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3.
Fungal Biol ; 125(7): 560-575, 2021 07.
Article in English | MEDLINE | ID: mdl-34140152

ABSTRACT

The increased availability and production of lignocellulosic agroindustrial wastes has originated proposals for their use as raw material to obtain biofuels (ethanol and biodiesel) or derived products. However, for biomass generated from lignocellulosic residues to be successfully degraded, in most cases it requires a physical (thermal), chemical, or enzymatic pretreatment before the application of microbial or enzymatic fermentation technologies (biocatalysis). In the context of enzymatic technologies, fungi have demonstrated to produce enzymes capable of degrading polysaccharides like cellulose, hemicelluloses and pectin. Because of this ability for degrading lignocellulosic material, researchers are making efforts to isolate and identify fungal enzymes that could have a better activity for the degradation of plant cell walls and agroindustrial biomass. We performed an in silico analysis of alpha-glucoronidase in 82 accessions of the genus Aspergillus. The constructed dendrograms of amino acid sequences defined the formation of 6 groups (I, II, III, IV, V, and VI), which demonstrates the high diversity of the enzyme. Despite this ample divergence between enzyme groups, our 3D structure modeling showed both conservation and differences in amino acid residues participating in enzyme-substrate binding, which indicates the possibility that some enzymes are functionally specialized for the specific degradation of a substrate depending on the genetics of each species in the genus and the condition of the habitat where they evolved. The identification of alpha-glucuronidase isoenzymes would allow future use of genetic engineering and biocatalysis technologies aimed at specific production of the enzyme for its use in biotransformation.


Subject(s)
Aspergillus , Glycoside Hydrolases , Aspergillus/classification , Aspergillus/enzymology , Aspergillus/genetics , Fermentation , Fungal Proteins/genetics , Fungal Proteins/metabolism , Glycoside Hydrolases/genetics , Lignin/metabolism , Phylogeny , Protein Binding
4.
Heredity (Edinb) ; 124(3): 397-409, 2020 03.
Article in English | MEDLINE | ID: mdl-31863032

ABSTRACT

The wheat leaf rust fungus, Puccinia triticina, is found in the major wheat growing regions of the world and is a leading cause of yield loss in wheat. Populations of P. triticina are highly variable for virulence to resistance genes in wheat and adapt quickly to resistance genes in wheat cultivars. The objectives of this study were to determine the genetic relatedness of worldwide collections of P. triticina using restriction site associated genotyping by sequencing. A total of 558 isolates of P. triticina from wheat producing regions in North America, South America, Europe, the Middle East, Ethiopia, Russia, Pakistan, Central Asia, China, New Zealand, and South Africa were characterized at 6745 single nucleotide loci. Isolates were also tested for virulence to 20 near-isogenic lines that differ for leaf rust resistance genes. Populations that were geographically proximal were also more closely related for genotypes. In addition, groups of isolates within regions that varied for genotype were similar to groups from other regions, which indicated past and recent migration across regions. Isolates from tetraploid durum wheat in five different regions were highly related with distinct genotypes compared to isolates from hexaploid common wheat. Based on a molecular clock, isolates from durum wheat found only in Ethiopia were the first to diverge from a common ancestor form of P. triticina that is found on the wild wheat relative Aegilops speltoides, followed by the divergence of isolates found worldwide that are virulent to durum wheat, and then by isolates found on common wheat.


Subject(s)
Plant Diseases , Puccinia , Asia , China , Ethiopia , Europe , Genotype , Middle East , New Zealand , North America , Pakistan , Plant Diseases/microbiology , Puccinia/genetics , Russia , South Africa , South America
5.
Phytopathology ; 109(8): 1453-1463, 2019 Aug.
Article in English | MEDLINE | ID: mdl-30932734

