Articles de revues : « Protozoa »

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Ohene-Adjei, Samuel, Ronald M. Teather, Michael Ivan et Robert J. Forster. « Postinoculation Protozoan Establishment and Association Patterns of Methanogenic Archaea in the Ovine Rumen ». Applied and Environmental Microbiology 73, n^o 14 (18 mai 2007) : 4609–18. http://dx.doi.org/10.1128/aem.02687-06.

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ABSTRACT Association patterns between archaea and rumen protozoa were evaluated by analyzing archaeal 16S rRNA gene clone libraries from ovine rumen inoculated with different protozoa. Five protozoan inoculation treatments, fauna free (negative control), holotrich and cellulolytic protozoa, Isotricha and Dasytricha spp., Entodinium spp., and total fauna (type A) were tested. We used denaturing gradient gel electrophoresis, quantitative PCR, and phylogenetic analysis to evaluate the impact of the protozoan inoculants on the respective archaeal communities. Protozoan 18S ribosomal DNA clone libraries were also evaluated to monitor the protozoal population that was established by the inoculation. Phylogenetic analysis suggested that archaeal clones associated with the fauna-free, the Entodinium, and the type A inoculations clustered primarily with uncultured phylotypes. Polyplastron multivesiculatum was the predominant protozoan strain established by the holotrich and cellulolytic protozoan treatment, and this resulted predominantly in archaeal clones affiliated with uncultured and cultured methanogenic phylotypes (Methanosphaera stadtmanae, Methanobrevibacter ruminantium, and Methanobacterium bryantii). Furthermore, the Isotricha and Dasytricha inoculation treatment resulted primarily in archaeal clones affiliated with Methanobrevibacter smithii. This report provides the first assessment of the influence of protozoa on archaea within the rumen microbial community and provides evidence to suggest that different archaeal phylotypes associate with specific groups of protozoa. The observed patterns may be linked to the evolution of commensal and symbiotic relationships between archaea and protozoa in the ovine rumen environment. This report further underscores the prevalence and potential importance of a rather large group of uncultivated archaea in the ovine rumen, probably unrelated to known methanogens and undocumented in the bovine rumen.

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Ffoulkes, D., et R. A. Leng. « Dynamics of protozoa in the rumen of cattle ». British Journal of Nutrition 59, n^o 3 (mai 1988) : 429–36. http://dx.doi.org/10.1079/bjn19880051.

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1. The dynamics of protozoa were studied in two groups of rumen-fistulated cattle fed on a basal diet of molassesad lib., with oaten chaff given at 6 or 18 g/kg live weight. This diet resulted in different mixtures of protozoal species in the populations in the rumen.2. The rumen protozoa were studied by intrarumen injections of protozoa labelled in vitro with [14CH3]choline. An indication of protozoal death and fermentation of protozoal cell residues was obtained by measuring14C loss via the methane pool.3. After a single injection of labelled protozoa, the decline in the specific radioactivity (μCi/g nitrogen) of the protozoal pool in the rumen indicated that first-order kinetic processes applied. Conversely the specific radioactivity of protozoa, incubated in rumen fluid, remained constant indicating no growth in vitro, presumably owing to a rapid exhaustion of essential nutrients.4. The protozoal populations in the rumen of cattle fed on the diet with the low level of oaten chaff were mainly small ciliates; but on the higher level of chaff in the diet, the large ciliates were a higher proportion of the total protozoal population present.5. The mean pool size of protozoa in the rumen was significantly larger and the protozoal half-life tended to be longer for cattle fed on the higher level of chaff in the diet. The apparent production rate of protozoa in cattle fed on each diet was not significantly different and there were no differences in the production rate of methane. The percentage losses of label from protozoa in the rumen via the methane pool were not significantly different on the two diets and indicated that 74% of the protozoa that were apparently irreversibly lost from the rumen could be accounted for by death and lysis in the rumen and therefore only 26% of protozoa apparently entered the lower digestive tract.

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Murphy, Brian G., Daniel Bradway, Timothy Walsh, George E. Sanders et Kevin Snekvik. « Gastric Cryptosporidiosis in Freshwater Angelfish (Pterophyllum Scalare) ». Journal of Veterinary Diagnostic Investigation 21, n^o 5 (septembre 2009) : 722–27. http://dx.doi.org/10.1177/104063870902100523.

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A freshwater angelfish ( Pterophyllum scalare) hatchery experienced variable levels of emaciation, poor growth rates, swollen coelomic cavities, anorexia, listlessness, and increased mortality within their fish. Multiple chemotherapeutic trials had been attempted without success. In affected fish, large numbers of protozoa were identified both histologically and ultrastructurally associated with the gastric mucosa. The youngest cohort of parasitized fish was the most severely affected and demonstrated the greatest morbidity and mortality. The protozoa were morphologically most consistent with Cryptosporidium. All of the protozoan life stages were identified ultrastructurally and protozoal genomic DNA was isolated from parasitized tissue viscera and sequenced. Histological, ultrastructural, genetic, and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium.

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Bird, Simon H., R. S. Hegarty et R. Woodgate. « Modes of transmission of rumen protozoa between mature sheep ». Animal Production Science 50, n^o 6 (2010) : 414. http://dx.doi.org/10.1071/an09216.

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Three experiments were conducted to evaluate routes by which viable rumen ciliate-protozoa may be transferred between mature sheep. Feed, water and faecal material were tested as possible vectors for protozoal transfer in addition to direct animal to animal contact. In Experiment 1, protozoa-free sheep were either offered or orally dosed with protozoa-contaminated material or allowed contact with faunated animals. The treated sheep were then monitored over a 4-week period for the appearance of protozoa in the rumen. Protozoa were successfully transferred to protozoa-free animals via contaminated water but no transfer occurred via feed or faeces or by direct animal to animal contact. In Experiment 2, the drinking water of penned faunated sheep was found to become contaminated with protozoa within 4–6 h of being placed in the pen. In Experiment 3, nine protozoa-free sheep were grazed in a paddock with a flock of 75 faunated ewes for periods of 1–3 weeks, and protozoa became established in one protozoa-free sheep. The results of these studies suggest that the most likely mode of transfer of protozoal cells from one sheep to another is via water, rather than by rumen fluid contaminating feed, or from faeces of faunated sheep. Further tests are required to demonstrate protozoal transmission via water occur under a range of conditions and inoculum levels.

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Bardi, Edoardo, Emilio Noviello et Lada Hofmannová. « Protozoa and protozoal infections in chelonians ». Journal of Exotic Pet Medicine 31 (octobre 2019) : 5–12. http://dx.doi.org/10.1053/j.jepm.2019.06.006.

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Rychert, Krzysztof, et Thomas Neu. « Protozoan impact on bacterial biofilm formation ». Biological Letters 47, n^o 1 (1 janvier 2010) : 3–10. http://dx.doi.org/10.2478/v10120-009-0017-x.

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Protozoan impact on bacterial biofilm formationConfocal laser scanning microscopy in combination with digital image analysis was used to assess the impact of protozoa on bacterial colonisation of surfaces. Bacterial biofilms were developed from activated sludge in microscope flow cells and were exposed to the grazing pressure of protozoa. The protozoan community from healthy activated sludge and a culture of flagellateBodo saltanswere used as grazers. Experiments comprised 48-h incubations in 3 treatment variants: bacteria with protozoa, bacteria with protozoa added after some time and bacteria without protozoa. When necessary, the elimination of protozoa from the inoculum was carried out with cycloheximide and NiSO4. Experiments demonstrated that protozoa from healthy activated sludge initially disturbed the biofilm development but later they could stimulate its growth. Similar results could be established in the experiment withBodo saltans(inoculum: 1000 cells/ml), however differences were not statistically significant. The finding that protozoa support biofilm development during specific stages may be relevant for biofilm studies with mixed environmental biofilm communities.

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Huws, S. A., M. R. F. Lee, A. H. Kingston-Smith, E. J. Kim, M. B. Scott, J. K. S. Tweed et N. D. Scollan. « Ruminal protozoal contribution to the duodenal flow of fatty acids following feeding of steers on forages differing in chloroplast content ». British Journal of Nutrition 108, n^o 12 (1 mars 2012) : 2207–14. http://dx.doi.org/10.1017/s0007114512000335.

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Ruminant products are criticised for their SFA content relative to PUFA, although n-6:n-3 PUFA is desirable for human health ( < 4). Rumen protozoa are rich in unsaturated fatty acids due to engulfment of PUFA-rich chloroplasts. Increasing the chloroplast content of rumen protozoa offers a potentially novel approach to enhance PUFA flow to the duodenum and subsequent incorporation into meat and milk. We evaluated protozoal contribution to duodenal n-3 PUFA flow due to intracellular chloroplast content. A total of six Holstein × Friesian steers were fed, in a two-period changeover design, either straw:concentrate (S:C, 60:40; DM basis; S:C, low chloroplast) or fresh perennial ryegrass (PRG; high chloroplast). Following 12 d adaptation to diet, ruminal protozoal and whole duodenal samples were obtained. N and fatty acid content of whole duodenum and rumen protozoal samples were assessed and protozoal 18S rDNA quantitative PCR performed, enabling calculation of protozoal N flow. The ratio of individual fatty acids:N in rumen protozoal samples was calculated to obtain protozoal fatty acid flows. Based on total fatty acid flow, contribution (%) of protozoa to individual fatty acid flows was calculated. Protozoal fatty acid data and microscopical observations revealed that protozoa were enriched with 18 : 3n-3 following PRG feeding, compared with the S:C diet, due to increased intracellular chloroplast content. However, duodenal protozoal 18S rDNA concentration post PRG feeding was low, indicating rumen retention of the protozoa. Nutrition influences the 18 : 3n-3 content of protozoa; the challenge is to increase protozoal flow to the small intestine, while maintaining sustainable rumen densities.

