bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of metabotropic glutamate receptors in rat meningeal and brain microvasculature and choroid plexus
Authors: Gillard Samantha E. , Tzaferis John , Tsui Ho‐Ching Tiffany , Kingston Ann E.
Published: May 2003

This study investigated the distribution of metabotropic glutamate receptors (mGluRs) in meningeal and parenchymal microvasculature and in choroid plexus by means of Western blot analysis and immunohistochemistry. Western blot analysis demonstrated mGluR expression in both rat and human leptomeningeal tissues. In the rat, mGluR expression was developmentally regulated, with only mGluR2/3 showing expression at the embryonic day 19 developmental stage. In contrast, mGluR1α, mGluR2/3, mGluR4a, and mGluR7 were expressed in leptomeninges from adult rats. Immunohistochemical analyses showed intense mGluR1α immunoreactivity in the pia mater and blood vessels in the subarachnoid space and in the arachnoid layer of the meninges. mGluR2/3, mGluR4a, mGluR5, and mGluR7 were also expressed in meningeal microvasculature. In addition, the parenchymal microvasculature and choroid plexus were strongly immunoreactive for mGluR1α, mGluR2/3, mGluR4a, mGluR5, and mGluR7. We used antibodies specific for phenotypic markers of microvascular and glial cells to characterize the cell type(s) immunopositive for mGluRs. Comparison of staining with anti–von Willebrand factor antibody and anti‐mGluR antibodies revealed that mGluR immunoreactivity was present in cells that surrounded the luminal surface labeled by the endothelial cell marker. In these cells, smooth muscle actin and mGluR immunoreactivity overlapped, suggesting that, in addition to endothelial cells, pericytes within the microvasculature also express mGluRs. Furthermore, expression of mGluR1α was also observed in pure pericyte cultures isolated from bovine retina. These data suggest that glutamate by means of activation of mGluRs may have a broad sphere of physiological influence in the brain which in addition to modulating synaptic transmission may also have a role in determining microvascular function and dysfunction. J. Comp. Neurol. 461:317–332, 2003. © 2003 Wiley‐Liss, Inc.
Ontogeny of ultraviolet‐sensitive cones in the retina of rainbow trout (Oncorhynchus mykiss)
Authors: Allison W. Ted , Dann Stephen G. , Vidar Helvik Jon , Bradley Clarrisa , Moyer Heather D. , Hawryshyn Craig W.
Published: May 2003

In order to facilitate emerging models of retinal development, we developed electroretinogram and in situ hybridization protocols to examine the ontogeny of photoreceptors in the retina of a land‐locked salmonid, the rainbow trout (Oncorhynchus mykiss). We cloned cDNA fragments corresponding to the rod opsin and each of the four cone opsin gene families, which we utilized to produce riboprobes. We established the specificity of the in situ hybridization protocol by examining subcellular signal localization and through double‐labeling experiments. We confirm the assumption that the accessory corner cones in the square mosaic are the ultraviolet wavelength‐sensitive (UVS) cone photoreceptor (i.e., they express an SWS1 opsin) and observed UVS cones throughout the retina of small trout. Larger fish have a decrease in sensitivity to short wavelength light stimuli and the distribution of UVS cones in the mature retina is limited to the dorsal‐temporal quadrant. These larger fish also possess differentiated UVS cones in the peripheral germinal zone (PGZ), including within areas peripheral to mature retina lacking UVS cones. These data are consistent with the loss of putative UVS cones from the PGZ of a migratory salmonid of another genus, and thus the disappearance of UVS cones appears to be general to the Family Salmonidae, regardless of life history strategy. The generation, differentiation, and subsequent loss of UVS cones in the smolt PGZ is a dramatic example of the supposition that the mechanisms of PGZ development recapitulate the retinal embryogenesis of that species. J. Comp. Neurol. 461:294–306, 2003. © 2003 Wiley‐Liss, Inc.
Expression of the genes GAD67 and Distal‐less‐4 in the forebrain of Xenopus laevis confirms a common pattern in tetrapods
Authors: Brox Aurora , Puelles Luis , Ferreiro Beatriz , Medina Loreta
Published: May 2003

We investigated whether γ‐amino butyric acidergic (GABAergic) cell populations correlate positionally with specific Dlx‐expressing histogenetic territories in an anamniote tetrapod, the frog Xenopus laevis. To that end, we cloned a fragment of Xenopus GAD67 gene (xGAD67, expressed in GABAergic neurons) and compared its expression with that of Distal‐less‐4 gene (xDll‐4, ortholog of mouse Dlx2) in the forebrain at late larval and adult stages. In Xenopus, GABAergic neurons were densely concentrated in xDll‐4–positive territories, such as the telencephalic subpallium, part of the hypothalamus, and ventral thalamus, where nearly all neurons expressed both genes. In contrast, the pallium of Xenopus generally contained dispersed neurons expressing xGAD67 or xDll‐4, which may represent local circuit neurons. As in amniotes, these pallial interneurons may have been produced in the subpallium and migrated tangentially into the pallium during development. In Xenopus, the ventral division of the classic lateral pallium contained extremely few GABAergic cells and showed only low signal of the pallial gene Emx1, suggesting that it may represent the amphibian ventral pallium, homologous to that of amniotes. At caudal forebrain levels, a number of GABAergic neurons was observed in several areas (dorsal thalamus, pretectum), but no correlation to xDll‐4 was observed there. The location of GABAergic neurons in the forebrain and their relation to the developmental regulatory genes Dll and Dlx were very similar in Xenopus and in amniotes. The close correlation in the expression of both genes in rostral forebrain regions supported the notion that Dll/Dlx are among the genes involved in the acquisition of the GABAergic phenotype. J. Comp. Neurol. 461:370–393, 2003. © 2003 Wiley‐Liss, Inc.
Characterization of the cDNA encoding a somatostatin variant in the chicken brain: Comparison of the distribution of the two somatostatin precursor mRNAs
Authors: Trabucchi Michele , Tostivint Hervé , Lihrmann Isabelle , Blähser Sabine , Vallarino Mauro , Vaudry Hubert
Published: May 2003

