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International Journal of Molecular... Jul 2023This review of human amoebiasis is based on the most current knowledge of pathogenesis, diagnosis, treatment, and Entamoeba/microbiota interactions. The most relevant... (Review)
Review
This review of human amoebiasis is based on the most current knowledge of pathogenesis, diagnosis, treatment, and Entamoeba/microbiota interactions. The most relevant findings during this last decade about the parasite and the disease are related to the possibility of culturing trophozoites of different isolates from infected individuals that allowed the characterization of the multiple pathogenic mechanisms of the parasite and the understanding of the host-parasite relationship in the human. Second, the considerable advances in molecular biology and genetics help us to analyze the genome of , their genetic diversity, and the association of specific genotypes with the different amoebic forms of human amoebiasis. Based on this knowledge, culture and/or molecular diagnostic strategies are now available to determine the species and genotype responsible for invasive intestinal or extraintestinal amoebiasis cases. Likewise, the extensive knowledge of the immune response in amoebiasis with the appearance of new technologies made it possible to design diagnostic tools now available worldwide. Finally, the understanding of the interaction between the species and the intestinal microbiota aids the understanding of the ecology of this parasite in the human environment. These relevant findings will be discussed in this review.
Topics: Humans; Entamoeba histolytica; Ecosystem; Amebiasis; Dysentery, Amebic; Intestines; Entamoeba
PubMed: 37511519
DOI: 10.3390/ijms241411755 -
PLoS Pathogens May 2020Calcium signaling plays a key role in many essential processes in almost all eukaryotic systems. It is believed that it may also be an important signaling system of the... (Review)
Review
Calcium signaling plays a key role in many essential processes in almost all eukaryotic systems. It is believed that it may also be an important signaling system of the protist parasite Entamoeba histolytica. Motility, adhesion, cytolysis, and phagocytosis/trogocytosis are important steps in invasion and pathogenesis of E. histolytica, and Ca2+ signaling is thought to be associated with these processes leading to tissue invasion. There are a large number of Ca2+-binding proteins (CaBPs) in E. histolytica, and a number of these proteins appear to be associated with different steps in pathogenesis. The genome encodes 27 EF-hand-containing CaBPs in addition to a number of other Ca2+-binding domain/motif-containing proteins, which suggest intricate calcium signaling network in this parasite. Unlike other eukaryotes, a typical calmodulin-like protein has not been seen in E. histolytica. Though none of the CaBPs display sequence similarity with a typical calmodulin, extensive structural similarity has been seen in spite of lack of significant functional overlap with that of typical calmodulins. One of the unique features observed in E. histolytica is the identification of CaBPs (EhCaBP1, EhCaBP3) that have the ability to directly bind actin and modulate actin dynamics. Direct interaction of CaBPs with actin has not been seen in any other system. Pseudopod formation and phagocytosis are some of the processes that require actin dynamics, and some of the amoebic CaBPs (EhC2Pk, EhCaBP1, EhCaBP3, EhCaBP5) participate in this process. None of these E. histolytica CaBPs have any homolog in organisms other than different species of Entamoeba, suggesting a novel Ca2+ signaling pathway that has evolved in this genus.
Topics: Actins; Calcium; Calcium-Binding Proteins; Calmodulin; Entamoeba histolytica; Entamoebiasis; Phagocytosis; Protozoan Proteins
PubMed: 32379809
DOI: 10.1371/journal.ppat.1008214 -
Current Opinion in Microbiology Dec 2020Entamoeba histolytica, an anaerobic protozoan, is an important global health problem. This parasite has a biphasic life cycle consisting of a dormant cyst stage which is... (Review)
Review
Entamoeba histolytica, an anaerobic protozoan, is an important global health problem. This parasite has a biphasic life cycle consisting of a dormant cyst stage which is environmentally resistant and transmits the infection, and the proliferative trophozoite stage which is motile and causes invasive disease. The stage conversion process remains poorly understood despite being central to amoebic biology. In this review, we will highlight recent progress in our understanding of Entamoeba stage conversion including dissecting transcriptome analysis in development, characterization of transcriptional networks, demonstration of epigenetic regulation, and role of small molecules that regulate Entamoeba development.
