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Current Opinion in Microbiology Aug 2016Maintenance of genome integrity is essential. However, programmed DNA elimination removes specific DNA sequences from the genome during development. DNA elimination... (Review)
Review
Maintenance of genome integrity is essential. However, programmed DNA elimination removes specific DNA sequences from the genome during development. DNA elimination occurs in unicellular ciliates and diverse metazoa ranging from nematodes to vertebrates. Two distinct groups of nematodes use DNA elimination to silence germline-expressed genes in the soma (ascarids) or for sex determination (Strongyloides spp.). Data suggest that DNA elimination likely evolved independently in these nematodes. Recent studies indicate that differential CENP-A deposition within chromosomes defines which sequences are retained and lost during Ascaris DNA elimination. Additional studies are needed to determine the distribution, functions, and mechanisms of DNA elimination in nematodes.
Topics: Animals; Ascaris; Base Sequence; Centromere Protein A; DNA, Protozoan; Female; Gene Silencing; Male; Sequence Deletion; Sex Determination Processes; Strongyloides
PubMed: 27315434
DOI: 10.1016/j.mib.2016.05.012 -
α-Gal specific-IgE prevalence and levels in Ecuador and Kenya: Relation to diet, parasites, and IgG.The Journal of Allergy and Clinical... Apr 2021IgE to α-Gal is a cause of mammalian meat allergy and has been linked to tick bites in North America, Australia, and Eurasia. Reports from the developing world indicate... (Comparative Study)
Comparative Study
BACKGROUND
IgE to α-Gal is a cause of mammalian meat allergy and has been linked to tick bites in North America, Australia, and Eurasia. Reports from the developing world indicate that α-Gal sensitization is prevalent but has been little investigated.
OBJECTIVE
We sought evidence for the cause(s) of α-Gal sensitization and lack of reported meat allergy among children in less developed settings in Ecuador and Kenya.
METHODS
IgE to α-Gal and total IgE were assessed in children from Ecuador (n = 599) and Kenya (n = 254) and compared with children with (n = 42) and without known (n = 63) mammalian meat allergy from the southeastern United States. Information on diet, potential risk factors, and helminth infections was available for children from Ecuador. IgG to α-Gal and antibodies to regionally representative parasites were assessed in a subset of children.
RESULTS
In Ecuador (32%) and Kenya (54%), α-Gal specific IgE was prevalent, but levels were lower than in children with meat allergy from the United States. Sensitization was associated with rural living, antibody markers of Ascaris exposure, and total IgE, but not active infections with Ascaris or Trichuris species. In Ecuador, 87.5% reported consuming beef at least once per week, including 83.9% of those who had α-Gal specific IgE. Levels of α-Gal specific IgG were not high in Ecuador, but were greater than in children from the United States.
CONCLUSIONS
These results suggest that in areas of the developing world with endemic parasitism, α-Gal sensitization is (1) common, (2) associated with Ascaris exposure, and (3) distinguished by a low percentage of specific/total IgE compared with individuals with meat allergy in the United States.
Topics: Adolescent; Adult; Animals; Ascaris; Child; Child, Preschool; Diet; Disaccharides; Ecuador; Feces; Female; Food Hypersensitivity; Humans; Immunoglobulin E; Immunoglobulin G; Kenya; Male; Prevalence; Red Meat; Trichuris; Virginia; Young Adult
PubMed: 33539899
DOI: 10.1016/j.jaci.2020.12.650 -
Revista Brasileira de Parasitologia... 2023The aim of the present study was to assess morphologic and genetic data on ascariasis in swine (Sus scrofa domesticus) and humans in low-resource rural and periurban...
The aim of the present study was to assess morphologic and genetic data on ascariasis in swine (Sus scrofa domesticus) and humans in low-resource rural and periurban communities in the state of Piauí, Brazil. Our cross-sectional survey included 100 fecal samples obtained from swine and 682 samples from humans. Fifteen pigs were necropsied. Human and porcine fecal samples were examined to identify Ascaris eggs. Parasites obtained in the swine necropsies were studied using scanning electron microscopy (SEM), and the mitochondrial gene encoding the cytochrome oxidase 1 (cox1) enzyme was partially amplified and sequenced for molecular taxonomy and phylogenetic analyses. The overall prevalence of Ascaris eggs in the swine fecal samples was 16/100 (16%). No Ascaris eggs were identified in the human fecal samples. SEM of six worms recovered from pigs demonstrated morphological characteristics of A. suum. Cox1 sequences were compatible with A. suum reference sequences. Original and reference (GenBank) nucleotide sequences were organized into clusters that did not segregate the parasites by host species or and region. The largest haplogroups were dominated by haplotypes H01, H02 and H31. In the communities studied, there was no epidemiological evidence of the zoonotic transmission of ascariasis at the human-swine interface.
