The role of bacterial antizyme: From an inhibitory protein to AtoC transcriptional regulator

This review considers the role of bacterial antizyme in the regulation of polyamine biosynthesis and gives new perspectives on the involvement of antizyme in other significant cellular mechanisms. Antizyme is a protein molecule induced by the end product of the enzymic reaction that it inhibits, in a non-competitive manner. The bacterial ornithine decarboxylase is regulated by nucleotides, phosphorylation and antizyme. The inhibition of ornithine decarboxylase by antizyme can be relieved to different degrees by DNA or by a variety of synthetic nucleic acid polymers, attributed to a specific interaction between nucleic acid and antizyme. Recently, this interplay between bacterial antizyme and nucleic acid was determined by discerning an additional function to antizyme that proved to be the atoC gene product, encoding the response regulator of the bacterial two-component system AtoS-AtoC. The gene located just upstream of atoC encodes the sensor kinase, named AtoS, that modulates AtoC activity. AtoC regulates expression of atoDAEB operon which is involved in short-chain fatty acid metabolism. Antizyme is thus referred to as AtoC, functioning both as a post-translational and transcriptional regulator. Also, the AtoS-AtoC signal transduction system in E. coli has a positive regulatory role on poly-(R)-3-hydroxybutyrate biosynthesis. The properties and gene structural similarities of antizymes from different organisms were compared. It was revealed that conserved domains are present mostly in the C-domain of all antizymes. BLAST analysis of the E. coli antizyme protein (AtoC) showed similarities around 69–58% among proteobacteria, g-proteobacteria, enterobacteria and the thermophilic bacterium Thermus thermophilus. A working hypothesis is proposed for the metabolic role of antizyme (AtoC) describing the significant biological implications of this protein molecule. Whether antizymes exist to other enzymes in different tissues, meeting the criteria discussed in the text remains to be elucidated

Thermus thermophilus genome analysis: benefits and implications

The genome sequence analysis of Thermus thermophilus HB27, a microorganism with high biotechnological potential, has recently been published. In that report, the chromosomal and the megaplasmid sequence were compared to those of other organisms and discussed on the basis of their physiological and metabolic features. Out of the 2,218 putative genes identified through the large genome sequencing project, a significant number has potential interest for biotechnology. The present communication will discuss the accumulating information on molecules participating in fundamental biological processes or having potential biotechnological importance

Effect of polyamines and synthetic polyamine-analogues on the expression of antizyme (AtoC) and its regulatory genes

BACKGROUND: In bacteria, the biosynthesis of polyamines is modulated at the level of transcription as well as post-translationally. Antizyme (Az) has long been identified as a non-competitive protein inhibitor of polyamine biosynthesis in E. coli. Az was also revealed to be the product of the atoC gene. AtoC is the response regulator of the AtoS-AtoC two-component system and it functions as the positive transcriptional regulator of the atoDAEB operon genes, encoding enzymes involved in short chain fatty acid metabolism. The antizyme is referred to as AtoC/Az, to indicate its dual function as both a transcriptional and post-translational regulator. RESULTS: The roles of polyamines on the transcription of atoS and atoC genes as well as that of atoDAEB(ato) operon were studied. Polyamine-mediated induction was tested both in atoSC positive and negative E. coli backgrounds by using β-galactosidase reporter constructs carrying the appropriate promoters patoDAEB, patoS, patoC. In addition, a selection of synthetic polyamine analogues have been synthesized and tested for their effectiveness in inducing the expression of atoC/Az, the product of which plays a pivotal role in the feedback inhibition of putrescine biosynthesis and the transcriptional regulation of the ato operon. The effects of these compounds were also determined on the ato operon expression. The polyamine analogues were also tested for their effect on the activity of ornithine decarboxylase (ODC), the key enzyme of polyamine biosynthesis and on the growth of polyamine-deficient E. coli. CONCLUSION: Polyamines, which have been reported to induce the protein levels of AtoC/Az in E. coli, act at the transcriptional level, since they cause activation of the atoC transcription. In addition, a series of polyamine analogues were studied on the transcription of atoC gene and ODC activity

Synthesis, Structure, and Antiproliferative Activity of Three Gallium(III) Azole Complexes

As part of our interest into the bioinorganic chemistry of gallium, gallium(III) complexes of the azole ligands 2,1,3-benzothiadiazole (btd), 1,2,3-benzotriazole (btaH), and 1-methyl-4,5-diphenylimidazole (L) have been isolated. Reaction of btaH or btd with GaBr3 or GaCl3 resulted in the mononuclear complexes [GaBr3(btaH)2] (1) and [GaCl3(btd)2] (2), respectively, while treatment of GaCl3 with L resulted in the anionic complex (LH)2[GaCl4] (3). All three complexes were characterized by single-crystal X-ray crystallography and IR spectroscopy, while their antiproliferative activities were investigated against a series of human and mouse cancer cell lines

GEOMATICS AND CIVIL ENGINEERING INNOVATIVE RESEARCH ON HERITAGE: INTRODUCING THE “ENGINEER” PROJECT

This paper aims to introduce the concept and objectives of a recently supported European project entitled “Geomatics and Civil Engineering Innovative Research on Heritage”, in short ENGINEER. The ENGINEER project visions to enhance and extend inter- departmental multidisciplinary research activities of the Department of Civil Engineering & Geomatics of the Cyprus University of Technology through coordination and support actions as well as through targeted research activities with the support of European leading institutions. Project tasks aim to fill research multidisciplinary gaps, push, and extend knowledge into new and innovative fields dealing with the monitoring, digitization, visualization, and preservation of ancient monuments and cultural heritage sites, assisting their protection, promotion, and safeguarding

