1
|
Oxygen levels are key to understanding "Anaerobic" protozoan pathogens with micro-aerophilic lifestyles. Adv Microb Physiol 2021; 79:163-240. [PMID: 34836611 DOI: 10.1016/bs.ampbs.2021.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Publications abound on the physiology, biochemistry and molecular biology of "anaerobic" protozoal parasites as usually grown under "anaerobic" culture conditions. The media routinely used are poised at low redox potentials using techniques that remove O2 to "undetectable" levels in sealed containers. However there is growing understanding that these culture conditions do not faithfully resemble the O2 environments these organisms inhabit. Here we review for protists lacking oxidative energy metabolism, the oxygen cascade from atmospheric to intracellular concentrations and relevant methods of measurements of O2, some well-studied parasitic or symbiotic protozoan lifestyles, their homeodynamic metabolic and redox balances, organism-drug-oxygen interactions, and the present and future prospects for improved drugs and treatment regimes.
Collapse
|
2
|
Gossypol Exhibited Higher Detrimental Effect on Ruminal Fermentation Characteristics of Low-Forage in Comparison with High-Forage Mixed Feeds. TOXICS 2021; 9:toxics9030051. [PMID: 33800444 PMCID: PMC7999078 DOI: 10.3390/toxics9030051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 11/17/2022]
Abstract
Gossypol is a key anti-nutritional factor which limits the feeding application of cottonseed by-products in animal production. A 2 × 4 factorial in vitro experiment was conducted to determine the effect of gossypol addition levels of 0, 0.25, 0.5, and 0.75 mg/g on ruminal fermentation of a high-forage feed (HF, Chinese wildrye hay/corn meal = 3:2) in comparison with a low-forage feed (LF, Chinese wildrye hay/corn meal = 2:3). After 48 h of incubation, in vitro dry matter disappearance was greater in the LF than the HF group, while the cumulative gas production and asymptotic gas production were greater in the HF than the LF group (p < 0.05). Regardless of whatever ration type was incubated, the increasing gossypol addition did not alter in vitro dry matter disappearance. The asymptotic gas production, cumulative gas production, molar percentage of CO2 and H2 in fermentation gases, and microbial protein in cultural fluids decreased with the increase in the gossypol addition. Conversely, the gossypol addition increased the molar percentage of CH4, ammonia N, and total volatile fatty acid production. More than 95% of the gossypol addition disappeared after 48 h of in vitro incubation. Regardless of whatever ration type was incubated, the real-time PCR analysis showed that the gossypol addition decreased the populations of Fibrobactersuccinogenes, Ruminococcus albus, Butyrivibrio fibrisolvens, Prevotella ruminicola, Selenomonas ruminantium, and fungi but increased Ruminococcus flavefaciens, protozoa, and total bacteria in culture fluids in comparison with the control (p < 0.01). Additionally, the tendency of a smaller population was observed for R. albus, B. fibrisolvens, and fungi with greater inclusion of gossypol, but a greater population was observed for F. succinogenes, R. flavefaciens, S. ruminantium, protozoa, and total bacteria. In summary, the present results suggest that rumen microorganisms indeed presented a high ability to degrade gossypol, but there was an obvious detrimental effect of the gossypol addition on rumen fermentation by decreasing microbial activity when the gossypol inclusion exceeded 0.5 mg/g, and such inhibitory effect was more pronounced in the low-forage than the high-forage group.
Collapse
|
3
|
Park T, Yu Z. Aerobic cultivation of anaerobic rumen protozoa, Entodinium caudatum and Epidinium caudatum. J Microbiol Methods 2018; 152:186-193. [DOI: 10.1016/j.mimet.2018.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 08/09/2018] [Accepted: 08/15/2018] [Indexed: 11/26/2022]
|
4
|
Fenchel T. Anaerobic Eukaryotes. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2012. [DOI: 10.1007/978-94-007-1896-8_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
5
|
Marco D. Metagenomics and the niche concept. Theory Biosci 2008; 127:241-7. [PMID: 18421492 DOI: 10.1007/s12064-008-0028-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Accepted: 03/20/2008] [Indexed: 10/22/2022]
Abstract
The metagenomics approach has revolutionised the fields of bacterial diversity, ecology and evolution, as well as derived applications like bioremediation and obtaining bioproducts. A further associated conceptual change has also occurred since in the metagenomics methodology the species is no longer the unit of study, but rather partial genome arrangements or even isolated genes. In spite of this, concepts coming from ecological and evolutionary fields traditionally centred on the species, like the concept of niche, are still being applied without further revision. A reformulation of the niche concept is necessary to deal with the new operative and epistemological challenges posed by the metagenomics approach. To contribute to this end, I review past and present uses of the niche concept in ecology and in microbiological studies, showing that a new, updated definition need to be used in the context of the metagenomics. Finally, I give some insights into a more adequate conceptual background for the utilisation of the niche concept in metagenomic studies. In particular, I raise the necessity of including the microbial genetic background as another variable into the niche space.
