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Anaerobe Jun 2024Ciliate protozoa are key members of the microbial community of the rumen. Their study is important to the health and productivity of cattle, which are their hosts.... (Review)
Review
Ciliate protozoa are key members of the microbial community of the rumen. Their study is important to the health and productivity of cattle, which are their hosts. However, there have been persistent challenges in culturing this microbial group in the laboratory. This review will sum up recent advances along with these persistent challenges. Protozoa have been maintained in three types of cultures (ex vivo, in vitro batch, in vitro continuous). Ex vivo cultures are prepared readily from rumen contents by washing away contaminating cells (e.g., bacteria). They have been useful in making basic observations of metabolism, such as which types of fermentation products protozoa form. However, these cultures can be maintained for only short periods (minutes or hours). In vitro batch and in vitro continuous cultures can be used in longer experiments (weeks or longer). However, it is not currently possible to maintain protozoa in these cultures unless bacteria are also present. We conclude the review with a protocol for preparing ex vivo cultures of protozoa. Our protocol has been standardized and used successfully across animal diets, users, and institutions. We anticipate this review will prepare others to culture rumen ciliate protozoa and reach new insights into this important microbial group.
Topics: Rumen; Animals; Ciliophora; Cattle
PubMed: 38782297
DOI: 10.1016/j.anaerobe.2024.102865 -
The Journal of Nutrition Apr 1996Results obtained during the past decade indicate clearly that protozoa are actively involved in the degradation of dietary and microbial proteins in the rumen. Because... (Review)
Review
Results obtained during the past decade indicate clearly that protozoa are actively involved in the degradation of dietary and microbial proteins in the rumen. Because of the great ability of protozoa to ingest the particulate matter suspended in the rumen, protozoa are more active in degrading insoluble than soluble proteins. This indicates that studies carried out using lysed and sonicated protozoa are not appropriate for quantifying the actual contribution of protozoa to protein degradation in the rumen. In vivo trials have confirmed that duodenal flow of both undegraded dietary protein plus bacterial protein generally is increased by defaunation. The decrease in ruminal ammonia concentration consistently observed after defaunation accounts for the lower urinary nitrogen (N) excretion found in defaunated animals, whereas the increase in fecal N excretion in the same animals probably results from a shift of plant cell wall digestion from the rumen to the large intestine. Total N excretion is not altered significantly by defaunation. A summary of literature data indicates there are contradictory effects of defaunation on ruminant performance. This implies that animal response to defaunation may depend on the specific nutrient-limiting performance on the one hand and on the modifications of digestion and metabolism resulting from defaunation on the other. Different methods are proposed to either eliminate or decrease the numbers of ruminal protozoa or to alter their makeup. However, none of these approaches has been tested under practical feeding conditions.
Topics: Animals; Dietary Proteins; Eukaryota; Nitrogen; Rumen; Ruminants
PubMed: 8642481
DOI: 10.1093/jn/126.suppl_4.1335S -
American Family Physician Jun 1996Giardia is the best known cause of protozoal gastrointestinal disease in North America, producing significant but not life-threatening gastrointestinal distress and... (Review)
Review
Giardia is the best known cause of protozoal gastrointestinal disease in North America, producing significant but not life-threatening gastrointestinal distress and diarrhea. Although diagnosis of giardiasis may be challenging, treatment is usually successful. Entamoeba histolytica poses a rarer but far more difficult clinical challenge. Dysentery caused by E. histolytica may be the most feared intestinal protozoal infection, although Cryptosporidium parvum, Balantidium coli, Isospora belli, Sarcocystis species and other newly described protozoa also may cause diarrhea in healthy individuals and may result in intractable, life-threatening illness in patients with acquired immunodeficiency syndrome or other immunosuppressive diseases. Certain protozoa once considered relatively unimportant, such as Cryptosporidium, are now recognized as significant causes of morbidity even in the United States, since transmission readily occurs through contaminated water.
Topics: Balantidiasis; Cryptosporidiosis; Dientamoebiasis; Giardiasis; Humans; Intestinal Diseases, Parasitic
PubMed: 8644565
DOI: No ID Found -
Journal of Medical Microbiology Jan 1997
Review
Topics: Animals; Cryptosporidiosis; Giardiasis; Humans; Toxoplasmosis; Zoonoses
PubMed: 9003740
DOI: No ID Found -
FEMS Microbiology Reviews Jul 2010Neuropathogenic protozoa have evolved strategies to breach the blood-brain barrier and invade the central nervous system. These include transcellular, paracellular and... (Review)
Review
Neuropathogenic protozoa have evolved strategies to breach the blood-brain barrier and invade the central nervous system. These include transcellular, paracellular and the Trojan horse routes but the associated molecular mechanisms remain incompletely understood. Here, we summarize the current understanding of protozoa penetration across the blood-brain barrier, focusing on Plasmodium, Babesia, Trypanosoma, Toxoplasma, Acanthamoeba and Balamuthia. Advances in understanding the molecular pathways will offer opportunities for the rational development of novel therapeutic interventions.