Although the existence of two somatostatin variants (SS1 and SS2) has now been demonstrated in the brain of mammals, amphibians, and fish, only one isoform of somatostatin (SS1) has been characterized to date in the brain of birds. Here we report cloning of the cDNA encoding a 101‐amino‐acid protein (PSS2) that encompasses the somatostatin variant [Pro2]somatostatin‐14 (SS2) at its C‐terminus. Sequence analysis indicated that chicken PSS2 is more closely related to fish PSS2 than to mammalian cortistatin precursors. Northern blot analysis showed that the chicken PSS1 gene is expressed in the central nervous system (CNS) and in the pancreas, whereas the PSS2 gene is expressed only in the CNS and not in peripheral organs. In situ hybridization histochemistry revealed that, in the chicken brain, PSS1 mRNA is more widely distributed than PSS2 mRNA. In particular, PSS1 mRNA expression was found in the hippocampus, the hyperstriatum, the preoptic area, the ventricular hypothalamic nuclei, the optic tectum, and several nuclei of the mesencephalon and rhombencephalon. In contrast, the distribution of PSS2 mRNA was restricted to a few regions of the brain, including the paraolfactory lobe, the paleostriatum, and some nuclei of the mesencephalon and rhombencephalon. The fact that the PSS1 and PSS2 genes are differently expressed in the brain and in peripheral organs indicates that, in chicken, the two somatostatin variants likely exert distinct functions. In particular, the observation that PSS1 mRNA, but not PSS2 mRNA, occurs in the preoptic area and in the ventral hypothalamic nuclei suggests that, of the two somatostatin isoforms, only SS1 acts as a hypophysiotropic factor. J. Comp. Neurol. 461:441–451, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of neuropeptide Y immunoreactivity in the central and peripheral nervous systems of amphioxus (Branchiostoma lanceolatum Pallas)
Authors: Castro Antonio , Manso María Jesús , Anadón Ramón
Published: May 2003

Immunocytochemistry techniques were employed to investigate the distribution of neuropeptide Y‐like‐immunoreactive (NPY‐ir) cells and fibers in the central and peripheral nervous systems of adult amphioxus. NPY‐ir neurons of the commissural type were abundant in the brain and present but more scarce in the spinal cord. These neurons gave rise to conspicuous NPY‐ir tracts that coursed along the entire length of the nerve cord. Some fibers exhibited conspicuous Herring body‐like swellings. In the peripheral nervous system, small NPY‐ir neurons and a large number of thin, beaded NPY‐ir fibers were observed in the atrial region, indicating the involvement of this substance in visceral regulation. A few NPY‐ir fibers, possibly afferent to the spinal cord, coursed in the ventral branches of the spinal nerves of this region, whereas no NPY‐ir fibers coursed in the preoral or velar nerves or in the dorsal branches of the other spinal nerves. These results indicate that NPY is widely used as a neuroregulator/neurotransmitter in the central and peripheral nervous systems of this primitive chordate. In addition, this study demonstrates the presence of tall, thin NPY‐ir cells in the putative adenohypophyseal homologue, the Hatschek's pit organ, which is located in the roof of the preoral cavity (vestibule). J. Comp. Neurol. 461:350–361, 2003. © 2003 Wiley‐Liss, Inc.
Synaptic targets of commissural interneurons in the lumbar spinal cord of neonatal rats
Authors: Birinyi András , Viszokay Kornél , Wéber Ildikó , Kiehn Ole , Antal Miklós
Published: May 2003

There is strong evidence that commissural interneurons, neurons with axons that extend to the contralateral side of the spinal cord, play an important role in the coordination of left/right alternation during locomotion. In this study we investigated the projections of commissural interneurons to motor neurons and other commissural interneurons on the other side of the spinal cord in neonatal rats. To establish whether there are direct contacts between axons of commissural interneurons and motor neurons, we carried out two series of experiments. In the first experiment we injected biotinylated dextran amine (BDA) into the lateral motor column to retrogradely label commissural interneurons that may have direct projections to motor neurons. Stained neurons were recovered in the ventromedial areas of the contralateral gray matter in substantial numbers. In the second experiment BDA was injected into the ventromedial gray matter on one side of the lumbar spinal cord, whereas motor neurons were simultaneously labeled on the opposite side by applying biocytin onto the ventral roots. BDA injections into the ventromedial gray matter labeled a strong axon bundle that arose from the site of injection, crossed the midline in the ventral commissure, and extensively arborized in the contralateral ventral gray matter. Many of these axons made close appositions with dendrites and somata of motor neurons and also with commissural interneurons retrogradely labeled with BDA. The results suggest that commissural interneurons may establish monosynaptic contacts with motor neurons on the opposite side of the spinal cord. Our findings also indicate that direct reciprocal connections between commissural interneurons on the two sides of the spinal cord may also exist. J. Comp. Neurol. 461:429–440, 2003. © 2003 Wiley‐Liss, Inc.
Quantitative trait loci modulate ventricular size in the mouse brain
Authors: Zygourakis Corinna C. , Rosen Glenn D.
Published: May 2003

