Unique organization and regulation of the mrx fimbrial operon in Xenorhabdus nematophila

Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1439-1446 ◽  
Author(s):  
Hongjun He ◽  
Holly A. Snyder ◽  
Steven Forst
Keyword(s):  
Regulatory Protein ◽  
Soil Nematode ◽  
Xenorhabdus Nematophila ◽  
Structural Genes ◽  
Polycistronic Mrna ◽  
The Family ◽  
Low Levels ◽  
A Site ◽  
Mutualistic Association

Xenorhabdus nematophila, a Gram-negative bacterium belonging to the Proteus clade of the family Enterobacteriaceae, forms a mutualistic association with the soil nematode Steinernema carpocapsae. The nematode invades insects and releases Xenorhabdus into the haemolymph, where it participates in insect killing. To begin to understand the role of fimbriae in the unique life cycle of Xenorhabdus, the organization and expression of the mrx fimbrial operon was analysed. The mrx operon contained only five structural genes (mrxACDGH), making it one of the smallest chaperone-usher fimbrial operons studied to date. Unlike the mrp operon of Proteus mirabilis, a site-specific recombinase was not linked to the mrx operon. The intergenic region between the major fimbrial gene (mrxA) and the usher gene (mrxC) lacked a mrpB-like gene, but contained three tandem inverted repeat sequences located downstream of mrxA. A 940 nt mrxA-containing mRNA was the major transcript produced in cells growing on agar, while an mrx polycistronic mRNA was produced at low levels. A canonical σ 70 promoter, identified upstream of mrxA, was not subject to promoter inversion. Fimbriae were not produced in an lrp-mutant strain, suggesting that the leucine-responsive regulatory protein, Lrp, plays a role in the regulation of the mrx operon. These findings show that the genetic organization and regulation of the mrx operon is in several respects distinct from other chaperone-usher fimbrial operons.

scholarly journals The Global Transcription Factor Lrp Controls Virulence Modulation in Xenorhabdus nematophila

2015 ◽  
Vol 197 (18) ◽  
pp. 3015-3025 ◽  
Author(s):  
Elizabeth A. Hussa ◽  
Ángel M. Casanova-Torres ◽  
Heidi Goodrich-Blair
Keyword(s):  
Transcription Factor ◽  
Phenotypic Variation ◽  
Pathogenic Bacteria ◽  
Regulatory Protein ◽  
Inverse Correlation ◽  
Xenorhabdus Nematophila ◽  
Insect Larvae ◽  
Content Type ◽  
Expression Levels

ABSTRACTThe bacteriumXenorhabdus nematophilaengages in phenotypic variation with respect to pathogenicity against insect larvae, yielding both virulent and attenuated subpopulations of cells from an isogenic culture. The global regulatory protein Lrp is necessary forX. nematophilavirulence and immunosuppression in insects, as well as colonization of the mutualistic host nematodeSteinernema carpocapsae, and mediates expression of numerous genes implicated in each of these phenotypes. Given the central role of Lrp inX. nematophilahost associations, as well as its involvement in regulating phenotypic variation pathways in other bacteria, we assessed its function in virulence modulation. We discovered that expression oflrpvaries within an isogenic population, in a manner that correlates with modulation of virulence. Unexpectedly, although Lrp is necessary for optimal virulence and immunosuppression, cells expressing high levels oflrpwere attenuated in these processes relative to those with low to intermediatelrpexpression. Furthermore, fixed expression oflrpat high and low levels resulted in attenuated and normal virulence and immunosuppression, respectively, and eliminated population variability of these phenotypes. These data suggest that fluctuatinglrpexpression levels are sufficient to drive phenotypic variation inX. nematophila.IMPORTANCEMany bacteria use cell-to-cell phenotypic variation, characterized by distinct phenotypic subpopulations within an isogenic population, to cope with environmental change. Pathogenic bacteria utilize this strategy to vary antigen or virulence factor expression. Our work establishes that the global transcription factor Lrp regulates phenotypic variation in the insect pathogenXenorhabdus nematophila, leading to attenuation of virulence and immunosuppression in insect hosts. Unexpectedly, we found an inverse correlation between Lrp expression levels and virulence: high levels of expression of Lrp-dependent putative virulence genes are detrimental for virulence but may have an adaptive advantage in other aspects of the life cycle. Investigation ofX. nematophilaphenotypic variation facilitates dissection of this phenomenon in the context of a naturally occurring symbiosis.