Topics: Amoebozoa; Apicomplexa; Blood-Brain Barrier; Central Nervous System Parasitic Infections; Humans; Trypanosoma
PubMed: 20337721
DOI: 10.1111/j.1574-6976.2010.00215.x -
Expert Review of Molecular Diagnostics Nov 2014Robust detection of enteric protozoa is a critical step toward determining the etiology of diarrhea. Widespread use of conventional microscopy, culturing and antigen... (Review)
Review
Robust detection of enteric protozoa is a critical step toward determining the etiology of diarrhea. Widespread use of conventional microscopy, culturing and antigen detection in both industrial and developing countries is limited by relatively low sensitivity and specificity. Refinements of these conventional approaches that reduce turnaround time and instrumentation have yielded strong alternatives for clinical and research use. However, advances in molecular diagnostics for protozoal, bacterial, viral and helminth infections offer significant advantages in studies seeking to understand pathogenesis, transmission and long-term consequences of infectious diarrhea. Quantitation of enteropathogen burden and highly multiplexed platforms for molecular detection dramatically improve predictive power in emerging models of diarrheal etiology, while eliminating the expense of multiple tests.
Topics: Animals; Diarrhea; Humans; Molecular Diagnostic Techniques; Parasites
PubMed: 25139776
DOI: 10.1586/14737159.2014.951035 -
[Progress of research on the interplay between helminth and intestinal protozoa and gut microbiota].Zhongguo Xue Xi Chong Bing Fang Zhi Za... Mar 2019As the largest and most complex ecosystem in humans, gut microbiota resides in human or animal gastrointestinal tract with intestinal viruses and parasites. Previous... (Review)
Review
As the largest and most complex ecosystem in humans, gut microbiota resides in human or animal gastrointestinal tract with intestinal viruses and parasites. Previous studies have demonstrated that gut microbiotadysbiosis is strongly correlated with the development, progression and prognosis of multiple diseases. The parasites that are colonized in the host, may directly or indirectly affect gut microbiota and the gut microbiota-host homeostasis, and changes in the composition and diversity of gut microbiota may also affect parasitic infections and the development, progression and prognosis of parasitic diseases. This paper reviews the progress of research on the interplay between helminth and intestinal protozoa and gut microbiota.
Topics: Animals; Gastrointestinal Microbiome; Gastrointestinal Tract; Helminths; Homeostasis; Humans; Intestines; Research
PubMed: 31016928
DOI: 10.16250/j.32.1374.2019005 -
Advances in Parasitology 1978
Review
Topics: Animals; Cell Nucleus; Cells, Cultured; Cytoplasmic Granules; Humans; Mammals; Microtubules; Mitochondria; Muscles; Sarcocystis; Sarcocystosis; Spores
PubMed: 103377
DOI: 10.1016/s0065-308x(08)60572-2 -
Memorias Do Instituto Oswaldo Cruz Feb 2013Paleoparasitological research has made important contributions to the understanding of parasite evolution and ecology. Although parasitic protozoa exhibit a worldwide... (Review)
Review
Paleoparasitological research has made important contributions to the understanding of parasite evolution and ecology. Although parasitic protozoa exhibit a worldwide distribution, recovering these organisms from an archaeological context is still exceptional and relies on the availability and distribution of evidence, the ecology of infectious diseases and adequate detection techniques. Here, we present a review of the findings related to protozoa in ancient remains, with an emphasis on their geographical distribution in the past and the methodologies used for their retrieval. The development of more sensitive detection methods has increased the number of identified parasitic species, promising interesting insights from research in the future.
Topics: Animals; Feces; Fossils; History, Ancient; Humans; Paleopathology; Protozoan Infections
PubMed: 23440107
DOI: 10.1590/s0074-02762013000100001 -
Nature Immunology Nov 2002Parasitic protozoa are a major cause of global infectious disease. These eukaryotic pathogens have evolved with the vertebrate immune system and typically produce... (Review)
Review
Parasitic protozoa are a major cause of global infectious disease. These eukaryotic pathogens have evolved with the vertebrate immune system and typically produce long-lasting chronic infections. A critical step in their host interaction is the evasion of innate immune defenses. The ability to avoid attack by humoral effector mechanisms, such as complement lysis, is of particular importance to extracellular parasites, whereas intracellular protozoa must resist killing by lysosomal enzymes and toxic metabolites. They do so by remodeling the phagosomal compartments in which they reside and by interfering with signaling pathways that lead to cellular activation. In addition, there is growing evidence that protozoan pathogens modify the antigen-presenting and immunoregulatory functions of dendritic cells, a process that facilitates their evasion of both innate and adaptive immunity.
Topics: Animals; Antigen Presentation; Antigens, Protozoan; Cattle; Cattle Diseases; Child; Dendritic Cells; Eukaryota; Host-Parasite Interactions; Humans; Immunity, Innate; Insect Vectors; Interleukin-12; Leishmania; Mice; Phagosomes; Protozoan Infections; Protozoan Infections, Animal; Signal Transduction; Toxoplasma; Trypanosoma
PubMed: 12407413
DOI: 10.1038/ni1102-1041