The Gyratrix hermaphroditus species complex (Kalyptorhynchia: Polycystididae) in marine habitats of eastern Australia

A karyological and morphological analysis of 97 specimens from eastern Australia belonging to the Gyratrix hermaphroditus species complex was performed. Based on karyotype and on details of sclerotized structures of the copulatory organ, the existence of at least eight sibling species in eastern Australia could be recognised. Some of the siblings have a wide distribution across eastern and northern Australia. Populations of wide-ranging species often showed degrees of karyological and morphological differentiation. The diversity of the group is particularly high in tropical Australia. Distribution of siblings appears to be affected by ecological and physical barriers, and determined by sediment texture. This revised version was published online in July 2006 with corrections to the Cover Date.     

Karyometric and morphological analysis of two sympatric marine species of the Gyratrix hermaphroditus complex (Platyhelminthes: Kalyptorhynchia) occurring at Roscoff (Brittany,France)

Two marine sibling species of the Gyratrix hermaphroditus complex were found to occur sympatrically at Roscoff (Brittany, France). Both share the same chromosome number 2n = 6, but differ for the values of centromeric indices, length ratio of chromosomes and absolute length of the haploid genome. Differences were also found in body size and male cuticular apparatus morphology. They are furthermore distinct for the above characters from the other two marine species of the complex already known (from the Mediterranean and the North Sea). Chromosomal evolution and phylogenetical relationships within the marine species of the G. hermaphroditus complex are discussed in detail.     

Characteristics of spermiogenesis and mature spermatozoa in Gyratrix hermaphroditus (Plathelminthes, Rhabdocoela, Kalyptorhynchia)

 Some events of spermiogenesis and the submicroscopic anatomy of male gametes in Gyratrix hermaphroditus are described. Special features occurring during the steps of sperm cell maturation are the development of delicate rootlet-like and spike-shaped structures attached to the basal bodies, an anchor apparatus of cilia staying near the tip of the outgrowing spermatids, the differentiation of a single mitochondrial rod, and the processes of compartmentalizing the chromatin resulting in the formation of extranuclear lamellar stacks. Mature spermatozoa are especially characterized by two incorporated axonemes, a string of large mushroom-shaped dense bodies in the anterior section of the cell, and two lateral rows of nuclear lamellar stacks in the median cell segment. Based on the present findings, the process of spermiogenesis and the organization of spermatozoa in the ground pattern of the monophylum Kalyptorhynchia are reconstructed. Apparently, the sister group of the Kalyptorhynchia can be found within the other free-living and symbiotic Rhabdocoela; the hypothesis of a sister group relationship with the Neodermata is not corroborated. Probably, spermatozoal characteristics can contribute to a discrimination between distinct populations of G. hermaphroditus which is proved to be a complex of several sibling species. Accepted: 25 June 1998     

On the number and spatial distribution of the catecholamine-containing (GA-positive) neurons in some higher and lower turbellarians — a comparison

Original data on the distribution of catecholamines in Provortex karlingi Ax (Rhabdocoela), Microstomum sp. (Macrostomida), and three species of Acoela are presented. Three groups of homologous CA-ergic (catecholaminergic) neurons are discussed: (1) pharyngeal neurons, (2) L-neurons lying postcerebrally in the lateral body regions, and (3) brain neurons. The pharyngeal neurons constitute a synapomorphy of the Rhabditophora. The systematic distribution of the L- and brain neurons, together with the character concerning number of longitudinal nervous trunks, implies that the Catenulida and Rhabditophora are more closely related to each other than to Acoelomorpha. Though these conclusions need confirmation, they show that knowledge of the distribution of neurons containing a given transmitter may be useful for elucidating phylogenetic relationships of lower plathelminths.     

