Biology Reference
In-Depth Information
Kornalik and Táborská, 1978; Sawai et al., 1985; Zotz et al., 1991). Thus, the majority
of well-documented medically important effects are due to procoagulant toxins func-
tioning as those often observed in some viperid and Australian elapid venoms. These
venoms have been previously reviewed (Mackessy, 2002; Weinstein and Kardong,
1994) and are considered further in Section 4.3.
Knowledge of the nature of constituent toxins present in these secretions began
to accumulate with the fractionation of venoms from
Malpolon monspessulanus
(Montpellier snake) and
Spalerosophis
spp. (diadem or camel snakes; approximately
five species) (Rosenberg et al., 1985). Much of the work on secretions and ven-
oms from these colubroids has been hampered by limited availability of secretions
and very low yields obtained by extraction. Rosenberg et al. (1985) addressed this
problem by recommending the use of parasympathomimetic agents, such as pilocar-
pine, while collecting the secretion using a capillary pipette. This technique has been
modified and used effectively in order to procure samples for more extensive pharma-
cological and biochemical/structural analyses (Fry et al., 2003; Hill and Mackessy,
1997, 2000; Pawlak et al., 2006, 2009).
Use of FPLC, HPLC, online mass spectroscopy, and other separation modalities facil-
itated the continuing analysis of several colubrid secretions/venoms, including that of the
ecologically important brown tree snake,
Boiga irregularis
(Broaders et al., 1999; Fry
et al., 2003; Hill and Mackessy, 2000; Mackessy et al., 2006; Pawlak et al., 2006, 2009;
Weinstein and Smith, 1993; Weinstein et al., 1991). Renewed attention to this under-
studied area resulted in studies of other colubrid species of regional medical importance
[e.g.,
Philodryas olfersii
(Lichtenstein's or green racer) in Brazil (Ribeiro et al., 1999)
and Argentina (Acosta de Pérez et al., 2003);
P. patagoniensis
(Patagonian racer) in
Argentina (Peichoto et al., 2005); and
Thamnodynastes stigilis
(northern coastal house
snake) in Venezuela (Lemoine et al., 2004a)]. Comprehensive reviews of colubrid secre-
tions and venoms and reported colubrid envenomations (Mackessy, 2002; Minton, 1990;
Warrell, 2004; Weinstein and Kardong, 1994) stimulated further investigations.
With the advent of proteomics and genomic arrays, the study of these secretions
and venoms has accelerated and advanced. Properties and/or partial primary sequences
of several saliva and venom/secretion components were reported by Hill and Mackessy
(2000). A complete sequence for a “three-finger-fold” postsynaptically active neuro-
toxin
1
(“colubritoxin”) isolated from secretion of the radiated rat snake [
Coelognathus
(
Elaphe
Fitzinger, 1833)
radiatus
; Utiger et al., 2005] was elucidated by Fry et al.
(2003). Lumsden et al. (2005) reported weak postsynaptic and prejunctional neurotoxic-
ity induced by a three-finger toxin (“boigatoxin A” isolated from Duvernoy's secretion
of the mangrove snake,
Boiga dendrophila
) in rat skeletal muscle and smooth muscle
(vas deferens), respectively. Avian and/or saurian-specific three-finger neurotoxins,
“denmotoxin” and “irditoxin,” were structurally and functionally characterized from
B. dendrophila
and
B. irregularis
secretions, respectively (Pawlak et al., 2006, 2009), con-
firming previous observations suggesting the presence of neurotoxins in their secretions
1
“Three-finger-fold” neurotoxins were previously classified as various types of short-chain or long-chain
postsynaptic neurotoxins. These were structurally grouped according to the numbers of amino acids and
disulfide bonds comprising a given characterized toxin.
