[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[SANET-MG] GM Wine Sold Unlabelled in the United States
ISIS Press Release 05/01/07
GM Wine Sold Unlabelled in the United States
Prof. Joe Cummins exposes the potential hazards of the GM wine yeast
that has been approved as safe by the US Food and Drug Administration
and advises against drinking US wines
A fully referenced version of this article is posted on ISIS members’
website. Details here
GM wine by stealth
Did you know that genetically modified (GM) wine has been marketed in
the United States for the past three years?
In 2003, the United States Food and Drug Administration (FDA) designated
the GM yeast strain Saccharomyces cerevisae ML01 ‘generally recognized
as safe’ (GRAS). The strain included a gene for malolactic enzyme from
the bacterium Oenococcus oeni and a malate permease gene from the
fission yeast Schizosaccharomyces pombe. Wine making involves alcoholic
fermentation via the metabolic pathways of yeast and the malolactic
pathway to convert malic acid to lactic acid, to reduce the acidity of
the wine. Malolactic acid fermentation is usually achieved using lactic
acid bacteria, which have a permease for malic acid. Putting the two
fermentation pathways in one organism seems a good idea.
The yeast ML01 was modified using a shuttle vector containing a
chromosome integration cassette with genes for malolactic enzyme, malate
transporter (permease), regulatory genes and a sequence directing
homologous recombination at a chromosomal locus (not specified in the
FDA report), and the antibiotic phleomycin gene was used as a selectable
marker via another plasmid. After culturing the selected antibiotic
resistant lactic-acid producing yeast, a phleomycin-sensitive lactic
acid producing strain was isolated and found to contain the integrated
malolactic-malate transporter genes. The original anti-phleomycin
plasmid did not contain a sequence allowing it to be integrated into the
yeast chromosome and the plasmid was therefore unstable and frequently
lost from the yeast cell [1]. The company distributing the GM yeast,
Springer Oenologie, Lesaffre Group of North America, stated that the
malate transporter gene and malolactic gene were both controlled by the
phosphoglycerate kinase gene (PGK1) promoter and transcription
terminator. The recombinant yeast softened the wine’s ‘mouth feel’ by
decreasing its acidity, and also reduces buttery flavours (diactyl) due
to lactic acid secondary metabolism [2].
Genetic modification of yeast and bacteria differs fundamentally from
modification of plants. The modification of bacteria and yeast is based
on homologous recombination while modification of plants is based on
illegitimate recombination. In plants the recombinant gene insertions
are not precise and disrupt genes that are not specifically targeted,
while in yeast, gene insertions disrupt genes that are targeted. For
yeast genetic engineering ‘shuttle’ vectors are used, which are
propagated in bacteria for insertion in yeast. The shuttle vector may
also replicate autonomously in the yeast nucleus and express genes
equipped with promoter and terminator genes. The expression vector comes
equipped with a sequence homologous with a yeast chromosomal gene.
Recombination between vector and chromosomal gene disrupts the target
chromosomal gene and inserts the transgene, and frequently also a
selectable marker, into the yeast target locus [3].
The yeast released for commercial wine production, ML01, was found to be
only somewhat substantially equivalent to unmodified wine yeast, as a
cytochrome p450 enzyme protein appeared to have been altered from the
parental strain based on a comprehensive analysis of the yeast cell
proteins, and a number of codon changes were observed in the inserted
malolactic gene cassette, but those changes were not considered
significant. Strain ML01 was claimed to reduce levels of amines such as
putrescine and cadaverine, preventing unpleasant side effects of wine
drinking [4].
Wine yeasts genetically unstable and DNA persists in wine
Neither the FDA document [1] nor the publications on ML01 [4] considered
important complications associated with wine yeast. Wine yeasts are
unstable and sudden losses in heterozygosity have been observed. Such
abrupt changes in the phenotype of wine yeasts are commonplace [5].
Numerous translocations have been observed uniquely in wine yeasts and
such chromosome rearrangements involving transgenes can lead to
unexpected toxicity in the final product [8]. Yeast cells in wine were
found to be hyperactive in mitotic recombination, contributing to the
observed instability of wine yeasts [7].
How much yeast nucleic acid (DNA and RNA) is carried over into wine?