ABSTRACT

Many plant pathogenic fungi have a global distribution across diverse ecological zones and agricultural production systems. Puccinia triticina, the wheat leaf rust fungus, is a major pathogen in many wheat production areas of the world. The objective of this research was to determine the genetic relatedness of P. triticina in different worldwide regions. A total of 831 single-uredinial isolates collected from 11 regions were characterized for multilocus genotype at 23 simple sequence repeat loci and for virulence to 20 lines of wheat with single genes for leaf rust resistance. A total of 424 multilocus genotypes and 497 virulence phenotypes were found. All populations had high heterozygosity and significant correlation between virulence and molecular variation, which indicated clonal reproduction. The populations from North America and South America, Central Asia and Russia, and the Middle East and Europe were closely related for multilocus genotypes and many individual isolates from other continental regions were closely related. Twenty-seven multilocus genotypes were found in more than one continental region, and 13 of these had isolates with identical virulence phenotypes. The wide geographic distribution of identical and highly related multilocus genotypes of P. triticina indicated past and more recent migration events facilitated by the spread of clonally produced urediniospores.


Subject(s)
Plant Diseases , Triticum , Asia, Central , Europe , Genotype , Middle East , North America , Plant Diseases/microbiology , Russia , South America , Triticum/microbiology
6.
Biotechnol Prog ; 34(6): 1314-1334, 2018 11.
Article in English | MEDLINE | ID: mdl-30009567

ABSTRACT

Several of the over 200 known species of Agave L. are currently used for production of distilled beverages and biopolymers. The plants live in a wide range of stressful environments as a result of their resistance to abiotic stress (drought, salinity, and extreme temperature) and pathogens, which gives the genus potential for germplasm conservation and biotechnological applications that may minimize economic losses as a result of the global climate change. However, the limited knowledge in the genus of genome structure and organization hampers development of potential improved biotechnological applications by means of genetic manipulation and biocatalysis. We reviewed Agave and plant sequences in the GenBank NCBI database for identifying genes with biotechnological potential for fermentation, bioenergy, fiber improvement, and in vivo plant biopolymer production. Three-dimensional modeling of enzyme structures in plant accessions revealed structural differences in sucrose 1-fructosyltransferase, fructan 1-fructosyltransferase, fructan exohydrolase (1-FEH), cellulose synthase (CES), and glucanases (EGases) with possible effects in fructan, sugar, and biopolymer production. Although the coding genes of FEH and enzymes involved in biopolymer production (CES, sucrose synthase, and EGases) remain unidentified in Agave L., our results could aid isolation of such genes in Agave. By comparing nucleotide and amino acid sequences in accessions of Agave and other plants, knowledge may be gained about transcriptional regulation and enzymatic activity factors. Future study is needed of biotechnological application of Agave genes for crop breeding aided by genetic engineering and biocatalysis. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1314-1334, 2018.


Subject(s)
Agave/metabolism , Biocatalysis , Biopolymers/metabolism , Biotechnology/methods , Fermentation/physiology
7.
J Mol Evol ; 86(6): 404-423, 2018 07.
Article in English | MEDLINE | ID: mdl-29992348

ABSTRACT

Agave L. is a genus of economic importance, and many of the 166 species in the American plant genus Agave L. inhabit high-stress environments, which makes the genus promising for facing global climate change. However, sustainable use of economically important species without interfering with their ecology and evolution requires generating knowledge about the factors responsible for their genetic variation and diversity and, on this basis, their adaptation and speciation. Few genetic studies exploring the evolutionary relationships, speciation processes, genetic variability and diversity within species of Agave are currently available. Analyses of rDNA loci have been performed with the purpose of determining the genetic variability and diversity of the genus Agave, and these loci have been used as genetic markers of ploidy. However, the factors involved in the diversity of 5S rDNA regions in Agave have not yet been studied in depth. Our study explored the possible mechanisms of genetic (retroelements) and epigenetic (DNA methylation) diversity in 5S rDNA regions in Agave. We characterized the 5S rDNA gene tandem in species of the genus with different ploidy numbers and determined the levels of methylation in 13 haplotypes of 5S rDNA and in four non-transcribed spacers (NTS). Our results showed highly dynamic methylation with a high percentage in haplotypes and NTS of 5S rDNA regions in Agave. The characterization of the 5S rDNA tandem array in Agave revealed vestigial remains of the Cassandra terminal-repeat retrotransposon in miniature (TRIM). Our analysis supported previous results suggesting that in species of Agave L., regulation and diversity of 5S rDNA regions are controlled by coordinated genetic and epigenetic events, which will vary according to the species and the level of ploidy. The artificial pressure to which some agave crops are subjected may affect the mechanisms of evolution of gene 5S rDNA.


