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Abstract Pneumococcal surface protein A (PspA) is an important virulence factor in Streptococcus pneumoniae that binds to lactoferrin and protects the bacterium from the bactericidal action of lactoferricins—cationic peptides released upon lactoferrin proteolysis. The present study investigated if PspA can prevent killing by another cationic peptide, indolicidin. PspA-negative pneumococci were more sensitive to indolicidin-induced killing than bacteria expressing PspA, suggesting that PspA prevents the bactericidal action of indolicidin. Similarly, chemical removal of choline-binding proteins increased sensitivity to indolicidin. The absence of capsule and PspA had an additive effect on pneumococcal killing by the AMP. Furthermore, anti-PspA antibodies enhanced the bactericidal effect of indolicidin on pneumococci, while addition of soluble PspA fragments competitively inhibited indolicidin action. Previous in silico analysis suggests a possible interaction between PspA and indolicidin. Thus, we hypothesize that PspA acts by sequestering indolicidin and preventing it from reaching the bacterial membrane. A specific interaction between PspA and indolicidin was demonstrated by mass spectrometry, confirming that PspA can actively bind to the AMP. These results reinforce the vaccine potential of PspA and suggest a possible mechanism of innate immune evasion employed by pneumococci, which involves binding to cationic peptides and hindering their ability to damage the bacterial membranes.

Abstract Spiders are important predators of insects and their venoms play an essential role in prey capture. Spider venoms have several potential applications as pharmaceutical compounds and insecticides. However, transcriptomic and proteomic analyses of the digestive system (DS) of spiders show that DS is also a rich source of new peptidase inhibitor molecules. Biochemical, transcriptomic and proteomic data of crude DS extracts show the presence of molecules with peptidase inhibitor potential in the spider Nephilingis cruentata. Therefore, the aims of this work were to isolate and characterize molecules with trypsin inhibitory activity. The DS of fasting adult females was homogenized under acidic conditions and subjected to heat treatment. After that, samples were submitted to ion exchange batch and high-performance reverse-phase chromatography. The fractions with trypsin inhibitory activity were confirmed by mass spectrometry, identifying six molecules with inhibitory potential. The inhibitor NcTI (Nephilingis cruentata trypsin inhibitor) was kinetically characterized, showing a KD value of 30.25 nM ± 8.13. Analysis of the tertiary structure by molecular modeling using Alpha-Fold2 indicates that the inhibitor NcTI structurally belongs to the MIT1-like atracotoxin family. This is the first time that a serine peptidase inhibitory function is attributed to this structural family and the inhibitor reactive site residue is identified. Sequence analysis indicates that these molecules may be present in the DS of other spiders and could be associated to the inactivation of prey trypsin (serine peptidase) ingested by the spiders.

Sea anemones are known to produce a diverse array of toxins with different cysteine-rich peptide scaffolds in their venoms. The serine peptidase inhibitors, specifically Kunitz inhibitors, are an important toxin family that is believed to function as defensive peptides, as well as prevent proteolysis of other secreted anemone toxins. In this study, we isolated three serine peptidase inhibitors named Anthopleura cascaia peptide inhibitors I, II, and III (ACPI-I, ACPI-II, and ACPI-III) from the venom of the endemic Brazilian sea anemone A. cascaia. The venom was fractionated using RP-HPLC, and the inhibitory activity of these fractions against trypsin was determined and found to range from 59% to 93%. The spatial distribution of the anemone peptides throughout A. cascaia was observed using mass spectrometry imaging. The inhibitory peptides were found to be present in the tentacles, pedal disc, and mesenterial filaments. We suggest that the three inhibitors observed during this study belong to the venom Kunitz toxin family on the basis of their similarity to PI-actitoxin-aeq3a-like and the identification of amino acid residues that correspond to a serine peptidase binding site. Our findings expand our understanding of the diversity of toxins present in sea anemone venom and shed light on their potential role in protecting other venom components from proteolysis.

