Fine structure of the spermatozoon of <Emphasis Type="Italic">Diopatra neapolitana</Emphasis> (Polychaeta,Onuphidae)

The identification of Diopatra species lacks of clear diagnostic features of taxonomic importance and the knowledge of their reproductive characters is scant. The spermatozoa of Diopatra neapolitana were ultrastructurally investigated by electron microscopy in order to correlate the mode of reproduction with sperm cells morphology. The mature male gamete has a depressed subspherical nucleus, a cone-like acrosome, and a long flagellum. The acrosome is conical in shape and radially symmetrical, with a base diameter twice the height. Within the acrosome vesicle, the basal region includes a very electron-dense thickened ring composed of paracrystalline substances. The subacrosomal space is filled with a poorly electron-dense material, with straight filaments axially arranged to form a perforatorium. The nucleus contains the complete axial canal, holding the hind perforatorium region. The middle piece consists of five mitochondria with well-distinct membranes and tubulo-vesicular cristae. Two centrioles are located perpendicularly to each other. The proximal one lies in the central fossa and the distal one, slightly eccentric to the sperm axis, anchors to the plasma membrane by nine satellite rays of the pericentriolar complex. The axoneme has a 9+2 arrangement of microtubules. In general, the spermatozoon of D. neapolitana conforms exteriorly to the typical ect-aquasperm; the acrosome complex ultrastructure, however, shows noticeable modifications from the basic form. This finding agrees with the previously observed reproductive pattern (broadcast spawning—free-swimming larvae) of D. neapolitana belonging to Santa Gilla population, and may be helpful to solve the taxonomic problems of the D. neapolitana complex as well.     

Ontogeny of the suspensorial and opercular musculature in the suckermouth armoured catfish <Emphasis Type="Italic">Ancistrus</Emphasis> cf. <Emphasis Type="Italic">triradiatus</Emphasis> (Loricariidae,Siluriformes)

Several morphological features characterizing Loricariidae or suckermouth-armoured catfishes (Siluriformes, Teleostei) are related to their ability to attach onto substrates with their sucker mouth, and to scrape algae and other food items from these substrates. Suspensorial and opercular muscles are among those muscles usually involved in respiration (and feeding). In several loricariids including the genus Ancistrus, the opercular musculature is decoupled from the respiratory mechanisms. Results show that the adductor arcus palatini is relatively large throughout the whole ontogeny, while the levator arcus palatini is minute. It develops in association with the dilatator operculi, which exhibits substantial growth only in the juvenile and adult stages. The levator and adductor operculi are connected during early ontogeny, and anterior fibres of the latter muscle differentiate into the adductor hyomandibulae, a muscle previously thought to be absent in loricariids. Relative muscle sizes and orientations, as well as articular transformations and the transition from cartilaginous to bony skeletal elements, indicate ontogenetic transformations in the skeleto-muscular system, affecting and steering functionalities.     

<Emphasis Type="Italic">Polydora uncinata</Emphasis> (Polychaeta: Spionidae) in Chile: an accidental transportation across the Pacific

A Polydora species was found boring in shells of the abalone Haliotis discus hannai cultivated in land-based tanks in Coquimbo, Chile. Spionid polychaetes of Polydora and related genera have been reported from Chile but no worms similar to those found in abalone have been described. The abalone pest corresponds in morphology to Polydora uncinata Sato-Okoshi, 1998, a shell-boring species which was originally described from Japan and never reported from outside the country. It is suggested that occurrence of the species in Chile resulted from its accidental transportation from Japan. Adult worms were most likely transported to Coquimbo with imported abalone brood stock. Prevalence of abalone infestation by worms in Coquimbo varied substantially among cultivation tanks, reaching values as high as 98.8%. Up to 42 worms were found in one shell. The worms often caused formation of nacreous blisters which covered up to 50% of the inner shell surface. Egg capsules with developing larvae were present in female burrows. Larval development was entirely lecithotrophic, with larvae feeding on numerous nurse eggs, staying inside egg capsules until 16–17-segment stage and hatching shortly before metamorphosis. Polydora uncinata is redescribed based on individuals from Coquimbo to alert zoologists in case of accidental release of worms into Chilean coastal waters. Regardless of how the species was transported to Chile, its release to the natural ecosystem may have negative unforeseen impacts on the native fauna.     

