Morphological changes during the life cycle ofAureobasidium pullulans (de Bary) Arnaud

1980 ◽  
Vol 25 (1) ◽  
pp. 56-67 ◽  
Author(s):  
A. Kocková-Kratochvílová ◽  
M. Černáková ◽  
E. Sláviková
Keyword(s):  
Life Cycle ◽  
Morphological Changes

scholarly journals Identification of Fis1 Interactors in Toxoplasma gondii Reveals a Novel Protein Required for Peripheral Distribution of the Mitochondrion

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kylie Jacobs ◽  
Robert Charvat ◽  
Gustavo Arrizabalaga
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Morphological Changes ◽  
Dominant Negative Effect ◽  
Mitochondrial Outer Membrane ◽  
Mitochondrial Morphology ◽  
Content Type ◽  
Membrane Contact Sites ◽  
Intracellular Parasites ◽  
Single Mitochondrion

ABSTRACT Toxoplasma gondii’s single mitochondrion is very dynamic and undergoes morphological changes throughout the parasite’s life cycle. During parasite division, the mitochondrion elongates, enters the daughter cells just prior to cytokinesis, and undergoes fission. Extensive morphological changes also occur as the parasite transitions from the intracellular environment to the extracellular environment. We show that treatment with the ionophore monensin causes reversible constriction of the mitochondrial outer membrane and that this effect depends on the function of the fission-related protein Fis1. We also observed that mislocalization of the endogenous Fis1 causes a dominant-negative effect that affects the morphology of the mitochondrion. As this suggests that Fis1 interacts with proteins critical for maintenance of mitochondrial structure, we performed various protein interaction trap screens. In this manner, we identified a novel outer mitochondrial membrane protein, LMF1, which is essential for positioning of the mitochondrion in intracellular parasites. Normally, while inside a host cell, the parasite mitochondrion is maintained in a lasso shape that stretches around the parasite periphery where it has regions of coupling with the parasite pellicle, suggesting the presence of membrane contact sites. In intracellular parasites lacking LMF1, the mitochondrion is retracted away from the pellicle and instead is collapsed, as normally seen only in extracellular parasites. We show that this phenotype is associated with defects in parasite fitness and mitochondrial segregation. Thus, LMF1 is necessary for mitochondrial association with the parasite pellicle during intracellular growth, and proper mitochondrial morphology is a prerequisite for mitochondrial division. IMPORTANCE Toxoplasma gondii is an opportunistic pathogen that can cause devastating tissue damage in the immunocompromised and congenitally infected. Current therapies are not effective against all life stages of the parasite, and many cause toxic effects. The single mitochondrion of this parasite is a validated drug target, and it changes its shape throughout its life cycle. When the parasite is inside a cell, the mitochondrion adopts a lasso shape that lies in close proximity to the pellicle. The functional significance of this morphology is not understood and the proteins involved are currently not known. We have identified a protein that is required for proper mitochondrial positioning at the periphery and that likely plays a role in tethering this organelle. Loss of this protein results in dramatic changes to the mitochondrial morphology and significant parasite division and propagation defects. Our results give important insight into the molecular mechanisms regulating mitochondrial morphology.

Multi-instar descriptions of cave dwelling Erythraeidae (Trombidiformes: Parasitengona) employing an integrative approach

Zootaxa ◽  
2019 ◽  
Vol 4717 (1) ◽  
pp. 137-184 ◽  
Author(s):  
SAMUEL GEREMIAS DOS SANTOS COSTA ◽  
HANS KLOMPEN ◽  
LEOPOLDO FERREIRA DE OLIVEIRA BERNARDI ◽  
LUCIANA CARDOSO GONÇALVES ◽  
DANTE BATISTA RIBEIRO ◽  
...  
Keyword(s):  
Life Cycle ◽  
Cytochrome Oxidase ◽  
Molecular Analysis ◽  
Species Delimitation ◽  
Morphological Changes ◽  
Molecular Data ◽  
Coi Gene ◽  
Integrative Approach ◽  
Larval Instars ◽  
Individual Host

