Cuticular Structures Research Articles

In Vitro Effects of Streptomyces tyrosinase on the Egg and Adult Worm of Toxocara vitulorum

Several species of streptomycetes, saprophytic bacteria found widely distributed in soil, water and plants, produce bioactive compounds such as intra and extracellular hydrolases including lytic enzymes which reflecting on their importance in the biological control of insects and parasites. This study assessed the in vitro effects of Streptomyces tyrosinase, produced from Streptomyces spp. isolated from Egyptian soil, on animal-parasitic nematode Toxocara vitulorum, in terms of egg development and adult worm's cuticular structure, and as an alternative strategy to alleviate this infection. This study was conducted at the National Research Centre, Egypt in 2018. Five different concentrations of tyrosinase, ranged from 1%-30% were tested against the development of T. vitulorum eggs. The concentration induced the highest inhibitory activity was tested against adult T. vitulorum cuticle, which is essential for the protective and nutritive functions. The results were compared with those observed in the egg development and worm cuticle following incubation in Streptomyces protease (as a reference enzyme). Compared to Streptomyces protease, higher inhibitory activity on T. vitulorum egg development and extreme cuticular alterations of the treated adult worms had been observed following 24 h exposure to Streptomyces tyrosinase. Once the cuticle had been damaged, the enzyme would be able to penetrate deeper into the internal tissues of the nematode and caused more widespread disruption. The current study could offer a promising bio-control agent, Streptomyces tyrosinase, against T. vitulorum alternative to the more expensive synthetic anthelmintics.

Cuticular Structure Proteomics in the Pea Aphid Acyrthosiphon pisum Reveals New Plant Virus Receptor Candidates at the Tip of Maxillary Stylets.

Aphids are phloem-feeding insects known as major pests in agriculture that are able to transmit hundreds of plant viruses. The majority of these viruses, classified as noncirculative, are retained and transported on the inner surface of the cuticle of the needle-like mouthparts while the aphids move from plant to plant. Identification of receptors of viruses within insect vectors is a key challenge because they are promising targets for alternative control strategies. The acrostyle, an organ discovered earlier within the common food/salivary canal at the tip of aphid maxillary stylets, displays proteins at the cuticle–fluid interface, some of which are receptors of noncirculative viruses. To assess the presence of stylet- and acrostyle-specific proteins and identify putative receptors, we have developed a comprehensive comparative analysis of the proteomes of four cuticular anatomical structures of the pea aphid, stylets, antennae, legs, and wings. In addition, we performed systematic immunolabeling detection of the cuticular proteins identified by mass spectrometry in dissected stylets. We thereby establish the first proteome of stylets of an insect and determine the minimal repertoire of the cuticular proteins composing the acrostyle. Most importantly, we propose a short list of plant virus receptor candidates, among which RR-1 proteins are remarkably predominant. The data are available via ProteomeXchange (PXD016517).

Occurrence, ecological function and medical importance of dermestid beetle hastisetae.

Hastisetae are a specific group of detachable setae characterizing the larvae of Megatominae (Coleoptera: Dermestidae), commonly known as carpet and khapra beetles. These setae are located on both thoracic and abdominal tergites and they are the primary defense of the larva against invertebrate predators. According to previous studies, the main purpose of hastisetae is to work as a mechanical obstacle, but they are also capable to block and kill a predator. Hastisetae, single or aggregate, function as an extremely efficient mechanical trap, based on an entangling mechanism of cuticular structures (spines and hairs) and body appendages (antennae, legs and mouthparts). It is believed that this defensive system evolved primarily to contrast predation by invertebrates, however it has been observed that hastisetae may affect vertebrates as well. Although information on the impacts of vertebrate predators of the beetles is lacking, hastisetae have been shown to be a possible threat for human health as an important contaminant of stored products (food and fabric), work and living environment. Review of past and recent literature on dermestid larvae has revealed that despite these structures indicated as one of the distinctive characters in species identification, very little is known about their ultrastructure, evolution and mechanism of action. In the present work, we will provide the state of knowledge on hastisetae in Dermestidae and we will present and discuss future research perspectives intended to bridge the existing knowledge gaps.

Effects of palmitic acid (16:0), hexacosanoic acid (26:0), ethephon and methyl jasmonate on the cuticular wax composition, structure and expression of key gene in the fruits of three pear cultivars.

