Processing by proprotein convertases is required for glypican-3 modulation of cell survival, Wnt signaling, and gastrulation movements

Glypican (GPC)-3 inhibits cell proliferation and regulates cell survival during development. This action is demonstrated by GPC3 loss-of-function mutations in humans and mice. Here, we show that the GPC3 core protein is processed by a furinlike convertase. This processing is essential for GPC3 modulating Wnt signaling and cell survival in vitro and for supporting embryonic cell movements in zebrafish. The processed GPC3 core protein is necessary and sufficient for the cell-specific induction of apoptosis, but in vitro effects on canonical and noncanonical Wnt signaling additionally require substitution of the core protein with heparan sulfate. Wnt 5A physically associates only with processed GPC3, and only a form of GPC3 that can be processed by a convertase is able to rescue epiboly and convergence/extension movements in GPC3 morphant embryos. Our data imply that the Simpson-Golabi-Behmel syndrome may in part result from a loss of GPC3 controls on Wnt signaling, and suggest that this function requires the cooperation of both the protein and the heparan sulfate moieties of the proteoglycan.     

A new class of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in plant parasitic cyst nematodes

By performing cDNA AFLP on pre- and early parasitic juveniles, we identified genes encoding a novel type of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in the cyst nematode Heterodera schachtii. The proteins consist of three domains, a signal peptide for secretion, a mono-ubiquitin domain, and a short C-terminal positively charged domain. A gfp-fusion of this protein is targeted to the nucleolus in tobacco BY-2 cells. We hypothesize that the C-terminal peptide might have a regulatory function during syncytium formation in plant roots.     

Three species of Tobrilidae (Nematoda: Enoplida) from Li River at Guiling, China

Eutobrilus annetteae Joubert & Heyns, 1979 with its male reported for the first time, Semitobrilus pellucidus (Bastian, 1865) Tsalolichin, 1983, and Epitobrilus allophysis(Steiner, 1919) Tsalolichin, 1996 are described from the Li River at Guiling, China. The male of Eutobrilus annetteae is characterized by lots of crystalloids inside body, almost straight spicules about one anal body diameter long and seven equally sized supplements. Semitobrilus pellucidus from Guiling shows large variation in body width, position of amphids, form of buccal cavity, distance between denticles, direction of vagina, arrangement of oocytes, and shape of eggs. It is different from other populations in its shorter cephalic setae, less than 60% of head width, in its shorter tail and smaller c value. In males, there are 6–9 supplements, reduced and irregulary spaced. Epitobrilus allophysisis characterized by its labial setae longer than 50% of head width, small, posteriorly located ovoid amphid, single egg occupying whole space of uterus and blunt tail tip.     

A new species of Eumonhystera and three species of Monhystera (Monhysteridae: Nematoda) from Li River,China

A new Eumonhystera species, E. huruii n. sp., together with Monhystera nubiae Eyualem & Coomans, 1996, Monhystera somereni Allgén, 1952, and Monhystera wangi Wu & Hoeppli, 1932 are described from Li river at Guiling, China. Eumonhystera huruii n. sp. is closest to E. barbata Andrássy, 1981, but differs in having shorter anterior setae, much longer reproductive system, shorter and less dorsally bent tail and differently shaped spinneret. M. nubiae and M. wangi are reported here for the first time outside their type locality, whereas M. somereni is reported from China for the first time.     

Two New Species of Prismatolaimus de Man, 1880 (Nemata: Prismatolaimidae) in Southern Chile

Two new species of Prismatolaimus are described from Orange Bay, Hoste Island, Chile. Prismatolaimus novoporus sp. n. is distinguished by its females being 1.08-1.28 mm long and monovarial with a long postvulvar sac, and having a long tail (c'' = 21.5-32.2); males have 11-20 supplements confined to the posterior part of the body. Prismatolaimus chilensis sp. n. is distinguished by its amphidelphic reproductive system, short tail (c'' = 9.5), V = 63.4; males have 23 supplements reaching up to the neck region. A well-developed dorsal body pore behind the cardia connected with an apparently glandular organ is reported in P. novoporus sp. n. Function of the organ is unknown, and it is not a general feature in the genus. The generic diagnosis of Prismatolaimus is emended and keys to species, both females and males, are presented. The systematic position of Prismatolaimus is discussed, and it is judged to be the only genus of Prismatolaimidae. Also, it is concluded that Prismatolaimidae and Bastianidae represent two sister taxa in Araeolaimida or Leptolaimina.     

