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: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)
Project description:The iron-binding glycoprotein lactoferrin exhibits anti-bacterial activity. To investigate the overall response of Bacillus cereus to lactoferrin, total transcriptome analyses were performed. Growth conditions were mMOD minimal medium, minimal medium plus 10 mg/ml lactoferrin, as well as minimal medium without iron source for comparison. Differential regulation of genes involved in iron acquisition as well as genes encoding enterotoxins and further virulence factors was of special interest.
Project description:Leptospirosis is a globally significant zoonotic disease caused by Leptospira spp. Iron is essential for growth of most bacterial species. Since availability of iron is low in the host, pathogens have evolved complex iron acquisition mechanisms to survive and establish infection. Virulence genes in some bacteria have been shown to be iron-regulated. In many bacteria, expression of iron-uptake and storage proteins is regulated by Fur. L. interrogans encodes four predicted Fur homologs; we have constructed a mutant in one of these, la1857. We conducted microarray analysis to identify differentially expressed genes in L. interrogans serovar Manilae grown under low iron compared with normal iron conditions found in EMJH medium. We also compared the transcriptional profile of the la1857 mutant versus wild-type Manilae under normal and low iron conditions.