A simple method for normalization of DNA extraction to improve the quantitative detection of soil-borne plant pathogenic oomycetes by real-time PCR.

UNLABELLED: Most of the current research into the quantification of soil-borne pathogenic oomycetes lacks determination of DNA extraction efficiency, probably leading to an incorrect estimation of DNA quantity. In this study, we developed a convenient method by using a 100 bp artificially synthesized DNA sequence derived from the mitochondrion NADH dehydrogenase subunit 2 gene of Thunnus thynnus as a control to determine the DNA extraction efficiency. The control DNA was added to soils and then co-extracted along with soil genomic DNA. DNA extraction efficiency was determined by the control DNA. Two different DNA extraction methods were compared and evaluated using different types of soils, and the commercial kit was proved to give more consistent results. We used the control DNA combined with real-time PCR to quantify the oomycete DNAs from 12 naturally infested soils. Detectable target DNA concentrations were three to five times higher after normalization. Our tests also showed that the extraction efficiencies varied on a sample-to-sample basis and were <50%. Therefore, the method introduced here is simple and useful for the accurate quantification of soil-borne pathogenic oomycetes. SIGNIFICANCE AND IMPACT OF THE STUDY: Oomycetes include many important plant pathogens. Accurate quantification of these pathogens is essential in the management of diseases. This study reports an easy method utilizing an external DNA control for the normalization of DNA extraction by real-time PCR. By combining two different efficient soil DNA extraction methods, the developed quantification method dramatically improved the results. This study also proves that the developed normalization method is necessary and useful for the accurate quantification of soil-borne plant pathogenic oomycetes.

Development of loop-mediated isothermal amplification assay for the detection of Pythium myriotylum.

UNLABELLED: This study reports the development of a loop-mediated isothermal amplification (LAMP) reaction for the detection of Pythium myriotylum. The primer set targeting the ITS sequence of P. myriotylum worked most efficiently at 60°C and allowed the detection of P. myriotylum DNA within 30 min by fluorescence monitoring using a real-time PCR instrument. The peak denaturing temperature of amplified DNA was about 87·0°C. In specificity tests using eight Pythium myriotylum strains, 59 strains from 39 species of Pythium, 11 Phytophthora strains and eight other soil-borne pathogens, LAMP gave no cross-reactions. The detection limit was 100 fg of genomic DNA, which was as sensitive as PCR. LAMP could detect P. myriotylum in hydroponic solution samples, and the results coincided with those of the conventional plating method in almost all cases. The LAMP method established in this study is a simple and sensitive tool for the detection of P. myriotylum. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows the first LAMP assay for the detection of Pythium myriotylum. The primer set designed from ITS region of P. myriotylum can detect the pathogen in field sample with a fast and convenient method. Analysis of the annealing curve of the LAMP reaction products increases the reliability of the LAMP diagnosis. This study shows that the diagnostic method using the LAMP assay is useful for monitoring P. myriotylum in the field.

Association of left atrial phasic volumes with systemic arterial stiffness and ankle-brachial index in hypertensive patients.

Left atrial (LA) phasic volumes consist of reservoir, conduit and booster pump volumes. Arterial stiffness is linked to lower systemic arterial compliance (SAC) contributing to cardiac afterload. Arterial stiffness may be a modulator of LA phasic volumes. Echocardiography was performed in 161 hypertensive patients and in 50 normotensive subjects in order to assess biplane LA volumes (maximum, before atrial contraction, minimum), early and late diastolic mitral annular velocity (e' and a'), and LV stroke volume. LA emptying volumes (total, passive, active) were calculated from these LA volumes. Blood pressures were measured using an automated oscillometric device simultaneously at the four limbs for evaluating pulse pressure (PP) and ankle-brachial index (ABI). SAC was estimated by the ratio of LV stroke volume indexed by body surface area (BSA) divided by PP. All three LA volumes, LA total volume and LA active emptying volume were greater in hypertensive patients than in normotensive subjects. A multiple linear regression analysis indicated that LA passive emptying volume (reservoir=early diastole)/BSA correlated positively with ABI after being adjusted for age, gender, BSA, LV mass, max LA volume, e' and SAC in hypertensive patients. LA active emptying volume (booster=late diastole)/BSA correlated positively with SAC after being adjusted for age, gender, BSA, LV mass, LA volume before atrial contraction, a' and ABI. LA reservoir volume was associated with ABI, and LA booster volume was related to systemic arterial stiffness in hypertensive patients, suggesting the LA-arterial coupling in this clinical setting.

