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R Beaudet

Publications and source records attributed to R Beaudet.

At least 73 records · Page 4Linked to original sources
PubMed1982

Bactericidal and bacteriostatic antigonococcal activities produced by urogenital staphylococci.

We have overcome some of the difficulties in obtaining soluble antigonococcal activity produced by staphylococci by using a very sensitive detection method. This method is based on the light absorbance determinations of liquid cultures of the gonococcus incubated for 6 h in the presence of serial dilutions of the inhibitor as compared to the absorbance of uninhibited control cultures. Antigonococcal activity was detected in the liquid phase prepared from semisolid agar cultures of all twenty two staphylococcal isolates tested. Sixteen supernatants from liquid cultures were also found to be active. The antigonococcal activity detected was differentiated by colony forming units counts into two types, bacteriostatic and bactericidal. After 6 h of incubation of the gonococcus in the presence of five arbitrary units (AU)/ml of the bactericidal activity produced by one of the strains of staphylococci, isolate 37, the loss of viability was over 99.9%, while 10 AU/ml of the bacteriostatic activity produced by isolate 66 did not cause any loss of viability of the gonococcus.

Bacteriocins↗
PubMed1982

Inhibitors of Neisseria gonorrhoeae produced in liquid medium by Bacteroides fragilis and Eubacterium limosum.

Indigenous micro-organisms of the urogenital flora including anaerobes can inhibit the in vitro growth of Neisseria gonorrhoeae. Bacteroides fragilis and Eubacterium limosum strains known to inhibit the gonococcal growth on solid medium have been shown to produce their antigonococcal activities in liquid medium. Concentrations of individual short-chain fatty acids produced by E. limosum strains were lower than the inhibitory concentrations reported for N. gonorrhoeae. B. fragilis strains produced propionic acids in amounts known to be inhibitory to the gonococcus. Furthermore, studies with E. limosum (Ps11A) cultures incubated at 29 degrees C (200 ml, 50 l) and at 37 degrees C (200 ml) have shown that short-chain fatty acids were not the inhibitors since no correlation between the short-chain fatty acids and the antigonococcal activity was found throughout the growth of the cultures. Moreover, the observed inhibitory activity of E. limosum was not due to pH change or to nutrient depletion of the medium. These observations coupled with the specificity of the antigonoccal activity produced by E. limosum suggest that it is different from previously reported gonococcal inhibitors of bacterial origin.

Anti-Bacterial Agents↗
PubMed1981

In vitro antigonococcal activity of urogenital coagulase-negative staphylococci.

Twenty-four urogenital isolates of coagulase-negative staphylococci were selected because of their demonstrated ability to inhibit Neisseria gonorrhoeae growth in vitro. These organisms showed quantitative differences in their growth-interfering capability as revealed by a flip-flop agar overlay method. The composition of the culture medium affected the production of antigonococcal activity. Antigonococcal activity was shown with the following media: GC agar base with Lankford defined supplement, brain heart infusion agar, trypticase soy agar, and dextrose starch agar, but not with the GC agar base with CVA enrichment. An antigonococcal activity was obtained in the liquid phase prepared from semisolid agar cultures for 10 of the 24 staphylococcal isolates, whereas no activity was found in the supernatant from liquid cultures. The production of antigonococcal activity by staphylococci in vitro is influenced by growth conditions.

Antibiosis↗
PubMed1981

Antigonococcal and antibacterial spectra of some bacterial isolates of the urogenital flora.

The antigonococcal and antibacterial spectra of bacterial isolates of the urogenital flora selected for their in vitro interference of Neisseria gonorrhoeae growth were determined on solid medium. A broad antigonococcal spectrum was found for all the selected isolates when they were tested against gonococcal virulent (T1) strains, penicillinase producing strains and strains belonging to the auxotypes NR, Thi-, Pro- Hyx-, Pro- Meth- Thp-, Arg- Meth- and Arg- Hyx- Ura-. Except for the group D streptococci, all the selected isolates particularly the coagulase negative staphylococci showed a narrow interference spectrum towards aerobic and anaerobic bacterial representatives of the normal urogenital flora. The selected isolates inhibited also the growth of N. meningitidis and N. catarrhalis meaning that they produce antineisserial rather than antigonococcal activities. The crude preparations isolated from cultures of Micrococcus sp. No. 2 and 42, and Acinetobacter sp. No. 13 on solid medium showed similar antigonococcal and antibacterial spectra as those observed with the basal spot/lawn method. These inhibitory activities were characterized for stability to extreme of temperature and pH values, and for susceptibility to different enzyme treatments. Based on ultrafiltration, differences in molecular size were observed between the inhibitors. These substances appear different from the previously reported gonococcal inhibitors of bacterial origin.

Aerobiosis↗
PubMed1980

Defense preference and stutterers' speech disfluencies: implications for the nature of the disorder.

