Optimization of a cucurbit6uril-based real-time label-free method for analyzing the activity of ornithine decarboxylase / 生物工程学报

Ornithine decarboxylase (ODC) is a key enzyme in the biosynthetic pathway of polyamines and catalyzes the decarboxylation of ornithine to produce putrescine. Inhibition of ODC activity is a potential approach for the prevention and treatment of many diseases including cancer, as the expression levels and the activities of ODC in many abnormal cells and tumor cells are generally higher than those of normal cells. The discovery and evaluation of ODC inhibitors rely on the monitoring of the reaction processes catalyzed by ODC. There are several commonly used methods for analyzing the activity of ODC, such as measuring the yield of putrescine by high performance liquid chromatography, or quantifying the yield of isotope labelled carbon dioxide. However, the cumbersome operation and cost of these assays, as well as the difficulty to achieve high-throughput and real-time detection, hampered their applications. In this work, we optimized a real-time label-free method for analyzing the activity of ODC based on the macromolecule cucurbit[6]uril (CB6) and a fluorescent dye, DSMI (trans-4-[4-(dimethylamino) styryl]-1-methylpyridinium iodide). Finally, the optimized method was used to determine the activities of different ODC inhibitors with different inhibition mechanisms.

Exogenous spermidine ameliorates tubular necrosis during cisplatin nephrotoxicity / 대한해부학회지

The hallmark of cisplatin-induced acute kidney injury is the necrotic cell death in the kidney proximal tubules. However, an effective approach to limit cisplatin nephrotoxicity remains unknown. Spermidine is a polyamine that protects against oxidative stress and necrosis in aged yeasts, and the present study found that exogenous spermidine markedly attenuated tubular necrosis and kidney dysfunction, but not apoptosis, during cisplatin nephrotoxicity. In addition, exogenous spermidine potently inhibited oxidative/nitrative DNA damage, poly(ADP-ribose) polymerase 1 (PARP1) activation and ATP depletion after cisplatin injection. Conversely, inhibition of ornithine decarboxylase (ODC) via siRNA transfection in vivo significantly increased DNA damage, PARP1 activation and ATP depletion, resulting in acceleration of tubular necrosis and kidney dysfunction. Finally, exogenous spermidine removed severe cisplatin injury induced by ODC inhibition. In conclusion, these data suggest that spermidine protects kidneys against cisplatin injury through DNA damage and tubular necrosis, and this finding provides a novel target to prevent acute kidney injury including nephrotoxicity.

Characterization of OAZ1 and its potential functions in goose follicular development

Background: Ornithine decarboxylase antizyme 1 (OAZ1) is an important regulator of polyamine synthesis and uptake. Our previous studies indicated that high OAZ1 expression in the ovaries of laying geese is responsible for poor egg production. In the present study, the molecular characterization of goose OAZ1 gene was analyzed, as well as the expression profile in various follicular tissues. Results: An 873-bp cDNA sequence of the OAZ1 gene (Accession No. KC845302) with a +1 frameshift site (+175T) was obtained. The sequence consisted of a 652-bp two overlapping open reading frames (a putative protein with 216 amino acids). The OAZ domain, OAZ signature and OAZ super family domain were prominent conserved regions among species. As the follicle size increased, OAZ1 abundance showed an increasing trend during follicular development, while it decreased during follicular regression. The level of OAZ1 mRNA expression was the lowest in the fifth largest preovulatory follicle, and was 0.65-fold compared to the small white follicle (P b 0.05). OAZ1 mRNA expression in the largest preovulatory and postovulatory follicle was 2.11- and 2.49-fold compared to the small white follicle, respectively (P b 0.05). Conclusions: The goose OAZ1 structure confirms that OAZ1 plays an important role in ornithine decarboxylase-mediated regulation of polyamine homeostasis. Our findings provide an evidence for a potential function of OAZ1 in follicular development, ovulation and regression.

