Comparative sperm ultrastructure of twelve leptodactylid frog species with insights into their phylogenetic relationships

The spermatozoa of representatives of three Neotropical frog subfamilies, Leiuperinae, Leptodactylinae and Paratelmatobiinae, were observed using Transmission Electron Microscopy, with the aim of identifying ultrastructural traits that provide insights into the phylogenetic relationships among these anurans, which are currently unclear. In the leiuperines, spermatozoa of Physalaemus albifrons, P. cicada, P. deimaticus and P. feioi were characterized by an acrosomal vesicle covering the subacrosomal cone that was not observed in the spermatozoa of Physalaemus centralis and P. cuvieri. The tail of the spermatozoa of P. albifrons, P. centralis, P. cicada, P. cuvieri, P. deimaticus, and P. feioi presented a long undulating membrane, whereas Engystomops petersi and E. freibergi, which form a sister clade to Physalaemus, had an axial fiber, which were absent in Physalaemus. Other leiuperine, E. puyango had an abaxonemal bulb-like swelling distally to the paraxonemal rod, which were also absent in Physalaemus. These differences support the revalidation of Engystomops as a true taxon, distinct from Physalaemus. The tail of the spermatozoa of E. petersi and E. freibergi was similar to that of Paratelmatobius poecilogaster (Paratelmatobiinae). The spermatozoa of Leptodactylus natalenis (Leptodactylinae) had undulating membrane and axial fiber, in contrast with Adenomera marmorata, which lacked these structures. Morphological differences between A. marmorata and L. natalensis sperm cells appeared to validate the allocation of A. marmorata into a genus distinct from Leptodactylus. Overall, dissimilarities in the spermatozoa of the leptodactylids provided an important phylogenetic signal for the understanding of their taxonomic relationships.     

Cellular organisation of the mature testes and stages of spermiogenesis in Danio rerio (Cyprinidae; Teleostei)--structural and ultrastructural studies

The male gonads of Danio rerio occupy a position typical of the Teleostei species. The structure of the testes corresponds to the anastomosing tubular type with unrestricted spermatogonia and represents a cystic type of spermatogenesis. The results of this study indicate that four distinct stages of cell differentiation can be identified during spermiogenesis. These stages are characterised by chromatin condensation, the development of flagellum, nuclear rotation, the formation of nuclear fossa and the elimination of excess cytoplasm. A round head and the absence of an acrosome characterise the differentiated sperm. The midpiece is short and large, and C-shaped mitochondria form a ring surrounding the initial region of the flagellum. The axoneme shows a 9 + 2 pattern. In the D. rerio spermatozoa the flagellar axis is at an angle of 110° to the nucleus diameter running through the centriole.     

The sperm ultrastructure and spermiogenesis of Tribolium castaneum (Coleoptera: Tenebrionidae) with evidence of cyst degeneration

Previous studies on the spermatogenesis of tenebrionid beetles showed the unusual formation of two antiparallel sperm bundles per cyst. In this work we reported this feature also in Tribolium castaneum using light and transmission electron microscopy. The sperm structure of T. castaneum, similar to other tenebrionids, consists of a three-layered acrosome, an elongated nucleus and a flagellum with a 9 + 9 + 2 axoneme, two accessory bodies and two asymmetric mitochondrial derivatives. The presence of two antiparallel sperm bundles per cyst also in Meloidae and Rhipiphoridae suggests that it is a strong trait synapomorphic for Tenebrionoidea. The huge degeneration of whole sperm cells in several cysts of testes during spermiogenesis is also described.     

