A number of
recent papers have expanded our knowledge of the King Cobra, or Hamadryad, (Ophiophagus hannah), here a few that
have appeared during 2010.
Bashir, et al.
(2010) reports the sighting of the King Cobra from Yuksam village
(27022’12.5’’N and 88013’27.0’’E). The village borders the Khangchendzonga
Biosphere Reserve in the West District of Sikkim, India. The snake was observed
in a drain adjoining human settlement (at an altitude of 1820 m) on 6 December
2009 at 0805 hr. The snake was estimated to be about 3−3.5 m. A few days later,
the snake was seen basking on a rock near bamboo thickets adjoining the lake.
There are two highlights: the new altitude record of 1840 m. for the northeast
portion of the range; and, the fact that the snake was using the transitional
forest between subtropical broadleaved evergreen forest and temperate forests.
The species has not been previously reported from this Sikkim environment.
Previously it was reported from Gangtok at 1700m in 1923 and was believed to be
limited to the tropical forests of Sikkim Himalaya which are found below 1250
m. The highest known altitude record for the Hamadryad in northeastern India
was 1700m at Khonoma, Nagaland (Das et al. 2008).
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Superimposition of haditoxin subunit A (blue) with erabutoxin-a (magenta), erabutoxin-b (cyan),
and toxin-α (green), which highlights haditoxin's three-finger protein
fold and its resemblance to other short-chain α-neurotoxins.
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Chen and Lai
(2010) from the Guangzhou University of Chinese Medicine sequenced the complete
mitochondrial genome of King Cobra (GenBank accession number: EU_921899) by Ex
Taq-PCR, TA-cloning and primer-walking methods. The cobra’s genome is similar
to other vertebrate. It is 17 267 bp in length and encodes 38 genes (including
13 protein-coding, 2 ribosomal RNA and 23 transfer RNA genes) and it contains two,
long, non-coding regions. This data demonstrated that Elapidae is more closely
related to Colubridae (=Colubroidae) than Viperidae, supporting previous work.
Zedoary
(Curcuma zedoaria, family Zingiberaceae)
is a plant native to South and Southeast Asia and it was introduced into Europe
sometime in the sixth century, and while it is used as a spice it is rare,
having been replaced by ginger. It is commonly used in the northeastern Thailand
as a snakebite remedy. Lattmann, et al. (2010) isolated the active compound
from the rhizome of C. zedoaroides, determined its structure and assessed
its antagonistic properties against King Cobra venom. The acetone extract from
the rhizomes of Curcuma rhizomes contained a C20 dialdehyde, as the
major component. The isolated curcuma dialdehyde was to be found active in both
in vitro and in vivo tests for antivenin activity against King Cobra
venom. Using isolated rat phrenic nerve-hemidiaphragm preparations, the
researchers found a significant antagonistic effect on the inhibition of
neuromuscular transmission and muscle contractions were inhibited by the venom,
and found they could reversed it with Curcuma dialdehyde in organ bath
preparations over a period of 2 hours. Mice injected with 0.75 mg/kg venom and the
dialdehyde had a significantly increased survival time. Injection of the Curcuma
dialdehyde 30 minutes before the subcutaneous injection of the venom resulted
in a 100% survival time after 2 h compared with 0% for the control group. Thus
the in vitro and in vivo evaluation confirmed the medicinal use
of Zedoary against King Cobra
venom.
Roy et al.
(2010) have described haditoxin, a novel peptide from the venom of Ophiophagus. They provide a detailed
structural and functional characterization of this unusual neurotoxin. Using a
1.5 Å crystal structure, they found haditoxin exists as a homodimer, similar to
the κ-neurotoxin family, but the monomeric subunits of haditoxin, consist of a
three-finger protein fold closely resembling a short-chain α-neurotoxins,
unlike κ-neurotoxin monomers, which resemble long-chain α-neurotoxins. While
haditoxin could antagonize several classes of nicotinic acetylcholine receptors
in neurons and muscle, its greatest potency was against receptors, which neiher
recognized by short-chain α-neurotoxins or κ-neurotoxins. Thus haditoxin might
have many future uses in developing molecular probes and therapeutic agents.
Literature
Bashir,
T., K. Poudyal, T. Bhattacharya, S. Sathyakumar & J.B. Subba, 2010.
Sighting of King Cobra Ophiophagus hannah in Sikkim, India: a new
altitude record for the northeast. Journal of Threatened Taxa 2(6):
990-991.
Chen N. and X. P. Lai. 2010. [Sequencing and
analysis of the complete mitochondrial genome of the King Cobra, Ophiophagus hannah (Serpents: Elapidae)]
[Article in Chinese]. Yi Chan
32(7):719-25.
Lattmann, E., J. Sattayasai,, N.
Sattayasai, A. Staaf, S. Phimmasone, C. H. Schwalbe, and A. Chaveerach. 2010.
In-vitro and in-vivo antivenin activity of 2-[2-(5,5,8a-trimethyl-2-methylene-decahydro-naphthalen-1-yl)-ethylidene]-succinaldehyde
against Ophiophagus hannah venom. Journal
of Pharmacy and Pharmacology, 62:257–262. doi: 10.1211/jpp.62.02.0014
Roy,
A., X. Zhou, M. Z. Chong, D. D'hoedt, C. S. Foo, N. Rajagopalan, S. Nirthanan,
D. Bertrand, J. Sivaraman, and R. Manjunatha Kini. 2010. Structural and
Functional Characterization of a Novel Homodimeric Three-finger Neurotoxin from
the Venom of Ophiophagus hannah (King Cobra) Journal of Biological
Chemistry 285:
8302-8315.