Plumatella nitens, a new species of freshwater bryozoan from North America (Ectoprocta: Phylactolaemata), previously misidentified

Plumatella nitens is a newly recognized species of phylactolaemate bryozoan in North America. It has previously been combined with either P. repens or P. fungosa, from which it differs primarily by the floatoblast. In P. nitens the ventral floatoblast annulus is uniformly narrow with no significant widening at the poles. The dorsal floatoblast fenestra is conspicuously larger than in either P. repens or P. fungosa. Reticulated ridges on the dorsal fenestra are weak along the margins, becoming unusually prominent in the center. The sessoblast is densely covered with uneven papillae. Spotty sampling so far shows a distribution only in the northern half of North America, including Massachusetts, Michigan, Minnesota, Wisconsin, Ontario, and the northern regions of Illinois, Indiana, and Ohio.     

Taxonomic and Molecular Identification of Bakernema,Criconema, Hemicriconemoides,Ogma and Xenocriconemella Species (Nematoda: Criconematidae)

Populations of Bakernema inaequale, C. petasum, C. sphagni, C. mutabile, Ogma octangulare, Xenocriconemella macrodora and Hemicriconemoides chitwoodi were identified and re-described from different geographical areas in the continental United States and molecularly characterized. Two new species of spine nematodes Criconema arkaense n. sp. from Washington County and Lee County, Arkansas and Criconema warrenense n. sp from Warren, Bradley County, Arkansas are also described and named. Criconema arkaense is characterize by having a conspicuous lip region offset from the body with two annuli, short rounded tail with a thin cuticular sheath and subterminal anus. Criconema warrenense n. sp. has two lip region annuli about the same width, first annulus directed posteriorly, separated by a narrow neck annulus and a short conoid tail, unilobed non-folded annulus. The molecular characterization of Criconema arkaense and Criconema warrenense using ITS1 rDNA gene sequence and the molecular phylogenetic relationships of these new species along with the known spines nematodes are provided.     

A new species of Astomiopsis (Ditrichaceae) from Mexico

Astomiopsis saintpierrei Thér. ex Buck is described as new from Nevado de Toluca in Mexico. It is characterized by oblong-lanceolate leaves with recurved margins and a percurrent costa. The capsules are immersed, have a well-developed, deciduous annulus, and are covered with a large, cucullate calyptra. A key to the five known species ofAstomiopsis is given.     

A new species of Amanita section Lepidella from South China

Amanita macrocarpa from Guangdong Province of China is described. The new species is a large, brownish orange to light brown mushroom, characterized by numerous pyramidal warts on the pileus, yellowish lamellae, a large annulus at the middle of the stipe, and amyloid ellipsoidal basidiospores. Phylogenetic analyses of the new species and related taxa based on the large subunit of nuclear ribosomal DNA (LSU) and the internal transcribed spacer (ITS) sequences are provided. Morphological and molecular data show that A. macrocarpa is a member of Amanita, section Lepidella, and clearly different from any known taxon of the section.     

Phylogenetic relationships of freshwater bryozoans (Ectoprocta, Phylactolaemata) inferred from mitochondrial ribosomal DNA sequences

Most species of freshwater bryozoans (Ectoprocta: Phylactolaemata) have few morphological distinctions, and within phylactolaemates, the morphology of the statoblast has been used to determine evolutionary relationships. Here, two controversial phylogenies have been proposed for phylactolaemates with regard to the relationship of Lophopodidae to other families. Two plumatellid genera, Gelatinella and Hyalinella , are candidates for the ancestral type of lophopodids. In addition, the coexistence of spines on the surfaces of the statoblast has led to the suggestion that lophopodids are closely related to the family Cristatellidae. In this study, we analysed mitochondrial DNA sequences of the 12S and 16S rDNA genes of 10 phylactolaemate species. Our results suggest that plumatellids may not be a direct ancestral group of lophopodids and that cristatellids are not a sister group of lophopodids. Fredericella , which was previously thought to be an ancestral group, was revealed to be derived. In addition, our results suggest that Stephanella is the most basal phylactolaemate. Mapping morphological characteristics onto the sequence-based phylogenetic tree revealed convergent evolution of statoblast characters.     

