CHANGES OF CELLULAR MORPHOLOGY AND NUCLEAR DNA CONTENT IN DIFFERENT NASOPHARYNGEAL EPITHELIUM FROM DIFFERENT PATIENTS

Cellular morphology and nuclear DNA content were measured with point-counting technique and flow cytometry (FCM) respectively in normal nasopharyngeal epithelium (NE), tissue adjacent to carcinoma (ATC) and nasopharyngeal carcinoma (NPC). The results showed that all 20 patients with NE show ed diploid, whereas 38 (38%) of 101 patients with NPC, 7 (58%) of 12 patients with recurrent NPC, 6 (30%) of 20 patients with ATC and 2 (33%) of 6 patients with NE positive to EBVCA-IgA test showed nondiploid. A total of 19 morphometric parameters of the cell were measured and calculated. The results showed that with malignant transformation of NE, most of the cellular morphometric parameters gradually increased in numerical values while no marked difference was shown between normal NE and simple hyperplasia or metaplasia in terms of cytomorphometric characteristics. Most of the parameters in dysplasia changed significantly as compared with those normal NE, simple hyperplasia or metaplasia and NPC groups. Cytomorphome

Early Morphological and Physiological Events Occurring During Germination of Maize Seeds

The early morphological and physiological events occurring during maize （Zea mays cv. Nongda 108） seed imbibition and germination were studied. Water uptake of seeds exhibited a triphasic pattern with a marked increase during the initial phase of imbibition, and then a slow increase, followed by a second substantial increase. Imbibition time for 10 and 50% of seed germination was about 26 and 46 h at 30℃, respectively. The relative conductivity of maize seeds dramatically decreased during the initial phase of imbibition, followed by a substantial increase. Respiratory rate of seeds gradually increased with imbibition. Length of root cap cells decreased during the initial phase and then increased; those of meristematic zone cells increased during the initial phase and then decreased; and those of elongation zone cells and of the whole elongation zone of the radicle gradually increased during germination. The contents of soluble sugars and starch in embryos gradually decreased as the activities of α- and β-amylase strikingly increased with imbibition. In the meantime, protein contents of embryos gradually decreased and free amino acid content increased. The activities of aminopeptidase and endopeptidase increased until 12 h of imbibition and then decreased. It is concluded that germination of maize seeds is mainly completed by extension of cells in the elongation zone of the radicle, and that mobilization of stored reserves in the embryo during the initial phase of imbibition is also an early event during seed germination.

Comparison of shape representation methods for dynamic cell analysis

To evaluate the performance of basic shape representation methods for the description of dynamic cellular morphology, several frequently-used shape descriptors are compared. The methods are examined by using 50 lymphocyte video clips including two kinds of lymphocyte cells. Our goal is to represent cell shape in each frame accurately, meanwhile precisely classify the two groups of cells based on the cellular morphological variations in the video clips. Experimental results illustrate that in general the region-based shape descriptors outperform the contour-based ones, since the contourbased methods are excessively sensitive and ignorant to cellular internal information. Due to their robustness to noise, the region-based shape descriptors are suitable for dynamic cell representation. Although region-based methods are more time-consuming, they analyze the entire cell area.

Cytological analysis and genetic control of rice anther development

Microsporogenesis and male gametogenesis are essential for the alternating life cycle of flowering plants between diploid sporophyte and haploid gametophyte generations. Rice （Oryza sativa） is the world＇s major staple food, and manipulation of pollen fertility is particularly important for the demands to increase rice grain yield. Towards a better understanding of the mechanisms controlling rice male reproductive development, we describe here the cytological changes of anther development through 14 stages, including cell division, differentiation and degeneration of somatic tissues consisting of four concentric cell layers surrounding and supporting reproductive cells as they form mature pollen grains through meiosis and mitosis. Furthermore, we compare the morphological difference of anthers and pollen grains in both monocot rice and eudicot Arabidopsis thaliana. Additionally, we describe the key genes identified to date critical for rice anther development and pollen formation.