Immunity of the greater wax moth Galleria mellonella

Investigation of insect immune mechanisms provides important information concerning innate immunity, which in many aspects is conserved in animals. This is one of the reasons why insects serve as model organisms to study virulence mechanisms of human pathogens. From the evolutionary point of view, we also learn a lot about host–pathogen interaction and adaptation of organisms to conditions of life. Additionally, insect‐derived antibacterial and antifungal peptides and proteins are considered for their potential to be applied as alternatives to antibiotics. While Drosophila melanogaster is used to study the genetic aspect of insect immunity, Galleria mellonella serves as a good model for biochemical research. Given the size of the insect, it is possible to obtain easily hemolymph and other tissues as a source of many immune‐relevant polypeptides. This review article summarizes our knowledge concerning G. mellonella immunity. The best‐characterized immune‐related proteins and peptides are recalled and their short characteristic is given. Some other proteins identified at the mRNA level are also mentioned. The infectious routes used by Galleria natural pathogens such as Bacillus thuringiensis and Beauveria bassiana are also described in the context of host–pathogen interaction. Finally, the plasticity of G. mellonella immune response influenced by abiotic and biotic factors is described.     

Primary structure of apolipophorin-III from the greater wax moth,Galleria mellonella

The complete amino acid sequence of apolipophorin-III (apoLp-III), a lipid-binding hemolymph protein from the greater wax moth,Galleria mellonella, was determined by protein sequencing. The mature protein consists of 163 amino acid residues forming a protein of 18,075.5 Da. Its sequence is similar to apoLp-III from other Lepidopteran species, but remarkably different from the apoLp-IIIs of insects from other orders. As shown by mass spectrometric analysis, the protein carries no modifications. Thus, all of its known physiological functions, including its recently discovered immune response-stimulating activity, must reside in the protein itself.     

Characteristics of nuclear DNA of a Lepidoptera, the great wax moth Galleria mellonella, using reassociation kinetics

Reassociation kinetics of great wax moth--Galleria mellonella nuclear DNA short fragments was studied within the C0t values of 0.02 and 10(4). The least squares analysis of the experimental curve obtained revealed two components with C0t1/2 = 0.72 and C0t1/2 = 750 appropriately. The fraction of the component with C0t1/2 = 0.72 in the genome of great wax moth is 22% and that of the other one is 61%. There is also a rapid component which renatured at the C0t values less then 0,02. The fraction of this component in the genome is 17%. The great wax moth genome size determined kinetically is 4,83 X 10(8) base pairs. It was shown that the efficiency of DNA molecules network formation can qualify the genome studied as being a short or a long period of interspersion. On the basis that 80-90% of great wax moth DNA molecules participated in network formation which is inherent to the short period interspersion genomes, it was concluded that the great wax moth genome is of the Xenopus-like type.     

Purification and characterization of a male-specific protein in the hemolymph of the wax moth,Galleria mellonella L.

A male-specific protein (MSP) present only in males was identified from the hemolymph of the wax moth, Galleria mellonella L., by polyacrylamide gel electrophoresis (PAGE) and purified by anion-exchange chromatography. MSP has a native molecular mass of 55 kDa and consists of two 27-kDa subunits. An isoelectric point of MSP was measured to be approximately 5.8. MSP is a glycoprotein that contains 1.7% carbohydrate. The compositional analysis of carbohydrate component indicated a predominance of fructose and glucose. MSP also contains large amounts of asparagine, aspartic acid, glutamine, glutamic acid, and lysine but small amounts of tyrosine, methionine, and tryptophan. Western blot analysis of the hemolymph of each developmental stage indicated that MSP is present in the hemolymph of 8-day-old pupa and adult. Also, results from Western blotting indicated that MSP is not present in the tissues of larvae and of female adults but appears in the fat body of male pupae and adult and testis of adult. The fat body and testis of male pupae and adult were cultured in vitro to trace the place and time of MSP synthesis. The fat body began to synthesize MSP in late pupae and showed active synthesis during the adult stage. The distribution of MSP in the testis was observed by electron microscopic immunogold labeling, using the antibody against MSP. MSP is present between the germinal cysts and is taken up through the basal surface of the seminiferous tubular epithelium. Arch. Insect Biochem. Physiol. 37:257–268, 1998. © 1998 Wiley-Liss, Inc.     

A peptidomics study reveals the impressive antimicrobial peptide arsenal of the wax moth Galleria mellonella

The complete antimicrobial peptide repertoire of Galleria mellonella was investigated for the first time by LC/MS. Combining data from separate trypsin, Glu-C and Asp-N digests of immune hemolymph allowed detection of 18 known or putative G. mellonella antimicrobial peptides or proteins, namely lysozyme, moricin-like peptides (5), cecropins (2), gloverin, Gm proline-rich peptide 1, Gm proline-rich peptide 2, Gm anionic peptide 1 (P1-like), Gm anionic peptide 2, galiomicin, gallerimycin, inducible serine protease inhibitor 2, 6tox and heliocin-like peptide. Six of these were previously known only as nucleotide sequences, so this study provides the first evidence for expression of these genes. LC/MS data also provided insight into the expression and processing of the antimicrobial Gm proline-rich peptide 1. The gene for this peptide was isolated and shown to be unique to moths and to have an unusually long precursor region (495 bp). The precursor region contained other proline-rich peptides and LC/MS data suggested that these were being specifically processed and were present in hemolymph at very high levels. This study shows that G. mellonella can concurrently release an impressive array of at least 18 known or putative antimicrobial peptides from 10 families to defend itself against invading microbes.     