KOMUNIKASI INTERPERSONAL PADA PROSES PENDIDIKAN POLITIK PEMILIH PEMULA

2019 ◽  
Vol 2 (2) ◽  
pp. 188-204
Author(s):  
Affiyah Tri Yuni Sari ◽  
Aissyah Dwi Fitriyani ◽  
Martriana Ponimin Said
Keyword(s):  
Interpersonal Communication ◽  
Political Education ◽  
Unit Of Analysis ◽  
The Family ◽  
Vote Count ◽  
Thousand Islands ◽  
Swing Voters ◽  
Low Levels ◽  
Political Apathy

Political education is one of the important factors in determining the attitude of a voter in the conduct of elections. Beginner voters with low levels of political education tend to have voices that are still floating or called swing-voters. If it is not able to be convinced, the swing-voter can become a golput, but if it can be convinced, the swing-voter can be an additional vote for a candidate or party in the final result of the vote count. The phenomenon of political apathy can be reduced by providing political education to beginner voters, one of the methods is through interpersonal communication. The exchange of values ??that form the basis of interpersonal communication can also occur in the family. This study aims to determine how the role of interpersonal communication in the process of early voter political education. Using the interpretative paradigm and descriptive qualitative research methods, by conducting observations, interviews and documentation studies. The unit of analysis under study is individuals, namely beginner voters at Pramuka Island, Thousand Islands, DKI Jakarta Province. The results of the study show that the role of interpersonal communication in the process of political voter education at Pramuka Island is to conduct discussions, exchange information about politics, and conduct political socialization, this will affect the process of political voter education and political participation in the 2019 Election. Keywords: interpersonal communication; political education; beginner voters; general election

scholarly journals Microbial Population Dynamics in the Hemolymph of Manduca sexta Infected with Xenorhabdus nematophila and the Entomopathogenic Nematode Steinernema carpocapsae

2014 ◽  
Vol 80 (14) ◽  
pp. 4277-4285 ◽  
Author(s):  
Swati Singh ◽  
Jordan M. Reese ◽  
Ángel M. Casanova-Torres ◽  
Heidi Goodrich-Blair ◽  
Steven Forst
Keyword(s):  
Entomopathogenic Nematode ◽  
Natural Infection ◽  
Steinernema Carpocapsae ◽  
Host Immune System ◽  
Xenorhabdus Nematophila ◽  
Content Type ◽  
Host Immune Responses ◽  
Microbial Population Dynamics ◽  
Mutualistic Association

ABSTRACTXenorhabdus nematophilaengages in a mutualistic association with the nematodeSteinernema carpocapsae. The nematode invades and traverses the gut of susceptible insects.X. nematophilais released in the insect blood (hemolymph), where it suppresses host immune responses and functions as a pathogen.X. nematophilaproduces diverse antimicrobials in laboratory cultures. The natural competitors thatX. nematophilaencounters in the hemolymph and the role of antimicrobials in interspecies competition in the host are poorly understood. We show that gut microbes translocate into the hemolymph when the nematode penetrates the insect intestine. During natural infection,Staphylococcus saprophyticuswas initially present and subsequently disappeared from the hemolymph, whileEnterococcus faecalisproliferated.S. saprophyticuswas sensitive toX. nematophilaantibiotics and was eliminated from the hemolymph when coinjected withX. nematophila. In contrast,E. faecaliswas relatively resistant toX. nematophilaantibiotics. When injected by itself,E. faecalispersisted (∼103CFU/ml), but when coinjected withX. nematophila, it proliferated to ∼109CFU/ml. Injection ofE. faecalisinto the insect caused the upregulation of an insect antimicrobial peptide, while the transcript levels were suppressed whenE. faecaliswas coinjected withX. nematophila. Its relative antibiotic resistance together with suppression of the host immune system byX. nematophilamay account for the growth ofE. faecalis. At higher injected levels (106CFU/insect),E. faecaliscould kill insects, suggesting that it may contribute to virulence in anX. nematophilainfection. These findings provide new insights into the competitive events that occur early in infection afterS. carpocapsaeinvades the host hemocoel.

