Uso de la técnica SSCP para detectar mutaciones puntuales del ADN mitocondrial humano

We evaluate the use of SSCP (single strand conformational polymorphism), a relatively easy and inexpensive technique for the detection of point mutations with a sensibility around 80% under ideal conditions. To test the technique, we used samples of volunteers whose DNA had been previously characterized for the presence or absence of 5 mitochondrial RFLPs. Optimization of the tests included variations in TBE (1X and 0,5X) and of glycerol concentration (10%, 5% and no glycerol) in polyacrylamide gels. Four out of five RFLPs were detected under the conditions used and could be applied routinely without using restriction enzymes. In addition, the SSCP technique allowed detection of unknown mutations in a 394 bp nucleotide segment of the hypervariable (HVI) region of mtDNA. Differences corresponding to different haplotypes were detected, helping to distinguish groups within the same subtype. Sequencing of two samples of subtype B1 with differential migration on SSCP gels, proved the existence in seven different nucleotides.En el presente trabajo se evalúa la técnica de SSCP (polimorfismo de conformación de cadena individual de ADN) para detectar mutaciones puntuales, tanto por su sensibilidad en la detección (alrededor 80% en condiciones ideales), como por su implementación fácil y económica. Se utilizaron como controles positivos y negativos, ADN de voluntarios caracterizados previamente para las mutaciones puntuales de 5 RFLPs mitocondriales. Para la optimización de la prueba fueron ensayadas concentraciones variables del tampón TBE (1X y 0,5X) y del glicerol (10%, 5% y 0) en geles de poliacrilamida. Cuatro de los 5 RFLPs fueron detectados en las condiciones utilizadas y pueden ser usados en estudios de rutina sin usar enzimas de restricción. Además, la técnica SSCP permitió determinar mutaciones desconocidas en un segmento de 394 nucleótidos de la región hipervariable (HVI) del ADNmt. Diferencias en correspondencia a los distintos haplotipos fueron detectados e incluso permitió discernir grupos dentro del mismo subtipo. La secuenciación de dos muestras del subtipo B1 con migración diferencial en SSCP, corroboró la existencia de siete nucleótidos distinto

Three novel polymorphic microsatellite markers for the glaucoma locus GLC1B by datamining tetranucleotide repeats on chromosome 2p12-q12

In order to identify new markers around the glaucoma locus GLC1B as a tool to refine its critical region at 2p11.2-2q11.2, we searched the critical region sequence obtained from the UCSC database for tetranucleotide (GATA)n and (GTCT)n repeats of at least 10 units in length. Three out of four potential microsatellite loci were found to be polymorphic, heterozygosity ranging from 64.56% to 79.59%. The identified markers are useful not only for GLC1B locus but also for the study of other disease loci at 2p11.2-2q11.2, a region with scarcity of microsatellite markers

Loss-of-function mutations in the ATP13A2/PARK9 gene cause complicated hereditary spastic paraplegia (SPG78)

Hereditary spastic paraplegias are heterogeneous neurodegenerative disorders characterized by progressive spasticity of the lower limbs due to degeneration of the corticospinal motor neurons. In a Bulgarian family with three siblings affected by complicated hereditary spastic paraplegia, we performed whole exome sequencing and homozygosity mapping and identified a homozygous p.Thr512Ile (c.1535C>T) mutation in ATP13A2. Molecular defects in this gene have been causally associated with Kufor-Rakeb syndrome (#606693), an autosomal recessive form of juvenile-onset parkinsonism, and neuronal ceroid lipofuscinosis (#606693), a neurodegenerative disorder characterized by the intracellular accumulation of autofluorescent lipopigments. Further analysis of 795 index cases with hereditary spastic paraplegia and related disorders revealed two additional families carrying truncating biallelic mutations in ATP13A2. ATP13A2 is a lysosomal P5-type transport ATPase, the activity of which critically depends on catalytic autophosphorylation. Our biochemical and immunocytochemical experiments in COS-1 and HeLa cells and patient-derived fibroblasts demonstrated that the hereditary spastic paraplegia-associated mutations, similarly to the ones causing Kufor-Rakeb syndrome and neuronal ceroid lipofuscinosis, cause loss of ATP13A2 function due to transcript or protein instability and abnormal intracellular localization of the mutant proteins, ultimately impairing the lysosomal and mitochondrial function. Moreover, we provide the first biochemical evidence that disease-causing mutations can affect the catalytic autophosphorylation activity of ATP13A2. Our study adds complicated hereditary spastic paraplegia (SPG78) to the clinical continuum of ATP13A2-associated neurological disorders, which are commonly hallmarked by lysosomal and mitochondrial dysfunction. The disease presentation in our patients with hereditary spastic paraplegia was dominated by an adult-onset lower-limb predominant spastic paraparesis. Cognitive impairment was present in most of the cases and ranged from very mild deficits to advanced dementia with frontotemporal characteristics. Nerve conduction studies revealed involvement of the peripheral motor and sensory nerves. Only one of five patients with hereditary spastic paraplegia showed clinical indication of extrapyramidal involvement in the form of subtle bradykinesia and slight resting tremor. Neuroimaging cranial investigations revealed pronounced vermian and hemispheric cerebellar atrophy. Notably, reduced striatal dopamine was apparent in the brain of one of the patients, who had no clinical signs or symptoms of extrapyramidal involvement