Topics: Humans; Animals; Swine; Ascaris suum; Ascariasis; Phylogeny; Brazil; Cross-Sectional Studies; Ascaris; Swine Diseases
PubMed: 37851714
DOI: 10.1590/S1984-29612023057 -
The Korean Journal of Parasitology Apr 2018The giant roundworm infects pigs and people worldwide and causes serious diseases. The taxonomic relationship between and is still unclear. The purpose of the present...
The giant roundworm infects pigs and people worldwide and causes serious diseases. The taxonomic relationship between and is still unclear. The purpose of the present study was to investigate the genetic diversity and population genetic structure of 258 specimens from humans and pigs from 6 sympatric regions in -endemic regions of China using existing simple sequence repeat data. The microsatellite markers showed a high level of allelic richness and genetic diversity in the samples. Each of the populations demonstrated excess homozygosity (Ho
0). According to a genetic differentiation index (Fst=0.0593), there was a high-level of gene flow in the populations. A hierarchical analysis on molecular variance revealed remarkably high levels of variation within the populations. Moreover, a population structure analysis indicated that populations fell into 3 main genetic clusters, interpreted as , , and a hybrid of the species. We speculated that humans can be infected with , , and the hybrid, but pigs were mainly infected with . This study provided new information on the genetic diversity and population structure of from human and pigs in China, which can be used for designing control strategies. It can also be beneficial to understand the introgression of host affiliation. Topics: Alleles; Animals; Ascariasis; Ascaris; China; Genetic Variation; Homozygote; Humans; Microsatellite Repeats; Swine; Swine Diseases
PubMed: 29742872
DOI: 10.3347/kjp.2018.56.2.175 -
PloS One 2022Specific collagens and insoluble proteins called cuticlins are major constituents of the nematode cuticles. The epicuticle, which forms the outermost electron-dense...
Specific collagens and insoluble proteins called cuticlins are major constituents of the nematode cuticles. The epicuticle, which forms the outermost electron-dense layer of the cuticle, is composed of another category of insoluble proteins called epicuticlins. It is distinct from the insoluble cuticlins localized in the cortical layer and the fibrous ribbon underneath lateral alae. Our objective was to identify and characterize genes and their encoded proteins forming the epicuticle. The combination between previously obtained laboratory results and recently made available data through the whole-genome shotgun contigs (WGS) and the transcriptome Shotgun Assembly (TSA) sequencing projects of Ascaris suum allowed us to identify the first epicuticlin gene, Asu-epic-1, on the chromosome VI. This gene is formed of exon1 (55 bp) and exon2 (1067 bp), separated by an intron of 1593 bp. Exon 2 is formed of tandem repeats (TR) whose number varies in different cDNA and genomic clones of Asu-epic-1. These variations could be due to slippage of the polymerases during DNA replication and RNA transcription leading to insertions and deletions (Indels). The deduced protein, Asu-EPIC-1, consists of a signal peptide of 20 amino acids followed by 353 amino acids composed of seven TR of 49 or 51 amino acids each. Three highly conserved tyrosine motifs characterize each repeat. The GYR motif is the Pfam motif PF02756 present in several cuticular proteins of arthropods. Asu-EPIC-1 is an intrinsically disordered protein (IDP) containing seven predicted molecular recognition features (MoRFs). This type of protein undergoes a disorder-to-order transition upon binding protein partners. Three epicuticular sequences have been identified in A. suum, Ascaris lumbricoides, and Toxocara canis. Homologous epicuticular proteins were identified in over 50 other nematode species. The potential of this new category of proteins in forming the nematode cuticle through covalent interactions with other cuticular components, particularly with collagens, is discussed. Their localization in the outermost layer of the nematode body and their unique structure render them crucial candidates for biochemical and molecular interaction studies and targets for new biotechnological and biomedical applications.
