Appearance Of Trophozoites Research Articles

Evaluation of the Antiparasitic, Antihepatotoxicity, and Antioxidant Efficacy of Quercetin and Chitosan, Either Alone or in Combination, against Infection Induced by Giardia lamblia in Male Rats.

Giardia lamblia (G. lamblia) is one of the most common protozoal infections and a key cause of malabsorption, some cases of mental developmental issues in children, and reduced body weight. The known antiparasitic medications, which are the standard drugs used for parasitic treatment, have several side effects and sometimes exhibit low efficacy. Therefore, the current study aimed to evaluate the treatment with quercetin (QC) or chitosan (CH), either alone or in combination, as possible alternative therapeutic agents that may alleviate the side effects of G. lamblia infections and restore the normal architecture of the intestinal muscles. They are investigated as alternatives to other routinely administered drugs that may gradually lose their efficacy due to human resistance to therapeutic agents. This study was carried out on 50 male albino rats that were divided into five groups with 10 rats in each group: the control group (Group I), the infected non-treated group (Group II), the infected group treated with QC (Group III), the infected treated group with CH (Group IV), and the infected group treated with a combination of QC and CH (Group V). The effect was first evaluated by counting the G. lamblia fecal cysts in the stool, examining histopathological sections of the intestine with the appearance of trophozoites in the infected group, and conducting a transmission electron microscopic examination of the tissues of the small intestine. Alterations in the biochemical parameters of liver and kidney function and the antioxidant enzymes in the liver tissues of SOD, CAT, and GSH, and non-enzymatic markers of lipid peroxidation (MDA) were evaluated. The results showed a significant decline in the number of parasites in the stool samples, with a marked elevation in the number of trophozoites in the intestinal sections of the infected non-treated group as compared to the infected treated groups. The last group, which was treated with a combination of QC and CH, showed the best results in terms of a decline in the infection rate of G. lamblia in stool samples, with a marked and clear improvement in the intestinal mucosa, regular muscles with normal enteric ganglions, and reduced rates of intestinal injuries caused by G. lamblia trophozoites. Both QC and CH had non-toxic effects on the biochemical parameters of the liver and kidneys, as well as pronounced antioxidant activities due to the elevation of SOD, CAT, and GSH in conjunction with a decline in the levels of MDA. A combination of QC and CH can be considered a potent antiparasitic, anti-hepatotoxic, and antioxidant therapeutic agent; it could constitute a promising alternative treatment agent against G. lamblia infection.

Semisynthesis, cytotoxicity, antimalarial evaluation and structure-activity relationship of two series of triterpene derivatives

In this report, we describe the semisynthesis of two series of ursolic and betulinic acid derivatives through designed by modifications at the C-3 and C-28 positions and demonstrate their antimalarial activity against chloroquine-resistant P. falciparum (W2 strain). Structural modifications at C-3 were more advantageous to antimalarial activity than simultaneous modifications at C-3 and C-28 positions. The ester derivative, 3β-butanoyl betulinic acid (7b), was the most active compound (IC50 = 3.4 µM) and it did not exhibit cytotoxicity against VERO nor HepG2 cells (CC50 > 400 µM), showing selectivity towards parasites (selectivity index > 117.47). In combination with artemisinin, compound 7b showed an additive effect (CI = 1.14). While docking analysis showed a possible interaction of 7b with the Plasmodium protease PfSUB1, with an optimum binding affinity of −7.02 kcal/mol, the rather low inhibition displayed on a Bacillus licheniformis subtilisin A protease activity assay (IC50 = 93 µM) and the observed accumulation of ring forms together with a delay of appearance of trophozoites in vitro suggests that the main target of 3β-butanoyl betulinic acid on Plasmodium may be related to other molecules and processes pertaining to the ring stage. Therefore, compound 7b is the most promising compound for further studies on antimalarial chemotherapy. The results obtained in this study provide suitable information about scaffolds to develop novel antimalarials from natural sources.

Development of Eimeria tenella in MDBK cell culture with a note on enhancing effect of preincubation with chicken spleen cells

Eimeria tenella, an intracellular protozoan parasite infecting the epithelial cells of the ceca of chickens, causes severe diarrhea and bleeding that can lead its host to death. It is of interest that E. tenella first penetrate into the mucosal intraepithelial lymphocytes (IEL) before they parasitize crypt or villous epithelial cells. This in vitro study was undertaken to know whether the penetration of E. tenella into such a lymphoid cell is a beneficial step for the parasite survival and development. Three sequential experiments were performed. First, the in vitro established bovine kidney cell line, MDBK cells, were evaluated for use as host cells for E. tenella, through morphological observation. Second, the degree of parasite development and multiplication in MDBK cells was quantitatively assayed using radioisotope-labelled uracil (3H-uracil). Third, the E. tenella sporozoites viability was assayed after preincubation of them with chicken spleen cells. E. tenella oöcysts obtained from the ceca of the infected chickens were used for the source of the sporozoites. Spleen cells (E) obtained from normal chickens (FP strain) were preincubated with the sporozoites (T) at the E:T ratio of 100:1, 50:1 or 25:1 for 4 or 12 hours, and then the mixture was inoculated into the MDBK cell monolayer. Morphologically the infected MDBK cells revealed active schizogonic cycle of E. tenella in 3-4 days, which was characterized by the appearance of trophozoites, and immature and mature schizonts containing merozoites. The 3H-uracil uptake by E. tenella increased gradually in the MDBK cells, which made a plateau after 48-60 hours, and decreased thereafter. The uptake amount of 3H-uracil depended not only upon the inoculum size of the sporozoites but also on the degree of time delay (preincubation; sporozoites only) from excystation to inoculation into MDBK cells. The 3H-uracil uptake became lower as the preincubation time was prolonged. In comparison, after preincubation of sporozoites with spleen cells for 4 or 12 hours, the 3H-uracil uptake was significantly increased compared with that of control group. From the results, it was inferred that, although the penetration of E. tenella sporozoites into the lymphoid cells such as IEL is not an essential step, it should be at least a beneficial one for the survival and development of sporozoites in the chicken intestine.

