Differences between rice and wheat in ribulose-1,5-bisphosphate regeneration capacity per unit of leaf-N content

The photosynthetic rates under saturating CO₂ conditions per unit of leaf‐N content were higher in wheat than in rice. This suggested that ribulose‐1,5‐bisphosphate (RuBP) regeneration capacity is greater in wheat. Therefore, the biochemical factor(s) for this difference were examined between rice and wheat. Soluble protein‐N, insoluble‐N, and trichloroacetic acid (TCA) soluble‐N contents were found not to differ between the two species. The activities of several Calvin cycle enzymes such as RuBP carboxylase, NADP‐glyceraldehyde‐3‐phosphate dehydrogenase, phosphoglycerate kinase and chloroplastic fructose‐1,6‐bisphosphatase (cpFBPase) activities per unit of leaf‐N content were all higher in wheat than in rice. Among them, cpFBPase activity was most highly correlated with CO₂‐saturated photosynthesis. The V_max activity of sucrose‐phosphate synthase (SPS) for UDP‐glucose was almost the same between the two species and its K_m value was a little lower in rice. Chlorophyll content and its a/b ratio did not differ. Cytochrome (Cyt) f content was greater in wheat, whereas coupling factor 1 content was greater in rice. Cyt f content was highly correlated with CO₂‐saturated photosynthesis, irrespective of the two species. The results thus suggested that higher RuBP regeneration capacity in wheat leaves is most closely related to a greater Cyt f content and that another candidate is cpFBPase.     

Establishment of a novel dwarf rat strain: cartilage calcification insufficient (CCI) rats

Rats with dwarfism accompanied by skeletal abnormalities, such as shortness of the limbs, tail, and body (dwarf rats), emerged in a Jcl-derived Sprague-Dawley rat colony maintained at the Institute for Animal Experimentation, St. Marianna University Graduate School of Medicine. Since the dwarfism was assumed to be due to a genetic mutation based on its frequency, we bred the dwarf rats and investigated their characteristics in order to identify the causative factors of their phenotypes and whether they could be used as a human disease model. One male and female that produced dwarf progeny were selected, and reproduction was initiated by mating the pair. The incidence of dwarfism was 25.8% among the resultant litter, and dwarfism occurred in both genders, suggesting that it was inherited in an autosomal recessive manner. At 12 weeks of age, the body weights of the male and female dwarf rats were 40% and 57% of those of the normal rats, respectively. In soft X-ray radiographic and histological examinations, shortening and hypoplasia of the long bones, such as the tibia and femur, were observed, which were suggestive of endochondral ossification abnormalities. An immunohistochemical examination detected an aggrecan synthesis disorder, which might have led to delayed calcification and increased growth plate thickening in the dwarf rats. We hypothesized that the principal characteristics of the dwarf rats were systemically induced by insufficient cartilage calcification in their long bones; thus, we named them cartilage calcification insufficient (CCI) rats.     

Minor carotenoid components in the chloroplasts of higher plants

One-dimensional thin layer chromatography with microcrystallinecellulose was used for the separation of minor carotenoid componentsin spinach, parsley and Brassicachloroplasts. It was revealedthat chloroplasts of these plants contain two minor xanthophyllcomponents besides carotenes, lutein, violaxanthin and neoxanthin.These minor components, designated as xanthophyll–443and –439, were different in spectral properties from antheraxanthinand zeaxanthin which are known to be present in the chloroplastsof some higher plants, and evidence was obtained showing thatxanthophyll–439 has an epoxy group. Spectral propertiesof these xanthophylls in benzene, ethanol, H-hexane and carbondisulfide, as well as their contents relative to other carotenoids,are presented in this paper. ¹Postal address     

The accuracy of endometrial cytology in the diagnosis of endometrial adenocarcinoma

tajima m., inamura m., nakamura m., sudo y. and yamagishi k. (1998) Cytopathology 9 , 369–380
The accuracy of endometrial cytology in the diagnosis of endometrial adenocarcinoma
We have examined 62 234 cytological samples of endometrium to establish the accuracy and false-positive rate for the diagnosis of endometrial adenocarcinoma. The patients were either attending the gynaecological out-patients clinic with symptoms or were asymptomatic women attending for routine population screening as part of our cancer detection programme, the numbers from these two sources being equal. Out of 138 cases identified as endometrial adenocarcinoma by cytology 126 (91.3%) were confirmed histologically in our hospital. Twelve cases (8.7%) were shown to be false-positives. Re-examination of these led to the same false-positive diagnosis in all 12 cases. This was attributable to similarities of nucleo–cytoplasmic ratio, irregular arrangement of nuclei, variation in nuclear shape and in the numbers of nucleoli in repair cells and hyperplastic cells compared with the carcinoma cases. Most of the false-negative reports were due to insufficient material, pale staining in malignant cells or diagnostic error. Refraction measurement of the density of nuclei of cancer cells using equipment for which the patent is pending enabled objective measurement of nuclear density which indicated that the nuclei were not stained darkly enough in false-negative cases.