesterol-enriched lipid raft microdomains of malignant melanoma cells and interruption of this pathway by the aminobisphosphonate zoledronic acid (Zol). The pathway was indicated by capability of Zol to promote apoptosis and to retard in vivo outgrowth of tumorigenic melanoma cell variants through inhibition of permanently active NFAT2. NFAT2 inhibition resulted from disintegration of cholesterol-enriched rafts due to reduction of cellular cholesterol by Zol. Mechanistically, raft disruption abolished raft-localized robust store-operated Ca(2) (+) (SOC) entry, blocking constitutive activation of protein kinase B/Akt (PKB) and thereby reactivating the NFAT repressor glycogen synthase kinase 3? (GSK3?). Pro-apoptotic inactivation of NFAT2 also followed reactivation of GSK3? by direct inhibition of PKB or SOC, whereas GSK3? blockade prevented Zol-induced NFAT2 inhibition and cell death. The rescuing effect of GSK3? blockade was reproduced by recovery of entire SOC/PKB/GSK3? cascade after reconstitution of rafts by cholesterol replenishment of Zol-treated tumorigenic cells. Remarkably, these malignant cells displayed higher cholesterol and lipid raft content than non-tumorigenic cells, which expressed weak SOC, PKB and NFAT2 activities and resisted raft-ablating action of Zol. Together, the results underscore the functional relevance of amplified melanoma rafts for tumor-promoting NFAT2 signaling and reveal these distinctive microdomains as a target for in vitro and in vivo demise of tumorigenic cells through NFAT2 inhibition by the clinical agent Zol. PMID:25142972

Levin-Gromiko, Uliana; Koshelev, Valeria; Kushnir, Paz; Fedida-Metula, Shlomit; Voronov, Elena; Fishman, Daniel

2014-11-01

67

Antisense inhibition of gene expression and growth in gram-negative bacteria by cell-penetrating peptide conjugates of peptide nucleic acids targeted to rpoD gene.  

PubMed

Gram-negative bacteria (GNB) cause common and severe hospital- and community-acquired infections with a high incidence of multidrug resistance (MDR) and mortality. The emergence and spread of MDR-GNB strains limit therapeutic options and highlight the need to develop new therapeutic strategies. In this study, the peptide (RXR)(4)XB- and (KFF)(3)K-conjugated peptide nucleic acids (PPNAs) were developed to target rpoD, which encodes an RNA polymerase primary ?(70) that is thought to be essential for bacterial growth. Their antimicrobial activities were tested against different clinical isolates of MDR-GNB in vitro and in infection models. The (RXR)(4)XB- and (KFF)(3)K- conjugated PNAs were bactericidal against different strains of MDR-GNB in concentration-dependent and sequence-selective manner, whereas a PPNA with a scrambled base sequence had no effect on growth. Among tested PPNAs, (RXR)(4)XB conjugate PPNA06 showed more potent and broad spectrum inhibition in multidrug-resistant Escherichia coli, Salmonella enterica, Klebsiella pneumoniae, and Shigella flexneri in vitro and in vivo. The results were associated with suppression of rpoD mRNA and ?(70) expression, as well as ?(70) downstream regulated genes including ftsZ, mazF, prfB, rpoS, seqA, turfB and ygjD. The treatment of PPNA06 on mono- or multiple MDR-GBN infected human gastric mucosal epithelial cells demonstrated the complete inhibition on bacterial growth and no influence on morphology and growth of human cells. Also, PPNA06 did not show the induction of antibiotic resistance as compared with classical antibiotics in GNB. These findings firstly demonstrate that rpoD is potential target for developing antisense antibiotics, and indicate that peptide conjugates of anti-rpoD PNA are active against GNBs in vitro and in vivo. Our results offer a feasible strategy for treating MDR-GNB infections. PMID:22000398

Bai, Hui; You, Yu; Yan, Hua; Meng, Jingru; Xue, Xiaoyan; Hou, Zheng; Zhou, Ying; Ma, Xue; Sang, Guojun; Luo, Xiaoxing

2012-01-01

68

Application of DL-beta-aminobutyric acid (BABA) as a root drench to legumes inhibits the growth and reproduction of the pea aphid Acyrthosiphon pisum (Hemiptera: Aphididae).  

PubMed

DL-beta-aminobutyric acid (BABA) is a non-protein amino acid that is an effective inducer of resistance against a variety of plant pathogens. However, examples of BABA-induced resistance against insect herbivores have not been reported. We applied BABA as a soil drench to legumes and monitored its effects on the pea aphid Acyrthosiphon pisum (Harris). On tic bean (Vicia faba var. minor), BABA increased aphid mortality, caused a reduction in the mean relative growth rate of individual insects and lessened the intrinsic rate of population increase (rm). BABA also caused significant reductions in the growth rate of A. pisum on pea (Pisum sativa), broad bean (Vicia faba var. major), runner bean (Phaseolus coccineus), red clover (Trifolium pratense) and alfalfa (Medicago sativa). No direct toxic effects of BABA against A. pisum were found, and no phytotoxic effects that may have caused a reduction in aphid performance were detected. Possible mechanisms behind this BABA-induced inhibition of aphid performance are discussed. PMID:16197565

Hodge, S; Thompson, G A; Powell, G

2005-10-01

69

High Concentrations of L-Ascorbic Acid Specifically Inhibit the Growth of Human Leukemic Cells via Downregulation of HIF-1? Transcription  

PubMed Central

We examined the antileukemic effects of high concentrations of L-ascorbic acid (high AA) on human leukemic cells. In vitro, high AA markedly induced apoptosis in various leukemic cell lines by generating hydrogen peroxide (H2O2) but not in normal hematopoietic stem/progenitor cells. High AA significantly repressed leukemic cell proliferation as well as neoangiogenesis in immunodeficient mice. We then noted that in leukemic cells, HIF-1? transcription was strongly suppressed by high AA and correlated with the transcription of VEGF. Our data indicate that exposure to high AA markedly increased the intracellular AA content of leukemic cells and inhibited the nuclear translocation of NF-?B, which mediates expression of HIF-1?. We next generated K562 cells that overexpressed HIF-1? (K562-HIF1? cells) and assessed the mechanistic relationship between inhibition of HIF-1? transcription and the antileukemic effect of high AA. The ability of high AA to induce apoptosis was significantly lower in K562-HIF1? cells than in K562 cells in vitro. We found that expression of HIF-1?-regulated antiapoptotic proteins of the Bcl-2 family, such as Mcl-1, Bcl-xL, and Bcl-2, was significantly suppressed by high AA in K562 cells, but was sustained at higher levels in K562-HIF1? cells, regardless of high AA exposure. Moreover, repression of cell proliferation and neoangiogenesis by high AA was completely abrogated in mice receiving transplants of K562-HIF1? cells. These results indicate that, along with H2O2 generation, downregulation of HIF-1? transcription plays a crucial role in growth inhibition of human leukemic cells by high AA. PMID:23626851

Sawanobori, Masakazu; Uno, Tomoko; Matsuzawa, Hideyuki; Nakamura, Yoshihiko; Matsushita, Hiromichi; Ando, Kiyoshi

2013-01-01

70

Inhibition of Calcium Oxalate Crystal Growth in vitro by Uropontin: Another Member of the Aspartic Acid-Rich Protein Superfamily  

Microsoft Academic Search

The majority of human urinary stones are primarily composed of calcium salts. Although normal urine is frequently supersaturated with respect to calcium oxalate, most humans do not form stones. Inhibitors are among the multiple factors that may influence the complex process of urinary stone formation. We have isolated an inhibitor of calcium oxalate crystal growth from human urine by monoclonal

H. Shiraga; W. Min; W. J. Vandusen; M. D. Clayman; D. Miner; C. H. Terrell; J. R. Sherbotie; J. W. Foreman; C. Przysiecki; E. G. Neilson; J. R. Hoyer

1992-01-01

71

Inhibition of Ethylene Biosynthesis by Salicylic Acid  

PubMed Central

Salicylic acid inhibited ethylene formation from ACC in self-buffered (pH 3.8) pear (Pyrus communis) cell suspension cultures with a K1app of about 10 micromolar after 1 to 3 hours incubation. Inhibition appeared noncompetitive. Among 22 related phenolic compounds tested, only acetylsalicylic acid showed similar levels of inhibition. Inhibition by salicylic acid was inversely dependent on the pH of the culture medium and did not require a continuous external supply of salicylate. When compared to known inhibitors of the ethylene forming enzyme, cobalt, n-propyl gallate, and dinitrophenol, inhibition by salicylic acid most closely resembled that by dinitrophenol but salicylic acid did not produce the same degree of respiratory stimulation. Results are discussed in terms of other known effects of salicylic acid on plants, pH-dependency, and the possible influence of salicylic acid on electron transport. PMID:16666393

Leslie, Charles A.; Romani, Roger J.

1988-01-01

72

The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid inhibits growth of Erwinia amylovora and acts as a seed germination-arrest factor.  

PubMed

The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) shares biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by Pseudomonas fluorescens WH6. We found that culture filtrates of a P.?aeruginosa strain overproducing AMB weakly interfered with seed germination of the grassy weed Poa annua and strongly inhibited growth of Erwinia amylovora, the causal agent of the devastating orchard crop disease known as fire blight. AMB was active against a 4-formylaminooxyvinylglycine-resistant isolate of E.?amylovora, suggesting that the molecular targets of the two oxyvinylglycines in Erwinia do not, or not entirely, overlap. The AMB biosynthesis and transport genes were shown to be organized in two separate transcriptional units, ambA and ambBCDE, which were successfully expressed from IPTG-inducible tac promoters in the heterologous host P.?fluorescens CHA0. Engineered AMB production enabled this model biocontrol strain to become inhibitory against E.?amylovora and to weakly interfere with the germination of several graminaceous seeds. We conclude that AMB production requires no additional genes besides ambABCDE and we speculate that their expression in marketed fire blight biocontrol strains could potentially contribute to disease control. PMID:23757135

Lee, Xiaoyun; Azevedo, Mark D; Armstrong, Donald J; Banowetz, Gary M; Reimmann, Cornelia

2013-02-01

73

Lactobacillus acidophilus inhibits growth of Campylobacter pylori in vitro.  

PubMed Central

Campylobacter pylori has been implicated as a causative factor in acid-peptic disease. Lactobacillus acidophilus is known to inhibit the growth of pathogens in the human gastrointestinal tract. We recovered C. pylori from gastric antral biopsies of seven patients with acid-peptic disease; the isolates were then cultured in brucella broth. The effect of L. acidophilus (cultured in DeMan-Rogosa-Sharpe broth) on the growth of C. pylori was tested by a mixed culture technique. L. acidophilus inhibited the growth of all seven isolates of C. pylori in vitro. All these isolates were also inhibited by the L. acidophilus culture supernatant (brucella blood agar cup technique) obtained at or after 48 h of incubation. Inhibition of C. pylori growth was also observed with 1 and 3% lactic acid but not with 0.5 and 1% hydrogen peroxide, the L. acidophilus sonic extract, or a citrate-phosphate buffer (pH 4.0). We conclude that the inhibitory action of L. acidophilus on C. pylori is dependent on an extracellular secretory product, probably lactic acid. This inhibitory effect may be of therapeutic relevance in patients with C. pylori-positive acid-peptic disease. PMID:2511224

Bhatia, S J; Kochar, N; Abraham, P; Nair, N G; Mehta, A P

1989-01-01

74

Celecoxib and tauro-ursodeoxycholic acid co-treatment inhibits cell growth in familial adenomatous polyposis derived LT97 colon adenoma cells  

SciTech Connect

Chemoprevention would be a desirable strategy to avoid duodenectomy in patients with familial adenomatous polyposis (FAP) suffering from duodenal adenomatosis. We investigated the in vitro effects on cell proliferation, apoptosis, and COX-2 expression of the potential chemopreventives celecoxib and tauro-ursodeoxycholic acid (UDCA). HT-29 colon cancer cells and LT97 colorectal micro-adenoma cells derived from a patient with FAP, were exposed to low dose celecoxib and UDCA alone or in combination with tauro-cholic acid (CA) and tauro-chenodeoxycholic acid (CDCA), mimicking bile of FAP patients treated with UDCA. In HT-29 cells, co-treatment with low dose celecoxib and UDCA resulted in a decreased cell growth (14-17%, p < 0.01). A more pronounced decrease (23-27%, p < 0.01) was observed in LT97 cells. Cell growth of HT-29 cells exposed to 'artificial bile' enriched with UDCA, was decreased (p < 0.001), either in the absence or presence of celecoxib. In LT97 cells incubated with 'artificial bile' enriched with UDCA, cell growth was decreased only in the presence of celecoxib (p < 0.05). No clear evidence was found for involvement of proliferating cell nuclear antigen, caspase-3, or COX-2 in the cellular processes leading to the observed changes in cell growth. In conclusion, co-treatment with low dose celecoxib and UDCA has growth inhibitory effects on colorectal adenoma cells derived from a patient with FAP, and further research on this combination as promising chemopreventive strategy is desired. -- Highlights: Black-Right-Pointing-Pointer Celecoxib and UDCA acid co-treatment decreases cell growth in colon tumor cells. Black-Right-Pointing-Pointer UDCA enriched 'artificial bile' decreases LT-97 cell growth only in presence of celecoxib. Black-Right-Pointing-Pointer PCNA, caspase-3, nor COX-2 seem to be involved in the observed changes in cell growth.

Heumen, Bjorn W.H. van, E-mail: b.vanheumen@mdl.umcn.nl [Department of Gastroenterology and Hepatology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Roelofs, Hennie M.J.; Morsche, Rene H.M. te [Department of Gastroenterology and Hepatology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Marian, Brigitte [Institute of Cancer Research, Wien University, Vienna (Austria)] [Institute of Cancer Research, Wien University, Vienna (Austria); Nagengast, Fokko M.; Peters, Wilbert H.M. [Department of Gastroenterology and Hepatology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands)] [Department of Gastroenterology and Hepatology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands)

2012-04-15

75

High dose concentration administration of ascorbic acid inhibits tumor growth in BALB/C mice implanted with sarcoma 180 cancer cells via the restriction of angiogenesis  

PubMed Central

To test the carcinostatic effects of ascorbic acid, we challenged the mice of seven experimental groups with 1.7 × 10-4 mol high dose concentration ascorbic acid after intraperitoneal administrating them with sarcoma S-180 cells. The survival rate was increased by 20% in the group that received high dose concentration ascorbic acid, compared to the control. The highest survival rate was observed in the group in which 1.7 × 10-4 mol ascorbic acid had been continuously injected before and after the induction of cancer cells, rather than just after the induction of cancer cells. The expression of three angiogenesis-related genes was inhibited by 0.3 times in bFGF, 7 times in VEGF and 4 times in MMP2 of the groups with higher survival rates. Biopsy Results, gene expression studies, and wound healing analysis in vivo and in vitro suggested that the carcinostatic effect induced by high dose concentration ascorbic acid occurred through inhibition of angiogenesis. PMID:19671184

Yeom, Chang-Hwan; Lee, Gunsup; Park, Jin-Hee; Yu, Jaelim; Park, Seyeon; Yi, Sang-Yeop; Lee, Hye Ree; Hong, Young Seon; Yang, Joosung; Lee, Sukchan

2009-01-01

76

Heat-stress induced inhibition in growth and chlorosis in mungbean ( Phaseolus aureus Roxb.) is partly mitigated by ascorbic acid application and is related to reduction in oxidative stress  

Microsoft Academic Search

The rising temperatures (>35°C) are proving detrimental to summer-sown mungbean genotypes that experience inhibition of vegetative\\u000a and reproductive growth. In the present study, the mungbean plants growing hydroponically at varying temperatures of 30\\/20°C\\u000a (control), 35\\/25, 40\\/30, and 45\\/35°C (as day\\/night 12 h\\/12 h) with (50 ?M) or without ascorbic acid (ASC) were investigated\\u000a for effects on growth, membrane damage, chlorophyll loss, leaf water

Ramanpreet Kaur; Navneet Kaur; Kalpna Bhandhari; Neeru Kaushal; Kriti Gupta; T. S. Bains; Harsh Nayyar

77

Creatinine Inhibits D-Amino Acid Oxidase  

Microsoft Academic Search

Inhibition of D-amino acid oxidase (DAO) activity by various uremic retention products and guanidino compounds was investigated. Creatinine (CTN) was found to inhibit DAO at a similar concentration in the sera of uremic patients. The inhibition was competitive and the Ki value was 2.7 mM. Moreover, CTN was shown to interact with flavin adenine dinucleotide (FAD), a coenzyme of DAO.

Y. Nohara; J. Suzuki; T. Kinoshita; M. Watanabe

2002-01-01

78

Specific bile acids inhibit hepatic fatty acid uptake  

PubMed Central

Bile acids are known to play important roles as detergents in the absorption of hydrophobic nutrients and as signaling molecules in the regulation of metabolism. Here we tested the novel hypothesis that naturally occurring bile acids interfere with protein-mediated hepatic long chain free fatty acid (LCFA) uptake. To this end stable cell lines expressing fatty acid transporters as well as primary hepatocytes from mouse and human livers were incubated with primary and secondary bile acids to determine their effects on LCFA uptake rates. We identified ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) as the two most potent inhibitors of the liver-specific fatty acid transport protein 5 (FATP5). Both UDCA and DCA were able to inhibit LCFA uptake by primary hepatocytes in a FATP5-dependent manner. Subsequently, mice were treated with these secondary bile acids in vivo to assess their ability to inhibit diet-induced hepatic triglyceride accumulation. Administration of DCA in vivo via injection or as part of a high-fat diet significantly inhibited hepatic fatty acid uptake and reduced liver triglycerides by more than 50%. In summary, the data demonstrate a novel role for specific bile acids, and the secondary bile acid DCA in particular, in the regulation of hepatic LCFA uptake. The results illuminate a previously unappreciated means by which specific bile acids, such as UDCA and DCA, can impact hepatic triglyceride metabolism and may lead to novel approaches to combat obesity-associated fatty liver disease. PMID:22531947

Nie, Biao; Park, Hyo Min; Kazantzis, Melissa; Lin, Min; Henkin, Amy; Ng, Stephanie; Song, Sujin; Chen, Yuli; Tran, Heather; Lai, Robin; Her, Chris; Maher, Jacquelyn J.; Forman, Barry M.; Stahl, Andreas

2012-01-01

79

Tolfenamic acid decreases c-Met expression through Sp proteins degradation and inhibits lung cancer cells growth and tumor formation in orthotopic mice  

Microsoft Academic Search

Summary  The nonsteroidal anti-inflammatory drug (NSAID), tolfenamic acid (TA) is emerging as a new anti-cancer agent. TA induces the\\u000a degradation of specific Specificity protein (Sp) transcription factors, Sp1, Sp3 and Sp4 which are associated with tumor growth\\u000a and metastasis. In this study we have evaluated the effect of TA on lung cancer using both in vitro and in vivo models. TA

Jimmie Colon; Rafael Madero-Visbal; Santhi Konduri; Cheryl H. Baker; Luis J. Herrera; Stephen Safe; David Sheikh-Hamad; Ala Abudayyeh; Beatrice Alvarado; Maen Abdelrahim

2011-01-01

80

Inhibition of Growth of Tetrahymena piriformis by Certain Steroids  

Microsoft Academic Search

SUMMARY: The growth of Tetrahyrnena piriformis W is inhibited by several steroids of mammalian origin. The degree of inhibition is related to the molecular configuration. All of the effective growth inhibitors were of the carbon-21 or pregnane series. Hydroxyl substitution at carbon-1 1 enhanced inhibition, while hydroxyl sub- stitution at carbon-17 lowered the potency of inhibition. The inhibition of growth

R. L. CONNER

1959-01-01

81

Theobromine Inhibits Uric Acid Crystallization. A Potential Application in the Treatment of Uric Acid Nephrolithiasis  

PubMed Central

Purpose To assess the capacity of methylxanthines (caffeine, theophylline, theobromine and paraxanthine) to inhibit uric acid crystallization, and to evaluate their potential application in the treatment of uric acid nephrolithiasis. Materials and Methods The ability of methylxathines to inhibit uric acid nucleation was assayed turbidimetrically. Crystal morphology and its modification due to the effect of theobromine were evaluated by scanning electron microscopy (SEM). The ability of theobromine to inhibit uric acid crystal growth on calculi fragments resulting from extracorporeal shock wave lithotripsy (ESWL) was evaluated using a flow system. Results The turbidimetric assay showed that among the studied methylxanthines, theobromine could markedly inhibit uric acid nucleation. SEM images showed that the presence of theobromine resulted in thinner uric acid crystals. Furthermore, in a flow system theobromine blocked the regrowth of post-ESWL uric acid calculi fragments. Conclusions Theobromine, a natural dimethylxanthine present in high amounts in cocoa, acts as an inhibitor of nucleation and crystal growth of uric acid. Therefore, theobromine may be clinically useful in the treatment of uric acid nephrolithiasis. PMID:25333633

Grases, Felix; Rodriguez, Adrian; Costa-Bauza, Antonia

2014-01-01

82

Inhibition of myeloperoxidase by salicylhydroxamic acid.  

PubMed Central

Salicylhydroxamic acid inhibited the luminol-dependent chemiluminescence of human neutrophils stimulated by phorbol 12-myristate 13-acetate or the chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe). This compound had no inhibitory effect on the kinetics of O2.- generation or O2 uptake during the respiratory burst, but inhibited both the peroxidative activity of purified myeloperoxidase and the chemiluminescence generated by a cell-free myeloperoxidase/H2O2 system. The concentration of salicylhydroxamic acid necessary for complete inhibition of myeloperoxidase activity was 30-50 microM (I50 values of 3-5 microM) compared with the non-specific inhibitor NaN3, which exhibited maximal inhibition at 100-200 microM (I50 values of 30-50 microM). Whereas taurine inhibited the luminol chemiluminescence of an H2O2/HOC1 system by HOC1 scavenging, this compound had little effect on myeloperoxidase/H2O2-dependent luminol chemiluminescence; in contrast, 10 microM-salicylhydroxamic acid did not quench HOC1 significantly but greatly diminished myeloperoxidase/H2O2-dependent luminol chemiluminescence, indicating that its effects on myeloperoxidase chemiluminescence were largely due to peroxidase inhibition rather than non-specific HOC1 scavenging. Salicylhydroxamic acid prevented the formation of myeloperoxidase Compound II, but only at low H2O2 concentrations, suggesting that it may compete for the H2O2-binding site on the enzyme. These data suggest that salicylhydroxamic acid may be used as a potent inhibitor to delineate the function of myeloperoxidase in neutrophil-mediated inflammatory events. PMID:2543361

Davies, B; Edwards, S W

1989-01-01

83

Luteolin, ellagic acid and punicic acid are natural products that inhibit prostate cancer metastasis.  

PubMed

Prostate cancer (PCa) is the second cause of cancer deaths in men in the USA. When the cancer recurs, early stages can be controlled with hormone ablation therapy to delay the rate of cancer progression but, over time, the cancer overcomes its hormone dependence, becomes highly aggressive and metastasizes. Clinical trials have shown that pomegranate juice (PJ) inhibits PCa progression. We have previously shown that the PJ components luteolin (L), ellagic acid (E) and punicic acid (P) together inhibit growth of hormone-dependent and -independent PCa cells and inhibit their migration and chemotaxis towards CXCL12, a chemokine that is important in PCa metastasis. On the basis of these findings, we hypothesized that L+E+P inhibit PCa metastasis in vivo. To test this possibility, we used a severe combined immunodeficiency mouse model in which luciferase-expressing human PCa cells were injected subcutaneously near the prostate. Tumor progression was monitored with bioluminescence imaging weekly. We found that L+E+P inhibits PC-3M-luc primary tumor growth, inhibits the CXCL12/CXCR4 axis for metastasis and none of the tumors metastasized. In addition, L+E+P significantly inhibits growth and metastasis of highly invasive Pten (-/-) ;K-ras (G12D) prostate tumors. Furthermore, L+E+P inhibits angiogenesis in vivo, prevents human endothelial cell (EC) tube formation in culture and disrupts preformed EC tubes, indicating inhibition of EC adhesion to each other. L+E+P also inhibits the angiogenic factors interleukin-8 and vascular endothelial growth factor as well as their induced signaling pathways in ECs. In conclusion, these results show that L+E+P inhibits PCa progression and metastasis. PMID:25023990

Wang, Lei; Li, Wenfang; Lin, Muqing; Garcia, Monika; Mulholland, David; Lilly, Michael; Martins-Green, Manuela

2014-10-01

84

Mechanism of inhibited growth of Bacillus pumilus by Propionibacterium freudenreichii subsp. shermanii.  

PubMed

Physiological studies were conducted in an attempt to elucidate the mechanism of inhibition of Bacillus pumilus by Propionibacterium freudenreichii subsp. shermanii. Inhibition of B. pumilus by P. shermanii occurred in media supplemented with 1% glucose, indicating that glucose utilization by the latter bacterium was not responsible for growth inhibition of the former bacterium. The medium pH in which P. shermanii inhibited the growth of B. pumilus was 4.3. Propionic acid was positively identified in the culture medium in which B. pumilus was inhibited by P. shermanii. The presence of propionic acid and a low medium pH may account for the inhibition of B. pumilus by P. shermanii. Sodium lactate concentrations of 0.8-1.0% were essential for the continuous growth of and propionic acid production by P. shermanii. Thus, use of P. shermanii to inhibit B. pumilus in foods would likely require a lactate source. PMID:8060789

Marshall, D L; Odame-Darkwah, J K

1994-04-01

85

Phytic Acid Inhibits Lipid Peroxidation In Vitro  

PubMed Central

Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100??M and 500??M effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10–20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100??M and 500??M significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100??M and 500??M) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products. PMID:24260736

Weglarz, Ludmila; Dzierzewicz, Zofia

2013-01-01

86

Inhibition of the activity of mushroom tyrosinase by alkylbenzoic acids  

Microsoft Academic Search

The inhibition kinetics of alkylbenzoic acids on the diphenolase activity of mushroom tyrosinase have been investigated. The results show that the alkylbenzoic acids assayed can lead to reversible inhibition of the enzyme; furthermore, o-toluic acid and m-toluic acid are mixed-type inhibitors and p-alkylbenzoic acids are uncompetitive inhibitors. The inhibition constants have been determined. For these p-alkylbenzoic acids, the inhibition strength

Xiao-Hong Huang; Qing-Xi Chen; Qin Wang; Kang-Kang Song; Jun Wang; Li Sha; Xiong Guan

2006-01-01

87

Mechanism of Action of Nalidixic Acid on Escherichia coli II. Inhibition of Deoxyribonucleic Acid Synthesis  

PubMed Central

Goss, William A. (Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William H. Deitz, and Thomas M. Cook. Mechanism of action of nalidixic acid on Escherichia coli. II. Inhibition of deoxyribonucleic acid synthesis. J. Bacteriol. 89:1068–1074. 1965.—Nalidixic acid was shown to inhibit specifically the synthesis of deoxyribonucleic acid (DNA) in Escherichia coli. Slight effects on protein and ribonucleic acid (RNA) synthesis were observed only at higher levels of drug or after prolonged incubation. The inhibition of DNA synthesis in E. coli 15TAU, as measured by incorporation of C14-labeled thymine, was observed after exposure to nalidixic acid for 10 min. Inhibition of the incorporation of C14-labeled uracil into RNA and C14-labeled l-arginine into protein (21 and 28% inhibition, respectively) was observed only after 60 min of exposure. When cultures of E. coli 15TAU were exposed to 3.0 ?g/ml of nalidixic acid (slightly greater than the minimal growth inhibitory concentration), the incorporation of C14-labeled thymidine was inhibited 30 to 40% after 90 min. Nalidixic acid at 10 ?g/ml, a lethal concentration, inhibited thymidine incorporation 72% during this period. Nalidixic acid at 1.0 ?g/ml had no apparent effect on the incorporation of C14-labeled adenine or C14-labeled uracil into RNA of cultures of E. coli 198, a wild-type strain. However, incorporation of both bases into DNA was strongly inhibited after 60 min of exposure (66 and 69%, respectively). Nalidixic acid inhibited DNA replication during a single round of synthesis. In contrast with “thymineless death,” nalidixic acid was not lethal to E. coli 15TAU during restricted RNA and protein synthesis (i.e., in a medium containing thymine but lacking arginine and uracil). We have shown also that this chemotherapeutic agent has little effect on the synthesis of protein or RNA required to initiate DNA replication. After 75 min of inhibition, the capacity of E. coli 15TAU to synthesize DNA in a medium containing thymine, arginine, and uracil may be restored by a simple filtration and washing process, indicating that the drug is not firmly bound. These studies leave little doubt that a primary action of nalidixic acid is the inhibition of the synthesis of DNA in E. coli. PMID:14276097

Goss, William A.; Deitz, William H.; Cook, Thomas M.

1965-01-01

88

Boric acid inhibits human prostate cancer cell proliferation  

Microsoft Academic Search

The role of boron in biology includes coordinated regulation of gene expression in mixed bacterial populations and the growth and proliferation of higher plants and lower animals. Here we report that boric acid, the dominant form of boron in plasma, inhibits the proliferation of prostate cancer cell lines, DU-145 and LNCaP, in a dose-dependent manner. Non-tumorigenic prostate cell lines, PWR-1E

Wade T. Barranco; Curtis D. Eckhert

2004-01-01

89

Bacterial contact-dependent growth inhibition (CDI)  

PubMed Central

Bacteria cooperate to form multicellular communities and compete against one another for environmental resources. Here, we review recent advances in our understanding of bacterial competition mediated by contact-dependent growth inhibition (CDI) systems. Different CDI+ bacteria deploy a variety of toxins to inhibit neighboring cells and protect themselves from autoinhibition by producing specific immunity proteins. The genes encoding CDI toxin–immunity pairs appear to be exchanged between cdi loci and are often associated with other toxin-delivery systems in diverse bacteria. CDI also appears to facilitate cooperative behavior between kin, suggesting that these systems may have other roles beyond competition. PMID:23473845

Ruhe, Zachary C.; Low, David A.; Hayes, Christopher S.

2013-01-01

90

Mechanisms of proteoglycan inhibition of hydroxyapatite growth  

Microsoft Academic Search

Summary  Purified bovine nasal cartilage proteoglycans (aggregate and subunit containing fractions) and to a lesser degree, chondroitin\\u000a 4-sulfate of physiological size, retard seeded hydroxyapatite (HA) growthin vitro. The large hydrodynamic size and high charge density of these macromolecules are believed to be associated with the ability\\u000a of proteoglycans to inhibit HA formation and growth. We now demonstrate the involvement of the

Chun-Chang Chen; Adele L. Boskey

1985-01-01

91

Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells  

PubMed Central

Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase) has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-?-boswellic acids (AKBA), a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health. PMID:19951413

2009-01-01

92

Sulindac sulfide and caffeic acid phenethyl ester suppress the motility of lung adenocarcinoma cells promoted by transforming growth factor-beta through Akt inhibition.  

PubMed

Cell migration is essential for invasive and metastatic phenotypes of cancer cells. Potential chemopreventive agents of cancer-sulindac sulfide, caffeic acid phenethyl ester (CAPE), curcumin, and (+)-catechin-have been reported to interfere with several types of intracellular signaling. In this study, we examined the effects of these agents on transforming growth factor-beta(TGF-beta)-induced motility and Akt phosphorylation in A549 cells. Judged by gold particle phagokinesis assay, sulindac sulfide, CAPE, and curcumin suppressed the motility of A549 cells promoted by TGF-beta. LY294002, a specific inhibitor of phosphatidylinositol 3-kinase(PI3K)/Akt signaling, also suppressed TGF-beta-induced motility and Akt phosphorylation. Sulindac sulfide and CAPE, but not curcumin, suppressed TGF-beta-induced Akt phosphorylation. We conclude that sulindac sulfide and CAPE suppress the motility promoted by TGF-beta in lung adenocarcinoma cells through the suppression of Akt. Our observations raise the possibility that these agents, except for (+)-catechin, can be applied not only as chemopreventive agents but also as anti-metastatic therapy. PMID:14691717

Shigeoka, Yasushi; Igishi, Tadashi; Matsumoto, Shingo; Nakanishi, Hirofumi; Kodani, Masahiro; Yasuda, Kazuhito; Hitsuda, Yutaka; Shimizu, Eiji

2004-03-01

93

Regulation of intestinal mucosal growth by amino acids.  

PubMed

Amino acids, especially glutamine (GLN) have been known for many years to stimulate the growth of small intestinal mucosa. Polyamines are also required for optimal mucosal growth, and the inhibition of ornithine decarboxylase (ODC), the first rate-limiting enzyme in polyamine synthesis, blocks growth. Certain amino acids, primarily asparagine (ASN) and GLN stimulate ODC activity in a solution of physiological salts. More importantly, their presence is also required before growth factors and hormones such as epidermal growth factor and insulin are able to increase ODC activity. ODC activity is inhibited by antizyme-1 (AZ) whose synthesis is stimulated by polyamines, thus, providing a negative feedback regulation of the enzyme. In the absence of amino acids mammalian target of rapamycin complex 1 (mTORC1) is inhibited, whereas, mTORC2 is stimulated leading to the inhibition of global protein synthesis but increasing the synthesis of AZ via a cap-independent mechanism. These data, therefore, explain why ASN or GLN is essential for the activation of ODC. Interestingly, in a number of papers, AZ has been shown to inhibit cell proliferation, stimulate apoptosis, or increase autophagy. Each of these activities results in decreased cellular growth. AZ binds to and accelerates the degradation of ODC and other proteins shown to regulate proliferation and cell death, such as Aurora-A, Cyclin D1, and Smad1. The correlation between the stimulation of ODC activity and the absence of AZ as influenced by amino acids is high. Not only do amino acids such as ASN and GLN stimulate ODC while inhibiting AZ synthesis, but also amino acids such as lysine, valine, and ornithine, which inhibit ODC activity, increase the synthesis of AZ. The question remaining to be answered is whether AZ inhibits growth directly or whether it acts by decreasing the availability of polyamines to the dividing cells. In either case, evidence strongly suggests that the regulation of AZ synthesis is the mechanism through which amino acids influence the growth of intestinal mucosa. This brief article reviews the experiments leading to the information presented above. We also present evidence from the literature that AZ acts directly to inhibit cell proliferation and increase the rate of apoptosis. Finally, we discuss future experiments that will determine the role of AZ in the regulation of intestinal mucosal growth by amino acids. PMID:23904095

Ray, Ramesh M; Johnson, Leonard R

2014-03-01

94

Activated microglia inhibit axonal growth through RGMa.  

PubMed

By causing damage to neural networks, spinal cord injuries (SCI) often result in severe motor and sensory dysfunction. Functional recovery requires axonal regrowth and regeneration of neural network, processes that are quite limited in the adult central nervous system (CNS). Previous work has shown that SCI lesions contain an accumulation of activated microglia, which can have multiple pathophysiological influences. Here, we show that activated microglia inhibit axonal growth via repulsive guidance molecule a (RGMa). We found that microglia activated by lipopolysaccharide (LPS) inhibited neurite outgrowth and induced growth cone collapse of cortical neurons in vitro--a pattern that was only observed when there was direct contact between microglia and neurons. After microglia were activated by LPS, they increased expression of RGMa; however, treatment with RGMa-neutralizing antibodies or transfection of RGMa siRNA attenuated the inhibitory effects of microglia on axonal outgrowth. Furthermore, minocycline, an inhibitor of microglial activation, attenuated the effects of microglia and RGMa expression. Finally, we examined whether these in vitro patterns could also be observed in vivo. Indeed, in a mouse SCI model, minocycline treatment reduced the accumulation of microglia and decreased RGMa expression after SCI, leading to reduced dieback in injured corticospinal tracts. These results suggest that activated microglia play a major role in inhibiting axon regeneration via RGMa in the injured CNS. PMID:21957482

Kitayama, Mari; Ueno, Masaki; Itakura, Toru; Yamashita, Toshihide

2011-01-01

95

Growth inhibition of thermotolerant yeast, Kluyveromyces marxianus, in hydrolysates from cassava pulp.  

PubMed

In this study, we report the inhibition of Kluyveromyces marxianus TISTR5925 growth and ethanol fermentation in the presence of furan derivatives and weak acids (acetic acid and lactic acid) at high temperatures. Cassava pulp, obtained as the waste from starch processing, was collected from 14 starch factories located in several provinces of Thailand. At a high temperature (42 °C), the cassava pulp hydrolysate from some starch factories strongly inhibited growth and ethanol production of both K. marxianus (strain TISTR5925) and Saccharomyces cerevisiae (strain K3). HPLC detected high levels of lactic acid and acetic acid in the hydrolysates, suggesting that these weak acids impaired the growth of K. marxianus at high temperature. We isolated Trp-requiring mutants that had reduced tolerance to acetic acid compared to the wild-type. This sensitivity to acetic acid was suppressed by supplementation of the medium with tryptophan. PMID:24781978

Rugthaworn, Prapassorn; Murata, Yoshinori; Machida, Masashi; Apiwatanapiwat, Waraporn; Hirooka, Akiko; Thanapase, Warunee; Dangjarean, Hatairat; Ushiwaka, Satoru; Morimitsu, Kozo; Kosugi, Akihiko; Arai, Takamitsu; Vaithanomsat, Pilanee

2014-07-01

96

SPLUNC1 is associated with nasopharyngeal carcinoma prognosis and plays an important role in all-trans-retinoic acid-induced growth inhibition and differentiation in nasopharyngeal cancer cells.  

PubMed

Human SPLUNC1 can suppress nasopharyngeal carcinoma (NPC) tumor formation; however, the correlation between SPLUNC1expression and NPC patient prognosis has not been reported. In the present study, we used a large-scale sample of 1015 tissue cores to detect SPLUNC1 expression and its association with patient prognosis. SPLUNC1 expression was reduced in NPC samples compared to nontumor nasopharyngeal epithelium tissues. Positive expression of SPLUNC1 in NPC predicted a better prognosis (disease-free survival, P = 0.034; overall survival, P = 0.048). Cox's proportional hazards model revealed that SPLUNC1 could be a significant prognostic factor affecting disease-free survival (P = 0.027). A cDNA micro-array analyzed by significant analysis of micro-array (SAM) and ingenuity pathway analysis (IPA) revealed that an indirect interaction existed between SPLUNC1 and retinoic acid (RA) in the cancer regulatory network. To further investigate the molecular mechanisms involved, we utilized several bioinformatics tools and identified 12 retinoid X receptors heterodimer binding sites in the promoter region of the SPLUNC1 gene. The transcriptional activity of the SPLUNC1 promoter was up-regulated significantly by all-trans-retinoic acid (ATRA). SPLUNC1 and retinoic acid receptor expression were induced significantly by ATRA, and removal of ATRA led to a progressive loss of SPLUNC1 and retinoic acid receptor expression. ATRA inhibited proliferation and induced the differentiation of NPC cells. Interestingly, over-expression of SPLUNC1 sensitized NPC cells to ATRA, whereas knockdown of SPLUNC1 in HNE1 cells increased cell viability. Under SPLUNC1 knockdown conditions, differentiation was reversed by ATRA treatment. We concluded that SPLUNC1 could potentially predict prognosis for NPC patients and play an important role in ATRA-induced growth inhibition and differentiation in NPC cells. PMID:25161098

Zhang, Wenling; Zeng, Zhaoyang; Wei, Fang; Chen, Pan; Schmitt, David C; Fan, Songqing; Guo, Xiaofang; Liang, Fang; Shi, Lei; Liu, Zixin; Zhang, Zuping; Xiang, Bo; Zhou, Ming; Huang, Donghai; Tang, Ke; Li, Xiaoling; Xiong, Wei; Tan, Ming; Li, Guiyuan; Li, Xiayu

2014-11-01

97

Inhibition of Lipid Synthesis of Bacteria, Yeast and Animal Cells by Anacardic Acids, Glycerol3-phosphate Dehydrogenase Inhibitors from Ginkgo  

Microsoft Academic Search

The effects of anacardic acids (Ana), glycerol-3-phosphate dehydrogenase (GPDH) inhibitors from ginkgo, on growth and lipid synthesis ofBacillus subtilis, Lipomyces starkeyiand 3T3-L1 cells were examined. Ana inhibited growth ofB. subtilis, and the inhibition was reversed by phosphatidic acid or monoacylglycerol. Ana-a (100 ?g\\/mL) inhibited lipid accumulation inL. starkeyi, but not growth, when it was added after 40 h of incubation.

Masatsune Murata; Junko Irie; Seiichi Homma

1997-01-01

98

Equine platelets inhibit E. coli growth and can be activated by bacterial lipopolysaccharide and lipoteichoic acid although superoxide anion production does not occur and platelet activation is not associated with enhanced production by neutrophils.  

PubMed

Activated platelets can contribute to host defense through release of products with bactericidal actions such as antimicrobial peptides and reactive oxygen species (ROS), as well as by forming heterotypic aggregates with neutrophils and enhancing their antimicrobial properties. Whilst release of vasoactive mediators from equine platelets in response to stimuli including bacterial lipopolysaccharide (LPS) has been documented, neither ROS production, nor the effects of activated platelets on equine neutrophil ROS production, have been reported. This study first sought evidence that activated equine platelets inhibit bacterial growth. Platelet superoxide production in response to stimuli including Escherichia coli-derived LPS and lipoteichoic acid (LTA) from Staphylococcus aureus was then determined. The ability of LPS and LTA to up-regulate platelet P-selectin expression and induce platelet-neutrophil aggregate formation was investigated and the effect of co-incubating activated platelets with neutrophils on superoxide production measured. Growth of E. coli was inhibited in a time-dependent manner, and to a similar extent, by addition of platelet rich plasma (PRP) or platelet poor plasma (PPP) obtained by centrifugation of PRP. Activation of platelets in PRP by addition of thrombin led to a significant increase in the inhibitory action between 0.5 and 2h. Although phorbol myristate acetate (PMA) caused superoxide production by equine platelets in a protein kinase C-dependent manner, thrombin, platelet activating factor (PAF), LPS, LTA and formyl-methionyl-leucyl phenylalanine (FMLP) were without effect. LPS and LTA did induce platelet activation, measured as an increase in P-selectin expression (% positive cells: 17±3 (un-stimulated); 63±6 (1?g/ml LPS); 64±6 (1?g/ml LTA); n=5) but not platelet superoxide production or heterotypic aggregate formation. Co-incubation of activated platelets with neutrophils did not increase neutrophil superoxide production. This study has demonstrated for the first time that when activated, equine platelets, like those of other species, are capable of releasing ROS that could assist in bacterial killing. However, the findings suggest that neither superoxide production by platelets nor enhancement of production by neutrophils is likely to play a significant role. Nevertheless, as has been reported in man, equine PPP and PRP did inhibit E. coli growth in vitro, and addition of thrombin significantly increased the inhibitory effect of PRP. This suggests that products released from activated platelets could contribute to antimicrobial activity in the horse. The factors in equine plasma and released by activated platelets that are responsible for inhibiting bacterial growth have yet to be determined. PMID:23332730

Aktan, I; Dunkel, B; Cunningham, F M

2013-04-15

99

Osteoclast inhibition impairs chondrosarcoma growth and bone destruction.  

PubMed

Because Chondrosarcoma is resistant to available chemotherapy and radiation regimens, wide resection is the mainstay in treatment, which frequently results in high morbidity and which may not prevent local recurrence. There is a clear need for improved adjuvant treatment of this malignancy. We have observed the presence of osteoclasts in the microenvironment of chondrosarcoma in human pathological specimens. We utilized the Swarm rat chondrosarcoma (SRC) model to test the hypothesis that osteoclasts affect chondrosarcoma pathogenesis. We implanted SRC tumors in tibia of Sprague-Dawley rats and analyzed bone histologically and radiographically for bone destruction and tumor growth. At three weeks, tumors invaded local bone causing cortical disruption and trabecular resorption. Bone destruction was accompanied by increased osteoclast number and resorbed bone surface. Treatment of rats with the zoledronic acid prevented cortical destruction, inhibited trabecular resorption, and resulted in decreased tumor volume in bone. To confirm that inhibition of osteoclasts per se, and not off-target effects of drug, was responsible for the prevention of tumor growth and bone destruction, we implanted SRC into osteopetrotic rat tibia. SRC-induced bone destruction and tumor growth were impaired in osteopetrotic bone compared with control bone. The results from our animal model demonstrate that osteoclasts contribute to chondrosarcoma-mediated bone destruction and tumor growth and may represent a therapeutic target in particular chondrosarcoma patients. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1562-1571, 2014. PMID:25125336

Otero, Jesse E; Stevens, Jeff W; Malandra, Allison E; Fredericks, Douglas C; Odgren, Paul R; Buckwalter, Joseph A; Morcuende, Jose

2014-12-01

100

Inhibition of radish germination and root growth by coumarin and phenylpropanoids  

Microsoft Academic Search

Thirteen natural and synthetic phenylpropanoids as well as coumarin (2×104M) were tested for their biological activity on radish germination and subsequent root growth in light and darkness. Coumarin was the most potent inhibitor. With some exceptions, phenylpropanoids with a carboxylic group in the side chain inhibited root growth. Coumarin was formed spontaneously by photooxidation of 2-hydroxycinnamic acid. Microscopic observations of

G. Aliotta; G. Cafiero; A. Fiorentino; S. Strumia

1993-01-01

101

Ligands for Peroxisome Proliferator-Activated Receptorgamma and Retinoic Acid Receptor Inhibit Growth and Induce Apoptosis of Human Breast Cancer Cells in vitro and in BNX Mice  

Microsoft Academic Search

Induction of differentiation and apoptosis in cancer cells through ligands of nuclear hormone receptors (NHRs) is a novel and promising approach to cancer therapy. All-trans-retinoic acid (ATRA), an RA receptor-specific NHR ligand, is now used for selective cancers. The NHR, peroxisome proliferator-activated receptor gamma (PPARgamma ) is expressed in breast cancer cells. Activation of PPARgamma through a synthetic ligand, troglitazone

Elena Elstner; Carsten Muller; Kozo Koshizuka; Elizabeth A. Williamson; Dorothy Park; Hiroya Asou; Peter Shintaku; Jonathan W. Said; David Heber; H. Phillip Koeffler

1998-01-01

102

Azadirachtin Interacts with Retinoic Acid Receptors and Inhibits Retinoic Acid-mediated Biological Responses*  

PubMed Central

Considering the role of retinoids in regulation of more than 500 genes involved in cell cycle and growth arrest, a detailed understanding of the mechanism and its regulation is useful for therapy. The extract of the medicinal plant Neem (Azadirachta indica) is used against several ailments especially for anti-inflammatory, anti-itching, spermicidal, anticancer, and insecticidal activities. In this report we prove the detailed mechanism on the regulation of retinoic acid-mediated cell signaling by azadirachtin, active components of neem extract. Azadirachtin repressed all trans-retinoic acid (ATRA)-mediated nuclear transcription factor ?B (NF-?B) activation, not the DNA binding but the NF-?B-dependent gene expression. It did not inhibit I?B? degradation, I?B? kinase activity, or p65 phosphorylation and its nuclear translocation but inhibited NF-?B-dependent reporter gene expression. Azadirachtin inhibited TRAF6-mediated, but not TRAF2-mediated NF-?B activation. It inhibited ATRA-induced Sp1 and CREB (cAMP-response element-binding protein) DNA binding. Azadirachtin inhibited ATRA binding with retinoid receptors, which is supported by biochemical and in silico evidences. Azadirachtin showed strong interaction with retinoid receptors. It suppressed ATRA-mediated removal of retinoid receptors, bound with DNA by inhibiting ATRA binding to its receptors. Overall, our data suggest that azadirachtin interacts with retinoic acid receptors and suppresses ATRA binding, inhibits falling off the receptors, and activates transcription factors like CREB, Sp1, NF-?B, etc. Thus, azadirachtin exerts anti-inflammatory and anti-metastatic responses by a novel pathway that would be beneficial for further anti-inflammatory and anti-cancer therapies. PMID:21127062

Thoh, Maikho; Babajan, Banaganapalli; Raghavendra, Pongali B.; Sureshkumar, Chitta; Manna, Sunil K.

