Mostrando entradas con la etiqueta Organismos. Mostrar todas las entradas
Mostrando entradas con la etiqueta Organismos. Mostrar todas las entradas

viernes, 7 de febrero de 2014

The world's 10 oldest living trees

There are colonies of clonal trees that have lived for tens of thousands of years, but there's something majestic about a single tree able to stand on its own for millennia. These ancient trees have bore witness to the rise and fall of civilizations, survived changing climates, and even persevered through the fervent development of human industry. They are a testament to the long view that Mother Nature takes in tending the Earth. With that in mind, consider the world's 10 oldest living trees.

Photo:zest-pk/Flickr

Methuselah
At 4,841 years old, this ancient bristlecone pine is the oldest known non-clonal organism on Earth. Located in the White Mountains of California, in Inyo National Forest, Methuselah's exact location is kept a close secret in order to protect it from the public. (An older specimen named Prometheus, which was about 4,900 years old, was cut down by a researcher in 1964 with the U.S. Forest Service's permission.) Today you can visit the grove where Methuselah hides, but you'll have to guess at which tree it is. Could this one be it?
Photo:Rick Goldwasser/Flickr



Sarv-e Abarqu
Sarv-e Abarqu, also called the "Zoroastrian Sarv," is a cypress tree in Yazd province, Iran. The tree is estimated to be at least 4,000 years old and, having lived through the dawn of human civilization not far away, it is considered an Iranian national monument. Many have noted that Sarv-e Abarqu is most likely the oldest living thing in Asia.

Photo:iranian.com


Llangernyw Yew

This incredible yew resides in a small churchyard of St. Dygain's Church in Llangernyw village, north Wales. About 4,000 years old, the Llangernyw Yew was planted sometime in the prehistoric Bronze Age — and it's still growing! In 2002, in celebration of the golden jubilee of Queen Elizabeth II, the tree was designated as one of 50 Great British trees by the Tree Council.
Photo:Wiki Commons


Alerce
The Alerce is a common name for Fitzroya cupressoides, a towering tree species native to the Andes mountains. There's almost no telling how old these trees can get, since most of the larger specimens were heavily logged in the 19th and 20th centuries. Many botanists believe they are the second-longest living trees on Earth aside from the bristlecone pine of North America. To date, the oldest known living specimen is 3,640 years old.
Photo:Wiki Commons/GNU


The Senator

The Senator, located in Florida, is the largest bald cypress tree in the United States, and it is widely considered the oldest of its species known to exist. It is likely the largest U.S. tree of any species east of the Mississippi River. Estimated to be around 3,500 years old, the Senator was used as a landmark for the Seminole indians and other native tribes. The Senator's size is particularly impressive because it has endured many hurricanes, including one in 1925 which reduced its height by 40 feet.

The tree gets its name from from Sen. M.O. Overstreet, who donated the tree and surrounding land in 1927.

Update 1.17.12: It is with a heavy heart that we report that 'The Senator' has burned to the ground
Árbol de 3500 años se incendia y colapsa por imprudencia de adicta a drogas
Photo:Ashley Schmidt/Wiki Commons

Patriarca da Floresta

This tree, an example of the species Cariniana legalis named Patriarca da Floresta in Brazil, is estimated to be about 3,000 years old, making it the oldest non-conifer in Brazil. The tree is believed to be sacred, but its species is widely threatened due to forest clearing in Brazil, Colombia and Venezuela.
Photo:bocaberta.org


Olive Tree of Vouves

This ancient olive tree is located on the Greek island of Crete and is one of seven olive trees in the Mediterranean believed to be at least 2,000 to 3,000 years old. Although its exact age cannot be verified, the Olive Tree of Vouves might be the oldest among them, estimated at over 3,000 years old. It still produces olives, and they are highly prized. Olive trees are hardy and drought-, disease- and fire-resistant — part of the reason for their longevity and their widespread use in the region.

 
Photo: Carmel Jane Doak/Panorami


Jōmon Sugi

Jōmon Sugi, located in Yakushima, Japan, is the oldest and largest cryptomeria tree on the island, and is one of many reasons why the island was named a UNESCO World Heritage Site. The tree dates to at least 2,000 years old, but some experts believe it could be older than 5,000 years old. Under that theory, it's possible that Jōmon Sugi is the oldest tree in the world — even older than Methuselah. Regardless of the numbers, it's a tree that deserves mention here.
  
