Jan. 23, 2013 ? New research by the University of Southampton has found a mechanism as to how corals use their pink and purple hues as sunscreen to protect them against harmful sunlight.
Many reef corals need light to survive, as they benefit from sugars and lipids that are produced by their light-dependent symbiotic algae. However, in the shallow water of coral reefs, light levels are often higher than required by the corals, so paradoxically, the vital sunlight can become harmful for the algae and their hosts.
Apart from temperature, light stress is a major driver of coral bleaching -- the loss of the symbiotic algae that represents a threat to coral reef survival.
Working in the Great Barrier Reef and under tightly controlled conditions in the Coral Reef Laboratory of the University of Southampton, the team of researchers produced experimental evidence that the pink and purple chromoproteins can act as sunscreens for the symbiotic algae by removing parts of the light that might become otherwise harmful.
Dr J?rg Wiedenmann, Senior Lecturer of Biological Oceanography and Head of the University's Coral Reef Laboratory, who led the study says: "The beautiful pink and purple hues that are produced by the coral host are often evoked by chromoproteins; pigments that are biochemically related to the green fluorescent protein (GFP) of the jellyfish Aequorea victoria. In contrast to their green glowing counterpart, the chromoproteins take up substantial amounts of light, but they don't re-emit light.
"GFP-like proteins were suggested to contribute to the protection of corals and their symbionts from excess sunlight. This hypothesis has been controversially discussed as the mechanism as to how these pigments function remained unclear. At least for the chromoproteins we know now that they have indeed the capacity to fulfill this function." The researchers also proposed an explanation for the mysterious phenomenon that some corals accumulate exceptionally high amounts of chromoproteins in growing areas, such as branch tips or in the region of healing wounds.
Dr Wiedenmann, who is based at the National Oceanography Centre, Southampton, explains: "These growing areas contain essentially no symbiotic algae, so much of the light is reflected by the white coral skeleton instead of being used by the algae. The resulting increased light intensities in the new parts of the coral represent a potential danger for the algal cells that need to colonise these areas. Hence, it seems that the corals use a clever trick to help their symbionts. The higher light intensity switches on the genes that are responsible for the production of the sunscreening chromoproteins.
"Our results suggest that the screening effect of the chromoproteins could help the algae to enter the new tissue. Once the symbiont population is fully established, the light levels in the tissue decrease as the algae use most of the light for photosynthesis. As a consequence, the genes of the chromoproteins are switched off again which allows the coral to save the energy required for their production."
The research contributes to a better understanding of the coral's response to environmental stress. Knowledge of the stress resilience of corals is an important requirement to help predictions of the fate of coral reefs that are exposed to climate change and various forms of anthropogenic disturbance.
The paper is published in the latest edition of the journal Coral Reefs.
Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:
Story Source:
The above story is reprinted from materials provided by University of Southampton.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
E. G. Smith, C. D?Angelo, A. Salih, J. Wiedenmann. Screening by coral green fluorescent protein (GFP)-like chromoproteins supports a role in photoprotection of zooxanthellae. Coral Reefs, 2013; DOI: 10.1007/s00338-012-0994-9
Note: If no author is given, the source is cited instead.
Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.
More than 50 percent of Americans believe abortion should legal in all or most cases while 70 percent want the landmark Supreme Court ruling of Roe v. Wade to be upheld, according to an NBC News/Wall Street Journal poll released Monday night.
Fifty-four percent said abortion should be legal either always or most of the time, marking the first time since the question was included in the NBC/WSJ poll in 2003 that a majority believes it should be legal. Thirty-one percent indicated that abortion should always be legal, while 23 percent said it should be legal most of the time.
The 70 percent who said that Roe should be protected included 57 percent who feel strongly about upholding the decision. Only 24 percent said the decision should be overturned.?
Monday's poll was released on the eve of the 40th anniversary of Roe. A?survey released last week from Pew?showed that a comparably large majority of 63 percent does not want the historic 1973 ruling reversed.?
Jan. 22, 2013 ? In research published in the Jan. 17 issue of The Journal of Cell Biology, a team led by Susana Gonzalo, Ph.D., assistant professor of biochemistry and molecular biology at Saint Louis University, has discovered a molecular pathway that contributes to triple-negative breast cancer, an often deadly and treatment resistant form of cancer that tends to strike younger women. In addition, Gonzalo and her team identified vitamin D and some protease inhibitors as possible new therapies and discovered a set of three biomarkers that can help to identify patients who could benefit from the treatment.
