Ca(2+)-signaling pathways and intracellular Ca(2+) channels are present in protozoa. Ancient origin of inositol 1,4,5-trisphosphate receptors (IP3Rs) and other intracellular channels predates the divergence of animals and fungi as evidenced by their presence in the choanoflagellate Monosiga brevicollis, the closest known relative to metazoans. The first protozoan IP3R cloned, from the ciliate P...

ELECTRON-MICROSCOPIC STRUCTURE OF PROTOZOA. By Dorothy R. Pitelka. New York, The Macmillan Co., 1963. x, 269 pp. $12.50. This volume is the most recent appearance in the Zoology Division of the International Series of Monographs on Pure and Applied Biology. It is a review of the literature on the fine structure of protozoa published through June, 1961. A review of such a diversity of animals in...

Secretory processes play an important role on the biology and life cycles of parasitic protozoa. This review focus on basic aspects, from a cell biology perspective, of the secretion of (a) micronemes, rhoptries and dense granules in members of the Apicomplexa group, where these organelles are involved in the process of protozoan penetration into the host cell, survival within the parasitophoro...

Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control...

We propose a general theory of clonal reproduction for parasitic protozoa, which has important medical and biological consequences. Many parasitic protozoa have been assumed to reproduce sexually, because of diploidy and occasional sexuality in the laboratory. However, a population genetic analysis of extensive data on biochemical polymorphisms indicates that the two fundamental consequences of...

Parasitic protozoa are major threats to human health affecting millions of people around the world. Control of these infections by the host immune system relies on a myriad of immunological mechanisms that includes both humoral and cellular immunity. CD8+ T cells contribute to the control of these parasitic infections in both animals and humans. Here, we will focus on the CD8+ T cell response a...

Background: Intestinal protozoa transmitted by food are the most common opportunistic parasites among the HIV+/AIDS patients. As, there is no report about prevalence of food-borne intestinal parasites in such patients in Yazd, so this study was performed to determine the prevalence of intestinal protozoa in the HIV+/AIDS patients in comparison with HIV- individuals. Methods: A case-control stu...

Intact, metabolically active rumen protozoa prepared by gravity sedimentation and washing in a mineral solution at 10 to 15 degrees C had comparatively low proteolytic activity on azocasein and low endogenous proteolytic activity. Protozoa washed in 0.1 M potassium phosphate buffer (pH 6.8) at 4 degrees C and stored on ice autolysed when they were warmed to 39 degrees C. They also exhibited low...

A number of protozoa are known to cause bowel disease in humans. Here the author discusses clinical features, diagnosis and management those more likely be encountered by doctors temperate zones.

Trophic interactions within the plankton of the lowland River Meuse (Belgium) were measured in spring and summer 2001. Consumption of bacteria by protozoa was measured by monitoring the disappearance of H-thymidine-labelled bacteria. Metazooplankton bacterivory was assessed using 0.5-μm fluorescent microparticles (FMPs), and predation of metazooplankton on ciliates was measured using natural ci...