The arylsulfatase- and phospholipase-rich venom of the plutoniumid centipede Theatops posticus.

Research on centipede venoms has led to the discovery of a diverse array of novel proteins and peptides, including those with homology to previously discovered toxin families (e.g., phospholipase A2s and pM12a metalloproteases) and novel toxin families not previously detected in venoms (e.g., ß-pore forming toxins and scoloptoxins). Most of this research has focused on centipedes in the order Scolopendromorpha, particularly those in the families Scolopendridae, Cryptopidae, and Scolopocryptopidae. To generate the first high-throughput venom characterization for a centipede in the scolopendromorph family Plutoniumidae, we performed venom-gland transcriptomics and venom proteomics on two Theatops posticus. We identified a total of 64 venom toxins, 60 of which were detected in both the venom-gland transcriptome and venom proteome and four of which were only detected transcriptomically. We detected a single highly abundant arylsulfatase B (ARSB) toxin, the first ARSB toxin identified from centipede venoms. As ARSBs have been detected in other venomous species (e.g., scorpions), ARSBs in T. posticus highlights a new case of convergent evolution across venoms. Theatops posticus venom also contained a much higher abundance and diversity of phospholipase A2 toxins compared to other characterized centipede venoms. Conversely, we detected other common centipedes toxins, such as CAPs and scoloptoxins, at relatively low abundances and diversities. Our observation of a diverse set of toxins from T. posticus venom, including those from novel toxin families, emphasizes the importance of studying unexplored centipede taxonomic groups and the continued potential of centipede venoms for novel toxin discovery and unraveling the molecular mechanisms underlying trait evolution.

A review of Vietnamese Scolopocryptops Newport, 1844 (Chilopoda: Scolopendromorpha), with a description of S. hoanglieni n. sp. and the updated generic list of species.

The Vietnamese fauna of the genus Scolopocryptops Newport, 1844 was reviewed based on recently collected specimens and material from Zoological Museum of the Moscow Lomonosov State University (ZMMU) and Naturhistorisches Museum Wien (NHMW). As a result of study of 164 specimens from 13 sampling regions, four species have been recognized, of which S. rubiginosus C.L. Koch, 1878 and S. spinicaudus Wood, 1862 already reported from Vietnam, S. hoanglieni described as n. sp., and S. capillipedatus (Takakuwa, 1938) for the first time recorded for this country. S. broelemanni esulcata Attems, 1938 was redescribed and confirmed as a valid. The COI fragments were obtained for the above mentioned species and the K2P genetic divergence between Vietnamese Scolopocryptops species was preliminarily estimated. New data on intraspecific variations of spiracle number in Scolopocryptops, an identification key for East Asian species and the general list of species of Scolopocryptops are provided.

Antihepatoma peptide, scolopentide, derived from the centipede scolopendra subspinipes mutilans.