2011-01-01

103

Role of volatile acids in development of the cecal microflora in broilers chickens during growth  

Microsoft Academic Search

It is known that volatile fatty acids can inhibit growth of species of the family Enterobacteriaceae in vitro. However, whether these volatile fatty acids affect bacterial populations in the ceca of chickens is unknown. Therefore, a study was conducted to investigate if changes in volatile fatty acids in ceca of broiler chickens during growth affect bacterial populations. Results showed that

Wielen van der P. W. J. J; STEEF BIESTERVELD; S. Notermans; H. Hofstra; B. A. P. Urlings; F. van Knapen

2000-01-01

104

Inhibition kinetics of polyphenol oxidase by glutamic acid  

Microsoft Academic Search

The inhibition of polyphenol oxidase (PPO) by glutamic acid was investigated. Application of different concentrations of glutamic\\u000a acid to mushroom solution and Ocimum basilicum L. extract showed that glutamic acid appeared to be an effective browning inhibitor. Glutamic acid showed uncompetitive inhibition\\u000a for mushroom and Ocimum basilicum L. polyphenol oxidases using 4-methylcatechol as a substrate, for mushroom PPO using catechol

Serap Do?an; P?nar Turan; Mehmet Do?an; Mahir Alkan; Oktay Arslan

2007-01-01

105

Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid  

SciTech Connect

Citric acid has been shown to act as an agent for increasing the solubility of aluminum oxyhydroxides in aqueous solutions of high (>2.47 mol/mol) hydroxide-to-aluminum ratios. Conversely, citric acid also colloidally stabilizes particles in aqueous suspensions of aluminum-containing particles. Solutions of aluminum chloride, with and without citric acid added, were titrated with NaO(aq). The presence and size of particles were determined using quasi-elastic light scattering. In solutions that contained no citric acid, particles formed instantaneously when NaOH(aq) was added but these were observed to rapidly diminish in size, disappearing at OH/Al ratios below 2.5 mol/mol. When the OH/Al ratio was raised beyond 2.5 by addingmoreNaOH(aq), suspensions of colloidally stable particles formed. Large polycations containing 13 aluminum atoms were detected by 27Al solution NMR in citric-acid-free solutions with OH/Al ratios slightly lower than 2.5. In comparison, adding citric acid to solutions of aluminum chloride inhibited the formation of large aluminum-containing polycations. The absence of the polycations prevents or retards the subsequent formation of particles, indicating that the polycations, when present, act as seeds to the formation of new particles. Particles did not form in solutions with a citric acid/aluminum ratio of 0.8 until sufficient NaOH(aq) was added to raise the OH/Al ratio to 3.29. By comparison, lower amounts of citric acid did not prevent particles from forming but did retard the rate of growth.

Dabbs, Daniel M.; Ramachandran, Usha; Lu, Sang; Liu, Jun; Wang, Li Q.; Aksay, Ilhan A.

2005-12-06

106

Kinetics modeling of inhibition and utilization of mixed volatile fatty acids in the formation of polyhydroxyalkanoates by Ralstonia eutropha  

Microsoft Academic Search

Acetic, propionic and butyric acids are the major fermentation acids produced on acidogenesis of organic wastes such as food scraps. They can be utilized by Ralstonia eutropha as sole carbon sources for cell growth and polyhydroxyalkanoate (PHA) synthesis. The acids, however, are inhibitory and toxic to the bacterium depending on the medium pH and the total acid concentration. The inhibition

Jian Yu; Yingtao Si; Wan Keung; R. Wong

2002-01-01

107

2,3-Dihydroxybenzoic Acid Electrospun into Poly(D,L-lactide) (PDLLA)/Poly(ethylene oxide) (PEO) Nanofibers Inhibited the Growth of Gram-Positive and Gram-Negative Bacteria.  

PubMed

Widespread emergence of antibiotic-resistant pathogens in recent years has restricted the treatment options for various infectious diseases. Investigation of alternative antimicrobial agents and therapies is thus of utmost importance. Electrospinning of 50 mg/ml 2,3-dihydroxybenzoic acid (DHBA) into 24 % (w/v) poly(D,L-lactide) (PDLLA) and poly(ethylene oxide) (PEO) (1:1) produced nanofibers with an average diameter of 401 ± 122 nm. DHBA released from the nanofibers (315 ± 0.04 µg/ml within 2 h) inhibited the growth of Pseudomonas aeruginosa Xen 5, Klebsiella pneumoniae Xen 39, Escherichia coli Xen 14, Salmonella typhimurium Xen 26, and Staphylococcus aureus strains Xen 30, Xen 31, and Xen 36. The reason for the rapid diffusion of DHBA from PEO:PDLLA may be due to formation of hydrogen bonds between the hydroxyl groups of DHBA and the C=O groups of the PDLLA. DHBA formed a strong interaction with PDLLA and increased the thermal stability of the nanofiber mesh. The DHBA-containing nanofibers were non-hemolytic, suggesting that they may be incorporated in the development of a wound dressing. PMID:24934995

Ahire, Jayesh J; Neppalli, Ramesh; Heunis, Tiaan D J; van Reenen, Albert J; Dicks, Leon M T

2014-11-01

108

Inhibition of the gravitropic bending response of flowering shoots by salicylic acid.  

PubMed

The upward gravitropic bending of cut snapdragon, lupinus and anemone flowering shoots was inhibited by salicylic acid (SA) applied at 0.5 mM and above. This effect was probably not due to acidification of the cytoplasm, since other weak acids did not inhibit bending of snapdragon shoots. In order to study its mode of inhibitory action, we have examined in cut snapdragon shoots the effect of SA on three processes of the gravity-signaling pathway, including: amyloplast sedimentation, formation of ethylene gradient across the stem, and differential growth response. The results show that 1 mM SA inhibited differential ethylene production rates across the horizontal stem and the gravity-induced growth, without significantly inhibiting vertical growth or amyloplast sedimentation following horizontal placement. However, 5 mM SA inhibited all three gravity-induced processes, as well as the growth of vertical shoots, while increasing flower wilting. It may, therefore, be concluded that SA inhibits bending of various cut flowering shoots in a concentration-dependent manner. Thus, at a low concentration SA exerts its effect in snapdragon shoots by inhibiting processes operating downstream to stimulus sensing exerted by amyloplast sedimentation. At a higher concentration SA inhibits bending probably by exerting general negative effects on various cellular processes. PMID:14719525

Friedman, Haya; Meir, Shimon; Halevy, Abraham H; Philosoph-Hadas, Sonia

2003-10-01

109

Inhibition of hepatic glutathione-S-transferases by fatty acids and fatty acid esters.  

PubMed

Micromolar concentrations of polyunsaturated fatty acids and ascorbate esters of saturated fatty acids were found to cause a marked inhibition of rat and mouse hepatic glutathione-S-transferase (GST) activity towards 1-chloro-2,4-dinitrobenzene. Arachidonic acid was approximately 25 times more potent in inhibiting rat GST than palmitic acid which was the least effective. Both linoleic and arachidonic acids did not inhibit rat liver GST when ethacrynic acid was used as substrate while the reverse was true with 1,2-dichoro-4-nitrobenzene. In contrast, all the chemicals tested inhibited rat liver GST activity towards 4-nitropyridine N-oxide, indicating isozyme specificity. PMID:1949072

Mitra, A; Govindwar, S; Kulkarni, A P

1991-10-01

110

Inhibition of Growth of Mycobacterium smegmatis and of Cell Wall Synthesis by d-Serine  

PubMed Central

d-Serine inhibited the growth of Mycobacterium smegmatis and induced the morphological alteration of the bacilli. The growth inhibitory action of d-serine was partially reduced by an equimolecular concentration of d-alanine. The combination of glycine with d-alanine reversed the growth inhibition produced by d-serine more than did d-alanine alone. In cells cultured in the presence of d-serine, the amounts of alanine, diaminopimelic acid, and glycine inserted into the cell wall mucopeptide were reduced, and serine was increased. The intracellular accumulation of a precursor of cell wall mucopeptide was increased by d-serine, and this accumulation was reduced by d-alanine. d-Serine competed with glycine for incorporation into the cell wall mucopeptide. The incorporation of l-aspartic acid into diaminopimelic acid residues in the cell wall mucopeptide was markedly inhibited by d-serine. Three mutants resistant to d-serine were isolated by nitrosoguanidine treatment. In these mutants the effects of d-serine on the sites of cell wall mucopeptide synthesis were all reduced. Thus, d-serine inhibition of the growth is due to replacement of glycine residues of the cell wall mucopeptide with d-serine and inhibition of the cell wall synthesis by blocking the formation of d-alanine and diaminopimelic acid. PMID:15828163

Yabu, Kunihiko; Huempfner, Herman R.

1974-01-01

111

Cyanide inhibits respiration yet stimulates aerobic growth of Zymomonas mobilis  

Microsoft Academic Search

Potassium cyanide at submillimolar concentrations (20-500 lM) inhibited the high respiration rates of aerobic cultures of Zymomonas mobilis but, remarkably, stimulated culture growth. In batch culture, after an extended lag phase, exponential growth persisted longer, resulting in higher biomass densities. In aerobic chemostat cultures, elevated biomass concentration was observed in the presence of cyanide. This growth stimulation effect is attributed

Uldis Kalnenieks; Nina Galinina; Malda M. Toma; Robert K. Poole

112

Mechanism of Specific Inhibition of Phototropism by Phenylacetic Acid in Corn Seedling 1  

PubMed Central

Using geotropism as a control for phototropism, compounds similar to phenylacetic acid that photoreact with flavins and/or have auxin-like activity were examined for their ability to specifically inhibit phototropism in corn seedlings using geotropism as a control. Results using indole-3-acetic acid, napthalene-1-acetic acid, naphthalene-2-acetic acid, phenylacetic acid, and ?-phenylpyruvic acid suggest that such compounds will specifically inhibit phototropism primarily because of their photoreactivity with flavins and not their auxin activity. For example, strong auxins, indole-3-acetic acid and naphthalene-1-acetic acid, affected both tropic responses at all concentrations tested whereas weak auxins, phenylacetic acid and naphthalene-2-acetic acid, exhibited specific inhibition. In addition, the in vivo concentration of phenylacetic acid required to induce specificity was well below that required to stimulate coleoptile growth. Estimates of the percentage of photoreceptor pigment inactivated by phenylacetic acid (>10%) suggest that phenylacetic acid could be used to photoaffinity label the flavoprotein involved in corn seedling phototropism. PMID:16661774

Vierstra, Richard D.; Poff, Kenneth L.

1981-01-01

113

Multiple product inhibition and growth modeling of Clostridium butyricum and Klebsiella pneumoniae in glycerol fermentation  

Microsoft Academic Search

The inhibition potentials of products and substrate on the growth of Clostridium butyricum and Klebsiella pneumoniae in the glycerol fermentation are examined from experimental data and with a mathematical model. Whereas the inhibition potential of externally added and self-produced 1,3-propanediol is essentially the same, butyric acid produced by the culture is more toxic than that externally added. The same seems

A.-P. Zeng; A. Ross; H. Biebl; C. Tag; B. Guenzel; W.-D. Deckwer

1994-01-01

114

Novel Approaches to Inhibition of Gastric Acid Secretion  

PubMed Central

The gastric H,K-adenosine triphosphatase (ATPase) is the primary target for treatment of acid-related diseases. Proton pump inhibitors (PPIs) are weak bases composed of two moieties, a substituted pyridine with a primary pKa of about 4.0 that allows selective accumulation in the secretory canaliculus of the parietal cell, and a benzimidazole with a second pKa of about 1.0. Protonation of this benzimidazole activates these prodrugs, converting them to sulfenic acids and/or sulfenamides that react covalently with one or more cysteines accessible from the luminal surface of the ATPase. The maximal pharmacodynamic effect of PPIs as a group relies on cyclic adenosine monophosphate–driven H,K-ATPase translocation from the cytoplasm to the canalicular membrane of the parietal cell. At present, this effect can only be achieved with protein meal stimulation. Because of covalent binding, inhibitory effects last much longer than their plasma half-life. However, the short dwell-time of the drug in the blood and the requirement for acid activation impair their efficacy in acid suppression, particularly at night. All PPIs give excellent healing of peptic ulcer and produce good, but less than satisfactory, results in reflux esophagitis. PPIs combined with antibiotics eradicate Helicobacter pylori, but success has fallen to less than 80%. Longer dwell-time PPIs promise to improve acid suppression and hence clinical outcome. Potassium-competitive acid blockers (P-CABs) are another class of ATPase inhibitors, and at least one is in development. The P-CAB under development has a long duration of action even though its binding is not covalent. PPIs with a longer dwell time or P-CABs with long duration promise to address unmet clinical needs arising from an inability to inhibit nighttime acid secretion, with continued symptoms, delayed healing, and growth suppression of H. pylori reducing susceptibility to clarithromycin and amoxicillin. Thus, novel and more effective suppression of acid secretion would benefit those who suffer from acid-related morbidity, continuing esophageal damage and pain, nonsteroidal anti-inflammatory drug–induced ulcers, and nonresponders to H. pylori eradication. PMID:20924727

Shin, Jai Moo; Hunt, Richard

2010-01-01

115

Radiation-Induced Sprout and Growth Inhibition in  

E-print Network

HEALING HYDROLASES INHIBITION IONIZING RADIATION EFFECTS LYASES MUSHROOMS ONIONS OXALIC ACID PATHOGENESIS (Aiiium cepa L. and others) . . . . 37 2 . 2 . 4 . Mushrooms (A-jJttcuJ t u j ' V t u i (Lange) Singer) 38

116

Minocycline inhibits the growth of glioma by inducing autophagy.  

PubMed

Minocycline has been shown to alleviate several neurological disorders. Unexpectedly, we found that minocycline had opposite effects on glioma cells: minocycline induced nonapoptotic cell death in glioma cells. The glioma cell death was associated with the presence of autophagic vacuoles in the cytoplasm. Minocycline induced autophagy was confirmed by acridine orange, monodansylcadaverine (MDC) stainings of vesicle formation and the conversion of microtubule-associated proteins light chain 3 (LC3-I) to LC3-II. Pretreatment with autophagy inhibitor 3-methyladenine (3-MA) suppressed the induction of acidic vesicular organelles and the accumulation of LC3-II to the autophagosome membrane in glioma cells treated with minocycline. Despite the pretreatment of 3-MA, minocycline induced cell death which could result from the activation of caspase-3. Minocycline effectively inhibited tumor growth and induced autophagy in the xenograft tumor model of C6 glioma cells. These results suggest that minocycline may kill glioma cells by inducing autophagic cell death. When autophagy was inhibited, minocycline still induced cell death through the activation of caspase-3. Thus, minocycline is a promising agent in the treatment of malignant gliomas. PMID:21079420

Liu, Wei-Ting; Lin, Chia-Ho; Hsiao, Michael; Gean, Po-Wu

2011-02-01

117

PPAR regulates E-cadherin expression and inhibits growth and invasion of prostate  

E-print Network

PPAR regulates E-cadherin expression and inhibits growth and invasion of prostate cancer. Jean of E-cadherin, a protein involved in the control of cell migration and invasion is highly up-regulated in the presence of valproic acid and pioglitazone. We show that10 E-cadherin expression responds only

Paris-Sud XI, Université de

118

Inhibition of Myofibroblast Apoptosis by Transforming Growth Factor b 1  

Microsoft Academic Search

Fibroblast differentiation to the myofibroblast phenotype is associated with a -smooth-muscle actin ( a -SMA) expression and regulated by cytokines. Among these, transforming growth factor (TGF)- b 1 and interleukin (IL)-1 b can stimulate and inhibit myofibroblast differentiation, respectively. IL-1 b inhibits a -SMA expres- sion by inducing apoptosis selectively in myofibroblasts via induction of nitric oxide synthase (inducible nitric

Hong-Yu Zhang; Sem H. Phan

119

Tyrosinase inhibition by isophthalic acid: Kinetics and computational simulation  

Microsoft Academic Search

Using inhibition kinetics and computational simulation, we studied the reversible inhibition of tyrosinase by isophthalic acid (IPA). IPA inhibited tyrosinase in a complex manner with Ki=17.8±1.8mM. Measurements of intrinsic and ANS-binding fluorescence showed that IPA induced no changes in tertiary protein structure. For further insight, we predicted the 3D structure of tyrosinase and used a docking algorithm to simulate binding

Yue-Xiu Si; Shang-Jun Yin; Hae Young Chung; Li Yan; Zhi-Rong Lü; Hai-Meng Zhou; Jun-Mo Yang; Guo-Ying Qian; Yong-Doo Park

2011-01-01

120

Corrosion Inhibition of a Green Scale Inhibitor Polyepoxysuccinic Acid  

Microsoft Academic Search

The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic

Rong Chun XIONG; Qing ZHOU; Gang WEI

121

Growth of tobacco in short-day conditions leads to high starch, low sugars, altered diurnal changes in the Nia transcript and low nitrate reductase activity, and inhibition of amino acid synthesis.  

PubMed

Diurnal changes in carbohydrates and nitrate reductase (NR) activity were compared in tobacco (Nicotiana tabacum. L.cv. Gatersleben) plants growing in a long (18 h light/6 h dark) and a short (6 h light/18 h dark) day growth regime, or after short-term changes in the light regime. In long-day-grown plants, source leaves contained high levels of sugars throughout the light and dark periods. In short-day-grown plants, levels of sucrose and reducing sugars were very low at the end of the night and, although they rose during the light period, remained much lower than in long days and declined to very low levels again by the middle of the night. Starch accumulated more rapidly in short-day-than long-day-grown plants. Starch was completely remobilised during the night in short days, but not in long days. A single short day/long night cycle sufficed to stimulate starch accumulation during the following light period. In long-day-grown plants, the Nia transcript level was high at the end of the night, decreased during the day, and recovered gradually during the night. In short-day-grown plants, the Nia transcript level was relatively low at the end of the night, decreased to very low levels at the end of the light period, increased to a marked maximum in the middle of the night, and decreased during the last 5 h of the dark period. In long-day-grown plants, NR activity in source leaves rose by 2- to 3-fold in the first part of the light period and decreased in the second part of the light period. In short-day-grown plants, NR activity was low at the end of the night, and only increased slightly after illumination. Dark inactivation of source-leaf NR was partially reversed in long-day-grown plants, but not in short day-grown plants. In both growth regimes, mutants with one instead of four functional copies of the Nia gene had a 60% reduction in maximum NR activity in the source leaves, compared to wild-type plants. The diurnal changes in NR activity were almost completely suppressed in the mutants in long days, whereas the mutants showed similar or slightly larger diurnal changes than wild-type plants in short days. When short-day-grown plants were transferred to long-day conditions for 3 d, NR activity and the diurnal changes in NR activity resembled those in long-day-grown plants. Phloem export from source leaves of short-day-grown plants was partially inhibited by applying a cold-girdle for one light and dark cycle. The resulting increase in leaf sugar was accompanied by an marked increase in the Nia transcript level and a 2-fold increase in NR activity at the end of the dark period. When wild-type plants were subjected to a single short day/long night cycle of increasing severity, NR activity in source leaves at the end of the night decreased when the endogenous sugars declined below about 3 mumol hexose (g FW)-1. In sink leaves in short-day conditions, sugars were higher and the light-induced rise in NR activity was much larger than in source leaves on the same plants. The source leaves of wild-type plants in short-day conditions contained very high levels of nitrate, very low levels of glutamine, low levels of total amino acids, and lower protein and chlorophyll, compared to long-day-grown plants. Plants grown in short days had relatively high levels of glutamate and aspartate, and extremely low levels of most of the minor amino acids in their source leaves at the end of the night. Illumination led to a decrease in glutamate and an increase in the minor amino acids. A single short day/long night cycle led to an increase in glutamate, and a large decrease in the minor acids at the end of the dark period, and reillumination led to a decrease in glutamate and an increase in the minor amino acids. It is proposed that sugar-mediated control of Nia expression and NR activity overrides regulation by nitrogenous compounds when sugars are in short supply, resulting in a severe inhibition of nitrate assimilation. It is also proposed that su PMID:9951717

Matt, P; Schurr, U; Klein, D; Krapp, A; Stitt, M

1998-12-01

122

The immunosuppressant FK506 inhibits amino acid import in Saccharomyces cerevisiae.  

PubMed Central

The immunosuppressants cyclosporin A, FK506, and rapamycin inhibit growth of unicellular eukaryotic microorganisms and also block activation of T lymphocytes from multicellular eukaryotes. In vitro, these compounds bind and inhibit two different types of peptidyl-prolyl cis-trans isomerases. Cyclosporin A binds cyclophilins, whereas FK506 and rapamycin bind FK506-binding proteins (FKBPs). Cyclophilins and FKBPs are ubiquitous, abundant, and targeted to multiple cellular compartments, and they may fold proteins in vivo. Previously, a 12-kDa cytoplasmic FKBP was shown to be only one of at least two FK506-sensitive targets in the yeast Saccharomyces cerevisiae. We find that a second FK506-sensitive target is required for amino acid import. Amino acid-auxotrophic yeast strains (trp1 his4 leu2) are FK506 sensitive, whereas prototrophic strains (TRP1 his4 leu2, trp1 HIS4 leu2, and trp1 his4 LEU2) are FK506 resistant. Amino acids added exogenously to the growth medium mitigate FK506 toxicity. FK506 induces GCN4 expression, which is normally induced by amino acid starvation. FK506 inhibits transport of tryptophan, histidine, and leucine into yeast cells. Lastly, several genes encoding proteins involved in amino acid import or biosynthesis confer FK506 resistance. These findings demonstrate that FK506 inhibits amino acid import in yeast cells, most likely by inhibiting amino acid transporters. Amino acid transporters are integral membrane proteins which import extracellular amino acids and constitute a protein family sharing 30 to 35% identity, including eight invariant prolines. Thus, the second FK506-sensitive target in yeast cells may be a proline isomerase that plays a role in folding amino acid transporters during transit through the secretory pathway. Images PMID:7687745

Heitman, J; Koller, A; Kunz, J; Henriquez, R; Schmidt, A; Movva, N R; Hall, M N

1993-01-01

123

In Vitro Measurement of Pollen Tube Growth Inhibition  

PubMed Central

A method for estimating inhibition of pollen tube growth was developed. Pollen is placed in straight lines on an agar surface where it responds uniformly and predictably to aqueous solutions of germination-inhibiting substances located in wells at the ends of the lines. A scale of ratings, roughly corresponding to serial, doubled concentrations of inhibiting substances, was devised. Water-soluble organic solvents are relatively noninhibitory, salts are variable, and metabolic inhibitors have strong inhibitory effects. Pollens differ in their susceptibility to inhibition and in their response to particular substances. PMID:16658085

Martin, Franklin W.

1972-01-01

124

Timing of growth inhibition following shoot inversion in Pharbitis nil  

NASA Technical Reports Server (NTRS)

Shoot inversion in Pharbitis nil results in the enhancement of ethylene production and in the inhibition of elongation in the growth zone of the inverted shoot. The initial increase in ethylene production previously was detected within 2 to 2.75 hours after inversion. In the present study, the initial inhibition of shoot elongation was detected within 1.5 to 4 hours with a weighted mean of 2.4 hours. Ethylene treatment of upright shoots inhibited elongation in 1.5 hours. A cause and effect relationship between shoot inversion-enhanced ethylene production and inhibition of elongation cannot be excluded.

Abdel-Rahman, A. M.; Cline, M. G.

1989-01-01

125

Stereospecificity of amino acid hydroxamate inhibition of aminopeptidases.  

PubMed

Hydroxamates of amino acids and aliphatic acids are effective inhibitors of Aeromonas proteolytica amino-peptidase (EC 3.4.11.10) and of both the cytosolic (EC 3.4.11.1) and microsomal (EC 3.4.11.2) aminopeptidases of swine kidney. Cytosolic leucine aminopeptidase and the Aeromonas enzyme were inhibited to a greater extent by D isomers than by the L enantiomorphs, manganese-activated kidney cytosolic leucine aminopeptidase being inhibited 10 times more effectively by D-leucine and D-valine hydroxamic acids than by the L isomers. The D isomers of these two compounds inhibited Aeromonas aminopeptidase to an even greater extent with Ki values of 2 X 10(-9) and 5 X 10(-9), respectively, whereas the corresponding L isomers were bound 150 times less tightly. With the Aeromonas enzyme, a comparison of inhibition by racemic mixtures with that of the corresponding L isomers indicated that in all cases the contribution of the D isomer was predominant. Isocaproic hydroxamic acid inhibited this enzyme equally well as L-leucine hydroxamic acid, indicating that the amino group orientation in the D isomer contributes to the binding efficacy. Swine kidney microsomal aminopeptidase was also inhibited by D isomers of leucine and valine hydroxamic acids but in contrast to the other two enzymes, the inhibition was 10-fold less than that observed for the corresponding L isomers. Cytosolic leucine aminopeptidase with either 6 g atoms of zinc per mol or 12 g atoms of zinc per mol was inhibited only slightly by any of the hydroxamic acid compounds; evidently enzyme-bound manganese (or magnesium) is specific for hydroxamate binding to this aminopeptidase. PMID:6643439

Wilkes, S H; Prescott, J M

1983-11-25

126

Mullerian inhibiting substance inhibits ovarian cell growth through an Rb-independent mechanism.  

PubMed

Müllerian inhibiting substance (MIS), a transforming growth factor-beta family member, causes regression of the Müllerian duct in male embryos. MIS overexpression in transgenic mice ablates the ovary, and MIS inhibits the growth of ovarian cancer cell lines in vitro, suggesting a key role for this hormone in postnatal development of the ovary. This report describes a mechanism for MIS-mediated growth inhibition in both a human epithelial ovarian cancer cell line and a cell line derived from normal ovarian surface epithelium, which is the origin of human epithelial ovarian cancers. MIS-treated cells accumulated in the G(1) phase of the cell cycle and subsequently underwent apoptosis. MIS up-regulated the cyclin-dependent kinase inhibitor p16 through an MIS type II receptor-mediated mechanism and inhibited growth in the absence of detectable or inactive Rb protein. Prolonged treatment with MIS down-regulated the Rb-related protein p130 and increased the Rb family-regulated transcription factor E2F1, overexpression of which inhibited growth. These findings demonstrate that p16 is required for MIS-mediated growth inhibition in ovarian epithelial cells and tumor cells and suggest that up-regulation of E2F1 also plays a role in this process. PMID:10958795

Ha, T U; Segev, D L; Barbie, D; Masiakos, P T; Tran, T T; Dombkowski, D; Glander, M; Clarke, T R; Lorenzo, H K; Donahoe, P K; Maheswaran, S

2000-11-24

127

D-amino acids indirectly inhibit biofilm formation in Bacillus subtilis by interfering with protein synthesis.  

PubMed

The soil bacterium Bacillus subtilis forms biofilms on surfaces and at air-liquid interfaces. It was previously reported that these biofilms disassemble late in their life cycle and that conditioned medium from late-stage biofilms inhibits biofilm formation. Such medium contained a mixture of D-leucine, D-methionine, D-tryptophan, and D-tyrosine and was reported to inhibit biofilm formation via the incorporation of these D-amino acids into the cell wall. Here, we show that L-amino acids were able to specifically reverse the inhibitory effects of their cognate D-amino acids. We also show that D-amino acids inhibited growth and the expression of biofilm matrix genes at concentrations that inhibit biofilm formation. Finally, we report that the strain routinely used to study biofilm formation has a mutation in the gene (dtd) encoding D-tyrosyl-tRNA deacylase, an enzyme that prevents the misincorporation of D-amino acids into protein in B. subtilis. When we repaired the dtd gene, B. subtilis became resistant to the biofilm-inhibitory effects of D-amino acids without losing the ability to incorporate at least one noncanonical D-amino acid, D-tryptophan, into the peptidoglycan peptide side chain. We conclude that the susceptibility of B. subtilis to the biofilm-inhibitory effects of D-amino acids is largely, if not entirely, due to their toxic effects on protein synthesis. PMID:24097941

Leiman, Sara A; May, Janine M; Lebar, Matthew D; Kahne, Daniel; Kolter, Roberto; Losick, Richard

2013-12-01

128

Inhibition of activation of dsRNA-dependent protein kinase and tumour growth inhibition  

Microsoft Academic Search

Inhibition of dsRNA-activated protein kinase (PKR), not only attenuates muscle atrophy in a murine model of cancer cachexia\\u000a (MAC16), but it also inhibits tumour growth. In vitro the PKR inhibitor maximally inhibited growth of MAC16 tumour cells at\\u000a a concentration of 200 nM, which was also maximally effective in attenuating phosphorylation of PKR and of eukaryotic initiation\\u000a factor (eIF)2 on the ?-subunit.

Helen L. Eley; Pria S. McDonald; Steven T. Russell; Michael J. Tisdale

2009-01-01

129

Amino acid transport inhibition: brain and behavioral correlates.  

PubMed

In vivo inhibition of uptake 14C-L-valine by brain following subcutaneous administration of either of two gamma-glutamyl cycle enzyme inhibitors, 2-imidazolidone-4-carboxylic acid (ICA), or, L-methionine-S-sulfoximine (MSO) is documented in C57BL/6J mice. Dose related decrease in exploratory activity, impairment of memory for foot shock, and reduced operant responding for food reinforcement parallels the time course for interference with uptake of a large neutral amino acid by these two compounds previously shown to inhibit different enzymes in the gamma-glutamyl cycle subserving active amino acid transport. PMID:981286

Randt, C T; Samuels, S; Fish, I

1976-06-01

130

Inhibition of stem growth and gibberellin production in Agrostemma githago L. by the growth retardant tetcyclacis.  

PubMed

The effects of the new growth retardant tetcyclacis (TCY) on stem growth and endogenous gibberellin (GA) levels were investigated in the long-day rosette plant Agrostemma githago. Application of TCY (10 ml of a 5·10(-5)M solution daily) to the soil suppressed stem elongation in Agrostemma grown under long-day conditions. A total of 10 ?g GA1 (1 ?g applied on alternate days) per plant overcame the growth retardation caused by TCY.Control plants and plants treated with TCY were analyzed for endogenous GAs after exposure to nine long days. The acidic extracts were fractionated by high-performance liquid chromatography. Part of each fraction was tested in the d-5 maize bioassay, while the remainder was analyzed by combined gas chromatography-selected ion monitoring. The bioassay results indicated that the GA content of plants treated with TCY was much lower than that of untreated plants. The data obtained by gas chromatography-selected ion monitoring confirmed that the levels of seven GAs present in Agrostemma were much reduced in TCY-treated plants when compared with the levels in control plants: GA53 (13%), GA44 (0%), GA19 (1%), GA17 (33%), GA20 (15%), GA1 (4%), and epi-GA1 (13%). These results provide evidence that TCY inhibits stem growth in Agrostemma by blocking GA biosynthesis and thus lowering the levels of endogenous GAs. PMID:24241444

Zeevaart, J A

1985-10-01

131

Oligodendrocytes Arrest Neurite Growth by Contact Inhibition  

Microsoft Academic Search

We have used video time-lapse microscopy to analyze in vitro the interactions of growth cones of newborn rat dorsal root ganglion cells with dissociated young rat CNS glial cells present in the cultures at low density. To provide optimal conditions for neurite extension, cells were grown on laminin and in NGF-supplemented medium. Our initial observations showed that there are 2

Christine Bandtlow; Thomas Zachleder; Martin E. Schwab

1990-01-01

132

Plant pathology Growth inhibition of Agaricus bisporus  

E-print Network

Agaricus bisporus and 3 isolates of thermophilic fungi active in mushroom composting. At concentrations is selective for the growth of mushroom mycelium. Among these microorganisms, ther- #12;mophilic fungi appear fungi in mushroom compost (Ross and Harris, 1983; Straatsma et al, 1989). Fungicides are used during

Paris-Sud XI, Université de

133

Inhibition by arachidonic acid and other fatty acids of dopamine uptake at the human dopamine transporter  

Microsoft Academic Search

It is known that arachidonic acid, in addition to promoting release of dopamine, can inhibit its transport. The present study provides preliminary information on structure–activity relationships for uptake inhibition by rotating disk voltammetry in human embryonic kidney-293 cells expressing the human dopamine transporter. Except for anandamide, all other fatty acids studied at a pretreatment concentration of 80 ?M caused significant

Nianhang Chen; Michael Appell; Janet L. Berfield; Maarten E. A. Reith

2003-01-01

134

Transcriptional profile of maize roots under acid soil growth  

PubMed Central

Background Aluminum (Al) toxicity is one of the most important yield-limiting factors of many crops worldwide. The primary symptom of Al toxicity syndrome is the inhibition of root growth leading to poor water and nutrient absorption. Al tolerance has been extensively studied using hydroponic experiments. However, unlike soil conditions, this method does not address all of the components that are necessary for proper root growth and development. In the present study, we grew two maize genotypes with contrasting tolerance to Al in soil containing toxic levels of Al and then compared their transcriptomic responses. Results When grown in acid soil containing toxic levels of Al, the Al-sensitive genotype (S1587-17) showed greater root growth inhibition, more Al accumulation and more callose deposition in root tips than did the tolerant genotype (Cat100-6). Transcriptome profiling showed a higher number of genes differentially expressed in S1587-17 grown in acid soil, probably due to secondary effects of Al toxicity. Genes involved in the biosynthesis of organic acids, which are frequently associated with an Al tolerance response, were not differentially regulated in both genotypes after acid soil exposure. However, genes related to the biosynthesis of auxin, ethylene and lignin were up-regulated in the Al-sensitive genotype, indicating that these pathways might be associated with root growth inhibition. By comparing the two maize lines, we were able to discover genes up-regulated only in the Al-tolerant line that also presented higher absolute levels than those observed in the Al-sensitive line. These genes encoded a lipase hydrolase, a retinol dehydrogenase, a glycine-rich protein, a member of the WRKY transcriptional family and two unknown proteins. Conclusions This work provides the first characterization of the physiological and transcriptional responses of maize roots when grown in acid soil containing toxic levels of Al. The transcriptome profiles highlighted several pathways that are related to Al toxicity and tolerance during growth in acid soil. We found several genes that were not found in previous studies using hydroponic experiments, increasing our understanding of plant responses to acid soil. The use of two germplasms with markedly different Al tolerances allowed the identification of genes that are a valuable tool for assessing the mechanisms of Al tolerance in maize in acid soil. PMID:20828383

2010-01-01

135

Bile acid synthesis by cultured hepatocytes. Inhibition by mevinolin, but not by bile acids.  

PubMed

The ability of cultured hepatocytes to maintain a constant rate of bile acid synthesis and secretion in a chemically defined serum-free culture medium allowed us to examine the direct effects of bile acids on their synthesis. Mass quantitation of bile acids by gas liquid chromatography showed that adding taurochenodeoxycholate at concentrations which were from 2 to 20 times the concentration of bile acids found in rat portal blood increased rather than decreased the secretion of cholic acid. Using a more direct approach to measure relative rates of bile acid synthesis and secretion, we determined the rate of de novo 14C-bile acid synthesis. Adding taurocholate at concentrations ranging from 2 to 60 times the concentration found in rat portal blood did not inhibit 14C-bile acid synthesis. Furthermore, free and conjugated di- and tri-hydroxy bile acids did not inhibit bile acid synthesis. In contrast, mevinolin, a potent inhibitor of cholesterol biosynthesis, inhibited 14C-bile acid synthesis by 63%. Since previous demonstration of bile acid negative feedback regulation was achieved in vivo by infusing taurocholate into the intestines of bile-diverted rats, we examined the possibility that bile acid synthesis must be induced in order for bile acids to inhibit their synthesis. Hepatocytes obtained from bile-diverted rats exhibited a 5-fold increase in the synthesis and secretion of 14C-bile acids. However, taurocholate did not inhibit bile acid synthesis by cells from bile-diverted rats. These data show that bile acids do not interact directly with the hepatocyte to inhibit their synthesis. PMID:6550600

Davis, R A; Highsmith, W E; McNeal, M M; Schexnayder, J A; Kuan, J C

1983-04-10

136

Spectroscopic analysis of urinary calculi and inhibition of their growth  

NASA Astrophysics Data System (ADS)

We present here a study of kidney stone formation and growth inhibition based on a traditional medicine approach with Aquatica Lour (RAL) herbal extracts. Kidney stone material systems were synthesized in vitro using a simplified single diffusion gel growth technique. With the objective of revealing the mechanism of inhibition of calculi formation by RAL extracts, samples prepared without the presence of extract, and with the presence of extract, were analyzed using Raman, photoluminescence, and XPS. The unexpected presence of Zn revealed by XPS in a sample prepared with RAL provides an explanation for the inhibition process, and also explains the dramatic reflectance of incident light observed in attempts to obtain infrared transmission data. Raman data are consistent with the binding of the inhibitor to the oxygen of the kidney stone. Photoluminescence data corroborate with the other results to provide additional evidence of Zn-related inhibition.

Manciu, Felicia; Durrer, William; Govani, Jayesh; Reza, Layra; Pinales, Luis

2009-10-01

137

Pharmacological Inhibition of BMK1 Suppresses Tumor Growth Through PML  

PubMed Central

SUMMARY BMK1 is activated by mitogens and oncogenic signals and, thus, is strongly implicated in tumorigenesis. We found that BMK1 interacted with promyelocytic leukemia protein (PML), and inhibited its tumor-suppressor function through phosphorylation. Furthermore, activated BMK1 notably inhibited PML-dependent activation of p21. To further investigate the BMK-mediated inhibition of the tumor suppressor activity of PML in tumor cells, we developed a small-molecule inhibitor of the kinase activity of BMK1, XMD8-92. Inhibition of BMK1 by XMD8-92 blocked tumor cell proliferation in vitro and significantly inhibited tumor growth in vivo by 95%, demonstrating the efficacy and tolerability of BMK1-targeted cancer treatment in animals. PMID:20832753

Yang, Qingkai; Deng, Xianming; Lu, Bingwen; Cameron, Michael; Fearns, Colleen; Patricelli, Matthew P.

2010-01-01

138

Growth of nitric acid hydrates on thin sulfuric acid films  

NASA Technical Reports Server (NTRS)

Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

1994-01-01

139

Bacterial Ammonia Causes Significant Plant Growth Inhibition  

PubMed Central

Many and complex plant-bacteria inter-relationships are found in the rhizosphere, since plants release a variety of photosynthetic exudates from their roots and rhizobacteria produce multifaceted specialized compounds including rich mixtures of volatiles, e.g., the bouquet of Serratia odorifera 4Rx13 is composed of up to 100 volatile organic and inorganic compounds. Here we show that when growing on peptone-rich nutrient medium S. odorifera 4Rx13 and six other rhizobacteria emit high levels of ammonia, which during co-cultivation in compartmented Petri dishes caused alkalization of the neighboring plant medium and subsequently reduced the growth of A. thaliana. It is argued that in nature high-protein resource degradations (carcasses, whey, manure and compost) are also accompanied by bacterial ammonia emission which alters the pH of the rhizosphere and thereby influences organismal diversity and plant-microbe interactions. Consequently, bacterial ammonia emission may be more relevant for plant colonization and growth development than previously thought. PMID:23691060

Weise, Teresa; Kai, Marco; Piechulla, Birgit

2013-01-01

140

Alkyl hydroxybenzoic acid derivatives that inhibit HIV-1 protease dimerization.  

PubMed

The therapeutic potential of gallic acid and its derivatives as anti-cancer, antimicrobial and antiviral agents is well known. We have examined the mechanism by which natural gallic acid and newly synthesized gallic acid alkyl esters and related protocatechuic acid alkyl esters inhibit HIV-1 protease to compare the influence of the aromatic ring substitutions on inhibition. We used Zhang-Poorman's kinetic analysis and fluorescent probe binding to demonstrate that several gallic and protecatechuic acid alkyl esters inhibited HIV-1 protease by preventing the dimerization of this obligate homodimeric aspartic protease rather than targeting the active site. The tri-hydroxy substituted benzoic moiety in gallates was more favorable than the di-substituted one in protocatechuates. In both series, the type of inhibition, its mechanism and the inhibitory efficiency dramatically depended on the length of the alkyl chain: no inhibition with alkyl chains less than 8 carbon atoms long. Molecular dynamics simulations corroborated the kinetic data and propose that gallic esters are intercalated between the two N- and C-monomer ends. They complete the ?-sheet and disrupt the dimeric enzyme. The best gallic ester (14 carbon atoms, K(id) of 320 nM) also inhibited the multi-mutated protease MDR-HM. These results will aid the rational design of future generations of non-peptide inhibitors of HIV-1 protease dimerization that inhibit multi-mutated proteases. Finally, our work suggests the wide use of gallic and protocatechuic alkyl esters to dissociate intermolecular ?-sheets involved in protein-protein interactions. PMID:22963666

Flausino, O A; Dufau, L; Regasini, L O; Petrônio, M S; Silva, D H S; Rose, T; Bolzani, V S; Reboud-Ravaux, M

2012-01-01

141

Inhibition of ATP citrate lyase induces triglyceride accumulation with altered fatty acid composition in cancer cells.  

PubMed

De novo lipogenesis is activated in most cancers and several lipogenic enzymes have been implicated as therapeutic targets. Here, we demonstrate a novel function of the lipogenic enzyme, ATP citrate lyase (ACLY), in lipid metabolism in cancer cells. ACLY depletion by small interfering RNAs caused growth suppression and/or apoptosis in a subset of cancer cell lines. To investigate the effect of ACLY inhibition on lipid metabolism, metabolome and transcriptome analysis was performed. ACLY depletion blocks the fatty acid chain elongation from C16 to C18 in triglyceride (TG), but not in other lipid classes. Meanwhile, wild-type ACLY overexpression enhanced fatty acid elongation of TG, whereas an inactive mutant ACLY did not change it. ACLY depletion-mediated blockade of fatty acid elongation was coincident with downregulation of long-chain fatty acid elongase ELOVL6, which resides in endoplasmic reticulum (ER). Paradoxically, ACLY depletion-mediated growth suppression was associated with TG accumulation. ACLY depletion downregulated the expression of carnitine palmitoyltransferase 1A, which is a mitochondrial fatty acid transporter. Consistent with this finding, metabolome analysis revealed that ACLY positively regulates the carnitine system, which plays as an essential cofactor for fatty acid transport across mitochondrial membrane. AICAR, an activator of mitochondrial fatty acid oxidation (FAO), significantly reduced ACLY depletion-mediated TG accumulation. These data indicate that inhibition of ACLY might affect both fatty acid elongation in ER and FAO in mitochondria, thereby explaining the TG accumulation with altered fatty acid composition. This phenotype may be a hallmark of growth suppression mediated by ACLY inhibition. PMID:24310723

Migita, Toshiro; Okabe, Sachiko; Ikeda, Kazutaka; Igarashi, Saori; Sugawara, Shoko; Tomida, Akihiro; Soga, Tomoyoshi; Taguchi, Ryo; Seimiya, Hiroyuki

2014-07-01

142

All-trans retinoic acid combined with 5-Aza-2 Prime -deoxycitidine induces C/EBP{alpha} expression and growth inhibition in MLL-AF9-positive leukemic cells  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We tested whether ATRA and 5-Aza affect AML cell differentiation and growth. Black-Right-Pointing-Pointer Cell differentiation and growth arrest were induced in MLL-AF9-expressing cells. Black-Right-Pointing-Pointer Increased expression of C/EBP{alpha}, C/EBP{epsilon}, and PU.1 were also observed. Black-Right-Pointing-Pointer MLL-AF4/AF5q31-expressing cells are less sensitive to ATRA and 5-Aza. Black-Right-Pointing-Pointer Different MLL fusion has distinct epigenetic properties related to RA pathway. -- Abstract: The present study tested whether all-trans retinoic acid (ATRA) and 5-Aza-2 Prime -deoxycitidine (5-Aza) affect AML cell differentiation and growth in vitro by acting on the CCAAT/enhancer binding protein {alpha} (C/EBP{alpha}) and c-Myc axis. After exposure to a combination of these agents, cell differentiation and growth arrest were significantly higher in human and murine MLL-AF9-expressing cells than in MLL-AF4/AF5q31-expressing cells, which were partly associated with increased expression of C/EBP{alpha}, C/EBP{epsilon}, and PU.1, and decreased expression of c-Myc. These findings indicate that MLL-AF9-expressing cells are more sensitive to ATRA and 5-Aza, indicating that different MLL fusion proteins possess different epigenetic properties associated with retinoic acid pathway inactivation.

Fujiki, Atsushi [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan)] [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan); Imamura, Toshihiko, E-mail: imamura@koto.kpu-m.ac.jp [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan)] [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan); Sakamoto, Kenichi; Kawashima, Sachiko; Yoshida, Hideki; Hirashima, Yoshifumi; Miyachi, Mitsuru; Yagyu, Shigeki; Nakatani, Takuya [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan)] [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan); Sugita, Kanji [Department of Pediatrics, University of Yamanashi, Yamanashi (Japan)] [Department of Pediatrics, University of Yamanashi, Yamanashi (Japan); Hosoi, Hajime [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan)] [Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto (Japan)

2012-11-16

143

IL-1? inhibits axonal growth of developing sympathetic neurons.  

PubMed

Several secreted proteins facilitate the growth and guidance of sympathetic axons to their target organs during development. Here we show that IL-1?, a key regulator of inflammation in the immune system, inhibits axonal growth and branching from cultured sympathetic neurons at a stage in development when their axons are ramifying within their targets in vivo. IL-1? is synthesised in sympathetic ganglia and its targets at this stage, and IL-1? protein is detectable in the axons and perikarya of the innervating neurons. It acts directly on developing axons to inhibit their growth via NF-?B signalling. These findings show that IL-1? is a novel locally, and target-derived factor that can regulate the extent of sympathetic axon growth during the late embryonic and early postnatal period in developing rat sympathetic neurons. PMID:21791245

Nolan, Aoife M; Nolan, Yvonne M; O'Keeffe, Gerard W

2011-10-01

144

Kaurenoic Acid from Aralia continentalis Inhibits Biofilm Formation of Streptococcus mutans.  

PubMed

We isolated a single chemical compound from A. continentalis and identified it to be kaurenoic acid (KA) and investigated the influence of anticariogenic properties. Inhibitory effects of KA on cariogenic properties such as growth, acid production, biofilm formation, and the adherence of S. mutans were evaluated. Furthermore, real-time PCR analysis was performed to evaluate the influence of KA on the genetic expression of virulence factors. KA significantly inhibited the growth and acid production of S. mutans at 2-4? ? g/mL and 4? ? g/mL of KA, respectively. Furthermore, the adherence onto S-HAs was inhibited at 3-4? ? g/mL of KA and biofilm formation was significantly inhibited when treated with 3? ? g/mL KA and completely inhibited at 4? ? g/mL. Also, the inhibitory effect of KA on biofilm formation was confirmed by SEM. In confocal laser scanning microscopy, bacterial viability gradually decreased by KA in a dose dependent manner. Real-time PCR analysis showed that the expressions of gtfB, gtfC, gbpB, spaP, brpA, relA, and vicR were significantly decreased in S. mutans when it was treated with KA. These results suggest that KA from A. continentalis may be a useful agent for inhibiting the cariogenic properties of S. mutans. PMID:23662113

Jeong, Seung-Il; Kim, Beom-Su; Keum, Ki-Suk; Lee, Kwang-Hee; Kang, Sun-Young; Park, Bok-Im; Lee, Young-Rae; You, Yong-Ouk

2013-01-01

145

Inhibition of tumor-stromal interaction through HGF/Met signaling by valproic acid  

SciTech Connect

Hepatocyte growth factor (HGF), which is produced by surrounding stromal cells, including fibroblasts and endothelial cells, has been shown to be a significant factor responsible for cancer cell invasion mediated by tumor-stromal interactions. We found in this study that the anti-tumor agent valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, strongly inhibited tumor-stromal interaction. VPA inhibited HGF production in fibroblasts induced by epidermal growth factor (EGF), platelet-derived growth factor, basic fibroblast growth factor, phorbol 12-myristate 13-acetate (PMA) and prostaglandin E{sub 2} without any appreciable cytotoxic effect. Other HDAC inhibitors, including butyric acid and trichostatin A (TSA), showed similar inhibitory effects on HGF production stimulated by various inducers. Up-regulations of HGF gene expression induced by PMA and EGF were also suppressed by VPA and TSA. Furthermore, VPA significantly inhibited HGF-induced invasion of HepG2 hepatocellular carcinoma cells. VPA, however, did not affect the increases in phosphorylation of MAPK and Akt in HGF-treated HepG2 cells. These results demonstrated that VPA inhibited two critical processes of tumor-stromal interaction, induction of fibroblastic HGF production and HGF-induced invasion of HepG2 cells, and suggest that those activities serve for other anti-tumor mechanisms of VPA besides causing proliferation arrest, differentiation, and/or apoptosis of tumor cells.

