Vertical distributions of viable (most probable number, MPN) aerobic chemoautotrophic thiobacilli-like sulfur-oxidizing bacteria (ca. 70 samples in triplicate for MPN counts) and dark 14Cbicarbonate incorporation rates were analyzed in a series of sulfide-rich lakes. A special device for sampling sharply stratified populations on the scale of a few centimeters was used. Detailed analyses focuse...

© Rzepa This article is distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and redistribution in any medium, provided that the original author and source are credited. Ribulose-1,5-bisphosphate reacts with carbon dioxide to produce 3-keto-2carboxyarabinitol 1,5-bisphosphate as the first step in the biochemical...

To evaluate leaf carbon balance during rapid pod-fill in soybean (Glycine max [L.] Merrill), measurements were made of CO(2) assimilation at mid-day and changes in specific leaf weight, starch, and sucrose concentrations over a 9-hour interval. Assimilate export was estimated from CO(2) assimilation and leaf dry matter accumulation. Chamber-grown ;Amsoy 71' and ;Wells' plants were subjected on ...

The isotope pattern found in rat liver glycogen following administration of a variety of carbon-labeled compounds has been used by Wood and his coworkers (l-6) in studies concerning carbon metabolism. Experiments of a similar nature involving glutamic acid as the target molecule will be described in this paper. Its relative abundance, ease of isolation, and interconversion in ti~o with cY-ketog...

Chemoautotrophic symbioses, in which endosymbiotic bacteria are the major source of organic carbon for the host, are found in marine habitats where sulfide and oxygen coexist. The purpose of this study was to determine the influence of pH, alternate sulfur sources, and electron acceptors on carbon fixation and to investigate which form(s) of inorganic carbon is taken up and fixed by the gamma-p...

Nitrogenase (EC 1.7.99.2) activity of nodules of cowpea (Vigna unguiculata [L.] Walp), maintained under conditions of a 12-hour day at 30 degrees C and 800 to 1,000 microeinsteins per square meter per second (photosynthetically active radiation) and a 12-hour night at 20 degrees C, showed a marked diurnal variation with the total electron flux through the enzyme at night being 60% of that in th...

Hormonal control of the initial step in hepatic gluconeogenesis from pyruvate was examined following acute administration of epinephrine, glucagon, or cortisol to adult rats. After hormonal treatment of the animals, the mitochondria were isolated for the study of pyruvate metabolism. When pyruvate and bicarbonate were the only substrates provided, mitochondrial fixation of carbon dioxide and pr...

Oceanic crust is a massive potential habitat for microbial life on Earth, yet our understanding of this ecosystem is limited due to difficulty in access. In particular, measurements of rates of microbial activity are sparse. We used stable carbon isotope incubations of crustal samples, coupled with functional gene analyses, to examine the potential for carbon fixation on oceanic crust. Both sea...