scholarly journals The Tape Measure Protein Is Involved in the Heat Stability ofLactococcus lactisPhages

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Hany Geagea ◽  
Simon J. Labrie ◽  
Muriel Subirade ◽  
Sylvain Moineau
Keyword(s):  
Lactococcus Lactis ◽  
Control Strategies ◽  
Heat Stability ◽  
Genetic Determinant ◽  
Tape Measure Protein ◽  
Content Type ◽  
Milk Fermentation ◽  
Gene Coding ◽  
Fermented Dairy Products ◽  
Fermented Dairy

ABSTRACTVirulent lactococcal phages are still a major risk for milk fermentation processes as they may lead to slowdowns and low-quality fermented dairy products, particularly cheeses. Some of the phage control strategies used by the industry rely on heat treatments. Recently, a fewLactococcus lactisphages were found to be highly thermo-resistant. To identify the genetic determinant(s) responsible for the thermal resistance of lactococcal phages, we used the virulent phage CB14 (of theLactococcus lactis936 [nowSk1virus] phage group) to select for phage mutants with increased heat stability. By treating phage CB14 to successive low and high temperatures, we were able to select two CB14 derivatives with increased heat stability. Sequencing of their genome revealed the same nucleotide sequences as the wild-type phage CB14, except for a same-sized deletion (120 bp) in the gene coding for the tape measure protein (TMP) of each phage mutant, but at a different position. The TMP protein sequences of these mutant phages were compared with their homologues in other wild-typeL. lactisphages with a wide diversity in heat stability. Comparative analysis showed that the same nucleotide deletion appears to have also occurred in the gene coding for the TMP of highly thermo-resistant lactococcal phages P1532 and P680. We propose that the TMP is, in part, responsible for the heat stability of the highly predominant lactococcal phages of theSk1virusgroup.IMPORTANCEVirulent lactococcal phages still represent a major risk for milk fermentation as they may lead to slowdowns and low-quality fermented dairy products. Heat treatment is one of the most commonly used methods to control these virulent phages in cheese by-products. Recently, a fewLactococcus lactisphages, members of theSk1virusgroup, have emerged with high thermal stability. To our knowledge, the genetic determinant(s) responsible for this thermal resistance in lactococcal phages is unknown. A better understanding of the thermal stability of these emerging virulent lactococcal phages is needed to improve industrial control strategies. In this work, we report the identification of a phage structural protein that is involved in the heat stability of a virulentSk1virusphage. Identifying such a genetic determinant for heat stability is a first step in understanding the emergence of this group of thermostable phages.

scholarly journals The Plasmid Complement of Lactococcus lactis UC509.9 Encodes Multiple Bacteriophage Resistance Systems

2014 ◽  
Vol 80 (14) ◽  
pp. 4341-4349 ◽  
Author(s):  
Stuart Ainsworth ◽  
Jennifer Mahony ◽  
Douwe van Sinderen
Keyword(s):  
Lactococcus Lactis ◽  
Starter Cultures ◽  
Phenotypic Traits ◽  
Abortive Infection ◽  
Content Type ◽  
Bacteriophage Resistance ◽  
Escape Mutants ◽  
Fermented Dairy Products ◽  
Fermented Dairy ◽  
Dairy Starter

ABSTRACTLactococcus lactissubsp.cremorisstrains are used globally for the production of fermented dairy products, particularly hard cheeses. Believed to be of plant origin,L. lactisstrains that are used as starter cultures have undergone extensive adaptation to the dairy environment, partially through the acquisition of extrachromosomal DNA in the form of plasmids that specify technologically important phenotypic traits. Here, we present a detailed analysis of the eight plasmids ofL. lactisUC509.9, an Irish dairy starter strain. Key industrial phenotypes were mapped, and genes that are typically associated with lactococcal plasmids were identified. Four distinct, plasmid-borne bacteriophage resistance systems were identified, including two abortive infection systems, AbiB and AbiD1, thereby supporting the observed phage resistance ofL. lactisUC509.9. AbiB escape mutants were generated for phage sk1, which were found to carry mutations inorf6, which encodes the major capsid protein of this phage.

