Leaf respiration is a major metabolic process that drives energy production and growth. Earlier works in this field were focused on the measurement of respiration rates in relation to carbohydrate content, photosynthesis, enzymatic activities or nitrogen content. Recently, several studies have shed light on the mechanisms describing the regulation of ...

The synthesis and degradation of polyhydroxyalkanoates (PHAs), the storage polymer of many bacteria, is linked to the operation of central carbon metabolism. To rationalize the impact of PHA accumulation on central carbon metabolism of the prototype bacterium Pseudomonas putida, we have revisited PHA production in quantitative physiology experiments in the ...

In the halophytic species Mesembryanthemum crystallinum, the induction of crassulacean acid metabolism (CAM) by salinity requires a substantial investment of resources in storage carbohydrates to provide substrate for nocturnal CO(2) uptake. Acclimation to salinity also requires the synthesis and accumulation of cyclitols as compatible solutes, maintenance of root respiration, and ...

While the reductive pentose phosphate cycle is responsible for the fixation of most of the carbon in the biosphere, it has several natural substitutes. In fact, due to the characterization of three new carbon fixation pathways in the last decade, the diversity of known metabolic solutions for autotrophic growth has ...

Biological diversity in marine OMZs (oxygen minimum zones) is dominated by a complex community of bacteria and archaea whose anaerobic metabolisms mediate key steps in global nitrogen and carbon cycles. Molecular and physiological studies now confirm that OMZs also support diverse micro-organisms capable of utilizing inorganic sulfur compounds for energy ...

Acetazolamide is the only carbonic anhydrase inhibitor with significant diuretic effects. It is readily absorbed and undergoes renal elimination by tubular secretion. Its administration is ordinarily marked by a brisk alkaline diuresis. Although carbonic anhydrase inhibitors are proximal tubular diuretics (where the bulk of sodium re-absorption occurs), their net diuretic ...

Treatment of heart failure involves management of risk factors and control of symptoms. Traditional management of heart failure involves the use of angiotensin converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, diuretics, aldosterone antagonists, and digitalis. Metabolic modulators are a newer class of drugs that benefit these patients by modulating cardiac ...

The promising dynamic nuclear polarization (DNP) for hyperpolarized (13) C-MRI/MRS of real-time metabolism in vivo is challenged by the limited number of agents with the required physical and biological properties. The physical requirement of a liquid-state T(1) of tens of seconds is mostly found for (13) C-carbons in small molecules ...

Experimental determination of fluxes by (13) C-tracers relies on detection of (13) C-patterns in metabolites or by-products. In the field of (13) C metabolic flux analysis, the most recent developments point towards recording labeling patterns by LC-MS/MS directly in intermediates in central carbon metabolism to increase temporal resolution. Surprisingly, the ...

Fruits of tomato, like those from many species, have been characterized to undergo a shift between partially photosynthetic to truly heterotrophic metabolism. Whilst there is plentiful evidence for functional photosynthesis in young tomato fruit, the rates of carbon assimilation rarely exceed those of carbon dioxide release, raising the question of ...

Abstract The emergence of the citric acid cycle is one of the most remarkable occurrences with regard to understanding the origin and evolution of metabolic pathways. Although the chemical steps of the cycle are preserved intact throughout nature, diverse organisms make wide use of its chemistry, and in some cases ...

The direct tracking of cellular reactions in vivo has been facilitated with recent technologies that strongly enhance NMR signals in substrates of interest. This methodology can be used to assay intracellular reactions that occur within seconds to few minutes, as the NMR signal enhancement typically fades on this time scale. ...

Understanding in vivo regulation of photoautotrophic metabolism is important for identifying strategies to improve photosynthetic efficiency or re-route carbon fluxes to desirable end products. We have developed an approach to reconstruct comprehensive flux maps of photoautotrophic metabolism by computational analysis of dynamic isotope labeling measurements and have applied it to ...

2-Oxoglutarate is located at the junction between central carbon and nitrogen metabolism, serving as an intermediate for both. In nitrogen metabolism, 2-oxoglutarate acts as both a carbon skeletal carrier and an effector molecule. There have been only sporadic reports of its internal concentrations. Here we describe a sensitive and accurate ...

ABSTRACT: BACKGROUND: Rhodobacter sphaeroides is one of the best studied purple non-sulfur photosynthetic bacteria and serves as an excellent model for the study of photosynthesis and the metabolic capabilities of this and related facultative organisms. The ability of R. sphaeroides to produce hydrogen (H2), polyhydroxybutyrate (PHB) or other hydrocarbons, as ...

The toxicity of carbon dioxide has been established for close to a century. A number of animal experiments have explored both acute and long-term toxicity with respect to the lungs, the cardiovascular system and the bladder, showing inflammatory and possible carcinogenic effects. Carbon dioxide also induces multiple fetal malformations and ...

