Spider's Silk as a Potential Source of Antibiotics: An Integrative Review.

Spiders produce webs, which are still a largely unexplored source of antibacterial compounds, although the reports of its application in the medical field. Therefore, this study aims to present an integrative review of the antibacterial activity of spider webs. The research was conducted using Google Scholar, Scielo, Web of Science, PubMed, ScienceDirect, Medline EBSCO, LILACS, and Embase. The inclusion criteria were original articles written in English that studied the antibiotic properties of the web or isolated compounds tested. The studies were compared according to the spider species studied, the type of web, treatment of the sample, type of antimicrobial test, and the results obtained. Nine hundred and seventy-three publications were found, and after applying the inclusion and exclusion criteria, sixteen articles were selected. Bacterial inhibition was found in seven studies against various species of bacteria such as Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella Typhi, Bacillus megaterium, Listeria monocytogenes, Acinetobacter baumannii, Streptococcus pneumoniae, Pasteurella multocida, and Bacillus subtilis. Additionally, there was no apparent relationship between the proximity of the spider species evaluated in the studies and the presence or absence of activity. Methodological problems detected may affected the reproducibility and reliability of the results in some studies, such as the lack of description of the web or microorganism strain, as well as the absence of adequate controls and treatments to sterilize the sample. Spider webs can be a valuable source of antibiotics; however, more studies are needed to confirm the real activity of the web or components involved.

Bioengineering of spider silks for the production of biomedical materials.

Spider silks are well known for their extraordinary mechanical properties. This characteristic is a result of the interplay of composition, structure and self-assembly of spider silk proteins (spidroins). Advances in synthetic biology have enabled the design and production of spidroins with the aim of biomimicking the structure-property-function relationships of spider silks. Although in nature only fibers are formed from spidroins, in vitro, scientists can explore non-natural morphologies including nanofibrils, particles, capsules, hydrogels, films or foams. The versatility of spidroins, along with their biocompatible and biodegradable nature, also placed them as leading-edge biological macromolecules for improved drug delivery and various biomedical applications. Accordingly, in this review, we highlight the relationship between the molecular structure of spider silk and its mechanical properties and aims to provide a critical summary of recent progress in research employing recombinantly produced bioengineered spidroins for the production of innovative bio-derived structural materials.

Molecular Dynamics of Synthetic Flagelliform Silk Fiber Assembly.

In order to better understand the relationship between Flagelliform (Flag) spider silk molecular structural organization and the mechanisms of fiber assembly, it was designed and produced the Nephilengys cruentata Flag spidroin analogue rNcFlag2222. The recombinant proteins are composed by the elastic repetitive glycine-rich motifs (GPGGX/GGX) and the spacer region, rich in hydrophilic charged amino acids, present at the native silk spidroin. Using different approaches for nanomolecular protein analysis, the structural data of rNcFlag2222 recombinant proteins were compared in its fibrillar and in its fully solvated states. Based on the results was possible to identify the molecular structural dynamics of NcFlag2222 prior to and after fiber formation. Overal rNcFlag2222 shows a mixture of semiflexible and rigid conformations, characterized mostly by the presence of PPII, ß-turn and ß-sheet. These results agree with previous studies and bring insights about the molecular mechanisms that might driven Flag silk fibers assembly and elastomeric behavior.

Thermal, structural and mechanical characterization of Nephila clavipes spider silk in southwest Colombia.

Some physical properties of spider silks, including mechanical strength and toughness, have been studied in many laboratories worldwide. Given that this silk is organic in nature, composed of protein, and has similar properties to metal wires or polymers, it has the potential for application in medicine, nanoelectronics, and other related areas. In this study, we worked on spider silk from the Nephila clavipes species collected from the wild and kept it in the nursery of the Autonomous University of the West, Cali, Colombia, to determine its physical, thermal, and mechanical properties, seeking possible applications in the medical and industrial sectors and comparing the material properties of the silk from the species from southwestern Colombia with those of the previously studied species from other regions. The mechanical characterization of the material was performed using a universal testing machine; thermal behavior was captured by a thermogravimetric analysis, differential scanning calorimetry, and mass spectrometry; and structural characterization was performed using diffraction X-rays. The results of the thermal characterization demonstrate that the spider silk loses 10 % of water content at 150 °C with significant changes at 400 °C, while the mechanical characterization indicates that the spider silk is much tougher than Kevlar 49 and Nylon 6 since it is capable of absorbing more energy before rupture.

Application of the Spider Silk Standardization Initiative (S3I) methodology to the characterization of major ampullate gland silk fibers spun by spiders from Pantanos de Villa wetlands (Lima, Peru).

