Genome-Wide Effects of Selenium and Translational Uncoupling on Transcription in the Termite Gut Symbiont Treponema primitia

When prokaryotic cells acquire mutations, encounter translation-inhibiting substances, or experience adverse environmental conditions that limit their ability to synthesize proteins, transcription can become uncoupled from translation. Such uncoupling is known to suppress transcription of protein-encoding genes in bacteria. Here we show that the trace element selenium controls transcription of the gene for the selenocysteine-utilizing enzyme formate dehydrogenase (fdhF_Sec) through a translation-coupled mechanism in the termite gut symbiont Treponema primitia, a member of the bacterial phylum Spirochaetes. We also evaluated changes in genome-wide transcriptional patterns caused by selenium limitation and by generally uncoupling translation from transcription via antibiotic-mediated inhibition of protein synthesis. We observed that inhibiting protein synthesis in T. primitia influences transcriptional patterns in unexpected ways. In addition to suppressing transcription of certain genes, the expected consequence of inhibiting protein synthesis, we found numerous examples in which transcription of genes and operons is truncated far downstream from putative promoters, is unchanged, or is even stimulated overall. These results indicate that gene regulation in bacteria allows for specific post-initiation transcriptional responses during periods of limited protein synthesis, which may depend both on translational coupling and on unclassified intrinsic elements of protein-encoding genes. A large body of literature demonstrates that the coupling of transcription and translation is a general and essential method by which bacteria regulate gene expression levels. However, the potential role of noncanonical amino acids in regulating transcriptional output via translational control remains, for the most part, undefined. Furthermore, the genome-wide transcriptional state in response to translational decoupling is not well quantified. The results presented here suggest that the noncanonical amino acid selenocysteine is able to tune transcription of an important metabolic gene via translational coupling. Furthermore, a genome-wide analysis reveals that transcriptional decoupling produces a wide-ranging effect and that this effect is not uniform. These results exemplify how growth conditions that impact translational processivity can rapidly feed back on transcriptional productivity of prespecified groups of genes, providing bacteria with an efficient response to environmental changes

Building Resilience in a Major City Evacuation Plan Using Simulation Modeling

This study provides data on the optimal staff, materials, space, and time resources required to operate a regional hub reception center, a “short-term facility with the goal to process and transport displaced survivors (evacuees) to temporary or permanent shelters following a catastrophic incident,” (Regional Catastrophic Planning Team, 2012). The facility will process approximately 20,000 evacuees over its entire seven-day duration following a disaster to assist in community resilience. The study was performed using a model created using the computer simulation software, AnyLogic. The results of the study demonstrated that the goals set forth by the Illinois-Indiana-Wisconsin Regional Catastrophic Planning Team could be improved upon and that the largest contributing factor to optimizing the RHRC is finding the optimal number of total staff members to operate the facility

Breast Milk Stem Cells: Current Science and Implications for Preterm Infants

Background: The benefits of breast milk are well described, yet the mechanistic details related to how breast milk protects against acute and chronic diseases and optimizes neurodevelopment remain largely unknown. Recently, breast milk was found to contain stem cells that are thought to be involved in infant development. Purpose: The purpose of this review was to synthesize all available research involving the characterization of breast milk stem cells to provide a basis of understanding for what is known and what still needs further exploration. Methods/Search Strategy: The literature search was conducted between August and October 2015 using the CINAHL, PubMed, and reference list searching. Nine studies addressed characterization of human breast milk stem cells. Findings/Results: Five research teams in 4 countries have published studies on breast milk stem cells. Current research has focused on characterizing stem cells in full-term breast milk. The amount, phenotype, and expression of breast milk stem cells are known to vary between mothers, and they have been able to differentiate into all 3 germ layers (expressing pluripotent characteristics). Implications for Practice: There is much to learn about breast milk stem cells. Given the potential impact of this research, healthcare professionals should be aware of their presence and ongoing research to determine benefits for infants. Implications for Research: Extensive research is needed to further characterize stem cells in breast milk (full-term and preterm), throughout the stages of lactation, and most importantly, their role in the health of infants, and potential for use in regenerative therapies

