A redox signalling globin is essential for reproduction in Caenorhabditis elegans.

Moderate levels of reactive oxygen species (ROS) are now recognized as redox signalling molecules. However, thus far, only mitochondria and NADPH oxidases have been identified as cellular sources of ROS in signalling. Here we identify a globin (GLB-12) that produces superoxide, a type of ROS, which serves as an essential signal for reproduction in C.

A simplified hydroethidine method for fast and accurate detection of superoxide production in isolated mitochondria.

Because superoxide is involved in various physiological processes, many efforts have been made to improve its accurate quantification. We optimized and validated a superoxide-specific and -sensitive detection method. The protocol is based on fluorescence detection of the superoxide-specific hydroethidine (HE) oxidation product, 2-hydroxyethidium.

Exploring real-time in vivo redox biology of developing and aging Caenorhabditis elegans.

Reactive oxygen species (ROS) are no longer considered merely toxic by-products of the oxidative metabolism. Tightly controlled concentrations of ROS and fluctuations in redox potential may be important mediators of signaling processes. Understanding the role of ROS and redox status in physiology, stress response, development, and aging requires their nondisruptive, spatiotemporal, real-time quantification in a living organism.

Globins in Caenorhabditis elegans.

Extensive in silico search of the genome of Caenorhabditis elegans revealed the presence of 33 genes coding for globins that are all transcribed. These globins are very diverse in gene and protein structure and are localized in a variety of cells, mostly neurons. The large number of C.

Alternative oxidase dependent respiration leads to an increased mitochondrial content in two long-lived mutants of the aging model Podospora anserina.

The retrograde response constitutes an important signalling pathway from mitochondria to the nucleus which induces several genes to allow compensation of mitochondrial impairments. In the filamentous ascomycete Podospora anserina, an example for such a response is the induction of a nuclear-encoded and iron-dependent alternative oxidase (AOX) occurring when cytochrome-c oxidase (COX) dependent respiration is affected. Several long-lived mutants are known which predominantly or exclusively respire via AOX.

Protein metabolism and lifespan in Caenorhabditis elegans.

Lifespan of the versatile model system Caenorhabditis elegans can be extended by a decrease of insulin/IGF-1 signaling, TOR signaling, mitochondrial function, protein synthesis and dietary intake. The exact molecular mechanisms by which these modulations confer increased life expectancy are yet to be determined but increased stress resistance and improved protein homeostasis seem to be of major importance. In this chapter, we explore the interactions among several genetic pathways and cellular functions involved in lifespan extension and their relation to protein homeostasis in C.

DamID in C. elegans reveals longevity-associated targets of DAF-16/FoxO.

Insulin/IGF-1 signaling controls metabolism, stress resistance and aging in Caenorhabditis elegans by regulating the activity of the DAF-16/FoxO transcription factor (TF). However, the function of DAF-16 and the topology of the transcriptional network that it crowns remain unclear. Using chromatin profiling by DNA adenine methyltransferase identification (DamID), we identified 907 genes that are bound by DAF-16.

Disruption of insulin signalling preserves bioenergetic competence of mitochondria in ageing Caenorhabditis elegans.

Background: The gene daf-2 encodes the single insulin/insulin growth factor-1-like receptor of Caenorhabditis elegans. The reduction-of-function allele e1370 induces several metabolic alterations and doubles lifespan.

Results: We found that the e1370 mutation alters aerobic energy production substantially.

Globin-like proteins in Caenorhabditis elegans: in vivo localization, ligand binding and structural properties.

Background: The genome of the nematode Caenorhabditis elegans contains more than 30 putative globin genes that all are transcribed. Although their translated amino acid sequences fit the globin fold, a variety of amino-acid substitutions and extensions generate a wide structural diversity among the putative globins. No information is available on the physicochemical properties and the in vivo expression.

Effects of sod gene overexpression and deletion mutation on the expression profiles of reporter genes of major detoxification pathways in Caenorhabditis elegans.

Reactive oxygen species have long been considered a major cause of aging. However, previous work showed that loss of superoxide dismutase (SOD) only weakly affects lifespan of Caenorhabditis elegans. Here, we examined the impact of sod gene deletion and overexpression on the mRNA levels of the remaining sod genes and other detoxification genes.

Intermediary metabolism.

Caenorhabditis elegans has orthologs for most of the key enzymes involved in eukaryotic intermediary metabolism, suggesting that the major metabolic pathways are probably present in this species. We discuss how metabolic patterns and activity change as the worm traverses development and ages, or responds to unfavorable external factors, such as temperature extremes or shortages in food or oxygen. Dauer diapause is marked by an enhanced resistance to oxidative stress and a shift toward microaerobic and anaplerotic metabolic pathways and hypometabolism, as indicated by the increased importance of the malate dismutation and glyoxylate pathways and the repression of citric acid cycle activity.

Against the oxidative damage theory of aging: superoxide dismutases protect against oxidative stress but have little or no effect on life span in Caenorhabditis elegans.

The superoxide radical (O(2)(-)) has long been considered a major cause of aging. O(2)(-) in cytosolic, extracellular, and mitochondrial pools is detoxified by dedicated superoxide dismutase (SOD) isoforms. We tested the impact of each SOD isoform in Caenorhabditis elegans by manipulating its five sod genes and saw no major effects on life span.

The Caenorhabditis globin gene family reveals extensive nematode-specific radiation and diversification.