The life cycle of Parasitengona includes major morphological changes precluding an instar association based only on the morphology. This makes rearing and/or molecular data necessary to associate the heteromorphic instars. Most of the described species are known from either post larval instars or larva. Following a previous study on Palearctic Erythraeidae, in the present study the instar association was made through an integrative approach including rearing trials and molecular analysis of the cytochrome oxidase I (COI) gene with the Bayesian Generalized Mixed Yule Coalescent (bGMYC) algorithm for species delimitation. Two new cave dwelling Erythraeidae (Trombidiformes: Parasitengona) species are described Lasioerythraeus jessicae sp. nov. and Leptus sidorchukae sp. nov. including all active instars. Additionally, a complete description of the previously unknown adults of Charletonia rocciai Treat & Flechtmann, 1979 is provided with notes on the larva and deutonymph. We also demonstrate experimentally that Ch. rocciai larvae are not attached to the same individual host during the entire feeding stage. We discuss the presence of troglomorphisms in Le. sidorchukae sp. nov.; and the distribution of the species. 

scholarly journals The evolution of laminar thermals

2019 ◽  
Vol 878 ◽  
pp. 907-931 ◽  
Author(s):  
J. W. Atkinson ◽  
P. A. Davidson
Keyword(s):  
Life Cycle ◽  
Vortex Ring ◽  
Critical Reynolds Number ◽  
Morphological Changes ◽  
Mathematical Framework ◽  
Initial Condition ◽  
Thermal Transitions ◽  
Left Behind ◽  
Vorticity Flux ◽  
Initial Heat

We consider the life cycle of an axisymmetric laminar thermal starting from the initial condition of a Gaussian buoyant blob. We find that, as time progresses, the thermal transitions through a number of distinct stages, undergoing several morphological changes before ending up as a vortex ring. Whilst each stage is interesting in its own right, one objective of this study is to set out a consistent mathematical framework under which the entire life cycle can be studied. This allows examination of the transition between the different stages, as well as shedding light on some unsolved questions from previous works. We find that the early stages of formation are key in determining the properties of the final buoyant vortex ring and that, since they occur on a time scale where viscosity has little effect, the final properties of the ring display an independence above a critical Reynolds number. We also find that rings consistently contain the same proportion of the initial heat and have a consistent vorticity flux. By considering the effect of Prandtl number, we show that thermal diffusion can have a significant impact on development, smoothing out the temperature field and inhibiting the generation of vorticity. Finally, by considering the wake left behind as well as the vortex ring that is generated, we observe that the wake can itself roll up to form a second mushroom cap and subsequently a secondary vortex ring that follows the first.

scholarly journals In VivoLabelling of Adenovirus DNA Identifies Chromatin Anchoring and Biphasic Genome Replication

2018 ◽  
Vol 92 (18) ◽  
Author(s):  
Tetsuro Komatsu ◽  
Charlotte Quentin-Froignant ◽  
Irene Carlon-Andres ◽  
Floriane Lagadec ◽  
Fabienne Rayne ◽  
...  
Keyword(s):  
Life Cycle ◽  
Real Time ◽  
Viral Genome ◽  
Imaging System ◽  
Morphological Changes ◽  
Host Cells ◽  
Genome Replication ◽  
Equal Distribution ◽  
Viral Genomes

ABSTRACTAdenoviruses are DNA viruses with a lytic infection cycle. Following the fate of incoming as well as recently replicated genomes during infections is a challenge. In this study, we used the ANCHOR3 technology based on a bacterial partitioning system to establish a versatilein vivoimaging system for adenoviral genomes. The system allows the visualization of both individual incoming and newly replicated genomes in real time in living cells. We demonstrate that incoming adenoviral genomes are attached to condensed cellular chromatin during mitosis, facilitating the equal distribution of viral genomes in daughter cells after cell division. We show that the formation of replication centers occurs in conjunction within vivogenome replication and determine replication rates. Visualization of adenoviral DNA revealed that adenoviruses exhibit two kinetically distinct phases of genome replication. Low-level replication occurred during early replication, while high-level replication was associated with late replication phases. The transition between these phases occurred concomitantly with morphological changes of viral replication compartments and with the appearance of virus-induced postreplication (ViPR) bodies, identified by the nucleolar protein Mybbp1A. Taken together, our real-time genome imaging system revealed hitherto uncharacterized features of adenoviral genomesin vivo. The system is able to identify novel spatiotemporal aspects of the adenovirus life cycle and is potentially transferable to other viral systems with a double-stranded DNA phase.IMPORTANCEViruses must deliver their genomes to host cells to ensure replication and propagation. Characterizing the fate of viral genomes is crucial to understand the viral life cycle and the fate of virus-derived vector tools. Here, we integrated the ANCHOR3 system, anin vivoDNA-tagging technology, into the adenoviral genome for real-time genome detection. ANCHOR3 tagging permitted thein vivovisualization of incoming genomes at the onset of infection and of replicated genomes at late phases of infection. Using this system, we show viral genome attachment to condensed host chromosomes during mitosis, identifying this mechanism as a mode of cell-to-cell transfer. We characterize the spatiotemporal organization of adenovirus replication and identify two kinetically distinct phases of viral genome replication. The ANCHOR3 system is the first technique that allows the continuous visualization of adenoviral genomes during the entire virus life cycle, opening the way for further in-depth study.

