bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of peptidases inTrypanosoma cruziepimastigotes using chromogenic and fluorogenic substrates
Authors: Healy N. , Greig S. , Enahoro H. , Roberts H. , Drake L. , Shaw E. , Ashall F. 
Published: June 2009

SUMMARYDetergent extracts ofTrypanosoma cruziepimastigotes catalysed the hydrolysis of a range of amino-acyl and peptidyl p-nitro-anilides and aminomethylcoumarins. At least three enzymes were detected that cleave Z–Phe–Arg–MCA. Two of these were optimally active at alkaline pH, the other at pH 4·0. Of the two enzymes with alkaline pH optima, one was a cysteine peptidase and was unable to cleave Bz–Arg–MCA readily, whilst the other cleaved Bz–Arg–MCA and was inhibited by diisopropyl fluorophosphate. The acidic enzyme was similar to cathespin L of other eukayrotes with respect to its pH profile, substrate-specificity and inhibitor-sensitivity. Evidence was presented that epimastigotes contain a cysteine-type dipeptidyl aminopeptidase, one or more aminopeptidases, and a serine peptidase that cleaves Boc–Ala–Ala–pNA. Digitonin solubilization of the activities from cells supports the hypothesis that the cathespin L-like enzyme and the dipeptidyl aminopeptidase are lysosomal, whilst the Bz–Arg–MCA hydrolase, the aminopeptidases and the Boc–Ala–Ala–pNA serine peptidase are cytosolic.
Nematodirus battus: scanning electron microscope studies of the duodenal mucosa of infected lambs
Authors: Martin Jean , Lee D. L. 
Published: June 2009

SUMMARYLambs given 60000 third-stage larvae of Nematodirus battus were killed on days 16, 20, 22, 24 and 32 of the infection and the duodenal mucosa was examined by scanning electron microscopy (SEM). On day 16 of the infection the villi were long and finger-like and, although goblet cells were visible, the surface of the villi was not extensively folded, as is the surface of villi of uninfected control animals. By day 20 of the infection the villi had been reduced to flattened, plate-like structures or had formed low, irregular-shaped ridges. On this day of the infection the nematodes appeared to be enclosed by mucus-like material. As the infection progressed the intestinal damage was repaired, so that, by day 24 of the infection, the surface of the intestine was covered by short, smooth, finger-like projections and, by day 32 of the infection, the morphology of the intestine was somewhat similar to that of the control lamb. The possible role of villus atrophy and of mucus in the rejection of N. battus from the intestine is discussed.
Enzyme polymorphism of freshwater fish trypanosomes and its use for strain identification
Authors: Zajíček P. 
Published: June 2009

SUMMARYSixteen strains of trypanosomes isolated from the blood of 10 freshwater fish species (all but one from South Bohemia) were characterized by enzyme analysis using dise electrophoresis in 5% polyacrylamide gel. Six enzymes were selected: ADH, LDH, MDH, ME, G6PDH and GPI. The most variable were ADH and LDH, whereas MDH, G6PDH and GPI showed the same pattern in all strains analysed. Cluster analysis indicated a very high degree of similarity among strains, even those isolated from phylogenetically distant hosts. Moreover, no correlation between enzyme pattern and host species was found.
The transition from an aerobic to an anaerobic energy metabolism in transforming Schistosoma mansoni cercariae occurs exclusively in the head
Authors: Horemans A. M. C. , Tielens A. G. M. , Van Den Bergh S. G. 
Published: June 2009

SUMMARYIt has been shown that in intact cercariae of Schistosoma mansoni in water, both head and tail had an identical, aerobic energy metabolism. As long as the environment was water, glucose was mainly degraded to carbon dioxide by both head and tail whether or not these two were still connected to each other. Transfer of intact cercariae into a simple salt medium supplemented with glucose resulted in a very rapid transition towards a more anaerobic energy metabolism: the production of lactate and pyruvate increased, whereas the production of carbon dioxide remained more or less constant. A concomitant rise in temperature to 37°C was not essential for this biochemical transition, but made it more pronounced. Experiments on isolated cercarial bodies and tails in a transforming medium demonstrated that the tails oxidized glucose to carbon dioxide, whereas bodies produced mainly pyruvate and lactate. The results showed that the metabolic transition towards a more anaerobic energy metabolism occurred only in the head and not in the tail of the cercariae. Loss of the tail was shown not to be a pre-requisite for this transition, nor did it by itself trigger a metabolic switch in the resulting cercarial body.
Kronbrogia pugettensis sp. nov. (Neorhabdocoela: Fecampiidae), an endoparasitic turbellarian infesting the shrimp Heptacarpus kincaidi (Rathbun), with notes on its life-history
Authors: Shinn G. L. , Christensen A. M. 
Published: June 2009