Spermiogenesis and sperm ultrastructure of Machilontus sp (Insecta: Archaeognatha) with phylogenetic consideration

The sperm structure of the jumping bristletail Machilontus sp has been described. The species shares several sperm characteristics with other genera of the same order Archaeognatha. During late spermiogenesis the spermatid bends at half of its length with the two limbs closely apposed within the same plasma membrane. The sperm has a helicoidal bi-layered acrosome with a filamentous perforatorium and a long nucleus. The elongated flagellum consists of an axoneme with 9 accessory microtubules external to the 9+2, two rows of conventional mitochondria and two accessory bodies. The accessory bodies are located lateral to the axoneme and are probably responsible for the shifting of the accessory tubules in two opposite groups of 5 and 4 tubules, respectively. These sperm characteristics represent common traits of all Archaeognatha.     

Molecular diversity of Artocarpus champeden (Moraceae): A species endemic to Indonesia

A summary of results obtained in the study of natural products isolated from a Moraceae species Artocarpus champeden is presented. The various classes of 3-prenylflavonoids isolated and the biogenetical correlation between the metabolites are discussed. Some of the flavonoids exhibited strong cytotoxicity against murine leukemia P388 cell lines, suggesting that flavonoids derived from moraceous plants represent a plausible unexplored resource of novel antitumor leads.     

Analysis of some elements in three Chrysolina (Coleoptera, Chrysomelidae) species by EDXRF spectrometry

In this investigation, the concentration levels of potassium, calcium, iron, nickel and cadmium for three Chrysolina species were measured in the region of Erzurum (Turkey) located at latitude 40°17′ north and longitude 41°17′ east. The concentrations measured by energy dispersive X-ray fluorescence (EDXRF) spectrometry were analysed. Photons of 59.5 keV and 5.9 keV emitted, respectively, by an annular ²⁴¹Am and ⁵⁵Fe radioactive source were used to excite the characteristic X-rays of various elements present in the insect samples. These results are presented and discussed in this paper.     

Structural and ultrastructural characterization of male reproductive tracts and spermatozoa in fig wasps of the genus Pegoscapus (Hymenoptera, Chalcidoidea)

The three Pegoscapus species present the same internal reproductive tract features comprising testes with a single testicular tubule, seminal vesicles, vasa deferentia, accessory glands and an ejaculatory duct. The seminal vesicle shows two morphologically distinct portions although they do not resemble the separate chambers found in other Chalcidoidea. The anterior portion of the seminal vesicle shows a prominent epithelium and stores the mature spermatozoa, while the posterior region is formed by a thicker muscular sheath that participates on ejaculation. The sexual maturation in Pegoscapus is achieved at emergence, when the testicular degeneration occurs. The spermatozoa of Pegoscapus reveal a basic structure similar to that of other Chalcidoidea. In Pegoscapus sp1. and Pegoscapus sp2. they present the same features, whereas Pegoscapus tonduzi comprises some different characteristics. It measures approximately 160 μm in Pegoscapus sp1. and Pegoscapus sp2., while in P. tonduzi the spermatozoa measure about 360 μm. The extracellular sheath thickness is another difference among the species. While Pegoscapus sp1. and Pegoscapus sp2. show a thick extracellular sheath, in P. tonduzi this sheath is very thin resulting in a large space intervening between the extracellular sheath and the nucleus. Despite these differences, the three species analyzed share some characteristics that allow the establishment of an identity to the spermatozoon of the genus Pegoscapus: the seminal vesicle not divided in chambers; the absence of acrosomal structures in the spermatozoa; the length of the extracellular sheath; the central microtubules being the firsts to terminate in the sequence of microtubular cutoff at the final axonemal portion.     

