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Since the last decade, it is well established that free radicals play a critical role in normal cell function, in cell signaling, in host defense phenomenon and in various important diseases. Even if their role is well understood in some events, the evidence for radical formation is less certain in

Monitoring structural transitions in proteins is of broad general interest because they are involved in many processes, such as enzymatic activity regulation, molecular recognition and assembly, and they are at the origin of multifunctional properties. Such structural transitions are peculiarly impo

Alzheimer's disease (AD) is the leading cause of dementia in the elderly over 65 years old and now affects over 25 million people worldwide. Amyloid plaques are one of the main lesions in AD victims’ brain. A peptide called amyloid ? (A?) is their main component. The process of A? aggregation leadin

Overhauser enhanced MRI : a new MRI technique During the last three decades MRI revealed to be one of the most powerful imaging and NON-INVASIVE techniques to investigate biological processes, physiological events, and anatomy in the human being. With this tool, tremendous progresses have been repo

This project aims in molecular electronics development in order to achieve new electronic components from a single molecule or a small number of molecules. The molecules nanometric size would allow to deeply increase the present electronic devices miniaturization or the sensors performances. This

Stereoselective reactions catalyzed by heterogeneous systems constitute a smart approach for the synthesis of optically enriched compounds, achieving major goals such as selectivity, catalyst‘s recycling and green processes. In that context, one of the main advantages of metallic nanoparticles (NPs)

Chinese rural areas have undergone a series of ruptures since the Chinese Communist Party came into power in 1949. Land reform first redistributed land and other goods to rural households. A collectivization process then quickly began in 1953 leading to the creation of People’s Communes in 1958. Two

An important issue for the modelling of climate and global warming is the accurate estimation of geophysical parameters such as sea surface temperature (SST), sea surface salinity (SSS), mass transport, wave elevations and slopes and winds over the ocean surface. The retrieval of these parameters is

Boolean logical frameworks are ubiquitous in Computer Science. For computers, information is binary; the circuits (microprocessors, digital signal processors known as DSP, ...) that process it are entirely based on boolean logic; the algorithms and programs that transmit it, emph{encrypt} it, correc

The general principles underlying the processing of high strength, and ductile, metallic materials have been quite well understood since the beginning of the development of dislocation theory. If ductility requires a significant mobility of dislocations, strengthening is related to the building of o

RUPXCUBE project aims at developing innovative link between experimental and computational mechanics dedicated to the identification of three-dimensional crack growth laws. The dramatic human and environmental risks resulting from possible failure due, for instance, to rupture in aeronautic or nucle

Our project aims at developping mathematically rigorous approaches to neuroscience considering single neurons as well as interconnected neuronal populations. Our target is to conduct the mathematical analysis of existing models where there is still much work to be done and to enrich the modelling by

This project is targeted at elucidating the role of the fine control of the degree of methylesterification (DM) of the pectins of plant cell wall, and its impact on the regulation of the elongation capacity of a given organ. Pectins, which are rich in galacturonic acid, play a major role in regulati

In the flowering plants, it is well established that multimeric complex formed by MADS-box transcription factors (TFs) is responsible for the specification of petal organ identity. However, how organ identity is translated into specific growth patterns to generate organs with characteristic shapes a

Life in an oxygen-rich atmosphere has to deal with the danger of oxidative stress. Plants are especially exposed to oxidative stress caused by photosynthetic processes. Reactive oxygen species (ROS) are produced during normal cell metabolism but their production is drastically enhanced when plants a

Spray cooling is used in an increasing numbers of industrial applications. In the steel industry, during heat treatment of alloys, very high quenching rates are required to obtain strong and hard bonding in the metallurgical microstructure. The main purpose of this project is to deliver new models o

The main goal of this project is the understanding of ozone formation and decomposition with a particular insight into their isotope dependence. The formation of ozone proceeds mainly through the O2+O -> O3* chemical recombination reaction. The ozone metastable sates, O3*, can be stabilized into bo

Changes in the epigenomic state and nuclear organization of eukaryotic cells are important driving forces for proper regulation of gene expression in response to developmental and environmental signals. To gain further insight into how these - usually heritable, yet reversible - modifications influe

This project aims at providing the study of the Jacobians of small genus curves over finite fields with a rich algorithmic toolbox, in order to promote the use of these curves for cryptography. In particular, the improvements sought will be organized around efficient arithmetic and efficient point c

