Inhibitory effects of Oenothera biennis (evening primrose) seed extract on Streptococcus mutans and S. mutans-induced dental caries in rats.

BACKGROUND: Oenothera biennis (evening primrose) seed extract (OBSE) is known to contain polyphenols, which may possess antioxidant activities. Polyphenols extracted from several plants are reported to exhibit cariostatic activities by inhibiting mutans streptococcus growth and glucosyltransferase activities. The purpose of the present study was to examine the inhibitory effects of OBSE on the development of dental caries, both in vitro and in vivo. METHODS: OBSE was investigated for its inhibitory effects on cellular aggregation, hydrophobicity, sucrose-dependent adherence and insoluble glucan synthesis. Furthermore, biofilm formation was examined in the presence of OBSE, using confocal microscopic imaging. An animal experiment was also performed to examine the in vivo effects. RESULTS: OBSE induced a strong aggregation of Streptococcus mutans MT8148 cells, while cell surface hydrophobicity was decreased by approximately 90% at a concentration of 0.25 mg/ml. The sucrose-dependent adherence of the MT8148 cells was also reduced by addition of OBSE, with a reduction rate of 73% seen at a concentration of 1.00 mg/ml. Additionally, confocal microscopic observations revealed the biofilm development phase to be remarkably changed in the presence of OBSE. Furthermore, insoluble glucan synthesis was significantly reduced when OBSE was present at concentrations greater than 0.03 mg/ml. In an animal experiment, the caries scores in rats given OBSE (0.05 mg/ml in drinking water) were significantly lower than those in rats given water without OBSE. CONCLUSION: Our results indicate that OBSE has inhibitory activity on dental caries.

Antimicrobial susceptibility of Propionibacterium acnes isolated from acne vulgaris.

Systemic and topical antimicrobial treatment for acne vulgaris remains the mainstay method of therapy in Japan. Strains of Propionibacterium acnes (P. acnes) resistant to erythromycin (EM), clindamycin (CLDM), tetracycline (TC), doxycycline (DOXY) and minocycline (MINO) have been reported. The aim of the present study was to examine the antimicrobial susceptibility to 10 currently used antimicrobial agents of 50 strains of P. acnes isolated from acne lesions and identified using a Rap ID ANA II panel. Minimum inhibitory concentrations (MIC) were determined by the agar dilution method according to the criteria of the Japan Society of Chemotherapy. EM, ampicillin (ABPC), and CLDM were the most potent drugs, followed by MINO, nadifloxacin (NDFX), cephalexin (CEX), DOXY, ofloxacin (OFLX), and TC. In terms of the MIC80, EM and ABPC were the most potent, followed by CLDM, NDFX, MINO, CEX, DOXY, OFLX, TC and gentamycin (GM). Although most of the strains used were susceptible to the antimicrobial agents tested, strains of P. acnes resistant (MIC 12.5 mug/ml) to EM (4%), CLDM (4%), DOXY (2%) and TC (2%) were observed. In this study, no strains of P. acnes resistant to MINO were seen, suggesting that oral MINO is the most useful treatment for acne vulgaris with minimal risk of bacterial resistance.

Sensitivity to antibacterials of Staphylococcus aureus isolated from skin infections: a comparison of two hospitals.

We compared the sensitivities to antibacterials of Staphylococcus aureus strains isolated from skin infections in two hospitals of different sizes. There were differences between the two hospitals in the proportions of the strains isolated that were resistant to certain drugs, and these differences may be related to the patterns of drug use at each hospital. The differences in the patterns of drug use at each hospital may be due to the types of infections encountered and/or the ages of the patients, both of which differed greatly. The proportions of resistant strains may also be related to differences in the proportions of in-patients.

Sensitivity to antibacterials of Staphylococcus aureus isolated from different types of skin infections.

We examined the antibacterial susceptibility of Staphylococcus aureus isolated from several types of skin infections, which were classified into four groups: (i) impetigo, (ii) folliculitis, (iii) atopic dermatitis and eczema and (iv) ulcers and decubitus. The 50% minimal inhibitory concentration (MIC50) of the antibacterial agents was 3.13 micrograms/ml or lower, except that of gentamicin with isolates from the impetigo groups (25 micrograms/ml). The MIC90 of gentamicin was 50 micrograms/ml or more for isolates from all four groups. The isolates from the ulcers and decubitus group showed multiple resistance against antibacterial agents. The frequency of methicillin-resistant S. aureus was low, but was highest, at 25%, in the isolates from the ulcers and decubitus group. Few isolates from the atopic dermatitis and eczema group were resistant, and there was little difference in antibacterial resistance between isolates from atopic dermatitis and eczema.