Determination of three enolase isozymes and S-100 protein in various tumors in children.

Three enolase isozymes (alpha alpha, alpha gamma, and gamma gamma) and S-100 protein in the extract of neuroendocrine tumors (neuroblastoma, ganglioneuroblastoma, ganglioneuroma, and pheochromocytoma) and nonneuroendocrine tumors (Wilms' tumor, rhabdomyosarcoma, and hepatoblastoma) were determined by means of enzyme immunoassay systems. All of the tumors examined showed a high level of alpha alpha-enolase (1.71 to 19.0 micrograms/mg protein). Levels of nervous system-specific enolases (NSE; alpha gamma and gamma gamma) in the neuroendocrine tumors were also rather high (alpha gamma, 1.64 to 7.45 micrograms/mg protein; gamma gamma, 0.052 to 5.56 micrograms/mg protein). However, the NSE concentration in the extract of nonneuroendocrine tumors was low (alpha gamma, less than 0.88 micrograms/mg protein; gamma gamma, 0 microgram/mg protein). The level of S-100 protein was relatively high in ganglioneuroma (greater than 500 ng/mg protein) and ganglioneuroblastoma (greater than 100 ng/mg protein), but low in neuroblastoma (less differentiated neuroendocrine tumor) and nonneuroendocrine tumors. Serum levels of enolase isozymes were also determined in neuroblastoma patients before and after resection of primary tumor or effective chemotherapy. The elevated level of serum NSE (alpha gamma and gamma gamma) was markedly decreased with little change in the alpha alpha level by the treatment.

Production of the alpha subunit of guanine nucleotide-binding protein GO by neuroendocrine tumors.

We have found that neuroendocrine tumors (including neuroblastoma, ganglioneuroma, gut carcinoid, pheochromocytoma, medullary thyroid carcinoma, insulinoma, glucagonoma, prolactinoma, carotid body tumor, and small cell lung carcinoma) produce considerable amounts (about 1000-80,000 ng/g tissue) of the alpha subunit of guanine nucleotide-binding protein, GO (GO alpha), whereas nonneuroendocrine tumors contain less than 300 ng of GO alpha/g tissue. GO alpha in the neuroendocrine tumors was present both in the soluble fraction, and cholate-extractable membrane-bound fraction of tissues. Immunoblots of membrane fractions of neuroblastoma and carcinoid tissues confirmed that the immunoreactive substance in the tumor tissues was GO alpha. Immunohistochemically, GO alpha was localized consistently in the cell membrane and occasionally in the cytoplasm of neuroendocrine tumors. GO alpha was also detected in sera of 73% patients with neuroblastoma at diagnosis, whereas serum GO alpha concentrations in control children, or patients with nonneuroendocrine tumors were lower than the detection limit of the immunoassay method employed. Serum GO alpha concentrations in patients with neuroblastoma changed with the clinical course; they fell in patients responding to treatment and increased in patients who relapsed. Since GO alpha, a specific protein in the neural and neuroendocrine cells, was found to be produced in considerable amounts by all types of neuroendocrine tumors but not in nonneuroendocrine tumors, GO alpha might be a useful biomarker for neuroendocrine tumors.

The alpha subunit of GTP-binding protein G0 in neuroblastoma: correlation with advanced disease stage.