The goal of this project is to develop a thorough understanding of the plasma kinetics and plasma-surface interactions in inductive discharges based on CMOS compatible chemistries (i.e. on gas chemistries deployed in the CMOS industry, as Cl2-HBr-O2 containing chemistries), that will form the fundam

The aim of this project is to investigate pressure-induced amorphisation (PIA) in negative thermal expansion materials (NTE). Negative thermal expansion materials are of great interest from both a fundamental and technological point of view. Negative thermal expansion has been linked to thermally ex

The atmospheric physicists community suffers a lack of fast, reliable, space resolved measurements for a wide set of molecules playing a crucial role in atmospheric chemistry despite their very low concentrations. Many oxidants act on the atmosphere composition, giving rise to a local chemistry and

The prion protein gene family is composed of three members ; the PrP protein, which has a strong implication in prion diseases, the Doppel protein which is involved in the mouse sperm maturation and the recently identified Shadoo protein whose biological function is yet mostly unknown, as it is also

The direct metal laser deposition (DMLD) is a recent process with a real industrial potential that allows manufacturing small series or prototypes of complex shapes from the interaction between a projected powder stream and a laser. Limitations of the process come from : (1) the manufacturing time,

The current major challenge for climate science is to provide policymakers with better constrained scenarios of the Earth climatic evolution over the 21st century and beyond. This requires improving our understanding of both the climate forcings in the future and the climate sensitivity. This projec

Expanding from single component nanoparticles, research in nanomaterials now focuses on multi-component NPs with discrete domains of different materials arranged in a controlled manner. This evolution is driven by the obvious advantages of multifunctionality, the possibility to create novel function

The X-linked gene Nap1l2/NAP1L2 encodes a protein that shows similarities to the nucleosomal assembly (NAP) and SET proteins. The gene is specifically expressed in nestin positive neural stem cells and neurons, with targeted deletion of the murine gene leading to embryonic lethality associated with

Embryogenesis in chordates leads to the generation of a tadpole-like organisation, which is characterised by a central notochord and a dorsal hollow neural tube. The tadpole-like body plan is the defining feature of this group of animals which consists of the marine invertebrates, including cephaloc

The first objective of this proposal is to characterize a new family of GST related to aryl-etherases (GTEs). From literature data and previous expression data performed in the UMR1136 unit, it appears that GTE family is particularly extended in ligninolytic fungi, suggesting a function of these enz

Magneto-electric media are photonic materials in which electrical polarization is not only induced by an applied electric field, but also by an external magnetic field. They are part of a much larger class of so-called bi-anisotropic media described by a more complex constitutive equation , relating

In eukaryotic cells DNA is packaged into chromatin. Cells use remodeling chromatin factors to overcome the general repression associated with the nucleosomal organization. Energy-dependent nucleosome remodeling factors disrupt histone-DNA interactions at the expense of ATP hydrolysis. Chromatin remo

The present project is a collaboration between the group of Dr. Nathalie Picqué at Laboratoire de Photophysique Moléculaire LPPM from CNRS (Orsay, France) and the Division of Pr. Theodor W. Hänsch at the Max Planck Institute für QuantenOptik MPQ (Garching, Germany). The project will be carried out i

The surfaces of uplifted minerals during dust events are suggested to be photochemically active under atmospherically relevant conditions. Such photocatalytical properties may introduce so far unconsidered new chemical pathways that impact on the composition of the atmosphere. This project includes

In this project we study the following classes of selfsimilar processes: 1. Matrix squared Bessel processes, called Wishart processes 2. stable processes on spaces of dimension d and Ornstein--Uhlenbeck stable processes 3. study of fine properties of self-similar Markov processes The scienti

Most of the 250 millions of male piglets reared yearly in the EU are castrated by surgical means without pain prevention. Castration is performed primarily to improve meat quality and secondly to facilitate management. Indeed, pigs for meat production are usually slaughtered when testes are well dev

In this project, a library of novel classes of multichromophoric systems derived from the use of water soluble borodipyrromethene dyes (Bodipys') as the fluorophore will be designed and synthesized. New methodologies and synthetic protocols will be establish to prepare families of dyes some of which

