A spin-flip study of the diradical isomers of pyrrole, furan, and thiophene.

Heteroaromatic species are commonly found in complex gaseous mixtures, from tobacco smoke to petroleum and asphaltene combustion products. At high temperatures, C-H bond rupture produces various dehydro radical isomers. We have used the spin-flip formulation of equation-of-motion coupled cluster theory with single and double substitutions (EOM-SF-CCSD) to characterize the energies and wave functions of the lowest lying singlet and triplet states of the diradical (2,3), (2,4), (2,5), and (3,4) di-dehydro isomers of pyrrole, furan, and thiophene. In all cases, these diradicals are minima on the broken-symmetry ωB97X-D/cc-pVDZ potential energy surface. In most cases, the diradical geometries distort to enhance through-space or through-bond coupling in the singlet states and to avoid Coulombic or exchange repulsion in the triplet states. EOM-SF-CCSD results indicate that all diradical isomers are two-configurational, closed shell singlet states. The only exceptions to this are for (2,3) and (2,4) thiophene and (2,3) pyrrole, which each contain more than two configurations. In all cases, the leading term in the multiconfigurational diradical wave function doubly occupies the symmetric radical σ orbital, indicative of either through-space or 1,3 through-bond coupling. We utilized the nucleus-independent chemical shift (NICS) approach to qualitatively assess aromaticity and find that this property varies and may be related to the energetic splittings in these diradical isomers.

vivoBodySeg: Machine learning-based analysis of C. elegans immobilized in vivoChip for automated developmental toxicity testing.

Developmental toxicity (DevTox) tests evaluate the adverse effects of chemical exposures on an organism's development. While large animal tests are currently heavily relied on, the development of new approach methodologies (NAMs) is encouraging industries and regulatory agencies to evaluate these novel assays. Several practical advantages have made C. elegansa useful model for rapid toxicity testing and studying developmental biology. Although the potential to study DevTox is promising, current low-resolution and labor-intensive methodologies prohibit the use of C. elegans for sub-lethal DevTox studies at high throughputs. With the recent availability of a large-scale microfluidic device, vivoChip, we can now rapidly collect 3D high-resolution images of ~ 1,000 C. elegans from 24 different populations. In this paper, we demonstrate DevTox studies using a 2.5D U-Net architecture (vivoBodySeg) that can precisely segment C. elegans in images obtained from vivoChip devices, achieving an average Dice score of 97.80. The fully automated platform can analyze 36 GB data from each device to phenotype multiple body parameters within 35 min on a desktop PC at speeds ~ 140x faster than the manual analysis. Highly reproducible DevTox parameters (4-8% CV) and additional autofluorescence-based phenotypes allow us to assess the toxicity of chemicals with high statistical power.

Standard Quality Characteristics and Efficacy of a New Third-Generation Antivenom Developed in Colombia Covering Micrurus spp. Venoms.

