The Chicken that lays golden eggs

We have all heard of the fairytale but soon they may longer be just a mystical creature. Researchers at the Roslin Institute have produced genetically modified chickens that lay eggs full of cancer fighting proteins. This research could lead to a faster and cheaper way of manufacturing drugs on a large scale.

Currently, the active ingredients of drugs are made in industrial bioreactors which are time consuming and expensive to set up. An increase in global demand for pharmaceuticals has led researchers to explore more efficient and economical alternatives to standard techniques such as the use of transgenic animals.

A transgenic animal is one that has had external genes incorporated into its genome. In this way, the gene for a protein of a drug of interest can be transferred into the genome of an animal which transmits it to successive generations. The use of chickens offers many advantages. Chickens reproduce quickly, lay lots of eggs and are cheap to look after.

Ovalbumin makes up more than half of the protein in the white of an egg. Researchers have modified the gene that makes ovalbumin so that it produces therapeutic proteins. The proteins are then easily extracted and used in the manufacture of drugs.

The manufacture of drugs created in this way is in its early stages and it will be some time before we see these drugs available on the market. There are ethical issues involving animal welfare and the genetic modification of animals that need to be debated.

Philippa Hall

40113456

Viruses: A Cure for Cancer?

Malignant tumours (tumours with invasive characteristics) or cancer has been an increasing problem in both animal and human health. Recent studies have discovered another weapon to stopping them - the chicken anaemia virus (CAV).

CAV causes both clinical and subclinical diseases in chickens, characterised by anaemia, lymphoid atrophy and immunosuppression. This virus is known to be link with the apoptosis of cells, a form of cell death. The virus contains genes that generate 3 distinct proteins: VP1, VP2 and VP3. The VP3 protein was determined to be responsible for inducing cell apoptosis in chicken mononuclear cells, leading it to be named Apoptin. The good news is that VP3 not only induces apoptosis in chicken mononuclear cells, but also in malignant tumour cells. The ‘special’ ability of the VP3 protein is that it only attacks tumour cells and non-tumour cells, making it an exceptional anti-tumour agent.

Studies have begun investigating the effect of the VP3 gene, which produces the VP3 protein on canine mammary tumour cells. The VP3 gene was introduced into tumour and non-tumour cells via expression vectors (genes constructed containing at least a promoter, transcribed and transcription region) encoded with the VP3 gene of the CAV. The results indeed confirmed VP3 gene’s ‘special’ ability. Therefore, it may be an encouraging agent in treating mammary gland tumours in dogs. Veterinary medicine is not the only area to benefit from this discovery, as it could also lead to a better treatment of human breast cancer.

Primary Source

Lee, JJ., Chen, PB., Yang, SH., Cheng, CH., Chueh, LL., Pang, VF., Hsiao, M., Lin, CT., 2007. Effect of the VP3 gene of chicken anemia virus on canine mammary tumor cells. American Journal of Veterinary Research 68, 411-422. [electronic abstract]

Secondary Sources

Noteborn, MH., 2004. Chicken anemia virus induced apoptosis: underlying molecular mechanisms. Veterinary Microbiology 98, 89-94. [electronic abstract]

Houdebine, L., 2003. Animal Transgenesis and Cloning, edition unknown. John Wiley & Sons Ltd, West Sussex, p.16.

Posted by Sarah Zhang (41426957)

Pharms of the Future

The common chicken may prove to be the next big thing in pharmaceutical production.

Scientists have succeeded in producing transgenic hens that are able to synthesise therapeutic proteins. This may lead to a quicker, easier way of producing anticancer drugs.

Bioreactors (which use bacteria to produce proteins) are currently used, but are expensive and time-consuming so alternatives have been an area of research. Therapeutic proteins are already produced in other transgenic animals (animals containing genes from another species within their genome) such as goats, rabbits and cattle. Using chickens is appealing in that only a 5 month generation time is needed, meaning breeding to produce a large transgenic flock is much quicker than in animals such as goats. Chickens are also cheaper to maintain, and there is the possibility of producing proteins that are toxic to mammalian cells.

The process involves injecting the embryos of newly-laid eggs with viruses that contain the genetic sequences coding for one of two specific proteins (Wayman, 2007). The protein is incorporated into the DNA and results in a transgenic cockerel which is crossed with normal hens to produce transgenic chicks. These chicks go on to pass the proteins into their eggs where it can be collected from the egg white and ultimately used in human drugs.

Importantly, the proteins have been restricted to the oviduct, as the proteins may be harmful to other parts of the chicken. There still needs to be testing for effectiveness in humans, but it mightn’t be too long before eggs become our new drug supplier.

By Julia Smith
41409286

References

Jones, H., (2007) Chicken eggs make human drugs. Cosmos Online. http://www.cosmosmagazine.com/node/966

Lillico, S., Sherman A., McGrew, M., Robertson, C., Smith, J., Haslam, C., Barnard P., Radcliffe, P., Mitrophanous, K., Elliot E., and Sang H., (2007) Oviduct-specific expression of two therapeutic proteins in transgenic hens. PNAS, February 6, 104:6 p 1771-1776 www.pnas.org/cgi/doi/10.1073/pnas.0610401104

Wayman, E., (2007) Barnyard Pharmaceuticals. Science Now. http://sciencenow.sciencemag.org/cgi/content/full/2007/116/4

Genetically engineering animal proteins for pharmaceutical benefit

Genetically engineering animal proteins for pharmaceutical benefit

Gene farming of animals in order to produce useful proteins and other pharmaceuticals has been tried and tested on numerous animal species, such as cattle, sheep and pigs. This “gene farming” involves altering an animals DNA or to add additional DNA from another species, which can be achieved by microinjecting a cell (such as a fertilized egg) before it divides and develops (see http://learn.genetics.utah.edu/features/pharming/).

Technology such as this has already assisted humans in developing many life-saving protein drugs such as insulin, which is used to treat diabetes. Gene technology allows human proteins that are provided only by mammals, to be manufactured, thus treating diseases and saving lives (Gillespie, 2007). Farm animals such as cattle are advantageous for this practice as they have high reproductive capacity and are easy to care for and maintain (Gillespie, 2007). The proteins produced are present in blood and milk produced by the animals, which can then be easily collected for further research and drug development.

Despite the potential life-saving advantages of gene farming animals for protein and drug development, the moral and ethical dilemma’s associated with the issue are of great concern. Gene farming for pharmaceuticals has the potential to cause significant harm to the animals involved, by infecting the animal with viruses, as well as interrupting the animal’s normal gene functionality that can result in abnormalities (Straughan, 2004).

HOG a kidney - future reality?