Psychological defense mechanism preference was assessed in 16 adult stutterers. From this group, two subgroups of six subjects each were identified by their opposite extremes in defensive style: (1) expressive defenders; (2) avoidance defenders. Subsequently, these subgroups were found to be significantly different in measures of stuttering frequency and disfluency type. The expressive defenders showed higher frequency stuttering than the avoidance defenders (21.5% vs. 4.66%) while the avoidance subgroup showed preference for the use of accessory-type disfluencies; that is, interjections, phrase repetitions, and whole word repetitions. The possibility that the speech disfluencies of stutterers may vary as a function of defense preference is discussed in relation to: (1) definitions of stuttering phenomena and the disorder; (2) the developmental nature of stuttering as a problem and the role of learning; (3) different syndromes of stuttering; and (4) the contributions of etiologic versus pathogenic factors to the origins of the disorder.

Adult↗
PubMed1980

In vitro inhibition of Neisseria gonorrhoeae growth by strict anaerobes.

Thirty two anaerobic bacterial strains were screened for their in vitro inhibitory activity toward 21 Neisseria gonorrhoeae strains, including two penicillin-resistant strains. From this screening, six anaerobic bacteria belonging to the genera Bacteroides, Peptostreptococcus, and Eubacterium were selected for their large antigonococcal spectrum of activity. The inhibitory activity of these six strains appears to be specific to the gonococcus as a variety of anaerobes and aerobes were not generally inhibited by these strains. The antigonococcal effect was not due to pH change or nutrient depletion of the media.

Bacteroides↗
PubMed1980

Interference of Neisseria gonorrhoeae growth by aerobic bacterial representatives of the urogenital flora.

Aerobic bacterial isolates obtained from endocervical, vaginal and urethral swabbings were tested for interference of neisseria gonorrhoeae growth on solid medium. Simultaneous antagonism was studied using the lawn spotting method, and delayed antagonism by the basal spot/lawn method. From 58 swabbings we recuperated a total of 181 isolates, 71 of those were found interfering with at least one out of four gonococcal strains (G-1, G-2, G-3 and G-4). Similar percentages of interfering isolates were obtained from each of the isolation sites. The identification of the interfering isolates has revealed that similar numbers of coagulase negative staphylococci and identical numbers of group D streptococci were found for each of those sites. The majority of the interfering isolates and also of the inhibitory coagulase negative staphylococci showed only simultaneous antagonism. To complete the interference spectrum, we have tested all the active urogenital isolates against four other gonococcal strains (G-7, G-9, G-10 and G-11). This spectrum showed clearly that interference is not an all or none phenomenon. While the gonococcal interference spectrum of most of the Gram positive cocci and the Acinetobacter sp. strains is broad, that of all the other isolates is relatively narrow. Gonococcal strains G-7 and G-9 were the most susceptible to inhibition by the interfering urogenital isolates while strain G-3 was the most resistant one.

Acinetobacter↗
PubMed1977

[Effect of open heart surgery on the defense mechanisms against bacterial infections].

Extracorporeal circulation during open-heart surgery may damage cellular and humoral factors in the blood. Phagocytic functions of circulating polymorphonuclear leukocytes were investigated in 10 patients 1 day before, then 1 hour, 2, 4 and 10 days after open-heart surgery. Transient diminutions in the phagocytic capacity of polymorphs was found for Staphylococcus aureus and Escherichia coli in one patient, and E. coli only in two patients up to the 4th postsurgical day. A positive correlation was found between the duration of extracorporeal circulation and the transient diminutions in phagocytic capacity for these three patients. However, the bactericidal capacity of polymorphs and their capacity to reduce nitroblue tetrazolium were normal in all patients. The serum concentrations of total hemolytic complement, C3, IgG and IgM were generally diminished up to the 4th day after surgery, but the opsonic power of the serum was almost normal in all the patients.

Adult↗
PubMed1976

Formiminotransferase cyclodeaminase from porcine liver. An octomeric enzyme containing bifunctional polypeptides.

The forminiminotransferase-cyclodeaminase complex contains 2.8% carbohydrate and is composed of identical subunits based on molecular weight, isoelectric focusing and the number of CNBr-generated peptides. Electron microscopy demonstrated that the complex is a ring-shaped molecule when negatively stained both in solution and in crystalline structures. Rotational reinforcement of electron micrographs reveals that the molecule is composed of eight subunits arranged in a planar ring. These results indicate that each polypeptide of the complex must contain both enzymic activities.

Amino Acids↗
PubMed1975

Kinetic mechanism of formininotransferase from porcine liver.

Formiminotransferase (EC 2.1.2.5) and cyclodeaminase (EC 4.3.1.4) constitute an enzyme complex that catalyses two sequential metabolic reactions. The activity of native formiminotransferase can be measured without interference from cyclodeaminase, and its kinetic mechanism has been investigated. Although initial velocity plots yield families of parallel lines suggesting that the transferase utilizes a ping-pong mechanism, product inhibition and alternate substrate studies with tetrahydropteroic acid clearly show the mechanism to be sequential. Of the possible mechanisms compatible with these observations, several could be ruled out through the effects of various dead-end inhibitors. The data indicate that the transferase mechanism is rapid equilibrium random with formation of a dead-end complex enzyme-tetrahydrofolate-glutamate.

