Peculiar Phosphonate Modifications of Velvet Worm Slime Revealed by Advanced Nuclear Magnetic Resonance and Mass Spectrometry.

Nature is rich with examples of highly specialized biological materials produced by organisms for functions, including defense, hunting, and protection. Along these lines, velvet worms (Onychophora) expel a protein-based slime used for hunting and defense that upon shearing and dehydration forms fibers as stiff as thermoplastics. These fibers can dissolve back into their precursor proteins in water, after which they can be drawn into new fibers, providing biological inspiration to design recyclable materials. Elevated phosphorus content in velvet worm slime was previously observed and putatively ascribed to protein phosphorylation. Here, we show instead that phosphorus is primarily present as phosphonate moieties in the slime of distantly related velvet worm species. Using high-resolution nuclear magnetic resonance (NMR), natural abundance dynamic nuclear polarization (DNP), and mass spectrometry (MS), we demonstrate that 2-aminoethyl phosphonate (2-AEP) is associated with glycans linked to large slime proteins, while transcriptomic analyses confirm the expression of 2-AEP synthesizing enzymes in slime glands. The evolutionary conservation of this rare protein modification suggests an essential functional role of phosphonates in velvet worm slime and should stimulate further study of the function of this unusual chemical modification in nature.

The Internal Structure of the Velvet Worm Projectile Slime: A Small-Angle Scattering Study.

For prey capture and defense, velvet worms eject an adhesive slime which has been established as a model system for recyclable complex liquids. Triggered by mechanical agitation, the liquid bio-adhesive rapidly transitions into solid fibers. In order to understand this mechanoresponsive behavior, here, the nanostructural organization of slime components are studied using small-angle scattering with neutrons and X-rays. The scattering intensities are successfully described with a three-component model accounting for proteins of two dominant molecular weight fractions and nanoscale globules. In contrast to the previous assumption that high molecular weight proteins-the presumed building blocks of the fiber core-are contained in the nanoglobules, it is found that the majority of slime proteins exist freely in solution. Only less than 10% of the slime proteins are contained in the nanoglobules, necessitating a reassessment of their function in fiber formation. Comparing scattering data of slime re-hydrated with light and heavy water reveals that the majority of lipids in slime are contained in the nanoglobules with homogeneous distribution. Vibrating mechanical impact under exclusion of air neither leads to formation of fibers nor alters the bulk structure of slime significantly, suggesting that interfacial phenomena and directional shearing are required for fiber formation.

Comparative Animal Mucomics: Inspiration for Functional Materials from Ubiquitous and Understudied Biopolymers.

The functions of secreted animal mucuses are remarkably diverse and include lubricants, wet adhesives, protective barriers, and mineralizing agents. Although present in all animals, many open questions related to the hierarchical architectures, material properties, and genetics of mucus remain. Here, we summarize what is known about secreted mucus structure, describe the work of research groups throughout the world who are investigating various animal mucuses, and relate how these studies are revealing new mucus properties and the relationships between mucus hierarchical structure and hydrogel function. Finally, we call for a more systematic approach to studying animal mucuses so that data sets can be compared, omics-style, to address unanswered questions in the emerging field of mucomics. One major result that we anticipate from these efforts is design rules for creating new materials that are inspired by the structures and functions of animal mucuses.

Two coastal Pacific evergreens, Arbutus menziesii, Pursh. and Quercus agrifolia, Née show little water stress during California's exceptional drought.

California's coastal climate is characterized by rainy winters followed by a dry summer season that is supplemented by frequent fog. While rising temperatures and drought caused massive tree mortality in central California during the 2011-2015 extreme drought, dying trees were less common in the central coast region. We hypothesized that cooler, maritime-ameliorated temperatures reduced the effects of drought stress on coastal vegetation. To test this, weekly measurements of water potential and stomatal conductance were made on two coast evergreen tree species, Arbutus menziesii and Quercus agrifolia, throughout the summer 2014 dry season. Water potential remained generally constant during this period but stomatal conductance declined in both species as the dry season progressed. Species' resistance to embolism was determined using the centrifuge method, and showed Q. agrifolia to be more vulnerable to embolism than A. menziesii. The stem vulnerability curves were consistent with species' seasonal water relations as well as their anatomy; the ring-porous Q. agrifolia had substantially larger conduits than the diffuse-porous A. menziesii. Leaf turgor loss points differed significantly as did other pressure-volume parameters but these data were consistent with the trees' seasonal water relations. Overall, the two species appear to employ differing water use strategies; A. menziesii is more profligate in its water use, while Q. agrifolia is more conservative, with a narrower safety margin against drought-induced loss of xylem transport capacity. Despite the extended drought, these species exhibited neither branch die-back nor any obvious symptoms of pronounced water-stress during the study period, implying that the maritime climate of California's central coast may buffer the local vegetation against the severe effects of prolonged drought.