Developmental gametophyte morphology of seven species of Thelypteris subg. Cyclosorus (Thelypteridaceae)

The morphogenesis of the sexual phase of seven species of Thelypteris subg. Cyclosorus (Thelypteridaceae) is described and compared. Spores of all species are monolete, ellipsoid and have positive photoblastism. They have Vittaria-type germination, germinal filaments are short and uniseriate, and Aspidium-type development. Adult gametophytes are spatulate-cordiform, and have wide wings with numerous glandular, marginal and superficial hairs. Antheridia have a narrow or widened basal cell, an undivided annular cell, and an opercular cell; antherozoids are liberated through three mechanisms. Archegonia have short necks and four triangular cells on the neck's mouth. The sporophyte's first leaf is lobed, with open dichotomous veins, glandular hairs similar to those of the gametophyte, and anomocytic stomata. Differences observed between the studied species are: spore size; ornamentation of the perispore; germination and emergence periods; size of hairs; developmental period of gametangia; and antherozoid liberation mechanisms through total detachment of the operculum, partial detachment of the operculum, and development of an apical pore through tearing of the operculum. These taxonomically valuable characters, combined with the sporophyte characteristics, can be useful tools in the identification of the species studied to the subg. Cyclosorus.     

The odyssey of Orpheus: The evolution of solo singing

Notated sacred solo song dates from 1,000 B.C. Early secular song exhibits modest vocal demands of chant-like character. Popular song and liturgical solo song share common origins. Western European secular song notation began in the early Medieval Age. Compositional writing for solo voice took a dramatic turn toward virtuosity about 1600. By the mid-17th century, the modern solo voice emerged. “Classical” solo vocal literature is not static but is constantly evolving, requiring skills far in excess of those of speech or of early solo song literature; this is equally the case with ethnomusicological and popular singing styles. Efficient use of the singing instrument is essential to the healthy accomplishment of all of these literatures.     

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.     

Occurrence and ultrastructure of Albugo candida on a new host, Arabis alpina in Saudi Arabia

A population of Arabis alpina (Brassicaceae) growing in Saudi Arabia was observed to be infected for the first time by the Oomycete, Albugo candida. Both conventional chemical fixation and high pressure freezing followed by freeze substitution (HPF/FS) were used to prepare zoosporangia, intercellular hyphae, haustoria, invading host cells and host–parasite interface of A. candida for study with both scanning and transmission electron microscopy. Both fixations gave good preservation of ultrastructural details and data from the two sample types were highly complementary. Scanning electron microscopic observation revealed that mature zoosporangia of A. candida are spherical or ellipsoidal in shape and characterized by a smooth surface and faint terminal secession scar at each end. Transmission electron microscopic observation indicated that coenocytic intercellular hyphae are located in intercellular spaces of host leaf tissue forming haustoria in host mesophyll cell. Each haustorium is connected to intercellular hyphae by a narrow, slender neck which enclosed by a collar as a response of host cell to infection. The cytoplasm of the haustorium contains different organelles characteristic of the Oomycetes. No obvious responses are observed in host cell organelles following infection which may be due to the presence of a compatibility between the host and the Oomycete. Modifications of the host plasma membrane around the haustorium are detected. Many tubular elements were found to be continuous with the extrahaustorial membrane. This appears to be the first report of the presence of these tubular elements in case of A. candida haustoria. These tubular elements may increase membrane surface area and consequently increase the efficacy of nutrients uptake by haustoria from host cell.     

Optical characterization of fourfold (Td)- and sixfold (Oh)-transition-metal species in MgAl2O4:Co by time-resolved spectroscopy

This work investigates the origin of novel visible photoluminescence (PL) bands observed in the spinel MgAl₂O₄:Co²⁺. Besides the well-known fourfold-coordinated Co²⁺(T_d) PL at 670 nm [N.V. Kuleshov, V.P. Mikhailov, V.G. Scherbitsky, P.V. Prokoshin and K.V. Yumashev, J. Lumin. 55 (1993) 265.], a rich structured PL band at 686 nm was also observed that we associate with uncontrolled impurities of sixfold coordinated Cr³⁺(O_h) by time-resolved spectroscopy and lifetime measurements and their variation with temperature. We also show that the lifetime of the Co²⁺(T_d) emission at 670 nm varies from τ=6.7 μs to 780 ns on passing from T=10 to 290 K. This unexpected behaviour for T_d systems is related to the excited-state crossover (⁴T₁↔²E), making the emission band to transform from a narrow-like emission from ²E at low temperature to a broad structureless band from ⁴T₁ at room temperature.     

