A freeze-fracture study of microsporidia (Protozoa: Microspora)

Vinckier, D.; Porchet, Eliane; Vivier, Emile; Vávra, Jiří; Torpier, Gérard

doi:10.1016/s0932-4739(11)80399-8

Cited by 8 publications

(7 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The polaroplast is a system of membrane-limited cavities in the anterior part of the spore [11,17,44,45]. The expansion of polaroplast results in the disturbed was not certified by peer review) is the author/funder.…”

Section: Discussionmentioning

confidence: 99%

“…Mature spores have a unique infection apparatus for invasion, which includes the polar filament (defined as the polar tube after spore germination), polaroplast and posterior vacuole (PV) [11,15,16]. In all microsporidian mature spores [11,17], the polar filament tightly coils and forms a spring-like structure [18], which is a solid structure comprising electron-dense alternating concentric rings in cross-sections [6,19]. In 2022, the macrostructure of the polar filament in Encephalitozoon hellem was characterized by Cryo-EM and demonstrated that the polar filament had a multi-layer concentric circle structure and many bumps with a diameter of 2.5 nm were present on the second layer of polar filament [20].…”

Section: Introductionmentioning

confidence: 99%

“…In 2022, the macrostructure of the polar filament in Encephalitozoon hellem was characterized by Cryo-EM and demonstrated that the polar filament had a multi-layer concentric circle structure and many bumps with a diameter of 2.5 nm were present on the second layer of polar filament [20]. The polaroplast is a system of membrane-limited cavities in the anterior part of the spore, which occupies one-third to one-half of the spore volume [11,17]. The compartments of the polaroplast are shaped like lamellae, chambers, or tubules delimited by approximately 5 nm thick unit membranes [11,21].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Chen

et al. 2023

Preprint

View full text Add to dashboard Cite

Microsporidia are obligate intracellular parasites that infect a wide variety of hosts, including humans. Microsporidian spores possess a unique, highly specialized invasion apparatus involving the polar filament, polaroplast and posterior vacuole. During spore germination, the polar filament is discharged out of the spore forming the hollow polar tube that transports the sporoplasm components including nucleus into the host cell to achieve the invasion. Due to the complicated topological changes occurring in this process, the formation of sporoplasm is unclear. Here, electron microscopy observation and DiI staining confirmed that during spore germination, a large number of vesicles derived from the polaroplast, nucleus and other cytoplasm were transported out via the polar tube. Meanwhile, the posterior vacuole and plasma membrane remained in the empty spore coat. In addition, there was no DiI-labeled membrane around the nucleus in mature spores, whereas a DiI-labeled limit membrane wrapping nucleus was found at the tip of the extruded polar tube, suggesting that the membrane of sporoplasm was formed outside the mature spore. TwoNosema bombycissporoplasm surface proteins (NbTMP1 and NoboABCG1.1) were located at the polaroplast in mature spores, in the extruded polar tube and on the sporoplasm membrane, which indicated that the polaroplast transported via the polar tube finally became the limiting membrane of the sporoplasm. Golgi-tracker green and Golgi marker protein syntaxin 6 were also found the same model, which was consistent with the transported polaroplast derived from Golgi transformed into the novel sporoplasm membrane during spore germination.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Chen

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Mature spores have a unique infection apparatus for invasion, which includes the polar filament (also defined as the polar tube after spore germination), polaroplast, and posterior vacuole (PV) ( 11 , 15 , 16 ). In mature spores, the polar filament is tightly coiled and forms a spring-like structure ( 11 , 17 , 18 ), which is a solid structure comprising electron-dense alternating concentric rings in cross-sections ( 6 , 19 ). In 2022, the macrostructure of the polar filament in Encephalitozoon hellem was characterized by cryogenic electron microscopy (Cryo-EM) and demonstrated that the polar filament had a multi-layer concentric circle structure and that many bumps with a diameter of 2.5 nm were present on the second layer of polar filament ( 20 ).…”

Section: Introductionmentioning

confidence: 99%

“…In 2022, the macrostructure of the polar filament in Encephalitozoon hellem was characterized by cryogenic electron microscopy (Cryo-EM) and demonstrated that the polar filament had a multi-layer concentric circle structure and that many bumps with a diameter of 2.5 nm were present on the second layer of polar filament ( 20 ). The polaroplast is a system of membrane-limited cavities in the anterior part of the spore, which occupies one-third to one-half volume of the mature spore ( 11 , 17 ). The compartments of the polaroplast are shaped like lamellae, chambers, or tubules delimited by approximately 5-nm-thick unit membranes ( 11 , 21 ).…”

Section: Introductionmentioning

confidence: 99%

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Lv,

Hong,

et al. 2024

mBio

View full text Add to dashboard Cite

Microsporidia are obligate intracellular parasites that infect a wide variety of hosts including humans. Microsporidian spores possess a unique, highly specialized invasion apparatus involving the polar filament, polaroplast, and posterior vacuole. During spore germination, the polar filament is discharged out of the spore forming a hollow polar tube that transports the sporoplasm components including the nucleus into the host cell. Due to the complicated topological changes occurring in this process, the details of sporoplasm formation are not clear. Our data suggest that the limiting membrane of the nascent sporoplasm is formed by the polaroplast after microsporidian germination. Using electron microscopy and 1,1′-dioctadecyl-3,3,3′,3′ tetramethyl indocarbocyanine perchlorate staining, we describe that a large number of vesicles, nucleus, and other cytoplasm contents were transported out via the polar tube during spore germination, while the posterior vacuole and plasma membrane finally remained in the empty spore coat. Two Nosema bombycis sporoplasm surface proteins (NbTMP1 and NoboABCG1.1) were also found to localize in the region of the polaroplast and posterior vacuole in mature spores and in the discharged polar tube, which suggested that the polaroplast during transport through the polar tube became the limiting membrane of the sporoplasm. The analysis results of Golgi-tracker green and Golgi marker protein syntaxin 6 were also consistent with the model of the transported polaroplast derived from Golgi transformed into the nascent sporoplasm membrane. IMPORTANCE Microsporidia, which are obligate intracellular pathogenic organisms, cause huge economic losses in agriculture and even threaten human health. The key to successful infection by the microsporidia is their unique invasion apparatus which includes the polar filament, polaroplast, and posterior vacuole. When the mature spore is activated to geminate, the polar filament uncoils and undergoes a rapid transition into the hollow polar tube that transports the sporoplasm components including the microsporidian nucleus into host cells. Details of the structural difference between the polar filament and polar tube, the process of cargo transport in extruded polar tube, and the formation of the sporoplasm membrane are still poorly understood. Herein, we verify that the polar filament evaginates to form the polar tube, which serves as a conduit for transporting the nucleus and other sporoplasm components. Furthermore, our results indicate that the transported polaroplast transforms into the sporoplasm membrane during spore germination. Our study provides new insights into the cargo transportation process of the polar tube and origin of the sporoplasm membrane, which provide important clarification of the microsporidian infection mechanism.

show abstract

Structure of Microsporidia

Vávra

Larsson

2014

Microsporidia

View full text Add to dashboard Cite

A freeze-fracture study of microsporidia (Protozoa: Microspora)

Cited by 8 publications

References 9 publications

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Structure of Microsporidia

Contact Info

Product

Resources

About