Approximately, 180 000 people around the globe are currently waitlisted for an organ transplant and fewer than one out of three people will survive. Could pigs be the solution to this devastating medical predicament??
Xenotransplantation, is the transplantating of living cells, tissues or organs from one animal species to another. Currently, xenotransplants is mainly focused on transplanting organs in particular from pigs to human due to physiological similarities. Genetically engineered pigs with the hyperacute rejection gene knocked out are used as organ, tissue and cell donors for a myriad of diseases and illness in humans.
To turn this possible medical breakthrough into a reality, however, a number of obstacles must be dealt with including zoonosis, further genetic engineering to prevent rejection due to the enzyme a-1,3 galactosyltransferase present on pig cells and a range of ethical and religious dilemmas.
One of the obstacles, xenozoonosis, is mainly concerned with creating a public health disaster such as epidemics or pandemics and the transmission of porcine endogenous retroviruses and swine influenza from pigs to humans. Where genetics plays a key role is in the inactivation of the enzyme a-1,3 galactosyltransferase present on pig cells which creates a sugar that the human body recognizes as foreign and leads to immune rejection. Religious dilemmas could be raised because it is against some relegions to eat pork. Animal welfare and ethics have been put foward as major issues in xenotransplantation. Is it humane and ethical to raise pigs solely for human benefits? Unless these issues are resolved xenotransplants will remain only a “possible” medical breakthrough.



by: Sonia Vaswani (41310832)
Primary references:
Cozzi, E and Ancona, E , 2003, 'Xenotransplantation, where do we stand?' Journal of nephrology , vol. 16, no. 7, pp.16-21
Access article here

Dobson, R.A., 2002, ‘Scientists produce genetically engineered, cloned pigs for xenotransplantation.’ BMJ, vol. 324, no. 673
Access article here

Secondary references:
Cox, A. and Zhong, R., 2005, ‘Current advances in xenotransplantation’ Hepatobiliary pancreatic disease Int, vol. 4, no. 4, pp. 490-494
Acces article here

They’re larger than life and will light up your life: Transgenic Fish

A transgenic organism is genetically engineered to express genes from another species by inserting the desired gene into the DNA of a fertilized egg. Many species of fish have had a transgene inserted into their genome to produce a desired phenotypic characteristic. The most common phenotype targeted is growth rate. This is achieved by incorporating a growth hormone gene into the DNA of the fish. At the other end of the spectrum, researchers at the National University of Singapore incorporated the fluorescence gene from a sea anemone into a zebra fish. The result was a fish that fluoresced. Commonly called the Glofish, it became the first marketed transgenic pet.

The production of transgenic fish for commercial trade would provide many advantages to fishing industries worldwide; however faces many ethical limitations.

Transgenic Salmon with an incorporated growth hormone gene grow to extraordinarily large sizes within the same time span as compared with their wild type counterparts. This would increase the rate of aquaculture production by lowering the age at which target sale weight is reached, thus providing positive effects for the fishery industry. Also, the novelty of owning a fluorescing fish has developed and promoted a highly profitable commercial market for the Glofish within the pet industry.

A major limitation to any genetic modification is ethical considerations. Concerns about possible food safety issues and environmental impact of transgenic fish have restricted commercialisation and global trade. California, Canada, and the European Union have prohibited the import and sale of genetically modified fish for these reasons.

Miranda Flinn (41186194)

Identifying bacterial species by making cloned DNA probes

Many bacterial species that are part of the Campylobacter group have been identified as disease – causing agents of animals and humans. One species that is of veterinary importance is Campylobacter hyointestinalis, which causes proliferative enteritis in pigs and other animals. However, many Campylobacter species appear similar, making it difficult to confidently diagnose which species is infecting a patient using visual identification methods. This delays proper treatment and causes confusion as to which species is causing disease if there are multiple species present.

Instead of using visual differences between species to determine which Campylobacter species is causing disease in a patient, probes for particular species are being developed by cloning DNA fragments from the bacteria’s chromosomes. These DNA probes will allow for rapid identification of different Campylobacter species because a DNA probe will only form a hybrid with the DNA of the species it was cloned from and not any other species, even if they are similar.

Campylobacter hyointestinalis probes were made by cloning fragments of chromosomal DNA into a plasmid vector, and allowing the fragments to be combined into the plasmid DNA as it replicated. The probes were then mixed with Campylobacter hyointestinalis and Campylobacter fetus, to see which probes would show specificity for Campylobacter hyointestinalis. When these probes were tested in samples from animal specimens, they only formed hybrids with Campylobacter hyointestinalis. This demonstrates cloned DNA probes are a quick, efficient method of identifying specific disease – causing bacteria in an animal, leading to faster diagnosis and treatment of diseases.

If you wish to read about other experiments within veterinary medicine that involve cloning DNA, follow these links:

http://cvi.asm.org/cgi/reprint/12/2/334

http://journals.cambridge.org/download.php?file=%2FPAR%2FPAR125_03%2FS0031182002002019a.pdf&code=62919565bfd61c5f0e7fa9d615b280fd

Genetically Engineered Salmon is coming to our kitchen ?

Over the past few years, genetically engineered (GE) salmon has been waiting for certification from the US Food and Drug Administration (FDA) to go to market.

GE salmon grows two to three times faster than natural salmon under the same condition due to their high level of growth hormone. Normally salmons produce growth hormone only during summer period but inserting gene which produces growth hormone and gene which stimulates the first gene into fertilized egg enabled the fish to produce growth hormone year around, resulting amazingly fast growth.

This has been in the spotlight as it may help cutting cost for fish farmers and feeding the growing population however there are several considerable issues on bringing GE salmon to market.
first issue is that GE salmon may decrease the price of salmon on market and some farmers working for salmon industry could lose their jobs.
Another issue, which always arises from genetically modified food, is human health. Studies showed that farmed salmon contains more dioxin and other cancer-causing contaminants that natural salmon.
Effect on the environment and wild fish is also concerned problem. If GE salmons escape into sea they could contaminate original species of salmon and other creature in the water.

therefore it is believed that more experience is needed before release of GE salmon to market however it is depending on the decision FDA is making,,,,.

Posted by Kyoko Sato (41142640)

Primary resource
Union of concerned Scientists. 2001. 'Genetically engineered salmon' Accessed 29 May
.

Secondary resource
Center for Food Safety. 2003. 'Genetically Engineered fish' Accessed as 30 May .

Carbon Copy Cats

Cloning is a relatively new scientific advancement. Many animals have been cloned to date, including cows, goats, sheep, mice and even dogs and cats.
There have been several successful attempts at cloning both wild and domestic felines, for example Cc (Copy cat), the first cloned ‘pet’ and Madge, Caty and Ditteaux, three African wildcats, all of which are healthy and energetic. Madge and Caty have even had 8 kittens collectively, fathered by Ditteaux.
The cats were all cloned using a nuclear transfer method, where a cell of the cloned animal is inserted into an emptied ovum (nucleus has been removed) and then the ova containing the cloned DNA is inserted into the uterus of a hormonally-receptive surrogate mother. The cells of the ‘cloned’ animal are forced into a dormant phase, Go phase, before insemination. In this dormant state the cell shuts off all gene activity and the cell loses its differentiation. Once the cell is re-activated (electric pulse) and inserted, the cell is then able to divide and re-differentiate as the embryo develops.
Cloning has a low success rate. Of the few animals that fall pregnant, many either lose the embryo during development or the cloned kitten is born with severe abnormalities and dies shortly after birth. In Cc’s case, she was the only surviving kitten out of 87 embryos created via cloning.
Cloning is an important advancement as it has the potential to further our attempts in the conservation of endangered species by cloning several individuals of a population(s), mating them and releasing the animals and clones back into their natural habitats. Provided the current threat to the species is addressed many species at risk of extinction could be saved. Cloning could also be useful in the study of diseases in both animals e.g. inherited diseases of purebreds, and humans, as dogs and cats are good models for many human diseases e.g. feline aids.

