Tag Archives: Clock

Menispermum davuricum

Botanical Name : Menispermum davuricum
Family : Menispermaceae
Genus: Menispermum (men-ee-SPER-mum) (Info)
Species: davuricum

Synonyms : Menispermum dauricum (Auct.)
Common Name: Dahurian moonseed
Habitats: Menispermum davuricum is native to East AsiaSiberia to N. China. It grows on sparse forests ad bushes at the road.
Description:
Menispermum davuricum is a deciduous Climber growing to 3.6 m (11ft 10in) at a fast rate.
It is an interesting climber with attractive foliage that turns yellow in autumn. Large (10-20 cm across), heart-shaped, deep green leaves have 3-7 barely discernible lobes. Slender twining shoots densely entangle a support covering it with tiling leaves. Suitable for growing over arbours, fences, pergolas, trellises and other supports, it appreciates a site in full sun. Perfect as a screening or a ground cover plant. Prune when needed. When the plant has excessively spread out, every 3-4 years it can be cut off at 20-40cm above the ground. Spreading stolons should be kept under control.

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It is hardy to zone (UK) 4. It is in flower from Jun to July, and the seeds ripen from Oct to November. The flowers are dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required)The plant is not self-fertile.

Cultivation :
Succeeds in any moderately fertile soil that does not dry out excessively in summer, in sun or partial shade. Prefers full sun. This species is hardy to about -30°c, but, due to a lack of summer heat, the plants usually produce soft growth in mild maritime areas and this can be cut to the ground at temperatures around -5 to -10°c. The plants do not require pruning, but can benefit from being cut back to ground level every 2 – 3 years in order to keep them tidy. Closely related to M. canadense, differing mainly in its annual or rarely persistent aerial stems. A twining plant, it spreads freely by means of underground suckers. Dioecious. Male and female plants must be grown if seed is required.

Propagation :
Seed – sow late winter in a greenhouse. Two months cold stratification speeds up germination so it might be better to sow the seed as soon as it is ripe in a cold frame. Germination is usually good. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Cuttings of mature wood, autumn in a frame. Division of suckers in early spring. The suckers can be planted out direct into their permanent positions, though we prefer to pot them up and grow them on in light shade in a greenhouse or cold frame until they are established

Medicinal Uses:    The root is antirheumatic and is also used in the treatment of cancer. The whole plant is used to alleviate skin allergies and is also used in the treatment of cancer.

Known Hazards : The whole plant is poisonous

Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.

Resources:
http://e-clematis.com/en_GB/p/Menispermum-davuricum-Dahurian-Moonseed/149
http://www.pfaf.org/user/Plant.aspx?LatinName=Menispermum+davuricum
http://davesgarden.com/guides/pf/go/80723/

Guarea rusbyi

Botanical Name : Guarea rusbyi
Family: Meliaceae
Genus: Guarea
Kingdom: Plantae
Order: Sapindales

Synonym : Guarea guidonia (L.) Sleumer

Common Name :Cocillana
Other Names: Grape Bark, Guapi, Guarea guara, Guarea guidonia, Guarea spiciflora, Guarea trichilioides, Sycocarpus rusbyi, Trompillo, Upas.

Habitat : Guarea rusbyi is native to tropical Africa and Central and South America.This plant  prefers Wet soil a pH of 7 . All plants need light to allow the photosynthesis process of converting carbon dioxide to growth sugars to take place. Some plants need more sun-light than others. For this plant those sunlight conditions are well described as … Full sun

Description:
Guarea rusbyi is a large tree 20-45 m tall, with a trunk over 1 m trunk diameter, often buttressed at the base. The leaves are pinnate, with 4-6 pairs of leaflets, the terminal leaflet present. The flowers are produced in loose inflorescences, each flower small, with 4-5 yellowish petals. The fruit is a four or five-valved capsule, containing several seeds, each surrounded by a yellow-orange fleshy aril; the seeds are dispersed by hornbills and monkeys which eat the fleshy aril.

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Medicinal Uses:
Patrs used: The bark

Constituents:
An alkaloid- rusbyine. Glycoside. Resins. Volatile oil- 2.5%. Tannins.. Fixed oil. Flavonols. Anthraquinones.
G. cedrata and G. thompsonii contains limonoids, such as dreagenin and methyl 6-acetoxyangolensate. Also sesquiterpenes and glycerides.

G. glabra has pentacarbocylic triperpenoids, including glabretal.

Used widely in cough syrups in a similar way to Ipecacuanha.

Some people apply cocillana root bark directly to the skin for skin tumors.