Subject(s)
Agave/genetics , DNA Methylation/genetics , DNA, Ribosomal/genetics , Genetic Variation , Retroelements/genetics , Base Sequence , DNA, Intergenic/genetics , DNA, Ribosomal/chemistry , Ecotype , Haplotypes/genetics , Nucleic Acid Conformation , Phylogeny
8.
J Plant Physiol ; 195: 80-94, 2016 May 20.
Article in English | MEDLINE | ID: mdl-27016883

ABSTRACT

Polyploidy has been widely described in many Agave L. species, but its influence on environmental response to stress is still unknown. With the objective of knowing the morphological adaptations and regulation responses of genes related to biotic (LEA) and abiotic (NBS-LRR) stress in species of Agave with different levels of ploidy, and how these factors contribute to major response of Agave against environmental stresses, we analyzed 16 morphological trials on five accessions of three species (Agave tequilana Weber, Agave angustifolia Haw. and Agave fourcroydes Lem.) with different ploidy levels (2n=2x=60 2n=3x=90, 2n=5x=150, 2n=6x=180) and evaluated the expression of NBS-LRR and LEA genes regulated by biotic and abiotic stress. It was possible to associate some morphological traits (spines, nuclei, and stomata) to ploidy level. The genetic characterization of stress-related genes NBS-LRR induced by pathogenic infection and LEA by heat or saline stresses indicated that amino acid sequence analysis in these genes showed more substitutions in higher ploidy level accessions of A. fourcroydes Lem. 'Sac Ki' (2n=5x=150) and A. angustifolia Haw. 'Chelem Ki' (2n=6x=180), and a higher LEA and NBS-LRR representativeness when compared to their diploid and triploid counterparts. In all studied Agave accessions expression of LEA and NBS-LRR genes was induced by saline or heat stresses or by infection with Erwinia carotovora, respectively. The transcriptional activation was also higher in A. angustifolia Haw. 'Chelem Ki' (2n=6x=180) and A. fourcroydes 'Sac Ki' (2n=5x=150) than in their diploid and triploid counterparts, which suggests higher adaptation to stress. Finally, the diploid accession A. tequilana Weber 'Azul' showed a differentiated genetic profile relative to other Agave accessions. The differences include similar or higher genetic representativeness and transcript accumulation of LEA and NBS-LRR genes than in polyploid (2n=5x=150 and 2n=6x=180) Agave accessions, thus suggesting a differentiated selection pressure for overcoming the lower ploidy level of the diploid A. tequilana Weber 'Azul'.


Subject(s)
Acclimatization , Agave/physiology , Gene Dosage/genetics , Genome, Plant/genetics , Agave/genetics , Agave/ultrastructure , Diploidy , Environment , Phenotype , Phylogeny , Plant Proteins/genetics , Plant Stomata/genetics , Plant Stomata/physiology , Plant Stomata/ultrastructure , Ploidies , Polyploidy , Stress, Physiological
9.
Eur Biophys J ; 40(9): 1101-7, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21701865

ABSTRACT

The ubiquitin protein belongs to the ß-grasp fold family, characterized by four or five ß-sheets with a single α-helical middle region. Ubiquitin-like proteins (Ubls) are structural homologues with low sequence identity to ubiquitin and are widespread among both eukaryotes and prokaryotes. We previously demonstrated by bioinformatics that P400, a polypeptide from the haloalkaliphilic archaeon Natrialba magadii, has structural homology with both ubiquitin and Ubls. This work examines the secondary structure of P400 by Fourier transform infrared spectroscopy (FTIR). After expression in Escherichia coli, recombinant P400 (rP400) was separated by PAGE and eluted pure from zinc-imidazole reversely stained gels. The requirement of high salt concentration of this polypeptide to be folded was corroborated by intrinsic fluorescence spectrum. Our results show that fluorescence spectra of rP400 in 1.5 M KCl buffer shifts and decreases after thermal denaturation as well as after chemical treatment. rP400 was lyophilized and rehydrated in buffer containing 1.5 M KCl before both immunochemical and FTIR tests were performed. It was found that rP400 reacts with anti-ubiquitin antibody after rehydration in the presence of high salt concentrations. On the other hand, like ubiquitin and Ubls, the amide I' band for rP400 shows 10% more of its sequence to be involved in ß-sheet structures than in α-helix. These findings suggest that P400 is a structural homologue of the ubiquitin family proteins.