SUMMARYThe morphology of Kronborgia pugettensis sp. nov., an endoparasite from the haemocoele of the caridean shrimp Heptacarpus kincaidi is described from specimens collected in the San Juan Island region of the western coast of North America. Members of this species are unisexual as are other members of the genus, but only females were found. An ootype and a type of accessory reproductive gland not known from other Kronborgia spp, are described, but they are probably present in other members of the genus. The life-history is similar to that of other Kronborgia spp. After the female reaches maturity, it emerges from the host and secretes a tubiform cocoon around itself and deposits its egg capsules within it. Embryogenesis lasts about 4 months. A free-swimming larva locates the new host, attaches to its exterior, and secretes a cyst around itself. It then penetrates through the exoskeleton to reach the haemocoele. K. pugettensis is easily distinguished from other members of the genus by the shape of the cocoon, type of host, and geographic distribution. This is the second species of fecampiid described from North America, but several undescribed species are known to exist from their cocoons.
A comparative study of the succinate dehydrogenase–fumarate reductase complex in the genusTrichinella
Authors: Rodriguez–Caabeiro F. , Criado–Fornelio A. , Jimenez–Gonzalez A. 
Published: June 2009

SUMMARYSuccinate dehydrogenase and fumarate reductase activities from a participate fraction of 4 isolates of the supposed ‘species’ ofTrichinella, T. spiralis, T. pseudospiralis, T. nativaandT. nelsonihave been determined using spectrophotometric methods. The ‘in vitro’ effect of the anthelmintics thiabendazole, mebendazole and ivermectin on succinate dehydrogenase and fumarate reductase activities from the above isolates is also described. The significance of the results is discussed in the context of the controversy that surrounds speciation of the genusTrichinella.
Monosaccharide composition of the surface glycoprotein antigens ofTrypanosoma brucei
Authors: Allsopp B. A. , Njogu A. R. 
Published: June 2009

Evidence has been adduced that the surface antigens ofTrypanosoma bruceisubgroup are a group of glycoproteins having D-galactose, D-mannose and D-glucosamine as monosaccharide components.There was considerable variation in the number of antigen components, and their relative amounts, as revealed by isoelectric focusing on polyacrylamide gel. The relevance of these variations to the adaptation theory of antigenic variation in trypanosomes is discussed.
The distribution of larval Aspiculuris tetraptera Schulz during a primary infection in Mus musculus, Rattus norvegicus and Apodemus sylvaticus
Authors: Behnke Jerzy M. 
Published: June 2009

The larvae of Aspiculuris tetraptera were found in the mid-colon of mice within hours of infection. When the colon was divided into 10 equal sections the larvae were mainly found in sections 5, 6 and 7 during the first 6 days of the infection. The worms entered the crypts of Lieberkühn in this region on day 1 and remained there until day 4 or 5. After this time they left the crypts and returned to the lumen of the colon. On day 7 the worms emigrated anteriorly and thereafter were recovered only from the proximal region of the colon (sections 1–4), although in heavier infections a few larvae remained in the mid-colon.The initial establishment site was the same in both Rattus norvegicus and in Apodemus sylvaticus, but an infection with A. tetraptera in the abnormal hosts, R. norvegicus and A. sylvaticus, was characterized by less than 7% of the inoculum becoming established, a slower rate of growth and a wider distribution centering around the preferred site. The small number of established larvae was lost from the rat before day 12 and from A. sylvaticus before day 8, whereas larvae persisted in laboratory mice for a longer period.
Effects of dietary carbohydrate on the nutritional physiology and blood sugar level of Trichoplusia ni parasitized by the insect parasite, Hyposoter exiguae
Authors: Thompson S. N. 
Published: June 2009

SUMMARYThe effects of parasitization by Hyposoter exiguae on the nutritional physiology of Trichoplusia ni were influenced by the dietary sucrose level. The results confirmed that host nutrition plays a significant role in the manifestation of parasitic infection during the insect parasite-host association. Increased dietary sucrose level resulted in an increase in haemolymph trehalose concentration in both control and parasitized insects, but the increase was greater in the latter group. However, when the sucrose level was increased without energetic compensation and the dietary casein level was maintained constant, the haemolymph trehalose concentration was affected very little in unparasitized individuals but was markedly elevated in parasitized hosts. This result suggests that the de novo synthesis of carbohydrate in parasitized T. ni may not be regulated by dietary sugar intake.
Schistosoma mansoni: dynamics of migration through the vascular system of the mouse
Authors: Wilson R. A. , Coulson Patricia S. 
Published: June 2009

