• BMB Reports
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• v.44 no.3
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• pp.205-210
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• 2011

Insulin has antiapoptotic activity in various cell types. However, the signaling pathways underlying the antiapoptotic activity of insulin is not yet known. This study was conducted to determine if cAMP affects the antiapoptotic activity of insulin and the activity of PI3K and ERK in CHO cells expressing human insulin receptors (CHO-IR). Insulin-stimulated ERK activity was completely suppressed by cAMP-elevating agents like as pertussis toxin (Ptx) and cholera toxin (Ctx) after 4 h treatment. Insulin-stimulated PKB/Akt activity was not affected at all. Ptx treatment together with insulin increased the number of apoptotic cells and the degree of DNA fragmentation. Ctx or 8-br-cAMP treatment also increased the number of apoptotic cells and stimulated the cleavage of caspase-3 and the hydrolysis of PARP. Taken together, cAMP antagonizes the antiapoptotic activity of insulin and the main target molecule of cAMP in this process is likely ERK, not PI3K-dependent PKB/Akt.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.11-19
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• 1992

To find out an effective way of treating the toxicity of cadmium, concentrations of $K^+,\;Ca^{2+}$ and c-AMP, and activities of GOT and GPT in blood of rats were determined at definite time intervals after administration of cadmium to rats. Cadmium caused more decrease of $Ca^{2+}$ concentration than $K^+$ concentration but increases of GOT and GPT activities and of c-AMP concentrations. The decreased concentration of $Ca^{2+}$ was not recovered by selenium or metallothionein. However, the increased activities of GOT and GPT, and the c-AMP concentration were down regulated remarkably by selenium but not by metallothionein. These results suggested that selenium might have the compensate effects concerning toxic index against cadmium such as increases of GOT and GPT activities, and of c-AMP concentration.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.54-54
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• 2021

The Melanoma Research Coalition reported melanoma affects humans of various races. This study was conducted to confirm the inhibitory effect of melanogenesis in B16 F10 cells of Nypa fruticans Wurmb of ethyl acetate fraction (NEF). Nypa fruticans Wurmb is an important component of the East Asian mangrove vegetation. It belongs to Araceae family. Traditionally, N. fruticans was used to treat various diseases such as asthma, sore throat, liver disease, a pain reliever, and can also be used as sedative and carminative. The present study, the inhibitory effect on melanogenesis was determined by Western blotting and RT-qPCR. The level of expression of tyrosinase, TRP-1, and TRP-2 is regulated by microphthalmia-associated transcription factor (MITF) and cAMP, and cAMP affects the activity of protein kinase A (PKA). Activated PKA stimulates the phosphorylation of cAMP-reactive element-binding protein (CREB) in the nucleus, thereby increasing the amount of MITF expression and enhancing melanogenesis. Western blotting and RT-qPCR analysis showed that NEF treatment decreased the expression of tyrosinase. Similarly, TRP-1 and TRP-2 levels were decreased, which were decreased significantly at compared with the untreated control. Also, NEF attenuated the IBMX mediated increase in the intracellular cAMP level and the phosphorylation of PKA. In conclusion, NEF significantly inhibited the expressions of melanogenesis through cAMP/PKA/CREB signaling pathways.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.40-45
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• 1992

Acidic nucleotidase from Asfiergilius nlger has been partially purified by Sepharose CL-6B gel filtration and DEAE-Sephacel ion exchange chromatography. The optimum pH and temperature for the enzyme reaction with 5'-AMP or 3'-AMP as a substrate were 4.5 and 55%, respectively. However, the optimum temperature became 70% when p-nitrophenyl phosphate was used as a substrate. The enzyme was stable at acidic pH. The enzyme activity was not affected by addition of various nucleotides, nucleosides and inorganic phosphates. Ferric, aluminium, vanadate and molybdate ions inhibited the enzyme activity dramatically. In kinetic studies, $K_m$), values for 3'-AMP, 5'-AMP and p-nitrophenyl phosphate were 1.39 mM, 1.5 mM and 5.77 mM, respectively. The substrate efficiency ($V_{max}/K_m$) shows 3'-AMP is the prefered substrate for the enzyme among tested substrates.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.153-158
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• 1998

Effects of cyclic (c) AMP and G-protein related reagents (3-isobutyl-l-methyxanthine (IBMX), Forskolin (FSK), cholera toxin (CTX), and pertussis toxin (PTX≫ on estradiol-17$\beta$ induced vitellogenin (VTG) induction were examined in primary hepatocyte cultures in rainbow trout Oncorhynchus mykiss. The addition of IBMX, FSK, or CTX to the incubation medium markedly increased VTG production, while PTX was not effective in stimulating the production. It is well known that cAMP regulates phosphorylation and dephosphorylation through mediation of protein kinase A. These results suggest that VTG production is highly dependent on cAMP state in hepatocytes because of its highly phosphorylated nature.

