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PubMed1994

Removal of latex glove contaminants prior to taking poly (vinylsiloxane) impressions.

Sulfur compounds found in latex gloves may be deposited on teeth and gingiva, inhibiting the setting of poly(vinylsiloxane) impression materials. The objective of this in vivo study was to screen a variety of methods to remove these contaminants. Ten patients were each tested with eight decontamination methods. Before each trial, the facial surfaces and adjacent gingiva of the maxillary central and lateral incisors were contaminated with 20 wipes of a latex glove. Decontamination methods included a 30-second rinse with mouthwash, 3% hydrogen peroxide, or air-water syringe; a 30-second toothbrush scrub with water, mouthwash, or hydrogen peroxide; a 30-second cotton pellet-Cavidry scrub; and a 30-second cleaning with a prophy cup and pumice. A 10-second water rinse followed each method except the air-water syringe and Cavidry groups. A low-viscosity poly(vinylsiloxane) impression material was then used to take an impression of the area. To test surface inhibition, the gingival, tooth, and palatal impression surfaces were wiped with cotton-tipped applicators, and the degree of inhibition was subjectively categorized by two independent investigators. Mechanical decontamination with a toothbrush or pumice was significantly more effective than was rinsing alone, regardless of the solution used.

Analysis of Variance↗
PubMed2026

Symbiosis reshapes metabolism of sulfate-reducing bacteria in gutless marine worms.

Sulfate-reducing bacteria (SRB) are widespread in marine and terrestrial environments, where they often form syntrophic associations with bacteria, archaea, and eukaryotes. Among the most intimate of these are multipartite symbioses in gutless marine oligochaete worms, which host SRB and sulfur-oxidizing endosymbionts that engage in a syntrophic exchange of sulfur compounds. Despite decades of research on free-living SRB, the metabolic traits that enable SRB to persist in symbiosis, and how these differ across hosts and environments, remain poorly understood. We show that a globally distributed clade of symbiotic SRB, which we named Candidatus Desulfoconcordia, has a conserved core metabolism that diverges from free-living relatives. Using comparative genomics and metaproteomics, we reveal that these endosymbionts retain key traits of SRB such as sulfate reduction, complete oxidation of acetate to CO2, amino acid degradation for nitrogen acquisition, and transport of essential nutrients. However, they exhibit a more oxygen-tolerant metabolism and lack typical nutrient-scavenging mechanisms of free-living SRB. One trait, the glyoxylate bypass, was consistently expressed in situ and may serve both in reactive oxygen species defence and in biomass generation. The expression of oxygen-tolerant pathways, coupled with the loss of nutrient-scavenging functions, indicate specialization to a host-associated, redox-fluctuating environment distinct from that of free-living SRB. The symbiont genomes are also larger than those of free-living relatives, contrasting with genome reduction in many endosymbionts and reinforcing the importance of metabolic versatility. Our findings provide a framework for understanding how metabolic flexibility enables SRB to persist in long-term multipartite symbioses across diverse marine ecosystems.

Symbiosis↗
PubMed2005

A combined therapeutic approach to manage oral halitosis: a 3-month prospective case series.

