Changes in Metabolite Levels during Growth of Acer pseudoplatanus (Sycamore) Cells in Batch Suspension Culture

Measurements were made of the levels of key glycolytic intermediates and co-factors during the growth of Acer pseudoplatanus L. cells in batch culture. Mass action ratios were calculated for the enzymes phosphoglucoseisomerase, phosphofructokinase and pyruvate kinase. The ratio for phosphofructokinase was greatly displaced from equilibrium. Major increases in the level of NADPH and ATP and energy charge were observed in the initial or lag period of culture. The data indicate that the energy generating system of the cells is most active in the lag phase.     

ONTOGENY OF CHICKEN HEMOGLOBIN. I. ELECTROPHORETIC STUDY OF THE HETEROGENEITY OF HEMOGLOBIN IN DEVELOPMENT

Separation of different molecular species of hemoglobin from developing chickens by starch gel electrophoresis has revealed the appearance of early embryonic (embryonic), late embryonic (fetal) and adult hemoglobin (Hb) type during development. In 5-day embryos, there are 3 or 4 forms of embryonic Hb type. They begin to decrease in 6-day embryos and cannot be detected in embryos after 10 days of incubation. In 6-day embryos, two forms of adult Hb type appear, and one of them, which is a major form in adults, becomes t o be a major one in 7-day embryos. One or two forms of fetal Hb type first appear in 10-day embryos and are still present in 5-day posthatching chickens.
Ultracentrifugation of carbonmonoxyhemoglobins from embryos at early and at later stages (fetuses), from newly hatched and from adult chickens has shown that they have a single monodisperse peak. Some heterogeneity, however, has been detected after starch gel electrophoresis, probably owing to aggregation or polymerization.
Subunit analysis of embryonic, fetal and adult Hb type by starch gel electrophoresis in formate buffer at pH 1.9 has indicated that embryonic Hb type contains total 5 subunits, C, D, E, F and G; fetal Hb type, total 2, A and H; and adult Hb type, total 3, B, F and H.     

Inhibition of Cell Surface Binding of Fibronectin and Fibronectin-Promoted Cell Migration by Synthetic Peptides in Sea Urchin Primary Mesenchyme Cells In Vitro

The role of a site of fibronectin molecule in the cell binding and cell migration was examined in vitro using sea urchin primary mesenchyme cells and synthetic peptides that contain a particular amino acid sequence, Arg-Gly-Asp-Ser.
The binding of fibronectin to the cell surface was inhibited by addition of larger synthetic peptides, Gly-Arg-Gly-Asp-Ser-Pro-Cys (HP) or Arg-Gly-Asp-Ser-Pro-Ala-Ser-Ser-Lys-Pro (DP), but not by a smaller synthetic peptide Gly-Arg-Gly-Asp-Ser (PP). The inhibition was recovered by addition of excess amount of fibronectin to the medium.
The fibronectin-promoted cell migration, by contraries, was conspicuously inhibited by addition of the PP to the cell culture medium which has alrady contained sufficient amount of fibronectin for the migration, but not so obviously by addition of the larger peptides, the HP or the DP. The inhibition was also recovered by addition of excess amount of fibronectin.
These results indicated that fibronectin utilizes Arg-Gly-Asp-Ser in the molecule as an active cell binding and a cell migration promotion site. Slightly different effects seen between the smaller peptide and the larger ones were discussed.     

DEFORMATION MOVEMENT INDUCED BY DIVALENT IONOPHORE A23187 IN THE TUBIFEX EGG

Deformation movement (groove-forming activity of the equatorial surface) was induced in the spherical Tubifex egg by treatment with ionophore A23187 (5–10 μg/ml). The degree of induced movement was maximal when the treatment was commenced at the beginning of the round stages, i.e. , immediately after disappearance of the grooves formed in the preceding normal deformation movement; it gradually decreased as the onset of the treatment was delayed. This induction was independent of either external Ca²⁺ or Mg²+. Ultrastructural examination of eggs undergoing the induced movement revealed the presence of organized microfilaments in the cortical layer of the grooving regions. It is assumed that the absence of contractile activity during the round stages of the Tubifex egg is attributed basically to the low availability of intracellularly stored Ca²⁺. The results also suggest that the distribution and/or the amount of the contractile elements change during these stages.     