The chemical composition, crystal morphology and expression levels of associated genes involved in the cuticular wax of three pear cultivars 'Housui', 'Cuiguan' and 'Yuluxiang' after treatment with palmitic acid (PA), hexacosanoic acid (HA), ethephon and methyl jasmonate (Meja) were determined. A total of 59 cuticular wax compounds were detected across all samples. The wax coverage of 'Housui' fruits increased by 71.74, 93.48 and 89.13% after treatment with PA, ethephon and Meja, respectively, and treatment with PA, HA and Meja also increased the wax coverage in 'Cuiguan' (65.33, 20.00 and 21.33% respectively) and in 'Yuluxiang' (38.60, 63.16 and 42.11% respectively) fruits. Heatmap clustering analysis and partial least-squares-discriminate analysis (PLS-DA) also revealed that the different treatments exerted various influences on cuticular wax among the different cultivars. In addition, the wax component coverage and wax crystal structures showed variations among the different cultivars as well as different treatments. Gene expression analysis revealed 11 genes likely to be involved in pear fruit wax synthesis, transport and regulation. Taken together, the results of this study demonstrate that the differences in the cuticular waxes of the fruits of different cultivars after treatment with PA, HA, ethephon or Meja might lead to a better understanding of the regulatory effect of a substrate or elicitor on the composition and deposition of cuticular waxes.

The role of the foregut in digestion in the cricket

The role of the foregut (crop and proventriculus) in mechanical processing of food has received little attention in insects. Using the Australian plague locust (Chortoicetes terminifera) and the black field cricket (Teleogryllus commodus) as models, the role of the crop in processing of wheat or rye grass was examined. Interior cuticular structures (spines) of the foregut were described using light and scanning electron microscopy, with locusts having sclerotised structures and crops of crickets being unsclerotised internally. Muscular bands on the exterior surface of the crop part of the foregut are similar in males of both species, but contractions and movements are more forceful in locusts. Passage rate from the foregut is much faster in locusts (<3 h) than in crickets (>3 h). Water within the crop is reduced compared with the water content of fresh grass within the foregut of locusts, but water is increased in cricket crops. Spines within the crops are small relative to the size of food particles in both species. Some spines of locusts contain metals. The slower passage rate from the crop of crickets may be limited by the proventriculus. Foregut structure and food processing facilitates the generalist diet of crickets, but may restrict locusts to consuming softer grasses.

Well-preserved cuticle of Atherfieldastacus magnus (Decapoda, Glypheida) from the Aptian of Mexico

The cuticle structure of fossil decapod crustaceans is an important tool, not only for palaeocological and taphonomic interpretations, but also as a potential way to characterise systematically genera and even species the cuticle of which has not been severely altered by diagenetic processes. Localities with abundant decapod crustacean remains can be interpreted either as reflecting mass mortality events or just simple accumulations of exuviae, on the basis of completeness and comparison of cuticle structures between specimens of the same species from different localities. Association with anoxic events by microfacies analyses can offer clues to explain the unusual abundance of decapod crustacean remains. This is the case for the Early Cretaceous lobster Atherfieldastacus magnus (M’Coy, 1849), which is found in large numbers in different Lower Cretaceous (mainly Aptian) lithostratigraphic units across the globe. In this case, we document the well-preserved cuticle structure of specimens from the upper Aptian of Chihuahua (Mexico), preserved three-dimensionally, mainly in concretions, which were studied in different transverse sections showing the cuticle in diverse portions of the lobster body. Thin cuticle layers show the typical crustacean cuticular structure that suggest these are corpses preserved in an anoxic environment.

Fossil Podocarpus (Podocarpaceae) from the lower Pliocene of Tengchong, Yunnan Province, China and its biogeographic significance

ABSTRACT Numerous pollens and a few wood fossils with probable affinity to Podocarpus L’Heritier ex Persoon have been discovered from China. However, the leaf fossils of Podocarpus were not well documented. In this study, we describe a new species, Podocarpus pliomacrophyllus sp. nov., from the lower Pliocene of Tengchong, western Yunnan, southwestern China, with detailed cuticular structures. According to gross morphology and cuticular structure of leaves, the present species mostly resembles extant P. macrophyllus (Thunberg) Sweet, which is attributed to the subgenus Foliolatus de Laubenfels. Molecular data support that the genus Podocarpus derived from Gondwana, and the subgenus Foliolatus diverged from the subgenus Podocarpus during the early Miocene. Therefore, the present fossils from Tengchong indicate that the subgenus Foliolatus had spread from India to western Yunnan before the early Pliocene, and then to southeastern China. The Pleistocene glacial events forced Podocarpus to retreat from western Yunnan and the uplifted Hengduan Mountains hindered its reconnection during the subsequent warm interglacials.