ABSTRACT: BACKGROUND: Growth substrates, aerobic/anaerobic conditions, specific growth rate (mu) etc. strongly influence Escherichia coli cell physiology in terms of cell size, biomass composition, gene and protein expression. To understand the regulation behind these different phenotype properties, it is useful to know carbon flux patterns in the metabolic network which ...

Central carbon metabolism of living Saccharomyces cerevisiae is visualized by DNP-NMR. Experiments are conducted as real time assays that detect metabolic bottlenecks, pathway use, reversibility of reactions and reaction mechanisms in vivo with subsecond time resolution.

Metabolic disease is a complex disorder defined by various factors that increase the risk of cardiovascular disease and type 2 diabetes mellitus. In recent years, the incidence of chronic metabolic disease has dramatically increased throughout the world. These chronic metabolic diseases are associated with elevated inflammatory activities. In addition, endoplasmic ...

ABSTRACT: BACKGROUND: Ralstonia eutropha H16, found in both soil and water, is a Gram-negative lithoautotrophic bacterium that can utillize CO2 and H2 as its sources of carbon and energy in the absence of organic substrates. R. eutropha H16 can reach high cell densities either under lithoautotrophic or heterotrophic conditions, which ...

The completion of the genome project for Naegleria gruberi provides a unique insight into the metabolic capacities of an organism, for which there is an almost complete lack of experimental data. The metabolism of Naegleria seems to be extremely versatile, as can be expected for a free-living amoeboflagellate, but although ...

To identify the underlying molecular basis of carbon partitioning between starch and oil, we have conducted 454 pyrosequencing, followed by custom microarrays to profile gene expression throughout endosperm development of two closely related oat cultivars that differ in oil content at the expense of starch as determined by several approaches ...

Recent advances in liquid chromatography and mass spectrometry have enabled the highly parallel, quantitative measurement of metabolites within a cell and the ability to trace their biochemical fates. In Mycobacterium tuberculosis (Mtb), these advances have highlighted major gaps in our understanding of central carbon metabolism (CCM) that have prompted fresh ...

Ophthalmologic manifestations occur in various inborn errors of metabolism (IEM), including small molecule disorders and organelle disorders. In a minority of diseases the occurrence of eye abnormalities could be attributed to direct toxic mechanisms of abnormal metabolic products or accumulation of normal metabolites by errors of synthetic pathways or by ...

Metabolic profiling employs a combination of sophisticated analytical tools to obtain global "untargeted" metabolic profiles from tissues, cells or biofluids. The resulting complex multivariate data are then modeled statistically to reveal differences between classes (e.g. dosed vs. control) and identify discriminatory metabolites. Metabolic profiling has a wide range of applications, ...

Aim: We aimed to develop a new approach to risk stratification using metabolic syndrome as well as traditional non-metabolic risk factors, and to examine its validity in carotid atherosclerosis.Methods: A total of 1,189 men and women aged 21-93 years old were stratified according to the absence or presence of metabolic ...

Previous studies have linked levels of porcine endogenous retroviruses (PERV) with poor health and disease in pigs. To determine the levels of expression of PERVs and their potential association with disease expression, real-time reverse transcriptase (RT) PCR assays were used to assess PERV-ABC, PERV-C and PERV-A/C levels in three commercial ...

Starch is a primary product of photosynthesis in the chloroplasts of many higher plants. It plays an important role in the day-to-day carbohydrate metabolism of the leaf, and its biosynthesis and degradation represent major fluxes in plant metabolism. Starch serves as a transient reserve of carbohydrate which is used to ...

Eukaryotic methylotrophs, which are able to obtain all the carbon and energy needed for growth from methanol, are restricted to a limited number of yeast species. When these yeasts are grown on methanol as the sole carbon and energy source, the enzymes involved in methanol metabolism are strongly induced, and ...

Photosynthesis is the biological process that converts solar energy to biomass, bio-products, and biofuel. It is the only major natural solar energy storage mechanism on Earth. To satisfy the increased demand for sustainable energy sources and identify the mechanism of photosynthetic carbon assimilation, which is one of the bottlenecks in ...

Here we present a metabolic network representing the central carbon metabolism as well as the synthesis of polyhydroxyalcanohates and the polyphosphate accumulation mechanisms of the bacterium Candidatus Accumulibacter phosphatis, which was previously identified from metagenomic studies in enhanced biological phosphorous removal sludges. The reconstructed metabolic network, together with flux balance ...

Mutations in ABHD12 cause the neurodegenerative disease PHARC: an inborn error of endocannabinoid metabolism Fiskerstrand et al. (2010) American Journal of Human Genetics 87(3): 410-417.

The fixation of inorganic carbon into organic material (autotrophy) is a prerequisite for life and sets the starting point of biological evolution. In the extant biosphere the reductive pentose phosphate (Calvin-Benson) cycle is the predominant mechanism by which many prokaryotes and all plants fix CO(2) into biomass. However, the fact ...