In the recent breakthrough, which was funded in part by a $500,000 Department of Defense grant, Gonzalo's lab identified one pathway that is activated in breast cancers with the poorest prognosis, such as those classified as triple-negative. These cancers often strike younger women and are harder to treat than any other type of breast cancer. Women who are born with BRCA1 gene mutations are at increased risk for developing breast and ovarian cancers within their lifetime, and the tumors that arise are frequently the triple-negative type. Although chemotherapy is the most effective treatment for triple-negative breast cancer, it has profound secondary effects. Understanding the biology of triple-negative breast cancers will help to develop less toxic therapeutic strategies.
The Science
Experiments performed in Gonzalo's laboratory, in collaboration with the laboratories of Xavier Matias-Guiu and Adriana Duso (IRBLleida, Spain), showed that activation of this novel pathway not only allows tumor cells to grow unchecked, but also explains the reduced sensitivity of these types of tumors to current therapeutic strategies. Importantly, vitamin D plays a role in turning off this pathway, providing a safe and cost-effective strategy to fight these types of tumors.
For molecular biologists like Gonzalo who look for answers below the cellular level to discover why some people develop cancer, the search often involves tracing a chain of events to try to understand cause and effect of the behavior between several genes and the proteins which they express. In order to understand these complex pathways, researchers often turn levels of proteins on or off by expressing one gene or suppressing another. Part of a researcher's challenge is determining what the function of each component of a pathway is.
The cell employs a complex mechanism to protect genetic information and ensure that damaged DNA is not passed on to daughter cells. Cells have built in checkpoints and fail safes to ensure the accuracy of their DNA code and are able to slow or stop their own proliferation if the information is compromised. Loss of these checkpoints and the accumulation of damaged DNA often leads to cancer.
The Pathway
BRCA1 is a well-established tumor suppressor gene. Women who carry mutations in this gene have a high risk of developing breast and ovarian cancer. Tumors that arise often lack expression of three receptors: estrogen, progesterone and HER2 (thus, "triple-negative"), and do not respond to hormone therapy.
BRCA1 is important because it is involved in repairing DNA double-strand breaks, a kind of DNA damage that is especially dangerous for the integrity of our genome. BRCA1 also is involved in cell-cycle checkpoints after damage, which are control mechanisms during cell proliferation that make sure the DNA information has been accurately replicated and transferred to the daughter cells. Thus, BRCA1 is considered a safeguard of the genome.
Loss of BRCA1 is bad news for the information contained in a cell's genetic blueprint. It results in genomic instability characterized by unrepaired DNA breaks and chromosomal aberrations that compromise cell viability. How BRCA1-mutated cells are able to form tumors has been a long-standing question. Investigators recently showed that loss of another DNA repair factor, 53BP1, allows proliferation and survival of BRCA1-deficient cells. In addition, decreased levels of 53BP1 were observed in triple-negative breast cancers, and correlated with resistance to drugs at the forefront of cancer treatment, such as PARP inhibitors.
Gonzalo's team has found a pathway responsible for the loss of 53BP1 in breast cancers with poor prognosis, specifically BRCA1 mutated and triple-negative. It turns out that loss of BRCA1 increases the expression of a protease, known as cathepsin L (CTSL), which causes the degradation of 53BP1. Cells that have lost both BRCA1 and 53BP1 have the ability to repair DNA, maintain the integrity of the genome, and proliferate. Thus, the protease helps cells with faulty BRCA1 to survive.
The Fix
If lowering the levels of 53BP1 allows BRCA1 deficient cells to thrive and do their worst, increasing the levels of the protein offers a promising strategy for treatment of breast tumors.
So, how to do this? In previous research, Gonzalo's team showed that vitamin D inhibits CTSL-mediated degradation of 53BP1 in non-tumor cells, as efficiently as specific CTSL inhibitors. This time, they found that treatment of BRCA1-deficient tumor cells with vitamin D restores high levels of 53BP1, which results in increased genomic instability and reduced proliferation. Importantly, their evidence suggests that vitamin D treatment might restore the sensitivity to PARP inhibitors in patients who become resistant. Thus, a combination of vitamin D and PARP inhibitors could represent a novel therapeutic strategy for breast cancers with poor prognosis.
So, with this chain of events, Gonzalo and colleagues demonstrated a pathway by which triple-negative breast cancers proliferate: BRCA1-deficient cells activate CTSL which minimizes levels of 53BP1 to overcome genomic instability and growth arrest.