In Colombia, Micrurus snakebites are classified as severe according to the national clinical care guidelines and must be treated with specific antivenoms. Unfortunately, these types of antivenoms are scarce in certain areas of the country and are currently reported as an unavailable vital medicine. To address this issue, La Universidad de Antioquia, through its spin-off Tech Life Saving, is leading a project to develop third-generation polyvalent freeze-dried antivenom. The goal is to ensure access to this therapy, especially in rural and dispersed areas. This project aims to evaluate the physicochemical and preclinical parameters (standard quality characteristics) of a lab-scale anti-elapid antivenom batch. The antivenom is challenged against the venoms of several Micrurus species, including M. mipartitus, M. dumerilii, M. ancoralis, M. dissoleucus, M. lemniscatus, M. medemi, M. spixii, M. surinamensis, and M. isozonus, following the standard quality characteristics set by the World Health Organization (WHO). The antivenom demonstrates an appearance consistent with standards, 100% solubility within 4 min and 25 s, an extractable volume of 10.39 mL, a pH of 6.04, an albumin concentration of 0.377 mg/mL (equivalent to 1.22% of total protein), and a protein concentration of 30.97 mg/mL. Importantly, it maintains full integrity of its F(ab')2 fragments and exhibits purity over 98.5%. Furthermore, in mice toxicity evaluations, doses up to 15 mg/mouse show no toxic effects. The antivenom also demonstrates a significant recognition pattern against Micrurus venoms rich in phospholipase A2 (PLA2) content, as observed in M. dumerilii, M. dissoleucus, and M. isozonus. The effective dose 50 (ED50) indicates that a single vial (10 mL) can neutralize 2.33 mg of M. mipartitus venom and 3.99 mg of M. dumerilii venom. This new anti-elapid third-generation polyvalent and freeze-dried antivenom meets the physicochemical parameters set by the WHO and the regulators in Colombia. It demonstrates significant efficacy in neutralizing the venom of the most epidemiologically important Micrurus species in Colombia. Additionally, it recognizes seven other species of Micrurus venom with a higher affinity for venoms exhibiting PLA2 toxins. Fulfilling these parameters represents the first step toward proposing a new pharmacological alternative for treating snakebites in Colombia, particularly in dispersed rural areas, given that this antivenom is formulated as a freeze-dried product.

Multiplexable and Scalable Aqueous Synthesis Platform for Oleate-Based, Bilayer-Coated Gold Nanoparticles.

Despite gold-based nanomaterials having a unique role in nanomedicine, among other fields, synthesis limitations relating to reaction scale-up and control result in prohibitively high gold nanoparticle costs. In this work, a new preparation procedure for lipid bilayer-coated gold nanoparticles in water is presented, using sodium oleate as reductant and capping agent. The seed-free synthesis not only allows for size precision (8-30 nm) but also remarkable particle concentration (10 mm Au). These reaction efficiencies allow for multiplexing and reaction standardization in 96-well plates using conventional thermocyclers, in addition to simple particle purification via microcentrifugation. Such a multiplexing approach also enables detailed spectroscopic investigation of the nonlinear growth process and dynamic sodium oleate/oleic acid self-assembly. In addition to scalability (at gram-level), resulting gold nanoparticles are stable at physiological pH, in common cell culture media, and are autoclavable. To demonstrate the versatility and applicability of the reported method, a robust ligand exchange with thiolated polyethylene glycol analogues is also presented.

Variations on the Bergman Cyclization Theme: Electrocyclizations of Ionic Penta-, Hepta-, and Octadiynes.

The Bergman cyclization of (Z)-hexa-3-ene-1,5-diyne to form the aromatic diradical p-benzyne has garnered attention as a potential antitumor agent due to its relatively low cyclization barrier and the stability of the resulting diradical. Here, we present a theoretical investigation of several ionic extensions of the fundamental Bergman cyclization: electrocyclizations of the penta-1,4-diyne anion, hepta-1,6-diyne cation, and octa-1,7-diyne dication, leveraging the spin-flip formulation of the equation-of-motion coupled cluster theory with single and double substitutions (EOM-SF-CCSD). Though the penta-1,4-diyne anion exhibits a large cyclization barrier of +66 kcal mol-1, cyclization of both the hepta-1,6-diyne cation and octa-1,7-diyne dication along a previously unreported triplet pathway requires relatively low energy. We also identified the presence of significant aromaticity in the triplet diradical products of these two cationic cyclizations.

Effect of dietary garlic (Allium sativum) on the zootechnical performance and health indicators of aquatic animals: A mini-review.

Considerable efforts have been made by modern aquaculture to mitigate the environmental damages caused by its practices while also attempting to improve the quality of the aquatic organisms by promoting alternatives, such as the use of natural products, like garlic (Allium sativum), and instead of chemical agents. Garlic has multiple properties, including antifungal, antibacterial, antiviral, antitoxic, and anticancer effects. In fish, the antiparasitic activity of garlic is one of the most reported effects in the literature, mainly using immersion baths for aquatic organisms. Using garlic also has an antimicrobial effect on the culture of aquatic organisms. Therefore, this review focuses on the impact of garlic on the health and production of aquatic organisms.