Cerebral ventricular size in humans varies significantly. Abnormal enlargement of the ventricles has been associated with schizophrenia, and hydrocephalus can lead to serious cognitive and motor deficiencies in humans and animals. In this study, we mapped quantitative trait loci (QTLs) modulating cerebroventricular size in mice. We hypothesized that genes underlying hydrocephalus might also modulate normal variation in ventricular size. By using digital images of mouse brain sections and stereological techniques, we estimated the volume of the combined lateral and third ventricles, as well as the volume of the entire brain, in 228 AXB and BXA recombinant inbred mice and their parent strains (A/J and C57BL/6J). Ventricle size, expressed as percentage of brain volume, is a heritable trait (h2= 0.32). We detected a major QTL controlling variance in volume on chromosome (Chr) 8 near the markersD8Mit94andD8Mit189. We also detected a strong epistatic interaction affecting ventricular volume between loci on Chr 4 (nearD4Mit237andD4Mit214) and on Chr 7 (D7Mit178andD7Mit191). These three QTLs, labeledVent8a,Vent4b, andVent7c, are close to genes that have been previously implicated in hydrocephalus. J. Comp. Neurol. 461:362–369, 2003. © 2003 Wiley‐Liss, Inc.
Abnormal cerebellar histogenesis in PEX2 Zellweger mice reflects multiple neuronal defects induced by peroxisome deficiency
Authors: Faust Phyllis L.
Published: May 2003

The form and circuitry of the cerebellum develops by a complex process that requires integration of afferent–target interactions between multiple neuronal populations and migratory patterns established by neuron–glial interactions. Analysis of mice lacking the PEX2 peroxisome assembly gene, in which peroxisomal function is disrupted, reveals abnormal cerebellar histogenesis due to the disturbance of multiple cellular processes within neurons. Defects in cerebellar growth and the rostro‐caudal foliation pattern reflect a reduced granule neuron population and abnormal Purkinje cell dendrite development. In granule neurons, there is increased apoptotic cell death and delayed movement from the EGL to IGL that reflects cell cycle, maturational and migrational abnormalities. The underlying Purkinje cells have stunted dendrite arbors with abnormal branching patterns, which may reflect altered inductive influences from the delayed granule neuron translocation. A delayed arborization of mutant olivary climbing fibers and their defective translocation from the perisomatic to the dendritic compartment of Purkinje cells results in numerous spines on the soma and proximal dendrites of Purkinje cells. Distal Purkinje cell dendritic spines also display abnormal morphology. These Purkinje cell dendritic abnormalities are seen in association with persistent and enlarged axonal spheroids, further indicating the presence of a degenerative process within the Purkinje cell. This PEX2−/− mouse model for the human peroxisomal biogenesis disorder Zellweger syndrome illustrates the complex interplay of abnormal developmental processes in the cerebellum and the importance of peroxisomal function for neuronal migration, proliferation, differentiation, and survival. J. Comp. Neurol. 461:394–413, 2003. © 2003 Wiley‐Liss, Inc.
Patterns of expression of neuropeptides in GABAergic nonprincipal neurons in the mouse hippocampus: Quantitative analysis with optical disector
Authors: Jinno Shozo , Kosaka Toshio
Published: May 2003

Neuropeptides are widely distributed in the central nervous system and are considered to play important roles in the regulation of neuronal activity. This study shows the patterns of expression of four neuropeptides [neuropeptide Y (NPY), somatostatin (SOM), cholecystokinin (CCK), and vasoactive intestinal polypeptide (VIP)] in γ‐aminobutyric acid (GABA)‐ergic neurons of the mouse hippocampus, with particular reference to the areal and dorsoventral difference. First, we estimated the numerical densities (NDs) of GABAergic neurons containing these neuropeptides using the optical disector. The NDs of NPY‐ and SOM‐positive GABAergic neurons were generally higher than those of CCK‐ and VIP‐positive GABAergic neurons. In the whole area of the hippocampus, the ND of NPY‐positive GABAergic neurons showed no significant dorsoventral difference (1.90 × 103/mm3 in the dorsal level, 2.09 × 103/mm3 in the ventral level), whereas the ND of SOM‐positive GABAergic neurons was higher in the ventral level (1.44 × 103/mm3) than in the dorsal level (0.80 × 103/mm3). The ND of CCK‐positive GABAergic neurons was also higher in the ventral level (0.57 × 103/mm3) than in the dorsal level (0.33 × 103/mm3). Similarly, the ND of VIP‐positive GABAergic neurons was higher in the ventral level (0.61 × 103/mm3) than in the dorsal level (0.43 × 103/mm3). Next, we calculated the proportions of GABAergic neurons containing these neuropeptides among the total GABAergic neurons. In the whole area of the hippocampus, NPY‐, SOM‐, CCK‐, and VIP‐positive neurons accounted for about 31%, 17%, 7%, and 8% of GABAergic neurons, respectively. The present data establish a baseline for examining potential roles of GABAergic neurons in the hippocampal network activity in mice. J. Comp. Neurol. 461:333–349, 2003. © 2003 Wiley‐Liss, Inc.
Developmental change in expression and subcellular localization of two Shaker‐related potassium channel proteins (Kv1.1 and Kv1.2) in the chick tangential vestibular nucleus
Authors: Popratiloff Anastas , Giaume Christian , Peusner Kenna D.
Published: May 2003