Functional conservation of the human <Emphasis Type="Italic">EXT1</Emphasis> tumor suppressor gene and its <Emphasis Type="Italic">Drosophila</Emphasis> homolog <Emphasis Type="Italic">tout</Emphasis><Emphasis Type="Italic">velu</Emphasis>

Heparan sulfate proteoglycans play a vital role in signaling of various growth factors in both Drosophila and vertebrates. In Drosophila, mutations in the tout velu (ttv) gene, a homolog of the mammalian EXT1 tumor suppressor gene, leads to abrogation of glycosaminoglycan (GAG) biosynthesis. This impairs distribution and signaling activities of various morphogens such as Hedgehog (Hh), Wingless (Wg), and Decapentaplegic (Dpp). Mutations in members of the exostosin (EXT) gene family lead to hereditary multiple exostosis in humans leading to bone outgrowths and tumors. In this study, we provide genetic and biochemical evidence that the human EXT1 (hEXT1) gene is conserved through species and can functionally complement the ttv mutation in Drosophila. The hEXT1 gene was able to rescue a ttv null mutant to adulthood and restore GAG biosynthesis.     

Morphological and physiological development of anterior thoracic stretch receptors in two isopods, <Emphasis Type="Italic">Armadillidium vulgare</Emphasis> and <Emphasis Type="Italic">Ligia exotica</Emphasis>

Abdominal muscle receptor organs (MROs) monitor the position and movement of abdomen in crustaceans. Thoracic segments of decapods are fused and immovable. It is speculated that MROs had retrograded simple shape, N-cells that lost receptor muscles, a receptor cell and accessory nerves. We focused on the effect of segmental movement in respect to thoracic N-cells and MROs in isopods that have movable thoracic segments. Armadillidium vulgare rolled up its body segments. Ligia exotica swam by quick movement of the posterior thoracic segments. Both isopods possessed N-cells and MROs in the thorax. N-cells were a simple structure, but N-cells from the second and third thoracic segments of A. vulgare had a muscle strand. MROs^T3–T4 (from the third and fourth thoracic segments) of A. vulgare had two receptor muscles. MROs^T3–T4 of L. exotica had one long receptor muscle. N-cells of both species and MROs of A. vulgare showed slowly adapting stretch-activated discharges. MROs of L. exotica showed both slowly and rapidly adapting discharges. The stretch-activated responses of N-cells and MROs inhibited each other. N-cells or MROs in the thorax of isopods are not related to the segmental structure. The morphology and physiology of N-cells and MROs are specialized to species–specific behaviors.     

A new species of <Emphasis Type="Italic">Laonice</Emphasis> (Spionidae,Polychaeta, Annelida) from Bellingshausen Sea (West Antarctica)

During the Antarctic summers of 2002–2003 and of 2005–2006, the Spanish BENTART cruises were conducted to the Bellingshausen Sea (Western Antarctica), aiming to study its benthic communities, from depths ranging from 100 to 2,000 m. To achieve it, 30 stations were selected; each one was surveyed in such a way that the infaunal, epifaunal and suprabenthic components of the communities were sufficiently characterized. As a part of the study, some spionid individuals were identified as belonging to a new species of the genus Laonice Malmgren, 1867. The new species belongs to a group within the genus that is characterized by the presence of more than two rows of very numerous capillary chaetae in both noto- and neuropodial fascicles of anterior part of the body. However, it can be readily distinguished from the rest of species within the group by the posterior position in which neuropodial pouches appear (chaetiger 16 or 17) and by the caruncle reaching posteriorly chaetiger 19. In addition, other remarkable features of the new species are the short and triangular occipital tentacle, the rudimentary eyes, the hooded neuropodial hooks first appearing in chaetigers 34–37 and the sabre neurochaetae first occurring in chaetigers 20–27.     

