Characterization of expression, activity and role in antibacterial immunity of Anopheles gambiae lysozyme c-1

Abstract

There are eight lysozyme genes in the Anopheles gambiae genome. Transcripts of one of these genes, LYSC-1, increased in Anopheles gambiae cell line 4a3B by 24 h after exposure to heat-killed Micrococcus luteus. Lysozyme activity was also identified in conditioned media from the cell line from which the protein was purified to homogeneity using ion exchange and gel filtration. Mass spectrometric analysis of the purified protein showed 100% identity to lysozyme c-1. Purified lysozyme c-1 was tested against non-mosquito derived as well as culturable bacteria isolated from mosquito midguts. Lysozyme c-1 had negligible effects on the growth of most mosquito-derived bacteria in vitro but did inhibit the growth of M. luteus. Although Lys c-1 did not directly kill most bacteria, knockdown of LYSC-1 resulted in significant mortality in mosquitoes subjected to hemocoelic infections with Escherichia coli but not M. luteus thus suggesting that this protein plays an important role in antibacterial defense against selected bacteria.

Investigations on the role of a lysozyme from the malaria vector Anopheles dirus during malaria parasite development

“…Anopheles dirus A was reared under laboratory conditions in an insectary in an incubator set to 70–80% relative humidity and 25–27 °C at AFRIMS (Armed Forces Research Institute of Medical Sciences, Thailand) and at the Department of Entomology, University of Wisconsin- Madison, Wisconsin, USA according to previously described protocols (Paskewitz et al, 1999; Kajla et al, 2010 and 2011) with the modification that these mosquitoes were mated artificially.…”

“…We have investigated a group of antimicrobial enzymes called lysozymes (Li et al, 2005; Li and Paskewitz, 2006; Paskewitz et al, 2008; Kajla et al, 2010). These enzymes are defined by the ability to hydrolyze the 1–4 glycosidic bonds between N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) of the peptidoglycan (PGN) present in the cell walls of bacteria.…”

“…These enzymes are defined by the ability to hydrolyze the 1–4 glycosidic bonds between N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) of the peptidoglycan (PGN) present in the cell walls of bacteria. Lysozymes as antibacterial defense molecules have been well characterized in vertebrates (Jolles and Jolles, 1984; Markart et al, 2004) as well as in insects (Dunn, 1986; Hultmark, 1996; Kajla et al, 2010; Powning and Davidson, 1973; Jolles et al, 1979; Hultmark et al, 1980; Abraham et al, 1995). However, lysozymes have also recently been shown to inhibit melanization of non-biological targets in Anopheles gambiae (Li and Paskewitz, 2006) and to interact directly with the oocysts of Plasmodium berghei and P. falciparum in this mosquito (Kajla et al, 2011).…”

Antibacterial activity of lysozyme in the desert locust, Schistocerca gregaria (Orthoptera: Acrididae)

“…Spodoptera eridania (Anderson & Cook, 1979), B. mori (Abraham et al, 1995) and Gryllus texensis (Adamo, 2004), and E. coli is also considered to be an effective inducer of insect humoral immune responses in general (Erler et al, 2011) and of hemolymph lysozyme activity, in particular, e.g. B. mori (Sumida et al, 1992;Abraham et al, 1995), Melanoplus sanguinipes (Gillespie et al, 1993), Artogeia rapae (Bang & Yoe, 2005), S. frugiperda (Chapelle et al, 2009) and Anopheles gambiae (Kajla et al, 2010). Also, there is no clear-cut specificity in terms of pathogen recognition, signaling pathways, or effector molecules in the course of induction of humoral responses in insects (Marmaras & Lamproulou, 2009).…”

Different mosquito species host Wickerhamomyces anomalus (Pichia anomala): perspectives on vector-borne diseases symbiotic control

“…Concerning malaria, few studies have already shown the feasibility of approaches based on mosquito guts bacteria to deliver anti-Plasmodium effector molecules within the insect Jacobs-Lorena 2005, Riehle et al 2007). Many bacteria constitute the midgut microflora of some malaria vector mosquitoes (Dong et al 2009;Meister et al 2009;Kajla et al 2010) but, to date, the only stable association with a mosquito host is that described for bacteria of the genus Asaia (Favia et al 2007).…”