Nucleotide sequence of the cDNA encoding the proenzyme of phenol oxidase A1 of Drosophila melanogaster.

Clones encoding pro-phenol oxidase [pro-PO; zymogen of phenol oxidase (monophenol, L-dopa:oxygen oxidoreductase, EC 1.14.18.1)] A1 were isolated from a lambda gt10 library that originated from Drosophila melanogaster strain Oregon-R male adults. The 2294 bp of the cDNA included a 13-bp 5'-noncoding region, a 2070-bp encoding open reading frame of 690 amino acids, and a 211-bp 3'-noncoding region. A hydrophobic NH2-terminal sequence for a signal peptide is absent in the protein. Furthermore, there are six potential N-glycosylation sites in the sequence, but no amino sugar was detected in the purified protein by amino acid analysis, indicating the lack of an N-linked sugar chain. The potential copper-binding sites, amino acids 200-248 and 359-414, are highly homologous to the corresponding sites of hemocyanin of the tarantula Eurypelma californicum, the horseshoe crab Limulus polyphemus, and the spiny lobster Panulirus interruptus. On the basis of the phylogenetic tree constructed by the neighbor-joining method, vertebrate tyrosinases and molluscan hemocyanins constitute one family, whereas pro-POs and arthropod hemocyanins group with another family. It seems, therefore, likely that pro-PO originates from a common ancestor with arthropod hemocyanins, independently to the vertebrate and microbial tyrosinases.

cDNA cloning and deduced amino acid sequence of prothrombin activator (ecarin) from Kenyan Echis carinatus venom.

The complete amino acid sequence of ecarin is deduced from the nucleotide sequence of a cDNA clone isolated by screening a venomous gland cDNA library of Kenyan Echis carinatus. The cDNA sequence with 2379 base pairs encodes an open reading frame of 616 amino acids with a remarkable sequence homology to the putative precursor protein of trigramin from Trimeresurus gramineus venom (61% identity) and a large hemorrhagin, jararhagin, from the pit viper Bothrops jararaca venom (62% identity). Thus, ecarin, as well as jararhagin and trigramin, is translated as a precursor protein, which may be processed posttranslationally. The ecarin proprotein has a "cysteine switch" motif (-Pro-Lys-Met-Cys-Gly-Val-) similar to that involved in the activation of matrix metalloproteinase zymogens. The processed mature protein consists of 426 amino acid residues (residues 191-616), showing the strongest sequence similarity with that of Russell's viper venom factor X activator (RVV-X) heavy chain (64% identity). Like RVV-X heavy chain, ecarin contains metalloproteinase, disintegrin, and cysteine-rich domains. The metalloproteinase domain has a typical zinc-chelating sequence (-His-Glu-Xaa-Xaa-His-Xaa-Xaa-Gly-Xaa-Xaa-His-), as found in crayfish astacin. In the disintegrin domain of ecarin, the Arg-Gly-Asp sequence is replaced by Arg-Asp-Asp, as found in the disintegrin domains of RVV-X heavy chain (Arg-Asp-Glu) and a guinea pig sperm fusion protein, PH-30 beta (Thr-Asp-Glu). These findings show that while there are structural and evolutionary relationships among these proteins, each has a unique functional activity.

Expression of the rat arginine vasopressin gene in transgenic mice.

A line of mice has been developed which are transgenic for an 8.2-kilobase (kb) genomic clone of the rat vasopressin (VP) gene. Using a polymerase chain reaction technique, the rat VP (rVP) transgene was shown to have tissue-specific mRNA expression in the hypothalamus, temporal lobe, parietal cerebral cortex, cerebellum, and posterior pituitary, similar to the tissue distribution of endogenous mouse and rat VP expression. Expression of transgenic rVP mRNA was also found in the lung and pancreas of the transgenic mice, sites of known ectopic expression of VP. Using two methods, Northern blot analysis with species-specific cRNA probes and a quantitative polymerase chain reaction technique, the quantity of rVP transgene mRNA was shown to regulate appropriately in response to an osmotic stimulus. After 72 h of water deprivation, the quantity of transgenic rVP mRNA increased 6.8 +/- 3.0-fold. This was not significantly different than the fold increase in mouse VP mRNA quantity seen in nontransgenic mice (4.8 +/- 1.5) but was significantly different (P < 0.05) than the 1.2 +/- 0.03-fold increase in rat VP mRNA seen in normal rats after water deprivation. In the rat hypothalamus, VP mRNA poly(A) tail length increases with osmotic stimulation, while in the mouse it does not. The poly(A) tail of transgenic rVP mRNA expressed in mouse hypothalamus did not increase in length after osmotic stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased vasopressin secretion and release in mice transgenic for the rat arginine vasopressin gene.

