Physiological responses to folate overproduction in Lactobacillus plantarum WCFS1.

Background: Using a functional genomics approach we addressed the impact of folate overproduction on metabolite formation and gene expression in Lactobacillus plantarum WCFS1. We focused specifically on the mechanism that reduces growth rates in folate-overproducing cells.

Results: Metabolite formation and gene expression were determined in a folate-overproducing- and wild-type strain.

Folate overproduction in Lactobacillus plantarum WCFS1 causes methotrexate resistance.

Folate overproduction can serve as a mode of resistance against the folate antagonist methotrexate in Lactobacillus plantarum WCFS1. When compared with a wild-type control strain, an engineered high folate-producing strain was found to be insensitive to methotrexate. The growth rate and the viable count of the folate-overproducing L.

High-Level folate production in fermented foods by the B12 producer Lactobacillus reuteri JCM1112.

We observed that Lactobacillus reuteri JCM1112 produces B(12) and folate. However, the folate/B(12) mass ratio found was far below that desired for human consumption ( approximately 170:1). We used metabolic engineering applying genetic and physiological approaches to improve this ratio and developed a generic and natural process that significantly increases folate production.

Characterization of the role of para-aminobenzoic acid biosynthesis in folate production by Lactococcus lactis.

The pab genes for para-aminobenzoic acid (pABA) biosynthesis in Lactococcus lactis were identified and characterized. In L. lactis NZ9000, only two of the three genes needed for pABA production were initially found.

In silico reconstruction of the metabolic pathways of Lactobacillus plantarum: comparing predictions of nutrient requirements with those from growth experiments.

On the basis of the annotated genome we reconstructed the metabolic pathways of the lactic acid bacterium Lactobacillus plantarum WCFS1. After automatic reconstruction by the Pathologic tool of Pathway Tools (http://bioinformatics.ai.

A nudix enzyme removes pyrophosphate from dihydroneopterin triphosphate in the folate synthesis pathway of bacteria and plants.

Removal of pyrophosphate from dihydroneopterin triphosphate (DHNTP) is the second step in the pterin branch of the folate synthesis pathway. There has been controversy over whether this reaction requires a specific pyrophosphohydrolase or is a metal ion-dependent chemical process. The genome of Lactococcus lactis has a multicistronic folate synthesis operon that includes an open reading frame (ylgG) specifying a putative Nudix hydrolase.

Transformation of folate-consuming Lactobacillus gasseri into a folate producer.

Five genes essential for folate biosynthesis in Lactococcus lactis were cloned on a broad-host-range lactococcal vector and were transferred to the folate auxotroph Lactobacillus gasseri. As a result L. gasseri changed from a folate consumer to a folate producer.