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The internalization of Lactobacillus johnsonii N6.2 extracellular vesicles (EVs) by cells results in a significant induction of the 2',5'-oligoadenylate synthetase (OAS) pathway. It also induces expression of IFI44L, MX1, MX2 and DDX60. In this work, we evaluated whether the antiviral response induced by L. johnsonii N6.2-derived EVs, has an inhibitory effect on an RNA viral insult using murine norovirus (MNV-1) as the viral infection model. We found that RAW 264.7 Macrophages treated with EVs significantly decreased the levels of MNV-1 genome. These results were consistent with an increase in expression of Oas1b, Oas2, Oasl, Mx1, Mx2 and Ifi44l (6 hours post infection). Out of six proteins enriched in EVs, we found that SH3b2 domain of Sdp was the only protein effector molecule able to recapitulate the activation of the OAS pathway. In C57BL6 mice, the administration of live L. johnsonii N6.2, EVs, and Sdp-SH3b2/liposomes significantly decreased MNV-1 titers in the distal ileum, in contrast to the controls with PBS and liposomes alone that did not affect MNV-1. These results establish that the SH3b2 domain of Sdp, which is enriched in L. johnsonii derived EVs, is an effector molecule in EVs that can orchestrate the control of viral infections in vivo. [ABSTRACT FROM AUTHOR]

A multivariate nutritional analysis indicated that the consumption of erucic acid-rich food, a fatty acid (FA) found primarily in rapeseed and mustard oil, was positively correlated with higher counts of lactic acid bacteria (LAB). Furthermore, we showed Lactobacillus johnsonii N6.2, as well as other species of LAB tested from the former Lactobacillus genus, were able to efficiently use erucic acid (EA) as the source of FA. In this work, we identified significant changes induced in the FA profiles of L. johnsonii cultured with EA as the source of FA. We performed global transcriptomics to identify genes and pathways involved in EA utilization. It was found that L. johnsonii incorporates external fatty acids via a FakA/FakB and the plsX/plsY/plsC pathway for phosphatidic acid synthesis. It was found that cells grown in MRS with EA (MRS-E) significantly upregulated fakB2 and fakB4 when compared to cells grown in standard MRS with tween 80 as the source of FA. Additionally, in MRS-E, L. johnsonii N6.2 induced the expression of plsY2, plsC2 and plsC4 while the expression of pslX was constitutive during short term EA exposure. LC–MS analyses revealed that L. johnsonii N6.2 rapidly incorporates EA and synthesizes a variety of long chain fatty acids, including the health-relevant omega-9 monounsaturated fatty acids such as nervonic and gondoic acids. [ABSTRACT FROM AUTHOR]

Cells of all domains of life can secrete extracellular vesicles (EV). These secreted vesicles have been indicated as vehicles carrying molecules that facilitate intra- and inter-species interaction. Lactobacillus johnsonii N6.2, a bacterium used in probiotic preparations, has been shown to produce nano-sized EV. In the present work we used L. johnsonii N6.2 EV, concentrated from exosome-depleted MRS supernatant, to identify the uptake mechanisms of EV and the impact of the RNA cargo in the EV on the upregulation of the cellular response of βlox5 human pancreatic cells. Using eukaryotic uptake inhibitors, it was found that EV are internalized by the clathrin/dynamin mediated endocytosis pathway. Further co-localization experiments with the endosome markers RAB5, RAB7 and LAMP1 as well as calcein indicated that EV escape the endosome shortly after RAB7 fusion. Using the expression of the 2',5'-oligoadenylate synthetase (OAS) host pathway, previously identified as targeted by L. johnsonii EV, we found that the host cellular response to the EV are dependent on the integrity of the external components of the EV as well as on the RNA cargo. Global transcriptome analysis was performed on EV and the bacterial whole cell. It was found that the RNA transcripts found within the EV largely represent the most abundantly transcribed genes in the bacterial cells such as those associated with protein synthesis and glycolysis. Further analysis showed an enrichment of smaller size transcripts as well as those encoding for membrane bound or extracellular proteins in L. johnsonii's EV. [ABSTRACT FROM AUTHOR]

Treponema pallidum and Treponema denticola encode within their genomes homologues of energy coupling and regulatory proteins of the phosphoenolpyruvate: sugar phosphotransferase system (PTS) but no recognizable homologues of PTS permeases. The first biochemical description of PTS phosphoryl-transfer chains in an organism that lacks PTS permeases is described.

The isolation of one strain identified as being Lactobacillus johnsonii that exhibited strong ferulic acid esterase (FAE) activity in stool samples from diabetes-resistant biobreeding rats is described. The strain isolated as well as the enzymes are useful for the formulation of probiotics to ameliorate diabetes symptoms.

The purification and biochemical characterization of four predicted glutaminases from Escherichia coli (YbaS and YneH) and Bacillus subtilis (YlaM and YbgJ) is described. The results provide insight into crystal structures of YbaS and YbgJ in free state as well as the structure of the covalent complex of YbgJ with the glutaminase inhibitor 6-diazo-5-oxo-L-nor-leucine and also involvement of YneH in the assimilation of glutamine and the contribution of YneH and YbaS in acid resistance.