Christensenella minuta interacts with multiple gut bacteria.

Introduction: Gut microbes form complex networks that significantly influence host health and disease treatment. Interventions with the probiotic bacteria on the gut microbiota have been demonstrated to improve host well-being. As a representative of next-generation probiotics, Christensenella minuta (C. minuta) plays a critical role in regulating energy balance and metabolic homeostasis in human bodies, showing potential in treating metabolic disorders and reducing inflammation. However, interactions of C. minuta with the members of the networked gut microbiota have rarely been explored. Methods: In this study, we investigated the impact of C. minuta on fecal microbiota via metagenomic sequencing, focusing on retrieving bacterial strains and coculture assays of C. minuta with associated microbial partners. Results: Our results showed that C. minuta intervention significantly reduced the diversity of fecal microorganisms, but specifically enhanced some groups of bacteria, such as Lactobacillaceae. C. minuta selectively enriched bacterial pathways that compensated for its metabolic defects on vitamin B1, B12, serine, and glutamate synthesis. Meanwhile, C. minuta cross-feeds Faecalibacterium prausnitzii and other bacteria via the production of arginine, branched-chain amino acids, fumaric acids and short-chain fatty acids (SCFAs), such as acetic. Both metagenomic data analysis and culture experiments revealed that C. minuta negatively correlated with Klebsiella pneumoniae and 14 other bacterial taxa, while positively correlated with F. prausnitzii. Our results advance our comprehension of C. minuta's in modulating the gut microbial network. Conclusions: C. minuta disrupts the composition of the fecal microbiota. This disturbance is manifested through cross-feeding, nutritional competition, and supplementation of its own metabolic deficiencies, resulting in the specific enrichment or inhibition of the growth of certain bacteria. This study will shed light on the application of C. minuta as a probiotic for effective interventions on gut microbiomes and improvement of host health.

Changes to gut amino acid transporters and microbiome associated with increased E/I ratio in Chd8+/- mouse model of ASD-like behavior.

Autism spectrum disorder (ASD), a group of neurodevelopmental disorders characterized by social communication deficits and stereotyped behaviors, may be associated with changes to the gut microbiota. However, how gut commensal bacteria modulate brain function in ASD remains unclear. Here, we used chromodomain helicase DNA-binding protein 8 (CHD8) haploinsufficient mice as a model of ASD to elucidate the pathways through which the host and gut microbiota interact with each other. We found that increased levels of amino acid transporters in the intestines of the mouse model of ASD contribute to the high level of serum glutamine and the increased excitation/inhibition (E/I) ratio in the brain. In addition, elevated α-defensin levels in the haploinsufficient mice resulted in dysregulation of the gut microbiota characterized by a reduced abundance of Bacteroides. Furthermore, supplementation with Bacteroides uniformis improved the ASD-like behaviors and restored the E/I ratio in the brain by decreasing intestinal amino acid transport and the serum glutamine levels. Our study demonstrates associations between changes in the gut microbiota and amino acid transporters, and ASD-like behavioral and electrophysiology phenotypes, in a mouse model.

Parabacteroides distasonis Alleviates Obesity and Metabolic Dysfunctions via Production of Succinate and Secondary Bile Acids.

We demonstrated the metabolic benefits of Parabacteroides distasonis (PD) on decreasing weight gain, hyperglycemia, and hepatic steatosis in ob/ob and high-fat diet (HFD)-fed mice. Treatment with live P. distasonis (LPD) dramatically altered the bile acid profile with elevated lithocholic acid (LCA) and ursodeoxycholic acid (UDCA) and increased the level of succinate in the gut. In vitro cultivation of PD demonstrated its capacity to transform bile acids and production of succinate. Succinate supplementation in the diet decreased hyperglycemia in ob/ob mice via the activation of intestinal gluconeogenesis (IGN). Gavage with a mixture of LCA and UDCA reduced hyperlipidemia by activating the FXR pathway and repairing gut barrier integrity. Co-treatment with succinate and LCA/UDCA mirrored the benefits of LPD. The binding target of succinate was identified as fructose-1,6-bisphosphatase, the rate-limiting enzyme in IGN. The succinate and secondary bile acids produced by P. distasonis played key roles in the modulation of host metabolism.

Wenxinia marina gen. nov., sp. nov., a novel member of the Roseobacter clade isolated from oilfield sediments of the South China Sea.

An aerobic and heterotrophic, Gram-negative bacterial isolate, strain HY34(T), was isolated from sediment of an oilfield in the South China Sea, China. The taxonomy of strain HY34(T) was studied by phenotypic and phylogenetic methods. Strain HY34(T) formed faint-pink colonies on marine agar 2216. Cells of strain HY34(T) were non-motile, ovoid or short rods. Strain HY34(T) was positive for catalase and oxidase, and nitrate was reduced to nitrite. The nearly complete 16S rRNA gene sequence of strain HY34(T) was obtained and sequence analysis showed that it, together with the genus Rubellimicrobium, formed a distinct clade close to some members of the Roseobacter clade in the family Rhodobacteraceae, and it showed highest sequence similarities to Oceanicola granulosus HTCC2516(T) (93.8 %), Silicibacter lacuscaerulensis ITI-1157(T) (93.3 %), Dinoroseobacter shibae DFL 12(T) (93.3 %) and Rubellimicrobium thermophilum C-lvk-R2A-2(T) (92.2 %). Bacteriochlorophyll a was not detected. The ubiquinone system was Q-10. The major polar lipids were phosphatidylglycerol, phosphatidylcholine and an unidentified glycolipid. The major fatty acids (>10 %) were C(18 : 1) omega 7c and C(16 : 0). The DNA G+C content of this strain was 69.4 mol%. A polyphasic analysis supported the conclusion that this strain represents a novel genus and species, which we designated Wenxinia marina gen. nov., sp. nov. The type strain of Wenxinia marina is HY34(T) (=CGMCC 1.6105(T) =JCM 14017(T)).

