Genetic characteristics of cellulose-forming acetic acid bacteria identified phenotypically as Gluconacetobacter xylinus. (41/1272)

Gluconacetobacter xylinus (=Acetobacter xylinum) shows variety in acid formation from sugars and sugar-alcohols. Toyosaki et al. proposed new subspecies of G. xylinus (=Acetobacter xylinum) subsp. sucrofermentans in point of acid formation from sucrose and a homology index of 58.2% with the type strain of G. xylinus subsp. xylinus in DNA-DNA hybridization experiments. We tried DNA-DNA hybridization to clarify relationship between acid formation from sugars and classification of G. xylinus. The G + C contents of G. xylinus showed 60.1-62.4 mol% with a range of 2.3 mol%. When type strains of G. xylinus subsp. xylinus, G. xylinus subsp. sucrofermentans, and IFO 3288 forming acid from sucrose, were used as probes, the DNAs from three strains showed 67-100%, 64-89%, and 60-100% similarity to those from sixteen strains including bacteria that form acid from sucrose or not. These results show that homology indexes do not reflect differences of acid formation from sucrose. As a results, the species G. xylinus was proved to be genetically homogeneous.  (+info)

Possible involvement of aminotelopeptide in self-assembly and thermal stability of collagen I as revealed by its removal with proteases. (42/1272)

The functions of aminotelopeptide and N-terminal cross-linking of collagen I were examined. Acetic acid-soluble collagen I (ASC) was purified from neonatal bovine skin and treated with three kinds of proteases. The amino acid sequencing analysis of the N terminus showed that ASC contained a full-length aminotelopeptide. Pepsin and papain cleaved the aminotelopeptide of the alpha1 chain at the same site and the aminotelopeptide of the alpha2 chain at different sites. Proctase-treated ASC lost the whole aminotelopeptide, and the N-terminal sequence began from the tenth residue inside the triple helical region. The rates of fibril formation of pepsin-treated ASC and proctase-treated ASC were the same and were slower than that of ASC. The denaturation temperatures, monitored by CD ellipticity at 221 nm, of ASC, pepsin-treated, or papain-treated collagens were the same at 41.8 degrees C. Proctase-treated ASC showed a lower denaturation temperature of 39.9 degrees C. We also observed the morphology of the collagen fibrils under an electron microscope. The ASC fibrils were straight and thin, whereas the fibrils of pepsin-treated ASC were slightly twisted, and the fibrils from papain- and proctase-treated ASC were highly twisted and thick. When the collagen gel strength was examined by a modified method of viscosity-measurement, ASC was the strongest, followed by pepsin-treated ASC, and papain- and proctase-treated ASCs were the weakest. These results suggest that the aminotelopeptide plays important roles in fibril formation and thermal stability. In addition, the functions of intermolecular cross-linking in aminotelopeptides may contribute to the formation of fibrils in the correct staggered pattern and to strengthening the collagen gel.  (+info)

In vitro fermentation pattern of D-tagatose is affected by adaptation of the microbiota from the gastrointestinal tract of pigs. (43/1272)

Knowledge of the fermentation pattern of D-tagatose is important for the assessment of energy value and compliance of D-tagatose. In vitro fermentation experiments with pig intestinal contents and bacteria harvested from the gastrointestinal tract of pigs were used to investigate the degradation of D-tagatose and the formation of fermentation products. Two groups of eight pigs were fed either a control diet containing 150 g/kg sucrose or a diet which had 100 g/kg of the sucrose replaced by D-tagatose. After 18 d the pigs were killed and the gastrointestinal contents collected for in vitro studies. No microbial fermentation of D-tagatose occurred in the stomach or in the small intestine, whereas the sugar was fermented in the cecum and colon. Formate, acetate, propionate, butyrate, valerate, caproate and some heptanoate were produced by the microbial fermentation of D-tagatose by gut microbiota. Hydrogen and methane were also produced. The population of D-tagatose-degrading bacteria in fecal samples and the capacity of bacteria from the hindgut to degrade D-tagatose were higher in the pigs adapted to D-tagatose compared with unadapted pigs. In unadapted pigs, the major fermentation product from D-tagatose was acetic acid. Much more butyric and valeric acids were produced from D-tagatose by bacterial slurries of tagatose-adapted pigs compared with unadapted pigs; this was especially the case for samples from the colon. We conclude that D-tagatose is not fermented in the upper gastrointestinal tract, and the ability of the large intestinal microbiota to ferment D-tagatose is dependent on adaptation.  (+info)