Subject(s)
Archaeal Proteins/chemistry , Halobacteriaceae , Peptides/chemistry , Spectroscopy, Fourier Transform Infrared/methods , Ubiquitin/chemistry , Models, Molecular , Protein Refolding , Protein Structure, Secondary
10.
Phytopathology ; 100(4): 376-83, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20205541

ABSTRACT

Leaf rust, caused by Puccinia triticina, is the most prevalent and widespread disease of wheat in South America. The objective of this study was to determine whether genetically differentiated groups of P. triticina are currently present in South America and to compare the South American population with the previously characterized population in North America. In total, 130 isolates of P. triticina from the wheat-growing regions of Argentina, Brazil, Chile, Peru, and Uruguay, mostly from the 1990s to 2008, were tested for virulence on 20 lines of wheat with single genes for leaf rust resistance and for molecular genotypes with 23 simple-sequence repeat (SSR) markers. After removal of isolates with identical virulence and SSR genotypes, 99 isolates were included for further analysis. Principal coordinate analysis plots indicated five different groups of isolates based on SSR genotypes that also differed for virulence to leaf rust resistance genes. All pairs of groups, except for one pair, were significantly differentiated for SSR genotypes according to R(ST) statistics. All but two pairs of groups were significantly differentiated for virulence phenotype according to Phi(PT) statistics. Isolates in all five groups had high values of fixation index for SSR alleles and linkage disequilibrium was high across all isolates that indicated the clonal reproduction of urediniospores. Only one of the five P. triticina groups from South America was differentiated for SSR genotypes from all of the six P. triticina groups from North America. The high degree of similarity for SSR genotype of isolates from both South America and North America suggested a common European origin of P. triticina that was introduced to both continents. The emergence of the same P. triticina virulence phenotypes with highly related SSR genotypes in the United States in 1996 and in Uruguay in 1999 indicated the likely intercontinental migration of these genotypes from Mexico to both South America and North America.


Subject(s)
Basidiomycota/genetics , Genetic Variation , Triticum/microbiology , Demography , Evolution, Molecular , North America , Phylogeny , South America
11.
Rev. Fac. Nac. Salud Pública ; 27(3): 322-328, sep.-dic. 2009.
Article in Spanish | LILACS | ID: lil-636919

ABSTRACT

La psoriasis es una enfermedad inflamatoria crónica caracterizada por la hiperproliferación de queratinocitos como respuesta a la activación del sistema inmune. El manejo de esta patología es variado, pero las opciones terapéuticas disminuyen cuando la severidad aumenta, y hay que recurrir a medicaciones o terapias que traen mayores efectos secundarios no deseados. La fototerapia hace parte de los tratamientos utilizados en formas severas; la primera que se introdujo fue el uso de psoralenos más luz ultravioleta A (PUVA), pero es una terapia no del todo inocua que puede producir cataratas o inclusive cáncer de piel, lo que imposibilita su uso en algunos pacientes. Con el advenimiento de la terapia con luz ultravioleta B de banda estrecha (UVB-NB) en 1997, se abrió un nuevo espectro de alternativas de tratamiento para este tipo de pacientes, con similares características en cuanto a efectividad. Al comparar estos dos tipos de terapias, la literatura no es concluyente y deja un sinnúmero de dudas acerca de cuál de las dos terapias es más efectiva. Con la aparición de nuevas terapias, es importante conocer la más efectiva, pues son tratamientos menos costosos en comparación con los que están llegando al mercado.


Psoriasis is a chronic inflammatory disease characterized by keratinocyte hyperproliferation in response to activation of the immune system. The management of this condition is varied, but the therapeutic options decrease as the severity increases, and we must resort to medications or therapies that bring more unwanted side effects. Phototherapy is part of the treatments used in severe forms, the first to be introduced was the use of psoralen plus ultraviolet A light (PUVA), but it is not entirely safe therapy that can cause cataracts or even skin cancer, which precludes their use in some patients. With the advent of light therapy narrow band ultraviolet B (UVB-NB) in 1997, it opened a new spectrum of treatment alternatives for these patients, with similar characteristics in terms of effectiveness. By comparing these two types of therapies, the literature is not conclusive and leaves a host of questions about which of the two therapies is more effective. With the advent of new therapies, it is important to know the most effective, they are less expensive treatments compared with those who are coming to market.


