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PubMedDate not supplied

Antibodies to gut protozoa in commercial immunoglobulin preparations.

Using parasite agglutination, indirect immunofluorescence, enzyme-linked immunosorbent assay, and immunoblotting, Giardia lamblia specific antibody was detected in 5 commercially available immunoglobulin (IgG) preparations. IgG antibodies to Entamoeba histolytica were either present in very low titre or were absent. Immunoblotting showed that anti-G. lamblia antibodies were detected towards a range of Giardia proteins, 25-200 kDa. These findings raise the possibility that pooled human IgG preparations could be evaluated in the treatment of chronic giardiasis which is refractory to conventional therapy.

Agglutination↗
PubMed1976

DNA of ciliated protozoa: DNA sequence diminution during macronuclear development of Oxytricha.

We have measured the reassociation kinetics of DNA from the micronucleus and from the macronucleus of the hypotrichous ciliate Oxytricha. The micronuclear DNA reassociates with at least a two-component reaction, indicating the presence of both repeated and non-repeated sequences. The kinetic complexity of micronuclear non-repeated DNA is in the range of 2 to 15 X 10(11) daltons; the haploid DNA content of the micronucleus is 4 X 10(11) daltons (0.66 pg), measured microspectrophotometrically. The DNA of the macronucleus reassociates as a single second-order reaction, with a kinetic complexity of 3.6 X 10(10) daltons. A comparison of the kinetic complexities of micronuclear and macronuclear DNAs suggest a 5 to 30 fold reduction in DNA sequence complexity during the formation of a macronucleus from a micronucleus. Macronuclear DNA is in pieces with an average molecular weight of 2.1 X 10(6) daltons. Since the kinetic complexity of macronuclear DNA is 3.6 X 10(10) daltons, the macronucleus must contain about 17,000 different kinds of DNA pieces. Each macronucleus contains 3.5 X 10(13) daltons (58 pg) of DNA, indicating that each sequence must be present about 1000 times per macronucleus or 2000 times per cell.

Animals↗
PubMed1995

Intracellular calcium transients in suctorian protozoa (Trichophrya spp.): correlation with spontaneous tentacle contractions.

The luminescent photoprotein aequorin was used to measure intracellular free Ca2+ in three species of suctorian protozoon, Trichophrya riederi, Trichophrya collini and Trichophrya rotunda. Resting [Ca2+]i ranged from about 75-110 nM, and was unaffected by a change in temperature of the perfusate. Spontaneous Ca2+ transients were observed in all three species, with peak amplitudes ranging from 100-600 nM. In T. riederi and T. rotunda, three categories of transient (small, intermediate, large) were recorded; T. collini displayed only small transients. In both T. riederi and T. collini, raising the temperature from 5 degrees to 26 degrees C led to an increase in the frequency of transients. Furthermore, in T. riederi, large transients occurred only at the higher temperature. The frequency of spontaneous contractions of the tentacles of T. riederi was also temperature-dependent. Increasing the temperature over the range 5-26 degrees C led to a concomitant increase in contraction frequency and a decrease in mean tentacle length. The possible mechanisms of spontaneous Ca2+ transient generation and their role in the control of contraction are discussed.

Aequorin↗
PubMed1983

Ciliated Protozoa in marine pollution studies. A conspectus.

The ecological role of the marine ciliates is discussed with reference to the interaction of this group with contaminants. While the ciliates may be of some value in routine screening of potential toxins, simple laboratory bioassays are unlikely to be of predictive value in assessing threats to the marine environment. There is some evidence that ciliates may take part in the transfer and transformation of potential pollutants. Further field and laboratory studies are required in order to identify and quantify the role of ciliates in these processes.

Animals↗
PubMed1990

Parasitic protozoa in drinking water.

The importance of treating public water supplies to destroy pathogenic micro-organisms has long been recognized. In the past, emphasis has been laid on bacteria, but the hazard posed by certain protozoan parasites is being increasingly recognized. Some of these present a particularly serious problem in that they can survive chlorination and most purification treatments regarded by international standards, as giving adequate protection to the consumer.

Animals↗
PubMed1980

Characteristic proteins of micronemes and dense granules from Sarcocystis tenella zoites (Protozoa, Coccidia).

A subcellular fractionation procedure has been developed, which allowed the recovery of purified fractions of micronemes, dense granules and pellicles from Sarcocystis tenella zoites. As expected, sodium dodecyl sulphate polyacrylamide gels electrophoresis of the pellicles showed a fairly heterogenous protein content. In contrast, only one major omponent (42 000) daltons) was found in the dense granules, whereas two major bands (20 000 and 22 000 daltons) were observed for the micromemes. These characteristic proteins were also major components of the whole zoite and might have important functions in the physiology of the organism.

Animals↗
PubMed1981

The enzymes of pyrimidine biosynthesis in a range of parasitic protozoa and helminths.

The activities of carbamoylphosphate synthase, aspartate transcarbamoylase, dihydroorotase, orotate phosphoribosyl transferase and orotidine-5'-phosphate decarboxylase, five of the six enzymes of pyrimidine biosynthesis, have been measured in Crithidia fasciculata, Trypanosoma cruzi, Leishmania major, Trichomonas vaginalis, Eimeria tenella, Toxoplasma gondii, Plasmodium berghei, Fasciola gigantica, Schistosoma mansoni, Hymenolepis diminuta, Nippostrongylus brasiliensis and Trichuris muris. The majority of organisms contained all five enzyme activities. However, in T. vaginalis only carbamoylphosphate synthetase activity and in E. tenella only orotate phosphoribosyl transferase and orotidine-5'-phosphate decarboxylase activities could be detected. It appears therefore that the ability to synthesise pyrimidines by the de novo route is probably both common and widespread amongst parasitic organisms.

Animals↗
PubMed1986

An antigenic determinant common to both mouse red blood cells and several membrane proteins of the parasitic protozoa Babesia rodhaini.

Four membrane proteins of Babesia rodhaini have been identified by monoclonal antibodies. These proteins are differentiated by serological criteria and by tryptic peptide maps but contain common antigenic determinants. In vitro translation of parasite polyadenylated RNA followed by immunoprecipitation demonstrates that these common determinants are located within the primary sequence of the protein and do not result from post-translational modification. Part of the common amino acid sequence of these proteins is also present within a protein found in mouse red blood cells. Such common structures could potentially play an important role in the host-parasite relationship. The presence of sequence homology within a group of proteins from Babesia rodhaini could be further evidence for the atypical genetic rearrangements proposed to take place within Babesia species.

Amino Acid Sequence↗