Matsumoto, Yohsuke; Motoki, Takahiro [Department of Immunochemistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-naka, Okayama 700-8530 (Japan); Kubota, Satoshi; Takigawa, Masaharu [Department of Biochemistry and Molecular Dentistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Shikata-cho, Okayama 700-8525 (Japan); Tsubouchi, Hirohito [Digestive Disease and Life-style Related Disease, Health Research Human and Environmental Sciences, Kagoshima University, Graduate School of Medicine and Dental Sciences, Sakuragaoka, Kagoshima 890-8520 (Japan); Gohda, Eiichi [Department of Immunochemistry, Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1, Tsushima-naka, Okayama 700-8530 (Japan)], E-mail: gohda@pheasant.pharm.okayama-u.ac.jp

2008-02-01

146

Flavonoids apigenin and quercetin inhibit melanoma growth and metastatic potential.  

PubMed

Flavonoids are a class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including chemoprevention and tumor growth inhibition. Our aim was to investigate the effects of several polyphenols on the growth and metastatic potential of B16-BL6 melanoma cells in vivo. Intraperitoneal administration of quercetin, apigenin, (-)-epigallocathechin-3-gallate (EGCG), resveratrol, and the anti-estrogen tamoxifen, at the time of i.m. injection of B16-BL6 cells into syngeneic mice, resulted in a significant, dose-dependent delay of tumor growth, without toxicity. The relative descending order of potency was EGCG > apigenin = quercetin = tamoxifen > resveratrol > control. Furthermore, polyphenols significantly potentiated the inhibitory effect of a non-toxic dose of cisplatin. When tested for the ability to inhibit lung colonization, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the number of B16-BL6 colonies in the lungs in a dose-dependent manner, with quercetin and apigenin being more effective than tamoxifen. Interestingly, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the invasion of B16-BL6 cells in vitro, with quercetin and apigenin being more effective than tamoxifen. This suggests that anti-invasive activity is one of the mechanisms underlying inhibition of lung colonization by quercetin and apigenin. In conclusion, quercetin and apigenin inhibit melanoma growth and invasive and metastatic potential; therefore, they may constitute a valuable tool in the combination therapy of metastatic melanoma. PMID:10918203

Caltagirone, S; Rossi, C; Poggi, A; Ranelletti, F O; Natali, P G; Brunetti, M; Aiello, F B; Piantelli, M

2000-08-15

147

Inhibition of ehrlich mouse ascites tumor growth by cordycepin. Abstr  

Microsoft Academic Search

SUMMARY Cordycepin, a nucleoside isolated from cultures of the mold Cordycepsmilitaris, has been demonstrated to increase the survival time of mice bearing the Ehrlich mouse ascites tumor. In all these studies the drug was administered daily for a 7-day period. AVhendrug inoculations were started the same day as tumor inoculations, inhibition of tumor growth was noted at levels of from

N M Kredich; ARMAND J. GUARINO

1960-01-01

148

Anacardic acid (6-pentadecylsalicylic acid) inhibits tumor angiogenesis by targeting Src/FAK/Rho GTPases signaling pathway.  

PubMed

Anacardic acid (6-pentadecylsalicylic acid), a natural inhibitor of histone acetyltransferase from Amphipterygium adstringens, has been shown to have anti-inflammatory, anticancer, antioxidative, and antimicrobial functions. However, whether this salicylic acid could block angiogenesis has not been elucidated to date. Here, we postulate that anacardic acid affects multiple steps of tumor angiogenesis to contribute to tumor inhibition. In this study, we found that vascular endothelial growth factor (VEGF)-induced cell proliferation, migration, and adhesion and capillary-like structure formation of primary cultured human umbilical vascular endothelial cells (HUVECs) could all be significantly suppressed by anacardic acid in vitro, without detectable cellular toxicity. Furthermore, anacardic acid effectively inhibited vascular development in chick embryo chorioallantoic membrane ex vivo (n = 10) and VEGF-triggered corneal neovascularization in vivo (n = 10). A mechanistic study revealed that anacardic acid blocked activities of Src and FAK kinases in concentration- and time-dependent manners in HUVECs, resulting in activation of RhoA-GTPase and inactivation of Rac1- and Cdc42-GTPases. Of note, when anacardic acid (2 mg/kg per day) was subcutaneously administrated to mice bearing human prostate tumor xenografts (n = 6-7), the volume and weight of solid tumors were significantly retarded. Src, Ki-67, and CD31 immunohistochemical staining further revealed that Src protein expression, tumor cell proliferation, and microvessel density could be remarkably suppressed by anacardic acid. Taken together, our findings demonstrate for the first time that anacardic acid functions as a potent tumor angiogenesis inhibitor by targeting the Src/FAK/Rho GTPase signaling pathway, leading to significant suppression of prostate tumor growth. PMID:21828260

Wu, Yuanyuan; He, Lijun; Zhang, Li; Chen, Jing; Yi, Zhengfang; Zhang, Jian; Liu, Mingyao; Pang, Xiufeng

2011-11-01

149

Provitamin B5 (pantothenol) inhibits growth of the intraerythrocytic malaria parasite.  

PubMed

Pantothenic acid, a precursor of the crucial enzyme cofactor coenzyme A, is one of a relatively few nutrients for which the intraerythrocytic parasite has an absolute and acute requirement from the external medium. In some organisms the provitamin pantothenol can serve as a source of pantothenic acid; however, this was not the case for the human malaria parasite Plasmodium falciparum. Instead, pantothenol inhibited the in vitro growth of P. falciparum via a mechanism that involves competition with pantothenate and which can be attributed to inhibition of the parasite's pantothenate kinase. Oral administration of pantothenol to mice infected with the murine parasite Plasmodium vinckei vinckei resulted in a significant inhibition of parasite proliferation. This study highlights the potential of the coenzyme A biosynthesis pathway in general, and pantothenate kinase in particular, as an antimalarial drug target. PMID:15673744

Saliba, Kevin J; Ferru, Isabelle; Kirk, Kiaran

2005-02-01

150

Provitamin B5 (Pantothenol) Inhibits Growth of the Intraerythrocytic Malaria Parasite  

PubMed Central

Pantothenic acid, a precursor of the crucial enzyme cofactor coenzyme A, is one of a relatively few nutrients for which the intraerythrocytic parasite has an absolute and acute requirement from the external medium. In some organisms the provitamin pantothenol can serve as a source of pantothenic acid; however, this was not the case for the human malaria parasite Plasmodium falciparum. Instead, pantothenol inhibited the in vitro growth of P. falciparum via a mechanism that involves competition with pantothenate and which can be attributed to inhibition of the parasite's pantothenate kinase. Oral administration of pantothenol to mice infected with the murine parasite Plasmodium vinckei vinckei resulted in a significant inhibition of parasite proliferation. This study highlights the potential of the coenzyme A biosynthesis pathway in general, and pantothenate kinase in particular, as an antimalarial drug target. PMID:15673744

Saliba, Kevin J.; Ferru, Isabelle; Kirk, Kiaran

2005-01-01

151

Inhibition of endogenous SPARC enhances pancreatic cancer cell growth: modulation by FGFR1-III isoform expression  

PubMed Central

Background: Secreted protein acidic and rich in cysteine (SPARC) is a multi-faceted protein-modulating cell–cell and cell–matrix interactions. In cancer, SPARC can be not only associated with a highly aggressive phenotype, but also acts as a tumour suppressor. The aim of this study was to characterise the function of SPARC and its modulation by fibroblast growth factor receptor (FGFR) 1 isoforms in pancreatic ductal adenocarcinoma (PDAC). Methods and results: Exogenous SPARC inhibited growth, movement, and migration. ShRNA inhibition of endogenous SPARC in ASPC-1 and PANC-1 cells resulted in increased anchorage-dependent and -independent growth, transwell migration, and xenograft growth as well as increased mitogenic efficacy of fibroblast growth factor (FGF) 1 and FGF2. Endogenous SPARC expression in PANC-1 cells was increased in FGFR1-IIIb over-expressing cells, but decreased in FGFR1-IIIc over-expressing cells. The up-regulation of endogenous SPARC was abrogated by the p38-mitogen-activated protein kinase inhibitor SB203580. SPARC was detectable in conditioned medium of pancreatic stellate cells (PSCs), but not PDAC cells. Conditioned medium of PDAC cells reduced endogenous SPARC expression of PSCs. Conclusion: Endogenous SPARC inhibits the malignant phenotype of PDAC cells and may, therefore, act as a tumour suppressor in PDAC. Endogenous SPARC expression can be modulated by FGFR1-III isoform expression. In addition, PDAC cells may inhibit endogenous SPARC expression in surrounding PSCs by paracrine actions. PMID:19920824

Chen, G; Tian, X; Liu, Z; Zhou, S; Schmidt, B; Henne-Bruns, D; Bachem, M; Kornmann, M

2009-01-01

152

Cyanide inhibits respiration yet stimulates aerobic growth of Zymomonas mobilis.  

PubMed

Potassium cyanide at submillimolar concentrations (20-500 microM) inhibited the high respiration rates of aerobic cultures of Zymomonas mobilis but, remarkably, stimulated culture growth. In batch culture, after an extended lag phase, exponential growth persisted longer, resulting in higher biomass densities. In aerobic chemostat cultures, elevated biomass concentration was observed in the presence of cyanide. This growth stimulation effect is attributed to decreased production of the inhibitory metabolite acetaldehyde at lowered respiration rates, when more reducing equivalents are channelled to alcohol dehydrogenase. Growth in the presence of cyanide did not alter the membrane cytochrome content. In non-growing cyanide-preincubated cells, with ethanol as the respiratory substrate, cyanide increased ATP levels; in such cells, a large part of the cyanide-sensitive respiration was inhibited within a few seconds after ethanol addition, while inhibition of the rest of respiration took several minutes. The more cyanide-sensitive respiration was apparently energy-nongenerating, and was absent in membrane preparations. Pelleting of membranes from cell-free extracts produced 'soluble' fractions in which a b-type haem was detectable by reduced minus oxidized difference spectroscopy. The function of the Z. mobilis respiratory chain in cell growth and respiratory protection, and the possible physiological role of aerobic generation of inhibitory metabolites, are discussed. PMID:10846205

Kalnenieks, U; Galinina, N; Toma, M M; Poole, R K

2000-06-01

153

Inhibition Enzyme Sensor for Nicotine, Nicotinamide and Nicotinic Acid Determination  

NASA Astrophysics Data System (ADS)

Nicotine, nicotinic acid and nicotinamide were tested in pharmaceutical products using an inhibition enzyme sensor consisting of a hydrogen peroxide amperometric electrode coupled to a functionalised nylon membrane chemically bonding the enzymes butyrylcholinesterase and choline oxidase; a butyrylcholine standard solution in glycine buffer acted as substrate.

Campanella, L.; Cocco, R.; Favero, G.; Sammartino, M. P.; Tomassetti, M.

2000-12-01

154

Mycophenolic Acid Inhibits Replication of Japanese Encephalitis Virus  

Microsoft Academic Search

Background: Japanese encephalitis is a major public health problem in several parts of Asia, particularly India, Nepal, Sri Lanka and Myanmar (Burma). Despite its public health implications, there are no effective antiviral drugs available. Methods: The present study evaluated the effect of mycophenolic acid on Japanese encephalitis virus (JEV) using an in vitro cytopathic effect inhibition assay, plaque reduction assay

Liba Sebastian; Shampur Narayan Madhusudana; Vasanthapuram Ravi; Anita Desai

2011-01-01

155

Acid corrosion inhibition of copper by mangrove tannin  

Microsoft Academic Search

Purpose – The purpose of this paper is to evaluate the corrosion inhibition potential of mangrove (Rhizopora apiculata) tannin in hydrochloric acid medium on copper with the view of developing a natural corrosion inhibitor. Design\\/methodology\\/approach – The mangrove tannin was extracted from the mangrove bark and its anticorrosion potential was studied by weight loss, electrochemical and scanning electron microscopy (SEM)

A. M. Shah; A. A. Rahim; S. Yahya; P. B. Raja; S. A. Hamid

2011-01-01

156

A model for multiproduct-inhibited growth of Enterobacter aerogenes in 2,3-butanediol fermentation  

Microsoft Academic Search

Ethanol is identified as a strongly inhibitory metabolite in addition to acetic acid and 2,3-butanediol in 2,3-butanediol production by Enterobacter aerogenes. A model is proposed to describe the multiproduct-inhibited growth of E. aerogenes in 2,3-butanediol fermentation. The model is verified with data from anaerobic and microaerobic continuous culture. On the basis of this model the difference in biomass production and

An-Ping Zeng; Wolf-Dieter Deckwer

1991-01-01

157

Inhibition of Orobanche crenata seed germination and radicle growth by allelochemicals identified in cereals.  

PubMed

Orobanche crenata is a parasitic weed that causes severe yield losses in important grain and forage legume crops. Cereals have been reported to inhibit O. crenata parasitism when grown intercropped with susceptible legumes, but the responsible metabolites have not been identified. A number of metabolites have been reported in cereals that have allelopathic properties against weeds, pests, and pathogens. We tested the effect of several allelochemicals identified in cereals on O. crenata seed germination and radicle development. We found that 2-benzoxazolinone, its derivative 6-chloroacetyl-2-benzoxazolinone, and scopoletin significantly inhibited O. crenata seed germination. Benzoxazolinones, l-tryptophan, and coumalic acid caused the stronger inhibition of radicle growth. Also, other metabolites reduced radicle length, this inhibition being dose-dependent. Only scopoletin caused cell necrotic-like darkening in the young radicles. Prospects for their application to parasitic weed management are discussed. PMID:24044614

Fernández-Aparicio, Mónica; Cimmino, Alessio; Evidente, Antonio; Rubiales, Diego

2013-10-16

158

Syzygium campanulatum korth methanolic extract inhibits angiogenesis and tumor growth in nude mice  

PubMed Central

Background Syzygium campanulatum Korth (Myrtaceae) is an evergreen shrub rich in phenolics, flavonoid antioxidants, and betulinic acid. This study sought to investigate antiangiogenic and anti-colon cancer effects of S.C. standardized methanolic extract. Methods Betulinic acid was isolated from methanolic extract by crystallization and chromatography techniques. S.C. methanolic extract was analyzed by UV-Vis spectrophotometry, FTIR, LC-MS, and HPLC. Antiangiogenic effect was studied on rat aortic rings, matrigel tube formation, cell proliferation and migration, and expression of vascular endothelial growth factor (VEGF). Antitumor effect was studied using a subcutaneous tumor model of HCT 116 colorectal carcinoma cells established in nude mice. Results Analysis by HPLC, LC-MS and FTIR confirm presence of betulinic acid in S.C. methanolic extract. Quantitative analysis by HPLC indicates presence of betulinic acid in S.C. extract at 5.42?±?0.09% (w/w). Antiangiogenesis study showed potent inhibition of microvessels outgrowth in rat aortic rings, and studies on normal and cancer cells did not show any significant cytotoxic effect. Antiangiogenic effect was further confirmed by inhibition of tube formation on matrigel matrix that involves human endothelial cells (IC50?=?17.6?±?2.9 ?g/ml). S.C. extract also inhibited migration of endothelial cells and suppressed expression of VEGF. In vivo antiangiogenic study showed inhibition of new blood vessels in chicken embryo chorioallantoic membrane (CAM), and in vivo antitumor study showed significant inhibition of tumor growth due to reduction of intratumor blood vessels and induction of cell death. Conclusion Collectively, our results indicate S. campanulatum as antiangiogenic and antitumor candidate, and a new source of betulinic acid. PMID:23842450

2013-01-01

159

Zoledronic acid inhibits pulmonary metastasis dissemination in a preclinical model of Ewing's sarcoma via inhibition of cell migration  

PubMed Central

Background Ewing’s sarcoma (ES) is the second most frequent primitive malignant bone tumor in adolescents with a very poor prognosis for high risk patients, mainly when lung metastases are detected (overall survival <15% at 5 years). Zoledronic acid (ZA) is a potent inhibitor of bone resorption which induces osteoclast apoptosis. Our previous studies showed a strong therapeutic potential of ZA as it inhibits ES cell growth in vitro and ES primary tumor growth in vivo in a mouse model developed in bone site. However, no data are available on lung metastasis. Therefore, the aim of this study was to determine the effect of ZA on ES cell invasion and metastatic properties. Methods Invasion assays were performed in vitro in Boyden’s chambers covered with Matrigel. Matrix Metalloproteinase (MMP) activity was analyzed by zymography in ES cell culture supernatant. In vivo, a relevant model of spontaneous lung metastases which disseminate from primary ES tumor was induced by the orthotopic injection of 106 human ES cells in the tibia medullar cavity of nude mice. The effect of ZA (50 ?g/kg, 3x/week) was studied over a 4-week period. Lung metastases were observed macroscopically at autopsy and analysed by histology. Results ZA induced a strong inhibition of ES cell invasion, probably due to down regulation of MMP-2 and ?9 activities as analyzed by zymography. In vivo, ZA inhibits the dissemination of spontaneous lung metastases from a primary ES tumor but had no effect on the growth of established lung metastases. Conclusion These results suggest that ZA could be used early in the treatment of ES to inhibit bone tumor growth but also to prevent the early metastatic events to the lungs. PMID:24612486

2014-01-01

160

Stereocomplexes Formed From Select Oligomers of Polymer d-lactic Acid (PDLA) and l-lactate May Inhibit Growth of Cancer Cells and Help Diagnose Aggressive Cancers--Applications of the Warburg Effect  

PubMed Central

It is proposed that select oligomers of polymer d-lactic acid (PDLA) will form a stereocomplex with l-lactate in vivo, producing lactate deficiency in tumor cells. Those cancer cells that utilize transport of lactate to maintain electrical neutrality may cease to multiply or die because of lactate trapping, and those cancer cells that benefit from utilization of extracellular lactate may be impaired. Intracellular trapping of lactate produces a different physiology than inhibition of LDH because the cell loses the option of shuttling pyruvate to an alternative pathway to produce an anion. Conjugated with stains or fluorescent probes, PDLA oligomers may be an agent for the diagnosis of tissue lactate and possibly cell differentiation in biopsy specimens. Preliminary experimental evidence is presented confirming that PDLA in high concentrations is cytotoxic and that l-lactate forms a presumed stereocomplex with PDLA. Future work should be directed at isolation of biologically active oligomers of PDLA. PMID:21487535

Goldberg, Joel S.

2011-01-01

161

Gradient microfluidics enables rapid bacterial growth inhibition testing.  

PubMed

Bacterial growth inhibition tests have become a standard measure of the adverse effects of inhibitors for a wide range of applications, such as toxicity testing in the medical and environmental sciences. However, conventional well-plate formats for these tests are laborious and provide limited information (often being restricted to an end-point assay). In this study, we have developed a microfluidic system that enables fast quantification of the effect of an inhibitor on bacteria growth and survival, within a single experiment. This format offers a unique combination of advantages, including long-term continuous flow culture, generation of concentration gradients, and single cell morphology tracking. Using Escherichia coli and the inhibitor amoxicillin as one model system, we show excellent agreement between an on-chip single cell-based assay and conventional methods to obtain quantitative measures of antibiotic inhibition (for example, minimum inhibition concentration). Furthermore, we show that our methods can provide additional information, over and above that of the standard well-plate assay, including kinetic information on growth inhibition and measurements of bacterial morphological dynamics over a wide range of inhibitor concentrations. Finally, using a second model system, we show that this chip-based systems does not require the bacteria to be labeled and is well suited for the study of naturally occurring species. We illustrate this using Nitrosomonas europaea, an environmentally important bacteria, and show that the chip system can lead to a significant reduction in the period required for growth and inhibition measurements (<4 days, compared to weeks in a culture flask). PMID:24548044

Li, Bing; Qiu, Yong; Glidle, Andrew; McIlvenna, David; Luo, Qian; Cooper, Jon; Shi, Han-Chang; Yin, Huabing

2014-03-18

162

An interfacial energy mechanism for the complete inhibition of crystal growth by inhibitor adsorption  

E-print Network

An interfacial energy mechanism for the complete inhibition of crystal growth by inhibitor for complete crystal-growth inhibition based on the thermodynamics of interfaces. The premise for our model or to a reduction in growth rate. The inhibition of crystal growth due to adsorption is impor- tant for both natural

Firoozabadi, Abbas

163

Inhibition of gingival fibroblast growth by Bacteroides gingivalis.  

PubMed Central

Human gingival fibroblasts were exposed in culture to cell extracts of different black-pigmented Bacteroides species, and their growth was monitored by determining thymidine uptake and counting cells. Of the Bacteroides species tested (B. gingivalis, B. asaccharolyticus, and B. intermedius), B. gingivalis gave the extract with the strongest inhibitory effect on fibroblast thymidine uptake. Linear inhibition reaching 80% of the control level was obtained with a dose of 100 micrograms of B. gingivalis extract protein per ml. The effect of B. asaccharolyticus resembled that of B. gingivalis, but even at the highest dose tested B. intermedius had only a slight inhibitory effect. When fibroblasts were counted after 2- and 4-day exposures to B. gingivalis extracts, a clear depression in the number of fibroblasts was found. The effects of extracts obtained from early and late growth phases of B. gingivalis cultures were similar. A fraction of B. gingivalis consisting essentially of lipopolysaccharides (LPSs) was obtained by degrading the extract proteins with proteinase K. Silver staining of polyacrylamide gels revealed a LPS pattern with a molecular mass ranging from 37 to 60 kilodaltons. This LPS-rich fraction caused inhibition of thymidine uptake by gingival fibroblasts similar to that caused by the native extract alone. Thus, the inhibition of gingival fibroblast growth by B. gingivalis appeared to be LPS mediated. This inhibitory effect of B. gingivalis on oral fibroblast growth may be a virulence factor of this bacterium. Images PMID:3793230

Larjava, H; Uitto, V J; Eerola, E; Haapasalo, M

1987-01-01

164

Apicoplast-Targeting Antibacterials Inhibit the Growth of Babesia Parasites  

PubMed Central

The apicoplast housekeeping machinery, specifically apicoplast DNA replication, transcription, and translation, was targeted by ciprofloxacin, thiostrepton, and rifampin, respectively, in the in vitro cultures of four Babesia species. Furthermore, the in vivo effect of thiostrepton on the growth cycle of Babesia microti in BALB/c mice was evaluated. The drugs caused significant inhibition of growth from an initial parasitemia of 1% for Babesia bovis, with 50% inhibitory concentrations (IC50s) of 8.3, 11.5, 12, and 126.6 ?M for ciprofloxacin, thiostrepton, rifampin, and clindamycin, respectively. The IC50s for the inhibition of Babesia bigemina growth were 15.8 ?M for ciprofloxacin, 8.2 ?M for thiostrepton, 8.3 ?M for rifampin, and 206 ?M for clindamycin. The IC50s for Babesia caballi were 2.7 ?M for ciprofloxacin, 2.7 ?M for thiostrepton, 4.7 ?M for rifampin, and 4.7 ?M for clindamycin. The IC50s for the inhibition of Babesia equi growth were 2.5 ?M for ciprofloxacin, 6.4 ?M for thiostrepton, 4.1 ?M for rifampin, and 27.2 ?M for clindamycin. Furthermore, an inhibitory effect was revealed for cultures with an initial parasitemia of either 10 or 7% for Babesia bovis or Babesia bigemina, respectively. The three inhibitors caused immediate death of Babesia bovis and Babesia equi. The inhibitory effects of ciprofloxacin, thiostrepton, and rifampin were confirmed by reverse transcription-PCR. Thiostrepton at a dose of 500 mg/kg of body weight resulted in 77.5% inhibition of Babesia microti growth in BALB/c mice. These results implicate the apicoplast as a potential chemotherapeutic target for babesiosis. PMID:22391527

AbouLaila, Mahmoud; Munkhjargal, Tserendorj; Sivakumar, Thillaiampalam; Ueno, Akio; Nakano, Yuki; Yokoyama, Miki; Yoshinari, Takeshi; Nagano, Daisuke; Katayama, Koji; El-Bahy, Nasr; Yokoyama, Naoaki

2012-01-01

165

Proteasome inhibition by fellutamide B induces nerve growth factor synthesis.  

PubMed

Neurotrophic small molecules have the potential to aid in the treatment of neuronal injury and neurodegenerative diseases. The natural product fellutamide B, originally isolated from Penicillium fellutanum, potently induces nerve growth factor (NGF) release from fibroblasts and glial-derived cells, although the mechanism for this neurotrophic activity has not been elucidated. Here, we report that fellutamide B potently inhibits proteasome catalytic activity. High-resolution structural information obtained from cocrystallization of the 20S proteasome reveals novel aspects regarding beta-subunit binding and adduct formation by fellutamide B to inhibit their hydrolytic activity. We demonstrate that fellutamide B and other proteasome inhibitors increased NGF gene transcription via a cis-acting element (or elements) in the promoter. These results demonstrate an unrecognized connection between proteasome inhibition and NGF production, suggesting a possible new strategy in the development of neurotrophic agents. PMID:18482702

Hines, John; Groll, Michael; Fahnestock, Margaret; Crews, Craig M

2008-05-01

166

Proteasome Inhibition by Fellutamide B Induces Nerve Growth Factor Synthesis  

PubMed Central

SUMMARY Neurotrophic small molecules have the potential to aid in the treatment of neuronal injury and neurodegenerative diseases. The natural product fellutamide B, originally isolated from Penicillium fellutanum, potently induces nerve growth factor (NGF) release from fibroblasts and glial-derived cells, although the mechanism for this neurotrophic activity has not been elucidated. Here, we report that fellutamide B potently inhibits proteasome catalytic activity. High resolution structural information obtained from co-crystallization of the 20S proteasome reveals novel aspects regarding ?-subunit binding and adduct formation by fellutamide B to inhibit their hydrolytic activity. We demonstrate that fellutamide B and other proteasome inhibitors increased NGF gene transcription via a cis-acting element (or elements) in the promoter. These results demonstrate an unrecognized connection between proteasome inhibition and NGF production, suggesting a possible new strategy in the development of neurotrophic agents. PMID:18482702

Hines, John; Groll, Michael; Fahnestock, Margaret; Crews, Craig M.

2008-01-01

167

Effect of organic acids on the growth and fermentation of ethanologenic Escherichia coli LY01.  

PubMed

Hemicellulose residues can be hydrolyzed into a sugar syrup using dilute mineral acids. Although this syrup represents a potential feedstock for biofuel production, toxic compounds generated during hydrolysis limit microbial metabolism. Escherichia coli LY01, an ethanologenic biocatalyst engineered to ferment the mixed sugars in hemicellulose syrups, has been tested for resistance to selected organic acids that are present in hemicellulose hydrolysates. Compounds tested include aromatic acids derived from lignin (ferulic, gallic, 4-hydroxybenzoic, syringic, and vanillic acids), acetic acid from the hydrolysis of acetylxylan, and others derived from sugar destruction (furoic, formic, levulinic, and caproic acids). Toxicity was related to hydrophobicity. Combinations of acids were roughly additive as inhibitors of cell growth. When tested at concentrations that inhibited growth by 80%, none appeared to strongly inhibit glycolysis and energy generation, or to disrupt membrane integrity. Toxicity was not markedly affected by inoculum size or incubation temperature. The toxicity of all acids except gallic acid was reduced by an increase in initial pH (from pH 6.0 to pH 7.0 to pH 8.0). Together, these results are consistent with the hypothesis that both aliphatic and mononuclear organic acids inhibit growth and ethanol production in LY01 by collapsing ion gradients and increasing internal anion concentrations. PMID:10578090

Zaldivar, J; Ingram, L O

1999-01-01

168

Effect of organic acids on the growth and fermentation of ethanologenic Escherichia coli LY01  

SciTech Connect

Hemicellulose residues can be hydrolyzed into a sugar syrup using dilute mineral acids. Although this syrup represents a potential feedstock for biofuel production, toxic compounds generated during hydrolysis limit microbial metabolism. Escherichia coli LY01, an ethanologenic biocatalyst engineered to ferment the mixed sugars in hemicellulose syrups, has been tested for resistance to selected organic acids that re present in hemicellulose hydrolysates. Compounds tested include aromatic acids derived from lignin (ferulic, gallic, 4-hydroxybenzoic, syringic, and vanillic acids), acetic acid from the hydrolysis of acetylxylan, and others derived from sugar destruction (furoic, formic, levulinic, and caproic acids). Toxicity was related to hydrophobicity. Combinations of acids were roughly additive as inhibitors of cell growth. When tested at concentrations that inhibited growth by 80%, none appeared to strongly inhibit glycolysis and energy generation, or to disrupt membrane integrity. Toxicity was not markedly affected by inoculum size or incubation temperature. The toxicity of all acids except gallic acid was reduced by an increase in initial pH (from pH 6.0 to pH 7.0 to pH 8.0). Together, these results are consistent with the hypothesis that both aliphatic and mononuclear organic acids inhibit growth and ethanol production in LY01 by collapsing ion gradients and increasing internal anion concentrations.

Zaldivar, J.; Ingram, L.O.

1999-07-01

169

Vasostatin, a Calreticulin Fragment, Inhibits Angiogenesis and Suppresses Tumor Growth  

Microsoft Academic Search

Summary An endothelial cell inhibitor was purified from supernatant of an Epstein-Barr virus-immortal- ized cell line and identified as fragments of calreticulin. The purified recombinant NH 2 -termi- nal domain of calreticulin (amino acids 1-180) inhibited the proliferation of endothelial cells, but not cells of other lineages, and suppressed angiogenesis in vivo. We have named this NH 2 - terminal

Sandra E. Pike; Lei Yao; Karen D. Jones; Barry Cherney; Ettore Appella; Kazuyasu Sakaguchi; Hira Nakhasi; Julie Teruya-Feldstein; Peter Wirth; Ghanshyam Gupta; Giovanna Tosato

2010-01-01

170

Growth Inhibition of Pathogenic Bacteria by Sulfonylurea Herbicides  

PubMed Central

Emerging resistance to current antibiotics raises the need for new microbial drug targets. We show that targeting branched-chain amino acid (BCAA) biosynthesis using sulfonylurea herbicides, which inhibit the BCAA biosynthetic enzyme acetohydroxyacid synthase (AHAS), can exert bacteriostatic effects on several pathogenic bacteria, including Burkholderia pseudomallei, Pseudomonas aeruginosa, and Acinetobacter baumannii. Our results suggest that targeting biosynthetic enzymes like AHAS, which are lacking in humans, could represent a promising antimicrobial drug strategy. PMID:23263008

Kreisberg, Jason F.; Ong, Nicholas T.; Krishna, Aishwarya; Joseph, Thomas L.; Wang, Jing; Ong, Catherine; Ooi, Hui Ann; Sung, Julie C.; Siew, Chern Chiang; Chang, Grace C.; Biot, Fabrice; Cuccui, Jon; Wren, Brendan W.; Chan, Joey; Sivalingam, Suppiah P.; Zhang, Lian-Hui; Verma, Chandra

2013-01-01

171

Growth inhibition of hopanoid synthesizing bacteria by squalene cyclase inhibitors  

Microsoft Academic Search

2,3-Dihydro-2-azasqualene, its N-oxide and its N,N-diethyl analogue, as well as 2,3-dihydro-2,3-iminosqualene are potent inhibitors of the squalene to hopanoid (diplotene and diplopterol) cyclases in cell-free systems from Acetobacter pasteurianus ssp pasteurianus, Methylobacterium organophilum and Zymomonas mobilis. The inhibitory concentration giving 50% inhibition at a 120 µM squalene concentration was determined in each cases. The growth of hopanoid producing prokaryotes (with

G. Flesch; M. Rohmer

1987-01-01

172

Inhibition of Mycobacterial Alanine Racemase Activity and Growth by Thiadiazolidinones  

PubMed Central

The genus Mycobacterium includes non-pathogenic species such as M. smegmatis, and pathogenic species such as M. tuberculosis, the causative agent of tuberculosis (TB). Treatment of TB requires a lengthy regimen of several antibiotics, whose effectiveness has been compromised by the emergence of resistant strains. New antibiotics that can shorten the treatment course and those that have not been compromised by bacterial resistance are needed. In this study, we report that thiadiazolidinones, a relatively little-studied heterocyclic class, inhibit the activity of mycobacterial alanine racemase, an essential enzyme that converts L-alanine to D-alanine for peptidoglycan synthesis. Twelve members of the thiadiazolidinone family were evaluated for inhibition of M. tuberculosis and M. smegmatis alanine racemase activity and bacterial growth. Thiadiazolidinones inhibited M. tuberculosis and M. smegmatis alanine racemases to different extents with 50% inhibitory concentrations (IC50) ranging from <0.03 to 28 µM and 23 to >150 µM, respectively. The compounds also inhibited the growth of these bacteria, including multidrug resistant strains of M. tuberculosis. The minimal inhibitory concentrations (MIC) for drug-susceptible M. tuberculosis and M. smegmatis ranged from 6.25 µg/ml to 100 µg/ml, and from 1.56 to 6.25 µg/ml for drug-resistant M. tuberculosis. The in vitro activities of thiadiazolidinones suggest that this family of compounds might represent starting points for medicinal chemistry efforts aimed at developing novel antimycobacterial agents. PMID:23680030

Lee, Yashang; Mootien, Sara; Shoen, Carolyn; Destefano, Michelle; Cirillo, Pier; Asojo, Oluwatoyin A.; Yeung, Kacheong R.; Ledizet, Michel; Cynamon, Michael H.; Aristoff, Paul A.; Koski, Raymond A.; Kaplan, Paul A.; Anthony, Karen G.

2013-01-01

173

Tumor suppressor XAF1 induces apoptosis, inhibits angiogenesis and inhibits tumor growth in hepatocellular carcinoma  

PubMed Central

X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1), a XIAP-binding protein, is a tumor suppressor gene. XAF1 was silent or expressed lowly in most human malignant tumors. However, the role of XAF1 in hepatocellular carcinoma (HCC) remains unknown. In this study, we investigated the effect of XAF1 on tumor growth and angiogenesis in hepatocellular cancer cells. Our results showed that XAF1 expression was lower in HCC cell lines SMMC-7721, Hep G2 and BEL-7404 and liver cancer tissues than that in paired non-cancer liver tissues. Adenovirus-mediated XAF1 expression (Ad5/F35-XAF1) significantly inhibited cell proliferation and induced apoptosis in HCC cells in dose- and time- dependent manners. Infection of Ad5/F35-XAF1 induced cleavage of caspase -3, -8, -9 and PARP in HCC cells. Furthermore, Ad5/F35-XAF1 treatment significantly suppressed tumor growth in a xenograft model of liver cancer cells. Western Blot and immunohistochemistry staining showed that Ad5/F35-XAF1 treatment suppressed expression of vascular endothelial growth factor (VEGF), which is associated with tumor angiogenesis, in cancer cells and xenograft tumor tissues. Moreover, Ad5/F35-XAF1 treatment prolonged the survival of tumor-bearing mice. Our results demonstrate that XAF1 inhibits tumor growth by inducing apoptosis and inhibiting tumor angiogenesis. XAF1 may be a promising target for liver cancer treatment. PMID:24980821

Zhu, Li Ming; Shi, Dong Mei; Dai, Qiang; Cheng, Xiao Jiao; Yao, Wei Yan; Sun, Ping Hu; Ding, Yan Fei; Qiao, Min Min; Wu, Yun Lin; Jiang, Shi Hu; Tu, Shui Ping

2014-01-01

174

Formulation Design of Acidic Fibroblast Growth Factor  

Microsoft Academic Search

The design of an aqueous formulation for acidic fibroblast growth factor (aFGF) requires an understanding of the type of compounds that can either directly or indirectly stabilize the protein. To this end, spectrophotometric turbidity measurements were initially employed to screen the ability of polyanionic ligands, less specific compounds, and variations in solution conditions (temperature and pH) to stabilize aFGF against

P. K. Tsai; David B. Volkin; Jonathan M. Dabora; Karen C. Thompson; Mark W. Bruner; Jacqueline O. Gress; Bozena Matuszewska; Martina Keogan; Joseph V. Bondi; C. Russell Middaugh

1993-01-01

175

Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid.  

PubMed

Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is -0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol(-1). Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization. PMID:23692683

Lidong, Wang; Yongliang, Ma; Wendi, Zhang; Qiangwei, Li; Yi, Zhao; Zhanchao, Zhang

2013-08-15

176

Fn14•Trail Effectively Inhibits Hepatocellular Carcinoma Growth  

PubMed Central

Background New strategies for the treatment of hepatocellular carcinoma (HCC) are needed, given that currently available chemotherapeutics are inefficient. Since tumor growth reflects the net balance between pro-proliferative and death signaling, agents shifting the equilibrium toward the latter are of considerable interest. The TWEAK:Fn14 signaling axis promotes tumor cell proliferation and tumor angiogenesis, while TRAIL:TRAIL-receptor (TRAIL-R) interactions selectively induce apoptosis in malignant cells. Fn14•TRAIL, a fusion protein bridging these two pathways, has the potential to inhibit tumor growth, by interfering with TWEAK:Fn14 signaling, while at the same time enforcing TRAIL:TRAIL-R-mediated apoptosis. Consequently, Fn14•TRAIL's capacity to inhibit HCC growth was tested. Results Fn14•TRAIL induced robust apoptosis of multiple HCC cell lines, while sparing non-malignant hepatocyte cell lines. Differential susceptibility to this agent did not correlate with expression levels of TRAIL, TRAIL-R, TWEAK and Fn14 by these lines. Fn14•TRAIL was more potent than soluble TRAIL, soluble Fn14, or a combination of the two. The requirement of both of Fn14•TRAIL's molecular domains for function was established using blocking antibodies directed against each of them. Subcutaneous injection of Fn14•TRAIL abrogated HCC growth in a xenograft model, and was well tolerated by the mice. Conclusions In this study, Fn14•TRAIL, a multifunctional fusion protein originally designed to treat autoimmunity, was shown to inhibit the growth of HCC, both in vitro and in vivo. The demonstration of this fusion protein’s potent anti-tumor activity suggests that simultaneous targeting of two signaling axes by a single fusion can serve as a basis for highly effective anti-cancer therapies. PMID:24130833

Aronin, Alexandra; Amsili, Shira; Prigozhina, Tatyana B.; Tzdaka, Kobi; Rachmilewitz, Jacob; Shani, Noam; Tykocinski, Mark L.; Dranitzki Elhalel, Michal

2013-01-01

177

Effects of abscisic acid on growth and dehydration tolerance of Cynanchum komarovii seedlings  

Microsoft Academic Search

Cynanchum komarovii is well adapted to hot and dry adverse environments. To determine if exogenous abscisic acid (ABA) affects the growth and\\u000a dehydration tolerance of this wild plant, ABA was added into the hydroponic solution at a final concentration of 10 ?M for\\u000a 14 days. Root growth is less inhibited than shoot growth under well-watered condition by ABA treatment. ABA reduced

L. Yang; C. L. Yu; F. Shi; Y. Q. Wei; C. C. Wang; H. T. Hu; C. G. Cheng

2007-01-01

178

Inhibition of experimental autoimmune uveitis by amino acid copolymers  

Microsoft Academic Search

Glatiramer acetate (GA), a synthetic random amino acid copolymer, poly(Y, E, A, K)n, is widely used for treatment of multiple sclerosis. It inhibits experimental autoimmune encephalomyelitis (EAE) in mice by competition with the antigen and by induction of regulatory T cells. A novel copolymer, poly (F, Y, A, K)n , designated FYAK, was more effective than GA in its immunomodulatory

Hongen Yin; Barbara P. Vistica; Chi-Chao Chan; Jack L. Strominger; Igal Gery

2009-01-01

179

The inhibition of calcium carbonate crystal growth by the cysteine-rich Mdm2 peptide.  

PubMed

The crystal growth of calcite, the most stable calcium carbonate polymorph, in the presence of the cysteine-rich Mdm2 peptide (containing 48 amino acids in the ring finger configuration), has been investigated by the constant composition technique. Crystallization took place exclusively on well-characterized calcite crystals in solutions supersaturated only with respect to this calcium carbonate salt. The kinetic results indicated a surface diffusion spiral growth mechanism. The presence of the Mdm2 peptide inhibited the crystal growth of calcite by 22-58% in the concentration range tested, through adsorption onto the active growth sites of the calcite crystal surface. The kinetic results favored a Langmuir-type adsorption model, and the value of the calculated affinity constant was k(aff)=147x10(4) dm(3)mol(-1), a(ads)=0.29. PMID:16678843

Dalas, E; Chalias, A; Gatos, D; Barlos, K

2006-08-15

180

Studies of the effect of gibberellic acid on algal growth.  

NASA Technical Reports Server (NTRS)

The effect of gibberellic acid on exponential growth rate of four strains of Chlorella was investigated under variety of experimental conditions. In concentrations from 10 ppm to 100 ppm, gibberellic acid was shown to have no effect on Chlorella growth. In concentration of 200 ppm, gibberellic acid exerted some unfavorable effect on algal growth.

Evans, W. K.; Sorokin, C.

1971-01-01

181

Growth Inhibition After Exposure to Transforming Growth Factor-?1 in Human Bladder Cancer Cell Lines  

PubMed Central

Purpose Transforming growth factor-?1 (TGF-?1) plays a dual role in apoptosis and in proapoptotic responses in the support of survival in a variety of cells. The aim of this study was to determine the function of TGF-?1 in bladder cancer cells. Materials and Methods The role of TGF-?1 in bladder cancer cells was examined by observing cell viability by using the tetrazolium dye (MTT) assay after treating the bladder cancer cell lines 253J, 5637, T24, J82, HT1197, and HT1376 with TGF-?1. Among these cell lines, the 253J and T24 cell lines were coincubated with TGF-?1 and the pan anti-TGF-? antibody. Fluorescence-activated cell sorter (FACS) analysis was performed to determine the mechanism involved after TGF-?1 treatment in 253J cells. Results All six cell lines showed inhibited cellular growth after TGF-?1 treatment. Although the T24 and J82 cell lines also showed inhibited cellular growth, the growth inhibition was less than that observed in the other 4 cell lines. The addition of pan anti-TGF-? antibodies to the culture media restored the growth properties that had been inhibited by TGF-?1. FACS analysis was performed in the 253J cells and the 253J cells with TGF-?1. There were no significant differences in the cell cycle between the two treatments. However, there were more apoptotic cells in the TGF-?1-treated 253J cells. Conclusions TGF-?1 did not stimulate cellular proliferation but was a growth inhibitory factor in bladder cancer cells. However, the pattern of its effects depended on the cell line. TGF-?1 achieved growth inhibition by enhancing the level of apoptosis. PMID:25045449

Lee, Changho; Lee, Sang-Han; Kim, Doo Sang; Jeon, Yun Soo; Lee, Nam Kyu

2014-01-01

182

Effect of fatty acids on the mycelial growth and polysaccharide formation by Ganoderma lucidum in shake flask cultures  

Microsoft Academic Search

Fatty acids were added into the media to investigate their effects on the mycelial growth and polysaccharide formation by Ganoderma lucidum. The experiments were carried out in freely suspended cultures or immobilized cultures using shake flasks. The results indicate that the extent of stimulation or inhibition were associated with the types and levels of fatty acids. Oleic acid at the

Fan-Chiang Yang; Yn-Fuu Ke; Shanq-Shin Kuo

2000-01-01

183

The non-metabolizable glucose analog D-glucal inhibits aflatoxin biosynthesis and promotes kojic acid production in Aspergillus flavus  

PubMed Central

Background Aflatoxins (AFs) are potent carcinogenic compounds produced by several Aspergillus species, which pose serious threats to human health. As sugar is a preferred carbohydrate source for AF production, we examined the possibility of using sugar analogs to inhibit AF biosynthesis. Results We showed that although D-glucal cannot be utilized by A. flavus as the sole carbohydrate source, it inhibited AF biosynthesis and promoted kojic acid production without affecting mycelial growth when applied to a glucose-containing medium. The inhibition occurred before the production of the first stable intermediate, norsolorinic acid, suggesting a complete inhibition of the AF biosynthetic pathway. Further studies showed that exogenous D-glucal in culture led to reduced accumulation of tricarboxylic acid (TCA) cycle intermediates and reduced glucose consumption, indicating that glycolysis is inhibited. Expression analyses revealed that D-glucal suppressed the expression of AF biosynthetic genes but promoted the expression of kojic acid biosynthetic genes. Conclusions D-glucal as a non-metabolizable glucose analog inhibits the AF biosynthesis pathway by suppressing the expression of AF biosynthetic genes. The inhibition may occur either directly through interfering with glycolysis, or indirectly through reduced oxidative stresses from kojic acid biosynthesis. PMID:24742119

2014-01-01

184

Inhibition by caffeic acid of the influenza A virus multiplication in vitro.  

PubMed

Caffeic acid has been shown to inhibit the multiplication of influenza A virus in vitro, whereas caffeine, quinic acid and chlorogenic acid do not. Caffeic acid has also been shown to have antiviral activity against herpes simplex virus (DNA virus) and polio virus (RNA virus). In the present study, a comparison of the one-step growth curve of the influenza virus in the presence of caffeic acid with that in the absence of the reagent showed that an eclipse period of the virus multiplication in the infected cells was not affected by the reagent, while the progeny virus yield was markedly decreased in the presence of caffeic acid. In additional experiments, it was found that the addition of caffeic acid at an early time point post-infection (within 3 h post-infection) was mandatory for extensive antiviral activity, suggesting that a major target of the reagent exists in the early stages of infection. Simultaneously with the decrease in the progeny virus yield, both the virus-induced cytopathic effects and apoptotic nuclear fragmentation were markedly suppressed by the reagent, suggesting that caffeic acid suppresses, at least temporally, the degeneration of the virus-infected cells and that the observed antiviral activity is likely not the secondary result of the cytotoxic effects of the reagent. These results suggest the potential pharmacological use of caffeic acid or its derivatives as an antiviral drug against influenza A virus. PMID:25050906

Utsunomiya, Hirotoshi; Ichinose, Masao; Ikeda, Keiko; Uozaki, Misao; Morishita, Junko; Kuwahara, Tomomi; Koyama, A Hajime; Yamasaki, Hisashi

2014-10-01

185

Cadmium inhibits acid secretion in stimulated frog gastric mucosa  

SciTech Connect

Cadmium, a toxic environmental pollutant, affects the function of different organs such as lungs, liver and kidney. Less is known about its toxic effects on the gastric mucosa. The aim of this study was to investigate the mechanisms by which cadmium impacts on the physiology of gastric mucosa. To this end, intact amphibian mucosae were mounted in Ussing chambers and the rate of acid secretion, short circuit current (I{sub sc}), transepithelial potential (V{sub t}) and resistance (R{sub t}) were recorded in the continuous presence of cadmium. Addition of cadmium (20 {mu}M to 1 mM) on the serosal but not luminal side of the mucosae resulted in inhibition of acid secretion and increase in NPPB-sensitive, chloride-dependent short circuit current. Remarkably, cadmium exerted its effects only on histamine-stimulated tissues. Experiments with TPEN, a cell-permeant chelator for heavy metals, showed that cadmium acts from the intracellular side of the acid secreting cells. Furthermore, cadmium-induced inhibition of acid secretion and increase in I{sub sc} cannot be explained by an action on: 1) H{sub 2} histamine receptor, 2) Ca{sup 2+} signalling 3) adenylyl cyclase or 4) carbonic anhydrase. Conversely, cadmium was ineffective in the presence of the H{sup +}/K{sup +}-ATPase blocker omeprazole suggesting that the two compounds likely act on the same target. Our findings suggest that cadmium affects the functionality of histamine-stimulated gastric mucosa by inhibiting the H{sup +}/K{sup +}-ATPase from the intracellular side. These data shed new light on the toxic effect of this dangerous environmental pollutant and may result in new avenues for therapeutic intervention in acute and chronic intoxication.