Tissue levels of the alpha subunit of G protein G0 (G0 alpha) were measured in solid tumors from pediatric patients by immunoassay. G0 alpha concentrations were determined in the supernatant obtained by centrifugation of tissue homogenates prepared in the presence (total G0 alpha) or absence of 2% sodium cholate (soluble G0 alpha). Mean G0 alpha concentrations (total G0 alpha and soluble G0 alpha) in neuroblastomas (7 ganglioneuromas, 13 ganglioneuroblastomas, and 50 neuroblastomas) were over 50-fold higher than those in other solid tumors from pediatric patients (n = 13). Mean total G0 alpha and soluble G0 alpha concentrations were 207.0 +/- 166.0 (SD) ng/mg of cholate-extractable protein and 58.6 +/- 47.0 ng/mg of soluble protein, respectively, in the neuroblastoma group (n = 70). Total G0 alpha concentration decreased with disease stage and was strongly correlated with outcome in patients with neuroblastoma. The mean total G0 alpha concentration in tumors from younger patients (< 1 year old) was 297.0 +/- 137.0 ng/mg of cholate-extractable protein, significantly higher than in tumors from older patients (140.0 +/- 155.0 ng/mg cholate-extractable protein, P < 0.0001). These results suggest that total G0 alpha levels in neuroblastoma may indicate the degree of malignancy.

Biological and biochemical properties of Ret with kinase domain mutations identified in multiple endocrine neoplasia type 2B and familial medullary thyroid carcinoma.

Several mutations were identified in the kinase domain of the RET proto-oncogene in patients with multiple endocrine neoplasia (MEN) 2B, familial medullary thyroid carcinoma (FMTC) or sporadic medullary thyroid carcinoma. We introduced seven mutations (glutamic acid 768-->aspartic acid (E768D), valine 804-->leucine (V804L), alanine 883-->phenylalanine (A883F), serine 891-->alanine (S891A), methionine 918-->threonine (M918T), alanine 919-->proline (A919P) and E768D/A919P) into the short and long isoforms of RET cDNA and transfected the mutant cDNAs into NIH3T3 cells. The transforming activity of the long isoform of Ret with each mutation was much higher that that of its short isoform. Based on the levels of the transforming activity, these mutant RET genes were classified into two groups; a group with high transforming activity (A883F, M918T and E768D/A919P) and a group with low transforming activity (E768D, V804L, S891A and A919P) (designated high group and low group). Interestingly, the level of transforming activity correlated with clinical phenotypes; high group Ret with the A883F or M918T mutation and low group Ret with the E768D, V804L or S891A mutation were associated with the development of MEN 2B and FMTC, respectively. In addition, we found that substitution of phenylalanine for tyrosine 905 present in the kinase domain abolished both transforming and autophosphorylation activities of low group Ret whereas it did not affect the activities of high group Ret.

Enzymatic properties of endo-beta-N-acetylglucosaminidases from developing tomato fruits and soybean seeds: substrate specificity of plant origin endoglycosidase.

Substrate specificity and some other enzymatic properties of partial purified endo-beta-N-acetylglucosaminidases (endo-beta-GlcNAc-ase) from developing soybean seeds (Glycine max, Endo-GM) and developing tomato fruits (Lycopersicum esculentum, Endo-LE) were studied. The substrate specificity of these two endoglycosidases was explored and compared with regard to various pyridylaminated N-glycans derived from some naturally occurring glycoproteins. For Endo-GM and Endo-LE, several high mannose-type sugar chains bearing alpha 1-2 mannosyl residue(s), Man9-6GlcNAc2-PA (PA is pyridylamino) (80-100% relative hydrolysis), were most favored substrates followed by Man5GlcNAc2-PA (32% for Endo-LE, 43% for Endo-GM), a typical hybrid-type structure (GlcNAc1Man5GlcNAc2-PA; 34% for Endo-LE, 37% for Endo-GM), and then the common core pentasaccharide of N-glycan (Man3GlcNAc2-PA; 9% for Endo-GM and 16% for Endo-LE). On the contrary, both Endo-GM and Endo-LE could barely hydrolyze the xylose-containing N-glycans (Man3Xyl1GlcNAc2-PA, Man3Fuc1Xyl1GlcNAc2-PA) found ubiquitously in plant cells. The molecular mass of these two endoglycosidases was approximately 62 kDa by gel filtration and both Endo-GM and Endo-LE showed maximal activities for Man6GlcNAc2-PA in a weak acidic region (pH 6.0-6.5).

Role of microtubules in the contractile dysfunction of hypertrophied myocardium.

