Matter production processes ofReineckia carnea Kunth,an evergreen forest floor herb in the warm-temperate region of Japan

The growth and matter production were examined forReineckia carnea, an evergreen herb growing on the forest floor in a warm-temperate region. Seasonal change in the biomass of plants growing in the field was estimated from the harvested sample plants. Carbohydrate contents and respiration rates were measured for analysis of dry matter economy. Light intensity and temperature on the forest floor were periodically measured. In mid-spring the biomass reached a maximum which was about half again its minimum value, found in autumn. Two phases, the productive phase in cooler seasons and the developmental phase in warmer seasons, were distinguished from the annual growth pattern of this plant. In cooler seasons, positive net production was found without any morphological changes, resulting in active accumulation of reserves which were mainly soluble sugars. This high net production seems to be closely related to the favorable light conditions and low respiratory losses. In warmer seasons, though new organs were developed, net production remained low or was even negative. The morphological development of this plant in these seasons depended mostly on reserves previously accumulated. This characteristic feature of annual matter economy is considered to be common to evergreen plants on the forest floor in warm regions.     

Electromagnetic mediated pharmacokinetics in a three-layer diffusional system

The effect of an applied electromagnetic field on drug diffusion in a one dimensional, three-layer drug-receptor model has been analyzed and expressed in terms of a normalized turnover rate parameter. The analysis reveals that an imposed harmonic time-varying electromagnetic field may enhance or retard the drug turnover rate depending on the diffusional pattern, the equivalent Michaelis constant, the maximum drug turnover rate of the intrinsic drug-receptor system, as well as the power density and frequency of the applied electromagnetic field. It is estimated that the power density in the order of magnitude of 1μW/cm² at 100 MHz frequency range may be required to induce significant rate effects.     

Nitrogen fixation by immobilized Azotobacter chroococcum

A nitrogen-fixing bacterium, Azotobacter chroococcum, was immobilized in 2% agar gel. The optimum partial oxygen pressure, pO₂, of immobilized cells was 0.2 atm, wherea s that of native cells was 0.05 atm. When continual nitrogen fixation was performed under aerobic conditions, the nitrogenase activity of immobilized cells increased with increasing time. On the other hand, the activity of native cells decreased rapidly. Increase of nitrogenase activity was attributed to growth of the bacteria in the gel matrix. The production rate of total nitrogen compounds by the immobilized bacteria was also increased during the first 4 days. Nitrogen compounds produced by the immobilized cells were mainly amino acids such as γ-aminobutyrate, glutamate and arginine.     

Circadian alterations in tubular structures on the outer mitochondrial membrane of rat hepatocytes

Summary The ontogeny and distribution of immunoreactive motilin and secretin were studied in the gastro-entero-pancreatic (GEP) system of human fetuses, aged 5–24 weeks, using an indirect immunocytochemical method. Several controls to check for the specificity of the immunoperoxidase staining were performed. The first motilin- and secretin-containing cells were observed in the duodenal and jejunal mucosa in fetuses at a gestational age of 16 weeks. These immunoreactive cells were located in the glands of Lieberkühn and in the villi. No immunoreactive cells were present in the oxyntic and pyloric mucosa, ileum, colon and endocrine pancreas. These observations indicate that the motilin- and secretin-containing cells detected by our antisera appear (i) in the same organs of the fetus where they are also detectable in the adult, and (ii) after the completion of histogenesis of the gastro-entero-pancreatic (GEP) system.     

Effects of purine nucleotides on photosynthetic electron transport in isolated chloroplasts

The effects of guanylates and inosinates (and adenylates) on phosphorylation, ferricyanide reduction, and light-induced H⁺ uptake in spinach chloroplasts were studied. GDP, GTP, IDP, and ITP (but not GMP and IMP) stimulated the light-induced H⁺ uptake and partially inhibited ferricyanide reduction. Phosphate, arsenate, and phlorizin increased the extent of inhibition by these nucleotides and decreased the values of their apparent dissociation constants for the inhibition process. In the presence of phosphate (or arsenate), restoration of ferricyanide reduction from the level inhibited by guanylates and inosinates was observed as phosphorylation (or arsenylation) proceeded. These results suggest that phosphorylation of GDP and IDP as well as ADP takes place after two steps of nucleotide binding to the chloroplast coupling factor 1. The apparent dissociation constants of GDP and IDP for these two binding steps were estimated to be about 34 and 38 µM for the first and 110 and 160 µM for the second step, respectively (at pH 8.3, 15°C). Above pH 9, the ratio (P/e) of the extent of phosphorylation to the increment of electron transport from the basal level measured in the presence of [ATP + Pi] or [ADP + Pi + phlorizin], became increasingly large. When the electron transport level inhibited by dicyclohexylcarbodiimide was taken to be the basal activity, the P/e ratio remained almost constant ( 1) from pH 7.0 up to 10.     

Purification and characterization of phosphoenolpyruvate phosphomutase from Pseudomonas gladioli B-1.