Autolysis of wine yeast releases nucleic acids that persist in the wine
for at least nine years and contribute to the flavour of wine [8]. The
fate of yeast and plant DNA, as monitored by yeast chitinase gene and
the plant chlorophyll a/b binding protein gene and micro-satellite
markers showed that large DNA markers were present in must (the starting
fermentation mixture of mainly yeast and grape juice), while the 250
base pair micro-satellites were present in both must and young wine for
up to six months [9].
Culturable yeast cells were isolated from two out of five bottled wines
that had been filtered prior to bottling, and originating from different
locations in Greece. Unfiltered wines stored on oak barrels between 1998
and 2002 all contained live yeast [10]. The FDA letter designating wine
yeast ML01 to be GRAS indicated that the distributor of GM yeast
believed that final wines were free of yeast and yeast DNA, but no data
were provided to support that conclusion.
The dissemination and survival of commercial wine yeast in the vineyard
was studied over a period of three year, which indicated that the
strains were mainly recovered at fairly close proximity to the winery,
up to 200 metres. The yeast was largely disseminated by water runoff.
The commercial strains tended to appear and disappear from the vicinity
of the winery [11].
The yeasts from a winery abandoned in 1914 differed from those isolated
in a modern winery; with the genetic characteristics of the yeast in the
abandoned winery persisting for over ninety years [12]. A study of wine
jars from the tombs of ancient Egypt showed that S. cerevisiae had been
used in winemaking by at least 3150 BC [13]. Regulators should take note
of the time that GM yeast may persist.
FDA reviews reads like pr on behalf of GM wine
In the United States, approval of GM plants such as grapes is granted by
USDA/APHIS and those reviews provide fairly full information that is
made accessible to the public. FDA alone reviews and approves GM
microbes such as yeast used in food products. Their full reviews
including all required support information does not appear to be readily
accessible, and their approval reports, such as the GRAS notice on GM
wine yeast reads more like a public relations release on behalf of the
promoters of GM wine yeast [1]. The FDA review did not consider the
environmental and human health consequences of marketing and consumption
of GM wine. The view that the yeast and its autolysis products including
DNA, RNA, proteins and carbohydrates are somehow lost from the wine is
not supported by scientific evidence. The GM wine yeast does not appear
to have been tested for toxicity in animal feeding experiments, nor was
the must and finished wine.
A medical journal, The Lancet, pointed out that international faith in
the FDA is fast eroding because approvals are frequently influenced by
political pressure [14], and the approval of wine yeast certainly left
fundamental questions unanswered. It is surely premature to market GM
wine yeast, and as the wines produced using GM yeast are not labelled,
it is only prudent for consumers to avoid US wines unless there is
information available indicating that GM wine yeasts have not been used.
Van Vuuren, one of the patent holders on GM yeast, was recently quoted
as saying that [15],“several wineries were using the ML01 yeast as of a
few years ago”, but “it is not known if they or others are using it
today or exporting wines containing it.” Furthermore, “The company
marketing these GE yeast has no legal obligation to identify their
customers and has not done so.” Van Vuuren also said “he had heard that
some European wineries were buying the yeast in California and shipping
it to Europe.”
The Pew Report on GM Wine and Grapes asks [15]: “Are some US and
European wineries using this GM yeast for commercial production, or
merely for research purposes? If the yeast is being used in producing
commercial wines, and these wines are being exported to countries in
which it has not yet been approved for use, what can or should the wine
industry do about it?”
Currently there are no validated methods to detect GM wine made using GM
yeast ML01, and it would be necessary to have develop one.
The Industrial College of the Armed Forces (USA) indicated that the
“biotechnology industry is a critical element of national power” [16]. I
hope that military force won’t be used to make people drink the GM wine.
********************************************************
To unsubscribe from SANET-MG:
1- Visit http://lists.sare.org/archives/sanet-mg.html to unsubscribe or;
2- Send a message to <listserv@sare.org> from the address subscribed to the list. Type "unsubscribe sanet-mg" in the body of the message.
Visit the SANET-MG archives at: http://lists.sare.org/archives/sanet-mg.html.
Questions? Visit http://www.sare.org/about/sanetFAQ.htm.
For more information on grants and other resources available through the SARE program, please visit http://www.sare.org.