Transformation of Phenol into Phenylalanine by a Methanogenic Consortium

The conversion by a methanogenic consortium of phenol into phenylalanine, with benzoic and phenylpropionic acid as intermediates, was investigated. When (sup14)C-labelled phenol was fed to the consortium, the radioactivity was mostly transferred into methane and CO(inf2), but 4% of the radioactivity was found in the water fraction after extraction of the culture medium with an organic solvent. Utilization of labelled compounds and analysis by gas chromatography coupled with mass spectrometry revealed that a fraction of the benzoic acid produced was transformed into 3-phenylpropionic acid. When fully (sup13)C-labelled acetic acid was fed to the consortium, the labels were incorporated at the 1 and 2 positions of 3-phenylpropionic acid. When deuterium-labelled 3-phenylpropionic acid was fed to the consortium, part of the phenylalanine of the biomass was labelled. These metabolic transformations are reversible, since deuterium-labelled phenylalanine generated labelled 3-phenylpropionic acid. Cinnamic acid was also transformed into 3-phenylpropionic acid.     

Do consensus conferences influence their participants?

OBJECTIVE: To determine whether participation in a consensus conference on the assessment of dementia would influence conference participants with respect to their recommendations to primary care physicians for the assessment of dementia. DESIGN: Questionnaire before and after the conference. SETTING: Canadian Consensus Conference on the Assessment of Dementia, held in Montreal, Oct. 5 and 6, 1989. PARTICIPANTS: All 38 experts representing relevant health disciplines who participated in the consensus conference; 36 completed both questionnaires. OUTCOME MEASURES: Participants'' opinion before and after the conference as to how frequently each of 28 manoeuvres (12 blood tests, 4 neurologic imaging procedures, 4 types of consultation and 8 "other" tests) should be ordered by primary care physicians as part of an assessment of a patient with dementia suspected in clinical grounds. RESULTS: For 18 (64%) of the 28 manoeuvres (10 of the 12 blood tests, 3 of the 4 neurologic imaging procedures and 5 of the 8 "other" tests), there was a shift in opinion after the conference toward recommending that primary care physicians order them less often; for 10 of these 18 (5 blood tests and 5 "other" tests) the shift was statistically significant. For the remaining 10 manoeuvres (36%) the shift in opinion was toward a recommendation that primary care physicians order them more often; the shift was not statistically significant for any of these 10 manoeuvres. CONCLUSION: Expert members of a consensus conference are influenced by the process of having participated in such a conference and are capable and willing to chance their initial recommendations when confronted with relevant data.     

In-vivo labeling of (3H)D-aspartate uptake sites in monkey retina

Summary Following prolonged topical application of (³H)D-aspartate in vivo, selective labeling of three distinct cell classes was observed in light-microscopic radioautographs from squirrel monkey retina. Müller (glial) cell bodies and their processes were intensely and consistently labeled in all preparations. Moderately labeled perikarya were occasionally detected in the area of bipolar cells, within the inner nuclear layer. These were particularly numerous in sections from the central retina where an intense diffuse labeling of the inner plexiform layer was also prominent. Finally, moderate to dense accumulations of label were observed over the cell bodies, internal segments and fiber processes of cone photoreceptors. These results strongly suggest that cones, as well as a sub-population of bipolar cells, use glutamate and/or aspartate as neurotransmitter(s) in monkey retina.     

Linkage of DNA markers to cystic fibrosis in 26 families.

Two DNA markers, the met oncogene and the anonymous probe, pJ3.11, previously reported to be tightly linked to cystic fibrosis (CF), were used for linkage analysis in 26 families with two or more individuals affected with CF. A new high frequency polymorphism was identified using BanI and the pmetD probe. The results of linkage analysis were as follows: between met and CF, lod score of 18.2 at theta of .009; between pJ3.11 and CF, lod score of 12.1 at theta of 0; and between met and pJ3.11, lod score of 16.7 at theta of 0. These data indicate that most or all of CF is due to an abnormality at a single locus and that the DNA markers are useful for prenatal diagnosis and heterozygote detection within affected families.     