Spider silk is a natural material with unique properties and a great potential for engineering and biomedical applications. In spite of its simple composition and highly conserved and stereotypical production, spider silks show a wide range of variability in their mechanical properties which, for long, have defied their classification and standardization. Here we propose to launch the Spider Silk Standardization Initiative (S3I), a methodology based on the definition of the α* parameter, in an attempt to define a systematic procedure to classify the tensile properties exhibited by major ampullate gland silk (MAS) spun by Entelegynae spiders. The α* parameter is calculated from the comparison of the true stress-true strain curve of any MAS fiber after being subjected to maximum supercontraction, with the true stress-true strain curve of the species Argiope aurantia, which is set as a reference curve. This work presents the details of the S3I methodology and, as an example, shows its application to an assemblage of Entelegynae spiders from different families collected at the Pantanos de Villa wetlands (Lima, Peru). The systematic and objective classification of the tensile properties of MAS fibers allowed by the S3I will offer insights into key aspects of the biological evolution of the material, and address questions such as how history and adaptation contributed to shape those properties. In addition, it will surely have far reaching consequences in fields such as Materials Science, and Molecular and Evolutionary Biology, by organizing the range of tensile properties exhibited by spider silk fibers.

Revealing the Venomous Secrets of the Spider's Web.

Orb-weaving spiders use a highly strong, sticky and elastic web to catch their prey. These web properties alone would be enough for the entrapment of prey; however, these spiders may be hiding venomous secrets in the web, which current research is revealing. Here, we provide strong proteotranscriptomic evidence for the presence of toxin/neurotoxin-like proteins, defensins, and proteolytic enzymes on the web silk from Nephila clavipes spider. The results from quantitative-based transcriptomic and proteomic approaches showed that silk-producing glands produce an extensive repertoire of toxin/neurotoxin-like proteins, similar to those already reported in spider venoms. Meanwhile, the insect toxicity results demonstrated that these toxic components can be lethal and/or paralytic chemical weapons used for prey capture on the web, and the presence of fatty acids in the web may be a responsible mechanism opening the way to the web toxins for accessing the interior of prey's body, as shown here. Comparative phylogenomic-level evolutionary analyses revealed orthologous genes among two spider groups, Araneomorphae and Mygalomorphae, and the findings showed protein sequences similar to toxins found in the taxa Scorpiones and Hymenoptera in addition to Araneae. Overall, these data represent a valuable resource to further investigate other spider web toxin systems and also suggest that N. clavipes web is not a passive mechanical trap for prey capture, but it exerts an active role in prey paralysis/killing using a series of neurotoxins.

Esculent coating of spider silk enhanced the preservation and shelf life of apricot / A cobertura escamada de seda de aranha aumentou a preservação e a vida útil do damasco

Abstract According to the Food and Agriculture Organization (FAO), roughly one-third of the total food produced is lost globally. The major cause of this wastage is the perishability of fruits and vegetables. Therefore, researchers have endeavored to develop an effective preservation technique. Our study explored the potential application of spider silk as an odourless and edible preservative coating for fruits. The spider silk was collected from spiders reared in the laboratory, following by degumming and dissolution to formulate the silk solution. For this study, apricots were selected as the model fruit. The apricots were dip coated with the formulated silk solution and allowed to dry. In order to enhance the beta sheet content of the silk coating, the fruits were exposed to water annealing for varying intervals of time under vacuum condition. The effect of silk coating and water annealing time period on preservation of fruits was then evaluated morphologically and gravimetrically. The results showed that the fruits, which were used as control, exhibited a greater degree of water loss and suffered from fungal attack. In contrast, the silk coated fruits showed less water loss and were protected from fungal attack. Therefore, the study provides compelling evidence regarding the application of spider silk as a preservative coating.

Resumo Segundo a Organização para Alimentação e Agricultura (FAO), cerca de um terço do total de alimentos produzidos é perdido globalmente. A principal causa deste desperdício é a perecibilidade das frutas e legumes. Portanto, os pesquisadores têm se esforçado para desenvolver uma técnica de preservação eficaz. Nosso estudo explorou a potencial aplicação de seda de aranha como um revestimento conservante inodoro e comestível para frutas. A seda da aranha foi coletada de aranhas criadas em laboratório, seguindo-se a degomagem e dissolução para formular a solução de seda. Para este estudo, os damascos foram selecionados como fruto modelo. Os damascos foram revestidos por imersão com a solução de seda formulada e deixados secar. A fim de aumentar o teor de folhas beta do revestimento de seda, os frutos foram expostos a recozimento de água durante vários intervalos de tempo sob condições de vácuo. O efeito do tempo de recobrimento de seda e recozimento de água na preservação de frutos foi então avaliado morfologicamente e gravimetricamente. Os resultados mostraram que os frutos, utilizados como controle, apresentaram maior grau de perda de água e sofreram ataque fúngico. Em contraste, os frutos revestidos de seda mostraram menos perda de água e foram protegidos contra ataques fúngicos. Portanto, o estudo fornece evidências convincentes sobre a aplicação de seda de aranha como um revestimento conservante.