Age validation of juvenile Notothenia rossii at Potter Cove, South Shetland Islands, using mark-recapture data

Among all validation methods of age determination in fish, release of known age and marked specimens gives the most reliable information. We carried out a tag-recapture experiment on Notothenia rossii at Potter Cove, to validate, for first time for this species using this method, the principle of annual deposition of an annulus in scales and otoliths. Of 132 juvenile specimens (TL = 22.1–38.1 cm) tagged and released in successive years from 2004 to 2010, 7 were recaptured at the same site after periods of 1–13 months. In scales of five specimens recovered after 10–13 months, one extra annulus was laid down, exhibiting an additional winter zone of closely spaced sclerites. Consistently, the same analysis in two individuals marked and recaptured during the same summer, after 1–3 months at liberty, did not show the deposition of an additional annulus. All the fish tagged or recaptured during the experiment period (December to March) showed in their scales an edge zone of widely spaced sclerites, in agreement with the known pattern of growth in summer. Likewise, an analysis in selected specimens showed good consistency between the numbers of sclerites deposited in scales and the time of fish release. The comparative analysis between scales taken at recapture and otoliths of the same individual allowed a simultaneous counting of the annuli with complete correspondence. The growth in length of fish ranged from 0.5 to 6.1 cm, depending on the time of release.     

Descriptions of Four New Species of Criconematoidea (Tylenchina: Nemata) from Southern Chile

Four new species of Criconematoidea are described from Hoste Island, Chile. Criconema certesi n. sp. is distinguished by the fine, spine-like, cuticular extensions on body annuli; projection of annuli into rows of scales on posterior part of body; single, smooth, labial annulus set off by short collar from second (first body) annulus which is about same diameter as first (labial) annulus. Male with prominent caudal alae, slender curved spicules, and four incisures in lateral field. Ogma terrestris n. sp. is distinguished by small scales with rounded tips bearing minute, short bristles; scales number 21 at mid-body; and first (labial) annulus rounded, not retrorse, not set off from succeeding annuli, narrower in diameter from second (first body) annulus. Hemicycliophora macrodorata n. sp. is distinguished by its large size (L = 1.52 [1.28-1.72] mm); large stylet (146 [127-161] μm); annuli = 297 (280-315); tail slightly spicate, lateral field with or without interruptions of incisures, occasional anastomoses; and males with U-shaped spicules. Paratylenchus fueguensis n. sp. is distinguished by its prominent stylet with large, rounded knobs (4-5 μm across); cephalic region rounded not at all set off; lateral field with four incisures; lateral vulvar membranes present; and male tail short, strongly curved (almost 180°) ventrad.     

Global diversity of bryozoans (Bryozoa or Ectoprocta) in freshwater

The present study considers 88 bryozoan species occurring in freshwater: 69 phylactolaemate and 19 gymnolaemate species. Roughly 49% of these species are confined to one zoogeographical region. The cosmopolitan status of species like Fredericella sultana, Plumatella repens or P. emarginata has to be reconsidered. Among the Phylactolaemata, which are phylogenetically older than the Gymnolaemata, the gelatinous species (Lophopodidae, Pectinatellidae, Cristatellidae) are more primitive than the branching tubular species (Plumatellidae, Fredericellidae). Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Validation of first annulus formation in red snapper otoliths with the use of an alizarin complexone fluorescent marker