Effect of culture medium composition on inhibition of growth ofNeisseria gonorrhoeae by lactobacilli

The role of genital microorganisms in resistance to gonococcal infection is usually based on their in vitro inhibition of gonococcal growth. Three different culture media (GC, DSA, and MRS) were evaluated for their ability to support the growth of 23 lactobacilli strains and the detection of the antigonococcal activity of these bacteria. The MRS medium was the most suitable medium for the growth of lactobacilli since it favored a good growth of all the lactobacilli strains tested, but it was inhibitory toNeisseria gonorrhoeae. Decreasing the concentration of Tween 80, ammonium citrate, and sodium acetate to one-tenth of their original concentrations yielded a modified MRS medium which still supported good growth of the lactobacilli and was no longer inhibitory to the gonococci. While GC medium did not allow any detection of the production of antigonococcal activity by the lactobacilli, both modified MRS and DSA media allowed the detection of this activity by the agar overlay technique. The use of modified MRS medium is recommended since it is less selective than DSA medium for the growth of lactobacilli.     

Neurotensin Regulation of Endogenous Acetylcholine Release from Rat Striatal Slices Is Independent of Dopaminergic Tone

The effects of neurotensin (NT) alone or in combination with the dopamine antagonist sulpiride were tested on the release of endogenous acetylcholine (ACh) from striatal slices. NT enhanced potassium (25 mM)-evoked ACh release from striatal slices in a dose-dependent manner. This effect was tetrodotoxin-insensitive, suggesting an action directly on cholinergic elements. The dopamine antagonist sulpiride (5 x 10(-5) M) significantly increased (63%) potassium-evoked ACh release from striatal slices; potassium-evoked ACh release was further increased (90%) in the presence of NT (10(-5) M) and sulpiride (5 x 10(-5) M). The second set of experiments tested the effects of 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra on NT-induced increases of potassium-evoked ACh release. These lesions did not alter the NT regulation of potassium-evoked ACh release from striatal slices, but did significantly increase spontaneous (33%) and potassium-evoked (40%) ACh release from striatal slices. Striatal choline acetyltransferase activity was not affected by 6-OHDA lesions. In addition, following 6-OHDA lesions, sulpiride was ineffective in altering ACh release from striatal slices. Furthermore, evoked ACh release in the presence of the combination of NT and sulpiride was not different from that in the presence of NT alone. These results suggest that in the rat striatum, NT regulates cholinergic interneuron activity by interacting with NT receptors associated with cholinergic elements. Moreover, the NT modulation of cholinergic activity is independent of either an interaction of NT with D2 dopamine receptors or the sustained release of dopamine.     

Preliminary characterization of inhibitors of Neisseria gonorrhoeae produced in vitro by Eubacterium limosum

Among anaerobic bacteria normally found in the urogenital flora, Eubacterium limosum was found to inhibit the in vitro growth of Neisseria gonorrhoeae. The antigonococcal activity produced by E. limosum was soluble in methanol and in a chloroform--methanol mixture (30:70). The fraction soluble in chloroform--methanol (30:70) yielded eight absorbance peaks when chromatographed on Bio-Gel P-2 and the inhibitory activity was found in the first two peaks. This activity was not absorbed on DEAE Sephacel and was eluted with distilled water in a peak considered as peak 1, on which preliminary characterization was done. The inhibitory activity of peak 1 was found to be heat and pH resistant and not susceptible to proteases, lipase, or amylases. When peak 1 was chromatographed on cellulose paper using a butanol--acetic acid (4:1) solvent system, eight different spots were detected upon spraying the paper with ninhydrin. No spot was detected with anthrone, bromothymol, nor Sudan black reagents used for the detection of carbohydrates and lipids. Based on sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis and gel chromatography on Sephadex G-25, peak 1 appeared either as a diffuse band and as a single peak, respectively. The molecular weight of the inhibitory complex was estimated to be 2400. All these results suggest that the antigonococcal activity produced by E. limosum is composed of more than one low molecular weight amino compound.