RESEARCH
G. guidonia- from Brazil has demonstated anti-inflammatory activity in vitro and is used for that purpose.
(BHP1983,PNC).

Other Uses:
The timber is important; the African species are known as Bossé, Guarea, or Pink Mahogany, and the South American species as Cramantee or American Muskwood. It is said to possibly cause hallucinations if ingested.

Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider.

Resources:
http://en.wikipedia.org/wiki/Guarea
http://www.innerpath.com.au/matmed/herbs/Guarea_rusbyi.html
http://www.plant-supplies.com/plants/guarearusbyi.htm
http://www.webmd.com/vitamins-supplements/ingredientmono-408-COCILLANA.aspx?activeIngredientId=408&activeIngredientName=COCILLANA

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All Wound Up

Our body wants to eat, sleep and work at specific times. Scientists now know what makes the biological clock tick, writes T.V. Jayan

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All living organisms — humans are no exception — are controlled by a master clock. This biological timepiece, located in the brain, aligns an organism’s biological, behavioural and physiological activities with the day and night cycle. Its tick tock wakes us up in the morning, reminds us to eat at regular intervals and tells us when to go to bed.

But what sets this internal timekeeping, known as the circadian rhythm, has remained a mystery for long. This, despite scientists having had clues about its existence for more than a century.

The puzzle is slowly unfolding, thanks to advances in modern biology that offer a better insight into genes and their workings. Scientists now know the exact location of the master pacemaker and how is it regulated.

Research has also shown the circadian rhythm shares a reciprocal relationship with metabolism. In other words, while the circadian rhythm can influence metabolic activity, food intake can also modulate the functioning of the biological clock.

The mechanism by which feeding modulates the components of the clock machinery was discovered last month by a team of researchers led by Gad Asher of the University of Geneva. The paper, which appeared in the latest issue of Cell, shows that a protein called PARP-1 is at play here. The scientists found that mice that lack the gene that secretes PARP-1 fail to give the correct food intake cues to the circadian clock, thereby disrupting the synchronisation.

“This is an important finding,” says Raga Krishnakumar, a University of California San Francisco University researcher who, together with her former mentor W. Lee Kraus, showed early this year that PARP-1 is a multi-faceted protein that also regulates the expression of another protein which plays a vital role in aging, apart from helping contain DNA damage.

Scientists believe disruptions in the synchronisation between the circadian rhythm and metabolism play a key role in triggering many disorders that plague the modern world such as obesity, diabetes and cardiovascular diseases.

The master clock occupies a tiny area in the hypothalamus region of the brain. Called the suprachiasmatic nucleus (SCN), this brain region — the size of a grain of rice — contains a cluster of nearly 20,000 neurons. These neurons, in response to light signals received from the retina, send signals to other parts of the brain as well as the rest of the body to control a host of bodily functions such as sleep, metabolism, body temperature and hormone production.

As per the cues received through these neurons from the master clock, the cellular clocks in the tissues in different body organs are reset on a daily basis. The operation of these cellular clocks is controlled by the co-ordinated action of a limited number of core clock genes.

The year 1994 was a watershed year in research on the circadian rhythm. American Japanese scientist Joseph Takahashi, working at Northwestern University in the US, discovered the genetic basis for the mammalian circadian clock. The gene his team discovered was named CLOCK in 1997. Subsequently, scientists discovered several other genes associated with the timekeeping function such as BMAL1, PER and CRY, which are also involved in the working of the main SCN clock machinery as well as subsidiary clocks in other parts of the body.

The cues received from the master clock are important. Based on them, various genes in the cells change their expression rhythmically over a 24-hour period. It times the production of various body chemicals such as enzymes and hormones so that the body can function in an optimal fashion.

In the normal course, the body follows the master clock in setting its physiological and psychological conditions for optimal performance. While the 24-hour solar cycle is the main cue for resetting the master clock — just like a wall-mounted clock resets after a 24-hour cycle — there are other time cues as well: food intake, social activity, temperature and so on. “Unlike geophysical time, the biological clock does not follow an exact 24-hour cycle on its own. Various external and internal time cues that it receives play a vital role in bringing the periodicity close to 24 hours,” says Vijay Kumar Sharma of the Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, who has been studying the circadian rhythm for years.

However , modern society often imposes deviations from the regular work-rest cycle. “Basically, mammals including humans are diurnal (active during the day rather than at night). Whatever be the external compulsions (night shifts or partying late), the inner mechanisms of the body follow a diurnal pattern,” says Sharma. “It is bound to be out of sync if we deviate from the routine.”

