Characterization of a vitamin B12 compound from unicellular coccolithophorid alga (Pleurochrysis carterae)

A unicellular coccolithophorid alga, Pleurochrysis carterae, contained 125.4 +/- 1.2 microg of vitamin B12 per 100 g dry cell weight of the lyophilized algal cells. A vitamin B12 compound was purified from the lyophilized algal cells and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B12, but not those of vitamin B12 analogues inactive for humans. When 22-week-old B12-deficient rats which excreted substantial amounts of methylmalonic acid (75.5 +/- 12.3 mg/day) in urine were fed the P. carterae (10 g per kg diet)-supplemented diet for 12 d, urinary methylmalonic acid excretion (as an index of vitamin B12 deficiency) of the rats became undetectable and hepatic vitamin B12 level of the rats was significantly increased.

Feeding dried purple laver (nori) to vitamin B12-deficient rats significantly improves vitamin B12 status

To clarify the bioavailability of vitamin B12 in lyophylized purple laver (nori; Porphyra yezoensis), total vitamin B12 and vitamin B12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B12-deficient rats were investigated. The amount of total vitamin B12 in the dried purple laver was estimated to be 54.5 and 58.6 (se 5.3 and 7.5 respectively) microg/100 g dry weight by Lactobacillus bioassay and chemiluminescent assay with hog intrinsic factor respectively. The purple laver contained five types of biologically active vitamin B12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin B12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin B12. When 9-week-old vitamin B12-deficient rats, which excreted substantial amounts of methylmalonic acid (71.7(se 20.2) micromol/d) in urine, were fed the diet supplemented with dried purple laver (10 microg/kg diet) for 20 d, urinary methylmalonic acid excretion (as an index of vitamin B12 deficiency) became undetectable and hepatic vitamin B12 (especially adenosylcobalamin) levels were significantly increased. These results indicate that vitamin B12 in dried purple laver is bioavailable to rats.

Artificial Pseudomonas aeruginosa biofilms and confocal laser scanning microscopic analysis

Bacterial biofilms may be formed at various sites, including mucous membranes, teeth, and infectious lesions. To elucidate the structure and the function of biofilms, artificial biofilms of mucoid-type Pseudomonas aeruginosa organisms (strain PT1252) were made by centrifuging the organisms onto the surface of a coverglass and culturing further in broth media supplied continuously (45 ml/h). The biofilm structure at 4, 8, 12, and 24 h was visualized with fluorescent staining (SYTO9, propidium iodide [PI], and/or fluorescein isothiocyanate-concanavalin A [FITC-ConA]) by confocal laser scanning microscopy (CLSM). It was clearly demonstrated that the number of bacteria (10(4)--10(6)/ml) could be estimated by their fluorescence intensity. Sectional analysis of each biofilm layer (1-microm thickness) made it possible to demonstrate the three-dimensional development of biofilms, and revealed that the biofilms were 9 microm in height after 12 h. The live and dead organisms were differentiated by SYTO9 and PI, respectively, in situ in biofilms, and about 13% of the organisms were dead in 12-h-old biofilms. When 12-h-old biofilms were exposed to ciprofloxacin at minimum bactericidal concentration (6.26 microg/ml) for 90 min, all the organisms were killed, but some organisms (11 +/- 1.3%; n = 3) in 24-h-old biofilms with thicker and denser structure were still alive after exposure for 120 min. These results indicate that the CLSM analysis of artificial biofilms was useful for elucidating bacterial functions in biofilms, and may lead to a new quantitative system for estimating the bactericidal efficacy of antibacterial drugs in biofilms.