Topics: Animals; Entamoeba histolytica; Entamoebiasis; Epigenesis, Genetic; Gene Regulatory Networks; Humans; Life Cycle Stages; Protozoan Proteins
PubMed: 33032142
DOI: 10.1016/j.mib.2020.09.005 -
Boletin Medico Del Hospital Infantil de... 2022Amoebiasis is an intestinal parasitosis caused by the protozoan Entamoeba histolytica that represents the third leading cause of mortality due to parasitosis. It is a...
Amoebiasis is an intestinal parasitosis caused by the protozoan Entamoeba histolytica that represents the third leading cause of mortality due to parasitosis. It is a prevalent disease in tropical climate regions with poor or absent sanitary services. Microscopy and antigen detection techniques are routinely used to diagnose amoebiasis because of their low cost and ease of application. However, these techniques do not differentiate E. histolytica infections and other potentially pathogenic species such as Entamoeba moshkovskii or Entamoeba bangladeshi. Therefore, in the last decades, molecular tests that allow correct identification of the causal agent of amoebiasis and the establishment of the prevalence of the infecting species have been developed. Techniques based on nucleic acids, such as conventional, multiplex, or real-time polymerase chain reaction (PCR), are being seriously considered in clinical laboratories, because they detect the etiologic agent directly from the sample without the need for previous prolonged culture, thus reducing diagnostic time. Also, the nested PCR test and the sequencing of ribosomal markers have allowed the identification of new parasitic species in humans, such as E. moshkovskii and E. bangladeshi, and an improved characterization of the known infecting species. The application of multiplex platforms allows the simultaneous identification of infecting species, increasing the sensitivity and specificity of these techniques. Therefore, the molecular diagnosis of amoebiasis is projected as an innovative tool in the fight against this parasitosis.
Topics: Amebiasis; Entamoeba; Entamoeba histolytica; Entamoebiasis; Feces; Humans
PubMed: 35086128
DOI: 10.24875/BMHIM.21000044 -
Parasite Immunology 2012Invasive amoebiasis caused by Entamoeba histolytica is a major global health problem. Virulence is a rare outcome of infection, occurring in fewer than 1 in 10... (Review)
Review
Invasive amoebiasis caused by Entamoeba histolytica is a major global health problem. Virulence is a rare outcome of infection, occurring in fewer than 1 in 10 infections. Not all strains of the parasite are equally virulent, and understanding the mechanisms and causes of virulence is an important goal of Entamoeba research. The sequencing of the genome of E. histolytica and the related avirulent species Entamoeba dispar has allowed whole-genome-scale analyses of genetic divergence and differential gene expression to be undertaken. These studies have helped elucidate mechanisms of virulence and identified genes differentially expressed in virulent and avirulent parasites. Here, we review the current status of the E. histolytica and E. dispar genomes and the findings of a number of genome-scale studies comparing parasites of different virulence.
Topics: Animals; Entamoeba; Entamoeba histolytica; Entamoebiasis; Genome, Protozoan; Host-Parasite Interactions; Humans; Protozoan Proteins; Species Specificity; Virulence
PubMed: 21810102
DOI: 10.1111/j.1365-3024.2011.01325.x -
Polish Journal of Microbiology 2020The present study was conducted to evaluate the infection rates of , and among asymptomatic individuals in Erbil City, northern Iraq. The research intent was to...