Huntingtin (htt) is a large protein of 350 kDa whose function is not well defined. A major interest in this protein comes from the discovery that htt, when mutated, causes Huntington's disease (HD) a devastating neurodegenerative disorder that affects 1 in 10000 individuals of european origin. The n

Several fundamental problems stemming from robotics, vision and quantum physics can efficiently be modeled in the framework of Geometric Control. The study and analysis of these problems can then be ranked as research questions of Sub-Riemannian geometry (SRG for short). The purpose of this project

In the past decades, solution-state Nuclear Magnetic Resonance (NMR) spectroscopy in liquids has evolved to become a powerful method for the study of internal mobility in proteins and other biomolecules, primarily through the measurement of spin relaxation rates and residual dipolar couplings. These

IN-ART is a fundamental research project having the aim of designing, fabrication and characterising a prototype artificial flying micro-insect on the centimetre scale. Here, flight requires wing beating and thus requires actuation which we intend to achieve using polymer-based microactuators. The I

In this innovative and fundamental investigation, we will try to determine the scope that carbon-rich organometallics present for developing new functional materials in the field of optics. In this connection, redox-active electron-rich acetylides of the group 8 metals (iron notably) have been rece

In this proposal, two groups from a single partner (Institut Parisien de Chimie Moléculaire) at the University Pierre and Marie Curie-Paris 6 are joined together with strong complementary expertise. The proposed work lies in the field of asymmetric organometallic catalysis, from coordination chemist

The principal motivation of the present research program is development of a new approach for fabrication and assembly of nano-hybrid systems consisting of a semiconducting metal oxide core with enhanced and controlled multi-photon absorption and functional organic molecules attached to the core sur

The objective of the GamHadron project is to design, optimize, develop and characterize an imaging system for on-line monitoring of the dose deposited during a hadrontherapy treatment. Three-dimensional imaging of the dose deposited in the patient is particularly important in hadrontherapy, because

The aim of this Supercritical Microfluidics project (µFSC) is to develop scientific and technical knowledge, allowing to design, realize, and use microfluidic devices, that concern for the first time supercritical fluids in wide ranges of temperature and pressure. Maximum operating conditions are up

Theory of irreducible symplectic varieties (ISV) has two aspects, geometric and arithmetic. The geometric aspect includes the description of families of ISVs which possess particular geometric properties or are obtained by specific constructions. From the point of view of moduli theory, different ge

The mechanical properties of polycrystalline metals with nanometric or ultrafine grains differ dramatically from their bulk counterparts due to grain boundary strengthening effects. They have, therefore, attracted a great deal of interest in the recent years. However, the knowledge of the underlying

Nitrogen is the mineral nutrient required in the highest amounts by plants and is most frequently limiting for growth and yield, leading to massive use of N fertilizer in agriculture. In higher plants, the molecular basis of root NO3- uptake has been the matter of intensive studies during the last d

Taste is in charge of evaluating the nutritious content of food and preventing the ingestion of toxic substances. Sweet taste helps us choose high energy food whereas bitter taste protects us agains ingesting toxic substances. Taste sense organs are located in the pharyngeal cavity (tongue in mice a

In the past decades spintronics has been the subject of intense investigations because of both its large fundamental interest (mechanism of spin-transport) and its high potential for applications (read heads in hard drives, MRAM, etc.). Nowadays, the parallel developments of theoretical and experime

The scientific community can now study and simulate physical, chemical and biological phenomena with mathematical models of increasing level of complexity. However many models involving system of partial differential equations (PDEs), with a large number of unknowns as well as a large spectrum of te

Trypanosoma brucei is a flagellated protozoan parasite that is used as a model organism to study biological phenomena such as gene expression, protein trafficking and cytoskeleton biogenesis. In T. brucei and related parasites endo- and exocytosis occurs exclusively through a specialized, sequestere

Dendritic cells (DC) play a key role in the regulation of immune responses generated by vaccination which is an effective and sustainable way to control infectious diseases, both in human and in animals of our environment (specific diseases and zoonoses). The design of new vaccine strategies implies

Pathogens are a threat for crops and natural plant populations. A major challenge in plant breeding is to identify the genetic and molecular bases for natural resistance variation in plant species. The identification of genes underlying natural resistance variation might have enormous implications f

Microtubules are dynamic structures of the eukaryotic cytoskeleton. They are involved in functions as different as the intracellular traffic or the formation of the mitotic spindle. They alternate between growth and shrinking phases in a process termed dynamic instability. The ''-tubulin heterodimer

