Publications

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molecular identification and genetic diversity among photorhabdus and xenorhabdus isolates.five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (galleria mellonella) infected with the entomopathogenic nematodes: heterorhabditis bacteriophora hp88, heterorhabditis indicus rm1 and heterorhabditis sp (s1), steinernema abbasi and steinernema sp. (s ii). strains were identified as photorhabdus luminescens hrm1, p. luminescens hs1, p. luminescens hp88, xenorhabdus indica and x. nematophila attc19061 using 16s rdna sequence analysis. to reveal the genetic div ...201728391470
modulation of behaviour and virulence of a high alginate expressing pseudomonas aeruginosa strain from cystic fibrosis by oral commensal bacterium streptococcus anginosus.cystic fibrosis (cf) airways harbour complex and dynamic polymicrobial communities that include many oral bacteria. despite increased knowledge of cf airway microbiomes the interaction between established cf pathogens and other resident microbes and resulting impact on disease progression is poorly understood. previous studies have demonstrated that oral commensal streptococci of the anginosus group (ags) can establish chronic pulmonary infections and become numerically dominant in cf sputa indi ...201728301571
identification of a pseudomonas aeruginosa pao1 dna methyltransferase, its targets, and physiological roles.dna methylation is widespread among prokaryotes, and most dna methylation reactions are catalyzed by adenine dna methyltransferases, which are part of restriction-modification (r-m) systems. r-m systems are known for their role in the defense against foreign dna; however, dna methyltransferases also play functional roles in gene regulation. in this study, we used single-molecule real-time (smrt) sequencing to uncover the genome-wide dna methylation pattern in the opportunistic pathogen pseudomon ...201728223461
manipulating virulence factor availability can have complex consequences for infections.given the rise of bacterial resistance against antibiotics, we urgently need alternative strategies to fight infections. some propose we should disarm rather than kill bacteria, through targeted disruption of their virulence factors. it is assumed that this approach (i) induces weak selection for resistance because it should only minimally impact bacterial fitness, and (ii) is specific, only interfering with the virulence factor in question. given that pathogenicity emerges from complex interact ...201728035238
efficacy of rifampicin combination therapy for the treatment of enterococcal infections assessed in vivo using a galleria mellonella infection model.enterococci are a leading cause of healthcare-associated infection worldwide and display increasing levels of resistance to many of the commonly used antimicrobials, making treatment of their infections challenging. combinations of antibiotics are occasionally employed to treat serious infections, allowing for the possibility of synergistic killing. the aim of this study was to evaluate the effects of different antibacterial combinations against enterococcal isolates using an in vitro approach a ...201728235571
combining two antifungal agents does not enhance survival of galleria mellonella larvae infected with madurella mycetomatis.to determine if combination therapy would improve therapeutic outcome in eumycetoma caused by madurella mycetomatis.201728342219
rnai-based functional genomics identifies new virulence determinants in mucormycosis.mucorales are an emerging group of human pathogens that are responsible for the lethal disease mucormycosis. unfortunately, functional studies on the genetic factors behind the virulence of these organisms are hampered by their limited genetic tractability, since they are reluctant to classical genetic tools like transposable elements or gene mapping. here, we describe an rnai-based functional genomic platform that allows the identification of new virulence factors through a forward genetic appr ...201728107502
virulent nontyphoidal salmonella producing ctx-m and cmy-2 β-lactamases from livestock, food and human infection, brazil. 201728102761
lepidopteran species have a variety of defence strategies against bacterial infections.the insect immune system has versatile ways of coping with microbial insults. currently, innate immune priming has been described in several invertebrates, and the first insights into its mechanistic basis have been described. here we studied infections with two different strains of serratia marcescens bacteria in two different lepidopteran hosts. the results reveal fundamental differences between the two hosts, a well-known model organism galleria mellonella and a non-model species arctia plant ...201728163013