Subject(s)
Ultraviolet Rays , Ficusin
12.
J Biomech ; 41(4): 744-52, 2008.
Article in English | MEDLINE | ID: mdl-18206156

ABSTRACT

The purpose of this work is to present the main interactions promoted by exercise and synthesize them into mathematical equations. It is intended to extend the ability of the compartmental glucose-insulin model introduced by Sorensen [1985. A physiologic model of glucose metabolism in man and its use to design and assess improved insulin therapies for diabetes. Ph.D. Dissertation, Chemical Engineering Department, MIT, Cambridge] to reproduce variations in the blood glucose concentration induced by exercise in diabetic patients and to complement the previous work by Lenart and Parker [2002. Modeling exercise effects in type I diabetic patients. In: Proceedings of the 15th Triennial World Congress, Barcelona, Spain] and Lenart, DiMascio and Parker [2002. Modeling glycogen-exercise interactions in type I diabetic patients. In: Proceedings of the A.I.Ch.E. Annual Meeting, Indianapolis, IN]. The immediate consequences of exercise are incorporated in this research: redistribution of blood flows, increments in peripheral glucose and insulin uptakes, and increment in hepatic glucose production. The extended model was verified with experimental data for light and moderate intensity exercise. In addition, data extrapolation was introduced to simulate heavy intensity exercise. The hepatic glycogen reservoir limits the peripheral glucose uptake for prolonged exercise. Therefore, the depletion and replenishment of hepatic glycogen were modeled, looking to reproduce the blood glucose levels for a type 1 diabetic patient during a normal day, with meal intakes, insulin infusions and/or boluses, and a predefined exercise regime. From the extensive simulation evaluation, it is found that the new exercise model provides a good approximation to the available experimental data from literature.


Subject(s)
Diabetes Mellitus, Type 1/metabolism , Diabetes Mellitus, Type 1/physiopathology , Exercise/physiology , Glycogen/metabolism , Models, Cardiovascular , Computer Simulation , Diabetes Mellitus, Type 1/therapy , Gluconeogenesis/physiology , Glucose/biosynthesis , Glucose/physiology , Glycogen/deficiency , Humans , Insulin/administration & dosage , Insulin/physiology
13.
Investig. andin ; 7(11): 29-37, sept. 2005.
Article in Spanish | LILACS | ID: lil-475944

ABSTRACT

Las tasas de mortalidad en bebés con muy bajo peso al nacer MBPN, son estudiadas ampliamente, encontrándose numerosos factores de riesgo. La mortalidad neonatal y perinatal es utilizada algunas veces como una medida de pronóstico en los estudios que evalúan la efectividad de las intervenciones.Un gran número de publicaciones presenta datos de supervivencia de neonatos pretérmino relacionados con cada semana de gestación. Las diferencias entre los estudios pueden reflejar diferencias de la población estudiada. Sin embargo los médicos y padres que desean saber el pronóstico de los neonatos pretérmino extremo, requieren información confiable basada en la edad gestacional, para planear los cuidados necesarios perinatales y posteriores. Los datos de probabilidad de supervivencia de los neonatos de alto riesgo, pueden ser de gran valor para la elaboración de guías de atención. Las gráficas de pronóstico neonatal específicas de la edad gestacional y el peso al nacimiento en los neonatos pretérmino, facilitan la toma de decisiones a médicos y a padres.


