Strains Of Different Geographical Origin Research Articles

Lipopolysaccharide O-antigen profiles of Helicobacter pylori strains from Southwest China

BackgroundHelicobacter pylori lipopolysaccharide (LPS) structures vary among strains of different geographic origin. The aim of this study was to characterize the LPS O-antigen profiles of H. pylori strains isolated from Southwest China, and to further analyze the association of Lewis antigen expression with clinical outcomes and antibiotic resistance.ResultsA total of 71 H. pylori isolates from Southwest China were included for LPS profiling by silver staining and Western blotting after SDS-PAGE electrophoresis. We demonstrated that all the clinical isolates had the conserved lipid A and core-oligosaccharide, whereas the O-antigen domains varied significantly among the isolates. Compared with the common presence of the glucan/heptan moiety in LPS O-antigen structure of European strains, the clinical isolates in this study appeared to lack the glucan/heptan moiety. The expression frequency of Lex, Ley, Lea, and Leb was 66.2% (47/71), 84.5% (60/71), 56.3% (40/71), and 31.0% (22/71), respectively. In total, the expression of type II Lex and/or Ley was observed in 69 (97.2%) isolates, while type I Lea and/or Leb were expressed in 49 (69.0%) isolates. No association of Lewis antigen expression with clinical outcomes or with antibiotic resistance was observed.ConclusionsH. pylori strains from Southwest China tend to produce heptan-deficient LPS and are more likely to express type I Lewis antigens as compared with Western strains. This may suggest that H. pylori evolves to change its LPS structure for adaptation to different hosts.

Sequence Variability of pXO1-Located Pathogenicity Genes of Bacillus anthracis Natural Strains of Different Geographic Origin.

The main pathogenic factor of Bacillus anthracis is a three-component toxin encoded by the pagA, lef, and cya genes, which are located on the pXO1 plasmid. The atxA gene, which encodes the primary regulator of pathogenicity factor expression, is located on the same plasmid. In this work, we evaluated the polymorphism of the pagA, lef, cya, and atxA genes for 85 B. anthracis strains from different evolutionary lineages and canSNP groups. We have found a strong correlation of 19 genotypes with the main evolutionary lineages, but the correlation with the canSNP group of the strain was not as strong. We have detected several genetic markers indicating the geographical origin of the strains, for example, their source from the steppe zone of the former USSR. We also found that strains of the B.Br.001/002 group caused an anthrax epidemic in Russia in 2016 and strains isolated during paleontological excavations in the Russian Arctic have the same genotype as the strains of the B.Br.CNEVA group circulating in Central Europe. This data could testify in favor of the genetic relationship of these two groups of strains and hypothesize the ways of distribution of their ancestral forms between Europe and the Arctic.

Founder Effects Contribute to the Population Genetic Structure of the Major Dermatophytosis Pathogen Trichophyton rubrum on Hainan Island, China.

BackgroundFounder events have been observed among numerous plants and animal species living on oceanic islands due to the geographic separation of these islands and the small amount of original life they harbor. However, there has been little research on the ecological characteristics of pathogenic microorganisms on islands. Trichophyton rubrum ranks the most common isolated dermatophyte causing dermatophytosis in clinic and has become an epidemic strain worldwide in recent decades.ObjectiveTo study the phylogenetic characteristics and the distribution pattern of genetic polymorphism of T. rubrum in China, which further provide theoretical basis for the prevention and control of T. rubrum.MethodsIn the present study, we sequenced and analyzed the genetic characteristics of 204 T. rubrum isolates from Hainan Island and other sites in China. Phylogenetic analysis and genetic polymorphisms were studied based on a total of 41,409 high-quality whole-genome SNPs.ResultsThe majority of the isolates from Hainan Island clustered together. Mixed T. rubrum population differentiation was observed among the strains of different geographical origins. In addition, the genetic diversity (π) of the Hainan isolates was low and showed no significant difference from that of isolates from other sites.ConclusionThis study is the first to discuss general ecological and evolutionary principles related to pathogenic fungi. Our findings reveal a founder effect during the origination of T. rubrum on Hainan Island and provide guidance regarding prevention and treatment strategies.

