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

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

Monitoring the water resources in the large railway projects: The fortezza – ponte gardena case study, Southern Brenner Base Tunnel access

The Brenner Base Tunnel (BBT) is being built to connect Italy and Austria running from Fortezza to Innsbruck (55km). The southern access will link Ponte Gardena with Fortezza. As widely known, underground tunneling works may have significant impact on regional hydrogeological systems, causing a drawdown of water levels and a decrease of springs’ discharge rates. Therefore, an extended monitoring of water resources can be crucial to define the possible interference between the tunneling and the surrounding environment. The analysis presented in this paper allowed to determine the main hydrogeological regime, characterizing this portion of the Isarco valley. The hydro-chemical analysis improved the knowledge of groundwater paths, mainly characterized by low-mineralized flows, running within the shallow portion of the rock mass or in correspondence of quaternary glacial deposits and not related to the deep-water network. Finally, isotopic correlations between rain and underground water have confirmed this hydrogeological layout

Variability of physical attributes in tropical weathered soil cultivated with irrigated beans (Phaseolus vulgaris L.)

Soil physical attributes are affected by several events. The ability to identify the variation of those attributes can be used to decide the best crop management. Although it is known that smaller grids are more representative, predicting the least number of points while maintaining accuracy is a tool that might reflect a gain in yield and time. The aims of this study were to evaluate the spatial physical variability and to define the minimum sampling density in a tropical Typic Haplustults soil using a scaled semivariogram in a central pivot area with pinto bean (Phaseolus vulgaris L.) after the eighth bean harvest in Cristalina, Goias State. Soil samples were collected at a regular grid of 10-m intervals, totaling 180 points, and at depths of 0.00-0.10 m, 0.10-0.20 m, and 0.20-0.30 m to determine total sand content (TS), silt (SIL), clay (CL), water-dispersed clay (WDC), mean weight diameter of soil aggregates (MWD), soil penetration resistance (PR), soil macroporosity (Ma), soil microporosity (Mi), and soil bulk density (BD). The results demonstrated that management promoted superficial soil compaction with increasing BD and Mi and decreasing Ma and TP. The scaled semivariogram demonstrated similarity between attributes in the three studied soil layers, evidencing strong spatial dependency. The sample density showed a strong influence of WDC in the irrigated soil properties. Adoption of a scaled semivariogram is a strategy that can be used to determine a minimum number of points that represents the spatial variability of soil physical attributes and to assist the best management in irrigated soils135656661CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQsem informaçã