Project description:By performing single-cell RNA sequencing (scRNA-seq) analysis on the T cells which stimulated by phageome from normal or severe acute pancreatitis mice, we seek to understand which T cells contribute to the inflammation in pancreatitis. t-distributed stochastic neighbor embedding (tSNE) identified 5 distinct T cell cluster, including effector CD8, naïve CD8, CD4, proliferating CD8 and stem like CD8. Stimulation by different phages did not change the T cell heterogeneity. Comparison of genes revealed a significant enrichment in the cell proliferation after SAP derived phages treatment. Differential gene expression analysis confirmed that SAP derived phages treatment skewed the cell pattern toward more IL-7r expression, while control derived phages treatment induce the IL-22 expression.
Project description:<p>Background: Although the roles of rumen microbiome in milk yield and milk protein synthesis have been widely recognized, knowledge on how ruminal microbiome dynamic changes affect these two traits during the whole lactation is lacking. Phages have been shown to affect the microbiota, but little is known about the shift patterns of ruminal phages and if they may modulate rumen microbiome during lactation. Herein, a longitudinal study was performed to identify the potential roles of ruminal phageome and bacteriome interactions, and metabolic function shift in affecting milk yield and protein content using metagenomic and metabolomic profiling of rumen microbiome from the peak, early and later mid-lactation stages.</p><p>Results: A total of 780 ruminal bacterial phages were identified, which exhibited two primary shifting patterns: 1) decreasing then increasing; 2) decreasing then stabilizing through the lactation. Bacteriome also showed first increasing then stabilizing or continuously decline besides exhibiting two similar shifting patterns to those of phages. By associating the differentially abundant phages with their host bacteria, we observed that significantly increased Lactococcus phage BM13, Corynebacterium phage P1201 and Campylobacter phage CJIE4-5 in peak lactation, along with Lactobacillus phage Lv-1 in early and later mid-lactation, and they were positively correlated with the relative abundance of their hosts. However, significantly increased Bacillus phage BCU4 and the Enterococcus phage phiNASRA1 in early mid-lactation were negatively related to their host abundance. In terms of bacteria, such as Ruminococcus flavefaciens and Faecalibacterium sp. CAG 74 had the highest abundance in peak lactation, whereas most Prevotella species were more abundant in early and later mid-lactation. Notably, ruminal carbohydrate and amino acid metabolism functions were enhanced in early mid-lactation. Further structural equation model and network analysis revealed that abundant Bacillus phage BCU4 and Enterococcus phage phiNASRA1 in early mid-lactation were associated with increased relative abundance of Prevotella species, possibly due to a reduction in Bacillus cereus and Enterococcus faecalis. Additionally, these Prevotella species exhibited positive relationships with rumen metabolites, such as L-phenylalanine, phenylacetylglycine, N-acetyl-D-phenylalanine, as well as propionate content, which contributed to the improved milk protein yield.</p><p>Conclusions: This study revealed the bacteriome and phageome interactions at different lactation stages, and the key phages and bacteria regulating the rumen function and metabolism thus contributing to the milk traits of cows. The potential regulatory roles of phages in affecting the rumen bacteriome suggest that they can be powerful targets for future interventions to improve rumen functions.</p>
Project description:Bacterial populations face the constant threat of viral predation exerted by bacteriophages (or phages). In response, bacteria have evolved a wide range of defense mechanisms against phage challenges. Here, we show that aminoglycosides, a well-known class of antibiotics produced by Streptomyces, are potent inhibitors of phage infection. We observed a broad phage inhibition by aminoglycosides. We demonstrate that aminoglycosides do not prevent the injection of phage DNA into bacterial cells but instead block an early step of the viral life cycle. In this context, we used RNA sequencing of S. venezuelae cells infected with phage Alderaan to comparatively investigate the influence of apramycin on phage DNA tanscription at two different time points after inital infection.
Project description:Virulent bacteriophages (or phages) are viruses that specifically infect and lyse a bacterial host. When multiple phages co-infect a bacterial host, the extent of lysis, dynamics of bacteria-phage and phage-phage interactions are expected to vary. The objective of this study is to identify the factors influencing the interaction of two virulent phages with different Pseudomonas aeruginosa growth states (planktonic, an infected epithelial cell line, and biofilm) by measuring the bacterial time-kill and individual phage replication kinetics. A single administration of phages effectively reduced P. aeruginosa viability in planktonic conditions and infected human lung cell cultures, but phage-resistant variants subsequently emerged. In static biofilms, the phage combination displayed initial inhibition of biofilm dispersal, but sustained control was achieved only by combining phages and meropenem antibiotic. In contrast, adherent biofilms showed tolerance to phage and/or meropenem, suggesting a spatiotemporal variation in the phage-bacterial interaction. The kinetics of adsorption of each phage to P. aeruginosa during single- or co-administration were comparable. However, the phage with the shorter lysis time depleted bacterial resources early and selected a specific nucleotide polymorphism that conferred a competitive disadvantage and cross-resistance to the second phage. The extent and strength of this phage-phage competition and genetic loci conferring phage resistance, are, however, P. aeruginosa genotype dependent. Nevertheless, adding phages sequentially resulted in their unimpeded replication with no significant increase in bacterial host lysis. These results highlight the interrelatedness of phage-phage competition, phage resistance and specific bacterial growth state (planktonic/biofilm) in shaping the interplay among P. aeruginosa and virulent phages.
