Navigating the signaling landscape of Ralstonia solanacearum: a study of bacterial two-component systems

Ralstonia solanacearum, the bacterium that causes bacterial wilt, is a destructive phytopathogen that can infect over 450 different plant species. Several agriculturally significant crop plants, including eggplant, tomato, pepper, potato, and ginger, are highly susceptible to this plant disease, which has a global impact on crop quality and yield. There is currently no known preventive method that works well for bacterial wilt. Bacteria use two-component systems (TCSs) to sense their environment constantly and react appropriately. This is achieved by an extracellular sensor kinase (SK) capable of sensing a suitable signal and a cytoplasmic response regulator (RR) which gives a downstream response. Moreover, our investigation revealed that R. solanacearum GMI1000 possesses a substantial count of TCSs, specifically comprising 36 RRs and 27 SKs. While TCSs are known targets for various human pathogenic bacteria, such as Salmonella, the role of TCSs in R. solanacearum remains largely unexplored in this context. Notably, numerous inhibitors targeting TCSs have been identified, including GHL (Gyrase, Hsp, and MutL) compounds, Walk inhibitors, and anti-TCS medications like Radicicol. Consequently, the investigation into the involvement of TCSs in virulence and pathogenesis has gained traction; however, further research is imperative to ascertain whether TCSs could potentially supplant conventional anti-wilt therapies. This review delves into the prospective utilization of TCSs as an alternative anti-wilt therapy, focusing on the lethal phytopathogen R. solanacearum.

Unravelling the genomic secrets of bacterial fish pathogens: a roadmap to aquaculture sustainability

In the field of aquaculture, bacterial pathogens pose significant challenges to fish health and production. Advancements in genomic technologies have revolutionized our understanding of bacterial fish pathogens and their interactions with their host species. This review explores the application of genomic approaches in the identification, classification, and characterization of bacterial fish pathogens. Through an extensive analysis of the literature, we have compiled valuable data on 79 bacterial fish pathogens spanning 13 different phyla, encompassing their whole genome sequences. By leveraging high-throughput sequencing techniques, researchers have gained valuable insights into the genomic makeup of these pathogens, enabling a deeper understanding of their virulence factors and mechanisms of host interaction. Furthermore, genomic approaches have facilitated the discovery of potential vaccine and drug targets, opening up new avenues for the development of effective interventions against fish pathogens. Additionally, the utilization of genomics in fish disease resistance and control in aquaculture has shown promising results, enabling the identification of genetic markers associated with disease resistance traits. This review highlights the significant contributions of genomics to the field of fish pathogen research and underscores its potential for improving disease management strategies and enhancing the sustainability of aquaculture practices.

Computational exploration of the genomic assignments, molecular structure, and dynamics of the ccdABXn2 toxin-antitoxin homolog with its bacterial target, the DNA gyrase, in the entomopathogen Xenorhabdus nematophila

Toxin-antitoxin (TA) modules, initially discovered on bacterial plasmids and subsequently identified within chromosomal contexts, hold a pivotal role in the realm of bacterial physiology. Among these, the pioneering TA system, ccd (Control of Cell Death), primarily localized on the F-plasmid, is known for its orchestration of plasmid replication with cellular division. Nonetheless, the precise functions of such systems within bacterial chromosomal settings remain a compelling subject that demands deeper investigation. To bridge this knowledge gap, our study focuses on exploring ccdABXn2, a chromosomally encoded TA module originating from the entomopathogenic bacterium Xenorhabdus nematophila. We meticulously delved into the system's genomic assignments, structural attributes, and functional interplay. Our findings uncovered intriguing patterns-CcdB toxin homologs exhibited higher conservation levels compared to their CcdA antitoxin counterparts. Moreover, we constructed secondary as well as tertiary models for both the CcdB toxin and CcdA antitoxin using threading techniques and subsequently validated their structural integrity. Our exploration extended to the identification of key interactions, including the peptide interaction with gyrase for the CcdB homolog and CcdB toxin interactions for the CcdA homolog, highlighting the intricate TA interaction network. Through docking and simulation analyses, we unequivocally demonstrated the inhibition of replication via binding the CcdB toxin to its target, DNA gyrase. These insights provide valuable knowledge about the metabolic and physiological roles of the chromosomally encoded ccdABXn2 TA module within the context of X. nematophila, significantly enhancing our comprehension of its functional significance within the intricate ecosystem of the bacterial host.Communicated by Ramaswamy H. Sarma.

Multi-omics analysis identifies potential microbial and metabolite diagnostic biomarkers of bacterial vaginosis

BACKGROUND

Bacterial vaginosis (BV) is a common clinical manifestation of a perturbed vaginal ecology associated with adverse sexual and reproductive health outcomes if left untreated. The existing diagnostic modalities are either cumbersome or require skilled expertise, warranting alternate tests. Application of machine-learning tools to heterogeneous and high-dimensional multi-omics datasets finds promising potential in data integration and may aid biomarker discovery.

OBJECTIVES

The present study aimed to evaluate the potential of the microbiome and metabolome-derived biomarkers in BV diagnosis. Interpretable machine-learning algorithms were used to evaluate the utility of an integrated-omics-derived classification model.

