The growth of supernumerary legs in the cockroach

Development ◽  
1986 ◽  
Vol 92 (1) ◽  
pp. 115-131
Author(s):  
Paul R. Truby
Keyword(s):  
Wound Healing ◽  
Cell Division ◽  
Rapid Rate ◽  
Large Area ◽  
Anteroposterior Axis ◽  
Cell Divisions ◽  
Leucophaea Maderae ◽  
Different Types ◽  
Local Cell

When the anteroposterior axis of a cockroach leg is reversed at a graft by exchanging a left leg for a right leg at the mid-tibia level, regeneration occurs in the region of the graft/host junction. This results in the formation of a pair of lateral supernumerary legs. In these experiments the patterns of cell division which take place during supernumerary leg formation were observed in sections of regenerating legs of the cockroach Leucophaea maderae. Early patterns of cell division resemble those seen in control grafts in which no axial reversal had been carried out during grafting. These cell divisions are associated with the process of wound healing. Later, a large area of the epidermis proximal to the graft/host junction becomes activated and shows a rapid rate of cell division. This area forms two outgrowths which grow by cell division throughout their epidermis to form the epidermis of the supernumerary legs. The results are more consistent with the view that the formation of supernumerary legs involves dedifferentiation of the epidermis in the region of the graft/host junction to form a blastema, rather than being due to local cell division at the point of maximum pattern discontinuity. This conclusion is used to offer an explanation for the range of different types of outcome of left-right grafts that has been observed.

Unequal cleavage in leech embryos: zygotic transcription is required for correct spindle orientation in subset of early blastomeres

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 599-606
Author(s):  
S.T. Bissen ◽  
C.M. Smith
Keyword(s):  
Cell Division ◽  
Early Period ◽  
Spindle Orientation ◽  
Mitotic Spindles ◽  
Maternal Control ◽  
Transcription Analysis ◽  
Cell Divisions ◽  
Zygotic Transcription ◽  
Different Types ◽  
Alpha Amanitin

Leech embryos undergo invariant sequences of equal and unequal cell divisions to give rise to identifiable progeny cells. While many of the early cleavages are under maternal control, the divisions of a subset of early blastomeres (the large cells of the D' lineage) are perturbed after the inhibition of zygotic transcription. Analysis of the different types of cells produced in embryos injected with the transcriptional inhibitor, alpha-amanitin, revealed that the symmetry of cell division is perturbed in these large D'-derived cells during this early period of development. These cells, which would normally undergo a series of equal and unequal cleavages, always undergo equal cleavages after the inhibition of zygotic transcription. It appears that zygotically transcribed gene product(s) are required in the large cells of the D' lineage to orient the mitotic spindles properly for these unequal cell cleavages.

Ultrastructure of cell division in Cladophora. Pregametangial cell division in the haploid generation of Cladophora flexuosa

1976 ◽  
Vol 54 (13) ◽  
pp. 1546-1560 ◽  
Author(s):  
J. L. Scott ◽  
K. W. Bullock
Keyword(s):  
Life History ◽  
Electron Microscope ◽  
Cell Division ◽  
Nuclear Envelope ◽  
Double Membrane ◽  
Cell Divisions ◽  
Gamete Formation ◽  
Reproductive Differentiation ◽  
Different Types ◽  
Vacuolar System

Cell division preceding gamete formation in the haploid generation of Cladophora flexuosa was studied with the electron microscope. Numerous, asynchronous mitotic nuclear divisions are concurrent with the progressive cleavage of the cytoplasm by invaginations of a central and peripheral vacuolar system. The spindle is enclosed by the nuclear envelope during all stages of mitosis and is associated with polar centriole pairs. The cytokinetic process is not associated with microtubules and is basically similar to that observed in other macroscopic, multinucleate green algae. Unusual mitochondria, characterized by specialized double-membrane-enclosed, presumptive DNA regions, were found during the later stages of reproductive differentiation. It is emphasized that the different types of cell divisions which can occur in plants possessing a haplodiplontic type of life history should all be thoroughly examined before the establishment of a particular mitotic sequence for any given species.