BACKGROUND: Centipedes have been used to treat tumors for hundreds of years in China. However, current studies focus on antimicrobial and anticoagulation agents rather than tumors. The molecular identities of antihepatoma bioactive components in centipedes have not yet been extensively investigated. It is a challenge to isolate and characterize the effective components of centipedes due to limited peptide purification technologies for animal-derived medicines. AIM: To purify, characterize, and synthesize the bioactive components with the strongest antihepatoma activity from centipedes and determine the antihepatoma mechanism. METHODS: An antihepatoma peptide (scolopentide) was isolated and identified from the centipede scolopendra subspinipes mutilans using a combination of enzymatic hydrolysis, a Sephadex G-25 column, and two steps of high-performance liquid chromatography (HPLC). Additionally, the CCK8 assay was used to select the extracted fraction with the strongest antihepatoma activity. The molecular weight of the extracted scolopentide was characterized by quadrupole time of flight mass spectrometry (QTOF MS), and the sequence was matched by using the Mascot search engine. Based on the sequence and molecular weight, scolopentide was synthesized using solid-phase peptide synthesis methods. The synthetic scolopentide was confirmed by MS and HPLC. The antineoplastic effect of extracted scolopentide was confirmed by CCK8 assay and morphological changes again in vitro. The antihepatoma effect of synthetic scolopentide was assessed by the CCK8 assay and Hoechst staining in vitro and tumor volume and tumor weight in vivo. In the tumor xenograft experiments, qualified model mice (male 5-week-old BALB/c nude mice) were randomly divided into 2 groups (n = 6): The scolopentide group (0.15 mL/d, via intraperitoneal injection of synthetic scolopentide, 500 mg/kg/d) and the vehicle group (0.15 mL/d, via intraperitoneal injection of normal saline). The mice were euthanized by cervical dislocation after 14 d of continuous treatment. Mechanistically, flow cytometry was conducted to evaluate the apoptosis rate of HepG2 cells after treatment with extracted scolopentide in vitro. A Hoechst staining assay was also used to observe apoptosis in HepG2 cells after treatment with synthetic scolopentide in vitro. CCK8 assays and morphological changes were used to compare the cytotoxicity of synthetic scolopentide to liver cancer cells and normal liver cells in vitro. Molecular docking was performed to clarify whether scolopentide tightly bound to death receptor 4 (DR4) and DR5. qRT-PCR was used to measure the mRNA expression of DR4, DR5, fas-associated death domain protein (FADD), Caspase-8, Caspase-3, cytochrome c (Cyto-C), B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), x-chromosome linked inhibitor-of-apoptosis protein and Cellular fas-associated death domain-like interleukin-1ß converting enzyme inhibitory protein in hepatocarcinoma subcutaneous xenograft tumors from mice. Western blot assays were used to measure the protein expression of DR4, DR5, FADD, Caspase-8, Caspase-3, and Cyto-C in the tumor tissues. The reactive oxygen species (ROS) of tumor tissues were tested. RESULTS: In the process of purification, characterization and synthesis of scolopentide, the optimal enzymatic hydrolysis conditions (extract ratio: 5.86%, IC50: 0.310 mg/mL) were as follows: Trypsin at 0.1 g (300 U/g, centipede-trypsin ratio of 20:1), enzymolysis temperature of 46 °C, and enzymolysis time of 4 h, which was superior to freeze-thawing with liquid nitrogen (IC50: 3.07 mg/mL). A peptide with the strongest antihepatoma activity (scolopentide) was further purified through a Sephadex G-25 column (obtained A2) and two steps of HPLC (obtained B5 and C3). The molecular weight of the extracted scolopentide was 1018.997 Da, and the peptide sequence was RAQNHYCK, as characterized by QTOF MS and Mascot. Scolopentide was synthesized in vitro with a qualified molecular weight (1018.8 Da) and purity (98.014%), which was characterized by MS and HPLC. Extracted scolopentide still had an antineoplastic effect in vitro, which inhibited the proliferation of Eca-109 (IC50: 76.27 µg/mL), HepG2 (IC50: 22.06 µg/mL), and A549 (IC50: 35.13 µg/mL) cells, especially HepG2 cells. Synthetic scolopentide inhibited the proliferation of HepG2 cells (treated 6, 12, and 24 h) in a concentration-dependent manner in vitro, and the inhibitory effects were the strongest at 12 h (IC50: 208.11 µg/mL). Synthetic scolopentide also inhibited the tumor volume (Vehicle vs Scolopentide, P = 0.0003) and weight (Vehicle vs Scolopentide, P = 0.0022) in the tumor xenograft experiment. Mechanistically, flow cytometry suggested that the apoptosis ratios of HepG2 cells after treatment with extracted scolopentide were 5.01% (0 µg/mL), 12.13% (10 µg/mL), 16.52% (20 µg/mL), and 23.20% (40 µg/mL). Hoechst staining revealed apoptosis in HepG2 cells after treatment with synthetic scolopentide in vitro. The CCK8 assay and morphological changes indicated that synthetic scolopentide was cytotoxic and was significantly stronger in HepG2 cells than in L02 cells. Molecular docking suggested that scolopentide tightly bound to DR4 and DR5, and the binding free energies were-10.4 kcal/mol and-7.1 kcal/mol, respectively. In subcutaneous xenograft tumors from mice, quantitative real-time polymerase chain reaction and western blotting suggested that scolopentide activated DR4 and DR5 and induced apoptosis in SMMC-7721 Liver cancer cells by promoting the expression of FADD, caspase-8 and caspase-3 through a mitochondria-independent pathway. CONCLUSION: Scolopentide, an antihepatoma peptide purified from centipedes, may inspire new antihepatoma agents. Scolopentide activates DR4 and DR5 and induces apoptosis in liver cancer cells through a mitochondria-independent pathway.