METHODS

Vaginal samples obtained from reproductive-age group women with (n = 40) and without BV (n = 40) were subjected to 16S rRNA amplicon sequencing and LC-MS-based metabolomics. The vaginal microbiome and metabolome were characterized, and machine-learning analysis was performed to build a classification model using biomarkers with the highest diagnostic accuracy.

RESULTS

Microbiome-based diagnostic model exhibited a ROC-AUC (10-fold CV) of 0.84 ± 0.21 and accuracy of 0.79 ± 0.18, and important features were Aerococcus spp., Mycoplasma hominis, Sneathia spp., Lactobacillus spp., Prevotella spp., Gardnerella spp. and Fannyhessea vaginae. The metabolome-derived model displayed superior performance with a ROC-AUC of 0.97 ± 0.07 and an accuracy of 0.92 ± 0.08. Beta-leucine, methylimidazole acetaldehyde, dimethylethanolamine, L-arginine and beta cortol were among key predictive metabolites for BV. A predictive model combining both microbial and metabolite features exhibited a high ROC-AUC of 0.97 ± 0.07 and accuracy of 0.94 ± 0.08 with diagnostic performance only slightly superior to the metabolite-based model.

CONCLUSION

Application of machine-learning tools to multi-omics datasets aid biomarker discovery with high predictive performance. Metabolome-derived classification models were observed to have superior diagnostic performance in predicting BV than microbiome-based biomarkers.

Combined In Silico and In Vitro Study to Reveal the Structural Insights and Nucleotide-Binding Ability of the Transcriptional Regulator PehR from the Phytopathogen Ralstonia solanacearum

The transcriptional regulator PehR regulates the synthesis of the extracellular plant cell wall-degrading enzyme polygalacturonase, which is essential in the bacterial wilt of plants caused by one of the most devastating plant phytopathogens, Ralstonia solanacearum. The bacterium has a wide global distribution infecting many different plant species, resulting in massive agricultural and economic losses. Because the PehR molecular structure has not yet been determined and the structural consequences of PehR on ligand binding have not been thoroughly investigated, we have used an in silico approach combined with in vitro experiments for the first time to characterize the PehR regulator from a local isolate (Tezpur, Assam, India) of the phytopathogenic bacterium R. solanacearum F1C1. In this study, an in silico approach was employed to model the 3D structure of the PehR regulator, followed by the binding analysis of different ligands against this regulatory protein. Molecular docking studies suggest that ATP has the highest binding affinity for the PehR regulator. By using molecular dynamics (MD) simulation analysis, involving root-mean-square deviation, root-mean-square fluctuations, hydrogen bonding, radius of gyration, solvent-accessible surface area, and principal component analysis, it was possible to confirm the sudden conformational changes of the PehR regulator caused by the presence of ATP. We used an in vitro approach to further validate the formation of the PehR-ATP complex. In this approach, recombinant DNA technology was used to clone, express, and purify the gene encoding the PehR regulator from R. solanacearum F1C1. Purified PehR was used in ATP-binding experiments using fluorescence spectroscopy and Fourier transform infrared spectroscopy, the outcomes of which showed a potent binding to ATP. The putative PehR-ATP-binding analysis revealed the importance of the amino acids Lys190, Glu191, Arg192, Arg375, and Asp378 for the ATP-binding process, but further study is required to confirm this. It will be simpler to comprehend the catalytic mechanisms of a crucial PehR regulator process in R. solanacearum with the aid of the ATP-binding process hints provided by these structural biology applications.

Genomic assortment and interactive insights of the chromosomal encoded control of cell death (ccd) toxin-antitoxin (TA) module in Xenorhabdus nematophila

In the present circumstances, toxin-antitoxin (TA) modules have a great consideration due to their elusive role in bacterial physiology. TA modules consist of a toxic part and a counteracting antitoxin part and these are abundant genetic loci harbored on bacterial plasmids and chromosomes. The control of cell death (ccd) TA locus was the first identified TA module and its unitary function (such as plasmid maintenance) has been described, however, the function of its chromosomal counterparts is still ambiguous. Here, we are exploring the genomic assortment, structural and functional association of chromosomally encoded ccdAB TA homolog (ccdABXn1) in the genome of an entomopathogenic bacterium Xenorhabdus nematophila. This bacterium is a symbiotic model with the nematode Steinernema carpocapsae that infects and kills the host insect. By genomic assortment analysis, our observations suggested that CcdA antitoxin homologs are not more closely related than CcdB toxin homologs. Further results suggest that the ccdABXn1 TA homolog has sulphonamide (such as 4C6, for CcdA homolog) and peptide (such as gyrase, for CcdB homolog) ligand partners with a typical TA interaction network that may affect essential cellular metabolism of the X. nematophila. Collectively, our results improve the knowledge and conception of the metabolic interactive role of ccdAB TA homologs in X. nematophila physiology.Communicated by Ramaswamy H. Sarma.