OBJECTIVES: We sought to determine whether the ameliorative effects of microtubule depolymerization on cellular contractile dysfunction in pressure overload cardiac hypertrophy apply at the tissue level. BACKGROUND: A selective and persistent increase in microtubule density causes decreased contractile function of cardiocytes from cats with hypertrophy produced by chronic right ventricular (RV) pressure overloading. Microtubule depolymerization by colchicine normalizes contractility in these isolated cardiocytes. However, whether these changes in cellular function might contribute to changes in function at the more highly integrated and complex cardiac tissue level was unknown. METHODS: Accordingly, RV papillary muscles were isolated from 25 cats with RV pressure overload hypertrophy induced by pulmonary artery banding (PAB) for 4 weeks and 25 control cats. Contractile state was measured using physiologically sequenced contractions before and 90 min after treatment with 10(-5) mol/liter colchicine. RESULTS: The PAB significantly increased RV systolic pressure and the RV weight/body weight ratio in PAB; it significantly decreased developed tension from 59+/-3 mN/mm2 in control to 25+/-4 mN/mm2 in PAB, shortening extent from 0.21+/-0.01 muscle lengths (ML) in control to 0.12+/-0.01 ML in PAB, and shortening rate from 1.12+/-0.07 ML/s in control to 0.55+/-0.03 ML/s in PAB. Indirect immunofluorescence confocal microscopy showed that PAB muscles had a selective increase in microtubule density and that colchicine caused complete microtubule depolymerization in both control and PAB papillary muscles. Microtubule depolymerization normalized myocardial contractility in papillary muscles of PAB cats but did not alter contractility in control muscles. CONCLUSIONS: Excess microtubule density, therefore, is equally important to both cellular and to myocardial contractile dysfunction caused by chronic, severe pressure-overload cardiac hypertrophy.

The role of amino acids surrounding tyrosine 1062 in ret in specific binding of the shc phosphotyrosine-binding domain.

We investigated the role of the I-E-N-K-L (amino acids 1057-1061) sequence amino-terminal to Tyr1062 in Ret for binding of the Shc phosphotyrosine-binding (PTB) domain. Substitution of Ser for Ile1057 (I1057S), Ala for Asn1059 (N1059A), or Pro for Leu1061 (L1061P) in this sequence significantly decreased the transforming activity of Ret with the multiple endocrine neoplasm type 2A (MEN2A) mutation as well as the binding affinity of Shc to it in vivo and in vitro, indicating that these three amino acids play a role in Shc binding. In addition, as the RET protooncogene is translated as three isoforms of 1114 amino acids (Ret 51), 1106 amino acids (Ret 43), and 1072 amino acids (Ret 9) that differ from one another in the sequence carboxyl-terminal to Tyr1062, we examined whether these sequence differences influence the binding affinity of Shc to Ret. As a result, we found that the transforming activity of Ret 43 isoform with the MEN2A mutation and the binding affinity of Shc to it were very low, although the consensus sequence for the binding of the Shc PTB domain is conserved in the Ret 43 isoform. This finding suggested that the sequence carboxyl-terminal to Tyr1062 in Ret could also influence the binding affinity to Shc.

Consumption of carotenoids in photosensitized oxidation of human plasma and plasma low-density lipoprotein.

Human plasma and plasma low-density lipoprotein (LDL) were exposed to photoirradiation in the presence of methylene blue (water-soluble photosensitizer) or 12-(1-pyrene)dodecanoic acid (P-12, lipid-soluble photosensitizer). In methylene-blue-sensitized photooxidation of human plasma and LDL, endogenous carotenoids and tocopherols were consumed with the accumulation of cholesteryl ester hydroperoxides (CE-OOH). Xanthophylls (zeaxanthin and lutein) decreased faster than lycopene and carotenes in the case of human plasma. In P-12-sensitized photooxidation of human plasma and LDL, the decrease rate of xanthophylls was slower than that of lycopene and carotenes. A lower level of beta-carotene exerted the effective inhibition of lipid peroxidation and retarded the oxidative loss of alpha-tocopherol, when the phosphatidylcholine liposomes containing these two lipid-soluble antioxidants were subjected to methylene blue- or P-12-sensitized photooxidation. These results suggest that antioxidant activity of carotenoids in photosensitized oxidation (Type II) of human plasma LDL depends on the site of singlet oxygen (1O2) to be generated and that carotenoids can protect tocopherols from the oxidative loss by 1O2 in the plasma.