scholarly journals Draft Genome Sequences of Four Lactococcus lactis Strains Isolated from Diverse Niches, Including Dairy Products, Grass, and Green Peas

2019 ◽  
Vol 8 (35) ◽  
Author(s):  
Desirée Roman Naranjo ◽  
Michael Callanan ◽  
Olivia McAuliffe
Keyword(s):  
Lactococcus Lactis ◽  
Dairy Products ◽  
Draft Genome ◽  
Genome Sequences ◽  
Content Type ◽  
Fermented Dairy Products ◽  
Fermented Dairy ◽  
Green Peas

Lactococcus lactis has been used for millennia as a starter organism in the production of many fermented dairy products. This announcement includes the draft genome sequences of four strains of Lactococcus lactis, two of dairy origin and two from nondairy sources.

scholarly journals Draft Genome Sequences of 24 Lactococcus lactis Strains

2017 ◽  
Vol 5 (13) ◽  
Author(s):  
Lennart Backus ◽  
Michiel Wels ◽  
Jos Boekhorst ◽  
Annereinou R. Dijkstra ◽  
Marke Beerthuyzen ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacterium ◽  
Lactococcus Lactis ◽  
Dairy Products ◽  
Draft Genome ◽  
Genome Sequences ◽  
Geographic Locations ◽  
Content Type ◽  
Fermented Dairy Products ◽  
Fermented Dairy

ABSTRACT The lactic acid bacterium Lactococcus lactis is widely used for the production of fermented dairy products. Here, we present the draft genome sequences of 24 L. lactis strains isolated from different environments and geographic locations.

Persistence of Escherichia coli O157:H7 in Dairy Fermentation Systems

1998 ◽  
Vol 61 (12) ◽  
pp. 1602-1608 ◽  
Author(s):  
SEAN S. DINEEN ◽  
KAZUE TAKEUCHI ◽  
JANE E. SOUDAH ◽  
KATHRYN J. BOOR
Keyword(s):  
Escherichia Coli ◽  
Lactococcus Lactis ◽  
Dairy Products ◽  
Starter Cultures ◽  
Escherichia Coli O157 ◽  
Potential Health ◽  
E Coli ◽  
Lactococcus Lactis Subsp ◽  
Fermented Dairy Products ◽  
Fermented Dairy

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 103 CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels >102 CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 105 CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

scholarly journals Involvement of the Major Capsid Protein and Two Early-Expressed Phage Genes in the Activity of the Lactococcal Abortive Infection Mechanism AbiT

2012 ◽  
Vol 78 (19) ◽  
pp. 6890-6899 ◽  
Author(s):  
Simon J. Labrie ◽  
Denise M. Tremblay ◽  
Maxim Moisan ◽  
Manuela Villion ◽  
Alfonso H. Magadán ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Major Capsid Protein ◽  
Control Strategies ◽  
Fermented Milk ◽  
Genomic Region ◽  
Comparative Genomic ◽  
Abortive Infection ◽  
Content Type ◽  
Milk Fermentation ◽  
Phage Morphogenesis

