Related Experiment Video
Updated: Jan 7, 2026
09:44
Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing
Published on: December 23, 2022
2.8K
Comprehensive Characterization of Five Lactococcus Strains: From Phenotypic Traits to Genomic Features
I D Antipenko1, N P Sorokina2, I V Kucherenko2
1Laboratory for Research on Molecular Mechanisms of Longevity, Department of Biology and Biotechnology, HSE University, Moscow, 101000 Russia.
Acta Naturae
|January 2, 2026
Summary
Understanding the genetic and phenotypic traits of lactic acid bacteria is crucial for dairy fermentation. This study reveals significant metabolic differences and phage resistance in Lactococcus strains, highlighting the need for integrated genomic and phenotypic analysis in starter culture selection.
Area of Science:
- Dairy Microbiology
- Bacteriology
- Genomics
Background:
- Dairy fermentation efficiency relies on lactic acid bacteria properties, including metabolic activity and phage resistance.
- Understanding the genotype-phenotype relationship in industrial strains is vital for optimizing dairy production.
Purpose of the Study:
- To comprehensively analyze genetic and phenotypic traits of five industrial Lactococcus strains.
- To investigate species-specific features of lactose metabolism in Lactococcus lactis and Lactococcus cremoris.
- To correlate the presence of prophages and specific genetic systems with phage resistance and metabolic activity.
Main Methods:
- Whole-genome sequencing of five industrial Lactococcus strains.
- Phenotypic profiling of bacterial metabolic activity and acidification.
- Comparative genomic analysis of 337 L. lactis and 147 L. cremoris genomes.
- Bacteriophage resistance testing and identification of phage defense systems.
Main Results:
- Significant metabolic activity differences were found among genetically similar L. lactis strains.
- Species-specific lactose metabolism features were identified, including the absence of the lacZ gene in L. cremoris.
- Prophages were detected in three strains, correlating with reduced acidification activity.
- Two L. lactis strains exhibited resistance to all tested bacteriophages, potentially due to the AbiB system.
Conclusions:
- Integrating genomic and phenotypic analyses is essential for selecting efficient and phage-resistant Lactococcus starter cultures.
- Genetic variations influence metabolic performance and phage susceptibility in industrial dairy strains.
- The AbiB system may confer broad-spectrum phage resistance in Lactococcus lactis.
Related Concept Videos
01:29Modern Molecular Taxonomy
541
Advancements in molecular biology have revolutionized the identification and characterization of bacteria, with multiple methods leveraging DNA sequencing for enhanced precision. As sequencing technologies improve and costs decline, these approaches are increasingly used in clinical, environmental, and evolutionary studies.Multilocus Sequence Typing (MLST) examines several housekeeping genes, essential chromosomal genes encoding cellular functions, to distinguish strains. Approximately...
541
01:28Methods of Classification and Identification
926
Bacterial identification relies on a diverse array of techniques to classify and understand microorganisms, each tailored to uncover specific characteristics. Traditional morphological approaches, while still valuable, are limited for closely related or structurally simple organisms. Modern methods integrate biochemical, serological, genetic, and advanced molecular tools to achieve greater accuracy.Morphological and Biochemical TechniquesMorphological characteristics, such as cell shape and...
926
02:09Operons
53.9K
Prokaryotes can control gene expression through operons—DNA sequences consisting of regulatory elements and clustered, functionally related protein-coding genes. Operons use a single promoter sequence to initiate transcription of a gene cluster (i.e., a group of structural genes) into a single mRNA molecule. The terminator sequence ends transcription. An operator sequence, located between the promoter and structural genes, prohibits the operon’s transcriptional activity if bound by...
53.9K
01:25Inducible Operons: lac Operon
1.3K
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA...
1.3K
01:24Bacterial Phylum Tenericutes
417
The phylum Tenericutes, which includes the single class Mollicutes, comprises bacteria that lack cell walls. The term "Mollicutes" derives from the Latin word mollis, meaning "soft." These organisms are among the smallest known and are commonly referred to as mycoplasmas due to the prominence of the genus Mycoplasma, which includes well-known human pathogens. Despite their inability to stain gram-positively (a result of their lack of cell walls), mycoplasmas are phylogenetically related to the...
417
01:27Bacterial Phylum Firmicutes
867
Firmicutes is a diverse phylum of Gram-positive bacteria characterized by a low GC content in their genomes. This phylum includes organisms with monoderm or diderm cell envelopes, highlighting a complex evolutionary history. Firmicutes comprises several major orders, including Lactobacillales, Clostridiales, and Bacillales, which exhibit remarkable diversity in their morphology, metabolism, and ecological roles.The order Lactobacillales includes lactic acid bacteria, which are fermentative...
867