Difference between revisions of "Lactococcus lactis"

From MicrobeWiki, the student-edited microbiology resource
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==Cell structure and metabolism==
 
==Cell structure and metabolism==
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.
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The main metabolic pathway of ''L. lactis'' is the production of lactic acid that is used in food production. ''L. lactis'' utilizes anaerobic glycolysis to break down small amount of fermented sugar to pyruvate, then convert pyruvate to lactic acid with the main enzyme ldh, lactate dehydrogenase. Lactate will cause protons to be pumped out creating the membrane potential necessary for energy production. With this mechanism, ''L. lactis'' does not contain the genome encoded for citric cycle and gluconeogenesis, but does have functioning genome for aerobic respiration.
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Formation of lactate is not the only one fermentative pathway of ''L. lactis'', so food industry has studied further on many other fermentative products. The amount of each produced mainly bases on its corresponding enzymes activities on pyruvate. The understanding of each of the fermentative pathways helps food industry to synthesize compounds that are desired by manipulating and controlling the bacteria.
  
 
==Ecology==
 
==Ecology==

Revision as of 10:40, 3 May 2007

A Microbial Biorealm page on the genus Lactococcus lactis

Classification

Higher order taxa

Bacteria, Firmicutes, Bacilli, Lactobacillales, Streptococcacaeae, Lactococcus

Species

NCBI: Taxonomy

Lactococcus lactis

Description and significance

Lactococcus lactis is a rod shaped, gram positive bacteria used widely for producing fermented dairy products like milk, cheese, and yogurt. It is believed that in nature, L. lactis stays dormant on plant surface awaiting to be ingested along with the plant into animal gastrointestinal tract, where it becomes active. It is classified as a lactic acid bacterium(LAB) which converts carbohydrates into lactic acid. It plays an significant role to the food industry, so studies have been done on the genome of Lactococcus lactis extensively to improve its application in dairy products. Not only it is important in dairy production, it has potential of use as oral vaccine and foreign protein production and metabolite.

Genome structure

The genome of L. lactis is a circular chromosome with 2,365,589 base pairs where 86% of the genome codes for protein, 1.4% for RNA, and 12.6% for noncoding region. The initiation genes for DNA replication in L. lactis includes dnaB, dnaD, and dnaI, and polC and dnaE for DNA polymerase III. There are around some 30 genes found in L. lactis for transcription along with only 3 sigma-factor, while the translation mechanism comprise of 119 genes.

Cell structure and metabolism

The main metabolic pathway of L. lactis is the production of lactic acid that is used in food production. L. lactis utilizes anaerobic glycolysis to break down small amount of fermented sugar to pyruvate, then convert pyruvate to lactic acid with the main enzyme ldh, lactate dehydrogenase. Lactate will cause protons to be pumped out creating the membrane potential necessary for energy production. With this mechanism, L. lactis does not contain the genome encoded for citric cycle and gluconeogenesis, but does have functioning genome for aerobic respiration. Formation of lactate is not the only one fermentative pathway of L. lactis, so food industry has studied further on many other fermentative products. The amount of each produced mainly bases on its corresponding enzymes activities on pyruvate. The understanding of each of the fermentative pathways helps food industry to synthesize compounds that are desired by manipulating and controlling the bacteria.

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Rachel Larsen and Kit Pogliano