Gerbino, Andrea, E-mail: gerbino@biologia.uniba.i [Dept. of General and Environmental Physiology, University of Bari, 70126 Bari (Italy); Debellis, Lucantonio; Caroppo, Rosa [Dept. of General and Environmental Physiology, University of Bari, 70126 Bari (Italy); Curci, Silvana [VA Boston Healthcare System and the Department of Surgery, Harvard Medical School, and Brigham and Women's Hospital, 1400 VFW Parkway, West Roxbury MA 02132 (United States); Colella, Matilde [Dept. of General and Environmental Physiology, University of Bari, 70126 Bari (Italy)

2010-06-01

186

Antigen 85C inhibition restricts Mycobacterium tuberculosis growth through disruption of cord factor biosynthesis.  

PubMed

The antigen 85 (Ag85) protein family, consisting of Ag85A, -B, and -C, is vital for Mycobacterium tuberculosis due to its role in cell envelope biogenesis. The mycoloyl transferase activity of these proteins generates trehalose dimycolate (TDM), an envelope lipid essential for M. tuberculosis virulence, and cell wall arabinogalactan-linked mycolic acids. Inhibition of these enzymes through substrate analogs hinders growth of mycobacteria, but a link to mycolic acid synthesis has not been established. In this study, we characterized a novel inhibitor of Ag85C, 2-amino-6-propyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile (I3-AG85). I3-AG85 was isolated from a panel of four inhibitors that exhibited structure- and dose-dependent inhibition of M. tuberculosis division in broth culture. I3-AG85 also inhibited M. tuberculosis survival in infected primary macrophages. Importantly, it displayed an identical MIC against the drug-susceptible H37Rv reference strain and a panel of extensively drug-resistant/multidrug-resistant M. tuberculosis strains. Nuclear magnetic resonance analysis indicated binding of I3-AG85 to Ag85C, similar to its binding to the artificial substrate octylthioglucoside. Quantification of mycolic acid-linked lipids of the M. tuberculosis envelope showed a specific blockade of TDM synthesis. This was accompanied by accumulation of trehalose monomycolate, while the overall mycolic acid abundance remained unchanged. Inhibition of Ag85C activity also disrupted the integrity of the M. tuberculosis envelope. I3-AG85 inhibited the division of and reduced TDM synthesis in an M. tuberculosis strain deficient in Ag85C. Our results indicate that Ag85 proteins are promising targets for novel antimycobacterial drug design. PMID:22290959

Warrier, Thulasi; Tropis, Marielle; Werngren, Jim; Diehl, Anne; Gengenbacher, Martin; Schlegel, Brigitte; Schade, Markus; Oschkinat, Hartmut; Daffe, Mamadou; Hoffner, Sven; Eddine, Ali Nasser; Kaufmann, Stefan H E

2012-04-01

187

Antigen 85C Inhibition Restricts Mycobacterium tuberculosis Growth through Disruption of Cord Factor Biosynthesis  

PubMed Central

The antigen 85 (Ag85) protein family, consisting of Ag85A, -B, and -C, is vital for Mycobacterium tuberculosis due to its role in cell envelope biogenesis. The mycoloyl transferase activity of these proteins generates trehalose dimycolate (TDM), an envelope lipid essential for M. tuberculosis virulence, and cell wall arabinogalactan-linked mycolic acids. Inhibition of these enzymes through substrate analogs hinders growth of mycobacteria, but a link to mycolic acid synthesis has not been established. In this study, we characterized a novel inhibitor of Ag85C, 2-amino-6-propyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile (I3-AG85). I3-AG85 was isolated from a panel of four inhibitors that exhibited structure- and dose-dependent inhibition of M. tuberculosis division in broth culture. I3-AG85 also inhibited M. tuberculosis survival in infected primary macrophages. Importantly, it displayed an identical MIC against the drug-susceptible H37Rv reference strain and a panel of extensively drug-resistant/multidrug-resistant M. tuberculosis strains. Nuclear magnetic resonance analysis indicated binding of I3-AG85 to Ag85C, similar to its binding to the artificial substrate octylthioglucoside. Quantification of mycolic acid-linked lipids of the M. tuberculosis envelope showed a specific blockade of TDM synthesis. This was accompanied by accumulation of trehalose monomycolate, while the overall mycolic acid abundance remained unchanged. Inhibition of Ag85C activity also disrupted the integrity of the M. tuberculosis envelope. I3-AG85 inhibited the division of and reduced TDM synthesis in an M. tuberculosis strain deficient in Ag85C. Our results indicate that Ag85 proteins are promising targets for novel antimycobacterial drug design. PMID:22290959

Warrier, Thulasi; Tropis, Marielle; Werngren, Jim; Diehl, Anne; Gengenbacher, Martin; Schlegel, Brigitte; Schade, Markus; Oschkinat, Hartmut; Daffe, Mamadou; Hoffner, Sven; Eddine, Ali Nasser

2012-01-01

188

?-Pinene Inhibits Growth and Induces Oxidative Stress in Roots  

PubMed Central

• Background and Aims Determining the mode of action of allelochemicals is one of the challenging aspects in allelopathic studies. Recently, allelochemicals have been proposed to cause oxidative stress in target tissue and induce an antioxidant mechanism. ?-Pinene, one of the common monoterpenoids emitted from several aromatic plants including forest trees, is known for its growth-inhibitory activity. However, its mechanism of action remains unexplored. The aim of the present study was to determine the inhibitory effect of ?-pinene on root growth and generation of reactive oxygen species, as indicators of oxidative stress and changes in activities of antioxidant enzymes. • Methods Effects of ?-pinene on early root growth were studied in five test species, Cassia occidentalis, Amaranthus viridis, Triticum aestivum, Pisum sativum and Cicer arietinum. Electrolyte leakage, lipid peroxidation, hydrogen peroxide generation, proline accumulation, and activities of the enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT) and glutathione reductase (GR) were studied in roots of C. occidentalis. • Key Results ?-Pinene inhibited the radicle growth of all the test species. Exposure of C. occidentalis roots to ?-pinene enhanced solute leakage, and increased levels of malondialdehyde, proline and hydrogen peroxide, indicating lipid peroxidation and induction of oxidative stress. Activities of the antioxidant enzymes SOD, CAT, GPX, APX and GR were significantly elevated, thereby indicating the enhanced generation of reactive oxygen species (ROS) upon ?-pinene exposure. Increased levels of scavenging enzymes indicates their induction as a secondary defence mechanism in response to ?-pinene. • Conclusions It is concluded that ?-pinene inhibits early root growth and causes oxidative damage in root tissue through enhanced generation of ROS, as indicated by increased lipid peroxidation, disruption of membrane integrity and elevated antioxidant enzyme levels. PMID:17028297

SINGH, HARMINDER P.; BATISH, DAIZY R.; KAUR, SHALINDER; ARORA, KOMAL; KOHLI, RAVINDER K.

2006-01-01

189

Ricinoleic acid inhibits methanogenesis and fatty acid biohydrogenation in ruminal digesta from sheep and in bacterial cultures.  

PubMed

Ricinoleic acid (RA; 12-hydroxy-cis-9-18:1) is the main fatty acid component of castor oil. Although a precursor for CLA synthesis in lactic acid bacteria, RA was found previously not to form CLA in ruminal digesta but to have some inhibitory properties. The present study was undertaken to evaluate the potential of RA to modulate ruminal biohydrogenation and methanogenesis. Ruminal digesta from 4 sheep receiving a mixed hay-concentrate diet was incubated in vitro with 0.167 g/L of linoleic acid (LA; cis-9,cis-12-18:2) or with a combination of LA and RA or LA and castor oil (LA, RA, and castor oil added to a final concentration of 0.167 g/L) in the presence and absence of lipase. The CLA rumenic acid (cis-9,trans-11-18:2) accumulated when either RA or castor oil and lipase was present. Vaccenic acid (VA; trans-11-18:1) also accumulated, and a decrease of the rate of production of stearic acid (SA; 18:0) was observed. When LA was incubated with castor oil in the absence of lipase, no effects on biohydrogenation were observed. Ricinoleic acid at 0.02 g/L did not affect growth of Butyrivibrio fibrisolvens but it inhibited growth of Butyrivibrio proteoclasticus. Butyrivibrio proteoclasticus but not B. fibrisolvens metabolized RA to 12-hydroxystearate. Linoleic acid metabolism by B. proteoclasticus appeared to be unaffected by RA addition whereas rumenic acid accumulation increased (P = 0.015 at 12 h) when RA was added. A 28% decrease (P = 0.004) in methane was obtained in 24 h in vitro incubations of diluted buffered ruminal fluid with added 0.2 g RA/L. There was no effect on the total concentration of VFA after 24 h as a result of RA addition, but the molar proportions of acetate and butyrate were decreased (P = 0.041 and P < 0.001, respectively) whereas that of propionate increased (P < 0.001). It was concluded that, at least in vitro, RA or the combination of castor oil and lipase inhibit biohydrogenation, causing the accumulation of rumenic acid and VA, with potential health benefits for ruminant products. The effect appeared to be mediated via an inhibitory effect on the biohydrogenating activity of B. proteoclasticus. An added environmental benefit could be a concomitant decrease in methane emissions. In vivo studies are now required to confirm the potential of these additives. PMID:22829608

Ramos Morales, E; Mata Espinosa, M A; McKain, N; Wallace, R J

2012-12-01

190

Growth hormone-releasing hormone antagonists inhibit growth of human ovarian cancer  

Microsoft Academic Search

Epithelial ovarian carcinoma is the leading cause of cancer-related deaths among women with gynecologic malignancies. Antagonists of the growth hormone-releasing hormone (GHRH) have been shown to inhibit growth of various cancers through endocrine, autocrine, and paracrine mechanisms. In this study, we have investigated the effects of GHRH antagonists (GHRHa) in ES-2 human clear cell ovarian cancer and in UCI-107 human

A. Papadia; A. V. Schally; G. Halmos; J. L. Varga; S. Seitz; S. Buchholz; F. Rick; M. Zarandi; S. Bellyei; A. Treszl; L. Szalontay; J. A. Lucci

2011-01-01

191

Inhibition of myeloperoxidase-mediated hypochlorous acid production by nitroxides  

PubMed Central

Tissue damage resulting from the extracellular production of HOCl (hypochlorous acid) by the MPO (myeloperoxidase)-hydrogen peroxide-chloride system of activated phagocytes is implicated as a key event in the progression of a number of human inflammatory diseases. Consequently, there is considerable interest in the development of therapeutically useful MPO inhibitors. Nitroxides are well established antioxidant compounds of low toxicity that can attenuate oxidative damage in animal models of inflammatory disease. They are believed to exert protective effects principally by acting as superoxide dismutase mimetics or radical scavengers. However, we show here that nitroxides can also potently inhibit MPO-mediated HOCl production, with the nitroxide 4-aminoTEMPO inhibiting HOCl production by MPO and by neutrophils with IC50 values of approx. 1 and 6 ?M respectively. Structure–activity relationships were determined for a range of aliphatic and aromatic nitroxides, and inhibition of oxidative damage to two biologically-important protein targets (albumin and perlecan) are demonstrated. Inhibition was shown to involve one-electron oxidation of the nitroxides by the compound I form of MPO and accumulation of compound II. Haem destruction was also observed with some nitroxides. Inhibition of neutrophil HOCl production by nitroxides was antagonized by neutrophil-derived superoxide, with this attributed to superoxide-mediated reduction of compound II. This effect was marginal with 4-aminoTEMPO, probably due to the efficient superoxide dismutase-mimetic activity of this nitroxide. Overall, these data indicate that nitroxides have considerable promise as therapeutic agents for the inhibition of MPO-mediated damage in inflammatory diseases. PMID:19379130

Rees, Martin D.; Bottle, Steven E.; Fairfull-Smith, Kathryn E.; Malle, Ernst; Whitelock, John M.; Davies, Michael J.

2014-01-01

192

Inhibition by sporidesmin of hepatocyte bile acid transport.  

PubMed

Exposure of isolated rat hepatocytes (approx. 2 x 10(7)--5 x 10(7) cells/10ml of incubation mixture) to 0.5 mg of the mycotoxin sporidesmin for 30--60 min at 37 degrees C produced loss of plasma-membrane microvilli with some disruption of organelle distribution in the sub-surface region. There was accompanying inhibition of [14C]cholate and [14C]taurocholate transport, but bile acid conjugation was not altered. Inhibition of cholate uptake was maximal after exposure of hepatocytes to sporidesmin for 1 min, and was not reversed by washing cells free of extracellular sporidesmin. N-Ethylmaleimide (0.1 mM) or dithiothreitol (1 mM) partially protected hepatocytes from sporidesmin inhibition of bile acid uptake. Significant protection was not given by other thiols or by zinc sulphate, cholesterol, ascorbate or alpha-tocopherol. The results are discussed in terms of sporidesmin action on cell membranes and the toxin's effect on bile secretion. PMID:6870851

Cordiner, S J; Jordan, T W

1983-04-15

193

Inhibition by sporidesmin of hepatocyte bile acid transport.  

PubMed Central

Exposure of isolated rat hepatocytes (approx. 2 x 10(7)--5 x 10(7) cells/10ml of incubation mixture) to 0.5 mg of the mycotoxin sporidesmin for 30--60 min at 37 degrees C produced loss of plasma-membrane microvilli with some disruption of organelle distribution in the sub-surface region. There was accompanying inhibition of [14C]cholate and [14C]taurocholate transport, but bile acid conjugation was not altered. Inhibition of cholate uptake was maximal after exposure of hepatocytes to sporidesmin for 1 min, and was not reversed by washing cells free of extracellular sporidesmin. N-Ethylmaleimide (0.1 mM) or dithiothreitol (1 mM) partially protected hepatocytes from sporidesmin inhibition of bile acid uptake. Significant protection was not given by other thiols or by zinc sulphate, cholesterol, ascorbate or alpha-tocopherol. The results are discussed in terms of sporidesmin action on cell membranes and the toxin's effect on bile secretion. Images PLATE 1 PLATE 2 PMID:6870851

Cordiner, S J; Jordan, T W

1983-01-01

194

Catechin-incorporated dental copolymers inhibit growth of Streptococcus mutans  

PubMed Central

Objective: To test the inhibitory growth activity of green tea catechin incorporated into dental resins compared to resins containing the broad-spectrum antimicrobial compound chlorhexidine against Streptococcus mutans in vitro. Material and Methods: The minimum inhibitory concentrations (MICs) of epigallocatechin-gallate (EGCg) and chlorhexidine (CHX) were determined according to the microdilution method. Resin discs (5 mm x 3 mm) were prepared from Bis-GMA/TEGDMA (R1) and Bis-GMA/CH3Bis-GMA (R2) comonomers (n=9) containing: a) no drug, b) EGCg, c) CHX. Two concentrations of each drug (0.5x MIC and 1x MIC) were incorporated into the resin discs. Samples were individually immersed in a bacterial culture and incubated for 24 h at 37º C under constant agitation. Cell viability was assessed by counting the number of colonies on replica agar plates. Statistical analysis was performed using one-way ANOVA, Tukey and Student t-tests (?=0.05). Results: Both resins containing EGCg and CHX showed a significant inhibition of bacterial growth at both concentrations tested (p<0.05). A significantly higher inhibition was observed in response to resins containing CHX at 0.5x MIC and 1x MIC, and EGCg at 1x MIC when compared to EGCg at 0.5x MIC. Also, EGCg at 0.5x MIC in R1 had a significantly higher growth inhibition than in R2. Conclusions: Both EGCg and CHX retained their antibacterial activity when incorporated into the resin matrix. EGCg at 1x MIC in R1 and R2 resins significantly reduced S. mutans survival at a level similar to CHX. The data generated from this study will provide advances in the field of bioactive dental materials with the potential of improving the lifespan of resin-based restorations. PMID:23739855

MANKOVSKAIA, Alexandra; LEVESQUE, Celine M.; PRAKKI, Anuradha

2013-01-01

195

Inhibition of C4 photosynthesis by (benzamidooxy)acetic acid.  

PubMed

(Benzamidooxy)acetic acid (common name benzadox) which has herbicidal properties was evaluated as a potential inhibitor of photosynthesis in C4 plants. Among enzymes of the C4 pathway, it was a relatively strong inhibitor of alanine aminotransferase in in vitro experiments at concentrations of 5mM. In benzadox treated leaves of Panicum miliaceum, a NAD-malic enzyme type C4 species, there was strong inhibition of both alanine and aspartate aminotransferase and of photosynthetic O2 evolution within one hour. Consistent with the inhibition of these enzymes of the C4 cycle, the pool sizes of metabolites of the cycle was altered: the aspartate level was increased two fold, while the levels of other metabolites such as pyruvate, alanine, oxalacetate and malate were decreased. Kinetic studies with partially purified alanine aminotransferase showed that benzadox is a competitive inhibitor with respect to alanine and a noncompetitive inhibitor with respect to 2-oxoglutarate. Comparisons between the structures and inhibitory actions of benzadox and (aminooxy)acetic acid, the latter a potent inhibitor of alanine and aspartate aminotransferases, suggest that in vivo, benzadox may exert its effect through metabolism to (aminooxy)acetic acid. PMID:24458342

Nakamoto, H; Ku, M S; Edwards, G E

1982-12-01

196

Inhibition of Flowering in Hyoscyamus niger by 6Azauracil without Suppression of Stem Growth  

Microsoft Academic Search

IN Hyoscyamus niger the uracil analogue 6-azauracil has partially inhibited photoperiodic induction and caused malformations of young leaves, but these phenomena were not associated with an inhibition of stem growth. Application of pyrimidine analogues usually causes an inhibition of growth processes which involve cell division2-4 as well as cell elongation5,6. Inhibition can cause abnormal growth of the cells, thus leading

F. Seidlová; J. Krekule; L. Teltscherová

1967-01-01

197

Inhibition of melanoma tumor growth in vivo by survivin targeting  

PubMed Central

A role of apoptosis (programmed cell death) in tumor formation and growth was investigated by targeting the apoptosis inhibitor survivin in vivo. Expression of a phosphorylation-defective survivin mutant (Thr34?Ala) triggered apoptosis in several human melanoma cell lines and enhanced cell death induced by the chemotherapeutic drug cisplatin in vitro. Conditional expression of survivin Thr34?Ala in YUSAC2 melanoma cells prevented tumor formation upon s.c. injection into CB.17 severe combined immunodeficient-beige mice. When induced in established melanoma tumors, survivin Thr34?Ala inhibited tumor growth by 60–70% and caused increased apoptosis and reduced proliferation of melanoma cells in vivo. Manipulation of the antiapoptotic pathway maintained by survivin may be beneficial for cancer therapy. PMID:11149963

Grossman, Douglas; Kim, Paul J.; Schechner, Jeffrey S.; Altieri, Dario C.

2001-01-01

198

Inhibition of calcium oxalate monohydrate crystal growth using polyelectrolytes  

NASA Astrophysics Data System (ADS)

The effects of polyacrylic acid and poly(ethylene glycol-block-acrylic acid) copolymer on the growth of calcium oxalate monohydrate (COM), a common renal stone constituent, have been investigated in aqueous solutions at 37 °C. A constant composition method has been utilized to investigate the crystallization kinetics of COM. The results of the experiment show that the retardation in mass transport in growth process is controlled by the nature of the polymer and its concentration. Monoclinic COM crystals were shown to be major components in the absence of polymers. In the presence of polymers monoclinic COM crystals were smaller and some of the crystals were less elongated, and small number of crystals grew in the shape of three-dimensional hexagonal prisms. The data on the growth kinetics of crystals in the presence of polyelectrolytes were examined from the standpoint of adsorption models. Polyelectrolyte effects were interpreted in terms of the adsorption of inhibitors onto the active growth sites on the crystal surface.

Akyol, Emel; Öner, Mualla

2007-09-01

199

Xanthine oxidase inhibits growth of Plasmodium falciparum in human erythrocytes in vitro.  

PubMed Central

Malaria parasites, unable to synthesize purine de novo, use host-derived hypoxanthine preferentially as purine source. In a previous study (1990. J. Biol. Chem. 265:6562-6568), we noted that xanthine oxidase rapidly and completely depleted hypoxanthine in human erythrocytes, not by crossing the erythrocyte membrane, but rather by creating a concentration gradient which facilitated hypoxanthine efflux. We therefore investigated the ability of xanthine oxidase to inhibit growth of FCR-3, a chloroquine-resistant strain of Plasmodium falciparum in human erythrocytes in vitro. Parasites were cultured in human group O+ erythrocytes in medium supplemented, as required, with xanthine oxidase or chloroquine. Parasite viability was assessed by uptake of radiolabeled glycine and adenosine triphosphate-derived purine into protein and nucleic acid, respectively, by nucleic acid accumulation, by L-lactate production, and by microscopic appearance. On average, a 90% inhibition of growth was observed after 72 h of incubation in 20 mU/ml xanthine oxidase. Inhibition was notably greater than that exerted by 10(-7) M chloroquine (less than 10%) over a comparable period. The IC50 for xanthine oxidase was estimated at 0.2 mU/ml, compared to 1.5 x 10(-7) M for chloroquine. Inhibition was completely reversed by excess hypoxanthine, but was unaffected by oxygen radical scavengers, including superoxide dismutase and catalase. The data confirms that a supply of host-derived hypoxanthine is critical for nucleic acid synthesis in P. falciparum, and that depletion of erythrocyte hypoxanthine pools of chloroquine-resistant malaria infection in humans. of chloroquine-resistant malaria infection in humans. Images PMID:1752946

Berman, P A; Human, L; Freese, J A

1991-01-01

200

Mo polyoxometalate nanoparticles inhibit tumor growth and vascular endothelial growth factor induced angiogenesis  

NASA Astrophysics Data System (ADS)

Tumor growth depends on angiogenesis, which can furnish the oxygen and nutrients that proliferate tumor cells. Thus, blocking angiogenesis can be an effective strategy to inhibit tumor growth. In this work, three typical nanoparticles based on polyoxometalates (POMs) have been prepared; we investigated their capability as antitumor and anti-angiogenesis agents. We found that Mo POM nanoparticles, especially complex 3, inhibited the growth of human hepatocellular liver carcinoma cells (HepG2) through cellular reactive oxygen species levels’ elevation and mitochondrial membrane potential damage. Complex 3 also suppressed the proliferation, migration, and tube formation of endothelial cells in vitro and chicken chorioallantoic membrane development ex vivo. Furthermore, western blot analysis of cell signaling molecules indicated that Mo POMs blocked the vascular endothelial growth factor receptor 2-mediated ERK1/2 and AKT signaling pathways in endothelial cells. Using transmission electron microscopy, we demonstrated their cellular uptake and localization within the cytoplasm of HepG2 cells. These results indicate that, owing to the extraordinary physical and chemical properties, Mo POM nanoparticles can significantly inhibit tumor growth and angiogenesis, which makes them potential drug candidates in anticancer and anti-angiogenesis therapies.

Zheng, Wenjing; Yang, Licong; Liu, Ying; Qin, Xiuying; Zhou, Yanhui; Zhou, Yunshan; Liu, Jie

2014-06-01

201

RPA Inhibition increases Replication Stress and Suppresses Tumor Growth  

PubMed Central

The ATR/Chk1 pathway is a critical surveillance network that maintains genomic integrity during DNA replication by stabilizing the replication forks during normal replication to avoid replication stress. One of the many differences between normal cells and cancer cells is the amount of replication stress that occurs during replication. Cancer cells with activated oncogenes generate increased levels of replication stress. This creates an increased dependency on the ATR/Chk1 pathway in cancer cells and opens up an opportunity to preferentially kill cancer cells by inhibiting this pathway. In support of this idea, we have identified a small molecule termed HAMNO ((1Z)-1-[(2-hydroxyanilino)methylidene]naphthalen-2-one), a novel protein interaction inhibitor of replication protein A (RPA), a protein involved in the ATR/Chk1 pathway. HAMNO selectively binds the N-terminal domain of RPA70, effectively inhibiting critical RPA protein interactions which rely on this domain. HAMNO inhibits both ATR autophosphorylation and phosphorylation of RPA32 Ser33 by ATR. By itself, HAMNO treatment creates DNA replication stress in cancer cells that are already experiencing replication stress, but not in normal cells, and it acts synergistically with etoposide to kill cancer cells in vitro and slow tumor growth in vivo. Thus, HAMNO illustrates how RPA inhibitors represent candidate therapeutics for cancer treatment, providing disease selectivity in cancer cells by targeting their differential response to replication stress. PMID:25070753

Glanzer, Jason G.; Liu, Shengqin; Wang, Ling; Mosel, Adam; Peng, Aimin; Oakley, Greg G.

2014-01-01

202

Praziquantel synergistically enhances paclitaxel efficacy to inhibit cancer cell growth.  

PubMed

The major challenges we are facing in cancer therapy with paclitaxel (PTX) are the drug resistance and severe side effects. Massive efforts have been made to overcome these clinical challenges by combining PTX with other drugs. In this study, we reported the first preclinical data that praziquantel (PZQ), an anti-parasite agent, could greatly enhance the anticancer efficacy of PTX in various cancer cell lines, including PTX-resistant cell lines. Based on the combination index value, we demonstrated that PZQ synergistically enhanced PTX-induced cell growth inhibition. The co-treatment of PZQ and PTX also induced significant mitotic arrest and activated the apoptotic cascade. Moreover, PZQ combined with PTX resulted in a more pronounced inhibition of tumor growth compared with either drug alone in a mouse xenograft model. We tried to investigate the possible mechanisms of this synergistic efficacy induced by PZQ and PTX, and we found that the co-treatment of the two drugs could markedly decrease expression of X-linked inhibitor of apoptosis protein (XIAP), an anti-apoptotic protein. Our data further demonstrated that down-regulation of XIAP was required for the synergistic interaction between PZQ and PTX. Together, this study suggested that the combination of PZQ and PTX may represent a novel and effective anticancer strategy for optimizing PTX therapy. PMID:23251610

Wu, Zhen Hua; Lu, Ming-ke; Hu, Long Yu; Li, Xiaotong

2012-01-01

203

Identification of volatile compounds produced by the bacterium Burkholderia tropica that inhibit the growth of fungal pathogens  

PubMed Central

It has been documented that bacteria from the Burkholderia genera produce different kinds of compounds that inhibit plant pathogens, however in Burkholderia tropica, an endophytic diazotrophic and phosphate-solubilizing bacterium isolated from a wide diversity of plants, the capacity to produce antifungal compounds has not been evaluated. In order to expand our knowledge about Burkholderia tropica as a potential biological control agent, we analyzed 15 different strains of this bacterium to evaluate their capacities to inhibit the growth of four phytopathogenic fungi, Colletotrichum gloeosporioides, Fusarium culmorum, Fusarium oxysporum and Sclerotium rolffsi. Diverse analytical techniques, including plant root protection and dish plate growth assays and gas chromatography-mass spectroscopy showed that the fungal growth inhibition was intimately associated with the volatile compounds produced by B. tropica and, in particular, two bacterial strains (MTo293 and TTe203) exhibited the highest radial mycelial growth inhibition. Morphological changes associated with these compounds, such as disruption of fungal hyphae, were identified by using photomicrographic analysis. By using gas chromatography-mass spectroscopy technique, 18 volatile compounds involved in the growth inhibition mechanism were identified, including ?-pinene and limonene. In addition, we found a high proportion of bacterial strains that produced siderophores during growth with different carbon sources, such as alanine and glutamic acid; however, their roles in the antagonism mechanism remain unclear. PMID:23680857

Tenorio-Salgado, Silvia; Tinoco, Raunel; Vazquez-Duhalt, Rafael; Caballero-Mellado, Jesus; Perez-Rueda, Ernesto

2013-01-01

204

15-Lipoxygenase Metabolites of Docosahexaenoic Acid Inhibit Prostate Cancer Cell Proliferation and Survival  

PubMed Central

A 15-LOX, it is proposed, suppresses the growth of prostate cancer in part by converting arachidonic, eicosatrienoic, and/or eicosapentaenoic acids to n-6 hydroxy metabolites. These metabolites inhibit the proliferation of PC3, LNCaP, and DU145 prostate cancer cells but only at ?1–10 µM. We show here that the 15-LOX metabolites of docosahexaenoic acid (DHA), 17-hydroperoxy-, 17-hydroxy-, 10,17-dihydroxy-, and 7,17-dihydroxy-DHA inhibit the proliferation of these cells at ?0.001, 0.01, 1, and 1 µM, respectively. By comparison, the corresponding 15-hydroperoxy, 15-hydroxy, 8,15-dihydroxy, and 5,15-dihydroxy metabolites of arachidonic acid as well as DHA itself require ?10–100 µM to do this. Like DHA, the DHA metabolites a) induce PC3 cells to activate a peroxisome proliferator-activated receptor-? (PPAR?) reporter, express syndecan-1, and become apoptotic and b) are blocked from slowing cell proliferation by pharmacological inhibition or knockdown of PPAR? or syndecan-1. The DHA metabolites thus slow prostate cancer cell proliferation by engaging the PPAR?/syndecan-1 pathway of apoptosis and thereby may contribute to the prostate cancer-suppressing effects of not only 15-LOX but also dietary DHA. PMID:23029040

O'Flaherty, Joseph T.; Hu, Yungping; Wooten, Rhonda E.; Horita, David A.; Samuel, Michael P.; Thomas, Michael J.; Sun, Haiguo; Edwards, Iris J.

2012-01-01

205

Proteolytic Pathways Induced by Herbicides That Inhibit Amino Acid Biosynthesis  

PubMed Central

Background The herbicides glyphosate (Gly) and imazamox (Imx) inhibit the biosynthesis of aromatic and branched-chain amino acids, respectively. Although these herbicides inhibit different pathways, they have been reported to show several common physiological effects in their modes of action, such as increasing free amino acid contents and decreasing soluble protein contents. To investigate proteolytic activities upon treatment with Gly and Imx, pea plants grown in hydroponic culture were treated with Imx or Gly, and the proteolytic profile of the roots was evaluated through fluorogenic kinetic assays and activity-based protein profiling. Results Several common changes in proteolytic activity were detected following Gly and Imx treatment. Both herbicides induced the ubiquitin-26 S proteasome system and papain-like cysteine proteases. In contrast, the activities of vacuolar processing enzymes, cysteine proteases and metacaspase 9 were reduced following treatment with both herbicides. Moreover, the activities of several putative serine protease were similarly increased or decreased following treatment with both herbicides. In contrast, an increase in YVADase activity was observed under Imx treatment versus a decrease under Gly treatment. Conclusion These results suggest that several proteolytic pathways are responsible for protein degradation upon herbicide treatment, although the specific role of each proteolytic activity remains to be determined. PMID:24040092

Zulet, Amaia; Gil-Monreal, Miriam; Villamor, Joji Grace; Zabalza, Ana; van der Hoorn, Renier A. L.; Royuela, Mercedes

2013-01-01

206

Effects of ferulic acid and some of its microbial metabolic products on radicle growth of cucumber  

Microsoft Academic Search

An initial survey of the effects of aqueous solutions of ferulic acid and three of its microbial metabolic products at pH 4.5, 6.0, and 7.5 was determined on radicle growth of 11 crop species in Petri dishes. These bioassays indicated that cucumber, ladino clover, lettuce, mung bean, and wheat were inhibited by ferulic, caffeic, protocatechuic, and\\/or vanillic acids and that

Udo Blum; Barry R. Dalton; John O. Rawlings

1984-01-01

207

Use of virginiamycin to control the growth of lactic acid bacteria during alcohol fermentation  

Microsoft Academic Search

  The antibiotic virginiamycin was investigated for its effects on growth and lactic acid production by seven strains of lactobacilli\\u000a during the alcoholic fermentation of wheat mash by yeast. The lowest concentration of virginiamycin tested (0.5?mg Lactrol\\u000a TMkg?1 mash), was effective against most of the lactic acid bacteria under study, but Lactobacillus plantarum was not significantly inhibited at this concentration. The

S H Hynes; D M Kjarsgaard; K C Thomas; W M Ingledew

1997-01-01

208

Boric acid inhibits germination and colonization of Saprolegnia spores in vitro and in vivo.  

PubMed

Saprolegnia infections cause severe economic losses among freshwater fish and their eggs. The banning of malachite green increased the demand for finding effective alternative treatments to control the disease. In the present study, we investigated the ability of boric acid to control saprolegniosis in salmon eggs and yolk sac fry. Under in vitro conditions, boric acid was able to decrease Saprolegnia spore activity and mycelial growth in all tested concentrations above 0.2 g/L, while complete inhibition of germination and growth was observed at a concentration of 0.8 g/L. In in vivo experiments using Atlantic salmon eyed eggs, saprolegniosis was controlled by boric acid at concentrations ranging from 0.2-1.4 g/L during continuous exposure, and at 1.0-4.0 g/L during intermittent exposure. The same effect was observed on salmon yolk sac fry exposed continuously to 0.5 g/L boric acid during the natural outbreak of saprolegniosis. During the experiments no negative impact with regard to hatchability and viability was observed in either eggs or fry, which indicate safety of use at all tested concentrations. The high hatchability and survival rates recorded following the in vivo testing suggest that boric acid is a candidate for prophylaxis and control of saprolegniosis. PMID:24699283

Ali, Shimaa E; Thoen, Even; Evensen, Øystein; Skaar, Ida

2014-01-01

209

Kinetic-spectrophotometric determination of ascorbic acid by inhibition of the hydrochloric acid-bromate reaction  

NASA Astrophysics Data System (ADS)

A new analytical method was developed for the determination of ascorbic acid in fruit juice and pharmaceuticals. The method is based on its inhibition effect on the reaction between hydrochloric acid and bromate. The decolourisation of Methyl Orange by the reaction products was used to monitor the reaction spectrophotometrically at 510 nm. The linearity range of the calibration graph depends on bromate concentration. The variable affecting the rate of the reaction was investigated. The method is simple, rapid, relatively sensitive and precise. The limit of detection is 7.6×10 -6 M and calibration rang is 8×10 -6-1.2×10 -3 M ascorbic acid. The relative standard deviation of seven replication determinations of 8×10 -6 and 2×10 -5 M ascorbic acid was 2.8 and 1.7%, respectively. The influence of potential interfering substance was studied. The method was successfully applied for the determination of ascorbic acid in pharmaceuticals.

Ensafi, Ali A.; Rezaei, B.; Movahedinia, H.

2002-10-01

210

Dynamic Light Scattering Study of Inhibition of Nucleation and Growth of Hydroxyapatite Crystals by Osteopontin  

PubMed Central

We study the effect of isoforms of osteopontin (OPN) on the nucleation and growth of crystals from a supersaturated solution of calcium and phosphate ions. Dynamic light scattering is used to monitor the size of the precipitating particles and to provide information about their concentration. At the ion concentrations studied, immediate precipitation was observed in control experiments with no osteopontin in the solution, and the size of the precipitating particles increased steadily with time. The precipitate was identified as hydroxyapatite by X-ray diffraction. Addition of native osteopontin (nOPN) extracted from rat bone caused a delay in the onset of precipitation and reduced the number of particles that formed, but the few particles that did form grew to a larger size than in the absence of the protein. Recombinant osteopontin (rOPN), which lacks phosphorylation, caused no delay in initial calcium phosphate precipitation but severely slowed crystal growth, suggesting that rOPN inhibits growth but not nucleation. rOPN treated with protein kinase CK2 to phosphorylate the molecule (p-rOPN) produced an effect similar to that of nOPN, but at higher protein concentrations and to a lesser extent. These results suggest that phosphorylations are critical to OPN’s ability to inhibit nucleation, whereas the growth of the hydroxyapatite crystals is effectively controlled by the highly acidic OPN polypeptide. This work also demonstrates that dynamic light scattering can be a powerful tool for delineating the mechanism of protein modulation of mineral formation. PMID:23457612

de Bruyn, John R.; Goiko, Maria; Mozaffari, Maryam; Bator, Daniel; Dauphinee, Ron L.; Liao, Yinyin; Flemming, Roberta L.; Bramble, Michael S.; Hunter, Graeme K.; Goldberg, Harvey A.

2013-01-01

211

Bile acids inhibit NAD+-dependent 15-hydroxyprostaglandin dehydrogenase transcription in colonocytes.  

PubMed

Multiple lines of evidence have suggested a role for both bile acids and prostaglandins (PG) in gastrointestinal carcinogenesis. Levels of PGE(2) are determined by both synthesis and catabolism. Previously, bile acid-mediated induction of cyclooxygenase-2 (COX-2) was found to stimulate PGE(2) synthesis. NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the key enzyme responsible for the catabolism of PGE(2), has been linked to colorectal carcinogenesis. In this study, we determined whether bile acids altered the expression of 15-PGDH in human colon cancer cell lines. Treatment with unconjugated bile acids (chenodeoxycholate and deoxycholate) suppressed the transcription of 15-PGDH, resulting in reduced amounts of 15-PGDH mRNA, protein, and enzyme activity. Conjugated bile acids were less potent suppressors of 15-PGDH expression than unconjugated bile acids. Treatment with chenodeoxycholate activated protein kinase C (PKC), leading in turn to increased extracellular signal-regulated kinase (ERK) 1/2 activity. Small molecules that inhibited bile acid-mediated activation of PKC and ERK1/2 also blocked the downregulation of 15-PGDH. Bile acids induced early growth response factor-1 (Egr-1) and Snail, a repressive transcription factor that bound to the 15-PGDH promoter. Silencing Egr-1 or Snail blocked chenodeoxycholate-mediated downregulation of 15-PGDH. Together, these data indicate that bile acids activate the signal transduction pathway PKC --> ERK1/2 --> Egr-1 --> Snail and thereby suppress 15-PGDH transcription. Bile acids appear to increase the release of PGs from cells by downregulating catabolism in addition to stimulating synthesis. These results provide new mechanistic insights into the link between bile acids and gastrointestinal carcinogenesis. PMID:19608733

Miyaki, Akira; Yang, Peiying; Tai, Hsin-Hsiung; Subbaramaiah, Kotha; Dannenberg, Andrew J

2009-09-01

212

Opioid growth factor - opioid growth factor receptor axis inhibits proliferation of triple negative breast cancer.  

PubMed

Triple negative breast cancer (TNBC) represents approximately 15% of the newly diagnosed cancers worldwide and is characterized by tissue lacking in estrogen, progesterone and human epidermal growth factor receptors. TNBC disproportionately affects younger women and women of colour, and new treatments are needed. The opioid growth factor (OGF) - opioid growth factor receptor (OGFr) axis is a determinant of cell proliferation in neoplasia, and OGF is an endogenously produced pentapeptide that inhibits cell replication by interacting with OGFr and upregulating cyclin-dependent inhibitory kinase pathways thus reducing DNA synthesis. In these studies we investigated the presence and function of the OGF-OGFr axis in two human TNBC cell lines, as well as in breast cancer cell lines containing hormonal receptors. TNBC cell lines MDA-MD-231 and BT-20, as well as human breast cancer cells SK-BR-3 and MCF-7, were examined for the presence of pentapeptide and receptors, as well as their response to OGF. Specificity of peptide and receptor was confirmed by antibody neutralization and molecular studies to knockdown classical receptor protein. The requirement for protein transcription and translation and RNA transcription were investigated. Growth of TNBC cells in the presence of OGF and standard of care chemotherapeutic agent paclitaxel was evaluated to determine both efficacy and protective effects against toxicity. OGF treatment inhibited TNBC cells in a dosage related, receptor mediated, and reversible manner. OGF was the specific endogenous opioid to inhibit cell proliferation, and this was mediated by p21 cyclin dependent inhibitory kinase pathways, and required protein and RNA synthesis. OGFr was the specific receptor involved; both peptide and receptor were detected in all four cell lines. OGF treatment inhibited growth of all cancer cell lines evaluated, and reduced cell death in cultures exposed to paclitaxel. The OGF-OGFr axis is present and functioning in TNBC cell lines, and provides a novel biological pathway as potential therapy. PMID:23918871

Zagon, Ian S; Porterfield, Nancy K; McLaughlin, Patricia J

2013-06-01

213

Bioactive compound from Pseudomonas synxantha inhibits the growth of Mycobacteria.  

PubMed

Tuberculosis is a dreaded disease and the current situation demands new anti-tubercular agent(s) for the management of public health. Towards this direction, we obtained a contaminant organism on a Mycobacterium smegmatis lawn having growth inhibitory activity against the later. In the current study, efforts were targeted to identify this organism and characterize the bioactive compound from this isolate that inhibited the growth of Mycobacteria. The result revealed that the organism is a strain of Pseudomonas synxantha. Biophysical analyses including (1)H and (13)C NMR, ESI-mass spectroscopy, FTIR showed that the bioactive compound is a long chain aliphatic hydrocarbon with a terminal alyl bond and intermediate electronegative atom. The compound exhibited strong growth inhibitory activities against M. smegmatis and Mycobacterium tuberculosis strains H37Ra, H37Rv and BCG. Further experiments showed that both P. synxantha and its secretory metabolites are capable of inducing hemolysis of human blood. Thus the results of this study clearly indicate that the bioactive compound produced by P. Synxantha has biosurfactant activities as well as anti-myco-bacterial properties. PMID:24439826

Mukherjee, Koushik; Mandal, Santanu; Mukhopadhyay, Balaram; Mandal, Nitai Chandra; Sil, Alok Kumar

2014-01-01

214

Inhibition of the thioesterase activity of human fatty acid synthase by 1,4- and 9,10-diones.  

PubMed

Fatty acid synthase (FASN) is the enzyme that synthesizes fatty acids de novo in human cells. Although FASN is generally expressed at low levels in most normal tissues, its expression is highly upregulated in many cancers. Consistent with this notion, inhibition of FASN activity has demonstrated potential to halt proliferation and induce cell death in vitro and to block tumor growth in vivo. Consequently, FASN is widely recognized as a valuable therapeutic target. In this report, we describe a variety of 1,4-quinones and 9,10-anthraquinones, including several natural compounds and some newly synthesized compounds, that potently inhibit the thioesterase (TE) domain of FASN. Inhibition of recombinant TE activity, inhibition of cellular FASN, and cytotoxicity in human prostate cancer cell lines and normal fibroblasts, is shown for the most potent inhibitors. Collectively, the data illustrate the novel inhibitory capacity of the 1,4-quinone and 9,10-anthraquinone pharmacophores against FASN. PMID:25177021

Odens, Herman; Lowther, Todd; Kridel, Steven; Watts, Laura; Filipponi, Lauren; Schmitt, Jeffrey

2014-01-01

215

p8 inhibits the growth of human pancreatic cancer cells and its expression is induced through pathways involved in growth inhibition and repressed by factors promoting cell growth  

PubMed Central

Background p8 is a stress-induced protein with multiple functions and biochemically related to the architectural factor HMG-I/Y. We analyzed the expression and function of p8 in pancreatic cancer-derived cells. Methods Expression of p8 was silenced in the human pancreatic cancer cell lines Panc-1 and BxPc-3 by infection with a retrovirus expressing p8 RNA in the antisense orientation. Cell growth was measured in control and p8-silenced cells. Influence on p8 expression of the induction of intracellular pathways promoting cellular growth or growth arrest was monitored. Results p8-silenced cells grew more rapidly than control cells transfected with the empty retrovirus. Activation of the Ras?Raf?MEK?ERK and JNK intracellular pathways down-regulated p8 expression. In addition, the MEK1/2 inhibitor U0126 and the JNK inhibitor SP600125 up-regulates expression of p8. Conversely, p38 or TGF?-1 induced p8 expression whereas the specific p38 inhibitor SB203580 down-regulated p8 expression. Finally, TGF?-1 induction was in part mediated through p38. Conclusions p8 inhibits the growth of human pancreatic cancer cells. p8 expression is induced through pathways involved in growth inhibition and repressed by factors that promote cell growth. These results suggest that p8 belongs to a pathway regulating the growth of pancreatic cancer cells. PMID:14613582

Malicet, Cedric; Lesavre, Nathalie; Vasseur, Sophie; Iovanna, Juan L

2003-01-01

216

Inhibition of vascular endothelial growth factor-induced angiogenesis suppresses tumour growth in vivo  

Microsoft Academic Search

THE development of new blood vessels (angiogenesis) is required for many physiological processes including embryogenesis, wound healing and corpus luteum formation1,2. Blood vessel neoformation is also important in the pathogenesis of many disorders1-5, particularly rapid growth and metastasis of solid tumours3-5. There are several potential mediators of tumour angiogenesis, including basic and acidic fibroblast growth factors, tumour necrosis factor-alpha and

K. Jin Kim; Bing Li; Jane Winer; Mark Armanini; Nancy Gillett; Heidi S. Phillips; Napoleone Ferrara

1993-01-01

217

Boric acid inhibits embryonic histone deacetylases: A suggested mechanism to explain boric acid-related teratogenicity  

SciTech Connect

Histone deacetylases (HDAC) control gene expression by changing histonic as well as non histonic protein conformation. HDAC inhibitors (HDACi) are considered to be among the most promising drugs for epigenetic treatment for cancer. Recently a strict relationship between histone hyperacetylation in specific tissues of mouse embryos exposed to two HDACi (valproic acid and trichostatin A) and specific axial skeleton malformations has been demonstrated. The aim of this study is to verify if boric acid (BA), that induces in rodents malformations similar to those valproic acid and trichostatin A-related, acts through similar mechanisms: HDAC inhibition and histone hyperacetylation. Pregnant mice were treated intraperitoneally with a teratogenic dose of BA (1000 mg/kg, day 8 of gestation). Western blot analysis and immunostaining were performed with anti hyperacetylated histone 4 (H4) antibody on embryos explanted 1, 3 or 4 h after treatment and revealed H4 hyperacetylation at the level of somites. HDAC enzyme assay was performed on embryonic nuclear extracts. A significant HDAC inhibition activity (compatible with a mixed type partial inhibition mechanism) was evident with BA. Kinetic analyses indicate that BA modifies substrate affinity by a factor {alpha} = 0.51 and maximum velocity by a factor {beta} = 0.70. This work provides the first evidence for HDAC inhibition by BA and suggests such a molecular mechanism for the induction of BA-related malformations.