scholarly journals Biofilms Comprise a Component of the Annual Cycle ofVibrio choleraein the Bay of Bengal Estuary

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. e00483-18 ◽  
Author(s):  
Marzia Sultana ◽  
Suraia Nusrin ◽  
Nur A. Hasan ◽  
Abdus Sadique ◽  
Kabir U. Ahmed ◽  
...  
Keyword(s):  
Life Cycle ◽  
Vibrio Cholerae ◽  
Causative Agent ◽  
Aquatic Environment ◽  
Morphological Changes ◽  
Living Cells ◽  
Estuarine Environment ◽  
Annual Life Cycle ◽  
Free Living ◽  
Content Type

ABSTRACTVibrio cholerae, an estuarine bacterium, is the causative agent of cholera, a severe diarrheal disease that demonstrates seasonal incidence in Bangladesh. In an extensive study ofV. choleraeoccurrence in a natural aquatic environment, water and plankton samples were collected biweekly between December 2005 and November 2006 from Mathbaria, an estuarine village of Bangladesh near the mangrove forests of the Sundarbans. ToxigenicV. choleraeexhibited two seasonal growth peaks, one in spring (March to May) and another in autumn (September to November), corresponding to the two annual seasonal outbreaks of cholera in this region. The total numbers of bacteria determined by heterotrophic plate count (HPC), representing culturable bacteria, accounted for 1% to 2.7% of the total numbers obtained using acridine orange direct counting (AODC). The highest bacterial culture counts, including toxigenicV. cholerae, were recorded in the spring. The direct fluorescent antibody (DFA) assay was used to detectV. choleraeO1 cells throughout the year, as free-living cells, within clusters, or in association with plankton.V. choleraeO1 varied significantly in morphology, appearing as distinctly rod-shaped cells in the spring months, while small coccoid cells within thick clusters of biofilm were observed during interepidemic periods of the year, notably during the winter months. ToxigenicV. choleraeO1 was culturable in natural water during the spring when the temperature rose sharply. The results of this study confirmed biofilms to be a means of persistence for bacteria and an integral component of the annual life cycle of toxigenicV. choleraein the estuarine environment of Bangladesh.IMPORTANCEVibrio cholerae, the causative agent of cholera, is autochthonous in the estuarine aquatic environment. This study describes morphological changes in naturally occurringV. choleraeO1 in the estuarine environment of Mathbaria, where the bacterium is culturable when the water temperature rises and is observable predominantly as distinct rods and dividing cells. In the spring and fall, these morphological changes coincide with the two seasonal peaks of endemic cholera in Bangladesh.V. choleraeO1 cells are predominantly coccoid within biofilms but are rod shaped as free-living cells and when attached to plankton or to particulate matter in interepidemic periods of the year. It is concluded that biofilms represent a stage of the annual life cycle ofV. choleraeO1, the causative agent of cholera in Bangladesh.

Morphological changes in the life cycle of the green alga Haematococcus pluvialis

1997 ◽  
Vol 84 (1) ◽  
pp. 94-97 ◽  
Author(s):  
Makio Kobayashi ◽  
Yoshiro Kurimura ◽  
Toshihide Kakizono ◽  
Naomichi Nishio ◽  
Yasunobu Tsuji
Keyword(s):  
Life Cycle ◽  
Green Alga ◽  
Haematococcus Pluvialis ◽  
Morphological Changes

Cell Adhesion, Multicellular Morphology, and Magnetosome Distribution in the Multicellular Magnetotactic Prokaryote Candidatus Magnetoglobus multicellularis

