Structure Of Appendages Research Articles

The larva of Siagona europaea Dejean, 1826: Morphology and collecting technique for a subterranean blind ‘running ant killer’ (Coleoptera, Carabidae)

The larva of Siagona europaea Dejean, 1826 collected in the field with a new type of trap, the bait trap, is described. As an adult, this is a myrmecophagous beetle; however, until 2003, in ten years of research no larvae had been found in the field when excavating deep holes around Messor nests in clay soils, in which to place the usually employed pit fall traps. Therefore, a new type of trap was adopted, i.e. a subterranean trap positioned where the main soil crevices intersect. One larva of second instar and one of third one were studied. Most larval features are atypical of carabid beetle larvae and, in particular, the form and structure of the head appendages and the form and insertion of the urogomphi are of interest. Moreover, the larva of S. europaea is completely blind, no trace of stemmata being present in either instar. Its morphology, as well as the recording of its behaviour in the lab, point to it being a ‘runner’, exploring the subterranean crack system of clay vertisols.

Histological approaches for high-quality imaging of zooplanktonic organisms

The investigation of the internal organization of zooplankton communities provides important information on the plankton biology with special interest for the study of ecological processes. Zooplanktoners can play a structural function as indicators for ecosystem health or stress, but their study using histological techniques is still limited. Here we report that the internal structure of zooplanktonic organisms can be facilely observed by a histological approach that combines optimal fixation and processing with a plastic resin (glycol methacrylate) embedding, resulting in increased tissue resolution. Using copepods, organisms that can dominate zooplankton assemblages, as models, collected from a tropical ecosystem (Paraibuna river, Brazil), we showed fine histological details of their muscular, nervous and digestive systems, structure of appendages and cell features. Critical advantages of this approach are that it permits optimal preservation and adequate handling of the organisms (embedded in agar after fixation) for further histological processing and investigation. This is important because it prevents both mechanically induced artifacts and loss of these diminutive organisms during the different steps of processing. Moreover, embedding in plastic resin showed a superior imaging of copepod internal structures compared to paraffin embedding. The use of glycol methacrylate is advantageous over paraffin/paraplast embedding by avoiding heat damage, tissue retraction and allowing faster embedding procedure and better tissue resolution. The value of histological approaches in enabling high-quality imaging of the internal structure of copepods is particularly important because these organisms can be used as indicators of environmental changes.

Clostridium taeniosporum spore ribbon‐like appendage structure, composition and genes

Clostridium taeniosporum spores have about 12 large, flat, ribbon-like appendages attached through a common trunk at one spore pole to a previously unknown surface layer outside the coat that is proposed to be called the 'encasement'. Appendages are about 4.5 microm long, 0.5 microm wide and 30 nm thick and taper at the attachment end into a semicircle that is twisted relative to the flat ribbon. Individual fibrils, about 45 nm in length with spherical heads and long thin tails, form a hair-like nap, visible along the appendage edge. Four appendage proteins have been detected: a paralogous pair of 29 kDa (designated P29a and P29b), a glycoprotein of about 37 kDa (designated GP85) and an orthologue of the Bacillus spore morphogenetic protein SpoVM. The P29 proteins consist of duplicated regions and each region includes a domain of unknown function 11. The GP85 glycoprotein contains a collagen-like region. The genes for P29a and b, GP85 and possibly related proteins are closely linked on two small chromosome fragments. Putative sigma(K)-dependent promoters upstream of the P29a and b genes indicate that they likely are expressed late in the mother cell, consistent with their deposition into the layer external to the coat.

Tale of two tails: The tip of the atrial appendages is an unusual site for focal atrial tachycardia

Focal atrial tachycardias arise predominantly from a small number of atrial anatomic structures.1–3 Atrial tachycardias originating from the atrial appendages are uncommon in normal atria and usually arise from the mouth (base).4,5 Rare instances of atrial tachycardias in association with aneurysms of the atrial appendages6–8 and venous anomalies overlying the left atrial appendage structure have been described.9 Although atrial appendage resection has been described as a curative procedure,10,11 focal atrial tachycardias arising from the distal tip of the atrial appendages successfully treated by radiofrequency (RF) ablation have not been reported.

