The Gift in Sixteenth-Century France

The Gift in Sixteenth-Century France . Natalie Zemon Davis. Madison: University of Wisconsin Press. 2000. 196 pp.     

Estimating the beginning day of Japanese cedar pollen release under global climate change

This study examined the effects of snowfall on the beginning day of Cryptomeria japonica pollen release and predicted it under global climate change. We used a statistical method in order to investigate when the pollen release would start and how much sooner it would be, by using data on predicted meteorological conditions under global warming in Yamagata City, Japan. Estimation accuracy was improved by multiple regression by using the mean air temperature from January to February and snowfall depth in February. Adding snowfall depth yielded more accurate estimates of the beginning day of pollen release than using air temperature alone. It is possible that the effects of heat insulation and cooling by snow delay the flowering day. Under the predicted global climate change, we expect the beginning day of pollen release to become earlier in Yamagata City. The date would be 8 February in approximately 100 years, compared with 20 February at the earliest now. Eighty years from now the date could be earlier than any date recorded so far.     

Stimulation of Protein Synthesis in the Mitochondria of Sea Urchin Embryos before Gastrulation

A transient increase in protein synthesis was observed in mitochondria at the mesenchyme blastula stage of sea urchin ( Hemicentrotus pulcherrimus ) embryos. This stimulated activity was inhibited by chloramphenicol but not by cycloheximide. Reconstituting experiments in which poly U-dependent protein synthesis was carried out showed the mitochondrial peptide elongation factor to be essential for increasing the protein synthetic activity in mesenchyme blastula, but aminoacyl tRNA synthetase and ribosome fraction containing initiation factor not to be involved in this increase. These findings are discussed in relation to the differentiation of embryos at the gastrulation stage.     

STUDIES ON PROTEIN METABOLISM IN HIGHER PLANTS. III. CHANGES IN THE SOLUBLE PROTEIN COMPONENTS WITH LEAF GROWTH

Water soluble protein was extracted from tobacco leaves (BrightYellow) and fractionated through chromatographic and immunochemicalprocedures. Six different UV-absorbing components, 7 antigeniccomponents, and 4 enzyme activities (phosphatase, protease,peroxidase and RNase) were detected on the Sephadex chromatogramsof leaf extracts. An UV-absorbing fraction, Fr. I-2, (immunochemicallydesignated as Pr. Imm-I) corresponded to the known "FractionI " of S. G. WILDMAN. The contents of the three antigenic components,Imm-a, Imm-b and Imm-c, having estimated molecular weights of1 to 2 10⁵, showed significant fluctuations during growthof the leaves. Peroxidase and another antigenic component (Imm-f)of smaller molecular weight showed increase with age of theleaves. Properties of the protein components thus detected wereinvestigated. (Received May 11, 1967; )     

Action Spectrum for Photoactivation of the Water-splitting System in Plastids of Intermittently Illuminated Wheat Leaves

The chloroplasts from wheat leaves developed under intermittent illumination (1 ms light + 12 min dark) were able to photoreduce DPIP with DPC as electron donor but unable to photoreduce DPIP with water as electron donor. On exposure of these leaves to continuous light, the Hill activity with water as electron donor was rapidly induced. The photoactivation was sensitive to the treatment with DCMU prior to exposure to continuous light. The action spectrum for the photoactivation showed a sharp band at 680 nm with a distinct shoulder at 650 nm, and was similar to the absorption spectrum of photosytem-2 particles. These data suggest that the electron transfer driven by photosystem 2 is essential for the activation of the water-splitting system in the chloroplasts of intermittently illuminated leaves.     

Arginine Vasopressin Contents of the Hypothalamus and Pituitary during Fetal and Postnatal Development in the Mouse

The contents of arginine vasopressin (AVP) in the hypothalamus and the pituitary of the mouse during fetal and postnatal development were measured by radioimmunoassay. AVP was first detected in the hypothalamo-pituitary system at the fetal age of 14 days (FA 14). After FA 15, the pituitary levels were higher than the hypothalamic levels except on FA 16. The greater AVP content of the hypothalamus than the pituitary only on FA 16 suggests that AVP synthesis in the perikarya of AVP-producing neurons may significantly increase between FA 15 and FA 16, and that the hormonal transport to the pituitary may be characteristically activated between FA 16 and FA 17. The levels of AVP in both the hypothalamus and the pituitary increased exponentially until the postnatal age of 21 days (PA 21). After PA 30, the content in the pituitary continued to increase, while that in the hypothalamus was kept almost constant. The decrease in AVP content in the pituitary was found between PA 0 and PA 1, and PA 21 and PA 30. These results suggest that AVP might be released from the pituitary in response to significant changes in water metabolism elicited at birth and weaning.     

STUDIES ON PROTEIN METABOLISM IN HIGHER PLANTS IV. CHANGES IN PROTEIN COMPONENTS IN DETACHED LEAVES OF TOBACCO

Soluble protein fractions from tobacco leaves before and aftercuring were compared. The results of Sephadex G-200 or G-75chromatography and immunological experiments showed that theamount of larger molecular weight proteins diminished or greatlydecreased and that smaller molecular weight proteins accumulatedduring 3 days at 40 and 90% humidity after excision of theleaves from the stem. Fraction I, which was the largest proteinin the leaf extract and occupied about one-half of the solubleprotein before curing, was not found in the proteins after curing.On the contrary, the proteins contained in II-4 fraction, whichwere supposed to have smaller molecular weights, increased three-foldduring the curing. The origin of the smaller proteins was discussed. (Received May 11, 1967; )