SUMMARYAutoradiography of compressed mouse tissues has been used to estimate the numbers of Se-labelled schistosomula present in different mouse organs. Day 7 parasites extracted from the lungs of donor mice were delivered by injection to the lungs, systemic organs and liver of recipient mice as a discrete pulse. The numbers detected in various locations with time post-injection were then used to analyse the dynamics of intravascular migration. Approximately 98% of cercaria-associated label was lost during the first 14 days of parasite life, two-thirds of this in the first 7 h post-infection. Nevertheless, 99–113% of schistosomula could be detected 30 min post-injection into the locations chosen. The efficiency of the parasite delivery system was 95%. The time required for the number of foci in the lungs to decline to 50%, after injection of parasites via the femoral vein, was 55 h. Adjustment of this data to allow for parasites returning to the lungs after passage round the systemic vasculature gave a value of 30–35 h for the true mean time of lung transit. The distribution of parasites to systemic organs after their exit from the lungs was proportional to the fractional distribution of cardiac output. The probability (P) of a schistosomulum being distributed to splanchnic beds was estimated at 0·32 and itsPof being trapped in the hepatic portal distributaries within the liver as 0·72–0·86. On this basis, the entire hepatic portal population of adult schistosomes would be recruited during 2–3 circuits of parasites around the pulmonary-systemic vasculature. The mean transit time of schistosomula through intestinal capillaries was 6·5 h whilst that through other systemic organs combined (muscles, kidneys, brain, etc) was 16 h, considerably more rapid than lung transit. The time taken for schistosomula to pass between organs, in arterial and venous blood, was shown to be less than 30 min in both cases (probably much less).
Detection of linkage disequilibrium in Trypanosoma brucei isolated from tsetse flies and characterized by RAPD analysis and isoenzymes
Authors: Stevens J. R. , Tibayrenc M. 
Published: June 2009

SUMMARYThis study analyses the different populations of Trypanosoma brucei spp. which may coexist within the midgut of wild tsetse flies (Stevens et al. 1994). Cloned trypanosome populations characterized by multilocus enzyme electrophoresis (MLEE) were further analysed by the random amplified polymorphic DNA (RAPD) technique, allowing detection of genetic variation at a finer level than that possible by MLEE. Genetic distance matrices derived from the results of each of the two biochemical methods were calculated and compared using a computer program based on the method of Mantel (1967). The observed correlation was used to investigate the degree of linkage disequilibrium (LD) in the data, association between unrelated polymorphic markers providing a measure of the departure from panmixia. The potential of each biochemical method to detect linkage was evaluated by an extended Mantel test. The MLEE/RAPD correlation test evidenced significant LD within the population, suggesting a predominantly clonal method of reproduction for these West African trypanosomes. Analysis of RAPD data by the extended Mantel test also showed significant LD, while the results with MLEE data were less conclusive, providing an indication of the relative potential of the two techniques to detect fine genetic variation.
203Hg and other gamma-emitting radio-isotopes as labels for Dirofilaria immitis microfilariae
Authors: Lengemann F. W. , Grieve R. B. , Chmielewicz M. , Georgi J. R. 
Published: June 2009

SUMMARYThe in vitro uptake of gamma-emitting radionuclides by microfilariae of Dirofilaria immitis was investigated. Radionuclides tested were 133Ba, 207Bi, 82Br, 109Cd, 51Cr, 60Co, 59Fe, 203Hg, 125I, 54Mn, 32P, 125Sb, 75Se, and 65Zn. Only 207Bi, 59Fe, 203Hg, 54Mn, and 46Sc showed more than 2% of the available radioactivity to bind to the microfilariae. When tested for retention in vitro only 203Hg showed retention levels approaching 90%. Moreover, when dimethyl suiphoxide was incorporated into the medium at levels of 1% (v/v) the uptake of 203Hg could be increased by 3–5 times; no other radio-isotope tested responded in this manner. The uptake of 203Hg was directly related to temperature and time of incubation. Mercury, as mercuric chloride, was toxic to the microfilariae and respresents an impediment to the incorporation of high levels of 203Hg in microfilariae.
Trichuris trichiurainfection and cognition in children: results of a randomized clinical trial
Authors: Simeon D. T. , Grantham-McGregor S. M. , Wong M. S. 
Published: June 2009

