Antimicrobial function of short amidated peptide fragments from the tick‐derived OsDef2 defensin

Previously Os, a 22 amino acid sequence of a defensin from the soft tick Ornithodoros savignyi, was found to kill Gram‐positive and Gram‐negative bacteria at low micromolar concentrations. In this study, we evaluated synthetic peptide analogues of Os for antibacterial activity with an aim to identify minimalized active peptide sequences and in so doing obtain a better understanding of the structural requirements for activity. Out of eight partially overlapping sequences of 10 to 12 residues, only Os(3–12) and Os(11–22) exhibit activity when screened against Gram‐positive and Gram‐negative bacteria. Carboxyamidation of both peptides increased membrane‐mediated activity, although carboxyamidation of Os(11–22) negatively impacted on activity against Staphylococcus aureus. The amidated peptides, Os(3–12)NH₂ and Os(11–22)NH₂, have minimum bactericidal concentrations of 3.3 μM against Escherichia coli. Killing was reached within 10 minutes for Os(3–12)NH₂ and only during the second hour for Os(11–22)NH₂. In an E. coli membrane liposome system, both Os and Os(3–12)NH₂ were identified as membrane disrupting while Os(11–22)NH₂ was less active, indicating that in addition to membrane permeabilization, other targets may be involved in bacterial killing. In contrast to Os, the membrane disruptive effect of Os(3–12)NH₂ did not diminish in the presence of salt. Neither Os nor its amidated derivatives caused human erythrocyte haemolysis. The contrasting killing kinetics and effects of amidation together with structural and liposome leakage data suggest that the 3–12 fragment relies on a membrane disruptive mechanism while the 11–22 fragment involves additional target mechanisms. The salt‐resistant potency of Os(3–12)NH₂ identifies it as a promising candidate for further development.     

Interaction of a novel antimicrobial peptide isolated from the venom of solitary bee Colletes daviesanus with phospholipid vesicles and Escherichia coli cells

The peptide named codesane (COD), consisting of 18 amino acid residues and isolated from the venom of wild bee Colletes daviesanus (Hymenoptera : Colletidae), falls into the category of cationic α‐helical amphipathic antimicrobial peptides. In our investigations, synthetic COD exhibited antimicrobial activity against Gram‐positive and Gram‐negative bacteria and Candida albicans but also noticeable hemolytic activity. COD and its analogs (collectively referred to as CODs) were studied for the mechanism of their action. The interaction of CODs with liposomes led to significant leakage of calcein entrapped in bacterial membrane‐mimicking large unilamellar vesicles made preferentially from anionic phospholipids while no calcein leakage was observed from zwitterionic liposomes mimicking membranes of erythrocytes. The preference of CODs for anionic phospholipids was also established by the blue shift in the tryptophan emission spectra maxima when the interactions of tryptophan‐containing COD analogs with liposomes were examined. Those results were in agreement with the antimicrobial and hemolytic activities of CODs. Moreover, we found that the studied peptides permeated both the outer and inner cytoplasmic membranes of Escherichia coli. This was determined by measuring changes in the fluorescence of probe N‐phenyl‐1‐naphthylamine and detecting cytoplasmic β‐galactosidase released during the interaction of peptides with E. coli cells. Transmission electron microscopy revealed that treatment of E. coli with one of the COD analogs caused leakage of bacterial content mainly from the septal areas of the cells. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

Structure and sensilla of the antennae and mouthparts of Loxocephala perpunctata Jacobi (Hemiptera: Fulgomorpha: Eurybrachidae)

The ultramorphology of the antennae and mouthparts of the adult Loxocephala perpunctata Jacobi was studied through a scanning electron microscope. Seven types of sensilla were found on antennomeres, including a Böhm bristle on the scape, sensillum trichoideum and plaque organ on the pedicel, two subtypes of sensilla chaetica and two subtypes of sensilla campaniformia on these two antennomeres; and Bourgoin's organ with sensory pegs and sensilla basiconicum on the basal bulb of the flagellum. The mouthparts of L. perpunctata are of the typical piercing-sucking type, similar to mouthparts found in other hemipteran insects. In general, six types of sensilla (i.e., four subtypes of sensilla chaetica, sensillum basiconicum, subapical labial sensillum, uniporous peg-like sensillum, multiporous peg-like sensillum and two subtypes of bristle-like sensilla) were detected on different locations of the labium, with the last three, and numerous cuticular processes, present on the labial tip. The potential functions of these sensilla are discussed.     