A PCR survey of <Emphasis Type="Italic">Hox</Emphasis> genes in the myzostomid <Emphasis Type="Italic">Myzostoma cirriferum</Emphasis>

Using degenerate primers, we were able to identify seven Hox genes for the myzostomid Myzostoma cirriferum. The recovered fragments belong to anterior class (Mci_lab, Mci_pb), central class (Mci_Dfd, Mci_Lox5, Mci_Antp, Mci_Lox4), and posterior class (Mci_Post2) paralog groups. Orthology assignment was verified by phylogenetic analyses and presence of diagnostic regions in the homeodomain as well as flanking regions. The presence of Lox5, Lox4, and Post2 supports the inclusion of Myzostomida within Lophotrochozoa. We found signature residues within flanking regions of Lox5, which are also found in annelids, but not in Platyhelminthes. As such the available Hox genes data of myzostomids support an annelid relationship. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

<Emphasis Type="Italic">Drosophila</Emphasis><Emphasis Type="Italic">P</Emphasis> transposons of the urochordata <Emphasis Type="Italic">Ciona intestinalis</Emphasis>

P transposons belong to the eukaryotic DNA transposons, which are transposed by a cut and paste mechanism using a P-element-coded transposase. They have been detected in Drosophila, and reside as single copies and stable homologous sequences in many vertebrate species. We present the P elements Pcin1, Pcin2 and Pcin3 from Ciona intestinalis, a species of the most primitive chordates, and compare them with those from Ciona savignyi. They showed typical DNA transposon structures, namely terminal inverted repeats and target site duplications. The coding region of Pcin1 consisted of 13 small exons that could be translated into a P-transposon-homologous protein. C. intestinalis and C. savignyi displayed nearly the same phenotype. However, their P elements were highly divergent and the assumed P transposase from C. intestinalis was more closely related to the transposase from Drosophila melanogaster than to the transposase of C. savignyi. The present study showed that P elements with typical features of transposable DNA elements may be found already at the base of the chordate lineage. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Polymorphism of canonical and noncanonical <Emphasis Type="Italic">gypsy</Emphasis> sequences in different species of <Emphasis Type="Italic">Drosophila </Emphasis><Emphasis Type="Italic">melanogaster</Emphasis> subgroup: possible evolutionary relations

Mobile genetic elements constitute a substantial part of eukaryotic genome and play an important role in its organization and functioning. Co-evolution of retrotransposons and their hosts resulted in the establishment of control systems employing mechanisms of RNA interference that seem to be impossible to evade. However, “active” copies of endogenous retrovirus gypsy escape cellular control in some cases, while its evolutionary elder “inactive” variants do not. To clarify the evolutionary relationship between “active” and “inactive” gypsy we combined two approaches: the analysis of gypsy sequences, isolated from G32 Drosophila melanogaster strain and from different Drosophila species of the melanogaster subgroup, as well as the study of databases, available on the Internet. No signs of “intermediate” (between “active” and “inactive”) gypsy form were found in GenBank, and four full-size G32 gypsy copies demonstrated a convergence that presumably involves gene conversion. No “active” gypsy were revealed among PCR generated gypsy ORF3 sequences from the various Drosophila species indicating that “active” gypsy appeared in some population of D. melanogaster and then started to spread out. Analysis of sequences flanking gypsy variants in G32 revealed their predominantly heterochromatic location. Discrepancy between the structure of actual gypsy sites in G32 and corresponding sequences in database might indicate significant inter-strain heterochromatin diversity. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Molecular phylogeny of horsetails (<Emphasis Type="Italic">Equisetum</Emphasis>) including chloroplast <Emphasis Type="Italic">atpB</Emphasis> sequences

