The Role Of Metaphase II Arrest ( M II )

With sperm, each cell goes through meiosis to produce four sperm cells. During oogenesis a oogonium cell undergoes mitosis to produce primary oocytes. It differs from sperm formation because it is a stop-start process. It also divides the cell unequally and one primary oogonium cell produces one active cell in contrast to sperm.

Charlene Forest is an associate professor in the Biology department at Brooklyn College, who dedicates her research in to trying to understand the mechanism behind the process of fertilization in algae, as well as what controls expression of gamete-specific genes. To do so, she must understand how sperm and egg gametes first recognize and then fuse with each other. Thus, in order to find what causes the fusion of these gametes, Forest’s lab is cloning genes that prevent the fusion of sperm and egg gametes. She hopes that her research on the fertilization process in algae will help understand the fertilization process in other organisms, particularly humans.

Phosphodiesterases (PDEs) are a class of enzymes, which are responsible for the breakdown of phosphodiester bonds, specifically hydrolysing cyclic nucleotides, like the secondary messenger molecules cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in the striatal region of the brain.1 Via their control of both cAMP and cGMP in the cell, PDEs contribute to cell signalling making them potentially important drug targets.2 This enzyme class consists of 11 different families, PDE1 to PDE11, which vary in sequence homology, domain architecture and sequence homology.1 PDE10A is a PDE of current interest as a possible target to treat neurological diseases such as Schizophrenia and

Although the mbk-2 mutation has been researched, there is not much understood about the effect of the mutation on the distribution of P granules. Although samp-1 demonstrated the strongest suppression of the mbk-2 phenotype, its distribution of P granules was the most disordered. In these embryos, the granules had localized once again to the P2 blastomere by the four-cell stage. npp-19 and gtbp-1 were the only other suppressors that localized the P granules to the P2 blastomere, although it was only samp-1 cells that demonstrated wild-type meiotic cell division. This could indicate that proper cell division and P granule localization to P2 by the four-cell stage should be restored in order for the worms to develop past the L3 stage. Pang

protein kinase Akt, thus activating it as well. Akt is a free moving kinase inside the

Cell cycle control in mammalian cells is a complex mechanism and is regulated by cyclin-dependent kinases (CDKs) and their activating co-enzyme cyclins (A, B, D, and E).

Instead, the metabolites of glycolysis are used for production of NADPH or ribose-5-phosphate through the PPP or for lactate or alanine production. The significance of this immature morphology may be that since there is a decrease in OXPHOS, and thus a decrease in generation of ROS, there could be a reduction in apoptosis (Liu et al., 2000). As embryos develop and the first differentiation event occurs when TE are formed in blastocyst stage embryos, a transformational change is also detected in the mitochondria morphology. During this differentiation event, the mitochondria of the TE become elongated with well-developed traverse cristae and are more similar to the somatic cell morphology (Sathananthan and Trounson, 2000). This transformation of mitochondria in the TE to be more somatic cell like, corresponds to the time when the embryo starts using more glucose and metabolizing it through the TCA and OXPHOS. The ICM still contain immature mitochondria with round morphology. The mitochondria in the oocyte and early embryo are quite dynamic

An egg at each developmental stage (24, 28, 72, and 96 hour) were obtained with their blunt end positioned up because the embryo will be sitting just below the air space, while the yolk gravitates to the bottom. Each egg was opened from the blunt end by removing the shell membranes with forceps and scissors. The embryos of each stage were taken out by a technique that consisted of the embryo attaching to a filter paper, and then getting cut around the ring with scissors. The embryo was transferred to a small petri dish with Howard’s Ringer’s solution. Each embryo was examined and compared to one another.

new cycle starts after mitosis when two centrosomes separate into two daughter cells. The formation of a procentriole is initiated by the stalk and cartwheel assembling from the side of the mother centriole. During the initiation, PLK4 accumulates at the bottom of mother centriole, in conjunction with CEP152 and CEP192, which form rings around the circumference of the centriole. Next, PLK4 promotes the assembly of a stalk and nine-fold symmetric cartwheel that will platform the procentriole and engage it to the mother centriole (Kim et al., 2013; Sonnen et al., 2013). Also, SASS6, a structural component of the cartwheel, as well as its binding partner STIL, is recruited to the site of procentriole formation by PLK4 (Arquint and Nigg, 2014;

As soon as sperm cells are deposited in the female reproductive tract and pass the cervical mucus, they undergo many biochemical and physiological changes, including changes in the pattern of sperm motility known as hyperactivation, and the sperm become competent to fertilize an oocyte, in a process called capacitation 21,22. The biochemical changes that occur in this process include an efflux of cholesterol from the plasma membrane leading to an increase in membrane fluidity and permeability to bicarbonate and calcium ions which results in an increase in bicarbonate (HCO3-) concentration and intracellular pH, Ca2+, and cyclic adenosine monophosphate (cAMP) levels. 4,23.

fertilisation of the ovum takes place, however this happens as the expanded end, opening into the

the result of a complex series of processes that lead to the attachment of endometrial cells to

During a cell division, it is believed that genomic instability is minimized by four major mechanisms, which include chromosome segregation in

The study of Drosophila oogenesis provides invaluable information about signaling pathway regulation and cell cycle programming. During Drosophila oogenesis, a string of egg chambers in each ovariole progressively develops toward maturity. Egg chamber development consists of 14 stages. From stage 1 to stage 6 (mitotic cycle), mainbody follicle cells undergo mitotic divisions. From stage 7 to stage 10a (endocycle), follicle cells cease mitosis but continue another three rounds of endoreduplication. From stage 10a to stage 13 (gene amplification), instead of whole genome duplication, follicle cells selectively amplify specific genomic regions, mostly for chorion production. So far, Drosophila oogenesis is one of the most well-studied model systems to understand cell cycle switches, which furthers our knowledge about cell cycle control machinery and sheds new light on potential cancer treatments. Here, we give a brief summary of cell cycle switches, their involved signaling pathways and factors, and detailed experimental procedures to

However, that is not entirely true. The white circle here symbolises the cell and the big orange circle inside the white circle symbolises the nucleus. Inside the nucleus, the cell prepares itself for mitosis. At the start of interphase, the cell’s DNA exists in the form of a uncondensed chromatin.