scholarly journals Cooperation, Competition, and Specialized Metabolism in a Simplified Root Nodule Microbiome

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Bridget L. Hansen ◽  
Rita de Cassia Pessotti ◽  
Monika S. Fischer ◽  
Alyssa Collins ◽  
Laila El-Hifnawi ◽  
...  
Keyword(s):  
Potential Role ◽  
Root Nodule ◽  
Root Nodules ◽  
Imaging Mass Spectrometry ◽  
In Planta ◽  
Content Type ◽  
Specialized Metabolites ◽  
Brevibacillus Brevis

ABSTRACT Microbiomes associated with various plant structures often contain members with the potential to make specialized metabolites, e.g., molecules with antibacterial, antifungal, or siderophore activities. However, when and where microbes associated with plants produce specialized metabolites, and the potential role of these molecules in mediating intramicrobiome interactions, is not well understood. Root nodules of legume plants are organs devoted to hosting symbiotic bacteria that fix atmospheric nitrogen and have recently been shown to harbor a relatively simple accessory microbiome containing members with the ability to produce specialized metabolites in vitro. On the basis of these observations, we sought to develop a model nodule microbiome system for evaluating specialized microbial metabolism in planta. Starting with an inoculum derived from field-grown Medicago sativa nodules, serial passaging through gnotobiotic nodules yielded a simplified accessory community composed of four members: Brevibacillus brevis, Paenibacillus sp., Pantoea agglomerans, and Pseudomonas sp. Some members of this community exhibited clear cooperation in planta, while others were antagonistic and capable of disrupting cooperation between other partners. Using matrix-assisted laser desorption ionization–imaging mass spectrometry, we found that metabolites associated with individual taxa had unique distributions, indicating that some members of the nodule community were spatially segregated. Finally, we identified two families of molecules produced by B. brevis in planta as the antibacterial tyrocidines and a novel set of gramicidin-type molecules, which we term the britacidins. Collectively, these results indicate that in addition to nitrogen fixation, legume root nodules are likely also sites of active antimicrobial production.

scholarly journals In VitroActivity of Imipenem-Relebactam Alone or in Combination with Amikacin or Colistin againstPseudomonas aeruginosa

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Tomefa E. Asempa ◽  
David P. Nicolau ◽  
Joseph L. Kuti
Keyword(s):  
Potential Role ◽  
Multidrug Resistant ◽  
Synergistic Activity ◽  
Content Type ◽  
Class A ◽  
Susceptible Isolate ◽  
Time Kill ◽  
Lactamase Inhibitor

ABSTRACTRelebactam is a novel class A/C β-lactamase inhibitor that restores imipenemin vitroactivity against multidrug-resistant and carbapenem-nonsusceptiblePseudomonas aeruginosa. Time-kill analyses were performed to evaluate the potential role of imipenem-relebactam in combination with amikacin or colistin againstP. aeruginosa. Ten clinicalP. aeruginosaisolates (9 imipenem nonsusceptible) with imipenem-relebactam MICs ranging from 1/4 to 8/4 μg/ml were included. The isolates had varied susceptibilities to imipenem (1 to 32 μg/ml), amikacin (4 to 128 μg/ml), and colistin (0.5 to 1 μg/ml). Duplicate 24-h time-kill studies were conducted using the average steady-state concentrations (Cssavg) observed after the administration of imipenem-relebactam at 500 mg/250 mg every 6 hours (q6h) alone and in combination with theCssavgof 25 mg/kg of body weight/day amikacin and 360 mg/day colistin in humans. Imipenem-relebactam alone resulted in 24-h bacterial densities of −2.93 ± 0.38, −1.67 ± 0.29, +0.38 ± 0.96, and +0.15 ± 0.65 log10CFU/ml at imipenem-relebactam MICs of 1/4, 2/4, 4/4, and 8/4 μg/ml, respectively. No synergy was demonstrated against the single imipenem-susceptible isolate. Against the imipenem-nonsusceptible isolates (n = 9), imipenem-relebactam combined with amikacin resulted in synergy (−2.61 ± 1.50 log10CFU/ml) against all amikacin-susceptible isolates and in two of three amikacin-intermediate (i.e., MIC, 32 μg/ml) isolates (−2.06 ± 0.19 log10CFU/ml). Synergy with amikacin was not observed when the amikacin MIC was >32 μg/ml. Imipenem-relebactam combined with colistin demonstrated synergy in eight out of the nine imipenem-resistant isolates (−3.17 ± 1.00 log10CFU/ml). Against these 10 P. aeruginosaisolates, imipenem-relebactam combined with either amikacin or colistin resulted in synergistic activity against the majority of strains. Further studies evaluating combination therapy with imipenem-relebactam are warranted.

