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Factors Affecting the Microflora of the Lower Genital Tract of Healthy Women
Published in Michael J. Hill, Philip D. Marsh, Human Microbial Ecology, 2020
Lysozyme, which hydrolyzes β-1,4 linkages of peptidoglycan resulting in osmotic lysis and formation of spheroplasts, has been found in genital secretions.102 Lactoferrin is an iron-binding protein which may also be present. The rate of bacterial growth may be affected if there is competition with lactoferrin for iron, an essential element.103 Variation in the clinical manifestations of gonococcal infection has been attributed to differences in the ability of gonococcal strains to compete with the host for iron. Strains that cause uncomplicated mucosal infection are reported to have a reduced capacity to obtain iron in comparison with strains that cause disseminated infection.104 Gonococcal strains that require arginine, hypoxanthine, and uracil (AHU) for growth have been reported to have a decreased ability to acquire iron in comparison with other strains that are associated with mucosal infection. It has been suggested that this explains the tendency for AHU strains to cause asymptomatic mucosal infection.105 Strains of N. gonorrhoeae with this auxotype have been associated with disseminated infection which would appear to be inconsistent with this theory. However, infection with these strains has been linked with menses when iron may be provided in the form of haemin and transferrin which would remove the competition with lactoferrin.
Effect of Transport on Distribution of Radioions and Radiometabolites
Published in Lelio G. Colombetti, Biological Transport of Radiotracers, 2020
The exact mechanism facilitating the transfer of 67Ga from the plasma to the cell is still unknown.120 However, the association of 67Ga with transferrin is known.112,121,122 Tissue-bound 67Ga is also associated with the iron-binding proteins ferritin and transferrin,112,118,123 and 67Ga is found primarily in microvesicles of tumor cells and lysosomes of normal liver cells.116
Pregnancy-Related Proteins Detected by Their Biological Activities
Published in Gábor N. Than, Hans Bohn, Dénes G. Szabó, Advances in Pregnancy-Related Protein Research, 2020
Lactoferrin is an iron-binding protein which occurs in higher concentrations in colostrum and milk. It has the electrophoretic mobility of a γ-globulin, a molecular weight of 82,600 and specifically binds two ferric atoms per molecule. It differs from serum transferrin in its immunological properties, conformation, and localization of the iron-binding sites; the binding constant of iron for human milk lactoferrin is nearly 300 times greater than that for serum transferrin. The concentration of lactoferrin in colostrum amounts to about 400 mg/dl. Despite its designation, lactoferrin is not specific to milk. It is secreted not only by the mammary glands, but also by the lacrimal, bronchial, and salivary glands, as well as the mucosal surface of the endometrium and seminal versicles (reviewed by Cejka).197 Lactoferrin also has been detected by immunochemical methods in protein fractions of the human placenta solubilized with 6 M urea. In the placenta, this protein thus appears to be bound to membranes.198
SARS-CoV-2 Infection Dysregulates Host Iron (Fe)-Redox Homeostasis (Fe-R-H): Role of Fe-Redox Regulators, Ferroptosis Inhibitors, Anticoagulants, and Iron-Chelators in COVID-19 Control
Published in Journal of Dietary Supplements, 2023
Sreus A.G. Naidu, Roger A. Clemens, A. Satyanarayan Naidu
LF regulates both pro-inflammatory and anti-inflammatory responses (171); thereby could prevent viral insult-induced ‘cytokine storm’ (186). The anti-inflammatory activity of LF is associated with its ability to enter host cell nucleus and inhibit the synthesis of proinflammatory cytokine genes. Both IL-6 and IL-1β levels are elevated during inflammation due to up-regulation of cytosolic ferritin, down-regulation of FPN, membrane-bound ceruloplasmin, and TfR1 (172). This inflammatory response results in intracellular iron overload that may increase host susceptibility to infections and manifest as blood iron deficiency (i.e. anemia). Establishing the Fe-R-H by rebalancing iron levels between tissues/secretions and blood anemia could be critical during inflammation. Iron-binding proteins such as LF, TF, and ferritin play a pivotal role in human ferrokinetics (187). LF is an effective down-regulator of both IL-6 and IL-1β, as well as in preventing the activation of FPN, membrane-bound ceruloplasmin, cytosolic ferritin, and TfR1 in macrophages (52, 188). LF also activates plasminogen that regulates coagulation cascade and antithrombotic activity, a common clinical condition observed in SARS-CoV-2 infection (189,190).
High iron-mediated increased oral fungal burden, oral-to-gut transmission, and changes to pathogenicity of Candida albicans in oropharyngeal candidiasis
Published in Journal of Oral Microbiology, 2022
Aparna Tripathi, Anubhav Nahar, Rishabh Sharma, Trevor Kanaskie, Nezar Al-Hebshi, Sumant Puri
Candida albicans is the most common commensal fungus in healthy individuals, and the primary causative agent of oropharyngeal candidiasis (OPC) in the immunocompromised [1]. Changes in the host-specific environment, including alterations in iron levels, can cause variations in the C. albicans burden and affect its virulence [2]. Iron is an essential nutrient that can be sourced by oral microbes from inorganic iron (in saliva), heme-bound iron (in crevicular fluid and non-vegetarian diet), and non-heme iron (in vegetarian diet); or can be sequestered from iron-binding proteins like transferrin, lactoferrin, and hemoglobin. Lack of a divalent metal transporter in the oral epithelium, host-related factors like iron-rich diet, and abundance of acid-producing bacteria that increases iron bio-availability by reducing environmental pH [3], can potentially make the oral environment particularly iron-rich.
Selected application of peptide molecules as pharmaceutical agents and in cosmeceuticals
Published in Expert Opinion on Biological Therapy, 2019
Manica Negahdaripour, Hajar Owji, Mahboobeh Eslami, Mozhdeh Zamani, Bahareh Vakili, Soudabeh Sabetian, Navid Nezafat, Younes Ghasemi
In animals, AMPs are one of the first lines of innate immune system against pathogens. It is believed that they protect tissues from airborne pathogens [85]. Defensins, as the first animal AMPs with bactericidal activity, were isolated from rabbit leukocytes. They are the most researched animal AMPs and have been categorized into α and β-defensins [86]. Human leukocytes can also produce AMPs such as α-defensins and cathelicidin LL-37 in their lysosomes [87,88]. Indolicidins and cathelicidins are antimicrobial peptides that have been isolated from neutrophils [86]. Lactoferrins, also known as lactotransferrins, are iron-binding proteins, which are found in various exocrine secretions such as milk, tears, saliva, and urine. They have shown antimicrobial activity against a wide range of pathogens [89,90]. Bombinins, the antimicrobial and hemolytic peptides from epithelia [91], and bombinin-like peptides from the skin [92] were also proposed as AMPs due to their antimicrobial activities. Furthermore, dermaseptin-1 from skin of the frog is an AMP with a potent antimicrobial activity against multiple Leishmania species [93].