Matson, S. W. & Robertson, A. B. The UvrD helicase and its modulation by the mismatch repair protein MutL. Nucleic Acids Res. 34, 4089-4097

UvrD is a superfamily I DNA helicase with well documented roles in excision repair and methyl-directed mismatch repair (MMR) in addition to poorly understood roles in replication and recombination. The MutL protein is a homodimeric DNA-stimulated ATPase that plays a central role in MMR i

IgG transmitted from allergic mothers decreases allergic sensitization in breastfed offspring

<p>Abstract</p> <p>Background</p> <p>The mechanism(s) responsible for the reduced risk of allergic disease in breastfed infants are not fully understood. Using an established murine model of asthma, we demonstrated previously that resistance to allergic airway disease transmitted from allergic mothers to breastfed offspring requires maternal B cell-derived factors.</p> <p>Objective</p> <p>The aim of this study was to investigate the role of offspring neonatal Fc receptor for IgG uptake by intestinal epithelial cells (FcRn) in this breast milk transferred protection from allergy.</p> <p>Methods</p> <p>Allergic airway disease was induced during pregnancy in C57BL/6 female mice. These allergic mothers foster nursed naive FcRn^+/-or FcRn^-/-progeny born to FcRn^+/-females that were mated to C57BL/6J-FcRn^-/-male mice. In offspring deficient in FcRn, we expected reduced levels of systemic allergen-specific IgG₁, a consequence of decreased absorption of maternal IgG from the lumen of the neonatal gastrointestinal tract. Using this model, we were able to investigate how breast milk IgG affected offspring responses to allergic sensitization.</p> <p>Results</p> <p>Levels of maternal antibodies absorbed from the breast milk of allergic foster mothers were determined in weanling FcRn-sufficient or -deficient mice. Maternal transmission of allergen-specific IgG₁to breastfed FcRn^-/-offspring was at levels 10³-10⁴lower than observed in FcRn^+/-or FcRn^+/+mice. Five weeks after weaning, when offspring were 8 wk old, mice were sensitized and challenged to evaluate their susceptibility to develop allergic airway disease. Protection, indicated by reduced parameters of disease (allergen-specific IgE in serum, eosinophilic inflammation in the airways and lung) were evident in FcRn-sufficient mice nursed as neonates by allergic mothers. In contrast, FcRn-deficient mice breastfed by the same mothers acquired limited, if any, protection from development of allergen-specific IgE and associated pathology.</p> <p>Conclusions</p> <p>FcRn expression was a major factor in determining how breastfed offspring of allergic mothers acquired levels of systemic allergen-specific IgG₁sufficient to inhibit allergic sensitization in this model.</p

MutL-catalyzed ATP Hydrolysis Is Required at a Post-UvrD Loading Step in Methyl-directed Mismatch Repair

Methyl-directed mismatch repair is a coordinated process that ensures replication fidelity and genome integrity by resolving base pair mismatches and insertion/deletion loops. This post-replicative event involves the activities of several proteins, many of which appear to be regulated by MutL. MutL interacts with and modulates the activities of MutS, MutH, UvrD, and perhaps other proteins. The purified protein catalyzes a slow ATP hydrolysis reaction that is essential for its role in mismatch repair. However, the role of the ATP hydrolysis reaction is not understood. We have begun to address this issue using two point mutants: MutL-E29A, which binds nucleotide but does not catalyze ATP hydrolysis, and MutL-D58A, which does not bind nucleotide. As expected, both mutants failed to complement the loss of MutL in genetic assays. Purified MutL-E29A protein interacted with MutS and stimulated the MutH-catalyzed nicking reaction in a mismatch-dependent manner. Importantly, MutL-E29A stimulated the loading of UvrD on model substrates. In fact, stimulation of UvrD-catalyzed unwinding was more robust with MutL-E29A than the wild-type protein. MutL-D58A, on the other hand, did not interact with MutS, stimulate MutH-catalyzed nicking, or stimulate the loading of UvrD. We conclude that ATP-bound MutL is required for the incision steps associated with mismatch repair and that ATP hydrolysis by MutL is required for a step in the mismatch repair pathway subsequent to the loading of UvrD and may serve to regulate helicase loading

