Since apicomplexans represent exclusively parasitic unicellular organisms with medical and economic impacts, the principles of their motility have been studied intensively. By contrast, the movement in apicomplexan basal groups, such as gregarines, remains to be elucidated. The present study focuses on Gregarina garnhami parasitising the digestive tract of the locust Schistocerca gregaria, and investigates the involvement of cytoskeletal elements (the ectoplasmic network and myonemes) and the secretion of mucosubstances during eugregarine gliding motility. Combined microscopic analyses were used to verify the role of actin filaments and membranes' organisation in G. garnhami motility. A freeze-etching analysis of membranes revealed the size, density, and arrangement of intramembranous particles along with the distribution and size of pores and ducts. Experimental assays using actin-modifying drugs (jasplakinolide, cytochalasin D) confirmed that actin most likely plays a role in cell motility, principally in its filamentous form (=F-actin). Myonemes, localised in the border between the ectoplasm and endoplasm, correspond to the concentric bundles of F-actin. Microscopic analyses confirmed that changes in gamonts motility corresponding to the changes in the organisation and density of myonemes and the ectoplasmic network in drug-treated cells, suggesting that these structures might serve as contractile elements facilitating gliding motility in G. garnhami.
- Klíčová slova
- Ectoplasmic network, F-actin, Gregarine, Motility, Myonemes, Ultrastructure,
- MeSH
- aktiny metabolismus MeSH
- Apicomplexa účinky léků MeSH
- cytochalasin D farmakologie MeSH
- depsipeptidy farmakologie MeSH
- inhibitory syntézy nukleových kyselin farmakologie MeSH
- insekticidy farmakologie MeSH
- pohyb účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aktiny MeSH
- cytochalasin D MeSH
- depsipeptidy MeSH
- inhibitory syntézy nukleových kyselin MeSH
- insekticidy MeSH
- jasplakinolide MeSH Prohlížeč
The role of the actin cytoskeleton in somatic embryo development was investigated using latrunculin B and cytochalasin D. Brief treatments (1h) with either drug at the start of maturation fragmented the actin in suspensor cells and/or depolymerized actin filaments in meristematic cells. The drugs targeted different cells: latB primarily affected the suspensor cells, but cchD damaged both suspensor and meristematic cells. Lethal damage to the meristematic and suspensor cells was observed when the drugs were applied throughout the maturation period, although the severity of this effect depended on their concentrations. The drugs' effects on the yield of mature somatic embryos were investigated by applying them to embryo cultures throughout the maturation period or for one week at three different points in the maturation process: immediately prior to the start of maturation, during the first week of maturation, and during the fourth week of maturation. The strongest effects were observed when the drugs were applied at the start of maturation. Under these conditions, latB destroyed the suspensors, eliminating the underdeveloped embryos that depend on them. This accelerated the development of embryos that were capable of separating from the suspensors. Thus, while the total number of embryos at the end of the maturation period was lower than in untreated control cultures, the surviving mature embryos were of high quality. cchD treatment at the start of maturation strongly inhibited embryo development. Drug treatment at the end of the maturation period did not significantly affect embryo development: latB caused no change in the yield of somatic embryos, but cchD treatment increased the number of malformed embryos compared to untreated controls.
- Klíčová slova
- Actin, Cytoskeleton, Picea abies, Somatic embryogenesis,
- MeSH
- aktiny antagonisté a inhibitory metabolismus MeSH
- bicyklické sloučeniny heterocyklické farmakologie MeSH
- cytochalasin D farmakologie MeSH
- inhibitory syntézy nukleových kyselin aplikace a dávkování farmakologie MeSH
- konfokální mikroskopie MeSH
- semena rostlinná účinky léků embryologie MeSH
- smrk účinky léků embryologie MeSH
- somatická embryogeneze rostlin * MeSH
- thiazolidiny farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aktiny MeSH
- bicyklické sloučeniny heterocyklické MeSH
- cytochalasin D MeSH
- inhibitory syntézy nukleových kyselin MeSH
- latrunculin B MeSH Prohlížeč
- thiazolidiny MeSH
This work is focused on the function of the microtubule and actin networks in plasmid DNA transport during liposomal transfection. We observed strong binding of plasmid DNA-lipid complexes (lipoplexes) to both networks and directional long-range motion of these lipoplexes along the microtubules. Disruption of either of these networks led to the cessation of plasmid transport to the nucleus, a decreased mobility of plasmids, and accumulation of plasmid DNA in large aggregates at the cell periphery. Our findings show an indispensable but different role of both types of cytoskeleton, actin and microtubular, in the processes of gene delivery.
