Molecular Microbiology

The uracil permease UraA of Escherichia coli is a structurally known prototype for the ubiquitous Nucleobase-Ascorbate Transporter (NAT) or Nucleobase-Cation Symporter-2 (NCS2) family and represents a well-defined subgroup of bacterial homologs that remain functionally unstudied. Here, we analyze four of these homologs, including RutG of E. coli which shares 35% identity with UraA and is encoded in the catabolic rut (pyrimidine utilization) operon. Using amplified expression in E. coli K-12, we show that RutG is a high-affinity permease for uracil, thymine and, at low efficiency, xanthine and recognizes also 5-fluorouracil and oxypurinol. In contrast, UraA and the homologs from Acinetobacter calcoaceticus and Aeromonas veronii are permeases specific for uracil and 5-fluorouracil. Molecular docking indicates that thymine is hindered from binding to UraA by a highly conserved Phe residue which is absent in RutG. Site-directed replacement of this Phe with Ala in the three uracil-specif...

NCS1 proteins are H 1 or Na 1 symporters responsible for the uptake of purines, pyrimidines or related metabolites in bacteria, fungi and some plants. Fungal NCS1 are classified into two evolutionary and structurally distinct subfamilies, known as Fur-and Fcy-like transporters. These subfamilies have expanded and functionally diversified by gene duplications. The Fur subfamily of the model fungus Aspergillus nidulans includes both major and cryptic transporters specific for uracil, 5fluorouracil, allantoin or/and uric acid. Here we functionally analyse all four A. nidulans Fcy transporters (FcyA, FcyC, FcyD and FcyE) with previously unknown function. Our analysis shows that FcyD is moderate-affinity, low-capacity, highly specific adenine transporter, whereas FcyE contributes to 8-azaguanine uptake. Mutational analysis of FcyD, supported by homology modelling and substrate docking, shows that two variably conserved residues (Leu356 and Ser359) in transmembrane segment 8 (TMS8) are critical for transport kinetics and specificity differences among Fcy transporters, while two conserved residues (Phe167 and Ser171) in TMS3 are also important for function. Importantly, mutation S359N converts FcyD to a promiscuous nucleobase transporter capable of recognizing adenine, xanthine and several nucleobase analogues. Our results reveal the importance of specific residues in the functional evolution of NCS1 transporters.

Cells possess stress-activated protein kinase (SAPK) signalling pathways, which are activated practically in response to any cellular insult, regulating responses for survival and adaptation to harmful environmental changes. To understand the function of SAPK pathways in T. atroviride, mutants lacking the MAPKK Pbs2 and the MAPK Tmk3 were analysed under several cellular stresses, and in their response to light. All mutants were highly sensitive to cellular insults such as osmotic and oxidative stress, cell wall damage, high temperature, cadmium, and UV irradiation. Under oxidative stress, the Tmk3 pathway showed specific roles during development, which in conidia are essential for tolerance to oxidant agents and appear to play a minor role in mycelia. The function of this pathway was more evident in Dpbs2 and Dtmk3 mutant strains when combining oxidative stress or cell wall damage with light. Light stimulates tolerance to osmotic stress through Tmk3 independently of the photoreceptor Blr1. Strikingly, photoconidiation and expression of blue light regulated genes was severally affected in Dtmk3 and Dpbs2 strains, indicating that this pathway regulates light responses. Furthermore, Tmk3 was rapidly phospho-rylated upon light exposure. Thus, our data indicate that Tmk3 signalling cooperates with the Blr photoreceptor complex in the activation of gene expression.

SummaryThe soil fungus Trichoderma harzianum is a mycoparasitic fungus known for its use as a biocontrol agent of phytopathogenic fungi. Among other factors, Trichoderma produces a series of antibiotics and fungal cell wall‐degrading enzymes. These enzymes are believed to play an important role in mycoparasitism. Among the hydrolytic enzymes, we have identified a basic proteinase (Prb1) which is induced by either autoclaved mycelia, fungal cell wall preparation or chitin; however, the induction does not occur in the presence of glucose. The proteinase was purified and biochemically characterized as a serine proteinase of 31 kDa and pl 9.2. Based on the sequence of three internal peptides, synthetic oligonudeotide probes were designed. These probes allowed subsequent isolation of a cDNA and its corresponding genomic clone. The deduced amino acid sequence indicates that the proteinase is synthesized as a pre‐proenzyme and allows its classification as a serine proteinase. Northen analy...

DNA polymerase kappa (Polk) is a low-fidelity polymerase that has the ability to bypass several types of lesions. The biological role of this enzyme, a member of the DinB subfamily of Y-family DNA polymerases, has remained elusive. In this report, we studied one of the two copies of Polk from the protozoan Trypanosoma cruzi (TcPolk). The role of this TcPolk copy was investigated by analysing its subcellular localization, its activities in vitro, and performing experiments with parasites that overexpress this polymerase. The TcPOLK sequence has the N-terminal extension which is present only in eukaryotic DinB members, but its C-terminal region is more similar to prokaryotic and archaeal counterparts since it lacks C 2HC motifs and PCNA interaction domain. Our results indicate that in contrast to its previously described orthologues, this polymerase is localized to mitochondria. The overexpression of TcPOLK increases T. cruzi resistance to hydrogen peroxide, and in vitro polymerization assays revealed that TcPolk efficiently bypasses 8-oxoguanine lesions. Remarkably, our results also demonstrate that the DinB subfamily of polymerases can participate in homologous recombination, based on our findings that TcPolk increases T. cruzi resistance to high doses of gamma irradiation and zeocin and can catalyse DNA synthesis within recombination intermediates.

The development of B2B relations is researched by many scholars. Besides dealing with the stages of the lifecycle the aim of this study is to introduce client groups in Slovakia with the help of the factors that influence relationships on the advertising market the most. After joining an international research group, besides dealing with the above mentioned factors, in our primary research we set out to research Slovak client groups on the Slovak advertising market and to describe them on the basis of their behaviour. We suppose that clients can be segmented on the advertising market just like on every other market. Thus, our hypothesis is the following: There are distinctive client groups in the early stage of the lifecycle model. In order to ensure comparability, in our survey we used a questionnaire that was already successfully tested in Hong Kong. Our respondents were Slovakian advertising agencies and their clients. Our research results showed that the researched Slovak businesses can be put into two groups in the early stage of the business relations: the risk-averse segment and the risk taking segment. Thus, we consider the carrying out of segmentation also on the advertising market important, which can result in offering customised services to clients.

