Impact of Environmental Microbes on the Composition of the Gut Microbiota of Adult BALB/c Mice.

To investigate the impact of microbes within the living environment on the gut microbiota of adults, we raised three groups of BALB/c mice from 3-4 weeks age in the same specific-pathogen-free animal room for 8 weeks. The control group lived in cages with sterilized bedding (pelletized cardboard), the probiotics group had three probiotics added to the sterilized bedding, and the intestinal microbes (IM) group had the intestinal microbes of a healthy goat added to the bedding. All other variables such as diet, age, genetic background, physiological status, original gut microbiota, and living room were controlled. Using high-throughput sequencing of the 16S rRNA gene, we observed that the control and probiotics groups had similar diversity and richness of gut microbiota. The two groups had significantly lower diversity than the IM group. We also observed that the IM group had a specific structure of gut microbial community compared with the control and probiotics groups. However, the dominate bacteria changed slightly upon exposure to intestinal microbes, and the abundance of the non-dominate species changed significantly. In addition, exposure to intestinal microbes inhibited DNFB-induced elevation of serum IgE levels. Our results provide new evidence in support of the microflora and hygiene hypotheses

Petroleum pollution changes microbial diversity and network complexity of soil profile in an oil refinery

IntroductionPetroleum pollution resulting from spills and leakages in oil refinery areas has been a significant environmental concern for decades. Despite this, the effects of petroleum pollutants on soil microbial communities and their potential for pollutant biodegradation still required further investigation.MethodsIn this study, we collected 75 soil samples from 0 to 5 m depths of 15 soil profiles in an abandoned refinery to analyze the effect of petroleum pollution on soil microbial diversity, community structure, and network co-occurrence patterns.ResultsOur results suggested soil microbial a-diversity decreased under high C10-C40 levels, coupled with significant changes in the community structure of soil profiles. However, soil microbial network complexity increased with petroleum pollution levels, suggesting more complex microbial potential interactions. A module specific for methane and methyl oxidation was also found under high C10-C40 levels of the soil profile, indicating stronger methanotrophic and methylotrophic metabolic activities at the heavily polluted soil profile.DiscussionThe increased network complexity observed may be due to more metabolic pathways and processes, as well as increased microbial interactions during these processes. These findings highlight the importance of considering both microbial diversity and network complexity in assessing the effects of petroleum pollution on soil ecosystems

SCP2 mediates the transport of lipid hydroperoxides to mitochondria in chondrocyte ferroptosis

Abstract Sterol carrier protein 2 (SCP2) is highly expressed in human osteoarthritis (OA) cartilage, accompanied by ferroptosis hallmarks, especially the accumulation of lipid hydroperoxides (LPO). However, the role of SCP2 in chondrocyte ferroptosis remains unexplored. Here, we identify that SCP2 transports cytoplasmic LPO to mitochondria in RSL3-induced chondrocyte ferroptosis, resulting in mitochondrial membrane damage and release of reactive oxygen species (ROS). The localization of SCP2 on mitochondria is associated with mitochondrial membrane potential, but independent of microtubules transport or voltage-dependent anion channel. Moreover, SCP2 promotes lysosomal LPO increase and lysosomal membrane damage through elevating ROS. However, SCP2 is not directly involved in the cell membrane rupture caused by RSL3. Inhibition of SCP2 markedly protects mitochondria and reduces LPO levels, attenuating chondrocyte ferroptosis in vitro and alleviating the progression of OA in rats. Our study demonstrates that SCP2 mediates the transport of cytoplasmic LPO to mitochondria and the spread of intracellular LPO, accelerating chondrocyte ferroptosis

Effects of exposure to different concentrations of microbes.

<p>(A) Total serum IgE levels; (B) Dermatitis scores of rostral back and ear in BALB/c mice treated with DNFB. Serum absorbance in each group was averaged and each bar represents mean ± SEM (n = 10; *<i>p <</i> 0.05, **<i>p <</i> 0.01, based on a two-tailed least significant difference test).</p

Principal coordinates analysis (PCoA) of unweighted and weighted UniFrac distances.

<p>These are for the fecal microbiota of the three experimental mice: control, probiotics, and intestinal microbes. Analysis was based on the Illumina bacterial 16S rRNA gene dataset (V4 region).</p

Comparison of bacterial richness and diversity among Control, Probiotics, and Microbes.

<p>Control mice were raised in cages with sterilized pelletized cardboard bedding, probiotics mice were raised in cages sterilized pelletized cardboard bedding added with probiotics, and intestinal microbes mice were raised in cages added with goat intestinal microbes. (A) Rarefaction curves showing unique operational taxonomic units (OTUs) (a box graph at the rarefied sequence number). (B) Chao1 estimators. (C) Phylogenetic diversity (PD). (D) Shannon index. (n = 8; * p < 0.05, ** p < 0.01, based on a two-tailed least significant difference test).</p

Comparison of OTU-levels in the gut microbiota between the control, probiotics, and intestinal microbes groups.

<p>(n = 8; *<i>p <</i> 0.05, **<i>p <</i> 0.01, based on a two-tailed least significant difference test).</p

Correlation between microbial richness/diversity and dermatitis severity indices and other variables.

<p>Correlation between microbial richness/diversity and dermatitis severity indices and other variables.</p

Heat map profiles and dendrograms of the most abundant OTUs in the gut microbiota for all samples.

<p>Experimental groups: control, probiotics, and intestinal microbes. Color represents relative abundance.</p

Distribution of Two HIV-1–Resistant Polymorphisms (SDF1-30A and CCR2-64I) in East Asian and World Populations and Its Implication in AIDS Epidemiology

Chemokine receptor CCR2 and stromal-derived factor (SDF-1) are involved in HIV infection and AIDS symptom onset. Recent cohort studies showed that point mutations in these two genes, CCR2-64I and SDF1-3′A, can delay AIDS onset ⩾16 years after seroconversions. The protective effect of CCR2-64I is dominant, whereas that of SDF1-3′A is recessive. SDF1-3′A homozygotes also showed possible protection against HIV-1 infection. In this study, we surveyed the frequency distributions of the two alleles at both loci in world populations, with emphasis on those in east Asia. The CCR2-64I frequencies do not vary significantly in the different continents, having a range of 0.1–0.2 in most populations. A decreasing cline of the CCR2-64I frequency from north to south was observed in east Asia. In contrast, the distribution of SDF1-3′A in world populations varies substantially, and the highest frequency was observed in Oceanian populations. Moreover, an increasing cline of the SDF1-3′A frequency from north to south was observed in east Asia. The relative hazard values were computed to evaluate the risk of AIDS onset on the basis of two-locus genotypes in the east Asian and world populations