Antennal morphology and sensilla ultrastructure of the web-spinning sawfly Acantholyda posticalis Matsumura (Hymenoptera: Pamphiliidae)

Acantholyda posticalis (Hymenoptera: Pamphiliidae) is an important pine pest with a world-wide distribution. To clarify the olfactory receptive mechanism of A. posticalis, scanning electron microscopy and transmission electron microscopy were used to examine the morphology, ultrastructure, and distribution of antennal sensilla of adults from two sites in China. The antennae were filiform, and the flagella comprised 32–35 flagellomeres. Six sensillum types were found. Sensilla chaetica were straight setae with sharply pointed tips and without dendrites in the lumen. Sensilla trichodea were characterized by a parallel-grooved wall and one terminal pore and were innervated by four dendrites at the base. Sensilla basiconica I possessed longitudinally grooved surfaces and multiple terminal pores, with five dendrites in the lumen. Sensilla basiconica II not only had a distinct terminal pore but also had numerous tiny wall pores and many dendritic branches within the sensillum lymph. Sensilla coeloconica had deep longitudinal grooves, one terminal pore and six dendrites, while sensilla campaniformia were thick-walled with a terminal opening and sensory nerve bundles in the lumen. Sensilla chaetica and s. trichodea were most abundant and distributed over the entire antennae, while s. basiconica I and II, s. coeloconica, and s. campaniformia were restricted to the ventral flagellar surfaces. Although the shape and structure of antennae were similar in males and females, females had significantly longer antennae than males, and males had significantly more s. basiconica I than females. We compared the morphology and structure of these sensilla to other Hymenoptera and discussed their possible functions.     

Ultrastructural analysis of spermiogenesis in the Eastern Fence Lizard,Sceloporus undulatus (Squamata: Phrynosomatidae)

Studies on reptilian sperm morphology have shown that variation exists at various taxonomic levels but studies on the ontogeny of variation are rare. Sperm development follows a generalized bauplan that includes acrosome development, nuclear condensation and elongation, and flagellar development. However, minute differences can be observed such as the presence/absence of manchette microtubules, structural organization during nuclear condensation, and presence/absence of a nuclear lacuna. The purpose of this investigation was to examine sperm development within the Sceloporus genus. The process begins with the development of an acrosomal complex from Golgi vesicles followed by nuclear condensation and elongation, which results in the presence of a nuclear lacuna. As the acrosomal complex differentiates, flagellar development commences with elongation of the distal centriole. Spermatid development culminates in a mature spermatid with a highly differentiated acrosomal complex, a condensed nucleus with a nuclear lacuna, and a differentiated flagellum. Although the overall developmental pattern is consistent with other squamate species, minute differences are observed, even within the same genus. For example there is variation in the presence/absence of an endoplasmic reticulum complex during acrosome development, presence/absence of a nuclear lacuna, and presence/absence of manchette microtubules within the three species of Sceloporus studied to date. Future studies concerning sperm morphology in closely related species will aid in our understanding of variation in sperm development and may prove to be useful in testing phylogenetic and evolutionary hypotheses.     

Spermatozoon of the freshwater rotifer Brachionus calyciflorus (Rotifera,Monogononta): Advances in morphological and ultrastructural studies

The morphological and ultrastructural features of the spermatozoon in Brachionus calyciflorus are described using light, fluorescence and transmission electron microscopy (TEM). The mature spermatozoon, which appears to be thread-like, is composed of a slightly expanded anterior of cell body region and a flagellum region without acrosome. The cell body region and flagellum region are respectively 16–27 μm and 20–33 μm in length (n = 60). The spermatozoon is characterized by a mass of dense tubular materials, which occupy most of the cell. Some mitochondria are distributed around the nuclear region in the anterior of the cell body region, while in the posterior portion of cell body, the chromatin often contains a single lobated nucleus arranged at the center of cell. The flagellum contains the classic axoneme (9 × 2 + 2) and possesses lateral undulating membrane. Mature B. calyciflorus males have no germ cell stages earlier than the spermatids in the testis. TEM examination reveals rigid rods as well as predominant typical spermatozoon in the testis. Observations, based on successive photographs and videos, enabled a first-time recording of the unique inverted movement of the spermatozoon, which indicated that the movement of the spermatozoon is driven by the flagellum. Our study also provides further supplementary insights into the phylogenetic systematics of the Rotifera.     

