This study investigated the polymorphism in the P. falciparum chloroquine resistance transporter (pfcrt) gene 11 years after chloroquine (CQ) cessation in Jazan region, southwestern Saudi Arabia. Two hundred and thirty-five P. falciparum isolates were amplified to detect mutations in the pfcrt gene. The pfcrt 76 T molecular marker for CQ resistance was detected in 66.4% (156/235) of the isolates, while the K76 CQ-sensitive wild type was detected in 33.6%. The pfcrt 74I and pfcrt 75E point mutations were each found to be present in 56.2% of isolates, while only four isolates (1.7%) were found to carry the pfcrt 72S mutation. Moreover, four pfcrt haplotypes were identified as follows: the CVIET triple-allele (56.2%), SVMET double-allele (1.7%) and CVMNT single-allele (8.5%) mutant haplotypes and the CVMNK wild haplotype (33.6%). The analysis also revealed significant associations between the prevalence of mutant pfcrt alleles and haplotypes and the age group, governorate and nationality of the patients as well as the parasitaemia level (p
Blastocystis sp. is an enteric protistan parasite that affects individuals worldwide with gastrointestinal symptoms such as abdominal discomfort, diarrhea, and flatulence. However, its pathogenicity is controversial due to its presence among asymptomatic individuals. Blastocystis sp. subtype 3 (ST3) is the most prevalent subtype among humans that have been associated with irritable bowel syndrome (IBS), Crohn's disease, ulcerative colitis, and colorectal cancer. Axenization of the parasite has been shown to impede its growth thus revealing the importance of accompanying bacteria in ensuring Blastocystis sp. survival. This study aims to identify the influence of accompanying bacteria on the growth of Blastocystis sp. ST3. Blastocystis sp. cultures were treated with Meropenem, Vancomycin, and Amoxicillin-Clavulanic acid (Augmentin). Bacteria-containing supernatant of antibiotic-treated and control cultures were isolated and identified through 16 s rRNA sequencing. Morphological changes of antibiotic-treated Blastocystis sp. ST3 were also observed. The cultures treated with meropenem and augmentin exhibited opposing effects with reduced growth of isolates from symptomatic patients and a significant increase in asymptomatic isolates. Whereas, vancomycin-treated cultures had no difference in the growth of Blastocystis sp. ST3 isolates from symptomatic and asymptomatic patients. Isolates from symptomatic and asymtomatic patients had 6 and 2 distinct bacterial species identified with Proteus mirabilis as the common bacteria among both types of isolates. Morphologically, Blastocystis sp. ST3 cultures exposed to meropenem and augmentin demonstrated an increase in pre-cystic forms. These findings demonstrate the effects of accompanying bacteria on the growth of Blastocystis sp. ST3 that could translate into clinical manifestations observed among Blastocystis sp.-infected patients.
Trichomonas vaginalis, a flagellated protozoan parasite, is commonly found in the genitourinary tract of humans. Its mode of reproduction has always been reported to be binary fission. The high parasite numbers seen in a relatively short period in in vitro cultures led us to believe that there must be other modes of reproduction. The present study for the first time provides transformational evidence at the ultrastructural level seen in tropohozoites of T. vaginalis undergoing a multiple asexual mode of reproduction. The findings show that the single cell with a nucleus is capable of dividing to as many as eight nuclei within the cytoplasmic body. Before the commencement of division, the nucleus remained round or ovoid in shape with condensed chromatin masses and only a few endoplasmic reticula surrounding the nucleus. During the division, the nucleus started to elongate and become irregular in shape with visible chromatin masses condensing with the accumulation of numerous endoplasmic reticula. Nuclear division gave rise to as many as eight nuclei within a cell, which could be seen to be connected by numerous endoplasmic reticula. In addition, a high number of hydrogenosomes and vacuoles can be seen in multinucleated T. vaginalis compared with single nucleated T. vaginalis. This study confirms that multiple modes of nuclear division do exist in T. vaginalis and are a precursor to progeny formation.
Caballeria liewi Lim, 1995, uses adhesive secretions from the head organs and posterior secretory systems to assist in locomotion and attachment. Ultrastructural investigations show that the head organs of C. liewi consist of three pairs of antero-lateral pit-like openings bearing microvilli and ducts leading from two types of uninucleated gland cells (located lateral to the pharynx), one type producing rod-like (S1) bodies with an electron-dense matrix containing less electron-dense vesicles and the second type producing oval (S2) bodies with a homogeneous electron-dense matrix. Interlinking band-like structures are observed between S1 bodies and between S2 bodies. S1 body is synthesised in the granular endoplasmic reticulum, transported to a Golgi complex to be packaged into vesicles and routed into ducts for exudation. The synthesis of the S2 body is unresolved. Haptoral secretions manifested externally as net-like structures are derived from dual electron-dense (DED) secretory body produced in the peduncular gland cells. The DED body consists of a less electron-dense oval core in a homogeneous electron-dense matrix. On exocytosis into the pyriform haptoral reservoir, DED bodies are transformed into a secretion with two types of inclusions (less electron-dense oval and electron-dense spherical inclusions) in an electron-dense matrix. The secretions are further transformed (as small, oval, electron-dense bodies) when transported to the superficial anchor grooves, and on exudation into the gill tissues, the secretions become an electron-dense matrix. Secretory bodies associated with uniciliated structures, anchor sleeves and marginal hooks are also observed.
