Prokaryotic Diversity and Distribution in Different Habitats of an Alpine Rock Glacier-Pond System.

Rock glaciers (RG) are assumed to influence the biogeochemistry of downstream ecosystems because of the high ratio of rock:water in those systems, but no studies have considered the effects of a RG inflow on the microbial ecology of sediments in a downstream pond. An alpine RG-pond system, located in the NW Italian Alps has been chosen as a model, and Bacteria and Archaea 16S rRNA genes abundance, distribution and diversity have been assessed by qPCR and Illumina sequencing, coupled with geochemical analyses on sediments collected along a distance gradient from the RG inflow. RG surface material and neighbouring soil have been included in the analysis to better elucidate relationships among different habitats.Our results showed that different habitats harboured different, well-separated microbial assemblages. Across the pond, the main variations in community composition (e.g. Thaumarchaeota and Cyanobacteria relative abundance) and porewater geochemistry (pH, DOC, TDN and NH4+) were not directly linked to RG proximity, but to differences in water depth. Some microbial markers potentially linked to the presence of meltwater inputs from the RG have been recognised, although the RG seems to have a greater influence on the pond microbial communities due to its contribution in terms of sedimentary material.

Modelling Biolog profiles' evolution for yeast growth monitoring in alcoholic fermentation.

AIMS: A research was undertaken to explore the possibility to express with suitable mathematical models Biolog metabolic curves obtained for oenological yeasts and to use such models for monitoring yeast growth in alcoholic fermentation. METHODS AND RESULTS: Experimental curves of metabolic activity in Biolog YT microplates, obtained in a previous work for various oenological yeast strains in pure cultures and mixed populations, at various cell concentrations, have been modelled with Gompertz's, Gompertz's modified and Lindstrom's mathematical equations. Lindstrom's model proved to be the most suitable to fit the curves of the oenological yeasts under study, providing the highest correlation coefficients between experimental and calculated data. The model made it possible to recognize, in mixed yeast populations, the presence of active dry yeasts used for guided fermentations. Model's constant parameters were used for a numerical characterization of yeast curves. CONCLUSIONS: The application of the model to the experimental data resulted to be suitable for an early prediction of the successive evolution of yeast growth. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained indicate the possibility to develop protocols for monitoring yeast presence during alcoholic fermentation, with an early assessment of the correct evolution of their growth, especially when active dry yeasts are employed.

Evaluation of the effectiveness of BCG vaccination using the case-control method in Buenos Aires, Argentina.

A retrospective case-control study was conducted in Argentina to determine the protection conferred by BCG vaccination against tuberculosis in children under six years of age, in an area where coverage is about 55%. A total of 175 tuberculosis patients were included. Five controls selected from patients treated at the same hospital as those under study for reasons other than tuberculosis were matched to each case on the basis of age, socioeconomic origin, nutritional status and place of residence. Information on BCG vaccination status was collected by an independent examiner. Tuberculosis localizations were as follows: 152 pulmonary, pleural and/or miliary; 18 meningitis; 2 lymphadenitis; 2 osteoarticular; and 1 otic. The diagnosis was based on bacteriological and histopathological tests, computerized tomography, radiology, clinical examination, endoscopy, and proved source of infection. The protective effect of BCG among those who were vaccinated was 73.0% with 95% confidence limits of 82% and 62%. According to these results BCG vaccination given early in life is very effective in preventing tuberculosis.

Effects of substratum on the diversity and stability of ammonia-oxidizing communities in a constructed wetland used for wastewater treatment.

AIM: To study the relationship between the nature of the substratum and the diversity and stability of the ammonia-oxidizing microbial community in a constructed wetland for the treatment of wastewaters. METHODS AND RESULTS: Samples have been taken the year around from sections of the wetland filled with different substrata. When present, the root zones of the helophyte Phragmites australis were also sampled. The diversity of the ammonia-oxidizing community was established by a coupled PCR-DGGE method based on the 16s rRNA gene. Averaged over the seasons, no large differences in community composition were observed between the different substrata, although the section with zeolite always showed the highest frequencies of bands belonging to ammonia-oxidizing bacteria of the beta-subclass of the Proteobacteria. Only sequences related to the Nitrosospira lineage were detected. Averaged again over the seasons, the section with zeolite was also most constant with respect to the potential ammonia-oxidizing activity. CONCLUSIONS: Although the ammonia-oxidizing communities did not differ significantly between the different sections of the constructed wetland, the characteristics of zeolite were most appropriate to accommodate a stable and active community of ammonia-oxidizing bacteria. The presence of the helophyte had no effect on the diversity and stability of the ammonia-oxidizing community. SIGNIFICANCE AND IMPACT OF THE STUDY: It has been shown that substrata used in constructed wetlands made no distinction between ammonia-oxidizing strains in relation to attachment. However, zeolite had the best performance with respect to activity over the seasons.