The venom gland of queens of Apis mellifera (Hymenoptera, Apidae): morphology and secretory cycle

The venom gland of queens of Apis mellifera was examined through light and transmission electron microscopy and subjected to electrophoretic analyses. Virgin queens exhibited prismatic secretory cells containing large amounts of rough endoplasmic reticulum with dilated cisternae, open secretory spaces, numerous vacuoles and granules scattered in the cytoplasm, and spherical nuclei with numerous nucleoli. The secretion produced was non-refringent under polarized light and the electrophoretic analysis of glandular extracts revealed five main protein bands. In mated queens, the venom gland exhibited a high degree of degeneration. Its secretion was refringent under polarized light and one of the main bands was absent in the electrophoretic pattern obtained. The morphological aspects observed are in agreement with the function of this gland in queens, given that virgin queens use venom in battles for the dominance of the colony, a situation that occurs as soon as they emerge, while fertilized queens rarely use venom.     

Sperm morphology of Trichospilus diatraeae and Palmistichus elaeisis (Hymenoptera: Chalcidoidea: Eulophidae)

In this study, the sperm morphology of the parasitoids Trichospilus diatraeae and Palmistichus elaeisis (Eulophidae) was investigated using light and transmission electron microscopy. In the two species, the sperm are spiral along their entire length and measure about 130 μm and 195 μm in length, respectively. The head region consists of the acrosome and nucleus. The acrosome is composed of an acrosomal vesicle and, in P. elaeisis, a perforatorium. In both species, an extracellular layer in which several filaments are radiated covers the acrosome and the anterior nuclear region. The nuclei are filled with homogeneous and compact chromatin and measure about 50 μm in length in P. elaeisis and 20 μm in T. diatraeae. The flagellum consists of an axoneme with the 9 + 9 + 2 microtubule arrangement spiraled in a long helix, two mitochondrial derivatives coiling around the axoneme and, in P. elaeisis, two accessory bodies. In T. diatraeae were observed transverse striations throughout the central region of the axoneme, whereas the central pair of microtubules was rarely observed. In the final flagellar region in T. diatraeae, different from P. elaeisis, one mitochondrial derivative ends well before the other and both end before the axoneme. The sperm of these two species exhibit features that discriminate one species from each other, as well as characteristics suggest that Eulophidae is closely related to Trichogrammatidae and both of these families are more similar to Eurytomidae than Agaonidae.     

Temperature induced alterations in the liver of wall lizard (Hemidactylus frenatus): morphological and biochemical parameters

Wall lizards (Hemidactylus frenatus) were adapted to 20, 25, and 30 °C, and the liver was examined using standard transmission electron microscopy (TEM) and biochemical analysis. Peroxisomes were visualized after using the 3,3′-diaminobenzidine (DAB) technique. Catalase, uricase and protein content wsere determined biochemically. The hepatocytes of animals adapted to higher temperature displayed larger lipid inclusions than those of animals adapted to lower temperature. Rough endoplasmic reticulum was better developed in the animals kept at low temperature (20 and 25 °C) than in the animals held at 30 °C. Cytoplasmic crystalline structures were visualized, and better developed in the hepatocytes at 25 °C. Peroxisomes varied with the temperature, being more frequent in the animals kept at 20 °C, while the bigger ones prevailed in the animals kept at 30 °C. The higher catalase activity at higher temperature was correlated to an increase in staining intensity of DAB-incubated peroxisomes as visualized cytochemically in TEM. The biochemical results confirmed the cytochemical reaction observed by TEM. The hepatocytes of the animals at 30 °C showed a reduction in the number of peroxisomes, however, at this temperature the largest peroxisomes with a stronger reaction to DAB and a higher activity of catalase predominate. In contrast, the uricase activity showed no significant variation in relation to adaptation temperature. Overall, these data show the morphological and functional plasticity of hepatocytes to temperature adaptation of H. frenatus.     

Larval ultrastructure of Parasarcophaga dux (Thomson) (Diptera: Sarcophagidae)

Ultrastructure of all larval instars of Parasarcophaga dux (Thomson), a common flesh fly species in Thailand, is presented using scanning electron microscopy. Special attention is given to the structure of anterior and posterior spiracles since these are important features used to differentiate between other sarcophagids. Each anterior spiracle in second and third instars has a single row of papillae varying in number from 14 to 17. The posterior spiracular discs have incomplete peritremes, with a prominent inner arc. Three long, narrow spiracular slits are oriented more or less vertically in each spiracular disc of third instar. Posterior spiracular hairs lack extensive branching and emanate approximately midway down the length of each slit. Microscopic morphology of the mouthhooks markedly differs between the first and second instars. The structure of these mouthhooks supports this fly species as being necrophagous or capable of producing myiasis.     