Spermidine is protective against kidney ischemia and reperfusion injury through inhibiting DNA nitration and PARP1 activation / 대한해부학회지

Kidney ischemia and reperfusion injury (IRI) is associated with a high mortality rate, which is attributed to tubular oxidative and nitrative stresses; however, an effective approach to limit IRI remains elusive. Spermidine, a naturally occurring polyamine, protects yeast cells against aging through the inhibition of oxidative stress and necrosis. In the present study, spermidine supplementation markedly attenuated histological damage and kidney dysfunction during IRI. In addition, exogenous spermidine potently inhibited poly(ADP-ribose) polymerase 1 (PARP1) activation and DNA nitrative/oxidative stress following IRI. Conversely, inhibition of ornithine decarboxylase (ODC) via siRNA transfection in vivo significantly enhanced DNA nitration, PARP1 activation, and functional damage during IRI. Finally, in ODC knockdown kidneys, PARP1 inhibition attenuated histological and functional damage induced by IRI, but not DNA nitrative stress. In conclusion, these data suggest that spermidine protects kidneys against IRI through blocking DNA nitration and PARP1 activation and this finding provides a novel target for prevention of acute kidney injury including IRI.

Quinolone resistance and ornithine decarboxylation activity in lactose-negative Escherichia coli

Quinolones and fluoroquinolones are widely used to treat uropathogenic Escherichia coli infections. Bacterial resistance to these antimicrobials primarily involves mutations in gyrA and parC genes. To date, no studies have examined the potential relationship between biochemical characteristics and quinolone resistance in uropathogenic E. coli strains. The present work analyzed the quinolone sensitivity and biochemical activities of fifty-eight lactose-negative uropathogenic E. coli strains. A high percentage of the isolates (48.3%) was found to be resistant to at least one of the tested quinolones, and DNA sequencing revealed quinolone resistant determining region gyrA and parC mutations in the multi-resistant isolates. Statistical analyses suggested that the lack of ornithine decarboxylase (ODC) activity is correlated with quinolone resistance. Despite the low number of isolates examined, this is the first study correlating these characteristics in lactose-negative E. coli isolates.

Hydroxydibenzoylmethane induces apoptosis through repressing ornithine decarboxylase in human promyelocytic leukemia HL-60 cells

Ornithine decarboxylase (ODC) is the rate-limiting enzyme in polyamine biosynthesis and a target for chemoprevention. Hydroxydibenzoylmethane (HDB), a derivative of dibenzoylmethane of licorice, is a promising chemopreventive agent. In this paper, we investigated whether HDB would inhibit the ODC pathway to enhance apoptosis in human promyelocytic leukemia HL-60 cells. We found ODC enzyme activity was reduced during HDB treatment. Overexpression of ODC in HL-60 parental cells could reduce HDB-induced apoptosis, which leads to loss of mitochondrial membrane potential (Deltapsim), through lessening intracellular ROS. Furthermore, ODC overexpression protected cytochrome c release and the activation of caspase-3 following HDB treatment. The results demonstrated HDB-induced apoptosis was through a mechanism of down-regulation of ODC and occurred along a ROS-dependent mitochondria-mediated pathway.

Effect of alfa-difluormethylornithine on Anastrepha fraterculus (Diptera, Tephritidae) ovary size / Efeito da alfa-difluorometilornitina nas dimensões dos ovários em Anastrepha fraterculus (Diptera, Tephritidae)

Ovarian sizes (length and width) were measured in young females of Anastrepha fraterculus (Wiedemann) (Diptera, Tephritidae) subjected or not to the inhibitor α -difluormethylornithine (α -DFMO). The most effective concentration of α -DMFO used was 50 mM and the ovarian measurements (length and width) of the treated females were smaller than those of females not treated with α -DMFO. These data may suggest some relationship between ornithine decarboxylase (ODC) and sexual maturation in A. fraterculus.

