Bad breath

halitosisFoul breath—also known as halitosis—is an unpleasant condition that affects almost everyone. Because it is so widespread, determining and subsequently diagnosing each individual patient can be difficult. And it gets even harder because patients really can’t smell their own bad breath. But strong-nosed scientists have been discerning the truth bit by bit: there is now hope for those hoping to remedy their morning dragon’s breath.

Originally many believed that malodors originated in the stomach and blamed things like acid reflux, indigestion and gut flora. But what people are beginning to see is that in most cases of halitosis, the mouth is to blame. Halitosis originates from bacteria on the tongue, a condition known as tongue coating. The byproducts are largely responsible for bad breath in patients.  They produce what are known as volatile sulfur compounds (VSCs) such as hydrogen sulfide and methyl mercaptan. In order to then treat halitosis, efforts have focused on developing products that will either reduce these odiferous bacteria or neutralize the VSCs themselves.

The main form of treatment against halitosis is to simply brush the tongue to remove built-up bacteria. When halitosis persists, patients instead try to stop the creation of VSCs. By neutralizing the VSCs, the malodor does not volatilize, and the mouth does not stink. Some of the most successful neutralizing compounds have been zinc salts, chlorhexidine and hydrogen peroxide. Chlorhexidine can result in stained teeth, tongue numbness and burning; on the other hand, hydrogen peroxide can be highly oxidative and damaging to soft tissues. Zinc seems the best breath-fighting agent out there.

Zinc ions have a very high affinity for sulphur and can therefore inhibit the formation of stinky sulphur compounds by reacting with them before they leave the mouth. Zinc is also non-toxic and does not stain teeth, making it an ideal candidate to treat bad breath. While protocols to measure the efficacy of bad breath levels vary, the best measure of a persons’ breath is when the human nose smells it. And generally, these smell-tests result in accurate and reproducible results. When put to the schnoz studies show that mouthwashes, lozenges, and gums containing zinc in 0.2-0.5% are the most pleasant and effective in treating halitosis. It should not be used alone, however. A careful combination of good dental hygiene, eating plenty of fruits and vegetables, and drinking plenty of water will help minimize the smell.

Chloe Nevitt

Cellulose has a bark, but no bite!


Long chemical names on the back of food labels very frequently send people running for the hills. These “food additives” quickly get pegged as dangerous food fillers out to ruin the digestive systems and the very lives of consumers. One of these “scary” chemicals found in our daily diet is carboxymethylcellulose, also known as cellulose gum. It comes from the cell walls of plants, and is used to make paper. That’s right – trees, in your food. Sort of.

Fiber One, Pillsbury, Betty Crocker, and even Duncan Hines, whose Devil’s Food Cake mix pierces both your heart and arteries, contains cellulose gum. And while many resent the “lies” spewed by large food companies, proclaiming that additives are taking away from other “natural” ingredients, remember that every food we eat is made up of chemicals.

Apples are known to contain trace amounts of cyanide, and cassava, more commonly known in North America as tapioca, has enough cyanide to actually kill a man. And yet, there is no hesitation in eating these products. It is important to realize that the synthesis of a compound in a lab can be safer than one found in nature. Nature, more frequently than not, produces the most toxic compounds known to man.

The U.S. Food and Drug Administration, along with international organizations, regulate food additives, such as cellulose gum. After the passage of the Food Additives Amendment in 1958, any ingredient must be reviewed by the FDA to be approved as an additive.

Cellulose is an abundant, natural polysaccharide found in all plants. Cellulose gum is water-soluble gum based on cellulose. Manufactures will use an acetic acid derivative, the same acid found in vinegar, to break down the cells and form the gum. It has been used for over 50 years as a thickening agent, a stabilizer, and an emulsifier.

Gums provide many positive functions in food, without the benefit of not changing the flavor of the food to which they’ve been added. They are a good source of fiber, and can be used to reduce the calories of the food in which they’ve been added by replacing fats. They’ve provided a larger variety of foods for celiacs and other gluten sensitive individuals because those who cannot tolerate gluten can generally tolerate food gums.

Because texture, freshness, and general visual appeal all contribute to the enjoyment of food, additives aid and maintain many of the desirable aspects of food. Emulsifiers are responsible for allowing the mixing of two, usually, insoluble liquids, for example, salad dressings. And for those who believe that this is unnatural, the same result can be obtained from taking a drop from the yolk of an egg and placing it in any homemade dressing!

Ice cream, cakes, and bread all achieve better consistency, volume, and smoothness because of the addition of gums. They prevent the formation of crystals, stabilize beer foam, and help form jellies. Without pectin, another additive found from plants, there would be no Smucker’s strawberry jam, because it allows the formation of gels.

Gels and gums are just a small percent of all the additives being put into food. “Fortified foods,” which is the name given to food which has had various minerals and vitamins added to it has helped millions of people around the world. Vitamin D added to milk has helped curb rickets, a disease of the bonds. Niacin in bread and cornmeal has helped eliminate pellagra, a disease associated with the nervous system. Iodized salt has helped reduce the prevalence of goiters, or the enlargement of the thymus.