The Patients
In a final exceptionally useful discovery, Gonzalo and collaborators found that high levels of nuclear CTSL and low levels of 53BP1 and nuclear vitamin D receptor (VDR) are a clear marker that identifies certain triple-negative breast cancer patients, biomarkers that offer the potential to customize future breast cancer therapies. In particular, this triple-biomarker signature will allow the identification of patients in whom the pathway is on and who might benefit the most from vitamin D treatment.
Bottom Line
Researchers have discovered a way in which one of the deadliest and most difficult to treat breast cancers allows tumor cells to grow unchecked and how these tumors resist treatment. Specifically, they found that BRCA1-deficient cells activate CTSL which leads to lower levels of the protein 53BP1 which, in turn, allows cancer cells to grow unchecked.
? In addition, they discovered the potential for a new therapy involving vitamin D, and identified biomarkers that can help identify which patients could benefit from this therapy.
? In the future, women with triple-negative breast cancer may benefit from a treatment that includes vitamin D. As with all laboratory research, vitamin D therapy will have to be studied in a clinical trial before doctors know how safe or effective it will be.
? Researchers' next steps will be to study molecular mechanisms behind the activation of the degradation of 53BP1 by CTSL. In addition, preclinical studies with vitamin D and cathepsin inhibitors as single agents or in combination with different drugs are underway in mouse models of breast cancers.
Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first medical degree west of the Mississippi River. The school educates physicians and biomedical scientists, conducts medical research, and provides health care on a local, national and international level. Research at the school seeks new cures and treatments in five key areas: cancer, liver disease, heart/lung disease, aging and brain disease, and infectious disease.
Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:
Story Source:
The above story is reprinted from materials provided by Saint Louis University Medical Center.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
D. A. Grotsky, I. Gonzalez-Suarez, A. Novell, M. A. Neumann, S. C. Yaddanapudi, M. Croke, M. Martinez-Alonso, A. B. Redwood, S. Ortega-Martinez, Z. Feng, E. Lerma, T. Ramon y Cajal, J. Zhang, X. Matias-Guiu, A. Dusso, S. Gonzalo. BRCA1 loss activates cathepsin L-mediated degradation of 53BP1 in breast cancer cells. The Journal of Cell Biology, 2013; 200 (2): 187 DOI: 10.1083/jcb.201204053
Note: If no author is given, the source is cited instead.
Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.
The latest company to launch into the asteroid-mining business isn't worried about competition from its biggest rival, saying that the resources of deep space are vast enough to support a bustling new industry off Earth's surface.
The new company, Deep Space Industries, Inc., announced today (Jan. 22) that it plans to mine asteroids for metals, water and other resources, with the goal of helping humanity spread throughout the solar system. Another company with similar goals, the billionaire-backed Planetary Resources, unveiled its own plans last April.
Both companies can coexist and prosper, Deep Space officials said during a press conference today.
"We love Planetary Resources," Deep Space chairman Rick Tumlinson said. "Space is big. There's room for everybody."
Deep Space and Planetary Resources will go after near-Earth asteroids,?many of which are rich in water and a variety of different metals.
Both firms aim to split asteroid water into its constituent hydrogen and oxygen, which are the chief components of rocket fuel. Asteroid-derived propellant could be dispensed from off-planet "gas stations," allowing satellites and journeying spacecraft to top up their tanks cheaply and efficiently.
Such off-Earth depots could extend the lives of satellites and make manned trips to far-flung destinations like Mars much more economically viable, advocates say.
The metals and other materials, meanwhile, could be used to construct habitats, solar-power satellites and other spacecraft, potentially jump-starting an in-space manufacturing industry. Precious metals such as platinum and gold could also be delivered to Earth for terrestrial use.
So far, astronomers have identified more than 9,000 near-Earth asteroids, with about 1,000 being added to the rolls every year. Such numbers suggest there are more than enough to keep two mining companies busy for a long time, Deep Space officials said.
"There are two or three million near-Earth asteroids," said Deep Space CEO David Gump. "There's room for everyone to prosper, I think."
The startup of two asteroid-mining firms ? along with the rise of private spaceflight companies such as California-based SpaceX ? is a sign that humanity may finally be taking real steps toward the long-held dream of permanent space settlement, Tumlinson said.
"One company may be a fluke," he said. "Two companies showing up? That's the beginning of an industry."
