Project description:To identify the mechanism of Microbial Influenced Corrosion (MIC) and the bacterial response toward corrosion, we conducted whole genome microarray expression profile. At log phase, the cell of Clostridium carboxidivorans using iron granule as an electron donor (corroding iron) was collected as a sample, and that of using syngas as an electron donor was collected as a control.
Project description:Beside suppressing immune responses, regulatory T cells (Tregs) maintain tissue homeostasis and control systemic metabolism. Whether iron, a fundamental element for all living cells, is required for Treg expansion, is completely unknown. Here, we showed that the transferrin receptor CD71 was upregulated on activated proliferating Tregs infiltrating human liver cancer. Mice with a Treg-restricted CD71 deficiency spontaneously developed a scurfy-like disease, caused by a severe impairment in perinatal Treg expansion. CD71-null Tregs display decreased proliferation and mitochondrial functions, and a tissue-Treg signature loss. In the perinatal life, CD71 deficiency in Tregs triggered a hepatic response to iron overload, characterized by increased hepcidin transcription and iron accumulation in macrophages. A lower bacterial diversity, and a reduction of beneficial species, were detected in the faecal microbiota of CD71 conditional knock-out neonates. Our findings indicate that the CD71-mediated iron absorption is required for Treg perinatal expansion and controls the systemic iron homeostasis, which in turn shapes the bacterial gut colonization.
Project description:To explore the bacterial community profile of the gut of the African palm weevil and to identify the abundance and diversity of lignin degradation-associated bacteria in each gut segment.
Project description:Bacterial regulatory RNAs (sRNAs) are commonly short non-coding RNAs that function as pleiotropic regulators by post-transcriptionally impacting mRNA stability and/or translation. They play significant roles in bacterial physiology and are typically expressed in response to specific environmental stimuli such as nutrient limitation. The bacterial pathogen Staphylococcus aureus faces decreased access to essential metal ions, including iron, in the mammalian host in a process called nutritional immunity. In response to host-mediated iron limitation, S. aureus expresses the sRNA IsrR, which coordinates an iron-sparing response by downregulating the expression of mRNAs coding for iron-requiring proteins. Herein, we utilized MS2-Affinity Purification coupled with RNA Sequencing (MAPS) to reveal the in vivo IsrR interaction network. Analysis of co-purified RNAs revealed previously unpredicted putative IsrR targets coding for proteins associated with iron-requiring processes. We validated that IsrR directly interacts with eight of these targets in vitro. We demonstrate physiological roles for IsrR in mediating heme biosynthesis, aerobic respiration, and the metabolism of oxygen radicals. These activities are critical for pathogenesis, and this study establishes how S. aureus leverages these processes to adapt to iron scarcity, which is commonly encountered in the mammalian host.
Project description:Prochlorococcus contributes significantly to ocean primary productivity. The link between primary productivity and iron in specific ocean regions is well established and iron limitation of Prochlorococcus cell division rates in these regions has been shown. However, the extent of ecotypic variation in iron metabolism among Prochlorococcus and the molecular basis for differences is not understood. Here, we examine the growth and transcriptional response of Prochlorococcus strains, MED4 and MIT9313, to changing iron concentrations. During steady state, MIT9313 sustains growth at an order-of-magnitude lower iron concentration than MED4. To explore this difference, we measured the whole-genome transcriptional response of each strain to abrupt iron starvation and rescue. Only four of the 1159 orthologs of MED4 and MIT9313 were differentially expressed in response to iron in both strains. However, in each strain, the expression of over a hundred additional genes changed, many of which are in labile genomic regions, suggesting a role for lateral gene transfer in establishing diversity of iron metabolism among Prochlorococcus. Furthermore, we found that MED4 lacks three genes near the iron-deficiency-induced gene (idiA) that are present and induced by iron stress in MIT9313. These genes are interesting targets for studying the adaptation of natural Prochlorococcus assemblages to local iron conditions as they show more diversity than other genomic regions in environmental metagenomic databases.
Project description:TIGR4 and R6 bacterial strains of Streptococcus pneumoniae treated and not treated with the iron chelator deferoxamine mesylate (DFO)