Arguably the oddest beast in Nature's menagerie, the platypus looks as if were assembled from spare parts left over after the animal kingdom was otherwise complete.

Now scientists know why. According to a study released Wednesday, the egg-laying critter is a genetic potpourri -- part bird, part reptile and part lactating mammal.

The task of laying bare the platypus genome of 2.2 billion base pairs spread across 18,500 genes has taken several years, but will do far more than satisfy the curiosity of just biologists, say the researchers.

"The platypus genome is extremely important, because it is the missing link in our understanding of how we and other mammals first evolved," explained Oxford University's Chris Ponting, one of the study's architects.

"This is our ticket back in time to when all mammals laid eggs while suckling their young on milk."

Native to eastern Australia and Tasmania, the semi-aquatic platypus is thought to have split off from a common ancestor shared with humans approximately 170 million years ago.

The creature is so strange that when the first stuffed specimens arrived in Europe at the end of the 18th century, biologists believed they were looking at a taxidermist's hoax, a composite stitched together from the body of a beaver and the snout of a giant duck.

But the peculiar mix of body features are clearly reflected in the animal's DNA, the study found.

The platypus is classified as a mammal because it produces milk and is covered in coat of thick fur, once prized by hunters.

But there are reptile-like attributes too: females lay eggs, and males can stab aggressors with a snake-like venom that flows from a spur tucked under its hind feet.

The bird-like qualities implied by its Latin name, Ornithorhynchus anatinus, include webbed feet, a flat bill similar to a duck's, and the gene sequences that determine sex. Whereas humans have two sex chromosomes, platypuses have 10, the study showed.

"It is much more of a melange than anyone expected," commented Ewan Birney, who led the genome analysis at the European Bioinformatics Institute in Cambridge.

The animal also possesses a feature unique to monotremes -- an order including a handful of egg-laying mammals -- called electroreception.

With their eyes, ears and nostrils closed, platypuses rely on sensitive electrosensory receptors tucked inside their bills to track prey underwater, detecting electrical fields generated by muscular contraction.

"By comparing the platypus genome to other mammalian genomes, we'll be able to study genes that have been conserved throughout evolution," said senior author Richard Wilson, a researcher at Washington University.

In the wild, they feed on worms, insect larvae, shrimps and crayfish, eating up to 20 percent of their body weight every day.

Males grow to a length of 50 centimetres (20 inches) and weigh about two kilos (4.5 pounds), with females about 20 percent shorter and lighter.

The genome sequenced for the study belongs to a female specimen from New South Wales nicknamed Glennie and can be accessed at www.ncbi.nih.gov/Genbank.

Eat Your Broccoli: OSU Study Finds Strong Anti-Cancer Properties in Cruciferous Veggies

Common name	Chemical structure	Δ^x	C:D	n−x
Myristoleic acid	CH₃(CH₂)₃CH=CH(CH₂)₇COOH	cis-Δ⁹	14:1	n−5
Palmitoleic acid	CH₃(CH₂)₅CH=CH(CH₂)₇COOH	cis-Δ⁹	16:1	n−7
Oleic acid	CH₃(CH₂)₇CH=CH(CH₂)₇COOH	cis-Δ⁹	18:1	n−9
Linoleic acid	CH₃(CH₂)₄CH=CHCH₂CH=CH(CH₂)₇COOH	cis,cis-Δ⁹,Δ¹²	18:2	n−6
α-Linolenic acid	CH₃CH₂CH=CHCH₂CH=CHCH₂CH=CH(CH₂)₇COOH	cis,cis,cis-Δ⁹,Δ¹²,Δ¹⁵	18:3	n−3
Arachidonic acid	CH₃(CH₂)₄CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CH(CH₂)₃COOH^NIST	cis,cis,cis,cis-Δ⁵Δ⁸,Δ¹¹,Δ¹⁴	20:4	n−6
Eicosapentaenoic acid	CH₃CH₂CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CH(CH₂)₃COOH	cis,cis,cis,cis,cis-Δ⁵,Δ⁸,Δ¹¹,Δ¹⁴,Δ¹⁷	20:5	n−3
Erucic acid	CH₃(CH₂)₇CH=CH(CH₂)₁₁COOH	cis-Δ¹³	22:1	n−9
Docosahexaenoic acid	CH₃CH₂CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CH(CH₂)₂COOH	cis,cis,cis,cis,cis,cis-Δ⁴,Δ⁷,Δ¹⁰,Δ¹³,Δ¹⁶,Δ¹⁹	22:6	n−3

	Saturated	Monounsaturated	Polyunsaturated	Cholesterol	Vitamin E
	g/100g	g/100g	g/100g	mg/100g	mg/100g
Animal fats
Lard	40.8	43.8	9.6	93	0.00
Butter	54.0	19.8	2.6	230	2.00
Vegetable fats
Coconut oil	85.2	6.6	1.7	0	.66
Palm oil	45.3	41.6	8.3	0	33.12
Cottonseed oil	25.5	21.3	48.1	0	42.77
Wheat germ oil	18.8	15.9	60.7	0	136.65
Soya oil	14.5	23.2	56.5	0	16.29
Olive oil	14.0	69.7	11.2	0	5.10
Corn oil	12.7	24.7	57.8	0	17.24
Sunflower oil	11.9	20.2	63.0	0	49.0
Safflower oil	10.2	12.6	72.1	0	40.68
Hemp oil	10	15	75	0
Rapeseed/Canola oil	5.3	64.3	24.8	0	22.21

