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Scientific Reports Feb 2022A hallmark of ribosomal RNA (rRNA) are 2'-O-methyl groups that are introduced sequence specifically by box C/D small nucleolar RNAs (snoRNAs) in ribonucleoprotein...
A hallmark of ribosomal RNA (rRNA) are 2'-O-methyl groups that are introduced sequence specifically by box C/D small nucleolar RNAs (snoRNAs) in ribonucleoprotein particles. Most data on this chemical modification and its impact on RNA folding and stability are derived from organisms of the Opisthokonta supergroup. Using bioinformatics and RNA-seq data, we identify 30 novel box C/D snoRNAs in Dictyostelium discoideum, many of which are differentially expressed during the multicellular development of the amoeba. By applying RiboMeth-seq, we find 49 positions in the 17S and 26S rRNA 2'-O-methylated. Several of these nucleotides are substoichiometrically modified, with one displaying dynamic modification levels during development. Using homology-based models for the D. discoideum rRNA secondary structures, we localize many modified nucleotides in the vicinity of the ribosomal A, P and E sites. For most modified positions, a guiding box C/D snoRNA could be identified, allowing to determine idiosyncratic features of the snoRNA/rRNA interactions in the amoeba. Our data from D. discoideum represents the first evidence for ribosome heterogeneity in the Amoebozoa supergroup, allowing to suggest that it is a common feature of all eukaryotes.
Topics: Computational Biology; Dictyostelium; Methylation; Nucleic Acid Conformation; RNA Processing, Post-Transcriptional; RNA Stability; RNA, Ribosomal; RNA, Small Nucleolar; RNA-Seq; Ribosomes; Structure-Activity Relationship
PubMed: 35121764
DOI: 10.1038/s41598-022-05447-w -
Journal of Veterinary Diagnostic... May 2023Free-living amoebae are rare causes of morbidity and mortality in humans and animals around the globe. Because the route of exposure and clinical progression of disease... (Review)
Review
Free-living amoebae are rare causes of morbidity and mortality in humans and animals around the globe. Because the route of exposure and clinical progression of disease caused by different species of amoebae may vary in people and animals, determining the species of amoeba present is important. We describe here a fatal infection by the free-living amoeba in a Siberian tiger (). The 17-y-old patient had a rapid clinical decline after a peracute onset of severe lethargy, dull mentation, and anorexia. Autopsy did not identify a cause of death. Histology revealed inflammation associated with amoebic trophozoites in the brain, lungs, and iris of one eye. These amoebae were confirmed to be based on a PCR assay and sequencing. Although there are subtle morphologic differences between cyst stages of spp., , and when present and identified on routine staining, other modalities, including PCR, immunofluorescence, electron microscopy, and immunohistochemistry, are typically utilized to confirm the pathogen involved in these cases. We review the reports of balamuthosis in animals.
Topics: Humans; Animals; Tigers; Amebiasis; Amoeba; Acanthamoeba; Naegleria fowleri; Balamuthia mandrillaris
PubMed: 36908206
DOI: 10.1177/10406387231160771 -
Parasite Immunology Aug 2020Gill health is one of the main health challenges for Atlantic salmon (Salmo salar L.) mariculture worldwide, and amoebic gill disease (AGD), caused by the marine... (Review)
Review
Gill health is one of the main health challenges for Atlantic salmon (Salmo salar L.) mariculture worldwide, and amoebic gill disease (AGD), caused by the marine ectoprotozoan Neoparamoeba perurans, is currently one of the most significant diseases in terms of prevalence and economic impact. This review describes the host response of Atlantic salmon to the disease, focusing on the pathological changes, immune response and mechanisms underlying the prominent epithelial proliferation and mucus hypersecretion occurring in affected fish. Health management strategies and risk factors are also discussed.
Topics: Amebiasis; Amoebozoa; Animals; Fish Diseases; Gills; Mucus; Salmo salar
PubMed: 32564378
DOI: 10.1111/pim.12766 -
European Journal of Protistology Apr 2017Testate amoebae are eukaryotic microorganisms characterized by the presence of an external shell (test). The shell morphology is used as a diagnostic character, but...
