Characterization of a Novel Group of Listeria Phages That Target Serotype 4b Listeria monocytogenes

Listeria monocytogenes serotype 4b strains are the most prevalent clinical isolates and are widely found in food processing environments. Bacteriophages are natural viral predators of bacteria and are a promising biocontrol agent for L. monocytogenes. The aims of this study were to characterize phages that specifically infect serotype 4b strains and to assess their ability to inhibit the growth of serotype 4b strains. Out of 120 wild Listeria phages, nine phages were selected based on their strong lytic activity against the model serotype 4b strain F2365. These nine phages can be divided into two groups based on their morphological characteristics and host range. Comparison to previously characterized phage genomes revealed one of these groups qualifies to be defined as a novel species. Phages LP-020, LP-027, and LP-094 were selected as representatives of these two groups of phages for further characterization through one-step growth curve and inhibition of serotype 4b L. monocytogenes experiments. Listeria phages that target serotype 4b showed an inhibitory effect on the growth of F2365 and other serotype 4 strains and may be useful for biocontrol of L.monocytogenes in food processing environments.     

Allostatic load,metabolic syndrome and self-rated health in overweight/obese Non-Hispanic White,non-Hispanic Black and Mexican American adults

AimThis study examined the associations of high allostatic load (h_ALS) and metabolic syndrome (MetS) with and self-rated poor health (SRPH) in overweight/obese non-Hispanic White (NHW), non-Hispanic Black (NHB), and Mexican American (MA) adults.MethodsThe 2015–16 and 2017-18 US National Health and Nutrition Examination Survey data (n = 4403) were used for this study.ResultsRates of h_ALS in overweight/obese NHW, NHW, and MA participants were 56.9%, 58.8%, and 51.9%, respectively (P < .05). The corresponding rates for MetS were 26.9%, 31.9%, and 46.5%, respectively. High ALS was associated with 2.19 (95% CI: 1.87–4.59), 1.82 (1.42–2.58), and 1.47 (95% CI: 1.08–1.64) increased odds of SRPH in overweight/obese NHW, NHB, and MA, respectively, after adjusting for age, education, gender, income, lifestyle behaviors, and marital status. The corresponding values for MetS were 1.86 (95% CI: 1.54–2.40), 2.77 (95% CI: 1.36–5.63), and 1.22 (95% CI: 1.06–2.32), respectively.ConclusionsThe effect of h_ALS on SRPH was much stronger in NHW, while the effect of MetS was strongest among NHB overweight/obese adults. The result of this study provides further evidence in favor of race/ethnic-tailored interventions, including education and weight control to reduced risks of bodywear and tear and SRPH.     

Potential of Bacillus sp. LG7 as a Promising Source of Ligninolytic Enzymes for Industrial and Biotechnological Applications

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Ligninolytic bacteria are considered a major source of ligninolytic enzymes, which are widely used in a...     

Benchmarking life quality support interventions in long‐term care using the Long‐Term Care Quality of Life scale

We aimed to develop a graphical procedure for benchmarking quality of life care results using the Long‐Term Care Quality of Life (LTC‐QoL) scale. While clinical care quality benchmarking is now well established, similar research for quality of life (QOL) aged care benchmarking has received scant attention. Data from 10 facilities utilizing the LTC‐QoL scale were analysed to establish baseline statistics for developing a graphical procedure for QOL benchmarking. Client LTC‐QoL records were tested with varimax rotation factor analysis revealing three viable benchmarking themes: B1 (Self‐efficacy), B2 (supporting relationships), and B3 (outlook on life) were selected for benchmark development utilizing Analysis of Means to generate graphical outputs using Minitab version 17.3.1. In this way, in the absence of verified industry standards, it is possible to compare organizations providing similar services using the same indicators, against group averages. In conclusion, the benchmarking protocol produced comparative information on three benchmarks for 10 facilities. Similar analysis is feasible for a single facility over time. The results of these analyses provide evidence for on‐site discussion of quality of life care quality performance.     

Functionally distinct dendritic cell (DC) populations induced by physiologic stimuli: prostaglandin E(2) regulates the migratory capacity of specific DC subsets

Migration of antigen (Ag)-loaded dendritic cells (DCs) from sites of infection into draining lymphoid tissues is fundamental to the priming of T-cell immune responses. We evaluated monocyte-derived DCs (MoDCs) and peripheral blood DCs (PBDCs) to respond to proinflammatory mediators, CD40L, and intact bacteria. All classes of stimuli induced DC phenotypic maturation. However, for MoDCs, only prostaglandin E(2) (PGE(2))-containing stimuli induced migratory-type DCs. Thus, immature MoDCs that encountered proinflammatory cytokines or CD40L or intact bacteria in the presence of PGE(2) acquired migratory capacity but secreted low levels of cytokines. Conversely, MoDCs that encountered pathogens or CD40L alone become nonmigratory cytokine-secreting cells (proinflammatory type). Interestingly, both migratory- and proinflammatory-type DCs expressed equivalent levels of chemokine receptors, suggesting that the role of PGE(2) was to switch on migratory function. We demonstrate that PGE(2) induces migration via the E-prostanoid 2/E-prostanoid 4 (EP(2)/EP(4)) receptors and the cAMP pathway. Finally, migratory-type MoDCs stimulated T-cell proliferation and predominantly IL-2 secretion, whereas proinflammatory-type MoDCs induced IFN-gamma production. In contrast, CD1b/c(+) PBDC rapidly acquired migratory capacity irrespective of the class of stimulus encountered and secreted low levels of cytokines. This suggests that not all mature stages of DCs are destined to migrate to lymphoid organs and that the sequence in which stimuli are encountered significantly affects which functions are expressed. Thus, certain immature DC subsets recruited from the resting precursor pool may have multiple functional fates that play distinct roles during the induction and effector phases of the immune response. These findings have important implications for the clinical utility of DCs in immunotherapy.     