The chick tangential nucleus is a major avian vestibular nucleus whose principal cells participate in two vestibular reflexes. Intracellular recordings have shown that the principal cells acquire their mature firing pattern gradually during development. At embryonic day 16 (E16), most principal cells fire a single spike, whereas shortly after hatching (H) the vast majority fire repetitively on depolarization. The transition in firing pattern was likely due in part to a downregulation of a low‐threshold, sustained, dendrotoxin‐sensitive (DTX) potassium current, IDS. Since the DTX‐sensitive potassium channel subunits Kv1.1 and Kv1.2 generate sustained currents, in the present study we applied fluorescence immunocytochemistry and confocal microscopy to characterize their developmental expression at E16, H1, and H9. At E16, both Kv1.1 and Kv1.2 staining were confined to the principal cell bodies. Immunolabeling decreased significantly for both proteins at H1, and more so by H9. Double‐labeling with a monoclonal antibody against microtubule‐associated protein 2 (MAP2) in hatchlings showed that some Kv1.1 remained as clusters within the cell body, at the base of the dendrites, and in the axon initial segment. In hatchlings, Kv1.2 staining decreased in the cell bodies and simultaneously appeared in the neuropil, colocalized with biocytin‐labeled primary vestibular fibers and vestibular “spoon” terminals. Also, double‐labeling with synaptotagmin showed that Kv1.2 colocalized with many nonvestibular terminals surrounding the principal cell bodies. These results identified developmental decreases in the staining of these two potassium channel protein subunits and changes in their subcellular localization corresponding to the downregulation of IDS defined electrophysiologically around hatching. Accordingly, both of these protein subunits could be involved in regulating excitability of the principal cells. J. Comp. Neurol. 461:466–482, 2003. © 2003 Wiley‐Liss, Inc.
Autoradiographic analysis of rat brain kinin B1 and B2 receptors: Normal distribution and alterations induced by epilepsy
Authors: Ongali Brice , Campos Maria Martha , Bregola Gianni , Rodi Donata , Regoli Domenico , Thibault Gaétan , Simonato Michele , Couture Réjean
Published: May 2003

Kindling‐induced seizures constitute an experimental model of human temporal lobe epilepsy that is associated with changes in the expression of several inflammatory proteins and/or their receptors in distinct brain regions. In the present study, alterations of kinin receptors in the brain of amygdaloid‐kindled rats were assessed by means of in vitro autoradiography, using 125I‐labeled 3‐4 hydroxyphenyl‐propionyl‐desArg9‐D‐Arg°‐[Hyp3, Thi5, D‐Tic7, Oic8]‐bradykinin (B1 receptors) and 125I‐labeled 3‐4 hydroxyphenyl‐propionyl‐D‐Arg°‐[Hyp3, Thi5, D‐Tic7, Oic8]‐bradykinin (B2 receptors) as ligands. Results demonstrate that B2 receptors are widely distributed throughout the brain of control rats. The highest densities were observed in lateral septal nucleus, median preoptic nucleus, dentate gyrus, amygdala, spinal trigeminal nucleus, mediovestibular nucleus, inferior cerebellar peduncles, and in most of cortical regions (0.81–1.4 fmol/mg tissue). In contrast, very low densities of B1 receptors were detected in all analyzed areas from control rats (0.18–0.26 fmol/mg tissue). When assessed in kindled rats, specific binding sites for B2 receptors were significantly decreased (41 to 76%) in various brain areas. Conversely, B1 receptor binding sites were markedly increased in kindled rats, especially in hippocampus (CA2 ≅ CA1 ≅ CA3), Amy and entorhinal, peririnal/piriform, and occipital cortices (152–258%). Data show for the first time that kindling‐induced epilepsy results in a significant decline of B2 receptor binding sites, accompanied by a striking increase of B1 receptor labeling in the rat brain. An altered balance between B1 and B2 receptor populations may play a pivotal role in the onset and/or maintenance of epilepsy. J. Comp. Neurol. 461:506–519, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of NTS3 receptor/sortilin mRNA and protein in the rat central nervous system
Authors: Sarret Philippe , Krzywkowski Pascale , Segal Laura , Nielsen Morten S. , Petersen Claus M. , Mazella Jean , Stroh Thomas , Beaudet Alain
Published: May 2003

The neurotensin (NT) receptor, NTS3, originally identified as the intracellular sorting protein sortilin, is a member of a recently discovered family of receptors characterized by a single transmembrane domain. The present study provides the first comprehensive description of the distribution of NTS3/sortilin mRNA and protein in adult rat brain using in situ hybridization and immunocytochemistry. Both NTS3/sortilin mRNA and immunoreactivity displayed a widespread distribution throughout the brain. High levels of NTS3/sortilin expression and immunoreactivity were found in neuronal cell bodies and dendrites of allocortical areas such as the piriform cortex and hippocampus. Regions expressing both high levels of NTS3/sortilin mRNA and protein also included several neocortical areas, the islands of Calleja, medial and lateral septal nuclei, amygdaloid nuclei, thalamic nuclei, the supraoptic nucleus, the substantia nigra, and the Purkinje cell layer of the cerebellar cortex. In the brainstem, all cranial nerve motor nuclei were strongly labeled. NTS3/sortilin mRNA and immunoreactivity were also detected over oligodendrocytes in major fiber tracts. Subcellularly, NTS3/sortilin was predominantly concentrated over intracytoplasmic membrane‐bound organelles. Many of the areas exhibiting high levels of NTS3/sortilin (e.g., olfactory cortex, medial septum, and periaqueductal gray) have been documented to contain high concentrations of NT nerve cell bodies and axons, supporting the concept that NTS3/sortilin may play a role in NT sorting and/or signaling. Other areas (e.g., hippocampal CA fields, cerebellar cortex, and cranial nerve motor nuclei), however, are NT‐negative, suggesting that NTS3/sortilin also exerts functions unrelated to NT signaling. J. Comp. Neurol. 461:483–505, 2003. © 2003 Wiley‐Liss, Inc.
Immunohistochemical distribution of NTS2 neurotensin receptors in the rat central nervous system
Authors: Sarret Philippe , Perron Amélie , Stroh Thomas , Beaudet Alain
Published: May 2003

