scholarly journals Expression and Physiological Role of Three Myxococcus xanthus Copper-Dependent P1B-Type ATPases during Bacterial Growth and Development

2010 ◽  
Vol 76 (18) ◽  
pp. 6077-6084 ◽  
Author(s):  
Aurelio Moraleda-Muñoz ◽  
Juana Pérez ◽  
Antonio Luis Extremera ◽  
José Muñoz-Dorado
Keyword(s):  
Life Cycle ◽  
Expression Profiles ◽  
Myxococcus Xanthus ◽  
Physiological Role ◽  
Copper Homeostasis ◽  
Cellular Damage ◽  
Complex Life Cycle ◽  
Sequence Motifs ◽  
Dual Effect

ABSTRACT Myxococcus xanthus is a soil-dwelling bacterium that exhibits a complex life cycle comprising social behavior, morphogenesis, and differentiation. In order to successfully complete this life cycle, cells have to cope with changes in their environment, among which the presence of copper is remarkable. Copper is an essential transition metal for life, but an excess of copper provokes cellular damage by oxidative stress. This dual effect forces the cells to maintain a tight homeostasis. M. xanthus encodes a large number of genes with similarities to others reported previously to be involved in copper homeostasis, most of which are redundant. We have identified three genes that encode copper-translocating P1B-ATPases (designated copA, copB, and copC) that exhibit the sequence motifs and modular organizations of those that extrude Cu+. The expression of the ATPase copC has not been detected, but copA and copB are differentially regulated by the addition of external copper. However, while copB expression peaks at 2 h, copA is expressed at higher levels, and the maximum is reached much later. The fact that these expression profiles are nearly identical to those exhibited by the multicopper oxidases cuoA and cuoB suggests that the pairs CuoB-CopB and CuoA-CopA sequentially function to detoxify the cell. The deletion of any ATPase alters the expression profiles of other genes involved in copper homeostasis, such as the remaining ATPases or the Cus systems, yielding cells that are more resistant to the metal.

scholarly journals Role of two metacaspases in development and pathogenicity of the Rice Blast fungus, Magnaporthe oryzae

2020 ◽  
Author(s):  
Jessie Fernandez ◽  
Victor Lopez ◽  
Lisa Kinch ◽  
Mariel A. Pfeifer ◽  
Hillery Gray ◽  
...  
Keyword(s):  
Cell Death ◽  
Food Security ◽  
Life Cycle ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Disease ◽  
Blast Disease ◽  
Complex Life Cycle ◽  
Insight Into

ABSTRACTRice blast disease caused by Magnaporthe oryzae is a devastating disease of cultivated rice worldwide. Infections by this fungus lead to a significant reduction in rice yields and threats to food security. To gain better insight into growth and cell death in M. oryzae during infection, we characterized two predicted M. oryzae metacaspase proteins, MoMca1 and MoMca2. These proteins appear to be functionally redundant and are able to complement the yeast Yca1 homologue. Biochemical analysis revealed that M. oryzae metacaspases exhibited Ca2+ dependent caspase activity in vitro. Deletion of both MoMca1 and MoMca2 in M. oryzae resulted in reduced sporulation, delay in conidial germination and attenuation of disease severity. In addition, the double ΔMomca1mca2 mutant strain showed increased radial growth in the presence of oxidative stress. Interestingly, the ΔMomca1mca2 strain showed an increase accumulation of insoluble aggregates compared to the wild-type strain during vegetative growth. Our findings suggest that MoMca1 and MoMca2 promote the clearance of insoluble aggregates in M. oryzae, demonstrating the important role these metacaspases have in fungal protein homeostasis. Furthermore, these metacaspase proteins may play additional roles, like in regulating stress responses, that would help maintain the fitness of fungal cells required for host infection.IMPORTANCEMagnaporthe oryzae causes rice blast disease that threatens global food security by resulting in the severe loss of rice production every year. A tightly regulated life cycle allows M. oryzae to disarm the host plant immune system during its biotrophic stage before triggering plant cell death in its necrotrophic stage. The ways M. oryzae navigates its complex life cycle remains unclear. This work characterizes two metacaspase proteins with peptidase activity in M. oryzae that are shown to be involved in the regulation of fungal growth and development prior to infection by potentially helping maintain fungal fitness. This study provides new insight into the role of metacaspase proteins in filamentous fungi by illustrating the delays in M. oryzae morphogenesis in the absence of these proteins. Understanding the mechanisms by which M. oryzae morphology and development promote its devastating pathogenicity may lead to the emergence of proper methods for disease control.

