Annual Report 2003

Change of the molecular weightforms of inhibins A and B with agein the bovine testisInhibin is a dimeric protein composed ofan subunit and either one of two subunits( A or B = inhibin A or B, respectively).Inhibin is synthesized as the largest precursorform (105 kDa), which is processed successivelyto form the lowest molecular massform (29~32 kDa) through the smaller 55, 65and 95 kDa forms. Clarification of the molecularweight profile of inhibin is importantfor further investigation of the role of inhibinin gonadal functions.In this study, we investigated alterationsin the molecular weight forms of inhibin inbull testis from the infantile to postpubertalperiods. The main findings of our study are:1) inhibins A and B are present in bull testisfrom the infantile to postpubertal periods, 2)infantile bull testis contains a significantamount of the precursor form of inhibins Aand B, 3) the proportion of the mature form(29~32 kDa) of inhibins A and B in the testesof adult bulls markedly increases, and 4)inhibin is exclusively found in Sertoli cellsuntil the postpubertal period (Fig. 10),although the immunoreaction diminished asthe bulls aged.Automatic classification of spotfeature in microarray imageA scratched DNA microarray image andan additive noise of the image reduce theaccuracy in analysis of gene expression. Thegene expression profile is determined basedon the intensity values of the spots inmicroarray. This numerical transformationleads to the loss of the potential informationon the microarray image, and makes it difficultto distinguish scratched spots and additivenoise spots from normal ones. Wepropose the method to detect the scratchedor the additive noise spots automatically,and to eliminate them. The mean, variance,skewness, kurtosis of intensity histogram,and the former statistical characteristics oftwo-dimensional spatial distribution of pixelon each spot are extracted from the microarrayimage. Spots are classified into fourgroups, normal, scratched, ring shaped spotslacking a center area, and additive noisespot, by the statistical characteristics.Support Vector Machines are used as clusteringalgorithm. The proposed method wasapplied to classify 219 spots of rice DNAmicroarray, using 630 spots as training data.The result was that the accuracy on normal,Fig. 10Immunohistochemical localization of inhibin in the testisat 5 wks (a, bar = 25 µm), 32 wks (b) and 50 wks (c) ofage.Counterstaining with hematoxylin was also performed.Arrows indicate Sertoli cells at 50 wks of age.Fig. 11Automatic classification of 219 spots of rice DNA microarray into four groups.Annual Report 2003 65