Zhuang Guo

A phylo-functional core of gut microbiota in healthy young Chinese cohorts across lifestyles, geography and ethnicities

Structural profiling of healthy human gut microbiota across heterogeneous populations is necessary for benchmarking and characterizing the potential ecosystem services provided by particular gut symbionts for maintaining the health of their hosts. Here we performed a large structural survey of fecal microbiota in 314 healthy young adults, covering 20 rural and urban cohorts from 7 ethnic groups living in 9 provinces throughout China. Canonical analysis of unweighted UniFrac principal coordinates clustered the subjects mainly by their ethnicities/geography and less so by lifestyles. Nine predominant genera, all of which are known to contain short-chain fatty acid producers, co-occurred in all individuals and collectively represented nearly half of the total sequences. Interestingly, species-level compositional profiles within these nine genera still discriminated the subjects according to their ethnicities/geography and lifestyles. Therefore, a phylogenetically diverse core of gut microbiota at the genus level may be commonly shared by distinctive healthy populations as functionally indispensable ecosystem service providers for the hosts.

Intestinal Microbiota Distinguish Gout Patients from Healthy Humans

Current blood-based approach for gout diagnosis can be of low sensitivity and hysteretic. Here via a 68-member cohort of 33 healthy and 35 diseased individuals, we reported that the intestinal microbiota of gout patients are highly distinct from healthy individuals in both organismal and functional structures. In gout, Bacteroides caccae and Bacteroides xylanisolvens are enriched yet Faecalibacterium prausnitzii and Bifidobacterium pseudocatenulatum depleted. The established reference microbial gene catalogue for gout revealed disorder in purine degradation and butyric acid biosynthesis in gout patients. In an additional 15-member validation-group, a diagnosis model via 17 gout-associated bacteria reached 88.9% accuracy, higher than the blood-uric-acid based approach. Intestinal microbiota of gout are more similar to those of type-2 diabetes than to liver cirrhosis, whereas depletion of Faecalibacterium prausnitzii and reduced butyrate biosynthesis are shared in each of the metabolic syndromes. Thus the Microbial Index of Gout was proposed as a novel, sensitive and non-invasive strategy for diagnosing gout via fecal microbiota.

Effect of oral consumption of probiotic Lactobacillus planatarum P-8 on fecal microbiota, SIgA, SCFAs, and TBAs of adults of different ages

OBJECTIVE Probiotics may improve intestinal health by modulating intestinal microbiota. However, the age-related variation in response to probiotic consumption is understudied. The aim of this study was to determine the effect of oral consumption of Lactobacillus plantarum P-8 (Lp-8) on human intestinal microflora, secretary immunoglobulin A (SIgA), total bile acids (TBAs), and short-chain fatty acids (SCFAs) of different aged adults. METHODS Thirty-three recruited individuals, including young (mean age 26 y), middle-aged (mean age 51 y), and elderly (mean age 76 y) volunteers, were given a single daily oral dose of Lp-8 (6 × 10(10) colony forming units) for 4 wk. Fecal samples were collected before starting, during, and after stopping Lp-8 intake. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis, quantitative PCR, high-performance liquid chromatography, and enzyme-linked immunosorbent assay were used to detect for fecal microflora, SIgA, TBAs, and SCFAs. RESULTS Results showed an increase in Bifidobacterium (P < 0.05) and other beneficial bacteria, whereas Desulfovibrio (P < 0.05) and other opportunistic pathogens decreased after taking Lp-8 for 4 wk. Lp-8 consumption also affected fecal levels of SIgA, TBAs, and SCFAs. CONCLUSIONS Lp-8 administration could improve human gastrointestinal health. However, some of these effects were transient and gradually disappeared once the intervention was discontinued. Moreover, the extent of these desirable effects was age-related.

High-throughput sequencing for the detection of the bacterial and fungal diversity in Mongolian naturally fermented cow’s milk in Russia

