- ArtículoAcceso AbiertoCorrosión localizada del acero inoxidable austenítico en medio de cultivo celular y evaluación de la citotoxicidad de los iones liberados(2021)El acero inoxidable austenítico ASTM F745 ha sido sometido a corrosión localizada en medio de cultivo celular y solución acuosa de NaCl, cuyas concentraciones de cloruro fueron 4413,2 mg L-1 y 5423,1 mg L-1, respectivamente. Se ha observado que la susceptibilidad a la corrosión localizada fue menor en el medio de cultivo debido a su menor contenido de cloruros. El Fe fue el metal más liberado en ambos medios durante el proceso de corrosión. Las concentraciones fueron 0,570 mg L-1 en la solución acuosa de NaCl y 0,480 mg L-1 en el medio de cultivo. Las concentraciones de Cr y Mo fueron similares en ambos medios, habiendo sido 0,040 mg L-1 y 0,010 mg L-1, respectivamente, mientras que Ni solo se detectó en la solución acuosa de NaCl, 0,100 mg L-1. Estas concentraciones de iones liberados no provocaron efectos citotóxicos en células similares a osteoblastos.
- ArtículoAcceso AbiertoIdentification of llama KRTAP7-1 and KRTAP8-1 fiber genes and polymorphism screening(2019)Keratin-associated proteins (KAP) are one of the main structural components of hair fiber. Within this protein group, high glycine tyrosine (HGT)-KAP play a crucial role in the definition of their physical-mechanical properties. Polymorphisms in HGT genes have been associated with the variation of different wool traits in sheeps and goats. The Argentine llama is a fiber-producing animal which is valued by the textile industry. However, the genes encoding for fiber proteins have not yet been identified in this species. Here, we focus on studying the HGT-KRTAP7-1 and KRTAP8-1 genes and their variation using the High Resolution Melting (HRM) technique in a sample of 117 llamas. Four single nucleotide polymorphisms (SNPs) were detected in KRTAP7-1, two of which were non-synonymous substitutions leading to amino acid changes in the protein. Of the 5 polymorphisms identified in KRTAP8-1, c.1-5A > G was located in the Kozak sequence, known to regulate protein synthesis level. The other four, two SNPs and one double nucleotide polymorphism (DNP), were found in the coding region and produced three amino acid replacement: c.43 T > C and c.45C > A (p.Y15Q), c.46 G > T (p.G16W) and c.173 A > G (p.Y58C). In summary, most of the polymorphisms found in both KRTAP7-1 and KRTAP8-1 genes produce non-conservative amino acid changes involving tyrosine and glycine residues, which are essential to maintain HGT protein properties. Therefore, these mutations as well as the regulatory SNP here identified could modify the fiber characteristics. We discuss the possible impact of these polymorphisms on KAP7-1 and KAP8-1 structure and/or interaction with other fiber proteins.
- ArtículoAcceso AbiertoCharacterization and expression analysis of KIT and MITF-M genes in llamas and their relation to white coat color(2019)The llama (Lama glama) is a fiber-producing species that presents a wide range of coat colors, among which white is one of the most important for the textile industry. However, there is little information about the molecular mechanisms that control the white phenotype in this species. In domestic mammals, a white coat is usually produced by mutations in the KIT proto-oncogene receptor tyrosine kinase (KIT) and microphthalmia-associated transcription factor (MITF) genes. In this work we have sequenced and described the coding regions of KIT and MITF-M, the melanocyte-specific isoform, and the two transcriptional variants MITF-M( ) and MITF-M(+). Moreover, we studied the expression of these genes in the skin of white and colored llamas. Although no variants were revealed to be associated with white coat color, significant differences between phenotypes were observed in the expression levels of KIT and MITF-M. Interestingly, white llamas expressed less MITF-M(+) than did colored ones, which is consistent with a consequent reduction in the synthesis of melanin. Even though our results indicate that downregulation of KIT and MITF-M expression is involved in white phenotype production in llamas, the causative gene of white coat color remains unknown.
- ArtículoAcceso AbiertoTYR Gene in Llamas: Polymorphisms and Expression Study in Different Color Phenotypes(2019)Tyrosinase, encoded by TYR gene, is an enzyme that plays a major role in mammalian pigmentation. It catalyzes the oxidation of L-dihydroxy-phenylalanine (DOPA) to DOPA quinone, a precursor of both types of melanin: eumelanin and pheomelanin. TYR is commonly known as the albino locus since mutations in this gene result in albinism in several species. However, many other TYR mutations have been found to cause diluted phenotypes, like the Himalayan or chinchilla phenotypes in mice. The llama (Lama glama) presents a wide variety of coat colors ranging from non-diluted phenotypes (eumelanic and pheomelanic), through different degrees of dilution, to white. To investigate the possible contribution of TYR gene to coat color variation in llamas, we sequenced TYR exons and their flanking regions and genotyped animals with diluted, non-diluted, and white coat, including three blue-eyed white individuals. Moreover, we analyzed mRNA expression levels in skin biopsies by qPCR. TYR coding region presented nine SNPs, of which three were non-synonymous, c.428A > G, c.859G > T, and c.1490G > T. We also identified seven polymorphisms in non-coding regions, including two microsatellites, an homopolymeric repeat, and five SNPs: one in the promoter region (c.1-26C > T), two in the 30 -UTR, and two flanking the exons. Although no complete association was found between coat color and SNPs, c.1-26C > T was partially associated to diluted phenotypes. Additionally, the frequency of the G allele from c.428A > G was significantly higher in white compared to non-diluted. Results from qPCR showed that expression levels of TYR in white llamas were significantly lower (p < 0.05) than those in diluted and non-diluted phenotypes. Screening for variation in regulatory regions of TYR did not reveal polymorphisms that explain such differences. However, data from this study showed that TYR expression levels play a role in llama pigmentation.
- ArtículoAcceso AbiertoNAT2 and oral clefts: evaluation of genetic risk and the relative importance of embryo and maternal genotypes(2019)Non-syndromic cleft lip with or without cleft palate (NSCLP) is a congenital malformation that shows the characteristics of a multifactorial pathology. In order to describe the genetic predisposition to this disorder, NAT genes were analyzed with special interest since they codify for N-acetyltransferases, the enzymes responsible for the biotransformation of arylamines, hydrazine drugs and a great number of toxins and carcinogens present in diet, cigarette smoke and the environment. The allelic transmission of NAT2 that determines the slow acetylator phenotype in 174 trios (case-mother/father) from ECLAMC (Latin American Collaborative Study of Congenital Malformations) maternities in Argentina was evaluated. The *4, *5B, *6, and *7 variants by PCR-RFLP were analyzed. A higher risk for the 5B*5B* genotypes (OR=2. 24; p=0.050) was found, at the expense of the cases from Patagonia, without the influence of the maternal genotype.