Entamoeba histolytica Protozoa

In vitro, allicin has demonstrated activity against gram-positive and gram-negative bacteria as well as fungi (Candida albicans), protozoa (Entamoeba histolytica), and certain viruses. The primary mechanism involves the inhibition of thiol-containing enzymes needed by these microbes. The... 

Among the fungal and protozoal lectins only a few have been studied in detail. One of these is the galactose-specific lectin of the protozoa Entamoeba histolytica. It mediates adhesion of the parasite to human colonic mucin glycoproteins and has a central role in the contact-dependent cytolysis or histolysis for which the parasite is named. A sialic-acid-speeific lectin has been isolated from merozoites of the human malarial parasite, Plasmodium falciparum. An unusual lectin is that of the protozoan Giardia lamblia, specific for mannose-6-phosphate, which is activated by trypsinization. 

MGL catalyzes the o ,7-elimination reaction of methionine to a-ketobutyrate, methanethiol, and ammonia. MGL has been isolated from a number of bacteria, including Pseudomonas putida, Aeromonas sp., Clostridium sporogenes, P. taetrolens, and Brevibacterium linens, from the primitive protozoa Entamoeba histolytica and Trichomonas vaginalis, but is not believed to be present in yeast, plants, or mammals. " " Two MGL isoforms have been isolated from T. vaginali and Entamoeba histolytica, which differ in substrate specificity, overall charge, and catalytic properties. They show a high degree of sequence identity to MGL from Pseudomonas putida. MGL has demonstrated antitumor efficacy in a number of methionine-dependent cancer cell lines. ... 

The Skraup reaction was also used for the synthesis of the amebocide drug iodoquinol. Amebiasis is an infection of the body by the protozoa Entamoeba histolytica with symptoms of acute ameba dysentery, which is accompanied by bloody diarrhea, vomiting, fever, and dehydration. Iodoquinol is considered as a drug of choice for treating asymptomatic or moderate forms of amebiasis. Its preparation relies on the reaction of 2-aminophenol with glycerol in the presence of sulfuric acid. ... 

Bacteria are likely precipitants in many other cases including Escherichia coli, Salmonella species, Shigella species, Vibrio cholerae, and Clostridium difficile. The term dysentery has often been used to describe some of these bacterial infections when associated with serious occurrences of bloody diarrhea. Additionally, acute diarrheal conditions can be prompted by parasites-protozoa such as Entamoeba histolytica, Microsporidium, Giardia lamblia, and Cryptosporidium parvum. Most of these infectious agents can be causes of traveler s diarrhea, a common malady alflicting travelers worldwide. It usually occurs during or just after travel subsequent to the ingestion of fecally-contaminated food or water. It has an abrupt onset but usually subsides within 2 to 3 days. 

Many pathogenic protozoa. Including Trypanosoma brucei (trypanosomiasis or African sleeping sickness), Plasmodium falciparum (malaria), Leishmania species (leishmaniasis), and the intestinal parasites Giardia lamblia and Entamoeba histolytica, depend on farnesylated proteins for growth... 

In addition to the physical and chemical characterization of water and wastewater, it is important that the microbiological constituents be also addressed. The constituent microbiological characterizations to be discussed in this section include the following bacteria, protozoa, and viruses. In addition, qualitative and quantitative tests for the coliform bacteria will also be addressed. The treatment then proceeds to viruses and protozoa. The treatment on protozoa will include discussion on Giardia lamblia, Cryptosporidium parvum, and Entamoeba histolytica. 

FeSODs occurs also in plants (mainly in the chloroplasts) and are common in protozoa, e.g., Tetrahymena pyriformis. Entamoeba histolytica, Plasmodium falciparum, Leishmania chagasi. Trypanosoma cruzi and Trichomonas vaginalis. 

However, some protozoa do give us grief Entamoeba histolytica causes dysentery Trichomonas vaginalis, vagini-... 

Protozoa pathogenic to man which can be transmitted by contaminated water (Entamoeba histolytica, Giardia lamblia, Naegleria gruberi and Acan-thamoeba) are described in Section 4.2.7. 

Another example of deviant biochemistry in protozoa is the utilization, by Entamoeba histolytica, of pyrophosphate in place of the usual ATP, as a coenzyme for phosphofructokinase (Beeves, Serrano and South, 1976). The major path of glucose utilization in this parasite is formation of pyruvate from phospho-gluconate and from 2-keto-3-deoxy-6-phosphogluconate (Florkin and Mason, 1960). 

As indicated already, membrane-associated electron transport has not been demonstrated in mitosomes. Neither cytochromes nor haem proteins have been detected by chemical or spectroscopic analyses in anaerobic protozoa and no components of respiratory complexes I-IV have been identified in the genomes of C. parvum, E. cuniculi, E. histolytica and G. intestinalis (Abrahamsen et al. 2004 Katinka et al. 2001 Loftus et al. 2005 McArthur et al. 2000 Muller 2003). However, low levels of ubiquinone have been detected in Giardia and Entamoeba (Ellis et al. 1994). A limited level of membrane-associated electron transport activity in C. parvum is suggested by the presence... 

Amebiasis ajfects 10% of the world s population. In the U.S., amebiasis is usually seen in those living in crowded, unsanitary conditions. Entamoeba dispar accounts for 90% of human infections and E. histolytica/or only 10%, but only E. histolytica causes human disease. Humans are the only known hosts for these protozoa, which are transmitted almost exclusively by the fecal-oral route. E. histolytica cysts ingested from contaminated food or water transform into trophozoites that reside in the large intestine. Many individuals infected with E. histolytica are asymptomatic but excrete infectious cysts, making them a source for further infections. In others, E. histolytica trophozoites invade the colonic mucosa with resulting colitis and bloody diarrhea (amebic dysentery). Rarely, E. histolytica trophozoites invade through the colonic mucosa and reach the liver via the portal circulation, where they establish an amebic liver abscess. 

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