(Edible plants in the family Brassicaceae (also called Cruciferae) are termed Cruciferous vegetables. For a botanical description of plants in this family (whether or not used for food), see Brassicaceae. Ten of the most common vegetables eaten by people are in a single species (B. oleracea), and are distinguished from one another taxonomically only by the infraspecific category variety. Numerous other genera and species in the family are also edible. Cruciferous vegetables are one of the dominant food crops worldwide. Widely considered to be healthful foods, cruciferous vegetables contain both soluble and insoluble dietary fiber, vitamin C and other vitamins, as well as various phytochemicals. Some research indicates that these vegetables possess healthful benefits in fighting certain diseases.)

vegetables have sulforaphane, broccoli and broccoli sprouts have the highest amount and thus could be a major player in the prevention of prostate and colon cancer.

(CORVALLIS, Ore. ) - It turns out Mom was right – you should eat your broccoli.

But what Mom may not have known is why broccoli is so healthy, and how its lesser known, younger offshoot may be a powerful anti-cancer agent.

Researchers at the Linus Pauling Institute at Oregon State University have found that sulforaphane – a compound found in cruciferous vegetables such as broccoli, bok choy and brussels sprouts – has strong anti-cancer properties.

The tiny, thread-like broccoli sprouts sold at stores next to alfalfa sprouts have more than 50 times the amount of sulforaphane than found in mature broccoli.

Emily Ho, a researcher with the Linus Pauling Institute and an assistant professor in the Department of Nutrition and Exercise Sciences at OSU, will describe these dietary inhibitors for cancer prevention at the conference on “Diet and Optimum Health,” organized by the Linus Pauling Institute.

More details on the conference, agenda, presentations and other details can be found on the web at http://lpi.oregonstate.edu/conf2007/index.html

White males born in the United States have dramatically higher rates of prostate cancer than Asian men.

But when Asian men live in the U.S. for five years or more, their rates of prostate cancer rise significantly, Ho says.

Past studies in Ho’s lab have focused on dietary elements in cancer prevention such as green tea and soy.

In her new study, which was published in the Journal of the Society of Experimental Biology and Medicine, Ho and her colleagues at Linus Pauling Institute looked at cruciferous vegetables.

While many cruciferous vegetables have sulforaphane, broccoli and broccoli sprouts have the highest amount and thus could be a major player in the prevention of prostate and colon cancer.

Ho said drugs classified as histone deacetylase (HDAC) inhibitors are being looked at as potentially preventing cancer. She said their research shows that these same effects of inhibiting HDAC might be obtained by consumption of cruciferous vegetables.

“I would say if you’re at all worried about cancer or at high risk of cancer, especially of prostate or colon cancer, then increasing your dietary intake of broccoli and other vegetables could be a good idea,” Ho said.

“It certainly can’t hurt. And drugs can have negative side effects and be difficult to administer.”

While Ho said the research is not at the point where she can make a specific recommendation on how much broccoli or bok choy to eat, she personally tries to have two servings of cruciferous vegetables a day.

In human subjects, just eating some broccoli sprouts on top of a bagel with cream cheese resulted in HDAC inhibition.

“The compound in broccoli may be one of the strongest anti-cancer fighters we have,” Ho said.

DESCRIPTION

Sulforaphane is the aglycone breakdown product of the glucosinolate glucoraphanin, also known as sulforaphane glucosinolate (SGS). Glucosinolates are beta-thioglucoside-N-hydroxysulfates and are primarily found in cruciferous vegetables (cabbage, broccoli, broccoli sprouts, brussels sprouts, cauliflower, cauliflower sprouts, bok choy, kale, collards, arugula, kohlrabi, mustard, turnip, red radish and watercress). Young broccoli sprouts and young cauliflower sprouts are especially rich in glucoraphanin.

Sulforaphane may have cancer chemopreventive activity. However, glucosinolates themselves typically have low anticancer activity. Sulforaphane is produced from sulforaphane glucosinolate via the action of the enzyme myrosinase (thioglucoside glucohydrolase), an enzyme present in cruciferous vegetables that is activated upon maceration of the vegetables.

Sulforaphane is also classified as an isothiocyanate. Its molecular formula is C₆H₁₁NOS₂, and its molecular weight is 177.29 daltons. It is also known as 4-methylsulfinylbutyl isothiocyanate and (-)-1-isothiocyanato-4(R)-(methylsulfinyl) butane. Sulforaphane glucosinolate (glucoraphanin) is also known as 4-methylsufinylbutyl glucosinolate. The structural formula is:

ACTIONS AND PHARMACOLOGY

ACTIONS

MECHANISM OF ACTION

Sulforaphane's possible anticarcinogenic activity is accounted for by its ability to induce phase II detoxication enzymes, such as glutathione S-transferase and quinone reductase [NAD(P)H: (quinone-acceptor) oxidoreductase]. These enzymes may afford protection against certain carcinogens and other toxic electrophiles, including reactive oxygen species.

