Calorimetric measurement of free energy utilization by Nitrosomonas and Nitrobacter

Summary Calorimetric estimates of the utilization efficiency of the free-energy derived from substrate oxidation by cell suspensions of two nitrifying bacteria, Nitrosomonas and Nitrobacter, provided two ranges of values: 11 to 27% and 15 to 51%, respectively. About 15 to 30% of the utilized free-energy is used for driving endergonic reactions other than CO₂ fixation, probably the synthesis of polyphosphates.The molar heat of substrate oxidation does not seem to be influenced by the age of cells harvested during growth or by the length of the incubation period during which cells have been kept in a buffer suspension in a starved condition. The loss of respiratory activity measured either by oxygen uptake or heat evolution in the presence of the specific substrate, nitrite or ammonium, decreases according to kinetics which are influenced by the aerobiosis of the suspension. The viability of the starved cells decreases in a way which is similar to that of the respiratory activity. It seemed impossible to obtain cells which had lost their viability but kept the ability to oxidize their substrate.Two inhibitors of the respiratory chain, quinacrine and cyanide, are without effect on the molar heat of substrate oxidation and consequently on the free-energy utilization efficiency. 2.4 dinitrophenol did decrease the rate of heat evolution during substrate oxidation at concentrations at which the rate of oxygen uptake was not depressed, with the consequences that free-energy efficiency was apparently increased.     

Interleukin-1 beta increases the BCL-2/BAX ratio in Kaposi's sarcoma cells

Interleukin-1 (IL-1) is a multifunctional cytokine known to act as a growth factor for AIDS-KS cells. In addition to its mitogenic effects, we found that IL-1 induced the protection of KS cells from apoptotic death induced by serum deprivation in a dose-dependent manner. AIDS-KS cells as well as cells derived from iatrogenic and sporadic KS exhibited a similar response to IL-1, which stresses the key role of this cytokine in the pathogenesis of KS regardless of its epidemiological form. Using both an immunohistochemical and an immunoblot approach, we found that IL-1 increased the expression of Bcl-2 and decreased that of Bax, while having no effect on the expression of Bclx(L), Fas and CD40. The effects of IL-1 were inhibited by IL-1ra, suggesting that imbalance between these two counter-acting cytokines may contribute to the altered accumulation of KS spindle cells. Our findings may provide a link between KS cell escape from apoptosis and the immune dysregulation known to be associated with KS.     

A rapid and sensitive method for the analysis of brain monoamine neurotransmitters using ultra-fast liquid chromatography coupled to electrochemical detection

Electrochemical detection is often used to detect catecholamines and indolamines in brain samples that have been separated by conventional reverse-phase high performance liquid chromatography (HPLC). This paper presents the transfer of an existing chromatographic method for the determination of monoamines in brain tissues using 5 μm granulometry HPLC columns to columns with a particle diameter less than 3 μm. Several parameters (repeatability, linearity, accuracy, limit of detection, and stability of samples) for this new ultrafast high performance liquid chromatography (UHPLC) method were examined after optimization of the analytical conditions. The separation of seven compounds, noradrenaline, dopamine and three of its metabolites, dihydroxyphenylacetic acid, homovanillic acid, and 3-methoxytyramine, and serotonin and its metabolite, 5-hydroxyindole-3-acetic acid was analyzed using this UHPLC-electrochemical detection method. The final method, which was applied to brain tissue extracts from mice, rats, and cats, decreased analysis time by a factor of 4 compared to HPLC, while guaranteeing good analytical performance.     

Development of two PCR assays for the identification of mycoplasmas causing contagious agalactia

Abstract A new detection test for the mycoplasmas causing contagious agalactia, Mycoplasma agalactiae , M. capricolum subsp. capricolum and M. mycoides subsp. mycoldes L.C., was developed. It was based on two polymerase chain reaction assays: the Ma-PCR for the detection of M. agalactiae and the MYC-PCR for the 'mycoides cluster' thus including M. capricolum subsp. capricolum and M. mycoides subsp. mycoides L.C. An M. agalactiae strain was identified by a 933-bp Ma-PCR product and no amplification with the MYC-PCR. In contrast, a 460-bp MYC-PCR product and a negative or a 350-bp Ma-PCR product characterized a 'mycoides cluster' strain. M. capricolum subsp. capricolum and M. mycoides subsp. mycoides L.C. were identified by their species-specific Asel pattern of the 460-bp MYC-PCR product.     

