Glossy15, an APETALA2-like gene from maize that regulates leaf epidermal cell identity.

Vegetative development in many plants progresses through distinct juvenile and adult phases. In maize, the transition from juvenile to adult shoot development affects a variety of leaf epidermal cell traits. These include epicuticular waxes, leaf hairs, and cell wall characteristics. Previous genetic and phenotypic analyses have shown that the maize Glossy15 (Gl15) gene is required for the expression of juvenile epidermal traits after leaf 2. We report here the molecular cloning of the Gl15 gene using a defective Suppressor-Mutator (dSpm) element insertion as a transposon-tag. Consistent with the gl15 mutant phenotype, the pattern of Gl15 mRNA expression was correlated with a juvenile leaf epidermal cell identity and was regulated by upstream factors such as Corngrass1. The Gl15 gene encodes a putative transcription factor with significant sequence similarity to the Arabidopsis regulatory genes APETALA2 and AINTEGUMENTA, which act primarily to regulate floral organ identity and ovule development. This finding expands the known functions of APETALA2-related genes to include the control of both vegetative and reproductive lateral organ identity and provides molecular support for the hypothesis that leaves and floral organs are related structures derived from a common growth plan.

Glossy15 Controls the Epidermal Juvenile-to-Adult Phase Transition in Maize.

Loss-of-function mutations at the maize Glossy15 (Gl15) locus alter the normal transition from juvenile-to-adult growth by conditioning the abbreviated expression of juvenile epidermal cell traits and the coordinate precocious expression of adult epidermal cell features. These include epicuticular wax composition, cell wall characteristics, and the presence or absence of differentiated epidermal cell types (e.g., epidermal macrohairs and bulliform cells). A transposon-induced mutable allele of Glossy15 (gl15-m1) was isolated and employed in both phenotypic and genetic analyses to characterize the role of Gl15 in the maize juvenile-to-adult phase transition. Comparisons between Gl15-active and Gl15-inactive somatic sectors in the leaves of variegated plants demonstrated that the Gl15 gene product acts in a cell-autonomous manner to direct juvenile epidermal differentiation but does not affect factors that regulate the overall process of phase change. Examination of the gl15-m1 phenotype in the Corngrass1, Teopod1, and Teopod2 mutant backgrounds showed that the prolonged expression of juvenile epidermal traits associated with these mutations also required Gl15 activity. These results support a model whereby the cell-autonomous Gl15 gene product responds to a juvenility program that operates throughout the vegetative shoot to condition the juvenile differentiation of maize leaf epidermal cells.

Characterization of inverted repeats from plasmid-like DNAs and the maize mitochondrial genome.

Integrated inverted repeat (IR) sequences similar to those of the S plasmids have been isolated from the genomes of the normal and S type male-sterile cytoplasms of maize mitochondria. The nucleotide sequences of both the IRs and their flanking regions have distinguished and characterized several different types of repeats. The repeats may be involved in the recombinational process that occurs continuously in the mitochondrial genome. One cloned fragment, derived from a fertile revertant and containing sequences similar to S-2, does not appear to act as a typical transposable element during reversion. Several of the flanking regions examined contain a small repeat of 34 base pairs, in which a nonanucleotide segment is found with similarity to the yeast mitochondrial promoter.

Fertility restoration and mitochondrial nucleic acids distinguish at least five subgroups among cms-S cytoplasms of maize (Zea mays L.).

Differences in fertility restoration and mitochondrial nucleic acids permitted division of 25 accessions of S-type male sterile cytoplasm (cms-S) of maize into five subgroups: B/D, CA, LBN, ME, and S(USDA). S cytoplasm itself (USDA cytoplasm) was surprisingly not representative of cms-S, since only two other accessions, TC and I, matched its mitochondrial DNA pattern. CA was the predominant subgroup, containing 18 of the 25 accessions. The B/D and ME subgroups were the most fertile and LBN the most sterile. The exceptional sterility of LBN cytoplasm makes it the most promising of the 25 cms-S accessions for the production of hybrid seed. The most efficient means of quantifying the fertility of the subgroups was analysis of pollen morphology in plants having cms-S cytoplasm and simultaneously being heterozygous for nuclear restorer-of-fertility (Rf) genes. This method took advantage of the gametophytic nature of cms-S restoration. The inbred NY821LERf was found to contain at least two restorer genes for cms-S. Fertility differences were correlated with mitochondrial nucleic acid variation in the LBN, ME, and S (USDA) subgroups.

Estudio comparativo de los pediculos intrahepaticos en las piezas de hepatectomias por cancer del higado. / Comparative study of the intrahepatic pedunculus in surgical pieces in hepatectomies by liver neoplasms

Se investigo un grupo de controles sin tumor hepatico y otro con las vias de diseminacion de las neoplasias primarias (hepatomas) y secundarias del higado (metastasis de origen vesicular y colonico) en piezas de 8 pacientes operados. Los autores senalan la gran importancia que tiene el estudio histopatologico intraoperatorio por congelacion y diferido de las piezas

Consideraciones sobre la tecnica y resultados en la gastrectomia total con interposicion yeyunal. / Technic and results in the total gastrectomy with interposed jejunal loop

Se realizaron en un periodo de 6 anos, 31 gastrectomias totales con asa yeyunal interpuesta, con una mortalidad del 6,2%.Los autores consideran la tecnica quirurgica utilizada. Se efectuo el seguimiento de 11 de estos pacientes para determinar los resultados funcionales. Los parametros de evaluacion fueron el control clinico, la restituicion del transito, la endoscopia y la determinacion de grasa fecal. El tiempo y calidad de vida alcanzados por los pacientes, sugieren que desde el punto de vista funcional, la interposicion del asa yeyunal aislada es el procedimiento de eleccion despues de una gastrectomia total por cancer

Estudio comparativo de los pediculos intrahepaticos en las piezas de hepatectomias por cancer del higado. / Comparative study of the intrahepatic pedunculus in surgical pieces in hepatectomies by liver neoplasms

Se investigo un grupo de controles sin tumor hepatico y otro con las vias de diseminacion de las neoplasias primarias (hepatomas) y secundarias del higado (metastasis de origen vesicular y colonico) en piezas de 8 pacientes operados. Los autores senalan la gran importancia que tiene el estudio histopatologico intraoperatorio por congelacion y diferido de las piezas

Consideraciones sobre la tecnica y resultados en la gastrectomia total con interposicion yeyunal. / Technic and results in the total gastrectomy with interposed jejunal loop

Se realizaron en un periodo de 6 anos, 31 gastrectomias totales con asa yeyunal interpuesta, con una mortalidad del 6,2%.Los autores consideran la tecnica quirurgica utilizada. Se efectuo el seguimiento de 11 de estos pacientes para determinar los resultados funcionales. Los parametros de evaluacion fueron el control clinico, la restituicion del transito, la endoscopia y la determinacion de grasa fecal. El tiempo y calidad de vida alcanzados por los pacientes, sugieren que desde el punto de vista funcional, la interposicion del asa yeyunal aislada es el procedimiento de eleccion despues de una gastrectomia total por cancer