Maternal Transmission of Resistance to Development of Allergic Airway Disease

Parental phenotype is known to influence the inheritance of atopic diseases, such as allergic asthma, with a maternal history being a more significant risk factor for progeny than paternal history. We hypothesized that recall Th1- or Th2-type immune responses during pregnancy would result in transfer of maternal factors that would differentially impact development of immune responsiveness in offspring. Following weaning, susceptibility and severity of allergic airway disease (a murine model of human asthma) was evaluated in progeny, disease being elicited by immunization with OVA-Al(OH)3 and challenge with aerosolized OVA. We found that progeny of mothers with Th1-biased immunity to OVA subjected to recall aerosol challenge during pregnancy had reduced levels of Ag-specific IgE and airway eosinophilia compared with progeny of mothers with Th2-biased immunity to OVA or naive mothers. Interestingly, progeny of mothers with Th1-type immunity to a heterologous albumin, BSA, were not protected from developing OVA-induced allergic airway disease. These findings demonstrated that maternal transfer of protection from development of allergic airway disease to offspring in this model of maternal Th1-type immunity was Ag specific

High-resolution microbiome analysis reveals exclusionary Klebsiella species competition in preterm infants at risk for necrotizing enterocolitis.

Intestinal colonization with Klebsiella has been linked to necrotizing enterocolitis (NEC), but methods of analysis usually failed to discriminate Klebsiella species or strains. A novel ~ 2500-base amplicon (StrainID) that spans the 16S and 23S rRNA genes was used to generate amplicon sequence variant (ASV) fingerprints for Klebsiella oxytoca and Klebsiella pneumoniae species complexes (KoSC and KpSC, respectively) and co-occurring fecal bacterial strains from 10 preterm infants with NEC and 20 matched controls. Complementary approaches were used to identify cytotoxin-producing isolates of KoSC. Klebsiella species colonized most preterm infants, were more prevalent in NEC subjects versus controls, and replaced Escherichia in NEC subjects. Single KoSC or KpSC ASV fingerprinted strains dominated the gut microbiota, suggesting exclusionary Klebsiella competition for luminal resources. Enterococcus faecalis was co-dominant with KoSC but present infrequently with KpSC. Cytotoxin-producing KoSC members were identified in most NEC subjects and were less frequent in controls. Few Klebsiella strains were shared between subjects. We conclude that inter-species Klebsiella competition, within an environment of KoSC and E. faecalis cooperation, appears to be an important factor for the development of NEC. Preterm infants seem to acquire Klebsiella primarily through routes other than patient-to-patient transmission

Bromelain Inhibits Allergic Sensitization and Murine Asthma via Modulation of Dendritic Cells

The incidence of atopic conditions has increased in industrialized countries. Persisting symptoms and concern for drug side-effects lead patients toward adjunctive treatments such as phytotherapy. Previously, we have shown that Bromelain (sBr), a mixture of cysteine proteases from pineapple, Ananas comosus, inhibits ovalbumin (OVA)-induced murine model of allergic airway disease (AAD). However, sBr’s effect on development of AAD when treatment is administered throughout OVA-alum sensitization was unknown and is the aim of the present study. C57BL/6J mice were sensitized with OVA/alum and challenged with 7 days OVA aerosol. sBr 6 mg/kg/0.5 ml or PBS vehicle were administered throughout sensitization. Lung, bronchoalveolar lavage (BAL), spleen, and lymph nodes were processed for flow cytometry and OVA-specific IgE was determined via ELISA. sBr treatment throughout OVA-alum sensitization significantly reduced the development of AAD (BAL eosinophils and lymphocytes). OVA-specific IgE and OVA TET+ cells were decreased. sBr reduced CD11c+ dendritic cell subsets, and in vitro treatment of DCs significantly reduced CD44, a key receptor in both cell trafficking and activation. sBr was shown to reduce allergic sensitization and the generation of AAD upon antigen challenge. These results provide additional insight into sBr's anti-inflammatory and antiallergic properties and rationale for translation into the clinical arena