Age-related changes in antioxidant defenses of the Mediterranean centipede Scolopendra cingulata (Chilopoda).

The activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), and glutathione S-transferase (GST), as well as the concentrations of sulfhydryl (SH) groups and glutathione (GSH) were analyzed in five age classes of the Mediterranean centipede Scolopendra cingulata as follows: embryo, adolescens, maturus junior, maturus, and maturus senior. The data obtained showed the presence of SOD, CAT, GSH-Px, GR, GST, and SH groups in embryos. The transition from embryo to adolescens was accompanied by an increase in the activities of all studied enzymes, in response to the increased production of ROS due to the increased metabolic activity of the centipede associated with growth and development. Our results show that trends in antioxidant enzyme (AOE) activities were not uniform among adult age classes, suggesting that maturus junior, maturus, and maturus senior differentially respond and/or have different susceptibility to ROS. On the other hand, GSH concentration in embryos was undetectable, highest in adolescens and decreased in the latter part of life. Pearson correlation analysis in embryos showed that the activities of the AOEs were strongly and positively correlated with each other but negatively correlated with GSH and SH groups. At later age classes, SOD, CAT, GSH-Px, GR, GSH, and SH groups were no longer significantly correlated with GST. In the discriminant analysis, the variables that separated the age classes were GR, GST, SH groups, and body length. Body length was directly related to the age of individuals, clearly indicating that development/aging affects the regulation of antioxidant defense in this species.

Active and passive mechanics for rugose terrain traversal in centipedes.

Centipedes coordinate body and limb flexion to generate propulsion. On flat, solid surfaces, the limb-stepping patterns can be characterized according to the direction in which limb-aggregates propagate, opposite to (retrograde) or with the direction of motion (direct). It is unknown how limb and body dynamics are modified in terrain with terradynamic complexity more representative of these animal's natural heterogeneous environments. Here, we investigated how centipedes that use retrograde and direct limb-stepping patterns, Scolopendra polymorpha and Scolopocryptops sexspinosus, respectively, coordinate their body and limbs to navigate laboratory environments which present footstep challenges and terrain rugosity. We recorded the kinematics and measured the locomotive performance of these animals traversing two rugose terrains with randomly distributed step heights and compared the kinematics with those on a flat frictional surface. Scolopendra polymorpha exhibited similar body and limb dynamics across all terrains and a decrease in speed with increased terrain rugosity. Unexpectedly, when placed in a rugose terrain, S. sexspinosus changed the direction of the limb-stepping pattern from direct to retrograde. Further, for both species, traversal of these rugose terrains was facilitated by hypothesized passive mechanics: upon horizontal collision of a limb with a block, the limb bent and later continued the stepping pattern. Although centipedes have many degrees of freedom, our results suggest these animals negotiate limb-substrate interactions and navigate complex terrains leveraging the innate flexibility of their limbs to simplify control.

Leech-Centipede Granules Suppress EndMT to Improve Erectile Dysfunction in Rats with Diabetes Mellitus via TGF-ß/Smad Pathway.