In today´s competitive business environment, to achieve and retain business success, it is essential to devote sufficient attention to building business relationships. Recognition of factors, influencing the success of business relationships, has long been a topic of professionals and those who are interested in this field. When getting in touch with a customer, the company aims to establish a strong relationship with the customer, to win indifferent customers and to create customer loyalty. Based on the factors above, we found it important to determine the perception of the importance of factors which determine contacting customers the most from the customers´ point of view in the market of advertising agencies. Regarding further successful cooperation, it is essential to address customers with a proper campaign. Therefore, this paper aims to identify emerging customer groups when building relationships in the advertising market, thus facilitating the realization of personalized ca...

In this paper, we propose a computational multiagent model of a bacterial light-producing communication system, termed quorum sensing (QS). Specifically, we propose a bottom-up agent-based approach combined with Ordinary Differential Equations, which abstract the intracellular dynamics, such as a proposed bioluminescence model. Results show that bacteria cells have a metabolism allowing them to grow, reproduce, interact, and cooperate at the population level to exhibit nearoptimal light producing behaviors. The ultimate goal is to develop a self-regulated network in which the rules governing the formation of the network are linked to the internal dynamics of its units without any centralized control. Such a bacterial-inspired networks, can address issues such as mobility, and energy that are key factors for the development of new self-organized network such as mobile Ad-hoc networks.

Plant growth and development, much like in animals, is a highly-coordinated process of cell division and differentiation which generate new cell types and tissues. Receptor kinases respond to extra-cellular cues and mediate appropriate downstream gene expression through auto and trans-phosphorylation events. Arabidopsis CRINKLY4 (ACR4) is a plasma membrane localized receptor-like kinase that plays an important role in formative cell division and stem cell differentiation in root tip and initiates lateral root development in Arabidopsis. The Arabidopsis genome also encodes four homologs of ACR4, referred to as Arabidopsis CRINKLY4 Related (AtCRR) proteins. ACR4 and its homologs have equivalent architecture, comprised of an extracellular ligand binding domain, a transmembrane helix, and an intracellular kinase domain. Cell biology, genetic and in vitro biochemical studies have indicated potential interaction partners within the ACR4 family. However, very little is known of the ACR4 mediated network of interactions and the molecular mechanism of its regulation. In this dissertation, we report the identification of the catalytic subunit of Protein Phosphatase 2A-3 isoform (PP2A3c) as the first known substrate for the kinase activity of ACR4 and ACR4-homolog CRK1. We provide evidence of a regulatory reciprocal interaction between the catalytic subunit of PP2A3c and ACR4, with PP2A3c serving the dual role as a substrate for ACR4 kinase and as a regulatory phosphatase in modulating kinase activity. To further advance in vitro biochemical and biophysical studies on the regulation of phosphatase activity, we describe expression and purification of MBP-tagged PP2A3c in E. coli. We demonstrate slow activation of phosphatase activity of PP2A3c over vii time and further demonstrate the ability of the PP2A chaperone, PTPA, to more rapidly activate phosphatase activity in trans, in the presence of ATP. We provide a biochemical context to these results and the usefulness of our system in investigating the role of posttranslational modifications. Additionally, we have characterized the biochemical properties of the recombinantly expressed intracellular kinase domain of the ACR4 homolog, CRK1. The in-planta expression of this RLK in the cells of the root tip overlaps the expression pattern of ACR4 and PP2A and we demonstrate that PP2A3c is also a substrate for CRK1. Mass spectrometry analysis confirmed >30 sites of phosphorylation at Serine, Threonine and Tyrosine residues, spanning the entire intracellular domain of CRK1. Mutagenesis experiments identified phosphorylation sites within the activation loop that had both positive and negative effects on the kinase activity of CRK1. Finally, we describe the generation of a highly specific monoclonal antibody to the kinase domain of ACR4. downstream signal transduction which guide a host of cellular responses such as cell growth, proliferation and differentiation [13,14]. This dissertation is organized into six chapters. Chapter 1 briefly reviews the current state of knowledge of plant receptor-like kinases in general, the role of ACR4 and homologs and the emerging importance of PP2A as a major regulator of receptor function. Chapter 2 has been published in the Proceedings of the National Academy of Sciences, USA [15] in a collaborative study and my contribution as a first author is summarized. This paper for the first time describes the characterization of PP2A3c as a substrate for ACR4 and a regulator of formative cell division in the Arabidopsis root. Chapter 3 is a manuscript that has been prepared for publication and describes the expression and purification of MBP-tagged PP2A3c and the activation of phosphatase activity in trans via the protein chaperone PTPA. Chapter 4 is prepared as a manuscript describing the characterization of the SUMO-tagged intracellular kinase domain of the ACR4 homolog, CRK1. This includes characterization of basic kinetic properties, the role of phosphorylation sites in the activation loop through mutagenesis studies and interaction with PP2A3c. Chapter 5 describes the path to the generation of a monoclonal antibody to the kinase domain of ACR4 and its value as a reagent for in vivo biological studies. Lastly, Chapter 6 is a general conclusion that draws together the work described in the previous chapters and outlines potential future directions.

SummaryThe Corynebacterium glutamicum fda gene encoding fructose‐ 1,6‐btphosphate (FBP) aldolase has been isolated by complementation of an Escherichia coli mutant. The nucleotide sequence of a 3371 bp chromosomal fragment containing the C. glutamicum fda gene was determined. The N‐terminal amino acid sequence of C. glutamicum FBP aldolase identified the correct initiation site for the fda gene, and a molecular weight of 37092 was predicted for the fda polypeptide. S1 nuclease mapping identified the transcriptional start site, and Northern hybridization analysis indicated that the fda gene encodes a single 1.3 kb transcript. The primary structure of C. glutamicum FBP aldolase shows strong homology to class 11 FBP aldolases. Conservation of primary structure was observed between class I and class II aldolases, but several residues essential for catalytic activity in class I aldolases were absent from class II aldolases.