SUMMARYThe effects of mild to moderate infections ofTrichuris trichiuraon cognitive functions were investigated in Jamaican children aged 7 to 10 years. In all, 189 infected children and 100 uninfected classmates were studied. The infected children were randomly assigned to receive treatment (albendazole) or a placebo. All children were given cognitive tests on enrolment and 14 weeks later. These included verbal fluency (generation of ideas), digit span (working memory), number choice (speed of processing of visual stimuli), visual search (sustained attention) and a French Vocabulary test (paired-associate learning). At baseline, the infected children had lower scores than the uninfected ones in fluency (P= 0·01), search (P= 0·02) and French (P= 0·01). Treatment effects were examined among infected children and there was no significant treatment effect for any of the tests. However, there was a significant treatment by weight-for-age interaction in fluency (P < 0·05). The children with low weight-for-age (Z-score < – 1) improved with treatment while there was no improvement with treatment among the other children. We concluded that treatment of children with mild to moderateT. trichiurainfections using albendazole produces little benefit in cognition if they are adequately nourished; however, undernourished children are more likely to benefit.
Endotoxins in the blood and cerebrospinal fluid of patients with African sleeping sickness
Authors: Pentreath V. W. , Alafiatayo R. A. , Crawley B. , Doua F. , Oppenheim E. A. 
Published: June 2009

SUMMARYEndotoxin levels were measured in the blood and cerebrospinal fluid (CSF) of control individuals and 2 groups of patients with African sleeping sickness. Endotoxin levels were markedly elevated in the blood (infected groups mean endotoxin values 40·2 pg/ml and 53·8 pg/ml, compared to control 11·6 pg/ml, P < 0·0001 for both increases) and CSF (infected groups mean endotoxin values 45·8 pg/ml and 50·1 pg/ml compared to control 6·3 pg/ml, P < 0·0001 for both increases) of the patients. The levels were reduced 6 weeks following different drug treatments in the 2 groups (blood levels to mean 33·8·pg/ml and 28·5 pg/ml; CSF levels to 37·4 pg/ml and 27·0 pg/ml). The blood endotoxin values correlated with the CSF values before treatment (r = 0·74 and 0·57 for the 2 groups; P < 0·0001 for both) and after treatment (r = 0·57 and 0·56 for the 2 groups; P < 0·0001 for both). It is concluded that raised endotoxin equilibrates in the blood and CSF compartments, and may contribute significantly to the pathology of sleeping sickness.
Cytoadherence-related homologous motifs inPlasmodium falciparumantigen Pf155/RESA and erythrocyte band 3 protein
Authors: Iqbal J. , Siddique A. B. , Ahlborg N. , Perlmann P. , Berzins K. 
Published: June 2009

SUMMARYCytoadherence ofPlasmodium falciparum-infected erythrocytes plays an important role in the pathogenesis of cerebral malaria. The identity of cell surface molecules on parasitized erythrocytes involved in cytoadherence is of great interest to understand the molecular basis of this mechanism. Peptide sequences derived from exofacial loops of the erythrocyte antigen band 3 from parasitized erythrocytes have previously been shown to inhibit cytoadherence. We now report that a non-repeated region of Pf155/RESA (residues 213–218) contains a hexapeptide motif being highly homologous to cytoadherence inhibitory sequences from band 3. Synthetic peptides containing the hexapeptide motif of Pf155/RESA inhibited the binding ofP.falciparum-infected erythrocytes to melanoma cellsin vitro. Furthermore, individuals residing in malaria-endemic areas have antibodies reactive with epitopes involving these motifs in band 3 and in Pf155/RESA.
Hymenolepis diminuta-induced fecundity reduction may be caused by changes in hormone binding to Tenebrio molitor ovaries
Authors: Webb T. J. , Hurd H. 
Published: June 2009