Microliter spotting and micro-colony observation: A rapid and simple approach for counting bacterial colony forming units

For enumerating viable bacteria, traditional dilution plating to count colony forming units (CFUs) has always been the preferred method in microbiology owing to its simplicity, albeit being laborious and time-consuming. Similar CFU counts can be obtained by quantifying growing micro-colonies in conjunction with the benefits of a microscope. Here, we employed a simple method of five to ten microliter spotting of a diluted bacterial culture multiple times on a single Petri dish followed by determining CFU by counting micro-colonies using a phase-contrast microscope. In this method, the CFU of an Escherichia coli culture can be estimated within a four-hour period after spotting. Further, within a ten-hour period after spotting, CFU in a culture of Ralstonia solanacearum, a bacterium with a generation time of around 2 h, can be estimated. The CFU number determined by micro-colonies observed for 10⁶-fold dilutions or lower is similar to that obtained by the dilution plating method for 10⁷-fold dilutions or lower. Micro-colony numbers observed in the early hours of growth (2 h in case of E. coli and 8 h in case of R. solanacearum) were found to remain consistent at later hours (4 h in case of E. coli and 10 h in case of R. solanacearum), where the visibility of the colonies was better due to a noticeable increase in the size of the colonies. This suggested that micro-colonies observed in the early hours indeed represent the bacterial number in the culture. Practical applications to this counting method were employed in studying the rifampicin-resistant mutation rate as well as performing a fluctuation test in E. coli. The spotting method described here to enumerate bacterial CFU results in reduction of labour, time and resources.

A Three-Dimensional Analysis of Morphological Variations in Maxillary Second Molar in a North Indian Population Using Cone-Beam Computed Tomography

Background: Cone beam computed tomography (CBCT) has evolved in the field of endodontics and has helped to diagnose and treat the case very easily and accurately. The researchers set out to pinpoint the exact placement of the roots and canals in the maxillary second molars of North Indians by analyzing CBCT pictures.

Methods: In this study, in vivo CBCT was used to examine the maxillary second molars (n = 70) in detail. Both the number and configuration of root canals may be determined using Vertucci's categorization.

Results: Most people had three roots in their second molars (85.7%). Most maxillary second molars that had three roots looked like they had three separate roots (81.7%). In the roots of 85.7% of maxillary second molars, one canal was found in the mesiobuccal roots, and 14.2% had an MB2 canal. All of the canals in the palatal, distobuccal root, and MB1 root were Type I. The Type II canal configuration was found in 11.7% of MB2 canals. Type IV canals were found in 5% of the MB2 canals. The number of maxillary second molars with MB2 was found to be the same for both men and women (P =0.11). The number of MB2 cases did not depend on where the teeth were or how old the person was (P=0.08 and 0.06, respectively). The fact that both second molars appeared at the same time was important (P<0.001).

Conclusions: We report the occurrence of unusual morphologic abnormalities that affect only one root and have only been described in case reports. CBCT scans can help doctors better understand root canal anatomy and potentially enhancing endodontic management outcomes.

Effects of gain-loss-framed messages on virtual reality intervened fitness exercise

Purpose

Technology for fitness provides users with numerous features that aid the achievement of intended fitness/health goals such as checking consumption habits and adherence to exercise. Based upon the concepts of self-efficacy and prospect theories, this study aims to inspect the influence of messages frame on behavioral usage of virtual reality (VR) technology intervened fitness exercise.

Design/methodology/approach

By usage of a laboratory-based experiment commissioning certain fitness exercises, this study is conducted on 150 respondents. An assessment is conducted on the efficiency of gain appeal mechanism (exercise performance feedback) toward the usage of VR intervened fitness exercise and measured surge in exercise self-efficacy (ESE), playfulness (PL) and outcome expectations.

Findings

The results show that gain-appealed/framed messages prove advantageous over loss-appealed/framed in performing VR intervened exercises. A bootstrapped (method) mediation analysis confirms higher positive effects of gain-framed messages upon intentions to use VR intervened fitness exercise. VR intervened fitness exercise was strongly and positively mediated by ESE, PL and outcome expectations.

Practical implications

This study is of help to researchers and marketers trying to understand the role played by gain- and loss-framed messages on VR technology enabled fitness exercises.

Originality/value

This study helps VR and fitness technology developers and marketers understand the effectiveness of persuasive performance messages toward VR fitness exercise technology adoption amalgamating message intervention with better technology usage.

Bacterial toxin-antitoxin modules: classification, functions, and association with persistence

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Ubiquitously present bacterial Toxin-Antitoxin (TA) modules consist of stable toxin associated with labile antitoxin.

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Classification of TAs modules based on inhibition of toxin through antitoxin in 8 different classes.

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Variety of specific toxin targets and the abundance of TA modules in various deadly pathogens.

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Specific role of TAs modules in conservation of the resistant genes, emergence of persistence & biofilm formation.

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Proposed antibacterial strategies involving TA modules for elimination of multi-drug resistance.