Intralymphocytic schizonts associated with an initial infection of Saurocytozoon tupinambi in Tupinambis teguixin

An initial natural infection of Saurocytozoon tupinambi in a juvenile Tupinambis teguixin from Venezuela was studied for 131 days following capture of the host. Intralymphocytic parasites appeared in this sequence: small uninucleate and binucleate stages (days 1–31 and again on day 41); schizonts with 3–102 nuclei (days 8–14 and 29–35); immature gametocytes (days 29–35) and apparently mature gametocytes of Saurocytozoon tupinambi from day 41. Maximum parasitemia of trophozoites and binucleate schizonts occurred on day 4 when 11% of lymphocytes were infected. Maximum parasitemia by larger schizonts occurred on day 8 at 0.13% of lymphocytes, while maximum gametocytemia was found on day 49 with 16.4% of lymphocytes parasitized. Two types of schizonts were observed: intralymphocytic and the same type free of host cells, and fragments of varying size which may have been torn from capillary endothelium. Due to presence of concurrent infection by a small Plasmodium species, identity of intralymphocytic asexual stages with S. tupinambi cannot be established. Presence of asexual and sexual stages in the same type of host cells (lymphocytes and close derivatives), sequential appearance of trophozoites, schizonts and gametocytes over a period of 40 days, and correlated fluctuations in lymphocyte density suggest they are conspecific, and that Saurocytozoon, which has a plasmodiid type of sporogony may prove to further differ from leucocytozoids by presence of an asexual cycle in circulating blood cells.

Life cycle of Eimeria stiedae.

KNOWLEDGE of the early development of Eimeria stiedae, before the appearance of trophozoites in the liver of its rabbit host, is remarkably scanty. After initial penetration of the duodenal epithelium by the sporozoites, the earliest observation of trophozoite formation has been 72 h after infection. The route of migration of the sporozoites during this period has long been a subject for speculation, and the most favoured theory has been passage to the liver from the mesenteric lymph node in the portal blood. Slater, Quisenberry and Fitzgerald1 gave support to this theory by reporting the presence of sporozoites in the mucosa after 5–9 h, free and in monocytes in the mesenteric lymph nodes and in monocytes in the peripheral blood 16–20 h after infection.

Intestinal Parasitic Investigation in Temple Rhesus Monkeys of Kathmandu

The rhesus monkeys (Macaca mulatta) of Kathmandu come into frequent contact with humans and due to their habit of residing in the religious and parkland of human proximity, there is possibility of zoonotic and anthroponotic disease transmission between them. So, a prevalence survey of gastrointestinal parasites of these monkeys was conducted during April and May 2005 in three temples Pashupatinath, Swyombhunath and Tripureshwor. Total 121 fresh faecal samples, were collected randomly from these areas that were about fifteen percent of total monkey population. The faecal samples were analyzed by direct smear and concentration methods. The overall parasitization rate was 76.86% with the highest in Pashupatinath (86%) followed by Swyombhunath (74%) and Tripureshwor (61.9%). About 27.96% had single infection while 72.04% had mixed infection. This showed that the presence of one parasite reduced the immunity of the host as a result multiple infections existed. Parasite identifications were based upon the size and appearance of trophozoites, cysts, eggs and larvae of parasites. Both protozoan and helminthes parasites were observed in varying rates in three temples. Three species of protozoa and ten species of helminths were detected by microscopical examination of faecal samples. Human is always prone to be infected by most of these parasites so they are of zoonotic importance. The study will enrich the information on temple monkeys and will support their ecological management in human proximity. DOI: http://dx.doi.org/10.3126/init.v4i0.5530 The Initiation Vol.4 2011 1-7

Observations on the Mechanism of the Parasite Cycle in Falciparum Malaria 1

Summary and ConclusionsA study of the mechanism of the parasite cycle has been made through an analysis of its component trophozoite and gametocyte waves in fifty-five Negro patients, thirty-four of whom were naturally inoculated and twenty-one artificially infected with a single strain of P. falciparum.The day of modal density proves to be a reasonably good centering point for the trophozoite and gametocyte waves to which curves are fitted. Computed densities on the modal day are utilized.Key points in the parasite cycle, the days of first appearance (microscopic detection) of trophozoites and gametocytes following inoculation and the days of maximum or of modal density, are surprisingly constant. Failure of quinine to affect these points and of artificial inoculation to alter greatly the lengths of the segments between them supplies further evidence of the stable nature of the cycle.The timing of certain key points may be altered in individual patients by natural resistance, acquired immunity, or treatment but all points are not similarly affected. The correlations between adjacent segments are predominantly negative indicating that when one is lengthened the other becomes shorter and vice versa so that the cycle is brought back into line.This stability leads to the belief that the events in the parasite cycle are determined prior to the appearance of trophozoites in the peripheral blood and possibly at the time of inoculation.Significant positive correlation exists between the computed densities of trophozoites and gametocytes on the modal day. This relationship supports the thesis that sexual forms arise from the segmenting asexual parasites.The negative relationships between adjacent segments of trophozoite and gametocyte waves indicate, we believe, that production of gametocytes begins prior to the end of the prepatent period and possibly soon after inoculation of the patient. Consequently, the interval of approximately ten days between the first appearance of trophozoites and gametocytes and between their peak densities indicates that a period for development is required by gametocytes over and above that needed for them to accumulate sufficiently to reach microscopic visibility.