in vitro is established that bacteria of Pseudomonas aeruginosa and the Candida guillermondii yeast capable to cause in people and animals of a disease of a pseudo-monose and candidiases are respectively sensitive to antimicrobic effect of solutions of a secret of salivary cages of a medical bloodsucker of Hirudo medicinalis, and also water extract from the preparation Piyavit allowed for clinical use. The main stages of a lizis of microbic cages under the influence of the studied solutions are defined by electronic microscopy. Симбионт medical bloodsuckers Aeromonas hydrophila bacterium, is almost tolerant to influence of solutions as secret of salivary cells of the owner, and preparation Piyavit. The conclusion is drawn on prospects of use of the studied natural antimicrobic complexes which aren´t causing resistance in microorganisms for treatment of diseases instead of traditionally used antibiotics.
The aim of this study was to investigate the salivary immunoglobulin A concentration in rapid and slow plaque formers. After 3 days of oral hygiene abstinence, 49 healthy volunteers were screened using the plaque index (PI) to assess their plaque formation rates. Five subjects with the highest, and five with the lowest mean PI were selected as rapid and slow plaque formers, respectively. Unstimulated whole saliva was collected from each of these ten subjects and the levels of salivary IgA assessed using a conventional ELISA technique. Reference curves for salivary IgA were established by testing serial dilutions of human IgA with known concentrations. When the differences between the two groups were compared, almost a twofold increase in the mean salivary IgA concentration in the slow (16 microg/ml +/- 4) compared with the rapid (9 microg/ml +/- 3) plaque formers was recorded (p < 0.05). These findings, reported for the first time, imply that salivary IgA may play a crucial role in regulating the pioneer plaque development on enamel surfaces.
The quantitative analysis of laboratory grown organisms (Plectonema boryanum and Staphylococcus aureus) revealed that a typical in vivo polyphosphate body (PPB) contains O (4.3 x 10(-8) microg), C (1.2 x 10(-8) microg), P (6.7 x 10(-9) microg), Mg (1.3 x 10(-9) microg), Ca (6.7 x 10(-10) microg), K (6.7 x 10(-10) microg), Fe (6.0 x 10(-10) microg), S (5.4 x 10(-10) microg) and Al (5.9 x 10(-10) microg). Quantitative X-ray analysis of samples from nature showed PPB contain O (1.63 x 10(-8) microg), C (4.75 x 10(-9) microg), P (2.50 x 10(-9) microg), Mg (5.0 x 10(-10) microg), Ca (2.50 x 10(-10) microg), K (2.50 x 10(-10) microg), Fe (2.25 x 10(-10) microg) and S (2.0 x 10(-10) microg). The mass of an average polyphosphate body was 6.7 x 10(-8) microg for P. boryanum, 2.5 x 10(-8) microg for S. aureus and for microbes from the natural environment 6.3 x 10(-8) microg. The results indicate that the PPB may have other unknown functions in addition to essential element storage, acting as a detoxification method by sequestering heavy metals and providing a homeostasis system in the cell.
Cellular polyamines of four new thermophiles located in three early branched eubacterial clades, were investigated for the chemotaxonomic significance of polyamine distribution profiles. The thermophilic anaerobic Thermosipho japonicus, belonging to the order Thermotogales, contained norspermidine, norspermine and thermospermine in addition to spermidine and spermine. The polyamine profile was identical to the polyamine composition of Thermotoga, Fervidobacterium and Petrotoga species of the order. Spermidine, norspermidine, spermine, N4-bis(aminopropyl)spermidine and agmatine were found in thermophilic aerobic Thermaerobacter marianensis. Some differences were observed in the polyamine compositions of the phylogenetically related thermophilic anaerobes, Moorella, Dictyoglomus, Thermoanaerobacterium and Thermoanaerobacter species. Thermophilic anaerobic Caldicellulosiruptor kristianssonii and Caldicellulosiruptor owensensis contained a linear penta-amine, thermopentamine, and two quaternary branched penta-amines, N4-bis(aminopropyl)spermidine and N4-bis(aminopropyl)norspermidine, as the major polyamines. A novel tertiary branched penta-amine, N4-aminopropylspermine, was found in the two Caldicellulosiruptor species.