scholarly journals Metamorphoses of malaria: the role of autophagy in parasite differentiation

2011 ◽  
Vol 51 ◽  
pp. 127-136 ◽  
Author(s):  
Isabelle Coppens
Keyword(s):  
Life Cycle ◽  
Complex Life Cycle ◽  
Mammalian Host ◽  
Protozoan Parasites ◽  
Membrane Complex ◽  
Autophagic Process ◽  
Inner Membrane Complex ◽  
Form Development ◽  
High Degree

Several protozoan parasites undergo a complex life cycle that alternates between an invertebrate vector and a vertebrate host. Adaptations to these different environments by the parasites are achieved by drastic changes in their morphology and metabolism. The malaria parasites must be transmitted to a mammal from a mosquito as part of their life cycle. Upon entering the mammalian host, extracellular malaria sporozoites reach the liver and invade hepatocytes, wherein they meet the challenge of becoming replication-competent schizonts. During the process of conversion, the sporozoite selectively discards organelles that are unnecessary for the parasite growth in liver cells. Among the organelles that are cleared from the sporozoite are the micronemes, abundant secretory vesicles that facilitate the adhesion of the parasite to hepatocytes. Organelles specialized in sporozoite motility and structure, such as the inner membrane complex (a major component of the motile parasite's cytoskeleton), are also eliminated from converting parasites. The high degree of sophistication of the metamorphosis that occurs at the onset of the liver-form development cascade suggests that the observed changes must be multifactorial. Among the mechanisms implicated in the elimination of sporozoite organelles, the degradative process called autophagy contributes to the remodelling of the parasite interior and the production of replicative liver forms. In a broader context, the importance of the role played by autophagy during the differentiation of protozoan parasites that cycle between insects and vertebrates is nowadays clearly emerging. An exciting prospect derived from these observations is that the parasite proteins involved in the autophagic process may represent new targets for drug development.

scholarly journals Physiological role of prion protein in copper homeostasis and angiogenic mechanisms of endothelial cells

2019 ◽  
Vol 305 ◽  
pp. S26
Author(s):  
F. Rizzo ◽  
L. De Riccardis ◽  
V. Garzarelli ◽  
C. Intini ◽  
M. Greco ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Prion Protein ◽  
Physiological Role ◽  
Copper Homeostasis

scholarly journals Hurricane Juan (2003). Part I: A Diagnostic and Compositing Life Cycle Study

2006 ◽  
Vol 134 (7) ◽  
pp. 1725-1747 ◽  
Author(s):  
Ron McTaggart-Cowan ◽  
Eyad H. Atallah ◽  
John R. Gyakum ◽  
Lance F. Bosart
Keyword(s):  
Life Cycle ◽  
East Coast ◽  
Leading Edge ◽  
High Amplitude ◽  
Complex Life Cycle ◽  
Low Latitude ◽  
Initial Development ◽  
Easterly Wave ◽  
Case Diagnosis