- MeSH
- aktiny metabolismus fyziologie MeSH
- bicyklické sloučeniny heterocyklické farmakologie MeSH
- biologický transport účinky léků MeSH
- cytochalasin D farmakologie MeSH
- DNA genetika metabolismus MeSH
- fibroblasty cytologie účinky léků metabolismus MeSH
- imunoblotting MeSH
- kultivované buňky MeSH
- lidé MeSH
- mikrotubuly metabolismus fyziologie MeSH
- plazmidy genetika metabolismus MeSH
- rekombinantní fúzní proteiny genetika metabolismus MeSH
- thiazolidiny farmakologie MeSH
- transfekce MeSH
- vazba proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aktiny MeSH
- bicyklické sloučeniny heterocyklické MeSH
- cytochalasin D MeSH
- DNA MeSH
- latrunculin B MeSH Prohlížeč
- rekombinantní fúzní proteiny MeSH
- thiazolidiny MeSH
Both living and fixed cells of Schizosaccharomyces japonicus var. versatilis showed thread-like mitochondria when studied by phase-contrast and fluorescence microscopy. In the interphase cells, mitochondria extended from pole to pole and converged towards the growing tips. The mitochondrial threads did not disrupt but persisted during mitosis and, subsequently, their bundle was split between the two daughter cells by a concentrically growing septum. Mitochondria in the interphase cells were accompanied by cytoplasmic microtubules. These disappeared during mitosis and, instead, spindle microtubules were formed in the nucleus. The cytoplasmic microtubules reappeared after anaphase B, again in coaligment with mitochondria. Protoplasting as well as the action of microtubule inhibitors methyl-1-(butylcarbamoyl)-2-benzimidazolecarbamate (benomyl) and 2-methylbenzimidazole (MBC) resulted in rapid disintegration of microtubules and, suprisingly, also in disruption of mitochondria into small bodies. Removal of the inhibitors or a short regeneration of protoplasts allowed both the cytoplasmic microtubules and the thread-like mitochondria to reaggregate into the original pattern. Cytochalasin D treatment caused a complete disintegration of actin filaments, while the cytoplasmic microtubules and mitochondria remained intact. These findings of a transient close association of mitochondria and microtubules and their relative independence of the arrangement of actin filaments suggest that microtubules, but not actin cables, form supports for positioning or movement of mitochondria along the cylindrical cells. The persistence of mitochondria in the cell centre during mitosis may be accounted for by the fact that disrupted microtubules fail to provide support for mitochondrial movement towards the cell poles.
- MeSH
- benomyl farmakologie MeSH
- benzimidazoly farmakologie MeSH
- buněčný cyklus MeSH
- cytochalasin D farmakologie MeSH
- cytoplazma ultrastruktura MeSH
- kompartmentace buňky MeSH
- mikrotubuly účinky léků ultrastruktura MeSH
- mitochondrie účinky léků ultrastruktura MeSH
- Schizosaccharomyces účinky léků ultrastruktura MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- 2-methylbenzimidazole MeSH Prohlížeč
- benomyl MeSH
- benzimidazoly MeSH
- cytochalasin D MeSH
Cytochalasin D, an inhibitor of actin polymerization, interferes with ascogonial differentiation in the fertile fluffy mutant of Neurospora crassa. As the total level of actin and its mRNA remain unchanged, this suggests that it is in its microfilamentous form (F-form) that actin is stringently required for female differentiation.
- MeSH
- aktiny fyziologie MeSH
- cytochalasin D farmakologie MeSH
- fungální proteiny biosyntéza fyziologie MeSH
- fungální RNA biosyntéza MeSH
- messenger RNA biosyntéza MeSH
- Neurospora crassa cytologie účinky léků genetika MeSH
- rozmnožování MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- aktiny MeSH
- cytochalasin D MeSH
- fungální proteiny MeSH
- fungální RNA MeSH
- messenger RNA MeSH