BACKGROUND: Clinical research assessing different therapeutic protocols aimed at treating oral halitosis is scarce. The aim of this study was to evaluate the effects of a combined mechanical and pharmacological approach to treat oral halitosis on clinical and microbiological outcomes on patients followed for 3 months. METHODS: Nineteen subjects with oral malodor participated. At baseline, all subjects completed a questionnaire and carried out an examination including full-mouth organoleptic and volatile sulfur compound (VSC) levels and the Winkel tongue coating index. Standard periodontal outcome variables were assessed at six teeth. Standardized microbiological samples of subgingival plaque, unstimulated saliva, and tongue coating were obtained for culture analysis. The treatment protocol included supragingival prophylaxis; instructions in oral hygiene (toothbrushing, interproximal cleaning, and tongue scraping); and gargling with a mouthrinse containing chlorhexidine, cetylpiridinium chloride, and zinc lactate. The same outcome variables were registered 1 and 3 months after baseline. RESULTS: Statistically significant reductions in organoleptic scores (P <0.001), VSC levels (P <0.05), and tongue coating index (P <0.05) were observed after 1 and 3 months. Mean probing depth and plaque levels also demonstrated significant reductions after 3 months (P <0.05). Total anaerobic counts were significantly reduced at all three locations after 1 month (P <0.05), and in samples from tongue coating and subgingival plaque at 3 months (P <0.05). Aerobic counts were significantly reduced in saliva at 1 month (P <0.05), and the anaerobic/aerobic ratio significantly increased in the tongue samples. Among the selected pathogens evaluated, Porphyromonas gingivalis was the most affected of the three microflora evaluated. CONCLUSIONS: The evaluated therapeutic approach demonstrated its efficacy in the management of oral halitosis, demonstrating statistically significant improvements in both organoleptic and VSC values at 1 and 3 months. The proposed clinical protocol significantly affected the microbial composition in tongue coating, saliva, and subgingival microflora.

Adult↗
PubMed1986

Studies on the spin-spin interaction between flavin and iron-sulfur cluster in an iron-sulfur flavoprotein.

When the di- or trimethylamine dehydrogenases (trimethylamine:(acceptor) oxidoreductase (demethylating), EC 1.5.99.7) of certain methylotrophic bacteria are reduced by two electrons with substrate unusual EPR signals arise at g = 2 and g = 4 (Steenkamp, D.J. and Beinert, H. (1982) Biochem. J. 207, 233-239; 241-252) indicative of spin-spin interaction between the FMN and iron-sulfur compounds of these enzymes. An attempt is made to understand, describe and simulate these spectra in terms of a triplet state with possible contributions from both dipolar and anisotropic exchange (J) interactions. No direct measurement of J is available, but various approaches to setting limits to J are outlined. According to these, J approximately 0.4 to 3 cm-1 or 15 to 50 cm-1. The spectra show, in the g = 2 region, a pair of rather sharp inner and a pair of broad outer lines; the latter broaden as well as move out from the center with increasing time (after substrate addition) and substrate concentration, while there is little change of g = 4. The best fits to such spectra were obtained by assuming distribution of D and E values, depending on substrate effects and arriving presumably from 'g-strain'. The fact that both shapes and intensities at g = 2 and g = 4 could be reproduced simultaneously at two frequencies indicates that the assumptions underlying our approaches and interpretations are permissible and reasonable, although we cannot claim their uniqueness. The distance between the centers of the spin densities of the flavin radical and the Fe-S cluster is thought to lie between the limits 3 to 5 A if the asymmetries in the spin-spin interaction are magnetic dipole-dipole in origin. Because there is an indication that the interaction is anisotropic exchange, the upper limit is less stringent.

Bacteria↗
PubMed2004

Food safety and epidemiology: new database of functional food factors.

More than 600 functional non-nutrient food factors (FFFs) in vegetables and fruits are considered to be effective for health promotion and disease prevention. However, phytochemicals studied thus far have failed to yield predicted results in randomized intervention studies. To assess the health effects of phytochemicals, a breakthrough in epidemiological methods was necessary. We constructed a database of non-nutrient FFFs to estimate the chemical classes and total amount of FFF-intake in order to facilitate estimation and calculation for nutritional research. So far, flavonoids, terpenoids, carotenoids, and sulfur compounds are included in our FFF database. We calculated the intake of various phytochemicals per capita from 79 subjects' dietary records by FFF database, and estimated that subjects ingested more than 10 micromole per day of phytochemicals such as catechin, isoflavones, isothiocyanate, ferulic acid, quercetin, cinnamic acid and chlorogenic acid. Chief component analysis yielded 12 factors (80%), of which only a few factors showed negative associations with serum cholesterol and LDL concentration. Many factors showed adverse relationships with liver function and serum triacylglycerol concentration. Weekly self-reported daily dietary records including name of dish, constituent foods and their amounts were separately collected for 6 months and analyzed in Kyoto women. Seasonal changes of phytochemical intake showed significant variation according to the seasonal consumption of fruits and vegetables. Lycopene increased in the summer due to watermelon and tomato intake in this season. Seasonal variation of FFF was quite large compared to the variation of macro- and micronutrients. Careful evaluation of the effects of FFF intake on health is necessary, especially when supplements are also consumed. The most effective combinations of FFF intake for human health could be elucidated by using our FFF-DB in conjunction with population-based cohort studies.