Photo:Wiki Commons/GNU


Chestnut Tree of One Hundred Horses

This tree, located on Mount Etna in Sicily, is the largest and oldest known chestnut tree in the world. Believed to be between 2,000 and 4,000 years old, this tree's age is particularly impressive because Mount Etna is one of the most active volcanoes in the world. The tree sits only 5 miles from Etna's crater. The tree's name originated from a legend in which a company of 100 knights were caught in a severe thunderstorm. According to the legend, all of them were able to take shelter under the massive tree. It is listed by Guinness World Records as having the "greatest tree girth ever," at 190 feet in circumference.
  
Photo:Wiki Commons/GNU


General Sherman
Believed to be around 2,500 years old, General Sherman is the mightiest giant sequoia still standing. The volume of its trunk alone makes it the largest non-clonal tree by volume in the world, even though its largest branch broke off in 2006, smashing part of its enclosing fence and cratering the pavement of the surrounding walkway. Perhaps this was a sign that General Sherman could not be caged in? Sherman can be found in Sequoia National Park in California, where five of the 10 largest trees in the world exist.
 
Photo:Wiki Commons

ORIGINAL:
Mother Nature Network
Apr 07, 2010

miércoles, 8 de enero de 2014

A unique covalent bond in basement membrane is a primordial innovation for tissue evolution

Significance
The evolution of multicellular animals from single-celled ancestors was one of the most significant transitions of life on earth. The emergence of larger, more complex animals able to resist predation and colonize new environments was enabled, in part, by a collagen scaffold, which anchors cells together to form tissues and organs. Here, we show that a unique chemical bond, a link between sulfur and nitrogen atoms called a sulfilimine bond, arose over 500 Mya, binding this scaffold together and enabling tissues to withstand mechanical forces. Peroxidasin forms the bond by generating hypohalous acids as strong oxidants, a form of bleach, which normally function as antimicrobial agents. These understandings may lead to approaches for targeting tumors and treatment of other diseases.
Fig. 1.  The sulfilimine bond stabilizes collagen IV scaffolds by the cross-linking of triple helical building block protomers.
(A) The sulfilimine bond cross-links Met93 and Hyl211 at the interface between the trimeric NC1 domains of two adjoining protomers, forming a globular hexamer structure.
(B) Dimeric subunits reflect the presence of the sulfilimine bond in human collagen IV by immunoblot (JK2 Ab) and protein stain.
(C) MS analysis of tryptic peptides derived from dimeric subunits verified the presence of the bond by a mass difference of 2.0299 between theoretical mass of uncross-linked and observed mass of cross-linked peptides and subsequent multistep CID fragmentation (MS2/MS3) analyses.

Fig. 2. Multiple sequence alignment of collagen IV NC1 domains encompassing Met93 and Hyl211 amino acid residues and Pxdn among 11 metazoan and 1 protozoan phyla.
(A) Met93 and Lys/Hyl211 (yellow) are conserved in all eumetazoans, except for the cnidarian H. magnipapillata, and they are absent in the phyla of Placozoa and Porifera and the protozoan phylum Choanozoa. All sequences belong to the collagen IV α1-like subfamily of chains, except for Drosophila (viking) and Ascaris (α2 chain).
(B) Schematic representations of Pxdn. Pxdn sequence was incomplete on both ends for Mytilus, Clytia, Trichoplax, and Monosiga and short on one end for Saccoglossus, which is indicated here by a shortened schematic representation. Sequence data were gathered from *National Center for Biotechnology Information Reference Sequence, †gathered from whole-genome shotgun/transcriptome shotgun assembly, §generated by RNA-Seq analysis of animal tissues, or ¶assembled from cDNA libraries. All National Center for Biotechnology Information GenBank accession numbers are listed in Table S1.

Fig. 3. NC1 hexamers were excised from animal basement membranes and analyzed by SDS/PAGE as shown in Fig. 1 A and B. The dimeric subunits, which indicate the presence of the bond, were found in nine major eumetazoan phyla. Among eight cnidarians investigated, only Hydra NC1 lacked dimeric subunits. All NC1s were immunoblotted against the rat monoclonal antibody, JK2, except for C. elegans (rabbit polyclonal; NW-154) and Drosophila (mouse monoclonal; 6G7). Black outlines indicate the locations of cropping for blot images. 