CHANGES IN CALCIUM CONCENTRATIONS OF SERUM AND COELOMIC FLUID OF THE BULLFROG, RANA CATESBEIANA, DURING LARVAL DEVELOPMENT AND METAMORPHOSIS

The serum calcium levels of bullfrog tadpoles (stage 26 to 33) and adults are higher than those of the coelomic fluid. The serum levels increase gradually from stage 26 (7.6 mg/100 ml) to stage 30 (8.4 mg/100 ml), and then sharply to stage 33 (10.5 mg/100 ml), while the coelomic fluid levels increase from 7.1 to 8.7 mg/100 ml during this period. Only minor differences are found in serum and coelomic fluid sodium levels among larval stages with the exception of a temporary decrease during metamorphic climax.
These results suggest that the adult type of regulation of serum calcium concentrations is established during larval development and is fully achieved after the completion of metamorphosis. The control mechanism for serum calcium may be different from that for coelomic fluid.     

Encephalitozoon-Like Organisms in Patients with Alveolar Hydatid Disease: Cell Culture, Ultrastructure, Histoimmunochemical Localization and Seroprevalence

ABSTRACT. We found Encephalitozoon -like organisms in an in vitro culture of a human liver lesion which was due to larval Echinococcus multilocularis. The organisms developed in the same fashion as an Encephalitozoon cunculi. The spores that developed in parasitophorous vacuoles were 2.0–2.6 × 1.1–1.5 μm: each contained a single nucleus and 4–5 polar tubule coils, closely resembling E. cuniculi in its ultrastructure. Mature spores were collected from the supernatants by the use of Percoll centrifugation resulting in the banding of the spores on continuous gradients. We prepared three sorts of spores which were different in buoyant density in 0.15 M NaCl: 1.05–1.07 g/ml spores, 1.12 g/ml spores, and spores of over 1.14 g/ml. Polyclonal antibodies to a pool of each spore preparation were produced in a rabbit and applied to the detection of microsporidian antigen in situ. The histoimmunoperoxidase (HIP) procedure was used to detect the microsporidian antigen in echinococcal liver lesions from patients with alveolar hydatid disease (AHD). Ten echinococcal liver lesions from different AHD patients were examined and four were found to be positive in the HIP test. The Percoll-separated spores were also used as an antigen to detect for antibodies in the sera from the patients with AHD by Western blotting. Antibodies were detected in 62 (52%) of the 119 AHD patients and in only 8 (5%) of the 159 normal healthy individuals.     

Carotenoid and Steroid Syntheses by Carrot Cells in Suspension Culture

Biosynthesis of carotenoids and steroids in tissue cultures of carrot cells I Daucus carota L.) was studied by measuring the change in their contents and incorporation of ^14lC-acelate. The rate of synthesis of these plant products varied significantly during the growth cycle in batch culture. Carotenoids were most actively synthesized in the early logarithmic phase and the synthetic rate sharply declined as the culture aged, whereas the rate of accumulation of phytosterols was highest at the end of the growth phase. Newly synthesized carotenes were shown to undergo turnover during the growth. The synthesis of both carotecnoid and steroid was stimulated by 2.- 4-dichlorophenoxyacetic acid.     

华北二月兰-春玉米轮作体系中土壤硝态氮的时空变化特征

二月兰-春玉米轮作生产体系是近年来为解决华北地区出现的大面积冬闲田而提出的冬绿肥-春玉米生产新模式.本文依托定位试验,研究了该体系从二月兰翻压到玉米收获期间的土壤硝态氮时空变化特征.结果表明：土壤硝态氮含量呈玉米生育前期高后期低的时间变化特征和硝态氮含量峰值随着生育期的推移逐渐下移的空间变化特征,且土壤硝态氮含量随施肥量的增加而显著增加.翻压二月兰对土壤硝态氮含量的时空变化有一定影响,冬春季种植二月兰可降低0～180 cm土壤硝态氮累积量;二月兰翻压后,春玉米苗期与喇叭口期土壤硝态氮规律基本一致,主要集中在0～20 cm土层,0～100 cm土壤剖面为有二月兰处理高于无二月兰处理,100～180 cm土壤剖面则为有二月兰处理低于无二月兰处理;抽雄期以后,土壤硝态氮含量普遍较低,100～180 cm土层土壤硝态氮含量为有二月兰处理略高于无二月兰处理.总体上,翻压二月兰可以增加0～180 cm土层土壤硝态氮保蓄量.