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Ndiaye, Mouhamadou, Khadim Diongue, Mame Cheikh Seck, Mamadou Alpha Diallo, Ekoué Kouevidjin, Aida Sadikh Badiane et Daouda Ndiaye. « Retrospective Assessment of The Intestinal Protozoan Distribution in Patients Admitted to The Hospital Aristide Le Dantec in Dakar, Senegal, from 2011 to 2020 ». Parasitologia 3, n^o 1 (23 décembre 2022) : 1–12. http://dx.doi.org/10.3390/parasitologia3010001.

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Infectious parasites, especially the intestinal protozoan parasites, continue to be a major public health problem in Africa, where many of the same factors contribute to the transmission of these parasites. This study was conducted to investigate the parasites causing intestinal protozoal infections diagnosed in Aristide Le Dantec hospital (Senegal). Direct examination and the Ritchie technique were used. Among the 3407 stool samples studied, 645 demonstrated the presence of intestinal protozoa in single parasitism, biparasitism, or polyparasitism, representing a prevalence of 18.93%. Out of a total of 645 protozoa, 579 (16.99%) were identified in monoparasitism in the following order: Entamoeba coli (6.87%) and Blastocystis hominis (5.69%) for low pathogenic species, and Entamoeba histolytica/dispar (2.31%) and Giardia intestinalis (1.32%) for pathogenic species. The rates of biparasitism and polyparasitism were 1.88% and 0.06%, respectively. The highest rate of parasites was 24.83% between the ages of 0–15 years. A logistical regression model indicated that intestinal protozoan infections were not associated with age groups. There was an association between age groups and Giardia intestinalis and Blastocystis hominis (p < 0.05). These results demonstrated the frequency of intestinal protozoa in Senegal. There is a need to implement treatment, prevention, and control measures to limit the circulation of these protozoan infections.

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Brinch, Ulla C., Flemming Ekelund et Carsten S. Jacobsen. « Method for Spiking Soil Samples with Organic Compounds ». Applied and Environmental Microbiology 68, n^o 4 (avril 2002) : 1808–16. http://dx.doi.org/10.1128/aem.68.4.1808-1816.2002.

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ABSTRACT We examined the harmful side effects on indigenous soil microorganisms of two organic solvents, acetone and dichloromethane, that are normally used for spiking of soil with polycyclic aromatic hydrocarbons for experimental purposes. The solvents were applied in two contamination protocols to either the whole soil sample or 25% of the soil volume, which was subsequently mixed with 75% untreated soil. For dichloromethane, we included a third protocol, which involved application to 80% of the soil volume with or without phenanthrene and introduction of Pseudomonas fluorescens VKI171 SJ132 genetically tagged with luxAB::Tn5. For both solvents, application to the whole sample resulted in severe side effects on both indigenous protozoa and bacteria. Application of dichloromethane to the whole soil volume immediately reduced the number of protozoa to below the detection limit. In one of the soils, the protozoan population was able to recover to the initial level within 2 weeks, in terms of numbers of protozoa; protozoan diversity, however, remained low. In soil spiked with dichloromethane with or without phenanthrene, the introduced P. fluorescens VKI171 SJ132 was able to grow to a density 1,000-fold higher than in control soil, probably due mainly to release of predation from indigenous protozoa. In order to minimize solvent effects on indigenous soil microorganisms when spiking native soil samples with compounds having a low water solubility, we propose a common protocol in which the contaminant dissolved in acetone is added to 25% of the soil sample, followed by evaporation of the solvent and mixing with the remaining 75% of the soil sample.

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Hastutiek, Poedji, Wiwik Misaco Yuniarti, Mufasirin Djaeri, Nunuk Dyah Retno Lastuti, Endang Suprihati et Lucia Tri Suwanti. « Prevalence and diversity of gastrointestinal protozoa in Madura cattle at Bangkalan Regency, East Java, Indonesia ». Veterinary World 12, n^o 2 (février 2019) : 198–204. http://dx.doi.org/10.14202/vetworld.2019.198-204.

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Aim: This study aimed to describe the gastrointestinal protozoa in Madura cattle at Bangkalan Regency, East Java, Indonesia. Materials and Methods: A total of 500 samples of Madura cattle feces were collected from 10 districts at Bangkalan Regency. Those ten districts represent the lowland and upland areas, and each district was represented by one village. The collected feces were examined using native, sedimentation, and floating methods. The species identification was determined by their morphology. Results: There were 357 (71.4%) samples positively infected with protozoan. The highest rate of sample with protozoan infection was at Kamal District (88.23%), and Bangkalan District (52.83%) was the lowest one. There were six species of protozoa that infected gastrointestinal tract; those are Eimeria spp., Balantidium spp., Isospora spp., Blastocystis spp., Entamoeba spp., and Cryptosporidium spp. The highest number of protozoa found in this research was Eimeria (53.42%) followed by Blastocystis (14.43%). In this study, we found that 295 samples (58.76%) infected by one kind of protozoa, 53 samples (10.56%) infected by two kinds of protozoa, and 11 samples (2.19%) infected by three kinds of protozoa. In addition, there were 65.54% of bulls infected with protozoa, considerably lower than cows (72.97%). Cattle aged 6 months-2 years old (73.39%) and >2 years old (71.25%) are known more prone to protozoan infections than cattle aged <6 months (66.15%). Conclusion: The present study revealed that protozoan infection of cattle is common in Bangkalan Regency. Studies focused on determining that the prevalence of protozoan, risk factors for the parasitism, and the geographic distribution are needed and will be effective guide for prevention and control measures.

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Pagati, Amara Lintang, Lucia Tri Suwanti, Chairul Anwar Nidom, Wiwik Misaco Yuniarti, Sarmanu Sarmanu et Endang Suprihati. « Prevalance of Gastrointestinal Protozoa of Cats in Animal Hospital and Animal Clinic in Surabaya ». Journal of Parasite Science 2, n^o 2 (3 décembre 2019) : 61. http://dx.doi.org/10.20473/jops.v2i2.16401.

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Research of gastrointestinal protozoan in cats at Surabaya are still limited. Protozoa infection of the gastrointestinal tract can cause diarrhea and even zoonosis. This research aimed to identify and determine the prevalence of protozoan in cats in animal hostptal and animal clinic in Surabaya. Ninety fecal samples were collected from 2 animal clinic and one animal hospital. Samples were examined e wet mount (native, sedimentation, and floatation) and (Ziehl Nellsen) stain. Protozoa was identified by using a light microscope with 400x and 1000x magnification. The result showed 68,89% of samples were positively infected by gastrointestinal protozoa. The protozoa were Blastocystis sp, Cryptosporidium sp, Giardia sp, and Eimeria sp. By chi square test, there was not significant differences the prevalence of gastrointestinal protozoan in cat between sex, age, breed, and diarrhea status

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Dijkstra, Jan, et Seerp Tamminga. « Simulation of the effects of diet on the contribution of rumen protozoa to degradation of fibre in the rumen ». British Journal of Nutrition 74, n^o 5 (novembre 1995) : 617–34. http://dx.doi.org/10.1079/bjn19950166.

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A previously described mathematical model, that simulates the metabolic activities of rumen bacteria and protozoa, was used to examine the contribution of protozoa to neutral-detergent fibre (NDF) degradation in the rumen of cattle. Comparisons between predicted and experimentally observed NDF degradation showed general agreement. Further simulations were performed with diets containing variable proportions of concentrate (between 0 and 1 kg/kg diet DM) and at intake levels ranging between 5·3 and 21·0 kg DM/d. The simulated protozoal contribution to NDF degradation was 17–21% at the lowest intake level. Except for the all-concentrate diets, raising the feed intake level reduced this contribution to 5–3% at the highest intake level. The changes in contribution of protozoa to NDF degradation were related to variations in the fibrolytic bacteria: protozoa value and the NDF-degrading activities of protozoa predicted by the model. In simulations where dietary NDF levels were reduced and starch and sugar levels were increased independently, protozoal contribution to NDF degradation generally increased. These differences were reflected also in the generally increased protozoal contribution to NDF degradation predicted in response to a decreased roughage:concentrate value. The contribution of protozoa also generally declined in response to added N. These changes in predicted protozoal contribution to NDF degradation resulting from dietary variations provided possible explanations for the differences in rumen NDF degradation observed when animals are defaunated.

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Williams, Alan G., et Susan E. Withers. « Changes in the rumen microbial population and its activities during the refaunation period after the reintroduction of ciliate protozoa into the rumen of defaunated sheep ». Canadian Journal of Microbiology 39, n^o 1 (1 janvier 1993) : 61–69. http://dx.doi.org/10.1139/m93-009.