Subject(s)
Infant, Newborn , Critical Care/methods , Critical Care , Critical Care/classification , Critical Care/trends , Infant Mortality/trends
14.
Investig. andin ; 7(10): 38-47, abr. 2005.
Article in Spanish | LILACS | ID: lil-475939

ABSTRACT

El país no cuenta con un instrumento validado para la identificación del riesgo obstétrico. El control prenatal es un programa de tamizaje multifásico, en el que se identifica el riesgo obstétrico de la paciente, con el fin de generar la atención específica que ésta necesite con base en el riesgo identificado. El control prenatal es la prueba tamiz para detectar el alto riesgo obstétrico durante el embarazo. No se ha validado con criterio científico la consulta prenatal como herramienta de tamizaje del riesgo obstétrico. El contenido de las consultas prenatales parece ser más ritualista que el producto de un programa de control de salud racional. Para complicar aún más la evaluación del control prenatal, hay un efecto variable según las poblaciones. No existe ninguna duda sobre la amplia aceptación que tiene el control prenatal en el país. Aunque existe un consenso general sobre muchos factores prenatales y perinatales que aumentan el riesgo obstétrico, no se encuentra en la literatura un acuerdo que permita calcular tal grado de riesgo. Algunos de los registros disponibles comercialmente se han incorporado a los sistemas de puntuación de alto riesgo con el fin de clasificar a las pacientes en categorías de alto y bajo riesgo.


Subject(s)
Humans , Prenatal Care , Maternal Welfare/classification , Outcome and Process Assessment, Health Care/classification , Quality Assurance, Health Care/methods
15.
Phytopathology ; 94(2): 154-62, 2004 Feb.
Article in English | MEDLINE | ID: mdl-18943538

ABSTRACT

ABSTRACT The metapopulation structure of Phytophthora infestans sensu lato is genetically diverse in the highlands of Ecuador. Previous reports documented the diversity associated with four putative clonal lineages of the pathogen collected from various hosts in the genus Solanum. This paper simultaneously analyzes diversity of the complete collection of isolates, including a large number that had not yet been reported. This analysis confirmed the existence of three pathogen populations, which all appear to be clonal lineages, and that correspond to those previously reported as US-1, EC-1, and EC-3. No evidence was found from the analyses of recently collected isolates that would contradict earlier reports about these three lineages. In contrast, new data from a group of isolates from several similar hosts caused us to modify the previous description of clonal lineage EC-2 and its previously proposed hosts, S. brevifolium and S. tetrapetalum. Given the uncertainty associated with the identification of these hosts, which all belong to the section Anarrhichomenum, we refer to them as the Anarrhichomenum complex, pending further taxonomic clarification. New pathogen genotypes associated with the Anarrhichomenum complex were isolated recently that are A1 mating type and Ia mitochondrial DNA (mtDNA) haplotype, and therefore differ from the previously described EC-2 lineage, which is A2 and Ic, respectively. Because of uncertainty on host identification, we do not know if the new genotypes are limited to one host species and therefore represent yet another host-adapted clonal lineage. For now, we refer to the new genotypes and previously described EC-2 genotypes, together, as the pathogen group attacking the Anarrhichomenum complex. Two A2 isolates identical to the previously described EC-2 archetype were collected from severely infected plants of pear melon (S. muricatum). Pear melon is generally attacked by US-1, and this is the first clear case we have documented in which two distinct pathogen genotypes have caused severe epidemics on the same host. Based on presence of unique marker alleles (restriction fragment length polymorphism [RFLP] and mtDNA) and genetic similarity analysis using RFLP and amplified fragment length polymorphism data, EC-3 and isolates from the Anarrhichomenum complex are genetically distinct from all genotypes of P. infestans that have been reported previously. No current theory of historical migrations for this pathogen can adequately support a Mexican origin for EC-3 and genotypes of the Anarrhichomenum complex and they may, therefore, be palaeoendemic to the Andean highlands. To date, we have identified 15 hosts in the genus Solanum, in addition to the Anarrhichomenum complex, and some unidentified species of P. infestans sensu lato in Ecuador. Five of the Solanum hosts are cultivated. One isolate was collected from Brugmansia sanguinea, which represents the first report from Ecuador of a host of this pathogen that is not in the genus Solanum. However, P. infestans sensu lato was only found on flower petals of B. sanguinea. This study provides new insights into the population structure of highly specialized genotypes of P. infestans sensu lato in the Andean highlands. The results are discussed in light of previous hypotheses regarding the geographic origin of the pathogen.