“A major consequence of modern lifestyle is the disruption of the circadian rhythm. This leads to a number of pathological conditions, including sleep disturbances, depression, metabolic disorders and cancer. Studies reveal the risk of breast cancer is significantly higher in industrialised societies, and that the risk increases as developing countries become more and more westernised. Moreover, a moderate increase in the incidence of breast cancer is reported in women working nightshifts,” says Sourabh Sahar, a researcher working on the circadian rhythm at the University of California, Irvine.

Need more proof that the body has a mind of its own?

Source: The Telegraph (Kolkata, India)

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Jet Lag to be History

Scripps Research scientists say that they have determined the molecular structure of a plant photolyase protein, which is very similar  to the two proteins that control the circadian clock in humans and other mammals, moving a step closer to making jet lag history.

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The researchers claim that their study has even enabled them to test how structural changes affect the function of such proteins.

“The plant photolyase structure provides a much better model to use to study how the cryptochrome proteins in the human clock function than we have ever had before,” says Dr. Kenichi Hitomi, a postdoctoral research fellow at Scripps Research.

“It’s like knowing for the first time where the engine is in a car. When you know what the most important parts of the protein are, then you can begin to figure out how it functions,” the researchers added.

Dr. Elizabeth Getzoff, professor in the Department of Molecular Biology and member of The Skaggs Institute for Chemical Biology at Scripps Research, says that understanding how these proteins work may be helpful in fixing the clock when needed.

“In addition to decoding how the clock works, a long-term goal is to develop a drug to help people who can’t reset their clock when they need to, like people who work night shifts or travel long distances. Having the three-dimensional protein is a great step forward in both of those pursuits,” she says.

Working in collaboration with researchers from Scripps Research and from other institutions, including two universities in Japan, Hitomi studied Arabidopsis thaliana, a plant native to Europe and Asia that has one of the smallest genomes of all plants.

The researchers point out that just like all other plants, this plant also contains proteins known as photolyases, which use blue light to repair DNA damage induced by ultraviolet light.

They say that humans and mammals possess a homologous protein known as cryptochrome that modulates the circadian clock.

Getzoff says: “This is an amazing, and very puzzling, family of proteins, because they do one thing in plants and quite a different thing in mammals, yet these cousins all have the same structure and need the same cofactor, or chemical compound, to become activated.”

Hitomi adds: “All of these proteins were probably originally responses to sunlight. Sunlight causes DNA damage, so plants need to repair this damage, and they also need to respond to sunlight and seasons for growth and flowering. The human clock is set by exposure to sunlight, but also by when we eat, sleep and exercise.”

Hitomi and his colleagues set about producing proteins from the Arabidopsis thaliana genes that produce two related photolyase enzymes. These genes had been cloned earlier in the laboratory of co-author Dr Takeshi Todo of Kyoto University.

The researchers moved the gene from the plant into E coli bacteria to produce a lot of the protein, and later crystallized it to determine the atomic structure by using X-ray diffraction.

The researchers then produced a variety of mutant proteins in order to test the functional structure of the enzymes.

“We can now look at things that are the same and different between human and mouse cryptochromes and plant photolyases. Our results provide a detailed, comparative framework for biological investigations of both of these proteins and their functions,” says Hitomi.

He believes that his team’s findings may form the basis of drugs that can ease jet lag and regulate drug metabolism, as well as help better understand some fascinating circadian clock disorders that have been found in mice and man.

The study has been published in The Proceedings of the National Academy of Sciences.

Sources:The Times Of India

Going gray? Hair ‘Bleaches Itself as People Age’

Why people turn gray is no longer a gray area, for scientists have finally solved the mystery by discovering that hair bleaches itself as  people age.

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A team in Europe has found that going gray is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles. The peroxide winds up blocking the normal synthesis of melanin, our hair’s natural pigment.

According to Gerald Weissmann, the Editor-in-Chief of the ‘FASEB Journal‘, which published the study, “All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes a lot.

“We bleach our hair pigment from within, and our hair turns gray and then white. This research, however, is an important first step to get at the root of the problem, so to speak.”

In fact, the scientists made this discovery by examining cell cultures of human hair follicles. They found the build up of hydrogen peroxide was caused by a reduction of an enzyme that breaks up hydrogen peroxide into water and oxygen (catalase).

They also discovered that hair follicles could not repair the damage caused by the hydrogen peroxide because of low levels of enzymes that normally serve this function (MSR A and B).

Sources: The Times Of India

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