Search results for " respiration"

Plant litter decomposition and microbial characteristics in volcanic soils (Mt Etna, Sicily) at different stages of development

2006

Soils at different developmental stages were sampled from eight sites on the slopes of Mt Etna, Sicily (Italy) and characterized for total C, microbial biomass and microbial respiration. The values of these parameters were greatest for the most developed soils, but differences in recent management and site characteristics limited analysis of trends with soil development across the eight sites. The decomposition kinetics of both intact leaf litter and the water-insoluble fraction of leaf litter from three common species on Etna [Etnean broom (Genista aetnensis), European chestnut (Castanea sativa), and Corsican pine (Pinus nigra)] were determined in four of the soils (the two with the smalle…

Ecological indicators – Schrödinger Ratio

2008

In situ polymerization of soil organic matter by oxidative biomimetic catalysis

2017

Abstract Background Agricultural practices that enhance organic matter content in soil can play a central role in sequestering soil organic carbon (SOC) and reducing greenhouse gases emissions. Methods We used a water-soluble iron-porphyrin to catalyze directly in situ oxidative polymerization of soil organic matter in the presence of H2O2 oxidant, with the aim to enhance OC stabilization, and, consequently, reduce CO2 emissions from soil. The occurred SOC stabilization was assessed by monitoring soil aggregate stability, OC distribution in water-soluble aggregates, soil respiration, and extraction yields of humic and fulvic acids. Results Soil treatment with H2O2 and iron-porphyrin increas…

Maternal and perinatal outcomes of pregnant women with SARS-CoV-2 infection

2021

WOS:000613461600006 PubMed ID: 32926494 Objectives To evaluate the maternal and perinatal outcomes of pregnancies affected by SARS-CoV-2 infection. Methods This was a multinational retrospective cohort study including women with a singleton pregnancy and laboratory-confirmed SARS-CoV-2 infection, conducted in 72 centers in 22 different countries in Europe, the USA, South America, Asia and Australia, between 1 February 2020 and 30 April 2020. Confirmed SARS-CoV-2 infection was defined as a positive result on real-time reverse-transcription polymerase chain reaction (RT-PCR) assay of nasopharyngeal swab specimens. The primary outcome was a composite measure of maternal mortality and morbidity…

Modulation of tumor oxygenation

1998

There is a large body of evidence suggesting that deficiencies in the O2 supply of tumors exist due to restrictions (i) in the O2 delivery by perfusion and/or diffusion, and (ii) in the O2 transport capacity. Whereas the former are mostly based on inadequate and heterogeneous microcirculatory functions, the latter are predominantly due to tumor-associated anemia. Possible uses and limitations of measures are discussed which can increase the microvascular O2 content and thus may preferentially serve to enhance diffusion-limited O2 availability. In addition, means are described for improving and increasing the uniformity of microcirculation thus possibly enhancing perfusion-limited O2 deliver…

Validating an apple dry matter production model with whole canopy gas exchange measurements in the field

1999

The simplified apple dry matter production model developed by Lakso and Johnson (1990) was modified by inputing tree-specific parameters from a study of seasonal growth and gas exchange of 4-year-old Empire/M.9 apple trees, and light and temperature response curves developed for Empire apple organs. Measurements of the seasonal trend of diurnal net C02 and canopy water vapor exchange were made at intervals on three four-year-old 'Empire'/M.9 slender spindle apple trees in the orchard from 10 days after bloom until 25 days after harvest. The tree canopies were enclosed in clear plastic "balloon- type" chambers (similar to Corelli and Magnanini, 1993) that was monitored continuously for more …

Evaluating carbon fluxes in orange orchards in relation to planting density

2009

SUMMARYOrange (Citrus sinensis L.) is one of the main fruit crops worldwide and its evergreen orchards may have a great potential for carbon (C) sequestration, but no data are currently available. In order to understand carbon fluxes in orange orchards, an experiment was undertaken on traditional and intensive planting systems.The experiment used C. sinensis scions grafted onto Citrus aurantium (bitter orange) rootstock. One orchard contained 14-year-old trees of the cv. Tarocco Scirè (a blood orange) grown in a traditional system with 494 trees/ha. The second orchard contained 12-year-old trees of the cv. Newhall (a seedless navel orange) grown in an intensive system with 1000 trees/ha. Ne…

Energy Transduction in Anaerobic Bacteria

2013

Anaerobic or facultatively anaerobic bacteria are able to grow in the absence of molecular oxygen by fermentation, anaerobic respiration, anoxygenic photosynthesis, and some other membrane-dependent reactions. Fermentation uses substrate-level phosphorylation for adenosine diphosphate phosphorylation, whereas the other processes rely on the formation of a H + or Na + potential over the membrane and a membrane-potential-driven ATP synthase. In growth reactions providing only a small free energy change, the latter reactions and use of a membrane potential is the preferred mechanism for energy conservation. Fermentation reactions supply products of biotechnological interest like short chain fa…

Transcriptional regulation and energetics of alternative respiratory pathways in facultatively anaerobic bacteria

1998

Abstract The facultatively anaerobic Escherichia coli is able to grow by aerobic and by anaerobic respiration. Despite the large difference in the amount of free energy that could maximally be conserved from aerobic versus anaerobic respiration, the proton potential and Δg ′ Phos are similar under both conditions. O 2 represses anaerobic respiration, and nitrate represses fumarate respiration. By this the terminal reductases of aerobic and anaerobic respiration are expressed in a way to obtain maximal H + e − ratios and ATP yields. The respiratory dehydrogenases, on the other hand, are not synthesized in a way to achieve maximal H + e − ratios. Most of the dehydrogenases of aerobic respirat…

Effect of changes in the cellular energy state on glucose transport activity in Brevibacterium flavum

2000

Abstract The effect of changes in cellular energy state on 6[14C]glucose uptake and activity of the phosphoenolpyruvate:glucose phosphotransferase system (PTS) in Brevibacterium flavum RC 115 cells was investigated. Energy generation in cells was varied by adding an inhibitor of cellular respiration (potassium cyanide) and an uncoupler of oxidative phosphorylation (pentachlorophenol) to the cell culture as well as by changing thiamine concentration in the bacterial growth medium. The results showed that glucose uptake in ‘respiring’ cells was inversely correlated with bacterial respiration activity: uptake declined with excess ATP generation and increased with lower ATP synthesis caused by …