Growth inhibition and arylamine N-acetyltransferase (NAT) activity in Neisseria gonorrhoeae were inhibited by luteolin, a drug which originated from herbs. The growth inhibition was based on changes in optical density (OD) using a spectrophotometer, and arylamine NAT activity with 2-aminofluorene (2-AF) was determined using high pressure liquid chromatography. The inhibition of growth in N. gonorrhoeae demonstrated that luteolin elicited a dose-dependent growth inhibition in the N. gonorrhoeae cultures. Suspensions of N. gonorrhoeae with or without specific concentrations of luteolin cotreatment showed different percentages of 2-AF acetylation. The data indicated that there was reduced NAT activity associated with increased levels of luteolin in N. gonorrhoeae suspensions. Time-course experiments showed that NAT activity measured from intact N. gonorrhoeae cells was inhibited by luteolin for at least 4 h. Using standard steady-state kinetic analysis, it was demonstrated that luteolin was a possible uncompetitive inhibitor to NAT activity in N. gonorrhoeae. This report is the first to show that luteolin can inhibit N. gonorrhoeae NAT activity.
Outbreaks of mass mortality among cultured small abalone Haliotis diversicolor supertexta with abscess/ulcers in the mantle occurred in 1998 at Kao-Hsiung, Taiwan. A swarming bacterium, strain H-11 was isolated from the haemolymph of the moribund small abalone using tryptic soy agar supplemented with 3% NaCl and/or thiosulphate citrate bile salt sucrose agar. This strain was characterized and identified as Vibrio alginolyticus on the basis of various biochemical tests. The H-11 strain and its extracellular products were virulent to small abalones with LD50 values of 3.6 x 10(5) colony forming units and 2.96 microg protein/g body weight, respectively.
Cassava flour was evaluated as a partial substitute for wheat flour in gluten-free muffins. Four replicate test bakes were carried out to evaluate the microbial ecology of two muffin mixes, made with different combinations of cassava, soya, sorghum, sago, and potato flour. The muffins were baked at 180 degrees C for 25 min, stored at 30 degrees C and analysed microbiologically for up to 10 days post-baking. Raw materials were similarly analysed microbiologically on the day of baking. Characterization of predominant bacterial and mould isolates from the raw materials and the muffins was carried out. The rope-free and minimum mould-free shelf life of both muffin types were approximately 1 day and approximately 3 days, respectively. The predominant bacterial isolates from the raw materials and muffins were Bacillus species (83 and 99%, respectively). The moulds predominating in the raw materials were Gloeosporium (42%), Penicillium (13%) and Mucorales (13%), and from muffins Penicillium (37%) and Aspergillus (37%).
The diagnostic reliability of the Enzygnost EBV test (DadeBehring, Germany) for the detection of IgG and IgA antibodies in the diagnosis of Epstein-Barr virus (EBV) recurrent disease was investigated. Of 81 serum samples examined there were fourteen asymptomatic patients without EBV infection, 46 with past EBV infection, and 21 patients with EBV reactivation. The Enzygnost EBV test was based on an enzyme-linked immunosorbent assay with a pool of viral antigens. The reliability of IgG at >650 IU/ml, and IgA for the diagnosis of reactivation or chronic persistent EBV infection gave 100% sensitivity, 83.3% and 98.3% specificity, respectively. The data indicated that the appearance of EBV IgA was associated with EBV reactivation together with clinical manifestations.
The effects of subminimal inhibitory concentrations (sub-MIC) of four beta-lactam antibiotics [penicillin-G (PCG), ampicillin (AMP), cephaloridine (CER), cephalothin (CET)] were tested against Clostridium perfringens type A PB6K, after determining the minimum inhibitory concentrations (MIC) of 29 different Clostridium strains. The majority of the strains were sensitive to all beta-lactam antibiotics. Morphological changes, such as filamentous development and lysis, occurred at concentrations considerably lower than the MIC of CER and CET in C. perfringens. Clear cooperation of AMP and CER with rabbit polymorphonuclear leucocytes (PMNL) against C. perfringens was observed. The filamentous bacteria produced as a result of exposure to sub-MIC of each antibiotic, were phagocytosed easily. The ratios between the drug concentrations (microg/ml) at which the morphological changes began to occur, the minimum antibiotic concentrations (MAC), and the MIC values (microg/ml), were calculated. A large ratio indicated a wide range of effective concentrations below the MIC value for the antibiotics.