The development of new catalytic systems able to perform C-C coupling by C-H bond activation without using organometallic intermediates represents the objective of this project. This method will make possible the selective functionalization of sp2 carbon atoms of aromatic substrates, heterocycles, a

Stress response is one of the most studied themes in the biological sciences and has, in recent years, gained considerable attention for its importance to ecology and evolutionary biology. Stress occurs when an organism's functions are disrupted by an environmental change. This is accompanied by eit

We wish to develop mathematical tools in order to understand the thermodynamical properties of quantum systems out of equilibrium. Indeed, despite the fact that the mathematical structure of equilibrium thermodynamics is well-understood, the situation is far from satisfactory out of the equilibrium

The aim of the project is to develop promising emerging connections between disordered systems, non-equilibrium phase transitions and statistical turbulence. A common denominator in these traditionally separated domains is the crucial role played by singularities, such as shocks and avalanches, in t

Within the GeoBridge project, we aim to develop several advanced and original experimental techniques that allow for: 1. assessment of the transition from diffuse to localised deformation or fault initiation in rock specimens under realistic 3D loading (three non zero principal stresses), using an i

INTRODUCTION: Communications systems require complex modulation formats such as 256 QAM modulation format, and faster symbol rate. Today, in order to fulfil these characteristics, equipment manufacturers currently require monolithic VCOs whose main features are: - A centre frequency between 2 GHz an

This project exploits the capacities of a high cooling power refrigerator for implementing a large dimensions von Karman flow (diameter 80 cm), working as well with liquid or gaseous helium, as with superfluid. Von Karman flow is producted between two parallel contrarotating disks. It is now well do

Nanostructured surfaces are characterized by elementary structures whose size varies between a few to several hundreds of nanometers. Important researches have been recently done on small scale surface structuration owing to its important possible applications to micro-thermo-fluidics. According to

MHC class I molecules present peptides produced by intracellular degradation of antigenic proteins to CD8+ T lymphocytes, which can mount cytotoxic responses against cells displaying non-self peptides derived from pathogens or tumour-associated proteins. While most cell types display exclusively pep

Cytokinesis is the complex process by which two daughter cells physically separate at the end of cell division. Understanding this process is a very important goal, not only for its basic biological significance, but also for its practical implications. Indeed, cytokinesis failure can lead to polypl

Following the pioneering studies of H. Kosaka, many studies focused these last years on the engineering of ultra-refraction effects. Ultra-refraction effects are classically divided into two main categories: superprism effect and self-collimation effects. The superprism effect allows one to strongly

The goal of this proposal is to demonstrate active quantum feedback procedures to generate and/or protect specific quantum states of a trapped field. Instead of initially preparing a given state and passively observing its evolution under the effect of the coupling to the environment, we will perfor

Transmissible Spongiform Encephalopathies (TSEs) or prion diseases are fatal either infectious, genetic or sporadic neurodegenerative disorders of humans and animals, caused by a conformational conversion of a host-encoded GPI-anchored protein, PrPC (cellular prion protein). Conversion of this norma

Calcification of the extracellular matrix (ECM) can be physiological or pathological. Physiological calcification occurs in bone during skeletogenesis whereas pathological calcification can occur in arteries, cartilage and other soft tissues. During arterial calcification cells lose their expression

This research project is focused on the fundamental study of biological apatites and their growth on biological interfaces. The main objective is to try to answer the following question "why and how mineralization occurs at the HAp/biological media interface'" The consortium, with complementary expe

Exchanging light pulses to perform accurate space-time positioning is a paradigmatic issue of physics. From a fundamental point of view it is the technique used to synchronize clocks situated at remote locations that is at the root of Einstein's concept of space and time. From a more practical point

Because of the current and predicted environmental problems, the agronomic conditions for crop production are going to change in a near future. In particular, the yields of future crops must satisfy human needs, but with reduced supplies of fertilizers. Thus, the yields will have to be maintained al

The aim of this project is the combination of state of the art analytical and numerical methods to study nonlinear dispersive partial differential equations arising in different fields of mathematics and physics with highly oscillatory solutions. The analytical approach will use Riemann-Hilbert tech

The study of moduli spaces of geometric structures on surfaces is an important theme in the development of mathematics over the last decades (Teichmüller theory, etc). Some important and exciting developments have happened more recently (including in France). The deal with new approaches of some a

The project presented here is a truly collaborative effort between two laboratories with complementary expertise. The basic issue addressed is the implication of the nicotinic receptor (nAChR) in nicotine dependence, leading to lung cancers. Lung cancers are among the most common human malignancies.