Clinical characteristics of rod and cone photoreceptor dystrophies in patients with mutations

METHODS. Eight patients-four diagnosed with retinitis pigmentosa (RP) and four with conerod dystrophy (CRD), carrying causal C8orf37 mutations-were clinically evaluated, including extensive medical history taking, slit-lamp biomicroscopy, ophthalmoscopy, kinetic perimetry, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), autofluorescence (AF) imaging, and fundus photography. RESULTS. In families A and D, respectively, one and three patients showed a classic RP phenotype with night blindness followed by concentric loss of visual field. Severe visual loss to light perception occurred early in the course of the disease. The symptoms initiated during infancy (family A) or adolescence (family D). Ophthalmoscopy revealed macular atrophy, bone spicules, attenuated vessels, and waxy pale optic discs. SD-OCT showed profound photoreceptor degeneration and AF demonstrated atrophy of the retinal pigment epithelium (RPE). ERG responses were nonrecordable in these patients. In families B and C, the patients were diagnosed with CRD. Initial symptoms were photophobia or loss of visual acuity and occurred during infancy (family B) or adolescence (family C). Ophthalmoscopy and AF revealed profound macular RPE atrophy and SD-OCT demonstrated macular photoreceptor degeneration. ERG responses were severely reduced in a cone-rod pattern or were nonrecordable. Interestingly, both patients in family B demonstrated polydactyly. CONCLUSIONS. Mutations in C8orf37 give rise to an early or adolescent-onset autosomal recessive CRD or RP phenotype with early macular atrophy. The occurrence of postaxial polydactyly in one family suggests a syndromic phenotype, which may indicate C8orf37 has a ciliary function

MCM3AP in recessive Charcot-Marie-Tooth neuropathy and mild intellectual disability

Defects in mRNA export from the nucleus have been linked to various neurodegenerative disorders. We report mutations in the gene MCM3AP, encoding the germinal center associated nuclear protein (GANP), in nine affected individuals from five unrelated families. The variants were associated with severe childhood onset primarily axonal (four families) or demyelinating (one family) Charcot-Marie-Tooth neuropathy. Mild to moderate intellectual disability was present in seven of nine affected individuals. The affected individuals were either compound heterozygous or homozygous for different MCM3AP variants, which were predicted to cause depletion of GANP or affect conserved amino acids with likely importance for its function. Accordingly, fibroblasts of affected individuals from one family demonstrated severe depletion of GANP. GANP has been described to function as an mRNA export factor, and to suppress TDP-43-mediated motor neuron degeneration in flies. Thus our results suggest defective mRNA export from nucleus as a potential pathogenic mechanism of axonal degeneration in these patients. The identification of MCM3AP variants in affected individuals from multiple centres establishes it as a disease gene for childhood-onset recessively inherited Charcot-Marie-Tooth neuropathy with intellectual disability.Peer reviewe

Avifauna asociada a dos cacaotales tradicionales en la región e la chontalpa, Tabasco, México

