Petr Volf - Academia.edu (original) (raw)

Papers by Petr Volf

Acta Tropica, Mar 1, 2022

Cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis is the most widespread clinic... more Cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis is the most widespread clinical form of leishmaniasis in the Americas. Migonemyia migonei is a widely distributed phlebotomine sand fly species in Brazil and has been implicated as a vector for L. (V.) braziliensis. In the present study, we investigated the effects of salivary gland homogenates (SGH) of Mg. migonei on the course of L. (V.) braziliensis infection in BALB/c mice. Mice were separated into four groups (six mice per group): CRTL (uninfected mice); SGH (mice inoculated with Mg. migonei SGH); SGH+LEISH (mice inoculated with Mg. migonei SGH plus L. (V.) braziliensis promastigotes); LEISH (mice inoculated with L. (V.) braziliensis promastigotes). Mice were followed up for 8 weeks and the cellular immune response was evaluated by flow cytometry at the end of the experiment. Analysis of cytokine production by splenic cells stimulated with 0.5 SGH, 0.25 SGH of Mg. migonei or L. (V.) braziliensis soluble antigen stimulation (LSA) demonstrated that upon stimulation with SGH 0.25, the production of IL-17A and TNF was not sustained in the SGH group, with decreasing levels of these cytokines after 5 days compared to 3 days of incubation. Analyzing the production of cytokines after LSA stimulation, we observed lower levels of IL-17A in the SGH group after 5 days compared to 3 days. The same was observed for IFN-γ in the SGH group. Yet, the levels of TNF were significantly higher in the LEISH group after 5 days compared to 3 days. Among SGH+LEISH and LEISH mice, three animals in each group developed skin lesions on the tail, the mean lesion size was significantly higher in the LEISH group. Our study suggests that Mg. migonei SGH may modulate BALB/c immune response, as reflected by the low production or early decrease of pro-inflammatory cytokines in splenic cell cultures following stimulation with L. (V.) braziliensis antigen. Our data also suggest that Mg. migonei saliva may reduce the lesion size in BALB/c mice, but further research with a larger sample size is needed to confirm this hypothesis.

Journal of Medical Entomology, Nov 9, 2021

Parasites & Vectors, Oct 11, 2018

Frontiers in Cellular and Infection Microbiology, Aug 24, 2020

Parasites & Vectors, May 7, 2020

PLOS Genetics, Jan 16, 2014

The heatmap shows chromosomal copy number for all 36 chromosomes across the 12 CUK strai... more The heatmap shows chromosomal copy number for all 36 chromosomes across the 12 CUK strains, based on normalized chromosome read-depth. Copy number varies from disomic (light yellow) to pentasomic (dark-red).</p

Transboundary and Emerging Diseases

Antibodies against Phlebotomus perniciosus sand fly salivary gland homogenate (SGH) and recombina... more Antibodies against Phlebotomus perniciosus sand fly salivary gland homogenate (SGH) and recombinant protein rSP03B, sand fly-borne Toscana virus (TOSV), Sand Fly Fever Sicilian virus (SFSV) and Leishmania, as well as DNA of the latter parasite, were investigated in 670 blood samples from 575 human donors in Murcia Region, southeast Spain, in 2017 and 2018. The estimated SGH and rSP03B seroprevalences were 69% and 88%, respectively, although correlation between test results was relatively low (ρ = 0.39). Similarly, TOSV, SFSV and Leishmania seroprevalences were 26%, 0% and 1%, respectively, and Leishmania PCR prevalence was 2%. Prevalences were significantly greater in 2017, overdispersed and not spatially related to each other although both were positively associated with SGH but not to rSP03B antibody optical densities, questioning the value of the latter as a diagnostic marker for these infections in humans. This article is protected by copyright. All rights reserved.

BMC genomics, 2015

The phlebotomine sand fly Phlebotomus perniciosus (Diptera: Psychodidae, Phlebotominae) is a majo... more The phlebotomine sand fly Phlebotomus perniciosus (Diptera: Psychodidae, Phlebotominae) is a major Old World vector of the protozoan Leishmania infantum, the etiological agent of visceral and cutaneous leishmaniases in humans and dogs, a worldwide re-emerging diseases of great public health concern, affecting 101 countries. Despite the growing interest in the study of this sand fly species in the last years, the development of genomic resources has been limited so far. To increase the available sequence data for P. perniciosus and to start studying the molecular basis of the sexual differentiation in sand flies, we performed whole transcriptome Illumina RNA sequencing (RNA-seq) of adult males and females and de novo transcriptome assembly. We assembled 55,393 high quality transcripts, of which 29,292 were unique, starting from adult whole body male and female pools. 11,736 transcripts had at least one functional annotation, including full-length low abundance salivary transcripts, 9...

