Subsections
Nutrigenomics:
Nutrigenomics is the characterization and sequencing of an
organism's genome and analysis of the relationship between gene activity and
cell function Nutritional genomics, or food genomics is the specific
application of genomics in research pertaining to agriculture, food
processing and food consumption. It studies how food, genes and lifestyle interact.
Nutrigenomics covers the entire food chain. Agriculture use food genomics to
increase vitality, disease resistance and drought and salt tolerance resulting
in increase of yield, reduced loss during storage and transport, enriched
micronutritions and microorganism producing auxiliary substances and food
ingredients.
The knowledge of biological active components has been developed during the
last ten years being the basis for the development of new functional foods,
looking forward to tailored functional foods and personalized foods.
Genomics researche is arousing hope that food will be adaptable to
individuals' genetic profiles. Genetic susceptibility to disease ranging from
intestinal cancer to food infection. Genomics researche is helping to map
these phenomena and give food advice to the personal genetic constitution.
Consumer will be choosing food on the basis of their own genetic constitution
within ten to twenty-five years. People will have a genetic passport that
allows them to use personalized nutrition, personal food with a preventive
function.[2527]
Nutrigenomics is not seen as a product category in itself, but rather as
supporting technology for the development of foods of greater nutritional
value, and of functional foods. [2528]
Jean Baptiste Lamarck developed at the end of
the 18th century a theory which modern biologists rated as nonsense.
Lamarck explained nature as being controlled by three biological laws:
- Environmental influence on organ development.
- Change in Body structure based on use and disuse of parts.
- Inheritance of acquired characteristics
Lamarck lived from 1744 to 1829. He was a French botanist and invertebrate
zoologist. He wrote that acquired characteristics could be inherited to
following generations, even not being genetically encoded. Genetic science
experienced then a recession. It was only in 1865 that George Mendel published
the "Mendel' s Laws" of autosomal inheritance, followed by Charles Darwin with
"The Origin of Species" in 1859. Francis Galton (his cousin) rediscovered
Mendel' s laws and is considered to be the father of modern genetics.
James Watson and Francis Crick discovered the DNA in 1940's. The Human
Genome Project begun in 1990.
Uses of food genomics
Through informatics driven metabolomic analysis it is possible to identify and
predict the impact of diet on the health of individuals with different
genotypes.
Metabolomics
[2543]
Mei Wang and colleagues 2005 define metabolomics as a concept of systems biology,
enabling the study of living systems from a holistic perspective based
on the profiling of a multitude of biochemical components. The authors stress
that it is useful to study natural products, focusing on the synergetic
effects of components which had not been considered in the study of single
active components. It studies the effect of complex mixtures, such as those
used in Traditional Chinese Medicine, in complex biological systems abridging
it with molecular pharmacology.
The small molecule inventory (SMI) or metabolome is a pattern of molecules that
reflects the cell's statues. It is the totality of metabolic processes
including anabolism and catabolism. It results from the expression of the
genome and proteome in response to the cellular environment. The metabolome
gives a direct picture of the cells activity and its environment.
The cumulative effects of all expressed and modified proteins represent an
information which is stored in the small molecular inventory (SMI) of the
cell. These molecules include important cellular function compounds, such
as nucleotides, vitamins, antioxidants and catecholamines. This area of
researche is called metabolomics.
When taken in its entirety it is not
always necessary to know the identity of individual components in a metabolic
profile. Systemic changes in pattern are indicative of specific states or
of changes in status. This can be measured by quantifying the redox active
components. Detecting and identifying subtle changes can be problematic with
the sensitivity required to identify such molecules. New analytical
technology addresses both problems using the central position of redox
biochemistry in the biological process[2544]
The general aim of metabolomics is to identify, measure and interpret the
complex time-related concentration, activity and flux of endogenous
metabolites in cells, tissues, and other biosamples such as blood, urine, and
saliva. Metabolites such as small molecules that are the products and
intermediates of metabolism, carbohydrates, peptides, and lipids vary in
concentration, size, structure, polarity, and functional groups. An integrated
set of technologies is needed to address the entire spectrum of
metabolomics.[2546]
Metabolomics in human blood:
Mass
spectrometry can now monitor enzymatic and hormonal regulation of thousands
of metabolites by means of metabolomic techniques. The German Institute of
Human Nutrition (DIFE) in cooperation with the Max-Planck Institute for
molecular Genetics of Plants in Golm/potsdam and Metanomics in Berlin are
adapting a plant analytic system for human tissue and plasma. A specific
metabolite pattern in diabetes patients was possible to be identified. More
detailed knowledge should allow the early identification of unfavorable
metabolic profiles in order to develop preventive strategies.[2548]
Plagemann revives the theory of Jean Baptiste Lamarck quoting that a high
diabetes risk can be passed on to several generations. This is not caused by
a genetic modification, but is due to an acquired condition. Experiments with
rats have demonstrated that diabetes leads to an increased level of insulin in
the unborn. The cells of the brain where the experience of hunger or satiety
are located are irreversibly damaged and the production of insulin excessively
secreted. Diabetes and overwight is therefore programed[2549].
