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Mad, Bad and Dangerous to Know: The Biochemistry, Ecology and Evolution of Slow Loris Venom

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Mad, Bad and Dangerous to Know: The Biochemistry, Ecology and Evolution of Slow Loris Venom

K Anne-Isola Nekaris et al. J Venom Anim Toxins Incl Trop Dis.

Abstract

Only seven types of mammals are known to be venomous, including slow lorises (Nycticebus spp.). Despite the evolutionary significance of this unique adaptation amongst Nycticebus, the structure and function of slow loris venom is only just beginning to be understood. Here we review what is known about the chemical structure of slow loris venom. Research on a handful of captive samples from three of eight slow loris species reveals that the protein within slow loris venom resembles the disulphide-bridged heterodimeric structure of Fel-d1, more commonly known as cat allergen. In a comparison of N. pygmaeus and N. coucang, 212 and 68 compounds were found, respectively. Venom is activated by combining the oil from the brachial arm gland with saliva, and can cause death in small mammals and anaphylactic shock and death in humans. We examine four hypotheses for the function of slow loris venom. The least evidence is found for the hypothesis that loris venom evolved to kill prey. Although the venom's primary function in nature seems to be as a defense against parasites and conspecifics, it may also serve to thwart olfactory-orientated predators. Combined with numerous other serpentine features of slow lorises, including extra vertebra in the spine leading to snake-like movement, serpentine aggressive vocalisations, a long dark dorsal stripe and the venom itself, we propose that venom may have evolved to mimic cobras (Naja sp.). During the Miocene when both slow lorises and cobras migrated throughout Southeast Asia, the evolution of venom may have been an adaptive strategy against predators used by slow lorises as a form of Müllerian mimicry with spectacled cobras.

Figures

Figure 1
Figure 1
The slow loris brachial gland (dark oblong area on the inside of the elbow region).
Figure 2
Figure 2
Slow lorises in defensive posture, whereby the arms are raised above the head to combine saliva with brachial gland exudate: N. menagensis, N. javanicus and N. coucang.
Figure 3
Figure 3
Comparison of pygmy and greater slow loris LC/MS profiles and 4 A and B sequence alignment.
Figure 4
Figure 4
NH2-terminal amino acid sequences of the pygmy loris α- and β-chains that make up the 18k major peptide of brachial gland exudate. (A) Comparison between the pygmy loris α-chain sequence and members from each clade of the α-chain superfamily: 1. secretoglobin (3288868); 2. mouse salivary androgen binding protein (19919338); 3. mouse putative protein 20948528; 4. loris brachial gland secretion; 5. domestic cat allergen; 6. human genome putative protein; 7. uteroglobin (6981694); and 8. lipophilin (5729909). Numbers refer to NCBI accession numbers. Homologous amino acids are highlighted in grey. (B) Comparison between the pygmy loris β-chain sequence and two members with similar β-chains. 1. domestic cat allergen (423192); 2. loris brachial gland secretion β-chain; and 3. mouse salivary protein (19353044).
Figure 5
Figure 5
Male wild Nycticebus javanicus, from Cipaganti near Garut, Java, during three successive captures in April 2012, November 2012 and February 2013, showing his appearance before receiving a severe conspecific bite wound, just afterwards, and 3 months afterwards.
Figure 6
Figure 6
Potential mimicry of spectacled cobras in Javan and Bengal slow lorises (1). Javan slow loris (2) Spectacled cobra (rear view) (3) Spectacled cobra (front view) (4) Bengal slow loris.

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References

    1. Harvey AL. In: Animal Toxins: State of the Art – Perspectives in Health and Biotechnology. de Lima ME, editor. Belo Horizonte: UFMG; 2009. Overview; pp. 19–22.
    1. Kita M, Nakamura Y, Okumura Y, Ohdachi SD, Oba Y, Yoshikuni M, Kido H, Uemura D. Blarina toxin, a mammalian lethal venom from the short-tailed shrew Blarina brevicauda: Isolation and characterization. Proc Natl Acad Sci U S A. 2004;101(20):7542–7547. doi: 10.1073/pnas.0402517101. - DOI - PMC - PubMed
    1. Ligabue-Braun R, Verli H, Carlini CR. Venomous mammals: a review. Toxicon. 2012;59(7–8):680–695. - PubMed
    1. Whittington CM, Papenfuss AT, Bansal P, Torres AM, Wong ES, Deakin JE, Graves T, Alsop A, Schatzkamer K, Kremitzki C, Ponting CP, Temple-Smith P, Warren WC, Kuchel PW, Belov K. Defensins and the convergent evolution of platypus and reptile venom genes. Genome Res. 2008;18(6):986–994. doi: 10.1101/gr.7149808. - DOI - PMC - PubMed
    1. Low DH, Sunagar K, Undheim EA, Ali SA, Alagon AC, Ruder T, Jackson TN, Pineda Gonzales G, King GF, Jones A, Antunes A, Fry BG. Dracula’s children: Molecular evolution of vampire bat venom. J Proteomics. 2013;89C:95–111. - PubMed

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