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Biomedical subjects

L L Villa

Publications and source records attributed to L L Villa.

60 records · Page 4Linked to original sources
PubMed1987

A direct method for cDNA cloning employing translation-released mRNA.

1. A new cloning procedure is described for cDNA synthesis from mRNA released by in vitro translation of polysomes in a cell-free amino acid incorporating system. The usefulness of the method lies in the feasibility of employing nanogram amounts of mRNA. 2. Complementary DNA is synthesized directly in the translation mixture simply by adjusting the concentration of some components and removing ribosomes by boiling and centrifugation. 3. As an example, we report here the construction and characterization of a cDNA clone corresponding to chick alpha(I)procollagen starting from a collagen-synthesizing polysome fraction obtained from chick embryos.

Amino Acyl-tRNA Synthetases↗
PubMed1986

Human papillomavirus DNA sequences in penile carcinomas in Brazil.

To detect the presence of human papillomavirus (HPV) DNA in penile cancers, 18 squamous-cell carcinomas were studied by Southern blot analysis. All specimens were from Brazilian patients ranging in age from 31 to 78 years. Of these, 7 harbored DNA sequence homology. Most positive specimens contained more than 100 copies of viral DNA. No HPV 16 was detected in our samples. Presence of HPV DNA sequences in the samples studied was not correlated with the patients' age or race, nor with extent or progress of disease.

Adult↗
PubMed1984

Construction of a cDNA clone corresponding to mouse alpha 1(IV) procollagen.

A new procedure for the synthesis of double stranded cDNA, based upon release of mRNA by "in vitro" translation, was used to clone type IV collagen. Collagen synthesizing polysomes selectively isolated from a mouse parietal yolk sac carcinoma (PYS-2) were used for translation in an heterologous cell-free system. Translation products were collagenase-sensitive and displayed an electrophoretic mobility correspondent to type IV collagen. Translation released mRNA was employed to construct a 100 base pairs long cDNA clone which hybridized to a 7,800 nucleotides long mRNA. Peptides synthesized by "in vitro" translation of hybrid selected mRNA displayed an electrophoretic mobility compatible with that of alpha 1 (IV) collagen, were sensitive to collagenase and were immunoprecipitated by anti-type IV collagen antibody.

Animals↗
PubMed1980

Induction of cytoplasmic petite in yeast by guanidine hydrochloride: combined treatment with other inducing agents.

We have studied the induction of rho- mutants by guanidine hydrochloride (GuHCl) in combination with other known inducers: ethidium bromide (EB), berenil and ultraviolet light. Competition was observed when cells were simultaneously treated with optimal concentrations of EB and GuHCl; on the other hand, treatment of cells with EB in the presence of non-inducing concentrations of GuHCl resulted in the stimulation of rho- induction of EB. Furthermore, using a strain which upon treatment with high EB concentrations shows recovery of respiratory competence, the presence of GuHCl did not interfere either with the early phase of induction or with the recovery phase, but it did interfere in a competitive fashion with the final irreversible phase of EB induction. In the case of berenil, a synergistic effect was seen when cells were pretreated with GuHCl. A synergistic induction was also observed when cells were submitted to UV prior to GuHCl treatment. These results suggest that GuHCl, EB and berenil act via some common step in their rho- induction pathways. Moreover, GuHCl may somehow be decreasing the efficiency of dark repair of ultraviolet lesions on mitochondrial DNA.

DNA, Mitochondrial↗