Follow SPACE.com senior writer Mike Wall on Twitter @michaeldwall?or SPACE.com @Spacedotcom. We're also on Facebook?and?Google+.?
Copyright 2013 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Contact: Fred Lewsey fred.lewsey@admin.cam.ac.uk 07-885-798-680 University of Cambridge
Endangered Mexican howler monkeys are consuming more leaves and less fruit as a result of habitat disturbance by humans, which is forcing them to invest much more time foraging for sustenance and leading to increased 'stress' levels, as detected through hormone analysis.
The research, published today in the International Journal of Primatology, took place in the tropical rainforests of the Mexican state of Veracruz, which are being deforested and fragmented by human activity - primarily the clearing of forest for cattle raising.
It shows that increases in howler monkey 'travel time' the amount of time needed to find requisite nourishment are leading to increases in levels of stress hormones called glucocorticoids.
These hormones are not only indicators of stress, but are also known to relate to diminished reproductive success and lower survival rates.
Researchers believe the study could serve as a model for behavioural change and resulting health implications more generally in primates living in habitats disturbed by human activities, such as deforestation.
"Howlers are arboreal primates, that is to say they spend their wholes lives in the trees", said Dr Jacob Dunn from Cambridge's Department of Biological Anthropology, who carried out the research.
"As forests are fragmented, the howlers become cut off, isolated on forest 'islands' that increasingly lack the fruit which provide an important component of their natural diet. This has led to the monkeys expending ever more time and effort foraging for food, often increasing leaf consumption when their search is, quite literally, fruitless."
Fruit occurs in natural cycles, and the monkeys will naturally revert to 'fallback' foods, including leaves, when fruit is scarce. But as habitats shrink, and fruit is harder to find, leaves from second-choice plants, such as lianas, have increased in the Mexican howlers' diet.
While leaves may sound like a plentiful resource in a rainforest, many leaves are difficult to digest and can be filled with toxins - a natural defence mechanism in most trees and plants - so the monkeys are actually forced to spend more time seeking out the right foliage to eat, such as new shoots which are generally less toxic.
"The traditional view was that the leaves exploited by howler monkeys were an abundant food source - but this is not the case," said Dunn.
"The monkeys rely much more heavily on fruit than previously believed, and when turning to foliage for food - as they are increasingly forced to do they have to be highly selective in the leaves they consume, visiting lots of different trees. This leads to the increased 'travel time' and consequent high levels of stress we are seeing in these primates as their habitats disintegrate."
As trying to catch the howlers to examine them would in itself be highly stressful for the animal, the best way of evaluating stress levels in wild primates is by analysing their faeces for glucocorticoid stress hormones, which are general to all vertebrates.
Through statistical modelling, the researchers were able to determine that it is the 'travel time' - rather than the increased foliage intake - causing high levels of stress.
"Monkeys in disturbed habitats suffering high levels of stress is in itself unsurprising perhaps, but now we think we know why, the root cause from the primates perspective. Our results also highlight the importance of preserving and planting fruit trees - particularly those species such as figs that can produce fruit during periods of general fruit scarcity - for the conservation of howler monkeys said Dr Jurgi Cristbal-Azkarate, also from Cambridge, who led the research in collaboration with Dr Joaquim Vea from the University of Barcelona.
The authors say that further studies are required to fully understand the significance of increases in stress in howler monkeys living in disturbed habitats. "Determining the full relevance of our results for the conservation of primates living in forest fragments will require long-term studies of stress hormones and survival", said Dunn.
###
[ | E-mail | Share ]
?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Contact: Fred Lewsey fred.lewsey@admin.cam.ac.uk 07-885-798-680 University of Cambridge
Endangered Mexican howler monkeys are consuming more leaves and less fruit as a result of habitat disturbance by humans, which is forcing them to invest much more time foraging for sustenance and leading to increased 'stress' levels, as detected through hormone analysis.
The research, published today in the International Journal of Primatology, took place in the tropical rainforests of the Mexican state of Veracruz, which are being deforested and fragmented by human activity - primarily the clearing of forest for cattle raising.
It shows that increases in howler monkey 'travel time' the amount of time needed to find requisite nourishment are leading to increases in levels of stress hormones called glucocorticoids.
These hormones are not only indicators of stress, but are also known to relate to diminished reproductive success and lower survival rates.
Researchers believe the study could serve as a model for behavioural change and resulting health implications more generally in primates living in habitats disturbed by human activities, such as deforestation.
