J. Breton

New highly divergent rRNA sequence among biodiverse genotypes of Enterocytozoon bieneusi strains isolated from humans in Gabon and Cameroon.

ABSTRACT Intestinal microsporidiosis due to Enterocytozoon bieneusi is a leading cause of chronic diarrhea in severely immunocompromised human immunodeficiency virus (HIV)-positive patients. It may be a public health problem in Africa due to the magnitude of the HIV pandemic and to poor sanitary conditions. We designed two prevalence studies of E. bieneusi in Central Africa, the first with HIV-positive patients from an urban setting in Gabon and the second with a nonselected rural population in Cameroon. Stool samples were analyzed by an immunofluorescence antibody test and PCR. Twenty-five out of 822 HIV-positive patients from Gabon and 22 out of 758 villagers from Cameroon were found to be positive for E. bieneusi. The prevalence rates of the two studies were surprisingly similar (3.0% and 2.9%). Genotypic analysis of the internal transcribed spacer region of the rRNA gene showed a high degree of diversity in samples from both countries. In Gabon, 15 isolates showed seven different genotypes: the previously reported genotypes A, D, and K along with four new genotypes, referred to as CAF1, CAF2, CAF3, and CAF4. In Cameroon, five genotypes were found in 20 isolates: the known genotypes A, B, D, and K and the new genotype CAF4. Genotypes A and CAF4 predominated in Cameroon, whereas K, CAF4, and CAF1 were more frequent in Gabon, suggesting that different genotypes present differing risks of infection associated with immune status and living conditions. Phylogenetic analysis of the new genotype CAF4, identified in both HIV-negative and HIV-positive subjects, indicates that it represents a highly divergent strain.

Genotype identification of Enterocytozoon bieneusi isolates from stool samples of HIV-infected Tunisian patients.

The microsporidian species Enterocytozoon bieneusi is a major cause of chronic diarrhea and malabsorption in patients with AIDS. Genotyping was performed on seven E. bieneusi strains for the first time in Tunisia. All the strains were isolated from stool samples of humans with immunodeficiency virus (HIV) infection. Analysis of the ribosomal RNA gene internal transcribed spacer (rDNA ITS) allowed the identification of three distinct genotypes previously described in other studies. Genotypes D and B were characterized in four and two respectively. The Peruvian genotype (Peru 8) was detected in the last isolate. These results indicate a genetic diversity in E. bieneusi strains from HIV Tunisian patients and suggest the coexistence of both zoonotic and anthroponotic route of transmission.

Low resolution VUV absorption spectrum of boron monoxide

The absorption spectrum of BO has been recorded between 2400 and 300 Å on the SA61 beam line of SUPERACO in Orsay. A new electronic transition has been observed and vibrationally analysed. Nine Rydberg states have been observed and classified into Rydberg series giving two ionization limits at 12.849eV for the X 1Σ+ ionic state and at 13.117eV for the A 1II state of BO+. Two ionization limits have been observed at 754 and 374 Å. The first of these corresponds to the B 1Σ+ state and the last one to the C 1Σ+ state of BO+. The new results are compared with the ab initio calculations of Karna and Grein concerning BO and BO+. The agreement is satisfactory.

The absorption spectrum of diatomic calcium between 120 and 20 nm

The vacuum ultraviolet absorption spectrum of Ca2 has been extended down to 20 nm by using the same techniques as those described by Nzohabonayo et al. [2003, Molec. Phys., 101, 2917]. All the new states observed are Rydberg states giving three new ionization limits at 13.76 eV, 17.99 eV and a third one higher than 33 eV.

The vacuum ultraviolet absorption spectrum of diatomic calcium

Calcium granules (99.5%) have been heated to 615°C in a tantalum furnace and the absorption spectrum has been observed on the SA 61 beam line of SUFERACO (Orsay) using a 3-metre Balzers monochromator down to the -LiF cut-off (1015 Å). An intense Rydberg series has been observed between 1900 and 1500 Å. This series extends from n = 5 to n = 12 and gives the ionization potential at 63068 cm−1 (1585.6 Å) or 7.819eV and the quantum defect δ = 1.73.

THE VUV ABSORPTION-SPECTRUM OF THE SIF FREE-RADICAL

Abstract The absorption spectrum of SiF has been observed down to the LiF absorption limit. Rydberg series nsσ npσ , and npπ have been observed up to n = 15, as well as two superexcited states.