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Thị Trấn Nho Quan, Vietnam

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Site: http://news.yahoo.com/science/

A pygmy slow loris (Nycticebus pygmaeus) in its natural habitat. The picture was taken in the Cuc Phuong National Park in Vietnam. More Hibernation is well-documented in a number of animal species, and is common across the mammal family tree. In primates, however, it's almost unheard of. Until recently, the only primates known to hibernate were Madagascar lemurs. But scientists have found another primate that settles down for a seasonal snooze: the pygmy slow loris, native to Vietnam. Researchers conducted the first-ever study of hibernation in pygmy slow lorises (Nycticebus pygmaeus), working with six adult animals at Vietnam's Endangered Primate Rescue Center. The researchers were looking for evidence such as reduced body temperature for extended periods of time, occurring in otherwise healthy animals. They built nesting boxes to mimic the tree holes that the lorises typically use for hibernating, and implanted the lorises with devices that logged their temperatures every 6 minutes for nearly a year. During the cool, dry winter months, from late October until early April, the lorises exhibited behavior and physical responses consistent with animals that are known hibernators. They would repeatedly retreat to their nesting boxes and lapse into periods of inactivity that lasted up to 63 consecutive hours at a time, the researchers said. While in hibernation, their temperatures would dip to about 52 degrees Fahrenheit (11 degrees Celsius). [In Photos: Cute New Slow Loris Species] The animals' bodies would also be stiff to the touch, said the study's corresponding author, Thomas Ruf, a physiologist with the University of Veterinary Medicine in Vienna. Ruf told Live Science that he had suspected for some time that lorises hibernated, based on accounts dating back to the 1980s. Those reports described lorises curled up in trees, where they remained inactive for days. But without monitoring the animals over time, it was impossible to tell whether this was a sign of hibernation or of illness, Ruf added. The data gathered by Ruf and his colleagues provided the first evidence that the lorises entered a state of inactivity and reduced metabolic rate in response to seasonal changes, the new study reported. Hibernation is an effective survival strategy for animals living in parts of the world where changing seasons mean that food is less available for parts of the year. Pygmy slow lorises eat fruit and insects, and when winter rolls around, the insects become scarce. "That's why we think they hibernate — they have to save energy somehow," Ruf said. Another benefit of hibernation is that the drop in body temperature means that animals' natural body odors are reduced, making the creatures harder for predators to detect, Ruf said. He recalled an experiment from decades ago that "you couldn't do these days," in which hibernating mice were placed in a room with hungry weasels. Because the mice were cold, motionless and stiff, the weasels weren't interested and left the potential prey alone. Likewise, lorises hibernating in trees would be easy prey for snakes, but a cold, stiff, loris doesn't have much appeal to predators looking for a warm, lively dinner. "Hibernation is a very safe time for animals," Ruf told Live Science. "They have a very high survival probability." Small wonder, then, that so many animals hibernate. In mammals, hibernation appears in 11 different orders, which suggests the behavior originated far back in the ancestral time line of mammals. "It's unlikely that it evolved independently among so many genetic branches, " Ruf said. "So it must be really old." It's possible that more hibernating species are yet to be discovered, even in the primate lineage, where hibernation is considered rare. Hibernating lemurs and the pygmy slow loris all belong to the same suborder, Strepsirrhini, and more species in that grouping could be hibernators, too, the researchers said. "I suspect there are more primates that hibernate," Ruf added. "Now we have to go and look." The findings were published online Dec. 3 in the journal Scientific Reports. Follow Mindy Weisberger on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science. Copyright 2015 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.


Pan W.,Hong Kong Baptist University | Liu K.,Hong Kong Baptist University | Guan Y.,Hong Kong Baptist University | Tan G.T.,University of Hawaii at Hilo | And 6 more authors.
Journal of Natural Products | Year: 2014

A new lignan, vitexkarinol (1), as well as a known lignan, neopaulownin (2), a known chalcone, 3-(4-hydroxyphenyl)-1-(2,4,6-trimethoxyphenyl)-2-propen- 1-one (3), two known dehydroflavones, tsugafolin (4) and alpinetin (5), two known dipeptides, aurantiamide and aurantiamide acetate, a known sesquiterpene, vemopolyanthofuran, and five known carotenoid metabolites, vomifoliol, dihydrovomifoliol, dehydrovomifoliol, loliolide, and isololiolide, were isolated from the leaves and twigs of Vitex leptobotrys through bioassay-guided fractionation. The chalcone (3) was found to inhibit HIV-1 replication by 77% at 15.9 μM, and the two dehydroflavones (4 and 5) showed weak anti-HIV activity with IC50 values of 118 and 130 μM, respectively, while being devoid of cytotoxicity at 150 μM. A chlorophyll-enriched fraction of V. leptobotrys, containing pheophorbide a, was found to inhibit the replication of HIV-1 by 80% at a concentration of 10 μg/mL. Compounds 1 and 3 were further selected to be evaluated against 21 viral targets available at NIAID (National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA). © 2014 The American Chemical Society and American Society of Pharmacognosy. Source