A new specimen ofWeinbergina opitzi (Chelicerata: Xiphosura) from the Lower Devonian Hunsriick Slate, Germany

A new specimen of the synziphosurine arthropodWeinbergina opitzi is described from the Lower Devonian (Lower Emsian) Hunsruck Slate of Germany (Rhenish Slate Mountains). It is the smallest and only the fifth specimen of this taxon to be described and is preserved in ventral aspect with exceptional preservation of prosomal and opisthosomal appendages. This specimen confirms the presence of a seventh appendage, similar in morphology to the preceding prosomal appendages, associated with opisthosomal segment one. In addition, at least three opisthosomal plates fringed with teeth are confirmed. Correlation of prosomal appendage podomeres betweenWeinbergina and selected chelicerate taxa shows that appendage structure is most similar to eurypterid appendages III–IV and Araneae appendages III–VI. This is in contrast to modern horseshoe crabs which have fewer podomeres in appendages II–V due to an undifferentiated tibiotarsus.

A new species of Catinia Bocquet & Stock, 1957 (Copepoda, Catiniidae) associated with mud shrimps, Axianassa australis Rodrigues & Shimizu, 1992 (Decapoda, Thalassinidea, Laomediidae), from Brazil

Catinia aiso sp. n. was found in association with the mud shrimp, Axianassa australis Rodrigues & Shimizu, 1992 collected in the intertidal zone of Araçá Beach, state of São Paulo, Brazil (23°48’50’’S, 45°23’48’’W). The new species shares with Catinia plana Bocquet & Stock, 1957 the structure of the oral appendages, the setal formula of the swimming legs, the robust pedunculate sucker on the antenna, and the absence of the maxilliped in adult females. However, the two species can be separated by the rostrum shape, the presence or absence of an inner coxal seta on leg 4, and the structure of leg 5 in both sexes. Catinia aiso also differs from C. plana in the depressed ovoid body shape, the ornamentation of the maxilla in the female and in the modified claw of the maxilliped of the male. The sexual dimorphism expressed in the armature of the antennule and the endopodal segments of the swimming legs in C. plana, is absent in C. aiso. This is the first record of Catinia since the genus was established on the basis of material from the Baie de Morgat, France, in 1957.

Formation of a novel surface structure encoded by Salmonella Pathogenicity Island 2

The type III secretion system (T3SS) encoded by Salmonella Pathogenicity Island 2 (SPI2) is essential for virulence and intracellular proliferation of Salmonella enterica. We have previously identified SPI2-encoded proteins that are secreted and function as a translocon for the injection of effector proteins. Here, we describe the formation of a novel SPI2-dependent appendage structure in vitro as well as on the surface of bacteria that reside inside a vacuole of infected host cells. In contrast to the T3SS of other pathogens, the translocon encoded by SPI2 is only present singly or in few copies at one pole of the bacterial cell. Under in vitro conditions, appendages are composed of a filamentous needle-like structure with a diameter of 10 nm that was sheathed with secreted protein. The formation of the appendage in vitro is dependent on acidic media conditions. We analyzed SPI2-encoded appendages in infected cells and observed that acidic vacuolar pH was not required for induction of SPI2 gene expression, but was essential for the assembly of these structures and their function as translocon for delivery of effector proteins.

Homology and homoeomorphy in ostracod limbs

The functional modifications of myodocopan and podocopan ostracod limbs constitute a rich data set with which to carry out phylogenetic analyses, but efforts are hindered by lack of consensus on homologies. Homoeomorphy presents particular difficulties; for example, the furca is post-anal in Myodocopa but pre-anal in Podocopa, suggesting homoeomorphy, not homology. Homoeomorphies also exist between ostracod appendages and those of other Crustacea, for example the oral cone and styliform mandibulae of Paradoxostomatidae (Ostracoda) and Siphonostomatoida (Copepoda), both adaptations to commensal or parasitic lifestyles. Such clear manifestations of homoeomorphy, arising independently in different lineages as a result of similar functional requirements imposed on plesiomorphic appendage structures, warn of the possibility of more subtle examples which, if unrecognized, would lead to misinterpretations of character states used in phylogenetic analysis. For instance, the branchial plates found on third, fourth and fifth limbs of podocopans may not be homologous with the branchial plates on the fifth and sixth limbs of myodocopans. Limb homologies of podocopan ostracods (primarily as represented by various podocopid taxa) are investigated. Evidence is presented, based on studies of morphology and musculature, that podocopid branchial plates are exopodites (arising from the basis), while those of myodocopans are epipodites (arising from the coxa or precoxa). In Podocopida, moreover, the protopodites of post-mandibular limbs appear to be undifferentiated, comprising only a basis, while those of Myodocopa clearly exhibit a basis, coxa and often a precoxa. These differences argue against monophyly of the Ostracoda. The absence of epipodites, combined with the lack of a coxa in post-mandibular limbs, is potentially indicative of closer affinities between podocopans and Cambrian stem-group crustaceans (including Phosphatocopida) than between podocopans and myodocopans. The possible derivation of podocopid third, fourth and fifth limbs from a stem-group crustacean limb is demonstrated. The hypothesis is advanced that podocopan ostracods (represented today by Podocopida, Platycopida and Palaeocopida) are derived from much nearer the base of the crown-group Crustacea than myodocopans.