PHARMACOKINETICS

Little is presently known about the pharmacokinetics of sulforaphane in humans. Some preliminary studies indicate that sulforaphane is absorbed and that it is metabolized by first undergoing conjugation with reduced glutathione to form a dithiocarbamate. The dithiocarbamate is then converted sequentially to conjugates with cysteinylglycine, cysteine and N-acetylcysteine.

INDICATIONS AND USAGE

RESEARCH SUMMARY

Sulforaphane has significantly reduced the incidence, multiplicity and rate of development of chemically induced mammary tumors in rats. It has demonstrated an ability to detoxify a number of carcinogens and thus might have the ability to protect against a variety of cancers. It has been shown that dietary supplementation with sulforaphane enhances glutathione S-transferase (GST) enzyme activity, which is known to detoxify many carcinogens.

One group of researchers has reported that three-day-old sprouts of certain broccoli and cauliflower cultivars contain 10 to 100 times higher levels of glucoraphanin, the glucosinolate of sulforaphane, than do mature broccoli and cauliflower sprouts. Thus they have concluded that "small quantities of crucifer sprouts may protect against the risk of cancer as effectively as much larger quantities of mature vegetables of the same variety." Additionally they have noted that the indole glucosinates that are prevalent in mature broccoli, for example, are present in only small quantities in the sprouts. One report suggested that the degradation products (e.g., indole-3-carbinol) of these glucosinates might themselves promote tumorigenesis, but several other investigators have not confirmed this.

CONTRAINDICATIONS, PRECAUTIONS, ADVERSE REACTIONS

CONTRAINDICATIONS

Sulforaphane is contraindicated in those who are hypersensitive to any component of a sulforaphane-containing product.

PRECAUTIONS

Pregnant women and nursing mothers should avoid sulforaphane supplementation pending long-term safety data.

ADVERSE REACTIONS

DOSAGE AND ADMINISTRATION

Sulforaphane is available in a few different formulations, usually in combination with other dietary phytochemicals. There are no typical doses.

Sulforaphane, in the form of its glucosinolate glucoraphanin, is abundant in three-day old broccoli sprouts, which are available in the marketplace. The levels of glucoraphanin in three-day old broccoli sprouts are from 10 to 100 times greater than in mature broccoli.

LITERATURE

Fahey JW, Talalay P. Antioxidant functions of sulforaphane: a potent inducer of Phase II detoxification enzymes. Food Chem Toxicol. 1999; 37:973-979.

Fahey JW, Zhang Y, Talalay P. Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens. Proc Natl Acad Sci USA. 1997; 94:10367-10372.

Faulkner K, Mithen R, Williamson G. Selective increase of the potential anticarcinogen 4-methylsulphinylbutyl glucosinolate in broccoli. Carcinogenesis. 1998; 19:605-609.

Singletary K, MacDonald C. Inhibition of benzo[a]pyrene- and 1, 6-dinitropyrene-DNA adduct formation in human mammary epithelial cells by dibenzoylmethane and sulforaphane. Cancer Letters. 2000; 155:47-54.

Zeligs MA. Diet and estrogen status: the cruciferous connection. J Med Food. 1998; 1:67-82.

Zhang Y. Role of glutathione in the accumulation of anticarcinogenic isothiocyanates and their glutathione conjugates by murine hepatoma cells. Carcinogenesis. 2000; 21:1175-1182.

Zhang Y. Talalay P, Cho CG, Posner GH. A major inducer of anticarcinogenic protective enzymes from broccoli: isolation and elucidation of structure. Proc Natl Acad Sci USA. 1992; 89:2399-2403.

Olestra (also known by its brand name Olean) is an artificial fat substance created by Procter & Gamble in 1968

Chemistry of Wood

Cellulose

Source

Cellulose is found in plants as microfibrils (2-20 nm diameter and 100 - 40 000 nm long). These form the structurally strong framework in the cell walls. Cellulose (E460) is mostly prepared from wood pulp

Structural unit

cellulose structure

Cellulose is a linear polymer of β-(14)-D-glucopyranose units in ⁴C₁ conformation. The fully equatorial conformation of β-linked glucopyranose residues stabilizes the chair structure, minimizing its flexibility (e.g. relative to the slightly more flexible α-linked glucopyranose residues in amylose). Cellulose preparations may contain trace amounts (~0.3%) of arabinoxylans.

Molecular structure

Cellulose is an insoluble molecule consisting of between 2000 - 14000 residues with some preparations being somewhat shorter. It forms crystals (cellulose I_α) where intra-molecular (O3-HO5' and O6H-O2') and intra-strand (O6-HO3') hydrogen bonds holds the network flat allowing the more hydrophobic ribbon faces to stack. Each residue is oriented 180° to the next with the chain synthesized two residues at a time. Although individual strand of cellulose are intrinsically no less hydrophilic, or no more hydrophobic, than some other soluble polysaccharides (such as amylose) this tendency to form crystals utilizing extensive intra- and intermolecular hydrogen bonding makes it completely insoluble in normal aqueous solutions (although it is soluble in more exotic solvents such as aqueous N-methylmorpholine-N-oxide (NMNO, , ~0.8 mol water/mol, then up to 30% by wt cellulose at 100°C [1060]), CdO/ethylenediamine (cadoxen), LiCl/N,N'-dimethylacetamide or near-supercritical water [1070]). It is thought that water molecules catalyze the formation of the natural cellulose crystals by helping to align the chains through hydrogen-bonded bridging.

inter and intra-molecular hydrogen bonding links in cellulose

Part of a cellulose preparation is amorphous between these crystalline sections. The overall structure is of aggregated particles with extensive pores capable of holding relatively large amounts of water by capillarity.

