A novel application of capnography during controlled human exposure to air pollution

BACKGROUND: The objective was to determine the repeatability and stability of capnography interfaced with human exposure facility. METHODS: Capnographic wave signals were obtained from five healthy volunteers exposed to particle-free, filtered air during two consecutive 5 min intervals, 10 min apart, within the open and then the sealed and operational human exposure facility (HEF). Using a customized setup comprised of the Oridion Microcap(® )portable capnograph, DA converter and AD card, the signal was acquired and saved as an ASCII file for subsequent processing. The minute ventilation (VE), respiratory rate (RR) and expiratory tidal volume (V(TE)) were recorded before and after capnographic recording and then averaged. Each capnographic tracing was analyzed for acceptable waves. From each recorded interval, 8 to 19 acceptable waves were selected and measured. The following wave parameters were obtained: total length and length of phase II and III, slope of phase II and III, area under the curve and area under phase III. In addition, we recorded signal measures including the mean, standard deviation, mode, minimum, maximum – which equals end-tidal CO(2 )(EtCO(2)), zero-corrected maximum and true RMS. RESULTS: Statistical analysis using a paired t-test for means showed no statistically significant changes of any wave parameters and wave signal measures, corrected for RR and V(TE), comparing the measures when the HEF was open vs. sealed and operational. The coefficients of variation of the zero-corrected and uncorrected EtCO(2), phase II absolute difference, signal mean, standard deviation and RMS were less than 10% despite a sub-atmospheric barometric pressure, and slightly higher temperature and relative humidity within the HEF when operational. CONCLUSION: We showed that a customized setup for the acquisition and processing of the capnographic wave signal, interfaced with HEF was stable and repeatable. Thus, we expect that analysis of capnographic waves in controlled human air pollution exposure studies is a feasible tool for characterization of cardio-pulmonary effects of such exposures

The role of genotype and phenotype in the infraspecific taxonomy of Lactobacillus species.

Data recently obtained for two infraspecific groups within the species Lactobacillus delbrueckii and Lactobacillus plantarum led to the description of two novel subspecies: Lactobacillus delbrueckii subsp. indicus (Dellaglio et al., 2005) and Lactobacillus plantarum subsp. argentoratensis (Bringel et al., in press), respectively. Subspecies are the lowest taxonomic ranks with standing in nomenclature and are based on the recognition of phenotypic and/or genotypic heterogeneities (Rossell\uf3-Mora & Amann, 2001). The descriptions of the aforementioned subspecies were the result of a polyphasic approach. It allowed to highlight that, in both species, the genotypic/genomic diversity was more marked than the phenotypic one. Moreover, in the case of L. delbrueckii, the phenotypic similarity between two subspecies was due to a phenomenon of convergent evolution: two different genetic equipments were responsible of the same phenotypic manifestation (Germond et al., 2003). On the basis of those results, we present some considerations on the contribution that phenotypic and genotypic/genomic data may give to the delineation of subspecies. The experimental results presented make us suggest that prominent role in infraspecific taxonomy should be given to genotype since laboratory conditions could be misleading in the evaluation of \u201cin vivo\u201d expressed traits (phenotype) and, most of all, genotypic/genomic analysis is fundamental to understand which potentialities an organism could express

Technological and genetic aspects of Lactobacillus delbrueckii subsp. indicus involved in the production of novel fermented milks.

Four Lactobacillus strains isolated from an Indian fermented milk have recently been grouped in the new subspecies L. delbrueckii subsp. indicus (1). Previous studies have evidenced that these strains ferment lactose constitutively, like L. delbrueckii subsp. bulgaricus (1). However, lactose degradation is probably related to the presence of a peculiar genetic equipment since any amplification of the lac operon genes was achieved. No additional information is currently available on technological and genetic properties of these strains. In the present study, the ability of the four Indian strains to induce pleasant organoleptic traits when grown in milk-based media of different composition was investigated. Physical and chemical parameters were monitored during milk fermentation in order to establish the performances of the examined strains. In addition, sequences of genes encoding some lactose-PTS system components were obtained suggesting that lactose degradation in the Indian strains is probably due to the presence of these genetic determinants. Finally, a comparison of technological and genetic characteristics displayed by the different L. delbrueckii subspecies was conducted. The data obtained indicate that L. delbrueckii subsp. indicus strains show interesting properties and may be applied in association with S. thermophilus for the production of novel fermented milks

Lactobacillus delbrueckii subsp. indicus subsp. nov., isolated from Indian dairy products

Four strains isolated from Indian dairy products and initially identified as Lactobacillus delbrueckii could not be assigned to a definite subspecies because molecular identification and phenotypic traits did not agree with those of recognized subspecies of L. delbrueckii. Hybridization of total DNA (78-86% against type strains of the other three subspecies), AFLP and RAPD-PCR fingerprints, phylogenetic analysis based on 16S rRNA gene sequences and sequence analysis of two coding genes (recA and hsp60), together with phenotypic profiles, indicated that the four strains form a coherent cluster and represent a novel subspecies, for which the name Lactobacillus delbrueckii subsp. indicus subsp. nov. is proposed. The type strain is NCC725T (=LMG 22083T=DSM 15996T)

Description of Lactobacillus delbrueckii subsp. indicus, a novel subspecies grouping strains isolated from Indian yogurt.

Four strains isolated from Indian fermented milks were identified as Lactobacillus delbrueckii, however molecular identification and phenotypic traits did not agree with those of recognized subspecies of L. delbrueckii. Techniques applied for a first characterization of strains were ribotyping, IS typing, ARDRA, analysis of expression of genes prtB (encoding for a cell-wall anchored protease) and galT (responsible for the degradation of galactose), determination of the ISL6 in the genomes. Those investigations were integrated with AFLP and RAPD-PCR fingerprints, phylogenetic analysis based on 16S rRNA gene sequences, sequence analysis of two protein-coding genes (recA and hsp60), fermentation profiles and finally, hybridization of total DNA. Data collected indicated that the four strains form a coherent cluster and represent a novel subspecies, for which the name Lactobacillus delbrueckii subsp. indicus subsp. nov. has been validly published

Growth in milk: a challenging task for strains of the species Lactobacillus delbrueckii.

The ability of lactic acid bacteria (LAB) to grow in milk is a consequence of the presence and expression of genes responsible for the degradation of milk sugars and casein. The genes coding for the utilization of lactose and galactose (the main sugars of milk) are organized into the lac and gal operons, respectively. The genetic equipment involved in the proteolytic activity of LAB in milk is complex and still not well characterized. The aim of this research was to investigate some genetic determinants implicated in the catabolism of lactose, galactose and casein in the four known subspecies of L. delbrueckii, i.e. the subspecies delbrueckii, bulgaricus, lactis, and indicus. In particular some aspects were examined: the expression of the lacZ gene, encoding the \u3b2-galactosidase enzyme; the sequence of lacR gene and the presence of galT gene, encoding the galactosyl-1-phosphate uridyl transferase. In addition, the presence of the gene prtB, encoding a cell-wall anchored protease, was evaluated and associated with the ability to grow in milk. Differences in the distribution and/or regulation of these genes among the four subspecies of L. delbrueckii, were underlined and related to their adaptation to specific ecological niches