Di Renzo, Francesca [Department of Biology, University of Milan, Via Celoria, 26. 20133 Milan (Italy); Cappelletti, Graziella [Department of Biology, University of Milan, Via Celoria, 26. 20133 Milan (Italy); Broccia, Maria L. [Department of Biology, University of Milan, Via Celoria, 26. 20133 Milan (Italy); Giavini, Erminio [Department of Biology, University of Milan, Via Celoria, 26. 20133 Milan (Italy); Menegola, Elena [Department of Biology, University of Milan, Via Celoria, 26. 20133 Milan (Italy)]. E-mail: elena.menegola@unimi.it

2007-04-15

218

Fibroblast Growth Factor 21 (FGF21) Inhibits Chondrocyte Function and Growth Hormone Action Directly at the Growth Plate  

PubMed Central

Fibroblast growth factor 21 (FGF21) modulates glucose and lipid metabolism during fasting. In addition, previous evidence indicates that increased expression of FGF21 during chronic food restriction is associated with reduced bone growth and growth hormone (GH) insensitivity. In light of the inhibitory effects on growth plate chondrogenesis mediated by other FGFs, we hypothesized that FGF21 causes growth inhibition by acting directly at the long bones' growth plate. We first demonstrated the expression of FGF21, FGFR1 and FGFR3 (two receptors known to be activated by FGF21) and ?-klotho (a co-receptor required for the FGF21-mediated receptor binding and activation) in fetal and 3-week-old mouse growth plate chondrocytes. We then cultured mouse growth plate chondrocytes in the presence of graded concentrations of rhFGF21 (0.01–10 ?g/ml). Higher concentrations of FGF21 (5 and 10 ?g/ml) inhibited chondrocyte thymidine incorporation and collagen X mRNA expression. 10 ng/ml GH stimulated chondrocyte thymidine incorporation and collagen X mRNA expression, with both effects prevented by the addition in the culture medium of FGF21 in a concentration-dependent manner. In addition, FGF21 reduced GH binding in cultured chondrocytes. In cells transfected with FGFR1 siRNA or ERK 1 siRNA, the antagonistic effects of FGF21 on GH action were all prevented, supporting a specific effect of this growth factor in chondrocytes. Our findings suggest that increased expression of FGF21 during food restriction causes growth attenuation by antagonizing the GH stimulatory effects on chondrogenesis directly at the growth plate. In addition, high concentrations of FGF21 may directly suppress growth plate chondrocyte proliferation and differentiation. PMID:22696219

Wu, Shufang; Levenson, Amy; Kharitonenkov, Alexei; De Luca, Francesco

2012-01-01

219

Inhibition of Breast Cancer Cell Growth in Vitro by a Tyrosine Kinase Inhibitor1  

Microsoft Academic Search

Human breast cancer cell proliferation is regulated by growth factors that bind to receptors with intrinsic tyrosine kinase (TK) activity, includ ing the epidermal growth factor (EGF) receptor. To determine whether inhibition of receptor TK activity inhibits tumor growth, we studied the effects of a tyrosine kinase inhibitor, RG-13022, on cultured human breast cancer cells. RG-13022 represents a class of

Kaladhar B. Reddy; Gina L. Mangold; Atul K. Tandon; Toshiyuki Yoneda; Gregory R. Mundy; Asher Zilberstein; C. Kent Osborne

1992-01-01

220

Effect of organic acids on the growth and lipid accumulation of oleaginous yeast Trichosporon fermentans  

PubMed Central

Background Microbial lipids have drawn increasing attention in recent years as promising raw materials for biodiesel production, and the use of lignocellulosic hydrolysates as carbon sources seems to be a feasible strategy for cost-effective lipid fermentation with oleaginous microorganisms on a large scale. During the hydrolysis of lignocellulosic materials with dilute acid, however, various kinds of inhibitors, especially large amounts of organic acids, will be produced, which substantially decrease the fermentability of lignocellulosic hydrolysates. To overcome the inhibitory effects of organic acids, it is critical to understand their impact on the growth and lipid accumulation of oleaginous microorganisms. Results In our present work, we investigated for the first time the effect of ten representative organic acids in lignocellulosic hydrolysates on the growth and lipid accumulation of oleaginous yeast Trichosporon fermentans cells. In contrast to previous reports, we found that the toxicity of the organic acids to the cells was not directly related to their hydrophobicity. It is worth noting that most organic acids tested were less toxic than aldehydes to the cells, and some could even stimulate the growth and lipid accumulation at a low concentration. Unlike aldehydes, most binary combinations of organic acids exerted no synergistic inhibitory effects on lipid production. The presence of organic acids decelerated the consumption of glucose, whereas it influenced the utilization of xylose in a different and complicated way. In addition, all the organic acids tested, except furoic acid, inhibited the malic activity of T. fermentans. Furthermore, the inhibition of organic acids on cell growth was dependent more on inoculum size, temperature and initial pH than on lipid content. Conclusions This work provides some meaningful information about the effect of organic acid in lignocellulosic hydrolysates on the lipid production of oleaginous yeast, which is helpful for optimization of biomass hydrolysis processes, detoxified pretreatment of hydrolysates and lipid production using lignocellulosic materials. PMID:22260291

2012-01-01

221

Inhibition of tumour cell growth by carnosine: some possible mechanisms.  

PubMed

The naturally occurring dipeptide carnosine (?-alanyl-L-histidine) has been shown to inhibit, selectively, growth of transformed cells mediated, at least in part, by depleting glycolytic ATP levels. The mechanism(s) responsible has/have yet to be determined. Here, we discuss a number of probable and/or possible processes which could, theoretically, suppress glycolytic activity which would decrease ATP supply and generation of metabolic intermediates required for continued cell reproduction. Possibilities include effects on (i) glycolytic enzymes, (ii) metabolic regulatory activities, (iii) redox biology, (iv) protein glycation, (v) glyoxalase activity, (vi) apoptosis, (vii) gene expression and (viii) metastasis. It is possible, by acting at various sites that this pluripotent dipeptide may be an example of an endogenous "smart drug". PMID:24292217

Hipkiss, Alan R; Gaunitz, Frank

2014-02-01

222

Brazilin inhibits growth and induces apoptosis in human glioblastoma cells.  

PubMed

Brazilin, isolated from the methanol extract of the heart wood of Caesalpinia sappan, sensitizes cancer cells to apoptosis. Glioblastoma multiforme (GBM), which accounts for most cases of central nervous system malignancy, has a very poor prognosis and lacks effective therapeutic interventions. We, therefore, investigated the effects of different concentrations of and different periods of exposure to brazilin on cell proliferation and apoptosis in the glioma U87 cell line. Cell proliferation was investigated by MTT assays and growth curve analysis, apoptosis was assessed by FACS analysis and western blot studies. Brazilin showed dose-dependent inhibition of cell proliferation and induction of apoptosis in glioma cells. It also increased the ratio of cleaved poly-(ADP)-ribose polymerase and decreased the expression of caspase-3 and caspase-7. PMID:23429418

Lee, Dae-Young; Lee, Mi-Kyoung; Kim, Geum-Soog; Noh, Hyung-Jun; Lee, Min-Ho

2013-01-01

223

Inhibition of transforming growth factor-?-activated kinase-1 blocks cancer cell adhesion, invasion, and metastasis  

PubMed Central

Background: Tumour cell metastasis involves cell adhesion and invasion, processes that depend on signal transduction, which can be influenced by the tumour microenvironment. N-6 polyunsaturated fatty acids, found both in the diet and in response to inflammatory responses, are important components of this microenvironment. Methods: We used short hairpin RNA (shRNA) knockdown of TGF-?-activated kinase-1 (TAK1) in human tumour cells to examine its involvement in fatty acid-stimulated cell adhesion and invasion in vitro. An in vivo model of metastasis was developed in which cells, stably expressing firefly luciferase and either a control shRNA or a TAK1-specific shRNA, were injected into the mammary fat pads of mice fed diets, rich in n-6 polyunsaturated fatty acids. Tumour growth and spontaneous metastasis were monitored with in vivo and in situ imaging of bioluminescence. Results: Arachidonic acid activated TAK1 and downstream kinases in MDA-MB-435 breast cancer cells and led to increased adhesion and invasion. Knockdown of TAK1 blocked this activation and inhibited both cell adhesion and invasion in vitro. Tumour growth at the site of injection was not affected by TAK1 knockdown, but both the incidence and extent of metastasis to the lung were significantly reduced in mice injected with TAK1 knockdown cells compared with mice carrying control tumour cells. Conclusion: These data demonstrate the importance of TAK1 signalling in tumour metastasis in vivo and suggest an opportunity for antimetastatic therapies. PMID:22644295

Ray, D M; Myers, P H; Painter, J T; Hoenerhoff, M J; Olden, K; Roberts, J D

2012-01-01

224

Exposure to Asulox Inhibits the Growth of Mosses  

PubMed Central

Asulox is a herbicide used to control bracken. Its effects on mosses were investigated to ascertain whether exposure proved as detrimental as found in parallel studies on pteridophytes. Mature gametophytes of 18 mosses were exposed to a range of concentrations of Asulox under standard conditions and the effects on growth monitored. Plants were cut to a standard length, exposed to Asulox solution for 24 h, grown for 3 weeks and total elongation (main stem and branches) measured. EC50 values were calculated and species ranked according to sensitivity. The effects of exposure on total elongation were compared with those on main stem elongation alone. Under the conditions tested, the total elongation of all species was inhibited after exposure to Asulox. The amount of elongation observed after exposure was different for different species and inhibition of elongation occurred at different exposure concentrations. A single regression equation was not adequate to describe the dose response curves of all species tested. An ability to produce secondary branches may confer increased tolerance to Asulox exposure. It is concluded that mosses suffer detrimental effects after exposure to Asulox at concentrations similar to those that affect fern gametophytes such as bracken. PMID:12933364

ROWNTREE, J. K.; LAWTON, K. F.; RUMSEY, F. J.; SHEFFIELD, E.

2003-01-01

225

Inhibition of Fibroblast Growth Factor 19 Reduces Tumor Growth by Modulating B-Catenin Signaling  

Microsoft Academic Search

Fibroblast growth factors (FGF) play important roles in development, angiogenesis, and cancer. FGF19 uniquely binds to FGF receptor 4 (FGFR4). Our previous study has shown that FGF19 transgenic tumors have an activated Wnt-pathway phenotype. Wnt signaling is implicated in initiating or promoting FGF signaling in various cell types and organs. In this study, we examined whether FGF19 or inhibition of

Rama Pai; Debra Dunlap; Jing Qing; Iman Mohtashemi; Kathy Hotzel; Dorothy M. French

2008-01-01

226

Sulfasalazine inhibits the growth of primary brain tumors independent of nuclear factor-kappaB.  

PubMed

Nuclear factor-kappaB (NF-kappaB) is a pleiotropic transcription factor that generally enhances cellular resistance to apoptotic cell death. It has been shown to be constitutively active in some cancers and is being pursued as potential anticancer target. Sulfasalazine which is used clinically to treat Crohn's disease has emerged as a potential inhibitor of NF-kappaB and has shown promising results in two pre-clinical studies to target primary brain tumors, gliomas. Once digested, sulfasalazine is cleaved into sulfapyridine and 5-aminosalicylic acid (5-ASA; mesalamine) by colonic bacteria, and the latter, too, is reported to suppress NF-kappaB activity. We now show that glioma cells obtained from patient biopsies or glioma cell lines do not show significant constitutive NF-kappaB activation, unless exposed to inflammatory cytokines. This does not change when gliomas are implanted into the cerebrum of severe combined immun-deficient mice. Nevertheless, sulfasalazine but not its cleaved form 5-ASA caused a dose-dependent inhibition of glioma growth. This effect was entirely attributable to the inhibition of cystine uptake via the system x(c)(-) cystine-glutamate transporter. It could be mimicked by S-4-carboxy-phenylglycine (S-4-CPG) a more specific system x(c)(-) inhibitor, and lentiviral expression of a constitutively active form of IkappaB kinase b was unable to overcome the growth retarding effects of sulfasalazine or S-4-CPG. Both drugs inhibited cystine uptake causing a chronic depletion of intracellular GSH and consequently compromised cellular redox defense which stymied tumor growth. This data suggests that system x(c)(-) is a promising therapeutic target in gliomas and possibly other cancers and that it can be pharmacologically inhibited by Sulfasalazine, an FDA-approved drug. PMID:19457125

Chung, W Joon; Sontheimer, Harald

2009-07-01

227

Magnetic fluid hyperthermia inhibits the growth of breast carcinoma and downregulates vascular endothelial growth factor expression  

PubMed Central

The application of magnetic fluid hyperthermia (MFH) with nanoparticles has been shown to inhibit tumor growth in several animal models. However, the feasibility of using MFH in vivo to treat breast cancer is uncertain, and the mechanism is unclear. In the present study, it was observed that the intratumoral administration of MFH induced hyperthermia significantly in rats with Walker-265 breast carcinomas. The hyperthermia treatment with magnetic nanoparticles inhibited tumor growth in vivo and promoted the survival of the tumor-bearing rats. Furthermore, it was found that MFH treatment downregulated the protein expression of vascular endothelial growth factor (VEGF) in the tumor tissue, as observed by immunohistochemistry. MFH treatment also decreased the gene expression of VEGF and its receptors, VEGF receptor 1 and 2, and inhibited angiogenesis in the tumor tissues. Taken together, these results indicate that the application of MFH with nanoparticles is feasible for the treatment of breast carcinoma. The MFH-induced downregulation of angiogenesis may also contribute to the induction of an anti-tumor effect. PMID:24765139

WANG, GUIHUA; XU, DERONG; CHAI, QIN; TAN, XIAOLANG; ZHANG, YU; GU, NING; TANG, JINTIAN

2014-01-01

228

Corrosion inhibition of mild steel in sulfamic acid solution by S-containing amino acids  

Microsoft Academic Search

Rp, potentiodynamic polarization curves and EIS techniques were applied to study the effect of five S-containing amino acids\\u000a on the corrosion of mild steel in 5% sulfamic acid solution at 40 °C. The compounds are effective inhibitors and the inhibition\\u000a efficiency follow the order: N-acetylcysteine (ACC) > cysteine (RSH) > S-benzylcysteine (BzC) > cystine (RSSR) ? methionine (CH3SR). The inhibitors affect the anodic dissolution of steel by blocking the

M. S. Morad

2008-01-01

229

Synthesis of Protein and Ribonucleic Acid in a Psychrophile at Normal and Restrictive Growth Temperatures  

PubMed Central

A defined medium was capable of supporting the growth of a psychrophilic coccus over its growth temperature range, ?4 to 25 C. A rapid loss of viability occurred when exponential cells were transferred to growth-restricting temperatures above 25 C. Comparative studies of the chemistry of exponential-phase cells and cells exposed to supermaximum temperature indicated that this loss of viability is not due to temperature-induced membrane damage, inhibition of respiration or energy metabolism, or depletion of intracellular reserves. Moribund and dead cell populations showed an elevated level of intracellular adenosine-5?-triphosphate and amino acids—a finding reflected in the reduced rate of amino acid synthesis during the recovery of heat-shocked cells—and also leakage of degraded ribonucleic acid products into the medium. Incorporation studies indicated that loss of viability at 30 C was correlated with inhibition of protein synthesis, followed later by inhibition of ribonucleic acid synthesis. Deoxyribonucleic acid synthesis was unaffected by temperature above the maximum. PMID:5646626

Malcolm, Neil L.

1968-01-01

230

Fibroblast growth factor 7 inhibits cholesterol 7?-hydroxylase gene expression in hepatocytes.  

PubMed

Cholesterol 7?-hydroxylase (CYP7A1) is the initial and rate-limiting enzyme for bile acid synthesis. Transcription of the CYP7A1 gene is regulated by bile acids, nuclear receptors and cytokines. Fibroblast growth factor 7 (FGF7) secreted from activated hepatic stellate cells (HSC) during chronic liver fibrosis regulates hepatocyte survival and liver regeneration. In the carbon tetrachloride (CCl(4))-induced fibrotic mouse liver, we demonstrated that the expression of CYP7A1 was largely decreased while the expression of FGF7 was significantly increased. We further demonstrated that FGF7 inhibited CYP7A1 gene expression in hepatocytes. Knockdown study by short interfering RNA, kinase inhibition and phosphorylation assays revealed that the suppression of CYP7A1 expression by FGF7 was mediated by FGFR2 and its downstream JNK signaling cascade. The FGF7 neutralizing antibody restored CYP7A1 expression in Hep3B cells treated with conditioned medium from HSC. In summary, the data suggest that FGF7 is a novel regulator of CYP7A1 expression in hepatocytes and may prevent hepatocytes from accumulating toxic bile acids during liver injury and fibrosis. PMID:22713451

Sun, Zhichao; Yu, Xuemei; Wu, Weibin; Jia, Dongwei; Chen, Yinle; Ji, Lingling; Liu, Xijun; Peng, Xiaomin; Li, Yintao; Yang, Lili; Ruan, Yuanyuan; Gu, Jianxin; Ren, Shifang; Zhang, Songwen

2012-07-13

231

Rice Varietal Differences in Bioactive Bran Components for Inhibition of Colorectal Cancer Cell Growth  

PubMed Central

Rice bran chemical profiles differ across rice varieties and have not yet been analyzed for differential chemopreventive bioactivity. A diverse panel of 7 rice bran varieties was analyzed for growth inhibition of human colorectal cancer (CRC) cells. Inhibition varied from 0–99%, depending on the variety of bran used. Across varieties, total lipid content ranged 5–16%, individual fatty acids had 1.4 to 1.9 fold differences, vitamin E isoforms (?-, ?-, ?- tocotrienols and tocopherols) showed 1.3 to 15.2 fold differences, and differences in ?- oryzanol and total phenolics ranged between 100–275 ng/mg and 57–146 ng GAE/mg, respectively. Spearman correlation analysis was used to identify bioactive compounds implicated in CRC cell growth inhibitory activity. Total phenolics and ?- tocotrienol were positively correlated with reduced CRC cell growth (p < 0.05). Stoichiometric variation in rice bran components and differential effects on CRC viability merit further evaluation elucidate their role in dietary CRC chemoprevention. PMID:23790950

Forster, Genevieve M.; Raina, Komal; Kumar, Ajay; Kumar, Sushil; Agarwal, Rajesh; Chen, Ming-Hsuan; Bauer, John E.; McClung, Anna M.; Ryan, Elizabeth P.

2013-01-01

232

Inhibition of norsolorinic acid accumulation to Aspergillus parasiticus by marine actinomycetes  

NASA Astrophysics Data System (ADS)

Thirty-six strains of marine actinomycetes were isolated from a sample of marine sediment collected from the Yellow Sea and evaluated in terms of their inhibitory activity on the growth of Aspergillus parasiticus and the production of norsolorinic acid using dual culture plate assay and agar diffusion methods. Among them, three strains showed strong antifungal activity and were subsequently identified as Streptomyces sp. by 16S rRNA gene sequencing analysis. The supernatant from the fermentation of the MA01 strain was extracted sequentially with chloroform and ethyl acetate, and the activities of the extracts were determined by tip culture assay. The assay results show that both extracts inhibited mycelium growth and toxin production, and the inhibitory activities of the extracts increased as their concentrations increased. The results of this study suggest that marine actinomycetes are biologically important for the control of mycotoxins, and that these bacteria could be used as novel biopesticides against mycotoxins.

Yan, Peisheng; Shi, Cuijuan; Shen, Jihong; Wang, Kai; Gao, Xiujun; Li, Ping

2014-11-01

233

Promotion of plant growth by polymers of lactic acid  

Microsoft Academic Search

Polymers of L-lactic acid are shown to promote plant growth. Dry weight of duckweed (Lemna minor L.) and corn (Zea mays L) was more than doubled when plants were grown in media containing the dimer of L-lactic acid, L-lactoyllactic acid. Higher polymers were equally effective at increasing plant biomass. Monomeric lactic acid and polymers of D-lactic acid showed no biological

Alan M. Kinnersley; Taylor C. Scott; John H. Yopp; George H. Whitten

1990-01-01

234

MECHANISMS OF FLUID SHEAR-INDUCED INHIBITION OF POPULATION GROWTH IN A RED-TIDE DINOFLAGELLATE  

EPA Science Inventory

Net population growth of some dinoflagellates is inhibited by fluid shear at shear stresses comparable with those generated during oceanic turbulence. Decreased net growth may occur through lowered cell division, increased mortality, or both. The dominant mechanism under various ...

235

Ursolic Acid Inhibits Proliferation and Induces Apoptosis of Cancer Cells In Vitro and In Vivo  

PubMed Central

The aims of the study are to explore the effect of ursolic acid (UA) on the growth of gastric cancer cell line BGC-803 and hepatocellular cancer cell H22 xenograft and to understand the mechanism. UA inhibits growth of BGC-803 cells in vitro in dose-dependent and time-dependent manner. Treated with UA in vivo, tumor cells can be arrested to G0/G1 stage. The apoptotic rate was significantly increased in tumor cells treated with UA both in vitro and in vivo. DNA fragmentation was found in BGC-803 cells exposed to UA. UA activated caspase-3, -8, and -9 and down regulated expression of Bcl-2 in BGC-803 cells. The expression of caspase-3 and -8 was elevated in tumor cells from xenograft treated with UA. 18F-FLT PET-CT imaging confirmed tumor model and UA effectiveness. Our results indicated that UA inhibits growth of tumor cells both in vitro and in vivo by decreasing proliferation of cells and inducing apoptosis. PMID:21716649

Wang, Xuemei; Zhang, Fan; Yang, Ling; Mei, Ying; Long, Hai; Zhang, Xiaowen; Zhang, Jialing; Qimuge-Suyila; Su, Xiulan

2011-01-01

236

Caffeic Acid phenethyl ester inhibits epithelial-mesenchymal transition of human pancreatic cancer cells.  

PubMed

Background. This study aimed to investigate the effect of propolis component caffeic acid phenethyl ester (CAPE) on epithelial-mesenchymal transition (EMT) of human pancreatic cancer cells and the molecular mechanisms underlying these effects. Methods. The transforming growth factor ? (TGF-?-) induced EMT in human pancreatic PANC-1 cancer cells was characterized by observation of morphology and the expression of E-cadherin and vimentin by western blotting. The migration potential was estimated with wound closure assay. The expression of transcriptional factors was measured by quantitative RT-PCR and immunocytochemistry staining. The orthotopic pancreatic cancer xenograft model was used for in vivo assessment. Results. The overexpression of vimentin was attenuated by CAPE, and the alteration in morphology from polygonal to spindle shape was partially reversed by CAPE. Furthermore, CAPE delayed the TGF-?-stimulated migration potential. CAPE treatment did not reduce the expression levels of Smad 2/3, Snail 1, and Zeb 1 but inhibited the expression of transcriptional factor Twist 2. By using an orthotopic pancreatic cancer model, CAPE suppressed the expression of Twist 2 and growth of PANC-1 xenografts without significant toxicity. Conclusion. CAPE could inhibit the orthotopic growth and EMT of pancreatic cancer PANC-1 cells accompanied by downregulation of vimentin and Twist 2 expression. PMID:23662124

Chen, Ming-Jen; Shih, Shou-Chuan; Wang, Horng-Yuan; Lin, Ching-Chung; Liu, Chia-Yuan; Wang, Tsang-En; Chu, Cheng-Hsin; Chen, Yu-Jen

2013-01-01

237

Idarubicin inhibits the growth of bacteria and yeasts in an automated blood culture system  

Microsoft Academic Search

The effect of anti-neoplastic agents on the growth of microorganisms was studied in vitro using aerobic BacT\\/Alert standard\\u000a and FAN bottles as the culture media. A 50% longer incubation period to detect microbial growth compared to the control group\\u000a was interpreted as growth inhibition. Idarubicin inhibited the growth of all of the five gram-positive cocci, one of five\\u000a gram-negative rods

U. Kinnunen; H. Syrjälä; P. Koistinen; M. Koskela

2009-01-01

238

Climate Dependency of Tree Growth Suppressed by Acid Deposition  

E-print Network

the onset of high acid deposition rates are available from only two studies worldwide (10, 11Climate Dependency of Tree Growth Suppressed by Acid Deposition Effects on Soils in Northwest and boreal forests has been proposed as a direct consequence of a warming climate. Acid deposition effects

Lapenas, Andrei G.

239

Fibroblast growth factor 7 inhibits cholesterol 7{alpha}-hydroxylase gene expression in hepatocytes  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer FGF7 strongly and rapidly down-regulates the expression of CYP7A1 in hepatocytes. Black-Right-Pointing-Pointer FGF7 suppresses the expression of CYP7A1 via FGFR2 and downstream JNK activation. Black-Right-Pointing-Pointer Blocking FGF7 abrogates HSC-induced inhibition of CYP7A1 expression in hepatocytes. -- Abstract: Cholesterol 7{alpha}-hydroxylase (CYP7A1) is the initial and rate-limiting enzyme for bile acid synthesis. Transcription of the CYP7A1 gene is regulated by bile acids, nuclear receptors and cytokines. Fibroblast growth factor 7 (FGF7) secreted from activated hepatic stellate cells (HSC) during chronic liver fibrosis regulates hepatocyte survival and liver regeneration. In the carbon tetrachloride (CCl{sub 4})-induced fibrotic mouse liver, we demonstrated that the expression of CYP7A1 was largely decreased while the expression of FGF7 was significantly increased. We further demonstrated that FGF7 inhibited CYP7A1 gene expression in hepatocytes. Knockdown study by short interfering RNA, kinase inhibition and phosphorylation assays revealed that the suppression of CYP7A1 expression by FGF7 was mediated by FGFR2 and its downstream JNK signaling cascade. The FGF7 neutralizing antibody restored CYP7A1 expression in Hep3B cells treated with conditioned medium from HSC. In summary, the data suggest that FGF7 is a novel regulator of CYP7A1 expression in hepatocytes and may prevent hepatocytes from accumulating toxic bile acids during liver injury and fibrosis.

Sun, Zhichao [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China)] [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China); Yu, Xuemei [Department of Endocrinology, Fengxian Central Hospital, Shanghai (China)] [Department of Endocrinology, Fengxian Central Hospital, Shanghai (China); Wu, Weibin; Jia, Dongwei; Chen, Yinle; Ji, Lingling; Liu, Xijun; Peng, Xiaomin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China)] [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China); Li, Yintao [Institute of Endocrinology and Diabetology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai (China)] [Institute of Endocrinology and Diabetology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai (China); Yang, Lili [Department of Endocrinology, Fengxian Central Hospital, Shanghai (China)] [Department of Endocrinology, Fengxian Central Hospital, Shanghai (China); Ruan, Yuanyuan; Gu, Jianxin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China)] [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China); Ren, Shifang, E-mail: renshifang@fudan.edu.cn [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China)] [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China); Zhang, Songwen, E-mail: songwenzhang@fudan.edu.cn [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China)] [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China)

2012-07-13

240

Novel therapeutic approach: organic arsenical (melarsoprol) alone or with all-trans-retinoic acid markedly inhibit growth of human breast and prostate cancer cells in vitro and in vivo  

Microsoft Academic Search

The organic arsenical known as melarsoprol (Mel-B) is used to treat African trypanosomiasis. Recently, another arsenical, As2O3 was shown to be effective in treatment of acute promyelocytic leukaemia. We have investigated the anti-tumour activities of Mel-B either with or without all-trans-retinoic acid (ATRA) using the MCF-7 human breast cancer cells, as well as the PC-3 and DU 145 human prostate

K Koshiuka; E Elstner; E Williamson; J W Said; Y Tada; H P Koeffler

2000-01-01

241

Inhibition of Listeria monocytogenes by propionic acid-based ingredients in cured deli-style Turkey.  

PubMed

Listeria monocytogenes growth can be controlled on ready-to-eat meats through the incorporation of antimicrobial ingredients into the formulation or by postlethality kill steps. However, alternate approaches are needed to provide options that reduce sodium content but maintain protection against pathogen growth in meats after slicing. The objective of this study was to determine the inhibition of L. monocytogenes by propionic acid-based ingredients in high-moisture, cured turkey stored at 4 or 7°C. Six formulations of sliced, cured (120 ppm of NaNO2 ), deli-style turkey were tested, including control without antimicrobials, 3.2% lactate-diacetate blend (LD), 0.4% of a liquid propionate-benzoate-containing ingredient, or 0.3, 0.4, and 0.5% of a liquid propionate-containing ingredient. Products were inoculated with 5 log CFU L. monocytogenes per 100-g package (3 log CFU/ml rinsate), vacuum-sealed, and stored at 4 or 7°C for up to 12 weeks; and populations were enumerated by plating on modified Oxford agar. As expected, the control without antimicrobials supported rapid growth, with >2 log average per ml rinsate increase within 4 weeks of storage at 4°C, whereas growth was observed at 6 weeks for the LD treatment. For both replicate trials, all treatments that contained liquid propionate or propionate-benzoate limited L. monocytogenes growth to an increase of <1 log through 9 weeks storage at 4°C. Sporadic growth (>1-log increase) was observed in individual samples for all propionate-containing treatments at weeks 10, 11, and 12. As expected, L. monocytogenes grew more rapidly when products were stored at 7°C, but trends in relative inhibition were similar to those observed at 4°C. These results verify that propionate-based ingredients inhibit growth of L. monocytogenes on sliced, high-moisture, cured turkey and can be considered as an alternative to reduce sodium-based salts while maintaining food safety. PMID:24290685

Glass, Kathleen A; McDonnell, Lindsey M; Von Tayson, Roxanne; Wanless, Brandon; Badvela, Mani

2013-12-01

242

Caffeic acid inhibits in vitro rooting in mung bean [ Vigna radiata (L.) Wilczek] hypocotyls by inducing oxidative stress  

Microsoft Academic Search

Caffeic acid (CA), which is ubiquitously present in plants, is a potent phytotoxin affecting plant growth and physiology.\\u000a The aim of our study was to investigate whether CA-induced inhibition of adventitious root formation (ARF) in mung bean {Vigna radiata (L.) Wilczek [Phaseolus aureus Roxb.]} involves the induction of conventional stress responses. The effect of CA (0–1000 ?M) on ARF in mung

Harminder Pal Singh; Shalinder Kaur; Daizy R. Batish; Ravinder Kumar Kohli

2009-01-01

243

Salicylic acid inhibits the biosynthesis of ethylene in detached rice leaves  

Microsoft Academic Search

The effects of salicylic acid (SA) on ethylene biosynthesis in detached rice leaves were investigated. SA at pH 3.5 effectively inhibited ethylene production within 2 h of its application. It inhibited the conversion of ACC to ethylene, but did not affect the levels of ACC and conjugated ACC. Thus, the inhibitory effect of SA resulted from the inhibition of both

Y F. Huang; C. T. Chen; C. H. Kao

1993-01-01

244

Mechanical and acid neutralizing properties and bacteria inhibition of amorphous calcium phosphate dental nanocomposite  

PubMed Central

Dental composites do not hinder bacteria colonization and plaque formation. Caries at the restoration margins is a frequent reason for replacement of existing restorations, which accounts for 50 to 70% of all restorations. The objectives of this study were to examine the filler level effect on nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) and investigate the load-bearing and acid-neutralizing properties and bacteria inhibition. NACP with 116-nm particle size were synthesized via a spray-drying technique and incorporated into a resin. Flexural strength of nanocomposite with 10 to 30% NACP fillers matched the strength of a commercial hybrid composite (p > 0.1). Nanocomposite with 40% NACP matched the strength of a microfill composite, which was 2-fold that of a resin-modified glass ionomer. Nanocomposite with 40% NACP neutralized a lactic acid solution of pH 4 by rapidly increasing the pH to 5.69 in 10 min. In contrast, the commercial controls had pH staying at near 4. Using Streptoccocus mutans, an agar disk-diffusion test showed no inhibition zone for commercial controls. In contrast, the inhibition zone was (2.5 ± 0.7) mm for nanocomposite with 40% NACP. Crystal violet staining showed that S. mutans coverage on nanocomposite was 1/4 that on commercial composite. In conclusion, novel calcium–phosphate nanocomposite matched the mechanical properties of commercial composite and rapidly neutralized lactic acid of pH 4. The nanocomposite appeared to moderately reduce the S. mutans growth, and further study is needed to obtain strong antimicrobial properties. The new nanocomposite may have potential to reduce secondary caries and restoration fracture, two main challenges facing tooth cavity restorations. PMID:21504057

Moreau, Jennifer L.; Sun, Limin; Chow, Laurence C.; Xu, Hockin H. K.

2012-01-01

245

Inhibition of Listeria monocytogenes and Salmonella by combinations of oriental mustard, malic acid, and EDTA.  

PubMed

The antimicrobial activities of oriental mustard extract alone or combined with malic acid and EDTA were investigated against Salmonella spp. or Listeria monocytogenes at different temperatures. Five strain Salmonella or L. monocytogenes cocktails were separately inoculated in Brain Heart Infusion broth containing 0.5% (w/v) aqueous oriental mustard extract and incubated at 4 °C to 21 °C for 21 d. For inhibitor combination tests, Salmonella Typhimurium 02:8423 and L. monocytogenes 2-243 were individually inoculated in Mueller Hinton broth containing the mustard extract with either or both 0.2% (w/v) malic acid and 0.2% (w/v) EDTA and incubated at 10 °C or 21 °C for 10 to 14 d. Mustard extract inhibited growth of the L. monocytogenes cocktail at 4 °C up to 21 d (2.3 log10 CFU/mL inhibition) or at 10 °C for 7 d (2.4 log10 CFU/mL inhibition). Salmonella spp. viability was slightly, but significantly reduced by mustard extract at 4 °C by 21 d. Although hydrolysis of sinigrin in mustard extract by both pathogens was 2 to 6 times higher at 21 °C than at 4 °C to 10 °C, mustard was not inhibitory at 21 °C, perhaps because of the instability of its hydrolysis product (allyl isothiocyanate). At 21 °C, additive inhibitory effects of mustard extract with EDTA or malic acid led to undetectable levels of S. Typhimurium and L. monocytogenes by 7 d and 10 d, respectively. At 10 °C, S. Typhimurium was similarly susceptible, but combinations of antimicrobials were not more inhibitory to L. monocytogenes than the individual agents. PMID:24649979

Olaimat, Amin N; Holley, Richard A

2014-04-01

246

Corrosion inhibition of mild steel by Datura metel in acidic medium  

Microsoft Academic Search

Purpose – To evaluate the corrosion inhibition potential of Datura metel in acid medium on mild steel (MS) with a view to develop green corrosion inhibitors. Design\\/methodology\\/approach – Acid extract of the D. metel was studied for its corrosion inhibitive effect by electrochemical and weight loss methods. Using weight loss measurement data, an attempt has been made to probe the

M. G. Sethuraman; P. Bothi Raja

2005-01-01

247

Ascorbic Acid Inhibition of Candida albicans Hsp90-Mediated Morphogenesis Occurs via the Transcriptional Regulator Upc2.  

PubMed

Morphogenetic transitions of the opportunistic fungal pathogen Candida albicans are influenced by temperature changes, with induction of filamentation upon a shift from 30 to 37°C. Hsp90 was identified as a major repressor of an elongated cell morphology at low temperatures, as treatment with specific inhibitors of Hsp90 results in elongated growth forms at 30°C. Elongated growth resulting from a compromised Hsp90 is considered neither hyphal nor pseudohyphal growth. It has been reported that ascorbic acid (vitamin C) interferes with the yeast-to-hypha transition in C. albicans. In the present study, we show that ascorbic acid also antagonizes the morphogenetic change caused by hampered Hsp90 function. Further analysis revealed that Upc2, a transcriptional regulator of genes involved in ergosterol biosynthesis, and Erg11, the target of azole antifungals, whose expression is in turn regulated by Upc2, are required for this antagonism. Ergosterol levels correlate with elongated growth and are reduced in cells treated with the Hsp90 inhibitor geldanamycin (GdA) and restored by cotreatment with ascorbic acid. In addition, we show that Upc2 appears to be required for ascorbic acid-mediated inhibition of the antifungal activity of fluconazole. These results identify Upc2 as a major regulator of ascorbic acid-induced effects in C. albicans and suggest an association between ergosterol content and elongated growth upon Hsp90 compromise. PMID:25084864

Van Hauwenhuyse, Frédérique; Fiori, Alessandro; Van Dijck, Patrick

2014-10-01

248

?-Lipoic acid-induced inhibition of proliferation and met phosphorylation in human non-small cell lung cancer cells.  

PubMed

?-Lipoic acid (?-LA), a naturally occurring anti-oxidant and co-factor for metabolic enzymes, suppresses the growth of different types of tumor cells. The mechanisms that are responsible for these results, however, remain to be elucidated. In the present study, we investigated the effects of ?-LA on the proliferation and activation status of definitive receptor tyrosine kinases, epidermal growth factor receptor (EGFR) and Met/hepatocyte growth factor (HGF) receptor, in gefitinib-sensitive human non-small cell lung cancer cells harboring EGFRs with an activating mutation. The enantiomers R-?-LA and S-?-LA suppressed cell proliferation and increased the level of reactive oxygen species in HCC-827 and PC-9 human non-small cell lung cancer cells in an indistinguishable dose-dependent fashion. A phospho-receptor tyrosine kinase array and cell cycle analysis indicated that ?-LA decreased tyrosine phosphorylation levels of EGFR, ErbB2, and Met, and this was associated with an inhibition in the cell-cycle transition from the G1 phase to the S phase without inducing apoptosis. Gefitinib, an inhibitor for EGFR tyrosine kinase, inhibited EGFR tyrosine phosphorylation/activation and proliferation of the cells. Instead, the addition of HGF induced Met tyrosine phosphorylation, and this was associated with a resistance to gefitinib-induced growth inhibition, which meant a gain in proliferative ability. In the presence of gefitinib and HGF, the addition of ?-LA suppressed Met tyrosine phosphorylation, and this was associated with an inhibition in cell growth. These results suggest that the suppression of tyrosine phosphorylation/activation of growth factor receptors that is critical for the proliferation of human non-small cell lung cancer cells is a mechanism by which ?-LA exerts growth inhibition for cancer cells. PMID:23507559

Michikoshi, Hiromitsu; Nakamura, Takahiro; Sakai, Katsuya; Suzuki, Yoshinori; Adachi, Eri; Matsugo, Seiichi; Matsumoto, Kunio

2013-07-28

249

A new in vitro model of the glial scar inhibits axon growth  

PubMed Central

Astrocytes respond to central nervous system (CNS) injury with reactive astrogliosis and participate in the formation of the glial scar, an inhibitory barrier for axonal regeneration. Little is known about the injury-induced mechanisms underlying astrocyte reactivity and subsequent development of an axon-inhibitory scar. We combined two key aspects of CNS injury, mechanical trauma and co-culture with meningeal cells, to produce an in vitro model of the scar from cultures of highly differentiated astrocytes. Our model displayed widespread morphological signs of astrocyte reactivity, increases in expression of glial fibrillary acidic protein (GFAP), and accumulation of GFAP in astrocytic processes. Expression levels of scar-associated markers phosphacan, neurocan and tenascins were also increased. Importantly, neurite growth from various CNS neuronal populations was significantly reduced when neurons were seeded on the scar-like cultures, compared to growth on cultures of mature astrocytes. Quantification of neurite growth parameters on the scar model demonstrated significant reductions in neuronal adhesion and neurite lengths. Interestingly, neurite outgrowth of postnatal neurons was reduced to a greater extent than that of embryonic neurons, and outgrowth inhibition varied among neuronal populations. Scar-like reactive sites and neurite-inhibitory patches were found throughout these cultures, creating a patchwork of growth-inhibitory areas mimicking a CNS injury site. Thus, our model showed relevant aspects of scar formation and produced widespread inhibition of axonal regeneration; it should be useful both for examining mechanisms underlying scar formation and to assess various treatments for their potential to improve regeneration after CNS injury. PMID:18618667

Wanner, Ina B.; Deik, Andres; Torres, Miguel; Rosendahl, Andrew; Neary, Joseph T.; Lemmon, Vance P.; Bixby, John L.

2011-01-01

250

Growth inhibition and growth stimulation by estradiol of estrogen receptor transfected human breast epithelial cell lines involve different pathways  

Microsoft Academic Search

Epidermal growth factor (EGF) and estradiol (E2) are important mitogens in breast epithelial cells, and expression of epidermal growth factor receptor (EGFR) and estrogen receptor (ER) is often inversely correlated in human breast cancer cells. Stable transfection of ER-negative cells with ER cDNA is not sufficient to restore E2-mediated growth stimulation, on the contrary, E2 often inhibits growth of ER-transfected

Betina K. Lundholt; Per Briand; Anne E. Lykkesfeldt

2001-01-01

251

Specific and Slow Inhibition of the Kir2.1 K+ Channel by Gambogic Acid*  

PubMed Central

Although Kir2.1 channels are important in the heart and other excitable cells, there are virtually no specific drugs for this K+ channel. In search of Kir2.1 modulators, we screened a library of 720 naturally occurring compounds using a yeast strain in which mammalian Kir2.1 enables growth at low [K+]. One of the identified compounds, gambogic acid (GA), potently (EC50 ? 100 nm) inhibited Kir2.1 channels in mammalian cells when applied chronically for 3 h. This potent and slow inhibition was not seen with Kv2.1, HERG or Kir1.1 channels. However, acutely applied GA acted as a weak (EC50 = ?10 ?m) non-selective K+ channel blocker. Intracellular delivery of GA via a patch pipette did not potentiate the acute effect of GA on Kir2.1, showing that slow uptake is not responsible for the delayed, potent effect. Immunoblots showed that total Kir2.1 protein expression was not altered by GA. Similarly, immunostaining of intact cells expressing Kir2.1 with an extracellular epitope tag demonstrated that GA does not affect Kir2.1 surface expression. However, the 3-h treatment with GA caused redistribution of Kir2.1 and Kv2.1 from the Triton X-100-insoluble to the Triton X-100-soluble membrane fraction. Thus, GA changes the K+ channel membrane microenvironment resulting in potent, specific, and slow acting inhibition of Kir2.1 channels. PMID:19366693

Zaks-Makhina, Elena; Li, Hui; Grishin, Anatoly; Salvador-Recatala, Vicenta; Levitan, Edwin S.

2009-01-01

252

Identification of organic acids in Cichorium intybus inhibiting virulence-related properties of oral pathogenic bacteria.  

PubMed

The low molecular mass (LMM) extract of Cichorium intybus var. silvestre (red chicory) has been shown to inhibit virulence-linked properties of oral pathogens including Streptococcus mutans, Actinomyces naeslundii and Prevotella intermedia. In the present study HPLC-DAD-ESI/MS(2) was used to investigate the compounds contained in this extract for their anti-virulence activity. The extract contained a number of components, including oxalic, succinic, shikimic and quinic acids, which interfere with the growth and virulence traits (i.e., biofilm formation, adherence to epithelial cells and hydroxyapatite) of oral pathogens involved in gingivitis and tooth decay. Succinic and quinic acid seem to be the most potent, mainly by interfering with the ability of oral pathogens to form biofilms (either through inhibition of their development or promotion of their disruption). Our findings suggest that one or more of these compounds may modulate plaque formation in vivo, which is a prerequisite for the development of both caries and gingivitis. PMID:23411301

Papetti, Adele; Mascherpa, Dora; Carazzone, Chiara; Stauder, Monica; Spratt, David A; Wilson, Michael; Pratten, Jonathan; Ciric, Lena; Lingström, Peter; Zaura, Egija; Weiss, Ervin; Ofek, Itzak; Signoretto, Caterina; Pruzzo, Carla; Gazzani, Gabriella

2013-06-01

253

Inhibition of uropathogenic biofilm growth on silicone rubber in human urine by lactobacilli – a teleologic approach  

Microsoft Academic Search

The ability of three Lactobacillus strains to inhibit the adhesion and growth of naturally occurring uropathogens on silicone rubber was investigated in human\\u000a urine. The importance of biosurfactant production by Lactobacillus in discouraging uropathogen growth was determined in relation to the binding affinities of the lactobacilli for silicone\\u000a rubber. L. fermentum B54 markedly inhibited uropathogen growth on the silicone rubber

Martine M. C. Velraeds; Betsy van de Belt-Gritter; Henk J. Busscher; Gregor Reid; Henny C. van der Mei

2000-01-01

254

3,5-Dihydroxybenzoic acid, a specific agonist for hydroxycarboxylic acid 1, inhibits lipolysis in adipocytes.  

PubMed

Niacin raises high-density lipoprotein and lowers low-density lipoprotein through the activation of the ?-hydroxybutyrate receptor hydroxycarboxylic acid 2 (HCA2) (aka GPR109a) but with an unwanted side effect of cutaneous flushing caused by vascular dilation because of the stimulation of HCA2 receptors in Langerhans cells in skin. HCA1 (aka GPR81), predominantly expressed in adipocytes, was recently identified as a receptor for lactate. Activation of HCA1 in adipocytes by lactate results in the inhibition of lipolysis, suggesting that agonists for HCA1 may be useful for the treatment of dyslipidemia. Lactate is a metabolite of glucose, suggesting that HCA1 may also be involved in the regulation of glucose metabolism. The low potency of lactate to activate HCA1, coupled with its fast turnover rate in vivo, render it an inadequate tool for studying the biological role of lactate/HCA1 in vivo. In this article, we demonstrate the identification of 3-hydroxybenzoic acid (3-HBA) as an agonist for both HCA2 and HCA1, whereas 3,5-dihydroxybenzoic acid (3,5-DHBA) is a specific agonist for only HCA1 (EC(50) ?150 ?M). 3,5-DHBA inhibits lipolysis in wild-type mouse adipocytes but not in HCA1-deficient adipocytes. Therefore, 3,5-DHBA is a useful tool for the in vivo study of HCA1 function and offers a base for further HCA1 agonist design. Because 3-HBA and 3,5-DHBA are polyphenolic acids found in many natural products, such as fruits, berries, and coffee, it is intriguing to speculate that other heretofore undiscovered natural substances may have therapeutic benefits. PMID:22434674

Liu, Changlu; Kuei, Chester; Zhu, Jessica; Yu, Jingxue; Zhang, Li; Shih, Amy; Mirzadegan, Taraneh; Shelton, Jonathan; Sutton, Steven; Connelly, Margery A; Lee, Grace; Carruthers, Nicholas; Wu, Jiejun; Lovenberg, Timothy W

2012-06-01

255

Changes in free amino acid, phenolic, chlorophyll, carotenoid, and glycoalkaloid contents in tomatoes during 11 stages of growth and inhibition of cervical and lung human cancer cells by green tomato extracts.  

PubMed

Tomato ( Solanum lycopersicum ) plants synthesize nutrients, pigments, and secondary metabolites that benefit nutrition and human health. The concentrations of these compounds are strongly influenced by the maturity of the tomato fruit on the vine. Widely consumed Korean tomatoes of the variety Doturakworld were analyzed for changes in the content of free amino acids, phenolic compounds, chlorophylls, carotenoids, and glycoalkaloids at 11 stages (S1-S11) of ripeness. The results show that (a) the total content (in mg/100 g of FW) of the free amino acids and other nitrogen-containing compounds in the extracts ranged from about 41 to 85 in the green tomato extracts S1-S7 and then increased to 251 (S9) in the red extracts, followed by a decrease to 124 in S11 red extracts; (b) the total initial concentration and composition of up to 12 phenolic compounds of approximately 2000 microg/100 g of FW varied throughout the ripening process, with the quantity decreasing and the number of individual compounds increasing in the red tomato; (c) chlorophyll a and b content of tomatoes harvested during S1 was 5.73 mg/100 g of fresh pericarp and then decreased continuously to 1.14 mg/100 g for S11; (d) the concentration (in mg/100 g of FW) of lycopene in the S8 red extract of 0.32 increased to 1.27 in S11; and (e) tomatoes harvested during S1 contained 48.2 mg of dehydrotomatine/100 g of FW, and this value continually decreased to 1.5 in S7, with no detectable levels in S8-S11. The corresponding alpha-tomatine content decreased from S1 (361) to S8 (13.8). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell assay IC(50) values showed that Hel299 lung cells, A549 lung cancer cells, and HeLa cervical carcinoma cells were highly susceptible to inactivation by glycoalkaloid-rich green tomato extracts. Chang normal liver cells and U937 lymphoma cells were less susceptible. The possible significance of the results for plant physiology and the diet is discussed. PMID:20560602

Choi, Suk-Hyun; Lee, Sang-Hwa; Kim, Hyun-Jeong; Lee, In-Seon; Kozukue, Nobuyuki; Levin, Carol E; Friedman, Mendel

2010-07-14

256

Acetate-Mediated Growth Inhibition in Sterol 14?-Demethylation-Deficient Cells of Candida albicans  

PubMed Central

Candida albicans is a fungus thought to be viable in the presence of a deficiency in sterol 14?-demethylation. We showed in a strain of this species that the deficiency, caused either by a mutation or by an azole antifungal agent, made the cells susceptible to growth inhibition by acetate included in the culture medium. Studies with a mutant demonstrated that the inhibition was complete at a sodium acetate concentration of 0.24 M (20 g/liter) and was evident even at a pH of 8, the latter result indicating the involvement of acetate ions rather than the undissociated form of acetic acid. In fluconazole-treated cells, sterol profiles determined by thin-layer chromatography revealed that the minimum sterol 14?-demethylation-inhibitory concentrations (MDICs) of the drug, thought to be the most important parameter for clinical purposes, were practically identical in the media with and without 0.24 M acetate and were equivalent to the MIC in the acetate-supplemented medium. The acetate-mediated growth inhibition of azole-treated cells was confirmed with two additional strains of C. albicans and four different agents, suggesting the possibility of generalization. From these results, it was surmised that the acetate-containing medium may find use in azole susceptibility testing, for which there is currently no method capable of measuring MDICs directly for those fungi whose viability is not lost as a result of sterol 14?-demethylation deficiency. Additionally, the acetate-supplemented agar medium was found to be useful in detecting reversions from sterol 14?-demethylation deficiency to proficiency. PMID:9869573

Shimokawa, Osamu; Nakayama, Hiroaki

1999-01-01

257

Antisense Inhibition of the Iron-Sulphur Subunit of Succinate Dehydrogenase Enhances Photosynthesis and Growth in Tomato via an Organic Acid-Mediated Effect on Stomatal Aperture[W][OA  

PubMed Central

Transgenic tomato (Solanum lycopersicum) plants expressing a fragment of the Sl SDH2-2 gene encoding the iron sulfur subunit of the succinate dehydrogenase protein complex in the antisense orientation under the control of the 35S promoter exhibit an enhanced rate of photosynthesis. The rate of the tricarboxylic acid (TCA) cycle was reduced in these transformants, and there were changes in the levels of metabolites associated with the TCA cycle. Furthermore, in comparison to wild-type plants, carbon dioxide assimilation was enhanced by up to 25% in the transgenic plants under ambient conditions, and mature plants were characterized by an increased biomass. Analysis of additional photosynthetic parameters revealed that the rate of transpiration and stomatal conductance were markedly elevated in the transgenic plants. The transformants displayed a strongly enhanced assimilation rate under both ambient and suboptimal environmental conditions, as well as an elevated maximal stomatal aperture. By contrast, when the Sl SDH2-2 gene was repressed by antisense RNA in a guard cell–specific manner, changes in neither stomatal aperture nor photosynthesis were observed. The data obtained are discussed in the context of the role of TCA cycle intermediates both generally with respect to photosynthetic metabolism and specifically with respect to their role in the regulation of stomatal aperture. PMID:21307286

Araujo, Wagner L.; Nunes-Nesi, Adriano; Osorio, Sonia; Usadel, Bjorn; Fuentes, Daniela; Nagy, Reka; Balbo, Ilse; Lehmann, Martin; Studart-Witkowski, Claudia; Tohge, Takayuki; Martinoia, Enrico; Jordana, Xavier; DaMatta, Fabio M.; Fernie, Alisdair R.