Carotenoids↗
PubMed2004

The construction of web database server-client system for functional food factors.

In food, other than known nutrients, such as lipid, carbohydrate, protein, vitamins, and minerals, many substances with physiological function and medicinal action exist, and it is contributing to healthy improvement and/or prevention of illness. Although carotenoid, flavonoid and polyphenol, terpenoid, volatile substance and sulfur compounds, peptide, etc. have the function of illness prevention, and research of those non-nutrient functional food factors (FFF) became globally active, the research of this field is not yet done systematically. We evaluate function of FFF and reappraise known knowledge, and this knowledge is standardized and accumulated, aimed at building a web database server-client system which is easy to use for the people and nutritional research. We also collected related data such as chemical characters of FFF from literatures and other source, and formatted them into the database. We constructed the web database server-client system with MySQL database server and Apache web server based on Linux, and used Tomcat JSP engine for data connecting since they were reliable in stability and speed. We are opening the database at http://www.life-science.jp/FFF for test now.

Database Management Systems↗
PubMed2004

3-Methyl-3-sulfanylhexan-1-ol as a major descriptor for the human axilla-sweat odour profile.

This study sets out to redress the lack of knowledge in the area of volatile sulfur compounds (VSCs) in axillary sweat malodour. Sterile odourless underarm sweat (500 ml) was collected from 30 male volunteers after excessive sweating. Five strains of bacteria, Corynebacterium tuberculostearicum, Corynebacterium minutissimum, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Bacillus licheniformis, were isolated and characterised for their ability to generate an authentic axillary odour from the sweat material collected. As expected, all of the five bacterial strains produced strong sweat odours. Surprisingly, after extensive olfactive evaluation, the strain of Staphylococcus haemolyticus produced the most sulfury sweat character. This strain was then chosen as the change agent for the 500 ml of odourless underarm sweat collected. After bacterial incubation, the 500-ml sample was further processed for GC-olfactometry (GC-O), GC/MS analysis. GC-O of an extract free of organic acids provided three zones of interest. The first was chicken-sulfury, the second zone was onion-like, and the third zone was sweat, clary sage-like. From the third zone, a new impact molecule, (R)- or (S)-3-methyl-3-sulfanylhexan-1-ol, was isolated and identified by GC/MS, MD-GC, and GC AED (atomic emission detector). (S)-3-methyl-3-sulfanylhexan-1-ol was sniff-evaluated upon elution from a chiral GC column and was described as sweat and onion-like; its opposite enantiomer, (R)-3-methyl-3-sulfanylhexan-1-ol, was described as fruity and grapefruit-like. The (S)-form was found to be the major enantiomer (75%).

Adult↗
PubMed2005

Identification of the precursor of (S)-3-methyl-3-sulfanylhexan-1-ol, the sulfury malodour of human axilla sweat.