the group a streptococcus serotype m2 pilus plays a role in host cell adhesion and immune evasion.group a streptococcus (gas), or streptococcus pyogenes, is a human pathogen that causes diseases ranging from skin and soft tissue infections to severe invasive diseases, such as toxic shock syndrome. each gas strain carries a particular pilus type encoded in the variable fibronectin-binding, collagen-binding, t antigen (fct) genomic region. here, we describe the functional analysis of the serotype m2 pilus encoded in the fct-6 region. we found that, in contrast to other investigated gas pili, t ...201727741558
heterologous expression of streptococcus mutans cnm in lactococcus lactis promotes intracellular invasion, adhesion to human cardiac tissues and virulence.in s. mutans, the expression of the surface glycoprotein cnm mediates binding to extracellular matrix proteins, endothelial cell invasion and virulence in the galleria mellonella invertebrate model. to further characterize cnm as a virulence factor, the cnm gene from s. mutans strain omz175 was expressed in the non-pathogenic lactococcus lactis nz9800 using a nisin-inducible system. despite the absence of the machinery necessary for cnm glycosylation, western blot and immunofluorescence microsco ...201727260618
discovery of a highly virulent strain of photorhabdus luminescens ssp. akhurstii from meghalaya, india.photorhabdus is an insect-pathogenic gram negative enterobacterium found in the gut of heterorhabditis nematodes. photorhabdus is highly virulent to insects, and can kill insects rapidly upon injection at very low concentrations of one to few cells. we characterized the virulence of photorhabdus symbionts isolated from the heterorhabditis nematodes collected from various parts of india by injecting different concentrations of bacterial cells into fourth instar larval stage of insect galleria mel ...201728148990
punica granatum l. (pomegranate) extract: in vivo study of antimicrobial activity against porphyromonas gingivalis in galleria mellonella model.due to the increase of bacterial resistance, medicinal alternatives are being explored. punica granatum l. is an effective herbal extract with broad spectrum of action and bactericidal, antifungal, anthelmintic potential and being able to modulate the immune response. the aim was to evaluate the antimicrobial activity of pomegranate glycolic extract (pge) against the periodontal pathogen porphyromonas gingivalis by using galleria mellonella as in vivo model. fifteen larvae were used per group. i ...201727668280
species diversity and population dynamics of entomopathogenic fungal species in the genus metarhizium-a spatiotemporal study.we studied the species diversity and population genetic structure of isolates of fungi from the entomopathogenic genus metarhizium that had been isolated from sugarcane crops and surrounding grass. soil and leaf samples were taken on four sampling occasions over 13 months (october 2014-october 2015). isolations were made using the galleria mellonella baiting method and selective media. phylogenetic placement of isolates was done by sequencing a fragment of the 5' of the elongation factor 1-α gen ...201728124726
requirement of the rna-binding protein smpb during intracellular growth of listeria monocytogenes.bacterial trans-translation is the main quality control mechanism employed to relieve stalled ribosomes. trans-translation is mediated by the small protein b (smpb) and transfer-mrna (tmrna) ribonucleoprotein complex, which interacts with translational complexes stalled at the 3' end of non-stop mrnas to release the stalled ribosomes thereby targeting the nascent polypeptides and truncated mrnas for degradation. the trans-translation system exists with a few exceptions in all bacteria. in the pr ...201728202229
novel cadmium resistance determinant in listeria monocytogenes.listeria monocytogenes is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. it is ubiquitous in the environment and often exhibits resistance to heavy metals. one of the determinants that enables listeria to tolerate exposure to cadmium is the cadac efflux system, with cada being a p-type atpase. three different cada genes (designated cada1 to cada3) were previously characterized in l. monocytogenes a novel putative cadmium resistance gene (cada4) was r ...201727986731
glycosylated metal chelators as anti-parasitic agents with tunable selectivity.trypanosoma cruzi and leishmania amazonensis are the causative agents of chagas' disease and leishmaniasis, respectively. these conditions affect millions of people worldwide, especially in developing countries. as such, there is an urgent need for novel, efficient and cost-effective treatments for these diseases, given the growing resistance and side-effects of current therapies. this work details the synthesis and evaluation of the anti-parasitic activity of novel amino- and iminopyridyl metal ...201728382355