The results of a year investigation of the avian assemblages present in two cocoa plantations in the Chontalpa region, Tabasco are reported. Birds were counted using the fixed radius point count procedure. 3,994 birds representing 84 species were counted. One of the sites was richer and more diverse in species than the other and vegetation measures suggest that these differences may be related to the variety in plant diversity, density and cover between the two sites. The value of cocoa plantations for the conservation of an important segment of the original avian biodiversity present in highly modified landscapes are discussed.Se registra un estudio anual acerca de los conjuntos de aves presentes en dos plantaciones de cacao en la región de la Chontalpa, Tabasco. Las aves fueron muestreadas mediante conteos por puntos de radio fijo. Se contaron 3,994 aves representando a 84 especies. Uno de los sitios resultó con mayor riqueza y diversidad que el otro, aspecto que parece estar relacionado a diferencias en diversidad, densidad y cobertura de la vegetación entre los dos sitios. Se discute el valor de los cacaotales en las tierras bajas de Tabasco como reservorios importantes de la biodiversidad avifaunística

Bibliotecas después del sismo. Región Ica

Situational study about devastated libraries in Ica region (Peru) after the earthquake of August 15, 2007. Emerged as research objectives: • To know the real situation of the libraries after the earthquake. • Synthesize relevant information • Develop and draft the report to the academic and professional community • Produce and edit a video showing images about libraries destroyed. For the effect was applied qualitative and quantitative methods of social research

Uso de la técnica SSCP para detectar mutaciones puntuales del ADN mitocondrial humano

En el presente trabajo se evalúa la técnica de SSCP (polimorfismo de conformación de cadena individual de ADN) para detectar mutaciones puntuales, tanto por su sensibilidad en la detección (alrededor 80% en condiciones ideales), como por su implementación fácil y económica. Se utilizaron como controles positivos y negativos, ADN de voluntarios caracterizados previamente para las mutaciones puntuales de 5 RFLPs mitocondriales. Para la optimización de la prueba fueron ensayadas concentraciones variables del tampón TBE (1X y 0,5X) y del glicerol (10%, 5% y 0) en geles de poliacrilamida. Cuatro de los 5 RFLPs fueron detectados en las condiciones utilizadas y pueden ser usados en estudios de rutina sin usar enzimas de restricción. Además, la técnica SSCP permitió determinar mutaciones desconocidas en un segmento de 394 nucleótidos de la región hipervariable (HVI) del ADNmt. Diferencias en correspondencia a los distintos haplotipos fueron detectados e incluso permitió discernir grupos dentro del mismo subtipo. La secuenciación de dos muestras del subtipo B1 con migración diferencial en SSCP, corroboró la existencia de siete nucleótidos distintos

Presupuestos de tiempo en una tropa de monos aulladores (Alouatta palliata) en el parque Yumká, Tabasco, México

The results of a seven-month study of the time budgets of a troop of howler monkeys (Alouatta palliata) inhabiting the forested area of Yumká park in central Tabasco, Mexico are presented. The troop consisted of 28 individuals and their behavior was observed for seven days each month. The results indicated the predominance of resting behavior (49 min/hr of observation), followed by feeding (7.9 min/hr), locomotion (4.1 min/hr), traveling (2.1 min/hr), social interactions (0.8 min/hr) and howling (0.1 min/hr). The observed time budgets were intimately linked to the consumption of large quantities of leaves and to the spatial and temporal availability of the food resources exploited by the howlers. The relevance of the data to improve our understanding of howler monkey responses to fragmentation and isolation of their natural habitats by human activity are discussedSe presentan los resultados de un estudio parcial acerca de los presupuestos de tiempo en una tropa de monos aulladores (Alouatta palliata) en el parque Yumká en Tabasco, México. El estudio tuvo una duración de siete meses, de noviembre de 2000 a abril de 2001. Se basó en observaciones de la conducta de una tropa de monos aulladores compuesta por 28 individuos que existen en la zona de vegetación selvática del parque Yumká. Los resultados indicaron una predominancia de la actividad de descanso (44.9 min/hr de observación), seguida por alimentación (7.9 min/hr), locomoción (4.1 min/hr), viaje (2.1 min/hr), interacciones sociales (0.8 in/hr) y bramidos (0.1 min/hr). Las actividades manifestadas por los aulladores estuvieron íntimamente relacionadas al consumo de grandes cantidades de hojas y a la dispersión espacial y temporal de los recursos alimenticios utilizados. Se discute la relevancia de los datos para comprender las adaptaciones de esos primates a la fragmentación y aislamiento de sus hábitats por la actividad humana