• Animal cells and systems
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• v.3 no.2
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• pp.207-213
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• 1999

During the differentiation of Naegleria gruberi amoebas into flagellates, the amoebas undergo sequential changes in cell shape and form new cellular organelles. To understand the nature of the signal which initiates this differentiation and the signal transduction pathway, we treated cells with four agents, PMA, retinoic acid (RA), okadaic acid, and cAMP. Retinoic acid and cAMP had specific effects on the differentiation of N. gruberi depending on the time of the drug treatment. Addition of (100$\mu$M) retinoic acid at the initiation of differentiation inhibited differentiation by blockinq the transcription of differentiation specific genes (e.g., $\beta$-tubulin). This inhibition of differentiation by retinoic acid was overcome by co-treatment with cAMP (or dbcAMP, 20 $\mu$M). Addition of retinoic acid at later stages (30 and 70 min) had no effect on the transcriptional regulation of the $\beta$-tubulin gene, however the differentiation was inhibited by different degrees. Co-treatment of cAMP at these stages did not overcome the inhibitory effect of retinoic acid. These results suggest that the role of retinoic acid as a transcriptional regulator might be conserved throughout the evolution of eukaryotes.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.221-226
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• 2023

Proper activation and aggregation of platelets are necessary, but excessive or abnormal aggregation can lead to cardiovascular diseases such as stroke, thrombosis, and atherosclerosis. Therefore, identifying a substance that can regulate or inhibit platelet aggregation is important for preventing and treating these diseases. Several studies have shown that certain ginsenoside compounds in Panax ginseng can inhibit platelet aggregation. Among these compounds, Rk3 (G-Rk3) from Panax ginseng needs to be further explored in order to reveal the mechanisms of action during inhibition. G-Rk3 significantly increased amounts of cyclic adenosine monophosphate (cAMP) and led to significant phosphorylation of cAMP-dependent kinase substrates vasodilator-stimulated phosphoprotein and inositol 1,4,5-trisphosphate receptor. Furthermore, the effect of G-Rk3 extended to the inhibition of PI3K/Akt phosphorylation resulting in the reduced secretion of intracellular granules. Ultimately, G-Rk3 effectively inhibited platelet aggregation. Therefore, we suggest G-Rk3's potential as a prophylactic or therapeutic agent for cardiovascular diseases caused by faulty platelet aggregation.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.539-546
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• 2007

Increasing emission of $CO_2$ significantly effects the global warming. Chemical absorption is one of separation methods of $CO_2$ from the industrial flue gases. In this study, the $CO_2$ removal efficiency as well as the $CO_2$ absorption amount of aqueous AMP (2-amino-2-methyl-1-propanol) solutions were measured using the continuous absorption and regeneration apparatus. We investigated the effect of aqueous AMP+AEPD(2-amino-2-ethyl-1, 3-propanediol) and AMP+TIPA (triisopropanolamine) solutions to enhance absorption characteristics of AMP. As a result of this study, the absorption amount and $CO_2$ removal efficiency were increased with adding TIPA into 30 wt.% AMP. The absorption amount and $CO_2$ removal efficiency of aqueous 30 wt.% AMP+5 wt.% TIPA solution were $1.70\;kg-CO_2/kg-absorbent$ and 91.1%, while those of aqueous 30 wt.% AMP solution were $1.58\;kg-CO_2/kg-absorbent$ and 89.3%. In addition, aqueous 30 wt.% AMP+5 wt.% TIPA solution used in the study revealed the high stripping efficiency, which was almost 98%, at the temperature of $110^{\circ}C$. Thus, the temperature of regenerator should be operated at $110^{\circ}C$.

• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.254-260
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• 1994

Magnaporthe grisea, a causal agent of blast, forms a specialized infection structure, an appressorium, to infect host. Hydrophobicity of contact surface and cAMP have been suggested as a primary environmental signal and a second messenger to trigger and mediate appressorium formation in this fungus, respectively. To generalize these factors in field isolates of M. girsea, twenty isolates originated from rice and other gramineous hosts were tested. Seventeen including rice and non-rice isolates formed appressoria on hydrophobic surface, but none of isolates formed appressoria on hydrophilic surface. Eighteen isolates formed appressoria on hydrophilic surface in the presence of IBMX, an inhibitor of phosphodiesterase, except two rice isolates. These results strongly support the hypothesis that appressorium formation by M. grisea is induced by hydrophobic hard surface and regulated by the endogenous level of cAMP in the cells. Understanding fungal development is not only of biological interest but provides new targets for novel disease control strategies.

• Microbiology and Biotechnology Letters
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• v.51 no.3
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• pp.309-313
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• 2023

Here we report essential features of the draft genome of an AmpC-β-lactamase-producing bacterial isolate obtained from farm tomatoes in South Africa. The isolate designated strain Tom1 featured a genome of 4950426 bp with a G+C% of 59.83. It was identified as Serratia marcescens by ribosomal multilocus sequence typing (rMLST), digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI), and phylogenetic analysis using reference genomes. Its genome encoded an AmpC-β-lactamase (bla_SST-1), an efflux pump providing tetracycline resistance (tet(41)), and an aminoglycoside acetyltransferase (aac(6')-Ic). Additionally, genes encoding proteins involved in prodigiosin biosynthesis and associated with adherence, biofilm formation, virulence, and pathogenicity were detected.