Equisetum is a genus of 15 extant species that are the sole surviving representatives of the class Sphenopsida. The generally accepted taxonomy of Equisetum recognizes two subgenera: Equisetum and Hippochaete. Two recent phylogenetical studies have independently questioned the monophyly of subgenus Equisetum. Here, I use original (atpB) and published (rbcL, trnL-trnF, rps4) sequence data to investigate the phylogeny of the genus. Analyses of atpB sequences give an unusual topology, with E. bogotense branching within Hippochaete. A Bayesian analysis based on all available sequences yields a tree with increased resolution, favoring the sister relationships of E. bogotense with subgenus Hippochaete.     

The musculature of horsehair worm larvae (<Emphasis Type="Italic">Gordius aquaticus</Emphasis>,<Emphasis Type="Italic"> Paragordius varius</Emphasis>, Nematomorpha): F-actin staining and reconstruction by cLSM and TEM

The musculature of larvae of Gordius aquaticus was investigated by laser-scanning microscopy and compared to transmission electron microscopic data for the larva of Paragordius varius. In the anterior portion of the body, the preseptum, four different muscle groups can be distinguished: (1) 12 anterior parietal muscles in the body wall, (2) six oblique muscles that function as retractors of the introvert, (3) six proboscideal muscles, which function as retractors for the proboscis, and (4) six muscles associated with spines of the outermost of the three rings of spines. The posterior portion of the body, the postseptum, possesses four pairs of longitudinal muscle strands in G. aquaticus, the postseptal parietal muscles, that are located dorsolaterally and ventrolaterally. These are not clearly visible in P. varius, where instead three pairs of parietal muscles are present. Additional small muscles are associated with the terminal spines and with the duct running from the pseudointestine to the body wall. All fibers show a cross-striated pattern although this striation is less obvious at the ends of the fibers.     

<Emphasis Type="Italic">smyd1</Emphasis> and <Emphasis Type="Italic">smyd2</Emphasis> are expressed in muscle tissue in <Emphasis Type="Italic">Xenopus laevis</Emphasis>

Epigenetic modifications of histone play important roles for regulation of cell activity, such as cell division, cell death, and cell differentiation. A SET domain consisting of about 130 amino acids has lysine methyltransferase activity in the presence of the cosubstrate S-adenosyl-methionine. More than 60 SET domain-containing proteins have been predicted in various organisms. One of them, the SMYD family genes which contain a SET domain and a zinc-finger MYND domain are reported to regulate cell cycle and muscle formation. Here we examined the expression and function of smyd1 and 2 in Xenopus. smyd1 and 2 were expressed in various muscle tissues. While smyd1 expression was observed mainly in cardiac muscle and skeletal muscle, smyd2 expression was done abundantly in skeletal muscle and face region. Moreover, by loss-of-function experiments using antisense morpholino oligonucleotides, it was suggested that smyd1 and 2 related to muscle cells differentiation.     

New combinations and typifications in <Emphasis Type="Italic">Bistorta</Emphasis>, <Emphasis Type="Italic">Persicaria</Emphasis>, <Emphasis Type="Italic">Polygonum,</Emphasis> and <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae)

New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.     

The cellulose synthase (<Emphasis Type="Italic">CESA</Emphasis>) gene superfamily of the moss <Emphasis Type="Italic">Physcomitrella patens</Emphasis>

