Biology subjects

Eichberg, J.

Publications and source records attributed to Eichberg, J..

6 recordsLinked to original sources

bioRxiv2026

Ontogenetic variation in composition and bioactivity of common adder (Vipera berus) venom revealed by genome-guided proteomics and in vitro functional assays

1Ontogenetic shifts in diet are well documented in snakes and are increasingly linked to age-related venom variation. The common adder, Vipera berus, exhibits a dietary transition from predominantly ectothermic prey in its early life to increasingly incorporating endothermic prey as an adult. Here, we investigate whether this dietary shift is reflected in age-related changes in the venom composition and bioactivity of V. berus. Venoms from captive-bred V. berus from Germany were obtained and pooled across five age groups, from neonates to adults. Venom profiles were assessed by SDS-PAGE and genome-guided shotgun proteomics, with quantification based on normalized spectral abundance factors (NSAF) using a toxin-gene catalogue generated from a novel V. berus genome assembly. In parallel, we assayed general protease and PLA2 activities, as well as FXa-, thrombin-, and plasmin-like activities, and cytotoxicity toward mammalian cell lines. We identified two distinct age-related venom phenotypes (ontotypes): an svMP/CTL-rich ontotype A ([≤]1 year) and an svSP/PLA2-rich ontotype B ([≥]2 years). Functionally, protease activity decreased with age, whereas thrombin-like, plasmin-like and PLA2 activities, and cytotoxicity, increased. Our findings indicate an ontogenetic shift in composition and activities of V. berus venom that parallels dietary transitions and potentially reflect adaptation to differing prey physiologies.

biochemistry↗

bioRxiv2025

A genome-guided atlas to the composition, activity, and β-bungarotoxin dimerization in many-banded krait venom inferred by functional venomics

1Snakebite is a neglected tropical disease claiming [~]140,000 lives every year. One of the most medically relevant snakes of Asia is the many-banded krait (Bungarus multicinctus). Approximately 8% of the global human population is at risk of being envenomated by this species, able to cause fatal neurotoxicity. Here, we present a proteogenomic and functional assessment of the B. multicinctus venom via genome-guided bottom-up and top-down proteomics, combined with traditional protein profiling and bioassays. We report its venom profile alongside the primary structures of its toxins, revealing a relatively simple venom containing 55 components from 16 protein families. It is largely composed by three-finger toxins and phospholipase A2, besides acetylcholinesterase and snake venom metalloprotease. Top-down data unveiled the diversity of the highly lethal {beta}-bungarotoxins and allowed us to infer the complex dimerization patterning of these multi-domain neurotoxins. Our functional analysis revealed that B. multicinctus venom exerts potent phospholipase A2 and acetylcholinesterase activities, but protease activity as well as effects on cell viability and release of second messengers were virtually absent. This suggests, that B. multicinctus venom causes its devastating neurotoxic symptoms due to a heavy reliance on phospholipase A2 and acetylcholinesterase, but without impairing viability of neurons nor via interference of second messenger release. Antibacterial and antiviral screens further revealed activity against some pathogenic microbes that warrant further translational investigations. A comparison to previously published venom proteomes of B. multicinctus and its congeners suggests, that intraspecific venom variation occurs more widely in kraits than previously acknowledged and deserves higher attention. Overall, our investigation provides pivotal new insights into the biochemistry and pathophysiology of one of earths most lethal snakes and represents an important resource to inform future proteogenomic and functional studies in krait venom and beyond.

molecular biology↗

bioRxiv2025

Low extent of sex-based venom variation in Earth's most widespread viper, the common adder (Vipera berus)

Snake venom is an ecologically critical functional trait, primarily applied for foraging and accordingly shaped by selective pressures. Recent insights underpinned the high variability of snake venoms down to the intraspecific level, with regional, ontogenetic, and seasonal variation being mostly investigated. In contrast, sex-based venom variation has received considerably less attention so far, and its influence on venom compositions in vipers is virtually unknown. The common adder (Vipera berus) is a promising model species to explore this subject because of a described sexual dimorphism and its wide distribution, which promises a noteworthy degree of adaptability and venom plasticity. Here, we tested for sex-based venom variation in Central European V. berus by comparing venom profiles and bioactivity. Proteomics, paired with SDS-PAGE and RP-HPLC, revealed highly similar venom profiles. Likewise, phospholipases A2 and proteases bioactivity profiling, and bioassays targeting the coagulation cascade and mammalian cell lines revealed similar activity spectra. Hence, our analysis does not show a noteworthy extent of sex-based intraspecific venom variation in V. berus. We further discuss our data in light of the species venom profile at larger geographic scales, its clinical relevance, and the need for more standardized approaches when investigating venom variability. Our work provides novel insights into the venom biology of Earths most widespread viper, and serves as a foundation upon which future works can build.

