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41.
In this study, we present the first genetic evidence of the phylogenetic position of Tarsius pumilus, the mountain tarsier of Sulawesi, Indonesia. This mysterious primate is the only Eastern tarsier species that occurs exclusively in cloud forests above 1800 m.a.s.l. It exhibits striking morphological peculiarities—most prominently its extremely reduced body size, which led to the common name of ‘pygmy tarsier’. However, our results indicate that T. pumilus is not an aberrant form of a lowland tarsier, but in fact, the most basal of all Sulawesi tarsiers. Applying a Bayesian multi-locus coalescent approach, we dated the divergence between the T. pumilus lineage and the ancestor of all other extant Sulawesi tarsiers to 9.88 Mya. This is as deep as the split between the two other tarsier genera Carlito (Philippine tarsiers) and Cephalopachus (Western tarsiers), and predates further tarsier diversification on Sulawesi by around 7 Myr. The date coincides with the deepening of the marine environment between eastern and western Sulawesi, which likely led to allopatric speciation between T. pumilus or its predecessor in the west and the ancestor of all other Sulawesi tarsiers in the east. As the split preceded the emergence of permanent mountains in western Sulawesi, it is unlikely that the shift to montane habitat has driven the formation of the T. pumilus lineage.  相似文献   
42.
43.
The 3-isopropyl (I), 3-cyclohexyl (II) and 3-phenyl (III) analogs of the new antipsychotic drug butaclamol, which contains a 3-tertiary butyl group, and their respective (+)-enantiomers, but not (-)-enantiomers, caused a dose related elevation of rat striatal homovanillic acid concentration, indicative of an increased dopamine (DA) turnover; droperidol also exhibited this activity. The order of activity of the (+)-enantiomers was (butaclamol) approximately II greater than I greater than III. A decrease in striatal DA was observed with (+)-I and (+)-III at the highest dose used, but not at one-half the dose. Each analog antagonized the DA-induced increase in adenyl cyclase (EC 4.6.1.1) activity of olfactory tubercle homogenates, the order of activity of the racemates (except for II) AND (+)-ENANTIOMERS BEING (BUTACLAMOL) APPROXIMATELY I greater than III greater than II. The (+)-enantiomers of butaclamol and analogs were two to four times more potent than their respective racemates, with (+)-butaclamol and (+)-I displaying activity generally equivalent to fluphenazine. The respective (-)-enantiomers were ineffective indicating a stereochemical specificity for DA-receptor blockade. Such analogs presented should be of value in elucidating dopaminergic mechansims.  相似文献   
44.
Zusammenfassung An der lichtmikroskopischen Struktur des plexus chorioideus ventriculi III von Ateles, Cebus, Macaca und Pan fallen deutliche speziesbedingte Unterschiede auf. Bei Macaca wurde die Ultrastruktur der Plexus chorioidei ventriculi III und IV sowie der Plexus chorioidei der Seitenventrikel verglichen. Kuppenzellen überwiegen im elektronen-mikroskopischen Bild der Plexusepithelien des III. und IV. Ventrikels, während unter den Epithelien der Seitenventrikel flachere Zellen dominieren. Diese strukturellen Besonderheiten könnten auf funktionelle Unterschiede in der Liquorbildung hinweisen. Das Problem der extrachorioidalen Liquorproduktion (Curl and Pollay, 1968; Milhorat u. Mitarb., 1971) wird im Zusammenhang mit den regionalen Unterschieden in der Wandstruktur des Aquaeductus cerebri (Sylvii) diskutiert (Merker, 1970). Im Stroma und im Interstitium aller Plexus chorioidei des Rhesusaffen sind makrophagenartige Wanderzellen zu beobachten, deren Strukturbild dem der Epiplexuszellen gleicht; sie werden als ausgewanderte Monozyten gedeutet. Wahrscheinlich gelangen diese Zellen in den Ventrikel und werden dort zu Epiplexuszellen. Einschlüsse vom Typ der Biondi-Körper wurden in den Plexusepithelien der untersuchten Affen nicht beobachtet; die untersuchten Tiere hatten aber noch kein hohes Lebensalter erreicht.