大蜡螟的性选择行为

【目的】针对大蜡螟Galleria mellonella L.的性选择行为进行系统观察分析,为大蜡螟性信息素全组分的结构鉴定及利用信息素行为调控技术防控该虫提供依据。【方法】分别对不同体重、不同日龄和不同交配经历的大蜡螟成虫进行标记,在红光灯下观察并记录大蜡螟雌雄虫的性选择行为。【结果】在（26±0.5）℃、相对湿度60%、全黑暗条件下,无论雌虫还是雄虫,均倾向于选择与之体重相接近的异性个体进行交配。雌雄成虫均偏向于选择3日龄的异性个体进行交配;雌虫对不同日龄雄虫的选择率大小顺序为3日龄> 5日龄> 1日龄,而雄虫对不同日龄雌虫的选择率大小顺序为3日龄>1日龄> 5日龄。交配经历影响大蜡螟的性选择行为,雌虫优先选择已交配的雄虫进行交配,选择率为74.6%;雄虫也优先选择已交配的雌虫进行交配,选择率为79.4%。【结论】雌雄虫体重、日龄和交配经历能不同程度的影响大蜡螟的性选择行为,这为进一步研究雌雄交配信号奠定基础。     

大蜡螟作为试验昆虫资源的利用现状

随着对资源昆虫的不断认识,人们的目光开始逐渐转到对大蜡螟Galleria mellonella L.的开发利用方面,而不再仅仅局限于对它的防治方面。近些年来,大蜡螟逐渐被作为试验昆虫用于一些生物的研究。文章主要介绍大蜡螟被用于昆虫病原线虫、寄生蜂、新型隐球菌Cryptococcus neoformans、抗菌肽、抗菌免疫机制等方面的研究。     

Apolipophorin-III in the greater wax moth, Galleria mellonella (Lepidoptera: Pyralidae).

The level of apolipophorin-III reached a maximum in the haemolymph of Galleria mellonella at the end of the feeding phase of the seventh larval instar and declined to a plateau value in the pupal and the adult stages. Apolipophorin-III was detected immunologically in fat body tissue, haemocyte lysates, and plasma. In its native state, apolipophorin-III may be associated with another protein with an apparent molecular mass of 77 kDa, possibly apolipophorin-II. Injections of octopamine did not cause lipid loading of high density lipophorin.     

Pheromone receptor system in the females of the greater wax moth Galleria mellonella

Electroantennogram studies of female Galleria mellonella showed a two-acceptor system for the sex pheromones, n-nonanal and n-undecanal, produced by the male. The nine carbon pheromone reacts with both acceptors, however, n-undecanal only reacts with the acceptor for the eleven carbon pheromone.     

Hearing and evasive behaviour in the greater wax moth, Galleria mellonella (Pyralidae)

Greater wax moths (Galleria mellonella L., Pyraloidea) use ultrasound sensitive ears to detect clicking conspecifics and echolocating bats. Pyralid ears have four sensory cells, A_1?4. The audiogram of G. mellonella has best frequency at 60 kHz with a threshold around 47 dB sound pressure level. A₁ and A₂ have almost equal thresholds in contrast to noctuids and geometrids. A₃ responds at + 12 to + 16 dB relative to the A₁ threshold. The threshold data from the A‐cells give no indication of frequency discrimination in greater wax moths. Tethered greater wax moths respond to ultrasound with short‐latency cessation of flight at + 20 to + 25 dB relative to the A₁ threshold. The behavioural threshold curve parallels the audiogram, thus further corroborating the lack of frequency discrimination. Hence, the distinction between bats and conspecifics is probably based on temporal cues. At a constant duty cycle (percentage of time where sound is on) the pulse repetition rate has no effect on the threshold for flight cessation, but stimulus duration affects both sensory and behavioural thresholds. The maximum integration time is essentially the same: 45 ms for the A₁‐cell and 50–60 ms for the flight cessation response. However, the slopes of the time‐intensity trade‐off functions are very different: ? 2.1 dB per doubling of sound duration for the A₁‐cell threshold, and ? 7.2 dB per doubling of sound duration for the behavioural threshold. The significance of the results for sexual acoustic communication as well as for bat defence is discussed.     

Decanal as a major component of larval aggregation pheromone of the greater wax moth,Galleria mellonella

Larvae of the greater wax moth (GWM), Galleria mellonella, a destructive pest of the honeybee (Apis mellifera), have been observed to display aggregation behaviours. However, the underlying mechanism by which these larvae come together remains unknown. We hypothesized that the GWM larvae detect, orient towards and utilize conspecific larval chemical cues to aggregate in groups. We used dual‐choice olfactometer assays to investigate the involvement of conspecific larval odours in their aggregation amongst 3–5th instar and 8th instar larvae. The assays revealed that only 8th instar larvae were significantly attracted to their odours and those emanating from newly spun cocoons. Coupled gas chromatography–mass spectrometry (GC‐MS) of larval head space odours analysis revealed the presence of four compounds: nonanal, decanal, tridecane and tetradecane in pupal and mature larval odour extracts. However, using synthetic compounds, behavioural assays showed that only decanal induced significant attraction, therefore, suggesting its role as a major component of the larval aggregation pheromone of GWM. Our findings reveal the involvement of volatile organic compounds in the aggregation behaviour of mature wax moth larvae and thereby offer prospects for the development of an odour‐baited in‐hive trapping management tool for wax moth larva.