Developmental plasticity among strains of the yellow mealworm,Tenebrio molitor L., under dry conditions

Edible insect production relies, among others, on the use of high-quality strains with good productivity characteristics. However, studies on the evaluation of the growth performance of different insect strains are limited. In this framework, the objective of the present study was to evaluate the growth and development under dry conditions of larvae of sixTenebrio molitor strains of different geographical origins, i.e. Greece, Italy, Turkey, Spain and USA, in terms of larval survival and development, as well as feed utilisation efficiency. In light of our results, we report the variable growth performance of differentT. molitor strains in the absence of a moisture source. Although no significant differences were shown among the strains tested with regard to the final larval weights and survival rates, there were significant differences in the development time and the growth rate, which may affect the overall efficiency ofT. molitor larvae production. Our study aims to highlight the significance of strain for the growth performance and consequently the productivity ofT. molitor.

Strain matters: strain effect on the larval growth and performance of the yellow mealworm,Tenebrio molitor L.

Much research has been directed towards the optimisation of the mass rearing of the yellow mealworm,Tenebrio molitor, in terms of diet and rearing conditions. However, an issue that has not been thoroughly investigated to date is the strain effect on the larval growth and performance ofT. molitor. To close this gap, the plasticity in growth and development, as well as the feed conversion efficiency and the nutritional composition of larvae of sevenT. molitor strains of different geographic origins (Greece, Italy, Germany, Turkey, Spain and USA) were comparatively evaluated in the present study. Based on the results, there were considerable differences in the performance of the strains tested. Larval weight at harvest was the highest for a strain originated from Germany; however, the higher final body mass was at the cost of longer development time and higher feed intake, the latter having a negative impact in the overall performance and productivity of the strain. No significant differences were detected in the larval nitrogen and lipid content among the strains tested. In overall, the Italian strain II had the best growth performance in terms of survival, larval biomass production, development time and feed utilisation. The present study aims to highlight the need for selection of strains with enhanced performance and production traits for mass-production, which will boost the overall productivity of insect farming systems.

Molecular, morphological and pathogenic characterization of Clavibacter michiganensis subsp. sepedonicus strains of different geographic origins in Georgia

Potato ring rot and its causative pathogen Clavibacter michiganensis subsp. sepedonicus (Cms) have been studied in Georgia for the first time. The samples were collected in the fields and potato storage facilities in various potato producing regions of Georgia. Potato tubers were also collected at agrarian markets and the border checkpoints, from which potatoes are imported from neighboring countries. In 124 potato samples the detection of Cms was performed using specific PCR analysis and bioassay test. A total of 20 Cms isolates were purified and identified by subspecies-specific PSA-1 and PSA-R primers set. The isolates were characterized according to cell morphology, cultural-biochemical properties and virulence. The study of genetic diversity using molecular typing methods of PCR melting profile with different restriction enzymes and variable number tandem repeats PCR revealed significant differences between Cms isolates, which is not related to their geographical origin.

Sources, Spectrum, Genetics, and Inheritance of Phaseolus vulgaris Resistance Against Xanthomonas citri pv. fuscans.