[Follow-up survey of dioxins in the blood of Yusho patients (in 1998-1999)]

Follow-up survey of the blood concentration of PCDDs, PCDFs and non-ortho-chlorine substituted PCBs in Yusho patients is very important for their health control. We determined the blood concentration of these dioxin isomers in 119 blood samples collected in 1998 and 1999 using by a high-resolution gas chromatograph/high-resolution mass spectrometry (HRGC/HRMS). Thirty years had passed since the Yusho occurrence, and the total blood concentrations of PCDFs in the blood of Yusho patients were still as high as ever, except the patients with the PCB pattern C. Among the different groups of PCB patterns, the concentration of 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF and 1,2,3,6,7,8-HxCDF showed significant differences, excluding the group BC because of the small number of cases. The findings indicate that these isomers are not decomposed in human body since they had highly contaminated the causal rice oil at the onset. In typical Yusho patients (Group A of PCB pattern), the mean TEQ concentrations of PCDDs, PCDFs and non-ortho-chlorine substituted PCBs in the blood collected in 1998 were 21, 206, and 14 pg-TEQ/g lipid, respectively, and in 1999, 30, 308 and 14 pg-TEQ/g lipid, respectively. The toxic contribution rate of PCDFs TEQ was still at high levels for total TEQ in both years. The patients of the group C, however, the mean blood levels of the dioxins TEQ in 1998 and 1999 did not differ from those of the normal controls determined in 1996 although some patients in this group showed a high toxic contribution rate of PCDFs TEQ for total TEQ. We will try the PCB isomer specific analysis of the Yusho patients blood, and will investigate the difference from normal controls blood.

Characterization of vitamin B12 compounds from edible shellfish, clam, oyster, and mussel

Vitamin B12 content of various edible shellfish was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor-chemiluminescence methods. The values determined by the microbiological method were 1.2-19.8 (M/C ratio) fold greater in the shellfish than the values determined by the chemiluminescence method. Vitamin B12 compounds were purified from most eaten shellfish, oyster (M/C, 1.5), mussel (M/C, 1.2), and short-necked clam (M/C, 2.7), and partially characterized. TLC and HPLC patterns of each red-colored vitamin B12 compound (M/C, 1.0-1.2) purified from these shellfish were identical to those of authentic vitamin B12. Although the higher values in the determination of vitamin B12 by the microbiological method may be due to the occurrence of vitamin B12-substitutive compounds, the edible shellfish would be excellent vitamin B12 sources judging from the values (> or = 6 micrograms/100 g) determined by the chemiluminescence method.

Base mutation analysis by a ferrocenyl naphthalene diimide derivative

An electrochemical DNA sensing technique was developed by using ferrocenyl naphthalene diimide coupled with a probe DNA-immobilized electrode. This technique enabled detection of target DNA quickly and with high sensitivity. Applicability of this technique for single nucleotide polymorphisms (SNPs) analysis was demonstrated by successful analysis of a DNA mismatch on the cancer repression gene p53 with high precision.

Covalent glutathione conjugation to cyanobacterial hepatotoxin microcystin LR by F344 rat cytosolic and microsomal glutathione S-transferases

Most investigators report that microcystins (MCs) bound covalently to SH compounds, such as L-cysteine and reduced glutathione (GSH). However, their studies were based on a high pH condition. In the present study, we investigated the reaction between microcystin LR (MCLR) and GSH in various pH conditions. As a result, we found that no MCLR conjugated with GSH in these conditions, and MCLR mixed with GSH showed different peaks of retention time compared with intact MCLR on the high performance liquid chromatography-mass spectrometry (LC-MS) chromatograms. Furthermore, we found the GSH conjugate of MCLR was detected in the glutathione S-transferase (GST) assay using F344 rat liver cytosol and microsomes. This indicates that the covalent GSH conjugation was caused only by an enzymatic activity. We conclude, therefore, that the reaction is caused by enzymatic action and is not due to the Michael reaction.

Characterization of silica-supported Ni catalysts effective for methane decomposition by Ni K-edge XAFS

The structural change of Ni species during the methane decomposition into hydrogen and carbon over Ni/SiO2 catalyst was investigated by Ni K-edge XANES/EXAFS. Before the contact of methane with the Ni/SiO2 catalyst, Ni species were present as Ni metal mainly. The structure of the Ni metal did not change appreciably when the Ni/SiO2 was actively decomposing methane. In contrast, the formation of nickel carbide species was observed at the deactivation stage of the catalyst.