alternative animal and non-animal models for drug discovery and development: bonus or burden?mammalian models have served as a basis for r&d over the past decades. nevertheless, these models are expensive, laborious, may yield results that cannot always be translated into the human in vivo situation and, more recently, have reverberated great social and ethical dilemmas. hence, the prospect of changes in the global scientific scenario and the three rs principle (reduction, replacement and refinement) have encouraged the development of alternative methods to the use of mammals. despite t ...201727858217
a novel restraint device for injection of galleria mellonella larvae that minimizes the risk of accidental operator needle stick injury.larvae of the insect galleria mellonella are increasingly being used for studying pathogenic microbes and their virulence mechanisms, and as a rapid model for screening novel antimicrobial agents. the larvae (waxworms) are most frequently infected by injection of pathogenic organisms into the haemocoel through the insect's prolegs. the mostly widely used method for restraining the waxworms for injection is by grasping them between the operator's fingers, which puts the operator at risk of needle ...201728401069
expression of the insect metalloproteinase inhibitor impi in the fat body of galleria mellonella exposed to infection with beauveria bassiana.the inducible metalloproteinase inhibitor (impi) discovered in galleria mellonella is currently the only specific inhibitor of metalloproteinases found in animals. its role is to inhibit the activity of metalloproteinases secreted by pathogenic organisms as virulence factors to degrade immune-relevant polypeptides of the infected host. this is a good example of an evolutionary arms race between the insect hosts and their natural pathogens. in this report, we analyze the expression of a gene enco ...201728399190
entomopathogenic nematodes in agricultural areas in brazil.entomopathogenic nematodes (epns) (steinernematidae and heterorhabditidae) can control pests due to the mutualistic association with bacteria that kill the host by septicemia and make the environment favorable for epns development and reproduction. the diversity of epns in brazilian soils requires further study. the identification of epns, adapted to environmental and climatic conditions of cultivated areas is important for sustainable pest suppression in integrated management programs in agricu ...201728382937
the galleria mellonella larvae as an in vivo model for evaluation of shigella virulence.shigella spp. causing bacterial diarrhea and dysentery are human enteroinvasive bacterial pathogens that are orally transmitted through contaminated food and water and cause bacillary dysentery. although natural shigella infections are restricted to humans and primates, several smaller animal models are used to analyze individual steps in pathogenesis. no animal model fully duplicates the human response and sustaining the models requires expensive animals, costly maintenance of animal facilities ...201728277944
a neuropeptide modulates sensory perception in the entomopathogenic nematode steinernema carpocapsae.entomopathogenic nematodes (epns) employ a sophisticated chemosensory apparatus to detect potential hosts. understanding the molecular basis of relevant host-finding behaviours could facilitate improved epn biocontrol approaches, and could lend insight to similar behaviours in economically important mammalian parasites. fmrfamide-like peptides are enriched and conserved across the phylum nematoda, and have been linked with motor and sensory function, including dispersal and aggregating behaviour ...201728253355
dna methyltransferases contribute to the fungal development, stress tolerance and virulence of the entomopathogenic fungus metarhizium robertsii.dna methylation is an important epigenetic mark in mammals, plants, and fungi and depends on multiple genetic pathways involving de novo and maintenance dna methyltransferases (dnmtases). metarhizium robertsii, a model system for investigating insect-fungus interactions, has been used as an environmentally friendly alternative to chemical insecticides. however, little is known concerning the molecular basis for dna methylation. here, we report on the roles of two dnmtases (mrrid and mrdim-2) by ...201728238081
analysis of the acute response of galleria mellonella larvae to potassium nitrate.potassium nitrate (e252) is widely used as a food preservative and has applications in the treatment of high blood pressure however high doses are carcinogenic. larvae of galleria mellonella were administered potassium nitrate to establish whether the acute effects in larvae correlated with those evident in mammals. intra-haemocoel injection of potassium nitrate resulted in a significant increase in the density of circulating haemocytes and a small change in the relative proportions of haemocyte ...201728232230