Fig. 4. Expression of collagen IV and Pxdn during development in zebrafish and morpholino (MO) knockdown of peroxidasin in zebrafish embryos. (A) Pxdn and collagen IV expression during zebrafish embryonic development. Real-time qPCR studies were conducted to examine expression levels of Pxdn, collagen4α1, and collagen4α2. *Student t test P value < 0.03 compared with expression at 1,000 cells. Error bars = SEM. Blue, pxdn; red, col4a; black, col4a2. (B) Control and (C) Pxdn MO groups. MO-injected embryos displayed (D) general severe defects that include cardiac edema, smaller eyes, and gross trunk patterning defects (4/45), (E) partial curved trunk (21/45), or (F) normal development (20/45). (G) SDS/PAGE analysis of Pxdn MO embryonic phenotypes at 24 hpf by Western blot. Collagenase digests were normalized for total protein load by protein stain with SYPRO-Ruby (Fig. S8).


Abstract
Basement membrane, a specialized ECM that underlies polarized epithelium of eumetazoans, provides signaling cues that regulate cell behavior and function in tissue genesis and homeostasis. A collagen IV scaffold, a major component, is essential for tissues and dysfunctional in several diseases. Studies of bovine and Drosophila tissues reveal that the scaffold is stabilized by sulfilimine chemical bonds (S = N) that covalently cross-link methionine and hydroxylysine residues at the interface of adjoining triple helical protomers. Peroxidasin, a heme peroxidase embedded in the basement membrane, produces hypohalous acid intermediates that oxidize methionine, forming the sulfilimine cross-link. We explored whether the sulfilimine cross-link is a fundamental requirement in the genesis and evolution of epithelial tissues by determining its occurrence and evolutionary origin in Eumetazoa and its essentiality in zebrafish development; 31 species, spanning 11 major phyla, were investigated for the occurrence of the sulfilimine cross-link by electrophoresis, MS, and multiple sequence alignment of de novo transcriptome and available genomic data for collagen IV and peroxidasin. The results show that the cross-link is conserved throughout Eumetazoa and arose at the divergence of Porifera and Cnidaria over 500 Mya. Also, peroxidasin, the enzyme that forms the bond, is evolutionarily conserved throughout Metazoa. Morpholino knockdown of peroxidasin in zebrafish revealed that the cross-link is essential for organogenesis. Collectively, our findings establish that the triad—a collagen IV scaffold with sulfilimine cross-links, peroxidasin, and hypohalous acids—is a primordial innovation of the ECM essential for organogenesis and tissue evolution.

Footnotes
1A.L.F., R.M.V., and S.V.C. contributed equally to this work.
2A list of The Aspirnaut coauthors can be found in Table S2. Aspirnaut is a K--20 Science, Technology, Engineering, and Math (STEM) pipeline program for diversity that partners the experiential and content expertise of Vanderbilt University with rural kindergarten through 12th grade schools and diverse high school, undergraduate, and graduate students.
3To whom correspondence should be addressed. E-mail: billy.hudson@vanderbilt.edu.

Author contributions: R.M.V., S.V.C., V.K.P., V.P.Y., M.T.I., J.K.H., and B.G.H. designed research; A.L.F., S.V.C., G.B., V.P.Y., C.L.S., K.L.R., W.H.M., T.A.C., D.-B.B., R.E.S., and T.A. performed research; G.B. contributed new reagents/analytic tools; A.L.F., R.M.V., S.V.C., V.K.P., V.P.Y., D.-B.B., and R.E.S. analyzed data; and A.L.F. and B.G.H. wrote the paper.

The authors declare no conflict of interest.

*This Direct Submission article had a prearranged editor.

Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. GAMX01000001, GAMX01000002, GAND01000001, GAND01000002, GANB01000001, GANB01000002,GAMY01000001, GAMY01000002, GANA01000001, GANA01000002, GAMZ01000002, and GANC01000002).

This article contains supporting information online at 

Freely available online through the PNAS open access option. (Full Text)

ORIGINAL: PNAS
The Aspirnautsb,2,

Edited* by Mina J. Bissell, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, and approved November 22, 2013 (received for review September 30, 2013)