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Changes in the microbial populations, their activities, and the ruminal fermentation were monitored for 50 d following the reintroduction of ciliate protozoa into four defaunated sheep. A protozoal population was reestablished successfully in each recipient, using a washed inoculum containing approximately 103 cells, although there were between-animal differences in the rates of recolonization and genus establishment. Entodinium spp. predominated in the initial stages of the refaunation period and had an apparent maximal generation time of 9–10 h. Bacterial and fungal numbers did not decline following the reintroduction of protozoa and a small transient increase in the numbers of amylolytic and xylanolytic bacteria and fungal zoospores occurred in the early stages of refaunation when the protozoal population was < 105/g ruminal contents, but these subsequently declined as the protozoa established. Although the fibrolytic bacterial population was lowest in period 3 (> 105 protozoa/g), the in sacco ruminal digestion of Lolium perenne hay and polysaccharolytic enzyme activities in the solids-associated populations were either maintained or increased when protozoa were present confirming the important contribution of protozoa to fibre breakdown in the rumen. Significant changes in ruminal microbial activities occurred after protozoal reinoculation but before the rumen had refaunated completely. Arylamidase activities in the liquor-phase population and ruminal ammonia concentrations increased significantly within 48 h of transfaunation; the magnitude of the effects became more pronounced as the protozoal population developed. However, volatile fatty acid formation and ruminal pH were not affected after the reintroduction of protozoa.Key words: rumen, sheep, ciliate protozoa.

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Yáñez-Ruiz, David R., Nigel D. Scollan, Roger J. Merry et Charles J. Newbold. « Contribution of rumen protozoa to duodenal flow of nitrogen, conjugated linoleic acid and vaccenic acid in steers fed silages differing in their water-soluble carbohydrate content ». British Journal of Nutrition 96, n^o 5 (novembre 2006) : 861–69. http://dx.doi.org/10.1017/bjn20061927.

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The present experiment was designed to estimate the quantitative contribution of rumen protozoa to the total N, conjugated linoleic acid (CLA) and vaccenic acid (VA;trans-11–18:1) flow to the duodenum of steers fed two silage diets: control silage (CS) and silage high in water-soluble carbohydrates (HS). Protozoal duodenal flows were estimated using a real-time PCR assay to quantify the genes encoding protozoal 18S ribosomal RNA. Denaturing gradient gel electrophoresis was used to confirm that the rumen protozoa populations were similar to the protozoal population flowing to the duodenum. Estimated duodenal flow of protozoal N was 14·2 and 18·2 g/d (P>0·05) for animals fed the CS and HS diets respectively. Protozoal flow thus represented between 12 and 15 % of the total N duodenal flow. In terms of fatty acid flow, protozoa accounted for between 30 and 43 % of the CLA and 40 % of the VA reaching the duodenum. The contribution of protozoa to 16:0 and 18:0 flows to the duodenum was less than 20 and 10 %, respectively. These results show that the fatty acids within protozoa make up a significant proportion of the CLA and VA reaching the duodenum of ruminants.

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Nurhayati, Nurhayati. « GAMBARAN INFEKSI PROTOZOA INTESTINAL PADA ANAK BINAAN RUMAH SINGGAH AMANAH KOTA PADANG ». Majalah Kedokteran Andalas 34, n^o 1 (2 mai 2015) : 60. http://dx.doi.org/10.22338/mka.v34.i1.p60-69.2010.

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AbstrakInfeksi protozoa intestinal masih merupakan masalah kesehatan masyarakat di negara tropis dan negara berkembang. Yang termasuk ke dalam protozoa intestinal patogen di antaranya adalah G. lamblia dan E. histolitika.Telah dilakukan penelitian terhadap anak binaan Rumah Singgah “Amanah”, Kelurahan Rimbo Kaluang, Kecamatan Padang Barat, Kota Padang. Pemeriksaan tinja dilakukan terhadap 66 anak dengan metode langsung menggunakan eosin dan lugol. Tujuan penelitian ini adalah untuk mengetahui gambaran infeksi protozoa intestinal pada anak binaan rumah singgah Amanah.Telah dilakukan penelitian di Rumah Singgah “Amanah”, Kelurahan Rimbo Kaluang, Kecamatan Padang Barat, Kota Padang, terhadap anak biaHasil penelitian ini menunjukkan bahwa anak-anak yang terinfeksi protozoa intestinal sebesar 40,91%. Berdasarkan jenis spesies, distribusi frekuensi terbanyak yang menginfeksi anak adalah G. lamblia yaitu 37,88%, sedangkan infeksi oleh E. histolitika adalah 3,03%. Frekuensi infeksi G. Lamblia lebih tinggi pada umur < 10 tahun yaitu 27,27%, tetapi pada infeksi E. histolitika terlihat tidak ada perbedaan. Distribusi infeksi berdasarkan jenis kelamin hampir sama pada G. lamblia maupun E. histolitika. Berdasarkan pekerjaan, lebih separuh anak binaan yang terinfeksi protozoa intestinal bekerja sebagai penjaja makanan.Kata kunci: Protozoa intestinal, G. lamblia, E. histolitikaAbstractPrevalence of intestinal protozoan infection in Rumah Singgah Amanah, Kota Padang. Intestinal protozoan infection is still a public health problem in tropical countries and developing countries. The intestinal protozoan pathogen of which is G. lamblia and E.histolitika.This research is descriptif study and it was conducted in Rumah Singgah Amanah, Kelurahan Rimbo Kaluang, Kecamatan Padang Barat, Kota Padang. Stool examination has been carried out to 66 children by direct fecal examination method using eosin and Lugol. The purpose of this research is to know the description of intestinal protozoan in fection in Rumah Singgah Amanah.Prevalence of intestinal protozoa infection was 40,91%, the highest frequent infection was G. lamblia which was 37.88%, E. histolitika was 3.03%. FrequencyARTIKEL PENELITIAN61of G. lamblia infection was higher in age <10 years is 27.27%. There was no different in age in E.histolytica infection. There was no different in sex in both infection. Half of children with intestinal protozoa infection were food seller.Key words : Intestinal Protozoa, G. lamblia, E. histolitika

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Adeiza, A. M., N. A. Sani, N. B. Alhaji, E. A. Godwin, C. E. Okwolo et G. Uchendu. « Prevalence and Diversity of Zoonotic Protozoa in Dogs in Lokoja, North ‎Central, Nigeria ». Sahel Journal of Veterinary Sciences 20, n^o 4 (31 décembre 2023) : 34–40. http://dx.doi.org/10.54058/saheljvs.v20i4.392.

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The risk of zoonotic protozoan diseases has increased in recent times through the unregulated breeding of dogs in the neighbourhood of human dwellings. Dogs (341) brought into the seven major (Based on full employment of at least one veterinarian) veterinary clinics in Lokoja, North Central Nigeria (October 2021 to August, 2022) for medical evaluations were enlisted in this study to determine the prevalence and diversity of zoonotic protozoa in the dogs. Faecal and blood samples were screened using modified Ziehl – Neelsen and direct microscopy techniques for the presence of intestinal and blood protozoan oocysts. Out of the faecal and blood samples collected from each of the 341 dogs enlisted in the study, 207 (60.7%) were positive for protozoa. Faecal protozoa had a higher frequency of occurrence; 50.4% (172/341) compared to blood protozoan; 10.3% (35/341).Eimeria histolytica was the most frequently occurring protozoa; 14.4% (49/341), followed by Giardia; 12.0% (41/341) and the least was Babesia; 3.8% (13/341). There was however no significant difference in the prevalence of protozoa and the type of parasite (P = 0.702). Age-specific, prevalence showed that puppies under 1 year had a higher prevalence of protozoa; 84.1% (174/207) compared to the adults; 16.0% (33/207). The relationship was not significant (χ2=3.816; P = 0.702). Local breed of dogs had the highest prevalence of protozoa; 68.2% (137/201), followed by exotic; 60.47% (26/43) and the least was the cross breed, 45.4% (44/97). There is a significant difference in the prevalence of protozoa in local and cross breeds of dogs (P = 0.001). The female dogs had a higher prevalence; 77.0% (117/152) compared to males; 45.5% (86/189). There was an association between prevalence of protozoa and sex of dogs (χ2 = 16.77; P = 0.010).

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Lian, Liyin, Qian Sun, Xinyi Huang, Wanjing Li, Yanjun Cui, Yuebo Pan, Xianyu Yang et Pu Wang. « Inhibition of Cell Apoptosis by Apicomplexan Protozoa–Host Interaction in the Early Stage of Infection ». Animals 13, n^o 24 (11 décembre 2023) : 3817. http://dx.doi.org/10.3390/ani13243817.

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Apicomplexan protozoa, which are a group of specialized intracellular parasitic protozoa, infect humans and other animals and cause a variety of diseases. The lack of research on the interaction mechanism between Apicomplexan protozoa and their hosts is a key factor restricting the development of new drugs and vaccines. In the early stages of infection, cell apoptosis is inhibited by Apicomplexan protozoa through their interaction with the host cells; thereby, the survival and reproduction of Apicomplexan protozoa in host cells is promoted. In this review, the key virulence proteins and pathways are introduced regarding the inhibition of cell apoptosis by the interaction between the protozoa and their host during the early stage of Apicomplexan protozoa infection. It provides a theoretical basis for the development of drugs or vaccines for protozoal diseases.

