• Korean Journal of Plant Tissue Culture
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• v.22 no.4
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• pp.235-240
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• 1995

The development of selectable markers for transformation has been a major factor in the successful genetic manipulation of plant. We established a new selectable marker system for tobacco transformation using chimeric adenosine deaminase (ADA) gene, which confers resistance to cytotoxic adenosine analogues, 9-$\beta$-D-arabinofuranosyl adenine(Ara-A) and cordycepin. The transformants with the chimeric ADA gene in tobacco grew in the presence of normally lethal level of cytotoxic adenosine analogues, 100 $\mu$M Ara-A and 50 $\mu$M cordycepin. We successfully distinguished transformed shoot from non-transformed shoot on the same selectable media with cytotoxic adenosine analogues. In this selectable media, we were able to select seeds with/ without ADA gene from transgenic tobacco seeds. Theses results show that the mammalian ADA gene may serve as a new selectable marker for tobacco transformation.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.165-171
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• 2001

New visible and fast assay system have been developed for tobacco transformant introduced with adenosine deaminase (ADA) marker gene, which converts cytotoxic adenosine analogues to non-toxic inosine analogues and ammonia. Ammonia was changed to blue color in the solution of phenol-nitoprusside and alkaline-hypochlorite. It was possible to detect activity of ADA visibly on the holes of 96 well plate using tiny explant of transgenic tobacco leaves within 1 hour incubation time. As substrates of ADA enzyme from transgenic plant on the plate, a number of adenosine analogues such as 9-D-arabinofuranosyl adenine, cordycepin, 2'-deoxyadenosine, adenosine and xylofuranosyl adenine were possible for detection of ADA activity. Optimal condition of substrate for ADA enzyme was each 10 mM and pH 7.5 in adenosine solution. Especially, transgenic plant did not convert adenosine to inosine and ammonia in the presence of ADA inhibitor deoxycoformycin, which means that ammonia produced from transgenic plant is due to expression of ADA gene. Now, we show that this detection system can be easily, sensitively, fast and cheaply as well as visibly assayed in vitro as GUS gene system with very small size of transformant explant.

• Biomolecules & Therapeutics
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• v.1 no.1
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• pp.98-102
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• 1993

The therapeutic effectiveness of adenine arabinoside(tora-A) and its conjugate of prednisone(BR-8702-AP) was compared in Herpes simplex Virus Type 1 (HSV-1) infected BALB/C mice. The BALB/C mouse was infected with HSV-1(700 PFU/mouse) intranasally. Among mice infected intranasally with virus, a mortality rate of 100% was observed. On the oral administration of non-toxic doses of ara-A or BR-8702-AP(125 mg /kg/day) for 5 consecutive days 2 hours after virus infection, the tora-A was highly effective in reducing mortality to 0% (P<0.001) and BR-8702-AP was also effective in reducing mortality to 15% (P<0.01). In this model infection, the virus was first replicated in the lung and transmitted to the brain. Both arts-A and BR-8702-AP did not inhibit the viral replication in the lung, but they inhibited the viral transmission to the brain. However, the BR-8702-AP was less effective than the aria-A to prevent transmission of virus to brain. Therefore, the reduced mortality due to tora-A or BR-8702-AP therapy was associated with inhibition of viral transmission to brain.

• The Korean Journal of Nuclear Medicine
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• v.32 no.4
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• pp.374-381
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• 1998

Purpose: I-131 labeled (2'-deoxy-2'-iodo-${\beta}$-D-arabinofuranosyl) adenine (IAD) may be involved in DNA synthesis during active proliferation of tumor cells. We conducted this study to find out the biodistribution of IAD and it's feasibility for scintigraphic tumor imaging. Materials and Methods: Tosyl acetyl-adenosine was dissolved in acetonitrile, and I-131-NaI was added and heated to synthesize IAD. Female Fisher 344 rats innoculated with breast tumor cells were injected with 0.27 MBq of IAD. Rats were sacrificed at 0.5, 1, 2, 4, 24h and the % of injected dose per gram of tissue (%ID/g) was determined. For scintigraphy, rats bearing breast cancer were administered with 1.11 MBq of IAD and imaging was performed after 2 and 24h. Then, rat body was fixed and microtomized slice was placed on radiographic film for autoradiography. Results: %ID/g of tumor was 0.74 (0.5h),0.73 (1h), 0.55 (2h), 0.38 (4h), and 0.05 (24h), respectively. At 1h after injection, %ID/g of tumor was higher than that of heart (0.34), liver (0.42), spleen (0.47), kidney (0.69), muscle (0.14), bone (0.33) and intestine (0.51). However, %ID/g of tumor was lower than blood (1.06), lung (0.77), and thyroid (177.71). At 4h, %ID/g of tumor in comparison with other tissue did not change. Tumor contrast expressed by tumor to blood ratio was 0.69 and tumor to muscle ratio was 5.11 at 1h. However, these ratios did not improve through 24h. On autoradiogram and scintigraphy at 2 and 24 hour, the tumor was well visualized. Conclusion: This results suggest that IAD may have a potential for tumor scintigraphy. However, further work is needed to improve localization in tumor tissue.