Inhibition of macromolecular synthesis by caffeine in Clostridium perfringens

1987 ◽  
Vol 33 (7) ◽  
pp. 589-592 ◽  
Author(s):  
Ronald G. Labbe ◽  
Linda L. Nolan
Keyword(s):  
Amino Acids ◽  
Clostridium Perfringens ◽  
Dependent Manner ◽  
Macromolecular Synthesis ◽  
Dose Dependent

Caffeine (2 mg/mL) inhibited the incorporation of [14C]adenine into actively growing cells of Clostridium perfringens NCTC 8679 in a dose-dependent manner. Also reduced by caffeine was incorporation of [14C]thymidine and 14C-labeled amino acids. No effect on guanine, uracil, adenosine, guanosine, or uridine was detected. Actual incorporation of [14C]caffeine or [14C]thymine in control cultures did not occur.

scholarly journals Simonkolleite Coating on Poly(Amino Acids) to Improve Osteogenesis and Suppress Osteoclast Formation in Vitro

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1505 ◽  
Author(s):  
Shuyang Li ◽  
Xingtao Chen ◽  
Xiaomei Wang ◽  
Yi Xiong ◽  
Yonggang Yan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Osteoclast Formation ◽  
Mouse Bone Marrow ◽  
Graft Material ◽  
Dependent Manner ◽  
E Coli ◽  
Ft Ir ◽  
Dose Dependent ◽  
Relative Cell Viability

Zinc can enhance osteoblastic bone formation and stimulate osteogenic differentiation, suppress the differentiation of osteoclast precursor cells into osteoclasts, and inhibit pathogenic bacterial growth in a dose-dependent manner. In this study, simonkolleite, as a novel zinc resource, was coated on poly (amino acids) (PAA) via suspending PAA powder in different concentrations of zinc chloride (ZnCl2) solution, and the simonkolleite-coated PAA (Zn–PAA) was characterized by SEM, XRD, FT-IR and XPS. Zinc ions were continuously released from the coating, and the release behavior was dependent on both the concentration of the ZnCl2 immersing solution and the type of soak solutions (SBF, PBS and DMEM). The Zn–PAA was cultured with mouse bone marrow stem cells (BMSCs) through TranswellTM plates, and the results indicated that the relative cell viability, alkaline phosphatase (ALP) activity and mineralization of BMSCs were significantly higher with Zn–PAA as compared to PAA. Moreover, the Zn–PAA was cultured with RAW264.7 cells, and the results suggested an inhibiting effect of Zn–PAA on the cell differentiation into osteoclasts. In addition, Zn–PAA exhibited an antibacterial activity against both S. aureus and E. coli. These findings suggest that simonkolleite coating with certain contents could promote osteogenesis, suppress osteoclast formation and inhibit bacteria, indicating a novel way of enhancing the functionality of synthetic bone graft material and identifying the underline principles for designing zinc-containing bone grafts.

Adenosine triphosphate regulates the activity of guinea pig Cav1.2 channel by direct binding to the channel in a dose-dependent manner

2014 ◽  
Vol 306 (9) ◽  
pp. C856-C863 ◽  
Author(s):  
Rui Feng ◽  
Jianjun Xu ◽  
Etsuko Minobe ◽  
Asako Kameyama ◽  
Lei Yang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Guinea Pig ◽  
Terminal Region ◽  
Atp Binding ◽  
Dependent Manner ◽  
Channel Activity ◽  
Fusion Peptides ◽  
Patch Clamp Technique ◽  
Binding Effect ◽  
Dose Dependent

The present study is to investigate the mechanism by which ATP regulates Cav1.2 channel activity. Ventricular tissue was obtained from adult guinea pig hearts using collagenase. Ca2+ channel activity was monitored using the patch-clamp technique. Proteins were purified using wheat germ agglutinin-Sepharose, and the concentration was determined using the Coomassie brilliant blue technique. ATP binding to the Cav1.2 channel was examined using the photoaffinity method. EDA-ATP-biotin maintains Ca2+ channel activity in inside-out membrane patches. ATP directly bound to the Cav1.2 channel in a dose-dependent manner, and at least two molecules of ATP bound to one molecule of the Cav1.2 channel. Low levels of calmodulin (CaM) increased ATP binding to the Cav1.2 channel, but higher levels of CaM decreased ATP binding to the Cav1.2 channel. In addition, Ca2+ was another regulator for ATP binding to the Cav1.2 channel. Furthermore, ATP bound to GST-fusion peptides of NH2-terminal region (amino acids 6–140) and proximal COOH-terminal region (amino acids 1,509–1,789) of the main subunit (α1C) of the Cav1.2 channel. Our data suggest that ATP might regulate Cav1.2 channel activity by directly binding to the Cav1.2 channel in a dose-dependent manner. In addition, the ATP-binding effect to the Cav1.2 channel was both CaM- and Ca2+ dependent.