Ultrasound-assisted acid hydrolysis of cassava (Manihot esculenta) bagasse: Kinetics,acoustic field and structural effects

Improving the actual acid hydrolysis of cassava bagasse (CB) with the assistance of high-intensity ultrasound (US) was aimed in comparison with mechanical agitation (AG). The kinetics of reducing and total sugar release were mathematically modeled. The acoustic field characterization and apparent viscosity of the suspensions were correlated. Moreover, microscopic analyses (visible, fluorescence and polarized light) were carried out to identify changes produced by the treatments. Both AG and US-treatments showed themselves to be effective at hydrolyzing CB. However, US-experiments reached equilibrium in the reducing sugar release process earlier and obtained slightly higher values of total sugars released. The Naik model fitted the experimental data with good accuracy. A greater loss in the birefringence of the starch granules and the degradation of lignocellulosic matter was also observed in US-assisted hydrolysis. The actual acoustic power applied was reduced after hydrolysis, probably due to the increase in the apparent viscosity of the resulting suspensions.     

Ultrastructural aspects of naturally occurring wound in the tunic of two ascidians: Ciona intestinalis and Styela plicata (Tunicata)

Efficient wound healing is essential for all animals from insects to mammals. Ciona intestinalis and Styela plicata are solitary ascidians belonging to urochordates, a subphylum that occupies a key phylogenetic position as it includes the closest relative to vertebrates. Urochordate first physical barrier against invaders is the tunic, an extracellular matrix that is constantly exposed to all kinds of insults. Thus, when damage occurs, an innate immune response is triggered to eliminate impaired tissue and potentially pathogenic microbes, and restore tissue functionality. Ultrastructural aspects of the tunic in the wound healing process of two ascidians are described. In the injured areas, we evidenced thinning of the tunic and areas of low fibre density, dense intratunic bacterial and protozoan population, and inflammatory aspects such as the increase in tunic cells, their aggregates, and phagocytosis. This is the first report on tunic physical wounding occurring in the natural habitat.     

Antennal morphology and sensillar ultrastructure of Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae)

The parasitoid beetle Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is an important parasite of longicorn beetles (Cerambycidae), and has been used in China for the biological control of the Asian longicorn beetle and the Japanese pine sawyer. In this study the antennal morphology and sensillar ultrastructure of D. helophoroides were observed using scanning electron microscopy and transmission electron microscopy. Two types of sensilla trichodea (Tr. 1 and Tr. 2), two types of sensilla basiconica (Ba. 1 and Ba. 2), three types of sensilla chaetica (Ch. 1, Ch. 2 and Ch. 3), and Bohm's bristles were identified according to the morphology and fine structure of each type of sensilla in both sexes. Ultrastructural studies revealed porous structures on the cuticle wall and dendritic branches in the inner lumen of Tr. 1, Tr. 2, Ba. 1, and Ba. 2, thereby suggesting chemoreceptor functions. No difference in shape, structure, sensilla distribution and typology was observed between the sexes. These structures likely have roles in the host locating and habitat searching behavior of adult D. helophoroides, and suggest future studies on the olfaction and host location behavior of D. helophoroides and other coleopteran parasitoids.     

Fat body of Prorhinotermes simplex (Isoptera: Rhinotermitidae): ultrastructure, inter-caste differences and lipid composition

Ultrastructure of the fat body was studied in following castes and developmental stages of Prorhinotermes simplex: larvae of the first and the second instar, pseudergates, presoldiers, soldiers, nymphs, imagoes and mature ergatoid neotenic reproductives of both sexes. Fat body always consists of two principal cell types: adipocytes and urocytes. Adipocytes are characterized by a presence of large amounts of storage substances, namely lipid droplets, glycogen rosettes and proteins in the form of either biocrystals or vacuoles. Proportion of these components strongly varies during ontogeny. Adipocytes are equipped by a large central vacuole in which lipid droplets may resolve. Cytoplasm of urocytes contain glycogen rosettes and spherical or irregular concretions, other organelles are rare. Only adipocytes change their inner structure in the course of ontogeny: amount of glycogen decreases during the postembryonic development, it is the major kind of inclusion in the larvae but lacks in nymphs and imagoes; opposite trend is performed by lipids. The changes in protein content are less obvious but are explained and discussed. The total amount of triacylglycerols (TAGs) was found to be roughly 100microg in a pseudergate, 250microg in a nymph, and 30microg in a soldier. The most abundant fatty acids in TAGs are oleic (O), stearic (S), palmitic (P) and linoleic (L) acid. TAGs form a complex mixture with OOO, OPO, OLO and OOS being the most abundant isomers. Only negligible differences exist among the castes.     

