Project description:Levoglucosan is produced in the pyrolysis of cellulose and starch, including from bushfires or the burning of biofuels, and is deposited from the atmosphere across the surface of the earth. We describe two levoglucosan degrading Paenarthrobacter spp. (Paenarthrobacter nitrojuajacolis LG01 and Paenarthrobacter histidinolovorans LG02) that were isolated by metabolic enrichment on levoglucosan as sole carbon source. Genome sequencing and proteomics analysis revealed expression of a series of gene clusters encoding known levoglucosan degrading enzymes, levoglucosan dehydrogenase (LGDH, LgdA), 3-keto-levoglucosan b-eliminase (LgdB1) and glucose 3-dehydrogenase (LgdC), along with an ABC transporter cassette and associated solute binding protein. However, no homologues of 3-ketoglucose dehydratase (LgdB2) were evident. The expressed gene clusters contained a range of putative sugar phosphate isomerase/xylose isomerases with weak similarity to LgdB2. Sequence similarity network analysis of genome neighbors revealed that homologues of LgdA, LgdB1 and LgdC are generally conserved in a range of bacteria in the phyla Firmicutes, Actinobacteria and Proteobacteria. One sugar phosphate isomerase/xylose isomerase cluster (LgdB3) was identified with limited distribution mutually exclusive with LgdB2. LgdB1, LgdB2 and LgdB3 adopt similar predicted 3D folds suggesting overlapping function in processing intermediates in LG metabolism. Our findings highlight the diversity within the LGDH pathway through which bacteria utilize levoglucosan as a nutrient source.
Project description:Comparative proteomics of Bacteroides thetaiotaomicron samples comparing the total membrane (TM) and outer membrane vesicles (OMV) of WT B. thetaiotaomicron and delta 4364
Project description:This project examines the impact of different growth media on the protein compositions of membranes of Bacteroides thetaiotaomicron.
Project description:Within the Burkholderia genus O-linked protein glycosylation is now known to be highly conserved at the pathway and glycosylation substrate levels. While inhibition of glycosylation has been shown to be detrimental to virulence in B. cenocepacia, little is known about the role of glycosylation in Burkholderia glycoproteins. Within this study we have sought to improve our understanding of the breadth and dynamics of the B. cenocepacia O-glycoproteome to identify glycoproteins which require glycosylation for functionality. Assessing the glycoproteome across multiple common culturing media (LB, TSB, and artificial sputum medium to simulate cystic fibrosis sputum-like conditions) we demonstrate at least 141 glycoproteins are subjected to glycosylation within B. cenocepacia K56-2. Leveraging this insight, we quantitively assessed the glycoproteome of B. cenocepacia using Data-Independent Acquisition (DIA) across culturing media and growth phases revealing most B. cenocepacia glycoproteins are express under all conditions. Examination of how the absence of glycosylation impacts the glycoproteome reveals only a subset of the glycoproteome (BCAL1086, BCAL2974, BCAL0525, BCAM0505 and BCAL0127) appear impacted by the loss of glycosylation. Assessing the proteomic and phenotypic impacts of the loss of these glycoproteins compared to glycosylation null strains revealing the loss of BCAL0525, and to a lesser extend BCAL0127, mirror the proteomic effects observed in the absence of glycosylation. Finally, we demonstrate the loss of glycosylation within BCAL0525 at Serine-358 results in both loss of motility and proteomic impacts on flagellar apparatus consistent with the loss of apparatus stability. Combined this work demonstrates that O-linked glycosylation of BCAL0525 is functionally important within B. cenocepacia.
Project description:Within the Burkholderia genus O-linked protein glycosylation is now known to be highly conserved at the pathway and glycosylation substrate levels. While inhibition of glycosylation has been shown to be detrimental to virulence in B. cenocepacia, little is known about the role of glycosylation in Burkholderia glycoproteins. Within this study we have sought to improve our understanding of the breadth and dynamics of the B. cenocepacia O-glycoproteome to identify glycoproteins which require glycosylation for functionality. Assessing the glycoproteome across multiple common culturing media (LB, TSB, and artificial sputum medium to simulate cystic fibrosis sputum-like conditions) we demonstrate at least 141 glycoproteins are subjected to glycosylation within B. cenocepacia K56-2. Leveraging this insight, we quantitively assessed the glycoproteome of B. cenocepacia using Data-Independent Acquisition (DIA) across culturing media and growth phases revealing most B. cenocepacia glycoproteins are express under all conditions. Examination of how the absence of glycosylation impacts the glycoproteome reveals only a subset of the glycoproteome (BCAL1086, BCAL2974, BCAL0525, BCAM0505 and BCAL0127) appear impacted by the loss of glycosylation. Assessing the proteomic and phenotypic impacts of the loss of these glycoproteins compared to glycosylation null strains revealing the loss of BCAL0525, and to a lesser extend BCAL0127, mirror the proteomic effects observed in the absence of glycosylation. Finally, we demonstrate the loss of glycosylation within BCAL0525 at Serine-358 results in both loss of motility and proteomic impacts on flagellar apparatus consistent with the loss of apparatus stability. Combined this work demonstrates that O-linked glycosylation of BCAL0525 is functionally important within B. cenocepacia.