Toxin-antitoxin (TA) modules are ubiquitous gene loci among bacteria and are comprised of a toxin part and its cognate antitoxin part. Under normal physiological conditions, antitoxin counteracts the toxicity of the toxin whereas, during stress conditions, TA modules play a crucial role in bacterial physiology through involvement in the post-segregational killing, abortive infection, biofilms, and persister cell formation. Most of the toxins are proteinaceous that affect translation or DNA replication, although some other intracellular molecular targets have also been described. While antitoxins may be a protein or RNA, that generally neutralizes its cognate toxin by direct interaction or with the help of other signaling elements and thus helps in the TA module regulation. In this review, we have discussed the current state of the multifaceted TA (type I–VIII) modules by highlighting their classification and specific targets. We have also discussed the presence of TA modules in the various pathogens and their role in antibiotic persistence development as well as biofilm formation, by influencing the different cellular processes. In the end, assembling knowledge about ubiquitous TA systems from pathogenic bacteria facilitated us to propose multiple novel antibacterial strategies involving artificial activation of TA modules.

Functional and transcriptional analysis of chromosomal encoded hipBAXn2 type II toxin-antitoxin (TA) module from Xenorhabdus nematophila

Xenorhabdus nematophila is an entomopathogenic bacterium that synthesizes numerous toxins and kills its larval insect host. Apart from such toxins, its genome also has a plethora of toxin-antitoxin (TA) systems. The role of TA systems in bacterial physiology is debatable; however, they are associated with maintaining bacterial genomic stability and their survival under adverse environmental conditions. Here, we explored the functionality and transcriptional regulation of the type II hipBA^Xn2 TA system. This TA system was identified in the genome of X. nematophila ATCC 19061, which consists of the hipA^Xn2 toxin gene encoding 278 amino acid residues and hipB^Xn2 encoding antitoxin of 135 amino acid residues. We showed that overexpression of HipA^Xn2 toxin reduced the growth of Escherichia coli cells in a bacteriostatic manner, and amino-acids G8, H164, N167, and S169 were key residues for this growth reduction. Promoter activity and expression profiling of the hipBA^Xn2 TA system was showed that transcription was induced in both E. coli as well as X. nematophila upon exposure to different stress conditions. Further, we have exhibited the binding features of HipA^Xn2 toxin and HipB^Xn2 antitoxin to their promoter. This study provides evidence for the presence of a functional and well-regulated hipBA^Xn2 TA system in X. nematophila.

Assessing the effects of common topical exposures on skin bacteria associated with atopic dermatitis

Background

While patients and families struggling with atopic dermatitis (AD) have documented concerns for a contributory role of skin care products in AD pathology, nearly all the skin microbiome studies to date have asked participants to avoid topical products (such as soaps or select medications) for the preceding days to weeks prior to sample collection. Thus, given the established role of the microbiome in AD, the interactions between topical exposures, dysbiosis and AD remains underrepresented in the academic literature.

Objectives

To address this knowledge gap, we expanded our previous evaluations to test the toxicological effects of a broader range of common chemicals, AD treatment lotions, creams and ointments using both health- and AD-associated strains of Roseomonas mucosa and Staphylococcus spp.

Methods

Use of in vitro culture techniques and mouse models were deployed to identify chemicals with dysbiotic or pre-biotic potential. A proof-of-concept study was subsequently performed in healthy volunteers to assess global microbiome shifts after exposure to select chemicals using dermatologic patch testing.

Results

Numerous chemicals possessed antibiotic properties, including many not marketed as anti-microbials. Through targeted combination of potentially beneficial chemicals, we identified combinations which promoted the growth of health-associated isolates over disease-associated strains in bacterial culture and enhanced microbe-specific outcomes in an established mouse model of AD; the most promising of which was the combination of citral and colophonium (often sold as lemon myrtle oil and pine tar). Additional studies would likely further optimize the combination of ingredients use. Similar results were seen in the proof-of-concept human studies.

Conclusions

Our results could offer a systematic, multiplex approach to identify which products carry dysbiotic potential and thus may guide formulation of new topicals to benefit patients with AD.

Effect of Change Agent Leadership Style on Successful ERP Implementation and Firm Performance

The study aims to measure Change Agent’s Leadership style on successful ERP Implementation and Organizational Performance. The data was collected through a self-administered questionnaire from 290 employees working in 14 knowledge-based companies in United Arab Emirates with a response rate of 69.04%. The study uses cross sectional research design with snowball sampling method and data were collected using online survey method. Some of the findings include, all the three leadership styles (transformational, transactional, and laissez-faire) significantly contribute to ERP implementation success and in turn impacts Firm Performance. Transformational leadership style of change agent is found to have highest impact on Firm Performance with ERP implementation acting as a partial mediator. Present study opened the doors by linking leadership style with ERP implementation towards multidimensionality of change agent’s reach not being limited to some aspects. Practitioners can use the insights in understanding the impact of change agent’s deployment in organization.

Novel Toxin-antitoxin System Xn-mazEF from Xenorhabdus nematophila: Identification, Characterization and Functional Exploration

BACKGROUND

Xenorhabdus nematophila maintains species-specific mutual interaction with nematodes of Steinernema genus. Type II Toxin Antitoxin (TA) systems, the mazEF TA system controls stress and programmed cell death in bacteria.