16.
Phytopathology ; 90(2): 197-202, 2000 Feb.
Article in English | MEDLINE | ID: mdl-18944609

ABSTRACT

ABSTRACT Twenty-six isolates of a Phytophthora population from two wild solanaceous species, Solanum tetrapetalum (n 11) and S. brevifolium (n = 15), were characterized morphologically, with genetic and phenotypic markers, and for pathogenicity on potato and tomato. Based on morphology, ribosomal internal transcribed spacer region 2 (ITS2) sequence, and pathogenicity, all isolates closely resembled P. infestans and were tentatively placed in that species. Nonetheless, this population of Phytophthora is novel. Its primary host is neither potato nor tomato, and all isolates had three restriction fragment length polymorphism (RFLP) bands (probe RG57) and a mitochondrial DNA haplotype that have not been reported for P. infestans. All the isolates were the A2 mating type when tested with a P. infestans A1 isolate. The A2 mating type has not been found among isolates of P. infestans from potato or tomato in Ecuador. Geographical substructing of the Ecuadorian A2 population was detected. The three isolates from the village of Nono, identical to the others in all other aspects, differed by three RFLP bands; those from Nono lacked bands 10 and 16, but possessed band 19. Most of the Ecuadorian A2 isolates were nonpathogenic on potato and tomato, but a few caused very small lesions with sparse sporulation on necrotic tissue. Cluster analysis of multilocus genotypes (RFLP, mating type, and two allozymes) dissociated this A2 population from genotypes representing clonally propagated populations of P. infestans worldwide. The current hypotheses for the historical global movements of P. infestans do not satisfactorily explain the origin or possible time of introduction into Ecuador of this A2 population. Assuming the population is P. infestans, its presence in Ecuador suggests either a hitherto unreported migration of the pathogen or an indigenous population that had not previously been detected.

17.
Phytopathology ; 88(3): 265-71, 1998 Mar.
Article in English | MEDLINE | ID: mdl-18944974

ABSTRACT

ABSTRACT Sixty Ecuadorian isolates of Phytophthora infestans from potato and 60 isolates from tomato were compared for dilocus allozyme genotype, mitochondrial DNA haplotype, mating type, and specific virulence on 11 potato R-gene differential plants and four tomato cultivars, two of which contained different Ph genes. Restriction fragment length polymorphism (RFLP) fingerprints of subsamples of isolates from each host were compared by using RG57 as the probe. All potato isolates had the allozyme genotype, haplotype, and mating type of the clonal lineage EC-1, which had been previously described in Ecuador. With the same markers, only one isolate from tomato was classified as EC-1; all others belonged to the globally distributed US-1 clonal lineage. RFLP fingerprints of isolate subsets corroborated this clonal lineage classification. Specific virulence on potato differentials was broadest among potato isolates, while specific virulence on tomato cultivars was broadest among tomato isolates. Some tomato isolates infected all tomato differentials but no potato differentials, indicating that specific virulence for the two hosts is probably controlled by different avirulence genes in P. infestans. In two separate experiments, the diameters of lesions caused by nine isolates from potato and 10 from tomato were compared on three tomato and three potato cultivars. All isolates produced larger lesions on the host from which they were isolated. No isolates were found that were highly aggressive on both tomato and potato. We conclude that there are two different populations of P. infestans in Ecuador and that they are separated by host.

18.
Phytopathology ; 87(4): 375-80, 1997 Apr.
Article in English | MEDLINE | ID: mdl-18945115

ABSTRACT

ABSTRACT The population genetic structure of Phytophthora infestans in Ecuador was assessed from 101 isolates collected from 1990 to 1992 and 111 isolates collected in 1993. All isolates were analyzed for mating type and allozyme genotype. Both samples were dominated (>95%) by a clonal lineage (EC-1) defined from neutral markers: 90/100 genotype for glucose-6-phosphate isomerase, 96/100 genotype for peptidase, A1 mating type, and a previously unreported nuclear DNA fingerprint. The remaining isolates belonged to the US-1 clonal lineage, which has a worldwide distribution. Isolates in the 1993 sample were analyzed for virulence and metalaxyl sensitivity. All representatives of EC-1 had complex patho-types, with three pathotypes representing >60% of the collection. There was variation for metalaxyl sensitivity. There was no evidence for geographical substructuring on the basis of neutral markers, but there was evidence for limited substructuring based on metalaxyl sensitivity and specific virulence. We hypothesize that EC-1 has been recently introduced to Ecuador.