Abstract A detailed analysis of the complex life cycle of Hurricane Juan (in 2003) is undertaken to elucidate the structures and forcings that prevailed over the period leading up to the hurricane’s landfall in Halifax, Nova Scotia, Canada. Despite the presence of easterly wave precursors, Hurricane Juan’s initial development is shown to occur in a baroclinic environment beneath a low-latitude potential vorticity streamer. This feature interacts with a lower-level shear line as the incipient vortex begins to effectively focus ascent and convection. The system undergoes a slow tropical transition over a period of several days as the deep-layer shear over the developing storm decreases. The hurricane is repeatedly perturbed by subsynoptic-scale waves traveling along the leading edge of a large upstream trough. However, Hurricane Juan maintains its tropical structure despite its relatively high formation latitude (28°N) and its northward trajectory. The unusual persistence of the storm’s tropical nature as it propagates northward is of primary interest in this study. In particular, the role of persistent ridging along the east coast of North America is investigated both in high-resolution analyses for Hurricane Juan and in a compositing framework. Dynamic tropopause, quasigeostrophic, and modified Eady model diagnostics are used to elucidate the interactions between Hurricane Juan and this amplified midlatitude flow. Given the strength and persistence of the anomalous ridge–trough couplet both in the case diagnosis and in the composite fields, the study concludes that the presence of prestorm, high-amplitude ridging along the east coast likely reinforced by diabatic ridging downshear of the storm itself produces an environment both dynamically and thermodynamically conducive to the high-latitude landfall of hurricanes still in the tropical phase.

scholarly journals Circadian Clock and OxInflammation: Functional Crosstalk in Cutaneous Homeostasis

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Elena Frigato ◽  
Mascia Benedusi ◽  
Anna Guiotto ◽  
Cristiano Bertolucci ◽  
Giuseppe Valacchi
Keyword(s):  
Circadian Clock ◽  
Redox Homeostasis ◽  
Physiological Role ◽  
Protective Role ◽  
Circadian System ◽  
Circadian Disruption ◽  
Cellular Damage ◽  
Lifestyle Risk Factors

Circadian rhythms are biological oscillations that occur with an approximately 24 h period and optimize cellular homeostasis and responses to environmental stimuli. A growing collection of data suggests that chronic circadian disruption caused by novel lifestyle risk factors such as shift work, travel across time zones, or irregular sleep-wake cycles has long-term consequences for human health. Among the multiplicity of physiological systems hypothesized to have a role in the onset of pathologies in case of circadian disruption, there are redox-sensitive defensive pathways and inflammatory machinery. Due to its location and barrier physiological role, the skin is a prototypical tissue to study the influence of environmental insults induced OxInflammation disturbance and circadian system alteration. To better investigate the link among outdoor stressors, OxInflammation, and circadian system, we tested the differential responses of keratinocytes clock synchronized or desynchronized, in an in vitro inflammatory model exposed to O3. Being both NRF2 and NF-κB two key redox-sensitive transcription factors involved in cellular redox homeostasis and inflammation, we analyzed their activation and expression in challenged keratinocytes by O3. Our results suggest that a synchronized circadian clock not only facilitates the protective role of NRF2 in terms of a faster and more efficient defensive response against environmental insults but also moderates the cellular damage resulting from a condition of chronic inflammation. Our results bring new insights on the role of circadian clock in regulating the redox-inflammatory crosstalk influenced by O3 and possibly can be extrapolated to other pollutants able to affect the oxinflammatory cellular processes.

scholarly journals Role of Two Metacaspases in Development and Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jessie Fernandez ◽  
Victor Lopez ◽  
Lisa Kinch ◽  
Mariel A. Pfeifer ◽  
Hillery Gray ◽  
...  
Keyword(s):  
Cell Death ◽  
Food Security ◽  
Life Cycle ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Disease ◽  
Blast Disease ◽  
Complex Life Cycle ◽  
Content Type

