Cloning, sequencing and expression of the Taq I restriction-modification system.

The Taq I modification and restriction genes (recognition sequence TCGA) have been cloned in E. coli and their DNA sequences have been determined. Both proteins were characterized and the N-terminal sequence of the endonuclease was determined.

Cloning the DdeI restriction-modification system using a two-step method.

DdeI, a Type II restriction-modification system from the gram-negative anaerobic bacterium Desulfovibrio desulfuricans, recognizes the sequence CTNAG. The system has been cloned into E. coli in two steps.

Nucleotide sequence of the PaeR7 restriction/modification system and partial characterization of its protein products.

Bal31 deletion experiments on clones of the PaeR7 restriction-modification system from Pseudomonas aeruginosa demonstrate that it is arranged as an operon, with the methylase gene preceding the endonuclease gene. The DNA sequence of this operon agrees with in vitro transcription-translation assays which predict proteins of 532 amino acids, Mr = 59,260 daltons, and 246 amino acids, Mr = 27,280 daltons, coincident with the methylase and endonuclease genes, respectively. These predicted values coincide with the measured molecular weights of the purified, denatured PaeR7 endonuclease and methylase proteins.

The persistence and disappearance by washoff and dryfall of methoxychlor from soybean foliage--a preliminary study.

The persistence and disappearance (washoff or dryfall) of methoxychlor [2,2-bis(p-methoxyphenyl)-1,1,1-trichloroethane] from mature soybean [Glycine max (L.) Merrill] foliage was investigated in a small field plot study under natural rainfall conditions in 1977 and 1978. Residue analyses were conducted using whole plant samples.

Fluid resuscitation in live Escherichia coli shock in puppies.

The infusion of live E. coli in the puppy produces a severe and usually lethal model of pediatric septic shock with characteristic reduction in cardiac output and blood pressure. Hemodynamic abnormalities are partially reversed with fluid resuscitation alone, and large volumes, supplemented with albumin well within tolerated fluid loads, produce the most pronounced corrections of these derrangements.

The importance of different calorie sources in the intravenous nutrition of infants and children.

The intravenous infusion of amino acid and carbohydrate solutions is a well-established technique for nutritional support of the pediatric surgical patient. By using peripheral veins for total parenteral nutrition (TPN), weight gain can be achieved and the complications of central venous catheters avoided. Over a 2-year period, 45 patients from 1 day to 16 years of age received peripheral TPN in which fat provided a major portion of the daily calories.

Crohn's disease in children and adolescents: is inadequate weight gain a valid indication for surgery?

Seventy children and adolescents hospitalized for Crohn's disease at the University of Michigan Medical Center between 1966 and 1976 are reviewed. Thirty-three of these children were managed medically and 37 underwent a total of 60 operative procedures. There were 33 bowel resections, 7 appendectomies, 4 abscess drainages, 3 bowel bypasses, and 13 miscellaneous operative procedures.

Importance of bicarbonate in retinal function.

This study demonstrates a requirement for bicarbonate in retinal function. Omission of bicarbonate, with either phosphate or Tris used to maintain a constant pH, leads to significant changes in both the electroretinogram potentials and metabolism of the isolated rat retina. Electroretinograms in bicarbonate-free media show a selective loss of the b wave and a decline in the amplitudes of the a wave and Slow PIII.