Common bean (Phaseolus vulgaris) is one of the most consumed agricultural products in the world. Its production is affected by common bacterial blight (CBB) caused by Xanthomonas citri pv. fuscans and X. phaseoli pv. phaseoli. In this work, we investigated the spectrum, genetics, and inheritance of common bean resistance to X. citri pv. fuscans. Inoculation of nine selected cultivars with an X. citri pv. fuscans strain showed that BRS Radiante and IAPAR 16 were resistant. These two cultivars were also resistant to six X. phaseoli pv. phaseoli strains of different geographic origins, demonstrating their broad-spectrum resistances. BRS Radiante sustained smaller X. citri pv. fuscans populations than two susceptible cultivars. Stomatal densities of IAPAR 16 and BRS Radiante were significantly higher than or not different from susceptible cultivars. BRS Radiante showed the lowest general combining ability values and the combination BRS Radiante × Carioca MG the lowest specific combining ability (SCA) values, revealing the capacity of BRS Radiante to increase resistance to X. citri pv. fuscans. Positive and negative parental SCA values indicated dominant and recessive genes involved in X. citri pv. fuscans resistance. Resistance of the BRS Radiante × Carioca MG cross segregated in a 9:7 ratio in the F2 population, indicating that it is governed by two complementary dominant genes. Maximum likelihood analysis showed that the resistance of BRS Radiante to X. citri pv. fuscans is conferred by a gene of major effect with contribution of additional polygenes. This study contributes with important knowledge on the resistance against CBB in Brazilian common bean cultivars as well as with molecular tools for confirmation of common bean hybrids.

Transcriptome analysis of Drosophila melanogaster laboratory strains of different geographical origin after long-term laboratory maintenance.

Positive selection may be the main factor of the between‐population divergence in gene expression. Expression profiles of two Drosophila melanogaster laboratory strains of different geographical origin and long‐term laboratory maintenance were analyzed using microchip arrays encompassing probes for 18,500 transcripts. The Russian strain D18 and the North American strain Canton‐S were compared. A set of 223 known or putative genes demonstrated significant changes in expression levels between these strains. Differentially expressed genes (DEG) were enriched in response to DDT (p = .0014), proteolysis (p = 2.285E−5), transmembrane transport (p = 1.03E−4), carbohydrate metabolic process (p = .0317), protein homotetramerization (p = .0444), and antibacterial humoral response (p = 425E−4). The expression in subset of genes from different categories was verified by qRT‐PCR. Analysis of transcript abundance between Canton‐S and D18 strains allowed to select several genes to estimate their participation in latitude adaptation. Expression of selected genes was analyzed in five D. melanogaster lines of different geographic origins by qRT‐PCR, and we found two candidate genes that may be associated with latitude adaptation in adult flies—smp‐30 and Cda9. Quite possible that several alleles of these genes may be important for insect survival in the environments of global warming. It is interesting that the number of genes involved in local adaptation demonstrates expression level appropriate to their geographical origin even after decades of laboratory maintenance.

Detection of Coxiella burnetii in ticks collected from cattle in several provinces of the Republic of Guinea

Background. Q fever, or coxiellosis, is a natural focal disease characterized by polymorphism of clinical signs and can affect not only humans but also many species of animals. This infection is spread almost all over the world. On the African continent, the foci of coxiellosis infection endanger the local population and people arriving for temporary stay. Given that sick agricultural animals and their ectoparasites are markers of the presence of infection in the region, a study of the latter may be relevant to identify the potential foci of Q fever.
 This work aimed to identify Coxiella burnetii DNA from ixodic ticks collected from cattle in several provinces of Republic of Guinea and to type isolates using genetic markers (plasmid type) to enable their comparison with strains of different geographical origin.
 Methods. Using amplification technologies, we investigated the ticks obtained from cattle in the provinces of Boke and Kindia to detect Coxiella DNA.
 Results. The genetic material of the Q fever causative agent was detected in no more than 5% of the total number of samples studied. For positive samples, typing was performed using plasmid analysis. The isolates with the plasmid type QpH1 circulate in the Republic of Guinea.
 Conclusion. The findings were analyzed along with data from other researchers on the spread of Q fever in subequatorial Africa. The differences in the levels of prevalence of Coxiella in ticks in the territories of not only different countries but also within the same state can be determined by the prevalence among the hosts within herds. The risk of contamination with Q fever in endemic regions should be considered.