In Vitro-Based Production of Virus-Tested Babaco (Vasconcellea x heilbornii, syn. Carica pentagona) in Ecuador: An Integrated Approach to an Endangered Crop.

Babaco (Vasconcellea x heilbornii), a fruit-bearing vegetatively propagated crop native to Ecuador, is appreciated for its distinctive flavor and nutritional properties. The aim of this research was to determine a functional protocol for tissue culture propagation of virus-free babaco plants including in vitro establishment, multiplication, rooting, and acclimation. First, symptomless babaco plants from a single commercial nursery were analyzed for virus detection and cared for using different disinfection treatments in the greenhouse to reduce contamination during the in vitro establishing step, and three cytokinins, 6-(γ,γ-Dimethylallylamino) purine (2IP), 6-Benzylaminopurine (BAP), and Thidiazuron (TDZ), were used to determine the best hormone for multiplication. The best treatment for plant disinfection was the weekly application of copper sulfate at the greenhouse and a laboratory disinfection using ethanol (EtOH) (70%), Clorox (2%), and a solution of povidone iodine (2.5%), with an 80% survival during in vitro plant establishment. TDZ showed a better multiplication rate when compared with other hormones, and 70% of the rooted plants were successfully acclimated at the greenhouse. Generated plants were virus-free when tested against babaco mosaic virus (BabMV) and papaya ringspot virus (PRSV), two of the most important viruses that can affect babaco. An efficient protocol to produce virus-free babaco plants was elaborated with an integrated use of viral diagnostic tools to ensure the production of healthy start material to farmers.

The addition of Tirofiban infusión to heparin for intraoperative heparin resistance associated with Marfan Syndrome / Adición de una infusión de Tirofiban a heparina en caso de resistencia intraoperatoria a la heparina asociada al Síndrome de Marfan

Abstract Marfan syndrome classically presents with aortic root aneurysms. Aortic ectasia causes diverse blood flow alterations, influencing the behavior of coagulation factors and platelet activity. Heparin resistance has also been reported associated with Marfan Syndrome in a small number of patients, probably due to antithrombin III (ATIII) deficiency or various mutations. The ascending aorta and the aortic valve are replaced with prosthetic material during Bentall- de Bonno procedures. Resistance to anticoagulation during extracorporeal circulation, represents a significant challenge for both anesthesiologists and the surgical team. Resistance to heparin was observed in a patient with Marfan syndrome undergoing a Bentall procedure. ATIII concentrate was not available, and Activated Coagulation Time did not increase despite high doses of heparin. An alternate anticoagulation approach was used successfully.

Resumen El síndrome de Marfan clásicamente se presenta con aneurismas de la raíz de la aorta. La ectasia aórtica produce alteraciones en el flujo sanguíneo que influyen sobre el comportamiento de los factores de la coagulación y la actividad de las plaquetas. También se ha reportado resistencia a la heparina asociada al Síndrome de Marfan en un menor número de pacientes, probablemente debido a deficiencia de antitrombina III (ATIII) o a diversas mutaciones. La aorta ascendente y la válvula aórtica se reemplazan con material prostético en los procedimientos Bentall- de Bonno. La resistencia a la anticoagulación durante circulación extracorpórea significa un enorme desafío tanto para los anestesiólogos, como para el equipo quirúrgico. Se observó resistencia a la heparina en un paciente con Síndrome de Marfan sometido a un procedimiento de Bentall. No había disponibilidad de concentrado ATIII y no aumentó el Tiempo de Coagulación Activada a pesar de las elevadas dosis de heparina. Se utilizó exitosamente un abordaje alterno de anticoagulación.

Epidemiology of Snake Bites Linked with the Antivenoms Production in Colombia 2008-2020: Produced Vials Do Not Meet the Needs.