The present study was conducted to evaluate the infection rates of , and among asymptomatic individuals in Erbil City, northern Iraq. The research intent was to discover whether pathogenic or nonpathogenic species cause a high rate of symptomless infections. Stool samples were microscopically examined, and the 18S-rRNA gene was targeted utilizing the nested PCR technique in the positive specimens. Initial results based on morphological features showed that the prevalence rate was 7.4%. Significantly higher rates of infections were seen in females than in males and in low-income people than in moderate-income people. The incidence rates among the asymptomatic individuals, as determined by molecular analysis, were as follows: - 6%, - 4.3%, and - 0.3%. Of all the positive samples, a single infection with was identified in 41.4% samples; the single infection with in 18.6% samples, 35.7% samples had mixed infections with two species, and 4.3% had mixed infections with three species. The current study concluded that 7.4% of healthy people, who live in the endemic area under investigation, carry species asymptomatically. Additionally, the majority of asymptomatic infections were caused by the pathogenic (81.4%) compared to (58.6%), and with the lowest rate of infection. Single and co-infections with and were noted. , which was identified for the first time in the region, was only seen in mixed infections. The present study was conducted to evaluate the infection rates of , and among asymptomatic individuals in Erbil City, northern Iraq. The research intent was to discover whether pathogenic or nonpathogenic species cause a high rate of symptomless infections. Stool samples were microscopically examined, and the 18S-rRNA gene was targeted utilizing the nested PCR technique in the positive specimens. Initial results based on morphological features showed that the prevalence rate was 7.4%. Significantly higher rates of infections were seen in females than in males and in low-income people than in moderate-income people. The incidence rates among the asymptomatic individuals, as determined by molecular analysis, were as follows: – 6%, – 4.3%, and – 0.3%. Of all the positive samples, a single infection with was identified in 41.4% samples; the single infection with in 18.6% samples, 35.7% samples had mixed infections with two species, and 4.3% had mixed infections with three species. The current study concluded that 7.4% of healthy people, who live in the endemic area under investigation, carry species asymptomatically. Additionally, the majority of asymptomatic infections were caused by the pathogenic (81.4%) compared to (58.6%), and with the lowest rate of infection. Single and co-infections with and were noted. , which was identified for the first time in the region, was only seen in mixed infections.
Topics: DNA, Protozoan; Entamoeba; Entamoebiasis; Feces; Female; Humans; Iraq; Male; Polymerase Chain Reaction; Prevalence; RNA, Ribosomal, 18S; Species Specificity
PubMed: 32755082
DOI: 10.33073/pjm-2020-028 -
Acta Parasitologica Mar 2021Yak, a predominant livestock of plateau areas, is known as a host to many parasites. And the genus Entamoeba, the third-common cause of the mortality worldwide from...
BACKGROUND
Yak, a predominant livestock of plateau areas, is known as a host to many parasites. And the genus Entamoeba, the third-common cause of the mortality worldwide from parasitic diseases, was discovered in yaks once.
METHODS
We investigated the distribution and species of Entamoeba spp. from yaks in Qinghai province, northwestern China, by collecting 1027 yak fecal samples. All samples were divided according to seven geographical sites, four seasons, and two age groups of yaks. After extracting DNA, polymerase chain reaction (PCR) was performed to amplify the 18S rRNA gene, and sequences were analyzed with phylogenetic method.
RESULTS
We observed an overall Entamoeba positive rate of 36.32% (373/1027) in yaks from Qinghai province. The common species included Entamoeba bovis (284/373), Entamoeba sp. MG107/BEL (79/373), Entamoeba sp. ribosomal lineage (RL) two (8/373), and Entamoeba sp. RL9 (2/373). According to the result of statistical analysis, Entamoeba infection rate was the highest in summer and significantly differed from that observed during other seasons (P < 0.05). The yaks from Golog had the highest prevalence of Entamoeba among all geographical origins in Qinghai province (P < 0.05). However, no significant difference was observed (P > 0.05) among different age groups, as evident from a positive rate of 39.58% in ≤ 6-month and 36.16% in > 6-month yaks.
CONCLUSION
These results indicate the prevalence and predominant species of Entamoeba in yaks. To our knowledge, this is the first study to report E. bovis, Entamoeba sp. RL2, and Entamoeba sp. RL9 in Chinese yaks.