Ultrastructure of germ cells,Sertoli cells and mitochondria during spermatogenesis in mature testis of the Chinese Taihang black goats (Capra hircus)

The objective of this study was to describe the ultrastructure of germ cells, Sertoli cells and mitochondria in mature testis of the Chinese Taihang black goat. The characteristics of germ cell nucleus and mitochondria changing during spermatogenesis were investigated by transmission electron microscopy (TEM). The results showed that the spermatogonium was elliptical, and its nucleus was about 4–5 μm. The round mitochondria can be observed throughout the cytoplasm around the nucleus. Small patches of heterochromatin were distributed throughout the nucleus. Spermatocyte was oval-shaped with a nucleus of about 4–4.5 μm in diameter. The heterochromatin began to attach to the inner surface of the nuclear membrane. Spermatid was about 4 μm and oval in shape. Its nucleus was oval or round and approximately 2–3 μm in diameter. The borderline between nucleus membrane and karyoplasm was distinct. During spermiogenesis, spermatid nucleus was condensed and elongated, and chromatin reached the highest condensation in the mature spermatozoon. The mid-piece was surrounded by mitochondria at the neck region. The sperm tail showed the typical “9 + 2″ structure, contained axoneme and central singlet microtubules. The nuclei of the Sertoli cells were irregular shaped and showed indentations in the membrane. In the mature testes of goat bucks, abundant mitochondria were around the germ cells and Sertoli cells. The scattered mitochondria were aggregated around the base of the flagellum (axoneme) during the spermatid differentiation stage. In conclusion, the present study showed that the spermatogenic process of Taihang black goat followed the pattern of mammals with some specific.     

Structure and ultrastructure of spermatozoa of Chrysomya megacephala (Diptera: Calliphoridae)

The spermatozoa of Chrysomya megacephala are similar to those described for other Brachycera. In this species, the spermatozoa are long and thin, measuring about 590 μm in length, of which the head region measures approximately 60 μm. The head includes a monolayered acrosome with electron-lucid material, and the shape of the nucleus, in cross-sections, varies from circular to oval with completely condensed chromatin. The centriole was observed in the zone of flagellar implantation, below the “peg” region. In the region of overlap, the followings structures are observed: nucleus, centriolar adjunct, mitochondrial derivatives and axoneme. The two mitochondrial derivatives are of different lengths but similar diameter. The axoneme is of a conventional insectan type with a 9 + 9 + 2 microtubular arrangement, with accessory tubules flanked by the electron-dense intertubular material. The male internal reproductive tract consists of testis, vas deferens, seminal vesicle, accessory glands and ejaculatory duct.     

Changes in ultrastructure and histochemistry of two red macroalgae strains of Kappaphycus alvarezii (Rhodophyta, Gigartinales), as a consequence of ultraviolet B radiation exposure

Ultraviolet radiation (UVR) affects macroalgae in many important ways, including reduced growth rate, reduction of primary productivity and changes in cell biology and ultrastructure. Among red macroalgae, Kappaphycus alvarezii is of economic interest by its production of kappa carrageenan. Only a few reports have examined the changes in macroalgae ultrastructure and cell biology resulting from UVB radiation exposure. Therefore, we examined two strains of K. alvarezii (green and red) exposed to UVB for 3 h per day during 28 days and then processed them for histochemical and electron microscopy analysis. Reaction with Toluidine Blue showed an increase in the thickness of the cell wall and Periodic Acid-Schiff stain showed a decrease in the number of starch grains. UVBR also caused changes in the ultrastructure of cortical and subcortical cells, which included increased thickness of the cell wall and number of free ribosomes and plastoglobuli, reduced intracellular spaces, changes in the cell contour, and destruction of chloroplast internal organization. Based on these lines of evidence, it was evident by the ultrastructural changes observed that UVBR negatively affects intertidal macroalgae and, by extension, their economic viability.     

The integumentary ultrastructure of Cryptocellus bordoni Dumitresco and Jurvara-Bals, 1976 (Arachnida,Ricinulei)

Ricinulei is an order of Arachnida composed of rare and little known species. The species of Ricinulei possess a rich variety of fine integumentary structures that have been poorly investigated in a few species. Besides, several structures are still undescribed and their function not yet addressed. In this paper we provide a detailed study of the integumentary morphology of Cryptocellus bordoni Dumitresco and Jurvara-Bals, 1976 using Light and Scanning Electron Microscopy. We describe and present photos of the new and already known fine integumentary structures. We compare the new structures to those previously described for other Ricinulei species and discuss their taxonomic implications and the placement of C. bordoni in the genus Cryptocellus.     