scholarly journals Imaging Mass Spectrometry Reveals Highly Specific Interactions between Actinomycetes To Activate Specialized Metabolic Gene Clusters

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
David A. Hopwood
Keyword(s):  
Mass Spectrometry ◽  
Streptomyces Coelicolor ◽  
Imaging Mass Spectrometry ◽  
Gene Clusters ◽  
Microbial Interactions ◽  
Content Type ◽  
Specialized Metabolites ◽  
Genetic Interventions ◽  
Waking Up

ABSTRACT The genomes of actinomycetes contain numerous gene clusters potentially able to encode the production of many antibiotics and other specialized metabolites that are not expressed during growth under typical laboratory conditions. Undoubtedly, this reflects the soil habitat of these organisms, which is highly complex physically, chemically, and biotically; the majority of the compounds that make up the specialized metabolome are therefore adaptive only under specific conditions. While there have been numerous previous reports of “waking up” the “sleeping” gene clusters, many involving genetic interventions or nutritional challenges, the role of competing microorganisms has been comparatively little studied. Now, Traxler et al. [M. F. Traxler, J. D. Watrous, T. Alexandrov, P. C. Dorrestein, and R. Kolter, mBio 4(4):e00459-13, 2013, doi:10.1128/mBio.00459-13] have used the recently described technique of microscale imaging mass spectrometry to analyze in detail the stimulation of specialized metabolite production by the model actinomycete Streptomyces coelicolor A3(2) by growth in proximity to other actinomycetes. The striking finding from these experiments was that growth of S. coelicolor close to each of the five other actinomycetes studied caused it to produce many specialized metabolites that were not made when it was grown in isolation and that the majority of the compounds were interaction specific, i.e., they occurred only in one of the five pairwise combinations, emphasizing the highly specific nature of the interactions. These observations contribute substantially to the increasing awareness of communication between microorganisms in complex natural communities, as well as auguring well for the discovery of useful specialized metabolites based on microbial interactions.

scholarly journals Specificity of the HIV-1 Protease on Substrates Representing the Cleavage Site in the Proximal Zinc-Finger of HIV-1 Nucleocapsid Protein

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1092
Author(s):  
János András Mótyán ◽  
Márió Miczi ◽  
Stephen Oroszlan ◽  
József Tőzsér
Keyword(s):  
Amino Acid ◽  
Zinc Finger ◽  
Cleavage Site ◽  
Potential Role ◽  
Binding Mode ◽  
Interaction Energies ◽  
Vitro Assay ◽  
Hiv 1

To explore the sequence context-dependent nature of the human immunodeficiency virus type 1 (HIV-1) protease’s specificity and to provide a rationale for viral mutagenesis to study the potential role of the nucleocapsid (NC) processing in HIV-1 replication, synthetic oligopeptide substrates representing the wild-type and modified versions of the proximal cleavage site of HIV-1 NC were assayed as substrates of the HIV-1 protease (PR). The S1′ substrate binding site of HIV-1 PR was studied by an in vitro assay using KIVKCF↓NCGK decapeptides having amino acid substitutions of N17 residue of the cleavage site of the first zinc-finger domain, and in silico calculations were also performed to investigate amino acid preferences of S1′ site. Second site substitutions have also been designed to produce “revertant” substrates and convert a non-hydrolysable sequence (having glycine in place of N17) to a substrate. The specificity constants obtained for peptides containing non-charged P1′ substitutions correlated well with the residue volume, while the correlation with the calculated interaction energies showed the importance of hydrophobicity: interaction energies with polar residues were related to substantially lower specificity constants. Cleavable “revertants” showed one residue shift of cleavage position due to an alternative productive binding mode, and surprisingly, a double cleavage of a substrate was also observed. The results revealed the importance of alternative binding possibilities of substrates into the HIV-1 PR. The introduction of the “revertant” mutations into infectious virus clones may provide further insights into the potential role of NC processing in the early phase of the viral life-cycle.