Martin Pedersen, group leader of a nutrigenomics team of researchers from
Denmark and Japan of Chr Hansen, said that a project analyses the genetic code
of bacteria to improve probiotic food products within the four-year duration of
the project. [2528]
Supplementation during pregnancy
The mother's nutrition can be so important that it can alter her offspring's
susceptibility to disease by changing gene expression, say researchers who
claim to have explained for the first time how maternal nutrition can
predetermine risk of obesity or cancer.
Scientists from Duke University in the US showed they could change the coat
color of baby mice simply by feeding their mothers four common nutritional
supplements before and during pregnancy
Dr Randy Jirtle, senior investigator of the study, published in today's issue of
Molecular and Cellular Biology. "For the first time ever, we have shown precisely
how nutritional supplementation to the mother can permanently alter gene
expression in her offspring without altering the genes themselves."
In experiments, pregnant mice thatreceived vitamin B12, folic acid, choline
and betaine (from sugar beets) gave birth to babies predominantly with brown
coats. In contrast, pregnant mice that did not receive the nutritional
supplements gave birth predominantly to mice with yellow coats. The
non-supplemented mothers were not deficient in these nutrients.
A study of the cellular differences between the groups of baby mice showed
that the extra nutrients reduced the expression of a specific gene, called
Agouti, to cause the coat color change. Yet the Agouti gene itself remained
unchanged. This is called "DNA methylation", and it could potentially affect
dozens of other genes that make humans and animals susceptible to cancer,
obesity, diabetes, and even autism.
During DNA methylation a methyl group attaches to a gene at a specific point
and alters its function. The methyl group silences the gene or reduces its
expression inside a given cell, but does not actually change it. Such an effect
is referred to as "epigenetic"
These changes occur early in embryonic development, before the mother would
even be aware of the pregnancy. According to Dr. Jirtle, any environmental
condition that impacts these windows in early development can result in
developmental changes that are life-long, some of them beneficial and others
detrimental. If such epigenetic alterations occur in the developing sperm or eggs,
Humans and other animals are susceptible to epigenetic changes because of an
evolutionary trait in which "junk" remnants of viral infections, called
"transposons," inserted themselves randomly within the human and animal
genomes. If the transposons have inserted themselves in or near a functional
gene, the gene can be inadvertently methylated, too, thereby reducing its expression.
More than 40 per cent of the human genome is comprised of transposons that are
likely to be methylated, so any genes positioned near them could be at risk for
inadvertent methylation.
For example, methylation that occurs near or within a tumour suppressor gene
can silence its anti-cancer activity, said Jirtle. Also they do not know which
of the four nutrients caused methylation of the Agouti gene, revealing the
uncertainty of nutrition's epigenetic effects on cells.
Methylating a single gene can also have multiple effects. For example, as well as
changing coat color, mice that over-express the Agouti protein tend to be obese
and susceptible to diabetes because the protein also binds with a receptor in the
hypothalamus and interferes with the signal to stop eating. Methylating the
Agouti gene in mice, therefore, also reduces their susceptibility to obesity,
diabetes and cancer.
The researchers stressed the importance of understanding the molecular effects
of nutrition on cells, not just the outward manifestations of it.
Dr.Waterland says that diet, nutritional supplements and other seemingly
innocuous compounds can alter the development in utero to such an extent that
it changes the offspring's characteristics for life, and potentially that of
future generations. Nutritional epigenetics could, for example, explain the
differences between genetically identical twins, or the disparities in the
incidence of stroke between the South and the North.
That is the reason why all supplements such as vitamines, minerals probiotics
and a lot of other compounds should be analyzed carefully and nutrition should
be kept as natural as possible.
[2529]
[2532]
Professor John Mattick and colleagues performing the "FANTOM4"
study found that there is a sophisticated network of
regulatory elements that influence the expression of genes of the body. This
opens the understanding on how cells transform from undifferentiated cells to
mature cells with a specific function and explain why some cells turn
cancerous and how stem cells may be used use in regenerative medicine.
Some results of the study are:
Tiny RNAs
[2533]
Tiny RNAs are 18 nucleotides long, 100 times
smaller than an average gene and are the smallest genetic elements ever
described. According to the authors tiny RNAs are associated with promoters
that switch on genes, and have a role in gene activation, and may be used to
artificially control gene expression.
[]
Transposons are sequences of DNA that can move around to different positions
within the genome of a single cell, a process called transposition. In the
process, they can cause mutations and change the amount of DNA in the genome.