OBJECTIVE: To investigate whether Leech-Centipede (LC) Granules can improve erectile function in rats with diabetes mellitus-associated erectile dysfunction (DMED) through endothelial-to-mesenchymal transition (EndMT) inhibition. METHODS: Components of LC Granules were identified via ultra-high-performance liquid chromatography. Thirty male Sprague Dawley rats were injected with streptozotocin and fed continuously for 8 weeks to establish the DMED rat model. Rats with erectile dysfunction symptoms diagnosed using apomorphine were divided into DMED and low-, medium-, and high-doses LC groups (n=6 in each). The negative control (NC, n=6) and DMED groups were given 5 mL of deionized water via intragastric gavage, and the low-, medium- and the high-doses LC groups were administered LC at 1.6, 3.2, and 6.4 g/kg, respectively, via intragastric gavage for 4 weeks. The intracavernous pressure (ICP), mean arterial pressure (MAP), and nitric oxide (NO) levels in cavernous tissue were measured for each group. Quantitative reverse transcription-polymerase chain reaction and Western blot were used to detect mRNA and protein expressions of endothelial and mesenchymal markers. Immunofluorescence staining was used to observe α-SMA, and Masson's trichrome staining was performed to determine the myofiber/collagen ratio. RESULTS: A total of 474 active components were identified. After treatment, the ICP/MAP value and NO level were significantly higher in the medium- and high-dose LC groups than in the DMED group (P<0.05). Compared with the DMED groups, the medium- and high-dose groups LC significantly increased and decreased endothelial and mesenchymal markers expression, respectively (P<0.05). Tumor growth factor (TGF)ß R II, p-Smad2, and p-Smad3 levels were considerably higher following diabetes onset but reduced following LC intervention (P<0.05), except for TGF ß 1 (P>0.05). α-SMA expression was significantly higher in the DMED group and was reduced in all LC intervention groups (P>0.05). The myofiber/collagen ratio in the LC groups was higher than that in the DMED group but lower than that in the NC group (all P<0.05). CONCLUSIONS: LC Granules may improve the erectile function of DMED rats by suppressing TGF-ß/Smad pathway to reverse EndMT.

Sexually dimorphic characters of the ultimate legs in lithobiid centipedes (Myriapoda, Chilopoda, and Lithobiomorpha): Morphology and implications for reproductive behavior.

Many species of lithobiomorph centipedes present a pronounced sexual dimorphism reflected in remarkable structural modifications on the ultimate legs of males. Most records of these male secondary sexual characters addressed taxonomy, helping to identify and characterize species or diagnose genera, but information on their diversity, detailed morphology and possible function(s) is scarce. In this study, nine species of the two lithobiid genera Lithobius Leach, 1814 and Eupolybothrus Verhoeff, 1907 were investigated, using light and scanning electron microscopy to document the detailed morphology of secondary sexual characters of male ultimate legs. Secondary sexual characters affecting the cuticle of the ultimate legs are described in detail and found to often be associated with sensilla, interpreted here as chemo- and mechanoreceptors, and with clusters of pores, a hitherto undescribed pore-distribution for this group. The tibial nodule of the species Lithobius nodulipes Latzel, 1880, was additionally examined with histological semi-thin sections. These results revealed that the clustered pores are connected to glandular tissue, and are, based on their morphology, interpreted as openings of flexo-canal epidermal glands. The presence of various sensory and glandular structures associated with sexual dimorphism indicates a likely role during courtship and mating. The closely related species examined in this research show comparable dimorphic structures, which are otherwise species-specific. Morphological observations on secondary sexual structures inform on reproductive biology in groups like lithobiomorphs for which there are limited behavioral data.

Taxonomic Accounts and Phylogenetic Positions of the Far East Asian Centipedes Scolopocryptops elegans and S. curtus (Chilopoda: Scolopendromorpha).

The epigean centipede genus Scolopocryptops Newport, 1844 consists of two monophyletic lineages, the "Asian/North American" and "Neotropical/Afrotropical" groups. Most of the "Asian/North American" species bear the complete sulcus/sulci along the lateral margin of the cephalic plate and sternites lacking sulci, whereas Japanese Scolopocryptops elegans (Takakuwa, 1937) bears short lateral sulci on the cephalic plate and Taiwanese Scolopocryptops curtus (Takakuwa, 1939) lacks the cephalic marginal sulci, and both species bear a longitudinal sternal sulcus. The taxonomic accounts of S. elegans and S. curtus were revisited in this study based on newly collected specimens. We found that these two species share a characteristic of the second maxilla, that they lack the transparent margin on the dorsal brush, which distinguishes them from other "Asian/North American" species. Scolopocryptops elegans and S. curtus can be distinguished from each other by the characters of their antennal articles, cephalic plate, forcipular coxosternite, tergite 23, and coxopleuron. Phylogenetic analyses using nuclear 28S ribosomal RNA and mitochondrial cytochrome c oxidase subunit I sequences confirmed that S. elegans and S. curtus are closely related and form a single clade sister to a clade comprising all the other "Asian/North American" Scolopocryptops species.