Truong B.N.,Vietnam Academy of Science and Technology | Pham V.C.,Vietnam Academy of Science and Technology | Mai H.D.T.,Vietnam Academy of Science and Technology | Nguyen V.H.,Vietnam Academy of Science and Technology | And 7 more authors.
Phytochemistry Letters | Year: 2011

Two new glucosides, 3-methoxy-4-hydroxyphenylpropane-7,8-(6′-benzoyl- 2′,1′-O-β-glucopyranosyl)-7,8,9-trio (1), and 2-hydroxyphenyl-4-caffeoyl-β-d-glucoside (2), together with seven known compounds were isolated from the stem bark of Xylosma longifolia (Flacourtiaceae). The structures of the isolates were established on the basis of their spectral data, including mass spectrometry and 2D-NMR. The compound 8-hydroxy-6-methoxy-pentylisocoumarin (3) exhibited an MIC value of 40.5 μg/mL against M. tuberculosis. © 2011 Phytochemical Society of Europe. Source


Truong N.B.,Vietnam Academy of Science and Technology | Pham C.V.,Vietnam Academy of Science and Technology | Doan H.T.M.,Vietnam Academy of Science and Technology | Nguyen H.V.,Vietnam Academy of Science and Technology | And 7 more authors.
Journal of Natural Products | Year: 2011

Three new triterpenoids, bonianic acids A (1) and B (2) and 3-O-acetyluncaric acid (3), were isolated from the leaves and twigs of Radermachera boniana, together with six known compounds, ursolic acid (4), oleanolic acid (5), 3-epi-oleanolic acid (6), 3α-O-acetyl-α- boswellic acid (7), ergosterol peroxide (8), and β-sitostenone (9). Ergosterol peroxide (8) and bonianic acids A (1) and B (2) exhibited significant activity against Mycobacterium tuberculosis H37Rv strain. (Chemical Equation Presented). © 2011 The American Chemical Society and American Society of Pharmacognosy. Source


Guan Y.,Hong Kong Baptist University | Guan Y.,Institute of Integrated Bioinfomedicine and Translational Science | Wang D.,Hong Kong Baptist University | Wang D.,Institute of Integrated Bioinfomedicine and Translational Science | And 8 more authors.
American Journal of Chinese Medicine | Year: 2016

Litsea verticillata Hance (Lauraceae), a Chinese medicine used to treat swelling caused by injury or by snake bites, was the first plant identified by our National Institutes of Health (NIH)-funded International Cooperative Biodiversity Group (ICBG) project to exhibit anti-HIV activities. From this plant, we discovered a class of 8 novel litseane compounds, prototypic sesquite rpenes, all of which demonstrated anti-HIV activities. In subsequent studies, 26 additional compounds of different structural types were identified. During our continuing investigation of this plant species, we identified two new litseanes, litseaverticillols L and M, and a new sesquiterpene butenolide, litseasesquibutenolide. Litseaverticillols L and M were found to inhibit HIV-1 replication, with an IC50 value of 49.6μM. To further determine the antiviral properties of this plant, several relatively abundant isolates, including a litseane compound, two eudesmane sesquiterpenes and three lignans, were evaluated against an additional 21 viral targets. Lignans 8 and 9 were shown to be active against the Epstein-Barr Virus (EBV), with EC50 values of 22.0μM (SI=3.8) and 16.2μM (SI>6.2), respectively. Since many antiviral compounds have been discovered in L. verticillata, we further prepared 38 plant extracts made from the different plant parts of 9 additional Litsea species. These extracts were evaluated for their anti-HIV and cytotoxic activities, and four of the extracts, which ranged across three different species, displayed 97-100% inhibitory effects against HIV replication without showing cytotoxicity to a panel of human cell lines at a concentration of 20μg/mL. © 2016 World Scientific Publishing Company. Source

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