Sabrina Christoff-Tzazaroff (41211265)

· http://news.bbc.co.uk/2/hi/science/nature/4172688.stm

· http://news.bbc.co.uk/2/hi/science/nature/1820749.stm
· http://www.newscientist.com/article.ns?id=dn7785

Genetically Engineered Pigs to Save Lives

Xenotransplantation (inter-species transplantation) could solve the organ shortage problem. Pigs are suitable animals for this due their large litter sizes, their fast growth rate and because they can be reared in conditions which are pathogen free. They can be genetically modified to produce organs which the human body is less likely to reject on transplantation and although pig valves and skin has been used in human transplants, entire organs have not yet been used as immune system attack is much more aggressive when organs are transplanted between species, rather than within species.

Hyperacute rejection was avoided by genetically modifying some pigs to lack the gene alpha-1, 3-galactosyferase, which adds sugar molecules to its cells, as monkey and human immune systems aggressively reject this. Another hurdle, cell mediated rejection, where transplanted organs are rejected 1-2 weeks after transplantation due to attack by specific T lymphocytes, however immunosuppressive drugs can quieten this immune system response. Delayed xenograph reaction occurs within 3-5 days of the transplant, where platelet coagulation in the donor organ’s blood capillaries occurs due to activation of inflammatory responses. Through addition of human compliment modulating proteins, this can be suppressed. The use of pig organs in humans would gain significant health and economic benefits as the demand for organs may match the supply and money spent on caring for organ failure patients would be reduced. However, a concern is that pig organs could be carriers of unknown viruses along with ethical objections to using humanised animals as organ farms.

More On Their Rump, Less On Ours

Double muscling is a phenotype associated with a mutation in the myostatin gene so that it produces an inactive form of myostatin, unable to regulate muscle fibre deposition. Present in European beef cattle breeds such as the Piedmontese and Belgian Blue, it is characterized by an excessive increase in the size and number of muscle fibres within the animal. The meat of double muscled cattle is much leaner, with lower saturated fat content, both exciting prospects for the health conscious beef-lover.

Whilst the manipulation of the myostatin gene (through selective breeding) to produce these favourable characteristics seems attractive, double muscled animals homozygous for the mutant allele are less able to cope with environmental stress and are significantly more prone to birthing problems, making it ethically undesirable.

There are also several moral concerns which question the artificial mutation of the gene in slaughter animals other than cattle.

A suitable compromise is reached by crossing double muscled breeds with normal cattle types to produce heterozygous offspring, thus achieving some of the advantages of the gene without compromising the animals’ welfare. Cattle with only one copy of mutant allele do not express the extreme double-muscled appearance, but yield carcasses with 7% more beef and 14% less fat than normal cattle types, and, due to hybrid vigor, also have a higher growth rate.

These attributes are obviously enticing to the producer with respect to increased profits, but also benefit the consumer as the demand for healthy, nutritional food becomes more prevalent in today’s society.

Posted by Emily Carter

Student Number: 41209842

Primary Reference

Bellinge R.H.S. et.al, February 2005, Myostatin and its Implications on Animal Breeding – A Review, Animal Genetics, Volume 36, Issue 1, pp 1-6, URL: http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-2052.2004.01229.x

Secondary References

Elstein, D., Peabody, E., July 2004, Can You Have Your Beef And Eat It Too? Agricultural Research, viewed 29 May 2007, http://findarticles.com/p/articles/mi_m3741/is_7_52/ai_n6104326

Smith, T., 1999, Beef Leanness Gene Pinpointed, Harden, B., viewed 29 May 2007, http://www.ars.usda.gov/is/AR/archive/jun99/beef0699

Volk, E., The Myostatin Gene, viewed 30 May 2007, http://www.thinkmuscle.com/ARTICLES/volk/myostatin.htm

Turner, J., The Gene and The Stable Door – Biotechnology and Farm Animals, viewed 30 May 2007, http://72.14.253.104/search?q=cache:1-ITLgsbPD0J:bioethycs.univer.kharkov.ua/FAEM%2520ANIMFLS/The%2520Gene%2520and%2520the%2520Stable%2520Door%2520Jan%25202002.pdf+myostatin+regulation+in+slaughter+animals+%2B+moral&hl=en&ct=clnk&cd=3&gl=au

Multi-drug Resistance Gene Mutation - A Common Occurrence In Collies

Gribbles Veterinary have recently studied the multi-drug resistance gene (MDR1 gene) in collie dogs. The function of the MDR1 gene is to prevent dangerous drugs from entering the cerebral spinal fluid and negatively affecting the brain. Should the MDR1 gene be mutated the blood brain barrier is altered and hence transportation of drugs such as ivermectin is impinged.

The MDR1 gene also plays a major part in eliminating drugs from the body. When the gene is mutated drugs are not disposed of from the body as rapidly and hence a high plasma drug level ensues, as well as an increased chance of toxicity.

The antiparasitic drug ivermectin is not the only drug which has an effect on dogs with a mutated MDR1 gene. Various tranquilizers and anticancer drugs also cause problems in dogs with this mutation. When dogs with a mutated MDR1 gene are exposed to the aforementioned drugs they display severe neurological signs such as hyper salivation, tremor, ataxia, respiratory distress and in extreme cases, death.

DNA testing is a highly accurate method of checking whether or not your dog has a mutated MDR1 gene. Gribbles have devised a method of DNA testing which specifically targets the gene and can therefore be easily identified as normal or mutated. This is done from a simple cheek swab or blood test.

Some trivia: 75% of Australian collies are affected by this gene mutation.

References:
Primary:
Ÿ Gribbles Veterinary, 2006, Detecting Multi-drug Sensitivities in Dogs (MDR1 Gene Test), viewed 29/5/2007, http://www.gribblesvets.com.au/info/general/Document/get/140/documentId/

Secondary:
Ÿ Nzymes.com (Division of Biopet), 2005, Special Alert: MDR1 Gene Mutation, viewed 29/5/2007, http://www.nzymes.com/Articles/MDR1_gene_mutation.htm

The shadow pig

In the United States, there are around 60 thousand patients waiting for a suitable organ for transplantation, and around ten of them die every day for lack of organs. In order to address the problem of insufficient supply of donor organs, many groups of research have been carried out to study the possibility of developing genetically engineered pig organs for transplantation. After years of hard work, the idea has been successful to some stage, pig skin and pig valves are now used in human transplants. Normally, transplantation between humans is done by staving off the target organ related immune system with the aid of immunosuppressant drugs. However, when the technique is employed between species, more severe immune rejection will arise due to the absence of some specific sugar in human. The specific sugars will be recognized as foreign material by the circulating antibodies which results in immediate swarming and attacking of the antibodies, and ultimately, the death of the organ.
With the latest genetic engineering technology, the dream of animal organ transplantation is half way through, scientists can now create an genetically engineered pig that have reduced problem with those specific sugars, which extends the life span of the organ in the new host. This has bought the human-animal organ transplantation project a big step forward. Although a lot of ethnic issues have been run on, the genetic program is getting mature and human-animal organ transplantation will come to pass in the near future.

posted by Wing Yeung LAU, 41365690

Primary resource:
Pig-To-Human Transplants on the Horizon
- http://www.marylinstransplantpage.com/pig-human06.htm
Secondary resource:

-The Prospect of Human Cloning Raises Environmental and Ethical Issues http://proquest.umi.com.ezproxy.library.uq.edu.au/pqdweb?did=592396261&sid=1&Fmt=3&clientId=20806&RQT=309&VName=PQD
- When crops save lifes
http://www.ag-tec.com/prfinart.htm
- Cloning your bacon
http://www.crt-online.org/081700news.html

"Mommy...what is a Zorse?"