Freshwater nematodes of the Galápagos

Freshwater nematodes of the Galápagos archipelago were studied from four samples collected in 1988. Eighteen species, two of which are new to science, belonging to five orders, Enoplida, Dorylaimida, Mononchida, Monhysterida and Chromadorida, are described. Alaimus wittmeri n.sp. is characterised by having a smooth cuticle, a more posteriorly enlarged pharynx, a posteriorly situated amphidial fusus, obscure but anteriorly situated excretory pore, a mono-opisthodelphic ovary, and by the absence of sexual dimorphism in the lip region, the absence of pre-vulval uterine sac, the presence of males that have few (4–7) and weak ventromedian supplements and absence of mucro on tail tip. Monhystera floreanae n. sp. is distinguished by its females having a small body (L = 492–634 µm) with a narrow lip region, narrow posteriorly located amphidial openings, a small value for the c'-ratio (c' = 6.0–7.5), weak vaginal sphincter, by the absence of post-vaginal gland cells, absence of males and absence of crystalloid bodies. The difficulty in the use of crystalloid bodies as diagnostic character in the genus Monhystera is discussed. Two forms, a big form and a small form, which are similar except in measurements are reported for Achromadora micoletzkyi. SEM photos of ruptured cuticle of A. micoletzkyi and A. semiarmata show unique intra-cuticular structures. Comparison of these structures in the two species is made. Papilliform instead of setiform outer labial sensilla are also observed in A. micoletzkyi. The presence of the male and fine crystalloid bodies in Achromadora semiarmata, dorsal body pore in Prismatolaimus dolichurus and Prismatolaimus kenyensis, forty longitudinal cuticular ridges around the mid-body of Stomachoglossa pachyderma, crystalloid bodies in Ironus dentifurcatus are reported here for the first time. SEM photos of twelve species: Monhystera floreanae n. sp., Monhystera somereni, Alaimus wittmeri n. sp., Monhystrella hastata, Paramphidelus dolichurus, Eutobrilus annetteae, Ironus dentifurcatus, Chronogaster cameroonensis, Rhabdolaimus terrestris, Stomachoglossa pachyderma, Achromadora micoletzkyi and Achromadora semiarmata, are also presented.The richest nematode fauna was found in El Junco (San Cristobal), the only permanent freshwater lake on the archipelago. The nine species recorded from the lake are probably only a fraction of the total nematode fauna. The very recent man made reservoir La Toma has a relatively high diversity, due to its vicinity to El Junco. It is argued that the freshwater nematodes from San Cristobal probably arrived there through passive transport by birds.The freshwater bodies encountered on Floreana are very different from those on San Cristobal and so is their nematode fauna. Part of the species found on these islands may have been transported by land birds, others may have invaded the freshwater from terrestrial habitats.Apart from the two new species, the other ones have a wide to very wide distribution (cosmopolitan, southern hemisphere, ...), so that endemism of freshwater nematodes is very low, if it exists at all. This is due to easy dispersal capacities of nematodes on the one hand and the recent colonization (not more than 10 000, max. 40 000 years) on the other hand.     

Oncholaimus sahariensis sp.n. (Nematoda) from the Algerian Sahara

Oncholaimus sahariensis sp.n. is described from an oasis in the Algerian Sahara. It differs from O. aquaedulcis Schneider, 1937 and O. deconincki Heyns & Coomans, 1977, the only other freshwater species in the genus, in the more posteriorly situated vulva, the spicules which are longer than in O. deconincki but shorter than in O. aquaedulcis, and various other characteristics. The new species is unusual in that the whole female reproductive system as well as the demanian system are located on the left side of the intestine, whereas the reproductive system is normally to the right in Oncholaimoidea. Problems concerning the validity and differentiation of Oncholaimium Cobb, 1930 are discussed, at the same time explaining why the new species is placed in Oncholaimus rather than in Oncholaimium.     

Nematode communities of Lake Tana and other inland water bodies of Ethiopia

Free-living nematodes from littoral benthic sediments of four lakes, two rivers and a hot spring in Ethiopia are studied. Populations of nematodes encountered are identified to the species level. The general nematode (generic and species) composition of the lakes, rivers and hot spring are appraised by giving special emphasis to the nematodes from L. Tana, i.e. three sites where different environmental factors come into play were considered. Gelda is a site close to a river inlet (River Gelda), Gedero is a site exposed to strong wind action while Zegie is a secluded site protected by a land mass from any strong wind action. Nematode communities were identified using classification and ordination techniques. The identified communities are then characterised with respect to species composition, biomass, density, diversity, size structure, feeding type and maturity index. Also, the vertical distribution of nematodes is examined at the community and species level. An attempt has been made to associate these variations with the considered environmental factors viz. site, water depth, sediment depth, median grain size and percentage of mud in the sediment.     

On some predatory nematodes from the Okavango Delta,Botswana

Five species of Mononchida and Mononchulus nodicaudatus (v. Daday, 1899) Cobb, 1918 are reported from freshwater sediments at or near Boba Island, Okavango Swamps, Botswana. Illustrations are given for Mylonchulus lacustris (Cobb N.A. in Cobb MX, 1915) Andrássy, 1958, Iotonchus risoceiae (Carvalho, 1955) Andrássy, 1958 and Cobbonchus spec. Two species of Mononchus Bastian, 1865, M. aquaticus Coetzee, 1968 and M. truncatus Bastian, 1865 were also found. The usually rare species M. nodicaudatus was well represented and its juvenile stages are described for the first time.