scholarly journals A Growing Microcolony can Survive and Support Persistent Propagation of Virulent Phages

2017 ◽  
Author(s):  
Rasmus Skytte Eriksen ◽  
Sine Lo Svenningsen ◽  
Kim Sneppen ◽  
Namiko Mitarai
Keyword(s):  
Defense Mechanisms ◽  
Extracellular Polymeric Substances ◽  
Molecular Mechanisms ◽  
Term Survival ◽  
Virulent Phage ◽  
Spatial Composition ◽  
The Individual ◽  
The Impact ◽  
Spherical Growth

Bacteria form colonies and secrete extracellular polymeric substances that surround the individual cells. These spatial structures are often associated with collaboration and quorum sensing between the bacteria. Here we investigate the mutual protection provided by spherical growth of a monoclonal colony during exposure to phages that proliferate on its surface. As a proof of concept we exposed growing colonies ofEscherichia colito a virulent mutant of phage P1. When the colony consists of less than ~ 50000 members it is eliminated, while larger initial colonies allow long-term survival because the growth of bacteria throughout the spherical colony exceeds the killing of bacteria on the surface. A mathematical model pinpoints how this critical colony size depends on key parameters in the phage infection cycle. Surprisingly, we predict that a higher phage adsorption rate would allow substantially smaller colonies to survive a virulent phage.Significance StatementBacteria are repeatedly exposed to an excess of phages, and carry evidence of this in terms of multiple defense mechanisms encoded in their genome. In addition to molecular mechanisms, bacteria may exploit the defense of spatial refuges. Here we demonstrate how bacteria can limit the impact of a virulent phage attack by growing as a colony which only exposes its surface to phages. We identify a critical size of the initial colony, below which the phages entirely eliminates the colony, and above which the colony continues to grow despite the presence of phages. Our study suggests that coexistence of phages and bacteria is strongly influenced by the spatial composition of microcolonies of susceptible bacteria.

scholarly journals A growing microcolony can survive and support persistent propagation of virulent phages

2017 ◽  
Vol 115 (2) ◽  
pp. 337-342 ◽  
Author(s):  
Rasmus Skytte Eriksen ◽  
Sine L. Svenningsen ◽  
Kim Sneppen ◽  
Namiko Mitarai
Keyword(s):  
Extracellular Polymeric Substances ◽  
Spatial Structures ◽  
Proof Of Concept ◽  
Infection Cycle ◽  
Term Survival ◽  
Resistant Mutants ◽  
The Individual ◽  
Spherical Growth ◽  
Growth Of Bacteria

Bacteria form colonies and secrete extracellular polymeric substances that surround the individual cells. These spatial structures are often associated with collaboration and quorum sensing between the bacteria. Here we investigate the mutual protection provided by spherical growth of a monoclonal colony during exposure to phages that proliferate on its surface. As a proof of concept we exposed growing colonies of Escherichia coli to a virulent mutant of phage P1. When the colony consists of less than ∼50,000 members it is eliminated, while larger initial colonies allow long-term survival of both phage-resistant mutants and, importantly, colonies of mostly phage-sensitive members. A mathematical model predicts that colonies formed solely by phage-sensitive bacteria can survive because the growth of bacteria throughout the colony exceeds the killing of bacteria on the surface and pinpoints how the critical colony size depends on key parameters in the phage infection cycle.

Vicissitudes of Emotions and Political Action During the Greek Crisis

2017 ◽  
Author(s):  
Bettina Davou
Keyword(s):  
Defense Mechanisms ◽  
Political Action ◽  
Traumatic Event ◽  
Well Being ◽  
Norms And Values ◽  
Challenges And Opportunities ◽  
The Individual ◽  
The Impact ◽  
The Brain