In the present study, we localized the levocabastine‐sensitive neurotensin receptor (NTS2) protein in adult rat brain by using an N‐terminally‐directed antibody. NTS2‐like immunoreactivity was broadly distributed throughout the rat brain. At the cellular level, the reaction product was exclusively associated with neurons and predominantly, although not exclusively, with their dendritic arbors. No NTS2 signal was observed over astrocytes, as confirmed by dual confocal microscopic immunofluorescence studies using the astrocytic marker S100β. High densities of NTS2‐like immunoreactive nerve cell bodies and/or processes were detected in many regions documented to receive a dense neurotensinergic innervation, such as the olfactory bulb, bed nucleus of the stria terminalis, magnocellular preoptic nucleus, amygdaloid complex, anterodorsal thalamic nucleus, substantia nigra, ventral tegmental area, and several brainstem nuclei. Most conspicuous among the latter were structures implicated in the descending control of nociceptive inputs (e.g., the periaqueductal gray, dorsal raphe, gigantocellular reticular nucleus, pars alpha, lateral paragigantocellular, and raphe magnus), in keeping with the postulated role of NTS2 receptors in the mediation of neurotensin's supraspinal antinociceptive actions. However, the distribution of NTS2‐like immunoreactivity largely exceeded that of neurotensin terminal fields, and some of the highest concentrations of the receptor were found in areas devoid of neurotensinergic inputs such as the cerebral cortex, the hippocampus, and the cerebellum, suggesting that neurotensin may not be the exclusive endogenous ligand for this receptor subtype. J. Comp. Neurol. 461:520–538, 2003. © 2003 Wiley‐Liss, Inc.
Einnischung der seltenen Steppenrasenart Astragalus exscapus L. (Stengelloser Tragant) im Kyffhäusergebirge (Thüringen, Deutschland)
Authors: Becker T. , Voß N.
Published: May 2003

Die Einnischung der seltenen Steppenrasenart Astragalus exscapus L. im Kyffhäusergebirge wurde untersucht. Astragalus exscapus kommt hier in mehreren Assoziationen der Ordnung Festucetalia valesiacae sowie in Xerobromion‐Beständen vor. Die Art besiedelt damit eine weite Spanne verschiedener Xerothermrasen, die von extrem trockenen Felsfluren bis hin zu mesophilen Halbtrockenrasen reicht. Lediglich in einer Felsflur auf saurem Substrat wurde A. exscapus nicht festgestellt. A. exscapus erreicht in den Felsfluren deutlich geringere Stetigkeit als in den Halbtrockenrasen. Lineare Regressionen zeigen, dass die Stetigkeit von A. exscapus mit zunehmend mesotrophen Standortbedingungen eng korreliert. Andere Standortparameter erbrachten keinen Zusammenhang mit der Stetigkeit der Art. Die Untersuchungen zeigen, dass die Seltenheit von A. exscapus innerhalb der Xerothermrasen des Kyffhäusers nicht durch eine enge standörtliche Amplitude begründet ist. In Verbindung mit einer geringen Ausbreitungskraft der Art schließen wir, dass vegetationsgeschichtliche Gründe für die punktuelle Verbreitung der Art verantwortlich sind. A. exscapus hat die postglaziale Bewaldungsphase nur an wenigen Standorten überdauert, die aufgrund von Trockenheit keinen geschlossenen Waldwuchs zuließen. Seit Beginn der anthropogenen Landnutzung und der damit verbundenen Ausweitung der Xerothermrasen konnte sich die Art wegen ihrer geringen Ausbreitungskraft kaum wieder ausbreiten. Neugründungen und Wiederansiedlungen von Populationen von A. exscapus als Managementmaßnahme sind vermutlich in vielen Xerothermrasen des Mitteldeutschen Trockengebietes möglich.
Neue Untersuchungen an GeinitziaEndl. 1847 aus den Aachener Schichten von Belgien und Deutschland (Oberes Santon, Oberkreide)
Authors: Kunzmann L. , Knoll H. , Gaipl R.
Published: May 2003

Aus den Aachener Schichten (Oberes Santon, Oberkreide) von Belgien und Deutschland werden fertile und sterile Organe von zwei Geinitzia‐Arten beschrieben. Für die als Carpolithes abietinus Schlotheim 1820 (nom. inval.) seit langem bekannten Fossilreste wird die neue Art Geinitzia schlotheimii Kunzmann, Knoll & Gaipl sp. nova aufgestellt. Mit Geinitzia formosa Heer 1871 kommt eine weitere, aus dem Santon Mitteleuropas bekannte Art vor. Das neue Fossilmaterial unterstützt die von Kunzmann (1999) vorgelegte Auffassung über die Koniferengattung Geinitzia Endl. 1847.
Rhodomyrtophyllum reticulosum (Rossm.) Knobloch & Z. Kvaček – ein bedeutendes eozänes Florenelement im Tertiär Mitteleuropas
Authors: Glinka U. , Walther H.
Published: May 2003

Nach kritischer Überprüfung blattepidermaler und blattmorphologischer Merkmalskomplexe an Blättern und Blattresten von Rhodomyrtophyllum Rüffle & Jähnichen aus dem Weißelster‐Becken und seiner Randgebiete in Mitteldeutschland (Raum Halle–Leipzig–Borna–Altenburg–Zeitz–Zwickau und Ostthüringen) wird nachgewiesen, dass es sich bei den Blattresten um Vertreter einer einzigen Art handelt. Die Untersuchungen stützen sich auf 465 Fossilien aus meist kohlig‐ oder tonig‐schluffiger Facies. In einer erweiterten Diagnose wird neben Grundformen mit typischen Charakteristiken die morphologische und blattanatomische Variationsbreite angeführt, die in den natürlichen Grenzen einer Species liegt. Untersuchungen an Blättern weiterer Fundorte in Europa kommen zum gleichen Ergebnis. An Arten von 21 Gattungen rezenter Myrtaceae erfolgen detaillierte Untersuchungen der Blattmorphologie und vor allem der Epidermisstruktur, die markante Ähnlichkeiten zur fossilen Sippe zeigen, was besonders bei Arten der Gattungen Syzygium Gaertn. und Eugenia L. erkennbar ist.
Development of the anther in Nepenthes khasianaHook.f. (Nepenthaceae), an endemic and endangered insectivorous plant of North East India
Authors: Venugopal N. , Rashi Devi N.
Published: May 2003

