Application of AFLP fingerprint analysis for studying the biodiversity of Streptococcus thermophilus

Lazzi, Camilla; Bove, Claudio Giorgio; Sgarbi, Elisa; Gatti, Monica; Gioia, Federica La; Torriani, Sandra; Neviani, Erasmo

doi:10.1016/j.mimet.2009.07.021

Cited by 40 publications

(28 citation statements)

References 27 publications

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“…Eighty-three S. thermophilus strains, all (except two) dairy isolates, identified and genotypically differentiated in previous studies (16,24), were screened by consensus PCR with oligonucleotides HIS1-F and HIS1-R (9) made more stringent by changing the annealing temperature to 58°C for 40 s. They were subcultured in M17 broth (Oxoid, Milan, Italy) added with 0.5% (wt/vol) lactose (LM17) at 37°C for 24 h, and total genomic DNA was extracted and purified from 2-ml cultures as described by Rossi et al (26).…”

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confidence: 88%

Quantitative Analysis of Histidine Decarboxylase Gene (hdcA) Transcription and Histamine Production by Streptococcus thermophilus PRI60 under Conditions Relevant to Cheese Making

Rossi

Gardini

Rizzotti

et al. 2011

Appl Environ Microbiol

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This study evaluated the influence of parameters relevant for cheese making on histamine formation by Streptococcus thermophilus. Strains possessing a histidine decarboxylase (hdcA) gene represented 6% of the dairy isolates screened. The most histaminogenic, S. thermophilus PRI60, exhibited in skim milk a high basal level of expression of hdcA, upregulation in the presence of free histidine and salt, and repression after thermization. HdcA activity persisted in cell extracts, indicating that histamine might accumulate after cell lysis in cheese.

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confidence: 88%

Quantitative Analysis of Histidine Decarboxylase Gene (hdcA) Transcription and Histamine Production by Streptococcus thermophilus PRI60 under Conditions Relevant to Cheese Making

Rossi

Gardini

Rizzotti

et al. 2011

Appl Environ Microbiol

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“…Eighty-three S. thermophilus dairy isolates, identified and genotypically characterized in previous studies (12,20), were investigated. All strains were subcultured in LM17 medium, i.e., M17 medium (Fluka, Italy) supplemented with 0.5% (wt/vol) lactose, at 37°C for 24 h. Initially, the strains were screened for tyramine production according to the method of Bover-Cid and Holzapfel (2).…”

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confidence: 99%

Identification of a Tyrosine Decarboxylase Gene ( tdcA ) in Streptococcus thermophilus 1TT45 and Analysis of Its Expression and Tyramine Production in Milk

Gioia

Rizzotti

Rossi

et al. 2011

Appl Environ Microbiol

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In this study, a tyrosine decarboxylase gene (tdcA) was identified in 1 among 83 Streptococcus thermophilus strains tested. Its sequence, nearly identical to that of a tdcA of Lactobacillus curvatus, indicated a horizontal gene transfer event. Transcription in milk and the formation of critical levels of tyramine were observed in the presence of tyrosine.Biogenic amine (BA) formation in fermented food has recently been included by the European Food Safety Authority (EFSA) among the safety concerns requiring evaluation. Among these compounds, tyramine is the most common in ripened cheeses and fermented sausages, where it usually accumulates during ripening and can be present in toxicologically relevant levels (Ͼ100 mg kg Ϫ1 ) (4). The symptoms of tyramine poisoning, also known as "cheese reaction," are hypertension due to peripheral vasoconstriction caused by the release of noradrenaline, pupil dilation, and increased respiration frequency and blood sugar level (22).Tyramine formation is the result of bacterial decarboxylation of tyrosine that is carried out by several microorganisms, including strains of lactic acid bacteria (LAB) belonging to different genera and species (7, 23). Among LAB, Streptococcus thermophilus is of major importance for the dairy industry, where it is commonly used in starter cultures for the manufacture of yogurt, fermented milks, and many varieties of cheese. Recently, a few strains of dairy origin assigned to the species S. thermophilus have been described for their tyraminogenic activity by both physiological assays (15) and consensus PCR on tyrosine decarboxylase genes (tdcA genes) (3). However, the identity of the genetic determinant involved was not unveiled.The aims of this study were (i) to screen the tyramine production of S. thermophilus in synthetic medium, (ii) to identify the gene responsible for this activity, (iii) to quantify its expression by quantitative real-time reverse transcription-PCR (RT-qPCR), and (iv) to monitor the levels of tyramine production in the presence of physicochemical parameters common to a cheese-making process in order to obtain indications on how to limit the formation of this BA.Screening of S. thermophilus strains for tyramine production. Eighty-three S. thermophilus dairy isolates, identified and genotypically characterized in previous studies (12, 20), were investigated. All strains were subcultured in LM17 medium, i.e., M17 medium (Fluka, Italy) supplemented with 0.5% (wt/vol) lactose, at 37°C for 24 h. Initially, the strains were screened for tyramine production according to the method of Bover-Cid and Holzapfel (2). Only the strain S. thermophilus 1TT45 (16S rRNA gene sequence has EMBL/GenBank/DDBJ accession no. FR725449), isolated from Taleggio cheese, gave a positive reaction in plates. Consensus tdcA-targeted PCR with the degenerate primers DEC5/DEC3 (23) on genomic DNA extracted with the method of Rossi et al. (21) from 2-ml cultures generated an amplicon of the expected size of close to 336 bp only from this strain (data not shown). T...

