A ‘NanoSuit’ surface shield successfully protects organisms in high vacuum: observations on living organisms in an FE-SEM

Although extremely useful for a wide range of investigations, the field emission scanning electron microscope (FE-SEM) has not allowed researchers to observe living organisms. However, we have recently reported that a simple surface modification consisting of a thin extra layer, termed ‘NanoSuit’, can keep organisms alive in the high vacuum (10⁻⁵ to 10⁻⁷ Pa) of the SEM. This paper further explores the protective properties of the NanoSuit surface-shield. We found that a NanoSuit formed with the optimum concentration of Tween 20 faithfully preserves the integrity of an organism''s surface without interfering with SEM imaging. We also found that electrostatic charging was absent as long as the organisms were alive, even if they had not been coated with electrically conducting materials. This result suggests that living organisms possess their own electrical conductors and/or rely on certain properties of the surface to inhibit charging. The NanoSuit seems to prolong the charge-free condition and increase survival time under vacuum. These findings should encourage the development of more sophisticated observation methods for studying living organisms in an FE-SEM.     

Crystal structure of a fully glycosylated HIV‐1 gp120 core reveals a stabilizing role for the glycan at Asn262

The crystal structure of a fully glycosylated HIV‐1 gp120 core in complex with CD4 receptor and Fab 17b at 4.5‐Å resolution reveals 9 of the 15 N‐linked glycans of core gp120 to be partially ordered. The glycan at position Asn262 had the most extensive and well‐ordered electron density, and a GlcNAc₂Man₇ was modeled. The GlcNAc stem of this glycan is largely buried in a cleft in gp120, suggesting a role in gp120 folding and stability. Its arms interact with the stems of neighboring glycans from the oligomannose patch, which is a major target for broadly neutralizing antibodies. Proteins 2015; 83:590–596. © 2014 Wiley Periodicals, Inc.     

Microstructure of pretarsal pulvilli in shield bug Acanthosoma spinicolle (Heteroptera: Acanthosomatidae)

Shield bugs effectively attach themselves on both rough and smooth surfaces, but their advanced biological attachment devices have not been studied closely. Our fine structural examination of the attachment devices in the shield bug A. spinicolle reveals a unique system to achieve extraordinary adhesion that allows vertical climbing. Each appendage has a pair of tarsal claws that attach to rough substrates and a pair of pretarsal pulvilli that attach to smooth surfaces. Similar to other heteropteran insects, the pulvilli of this bug are categorized as a wet adhesion system, which makes use of an adhesive fluid from the pad secretion. However, this deformable pad creates a regular pattern of contact with the mating surface with a compact array of microfolds and setae with filamentous distal protrusions. To date, this distinctive microstructure in pulvilli pads has never been reported. These microstructural characteristics should be further studied to understand biological adhesion as well as create biomimetic applications.     

Revision of Sternaspis Otto, 1821 (Polychaeta,?Sternaspidae)

To the memory of William Ronald Sendall Sternaspid polychaetes are common and often abundant in soft bottoms in the world oceans. Some authors suggest that only one species should be recognized, whereas others regard a few species as widely distributed in many seas and variable depths from the low intertidal to about 4400 m. There are some problems with species delineation and the distinctive ventro-caudal shield has been disregarded or barely used for identifying species. In order to clarify these issues, the ventral shield is evaluated in specimens from the same locality and its diagnostic potential is confirmed. On this basis, a revision of Sternaspis Otto, 1821 (Polychaeta: Sternaspidae) is presented based upon type materials, or material collected from type localities. The sternaspid body, introvert hooks and shield show three distinct patterns, two genera have seven abdominal segments and tapered introvert hooks, and one genus has eight abdominal segments and spatulate introvert hooks. The ventro-caudal shield has three different patterns: stiff with ribs, and sometimes concentric lines, stiff with feebly-defined ribs but no concentric lines, and soft with firmly adhered sediment particles. Sternaspis is restricted to include species with seven abdominal segments, falcate introvert hooks, and stiff shields, often exhibiting radial ribs, concentric lines or both. Sternaspis includes, besides the type species, Sternaspis thalassemoides Otto, 1821 from the Mediterranean Sea, Sternaspis affinis Stimpson, 1864 from the Northeastern Pacific, Sternaspis africana Augener, 1918, stat. n. from Western Africa, Sternaspis andamanensis sp. n. from the Andaman Sea, Sternaspis costata von Marenzeller, 1879 from Japan, Sternaspis fossor Stimpson, 1853 from the Northwestern Atlantic, Sternaspis islandica Malmgren, 1867 from Iceland, Sternaspis maior Chamberlin, 1919 from the Gulf of California, Sternaspis princeps Selenka, 1885 from New Zealand, Sternaspis rietschi Caullery, 1944 from abyssal depths around Indonesia, Sternaspis scutata (Ranzani, 1817) from the Mediterranean Sea, Sternaspis spinosa Sluiter, 1882 from Indonesia, and Sternaspis thorsoni sp. n. from the Iranian Gulf. Two genera are newly proposed to incorporate the remaining species: Caulleryaspis and Petersenaspis. Caulleryaspis gen. n. is defined by the presence of falcate introvert hooks, seven abdominal segments, and soft shields with sediment particles firmly adhered on them; it includes two species: Caulleryaspis gudmundssoni sp. n. from Iceland and Caulleryaspis laevis (Caullery, 1944) comb. n. from Indonesia. Petersenaspis gen. n. is defined by the presence of spatulate introvert hooks, eight abdominal segments, and stiff shields with poorly defined ribs but no concentric line; it includes Petersenaspis capillata (Nonato, 1966) from Brazil and Petersenaspis palpallatoci sp. n. from the Philippines. Neotypes are proposed for eight species: Sternaspis thalassemoides, Sternaspis affinis, Sternaspis africana, Sternaspis costata, Sternaspis fossor, Sternaspis maior, Sternaspis scutata and Sternaspis spinosa, to stabilize these species-group names, and a lectotype is designated for Sternaspis laevis which is transferred to Caulleryaspis gen. n. The geographic range of most species appears to be much smaller than previously indicated, and for some species additional material in good condition is needed to clarify their distributions. Keys to genera and to all species are also included.     