The red snapper (Lutjanus campechanus) is among the most studied reef fish species in the Gulf of Mexico. Several studies have used counts of annuli in sectioned sagittal otoliths to age red snapper. However, interpretation of the putative first annulus has been a major source of debate among otolith readers throughout the Gulf of Mexico. Our objective was to use the chemical marker alizarin complexone to validate the periodicity of first opaque annulus formation in red snapper otolith sections. Juvenile red snapper were immersed in 100 mg alizarin complexone per L seawater solution in November 2005 and then reared in 6000 l circular tanks until July 2006. Otoliths were then removed from the fish and thin sectioned. All experimental otolith sections displayed a distinct fluorescent mark ranging from 0.62 to 0.96 mm from the core when viewed under the microscope with a rhodamine filter. The diffuse opaque annulus was located distally to the alizarin mark in all specimens (ranging from 0.88 to 1.51 mm). The distal position of the presumptive first annulus relative to the alizarin mark in all specimens indicates that this diffuse opaque annulus in red snapper sectioned otoliths forms during the first winter after hatching. Translucent marginal edges of all otolith sections indicate that first opaque annulus formation is completed by mid-July.     

Systematics of the genus Ceratopteris Brongn. (Parkeriaceae) II. Taxonomy

A revision of the genusCeratopteris is presented based on comparative morphology and geographical distribution. Four species are recognized:C. thalictroides, C. cornuta, C. pteridoides, andC. richardii. Characteristics of taxonomic importance include frond length, shape, and dissection; stipe width; insertion of basal pinnae; bud development; habit; annulus cell number; spore number per sporangium; spore size; and spore surface features. Evolution within species and putative hybridization between species are discussed.     

Cysteine proteinase inhibitors of the canine intervertebral disc

Several species of cysteine proteinase inhibitors have been demonstrated in the greyhound intervertebral disk which were resolved four species (M_r 15 8000, 16 600, 17 200 and 17 800) by gelatin-SDS-polyacrylamide gel electrophoresis. Reductive alkylation did not affect their inhibitory capability not their electrophoretic migration on gelatin-SDS-polyacrylamide gel electrophoresis. The cysteine proteinase inhibitors from the nucleus pulposus and annulus fibrosus were identical as assessed by the aforementioned criteria, although the level in the nucleus was found to be higher than that in the annulus. Ion-exchange chromatography demonstrated distinct acidic and basic forms of the disc cysteine proteinase inhibitor. The latter species was the most abundant and its M_r was determined to be 16 900 by gelatin-SDS-polyacrylamide gel electrophoresis. Both forms were shown to be strongly inhibitory against the cysteine proteinases. papain and ficin, but were less strongly inhibitory against cathepsin B (EC 3.4.22.1). Presumably these disc cysteine proteinase finhibitors play a regulatory role in the metabolism of proteoglycans and collagen by endogenous cysteine proteinases.     

Brain-derived neurotrophic factor and its receptor in the human and the sand rat intervertebral disc

Introduction

Brain-derived neurotrophic factor (BDNF) was first identified in the intervertebral disc (IVD) when its molecular upregulation was observed in sections of nucleus pulposus cultured under conditions of increased osmolarity. BDNF is now known to be involved in a number of biologic functions, including regulation of differentiation/survival of sensory neurons, regulation of nociceptive function and central pain modulation, and modulation of inflammatory pain hypersensitivity. In addition, more recent investigations show that BDNF can induce the recruitment of endothelial cells and the formation of vascular structures. The objectives of the present study were to use immunocytochemistry to determine the distribution of BDNF and its receptor (BDNF-tropomyosine receptor kinase B) in the human IVD, and to test for gene expression of BDNF and its receptor in cultured human annulus fibrosus cells.

Methods

We studied immunohistochemical localization of BDNF and its receptor in the human annulus, quantified the percentage of outer annulus and inner annulus cells and nucleus cells positive for BDNF immunolocalization, and studied the gene expression of BDNF and its receptor using microarray analysis.

Results

The percentage (mean ± standard error of the mean) of cells positive for BDNF localization was significantly greater in the outer annulus (32.3 ± 2.7%, n = 22) compared with either the inner annulus (8.1 ± 1.5%, n = 6) or the nucleus (10.4 ± 2.8%, n = 3) (P < 0.0001). BDNF-receptor immunolocalization showed a pattern similar to that of BDNF, but was not quantitatively assessed. BDNF gene expression levels from cultured annulus cells showed a significant positive correlation with increasing levels of IVD degeneration (P = 0.011).

