Melanin In Bloom: My Journal

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Double KL (2006). "Functional effects of neuromelanin and synthetic melanin in model systems". J Neural Transm. 113 (6): 751–756. doi: 10.1007/s00702-006-0450-5. PMID 16755379. S2CID 23096297.

We attempted to use the standard dye propidium iodide (PI) to validate that GFP-negative cells within nodules are dead. Surprisingly, PI staining did not stain nodule-encapsulated yeast cells, although there was staining in some of the hemocytes that surrounded the yeast cells, and the external periphery of the nodules (Fig. 1f). The absence of PI staining of the fungi is likely due to inability of the dye to penetrate the nodule fully. Following infection of G. mellonella larvae, we found fewer GFP-positive melanin-encapsulated fungal cells within nodules of infected larvae compared to GFP-positive non-melanin-encapsulated fungal cells at both room temperature and at 30 °C at 24 and 72 h post-infection (Fig. 1c, d). Using the counts of GFP positivity of fungi within nodules, he non-melanin-encapsulated fungi had a survival rate of approximately 22, 33, 59, and 38% for the room temperature 24 and 72 h and the 30 °C at 24 and 72 h conditions, respectively (Fig. 1d). The melanin-encapsulated fungi had a survival rate of approximately 6, 10, 21, and 16% for the room temperature 24 and 72 h and the 30 °C at 24 and 72 h conditions, respectively (Fig. 1d). These data show that melanin-encapsulation was thus associated with approximately 21, 34, 92, and 35% greater amount of fungal death at the temperatures and times tested. This indicates that melanization contributes to a significant amount of fungal death during infection but is not the only nor predominant mechanism by which fungal cells are killed. Additional causes of fungal death in this model may include antimicrobial peptides and respiratory bursts, as previously described 3. Melanin produced by C. neoformans in culture did not quench or obscure the GFP fluorescence, as determined by imaging melanized versus non-melanized C. neoformans H99-GFP (Supplementary Fig. 1c, d). Therefore, these results suggests that the immune melanization reaction resulted in fewer GFP-positive cells, which indicated that melanization kills C. neoformans in vivo during infections of G. mellonella. When you spend time out in the sun, your body produces more melanin. The substance absorbs light from UV rays and redistributes it toward the upper layers of skin. It also protects the genetic material stored in your cells by keeping out harmful UV rays.Early humans evolved to have dark skin color around 1.2million years ago, as an adaptation to a loss of body hair that increased the effects of UV radiation. Before the development of hairlessness, early humans had reasonably light skin underneath their fur, similar to that found in other primates. [63] The most recent scientific evidence indicates that anatomically modern humans evolved in Africa between 200,000 and 100,000 years ago, [64] and then populated the rest of the world through one migration between 80,000 and 50,000 years ago, in some areas interbreeding with certain archaic human species ( Neanderthals, Denisovans, and possibly others). [65] It seems likely that the first modern humans had relatively large numbers of eumelanin-producing melanocytes, producing darker skin similar to the indigenous people of Africa today. As some of these original people migrated and settled in areas of Asia and Europe, the selective pressure for eumelanin production decreased in climates where radiation from the sun was less intense. This eventually produced the current range of human skin color. Of the two common gene variants known to be associated with pale human skin, Mc1r does not appear to have undergone positive selection, [66] while SLC24A5 has undergone positive selection. [67] Effects [ edit ] In the human skin, melanogenesis is initiated by exposure to UV radiation, causing the skin to darken. Eumelanin is an effective absorbent of light; the pigment is able to dissipate over 99.9% of absorbed UV radiation. [3] Because of this property, eumelanin is thought to protect skin cells from UVA and UVB radiation damage, reducing the risk of folate depletion and dermal degradation. Exposure to UV radiation is associated with increased risk of malignant melanoma, a cancer of melanocytes (melanin cells). Studies have shown a lower incidence for skin cancer in individuals with more concentrated melanin, i.e. darker skin tone. [4] Humans [ edit ] Albinism occurs when melanocytes produce little melanin. This albino girl is from Papua New Guinea.

According to the Wisconsin Horticulture, their precise taxonomy is difficult to pinpoint because the plant has been naturalized throughout the Americas over centuries. However, it is often mentioned as a nuisance and called jimsonweed or mistakenly identified as Brugmansia (also known as the Angel Trumpet). How can you tell? Datura flowers reach skyward while Angel Trumpet blooms face down. Bonser, Richard H. C. (1995). "Melanin and the Abrasion Resistance of Feathers". Condor. 97 (2): 590–591. doi: 10.2307/1369048. JSTOR 1369048. Mark Heiden (8 July 2020). "New biomaterial could shield against harmful radiation". Northwestern University . Retrieved 29 January 2023. a b Nenoi, M; Wang, B; Vares, G (12 June 2014). "In vivo radioadaptive response". Toxicology. Sage. 34 (3): 272–283. doi: 10.1177/0960327114537537. ISSN 0960-3271. PMC 4442823. PMID 24925363.