Cytoplasmic Structures in Insect Granular Hemocytes

1971 ◽  
Vol 29 ◽  
pp. 528-529
Author(s):  
M. Hagopian
Keyword(s):  
Electron Microscopy ◽  
Wound Healing ◽  
Fine Structure ◽  
Circulatory System ◽  
Cellular Function ◽  
Large Nucleus ◽  
Cytoplasmic Granules ◽  
Leucophaea Maderae ◽  
Different Types ◽  
Cytoplasmic Structures

Femoral segments from the metathoracic leg of the freshly molted cockroach nymph, Leucophaea maderae, were removed and were prepared for electron microscopy. The femoral cuticle with underlying epidermal cells encloses muscle, nerves, tracheae, tracheoles, and the hemocoel. In the insect open circulatory system the hemocoel contains hemolymph and hemocytes. Some of the known functions of insect hemocytes are phagocytosis, encapsulation, melanization, Wound healing, coagulation and possible transformation into other tissues. Previous studies of the agranular and granular hemocytes however lack the fine structure that is helpful in determining cellular function.The several different types of granular hemocytes have a general elliptical appearance, large nucleus, and prominent cytoplasmic granules. The most abundant type of granules are the membrane-bounded, roughly spherical, opaque inclusions which average about 1 to 2μ in diameter. These dense inclusions resemble vertebrate melanosomes. Other granules with an organized substructure are reminiscent of the vertebrate premelanosomes (Figs. 1, 2). In certain planes of section the premelanosome-like granules reveal that the internal configurations are microtubules which measure about 250A in diameter.

Cell division during intercalary regeneration in the cockroach leg

Development ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 57-78
Author(s):  
Hilary Anderson ◽  
Vernon French
Keyword(s):  
Wound Healing ◽  
Cell Division ◽  
Epidermal Cells ◽  
Moult Cycle ◽  
Intercalary Regeneration ◽  
Polar Coordinate ◽  
Coordinate Model ◽  
Local Cell ◽  
Cuticular Structures ◽  
Pattern Regulation

In a series of grafting operations on cockroach legs, epidermal cells from different positions or from the same position on the circumference of the femur were placed together. Where cells from different positions were confronted, new cuticular structures corresponding to the positions which would normally have lain between them were formed during the following moults. At the control junctions, where cells from the same positions were placed together, no new structures were formed. Grafted legs were examined histologically at various times after the operation. The events following grafting fell into four phases: wound healing — when epidermal cells migrated over the wound to re-establish epidermal continuity and cells adjacent to the wound divided to compensate for cell emigration; intercalation — when cell divisions took place at the host-graft borders where there was a positional discrepancy; proliferation — when the general growth of the epidermis occurred by widespread cell division; cuticle secretion — when apolysis occurred, cell division ceased, and cuticle secretion began. The results show that intercalary regeneration is associated with local cell division at the graft-host borders, and that these divisions are not confined to the normal proliferative phase of the moult cycle, but begin much earlier in the cycle, as soon as wound healing is complete. These results support epimorphic models (such as the Polar Coordinate Model) of pattern regulation, where change of positional value is tied to cell division, but they do not discount the possibility of a limited initial morphallactic phase.

Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

1970 ◽  
Vol 28 ◽  
pp. 186-187
Author(s):  
Krishan Awtar
Keyword(s):  
Cell Division ◽  
Normal Cell ◽  
Virus Production ◽  
Multinucleate Cells ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Nuclear Membranes ◽  
Division 2 ◽  
Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

scholarly journals The Role of Non-Coding RNAs in the Regulation of the Proto-Oncogene MYC in Different Types of Cancer

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 921
Author(s):  
Ekaterina Mikhailovna Stasevich ◽  
Matvey Mikhailovich Murashko ◽  
Lyudmila Sergeevna Zinevich ◽  
Denis Eriksonovich Demin ◽  
Anton Markovich Schwartz
Keyword(s):  
Malignant Tumors ◽  
Current Data ◽  
Cellular Processes ◽  
Cell Divisions ◽  
Specific Tumor ◽  
Different Types ◽  
Myc Gene ◽  
Non Coding Rnas ◽  
Tumor Types

Alterations in the expression level of the MYC gene are often found in the cells of various malignant tumors. Overexpressed MYC has been shown to stimulate the main processes of oncogenesis: uncontrolled growth, unlimited cell divisions, avoidance of apoptosis and immune response, changes in cellular metabolism, genomic instability, metastasis, and angiogenesis. Thus, controlling the expression of MYC is considered as an approach for targeted cancer treatment. Since c-Myc is also a crucial regulator of many cellular processes in healthy cells, it is necessary to find ways for selective regulation of MYC expression in tumor cells. Many recent studies have demonstrated that non-coding RNAs play an important role in the regulation of the transcription and translation of this gene and some RNAs directly interact with the c-Myc protein, affecting its stability. In this review, we summarize current data on the regulation of MYC by various non-coding RNAs that can potentially be targeted in specific tumor types.

discordia mutations specifically misorient asymmetric cell divisions during development of the maize leaf epidermis

Development ◽  
1999 ◽  
Vol 126 (20) ◽  
pp. 4623-4633 ◽  
Author(s):  
K. Gallagher ◽  
L.G. Smith
Keyword(s):  
Cell Division ◽  
Preprophase Band ◽  
Cytochalasin D ◽  
Leaf Epidermis ◽  
Asymmetric Cell Divisions ◽  
Maize Leaf ◽  
Cell Divisions ◽  
Cytoskeletal Structure ◽  
Dividing Cells ◽  
Preprophase Bands

In plant cells, cytokinesis depends on a cytoskeletal structure called a phragmoplast, which directs the formation of a new cell wall between daughter nuclei after mitosis. The orientation of cell division depends on guidance of the phragmoplast during cytokinesis to a cortical site marked throughout prophase by another cytoskeletal structure called a preprophase band. Asymmetrically dividing cells become polarized and form asymmetric preprophase bands prior to mitosis; phragmoplasts are subsequently guided to these asymmetric cortical sites to form daughter cells of different shapes and/or sizes. Here we describe two new recessive mutations, discordia1 (dcd1) and discordia2 (dcd2), which disrupt the spatial regulation of cytokinesis during asymmetric cell divisions. Both mutations disrupt four classes of asymmetric cell divisions during the development of the maize leaf epidermis, without affecting the symmetric divisions through which most epidermal cells arise. The effects of dcd mutations on asymmetric cell division can be mimicked by cytochalasin D treatment, and divisions affected by dcd1 are hypersensitive to the effects of cytochalasin D. Analysis of actin and microtubule organization in these mutants showed no effect of either mutation on cell polarity, or on formation and localization of preprophase bands and spindles. In mutant cells, phragmoplasts in asymmetrically dividing cells are structurally normal and are initiated in the correct location, but often fail to move to the position formerly occupied by the preprophase band. We propose that dcd mutations disrupt an actin-dependent process necessary for the guidance of phragmoplasts during cytokinesis in asymmetrically dividing cells.