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Williams, Yvette J., Suzanne M. Rea, Sam Popovski, Carolyn L. Pimm, Andrew J. Williams, Andrew F. Toovey, Lucy C. Skillman et André-Denis G. Wright. « Reponses of sheep to a vaccination of entodinial or mixed rumen protozoal antigens to reduce rumen protozoal numbers ». British Journal of Nutrition 99, n^o 1 (15 août 2007) : 100–109. http://dx.doi.org/10.1017/s0007114507801553.

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Two rumen protozoa vaccine formulations containing either whole fixed Entodinium or mixed rumen protozoa cells were tested on Merino sheep with the aim of decreasing the number and/or activity of protozoa in the rumen. Negative control (no antigen) and positive control (Tetrahymena corlissi antigens) treatments were also included in the experiment. Blood and saliva were sampled to measure the specific immune response. Protozoal numbers in the rumen were monitored by microscopic counts. Vaccination with protozoal formulations resulted in the presence of specific IgG in plasma and saliva, but saliva titres were low. Titres after secondary vaccination were higher (P < 0·05) than after primary vaccination. There was a moderate (r2 0·556) relationship (P < 0·05) between plasma and saliva titres for the rumen protozoal vaccine formulations. Rumen protozoa were not decreased (P>0·05) by the vaccination and there was also no difference (P>0·05) between treatments in rumen fluid ammonia-N concentration or wool growth. In vitro studies investigated the binding ability of the antibodies and estimated the amount of antibody required to reduce cell numbers in the rumen. The studies showed that the antibodies did bind to and reduced protozoa numbers, but the amount of antibody generated by vaccination was not enough to produce results in an in vivo system. It is suggested that the vaccine could be improved if specific protozoal antigens are determined and isolated and that improved understanding of the actions of protozoa antibodies in rumen fluid and the relationships between levels of antibodies and numbers of protozoa in the rumen is needed.

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Michalowski, T., J. Harmeyer et G. Breves. « The passage of protozoa from the reticulo-rumen through the omasum of sheep ». British Journal of Nutrition 56, n^o 3 (novembre 1986) : 625–34. http://dx.doi.org/10.1079/bjn19860143.

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1. Protozoa in rumen contents and omasal effluent of growing wethers were counted. The wethers were equipped with rumen and abomasal cannulas, and omasal sleeves attached to the omasal-abomasal orifice. Rumen fluid dilution rates were elevated by continuous infusions of hypertonic mineral solutions (34 litres/d) for 24 d. Rumen contents and omasal effluent were sampled between 9 and 21 h during the last 10 d of each experiment.2. Protozoa1 concentrations in omasal effluent were only 0.24.3 those found in the rumen under normal conditions. The ratio of protozoal concentrations in rumen: those in omasal effluent was for small Diplodinium spp. 4.6 (SD 0.9), forOphryoscolexspp. 4.3 (SD 1.0), forDasytricha ruminantium4.0 (SD 0.5), forIsotrichaspp. 3.8 (SD 0.8), forEntodiniumspp. 3.6 (SD 0.9) and forPolyplastron multivesiculatum2.6 (SD 0.5).3. Elevation of rumen fluid dilution rate by 20 and 55% respectively, increased protozoal concentrations in omasal effluents from 22 to 33% and from 31 to 47% those in rumen contents. The apparent residence times of protozoa in the rumen were decreased 50% by the infusion of a mineral-salt solution. The increase in rumen fluid dilution rate had no significant effect on concentrations of protozoa in the rumen or on the differences of the apparent residence times between different species. The apparent residence time of holotrichs remained the same before and after infusion of the mineral-salt solution.4. Apparent residence times of individual species of protozoa in the rumen were, under normal feeding conditions, 2.55 d, and were four to six times longer than the mean residence time of CrEDTA in the rumen.

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Neill, L., M. de S. Dayrell, J. K. G. Kramer et M. Ivan. « Procedure for analysis of phosphatidylcholine as a protozoal marker in ruminants ». Canadian Journal of Animal Science 72, n^o 3 (1 septembre 1992) : 717–19. http://dx.doi.org/10.4141/cjas92-084.

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A procedure was developed to analyze phosphatidylcholine in ruminal protozoa and duodenal digesta, for the estimation of the flow of protozoal constituents from the stomach to the small intestine of ruminant animals. The procedure requires 15–20 mg of dry ruminal protozoa and 50–60 mg of dry duodenal digesta. Key words: Phosphatidylcholine, protozoa, duodenal flow, ruminants

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Li, Ellen, et Samuel L. Stanley. « PROTOZOA ». Gastroenterology Clinics of North America 25, n^o 3 (septembre 1996) : 471–92. http://dx.doi.org/10.1016/s0889-8553(05)70259-4.

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Gorham, Ella Martinsen. « Protozoa ». New England Review 39, n^o 4 (2018) : 25–37. http://dx.doi.org/10.1353/ner.2018.0102.

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Zhao, Hongzhou, Arrvindh Shriraman, Snehasish Kumar et Sandhya Dwarkadas. « Protozoa ». ACM SIGARCH Computer Architecture News 41, n^o 3 (26 juin 2013) : 547–58. http://dx.doi.org/10.1145/2508148.2485969.

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Hamdani, Aldi, Nunuk Dyah Retno Lastuti, Yeni Dhamayanti, Setiawan Koesdarto, Agus Sunarso et Poedji Hastutiek. « Prevalence of Gastrointestinal Protozoa on Bali Cattle in Lopok Sub-District, Sumbawa District ». Journal of Parasite Science 5, n^o 2 (30 septembre 2021) : 55. http://dx.doi.org/10.20473/jops.v5i2.30373.

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This study aims to determine the prevalence of gastrointestinal protozoa on Bali cattle in Lopok Sub-District, Sumbawa District. The study was conducted from January to April 2021 by taking 100 samples of Bali cattle feces from 7 villages in Lopok Sub-District, Sumbawa District. Samples were examined by sedimentation and floating methods. Species identification was determined by the morphology of the protozoa. A total of 62 (62%) samples were positively infected with protozoa. There were 4 species of gastrointestinal protozoa found infecting Bali cattle, namely Eimeria sp., Blastocytis sp., Entamoeba sp., and Balantidium sp. Most of the protozoa found in this study were Eimeria sp. (54%) and Blastocytis sp. (5%). This study found 59 samples (59%) were infected by one type of protozoa, 3 samples (3%) were infected by two types of protozoa. Cattle aged 0-6 months (81%) had a higher prevalence rate and were more susceptible to protozoal infections than cows aged 7 months – 2 years (70.3%) and more than 2 years (45.2%).

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Kilimcioglu, Ali Ahmet, Yavuz Havlucu, Nogay Girginkardesler, Pınar Çelik, Kor Yereli et Ahmet Özbilgin. « Putative Bronchopulmonary Flagellated Protozoa in Immunosuppressed Patients ». BioMed Research International 2014 (2014) : 1–5. http://dx.doi.org/10.1155/2014/912346.

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Flagellated protozoa that cause bronchopulmonary symptoms in humans are commonly neglected. These protozoal forms which were presumed to be “flagellated protozoa” have been previously identified in immunosuppressed patients in a number of studies, but have not been certainly classified so far. Since no human cases of bronchopulmonary flagellated protozoa were reported from Turkey, we aimed to investigate these putative protozoa in immunosuppressed patients who are particularly at risk of infectious diseases. Bronchoalveolar lavage fluid samples of 110 immunosuppressed adult patients who were admitted to the Department of Chest Diseases, Hafsa Sultan Hospital of Celal Bayar University, Manisa, Turkey, were examined in terms of parasites by light microscopy. Flagellated protozoal forms were detected in nine (8.2%) of 110 cases. Metronidazole (500 mgb.i.d.for 30 days) was given to all positive cases and a second bronchoscopy was performed at the end of the treatment, which revealed no parasites. In conclusion, immunosuppressed patients with bronchopulmonary symptoms should attentively be examined with regard to flagellated protozoa which can easily be misidentified as epithelial cells.

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Muthee, Antony, Mary Gitahi, Rael Musili et Martin Mutuku. « Prevalence and Distribution of Geo-Helminths and Intestinal Protozoa Infections among School-Going Children in Nyeri County, Kenya ». African Journal of Empirical Research 5, n^o 2 (18 juin 2024) : 787–99. http://dx.doi.org/10.51867/ajernet.5.2.69.