ABSTRACT Rice blast disease caused by Magnaporthe oryzae is a devastating disease of cultivated rice worldwide. Infections by this fungus lead to a significant reduction in rice yields and threats to food security. To gain better insight into growth and cell death in M. oryzae during infection, we characterized two predicted M. oryzae metacaspase proteins, MoMca1 and MoMca2. These proteins appear to be functionally redundant and can complement the yeast Yca1 homologue. Biochemical analysis revealed that M. oryzae metacaspases exhibited Ca2+-dependent caspase activity in vitro. Deletion of both MoMca1 and MoMca2 in M. oryzae resulted in reduced sporulation, delay in conidial germination, and attenuation of disease severity. In addition, the double ΔMomca1mca2 mutant strain showed increased radial growth in the presence of oxidative stress. Interestingly, the ΔMomca1mca2 strain showed an increased accumulation of insoluble aggregates compared to the wild-type strain during vegetative growth. Our findings suggest that MoMca1 and MoMca2 promote the clearance of insoluble aggregates in M. oryzae, demonstrating the important role these metacaspases have in fungal protein homeostasis. Furthermore, these metacaspase proteins may play additional roles, like in regulating stress responses, that would help maintain the fitness of fungal cells required for host infection. IMPORTANCE Magnaporthe oryzae causes rice blast disease that threatens global food security by resulting in the severe loss of rice production every year. A tightly regulated life cycle allows M. oryzae to disarm the host plant immune system during its biotrophic stage before triggering plant cell death in its necrotrophic stage. The ways M. oryzae navigates its complex life cycle remain unclear. This work characterizes two metacaspase proteins with peptidase activity in M. oryzae that are shown to be involved in the regulation of fungal growth and development prior to infection by potentially helping maintain fungal fitness. This study provides new insights into the role of metacaspase proteins in filamentous fungi by illustrating the delays in M. oryzae morphogenesis in the absence of these proteins. Understanding the mechanisms by which M. oryzae morphology and development promote its devastating pathogenicity may lead to the emergence of proper methods for disease control.

scholarly journals Myxococcus xanthus Displays Frz-Dependent Chemokinetic Behavior during Vegetative Swarming

1998 ◽  
Vol 180 (2) ◽  
pp. 440-443 ◽  
Author(s):  
Mandy J. Ward ◽  
Kenny C. Mok ◽  
David R. Zusman
Keyword(s):  
Signal Transduction ◽  
Life Cycle ◽  
Cell Density ◽  
Myxococcus Xanthus ◽  
Microscopic Analysis ◽  
Time Lapse ◽  
Complex Life Cycle ◽  
Signal Transduction System ◽  
Nutrient Levels ◽  
Time Lapse Video

ABSTRACT Myxococcus xanthus has been shown to utilize both directed (tactic) and undirected (kinetic) movements during different stages of its complex life cycle. We have used time-lapse video microscopic analysis to separate tactic and kinetic behaviors associated specifically with vegetatively swarming cells. Isolated individual cells separated by a thin agar barrier from mature swarms showed significant increases in gliding velocity compared to that of similar cells some distance from the swarm. This orthokinetic behavior was independent of the frequency of reversals of gliding direction (klinokinesis) but did require both the Frz signal transduction system and S-motility. We propose that M. xanthus uses Frz-dependent, auto-orthokinetic behavior to facilitate the dispersal of cells under conditions where both cell density and nutrient levels are high.

scholarly journals Glutamine Analogues Impair Cell Proliferation, the Intracellular Cycle and Metacyclogenesis in Trypanosoma cruzi

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1628
Author(s):  
Rodolpho Ornitz Oliveira Souza ◽  
Marcell Crispim ◽  
Ariel Mariano Silber ◽  
Flávia Silva Damasceno
Keyword(s):  
Cell Proliferation ◽  
Life Cycle ◽  
Trypanosoma Cruzi ◽  
Host Cells ◽  
Glutamine Metabolism ◽  
Complex Life Cycle ◽  
Mammalian Host ◽  
Developmental Cycle ◽  
Parasite Life Cycle

Trypanosoma cruzi is the aetiologic agent of Chagas disease, which affects people in the Americas and worldwide. The parasite has a complex life cycle that alternates among mammalian hosts and insect vectors. During its life cycle, T. cruzi passes through different environments and faces nutrient shortages. It has been established that amino acids, such as proline, histidine, alanine, and glutamate, are crucial to T. cruzi survival. Recently, we described that T. cruzi can biosynthesize glutamine from glutamate and/or obtain it from the extracellular environment, and the role of glutamine in energetic metabolism and metacyclogenesis was demonstrated. In this study, we analysed the effect of glutamine analogues on the parasite life cycle. Here, we show that glutamine analogues impair cell proliferation, the developmental cycle during the infection of mammalian host cells and metacyclogenesis. Taken together, these results show that glutamine is an important metabolite for T. cruzi survival and suggest that glutamine analogues can be used as scaffolds for the development of new trypanocidal drugs. These data also reinforce the supposition that glutamine metabolism is an unexplored possible therapeutic target.