Influence of starvation and biofilm formation on acid resistance of Streptococcus mutans

The aim of this study was to investigate acid resistance induced by starvation or biofilm formation in Streptococcus mutans ATCC 25175. The artificial biofilms were made on cover glasses, starved for 24 h and immersed in 0.1 M lactate buffer at pH 3.8 for 10 min. The biofilms were also exposed to 5% sucrose solution for 20 min to simulate acid shock produced by sucrose metabolism. Confocal laser scanning microscopy with fluorescein isothiocyanate staining measured the resultant minimum pH in biofilms. Live and dead organisms in biofilms were differentiated by confocal laser scanning microscopy with proidium iodide and SYTO9 staining. The same processes were used to treat planktonic organisms. The results showed that starved biofilms or planktonic cells showed significantly more viable bacteria after acid shock induced either by lactic acid or during sucrose consumption than non-starved biofilms or planktonic cells. In addition, biofilms showed greater resistance to acid shock induced by lactic acid than planktonic cells, whereas similar results were obtained where sucrose was used as a carbon source to reduce pH in biofilms and planktonic cells. Thus, it is suggested that starvation protects both biofilm and planktonic S. mutans from acid shock induced either by lactic acid or during sucrose consumption, while biofilm formation seemed to protect bacteria only from acid shock induced by pH 3.8 lactate buffer but not the acid shock of a slightly higher pH produced during sucrose consumption.

Extracellular polysaccharides do not inhibit the reaction between Streptococcus mutans and its specific immunoglobulin G (IgG) or penetration of the IgG through S. mutans biofilm

The present study investigated whether extracellular polysaccharides inhibit reaction between Streptococcus mutans and its specific immunoglobulin G (IgG) and penetration of the IgG through S. mutans biofilm. The planktonic organisms with or without extracellular polysaccharides were prepared, incubated with rabbit IgG against whole cell of S. mutans and fluorescein isothiocyanate (FITC)-conjugated goat affinity purified antibody to rabbit IgG. Biofilms with or without extracellular polysaccharides were formed on cover glasses and incubated with rabbit IgG against S. mutans and FITC-conjugated goat antibody to rabbit IgG. Then, biofilms were stained with propidium iodide. The amount of specific IgG binding on S. mutans was determined by FITC intensity with a fluorescence microplate reader. The penetration of IgG through biofilms was determined by confocal laser scanning microscopy. The results showed that the fluorescence intensity of FITC in planktonic organisms with extracellular polysaccharides was similar to that in planktonic organisms without extracellular polysaccharides, indicating that extracellular polysaccharides did not inhibit the reaction between S. mutans and its specific IgG. Although biofilms of S. mutans with extracellular polysaccharides were much thicker and denser than those without extracellular polysaccharides, the speed with which IgG penetrated through both of the biofilms did not differ significantly, suggesting that penetration of IgG through S. mutans biofilm was not affected by extracellular polysaccharides.

Relatively benign clinical course in asymptomatic patients with brugada-type electrocardiogram without family history of sudden death

INTRODUCTION

The incidence of sudden death or ventricular fibrillation (VF) in asymptomatic Brugada syndrome patients with a family history of sudden death is reported to be very high. However, there are few reports on the prognosis of asymptomatic Brugada syndrome patients without a family history of sudden death.