Background: Globin isoforms with variant properties and functions have been found in the pseudocoel, body wall and cuticle of various nematode species and even in the eyespots of the insect-parasite Mermis nigrescens. In fact, much higher levels of complexity exist, as shown by recent whole genome analysis studies. In silico analysis of the genome of Caenorhabditis elegans revealed an unexpectedly high number of globin genes featuring a remarkable diversity in gene structure, amino acid sequence and expression profiles.

Prooxidant activity of the superoxide dismutase (SOD)-mimetic EUK-8 in proliferating and growth-arrested Escherichia coli cells.

Numerous studies have aimed to alleviate oxidative stress in a wide range of organisms by increasing superoxide dismutase (SOD) activity. However, experimental approaches have yielded contradictory evidence, and kinetics models have shown that increases in SOD activity may increase, decrease, or not change hydrogen peroxide (H2O2) production, depending on the balance of the various processes that produce and consume superoxide (O2-). In this study we tested whether administration of EUK-8, a synthetic mimetic of the SOD enzyme, can protect starving Escherichia coli cells against stasis-induced oxidative stress.

Molecular phylogeny of the Tylenchina and evolution of the female gonoduct (Nematoda: Rhabditida).

Tylenchina are a morphologically and functionally diverse group of nematode species that range from free-living bacteriovores, over transitory grazing root-hair feeders to highly specialized plant-parasites with complex host associations. We performed phylogenetic analyses of small subunit rDNA sequences from 97 species including an analysis that account for the RNA secondary structure in the models of evolution. The present study confirms the sister relationship of the bacteriovore Cephalobidae with the predominantly plant-parasitic Tylenchomorpha.

Dietary restriction by growth in axenic medium induces discrete changes in the transcriptional output of genes involved in energy metabolism in Caenorhabditis elegans.

Dietary restriction increases life span in a wide range of species, including the nematode worm Caenorhabditis elegans. The mechanism by which it does so remains largely unknown, although it is commonly thought that a reduction of reactive oxygen species (ROS) plays a pivotal role. More specifically, for C.

Dietary restriction of Caenorhabditis elegans by axenic culture reflects nutritional requirement for constituents provided by metabolically active microbes.

In Caenorhabditis elegans, several manipulations that affect nutrition slow development, reduce fecundity, and increase life span. These are viewed as dietary restriction (DR) and include culture in semidefined, nutrient-rich liquid medium that is axenic (i.e.

Selection and validation of a set of reliable reference genes for quantitative sod gene expression analysis in C. elegans.

Background: In the nematode Caenorhabditis elegans the conserved Ins/IGF-1 signaling pathway regulates many biological processes including life span, stress response, dauer diapause and metabolism. Detection of differentially expressed genes may contribute to a better understanding of the mechanism by which the Ins/IGF-1 signaling pathway regulates these processes. Appropriate normalization is an essential prerequisite for obtaining accurate and reproducible quantification of gene expression levels.

Wide diversity in structure and expression profiles among members of the Caenorhabditis elegans globin protein family.

Background: The emergence of high throughput genome sequencing facilities and powerful high performance bioinformatic tools has highlighted hitherto unexpected wide occurrence of globins in the three kingdoms of life. In silico analysis of the genome of C. elegans identified 33 putative globin genes.

A model of globin evolution.

Putative globins have been identified in 426 bacterial, 32 Archaeal and 67 eukaryote genomes. Among these sequences are the hitherto unsuspected presence of single domain sensor globins within Bacteria, Fungi, and a Euryarchaeote. Bayesian phylogenetic trees suggest that their occurrence in the latter two groups could be the result of lateral gene transfer from Bacteria.

Testing the rate-of-living/oxidative damage theory of aging in the nematode model Caenorhabditis elegans.

The integration of the rate-of-living and oxidative damage theory of aging predicts that lifespan extension is linked to low energy metabolism, low ROS production rates, low molecular damage and a slow aging rate. In the long-lived Caenorhabditis elegans Ins/IGF-1 mutant daf-2(e1370), low carbonylation levels and postponed morphological decline comply with the latter two of these predictions. However, metabolic rates in daf-2(e1370) refute the rate-of-living theory.

Public and private mechanisms of life extension in Caenorhabditis elegans.

Model organisms have been widely used to study the ageing phenomenon in order to learn about human ageing. Although the phylogenetic diversity between vertebrates and some of the most commonly used model systems could hardly be greater, several mechanisms of life extension are public (common characteristic in divergent species) and likely share a common ancestry. Dietary restriction, reduced IGF-signaling and, seemingly, reduced ROS-induced damage are the best known mechanisms for extending longevity in a variety of organisms.

An improved molecular phylogeny of the Nematoda with special emphasis on marine taxa.

Phylogenetic reconstructions of relations within the phylum Nematoda are inherently difficult but have been advanced with the introduction of large-scale molecular-based techniques. However, the most recent revisions were heavily biased towards terrestrial and parasitic species and greater representation of clades containing marine species (e.g.

Dietary restriction in the nematode Caenorhabditis elegans.

The nematode Caenorhabditis elegans has proved to be an excellent model organism for the study of development and aging. Many aging mutants have been discovered in the past two decades, and much has been discovered about the physiology of long-lived mutants. It therefore seems surprising that dietary restriction (DR) has not been extensively studied using C.

Genetic control of longevity in C. elegans.

The nematode Caenorhabditis elegans has proven to be a very useful tool for studying the genetics of longevity. Over 70 genes have been found to influence lifespan in this worm. Those related to the Ins/IGF signaling pathway are among the best studied and will be focused on in this review.