Aquaculture environments can become reservoirs of antibiotic-resistant strains of faecal bacteria including enterococci which are capable of contributing to the spread of antimicrobial resistance in the marine environment. The aim of this study was to characterize the antimicrobial resistance profile of Enterococcus species from various aquacultures (fish ponds) in Benin City, Edo State. A total of 376 water samples were obtained from four different fish ponds between February and July, 2015 and were investigated for the presence of Enterococcus species using standard culture based methods. The antimicrobial susceptibility profiles of the isolates were determined by using Kirby-Bauer disc diffusion method. From the 376 water samples analyzed for the presence of enterococci isolates, 100 isolates each from Enterococcus faecalis and Enterococcus faecium were isolated from the four fish ponds investigated. The mean enterococal counts from the four fish ponds investigated ranged from 4±0.01 × 10 2 to 12±0.17×10 2 cfu/ml. Statistical analysis reveals that there was a significant difference observed in the mean enterococcal counts obtained from the four different fish ponds in the study (p< 0.05). The distribution of the enterococcal isolates in the study from February to July reveals that 50 isolates from each pond were characterized. Statistical analysis also reveals that there was a significant difference observed in the distribution of the enterococcal isolates from the fish ponds (p< 0.05). High level resistance was observed against six antibiotics used in the study such that 15 enterococcal isolates displayed marked resistance to the action of trimethoprim, chloramphenicol, erythromycin, oxytetracycline, sulfamethoxazole, and ciprofloxacin. Adherence to adequate and proper use of manure products and frequent discharge of water from fish pond will reduce the high level of antimicrobial resistance in Enterococcus species isolated from fish ponds and also reduce the potential risk to human health.

Interaction of the TolB box of Group A colicins with the TolB protein in the periplasm of Escherichia coli cells promotes transport of the cytotoxic domain of the colicin across the cell envelope. The crystal structure of a complex between a 107-residue peptide (TA(1-107)) of the translocation domain of colicin A (ColA) and TolB identified the TolB box as a 12-residue peptide that folded into a distorted hairpin within a central canyon of the beta-propeller domain of TolB. Comparison of this structure with that of the colicin E9 (ColE9) TolB box-TolB complex, together with site-directed mutagenesis of the ColA TolB box residues, revealed important differences in the interaction of the two TolB boxes with an overlapping binding site on TolB. Substitution of the TolB box residues of ColA with those of ColE9 conferred the ability to competitively recruit TolB from Pal but reduced the biological activity of the mutant ColA. This datum explains (i) the difference in binding affinities of...

Cells possess stress-activated protein kinase (SAPK) signalling pathways, which are activated practically in response to any cellular insult, regulating responses for survival and adaptation to harmful environmental changes. To understand the function of SAPK pathways in T. atroviride, mutants lacking the MAPKK Pbs2 and the MAPK Tmk3 were analysed under several cellular stresses, and in their response to light. All mutants were highly sensitive to cellular insults such as osmotic and oxidative stress, cell wall damage, high temperature, cadmium, and UV irradiation. Under oxidative stress, the Tmk3 pathway showed specific roles during development, which in conidia are essential for tolerance to oxidant agents and appear to play a minor role in mycelia. The function of this pathway was more evident in Dpbs2 and Dtmk3 mutant strains when combining oxidative stress or cell wall damage with light. Light stimulates tolerance to osmotic stress through Tmk3 independently of the photoreceptor Blr1. Strikingly, photoconidiation and expression of blue light regulated genes was severally affected in Dtmk3 and Dpbs2 strains, indicating that this pathway regulates light responses. Furthermore, Tmk3 was rapidly phospho-rylated upon light exposure. Thus, our data indicate that Tmk3 signalling cooperates with the Blr photoreceptor complex in the activation of gene expression.

 Ustilago maydis (U. maydis) is the causal agent of maize smut disease. During the colonization process, the fungus secretes effector proteins which suppress immune responses and redirect the host metabolism in favor of the pathogen. As effectors play a critical role during plant colonization, their identification and functional characterization is essential to understanding biotrophy and disease.  Using biochemical, molecular, and transcriptomic techniques, we performed a functional characterization of the U. maydis effector Jasmonate/Ethylene signaling inducer 1 (Jsi1).  Jsi1 interacts with several members of the plant co-repressor family Topless/Topless related (TPL/TPR). Jsi1 expression in Zea mays (Z. mays) and Arabidopsis thaliana (A. thaliana) leads to transcriptional induction of the ethylene response factor (ERF) branch of the jasmonate/ethylene (JA/ET) signaling pathway. In A. thaliana, activation of the ERFbranch leads to biotrophic susceptibility. Jsi1 likely activates the ERF-branch via an EAR motif, which resembles EAR motifs from plant ERF transcription factors, that interacts with TPL/TPR proteins.  EAR motif-containing effector candidates were identified from different fungal species including Magnaporthe oryzae, Sporisorium scitamineum, and Sporisorium reilianum. Interaction between plant TPL proteins and these effector candidates from biotrophic and hemibiotrophic fungi indicates the convergent evolution of effectors modulating the TPL/TPR co-repressor hub.

Plant pathogenic Pseudomonas syringae strains harbour a type III secretion pathway suggested to be involved in the delivery of effector proteins from the bacteria into plant cells. During plant interaction, the bacteria apparently produce surface appendages, termed Hrp pili, that are indispensable for the secretion process. We have created an insertion mutation library, as well as deletion mutations to hrpA, the structural gene encoding Hrp pilin. Analysis of the mutants revealed gene regions important for hrpA expression, pilus assembly and pilus‐dependent autoagglutination of the bacteria. The majority of insertions in the amino‐terminal half of the pilin were tolerated without bacterial interaction with plants being affected, while the carboxy‐terminus appeared to be needed for pilus assembly. Insertions in the 5′ non‐translated region and the first codons within the open reading frame affected mRNA production or stability and abolished protein production.

Background. Extended-spectrumβ-lactamase-producing organisms causing urinary tract infections are increasing in incidence and pose a major impendence to health-care facility, having limited therapeutic options. This study aimed to assess the prevalence of ESBLs in Enterobacteriaceae isolates causing urinary tract infections in Gaza strip, Palestine, and to characterizeβ-lactamase types and associated resistance genes.Methods. Eighty-five Enterobacteriaceae isolates were recovered from urinary tract infections within three months in Gaza Strip hospitals. The characterization ofβ-lactamase genes and the genetic environments of CTX-M, the identification of associated resistance genes, and the presence and characterization of integrons were tested by PCR and sequencing.Results. The occurrence rate of ESBL among tested isolates was 30 (35.3%), and among ESBL-positive isolates,blaCTX-Mwas the highest followed byblaTEM. ESBL-CTX-M-1 group was confirmed in 93.3%, and the remaining carried C...