Report on the Polycystididae (Rhabdocoela, Kalyptorhynchia) from Australia, with the Description of Twelve New Species and Six New Genera

Twelve new species of Polycystididae Graff, 1905 are described from the Australian east coast. Nine of them could not be placed in any of the existing genera, and therefore six new genera are erected. Alchoides n. gen. differs from all other polycystidid genera by the presence of a bundle of glands that opens into the distal part of the male atrium (accessory vesicle type V). Two species are included in the genus, A. alchoides n. sp. and A. dittmannae n. sp., which differ from each other in the shape of the stylet. Ametochus gehrkei n. gen n. sp. can be distinguished from other polycystidids by the presence of a prostate vesicle type III associated with a prostate stylet type III, combined with the presence of an accessory stylet type III, while a prostate stylet type II is lacking. Typical for Arrawarria inexpectata n. gen n. sp. is the combined presence of an armed cirrus with a prostate vesicle type II connected to a prostate stylet type II. Two species are assigned to the new genus Duplexostylus n. gen.: D. rowei n. sp. and D. winsori n. sp. These two species have two unique features: a prostate vesicle type IV directly connected to a prostate stylet type III and an asymmetrical septum that surrounds the proximal part of the male atrium. They can be distinguished from each other by differences in the detailed construction of their stylets. Two new species are placed in the new genus Stradorhynchus n. gen.: S. caecus n. sp. and S. terminalis n. sp. They have unpaired gonads and a prostate vesicle type IV connected to a prostate stylet type IV, which combination of characters makes them unique within the Polycystididae. The two species differ from each other in the shape and size of the stylet. Triaustrorhynchus armatus n. gen., n. sp. is the first species of the Polycystididae to have three types of stylet in the male atrium: a prostate stylet type II, a prostate stylet type III and an accessory stylet type III. Three new species could be placed in existing genera: Cincturorhynchus monaculeus n. sp., Paraustrorhynchus caligatus n. sp. and Polycystis australis n. sp. All three differ from their congeners in the form and dimensions of their stylets. All newly described species are discussed, giving their similarities and differences with resembling species. Austrorhynchus hawaiiensis Karling, 1977 is reported for the first time in Australia, and the Australian population is compared with populations from other regions. The presence of Gyratrix hermaphroditus Ehrenberg, 1831, one new species of Paulodora Marcus, 1948 and a new genus of Typhlopolycystidinae Evdonin, 1977 is mentioned.     

Localization and distribution of catecholaminergic structures in the nervous system of Phocanema decipiens (nematoda)

The nervous system of Phocanema decipiens was examined with both the formaldeyhyde-induced and the glyoxylic acid fluorescence histochemical techniques. Green catecholaminergic structures were observed in 4 cephalic papillary nerves, 2 fibres with varicosities in the nerve ring as well as the ventral nerve cord and a pair of lateral nerves.The papillary nerves, extending from the nerve ring to the lips region, have cell bodies which are located anterior or adjacent to the nerve ring. Cell bodies of the lateral nerves are found within the lateral cord tissue posterior to the nerve ring. Each of these neurons has 3 processes—one joins with the nerve ring, the other merges with the ventral nerve cord and the third ends abruptly within the lateral cord.     

Ultrastructure of the Stylet Protractor Muscle in Gyratrix hermaphroditus (Turbellaria,Rhabdocoela)

The subsarcolemmal cisternae of the sarcoplasmic reticulum form peripheral couplings with the sarcolemma. The junctional gap is crossed by periodic densities called junctional processes. Desmosomes provide mechanical coupling between the myofibres. Hemidesmosomes connect the myofibre with a well developed connective tissue sheath.     

The Ultrastructure of the Nervous System of Gyratrix hermaphroditus (Turbellaria, Rhabdocoela)

The peripheral nervous system and the synapses of G. hermaphroditus are studied with the electron microscope. There is a submuscular as well as a subepithelial plexus. The subepithelial plexus is found among the muscles and between the muscles and the basement membrane. It consists of fibres containing large lucent and lysosome-like vesicles and fibres with only small lucent (synaptic) vesicles. In the deeper lying submuscular plexus also dense and dense-cored vesicles occur in the fibres. Cell bodies are not observed in the plexuses. The separate nerve supplies of the pharynx and the gonads contain nerve cells of the neurosecretory type. Fibres of the same kinds as in the brain are also seen here. The synapses in the neuropile are of two kinds. 1. Symmetrical synapses with an additional presynaptic network are most common. 2. Synapses without thickenings of membranes are observed between lateral membranes of neurites. In the peripheral nervous system are two other kinds of synapses also observed. 1. Asymmertical synapses with a denser and wider postsynaptic thickening and 2. neuromuscular junctions. Neurites containing accumulations of small vesicles against the basement membrane are also described. The organization of the peripheral nervous system is described and discussed in relation to the systematic position of G. hermaphroditus.     