Rapid method for enumeration of viable Legionella pneumophila and other Legionella spp. in water

A sensitive and specific method has been developed to enumerate viable L. pneumophila and other Legionella spp. in water by epifluorescence microscopy in a short period of time (a few hours). This method allows the quantification of L. pneumophila or other Legionella spp. as well as the discrimination between viable and nonviable Legionella. It simultaneously combines the specific detection of Legionella cells using antibodies and a bacterial viability marker (ChemChrome V6), the enumeration being achieved by epifluorescence microscopy. The performance of this immunological double-staining (IDS) method was investigated in 38 natural filterable water samples from different aquatic sources, and the viable Legionella counts were compared with those obtained by the standard culture method. The recovery rate of the IDS method is similar to, or higher than, that of the conventional culture method. Under our experimental conditions, the limit of detection of the IDS method was <176 Legionella cells per liter. The examination of several samples in duplicates for the presence of L. pneumophila and other Legionella spp. indicated that the IDS method exhibits an excellent intralaboratory reproducibility, better than that of the standard culture method. This immunological approach allows rapid measurements in emergency situations, such as monitoring the efficacy of disinfection shock treatments. Although its field of application is as yet limited to filterable waters, the double-staining method may be an interesting alternative (not equivalent) to the conventional standard culture methods for enumerating viable Legionella when rapid detection is required.     

Rapid Method for Enumeration of Viable Legionella pneumophila and Other Legionella spp. in Water

A sensitive and specific method has been developed to enumerate viable L. pneumophila and other Legionella spp. in water by epifluorescence microscopy in a short period of time (a few hours). This method allows the quantification of L. pneumophila or other Legionella spp. as well as the discrimination between viable and nonviable Legionella. It simultaneously combines the specific detection of Legionella cells using antibodies and a bacterial viability marker (ChemChrome V6), the enumeration being achieved by epifluorescence microscopy. The performance of this immunological double-staining (IDS) method was investigated in 38 natural filterable water samples from different aquatic sources, and the viable Legionella counts were compared with those obtained by the standard culture method. The recovery rate of the IDS method is similar to, or higher than, that of the conventional culture method. Under our experimental conditions, the limit of detection of the IDS method was <176 Legionella cells per liter. The examination of several samples in duplicates for the presence of L. pneumophila and other Legionella spp. indicated that the IDS method exhibits an excellent intralaboratory reproducibility, better than that of the standard culture method. This immunological approach allows rapid measurements in emergency situations, such as monitoring the efficacy of disinfection shock treatments. Although its field of application is as yet limited to filterable waters, the double-staining method may be an interesting alternative (not equivalent) to the conventional standard culture methods for enumerating viable Legionella when rapid detection is required.     

Keratine unguéale et parasites fungiques

Sans résuméCommunication présentée au Congrès Int. de Dermatologie Tropicale, Naples, 8–13 juin 1964.     

Étude du Métabolisme D'acides Aminés ChezAspergillus oryzae

Résumé Lorsque l'on cultiveAspergillus oryzae w.f. sur une solution de substitution contenant un des acides aminés suivants: glycine, alanine, sérine, acide aspartique, thréonine, valine leucine, isoleucine, proline, hydroxyproline, arginine, ornithine et citrulline, on retrouve toujours à l'état libre dans son mycélium de l'acide glutamique et de l'alanine; on y décèle presque toujours la glutamine et l'acide aspartique. Par contre on n'y rencontre jamais, à moins que par simple diffusion, ou bien encore rarement, la glycine, la thréonine, la leucine, l'isoleucine, l'hydroxyproline et la citrulline. Quant à l'acide γ-aminobutyrique, il ne se décèle que dans le mycélium cultivé aux dépens de thréonine, de valine, de leucine, d'isoleucine, d'arginine, de citrulline et d'ornithine. Enfin, lorsque l'on prend une solution d'ornithine comme liquide de substitution on constate la présence dans le mycélium d'une substance aminée non identifiée. Ces diverses observations attribuent aux réactions de transamination, qui donnent lieu à la formation d'acide glutamique, d'alanine et d'acide aspartique, un r?le central dans le métabolisme ternaire et quaternaire de la moisissure étudiée.