Conclusion

These findings provide data on the presence of BDNF and its receptor in the human IVD at the translational level, and on the expression of BDNF and its receptor by cultured human annulus cells. Our findings point to the need for further studies to define the role of BDNF in the human IVD and to investigate regulatory events within the disc that control the expression of BDNF and its receptor.     

Analysis of the Torus Surrounding Planar Lipid Bilayer Membranes

The characteristics and behavior of the torus (annulus) surrounding planar lipid bilayer membranes formed across a cylindrical aperture are analyzed using equations for the shape and volume of the annulus derived by the methods of variational calculus. The analysis leads to the following results: (a) Design criteria for the aperture can be established. (b) The transition region between thin film and thick annulus can be defined quantitatively and its effect on the measurement of specific capacitance determined. (c) At fixed annulus volume the diameter of the thin membrane is a function of the thin film-annulus contact angle. This suggests a new method for examining changes in free energy of the thin film, and explains why the area of thin film increases reversibly when potentials are present across the film. (d) In the absence of buoyant forces, the equations for the shape and volume of the annulus consist of incomplete elliptic integrals of the first and second kinds; however, the shape of the annulus in the transition region can be described with good accuracy by an approximate equation of greater simplicity.     

Particle capture in ciliary filter‐feeding gymnolaemate and phylactolaemate bryozoans – a comparative study

Riisgård, H.U., Okamura, B. and Funch, P. 2009. Particle capture in ciliary filter‐feeding gymnolaemate and phylactolaemate bryozoans – a comparative study. —Acta Zoologica (Stockholm) 91 : 416–425. We studied particle capture using video‐microscopy in two gymnolaemates, the marine cheilostome Electra pilosa and the freshwater ctenostome Paludicella articulata, and three phylactolaemates, Fredericella sultana with a circular funnel‐shaped lophophore, and Cristatella mucedo and Lophophus crystallinus, both with a horseshoe‐shaped lophophore. The video‐microscope observations along with studies of lophophore morphology and ultrastructure indicated that phylactolaemate and gymnolaemate bryozoans with a diversity of lophophore shapes rely on the same basic structures and mechanisms for particle capture. Our study also demonstrates that essential features of the particle capture process resemble one another in bryozoans, brachiopods and phoronids.     

Two new lineages of aquatic ascomycetes: <Emphasis Type="Italic">Atractospora</Emphasis> gen. nov. and <Emphasis Type="Italic">Rubellisphaeria</Emphasis> gen. et sp. nov., and a sexual morph of <Emphasis Type="Italic">Myrmecridium montsegurinum</Emphasis> sp. nov.

Two new genera, Atractospora and Rubellisphaeria, are described for perithecial ascomycetes occurring on decaying wood submerged in freshwater habitats. Their relationships with other morphologically similar fungi were investigated utilising four nuclear ribosomal and protein-coding loci. They are nested together with members of five orders and families and numerous genera incertae sedis in the Sordariomycetidae in a clade supported by Maximum Likelihood and Bayesian inference methods. Their closest relative is Lentomitella. Atractospora includes species characterised by dark, immersed to semi-immersed beaked ascomata lying horizontally to the host, stipitate asci with a pronounced non-amyloid apical annulus and hyaline, fusiform, septate, thick-walled ascospores with smooth or ornamented wall. Three novel species are introduced (A. decumbens, A. reticulata and A. verruculosa). A new combination for Aquaticola ellipsoidea is proposed in Atractospora based on molecular data and morphological characters. Rubellisphaeria, with a new species R. abscondita, is distinct by subhyaline to reddish brown, immersed ascomata with a lateral neck, short-stipitate asci and ellipsoidal smooth ascospores with a delayed formation of a middle septum. The sexual morph of the dematiaceous hyphomycete genus Myrmecridium was encountered for the first time on decaying wood submerged in a stream. It is nested in a strongly supported monophyletic clade of the Myrmecridiales. The novel species M. montsegurinum is described; it possesses papillate ascomata immersed beneath a clypeus with subhyaline to weakly pigmented ascomatal wall, long-stipitate asci with a non-amyloid apical annulus and three-septate, hyaline, ellipsoidal, delicately verruculose ascospores. A morphology-based key is provided to facilitate identification of species of Atractospora.     