BackgroundTraditional fermented dairy products are major components of the typical Mongolian diet since ancient times. However, almost all the previous studies on the microbial composition of traditional Mongolian fermented dairy products analyzed food samples from the Chinese Mongolian region and Mongolia but not the Russian Mongolian region. In this study, the bacterial and fungal community diversity of nineteen naturally fermented cow’s milk (NFCM) samples from local Mongolian families residing in Kalmykia and Chita of Russia was investigated with pyrosequencing.ResultsFirmicutes and Ascomycota were the predominant phyla respectively for bacteria and fungi. The abundance of the bacterial phylum Acidobacteria was considerably different between the samples from the two regions. At genus level, Lactobacillus and Pichia were the predominating bacterial and fungal genera, respectively, while six bacterial genera significantly differed between the Kalmykia (enrichment of Aeromonas, Bacillus, Clostridium, Streptococcus, Vogesella) and Chita (enrichment of Lactococcus) samples. The results of principal coordinate analysis (PCoA) based on the bacterial or fungal composition of the Kalmykia and Chita samples revealed a different microbiota structure between the samples collected in these two locations. The redundancy analysis (RDA) identified 60 bacterial and 21 fungal OTUs as the key variables responsible for such microbiota structural difference.ConclusionsOur results suggest that structural differences existed in the microbiota of NFCM between Kalmykia and Chita. The difference in geographic environment may be an important factor influencing the microbial diversity of NFCM made by the Mongolians in Russia.

454 pyrosequencing reveals changes in the faecal microbiota of adults consuming Lactobacillus casei Zhang

Probiotics are believed to help to maintain a healthy balance of the human gut microbiota. Lactobacillus casei Zhang (LcZ) is a novel potential probiotic isolated from the naturally fermented food koumiss. To better understand the impact of this potential probiotic on human intestinal microbiota, 24 subjects were randomly recruited for a longitudinal study: the subjects were required to consume LcZ for 28 days, and faecal samples were collected prior to, during and after the LcZ consumption phase. Alterations in the gut microbiota were monitored using 454 pyrosequencing and quantitative polymerase chain reaction(q-PCR) technologies. We found that the consumption of LcZ significantly altered the composition of intestinal microbiota (P < 0.001) and the gut microbiota diversity. Further analysis at the genus level revealed a positive correlation between LcZ and Prevotella, Lactobacillus, Faecalibacterium, Propionibacterium, Bifidobacterium and an unidentified genus from Bacteroidaceae and Lachnospiraceae and a negative correlation between LcZ administration and the presence of Clostridium, Phascolarctobacterium, Serratia, Enterococcus, Shigella and Shewanella. Furthermore, these changes were confirmed by q-PCR data.

Characterization of fecal microbiota across seven Chinese ethnic groups by quantitative polymerase chain reaction.

The human gut microbiota consists of complex microbial communities, which possibly play crucial roles in physiological functioning and health maintenance. China has evolved into a multicultural society consisting of the major ethnic group, Han, and 55 official ethnic minority groups. Nowadays, these minority groups inhabit in different Chinese provinces and some of them still keep their unique culture and lifestyle. Currently, only limited data are available on the gut microbiota of these Chinese ethnic groups. In this study, 10 major fecal bacterial groups of 314 healthy individuals from 7 Chinese ethnic origins were enumerated by quantitative polymerase chain reaction. Our data confirmed that the selected bacterial groups were common to all 7 surveyed ethnicities, but the amount of the individual bacterial groups varied to different degree. By principal component and canonical variate analyses of the 314 individuals or the 91 Han subjects, no distinct group clustering pattern was observed. Nevertheless, weak differences were noted between the Han and Zhuang from other ethnic minority groups, and between the Heilongjiang Hans from those of the other provinces. Thus, our results suggest that the ethnic origin may contribute to shaping the human gut microbiota.

Assessment of the bacterial and fungal diversity in home-made yoghurts of Xinjiang, China by pyrosequencing.

BACKGROUND The aim of this study was to gain a deeper knowledge of the bacterial and fungal community diversity in local home-made yoghurts from Zhaosu and Tekesi counties, Xinjiang, China, where a relatively high proportion of the ethnic minority population resides. RESULTS The bacterial and fungal community diversity in 22 home-made yoghurt samples was analyzed by pyrosequencing. This approach revealed the presence of six bacterial and two fungal phyla, comprising 69 bacterial and 20 fungal genera respectively, among all samples. Firmicutes and Ascomycota were the dominant phyla and Lactobacillus and Saccharomyces the predominant genera of bacteria and fungi respectively. Based on redundancy analysis, the bacterial diversity in samples from the two counties differed mainly because of eight responsive operational taxonomic units of Lactobacillus. However, no obvious difference existed in the fungal population of samples from the two counties. CONCLUSION The results indicated that the microbial community of home-made yoghurts varied with their geographical origin and manufacturing process. The study showed that pyrosequencing could provide a better understanding of microbiological diversity as well as useful information for future studies on the selection of starter cultures for yoghurts.

