Acetone degradation by cell suspensions of Desulfococcus biacutus was CO2 dependent, indicating initiation by a carboxylation reaction, while degradation of 3-hydroxybutyrate was not CO2 dependent. Growth on 3-hydroxybutyrate resulted in acetate accumulation in the medium at a ratio of 1 mol of acetate per mol of substrate degraded. In acetone-grown cultures no coenzyme A (CoA) transferase or C...

Vitamin K-dependent (VKD) proteins require modification by the VKD-gamma-glutamyl carboxylase, an enzyme that converts clusters of glus to glas in a reaction that requires vitamin K hydroquinone, for their activity. We have discovered that the carboxylase also carboxylates itself in a reaction dependent on vitamin K. When pure human recombinant carboxylase was incubated in vitro with 14CO2 and ...

Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO(2) co...

TADA, K. and ARAKAWA, Ts. Hyperglycinemia and propionate carboxylation. Tohoku J. exp. Med., 1970, 102 (3), 313-314 The oxidation of propionate and methylmalonate was investigated in leukocytes from a patient with hyperglycin emia. It was found that the patient's leukocytes could oxidize both propionate and methylmalonate normally. These findings suggest that hyperglycinemia con sists of primar...

Technical Papers Relation of Prothrombin to the Prolongation of Clotting Timiie in Aestivating Ground Squirrels: Arthur Svihla, Howard Bowman, and Ruth Ritenour . ............................... 306 Inactivation of Influenza Virus and of Viral Hemiiagglutinin by the Ciliate Tetrahymena geleii: Vincent Groupe' and Leonora H. Pugh........ . ........... ... . 307 The Importance of Protective Urina...

Generally, primed seeds produce larger and heavier plants than non-primed seeds. This may be simply due to rapid emergence and extension of leaf growth, or the influence of other physiological processes. The effect of seed pretreatment with salicylic acid (SA) on some physiological and photosynthetic characteristics of the safflower seedlings, cv. Goldasht, was examined under field condition. T...

The content of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (Et; EC 4.1.1.39) measured in different-aged leaves of sunflower (Helianthus annuus) and other plants grown under different light intensities, varied from 2 to 75 &mgr;mol active sites m-2. Mesophyll conductance (&mgr;) was measured under 1.5% O2, as well as postillumination CO2 uptake (assimilatory charge, a gas-exchange ...

There has been much interest in the chloroplast-encoded large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) as a target for engineering an increase in net CO(2) fixation in photosynthesis. Improvements in the enzyme would lead to an increase in the production of food, fiber, and renewable energy. Although the large subunit contains the active site, a family of rbcS nuclea...

BACKGROUND AND AIMS Elucidation of the mechanisms by which plants adapt to elevated CO2 is needed; however, most studies of the mechanisms investigated the response of plants adapted to current atmospheric CO2. The rapid respiration rate of cotton (Gossypium hirsutum) fruits (bolls) produces a concentrated CO2 microenvironment around the bolls and bracts. It has been observed that the intercell...

It is important to understand how eco-physiological characteristics shift in forests when elucidating the mechanisms underlying species replacement and the process of succession and stabilization. In this study, the dominant species at three typical successional stages (early-, mid-, and late-succession) in the subtropical forests of China were selected. At each stage, we compared the leaf cons...