As dimensões dos ovários (comprimento e largura) foram mensuradas em fêmeas jovens da Anastrepha fraterculus (Wiedemann) (Diptera, Tephritidae) submetidas ou não ao inibidor α -difluormetilornitina (α -DFMO). A concentração mais efetiva de α -DMFO utilizada foi 50 mM e as medidas (comprimento e largura) das fêmeas tratadas com o inibidor foram menores que as fêmeas não tratadas com inibidor α -DMFO. Estes dados podem sugerir uma relação entre ornitina descarboxilase (ODC) e maturação sexual em A. fraterculus.

A Case of Haemophilus parainfluenzae Endocarditis / 대한임상미생물학회지

The HACEK group of bacteria (Haemophilus parainfluenzae, H. aphrophilus, H. paraphrophilus, Actinobacilus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corodens, and Kingella kingae) are the normal flora of the upper respiratory tract and oropharynx. The organisms infect abnormal cardiac valves, causing subacute native endocarditis or prosthetic valve endocarditis more than one year after valve surgery. Haemophilus species are responsible for only 0.5~1% of all infective endocarditis cases. Embolization occurs in 60% and the mortality rate ranges from 16~45% of cases of infective endocarditis caused by H. parainfluenzae. We experienced a case of infective endocarditis due to H. parainfluenzae in a 37-year-old male admitted with high fever, chills, nausea & vomiting, chest discomfort, and blurred vision. The organism was isolated from a blood culture and was identified as H. parainfluenzae by factor V requirement, negativity at urea, positivity at ornithine decarboxylase, and acid production from glucose and maltose. The patient was treated with antibiotics and symptoms and signs were improved

Inhibitory effects of ODC and AdoMetDC bi-antisense virus on the growth and invasion of lung cancer cell A-549 / 中华外科杂志

<p><b>OBJECTIVE</b>To study the inhibitory effects of antisense bicistronic recombinant adenovirus vector of ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (Ad-ODC-AdoMetDCas) on polyamine biosynthesis,proliferation and invasion of lung cancer cells.</p><p><b>METHODS</b>Adenovirus-mediated gene transduction efficiency was assessed with counting GFP-positive cells using trypan blue. Western Blot and HPLC were used to detect ODC and S-AdoMetDC expression and polyamine content in A-549 cells respectively. Viable cell counting and cell cycle analysis were adopted to evaluate cell growth and cell cycle distribution, and A-549 cell invasion in vitro was detected with Matrigel invasion assay.</p><p><b>RESULTS</b>Approximate 75% of A-549 cells were infected with Ad-ODC-AdoMetDCas when multiplicity of infection reached 50. Our study demonstrated that Ad-ODC-AdoMetDCas vector-mediated gene transfer inhibited tumor cell growth through the blockade of polyamine synthesis pathway. The tumor cells were arrested at cell cycle G1 phase after gene transfer. Gene transferred tumor cells were shown to possess markedly decreased invasiveness.</p><p><b>CONCLUSION</b>Ad-ODC-AdoMetDCas has significant inhibitory effects on lung cancer cell proliferation and invasion and bears therapeutic potential for the treatment of lung cancer.</p>

Intracellular polyamine pools, oligopeptide-binding protein A expression, and resistance to aminoglycosides in Escherichia coli

The role of intracellular free polyamine (putrescine and spermidine) pools in multiple resistance to aminoglycoside antibiotics was investigated among in vitro selected kanamycin-resistant Escherichia coli J53 mutants expressing diminished oligopeptide-binding protein (OppA) levels and/or defective ornithine decarboxylase (ODC) activity. The results suggest that diminished OppA content, but not defective ODC activity expression, increased the relative concentration of free spermidine as compared to the wild type strain. Moreover, by adding exogenous polyamines or polyamine synthesis inhibitors to cultures with different mutant strains, a direct relationship between the intracellular OppA levels and resistance to kanamycin was revealed. Collectively these results further suggest a complex relation among OppA expression, aminoglycoside resistance and polyamine metabolism.

