Nitrification and nitrogen accumulation in the early stages of primary succession on Mt. Fuji

The relationship between nitrification potential and nitrogen accumulation was studied in an early successional sere on Mt. Fuji. Soil organic nitrogen accumulated with the invasion ofPolygonum cuspidatum and successively withMiscanthus oligostachyus and other species. Laboratory incubation experiments showed a higher nitrification potential at theM. oligostachyus state. The numbers of nitrifying bacteria increased with the progress of succession. No significant difference in nitrate reductase activity was found between pioneer and succeeding species. The soil solution at theM. oligostachyus stage contained a lower level of nitrate than rainwater, while that of the bare ground and theP. cuspidatum stage contained a higher nitrate level than rainwater. It was concluded that the high nitrate levels in the soil solution of the bare ground and theP. cuspidatum stage were due to lower nitrate-absorbing activity, leading to loss of nitrogen with precipitation, while the lower nitrate levels at theM. oligostachyus stage when higher nitrification activity occurred were due to higher nitrate-absorbing activity, preventing net loss of nitrogen from the ecosystem.     

Heavy chain of human high molecular weight and low molecular weight kininogens binds calcium ion

An antibody subpopulation, anti high molecular weight (anti-HMW) kininogen-Ca2+ antibody able to bind specifically to the HMW kininogen-Ca2+ complex, was isolated from anti-HMW kininogen antiserum. Partially purified anti-HMW kininogen antibody was applied to a HMW kininogen-Sepharose column equilibrated with 40 mM tris(hydroxymethyl)aminomethane hydrochloride buffer, pH 7.5, containing 1.0 M NaCl and 1 mM CaCl2, and anti-HMW kininogen-Ca2+ antibody was eluted with 5 mM ethylenediaminetetraacetic acid. As a result of characterization by enzyme-linked immunosorbent assay, this antibody specifically recognized the cyanogen bromide cleaved fragment 1 (CB-1) region (1-160 amino acid sequence) of the heavy chain of kininogen molecules in the presence of Ca2+ or Mg2+. Furthermore, circular dichroism (CD) experiments showed that the conformational changes of HMW kininogen and heavy chain were induced by metal ions such as Ca2+ and Mg2+ and that these changes were due to the conformational change of the CB-1 region of the heavy chain. The dissociation constant (Kd) for the heavy chain-Ca2+ measured by CD analysis at 214 nm was found to be 0.33 +/- 0.09 mM (mean +/- SD). The number of Ca2+-binding sites of heavy chain calculated from the Hill plot was 1.15 +/- 0.04 (mean +/- SD). Then, a possible Ca2+-binding site was found in the amino-terminal portion of the heavy chain of kininogen molecules.     

Enhancement of the actin-activated ATPase activity of myosin from canine cardiac ventricle by purealin

The effects of purealin isolated from the sea sponge, Psammaplysilla purea, on the enzymatic properties of myosin and natural actomyosin (a complex of myosin, actin, tropomyosin and troponin) from canine cardiac ventricle were studied. Purealin increased the ATPase activity of natural actomyosin and the actin-activated ATPase activity of myosin, and accelerated the superprecipitation of natural actomyosin. The Ca2+- and Mg2+-ATPase activities of myosin were inhibited by purealin, whereas the K+-EDTA-ATPase activity was increased. These results suggest that purealin binds to the myosin portion involved in actin-myosin interaction and increases the actin-activated ATPase activity of myosin.     

Growth inhibitory and lethal effects of ethanol on Escherichia coli

The growth inhibitory and lethal effects of ethanol on Escherichia coli BB were investigated in batch cultures, by measuring total cell number, viable cell number, and cell mass concentration. Ethanol below ca. 50 g/L allowed exponential growth but depressed the specific growth rate. The effect of ethanol on the specific growth rate appeared to follow noncompetitive inhibition kinetics with apparently cooperative binding with a Hill coefficient of 2.5. The Hill coefficient and the inhibition constant were temperature independent over the range tested. Ethanol at 30 g/L decreased the growth yield. Ethanol enhanced the specific death rate in an experimental way. Stationary cell populations were more resistant than exponential ones but the degree of enhancement by ethanol was the same in both populations. Isopropanol and propanol also enhanced the specific death rate exponentially and the degree of enhancement was correlatedwith their membrane-buffer partition coefficients.     

A case of von Recklinghausen's disease associated with pheochromocytoma and papillary carcinoma of the thyroid gland

A 58-year-old woman was admitted to our hospital complaining of headache, dizziness and intermittent elevation of blood pressure. Multiple café-au-lait spots and neurofibromas had appeared on the back and the limbs since the age of 30 years. At the age of 54 years she underwent total thyroidectomy because of papillary carcinoma of the thyroid gland. On admission, the levels of plasma norepinephrine and epinephrine, urinary norepinephrine and normetanephrine were all within the normal range. However, urinary excretion of metanephrine was markedly increased to 1.49 +/- 0.45 (Mean +/- SD) mg/day and that of epinephrine was also slightly increased. The computed tomographic scans of the abdomen and the scintigraphy with 131I-metaiodobenzylguanidine revealed a tumor mass in the region of the right adrenal gland. The tumor was histologically confirmed to be pheochromocytoma at the operation. In her family history, her mother and one of her two sisters had von Recklinghausen's disease and another sister suffered from follicular carcinoma of the thyroid gland. As far as we know, this paper is the first report of a patient with von Recklinghausen's disease associated with both pheochromocytoma and non-medullary carcinoma of the thyroid gland, and her family.     

Nucleotide sequence of a cellulase gene of Bacillus subtilis

The nucleotide sequence of an endolytic cellulase gene of Bacillus subtilis was determined and compared with the NH2-terminal amino acid sequence of the purified enzyme. The mature protein appeared to be extended by a signal sequence of 36 amino acids. The putative AUG initiation codon was preceded by a sigma 43-type promoter of B. subtilis and an AAGGAGG sequence, typical of procaryotic ribosomal binding sites. Partial homology of amino acid sequences was found between B. subtilis cellulase and an alkalophilic Bacillus cellulase.     

Purification of substrate proteins of casein kinases from the cytosol fraction of AH-66 hepatoma cells

We have attempted to purify endogenous substrate proteins for casein kinases I and II from the cytosol of AH-66 hepatoma cells. Utilizing the fact that only a few substrates are concentrated in the fraction eluted from DEAE-cellulose between 0.3 and 0.6 M NaCl, two substrates were purified from this fraction by DEAE-cellulose chromatography, hydroxyapatite chromatography, and HPLC on a DEAE-5PW column. The purified substrate proteins had molecular masses of 30.5 kDa and 31 kDa. The 31-kDa protein substrate was markedly phosphorylated by casein kinase II, but only slightly by casein kinase I. The radioactive phosphate incorporated into 31-kDa substrate by casein kinase II was 0.2 mol/mol of the protein and phosphorylation occurred on both threonine and serine residues. The 30.5 kDa protein was only slightly phosphorylated by casein kinase II, but not at all by casein kinase I.