2011-01-01

258

Inhibition of Ascorbate Peroxidase by Salicylic Acid and 2,6- Dichloroisonicotinic Acid, Two Inducers of Plant Defense Responses  

Microsoft Academic Search

In recent years, it has become apparent that salicylic acid (SA) plays an important role in plant defense responses to pathogen attack. Previous studies have suggested that one of SA's mechanisms of action is the inhibition of catalase, resulting in elevated levels of H_2 O_2, which activate defense-related genes. Here we demonstrate that SA also inhibits ascorbate peroxidase (APX), the

Jorg Durner; Daniel F. Klessig

1995-01-01

259

Proximity-dependent inhibition of growth of Mannheimia haemolytica by Pasteurella multocida.  

PubMed

Mannheimia haemolytica, Pasteurella multocida, and Bibersteinia trehalosi have been identified in the lungs of pneumonic bighorn sheep (BHS; Ovis canadensis). Of these pathogens, M. haemolytica has been shown to consistently cause fatal pneumonia in BHS under experimental conditions. However, M. haemolytica has been isolated by culture less frequently than the other bacteria. We hypothesized that the growth of M. haemolytica is inhibited by other bacteria in the lungs of BHS. The objective of this study was to determine whether P. multocida inhibits the growth of M. haemolytica. Although in monoculture both bacteria exhibited similar growth characteristics, in coculture with P. multocida there was a clear inhibition of growth of M. haemolytica. The inhibition was detected at mid-log phase and continued through the stationary phase. When cultured in the same medium, the growth of M. haemolytica was inhibited when both bacteria were separated by a membrane that allowed contact (pore size, 8.0 ?m) but not when they were separated by a membrane that limited contact (pore size, 0.4 ?m). Lytic bacteriophages or bactericidal compounds could not be detected in the culture supernatant fluid from monocultures of P. multocida or from P. multocida-M. haemolytica cocultures. These results indicate that P. multocida inhibits the growth of M. haemolytica by a contact- or proximity-dependent mechanism. If the inhibition of growth of M. haemolytica by P. multocida occurs in vivo as well, it could explain the inconsistent isolation of M. haemolytica from the lungs of pneumonic BHS. PMID:22798357

Bavananthasivam, Jegarubee; Dassanayake, Rohana P; Kugadas, Abirami; Shanthalingam, Sudarvili; Call, Douglas R; Knowles, Donald P; Srikumaran, Subramaniam

2012-09-01

260

Action spectra for the inhibition of growth in radish hypocotyls  

Microsoft Academic Search

In etiolated seedlings of Raphanus sativus L. the inhibition of hypocotyl elongation by continuous light showed a major bimodal peak of action in the red and far-red, and two minor peaks in the blue regions of the spectrum. It is argued that, under conditions of prolonged irradiation, phytochrome is the pigment controlling the inhibition of hypocotyl elongation by red and

Ann M. Jose; Daphne Vince-Prue

1977-01-01

261

Heptelidic acid, a sesquiterpene lactone, inhibits Etoposide-induced apoptosis in human leukemia U937 cells.  

PubMed

In the course of screening for substances that inhibit etoposide (10 microg/ml)-induced apoptosis in human leukemia U937 cells, fungal strain F000120, which exhibits potent inhibitory activity, was selected. The active compound was purified from an ethyl acetate extract of the microorganism by Sep-pak C18 column chromatography and HPLC, and was identified as heptelidic acid (koningic acid) by spectroscopic methods. This compound inhibited caspase- 3 induction in U937 cells with an IC(50) value of 40 microM after 8 h of etoposide treatment. Fluorescent dye staining with acridine orange and ethidium bromide showed that heptelidic acid inhibited apoptosis. Furthermore, it was found that DNA fragmentation and caspase-3 activation, the biological hallmarks of apoptosis, were inhibited by the compound in a dose-dependent manner, suggesting that heptelidic acid inhibits etoposide-induced apoptosis via downregulation of caspases. PMID:19734716

Kim, Jin Hee; Lee, Choong Hwan

2009-08-01

262

Inhibition of heme crystal growth by antimalarials and other compounds: implications for drug discovery  

Microsoft Academic Search

During intraerythrocytic infection, Plasmodium falciparum parasites crystallize toxic heme released during hemoglobin catabolism. The proposed mechanism of quinoline inhibition of crystal growth is either by a surface binding or a substrate sequestration mechanism. The kinetics of heme crystal growth was examined in this work using a new high-throughput crystal growth determination assay based on the differential solubility of free vs.

Curtis Robert Chong; David Joseph Sullivan

2003-01-01

263

Phytotoxicity of coloured substances: is Lemna Duckweed an alternative to the algal growth inhibition test?  

Microsoft Academic Search

Coloured substances cause problems when interpreting algal tests, because effects due to light absorption can interact with potential toxicity. The Lemna Duckweed growth inhibition test can complement the algal test, on condition that the test is performed on a black, not reflecting surface. On white surfaces, test solution colour can strongly impact Lemna growth. For example, average control sample growth

Michael Cleuvers; Hans-Toni Ratte

2002-01-01

264

Growth hormone receptor inhibition decreases the growth and metastasis of pancreatic ductal adenocarcinoma  

PubMed Central

Pancreatic cancer is the only major cancer with very low survival rates (1%). It is the fourth leading cause of cancer-related death. Hyperactivated growth hormone receptor (GHR) levels have been shown to increase the risk of cancer in general and this pathway is a master regulator of key cellular functions like proliferation, apoptosis, differentiation, metastasis, etc. However, to date there is no available data on how GHR promotes pancreatic cancer pathogenesis. Here, we used an RNA interference approach targeted to GHR to determine whether targeting GHR is an effective method for controlling pancreatic cancer growth and metastasis. For this, we used an in vitro model system consisting of HPAC and PANC-1 pancreatic cancer cells lines. GHR is upregulated in both of these cell lines and silencing GHR significantly reduced cell proliferation and viability. Inhibition of GHR also reduced the metastatic potential of pancreatic cancer cells, which was aided through decreased colony-forming ability and reduced invasiveness. Flow cytometric and western blot analyses revealed the induction of apoptosis in GHR silenced cells. GHR silencing affected phosphatidylinositol 3 kinase/AKT, mitogen extracellular signal-regulated kinase/extracellular signal-regulated kinase, Janus kinase/signal transducers and activators of transcription and mammalian target of rapamycin signaling, as well as, epithelial to mesenchymal transition. Interestingly, silencing GHR also suppressed the expression of insulin receptor-? and cyclo-oxygenease-2. Altogether, GHR silencing controls the growth and metastasis of pancreatic cancer and reveals its importance in pancreatic cancer pathogenesis. PMID:25301264

Subramani, Ramadevi; Lopez-Valdez, Rebecca; Salcido, Alyssa; Boopalan, Thiyagarajan; Arumugam, Arunkumar; Nandy, Sushmita; Lakshmanaswamy, Rajkumar

2014-01-01

265

Molecular interaction of pinic acid with sulfuric acid: exploring the thermodynamic landscape of cluster growth.  

PubMed

We investigate the molecular interactions between the semivolatile ?-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated from the corresponding ?G values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ?G values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid cluster. The involvement of more than one pinic acid molecule in a single cluster is observed to lead to the formation of favorable (pinic acid)2(H2SO4) and (pinic acid)2(H2SO4)2 clusters. The identified most favorable growth paths starting from a single pinic acid molecule lead to closed structures without the further possibility for attachment of either sulfuric acid or pinic acid. This suggests that pinic acid cannot be a key species in the first steps in nucleation, but the favorable interactions between sulfuric acid and pinic acid imply that pinic acid can contribute to the subsequent growth of an existing nucleus by condensation. PMID:24988284

Elm, Jonas; Kurtén, Theo; Bilde, Merete; Mikkelsen, Kurt V

2014-09-11

266

Inhibition of pathological retinal angiogenesis by the integrin ?v?3 antagonist tetraiodothyroacetic acid (tetrac)  

PubMed Central

Retinal angiogenesis is a major cause of blindness in ischemic retinopathies including diabetic retinopathy and retinopathy of prematurity. Integrin ?v?3 is a promising therapeutic target for ocular angiogenesis, modulating the pro-angiogenic actions of multiple growth factors. In this study, we sought to determine the effects of the integrin ?v?3 antagonist tetra-iodothyroacetic acid (tetrac) on the angiogenic actions of VEGF and erythropoietin (EPO) in cultured human retinal endothelial cells. In addition, we investigated the effect of tetrac and a nanoparticulate formulation of tetrac on retinal angiogenesis in vivo, in the mouse oxygen-induced retinopathy (OIR) model. Tetrac inhibitory activity was evaluated in human retinal endothelial cells treated with VEGF and/or EPO. Endothelial cell proliferation, migration, and tube formation were assessed, in addition to phosphorylation of ERK1/2. For the studies of the oxygen-induced retinopathy model, C57BL/6 mice were exposed to 75% oxygen from postnatal day (P)7 to P12, and then returned to room air. Tetrac and tetrac-nanoparticle (tetrac-NP) were administered at P12 and P15 by either intraperitoneal or intravitreal injection. Retinal neovascularization was quantitated at P18. Tetrac significantly inhibited pro-angiogenic effects of VEGF and/or EPO on retinal endothelial cells, indicating that the angiogenic effects of both growth factors are dependent on integrin ?v?3. Retinal neovascularization in the OIR model was significantly inhibited by both tetrac and tetrac-NP. These results indicate that the integrin ?v?3 antagonist, tetrac, is an effective inhibitor of retinal angiogenesis. The ability of tetrac to inhibit the pro-angiogenic effect of both VEGF and EPO on retinal endothelial cells suggests that tetrac (and antagonism of integrin ?v?3) is a viable therapeutic strategy for proliferative diabetic retinopathy. PMID:22123068

Yoshida, Takeshi; Gong, Junsong; Xu, Zhenhua; Wei, Yanhong; Duh, Elia J.

2011-01-01

267

Inhibition of growth and alteration of host cell interactions of Pasteurella multocida with natural byproducts.  

PubMed

Pasteurella multocida is a leading cause of fowl cholera in both free-range pasture and conventional/commercially raised poultry. Its infection is a serious threat to poultry health and overall flock viability. Organic poultry is comparatively more vulnerable to this pathogen. It is a significant cause of production loss and price increase of poultry products, specifically organic poultry products. Some plant products are well documented as sources of natural antimicrobials such as polyphenols found in different berry pomaces and citrus oil. Pomace, a byproduct (primarily of seeds and skins) of fruits used for juice and wine production, and citrus oil, the byproduct of citrus juice production, show promising antimicrobial activity against various pathogens. Here, we showed for the first time that blackberry and blueberry pomace extracts and citrus oil inhibited P. multocida growth. Minimum bactericidal concentrations were determined as 0.3 and 0.4 mg/mL gallic acid equivalent for blackberry and blueberry pomace extracts, respectively. Similarly, only 0.05% citrus oil (vol/vol) completely inhibited P. multocida growth. Under shaking conditions, the antimicrobial activity of both pomace extracts and citrus oil was more intensive. Even citrus oil vapor also significantly reduced the growth of P. multocida. In addition, cell surface hydrophobicity of P. multocida was increased by 2- to 3-fold and its adherence to chicken fibroblast (DF1) and bovine mammary gland (MacT) cells was reduced significantly in the presence of pomace extracts only. This study indicates that these natural products might be good alternatives to conventional antimicrobial agents, and hence, may be used as feed or water supplements to control fowl cholera and reduce production loss caused by P. multocida. PMID:24879687

Salaheen, S; Almario, J A; Biswas, D

2014-06-01

268

Ursodeoxycholic acid (UDCA) can inhibit deoxycholic acid (DCA)-induced apoptosis via modulation of EGFR/Raf-1/ERK signaling in human colon cancer cells.  

PubMed

Ursodeoxycholic acid (UDCA), a hydrophilic bile acid, is known as a cytoprotective agent. UDCA prevents apoptosis induced by a variety of stress stimuli including cytotoxic bile acids such as deoxycholic acid (DCA). Here we examined the molecular mechanism by which UDCA can antagonize DCA-induced apoptosis in human colon cancer cells. UDCA pretreatment decreases the number of apoptotic cells caused by exposure to DCA and UDCA. Further studies of the signaling pathway showed that UDCA pretreatment suppressed DNA binding activity of activator protein-1 and this was accompanied by downregulation of both extracellular signal-regulated kinase (ERK) and Raf-1 kinase activities stimulated by exposure to DCA. DCA was also found to activate epidermal growth factor receptor (EGFR) activity and UDCA inhibited this. Collectively, these findings suggest that the inhibitory effect of UDCA in DCA-induced apoptosis is partly mediated by modulation of EGFR/Raf-1/ERK signaling. PMID:14747693

Im, Eunok; Martinez, Jesse D

2004-02-01

269

Mullerian Inhibiting Substance inhibits cervical cancer cell growth via a pathway involving p130 and p107.  

PubMed

In addition to causing regression of the Mullerian duct in the male embryo, Mullerian Inhibiting Substance (MIS) inhibits the growth of epithelial ovarian cancer cells, which are known to be of Mullerian origin. Because the uterine cervix is derived from the same Mullerian duct precursor as the epithelium of the ovary, we tested the hypothesis that cervical cancer cells might also respond to MIS. A number of cervical cancer cell lines express the MIS type II receptor, and MIS inhibits the growth of both human papilloma virus-transformed and non-human papilloma virus-transformed cervical cell lines, with a more dramatic effect seen in the latter. As in the ovarian cancer cell line OVCAR8, suppression of growth of the C33A cervical cancer cell line by MIS is associated with induction of the p16 tumor suppressor protein. However, in contrast to OVCAR8 cells, induction of p130 and p107 appears to play an important role in the inhibition of growth of C33A cells by MIS. Finally, normal cervical tissue expresses the MIS type II receptor in vivo, supporting the idea that MIS could be a targeted therapy for cervical cancer. PMID:14671316

Barbie, Thanh U; Barbie, David A; MacLaughlin, David T; Maheswaran, Shyamala; Donahoe, Patricia K

2003-12-23

270

Mullerian Inhibiting Substance inhibits cervical cancer cell growth via a pathway involving p130 and p107  

PubMed Central

In addition to causing regression of the Mullerian duct in the male embryo, Mullerian Inhibiting Substance (MIS) inhibits the growth of epithelial ovarian cancer cells, which are known to be of Mullerian origin. Because the uterine cervix is derived from the same Mullerian duct precursor as the epithelium of the ovary, we tested the hypothesis that cervical cancer cells might also respond to MIS. A number of cervical cancer cell lines express the MIS type II receptor, and MIS inhibits the growth of both human papilloma virus-transformed and non-human papilloma virus-transformed cervical cell lines, with a more dramatic effect seen in the latter. As in the ovarian cancer cell line OVCAR8, suppression of growth of the C33A cervical cancer cell line by MIS is associated with induction of the p16 tumor suppressor protein. However, in contrast to OVCAR8 cells, induction of p130 and p107 appears to play an important role in the inhibition of growth of C33A cells by MIS. Finally, normal cervical tissue expresses the MIS type II receptor in vivo, supporting the idea that MIS could be a targeted therapy for cervical cancer. PMID:14671316

Barbie, Thanh U.; Barbie, David A.; MacLaughlin, David T.; Maheswaran, Shyamala; Donahoe, Patricia K.

2003-01-01

271

Inhibition of Activity of Catalase from Potato Tubers by Salicylic and Succinic Acids  

Microsoft Academic Search

It was found that salicylic acid inhibits the activity of catalase from potato tubers in vitro. Succinic acid suppressed catalase activity at the same concentrations that salicylate; however, its effect was more long-term. Bovine catalase was less sensitive to salicylic and succinic acids than potato catalase. In the past years, the attention of researchers has been attracted to studying the

Ya. S. Panina; N. I. Vasyukova; O. L. Ozeretskovskaya

2004-01-01

272

Eco friendly inhibitor for corrosion inhibition of mild steel in phosphoric acid medium  

Microsoft Academic Search

The inhibition effect of Zenthoxylum alatum plant extract on the corrosion of mild steel in 20, 50 and 88% aqueous orthophosphoric acid has been investigated by weight loss and electrochemical impedance spectroscopy (EIS). Plant extract is able to reduce the corrosion of steel more effectively in 88% phosphoric acid than in 20% phosphoric acid. The effect of temperature on the

G Gunasekaran; L. R Chauhan

2004-01-01

273

Ginkgolic acid inhibits protein SUMOylation by blocking formation of the E1-SUMO intermediate.  

PubMed

Protein modification by small ubiquitin-related modifier proteins (SUMOs) controls diverse cellular functions. Dysregulation of SUMOylation or deSUMOylation processes has been implicated in the development of cancer and neurodegenerative diseases. However, no small-molecule inhibiting protein SUMOylation has been reported so far. Here, we report inhibition of SUMOylation by ginkgolic acid and its analog, anacardic acid. Ginkgolic acid and anacardic acid inhibit protein SUMOylation both in vitro and in vivo without affecting in vivo ubiquitination. Binding assays with a fluorescently labeled probe showed that ginkgolic acid directly binds E1 and inhibits the formation of the E1-SUMO intermediate. These studies will provide not only a useful tool for investigating the roles of SUMO conjugations in a variety of pathways in cells, but also a basis for the development of drugs targeted against diseases involving aberrant SUMOylation. PMID:19246003

Fukuda, Isao; Ito, Akihiro; Hirai, Go; Nishimura, Shinichi; Kawasaki, Hisashi; Saitoh, Hisato; Kimura, Ken-Ichi; Sodeoka, Mikiko; Yoshida, Minoru

2009-02-27

274

Effects of different sterols on the inhibition of cell culture growth caused by the growth retardant tetcyclacis  

Microsoft Academic Search

Cell division in cell suspension cultures can be completely blocked by the growth retardant tetcyclacis at a concentration of 10-4 mol l-1. In rice cells it has been demonstrated that the growth inhibition can be completely overcome by application of cholesterol independent of the duration of pretreatment with tetcyclacis. In suspension cultures of maize and soybean, too, the effect of

K. Grossmann; E. W. Weiler; J. Jung

1985-01-01

275

Sirolimus inhibits growth of human hepatoma cells alone or combined with tacrolimus, while tacrolimus promotes cell growth  

Microsoft Academic Search

Abstract Abstract Abstract Abstract AIM: Standard immunosuppression after organ transplan- tation stimulates tumor growth. Sirolimus has a strong antiproliferative and a tumor inhibiting effect. The purpose is to assess the effect on tumor growth of the immuno- suppressive compounds sirolimus and tacrolimus alone and in combination on cells of human hepatocellular carcinoma. METHODS: We used the human cell lines SK-Hep

Guido Schumacher; Marijke Oidtmann; Anne Rueggeberg; Dietmar Jacob; Sven Jonas; Jan M. Langrehr; Ruth Neuhaus; Marcus Bahra; Peter Neuhaus; Langrehr JM; Neuhaus P. Sirolimus

276

Fatty acid regulates gene expression and growth of human prostate cancer PC-3 cells  

NASA Technical Reports Server (NTRS)

It has been proposed that the omega-6 fatty acids increase the rate of tumor growth. Here we test that hypothesis in the PC-3 human prostate tumor. We found that the essential fatty acids, linoleic acid (LA) and arachidonic acid (AA), and the AA metabolite PGE(2) stimulate tumor growth while oleic acid (OA) and the omega-3 fatty acid, eicosapentaenoic acid (EPA) inhibited growth. In examining the role of AA in growth response, we extended our studies to analyze changes in early gene expression induced by AA. We demonstrate that c-fos expression is increased within minutes of addition in a dose-dependent manner. Moreover, the immediate early gene cox-2 is also increased in the presence of AA in a dose-dependent manner, while the constitutive cox-1 message was not increased. Three hours after exposure to AA, the synthesis of PGE(2) via COX-2 was also increased. Previous studies have demonstrated that AA was primarily delivered by low density lipoprotein (LDL) via its receptor (LDLr). Since it is known that hepatomas, acute myelogenous leukemia and colorectal tumors lack normal cholesterol feedback, we examined the role of the LDLr in growth regulation of the PC-3 prostate cancer cells. Analysis of ldlr mRNA expression and LDLr function demonstrated that human PC-3 prostate cancer cells lack normal feedback regulation. While exogenous LDL caused a significant stimulation of cell growth and PGE(2) synthesis, no change was seen in regulation of the LDLr by LDL. Taken together, these data show that normal cholesterol feedback of ldlr message and protein is lost in prostate cancer. These data suggest that unregulated over-expression of LDLr in tumor cells would permit increased availability of AA, which induces immediate early genes c-fos and cox-2 within minutes of uptake.

Hughes-Fulford, M.; Chen, Y.; Tjandrawinata, R. R.

2001-01-01

277

Gellan sulfate inhibits Plasmodium falciparum growth and invasion of red blood cells in vitro  

PubMed Central

Here, we assessed the sulfated derivative of the microbial polysaccharide gellan gum and derivatives of ? and ?-carrageenans for their ability to inhibit Plasmodium falciparum 3D7 and Dd2 growth and invasion of red blood cells in vitro. Growth inhibition was assessed by means of flow cytometry after a 96-h exposure to the inhibitors and invasion inhibition was assessed by counting ring parasites after a 20-h exposure to them. Gellan sulfate strongly inhibited invasion and modestly inhibited growth for both P. falciparum 3D7 and Dd2; both inhibitory effects exceeded those achieved with native gellan gum. The hydrolyzed ?-carrageenan and oversulfated ?-carrageenan were less inhibitory than their native forms. In vitro cytotoxicity and anticoagulation assays performed to determine the suitability of the modified polysaccharides for in vivo studies showed that our synthesized gellan sulfate had low cytotoxicity and anticoagulant activity. PMID:24740150

Recuenco, Frances Cagayat; Kobayashi, Kyousuke; Ishiwa, Akiko; Enomoto-Rogers, Yukiko; Fundador, Noreen Grace V.; Sugi, Tatsuki; Takemae, Hitoshi; Iwanaga, Tatsuya; Murakoshi, Fumi; Gong, Haiyan; Inomata, Atsuko; Horimoto, Taisuke; Iwata, Tadahisa; Kato, Kentaro

2014-01-01

278

Influence of some growth regulators and cations on inhibition of chlorophyll biosynthesis by lead in maize  

SciTech Connect

Phytotoxic effects of Pb pollution are well established. In order to analyse the physiological basis of toxic symptoms and of reduced plant productivity, its effect on chlorophyll content has been examined in some plants. Thus, a decrease in total chlorophyll content during Pb supply has been observed in oats, mung beam, pea, etc. The activity of delta aminolevulinic acid dehydratase, an important enzyme in the biosynthesis of heme pigments, is inhibited by Pb in mung bean and several other species. This observation may perhaps indicate that a reduction in chlorophyll content in the presence of lead is due to an inhibition of pigment synthesis. The effect of Pb on greening maize leaf segments in the presence of various precursors of chlorophyll has been studied in the present investigation to evaluate this hypothesis. The effect of some growth regulators and cations, which could otherwise modify chlorophyll biosynthesis, has been examined to see whether the toxic effects of Pb on photosynthetic pigments could also be modified by these effectors. 16 refs., 4 tabs.

Sinha, S.K. (Council of Science Technology, Lucknow (India)); Srivastava, H.S. (Rohilkhand Univ., Bareilly (India)); Tripathi, R.D. (National Botanical Research Institute, Lucknow (India))

1993-08-01

279

Acidic deposition, nutrient leaching and forest growth  

Microsoft Academic Search

Studies in Germany and confirmed in North America established that the forest decline that developed in the late 1970's and 80's resulted from a deficiency in one or more of the nutrient cations: Ca2+, Mg2+, and K+. These nutrients are essential to the structure of the foliage, to photosynthesis and to the growth of the trees. The reactions and mechanisms

George H. Tomlinson

2003-01-01

280

Somatostatin Analogues Inhibit Growth of Pancreatic Cancer by Stimulating Tyrosine Phosphatase  

Microsoft Academic Search

Several analogues of somatostatin were examined in the Mia PaCa-2 human pancreatic cancer cell line for their ability to promote tyrosine phosphatase activity affecting the receptors for the epidermal growth factor. The inhibition of growth of the Mia PaCa-2 cells in culture was also evaluated to determine the mechanism of action of somatostatin analogues and their relative effectiveness in inhibiting

C. Liebow; C. Reilly; M. Serrano; A. V. Schally

1989-01-01

281

Inhibition of cell growth by bafilomycin A 1 , a selective inhibitor of vacuolar H + ATPase  

Microsoft Academic Search

Summary  Bafilomycin A1, a potent selective inhibitor of vacuolar H+-ATPase, inhibited the growth of a variety of cultured cells dose-dependently, including golden hamster embryo and NIH-3T3\\u000a fibroblasts, whether or not they were transformed, and PC12 and HeLa cells. The concentration of bafilomycin A1 for 50% inhibition of cell growth ranged from 10 to 50 nM. The dose response was nearly parallel

Shoji Ohkuma; Sakae Shimizu; Masahiko Noto; Yoshimichi Sai; Kuninori Kinoshita; Hiro-Omi Tamura

1993-01-01

282

Growth inhibition by exogenous proline and its metabolism in saltgrass ( Distichlis spicata ) suspension cultures  

Microsoft Academic Search

The growth of Distichlis spicata suspension cultures in LS medium without NaCl was inhibited 54% by 2 mM proline. In medium containing 260 mM NaCl, 10 mM proline inhibited growth by only 22%. The uptake and metabolism of 10 mM L-[1-13C] proline was followed by 13C NMR and ninhydrin analyses of suspensions cultured in the presence of 0 or 260

Manuel M. Rodriguez; James W. Heyser

1988-01-01

283

Inhibition of endometrial cancer by n-3 polyunsaturated fatty acids in preclinical models.  

PubMed

Although preclinical and epidemiologic studies have shown the importance of n-3 polyunsaturated fatty acids (PUFA) in the prevention of hormone-responsive cancers such as breast cancer, evidence of the association between n-3 PUFAs and endometrial cancer risk is limited and no previous study has examined the effect of n-3 PUFAs on endometrial cancer in cellular and animal models. In this study, we demonstrated that docosahexenoic acid (DHA) dose- and time-dependently inhibited endometrial cancer cell proliferation, colony formation, and migration and promoted apoptosis. Dietary n-3 PUFAs efficiently prevented endometrial cancer cell growth in xenograft models. Moreover, ectopic expression of fat-1, a desaturase, catalyzed the conversion of n-6 to n-3 PUFAs and produced n-3 PUFAs endogenously, also suppressed endometrial tumor cell growth and migration, and potentiated apoptosis in endometrial cancer cell lines. Interestingly, implanted endometrial cancer cells were unable to grow in fat-1 transgenic SCID mice. Further study revealed that mTOR signaling, which plays an essential role in cell proliferation and endometrial tumorigenesis, is a target of n-3 PUFAs. Exogenous or endogenous n-3 PUFAs efficiently suppressed both mTOR complex 1 (mTORC1) and mTORC2 in vitro and in vivo. Moreover, both dietary n-3 PUFAs and transgenic expression of fat-1 in mice effectively repressed mTORC1/2 signaling and endometrial growth elicited by unopposed estrogen. Taken together, our findings provide comprehensive preclinical evidences that n-3 PUFAs efficiently prevent endometrial cancer and establish mTORC1/2 as a target of n-3 PUFAs. PMID:24866178

Zheng, Hang; Tang, Hongjun; Liu, Miao; He, Minhong; Lai, Pinglin; Dong, Heling; Lin, Jun; Jia, Chunhong; Zhong, Mei; Dai, Yifan; Bai, Xiaochun; Wang, Liping

2014-08-01

284

Inhibition by ascorbic acid of NMDA-evoked acetylcholine release in rabbit caudate nucleus  

Microsoft Academic Search

The interaction of ascorbic acid and of dehydroascorbic acid with acetylcholine (ACh) release in rabbit caudate nucleus was investigated. The presence of ascorbic acid in the superfusion medium decreased the release of ACh evoked by N-methyl-d-aspartate (NMDA), but not by electrical stimulation. The pH of the buffer was always maintained at 7.4. Inhibition occurred even at 570 µmol\\/l ascorbic acid,

Thomas J. Feuerstein; Giinter Weinheimer; Giinter Lang; Thomas Ginap; Reinhard Roßner

1993-01-01

285

Inhibition of gonadotropin-stimulated ovarian steroid production by polyunsaturated fatty acids in teleost fish  

Microsoft Academic Search

The effects of the polyynsaturated fatty acids (PUFAs)—eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic\\u000a acid (AA)—onin vitro steroid production by full-grown prematurational ovarian follicles from goldfish and rainbow trout were investigated. EPA\\u000a and DHA inhibited gonadotropin-stimulated testosterone production in a dose-related manner, but AA was inhibitory only at\\u000a the highest dose tested (400 ?M). AA alone stimulated testosterone production

François Mercure; Glen Van Der Kraak

1995-01-01

286

Alpha lipoic acid selectively inhibits proliferation and adhesion to fibronectin of v-H-ras-transformed 3Y1 cells.  

PubMed

Here, we focused on the effects of racemic ?-lipoic acid on proliferation and adhesion properties of 3Y1 rat fibroblasts and the v-H-ras-transformed derivative, HR-3Y1-2 cells. Racemic ?-lipoic acid inhibited proliferation of HR-3Y1-2 but not 3Y1 cells at 0.3 and 1.0 mM. R-(+)-?-lipoic acid also inhibited proliferation of HR-3Y1-2 cells equivalent to that of racemic ?-lipoic acid. In addition, racemic ?-lipoic acid decreased intracellular reactive oxygen species levels in HR-3Y1 cells but not 3Y1 cells. Next, we evaluated the effects of racemic ?-lipoic acid on cell adhesion to fibronectin. The results indicated that racemic ?-lipoic acid decreased adhesive ability of HR-3Y1-2 cells to fibronectin-coated plates. As blocking antibody experiment revealed that ?1-integrin plays a key role in cell adhesion in this experimental system, the effects of racemic ?-lipoic acid on the expression of ?1-integrin were examined. The results indicated that racemic ?-lipoic acid selectively downregulated the expression of cell surface ?1-integrin expression in HR-3Y1-2 cells. Intriguingly, exogenous hydrogen peroxide upregulated cell surface ?1-integrin expression in 3Y1 cells. Taken together, these data suggest that reduction of intracellular reactive oxygen species levels by ?-lipoic acid could be an effective means of ameliorating abnormal growth and adhesive properties in v-H-ras transformed cells. PMID:22573927

Yamasaki, Masao; Iwase, Masahiro; Kawano, Kazuo; Sakakibara, Yoichi; Suiko, Masahito; Nishiyama, Kazuo

2012-05-01

287

Growth hormone receptor inhibition decreases the growth and metastasis of pancreatic ductal adenocarcinoma.  

PubMed

Pancreatic cancer is the only major cancer with very low survival rates (1%). It is the fourth leading cause of cancer-related death. Hyperactivated growth hormone receptor (GHR) levels have been shown to increase the risk of cancer in general and this pathway is a master regulator of key cellular functions like proliferation, apoptosis, differentiation, metastasis, etc. However, to date there is no available data on how GHR promotes pancreatic cancer pathogenesis. Here, we used an RNA interference approach targeted to GHR to determine whether targeting GHR is an effective method for controlling pancreatic cancer growth and metastasis. For this, we used an in vitro model system consisting of HPAC and PANC-1 pancreatic cancer cells lines. GHR is upregulated in both of these cell lines and silencing GHR significantly reduced cell proliferation and viability. Inhibition of GHR also reduced the metastatic potential of pancreatic cancer cells, which was aided through decreased colony-forming ability and reduced invasiveness. Flow cytometric and western blot analyses revealed the induction of apoptosis in GHR silenced cells. GHR silencing affected phosphatidylinositol 3 kinase/AKT, mitogen extracellular signal-regulated kinase/extracellular signal-regulated kinase, Janus kinase/signal transducers and activators of transcription and mammalian target of rapamycin signaling, as well as, epithelial to mesenchymal transition. Interestingly, silencing GHR also suppressed the expression of insulin receptor-? and cyclo-oxygenease-2. Altogether, GHR silencing controls the growth and metastasis of pancreatic cancer and reveals its importance in pancreatic cancer pathogenesis.Experimental & Molecular Medicine (2014) 46, e117; doi:10.1038/emm.2014.61; published online 10 October 2014. PMID:25301264

Subramani, Ramadevi; Lopez-Valdez, Rebecca; Salcido, Alyssa; Boopalan, Thiyagarajan; Arumugam, Arunkumar; Nandy, Sushmita; Lakshmanaswamy, Rajkumar

2014-01-01

288

Inhibition of Mycobacterial Growth In Vitro following Primary but Not Secondary Vaccination with Mycobacterium bovis BCG  

PubMed Central

Despite the widespread use of the Mycobacterium bovis BCG vaccine, there are more than 9 million new cases of tuberculosis (TB) every year, and there is an urgent need for better TB vaccines. TB vaccine candidates are selected for evaluation based in part on the detection of an antigen-specific gamma interferon (IFN-?) response. The measurement of mycobacterial growth in blood specimens obtained from subjects immunized with investigational TB vaccines may be a better in vitro correlate of in vivo vaccine efficacy. We performed a clinical study with 30 United Kingdom adults who were followed for 6 months to evaluate the abilities of both a whole-blood- and a novel peripheral blood mononuclear cell (PBMC)-based mycobacterial growth inhibition assay to measure a response to primary vaccination and revaccination with BCG. Using cryopreserved PBMCs, we observed a significant improvement in mycobacterial growth inhibition following primary vaccination but no improvement in growth inhibition following revaccination with BCG (P < 0.05). Mycobacterial growth inhibition following primary BCG vaccination was not correlated with purified protein derivative (PPD) antigen-specific IFN-? enzyme-linked immunospot (ELISPOT) responses. We demonstrate that a mycobacterial growth inhibition assay can detect improved capacity to control growth following primary immunization, but not revaccination, with BCG. This is the first study to demonstrate that an in vitro growth inhibition assay can identify a difference in vaccine responses by comparing both primary and secondary BCG vaccinations, suggesting that in vitro growth inhibition assays may serve as better surrogates of clinical efficacy than the assays currently used for the assessment of candidate TB vaccines. PMID:23986316

Fletcher, Helen A.; Tanner, Rachel; Wallis, Robert S.; Meyer, Joel; Manjaly, Zita-Rose; Harris, Stephanie; Satti, Iman; Silver, Richard F.; Hoft, Dan; Kampmann, Beate; Walker, K. Barry; Dockrell, Hazel M.; Fruth, Uli; Barker, Lew; McShane, Helen

2013-01-01

289

Inhibition of complement by covalent attachment of rosmarinic acid to activated C3b  

Microsoft Academic Search

Rosmarinic acid has been reported to inhibit complement activation in vivo as well as in vitro. Previous studies suggested that the inhibitory effect was due to inhibition of C3\\/C5 convertases, but inhibition of C3b attachment would yield the same results. Recent work in our laboratory demonstrated that compounds with polyhydroxylated phenyl rings are highly reactive with the thioester bond in

Arvind Sahu; Nenoo Rawal; Michael K. Pangburn

1999-01-01

290

Inhibiting properties and adsorption of some thioamides on mild steel in sulphuric acid solutions  

Microsoft Academic Search

The inhibiting properties and adsorption behaviour of thioacetamide (TAA), thiobenzamide (TBA) and thiocinnamamide (TCA) on\\u000a mild steel in sulphuric acid solution were studied by gravimetric, potentiodynamic polarization and electrochemical impedance\\u000a spectroscopy (EIS) measurements. TBA and TCA were found to be mixed type inhibitors providing good corrosion inhibition. Different\\u000a mechanisms of adsorption and corrosion inhibition were observed for the tested thioamides.

E. Lazarova; G. Petkova; T. Iankova; L. Ivan; G. Neikov

2008-01-01

291

Retinoic acid induces transforming growth factor-beta 2 in cultured keratinocytes and mouse epidermis.  

PubMed Central

We have studied the functional interaction between retinoic acid and transforming growth factor-beta (TGF-beta), using the mouse epidermis as a model system. Treatment with retinoic acid increases expression of TGF-beta 2 in cultured keratinocytes in vitro, as well as in the epidermis in vivo. This TGF-beta 2 is secreted in a biologically active form that can bind to surface receptors, in contrast to most other conditions in which TGF-beta is secreted in a latent form. Specific antibodies to TGF-beta 2 partially reverse the ability of retinoic acid to inhibit DNA synthesis in cultured keratinocytes. The regulation of TGF-beta 2 expression by retinoic acid may have important physiological and pharmacological roles in the maintenance of epidermal homeostasis. Images PMID:2519621

Glick, A B; Flanders, K C; Danielpour, D; Yuspa, S H; Sporn, M B

1989-01-01

292

Inhibition of the catecholase activity of biomimetic dinuclear copper complexes by kojic acid  

Microsoft Academic Search

The inhibition of the catechol oxidase activity exhibited by three dinuclear copper(II) complexes, derived from different\\u000a diaminotetrabenzimidazole ligands, by kojic acid [5-hydroxy-2-(hydroxymethyl)-?-pyrone] has been studied. The catalytic mechanism of the catecholase reaction proceeds in two steps and for both of these\\u000a inhibition by kojic acid is of competitive type. The inhibitor binds strongly to the dicopper(II) complex in the first

G. Battaini; E. Monzani; L. Casella; L. Santagostini; R. Pagliarin

2000-01-01

293

Inhibition of carbon steel corrosion by azathione derivatives in organic acid solutions  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the inhibitive effect of azathiones, namely cyclopentyl-tetrahydro-azathione, cyclohexyl-tetrahydro-azathione and isobutyl-methyl-tetrahydro-azathione on the corrosion of carbon steel in formic and acetic acid solution. The effect of inhibitor concentration, immersion time, acid concentration, and solution temperature on the inhibition efficiencies of the selected azathiones were studied systematically. Design\\/methodology\\/approach – The synthesis of

Sadaf Khan; M. Z. A. Rafiquee; Nidhi Saxena; M. A. Quraishi

2009-01-01

294

Hypergravity inhibits elongation growth of azuki bean epicotyls independently of the direction of stimuli  

NASA Astrophysics Data System (ADS)

We examined the effects of basipetal, horizontal, and acropetal hypergravity stimulation on growth and cell wall properties of azuki bean seedlings. Horizontal and acropetal hypergravity inhibited elongation growth of epicotyls by decreasing the cell wall extensibility, as did basipetal hypergravity. Hypergravity stimulation increased the thickness of cell walls and suppressed xyloglucan breakdown regardless of direction. All hypergravity treatments increased the pH in the apoplastic fluid, which is involved in the processes of the suppression of xyloglucan breakdown. Gadolinium and lanthanum, both blockers of mechanoreceptors, nullified the growth-inhibiting effects of hypergravity. These results show that growth inhibition by hypergravity is independent of its direction in azuki bean epicotyls. The findings also suggest that mechanoreceptors on the plasma membrane perceive the gravity signal independently of its direction, and affect growth of azuki bean epicotyls.

Soga, K.; Wakabayashi, K.; Kamisaka, S.; Hoson, T.

295

Efficient inhibition of intraperitoneal human ovarian cancer growth by short hairpin RNA targeting CD44.  

PubMed

CD44 is one member of a big glycoprotein family involved in adhesion of cells or cells and extracellular matrix (ECM). The heavily glycosylated CD44 has been proved to be a major receptor of hyaluronan and a marker of stem cells in ovarian cancer. Here, using short hairpin (shRNA) against CD44, we demonstrate that knockdown CD44 could inhibit cancer growth efficiently compared with controls. Plasmid targeting CD44 gene (pshCD44) or non-relative control sequences (pshHK) was constructed and delivered to ovarian cancer by biodegradable poly D, L-Lactide-co-glycolide acid nanoparticles (PLGANPs). Nude mice were utilized in an intraperitoneal model of ovarian carcinomatosis to assess antitumor efficacy in vivo. Antitumor efficacy was estimated by changes in tumor weights, proliferation (Ki-67), apoptosis (TUNEL) and angiogenesis (CD31 staining and alginate-encapsulated tumor beads assay) in tumor cells. As results, pshCD44 or pshHK could be effectively transfected into SKOV-3 cells by PLGANPs. Tumor weight in pshCD44/PLGANPs group was suppressed by 45% and 50% compared with those in pshHK/PLGANPs and untreated group, respectively (Ps < 0.001). Inhibition of cell proliferation, induction of apoptosis and reduction of angiogenesis in tumor cells of pshCD44/PLGANPs group also show significant difference compared with those in control groups (Ps < 0.05), respectively. These results indicate that pshCD44 delivered by PLGANPs might be a potential approach in ovarian cancer therapy, and point towards a mechanism involving the inhibition of angiogenesis, cellular proliferation and the induction of apoptosis. PMID:24824928

Zou, L; Yi, T; Song, X; Li, S; Wei, Y; Zhao, X

2014-01-01

296

Epidermal growth factor receptor inhibition strategies in oncology  

Microsoft Academic Search

Molecular targeting strategies for cancer therapy are distinct from conventional chemotherapy and radiotherapy in their potential to provide increased tumor specificity. One particular molecular target of high promise in oncology is the epidermal growth factor receptor (EGFR). The EGFR is overexpressed, dysregulated or mutated in many epithelial malignancies, and EGFR activation appears important in tumor growth and progression. Advances in

P M Harari

2004-01-01

297

Inhibition of polyketide synthesis in Alternaria alternata by the fatty acid synthesis inhibitor cerulenin.  

PubMed Central

The fatty acid synthase inhibitor cerulenin (50 to 100 micrograms/ml) inhibited production of the polyketide mycotoxins alternariol (AOH) and alternariol monomethyl ether (AME) by the mold Alternaria alternata. The results suggested that AOH synthesis was inhibited by a direct mechanism by cerulenin, whereas production of AME was probably limited by a shortage of the precursor AOH. PMID:1575478

Hiltunen, M; Soderhall, K

1992-01-01

298

Inhibition of corrosion of mild steel in sulphuric acid medium by Calotropis procera  

Microsoft Academic Search

Purpose – The purpose of this paper is to evaluate the corrosion inhibition potential of Calotropis procera in sulphuric acid medium on mild steel with a view to developing green corrosion inhibitors. Design\\/methodology\\/approach – Extract of the C. procera was studied for its corrosion inhibitive effect by weight loss, electrochemical, SEM and UV methods. Using weight loss measurement data, mechanism

P. B. Raja; M. G. Sethuraman

2009-01-01

299

Phytochrome-mediated growth inhibition of seminal roots in rice seedlings.  