antimicrobial activity and interactions of cationic peptides derived from galleria mellonella cecropin d-like peptide with model membranes.antimicrobial peptides are effector molecules of the innate immune system against invading pathogens. the cationic charge in their structures has a strong correlation with antimicrobial activity, being responsible for the initial electrostatic interaction between peptides and the anionic microbial surface. this paper contains evidence that charge modification in the neutral peptide gm cecropin d-like (wt) improved the antimicrobial activity of the modified peptides. two cationic peptides derived ...201727999446
inhibition of eicosanoid signaling leads to increased lipid peroxidation in a host/parasitoid system.we posed the hypothesis that inhibition of eicosanoid biosynthesis leads to increased lipid peroxidation in insects. here we report that rearing the greater wax moth, galleria mellonella, on media supplemented with selected inhibitors of eicosanoid biosynthesis throughout the larval, pupal and adult life led to major alterations in selected oxidative and antioxidative parameters of wax moth and its ectoparasitoid, bracon hebetor. the highest dietary dexamethasone (dex), esculetin (esc) and pheni ...201727887946
functional investigation of iron-responsive microsomal proteins, including mirc, in aspergillus fumigatus.the functionality of many microsome-associated proteins which exhibit altered abundance in response to iron limitation in aspergillus fumigatus is unknown. here, we generate and characterize eight gene deletion strains, and of most significance reveal that mirc (afua_2g05730) contributes to the maintenance of intracellular siderophore [ferricrocin (fc)] levels, augments conidiation, confers protection against oxidative stress, exhibits an intracellular localization and contributes to fungal viru ...201728367141
the er-mitochondria encounter structure contributes to hyphal growth, mitochondrial morphology and virulence of the pathogenic mold aspergillus fumigatus.aspergillus fumigatus is an opportunistic fungal pathogen and the primary causative species of invasive aspergillosis, a systemic disease associated with high mortality rates. treatment of invasive fungal infection relies on a very limited number of antifungal drug classes. in order to extend the spectrum of antifungal drugs novel target structures have to be identified. the er-mitochondria encounter structure (ermes), a recently discovered tether that links mitochondria and endoplasmic reticulu ...201727939177
genome-wide transcriptome analysis of aspergillus fumigatus exposed to osmotic stress reveals regulators of osmotic and cell wall stresses that are saka(hog1) and mpkc dependent.invasive aspergillosis is predominantly caused by aspergillus fumigatus, and adaptations to stresses experienced within the human host are a prerequisite for the survival and virulence strategies of the pathogen. the central signal transduction pathway operating during hyperosmotic stress is the high osmolarity glycerol mitogen-activated protein kinase cascade. a. fumigatus mpkc and saka, orthologues of the saccharomyces cerevisiae hog1p, constitute the primary regulator of the hyperosmotic stre ...201727706915
1,2,4-triazolidine-3-thiones as narrow spectrum antibiotics against multidrug-resistant acinetobacter baumannii.with only two new classes of antibiotics developed in the last 40 years, novel antibiotics are desperately needed to combat the growing problem of multidrug-resistant and extensively drug resistant bacteria, particularly gram-negative bacteria. described in this letter is the synthesis and antibiotic activity of 1,2,4-triazolidine-3-thiones as narrow spectrum antibiotics. optimization of the 1,2,4-triazolidine-3-thione scaffold identified a small molecule with potent antibiotic activity against ...201728105270
modeling acinetobacter baumannii wound infections: the critical role of iron.acinetobacter baumannii has emerged as an increasingly important and successful opportunistic human pathogen due to its ability to withstand harsh environmental conditions, its characteristic virulence factors, and quick adaptability to stress.201728030490
repurposing the anticancer drug mitomycin c for the treatment of persistent acinetobacter baumannii infections.acinetobacter baumannii is an emergent opportunistic bacterial pathogen responsible for recalcitrant infections owing to its high intrinsic tolerance to most antibiotics; therefore, suitable strategies to treat these infections are needed. one plausible approach is the repurposing of drugs that are already in use. among them, anticancer drugs may be especially useful due their cytotoxic activities and ample similarities between bacterial infections and growing tumours. in this work, the effectiv ...201727939675