Identifying geographic origins of the Escherichia coli isolates from food by a method based on single-nucleotide polymorphisms

BackgroundE.coli is an important foodborne pathogen. Rapid and robust tracking of the source of E. coli is the key step to control foodborne infections. ResultsIn this study, a genotyping and tracing method based on highly discriminatory single nucleotide polymorphisms (SNPs) was developed to investigate the geographical origin of E. coli in food. A highly informative set of 12 SNPs was derived from 4 housekeeping genes in E. coli multilocus sequence typing (MLST) database. A collection of 253 E. coli isolates from food in 12 countries and regions were screened, resulting in a total of 61 profiles, 35 geographically specific SNP profiles were revealed and further verified by blind sample test. Also, the evolutionary relationship of 61 SNP profiles with different geographical origins was established by the enhanced analysis Based Upon Related Sequence Types (eBURST) analysis, which provided evidence that strains of different geographical origins owned the same ancestor strain. ConclusionsOur study established a powerful method based on a set of 12 SNPs for identifying geographical origins. The blind sample analysis proved that this SNPs panel had a high traceability of E. coli in food. Furthermore, this method based on SNPs combined with eBURST analysis revealed the potential evolutionary relationship between E.coli strains of different geographical origins.

Mechanisms of iron sensing and regulation in the yeast Saccharomyces cerevisiae.

Iron is a redox active element that functions as an essential cofactor in multiple metabolic pathways, including respiration, DNA synthesis and translation. While indispensable for eukaryotic life, excess iron can lead to oxidative damage of macromolecules. Therefore, living organisms have developed sophisticated strategies to optimally regulate iron acquisition, storage and utilization in response to fluctuations in environmental iron bioavailability. In the yeast Saccharomyces cerevisiae, transcription factors Aft1/Aft2 and Yap5 regulate iron metabolism in response to low and high iron levels, respectively. In addition to producing and assembling iron cofactors, mitochondrial iron-sulfur (Fe/S) cluster biogenesis has emerged as a central player in iron sensing. A mitochondrial signal derived from Fe/S synthesis is exported and converted into an Fe/S cluster that interacts directly with Aft1/Aft2 and Yap5 proteins to regulate their transcriptional function. Various conserved proteins, such as ABC mitochondrial transporter Atm1 and, for Aft1/Aft2, monothiol glutaredoxins Grx3 and Grx4 are implicated in this iron-signaling pathway. The analysis of a wide range of S. cerevisiae strains of different geographical origins and sources has shown that yeast strains adapted to high iron display growth defects under iron-deficient conditions, and highlighted connections that exist in the response to both opposite conditions. Changes in iron accumulation and gene expression profiles suggest differences in the regulation of iron homeostasis genes.

Comparison of antioxidant capacities of two Ganoderma lucidum strains of different geographical origins

Ganoderma lucidum, used in a traditional Chinese medicine, represents one of the most important medicinal mushrooms in the world, whose fruiting bodies and spores have been traditionally used because of a wide spectrum of biological activities such as antidiabetic, antioxidative, antiproliferative, cardioprotective, etc. Its ethnomedicinal importance in some parts of the Balkan region (Serbia and Croatia) is almost totally unknown and there should be more scientific investigations carried out. The aim of this work was to make a comparative study of antioxidative activities and total phenolic content of ethanol and hot water extracts of G. lucidum, collected from forests in Serbia (Morovicke sume, Fruska Gora) and Croatia (Donji Lapac, Pljesevica). The present study was carried out to evaluate antioxidant potential of examined extracts via scavenging potential on ABTS, DPPH, OH? and NO? radicals, as well as of chelating effects via FRAP assay, together with determination of their total phenolic content. Results showed that both GLS extracts possessed better antiradical activities (IC50=0.23?0.01 for H2O and 2.75?0.01 ?g/mL for EtOH for OH? and DPPH assay, respectively) than in the ABTS assay (151.40?1.07 mg TE/g d.w. for EtOH), while the phenolic content was generally equal in extracts of Serbian and Croatian samples (60.74?0.57 mg GAE/g d.w. for EtOH and 77.10?0.27 mg GAE/g d.w. for H2O, respectively). Therefore, these extracts could be considered as a good source of natural antioxidants. These results showed that examined G. lucidum extracts (especially ?2?) contain high amount of phenolic content which could significantly enhance the antiradical potential and reduce potential on iron ions. This is the first study reporting the comparison of antioxidant activities and phenolic contents of two different extracts between two G. lucidum strains from two different geographical origins from the Balkan region.