Fibers on the Fly: Multiscale Mechanisms of Fiber Formation in the Capture Slime of Velvet Worms.

Many organisms have evolved a capacity to form biopolymeric fibers outside their bodies for functions such as defense, prey capture, attachment, and protection. In particular, the adhesive capture slime of onychophorans (velvet worms) is remarkable for its ability to rapidly form stiff fibers through mechanical drawing. Notably, fibers that are formed ex vivo from extracted slime can be dissolved in water and new fibers can be drawn from the solution, indicating that fiber formation is encoded in the biomolecules that comprise the slime. This review highlights recent findings on the biochemical and physicochemical principles guiding this circular process in the Australian onychophoran Euperipatoides rowelli. A multiscale cross-disciplinary approach utilizing techniques from biology, biochemistry, physical chemistry, and materials science has revealed that the slime is a concentrated emulsion of nanodroplets comprised primarily of proteins, stabilized via electrostatic interactions, possibly in a coacervate phase. Upon mechanical agitation, droplets coalesce, leading to spontaneous self-assembly and fibrillation of proteins-a completely reversible process. Recent investigations highlight the importance of subtle transitions in protein structure and charge balance. These findings have clear relevance for better understanding this adaptive prey capture behavior and providing inspiration toward sustainable polymer processing.

Shear-Induced ß-Crystallite Unfolding in Condensed Phase Nanodroplets Promotes Fiber Formation in a Biological Adhesive.

Natural materials provide an increasingly important role model for the development and processing of next-generation polymers. The velvet worm Euperipatoides rowelli hunts using a projectile, mechanoresponsive adhesive slime that rapidly and reversibly transitions into stiff glassy polymer fibers following shearing and drying. However, the molecular mechanism underlying this mechanoresponsive behavior is still unclear. Previous work showed the slime to be an emulsion of nanoscale charge-stabilized condensed droplets comprised primarily of large phosphorylated proteins, which under mechanical shear coalesce and self-organize into nano- and microfibrils that can be drawn into macroscopic fibers. Here, we utilize wide-angle X-ray diffraction and vibrational spectroscopy coupled with in situ shear deformation to explore the contribution of protein conformation and mechanical forces to the fiber formation process. Although previously believed to be unstructured, our findings indicate that the main phosphorylated protein component possesses a significant ß-crystalline structure in the storage phase and that shear-induced partial unfolding of the protein is a key first step in the rapid self-organization of nanodroplets into fibers. The insights gained here have relevance for sustainable production of advanced polymeric materials.

Reversible Supramolecular Assembly of Velvet Worm Adhesive Fibers via Electrostatic Interactions of Charged Phosphoproteins.

Velvet worms secrete a fluid hunting slime comprised of a dispersion of nanoglobules that form microfibers under small mechanical shear forces, facilitating the rapid formation of stiff biopolymeric fibers. Here, we demonstrate that the nanoglobules are held together and stabilized as a dispersion by electrostatic interactions reminiscent of coacervate-based natural adhesives. Variation of ionic strength and pH affects the stability of nanoglobules and their ability to form fibers. Fibers mainly consist of large (∼300 kDa), highly charged proteins, and current biochemical analysis reveals a high degree of protein phosphorylation and presence of divalent cations. Taken together, we surmise that polyampholytic protein sequences, phosphorylated sites, and ions give rise to transient ionic cross-linking, enabling reversible curing of ejected slime into high-stiffness fibers following dehydration. These results provide a deeper understanding of velvet worm adhesive fibers, which may stimulate new routes toward mechanoresponsive and sustainable materials.

Mechanoresponsive lipid-protein nanoglobules facilitate reversible fibre formation in velvet worm slime.

Velvet worms eject a fluid capture slime that can be mechanically drawn into stiff biopolymeric fibres. Remarkably, these fibres can be dissolved by extended exposure to water, and new regenerated fibres can be drawn from the dissolved fibre solution-indicating a fully recyclable process. Here, we perform a multiscale structural and compositional investigation of this reversible fabrication process with the velvet worm Euperipatoides rowelli, revealing that biopolymeric fibre assembly is facilitated via mono-disperse lipid-protein nanoglobules. Shear forces cause nanoglobules to self-assemble into nano- and microfibrils, which can be drawn into macroscopic fibres with a protein-enriched core and lipid-rich coating. Fibre dissolution in water leads to re-formation of nanoglobules, suggesting that this dynamic supramolecular assembly of mechanoresponsive protein-building blocks is mediated by reversible non-covalent interactions. These findings offer important mechanistic insights into the role of mechanochemical processes in bio-fibre formation, providing potential avenues for sustainable material fabrication processes.Velvet worms expel a fluid slime that, under shear force, forms stiff fibres that can be dissolved and then regenerated. Here, the authors reveal that the recyclability of these biopolymers relies on mechanoresponsive lipid-protein nanoglobules in the slime that reversibly self-assemble into fibrils.