The natural crystal is made up from metastable Cellulose I with all the cellulose strands parallel and no inter-sheet hydrogen bonding. This cellulose I (i.e. natural cellulose) contains two coexisting phases cellulose I_α (triclinic) and cellulose I_β (monoclinic) in varying proportions dependent on its origin; I_α being found more in algae and bacteria whilst I_β is the major form in higher plants.

Cellulose I_α and cellulose I_β have the same fibre repeat distance (1.043 nm for the repeat dimer interior to the crystal, 1.029 nm on the surface [721]) but differing displacements of the sheets relative to one another. The neighboring sheets of cellulose I_α (consisting of identical chains with two alternating glucose conformers) are regularly displaced from each other in the same direction whereas sheets of cellulose I_β (consisting of two conformationally distinct alternating sheets, (as shown right where the 2-OH and 6-OH groups both change orientations so altering the hydrogen bonding pattern) each made up of crystallographically identical glucose conformers) are staggered [559]. It has been found that cellulose (I_β) significantly alters the water structuring at its surface out to about 10 Å, which may affect its enzymatic digestion [905].

Cellulose I_α and cellulose I_β are interconverted by bending during microfibril formation [418] and metastable cellulose I_α converts to cellulose I_β on annealing.

The two conformationally distinct cellulose layers in cellulose 1b

If it can be recrystalized (e.g. from base or CS₂) cellulose I gives the thermodynamically more stable Cellulose II structure with an antiparallel arrangement of the strands and some inter-sheet hydrogen-bonding. Cellulose II contains two different types of anhydroglucose (A and B) with different backbone structures; the chains consisting of -A-A- or -B-B- repeat units [627]. Cellulose III is formed from cellulose mercerized in ammonia and is similar cellulose II but with the chains parallel, as in cellulose I_α and celluloseI_β [753]. For a review of cellulose structure, see [288] or the Centre de recherches sur les macromolécules végétales web site.

Functionality

Cellulose has many uses as an anticake agent, emulsifier, stabilizer, dispersing agent, thickener, and gelling agent but these are generally subsidiary to its most important use of holding on to water. Water cannot penetrate crystalline cellulose but dry amorphous cellulose absorbs water becoming soft and flexible. Some of this water is non-freezing but most is simply trapped. Less water is bound by direct hydrogen bonding if the cellulose has high crystallinity but some fibrous cellulose products can hold on to considerable water in pores and its typically straw-like cavities; water holding ability correlating well with the amorphous (surface area effect) and void fraction (i.e. the porosity). As such water is supercoolable, this effect may protect against ice damage. Cellulose can give improved volume and texture particularly as a fat replacer in sauces and dressings but its insolubility means that all products will be cloudy.

Swelled bacterial cellulose (ex. Acetobacter xylinum), in its never-dried state with much smaller fibrils (~1%) than from plants, exhibits pseudoplastic viscosity like xanthan gels but this viscosity is not lost at high temperatures and low shear rates as the cellulose can retain its structure. Where individual cellulose strands are surrounded by water they are flexible and do not present contiguous hydrophobic surfaces. Bacterial cells may be removed by hot alkali and the clean wet cellulose used as a substrate for immobilizing biomolecules [843] or for covering wounds [844]. On drying the properties of bacterial cellulose irreversibly lose their hydrated properties and tend to those of plant cellulose.

About a third of the world's production of purified cellulose is used as the base material for a number of water-soluble derivatives with pre-designed and wide-ranging properties dependent on groups involved and the degree of derivatization (for an extensive review see [287]). Derivatizing cellulose interferes with the orderly crystal-forming hydrogen bonding, described above, so that even hydrophobic derivatives may increase the apparent solubility in water. Methyl cellulose (E461) [231] (made by methylating about 30% of the hydroxyl groups) is thermogelling, forming gels above a critical temperature due to hydrophobic interactions between high-substituted regions and consequentially stabilized intermolecular hydrogen bonding. Such gels break down on cooling In a manner similar to that causing the solubility minimum for non-polar gases; hydrophobic saccharides becoming less soluble as the temperature increases [187]. This property is useful in forming films as barriers to water loss and for holding on to small gas bubbles. Hydroxypropylmethylcellulose (HPMC, E464) has similar properties and uses but with added water interaction. Both methylcellulose and HPMC may be used in gluten-free bakery products as gluten substitutes. Hydroxypropyl cellulose (E463) possesses good surface activity but does not gel as it forms open helical coils. It is a water-soluble thickener, emulsifier and film-former often used in tablet coating. Another important derivative of cellulose is carboxymethylcellulose.

Fish oil may preserve thinking ability in elderly

High blood levels of omega-3 highly unsaturated fatty acids, found in fish oil, may help preserve thinking ability in the elderly, according to the findings of two studies published in the American Journal of Clinical Nutrition.

The results were particularly striking among subjects with high blood pressure or high cholesterol levels.

Accumulating evidence suggests that diets that include omega-3 fatty acids, specifically, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), protect against the development of dementia and Alzheimer's disease, according to a Dutch research team. However, the effect of EPA+DHA consumption on thinking ability, or "cognitive function," has received less scrutiny.