Introduction: Snakebite envenomation is a public health event of mandatory reporting in Colombia. It is considered a medical emergency in which the government must guarantee antivenom availability. We describe snakebite epidemiological figures in Colombia between 2008 and 2020 and correlate them with antivenom manufacturing figures to determine rate coverage and the need for antivenom. Methods: We performed an ecological study based on secondary official figures from the National Health Institute, the National Institute for Surveillance of Medicines and Foods, the National Administrative Department of Statistics and the Ministry of Health and Social Protection. Absolute and relative frequencies were calculated with 95% confidence intervals, position measurements, dispersion and central tendency. Results: Through our research, we revealed that in the last 13 years (2008-2020), there were an average of 4467 annual snakebite envenomation cases affecting all the departments in Colombia. Antioquia reported the highest number of snakebites with 647 (95% CI 588-706) cases per year. The population incidence per 100,000 inhabitants was 9.5; the highest rates were found in Vaupés at 116.1 and Guaviare at 79.24. During the last seven years (2014-2020) Colombia produced an average of 21,104 antivenom vials per year, while the annual demand for antivenom is estimated at 54,440 units needed to guarantee access. Discussion: Colombia does not produce sufficient vials to cover their needs, and this is why only 74.4% of accidents (out of the 92% not classified as dry bites) were treated, and even 9.7% of the severe accidents did not receive the specific treatment (8% of the victims were classified as dry bites). Figures support the regular antivenom shortages declared by the Ministry of Health and Social Protection in the last 13 years (11 health emergency declarations). New efforts are needed to: 1) boost the production of GMP-based high-quality antivenom, that covers the national needs and is made availability, 2) a better estimation method to calculate the need for antivenom in Colombia, and 3) implementation of production-distribution chains guaranteeing access in remote communities.

Characterization of a Lab-Scale Process to Produce Whole IgG Antivenom Covering Scorpion Stings by Genus Tityus and Centruroides of Colombia.

Scorpion stings are a public health event in Colombia lacking official epidemiological data, and are considered a medical emergency. Despite the two local producers of antivenoms, neither of them is currently manufacturing scorpion antivenoms. We present the characterization of a lab-scale process to produce the first specific scorpion antivenom for Colombia, formulated to cover scorpion stings produced by Tityus pachyurus, Tityus asthenes, Tityus fuhrmanii, Centruroides spp. To do so, rabbits were immunized by subcutaneous injection with each venom using an immunization program of 3 months. After each rabbit reached the required IgG concentration, rabbits were bled, and plasma was separated by decantation under refrigeration. Immunoglobulins were purified from each hyperimmune plasma using a methodology including precipitation with ammonium sulfate, thermocoagulation, and purification through an ultrafiltration process using a ready-to-use and reusable laboratory crossflow tangential cassette with a polyethersulfone membrane. Each hyperimmune plasma was processed by being separated and freeze-dried at the end of the process. Rabbits were able to produce specific IgG antibodies recognizing the respective immunization venom; even an in vitro interspecies cross-recognition was detected. The separation and purification processes allowed us to obtain IgG products without considerable contaminants (except for albumin). The process was characterized, and critical stages were identified.

A specialized tyrosine-based endocytosis signal in MR1 controls antigen presentation to MAIT cells.

MR1 is a highly conserved microbial immune-detection system in mammals. It captures vitamin B-related metabolite antigens from diverse microbes and presents them at the cell surface to stimulate MR1-restricted lymphocytes including mucosal-associated invariant T (MAIT) cells. MR1 presentation and MAIT cell recognition mediate homeostasis through host defense and tissue repair. The cellular mechanisms regulating MR1 cell surface expression are critical to its function and MAIT cell recognition, yet they are poorly defined. Here, we report that human MR1 is equipped with a tyrosine-based motif in its cytoplasmic domain that mediates low affinity binding with the endocytic adaptor protein 2 (AP2) complex. This interaction controls the kinetics of MR1 internalization from the cell surface and minimizes recycling. We propose MR1 uses AP2 endocytosis to define the duration of antigen presentation to MAIT cells and the detection of a microbial metabolic signature by the immune system.