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The goal of this study was to determine how common and widespread geo-helminths, STH, and intestinal protozoa infections are in the Mathira constituency of Nyeri County, Kenya. The study aimed to determine the prevalence of geohelminths and intestinal protozoa, as well as the distribution of STH and intestinal protozoa infections in school-going children. Cochran formulae guided the design of a cross-sectional study on a population of 174 children, yielding complete data for 164 of them. The social determinants of the health model guided this study. A structured questionnaire was applied to data collection to establish the demographic characteristics of the study participants in the identified three primary schools in the study site. They were examined for STH and protozoa infections by the quantitative Kato-Katz technique for STH and formal ether concentration techniques for intestinal protozoa infection. Statistical analysis was done using R Studio and the risk ratio. Findings showed that of the 56 samples examined in Kihuro primary school, 12 (21.4%) and 6 (10.7%) were positive for protozoan and STH infections. Similarly, 33% of the children in Gathuini primary school were found to be positive for protozoan infections, while 13% were infected with STH. In Gikumbo primary school, 20.4% of the children were infected with protozoan parasites, compared to 13% of STH infections. However, there was a variation in infection prevalence based on gender across the three selected sites. Children in Kihuro primary school were 0.12 times more at risk of STH infection compared to 0.3 times more at risk of protozoa infections. The intestinal protozoa infection was higher than that for the geohelminths infection in Gathuini primary school. Children in Gathuini primary school were 0.12 times more at risk of STH infection compared to 0.46 times more at risk of protozoa infections. Children in Gikumbo primary school were 0.1 times at risk of STH infection compared to 0.26 times at risk of protozoa infections, implying that they were more prone to protozoan infections than STH infections. The study concluded that the age and gender of students had no statistical significance. The study recommended that government institutions and non-governmental organizations should intervene and undertake adequate control measures against geo-helminth parasites by making sure there is access to safe water and improved sanitation in the area. Moreover, health education programs should be intensified in the area and beyond to raise awareness of geo-helminths and intestinal protozoa infection, means of transmission and control measures, and the improvement of hygiene practices for both children and parents.

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Denton, Bethany L., Leanne E. Diese, Jeffrey L. Firkins et Timothy J. Hackmann. « Accumulation of Reserve Carbohydrate by Rumen Protozoa and Bacteria in Competition for Glucose ». Applied and Environmental Microbiology 81, n^o 5 (29 décembre 2014) : 1832–38. http://dx.doi.org/10.1128/aem.03736-14.

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ABSTRACTThe aim of this study was to determine if rumen protozoa could form large amounts of reserve carbohydrate compared to the amounts formed by bacteria when competing for glucose in batch cultures. We separated large protozoa and small bacteria from rumen fluid by filtration and centrifugation, recombined equal protein masses of each group into one mixture, and subsequently harvested (reseparated) these groups at intervals after glucose dosing. This method allowed us to monitor reserve carbohydrate accumulation of protozoa and bacteria individually. When mixtures were dosed with a moderate concentration of glucose (4.62 or 5 mM) (n= 2 each), protozoa accumulated large amounts of reserve carbohydrate; 58.7% (standard error of the mean [SEM], 2.2%) glucose carbon was recovered from protozoal reserve carbohydrate at time of peak reserve carbohydrate concentrations. Only 1.7% (SEM, 2.2%) was recovered in bacterial reserve carbohydrate, which was less than that for protozoa (P< 0.001). When provided a high concentration of glucose (20 mM) (n= 4 each), 24.1% (SEM, 2.2%) of glucose carbon was recovered from protozoal reserve carbohydrate, which was still higher (P= 0.001) than the 5.0% (SEM, 2.2%) glucose carbon recovered from bacterial reserve carbohydrate. Our novel competition experiments directly demonstrate that mixed protozoa can sequester sugar away from bacteria by accumulating reserve carbohydrate, giving protozoa a competitive advantage and stabilizing fermentation in the rumen. Similar experiments could be used to investigate the importance of starch sequestration.

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Maryanti, Esy, M. Reyhan Ahza Hamidy et Lilly Haslinda. « Identifikasi Protozoa Usus Oportunistik dan Faktor Risikonya Pada Anak Panti Asuhan Kota Pekanbaru ». Jurnal Ilmu Kedokteran 13, n^o 2 (1 septembre 2019) : 55. http://dx.doi.org/10.26891/jik.v13i2.2019.55-62.

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Opportunistic intestinal protozoa are protozoa that can infect humans at a time when the body’s defense system isdeclining (immunocompromising). Opportunistic protozoan infections are infections by intestinal protozoa that werenot previously considered important, but now can cause disease in humans. Opportunistic intestinal protozoan infectionsbesides being found in immunocompromised patients are also reported to infect children. Some of the intestinalprotozoan species that have been identified to cause infection are Cryptosporidium sp, Isospora belii, Cyclospora sp,and Blastocystis hominis. This study was an analytical study with a cross sectional design conducted in June 2018until January 2019. In this study, modified Ziehl-Neelsen staining was used and the results were 25.6% of orphanagesinfected with opportunistic intestinal protozoa, which consisted of Cryptosporidium sp. as much as 14.1%, Blastocystishominis as much as 4.6%, infection with a mixture of Cryptosporidium sp and Blastocystis hominis as much as 4.6%,Isospora belii as much as 2.3%, and no infection by Cyclospora cayetanensis. There was no association betweenopportunistic intestinal protozoan infections with poor handwashing habits, bowel habits, food hygiene, drinkingwater treatment, and bad animal raising habits.

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Punia, B. S., J. Leibholz et G. J. Faichney. « Rate of production of protozoa in the rumen and the flow of protozoal nitrogen to the duodenum in sheep and cattle given a pelleted diet of lucerne hay and barley ». Journal of Agricultural Science 118, n^o 2 (avril 1992) : 229–36. http://dx.doi.org/10.1017/s0021859600068830.

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SUMMARYTwo crossbred wethers (c. 45 kg) and two Hereford heifers (c. 215 kg) were fitted with permanent cannulas in the rumen and abomasum and given a diet of lucerne hay and barley (60:40). Organic matter (OM) intakes were 0·67 kg/day for sheep and 3·14 kg/day for cattle.The mean numbers of protozoa in the rumen fluid were 9·3 × 105/ml for sheep and 7·4 × 105/ml for cattle. 14C-labelled protozoa were prepared by incubating rumen fluid in vitro with [14C]methyl choline and then isolating them by sedimentation and differential centrifugation. The labelled protozoa were returned to the rumen of each of the donor animals in a single injection. The specific radioactivity in mixed protozoa isolated from the rumen was measured for 3 days. The protozoal pool size was 10 and 12 g N in the sheep and 64 and 44 g N in the cattle. Protozoal N contributed, on average, 48% of the total N in the rumen.Production of protozoal N in the rumen was 9·5 and 11·2 g/day for the sheep and 49·5 and 38·6 g/day for the cattle. The flow of protozoal N from the abomasum was calculated to be 1·6 and 2·9 g/day for sheep and 17·3 and 13·3 g/day for cattle. Thus, on average, 79% of the protozoal N was recycled within the rumen of the sheep and 65% within the rumen of the cattle. Protozoal N made up 11–20% of total N flow from the abomasum. The turnover times of 14C-labelled protozoa injected into the rumen of the sheep and the cattle were similar (26·2 and 26·8 h for sheep; 30·8 and 27·5 h for cattle) and were similar to those for protozoa isolated from the rumen of sheep after direct intraruminal injection of [14C]methyl choline (28 and 36 h).

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Wang, Wei, Leslie M. Shor, Eugene J. LeBoeuf, John P. Wikswo et David S. Kosson. « Mobility of Protozoa through Narrow Channels ». Applied and Environmental Microbiology 71, n^o 8 (août 2005) : 4628–37. http://dx.doi.org/10.1128/aem.71.8.4628-4637.2005.

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ABSTRACT Microbes in the environment are profoundly affected by chemical and physical heterogeneities occurring on a spatial scale of millimeters to micrometers. Physical refuges are critical for maintaining stable bacterial populations in the presence of high predation pressure by protozoa. The effects of microscale heterogeneity, however, are difficult to replicate and observe using conventional experimental techniques. The objective of this research was to investigate the effect of spatial constraints on the mobility of six species of marine protozoa. Microfluidic devices were created with small channels similar in size to pore spaces in soil or sediment systems. Individuals from each species of protozoa tested were able to rapidly discover and move within these channels. The time required for locating the channel entrance from the source well increased with protozoan size and decreased with channel height. Protozoa of every species were able to pass constrictions with dimensions equal to or smaller than the individual's unconstrained cross-sectional area. Channel geometry was also an important factor affecting protozoan mobility. Linear rates of motion for various species of protozoa varied by channel size. In relatively wide channels, typical rates of motion were 300 to 500 μm s−1 (or about 1 m per hour). As the channel dimensions decreased, however, motilities slowed more than an order of magnitude to 20 μm s−1. Protozoa were consistently observed to exhibit several strategies for successfully traversing channel reductions. The empirical results and qualitative observations resulting from this research help define the physical limitations on protozoan grazing, a critical process affecting microbes in the environment.

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Sinclair, James L., et Martin Alexander. « Effect of protozoan predation on relative abundance of fast- and slow-growing bacteria ». Canadian Journal of Microbiology 35, n^o 5 (1 mai 1989) : 578–82. http://dx.doi.org/10.1139/m89-092.

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The survival of six bacterial species that had different growth rates was tested in raw sewage and sewage that was rendered free of protozoa. When test bacteria were added to protozoa-free sewage at densities of approximately 105 to 106 cells/mL, five of the six species did not decline below 105 cells/mL. If protozoa were present, the population sizes of all test species were markedly reduced, but bacterial species able to grow faster in artificial media had the larger number of survivors. When the same bacteria were inoculated into protozoa-free sewage at densities of less than 103 cells/mL, only the three species able to grow quickly in artificial media increased in abundance. When the six species were inoculated at the same densities into sewage containing protozoa, the three slow-growing species were rapidly eliminated, and two of the three fast-growing species survived in detectable numbers. We suggest that in environments with intense protozoan predation, protozoa may alter the composition of the bacterial community by eliminating slow-growing bacteria.Key words: growth rate, predation, protozoa, sewage.