Rescaling social care services: The case of district municipalities in Istanbul

2020 ◽  
pp. 002087281990115
Author(s):  
Elifcan Celebi
Keyword(s):  
Social Care ◽  
Welfare System ◽  
Care Provision ◽  
Care Services ◽  
Policy Domain ◽  
The Social ◽  
The Family ◽  
Low Levels ◽  
Administrative Units

Social care is an immature welfare policy domain in Turkey, with three distinctive characteristics: the central role of the family, limited public expenditure, and low levels of institutionalization and professionalization. However, following local legislative reform in 2004, municipalities have become important actors in social care provision, initiating social care programs for local citizens. This article fills a gap in the existing literature by focusing on the smallest administrative units of the local welfare system: the district municipalities. The article explores and compares the emerging role of district municipalities in social care provision in selected districts of Istanbul to assess, in the context of an immature welfare system, how far they fulfill the principle of universal provision. It finds that while service provision capacity was increased by localization to an extent, the social care provision capacity that district municipalities developed is not sufficient to transform social care policies into one that conforms to the principle of universalism. Due to coordination problems and the wide service area defined by the law, district municipalities ‘pick and choose’ service beneficiaries, instead of ensuring equal access for all local citizens.

scholarly journals Expression, Purification, and Functional Characterization of Atypical Xenocin, Its Immunity Protein, and Their Domains from Xenorhabdus nematophila

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Jitendra Singh Rathore
Keyword(s):  
Protein Complexes ◽  
Functional Characterization ◽  
Single Step ◽  
Soil Nematode ◽  
Xenorhabdus Nematophila ◽  
Toxic Activity ◽  
Immunity Protein ◽  
The Family ◽  
Receptor Domain

Xenorhabdus nematophila, a gram-negative bacterium belonging to the family Enterobacteriaceae is a natural symbiont of a soil nematode from the family Steinernematidae. In this study cloning, expression, and purification of broad range iron regulated multidomain bacteriocin called xenocin from X. nematophila (66 kDa, encoded by xcinA gene) and its multidomain immunity protein (42 kDa, encoded by ximB gene) have been done. xcinA-ximB (N′ terminal 270 bp), translocation, and translocation-receptor domain of xcinA, ximB, and its hemolysin domain were cloned, expressed, and purified by single step Ni-NTA chromatography under native conditions. In the functional characterization, neutralization of xcinA toxicity by immunity domain of ximB gene was determined by endogenous assay. Exogenous toxic assays results showed that only the purified recombinant xenocin-immunity domain (10 kDa) protein complex had toxic activity. Atypical cognate immunity protein (42 kDa) of xenocin was fusion of immunity domain (10 kDa) and hemolysin domain (32 kDa). In silico analysis of immunity protein revealed its similarity with hemolysin and purine NTPase like proteins. Hemolytic activity was not observed in immunity protein or in its various domains; however, full-length immunity protein lacking Walker motif showed ATPase activity. Finally, using circular dichroism performed secondary structural analyses of all the recombinant proteins/protein complexes.

scholarly journals The Family as a Site of Consocial Learning: the Cultural Socialisation of Young People in the Process of Intergenerational Exchange

2021 ◽  
Vol 69 (3) ◽  
pp. 399-415
Author(s):  
Dušan Deák ◽  
Ilze Kačane
Keyword(s):  
Family Environment ◽  
Culture Wars ◽  
Educational Environment ◽  
Cultural Socialization ◽  
Cultural Meanings ◽  
Human Interactions ◽  
Intergenerational Exchange ◽  
The Family ◽  
A Site

Abstract This article explores the family as an educational environment and space for the intergenerational exchange of knowledge. Focusing on the process of cultural socialization as viewed against the currently popular “culture wars” it employs the concept of consociality, which is aimed at grasping the diversity and unpredictability of human interactions, and has been recently rejuvenated by Ulf Hannerz. Investigating the consocial character of learning and intergenerational exchange within the family educational environment, the article takes examples from Slovakia and Latvia and problematizes the relationship between formal and informal learning to demonstrate how it changes knowledge infused with cultural meanings and references. The article argues that this process depends on the consocial conditions in which it is created. It also suggests that viewing the family environment in consocial terms provides us with an opportunity to rethink the role of experiences shared within the family and thereby mitigate ethnic-cum-cultural essentialism.

The New Europeans

Traversing ◽  
2020 ◽  
pp. 110-142
Author(s):  
Susanna Trnka
Keyword(s):  
New Technologies ◽  
First Century ◽  
Social Foundations ◽  
The Social ◽  
The Family ◽  
Self Discovery ◽  
A Site ◽  
Higher Purpose ◽  
European Family

This chapter gives an analysis of reproduction and the role of new technologies in creating and recreating contemporary families. It takes into account both Martin Heidegger's depiction of society as an alienating force and Jan Patocka's emphasis on the social foundations necessary for individuals to engage in “caring” for their “souls.” The chapter reflects on what the role of the family might be in providing possibilities for self-discovery or “self-realization.” Specifically, it examines how to reconcile the rise of new European family lifestyles with a strongly patriarchal culture that emphasizes women as pre-eminently talented in taking care of children and questions what the drawbacks are for men if the family cannot function as a site where they too can find a higher purpose in life. The chapter also considers the pressures and possibilities of creating identities that do not accede to the demands of twenty-first century capitalism.

