The ASIP gene in the llama (Lama glama): Alternative transcripts, expression and relation with color phenotypes.

The Agouti gene (ASIP) is one of the most important genes for coat color determination in mammals. It has a complex structure with several promoters and alternative non-coding first exons that are transcribed into mRNAs with different 5'UTR. These mRNA isoforms regulate the temporal and spatial expression of the gene, producing diverse pigmentation patterns. Here, we studied ASIP transcriptional variants and their expression in the skin of llamas with different coat color phenotypes. We also described the ASIP locus, including promoter usage and the splicing events that originate each transcript variant. Using 5'RACE-PCR we isolated seven ASIP transcripts with alternative 5'UTR, where exons 1A, 1A', 1C, 1D, and a novel non-coding exon 1A" were identified. Additionally, new alternative spliced forms were found. The diversity of ASIP 5'UTRs is originated by a complex pattern of alternative promoter usage, multiple transcription start sites and splicing events that include exon skipping and alternative 3' splicing site selection. We found that ASIP was highly expressed in llamas with white and brown phenotypes while black animals presented very low expression. The main responsible for this difference was a fusion transcript between ASIP and NCOA6 genes, which was present in the skin of white and brown llamas but not in the black ones. The rest of ASIP transcripts presented very low expression in the skin, indicating that the main regulation point for ASIP gene expression is at the transcriptional level. Nevertheless, the characteristics of the 5'UTRs sequences suggest that alternative transcripts could be regulated differently at the protein synthesis level.

Correction to: Implementation and impact of pediatric antimicrobial stewardship programs: a systematic scoping review.

The original article [1] contains an error in Fig. 1 whereby the number of selected articles of the first box is incorrect.

Implementation and impact of pediatric antimicrobial stewardship programs: a systematic scoping review.

Background: Antibiotics are the most common medicines prescribed to children in hospitals and the community, with a high proportion of potentially inappropriate use. Antibiotic misuse increases the risk of toxicity, raises healthcare costs, and selection of resistance. The primary aim of this systematic review is to summarize the current state of evidence of the implementation and outcomes of pediatric antimicrobial stewardship programs (ASPs) globally. Methods: MEDLINE, Embase and Cochrane Library databases were systematically searched to identify studies reporting on ASP in children aged 0-18 years and conducted in outpatient or in-hospital settings. Three investigators independently reviewed identified articles for inclusion and extracted relevant data. Results: Of the 41,916 studies screened, 113 were eligible for inclusion in this study. Most of the studies originated in the USA (52.2%), while a minority were conducted in Europe (24.7%) or Asia (17.7%). Seventy-four (65.5%) studies used a before-and-after design, and sixteen (14.1%) were randomized trials. The majority (81.4%) described in-hospital ASPs with half of interventions in mixed pediatric wards and ten (8.8%) in emergency departments. Only sixteen (14.1%) studies focused on the costs of ASPs. Almost all the studies (79.6%) showed a significant reduction in inappropriate prescriptions. Compliance after ASP implementation increased. Sixteen of the included studies quantified cost savings related to the intervention with most of the decreases due to lower rates of drug administration. Seven studies showed an increased susceptibility of the bacteria analysed with a decrease in extended spectrum beta-lactamase producers E. coli and K. pneumoniae; a reduction in the rate of P. aeruginosa carbapenem resistance subsequent to an observed reduction in the rate of antimicrobial days of therapy; and, in two studies set in outpatient setting, an increase in erythromycin-sensitive S. pyogenes following a reduction in the use of macrolides. Conclusions: Pediatric ASPs have a significant impact on the reduction of targeted and empiric antibiotic use, healthcare costs, and antimicrobial resistance in both inpatient and outpatient settings. Pediatric ASPs are now widely implemented in the USA, but considerable further adaptation is required to facilitate their uptake in Europe, Asia, Latin America and Africa.

Characterization and expression analysis of KIT and MITF-M genes in llamas and their relation to white coat color.

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.

Molecular characterization of the llama FGF5 gene and identification of putative loss of function mutations.

Llama, the most numerous domestic camelid in Argentina, has good fiber-production ability. Although a few genes related to other productive traits have been characterized, the molecular genetic basis of fiber growth control in camelids is still poorly understood. Fibroblast growth factor 5 (FGF5) is a secreted signaling protein that controls hair growth in humans and other mammals. Mutations in the FGF5 gene have been associated with long-hair phenotypes in several species. Here, we sequenced the llama FGF5 gene, which consists of three exons encoding 813 bp. cDNA analysis from hair follicles revealed the expression of two FGF5 alternative spliced transcripts, in one of which exon 2 is absent. DNA variation analysis showed four polymorphisms in the coding region: a synonymous SNP (c.210A>G), a single base deletion (c.348delA), a 12-bp insertion (c.351_352insCATATAACATAG) and a non-sense mutation (c.499C>T). The deletion was always found together with the insertion forming a haplotype and producing a putative truncated protein of 123 amino acids. The c.499C>T mutation also leads to a premature stop codon at position 168. In both cases, critical functional domains of FGF5, including one heparin binding site, are lost. All animals analyzed were homozygous for one of the deleterious mutations or compound heterozygous for both (i.e. c.348delA, c.351_352insCATATAACATAG/c.499T). Sequencing of guanaco samples showed that the FGF5 gene encodes a full-length 270-amino acid protein. These results suggest that FGF5 is likely functional in short-haired wild species and non-functional in the domestic fiber-producing species, the llama.

Genetic diversity and conservation status of managed vicuña (Vicugna vicugna) populations in Argentina.

The vicuña (Vicugna vicugna) was indiscriminately hunted for more than 400 years and, by the end of 1960s, it was seriously endangered. At that time, a captive breeding program was initiated in Argentina by the National Institute of Agricultural Technology (INTA) with the aim of preserving the species. Nowadays, vicuñas are managed in captivity and in the wild to obtain their valuable fiber. The current genetic status of Argentinean vicuña populations is virtually unknown. Using mitochondrial DNA and microsatellite markers, we assessed levels of genetic diversity of vicuña populations managed in the wild and compared it with a captive population from INTA. Furthermore, we examined levels of genetic structure and evidence for historical bottlenecks. Overall, all populations revealed high genetic variability with no signs of inbreeding. Levels of genetic diversity between captive and wild populations were not significantly different, although the captive population showed the lowest estimates of allelic richness, number of mitochondrial haplotypes, and haplotype diversity. Significant genetic differentiation at microsatellite markers was found between free-living populations from Jujuy and Catamarca provinces. Moreover, microsatellite data also revealed genetic structure within the Catamarca management area. Genetic signatures of past bottlenecks were detected in wild populations by the Garza Williamson test. Results from this study are discussed in relation to the conservation and management of the species.