Microstructure of the Primary Remex of Owls (Strigiformes)

An electron microscopic study of the microstructure of the primary remiges in owls (Strigiformes) was conducted using 13 species: Nyctea scandiaca, Bubo bubo, Asio otus, Otus scops, O. sunia, Aegolius funereus, Athene noctua, Glaucidium passerinum, Surnia ulula, Strux aluco, S. uralensis, S. nebulosa, and Tyto alba. Owls have a number of species-specific microstructural primary remex characteristics that are taxonomically important. First of all, these are the structural features of the pennaceous barb, which differ markedly not only at the ordinal, but also at the species level: cross-section configuration, pith architectonics in cross- and longitudinal sections, and cuticular barb structures. This work emphasizes that the identified elements are of taxonomic significance only when comparing the specific, strictly analogous sections of the barbs in different bird species. Based on the present study, we conclude that along with the typical elements of feather architectonics characteristic of representatives of other bird orders, the owls show a number of peculiar microstructural features. Thus, as the result of an analysis of the microstructure of the owls primary remex pennaceous barb vanule, the unique features of the distal barbules and the structure of the apical section of the barb with tightly adjacent and elongate proximal and distal barbules could be distinguished. These characteristics are revealed to cause a dense fleecy structure of the vane dorsal surface and the presence of a complex of peculiar “bunches” that form the cleft edge, i.e., the purely specific traits of the owls feather that are not found in representatives of any other bird orders we have investigated.

Analysis of apple epidermis in respect to ontogenic resistanceagainst Venturia inaequalis

In order to understand mechanisms of ontogenic resistance to apple scab, we analyzed various aspects of young and old leaves. We have introduced an apple plants cultivation system where in vitro propagated and rooting explants produce a genetically uniform population of apple (Malus domestica cv. Idared) plants. In this work, we demonstrate that apple plants produced in our cultivation system showed susceptibility to Venturia inaequalis, the cause of apple scab disease in young leaves and resistance in old leaves, which is similar to orchard situation. Our analysis shows that the cessation of epidermal cell expansion and shape formation coincided with the onset of ontogenic resistance in older leaves. Formation of specific cuticular lamellar structures did not coincide with ontogenic resistance onset. Further, chemical composition analysis of wax from young susceptible and old resistant leaves did not reveal specific compounds involved in ontogenic resistance. Differences in homogalacturonan content in cell walls in susceptible and resistant cells as well as decreased methylesterification of pectin in resistant leaves suggest that polysaccharide composition of the cell wall may play a role in mycelium growth and nutrition.

Morphological assessment of the sensilla of the antennal flagellum in different castes of the stingless bee Tetragonisca fiebrigi

AbstractThe antennae of the insects have cuticular structures called sensilla that play a pivotal role in the perception of stimuli and in communication. The morphology of antennal sensilla has been characterized in eusocial bees; however, there is little information on bees of the genus Tetragonisca. Using scanning electron microscopy, 11 types of antennal sensilla were identified in Tetragonisca fiebrigi: trichodea (ST, subtypes I‐VI), placodea, basiconica, coeloconica, ampullacea, and campaniformia. The largest diversity of sensilla was observed in females. The STI was the most abundant, followed by the placodea and the STII. The STI and the sensila placodea were more abundant in males than females, while the STII were more abundant in workers. Significant differences were found in the length of the different types of sensilla among the classes of individuals, with these differences being greater for the STI in males and the STV in queen; for the STII, STIII, and STIV in queen and workers; and for sensila placodea in queens, workers, and soldiers. Multivariate analysis (PCA and UPGMA) showed that the soldier subcaste was separated from the other females. This study advanced our understanding of sensilla morphology, including the number and distribution of sensilla across sexes and castes, and the sensory structures of T. fiebrigi. The results presented provide relevant information for elucidating the communication mechanisms of social insects.