passive vectoring of entomopathogenic fungus beauveria bassiana among the wax moth galleria mellonella larvae by the ectoparasitoid habrobracon hebetor females.females of the ectoparasitoid habrobracon hebetor attack and envenomate numerous host individuals during oviposition. the vectoring of the entomopathogenic fungus beauveria bassiana during the adhesion stage by ectoparasitoid females among the wax moth larvae galleria mellonella was explored under laboratory conditions. vectoring occurred both from infected parasitoids to wax moth larvae and from infected to healthy wax moth larvae by parasitoids. the efficacy of vectoring in both cases was dose ...201728296161
additive roles of two tps genes in trehalose synthesis, conidiation, multiple stress responses and host infection of a fungal insect pathogen.intracellular trehalose accumulation is relevant to fungal life and pathogenicity. trehalose-6-phosphate synthase (tps) is known to control the first step of trehalose synthesis, but functions of multiple tps genes in some filamentous fungi are variable. here, we examined the functions of two tps genes (tpsa and tpsb) in beauveria bassiana, a fungal insect pathogen widely applied in arthropod pest control. intracellular tps activity and trehalose content decreased by 71-75 and 72-80% in δtpsa, a ...201728168316
studies on the virome of the entomopathogenic fungus beauveria bassiana reveal novel dsrna elements and mild hypervirulence.the entomopathogenic fungus beauveria bassiana has a wide host range and is used as a biocontrol agent against arthropod pests. mycoviruses have been described in phytopathogenic fungi while in entomopathogenic fungi their presence has been reported only rarely. here we show that 21.3% of a collection of b. bassiana isolates sourced from worldwide locations, harbor dsrna elements. molecular characterization of these elements revealed the prevalence of mycoviruses belonging to the partitiviridae ...201728114361
the pacc transcription factor regulates secondary metabolite production and stress response, but has only minor effects on virulence in the insect pathogenic fungus beauveria bassiana.the pacc transcription factor is an important component of the fungal ambient ph-responsive regulatory system. loss of pacc in the insect pathogenic fungus beauveria bassiana resulted in an alkaline ph-dependent decrease in growth and ph-dependent increased susceptibility to osmotic (salt, sorbitol) stress and sds. extreme susceptibility to congo red was noted irrespective of ph, and δbbpacc conidia showed subtle increases in uv susceptibility. the δbbpacc mutant showed a reduced ability to acid ...201728083986
effect of vacuolar atpase subunit h (vmah) on cellular ph, asexual cycle, stress tolerance and virulence in beauveria bassiana.vacuolar atpase (v-atpase) is a conserved multi-subunit protein complex that mediates intracellular acidification in fungi. here we show functional diversity of v-atpase subunit h (bbvmah) in beauveria bassiana, a filamentous fungal insect pathogen. deletion of bbvmah resulted in elevated vacuolar ph, increased ca(2+) level in cytosol but not in vacuoles, accelerated culture acidification and reduced accumulation of extracellular ammonia. aerial conidiation and submerged blastospore production w ...201728011319
evaluation of combination therapy for burkholderia cenocepacia lung infection in different in vitro and in vivo models.burkholderia cenocepacia is an opportunistic pathogen responsible for life-threatening infections in cystic fibrosis patients. b. cenocepacia is extremely resistant towards antibiotics and therapy is complicated by its ability to form biofilms. we investigated the efficacy of an alternative antimicrobial strategy for b. cenocepacia lung infections using in vitro and in vivo models. a screening of the nih clinical collection 1&2 was performed against b. cenocepacia biofilms formed in 96-well micr ...201728248999
the burkholderia cenocepacia peptidoglycan-associated lipoprotein is involved in epithelial cell attachment and elicitation of inflammation.the burkholderia cepacia complex (bcc) is a group of gram-negative opportunistic pathogens causing infections in people with cystic fibrosis (cf). bcc is highly antibiotic resistant, making conventional antibiotic treatment problematic. the identification of novel targets for anti-virulence therapies should improve therapeutic options for infected cf patients. we previously identified that the peptidoglycan-associated lipoprotein (pal) was immunogenic in bcc infected cf patients; however, its ro ...201727886433