scholarly journals Serum Metabolites Responding in a Dose-Dependent Manner to the Intake of a High-Fat Meal in Normal Weight Healthy Men Are Associated with Obesity

Metabolites ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 392
Author(s):  
Ueli Bütikofer ◽  
David Burnand ◽  
Reto Portmann ◽  
Carola Blaser ◽  
Flurina Schwander ◽  
...  
Keyword(s):  
Amino Acids ◽  
Branched Chain Amino Acids ◽  
Normal Weight ◽  
Dependent Manner ◽  
Metabolic Dysfunction ◽  
High Fat ◽  
Randomized Controlled ◽  
Two Factors ◽  
Branched Chain ◽  
Dose Dependent

Although the composition of the human blood metabolome is influenced both by the health status of the organism and its dietary behavior, the interaction between these two factors has been poorly characterized. This study makes use of a previously published randomized controlled crossover acute intervention to investigate whether the blood metabolome of 15 healthy normal weight (NW) and 17 obese (OB) men having ingested three doses (500, 1000, 1500 kcal) of a high-fat (HF) meal can be used to identify metabolites differentiating these two groups. Among the 1024 features showing a postprandial response, measured between 0 h and 6 h, in the NW group, 135 were dose-dependent. Among these 135 features, 52 had fasting values that were significantly different between NW and OB men, and, strikingly, they were all significantly higher in OB men. A subset of the 52 features was identified as amino acids (e.g., branched-chain amino acids) and amino acid derivatives. As the fasting concentration of most of these metabolites has already been associated with metabolic dysfunction, we propose that challenging normal weight healthy subjects with increasing caloric doses of test meals might allow for the identification of new fasting markers associated with obesity.

scholarly journals An E x Vivo Model of Oxidatively Stressed Red Blood Cells Demonstrates a Role for Exogenous Amino Acids in Enhancing Red Blood Cell Function and Morphology

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 922-922
Author(s):  
Heather N. Colvin ◽  
Elmira Alipour ◽  
Jordan Buzzett ◽  
Glen Marrs ◽  
Daniel B. Kim-Shapiro ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Amino Acids ◽  
Amino Acid ◽  
Antioxidant Capacity ◽  
Dependent Manner ◽  
Red Cell ◽  
Intracellular Ros ◽  
Amino Acid Precursors ◽  
The Impact ◽  
Dose Dependent

Abstract The capacity of mature red blood cells (RBCs) to respond to oxidative stress is limited due to lack of a full complement of organelles and as such, when faced with an oxidative environment, they rely on their endogenous antioxidant capacity (including superoxide dismutase, catalase, peroxiredoxin and glutathione) to protect against cellular damage. Low blood glutathione activity has been reported in several red cell disorders leading to increased oxidative stress. Targeting oxidative stress has thus been proposed as a secondary treatment in multiple anemia-causing diseases, such as sickle cell disease (SCD) and malaria, although its overall efficacy remains unclear. As glutathione itself is not permeable through the RBC membrane, treatment with cell-permeable amino acid precursors of glutathione (glutamine, cysteine and/or glycine) is a potential strategy to expand the RBC's antioxidant capacity and alleviate oxidative stress. Indeed, L-glutamine has recently been approved as a therapeutic for SCD, although the mechanistic basis for its effect is not clear. To fill this gap in our understanding, we performed detailed characterization of biophysical phenotype, morphology, and intracellular redox environment of oxidatively stressed RBCs in environments with varying amounts of available precursor amino acids. To assess the impact of exogenous amino acid precursors on the RBC's glutathione antioxidant capacity, we exposed mature RBCs from healthy adults to hydrogen peroxide (H 2O 2) and co-incubated with media that included glutamine, cysteine, and/or glycine. As catalase has the ability to scavenge high levels of exogenously fluxed H 2O 2, we performed these experiments using sodium azide to block catalase activity, enabling us to model oxidatively stressed RBCs. We performed osmotic gradient ektacytometry to quantify RBC deformability and hydration status, and assessed RBC morphology using osmotic-adjusted fixation techniques and scanning electron microscopy. As previously documented, H 2O 2 exposure in sodium azide-treated healthy RBCs was associated with decreased deformability, decreased hydration and increased numbers of echinocytes in a dose-dependent manner. We monitored red cell phenotypic changes following co-incubation with glutamine, cysteine, and/or glycine individually and in combination to test whether these amino acids extended the RBC's antioxidant abilities and contributed to improved function and morphology. We found that supplementation with all three amino acids in combination significantly improved both deformability and hydration of H 2O 2-stressed RBCs, as opposed to treatment with glutamine alone. To directly assess whether the exogenous amino acids were in fact contributing to less intracellular oxidative stress in RBCs, we quantified intracellular reactive oxygen species (ROS) using 2', 7' -dichlorofluorescein diacetate (DCFDA), a cell permeable dye used to measure ROS production. As expected, H 2O 2 exposure alone was associated with elevated intracellular ROS inside RBCs in both a time- and dose-dependent manner. Supplementation with the three amino acid cocktail during H 2O 2 stress resulted in a reduction in the level of intracellular ROS activity. In summary, we documented that exogenous added amino acids reduce oxidative damage in RBCs and we hypothesize that this protection occurs via the glutathione antioxidant pathways. In future studies, we plan to investigate the impact of exogenous amino acids on sickled and irreversibly sickled RBCs (ISCs) in the context of SCD, and on uninfected and infected RBCs in the context of malaria. Disclosures Kim-Shapiro: Beverage Operations LLC: Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: co-inventor on a patent related to the use of nitrite under cardiovascular conditions, and a co-author on patents related to treatment of hemolysis.