Like other eukaryotes, trypanosomes have an essential type II fatty acid synthase in their mitochondrion. We have investigated the function of this synthase in bloodstream-form parasites by studying the effect of a conditional knockout of acyl carrier protein (ACP), a key player in this fatty acid synthase pathway. We found that ACP depletion not only caused small changes in cellular phospholipids but also, surprisingly, caused changes in the kinetoplast. This structure, which contains the mitochondrial genome in the form of a giant network of several thousand interlocked DNA rings (kinetoplast DNA [kDNA]), became larger in some cells and smaller or absent in others. We observed the same pattern in isolated networks viewed by either fluorescence or electron microscopy. We found that the changes in kDNA size were not due to the disruption of replication but, instead, to a defect in segregation. kDNA segregation is mediated by the tripartite attachment complex (TAC), and we hypothesize that one of the TAC components, a differentiated region of the mitochondrial double membrane, has an altered phospholipid composition when ACP is depleted. We further speculate that this compositional change affects TAC function, and thus kDNA segregation.

Like other eukaryotes, trypanosomes have an essential type II fatty acid synthase in their mitochondrion. We have investigated the function of this synthase in bloodstream-form parasites by studying the effect of a conditional knockout of acyl carrier protein (ACP), a key player in this fatty acid synthase pathway. We found that ACP depletion not only caused small changes in cellular phospholipids but also, surprisingly, caused changes in the kinetoplast. This structure, which contains the mitochondrial genome in the form of a giant network of several thousand interlocked DNA rings (kinetoplast DNA [kDNA]), became larger in some cells and smaller or absent in others. We observed the same pattern in isolated networks viewed by either fluorescence or electron microscopy. We found that the changes in kDNA size were not due to the disruption of replication but, instead, to a defect in segregation. kDNA segregation is mediated by the tripartite attachment complex (TAC), and we hypothesize that one of the TAC components, a differentiated region of the mitochondrial double membrane, has an altered phospholipid composition when ACP is depleted. We further speculate that this compositional change affects TAC function, and thus kDNA segregation.

SummaryLipoic acid is a cofactor required for intermediary metabolism that is either synthesized de novo or acquired from environmental sources. The bacterial pathogen Staphylococcus aureus encodes enzymes required for de novo biosynthesis, but also encodes two ligases, LplA1 and LplA2, that are sufficient for lipoic acid salvage during infection. S. aureus also encodes two H proteins, GcvH of the glycine cleavage system and the homologous GcvH‐L encoded in an operon with LplA2. GcvH is a recognized conduit for lipoyl transfer to α‐ketoacid dehydrogenase E2 subunits, while the function of GcvH‐L remains unclear. The potential to produce two ligases and two H proteins is an unusual characteristic of S. aureus that is unlike most other Gram positive Firmicutes and might allude to an expanded pathway of lipoic acid acquisition in this microorganism. Here, we demonstrate that LplA1 and LplA2 facilitate lipoic acid salvage by differentially targeting lipoyl domain‐containing proteins; Lp...

The capitalist expansion based on ICTs configured could be considered an ascending Kondratiev wave, understood since the beginning of the 1980s to the outbreak of the financial crisis in 2008. This expansive wave has had its dynamic centre in the United States capitalism, originator and leader of digital and network technology. This Kondratiev has limitations of amplitude and rhythm that have resulted in a premature decline in the productivity performance. The weakness of the fifth Kondratiev is not due to a problem of technological exhaustion but to a precarious socio-political and institutional support in the hegemonic country. This means that the US digital monopolies supported by the peculiar institutionality of that country concentrate the economic benefits, causing general effects of exclusion and social marginalization. The only United States competitor is the People's Republic of China, which has managed and created a successful digital economy, which in the span of a decade could contest the hegemony of the leading country. This competitive struggle, which is not only commercial but politico-institutional, will determine if the fifth Kondratiev, now in a phase of economic depression, experiences a rebound, mutates in another Kondratiev based on artificial intelligence or opens a prolonged period of uncertainty and instability global accentuated. The deregulation and the absence of counterweights characteristic of United States institutions explain the conversion of powerful digital technology into a disruptive factor instead of an integrating factor. The other world powers, with the exception of the People's Republic of China, have become just users of digital products and services generated by the United States. Only the People's Republic of China has ventured, and successfully, to become a digital producer, competing directly with American monopolies. But to the extent that this competition is not primarily about trade and market in the conventional sense, but a clash of normative models of social exploitation of the digitalization, we are properly before a struggle for world hegemony.

The biosynthetic machinery for cell wall polysaccharide (CWPS) production in lactococci is encoded by a large gene cluster, designated cwps. This locus displays considerable variation among lactococcal genomes, previously prompting a classification into three distinct genotypes (A–C). In the present study, the cwps loci of 107 lactococcal strains were compared, revealing the presence of a fourth cwps genotype (type D). Lactococcal CWPSs are comprised of two saccharidic structures: a peptidoglycan‐embedded rhamnan backbone polymer to which a surface‐exposed, poly/oligosaccharidic side‐chain is covalently linked. Chemical structures of the side‐chain of seven lactococcal strains were elucidated, highlighting their diverse and strain‐specific nature. Furthermore, a link between cwps genotype and chemical structure was derived based on the number of glycosyltransferase‐encoding genes in the cwps cluster and the presence of conserved genes encoding the presumed priming glycosyltransferas...

Bacteriophage replication requires specific host-recognition. Some siphophages harbour a large complex, the baseplate, at the tip of their non-contractile tail. This baseplate holds receptor binding proteins (RBPs) that can recognize the host cell-wall polysaccharide (CWPS) and specifically attach the phage to its host. While most phages possess a dedicated RBP, the phage J-1 that infects Lactobacillus casei seemed to lack one. It has been shown that the phage J-1 distal tail protein (Dit) plays a role in host recognition and that its sequence comprises two inserted modules compared with &#39;classical&#39; Dits. The first insertion is similar to carbohydrate-binding modules (CBMs), whereas the second insertion remains undocumented. Here, we determined the structure of the second insertion and found it also similar to several CBMs. Expressed insertion CBM2, but not CBM1, binds to L. casei cells and neutralize phage attachment to the bacterial cell wall and the isolated and purified ...

Mycoplasma hominis contains a variable adherence‐associated (vaa) gene. To classify variants of the vaa genes, we examined 42 M. hominis isolates by PCR, DNA sequencing and immunoblotting. This uncovered the existence of five gene categories. Comparison of the gene types revealed a modular composition of the Vaa proteins. The proteins constituted a conserved N‐terminal part followed by a varying number of interchangeable cassettes encoding approximately 110 amino acids with conserved sequence boxes flanking the cassettes. The interchangeable cassettes showed a high mutual homology and a conserved leucine zipper motif. The smallest product contained only one cassette and the largest five. Additionally, two types of stop mutations caused by substitutions resulting in the expression of truncated Vaa proteins were observed. Our results expand the known potential of the Vaa system in generating antigen variation.

