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Animal Source Foods
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Protein is distributed in both egg white and yolk. Egg white is mainly composed of protein (11%), with ovalbumin being the most abundant (54%), followed by ovotransferrin (12%), ovomucoid (11%), lysozyme (3.5%), and ovomucin (3.5%) (111–115). Other minor proteins such as ovoglycoprotein, ovoflavoprotein, ovomacroglobulin, avidin, cystatin, and ovoinhibitor have also been identified (112, 114–115). The main components of the yolk are lipids (31–35%), although it also has 15–17% of proteins including lipovitellins (36%), livetins (38%), phosvitin (8%), and low-density lipoproteins (17%) (115). Egg yolk is covered with the vitelline membrane which separates it from the egg white. It is also a good source of proteins, being composed mostly of protein fibers (115).
Motility Parameters and Fertility
Published in Claude Gagnon, Controls of Sperm Motility, 2020
An approach which has been frequently used to determine the relationship between sperm movement characteristics and sperm function has been to correlate the former with the outcome of the zona-free hamster oocyte penetration test.3 This in vitro procedure generates information on the ability of human spermatozoa to acrosome react and fuse with the vitelline membrane of the oocyte. As a criterion of sperm function, it has been shown to be highly predicitve of the ability of human spermatozoa to fertilize human oocytes in vitro,16 particularly when the divalent cation ionophore A23187 is used to induce the acrosome reaction as a surrogate for the human zona pellucida. In addition, this test of sperm-oocyte fusion has been shown to generate data of diagnostic value in vivo, particularly when the semen profile is otherwise normal as in cases of unexplained infertility18 or when assessing the fertility of donors in an Artificial Insemination by Donor (AID) clinic.19
Prostaglandins and Semen
Published in Murray D. Mitchell, Eicosanoids in Reproduction, 2020
Before a mature, ejaculated spermatozoon can fertilize an egg, it undergoes a process termed capacitation which allows it to acrosome react, a procedure associated with the ingress of calcium ions, resulting in the loss of the acrosome. The acrosome reaction is an essential preliminary to sperm-oocyte fusion. This fusion is not normally possible when the egg and the sperm are from different species since a block to interspecific fertilization is found at the zona pellucida, which surrounds the egg, the vitelline membrane, or both. In the case of the hamster, the block is solely at the zona pellucida, which can be removed with tryspin, allowing a human (or any other species) spermatozoon to fuse with and “fertilize” the egg. The observation of this phenomenon, and in particular the scoring of the decondensed sperm heads, allows an objective assessment of the acrosome reaction.
Characterization and toxicology evaluation of zirconium oxide nanoparticles on the embryonic development of zebrafish, Danio rerio
Published in Drug and Chemical Toxicology, 2019
Karthiga P., Ponnanikajamideen M., R. Samuel Rajendran, Gurusamy Annadurai, S. Rajeshkumar
The embryonic Zebrafish has shown its enormous potential as an in vivo model for nanomaterials toxicity studies. Zirconia nanoparticles (size 15–20 nm) at a lower and high concentration affected the developmental processes. Zebrafish eggs (1.0–1.2 mm in diameter) consists of two membranes, a chorionic and vitelline membrane with a perivitelline space (Kalicharan et al.1998). The chorion consists of minute pore canals, size roughly about 0.5–0.7 µm in diameter that is a vital role for the transport of oxygen/carbon dioxide, nutrients and excretory materials in and out from the embryo (Rawson et al.2000, Lee et al.2007, Sun et al.2016).
Using Xenopus oocytes in neurological disease drug discovery
Published in Expert Opinion on Drug Discovery, 2020
Steven L. Zeng, Leland C. Sudlow, Mikhail Y. Berezin
One of the major requirements and challenges to performing patch clamping with oocytes is a clean and readily accessible surface that is protected by the vitelline membrane. This outer membrane composed from glycoproteins provides the oocyte’ structural rigidity and keeps the oocytes in a spherical shape. The vitelline membrane is usually removed either manually with forceps (most common, but also demanding fine motor skills) or with the collagenase treatment that dissolves the membrane [67]. Due to the high vulnerability of devitellinized oocytes, extreme care must be taken to handle the oocytes for electrophysiological recording.
Nanoparticles as a potential teratogen: a lesson learnt from fruit fly
Published in Nanotoxicology, 2019
Bedanta Kumar Barik, Monalisa Mishra
Stress at cellular level resulted in an enhanced expression level of heat shock proteins (Hsp), activates the JNK pathway, and induces autophagy in Drosophila (Stronach and Perrimon 1999; Scott et al. 2004; Simonsen et al. 2007; Singh, Reddy et al. 2009). Janus Kinase (JNK) protein has been found to enhance tolerance to oxidative damage and longevity in both Drosophila and C. elegans model system (Wang et al. 2003; Oh et al. 2005). HSP or stress proteins are synthesized when induced by foreign inducers and their conservative property with ability to induced by a large number of environmental inducers make it a suitable molecule for tracing the effect of stressors (Lindquist 1986; Aıt-Aıssa et al. 2000; Mukhopadhyay et al. 2003; Siddique et al. 2008). Hsp70 is used as a biomarker in most of the NP toxicity studies (Bierkens 2000). Heat and oxidative stress during Drosophila development hamper synthesis of biogenic amines and hormones such as dopamine, octopamine, juvenile hormone, ecdysteroids, which has a major role in reproduction (Rauschenbach et al. 1995; Gruntenko et al. 2003; Gruntenko et al. 2005; Neckameyer and Weinstein 2005; Gruntenko et al. 2007; Rauschenbach et al. 2007; Gruntenko and Rauschenbach 2008; Bogomolova et al. 2009; Gruntenko et al. 2009; Panacek et al. 2011). Dopamine and octopamine regulate gonadotropin secretion and also melanisation of cuticle (Walter et al. 1996). Similarly, alteration in juvenile hormone (decrease in its degradation) and 20-hydroxyecdysone or 20HE (increased level due to change in ecdysteroid system) decrease the fertility in D. melanogaster (Rauschenbach et al. 1996; Hirashima et al. 2000). Heat stress can also bring about oocyte maturation delay, delay in vitelline membrane degradation, inhibit genes expression level of follicle cells responsible for the formation of yolk protein, and increase in a number of mature oocytes (Gruntenko et al. 2003). Various mechanisms through which NP toxicity can take place are summarized in figure (Figure 3).