biochemistry↗

bioRxiv2024

Comparative venom analysis between melanistic and normally-colored phenotypes of the common adder (Vipera berus)

1Snake venom is an ecologically-relevant functional trait directly linked with a snakes fitness and survival, facilitating predation and defense. Snake venom variation occurs at all taxonomic levels, but the study of variation at intraspecific level is still in its early stages. The common adder (Vipera berus) exhibits considerable variation in color phenotypes across its distribution range. Melanistic (fully black) individuals are the subject of myths and fairytales, and in German folklore such "hell adders" are considered more toxic than their normally-colored conspecifics. However, these claims have never been formally tested. Here, we provide the first comparative analysis of venoms from melanistic and normally-colored common adders. Specifically, we compared the venom profiles by SDS-PAGE and RP-HPLC, and tested the protease, phospholipase A2 and cytotoxic activities of the venoms of both phenotypes. Phospholipase A2 activity was similar in both phenotypes, whereas general protease activity was higher in the melanistic venom, which was also more cytotoxic at two concentrations (6.25 and 12.5 {micro}g/ml). These minor differences between the venoms of melanistic and normally-colored adders are unlikely to be of clinical relevance in the context of human envenomation. In light of our results, the claim that melanistic adders produce more toxic venom than their normally-colored conspecifics appears rooted entirely in folklore.

molecular biology↗

bioRxiv2024

Engineering a wolf spider A-family toxin towards increased antimicrobial activity but low toxicity

Peptides with insecticidal, antimicrobial and/or cytolytic activities, also known as spider venom antimicrobial peptides (AMPs), can be found in the venoms of RTA-clade spiders. They show translational potential as therapeutic leads. A set of 52 AMPs has been described in the Chinese wolf spider (Lycosa shansia), and many have been shown to exhibit antibacterial effects. Here we explored the potential to enhance their antimicrobial activity using bioengineering. We generated a panel of artificial derivatives of an A-family peptide and screened their activity against selected microbial pathogens, vertebrate cells and insects. In several cases, we increased the antimicrobial activity of the derivatives while retaining the low cytotoxicity of the parental molecule. Furthermore, we injected the peptides into adult Drosophila suzukii and found no evidence of insecticidal effects, confirming the low levels of toxicity. Our data therefore suggest that spider venom linear peptides can be modified into more potent antimicrobial agents that could help to battle infectious diseases in the future.

bioengineering↗

bioRxiv2022

Robustness of a multivariate composite score when evaluating distress of animal models for gastrointestinal diseases

The fundament of an evidence-based severity assessment in laboratory animal science is reliable distress parameters. Many readouts are used to evaluate and determine animal distress and the severity of experimental procedures. Therefore, we analyzed four distinct parameters like the body weight, burrowing behavior, nesting, and distress score in the four gastrointestinal animal models (pancreatic ductal adenocarcinoma (PDA), pancreatitis, CCl4 intoxication, and bile duct ligation (BDL)). Further, we determined the parameters robustness in various experimental subgroups due to slight variations like drug treatment or telemeter implantations. We used non-parametric bootstrapping to get robust estimates and 95 % confidence intervals for the experimental groups. It was found that the performance of the readout parameters is model-dependent and that the distress score is prone to experimental variation. On the other hand, we also found that burrowing and nesting can be more robust than, e.g., the body weight when evaluating PDA. However, the body weight still was highly robust in BDL, pancreatitis, and CCl4 intoxication. To address the complex nature of the multi-dimensional severity space, we used the Relative Severity Assessment (RELSA) procedure to combine multiple distress parameters into a score and mapped the subgroups and models against a defined reference set obtained by telemeter implantation. This approach allowed us to compare the severity of individual animals in the experimental subgroups using the maximum achieved severity (RELSAmax). With this, the following order of severity was found for the animal models: CCl4 < PDA {approx} Pancreatitis < BDL. Furthermore, the robustness of the RELSA procedure and outcome was externally validated with a reference set from another laboratory also obtained from telemeter implantation. Since the RELSA procedure reflects the multi-dimensional severity information and is highly robust in estimating the quantitative severity within and between models, it can be deemed a valuable tool for laboratory animal severity assessment.

animal behavior and cognition↗