This retrospective study aims to analyze the antibiotic resistance profiles of bacteria isolated at the central laboratory of the National Hospital Center of Nouakchott, Mauritania, over a period of two years (January 2020-December 2021). A total of 511 non-duplicated clinical isolates were examined, from a diverse range of biological samples, including urine, pus, genital swabs, puncture fluids and blood cultures. All samples were taken from hospitalized and ambulatory patients in Nouakchott and only those with complete identification and sensitivity profiles were included. Gram-negative bacteria (GNB) accounted for 78.3% of isolates, while Gram-positive cocci (GPC) accounted for 21.7% of strains. GNB were mainly represented by enterobacteria (98.0%), and Escherichia coli was the most frequently isolated species (54.8%). The Gram-positive cocci were mainly Staphylococcus aureus (17.8%). Susceptibility testing was performed using the VITEK® 2 system and agar diffusion methods in accordance with EUCAST and CA-SFM recommendations. They revealed alarming levels of resistance to commonly used antibiotics. E. coli showed 80.1% resistance to extended spectrum beta-lactamases (ESBLs) and 33.6% resistance to ciprofloxacin, with 13.2% of isolates producing extended-spectrum beta-lactamases (ESBLs). K. pneumoniae showed an increasing prevalence and increasing resistance to third-generation cephalosporins and carbapenems. It also showed reduced efficacy on all methicillin species. The prevalence of ESBL in this species was 23.9% and its resistance to third-generation cephalosporins and carbapenems increased (4.8%). In the face of rising resistance, the study recommends rational use of antibiotics, reinforced microbiological surveillance and awareness-raising among medical staff and the general public to limit self-medication and the spread of multi-resistant bacteria.

Two pyoverdin-ampicillin conjugates were synthesized and their structures were confirmed by mass spectrometry and NMR spectroscopy. In contrast to ampicillin, the conjugates exhibited high antibacterial activity against Pseudomonas aeruginosa ATCC 15692 and ATCC 27853, effective only against the strain which is using the parent pyoverdin for iron uptake. This suggests that the conjugates enter the bacterial cell via the ferripyoverdin uptake pathway. Growth stimulation studies with conjugates hydrolysed

The fungal pathogen Candida albicans can transition from budding to hyphal growth, which promotes biofilm formation and invasive growth into tissues. Stimulation of adenylyl cyclase to form cAMP induces hyphal morphogenesis. The failure of cells lacking adenylyl cyclase (cyr1Δ) to form hyphae has suggested that cAMP signaling is essential for hyphal growth. However, cyr1Δ mutants also grow slowly and have defects in morphogenesis, making it unclear whether hyphal inducers must stimulate cAMP, or if normal basal levels of cAMP are required to maintain cellular health needed for hyphal growth. Interestingly, supplementation of cyr1Δ cells with low levels of cAMP enabled them to form hyphae in response to the inducer N-acetylglucosamine (GlcNAc), suggesting that a basal level of cAMP is sufficient for stimulation. Furthermore, we isolated fastergrowing cyr1Δ pseudorevertant strains that can be induced to form hyphae even though they lack cAMP. The pseudorevertant strains were not induced by CO 2 , consistent with reports that CO 2 directly stimulates adenylyl cyclase. Mutational analysis showed that induction of hyphae in a pseudorevertant strain was independent of RAS1, but was dependent on the EFG1 transcription factor that acts downstream of protein kinase A. Thus, cAMP-independent signals contribute to the induction of hyphal responses.

The most dangerous issue in the healthcare arises is outbreak of the antibiotic-resistant bacteria worldwide. The randomness of Salmonella infections rely on its serotypes and the immune response of the host. Children up to age of 5 years and patients of older age are prone to the salmonella infections. The virulence genes of Salmonella encodes five different groups of Cell invasion proteins (CIPs), including Sip A, B, C, D and E. Upon contact with the target cell, SipB undergo 'type III' export from the bacterial cytoplasm and translocate into the cell membrane. Caspase-1 activity is essential for the cytotoxicity, and it has been proven that binding of SipB to caspase-1 induces macrophage apoptosis, so functional inhibition of caspase-1 blocks macrophage cytotoxicity. Methods: This study is to determine the components of the natural origin compounds (NOCs) have an anti-bacterial effect (ABE) and capable to prevent the humans from bacterial infection Salmonella enterica serotype typhi. This Salmonella is using the most reliable method is suitable for molecular docking. We used to find out the interaction study between the molecules and the protein. In our study based on the inhibitor of Cell Invasion Protein SipB from Salmonella. We performed In Silico method for screening of all the natural compounds against Cell Invasion Protein SipB inhibition. The results we obtained from molecular docking shown that among 2228 molecules of natural origin from natural product compounds library (20200427-L1400) was retrieved in SDF format from Inhibitor Expert (Selleckchem.com). Fifteen molecules are the best compounds observed through molecular docking and hydrophobic interactions and hydrogen bonding with interaction are proposed as the novel inhibitors against the Cell Invasion Protein SipB from Salmonella. We demonstrate using SwissADME online server tools and DruLito that all fifteen natural molecules has better "drug-likeness and does not violate any Lipinski, Ghose, Veber, Egan or Muegge rules. Importantly, all fifteen natural compounds are more potent in treatment of against Cell Invasion Protein SipB in Salmonella typhi but needs further experimental research.

The epidemiology of bovine and human tuberculosis (TB) was studied in the Federal Capital Territory and Kaduna state of Nigeria using four diagnostic methods; tuberculin test, culture and acid-fast stain of milk, animal (cattle) tissue and human sputum. Two PCR-based molecular techniques (Spoligotyping and Variable Number Tandem Repeat) were used to identify the species and strains of the isolates, while IS61 10-RFLP molecular method was optimised and applied on few samples to deten-nine the efficacy of the method. Of the 967 lactating cows from 57 herds tested for TB, 14.6%, 4% and 81.4% were positive, inconclusive and negative reactors respectively. Tuberculin test also showed that mycobacterial infection was prevalent iii the two management systems studied (nomadic and semi-nomadic), but the effect of management on the prevalence of infection was not significant. However, age was found to play a significant role in the prevalence infection where more positive cases were observed among the older age groups. It was also observed that control policy is either not in place or inadequately implemented in the study area. Of the 156 milk samples collected, 12.6% and 23% were culture and acid-fast positive respectively, while out of the 250 tissue samples 17.3% and 20% were culture and acid-fast positivc respectively. Thi III is finding confirmed a definite relationship between the disease in live and slaughtered cattle. Comparing the three diagnostic methods in List of Contents