So Dr. Boukje Maria van Gelder, from the National Institute for Public Health and the Environment in Bilthoven, and associates evaluated data for 210 healthy men in the "Zutphen Study," who were 79 to 89 years old in 1990 and had normal mental capacity. Their diets were assessed in 1990, and cognitive function was tested in 1990 and again in 1995.

Subjects who ate fish had a slower decline in cognitive function than subjects who did not eat fish.

The investigators conclude that "fish consumption and EPA+DHA intake are not significantly related to cognitive impairment but are significantly related to cognitive decline."

Van Gelder's team recommends the daily consumption of roughly 400 mg of EPA and DHA, found in fish, meat, eggs, leeks, and cereal products.

In the second study, which involved 2,251 older individuals, Dr. May A. Beydoun, at the University of North Carolina at Chapel Hill, and colleagues showed that high blood levels of EPA and DHA are associated with less decline in verbal ability.

In an accompanying editorial, Dr. William E. Connor and Dr. Sonja L. Connor suggest that EPA has anti-clotting and anti-inflammatory properties that work together to help preserve cognitive function.

SOURCE: American Journal of Clinical Nutrition, April 2007.

After class on Tuesday, April 10, there was more interest in "Mark's Rule."

Markovnikov's rule (formulated by the Russian chemist Vladimir Vasilevich Markovnikov) (1870)

This is an empirical rule based on Markovnikov's experimental observations on the addition of hydrogen halides to alkenes.

The rule states that :

"when an unsymmetrical alkene reacts with a hydrogen halide to give an alkyl halide, the hydrogen adds to the carbon of the alkene that has the greater number of hydrogen substituents, and the halogen to the carbon of the alkene with the fewer number of hydrogen substituents"

This is illustrated by the following example:

example of Markovnikov's rule

Look at the position of the H and the Br in relation to the statement of Markovnikovs rule given above.

Modern mechanistic knowledge indicates reaction occurs via protonation to give the more stable carbocation:

protonation of propene can give two carbocations

Here we see that in principle, propene can protonate to give two different carbocations, one 2^o and the other 1^o.
Formation of the more stable 2^o carbocation is preferred.

The carbocation then reacts with the nucleophile to give the alkyl bromide and hence 2-bromopropane is the major product.

bromide reactions with the carbocation

A fat (a triester of glycerol and fatty acids)

Chemical structure of alpha-linolenic acid (ALA), an essential omega-3 fatty acid. Although chemists count from the carbonyl carbon (blue numbering), physiologists count from the omega (ω) carbon (red numbering). Note that from the omega end (diagram right), the first double bond appears as the third carbon-carbon bond (line segment), hence the name "omega-3"

Botanical sources of Omega-3 fatty acid

Common name	Alternate name	Linnaean name	% Omega-3
Chia	chia sage	Salvia hispanica	64%
Kiwi	Chinese gooseberry	Actinidia chinensis	62%
Perilla	shiso	Perilla frutescens	58%
Flax	linseed	Linum usitatissimum	55%
Lingonberry	cowberry	Vaccinium vitis-idaea	49%
Purslane	portulaca	Portulaca oleracea	35%
Sea Buckthorn	seaberry	Hippophae rhamnoides L.	32%
Hemp	cannabis	Cannabis sativa	20%

Peanut label

FDA Nutrition Labeling Website

Citric Acid Cycle (Krebs Cycle):

ATP:

DNA:

Fish Consumption Linked to Heart Abnormality

By Randy Dotinga
HealthDay ReporterThu May 18, 7:08 PM ET

THURSDAY, May 18 (HealthDay News) -- Putting a confusing twist on the health value of fish oil, a new study suggests that eating lots of fish may actually boost the risk of atrial fibrillation, a potentially dangerous heart condition, in certain people. However, the heavy fish eaters in the study still had a lower risk of sudden death from heart problems, and the study's lead author said the research shouldn't stop anybody from eating fish. In recent years, many doctors have urged patients to eat oily fish -- such as mackerel, herring, albacore tuna and salmon -- or take fish oil supplements. Both contain omega-3 fatty acids, which have been linked to better recovery from heart disease and a lower risk in older people of atrial fibrillation, in which the heart's electrical system malfunctions, and the muscle fails to beat in an orderly fashion. But it's not entirely clear that omega-3 fats are good for the general population without heart disease. And some research has suggested they may actually boost the risk of atrial fibrillation in certain people, such as those younger than 60. In the new study, researchers analyzed data from nearly 17,700 U.S. male doctors who took part in the Physicians' Health Study. The men answered questions about their fish consumption in 1983 and were asked in 1998 if they had developed atrial fibrillation. After adjusting the data to account for factors like existing heart disease, the researchers found that men who ate fish more than five times a week were 61 percent more likely to develop atrial fibrillation, compared to those who ate fish once a month. In total, about 7 percent of all the men in the study said they developed the condition, which is somewhat common among the elderly but rarer among younger people.