Modification of cell division by phorbol ester in preimplantation mouse embryos

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 403-408
Author(s):  
E.T. Mystkowska ◽  
W. Sawicki
Keyword(s):  
Cell Division ◽  
Video Recording ◽  
Mouse Embryos ◽  
Time Intervals ◽  
Cell Divisions ◽  
Stage Of Development ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Single Blastomeres

2-cell mouse embryos were treated in vitro with a 2 h pulse of phorbol myristate acetate (PMA) at 32nd, 38th and 50th h after hCG, then chased in culture for up to 46 h. Embryos were fixed at various time intervals of chasing, then stained and inspected. Some embryos were carefully inspected with a video recording system, every 1.44s and the cell divisions (cytokinesis) as well as formation of large, single blastomeres, each from two smaller ones, were recorded. PMA pulse let to the suppression of cell divisions. The rate of the suppression was time dependent: with a delay of 0–1, 12 and 18 h between the PMA pulse and time of scheduled cell division about 99, 87 and 44% of 2-cell embryos remained at this stage of development, for at least 10 h, respectively, and 90, 58 and 12% of their blastomeres revealed binuclearity. Since we found that PMA-mediated formation of binuclearity was not the effect of cell fusions, it was assumed that the inhibition of cytokinesis preceded by karyokinesis was responsible for binuclearity. PMA effect on cell divisions was reversible. PMA-treated embryos revealed formation of large, single blastomeres, each from two smaller ones. If cell division appeared after PMA pulse, in about 52% of 3- to 6-cell embryos, the large blastomere formation was recorded in the course of the subsequent 38 h. Large blastomere formation was concluded to be the result of either cell fusion or reversion of incompleted cytokinesis brought about by PMA.

scholarly journals Cografts of artificial dermis matrix and autogenetic split-thickness of repaired skin in severe hand wounds in patients with deep burns

2014 ◽  
Vol 66 (1) ◽  
pp. 173-178
Author(s):  
Hongqi Liu ◽  
Yan Li ◽  
Deqian Sha
Keyword(s):  
Wound Healing ◽  
Hand Function ◽  
Donor Site ◽  
Test Group ◽  
Healing Time ◽  
Whole Body ◽  
Control Group ◽  
Large Area ◽  
Artificial Dermis ◽  
Thickness Skin

The aim of this paper was to evaluate the effect of using artificial dermis matrix plus autologous split-thickness skin (ADM and ASTS) in the treatment of deep-burns in hands of severely burned patients?We recruited a total of 58 patients with large area burns greater than 80% that were eschar-excised. Twenty-eight of them were treated with ADM and ASTS (test group); 30 were treated with autologous medium-thickness skin (AMTS) (control group). The healing time of the hand wound was noted, clinical and photographic evaluations were performed, and a Jebsen-Taylor hand function test was compared and analyzed in the two groups. The wound healing time in the test group (24.22?3.34 days) were longer than that of the control group (13.42?3.36 days) and statistically significant. The healing time of skin graft donor sites was shorter than that of the control group (7.14?1.63 vs. 14.28?2.37 days) and statistically significant (P<0.05). The 3rd and 6th month follow-up with clinical and functional evaluations revealed no differences between the two groups. In addition, there was no obvious scar formation and less pigmentation in either group. The repair of deeply burned hands with artificial dermis matrix was beneficial to both wound healing and the donor site, and was beneficial to the whole body rehabilitation of severely burned patients.

scholarly journals The Regenerative Potential of Substance P

2022 ◽  
Vol 23 (2) ◽  
pp. 750
Author(s):  
Patrycja Redkiewicz
Keyword(s):  
Wound Healing ◽  
Substance P ◽  
Autoimmune Diseases ◽  
Chronic Wounds ◽  
Different Types ◽  
Healing Wounds ◽  
Active Substances

Wound healing is a highly coordinated process which leads to the repair and regeneration of damaged tissue. Still, numerous diseases such as diabetes, venous insufficiencies or autoimmune diseases could disturb proper wound healing and lead to chronic and non-healing wounds, which are still a great challenge for medicine. For many years, research has been carried out on finding new therapeutics which improve the healing of chronic wounds. One of the most extensively studied active substances that has been widely tested in the treatment of different types of wounds was Substance P (SP). SP is one of the main neuropeptides released by nervous fibers in responses to injury. This review provides a thorough overview of the application of SP in different types of wound models and assesses its efficacy in wound healing.

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