Collapse
Affiliation(s)
- Diana Marco
- Laboratorio de Ecología, Area de Producción Orgánica, Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Ciudad Universitaria, Av. Valparaiso s/n, Córdoba, CP 5000, CC 508, Argentina.
| |
Collapse
|
6
|
Lloyd D. 'Anaerobic protists': some misconceptions and confusions. MICROBIOLOGY-SGM 2004; 150:1115-1116. [PMID: 15133067 DOI: 10.1099/mic.0.26802-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- David Lloyd
- Cardiff School of Biosciences, Cardiff University, Main Building, PO Box 915, Cardiff CF1 3TL, UK
| |
Collapse
|
7
|
Embley TM, van der Giezen M, Horner DS, Dyal PL, Foster P. Mitochondria and hydrogenosomes are two forms of the same fundamental organelle. Philos Trans R Soc Lond B Biol Sci 2003; 358:191-201; discussion 201-2. [PMID: 12594927 PMCID: PMC1693103 DOI: 10.1098/rstb.2002.1190] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Published data suggest that hydrogenosomes, organelles found in diverse anaerobic eukaryotes that make energy and hydrogen, were once mitochondria. As hydrogenosomes generally lack a genome, the conversion is probably one way. The sources of the key hydrogenosomal enzymes, pyruvate : ferredoxin oxidoreductase (PFO) and hydrogenase, are not resolved by current phylogenetic analyses, but it is likely that both were present at an early stage of eukaryotic evolution. Once thought to be restricted to a few unusual anaerobic eukaryotes, the proteins are intimately integrated into the fabric of diverse eukaryotic cells, where they are targeted to different cell compartments, and not just hydrogenosomes. There is no evidence supporting the view that PFO and hydrogenase originated from the mitochondrial endosymbiont, as posited by the hydrogen hypothesis for eukaryogenesis. Other organelles derived from mitochondria have now been described in anaerobic and parasitic microbial eukaryotes, including species that were once thought to have diverged before the mitochondrial symbiosis. It thus seems possible that all eukaryotes may eventually be shown to contain an organelle of mitochondrial ancestry, to which different types of biochemistry can be targeted. It remains to be seen if, despite their obvious differences, this family of organelles shares a common function of importance for the eukaryotic cell, other than energy production, that might provide the underlying selection pressure for organelle retention.
Collapse
Affiliation(s)
- T Martin Embley
- Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.
| | | | | | | | | |
Collapse
|
8
|
Temesvári P, Kerekes A, Tege A, Szarka K. Demonstration of Trichomonas vaginalis in tracheal aspirates in infants with early respiratory failure. J Matern Fetal Neonatal Med 2002; 11:347-9. [PMID: 12389679 DOI: 10.1080/jmf.11.5.347.349] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Trichomonas vaginalis was isolated from the tracheal aspirates of two premature newborns with early respiratory failure who were delivered vaginally by mothers with T. vaginalis infection. The babies were treated successfully with antiparasitic drugs.
Collapse
Affiliation(s)
- P Temesvári
- Department of Pediatrics, University Teaching Hospital, Kecskemét, Hungary
| | | | | | | |
Collapse
|
9
|
Lloyd D, Ralphs JR, Harris JC. Giardia intestinalis, a eukaryote without hydrogenosomes, produces hydrogen. MICROBIOLOGY (READING, ENGLAND) 2002; 148:727-733. [PMID: 11882707 DOI: 10.1099/00221287-148-3-727] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The microaerophilic flagellated protist Giardia intestinalis, the commonest protozoal agent of intestinal infections worldwide, is of uncertain phylogeny, but is usually regarded as the earliest branching of the eukaryotic clades. Under strictly anaerobic conditions, a mass spectrometric investigation of gas production indicated a low level of generation of dihydrogen (2 nmol x min(-1) per 10(7) organisms), about 10-fold lower than that in Trichomonas vaginalis under similar conditions. Hydrogen evolution was O2 sensitive, and inhibited by 100 microM metronidazole. Fluorescent labelling of G. intestinalis cells using monoclonal antibodies to typical hydrogenosomal enzymes from T. vaginalis (malate enzyme, and succinyl-CoA synthetase alpha and beta subunits), and to the large-granule fraction (hydrogenosome-enriched, also from T. vaginalis) gave no discrete localization of epitopes. Cell-free extracts prepared under anaerobic conditions showed the presence of a CO-sensitive hydrogenase activity. This first report of hydrogen production in a eukaryote with no recognizable hydrogenosomes raises further questions about the early branching status of G. intestinalis; the physiological characterization of its hydrogenase, and its recently elucidated gene sequence, will aid further phylogenetic investigations.
Collapse
Affiliation(s)
- David Lloyd
- Microbiology (BIOSI 1, Main Building), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - James R Ralphs
- Microbiology (BIOSI 1, Main Building), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| | - Janine C Harris
- Microbiology (BIOSI 1, Main Building), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1
| |
Collapse
|
10
|
Abstract
The phylogeny of the commonest protozoal agent of intestinal disease, Giardia, is unclear. Although recent intensive research suggests this important human parasite is an early branching eukaryote that evolved before the endosymbiotic origin of mitochondria, there is also evidence to suggest that, as a highly evolved parasite, it has lost many of its ancestral characteristics. In this case, these organisms might have arisen much more recently from aerobic free-living flagellates.