Strain distribution and in planta production of an extracellular polysaccharide depolymerase from Bradyrhizobium japonicum

1992 ◽  
Vol 38 (8) ◽  
pp. 857-861 ◽  
Author(s):  
Michael F. Dunn ◽  
Arthur L. Karr
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Root Nodules ◽  
Extracellular Polysaccharide ◽  
Extracellular Polysaccharides ◽  
Neutral Sugar ◽  
In Planta ◽  
In Vitro Production ◽  
Polysaccharide Composition ◽  
Vitro Production

Thirty-four strains of Bradyrhizobium japonicum were screened for the in vitro production of an extracellular polysaccharide depolymerase active against the B. japonicum acidic extracellular polysaccharide that contains mannose, glucose, galactose, and 4-O-methylgalactose as neutral sugar components. Over 90% of tested strains producing this type of extracellular polysaccharide also produced the extracellular polysaccharide depolymerase, whereas strains producing a compositionally different extracellular polysaccharide did not. In addition, representatives of species related to B. japonicum by extracellular polysaccharide composition or host range were also phenotypically depolymerase negative. Depolymerase was also present in soybean root nodules formed by B. japonicum strain 2143. In contrast to the cell-associated depolymerase activity found in free-living cells of this strain, most of the depolymerase activity present in nodules is free of the bacteroids. The widespread occurrence of the depolymerase among B. japonicum strains and the spatiotemporal distribution of its activity in planta are consistent with the enzyme playing a role in the removal of surface extracellular polysaccharide from the microorganism during the infection of nodulation process. Key words: Bradyrhizobium japonicum, soybean, extracellular polysaccharides, extracellular polysaccharide depolymerase, bacteroids.

Revitalising Waqf (endowment) lands for agribusiness: potentials of the anchor company models

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Norfaridah Ali Azizan ◽  
Amirul Afif Muhamat ◽  
Sharifah Faigah Syed Alwi ◽  
Husniyati Ali ◽  
Amalia Qistina Casteneda Abdullah
Keyword(s):  
Household Income ◽  
Design Methodology ◽  
Potential Role ◽  
Islamic Law ◽  
Living Condition ◽  
Previous Literature ◽  
Content Type ◽  
Muslim Countries ◽  
The Right

PurposeWaqf (endowment) lands constitute as among the highest types of waqf (endowment) properties in Malaysia; yet it is still unable to reach its maximum potential due to various challenges such as capital, location, legal and administrative issues. Therefore, this study intends to explore these issues by focussing on the two states in Malaysia (Selangor and Perak) that have fertile lands but different management authorities.Design/methodology/approachThere were series of interviews that had been conducted with ten (10) key informants who are experts and practitioners in the areas of Shariah (Islamic law), farming, agribusiness, land management and waqf.FindingsFindings exhibit that constraints and challenges that had been highlighted in the previous literature still exist (although some improvements had been made), but there is emerging theme that the study intends to highlight which is on the needs to secure market for the agribusiness produce and the potential role of anchor company in the agribusiness. It is pertinent that for agribusiness to thrive, selecting the right anchor company that has the capacity to address the challenges is necessary. This study posits two anchor company models (Waqf Trustee-Anchor Company and Waqf Trustee-Anchor Company-Community Farmers) that can be applied for agribusiness on the waqf lands.Research limitations/implicationsThis study is based on the Malaysia's context influenced by specific country's features. Nevertheless, such findings can still be used as reference or benchmark by other endowment trustees in other countries especially for the Muslim countries as well as the non-Muslim countries that have significant Muslim populations.Social implicationsThe suggested models have potentials to improve the living condition of the B40 (below 40% household income) in Malaysia because the models encourage their participation in the agribusiness activities.Originality/valueThis study focusses on the agribusiness, which is rarely being given attention in previous literature in the context of endowment lands. Therefore, this article bridges the literature gap and at the same time attempts to provide suggestion to address the pertinent issue – the underutilised endowment lands.

scholarly journals High Expression of GSDMC Is Associated with Poor Survival in Kidney Clear Cell Cancer

