A robust plate assay for detection of extracellular microbial protease activity in metagenomic screens and pure cultures

Morris, Laura; Evans, James B.; Marchesi, Julian R.

doi:10.1016/j.mimet.2012.08.006

Cited by 29 publications

(21 citation statements)

References 9 publications

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“…The PrtS proteinase phenotype was phenotypically determined on bacterial colonies grown on semi skimmed milk agar plate according to Morris et al (2012). For each strain, 5 l of a routinely grown culture were dropped on lactose-free skim milk plates and incubated at 37°C for 24h and 48h.…”

Section: Acidification Kinetics and Protease Activity Determinationmentioning

confidence: 99%

Genome comparison and physiological characterization of eight Streptococcus thermophilus strains isolated from Italian dairy products

Vendramin¹,

Treu

Campanaro

et al. 2017

Food Microbiology

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Eight Streptococcus thermophilus strains of dairy origin isolated in Italy were chosen to investigate autochthonous bacterial diversity in this important technological species. In the present study a comparative analysis of all the 17 S. thermophilus genomes publicly available was performed to identify the core and the variable genes, which vary among strains from 196 to 265. Additionally, correlation between the isolation site and the genetic distance was investigated at genomic level. Results highlight that the phylogenetic reconstruction differs from the geographical strain distribution. Moreover, strain M17PTZA496 has a genome of 2.15 Mbp, notably larger than that of the others, determined by lateral gene transfer (including phage-mediated incorporation) and duplication events. Important technological characters, such as growth kinetics, bacteriocin production, acidification kinetics and surface adhesion capability were studied in all the Italian strains. Results indicate a wide range of variability in adhesion properties that significantly clustered strains into four groups. Genomic differences among strains in relation to these characters were identified but a clear correlation between genotype and phenotype was not always found since most of the genomic modifications arise from single nucleotide polymorphisms. This research represents a step forward in the identification of strains-specific functions in Streptococcus thermophilus and it has also the potential to provide valuable information to predict strain specific behaviors in industrial processes.

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Section: Acidification Kinetics and Protease Activity Determinationmentioning

confidence: 99%

Genome comparison and physiological characterization of eight Streptococcus thermophilus strains isolated from Italian dairy products

Vendramin¹,

Treu

Campanaro

et al. 2017

Food Microbiology

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show abstract

“…Consequently, no endopeptidase activity was detected in the supernatant after cultivation of LAB in milk medium, but clear hydrolysis zones are shown on the skim milk agar plates. Furthermore, false positive results for peptidase activity on skim milk agar plates can arise from acid formation from lactose by glycoside hydrolases (Morris, Evans, & Marchesi, 2012). The acid produced can hydrolyse the casein resulting in clear hydrolysis zones on the agar plates.…”

Section: Overview Of Enzyme Activity and Comparison To Agar Diffusionmentioning

confidence: 99%

Quantification of the proteolytic and lipolytic activity of microorganisms isolated from raw milk

Baur

Krewinkel

Kranz

et al. 2015

International Dairy Journal

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“…Although short sequences are present in all strains, their coverage (< 20%) was considered insufficient for gene functionality. Finally, a phenotypic assay performed on plate (Morris et al, 2012 ) showed absence of proteinase activity in all strains (data not shown), thus excluding a PrtS involvement in the diverse acidification capabilities recorded between TH1436 and TH1477.…”

Section: Resultsmentioning

confidence: 86%

Comparative Transcriptomic Analysis of Streptococcus thermophilus TH1436 and TH1477 Showing Different Capability in the Use of Galactose

et al. 2018

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Streptococcus thermophilus is a species widely used in the dairy industry for its capability to rapidly ferment lactose and lower the pH. The capability to use galactose produced from lactose hydrolysis is strain dependent and most of commercial S. thermophilus strains are galactose-negative (Gal−), although galactose-positive (Gal+) would be more technologically advantageous because this feature could provide additional metabolic products and prevent galactose accumulation in foods. In this study, a next generation sequencing transcriptome approach was used to compare for the first time a Gal+ and a Gal− strain to characterize their whole metabolism and shed light on their different properties, metabolic performance and gene regulation. Transcriptome analysis revealed that all genes of the gal operon were expressed very differently in Gal+ and in the Gal− strains. The expression of several genes involved in mixed acid fermentation, PTS sugars transporter and stress response were found enhanced in Gal+. Conversely, genes related to amino acids, proteins metabolism and CRISPR associated proteins were under-expressed. In addition, the strains showed a diverse series of predicted genes controlled by the transcriptional factor catabolite control protein A (CcpA). Overall, transcriptomic analysis suggests that the Gal+ strain underwent a metabolic remodeling to cope with the changed environmental conditions.

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A robust plate assay for detection of extracellular microbial protease activity in metagenomic screens and pure cultures

Cited by 29 publications

References 9 publications

Genome comparison and physiological characterization of eight Streptococcus thermophilus strains isolated from Italian dairy products

Genome comparison and physiological characterization of eight Streptococcus thermophilus strains isolated from Italian dairy products

Quantification of the proteolytic and lipolytic activity of microorganisms isolated from raw milk

Comparative Transcriptomic Analysis of Streptococcus thermophilus TH1436 and TH1477 Showing Different Capability in the Use of Galactose

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