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Dudlová, A., P. Juriš, P. Jarčuška, L. Čisláková, I. Papajová et V. Krčméry. « Epidemiological risks of endoparasitoses spread by municipal waste water ». Helminthologia 52, n^o 3 (1 septembre 2015) : 188–94. http://dx.doi.org/10.1515/helmin-2015-0032.

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AbstractThe occurrence of developmental stages of endoparasite germs (cysts, oocysts, protozoa, and helminth eggs) as an indirect detection factor of endoparasitoses circulation in the environment, was examined in raw municipal wastewater, sludge and biologically cleaned waste water. Examination of municipal wastewater and sludge from five monitored wastewater treatment plants (WWTPs) in east Slovakia, from various fractions of municipal wastewater, confirmed 35.87 % positivity of samples for the endoparasitic germs. Among of all analysed samples 11.09 % were protozoan oo(cysts) and 20.87 % were helminth eggs. 3.91 % of samples showed positivity to both the helminth eggs and protozoan oo(cysts). In the raw wastewater the protozoa comprised of Giardia spp. (1.08 %) and Entamoeba spp. (1.08 %). The helminth eggs primarily consisted of Ascaris spp. (4.35 %) and strongyle-type eggs (3.26 %). No germs of protozoa or helminths were found in the treated wastewater. However, the highest presence of the germs was found in drained stabilised sludge. The average number of oo(cysts)/kg was 2.86±0.24 and the average number of helminth eggs/kg was 5.77±0.09. In all kinds of sludge, obtained during the process of wastewater treatment, there were protozoan (Giardia spp., Cryptosporidium spp., Entamoeba spp.) and helminths eggs (Ascaris spp., Trichuris spp., Taenia spp., Hymenolepis spp., or strongyle-type eggs) presented. In drained (condensed) stabilised sludge the eggs of Capillaria spp. and Toxocara spp. were also detected. From the epidemiological aspect the sewage sludge, due to high concentration of protozoal oo(cysts) or helminth eggs, represents a significant epidemiological risk for the endoparasitoses dissemination.

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Baré, Julie, Kurt Houf, Tine Verstraete, Mario Vaerewijck et Koen Sabbe. « Persistence of Free-Living Protozoan Communities across Rearing Cycles in Commercial Poultry Houses ». Applied and Environmental Microbiology 77, n^o 5 (14 janvier 2011) : 1763–69. http://dx.doi.org/10.1128/aem.01756-10.

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ABSTRACTThe introduction and survival of zoonotic bacterial pathogens in poultry farming have been linked to bacterial association with free-living protozoa. To date, however, no information is available on the persistence of protozoan communities in these environments across consecutive rearing cycles and how it is affected by farm- and habitat-specific characteristics and management strategies. We therefore investigated the spatial and temporal dynamics of free-living protozoa in three habitats (pipeline, water, and miscellaneous samples) in three commercial poultry houses across three rearing cycles by using the molecular fingerprinting technique denaturing gradient gel electrophoresis (DGGE). Our study provides strong evidence for the long-term (ca. 6-month) persistence of protozoa in broiler houses across consecutive rearing cycles. Various free-living protozoa (flagellates, ciliates, and amoebae), including known vectors of bacterial pathogens, were observed during the down periods in between rearing cycles. In addition, multivariate analysis and variation partitioning showed that the protozoan community structure in the broiler houses showed almost no change across rearing cycles and remained highly habitat and farm specific. Unlike in natural environments, protozoan communities inside broiler houses are therefore not seasonal. Our results imply that currently used biosecurity measures (cleaning and disinfection) applied during the down periods are not effective against many protozoans and therefore cannot prevent potential cross-contamination of bacterial pathogens via free-living protozoa between rearing cycles.

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Maryanti, Esy, Suri Dwi Lesmana et Hendro Mandela. « Deteksi Protozoa Usus Oportunistik pada Penderita Diare Anak di Puskesmas Rawat Inap Pekanbaru ». Jurnal Ilmu Kedokteran 9, n^o 1 (29 décembre 2017) : 22. http://dx.doi.org/10.26891/jik.v9i1.2015.22-26.

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Diarrhea is still a public health problem, especially in developing countries. Diarrhea causes morbidity and highmortality in children. Diarrhea can be caused by viruses, bacteria, parasites and food poisoning. One of the parasitethat can cause diarrhea is intestinal protozoa. Lately, attention to intestinal opportunistic protozoan infections isincreasing. Opportunistic intestinal protozoa infection is an infection by intestinal protozoa that had not consideredimportant and now can cause disease in humans. Cryptosporidium sp, Cyclospora cayetanensis, Isospora belii andBlastocystis hominis are opportunistic intestinal protozoa. The clinical manifestations of the infection depends on theimmune status of patients, ranging from asymptomatic in immunocompetent individuals to chronic diarrhea not curedand fatal in patients imunokompromis. This study aims to detect opportunistic intestinal protozoa in children withdiarrhea patients in health centers Inpatient Pekanbaru used modified acid fast stain procedure. A total of 76 samplestested positive obtained 22.3% of opportunistic intestinal protozoa found that 9.2% were infected with Cryptosporidiumsp, Cyclospora infection were 2.6% and Blastocystis hominis 10.5%, while Isospora not found.

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Moreno, Ana Maria, Carsten Matz, Staffan Kjelleberg et Mike Manefield. « Identification of Ciliate Grazers of Autotrophic Bacteria in Ammonia-Oxidizing Activated Sludge by RNA Stable Isotope Probing ». Applied and Environmental Microbiology 76, n^o 7 (5 février 2010) : 2203–11. http://dx.doi.org/10.1128/aem.02777-09.

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ABSTRACT It is well understood that protozoa play a major role in controlling bacterial biomass and regulating nutrient cycling in the environment. Little is known, however, about the movement of carbon from specific reduced substrates, through functional groups of bacteria, to particular clades of protozoa. In this study we first identified the active protozoan phylotypes present in activated sludge, via the construction of an rRNA-derived eukaryote clone library. Most of the sequences identified belonged to ciliates of the subclass Peritrichia and amoebae, confirming the dominance of surface-associated protozoa in the activated sludge environment. We then demonstrated that 13C-labeled protozoan RNA can be retrieved from activated sludge amended with 13C-labeled protozoa or 13C-labeled Escherichia coli cells by using an RNA stable isotope probing (RNA-SIP) approach. Finally, we used RNA-SIP to track carbon from bicarbonate and acetate into protozoa under ammonia-oxidizing and denitrifying conditions, respectively. RNA-SIP analysis revealed that the peritrich ciliate Epistylis galea dominated the acquisition of carbon from bacteria with access to CO2 under ammonia-oxidizing conditions, while there was no evidence of specific grazing on acetate consumers under denitrifying conditions.

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Eberhard, Mark L. « Atlas of Human Protozoa (Atlas dei Protozoi Umani) ». American Journal of Tropical Medicine and Hygiene 50, n^o 3 (1 mars 1994) : 392. http://dx.doi.org/10.4269/ajtmh.1994.50.392.

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Ayemele, Aurele Gnetegha, Lu Ma, Xiumei Li, Peilong Yang, Jianchu Xu, Zhongtang Yu et Dengpan Bu. « Identification of Bioactive Phytochemicals from Six Plants : Mechanistic Insights into the Inhibition of Rumen Protozoa, Ammoniagenesis, and α-Glucosidase ». Biology 10, n^o 10 (18 octobre 2021) : 1055. http://dx.doi.org/10.3390/biology10101055.

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Rumen protozoa prey on feed-degrading bacteria synthesizing microbial protein, lowering nitrogen utilization efficiency in ruminants. In this in vitro study, we evaluated six plants (Adansonia digitata, Flemingia macrophylla, Kalimeris indica,Brassica rapa subsp. chinensis, Portulaca oleracea, and Calotropis gigantea) for their potential to inhibit rumen protozoa and identified the phytochemicals potentially responsible for protozoa inhibition. Rumen protozoa were anaerobically cultured in vitro in the presence of each plant at four doses. All of the tested plants reduced total rumen protozoa (p ≤ 0.05), but C. gigantea and B. rapa were the most inhibitory, inhibiting rumen protozoa by 45.6 and 65.7%, respectively, at the dose of 1.1 mg/mL. Scanning electron microscopy revealed a disruption of the extracellular structure of protozoa cells. Only C. gigantea also decreased the wasteful ammoniagenesis (p ≤ 0.05). Moreover, the A. digitata extract inhibited α-glucosidase activity by about 70% at 100 µg/mL. Reversed-phase high-performance liquid chromatography analysis detected quercetin, anthraquinone, 3-hydroxybenzoic acid, astragaloside, and myricetin in the tested plant leaves. These plants may hold potential as feed additives to reduce rumen protozoa and α- glucosidase activity. Future research is needed to identify the specific anti-protozoal compound(s), the effects on the rumen microbiome, and its fermentation characteristics.