Stimulation of keratinocyte differentiation – a new role for the vanilloid receptor subtype 1 (VR1/TRPV1)?

Vanilloids and endogenous cannabinoids mediate their actions via the vanilloid receptor subtype 1 (VR1/TRPV1), a non‐selective cation channel, which is widely distributed in the central and peripheral nervous system. Only recently, VR1 has been shown to be expressed in keratinocytes in vitro and in vivo. However, a precise description of VR1 localization in epithelial cells was missing. To determine this, we investigated VR1‐immunoreactivity as well as mRNA and protein expression in a series of biopsies from normal, diseased, and capsaicin‐treated human skin. VR1 was found in epidermal keratinocytes, the inner root sheet and the infundibulum of hair follicles, differentiated sebocytes, sweat gland ducts, and the secretory portion of eccrine sweat glands upon immunohistochemistry, RT‐PCR and Western blot analysis. Interestingly, in diseased skin such as prurigo nodularis, psoriasis vulgaris, and atopic dermatitis, VR1 expression in keratinocytes correlated with the degree of epidermal differentiation. Enhanced VR1 immunoreactivity and protein content was found in prurigo nodularis in which epidermal keratinocytes are highly differentiated. Under effective capsaicin therapy of prurigo nodularis, the epidermis thinned and the distribution pattern of VR1 on epidermal keratinocytes normalized. In psoriasis vulgaris, a disease with disturbed epidermal differentiation, less intense immunostaining for VR1 was observed. This could be confirmed by western blot analysis showing less VR1 protein amount in comparison to prurigo nodularis although histologically both showed a thickened epidermis. In atopic dermatitis, which is characterized by a moderate epidermal hyperplasia only and regular differentiated keratinocytes, VR1 immunoreactivity was unchanged in comparison to normal skin. These findings suggest that VR1 may contribute to regular differentiation of keratinocytes. VR1 activation opens non‐selective cation channels with high permeability to calcium, a ion that is crucially important for the synthesis of cornification proteins such as involucrin, fillagrin and loricrin. The role of VR1 in other epithelial cells of appendage structures remains to be determined. In summary, VR1 is widely distributed in the skin suggesting a central role for this receptor not only in nociception but also maturation and function of epithelial cells.

Dermal choristoma of nasopharynx

The dermal choristoma of the nasopharynx is a developmental tumor that has been reported under a variety of different terms, including accessory auricle, hairy polyp, and dermoid. Although the majority of these lesions arise from the vault of the nasopharynx near the region of the eustachian tube orifice, they have also been reported to arise within the eustachian tube itself, from the nasopharyngeal surface of the soft palate, the oropharynx in the tonsillar region, and, rarely, in the middle ear and mastoid area. We report a case of an otherwise healthy 15-month-old female who presented with a 1-year history of right-sided clear rhinorrhea. Nasopharyngoscopy revealed a 1-cm firm, pinkish-white, smooth-surfaced, spherical, pedunculated mass arising from the left nasopharyngeal wall. The left-sided lesion acted as a ball valve to produce intermittent right-sided obstruction of the nasal passage. Imaging studies demonstrated a homogenous solid mass of the density of adipose tissue. It was excised without complication using cautery. Histopathologic examination revealed a solid mass of fibroadipose tissue that was surfaced by essentially normal skin. The keratinized stratified squamous epithelial surface exhibited a granular layer and numerous dermal appendage structures, including hair follicles, sebaceous glands, and sweat glands. The lesion did not exhibit elastic cartilage. These clinical and histologic findings support the diagnosis of dermal choristoma, a lesion that should be included in the differential diagnosis of nasopharyngeal masses in young individuals.

Studies on neotropical Protoneuridae. 15. Amazoneura gen. nov. with description of A. juruaensis sp. nov. (Odonata, Zygoptera)

The genus Amazoneura is erected to contain A. ephippigera (Selys, 1886), A. westfalli (Machado, 2001) and A. juruaensis sp. nov. The new genus is close to Forcepsioneura Lencioni, 1999 but differs from it mainly by the poorly-developed postero-lateral tubercles of the medium prothoracic lobe, by the dark colour of the metepimerum and of the rear of the head. A. juruaensis sp. nov. (holotype male, Acre, Brazil) differs from the other two species of the genus mainly by the structure of the superior anal appendages.