Adhesion of Plasmodium gallinaceum Ookinetes to the Aedes aegypti Midgut: Sites of Parasite Attachment and Morphological Changes in the Ookinete

Plasmodium gallinaceum ookinetes adhered to Aedes aegypti midgut epithelia when purified ookinetes and isolated midguts were combined in vitro. Ookinetes preferentially bound to the microvillated luminal surface of the midgut, and they seemed to interact with three types of structures on the midgut surface. First, they adhered lo and migrated through a network-like matrix, which we have termed microvilli-associated network, that covers the surface of the microvilli. This network forms on the luminal midgut surface in response to blood or protein meals. Second, the ookinetes bound directly to the microvilli on the surface of the midgut and were occasionally found immersed in the thick microvillar layer. Third, the ookinetes associated with accumulations of vesicular structures found interspersed between the microvillated cells of the midgut. The origin of these vesicular structures is unknown, but they correlated with the surface of midgut cells invaded by ookinetes as observed by TEM. After binding to the midgut. ookinetes underwent extensive morphological changes: they frequently developed one or more annular constrictions, and their surface roughened considerably, suggesting that midgut components remain bound to the parasite surface. Our observations suggest that, in a natural infection, the ookinete interacts in a sequential manner with specific components of the midgut surface. Initial binding to the midgut surface may activate the ookinete and cause morphological changes in preparation for invasion of the midgut cells.     

Body musculature of Beauchampiella eudactylota (Gosse, 1886) (Rotifera: Euchlanidae) with additional new data on its trophi and overall morphology

This study presents the results of confocal laser scanning microscopy and fluorescence‐labelled phalloidin used to visualize the system of body musculature in Beauchampiella eudactylota. Moreover, the poorly known trophi of B. eudactylota are described based on scanning electron microscopy. In total, four paired longitudinal muscles (musculi longitudinales I–IV) and three circular muscles (musculi circulares I–III) were identified. Among these are the musculus longitudinalis ventralis, the musculus longitudinalis dorsalis and the musculus circumpedalis as documented in previous studies for other rotifer species. Compared to other species, B. eudactylota is characterized by the low number of lateral longitudinal muscles and the absence of some longitudinal muscles (musculi longitudinales capitum) and circular muscles (corona sphincter, musculus pars coronalis). Moreover, scanning electron microscopic data on the trophi of B. eudactylota reveal a number of striking similarities to the trophi in some species of Epiphanidae. This suggests that either (1) these similarities represent plesiomorphic characters present both in Epiphanidae and B. eudactylota or (2) they are synapomorphic features of B. eudactylota and some species of Epiphanidae, which would question the monophyly of Euchlanidae.     

纤毛虫念珠异列虫射出胞器的超微结构观察

应用扫描电镜术和透射电镜术显示,纤毛虫念珠异列虫(Anteholosticha monilata)的射出胞器早期发生在细胞质深处,附近有不同类型的囊泡结构。成熟后射出胞器向表膜迁移,结构由不同电子密度片层的体部、结晶状的中心轴杆部和多层膜的帽部组成。受外界刺激时胞器冲破皮层射出,形态呈"蘑菇"状。据上述观察结果推测:该射出胞器具有防御作用,它可能起源于高尔基体活动产生的小泡;在亲缘关系较近的纤毛虫中,其射出胞器可能具有相似的分化特征。     

Ultrastructure and distribution of sensilla on the antennae of female fig wasp Eupristina sp. (Hymenoptera: Agaonidae)

In the species‐specific and obligate mutualism between the fig (Moraceae: Ficus spp.) and its pollinator (Hymenoptera: Agaonidae), the continuity of lifecycle of both partners completely depends on the female pollinator's ability to detect receptive figs. To better understand the chemical location mechanism, we examined the antennae and their sensilla of the female fig pollinator Eupristina sp. using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The antennae of female Eupristina sp. are geniculated, and in total, there were seven types of sensilla found on the antennae: two types of multiporous placoid sensilla (type 1 is sausage‐like and type 2 is rounded), sensilla trichodea (ST), basiconic sensilla (BS), chaetica sensilla (ChS), coeloconic sensilla (CoS), and one specialized sensillum classified as sensillum obscurum (SO). We described external morphology, abundance, distribution, ultrastructure and discussed putative functions. We inferred from their ultrastructures as chemoreceptors that two types of multiporous placoid sensilla, BS and CoS, were innervated by sensory neurons. The aporous type ST, ChS, and SO were not innervated by dendrites which may function as mechanoreceptor/proprioceptor. These results were also discussed in relation to the interaction between Eupristina sp. and its host fig.     