The rat arginine vasopressin (AVP) genomic sequence has been utilized to develop a line of transgenic mice homozygous and heterozygous for the transgene. Expression of the rat AVP gene was demonstrated by Southern blotting and resulted in increased amounts of AVP in hypothalamus and frontotemporal brain cortex. Secretion of AVP from the neurohypophysial system results in an increased concentration of the hormone in the plasma and in an increased excretion in the urine in amounts three to five times those of normal mice. Extraneural ectopic hormone production was found only in the pancreas. Despite chronic hypersecretion of AVP, 24-hour urine volume and osmolality did not show evidence of increased antidiuretic hormone action on the kidney, so that, under basal conditions, the water balance in the animals is unaffected.

Inhibitory effect of oolong tea polyphenols on glycosyltransferases of mutans Streptococci.

Oolong tea extract (OTE) was found to inhibit the water-insoluble glucan-synthesizing enzyme, glucosyltransferase I (GTase-I), of Streptococcus sobrinus 6715. The GTase-inhibitory substance in the OTE was purified successive adsorption chromatography on Diaion HP-21 and HP-20 columns; this was followed by further purification by Sephadex LH-20 column chromatography. A major fraction that inhibited GTase activity (fraction OTF10) was obtained, and the chemical analysis of OTF10 indicated that it was a novel polymeric polyphenol compound that had a molecular weight of approximately 2,000 and differed from other tea polyphenols. Catechins and all other low-molecular-weight polyphenols except theaflavin derived from balck tea did not show significant GTase-inhibitory activities. It was found that OTE amd PTF10 markedly inhibit GTase-I and yeast alpha-glucosidase, but not salivary alpha-amylase. Various GTases purified from S. sobrinus and Streptococcus mutans were examined for inhibition by OTE and OTF10. It was determined that S. sobrinus GTase-I and S. mutans cell-free GTase synthesizing water-soluble glucan were most susceptible to the inhibitory action of OTF10, while S. sobrinus GTase-Sa and S. mutans cell-associated GTase were moderately inhibited; no inhibition of S. sobrinus GTase-Sb was observed. Inhibition of a specific GTase or specific GTases of mutants streptococci resulted in decreased adherence of the growing cells of these organisms. The inhibitory effect of OTF10 on cellular adherence was significantly stronger than that of OTE.

Oolong tea polyphenols inhibit experimental dental caries in SPF rats infected with mutans streptococci.

An extract of oolong tea (semifermented tea leaves of Camellia sinensis) and its chromatographically isolated polyphenolic compound was examined for in vitro inhibitory effects on glucosyltransferases (GTases) of mutans streptococci and on caries development in Sprague-Dawley rats infected with mutans streptococci. The samples showed no detectable effect on the growth of mutans streptococci. However, insoluble glucan synthesis from sucrose by the GTases of Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 was markedly inhibited, as was sucrose-dependent cell adherence of these mutans streptococci. The administration of the oolong tea extract and the isolated polyphenol compound into diet 2000 and drinking water resulted in significant reductions in caries development and plaque accumulation in the rats infected with mutans streptococci. The active components in the oolong tea extract were presumptively identified as polymeric polyphenols which were specific for oolong tea leaves. These results indicate that the oolong tea polyphenolic compounds could be useful for controlling dental caries.

[Combined action of cephamycin and aminoglycoside antibiotics].

The combined actions of cefoxitin (CFX) with amikacin (AMK), gentamicin (GM) and dibekacin (DKB) were studied against Gram-positive and Gram-negative bacteria. The following results were obtained. The synergistic actions of CFX with AMK, GM and DKB were observed on S. aureus, S. epidermidis, E. coli, S. marcescens, K. pneumoniae, Proteus spp. and Acinetobacter by checker board titration method. The combination of CFX with AMK was most effective. In case of the combination of CFX with AMK, the simultaneous administration showed the highest bactericidal effect, followed by the case of addition of AMK after adding CFX. The phase-contrast microscopic observation on S. marcescens revealed that the bacterial cell prolonged with CFX showed a filament-like form and with AMK almost a normal form. In the combination, lysed cells were observed. The therapeutic experiment of S. marcescens infection in mice demonstrated that the combination of CFX with AMK showed superior effect than that of each drug alone.