Expression of vanilloid receptor subtype 1 in cutaneous sensory nerve fibers, mast cells, and epithelial cells of appendage structures.

The vanilloid receptor subtype 1 (VR1)/(TRPV1), binding capsaicin, is a non-selective cation channel that recently has been shown in human keratinocytes in vitro and in vivo. However, a description of VR1 localization in other cutaneous compartments in particular cutaneous nerve fibers is still lacking. We therefore investigated VR1 immunoreactivity as well as mRNA and protein expression in a series (n = 26) of normal (n = 7), diseased (n = 13) [prurigo nodularis (PN) (n = 10), generalized pruritus (n = 1), and mastocytosis (n = 2)], and capsaicin-treated human skin (n = 6). VR1 immunoreactivity could be observed in cutaneous sensory nerve fibers, mast cells, epidermal keratinocytes, dermal blood vessels, the inner root sheet and the infundibulum of hair follicles, differentiated sebocytes, sweat gland ducts, and the secretory portion of eccrine sweat glands. Upon reverse transcriptase-polymerase chain reaction and Western blot analysis, VR1 was detected in mast cells and keratinocytes from human skin. In pruritic skin of PN, VR1 expression was highly increased in epidermal keratinocytes and nerve fibers, which was normalized after capsaicin application. During capsaicin therapy, a reduction of neuropeptides (substance P, calcitonin gene-related peptide) was observed. After cessation of capsaicin therapy, neuropeptides re-accumulated in skin nerves. In conclusion, VR1 is widely distributed in the skin, suggesting a major role for this receptor, e.g. in nociception and neurogenic inflammation.

Can ascospore ultrastructure differentiate between the genera Linocarpon and Neolinocarpon and species therein?

Ascospore appendages of two species of Linocarpon and three species of Neolinocarpon are illustrated using electron microscopy. The structure of these appendages can be used to distinguish between species. The ascospore appendages of species in both genera, however, were found to have similar structure. Thus, species of Linocarpon and Neolinocarpon could not be delineated at the generic level based on ascospore appendage structure.

Rhabdomyomatous Multilocular Thymic Cyst

The thymus is the seat of a diverse array of pathologic conditions given its embryologic roots. Multilocular thymic cysts, although well described, are uncommon, and one associated with rhabdomyomatous elements has not been described previously. A 15-year-old boy complained of sudden-onset chest pain of a month’s duration, but was otherwise well. Chest radiographs localized the mass to the anterior mediastinum, arising from the thymus. A computed tomography scan demonstrated the lesion to be a multilocular fluid-containing cyst. A large, 15-cm cyst contiguous with the thymus was removed. Histologic evaluation confirmed a multilocular cyst lined mainly by mucinous epithelium with focal areas of ciliated and squamous lining. A prominent finding was skeletal muscle elements in the form of spider cells, strap-like cells, and foci reminiscent of fetal-type muscle with cross-striations. At the periphery of the cyst, thymic tissue with branching ducts and Hassall corpuscles were noted. No evidence of skin and/or its appendage structures, cartilage, or other differentiated tissue was seen despite generous sampling of the specimen. The muscle elements, most likely, were derived from thymic myoid cells, while the multilocular cyst arose from remnants of the thymomedullary system.

Preparation of water-soluble chitosan/heparin complex and its application as wound healing accelerator

To make effective wound healing accelerator, water-soluble chitosan (WSC)/heparin (CH) complex was prepared using WSC with wound healing ability and heparin with ability to attract or bind growth factor related to wound healing process. Water-soluble CH complex was prepared by the reaction between WSC and heparin, and then, by adding distilled water to it, ointment type with high viscosity was made. To evaluate the wound healing effect, full thickness skin excision was performed on the backs of the rat and then WSC and water-soluble CH complex ointments were applied in the wounds, respectively. After 15 days, gross and histologic examination was performed. Grossly, untreated control group revealed that the wound had well defined margin and was covered by crust. The second group treated with WSC ointment revealed small wound size with less amount of covering crust and ill-defined margin, which appeared to regenerate from margin. The third group treated with water-soluble CH complex ointment appeared to be nearly completely healed. Histology of each group was well correlated to gross findings. The third group shows nearly complete regeneration of appendage structure similar to normal in the dermis in contrast to control and second group with absence and less number of skin appendages, respectively.