Action readiness is considered a central property of emotions in most psychological theories. Emotions are the engine of behavior. They are the motivating, directing, prioritizing function of the brain, and impel to an immediate reaction to challenges and opportunities faced by the organism. Nevertheless, under sociopolitical malaise, emotions do not always lead to action. People leave in societies characterized by particular emotional cultures, climates, and atmospheres that set the background to what emotions are felt under which circumstances. The impact of an emotion depends on how relevant, that is, emotionally significant is the event for the individual; on the implications of the event for the person’s well-being and immediate or long-term goals; on the individual’s capacity to cope with or adjust to the consequences of the event; and on the significance of the event with respect to individual and collective self-concept and to social norms and values. Although emotions trigger action, events with high emotional intensity may mobilize defense mechanisms that distort facts, so that the event may appear distant or not concerning the individual personally. In such cases action is hindered because the meaning of the emotive event, although fully intellectually understood, does not have personal emotional reality. If the defense mechanisms prove inefficient or collapse, the event may be experienced as traumatic, that is, as a shocking occurrence that brings about a rupture in the continuity of existence, numbing of senses and mental faculties, and inability to think about what happened for periods that may last from days to years, although individuals and collectives may appear quite normal in carrying out everyday routines. Interpretative “emotion work” in formal or informal contexts may change emotions from immobilizing to mobilizing, or from destructive to constructive, as the traumatic event is being “worked through” and a cohesive narrative about it develops. But even then, action and in our case, political action, depends on the individual’s available repertoire—political efficacy and resilience—built up from past recoveries and a sense of support from social networks, and hope in assessing the costs and benefits from the harms brought by acting and the harms brought by non-acting.

scholarly journals The influence of hypercapnia and macrofauna on sediment nutrient flux – will ocean acidification affect nutrient exchange?

2009 ◽  
Vol 6 (1) ◽  
pp. 2387-2413 ◽  
Author(s):  
H. L. Wood ◽  
S. Widdicombe ◽  
J. I. Spicer
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Marine Invertebrates ◽  
Nutrient Flux ◽  
Additional Treatment ◽  
Term Survival ◽  
Physicochemical Changes ◽  
Amphiura Filiformis ◽  
The Individual ◽  
The Impact

Abstract. Rising levels of atmospheric carbon dioxide and the concomitant increased uptake of this by the oceans is resulting in hypercapnia-related reduction of ocean pH. Research focussed on the direct effects of these physicochemical changes on marine invertebrates has begun to improve our understanding of impacts at the level of individual physiologies. However, CO2-related impairment of organisms' contribution to ecological or ecosystem processes has barely been addressed. The burrowing ophiuroid Amphiura filiformis, which has a physiology that makes it susceptible to reduced pH, plays a key role in sediment nutrient cycling by mixing and irrigating the sediment, a process known as bioturbation. Here we investigate the role of A. filiformis in modifying nutrient flux rates across the sediment-water boundary and the impact of CO2-related acidification on this process. A 40 day exposure study was conducted under predicted pH scenarios from the years 2100 (pH 7.7) and 2300 (pH 7.3), plus an additional treatment of pH 6.8. This study demonstrated strong relationships between A. filiformis density and cycling of some nutrients; A. filiformis activity increases the sediment uptake of phosphate and the release of nitrite and nitrate. No relationship between A. filiformis density and the flux of ammonium or silicate were observed. Results also indicated that, within the timescale of this experiment, effects at the individual bioturbator level appear not to translate into reduced ecosystem influence. Rather the effect of hypercapnia and lowered pH on bacteria and microphytobenthos may have been of greater significance in understanding the changes to nutrient fluxes seen here. However, long term survival of key bioturbating species is far from assured and changes in both bioturbation and microbial processes could alter key biogeochemical processes in future, more acidic oceans.

scholarly journals Efficacy of Surgery for the Treatment of Gastric Cancer Liver Metastases: A Systematic Review of the Literature and Meta-Analysis of Prognostic Factors

2021 ◽  
Vol 10 (5) ◽  
pp. 1141
Author(s):  
Gianpaolo Marte ◽  
Andrea Tufo ◽  
Francesca Steccanella ◽  
Ester Marra ◽  
Piera Federico ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Systematic Review ◽  
Prognostic Factors ◽  
Liver Metastases ◽  
Meta Analysis ◽  
Multidisciplinary Treatment ◽  
Review Of The Literature ◽  
Term Survival ◽  
The Impact