Genome of Leptomonas pyrrhocoris: a high-quality reference for monoxenous trypanosomatids and new insights into evolution of Leishmania.

Many high-quality genomes are available for dixenous (two hosts) trypanosomatid species of the genera Trypanosoma, Leishmania, and Phytomonas, but only fragmentary information is available for monoxenous (single-host) trypanosomatids. In trypanosomatids, monoxeny is ancestral to dixeny, thus it is anticipated that the genome sequences of the key monoxenous parasites will be instrumental for both understanding the origin of parasitism and the evolution of dixeny. Here, we present a high-quality genome for Leptomonas pyrrhocoris, which is closely related to the dixenous genus Leishmania. The L. pyrrhocoris genome (30.4 Mbp in 60 scaffolds) encodes 10,148 genes. Using the L. pyrrhocoris genome, we pinpointed genes gained in Leishmania. Among those genes, 20 genes with unknown function had expression patterns in the Leishmania mexicana life cycle suggesting their involvement in virulence. By combining differential expression data for L. mexicana, L. major and Leptomonas seymouri, we have identified several additional proteins potentially involved in virulence, including SpoU methylase and U3 small nucleolar ribonucleoprotein IMP3. The population genetics of L. pyrrhocoris was also addressed by sequencing thirteen strains of different geographic origin, allowing the identification of 1,318 genes under positive selection. This set of genes was significantly enriched in components of the cytoskeleton and the flagellum.

Direct evidence of recombination in the recA gene of Aeromonas bestiarum

Two hundred and twenty-one strains representative of all Aeromonas species were characterized using the recA gene sequence, assessing its potential as a molecular marker for the genus Aeromonas. The inter-species distance values obtained demonstrated that recA has a high discriminatory power. Phylogenetic analysis, based on full-length gene nucleotide sequences, revealed a robust topology with clearly separated clusters for each species. The maximum likelihood tree showed the Aeromonas bestiarum strains in a well-defined cluster, containing a subset of four strains of different geographical origins in a deep internal branch. Data analysis provided strong evidence of recombination at the end of the recA sequences in these four strains. Intergenomic recombination corresponding to partial regions of the two adjacent genes recA and recX (248bp) was identified between A. bestiarum (major parent) and Aeromonas eucrenophila (minor parent). The low number of recombinant strains detected (1.8%) suggests that horizontal flow between recA sequences is relatively uncommon in this genus. Moreover, only a few nucleotide differences were detected among these fragments, indicating that recombination has occurred recently. Finally, we also determined if the recombinant fragment could have influenced the structure and basic functions of the RecA protein, comparing models reconstructed from the translated amino acid sequences of our A. bestiarum strains with known Escherichia coli RecA structures.

Genome Variations Associated with Viral Susceptibility and Calcification in Emiliania huxleyi