Human D-Tyr-tRNATyr deacylase contributes to the resistance of the cell to D-amino acids

2008 ◽  
Vol 417 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Gen Zheng ◽  
Wei Liu ◽  
Yanhua Gong ◽  
Hongbo Yang ◽  
Bin Yin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nuclear Envelope ◽  
Mammalian Cells ◽  
Nuclear Accumulation ◽  
Nuclear Pore ◽  
Dependent Manner ◽  
High Concentration ◽  
Cellular Resistance ◽  
Trna Editing ◽  
Dose Dependent

DTD (D-Tyr-tRNATyr deacylase) is known to be able to deacylate D-aminoacyl-tRNAs into free D-amino acids and tRNAs and therefore contributes to cellular resistance against D-amino acids in Escherichia coli and yeast. We have found that h-DTD (human DTD) is enriched in the nuclear envelope region of mammalian cells. Treatment of HeLa cells with D-Tyr resulted in nuclear accumulation of tRNATyr. D-Tyr treatment and h-DTD silencing caused tRNATyr downregulation. Furthermore, inhibition of protein synthesis by D-Tyr treatment and h-DTD silencing were also observed. D-Tyr, D-Asp and D-Ser treatment inhibited mammalian cell viability in a dose-dependent manner; overexpression of h-DTD decreased the inhibition rate, while h-DTD-silenced cells became more sensitive to the D-amino acid treatment. Our results suggest that h-DTD may play an important role in cellular resistance against D-amino acids by deacylating D-aminoacyl tRNAs at the nuclear pore. We have also found that m-DTD (mouse DTD) is specifically enriched in central nervous system neurons, its nuclear envelope localization indicates that D-aminoacyl-tRNA editing may be vital for the survival of neurons under high concentration of D-amino acids.

scholarly journals Effect of hydrolysed egg protein on brain tryptophan availability

2011 ◽  
Vol 105 (4) ◽  
pp. 611-617 ◽  
Author(s):  
E. Siobhan Mitchell ◽  
Marieke Slettenaar ◽  
Frits Quadt ◽  
Timo Giesbrecht ◽  
Joris Kloek ◽  
...  
Keyword(s):  
Amino Acids ◽  
Milk Protein ◽  
Low Dose ◽  
Protein Hydrolysate ◽  
Dependent Manner ◽  
Double Blind ◽  
Egg Protein ◽  
Cognitive Benefits ◽  
Dose Dependent ◽  
Different Doses

Serotonin synthesis critically depends on plasma levels of tryptophan (TRP). Earlier studies have shown that for mood and cognitive benefits to occur, the ratio between TRP and other large neutral amino acids (LNAA) has to be increased by approximately 40 %. The present study investigated the dose-dependent effects of a TRP-rich hydrolysed protein (egg-protein hydrolysate, EPH) on the plasma TRP:LNAA. Moreover, it was investigated whether EPH could increase TRP:LNAA in the presence of 2 g of milk protein (MP). In a randomised double-blind crossover design, plasma amino acids were measured every 30 min for 3·5 h after ingestion of a drink containing either three different doses of 4, 8 and 12 g EPH containing 270, 560 or 800 mg of TRP, respectively, the combination of 4 g EPH and 2 g MP (74 mg TRP), or 4 g MP (148 mg TRP) in twenty healthy subjects with a mean age of 52 years. All three EPH doses caused significant increases of TRP:LNAA above 40 % at 30, 60 and 90 min after consumption in a dose-dependent manner. Compared with the 4 g EPH, the increase in TRP:LNAA in the 4 g EPH with 2 g MP condition was significantly lower at 60 min (63 v. 44 %, P < 0·001) and did not differ significantly at 90 min (58 v. 53 %, P>0·05). The present study showed that a low dose of 4 g EPH with even the addition of 2 g MP was sufficient to increase the ratio of TRP:LNAA above 40 %. Thus, EPH offers a viable ingredient to increase TRP availability.