OBJECTIVE

This study elucidates the functional characterization of Xn-mazEF, a mazEF homolog in X. nematophila by computational and in vitro approaches.

METHODS

3D- structural models for Xn-MazE toxin and Xn-MazF antitoxin were generated, validated and characterized for protein - RNA interaction analysis. Further biological and cellular functions of Xn-MazF toxin were also predicted. Molecular dynamics simulations of 50ns for Xn- MazF toxin complexed with nucleic acid units (DU, RU, RC, and RU) were performed. The MazF toxin and complete MazEF operon were endogenously expressed and monitored for the killing of Escherichia coli host cells under arabinose induced tightly regulated system.

RESULTS

Upon induction, E. coli expressing toxin showed rapid killing within four hours and attained up to 65% growth inhibition, while the expression of the entire operon did not show significant killing. The observation suggests that the Xn-mazEF TA system control transcriptional regulation in X. nematophila and helps to manage stress or cause toxicity leading to programmed death of cells.

CONCLUSION

The study provides insights into structural and functional features of novel toxin, Xn- MazF and provides an initial inference on control of X. nematophila growth regulated by TA systems.

Comparative Assessment of Revascularization Versus Drug Management in Coronary Artery Disease (CAD) Associated with Left Ventricular Dysfunction (EF < 40%) - A 12 Month Study with FDG PET and SPECT MPI Analyses

AIM OF THE STUDY

Left Ventricular (LV) function and myocardial viability is the key predictor of prognosis after myocardial infarction. Management of ischemic cardiomyopathy (revascularization and or drugs alone) is the objective of this study.

METHODOLOGY

72 patients were assigned to revascularization and medical management group based on the inclusion criteria Follow up was done upto 12 months with advanced imaging techniques (FDG PET and SPECT MPI analyses).

RESULTS

Subjects with significant viable myocardium, revascularization resulted in significant improvement in heart failure symptoms. The mean NYHA functional class improved from 2.9 ± 0.3 to 2.3 ± 0.5(mean ± SD) after 6 months of revascularization (p < 0.01). This improvement in functional class was maintained after 12 months of revascularization (2.0 ± 0.4 (mean ± SD). Subjects on medical management with a baseline NYHA functional class 2.7 ± 0.5, at 6 months of follow, there was no significant change in functional class (2.8 ± 0.3) (p<0.24). However at 12 months follow up functional class had dropped to 3.0 + 0.3, which was significant as compared to baseline (p <0.03).

CONCLUSION

coronary revascularization has a protective effect on patients with ischemic coronary who have viable myocardium and reversible myocardial ischemia as assessed by 18F-FDG PET and SPECT MPI Imaging.

Overview of the rules of the microbial engagement in the gut microbiome: a step towards microbiome therapeutics

Human gut microbiome is a diversified, resilient, immuno-stabilized, metabolically active and physiologically essential component of the human body. Scientific explorations have been made to seek in-depth information about human gut microbiome establishment, microbiome functioning, microbiome succession, factors influencing microbial community dynamics and the role of gut microbiome in health and diseases. Extensive investigations have proposed the microbiome therapeutics as a futuristic medicine for various physiological and metabolic disorders. A comprehensive outlook of microbial colonization, host-microbe interactions, microbial adaptation, commensal selection and immuno-survivability is still required to catalogue the essential genetic and physiological features for the commensal engagement. Evolution of a structured human gut microbiome relies on the microbial flexibility towards genetic, immunological and physiological adaptation in the human gut. Key features for commensalism could be utilized in developing tailor-made microbiome-based therapy to overcome various physiological and metabolic disorders. This review describes the key genetics and physiological traits required for host-microbe interaction and successful commensalism to institute a human gut microbiome.

The hipBAXn operon from Xenorhabdus nematophila functions as a bonafide toxin-antitoxin module

Here, for the first time, we have investigated the hipBA^Xn toxin-antitoxin (TA) module from entomopathogenic bacterium Xenorhabdus nematophila. It is a type II TA module that consists of HipA^Xn toxin and HipB^Xn antitoxin protein and located in the complementary strand of chromosome under XNC1_operon 0810 locus tag. For functional analysis, hipA^Xn toxin, hipB^Xn antitoxin, and an operon having both genes were cloned in pBAD/His C vector and transformed in Escherichia coli cells. The expression profiles and endogenous toxicity assay were performed in these cells. To determine the active amino acid residues responsible for the toxicity of HipA^Xn toxin, site-directed mutagenesis (SDM) was performed. SDM results showed that amino acid residues S149, D306, and D329 in HipA^Xn toxin protein were significantly essential for its toxicity. For transcriptional analysis, the 157 bp upstream region of the hipBA^Xn TA module was identified as a promoter with bioinformatics tools. Further, the LacZ reporter construct with promoter region was prepared and LacZ assays as well as reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed under different stress conditions. Electrophoretic mobility shift assay (EMSA) was also performed with recombinant HipA^Xn toxin, HipB^Xn antitoxin protein, and 157 bp promoter region. Results showed that the hipBA^Xn TA module is a well-regulated system in which the upregulation of gene expression was also found compulsive in different SOS conditions. KEY POINTS: •Functional characterization of hipBA ^Xn TA module from Xenorhabdus nematophila. •hipBA ^Xn TA module is a functional type II TA module. •Transcriptional characterization of hipBA ^Xn TA module. •hipBA ^Xn TA module is a well regulated TA module. Graphical abstract.