Effect of alpha-difluoromethylornithine on the expression of ODC mRNA in the cortex and hippocampus in rats after cerebral ischemia reperfusion / 中南大学学报(医学版)

OBJECTIVE@#To explore the mechanism of alpha-difluoromethylornithine (DFMO) inhibiting ODC activity in the cortex and hippocampus in rats.@*METHODS@#Forty male rats was randomly divided into ischemal control group and DFMO pretreatment group. DFMO was given intravenously half an hour before global cerebral ischemia, and expression of ODC mRNA was measured by comparative reverse transcription-polymerase chain reaction (RT-PCR) in the cortex and hippocampus in rats after 2, 4, 6 h and 8 h of reperfusion. The variations of the expression of ODC mRNA were studied in the DFMO pretreatment group and the ischemal control group respectively.@*RESULTS@#After 2, 4 and 6 h of reperfusion, the expression of ODC mRNA in the cortex and hippocampus in the pretreatment group was lower than that in the ischemia control group significantly (P 0.05).@*CONCLUSION@#DFMO suppressed the expression of ODC mRNA after different lengths of reperfusion following 10-minute global cerebral ischemia in rats and it may be one of the ways for DFMO to inhibit ODC activity.

Effects of power frequency magnetic field on gap junction intercellular communication of astrocytes / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>In order to explore if power frequency magnetic field (PFMF) can act as cancer promoter or be synergistic with phorbol 12-myristate 13-acetate (TPA) in cancer promotion, the effects of 50 Hz MF on gap junction intercellular communication (GJIC) of astrocytes were observed.</p><p><b>METHODS</b>Fluorescence redistribution after photobleaching (FRAP) was adopted to observe the recovery of fluorescence intensity in the bleached cells thus to estimate intercellular communication by gap junction. Comparative fluorescence intensity recovery rate (CFIRR) was as evaluation index. The effects of 50 Hz MF alone or with TPA on GJIC of astrocytes were studied.</p><p><b>RESULTS</b>After 3 ng/ml TPA treatment for 1 hour, M(d) of CFIRR was 4.53%/min, whereas that in the control group was 9.74%/min (H = 12.084, P < 0.005). After exposure to 0.8 and 1.6 mT magnetic field for 24 hours respectively, M(d) of CFIRR was 8.25%/min and 6.68%/min respectively, no significant difference from that of control (H = 32.617, P > 0.05). After exposure to 0.8 and 1.6 mT magnetic field for 23 hours then combined with 3 ng/ml TPA treatment for 1 hour, M(d) of CFIRR was 3.32%/min and 2.85%/min respectively, also no significant difference from that in the group treated with 3 ng/ml TPA alone (H = 2.589, P > 0.05).</p><p><b>CONCLUSION</b>50 Hz MF (within 0 - 1.6 mT) alone could not inhibit GJIC of astrocytes; with TPA, could not enhance the inhibition of TPA on GJIC of astrocytes. But with MF intensity increasing, the inhibition of MF on GJIC showed elevated tendency.</p>

Effect of diethylstilbestrol on polyamine metabolism in hamster epididymis / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis.</p><p><b>METHODS</b>Male golden hamsters of 7-week-old were kept under a light and dark cycle of 14 h and 10 h for 1 week to stimulate maximally the gonadal function. DES was injected subcutaneously at doses of 0.01 mg . kg(-1) . day(-1), 0.1 mg . kg(-1) . day(-1) and 1 mg . kg(-1) . day(-1) for one week.</p><p><b>RESULTS</b>DES treatment caused a significant decrease in the weight of epididymis. The activity of epididymal ornithine decarboxylase (ODC) increased 1 day after DES treatment, kept at a high level for 4 days and then decreased to nearly normal level at day 7. The activity of spermidine/spermine N1-acetyltransferase (SSAT) also increased transiently after DES treatment. The contents of putrescine, spermidine, spermine and N(1)-acetylspermidine were increased 1 day approximately 4 days after DES treatment and restored to normal at day 7. All these changes showed a marked difference between the caput and the cauda.</p><p><b>CONCLUSION</b>The polyamine biosynthesis in the hamster epididymis can be affected by DES, a xenoestrogen. DES may probably affect polyamine metabolism in the epididymis by regulating the rate-limiting enzymes involved in the polyamine biosynthesis.</p>