Topics: Animals; Cattle; Cattle Diseases; China; Entamoeba; Feces; Phylogeny; RNA, Ribosomal, 18S
PubMed: 32779095
DOI: 10.1007/s11686-020-00258-3 -
Frontiers in Immunology 2022Gasdermins (GSDMs) are a group of proteins that are cleaved by inflammatory caspases to induce pore formation in the plasma membrane to cause membrane permeabilization... (Review)
Review
Gasdermins (GSDMs) are a group of proteins that are cleaved by inflammatory caspases to induce pore formation in the plasma membrane to cause membrane permeabilization and lytic cell death or pyroptosis. All GSDMs share a conserved structure, containing a cytotoxic N-terminal (NT) pore-forming domain and a C-terminal (CT) repressor domain. () in contact with macrophages, triggers outside-in signaling to activate inflammatory caspase-4/1 the noncanonical and canonical pathway to promote cleavage of gasdermin D (GSDMD). Cleavage of GSDMD removes the auto-inhibition that masks the active pore-forming NT domain in the full-length protein by interactions with GSDM-CT. The cleaved NT-GSDMD monomers then oligomerize to form pores in the plasma membrane to facilitate the release of IL-1β and IL-18 with a measured amount of pyroptosis. Pyroptosis is an effective way to counteract intracellular parasites, which exploit replicative niche to avoid killing. To date, most GSDMs have been verified to perform pore-forming activity and GSDMD-induced pyroptosis is rapidly emerging as a mechanism of anti-microbial host defence. Here, we review our comprehensive and current knowledge on the expression, activation, biological functions, and regulation of GSDMD cleavage with emphases on physiological scenario and related dysfunctions of each GSDM member as executioner of cell death, cytokine secretion and inflammation against and other protozoan parasitic infections.
Topics: Animals; Caspase 1; Cell Membrane; Entamoeba histolytica; Parasites; Pyroptosis
PubMed: 35795683
DOI: 10.3389/fimmu.2022.900553 -
CMAJ : Canadian Medical Association... Sep 2013
Review
Topics: Antiprotozoal Agents; Entamoeba; Entamoeba histolytica; Entamoebiasis; Humans
PubMed: 23589427
DOI: 10.1503/cmaj.121576 -
Parasites & Vectors Mar 2021Entamoeba species harbored by humans have different degrees of pathogenicity. The present study explores the intra- and interspecific diversity, phylogenetic...
BACKGROUND
Entamoeba species harbored by humans have different degrees of pathogenicity. The present study explores the intra- and interspecific diversity, phylogenetic relationships, prevalence and distribution of tetra- and octonucleated cyst-producing Entamoeba in different Brazilian regions.
METHODS
Cross-sectional studies were performed to collect fecal samples (n = 1728) and sociodemographic data in communities located in four Brazilian biomes: Atlantic Forest, Caatinga, Cerrado, and Amazon. Fecal samples were subjected to molecular analysis by partial small subunit ribosomal DNA sequencing (SSU rDNA) and phylogenetic analysis.
RESULTS
Light microscopy analysis revealed that tetranucleated cysts were found in all the studied biomes. The highest positivity rates were observed in the age group 6-10 years (23.21%). For octonucleated cysts, positivity rates ranged from 1 to 55.1%. Sixty SSU rDNA Entamoeba sequences were obtained, and four different species were identified: the octonucleated E. coli, and the tetranucleated E. histolytica, E. dispar, and E. hartmanni. Novel haplotypes (n = 32) were characterized; however, new ribosomal lineages were not identified. The Entamoeba coli ST1 subtype predominated in Atlantic Forest and Caatinga, and the ST2 subtype was predominant in the Amazon biome. E. histolytica was detected only in the Amazon biome. In phylogenetic trees, sequences were grouped in two groups, the first containing uni- and tetranucleated and the second containing uni- and octonucleated cyst-producing Entamoeba species. Molecular diversity indexes revealed a high interspecific diversity for tetra- and octonucleated Entamoeba spp. (H ± SD = 0.9625 ± 0.0126). The intraspecific diversity varied according to species or subtype: E. dispar and E. histolytica showed lower diversity than E. coli subtypes ST1 and ST2 and E. hartmanni.
CONCLUSIONS
Tetra- and octonucleated cyst-producing Entamoeba are endemic in the studied communities; E. histolytica was found in a low proportion and only in the Amazon biome. With regard to E. coli, subtype ST2 was predominant in the Amazon biome. The molecular epidemiology of Entamoeba spp. is a field to be further explored and provides information with important implications for public health.
Topics: Adolescent; Brazil; Child; Child, Preschool; Cross-Sectional Studies; DNA, Protozoan; Ecosystem; Entamoeba; Entamoebiasis; Feces; Female; Genetic Variation; Humans; Infant; Infant, Newborn; Male; Phylogeny; Prevalence; Sequence Analysis, DNA
PubMed: 33731176
DOI: 10.1186/s13071-021-04672-y