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Introduction to Cells, DNA, and Viruses
Published in Patricia G. Melloy, Viruses and Society, 2023
If we return to the central dogma for a moment, it is important to note that all cells obey the central dogma, but viruses do not. This became completely clear when the first viruses were discovered that did not have a DNA-based genome, and the central dogma had to be revisited because of these discoveries (Baltimore 1970; Temin and Mizutami 1970). Viruses can house their genetic material in the form of either DNA or RNA, single-stranded or double-stranded. There are actually many RNA viruses. A eukaryotic cell will carry its genetic material in the form of double-stranded DNA in the nucleus and make a single-stranded messenger RNA copy of any genes that are expressed. Viruses evolved to consist of all different kinds of genomes, but in the end, each template is adapted or converted in some way to fit in almost seamlessly to use the eukaryotic host cell’s transcriptional and translational mechanisms to make its necessary viral proteins and copy its genome. If the viral genome can somehow be converted to an mRNA transcript to be read by the host cell’s ribosomes, the virus can reproduce in that cell. In addition, because viruses are using the cell’s machinery, even though a virus may start out with different genetic material, viruses still follow the genetic code language of cells where mRNA is translated into certain amino acids that make up proteins (Lostroh 2019).
Bacteria
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Prokaryotic cells are fundamentally different from eukaryotic cells (Table 15.2). Structure is an important consideration because of the involvement of several structural components as factors of virulence, i.e., the ability of the microbe to cause disease. Figure 15.2 is an idealized schematic drawing of a prokaryotic cell showing structural components. It must be emphasized, however, that not all of the components shown are always present in a single species of bacteria. Keep in mind that all bacterial diseases are interactions between prokaryotic and eukaryotic cells.
Fungi and Water
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Fungi including mushrooms, molds, and yeasts are eukaryotic organisms as vegetable or animal species, but are classified as a separate kingdom because fungal cell walls contain rigid chitin and glucans that are not found in animal, vegetal, or bacterial species (1–8). Eukaryotic cells are cells that contain a nucleus and other organelles enclosed within membranes. In other words, the fungal kingdom comprises a hyper diverse clade of heterotrophic eukaryotes characterized by the presence of a chitinous cell wall, the loss of phagotrophic capabilities, and cell organizations that range from completely unicellular monopolar organisms to highly complex syncytial filaments (containing several nuclei) that may form macroscopic structures (8). Mushrooms like morels, button mushroom, and puffballs are macroscopic multicellular fungi, while molds are a large group of microscopic multicellular fungi. Molds are characterized by filamentous forms named hyphae. Many fungi occur not as hyphae but as unicellular forms called yeasts, which are invisible to the naked eye and reproduce by budding (2–4).
Identification of Rab7 as an autophagy marker: potential therapeutic approaches and the effect of Qi Teng Xiao Zhuo granule in chronic glomerulonephritis
Published in Pharmaceutical Biology, 2023
Xiujuan Qin, Huiyu Chen, Xiaoli Zhu, Xianjin Xu, Jiarong Gao
Mitochondria are important eukaryotic cell organelles; they produce ATP via oxidative phosphorylation and provide 95% of the cell’s energy requirements. They are also involved in metabolic signal transduction, inflammation, and apoptosis regulation. The kidney is rich in mitochondria, which play a key role in its function, and mitochondrial damage and dysfunction are major factors in many chronic and acute kidney diseases (Tang et al. 2021). Maintaining mitochondrial homeostasis and metabolic balance is crucial for kidney function (Bhargava and Schnellmann 2017). When mitochondrial damage and dysfunction occur, mitophagy is induced to maintain cell homeostasis, removing damaged or excess mitochondria (Su et al. 2023). Transmission electron microscopy showed that abnormal mitochondrial cristae and decreased autophagosomes were apparent in the model group. Interestingly, we also found that mitochondrial damage was reduced after QTXZG treatment.
Protective role of PERK-eIF2α-ATF4 pathway in chronic renal failure induced injury of rat hippocampal neurons
Published in International Journal of Neuroscience, 2023
Qi Chen, Jingjing Min, Ming Zhu, Zhanqin Shi, Pingping Chen, Lingyan Ren, Xiaoyi Wang
The endoplasmic reticulum is one of the most important organelles in eukaryotic cells. It is not only the site for protein translation and synthesis as well as calcium ion storage, but also a participant in the transmission and processing of various cell signals. In addition, one of the major functions of the endoplasmic reticulum is to serve as a site for synthesizing secretory and integral membrane proteins.5,6 When cells are stimulated by hypoxia, an imbalance of calcium ions or a change in their concentration occurs in the internal environment, accompanied with the accumulation of some unfolded proteins in the endoplasmic reticulum, resulting in an imbalance between the structure and function of the endoplasmic reticulum. At this time, the corresponding signal pathway is activated to further trigger the endoplasmic reticulum stress (ERS) response.7 Unfolded protein response activation can be triggered in the following three ways: (1) inhibition of protein translation to prevent the production of more folded proteins; (2) induction of the folding of unfolded proteins by the endoplasmic reticulum chaperone; (3) activation of endoplasmic reticulum associated degradation pathways to remove unfolded proteins accumulated in the endoplasmic reticulum.8 However, under prolonged or severe stress, the unfolded protein response initiates programmed cell death.
Bacteria and cells as alternative nano-carriers for biomedical applications
Published in Expert Opinion on Drug Delivery, 2022
Rafaela García-Álvarez, María Vallet-Regí
Bacteria and cells have been utilized for medical purposes for a very long time. The interesting properties and behavior they exhibit as a function of cell or bacteria type are remarkable characteristics that make them a relevant alternative for biomedical applications, such as cancer therapy or as drug delivery platforms. On the one hand, bacteria possess intrinsic characteristics such as self-propulsion, bacterial taxis, or stimuli-responsive capacities. In addition, they can be used for internalization of genetic material through batofection, and they can be emptied and employed in the form of bacteria ghosts as drug delivery platforms. On the other hand, eukaryotic cells also have a long history of medical applications, with examples as common nowadays, such as blood transfusion or skin transplants. Among the numerous types of cells existing in our organisms, a variety of them display remarkable properties like long-term circulation or tumor-targeting nature, which makes them useful for a potential use in biomedical applications. Moreover, in a similar way to bacterial ghosts, cell membranes, exosomes, and lipid mixtures are used as envelopes for bioactive molecules or other therapeutic agents.