Introduction: Background Material
Nassir H. Sabah in Neuromuscular Fundamentals, 2020
All living cells have a surrounding envelope referred to as the cell membrane, or plasma membrane. Animal cells are eukaryotic, that is, they have a well-developed nucleus and other membrane-bounded organelles, which are cell elements that perform some specialized functions. Figure 1.1 illustrates a typical eukaryotic cell and some of its organelles. The part of the cell that is outside the nucleus and bounded by the cell membrane is the cytoplasm. The cytosol, or intracellular fluid, is the liquid part of the cytoplasm, exclusive of organelles. It consists of a complex mixture of substances that are dissolved or suspended in water. The cell membrane is discussed in considerable detail in Sections 2.1 and 2.2. The following cell organelles are particularly relevant for our purposes.
From cells to systems
Nick Draper, Helen Marshall in Exercise Physiology, 2014
Cells typically have three components: the cell or plasma membrane, the nucleus and the remaining contents of the cell known as the cytoplasm (see Figure 3.2). The plasma membrane is a very thin structure that encloses every cell and keeps it separate from its surrounding environment. The nucleus, normally the largest single unit in the cell, contains the DNA, the genetic blueprint for controlling the operations of the cell, and the ribonucleic acid (RNA), a single stranded version of DNA which, amongst other things, controls protein synthesis within the cell. The cytoplasm comprises the inside of the cell except for the nucleus. It is made up of a gel-like substance, cytosol, which houses and protects nine main sorts of small structures called organelles. These organelles serve a variety of roles for the cell. An illustration of one such organelle, a mitochondrion, is provided in Figure 3.4. Mitochondria are the power plants of many cells and are responsible for producing about 90% of human energy.
Finding a Target
Nathan Keighley in Miraculous Medicines and the Chemistry of Drug Design, 2020
Organelles perform different roles in the cell. The mitochondria are responsible for energy generation. Through the process of respiration, they manufacture adenosine triphosphate (ATP); a source of chemical energy. Modification of selected molecules is undertaken at the Golgi apparatus and/or the endoplasmic reticulum. Molecules manufactured by the cell, or assimilated from outside, may need to be changed to make them suitable for a given biochemical process. The Golgi apparatus and endoplasmic reticulum are the organelles with the capacity to perform this role. The nucleus, as previously mentioned, is where DNA is contained and is the control centre for the cell. Having a porous membrane enables passage of selected molecules to facilitate communication between the nucleus and the rest of the cell to ensure that instructions are received for the essential biochemical process of the cell to continue functioning without error.
A simple geometric method for 3D morphology reconstruction of a cell based on two orthogonal phase images
Published in Computer Assisted Surgery, 2019
Yawei Wang, Hao Han, Lei Wang, Jingrong Liao, Bing Xie, Ying Ji, Yuanyuan Xu
A cell is the basic unit of an organism structure. As for individual cell, the morphological characteristic as well as the internal composition, plays a crucial role in its health status, function and activity. Most of cells are colorless and transparent, the traditional optical microscope fails to image them because of the inadequate contrast. Quantitative phase microscopy (QPM) is a solution to this engineering roadblock. Since it used the cellular refractive index (RI) as an endogenous contrast, it is a noninvasive and nondestructive imaging tool. In recent years, various QPM [1–6] techniques have been proposed with high accuracy and high speed. These techniques are mainly applied to the homogeneous cell, since there is a linear relationship between its phase and the axial thickness. However, for a heterogeneous cell, we cannot obtain its morphological information from the phase. Although we combine other technique, such as the confocal one, only the average RI or the physical thickness along the light transmission direction is obtained. Unfortunately, the axis physical thickness distribution of phase object cannot reveal the 3D structure information correctly.
Combination of oxytetracycline and quinocetone synergistically induces hepatotoxicity via generation of reactive oxygen species and activation of mitochondrial pathway
Published in Toxicology Mechanisms and Methods, 2022
Lirui Hou, Fang Liu, Chong Zhao, Lihong Fan, Hongbo Hu, Shutao Yin
This hypothesis was examined in the present study using both cell cultures and animal models. Results demonstrated that a synergistic cytotoxicity was induced by the combination treatment in the cell culture studies. Moreover, combined exposure led to increased liver toxicity in mice. Studies have shown that ROS generation plays a critical role in mitochondrial pathway regulation and several literatures have reported that OTC can stimulate ROS accumulation (Yang et al. 2017, 2018). Therefore, we evaluated whether the OTC/QCT-induced changes in the mitochondrial pathway were associated with ROS generation (Park et al. 2018; Yang et al. 2018). In Figure 4, cellular ROS levels were measured by flow cytometry and the results showed that ROS generation was indeed significantly augmented in response to combination exposure, in comparison with responses to each single substance treatment. Furthermore, the inhibition of oxidative stress by antioxidant NAC nearly completely abolished this combined cytotoxicity. Together, these data confirm the involvement of enhanced ROS generation in combination-induced synergistic cytotoxicity.
Progress in tumour-targeted drug delivery based on cell-penetrating peptides
Published in Journal of Drug Targeting, 2022
Xinru Kong, Jiangkang Xu, Xiaoye Yang, Yujia Zhai, Jianbo Ji, Guangxi Zhai
The nucleus is the control centre of the cell and is one of the most targeted organelles in cancer nanomedicine. Nuclear localised CPPs are usually composed of a nuclear localisation sequence (NLS) and a transmembrane sequence. Common NLSs include TAT, SV40 large T antigens, and SRY proteins [84]. Zhang et al. [10] reported an NF-κB inhibitor peptide, CB5005, which consists of 21 amino acids and can be divided into two cascade fragments: the membrane permeation sequence (CB5005M), and the NLS (CB5005N) (Figure 5(A)). TAT seems to have nuclear targeting ability. Pang et al. [85] improved PTT treatment by delivering iron oxide nanoparticles (IONPs) to the nucleus, using TAT to functionalise IONPs to achieve effective nuclear targeting, and using fluorescent dyes for real-time tracking. Approximately 122 µg iron per milligram protein accumulated in the nucleus, which was 45 times higher than that of unmodified TAT.