Chromosomal evolution and speciation in the Gyratrix hermaphroditus species complex (Platyhelminthes,Kalyptorhynchia): karyometric and morphological analyses of fifteen fresh-water populations from Western Europe

Fifteen fresh-water populations of the Gyratrix hermaphroditus species complex from Western Europe (Italy, Spain, France) were karyometrically analysed. All shared the same chromosome number 2n = 4. Three distinct karyotypes were recognized on the basis of the different values of the centromeric index of chromosome 2, respectively metacentric, intermediate between meta- and submetacentric, and sub-telocentric. The morphology of chromosome 1 (an isobrachial metacentric) and the length ratio of chromosomes were on the contrary constant in all the populations investigated.Differences in the size of male cuticular organs were observed accompanying the karyological differentiation.The fifteen populations are interpreted as representing at least three sibling-species.Chromosomal evolution and phylogenetical relationships with the marine species of the Gyratrix hermaphroditus complex are discussed.     

Anatomy and Systematics of Some Polycystididae (Turbellaria, Kalyptorhynchia) from the Pacific and S. Atlantic

Paraustrorhynchus gen.n., P. pacificus sp.n. (California), Antiboreorhynchus novzelae sp.n. (New Zealand) and Gyratrix proaviformis sp.n. (Oregon) are described as new taxa. Additional notes are given on Gyratrix hermaphroditus Ehrbg. (new localities on the N. American Pacific coast), Scanorhynchus forcipatus Karling (new locality in California), Paraustrorhynchus elixus (Marcus) comb.n. and Alcha evelinae Marcus (new localities in California). The taxonomy of the genera and species is discussed. Viewpoints are presented on evolutionary trends and homologous atrial organs in the family Polycystididae.     

Antigenicity to neuropeptide F (NPF) in Stenostomum leucops and Microstomum lineare

The first native flatworm regulatory peptide, neuropeptide F (NPF) has recently been isolated and sequenced from the cestode Moniezia expansa (see Maule et al., 1991) and the turbellarian Artioposthia triangulata, (see Curry et al., 1992). NPF belongs to the neuropeptide Y (NPY) superfamily and the antiserum is known to show cross-reactivity to the vertebrate neuropeptides of the NPY superfamily. It terminates in RFamide, like the invertebrate neuropeptides FMRFamide and RFamide, and may cross-react with neuropeptides of the FMRFamide family. Strong immunoreactivity (IR) to FMRF- and RF-amide has been demonstrated in members of most flatworm groups. In the present study, IR to NPF (diluted 1:1000) is demonstrated in Stenostomum leucops (Catenulida) and Microstomum lineare (Macrostomida). The controls included: omitting primary antibody, using non-immune serum and liquid-phase absorption with the homologous antigen (1000 ng ml^–1). The NPF IR pattern was compared to the FMRF and RF-amide IR patterns in order to reveal differences or co-localization. In addition, the sequential appearance of NPF-positive cells in developing zooids was followed and double staining with a-5-HT made to complete the study.     

Karyology of a marine population of Gyratrix hermaphroditus (Turbellaria,Rhabdocoela) and chromosomal evolution in this species complex

Karyology and reproductive biology of a marine population of the species complex Gyratrix hermaphroditus, from Roscoff (Brittany, France), have been investigated. A diploid complement of six chromosomes was determined from spermatogonial mitotic figures. One chromosome pair is metacentric, the second is intermediate between meta- and submetacentric, and the third is subtelocentric.In this population, regular meiosis occurs in both female and male germ lines, and the animals reproduce only by means of amphimictic eggs. Certain specimens of the population showed the elimination of one of the three bivalents during the first meiotic division in spermatogenesis. It seems that such animals produce normal and aneuploid sperm simultaneously; the aneuploid sperm are not capable of fertilization.The Roscoff population differs in its karyotype (2n = 6) from freshwater populations, which are either diploid (2n = 4) or polyploid (3n = 6, 4n = 8). These results suggest that aneuploidy played a role in the differentiation of freshwater populations from an originally marine species complex.     