Phosphoenolpyruvate phosphomutase (PEPPM) catalyzes C-P bond formation by intramolecular rearrangement of phosphoenolpyruvate to phosphonopyruvate (PnPy). We purified PEPPM from a gram-negative bacterium, Pseudomonas gladioli B-1 isolated as a C-P compound producer. The equilibrium of this reaction favors the formation of the phosphate ester by cleaving the C-P bond of PnPy, but the C-P bond-forming reaction is physiologically significant. The C-P bond-forming activity of PEPPM was confirmed with a purified protein. The molecular mass of the native enzyme was estimated to be 263 and 220 kDa by gel filtration and polyacrylamide gel electrophoresis, respectively. A subunit molecular mass of 61 kDa was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that the native protein was a tetramer. The optimum pH and temperature were 7.5 to 8.0 and 40 degrees C, respectively. The Km value for PnPy was 19 +/- 3.5 microM, and the maximum initial velocity of the conversion of PnPy to phosphoenolpyruvate was 200 microM/s/mg. PEPPM was activated by the presence of the divalent metal ion, and the Km values were 3.5 +/- 1.4 microM for Mg2+, 16 +/- 5 nM for Mn2+, 3.0 +/- 1.5 microM for Zn2+, and 1.2 +/- 0.2 microM for Co2+.     

A child with pituitary gigantism and precocious adrenarche: does GH and/or PRL advance the onset of adrenarche?

We describe a female child with pituitary gigantism and precocious adrenarche. From two years of age she showed unusual overgrowth, and at 5 years old she was 133.5 cm (+ 5.5 SD) tall and weighed 40.5 kg. Her precocious manifestations were public hair, acne vulgaris, hirsutism, and advanced bone age. Endocrinological examination revealed markedly increased serum growth hormone (GH) and prolactin (PRL), which responded paradoxically to a TRH test. In addition, the concentrations of serum dehydroepiandrosterone (DHA) and its sulfate (DHAS) were increased to adult levels, moving in accordance with changes in ACTH, which suggested that these androgens were secreted from the adrenal glands functionally. These androgens seemed to be responsible for her partial precocity. Prior reports have suggested that GH and/or PRL overproduction might have played a role in the induction of adrenarche. Also, in previous reports of 9 gigantism patients under 10 years old, the manifestation of precocious adrenarche was suggested in 8. Further investigation of the influence of GH and PRL on adrenal androgen production in children with pituitary gigantism is required. On the other hand, in short children with normal GH secretion, attention should be paid to whether or not the GH therapy in early childhood induces precocious adrenarche.     

Parturition in a free-ranging Japanese monkey (Macaca fuscata)

Parturition behavior of a multiparous female and her interactions with group members throughout the birth process were recorded for a free-ranging Japanese monkey (Macaca fuscata). The female showed evidence of 18 contractions during the 35 min prior to delivery, with a mean duration and a mean intercontraction interval of 30 sec and 96 sec, respectively. These values were similar to those in individually caged Japanese monkeys. Some adult females remained in proximity to the female who was giving birth during the prepartum phase, and her 2-year-old daughter watched the delivery of the infant. Even during the prepartum phase the female moved in order to keep up with the group which traveled from the feeding site to a sleeping site in the forest.     

A new structural model for the thyrotropin (TSH) receptor, as determined by covalent cross-linking of TSH to the recombinant receptor in intact cells: evidence for a single polypeptide chain.

The most widely held model for the human TSH receptor is of holoreceptor of 80 kDa with two subunits of approximately 50 and 30 kDa linked by disulfide bridges, with the former subunit containing the major hormone-binding site. We reexamined this model by covalently cross-linking radiolabeled TSH to the recombinant human TSH receptor stably expressed in Chinese hamster ovary (CHO) cells. When cross-linking was performed after the preparation of CHO membranes, analysis of hormone-receptor complexes under reducing and nonreducing conditions provided results supporting the two-subunit TSH receptor model. In contrast, however, cross-linking of TSH to the TSH receptor in intact CHO cells before membrane preparation revealed, even under reducing conditions, an approximately 100-kDa receptor as well as an approximately 54-kDa hormone-binding subunit. The approximately 100-kDa holoreceptor size is consistent with the size of the TSH receptor, as predicted from its derived amino acid sequence. The proportions of the approximately 100-kDa TSH receptor and the 54-kDa fragment varied in different experiments, suggesting the occurrence of proteolytic cleavage. Cross-linking of radiolabeled TSH to intact cells expressing a mutant TSH receptor (TSHR-D1) lacking amino acids 317-366 localized the proteolytic cleavage site to just up-stream of amino acid residue 317. In summary, the present data obtained by cross-linking TSH to recombinant human TSH receptors in intact cells provides evidence that the receptor exists in vivo as an approximately 100-kDa glycoprotein with a single polypeptide chain with intramolecular disulfide bridges.(ABSTRACT TRUNCATED AT 250 WORDS)