The leave extracts of Mirabilis jalapa collected from Uvwie local government were subjected to phytochemical screening, result show that the plant under study contains saponin, flavonoids, alkaloids, terpenoids, resins and phenols. Proximate analysis was carried out to determine ash content, crude protein, crude fibre, moisture content, lipid and nitrogen free extract. The result revealed the presence of high moisture content of 30% and a low Lipid content of 3%. The rest were obtained as follow; ash content 20%, protein content 12.8%, fibre content 8.22% and nitrogen 25.98%. Antimicrobial activity of Mirabilis jalapa leaf was tested on bacterial isolates from the standard laboratory. Bacterial isolates include Bacillus species, Pseudomonas, Micrococcus and E. coli. Five different concentrations (0.1, 0.2, 0.05, 0.025 and 0.012 (mg/ml)) of both the extracting solvents and the extracts were tested on the isolates. The results revealed that Mirabilis Jalapa is a strong antibiotic against E. coli, Bacillus and Pseudomonas but weak against Micrococcus.

SummaryRegulatory network plasticity is a key attribute underlying changes in bacterial gene expression and a source of phenotypic diversity to interact with the surrounding environment. Here, we sought to study the transcriptional circuit of HutC, a regulator of both metabolic and virulence genes of the facultative intracellular pathogen Brucella. Using in silico and biochemical approaches, we identified a novel functional HutC‐binding site upstream of btaE, a trimeric‐autotransporter adhesin involved in the attachment of Brucella to host extracellular matrix components. Moreover, we identified two additional regulators, one of which, MdrA, acts in concert with HutC to exert a combinatorial control of both btaE promoter activity and attachment of Brucella to HeLa cells. Analysis of btaE promoter sequences of different species indicated that this HutC‐binding site was generated de novo by a single point mutation in a virulent Brucella strain, indicative of a transcriptional rewiring...

This research paper aims to discuss the role of the strategies for promoting the relations between banks and their clients and the appropriate means of customer retention besides highlighting the banks’ market share from the perspective of the Jordanian commercial banks’ customers. Its main purpose is to identify the degree of the commercial Jordanian banks’ utilization and maintaining benefits from these ties through marketing activities and customers’ retention strategies in order to enhance their market share. The population of the study consisted of a sample including selected clients from the Jordanian commercial banks (Five clients from every bank). The results revealed that the most active banks that achieved noticeable progress in promoting their ties with their clients were the Arab Bank and the Housing Bank. The study recommended that the Jordanian banks have to give a serious attention to the means and activities which are required to develop such relations because of the...

Listeria monocytogenes is a Gram-positive, facultative intracellular pathogen, causing listeriosis, a foodborne infectious disease with a significant global burden . The ability of this bacterium to withstand high and low temperature, pH and salt concentrations , explains why infections are almost exclusively transmitted by contaminated food. Among the 20 designated species within the genus, the human pathogen L. monocytogenes can be further subdivided by serovars, a phenotypic designation relying upon the structural intricacies of the peptidoglycan-associated wall teichoic acids which define the O-antigens . Twelve different serovars have been described for L. monocytogenes (1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4a, 4b, 4c, 4d, 4e and 7) . More recent data indicate that the virulence-attenuated serovar 3 and (very rare)

The paper deals with the analysis of the impact of public administration on the innovation development. With purposes to identify the main scientific directions of analysis among the scientific community, the authors did the bibliometric study. For the reviews, the authors selected 1167 papers which indexing in Scopus. For the visualising the findings of bibliometric analysis, the VOSviewer was used. The results allow allocating 10 clusters of scientific directions which analysed the issues of innovations and public administrations. The first most significant clusters could «innovation» analysed the efficiency of the public administration through the effectiveness of innovation implementation. The second clusters connected with the government innovation policy and located close to the first clusters. The third cluster «public administration» involved 40 items and 4699 links. The scientists with Italian and American affiliations had the most significant shares of papers. At the same ...

SummaryMalaria parasites grow within erythrocytes, but are also free in host plasma between cycles of asexual replication. As a result, the parasite is exposed to fluctuating levels of Na+ and K+, ions assumed to serve important roles for the human pathogen, Plasmodium falciparum. We examined these assumptions and the parasite&#39;s ionic requirements by establishing continuous culture in novel sucrose‐based media. With sucrose as the primary osmoticant and K+ and Cl− as the main extracellular ions, we obtained parasite growth and propagation at rates indistinguishable from those in physiological media. These conditions abolish long‐known increases in intracellular Na+ via parasite‐induced channels, excluding a requirement for erythrocyte cation remodelling. We also dissected Na+, K+ and Cl− requirements and found that unexpectedly low concentrations of each ion meet the parasite&#39;s demands. Surprisingly, growth was not adversely affected by up to 148 mM K+, suggesting that low e...

Assembly of the Bacillus subtilis spore coat involves over 80 protein components, which self-organize into a basal layer, a lamellar inner coat, a striated electrondense outer coat and a more external crust. CotB is an abundant component of the outer coat. Its C-terminal moiety contains a region, termed SKRB, formed by a series of serine-rich repeats, which we show is phosphorylated by the coat-associated Ser/Thr kinase CotH at multiple Ser residues. Another coat protein, CotG, which contains a central repeat region, SKRG, interacts with the C-terminal moiety of CotB and promotes its phosphorylation by CotH in vivo and in a heterologous system. CotG itself is phosphorylated by CotH but phosphorylation is enhanced in the absence of CotB. Spores of a cotHD288A strain, producing an inactive form of the kinase, like those formed by a cotG deletion mutant, lack the characteristic pattern of electrondense outer coat striations, while retaining the crust. Specifically, in the absence of Co...