What about a wholphin? Or a Ti-tigon? What would your answer be? As suspected these are all examples of hybrid crossings: offspring from when two different, usually closely related, species are crossed.

These hybrids usually have the benefit of greater strength and endurance than their parents (like the Mule for example). More often than not the negatives, such as infertility, are overlooked. But what causes hybrid infertility? Can is be controlled?

There are basically two causes: one being the difference in chromosome number of each parent. If both parents have an equal number chromosomes but differ in amount, (62 in the donkey and 64 in the horse), the offspring will end up with an unequal chromosome number (63 in the Mule). This uneven pairing causes infertility in males.

A less likely cause could be a mutation in a certain gene pair (in any species) called Hmr (Hybrid male rescue) and Lmr (Lethal male rescue). Researchers from the Cornell University in New York suggest that the mutations occurred because of a separation of two subgroups of one species. This allowed the individual gene pairs to develop under different natural pressures. The genes then began coding for proteins that were no longer compatible in the other species. If crossed, infertility, birth defects and even death, could result.

Researches believe this new information can be used to determine how certain species are linked to their ancestors.

Certain questions as to species that do produce fertile offspring or some where only females are fertile are still being investigated.

Posted by: Elisha Mathews, 41385474


Primary Resource:

As linked to title.

Secondary Resources:

As highlighted in text

Interesting articles:

"Featherless chicken creates a flap"

Answers in Genesis: "Ligers and Wolphins? What next?" A religious view.

"Primed-n-Painted Acres": Pictures of Zorses, Donkeys and Mules.

Chickens ... the Pharmaceutical Factories of the Future?

Pharmaceutical proteins are currently synthesized by specialised bacteria. However, the proteins produced by bacteria are not exact replicas of human proteins. Scientists recently embarked on a mission to find an alternate, more accurate means of cultivating pharmaceutical proteins.

With the demand for protein based medication increasing, scientists are exploring the possibility of using the domestic chicken egg as a vessel for protein production. Chickens are a cost effective and efficient alternative to traditional methods. The resultant proteins closely resemble human proteins in their structure and arrangement of surface sugars. This increases the half life of the product and the probability of the body accepting the protein. There is also evidence to suggest that the absence of a certain sugar residue improves the cancer-destroying potential of the protein, monocal.

Human genes, selected for a specific protein, are modified in order to confine protein synthesis to the egg white. A gene-virus complex is injected, through an opening in the shell, into a male chicken embryo. The mature rooster is mated with an ordinary hen. The fertilized eggs of the daughter hens have a high protein content which can be extracted and refined for medicinal use. The primary challenge encountered by scientists was ensuring that this ability was inherited by successive generations. At present, three proteins, involved in the treatment of serious conditions such as multiple sclerosis and hairy cell leukemia, have been successfully manufactured via this method.

Posted by: Shona Richardson, 41433478

References
Primary:
Bourzac, K 2007, 'Drugs sunny-side up', viewed 30 May 2007, http://www.technologyreview.com/Biotech/18078/

Lewcock, A 2007, 'Protein production in chicken eggs cracked', viewed 25 May 2007,
http://www.in-pharmatechnologist.com/news/ng.asp?n=73404-viragen-oxford-biomedica-roslin-institute-protein-transgenic

Secondary:
Lewcock, A 2007, 'Third protein successfully expressed in transgenic chicken eggs', viewed 25 May 2007, http://www.drugresearcher.com/news/ng.asp?n=73745-oxford-biomedica-viragen-roslin-institute-protein-transgenic

Taylor, P 2005, 'Researchers make antibodies in egg whites', viewed 25 May 2007,
http://www.drugresearcher.com/news/ng.asp?n=60454-researchers-make-antibodies

Business Wire 2005, 'First production of human monoclonal antibodies in chicken eggs published in Nature Biotechnology; chicken-produced antibodies demonstrate enhanced cell killing compared to conventionally produced anti-cancer antibodies', viewed 25 May 2007,
http://findarticles.com/p/articles/mi_m0EIN/is_2005_August_29/ai_n14934651

Why Pigs 'Pig Out'

We are all familiar with the phrase “eat like a pig,” however it is uncommon to ponder the reason behind this display of gluttony we consider characteristic of pigs. Genetics has suggested that the reason behind this behaviour may lie in the genes. Geneticists have discovered that different forms of a particular gene can cause a pig to really pig out.

Various forms of a gene affecting appetite exist in pigs. One form produces leaner pigs that eat less and exhibit slower growth rates. A different form of the gene causes them to eat more and therefore grow faster and fatter. After studying the protein encoded by the malanocortin-4 receptor gene (MC4R) present in mammals, scientists discovered that altering a single amino acid subunit caused a significant variation in body fat. The replacement of the amino acid asparagine with aspartic acid produced pigs with 9% less backfat and a reduced growth rate. The suggested reason for this drastic difference is that the protein operates on the brain cells’ surface, affecting the pig’s appetite. The substitution of the single amino acid may alter the proteins capability of accepting incoming signals, thereby downgrading the hunger message.

This information can be utilized in the manipulation of economically important growth and performance traits in the pig. With the discovery of this hunger gene, genetic testing can offer a shortcut to selective breeding, giving direct information regarding the genes an animal carries and allowing farmers to identify whether a pig will make a real pig of itself.


By Zoe Sifonios
41300600


References:

Kim, S.K., Larsen, N., Short, T., Plastow, G., & Rothschild, M.F. A missense variant of the porcine melanocortin-4 receptor (MC4R) gene is associated with fatness, growth, and feed intake traits. Mamm Genome 11, 131-135 (February 2000).

Trived, B (2000) “Apetite Gene Suspected in Pigs” J. Craig Venter Institute
URL: http://www.genomenewsnetwork.org/articles/05_00/fat_gene.shtml
(date accessed: 27/5/07)

Why not take an Egg???

Once upon a time there were golden eggs...now there are pharmaceutical eggs. Sound sophisticated? Not at all!!

Chickens are being breed as pharmaceutical dispensing machines. As most pharmaceuticals are very expensive to make, there has been intense interest into developing ways of producing cheaper and faster methods. Particular interest has been on the chicken, for a few reasons. Chickens have a short breeding cycle; therefore, a pharmaceutical chicken can be produced within 5 months. Proteins can be produced exclusively in the oviduct and harvested from the eggs, without affecting the whole chicken.