Prescripción de protectores gástricos en pacientes reumatológicos: análisis desde Consulta Externa de Gastroenterología / Prescription of gastric protectors in rheumatological patients: Analysis from a gastroenterology outpatient clinic

Introducción: Los antinflamatorios no esteroideos son los medicamentos más recetados por reumatólogos y traumatólogos. Pero a pesar de tener una eficacia similar para controlar la inflamación y el dolor, los diferentes antinflamatorios no esteroideos disponibles presentan variabilidad en su perfil de seguridad. Objetivo: Brindar una panorámica sobre la prescripción de protectores gástricos en pacientes reumatológicos, en dos centros hospitalarios, desde una perspectiva gastroenterológica. Métodos: La investigación se inscribe en el paradigma cuantitativo con un estudio observacional. Se conformaron dos grupos de pacientes, uno de ellos provenientes del hospital A y el segundo grupo pertenecía al hospital B. Discusión: Los gastroprotectores se han convertido en los fármacos de mayor demanda en las farmacias comunitarias de Ecuador, y los más prescritos son los inhibidores de la bomba de protones y en menor frecuencia los antihistamínicos H2. Respecto a los gastroprotectores más frecuentemente prescritos, según nuestro estudio, estos valores podrían obedecer a la disponibilidad y los costos de la famotidina y el omeprazol con respecto a otros medicamentos de probada eficacia (ansoprazol, pantoprazol, rabeprazol y ranitidina). Conclusiones: Durante los últimos años, el uso de los fármacos gastroprotectores en América Latina ha experimentado un importante desarrollo, con la observancia de normas y guías clínicas de manejo de casos que ofrecen recomendaciones importantes al respecto. Por tanto, desde una perspectiva gastroenterológica, para tener éxito, es indispensable procurar un conocimiento de estos aportes y evidencias científicas(AU)

Introduction: Nonsteroidal anti-inflammatory drugs are the most prescribed medications by rheumatologists and traumatologists. However, despite having similar efficacy in controlling inflammation and pain, the different available nonsteroidal anti-inflammatory drugs show variability in their safety profile. Objective: To provide an overview of the prescription of gastric protectors in rheumatological patients, in two hospital centers, from a gastroenterological perspective. Methods: The research is part of the quantitative paradigm with an observational study. Two groups of patients were formed, one of them from hospital A and the second group belonged to hospital B. Discussion: Gastroprotectors have become the drugs in greatest demand in community pharmacies in Ecuador, the most prescribed being Proton Pump Inhibitors (IBPS) and, to a lesser extent, H2 antihistamines (anti-H2). Regarding the most frequently prescribed gastroprotectors, according to our study, these values ​​could be due to the availability and costs of famotidine and omeprazole compared to other drugs with proven effectiveness, such as ansoprazol, pantoprazole, rabeprazole and ranitidine. Conclusions: In recent years, the use of gastroprotective drugs in Latin America has undergone significant development, with the observance of clinical case management norms and guidelines that offer important recommendations in this regard. Therefore, from a gastroenterological perspective, to be successful, it is essential to seek knowledge of these contributions and scientific evidence(AU)

Improving the Annotation of the Venom Gland Transcriptome of Pamphobeteus verdolaga, Prospecting Novel Bioactive Peptides.

Spider venoms constitute a trove of novel peptides with biotechnological interest. Paucity of next-generation-sequencing (NGS) data generation has led to a description of less than 1% of these peptides. Increasing evidence supports the underestimation of the assembled genes a single transcriptome assembler can predict. Here, the transcriptome of the venom gland of the spider Pamphobeteus verdolaga was re-assembled, using three free access algorithms, Trinity, SOAPdenovo-Trans, and SPAdes, to obtain a more complete annotation. Assembler's performance was evaluated by contig number, N50, read representation on the assembly, and BUSCO's terms retrieval against the arthropod dataset. Out of all the assembled sequences with all software, 39.26% were common between the three assemblers, and 27.88% were uniquely assembled by Trinity, while 27.65% were uniquely assembled by SPAdes. The non-redundant merging of all three assemblies' output permitted the annotation of 9232 sequences, which was 23% more when compared to each software and 28% more when compared to the previous P. verdolaga annotation; moreover, the description of 65 novel theraphotoxins was possible. In the generation of data for non-model organisms, as well as in the search for novel peptides with biotechnological interest, it is highly recommended to employ at least two different transcriptome assemblers.