The de novo biosynthesis of phosphatidylcholine and phosphatidylethanolamine in Entamoeba histolytica is largely dependent on the CDP-choline and CDP-ethanolamine pathways. Although the first enzymes of these pathways, EhCK1 and EhCK2, have been previously characterized, their enzymatic activity was found to be low and undetectable, respectively. This study aimed to identify the unusual characteristics of these enzymes in this deadly parasite. The discovery that EhCKs prefer Mn2+ over the typical Mg2+ as a metal ion cofactor is intriguing for CK/EK family of enzymes. In the presence of Mn2+, the activity of EhCK1 increased by approximately 108-fold compared to that in Mg2+. Specifically, in Mg2+, EhCK1 exhibited a Vmax and K0.5 of 3.5 ± 0.1 U/mg and 13.9 ± 0.2 mM, respectively. However, in Mn2+, it displayed a Vmax of 149.1 ± 2.5 U/mg and a K0.5 of 9.5 ± 0.1 mM. Moreover, when Mg2+ was present at a constant concentration of 12 mM, the K0.5 value for Mn2+ was ~ 2.4-fold lower than that in Mn2+ alone, without affecting its Vmax. Although the enzyme efficiency of EhCK1 was significantly improved by about 25-fold in Mn2+, it is worth noting that its Km for choline and ATP were higher than in equimolar of Mg2+ in a previous study. In contrast, EhCK2 showed specific activity towards ethanolamine in Mn2+, exhibiting Michaelis-Menten kinetic with ethanolamine (Km = 312 ± 27 µM) and cooperativity with ATP (K0.5 = 2.1 ± 0.2 mM). Additionally, we investigated the effect of metal ions on the substrate recognition of human choline and ethanolamine kinase isoforms. Human choline kinase α2 was found to absolutely require Mg2+, while choline kinase β differentially recognized choline and ethanolamine in Mg2+ and Mn2+, respectively. Finally, mutagenesis studies revealed that EhCK1 Tyr129 was critical for Mn2+ binding, while Lys233 was essential for substrate catalysis but not metal ion binding. Overall, these findings provide insight into the unique characteristics of the EhCKs and highlight the potential for new approaches to treating amoebiasis. Amoebiasis is a challenging disease for clinicians to diagnose and treat, as many patients are asymptomatic. However, by studying the enzymes involved in the CDP-choline and CDP-ethanolamine pathways, which are crucial for de novo biosynthesis of phosphatidylcholine and phosphatidylethanolamine in Entamoeba histolytica, there is great potential to discover new therapeutic approaches to combat this disease.
The fact whether Blastocystis hominis can invade has always been in question. Apart from a few sporadic studies such as that done on gnotobiotic guinea pigs which showed surface invasion and mucosal inflammation of the host's intestine caused by B. hominis infection, no real documentation of invasion has been proven. Studies have shown that hyaluronidase is secreted during the penetration into the host's skin and gut by nematode parasites. Hyaluronidase activity in protozoa namely Entamoeba histolytica has also been described previously. This study attempts to determine hyaluronidase in urine samples of B. hominis-infected rats. The presence of hyaluronidase in urine provides an indirect evidence of invasion by B. hominis into colonic epithelium causing the degradation of extracellular matrix proteins namely hyaluronic acid (HA). HA is depolymerized by hyaluronidase which may be used by organisms to invade one another. In this study, the levels of urinary hyaluronidase of Sprague-Dawley rats infected with B. hominis were monitored for 30 days. Hyaluronidase levels in the infected rats were significantly higher on days 28 and 30 compared to the day before inoculation (P < 0.01 and P < 0.05, respectively). During this stage, parasitic burden in infected stools was also at a high level. Proinflammatory cytokines, interleukin-6 and interleukin-8, were also significantly higher (P < 0.05) in the serum of infected rats. The study demonstrates that since no other pathogen was present and that amoeboid forms of the parasites have been shown to exist previously, the elevated levels of hyaluronidase in this preliminary finding suggests that the organism is capable of having invasion or penetration activity in the hosts' intestine.
The objective of this study was to assess the physico-chemical parameters and waterborne parasites in selected recreational lakes from Malaysia. Samples were collected from seven stations of Recreational Lake A (RL-A) and six stations of Recreational Lake B (RL-B). The samples were processed to detect the presence of Giardia spp. and Cryptosporidium spp. using immunomagnetic separation kit, helminth eggs or ova by bright field microscopy and Acanthamoeba spp. by cultivation in non-nutrient agar. Chemical parameters such as ammonia, chlorine, fluoride, nitrate and nitrite and physical parameters such as dissolved oxygen, electrical conductivity, pH, salinity, temperature and total dissolved solid were also measured. Both lakes were freshwater with salinity ranging from 0.05 to 0.09 ppt. Most stations of these lakes were contaminated with Cryptosporidium spp., Giardia spp., Ascaris spp. and hookworm. Schistosoma spp. was found in RL-B only, while Acanthamoeba spp. was found in all stations. Of all sampling sites, station 5 of RL-B is the most contaminated. Linear regression and correlation analysis revealed that Giardia spp. and Schistosoma spp. showed a significant negative correlation with turbidity (p
Gonadectomized male albino rats aged 7 weeks were given 1.5 mg/kg testosterone propionate daily and inoculated with 50 third-stage larvae of Angiostrongylus malaysiensis. The treatment significantly increased the number of larvae and adult worms recovered from the brain and pulmonary arteries, respectively, and the rats exhibited smaller thymus glands. The total numbers of leukocytes, monocytes, neutrophils, and especially eosinophils increased significantly post-infection, but the counts were higher in the untreated infected controls. Presumably, immunosuppressive effects of testosterone may at least partly be responsible for the higher loads of A. malaysiensis worms found in male rats as compared with females in the field.