All of these food additives have helped to nearly eliminate nutritional deficiencies in the United States. They are safe and nutritious, and are added to keep consumers happy, and most importantly, healthy.


Chloe Nevitt “Making Food Better” “Food Additives” “The Street”

The Promise of Stem Cells

stem cellWe frequently hear about them on the news, they’re controversial, and their application is perhaps one of the most important advances in modern science. But what exactly are stem cells?
Most cells in our body have specialized functions. Red blood cells carry oxygen, heart muscle cells allow the heart to pump blood, bone cells support our skeleton. Stem cells are unspecialized but they do, however, give rise to all of those other cells. After a stem cell divides each new cell can either remain a stem cell or become a different cell with a specialized function, for example, muscle, brain, or liver.
Stem cells come from two sources: embryos, appropriately called embryonic stem cells, and those found in adult tissue, called adult stem cells. Embryonic stem cells come from usually four- or five-day old human embryos, generally obtained from embryos created through in vitro fertilization, a technique that generates more embryos than are needed for implantation into a prospective mother and can be donated by the donor with consent. Basically then, human embryonic stem cells are derived from donated embryos that would otherwise be discarded. Adult stem cells, on the other hand, can be found at all stages of life. These are found amongst many tissues and organs, and their primary role is to maintain and repair the tissues where they are found.
Typically, while embryonic stem cells can become any and all cell types, adult stem cells are limited to generating the cell types of the organ from which they originate, potentially regenerating the entire organ from a few cells. There is no ethical controversy about experimenting with adult stem cells but they are more difficult to isolate because they are rare in mature tissue.
Stem cells are categorized based on their potential to differentiate into other types of cells. Totipotent cells have the ability to differentiate into all possible cell types, pluripotent, the ability to differentiate into almost all cell types, and multipotent, the ability to differentiate into a closely related family of cells.
The study of stem cells, be they adult or embryonic, opens the door for all kinds of applications. Most notable is the potential for tissue regeneration. Currently, we rely on organ donors for transplants, however if stem cells can be engineered to produce new organs, then organ supply would finally meet demand. Stem cells also hold potential for the treatment of cardiovascular disease with embryonic stem cells being investigated as a potential source for regenerating damaged heart tissue.
Drug testing is another potential application. Stem cells can be differentiated into a variety of cell types which can then be used to study the effects of drugs.
Research in this area is progressing quickly. The 2012 Nobel Prize in Physiology or Medicine was awarded to. John Gurdon and Shinya Yamanaka who showed that mature cells can be changed back to embryonic-like states. This is highly significant because the technique can allow for the prolific generation of stem cells which will accelerate research..
Chloe Nevitt

A Beautiful Study: synthesis of petrol-like biofuel by Escherichia coli

Chloe Nevitt

Escherichia coliPaul Freemont of Imperial College London called it a “beautiful study.” My dad called it a load of “sciencey words.” I call it “innovation.”

John Love from the University of Exeter took DNA from the camphor tree, from soil bacteria and from blue-green algae and spliced them into the DNA of Escherichia coli bacteria. The genetically altered bacteria now were able to convert glucose into fatty acids which they then converted into hydrocarbons chemically identical to those found in gasoline. Since the original material, in this case glucose, comes from a plant source, such fuels are referred to as biofuels.

The reason biofuels are so desirable is because it means using carbon that is already in the atmosphere instead of digging up carbon that has been buried for millions of years (fossil fuels). They present an alternative: a carbon neutral cycle. It is as much a carbon sink as a carbon source. What then, does this ultimately mean?

Today, the demand for transport fuel represents 60% of global oil production. If this were 100% renewable it would mean tremendous things for the environment. Many argue that “evil” oil companies will fight against these developments for fear of lowering revenue. However, implementing this will reduce risk, cost, and competition for oil companies because simply stated; they don’t have to drill for oil anymore. These companies, such as Exxon and Chevron, have already begun investing millions in making oil from algae. This particular study was even partly funded by Shell.

Difficulties present themselves when trying to “scale-up.” Glucose is a simple monosaccharide, easy for bacteria to convert it into fatty acids. However trying to commercialize this is hard. Love and his colleagues aim to tweak the enzymes to allow the bacteria to feed on straw or animal manure. These complex compounds will undoubtedly be harder to break down. For example, lignin, a compound found in the cell walls of plants cannot currently be broken down by the genetically engineered microbes. It is also important to note the cost of making glucose.

Biofuels today are mainly algae-based. Solazyme, Inc., one of the companies at the forefront of renewable oil, uses algae to produce oils and biomaterials. Their oil has been used in jets, ships and both military and commercial purposes. The fact that there are companies in this field, and that they are doing well, is promising.

The purpose of the study was to determine whether it were possible to develop a biological route for the production of industrially-relevant alkanes and alkenes- and it was. The difficult task now remains to apply this to commercial production, but the future seems hopeful.



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