PubMed

In rice (Oryza sativa) seedlings, continuous white-light irradiation inhibited the growth of seminal roots but promoted the growth of crown roots. In this study, we examined the mechanisms of photoinhibition of seminal root growth. Photoinhibition occurred in the absence of nitrogen but increased with increasing nitrogen concentrations. In the presence of nitrogen, photoinhibition was correlated with coiling of the root tips. The seminal roots were most photosensitive 48-72 h after germination during the 7-day period after germination. White-light irradiation for at least 6 h was required for photoinhibition, and the Bunsen-Roscoe law of reciprocity was not observed. Experiments with phytochrome mutants showed that far-red light was perceived exclusively by phyA, red light was perceived by both phyA and phyB, and phyC had little or no role in growth inhibition or coiling of the seminal roots. These results also suggest that other blue-light photoreceptors are involved in growth inhibition of the seminal roots. Fluence-response curve analyses showed that phyA and phyB control very low-fluence response and low-fluence response, respectively, in the seminal roots. This was essentially the same as the growth inhibition previously observed at the late stage of coleoptile development (80 h after germination). The photoperceptive site for the root growth inhibition appeared to be the roots themselves. All three phytochrome species of rice were detected immunochemically in roots. PMID:19744160

Shimizu, Hisayo; Tanabata, Takanari; Xie, Xianzhi; Inagaki, Noritoshi; Takano, Makoto; Shinomura, Tomoko; Yamamoto, Kotaro T

2009-11-01

300

Inhibition of ethylene production in sunflower cell suspensions by the plant growth retardant BAS 111..W: Possible relations to changes in polyamine and cytokinin contents  

Microsoft Academic Search

At a concentration of 10?5 mol · L?1 the triazole-type growth retardant BAS 111..W completely inhibited the transiently elevated ethylene production in the exponential\\u000a growth phase of heterotrophic sunflower cell suspensions. This effect, which could not be restored by adding gibberellin A3, was accompanied by transiently increased levels of 1-aminocyclopropanecarboxylic acid (ACC) in the cells, which was increasingly\\u000a converted to

K. Grossmann; F. Siefert; J. Kwiatkowski; M. Schraudner; C. Langebartels; H. Sandermann

1993-01-01

301

Salirasib inhibits the growth of hepatocarcinoma cell lines in vitro and tumor growth in vivo through ras and mTOR inhibition  

PubMed Central

Background Dysregulation of epidermal growth factor and insulin-like growth factor signaling play important roles in human hepatocellular carcinoma (HCC), leading to frequent activation of their downstream targets, the ras/raf/extracellular signal-regulated kinase (ERK) and the phosphoinositide 3-kinase (PI3K)/Akt/mammalian Target of Rapamycin (mTOR) pathways. Salirasib is an S-prenyl-cysteine analog that has been shown to block ras and/or mTOR activation in several non hepatic tumor cell lines. We investigated in vitro the effect of salirasib on cell growth as well as its mechanism of action in human hepatoma cell lines (HepG2, Huh7, and Hep3B) and its in vivo effect in a subcutaneous xenograft model with HepG2 cells. Results Salirasib induced a time and dose dependent growth inhibition in hepatocarcinoma cells through inhibition of proliferation and partially through induction of apoptosis. A 50 percent reduction in cell growth was obtained in all three cell lines at a dose of 150 ?M when they were cultured with serum. By contrast, salirasib was more potent at reducing cell growth after stimulation with EGF or IGF2 under serum-free conditions, with an IC50 ranging from 60 ?M to 85 ?M. The drug-induced anti-proliferative effect was associated with downregulation of cyclin A and to a lesser extent of cyclin D1, and upregulation of p21 and p27. Apoptosis induction was related to a global pro-apoptotic balance with caspase 3 activation, cytochrome c release, death receptor upregulation, and a reduced mRNA expression of the apoptosis inhibitors cFLIP and survivin. These effects were associated with ras downregulation and mTOR inhibition, without reduction of ERK and Akt activation. In vivo, salirasib reduced tumour growth from day 5 onwards. After 12 days of treatment, mean tumor weight was diminished by 56 percent in the treated animals. Conclusions Our results show for the first time that salirasib inhibits the growth of human hepatoma cell lines through inhibition of proliferation and induction of apoptosis, which is associated with ras and mTOR inhibition. The therapeutic potential of salirasib in human HCC was further confirmed in a subcutaneous xenograft model. PMID:20860815

2010-01-01

302

Dynamic Adaption of Metabolic Pathways during Germination and Growth of Lily Pollen Tubes after Inhibition of the Electron Transport Chain1[W][OPEN  

PubMed Central

Investigation of the metabolome and the transcriptome of pollen of lily (Lilium longiflorum) gave a comprehensive overview of metabolic pathways active during pollen germination and tube growth. More than 100 different metabolites were determined simultaneously by gas chromatography coupled to mass spectrometry, and expressed genes of selected metabolic pathways were identified by next-generation sequencing of lily pollen transcripts. The time-dependent changes in metabolite abundances, as well as the changes after inhibition of the mitochondrial electron transport chain, revealed a fast and dynamic adaption of the metabolic pathways in the range of minutes. The metabolic state prior to pollen germination differed clearly from the metabolic state during pollen tube growth, as indicated by principal component analysis of all detected metabolites and by detailed observation of individual metabolites. For instance, the amount of sucrose increased during the first 60 minutes of pollen culture but decreased during tube growth, while glucose and fructose showed the opposite behavior. Glycolysis, tricarbonic acid cycle, glyoxylate cycle, starch, and fatty acid degradation were activated, providing energy during pollen germination and tube growth. Inhibition of the mitochondrial electron transport chain by antimycin A resulted in an immediate production of ethanol and a fast rearrangement of metabolic pathways, which correlated with changes in the amounts of the majority of identified metabolites, e.g. a rapid increase in ?-aminobutyric acid indicated the activation of a ?-aminobutyric acid shunt in the tricarbonic acid cycle, while ethanol fermentation compensated the reduced ATP production after inhibition of the oxidative phosphorylation. PMID:23660836

Obermeyer, Gerhard; Fragner, Lena; Lang, Veronika; Weckwerth, Wolfram

2013-01-01

303

A role for AMPK in the inhibition of glucose-6-phosphate dehydrogenase by polyunsaturated fatty acids  

SciTech Connect

Both polyunsaturated fatty acids and AMPK promote energy partitioning away from energy consuming processes, such as fatty acid synthesis, towards energy generating processes, such as {beta}-oxidation. In this report, we demonstrate that arachidonic acid activates AMPK in primary rat hepatocytes, and that this effect is p38 MAPK-dependent. Activation of AMPK mimics the inhibition by arachidonic acid of the insulin-mediated induction of G6PD. Similar to intracellular signaling by arachidonic acid, AMPK decreases insulin signal transduction, increasing Ser{sup 307} phosphorylation of IRS-1 and a subsequent decrease in AKT phosphorylation. Overexpression of dominant-negative AMPK abolishes the effect of arachidonic acid on G6PD expression. These data suggest a role for AMPK in the inhibition of G6PD by polyunsaturated fatty acids.

Kohan, Alison B.; Talukdar, Indrani; Walsh, Callee M. [Department of Biochemistry, West Virginia University, Morgantown, WV (United States)] [Department of Biochemistry, West Virginia University, Morgantown, WV (United States); Salati, Lisa M., E-mail: lsalati@hsc.wvu.edu [Department of Biochemistry, West Virginia University, Morgantown, WV (United States)

2009-10-09

304

Rosmarinic acid inhibits lung injury induced by diesel exhaust particles  

Microsoft Academic Search

Epidemiological and experimental studies have suggested that diesel exhaust particles (DEP) may be involved in recent increases in lung diseases. DEP has been shown to generate reactive oxygen species. Intratracheal instillation of DEP induces lung inflammation and edema in mice. Rosmarinic acid is a naturally occurring polyphenol with antioxidative and anti-inflammatory activities. We investigated the effects of rosmarinic acid on

Chiaki Sanbongi; Hirohisa Takano; Naomi Osakabe; Naoko Sasa; Midori Natsume; Rie Yanagisawa; Ken-ichiro Inoue; Yoji Kato; Toshihiko Osawa; Toshikazu Yoshikawa

2003-01-01

305

Bestatin Inhibits Cell Growth, Cell Division, and Spore Cell Differentiation in Dictyostelium discoideum  

PubMed Central

Bestatin methyl ester (BME) is an inhibitor of Zn2+-binding aminopeptidases that inhibits cell proliferation and induces apoptosis in normal and cancer cells. We have used Dictyostelium as a model organism to study the effects of BME. Only two Zn2+-binding aminopeptidases have been identified in Dictyostelium to date, puromycin-sensitive aminopeptidase A and B (PsaA and PsaB). PSA from other organisms is known to regulate cell division and differentiation. Here we show that PsaA is differentially expressed throughout growth and development of Dictyostelium, and its expression is regulated by developmental morphogens. We present evidence that BME specifically interacts with PsaA and inhibits its aminopeptidase activity. Treatment of cells with BME inhibited the rate of cell growth and the frequency of cell division in growing cells and inhibited spore cell differentiation during late development. Overexpression of PsaA-GFP (where GFP is green fluorescent protein) also inhibited spore cell differentiation but did not affect growth. Using chimeras, we have identified that nuclear versus cytoplasmic localization of PsaA affects the choice between stalk or spore cell differentiation pathway. Cells that overexpressed PsaA-GFP (primarily nuclear) differentiated into stalk cells, while cells that overexpressed PsaA?NLS2-GFP (cytoplasmic) differentiated into spores. In conclusion, we have identified that BME inhibits cell growth, division, and differentiation in Dictyostelium likely through inhibition of PsaA. PMID:22345351

Poloz, Yekaterina; Catalano, Andrew

2012-01-01

306

2,3-Dihydroxybenzoic Acid-Containing Nanofiber Wound Dressings Inhibit Biofilm Formation by Pseudomonas aeruginosa  

PubMed Central

Pseudomonas aeruginosa forms biofilms in wounds, which often leads to chronic infections that are difficult to treat with antibiotics. Free iron enhances biofilm formation, delays wound healing, and may even be responsible for persistent inflammation, increased connective tissue destruction, and lipid peroxidation. Exposure of P. aeruginosa Xen 5 to the iron chelator 2,3-dihydroxybenzoic acid (DHBA), electrospun into a nanofiber blend of poly(d,l-lactide) (PDLLA) and poly(ethylene oxide) (PEO), referred to as DF, for 8 h decreased biofilm formation by approximately 75%. This was shown by a drastic decline in cell numbers, from 7.1 log10 CFU/ml to 4.8 log10 CFU/ml when biofilms were exposed to DF in the presence of 2.0 mM FeCl3 6H2O. A similar decline in cell numbers was recorded in the presence of 3.0 mM FeCl3 6H2O and DF. The cells were more mobile in the presence of DHBA, supporting the observation of less biofilm formation at lower iron concentrations. DHBA at MIC levels (1.5 mg/ml) inhibited the growth of strain Xen 5 for at least 24 h. Our findings indicate that DHBA electrospun into nanofibers inhibits cell growth for at least 4 h, which is equivalent to the time required for all DHBA to diffuse from DF. This is the first indication that DF can be developed into a wound dressing to treat topical infections caused by P. aeruginosa. PMID:24449781

Ahire, Jayesh J.

2014-01-01

307

Regulation of glioblastoma stem cells by retinoic acid: role for Notch pathway inhibition  

PubMed Central

It is necessary to understand mechanisms by which differentiating agents influence tumor-initiating cancer stem cells. Toward this end, we investigated the cellular and molecular responses of glioblastoma stem-like cells (GBM-SCs) to all-trans retinoic acid (RA). GBM-SCs were grown as non-adherent neurospheres in growth factor supplemented serum-free medium. RA treatment rapidly induced morphology changes, induced growth arrest at G1/G0 to S transition, decreased cyclin D1 expression and increased p27 expression. Immunofluorescence and western blot analysis indicated that RA induced the expression of lineage-specific differentiation markers Tuj1 and GFAP and reduced the expression of neural stem cell markers such as CD133, Msi-1, nestin and Sox-2. RA treatment dramatically decreased neurosphere-forming capacity, inhibited the ability of neurospheres to form colonies in soft agar and inhibited their capacity to propagate subcutaneous and intracranial xenografts. Expression microarray analysis identified ~350 genes that were altered within 48 h of RA treatment. Affected pathways included retinoid signaling and metabolism, cell-cycle regulation, lineage determination, cell adhesion, cell–matrix interaction and cytoskeleton remodeling. Notch signaling was the most prominent of these RA-responsive pathways. Notch pathway downregulation was confirmed based on the downregulation of HES and HEY family members. Constitutive activation of Notch signaling with the Notch intracellular domain rescued GBM neurospheres from the RA-induced differentiation and stem cell depletion. Our findings identify mechanisms by which RA targets GBM-derived stem-like tumor-initiating cells and novel targets applicable to differentiation therapies for glioblastoma. PMID:21383690

Ying, M; Wang, S; Sang, Y; Sun, P; Lal, B; Goodwin, CR; Guerrero-Cazares, H; Quinones-Hinojosa, A; Laterra, J; Xia, S

2014-01-01

308

Boric acid application guidelines for intergranular corrosion inhibition  

SciTech Connect

A significant fraction of the operating Pressurized Water Reactor steam generators have used or are using boric acid as an inhibitor to control stress corrosion cracking, intergranular attack, or denting. Boric acid is applied on line, or by means of crevice flushing, low power soaks, or a combination of these methods. When boric acid is used, it is important to have knowledge about its chemical and physical properties, its effect on corrosion, and its correct application. The data on these subjects may be found in a diversity of sources, which are often not readily available or convenient to use. In addition, new information has recently become available. This report has been prepared and revised to be comprehensive treatise on boric acid relevant to its application in nuclear steam generators. Relevant boric acid information from 1987--89 has been added to provide the latest available data from laboratory testing and power plant application. 5 figs.

Piskor, S.R. (Westinghouse Electric Corp., Pittsburgh, PA (USA). Nuclear Services Div.)

1990-12-01

309

Root growth inhibition by NH4 in Arabidopsis is mediated  

E-print Network

produce lat- erals along the length of the primary root (Deak & Malamy 2005); hence, the developing root a rudimentary embryonic root, and most growth and differentiation is post-embryonic (Deak & Malamy 2005). During

Kronzucker, Herbert J.

310

Kinetic analysis and mathematical modeling of growth and lactic acid production of Lactobacillus casei var. rhamnosus in milk whey.  

PubMed

Lactobacillus casei is a lactic acid bacterium (LAB) that colonizes diverse ecological niches and that has found broad commercial application. The aim of this study was to characterize the kinetics of biomass production, lactic acid production, and substrate consumption of Lactobacillus casei var. rhamnosus cultured in deproteinized milk whey. Batch culture experiments were performed in an instrumented, 2-L, stirred tank bioreactor using different inoculum concentrations (0.5 to 1.0 g/L) and lactose levels (35 to 70 g/L). The time series of experimental data corresponding to biomass growth, lactose consumption, and lactic acid formation were differentiated to calculate the corresponding kinetic rates. Strong exponentially dependent product inhibition effects were evident at low lactic acid concentrations, and lactic acid production rate was partially associated with biomass growth. A mathematical model is presented that reproduces the experimental lactose, biomass, and lactic acid concentration profiles. PMID:21094727

Alvarez, M M; Aguirre-Ezkauriatza, E J; Ramírez-Medrano, A; Rodríguez-Sánchez, A

2010-12-01

311

Unique Grape Skin Extract Inhibits Prostate Cancer Cell Growth in the Laboratory  

Cancer.gov

Laboratory experiments show that an extract of the skin of muscadine grapes can inhibit growth of prostate cancer cells in the laboratory. Investigators from NCI and their research partners also show that muscadine grape skin extract does not contain significant amounts of resveratrol, another grape skin component that has been widely studied and shown to be of potential benefit in preventing prostate cancer growth.

312

Cooperative Kinetics of Inhibition of Escherichia Coli Growth by Lithium Ions  

Microsoft Academic Search

In the present paper, a model of the cooperative kinetics of inhibition of Escherichia coli cell growth by Li+ ions is developed and experimentally tested. The interaction of various molecular targets for Li+ – transport proteins – in the biomass synthesis provides the basis for the model. An expression that describes the dependence of the specific cell growth rate on

E. V. Evdokimov; S. A. Sharubin

2002-01-01

313

THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN  

EPA Science Inventory

THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN. Harland and Liburdy (1) reported that 1.2-uT, 60-Hz magnetic fields could significantly block the inhibitory action of pharmacological levels of tamoxifen (10-7 M) on the growth of MCF-7 human br...

314

Growth signaling promotes chronological aging in budding yeast by inducing superoxide anions that inhibit quiescence.  

PubMed

Inhibition of growth signaling pathways protects against aging and age-related diseases in parallel with reduced oxidative stress. The relationships between growth signaling, oxidative stress and aging remain unclear. Here we report that in Saccharomyces cerevisiae, alterations in growth signaling pathways impact levels of superoxide anions that promote chronological aging and inhibit growth arrest of stationary phase cells in G0/G1. Factors that decrease intracellular superoxide anions in parallel with enhanced longevity and more efficient G0/G1 arrest include genetic inactivation of growth signaling pathways that inhibit Rim15p, which activates oxidative stress responses, and downregulation of these pathways by caloric restriction. Caloric restriction also reduces superoxide anions independently of Rim15p by elevating levels of H?O?, which activates superoxide dismutases. In contrast, high glucose or mutations that activate growth signaling accelerate chronological aging in parallel with increased superoxide anions and reduced efficiency of stationary phase G0/G1 arrest. High glucose also activates DNA damage responses and preferentially kills stationary phase cells that fail to arrest growth in G0/G1. These findings suggest that growth signaling promotes chronological aging in budding yeast by elevating superoxide anions that inhibit quiescence and induce DNA replication stress. A similar mechanism likely contributes to aging and age-related diseases in complex eukaryotes. PMID:21076178

Weinberger, Martin; Mesquita, Ana; Caroll, Timothy; Marks, Laura; Yang, Hui; Zhang, Zhaojie; Ludovico, Paula; Burhans, William C

2010-10-01

315

Inhibition of prostaglandin synthetase and carrageenan-induced edema by tricyclic analogs of flufenamic acid.  

PubMed

A group of tricyclic analogs of flufenamic acid were tested for their ability to inhibit both the biosynthesis of prostaglandin and carrageenan-induced inflammation of the rat paw. All had activity greater than phenylbutazone as inhibitors of prostaglandin synthetase, with SK&F 22908 being as active as flufenamic acid. The anti-inflammatory activities of these compounds correlated only to a minor degree with the inhibition of prostaglandin biosynthesis. The data support the position that within this series of compounds inhibition of prostaglandin synthetase and non-steroidal antiinflammatory activity, as well as ulcerogenic liability, may be an expression of different mechanisms. PMID:809819

Horodniak, J W; Matz, E D; Walz, D T; Sutton, B M; Berkoff, C E; Zarembo, J E; Bender, A D

1975-08-01

316

Growth Inhibition of Human Gynecologic and Colon Cancer Cells by Phyllanthus watsonii through Apoptosis Induction  

PubMed Central

Phyllanthus watsonii Airy Shaw is an endemic plant found in Peninsular Malaysia. Although there are numerous reports on the anti cancer properties of other Phyllanthus species, published information on the cytotoxicity of P. watsonii are very limited. The present study was carried out with bioassay-guided fractionation approach to evaluate the cytotoxicity and apoptosis induction capability of the P. watsonii extracts and fractions on human gynecologic (SKOV-3 and Ca Ski) and colon (HT-29) cancer cells. P. watsonii extracts exhibited strong cytotoxicity on all the cancer cells studied with IC50 values of ? 20.0 µg/mL. Hexane extract of P. watsonii was further subjected to bioassay-guided fractionation and yielded 10 fractions (PW-1?PW-10). PW-4?PW-8 portrayed stronger cytotoxic activity and was further subjected to bioassay-guided fractionation and resulted with 8 sub-fractions (PPWH-1?PPWH-8). PPWH-7 possessed greatest cytotoxicity (IC50 values ranged from 0.66 – 0.83 µg/mL) and was selective on the cancer cells studied. LC-MS/MS analysis of PPWH-7 revealed the presence of ellagic acid, geranic acid, glochidone, betulin, phyllanthin and sterol glucoside. Marked morphological changes, ladder-like appearance of DNA and increment in caspase-3 activity indicating apoptosis were clearly observed in both human gynecologic and colon cancer cells treated with P. watsonii especially with PPWH-7. The study also indicated that P. watsonii extracts arrested cell cycle at different growth phases in SKOV-3, Ca Ski and HT-29 cells. Cytotoxic and apoptotic potential of the endemic P. watsonii was investigated for the first time by bioassay-guided approach. These results demonstrated that P. watsonii selectively inhibits the growth of SKOV-3, Ca Ski and HT-29 cells through apoptosis induction and cell cycle modulation. Hence, P. watsonii has the potential to be further exploited for the discovery and development of new anti cancer drugs. PMID:22536331

Ramasamy, Sujatha; Abdul Wahab, Norhanom; Zainal Abidin, Nurhayati; Manickam, Sugumaran; Zakaria, Zubaidah

2012-01-01

317

Nucleic acid scavenging polymers inhibit extracellular DNA-mediated innate immune activation without inhibiting anti-viral responses.  

PubMed

Toll-like receptor (TLR) family members, 3, 7 and 9 are key components in initiation and progression of autoimmune disorders such as systemic lupus erythematosus (SLE). These TLRs are often referred to as nucleic acid-sensing TLRs based on their ability to recognize DNAs or RNAs produced by pathogens or damaged cells. During autoimmune disease progression these receptors recognize self nucleic acids as well as self nucleic acid-containing complexes and contribute to inflammatory cytokine production and subsequent enhancement of serum autoantibody levels. We have recently discovered that nucleic-acid scavenging polymers (NASPs) can neutralize the proinflammatory effects of nucleic acids. Here, we begin to explore what effects such NASPs have on normal immune function. We show that such NASPs can inhibit TLR activation without affecting nucleic acid-independent T cell activation. Moreover, we observe that stimulation of immune cells by encapsulated nucleic acids, such as those found in viral particles, is unaffected by NASPs. Thus NASPs only limit the activation of the immune system by accessible extra-cellular nucleic acid and do not engender non-specific immune suppression. These important findings suggest that NASPs represent a new approach toward anti-inflammatory drug development as these agents can potentially be utilized to block overt autoimmune disorders and inflammation while allowing normal immune responses to occur. PMID:23936008

Holl, Eda K; Shumansky, Kara L; Pitoc, George; Ramsburg, Elizabeth; Sullenger, Bruce A

2013-01-01

318

Exogenous growth hormone inhibits growth hormone-releasing factor-induced growth hormone secretion in normal men.  

PubMed Central

Previous studies from this laboratory and by others in rats, monkeys, and humans support the concept that growth hormone (GH) can regulate its own secretion through an autofeedback mechanism. With the availability of human growth hormone-releasing factor (GRF), the possible existence of such a mechanism was reexplored by examining the effect of exogenous GH on the GH response induced by GRF-44-NH2 in six normal men (mean age, 32.4 yr). In all subjects the plasma GH response evoked by GRF-44-NH2 (1 microgram/kg i.v. bolus) was studied before and after 5 d of placebo (1 ml normal saline i.m. every 12 h), and then before and 12 h after 5 d of biosynthetic methionyl human GH (5 U i.m. every 12 h). The GH response to GRF (maximal increment over time 0 value) was significantly inhibited after GH treatment (0-1.3 vs. 2.3-11.2 ng/ml before treatment, P = 0.05), but was not significantly affected by placebo. This impaired pituitary response to GRF persisted for at least 24 h following exogenous GH treatment in two subjects who underwent further study. Serum somatomedin-C concentrations were significantly increased after 5 d of GH treatment (2.66-5.00 vs. 0.92-1.91 U/ml before treatment, P = less than 0.01). The impaired pituitary response to GRF may be mediated indirectly through somatomedin, somatostatin, by a direct effect of GH on the pituitary somatotropes, or by all of these mechanisms. These data suggest that after GH treatment, the blunted GH response to synthetic GRF is not solely a consequence of the inhibition of hypothalamic GRF secretion. PMID:3080472

Rosenthal, S M; Hulse, J A; Kaplan, S L; Grumbach, M M

1986-01-01

319

The attenuated virulence of a Burkholderia cenocepacia?paaABCDE mutant is due to inhibition of quorum sensing by release of phenylacetic acid.  

PubMed

The phenylacetic acid degradation pathway of Burkholderia cenocepacia is active during cystic fibrosis-like conditions and is necessary for full pathogenicity of B. cenocepacia in nematode and rat infection models; however, the reasons for such requirements are unknown. Here, we show that the attenuated virulence of a phenylacetic acid catabolism mutant is due to quorum sensing inhibition. Unlike wild-type B. cenocepacia, a deletion mutant of the phenylacetyl-CoA monooxygenase complex (?paaABCDE) released phenylacetic acid in the medium that favours infection in Caenorhabditis elegans. Addition of phenylacetic acid further decreased the pathogenicity of the ?paaABCDE, which cannot metabolize phenylacetic acid, but did not affect the wild-type, due to phenylacetic acid consumption. In line with reduced detection of acyl-homoserine lactones in spent medium, the ?paaABCDE exhibited transcriptional inhibition of the quorum sensing system cepIR. Phenotypes repressed in ?paaABCDE, protease activity and pathogenicity against C. elegans, increased with exogenous N-octanoyl-L-homoserine lactone. Thus, we demonstrate that the attenuated phenotype of B. cenocepacia ?paaABCDE is due to quorum sensing inhibition by release of phenylacetic acid, affecting N-octanoyl-L-homoserine lactone signalling. Further, we propose that active degradation of phenylacetic acid by B. cenocepacia during growth in cystic fibrosis-like conditions prevents accumulation of a quorum sensing inhibiting compound. PMID:25155974

Pribytkova, Tanya; Lightly, Tasia Joy; Kumar, Brijesh; Bernier, Steve P; Sorensen, John L; Surette, Michael G; Cardona, Silvia T

2014-11-01

320

Growth-inhibiting activities of phenethyl isothiocyanate and its derivatives against intestinal bacteria.  

PubMed

The growth-inhibiting activities of Sinapis alba L. seed-derived materials were examined on the growth of Bifidobacterium bifidum, B. breve, B. longum, Clostridium difficile, C. perfringens, Escherichia coli, Lactobacillus acidophilus, and L. casei. The active component of S. alba seeds was purified using silica gel column chromatography and HPLC and was identified as phenethyl isothiocyanate by various spectroscopic analyses. The antimicrobial activity of phenethyl isothiocyanate varied according to the dose and bacterial strain tested. Phenethyl isothiocyanate strongly inhibited the growth of C. difficile and C. perfringens at 1 mg/disc, and weakly (+) inhibited its growth at 0.1 mg/disc. Furthermore, phenethyl isothiocyanate moderately (++) inhibited the growth of E. coli at a dose of 2 mg/disc, but did not inhibit the growth of bifidobacteria and lactobacilli. Addition of various functional groups to isothiocyanates resulted in selective inhibitory activity against harmful bacteria with low concentrations of aromatic isothiocyanates demonstrating greater inhibitory activity against clostridia and E. coli than aliphatic isothiocyanates. In conclusion, aromatic isothiocyanates containing phenethyl-, benzyl-, and benzoyl-groups might be useful in the development of novel preventive and therapeutic agents against diseases caused by harmful intestinal bacteria. PMID:19799675

Kim, M G; Lee, H S

2009-10-01

321

Salicylic acid inhibits enzymatic browning of fresh-cut Chinese chestnut (Castanea mollissima) by competitively inhibiting polyphenol oxidase.  

PubMed

The inhibitory effect and associated mechanisms of salicylic acid (SA) on the browning of fresh-cut Chinese chestnut were investigated. Shelled and sliced chestnuts were immersed in different concentrations of an SA solution, and the browning of the chestnut surface and interior were inhibited. The activities of polyphenol oxidase (PPO) and peroxidase (POD) extracted from chestnuts were measured in the presence and absence of SA. SA at concentrations higher than 0.3g/L delayed chestnut browning by significantly inhibiting the PPO activity (P<0.01), and the POD activity was not significantly affected (P>0.05). The binding and inhibition modes of SA with PPO and POD, determined by AUTODOCK 4.2 and Lineweaver-Burk plots, respectively, established SA as a competitive inhibitor of PPO. PMID:25308637

Zhou, Dan; Li, Lin; Wu, Yanwen; Fan, Junfeng; Ouyang, Jie

2015-03-15

322

Growth and graviresponsiveness of primary roots of Zea mays seedlings deficient in abscisic acid and gibberellic acid  

NASA Technical Reports Server (NTRS)

The objective of this research was to determine if gibberellic acid (GA) and/or abscisic acid (ABA) are necessary for graviresponsiveness by primary roots of Zea mays. To accomplish this objective we measured the growth and graviresponsiveness of primary roots of seedlings in which the synthesis of ABA and GA was inhibited collectively and individually by genetic and chemical means. Roots of seedlings treated with Fluridone (an inhibitor of ABA biosynthesis) and Ancymidol (an inhibitor of GA biosynthesis) were characterized by slower growth rates but not significantly different gravicultures as compared to untreated controls. Gravicurvatures of primary roots of d-5 mutants (having undetectable levels of GA) and vp-9 mutants (having undectable levels of ABA) were not significantly different from those of wild-type seedlings. Roots of seedlings in which the biosynthesis of ABA and GA was collectively inhibited were characterized by gravicurvatures not significantly different for those of controls. These results (1) indicate that drastic reductions in the amount of ABA and GA in Z. mays seedlings do not significantly alter root graviresponsiveness, (2) suggest that neither ABA nor GA is necessary for root gravicurvature, and (3) indicate that root gravicurvature is not necessarily proportional to root elongation.

Moore, R.; Dickey, K.

1985-01-01

323

Effect of soluble epoxide hydrolase inhibition on epoxyeicosatrienoic acid metabolism in human blood vessels  

E-print Network

blood vessels Xiang Fang,1 Neal L. Weintraub,2,3,4 Ryan B. McCaw,1 Shanming Hu,1 Shawn D. Harmon,1 James on epoxyeicosatrienoic acid metabolism in human blood vessels. Am J Physiol Heart Circ Physiol 287: H2412­H2420, 2004 epoxide hydrolase (sEH) inhibition on epoxyei- cosatrienoic acid (EET) metabolism in intact human blood

Hammock, Bruce D.

324

Gallic acid is the major component of grape seed extract that inhibits amyloid fibril formation.  

PubMed

Many protein misfolding diseases, for example, Alzheimer's, Parkinson's and Huntington's, are characterised by the accumulation of protein aggregates in an amyloid fibrillar form. Natural products which inhibit fibril formation are a promising avenue to explore as therapeutics for the treatment of these diseases. In this study we have shown, using in vitro thioflavin T assays and transmission electron microscopy, that grape seed extract inhibits fibril formation of kappa-casein (?-CN), a milk protein which forms amyloid fibrils spontaneously under physiological conditions. Among the components of grape seed extract, gallic acid was the most active component at inhibiting ?-CN fibril formation, by stabilizing ?-CN to prevent its aggregation. Concomitantly, gallic acid significantly reduced the toxicity of ?-CN to pheochromocytoma12 cells. Furthermore, gallic acid effectively inhibited fibril formation by the amyloid-beta peptide, the putative causative agent in Alzheimer's disease. It is concluded that the gallate moiety has the fibril-inhibitory activity. PMID:24157371

Liu, Yanqin; Pukala, Tara L; Musgrave, Ian F; Williams, Danielle M; Dehle, Francis C; Carver, John A

2013-12-01

325

Ginkgolic acid inhibits HIV protease activity and HIV infection in vitro  

PubMed Central

Summary Background Several HIV protease mutations, which are resistant to clinical HIV protease inhibitors (PIs), have been identified. There is a great need for second-generation PIs with different chemical structures and/or with an alternative mode of inhibition. Ginkgolic acid is a natural herbal substance and a major component of the lipid fraction in the nutshells of the Ginkgo biloba tree. The objective of this study was to determine whether ginkgolic acid could inhibit HIV protease activity in a cell free system and HIV infection in human cells. Material/Methods Purified ginkgolic acid and recombinant HIV-1 HXB2 KIIA protease were used for the HIV protease activity assay. Human peripheral blood mononuclear cells (PBMCs) were used for HIV infection (HIV-1SF162 virus), determined by a p24gag ELISA. Cytotoxicity was also determined. Results Ginkgolic acid (31.2 ?g/ml) inhibited HIV protease activity by 60%, compared with the negative control, and the effect was concentration-dependent. In addition, ginkgolic acid treatment (50 and 100 ?g/ml) effectively inhibited the HIV infection at day 7 in a concentration-dependent manner. Ginkgolic acid at a concentration of up to 150 ?g/ml demonstrated very limited cytotoxicity. Conclusions Ginkgolic acid effectively inhibits HIV protease activity in a cell free system and HIV infection in PBMCs without significant cytotoxicity. Ginkgolic acid may inhibit HIV protease through different mechanisms than current FDA-approved HIV PI drugs. These properties of ginkgolic acid make it a promising therapy for HIV infection, especially as the clinical problem of viral resistance to HIV PIs continues to grow. PMID:22847190

Lü, Jian-Ming; Yan, Shaoyu; Jamaluddin, Saha; Weakley, Sarah M.; Liang, Zhengdong; Siwak, Edward B.; Yao, Qizhi; Chen, Changyi

2012-01-01

326

Fungicides effectively used for growth inhibition of several fungi could induce mycotoxin biosynthesis in toxigenic species.  

PubMed

Seven different commercial fungicides (Aliette, Rovral, Cantus, Ortiva, Luna Experience, Fenomenal and Mancozeb) were tested for their ability to inhibit the growth of the fungal species Penicillium nordicum, Penicillium verrucosum, Verticillium dahliae and Cladosporium sp. In case of the mycotoxigenic strains P. nordicum and P. verrucosum, the biosynthesis of the mycotoxins ochratoxin and citrinin was determined. Interestingly individual fungicides were only able to inhibit the growth of the analyzed fungi to some extent. In case of P. verrucosum the fungicide "Rovral", an iprodion belonging to the substance class of imidazoles, led to a decrease in the growth rate but to a strong induction of mycotoxin biosynthesis as has been described earlier for the strobilurins. Consequently before using a given fungicide to protect crops and enhance storage life, the applicability of this chemical compound should be tested not only for its ability to inhibit fungal growth but also for its effect on level of secondary metabolite biosynthesis. PMID:24036489

Schmidt-Heydt, M; Stoll, D; Geisen, R

2013-09-16

327

Boric acid application guidelines for intergranular corrosion inhibition: Topical report  

SciTech Connect

A significant fraction of the operating Pressurized Water Reactor steam generators have used or are using boric acid as an inhibitor to control stress corrosion cracking, intergranular attack, or denting. Boric acid is applied via crevice flushing, low power soaks, on-line, or using a combination of these methods. When boric acid is used it is important to have knowledge about its chemical and physical properties, its effect on corrosion, and how it should be correctly applied. The data on these subjects may be found in a diversity of sources, which are often not readily available or convenient to use. This document has been prepared to be a comprehensive treatise on boric acid relevant to its application in nuclear steam generators. 49 refs., 31 figs., 16 tabs.

Hermer, R.E.

1987-12-01

328

Epidermal growth factor (EGF) increases the renal amino acid transport capacity in amino acid loaded rats  

Microsoft Academic Search

Summary In anaesthetized adult female rats, the influence of epidermal growth factor (EGF) on renal amino acid handling was investigated in glutamine, arginine (both 50 mg\\/100 g b. wt. per hour), or alanine (90 mg\\/ 100 g b. wt. per hour) loaded animals. Continuous infusions of the three amino acids were followed by an increase in the fractional excretion (FE)

Christian Fleck; J. Pertsch

1998-01-01

329

The inhibition of calcium hydroxyapatite crystal growth by polyphosphonates and polyphosphates  

Microsoft Academic Search

The formation of crystalline calcium hydroxyapatite from solutions of calcium and phosphate ions and the inhibition of calcium hydroxyapatite crystal growth by polyphosphonates and polyphosphates have been studied. The polyphosphonates, disodium ethane-1-hydroxy-1,1-diphosphonate and disodium dichloromethane diphosphonate, are effective inhibitors of calcium hydroxyapatite crystal growth. The polyphosphates are also effective inhibitors of calcium hydroxyapatite crystal growth as long as the required

Marion D. Francis

1969-01-01

330

Study on growth kinetics of phosphoric acid hemihydrate using FBRM  

NASA Astrophysics Data System (ADS)

A novel way for converting crystal mean chord length (MCL) to the mean size (MS) directly was applied in this paper. Using focused beam reflectance measurement (FBRM) technique, the crystal growth process of phosphoric acid hemihydrate was investigated in cooling mode. In order to convert mean chord length to mean size and verify reliability of FBRM data, digital photo-technique in real time was applied in large crystal size range. The results indicated converting constant A between mean chord length and mean size was 7.7 and crystal growth was acted on size-independent growth (Mcabe's ? L law). Combining FBRM in real time with on-line digital photo-technique, the reasons for appearing turn point during phosphoric acid crystallization process were proved to be crystals breakage and agglomeration. The crystal growth rates under different relative supersaturations were determined and the order of crystal growth obtained from the exponent function is 1.07. It can state that the growth of phosphoric acid hemihydrate crystal was mainly controlled by diffusion.

Ma, Yong; Zhu, Jiawen; Chen, Kui; Wu, Yanyang; Chen, Aimei

2009-12-01

331

The influence of retinoic acid on growth and morphology of rat exorbital lacrimal gland acinar cells in culture.  

PubMed

The lacrimal gland transports and metabolizes retinoids and may require vitamin A for normal function. To study effects of retinoic acid on morphology and growth of the lacrimal gland, rat lacrimal acinar cells were cultured in medium with serum or in serum-free medium in the presence or absence of retinoic acid. In the presence of serum, the acinar cells have a somewhat fibroblastic morphology and form confluent layers. Addition of retinoic acid to these cultures causes formation of tubule-like structures. Retinoic acid inhibits the growth of lacrimal cells in medium with serum and the cells do not reach confluence; however, the labeling of the cells with bromodeoxyuridine is not affected by retinoic acid. In serum-free medium the growth of acinar cells is reduced, but their morphology is epithelial and structures resembling secretory domes are present. Retinoic acid causes a further reduction in growth, domes are absent, and cell spreading and enlargement occurs. The effects of retinoic acid on growth and morphology of lacrimal acinar cells in culture are complex and the relevance of these observations to lacrimal function in vivo is unclear; the study demonstrates, however, that these cells are responsive to retinoic acid. PMID:7924408

Ubels, J L; Dennis, M; Lantz, W

1994-06-01

332

Molecular cloning of genetic determinants for inhibition of fungal growth by a fluorescent pseudomonad.  

PubMed Central

Pseudomonas fluorescens HV37a inhibits growth of the fungus Pythium ultimum in vitro. Optimal inhibition is observed on potato dextrose agar, a rich medium. Mutations eliminating fungal inhibition were obtained after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. Mutants were classified by cosynthesis and three groups were distinguished, indicating that a minimum of three genes are required for fungal inhibition. Cosmids that contain wild-type alleles of the genes were identified in an HV37a genomic library by complementation of the respective mutants. This analysis indicated that three distinct genomic regions were required for fungal inhibition. The cosmids containing these loci were mapped by transposon insertion mutagenesis. Two of the cosmids were found to contain at least two genes each. Therefore, at least five genes in HV37a function as determinants of fungal inhibition. Images PMID:3005234

Gutterson, N I; Layton, T J; Ziegle, J S; Warren, G J

1986-01-01

333

Improved inhibition of the histone acetyltransferase PCAF by an anacardic acid derivative.  

PubMed

Several lines of evidence indicate that histone acetyltransferases (HATs) are novel drug targets for treatment of diseases like, for example, cancer and inflammation. The natural product anacardic acid is a starting point for development of small molecule inhibitors of the histone acetyltransferase (HAT) p300/CBP associated factor (PCAF). In order to optimize the inhibitory potency, a binding model for PCAF inhibition by anacardic acid was proposed and new anacardic acid derivatives were designed. Ten new derivatives were synthesized using a novel synthetic route. One compound showed a twofold improved inhibitory potency for the PCAF HAT activity and a twofold improved inhibition of histone acetylation in HEP G2 cells. PMID:20655754

Ghizzoni, Massimo; Boltjes, André; Graaf, Chris de; Haisma, Hidde J; Dekker, Frank J

2010-08-15

334

Citric acid inhibits development of cataracts, proteinuria and ketosis in streptozotocin (type 1) diabetic rats.  

PubMed

Although many fruits such as lemon and orange contain citric acid, little is known about beneficial effects of citric acid on health. Here we measured the effect of citric acid on the pathogenesis of diabetic complications in streptozotocin-induced diabetic rats. Although oral administration of citric acid to diabetic rats did not affect blood glucose concentration, it delayed the development of cataracts, inhibited accumulation of advanced glycation end-products (AGEs) such as N(epsilon)-(carboxyethyl)lysine (CEL) and N(epsilon)-(carboxymethyl)lysine (CML) in lens proteins, and protected against albuminuria and ketosis. We also show that incubation of protein with acetol, a metabolite formed from acetone by acetone monooxygenase, generate CEL, suggesting that inhibition of ketosis by citric acid may lead to the decrease in CEL in lens proteins. These results demonstrate that the oral administration of citric acid ameliorates ketosis and protects against the development of diabetic complications in an animal model of type 1 diabetes. PMID:20117096

Nagai, Ryoji; Nagai, Mime; Shimasaki, Satoko; Baynes, John W; Fujiwara, Yukio

2010-02-26

335

Bibersteinia trehalosi inhibits the growth of Mannheimia haemolytica by a proximity-dependent mechanism.  

PubMed

Mannheimia (Pasteurella) haemolytica is the only pathogen that consistently causes severe bronchopneumonia and rapid death of bighorn sheep (BHS; Ovis canadensis) under experimental conditions. Paradoxically, Bibersteinia (Pasteurella) trehalosi and Pasteurella multocida have been isolated from BHS pneumonic lungs much more frequently than M. haemolytica. These observations suggest that there may be an interaction between these bacteria, and we hypothesized that B. trehalosi overgrows or otherwise inhibits the growth of M. haemolytica. Growth curves (monoculture) demonstrated that B. trehalosi has a shorter doubling time ( approximately 10 min versus approximately 27 min) and consistently achieves 3-log higher cell density (CFU/ml) compared to M. haemolytica. During coculture M. haemolytica growth was inhibited when B. trehalosi entered stationary phase (6 h) resulting in a final cell density for M. haemolytica that was 6 to 9 logs lower than expected with growth in the absence of B. trehalosi. Coculture supernatant failed to inhibit M. haemolytica growth on agar or in broth, indicating no obvious involvement of lytic phages, bacteriocins, or quorum-sensing systems. This observation was confirmed by limited growth inhibition of M. haemolytica when both pathogens were cultured in the same media but separated by a filter (0.4-microm pore size) that limited contact between the two bacterial populations. There was significant growth inhibition of M. haemolytica when the populations were separated by membranes with a pore size of 8 mum that allowed free contact. These observations demonstrate that B. trehalosi can both outgrow and inhibit M. haemolytica growth with the latter related to a proximity- or contact-dependent mechanism. PMID:20038698

Dassanayake, Rohana P; Call, Douglas R; Sawant, Ashish A; Casavant, N Carol; Weiser, Glen C; Knowles, Donald P; Srikumaran, Subramaniam

2010-02-01

336

D-Amino acid oxidase-induced oxidative stress, 3-bromopyruvate and citrate inhibit angiogenesis, exhibiting potent anticancer effects.  

PubMed

Angiogenesis is critical for cancer growth and metastasis. Steps of angiogenesis are energy consuming, while vascular endothelial cells are highly glycolytic. Glioblastoma multiforme (GBM) is a highly vascular tumor and this enhances its aggressiveness. D-amino acid oxidase (DAO) is a promising therapeutic protein that induces oxidative stress upon acting on its substrates. Oxidative stress-energy depletion (OSED) therapy was recently reported (El Sayed et al., Cancer Gene Ther, 19, 1-18, 2012). OSED combines DAO-induced oxidative stress with energy depletion caused by glycolytic inhibitors such as 3-bromopyruvate (3BP), a hexokinase II inhibitor that depleted ATP in cancer cells and induced production of hydrogen peroxide. 3BP disturbs the Warburg effect and antagonizes effects of lactate and pyruvate (El Sayed et al., J Bioenerg Biomembr, 44, 61-79, 2012). Citrate is a natural organic acid capable of inhibiting glycolysis by targeting phosphofructokinase. Here, we report that DAO, 3BP and citrate significantly inhibited angiogenesis, decreased the number of vascular branching points and shortened the length of vascular tubules. OSED delayed the growth of C6/DAO glioma cells. 3BP combined with citrate delayed the growth of C6 glioma cells and decreased significantly the number and size of C6 glioma colonies in soft agar. Human GBM cells (U373MG) were resistant to chemotherapy e.g. cisplatin and cytosine arabinoside, while 3BP was effective in decreasing the viability and disturbing the morphology of U373MG cells. PMID:22802136

El Sayed, S M; El-Magd, R M Abou; Shishido, Y; Yorita, K; Chung, S P; Tran, D H; Sakai, T; Watanabe, H; Kagami, S; Fukui, K

2012-10-01

337

Inhibition of breast and brain cancer cell growth by BCCIPa, an evolutionarily conserved nuclear protein that interacts with BRCA2  

E-print Network

Inhibition of breast and brain cancer cell growth by BCCIPa, an evolutionarily conserved nuclear.2, a region frequently altered in brain and other cancers. Furthermore, expression of BCCIPa inhibits breast and brain cancer cell growth, but fails to inhibit HT1080 cells and a non-transformed human skin ®broblast

Huan, Jun "Luke"

338

Salicylhydroxamic acid (SHAM) inhibition of the dissolved inorganic carbon concentrating process in unicellular green algae  

SciTech Connect

Rates of photosynthetic O{sub 2} evolution, for measuring K{sub 0.5}(CO{sub 2} + HCO{sub 3}{sup {minus}}) at pH 7, upon addition of 50 micromolar HCO{sub 3}{sup {minus}} to air-adapted Chlamydomonas, Dunaliella, or Scenedesmus cells, were inhibited up to 90% by the addition of 1.5 to 4.0 millimolar salicylhydroxamic acid (SHAM) to the aqueous medium. The apparent K{sub i}(SHAM) for Chlamydomonas cells was about 2.5 millimolar, but due to low solubility in water effective concentrations would be lower. Salicylhydroxamic acid did not inhibit oxygen evolution or accumulation of bicarbonate by Scenedesmus cells between pH 8 to 11 or by isolated intact chloroplasts from Dunaliella. Thus, salicylhydroxamic acid appears to inhibit CO{sub 2} uptake, whereas previous results indicate that vanadate inhibits bicarbonate uptake. These conclusions were confirmed by three test procedures with three air-adapted algae at pH 7. Salicylhydroxamic acid inhibited the cellular accumulation of dissolved inorganic carbon, the rate of photosynthetic O{sub 2} evolution dependent on low levels of dissolved inorganic carbon (50 micromolar NaHCO{sub 3}), and the rate of {sup 14}CO{sub 2} fixation with 100 micromolar ({sup 14}C)HCO{sub 3}{sup {minus}}. Salicylhydroxamic acid inhibition of O{sub 2} evolution and {sup 14}CO{sub 2}-fixation was reversed by higher levels of NaHCO{sub 3}. Thus, salicylhydroxamic acid inhibition was apparently not affecting steps of photosynthesis other than CO{sub 2} accumulation. Although salicylhydroxamic acid is an inhibitor of alternative respiration in algae, it is not known whether the two processes are related.

Goyal, A.; Tolbert, N.E. (Michigan State Univ., East Lansing (USA))

1990-03-01

339

Effects of humic acids on the growth of bacteria  

NASA Astrophysics Data System (ADS)

The influence of humic acids of different origins on the growth of bacterial cultures of different taxa isolated from the soil and the digestive tracts of earthworms ( Aporrectodea caliginosa)—habitats with contrasting conditions—was studied. More than half of the soil and intestinal isolates from the 170 tested strains grew on the humic acid of brown coal as the only carbon source. The specific growth rate of the bacteria isolated from the intestines of the earthworms was higher than that of the soil bacteria. The use of humic acids by intestinal bacteria confirms the possibility of symbiotic digestion by earthworms with the participation of bacterial symbionts. Humic acids at a concentration of 0.1 g/l stimulated the growth of the soil and intestinal bacteria strains (66 strains out of 161) on Czapek’s medium with glucose (1 g/l), probably, acting as a regulator of the cell metabolism. On the medium with the humic acid, the intestinal bacteria grew faster than the soil isolates did. The most active growth of the intestinal isolates was observed by Paenibacillus sp., Pseudomonas putida, Delftia acidovorans, Microbacterium terregens, and Aeromonas sp.; among the soil ones were the representatives of the Pseudomonas genus. A response of the bacteria to the influence of humic acids was shown at the strain level using the example of Pseudomonas representatives. The Flexom humin preparation stimulated the growth of the hydrocarbon-oxidizing Acinetobacter sp. bacteria. This effect can be used for creating a new compound with the elevated activity of bacteria that are destroyers of oil and oil products.

Tikhonov, V. V.; Yakushev, A. V.; Zavgorodnyaya, Yu. A.; Byzov, B. A.; Demin, V. V.

2010-03-01

340

Inhibition of cell-free protein synthesis by analogues of aurintricarboxylic acid.  