Melatonin reduces ultraviolet-B induced cell damages and polyamine levels in human skin fibroblasts in culture

UV radiation is known to cause photoaging of the skin and is considered one of the leading cause of developing skin carcinogenesis. Melatonin which has a highly lipophilic molecular structure facilitating penetration of cell membranes and serving as an extra- and intracellular free radical scavenger has been demonstrated to protect photodamage of skin affected by UV exposure. In this study, we have examined the role of melatonin in response to UVB induced photodamaging process, using human skin fibroblasts in vitro. Cell survival curves after UVB irradiation showed dose-dependent decrease. Only 60% of fibroblasts were survived at 140 mJ/cm2 UVB irradiation. By pre-cultivation of cells with melatonin (100 nM), a significant number of cells remained unaffected. After UVB irradiation with 70 mJ/cm2, the level of putrescine was 1.7+/-0.3 fold increased compared to melatonin pre-treated group. In Northern analyses, the transcriptional level of ornithine decarboxylase (ODC) gene expression was increased by UVB irradiation and prohibited by melatonin. These results indicated that melatonin was effectively able to neutralize membrane peroxidation when present in relevant concentration during UVB irradiation and diminishes the UVB-induced increase of polyamine synthesis and ODC gene expression. Collectively, ODC response to UVB induced changes are possibly involves a melatonin or antioxidant sensitive regulatory pathway in normal human skin fibroblast.

The effects of constant and alternating temperatures on the reproductive potential, life span, and life expectancy of Anastrepha fraterculus (Wiedemann) (Dipteria: Tephritidae)

Ovarian development, oviposition, larval eclosion, ornithine decarboxylase (ODC) activity, ovarian, testis and ejaculatory apodeme measurements (length, width, and area), and the number of spermatozoa of Anastrepha fraterculus (Wiedemann) were analyzed at alternating (20º/6ºC and 20º/13°C) and constant (6°C; 25°C) temperatures. Life span and life expectancy were also analyzed for both genders. All the results suggest that temperature, especially alternating temperatures, increase not only male and female reproductive potential but also their life span and life expectancy. These changes can be a powerful strategy triggered by A. fraterculus as a means to survive the stressful temperature conditions found in winter in the apple production region in Brazil, enabling this species to increase its population density and cause apple damage when spring begins

Changes in free polyamines and related enzymes during stipule and pod wall development in Pisum sativum.

Level of free polyamines, their key metabolic enzymes, and other features related to ageing were examined during stipule and pod wall development in pea (Pisum sativum). Free polyamine titre (per unit fresh mass) in both the organs, the specific activities of arginine decarboxylase and ornithine decarboxylase in the pod wall, gradually decreased with maturation. In stipule, these enzymes attained peak activity at 15 days after pod emergence and declined thereafter. Ornithine decarboxylase activity was greater in pod wall than in stipule; while, arginine decarboxylase activity was higher in stipule. Activity of degradative enzyme diamine oxidase increased with the onset of senescence in both the organs. Chlorophyll and electrical conductance had a inverse relationship throughout the experimental period, whereas, the chlorophyll content was directly related with polyamine levels in both stipule and pod wall during aging. On the other hand, protein and RNA contents were positively correlated with free polyamines throughout the test period in stipule, but in the pod wall this was true only for the later stages of development.