Changes in intracellular potentials and ionic currents of the mollusk and activity of Cl--channels under exposure to some inhibitory amino acids and new litium-containing compounds of them

2015 ◽  
Vol 13 (3) ◽  
pp. 39-47 ◽  
Author(s):  
Petr Dmitrievich Shabanov ◽  
Anatoliy Ivanovich Vislobokov ◽  
Georgiy Nolianovich Shilov ◽  
P M Bulay ◽  
A P Lugovskii
Keyword(s):  
Amino Acids ◽  
Chloride Channels ◽  
Impulse Activity ◽  
Ionic Current ◽  
Ionic Currents ◽  
Dependent Manner ◽  
Cl Channels ◽  
Ganglion Neurons ◽  
Inhibitory Amino Acids ◽  
Dose Dependent

The Changes of membrane rest potential (RP), action potential (AP), impulse activity (IA) as well as sodium, calcium and potassium ionic currents in neurons of isolated central nervous system of the Planorbarius corneus mollusk (pedal ganglia) under the extracellular action of inhibitory amino acids GABA, glycine and β-alanine and their litium-containing derivatives (LCD) in 0.1, 1 and 5 mM concentrations have been studied using a microelectrode technique. They induced the same dose-dependent and irreversible depolarization of neurons on 2-10 mV accompanied by increase of AP frequency, prolongation of their duration and decrease of summmerized ionic currents (dV/dt). According to degree of depolarization, the drugs were placed in the following range in decreasing activity: compound 3 > compound 2 > compound 1. In identified pedal ganglion neurons (PPed1), compound 3 in contrast to other compounds induced hyperpolarization by 2-10 mV and blocked impulse activity. The amplitude of sodium and calcium channels was decreased by 7-15 %, in the same degree after application of all compounds exposed in concentration of 5 mM. Efflux potassium ionic currents were increased in dose-dependent manner and irreversibly about by 3-7 % assessed on amplitude indexes without changes in kinetic parameters after application of LCD. Therefore, the decrease of ionic current amplitudes was due to both depolarization of neurons and direct action of LCD on ionic channels. Thus, LCD possess membranotropic activity and can modulate functional state of neurons. In the study of chloride channels in cells culture of rat glioma C6 in vitro by patch-clamp method, GABA, glycine, β-alanine and their LCD 10 µM/l activated chloride channels, shifting equiliblium membrane potential of glioma cells from -90… -70 mV to -55... -60 mV. All compounds (transmitters and LCD) were placed in the following range: glycine > GABA > β-alanine and compound 1 > compound 3 > compound 2 according to descending activity. Therefore, the most active compounds activating Cl--channels were glycine and compound 1 (LCD). Glycine was shown to be coagonist GABA receptors and its litium salt possessed significant membranotropic activity.

scholarly journals Clostridium perfringens Enterotoxin Fragment Removes Specific Claudins from Tight Junction Strands

1999 ◽  
Vol 147 (1) ◽  
pp. 195-204 ◽  
Author(s):  
Noriyuki Sonoda ◽  
Mikio Furuse ◽  
Hiroyuki Sasaki ◽  
Shigenobu Yonemura ◽  
Jun Katahira ◽  
...  
Keyword(s):  
Tight Junction ◽  
Clostridium Perfringens ◽  
Time Course ◽  
Morphological Changes ◽  
Dependent Manner ◽  
Clostridium Perfringens Enterotoxin ◽  
Dose Dependent ◽  
I Cells ◽  
Mdck I ◽  
Good Agreement