Project description:Genomic material isolated from purified phage YerA41 lysate was shown to contain RNA. YerA41 phage lysate was RNase treated to remove phage-external RNA and total RNA was then isolated from the phage preparate using Qiagen Rneasy mini kit. The isolated RNA was sequenced to elucidate its origin. The results suggested that the RNA originated from intact ribosomes of the host bacterium that contaminated the phage lysate.
Project description:Extensive molecular and prognostic characterization of wild-type MLL infant ALL. Background: Approximately 20% of all infant ALL cases carry wild-type (or germline) MLL genes. To date, wild-type MLL infant ALL patients are generally regarded as young pediatric precursor B-ALL patients, but extensive characterization of this specific patient group largely remains unacknowledged. Methods: We here studied a relatively large cohort of 78 wild-type MLL infant ALL samples, using clinical parameters, array-comparative genomic hybridization analysis, gene expression profiling, multiplex ligation-dependent probe amplification, and conventional sequencing. Findings: Wild-type MLL infant ALL patients are generally characterized by a lower incidence of favourable prognostic factors than pediatric (non-infant) B-ALL patients, and patients at high risk of therapy failure typically display an immature pro-B immunophenotype or respond poorly to prednisone. Using gene expression profiling, we found MEIS1 expression to additionally be highly predictive for clinical outcome in wild-type MLL infant ALL with a favourable prognosis in the wild-type MLL infants with low MEIS1 expression (DFS 88%% versus 50%, p=0•01). Overall the incidence of DNA copy number variations and genetic abnormalities in genes involved in B-cell differentiation is lower in wild-type MLL infant ALL patients as compared with pediatric precursor B-ALL patients. Interpretation: Wild-type MLL infant ALL represents a highly heterogeneous patient group, which cannot be unified by one or a few known recurrent genomic aberrations. High-level MEIS1 expression and an immature pro-B immunophenotype in high-risk wild-type MLL infant ALL patients shows parallel with the unfavourable prognosis of MLL-rearranged infant ALL patients. In contrast, wild-type MLL infant ALL patients expressing lower levels of MEIS1 and displaying more differentiated (pre-B or common) phenotypes may well be more related to pediatric precursor B-ALL patients older than 1 year of age. We advocate that a treatment strategy in wild-type MLL infant ALL based on MEIS1 expression could be beneficial for improving survival. Gene expression profiling of wild-type MLL infant ALL. Additional wild-type MLL infant ALL patient samples (n=17) to the earlier samples published under GSE19475 (GSM485309 to GSM485322).
Project description:To better understand host/phage interactions and the genetic bases of phage resistance in a model system relevant to potential phage therapy, we isolated several spontaneous mutants of the USA300 S. aureus clinical isolate NRS384 that were resistant to phage K. Six of these had a single missense mutation in the host rpoC gene, which encodes the RNA polymerase beta prime subunit. To examine the hypothesis that the mutations in the host RNA polymerase affect the transcription of phage genes, we performed RNA-seq analysis on total RNA samples collected from NRS384 wild-type (WT) and rpoC G17D mutant cultures infected with phage K, at different time points after infection. Infection of the WT host led to a steady increase of phage transcription relative to the host. Our analysis allowed us to define different early, middle, and late phage genes based on their temporal expression patterns and group them into transcriptional units. Predicted promoter sequences defined by conserved -35, -10, and in some cases extended -10 elements were found upstream of early and middle genes. However, sequences upstream of late genes did not contain clear, complete, canonical promoter sequences, suggesting that factors in addition to host RNA polymerase are required for their regulated expression. Infection of the rpoC G17D mutant host led to a transcriptional pattern that was similar to the WT at early time points. However, beginning at 20 minutes after infection, transcription of late genes (such as phage structural genes and host lysis genes) was severely reduced. Our data indicate that the rpoCG17D mutation prevents the expression of phage late genes, resulting in a failed infection cycle for phage K. In addition to illuminating the global transcriptional landscape of phage K throughout the infection cycle, these studies can inform our investigations into the bases of phage K’s control of its transcriptional program as well as mechanisms of phage resistance.
Project description:The aggressive MLL-rearranged leukemias are well-known for their unique gene-expression profiles. The goal of this study was to characterize the MLL-specific DNA methylation profiles in infant acute lymphoblastic leukemia (ALL). Genome-wide DNA methylation profiling was performed on primary infant ALL samples. The majority of infant ALL samples demonstrated severe DNA hypermethylation compared with normal pediatric bone marrows, which implies that targeting of DNA methylation may be an interesting option for future therapeutic strategies in MLL-rearranged infant ALL. Using ALL cell lines carrying the MLL translocation t(4;11) (SEMK2 and RS4;11) as a model for the patient cells, we demonstrated that the hypermethylated genes are sensitive to demethylation.