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yun-Qian Cui ◽  
Fei Meng ◽  
Wen-Li Zhan ◽  
Zhou-Tong Dai ◽  
Xinghua Liao
Keyword(s):  
Potential Role ◽  
Clear Cell ◽  
Cell Cancer ◽  
Progression Free Survival ◽  
Renal Clear Cell Carcinoma ◽  
High Expression ◽  
Poor Survival ◽  
Free Survival

This study is aimed at exploring the potential role of GSDMC in kidney renal clear cell carcinoma (KIRC). We analyzed the expression of GSDMC in 33 types of cancers in TCGA database. The results showed that the expression of GSDMC was upregulated in most cancers. We found a significant association between high expression of GSDMC and shortened patient overall survival, progression-free survival, and disease-specific survival. In vitro experiments have shown that the expression of GSDMC was significantly elevated in KIRC cell lines. Moreover, decreased expression of GSDMC was significantly associated with decreased cell proliferation. In summary, we believe that this study provides valuable data supporting future clinical treatment.

scholarly journals Activity of the Pore-Forming Virulence Factor Listeriolysin O Is Reversibly Inhibited by Naturally Occurring S-Glutathionylation

2017 ◽  
Vol 85 (4) ◽  
Author(s):  
Jonathan L. Portman ◽  
Qiongying Huang ◽  
Michelle L. Reniere ◽  
Anthony T. Iavarone ◽  
Daniel A. Portnoy
Keyword(s):  
Protein Function ◽  
Inhibitory Effect ◽  
Cysteine Residue ◽  
Infection Model ◽  
Listeriolysin O ◽  
Content Type ◽  
Pore Forming Proteins

ABSTRACT Cholesterol-dependent cytolysins (CDCs) represent a family of homologous pore-forming proteins secreted by many Gram-positive bacterial pathogens. CDCs mediate membrane binding partly through a conserved C-terminal undecapeptide, which contains a single cysteine residue. While mutational changes to other residues in the undecapeptide typically have severe effects, mutation of the cysteine residue to alanine has minor effects on overall protein function. Thus, the role of this highly conserved reactive cysteine residue remains largely unknown. We report here that the CDC listeriolysin O (LLO), secreted by the facultative intracellular pathogen Listeria monocytogenes, was posttranslationally modified by S-glutathionylation at this conserved cysteine residue and that either endogenously synthesized or exogenously added glutathione was sufficient to form this modification. When recapitulated with purified protein in vitro, this modification completely ablated the activity of LLO, and this inhibitory effect was fully reversible by treatment with reducing agents. A cysteine-to-alanine mutation in LLO rendered the protein completely resistant to inactivation by S-glutathionylation, and a mutant expressing this mutation retained full hemolytic activity. A mutant strain of L. monocytogenes expressing the cysteine-to-alanine variant of LLO was able to infect and replicate within bone marrow-derived macrophages indistinguishably from the wild type in vitro, yet it was attenuated 4- to 6-fold in a competitive murine infection model in vivo. This study suggests that S-glutathionylation may represent a mechanism by which CDC-family proteins are posttranslationally modified and regulated and help explain an evolutionary pressure to retain the highly conserved undecapeptide cysteine.

Marketing to the “middle of the pyramid” in emerging markets using a social network perspective

2014 ◽  
Vol 9 (3) ◽  
pp. 400-423 ◽  
Author(s):  
Tendai Chikweche ◽  
Richard Fletcher
Keyword(s):  
Social Networks ◽  
Middle Class ◽  
Potential Role ◽  
Content Type ◽  
Business Executives ◽  
Advanced Economies ◽  
Sub Saharan ◽  
Corporate Social ◽  
The Impact

Purpose – The purpose of this paper is to expand knowledge about how middle class consumers in Sub-Saharan African markets behave, focusing on the potential role of social networks and the subsequent interactions that take place between these consumers and firms. Design/methodology/approach – A qualitative research method approach comprising personal interviews and observations targeted at consumers and business executives was used covering all four countries. Findings – Key findings include identification of middle of the pyramid (MOP) social networks, their impact on consumer behaviour and nature of consumer and firm interactions that take place as a result of the impact of social networks. Research limitations/implications – The sample size was restricted to 80 consumers in each of the four countries. This might limit generalisability. Practical implications – The study provides managers with insights on the potential role of social networks on marketing to the MOP in Africa. Social implications – The study provides managers with insights on the potential opportunities for corporate social responsibility solutions at the MOP. Originality/value – Research into the middle class in markets other than western advanced economies is a relatively new area of study. The majority of studies on the middle class have focused on North America and Europe ignoring the merging middle class in Africa. Hence, this research expands knowledge by providing basis for exploring new insights on the emerging marketing opportunity within the middle class in Africa.