19.
Profamilia ; 9(21): 20-39, 1993 Jun.
Article in Spanish | MEDLINE | ID: mdl-12344944

ABSTRACT

PIP: Statistical data describing the dramatic fertility decline and increase in contraceptive usage in Colombia since 1965 are presented in this article. Colombia's estimated crude birth rate, which fluctuated around 45/1000 for the first half of the 20th century, fell from 45 in 1965 to 41.3 around 1968, 36 in 1970, 31 in 1975, 28 in 1985, and 26 in 1990. The total fertility rate declined from an estimated 7.0 in 1960-65 to 6.7 in 1969, 4.5 in the 1973 census, 3.2 in the 1985 census, and 2.9 according to the 1990 Demographic and Health Survey. The most significant fertility declines occurred before 1975, but fertility continues to decline in rural and urban zones and in all regions of Colombia. Some isolated groups of women maintain high fertility. Rural women, women in the Atlantic region, women in consensual unions, less educated women, and those not employed outside the home had higher fertility rates. Marriage age, and important proximate fertility determinant, changed significantly only between 1975-86. Age at first union was around 19 years between 1969-76 vs. 21 years for 1986-90. The median age at first marriage was estimated at 22.1 years in 1976 and 22.8 in 1985. By 1985 the median age at first marriage was 23.4 years in urban areas and 2.2 years lower in rural areas. The causes of the fertility decline have not been precisely identified, although such factors as urbanization, improved health services, increasing educational levels, and female employment are believed to be involved. Colombia's crude death rate has declined from 22/1000 in 1930-51 to 13.5 in 1964, 9 in 1973, and 6 in 1985. The decline has been attributed to improved health conditions, introduction of vaccines and antibiotics, and general development of the medical sciences. The national infant mortality rate was 27/1000 live births in 1990, but elevated levels persist in the marginal areas of large cities, in remote rural areas, and among the least educated. Colombia's fertility decline has partially compensated for the mortality decline, and the rate of natural increase has slowed significantly. Around 1964-65, the Colombian Association of Medical Faculties and the institution that developed into PROFAMILIA began offering family planning services, and in 1969 the national government began offering family planning services through its maternal-child health program. The volume of the Ministry of Health Services has fluctuated considerably over the years in response to political pressures, and the other programs have endured political attacks from diverse quarters. But much of the population has firmly accepted contraception. In 1990, 69% of urban women, 61% of rural women, and 66% of all women currently in union used a method; 14% used pills, 12% IUDs and 2% rhythm, and 5% withdrawal.^ieng


Subject(s)
Birth Rate , Contraception Behavior , Demography , Fertility , Health Planning , Marriage , Mortality , Population Dynamics , Americas , Colombia , Contraception , Developing Countries , Family Planning Services , Latin America , Population , Social Sciences , South America
20.
Rev Med Chil ; 119(9): 1016-21, 1991 Sep.
Article in Spanish | MEDLINE | ID: mdl-1845093

ABSTRACT

Periarticular involvement and joint mobility were investigated in 100 non insulin dependent diabetic patients, compared to 100 healthy control subjects of similar age and sex. Periarticular involvement was much more common in diabetics (p < 0.01) including limitation of joint mobility (hands) (40% vs 9%), Dupuytren (29% vs 2%), palmar synovitis (59% vs 7%) and capsulitis (16% vs 1%). Diabetic patients with limitation of joint mobility had more neuropathy (80% vs 56%), retinitis proliferans (35% vs 17%) and alterations of the skin of the hands, compared to diabetics without limitation of joint mobility. Diabetes should be investigated in subjects with periarticular manifestations such as those described in this paper. Also, a more advanced stage of diabetes may be suspected in diabetics with such manifestations.


Subject(s)
Diabetes Mellitus, Type 2/complications , Finger Joint , Ligaments, Articular , Adult , Diabetes Mellitus, Type 2/physiopathology , Finger Joint/physiopathology , Humans , Joint Diseases/diagnosis , Joint Diseases/etiology , Ligaments, Articular/physiopathology , Movement , Wrist Joint/physiopathology
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