Indoor moulds in asthmatic patients homes

Summary A study was conducted in 29 households with asthmatic patients in order to analyse the indoor mould concentration; an important contamination was found in both the air and the dust. Although it is known that the outdoor mould concentration in the air decreases during winter, we found that the indoor one did not vary throughout the year. Moreover, the indoor mould concentration increased during the winter in recently built houses, probably because of the poor ventilation. The immunological study showed a lack of correlation between the moulds collected and the patients sensitization.     

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.     

Fingerprint Patterns in Huntington's Chorea and Parkinson's Disease

In the course of a continuing search for means of predicting Huntington''s chorea before the onset of neurological symptoms, a study of fingerprint patterns was undertaken, using the technique employed by Hodges and Simon in the investigation of patients with Wilson''s disease. Fingerprint patterns of 61 patients with Huntington''s chorea and 50 with Parkinson''s disease were compared with norms established by Scotland Yard. Although an increased incidence of the “whorl” pattern was seen in the left second and third fingers in patients with Huntington''s chorea, this finding could not be interpreted as having diagnostic or prognostic value as it was found also in some normal subjects and in occasional cases of Parkinson''s disease. The pattern supposedly characteristic of Wilson''s disease was also seen in persons with Huntington''s chorea.     

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.     

In vitro and in vivo neurotoxicity of prion protein oligomers

The mechanisms underlying prion-linked neurodegeneration remain to be elucidated, despite several recent advances in this field. Herein, we show that soluble, low molecular weight oligomers of the full-length prion protein (PrP), which possess characteristics of PrP to PrPsc conversion intermediates such as partial protease resistance, are neurotoxic in vitro on primary cultures of neurons and in vivo after subcortical stereotaxic injection. Monomeric PrP was not toxic. Insoluble, fibrillar forms of PrP exhibited no toxicity in vitro and were less toxic than their oligomeric counterparts in vivo. The toxicity was independent of PrP expression in the neurons both in vitro and in vivo for the PrP oligomers and in vivo for the PrP fibrils. Rescue experiments with antibodies showed that the exposure of the hydrophobic stretch of PrP at the oligomeric surface was necessary for toxicity. This study identifies toxic PrP species in vivo. It shows that PrP-induced neurodegeneration shares common mechanisms with other brain amyloidoses like Alzheimer disease and opens new avenues for neuroprotective intervention strategies of prion diseases targeting PrP oligomers.     

An organelle proteomic method to study neurotransmission-related proteins, applied to a neurodevelopmental model of schizophrenia

Limited information is currently available on molecular events that underlie schizophrenia-like behaviors in animal models. Accordingly, we developed an organelle proteomic approach enabling the study of neurotransmission-related proteins in the prefrontal cortex (PFC) of postpubertal (postnatal day 60 (PD60)) neonatally ventral hippocampal (nVH) lesioned rats, an extensively used neurodevelopmental model of schizophrenia-like behaviors. The PFC was chosen because of its purported role in the etiology of the disease. Statistical analysis of 392 reproducible spots on 2-D organelle proteomic patterns revealed significant changes in intensity of 18 proteinous spots in plasma membrane-enriched fractions obtained from postpubertal nVH lesioned rats compared to controls. Mass spectrometric analysis and database searching allowed the identification of a single protein in each of the nine differential spots, including proteins of low abundance, such as neurocalcin delta. Most of the identified dysregulated proteins, including clathrin light chain B, syntaxin binding protein 1b and visinin-like protein 1 are known to be linked to various neurotransmitter systems and to play key roles in plasma membrane receptor expression and recycling as well as synaptic vesicle exocytosis/recycling. Organelle proteomic approaches have hence proved to be most useful to identify key proteins linked to a given behavior in animal models of brain diseases.     

Nucleotide analogs and molecular modeling studies reveal key interactions involved in substrate recognition by the yeast RNA triphosphatase

RNA triphosphatases (RTPases) are involved in the addition of the distinctive cap structure found at the 5′ ends of eukaryotic mRNAs. Fungi, protozoa and some DNA viruses possess an RTPase that belongs to the triphosphate tunnel metalloenzyme family of enzymes that can also hydrolyze nucleoside triphosphates. Previous crystallization studies revealed that the phosphohydrolase catalytic core is located in a hydrophilic tunnel composed of antiparallel β-strands. However, all past efforts to obtain structural information on the interaction between RTPases and their substrates were unsuccessful. In the present study, we used computational molecular docking to model the binding of a nucleotide substrate into the yeast RTPase active site. In order to confirm the docking model and to gain additional insights into the molecular determinants involved in substrate recognition, we also evaluated both the phosphohydrolysis and the inhibitory potential of an important number of nucleotide analogs. Our study highlights the importance of specific amino acids for the binding of the sugar, base and triphosphate moieties of the nucleotide substrate, and reveals both the structural flexibility and complexity of the active site. These data illustrate the functional features required for the interaction of an RTPase with a ligand and pave the way to the use of nucleotide analogs as potential inhibitors of RTPases of pathogenic importance.     

Atmospheric pressure chemical ionization-mass spectrometry method to improve the determination of dansylated polyamines

Determination of polyamine pools is still a step impossible to circumvent in studies aimed at determining the pathophysiological role of natural polyamines. In addition, polyamine measurement in biological fluids and tissues may have clinical relevance, especially in cancer patients. Among the wide panel of analytical methods developed for the quantification of polyamines, high-performance liquid chromatographic (HPLC) separation of polyamines after derivatization with dansyl chloride remains the most commonly used method. In this work, we show that atmospheric pressure chemical ionization-mass spectrometry (MS) can be used to detect and quantify biologically relevant polyamines after dansylation, without chromatographic separation. Positive-ion mass spectra for each dansylated polyamine were generated after optimization by flow injection analysis (FIA). FIA coupled with MS detection by selected ion monitoring greatly increased the sensitivity of the polyamine detection. The method is linear over a wide range of polyamine concentrations and allows detection of quantities as low as 5 fmol. The FIA/MS method is about 50-fold more sensitive than the conventional HPLC/fluorimetry procedure. A good correlation (r>0.98) between these two methods was observed. The FIA/MS method notably reduces the time of analysis per sample to 1.5 min and turns out to be rapid, efficient, cost saving, reproducible, and sufficiently simple to allow its routine application.