Satisfaction from romantic relationship and social media usage

Purpose

The purpose of this paper is to examine the influence of satisfaction from romantic relationships on social media usage, with computer-mediated communication (CMC) motives and self-disclosure dimensions acting as mediators of the relationship.

Design/methodology/approach

The data were collected from 420 individuals active on social media. Data were analysed with confirmatory factor analysis, Pearson correlation, hierarchical multiple regression and mediation analysis based on Baron and Kenny’s (1986) conditions.

Findings

The result from a cross-sectional survey of 420 individuals reveals how relationship satisfaction leads to the use of six social media channels directly and indirectly through five dimensions of CMC motives and four dimensions of self-disclosure. Out of 54 possible mediations, 17 were found to be significant.

Originality/value

The present study fulfils the need to identify how satisfaction in a romantic relationship impacts self-disclosure and social media selection and usage.

Late onset systemic sclerosis with seronegativity: a rare presentation of an uncommon disease

Systemic sclerosis (SSc) is an uncommon connective tissue disorder characterized by multisystem involvement with fibrosis of skin and internal organs. Antibody formation is one of the hallmarks of SSc. Antinuclear antibodies (ANA) are positive in 97% of patients with SSc. We report a rare case where the patient was negative for ANA, Anti-topoisomerase I, Anti-centromere and Anti-RNA polymerase III antibodies.

Demographic variables as moderators between QWL and OCB

Purpose

The purpose of this paper is to examine the impact of quality of work life (QWL) on organizational citizenship behaviour (OCB) of employees. Also, the paper examines the role of demographic variables, i.e. gender, position and type of organization as moderators of relationship between QWL and OCB.

Design/methodology/approach

A survey with sample of 375 was used in this study. PROCESS tool by Hayes (2013) was used to analyze the relation between QWL, OCB and demographic variables.

Findings

QWL was found to positively influence OCB. Gender and type of organization were found to moderate the relationship, whereas position failed to moderate the relation significantly.

Practical implications

The study reinforced the significance of QWL practices by organizations to improve extra-role behaviours of employees. Also, importance of considering gender and the industry you are in is emphasized in using and designing the QWL programme for employees.

Originality/value

While many antecedents have been studied in relation to OCB, QWL is rarely discussed. The paper attempts to reemphasize QWL’s importance in doing so in light of demographic variables as moderators.

Transformational leadership and knowledge sharing behavior in freelancers

Purpose

The purpose of this study is to explore the relationship between transformational leadership and knowledge sharing behavior in freelancers. Also, the study focuses upon mediation of the relationship by employee engagement and moderation by social support.

Design/methodology/approach

Confirmatory factor analysis was used to find validity and reliability of the model under study. To study the relation between variables, the Pearson correlation was used. Further, the PROCESS macro of Hayes (2013) was used to test mediation and moderated mediation.

Findings

Transformational leadership influenced knowledge collecting and knowledge donating behavior in freelancers. The relation was mediated by employee engagement. Social support was found to moderate the mediated path by employee engagement between transformational leadership and knowledge collecting behavior. A similar result was found for knowledge donating behavior as a dependent variable.

Research limitations/implications

The model under study can be tested in other contexts with extended data.

Practical implications

The study asserts importance on freelancers in knowledge sharing in client organizations; leaders should take a transformational role to create a culture of free flow of knowledge and information between various types of employees.

Originality/value

This study is the first to research how transformational leadership, through engagement, motivates freelancers in engaging in knowledge collecting and knowledge donating. The importance of social support is also noted.

A Review on BiOX (X= Cl, Br and I) Nano-/Microstructures for Their Photocatalytic Applications

In the recent past, bismuth oxyhalides (BiOX) have been widely used for the photocatalytic degradation of the organic pollutants and other environmental remediation because of their higher stability, economic viability, nontoxicity and effective charge separation. We begin with the review of the different approaches adopted so far for BiOX (X = Cl, Br, and I) synthesis and a study of their photocatalytic performances under UV and visible light towards the various organic as well as inorganic pollutants. Later on, a study on further enhancement of the efficiency of BiOX under UV and visible light irradiation using recent advancements would be presented. The new approaches involve controlled morphology by forming composite and hybrid materials with other semiconductors and also doping with other metals and nonmetals that would undoubtedly be beneficial in the interfacial charge transfer and efficient inhibition of the photo-generated species. Herein, we would also exploit the recent developments in the research strategies for enhancing photocatalytic activity of BiOX.