European Journal of Entomology, 2013

Sandfly females, while feeding on the host, excrete urine to concentrate proteins of the bloodmea... more Sandfly females, while feeding on the host, excrete urine to concentrate proteins of the bloodmeal and restore weight and water balance. This process, analogous to prediuresis in mosquitoes, was ob served in 100% of Phlebotomus papatasi (Scopoli) and 85% of P. duboscqi Neveu-Lemaire females studied. Individual females, however, differed in duration of prediuresis and in the number of ejected urine droplets. In both species the prediuresis generally started 1-2 min after the commencement of feed ing and the variation in urine production was positively correlated with the length of feeding. The first one or two droplets were opaque whitish while the remaining ones were clear. Erythrocytes were found sporadically in first droplets of some females. Representative prediuresis in P. duboscqi included 27 drop lets, i.e., about 325 nl urine in total, ejected during 8 min of feeding. The study revealed prediuresis in P. papatasi and P. duboscqi as a regular physiological process which may have consequences in transmis sion of infective diseases.

PLOS Neglected Tropical Diseases, 2012

The non MON-1 strains from Turkey as well as the Cyprian canine isolate clone 1 analysed... more The non MON-1 strains from Turkey as well as the Cyprian canine isolate clone 1 analysed herein are presented in bold.VL, visceral leishmaniasis; CL, cutaneous leishmaniasis; PKDL, post Kala Azar dermal leishmaniasis; CanL, canine leishmaniasis.*Only one of the three MON-37 clones (cl.1) isolated from the parent CD44 strain was further analyzed;**Hybrid strain; CY, Cyprus; ET, Ethiopia; GR, Greece; IN, India; KE, Kenya; LK, Sri Lanka; PT, Portugal; SD, Sudan; SP, Spain; TR, Turkey; n.d., not defined.</p

Parasites & Vectors, 2020

BackgroundSand flies are vectors ofLeishmaniaspp., the causative agents of leishmaniasis in verte... more BackgroundSand flies are vectors ofLeishmaniaspp., the causative agents of leishmaniasis in vertebrates, including man. The sand fly saliva contains powerful pharmacologically active substances that prevent hemostasis and enhanceLeishmaniaspp. infections. On the other hand, salivary proteins can protect vaccinated mice challenged with parasites. Therefore, sand fly salivary proteins are relevant for the epidemiology of leishmaniasis and can be a potential target for a vaccine against leishmaniasis. Despite this, studies on sand fly salivary glands (SGs) are limited.MethodsThe present study analyzes, in detail, the morphology, anatomy and ultrastructure of the SGs of sand fly vectors of the generaLutzomyiaandPhlebotomus. We used histology, transmission and scanning electron microscopy and lectin labeling associated with confocal laser microscopy.ResultsThe SGs have conserved and distinct morphological aspects according to the distinct sand fly species. Each SG has a single rounded lo...

Research Square (Research Square), Nov 11, 2020

Background: Phlebotomine sand ies are the principal vectors of Leishmania spp. (Kinetoplastida: T... more Background: Phlebotomine sand ies are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). Sand y ndings in Central Europe are scarce and in Austria, to date only Phlebotomus mascittii has been recorded. In 2018 and 2019, entomological surveys were conducted in Austria with the aim to further clarify sand y distribution and species composition. Results: In 2019, a Ph. simici specimen was trapped in Austria for the rst time. Analyses of two commonly used marker genes, coxI and cytb, revealed high sequence identity with Ph. simici specimens from North Macedonia and Greece. Phylogenetic analyses showed high intraspeci c distances within Ph. simici, thereby dividing this species into three lineages, from Europe, Turkey and Israel, respectively. Low interspeci c distances between Ph. simici, Ph. brevis and a yet unidenti ed Adlerius sp. from Turkey and Armenia highlights that molecular identi cation can be challenging within the Adlerius complex, even when applying standard marker genes. Conclusion: This study provides the rst nding of Ph. simici in Austria and the northernmost record so far. Moreover, it reveals valuable insights into the phylogenetic relationships of species within the Adlerius subgenus. Ph. simici is a suspected vector of Leishmania infantum and therefore of medical and veterinary importance. Potential sand y expansion in Central Europe due to climatic change and the increasing import of Leishmania-infected dogs from endemic areas, urge the need for further studies on sand y distribution in Austria and Central Europe in general.