Topics: Animals; Arthropods; Nematoda; Ascaris suum; Collagen; Amino Acids
PubMed: 36301857
DOI: 10.1371/journal.pone.0274751 -
PLoS Neglected Tropical Diseases 2013The taxonomic distinctiveness of Ascaris lumbricoides and A. suum, two of the world's most significant nematodes, still represents a much-debated scientific issue....
BACKGROUND
The taxonomic distinctiveness of Ascaris lumbricoides and A. suum, two of the world's most significant nematodes, still represents a much-debated scientific issue. Previous studies have described two different scenarios in transmission patterns, explained by two hypotheses: (1) separated host-specific transmission cycles in highly endemic regions, (2) a single pool of infection shared by humans and pigs in non-endemic regions. Recently, A. suum has been suggested as an important cause of human ascariasis in endemic areas such as China, where cross-infections and hybridization have also been reported. The main aims of the present study were to investigate the molecular epidemiology of human and pig Ascaris from non-endemic regions and, with reference to existing data, to infer the phylogenetic and phylogeographic relationships among the samples.
METHODOLOGY
151 Ascaris worms from pigs and humans were characterized using PCR-RFLP on nuclear ITS rDNA. Representative geographical sub-samples were also analysed by sequencing a portion of the mitochondrial cox1 gene, to infer the extent of variability at population level. Sequence data were compared to GenBank sequences from endemic and non-endemic regions.
PRINCIPAL FINDINGS
No fixed differences between human and pig Ascaris were evident, with the exception of the Slovak population, which displays significant genetic differentiation. The RFLP analysis confirmed pig as a source of human infection in non-endemic regions and as a corridor for the promulgation of hybrid genotypes. Epidemiology and host-affiliation seem not to be relevant in shaping molecular variance. Phylogenetic and phylogeographical analyses described a complex scenario, involving multiple hosts, sporadic contact between forms and an ancestral taxon referable to A. suum.
CONCLUSIONS/SIGNIFICANCE
These results suggest the existence of homogenizing gene flow between the two taxa, which appear to be variants of a single polytypic species. This conclusion has implications on the systematics, transmission and control programs relating to ascariasis.
Topics: Animals; Ascaris; DNA, Mitochondrial; DNA, Ribosomal; Gene Flow; Humans; Phylogeography; Polymorphism, Restriction Fragment Length; Swine
PubMed: 23593529
DOI: 10.1371/journal.pntd.0002170 -
Parasites & Vectors Dec 2023The synanthropic house fly (Musca domestica) can potentially contribute to the mechanical spread of eggs of Taenia and Ascaris spp. in the environment and between hosts....
BACKGROUND
The synanthropic house fly (Musca domestica) can potentially contribute to the mechanical spread of eggs of Taenia and Ascaris spp. in the environment and between hosts. However, the absence of validated protocols to recover eggs hampers an in-depth analysis of the house fly's role in parasite egg transmission.
METHODS
The gastrointestinal tract and exoskeleton of euthanized house flies were spiked with Taenia saginata eggs. The performance of several recovery protocols, in terms of both the recovery rate and ease-of-use, was (microscopically) evaluated and compared. These protocols employed steps such as washing, maceration, filtration, flotation and both passive and centrifugal sedimentation. The final validated protocols were subsequently evaluated for the recovery of Ascaris suum eggs.
RESULTS
The final protocol validated for the recovery of T. saginata eggs from the house fly's gastrointestinal tract involved homogenization in phosphate-buffered saline and centrifugation at 2000 g for 2 min, yielding a recovery rate of 79.7%. This protocol required 6.5 min to perform (which included 1.5 min of hands-on time) and removed large debris particles that could hinder the differentiation of eggs from debris. Similarly, the final protocol validated for the recovery of T. saginata eggs from the fly's exoskeleton involved washing by vortexing for 2 min in Tween 80 (0.05%), 15 min of passive sedimentation and centrifugation at 2000 g for 2 min, yielding a recovery rate of 77.4%. This protocol required 20.5 min to perform (which included 3.5 min of hands-on time) and successfully removed debris. The same protocols yielded recovery rates of 74.2% and 91.5% for the recovery of A. suum eggs from the fly's gastrointestinal tract and exoskeleton, respectively.