Plant leaf extracts as photocatalytic activity tailoring agents for BiOCl towards environmental remediation

The inducement of plant leaf extracts for the synthesis of various nanostructures has intrigued researchers across the earth to explore the mechanisms of biologically active compounds present in the plants. Herein, a green modified hydrolysis route has been employed for the synthesis of bismuth oxychloride i.e. BiOCl-N, BiOCl-T and BiOCl-A using plant extracts of Azadirachta indica (Neem), Ocimum sanctum (Tulsi), and Saraca indica (Ashoka), and; simultaneously, without plant extract (BiOCl-C), respectively. The as-prepared samples were examined by several microscopic and spectroscopic techniques which revealed that the biosynthesized BiOCl attained certain favorable features such as hierarchical nano-flower morphology, higher porosity, higher specific surface area and narrower band gap compared to BiOCl-C. The degradation of methyl orange (MO) and bisphenol A (BPA) using biosynthesized BiOCl were improved by 21.5% within 90 min and 18.2% within 600 min under visible light irradiation, respectively. The photocurrent response, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) studies indicated the effective inhibition of the electron-hole pair recombination and enhanced photocatalytic activity of the biosynthesized BiOCl.

The impact of transformational leadership on employees’ acceptance to change

Purpose

The purpose of this study is to empirically examine the association between transformational leadership and employee acceptance to change while establishing the mediating effects of innovative behaviour and the moderating effect of the use of information technology (IT) on this association.

Design/methodology/approach

In total, 378 employees of ten banks from Uttarakhand, India, participated in a questionnaire-based survey. The proposed hypotheses and the proposed conceptual model were tested using macro process (Hayes, 2013).

Findings

The results indicated that there exists a positive association between transformational leadership and employee acceptance to change. Furthermore, it was found that this association was mediated by employee innovative behaviour and moderated by the use of IT.

Practical implications

The findings of this study will help managers to comprehend the significance of the innovative behaviour of employees in moulding their acceptance towards change. This paper should encourage bank managers to perceive the significance of the working practice and the infusion of IT. Furthermore, this study accentuates the significance of an effective leadership style, i.e. transformational leadership, as an essential phenomenon to positively impinge on employee acceptance to change in a service-oriented industry, namely banking.

Originality/value

The present study enriches the extant research on transformational leadership and employee acceptance to change by demonstrating the use of IT and innovative behaviour as vital and the important factors that influence the level of persuasion that transformational leadership has on employee acceptance to change.

Impact of Spirituality/Religiousness on Cyber Bullying and Victimization in University Students: Mediating Effect of Emotional Intelligence

The aim of the study was to explore the relationship between spirituality/religiousness with cyber bullying and victimization amongst Indian University students and whether emotional intelligence mediates the relationship. Data were collected from 490 University students studying in undergraduate and postgraduate courses across India. IBM AMOS was used to find reliability and validity of instruments and PROCESS macro for IBM SPSS by Preacher and Hayes (Behav Res Methods 36(4): 717-731, 2004) was used for conducting mediation analyses. Both spiritual and existential well-being were found negatively related with cyber bullying and victimization. As far as mediation goes, the negative relationships between spiritual and existential well-being with that of cyber bullying and victimization were significantly mediated by Appraisal of Self-Emotions, Appraisal of Other's Emotions and Regulation and control of Emotions dimensions of emotional intelligence. Implication and future directions are also discussed.

Predicting online repurchase intentions with e-satisfaction as mediator: a study on Gen Y

Purpose

Shopping online is a fast-growing phenomenon. A look into the rapid exponential growth of the primary players in this sector shows huge market potential for e-commerce. Given the convenience of internet shopping, e-commerce is seen as an emerging trend among consumers, specifically the younger generation (Gen Y). The popularity of e-commerce and online shopping has captured the attention of e-retailers, encouraging researchers to focus on this area. This paper aims to examine the relationship between online repurchase intention and other variables such as security, privacy concerns, trust and ease of use (EOU), mediated by e-satisfaction.

Design/methodology/approach

A self-administered survey method is used, and students aged between 20 and 35 years at universities in northern India are selected as subjects. To test the hypotheses of this study, an online questionnaire is distributed to participants, with 309 legitimate responses received. The data are analyzed using SPSS version 20.0 and AMOS version 20.0. Structural equation modeling is used to examine the model and to test the hypotheses.

Findings

The results of this study show that security, privacy concerns, trust and EOU have a positive significant relationship with repurchase intention. The findings also reveal that e-satisfaction has a full mediation effect between security and repurchase intention and also between trust and repurchase intention. In addition, a partial mediation effect of e-satisfaction is noted between EOU and repurchase intention and between privacy concerns and repurchase intention.

Practical implications

The results show that security, trust, EOU and privacy concerns are the factors that have most impact on consumer purchasing behavior. In terms of the repurchase intention of Gen Y consumers, what is needed are strong security features, an easy-to-use interface, a trusted privacy policy and the creation of trust. Furthermore, it may be beneficial to observe e-satisfaction as a mediator when identifying potential problems; online satisfaction is important for the group in this study, and the results show that it impacts on the relation between repurchase intention and other factors.