Necrotizing Soft-Tissue Infection of the Trunk Resulting From Wound Caused by a Centipede: A Case Report.

BACKGROUND Centipede envenomation is usually mild, but a review of the existing literature revealed a more serious course in a small proportion of patients. In fact, necrotizing soft-tissue infections have been reported following centipede stings in a small number of cases and require early diagnosis and treatment because of a high mortality rate. CASE REPORT A 78-year-old man was stung by a centipede on the left abdomen. Treatment with antimicrobial agents was started due to cellulitis, but extensive erythema developed from the left chest to the left buttock. Six days after being stung, he visited our hospital. Necrotizing soft-tissue infection was diagnosed and treated immediately with antibiotics and debridement on the left side of the abdomen and chest. Group A Streptococcus was detected in the fascia. The wound was left partially open and washed daily, resulting in gradual improvement of the wound condition. On hospitalization day 8, the open wound was able to be closed. Antimicrobial therapy was completed on hospitalization day 16. The patient showed good progress. CONCLUSIONS Centipede stings are not rare in tropical and subtropical regions, and most occurrences of centipede envenomation cause only local symptoms. However, we believe that even wounds caused by centipedes should be monitored, given the possibility of subsequent severe infection, as in the present case. In addition, the causative organisms identified in the present patient with necrotizing soft-tissue infection following a centipede sting were commensal bacteria of the skin. Future research is thus needed to clarify the relationship between these causative organisms and centipedes.

A Rearrangement of the Mitochondrial Genes of Centipedes (Arthropoda, Myriapoda) with a Phylogenetic Analysis.

Due to the limitations of taxon sampling and differences in results from the available data, the phylogenetic relationships of the Myriapoda remain contentious. Therefore, we try to reconstruct and analyze the phylogenetic relationships within the Myriapoda by examining mitochondrial genomes (the mitogenome). In this study, typical circular mitogenomes of Mecistocephalus marmoratus and Scolopendra subspinipes were sequenced by Sanger sequencing; they were 15,279 bp and 14,637 bp in length, respectively, and a control region and 37 typical mitochondrial genes were annotated in the sequences. The results showed that all 13 PCGs started with ATN codons and ended with TAR codons or a single T; what is interesting is that the gene orders of M. marmoratus have been extensively rearranged compared with most Myriapoda. Thus, we propose a simple duplication/loss model to explain the extensively rearranged genes of M. marmoratus, hoping to provide insights into mitogenome rearrangement events in Myriapoda. In addition, our mitogenomic phylogenetic analyses showed that the main myriapod groups are monophyletic and supported the combination of the Pauropoda and Diplopoda to form the Dignatha. Within the Chilopoda, we suggest that Scutigeromorpha is a sister group to the Lithobiomorpha, Geophilomorpha, and Scolopendromorpha. We also identified a close relationship between the Lithobiomorpha and Geophilomorpha. The results also indicate that the mitogenome can be used as an effective mechanism to understand the phylogenetic relationships within Myriapoda.

Presence of morphological integration and modularity of the forcipular apparatus in Lithobius melanops (Chilopoda: Lithobiomorpha: Lithobiidae).