Background: In the last 10 years, the management of patients with gastric cancer liver metastases (GCLM) has changed from chemotherapy alone, towards a multidisciplinary treatment with liver surgery playing a leading role. The aim of this systematic review and meta-analysis is to assess the efficacy of hepatectomy for GCLM and to analyze the impact of related prognostic factors on long-term outcomes. Methods: The databases PubMed (Medline), EMBASE, and Google Scholar were searched for relevant articles from January 2010 to September 2020. We included prospective and retrospective studies that reported the outcomes after hepatectomy for GCLM. A systematic review of the literature and meta-analysis of prognostic factors was performed. Results: We included 40 studies, including 1573 participants who underwent hepatic resection for GCLM. Post-operative morbidity and 30-day mortality rates were 24.7% and 1.6%, respectively. One-year, 3-years, and 5-years overall survival (OS) were 72%, 37%, and 26%, respectively. The 1-year, 3-years, and 5-years disease-free survival (DFS) were 44%, 24%, and 22%, respectively. Well-moderately differentiated tumors, pT1–2 and pN0–1 adenocarcinoma, R0 resection, the presence of solitary metastasis, unilobar metastases, metachronous metastasis, and chemotherapy were all strongly positively associated to better OS and DFS. Conclusion: In the present study, we demonstrated that hepatectomy for GCLM is feasible and provides benefits in terms of long-term survival. Identification of patient subgroups that could benefit from surgical treatment is mandatory in a multidisciplinary setting.

scholarly journals Corruption, Taxation and the Impact on the Shadow Economy

Economies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 18 ◽  
Author(s):  
Daniel Němec ◽  
Eva Kotlánová ◽  
Igor Kotlán ◽  
Zuzana Machová
Keyword(s):  
Tax Evasion ◽  
Capital Accumulation ◽  
Shadow Economy ◽  
Labour Force ◽  
Destructive Effect ◽  
Eu Member States ◽  
Initial Assumption ◽  
The Individual ◽  
The Impact

While assessing the economic impacts of corruption, the corruption-related transmission channels which influence taxation as such have to be duly considered. Taking the example of the Czech Republic, this article aims to evaluate the impacts corruption has on the size of the shadow economy as well as on the individual sources of long-term economic growth, making use of a transmission channel through which corruption affects the tax burden components. Using the method of an extended DSGE model, it confirms the initial assumption that an increase in perceived corruption supports the shadow economy’s growth, but at the same time, it demonstrates that corruption and especially its perception has a significantly different effect on two key areas—the capital accumulation and the labour force size. It further identifies another sector of the economy representing taxes which are prone to tax evasion while asserting that corruption has a much more destructive effect on this sector of the economy, offering generalized implications for other post-communist EU member states in a similar situation.

scholarly journals Long-Term Tacrolimus Blood Trough Level and Patient Survival in Adult Liver Transplantation

2021 ◽  
Vol 11 (2) ◽  
pp. 90
Author(s):  
Chih-Yang Hsiao ◽  
Ming-Chih Ho ◽  
Cheng-Maw Ho ◽  
Yao-Ming Wu ◽  
Po-Huang Lee ◽  
...  
Keyword(s):  
Patient Survival ◽  
Trough Level ◽  
Medical Center ◽  
Term Survival ◽  
Blood Concentrations ◽  
Long Term Survival ◽  
Tacrolimus Level ◽  
Cox's Model ◽  
The Impact

Tacrolimus is the most widely used immunosuppressant in liver transplant (LT) patients. However, the ideal long-term target level for these patients is unknown. This retrospective study aimed to investigate the impact of tacrolimus blood concentration five years after LT on long-term patient survival outcomes in adult LT recipients. Patients who underwent LT between January 2004 and July 2014 at a tertiary medical center were included in this study (n = 189). The mean tacrolimus blood concentrations of each patient during the fifth year after LT were recorded and the overall survival rate was determined. A multivariate analysis of factors associated with long-term survival was conducted using a Cox’s model. The median follow-up period was 9.63 years, and 144 patients (76.2%) underwent live donor LT. Sixteen patients died within 5 years of LT. In the Cox’s model, patients with a mean tacrolimus blood trough level of 4.6–10.2 ng/mL had significantly better long-term survival than those with a mean tacrolimus blood trough level outside this range (estimated hazard ratio = 4.76; 95% confidence interval: 1.34–16.9, p = 0.016). Therefore, a tacrolimus level no lower than 4.6 ng/mL would be recommended in adult LT patients.