CONCLUSIONS
Effective, simple and easy-to-use protocols were developed and validated for the recovery of T. saginata and A. suum eggs from the house fly's gastrointestinal tract and exoskeleton. These protocols can be applied to investigate the importance of flies as parasite egg transmitters in laboratory and field settings.
Topics: Animals; Taenia saginata; Ascaris suum; Exoskeleton Device; Ovum; Houseflies; Gastrointestinal Tract; Parasite Egg Count
PubMed: 38110985
DOI: 10.1186/s13071-023-06077-5 -
PLoS Neglected Tropical Diseases Feb 2019
Topics: Animals; Ascaris; Ovum; Sewage; Wastewater; Water Purification
PubMed: 30789908
DOI: 10.1371/journal.pntd.0007020 -
International Journal of Environmental... Jan 2022Wastewater sludge represents an important resource for reuse in agriculture. However, potentially harmful pathogens are a main threat in this context. Thus, the aim of...
Wastewater sludge represents an important resource for reuse in agriculture. However, potentially harmful pathogens are a main threat in this context. Thus, the aim of this study was to examine the presence of helminth ova and protozoan cysts in dried sewage sludge samples collected from ten wastewater treatment plants (WWTPs) located in eight governorates in Tunisia. Based on morphological criteria, protozoan cysts of spp., //, and , were detected in all dried sludge composite samples (N = 116) from the investigated WWTPs. The mean concentration ranged from 1.4 to 10.7 cysts per 100 g dry matter (DM). The identified helminth eggs were spp., , Taeniid eggs, , , and hookworm species. spp. and Taeniid eggs were detected in 56.9 and 74.1% of analyzed samples, respectively. The presence of spp., , and spp. eggs in dried sewage sludge samples was low (0.9, 1.7, and 2.6%, respectively). The mean concentration of helminth eggs during the three-year study was less than 1 egg/100 g DM. All examined dried sewage sludge sample contents were below the WHO (2006) and US EPA (2003) recommendations, and thus, the sludge can potentially be reused in agriculture.
Topics: Agriculture; Animals; Ascaris; Sewage; Toxocara; Tunisia
PubMed: 35162680
DOI: 10.3390/ijerph19031657 -
Protein Science : a Publication of the... Oct 1994Ascaris hemoglobin consists of 8 subunits, each of which contains a C-terminal peptide with the sequence Glu-Glu-Lys-His repeated 4 times. When plotted on a beta-strand,... (Review)
Review
Ascaris hemoglobin consists of 8 subunits, each of which contains a C-terminal peptide with the sequence Glu-Glu-Lys-His repeated 4 times. When plotted on a beta-strand, this sequence leads to alternate lysines and glutamates on one side of the strand, and alternate glutamates and histidines on the other side, suggestive of a polar zipper that links the subunits together. A computer search of the protein database showed that the same or similar sequences also occur in other proteins. Some contain long repeats of Asp-Arg or Glu-Arg, among them the small nuclear ribonucleo-U1 70K protein, which is an autoantigen in systemic lupus erythematosis. These repeats appear to constitute the dominant epitopes in the autoimmune reaction. Single chains with Asp-Arg repeats may form alpha-helices in which alternate positively charged ridges and negatively charged grooves compensate each other. Several separate chains with Asp-Arg repeats could compensate each other's charges optimally by zipping together to beta-sheets. Several homeodomains of Drosophila, as well as the human transcription factor SP1, contain repeats of glutamines. Molecular modeling, circular dichroism, and electron and X-ray diffraction studies of a synthetic poly(L-glutamine) showed that it forms beta-sheets held together by hydrogen bonds between the main-chain and side-chain amides. Published data suggest that the function of these glutamine repeats consists of joining essential transcription factors bound to distant segments of DNA.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Amino Acid Sequence; Animals; Ascaris; Genetic Diseases, Inborn; Glutamine; Hemoglobins; Humans; Lupus Erythematosus, Systemic; Molecular Sequence Data; Nervous System Diseases; Repetitive Sequences, Nucleic Acid; Ribonucleoproteins, Small Nuclear
PubMed: 7849580
DOI: 10.1002/pro.5560031002