Structural Features and Anti-Complement Activity of an
Acidic Polysaccharide from Forsythia suspensa
The complement system can be
activated by three separate pathways including the classical pathway (CP),
alternative pathway (AP) and lectin pathway (LP) to mobilize defence mechanisms
against the invasion of foreign materials such as bacteria and viruses. All
three pathways comprise different components and are activated in different
fashions but use a common terminal pathway. The CP is activated when C1q
interacts with its ligands such as immune-complexes (ICs), the LP is activated
when MBL or ficolins binds to certain carbohydrates and the AP can be activated
by spontaneous C3 hydrolysis or via properdin, thereby generating C3 (H2O)
which can bind factor B (fB). Activation of each of these pathways generates
C3- convertases resulting in activation of the common terminal pathway and
generating several effector processes, such as chemotaxis by C3a and C5a,
opsonization by C3b, and lysis by the membrane attack complex.
Nasa's Curiosity rover begins exploring new Mars
destinations
Nasa's Curiosity Mars rover is
driving towards new uphill destinations to further study ancient, water-rich
environments and potential for life on the red planet. The destinations include
a ridge capped with material rich in the iron-oxide mineral hematite, about
two-and-a-half kilometres from its current location, and an exposure of
clay-rich bedrock beyond that.
These are key exploration sites on lower Mount Sharp, which is a layered mound where the Curiosity rover is studying evidence of ancient, water-rich environments that contrast with the harsh, dry conditions on the surface of Mars today. "We continue to reach higher and younger layers on Mount Sharp," said Curiosity Project Scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory in the US. Hundreds of photos Curiosity took in recent weeks amid a cluster of mesas and buttes of diverse shapes are fresh highlights among the more than 180,000 images the rover has taken since landing on Mars in August 2012. Newly available vistas include the rover's self-portrait from the colour camera at the end of its arm and a scenic panorama from the colour camera at the top of the mast.
"Bidding good-bye to 'Murray Buttes,' Curiosity's assignment is the ongoing study of ancient habitability and the potential for life," said Curiosity Programme Scientist Michael Meyer at NASA Headquarters, Washington.
"This mission, as it explores the succession of rock layers, is reading the 'pages' of Martian history - changing our understanding of Mars and how the planet has evolved," Meyer said. The latest drill site - the 14th for Curiosity - is in a geological layer about 180 meters thick, called the Murray formation. Curiosity has climbed nearly half of this formation's thickness so far and found it consists primarily of mudstone, formed from mud that accumulated at the bottom of ancient lakes. The findings indicate that the lake environment was enduring, not fleeting. For roughly the first half of the new two-year extended mission, the rover team anticipates investigating the upper half of the Murray formation.
These are key exploration sites on lower Mount Sharp, which is a layered mound where the Curiosity rover is studying evidence of ancient, water-rich environments that contrast with the harsh, dry conditions on the surface of Mars today. "We continue to reach higher and younger layers on Mount Sharp," said Curiosity Project Scientist Ashwin Vasavada, of NASA's Jet Propulsion Laboratory in the US. Hundreds of photos Curiosity took in recent weeks amid a cluster of mesas and buttes of diverse shapes are fresh highlights among the more than 180,000 images the rover has taken since landing on Mars in August 2012. Newly available vistas include the rover's self-portrait from the colour camera at the end of its arm and a scenic panorama from the colour camera at the top of the mast.
"Bidding good-bye to 'Murray Buttes,' Curiosity's assignment is the ongoing study of ancient habitability and the potential for life," said Curiosity Programme Scientist Michael Meyer at NASA Headquarters, Washington.
"This mission, as it explores the succession of rock layers, is reading the 'pages' of Martian history - changing our understanding of Mars and how the planet has evolved," Meyer said. The latest drill site - the 14th for Curiosity - is in a geological layer about 180 meters thick, called the Murray formation. Curiosity has climbed nearly half of this formation's thickness so far and found it consists primarily of mudstone, formed from mud that accumulated at the bottom of ancient lakes. The findings indicate that the lake environment was enduring, not fleeting. For roughly the first half of the new two-year extended mission, the rover team anticipates investigating the upper half of the Murray formation.
By
Chandrasekharan
III B. Sc.,
Department of Biochemistry
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