Early Alterations of Endothelial Nitric Oxide Synthase Expression Patterns in the Guinea Pig Cochlea After Noise Exposure

Constitutively expressed endothelial nitric oxide synthase (eNOS) is supposed to play a role in noise-induced nitric oxide (NO)-production. It is commonly known that intense noise exposure results in inducible NOS (iNOS) expression and increased NO-production, but knowledge about a contribution of the eNOS isoform is still lacking. Effects of noise exposure on eNOS immunolabeling were determined in male guinea pigs (n=24). For light microscopic analysis, 11 animals were exposed to 90 dB for 1 hr and 6 animals were used as controls. After exposure, eNOS immunostaining was performed on paraffin sections, and the staining intensities were quantified for 4 cochlear regions. For electron microscopic analysis, 2 animals were exposed for 2 hr to 90 dB and 5 animals were used as controls. The intensity of eNOS immunolabeling was found to be already comprehensively increased 1 hr after noise exposure to 90 dB. At the ultrastructural level, a clear increase in eNOS immunolabeling was found in microtubules-rich areas of cochlear cuticular structures. Hence, our findings indicate that the reticular lamina forming the endolymph-perilymph barrier at the apical side of the organ of Corti is involved in a fast intrinsic otoprotective mechanism of the cochlea.

Comparative morphology of stridulating setae of Theraphosinae (Araneae: Theraphosidae)

Theraphosid spiders are repleted with cuticular structures that evolved into distinct morphologies and developed different functions. The stridulatory apparatus present in the subfamily Theraphosinae is composed by a group of setae and opposed organs (ridged surface) that emit sound through friction. Only sixteen genera of Theraphosinae spiders were reported with stridulatory setae: Acanthoscurria, Aguapanela, Brachypelma, Citharacanthus, Cyrtopholis, Grammostola, Hemirrhagus, Lasiodora, Longilyra, Nhandu, Theraphosa, Pamphobeteus, Phormictopus, Proshapalopus, Pterinopelma and Vitalius. Besides these stridulating setae, other cuticular structures have been traditionally used in Theraphosinae taxonomy: the plumose scopula on the lateral faces of femora I and IV. However, the ultrastructure of these setae and scopulae was never studied in detail. Here, we analyzed the diversity of cuticular structures on coxae, trochanters and femora of Theraphosinae spiders using SEM. Beside the description of plumose and claviform stridulating setae on femora, we established five distinct variations of stridulatory setae found on coxae and trochanters and report their presence for the genus Megaphobema, Crassicrus and Cotztetlana for the first time.

The role of sex and temperature in melanin-based immune function

Sex differences in immunity have been observed across a wide range of species. Still, it remains unclear how sex-specific interactions with the environment are linked to sex differences in immunity. We studied the plasticity of immunological sex differences by focusing on melanin-based traits in the Pacific field cricket (Teleogryllus oceanicus (Le Guillou, 1841)). Insects rely on the pigment melanin for both immune function and coloration of the cuticle; therefore, changes in melanin production for one of these traits may indirectly affect the other. Male crickets use melanized wing structures to chirp. These cuticular structures are missing in females and a songless male morph. Given that the thermal environment influences cuticle melanization, we investigated the interactive effects of sex and developmental temperature on melanin-based immunity. Both immunity and wing cuticle melanism were reduced in individuals that developed under warmer temperatures. Rearing temperature also mediated the extent to which the sexes differed in immune traits. Males had darker cuticles, whereas females expressed greater immune activity, suggesting that sex-specific investment in melanin corresponds with sex differences in immunity. However, the lack of immunological differences between the two male morphs does not support the hypothesis that investment in cuticle melanism affects investment in immunity.