Genomic reprogramming reverts fully differentiated cells to toti- or pluripotent state to start a new developmental program. In the early mouse embryo, fully differentiated gametes are reprogrammed after fertilization to totipotent- and subsequently to the pluripotent state. Epigenetic reprogramming

Non viral gene delivery systems have benefited from considerable development over the last two decades and constitute a very promising alternative to viral vectors for gene therapy. The synthetic vectors have many advantages in terms of biosecurity, ability to carry a gene of unlimited size, low cos

The UBIQUEST project proposes to combine the network management and data management in a single framework. Our objective is to design a query language for ad hoc networks and to develop the distributed query evaluation techniques that will efficiently compute queries expressed in this language. The

Heavy-ion accelerator provides the possibility to explore the interaction of highly charged ions (HCI) with matter in a unique regime that is governed by virtual photons, advancing our knowledge about the physics of strong fields. At high velocity it has been demonstrated that the attosecond super-i

SNARE induced membrane fusion is involved at every level in intra-cellular traffic. However, molecular details of this fusion machinery such as kinetics and molecular organization remain largely unknown. We propose, thanks to a tight collaboration between our complementary teams, to use a novel appr

Processing the data at large dimension scale is becoming one of the great challenges of the 21st century. The most notable recent advances in statistical data analysis and numerical simulation are based on the idea that in several situations, even for very complex phenomena, only a few governing com

A major objective of current research in zoology and evolutionary sciences is to understand the molecular basis of natural diversity. A powerful approach to identifying the developmental genetic basis of morphological adaptations is the comparison of a model organism in which the genetic control of

The number of sequenced genomes has greatly increased in the last years, with each additional genome sequenced clearly establishing the importance of transposable elements (TEs) in most genomes. These middle repeated DNA sequences are able to move around genomes, i.e. to transpose, and are thus impo

The emergence of new animal models that mimic human disorders (neurodegeneratives diseases, tumour growth, neuropsychiatric disorders) enables new fundamental and therapeutical approaches of these diseases. The increasing number of studies on animal models implies the development of new imaging tool

Severe sepsis syndrome/septic shock or Acute Respiratory Distress Syndrome are clinically acute inflammatory syndromes associated with a mortality rate of 20-60% and are the leading cause of death in adult intensive care units. They are one of the many pathologies for which the underlying mechanisms

Mitochondria are the powerhouse of eukaryotic cells. They have there own genome which codes for 13 proteins, all involved in the process of energy synthesis, and accordingly possess also a dedicated and specific translation machinery. Transfer RNAs and aminoacyl-tRNA synthetases, key macromolecules

The increasing complexity of target compounds in organic chemistry requires, nowadays, the development of original methodologies which allows to efficient carbon-carbon bond-forming reactions between highly functionalized moieties. Within this perspective, poly-functionalized organometallic species

Most solid materials in everyday life are crystals, whose constituents (atoms, molecules') are regularly positioned in space, as, e.g., in metals or ceramics. Over the past century, scientists have reached a good understanding of the electric, thermal, and mechanical properties of a defect-free crys

Chemical synthesis has shown its ability to elaborate magnetic nano-objects with high-quality magnetic properties, either under the form of molecules, or of nanoparticles (NPs) with well-controlled properties. These objects already play a major role in several actual technology fields (MRI,magnetic

This project focuses on the study of magnetic anisotropy in Single Molecule Magnets (SMMs). A crucial stake for the scientific community of this domain consists in controlling and tunning the anisotropy for both technological devices (information storage and quantum information) and fundamental purp

Acetylcholinesterase (AChE) is a key enzyme for the transmission of the nerve impulse. This enzyme has a hydrophobic gorge of approximately 20 Å separating an acylation catalytic site, and a peripheral site located at the entry of the gorge. Organophosphorous Nerve agents (pest control or warfare ag

