Identification of key micro-organisms involved in Douchi fermentation by statistical analysis and their use in an experimental fermentation

AIMS

To screen and identify safe micro-organisms used during Douchi fermentation, and verify the feasibility of producing high-quality Douchi using these identified micro-organisms.

METHODS AND RESULTS

PCR-denaturing gradient gel electrophoresis (DGGE) and automatic amino-acid analyser were used to investigate the microbial diversity and free amino acids (FAAs) content of 10 commercial Douchi samples. The correlations between microbial communities and FAAs were analysed by statistical analysis. Ten strains with significant positive correlation were identified. Then an experiment on Douchi fermentation by identified strains was carried out, and the nutritional composition in Douchi was analysed. Results showed that FAAs and relative content of isoflavone aglycones in verification Douchi samples were generally higher than those in commercial Douchi samples.

CONCLUSIONS

Our study indicated that fungi, yeasts, Bacillus and lactic acid bacteria were the key players in Douchi fermentation, and with identified probiotic micro-organisms participating in fermentation, a higher quality Douchi product was produced.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report to analyse and confirm the key micro-organisms during Douchi fermentation by statistical analysis. This work proves fermentation micro-organisms to be the key influencing factor of Douchi quality, and demonstrates the feasibility of fermenting Douchi using identified starter micro-organisms.

Binding Patterns of Rotavirus Genotypes P[4], P[6], and P[8] in China with Histo-Blood Group Antigens

Rotaviruses (RVs) are an important cause of severe gastroenteritis in children. It has been found that RV may recognize the histo-blood group antigens (HBGAs) as ligands or receptors and bind HBGAs in a type-dependent manner. In this study, we investigated the binding specificity of VP8* proteins from human rotaviruses (RV) that are prevalent in China including genotypes P[4], P[6], and P[8]. Through the saliva- and oligosaccharide-based binding assays, we found that the VP8* proteins of P[4] and P[8] RV showed similar reactivity with the Le^b and H type 1 antigens, while P[6] RV weakly bound the Le^b antigen. These findings may facilitate further research into RV host specificity and vaccine development.

[Discovery of human bocavirus 4 in children with acute gastroenteritis in Lanzhou, China]

We studied the epidemiological characteristics of human bocavirus 4 (HBoV4) in children with a- cute gastroenteritis in Lanzhou (China). A total of 331 stool specimens were collected from children aged < 5 years with acute diarrhea at the First Hospital of Lanzhou University between July 2012 and June 2013. Specimens of HBoV were identified by nested polymerase chain reaction assays. Compared with related sequences in GenBank, the HBoV-positive strain isolated in the present study was,quite surprisingly, a rare genotype named HBoV4. This strain was a typical HBoV4,with high levels of nucleotide and amino acid homology to the Thailand strain, JQ267789 (98.9% and 98.7%, respectively), and the USA strain, GQ506568 (97.6% and 97.4%, respectively). This is the first report of HBoV4 as the causative agent for acute gastroenteritis in pediatric patients in China. This strain is one of two genotypes of HBoV that are currently circulating.

The production of monoclonal antibody to androstenedione and the effect of passive immunization on Xinjiang fine-wool sheep with it

Five hybridomas stably secreting monoclonal antibodies (McAbs) to androstenedione were prepared by using artificially synthesized androstenedion-11 alpha-succinyl conjugate with bovine serum albumin (BSA) as antigen. These McAbs showed slightly high cross-reactivity with testosterone (8.1-12.3%) and estrone (0.8-2.5%) and high affinities ranging from 2.0 x 10(7) to 2.8 x 10(8) L/M. They were all of the IgG1 subclass. Xinjiang finewool ewes which were passively immunized with McAbs had higher circulating levels of progesterone (P) and luteinizing hormone (LH) than those of control ewes in two oestrous cycles and these changes led to increased ovulation rate and twin lambs born in young ewes.