scholarly journals The Drosophila Kinesin-13, KLP59D, Impacts Pacman- and Flux-based Chromosome Movement

2009 ◽  
Vol 20 (22) ◽  
pp. 4696-4705 ◽  
Author(s):  
Uttama Rath ◽  
Gregory C. Rogers ◽  
Dongyan Tan ◽  
Maria Ana Gomez-Ferreria ◽  
Daniel W. Buster ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Family Member ◽  
Somatic Cells ◽  
Spindle Pole ◽  
The Other ◽  
Chromosome Movement ◽  
Spindle Microtubule ◽  
Important Regulator ◽  
Chromosome Movements

Chromosome movements are linked to the active depolymerization of spindle microtubule (MT) ends. Here we identify the kinesin-13 family member, KLP59D, as a novel and uniquely important regulator of spindle MT dynamics and chromosome motility in Drosophila somatic cells. During prometaphase and metaphase, depletion of KLP59D, which targets to centrosomes and outer kinetochores, suppresses the depolymerization of spindle pole–associated MT minus ends, thereby inhibiting poleward tubulin Flux. Subsequently, during anaphase, loss of KLP59D strongly attenuates chromatid-to-pole motion by suppressing the depolymerization of both minus and plus ends of kinetochore-associated MTs. The mechanism of KLP59D's impact on spindle MT plus and minus ends appears to differ. Our data support a model in which KLP59D directly depolymerizes kinetochore-associated plus ends during anaphase, but influences minus ends indirectly by localizing the pole-associated MT depolymerase KLP10A. Finally, electron microscopy indicates that, unlike the other Drosophila kinesin-13s, KLP59D is largely incapable of oligomerizing into MT-associated rings in vitro, suggesting that such structures are not a requisite feature of kinetochore-based MT disassembly and chromosome movements.

scholarly journals In VitroAdherence of Oral Bacteria to Different Types of Tongue Piercings

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lucas Pereira Borges ◽  
Julio Cesar Campos Ferreira-Filho ◽  
Julia Medeiros Martins ◽  
Caroline Vieira Alves ◽  
Bianca Marques Santiago ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Adhesion ◽  
Oral Bacteria ◽  
The Other ◽  
Control Group ◽  
Colony Forming Units ◽  
Different Types ◽  
Scanning Electron

The purpose of this work was to verifyin vitroadherence ofE. corrodensandS. oralisto the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5 mL of BHI broth and 50 μL of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis (pvalue<0.05). ForE. corrodens, difference among types of material was observed (p<0.001) and titanium and surgical steel showed lower bacterial adherence. The adherence ofS. oralisdiffered among piercings, showing lower colonization (p<0.007) in titanium and surgical steel piercings. The four types of piercings were susceptible to colonization byE. corrodensandS. oralis, and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

scholarly journals Evidence that myosin does not contribute to force production in chromosome movement.

1982 ◽  
Vol 94 (1) ◽  
pp. 165-178 ◽  
Author(s):  
D P Kiehart ◽  
I Mabuchi ◽  
S Inoué
Keyword(s):  
Gamma Globulin ◽  
Meiotic Chromosome ◽  
Force Production ◽  
Chromosome Movement ◽  
Actomyosin Interaction ◽  
Dividing Cells ◽  
Spindle Elongation ◽  
Chromosome Movements

Antibody against cytoplasmic myosin, when microinjected into actively dividing cells, provides a physiological test for the role of actin and myosin in chromosome movement. Anti-Asterias egg myosin, characterized by Mabuchi and Okuno (1977, J. Cell Biol., 74:251), completely and specifically inhibits the actin activated Mg++ -ATPase of myosin in vitro and, when microinjected, inhibits cytokinesis in vivo. Here, we demonstrate that microinjected antibody has no observable effect on the rate or extent of anaphase chromosome movements. Neither central spindle elongation nor chromosomal fiber shortening is affected by doses up to eightfold higher than those require to uniformly inhibit cytokinesis in all injected cells. We calculate that such doses are sufficient to completely inhibit myosin ATPase activity in these cells. Cells injected with buffer alone, with myosin-absorbed antibody, or with nonimmune gamma-globulin, proceed normally through both mitosis and cytokinesis. Control gamma-globulin, labeled with fluorescein, diffuses to homogeneity throughout the cytoplasm in 2-4 min and remains uniformly distributed. Antibody is not excluded from the spindle region. Prometaphase chromosome movements, fertilization, pronuclear migration, and pronuclear fusion are also unaffected by microinjected antimyosin. These experiments demonstrate that antimyosin blocks the actomyosin interaction thought to be responsible for force production in cytokinesis but has no effect on mitotic or meiotic chromosome motion. They provide direct physiological evidence that myosin is not involved in force production for chromosome movement.

scholarly journals Cell division in two large pennate diatoms Hantzschia and Nitzschia III. A new proposal for kinetochore function during prometaphase.