Testate amoebae are eukaryotic microorganisms characterized by the presence of an external shell (test). The shell morphology is used as a diagnostic character, but discordance between morphological and molecular data has been demonstrated in groups of arcellinids (Amoebozoa), one of the principal groups of testate amoebae. Morphology of the test is supposed to differentiate genera and species and it is applied in ecological, monitoring and paleontological studies. However, if phenotype does not reflect genotype, conclusions in these types of studies become severely impaired. The objective of this work is to evaluate the morphometrical and morphological variation of the closely related and morphologically similar taxa Arcella intermedia laevis Tsyganov and Mazei, 2006 and Arcella intermedia (Deflandre 1928) Tsyganov and Mazei, 2006 in nature and in cultured individuals and see how these are correlated with molecular data. Our results demonstrate that phenotypic plasticity in Arcella intermedia make morphological distinctions impossible in both taxa. Arcella intermedia and Arcella intermedia laevis are molecularly identical for SSU rDNA and a mitochondrial molecular marker (NAD9/7). We conclude that morphological techniques alone cannot identify phenotypic plasticity from natural populations. More work is clearly needed to better understand the morphological, morphometric and molecular variability in these organisms.
Topics: Amoebozoa; DNA, Protozoan; NADH Dehydrogenase; Phenotype; Phylogeny; Species Specificity
PubMed: 28073604
DOI: 10.1016/j.ejop.2016.11.003 -
Journal of Tropical Pediatrics Jan 2021Naegleria fowleriis a thermophilic free-living ameba that is found in warm, fresh water and causes primary amebic meningoencephalitis (PAM) in humans with high mortality...
Naegleria fowleriis a thermophilic free-living ameba that is found in warm, fresh water and causes primary amebic meningoencephalitis (PAM) in humans with high mortality rate. Here we report a case of newborn admitted with destructive clinical features of PAM after having bath with unchlorinated well water on a summer day.
Topics: Amoeba; Brain; Central Nervous System Protozoal Infections; Fresh Water; Humans; Infant, Newborn; Naegleria fowleri
PubMed: 33381798
DOI: 10.1093/tropej/fmaa100 -
PloS One 2021The inland freshwater bodies in the North-Western Province of Sri Lanka have ideal environmental conditions for the Naegleria species. Therefore, the presence and...
BACKGROUND
The inland freshwater bodies in the North-Western Province of Sri Lanka have ideal environmental conditions for the Naegleria species. Therefore, the presence and prevalence of Naegleria species in the water bodies of North-Western Province were determined by molecular characterization and phylogenetic analysis in this study.
METHODS
A total of 104 water bodies were selected from Kurunegala and Puttalam districts in the North-Western Province of Sri Lanka. Mean turbidity, pH, and temperature were recorded in each water body from three selected site. Centrifuged samples were cultured on non-nutrient agar plates with Escherichia coli. Enflagellation test positive isolates were subjected to DNA extraction and polymerase chain reaction using genus and species-specific primers targeting the internal transcribed spacer region (ITS) and Mp2CL5 gene. Phylogenetic analysis was performed using Bayesian and maximum likelihood (ML) methods.
RESULTS
The prevalence of Naegleria species and N. fowleri in the study area were 23.07% and 1.92%. The prevalence of Naegleria species and the physicochemical parameters of the water bodies showed no significant correlation. Bayesian analysis of the ITS region revealed the Naegleria Sri Lankan (SL) isolates 1, 3, and 4 in a single clade separated from the 2 and 5. Furthermore, Bayesian analysis identified isolates 2 and 5 in the same clade with Naegleria sp. samples and N. Philippinensis forming a sister clade. However, in the ML tree, all isolates were in the same clade with Naegleria sp. samples and N. Philippinensis.
CONCLUSIONS
The present study reports the first isolation of pathogenic N. fowleri from Sri Lanka. Based on Bayesian analysis, SL isolates 2 and 5 form a separate clade from 1, 3, and 4. However, in ML analysis, all isolates are grouped in one clade with Naegleria sp. samples and N. philippinensis. Further investigations are required to confirm these findings.
Topics: Fresh Water; Naegleria fowleri; Phylogeny; Sri Lanka
PubMed: 33705485
DOI: 10.1371/journal.pone.0248510 -
Journal of Biosciences Dec 2014Caspases are cysteine proteases that are important regulators of programmed cell death in animals. Two novel relatives to members of the caspase families metacaspases... (Review)
Review
Caspases are cysteine proteases that are important regulators of programmed cell death in animals. Two novel relatives to members of the caspase families metacaspases and paracaspase have been discovered. Metacaspase type-1 was identified in Acanthamoeba castellanii, an opportunistic protozoan parasite that causes severe diseases in humans. Paracaspase was found in the non-pathogenic protozoan Dictyostelium discoideum. Since their discovery in Acanthamoeba and Dictyostelium, metacaspases and paracaspases have remained poorly characterized. At present we do not have sufficient data about the molecular function of these caspase-like proteins or their role, if any, in programmed cell death. How these caspase proteins function at the molecular level is an important area of study that will provide insight into their potential for treatment therapies against Acanthamoeba infection and other similar parasitic protozoan. Additionally, finding the molecular functions of these caspase-like proteins will provide information concerning their role in more complex organisms.The aim of this article was to review recent discoveries about metacaspases and paracaspases as regulators of apoptotic and non-apoptotic processes.