The CESA gene superfamily of Arabidopsis and other seed plants comprises the CESA family, which encodes the catalytic subunits of cellulose synthase, and eight families of CESA-like (CSL) genes whose functions are largely unknown. The CSL genes have been proposed to encode processive β-glycosyl transferases that synthesize noncellulosic cell wall polysaccharides. BLAST searches of EST and shotgun genomic sequences from the moss Physcomitrella patens (Hedw.) B.S.G. were used to identify genes with high similarity to vascular plant CESAs, CSLAs, CSLCs, and CSLDs. However, searches using Arabidopsis CSLBs, CSLEs, and CSLGs or rice CSLFs or CSLHs as queries identified no additional CESA superfamily members in P. patens, indicating that this moss lacks representatives of these families. Intron insertion sites are highly conserved between Arabidopsis and P. patens in all four shared gene families. However, phylogenetic analysis strongly supports independent diversification of the shared families in mosses and vascular plants. The lack of orthologs of vascular plant CESAs in the P. patens genome indicates that the divergence of mosses and vascular plants predated divergence and specialization of CESAs for primary and secondary cell wall syntheses and for distinct roles within the rosette terminal complexes. In contrast to Arabidopsis, the CSLD family is highly represented among P. patens ESTs. This is consistent with the proposed function of CSLDs in tip growth and the central role of tip growth in the development of the moss protonema. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. Accession numbers: DQ417756, DQ417757, DQ898284–6, DQ898147–54, DQ902545–51.     

Sonication assisted <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation enhances the transformation efficiency in flax (<Emphasis Type="Italic">Linum usitatissimum</Emphasis> L<Emphasis Type="Italic">.</Emphasis>)

A sonication-assisted, Agrobacterium-mediated, co-cultivation technique was used in an attempt to increase the transformation efficiency of flax. Hypocotyls and cotyledons excised from about 10-day-old flax seedlings grown in vitro were placed into a 10 mM MgSO₄ solution, and inoculated with an A. tumefaciens vector bearing the mgfp5-ER gene driven by the CaMV 35S promoter. The explants were subjected to pulses of ultrasound delivered by a sonicator apparatus (35 kHz) for 0–150 s and co-cultivated for 2 h at 27°C. The dried hypocotyls and cotyledons were grown on a selective MS medium to promote shoot regeneration. An electron microscopic study showed that the sonication treatment resulted in thousands of microwounds on and below the surface of the explants. A stereo microscope Leica MZ 12 equipped with a GFP adaptor was used to assess the infection and transformation of plant tissues in real time. After only 48 h and for at least 30 days after bacteria elimination, signs of transgene expression could be seen as a bright fluorescence. Our results show that treatment with ultrasound facilitates an enhanced uptake of plasmid DNA into the cells of flax hypocotyls and cotyledons and that its efficiency depends on the duration of the treatment and the frequency used. SAAT could be a promising tool for enhancing transformation efficiency in flax.     

Floral development and systematic position of <Emphasis Type="Italic">Arillastrum</Emphasis>, <Emphasis Type="Italic">Allosyncarpia</Emphasis>, <Emphasis Type="Italic">Stockwellia</Emphasis> and <Emphasis Type="Italic">Eucalyptopsis</Emphasis> (Myrtaceae)

We have investigated the floral ontogeny of Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis (of the eucalypt group, Myrtaceae) using scanning electron microscopy and light microscopy. Several critical characters for establishing relationships between these genera and to the eucalypts have been determined. The absence of compound petaline primordia in Arillastrum, Allosyncarpia, Stockwellia and Eucalyptopsis excludes these taxa from the eucalypt clade. Post-anthesis circumscissile abscission of the hypanthium above the ovary in Stockwellia, Eucalyptopsis and Allosyncarpia is evidence that these three taxa form a monophyletic group; undifferentiated perianth parts and elongated fusiform buds are characters that unite Stockwellia and Eucalyptopsis as sister taxa. No floral characters clearly associate Arillastrum with either the eucalypt clade or the clade of Stockwellia, Eucalyptopsis and Allosyncarpia.We gratefully acknowledge Clyde Dunlop and Bob Harwood (Northern Territory Herbarium) for collecting specimens of Allosyncarpia, and Bruce Gray (Atherton) for collecting specimens of Stockwellia. The Australian National Herbarium (CANB) kindly lent herbarium specimens of Eucalyptopsis for examination. This research was supported by a University of Melbourne Research Development Grant to Andrew Drinnan.