1980 ◽  
Vol 86 (2) ◽  
pp. 402-416 ◽  
Author(s):  
D H Tippit ◽  
J D Pickett-Heaps ◽  
R Leslie
Keyword(s):  
Electron Microscopy ◽  
Leading Edge ◽  
Time Lapse ◽  
Cell Types ◽  
Spindle Pole ◽  
Large Species ◽  
Conventional View ◽  
Chromosome Movements ◽  
Kinetochore Function

Prometaphase in two large species of diatoms is examined, using the following techniques: (a) time-lapse cinematography of chromosome movements in vivo; (b) electron microscopy of corresponding stages: (c) reconstruction of the microtubules (MTs) in the kinetochore fiber of chromosomes attached to the spindle. In vivo, the chromosomes independently commence oscillations back and forth to one pole. The kinetochore is usually at the leading edge of such chromosome movements; a variable time later both kinetochores undergo such oscillations but toward opposite poles and soon stretch poleward to establish stable bipolar attachment. Electron microscopy of early prometaphase shows that the kinetochores usually laterally associate with MTs that have one end attached to the spindle pole. At late prometaphase, most chromosomes are fully attached to the spindle, but the kinetochores on unattached chromosomes are bare of MTs. Reconstruction of the kinetochore fiber demonstrates that most of its MTs (96%) extend past the kinetochore and are thus apparently not nucleated there. At least one MT terminates at each kinetochore analyzed. Our interpretation is that the conventional view of kinetochore function cannot apply to diatoms. The kinetochore fiber in diatoms appears to be primarily composed of MTs from the poles, in contrast to the conventional view that many MTs of the kinetochore fiber are nucleated by the kinetochore. Similarly, chromosomes appear to initially orient their kinetochores to opposite poles by moving along MTs attached to the poles, instead of orientation effected by kinetochore MTs laterally associating with other MTs in the spindle. The function of the kinetochore in diatoms and other cell types is discussed.

155 EFFECT OF CO-CULTURE WITH CUMULUS-DERIVED SOMATIC CELLS DURING IN VITRO MATURATION ON PORCINE CUMULUS–OOCYTE COMPLEXES AND SUBSEQUENT EMBRYONIC DEVELOPMENT AFTER IN VITRO FERTILIZATION

2014 ◽  
Vol 26 (1) ◽  
pp. 191 ◽  
Author(s):  
J. D. Yoon ◽  
L. Cai ◽  
S. U. Hwang ◽  
Y. Jeon ◽  
E. Kim ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Mrna Expression ◽  
In Vitro Maturation ◽  
Somatic Cells ◽  
The Other ◽  
Control Group ◽  
Cortical Granules ◽  
Developmental Potential ◽  
Significant Difference

The purpose of this study was to investigate the effects of co-culture with cumulus-derived somatic cells (CSC) during porcine in vitro maturation (IVM) and subsequent embryonic development after IVF. The CSC were cultured in Dulbecco's modified Eagle medium for 48 h with various numbers of cumulus-derived somatic cells (0.0, 2.5, 5.0, and 10.0 × 104), and then cultured in TCM-199 for 4 h before the oocytes were added. Cumulus-oocytes complexes from 3- to 6-mm follicles were matured in 500 μL of TCM-199, with eCG and hCG, for 22 h, and then cultured in M199 without hormones for 22 h. Each experiment consisted of at least 4 replicates. Statistical analyses were carried out using SPSS 17.0 software (SPSS Inc., Chicago, IL). Percentage data were compared by one-way ANOVA, followed by Duncan's multiple range test. Data were presented as means ± s.e.m. Differences were considered to be significant if the P-value was 0.05. After IVM, no significant difference (P < 0.05) was observed in nuclear maturation rate among the 0.0, 2.5, 5.0, and 10.0 × 104 groups (88.0 ± 2.37, 81.5 ± 2.17, 87.0 ± 1.98 and 86.0 ± 1.93%, respectively). The 2.5 × 104 group showed a significant (P < 0.05) increase in intracellular glutathione (GSH) levels compared with that of the other groups. Intracellular reactive oxygen species (ROS) levels of mature oocyte in all groups showed no significant differences. The developmental competence of matured oocytes in all groups was evaluated after IVF. The 2.5 and 5.0 × 104 groups showed significantly (P < 0.05) high cleavage rates (60.0 ± 4.7 and 64.52 ± 5.9%, respectively) compared with the 0 and 10.0 × 104 groups (43.15 ± 5.0 and 53.8 ± 5.0%, respectively). The 2.5 × 104 group showed a significantly (P < 0.05) higher BL formation rate (35.7 ± 2.9) than control group (21.0 ± 3.8%, respectively), and higher total cell number (127.25 ± 7.7) compared with the 0 and 10 × 104 groups (89.3 ± 4.0 and 92.6 ± 3.7, respectively). In the analysis of gene expression, IVF-BL derived from the 2.5 and 5.0 × 104 groups showed higher (P < 0.05) mRNA expression of PCNA, which is an essential component of the DNA replication and repair machinery and POU5F1 has been used to evaluate developmental potential in embryos. The 10.0 × 104 group showed higher (P < 0.05) mRNA expression of caspase-3 and Bak as known pro-apoptotic factors, compared with the control group IVF-BL. The results of cortical granules distribution which leads digesting sperm receptor proteins ZP2 and ZP3 to block polyspermy, showed that the 2.5 × 104 group was increased significantly (P < 0.05) compared with the other co-culture groups (13.7 ± 6.1, 29.2 ± 9.5, 18.3 ± 0.8 and 19.52 ± 5.3, respectively). In conclusion, co-culture with 2.5 × 104 cumulus-derived somatic cells during IVM improved the developmental potential of porcine IVF embryos by increasing the intracellular GSH level and distribution of cortical granules during oocyte maturation. This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.

