• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.77-89
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• 1998

Background: Genetic and environmental factors are known to affect the incidence and severity of asthma. Stimulation of $\beta_2$-Adrenergic Receptor ($\beta_2$AR) results in smooth muscle relaxation, leading to decrease in resistance of airflow. The gene encoding the $\beta_2$AR has recently been seguenced. The $\beta_2$AR genotype at the polymorphic loci of codons 16, 27, 34, and 164 was known to cause changes in the amino acids. The relationships between the structure of the $\beta_2$AR and its functions are being elucidated. Purpose : The gene encoding the $\beta_2$AR was carried out to assess the frequency of polymorphisms in bronchial asthma, to determine wheather these polymorphisms have any relation to the severity, or nocturnal symptoms in bronchial asthma. Methods: The subjects studied were 103 patients with bronchial asthma, which consisted of 30 mild episodic, 32 mild persistent, 17 moderate, and 24 severe asthma patients. The polymorphisms of the $\beta_2$AR gene were detected by mutated allele specific amplification (MASA) method at the codons 16,27,34, and 164. Results: The most frequent polymorphism was arginine 16 to glycine. The other two polymorphisms, valine 34 to methionine and glutamine 27 to glutamic acid occured in 11 and 6 patients respectively. The polymorphism of threonine 164 to isoleucine was not found in our enrolled patients. The homozygous polymorphism of $\beta_2$AR gene was found in only arginine 16 to glycine (12.6%). The heterozygous polymorphisms of $\beta_2$AR gene were in arginine 16 to glycine, valine 34 to methionine, and glutamine 27 to glutamic acid, as 65.1 %,10.7%, and 5.8% respectively in asthma patients. The presence of agrginine 16 to glycine heterozygous or/and homozygous polymorphism was associated in severe asthma (p=0.015), but there was no association between the other three polymorphisms and the severity of asthma. The frequency of the $\beta_2$AR gene polymorphisms was no relation in nocturnal asthma as compared with non-nocturnal asthma. Conclusion: The arginine 16 to glycine polymorphism of the $\beta_2$AR gene is the most frequently found in asthma patients and association with severe asthma. But there was no association between the polymorphism of the $\beta_2$AR gene and nocturnal asthma.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.2
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• pp.136-151
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• 1984

The purpose of this study is to find out the linkage relationship of the resistance genes Wbph1 and Wbph2 which are known to be present in the rice cultivar N22 and ARC 10239 respectively, with the genetic markers which are identified as the specific linkage tester. Crosses were made between the resistant parents and the genetic marker stocks and their F$_2$ populations were grown out in the field. The genetic segregations of the marker character were studied and the seeds were harvested individual plant base. These F$_3$ seeds were grown into plant-line base in the greenhouse and their responses to the whitebacked planthopper were tested. Then the linkage relationship between the F$_2$ plant marker character and the F$_3$ resistance responses to the whitebacked planthopper were examined. In the F$_2$ generation of the crosses between the resistant parent N22 and the genetic marker stocks, the genetic markers, such as lg, d-t, g, la, bl and gl, showed the segregation of 3 dominance to 1 recessiveness, and the Bh marker segregated into 9:7 ratio. Another 4 marker genes, such as Cl, gh, Lh and bc, did not show the good fittness to the expected value. In the F$_2$ generation of the crosses between the resistant parent ARC 10239 and the genetic marker stocks, the genetic markers, such as Cl, lg, Pn, g, la, bl and gl, showed the segregation of 3 dominance to 1 recessiveness, and the Bh gene segregation fitted well to the 9:7. The rest 4 genetic markers, such as gh, Lh, nl and be, did not show the good fitness to the expected ratio. The resistance genes Wbphl of N22 and the Wbph2 of ARC 10239 appeared to be single dominant gene each. The Wbphl gene was linked with the marker gene, liguleless (lg) of linkage group II with the recombination value of 36.8%, and with the black hull (Bh) with the value of 35.9%. The Wbph2 gene appeared to be independent of all the markers tested here, such as Cl, lg, Pn, g, Lh, la, nl, bl, bc, gl, Bh, of linkage gtoup I, II, III, IV, VI, VII, VIII, IX, X, XI, and XII respectively. That the Wbph2 linkage relations were not investigated was regarded as the causes that the tested marker genes on the chromosome were located with the resistance gene at the distant loci, and of the phenctypic properties of the marker characters. The Wbph2 linkage relations should be reexamined in the cross combinations of linkage group Ⅶ, Ⅷ, Ⅹ and XII including linkage group V which was not tested in this experiment.