Nepenthes khasiana Hook.f. is a dioecious insectivorous (carnivorous) plant. The anthers were observed with the SEM. The filaments are connate to form an androphore; the anther heads are sessile in the bud, but as the flower opens the androphore elongates and the bisporangiate anthers are held above the tepals. The archesporial initials comprise of uniseriate rows of cells, the anther wall consists of a very thick endothecium and thin epidermis and the tapetum has a dual in origin, of secretory type. Cytokinesis of microspore mother cell is simultaneous type within a distinct callose wall even after tetrads are formed. Pollen grains are dispersed in tetrads with a sparsely echinate sculpture.
Die Gesellschaften der Bidentetea tripartitae Tx. et al. ex von Rochow 1951 in Mecklenburg‐Vorpommern mit Anmerkungen zur Synsystematik und Nomenklatur der Klasse
Authors: Kiesslich M. , Dengler J. , Berg C.
Published: May 2003

Die Klasse Bidentetea tripartitae ist in Mecklenburg‐Vorpommern mit zwei Verbänden und insgesamt acht Assoziationen vertreten, die durch Vegetationsaufnahmen belegt und floristisch‐ökologisch charakterisiert werden. Der Zentralverband Bidention tripartitae mit dem Polygonetum hydropiperis, dem Corrigiolo litoralis‐Bidentetum radiatae, dem Rumici maritimi‐Ranunculetum scelerati, dem Alopecuretum aequalis und dem Bidentetum cernuae kommt meist in stehenden Gewässern wie wasserführenden Ackerhohlformen, Fisch‐ oder Absetzteichen vor. Das durch zahlreiche Verbandskennarten charakterisierte Chenopodion rubri mit den Assoziationen Chenopodietum rubri, Xanthio albini‐Chenopodietum rubri und Chenopodio polyspermi‐Corrigioletum litoralis ist dagegen weitgehend auf das Elbufer beschränkt; nur seine erste Assoziation tritt (fragmentarisch) auch in anderen Regionen auf.

Der Abgleich mit der vegetationskundlichen Datenbank des Landes (Berg et al. 2001b) zeigt, dass manche in der Literatur als Kennarten der Bidentetea geführte Arten wie Bidens tripartita oder Persicaria hydropiper das Kennartkriterium regional nicht erfüllen, während andererseits Oenanthe aquatica im Gebiet als Klassencharakterart gelten kann. Die Syntaxonomie der Gesellschaften wird auf der Basis des Klassifikationsverfahrens von Dengler & Berg (2002) und vor dem Hintergrund eines umfassenden Literaturvergleichs diskutiert. Für alle behandelten Syntaxa sind die gültigen Namen nach ICPN sowie die wichtigsten Synonyme angeführt, gegebenenfalls mit Angabe der Gründe für deren Invalidität oder Illegitimität. Nomenklatorische Probleme werden erforderlichenfalls erörtert. Für sieben Syntaxa, die bislang nicht typisiert waren, werden nomenklatorische Typen publiziert; ferner vier Namen dem CNC als Nomina ambigua zur Verwerfung vorgeschlagen. Ergänzend wird auf weitere, möglicherweise Assoziationsrang genießende, im Untersuchungsgebiet aber fehlende Syntaxa der Klasse hingewiesen.

Bei den Artenspektren (soziologische Gruppen, Lebensformen, Strategietypen) unterscheiden sich die beiden Verbände deutlich. So ist der Anteil der Therophyten im Chenopodion rubri, jener der Hydrophyten dagegen im Bidention tripartitae deutlich höher. Abschließend wird die Phytodiversität, die Bestandsentwicklung im Zuge von Landnutzungsänderungen und die Naturschutzrelevanz der Bidentetea‐Gesellschaften diskutiert.
Heat transfer performance of a flexible looped heat pipe using R134a as a working fluid: Proposal for a method to predict the maximum heat transfer rate of FLHP
Authors: Kobayashi Takashi , Ogushi Tetsurou , Haga Seiji , Ozaki Eiichi , Fujii Masao
Published: May 2003

This paper presents the heat transfer performance of a Flexible Looped Heat Pipe (FLHP) using R134a as a working fluid. In our evaluation system, an evaporator and a condenser are connected by long flexible tubes with a diameter of 3 mm, and the total piping length of this looped heat pipe system is approximately 7500 mm. We selected porous Teflon with an effective pore diameter of 2rcw = 1.2 µm to overcome high gravitational heads. Elevation of the evaporator above the condenser ΔH = He − Hc) was changed in three conditions [$\def\circle#1{{\ooalign{\hfil\raise.07ex\hbox{#1}\hfil\crcr\mathhexbox20D}}} \circle{1}$ Top heat mode (ΔH = +1 m), $\def\circle#1{{\ooalign{\hfil\raise.07ex\hbox{#1}\hfil\crcr\mathhexbox20D}}} \circle{2}$ Horizontal mode (ΔH = 0), $\def\circle#1{{\ooalign{\hfil\raise.07ex\hbox{#1}\hfil\crcr\mathhexbox20D}}} \circle{3}$ Bottom heat mode (ΔH = −1 m)] considering the terrestrial application and the influence of gravity on the FLHP performance was investigated. FLHP provided high thermal transport capacities over long distances through small cross‐sectional flexible tubes compared with conventional heat pipes. We also proposed an analysis method to predict the maximum heat transfer rate of FLHP. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(4): 306–318, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10093
A numerical study of natural convection in a vertical cylinder bundle
Authors: Isahai Yuji , Hattori Naozo
Published: May 2003