scholarly journals Regeneration and Reprogramming

2021 ◽  
pp. 135-149
Author(s):  
Renato Paro ◽  
Ueli Grossniklaus ◽  
Raffaella Santoro ◽  
Anton Wutz
Keyword(s):  
Stem Cells ◽  
Somatic Cells ◽  
Spare Parts ◽  
The Other ◽  
Developmental Potential ◽  
Organ Specific ◽  
Organ Repair ◽  
Restructuring Process ◽  
The One

AbstractDuring regenerative processes, cells are required to restructure parts of a damaged or worn-out organ and tissue. Here, you will become acquainted with the strategies that organisms developed to provide the material for tissue and organ repair. On the one hand, somatic cells can become dedifferentiated to increase their developmental potential and produce the plasticity required to replace the entire cellular complexity of a damaged part. On the other hand, organisms retain organ-specific stem cells with a restricted developmental potency and use these to provide the “spare parts” for replacing damaged cells. In all cases, a substantial reprogramming of the epigenome of these cells accompanies the restructuring process. In vitro strategies have been developed to drive cells back to a pluripotent state, allowing a better understanding of the underlying chromatin adjustments and providing a rich source for cellular therapies.

scholarly journals The absence of centrioles from spindle poles of rat kangaroo (PtK2) cells undergoing meiotic-like reduction division in vitro.

1977 ◽  
Vol 72 (2) ◽  
pp. 368-379 ◽  
Author(s):  
S Brenner ◽  
A Branch ◽  
S Meredith ◽  
M W Berns
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Time Lapse ◽  
Spindle Pole ◽  
Reduction Division ◽  
Daughter Cells ◽  
Spindle Poles ◽  
Spindle Apparatus ◽  
Time Lapse Photography

Light and electron microscopy were used to study somatic cell reduction division occurring spontaneously in tetraploid populations of rat kangaroo Potorous tridactylis (PtK2) cells in vitro. Light microscopy coupled with time-lapse photography documented the pattern of reduction division which includes an anaphase-like movement of double chromatid chromosomes to opposite spindle poles followed by the organization of two separate metaphase plates and synchronous anaphase division to form four poles and four daughter nuclei. The resulting daughter cells were isolated and cloned, showing their viability, and karyotyped to determine their ploidy. Ultrastructural analysis of cells undergoing reduction consistently revealed two duplexes of centrioles (one at each of two spindle poles) and two spindle poles in each cell that lacked centrioles but with microtubules terminating in a pericentriolar-like cloud of material. These results suggest that the centriole is not essential for spindle pole formation and division and implicate the could region as a necessary component of the spindle apparatus.

