Ribulose 1,5-diphosphate carboxylase has been isolated from autotrophically cultured Rhoclospirillum rubrum. The molecular weight is 120,000. The K, for ribulose 1,5diphosphate is 83 mM, and for CO2 is 59 mM. The enzyme is inhibited by three important metabolites: citrate, an intermediate of the tricarboxylic acid cycle; inorganic phosphate; and 3-phosphoglyceric acid, the product of the reacti...

The coating of solid-binding peptides (SBPs) on inorganic material surfaces holds significant potential for improved surface functionalization at nano-bio interfaces. In most related studies, the goal has been to engineer peptides with selective and high binding affinity for a target material. The role of the material substrate itself in modulating the adsorption behavior of a peptide molecule ...

To investigate the impact of organic N compounds for inorganic nitrogen uptake in the rhizosphere, we fed ammonium nitrate with or without amino acids (i.e., glutamine or arginine) to the roots of non-mycorrhizal beech (Fagus sylvatica L.) seedlings under controlled conditions at different levels of N availability. Uptake of individual N sources was determined from ¹⁵N (inorganic N) and ¹⁵N ¹³C...

The biogeochemical composition of 2 spatially separate surface gap layers on a single Antarctic sea ice floe during early austral summer was predominantly controlled by the growth of diatoms and, especially, Phaeocystis. These algal communities in and near the gap layers imposed large geochemical changes in the chemical and isotopic composition of the gap waters, typical of intense autotrophic ...

Since the heydays of Reactive Sulfur Species (RSS) research during the first decade of the Millennium, numerous sulfur species involved in cellular regulation and signalling have been discovered. Yet despite the general predominance of organic species in organisms, recent years have also seen the emergence of inorganic reactive sulfur species, ranging from inorganic polysulfides (HSx-/Sx2-) to ...

Phosphatidic acid phosphohydrolase (3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4), also known as PAP, catalyzes the dephosphorylation of phosphatidic acid (PtdOH) to form diacylglycerol (DAG) and inorganic orthophosphate. In eukaryotes, the PAP driven reaction is the committed step in the synthesis of triacylglycerol (TAG). Existing methods for measuring PAP activity rely on the use of radio...

The goal of the present study was to compare the arsenic methylation capacities in elementary school and junior high school students in an area of Taiwan with low arsenic exposure, and explore the influence of both arsenic methylation capacity and obesity on insulin resistance in these children and adolescents using the HOMA-IR index. We recruited 303 elementary school students and 319 junior h...

Background. Industrial processing of the pecan nut Carya illinoinensis K. Koch generated a large amount of shells, which have been used to prepare nutritional supplements and medicinal products; however, the safe use of shells requires assessment. This study evaluated the toxic, genotoxic, and mutagenic effects of pecan shell aqueous extract (PSAE) and the possible contribution of phenolic comp...

The effects of nitrate and ammonium addition on net and gross photosynthesis, CO(2) efflux and the dissolved inorganic carbon compensation point of nitrogen-limited Selenastrum minutum Naeg. Collins (Chlorophyta) were studied. Cultures pulsed with nitrate or ammonium exhibited a marked decrease in both net and gross photosynthetic carbon fixation. During this period of suppression the specific ...

The influence of gastric juice on iron absorption has been studied extensively in recent years. The absorption of haemoglobin iron is unaffected by achlorhydria (Biggs, Bannerman, and Callender, 1962) but inorganic iron is better absorbed in the presence of normal gastric juice (Goldberg, Lochhead, and Dagg, 1963; Cook, Brown, and Valberg, 1964). It has been shown that the administration of hyd...