the temperate burkholderia phage ap3 of the peduovirinae shows efficient antimicrobial activity against b. cenocepacia of the iiia lineage.burkholderia phage ap3 (vb_bcem_ap3) is a temperate virus of the myoviridae and the peduovirinae subfamily (p2likevirus genus). this phage specifically infects multidrug-resistant clinical burkholderia cenocepacia lineage iiia strains commonly isolated from cystic fibrosis patients. ap3 exhibits high pairwise nucleotide identity (61.7 %) to burkholderia phage ks5, specific to the same b. cenocepacia host, and has 46.7-49.5 % identity to phages infecting other species of burkholderia. the lysis c ...201727770178
temporal profile of biofilm formation, gene expression and virulence analysis in candida albicans strains.the characterization of candida albicans strains with different degrees of virulence became very useful to understand the mechanisms of fungal virulence. then, the objective of this study was to assess and compare the temporal profiles of biofilms formation, gene expression of als1, als3, hwp1, bcr1, efg1, tec1, sap5, plb2 and lip9 and virulence in galleria mellonella of c. albicans atcc18804 and a clinical sample isolated from an hiv-positive patient (ca60). although the cfu/ml counting was hig ...201727830437
lactobacillus rhamnosus inhibits candida albicans virulence factors in vitro and modulates immune system in galleria mellonella.the aim of this study was to evaluate the potential anti-candida effects of lactobacillus rhamnosus atcc 9595 on candida albicans atcc 18804 using in vitro and in vivo models.201727727499
effect of serine protease kex2 on candida albicans virulence under halogenated methyl sulfones.the effect of kex2 mutations on c. albicans virulence and resistance to halogenated methyl sulfones was assessed.201728287299
[galleria mellonella larva model in evaluating the effects of biofilm in candida albicans].biofilm-related infections are chronic infections that cause serious increase in morbidity and mortality as well as significant economic loss. galleria mellonella larva is shown as a reliable animal model for in vivo toxicology and pathogenicity tests due to its large size, ease of practice, ability to survive at 15-37°c and its similarity to mammals' natural immune system. the aim of this study was to evaluate the effects biofilm activity of candida albicans in a g.mellonella larva model. two c ...201728283008
candida albicans mycofilms support staphylococcus aureus colonization and enhances miconazole resistance in dual-species interactions.polymicrobial inter-kingdom biofilm infections represent a clinical management conundrum. the presence of co-isolation of bacteria and fungi complicates the ability to routinely administer single antimicrobial regimens, and synergy between the microorganisms influences infection severity. we therefore investigated the nosocomial pathogens staphylococcus aureus and candida albicans with respect to antimicrobial intervention. we characterized the interaction using biofilm assays and evaluated the ...201728280487
lactobacillus paracasei modulates the immune system of galleria mellonella and protects against candida albicans infection.probiotics have been described as a potential strategy to control opportunistic infections due to their ability to stimulate the immune system. using the non-vertebrate model host galleria mellonella, we evaluated whether clinical isolates of lactobacillus spp. are able to provide protection against candida albicans infection. among different strains of lactobacillus paracasei, lactobacillus rhamnosus and lactobacillus fermentum, we verified that l. paracasei 28.4 strain had the greatest ability ...201728267809
unexplored endemic fruit species from brazil: antibiofilm properties, insights into mode of action, and systemic toxicity of four eugenia spp.brazilian endemic fruit species have aroused attention due to their highly valuable, yet unexplored, agro-industrial, food and therapeutic potential. herein, we describe the antifungal activity of four eugenia spp. against candida albicans biofilms, and further demonstrate insights into their potential mode(s) of action and toxicity in vitro and in vivo. extracts from different parts (seeds, pulps, leaves) of e. leitonii (el), e. brasiliensis (eb), e. myrcianthes (em) and e. involucrata (ei) wer ...201728259673
effect of different wavelengths and dyes on candida albicans: in vivo study using galleria mellonella as an experimental model.studies on photodynamic inactivation against microorganisms had a great development in recent years. the aim of this work was to test the application of different laser wavelengths with or without different photosensitizing dyes on candida albicans cells in vitro and in photodynamic therapy protocols in vivo in larvae of galleria mellonella.201728130177
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