Specific quantitation of secretory immunoglobulin A with enzyme immunoassay using activated thiol--Sepharose for separation method.

A specific and sensitive enzyme immunoassay system for human secretory IgA was developed using anti-alpha-chain antibodies coupled to activated thiol-Sepharose, and anti-secretory component antibodies labeled with beta-D-galactosidase from Escherichia coli. The dose response of the enzyme activity in eluate was observed between 3 and 1000 ng of secretory IgA with little cross-reactions with IgA, IgG, IgM and secretory component. The assay method could be employed for the measurement of secretory IgA in saliva, urine, feces, intestine and serum without interferences by the abundant IgA in the same samples.

Nervous system-specific enolase in serum as a marker for neuroblastoma.

Serum levels of nervous system-specific enolase (alpha gamma form plus gamma gamma form) were determined in 18 patients with neuroblastoma and in 40 control infants by means of a sandwich enzyme immunoassay method specific to the gamma subunit (or 14-3-2 protein) of enolase isozymes. Levels in patients with neuroblastoma were elevated (mean, 70.3; range, 6.2 to 330.0 ng/mL) when compared with those of control subjects (4.3 +/- 1.7 ng/mL). Most of the patients (6/7), whose serum nervous system-specific enolase level increased more than 100 ng/mL, died within 1 month. Serial measurements in patients with neuroblastoma receiving various therapies have revealed that there was a good correlation between serum nervous system-specific enolase levels and the course of the disease. These results indicate that the nervous system-specific enolase in serum may be a valuable marker for therapeutic monitoring of patients with neuroblastoma, as reported recently in patients with small-cell carcinoma of the lung.

Genetic analysis of the susceptibility in rats to aberrant crypt foci formation by 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine, PhIP.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most abundant heterocyclic amine produced while cooking fish and meat, induces aberrant crypt foci (ACF) and colon cancers in rats. We previously reported that F344 rats were sensitive and ACI rats resistant to ACF formation by PhIP, and that the genetic susceptibility in F344 rats to ACF formation by PhIP was autosomally dominant over ACI rats. To identify candidate susceptibility genes in F344 rats, a preliminary genome-wide linkage analysis was employed using a subset of 170 progeny of (F344 x ACI)F1 x ACI backcross rats with either high or low sensitivity to ACF formation by PhIP. Three chromosomes, 1, 6 and 16, demonstrated the presence of loci with a logarithm of the odds (lod) scores of more than 1.0, and a susceptible gene for ACF formation by PhIP was suggested to reside on chromosomes 16.

Prognostic impact of telomerase activity in patients with neuroblastoma.

Neuroblastoma is one of the most common malignant neoplasms occurring among children. The prognosis for this disease is strongly associated with age, disease stage, histology, and some biologic features. It has been reported that telomerase, a ribonucleoprotein enzyme, which maintains the telomere length in immortal cells, is related to disease stage and other biologic features. The purpose of this study was to evaluate the prognostic value of telomerase activity compared to TrkA expression in 65 patients with neuroblastoma. Telomerase activity and TrkA expression were examined in tissue samples collected between 1980 and 1994 from 65 patients by polymerase chain reaction-based telomerase activity. TrkA expression was examined by immunoblotting using a rabbit anti-gp140 proto-trk polyclonal antibody. Low telomerase activity was found in 22 of 30 (73.3%) patients with Stages 1, 2, or 4S neuroblastomas; 7 of 13 (53.8%) with Stage 3; and 8 of 22 (36.3%) with stage 4; no telomerase activity was detected in 7 of 22 (31.8%) patients with Stage 4 neuroblastoma. The 5-year event-free survival (EFS) rate was 86.5% for patients with low telomerase activity, while it was 53.8% for patients with high telomerase activity. By the combination of telomerase activity and TrkA expression, the 5-year EFS rate was highest among patients with a high TrkA expression and a low or non-existent telomerase activity (91.7%), and it was lowest among patients with a low TrkA expression and a high telomerase activity (29.6%). Thus, it appears that telomerase activity would be a useful prognostic factor for neuroblastoma, especially when used in combination with the TrkA expression.