Introduction: Carbapenems are the last resort drugs used to treat multidrug resistant (MDR) bacterial infections. The incidence of carbapenem resistance is increasing across the globe. Treatment failure and eventually high mortality were reported among individuals with carbapenem resistant bacterial infections. The incidence of carbapenemresistant Klebsiella pneumoniae (CRKP) infections is increasing globally. The blaNDM is the predominant carbapenemresistant gene in CRKP isolates. However, blaOXA-48 has also been reported to be increasing in recent days. Aim And Objective: To study the molecular characterization of blaNDM and blaOXA-48 gene in carbapenam resistant klebsiella isolates. Material And Methods: This was a Cross sectional study carried out in the Department of Microbiology for a period of 18 months i.e, November 2022 to May 2023. A total of 300 Klebsiella species from the isolates were tested collected from hospitalized and consultation patients were included in the study. The Antimicrobial susceptibility testing was performed according to the CLSI guidelines. The DNA extraction was done using the Qiagen DNA extraction kit and the resistant gene blaNDM and blaOXA-48 was detected using the PCR. Results: A total of 300 Klebsiella species from the isolates were tested out of which Carbapenamses resistant kKbspp was observed to be 204(68%) and Carbapenamses sensitive Kbspp with 96 (32%) with the prevalence rate of 68%. The ratio of females was observed to be more as compared to the males with 64% and 36% respectively with the age group of 30-40 (38.7%) been affected the most. The maximum isolates were from urine (55%) and least for body fluid with 3%. The Ratio of Male/Female amongst Carbapenamses resistant klebsiella isolates was observed to be 32.9% and 67.1 % respectively. The age group 30-40 was the most commonly affected in Carbapenamses resistant klebsiella isolates with the urine cases most commonly found with 51.4%. The molecular characterization confirms BLANDM gene 48 (23.5%) and BLAOXA-48 with 57 (27.9%) was expressed. Conclusion: CRKP is emerging as a serious threat among drug-resistant bacterial pathogens which would complicate the treatment of bacterial infections with available antibiotics. Performing regular surveillance studies in hospitals is very important to identify the circulating genes among carbapenem-resistant bacteria which will help to overcome the therapeutic challenges in treating the patients infected with CRKP.

The different morphological stages of Plasmodium falciparum show different physiological and biochemical characteristic. Lately there has been a renewed interest in the proteome of the parasite leading to considerable body of work towards identification of stage and sex specific proteins. In 2002 a whole chromosome shotgun sequencing of P falciparum clone 3D7 was completed. The chromosomes of P falciparum show gene clustering with coregulated gene groups and proteins. The Parasitophorous Vacuole Membrane and Gametocyte Exported Proteins are seen to be over expressed during early phase of sexual differentiation. The gametocyte proteome is in general specific to differing functionalities of the sexes. All ribosomal proteins are highly expressed in females. The sensitivity of this stage to antimalarials attacking respiration like primaquine and artemisinin based drugs is pronounced. Research on on NF54 isolate of P falciparum has revealed that of the total of 1289 proteins found by nan...

Candida albicans is an opportunistic yeast that can cause life-threatening systemic infection in immunocompromised individuals. During infections, C. albicans has to cope with genotoxic stresses generated by the host immune system. DNA-protein crosslink (DPC), the covalent linkage of proteins with DNA, is one type of DNA damages that can be caused by the host immune response. DPCs are bulky lesions that interfere with the progression of replication and transcription machineries, and hence threaten genomic integrity. Accordingly, either a DPC tolerance mechanism or a DPC repair pathway is essential for C. albicans to maintain genomic stability and survive in the host. Here, we identified Wss1 (weak suppressor of Smt3) in Candida albicans (CaWss1) using bioinformatics, genetic complementation, and biochemical studies. We showed that CaWss1 promotes cell survival under genotoxic stress conditions that generate DPCs, and that the catalytic metalloprotease domain of CaWss1 is essential for its cellular function. Interactions of CaWss1 with Cdc48 and small ubiquitin-like modifier (SUMO), although not strictly required, contribute to the function of CaWss1 in the suppression of the growth defects under DPC-inducing conditions. This report is the first investigation of the role of CaWss1 in DPC tolerance in C. albicans.

SummaryPeptidoglycan (PG), the major component of the bacterial cell wall, is one large macromolecule. To allow for the different curvatures of PG at cell poles and division sites, there must be local differences in PG architecture and eventually also chemistry. Here we report such local differences in the Gram‐positive rod‐shaped model organism Bacillus subtilis. Single‐cell analysis after antibiotic treatment and labeling of the cell wall with a fluorescent analogue of vancomycin or the fluorescent D‐amino acid analogue (FDAA) HCC‐amino‐D‐alanine revealed that PG at the septum contains muropeptides with unprocessed stem peptides (pentapeptides). Whereas these pentapeptides are normally shortened after incorporation into PG, this activity is reduced at division sites indicating either a lower local degree of PG crosslinking or a difference in PG composition, which could be a topological marker for other proteins. The pentapeptides remain partially unprocessed after division when th...

Myxococcus xanthus is a Gram-negative bacterium which has a complex iife cycle that includes development {fruiting body formation). The gene for myxobacterial haemaggiutinin, mbhA, is developmentaiiy regulated and highly expressed. In this report we show that the mbhA mRNA is exceptionally stable for a prokaryotic organism, exhibiting a chemicai half life (ti/2) of 150 min at 18 h of development. The mbhA mRNA was not stable in vegetatively growing cells nor was it stable when expressed in Escherichia coli. We have used site-directed mutagenesis of the mbhA gene to analyse some of the determinants which mediate the stability of the mbhA transcript. Sequences within the 3'-untranslated region (3'-UTR) were found to be crucial for mRNA stabiiity. This region of mRNA can potentially form an extremely stable stem-loop structure immediately adjacent to the translationai stop codon. A deietion within this region caused a 10-foid increase in the decay rate of the transcript. Furthermore, conditions which were associated with reduced mbhA translation or mutations that caused premature termination of translation drasticaiiy reduced mRNA stabiiity even in the presence of the wild type 3"-UTR. These results suggest that a significant aspect of mbhA mRNA stability involves a synergistic interaction of the translational machinery with sequence elements within the 3"-UTR.

Broad-host pathogens have adapted a lifestyle that enables them to survive and replicate in different environments. Mycobacterium marinum, a close relative of Mycobacterium tuberculosis, is such an intracellular pathogen that can infect, survive and replicate in phagocytic cells of vertebrates as well as protozoan species. Here, we employed transposon-directed insertion-site sequencing (TraDIS) of a large pool of M. marinum transposon mutants to determine which genes are required, advantageous or disadvantageous for survival and replication in phagocytic cells of different host species. We found a number of general virulence mechanisms relevant for all hosts, including the ESX-1 protein secretion system, biosynthesis of the polyketide lipid phthiocerol dimycocerosate (PDIM) and proteins involved in uptake and metabolism of cholesterol. In addition, we could identify the putative CpsA regulator as a new general virulence factor. Interestingly, our data also showed that M. marinum contains a large set of host-specific virulence determinants. For instance, the general virulence-associated ESX-1 system requires auxiliary proteins that play a crucial role in species-dependent infection. We show that the bacterial factors required for a successful infection of protozoan species frequently differ from those used for macrophages derived from vertebrates, indicating that broad-host range pathogens such as M. marinum contain different sets of virulence factors that are customized for specific hosts. Furthermore, these data also imply that although amoebae may be used as an experimental model to study host-pathogen interactions for intracellular pathogens, they do not fully manifest interactions with pathogens relevant for crossing species or even kingdom barriers.

