Project description:Purpose: High γ-aminobutyric acid (GABA)-producing Levilactobacillus brevis strain NPS-QW 145 along with Streptococcus thermophilus (one of the two starter bacteria used to make yogurt for its proteolytic activity) to enhance GABA production in milk. But a mechanistic understanding on how Levilactobacillus brevis cooperated with S. thermophilus to stimulate GABA production has been lacking. Method: Metatranscriptomic analyses combined with peptidomics were carried out to unravel the casein and lactose utilization patterns during milk fermentation with the co-culture. Results: We found particular peptides hydrolyzed by S. thermophilus 1275 were transported and biodegraded with peptidase in Lb. brevis 145 to meet the growth needs of the latter. In addition, amino acid synthesis and metabolism in Lb. brevis 145 were also activated to further support its growth. Glucose, as a result of lactose hydrolysis by S. thermophilus 1275, but not available lactose in milk, was outcompeted by Lb. brevis 145 as a main carbon source for glycolysis to produce ATP.In the stationary phase, under the acidic condition due to accumulation of lactic acid produced by S. thermophilus 1275, genes expression involved in pyridoxal phosphate (coenzyme of glutamic acid decarboxylase) metabolism and glutamic acid decarboxylase (Gad) in Lb. brevis 145 were induced for GABA production.
Project description:The bacterium Corynebacterium glutamicum can produce ʟ-glutamic acid under certain growth conditions. ʟ-glutamic acid is used as a flavor enhancer, food supplement, or primary chemical raw material. It, therefore, plays an essential economic role with an annual production of over 2½ million tons. Due to metabolic development, the product range of C. glutamicum has been expanded to include all biogenic amino acids, vitamins, and more. Previously published metabolic models of C. glutamicum have been supplemented with new metabolic data and expanded with data from new systems biology programs to result in this consensus model.
Project description:RNA-seq was performed using 2 isogenic strains of E coli bearing either the wild type dnaN allele (strain VB001), or a dnaN allele with a glutamic acid-202 to lysine substitution (dnaN-E202K; strain VB019).
Project description:To compare transcriptional profiling of a gadE-, hdeA-, or hdeD- deficient strain to wild type in E. coli under minimum medium conditions. These genes are included in the GAD cluster genes, which are involved in the glutamic acid-dependent acid resistance (GAD) in E. coli. Goal was to determine the GadE, HdeA, or HdeD regulon in E. coli. Biological replicates: 2 replicates.
Project description:Fatty acid-amino acid conjugates (FACs) in the oral secretion (OS) of the Manduca sexta larvae are necessary and sufficient to elicit the herbivory-specific responses in Nicotiana attenuata, an annual wild tobacco species. We used SuperSAGE combined with 454 sequencing to quantify the early transcriptional changes elicited by the FAC N-linolenoyl-glutamic acid (18:3-Glu) in N. attenuata. The second fully expanded leaf of rosette stage plants were wounded by rolling a fabric pattern wheel three times on each side of the midvein and the wounds were immediately supplied with either 20 uL of 0.02% (v/v) Tween-20/water (solvent control) or 10 uL of synthetic N-linolenoyl-glutamic acid (18:3-Glu; 0.03 nmol/µL in 0.02% (v/v) Tween-20/water). Tissue was collected after 30 min of the treatments and frozen in liquid nitrogen. Total RNA was extracted by the phenol/chloroform-LiCl method and poly(A)+-RNA was purified from total RNA. Subsequent steps for the construction of the SuperSAGE libraries and 454 sequencing were performed as previously described using double NlaIII digestions (Molina et al., 2008, BMC Genomics, 9:553). Two SuperSAGE libraries were generated after wounding and FAC elicitation of Nicotiana attenuata leaves. Leaves were harvested after 30 min of the treatments, total RNA extracted, polyA+ mRNA isolated and used for cDNA synthesis and SuperSAGE analysis as described my Matsumura et al (2003).