[Isolation and identification of a PAHs-degrading strain Gordonia sp. He4 and its dynamics during bioremediation of phenanthrene polluted soil].

A bacterial strain, He4, capable of degrading n-hexadecane and other polycyclic aromatic compounds was isolated from petroleum polluted soil. This strain was identified as Gordonia sp. He4 according to its morphology, physiological, biochemical properties and the analysis of its 16S rRNA gene sequence. Based on its 16S rRNA gene sequence, specific primers were designed and a competitor template was amplified by PCR. The dynamics of strain He4 in phenanthrene polluted soil was analyzed by colony forming unit (CFU) method and QC-PCR method. The results showed that partial of He4 become non-culturable and un-detectable by CFU method. But by using QC-PCR, the population density of strain He4 could be measured accurately.

[Function analysis of the effective strain Rhodococcus ruber Em1 in wastewater treatment system by quantitative competitive PCR].

A quantitative competitive PCR (QC-PCR) system was developed to quantify the number and analyze the function of the Rhodococcus ruber Em1 strain in a wastewater treatment system in Nanchong oil refinery plant. Strain Em1 was able to degrade various kinds of hydrocarbons and aromatic compounds with high efficiency and produce bioemulsifier, so it was introduced into the waste liquid petroleum-disposing system. The sediment samples were collected from the disposing system in the range of 5 months, and then the numbers of strain Eml and degrading efficiencies were studied. The results showed that the primers based on 16S rRNA gene sequence of strain Em1 were specific at species level. The PCR products amplified from sediment total DNA with the specific primers were cloned and sequenced, in which 62.2% were the fragments of 16S rRNA gene of strain Em1. Furthermore, the number of Em1 strain ranging from 3.4 x 10(5) - 4.3 x 10(8) CFU/g in the sediment samples were detected, which indicated that the strain Eml added into purposely did exist stably and reproduced well in the waste-deposing system during a long period. The high relativity, with relative coefficient R2 of 0.89, between Eml cell number and the amount of COD (Chemical Oxygen Demand) removal proved that the strain Em1 played an important role in this bio-augmentation treatment system.

Cyclobacterium lianum sp. nov., a marine bacterium isolated from sediment of an oilfield in the South China Sea, and emended description of the genus Cyclobacterium.

The marine bacterial strain HY9(T) was isolated from sediment from the South China Sea. Strain HY9(T) is aerobic, heterotrophic and rose-pigmented. The cells are non-motile and curved, i.e. ring-like or horseshoe-shaped. The 16S rRNA gene sequence of strain HY9(T) was determined and blast searches revealed that it possessed significant sequence similarities with respect to Cyclobacterium species (92.8-93.6 %). Phylogenetic analysis confirmed that strain HY9(T) was tightly clustered with members of the genus Cyclobacterium. The cellular morphology and chemotaxonomic and phenotypic properties of strain HY9(T) showed that it should be classified as a member of the genus Cyclobacterium. Significant evolutionary distances and a range of phenotypic features distinguished strain HY9(T) from previously described Cyclobacterium species. Hence, strain HY9(T) represents a novel species in the genus Cyclobacterium, for which the name Cyclobacterium lianum sp. nov. is proposed. The type strain is HY9(T) (=CGMCC 1.6102(T)=JCM 14011(T)). On the basis of this study and previously described properties of Cyclobacterium species, an emended description of the genus Cyclobacterium is proposed.

[Bacterial conversion of sulfur-and phosphorous-compounds and microbial diversity in sediments from a near-shore marine-cultural region].

The H2S-producing bacteria and the phosphorous-cycling bacteria in sediments from near-shore marine-cultural region were investigated. Results indicate that the bacterial H2S production in aerobic condition is the dominating process to produce H2S in the sediment of cultural pond. The total counts of H2S-producing bacteria utilizing cysteine and Na2S2O3 were 1.6 x 10(6) and 4.35 x 10(3) cells g(-1) respectively. The counts of sulfate-reducing bacteria in the sediments were very little, only 2.5 x 10(1) g(-1). Further results show that the bacterial counts of decomposing lecithin and secreting phosphatase were 2.17 x 10(5) and 1.21 x 10(6) g(-1) respectively, bacterial counts of dissolving Ca3PO4 were 6.96 x 10(3) g(-1). Traditional taxonomy and partial 16S rRNA gene sequencing on the H2S-producing and phosphate-cycling bacteria indicate that most isolates could be classified as members of the following Genera: Bacillus, Halobacillus, Microbacterium, etc.