A trail of dark-matter-free galaxies from a bullet-dwarf collision.

The ultra-diffuse galaxies DF2 and DF4 in the NGC 1052 group share several unusual properties: they both have large sizes1, rich populations of overluminous and large globular clusters2-6, and very low velocity dispersions that indicate little or no dark matter7-10. It has been suggested that these galaxies were formed in the aftermath of high-velocity collisions of gas-rich galaxies11-13, events that resemble the collision that created the bullet cluster14 but on much smaller scales. The gas separates from the dark matter in the collision and subsequent star formation leads to the formation of one or more dark-matter-free galaxies12. Here we show that the present-day line-of-sight distances and radial velocities of DF2 and DF4 are consistent with their joint formation in the aftermath of a single bullet-dwarf collision, around eight billion years ago. Moreover, we find that DF2 and DF4 are part of an apparent linear substructure of seven to eleven large, low-luminosity objects. We propose that these all originated in the same event, forming a trail of dark-matter-free galaxies that is roughly more than two megaparsecs long and angled 7° ± 2° from the line of sight. We also tentatively identify the highly dark-matter-dominated remnants of the two progenitor galaxies that are expected11 at the leading edges of the trail.

Linking toxicity and predation in a venomous arthropod: the case of Tityus fuhrmanni (Scorpiones: Buthidae), a generalist predator scorpion.

BACKGROUND: Scorpions are arachnids that have a generalist diet, which use venom to subdue their prey. The study of their trophic ecology and capture behavior is still limited compared to other organisms, and aspects such as trophic specialization in this group have been little explored. METHODS: In order to determine the relationship between feeding behavior and venom toxicity in the scorpion species Tityus fuhrmanni, 33 specimens were offered prey with different morphologies and defense mechanisms: spiders, cockroaches and crickets. In each of the experiments we recorded the following aspects: acceptance rate, immobilization time and the number of capture attempts. The median lethal dose of T. fuhrmanni venom against the three different types of prey was also evaluated. RESULTS: We found that this species does not have a marked difference in acceptance for any of the evaluated prey, but the number of capture attempts of spiders is higher when compared to the other types of prey. The immobilization time is shorter in spiders compared to other prey and the LD50 was higher for cockroaches. CONCLUSIONS: These results indicate that T. fuhrmanni is a scorpion with a generalist diet, has a venom with a different potency among prey and is capable of discriminating between prey types and employing distinct strategies to subdue them.

Diagnostic and Prognostic Roles of Serum Interleukin-6 Levels in Patients with Uveitis.

PURPOSE: To examine the diagnostic and prognostic roles of serum interleukin-6 levels in patients with uveitis. METHODS: This was a retrospective observational case series. Demographic and clinical characteristics were compared between Group One (sixty patients) with normal serum IL-6 levels and Group Two (twenty patients) with high serum interleukin-6 levels. RESULTS: Mean IL-6 level was 1.77 ± 0.97 pg/ml and 10.2 ± 9.7 pg/ml in Group One and Group Two respectively. Age, presence of systemic disease, and mean number of flare-ups were statistically significant (p = .015, p = .000, p = .03, respectively). Multivariate analysis was performed on variables that were statistically significant in univariate analysis and showed that three variables had significant correlation with IL-6 levels in both groups: systemic disease (OR = 10.83, p < .001), Age (OR = 0.95, p = .03) and number of flare-ups (OR = 2.9, p = .02). CONCLUSION: Serum IL-6 levels can provide diagnostic and prognostic information in regard to the course of disease and its treatment.

First evidence of regional migration of the copper shark Carcharhinus brachyurus (Günther, 1870) in the Southwest Atlantic.