Esculent coating of spider silk enhanced the preservation and shelf life of apricot / A cobertura escamada de seda de aranha aumentou a preservação e a vida útil do damasco

According to the Food and Agriculture Organization (FAO), roughly one-third of the total food produced is lost globally. The major cause of this wastage is the perishability of fruits and vegetables. Therefore, researchers have endeavored to develop an effective preservation technique. Our study explored the potential application of spider silk as an odourless and edible preservative coating for fruits. The spider silk was collected from spiders reared in the laboratory, following by degumming and dissolution to formulate the silk solution. For this study, apricots were selected as the model fruit. The apricots were dip coated with the formulated silk solution and allowed to dry. In order to enhance the beta sheet content of the silk coating, the fruits were exposed to water annealing for varying intervals of time under vacuum condition. The effect of silk coating and water annealing time period on preservation of fruits was then evaluated morphologically and gravimetrically. The results showed that the fruits, which were used as control, exhibited a greater degree of water loss and suffered from fungal attack. In contrast, the silk coated fruits showed less water loss and were protected from fungal attack. Therefore, the study provides compelling evidence regarding the application of spider silk as a preservative coating.(AU)

Segundo a Organização para Alimentação e Agricultura (FAO), cerca de um terço do total de alimentos produzidos é perdido globalmente. A principal causa deste desperdício é a perecibilidade das frutas e legumes. Portanto, os pesquisadores têm se esforçado para desenvolver uma técnica de preservação eficaz. Nosso estudo explorou a potencial aplicação de seda de aranha como um revestimento conservante inodoro e comestível para frutas. A seda da aranha foi coletada de aranhas criadas em laboratório, seguindo-se a degomagem e dissolução para formular a solução de seda. Para este estudo, os damascos foram selecionados como fruto modelo. Os damascos foram revestidos por imersão com a solução de seda formulada e deixados secar. A fim de aumentar o teor de folhas beta do revestimento de seda, os frutos foram expostos a recozimento de água durante vários intervalos de tempo sob condições de vácuo. O efeito do tempo de recobrimento de seda e recozimento de água na preservação de frutos foi então avaliado morfologicamente e gravimetricamente. Os resultados mostraram que os frutos, utilizados como controle, apresentaram maior grau de perda de água e sofreram ataque fúngico. Em contraste, os frutos revestidos de seda mostraram menos perda de água e foram protegidos contra ataques fúngicos. Portanto, o estudo fornece evidências convincentes sobre a aplicação de seda de aranha como um revestimento conservante.(AU)

Esculent coating of spider silk enhanced the preservation and shelf life of apricot

Abstract According to the Food and Agriculture Organization (FAO), roughly one-third of the total food produced is lost globally. The major cause of this wastage is the perishability of fruits and vegetables. Therefore, researchers have endeavored to develop an effective preservation technique. Our study explored the potential application of spider silk as an odourless and edible preservative coating for fruits. The spider silk was collected from spiders reared in the laboratory, following by degumming and dissolution to formulate the silk solution. For this study, apricots were selected as the model fruit. The apricots were dip coated with the formulated silk solution and allowed to dry. In order to enhance the beta sheet content of the silk coating, the fruits were exposed to water annealing for varying intervals of time under vacuum condition. The effect of silk coating and water annealing time period on preservation of fruits was then evaluated morphologically and gravimetrically. The results showed that the fruits, which were used as control, exhibited a greater degree of water loss and suffered from fungal attack. In contrast, the silk coated fruits showed less water loss and were protected from fungal attack. Therefore, the study provides compelling evidence regarding the application of spider silk as a preservative coating.

Resumo Segundo a Organização para Alimentação e Agricultura (FAO), cerca de um terço do total de alimentos produzidos é perdido globalmente. A principal causa deste desperdício é a perecibilidade das frutas e legumes. Portanto, os pesquisadores têm se esforçado para desenvolver uma técnica de preservação eficaz. Nosso estudo explorou a potencial aplicação de seda de aranha como um revestimento conservante inodoro e comestível para frutas. A seda da aranha foi coletada de aranhas criadas em laboratório, seguindo-se a degomagem e dissolução para formular a solução de seda. Para este estudo, os damascos foram selecionados como fruto modelo. Os damascos foram revestidos por imersão com a solução de seda formulada e deixados secar. A fim de aumentar o teor de folhas beta do revestimento de seda, os frutos foram expostos a recozimento de água durante vários intervalos de tempo sob condições de vácuo. O efeito do tempo de recobrimento de seda e recozimento de água na preservação de frutos foi então avaliado morfologicamente e gravimetricamente. Os resultados mostraram que os frutos, utilizados como controle, apresentaram maior grau de perda de água e sofreram ataque fúngico. Em contraste, os frutos revestidos de seda mostraram menos perda de água e foram protegidos contra ataques fúngicos. Portanto, o estudo fornece evidências convincentes sobre a aplicação de seda de aranha como um revestimento conservante.