New neonatal extracorporeal membrane oxygenation circuit with a self-regulating blood pump.

BACKGROUND: Because a roller pump used in a conventional extracorporeal membrane oxygenation (ECMO) circuit with a roller pump cannot change the output automatically according to the venous return, ECMO management requires considerable personnel to prevent serious mechanical complications. An automatic blood pump will make ECMO less laborious and safer. METHODS: Takagi's self-regulating blood pump was modified for neonatal ECMO. The new ECMO circuit was tested in a simulation circuit, in puppies, and in two neonates clinically. Self-regulation of the pump was studied in response to various hemodynamic conditions. RESULTS: The priming volume including a membrane lung and a heat exchanger was about 90 ml. The maximum flow was 700 ml/min in the simulation circuit, 101 ml/min/kg in puppies, and 113 and 135 ml/min/kg in two newborns, respectively. ECMO flow was self-regulating and stable in response to hemodynamic changes. The blood pumps remained functional for more than 400 hours in puppies and 67 and 149 hours in the two newborns, respectively. CONCLUSIONS: The new automatic ECMO circuit is more reliable and requires less personnel than a conventional ECMO circuit.

Distribution of nervous system-specific forms of enolase in peripheral tissues.

The distribution of 3 forms of rat enolase (alpha alpha, alpha gamma and gamma gamma forms), including nervous system-specific forms (alpha gamma and gamma gamma), was determined in various tissues with a sensitive enzyme immunoassay system. The brain and spinal cord contained more than 100 pmol/mg protein of the alpha alpha, alpha gamma and gamma gamma enolases. Organs such as the lungs, heart, spleen, liver, and kidney contained similarly high levels of alpha alpha enolase, but these tissues contained alpha gamma and gamma gamma enolases at levels less than 1% of the central nervous tissues. High levels of the alpha gamma (greater than 10 pmol/mg) and the gamma gamma (greater than 1.5 pmol/mg) forms were found in rectum, bladder, and uterus. In gut, major portions of the nervous system-specific forms were localized in the muscle layers. Skeletal muscle and diaphragm, which are composed of striated muscle, contained low levels of 3 forms of enolase. Megakaryocytes separated from the suspension of bone marrow contained 11.3, and 0.53 amol/cell of the alpha alpha and gamma gamma enolases, respectively, with little, if any, of the alpha gamma form.

Mutagenic potency of chlorofuranones and related compounds in Salmonella.

One of the mutagenic byproducts associated with chlorinated humic waters and kraft pulp bleaching effluents was recently identified as 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone. This compound and several related chlorofuranones and precursors were synthesized and evaluated for direct-acting mutagenicity in Salmonella typhimurium tester strain TA100. Mutagenicity was greatest for 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone, its 5-methoxy derivative, and the precursor in their synthesis, 3-(dichloromethyl)-2,4,4-trichloro-2-butenoic acid. Several of the compounds were tested in the presence of added rat liver homogenate S9 fraction, and in all cases mutagenicity was substantially reduced. An important structural feature which may govern the mutagenic response in these instances appears to be the cis arrangement of CHCl2 and Cl substituents on a carbon-carbon double bond. These compounds may also be transformed in vitro to the same acyclic chlorine substituted alpha, beta-unsaturated aldehyde derivative, which is proposed to be the agent responsible for the observed mutagenicity.

Dictyophorines A and B, two stimulators of NGF-synthesis from the mushroom Dictyophora indusiata.

Two novel eudesmane-type sesquiterpenes, dictyophorines A and B, and a known compound, teucrenone, were isolated from the mushroom Dictyophora indusiata. Dictyophorines A and B promoted nerve growth factor (NGF)-synthesis by astroglial cells.

A pyradine-derivative from the mushroom Albatrellus confluens.

A novel pyradine-derivative was isolated from the mushroom Albatrellus confluens. This compound promoted melanin synthesis by B16 melanoma cells.