The findings were to be released Thursday at the Heart Rhythm Society's annual meeting, in Boston. What could explain the seemingly contradictory finding? It's possible that omega-3 fatty acids may actually promote the development of atrial fibrillation in younger people but prevent it in older people who have other medical conditions, said study author Dr. Anthony Aizer, an electrophysiologist at New York University Medical Center. He added that atrial fibrillation isn't as great a risk in people who don't have conditions like congestive heart disease and high blood pressure. "Younger people are significantly less likely to have these additional medical conditions," he said. "As a result, the risk in younger people as a whole is likely to be significantly lower." Aizer acknowledged that the study didn't rely on "gold standard" methods, such as double-blind, placebo-controlled research. So, it's possible that another unknown factor could explain the rise in atrial fibrillation cases seen in study participants, he said.

That possibility makes sense to Dr. Marie-Noelle Langan, chief of electrophysiology at Lenox Hill Hospital in New York City. She said it's possible that the male doctors who ate a lot of fish each week were health-minded athletes, who can be prone to atrial fibrillation. "It's possible this is a group of very fit people who run like maniacs," Langan said. "It doesn't take that many patients to throw off the statistics." Langan's hospital plans to launch its own study into fish oil and atrial fibrillation.

So should you take fish oil supplements or eat a lot of oily fish? "There is no evidence that it's dangerous for your life," said Dr. Francesco Santoni, who's also an electrophysiologist at Lenox Hill Hospital. However, "it's unclear what effect it has in the general population on arrhythmias," or heart rhythm disturbances. Aizer had similar views. "The message of this study is not to stop eating fish," he said. "Fish may have different effects on different people. Lifestyle and dietary habits need to be tailored on an individual basis to promote overall health." For now, he said, "clearly, more investigation is needed to reach a more definitive answer about the multiple effects of omega-3 fatty acid on the heart's electrical function."

More information: Here's what the American Heart Association has to say about omega 3 fatty acids.

More reasons to cut back on saturated fats
They affect not only cholesterol, but can also raise risk of cancer, diabetes

MSNBC

Updated: 7:06 a.m. PT May 19, 2006

Recent studies remind us that the goal of eating less fat should focus on saturated fat. In the past, experts warned against saturated fat because of its direct relationship to LDL (“bad”) blood cholesterol and heart disease risk.

Now research suggests that too much saturated fat may be problematic, even if your cholesterol isn’t high, because of its possible effects on insulin functions, potentially raising the risk of diabetes, cancer, ovarian disorders and other health problems.

Surveys suggest that American adults consume on average about 12 percent of their calories from saturated fat. However, the Advisory Committee for the 2005 Dietary Guidelines for Americans recommended a maximum target of 10 percent of calories for most adults.

This target translates to 20 grams (g) per day for the average adult, which you can calculate by adding grams of saturated fat listed on food labels. People who are smaller, less active, or trying to lose weight, would have an 18 g daily limit, while those with higher calorie needs could eat 24 or 25 g per day.

The traditional way of seeing whether these suggested limits reduce a person’s saturated fat intake enough has been by measuring LDL blood cholesterol levels. Each percentage-point drop in saturated fat consumption generally reduces LDL by one to two percent.

Cutting saturated fat from the current average to 10 percent would lower blood cholesterol by two to four percent. People whose blood cholesterol levels remain high even while meeting this goal may need to reduce their saturated fat intake even further, which would mean a maximum of 12 to 18 g per day.

Insulin problems
One of the new studies that links saturated fat consumption with problems in proper functioning of insulin suggests that initially too much saturated fat might decrease the pancreas’s secretion of insulin. Less insulin might then cause a chain of events that leads to over-production of insulin, resistance to its functioning and ultimately to the most common form of diabetes.

When high insulin levels become established, a host of other problems seem to develop. One problem is polycystic ovarian syndrome (PCOS), which can cause fertility problems, irregular menstrual cycles and skin problems. An estimated 6 to 10 percent of all women have PCOS. Other problems include an increased risk of some cancers and possibly increased cognitive problems similar to Alzheimer’s disease.

Although these consequences could make you afraid to eat any saturated fat, studies seem to show that the cancer risk relates mainly to very high levels of saturated fat. For now, you should simply aim for amounts that keep your blood cholesterol healthy.

To reach the recommended levels of saturated fat, on average Americans need to cut 5 to 10 grams of it from their daily food choices.

There are many ways to achieve this reduction. Each time you exchange a deck-of-cards-sized portion of a higher-fat red meat for lean red meat, seafood or skinless chicken, you cut at least 5 grams of saturated fat. If your meat portions are larger than a deck of cards, reducing them to this size will eliminate even more. For each ounce of regular cheddar or other high-fat cheese you replace with lowfat cheeses, you slash saturated fat by 5 grams. A cup of 1 percent or skim milk instead of whole milk will save you 3 to 5 grams. Two teaspoons of soft margarine or olive oil instead of butter will get rid of more than 3 grams.

These small changes may give you far more than better blood cholesterol. You may find yourself enjoying better overall health.

DNA Figures and Discussion

Components of DNA

DNA is a polymer. The monomer units of DNA are nucleotides, and the polymer is known as a "polynucleotide." Each nucleotide consists of a 5-carbon sugar (deoxyribose), a nitrogen containing base attached to the sugar, and a phosphate group. There are four different types of nucleotides found in DNA, differing only in the nitrogenous base. The four nucleotides are given one letter abbreviations as shorthand for the four bases.