Domestic entanglements: Family, state, hierarchy, and the Hobbesian state of nature

2018 ◽  
Vol 45 (2) ◽  
pp. 221-238
Author(s):  
Jamie Levin ◽  
Joseph MacKay
Keyword(s):  
International Relations ◽  
Early Modern ◽  
Family Life ◽  
Political Community ◽  
State Of Nature ◽  
Naturally Occurring ◽  
The Family ◽  
A Site ◽  
Family State

AbstractThis article revisits the Hobbesian account of the state of nature and the formation of states, attending to Hobbes’s account of the family. Drawing on feminist readings, we find in theLeviathanan account of the family as a natural political community. We contend specifically that a focus on conceptions of family life in theLeviathan, and in works by Hobbes’s early modern peers, points to the role of the family as a site of socialisation in the prelude to early state formation and in the formation of political hierarchies more generally – including, we suggest, the formation of international hierarchies. These accounts have thus far been missing from International Relations theory. Contra conventional IR theoretic readings of theLeviathan, the Hobbesian state of nature contains the seeds of both anarchy and hierarchy, as overlapping social configurations. While anarchy emerges clearly in the famous condition of ‘war of all against all’, hierarchy also exists in Hobbes’s depiction of family life as a naturally occurring proto-state setting. On the basis of this contemporary feminist analysis of a classic text, we consider implications for the emerging ‘new hierarchy studies’ in IR.

Social Motives Predict Loneliness During a Developmental Transition

2017 ◽  
Vol 76 (4) ◽  
pp. 145-153 ◽  
Author(s):  
Jana Nikitin ◽  
Alexandra M. Freund
Keyword(s):  
Social Relationships ◽  
Well Being ◽  
Social Avoidance ◽  
Social Approach ◽  
Social Motives ◽  
Developmental Transitions ◽  
Avoidance Motivation ◽  
Negative Effect ◽  
Low Levels

Abstract. Establishing new social relationships is important for mastering developmental transitions in young adulthood. In a 2-year longitudinal study with four measurement occasions (T1: n = 245, T2: n = 96, T3: n = 103, T4: n = 85), we investigated the role of social motives in college students’ mastery of the transition of moving out of the parental home, using loneliness as an indicator of poor adjustment to the transition. Students with strong social approach motivation reported stable and low levels of loneliness. In contrast, students with strong social avoidance motivation reported high levels of loneliness. However, this effect dissipated relatively quickly as most of the young adults adapted to the transition over a period of several weeks. The present study also provides evidence for an interaction between social approach and social avoidance motives: Social approach motives buffered the negative effect on social well-being of social avoidance motives. These results illustrate the importance of social approach and social avoidance motives and their interplay during developmental transitions.

Social and Temporal Comparisons as Moderators of Psychological Resources Associations With Wellbeing

2016 ◽  
Vol 37 (2) ◽  
pp. 96-104 ◽  
Author(s):  
Hasida Ben-Zur
Keyword(s):  
Life Satisfaction ◽  
Positive Affect ◽  
Subjective Wellbeing ◽  
Social Comparisons ◽  
Self Esteem ◽  
Psychological Resources ◽  
Low Levels ◽  
Age Range ◽  
General Wellbeing

Abstract. The current study investigated the associations of psychological resources, social comparisons, and temporal comparisons with general wellbeing. The sample included 142 community participants (47.9% men; age range 23–83 years), who compared themselves with others, and with their younger selves, on eight dimensions (e.g., physical health, resilience). They also completed questionnaires assessing psychological resources of mastery and self-esteem, and three components of subjective wellbeing: life satisfaction and negative and positive affect. The main results showed that high levels of psychological resources contributed to wellbeing, with self-enhancing social and temporal comparisons moderating the effects of resources on certain wellbeing components. Specifically, under low levels of mastery or self-esteem self-enhancing social or temporal comparisons were related to either higher life satisfaction or positive affect. The results highlight the role of resources and comparisons in promoting people’s wellbeing, and suggest that self-enhancing comparisons function as cognitive coping mechanisms when psychological resources are low.

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