Topics: Acanthamoeba castellanii; Apoptosis; Caspases; Dictyostelium; Protozoan Proteins
PubMed: 25431419
DOI: 10.1007/s12038-014-9486-0 -
Anais Da Academia Brasileira de Ciencias 2023Within each ecosystem, organisms and populations maintain a complex set of relationships. These interactions can determine the distribution area of a species and play an...
Within each ecosystem, organisms and populations maintain a complex set of relationships. These interactions can determine the distribution area of a species and play an essential role in its evolution. Parasites are ubiquitous components of nature and have a high influence on various aspects of the biology and ecology of organisms, affecting the populations of their hosts and, therefore, their communities and ecosystems. Free-living amoebae are unicellular organisms that can be found in water, soil or air. Some species are of great importance in human health. In Hydra, there are several reports of Hydramoeba hydroxena infections. In this work we present a double parasitosis: two concatenated infectious periods in the host polyp of Hydra vulgaris and Hydra vulgaris pedunculata for three freshwater bodies in the province of Buenos Aires, Argentina. Hydramoeba sp. and Acanthoamoeba sp. unchain a series of anatomical lesions that in all cases cause the death of the polyps due to total disintegration. This finding becomes important at a sanitary level due to the appearance of Acanthoamoeba sp. in waters associated with human recreational activities; For the Hydra genus, the importance lies at an ecological and evolutionary level, considering the possible impact on its natural populations.
Topics: Humans; Animals; Amoeba; Ecosystem; Hydra; Acanthamoeba; Argentina
PubMed: 37162082
DOI: 10.1590/0001-3765202320211025 -
Protist Apr 2017We describe four new species of Flabellula, Leptomyxa and Rhizamoeba and publish new SSU rRNA gene and actin gene sequences of leptomyxids. Using these data we provide...
We describe four new species of Flabellula, Leptomyxa and Rhizamoeba and publish new SSU rRNA gene and actin gene sequences of leptomyxids. Using these data we provide the most comprehensive SSU phylogeny of leptomyxids to date. Based on the analyses of morphological data and results of the SSU rRNA gene phylogeny we suggest changes in the systematics of the order Leptomyxida (Amoebozoa: Lobosa: Tubulinea). We propose to merge the genera Flabellula and Paraflabellula (the genus Flabellula remains valid by priority rule). The genus Rhizamoeba is evidently polyphyletic in all phylogenetic trees; we suggest retaining the generic name Rhizamoeba for the group unifying R. saxonica, R.matisi n. sp. and R. polyura, the latter remains the type species of the genus Rhizamoeba. Based on molecular and morphological evidence we move all remaining Rhizamoeba species to the genus Leptomyxa. New family Rhizamoebidae is established here in order to avoid paraphyly of the family Leptomyxidae. With the suggested changes both molecular and morphological systems of the order Leptomyxida are now fully congruent to each other.
Topics: Microscopy, Electron, Transmission; Phylogeny; Sequence Analysis, DNA; Tubulina
PubMed: 28343121
DOI: 10.1016/j.protis.2016.10.006 -
Annals of Parasitology 2020Amoebosis, caused by the protozoan parasite Entamoeba histolytica is a gastrointestinal infection and the second leading cause of death from parasitic disease worldwide.... (Review)
Review
Amoebosis, caused by the protozoan parasite Entamoeba histolytica is a gastrointestinal infection and the second leading cause of death from parasitic disease worldwide. The disease is endemic in many developing countries and kills over one hundred thousand persons annually. Adequate nutrition composed of macro- and micronutrients in their balanced proportions is central to effective gut immune response and the homeostasis of commensal organisms in the gastrointestinal tract. Entamoeba histolytica is a gut pathobiont that can exploit a shift in nutritional status to cause amoebosis, with extra-intestinal complications. Although undernutrition is rarely a public health concern in high income settings, bioavailability of functional nutrients remains suboptimal. On the other hand, nutrient deficiencies constitute a chronic challenge in very low-income regions. This study sought to review the pivotal influence of malnutrition on intact microbiota and functional immunity, as determinants of susceptibility to amoebosis in the Nigerian example of tropical regions. The dynamics of the infection such as possible coinfection with opportunistic pathogens were also, evaluated. Based on the available reports, we posit that amoebosis is a common tropical infection perpetuated by malnutrition following poor living standard including unhygienic environmental exposure.
Topics: Entamoeba; Entamoeba histolytica; Humans; Microbiota; Nigeria
PubMed: 33126295
DOI: 10.17420/ap6603.265