SUMMARYAspects of vitellogenesis, known to be controlled by juvenile hormone, are adversely affected by Hymenolepis diminuta infection of Tenebrio molitor, in spite of circulating titres of the hormone remaining unchanged. It has therefore been proposed that juvenile hormone binding is disrupted at the tissue site level. Juvenile hormone III binding sites were located in the nuclear, microsomal and post-microsomal supernatant fractions of the follicle cells of Tenebrio molitor. When JH-III binding was quantified for both control and Hymenolepis diminuta-infected beetles, binding in the nucleus and cytosol were found to be largely unaffected. However, microsomal binding was severely disrupted; on days 3 and 6 post-infection, binding was greatly diminished, on day 9 post-infection, binding was slightly reduced and, by day 15, binding was ‘restored’ to that of control insects. Using follicle cell microsomes at day 3 post-infection, previous Scatchard analysis revealed the presence of at least two JH-III binding sites. The first is of higher affinity, Kd = 5·3 x 10·5 x 10−11 mol/mg protein and the second of lower affinity Kd = 7·7 x 10−7 M, Bmax = 9·75 x 10−11 mol/mg protein. A comparison with microsomal binding parameters of follicle cells from non-infected Tenebrio indicated that although the Bmax values were unchanged, the Kd value of the higher affinity site was increased by approximately 5-fold. These data are indicative of a parasite-induced competitive binding inhibitor.
Identification of isolate-specific proteins on sorbitol-enriched Plasmodium falciparum infected erythrocytes from Gambian patients
Authors: Aley S. B. , Sherwood J. A. , Marsh K. , Eldelman O. , Howard R. J. 
Published: June 2009

SUMMARYWe have compared the surface radio-iodinated proteins of uninfected and Plasmodium falciparum-infected erythrocytes from natural infections of human patients. Cryopreserved infected blood from Gambian children with falciparum malaria was thawed, cultured to the middle trophozoite stage, and surface radio-iodinated. Trophozoite-infected cells were enriched about 10-fold on a Percoll gradient newly designed to separate cells based on their differential permeability to sorbitol. Infected blood was radio-iodinated and erythrocyes from the fraction enriched in parasitized cells and uninfected erythrocytes from the same sample obtained from the gradient and compared by SDS–PAGE and autoradiography. In each sample, parasitized erythrocytes contained one or more polypeptides of very high molecular weight (Mr 250000–300000) that were not found on uninfected erythrocytes from the same patient. These proteins were isolate-specific in size and number, suggesting that natural isolates contain a variable number of different P. falciparum phenotypes for this surface protein. In addition, these radio-iodinated surface proteins could not be extracted from the host cell membrane by the non-ionic detergent Triton X-100, but were extracted by SDS. The properties of these proteins suggest they are the equivalent for natural infections of the strain-dependent antigen previously described (Leech, Barnwell, Miller & Howard, 1984) on the surface of P. falciparum-infected Aotus erythrocytes. In addition, we observed a second parasite-dependent modification of labelled proteins on infected erythrocytes with the appearance of a new band of Mr 30000. There were also variations in the pattern of radio-isotope labelled proteins on uninfected erythrocytes from different patients.
Sialoglycoproteins and sialic acids ofPlasmodium knowlesischizont-infected erythrocytes and normal rhesus monkey erythrocytes
Authors: Howard R. J. , Reuter G. , Barnwell J. W. , Schauer R. 
Published: June 2009

SUMMARYThe effects of malaria infection on RBC sialic acids and sialoglycoproteins were studied with asexual blood-stage infections ofPlasmodium knowlesiin rhesus monkeys. Glycoprotein radio-isotope labelling methods were used to compare the sialoglycoproteins of normal RBC andP. knowlesischizont-infected RBC (SI-RBC). Tritiation of glycoproteins from SI-RBC with the standard sialidase + galactose oxidase/NaB3H4method or standard periodate/NaB3H4method was significantly decreased when compared to normal RBC. However, tritium uptake into glycoproteins was normal when SI-RBC were treated with 5-fold higher concentrations of both enzymes in the first labelling method, or with a 5-fold increase in the molar ratio of periodate to sialic acid in the second method. The mobility of tritiated host cell glycoproteins on SDS–polyacrylamide gels was identical for SI-RBC and normal RBC. New bands, possibly glycoproteins, of 230, 160, 90, 52, and 30 kDa were detected after labelling SI-RBC by the modified periodate/NaB3H4method. Sialic acid analysis of normal rhesus monkey RBC (62μg/1010RBC) revealed that 46% of the total sialic acid wasN-glycolylneuraminic acid, 33% wasN-acetyl-9-O-acetylneuraminic acid, and the remainderN-acetylneuraminic acid. SI-RBC collected either directly from infected monkeys or afterin vitroculture of ring-infected RBC in horse serum, had increased total sialic acid (126 or 115μg/1010RBC, respectively). The sialic acid content of infected RBC must increase during parasite development since RBC infected with ring-stageP. knowlesihad the same content as normal RBC. There was no significant difference in the ratio of the three sialic acids of SI-RBC and normal RBC. In contrast, the uninfected RBC from infected blood of different monkeys showed marked variation in sialic acid composition and generally had a lower sialic acid content than normal RBC.