Collapse
Affiliation(s)
- David Lloyd
- Microbiology (BIOSI), Cardiff University, PO Box 915, Wales, CF10 3TL., Cardiff, UK.
| | | |
Collapse
|
11
|
Biagini GA, McIntyre PS, Finlay BJ, Lloyd D. Carbohydrate and Amino Acid Fermentation in the Free-Living Primitive Protozoon Hexamita sp. Appl Environ Microbiol 1998; 64:203-7. [PMID: 16349480 PMCID: PMC124694 DOI: 10.1128/aem.64.1.203-207.1998] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/1997] [Accepted: 10/27/1997] [Indexed: 11/20/2022] Open
Abstract
Hexamita sp. is an amitochondriate free-living diplomonad which inhabits O(2)-limited environments, such as the deep waters and sediments of lakes and marine basins. C nuclear magnetic resonance spectroscopy reveals ethanol, lactate, acetate, and alanine as products of glucose fermentation under microaerobic conditions (23 to 34 muM O(2)). Propionic acid and butyric acid were also detected and are believed to be the result of fermentation of alternative substrates. Production of organic acids was greatest under microaerobic conditions (15 muM O(2)) and decreased under anaerobic (<0.25 muM O(2)) and aerobic (200 to 250 muM O(2)) conditions. Microaerobic incubation resulted in the production of high levels of oxidized end products (70% acetate) compared to that produced under anoxic conditions (20% acetate). In addition, data suggest that Hexamita cells contain the arginine dihydrolase pathway, generating energy from the catabolism of arginine to citrulline, ornithine, NH(4), and CO(2). The rate of arginine catabolism was higher under anoxic conditions than under microaerobic conditions. Hexamita cells were able to grow in the absence of a carbohydrate source, albeit with a lower growth rate and yield.
Collapse
Affiliation(s)
- G A Biagini
- Microbiology Group, School of Pure and Applied Biology, University of Wales College of Cardiff, Cardiff CF1 3TL, and School of Applied Sciences, University of Glamorgan, Pontypridd, Mid Glamorgan CF37 1DL, Wales, and Institute of Freshwater Ecology, Windermere Laboratory, The Ferry House, Ambleside, Cumbria LA22 OLP, United Kingdom
| | | | | | | |
Collapse
|
12
|
Biagini GA, Suller MT, Finlay BJ, Lloyd D. Oxygen uptake and antioxidant responses of the free-living diplomonad Hexamita sp. J Eukaryot Microbiol 1997; 44:447-53. [PMID: 9304813 DOI: 10.1111/j.1550-7408.1997.tb05722.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The free-living anaerobic flagellate Hexamita sp. was observed to actively consume O2 with a K(m) O2 of 13 microM. Oxygen consumption increased linearly with O2 tension up to a threshold level of 100 microM, above which it was inhibited. Oxygen uptake was supported by a number of substrates but probably not coupled to energy conservation as cytochromes could not be detected spectro-photometrically. In addition, inhibitors specific for respiratory chain components did not significantly affect O2 uptake. Respiration was however, partially inhibited by flavoprotein and iron-sulfur protein inhibitors. NAD(P)H supported O2 consumption was measured in both particulate and soluble fractions; this activity was partially inhibited by quinacrine. A chemosensory response was observed in cells exposed to air, however no response was observed in the presence of superoxide dismutase plus catalase. Catalase and nonspecific peroxidase activity could not be detected, but superoxide dismutase plus catalase. Catalase and nonspecific peroxidase activity could not be detected, but superoxide dismutase activity was present. Superoxide dismutase was sensitive to NaN3, and H2O2 but not KCN, suggesting a Fe prosthetic group. Flow cytometric analysis revealed that thiol levels in live cells were depleted in the presence of t-butyl H2O2. The observed NADPH-driven glutathione reductase activity is believed to recycle oxidized thiols in order to re-establish reduced thiol levels in the cell. The corresponding thiol cycling enzyme glutathione peroxidase could not be detected. The ability to withstand high O2 tensions (100 microM) would enable Hexamita to spend short periods in a wider range of habitats. Prolonged exposure to O2 tensions higher than 100 microM leads to irreversible damage and cell death.
Collapse
Affiliation(s)
- G A Biagini
- Microbiology Group, PABIO, University of Wales College of Cardiff, United Kingdom.
| | | | | | | |
Collapse
|
13
|
|
14
|
Williams A, Withers S, Naylor G, Joblin K. Effect of heterotrophic ruminal bacteria on xylan metabolism by the anaerobic fungus Piromyces communis. Lett Appl Microbiol 1994. [DOI: 10.1111/j.1472-765x.1994.tb00917.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
15
|
Williams A, Withers S, Orpin C. Effect of the carbohydrate growth substrate on polysaccharolytic enzyme formation by anaerobic fungi isolated from the foregut and hindgut of nonruminant herbivores and the forestomach of ruminants. Lett Appl Microbiol 1994. [DOI: 10.1111/j.1472-765x.1994.tb00830.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|