2013 ◽  
Vol 19 (3) ◽  
pp. 535-543 ◽  
Author(s):  
Fernanda Abreu ◽  
Karen Tavares Silva ◽  
Pedro Leão ◽  
Iame Alves Guedes ◽  
Carolina Neumann Keim ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Life Cycle ◽  
Morphological Changes ◽  
Cellular Interactions ◽  
Proper Position ◽  
Field Orientation ◽  
Magnetic Field Orientation ◽  
A Cell ◽  
Field Lines

AbstractCandidatus Magnetoglobus multicellularis is an uncultured magnetotactic multicellular prokaryote composed of 17-40 Gram-negative cells that are capable of synthesizing organelles known as magnetosomes. The magnetosomes of Ca. M. multicellularis are composed of greigite and are organized in chains that are responsible for the microorganism's orientation along magnetic field lines. The characteristics of the microorganism, including its multicellular life cycle, magnetic field orientation, and swimming behavior, and the lack of viability of individual cells detached from the whole assembly, are considered strong evidence for the existence of a unique multicellular life cycle among prokaryotes. It has been proposed that the position of each cell within the aggregate is fundamental for the maintenance of its distinctive morphology and magnetic field orientation. However, the cellular organization of the whole organism has never been studied in detail. Here, we investigated the magnetosome organization within a cell, its distribution within the microorganism, and the intercellular relationships that might be responsible for maintaining the cells in the proper position within the microorganism, which is essential for determining the magnetic properties of Ca. M. multicellularis during its life cycle. The results indicate that cellular interactions are essential for the determination of individual cell shape and the magnetic properties of the organism and are likely directly associated with the morphological changes that occur during the multicellular life cycle of this species.

scholarly journals LeishIF4E1 Deletion Affects the Promastigote Proteome, Morphology, and Infectivity

mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Nitin Tupperwar ◽  
Rohit Shrivastava ◽  
Michal Shapira
Keyword(s):  
Gene Expression ◽  
Life Cycle ◽  
Expression Profile ◽  
Morphological Changes ◽  
Binding Activity ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Sand Fly ◽  
Null Mutant ◽  
Sand Fly Vectors

ABSTRACT Leishmania parasites cycle between sand-fly vectors and mammalian hosts, adapting to changing environmental conditions by driving a stage-specific program of gene expression, which is tightly regulated by translation processes. Leishmania encodes six eIF4E orthologs (LeishIF4Es) and five eIF4G candidates, forming different cap-binding complexes with potentially varying functions. Most LeishIF4E paralogs display temperature sensitivity in their cap-binding activity, except for LeishIF4E1, which maintains its cap-binding activity under all conditions. We used the CRISPR-Cas9 system to successfully generate a null mutant of LeishIF4E1 and examine how its elimination affected parasite physiology. Although the LeishIF4E1–/– null mutant was viable, its growth was impaired, in line with a reduction in global translation. As a result of the mutation, the null LeishIF4E1–/– mutant had a defective morphology, as the cells were round and unable to grow a normal flagellum. This was further emphasized when the LeishIF4E1–/– cells failed to develop the promastigote morphology once they shifted from conditions that generate axenic amastigotes (33°C, pH 5.5) back to neutral pH and 25°C, and they maintained their short flagellum and circular structure. Finally, the LeishIF4E1–/– null mutant displayed difficulty in infecting cultured macrophages. The morphological changes and reduced infectivity of the mutant may be related to differences in the proteomic profile of LeishIF4E1–/– cells from that of controls. All defects monitored in the LeishIF4E1–/– null mutant were reversed in the add-back strain, in which expression of LeishIF4E1 was reconstituted, establishing a strong link between the cellular defects and the absence of LeishIF4E1 expression. IMPORTANCE Leishmania parasites are the causative agents of a broad spectrum of diseases. The parasites migrate between sand-fly vectors and mammalian hosts, adapting to changing environments by driving a regulated program of gene expression, with translation regulation playing a key role. The leishmanias encode six different paralogs of eIF4E, the cap-binding translation initiation factor. Since these vary in function, expression profile, and assemblage, it is assumed that each is assigned a specific role throughout the life cycle. Using the CRISPR-Cas9 system for Leishmania, we generated a null mutant of LeishIF4E1, eliminating both alleles. Although the mutant cells were viable, their morphology was altered and their ability to synthesize the flagellum was impaired. Elimination of LeishIF4E1 affected their protein expression profile and decreased their ability to infect cultured macrophages. Restoring LeishIF4E1 expression restored the affected features. This study highlights the importance of LeishIF4E1 in diverse cellular events during the life cycle of Leishmania.

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