Also chickens are cheap and easy to house when compared to other species such as goats or cows. The general idea behind using chickens is that valuable proteins are injected into the egg, the egg develops into a chicken and the chicken lays eggs with the particular proteins. (Yoon, 2000)

Many anti cancer drugs are required in large quantities, currently they are being produced by bacteria. Roslin Institute, creator of Dolly the Sheep, says the theory is that a cheap animal should be able to synthesize the necessary proteins faster and substantially cheaper than using bacteria in labs.

Eggs have been injected with the genetic sequence for two proteins, miR24 and human interferon beta-1a. miR24 is a cancer fighting antibody and the former has antiviral properties.

The proteins are then extracted from the eggs and used to make various products, such as antibiotics. Before this genious idea hits the road, issues such as welfare of the birds and human compatibility of the proteins need to be considered. (Cummins, 2007)

David McDougall

41184051

Primary Reference
Wayman, E. 2007, “Barnyard Pharmaceuticals”, Science, http://sciencenow.sciencemag.org/cgi/content/full/2007/116/4

Secondary Reference

Cummins, J. 2007, “Humanized Pharmaceutical Chickens”, Sustainable Agriculture Research and Education, http://lists.ifas.ufl.edu/cgi-bin/wa.exe?A2=ind0701&L=sanet-mg&P=6846

Yoon, C. 2000, “If It Walks and Moos Like a Cow, It’s a Pharmaceutical Factory”, The New York Times, Health, http://query.nytimes.com/gst/fullpage.html?sec=health&res=9404EFD81539F932A35756C0A9669C8B63

Cloning the dead

Animal species become endangered everyday, due to factors such as habitat destruction and over hunting. These threats can lead to the decrease in populations and the eventual extinction of species. Scientists are now applying cloning as a tool to increase population sizes and possibly conserve endangered species.

Cloning is the process of making a genetically identical copy of an individual. The type of cloning which has been applied to endangered species is somatic cell nuclear transfer (SCNT). In SCNT, the nucleus is removed from a somatic cell of the individual to be cloned. The nucleus of the somatic cell is then fused with an egg cell (from the individual that is to be the surrogate mother) which has had its own nucleus removed, to create a single cell clone. When the single cell clone reaches the blastocyst stage it can be inserted into the surrogate mother for gestation.

Interspecies SCNT has been used successfully to create a mouflon lamb, an endangered species of wild sheep. Researchers removed the nuclei from the cells of two female mouflons which had died earlier in the day. The nuclei were then fused with enucleate egg cells of domestic sheep and were implanted in four domestic ewes. One of the ewes completed gestation and gave birth to a cloned mouflon lamb. The mouflon lamb contained DNA from both species. The genomic DNA was identical to the original mouflon, while the mitochondrial DNA came from the domestic sheep.

The successful cloning of the mouflon using interspecies SCNT demonstrated that cloning may be a potential technique to increase populations of wildlife and assist in the conservation of endangered species.


References

Primary
Loi, P., et al. 2001. Genetic rescue of an endangered mammal by cross-species nuclear transfer using post-mortem somatic cells. Nature Biotechnology 19(October):962-964.
http://www.nature.com.ezproxy.library.uq.edu.au/nbt/journal/v19/n10/pdf/nbt1001-962.pdf

Secondary

Scientists Clone First Endangered Species: a Wild Sheep
http://news.nationalgeographic.com/news/2001/10/1025_TVsheepclone.html
Wildlife conservation and reproductive cloning
http://www.reproduction-online.org/cgi/content/full/127/3/317

Mouflon
http://en.wikipedia.org/wiki/Mouflon

Endangered sheep cloned
http://www.abc.net.au/science/news/stories/s380693.htm

Scientists Clone First Endangered Species: a Wild Sheep

http://news.nationalgeographic.com/news/2001/10/1025_TVsheepclone.html

Lauren McGrath 41211948

The problem with breeding Arab Horses.

So you want to breed an Arab horse? Why not, they are in the top 10 most popular breeds. These horses have speed, endurance and intelligence. They do however have their own genetic problems that you need to be wary of. One example is an inherited autosomal recessive disease that renders a foal without a functioning immune system, Severe Combined Immunodeficiency Disease (SCID).

The immune system includes T-lymphocytes, the cells that produce antibodies, and B-lymphocytes which are involved in cell mediated immunity. These cells are not produced by foals that have this disease. Although it is a recessive disease, it has been estimated that 25% of Arabian horses are carriers and if two of these heterozygotes are mated, there is a 25% chance of a foal being born with the disease.

Prior to 1997 the only way to know if a horse was a carrier for the disease was if it produced a SCID foal and the only way to test for the disease in the foal was through blood analysis at 4 weeks of age or post-mortem. The expected life span of these SCID foals is between one and five months. It has since been discovered that the one mutation (a loss of 6 nucleotides) on the DNA-dependent kinase, catalytic subunit gene results in a lack of B and T-lymphocytes. There is now a PCR test that can detect this shorter DNA length.
So if you’re going to breed your Arab, make sure you test for SCID.

Primary Resource:

Animal Health Trusthttp://www.aht.org.uk/clinics_equ_disord_scidm.html

Secondary Resource:

International Veterinary Information Service

http://www.ivis.org/proceedings/aaep/1997/Mcclure.pdf

Posted By: Renae Wood (41393648)

The Next Pig Thing: Animal to human transplants on the horizon.

Ever thought it possible to one day have an organ from a pig transplanted to replace a failing human organ? Well the likelihood of this doesn’t seem to be as far away as once thought, with two groups of scientists having produced cloned, genetically engineered pigs with tissue suitable for transplantation into humans – known as xenotransplantation.

Every year thousands of people die waiting for a suitable donor organ, it was therefore an automatic response to research alternative transplant options to alleviate this waiting period and ultimately save lives. But why pigs? Most importantly humans and pigs share the same size organs (approximately) and pig heart valves have been in use in human heart surgery for over 10 years with great success.

However xenotransplantation doesn’t come without its challenges, with the main technical barrier being the aggressive immune system response to foreign tissues where antibodies (of the hosts’ immune system) attach to the sugars on the surface of the transplanted organ and ultimately reject it. Scientists overcame this by knocking out the gene which encodes an enzyme (α-1,3-galactosyltransferase) necessary for attachment of these sugars to the surface of the pigs’ cells.

The scientific community is still concerned that viruses such as porcine endogenous retroviruses may be transferred across the species barrier through animal to human transplantations with potentially devastating effects on the human population. Many moral and ethical issues have also been raised concerning xenotransplantation, however if resolved this method of transplantation could have great implications in bio – medical science and on thousands of peoples’ lives.

Written by: Bethany Price

Student Number: 41206627

References:

BBC News Online, 2002. “Animal Transplants: A step closer?” Visited 23rd May, 2007 http://www.bbc.co.uk/2/hi/science/nature/1740316.stm

Dobson, R. 2002. “Scientists produce genetically engineered, cloned pigs for
Xenotransplantation.” http://www.bmj.com/cgi/content/full/324/7329/70/f Visited 23rd May, 2007.