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“…Positive, negative and not significant relationships have been reported between biodiversity and carbon stocks and included unimodal, bell-shaped, u-shaped and or kurtotic distribution (Loreau et al 2001).The increased species richness and proportions of nitrogen-fixing species and species with low leaf mass per unit area increased C storage in mixed-species plantations, whereas increased proportions of large trees and species with high leaf mass per unit area increased tree C storage in natural forests (Ruiz-Jaen & Potvin 2011). The impacts of the characteristics, relative abundance, number and spatial pattern of species are, in principle, all likely to influence C sequestration (Lazzi et al 2009). However, the interaction mechanisms, which attracted the interests of many ecologists, remained unclear.…”

Section: Carbon Stocks and Floristic Diversity Relationshipsmentioning

confidence: 99%

Carbon distribution and its correlation with floristic diversity in subtropical broad-leaved forests during natural succession

Zuo¹,

Ren²,

Weng³

et al. 2017

JTFS

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There are increasing demands for afforestation and reforestation aimed at sequestering carbon (C) and conserving biodiversity. This study provides quantitative results to evaluate C storage capacity and probes the relationship between C distribution of various forest components and their floristic diversity during natural recovery processes. We studied C allocation, total C storage and floristic diversity in a subtropical broad-leaved secondary forest in south-eastern China managed under three different regimes, namely, no logging, early selective logging and late selective logging. Diameter at breast height data from 33 plots were used to construct allometric equations and to evaluate total biomass and C storage. Carbon storage in trees, understorey, necromass and the top 100 cm of soil was responsible for 29.8-47.6%, 0.2-0.5, 2.2-2.7 and 49.9-67.1% of the total C stocks respectively under the three regimes. Tree C stock was positively correlated (Pearson coefficient = 0.35) with tree diversity and explained 12.4% of the overstorey Shannon and Simpson indices. Therefore, elimination of the coniferous species (C. lanceolata) and overstorey diversity would not harm C storage for subtropical, broad-leaved secondary forest management.

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Application of AFLP fingerprint analysis for studying the biodiversity of Streptococcus thermophilus

Cited by 40 publications

References 27 publications

Quantitative Analysis of Histidine Decarboxylase Gene (hdcA) Transcription and Histamine Production by Streptococcus thermophilus PRI60 under Conditions Relevant to Cheese Making

Quantitative Analysis of Histidine Decarboxylase Gene (hdcA) Transcription and Histamine Production by Streptococcus thermophilus PRI60 under Conditions Relevant to Cheese Making

Identification of a Tyrosine Decarboxylase Gene ( tdcA ) in Streptococcus thermophilus 1TT45 and Analysis of Its Expression and Tyramine Production in Milk

Carbon distribution and its correlation with floristic diversity in subtropical broad-leaved forests during natural succession

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