Profound abnormalities in myocardial energy metabolism occur in heart failure and correlate with clinical symptoms and survival. Available comprehensive human metabolic data come from small studies, enrolling patients across heart failure causes, at different disease stages, and using different methodologies, and is often contradictory. Remaining fundamental gaps in knowledge include ...

Levosimendan is a calcium sensitizer developed for the treatment of heart failure. It increases contractile force by enhancing the sensitivity of myofilaments to calcium. Besides this sensitizing effect, the drug has also been reported to show some inhibitory action on phosphodiesterase 3 (PDE3). The inotropic effects of levosimendan have been ...

With the increasing availability of pigs genetically engineered to protect their tissues from the human immune response, research into xenotransplantation is progressing steadily. One potential route to the clinic would be the use of a pig heart as a bridge to allotransplantation. This would only be ethical if the outcome ...

All cardiac steroids have a similar structure, bind to and inhibit the ubiquitous transmembrane protein Na(+), K(+)-ATPase and increase the force of contraction of heart muscle. However, there are diverse biological responses to different cardiac steroids both at the cellular and at the molecular level. Moreover, we have recently shown ...

Current imaging methods have focused on evaluation of myocardial anatomy and function. However, since myocardial metabolism and function are interrelated, metabolic myocardial imaging techniques, such as positron emission tomography, single photon emission tomography, and magnetic resonance spectroscopy present novel opportunities for probing myocardial pathology and developing new therapeutic approaches. Potential ...

A hallmark of cardiac metabolism before birth is the predominance of carbohydrate use for energy provision. After birth, energy substrate metabolism rapidly switches to the oxidation of fatty acids. This switch accompanies the expression of "adult" isoforms of metabolic enzymes and other proteins. However, in a variety of pathophysiologic conditions, ...

BACKGROUND: The metabolism of pyrimidine deoxynucleosides and nucleoside reverse transcriptase inhibitors has been studied in growing cells. However, many of these drugs are associated with mitochondrial toxicities observed in non-replicating tissues, such as in the heart, where their metabolism has not been investigated. METHODS: The aims of this study were ...

AIM:To investigate the protection and the anti-oxidative mechanism afforded by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in guinea pig hearts. METHODS:Adult male guinea pigs were exposed to CIHH by mimicking a 5000 m high altitude (p(B)=404 mmHg, p(O2)=84 mmHg) in a hypobaric chamber for 6 h/day for ...

INTRODUCTION: For studying the torsades de pointes (TdP) liability of a compound, most high and medium throughput methods use surrogate markers such as HERG inhibition and QT prolongation. In this study, we have tested whether isolated hearts may be modified to allow TdP to be the direct readout. METHOD: Isolated ...

Myocytes of the failing heart undergo impressive metabolic remodelling. The time line for changes in the pathways for ATP synthesis in compensated hypertrophy is: flux through the creatine kinase (CK) reaction falls as both creatine concentration ([Cr]) and CK activity fall; increases in [ADP] and [AMP] lead to increases in ...

The advent of myocardial metabolic imaging more than 30 years ago ushered in a paradigm shift in the clinical management of patients with ischemic and nonischemic heart disease. A classic example is the so-called metabolic memory of altered glucose and fatty acid metabolism in regions of myocardial ischemia and reperfusion. ...

Turkey experimental lines E (selected 44 yr for increased total egg production) and F (selected 38 yr for increased 16-wk BW) were mated reciprocally with the randombred control lines from which they were derived (RBC1 and RBC2, respectively), and the pureline and reciprocal cross poults were compared for their BW, ...

The aim of this study was to determine the mechanism of transport of (14)C-thiamine in the hearts of healthy (nonalcoholic) and chronically alcoholic guinea pigs. We used the single-pass, paired-tracer dilution method on isolated and retrogradely perfused guinea pig hearts. The maximal cellular uptake (U(max)) and total cellular uptake (U(tot)) ...

OBJECTIVE: Heart rate recovery (HRR) is a marker for survival. Little is known about the association between HRR and metabolic risks in healthy children or adolescents. RESEARCH DESIGN AND METHODS: We examined 993 healthy children and adolescents aged 12-19 years with reliable measures of cardiovascular fitness from the National Health ...

OBJECTIVE: To determine the enzymatic and hormonal responses, heat shock protein 70 (Hsp70) production, and Hsp70 mRNA expression in heart and kidney tissues of transport-stressed pigs. ANIMALS: 24 pigs (mean weight, 20 +/- 1 kg). PROCEDURES: Pigs were randomly placed into groups of 12 each. One group was transported for ...

We have used an oligonucleotide microarray to identify genes that are affected by congestive heart failure and those influenced by treatment with DITPA and DITPA in combination with captopril using a rat postinfarction model. The most striking result when comparing heart failure to sham operation was that all of the ...

Gymnosomatous pteropods are highly specialized planktonic predators that feed exclusively on their thecosomatous relatives. Feeding behavior and the morphology of gymnosome feeding structures are diverse and have evolved in concert with the size, shape, and consistency of the thecosome shell. Here, we show that the metabolic capacity and locomotory behaviors ...