PLOS Neglected Tropical Diseases, Sep 9, 2019

Background Identification of blood sources of hematophagous arthropods is crucial for understandi... more Background Identification of blood sources of hematophagous arthropods is crucial for understanding the transmission cycles of vector-borne diseases. Many different approaches towards host determination were proposed, including precipitin test, ELISA, DNA-and mass spectrometry-based methods; yet all face certain complications and limitations, mostly related to blood degradation. This study presents a novel method for blood meal identification, peptide mass mapping (PMM) analysis of host-specific hemoglobin peptides using MALDI-TOF mass spectrometry. Methodology/Principal findings To identify blood meal source, proteins from abdomens of engorged sand fly females were extracted, cleaved by trypsin and peptide fragments of host hemoglobin were sequenced using MALDI-TOF MS. The method provided correct host identification of 100% experimentally fed sand flies until 36h post blood meal (PBM) and for 80% samples even 48h PBM. In females fed on two hosts, both blood meal sources were correctly assigned for 60% of specimens until 36h PBM. In a validation study on field-collected females, the method yielded unambiguous host determination for 96% of specimens. The suitability of PMM-based MALDI-TOF MS was proven experimentally also on lab-reared Culex mosquitoes. Conclusions/Significance PMM-based MALDI-TOF MS analysis targeting host specific hemoglobin peptides represents a sensitive and cost-effective method with a fast and simple preparation protocol. As demonstrated here on phlebotomine sand flies and mosquitoes, it allows reliable and rapid blood source determination even 48h PBM with minimal material input and provides more robust and specific results than other currently used methods. This approach was also successfully tested on field-caught engorged females and proved to be a promising useful tool

Copyright information:Taken from "High degree of conservancy among secret... more Copyright information:Taken from "High degree of conservancy among secreted salivary gland proteins from two geographically distant sandflies populations (Mali and Kenya)"BMC Genomics 2006;7():226-226.Published online 4 Sep 2006PMCID:PMC1574310. (B) Sequence alignment of the orthologues PduK06 and PduM35; (C) PduK04 and PduM10. Black-shaded amino acids represent identical amino acids, grey-shaded amino acids represent conserved amino acids, and * at the top of the amino acids denotes potential T cell epitopes as searched by using the TEPITOPE software.

PLOS Neglected Tropical Diseases, Jun 14, 2011

We quantified Leishmania infantum parasites transmitted by natural vectors for the first time. Bo... more We quantified Leishmania infantum parasites transmitted by natural vectors for the first time. Both L. infantum strains studied, dermotropic CUK3 and viscerotropic IMT373, developed well in Phlebotomus perniciosus and Lutzomyia longipalpis. They produced heavy late-stage infection and colonized the stomodeal valve, which is a prerequisite for successful transmission. Infected sand fly females, and especially those that transmit parasites, feed significantly longer on the host (1.5-1.8 times) than non-transmitting females. Quantitative PCR revealed that P. perniciosus harboured more CUK3 strain parasites, while in L. longipalpis the intensity of infection was higher for the IMT373 strain. However, in both sand fly species the parasite load transmitted was higher for the strain with dermal tropism (CUK3). All but one sand fly female infected by the IMT373 strain transmitted less than 600 promastigotes; in contrast, 29% of L. longipalpis and 14% of P. perniciosus infected with the CUK3 strain transmitted more than 1000 parasites. The parasite number transmitted by individual sand flies ranged from 4 up to 4.19610 4 promastigotes; thus, the maximal natural dose found was still about 250 times lower than the experimental challenge dose used in previous studies. This finding emphasizes the importance of determining the natural infective dose for the development of an accurate experimental model useful for the evaluation of new drugs and vaccines.

