Melanose multicêntrica em frango de corte: relato de caso / Multicentric melanosis in broiler: case report

Melanoblastos podem migrar de forma errática durante a embriogênese, gerando um quadro conhecido como melanose. São raros os estudos envolvendo melanose com acometimento múltiplo dos órgãos. Objetivou-se descrever um caso de melanose multicêntrica em frango de corte que gerou condenação do animal ao abate. Foram encaminhadas ao Laboratório de Patologia Animal da Universidade Federal do Espírito Santo para avaliação histopatológica amostras de diversos órgãos de uma ave de corte da linhagem Cobb de 48-49 dias de idade. Esse animal foi condenado na linha de inspeção por apresentar áreas multifocais enegrecidas. Ao exame microscópico, observou-se melanina multifocal variando de moderada a intensa quantidade em todos os órgãos acometidos com lesões enegrecidas na macroscopia. As áreas pigmentadas foram negativas para a coloração especial de azul da Prússia e não foram encontradas células neoplásicas. A pigmentação da pele em aves comercializadas no Ocidente é rara, pois a característica de pele clara foi selecionada por meio de melhoramento genético, mas pouco se sabe sobre quais mutações desencadeiam melanose nas linhagens selecionadas para não apresentar pigmentação. A ave apresentou melanose multicêntrica e tal alteração não compromete a função dos órgãos acometidos nem representa risco para a saúde humana, no entanto, devido ao aspecto macroscópico, os órgãos que apresentam tal lesão foram condenados para consumo humano.(AU)

Melanoblasts can enter an erratic migratory pathway during embryogenesis and it creates a clinical condition known as melanosis. Studies involving melanosis in multiple organs are rare. The aim of this paper is to describe a case of multicentric melanosis in a broiler resulting in animal condemnation at slaughter. Samples from diverse organs originating from a Cobb broiler, 48-49 days of age, were sent to Laboratório de Patologia Animal from Universidade Federal do Espírito Santo for histopathological avaliation. This animal was condemned in line inspection due to multifocal black areas of pigmentation. At microcopic avaliation, multifocal melanin in moderate-intense amount in all the organs stricken with macroscopic black lesions was noted. Sections of pigmented areas were negative for Prussian Blue and no neoplasic cells were found. Pigmentation of the skin in a broiler from the Ocident is rare because the white/yellow skin was selected through genetic enhancement, but there is some data about which mutations unleash melanosis in lineages selected to not have pigmentation. The broiler had multicentric melanosis and this alteration doesn't change functional activity of the stricken organs and doesn't represent any risk for human health, but the organs with this lesion were condemned for human consumption due to their macroscopic appearance.(AU)

In vitro observation of haemolymph melanization and melanin-related biosynthesis enzyme genes in silkworm, Bombyx mori / 生物工程学报

The observation statistics suggested that the haemolymph melanization speed of larvae became fast and the growth inhibition of Escherichia coli was strong as the quantities of feeding on mulberry leaves increased. The RT-PCR result showed that the mRNA expressions of melanin biosynthesis enzyme BmTan, BmPo-1, BmYellow-f and BmDdc were high in the haemolyph of 5 L 3 d larvae. The qPCR analysis showed Bmtan, Bmddc, Bmyellow, Bmebony and Bmblack, especially Bmddc expression were significantly higher in black disease larvae than in normal larvae. Compared with control, Ddc inhibitors drastically inhibited the lipopolysaccharide-induced haemolymph melanization. In addition, the content of Dopa and Dopamine markedly rose after E. coli injection. These indicated that haemolymph melanization was linked to immune defenses and Bmddc may play a role in melanization response of haemolymph immune in silkworm.

On the reliability of a simple method for scoring phenotypes to estimate heritability: a case study with pupal color in Heliconius erato phyllis, Fabricius 1775 (Lepidoptera, Nymphalidae)

In this paper, two methods for assessing the degree of melanization of pupal exuviae from the butterfly Heliconius erato phyllis, Fabricius 1775 (Lepidoptera, Nymphalidae, Heliconiini) are compared. In the first method, which was qualitative, the exuviae were classified by scoring the degree of melanization, whereas in the second method, which was quantitative, the exuviae were classified by optical density followed by analysis with appropriate software. The heritability (h2 ) of the degree of melanization was estimated by regression and analysis of variance. The estimates of h 2 were similar with both methods, indicating that the qualitative method could be particularly suitable for field work. The low estimates obtained for heritability may have resulted from the small sample size (n = 7-18 broods, including the parents) or from the allocation-priority hypothesis in which pupal color would be a lower priority trait compared to morphological traits and adequate larval development.