The fine structure of the choroid plexuses in monkeys
Summary The light microscopic structure of the choroid plexus of the IIIrd ventricle was studied in Ateles, Cebus, Macaca and Pan. These choroid plexuses display distinct species differences. The ultrastructure of the choroid plexuses of the IIIrd, IVth and lateral ventricles was compared in Macaca. Cuboidal cells with dome-like protrusions predominate in the epithelium of the choroid plexuses of the IIIrd and the IVth ventricles, while flattened cells are characteristic of the choroid epithelium of the lateral ventricle. These structural peculiarities may reflect functional differences in the production of the cerebrospinal fluid. The problem of extrachoroidal production of the cerebrospinal fluid (Curl and Pollay, 1968; Milhorat et al., 1971) is discussed in connection with regional differences in the structure of the aqueduct wall (Merker, 1970). Macrophage-like cells which morphologically resemble epiplexus cells and which are very abundant within the connective tissue stroma and also between the epithelial cells of all choroid plexuses of the rhesus monkey, are thought to be monocytes. Probably these cells migrate into the ventricle where they become epiplexus cells. Epithelial inclusions of the type of Biondi bodies were not observed in the simian choroid plexuses. However, the animals investigated were not old.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft (Arbeitskreis Prof. Dr. A. Oksche).  相似文献   
45.

Rapid eye movement (REM) sleep behavior disorder (RBD) and hypnagogic hallucinations are salient symptoms of abnormal and dissociated REM sleep that are frequently associated in serious neurological diseases. RBD is a strong, independent risk factor for hallucinations in narcolepsy (odds ratio: 4.3) and in Parkinson’s disease (odds ratio: 2.7). In Parkinson’s disease, RBD also predicts incident hallucinations and psychosis in prospective cohorts. Status dissociatus (a mixture of hallucinations, RBD, and dissociated sleep-wake states) is observed in patients with Guillain-Barré when hallucinating, but also in Lewy bodies dementia, delirium tremens, fatal familial insomnia, and Morvan’s chorea. This co-occurrence of RBD and visual hallucinations suggests a common, extensive lesion within REM sleep executive systems.

  相似文献   
46.
Bevacizumab treatment can result in tumor shrinkage of progressive vestibular schwannomas in some neurofibromatosis 2 (NF2) patients but its effect on meningiomas has not been defined.To determine the clinical activity of bevacizumab against NF2-related meningiomas, we measured changes in volume of meningiomas in NF2 patients who received bevacizumab for treatment of progressive vestibular schwannomas. A radiographic response was defined as a 20% decrease in tumor size by volumetric MRI analysis. In addition, we determined the expression pattern of growth factors associated with tumor angiogenesis in paraffin-embedded tissues from 26 unrelated meningiomas. A total of 48 meningiomas in 15 NF2 patients were included in this study with a median follow up time of 18 months. A volumetric radiographic response was seen in 29% of the meningiomas (14/48). Tumor shrinkage was not durable: the median duration of response was 3.7 months and the median time to progression was 15 months. There was no significant correlation between pre-treatment growth rate and meningioma response in regression models. Tissue analysis showed no correlation between tumor microvascular density and expression of VEGF pathway components. This data suggests that, in contrast to schwannomas, activation of VEGF pathway is not the primary driver of angiogenesis in meningiomas. Our results suggest that a minority of NF2-associated meningiomas shrink during bevacizumab therapy and that these responses were of short duration. These results are comparable to previous studies of bevacizumab in sporadic meningiomas.  相似文献   
47.
H J Merker  M Pospisil  P Mewes 《Teratology》1975,11(2):199-217
On day 12 of pregnancy Wistar rats were each given a single ip injection of 5, 8, 16, 25, or 50 mg/kg 6-mercaptopurine. The embryos were removed 1, 2, 3, 5, 6, 10, 24, 48, or 72 h after injection or on day 20 and studied by light and electron microscopy. After 25 or 50 mg/kg all embryos showed no mineralization in the lower extremities. By electron microscopy condensation, shrinking, and fragmentation of cells in the limb bud blastema could be seen after 5 h. The fragments were phagocytosed and broken down by neighboring cells or remained in the extracellular space. After 25 or 50 mg/kg the damage was so extensive that the number of undamaged cells and of cells transforming into phagocytes was not sufficient to remove the debris or to compensate for the defect by mitotic activity. Epithelial cells, nerves, and blood vessels, show no morphological signs of damage. The "critical period" was the time cartilage just starts developing, i.e., when the blastema begins to differentiate.  相似文献   
48.