A is for adenine
G is for guanine
C is for cytosine
T is for thymine

Purine Bases

Adenine and guanine are purines. Purines are the larger of the two types of bases found in DNA. Structures are shown below:

Structure of A and G

The 9 atoms that make up the fused rings (5 carbon, 4 nitrogen) are numbered 1-9. All ring atoms lie in the same plane.

Pyrimidine Bases

Cytosine and thymine are pyrimidines. The 6 stoms (4 carbon, 2 nitrogen) are numbered 1-6. Like purines, all pyrimidine ring atoms lie in the same plane.

Structure of C and T

Deoxyribose Sugar

The deoxyribose sugar of the DNA backbone has 5 carbons and 3 oxygens. The carbon atoms are numbered 1', 2', 3', 4', and 5' to distinguish from the numbering of the atoms of the purine and pyrmidine rings. The hydroxyl groups on the 5'- and 3'- carbons link to the phosphate groups to form the DNA backbone. Deoxyribose lacks an hydroxyl group at the 2'-position when compared to ribose, the sugar component of RNA.

Structure of deoxyribose

Nucleosides

A nucleoside is one of the four DNA bases covalently attached to the C1' position of a sugar. The sugar in deoxynucleosides is 2'-deoxyribose. The sugar in ribonucleosides is ribose. Nucleosides differ from nucleotides in that they lack phosphate groups. The four different nucleosides of DNA are deoxyadenosine (dA), deoxyguanosine (dG), deoxycytosine (dC), and (deoxy)thymidine (dT, or T).

Structure of dA

In dA and dG, there is an "N-glycoside" bond between the sugar C1' and N9 of the purine.

Nucleotides

A nucleotide is a nucleoside with one or more phosphate groups covalently attached to the 3'- and/or 5'-hydroxyl group(s).

DNA Backbone

The DNA backbone is a polymer with an alternating sugar-phosphate sequence. The deoxyribose sugars are joined at both the 3'-hydroxyl and 5'-hydroxyl groups to phosphate groups in ester links, also known as "phosphodiester" bonds.

Example of DNA Backbone: 5'-d(CGAAT):

Features of the 5'-d(CGAAT) structure:

Alternating backbone of deoxyribose and phosphodiester groups
Chain has a direction (known as polarity), 5'- to 3'- from top to bottom
Oxygens (red atoms) of phosphates are polar and negatively charged
A, G, C, and T bases can extend away from chain, and stack atop each other
Bases are hydrophobic

DNA Double Helix

DNA is a normally double stranded macromolecule. Two polynucleotide chains, held together by weak thermodynamic forces, form a DNA molecule.

Structure of DNA Double Helix

Features of the DNA Double Helix

Two DNA strands form a helical spiral, winding around a helix axis in a right-handed spiral
The two polynucleotide chains run in opposite directions
The sugar-phosphate backbones of the two DNA strands wind around the helix axis like the railing of a sprial staircase
The bases of the individual nucleotides are on the inside of the helix, stacked on top of each other like the steps of a spiral staircase.

Base Pairs

Within the DNA double helix, A forms 2 hydrogen bonds with T on the opposite strand, and G forms 3 hyrdorgen bonds with C on the opposite strand.

Example of dA-dT base pair as found within DNA double helix

Example of dG-dC base pair as found within DNA double helix

dA-dT and dG-dC base pairs are the same length, and occupy the same space within a DNA double helix. Therefore the DNA molecule has a uniform diameter.
dA-dT and dG-dC base pairs can occur in any order within DNA molecules

DNA Helix Axis

The helix axis is most apparent from a view directly down the axis. The sugar-phosphate backbone is on the outside of the helix where the polar phosphate groups (red and yellow atoms) can interact with the polar environment. The nitrogen (blue atoms) containing bases are inside, stacking perpendicular to the helix axis.

View down the helix axis

The components

The deoxyribonucleic acid, DNA, is a long chain of nucleotides which consist of (figure 1):

Deoxyribose (a pentose = sugar with 5 carbons)
Phosphoric Acid
Organic (nitrogenous) bases (Purines - Adenine and Guanine, or Pyrimidines -Cytosine and Thymine)

Figure 1: A nucleotide.

Note: in a nucleotide, the atoms of the organic base are numbered 1, 2, ... and the atoms of the sugar, wether it is a deoxyribose like in DNA or a ribose like in RNA, are numbered 1', 2', 5'. Atoms in the sugar component of a nucleotide provide the link between the base and the phosphate group. The 1' carbon is attached to the 9 nitrogen of a purine, or the 1 nitrogen of a pyrimidine. The OH (hydroxyl) group on the 5' carbon is replaced by a bond to the phosphate group (ester bond).

DNA consists of two associated polynucleotide strands that wind together in a helical fashion. It is often described as a double helix.

Each polynucleotide is a linear polymer in which the monomers (deoxynucleotides), are linked together by means of phosphodiester bridges , or bonds. These bonds link the 3' carbon in the ribose of one deoxynucleotide to the 5' carbon in the ribose of the adjacent deoxynucleotide. This is illustrated in Figure 2 .

Figure 2: A segment of a single nucleic acid chain : this is a clickable MAP . On the right, is shown the double helix of DNA which is the normal state of the molecule.

