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N Katagiri

Publications and source records attributed to N Katagiri.

43 records · Page 3Linked to original sources
PubMed1975

Chemical synthesis and sequence studies of deoxyribooligonucleotides which constitute the duplex sequence of the lactose operator of Escherichia coli.

We have synthesized the deoxyribooligonucleotide fragments, constituting the sequence of the lac operator of Escherichia coli. Two of these fragments, d(pApApTpTpGpTpTpApT) (nonamer) and d(pApApTpTpGpTpGpApG) (nonamer), corresponding to the 5' termini of lac operator have been synthesized by the phosphodiester method. The remaining four fragments, d(ApCpApApTpT) (hexamer), d(ApTpApApCpApApTpT) (nonamer), d(ApApTpTpGpTpGpApGpCpGpG) (dodecamer), and d(ApApTpTpGpTpTpApTpCpCpGpCpTpC) (pentadecamer), have been synthesized by an improved phosphotriester method. All of the compounds were first characterized by venom and spleen phosphodiesterase digestion to obtain their base composition. The sequence of these oligonucleotides was fully confirmed by the characteristic mobility shifts of their partial venom phosphodiesterase digestion products on two-dimensional homochromatography. A comparative study of the two methods for the synthesis of oligonucleotides has revealed that the phosphotriester method is more convenient than the phosphodiester method because of higher yields and ease of handling large scale preparations.

Base Sequence↗
PubMedDate not supplied

A simple method for cryopreservation of purified adult pig pancreatic cells.

Cryopreservation of islet cells may benefit many aspects of islet transplantation including storage, transport of islets, immunomodulation, reduction of the exocrine contaminants. Isolation and purification of islets from large mammalian pancreases have been encountered by many problems. We reported an autodigestion method for preparation of adult pig pancreatic cells. In this paper, we describe a newly invented simple method for cryopreservation of purified adult pig pancreatic cells. The viability and function of islet cells before (precryo.) and after (postcryo.) the cryopreservation procedure were compared. Islet cell harvested by the autodigestion method were suspended in cryoprotectant "Cell banker." A biofreezing vessel "Bicell" containing a cryogenic vial with cell suspension was frozen at -80 degrees C. After 4 wk, the cryogenic vial was rapidly thawed at 37 degrees C water, the islet cells were washed and cultured for overnight. Number of dithizone-stained precryo. and postcryo. cells were 1.71 +/- 0.5 x 10(5) and 1.75 +/- 0.98 x 10(5) cells/pancreas respectively; therefore, the viability was 99%. Insulin release following high and low concentrations of glucose in precryo. (12.02 +/- 3.63 ng/ml: low-glucose, 9.81 +/- 3.59 ng/ml: high glucose) and precryo. (5.57 +/- 4.03 ng/ml: low-glucose, 10.24 +/- 8.88 ng/ml: high glucose) cells showed a marked improvement in response in postcryo. cells. The insulin content of precryo. and postcryo. cells were 914.4 +/- 277.4 and 93.6 +/- 15.4 ng/ml, respectively. This simple and efficient cryopreservation protocol may be applied for a large-scale storage of adult pig islet cells to establish an islet bank for transplantation.

Age Factors↗
PubMedDate not supplied

Deamination of cyclaradine by adenosine deaminase under high pressure.

The deamination of cyclaradine corresponding to a carbocyclic analogue of ara-A having anti-HSV activity by adenosine deaminase was examined under various pressure. The deamination of (+)- and (+/-)-cyclaradine was remarkably facilitated by high pressure, and the rate was increased with increasing of pressure. However, (-)-cyclaradine was not deaminated even under high pressure.

Adenosine Deaminase↗