Lee, J., Graham, W., Richard, A., Moran, C. 2002. “Characterizing and Mapping Porcine Endogenous Retroviruses in Westran Pigs” Journal Of Virology 76 (1) pg 5548 – 5556. http://jvi.asm.org/cgi/content/full/76/11/5548 Visited 25th May

Singer, E., 2006. “Pig – to – Human Transplants on the Horizon” Visited 23rd May, 2007 http://www.technologyreview.com/Biotech/17596/page2/

Wong, B., Yamada, K., Okumi, M., Weiner, J., O’Malley, P., Tseng, Y., Dor, F., Cooper, D., Saidman, S., Grismer, A., Sachs. D., “Allosensitisation Does Not Increase the Xenoreactivitiy to [alpha] 1,3 – Galactosyltransferase Gene Knockout Minature Swine in Patients on Transplantion Waiting Lists.” Journal of the Transplantation Society 82 (3) pg 314 – 319 https://www.library.uq.edu.au/ezp.php?url=http://gateway.ovid.com/ovidweb.cgi?T=JS&PAGE=fulltext&D=ovft&MODE=ovid&NEWS=N&SEARCH=0041-1337.is.%20and%202006.yr.%20and%20314.pg

Chickens laying pharmaceutical eggs?

The domestic fowl can be very good biofactories!

Chicken eggs are of special interest to pharmaceutical companies as eggs can be manipulated to produce therapeutic proteins in their whites. These manufactured proteins can be extracted and used to make pharmaceutical products. Avian eggs naturally produce large amounts of protein, mainly ovalbumin, in their albumen or egg white. (Lillico, S. G.., et. al)

The Roslin Institute, where Dolly the first mammal clone was born, have again achieved yet another milestone; this time involving transgenic chickens. Chickens have been engineered to produce proteins needed for anti-cancer drugs in their egg whites. (BBC News, 2007)

Other animals including sheep and cattle can also be genetically modified to make useful human proteins in their milk. But chickens with their shorter life cycles and egg laying ability allow them to be valuable pharmaceutical sources. The production of life-saving proteins in the egg whites of chickens may open up a pathway for faster and less costly drugs. Further advantages include the large supply of drugs that can be generated due to the considerable egg productivity, and viability to produce proteins toxic to mammalian cells. (Lillico, S. G.., et. al)

However, unlike the mammals, the egg is harder to genetically modify because it is not so transparent. This feature of the chicken egg makes viewing for injection difficult. Transgenic chickens are the result of injecting substances (e.g. DNA to make a certain protein) into the embryos. The difficult hurdle is to create a suitable environment for the extracted embryo to develop normally after the injection. (Union of Concerned Scientists, 1998)

By Michelle Wong

41194993

Primary Resources:

Lillico, S. G.., Sherman, A., McGrew, M.J., Robertson, C.D., Smith, J., Haslam, C., Barnard, P., Radcliffe, P.A., Mitrophanous, K.A., Elliot, E.A., Sang, H.M. 2007. Oviduct-specific expression of two therapeutic proteins in transgenic hens. Proceedings of the National Academy of Sciences of the United States of America, 104, pp1771-1776.

Petitte, James N., Mozdziak, Paul E. 2007. The incredible, edible, and therapeutic egg. Proceedings of the National Academy of Sciences of the United States of America, 104, pp1739-1740.

Secondary Resources:

BBC News (2007) ‘Anti-cancer chicken eggs produced.’ Accessed May, 2007.
http://news.bbc.co.uk/2/hi/science/nature/6261427.stm

Union of concerned scientists (1998). The Gene Exchange. Accessed May, 2007.
http://go.ucsusa.org/publications/gene_exchange.cfm?publicationID=271



For interest you can read about the ethical issues on transgenic chickens here:
http://www.upc-online.org/genetic/102803ge.htm

Genetically engineered pigs help in transplantation

Every year, millions of patients die while waiting for a suitable organ transplant. In order to help these people, surgery professor David Sachs discovered that genetically engineered pigs is able to provide a safe and reliable source of donor organs. (Emily S., 2006)

Pigs have a specific sugar, alpha 1, 3 galactose, attached to the pig cell which is not present in humans. (Richard B., 2002) When an ordinary pig organ is transplanted to human, antibodies circulating in the human blood immediately gather and attack the pig tissue and lead to the death of the organ or even death of the patient. (Emily S., 2006) By genetic engineering, 1, 3-galactosyltransferase (Richard B., 2002), a gene responsible for adding sugar to the cell surface, is removed. (Roger D., 2002) Pigs are also modified to a smaller size with organs that have similar size of that of humans. Transplanting organs form genetically engineered pigs would cause less stress to the human immune system after operation.

As the longest survival of animal using this method of transplant is only 83 days, the transplantation has only tried on animals but not human. Professor Sachs thinks that the procedure will be ready to try on patients, as soon as 5 years. (Emily S., 2006) It is believed that pig-to-human transplants will soon be the best solution to deal with the continuing shortage of donor organs.

Debbie Liu

41364442

Primary Reference:
Emily S., 2006, Pig-to-Human Transplants on the Horizon, Technology Review, Accessed 29-5-2007, Available at: http://www.technologyreview.com/Biotech/17596/

Secondary References:

Richard B., 2002, Cloned pigs raise transplant hopes, BBC Science Correspondent, Accessed 28-5-2007, Available at: http://news.bbc.co.uk/1/hi/sci/tech/2210306.stm

Roger D., 2002, Scientists produce genetically engineered, cloned pigs for xenotransplantation, BMJ, Accessed 28-5-2007, Available at: http://www.bmj.com/cgi/content/full/324/7329/67

Twilights Genes

On February 7 2007 leaders of the international Horse Genome Sequencing Project announced that they had successfully sequenced the genome of the domestic horse (Equus caballus). The DNA used for the project was from a Thoroughbred mare named Twilight from Cornell University in Ithaca, New York. Sequencing the horse genome began in 2006 after a 10 year effort by scientists to use genomics to identify health problems affecting horses. After $15 million from the National Human Genome Research Institute the approximately 2.7 billion base pairs of the equine genome was sequenced and made available to veterinary and biomedical researchers through public databases.
Genomics is a rapidly expanding field of biological research which sequences the genomes of many different species. The human, mouse and chimpanzees are just some of the species whose genome has been sequenced and compared. Genomics is important because it allows scientists to study evolutionary changes and to develop new ways to identify and treat disease. As well as sequencing the horse genome scientists have also produced a map of genetic variation across different horse breeds to help them distinguish which genes contribute to physical and behavioural variations. In addition to this scientists can also investigate genetic conditions found in horses, which are similar to human disorders to perhaps identify disease susceptibility.
In the coming months, scientists plan to improve the horse genome sequence and to make it more widely available. Scientists also plan to analyze the horse genome sequence and its affects on population genetics, with a view to publish these findings in the future.

Rebecca Welsh 40993265


National Human Genome Research Institute (USA)
http://www.genome.gov/20519480


Horse Genome Project
http://www.uky.edu/Ag/Horsemap/

For and against companion animal cloning

The first domestic cat was successfully cloned in 2002 and two years later the first commercially cloned cat (Little Nicky) was born. The cloning of companion animals brings with it a number of issues different to those associated with the cloning of production animals.

Those who support the cloning of companion animals, see it as an opportunity to ‘perpetuate’ the lives of their favorite pets and to cheat death to a certain extent. Compared to selective breeding, cloning gives rise to progeny which are physically identical to the parent, maintaining the characteristics which the owner or breeder finds desirable. It has also been argued that cloning companion animals may help to reduce genetic defects in future.