An abundant LEA protein in the anhydrobiotic midge,PvLEA4, acts as a molecular shield by limiting growth of aggregating protein particles

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Neoplecostomus doceensis: a new loricariid species (Teleostei,Siluriformes) from the rio Doce basin and comments about its putative origin

A new species of Neoplecostomus is described from the rio Doce basin representing the first species of this genus in the basin. The new species is distinguished from its congeners by having enlarged, fleshy folds between dentaries, two or three series of developed papillae anterior to premaxillary teeth and a adipose-fin membrane present, and by lacking enlarged odontodes along snout lateral margins in mature males, a well-developed dorsal-fin spinelet wider than dorsal-fin spine base, lower number of lateral-line figs and developed membrane on the dorsal portion of the first, second and third pelvic-fin branched rays. Additionally, we present a brief discussion of biogeographic scenarios that may explain the distribution of the new species in the rio Doce basin. We suggested that the ancestral lineage of the new species reached the rio Doce from the upper portions of rio Paraná drainages about 3.5 Mya (95% HPD: 1.6–5.5) indicating a colonization route of the N. doceensis ancestral lineage from the south end of Serra do Espinhaço, probably as a result of headwater capture processes between the upper rio Paraná and rio Doce basins.     

Mushrooms for Life among the Jotï in the Venezuelan Guayana

Mushrooms for Life among the Jotï in the Venezuelan Guayana. This paper explores the relevance of mushrooms in mythology and daily life among the Jotï, an indigenous group inhabiting the rain forests of the Venezuelan Guayana. It is reported here how a personal experience of the author in the field stimulated deeper research into the religious symbolism surrounding mushrooms and their role in Jotï cosmology, ritual, and life dynamics. Different categories of mushroom usage are described, including edible, medicinal, and ritual uses. Mushrooms seem to be more important to the Jotï than to most Amazonian groups. Most significantly, certain species of mushrooms are key ingredients in medicinal and ritual preparations used throughout the Jotï life cycle in ways that reflect their worldview and mythology.     

Myosin IIA is required for neurite outgrowth inhibition produced by repulsive guidance molecule

Although myelin-associated neurite outgrowth inhibitors express their effects through RhoA/Rho-kinase, the downstream targets of Rho-kinase remain unknown. We examined the involvement of myosin II, which is one of the downstream targets of Rho-kinase, by using blebbistatin – a specific myosin II inhibitor – and small interfering RNA targeting two myosin II isoforms, namely, MIIA and MIIB. We found that neurite outgrowth inhibition by repulsive guidance molecule (RGMa) was mediated via myosin II, particularly MIIA, in cerebellar granule neurons. RGMa induced myosin light chain (MLC) phosphorylation by a Rho-kinase-dependent mechanism. After spinal cord injury in rats, phosphorylated MLC in axons around the lesion site was up-regulated, and this effect depends on Rho-kinase activity. Further, RGMa-induced F-actin reduction in growth cones and growth cone collapse were mediated by MIIA. We conclude that Rho-kinase-dependent activation of MIIA via MLC phosphorylation induces F-actin reduction and growth cone collapse and the subsequent neurite retraction/outgrowth inhibition triggered by RGMa.