Association of the male and female pronuclei: the concluding events of fertilization
Frank J. Longo in Fertilization, 2020
The end of the migration of the male and female pronuclei is their juxtaposition. At the time of their association the male and female pronuclei of zygotes having the Ascaris type of fertilization are large spheroids. The pronuclei may fuse to produce a single zygote nucleus that later undergoes mitosis. Eggs exhibiting such a process are said to have the sea-urchin type of fertilization. However, aside from the differences and similarities exhibited in fertilized eggs from various organisms, the fact of primary importance is the bringing together of two originally separated lines of heredity, thereby establishing the genetic composition of the embryo. A transient Ca' increase is occasionally observed just prior to breakdown of the pronuclear envelopes that may be causal to processes characteristic of prophase nuclei. The pronuclei may become closely apposed and form nucleoplasmic projections that may interdigitate.
Mitosis
Dennis Bray in Cell Movements, 2000
This chapter is concerned with nuclear division of mitosis in a typical vertebrate cell. It shows that spindle microtubules, gaining access to the nuclear compartment, attach to chromosomal kinetochores. The chapter examines that in order to account for the erratic movements of chromosomes at metaphase, the kinetochore attachment must be of a special kind. During mitosis in plant and animal cells, populations of microtubules grow, attach to chromosomes, and maneuver them with amazing precision into two newly created nuclei. Mitosis itself is traditionally subdivided into a sequence of stages according to the behavior of the chromosomes, the principal stages being prophase, metaphase, anaphase , and telophase . Mitosis is not the only event in which chromosomes are moved within the cell. Sexual reproduction also requires extensive rearrangements of the genetic material under the guidance of microtubules.
PSO-Based Optimized Machine Learning Algorithms for the Prediction of Alzheimer’s Disease
Sandeep Kumar, Shilpa Rani, K. Ramya Laxmi in Artificial Intelligence and Machine Learning in 2D/3D Medical Image Processing, 2020
Alzheimer's Disease (AD) is one of the most common types of diseases amongst older adults. The primary reason for death in senior citizens is Alzheimer's related. To prevent Alzheimer's and provide early treatment, we have to accurately diagnosis Alzheimer's Disease and its prophase, which is called Mild Cognitive Impairment (MCI) in the healthcare sector. In this study, we have used seven machine learning classification methods for the prediction of Alzheimer's Disease. To recognize the type or stage of disease, it is essential to classify medical data and potentially develop a prediction model or system. The framework that we have developed consists of machine learning methods with Particle Swarm Optimization (PSO) and has been successfully applied to the classification of AD and dementia. For the prediction of Alzheimer's Disease, we have used seven machine learning Algorithms such as Support Vector Machine Classification, Random Forest Classification, XgBoost Classifier, Decision Tree Classification, Adaboost Classifier, K-Neighbour Classifier, and Logistic Regression. Our best-proposed method is the Random Forest Classifier, which achieves the greatest accuracy of 85.71%.
Role of phospholipase C in nuclear envelope assembly
Published in Clinical Lipidology, 2009
Richard D. Byrne, Dominic L. Poccia, Banafshé Larijani
The nuclear envelope is a dynamic double-bilayer membrane that segregates the nucleus from the cytoplasm. During mitosis it breaks down in prophase and is reformed around the daughter chromosomes in late anaphase/telophase. A similar nuclear envelope disassembly/assembly process takes place at fertilization around the sperm nucleus shortly after the sperm has penetrated the egg. Cell-free systems modeling the latter event have been devised in several non-mammalian species and are routinely used as models for somatic nuclear envelope formation. They pose several advantages over working with more complex systems and to date a number of seminal discoveries in nuclear envelope formation have been made using such systems. We have used a cell-free system derived from sea urchin gametes to study the role of membrane fusion events in nuclear envelope formation, with particular attention to the role of phosphoinositide lipids and PLCã. This review will describe our findings and discuss how they integrate into the current model of nuclear envelope formation.
Proteins Involved in Meiotic Recombination: A Role in Male Infertility?
Published in Systems Biology in Reproductive Medicine, 2008
Matthew L. Sanderson, Terry J. Hassold, Douglas T. Carrell
Meiotic recombination results in the formation of crossovers, by which genetic information is exchanged between homologous chromosomes during prophase I of meiosis. Recombination is a complex process involving many proteins. Alterations in the genes involved in recombination may result in infertility. Molecular studies have improved our understanding of the roles and mechanisms of the proteins and protein complexes involved in recombination, some of which have function in mitotic cells as well as meiotic cells. Human gene sequencing studies have been performed for some of these genes and have provided further information on the phenotypes observed in some infertile individuals. However, further studies are needed to help elucidate the particular role(s) of a given protein and to increase our understanding of these protein systems. This review will focus on our current understanding of proteins involved in meiotic recombination from a genomic perspective, summarizing our current understanding of known mutations and single nucleotide polymorphisms that may affect male fertility by altering meiotic recombination.
A monoclonal antibody specific for prophase phosphorylation of histone deacetylase 1: a readout for early mitotic cells
Published in mAbs, 2016
Chiara V. Segré, Silvia Senese, Sara Loponte, Stefano Santaguida, Paolo Soffientini, Gabriela Grigorean, Mario Cinquanta, Giuseppe Ossolengo, Christian Seiser, Susanna Chiocca
Histone deacetylases (HDACs) are modification enzymes that regulate a plethora of biological processes. HDAC1, a crucial epigenetic modifier, is deregulated in cancer and subjected to a variety of post-translational modifications. Here, we describe the generation of a new monoclonal antibody that specifically recognizes a novel highly dynamic prophase phosphorylation of serine 406-HDAC1, providing a powerful tool for detecting early mitotic cells.
Related Knowledge Centers
- Chromosomes
- Crossing Over
- Spindle Apparatus
- Meiosis
- Mitosis
- Centrioles
- Phase