Animal welfare groups, however, are very opposed to the cloning of companion animals. The RSPCA holds the position that cloning to reduce genetic defects is unacceptable when those animals should simply not be bred in the first place. Whilst there may be economic advantage in cloning production animals, there is no such justification for the cloning of companion animals.

The costs associated with commercially cloning a single cat (US$50,000) also need to be balanced against the number of homeless cats and dogs and the distress that the surrogate mother and donor will have to go through.

In regards to the current commercial state of companion animal cloning, Genetic Savings and Clone Inc. was a private US company which offered cat cloning services to the general public. This company will remain famous for producing Little Nicky, however, the company closed in 2006 due to lack of demand. Presently, other companies such as ViaGen offer to gene bank pets in the event that another company offers companion animal cloning in the future.

Primary Reference:
http://news.bbc.co.uk/2/hi/science/nature/1820749.stm

Secondary References:
http://en.wikipedia.org/wiki/Little_Nicky_(cat)

http://www.rspca.org.uk/servlet/Satellite?pagename=RSPCA/RSPCARedirect&pg=biotechnology&marker=1&articleId=1125906258684
http://www.bioethics.iastate.edu/classroom/Case_of_the_Cloned_Cats.html

http://www.viagen.com/en/our-services/preserving-your-pets/

Stemming the problem.

Insulin dependant diabetes is a disease that affects both humans and animals. It is thought to be an autoimmune disease that causes the destruction of insulin producing β-Islet cells within the pancreas. Insulin is an essential hormone for regulating glucose metabolism. Therefore, an inability to produce insulin is incompatible with life. Consequently, affected animals and humans require careful administration of subcutaneous insulin to titrate circulating blood glucose levels to within acceptable limits. This is not only painful, but often extremely difficult for animal owners to administer.

Recent advances in stem cell research have highlighted stem cells as a promising future therapy for this disease. Simply put, a stem cell is a cell that has the ability to become almost any type of cell of any tissue type. Therefore, it is theoretically possible that stem cells could be harvested and manipulated to differentiate (turn into) into insulin producing B-Islet cells that could be transplanted into the pancreas. Consequently, recipient animals would no longer require the administration of insulin.

Trials have investigated the use of both embryonic and adult stem cells. Researchers have been able to manipulate/trigger the cells to differentiate into cells that resemble pancreatic β-Islets and are able to produce insulin in response to glucose. Transplantation of these cells into mice has shown some success in alleviating diabetic symptoms. These promising results indicate that with further research stem cell therapy may become a leading future therapy for the treatment of insulin dependant diabetes in both animals and humans.

Posted by Michael Valentine
Student # 41389883

Primary resources

Ibii, T, Shimada, H, Miura, S, Fukuma, E, Sato, H, Iwata, H 2007, ‘Possibility of insulin-producing cells derived from mouse embryonic stem cells for diabetes treatment’, Journal of Bioscience and Bioengineering, vol 103, pp. 140-146.
http://www.sciencedirect.com/science/article/B6VSD-4N8DJYS-6/2/5ed107e70d71165a84d228bf4589bc0b (Accessed 28/5/07)

Mastroieni, C. (2007). Stem Cells in the Treatment of Diabetes: Therapeutic Potential and Ethical Considerations. Santa Clara University: Markkula Center for Applied Ethics, http://www.scu.edu/ethics/publications/submitted/stem_cells.html (Accessed 28/5/07)

Bethesda, M. D. Stem Cells and Diabetes (2006), National Institutes of Health, U.D. Department of Health and Human Services, http://stemcells.nih.gov/info/scireport/chapter7.asp (Accessed 28/5/07)

Secondary resources

University of Wisconsin-Madison Embryonic Stem Cell Fact Sheet (2007) http://www.news.wisc.edu/packages/stemcells/facts.html#1 (Accessed 28/5/07)

Split Embryo Success

From cloning mice and sheep, the scientists of yesterday wondered if cloning humans was a possibility. In order to get as close to this goal, without breaking cloning laws, they turned to monkeys, one of our closest ancestors.

In early 1999, Tetra the Rhesus monkey was born via split embryo cloning. For the medical world, this was one step closer to human cloning. Unfortunately, this enthusiasm was not met by all, with the current ethical issues which arise from cloning such as animal rights and fear of loss of genetic diversity.


Tetra was created by split embryo. This complicated process involves creating a fertilised egg with sperm and egg from the father and mother respectively. Once the cell had reached the eight cell stage (blastula) the cells were separated and divided into groups of two and put into zonae (egg protective coating). Two of these embryos were then implanted into two different surrogate monkeys and left to grow naturally. Although one of the surrogate mother’s miscarried, the second implantation resulted in a female Rhesus monkey, Tetra.

Unlike somatic cell cloning, where the offspring will be clones of their parents, split embryo cloning results in offspring different to their parents (due to genes from both the father and mother), but all offspring from the one split egg are said to be twins, or genetically identical.

The disadvantage of this research is that the phenotype of the offspring is not know until after birth, and therefore cannot be selected for.

On the other hand, this type of research has led to similar processes happening in humans, where offspring are genetically selected for medical purposes.

Samantha Cavanagh 41290970

http://www.crystalinks.com/cloningmonkey.html
http://archives.cnn.com/2000/NATURE/01/13/monkey.cloning/
http://www.american.edu/TED/dolly.htm
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14733750

Can Babe save your bacon?

The worldwide shortage of human organ donors has led to research into xenotransplantation. Pigs organs are of a similiar size to human organs and they perform some similiar physiological functions, therefore they have become the focus of xenotransplantation research.

There are three main concerns with xenotransplantation: 1. rejection of the transplanted organ by the recipient’s immune system; 2. zoonosis; and 3. ethical and animal welfare issues.

The body’s immune system can react aggressively against the pig organ tissue, which it recognises as ‘foreign’. Hyperacute rejection (one of four types of rejection) involves human antibodies attaching to sugar molecules on the surface of pig organ cells. Thus scientists have used genetic engineering techniques to produce cloned pigs where 5 alpha1,3-galactosyltransferase (the gene responsible for making the enzyme that attaches the sugar molecules to the pig cell surface) has been knocked out.

There are also concerns that pig viruses, in particular porcine endogenous retrovirus (PERV) could be transmitted to recipients via the transplant organ. Research has yet to ascertain conclusively whether this virus can be passed to humans via xenotransplantation, and the scientific community remains divided on the issue.

Ethical debate rages because many animals are killed during xenotransplantation research experiments. Welfare groups maintain these experiments cause unacceptable suffering to animals and should be halted.

From a scientific and medical perspective, xenotransplantation is undeniably fascinating. However, humankind will have to decide whether the associated risks and ethical questions have been addressed appropriately before embracing this biotechnology.


