@conference{
author = "Milovanović, Jelena and Ilić, Bojan and Makarov, Slobodan and Đorđević Aleksić, Jelena and Stevanović, Aleksandra and Malešević, Anastasija and Vuković-Gačić, Branka",
year = "2021",
abstract = "INTRODUCTION:
Different orders within the class Diplopoda possess a variety of chemical compounds in their defense secretions: quinones, phenolics, alcohols, aldehydes, ketones, esters, alkaloids, cyanogenic compounds. Defensive secretions of species from the order Julida are regarded as the most complex within Diplopoda, and they are blends of several classes of chemical com- pounds: quinones, esters and ketones. Numerous biological activities of these secretions have been reported: antimicrobial, antioxidative, antineurodegenerative, cytotoxic and embryotoxic on zebrafish. Besides zebrafish embryos, Artemia salina is one of the common model organisms in toxicity assessment which has not been used for screening of toxicity of millipedes’ defensive secretions.
OBJECTIVES:
The main goal of this study was to examine the toxic effects of defensive secretions of two species from the order Julida [Megaphyllum bosniense (MBO) and M. unilineatum (MUN)] using Artemia salina (ARC test).
METHOD / DESIGN:
Adult individuals of M. bosniense were collected during April and May of 2021 on Mt. Avala, near Belgrade, while adults of M. unilineatum were collected during the same period in the Krnjača, suburb of Belgrade. After the capture, millipedes were kept in plastic boxes containing ground cover from the collecting site. The boxes were regularly sprayed with water to maintain high humidity. Due to the fact that the sample was female-biased, defensive secretions of female specimens were used for further analyses. Excretion of defensive secretions was elicited from glands of mentioned species via mechanical stress in closed glass vials. Secretions collected from both species were dissolved in 10 ml of hexane, concentrated under reduced pressure in a rotary evaporator (Rotavapor R-210, Buchi) at 40°C to a dry residue, and redissolved in 50% dimethylsulphoxide (DMSO). The stock concentration of extracts used in ARC test was 20 mg/mL. Before treatments, eggs of A. salina were incubated for 72h with constant lighting and aeration. For the purposes of the experiment, stage II and III larvae were used (separated by phototaxis in 300 ml of seawater). In a plate with 24 wells, 900 μl of seawater with larvae (10-15 per well) was placed and then 100 μl of tested extracts (range of concentrations 0,1 mg/mL - 0,003125 mg/mL) was added. Potassium dichromate (K2Cr2O7) was used as a positive control and DMSO was used as solvent control. The total number of individuals per well was counted after 24h and 48h, as well as the number of living and dead individuals. These data were used for esti- mation of survival rate and determination of LC50 value. The experiment was done in triplicate.
RESULTS:
Our results show that secretions from both species exhibit a toxic effect on the survival of the chosen model organism, with the MBO extract showing weaker activity in comparison with MUN extract. The LC50 value after 24h was about the same for both species (LC50=73,23 μg/mL for MBO and LC50=68,56 μg/mL for MUN). The LC50 value for MBO after 48h was 47,18 μg/ mL, while LC50 value in the same period for MUN was 29,12 μg/mL. Positive control (LC50= 13,5 μg/mL) showed three times stronger effects in relation to MBO and twice as strong when compared to MUN extract. It has also been shown that the num- ber of surviving individuals decreases with increasing concentration of tested extracts and the increasing incubation time.
CONCLUSIONS:
The defense secretions of both tested millipede species show toxic effects in the ARC test. It is shown that MBO extract has a weaker toxic effect than the MUN extract. This result can be linked with the fact that esters of long-chain fatty acids are dominant compounds in MBO, while MUN is almost exclusively benzoquinone-based. Esters detected in MBO are generally regarded as low-toxic compounds, but with the potential to interact with compounds from other chemical classes. However, as MBO achieved toxic effects and many esters that are detected in MBO are new natural products and their biological potential is unknown, further extensive studies are needed to determine their toxicological potential.",
publisher = "The International Bioscience Conference (2021; Novi Sad)",
journal = "International Bioscience Conference and the 8th International PSU – UNS Bioscience Conference – IBSC2021",
title = "Acute toxicity assessment of defense secretions of Megaphyllum bosniense (Verhoeff, 1897) and M. unilineatum (C. L. Koch, 1838) (Diplopoda, Julida) on Artemia salina.",
pages = "54-53",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2178"
}