The differentiation of mouse gonads in vitro: a light and electron microscopical study

Development ◽  
1986 ◽  
Vol 97 (1) ◽  
pp. 189-199
Author(s):  
Sarah Mackay ◽  
Robert A. Smith
Keyword(s):  
Electron Microscopy ◽  
Culture Medium ◽  
Light And Electron Microscopy ◽  
Calf Serum ◽  
Microscopical Study ◽  
Electron Microscopical Study ◽  
The Other ◽  
Foetal Calf Serum ◽  
Electron Microscopical

Indifferent urogenital complexes were excised from mouse foetuses assessed by developmental criteria as day 10·5 or 11. After 4 or 6–7 days in culture, complexes were fixed and examined by light and electron microscopy. The effect of culturing sexed complexes in mixed sex groups was investigated. The effect of the presence or absence of foetal calf serum in the culture medium was considered. No evidence of inhibition of one sex by the other was found. Ovaries developed further in cultures than testes.

scholarly journals Microcephaly protein Asp focuses the minus ends of spindle microtubules at the pole and within the spindle

2015 ◽  
Vol 211 (5) ◽  
pp. 999-1009 ◽  
Author(s):  
Ami Ito ◽  
Gohta Goshima
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Model ◽  
Spindle Pole ◽  
Cross Linking ◽  
Dependent Manner ◽  
Spindle Microtubule ◽  
Cross Links ◽  
Spindle Microtubules ◽  
Insight Into

Depletion of Drosophila melanogaster Asp, an orthologue of microcephaly protein ASPM, causes spindle pole unfocusing during mitosis. However, it remains unclear how Asp contributes to pole focusing, a process that also requires the kinesin-14 motor Ncd. We show that Asp localizes to the minus ends of spindle microtubule (MT) bundles and focuses them to make the pole independent of Ncd. We identified a critical domain in Asp exhibiting MT cross-linking activity in vitro. Asp was also localized to, and focuses the minus ends of, intraspindle MTs that were nucleated in an augmin-dependent manner and translocated toward the poles by spindle MT flux. Ncd, in contrast, functioned as a global spindle coalescence factor not limited to MT ends. We propose a revised molecular model for spindle pole focusing in which Asp at the minus ends cross-links MTs at the pole and within the spindle. Additionally, this study provides new insight into the dynamics of intraspindle MTs by using Asp as a minus end marker.

scholarly journals Requirements for NuMA in maintenance and establishment of mammalian spindle poles

2009 ◽  
Vol 184 (5) ◽  
pp. 677-690 ◽  
Author(s):  
Alain D. Silk ◽  
Andrew J. Holland ◽  
Don W. Cleveland
Keyword(s):  
Mitotic Spindle ◽  
Somatic Cells ◽  
Spindle Pole ◽  
Primary Cells ◽  
Spindle Microtubule ◽  
Mitotic Apparatus ◽  
Process Thought ◽  
Direct Capture ◽  
Spindle Poles ◽  
Spindle Fibers

Microtubules of the mitotic spindle in mammalian somatic cells are focused at spindle poles, a process thought to include direct capture by astral microtubules of kinetochores and/or noncentrosomally nucleated microtubule bundles. By construction and analysis of a conditional loss of mitotic function allele of the nuclear mitotic apparatus (NuMA) protein in mice and cultured primary cells, we demonstrate that NuMA is an essential mitotic component with distinct contributions to the establishment and maintenance of focused spindle poles. When mitotic NuMA function is disrupted, centrosomes provide initial focusing activity, but continued centrosome attachment to spindle fibers under tension is defective, and the maintenance of focused kinetochore fibers at spindle poles throughout mitosis is prevented. Without centrosomes and NuMA, initial establishment of spindle microtubule focusing completely fails. Thus, NuMA is a defining feature of the mammalian spindle pole and functions as an essential tether linking bulk microtubules of the spindle to centrosomes.

scholarly journals The Kinesin-12 Kif15 is a processive track-switching tetramer

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Hauke Drechsler ◽  
Toni McHugh ◽  
Martin R Singleton ◽  
Nicholas J Carter ◽  
Andrew D McAinsh
Keyword(s):  
Spindle Motor ◽  
Human Protein ◽  
Cross Linking ◽  
Chromosome Movement ◽  
Spindle Microtubule ◽  
Mode Of Operation ◽  
Microtubule Networks ◽  
Kinesin Superfamily ◽  
Insight Into

Kinesin-12 motors are a little studied branch of the kinesin superfamily with the human protein (Kif15) implicated in spindle mechanics and chromosome movement. In this study, we reconstitute full-length hKif15 and its microtubule-targeting factor hTpx2 in vitro to gain insight into the motors mode of operation. We reveal that hKif15 is a plus-end-directed processive homotetramer that can step against loads of up to 3.5 pN. We further show that hKif15 is the first kinesin that effectively switches microtubule tracks at intersections, enabling it to navigate microtubule networks, such as the spindle. hKif15 tetramers are also capable of cross-linking microtubules, but unexpectedly, this does not depend on hTpx2. Instead, we find that hTpx2 inhibits hKif15 stepping when microtubule-bound. Our data reveal that hKif15 is a second tetrameric spindle motor in addition to the kinesin-5 Eg5 and provides insight into the mechanisms by which hKif15 and its inhibitor hTpx2 modulate spindle microtubule architecture.

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