Figure 3: The two sugar backbones are oulined in dark grey
deoxyadenylate (A) is in blue,
deoxythymidylate (T) is in green,
deoxyguanylate (G) is in red,
deoxycytidylate (C) is in orange,

Notice that

The sugar / phosphate backbone is on the outside while the organic bases project into the inside of the double helix.
The organic bases stack on top of each other in parallel plans.
By convention a polynucleotide is read from the 5' end to the 3' end.
The orientations of the two strands are antiparallel : their 5' - 3' directions are opposite.

The two strands are held together by the energy of many hydrogen bonds and hydrophobic interaction. The base pairing is regular and precise.

Figure 4: Base pairing. The hydrogen bonds between the NH (blue) and O (red) are in green.

Naming nucleosides and nucleotides:


Definitions	Bases
	Adenine (A)	Guanine (G)	Cytosine (C)	Thymine (T)
The combination of a deoxyribose and a base constitutes a deoxynucleoside .	Deoxyadenosine	Deoxyguanosine	Deoxycytidine	Deoxythymidine
The combination of a phosphate, a deoxyribose and a base constitutes a deoxynucleotide.	Deoxyadenylate	Deoxyguanylate	Deoxycytidylate	Deoxythymidylate

DNA : some facts...

DNA is a double helix.
The Watson and Crick model of a double helix structure provides an answer to the regularity of the composition in bases and its physiological properties (replication in the cell). It is confirmed by diffraction data.
The base composition is variable, but in all cases the amount of adenine is equal to the amount of thymine (A=T). In the same manner, C=G. Consequently A+C= T+G .
E. coli has a single circular DNA molecule of 4,600,000 base pairs. The total length is 1.4 mm.
In man, the DNA molecule in a diploid cell, if fully extended, would have a total length of 1.7 metres. If you unwrap all the DNA you have in all your cells, you could reach the moon ...6000 times!
In addition to functioning as building blocks of nucleic acids, nucleotides are important because they are used to store and transfer chemical energy (e.g. ATP)

What's in a name

D	Deoxyribo : the pentose does not have any oxygen in position 2.
N	Nucleic: these molecules were first found in the nucleus of the cell , before being found in mitochondria, chloroplasts (of plant cells), and in the cytoplasm of prokaryotes.
A	Acid: only two of the three acid groups of the phosphoric acid are used to form the DNA chain. The third one gives the phosphoribo-backbone an acidic property.

ATP (ADENOSINE-5'-TRIPHOSPHATE):

Structure of ATP and Conversion of ATP to ADP

A good summary on the properties, structure and reactions of amines is found here

Tollen's Test for aldehydes. 1 mL of freshly prepared Tollen's Reagent was added to p-tolualdehyde. A positive test is observed for an aldehyde, but not for a ketone.

The following material has been placed on Reserve:

INSTRUCTOR   Nafshun, Richard    COURSE       CH 130
TITLE/LOCATION/CALL NUMBER        AUTHOR/STATUS
Fundamentals of general,organic,and bilo      McMurry                   Valley Reserves VR101
Test Item File                                                   McMurry                   Valley Reserves VR 102

Ball-and-stick models of the first ten linear alkanes:

Formula	Name	Structure
CH₄	Methane
C₂H₆	Ethane
C₃H₈	Propane
C₄H₁₀	Butane
C₅H₁₂	Pentane
C₆H₁₄	Hexane
C₇H₁₆	Heptane
C₈H₁₈	Octane
C₉H₂₀	Nonane
C₁₀H₂₂	Decane

Constitutional Isomers of Alkanes.doc

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DESCRIPTION

ACTIONS AND PHARMACOLOGY

ACTIONS

MECHANISM OF ACTION

PHARMACOKINETICS

INDICATIONS AND USAGE

RESEARCH SUMMARY

CONTRAINDICATIONS, PRECAUTIONS, ADVERSE REACTIONS

CONTRAINDICATIONS

PRECAUTIONS

ADVERSE REACTIONS

DOSAGE AND ADMINISTRATION

LITERATURE

Drug Name: Ritalin LA (methylphenidate HCl)

General Information

Clinical Results

Side Effects

Mechanism of Action

Chemistry of Wood

Cellulose

Fish oil may preserve thinking ability in elderly

Botanical sources of Omega-3 fatty acid

Fish Consumption Linked to Heart Abnormality

Components of DNA

Purine Bases

Structure of A and G

Pyrimidine Bases

Structure of C and T

Deoxyribose Sugar

Structure of deoxyribose

Nucleosides

Structure of dA

Nucleotides

DNA Backbone

Example of DNA Backbone: 5'-d(CGAAT):

Features of the 5'-d(CGAAT) structure:

DNA Double Helix

Structure of DNA Double Helix

Features of the DNA Double Helix

Base Pairs

Example of dA-dT base pair as found within DNA double helix

Example of dG-dC base pair as found within DNA double helix

DNA Helix Axis

View down the helix axis

The components

DNA : some facts...

What's in a name

Structure of ATP and Conversion of ATP to ADP

Formula

Name

Structure

CH4

Methane

C2H6

Ethane

C3H8

Propane

C4H10

Butane

C5H12

Pentane

C6H14

Hexane

C7H16

Heptane

C8H18

Octane

C9H20

Nonane

C10H22

Decane

CH₄

C₂H₆

C₃H₈

C₄H₁₀

C₅H₁₂

C₆H₁₄

C₇H₁₆

C₈H₁₈

C₉H₂₀

C₁₀H₂₂