"Howlers are arboreal primates, that is to say they spend their wholes lives in the trees", said Dr Jacob Dunn from Cambridge's Department of Biological Anthropology, who carried out the research.
"As forests are fragmented, the howlers become cut off, isolated on forest 'islands' that increasingly lack the fruit which provide an important component of their natural diet. This has led to the monkeys expending ever more time and effort foraging for food, often increasing leaf consumption when their search is, quite literally, fruitless."
Fruit occurs in natural cycles, and the monkeys will naturally revert to 'fallback' foods, including leaves, when fruit is scarce. But as habitats shrink, and fruit is harder to find, leaves from second-choice plants, such as lianas, have increased in the Mexican howlers' diet.
While leaves may sound like a plentiful resource in a rainforest, many leaves are difficult to digest and can be filled with toxins - a natural defence mechanism in most trees and plants - so the monkeys are actually forced to spend more time seeking out the right foliage to eat, such as new shoots which are generally less toxic.
"The traditional view was that the leaves exploited by howler monkeys were an abundant food source - but this is not the case," said Dunn.
"The monkeys rely much more heavily on fruit than previously believed, and when turning to foliage for food - as they are increasingly forced to do they have to be highly selective in the leaves they consume, visiting lots of different trees. This leads to the increased 'travel time' and consequent high levels of stress we are seeing in these primates as their habitats disintegrate."
As trying to catch the howlers to examine them would in itself be highly stressful for the animal, the best way of evaluating stress levels in wild primates is by analysing their faeces for glucocorticoid stress hormones, which are general to all vertebrates.
Through statistical modelling, the researchers were able to determine that it is the 'travel time' - rather than the increased foliage intake - causing high levels of stress.
"Monkeys in disturbed habitats suffering high levels of stress is in itself unsurprising perhaps, but now we think we know why, the root cause from the primates perspective. Our results also highlight the importance of preserving and planting fruit trees - particularly those species such as figs that can produce fruit during periods of general fruit scarcity - for the conservation of howler monkeys said Dr Jurgi Cristbal-Azkarate, also from Cambridge, who led the research in collaboration with Dr Joaquim Vea from the University of Barcelona.
The authors say that further studies are required to fully understand the significance of increases in stress in howler monkeys living in disturbed habitats. "Determining the full relevance of our results for the conservation of primates living in forest fragments will require long-term studies of stress hormones and survival", said Dunn.
###
[ | E-mail | Share ]
?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Men who consume about two cups of coffee a day, or the equivalent amount of caffeine, are significantly more likely to have urinary incontinence or a ?leaky bladder? than men who drink less or none at all, according to new research from the US.
Senior author Alayne D. Markland, a professor at the University of Alabama at Birmingham, and colleagues, report their findings in a paper published online 2 January in The Journal of Urology.
In their background information they note while several studies have already established a link between caffeine intake and leaky bladder in women, the evidence for such a link in men is limited.
For their study, the researchers used national survey results from NHANES 2005-06 and 2007-08. This gave them data on over 5,000 American men aged 20 and over, with complete data available on nearly 4,000 of them.
The survey had collected information about food and drink intake which allowed the researchers to work out the men?s caffeine consumption, water intake, and the total moisture content of their diet.
The survey data also included Incontinence Severity Index scores, for which a value of 3 and above is rated moderate to urinary incontinence (UI). Moderate to severe UI is more than a few drops of urine leakage in a month.
After adjusting for other potential influencers, the researchers found the men who consumed the most caffeine were more likely to have a leaky bladder than those who consumed the least or none at all.
Their analysis shows men who consumed 234 or more mg per day of caffeine were 72% more likely to have moderate to severe UI than men who consumed the least or none at all.
Men with a daily caffeine intake of 392 mg per day were more than twice as likely to have leaky bladder problems.
In contrast, men?s total water intake was not linked to their risk for moderate to severe UI.
The researchers conclude:
?Caffeine consumption equivalent to approximately 2 cups of coffee per day (250mg) is significantly associated with moderate-severe UI in US men.?
They call for further studies to look into this link.
![[ Back to EurekAlert! ]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_vh5BMReQkm26rXdY0EopeN3RsXvNxwjE1jNGEWP1L9F9ArAGQdBmVlbeaOhd6JJGFZ-ZJtN423_ZTXdPUIfQ5Jce45VwsvJ4dz3afj0rk=s0-d){kind=small}
Public release date: 21-Jan-2013
Share ] 