Capture of Prey, Feeding, and Functional Anatomy of the Jaws in Velvet Worms (Onychophora).

Onychophorans are carnivorous, terrestrial invertebrates that occur in tropical and temperate forests of the Southern Hemisphere and around the Equator. Together with tardigrades, onychophorans are regarded as one of the closest relatives of arthropods. One of the most peculiar features of onychophorans is their hunting and feeding behavior. These animals secrete a sticky slime, which is ejected via a pair of slime-papillae, to entangle the prey. After the prey has been immobilized, its cuticle is punctured using a pair of jaws located within the mouth. These jaws constitute internalized appendages of the second body segment and are innervated by the deutocerebrum; thus, they are homologous to the chelicerae of chelicerates, and to the (first) antennae of myriapods, crustaceans, and insects. The jaws are also serial homologs of the paired claws associated with each walking limb of the trunk. The structure of the jaws is similar in representatives of the two major onychophoran subgroups, the Peripatidae and Peripatopsidae. Each jaw is characterized by an outer and an inner blade; while the outer blade consists only of a large principal tooth and up to three accessory teeth, the inner blade bears numerous additional denticles. These denticles are separated from the remaining part of the inner jaw by a diastema and a soft membrane only in peripatids. The onychophoran jaws are associated with large apodemes and specialized muscles that enable their movement. In contrast to the mandibles of arthropods, the onychophoran jaws are moved along, rather than perpendicular to, the main axis of the body. Our elemental analysis reveals an increased incorporation of calcium at the tip of each blade, which might provide rigidity, whereas there is no evidence for incorporation of metal or prominent mineralization. Stability of the jaw might be further facilitated by the cone-in-cone organization of its cuticle, as each blade consists of several stacked, cuticular elements. In this work, we summarize current knowledge on the jaws of onychophorans, which are a characteristic feature of these animals.

Comparative anatomy of slime glands in onychophora (velvet worms).

Onychophorans use a unique hunting and defense strategy, which involves the ejection of an adhesive slime secretion produced by a pair of specialized glands. So far, a comparative study on the anatomy of these glands has not been carried out among different species. In this article, we compare anatomical features of slime glands in representatives of two major onychophoran subgroups, the Peripatopsidae and the Peripatidae, from different parts of the world. Our data show that the musculature of the reservoir is conserved whereas the composition of the secretory duct displays taxon-specific variation. Major differences concern the arrangement of glandular endpieces, which are distributed along the duct in Peripatopsidae but condensed in numerous repeated rosettes in Peripatidae. In addition, there are differences in the attachment pattern of slime glands to the inner surface of the body wall and to the outer surface of the gut between the two major onychophoran subgroups. A tube-like structure with a putative valve-like function is found at the transition of the secretory duct and the reservoir in the five Peripatopsidae species studied whereas it is absent in the two representatives of Peripatidae. Our findings suggest that the arrangement of musculature in the reservoir of the slime gland has remained unchanged since the divergence of Peripatidae and Peripatopsidae, while the composition of the secretory duct has been altered in one of these groups. However, the direction of evolutionary changes in duct composition cannot be determined unambiguously due to current uncertainty regarding the phylogenetic relationships of Onychophora.

Poison centers as information resources for volunteer EMS in a suspected chemical exposure.

In the early part of chemical terrorism or hazardous materials events, protective actions and patient care require empirical decisions because reliable and accurate information may not be readily available. It has become increasingly important to identify reliable information resources that are the most likely to be accessed for information during these events. We sought to identify information resources that volunteer Emergency Medical Services (EMS) providers would use during a suspected chemical exposure. Survey questionnaires were completed by 116 of 151 (76.8%) suburban and rural EMS providers. In the past 12 months, most participants used medical journals and textbooks (59.5%), internet sites (57.8%), and poison centers (55.2%) as information resources. For two hypothetical scenarios involving chemical exposures, poison centers were most frequently chosen as likely contacts for information regarding the identity of the agent (case 1: 52.6%, case 2: 48.3%), treatment (74.1%, 64.7%, respectively), and antidote (59.5%, 49.1%, respectively). Fire department hazardous materials team tied with poison centers as the highest for chemical agent in the second scenario (48.3%) and was ranked highest both for decontamination (75.0%, 64.7%, respectively) and personal protection (56.9%, 45.7%, respectively). Poison centers were selected as the best resource for timely information (70.7%), availability (69.0%), and ease of contact (72.4%), and second highest for knowledge of chemical agents (44.0%), after CHEMTREC (56.9%). Finally, poison centers and CHEMTREC received the highest overall ratings (28.4% and 26.7%, respectively). Poison centers are viewed as an important information resource by EMS providers and may be the most commonly sought resource for various information needs during a suspected chemical exposure.