Natural convection in a bundle of vertical cylinders, arranged in equilateral triangular spacing, has been investigated numerically using a boundary‐fitted coordinate system. Numerical calculations for center‐to‐center distance between cylinders S/D = 1.1 to 1.9, 3.0, 4.0, and 7.0 were made of natural convection of air at modified Grashof numbers Gr* from 10 to 108. Local Nusselt number Nu for uniform wall heat flux indicates the same value at the axial locations except for the thermal entrance region. The region for respective cylinder spacing is noted to diminish with decreasing Grashof number. Numerical values of local Nusselt number Nui are in relatively good agreement with those obtained from the experiment for air. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(4): 330–341, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10095
Enhancement of heat transfer in a turbulent channel flow with insertion of a flat body
Authors: Sano Masatoshi
Published: May 2003

Experiments have been performed for turbulent channel flow obstructed with a flat body. The local heat transfer coefficient and the wall static pressure were measured on two kinds of flat bodies for which the trailing edge shape differed. The length of the body, the thickness of the body, and the distance between the wall and the body were changed in several steps. The total performance between heat transfer and pressure drop was estimated under conditions of equal pumping power. The total performance hardly changed, even if the trailing edge shape and length of the bodies were different. The averaged heat transfer coefficient increased with increasing thickness of the bodies. However, as the friction factor increased, the performance became worse. When a comparatively thin body was installed near the heating surface, good performance was obtained. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(4): 354–366, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10100
Heat and mass transfer in a reforming catalyst bed: Analytical prediction of distributions in the catalyst bed
Authors: Usami Yutaka , Fukusako Shoichiro , Yamada Masahiko
Published: May 2003

Heat and mass transfer characteristics within a reforming catalyst bed have been analytically investigated. A numerical analysis was carried out in a two‐dimensional steady‐state model of a reforming catalyst bed. The reforming tube was filled with catalyst and the tube wall was uniformly heated; a mixture of steam and methane was reformed through the catalyst bed. The predicted distributions of temperature, formed gas composition, methane conversion rate, and heat transfer coefficient in the catalyst bed are in good agreement with the experimental data. The effects of space velocity, steam carbon molar ratio, and wall temperature on the heat transfer coefficient were analytically presented. From temperature and composition distributions simulated by the two‐dimensional analysis, the effects of the above‐mentioned factors and diffusion on both heat and mass transport phenomena were qualitatively predicted. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(4): 367–380, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10101
Riparian Trees and Flow Paths between the Hyporheic Zone and Groundwater in the Oberer Seebach, Austria
Authors: Wagner Franz Helmut , Bretschko Gernot
Published: May 2003

We investigated lateral subsurface water exchange in a 2nd order mountain stream with a piezometer method. At both banks the stream hyporheic zone lost water to the riparian groundwater zone. Independently, the hydraulic heads at three sites in the streambed and in the riparian zone exhibited periodic, diurnal fluctuations. We attributed them to water consumption by the riparian trees, as solar radiation explained part of this additional variation.

Our results demonstrate that subsurface water exchanges take place between the hyporheic zone and lateral riparian groundwater in spatially defined small‐scale flow paths. These small‐scale interactions occur within the context of large‐scale patterns of loss and gain of channel water.
Light‐Trapping of Caddisflies at the Thaya (Lower Austria), a River Influenced by Pulsating Hypolimnetic Water Release
Authors: Waringer Johann A.
Published: May 2003

Adult Trichoptera were caught from September 1999 to September 2000 at the Thaya River at Hardegg, Lower Austria, using a Jermy‐type light trap. From a total of 11,711 specimens caught, the most abundant species were Psychomyia pusilla (Fabricius), Lepidostoma hirtum (Fabricius), Lasiocephala basalis (Kolenati), Agapetus ochripes Curtis and Sericostoma flavicorne Schneider. In nine out of the eleven most abundant species the sex ratios significantly differed from 1:1, with an excess of females. Of the meteorological parameters tested, only the effect of air temperature was significant. An upstream shift of faunal zonation patterns from epipotamon to meta‐ and hyporhithron could be detected at the station which is influenced by hypolimnetic water release.
Influence of Environmental Heterogeneity on the Structure of Testate Amoebae (Protozoa, Rhizopoda) Assemblages in the Plankton of the Upper Paraná River Floodplain, Brazil
Authors: Velho Luiz Felipe Machado , Lansac‐Tôha Fábio Amodêo , Bini Luis Mauricio
Published: May 2003

In freshwater environments, testate amoebae are usually found associated with macrophytes and sediments and many studies have suggested that their occurrence in plankton samples is accidental. This implies that predictable patterns detected in planktonic assemblages should not be observed in testate amoebae assemblages. This hypothesis was tested in this study. Plankton samples were collected from different environments in the Upper Paraná River floodplain. Results show that patterns in species composition and abundance of testate amoebae are predictable, and that dominant species tend to present characteristic shell morphology in hydrologically different environments. We suggest that testate amoebae must be routinely included in plankton ecology studies, at least in floodplain environments.
Effect of Campsurus notatus on NH+4, DOC Fluxes, O2 Uptake and Bacterioplankton Production in Experimental Microcosms with Sediment‐Water Interface of an Amazonian Lake Impacted by Bauxite Tailings
Authors: Leal João José Fonseca , de Assis Esteves Francisco , Farjalla Vinicius Fortes , Enrich‐Prast Alex
Published: May 2003