Ants Do Not Traverse the Silk of Adult Female Nephila clavipes (Linnaeus) Webs.

Many organisms use chemicals to deter enemies. Some spiders can modify the composition of their silk to deter predators from climbing onto their webs. The Malaysian golden orb-weaver Nephila antipodiana (Walckenaer) produces silk containing an alkaloid (2-pyrrolidinone) that functions as a defense against ant invasion-ants avoid silk containing this chemical. In the present study, we test the generality of ants' silk avoidance behavior in the field. We introduced three ant species to the orb webs of Nephila clavipes (Linnaeus) in the tropical rainforest of La Selva, Costa Rica. We found that predatory army ants (Eciton burchellii Westwood) as well as non-predatory leaf-cutting ants (Atta cephalotes Linnaeus and Acromyrmex volcanus Wheeler) avoided adult N. clavipes silk, suggesting that an additional species within genus Nephila may possess ant-deterring silk. Our field assay also suggests that silk avoidance behavior is found in multiple ant species.

Esculent coating of spider silk enhanced the preservation and shelf life of apricot

Abstract According to the Food and Agriculture Organization (FAO), roughly one-third of the total food produced is lost globally. The major cause of this wastage is the perishability of fruits and vegetables. Therefore, researchers have endeavored to develop an effective preservation technique. Our study explored the potential application of spider silk as an odourless and edible preservative coating for fruits. The spider silk was collected from spiders reared in the laboratory, following by degumming and dissolution to formulate the silk solution. For this study, apricots were selected as the model fruit. The apricots were dip coated with the formulated silk solution and allowed to dry. In order to enhance the beta sheet content of the silk coating, the fruits were exposed to water annealing for varying intervals of time under vacuum condition. The effect of silk coating and water annealing time period on preservation of fruits was then evaluated morphologically and gravimetrically. The results showed that the fruits, which were used as control, exhibited a greater degree of water loss and suffered from fungal attack. In contrast, the silk coated fruits showed less water loss and were protected from fungal attack. Therefore, the study provides compelling evidence regarding the application of spider silk as a preservative coating.

Resumo Segundo a Organização para Alimentação e Agricultura (FAO), cerca de um terço do total de alimentos produzidos é perdido globalmente. A principal causa deste desperdício é a perecibilidade das frutas e legumes. Portanto, os pesquisadores têm se esforçado para desenvolver uma técnica de preservação eficaz. Nosso estudo explorou a potencial aplicação de seda de aranha como um revestimento conservante inodoro e comestível para frutas. A seda da aranha foi coletada de aranhas criadas em laboratório, seguindo-se a degomagem e dissolução para formular a solução de seda. Para este estudo, os damascos foram selecionados como fruto modelo. Os damascos foram revestidos por imersão com a solução de seda formulada e deixados secar. A fim de aumentar o teor de folhas beta do revestimento de seda, os frutos foram expostos a recozimento de água durante vários intervalos de tempo sob condições de vácuo. O efeito do tempo de recobrimento de seda e recozimento de água na preservação de frutos foi então avaliado morfologicamente e gravimetricamente. Os resultados mostraram que os frutos, utilizados como controle, apresentaram maior grau de perda de água e sofreram ataque fúngico. Em contraste, os frutos revestidos de seda mostraram menos perda de água e foram protegidos contra ataques fúngicos. Portanto, o estudo fornece evidências convincentes sobre a aplicação de seda de aranha como um revestimento conservante.

An experimental confirmation of thermal transitions in native and regenerated spider silks.

Biological structures such as spider silks are formed by proteins. The physical properties of such proteins are determined by environmental conditions such as temperature and humidity. In this paper, we confirm the thermal transitions that take place in spider silks using differential scanning calorimetry and study how the interaction of spider silk proteins with water affects the onset temperatures for these thermal processes. Native fibres and regenerated films of dragline silk and egg sac silk from Argiope argentata spiders were used to study thermal transitions of protein based structures. For the first time, differential scanning calorimetry (DSC) tests were carried out with spider silk samples of relatively large mass (10mg). Previous attempts of DSC tests applied to spider silk samples failed to detect thermal transitions in a conclusive way. The tests reported here, however, show thermal transitions on both natural and regenerated samples that are in agreement with results from dynamic mechanical analysis (DMA) tests reported in the literature. The water content on spider silks seems to lower the temperatures at which such thermal transitions take place. The results also confirm that the amorphous regions of native and regenerated spider silk and silk worm silk give rise to similar thermal transitions.