A careful study of human axillary microflora led us to the identification of a new strain of Staphylococcus haemolyticus. The role in axillary malodour formation of this microorganism was compared to those of Corynebacterium xerosis and Staphylococcus epidermidis, upon incubation on sterile human eccrine and apocrine axilla sweat. St. haemolyticus was responsible for the strongest sulfury malodour and the generation of the volatile sulfur compound (VSC) (S)-3-methyl-3-sulfanylhexan-1-ol (3). In this study, we investigated the nonvolatile precursors of VSCs. Human axillary sweat was collected, fractionated and analysed by HPLC/APCI-MS (High-Pressure Liquid Chromatography coupled to Atmospheric Pressure Chemical Ionisation Mass Spectrometry). The precursor of 3 was identified as [1-(2-hydroxyethyl)-1-methylbutyl]-L-cysteinylglycine (Cys-Gly-(S)-conjugate; 12). Because Cys-Gly-(S)-conjugates are key intermediates in the glutathione biodetoxification pathway, other derivatives of 12, specifically glutathione-(S)-conjugate 11 and Cys-(S)-conjugate 13, were prepared. Compounds 11 and 13 were not detected by HPLC/MS of sterile sweat. Synthetic homologues 11, 12, and 13 were incubated with C. xerosis, St. heamolyticus, and St. epidermidis. We observed efficient conversion of precursors 12 and 13 to form VSCs when incubated with St. haemolyticus, with a clear preference for 12. C. xerosis and St. epidermidis were less efficient in cleaving Cys-Gly-(S)-conjugate 12 to form the corresponding thiol 3. Incubation of glutathione-(S)-conjugate 11 never led to the formation of 3 under the experimental conditions employed.

Axilla↗
PubMed2006

Chiral multidimensional gas chromatography (MDGC) and chiral GC-olfactometry with a double-cool-strand interface: application to malodors.

Volatile sulfur compounds such as 3-methyl-3-sulfanylhexan-1-ol (1) are largely responsible for axillary-sweat malodors. In this work, we describe the determination of the enantiomer ratio of the trace constituent 1 and the odor description of its antipodes (R)- and (S)-1 by means of multidimensional gas chromatography (MDGC) in combination with chiral gas chromatography-olfactometry (GC-O). This technique allowed the on-line evaluation of the sensory character of both enantiomers via a sniffing port, and is based on a novel double-cool-strand interface (DCSI). First, the system's inertness was tested towards the labile compound 2-methylfuran-3-thiol (MFT; 2). Then, the DCSI was used in a new configuration to achieve olfactive characterization by means of chiral GC-O. In contrast to direct smelling after the chiral column, our technique allows, for the first time, to significantly delay the perception of the second-eluting enantiomer after the first one. This lowers the risk of sensory saturation, as the panelist can recover from the first stimulus, before evaluating the second one. To help programming the DCSI, a dedicated program was set up. The enantiomer ratio of the sweat malodor 1 was determined as (S)/(R) 3 : 1, and the dominating (S)-isomer was shown to largely impart its specific character to the overall odor of the sweat extract.

Cold Temperature↗
PubMed1990

Methanethiol metabolism and its role in the pathogenesis of hepatic encephalopathy in rats and dogs.

The metabolism of methanethiol was studied in rats. Administration of a noncomatogenic dose of methanethiol through inspired air or injection into the upper colon resulted in an elevation of the concentrations of methanethiol mixed disulfides in serum (protein--S--S--CH3 and X--S--S--CH3, X yet unknown) and in urine (X--S--S--CH3). The concentrations of methanethiol mixed disulfides proved to be a relative measure of exposure to methanethiol. The levels of volatile sulfur compounds methanethiol, dimethylsulfide and dimethyldisulfide in the air expired by rats exposed to a noncomatogenic dose of methanethiol through the colon were also elevated. Rats with acute hepatic encephalopathy caused by liver ischemia also showed elevation of methanethiol mixed disulfide levels on challenge of methanethiol through the colon or inspired air, but to a significantly smaller extent than did the corresponding sham-operated rats. This suggests that the liver is at least partly responsible for formation of methanethiol mixed disulfides. No additional toxic effects were observed in the rats with ischemic livers on methanethiol exposition when compared with normal rats, suggesting that the liver does not play an essential role in methanethiol detoxification. Metabolism of methanethiol by blood to sulfate, for example, might be more important. In rats with acute hepatic encephalopathy caused by liver ischemia and in dogs suffering from hepatic encephalopathy resulting from chronic liver disease, large and significant increases in ammonia levels were measured. However, the mean levels of methanethiol mixed disulfides in rats and dogs with hepatic encephalopathy were not different from the mean normal levels in these animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1979

[Oxidative degradation of dibenzylsulfide].