METHODS AND RESULTS

Eleven patients (all male; mean age 40.5 +/- 9.6 years, range 26 to 56) with asymptomatic Brugada-type ECG who had no family history of sudden death were evaluated. The degrees of ST segment elevation and conduction delay on signal-averaged ECG (SAECG) before and after pilsicainide were evaluated in all 11 patients. VF inducibility by ventricular electrical stimulation also was evaluated in 8 of 11 patients. Patients were followed for a period of 9 to 84 months (mean 42.5 +/- 21.6). The J point level was increased (V1: 0.19 +/- 0.09 mV to 0.36 +/- 0.23 mV; V2: 0.31 +/- 0.12 mV to 0.67 +/- 0.35 mV) by pilsicainide. Conduction delay was increased (total QRS: 112.2 +/- 6.3 msec to 131.7 +/- 6.3 msec; under 40 microV: 42.0 +/- 8.5 msec to 52.7 +/- 12.7 msec; last 40 msec: 17.4 +/- 5.9 microV to 10.4 +/- 6.1 microV) on SAECG by pilsicainide. VF was induced in only 1 of 8 patients. None of the patients had syncope or sudden death during a mean follow-up of 42.5 +/- 21.6 months.

CONCLUSION

This study suggests that asymptomatic patients with Brugada-type ECG who have no family history of sudden death have a relatively benign clinical course.

Characterization of a vitamin B12 compound in the edible purple laver, Porphyra yezoensis

The edible purple laver, Porphyra yezoensis, contained 51.49+/-1.51 microg of vitamin B12 compounds per 100 g dry weight of the laver (mean +/- SEM, n = 4). A vitamin B12 compound was purified from the lyophilized purple laver and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B12, but not to those of vitamin B12 analogues inactive for humans.

[Chemoradiotherapy with low-dose cisplatin and 5-FU for advanced esophageal cancer]

We evaluated the efficacy of chemoradiotherapy (CRT) for advanced esophageal cancer, from the view point of response. The relationship between chemo-radiosensitivity and dihydropyridine dehydrogenase (DPD), thymidylate synthase (TS), and p53 was investigated immunohistochemically. Thirteen patients with inoperable advanced esophageal cancer were involved in this study. CDDP of 10 mg/m2/day and 5-FU of 335 mg/m2/day were infused intravenously (day 1-5, day 15-19). Radiation was delivered concomitantly at a total dose of 30 Gy. Expressions of p53, DPD and TS were detected using immunohistology in the biopsy samples taken before CRT from 8 patients. Partial response was observed in 8 cases, no change in 4 cases, and progressive disease in one case. The overall response rate was 62%. The reduction rate was higher in tumors positive for p53 expression than in negative ones. The same was true for DPD and TS. The Treatment effect was more precisely predicted by combination of p53, DPD and TS. CRT with low-dose CDDP + 5-FU chemotherapy was effective and combination with p53, DPD, and TS might be a predictive marker for CRT in patients with advanced esophageal cancer.

Structural and biosynthetic studies of a principal bile alcohol, 27-nor-5beta-cholestane-3alpha,7alpha,12alpha,24,25-pentol, in human urine

The stereochemistry at C-24 and C-25 of 27-nor-5beta-cholestane-3alpha,7alpha,12alpha,24 ,25-pentol, a principal bile alcohol in human urine, and its biosynthesis are studied. Four stereoisomers of the C(26)-24,25-pentols were synthesized by reduction with LiAlH(4) of the corresponding epoxides prepared from (24S)- or (24R)-27-nor-5beta-cholest-25-ene-3alpha, 7alpha,12alpha,24-tetrol. The stereochemistries at C-25 were deduced by comparison of the C(26)-24,25-pentols with the oxidation products of (24Z)-27-nor-5beta-cholest-24-ene-3alpha,7alpha, 12alpha-triol with osmium tetraoxide. On the basis of this assignment, the principal bile alcohol excreted into human and rat urine was determined to be (24S,25R)-27-nor-5beta-cholestane-3alpha,7alpha, 12alpha,24,25-pentol, accompanied by a lesser amount of (24R, 25R)-isomer. To elucidate the biosynthesis of the C(26)-24,25-pentol, a putative intermediate, 3alpha,7alpha, 12alpha-trihydroxy-27-nor-5beta-cholestan-24-one, derived from 3alpha,7alpha, 12alpha-trihydroxy-24-oxo-5beta-cholestanoic acid by decarboxylation during the side-chain oxidation of 3alpha,7alpha, 12alpha-trihydroxy-5beta-cholestanoic acid, was incubated with rat liver homogenates. The 24-oxo-bile alcohol could be efficiently reduced to yield mainly (24R)-27-nor-5beta-cholestane-3alpha,7alpha, 12alpha,24-tetrol. If a 25R-hydroxylation of the latter steroid occurs, it should lead to formation of (24S,25R)-C(26)-24,25-pentol. Now it has appeared that a major bile alcohol excreted into human urine is (24S,25R)-27-nor-5beta-cholestane-3alpha,7alpha, 12alpha, 24, 25-pentol, which might be derived from 3alpha,7alpha, 12alpha-trihydroxy-27-nor-5beta-cholestan-24-one via (24R)-27-nor-5beta-cholestane-3alpha, 7alpha,12alpha,24-tetrol.

