RESUMEN
Metarhizium anisopliae is a complex of cryptic species with wide geographical distribution and versatile lifestyles. In this study, 45 isolates of the Metarhizium genus harbored in the "Colección de Hongos Entomopatógenos" of the "Centro Nacional de Referencia de Control Biológico" from different substrates, insect-host, and localities from Colima, Mexico, were phylogenetically identified using the 5'end of translation elongation factor 1-α (5'TEF) and intergenic nuclear region MzFG543igs. Seven species were recognized, M. acridum (n = 26), M. pemphigi (n = 1), and within the PARB and MGT clades: M. anisopliae (N = 7; sensu stricto: n = 2; sensu lato: n = 5), M. brunneum (n = 2), M. guizhouense (n = 2), M. pingshaense (n = 2), and M. robertsii (n = 5). Twenty-nine SSR markers were developed for M. acridum; according to the analysis of 12 polymorphic SSR loci, M. acridum showed low genetic diversity, revealing five genotypes with a dominant one (n = 21). Based on the analysis of 13 specific SSR loci, 14 genotypes were identified within the PARB and MGT clades. This study contributes to generating valuable information about the community structure and genotypic diversity of Metharhizum species in the state of Colima, Mexico.
Asunto(s)
ADN de Hongos/genética , Variación Genética , Genotipo , Metarhizium/clasificación , Metarhizium/genética , Repeticiones de Microsatélite , Filogenia , Animales , Insectos/microbiología , Metarhizium/aislamiento & purificación , México , Factor 1 de Elongación Peptídica/genética , Plantas/microbiología , Reacción en Cadena de la Polimerasa , Alineación de Secuencia , Análisis de Secuencia de ADN , Microbiología del SueloRESUMEN
The entomopathogenic fungus Beauveria bassiana is used widely as a biological control agent against a wide range of insect pests globally. In this study, 44 Beauveria isolates from the state of Colima, Mexico harbored in the "Colección de Hongos Entomopatógenos" of the "Centro Nacional de Referencia de Control Biológico" and from different substrates, insect-hosts, and localities were characterized with molecular markers. All isolates were identified using a Bayesian phylogenetic analysis of translation elongation factor 1-α (TEF) and nuclear intergenic Bloc region. Forty-three isolates were identified as B. bassiana and grouped into two sub-clades, i.e., AFNEO_1 (nâ¯=â¯22; previously defined as a clade with African and Neotropical origin) and Bb clade (nâ¯=â¯21; closely associated with ex-type strain ARSEF 1564), and one isolate was identified as B. pseudobassiana. The fixation index (FSTâ¯=â¯0.493) established the genetic differentiation between AFNEO_1 and Bb clades. High genotype richness and genetic diversity of AFNEO_1 and Bb clades were revealed in sequence analysis of Bloc region and SSR genotyping. Moreover, the AFNEO_1 and Bb clades were confirmed as two independent clonally structured assemblages. Finally, the AMOVA detected no significant association between any combination of substrate, insect-host or geographical origin. High genetic variation of B. bassiana in Colima, Mexico could suggest a functional diversity among isolates that may include those effective against a specific insect pest.
Asunto(s)
Beauveria , Variación Genética , Insectos/microbiología , Animales , Beauveria/clasificación , Beauveria/genética , Beauveria/aislamiento & purificación , ADN Intergénico/genética , Ambiente , Marcadores Genéticos , Genotipo , Geografía , Especificidad del Huésped , Proteínas de Insectos/genética , México , Factor 1 de Elongación Peptídica/genética , Control Biológico de Vectores , FilogeniaRESUMEN
Species delimitation is a major topic in systematics. Species delimitation methods based on molecular data have become more common since this approach provides insights about species identification via levels of gene flow, the degree of hybridization and phylogenetic relationships. Also, combining multilocus mitochondrial and nuclear DNA leads to more reliable conclusions about species limits. Coalescent-based species delimitation methods explicitly reveal separately evolving lineages using probabilistic approaches and testing the delimitation hypotheses for several species. Within a multispecies, multilocus, coalescent framework, we were able to clarify taxonomic uncertainties within S. cyanostictus, an endangered lizard that inhabits a narrow strip of the Chihuahuan Desert in Mexico. We included, for the first time in a phylogenetic analysis, lizards from the three populations of S. cyanostictus recognized so far (East Coahuila, West Coahuila and Nuevo León). Phylogenetic analysis corroborates the hypothesis of two separately evolving lineages, i.e. the East and West Coahuila populations, as proposed in a previous study. We also found a distant phylogenetic relationship between the lizards from Nuevo León and those of East and West Coahuila. Finally, based on the species delimitation results, we propose and describe a new species of Sceloporus: S. gadsdeni sp. nov.
Asunto(s)
Sitios Genéticos , Lagartos/genética , Filogenia , Animales , Teorema de Bayes , Variación Genética , Masculino , México , Nucleótidos/genética , Especificidad de la EspecieRESUMEN
The administration of probiotics is a promising approach to reduce the prevalence of colon cancer, a multifactorial disease, with hereditary factors, as well as environmental lifestyle-related risk factors. Biogenic polyamines, putrescine, spermidine, and spermine are small cationic molecules with great roles in cell proliferation and differentiation as well as regulation of gene expression. Ornithine decarboxylase is the first rate-limiting enzyme for polyamine synthesis, and upregulation of ornithine decarboxylase activity and polyamine metabolism has been associated with abnormal cell proliferation. This paper is focused on studying the protective role of Lactobacillus casei ATCC 393 in a chemically induced mouse model of colon carcinogenesis, directing our attention on aberrant crypt foci as preneoplastic markers, and on polyamine metabolism as a possible key player in carcinogenesis. BALB/c mice were administered 1,2-dimethylhydrazine dihydrochloride (DMH) to induce colon cancer (20 mg/kg body weight, subcutaneous, twice a week for 24 weeks). L. casei ATCC 393 was given orally (106 CFU, twice a week), 2 weeks before DMH administration. Hematoxylin and eosin staining, high-performance liquid chromatography, and Western blotting were used to evaluate aberrant crypt foci, urinary polyamines, and ornithine decarboxylase expression in the colon. The experimental data showed that the preventive administration of L. casei ATCC 393 may delay the onset of cancer as it significantly reduced the number of DMH-induced aberrant crypt foci, the levels of putrescine, and the expression of ornithine decarboxylase. Hence, this probiotic strain has a prospective role in protection against colon carcinogenesis, and its antimutagenic activity may be associated with the maintenance of polyamine metabolism.