Abstract Background Naja mandalayensis is a spitting cobra from Myanmar. To the best of our knowledge, no studies on this venom composition have been conducted so far. On the other hand, few envenomation descriptions state that it elicits mainly local inflammation in the victims’ eyes, the preferred target of this spiting cobra. Symptoms would typically include burning and painful sensation, conjunctivitis, edema and temporary loss of vision. Methods We have performed a liquid-chromatography (C18-RP-HPLC) mass spectrometry (ESI-IT-TOF/MS) based approach in order to biochemically characterize N. mandalayensis venom. Results A wide variety of three-finger toxins (cardiotoxins) and metallopeptidases were detected. Less abundant, but still representative, were cysteine-rich secretory proteins, L-amino-acid oxidases, phospholipases A2, venom 5'-nucleotidase and a serine peptidase inhibitor. Other proteins were present, but were detected in a relatively small concentration. Conclusion The present study set the basis for a better comprehension of the envenomation from a molecular perspective and, by increasing the interest and information available for this species, allows future venom comparisons among cobras and their diverse venom proteins.

Among the vast repertoire of animal toxins and venoms selected by nature and evolution, mankind opted to devote its scientific attention—during the last century—to a restricted group of animals, leaving a myriad of toxic creatures aside. There are several underlying and justifiable reasons for this, which include dealing with the public health problems caused by envenoming by such animals. However, these studies became saturated and gave rise to a whole group of animals that become neglected regarding their venoms and secretions. This repertoire of unexplored toxins and venoms bears biotechnological potential, including the development of new technologies, therapeutic agents and diagnostic tools and must, therefore, be assessed. In this review, we will approach such topics through an interconnected historical and scientific perspective that will bring up the major discoveries and innovations in toxinology, achieved by researchers from the Butantan Institute and others, and describe some of the major research outcomes from the study of these neglected animals.

Abstract The propolis produced by stingless bees of the tribe Meliponini is a viscous product that contains the resin collected from buds, leaves and plant exudates, mixed with salivary secretions, wax and soil. The species Scaptotrigona aff. postica (Latreille, 1807), (Hymenoptera, Apidae, Meliponinae) popularly known as “tubi” in Maranhão State, Brazil, does not mix soil to produce its propolis. The propolis from S. postica harvested in Barra do Corda, Maranhão State, is popularly used in the treatment of wounds and respiratory illnesses. The hydroalcoholic extract of this propolis, rich in flavone-6,8-di-C-glycosides (vicenin-2 and schaftoside), pyrrolizidine alkaloids derived from retronecine, catechin and caffeoylquinic acid derivatives exhibited antiviral activity against the herpes simplex and rubella viruses. The aim of this study was to increase knowledge about the chemical composition of the S. postica propolis by analyzing non-polar extracts obtained using hexane and chloroform as the solvents, by GC-EI-MS. A total of 15 constituents were identified comparing their respective mass spectral data with those available in the NIST data bases and those reported in the literature. The main constituents detected were the phenolic lipids, known as cardanols, 3-(4,7-heptadecadienyl) phenol (5), 3-(10-heptadecenyl) phenol (7), 3-heptadecylphenol (9) and 3-pentadecyl phenol or hydrocardanol (13), which predominated in the hexane extract, while the predominant constituents in the chloroform extract were 3-pentadecyl phenol or hydrocardanol (13) and 3-(8-pentadecenyl) phenol (12). The antioxidant, antitumoral, antifeedant, cytotoxic, anticarcinogenic, antiproliferative, antimicrobial, antileishmanial and larvicidal activities of the cardanols have been demonstrated in many studies.

A exigência por alimentos com composição nutricional balanceada e que possam oferecer benefícios adicionais á saúde é manifestada pelos consumidores atuais. A utilização de culturas probióticas pela indústria de laticínios vem ganhando destaque, com o lançamento, no mercado, de uma serie de produtos funcionais. Os probióticos são microrganismos que interferem positivamente no organismo de quem os ingere, por mero do equilíbrio da microbiota intestinal e das funções fisiológicas do trato intestinal humano. Neste trabalho, objetivou-se acompanhar a viabilidade de Lactobacillus paracasei, durante a produção e o armazenamento de mousse sabor manga além de avaliar a preferência do consumidor quanto à sua textura. Foram produzidas mousses probióticas com adição de goma xantana. de goma Locusta (LBG) e ccmbinando-se as duas. A viabilidade de microrganismo probiótico foi avaliada a cada sete dias, durante 21 dias de armazenamento refrigerado, em ágar MRS acidificado. Também foram avaliados os parâmetros pH e acidez titulável. nos mesmos dias de amostragem. A composição centesimal foi analisada no dia seguinte á produção, a fim de se caracterizar o produto. Avaliaram-se, também, as três amostras quanto á textura preferida, utilizando-se teste sensorial. Todo o experimente foi repetido três vezes. A mousse de manga mostrou ser uni excelente veículo para a incorporação de L. paracasei, e os diferentes hidrocolóides utilizados não interferiram em sua viabilidade. Além disso, a formulação contendo somente a goma LBG foi preferida pelos consumidores, na análise sensorial, quando comparada com a mousse contendo os dois hidrocolóides. Não foi observada diferença estatística significativa (p>0,05) entre as outras formulações, utilizando-se teste de preferência.