Complete nucleotide sequence and functional analysis of the genes for 2-aminophenol metabolism from Pseudomonas sp. AP-3

A 13.9-kb region, which contained the 2-aminophenol 1,6-dioxygenase genes (amnBA) reported before, was cloned from the 2-aminophenol-assimilating bacterium Pseudomonas sp. AP-3. The complete nucleotide sequence of this region was determined and six genes were found downstream of amnBA. The eight genes together were designated amnBACFEDHG. Each gene was similar to the corresponding gene operating in the meta-cleavage pathway, except for amnB, amnA, and amnD. The four 2-aminophenol-metabolizing enzymes, 2-aminomuconic 6-semialdehyde dehydrogenase, 2-aminomuconate deaminase, 4-oxalocrotonate decarboxylase, and 2-oxopent-4-enoate hydratase, were purified and characterized. NH2-terminal amino acid sequences of each purified enzyme agreed with those deduced from amnC, amnF, amnE, and amnD, respectively. These genes were therefore assigned as the genes encoding these respective proteins. The tight clustering of the amn genes, which were all transcribed in the same direction, raised the possibility that these genes formed a single operon. The organization of the amn genes was entirely different from that of the atd, dmp, and xyl genes reported in the meta-cleavage pathway, although these latter genes clustered similarly.

DNA coated with cationic fullerene derivative. A possible microwire in water

Fullerene derivative 2 carrying pyridinium cation bound to sonicated calf thymus DNA in water. The binding ratio was 1 fullerene unit to 1 phosphate residue, giving the complex where DNA strand is seemingly coated with electron-conducting fullerenes. Cyclic voltammetry shows three-step redox couples in the complex, and the current peaks were broadened and shifted to positive side as compared to uncomplexed 2. Binding of 2 onto grooves of DNA double helix was suggested.

Highly sensitive detection of target gene by electrochemical method

A highly sensitive DNA sensing method was developed using electrochemically active ligand. This method is based on the detection of electric current generated by electrochemically active ligand concentrated on the electrode. Electrochemically active, intercalating ligand can bind to the double stranded DNA of target gene sequence on the electrode, where the complementary single strand is immobilized as a probe. We succeeded in the detection of 0.1 amol target gene. The technique was applicable to the detection of 0.1-10 amol gene.

DNA sensing on a DNA probe-modified electrode using ferrocenylnaphthalene diimide as the electrochemically active ligand

Naphthalene diimide derivative 1 carrying ferrocenyl moieties at the termini of imide substituents binds intact calf thymus DNA 4 times more strongly than the denatured DNA, and its complex with the intact DNA dissociates 80 times more slowly than that with the denatured DNA. On the basis of these observations, ligand 1 was applied to a probe of electrochemical DNA sensing. A thiol-linked single-stranded DNA probe was immobilized through the S-Au bonding to 20-30 pmol/mm2 on a gold electrode. Following hybridization with the complementary DNA, the electrode was soaked in a solution containing 1 (intercalation step) and then washed with buffer for 5 s. The cyclic voltammogram and differential pulse voltammogram for this electrode gave an electrochemical signal due to the redox reaction of 1 that was bound to the double-stranded DNA on the electrode. Thus, dA20 and the yeast choline transport gene were quantitated at the subpicomole level. The sensitivity of DNA detection was improved to 10 zmol by reducing the amount of immobilized DNA probe and protecting the uncovered surface of the electrode with 2-mercaptoethanol.