The relationship between cooperative and competitive behavioral tendencies and trust in coworkers

2020 ◽  
Vol 8 (3) ◽  
pp. 345-360
Author(s):  
Ece Ömüriş ◽  
Ferda Erdem ◽  
Janset Özen Aytemur
Keyword(s):  
Mixed Methods Research ◽  
Potential Role ◽  
Employee Relations ◽  
Hierarchical Regression ◽  
Future Research ◽  
Content Type ◽  
Tourism Sector ◽  
Behavioral Tendencies ◽  
The Relationship

PurposeThis study aims to investigate the relationship between cooperative and competitive behavioral tendencies and trust of coworkers in organizations. Two main hypotheses were developed. The first hypothesis was that cooperativeness and trust in coworkers is positively correlated. The second hypothesis was that competitiveness and trust in coworkers is negatively correlated.Design/methodology/approachThe sample was 442 Turkish tourism sector employees in a labor-intensive industry. Two scales were used to measure trust in coworkers and cooperativeness/competitiveness. A hierarchical regression analysis was performed to understand how individuals' behavioral tendency affects their coworkers' trust in them.FindingsThe findings strongly supported the first hypothesis, in that cooperativeness was positively correlated with trust in coworkers. The second hypothesis was only partially supported because there was no significant relationship between competitiveness and the competency and trustworthiness dimensions of trust. Unselfishness aspect of trust, however, was negatively correlated with competitiveness.Research limitations/implicationsThe main contribution of this study is to show that employee cooperativeness and competitiveness can affect trust in coworker relations. However, the measurement of competitiveness and cooperativeness measurement had limitations due to differences in the culture-specific meanings of cooperation and competition. Future research employing mixed methods research is needed to further explain the content of the two tendencies and the relationship between the concepts.Originality/valueThe literature on trust and employee relations tends to focus more on the issue of trust between managers and subordinates while neglecting the complex and multifaceted structure of trust in employee–employer relations. However, new working forms mean that horizontal relations are increasingly important. Therefore, more research is needed to address the tendencies and structures that affect trust in coworkers. This study draws attention to the potential role of cooperative and competitive behaviors in trust in horizontal employee relations.

scholarly journals Ozone Therapy as Adjuvant for Cancer Treatment: Is Further Research Warranted?

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Bernardino Clavo ◽  
Norberto Santana-Rodríguez ◽  
Pedro Llontop ◽  
Dominga Gutiérrez ◽  
Gerardo Suárez ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Immune Modulation ◽  
Animal Studies ◽  
Potential Role ◽  
Randomized Clinical Trials ◽  
Tumor Hypoxia ◽  
Tumor Resection ◽  
Ozone Therapy

Introduction. This article provides an overview of the potential use of ozone as an adjuvant during cancer treatment.Methods. We summarize the findings of the most relevant publications focused on this goal, and we include our related clinical experience.Results. Over several decades, prestigious journals have publishedin vitrostudies on the capacity of ozone to induce direct damage on tumor cells and, as well, to enhance the effects of radiotherapy and chemotherapy. Indirect effects have been demonstrated in animal models: immune modulation by ozone alone and sensitizing effect of radiotherapy by concurrent ozone administration. The effects of ozone in modifying hemoglobin dissociation curve, 2,3-diphosphoglycerate levels, locoregional blood flow, and tumor hypoxia provide additional support for potential beneficial effects during cancer treatment. Unfortunately, only a few clinical studies are available. Finally, we describe some works and our experience supporting the potential role of local ozone therapy in treating delayed healing after tumor resection, to avoid delays in commencing radiotherapy and chemotherapy.Conclusions.In vitroand animal studies, as well as isolated clinical reports, suggest the potential role of ozone as an adjuvant during radiotherapy and/or chemotherapy. However, further research, such as randomized clinical trials, is required to demonstrate its potential usefulness as an adjuvant therapeutic tool.

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