Many clinical symptoms of malaria are associated with alterations in certain haematological parameters during acute and subclinical infections. Total leucocyte and erythrocyte counts, haemoglobin concentration, haematocrit and other minor indices, were investigated in five cohort groups of individuals resident in a malaria hyperendemic area of western Kenya. The groups included age- and sex-matched adults with acute Plasmodium falciparum malaria, aparasitaemic adults, children with acute malaria, aparasitaemic children and asymptomatic-parasitaemic school children. The study aimed at defining what constitutes immunity to malaria which may be important in the critical evaluation of malaria vaccine antigens. Anaemia was more severe in adults and children with acute malaria than in their age- and sex-matched aparasitaemic and asymptomatic-aparasitaemic school children. Lymphocyte counts were significantly higher in asymptomatic-aparasitaemic school children than in aparasitaemic adults, suggesting a possible functional role for lymphocytes in the anti-disease immunity in the former group.
Hepatitis C virus serotypes and the duration of infection HCV positive subjects from a restricted geographical area in Italy, were evaluated. HCV serotypes were determined by Murex serotyping assay. Serotypes were detected in 592 (88.0%) of 669 samples. Type 1 proved to be the most frequent (48.9%), followed by types 2 (29%), 3(4.5%) and 4 (2.1%). The transmission of HCV 3 and 4 were observed only in the past 20 years whilst those of other types were recorded during 40 or more years. The results support the view that the prevalence of different HCV types of infection in one restricted geographical area may be associated with the source and duration of infection.
Outbreaks of diarrhoea and haemolytic uraemic syndrome have been associated with the consumption of apple cider and apple juice. The organism implicated in these outbreaks has been Escherichia coli O157:H7, indicating the resistance of the serotype to acidic pH. On comparing the growth of this serotype with a control strain of E. coli, it was found that strain O157:H7 grew well in trypticase soy broth at pH levels ranging from 2.0 to 9.0, while control strains failed to grow at pH levels below 4.0 and above 9.0. The growth of both strains were inhibited by adding 0.05% of either benzoic acid or sorbic acid. Similarly, O157:H7 grew well in both natural (unpasteurized) as well as in pasteurized apple juice and the growth was inhibited by adding 0.1% of either benzoic acid or sorbic acid. Control strains of E. coli failed to grow in either types of apple juice. The possible sources of contamination of natural apple juice with O157:H7 serotype are discussed.
The in vitro antibacterial activity of the glass-ionomer restorative cements Ketac-Cem, Ketac-Bond, Ketac-Silver and Vitrebond was studied in conjunction with 32 strains of five bacteria involved in the development of caries: Streptococcus spp., Lactobacillus spp., Actinomyces spp., Porphyromonas spp. and Clostridium spp. The agar plate diffusion method was used for the cultures, which included a chlorhexidine positive control. All the glass-ionomer cements tested inhibited bacterial growth, but with considerable differences in the scope of their action. Of the four cements, Vitrebond, a resin-modified glass-ionomer cement, was determined to be the most effective bacterial inhibitor.
In a previous in vitro investigation from the same laboratory a therapeutic level of hydrocortisone enhanced the itraconazole susceptibility of a single strain of Aspergillus fumigatus. In the present work, the influence of therapeutic levels of hydrocortisone (1 microM), prednisolone (0.125 microM 0.25 microM and 0.5 microM) and dexamethasone (0.25 microM and 0.5 microM) on the itraconazole susceptibility of four A. fumigatus strains, was determined. A. fumigatus conidia were germinated either in the absence or in the presence of a glucocorticoid. The germinated conidia were then spread onto plates and grown either in the presence or in the absence of a glucocorticoid, together with increasing concentrations of itraconazole. The mean colony forming units (CFU) were measured. Two factor analyses of variance showed that hydrocortisone significantly (p <0.001) potentiated the action of itraconazole. The cytotoxic effect of prednisolone on the fungal strains added significantly to the effect of itraconazole (p <0.001). Dexamethasone was also cytotoxic to the fungus but, when used in conjunction with itraconazole, it effectively increased (p <0.01) the number of CFU. This study showed a direct effect of glucocorticoids, currently in use for patient therapy, on in vitro A. fumigatus susceptibility to itraconazole.