Labral gland in soldiers of the neotropical termite Cornitermes cumulans (Isoptera: Termitidae: Syntermitinae)

Cornitermes cumulans is a termite species of the subfamily Syntermitinae with a nasute mandibulate soldier caste, members of which are morphologically equipped with structures and organs specialized for the defence of the colony. We investigated the labrum of soldiers of C. cumulans and described the labral gland, an exocrine structure present in this appendage. The labrum of C. cumulans soldiers presented two distinct regions, the hyaline tip and the proximal region connected to the head. The hyaline tip exhibited a thick cuticle composed of a loose endocuticle involving an epithelium of class 1 cells, which synthesize the glandular product into a subcuticular space that function as a reservoir prior to release the final secretion. The proximal region of the labrum had an epithelium composed of class 1 and class 3 cells, which released the secretion onto both ventral and dorsal surfaces. The ultrastructure showed abundant smooth endoplasmic reticulum and glycogen in the class 1 cells, whereas the class 3 cells had many electron-lucent vesicles that varied in size. We associated the labral gland with the production of toxic substances that may act inside enemy wounds made by the soldiers’ mandibles. Other possible functions for the labral secretion are also discussed.     

Comparative ultrastructure of spermatozoa of the redclaw Cherax quadricarinatus and the yabby Cherax destructor (Decapoda,Parastacidae)

Ultrastructure of spermatozoa of redclaw Cherax quadricarinatus and yabby Cherax destructor were described and compared. The acrosome complex and nucleus are located at the anterior and posterior region of the spermatozoon, respectively. The acrosome is a complex vesicle divided into two parts: the main body of the acrosome appears as a dense cup-shaped structure in longitudinal sagittal view, with the subacrosome zone occupying the central area of the vesicle. The acrosome is larger in C. quadricarinatus (width 2.37 ± 0.27 μm, length 1.31 ± 0.23 μm) than in C. destructor (width 1.80 ± 0.27 μm, length 1.01 ± 0.15 μm). There was no significant difference in L:W ratios of the studied species. The subacrosome zone in both species consists of two areas of different electron density. The nucleus is substantially decondensed and irregular in shape, with elaborate extended processes. The examined species exhibited a well-conserved structure of crayfish spermatozoon, similar to those of Cherax cainii and Cherax albidus. Small acrosome size, the absence of radial arms, and an extracellular capsule seem to be the morphological features that mostly distinguish Cherax from the Astacidae and Cambaridae.     

Ultrastructure of the mature spermatozoon of the bivalve Scapharca broughtoni (Mollusca: Bivalvia: Arcidae)

The ultrastructure of mature spermatozoa of the giant clam bivalve Scapharca broughtoni was investigated by transmission electron microscopy for the first time. The mature spermatozoon consists of a head which is composed of a cone-shaped acrosome, a round nucleus, and a tail region. A subacrosomal space contains an axial rod and a basal plate, the latter lying between the acrosome and the nucleus. Although the nucleus lacks an anterior invagination, an inverted shallow V-shaped posterior invagination is present within the nucleus. Within the middle portion of the spermatozoon lie five spherical mitochondria while the long whip-like end portion is composed of an axoneme with the typical 9 + 2 structure. Our conclusion is that the spermatozoon of S. broughtoni is of the type I anacrosomal “aquasperm”, and the morphology of acrosome and nucleus are an adaptation to external fertilization.     

The Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae) digestive tract: histology, ultrastructure and its physiological significance

The Sunn pest, Eurygaster integriceps Put. (Hemiptera: Scutelleridae), is a key pest of wheat in the Middle East and some other areas which causes severe qualitative and quantitative damage. The objective of the current work is to describe the morphology of the midgut of E. integriceps adult. Microscopic studies revealed that foregut consists of oral cavity, pharynx and oesophagus likely other phytophagous Hemiptera. In the Midgut, four anatomical regions could be identified: the first ventriculus (V1), the second ventriculus (V2), the third ventriculs (V3), and the fourth ventriculus (V4). The microvilli and perimicrovillar membrane (PMM) were found in V1-V3 regions with columnar cells characterized by presence of mitochondria, rough endoplasmic reticulum and basal infoldings in the basal portion. However, V2 and V3 showed less developed basal plasma membrane infoldings. Three cell types: columnar, endocrine and regenerative cells were found in V1-V3. The V4 region showed different histological features from the other three midgut regions by showing a vacuolated epithelium with crypts storing symbiotic bacteria. The hindgut had a short ileum followed by a well-developed rectum with an epithelial cell layer and a thin cuticular intima. The current results suggest V1-V3 midgut regions play a role in enzyme and absorption, whereas V4 seems to have no function in digestion.