Flavohemoglobin and nitric oxide detoxification in the human protozoan parasite Giardia intestinalis

2010 ◽  
Vol 399 (4) ◽  
pp. 654-658 ◽  
Author(s):  
Daniela Mastronicola ◽  
Fabrizio Testa ◽  
Elena Forte ◽  
Eugenio Bordi ◽  
Leopoldo Paolo Pucillo ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protozoan Parasite ◽  
Giardia Intestinalis ◽  
Nitric Oxide Detoxification

The role of Bradyrhizobium japonicum nitric oxide reductase in nitric oxide detoxification in soya bean root nodules

2006 ◽  
Vol 34 (1) ◽  
pp. 195-196 ◽  
Author(s):  
G.E. Meakin ◽  
B.J.N. Jepson ◽  
D.J. Richardson ◽  
E.J. Bedmar ◽  
M.J. Delgado
Keyword(s):  
Nitric Oxide ◽  
Bradyrhizobium Japonicum ◽  
Root Nodules ◽  
Soya Bean ◽  
Nitric Oxide Reductase ◽  
Bean Root ◽  
Detoxification Systems ◽  
Nitric Oxide Detoxification

The identification of nitric oxide-bound leghaemoglobin within soya bean nodules has led to the question of how Bradyrhizobium japonicum bacteroids overcome the toxicity of this nitric oxide. It has previously been shown that one candidate for nitric oxide detoxification, the respiratory nitric oxide reductase, is expressed in soya bean nodules from plants supplied with nitrate [Mesa, de Dios Alché, Bedmar and Delgado (2004) Physiol. Plant. 120, 205–211]. In this paper, the role of this enzyme in nitric oxide detoxification is assessed and discussion is provided on other possible B. japonicum nitric oxide detoxification systems.

scholarly journals Cell Cycle Synchrony in Giardia intestinalis Cultures Achieved by Using Nocodazole and Aphidicolin

2008 ◽  
Vol 7 (4) ◽  
pp. 569-574 ◽  
Author(s):  
Marianne K. Poxleitner ◽  
Scott C. Dawson ◽  
W. Zacheus Cande
Keyword(s):  
Cell Cycle ◽  
Model Organism ◽  
Protozoan Parasite ◽  
Giardia Intestinalis ◽  
Mitotic Spindles ◽  
Intestinal Protozoan ◽  
Cycle Arrest ◽  
Cycle Dependent ◽  
Dependent Processes

ABSTRACT Giardia intestinalis is a ubiquitous intestinal protozoan parasite and has been proposed to represent the earliest diverging lineage of extant eukaryotes. Despite the importance of Giardia as a model organism, research on Giardia has been hampered by an inability to achieve cell cycle synchrony for in vitro cultures. This report details successful methods for attaining cell cycle synchrony in Giardia cultures. The research presented here demonstrates reversible cell cycle arrest in G1/S and G2/M with aphidicolin and nocodazole, respectively. Following synchronization, cells were able to recover completely from drug treatment and remained viable and maintained synchronous growth for 6 h. These techniques were used to synchronize Giardia cultures to increase the percentages of mitotic spindles in the cultures. This method of synchronization will enhance our ability to study cell cycle-dependent processes in G. intestinalis.

scholarly journals A critical assessment of two real-time PCR assays targeting the (SSU) rRNA and gdh genes for the molecular identification of Giardia intestinalis in a clinical laboratory

2014 ◽  
Vol 67 (9) ◽  
pp. 811-816 ◽  
Author(s):  
Samuel Boadi ◽  
Spencer D Polley ◽  
Sally Kilburn ◽  
Graham A Mills ◽  
Peter L Chiodini
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Clinical Laboratory ◽  
Protozoan Parasite ◽  
Molecular Techniques ◽  
Giardia Intestinalis ◽  
Diagnostic Sensitivity ◽  
Rrna Gene ◽  
Ssu Rrna ◽  
Pcr Assays

IntroductionGiardiasis is an intestinal diarrhoeal illness caused by the flagellate protozoan parasite Giardia intestinalis. Molecular techniques for the identification of G. intestinalis have generally been shown to offer a better detection rate of the parasite than the traditional faecal concentration and microscopy techniques.AimThe aim of this study was to critically assess the performance of a commercial and a published real-time PCR assay for their potential use as frontline tests for the diagnosis of giardiasis.MethodsA composite reference standard of enzyme immunoassay and rapid membrane test was used in a diagnostic accuracy study to assess the performance of Primerdesign's, and Verweij et alG. intestinalis real-time PCR assays, comparing them with the traditional ova, cysts and parasite microscopy test (OCP-M).ResultsThe Verweij real-time PCR used primers for the (SSU) rRNA gene, and produced a diagnostic sensitivity of 93.4% (95% CI 88.30% to 98.50%) and an efficiency of 100%. Primerdesign's real-time PCR used primers for the glutamate dehydrogenase gene and produced a diagnostic sensitivity of 61.5% (95% CI 51.50% to 71.50%) and an efficiency of 203%. The OCP-M sensitivity was 83.5% (95% CI 75.87% to 91.13%).ConclusionsThe Verweij real-time PCR was robust and the most sensitive assay suited for use as a first-line diagnostic test for giardiasis.

scholarly journals Flavohaemoglobin: the pre-eminent nitric oxide–detoxifying machine of microorganisms

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 7 ◽  
Author(s):  
Robert K. Poole
Keyword(s):  
Nitric Oxide ◽  
The Past ◽  
Nitric Oxide Metabolism ◽  
Nitric Oxide Detoxification ◽  
Bacterial Systems