Anatomical and scanning electron microscopic characteristics of the oropharyngeal cavity (tongue,palate and laryngeal entrance) in the southern lapwing (Charadriidae: Vanellus chilensis,Molina 1782)

This investigation aimed to determine the morphological characteristics of the tongue, palate and laryngeal entrance of southern lapwing by gross anatomy and scanning electron microscopy. For this purpose, the organs of three birds were used as material. Numerous densely distributed acicular projections were found on the lingual apex. Papillary crest consisting of sharp conical papillae were observed between the body and root of the tongue. Conical papillae of the lateral border of the papillary crest were triangular in form, and other conical papillae of the papillary crest were shorter in form. There were no papillary projections or papillae on the smooth surfaces of the lingual body and radix. On the median part of the palate, larger conical papillae, which were directed caudally, also surrounded entrance of the choanal cleft. The transversal papillary rows of conical papillae were observed between the rostral and caudal parts of the choanal cleft and on the caudal border of the infundibular cleft. The laryngeal entrance was surrounded by smooth mucosa without conical papillae. However, in the caudal border of the glottic fissure, there was a conical papillary row formed by numerous conical papillae. There were no anatomical differences between female and male birds.     

粉尘螨生殖系统形态学研究

粉尘螨Dermatophagoides farinae是一种重要的医学螨类。本文用光镜和扫描电镜研究了粉尘螨雌雄生殖系统的形态和结构。结果表明：雄性生殖系统由睾丸、输精管、 附腺、射精管、阳茎及附属交配器官组成。睾丸位于血腔末端,不成对,精原细胞、精母细胞和精子依照精子发育的顺序有规则地分布在其内部。雌性生殖系统包括交配孔、囊导管、储精囊、囊导管、卵巢、输卵管、子宫、产卵管及产卵孔,其中卵巢由一个中央营养细胞和围绕其周围的卵母细胞组成。     

Seed morphology and taxonomy of the North African species of Sideritis L. (Lamiaceae)

REJDALI, M., 1990. Seed morphology and taxonomy of the North African species of Sideritis L. (Lamiaceae). Seed morphology data are shown to support data from general morphology and palynology; they can be used for taxonomy at the sectional and specific levels. At times clear differences are apparent at the infraspecific level. Seed sculpturing was found to be of great value for separating taxa at all levels of the hierarchy.     

The musculature of Squatinella rostrum (Milne, 1886) (Rotifera: Lepadellidae) as revealed by confocal laser scanning microscopy with additional new data on its trophi and overall morphology

Wilts, E.F., Wulfken, D., Ahlrichs, W.H. and Martínez Arbizu, P. 2012. The musculature of Squatinella rostrum (Milne, 1886) (Rotifera: Lepadellidae) as revealed by confocal laser scanning microscopy with additional new data on its trophi and overall morphology.—Acta Zoologica (Stockholm) 93 : 14–27. The monogonont rotifer Squatinella rostrum was investigated with light, scanning electron and confocal laser scanning microscopy to reveal new morphological data on its inner and outer anatomy. In total, the visualized somatic musculature displays five paired longitudinal muscles (musculi longitudinales I–V) and nine circular muscles (musculi circulares I–IX). Compared to other species, S. rostrum is characterized by the absence of several longitudinal and circular muscles (e.g. musculus longitudinalis capitis, corona sphincter and pars coronalis). A reconstruction of the mastax musculature revealed a total number of seven paired and two unpaired mastax muscles. Possibly homologous somatic and mastax muscles in other, thus far investigated rotifers are discussed. Moreover, we provide a phylogenetic evaluation of the revealed morphological characters and suggest possible autapomorphic characters supporting Squatinella and Lepadellidae. Finally, we refer to some striking similarities in the morphology, ecology and way of movement of Squatinella and Bryceella that may indicate a closer relationship of both taxa.     

cDNA Cloning and Characterization of a Human Sperm Antigen (SPAG6) with Homology to the Product of the Chlamydomonas PF16 Locus

