We have isolated a novel protein kinase cDNA, PfPK6, by differential display RT-PCR (DDRT-PCR) of mRNA obtained from different asexual erythrocytic stages of Plasmodium falciparum, which shows sequence similarity to both cyclin-dependent kinase (CDK) and mitogen-activated protein kinase (MAPK) family members. The 915 bp open reading frame (ORF) is interrupted by seven introns and encodes a 305-...

According to the World Health Organization (WHO), Plasmodium falciparum is the deadliest parasite among all species. This parasite possesses the ability to sense molecules, including melatonin (MEL) and cAMP, and modulate its cell cycle accordingly. MEL synchronizes the development of this malaria parasite by activating several cascades, including the generation of the second messenger cAMP. Th...

DNA sequences of three 18S rRNA gene alleles present in trophozoites obtained before and after therapy for Acanthamoeba keratitis substantiate a previous report that the infection was due to a single Acanthamoeba strain. Thus, the possibility that propamidine resistance which developed during therapy was due to a mixed infection was ruled out.

The purpose was to identify the prevalence of naked amoebae in tap water in south Florida to ascertain the risk of amoebal infections of the cornea in contact lens wearers. Over the course of a 2-year period, water samples were collected from sites throughout Broward, Palm Beach, and Dade counties, Florida. The presence of amoebae in samples was based on an enrichment cultivation method appropr...

Two numerically minor components of Plasmodium falciparum prevalence--gametocytaemia and trophozoite densities greater than 99/500 white blood cells--displayed an annual cycle that reflected the seasonal abundance of infective Anopheles dirus at a hyperendemic focus in Thailand, even though the gross monthly prevalence for combined ages remained stable. Gametocyte prevalence rose more than 300%...

Giardia trophozoites are polyploid and have five chromosomes. The chromosome homologues demonstrate considerable size heterogeneity due to variation in the subtelomeric regions. We used clones from the genome project with telomeric sequence at one end to identify six subtelomeric regions in addition to previously identified subtelomeric regions, to study the telomeric arrangement of the chromos...

Basic aspects of cell biology of Pneumocystis carinii are reviewed with major emphasis on its life cycle and the structural organization of the trophozoites and cyst forms. Initially considered as a protozoan it is now established that Pneumocystis belongs to the Fungi Kingdom. Its life cycle includes two basic forms: (a) trophozoites, which are haploid cells that divide by binary fission and m...

Homologous recombination (HR) has not been demonstrated in the parasitic protists Entamoeba histolytica or Entamoeba invadens, as no convenient method is available to measure it. However, HR must exist to ensure genome integrity, and possible genetic exchange, especially during stage conversion from trophozoite to cyst. Here we show the up regulation of mitotic and meiotic HR genes in Entamoeba...

A case of atypical Plasmodium vivax malaria is presented. The clinical follow-up has allowed to characterize three consecutive malaria clinical episodes within one year. At the first attack, 39% of the infected red blood cells were parasitized by gametocytes. Furthermore, rare crisis forms, exceptional "pseudoparthenogenesis" forms, a few equatorial trophozoites, malaria pigment-containing leuc...

The mobility patterns of four enzymes using cultured trophozoites of Entamoeba histolytica were examined by electrophoresis. By this means the stocks of amoebae isolated from male homosexuals were characterised into zymodemes. No amoebic stock isolated corresponded to a pathogenic zymodeme.