The presence of morphological integration and modularity of the forcipular apparatus, despite its evolutionary significance, has not been analyzed in centipedes. This morphological structure has a crucial role in feeding and defense, thanks to its poisonous part (forcipules), which is important for catching the prey. The aims of our study were: i) to test the hypothesis of modularity of the forcipular apparatus in centipede Lithobius melanops; and ii) to investigate the influence of allometry on overall morphological integration in the aforementioned species using a geometric morphometric approach. The presence of fluctuating asymmetry was obtained by Procrustes ANOVA. Allometry was significant only for the symmetric component of the forcipular apparatus. The modularity hypothesis was not accepted, because the covariance coefficients for symmetric and asymmetric components were lower than 89.5% and 72.1% (respectively) of other RV coefficients obtained by a random contiguous partition of the forcipular apparatus. Results of the present study indicate that allometry does increase the level of morphological integration in the forcipular apparatus. According to our results, the forcipular coxosternite and forcipules could not be considered as separate modules; namely, they probably share similar developmental pathways and function in different forms of behavior and survival in L. melanops.

A new species and a new record of the genus Otostigmus Porat, 1876 (Chilopoda: Scolopendromorpha: Scolopendridae) in Vietnam.

Otostigmus consonensis sp. nov. was described from Vietnam, and O. sulcipes Verhoeff, 1937 was recorded for the first time in this country. The new species can be recognized by having 18 antennomeres including 2.32.5 glabrous basal ones, three coxosternal teeth, tergites 520 with complete paramedia sutures, sternites with incomplete paramedian sutures, and the ultimate leg with 1115 prefemoral spines. The fragment of the COI gene was extracted for each species; thus, a new species and a record of O. sulcipes were supported by the COI genetic distances and the corresponding phylogenetic analysis.

The complete mitochondrial genome of Thereuopoda clunifera (Chilopoda: Scutigeridae) and phylogenetic implications within Chilopoda.

We determined the complete mitochondrial genome of Thereuopoda clunifera (Chilopoda: Scutigeridae) to clarify the phylogenetic status within Chilopoda. Using Sanger sequencing and next-generation sequencing technologies, the entire mitogenome of T. clunifera was assembled and annotated, with 14,898 bp in length and 37 genes (13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes), which are usually found in arthropod mitogenomes. Only one D-loop contained no repeat element. The base composition of T. clunifera was found to be A + T content of 69.55% and G + C content of 30.45%. The AT-skew of T. clunifera was positive, while the GC-skew was negative. The gene order of T. clunifera was identical to that of Scutigera coleoptrata that has been unique among those so far determined for the Arthropoda. We also performed phylogenetic analyses of 25 Myriapoda species to further explore the taxonomic and evolutionary relationships within Myriapoda and Chilopoda. Phylogenetic analyses supported that the division of Chilopoda into subclasses Notostigmophora and Pleurostigmophora.

On the dates of publication of four European species of Scolopendra Linnaeus, 1758 described by C. L. Koch (Myriapoda, Chilopoda).

Current studies on European Scolopendra Linnaeus, 1758 revealed inconsistencies in the use of the date of publications containing original descriptions by C. L. Koch. These dates are reviewed in the present paper. As a result, the following commonly attributed dates of description have to be amended: S. clavipes C. L. Koch, 1847, S. italica C. L. Koch, 1837, S. graeca C. L. Koch, 1847, and S. germanica C. L. Koch, 1837. The work containing the original description of all these taxa was published in 1836 by C. L. Koch as Heft 9 of the rare series Deutschlands Crustaceen, Myriapoden und Arachniden. Two of these taxa were introduced by a short, inconspicuous paragraph and without illustration. The remaining two were wrongly dated short time after their descriptions, which were never questioned and have still being used until today.

Hyperbaric oxygen therapy of soft tissue necrosis due to centipede bite in a patient with diabetes.

OBJECTIVE: The purpose of this study is to demonstrate that hyperbaric oxygen therapy (HBOT) is an option for the management of rapidly progressive tissue necrosis after centipede bites in patients with diabetes. METHOD: In this case report, we introduce a patient with diabetes with soft tissue necrosis and secondary infection due to a centipede bite, who was treated with a multidisciplinary approach including HBOT. RESULTS: In this case study, HBOT, applied in the treatment of rapidly developing cellulitis after a centipede bite in a patient with diabetes, accelerated wound healing. Deep soft tissue infection stopped progression to necrotising fasciitis and prevented possible amputation, and facilitated the patient's return to social life in a short time. CONCLUSION: HBOT can be used in combination with other local and systemic, due to its anti-venom effect and treatment of extremity-threatening infection.