Dibenzylsulfid (DBS) as a model of the organic sulfur compounds in crude oil was converted by a mixed culture (containing Pseudomonas aeruginosa) into several water soluble organic substances. Whereas these compounds are detectable with DC- and IR-spectroscopic techniques, benzylmercaptoacetic acid (BMA) was the only isolated product of DBS utilization. Efficiency of degradation, respectively, accumulation of BMA were dependent on aeration and pH-regulation.

Acetates↗
PubMed1996

Covalent structure of the flavoprotein subunit of the flavocytochrome c: sulfide dehydrogenase from the purple phototrophic bacterium Chromatium vinosum.

The amino acid sequence of the flavoprotein subunit of Chromatium vinosum flavocytochrome c-sulfide dehydrogenase (FCSD) was determined by automated Edman degradation and mass spectrometry in conjunction with the three-dimensional structure determination (Chen Z et al., 1994, Science 266:430-432). The sequence of the diheme cytochrome c subunit was determined previously. The flavoprotein contains 401 residues and has a calculated protein mass, including FAD, of 43,568 Da, compared with a mass of 43,652 +/- 44 Da measured by LDMS. There are six cysteine residues, among which Cys 42 provides the site of covalent attachment of the FAD. Cys 161 and Cys 337 form a disulfide bond adjacent to the FAD. The flavoprotein subunit of FCSD is most closely related to glutathione reductase (GR) in three-dimensional structure and, like that protein, contains three domains. However, approximately 20 insertions and deletions are necessary for alignment and the overall identity in sequence is not significantly greater than for random comparisons. The first domain binds FAD in both proteins. Domain 2 of GR is the site of NADP binding, but has an unknown role in FCSD. We postulate that it is the binding site for a cofactor involved in oxidation of reduced sulfur compounds. Domains 1 and 2 of FCSD, as of GR, are homologous to one another and represent an ancient gene doubling. The third domain provides the dimerization interface for GR, but is the site of binding of the cytochrome subunit in FCSD. The four functional entities, predicted to be near the FAD from earlier studies of the kinetics of sulfite adduct formation and decay, have now been identified from the three-dimensional structure and the sequence as Cys 161/Cys 337 disulfide, Trp 391, Glu 167, and the positive end of a helix dipole.

Amino Acid Sequence↗
PubMed2000

On the irreversible destruction of reduced nicotinamide nucleotides by hypohalous acids.