Neuraeschna tapajonica sp. n. from the amazonian region of Brazil (Odonata: Aeshnidae)

Neuraeschna tapajonica sp. n. is described and illustrated from a single male (holotype: Itaituba, Pará, Brazil). It is close to N. dentigera Martin, 1909 from which it is distinguished mainly by the structure of the superior appendages.

Scanning electron microscopy of the embryonic development stages of the spiny lobster Jasus frontalis Milne-Edwards, 1836

Summary The present study describes the formation and fine structure of the different appendages during embryogenesis in the spiny lobster Jasus frontalis, as viewed with scanning electron microscopy (SEM). Fresh materials for study were obtained under laboratory conditions, with developing embryos maintained at 17±1.5°C. Seven different stages were defined from spawning to hatching, lasting 69–91 days. The oval shape of the embryos range in major diameter from 602±21.2.μ at the first stage and 717±30.5μ at the seventh stage, increasing the total volume by 66.8%. The results showed numerous similarities to data obtained for other crustacean species, plus several previously unreported features particular to this lobster. The most conspicuous difference with other decapods is the high degree of development of the antennae II and the slight development of the rudimentary abdomen.

Arrangement of the systemic and pulmonary venous components of the atrial chambers in hearts with isomeric atrial appendages.

The morphological definition of atrial chambers, and the determination of atrial laterality, are based on analysis of the structure of the atrial appendages. The systemic and pulmonary venous connections to the heart, nonetheless, are important in the management of patients having isomeric appendages. In this study, therefore, we analysed the morphology of the postero-superior walls of the atrial chambers so as to provide evidence concerning the morphogenetic background of those hearts, and to improve operative management. We reviewed 15 autopsied specimens with isomeric right appendages, and 10 with isomeric left appendages, paying particular attention to the morphology of the systemic and pulmonary venous connections. The postero-superior walls of the atrial chambers can be made up of the atrial body, the systemic venous components, or the pulmonary venous component. We analysed the contributions made by each of these components. The postero-superior walls of the atrial chambers were markedly variable, but could be grouped into five patterns. Bilaterally well-developed systemic venous components and absence of the pulmonary venous component within the hypoplastic atrial body were present in 9 hearts with extracardiac pulmonary venous connections in the setting of right isomerism. Bilaterally well-developed systemic venous components, and a hypoplastic pulmonary venous component within the hypoplastic atrial body, were present in 5 hearts with intracardiac pulmonary venous connections in right isomerism. Bilaterally well-developed systemic venous components, and a hypoplastic pulmonary venous component within the sizable atrial body, were present in 1 heart with an intracardiac pulmonary venous connection in right isomerism. A well-developed pulmonary venous component within the atrial body, and hypoplasia of one systemic venous component, were present in 7 hearts with left isomerism. A well-developed pulmonary venous component within the atrial body, and hypoplasia of bilateral systemic venous components, were present in 3 hearts with left isomerism. The postero-superior walls of the atrial chambers in hearts with isomeric atrial appendages can be analysed on the basis of a compound structure made of bilateral systemic venous components, a central pulmonary venous component, and the body of the atrium. Hearts with isomeric right appendages have absence or hypoplasia of the pulmonary venous component, while hearts with isomeric left appendages have hypoplastic systemic venous components.

Echocardiographic assessment of the left atrial appendage

The left atrial (LA) appendage is a common source of cardiac thrombus formation associated with systemic embolism. Transesophageal echocardiography allows a detailed evaluation of the structure and function of the appendage by two-dimensional imaging and Doppler interrogation of appendage flow. Specific flow patterns, reflecting appendage function, have been characterized for normal sinus rhythm and various abnormal cardiac rhythms. Appendage dysfunction has been associated with LA appendage spontaneous echocardiographic contrast, thrombus formation and thromboembolism. These associations have been studied extensively in patients with atrial fibrillation or atrial flutter, in patients undergoing cardioversion of atrial arrhythmias and in patients with mitral valve disease. The present review summarizes the literature on the echocardiographic assessment of LA appendage structure, function and dysfunction, which has become an integral part of the routine clinical transesophageal echocardiographic examination.

Ultrastructural Studies of Massarina ingoldiana and M. purpurascens

Ascus and ascospore appendage structures can be important characters in delineation of genera. We have therefore examined the ascus and ascospore ultrastructure of Massarina ingoldiana and M. purpurascens, as Massarina is thought to be a heterogeneous genus. The ascus wall of M. ingoldiana is two layered and comparable to M. thalassiae. Ascospores of both species comprise an electron-transparent mesosporium, an electron-dense episporium and an exosporial mucilaginous sheath. In this respect they are similar to the ultrastructure of other Massarina species, and should be maintained in Massarina.