Social implications

In terms of the repurchase intention of Gen Y consumers, what is needed are strong security features, an easy-to-use interface, a trusted privacy policy and the creation of trust. Furthermore, it may be beneficial to observe e-satisfaction as a mediator when identifying potential problems; online satisfaction is important for the group in this study, and the results show that it impacts on the relation between repurchase intention and other factors.

Originality/value

This research determines the impact of security, privacy concerns, EOU and trust on the online repurchasing behavior of Gen Y in India. The mediation effect of e-satisfaction is also determined.

Facile Green Synthesis of BiOBr Nanostructures with Superior Visible-Light-Driven Photocatalytic Activity

Novel green bismuth oxybromide (BiOBr-G) nanoflowers were successfully synthesized via facile hydrolysis route using an Azadirachta indica (Neem plant) leaf extract and concurrently, without the leaf extract (BiOBr-C). The Azadirachta indica leaf extract was employed as a sensitizer and stabilizer for BiOBr-G, which significantly expanded the optical window and boosted the formation of photogenerated charge carriers and transfer over the BiOBr-G surface. The photocatalytic performance of both samples was investigated for the degradation of methyl orange (MO) and phenol (Ph) under the irradiation of visible light. The leaf extract mediated BiOBr-G photocatalyst displayed significantly higher photocatalytic activity when compared to BiOBr-C for the degradation of both pollutants. The degradation rate of MO and Ph by BiOBr-G was found to be nearly 23% and 16% more when compared to BiOBr-C under visible light irradiation, respectively. The substantial increase in the photocatalytic performance of BiOBr-G was ascribed to the multiple synergistic effects between the efficient solar energy harvesting, narrower band gap, high specific surface area, porosity, and effective charge separation. Furthermore, BiOBr-G displayed high stability for five cycles of photocatalytic activity, which endows its practical application as a green photocatalyst in the long run.

Osteopontin regulates dentin and alveolar bone development and mineralization

The periodontal complex is essential for tooth attachment and function and includes the mineralized tissues, cementum and alveolar bone, separated by the unmineralized periodontal ligament (PDL). To gain insights into factors regulating cementum-PDL and bone-PDL borders and protecting against ectopic calcification within the PDL, we employed a proteomic approach to analyze PDL tissue from progressive ankylosis knock-out (Ank^-/-) mice, featuring reduced PP_i, rapid cementogenesis, and excessive acellular cementum. Using this approach, we identified the matrix protein osteopontin (Spp1/OPN) as an elevated factor of interest in Ank^-/- mouse molar PDL. We studied the role of OPN in dental and periodontal development and function. During tooth development in wild-type (WT) mice, Spp1 mRNA was transiently expressed by cementoblasts and strongly by alveolar bone osteoblasts. Developmental analysis from 14 to 240days postnatal (dpn) indicated normal histological structures in Spp1^-/- comparable to WT control mice. Microcomputed tomography (micro-CT) analysis at 30 and 90dpn revealed significantly increased volumes and tissue mineral densities of Spp1^-/- mouse dentin and alveolar bone, while pulp and PDL volumes were decreased and tissue densities were increased. However, acellular cementum growth was unaltered in Spp1^-/- mice. Quantitative PCR of periodontal-derived mRNA failed to identify potential local compensators influencing cementum in Spp1^-/- vs. WT mice at 26dpn. We genetically deleted Spp1 on the Ank^-/- mouse background to determine whether increased Spp1/OPN was regulating periodontal tissues when the PDL space is challenged by hypercementosis in Ank^-/- mice. Ank^-/-; Spp1^-/- double deficient mice did not exhibit greater hypercementosis than that in Ank^-/- mice. Based on these data, we conclude that OPN has a non-redundant role regulating formation and mineralization of dentin and bone, influences tissue properties of PDL and pulp, but does not control acellular cementum apposition. These findings may inform therapies targeted at controlling soft tissue calcification.

Humoral and T cell-mediated immune response against trichomoniasis

Trichomonas vaginalis (T. vaginalis) infection leads to the synthesis of specific antibodies in the serum and local secretions. The profile of T. vaginalis-specific antibodies and T cell-mediated immune responses may influence the outcome of infection, towards parasite elimination, persistence or pathological reactions. Studies have indicated that Th1-, Th17- and Th22 cell-related cytokines may be protective or pathogenic, whereas Th2- and Treg cell-related cytokines can exert anti-inflammatory effects during T. vaginalis infection. A number of T. vaginalis-related components such as lipophosphoglycan (TvLPG), α-actinin, migration inhibitory factor (TvMIF), pyruvate:ferredoxin oxidoreductase (PFO), legumain-1 (TvLEGU-1), adhesins and cysteine proteases lead to the induction of specific antibodies. T. vaginalis has acquired several strategies to evade the humoral immune responses such as degradation of immunoglobulins by cysteine proteases, antigenic variation and killing of antibody-producing B cells. The characterization of the T. vaginalis-specific antibodies to significant immunogenic molecules and formulation of strategies to promote their induction in vaginal mucosa may reveal their potential protective effects against trichomoniasis. In this review, we discuss the current understanding of antibody and T cell-mediated immune responses to T. vaginalis and highlight novel insights into the possible role of immune responses in protection against parasite.