The aim of this study was to evaluate the influence of Campusurus notatus Eaton 1868 (Ephemeroptera: Polimitarciydae) and the impact of bauxite tailings on ammonium (NH4+) and dissolved organic carbon (DOC) fluxes, oxygen uptake and bacterioplankton production in the sediment‐water interface of Lake Batata, a shallow Amazonian floodplain lake. Mesocosms were constructed from natural and impacted areas of Lake Batata, to reproduce the sediment‐water interface. The cores were incubated with 0 to 2,388 ind m–2 of Campsurus notatus nymphs, and the changes in NH4+, DOC, O2 concentration and bacterioplankton production in the overlying water column were measured. Ammonium efflux (F = 9.8, p < 0.05, multiple regression) and oxygen uptake (F = 11.8, p < 0.05) showed a significant correlation with the density of C. notatus in the cores with natural sediment. No differences on DOC release were observed in cores with natural or impacted sediment. In the cores incubated with natural sediment and nymphs of C. notatus, a significant increase (Two‐way ANOVA, p < 0.05) in bacterial production (0.44 μg C l–1 h–1) was observed after 3 hours of incubation. In cores incubated with sediment impacted by bauxite tailings, there was no difference in bacterial production with and without C. notatus. We conclude that C. notatus is an important bioturbator in Lake Batata, increasing the turnover rate of nitrogen (NH4+) at the sediment‐water interface and bacterial production in cores incubated with natural sediment. It is also clear that bauxite tailings reduce the nutrients turnover rates in impacted regions of Lake Batata and influence bacterial production.
The Ratios of Carbon, Nitrogen, and Phosphorus in a Wetland Coastal Ecosystem of Southern India
Authors: Mathews Lizen , Chandramohanakumar N.
Published: May 2003

The fertility of the coastal and estuarine waters is of great concern because of its influence on the productivity of these waters. Seasonal variations in the distribution of organic carbon, total nitrogen and total phosphorus in the sediments of Kuttanad Waters, a part of the tropical Cochin Estuary on the south west coast of India, are examined to identify the contribution of sediments to the fertility of the aquatic systems. The adjoining region has considerable agricultural activity. The fresh water zones had higher quantities of silt and clay whereas the estuarine zone was more sandy. Organic carbon, total phosphorus and total nitrogen were higher in the fresh water zones and lower in the estuarine zones. Total phosphorus and organic carbon showed the lowest values during monsoon periods. No significant trends were observed in the seasonal distributions of total nitrogen.

Ratios of C/N, C/P and N/P, and the phosphorus and nitrogen content indicate significant modification in the character of the organic matter. Substantial amounts of the organic matter can contribute to reducing conditions and modify diagenetic processes.
Thermocyclops dumonti sp. n. (Crustacea, Copepoda), from a Temporary Waterbody in China
Authors: Baribwegure Deo , Mirabdullayev Iskandar M.
Published: May 2003

Six species of the genus Thermocyclops have hitherto been known from Chinese freshwaters. A new species is here recorded from a sample collected from an eutrophic pool in central China. It is described and compared using classical morphology and mapping of its pore signature. Thermocyclops dumonti differs from T. kawamurai by absence of ornamentation on prominences of intercoxal plates of P1‐P3, by relative length of apical spines of Enp3P4 and caudal ramus. It differs from T. dybowskii by ornamentation of P4 intercoxal plate, relative length of Enp3P4 and caudal ramus, by shape of Tmi. As in other species of Thermocyclops, the perforations are bilaterally symmetrical and, species‐specific patterns occur on the cephalosome, metasome, and urosome. Conserved patterns are found elsewhere on the rostrum, cephalosome, metasome, and furcal branches. Based on pore pattern, Thermocyclops dumonti is separated from two close relatives, T. schmeili and T. dybowskii.
A Model to Predict How Individual Factors Influence Secchi Depth Variations among and within Lakes
Authors: Håkanson Lars , Boulion Viktor V.
Published: May 2003

This work presents a model to predict lake Secchi depth. It has been developed as a part of a comprehensive ecosystem model, LakeWeb. The Secchi depth model is based on a modelling technique using dimensionless moderators. It gives, e.g., weekly variations and accounts for how various factors influence Secchi depth individually in spite of the fact that many of them are interrelated in a complex manner. The model has been tested over a wide range of lakes. It gives predictions that agree well with empirical reference regressions, and also expected and requested divergences when the regressions do not provide sufficient resolution. The model is driven by the following data which are easily accessed from standard monitoring programs or maps: Total phosphorus, colour, pH, mean depth and lake area reflecting the three main processes influencing variations of Secchi depth within and among lakes, allochthonous inputs, autochthonous production and resuspension.
Functional groups on polystyrene model nanoparticles: Influence on protein adsorption
Authors: Gessner Andrea , Lieske Antje , Paulke Bernd‐R. , Müller Rainer H.
Published: May 2003

The surface characteristics of intravenously administered particulate drug carriers decisively influence the protein adsorption that is regarded as a key factor for the in vivo fate of the carriers. Latex nanoparticles were synthesized to study the influence of different basic and acidic functional groups on particulate surfaces on the protein adsorption from human serum. The protein mass adsorbed to the particles was assessed by BCA proteinassay, the protein adsorption patterns were analyzed by two‐dimensional electrophoresis. Considerable differences in the protein adsorption with regard to preferential adsorbed proteins were detectable for the different functional groups. Possible correlations between the surface characteristics and the protein adsorption are shown and discussed. The knowledge concerning the interactions of proteins and nanoparticles can be used for a rational development of particulate drug carriers and can also be useful for an optimized design of medical devices, e.g., hemodialysis membranes or implants. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 65A: 319–326, 2003