Organogenesis in the budding process of the freshwater bryozoan Cristatella mucedo Cuvier, 1798 (bryozoa,phylactolaemata)

The phylogenetic position of bryozoans has been disputed for decades, and molecular phylogenetic analyzes have not unequivocally clarified their position within the Bilateria. As probably the most basal bryozoans, Phylactolaemata is the most promising taxon for large‐scale phylogenetic comparisons. These comparisons require extending the morphological and developmental data by investigating different phylactolaemate species to identify basal characters and resolve in‐group phylogeny. Accordingly, we analyzed the bud development and the organogenesis of the freshwater bryozoan Cristatella mucedo, with special focus on the formation of the digestive tract and differentiation of the coelomic compartments. Most parts of the digestive tract are formed as an outpocketing at the future anal side growing towards the mouth area. The ganglion is formed by an invagination between the anlagen of the mouth and anus. The lophophoral arms develop as paired lateral protrusions into the lumen of the bud and are temporarily connected by a median, thin bridge. All coelomic compartments are confluent during their development and also in the adult. The epistome coelom develops by fusion of two peritoneal infolds between the gut loop and overgrows the ganglion medially. The coelomic ring canal on the oral side develops by two lateral ingrowths and supplies the oral tentacles. On the forked canal, supplying the innermost row of tentacles above the epistome, a bladder‐shaped swelling, probably with excretory function, is present in some adults. It remains difficult to draw comparisons to other phyla because only few studies have dealt with budding of potentially related taxa in more detail. Nonetheless, our results show that comparative organogenesis can contribute to phylactolaemate systematics and, when more data are available, possibly to that of other bryozoan classes and bilaterian phyla. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc.     

Genetic fate mapping demonstrates contribution of epicardium-derived cells to the annulus fibrosis of the mammalian heart

The annulus fibrosis electrically insulates the atria and ventricles, allowing the timed sequential beating of these structures that is necessary for efficient heart function. Abnormal development of the annulus fibrosis leads to persistence of accessory electrical pathways from atria to ventricles, providing the anatomical substrate for re-entrant cardiac arrhythmias such as Wolff-Parkinson-White syndrome. To better understand the development of the annulus fibrosis and the etiology of these cardiac arrhythmias, we used Cre-LoxP technology to assess the contribution of epicardium derived cells (EPDCs) to the annulus fibrosis. We found that EPDCs migrated into the region of the forming annulus fibrosis, marked by the protein periostin. These EPDCs also stained positive for procollagen I, suggesting that the EPDCs themselves synthesize proteins of the annulus fibrosis. To further test the hypothesis that EPDCs contribute to cells that synthesize the annulus fibrosis, we purified genetically marked EPDCs from the atrioventricular region and measured gene expression by quantitative PCR. These EPDCs were highly enriched for mRNAs encoding periostin, procollagen I, fibronectin I, vimentin, discoidin domain receptor 2, and tenascin C, markers of fibroblasts and components of the annulus fibrosis. In addition, these EPDCs were highly enriched for Snail, Smad1, Slug, and Twist1, markers for epithelial-to-mesenchymal transition (EMT), and a metalloprotease, Mmp2, that contributes to cellular migration. Our work provides for the first time definitive evidence that epicardium contributes to formation of the mammalian annulus fibrosis through EMT. Abnormalities of this differentiation process may underlie development of some forms of re-entrant atrioventricular tachycardia.