Umaltolepis and associated Pseudotorellia leaves from the Middle Jurassic of Yima in Henan Province, Central China

The seed-bearing structure Umaltolepis is considered to be produced by the same plants of Pseudotorellia leaves based on their close association in the same fossil bearing horizon and similarities in their cuticles, especially in stomatal structures. In this paper we describe new material of Umaltolepis and Pseudotorellia from the Middle Jurassic Yima Formation in Yima, Henan Province, Central China. Umaltolepis yimaensis sp. nov. is an umbrella-like, ovate to elliptical, four-lobed cupule. The cupule lobes are resinous with thick outer cuticle, and scattered, more or less longitudinally oriented stomata. Leaves of Pseudotorellia yimaensis sp. nov. are narrowly oblanceolate, with two veins entering leaf base and dichotomizing once or twice to produce 4–6 parallel veins that converge and join together near leaf apex. The leaves have fusiform resin bodies between neighboring veins, and thick cuticles with scattered, longitudinally oriented stomata on the abaxial side. The stomata of U. yimaensis and P. yimaensis are very similar, both consisting of sunken guard cells surrounding by specialized lateral subsidiary cells and unspecialized polar cells, and both have two bow-shaped cuticular ridges flanking the stomatal pit and a butter-fly like flange between guard and subsidiary cells. The co-occurrence of U. yimaensis and P. yimaensis in the Yima Formation and their similarities in cuticular structures and in the presence of resin bodies further confirm that Umaltolepis and Pseudotorellia are produced by the same group of plants. These fossils also provide new evidence for a high diversity of ginkgophyte reproductive organs in the Middle Jurassic of Central China.

A new genus and species of Stygarctidae (Heterotardigrada: Arthrotardigrada) from Yaku-Shin-Sone bank (Northwest Pacific)

A marine armoured tardigrade, Hansenarctus toyoshiomaruae gen. et sp. nov., is described from Yaku-Shin-Sone bank, south of Yakushima island, Northwest Pacific. It belongs to the family Stygarctidae Schulz, 1951 for its five-lobed head, cuticular plates, and non-digitate claws, but a combination of the following character states warrants the erection of the new genus: the semi-globular secondary clavae, sub-divided lateral lobes of the head, antero-dorsal, postero-dorsal, and latero-dorsal processes on the dorsal plates except for the caudal plate, two tapering lateral processes (one pair) on each body plate, four lateral processes (two pairs) on the caudal plate, intersegmental regions between dorsal plates, looped seminal receptacles without additional cuticular structures at the openings, and four claws with the internal ones bearing dorsal spurs. Its phylogenetic position is briefly discussed based on morphology and the following topology was suggested for Stygarctidae: (Megastygarctides, (Neostygarctus, (Faroestygarctus, Hansenarctus gen. nov., (Mesostygarctus, Pseudostygarctus), (Parastygarctus, Prostygarctus, Stygarctus)))). Stygarctid genera (excluding Megastygarctides and Neostygarctus) share a synapomorphic state: the presence of exteriorly projected apophyses in the pharyngeal bulb.

The enigmatic kinorhynch Cateria styx Gerlach, 1956 – A sticky son of a beach

Since its discovery in the mid-1950'ies, Cateria has been an enigmatic kinorhynch genus due to its aberrant worm-like shape and extremely thin cuticle. However, the rare occurrence of the species, only found in sandy intertidal habitats, and the poor preservation of the type material have hampered detailed studies of the genus over time. Now, sixty years after the original description of Cateria styx, we present an extensive morphological and functional study based on new material collected from its type locality in Macaé, Brazil. We combine live observations with detailed scanning electron microscopy data, new light microscopy material, confocal laser scanning microscopy and three-dimensional rendering. These observations show that C. styx displays a complex array of cuticular structures (spines, spinoscalids and extraordinarily complex cuticular ornamentation) that we interpret to be adaptations for mechanical adhesion, through friction and interlocking, in an interstitial habitat; the enigmatic dorsal organ, is a hydrostatic structure which function is inferred to be adhesive. Additional morphological traits in C. styx include: extremely elongated primary spinoscalids that cannot be completely retracted in the trunk; a reduced number of spinoscalids; sixteen elongated hairy patches in the introvert; fifteen trichoscalids that vary in length; the absence of a neck; dorsal spines being alternatingly displaced to either left or right side paradorsal positions; and high intraspecific variation in the number and position of glandular openings in the trunk.