Degradation of the reduced pyridine nucleotides NMNH and NADH by HOCl involves two distinct stages: a fast reaction, k = 4.2 x 10(5) M(-1) s(-1), leads to generation of stable pyridine products (Py/Cl) with a strong absorption band at 275 nm (epsilon = 12.4 x 10(3) M(-1) cm(-1) in the case of NMNH); secondarily, a subsequent reaction of HOCl, k = 3.9 x 10(3) M(-1) s(-1), leads to a complete loss of the aromatic absorption band of the pyridine ring. HOBr and HOI(I(2)) react similarly. Apparent rate constants of the primary reactions of HOX species with NMNH at pH 7.2 increase in the order HOCl (3 x 10(5) M(-1) s(-1)) < HOBr( approximately 4 x 10(6) M(-1) s(-1)) < HOI(I(2))( approximately 6.5 x 10(7) M(-1) s(-1)). HOBr reacts fast also with the primary product Py/Br, k approximately 9 x 10(5) M(-1) s(-1), while the reactions of HOI and I(2) with Py/I are slower, approximately 1.4 x 10(3) M(-1) s(-1) and >6 x 10(3) M(-1) s(-1), respectively. Halogenation of the amide group of NMN(+) by HOX species is many orders of magnitude slower than oxidation of NMNH. Taurine inhibits HOCl-induced oxidation of NADH, but HOBr-induced oxidation is not inhibited because the taurine monobromamine rapidly oxidizes NADH, and oxidation by HOI(I(2)) is not inhibited because taurine is inert toward HOI(I(2)). Also sulfur compounds (GSH, GSSG, and methionine) are less efficient in protecting NADH against oxidation by HOBr and HOI(I(2)) than against oxidation by HOCl. The results suggest that reactions of HOBr and HOI(I(2)) in a cellular environment are much more selectively directed toward irreversible oxidation of NADH than reactions of HOCl. It is noteworthy that the rather inert N-chloramines react with iodide to generate HOI(I(2)), i.e., the most reactive and selective oxidant of reduced pyridine nucleotides. NMR investigations show that the primary stable products of the reaction between NMNH and HOCl are various isomeric chlorohydrins originating from a nonstereospecific electrophilic addition of HOCl to the C5&dbond;C6 double bond of the pyridine ring. The primary products (Py/X) of NMNH all exhibit similar absorption bands around 275 nm and are hence likely to result from analogous addition of HOX to the C5&dbond;C6 bond of the pyridine ring. Since the Py/X species are stable and inert toward endogeneous reductants like ascorbate and GSH, they may generally be useful markers for assessing the contribution of hypohalous acids to inflammatory injury.

Bromates↗
PubMed1995

Malate metabolism by Desulfovibrio gigas and its link to sulfate and fumarate reduction: purification of the malic enzyme and detection of NAD(P)+ transhydrogenase activity.

Malate metabolism was investigated in lactate grown cells of Desulfovibrio gigas ; 3 mol of malate are converted into 2 mol succinate and 1 mol acetate. The malic enzyme (L-malate:NADP+ oxidoreductase) was purified to homogeneity and partially characterized. The enzyme is monomeric with molecular weight of 45 kDa. Its spectrum has no visible absorption and the activity is stimulated by K+ and Mg2+. The presence of an NAD(P)+ transhydrogenase, the observation of partial reduction of adenylylsulfate reductase by NADH (via NADH-rubredoxin oxidoreductase) and evidence for NADH-linked fumarate reductase activity support the involvement of pyridine nucleotides in the electron pathway toward the reduction of sulfur compounds and/or fumarate. An electron transfer chain to fumarate is proposed, taking into consideration these results and the stoichiometry of end-products derived from malate dismutation.

Journal Article↗
PubMed2000

Methylene blue photosensitized oxidation of cysteine sulfinic acid and other sulfinates: the involvement of singlet oxygen and the azide paradox.

The methylene blue photosensitized oxidation of cysteine sulfinic acid is investigated. Enhancement of the oxygen consumption rate in deuterium oxide suggests the involvement of singlet oxygen ((1)O(2)) in oxidation. Addition of the (1)O(2) quencher azide produced an unusual enhancement of the oxidation rate of all the sulfinates assayed. It is assumed that azide works as a one-electron carrier between (1)O(2) and the sulfur compounds. Analyses of the products indicate that the photochemical oxidation of cysteine sulfinic acid proceeds through two simultaneous mechanisms. The Type II (singlet oxygen) mechanism is responsible for oxidation of the sulfinic group to the sulfonic group with production of cysteic acid, stable to the photooxidation system, whereas the Type I (electron transfer) mechanism is involved in the degradation of cysteine sulfinic acid to acetaldehyde. Other products detected were ammonia, sulfate, and hydrogen peroxide which account for the degradation of cysteine sulfinic acid and for the excess of oxygen consumption detected during the oxidative reaction.

Aerobiosis↗