Morphological and ultrastructural characterization of the alimentary canal in Japanese wax scale (Ceroplastes japonicus Green)

The morphology and ultrastructure of the alimentary canal in the adult female of the Japanese wax scale, Ceroplastes japonicus Green (Hemiptera: Coccoidea: Coccidae), was investigated using light microscopy, scanning electron microscopy and transmission electron microscopy. The results showed that the foregut was subdivided into a sclerotized pharynx and an oesophagus. A pair of salivary glands attached in the middle of the foregut. The loop-shaped midgut was narrow and longer than the foregut and its inner wall lined with a thick layer of epithelia. The hindgut was divided into a narrower ileum and a broader rectum, with the well-developed filter chamber enclosed in the anterior rectum. Malpighian tubules consisted of two brownish-yellow moniliform tubules with pores, approximately 1 μm in diameter, scattered on the outer surface and many spherical crystals inside the tubules.     

Growth, morphology and optical properties of tris(8-hydroxyquinoline)aluminum/zinc oxide hybrid nanowires

Hybrid tris(8-hydroxyquinoline)aluminum/zinc oxide (Alq₃/ZnO) nanowires were successfully grown from a one-step solution method at very low temperature. The transformation of amorphous Alq₃ into α-phase crystalline nanowires was achieved by incorporating a certain weight fraction of crystalline ZnO nanomaterials. A growth mechanism was proposed to validate the formation of crystalline Alq₃-ZnO hybrid nanowires with the help of nucleation initiated by the ZnO nanomaterials, followed by Alq₃ molecular aggregation. Effects of temperature on the evolution of morphologies of hybrid nanowires were examined by the field-emission scanning electron microscopy (FESEM). The photoluminescence (PL) spectra of hybrid nanowires showed a significant threefold enhancement in PL intensity, along with a slight blue-shift emission, when compared to the pure Alq₃ molecules, which were attributed due to the incorporation of crystalline ZnO nanomaterials and also the shielding effect of ZnO nanomaterials to avoid the excimer formation between the Alq₃ molecules in the excited state.     

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.     

Structure of tetraphenylporphyrinatocobalt(II) low-temperature sublimates

Armenian Institute of Applied Chemistry “ARIAK”, Artsakha Ave., Lane 4, Bld. 5, Erevan, 375005, Armeniya. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 62–66, November–December, 1995.     

On the observability of the fieldB (3): Relativistic effects in magneto-optics

It is shown that the novel vacuum fieldB ⁽³⁾ is an experimental observable, and several methods of observation are suggested: these include the pulsed microwave magnetization of a plasma, the optical Aharonov-Bohm effect, and the microwave frequency optical Faraday effect. The effect ofB ⁽³⁾ is presented in the form of relativistically corrected semi-classical theory.     

A Comparative Study of Acoustic Voice Measurements by Means of Dr. Speech and Computerized Speech Lab

In this study, the calculations and results of acoustic voice analysis as calculated by two different analysis systems (Doctor Speech (DRS), Tiger Electronics, Neu-Anspach, Germany, and Computerized Speech Lab (CSL), Kay Elemetrics Corporation, Lincoln Park, NJ) are compared. A group of 120 normal voices was selected for analysis of the objective parameters: fundamental frequency (F(0)), variation of F(0) (F(0)SD), jitter, shimmer, and harmonics-to-noise ratio (HNR). The subject group was a random selection of normal voices of adults. The aim of this comparison was to find determined differences and similarities in data measurements between both systems to make data transfer possible. A significant correlation was found for F(0), HNR, and shimmer relative. The correlation for jitter (relative and absolute) and F(0)SD was weak. DRS and CSL are not comparable in absolute figures, but their judgment against normative data is identical. Further research is necessary to explore the affect on pathological voices or child voices.