ABSTRACTThe dairy industry uses the mesophilic, Gram-positive, lactic acid bacterium (LAB)Lactococcus lactisto produce an array of fermented milk products. Milk fermentation processes are susceptible to contamination by virulent phages, but a plethora of phage control strategies are available. One of the most efficient is to use LAB strains carrying phage resistance systems such as abortive infection (Abi) mechanisms. Yet, the mode of action of most Abi systems remains poorly documented. Here, we shed further light on the antiviral activity of the lactococcal AbiT system. Twenty-eight AbiT-resistant phage mutants derived from the wild-type AbiT-sensitive lactococcal phages p2, bIL170, and P008 were isolated and characterized. Comparative genomic analyses identified three different genes that were mutated in these virulent AbiT-insensitive phage derivatives:e14(bIL170 [e14bIL170]),orf41(P008 [orf41P008]), andorf6(p2 [orf6p2] and P008 [orf6P008]). The genese14bIL170andorf41P008are part of the early-expressed genomic region, but bioinformatic analyses did not identify their putative function.orf6is found in the phage morphogenesis module. Antibodies were raised against purified recombinant ORF6, and immunoelectron microscopy revealed that it is the major capsid protein (MCP). Coexpression inL. lactisof ORF6p2and ORF5p2, a protease, led to the formation of procapsids. To our knowledge, AbiT is the first Abi system involving distinct phage genes.

scholarly journals Matrix Effects on the Delivery Efficacy of Bifidobacterium animalis subsp. lactis BB-12 on Fecal Microbiota, Gut Transit Time, and Short-Chain Fatty Acids in Healthy Young Adults

mSphere ◽  
2021 ◽  
Author(s):  
Zhaoyong Ba ◽  
Yujin Lee ◽  
Huicui Meng ◽  
Penny M. Kris-Etherton ◽  
Connie J. Rogers ◽  
...  
Keyword(s):  
Dairy Products ◽  
Matrix Effects ◽  
Probiotic Strain ◽  
Short Chain Fatty Acids ◽  
Fecal Microbiota ◽  
Gut Health ◽  
Content Type ◽  
Bifidobacterium Animalis ◽  
Fermented Dairy Products ◽  
Fermented Dairy

Bifidobacterium animalis subsp. lactis BB-12 is a probiotic strain that has been used worldwide since 1985. It has commonly been delivered in fermented dairy products for perceived benefits associated with gut health and enhanced immune function.

scholarly journals Complete Genome Sequence of Lactococcus lactis subsp. lactis KF147, a Plant-Associated Lactic Acid Bacterium

2010 ◽  
Vol 192 (10) ◽  
pp. 2649-2650 ◽  
Author(s):  
Roland J. Siezen ◽  
Jumamurat Bayjanov ◽  
Bernadet Renckens ◽  
Michiel Wels ◽  
Sacha A. F. T. van Hijum ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacterium ◽  
Lactococcus Lactis ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Circular Chromosome ◽  
Plant Environment ◽  
Fermented Dairy Products ◽  
Fermented Dairy

ABSTRACT Lactococcus lactis is a lactic acid bacterium used in the production of many fermented dairy products. We report the complete genome sequence of L. lactis subsp. lactis KF147, a nondairy strain isolated from mung bean sprouts. The circular chromosome of 2,598,144 bp, the largest among the sequenced lactococcal strains, encodes many properties related to adaptation to the plant environment.

scholarly journals Metagenomic Analysis of Dairy Bacteriophages: Extraction Method and Pilot Study on Whey Samples Derived from Using Undefined and Defined Mesophilic Starter Cultures

2017 ◽  
Vol 83 (19) ◽  
Author(s):  
Musemma K. Muhammed ◽  
Witold Kot ◽  
Horst Neve ◽  
Jennifer Mahony ◽  
Josué L. Castro-Mejía ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Extraction Method ◽  
Control Strategies ◽  
Standard Procedure ◽  
Starter Cultures ◽  
Surveillance Systems ◽  
Content Type ◽  
Depth Of Knowledge ◽  
Cost Efficient ◽  
Abundance And Diversity

