A first molecular characterization of the scorpion telson microbiota of Hadrurus arizonensis and Smeringurus mesaensis

Scorpions represent an ancient lineage of arachnids that have radiated across the globe and are incredibly resilient-since some thrive in harsh environments and can exist on minimal and intermittent feedings. Given the emerging importance of microbiomes to an organism's health, it is intriguing to suggest that the long-term success of the scorpion bauplan may be linked to the microbiome. Little is known about scorpion microbiomes, and what is known, concentrates on the gut. The microbiome is not limited to the gut, rather it can be found within tissues, fluids and on external surfaces. We tested whether the scorpion telson, the venom-producing organ, of two species, Smeringurus mesaensis and Hadrurus arizonensis, contain bacteria. We isolated telson DNA from each species, amplified bacterial 16S rRNA genes, and identified the collection of bacteria present within each scorpion species. Our results show for the first time that telsons of non-buthid scorpion species do indeed contain bacteria. Interestingly, each scorpion species has a phylogenetically unique telson microbiome including Mollicutes symbionts. This study may change how we view scorpion biology and their venoms.

Cophylogenetic analysis suggests cospeciation between the Scorpion Mycoplasma Clade symbionts and their hosts

Scorpions are predator arachnids of ancient origin and worldwide distribution. Two scorpion species, Vaejovis smithi and Centruroides limpidus, were found to harbor two different Mollicutes phylotypes: a Scorpion Mycoplasma Clade (SMC) and Scorpion Group 1 (SG1). Here we investigated, using a targeted gene sequencing strategy, whether these Mollicutes were present in 23 scorpion morphospecies belonging to the Vaejovidae, Carboctonidae, Euscorpiidae, Diplocentridae, and Buthidae families. Our results revealed that SMC is found in a species-specific association with Vaejovidae and Buthidae, whereas SG1 is uniquely found in Vaejovidae. SMC and SG1 co-occur only in Vaejovis smithi where 43% of the individuals host both phylotypes. A phylogenetic analysis of Mollicutes 16S rRNA showed that SMC and SG1 constitute well-delineated phylotypes. Additionally, we found that SMC and scorpion phylogenies are significantly congruent, supporting the observation that a cospeciation process may have occurred. This study highlights the phylogenetic diversity of the scorpion associated Mollicutes through different species revealing a possible cospeciation pattern.

Inducible antibacterial response of scorpion venom gland

Innate immunity is the first line defense of multicellular organisms that rapidly operates to limit aggression upon exposure to pathogen microorganisms. Although the existence of some antibacterial peptides in scorpion venoms suggests that venom gland could be protected by these effector molecules, antibacterial activity of venom itself has not been assessed. In this study, we reported the antibacterial activity of the venom of Chinese scorpion Buthus martensii. Protease K digestion test indicated that it is venom peptide/protein components, as key players, which are involved in such antibacterial response. As the first step toward studying molecular mechanism of scorpion venom gland immunity, we established an infection model which supports inducible antibacterial response of scorpion venom gland. A known B. martensii antibacterial peptide gene BmKb1 was up-regulated at the transcriptional level after venom gland was challenged, suggesting its key defense role. This is further strengthened by the presence of several immune response elements in the BmKb1 promoter region. Our work thus provides the first evidence supporting the role of venom antibacterial peptides (ABPs) in controlling scorpion venom gland infection and lays a basis for characterizing related components involved in regulation of scorpion venom gland ABP gene expression.

[Microbial diversity in scorpion intestine (Buthus martensii Karsch)]

Scorpion is an important officinal animal, and has a high nutritional value. In this study, the culture-independent and culture-dependent methods were used to investigate the microbial diversity in the scorpion's intestine. Results based on culture-independent method showed the bacteria to be related to alpha, beta, gamma-proteobacteria. Bacteria isolated by the culture-dependent method were high G + C, gram-positive bacteria. The genera Enterobacter, Serratia and Ochrobactrum were detected by both methods. To sum up the results from the two methods, the bacteria in scorpion intestine belong to 23 genera, which are Enterobacter, Serratia, Pseudomonas, Acinetobacter, Aeromonas, Citrobacter, Pedobacter, Delftia, Ralstonia, Ochrobactrum, Sphingomonas, Exiguobacterium, Gordonia, Nocardia, Rhodococcus, Janibacte, Kocuria, Micrococcus, Agromyces, Microbacterium, Agrococcus, Deinococcus, Ornithinimicrobium, and some uncultured species. The two methods have both advantages and shortcomings. However, when used simultaneously, they complement each other.

Wolbachia Are Present in Southern African Scorpions and Cluster with Supergroup F

The presence and distribution of the intracellular bacteria Wolbachia in the arthropod subphylum Chelicerata (including class Arachnida) has not been extensively explored. Here we report the discovery of Wolbachia in scorpions. Five strains found in host species of the genus Opistophthalmus (Southern African burrowing scorpions) have been characterized by Multilocus Sequence Typing and by Wolbachia Surface Protein. Phylogenetic analyses indicate clustering in the supergroup F and a high genetic relatedness among all scorpion strains as a result of a potential transmission within the host genus. The F-group is an uncommon lineage compared to the A and B supergroups, although it is present in a broad range of hosts (including insects, filarial nematodes, and now arachnids) and across a large geographical area (e.g., North America, Africa, Europe, and Australia). It also shows no evidence of recombination and has a significantly higher genetic diversity than supergroup A and B. Overall, this pattern suggests an older radiation of F-strains with respect to A and B-strains, followed by limited horizontal transmission across host genera and reduced genetic flux among strains. A more extensive sampling of supergroup F-strains is required to confirm this scenario.

[The hygienic examination and quality research of Chinese crude drug scorpion]

We selected the method of hygienic test to determinate the infection of colibacilli, salmonelli, mixed bacteria, mould fungus and yeasts on Chinese crude drug scorpion from 29 commerical samples in different storaged period, habitats and commerical standard. The results showed there were not colibacilli and salmonelli in all 29 samples, but infectious mixed bacteria rate is 100%, which is 2.1 times more than salty scorpion in 29 tested samples, and the infectious fungi rate is 72.4%. The fungi of salty scorpion is 15% more than fresh scorpion. The quantity of infected yeasts on salty scorpion is much more than scorpion. There are 4 species of fungi such as Alternaria neesex Wallroth, Aspergillus fumigatus Fresenius, Nocarcia sp. and Tricophyton violaceum Sabouraud. Because of infectious pathogenic bacteria rate is so high, we suggest to increase the item of hygienic test to control the quality of crude drug scorpion and strengthen the administration of commerical drugs, so as to reduce the contaminative condition.

[Scorpion toxins and defensins]

The scorpion venoms possess many neurotoxic peptides which constitute a group of molecular families with a common architecture and a high degree of polymorphism. This architecture is found also in circulating antimicrobial peptides belonging to the defensins family, which are especially structurally related to the blocking potassium channels neurotoxins. The diversification in functions with a unique architectural scheme is discussed taking in account the biophysiological characteristics of the scorpion order.

[A cytoplasmic virus in the scorpion Buthus occitanus Amoreux]

Isometric virus particles, 60 nm in diameter, have been isolated from diseased scorpions. The virus is pathogenic after ingestion. Its morphogenesis occurs in the cytoplasm of hepatopancreas cells which are totally destroyed at the end of the disease.