RT-qPCR analysis of dexB and galE gene expression of Streptococcus alactolyticus in Astragalus membranaceus fermentation

• Published in: Applied microbiology and biotechnology Vol. 97; no. 13; pp. 6009 - 6018
• Main Authors: Hao, Gui J., Zhang, Kai, Zhang, Jing Y., Wang, Xu R., Qin, Zhe, Wang, Xue Z., Wang, Lei, Meng, Jia R., Yang, Zhi Q., Li, Jian X.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-07-2013; Springer; Springer Nature B.V
• Subjects: Agricultural production; Analysis; Animals; Applied Microbial and Cell Physiology; Astragalus; Astragalus membranaceus - chemistry; Bacteria; Bacterial genetics; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Cecum; Cecum - microbiology; Chickens; Chickens - microbiology; Cloning; Cloning, Molecular; Dextrose; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Fermentation; Flowers & plants; Gene amplification; Gene expression; Gene Expression Profiling; Genomes; Glucose; Glucosidases - biosynthesis; Glucosidases - chemistry; Glucosidases - genetics; Gram-positive bacteria; Life Sciences; Microbial Genetics and Genomics; Microbiology; Microbiota; Models, Molecular; Molecular Conformation; Molecular Sequence Data; Pharmaceutical sciences; Phylogeny; Polysaccharides; Polysaccharides - metabolism; Protein Conformation; Rats; Real-Time Polymerase Chain Reaction; Saccharides; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Streptococcus - enzymology; Streptococcus - genetics; Streptococcus - isolation & purification; Streptococcus - metabolism; Studies; UDPglucose 4-Epimerase - biosynthesis; UDPglucose 4-Epimerase - chemistry; UDPglucose 4-Epimerase - genetics; Veterinary medicine; Glucan-1,6-α-glucosidase; Genome walking; RT-qPCR; UDP-glucose 4-epimerase
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-013-4873-2

Streptococcus alactolyticus
strain FGM, isolated from chicken cecum, was used to increase the extract yield of polysaccharides during
Astragalus membranaceus
fermentation. It was previously demonstrated that polysaccharides from fermented
A
.
membranaceus
by
S
.
alactolyticus
had some similar properties to those from
A
.
membranaceus
in terms of its ability to help heal hepatic fibrosis in rats and modulate immunopotentiation of broiler chicken. However, methods to increase the yield of the polysaccharides during fermentation of
A
.
membranaceus
are not well understood. In this paper, we investigated the involvement of uridine diphosphate (UDP)-glucose 4-epimerase (
galE
) and glucan-1,6-α-glucosidase (
dexB
) during
A
.
membranaceus
fermentation through real-time reverse transcription quantitative PCR. The
galE
and
dexB
genes of
S
.
alactolyticus
were cloned by homology-based cloning and the genome walking method for the first time, and the 3D structure of
dexB
was analyzed by Swiss-PdbViewer 4.0.1 software. The expression of both the
galE
and
dexB
genes in
A
.
membranaceus
fermentation was studied using the determined ideal reference gene
ldh
for transcript normalization. The results showed that these two genes were both highly induced and peaked after 12 h of fermentation. The expression level of
galE
was stepwise increased from 48 to 72 h, while
dexB
transcripts were markedly increased at 60 h and decreased by 72 h. These data suggested that
dexB
and
galE
of
S
.
alactolyticus
strain FGM were involved in the regulation of
A
.
membranaceus
fermentation and they might play some roles in the increase of polysaccharides.