Analysis of moonshine for contaminants.

OBJECTIVES: In the past, some moonshine products contained potentially toxic contaminants. Although moonshine production continues in the United States, no studies have analyzed the content of moonshine since the early 1960s. We hypothesize that moonshine continues to contain potentially toxic concentrations of contaminants. METHODS: Forty-eight samples of illicitly distilled moonshine were obtained from law enforcement agencies. An independent laboratory, blinded to both the moonshine source and a control sample of ethanol, conducted the analysis. Lead content was determined using atomic absorption spectrophotometry with a graphite tube atomizer. Alcohol content, including ethanol, acetone, isopropanol, methanol, and ethylene glycol, was determined using gas liquid chromatography with flame ionization detection. RESULTS: Ethanol content ranged from 10.5% to 66.0% with a mean value of 41.2%. Lead was found in measurable quantities in 43 of 48 samples with values ranging from 5 to 599 parts per billion (ppb) with a mean value of 80.7 ppb. A total of 29 of 48 (60%) of samples contained lead concentrations above or equal to the EPA water guideline of 15 ppb. Methanol was found in only one sample at a concentration of 0.11%. No samples contained detectable concentrations of acetone, isopropanol, or ethylene glycol. CONCLUSIONS: Many moonshine samples contain detectable concentrations of lead. Extrapolations based on the described moonshine lead content suggest that chronic consumers of moonshine may develop elevated lead concentrations. Physicians should consider lead toxicity in the differential diagnosis when evaluating patients consuming moonshine.

Insecticides.

Organophosphate (OP) insecticide toxicity is the leading cause of major morbidity and death in the insecticides class. The clinical syndrome of OP toxicity varies widely, ranging from the classic cholinergic syndrome to flaccid paralysis and intractable seizures. The mainstays of therapy for OP-poisoned patients are atropine, pralidoxime, and benzodiazepines. Tachycardia is not a contraindication to treatment with atropine in OP toxicity. Atropine should be administered to alleviate respiratory distress, symptomatic bradycardia, and as an adjunct to benzodiazepines to alleviate seizure activity. Atropine should not be administered systemically to alleviate miosis. In acute OP toxicity, a continuous pralidoxime infusion should be considered. Intermediate syndrome and OP-induced delayed neuropathy may occur in select patients with OP poisoning.

Massive caffeine overdose requiring vasopressin infusion and hemodialysis.

INTRODUCTION: Massive caffeine overdose is associated with life-threatening hemodynamic complications that present challenges for clinicians. We describe the highest-reported serum concentration of caffeine in a patient who survived and discuss the first-reported use of vasopressin and hemodialysis in a caffeine-poisoned patient. CASE REPORT: A 41-yr-old woman presented 3 h after ingesting approximately 50 g of caffeine. She subsequently underwent cardiopulmonary resuscitation and received multiple medications in an attempt to raise her blood pressure and control her heart rate without success. Vasopressin infusion increased her blood pressure to the point where hemodialysis could be performed. Despite ensuing multisystem organ failure, she survived and has made a complete recovery. CONCLUSION: Hemodialysis and vasopressin infusions may be of benefit in the management of caffeine-intoxicated patients who fail to respond to standard therapies.

Immediate hypersensitivity reaction associated with the rapid infusion of Crotalidae polyvalent immune Fab (ovine).

A 16-year-old boy presented to the emergency department with rapidly progressing extremity pain, edema, and ecchymosis after envenomation by a copperhead. Crotalidae polyvalent immune Fab (ovine) (CroFab; FabAV) was infused. Six vials were placed in 250 mL of normal saline solution, and the infusion was gradually increased. Fifty minutes after beginning, the infusion was increased to 640 mL/h. Within minutes of the rate increase, the patient experienced full-body urticaria, facial edema, voice change, and tachycardia. The infusion was stopped. Hydroxyzine pamoate, famotidine, methylprednisolone, and a 1-L bolus of normal saline solution were administered intravenously. The symptoms abated, and the remaining FabAV was infused at a slower rate without return of this reaction. This immediate hypersensitivity reaction was most likely a rate-related anaphylactoid reaction that has not been previously reported with FabAV.[Holstege CP, Wu J, Baer AB. Immediate hypersensitivity reaction associated with the rapid infusion of Crotalidae polyvalent immune Fab (ovine). Ann Emerg Med. June 2002;39:677-679.]