Primary Resources

Dobson, Roger 2002, ‘Scientists produce genetically engineered, cloned pigs for xenotransplantation’ viewed 25 May 2007, http://www.bmj.com/cgi/content/full/324/7329/67. Access on-line here

Tai, HC, Zhu, X, Hara, H, Lin, YJ, Ezzelarab, M, Long, C, Ball, S, Avares, D 2007, ‘The pig-to-primate immune response: relevance for xenotransplantation.’, Xenotransplantation, 14(3):227-35. Access on-line here

Salleh, Anna 2004, ‘Pigs transplants may be safer than thought’, viewed 25 May 2007, http://www.abc.net.au/science/news/tech/InnovationRepublish_1189959.htm. Access on-line here.


Michler, Robert E 1996, ‘Xenotransplantation: Risks, Clinical Potential, and Future Prospects’ viewed 25 May 2007, http://www.cdc.gov/ncidod/EID/vol2no1/michler.htm. Access on-line here.


Secondary resources


Animal welfare website

Experimental biology website

Posted by Meghan Spencer

Dingos going to the dogs...

Dingos are facing an increasing danger of extinction, but the usual culprits of over-hunting or habitat destruction are not to blame. The purity of the dingo gene line has steadily become diluted through interbreeding with domestic dogs, and it is thought that only small, isolated pockets of pure dingos remain, and are in need of protection to ensure the preservation of the breed.

Because many dingo crosses have an appearance that is very similar to that of a purebred dingo, identification methods other than physical appearance are required. One basic method utilised is by taking skull measurements, but the most accurate method is through DNA analysis, which is used to detect specific genetic markers that are present in pure dingo lines. This method has the added benefit of being able to assess the degree of hybridisation present in any dogs identified as crossbred dingos, enabling researchers to determine how far removed they are from the purebreds.

Genetic testing has provided researchers with a tool that will assist them in identifying remaining pure dingo populations, the challenge will then be to come up with effective methods for preserving them. It would be a great shame if in the future the only place true dingos exist is in zoos, hopefully the situation will not progress that far.

Posted by: Susanne Fritz

Student No.: 40065023

References:

1. Davidson, S. 2004 "The Great Dingo Dilution", (Internet), last viewed 26 May 2007, available at: http://www.publish.csiro.au/?act=view_file&file_id=EC118p10.pdf

2. Roach, J. 2004 "Does Extinction loom for Australia's Wild Dingoes?", (Internet), last viewed 27 May 2007, available at: http://news.nationalgeographic.com/news/2004/12/1210_041210_australia_dingoes.html

3. The Australian Government Department of the Environment and Water Resources, (Internet), last viewed 28 May 2007, available at: http://www.environment.gov.au/cgi-bin/ahdb/search.pl?mode=place_detail&place_id=105848

4. UCN Redlist of Threatened Species, (Internet), last viewed 28 May 2007, available at: http://www.iucnredlist.org/search/details.php/41585/all

5. Wilton, A. 2006 "Genetic Variation in the Australian Dingo", (Internet), last viewed 27 May 2007, available at: http://www.wolfweb.com.au/acd/genvarindingo.htm (Primary Resource)

Prime steak fans rejoice as genetic engineering leads the way for safer prion free beef.

BSE (bovine spongiform encephalopathy) a.k.a mad cow disease is a fatal transmissible degenerative neurological disease which is found in bovines and is grouped into a class of diseases known as TSE (transmissible spongiform encephalopathies). The majority of evidence points to BSE being caused by an abnormal group of proteins called prions which can infect other cows either by consumption or via direct exposure into the blood stream.

The consumption of BSE infected beef by humans has been linked to another fatal degenerative brain disease known as vCJD (Variant Creutzfeldt-Jakob Disease). vCJD is a fatal disease which attacks the spinal cord and brain of humans similarly to that of BSE in cows.

Two years ago genetic engineers in the United States and Japan produced the first genetically engineered prion free Holstein cows. The scientists were able to identify and knock out the prion protein gene in each cows genetic make up. This has effectively stopped the cows from being able to produce the disease causing prions in their own tissue, even after direct exposure to BSE contaminants.

The test cattle used were all previously exposed to prion-contaminated products intravenously at the start of the study. The genetically modified cows at 20 months old were tested and recently it was declared they have all passed their health tests, officially clearing them of BSE.

These findings show a great significance to both the consumer as well as the producer. If eventually these cows were introduced into the market place they may give peace of mind to consumers of beef as well as their producers.


Written by: John Ham
Student Number: 41179552

Primary Reference:
http://news.scotsman.com/topics.cfm?tid=671&id=6152007

Secondry Reference:

http://www.macbiocom.com/pdf/HematechKirinPrPFINAL123106.pdf

Other Informative Reference Links:

http://www.who.int/mediacentre/factsheets/fs180/en/

http://www.sciencedaily.com/releases/2007/01/070101103354.htm

http://en.wikipedia.org/wiki/Bovine_spongiform_encephalopathy

http://en.wikipedia.org/wiki/Transmissible_spongiform_encephalopathy

http://learn.genetics.utah.edu/features/prions/

http://www.federationofscientists.org/PMPanels/TSE/Priprogene.asp

Urban Legend 1011: "Fishberry" Ever Existed?

The goals were to extend the growth of vegetables in Alaska and to reduce cold damage on fruits in storage. The idea was to use the anti-freeze protein gene (AFP) from an arctic flounder and insert it into the plants to adjust their sensitivity to freezing conditions. Then, the story began to circulate. People were concerned that they might be eating some gruesome "Fishberry" without knowing. Should the public worry? The answer is "No".

This gene transfer project never produced true anti-freeze plants. The experiment was conducted on corn by Dr. Fawzy Georges in Canada in 1990. The team successfully synthesized this gene and joined it to transfer plasmids. They sent these modified plasmids through the DNA impermeable cell membrane by electroporation. They made corn protoplasts produce AFP; however, the injected AFP failed to enter and protect plant's intercellular spaces due to the lack of required transport signaling DNA sequence.

Another misunderstood point is the transplant method. Although genetic code is universal in all life forms on earth; a "codon bias" exists between plant and animal species. The AFP gene experimented on plants was chemically synthesized based upon the genetic sequence of the flounder gene. Thus, the gene was not physically “extracted from a fish”; only the genetic data was taken.

In addition, strawberry was never a test subject for this research. Only a bacteria, Frostban, was successfully engineered to protect strawberries from frost damage.

In conclusion, "Fishberry" is completely fictional and never existed outside of the minds of enthusiastic researchers.

Posted By Cheng-Hsuan Chang

Primary References:

Fish-Gene Strawberries and Tomatoes. Public Issues Education Project: Genetically Engineered Organisms. (accessed 29/05/07)

J.H. Simonson 1994. Flounder Antifreeze for Plants: Article #1166. Alaska Science Forum. (accessed 29/05/07)

Secondary References:

Hightower R, Baden C, Penzes E, Lund P, and Dunsmuir P. 1991. Expression of antifreeze proteins in transgenic plants. Plant Molecular Biology 17: 1013-1021.

DeVries AL & Wohlschlag DE. 1969. Freezing resistance in some Antarctic fishes. Science 163: 1073-1075.

Davies PL & Sykes BD. 1997. Antifreeze proteins. Current Opinion in Structural Biololgy 7:828-834.

Kenward KD, Brandle J, McPherson J, and Davies PD. 1999. Type II fish antifreeze protein accumulation in transgenic tobacco does not confer frost resistance. Transgenic Research 8:105-117.