There are a variety of mobile genetic elements, and they can be grouped based on
their mechanism of transposition.
Class I mobile
genetic elements, or retrotransposons, copy themselves by first being transcribed
to RNA, then reverse transcribed back to DNA by reverse transcriptase, and then
being inserted at another position in the genome.
Class II mobile genetic elements move
directly from one position to another using a transposase to "cut and paste"
them within the genome.
Transposons were discovered by Barbara McClintock. She wrote that insertions,
deletions, and translocations in the genome could, for example, lead to a change
in the color of corn kernels. About 50% of the total genome of maize consists
of transposons. The Ac/Ds system McClintock described are class II transposons.
[2531] The maize Ac
(Activator) and Ds (Dissociation) elements comprise a classical two component
transposable element system of the hAT transposon family. Weber and colleagues
present an animation showing the normal Ac element transposition process.
http://jzhang.public.iastate.edu/transposition
Retrotransposons
[2534]
Retrotransposons are also called transposons via RNA intermediates and are a
subclass of transposons. They are genetic elements that move around the genome
and leave copies of themselves behind. Retrotransposons are only active in
cancer cells and cells that turn into eggs and sperm, The authors noted that
retrotransposons, which do not move around the genome any more, may still
regulate the expression of nearby genes.
[2535]
Tian Xu and colleagues 2005 found how to switch on and off the expression of
genes of the mouse genome to make it possible to study their functions. The
researchers mutate each gene, to observe the resulting changes, revealing thus
gene functions. Transposons, elements which can move from place to place in
the DNA are used in these studies. Transposons allow material to be inserted
or relocated.
Transposons have proved to be valuable genetic tools for many organisms, but not
for vertebrates and mammals. Xu and colleagues used the transposon piggyBac from
the cabbage looper moth in mouse and human cell lines. A red fluorescent protein
and an enzyme changing the colour of a mouse from white to black was added to
work as a marker. Expressions of the altered genes were inherited though five
generations. The PiggyBac transposon can be removed from the next generation by
breeding with a mouse bearing an enzyme which excises the transposon. The team
of Xu is scaling up piggyBac for the Mouse Functional Genome Project.
The Mouse Functional Genome Project
[2536]
The project tries to mutate the majority of mouse genes in China to understand
the functions of the mammalian genes in context and to identify the causes of
complex diseases having a genetic background in mammals The project aims to close
the gap between genotype and phenotype studying the function of isolated proteins
extended to their functional context in the cellular environment.
Μetabolomics [2537]
Metabolomics is, according to a definition by Daviss, the "systematic study of
the unique chemical fingerprints that specific cellular processes leave behind".
It is the study of their small-molecule metabolite profiles
[2538]. The metabolome represents the collection of
all metabolites in a biological organism, which are the end products of its gene expression, and can
give an instantaneous snapshot of the physiology of that cell.
[2539]
New terminology emerges with the new fieds of science: omics refers fields in
biology which have such a suffix genomics or proteomics, and omes referes to
genome and proteome[], which is the entire complement of proteins
expressed by a genome, cell, tissue or organism.
[2540]
The laboratory will be maintained by the University of Birmigham, which believes
that this new area of science will improve understanding of how pollutants can
impact individuals and their health.
[2541]
According to the Metabolomics Society metabolomics is a newly emerging field of
"omics"[] research concerned with the comprehensive characterization
of the small molecule metabolites in biological systems. The Society believes that
metabolomics can assess the metabolic status and global biochemical events
associated with a cellular or biological system, and reveal both the
physiological state of a cell or organism and of their responses to environment.
UK, USA and Australia are the most active countries researching in metabolomics.
[2542]
The European Nutrigenomics Organisation[] is a network linking
genomics, nutrition and health research.
A key objective of the network will be the development, data warehousing and
exploitation of nutrition and health-related bioinformatics for the benefit of
European nutrition researchers, and for the community as a whole.
[2545]
Bart De Moor et al., 2009 propose a kernel-based approach for clinical
decision support in which many genome-wide data sources are combined using an
As supervised classification algorithm, a weighted Least Squares Support Vector
Machine.
The authors stress the importance of fusing more than one source of
genome-wide data such as the genome, transcriptome, proteome, and epigenome
linked by a methodological integration framework. The authors used this
framework on a rectal cancer data set containing microarray and proteomics
data and a prostate cancer data set containing microarray and genomics data.
They noted the improving of the prediction of all outcomes when more than one
genome-wide data set was considered.
The authors concluded that integrating multiple genome-wide data sources
increases the predictive performance of clinical decision support models in
patient tailored therapy.
OurFood (c) 1998 - 2010 by Karl Heinz Wilm - Imprint (Impressum)