Materials and Methods

Dadachova E, Bryan RA, Huang X, etal. (2007). "Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi". PLOS ONE. 2 (5): e457. Bibcode: 2007PLoSO...2..457D. doi: 10.1371/journal.pone.0000457. PMC 1866175. PMID 17520016. Statistical tests were performed using GraphPad Prism Version 8. All error bars represent the mean with 95% Confidence Interval with the exceptions of the ratio comparison of melanization induced by H99 versus lac1∆ where the error bars represent the ±Standard Deviation from the mean, and the size comparison of in situ nodules where the error bars represent the 95% Confidence Interval of the median. To determine the effect of melanin-encapsulation on fungal viability within nodules, we performed a Chi-Squared analysis for each timepoint and temperature condition tested. The Chi-square table was set up with melanin-encapsulated and non-encapsulated on one side of the contingency table and GFP-positive and GFP-negative on the other. The ratio comparison of melanization induced by H99 versus lac1∆ was analyzed using a one sample t-test with comparisons to the theoretical value of 1, which would indicate no difference between the H99-induced melanization and lac1∆ -induced melanization. The size comparison of in situ nodules was performed using a two-tailed non-parametric Mann–Whitney Test comparing the particles from the uninfected versus infected groups. The comparison of the time it takes for the melanin-encapsulated versus non-encapsulated to escape melanization was done using an unpaired two-tailed t-test. The linear regression showing the relationship between CFUs and pigmentation of the hemolymph in vitro was performed using a simple linear regression, with the dotted lines representative of the 95% Confidence Intervals. Non-quantified data, such as microscopy images, were performed in replicates and representative images are shown, as noted in the figure legend. Reporting summary

Brenner M, Hearing VJ (2008). "The protective role of melanin against UV damage in human skin". Photochemistry and Photobiology. 84 (3): 539–49. doi: 10.1111/j.1751-1097.2007.00226.x. PMC 2671032. PMID 18435612. The research done by Sarna's team proved that heavily pigmented melanoma cells have Young's modulus about 4.93 kPa, when in non-pigmented ones it was only 0.98 kPa. [74] In another experiment they found that elasticity of melanoma cells is important for its metastasis and growth: non-pigmented tumors were bigger than pigmented and it was much easier for them to spread. They shown that there are both pigmented and non-pigmented cells in melanoma tumors, so that they can both be drug-resistant and metastatic. [74] Selenomelanin and possible use against X-ray radiation [ edit ]Rodríguez‐Martínez, Sol; Galván, Ismael (2020). "Juvenile pheomelanin-based plumage coloration has evolved more frequently in carnivorous species". Ibis. 162 (1): 238–244. doi: 10.1111/ibi.12770. hdl: 10261/207451. ISSN 1474-919X. S2CID 202018215.

Barillas-Mury, C. CLIP proteases and Plasmodium melanization in Anopheles gambiae. Trends Parasitol. 23, 297–299 (2007). A Single Migration From Africa Populated the World, Studies Find". The New York Times. 22 September 2016.Lu, Z. et al. Multifunctional role of a fungal pathogen-secreted laccase 2 in evasion of insect immune defense. Environ. Microbiol. 23, 1256–1274 (2021). Jablonski, Nina G.; Chaplin, George (11 May 2010). "Human skin pigmentation as an adaptation to UV radiation". Proceedings of the National Academy of Sciences. 107 (Supplement 2): 8962–8968. Bibcode: 2010PNAS..107.8962J. doi: 10.1073/pnas.0914628107. PMC 3024016. PMID 20445093. Mouchet, Sébastien R; Deparis, Olivier (2021), Natural Photonics and Bioinspiration (1sted.), Artech House, ISBN 978-163-081-797-8 Melanin produced by plants are sometimes referred to as 'catechol melanins' as they can yield catechol on alkali fusion. It is commonly seen in the enzymatic browning of fruits such as bananas. Chestnut shell melanin can be used as an antioxidant and coloring agent. [45] Biosynthesis involves the oxidation of indole-5,6-quinone by the tyrosinase type polyphenol oxidase from tyrosine and catecholamines leading to the formation of catechol melanin. Despite this many plants contain compounds which inhibit the production of melanins. [46] Interpretation as a single monomer [ edit ] Blooming artifact is a susceptibility artifact encountered on some MRI sequences in the presence of paramagnetic substances that affect the local magnetic milieux. Although it is an artifact, it may be deliberately exploited to improve detection of certain small lesions, much as the T1 shortening effects of low concentration g adolinium are used to detect contrast enhancement.