Serum from an infertile male with high-titer anti-sperm antibodies was used to identify a novel human sperm antigen by screening of a testis expression library. The clone, initially designated Repro-SA-1 (HUGO-approved symbol SPAG6), was found to encode a sequence highly enriched in testis. The deduced amino acid sequence of the full-length cDNA revealed striking homology to the product of the Chlamydomonas reinhardtii PF16 locus, which encodes a protein localized to the central pair of the flagellar axoneme. The human gene encodes 1.8- and 2.8-kb mRNAs highly expressed in testis but not in prostate, ovary, spleen, thymus, small intestine, colon, peripheral blood leukocytes, heart, brain, placenta, liver, muscle, kidney, and pancreas. The gene was mapped to chromosome 10p11.2-p12. Antibodies raised against SPAG6 sequences localized the protein to the tails of permeabilized human sperm. Both the Chlamydomonas protein and SPAG6 contain eight contiguous armadillo repeats, which place them in a family of proteins known to mediate protein-protein interactions. The cloning of the human homologue of the Chlamydomonas PF16 locus provides a new avenue to explore the role of the axoneme central pair in human sperm function.     

天然产物梣酮对粘虫围食膜的影响

【目的】梣酮是从芸香科植物白鲜Diatamnus dasycarpus根皮中分离出的一种化合物, 对试虫表现出胃毒活性。本研究旨在检测梣酮对粘虫Mythimna separata 6龄幼虫中肠围食膜的影响, 从而进一步阐明梣酮的杀虫作用机理。【方法】经活体及离体处理, 通过生化分析和扫描电镜观察等方法, 研究了梣酮处理对粘虫幼虫中肠围食膜糖含量, 蛋白质含量和组分以及围食膜表面结构的影响。【结果】梣酮(20 mg/mL)活体处理降低了粘虫6龄幼虫围食膜的蛋白质含量, 却使糖含量升高。活体(20 mg/mL梣酮)及离体(8 mg/mL梣酮)处理条件下, 围食膜糖含量分别为对照组的1.75倍及2.17倍。SDS-PAGE结果显示, 离体及活体条件下经梣酮处理, 围食膜部分蛋白质降解。围食膜解剖扫描电镜观察表明, 梣酮处理可造成围食膜微纤丝排列紊乱。【结论】天然产物梣酮处理对粘虫中肠围食膜的糖含量及蛋白质含量和组分有影响,且改变了围食膜表面结构。本研究为深入地研究梣酮杀虫作用机理奠定了基础。     

Ultrastructure and distribution of sensilla on the maxillary and labial palps of Chlorophorus caragana (Coleoptera: Cerambycidae)

Chlorophorus caragana is a species of long‐horned beetle that damages Caragana davazamcii Sancz. (Fabales: Papilionaceae) bushes in desert areas in China. The beetles cause substantial damage to local forestry plantations and the environment. Sensilla on the maxillary and labial palps of coleopterans a allow the insects to recognize their host plants. We used scanning and transmission electron microscopy to study the ultrastructure, distribution, and abundance of various sensilla on the maxillary and labial palps of C. caragana. We found four types of sensilla including ten subtypes: one of Böhm's bristles, three of sensilla chaetica, one of digitiform sensilla, and five of sensilla twig basiconica. The types and distribution of the sensilla on the maxillary and labial palps were highly similar between males and females. Finally, this article discusses the functions of the sensilla of related species in recognizing hosts and the significance of gustation studies in the context of the control of C. caragana.     

Respiratory morphology of the Abedus herberti Hidalgo egg chorion (Hemiptera: Belostomatidae)

Although giant water bugs (Hemiptera: Belostomatidae) are large, aquatic insects known for their obligate paternal egg brooding behaviors, little research has focused on the structure of their eggs. The respiratory requirements of developing embryos likely created selection for brooding, so a thorough understanding of the respiratory morphology of belostomatid eggs could help explain how brooding behaviors facilitate embryonic gas exchange. This study used scanning electron microscopy to document the respiratory microstructure of the eggs of Abedus herberti, a back brooding giant water bug. The exochorion is similar to that of other belostomatids in texture and organization except that the respiratory region is confined to the uppermost quarter of the egg. This is the area exposed to the atmosphere by encumbered males. A plastron network made up of densely packed vertical projections demarcates the boundary between the respiratory and nonrespiratory regions of the chorion. The internal chorion is composed of alternate air‐filled and denser layers that likely facilitate the movement of oxygen from the aeropyles at the top of the eggs to the developing embryonic tissues. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Microscopic analysis and seasonality of gemma production in the freshwater red alga Hildenbrandia angolensis (Hildenbrandiales, Rhodophyta)

