RESUMEN
In this study we have analysed and compared the genomic composition, meiotic behaviour, and meiotic affinities of Zea perennis and Zea mays ssp. mays. To do so we studied the parental taxa and the interspecific hybrid Zea perennis x Zea mays ssp. mays, using classical cytogenetic methods, as well as GISH and FISH. GISH enabled us to recognize the genomic source of each chromosome involved in the meiotic configurations of this hybrid, and established the genomic affinities between their parental species. The results obtained here reinforce the hypothesis of the amphiploid origin of Zea perennis and, together with previous research, indicate that the chromosomes with divergent repetitive sequences in maize and Zea luxurians could be the remnants of a relict parental genome not shared with Zea perennis.
Asunto(s)
Cruzamientos Genéticos , Genoma de Planta , Hibridación Fluorescente in Situ/métodos , Zea mays/genética , Cromosomas de las Plantas , ADN de Plantas/genética , Meiosis , Especificidad de la Especie , Zea mays/clasificaciónRESUMEN
OBJECTIVE: To analyze the most relevant anomalies, seen in a sequential segmental transverse views approach to imaging the fetal heart, that provide clues to the diagnosis of complete transposition of the great arteries (TGA). METHODS: We reviewed retrospectively all the cases of isolated TGA diagnosed in our center or submitted for a second opinion through the spatio-temporal image correlation (STIC) telemedicine (TELE-STIC) program. Only transverse cardiac sweeps were obtained. Digital video clips and STIC volumes were reviewed. The abnormal features on four-chamber, five-chamber, three-vessel (3V) and three vessels and trachea (3VT) views were analyzed. RESULTS: The study population consisted of eight fetuses with TGA with normal extracardiac anatomy. The gestational age ranged from 13 to 32 (mean, 23) weeks. The maternal age ranged from 25 to 42 (mean, 32) years. A normal four-chamber view was seen in seven cases. Only one case demonstrated a significant ventricular septal defect. At the level of the five-chamber view a straight course arterial vessel arose from the left ventricle with lateral branches in all fetuses. In the 3V view, the ascending aorta was seen reaching more anteriorly than was the pulmonary artery in six cases. At the level of the 3VT view, two vessels (transverse aortic arch and superior vena cava) rather than three were seen in all cases. CONCLUSION: Our proposed sequential segmental approach to imaging the fetal heart apparently allows, in five-chamber and 3VT views, clear and confident signs to be detected that aid diagnosis of TGA.
Asunto(s)
Ecocardiografía , Transposición de los Grandes Vasos/diagnóstico por imagen , Ultrasonografía Prenatal , Adulto , Femenino , Edad Gestacional , Humanos , Embarazo , Estudios RetrospectivosRESUMEN
The present review summarizes our classical and molecular cytogenetic investigations in the genus Zea. The results obtained from the meiotic behavior analysis of Zea species and hybrids, confirm the amphiploid nature of all species in the genus, with a basic number of x = 5 chromosomes. All species with 2n = 20 are diploidized allotetraploids, whereas Z. perennis (2n = 40) is an allooctoploid with four genomes somewhat divergent from one another. These analyses also revealed the existence of postzygotic reproductive isolation among Zea species. Our studies using genomic in situ hybridization (GISH) provide evidence about the evolutionary relationships among maize and its allied species, and reveal remarkable genomic divergences. Particularly, knob sequences were not completely shared between taxa previously considered to be closely related. Our data strongly suggest that the teosinte Z. mays parviglumis is not the only progenitor of cultivated maize. Introgression of Tripsacum into cultivated maize cannot be discarded.
Asunto(s)
Genoma de Planta , Zea mays/genética , ADN de Plantas/genética , Hibridación in Situ/métodos , Hibridación Fluorescente in Situ , Zea mays/clasificación , Zea mays/ultraestructuraRESUMEN
Nucleotide sequences of Rubisco Large Subunit (rbcL) and the internal transcribed spacers (ITS) of nrDNA were obtained for the five species of Larrea and one species each of Bulnesia (ITS only) and Plectrocarpa (rbcL only). Parsimony analyses were conducted, including sequences from seven genera of Zygophyllaceae reported by other authors-Kallstroemia, Zygophyllum, Augea, Fagonia, Pintoa, Guaiacum, and Porlieria. The main conclusions of the present study are (1) the Argentine endemic Plectrocarpa tetracantha belongs to the subfamily Larreoideae (New World Clade); (2) all three phylogenies obtained from rbcL, ITS, and combined data sets show a close relationship between the tetraploid L. cuneifolia (sect. Bifolium) and the diploid multifoliolate pair L. nitida-L. ameghinoi (sect. Larrea), which could result from a possible intersectional hybrid origin of the tetraploid; (3) L. divaricata (sect. Bifolium) and L. tridentata (sect. Bifolium) form a highly supported monophyletic group, which agrees with previous cytogenetic and molecular evidence; and (4) the rate of nucleotide substitution of rbcL was estimated based on geological and fossil records. Under the molecular clock hypothesis, nucleotide sequence divergence between L. divaricata and L. tridentata suggests a Late Neogene (8.4 to 4.2 mybp) time of arrival of the diploid ancestors of L. tridentata to North American deserts.
Asunto(s)
Evolución Molecular , Filogenia , Plantas/genética , Ribulosa-Bifosfato Carboxilasa , Núcleo Celular/genética , ADN de Cloroplastos/genética , ADN de Plantas/química , ADN de Plantas/genética , ADN Espaciador Ribosómico/genética , Variación Genética , Geografía , Datos de Secuencia Molecular , Mutación , América del Norte , Proteínas de Plantas/genética , Plantas/clasificación , Análisis de Secuencia de ADN , Factores de TiempoRESUMEN
Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-alpha, 12 with recombinant IFN-alpha-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 10(5) IU/kg of weight in children or 6 x 10(6) IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 x 10(4) IU/kg in children or 3 x 10(6) IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.