Cytokine-mediated inflammatory hyperalgesia limited by interleukin-1 receptor antagonist. (44/1272)

1. The effect of IL-1ra on response to intraplantar (i.pl.) injection of LPS, carrageenin, bradykinin, TNFalpha, IL-1beta, IL-8, PGE(2) and dopamine was investigated in a model of mechanical hyperalgesia in rats. 2. IL-1ra inhibited hyperalgesic response to LPS, carrageenin, bradykinin, TNFalpha, and IL-1beta, but not responses to IL-8, PGE(2) and dopamine. 3. A sheep anti-rat IL-1ra serum potentiated response to LPS, carrageenin, bradykinin, TNFalpha and IL-1beta but not IL-8. 4. Carrageenin and LPS stimulated and production of immunoreactive TNFalpha, IL-1beta and IL-1ra in the skin of injected paws. 5. The inhibition by IL-1ra of the hyperalgesic response to carrageenin was not affected by antibodies neutralizing IL-4 and IL-10. 6. In mice, IL-1ra inhibited the nociceptive response to i.p. injection of acetic acid. 7. These data suggest that IL-1ra, released at sites of inflammation, limits inflammatory hyperalgesia. This effect is independent of (IL-1ra-induced) IL-4 and IL-10 and appears to be the result of antagonism by IL-1ra of IL-1beta-stimulated eicosanoid production.  (+info)

Metabolic pathways for cytotoxic end product formation from glutamate- and aspartate-containing peptides by Porphyromonas gingivalis. (45/1272)

Metabolic pathways involved in the formation of cytotoxic end products by Porphyromonas gingivalis were studied. The washed cells of P. gingivalis ATCC 33277 utilized peptides but not single amino acids. Since glutamate and aspartate moieties in the peptides were consumed most intensively, a dipeptide of glutamate or aspartate was then tested as a metabolic substrate of P. gingivalis. P. gingivalis cells metabolized glutamylglutamate to butyrate, propionate, acetate, and ammonia, and they metabolized aspartylaspartate to butyrate, succinate, acetate, and ammonia. Based on the detection of metabolic enzymes in the cell extracts and stoichiometric calculations (carbon recovery and oxidation/reduction ratio) during dipeptide degradation, the following metabolic pathways were proposed. Incorporated glutamylglutamate and aspartylaspartate are hydrolyzed to glutamate and aspartate, respectively, by dipeptidase. Glutamate is deaminated and oxidized to succinyl-coenzyme A (CoA) by glutamate dehydrogenase and 2-oxoglutarate oxidoreductase. Aspartate is deaminated into fumarate by aspartate ammonia-lyase and then reduced to succinyl-CoA by fumarate reductase and acyl-CoA:acetate CoA-transferase or oxidized to acetyl-CoA by a sequential reaction of fumarase, malate dehydrogenase, oxaloacetate decarboxylase, and pyruvate oxidoreductase. The succinyl-CoA is reduced to butyryl-CoA by a series of enzymes, including succinate-semialdehyde dehydrogenase, 4-hydroxybutyrate dehydrogenase, and butyryl-CoA oxidoreductase. A part of succinyl-CoA could be converted to propionyl-CoA through the reactions initiated by methylmalonyl-CoA mutase. The butyryl- and propionyl-CoAs thus formed could then be converted into acetyl-CoA by acyl-CoA:acetate CoA-transferase with the formation of corresponding cytotoxic end products, butyrate and propionate. The formed acetyl-CoA could then be metabolized further to acetate.  (+info)