Emiliania huxleyi, a key player in the global carbon cycle is one of the best studied coccolithophores with respect to biogeochemical cycles, climatology, and host-virus interactions. Strains of E. huxleyi show phenotypic plasticity regarding growth behaviour, light-response, calcification, acidification, and virus susceptibility. This phenomenon is likely a consequence of genomic differences, or transcriptomic responses, to environmental conditions or threats such as viral infections. We used an E. huxleyi genome microarray based on the sequenced strain CCMP1516 (reference strain) to perform comparative genomic hybridizations (CGH) of 16 E. huxleyi strains of different geographic origin. We investigated the genomic diversity and plasticity and focused on the identification of genes related to virus susceptibility and coccolith production (calcification). Among the tested 31940 gene models a core genome of 14628 genes was identified by hybridization among 16 E. huxleyi strains. 224 probes were characterized as specific for the reference strain CCMP1516. Compared to the sequenced E. huxleyi strain CCMP1516 variation in gene content of up to 30 percent among strains was observed. Comparison of core and non-core transcripts sets in terms of annotated functions reveals a broad, almost equal functional coverage over all KOG-categories of both transcript sets within the whole annotated genome. Within the variable (non-core) genome we identified genes associated with virus susceptibility and calcification. Genes associated with virus susceptibility include a Bax inhibitor-1 protein, three LRR receptor-like protein kinases, and mitogen-activated protein kinase. Our list of transcripts associated with coccolith production will stimulate further research, e.g. by genetic manipulation. In particular, the V-type proton ATPase 16 kDa proteolipid subunit is proposed to be a plausible target gene for further calcification studies.

Clostridium difficile Genotypes in Piglet Populations in Germany

Clostridium difficile was isolated from 147 of 201 (73%) rectal swabs of piglets from 15 farms of Lower Saxony and North Rhine-Westphalia. In 14 farms, 14 to 100% (mean, 78%) of the animals tested were culture positive. The rate of isolation was 68% postpartum, increased to 94% in animals 2 to 14 days of age, and declined to 0% for animals 49 days of age and older. There was no link between isolation and antibiotic treatment or diarrhea of piglets. Strains were assigned to 10 PCR ribotypes, and up to 4 PCR ribotypes were found to be present at the same time on a farm. The closely related PCR ribotypes 078 (55%) and 126 (20%) were most frequently recovered and were present in 13 of the 14 positive farms. The comparison of multilocus VNTR (variable number of tandem repeats) analysis (MLVA) data from this study and previously published data on human, porcine, and bovine PCR ribotype 078 isolates from 5 European countries revealed genetic differences between strains of different geographic origin and confirmed the relatedness of human and porcine C. difficile isolates. This study demonstrated that the human-pathogenic PCR ribotypes 078 and 126 are predominant in piglets in Germany. The results suggest that presence of C. difficile is correlated with animal age but not with antibiotic treatment or clinical disease. MLVA indicated that strains of the same geographical origin are often genetically related and corroborated the hypothesis of a close epidemiological connection between human and porcine C. difficile isolates.

Female biased sex-ratio in Schistosoma mansoni after exposure to an allopatric intermediate host strain of Biomphalaria glabrata

For parasites that require multiple hosts to complete their development, the interaction with the intermediate host may have an impact on parasite transmission and development in the definitive host. The human parasite Schistosoma mansoni needs two different hosts to complete its life cycle: the freshwater snail Biomphalaria glabrata (in South America) as intermediate host and a human or rodents as final host. To investigate the influence of the host environment on life history traits in the absence of selection, we performed experimental infections of two B. glabrata strains of different geographic origin with the same clonal population of S. mansoni. One B. glabrata strain is the sympatric host and the other one the allopatric host. We measured prevalence in the snail, the cercarial infectivity, sex-ratio, immunopathology in the final host and microsatellite frequencies of individual larvae in three successive generations.We show that, even if the parasite population is clonal based on neutral markers, S. mansoni keeps the capacity of generating phenotypic plasticity and/or variability for different life history traits when confront to an unusual environment, in this study the intermediate host. The most dramatic change was observed in sex-ratio: in average 1.7 times more female cercariae were produced when the parasite developed in an allopatric intermediate host.