Pseudovitamin B(12) is the predominant cobamide of an algal health food, spirulina tablets

The vitamin B(12) concentration of an algal health food, spirulina (Spirulina sp.) tablets, was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor chemiluminescence methods. The values determined with the microbiological method were approximately 6-9-fold greater in the spirulina tablets than the values determined with the chemiluminescence method. Although most of the vitamin B(12) determined with the microbiological method was derived from various vitamin B(12) substitutive compounds and/or inactive vitamin B(12) analogues, the spirulina contained a small amount of vitamin B(12) active in the binding of the intrinsic factor. Two intrinsic factor active vitamin B(12) analogues (major and minor) were purified from the spirulina tablets and partially characterized. The major (83%) and minor (17%) analogues were identified as pseudovitamin B(12) and vitamin B(12), respectively, as judged from data of TLC, reversed-phase HPLC, (1)H NMR spectroscopy, ultraviolet-visible spectroscopy, and biological activity using L. leichmannii as a test organism and the binding of vitamin B(12) to the intrinsic factor.

Urinary bile alcohol profile in infants with intrahepatic cholestasis: identification of 5beta-cholestane-3alpha,7alpha,24,25-tetrol

Urinary bile acids and bile alcohols were examined in six infants aged between 1 and 6 mo who had intrahepatic cholestasis. Following extraction, hydrolysis and solvolysis, cholanoids were analysed by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry. The relative ratio of the urinary excretion of bile alcohols to bile acids was very low (0.07-0.22) in three patients with mild to severe cholestasis, whereas the urinary excretion of bile alcohols was 2-4 times greater than that of the total bile acids in three patients with slight cholestasis. The urinary bile alcohol spectrum in infants appears to be quite different from that in adults. Although the major bile alcohol was 27-nor-5beta-cholestane-3alpha,7alpha,12alpha,24 ,25-pentol, comprising more than 50% of total urinary bile alcohols in healthy adults, it accounted for only 35% of total urinary bile alcohols in our patients. In addition, bile alcohols carrying chenodeoxycholic acid type nucleus were detected in our patients by comparison of the retention times and mass spectra with those of authentic standards. The presence of 5beta-cholestane-3alpha,7alpha,24,25-tetrol confirmed for the first time in this study may represent an alternative pathway for chenodeoxycholic acid biosynthesis via a "25-hydroxylation pathway" in early life.

Asymptomatic form of Brugada syndrome

We describe a patient with the asymptomatic form of Brugada syndrome. His electrographical, electropharmacological, and electrophysiological characteristics were similar to those reported in patients with the symptomatic form of Brugada syndrome. We believe that he has the same arrhythmogenic substrate as that of patients with Brugada syndrome. The fact that he had no episode of spontaneous ventricular fibrillation might be explained by his absence of the triggering factors.

Characterization of a novel monoclonal antibody that senses nitric oxide-dependent activation of soluble guanylate cyclase

Two monoclonal antibodies (mAbs) against bovine lung soluble guanylate cyclase (sGC) were prepared and characterized. mAb 3221 recognized both the alpha- and beta-subunits of sGC and had greater binding affinity to the enzyme in the presence of NO. mAb 28131 recognized only the beta-subunit and its affinity did not change with NO. Neither mAb cross-reacted with particulate GC. Cultured Purkinje cells from rats were treated with S-nitroso-N-acetylpenicillamine, an NO donor, and examined by immunocytochemical methods. The immunoreactivity associated with mAb 3221 increased with the cGMP content in a crude extract of cerebellum and the NO2 generated in the culture medium increased.