Pneumococcal surface protein A (PspA) is an important virulence factor in Streptococcus pneumoniae that binds to lactoferrin and protects the bacterium from the bactericidal action of lactoferricins—cationic peptides released upon lactoferrin proteolysis. The present study investigated if PspA can prevent killing by another cationic peptide, indolicidin. PspA-negative pneumococci were more sensitive to indolicidin-induced killing than bacteria expressing PspA, suggesting that PspA prevents the bactericidal action of indolicidin. Similarly, chemical removal of choline-binding proteins increased sensitivity to indolicidin. The absence of capsule and PspA had an additive effect on pneumococcal killing by the AMP. Furthermore, anti-PspA antibodies enhanced the bactericidal effect of indolicidin on pneumococci, while addition of soluble PspA fragments competitively inhibited indolicidin action. Previous in silico analysis suggests a possible interaction between PspA and indolicidin. Thus, we hypothesize that PspA acts by sequestering indolicidin and preventing it from reaching the bacterial membrane. A specific interaction between PspA and indolicidin was demonstrated by mass spectrometry, confirming that PspA can actively bind to the AMP. These results reinforce the vaccine potential of PspA and suggest a possible mechanism of innate immune evasion employed by pneumococci, which involves binding to cationic peptides and hindering their ability to damage the bacterial membranes. [ABSTRACT FROM AUTHOR]

Sea anemones are known to produce a diverse array of toxins with different cysteine-rich peptide scaffolds in their venoms. The serine peptidase inhibitors, specifically Kunitz inhibitors, are an important toxin family that is believed to function as defensive peptides, as well as prevent proteolysis of other secreted anemone toxins. In this study, we isolated three serine peptidase inhibitors named Anthopleura cascaia peptide inhibitors I, II, and III (ACPI-I, ACPI-II, and ACPI-III) from the venom of the endemic Brazilian sea anemone A. cascaia. The venom was fractionated using RP-HPLC, and the inhibitory activity of these fractions against trypsin was determined and found to range from 59% to 93%. The spatial distribution of the anemone peptides throughout A. cascaia was observed using mass spectrometry imaging. The inhibitory peptides were found to be present in the tentacles, pedal disc, and mesenterial filaments. We suggest that the three inhibitors observed during this study belong to the venom Kunitz toxin family on the basis of their similarity to PI-actitoxin-aeq3a-like and the identification of amino acid residues that correspond to a serine peptidase binding site. Our findings expand our understanding of the diversity of toxins present in sea anemone venom and shed light on their potential role in protecting other venom components from proteolysis. [ABSTRACT FROM AUTHOR]

Spiders are important predators of insects and their venoms play an essential role in prey capture. Spider venoms have several potential applications as pharmaceutical compounds and insecticides. However, transcriptomic and proteomic analyses of the digestive system (DS) of spiders show that DS is also a rich source of new peptidase inhibitor molecules. Biochemical, transcriptomic and proteomic data of crude DS extracts show the presence of molecules with peptidase inhibitor potential in the spider Nephilingis cruentata. Therefore, the aims of this work were to isolate and characterize molecules with trypsin inhibitory activity. The DS of fasting adult females was homogenized under acidic conditions and subjected to heat treatment. After that, samples were submitted to ion exchange batch and high-performance reverse-phase chromatography. The fractions with trypsin inhibitory activity were confirmed by mass spectrometry, identifying six molecules with inhibitory potential. The inhibitor NcTI (Nephilingis cruentata trypsin inhibitor) was kinetically characterized, showing a KD value of 30.25 nM ± 8.13. Analysis of the tertiary structure by molecular modeling using Alpha-Fold2 indicates that the inhibitor NcTI structurally belongs to the MIT1-like atracotoxin family. This is the first time that a serine peptidase inhibitory function is attributed to this structural family and the inhibitor reactive site residue is identified. Sequence analysis indicates that these molecules may be present in the DS of other spiders and could be associated to the inactivation of prey trypsin (serine peptidase) ingested by the spiders. [ABSTRACT FROM AUTHOR]

