Antimicrobial compounds from natural sources

Universidade Federal de São Paulo, UNIFESP, Dept Farmacol, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Med, São Paulo, BrazilButantan Inst, Ctr Toxinol Aplicada, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Farmacol, São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Med, São Paulo, BrazilWeb of Scienc

Presynaptic Activity of an Isolated Fraction from Rhinella schneideri Poison

Purpose: Rhinella schneideri is a toad found in many regions of the South America. The poison of the glands has cardiotoxic effect in animals and neuromuscular effects in mice and avian preparation. The purpose of this work was to identify the toxin responsible for the neuromuscular effect in avian and mice neuromuscular preparation. Methods: The methanolic extract from R. schneideri poison was fractioned by reversed phase HPLC. The purity and molecular mass were determined by LC/MS mass spectrometry. Chick biventer cervicis and mouse phrenic-nerve diaphragm were used as neuromuscular preparations to identify the toxin. Results: The purification resulted in 32 fractions, which 4 of them were active in neuromuscular preparation. The toxin of fraction 20 were chosen for better reproducibility of the whole extract activity and its molecular mass was 730.6 Da. The toxin produced facilitation of the muscle contraction followed by a complete neuromuscular blockade in chick biventer cervicis preparation in 90 min without interfering with the exogenous response to ACh and KCl. The quantal content was increased from 128 ± 13 (control) to 216 ± 44 (after 5 min and sustained until 60 min) in the presence of the toxin. Conclusion: In conclusion, our results demonstrated that the neuromuscular action of the poison of Rhinella schneideri is a multitoxin effect. More, the present work first isolated a 730.6 Da toxin that better represent the whole poison neuromuscular effect, to which is attributed a presynaptic action in avian and mouse neuromuscular preparation

Catálogo Taxonômico da Fauna do Brasil: setting the baseline knowledge on the animal diversity in Brazil

The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others

Immune system in aracnids: chemical structure and biological activity of antimicrobials peptides from Acanthoscurria gomesiana.

Peptídeos antimicrobianos são importantes componentes do sistema imune de vertebrados e invertebrados. Neste trabalho purificamos e caracterizamos quatro moléculas presentes na hemolinfa da aranha Acanthoscurria gomesiana: 1) theraphosinina, peptídeo de 4052,5 Da purificado do plasma, apresenta atividade anti-Micrococcus luteus e não apresenta similaridade com outros peptídeos. A partir dos hemócitos foram purificados: 2) mygalomorphina, um peptídeo de 415,9 Da com atividade anti-Escherichia coli. Sua atividade está relacionada à produção de H2O2 pois é inibida por catalase; 3) gomesina, um peptídeo de 2270,4 Da que apresenta alta similaridade com taquiplesinas e protegrinas. Apresenta amplo espectro de atividade contra bactérias, leveduras, fungos e Leishmania; 4) acanthoscurrina, um peptídeo rico em glicina, que apresenta duas isoformas com 10132,4 e 10249,1Da. Este peptídeo tem atividade contra E. coli e Candida albicans e apresenta grande similaridade com proteinas antifúngicas de insetos e também com proteínas relacionadas com a defesa em plantas.Antimicrobial peptides are important components of the vertebrates and invertebrates immune system. In this work we purified and characterized four molecules from Acanthoscurria gomesiana spider hemolimph: 1) theraphosinin, a 4,052.5 Da peptide purified from plasma with anti-Micrococcus luteus activity. It does not show similarity with any other invertebrate immune peptides. From the hemocytes three peptides have been purified: 2) mygalomorphin, a peptide with 415.9 Da, which shows anti-Escherichia coli activity. This activity is inhibited by catalase, therefore it may be, related to the H2O2 production; 3) gomesin, a peptide with 2,270.4 Da, that shows high similarity with tachyplesins and protegrins. It have large activity spectrum against bacteria, yeast, fungi and Leishmania; 4) acanthoscurrin, a glycine-rich peptide that shows two isoforms of 10,132.4 and 10,249.1 Da. This peptide has activity against E. coli and Candida albicans and shows high similarity with antifungal proteins of insects and plants defense proteins

Hemoglobin Reassembly of Antimicrobial Fragments from the Midgut of Triatoma infestans