PLOS Pathogens, Jan 17, 2017

A) Schematic representation of the cDNA16 locus and newly synthesised replacement constr... more A) Schematic representation of the cDNA16 locus and newly synthesised replacement constructs used. Flanking regions targeted for homologous recombination are indicated by dotted lines between top three panels and were the same for all constructs. The top row shows the cDNA16 locus as described by Flinn and Smith (1992); the second row describes the deletion constructs used by McKean et al. [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.ref031" target="_blank">31</a>] for the cDNA16 dKO line generation. Rows 3–8 show the HASP and SHERP replacement constructs used in this study for mutant generation. Refer to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.s001" target="_blank">S1</a> & <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.s002" target="_blank">S2</a> Figs for further details on replacement constructs and constructs integrated into the different mutant lines, respectively. Correct integration of NEO or BSD marker cassettes containing HASP and SHERP replacement constructs into the null background deleted either the HYG (hygromycin resistance gene) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.ref034" target="_blank">34</a>] or PAC (puromycin resistance gene) [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.ref035" target="_blank">35</a>] marker cassettes in cDNA16 dKO. The solid horizontal bars above the replacement constructs indicate the binding sites of the DIG-labelled Southern blot probes used in (B) below. SacI restriction at the sites shown generates the fragment sizes indicated below each construct, as detected in (B). B) Southern blots of SacI-digested gDNA from the selected mutant line clones (HASPA1 sKI (3), HASPA1/2 sKI (18), HASPA2 sKI (8), HASPB sKI (98), SHERP sKI (34), HA1/2+S2/HB sKI (4)) and the FVI and cDNA16 dKO controls. Data for the same clones are shown in the following figures unless indicated otherwise. The probes used on Southern blots are indicated in (A). Refer to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.s004" target="_blank">S4 Fig</a> for full set of blots.C) Quantitative PCR of gDNA from culture-derived parental (FVI) and mutant lines shown in (B) to determine construct copy number integration. For single copy integration, a value of 1(±0.2) was predicted, with the exception of the HASPA1/2 construct, containing two HASPA copies with identical ORFs, where a value of 2(±0.5) was expected. Refer to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.s005" target="_blank">S5 Fig</a> for complete analysis of tested clones.D) Immunoblot analysis of HASPA, HASPB and SHERP expression in culture-derived parental (FVI) and mutant lines (as in A) over a 7 day time course. The blots demonstrate stage specific expression of HASP and SHERP in the mutant lines; NMT is present as a loading control. For more details, refer to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.s006" target="_blank">S6</a> & <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.s007" target="_blank">S7</a> Figs.E) Growth assay in M199 culture of the parental (FVI) and mutant lines shown in (A). No significant growth defects due to genetic manipulation were observed in any of the mutant lines. Refer to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006130#ppat.1006130.s008" target="_blank">S8 Fig</a> for complete analysis of tested clones.</p

Nature Communications, Feb 23, 2021

Differentiation between distinct stages is fundamental for the life cycle of intracellular protoz... more Differentiation between distinct stages is fundamental for the life cycle of intracellular protozoan parasites and for transmission between hosts, requiring stringent spatial and temporal regulation. Here, we apply kinome-wide gene deletion and gene tagging in Leishmania mexicana promastigotes to define protein kinases with life cycle transition roles. Whilst 162 are dispensable, 44 protein kinase genes are refractory to deletion in promastigotes and are likely core genes required for parasite replication. Phenotyping of pooled gene deletion mutants using bar-seq and projection pursuit clustering reveal functional phenotypic groups of protein kinases involved in differentiation from metacyclic promastigote to amastigote, growth and survival in macrophages and mice, colonisation of the sand fly and motility. This unbiased interrogation of protein kinase function in Leishmania allows targeted investigation of organelle-associated signalling pathways required for successful intracellular parasitism.

Research Square (Research Square), Oct 8, 2020

Background Leishmaniasis, caused by parasites of the genus Leishmania, is a disease that effects ... more Background Leishmaniasis, caused by parasites of the genus Leishmania, is a disease that effects up to 8 million people worldwide. Parasites are transmitted to human and animal hosts through the bite of an infected sand y. Novel strategies for disease control, require a better understanding of the key step for transmission namely, the establishment of infection inside the y. Methods In this work we wanted to identify y systemic transcriptomic signatures associated with Leishmania infection. We used next generation sequencing to describe the transcriptome of whole Phlebotomus papatasi sand ies when fed with blood alone (control) or with blood containing one of three trypanosomatids: Leishmania major, Leishmania donovani and Herpetomonas muscarum: a parasite not transmitted to humans. Results Of these, only L. major is able to successfully establish an infection in P. papatasi. However, the transcriptional signatures observed after each parasite-contaminated blood meal were not speci c to success or failure of a speci c infection and were not different from each other. They were also indistinguishable from non-contaminated blood. Conclusions This implies that sand ies perceive Leishmania as just one feature of their microbiome landscape and that any strategy to tackle transmission should focus on the response towards the blood meal rather than parasite establishment. Alternatively, Leishmania could suppress host responses. These results will generate new thinking around the concept of stopping transmission by controlling the parasite inside the insect.