Serodiagnosis of human strongyloidiasis is a practical alternative to parasitological methods due to its high sensitivity. However, cross-reactivity with other helminth infections limits its utility, and this problem is due to the use of homologous or heterologous somatic extracts of the parasite as an antigen source. Excretory-secretory (E/S) products from Strongyloides infective larvae can be used to improve the serodiagnosis. The combined use of western blot and proteomics became an interesting strategy to identify immunological markers for the serodiagnosis of strongyloidiasis. The present study describes the proteomic analysis of the antigenic components from E/S products of S. venezuelensis infective larvae that were recognized by IgG antibodies from patients with strongyloidiasis. Our results showed that IgG antibodies from patients with strongyloidiasis recognized between 15 and 16 antigenic bands in the E/S products from S. venezuelensis that were incubated in PBS or in RPMI culture medium, respectively. Overall, antigenic bands of low and high molecular weight were more specific than those of intermediate molecular weight, which were cross-reactive. A 36-kDa antigenic band was 93% sensitive and 100% specific (a probably arginine kinase of 37 kDa), while other antigenic bands were highly sensitive but low specific. Proteomic analysis revealed differences between the protein profiles from E/S-RPMI and E/S-PBS since only one-third of all proteins identified were common in both types of E/S products. Bioinformatic analysis showed that more than 50% of the proteins from E/S products are secreted within extracellular vesicles and only a small percentage of them are actually released by the classical secretory pathway. Several components from the E/S products were identified as plasminogen-binding proteins, probably used as an immune evasion mechanism. The data provided here provide valuable information to increase understanding of E/S products from S. venezuelensis infective larvae. This may help us to find new targets for the immunodiagnosis of human strongyloidiasis. [ABSTRACT FROM AUTHOR]

Macrorhynchia philippina is a colonial benthic hydroid from the Class Hydrozoa (Phylum Cnidaria) distributed in the tropical and subtropical marine waters from Atlantic Ocean, Indo-Pacific, and Mozambique. Its colonies somewhat resemble plants, causing confusion in the bathers who accidentally touch the animal. Acute burning/local pain, edema, erythema, and pruritus were symptoms already described, but its venom composition is unknown, as well as the participation of toxins for the symptom's development. Thus, herein, we show the biochemical composition and toxic effects of M. philippina venom. Colonies were collected and processed for histological analysis; alternatively, they were immersed into methanol containing 0.1% acetic acid for venom attainment, which was analyzed by mass spectrometry and submitted to edema and nociception evaluation in mice, hemolysis and antimicrobial assays in vitro. Before the molecule's extraction, it was possible to see the inoculation structures (hydrocladiums and hydrotheca) containing venom, which was released after the immersion of the animal in the solvents. The venom was composed mainly by low molecular mass compounds, able to cause significant reduction of the paw withdrawal latency from the hot plate test, 30 minutes after the injection. Moreover, significant edema was observed 10 and 30 minutes after the injection, indicating the activity of at least two inflammatory mediators. The venom caused no hemolytic activity but reduced the growth of A. baumannii and K. pneumoniae strains. This study is the first biochemical description of M. philippina venom, with molecules that cause fast inflammatory and painful effects, characteristic of the envenomation. [ABSTRACT FROM AUTHOR]

An abstract of the article "Antiviral effects of Scaptotrigona postica propolis and their fractions" by Guilherme Rabelo Coelho and colleagues is presented.

Among the vast repertoire of animal toxins and venoms selected by nature and evolution, mankind opted to devote its scientific attention—during the last century—to a restricted group of animals, leaving a myriad of toxic creatures aside. There are several underlying and justifiable reasons for this, which include dealing with the public health problems caused by envenoming by such animals. However, these studies became saturated and gave rise to a whole group of animals that become neglected regarding their venoms and secretions. This repertoire of unexplored toxins and venoms bears biotechnological potential, including the development of new technologies, therapeutic agents and diagnostic tools and must, therefore, be assessed. In this review, we will approach such topics through an interconnected historical and scientific perspective that will bring up the major discoveries and innovations in toxinology, achieved by researchers from the Butantan Institute and others, and describe some of the major research outcomes from the study of these neglected animals. [ABSTRACT FROM AUTHOR]