High-throughput sequencing reveals microbial community diversity of Tibetan naturally fermented yak milk

Naturally fermented yak milk (NFYM) is a traditional Tibetan fermented product that contains a rich microbial community. This study used high-throughput pyrosequencing to investigate the bacterial and fungal community diversity of 16 NFYM samples from the villages Geda and Ningzhong in Tibet. Pyrosequencing produced a total of 112,173 high quality bacterial 16S rRNA gene sequences and 90,980 fungal high quality reads from the NFYM. Sequence analysis grouped the high quality gene sequences into eleven bacterial and five fungal phyla, of which Firmicutes and Ascomycota dominated. At the genus level, Lactobacillus and Saccharomyces were the dominating bacteria and fungi, respectively. Principal coordinate analysis (PCoA) based on weighted and unweighted UniFrac values revealed no significant differences in the structure of bacterial and fungal microbiota. However, multivariate analysis of variance (MANOVA) based on unweighted UniFrac distances showed significant differences (P < 0.05) between the bacterial and fungal populations of the two NFYM samples from different villages. After the redundancy analysis (RDA), 49 key responding operational taxonomic units (OTUs) could be identified. Among them, 7 OTUs (Acinetobacter, unidentified Bacteroidetes, Lactobacillus, unidentified Proteobacteria, Streptococcus, Pantoea, and unidentified Firmicutes) were enriched in the Geda village samples, while 42 OTUs (mainly Massilia, Propionibacterium, Lactococcus, Leuconostoc, and Enterococcus) were enriched in the Ningzhong village samples. The present work provided insights into the microbiome of Tibetan NFYM and showed that the microbiota composition may be stratified by their geographic regions.

A pilot study on the effect of Lactobacillus casei Zhang on intestinal microbiota parameters in Chinese subjects of different age

Ageing of the population is an imminent global problem. Lactobacillus casei Zhang (LcZ) was isolated from Inner Mongolian fermented milk, koumiss. LcZ possesses numerous probiotic properties in in vitro tests and in animal models. However, it has never been tested in any human trial. In the current study, the impact of oral consumption of LcZ on different age groups was tested. Chinese subjects, including 10 young, 7 middle-aged and 7 elderly volunteers (with mean age of 24.3, 47.6 and 64.7, respectively), were recruited. Each subject took 10.6 log10 cfu LcZ daily for a continuous period of 28 days. Several parameters, including the amounts of LcZ and four selected groups of bacteria, change of bacterial diversity, short chain fatty acids (SCFA) and total bile acids (TBA), were monitored in faecal samples collected from the subjects before starting, during and after stopping oral LcZ consumption. The consumption of LcZ exhibited beneficial effects to the subjects by modulating faecal microbiota in a temporal manner with a prolonged elevation of SCFA and reduction of TBA. The potentially harmful Pseudomonas and Acinetobacter genera were suppressed by the probiotic administration. Furthermore, a moderately divergent response was observed in the indigenous gut populations of Bifidobacterium and Bacteroides fragilis group in different age subjects. Taken together, the current study has provided proof on the positive effect of probiotic consumption and crucial insights into the design and application of probiotic-based products to users of different age segments.

The diversity of intestinal microbiota of Mongolians living in Inner Mongolia, China

The Mongolian nationality has developed their unique lifestyle and dietary habit for thousands of years. However, by now, little research has been focused on Mongolian gut microbiota and how it is related to different dietary habits. In this study, denaturing gradient gel electrophoresis (DGGE) and quantitative polymerase chain reaction (qPCR) methods were applied to reveal the diversity of predominant gut bacteria of 48 healthy Mongolians recruited from Hohhot city and the Xilin Gol pasturing area in Inner Mongolia. Compared to similar studies of other nationalities, results from the present study have confirmed that the composition of Mongolian gut microbiota is highly similar at the phylum level (Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria) but variable at the genus level. Especially, the numbers of Phascolarctobacterium, Lactobacillus and Bifidobacterium are rather high. DGGE profiles of Lactobacillus and Bifidobacterium revealed that Lactobacillus casei, Bifidobacterium longum and Bifidobacterium animalis subsp. lactis were predominant in the gut of the Mongolian subjects studied. On the contrary, Lactobacillus helveticus was detected in every pasturing area Mongolian, but not in any of the Hohhot city Mongolians. qPCR results revealed that the numbers of Lactobacillus and Bifidobacterium of Xilin Gol Mongolians were significantly higher (P<0.05) than that of Hohhot Mongolians, whereas the numbers of Enterobacterium were significantly lower (P<0.05). In addition, by partial least squares discriminate analysis and cluster analysis of data generated from DGGE and qPCR experiments, a striking difference in the composition of intestinal microbiota of Mongolians living in Hohhot city and the Xilin Gol pasturing area has been found. This study clearly shows that diet affects the microbiota composition of Mongolians living in different circumstances, i.e. urban versus rural.