The development and release of the unique vegetative propagules of the freshwater encrusting alga Hildenbrandia angolensis Welwitsch ex West et West, gemmae, were studied using several different microscopic and histochemical techniques. In addition, the seasonality of gemma production was monitored bimonthly over a 12‐month period in two spring‐fed streams in Texas, USA. Gemmae differentiate within the thallus and are subsequently released from the surface of the crust. Release of the gemmae most likely occurs by digestion of surrounding cells, as suggested by the presence of starch granules and lipid globules in the region between the released gemma and the thallus. The initial separation of the gemmae from the thallus occurs from the sides of the gemma or the bottom, or possibly simultaneously. Contrary to previous studies, we have observed that gemma production occurs endogenously within the thallus of freshwater Hildenbrandia, rather than on the surface of the crust in raised structures. Histochemical tests and electron microscopic examination indicate that the cells of the gemmae contain a large amount of floridean starch. The starch granules frequently form rings surrounding the nuclei of both gemma and thallus cells; a feature infrequently reported for florideophyte red algae. Our seasonality investigations indicate that large fluctuations in gemma production occur over 1 year, but at least some gemma production continues year‐round in the streams examined.     

Morphology of the proboscis of Hubrechtella Juliae (nemertea,pilidiophora): Implications for pilidiophoran monophyly

The proboscis of Hubrechtella juliae was examined using transmission electron microscopy, scanning electron microscopy, and confocal laser scanning microscopy to reveal more features of basal pilidiophoran nemerteans for morphological and phylogenetic analysis. The proboscis glandular epithelium consists of sensory cells and four types of gland cells (granular, bacillary, mucoid, and pseudocnidae‐containing cells) that are not associated with any glandular systems; rod‐shaped pseudocnidae are 15–25 μm in length; the central cilium of the sensory cells is enclosed by two rings of microvilli. The nervous plexus lies in the basal part of glandular epithelium and includes 26–33 (11–12 in juvenile) irregularly anastomosing nerve trunks. The proboscis musculature includes four layers: endothelial circular, inner diagonal, longitudinal, and outer diagonal; inner and outer diagonal muscles consist of noncrossing fibers; in juvenile specimen, the proboscis longitudinal musculature is divided into 7–8 bands. The endothelium consists of apically situated support cells with rudimentary cilia and subapical myocytes. Unique features of Hubrechtella's proboscis include: acentric filaments of the pseudocnidae; absence of tonofilament‐containing support cells; two rings of microvilli around the central cilium of sensory cells; the occurrence of subendothelial diagonal muscles and the lack of an outer diagonal musculature (both states were known only in Baseodiscus species). The significance of these characters for nemertean taxonomy and phylogeny is discussed. The proboscis musculature in H. juliae and most heteronemerteans is bilaterally arranged, which can be considered a possible synapomorphy of Hubrechtellidae + Heteronemertea (= Pilidiophora). J. Morphol. 274:1397–1414, 2013. © 2013 Wiley Periodicals, Inc.     

Morphology and morphometry of the scutellum of six species in the genus Meccus (Hemiptera: Triatominae)

We studied the morphology and morphometry of scutella from six species of the hemipteran genus Meccus to identify new tools to help solve taxonomic problems in closely related insect species of epidemiological relevance. Scutellum samples were observed by scanning electron microscopy and were subjected to morphometric analysis. The results mainly show differences in central depression shape, posterior process, and vestiture. We found significant dimensional differences in scutellum morphometry and a clear sexual dimorphism among species. A combination of morphology and morphometry can be used to differentiate among species of the genus Meccus.     

The source of chilopod sensory information: External structure and distribution of antennal sensilla in Scutigera coleoptrata (chilopoda,Scutigeromorpha)

The investigation of the antennae of Scutigera coleoptrata (Linnaeus, 1758) by scanning electron microscopy (SEM) revealed the presence of five types of sensilla: sensilla trichodea, beak‐like sensilla, cone‐shaped sensilla brachyconica on the terminal article, sensory cones at the antennal nodes, and the shaft organ. Alongside the presence and absence of antennal sensillar types, three unique characters were found in the Scutigeromorpha: the presence of long antennae with nodes bearing sensory cones, the presence of a bipartite shaft including the shaft organ, and the presence of beak‐like sensilla. Neuroanatomical data showed that the animals' brains are equipped with well‐developed primary olfactory and mechanosensory centers, suggesting that the antennae must be equipped with specialized sensilla to perceive chemosensory and mechanosensory cues. With the evidence provided in this article for the Scutigeromorpha, SEM data are available at last on the antennal sensilla for all five chilopod taxa, allowing a comparative discussion of antennal morphology in Chilopoda. J. Morphol., 2011. © 2011Wiley‐Liss, Inc.