Filogenetica dei batteri lattici /phylogenetic relationship between LABs using tuf gene
Durante uno nostro studio di applicazione del lievito madre nelle produzioni da forno di tipo dolce, abbiamo usato un lievito acido liofilizzato in commercio (a base di L. brevis, e lieviti). Dopo le prime propagazioni, siamo passati dalla pasta per il pane a quella di tipo dolce contenente uova. In una analisi successiva, abbiamo trovato, oltre al Lactobacillus brevis, anche il Lactobacillus coryniformis. Questo dimostra come l'adattamento ad un ambiente o substrato alimentare permette, ossia induce, la crescita e la convivenza di più ceppi diversi insieme.
Nel laboratorio dell'ISPA-CNR di Lecce, abbiamo sequenziato il DNA del gene tuf (elongation factor Tu) in specie di Batteri Lattici in cui tale gene non era stato ancora studiato.
Il progetto Barcoding of life si pone l'obiettivo di identificare per ogni specie vivente una sequenza unica di DNA in grado di fornire un tag specifico/impronta digitale di riconoscimento
Come conseguenza di questo lavoro di raccolta di dati, si possono creare alberi filogenetici che rappresentano le relazioni di imparentamento, filogenetiche, tra le specie. Inoltre, è possibile individuare anche differenze tra ceppi e ottenere una identificazione basata sul loro DNA peculiare.Lactic acid bacteria are a great resource of biodiversity. Many strains of the same species show adaptaded growth conditions to specific substrates. Probiotic strains can grow in the gut, for example, interacting with other bacteria and with the gut cell surface and mucins. Lactobacilli are responsible of many food productions, cheese-making, fermentation of vegetables (sauerkraut, olives), pickle production, and fermented silage storage. Lactic acid, lowering th pH, preserves the food for long periods by the combined action of acidity and salt.
During a study on bread and baked products made using sourdough, we started from a liophilised sourdough mixture marketed by a company, based on L. brevis and Candida natural yeasts. After changing substrate, from wheat flour to wheat added with sugar and eggs to produce baked sweet cakes, we found that, in addition to the previous L. brevis strain, a natural strain of L. coryniformis was present, grown together with the other strain. L. coryniformis is not usually reported in acid sourdoughs. This finding shows how the change in substrates and in environment has subtle consequences on the change in strains and on their cooperativity.
In our lab at ISPA-CNR in Lecce, we partially sequenced the tuf gene in LAB species whose tuf sequences were still unknown. This was to provide new barcodes for species identification and for making phylogenetic trees within the Lactobacillus genus.
The CONSORTIUM FOR THE BARCODE OF LIFE (CBOL) is an international collaboration http://barcoding.si.edu/
BARCODE OF LIFE: A short DNA sequence, from a uniform locality on the genome, used for identifying species.
Lactobacillus tree obtained using tuf sequences, made using Bioedit and MEGA softwares, using the Lactococcus tuf sequence as reference.
Blaiotta G and Fusco V from their work obtaiend a phylogentic tree of LAB species based on chaperonin Hsp60. In: Lactobacillus strain diversity based on partial hsp60 gene sequences and design of PCR-restriction fragment length polymorphism assays for species identification and differentiation. Appl Environ Microbiol. 2008 74(1):208-15)Our conclusion is that it is possible to superimpose the three informations (16S rDNA, tuf and GroEL/Hsp60) and all of them are concordant.
Tuf sequences however provide high specific barcodes useful for indentification fo strains also at sub-species level.
Nel laboratorio dell'ISPA-CNR di Lecce, abbiamo sequenziato il DNA del gene tuf (elongation factor Tu) in specie di Batteri Lattici in cui tale gene non era stato ancora studiato.
Il progetto Barcoding of life si pone l'obiettivo di identificare per ogni specie vivente una sequenza unica di DNA in grado di fornire un tag specifico/impronta digitale di riconoscimento
Come conseguenza di questo lavoro di raccolta di dati, si possono creare alberi filogenetici che rappresentano le relazioni di imparentamento, filogenetiche, tra le specie. Inoltre, è possibile individuare anche differenze tra ceppi e ottenere una identificazione basata sul loro DNA peculiare.Lactic acid bacteria are a great resource of biodiversity. Many strains of the same species show adaptaded growth conditions to specific substrates. Probiotic strains can grow in the gut, for example, interacting with other bacteria and with the gut cell surface and mucins. Lactobacilli are responsible of many food productions, cheese-making, fermentation of vegetables (sauerkraut, olives), pickle production, and fermented silage storage. Lactic acid, lowering th pH, preserves the food for long periods by the combined action of acidity and salt.
During a study on bread and baked products made using sourdough, we started from a liophilised sourdough mixture marketed by a company, based on L. brevis and Candida natural yeasts. After changing substrate, from wheat flour to wheat added with sugar and eggs to produce baked sweet cakes, we found that, in addition to the previous L. brevis strain, a natural strain of L. coryniformis was present, grown together with the other strain. L. coryniformis is not usually reported in acid sourdoughs. This finding shows how the change in substrates and in environment has subtle consequences on the change in strains and on their cooperativity.
In our lab at ISPA-CNR in Lecce, we partially sequenced the tuf gene in LAB species whose tuf sequences were still unknown. This was to provide new barcodes for species identification and for making phylogenetic trees within the Lactobacillus genus.
The CONSORTIUM FOR THE BARCODE OF LIFE (CBOL) is an international collaboration http://barcoding.si.edu/
BARCODE OF LIFE: A short DNA sequence, from a uniform locality on the genome, used for identifying species.
Lactobacillus tree obtained using tuf sequences, made using Bioedit and MEGA softwares, using the Lactococcus tuf sequence as reference.Blaiotta G and Fusco V from their work obtaiend a phylogentic tree of LAB species based on chaperonin Hsp60. In: Lactobacillus strain diversity based on partial hsp60 gene sequences and design of PCR-restriction fragment length polymorphism assays for species identification and differentiation. Appl Environ Microbiol. 2008 74(1):208-15)Our conclusion is that it is possible to superimpose the three informations (16S rDNA, tuf and GroEL/Hsp60) and all of them are concordant.
Tuf sequences however provide high specific barcodes useful for indentification fo strains also at sub-species level.
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