Using three different plasmid DNA codings for kanamycin (KM), chloramphenicol (CP), and ampicillin- (AMP) and tetracycline- (TC) resistance, four different competent Escherichia coli strains were transformed by the calcium chloride method to produce KM-, CP- and AMP- and TC-resistant strains. Evaluation of minimum inhibitory concentrations (MIC) of 22 antibiotics, showed KM-resistant E. coli to be cross resistant only to fradiomycin (FRM); CP-resistant E. coli, especially HB101 and JM109 strains, exhibited cross-resistance only to thiamphenicol (TP). On the other hand, AMP- and TC-resistant E. coli showed cross resistance to several penicillins, tetracyclines and erythromycin. E. coli ATCC-27166, the strain most sensitive to all drugs in this experiment, was employed for disc diffusion experiments and from the pattern of appearance of the inhibition zone, eight major antibiotics were divided into three groups depending on their activity against containing each of the three plasmids. Only gentamicin (GM) activity was not affected by any of the drug resistant strains. Assay techniques utilizing three resistant strains may be the technique for screening foods for antibiotic residues in the future.
2,4-Dichlorophenoxyacetate (2,4-D)/alpha-ketoglutarate (alpha-KG) dioxygenase has been purified to apparent homogeneity from Burkholderia cepacia strain 2a, which utilizes 2,4-D as sole carbon source. The enzyme required ferrous ions, and was a homodimer composed of subunits having an Mr of approximately 32,000. The reaction catalysed consumed one mol each of 2,4-D, alpha-KG and dioxygen, with the production of one mol each of succinate, 2,4-dichlorophenol and glyoxylate. Maximum activity was exhibited at pH 7.8 and 25 degrees C, and reactivity was enhanced by the presence of ascorbate and cysteine. Mn2+, Zn2+, Cu2+, Fe3+ and Co2+ were inhibitory, and chemical modification of the dioxygenase revealed that thiol groups were essential for activity. The enzyme was active towards other substituted phenoxyacetates, but reacted most rapidly with 2,4-D. The apparent Michaelis constants for 2,4-D and alpha-KG were 109 and 8.9 microM, respectively. The properties of this enzyme are compared with those of the 2,4-D/alpha-KG dioxygenase from Ralstonia eutropha JMP134, which exhibits a differing N-terminal amino-acid sequence, and a different temperature 'optimum', pH optimum, substrate specificity and sensitivity to thiol-binding reagents.
The antibacterial activity of sixteen Chilean red wines (Cabernet Sauvignon, Cabernet Merlot, Cabernet Organic and Pinot Noir), and the active extracts of two randomly selected wines were assayed for their antibacterial activity on six strains of Helicobacter pylori isolated from gastric biopsies. The active fraction of the wines was obtained by dichloromethane extraction, and the antibacterial activity of the wines and extracts was evaluated by an agar diffusion method. All the red wines studied showed some antibacterial activity on the six strains of H. pylori, although the strains were heterogeneous in their susceptibility to each particular wine. The active fraction of the two wines selected also showed good activity against the strains tested. The main active compound was identified as resveratrol. The results presented indicate that Chilean red wines have antibacterial activity against H. pylori, which depends mainly on the presence of resveratrol.
The effect of the initial pH of the culture medium used in the production of the exopolysaccharide gellan by the bacterium Pseudomonas species ATCC 31461, when glucose or corn syrup served as the carbon source, was investigated. With glucose as the carbon source, exopolysaccharide formation was highest after 72 h of growth when the initial pH of the culture medium was 6.8 to 7.4. Polysaccharide production by the bacterial cells grown on corn syrup for 72 h was maximal when the initial pH of the medium was 7.0 or 7.2. Cell weights of the strain after 72 h tended to be higher for the glucose-grown cells than for the corn syrup-grown cells.
The production of enzymes by micro-organisms which are found on vegetal substrates is important due to their ability to decompose cellulose, lignin and other components, which guarantee the integrity of the vegetal cell. The objective of this study was to determine the enzymatic activity of filamentous fungi, yeasts and bacteria, isolated from natural cork stoppers for bottles of still and sparkling wines. Suspensions of fungal conidia, yeasts and bacterial cells of micro-organisms were established in concentrations of 10(6) CFU/ml. The enzymatic activity of these micro-organisms was evaluated by means of the API ZYM system, with which it was possible to determine and semi-quantify nineteen enzymatic activities simultaneously. The enzymes produced by all of the species were esterase (C1), esterase lipase and naphthol-AS-BI-phosphohydrolase. The micro-organisms with the greatest enzymatic activity were Monilia sitophila, Alternaria alternata, Aspergillus niger and Aeromonas sp.