Centipede Venom: A Potential Source of Ion Channel Modulators.

Centipedes are one of the most ancient and successful living venomous animals. They have evolved spooky venoms to deter predators or hunt prey, and are widely distributed throughout the world besides Antarctica. Neurotoxins are the most important virulence factor affecting the function of the nervous system. Ion channels and receptors expressed in the nervous system, including NaV, KV, CaV, and TRP families, are the major targets of peptide neurotoxins. Insight into the mechanism of neurotoxins acting on ion channels contributes to our understanding of the function of both channels and centipede venoms. Meanwhile, the novel structure and selective activities give them the enormous potential to be modified and exploited as research tools and biological drugs. Here, we review the centipede venom peptides that act on ion channels.

Hazards related to the presence of cadmium in food - Studies on the European soil centipede, Lithobius forficatus.

The soil is an environment rich in numerous potentially toxic substances/elements when present at elevated concentrations. They can be transported through the successive levels of the trophic chain. Animals living in a contaminated environment or eating contaminated food can accumulate potentially toxic elements in their bodies. One of the potentially toxic metals is cadmium, which accumulates significantly in soils. The aim of our research was to evaluate the changes caused by cadmium supplied with the food administered to invertebrates living in uncontaminated soil. The results were compared with those obtained for animals raised in contaminated soil, where cadmium entered the body via the epidermis. As the material for studies, we chose a common European soil centipede, Lithobius forficatus. Adult specimens were divided into the following experimental groups: C - control animals, Cd12 and Cd45 - animals fed with Chironomus larvae maintained in water containing 80 mg/l CdCl2, for 12 and 45 days, respectively. The material was analyzed using qualitative and quantitative analysis (transmission electron microscopy, confocal microscopy, flow cytometry, atomic absorption spectrometry). Eventually, we can conclude that the digestive system is an effective barrier against the effects of toxic metals on the entire organism, but among the gonads, ovaries are more protected than testes, however, this protection is not sufficient. Accumulation of spherites and mitochondrial alterations are probably involved in survival mechanisms of tissues after Cd intoxication.

Bioactive Peptides and Proteins from Centipede Venoms.

Venoms are a complex cocktail of biologically active molecules, including peptides, proteins, polyamide, and enzymes widely produced by venomous organisms. Through long-term evolution, venomous animals have evolved highly specific and diversified peptides and proteins targeting key physiological elements, including the nervous, blood, and muscular systems. Centipedes are typical venomous arthropods that rely on their toxins primarily for predation and defense. Although centipede bites are frequently reported, the composition and effect of centipede venoms are far from known. With the development of molecular biology and structural biology, the research on centipede venoms, especially peptides and proteins, has been deepened. Therefore, we summarize partial progress on the exploration of the bioactive peptides and proteins in centipede venoms and their potential value in pharmacological research and new drug development.

Venom resistance mechanisms in centipede show tissue specificity.

Venomous animals utilize venom glands to secrete and store powerful toxins for intraspecific and/or interspecific antagonistic interactions, implying that tissue-specific resistance is essential for venom glands to anatomically separate toxins from other tissues. Here, we show the mechanism of tissue-specific resistance in centipedes (Scolopendra subspinipes mutilans), where the splice variant of the receptor repels its own toxin. Unlike the well-known resistance mechanism by mutation in a given exon, we found that the KCNQ1 channel is highly expressed in the venom gland as a unique splice variant in which the pore domain and transmembrane domain six, partially encoded by exon 6 (rather than 7 as found in other tissues), contain eleven mutated residues. Such a splice variant is sufficient to gain resistance to SsTx (a lethal toxin for giant prey capture) in the venom gland due to a partially buried binding site. Therefore, the tissue-specific KCNQ1 modification confers resistance to the toxins, establishing a safe zone in the venom-storing/secreting environment.