scholarly journals Functional Diversity of the Schistosoma mansoni Tyrosine Kinases

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Lívia G. A. Avelar ◽  
Laila A. Nahum ◽  
Luiza F. Andrade ◽  
Guilherme Oliveira
Keyword(s):  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Tyrosine Kinases ◽  
Large Body ◽  
Protein Domain ◽  
Complex Life Cycle ◽  
Main Process ◽  
Parasite Life Cycle ◽  
Causative Agents

Schistosoma mansoni, one of the causative agents of schistosomiasis, has a complex life cycle infecting over 200 million people worldwide. Such a successful and prolific parasite life cycle has been shown to be dependent on the adaptive interaction between the parasite and hosts. Tyrosine kinases (TKs) play a key role in signaling pathways as demonstrated by a large body of experimental work in eukaryotes. Furthermore, comparative genomics have allowed the identification of TK homologs and provided insights into the functional role of TKs in several biological systems. Finally, TK structural biology has provided a rational basis for obtaining selective inhibitors directed to the treatment of human diseases. This paper covers the important aspects of the phospho-tyrosine signaling network in S. mansoni, Caenorhabditis elegans, and humans, the main process of functional diversification of TKs, that is, protein-domain shuffling, and also discusses TKs as targets for the development of new anti-schistosome drugs.

scholarly journals Neutral and Phospholipids of the Myxococcus xanthus Lipodome during Fruiting Body Formation and Germination

2015 ◽  
Vol 81 (19) ◽  
pp. 6538-6547 ◽  
Author(s):  
Tilman Ahrendt ◽  
Hendrik Wolff ◽  
Helge B. Bode
Keyword(s):  
Life Cycle ◽  
Lipid Profile ◽  
De Novo ◽  
Membrane Lipids ◽  
Myxococcus Xanthus ◽  
Model Organism ◽  
Ether Lipid ◽  
Complex Life Cycle ◽  
Fruiting Body Formation ◽  
Content Type

ABSTRACTMyxobacteria are well-known for their complex life cycle, including the formation of spore-filled fruiting bodies. The model organismMyxococcus xanthusexhibits a highly complex composition of neutral and phospholipids, including triacylglycerols (TAGs), diacylglycerols (DAGs), phosphatidylethanolamines (PEs), phosphatidylglycerols (PGs), cardiolipins (CLs), and sphingolipids, including ceramides (Cers) and ceramide phosphoinositols (Cer-PIs). In addition, ether lipids have been shown to be involved in development and signaling. In this work, we describe the lipid profile ofM. xanthusduring its entire life cycle, including spore germination. PEs, representing one of the major components of the bacterial membrane, decreased by about 85% during development from vegetative rods to round myxospores, while TAGs first accumulated up to 2-fold before they declined 48 h after the induction of sporulation. Presumably, membrane lipids are incorporated into TAG-containing lipid bodies, serving as an intermediary energy source for myxospore formation. The ceramides Cer(d-19:0/iso-17:0) and Cer(d-19:0/16:0) accumulated 6-fold and 3-fold, respectively, after 24 h of development, identifying them to be novel putative biomarkers forM. xanthussporulation. The most abundant ether lipid, 1-iso-15:0-alkyl-2,3-di-iso-15:0-acyl glycerol (TG1), exhibited a lipid profile different from that of all TAGs during sporulation, reinforcing its signaling character. The absence of all these lipid profile changes in mutants during development supports the importance of lipids in myxobacterial development. During germination of myxospores, only thede novobiosynthesis of new cell membrane fatty acids was observed. The unexpected accumulation of TAGs also during germination might indicate a function of TAGs as intermediary storage lipids during this part of the life cycle as well.

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