Effect of Astragalus injection in promoting IEC-6 cell differentiation through activating ornithine decarboxylase / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the mechanism of Astragalus injection (AI) in repairing mucous membrane by observing its effects on the proliferation, differentiation, migration as well as on intracellular content of ornithine decarboxylase (ODC) and polyamine in rat's small intestinal crypt-like cell line (IEC-6) in vitro.</p><p><b>METHODS</b>AI was added in the IEC-6 cells after they had been cultured for 24 hours. Twelve hours after adding AI, the cells were collected to test the ODC mRNA level, ODC protein, ODC activity and the intracellular content of putrescine. Twenty-four hours after adding AI, the condition of cell proliferation and differentiation was observed. Another group of IEC-6 cells were injured after being cultured for 72 hours, and AI was added, the cell migration was observed at 24 hours, 48 hours and 72 hours after medication.</p><p><b>RESULTS</b>AI could inhibit IEC-6 cell proliferation, promote the cell differentiation, but with no apparent effect on injured IEC-6 cell migratin. AI of 62.5-250 micrograms/ml concentration could increase the ODC mRNA level, as compared with control, the difference was significant (P < 0.05-0.01). ODC activity and intracellular content of putrescine could be gradually increased by AI in a dose-dependant manner. No effect of AI was shown on ODC protein in various dosage of AI groups.</p><p><b>CONCLUSION</b>AI could promote IEC-6 cell differentiation by means of inducing the ODC activity and biosynthesis of polyamine, but without significant effect on cell migration.</p>

Virulence Factors and Genotyping of Shigella sonnei Isolated from Patients / 대한진단검사의학회지

BACKGROUND: Nineteen strains of Shigella sonnei isolated from the patients were examined regarding their biochemical characterization, serotype, and antibiotics resistance, and then analyzed for plasmid DNA profile. METHODS: Strains were tested for possession of set1A, set1B, sen, ipaH, ial, stx and invE genes using the polymerase chain reaction (PCR) method and were analyzed using the pulsed-field gel electrophoresis (PFGE) pattern against 7 outbreak isolates (10 strains). RESULTS: These strains had the typical biochemical characterization of S. sonnei with positive ornithine decarboxylase and -galactosidase activity, but were negative in mannitol fermentation. Serotype were identified as the I phase in 13 strains (68.0%) and the II phase in 6 strains (32.0%). All strains were resistant to erythromycin, vancomycin, tetracycline, and penicillin. The antibiogram type showed 4 groups from I to IV. The strains showed 8 types of plasmid profiles and were designated as P1 to P8. By the PCR, the ipaH gene and the set1B gene were detected from all of the 16 strains. The invE was detected from 9 strains (56.3%), and the sen gene was detected from 5 strains. All strains were negative for the Stx and the set1A gene. High-molecular-weight genomic DNA was prepared from 7 outbreak isolates (10 strains) and digested with the restriction endonuclease XbaI. Restriction fragment patterns of chromosomal DNA were demonstrated by PFGE. XbaI produced about 23 fragments in all strains with the their size ranged from 40 to 680 kb. Ten strains could be differentiated to 3 patterns by chromosomal DNA fingerprint. CONCLUSIONS: All of the Shigella sonnei strains that were isolated from Busan Province showed similar chromosomal DNA fragment patterns, while the Japanese differed in chromosomal DNA fingerprint pattern. PFGE is useful for the epidemiological study of Shigella sonnei associated endemic diarrhea.

Effects of alpha-difluoromethylornithine on the Fas expression and apoptosis in Hep-2 cells

DFMO is an irreversible inhibitor of ornithine decarboxilase (ODC), the key enzyme in mammalian polyamine biosynthesis, and has been shown to induce apoptosis. In this paper, the relation between the effects of DFMO on the polyamine content, apoptotic index and Fas expression in HEP-2 cells was determined. Fas is a type I membrane protein with a molecular mass of 45 kDa, which mediates apoptosis. The results suggest that the treatment with the polyamine inhibitor DFMO induced the expression of the surface antigen Fas, which could be responsible for trigger apoptosis in these cells.