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NAGARAJA, T. G., S. J. GALITZER, D. L. HARMON et S. M. DENNIS. « EFFECT OF LASALOCID, MONENSIN AND THIOPEPTIN ON LACTATE PRODUCTION FROM IN VITRO RUMEN FERMENTATION OF STARCH ». Canadian Journal of Animal Science 66, n^o 1 (1 mars 1986) : 129–39. http://dx.doi.org/10.4141/cjas86-014.

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Starch fermentations with strained rumen fluid and centrifuged rumen fluid devoid of protozoa were set up to test the effect of lasalocid, monensin, and thiopeptin on L(+) and D(−) lactate production. Protozoa-free rumen fluid was the supernatant from low-speed centrifugation of strained rumen fluid. Starch fermentation in the control (no antibiotic) with centrifuged rumen fluid resulted in higher lactate concentration than the fermentation with strained rumen fluid. Decreased lactate production with strained rumen fluid was attributed to sequestration of starch by protozoa and to enhanced lactate fermentation. Addition of lasalocid or monensin (1.5–48.0 μg mL−1) to the fermentation enhanced L(+) and D(−) lactate production in the presence of protozoa. In the absence of protozoa, lasalocid and monensin inhibited L(+) lactate production; however, D(−) lactate concentration was unaffected. Increased lactate production by lasalocid and monensin in the presence of protozoa was possibly due to inhibition of protozoal engulfment of starch. Thiopeptin had no effect on lactate production in the presence of protozoa but in the absence of protozoa lactate production was inhibited. Similar antibiotic responses were observed at different starch amounts (0.5, 1.5 and 3.0 g) and with starch types (soluble, corn and wheat) and with rumen fluid collected from defaunated cattle. Key words: Antibiotics, cattle, rumen, starch, fermentation, lactic acid

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Situmorang, Fernando Jose Immanuel Clinton, Kholik Kholik, Candra Dwi Atma, Katty Hendriana Priscilia Riwu, Iwan Doddy Dharmawibawa et Munawer Pradana. « Identification of Gastrointestinal Protozoa of Sumatera Elephant (Elephas maximmus sumatranus) in Lombok Wildlife Park ». Bioscientist : Jurnal Ilmiah Biologi 12, n^o 1 (30 juin 2024) : 1454. http://dx.doi.org/10.33394/bioscientist.v12i1.11855.

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The protozoan parasites have been reported to infect Sumatran elephants. Gastrointestinal protozoa could potentially be a factor in the decline in the Sumatran elephant population in Indonesia. This study aims to identify the presence of gastrointestinal protozoa in Sumatran Elephant (Elephas maximus sumatranus) in the Lombok Wildlife Park, North Lombok Regency, Indonesia. This research has used fresh fecal samples from 5 Sumatran elephants. The examination of feces samples using native, sedimentation, and floating methods. The research results have identified the presence of gastrointestinal protozoa in 2 of the 5 Sumatran elephant feces examined. The gastrointestinal protozoa found were Eimeria spp with dimensions of 16.30 x 20.93 μm and 25.21 x 38.49 μm.

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Yuan, Guoqing, Yue Chen, Yulu Wang, Hanwen Zhang, Hongxia Wang, Mixue Jiang, Xiaonan Zhang, Yingchun Gong et Saibo Yuan. « Responses of Protozoan Communities to Multiple Environmental Stresses (Warming, Eutrophication, and Pesticide Pollution) ». Animals 14, n^o 9 (25 avril 2024) : 1293. http://dx.doi.org/10.3390/ani14091293.

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To explore the impacts of multiple environmental stressors on animal communities in aquatic ecosystems, we selected protozoa—a highly sensitive group of organisms—to assess the effect of environmental change. To conduct this simulation we conducted a three-factor, outdoor, mesocosm experiment from March to November 2021. Changes in the community structure and functional group composition of protozoan communities under the separate and combined effects of these three environmental stressors were investigated by warming and the addition of nitrogen, phosphorus, and pesticides. The results were as follows: (1) Both eutrophication and pesticides had a considerable promotional effect on the abundance and biomass of protozoa; the effect of warming was not considerable. When warming was combined with eutrophication and pesticides, there was a synergistic effect and antagonistic effect, respectively. (2) Eutrophication promoted α diversity of protozoa and affected their species richness and dominant species composition; the combination of warming and pesticides remarkably reduced the α diversity of protozoa. (3) Warming, eutrophication, and pesticides were important factors affecting the functional groups of protozoa. Interaction among different environmental factors could complicate changes in the aquatic ecological environment and its protozoan communities. Indeed, in the context of climate change, it might be more difficult to predict future trends in the protozoan community. Therefore, our results provide a scientific basis for the protection and restoration of shallow lake ecosystems; they also offer valuable insights in predicting changes in shallow lakes.

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Zhou, Yao, et Zhi Gang Xie. « The Study on Protozoan Community Structure of Zhalong Wetland ». Applied Mechanics and Materials 535 (février 2014) : 470–73. http://dx.doi.org/10.4028/www.scientific.net/amm.535.470.

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The zhalong wetland water environment is an important part of the ecological environment, The protozoan community structure of Zhalong wetland was researched in this article. We can monitoring water pollution degree through the analysis of protozoan population, this research investigated protozoa population structure in qiqihar zhalong wetland through the PFU method and direct mining water in water samples, and analyse the physiological and biochemical parameters to assess the quality of water quality changes during May-October in 2012, the result show that 74 protozoa were observed including ciliate fleshiness shrimp center, flagellate less. In comparison with clean water inside, can use light and feed on algae native species number is more, different water quality in different conditions, protozoa composition has a very significant difference.

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Nałęcz-Jawecki, Grzegorz, Milena Wawryniuk, Joanna Giebułtowicz, Adam Olkowski et Agata Drobniewska. « Influence of Selected Antidepressants on the Ciliated Protozoan Spirostomum ambiguum : Toxicity, Bioaccumulation, and Biotransformation Products ». Molecules 25, n^o 7 (25 mars 2020) : 1476. http://dx.doi.org/10.3390/molecules25071476.

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The present study aimed to evaluate the effect of the most common antidepressants on aquatic protozoa. Spirostomum ambiguum was used as the model protozoan. The biological activity of four antidepressants, namely fluoxetine, sertraline, paroxetine, and mianserin, toward S. ambiguum was evaluated. Sertraline was found to be the most toxic drug with EC50 values of 0.2 to 0.7 mg/L. The toxicity of the antidepressants depended on the pH of the medium and was the highest in alkaline conditions. Sertraline was also the most bioaccumulating compound tested, followed by mianserin. Slow depuration was observed after transferring the protozoa from the drug solutions to a fresh medium, which indicated possible lysosomotropism of the tested antidepressants in the protozoa. The biotransformation products were identified using a high-resolution mass spectrometer after two days of incubation of the protozoa with the tested antidepressants. Four to six potential biotransformation products were observed in the aqueous phase, while no metabolites were detected in the protozoan cells. Because of the low abundance of metabolites in the medium, their structure was not determined.

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Lee, Sung S., Jong K. Ha et K. J. Cheng. « The effects of sequential inoculation of mixed rumen protozoa on the degradation of orchard grass cell walls by anaerobic fungus Anaeromyces mucronatus 543 ». Canadian Journal of Microbiology 47, n^o 8 (1 août 2001) : 754–60. http://dx.doi.org/10.1139/w01-076.

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The effects of protozoa on the degradation of plant cell walls (CW) during different growth stages of the fungus Anaeromyces mucronatus have been investigated. Since fungi show a marked lag in their in vitro cultures and many protozoa rapidly die during a prolonged incubation time, the effects of protozoa may vary according to the growth phase of the fungi. Therefore, the approach adopted was (i) to inoculate CW with fungus monoculture, (ii) to inoculate CW with fungus-protozoa coculture, or (iii) to sequentially inoculate fungal cultures that had been grown in CW for 24 (initial stage of growth), 48, and 72 h (late stage of growth) with mixed protozoa. When a fungus was associated with protozoa, a growth phase dependent effect was observed. Ruminal protozoa adversely affected the growth and activity when introduced in the initial growth stage of A. mucronatus, but a synergetic interaction was detected when added to late growth stage cultures. Although there is no immediate explanation for these results, the data suggested that protozoa can engulf the fungal zoospores, which are in ruminal fluids and (or) attached to small feed particles, but cannot engulf the fungal thallus that is tightly attached to feed particles by a rhizoidal system. Our data indicated that the protozoa did not influence cellulolysis by the fungi in exponential and (or) stationary phase, but they had a marked inhibitory effect on fungi that were in lag phase. Inhibition during lag phase could result from the protozoal predation of fungal zoospores that had failed to attach to substrates.Key words: rumen fungi, rumen protozoa, cellulose digestion, cellulase activity, interactions.

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Muhoro, Arthur M., et Edit É. Farkas. « Insecticidal and Antiprotozoal Properties of Lichen Secondary Metabolites on Insect Vectors and Their Transmitted Protozoal Diseases to Humans ». Diversity 13, n^o 8 (26 juillet 2021) : 342. http://dx.doi.org/10.3390/d13080342.