Hemoglobin is one of the most important molecules of the human body. Beyond its physiological activity, hemoglobins are able to inhibit the growth of several microorganisms. Since 1999, studies have reported that antimicrobial peptides can be produced by blood-feeding insects through hemoglobin digestion, and it has been reported that Triatoma infestans can generate an antimicrobial fragment from human fibrinopeptide. Thus T. infestans intestinal content was analyzed through Reverse Phase High-Performance Liquid Chromatography (RP-HPLC), the eluted fractions were tested against Micrococcus luteus, Escherichia coli and Staphylococcus aureus, and the active fractions submitted to mass spectrometry. The data obtained were compared to hemoglobin databases to verify the presence of hemoglobin-derived fragments. Ten fractions eluted from chromatography presented antimicrobial activity, and when analyzed through mass spectrometry revealed the presence of 8 murine hemoglobin α-chain fragments and 24 fragments from murine hemoglobin β fragments. Through the compilation of the fragments is possible to obtain over 67% coverage of both sequences. Part of the amino acid sequences corresponds to the sequences already identified on other intestinal contents of arthropods, and are highly conserved between the blood of other wild animals that are the most common intermediate hosts of Chagas’ disease in Brazil and some of the main natural blood source for triatomines

Mating behavior of Sickius longibulbi (Araneae, Theraphosidae, Ischnocolinae), a spider that lacks spermathecae

We describe the mating behavior in the spermatheca-lacking theraphosid species Sickius longibulbi Soares & Camargo 1948. The behavior in captivity of nine pairs of S. longibulbi was videotaped and analyzed. The matting of this species presented an uncommon theraphosid pattern. There is little in the way of overt courtship by the male, the primary behavior seen being the male`s use of legs I and II to touch the female`s first pairs of legs and her chelicerae. Sometimes the male clasped one of the female`s first pairs of legs, bringing her close to him. While the female raised her body, the male clasped her fangs and held her tightly with his legs III wrapped around her prosoma. The male seemed to try to knock the female down, pushing her entire body until she lay on her dorsum. In this phase we observed the male biting the female on the sternum or on the leg joints. When the female fell, the male attempted to position himself at an angle of 90 degrees from the female. These movements appear to demand a lot of energy, particularly because the female is not passive during the mating. Our findings suggest that copulating in this position is, for the male, more successful than adopting other positions because it allows his extremely long palpal bulbs to deposit more sperm in the female oviduct where - since she lacks spermathecae - she retains the sperm. We suggest that the further he reaches into the oviduct, the greater the chance that he will fertilize the female`s eggs.FAPESP[03/12587-4]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP[06/58326-5]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPE

Serrulin: A Glycine-Rich Bioactive Peptide from the Hemolymph of the Yellow Tityus serrulatus Scorpion

Antimicrobial peptides (AMPs) are small molecules, which have a potential use as antibiotic or pharmacological tools. In chelicerate organisms, such as scorpions, these molecules constitute an alternative defense system against microorganisms. The aim of this work was to identify AMPs in the hemolymph of the Tityus serrulatus scorpion. Fractions of plasma and hemocytes were subjected to high-performance liquid chromatography (HPLC) and then analyzed to determine their activity in inhibiting microbial growth. One of the fractions from the hemocytes presents antimicrobial activity against microorganisms, such as Gram-negative and Gram-positive bacteria, fungi, and yeast. These fractions were analyzed by mass spectrometry, and a fragment of 3564 Da. was identified. The peptide was called serrulin, because it is derived from the species T. serrulatus. A comparison of the amino acid sequence of serrulin with databases shows that it has a similarity to the glycine-rich peptides described in Cupienius salai and Acanthoscurria gomesiana (spiders). Furthermore, serrulin has no hemolytic activity against human erythrocytes. While the presence of AMPs in T. serrulatus venom has been described in other works, this is the first work to characterize the presence of these molecules in the hemolymph (hemocytes) of this species and show its potential use as an alternative to conventional antibiotics against different species of microorganisms

Chemosensory discrimination of male age by female Psammodromus algirus lizards based on femoral secretions and feces

Chemical communication plays an essential role in several social and reproductive behaviors of many animals. In lizards, the main sources of semiochemicals are femoral or pre-anal gland secretions and feces. In male lizards Psammodromus algirus, there are age-related differences in the chemical composition of femoral gland secretions and in the reproductive strategies, with older males defending territories and females, while younger males adopting sneak-mating strategies. Females flee more often from mating advances of young males than from those of old males, which are more successful in obtaining matings. This suggests that age discrimination of males may be important for females. We tested here whether females showed differential chemosensory responses to chemical cues (femoral gland secretion and feces) of males of two age classes, and whether females use information from substrate scent marks of males of different ages to select where to stay. We found that females elicited more tongue-flicks to the secretion and feces of old males than to control or secretion and feces of young males. Also, the time spent by females on a scented paper depended on the treatment, suggesting that females tended to spend more time on scent marks made with femoral secretions of old males. Adult females seemed capable to discriminate between young and old males based on chemical cues alone and showed more interest in scents of old males. However, substrate scent marks did not seem to entirely determine site selection by females, suggesting that females might need additional cues to perform the choice. These results can be explained by the different age-dependent reproductive strategies of males, which can affect differentially to females.Financial support was provided by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP 2017/19640‐0) and by the Ministerio de Economía y Competitividad project MINECO CGL2014‐53523‐P