Substance P immunoreactivity in sensory structures and the central and pharyngeal nervous system of Stenostomum leucops (Catenulida) and Microstomum lineare (Macrostomida)

Immunoreactivity (IR) obtained by monoclonal antibodies to substance P (SP) was studied in the asexually reproducing microturbellarians Stenostomum leucops and Microstomum lineare. The IR pattern was studied by confocal and ordinary fluorescence microscopy. In both species, IR occurs in the brain in peripheral cells, neuropilar fibres, in longitudinal cords and in the pharyngeal nervous system. The IR patterns reveal neuroanatomical details not observed with other neuroactive substances. In both species, immunopositive cells send fibers to the ciliary pits. In M. lineare, additional fibres run to more frontally located sensory structures. In S. leucops, two pharyngeal nerve rings are visualized. The pharyngeal nerve ring close to the surface associated with symmetrical immunopositive cell pairs is demonstrated for the first time, while the deeper-lying pharyngeal nerve ring has been previously demonstrated by antibodies to the molluscan cardioactive peptide FMRF-amide. Two cells with strong IR are connected by short fibres to the pharyngeal nerve ring in M. lineare. In the developing new individuals, i.e., the zooids of M. lineare, IR to SP is first revealed in nerve fibres growing out from parental lateral nerve cords towards the centre of the worm where the new brain commissure will appear. Immunopositive cells in the brain periphery and close to the developing ciliary pits appear later. Simultaneous staining by antibodies to SP and 5-HT shows that IR to SP appears later than IR to 5-HT.     

Myoanatomy and serotonergic nervous system of plumatellid and fredericellid phylactolaemata (lophotrochozoa,ectoprocta)

The phylogenetic position of the Ectoprocta within the Lophotrochozoa is discussed controversially. For gaining more insight into ectoproct relationships and comparing it with other potentially related phyla, we analysed the myoanatomy and serotonergic nervous system of adult representatives of the Phylactolaemata (Plumatella emarginata, Plumatellavaihiriae, Plumatella fungosa, Fredericella sultana). The bodywall contains a mesh of circular and longitudinal muscles. On its distal end, the orifice possesses a prominent sphincter and continues into the vestibular wall, which has longitudinal and circular musculature. The tentacle sheath carries mostly longitudinal muscle fibres in Plumatella sp., whereas F. sultana also possesses regular circular muscle fibres. Three groups of muscles are associated with the lophophore: 1) Lophophoral arm muscles (missing in Fredericella), 2) epistome musculature and 3) tentacle musculature. The epistome flap is encompassed by smooth muscle fibres. A few fibres extend medially over the ganglion to its proximal floor. Abfrontal tentacle muscles have diagonally arranged muscle fibres in their proximal region, whereas the distal region is formed by a stack of muscles that resemble an inverted ‘V’. Frontal tentacle muscles show more variation and either possess one or two bases. The digestive tract possesses circular musculature which is striated except at the intestine where it is composed of smooth muscle fibres. The serotonergic nervous system is concentrated in the cerebral ganglion. From the latter a serotonergic nerve extends to each tentacle base. In Plumatella the inner row of tentacles at the lophophoral concavity lacks serotonergic nerves. Bodywall musculature is a common feature in many lophotrochozoan phyla, but among other filter feeders like the Ectoprocta is only present in the ‘lophophorate’ Phoronida. The longitudinal tentacle musculature is reminiscent of the condition found in phoronids and brachiopods, but differs to entoproct tentacles. Although this study shows some support for the ‘Lophophorata’, more comparative analyses of possibly related phyla are required. J. Morphol., 2011. © 2011 Wiley Periodicals, Inc.     

Serotonin in the nervous system of the head region of the land planarian Bipalium kewense

The presence and distribution of serotonin (5-hydroxytryptamine, or 5-HT) in the head region of the land planarian Bipalium kewense has been investigated by an indirect immunofluorescence technique combined with confocal scanning laser microscopy (CSLM), and also by immunogold labeling at ultrastructural level. Serotonin immunoreactivity (IR) was restricted to elements of the nervous system, such as the cerebral ganglion, and the peripheral nerve net. Most of 5-HT-immunoreactive neurons are at the periphery of the brain; they were identified as unipolar, bipolar, and multipolar neurons. The ultrastructural results using immunogold labeling confirm the location of 5-HT within electron-dense vesicles (50-120 nm in diameter), clustered both in the cell bodies and in their processes. The intense 5-HT-IR herein demonstrated for B. kewense adds new data to the poorly studied nervous system of land planarians.     