Project description:Enterobacter bugandensis is one of species from the E. cloacae complex (ECC) that has been predominantly associated to neonatal sepsis. A major concern with E. bugandensis and ECC bacteria in general is the frequent appearance of multidrug resistant isolates including those resistant to last-resort antibiotics, such as polymyxins, for which these microbes are in the ESKAPE list of global threat pathogens. Here, we investigated polymyxin B (PmB) resistance and heteroresistance in E. bugandensis by transcriptomics and a gene deletion approach using two clinical isolates. Genes encoded in the CrrAB-regulated operon including crrC and kexD were highly upregulated in both strains in the presence of PmB. We show in one of these isolates that ∆crrC and ∆kexD mutants exhibited lower levels of PmB resistance and heteroresistance than the parental strain. Moreover, the heterologous expression of CrrC and KexD proteins increased PmB resistance in a sensitive E. ludwigii clinical isolate and in the Escherichia coli K12 strain W3110. We also showed that the efflux pump AcrAB and TolC contribute to PmB resistance and heteroresistance. Deletion of the regulatory genes phoPQ and crrAB cause reduced PmB resistance and heteroresistance, while deletion of pmrAB did not have any effect. Our results also reveal that the addition of L-Ara4N into the lipid A, mediated by the arnBCADTEF operon, is critical to determine PmB resistance, while the deletion of eptA, encoding a PEtN transferase had no effect. Finally, PmB resistance did not correlate with pathogenicity in the Galleria mellonella infection model.
Project description:Proteomic investigation on the glycosylation substrates and proteome effects of altering neisserial OTases within the proteome of N. gonorrhoeae MS11
Project description:Cryptosporidium parvum is a zoonotic apicomplexan parasite and a common cause of diarrheal disease worldwide. The development of vaccines to prevent or limit infection remains an important goal for tackling these diarrheal diseases, which are a significant cause of infant morbidity in the developing world. The only approved vaccine against an apicomplexan parasite targets conserved adhesins possessing a thrombospondin repeat (TSR) domains. Orthologous TSR domain-containing proteins are commonplace in the apicomplexa and C. parvum possess 12 such proteins. Here, we explore the molecular evolution and conservation of these proteins and examine their abundance in C. parvum oocysts to assess the likelihood that they may be useful as vaccine candidates. We go onto examine the glycosylation states of these proteins using antibody-enabled and ZIC-HILIC enrichment techniques, which revealed that these proteins are modified with C-linked Hex and N-linked Hex5-6HexNAc2 glycans.
Project description:Objective: The developmental effects of mutations in genes associated with monogenic diabetes on human pancreas development is not well understood. More specifically, if insulin gene recessive mutations influence the human endocrine lineage segregation still needs to be investigated. Methods: We generated a novel knock-in H2B-Cherry reporter human induced pluripotent stem cell (iPSCs) line expressing no insulin upon differentiation to stem cell-derived (SC-) β cells in vitro. This cell line enabled us to have a model mimicking the extremely reduced insulin levels in patients with recessive insulin mutations. We combined immunostaining, Western blotting and proteomics analysis to characterize the SC-islets from this iPSC line. Furthermore, we leveraged FACS analysis and imaging to explore the impact of insulin shortage on human endocrine cell induction, composition and proliferation. Results: We found that lack of insulin hampers insulin receptor (IR) signaling in SC-islets but increases the IR sensitivity. Furthermore, insulin deficiency showed no effects on human endocrine lineage induction. However, lack of insulin skewed the SC-islet cell composition. We found an increased in SC-β cell number at the expense of SC-α cell differentiation in the absence of insulin. Finally, insulin shortage reduced the rate of SC-β cell proliferation but had no impact of the expansion of SC-α cells. Conclusions: We provided evidence of the developmental impacts of reduced insulin levels on human β cell characteristics and endocrine lineage formation. These findings help to better understand the pathomechanisms of recessive insulin mutations during embryonic development and also shed some lights on the possible physiological function of this hormone coordinating human islet cell composition and architecture during endocrinogenesis.
Project description:In this paper we investigate one of the lesser studied TRIM family proteins, TRIM16, to determine if it might impact the ability of different viruses to replicate productively in host cells. TRIM16 is unique compared to other TRIM proteins in that it mediates E3 ligase activity despite lacking the catalytic RING domain present in other TRIM proteins. TRIM16 has been shown to play a role in innate immunity by increasing the secretion proinflammatory cytokine Il-1 in macrophages through interactions with components of the inflammasome complex (procaspase-1 and NALP-1). TRIM16 also mediates ubiquitination and aggregation of misfolded proteins which are subsequently degraded through the autophagic pathway in cells under proteotoxic and oxidative stress11. It does so through interactions with the p62-KEAP-NRF2 complex and stabilization of the NRF2 protein through multiple mechanisms11. Interestingly the NRF2 protein has been implicated in antiviral immunity, as previous studies have shown that infection of NRF2 (-/-) mice with respiratory syncytial virus (RSV) resulted in significantly higher viral titres in the lungs compared to NRF2 (+/+) mice. In addition to these clues in the literature, a recent study from our group examining transcriptional signatures in type II airway epithelial cells (AEC II) isolated from mock versus IAV-infected mice indicated that TRIM16 was upregulated in AECII following IAV infection in vivo.