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Host Defense and Parasite Evasion
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Pathogens entering host phagocytes are often destroyed by the generation of chemically reactive oxygen (ROS) and nitrogen (RNS) compounds (see Figure 4.15). Their survival is further hampered by the low pH and proteolytic enzymes found within the acidified vesicles of the endomembrane system. Certain intracellular protozoa, however, owe their success to their ability to avoid such destruction and thereby undermine an effective innate response. Clearly, if such intracellular parasites are able to thwart induced innate immunity in this way, many of the points made in previous sections regarding the initiation of an adaptive response become moot, allowing the parasite to establish a long-term, chronic infection. Both T. gondii and Trypanosoma cruzi, for example are capable of survival within the hostile, low pH environment of the macrophage phagolysosome. Various Leishmania species have a particularly noteworthy bag of tricks, allowing them to not only survive, but proliferate within host macrophages (Figure 4.24).
Structure, Function and Evolutionary Aspects of Mitochondria
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Puja Agarwal, Mehali Mitra, Sujit Roy
The presence of contact sites between the endomembrane system – mainly the endoplasmic reticulum (ER) – and mitochondria is necessary for the import of lipids into mitochondrial membranes and also the assembly of outer membrane β-barrel proteins (Dimmer and Rapaport, 2017; Ellenrieder et al., 2017). This contact sites are made by the four-subunit ERMES complex, which functions both as a lipid transfer complex and a tether (Dimmer and Rapaport, 2017; Ellenrieder et al., 2017). ERMES (Endoplasmic reticulum mitochondria endomembrane system) subunits share no known homology with the prokaryotic system, but it was likely present in Last Eukaryotic Common Ancestor (LECA), although it has been lost in major eukaryotic lineages like metazoans and green plants (Wideman and Gomez, 2016). But the loss of ERMES is compensated by the presence of an alternative tethers between the endomembrane system and mitochondria like EMC or vCLAMPs (Dimmer and Rapaport, 2017; Wideman and Gomez, 2016).
An Outbreak of Nontyphoid Salmonellosis in the Workplace
Published in Meera Chand, John Holton, Case Studies in Infection Control, 2018
NTS has adapted another pathogenicity island, Salmonella pathogenicity island 2 (SPI2), which allows this subspecies to invade macrophages. SPI2 codes for another type-III secretion system that provides up to 30 effector proteins, allowing NTS to replicate within a Salmonella-containing vacuole (SCV). The effector proteins work within the macrophage’s endomembrane system and cytoplasm. This mechanism allows for the extraintestinal spectrum of disease for NTS.
Intestinal phages interact with bacteria and are involved in human diseases
Published in Gut Microbes, 2022
Hannigan et al. (2018) analyzed 16S rRNA gene, whole shotgun metagenomic, and purified virus metagenomic sequencing of fecal samples from 30 healthy people, 30 patients with adenoma and 30 patients with CRC. The results showed that the cancer-associated virome consisted primarily of temperate bacteriophages that can indirectly induce cancer development by regulating the bacterial community composition.88 Moreover, phages can spread throughout sterile regions of bodies, including the blood, lymph, organs, and even the brain. Nguyen S et al. reported the rapid and directional transcytosis of diverse bacteriophages across confluent cell layers originating from the gut by incubating phage T4 with T84 (colon epithelial) cells and CaCo2 (colon epithelial) cells. Bacteriophages can access both the vesicular and cytosolic compartments of the eukaryotic cell, and transcytosed phages can traffic through the Golgi apparatus via the endomembrane system.89,90
Peptide-mediated drug delivery across the blood-brain barrier for targeting brain tumors
Published in Expert Opinion on Drug Delivery, 2019
Behzad Jafari, Mohammad M. Pourseif, Jaleh Barar, Mohammad A. Rafi, Yadollah Omidi
Cells can internalize particulates and macromolecules through phagocytosis and pinocytosis. Endocytosis that refers to a physiological mechanism, whereby cells internalize macromolecular biomolecules (<150 nm in diameter) and associated extracellular fluid from outside and via the endomembrane system. It works as a shuttle for the transportation of the captured molecules between the distinct membrane-enclosed vesicles, so-called vesicular trafficking [27]. Endocytosis of biomacromolecules by the BCECs can occur through (i) fluid-phase endocytosis (FPE), (ii) AME, and (iii) RME.
Bioinformatics analysis to identify action targets in NCI-N87 gastric cancer cells exposed to quercetin
Published in Pharmaceutical Biology, 2018
Yun Zeng, Zhengjie Shen, Wenzhe Gu, Mianhua Wu
Upregulated genes were mainly enriched within the apical plasma membrane (CC, P = 8.49E-03) in response to cAMP signaling (BP, P = 3.54E-09), had oxidoreductase activity (MF, P = 1.86E-04), and were involved in osteoclast differentiation (pathway, P = 3.76E-03) (Table 1). The top five functions and pathways for downregulated genes included regulation of BPs (BP, P = 1.45E-05) within the endomembrane system (CC, P = 1.75E-02), MFs (P = 1.10E-04), and gap junction pathway involvement (P = 3.01E-02) (Table 2).