Establishment and characterization of induced pluripotent stem cells (iPSCs) from central nervous system lupus erythematosus

Involvement of the central nervous system (CNS) is an uncommon feature in systemic lupus erythematosus (SLE), making diagnosis rather difficult and challenging due to the poor specificity of neuropathic symptoms and neurological symptoms. In this work, we used human‐induced pluripotent stem cells (hiPSCs) derived from CNS‐SLE patient, with the aim to dissect the molecular insights underlying the disease by gene expression analysis and modulation of implicated pathways. CNS‐SLE‐derived hiPSCs allowed us to provide evidence of Erk and Akt pathways involvement and to identify a novel cohort of potential biomarkers, namely CHCHD2, IDO1, S100A10, EPHA4 and LEFTY1, never reported so far. We further extended the study analysing a panel of oxidative stress‐related miRNAs and demonstrated, under normal or stress conditions, a strong dysregulation of several miRNAs in CNS‐SLE‐derived compared to control hiPSCs. In conclusion, we provide evidence that iPSCs reprogrammed from CNS‐SLE patient are a powerful useful tool to investigate the molecular mechanisms underlying the disease and to eventually develop innovative therapeutic approaches.     

Ultrastructure of the Epithelium and the Sensory Receptors in the Body Wall, the Proboscis and the Pharynx of Gyratrix hermaphroditus (Turbellaria, Rhabdocoela)

The epidermis of Gyratrix hermaphroditus can be described as semi-syn-cytial. Its ultrastructure is characterized by microvilli and cilia with two strong rootlets perpendicular to each other. The apical part of the epithelium contains mitochondria and vacuoles. The basal synthesizing layer is provided with cell boundaries, at least between the type II penetrating receptors in the anterior and posterior end of the worm. Four different types of sensory receptors are described. The type I receptor has a protruding cilium-bearing process and is found all over the body. The type II receptor is found in the anterior and posterior end and has a retracted process with a kinocilium surrounded by eight stereocilia. The type III receptor bears a balloon-shaped modified cilium and is located at the anterior end. The type IV receptor has a short cilium with an unstable ciliary membrane and occurs in the proboscis epithelium as well as in the pharynx epithelium. Phylogenetical aspects of the semi-syncytial epithelium and functional aspects of the sensory receptors are discussed.     

Calcitonin gene-related peptide acts within the central nervous system to inhibit gastric acid secretion

The central nervous system effect of calcitonin gene-related peptide (CGRP) on gastric acid secretion was studied in conscious freely moving rats. CGRP (220 fmol to 2.2 nmol) injected into the lateral cerebral ventricle or intravenously inhibited gastric acid secretion. Intravenous passive immunization with CGRP antiserum prevented the inhibitory effect of CGRP following intravenous but not intracerebroventricular administration. Adrenalectomy and noradrenergic blockade with bretylium tosylate did not significantly alter the inhibitory action of CGRP given intracerebroventricularly on gastric secretion. These studies indicate that CGRP acts within the central nervous system to potently decrease gastric acid secretion by mechanism(s) not dependent on intact sympathetic nervous function.     

先天性CMV感染致中枢神经系统畸形发育机制

胎儿中枢神经系统(central nervous system,CNS)是人类巨细胞病毒(human cytomegalovirus,HCMV)先天性感染的主要靶器官。胚胎期CMV感染常常导致严重CNS畸形的发生,其前提条件是CNS中的神经前体(干)细胞、神经元及神经胶质细胞对CMV普遍易感。发育期CNS感染CMV具有以下特点:⑴神经系统细胞对CMV的容纳性在CNS的不同发育阶段有所不同;⑵受累的细胞数随着发育的进展而增多;⑶CNS不同部位的细胞对CMV的敏感性存在明显的差异;⑷感染发生时细胞所处细胞周期的时相也与感染严重程度密切相关。CMV感染能诱导宿主细胞特异性的染色体折断,影响Homeobox基因(胚胎发育的主控基因)的表达,进而阻断细胞周期(G1期滞留)、诱导细胞凋亡,导致CNS细胞数量减少与迁徙异常,最终导致C N S发育畸形。