ABSTRACT Despite being potentially highly useful for characterizing the biodiversity of phages, metagenomic studies are currently not available for dairy bacteriophages, partly due to the lack of a standard procedure for phage extraction. We optimized an extraction method that allows the removal of the bulk protein from whey and milk samples with losses of less than 50% of spiked phages. The protocol was applied to extract phages from whey in order to test the notion that members of Lactococcus lactis 936 (now Sk1virus), P335, c2 (now C2virus) and Leuconostoc phage groups are the most frequently encountered in the dairy environment. The relative abundance and diversity of phages in eight and four whey mixtures from dairies using undefined mesophilic mixed-strain cultures containing Lactococcus lactis subsp. lactis biovar diacetylactis and Leuconostoc species (i.e., DL starter cultures) and defined cultures, respectively, were assessed. Results obtained from transmission electron microscopy and high-throughput sequence analyses revealed the dominance of Lc. lactis 936 phages (order Caudovirales, family Siphoviridae) in dairies using undefined DL starter cultures and Lc. lactis c2 phages (order Caudovirales, family Siphoviridae) in dairies using defined cultures. The 936 and Leuconostoc phages demonstrated limited diversity. Possible coinduction of temperate P335 prophages and satellite phages in one of the whey mixtures was also observed. IMPORTANCE The method optimized in this study could provide an important basis for understanding the dynamics of the phage community (abundance, development, diversity, evolution, etc.) in dairies with different sizes, locations, and production strategies. It may also enable the discovery of previously unknown phages, which is crucial for the development of rapid molecular biology-based methods for phage burden surveillance systems. The dominance of only a few phage groups in the dairy environment signifies the depth of knowledge gained over the past decades, which served as the basis for designing current phage control strategies. The presence of a correlation between phages and the type of starter cultures being used in dairies might help to improve the selection and/or design of suitable, custom, and cost-efficient phage control strategies.

scholarly journals A Nonlive Preparation of Chromobacterium sp. Panama (Csp_P) Is a Highly Effective Larval Mosquito Biopesticide

2020 ◽  
Vol 86 (11) ◽  
Author(s):  
Eric P. Caragata ◽  
Luisa M. Otero ◽  
Jenny S. Carlson ◽  
Nahid Borhani Dizaji ◽  
George Dimopoulos
Keyword(s):  
Control Strategies ◽  
Heat Stability ◽  
High Heat ◽  
Field Trials ◽  
Mosquito Larvae ◽  
High Efficacy ◽  
Content Type ◽  
Target Disease ◽  
Spectrum Activity ◽  
Promising Source

ABSTRACT Given the continued high prevalence of mosquito-transmitted diseases, there is a clear need to develop novel disease and vector control strategies. Biopesticides of microbial origin represent a promising source of new approaches to target disease-transmitting mosquito populations. Here, we describe the development and characterization of a novel mosquito biopesticide, derived from an air-dried, nonlive preparation of the bacterium Chromobacterium sp. Panama (family: Neisseriaceae). This preparation rapidly and effectively kills the larvae of prominent mosquito vectors, including the dengue and Zika vector Aedes aegypti and the human malaria vector Anopheles gambiae. During semi-field trials in Puerto Rico, we observed high efficacy of the biopesticide against field-derived A. aegypti populations, and against A. aegypti and Culex species larvae in natural breeding water, indicating the suitability of the biopesticide for use under more natural conditions. In addition to high efficacy, the nonlive Csp_P biopesticide has a low effective dose, a long shelf life, and high heat stability and can be incorporated into attractive larval baits, all of which are desirable characteristics for a biopesticide. IMPORTANCE We have developed a novel preparation to kill mosquitoes from an abundant soil bacterium, Chromobacterium sp. Panama. This preparation is an air-dried powder containing no live bacteria, and it can be incorporated into an attractive bait and fed directly to mosquito larvae. We demonstrate that the preparation has broad spectrum activity against the larval form of the mosquitoes responsible for the transmission of malaria and the dengue, chikungunya, yellow fever, West Nile, and Zika viruses, as well as mosquito larvae that are already resistant to commonly used mosquitocidal chemicals. Our preparation possesses many favorable traits: it kills at a low dosage, and it does not lose activity when exposed to high temperatures, all of which suggest that this preparation could eventually become an effective new tool for controlling mosquitoes and the diseases they spread.

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