Flavohaemoglobins were first described in yeast as early as the 1970s but their functions were unclear. The surge in interest in nitric oxide biology and both serendipitous and hypothesis-driven discoveries in bacterial systems have transformed our understanding of this unusual two-domain globin into a comprehensive, yet undoubtedly incomplete, appreciation of its pre-eminent role in nitric oxide detoxification. Here, I focus on research on the flavohaemoglobins of microorganisms, especially of bacteria, and update several earlier and more comprehensive reviews, emphasising advances over the past 5 to 10 years and some controversies that have arisen. Inevitably, in light of space restrictions, details of nitric oxide metabolism and globins in higher organisms are brief.

scholarly journals Serglycin-Deficiency Causes Reduced Weight Gain and Changed Intestinal Cytokine Responses in Mice Infected With Giardia intestinalis

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhiqiang Li ◽  
Dimitra Peirasmaki ◽  
Staffan Svärd ◽  
Magnus Åbrink
Keyword(s):  
Weight Gain ◽  
Immune Responses ◽  
Morphological Changes ◽  
Protozoan Parasite ◽  
Giardia Intestinalis ◽  
Expression Levels ◽  
Non Invasive ◽  
Adaptive Immune Cells ◽  
The Impact ◽  
Deficient Mice

The proteoglycan serglycin (SG) is expressed by different innate and adaptive immune cells, e.g. mast cells, macrophages, neutrophils, and cytotoxic T lymphocytes, where SG contributes to correct granule storage and extracellular activity of inflammatory mediators. Here the serglycin-deficient (SG−/−) mouse strain was used to investigate the impact of SG on intestinal immune responses during infection with the non-invasive protozoan parasite Giardia intestinalis. Young (≈11 weeks old) oral gavage-infected congenic SG−/− mice showed reduced weight gain as compared with the infected SG+/+ littermate mice and the PBS-challenged SG−/− and SG+/+ littermate mice. The infection caused no major morphological changes in the small intestine. However, a SG-independent increased goblet cell and granulocyte cell count was observed, which did not correlate with an increased myeloperoxidase or neutrophil elastase activity. Furthermore, infected mice showed increased serum IL-6 levels, with significantly reduced serum IL-6 levels in infected SG-deficient mice and decreased intestinal expression levels of IL-6 in the infected SG-deficient mice. In infected mice the qPCR analysis of alarmins, chemokines, cytokines, and nitric oxide synthases (NOS), showed that the SG-deficiency caused reduced intestinal expression levels of TNF-α and CXCL2, and increased IFN-γ, CXCL1, and NOS1 levels as compared with SG-competent mice. This study shows that SG plays a regulatory role in intestinal immune responses, reflected by changes in chemokine and cytokine expression levels and a delayed weight gain in young SG−/− mice infected with G. intestinalis.

scholarly journals Horizontal gene transfer in the human and skin commensal Malassezia: a bacterially-derived flavohemoglobin is required for NO resistance and host interaction

2020 ◽  
Author(s):  
Giuseppe Ianiri ◽  
Marco A. Coelho ◽  
Fiorella Ruchti ◽  
Florian Sparber ◽  
Timothy J. McMahon ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pancreatic Cancer ◽  
Crohn’S Disease ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Crohn's Disease ◽  
Stress Resistance ◽  
Nitrosative Stress ◽  
Nitric Oxide Detoxification ◽  
Encoding Genes

AbstractThe skin of humans and animals is colonized by commensal and pathogenic fungi and bacteria that share this ecological niche and have established microbial interactions. Malassezia are the most abundant fungal skin inhabitant of warm-blooded animals, and have been implicated in skin diseases and systemic disorders, including Crohn’s disease and pancreatic cancer. Flavohemoglobin is a key enzyme involved in microbial nitrosative stress resistance and nitric oxide degradation. Comparative genomics and phylogenetic analyses within the Malassezia genus revealed that flavohemoglobin-encoding genes were acquired through independent horizontal gene transfer events from different donor bacteria that are part of the mammalian microbiome. Through targeted gene deletion and functional complementation in M. sympodialis, we demonstrated that bacterially-derived flavohemoglobins are cytoplasmic proteins required for nitric oxide detoxification and nitrosative stress resistance under aerobic conditions. RNAseq analysis revealed that endogenous accumulation of nitric oxide resulted in upregulation of genes involved in stress response, and downregulation of the MalaS7 allergen-encoding genes. Solution of the high-resolution X-ray crystal structure of Malassezia flavohemoglobin revealed features conserved with both bacterial and fungal flavohemoglobins. In vivo pathogenesis is independent of Malassezia flavohemoglobin. Lastly, we identified additional 30 genus- and species-specific horizontal gene transfer candidates that might have contributed to the evolution of this genus as the most common inhabitants of animal skin.Significance statementMalassezia species are the main fungal components of the mammalian skin microbiome and are associated with a number of skin disorders. Recently, Malassezia has also been found in association with Crohn’s Disease and with pancreatic cancer. The elucidation of the molecular bases of skin adaptation by Malassezia is critical to understand its role as commensal and pathogen. In this study we employed evolutionary, molecular, biochemical, and structural analyses to demonstrate that the bacterially-derived flavohemoglobins acquired by Malassezia through horizontal gene transfer resulted in a gain of function critical for nitric oxide detoxification and resistance to nitrosative stress. Our study underscores horizontal gene transfer as an important force modulating Malassezia evolution and niche adaptation.

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