Effect of L - tyrosine on Proliferation and Melanization in Cultured Normal Human Melanocytes / 대한피부과학회지

BACKGROUND: The biosynthesis of melanin is initiated by the enzymatic oxidation of L-tyrosine to L-dopa by tyrosinase. Some precursors of melanin are cytotoxic, and melanoma cells are killed as a risk of exposare to excess tyrosine or dopa in the culture medium. However, there have been few observations of the effects of L-tyrosine on cultured normal human melanocyte. OBJECTIVE: In order to investigate whether exogenous tyrosine induces cytotoxicity in cultured normal human melanocytes as in melanoma cells, we examined the effects of L-tyrosine on proliferation and melanization in normal human melanocytes. METHODS: A melanocyte culture was produced with a modified TIC medium. L-tyrosine was added to the culture medium, 100, 200, 400, and 800uM. After 2 days of incubation, the proliferation was measured by methylthiazol tetrazolium(MTT) assay and sulforhodamine B(SRB) assay. The melanin contenis were also measured by the modified Whittaker's method. RESULTS: On MTT assay, the proliferation of melanocytes had been stirnulated significantly (p< 0.05) in all L-tyrosine added groups. On SRB assay, the proliferation of melanocytes had heen stimulated significantly (p<005) in 200, 400, 800uM of L-tyrosine added groups. The melanin contents had increased in all L-tyrosine added groups, and had increased significantly (p<0.05) in 400uM of L-tyrosine added group. CONCLUSION: L-tyrosine is not toxic to normal melanocytes, It stimulates the proliferation and melnization of cultured normal human melanocytes.

Effect of L - tyrosine on Proliferation and Melanization in Cultured Normal Human Melanocytes / 대한피부과학회지

BACKGROUND: The biosynthesis of melanin is initiated by the enzymatic oxidation of L-tyrosine to L-dopa by tyrosinase. Some precursors of melanin are cytotoxic, and melanoma cells are killed as a risk of exposare to excess tyrosine or dopa in the culture medium. However, there have been few observations of the effects of L-tyrosine on cultured normal human melanocyte. OBJECTIVE: In order to investigate whether exogenous tyrosine induces cytotoxicity in cultured normal human melanocytes as in melanoma cells, we examined the effects of L-tyrosine on proliferation and melanization in normal human melanocytes. METHODS: A melanocyte culture was produced with a modified TIC medium. L-tyrosine was added to the culture medium, 100, 200, 400, and 800uM. After 2 days of incubation, the proliferation was measured by methylthiazol tetrazolium(MTT) assay and sulforhodamine B(SRB) assay. The melanin contenis were also measured by the modified Whittaker's method. RESULTS: On MTT assay, the proliferation of melanocytes had been stirnulated significantly (p< 0.05) in all L-tyrosine added groups. On SRB assay, the proliferation of melanocytes had heen stimulated significantly (p<005) in 200, 400, 800uM of L-tyrosine added groups. The melanin contents had increased in all L-tyrosine added groups, and had increased significantly (p<0.05) in 400uM of L-tyrosine added group. CONCLUSION: L-tyrosine is not toxic to normal melanocytes, It stimulates the proliferation and melnization of cultured normal human melanocytes.

The effects of UVA and UVB on proliferation and melanization in SK 23 melanoma cell lines / 대한피부과학회지

BACKGROUND: The visible cutaneous pigmentary response to ultraviolet A(UVA) is immediate, whereas ultraviolet B(UVB)-induced pigmentation appears after a delay of several days. However, some investigators reported that UVA also can induce delayed taniing. OBJECTIVE: In order to determine whether the pigmentation induceil by UVA irradiation is accompanied by melanocytes responses which are the same or different from those following a UVB-indueed tan, we irraiated malignant melanoma cells to UVA or UVB. METHOD: On the 7th day after irradiation of UVA or UVB, we exa nined the cell counts and the melanin content of control and experimental groups. RESULTS: Although a dose of 10 J/cm decreased the number of manignant melanoma cells, there was no significant difference between the control and UVA-exposure griiups. But there was a significant decrease after UVB-exposun. UVB-exposure groups showed a significant increase of melanin cortent. A dose of 10 J/cm of UVA also induced a significant increase of melanin content. CONCLUSIONS: The data suggest that UVA at a clinically relevant dose has a significant effect on human melanocytes. So, UVA very likely plays a role in the increased, melanization associated with delayed tanning.

The effects of hemocytes on normal and degenerated oocysts of P.yoelii in mosquitoes and on melanization of oocysts / 第三军医大学学报

Anopheles Stephensi,infected with Plasmodium yoelii.was fed on 10% sucrose solution containing 1%.difluoromethylornothine(DFMO)to induce the degeneration of its oocysts.On the 11th day after infection,the effects of hemocytes on the normal and degenerated oocysts were observed wtih transmission electron microscopy.In the control group.no hemacytes could be found around the normally-developed oocysts except those degenerated ones.In the DFMO group,all the oocysts underwent degeneration in various degrees and some of them were melanized.All the oocysts were attached by one or more hemocytes which belonged to the category of granulo-cytes morphologically.There were many granules with microtubular construction in the cytoplasm of the hemocytes and in the spaces between a hemocyte and an oocyst.The findings indicate that the degeneration of oocysts can exert a taxic effect on hemocytes and the latter may release the granules and possibly other substances to result in the encapsulation and melanization of the oocysts.