Claudins, comprising a multigene family, constitute tight junction (TJ) strands. Clostridium perfringens enterotoxin (CPE), a single ∼35-kD polypeptide, was reported to specifically bind to claudin-3/RVP1 and claudin-4/CPE-R at its COOH-terminal half. We examined the effects of the COOH-terminal half fragment of CPE (C-CPE) on TJs in L transfectants expressing claudin-1 to -4 (C1L to C4L, respectively), and in MDCK I cells expressing claudin-1 and -4. C-CPE bound to claudin-3 and -4 with high affinity, but not to claudin-1 or -2. In the presence of C-CPE, reconstituted TJ strands in C3L cells gradually disintegrated and disappeared from their cell surface. In MDCK I cells incubated with C-CPE, claudin-4 was selectively removed from TJs with its concomitant degradation. At 4 h after incubation with C-CPE, TJ strands were disintegrated, and the number of TJ strands and the complexity of their network were markedly decreased. In good agreement with the time course of these morphological changes, the TJ barrier (TER and paracellular flux) of MDCK I cells was downregulated by C-CPE in a dose-dependent manner. These findings provided evidence for the direct involvement of claudins in the barrier functions of TJs.

scholarly journals Mapping the epithelial-cell-binding domain of the Aggregatibacter actinomycetemcomitans autotransporter adhesin Aae

Microbiology ◽  
2010 ◽  
Vol 156 (11) ◽  
pp. 3412-3420 ◽  
Author(s):  
Daniel H. Fine ◽  
Jeffrey B. Kaplan ◽  
David Furgang ◽  
Maribasappa Karched ◽  
Kabilan Velliyagounder ◽  
...  
Keyword(s):  
Amino Acids ◽  
Epithelial Cells ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Binding Domain ◽  
Full Length ◽  
Dependent Manner ◽  
Passenger Domain ◽  
E Coli ◽  
Pre Treatment ◽  
Dose Dependent

The Gram-negative periodontopathogen Aggregatibacter actinomycetemcomitans (Aa) binds selectively to buccal epithelial cells (BECs) of human and Old World primates by means of the outer-membrane autotransporter protein Aae. We speculated that the exposed N-terminal portion of the passenger domain of Aae would mediate binding to BECs. By using a series of plasmids that express full-length or truncated Aae proteins in Escherichia coli, we found that the BEC-binding domain of Aae was located in the N-terminal surface-exposed region of the protein, specifically in the region spanning amino acids 201–284 just upstream of the repeat region within the passenger domain. Peptides corresponding to amino acids 201–221, 222–238 and 201–240 were synthesized and tested for their ability to reduce Aae-mediated binding to BECs based on results obtained with truncated Aae proteins expressed in E. coli. BEC-binding of E. coli expressing Aae was reduced by as much as 50 % by pre-treatment of BECs with a 40-mer peptide (201–240; P40). Aae was also shown to mediate binding to cultured human epithelial keratinocytes (TW2.6), OBA9 and TERT, and endothelial (HUVEC) cells. Pre-treatment of epithelial cells with P40 resulted in a dose-dependent reduction in binding and reduced the binding of both full-length and truncated Aae proteins expressed in E. coli, as well as Aae expressed in Aa. Fluorescently labelled P40 peptides reacted in a dose-dependent manner with BEC receptors. We propose that these proof-of-principle experiments demonstrate that peptides can be designed to interfere with Aa binding mediated by host-cell receptors specific for Aae adhesins.

Thyroid hormones and metamorphosis of sea urchin larvae

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S52-S53 ◽  
Author(s):  
Takashi Suyemitsu
Keyword(s):  
Amino Acids ◽  
Thyroid Hormones ◽  
Sea Urchin ◽  
The Other ◽  
Dependent Manner ◽  
Other Hand ◽  
Initial Stage ◽  
Adult Rudiment ◽  
Dose Dependent ◽  
Hemicentrotus Pulcherrimus

Algae were supplied continuously to four-armed pluteus larvae of the sea urchin Hemicentrotus pulcherrimus until the adult rudiment reached stage g, which is the initial stage of rudiment formation (Chino et al., 1994) After stage g, one group of larvae was reared without the addition of algae for comparison of the development of the adult rudiment with that in larvae given algae. Three days later, only 9.1 ± 0.3% of larvae without algae had reached stage j, while 76.8 ± 0.6% of larvae with algae had reached a stage beyond j, which indicates the formation of the complete adult rudiment.When larvae at rudiment stage g were reared in a medium supplemented with T4 or its derivatives, such as T3, 3,3′,5′-L-triiodothyronine (rT3) or triiodothyropropionine (Tp3), in place of algae, the adult rudiment developed in a dose-dependent manner. T4 was the most effective and induced formation of the adult rudiment in more than 70% of specimens at 1 nM and in almost 100% at 100 nM. T3 was one-tenth as effective as T4. Other derivatives were still less effective. On the other hand, casein, ovalbumin, tyrosine and a mixture of 20 amino acids had no effect on the development of larvae and adult rudiments, suggesting that they were not available as nutrients and sources of thyroid hormones.

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