Ammonia-Lyases↗
PubMedDate not supplied

Stimulation of non-specific anti-tumour resistance in the mouse using cell wall preparations from four BCG substrains.

The comparative anti-tumour activity of cell walls, deproteinized cell walls and cell wall skeleton (CWS) isolated from four BCG substrains (Canadian, Russian, Glaxo and Swedish) was determined against Ehrlich ascitic carcinoma in CF-1 mice and against L1210 lymphoid leukaemia in B6D2F1/J mice. In Ehrlich carcinoma, the protocol of injection was shown to be of critical importance, since high and low levels of protection and even facilitation of tumour growth were observed according to the protocol used. The oil emulsion used as the vehicle for injection of the fractions (control groups) induced facilitation of tumour growth with some protocols. The highest levels of protection were observed when treatment was performed on day -6 for a single i. p. injection or on days -14 and 0 for two injections. Using the former protocol of immunization, the highest level of protection was detected with cell walls and deproteinized cell walls. CWS isolated from the Canadian and Glaxo substrains were found to be inactive, whereas those isolated from the Swedish and Russian substrains induced significant levels of protection. In L1210 leukaemia, very few preparations induced significant protection. CWS preparations did not induce protection. Canadian and Russian deproteinized cell walls and Canadian cell walls (100 and 250 micrograms, respectively) induced some protection. The use of different protocols of injection did not increase the anti-tumour activity of the Canadian cell walls. The most active preparation in both tumour systems was that of Canadian deproteinized cell walls.

Animals↗
PubMedDate not supplied

Two-liquid-phase slurry bioreactors to enhance the degradation of high-molecular-weight polycyclic aromatic hydrocarbons in soil.

High-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs) are pollutants that persist in the environment due to their low solubility in water and their sequestration by soil and sediments. The addition of a water-immiscible, nonbiodegradable, and biocompatible liquid, silicone oil, to a soil slurry was studied to promote the desorption of PAHs from soil and to increase their bioavailability. First, the transfer into silicone oil of phenanthrene, pyrene, chrysene, and benzo[a]pyrene added to a sterilized soil (sandy soil with 0.65% total volatile solids) was measured for 4 days in three two-liquid-phase (TLP) slurry systems each containing 30% (w/v) soil but different volumes of silicone oil (2.5%, 7.5%, and 15% [v/v]). Except for chrysene, a high percentage of these PAHs was transferred from soil to silicone oil in the TLP slurry system containing 15% silicone oil. Rapid PAH transfer occurred during the first 8 h, probably resulting from the extraction of nonsolubilized and of poorly sorbed PAHs. This was followed by a period in which a slower but constant transfer occurred, suggesting extraction of more tightly bound PAHs. Second, a HMW PAH-degrading consortium was enriched in a TLP slurry system with a microbial population isolated from a creosote-contaminated soil. This consortium was then added to three other TLP slurry systems each containing 30% (w/v) sterilized soil that had been artificially contaminated with pyrene, chrysene, and benzo[a]pyrene, but different volumes of silicone oil (10%, 20%, and 30% [v/v]). The resulting TLP slurry bioreactors were much more efficient than the control slurry bioreactor containing the same contaminated soil but no oil phase. In the TLP slurry bioreactor containing 30% silicone oil, the rate of pyrene degradation was 19 mg L(-)(1) day(-)(1) and no pyrene was detected after 4 days. The degradation rates of chrysene and benzo[a]pyrene in the 30% TLP slurry bioreactor were, respectively, 3.5 and 0.94 mg L(-)(1) day(-)(1). Low degradation of pyrene and no significant degradation of chrysene and benzo[a]pyrene occurred in the slurry bioreactor. This is the first report in which a TLP system was combined with a slurry system to improve the biodegradation of PAHs in soil.

Biodegradation, Environmental↗
PubMedDate not supplied

In vitro inhibition of growth of Neisseria gonorrhoeae by Neisseria meningitidis isolated from the pharynx of homosexual men.

Despite the high prevalence of pharyngeal gonorrhea and of meningococcal carriage among homosexual men, Neisseria gonorrhoeae and Neisseria meningitidis are rarely co-isolated from the throat. Forty-seven meningococcal isolates from the pharynx of homosexual men were examined, by a lawn-spotting method, for their ability to inhibit N. gonorrhoeae in vitro. Eight (17%) of the meningococcal isolates were inhibitory when tested against gonococci from the same patient, while 31 (66%) were inhibitory when tested against N. gonorrhoeae strain 650 (T1). The colonial type T1 of a given strain was, in all cases tested, more sensitive to the inhibitory activities than the corresponding T4 type. Since the meningococci co-isolated from the throat with gonococci were at least as inhibitory in vitro as those isolated without gonococci, the natural resistance to gonococcal pharyngitis cannot be explained on the basis of the inhibitory activities produced by the meningococci in vitro. The inhibitory strains of N. meningitidis were identified in decreasing importance as: nonserogroupable, W135, C, B, 29E, and X. The addition of trypsin to the solid medium removed the inhibition produced by the meningococci, an observation suggesting the involvement of protein inhibitors.

Animals↗