Toxin Levels and Profiles in Microalgae from the North-Western Adriatic Sea—15 Years of Studies on Cultured Species

The Northern Adriatic Sea is the area of the Mediterranean Sea where eutrophication and episodes related to harmful algae have occurred most frequently since the 1970s. In this area, which is highly exploited for mollusk farming, the first occurrence of human intoxication due to shellfish consumption occurred in 1989, nearly 10 years later than other countries in Europe and worldwide that had faced similar problems. Until 1997, Adriatic mollusks had been found to be contaminated mostly by diarrhetic shellfish poisoning toxins (i.e., okadaic acid and dinophysistoxins) that, along with paralytic shellfish poisoning toxins (i.e., saxitoxins), constitute the most common marine biotoxins. Only once, in 1994, a toxic outbreak was related to the occurrence of paralytic shellfish poisoning toxins in the Adriatic coastal waters. Moreover, in the past 15 years, the Adriatic Sea has been characterized by the presence of toxic or potentially toxic algae, not highly widespread outside Europe, such as species producing yessotoxins (i.e., Protoceratium reticulatum, Gonyaulax spinifera and Lingulodinium polyedrum), recurrent blooms of the potentially ichthyotoxic species Fibrocapsa japonica and, recently, by blooms of palytoxin-like producing species of the Ostreopsis genus. This review is aimed at integrating monitoring data on toxin spectra and levels in mussels farmed along the coast of the Emilia-Romagna region with laboratory studies performed on the species involved in the production of those toxins; toxicity studies on toxic or potentially toxic species that have recently appeared in this area are also reviewed. Overall, reviewed data are related to: (i) the yessotoxins producing species P. reticulatum, G. spinifera and L. polyedrum, highlighting genetic and toxic characteristics; (ii) Adriatic strains of Alexandrium minutum, Alexandrium ostenfeldii and Prorocentrum lima whose toxic profiles are compared with those of strains of different geographic origins; (iii) F. japonica and Ostreopsis cf. ovata toxicity. Moreover, new data concerning domoic acid production by a Pseudo-nitzschia multistriata strain, toxicity investigations on a Prorocentrum cf. levis, and on presumably ichthyotoxic species, Heterosigma akashiwo and Chattonella cf. subsalsa, are also reported.

Novel DNA markers for taxonomic characterization and identification of Fusarium species

RAPD analysis for ten F. sporotrichioides strains of different geographical origin was done for DNA loci, potentially suitable as a new markers for taxonomic characterization and identification of toxigenic Fusarium fungi. Three selected monomorphic fragments--products of amplification with one of standard RAPD primers were sequenced that allowed creating SCAR markers for identification of Fusarium fungi on the species group level with similar profiles of produced mycotoxins.

Phylogeny of Leishmania species based on the heat-shock protein 70 gene

The 70kDa heat-shock protein (HSP70) is conserved across prokaryotes and eukaryotes, and the protein as well as its encoding gene have been applied in phylogenetic studies of different parasites. In spite of the frequent use of New World Leishmania species identification on the basis of restriction fragment length polymorphisms (RFLP) in the hsp70 gene, it was never sequenced extensively for studying evolutionary relationships. To fill this void we determined the nucleotide sequence of an 1380bp fragment of the coding region commonly used in RFLP analysis, from 43 isolates and strains of different geographic origins. Combination with previously determined sequences amounted to a phylogenetic analysis including 52 hsp70 sequences representing 17 species commonly causing leishmaniasis both in the New and Old World. The genus Leishmania formed a monophyletic group with three distinct subgenera L. (Leishmania), L. (Viannia), and L. (Sauroleishmania). The obtained phylogeny supports the following eight species: L. (L.) donovani, L. (L.) major, L. (L.) tropica, L. (L.) mexicana, L. (V.) lainsoni, L. (V.) naiffi, L. (V.) guyanensis and L. (V.) braziliensis, in some of which subspecies can be recognized: L. (L.) donovani infantum, L. (V.) guyanensis panamensis, and L. (V.) braziliensis peruviana. The currently recognized L. (L.) aethiopica, L. (L.) garnhami, and L. (L.) amazonensis did not form monophyletic clusters. These findings are discussed in relation to results from other genes and proteins, which have to be integrated in order to build a genetically supported taxonomy for the entire genus.