Cuticular and Medullary Structure of Some Wild Herbivoresof India

The dorsal guard hair is considered as a mammalian exoskeleton. The anatomical feature of the three concentric layers of the mammalian hair, viz., medulla, cortex, and cuticle vary considerably with different species. The characteristics features of cuticular scales and medullary pattern can be used as an important tool for species identification by using various methods for hair analysis. The morphological features of cuticle and medulla of dorsal guard hair samples of Sambar (Rusa unicolor), Nilgai/blue bull (Boselaphus tragocamelus) and Spotted deer (Axix axis), six each, were studied during post-mortem examination. The microscopic studies showed a difference in some of the cuticular scale and medullar cells among three species. Hence, a single morphological feature of hair may not be a confirmative tool for species identification but multiple morphological features can be used as a confirmative tool of species identification. This study provides pictographic details in eead of some wild species which can be used to curb criminal acts against wild animals.

Meschia zoui sp. nov., first representative of the family Meschiidae from China (Hemiptera: Heteroptera: Lygaeoidea).

All the species of the family Meschiidae, known until now only from India and Australia, are reviewed. A new species, Meschia zoui sp. nov. from southern China, is described as the first representative of this family from China, also its cuticular structures are studied using the scanning electron microscope. A key to all species of Meschiidae is provided, along with a re-description of Meschia quadrimaculata Distant.

Neuroanatomy of mud dragons: a comprehensive view of the nervous system in Echinoderes (Kinorhyncha) by confocal laser scanning microscopy.

BackgroundThe Scalidophora (Kinorhyncha, Loricifera and Priapulida) have an important phylogenetic position as early branching ecdysozoans, yet the architecture of their nervous organ systems is notably underinvestigated. Without such information, and in the absence of a stable phylogenetic context, we are inhibited from producing adequate hypotheses about the evolution and diversification of ecdysozoan nervous systems. Here, we utilize confocal laser scanning microscopy to characterize serotonergic, tubulinergic and FMRFamidergic immunoreactivity patterns in a comparative neuroanatomical study with three species of Echinoderes, the most speciose, abundant and diverse genus within Kinorhyncha.ResultsNeuroanatomy in Echinoderes as revealed by acetylated α-tubulin immunoreactivity includes a circumpharyngeal brain and ten neurite bundles in the head region that converge into five longitudinal nerves within the trunk. The ventral nerve cord is ganglionated, emerging from the brain with two connectives that converge in trunk segments 2–3, and diverge again within segment 8. The longitudinal nerves and ventral nerve cord are connected by two transverse neurites in segments 2–9. Differences among species correlate with the number, position and innervation of cuticular structures along the body. Patterns of serotoninergic and FMRFamidergic immunoreactivity correlate with the position of the brain neuropil and the ventral nerve cord. Distinct serotonergic and FMRFamidergic somata are associated with the brain neuropil and specific trunk segments along the ventral nerve cord.ConclusionsNeural architecture is highly conserved across all three species, suggesting that our results reveal a pattern that is common to more than 40% of the species within Kinorhyncha. The nervous system of Echinoderes is segmented along most of the trunk; however, posterior trunk segments exhibit modifications that are likely associated with sensorial, motor or reproductive functions. Although all kinorhynchs show some evidence of an externally segmented trunk, it is unclear whether external segmentation matches internal segmentation of nervous and muscular organ systems across Kinorhyncha, as we observed in Echinoderes. The neuroanatomical data provided in this study not only expand the limited knowledge on kinorhynch nervous systems but also establish a comparative morphological framework within Scalidophora that will support broader inferences about the evolution of neural architecture among the deepest branching lineages of the Ecdysozoa.

The Root Cap Cuticle: A Cell Wall Structure for Seedling Establishment and Lateral Root Formation

The root cap surrounding the tip of plant roots is thought to protect the delicate stem cells in the root meristem. We discovered that the first layer of root cap cells is covered by an electron-opaque cell wall modification resembling a plant cuticle. Cuticles are polyester-based protective structures considered exclusive to aerial plant organs. Mutations in cutin biosynthesis genes affect the composition and ultrastructure of this cuticular structure, confirming its cutin-like characteristics. Strikingly, targeted degradation of the root cap cuticle causesa hypersensitivity to abiotic stresses during seedling establishment. Furthermore, lateral root primordia also display a cuticle that, when defective, causes delayed outgrowth and organ deformations, suggesting that it facilitates lateral root emergence. Our results show that the previously unrecognized root cap cuticle protects the root meristem during the critical phase of seedling establishment and promotes the efficient formation of lateral roots.