Regional migration of the copper shark Carcharhinus brachyurus was recorded for the first time in the Southwest Atlantic (SWA) from Argentina (latitude: -38.1037, longitude: -57.5371) to Brazil (latitude: -20.6833, longitude: -40.2846) as a result of a citizen science tagging project. The recaptured specimen was a female (103 kg weight), with 18 developing embryos within the uterus. The total distance was at least 2566 km, and it is the longest ever recorded for the species. Furthermore, it extends its northern distribution in the SWA.

Acquired Vitelliform-Like Lesion in Uveitis: A case-series.

PURPOSE: To study acquired vitelliform-like lesions (AVLL) and their diagnostic and prognostic values in uveitis. PATIENTS AND METHODS: This was a retrospective case series. The clinical course, diagnostic value, and prognostic significance of AVLL were compared between uveitic patients with AVLL and uveitic patients without AVLL. RESULTS: Twelve patients (21 eyes) with both uveitis and AVLL (study group) and thirteen patients (24 eyes) without AVLL (control group) were included in the study. Macular leakage (p = .005), the presence of vasculitis (p = .01), the presence of active choroiditis (p = .01), and the presence of CME on OCT (p = .008) were significantly higher in the AVLL group compared to the control group. Best-corrected visual acuity was significantly lower at presentation (p < .001) and the last follow-up visit (p = .014) in the AVLL group. CONCLUSION: The presence of acquired vitelliform-like lesion can have both a diagnostic (uveitis as a differential diagnosis) and prognostic value in patients with different types of uveitis.

Linking toxicity and predation in a venomous arthropod: the case of Tityus fuhrmanni (Scorpiones: Buthidae), a generalist predator scorpion

Abstract Background: Scorpions are arachnids that have a generalist diet, which use venom to subdue their prey. The study of their trophic ecology and capture behavior is still limited compared to other organisms, and aspects such as trophic specialization in this group have been little explored. Methods: In order to determine the relationship between feeding behavior and venom toxicity in the scorpion species Tityus fuhrmanni, 33 specimens were offered prey with different morphologies and defense mechanisms: spiders, cockroaches and crickets. In each of the experiments we recorded the following aspects: acceptance rate, immobilization time and the number of capture attempts. The median lethal dose of T. fuhrmanni venom against the three different types of prey was also evaluated. Results: We found that this species does not have a marked difference in acceptance for any of the evaluated prey, but the number of capture attempts of spiders is higher when compared to the other types of prey. The immobilization time is shorter in spiders compared to other prey and the LD50 was higher for cockroaches. Conclusions: These results indicate that T. fuhrmanni is a scorpion with a generalist diet, has a venom with a different potency among prey and is capable of discriminating between prey types and employing distinct strategies to subdue them.

Linking toxicity and predation in a venomous arthropod: the case of Tityus fuhrmanni (Scorpiones: Buthidae), a generalist predator scorpion

Background: Scorpions are arachnids that have a generalist diet, which use venom to subdue their prey. The study of their trophic ecology and capture behavior is still limited compared to other organisms, and aspects such as trophic specialization in this group have been little explored. Methods: In order to determine the relationship between feeding behavior and venom toxicity in the scorpion species Tityus fuhrmanni, 33 specimens were offered prey with different morphologies and defense mechanisms: spiders, cockroaches and crickets. In each of the experiments we recorded the following aspects: acceptance rate, immobilization time and the number of capture attempts. The median lethal dose of T. fuhrmanni venom against the three different types of prey was also evaluated. Results: We found that this species does not have a marked difference in acceptance for any of the evaluated prey, but the number of capture attempts of spiders is higher when compared to the other types of prey. The immobilization time is shorter in spiders compared to other prey and the LD50 was higher for cockroaches. Conclusions: These results indicate that T. fuhrmanni is a scorpion with a generalist diet, has a venom with a different potency among prey and is capable of discriminating between prey types and employing distinct strategies to subdue them.(AU)