Comparison of the normal sinus node with seven types of rate responsive pacemaker during everyday activity

The heart rate response of 59 patients aged 17-79 years implanted with seven different types of rate responsive pacemakers was evaluated during graded exercise treadmill testing and during standardised daily activities. The heart rate response in patients with pacemakers was compared with the chronotropic response in 20 healthy controls of similar age and sex distribution who performed identical protocols. All pacemaker types adequately simulated the control heart rate response during the graded exercise treadmill test except during the early stages of exercise. However, during everyday activities, the response of ventricular rate responsive (VVIR) pacemakers was varied. Activity sensing systems rapidly overresponded to staircase descent, to changes in walking speed, and to suitcase lifting with the pacemaker arm, and these systems did not respond to mental stress. "Physiological" sensors (QT and minute ventilation units) responded slowly to rapid changes in physiological demand. The QT pacemaker patients did respond to mental stress but showed a paradoxical increase in rate during the recovery phases of burst exercise protocols such as staircase ascent/descent and walking deceleration. Dual chamber pacemakers in VDD, DDD, and DDDR modes most closely simulated the normal chronotropic response during everyday activities. Graded exercise treadmill testing, in isolation, may not be the best way to asses or program the heart rate response in patients with the heart rate adaptive pacemakers because changes in heart rate during everyday activities may deviate considerably from the normal sinus response despite satisfactory simulation of the normal chronotropic response during treadmill testing.     

Role of adenosine receptors in regulating chemotaxis and cytokine production of plasmacytoid dendritic cells

Plasmacytoid dendritic cells (PDCs) are potent regulators of immune function and the major source of type I interferon (IFN) following viral infection. PDCs are found at sites of inflammation in allergic reactions, autoimmune disorders, and cancer, but the mechanisms leading to the recruitment of PDCs to these sites remain elusive. During inflammation, adenosine is released and functions as a signaling molecule via adenosine receptors. This study analyzes adenosine receptor expression and function in human PDCs. Adenosine was found to be a potent chemotactic stimulus for immature PDCs via an A(1) receptor-mediated mechanism. The migratory response toward adenosine was comparable to that seen with CXCL12 (stromal-derived factor-1 alpha [SDF-1 alpha), the most potent chemotactic stimulus identified thus far for immature PDCs. Upon maturation, PDCs down-regulate the A(1) receptor, resulting in a loss of migratory function. In contrast, mature PDCs up-regulate the A(2a) receptor, which is positively coupled to adenylyl cyclase and has been implicated in the down-regulation of DC cytokine-producing capacity. We show that in mature PDCs adenosine reduces interleukin-6 (IL-6), IL-12, and IFN-alpha production in response to CpG oligodeoxynucleotides (ODN). These findings indicate that adenosine may play a dual role in PDC-mediated immunity by initially recruiting immature PDCs to sites of inflammation and by subsequently limiting the extent of the inflammatory response induced by mature PDCs by inhibiting their cytokine-producing capacity.     

Xenotransplantation of immunodeficient mice with mobilized human blood CD34+ cells provides an in vivo model for human megakaryocytopoiesis and platelet production

The study of megakaryocytopoiesis has been based largely on in vitro assays. We characterize an in vivo model of megakaryocyte and platelet development in which human peripheral blood stem cells (PBSCs) differentiate along megakaryocytic as well as myeloid/lymphoid lineages in sublethally irradiated nonobese diabetic/severe combined immunodeficient (NOD-SCID) mice. Human hematopoiesis preferentially occurs in the bone marrow of the murine recipients, and engraftment is independent of exogenous cytokines. Human colony-forming units-megakaryocyte (CFU-MK) develop predominantly in the bone marrow, and their presence correlates with the overall degree of human cell engraftment. Using a sensitive and specific flow cytometric assay, human platelets are detected in the peripheral blood from weeks 1 to 8 after transplantation. The number of circulating human platelets peaks at week 3 with a mean of 20 x 10(9)/L. These human platelets are functional as assessed by CD62P expression in response to thrombin stimulation in vitro. Exogenous cytokines have a detrimental effect on CFU-MK production after 2 weeks, and animals treated with these cytokines have no circulating platelets 8 weeks after transplantation. Although cytokine stimulation of human PBSCs ex vivo led to a significant increase in CFU-MK, CD34+/41+, and CD41+ cells, these ex vivo expanded cells provided only delayed and transient platelet production in vivo, and no CFU-MK developed in vivo after transplantation. In conclusion, xenogeneic transplantation of human PBSCs into NOD/SCID mice provides an excellent in vivo model to study human megakaryocytopoiesis and platelet production.