The chromosome of Mycobacterium tuberculosis encodes five type VII secretion systems (ESX-1-ESX-5). While the role of the ESX-1 and ESX-3 systems in M. tuberculosis has been elucidated, predictions for the function of the ESX-5 system came from data obtained in Mycobacterium marinum, where it transports PPE and PE_PGRS proteins and modulates innate immune responses. To define the role of the ESX-5 system in M. tuberculosis, in this study, we have constructed five M. tuberculosis H37Rv ESX-5 knockout/deletion mutants, inactivating eccA(5) , eccD(5) , rv1794 and esxM genes or the ppe25-pe19 region. Whereas the Mtbrv1794ko displayed no obvious phenotype, the other four mutants showed defects in secretion of the ESX-5-encoded EsxN and PPE41, a representative member of the large PPE protein family. Strikingly, the MtbeccD(5) ko mutant also showed enhanced sensitivity to detergents and hydrophilic antibiotics. When the virulence of the five mutants was evaluated, the MtbeccD(5) ko and Mtb...

The oral microbiota, comprising a diverse array of microorganisms inhabiting the oral cavity, plays a crucial role in maintaining oral and systemic health. This review paper provides a comprehensive analysis of the intricate relationship between oral microbiota and human health, highlighting its pivotal role in the prevention and development of various diseases. Key topics covered include the composition and dynamics of oral microbiota, its interactions with the host immune system and its implications in the pathogenesis of oral diseases such as dental caries, periodontal diseases and oral cancer. Furthermore, the systemic effects of oral microbiota on conditions such as cardiovascular disease, diabetes and respiratory infections are discussed. Additionally, emerging research on the therapeutic potential of modulating oral microbiota through probiotics, prebiotics and other interventions is reviewed. This paper underscores the significance of understanding and maintaining oral microbial balance for health and disease prevention.

Differences in respiratory activity of Escherichia coli under various stress-induced environments has shown the ability of rpoS and bolA genes to respond in several stress conditions and adaptation, leading to an increase rate of oxygen uptake. The results have shown the rate of respiratory activity (defined in mg O 2 /g bacteria min -1 ) changed under various stress-induced conditions, i.e. heat shock, cold shock and oxidative stress. Sudden shifts from optimal growth conditions to stress-induced environments led to an increase of the oxygen uptake rate of E. coli in presence of rpoS and bolA genes.

Differences in respiratory activity of Escherichia coli under various stress-induced environments has shown the ability of rpoS and bolA genes to respond in several stress conditions and adaptation, leading to an increase rate of oxygen uptake. The results have shown the rate of respiratory activity (defined in mg O2/g bacteria min-1) changed under various stress-induced conditions, i.e. heat shock, cold shock and oxidative stress. Sudden shifts from optimal growth conditions to stress-induced environments led to an increase of the oxygen uptake rate of E. coli in presence of rpoS and bolA genes.

a history of prior heart valve damage. The ability to stimulate the activation of resting platelets and their subsequent aggregation is regarded as an important virulence factor of bacteria that cause IE. Clumping factor A is the dominant surface protein responsible for platelet activation by S. aureus cells in the stationary phase of growth. This study used Lactococcus lactis as a surrogate host to study the mechanism of ClfApromoted platelet activation. Expression of ClfA from a nisin-inducible promoter demonstrated that a minimum level of surface-expressed ClfA was required. Using platelets that were purified from plasma, the requirement for both bound fibrinogen and immunoglobulin was demonstrated. The immunoglobulin G (IgG) requirement is consistent with the potent inhibition of platelet activation by a monoclonal antibody specific for the platelet Fc g g g g RIIa receptor. Furthermore the IgG must contain antibodies specific for the ClfA A domain. A model is proposed whereby bacterial cells armed with a sufficient number of surface-bound fibrinogen molecules can engage resting platelet glycoprotein GPIIb/IIIa, aided by bound IgG molecules, which encourages the clustering of Fc g g g g RIIa receptors. This can trigger activation of signal transduction leading to activation of GPIIb/IIIa and aggregation of platelets. In addition, analysis of a mutant of ClfA totally lacking the ability to bind fibrinogen revealed a second, although less efficient, mechanism of platelet activation. The fibrinogen-independent pathway required IgG and complement deposition to trigger platelet aggregation

Several tools have been proposed for serodiagnosis of cystic echinococcosis (CE), but none appears promising for cyst viability assessment. Antigens with stage-specific diagnostic value have been described, but few studies with well-characterized antigens and human sera have been performed. Antigen B (AgB) proteoforms hold promise as markers of viability, due to their differential stage-related expression and immunoreactivity. Four AgB subunits (AgB1, AgB2, AgB3, AgB4) were synthesized and structurally characterized. Based on the preliminary evaluation of the subunits by western immunoblotting and ELISA, AgB1 and AgB2 were further tested in two ELISA setups, and extensively validated on 422 human sera. All subunits showed a high degree of spontaneous oligomerization. Interacting residues within oligomers were identified, showing that both N-Terminal and C-Terminal of each subunit are involved in homo-oligomer contact interfaces. No hetero-oligomer was identified. AgB1 and AgB2 ELISA...

Clinical diagnosis and follow up of cystic echinococcosis (CE) are based on imaging complemented by serology. Several immunodiagnostic tests are commercially available, but the development of new tools is still needed to overcome the lack of standardization of the target antigen, generally consisting of a crude extract of Echinococcus granulosus hydatid cyst fluid. In a previous work, we described a chromatographic method for the preparation of a highly enriched Antigen 5 fraction from hydatid cyst fluid. The high reactivity of patient sera against this preparation prompted us to evaluate further this antigen for the serodiagnosis of CE on a larger cohort of samples. A total of 327 sera from CE patients with heterogeneous conditions for cyst stage, cyst number, organ localization, drug therapy, and surgical intervention, together with 253 sera from healthy controls, were first analyzed by an ELISA based on the Ag5 preparation in two different experimental setups and, in parallel, by...