This project combines synthetic inorganic chemistry, Fluorescence Resonance Energy Transfer (FRET), time-resolved pump-probe and steady-sate absorption/emission spectroscopies with accurate methods of quantum chemistry and excited states dynamics. Our aim is to discover new ruthenium based metallo-

CONTEXT: The recent discovery of an intermediate phase between the well-known flexible and rigid phases in network glasses has opened a new field of investigation in glass science with potential interesting applications. Indeed, this phase displays a certain number of remarkable properties such as t

Energy saving as well as efficient energy management is seen as one of the key issues to postpone the warming of the global climate system. Today 40% of all energy consumption is electrical energy, with increasing tendency in future. Therefore power electronics plays an important and growing role in

The control of acidity is a well-known prerequisite of any chemistry experiment performed in an aqueous solvent. In such liquids, acidity is given by a unique quantity, the pH, which is defined from the activity of the proton. It is readily and precisely evaluated through simple devices or electroch

Our project finds its basics in the MAD-BLOCK project previously submitted as an "ANR blanche" proposal in 2008. Here, the main comments concerning the strong fundamental versus applied weight of the proposed sciences have been re-balanced by introducing an additional panel dedicated to spintronic/s

The most conspicuous manifestations of the ongoing climate warming are found in the Arctic. Changes in this region outpace the most pessimistic climate model predictions. Summer sea ice extent has shrunk very substantially (ice cover 40% smaller in 2007 than the 1980-2000 median). Multiyear ice decl

The aim of OPALE is to establish the present-day oxidative capacity of the atmosphere over the Antarctic plateau, which appears to be unexpectedly strong due to the presence of the snow cover, to assess its influence on coastal Antarctica, and to forecast its future change in response to the recover

We propose the detailed study and prototyping of a Super-Station for the LOFAR radiotelescope (LSS). France is inthe process of purchasing a LOFAR station to be installed in Nançay.; it thus participates to the europeanization of this radiotelescope of new generation, precursor of SKA and other inst

A decade ago, it was thought that the global star formation history of galaxies at cosmological scales was relatively well constrained by the optical and UV data. Soon after, 15 microns observations with ISOCAM, onboard the Infrared Space Observatory (ISO), and sub-millimeter SCUBA results from the

It is now well established that Mars' atmosphere evolved from an early Earth's like atmosphere 4 billions years ago to the present dry and thin atmosphere. However, we still ignore why and how most of the water, still present on Earth, disappeared from Mars' surface. Actually, we even do not know if

Atmospheric CO2 concentration has increasedby more than 30% since the pre-industrial era mainly due to industrial emissions and this increase is very likely at the root of the observed temperature rise of 0.6°C over the last century. Although we have good estimates of the CO2 fluxes on a global basi

This proposal seeks support for an integrated geochemical and modelling study of the Himalayan erosion and its interactions with climatic changes, in the present and in the past. Indeed, improving our understanding of the interactions between climate and the surface is one of the most challenging is

The presence of water (or hydrogen) in nominally-anhydrous mantle minerals, as well as its influence on the chemical and physical properties of these minerals, has been known for almost twenty years. Nevertheless, the total amount of water stored in the mantle is still very poorly constrained and th

The expression of mitochondrial genes relies heavily on protein factors encoded in the nucleus. Very little is known about these genetic processes in higher eukaryotes. Nevertheless, the PentatricoPeptide Repeats (PPR) protein family plays fundamental roles in these expression processes in terrestri

Endophagous hymenopteran parasitoids have evolved a variety of strategies to circumvent the immune defences of their insect hosts. An increased number of data on these factors is now available showing that they belong to different types: proteins from wasp venom gland or ovaries, particles of viral

Plants are exposed to a great number of pathogenes, only a small proportion cause diseases. Indeed, plants defend themselves against microorganisms by triggering a wide range of mechanisms. A better understanding of the molecular basis of defence is not only of high scientific interest, but also an

Symbioses between arbuscular mycorrhizal (AM) fungi and plants have significant effects on plant biodiversity and carbon cycling, and are therefore of considerable agricultural importance. The discovery that strigolactones, which are secreted by plant roots, are root-recognition signals for AM fungi

In eukaryotic cells, mitochondria ensure fundamental functions in energy production, redox processes, metabolic pathways and cell death. The mitochondrial genetic system provides a number of polypeptides which are essential for cell survival, as they are components of the respiratory chain or contri