scholarly journals Concomitant tricuspid regurgitation severity and its secondary reduction determine long-term prognosis after transcatheter mitral valve edge-to-edge repair

2021 ◽  
Author(s):  
Martin Geyer ◽  
Karsten Keller ◽  
Kevin Bachmann ◽  
Sonja Born ◽  
Alexander R. Tamm ◽  
...  
Keyword(s):  
Tricuspid Regurgitation ◽  
Survival Data ◽  
Common Finding ◽  
Prognostic Impact ◽  
Term Survival ◽  
Long Term Prognosis ◽  
The Impact ◽  
Symptomatic Benefit

Abstract Background Concomitant tricuspid regurgitation (TR) is a common finding in mitral regurgitation (MR). Transcatheter repair (TMVR) is a favorable treatment option in patients at elevated surgical risk. To date, evidence on long-term prognosis and the prognostic impact of TR after TMVR is limited. Methods Long-term survival data of patients undergoing isolated edge-to-edge repair from June 2010 to March 2018 (combinations with other forms of TMVR or tricuspid valve therapy excluded) were analyzed in a retrospective monocentric study. TR severity was categorized and the impact of TR on survival was analysed. Results Overall, 606 patients [46.5% female, 56.4% functional MR (FMR)] were enrolled in this study. TR at baseline was categorized severe/medium/mild/no or trace in 23.2/34.3/36.3/6.3% of the cases. At 30-day follow-up, improvement of at least one TR-grade was documented in 34.9%. Severe TR at baseline was identified as predictor of 1-year survival [65.2% vs. 77.0%, p = 0.030; HR for death 1.68 (95% CI 1.12–2.54), p = 0.013] and in FMR-patients also regarding long-term prognosis [adjusted HR for long-term mortality 1.57 (95% CI 1.00–2.45), p = 0.049]. Missing post-interventional reduction of TR severity was predictive for poor prognosis, especially in the FMR-subgroup [1-year survival: 92.9% vs. 78.3%, p = 0.025; HR for death at 1-year follow-up 3.31 (95% CI 1.15–9.58), p = 0.027]. While BNP levels decreased in both subgroups, TR reduction was associated with improved symptomatic benefit (NYHA-class-reduction 78.6 vs. 65.9%, p = 0.021). Conclusion In this large study, both, severe TR at baseline as well as missing secondary reduction were predictive for impaired long-term prognosis, especially in patients with FMR etiology. TR reduction was associated with increased symptomatic benefit. Graphic abstract

scholarly journals Clinical and Oncological Value of Preoperative BMI in Gastric Cancer Patients: A Single Center Experience

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Costantino Voglino ◽  
Giulio Di Mare ◽  
Francesco Ferrara ◽  
Lorenzo De Franco ◽  
Franco Roviello ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Patients ◽  
Blood Proteins ◽  
Term Survival ◽  
Long Term Survival ◽  
Single Center Experience ◽  
Group B ◽  
Gastric Cancer Patients ◽  
The Impact

Introduction. The impact of preoperative BMI on surgical outcomes and long-term survival of gastric cancer patients was investigated in various reports with contrasting results.Materials & Methods. A total of 378 patients who underwent a surgical resection for primary gastric cancer between 1994 and 2011 were retrospectively studied. Patients were stratified according to BMI into a normal group (<25, group A), an overweight group (25–30, group B), and an obesity group (≥30, group C). These 3 groups were compared according to clinical-pathological characteristics, surgical treatment, and long-term survival.Results. No significant correlations between BMI and TNM (2010), UICC stage (2010), Lauren’s histological type, surgical results, lymph node dissection, and postoperative morbidity and mortality were observed. Factors related to higher BMI were male genderP<0.05, diabetesP<0.001, and serum blood proteinsP<0.01. A trend to fewer lymph nodes retrieved during gastrectomy with lymphadenectomy in overweight patients (B and C groups) was observed, although not statistically significant. There was no difference in overall survival or disease-specific survival between the three groups.Conclusion. According to our data, BMI should not be considered a significant predictor of postoperative complications or long-term result in gastric cancer patients.

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