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Since the long-term application of synthetic chemicals as insecticides and the chemotherapy of protozoal diseases have had various negative effects (non-target effects, resistance), research on less harmful biological products is underway. This review is focused on lichens with potential insecticidal and antiprotozoal activity. Literature sources (27) were surveyed from five bibliographic databases and analyzed according to the taxonomic group of the insect, the protozoal disease and the lichen, the type of bioactive compounds (including method of application and mount applied), and the potential bioactivity based on mortalities caused after 24 h of exposure on insects and on parasitic protozoa. Six species of protozoa and five species of mosquitoes, three kinds of larval stages of insects and three protozoa stages were tested. Insecticidal and antiprotozoal effects of crude extracts and seven lichen secondary metabolites (mostly usnic acid) of 32 lichen species were determined. Physiological and morphological changes on parasitic protozoa were observed. Mortality rates caused by LSMs on insect vectors closer to (or somewhat above) the WHO threshold were considered to be insecticides. The results are based on laboratory experiments; however, the efficacy of metabolites should be confirmed in the field and on non-human primates to control the insect vectors and human protozoal diseases transmitted by insects.

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Kujawinski, Elizabeth B., John W. Farrington et James W. Moffett. « Importance of Passive Diffusion in the Uptake of Polychlorinated Biphenyls by Phagotrophic Protozoa ». Applied and Environmental Microbiology 66, n^o 5 (1 mai 2000) : 1987–93. http://dx.doi.org/10.1128/aem.66.5.1987-1993.2000.

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ABSTRACT Unicellular protozoan grazers represent a size class of organisms where a transition in the mechanism of chlorobiphenyl (CB) introduction, from diffusion through surface membranes to ingestion of contaminated prey, could occur. This study compares the relative importance of these two processes in the overall uptake of polychlorinated biphenyls by protists. Uptake rates and steady-state concentrations were compared in laboratory cultures of grazing and nongrazing protozoa. These experiments were conducted with a 10-μm marine scuticociliate (Uronema sp.), bacterial prey (Halomonas halodurans), and a suite of 21 CB congeners spanning a range of aqueous solubilities. The dominant pathway of CB uptake by both grazing and nongrazing protozoa was diffusion. Organic-carbon-normalized CB concentrations (in the protozoan cell) were equivalent in grazing and nongrazing protozoa for all congeners studied. Rate constants for uptake into and loss from the protozoan cell were independently determined by using [3,3′,4,4′-14C]tetrachlorobiphenyl (IUPAC no. 77), 0.38 ± 0.03 min−1 and (1.1 ± 0.1) × 10−5 (g of organic carbon)−1min−1, respectively. Magnitudes of the uptake and loss processes were calculated and compared by using a numerical model. The model result was consistent with data from the bioaccumulation experiment and supported the hypothesis that diffusive uptake is faster than ingestive uptake in phagotrophic unicellular protozoa.

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Novitsky, James A. « Protozoa abundance, growth, and bacterivory in the water column, on sedimenting particles, and in the sediment of Halifax Harbor ». Canadian Journal of Microbiology 36, n^o 12 (1 décembre 1990) : 859–63. http://dx.doi.org/10.1139/m90-149.

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The role of protozoan grazing in controlling bacterial populations was examined in four microbial habitats in Halifax Harbor, Canada: the water column, setting particles, the sediment–water interface, and the sediment. Large numbers of protozoans were found in all habitats although most (>56%) were small (<5 μm) flagellates. Protozoans larger than 10 μm were rarely observed; protozoans >20 μm were never observed. Protozoans were also observed to a depth of 9 cm below the sediment surface although efforts to culture viable protozoa failed except for the top 1 cm. The use of the metabolic inhibitor cycloheximide with and without colchicine to selectively inhibit eucaryotic metabolism was shown to severely affect procaryotic metabolism in sediment (and presumably particle and water) samples. Using fluorescently labelled bacteria as food, and under optimum conditions, up to 42% of the Protozoa population exhibited active grazing within 7 h. Using protozoan and bacterial community sizes and doubling times, it was calculated that each protozoan in Halifax Harbor would have to consume 13–118 bacteria per hour for the enumerated nanoplanktonic (<20 μm) Protozoa to be the sole control of the size of the bacterial community. Key words: marine, Protozoa, bacterivory, particles, bacteria.

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Ivan, M., T. Entz, P. S. Mir, Z. Mir et T. A. McAllister. « Effects of sunflower seed supplementation and different dietary protein concentrations on the ciliate protozoa population dynamics in the rumen of sheep ». Canadian Journal of Animal Science 83, n^o 4 (1 décembre 2003) : 809–17. http://dx.doi.org/10.4141/a03-052.

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The effects of feeding a linoleic acid-rich sunflower seed supplement and different levels of dietary protein on protozoal numbers and fermentation parameters in rumen fluid were determined in an 84-d experiment with rumen-cannulated sheep. The experiment comprised four treatments, two with low crude protein diets [12% of dietary dry matter (DM)] and two with high protein diets (16% of DM). On both low and high protein diets, one treatment was without (Control) and one with the sunflower seed (high linoleic acid variety 6150) supplement (14% of dietary DM). The four diets used were based on corn silage and corn grain, and soybean meal was used to achieve the desired concentration of dietary protein. The sheep were fully fed each morning and rumen fluid samples were taken 2 h later on various days of the experiment (daily during the first 14 d for enumeration of protozoa). In addition, rumen fluid was sampled at different hours after feeding on day 43 of the experiment. Results showed a protozoa-decreasing effect (P < 0.001) of sunflower seeds causing a decline in protozoa numbers after 2 d of supplementation. The effect of protein on protozoa numbers was dependent on the presence of sunflower seed supplement. Measurements on day 43 showed increased protozoa numbers (P < 0.05) and ammonia nitrogen concentrations (P < 0.001) due to higher dietary protein, and decreased protozoal numbers (P < 0.05) and ammonia nitrogen (P < 0.001) due to the sunflower seed supplement, without significant effects (P > 0.05) on volatile fatty acid concentrations. The linoleic acid-rich sunflower seed supplement was highly effective in reducing both protozoa numbers and ammonia nitrogen concentrations in rumen fluid. Key words: Rumen ciliate protozoa, sunflower seeds, dietary protein, sheep

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DeMichele, Emily, Olivia Sosnowski, Andre G. Buret et Thibault Allain. « Regulatory Functions of Hypoxia in Host–Parasite Interactions : A Focus on Enteric, Tissue, and Blood Protozoa ». Microorganisms 11, n^o 6 (16 juin 2023) : 1598. http://dx.doi.org/10.3390/microorganisms11061598.

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Body tissues are subjected to various oxygenic gradients and fluctuations and hence can become transiently hypoxic. Hypoxia-inducible factor (HIF) is the master transcriptional regulator of the cellular hypoxic response and is capable of modulating cellular metabolism, immune responses, epithelial barrier integrity, and local microbiota. Recent reports have characterized the hypoxic response to various infections. However, little is known about the role of HIF activation in the context of protozoan parasitic infections. Growing evidence suggests that tissue and blood protozoa can activate HIF and subsequent HIF target genes in the host, helping or hindering their pathogenicity. In the gut, enteric protozoa are adapted to steep longitudinal and radial oxygen gradients to complete their life cycle, yet the role of HIF during these protozoan infections remains unclear. This review focuses on the hypoxic response to protozoa and its role in the pathophysiology of parasitic infections. We also discuss how hypoxia modulates host immune responses in the context of protozoan infections.

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Barzegar, Maryam, Mehdi Raissy et Shokoofeh Shamsi. « Protozoan Parasites of Iranian Freshwater Fishes : Review, Composition, Classification, and Modeling Distribution ». Pathogens 12, n^o 5 (27 avril 2023) : 651. http://dx.doi.org/10.3390/pathogens12050651.

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This article investigates the occurrence and distribution of parasitic protozoa of Iranian freshwater fishes (both farmed and wild). Our search shows 26 known parasitic protozoan species were recorded from 52 freshwater fish species across different ecoregions of Iran. Most of these fish are edible. While none of the identified protozoan parasites are of zoonotic importance, our study does not exclude presence of zoonotic species in Iranian fishes. Present data suggest the northern and western regions of the country are the main macrohabitat of protozoa (35 parasitic records reported), with the greatest concentration of parasitic protozoa occurring in the Urmia basin in Iran’s northwest. The clustered distribution pattern of protozoa among freshwater fish was also more evident in the northern and western parts of the country. The gills and skin were the most infected microhabitats for parasitic protozoa. The highest number of parasites was observed in the fish family Cyprinidae with nine species found in the native fish, Capoeta capoeta. The most diverse host range was observed in the holotrich ciliate, Ichthyophthirius multifiliis isolated from 46 cyprinid species in 39 different locations. However, due to the great richness of fish and extreme habitat diversity, parts of the parasite fauna of Iranian freshwater fish are still poorly understood. Furthermore, current and future changes in climate and environmental parameters, and anthropogenic interventions are likely to affect fish hosts and their parasites.

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INGHAM, ELAINE R. « Soil Protozoa ». Soil Science 159, n^o 4 (avril 1995) : 281–82. http://dx.doi.org/10.1097/00010694-199504000-00009.

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