PubMed

Aurintricarboxylic acid is a potent inhibitor of cell-free protein synthesis by the post-mitochondrial supernatant of chick brain and the translation of mRNA by wheat germ lysate. Comparison of commercially available and chemically synthesized analogues of aurintricarboxylic acid indicates that the unique aurin triphenyl methane ring system and the carboxylic acid groups are both necessary for inhibition of cell-free protein synthesis in both systems. PMID:750075

Kreamer, B L; Anderson, J; Liu, D S; Sparks, M B; Richardson, A

1978-12-01

341

Bithionol inhibits ovarian cancer cell growth In Vitro - studies on mechanism(s) of action  

PubMed Central

Background Drug resistance is a cause of ovarian cancer recurrence and low overall survival rates. There is a need for more effective treatment approaches because the development of new drug is expensive and time consuming. Alternatively, the concept of ‘drug repurposing’ is promising. We focused on Bithionol (BT), a clinically approved anti-parasitic drug as an anti-ovarian cancer drug. BT has previously been shown to inhibit solid tumor growth in several preclinical cancer models. A better understanding of the anti-tumor effects and mechanism(s) of action of BT in ovarian cancer cells is essential for further exploring its therapeutic potential against ovarian cancer. Methods The cytotoxic effects of BT against a panel of ovarian cancer cell lines were determined by Presto Blue cell viability assay. Markers of apoptosis such as caspases 3/7, cPARP induction, nuclear condensation and mitochondrial transmembrane depolarization were assessed using microscopic, FACS and immunoblotting methods. Mechanism(s) of action of BT such as cell cycle arrest, reactive oxygen species (ROS) generation, autotaxin (ATX) inhibition and effects on MAPK and NF-kB signalling were determined by FACS analysis, immunoblotting and colorimetric methods. Results BT caused dose dependent cytotoxicity against all ovarian cancer cell lines tested with IC50 values ranging from 19 ?M – 60 ?M. Cisplatin-resistant variants of A2780 and IGROV-1 have shown almost similar IC50 values compared to their sensitive counterparts. Apoptotic cell death was shown by expression of caspases 3/7, cPARP, loss of mitochondrial potential, nuclear condensation, and up-regulation of p38 and reduced expression of pAkt, pNF-?B, pI?B?, XIAP, bcl-2 and bcl-xl. BT treatment resulted in cell cycle arrest at G1/M phase and increased ROS generation. Treatment with ascorbic acid resulted in partial restoration of cell viability. In addition, dose and time dependent inhibition of ATX was observed. Conclusions BT exhibits cytotoxic effects on various ovarian cancer cell lines regardless of their sensitivities to cisplatin. Cell death appears to be via caspases mediated apoptosis. The mechanisms of action appear to be partly via cell cycle arrest, ROS generation and inhibition of ATX. The present study provides preclinical data suggesting a potential therapeutic role for BT against recurrent ovarian cancer. PMID:24495391

2014-01-01

342

Inhibition of breast cancer growth and metastasis by a biomimetic peptide  

PubMed Central

Metastasis is the main cause of mortality in cancer patients. Though there are many anti-cancer drugs targeting primary tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression, particularly, lymphangiogenesis is pivotal for metastasis in breast cancer. Here we report that a novel collagen IV derived biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis. The peptide inhibits blood and lymphatic endothelial cell viability, migration, adhesion, and tube formation by targeting IGF1R and Met signals. The peptide blocks MDA-MB-231 tumor growth by inhibiting tumor angiogenesis in vivo. Moreover, the peptide inhibits lymphangiogenesis in primary tumors. MDA-MB-231 tumor conditioned media (TCM) was employed to accelerate spontaneous metastasis in tumor xenografts, and the anti-metastatic activity of the peptide was tested in this model. The peptide prevents metastasis to the lungs and lymph nodes by inhibiting TCM-induced lymphangiogenesis and angiogenesis in the pre-metastatic organs. In summary, a novel biomimetic peptide inhibits breast cancer growth and metastasis by blocking angiogenesis and lymphangiogenesis in the pre-metastatic organs as well as primary tumors. PMID:25409905

Lee, Esak; Lee, Seung Jae; Koskimaki, Jacob E.; Han, Zheyi; Pandey, Niranjan B.; Popel, Aleksander S.

2014-01-01

343

Folic acid-mediated inhibition of serum-induced activation of EGFR promoter in colon cancer cells.  

PubMed

Although accumulating evidence suggests a chemopreventive role for folic acid (FA) in colorectal carcinogenesis, the underlying mechanisms are largely unknown. Previously, we reported that supplemental FA inhibits the expression and activation of epidermal growth factor receptor (EGFR) in colon cancer cell lines. To determine the mechanism(s) by which FA affects EGFR function, we have examined whether and to what extent supplemental FA or its metabolites 5-methyltetrahydrofolate (MTF), dihydrofolate (DF), and tetrahydrofolate (TF) will modulate basal and serum-induced activation of the EGFR promoter in the HCT-116 colon cancer cell line. HCT-116 cells were preincubated with or without (control) FA or one of its metabolites (10 microg/ml) for 48 h, transfected with the EGFR promoter luciferase reporter construct, and incubated for 48 h with FA, DF, TF, or 5-MTF in the absence or presence of 10% FBS. Supplemental FA as well as its metabolites markedly inhibited EGFR promoter activity and its methylation status. Exposure of the cells to 10% FBS caused a marked stimulation of EGFR promoter activity and its expression, both of which were greatly abrogated by supplemental FA and 5-MTF. In contrast, serum-induced activation of c-fos promoter activity was unaffected by 5-MTF. The 5-MTF-induced inhibition of serum-mediated stimulation of EGFR promoter activity and EGFR expression was reversed when methylation was inhibited by 5-aza-2'-deoxycytidine. Our data suggest that FA and its metabolite 5-MTF inhibit EGFR promoter activity in colon cancer cells by enhancing methylation. This could partly be responsible for FA-mediated inhibition of growth-related processes in colorectal neoplasia. PMID:15075253

Nagothu, Kiran K; Rishi, Arun K; Jaszewski, Richard; Kucuk, Omer; Majumdar, Adhip P N

2004-09-01

344

The growth response of Alternanthera philoxeroides in a simulated post-combustion emission with ultrahigh [CO2] and acidic pollutants.  

PubMed

Although post-combustion emissions from power plants are a major source of air pollution, they contain excess CO2 that could be used to fertilize commercial greenhouses and stimulate plant growth. We addressed the combined effects of ultrahigh [CO2] and acidic pollutants in flue gas on the growth of Alternanthera philoxeroides. When acidic pollutants were excluded, the biomass yield of A. philoxeroides saturated near 2000 micromol mol(-1) [CO2] with doubled biomass accumulation relative to the ambient control. The growth enhancement was maintained at 5000 micromol mol(-1) [CO2], but declined when [CO2] rose above 1%, in association with a strong photosynthetic inhibition. Although acidic components (SO2 and NO2) significantly offset the CO2 enhancement, the aboveground yield increased considerably when the concentration of pollutants was moderate (200 times dilution). Our results indicate that using excess CO2 from the power plant emissions to optimize growth in commercial green house could be viable. PMID:19269074

Xu, Cheng-Yuan; Griffin, Kevin L; Blazier, John C; Craig, Elizabeth C; Gilbert, Dominique S; Sritrairat, Sanpisa; Anderson, O Roger; Castaldi, Marco J; Beaumont, Larry

2009-07-01

345

Growth Arrest on Inhibition of Nonsense-Mediated Decay Is Mediated by Noncoding RNA GAS5  

PubMed Central

Nonsense-mediated decay is a key RNA surveillance mechanism responsible for the rapid degradation of mRNAs containing premature termination codons and hence prevents the synthesis of truncated proteins. More recently, it has been shown that nonsense-mediated decay also has broader significance in controlling the expression of a significant proportion of the transcriptome. The importance of this mechanism to the mammalian cell is demonstrated by the observation that its inhibition causes growth arrest. The noncoding RNA growth arrest specific transcript 5 (GAS5) has recently been shown to play a key role in growth arrest induced by several mechanisms, including serum withdrawal and treatment with the mTOR inhibitor rapamycin. Here we show that inhibition of nonsense-mediated decay in several human lymphocyte cell lines causes growth arrest, and siRNA-mediated downregulation of GAS5 in these cells significantly alleviates the inhibitory effects observed. These observations hold true for inhibition of nonsense-mediated decay both through RNA interference and through pharmacological inhibition by aminoglycoside antibiotics gentamycin and G418. These studies have important implications for ototoxicity and nephrotoxicity caused by gentamycin and for the proposed use of NMD inhibition in treating genetic disease. This report further demonstrates the critical role played by GAS5 in the growth arrest of mammalian cells. PMID:24319682

Mourtada-Maarabouni, Mirna; Williams, Gwyn T.

2013-01-01

346

Clusterin inhibition using OGX-011 synergistically enhances zoledronic acid activity in osteosarcoma  

PubMed Central

Purpose Despite recent improvements in therapeutic management of osteosarcoma, ongoing challenges in improving the response to chemotherapy warrants new strategies still needed to improve overall patient survival. Among new therapeutic approaches, zoledronic acid (ZOL) represents a promising adjuvant molecule to chemotherapy to limit the osteolytic component of bone tumors. However, ZOL triggers the elevation of heat shock proteins (Hsp), including Hsp27 and clusterin (CLU), which could enhance tumor cell survival and treatment resistance. We hypothesized that targeting CLU using siRNA or the antisense drug, OGX-011, will suppress treatment-induced CLU induction and enhance ZOL-induced cell death in osteosarcoma (OS) cells. Methods The combined effects of OGX-011 and ZOL were investigated in vitro on cell growth, viability, apoptosis and cell cycle repartition of ZOL-sensitive or -resistant human OS cell lines (SaOS2, U2OS, MG63 and MNNG/HOS). Results In OS cell lines, ZOL increased levels of HSPs, especially CLU, in a dose- and time-dependent manner by mechanism including increased HSF1 transcription activity. The OS resistant cells to ZOL exhibited higher CLU expression level than the sensitive cells. Moreover, CLU overexpression protects OS sensitive cells to ZOL-induced cell death by modulating the MDR1 and farnesyl diphosphate synthase expression. OGX-011 suppressed treatment-induced increases in CLU and synergistically enhanced the activity of ZOL on cell growth and apoptosis. These biologic events were accompanied by decreased expression of HSPs, MDR1 and HSF1 transcriptional activity. In vivo, OGX-011, administered 3 times a week (IP, 20mg/kg), potentiated the effect of ZOL (s.c; 50?g/kg), significantly inhibiting tumor growth by 50% and prolonging survival in MNNG/HOS xenograft model compared to ZOL alone. Conclusion These results indicate that ZOL-mediated induction of CLU can be attenuated by OGX-011, with synergistic effects on delaying progression of osteosarcoma. PMID:25138053

Lamoureux, Francois; Baud'huin, Marc; Ory, Benjamin; Guiho, Romain; Zoubeidi, Amina; Gleave, Martin; Heymann, Dominique; Redini, Francoise

2014-01-01

347

Maternal exposure to perfluorinated acids and fetal growth  

Microsoft Academic Search

The widespread detection of perfluorinated acids (PFAs) in humans and known developmental toxicity in animals has raised concern about their potential effects on human reproductive health. Our objective was to determine whether increasing maternal exposure to PFAs is associated with adverse effects on fetal growth and length of gestation in women giving birth in Alberta, Canada. We examined the concentrations

Michele P Hamm; Nicola M Cherry; Emily Chan; Jonathan W Martin; Igor Burstyn

2010-01-01

348

Indole3-butyric acid in plant growth and development  

Microsoft Academic Search

Within the last ten years it has been established by GC-MS thatindole-3-butyric acid (IBA) is an endogenous compound in a variety ofplant species. When applied exogenously, IBA has a variety of differenteffects on plant growth and development, but the compound is stillmainly used for the induction of adventitious roots. Using moleculartechniques, several genes have been isolated that are induced duringadventitious

Jutta Ludwig-Müller

2000-01-01

349

Lifespan Based Pharmacokinetic-Pharmacodynamic Model of Tumor Growth Inhibition by Anticancer Therapeutics  

PubMed Central

Accurate prediction of tumor growth is critical in modeling the effects of anti-tumor agents. Popular models of tumor growth inhibition (TGI) generally offer empirical description of tumor growth. We propose a lifespan-based tumor growth inhibition (LS TGI) model that describes tumor growth in a xenograft mouse model, on the basis of cellular lifespan T. At the end of the lifespan, cells divide, and to account for tumor burden on growth, we introduce a cell division efficiency function that is negatively affected by tumor size. The LS TGI model capability to describe dynamic growth characteristics is similar to many empirical TGI models. Our model describes anti-cancer drug effect as a dose-dependent shift of proliferating tumor cells into a non-proliferating population that die after an altered lifespan TA. Sensitivity analysis indicated that all model parameters are identifiable. The model was validated through case studies of xenograft mouse tumor growth. Data from paclitaxel mediated tumor inhibition was well described by the LS TGI model, and model parameters were estimated with high precision. A study involving a protein casein kinase 2 inhibitor, AZ968, contained tumor growth data that only exhibited linear growth kinetics. The LS TGI model accurately described the linear growth data and estimated the potency of AZ968 that was very similar to the estimate from an established TGI model. In the case study of AZD1208, a pan-Pim inhibitor, the doubling time was not estimable from the control data. By fixing the parameter to the reported in vitro value of the tumor cell doubling time, the model was still able to fit the data well and estimated the remaining parameters with high precision. We have developed a mechanistic model that describes tumor growth based on cell division and has the flexibility to describe tumor data with diverse growth kinetics. PMID:25333487

Mo, Gary; Gibbons, Frank; Schroeder, Patricia; Krzyzanski, Wojciech

2014-01-01

350

Suppression of Spermatogenesis by Bisdichloroacetyldiamines Is Mediated by Inhibition of Testicular Retinoic Acid Biosynthesis  

PubMed Central

The bisdichloroacetyldiamine WIN 18,446 reversibly inhibits spermatogenesis in many species, including humans; however, the mechanism by which WIN 18,446 functions is unknown. As retinoic acid is essential for spermatogenesis, we hypothesized that WIN 18,446 might inhibit retinoic acid biosynthesis from retinol (vitamin A) within the testes by inhibiting the enzyme aldehyde dehydrogenase 1a2 (ALDH1a2). We studied the effect of WIN 18,446 on ALDH1a2 enzyme activity in vitro, and on spermatogenesis and fertility in vivo, in mature male rabbits for 16 weeks. WIN 18,446 markedly inhibited ALDH1a2 enzyme activity in vitro with an IC50 of 0.3 ?M. In vivo, the oral administration of 200 mg/kg WIN 18,446 to male rabbits for 16 weeks significantly reduced intratesticular concentrations of retinoic acid, severely impaired spermatogenesis, and caused infertility. Reduced concentrations of intratesticular retinoic acid were apparent after only 4 weeks of treatment and preceded the decrease in sperm counts and the loss of mature germ cells in tissue samples. Sperm counts and fertility recovered after treatment was discontinued. These findings demonstrate that bisdichloroacetyldiamines such as WIN 18,446 reversibly suppress spermatogenesis via inhibition of testicular retinoic acid biosynthesis by ALDH1a2. These findings suggest that ALDH1a2 is a promising target for the development of a reversible, nonhormonal male contraceptive. PMID:20705791

Amory, John K.; Muller, Charles H.; Shimshoni, Jakob A.; Isoherranen, Nina; Paik, Jisun; Moreb, Jan S.; Amory, David W.; Evanoff, Ryan; Goldstein, Alex S.; Griswold, Michael D.

2012-01-01

351

Antisense gapmers selectively suppress individual oncogenic p73 splice isoforms and inhibit tumor growth in vivo  

PubMed Central

Background Differential mRNA splicing and alternative promoter usage of the TP73 gene results in the expression of multiple NH2-truncated isoforms that act as oncogenes. Abundant levels of these p73 variants in a variety of human cancers correlated with adverse clinical prognosis and response failure to conventional therapies, underscoring their relevance as marker for disease severity and target for cancer intervention. With respect to an equally important role for amino-truncated p73 splice forms (?TAp73) and ?Np73 (summarized as DNp73) in the tumorigenic process, we designed locked nucleic acid (LNA) antisense oligonucleotide (ASO) gapmers against individual species that were complementary to ?Ex2 and ?Ex2/3 splice junctions and a region in exon 3B unique for ?N' and ?N. Results Treatment of cancer cells with these ASOs resulted in a strong and specific reduction of tumorigenic p73 transcripts and proteins, importantly, without abolishing the wild-type p73 tumor suppressor form as observed with p73-shRNA. The specific antisense oligonucleotides rescued cells from apoptosis inhibition due to overexpression of their corresponding amino-truncated p73 isoform and decreased tumor cell proliferation. Furthermore, ASO-116 against ?Ex2/3 coupled to magnetic nanobead polyethyleneimine (MNB/PEI) carriers significantly inhibited malignant melanoma growth, which correlated with a shift in the balance between endogenous TAp73 and ?Ex2/3 towards apoptotic full-length p73. Conclusion Our study demonstrates the successful development of LNA-ASOs that selectively differentiate between the closely related p73 oncoproteins, and provide new tools to further delineate their biological properties in different human malignancies and for therapeutic cancer targeting. PMID:19671150

Emmrich, Stephan; Wang, Weiwei; John, Katja; Li, Wenzhong; Pützer, Brigitte M

2009-01-01

352

Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid  

E-print Network

Ramachandran, Sang Lu, Jun Liu, Li-Qiong Wang, and Ilhan A. Aksay*, Department of Chemical Engineering/mol) hydroxide-to-aluminum ratios. Conversely, citric acid also colloidally stabilizes particles in aqueous Aluminum contamination of soil and groundwater has led to increased research into the speciation

Aksay, Ilhan A.

353

Amurensin G inhibits angiogenesis and tumor growth of tamoxifen-resistant breast cancer via Pin1 inhibition.  

PubMed

Acquired resistance to tamoxifen (TAM) is a serious therapeutic problem among estrogen-receptor-positive breast cancer patients. We have previously reported that TAM-resistant MCF-7 (TAMR-MCF-7) cells have elevated angiogenic potential via Pin1-dependent vascular endothelial growth factor (VEGF) production. Vitis amurensis grape consumed as wine and fruit contains several resveratrol-like stilbenes or oligostilbenes. In this study, we screened for the most active compound to inhibit VEGF production from V. amurensis. Among the tested compounds, amurensin G most potently suppressed VEGF production in TAMR-MCF-7 cells. The enhanced VEGF gene transcription in TAMR-MCF-7 cells was suppressed by amurensin G. Molecular analyses using reporter genes with hypoxia response elements and activator protein-1 (AP-1) elements, and western blots revealed that the activities and the nuclear levels of hypoxia inducible factor-1 (HIF-1)? and AP-1 in TAMR-MCF-7 cells were decreased by amurensin G. Moreover, amurensin G concentration-dependently inhibited protein expression and gene transcription of Pin1 in TAMR-MCF-7 cells, which was dependent on E2F1 inhibition. Chick chorioallantoic membrane assays confirmed that amurensin G had significant antiangiogenic and antitumor growth effects in TMAR-MCF-7 cells. These results demonstrate for the first time that amurensin G may have therapeutic potential for TAM-resistant breast cancer through blocking of Pin1-mediated VEGF gene transcription. PMID:22842120

Kim, Jung-Ae; Kim, Mi Ra; Kim, Ok; Phuong, Nguyen Thi Thuy; Yun, Jieun; Yoon, Jieun; Oh, Won Keun; Bae, KiHwan; Kang, Keon Wook

2012-10-01

354

Acid-catalyzed reactions of epoxides for atmospheric nanoparticle growth.  

PubMed

Although new particle formation accounts for about 50% of the global aerosol production in the troposphere, the chemical species and mechanism responsible for the growth of freshly nucleated nanoparticles remain largely uncertain. Here we show large size growth when sulfuric acid nanoparticles of 4-20 nm are exposed to epoxide vapors, dependent on the particle size and relative humidity. Composition analysis of the nanoparticles after epoxide exposure reveals the presence of high molecular weight organosulfates and polymers, indicating the occurrence of acid-catalyzed reactions of epoxides. Our results suggest that epoxides play an important role in the growth of atmospheric newly nucleated nanoparticles, considering their large formation yields from photochemical oxidation of biogenic volatile organic compounds. PMID:25338124

Xu, Wen; Gomez-Hernandez, Mario; Guo, Song; Secrest, Jeremiah; Marrero-Ortiz, Wilmarie; Zhang, Annie L; Zhang, Renyi

2014-11-01

355

Salicylic acid-induced changes to growth and phenolic metabolism in Matricaria chamomilla plants.  

PubMed

The influence of salicylic acid (SA) doses of 50 and 250 microM, for a period of up to 7 days, on selected physiological aspects and the phenolic metabolism of Matricaria chamomilla plants was studied. SA exhibited both growth-promoting (50 microM) and growth-inhibiting (250 microM) properties, the latter being correlated with decrease of chlorophylls, water content and soluble proteins. In terms of phenolic metabolism, it seems that the higher SA dose has a toxic effect, based on the sharp increase in phenylalanine ammonia-lyase (PAL) activity (24 h after application), which is followed by an increase in total soluble phenolics, lignin accumulation and the majority of the 11 detected phenolic acids. Guaiacol-peroxidase activity was elevated throughout the experiment in 250 microM SA-treated plants. In turn, some responses can be explained by mechanisms associated with oxidative stress tolerance; these mitigate acute SA stress (which is indicated by an increase in malondialdehyde content). However, PAL activity decreased with prolonged exposure to SA, indicating its inhibition. Accumulation of coumarin-related compounds (umbelliferone and herniarin) was not affected by SA treatments, while (Z)- and (E)-2-beta-D: -glucopyranosyloxy-4-methoxycinnamic acids increased in the 250 microM SA-treated rosettes. Free SA content in the rosettes increased significantly only in the 250 microM SA treatment, with levels tending to decrease towards the end of the experiment and the opposite trend was observed in the roots. PMID:18972114

Kovácik, Jozef; Grúz, Jirí; Backor, Martin; Strnad, Miroslav; Repcák, Miroslav

2009-01-01

356

Fatty acid synthase inhibition results in a magnetic resonance-detectable drop in phosphocholine  

PubMed Central

Expression of fatty acid synthase (FASN), the key enzyme in de novo synthesis of long-chain fatty acids (FA), is normally low but increases in cancer. Consequently, FASN is a novel target for cancer therapy. However, because FASN inhibitors can lead to tumor stasis rather than shrinkage, non-invasive methods for assessing FASN inhibition are needed. To this end, we combined 1H, 31P and 13C magnetic resonance spectroscopy (MRS) (i) to monitor the metabolic consequences of FASN inhibition and (ii) to identify MRS-detectable metabolic biomarkers of response. Treatment of PC-3 cells with the FASN inhibitor Orlistat for up to 48 h resulted in inhibition of FASN activity by 70%, correlating with 74% inhibition of FA synthesis. Furthermore, we have determined that FASN inhibition results not only in lower phosphatidylcholine levels, but also in a 59% drop in the phospholipid precursor phosphocholine (PCho). This drop resulted from inhibition in PCho synthesis as a result of a reduction in the cellular activity of its synthetic enzyme choline kinase. The drop in PCho levels following FASN inhibition was confirmed in SKOV-3 ovarian cancer cells treated with Orlistat and in MCF-7 breast cancer cells treated with Orlistat as well as cerulenin. Combining data from all treated cells, the drop in PCho significantly correlated with the drop in de novo synthesized FA levels, identifying PCho as a potential non-invasive MRS-detectable biomarker of FASN inhibition in vivo. PMID:18723500

Ross, James; Najjar, Amer M.; Sankaranarayanapillai, Madhuri; Tong, William P.; Kaluarachchi, Kumaralal; Ronen, Sabrina M.

2008-01-01

357

Nesfatin-1 inhibits gastric acid secretion via a central vagal mechanism in rats  

PubMed Central

Nesfatin-1, a novel hypothalamic peptide, inhibits nocturnal feeding behavior and gastrointestinal motility in rodents. The effects of nesfatin-1 on gastrointestinal secretory function, including gastric acid production, have not been evaluated. Nesfatin-1 was injected into the fourth intracerebral ventricle (4V) of chronically cannulated rats to identify a nesfatin dose sufficient to inhibit food intake. Nesfatin-1 (2 ?g) inhibited dark-phase food intake, in a dose-dependent fashion, for >3 h. Gastric acid production was evaluated in urethane-anesthetized rats. Nesfatin-1 (2 ?g) was introduced via the 4V following endocrine stimulation of gastric acid secretion by pentagastrin (2 ?g·kg?1·h?1 iv), vagal stimulation with 2-deoxy-d-glucose (200 mg/kg sc), or no stimulus. Gastric secretions were collected via gastric cannula and neutralized by titration to determine acid content. Nesfatin-1 did not affect basal and pentagastrin-stimulated gastric acid secretion, whereas 2-deoxy-d-glucose-stimulated gastric acid production was inhibited by nesfatin-1 in a dose-dependent manner. c-Fos immunofluorescence in brain sections was used to evaluate in vivo neuronal activation by nesfatin-1 administered via the 4V. Nesfatin-1 caused activation of efferent vagal neurons, as evidenced by a 16-fold increase in the mean number of c-Fos-positive neurons in the dorsal motor nucleus of the vagus (DMNV) in nesfatin-1-treated animals vs. controls (P < 0.01). Finally, nesfatin-induced Ca2+ signaling was evaluated in primary cultured DMNV neurons from neonatal rats. Nesfatin-1 caused dose-dependent Ca2+ increments in 95% of cultured DMNV neurons. These studies demonstrate that central administration of nesfatin-1, at doses sufficient to inhibit food intake, results in inhibition of vagally stimulated secretion of gastric acid. Nesfatin-1 activates DMNV efferent vagal neurons in vivo and triggers Ca2+ signaling in cultured DMNV neurons. PMID:22723266

Xia, Ze-Feng; Fritze, Danielle M.; Li, Ji-Yao; Chai, Biaoxin; Zhang, Chao

2012-01-01

358

Alpha-secretase inhibition reduces human glioblastoma stem cell growth in vitro and in vivo by inhibiting Notch  

PubMed Central

The Notch pathway is dysregulated and a potential target in glioblastoma multiforme (GBM). Currently available Notch inhibitors block ?-secretase, which is necessary for Notch processing. However, Notch is first cleaved by ?-secretase outside the plasma membrane, via a disintegrin and metalloproteinase–10 and –17. In this work, we used a potent ?-secretase inhibitor (ASI) to test inhibition of glioblastoma growth and inhibition of Notch and of both novel and known Notch targets. Featured in this study are luciferase reporter assays and immunoblot, microarray analysis, chromatin immunoprecipitation (ChIP), quantitative real-time PCR, cell number assay, bromodeoxyuridine incorporation, plasmid rescue, orthotopic xenograft model, and local delivery of treatment with convection-enhanced delivery using nanoparticles, as well as survival, MRI, and ex vivo luciferase assay. A CBF1-luciferase reporter assay as well as an immunoblot of endogenous Notch revealed Notch inhibition by the ASI. Microarray analysis, quantitative real-time PCR, and ChIP of ASI and ?-secretase inhibitor (GSI) treatment of GBM cells identified known Notch pathway targets, as well as novel Notch targets, including YKL-40 and leukemia inhibitory factor. Finally, we found that local nanoparticle delivery of ASIs but not GSIs increased survival time significantly in a GBM stem cell xenograft treatment model, and ASI treatment resulted in decreased tumor size and Notch activity. This work indicates ?-secretase as an alternative to ?-secretase for inhibition of Notch in GBM and possibly other cancers as well, and it identifies novel Notch targets with biologic relevance and potential as biomarkers. PMID:22962413

Floyd, Desiree H.; Kefas, Benjamin; Seleverstov, Oleksandr; Mykhaylyk, Olga; Dominguez, Charli; Comeau, Laurey; Plank, Christian; Purow, Benjamin

2012-01-01

359

mTOR inhibitors block Kaposi sarcoma growth by inhibiting essential autocrine growth factors and tumor angiogenesis  

PubMed Central

Kaposi’s Sarcoma (KS) originates from endothelial cells and it is one of the most overt angiogenic tumors. In Sub-Saharan Africa, where HIV and the Kaposi Sarcoma-associated Herpes Virus (KSHV) are endemic, KS is the most common cancer overall, but model systems for disease study are insufficient. Here we report the development of a novel mouse model of KS where KSHV is retained stably and tumors are elicited rapidly. Tumor growth was sensitive to specific allosteric inhibitors (rapamycin, CCI-779, RAD001) of the pivotal cell growth regulator mTOR. Inhibition of tumor growth was durable up to 130 days and reversible. mTOR blockade reduced VEGF secretion and formation of tumor vasculature. Together, the results demonstrated that mTOR inhibitors exert a direct anti-KS effect by inhibiting angiogenesis and paracrine effectors, suggesting their application as a new treatment modality for KS and other cancers of endothelial origin. PMID:23382046

Roy, Debasmita; Sin, Sang-Hoon; Lucas, Amy; Venkataramanan, Raman; Wang, Ling; Eason, Anthony; Chavakula, Veenadhari; Hilton, Isaac B.; Damania, Blossom; Dittmer, Dirk P.

2013-01-01

360

mTOR inhibitors block Kaposi sarcoma growth by inhibiting essential autocrine growth factors and tumor angiogenesis.  

PubMed

Kaposi sarcoma originates from endothelial cells and it is one of the most overt angiogenic tumors. In Sub-Saharan Africa, where HIV and the Kaposi sarcoma-associated herpesvirus (KSHV) are endemic, Kaposi sarcoma is the most common cancer overall, but model systems for disease study are insufficient. Here, we report the development of a novel mouse model of Kaposi sarcoma, where KSHV is retained stably and tumors are elicited rapidly. Tumor growth was sensitive to specific allosteric inhibitors (rapamycin, CCI-779, and RAD001) of the pivotal cell growth regulator mTOR. Inhibition of tumor growth was durable up to 130 days and reversible. mTOR blockade reduced VEGF secretion and formation of tumor vasculature. Together, the results show that mTOR inhibitors exert a direct anti-Kaposi sarcoma effect by inhibiting angiogenesis and paracrine effectors, suggesting their application as a new treatment modality for Kaposi sarcoma and other cancers of endothelial origin. PMID:23382046

Roy, Debasmita; Sin, Sang-Hoon; Lucas, Amy; Venkataramanan, Raman; Wang, Ling; Eason, Anthony; Chavakula, Veenadhari; Hilton, Isaac B; Tamburro, Kristen M; Damania, Blossom; Dittmer, Dirk P

2013-04-01

361

Effusanin E Suppresses Nasopharyngeal Carcinoma Cell Growth by Inhibiting NF-?B and COX-2 Signaling  

PubMed Central

Rabdosia serra is well known for its antibacterial, anti-inflammatory and antitumor activities, but no information has been available for the active compounds derived from this plant in inhibiting human nasopharyngeal carcinoma (NPC) cell growth. In this study, we isolated and purified a natural diterpenoid from Rabdosia serra and identified its chemical structure as effusanin E and elucidated its underlying mechanism of action in inhibiting NPC cell growth. Effusanin E significantly inhibited cell proliferation and induced apoptosis in NPC cells. Effusanin E also induced the cleavage of PARP, caspase-3 and -9 proteins and inhibited the nuclear translocation of p65 NF-?B proteins. Moreover, effusanin E abrogated the binding of NF-?B to the COX-2 promoter, thereby inhibiting the expression and promoter activity of COX-2. Pretreatment with a COX-2 or NF-?B-selective inhibitor (celecoxib or ammonium pyrrolidinedithiocarbamate) had an additive effect on the effusanin E-mediated inhibition of proliferation, while pretreatment with an activator of NF-?B/COX-2 (lipopolysaccharides) abrogated the effusanin E-mediated inhibition of proliferation. Effusanin E also significantly suppressed tumor growth in a xenograft mouse model without obvious toxicity, furthermore, the expression of p50 NF-?B and COX-2 were down-regulated in the tumors of nude mice. These data suggest that effusanin E suppresses p50/p65 proteins to down-regulate COX-2 expression, thereby inhibiting NPC cell growth. Our findings provide new insights into exploring effusanin E as a potential therapeutic compound for the treatment of human nasopharyngeal carcinoma. PMID:25333664

Zhuang, Mingzhu; Zhao, Mouming; Qiu, Huijuan; Shi, Dingbo; Wang, Jingshu; Tian, Yun; Lin, Lianzhu; Deng, Wuguo

2014-01-01

362

Inhibition of vitamin B12-dependent microbial growth by nitrous oxide  

SciTech Connect

In methionine-free media, nitrous oxide inhibits the growth of an auxotrophic strain of Escherichia coli lacking a cobalamin-independent pathway for the de novo synthesis of methionine. Prototrophic E. coli is similarly inhibited by nitrous oxide if the cobalamin-independent pathway is selectively depressed by sulfanilamide. Nitrous oxide thus effectively inactivates cobalamin-dependent 5-methyltetrahydrofolate-homocysteine methyltransferase in intact bacteria.

Alston, T.A. (Massachusetts General Hospital, Boston (USA))

1991-01-01

363

Peroxisome proliferator-activated receptor ? ligand-induced growth inhibition of human hepatocellular carcinoma  

PubMed Central

Peroxisome proliferator-activated receptor ? (PPAR?) ligands have been implicated in the growth inhibition and differentiation of certain human cancers with diverse tissue origin. In this study, expression of PPAR? in human hepatocellular carcinoma (HCC) and the effect of PPAR? ligands on HCC cells were investigated in vitro using Hep G2, HuH-7, KYN-1 and KYN-2 cell lines. All cell lines were found to express functionally active PPAR? and a marked growth inhibition was induced by thiazolidinedione ligands troglitazone, and pioglitazone as well as with its natural ligand 15-deoxy-?12,14-prostaglandin J 2. The growth inhibitory effect was associated with a dose-dependent inhibition of DNA synthesis, cell cycle progression and ? fetoprotein expression. © 2001 Cancer Research Campaign http://www.bjcancer.com PMID:11401318

Rumi, M A K; Sato, H; Ishihara, S; Kawashima, K; Hamamoto, S; Kazumori, H; Okuyama, T; Fukuda, R; Nagasue, N; Kinoshita, Y

2001-01-01

364

Boric acid reversibly inhibits the second step of pre-mRNA splicing Noam Shomron, Gil Ast  

E-print Network

Boric acid reversibly inhibits the second step of pre-mRNA splicing Noam Shomron, Gil Ast. This investigation demonstrates that the addi- tion of boric acid to an in vitro pre-mRNA splicing reaction causes words: Pre-mRNA splicing; Inhibition; Boric acid; Spliceosome 1. Introduction The spliceosome

Ast, Gil

365

Modification of the Technical Properties of Lactobacillus johnsonii NCC 533 by Supplementing the Growth Medium with Unsaturated Fatty Acids ?  

PubMed Central

The aim of this study was to investigate the influence of supplementing growth medium with unsaturated fatty acids on the technical properties of the probiotic strain Lactobacillus johnsonii NCC 533, such as heat and acid tolerance, and inhibition of Salmonella enterica serovar Typhimurium infection. Our results showed that the membrane composition and morphology of L. johnsonii NCC 533 were significantly changed by supplementing a minimal Lactobacillus medium with oleic, linoleic, and linolenic acids. The ratio of saturated to unsaturated plus cyclic fatty acids in the bacterial membrane decreased by almost 2-fold when minimal medium was supplemented with unsaturated fatty acids (10 ?g/ml). The subsequent acid and heat tolerance of L. johnsonii decreased by 6- and 20-fold when the strain was grown in the presence of linoleic and linolenic acids, respectively, compared with growth in oleic acid (all at 10 ?g/ml). Following acid exposure, significantly higher (P < 0.05) oleic acid content was detected in the membrane when growth medium was supplemented with linoleic or linolenic acid, indicating that saturation of the membrane fatty acids occurred during acid stress. Cell integrity was determined in real time during stressed conditions using a fluorescent viability kit in combination with flow cytometric analysis. Following heat shock (at 62.5°C for 5 min), L. johnsonii was unable to form colonies; however, 60% of the bacteria showed no cell integrity loss, which could indicate that the elevated heat inactivated vital processes within the cell, rendering it incapable of replication. Furthermore, L. johnsonii grown in fatty acid-enriched minimal medium had different adhesion properties and caused a 2-fold decrease in S. enterica serovar Typhimurium UK1-lux invasion of HT-29 epithelial cells compared with bacteria grown in minimal medium alone. This could be related to changes in the hydrophobicity and fluidity of the membrane. Our study shows that technical properties underlying probiotic survivability can be affected by nutrient composition of the growth medium. PMID:21821758

Muller, J. A.; Ross, R. P.; Sybesma, W. F. H.; Fitzgerald, G. F.; Stanton, C.

2011-01-01

366

Noscapine inhibits tumor growth in TMZ-resistant gliomas.  

PubMed

Noscapine, a common oral antitussive agent, has been shown to have potent antitumor activity in a variety of cancers. Treatment of glioblastoma multiforme (GBM) with temozolomide (TMZ), its current standard of care, is problematic because the tumor generally recurs and is then resistant to this drug. We therefore investigated the effects of noscapine on human TMZ-resistant GBM tumors. We found that noscapine significantly decreased TMZ-resistant glioma cell growth and invasion. Using the intracranial xenograft model, we showed that noscapine increased survival of animals with TMZ-resistant gliomas. Thus noscapine can provide an alternative therapeutic approach for the treatment of TMZ-resistant gliomas. PMID:21925789

Jhaveri, Niyati; Cho, Heeyeon; Torres, Shering; Wang, Weijun; Schönthal, Axel H; Petasis, Nicos A; Louie, Stan G; Hofman, Florence M; Chen, Thomas C

2011-12-22

367

Ellagic acid & gallic acid from Lagerstroemia speciosa L. inhibit HIV-1 infection through inhibition of HIV-1 protease & reverse transcriptase activity  

PubMed Central

Background & objectives: Banaba (Lagerstroemia speciosa L.) extracts have been used as traditional medicines and are effective in controlling diabetes and obesity. The aim of this study was to evaluate the anti-HIV property of the extracts prepared from the leaves and stems of banaba, and further purification and characterization of the active components. Methods: Aqueous and 50 per cent ethanolic extracts were prepared from leaves and stems of banaba and were evaluated for cytotoxicity and anti-HIV activity using in vitro reporter gene based assays. Further, three compounds were isolated from the 50 per cent ethanolic extract of banaba leaves using silica gel column chromatography and characterization done by HPLC, NMR and MS analysis. To delineate the mode of action of the active compounds, reverse transcriptase assay and protease assay were performed using commercially available kits. Results: All the extracts showed a dose dependent inhibition of HIV-1-infection in TZM-bl and CEM-GFP cell lines with a maximum from the 50 per cent ethanolic extract from leaves (IC50= 1 to 25 ?g/ml). This observation was confirmed by the virus load (p24) estimation in infected CEM-GFP cells when treated with the extracts. Gallic acid showed an inhibition in reverse transcriptase whereas ellagic acid inhibited the HIV-1 protease activity. Interpretation & conclusions: The present study shows a novel anti-HIV activity of banaba. The active components responsible for anti-HIV activity were gallic acid and ellagic acid, through inhibition of reverse transcriptase and HIV protease, respectively and hence could be regarded as promising candidates for the development of topical anti-HIV-1 agents. PMID:23640562

Nutan; Modi, Manoj; Goel, Tanvi; Das, Tiyasa; Malik, Shweta; Suri, Samiksha; Rawat, Ajay Kumar Singh; Srivastava, Sharad Kumar; Tuli, Rakesh; Malhotra, Swadesh; Gupta, Satish Kumar

2013-01-01

368

Inhibition of the Indole?3?acetic acid?induced Epinastic Curvature in Tobacco Leaf Strips by 2,4?Dichlorophenoxyacetic Acid  

PubMed Central

It has been reported that auxin induces an epinastic growth response in plant leaf tissues. Leaf strips of tobacco (Nicotiana tabacum L. ‘Bright Yellow 2’) were used to study the effects of indole?3?acetic acid (IAA), the principal form of auxin in higher plants, and a synthetic auxin, 2,4?dichlorophenoxyacetic acid (2,4?D), on epinastic leaf curvature. Incubation of leaf strips with 10 µm IAA resulted in a marked epinastic curvature response. Unexpectedly, 2,4?D showed only a weak IAA?like activity in inducing epinasty. Interestingly, the presence of 2,4?D resulted in inhibition of the IAA?dependent epinastic curvature. In vivo Lineweaver–Burk kinetic analysis clearly indicated that the interaction between IAA and 2,4?D reported here is not a result of competitive inhibition. Using kinetic analysis, it was not possible to determine whether the mode of interaction between IAA and 2,4?D was non?competitive or uncompetitive. 2,4?D inhibits the IAA?dependent epinasty via complex and as yet unidentified mechanisms. PMID:12588726

KAWANO, NAKAKO; KAWANO, TOMONORI; LAPEYRIE, FREDERIC

2003-01-01

369

Nitro-linoleic acid inhibits vascular smooth muscle cell proliferation via the Keap1/Nrf2 signaling pathway.  

PubMed

Nitroalkenes, the nitration products of unsaturated fatty acids formed via NO-dependent oxidative reactions, have been demonstrated to exert strong biological actions in endothelial cells and monocytes/macrophages; however, little is known about their effects on vascular smooth muscle cells (VSMCs). The present study examined the role of nitro-linoleic acid (LNO(2)) in the regulation of VSMC proliferation. We observed that LNO(2) inhibited VSMC proliferation in a dose-dependent manner. In addition, LNO(2) induced growth arrest of VSMCs in the G(1)/S phase of the cell cycle with an upregulation of the cyclin-dependent kinase inhibitor p27(kip1). Furthermore, LNO(2) triggered nuclear factor-erythroid 2-related factor 2 (Nrf2) nuclear translocation and activation of the antioxidant-responsive element-driven transcriptional activity via impairing Kelch-like ECH-associating protein 1 (Keap1)-mediated negative control of Nrf2 activity in VSMCs. LNO(2) upregulated the expression of Nrf2 protein levels, but not mRNA levels, in VSMCs. A forced activation of Nrf2 led to an upregulation of p27(kip1) and growth inhibition of VSMCs. In contrast, knock down of Nrf2 using an Nrf2 siRNA approach reversed the LNO(2)-induced upregulation of p27(kip1) and inhibition of cellular proliferation in VSMCs. These studies provide the first evidence that nitroalkene LNO(2) inhibits VSMC proliferation through activation of the Keap1/Nrf2 signaling pathway, suggesting an important role of nitroalkenes in vascular biology. PMID:17468336

Villacorta, Luis; Zhang, Jifeng; Garcia-Barrio, Minerva T; Chen, Xi-lin; Freeman, Bruce A; Chen, Yuqing E; Cui, Taixing

2007-07-01

370

Maslinic acid inhibits the metastatic capacity of DU145 human prostate cancer cells: possible mediation via hypoxia-inducible factor-1? signalling.  

PubMed

Maslinic acid is found in various natural sources, most notably in pomace olive oil, and exerts pro-apoptotic activities in various cancer cells in vitro. In the present study, DU145 human prostate cancer cells were cultured with 0-25 ?m-maslinic acid to examine the effects of maslinic acid on the metastatic capacity of prostate cancer cells. Maslinic acid significantly (P <0.05) inhibited the basal and epidermal growth factor (EGF)-induced migration (27-64 %), invasion (23-60 %) and adhesion (8-40 %) of DU145 cells. Maslinic acid significantly (P <0·05) down-regulated both basal and EGF-stimulated secretion of matrix metalloproteinase (MMP)-9 (25-67 %), MMP-2 (50-86 %), urokinase-type plasminogen activator (uPA, about 100 %), vascular endothelial growth factor (VEGF, 98-100 %) and tissue inhibitors of metalloproteinases (TIMP)-1, as well as expression of uPA receptor (uPAR), intercellular adhesion molecules (22-33 %), vascular cell adhesion molecules (23-46 %) and E-cadherin, whereas it increased TIMP-2 secretion. Maslinic acid dramatically reduced the levels of hypoxia-inducible factor-1? (HIF-1?) protein and mRNA; the reduction was accompanied by reduced stability, nuclear levels and transcriptional activity of HIF-1?. The levels of phospho-Akt and phospho-extracellular signal-related kinase (ERK) were reduced in cells treated with maslinic acid, and the phosphoinositide 3-kinase inhibitor LY294002 and the mitogen-activated protein kinase kinase inhibitor PD98059 reduced HIF-1? levels and VEGF secretion. The results show that maslinic acid markedly inhibited the migration, invasion and adhesion of DU145 prostate cancer cells. Suppressing HIF-1? activation by inhibiting Akt and ERK activation may be part of the mechanism by which maslinic acid inhibited uPAR, E-cadherin, VEGF and MMP expression in DU145 cells. PMID:22716951

Park, So Young; Nho, Chu Won; Kwon, Dae Young; Kang, Young-Hee; Lee, Ki Won; Park, Jung Han Yoon

2013-01-28

371

Erythrocyte aminolevulinic acid dehydratase inhibition by cis-platin  

Microsoft Academic Search

The effect of cis-platin on erythrocyte aminolevulinic acid dehydratase (ALAD) activity was studied in vivo and in vitro. Young male Wistar rats were treated with a single i.p. injection of cis-platin at 2.5, 5.0, and 10.0mg\\/kg dose. In addition, a single i.p. injection of lead nitrate (1.0mg\\/kg dose) was administered as positive control. Experiments in vitro were also performed to

Andrea Trevisan; Matteo Borella-Venturini; Livio Di Marco; Andrea Fabrello; Monica Giraldo; Edoardo Zanetti; Christine Marzano; Dolores Fregona

2004-01-01

372

Novel Approaches to Inhibition of Gastric Acid Secretion  

Microsoft Academic Search

The gastric H,K-adenosine triphosphatase (ATPase) is the primary target for treatment of acid-related diseases. Proton pump\\u000a inhibitors (PPIs) are weak bases composed of two moieties, a substituted pyridine with a primary pKa of about 4.0 that allows selective accumulation in the secretory canaliculus of the parietal cell, and a benzimidazole with\\u000a a second pKa of about 1.0. Protonation of this

George Sachs; Jai Moo Shin; Richard Hunt

2010-01-01

373

Inhibition of a DNA-helicase by peptide nucleic acids  

Microsoft Academic Search

Bis-peptide nucleic acid (bis-PNA) binding results in D-loop formation by strand displacement at comple- mentary homopurine stretches in DNA duplexes. Transcription and replication in intact cells is mediated by multienzymatic complexes involving several proteins other than polymerases. The behaviour of the highly stable clamp structure formed by bis-PNAs has thus far been studied with respect to their capacity to arrest

Lionel Bastide; Paul E. Boehmer; Giuseppe Villani; Bernard Lebleu

1999-01-01

374

Inhibiting transcription of chromosomal DNA with antigene peptide nucleic acids  

Microsoft Academic Search

Synthetic molecules that recognize specific sequences within cellular DNA are potentially powerful tools for investigating chromosome structure and function. Here, we designed antigene peptide nucleic acids (agPNAs) to target the transcriptional start sites for the human progesterone receptor B (hPR-B) and A (hPR-A) isoforms at sequences predicted to be single-stranded within the open complex of chromosomal DNA. We found that

Bethany A Janowski; Kunihiro Kaihatsu; Kenneth E Huffman; Jacob C Schwartz; Rosalyn Ram; Daniel Hardy; Carole R Mendelson; David R Corey

2005-01-01

375

Mutation of Host ?9 Fatty Acid Desaturase Inhibits Brome Mosaic Virus RNA Replication between Template Recognition and RNA Synthesis  

PubMed Central

All positive-strand RNA viruses assemble their RNA replication complexes on intracellular membranes. Brome mosaic virus (BMV) replicates its RNA in endoplasmic reticulum (ER)-associated complexes in plant cells and the yeast Saccharomyces cerevisiae. BMV encodes RNA replication factors 1a, with domains implicated in RNA capping and helicase functions, and 2a, with a central polymerase-like domain. Factor 1a interacts independently with the ER membrane, viral RNA templates, and factor 2a to form RNA replication complexes on the perinuclear ER. We show that BMV RNA replication is severely inhibited by a mutation in OLE1, an essential yeast chromosomal gene encoding ?9 fatty acid desaturase, an integral ER membrane protein and the first enzyme in unsaturated fatty acid synthesis. OLE1 deletion and medium supplementation show that BMV RNA replication requires unsaturated fatty acids, not the Ole1 protein, and that viral RNA replication is much more sensitive than yeast growth to reduced unsaturated fatty acid levels. In ole1 mutant yeast, 1a still becomes membrane associated, recruits 2a to the membrane, and recognizes and stabilizes viral RNA templates normally. However, RNA replication is blocked prior to initiation of negative-strand RNA synthesis. The results show that viral RNA synthesis is highly sensitive to lipid composition and suggest that proper membrane fluidity or plasticity is essential for an early step in RNA replication. The strong unsaturated fatty acid dependence also demonstrates that modulating fatty acid