Escherichia coli genome-wide promoter analysis: Identification of additional AtoC binding target elements

<p>Abstract</p> <p>Background</p> <p>Studies on bacterial signal transduction systems have revealed complex networks of functional interactions, where the response regulators play a pivotal role. The AtoSC system of <it>E. coli </it>activates the expression of <it>atoDAEB </it>operon genes, and the subsequent catabolism of short-chain fatty acids, upon acetoacetate induction. Transcriptome and phenotypic analyses suggested that <it>atoSC </it>is also involved in several other cellular activities, although we have recently reported a palindromic repeat within the <it>atoDAEB </it>promoter as the single, <it>cis</it>-regulatory binding site of the AtoC response regulator. In this work, we used a computational approach to explore the presence of yet unidentified AtoC binding sites within other parts of the <it>E. coli </it>genome.</p> <p>Results</p> <p>Through the implementation of a computational <it>de novo </it>motif detection workflow, a set of candidate motifs was generated, representing putative AtoC binding targets within the <it>E. coli </it>genome. In order to assess the biological relevance of the motifs and to select for experimental validation of those sequences related robustly with distinct cellular functions, we implemented a novel approach that applies Gene Ontology Term Analysis to the motif hits and selected those that were qualified through this procedure. The computational results were validated using Chromatin Immunoprecipitation assays to assess the <it>in vivo </it>binding of AtoC to the predicted sites. This process verified twenty-two additional AtoC binding sites, located not only within intergenic regions, but also within gene-encoding sequences.</p> <p>Conclusions</p> <p>This study, by tracing a number of putative AtoC binding sites, has indicated an AtoC-related cross-regulatory function. This highlights the significance of computational genome-wide approaches in elucidating complex patterns of bacterial cell regulation.</p

Pediatric trauma and emergency surgery: an international cross-sectional survey among WSES members

Background: In contrast to adults, the situation for pediatric trauma care from an international point of view and the global management of severely injured children remain rather unclear. The current study investigates structural management of pediatric trauma in centers of different trauma levels as well as experiences with pediatric trauma management around the world. Methods: A web-survey had been distributed to the global mailing list of the World Society of Emergency Surgery from 10/2021-03/2022, investigating characteristics of respondents and affiliated hospitals, case-load of pediatric trauma patients, capacities and infrastructure for critical care in children, trauma team composition, clinical work-up and individual experiences with pediatric trauma management in response to patients´ age. The collaboration group was subdivided regarding sizes of affiliated hospitals to allow comparisons concerning hospital volumes. Comparable results were conducted to statistical analysis. Results: A total of 133 participants from 34 countries, i.e. 5 continents responded to the survey. They were most commonly affiliated with larger hospitals (&gt; 500 beds in 72.9%) and with level I or II trauma centers (82.0%), respectively. 74.4% of hospitals offer unrestricted pediatric medical care, but only 63.2% and 42.9% of the participants had sufficient experiences with trauma care in children ≤ 10 and ≤ 5&nbsp;years of age (p = 0.0014). This situation is aggravated in participants from smaller hospitals (p &lt; 0.01). With regard to hospital size (≤ 500 versus &gt; 500 in-hospital beds), larger hospitals were more likely affiliated with advanced trauma centers, more elaborated pediatric intensive care infrastructure (p &lt; 0.0001), treated children at all ages more frequently (p = 0.0938) and have higher case-loads of severely injured children &lt; 12&nbsp;years of age (p = 0.0009). Therefore, the majority of larger hospitals reserve either pediatric surgery departments or board-certified pediatric surgeons (p &lt; 0.0001) and in-hospital trauma management is conducted more multi-disciplinarily. However, the majority of respondents does not feel prepared for treatment of severe pediatric trauma and call for special educational and practical training courses (overall: 80.2% and 64.3%, respectively). Conclusions: Multi-professional management of pediatric trauma and individual experiences with severely injured children depend on volumes, level of trauma centers and infrastructure of the hospital. However, respondents from hospitals at all levels of trauma care complain about an alarming lack of knowledge on pediatric trauma management

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Histamine in two component system-mediated bacterial signaling

Histamine is a key mediator governing vital cellular processes in mammals beyond its decisive role in inflammation. Recent evidence implies additional actions in both eukaryotes and prokaryotes. Besides its function in host defense against bacterial infections, histamine elicits largely undefined actions in microorganisms that may contribute to bacteria-host interactions. Bacterial proliferation and adaptation are governed by sophisticated signal transduction networks, including the versatile two-component systems (TCSs) that comprise sensor histidine kinases and response regulators and rely on phosphotransfer mechanisms to exert their modulatory function. The AtoSC TCS regulates fundamental cellular processes such as short-chain fatty acid metabolism, poly-(R)-3-hydroxybutyrate (cPHB) biosynthesis and chemotaxis in Escherichia coli. The implication of exogenous histamine in the AtoSC-mediated cPHB biosynthesis and in E. coli chemotactic behavior is indicative of a putative function of histamine in bacterial physiology. The data raise questions on the significance of histamine actions in bacteria-host symbiosis, dysbiosis and pathogenicity as well as on the possible consequences upon therapeutic administration of histamine receptor-targeting agents and in particular ligands of the recently identified immunomodulatory H-4 receptor