CT-Guided acetic acid injection therapy for aldosterone-producing adrenocortical adenoma: a preliminary report of three cases. (46/1272)

We reported the preliminary outcomes of CT-guided percutaneous injection therapy for aldosterone-producing adrenocortical adenoma (APA). Five sessions of injection therapy, 4 percutaneous acetic acid injections (PAI) and 1 percutaneous ethanol injection (PEI) were performed in 3 patients with APA. A small amount of acetic acid or ethanol solution was injected via a needle placed precisely inside the tumor. The procedure was frequently monitored by repetitive CT scanning. The follow-up period ranged from 5 to 27 months. After the treatment, hypertension was normalized or controlled by a low dose of conventional anti-hypertensive drug. In 2 of 3 cases the plasma aldosterone levels were normalized. Although temporary symptoms of alcoholic intoxication were observed in the single session of PEI, the 4 sessions of PAI were associated with no adverse symptoms or complications. Although this study covers only short-term results in 3 patients, CT-guided PAI appears to be a safe and effective treatment and may be a promising alternative as a simple and far less invasive therapy for APA.  (+info)

Effect of polaprezinc on healing of acetic acid-induced stomatitis in hamsters. (47/1272)

PURPOSE: The purpose of this work was to investigate the potential effectiveness of polaprezinc in the treatment of stomatitis. Its effect on oral mucous membrane lesions was studied focusing on acetic acid-induced stomatitis in an animal model. METHOD: Stomatitis was induced in hamsters by local injection of 30 microL of 10% acetic acid solution into both cheek pouches. Change of the size of the acetic acid-induced white lesion caused by polaprezinc injection was compared with that of control (water injection). The process of healing of damaged membrane was also investigated histopathologically. Selective adhesion of polaprezinc on mucous membrane was studied using color development by complexation between zinc and dithizone. RESULTS: On day 4 after acetic acid injection, round white lesions were observed in the central area of both pouches. Observation on days 7, 10, and 14 showed that the size of the lesions decreased with time. Comparison with the control group of animals, in which healing took place naturally, showed that daily administration of polaprezinc (10 mg/kg) applied to the cheek pouches significantly promoted healing of the lesion from day 7 onward. Histopathological investigation of the mucous membrane in the cheek pouches 7 days after the induction of stomatitis by acetic acid injection showed thickening, and cell damage was evident. In the group of animals treated with polaprezinc, the thickening of the mucous membrane was less than that in animals of the group receiving no treatment and regeneration of damaged tissue was observed after 6 days of polaprezinc treatment. CONCLUSION: Polaprezinc is an effective treatment in this animal model of acetic acid-induced stomatitis. This suggests that the drug may be useful in promoting healing of stomatitis in the clinical setting. Extrapolating these to humans suggests that the drug has healing effect to severe stomatitis induced by anticancer drug therapy.  (+info)

Antibacterial activity of chaff vinegar and its practical application. (48/1272)

Since enterohemorrhagic Escherichia coli O157, Salmonella, etc., sometimes contaminate animal feces and may cause infectious diseases to humans, it is important to remove pathogenic bacteria from domestic animal waste. For the purpose, we examined the antibacterial activity of chaff vinegar. We found that the chaff vinegar inhibited the growth of pathogenic bacteria immediately in vitro but not efficiently spores and lactic acid bacteria. Further, it removes bacteria, especially Enterobacteriaceae, from animal feces and the surface of the concrete-floor in the cattle barn. Chaff vinegar is advertised as a natural chemical substance for a soil conditioner, to promote the composting and to deodorize their smell. Chaff vinegar may be useful for organic agriculture without enteric pathogenic bacteria.  (+info)