A biochemical, biophysical, and phylogenetic study of the sulfur oxygenase reductase (SOR) from the mesophilic gammaproteobacterium Halothiobacillus neapolitanus (HnSOR) was performed in order to determine the structural and biochemical properties of the enzyme. SOR proteins from 14 predominantly chemolithoautotrophic bacterial and archaeal species are currently available in public databases. Sequence alignment and phylogenetic analysis showed that they form a coherent protein family. The HnSOR purified from Escherichia coli after heterologous gene expression had a temperature range of activity of 10 to 99°C with an optimum at 80°C (42 U/mg protein). Sulfite, thiosulfate, and hydrogen sulfide were formed at various stoichiometries in a range between pH 5.4 and 11 (optimum pH 8.4). Circular dichroism (CD) spectroscopy and dynamic light scattering showed that the HnSOR adopts secondary and quaternary structures similar to those of the 24-subunit enzyme from the hyperthermophile Acidianus ambivalens (AaSOR). The melting point of the HnSOR was ≈20°C lower than that of the AaSOR, when analyzed with CD-monitored thermal unfolding. Homology modeling showed that the secondary structure elements of single subunits are conserved. Subtle changes in the pores of the outer shell and increased flexibility might contribute to activity at low temperature. We concluded that the thermostability was the result of a rigid protein core together with the stabilizing effect of the 24-subunit hollow sphere.  相似文献   
49.
F Bertels  H Merker  C Kost 《PloS one》2012,7(7):e41349
Efficient and inexpensive methods are required for the high-throughput quantification of amino acids in physiological fluids or microbial cell cultures. Here we develop an array of Escherichia coli biosensors to sensitively quantify eleven different amino acids. By using online databases, genes involved in amino acid biosynthesis were identified that - upon deletion - should render the corresponding mutant auxotrophic for one particular amino acid. This rational design strategy suggested genes involved in the biosynthesis of arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, threonine, tryptophan, and tyrosine as potential genetic targets. A detailed phenotypic characterization of the corresponding single-gene deletion mutants indeed confirmed that these strains could neither grow on a minimal medium lacking amino acids nor transform any other proteinogenic amino acid into the focal one. Site-specific integration of the egfp gene into the chromosome of each biosensor decreased the detection limit of the GFP-labeled cells by 30% relative to turbidometric measurements. Finally, using the biosensors to determine the amino acid concentration in the supernatants of two amino acid overproducing E. coli strains (i.e. ΔhisL and ΔtdcC) both turbidometrically and via GFP fluorescence emission and comparing the results to conventional HPLC measurements confirmed the utility of the developed biosensor system. Taken together, our study provides not only a genotypically and phenotypically well-characterized set of publicly available amino acid biosensors, but also demonstrates the feasibility of the rational design strategy used.  相似文献   
50.
The garnet-type phase Li7La3Zr2O12 (LLZO) attracts significant attention as an oxide solid electrolyte to enable safe and robust solid-state batteries (SSBs) with potentially high energy density. However, while significant progress has been made in demonstrating compatibility with Li metal, integrating LLZO into composite cathodes remains a challenge. The current perspective focuses on the critical issues that need to be addressed to achieve the ultimate goal of an all-solid-state LLZO-based battery that delivers safety, durability, and pack-level performance characteristics that are unobtainable with state-of-the-art Li-ion batteries. This perspective complements existing reviews of solid/solid interfaces with more emphasis on understanding numerous homo- and heteroionic interfaces in a pure oxide-based SSB and the various phenomena that accompany the evolution of the chemical, electrochemical, structural, morphological, and mechanical properties of those interfaces during processing and operation. Finally, the insights gained from a comprehensive literature survey of LLZO–cathode interfaces are used to guide efforts for the development of LLZO-based SSBs.  相似文献   
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