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61.
We investigated brain development in the horseshoe crab Limulus polyphemus and several other arthropods via immunocytochemical methods, i.e. antibody stainings against acetylated alpha-tubulin and synapsin. According to the traditional view, the first appendage-bearing segment in chelicerates (the chelicerae) is not homologous to the first appendage-bearing segment of mandibulates (first antenna, deutocerebrum) but to the segment of the second antenna (tritocerebrum) or the intercalary segment in hexapods and myriapods. Accordingly, the segment of the deutocerebrum in chelicerates would be completely reduced. The main arguments for this view are: (1) the postoral origin of the cheliceral ganglion, (2) a poststomodaeal commissure, and (3) a connection of the cheliceral ganglion to the stomatogastric system. Our data show that these arguments are not convincing. During the development of horseshoe crabs there is no evidence for a former additional segment in front of the chelicerae. Instead, comparison of the brain structure (neuropil ring) between chelicerates, crustaceans and insects shows remarkable similarities. Furthermore, the cheliceral commissure in horseshoe crabs runs mainly praestomodaeal, which would be unique for a tritocerebral commissure. An unbiased view of the developing nervous system in the "head" of chelicerates, crustaceans and insects leads to a homologisation of the cheliceral segment and that of the (first) antenna (= deutocerebrum) of mandibulates that is also congruous to the interpretation of the Hox gene expression patterns. Thus, our data provide morphological evidence for the existence of a chelicerate deutocerebrum. 相似文献
62.
Cell-specific expression of the mercury-insensitive plasma-membrane aquaporin NtAQP1 from Nicotiana tabacum 总被引:9,自引:0,他引:9
The aquaporin NtAQP1 from Nicotiana tabacum L. is insensitive to heavy-metal ions. In addition to water, the transport of urea or glycerol is facilitated by this plasma-membrane-located
water channel. Northern hybridization and whole-mount in situ hybridization revealed a high steady-state level of NtAQP1-RNA
in roots, a decreased content in shoots and a low content in leaves. By immunolocalization with an antibody targeted to the
N-terminus of the aquaporin, the localization of NtAQP1-protein at sites of expected high water transport rates from and to
the apoplast or symplast could be demonstrated. The specific pattern of NtAQP1 distribution in petioles strongly indicates
a transcellular movement of water.
Received: 12 August 1999 / Accepted: 27 December 1999 相似文献
63.
Intracellular pathways and degradation of endosomal contents in basal epithelial cells of freshwater sponges (Porifera, Spongillidae) 总被引:1,自引:1,他引:0
The digestive system expressed by basal epithelial cells of the freshwater sponges Spongilla lacustris and Ephydatia muelleri is mainly represented by a population of 30–50 preexisting lysosomes located in the close vicinity of the central nucleus.
The strongly acidic vacuoles (pH 4–4.5) vary in size between 1 and 3 μm, and contain a set of different lysosomal enzymes.
Immunocytochemical studies succeeded in the detection of β-hexosaminidase, cathepsin D, acid phosphatase, and α-glucosidase.
Endosomes resulting from fluid-phase macropinocytosis, receptor-mediated endocytosis, or phagocytotic activity deliver their
exogenous contents to the preexisting lysosomes for enzymatic degradation. Macropinosomes and phagosomes follow a rather reduced
intracellular pathway by immediate fusion with the lysosomal compartment, whereas substances conveyed by coated vesicles pass
through two additional vacuolar stages, namely early and late endosomes. Early endosomes serve as sorting organelles and segregate
various constituents of complex ligands (BSA-AU6, BSA-AU12) by size into individual late endosomes, which then coalesce with preexisting lysosomes. As a whole, the intracellular pathways
and hydrolytic processing of endosomal and phagosomal contents in freshwater sponge cells share certain similarities with
the respective mechanisms in cells of higher eukaryotes.
Accepted: 7 October 1997 相似文献
64.
S. Thomar Ulrike Dumke-Lehmann Beate Diettrich M. Luckner 《Plant biology (Stuttgart, Germany)》1998,111(1):22-27
Digitalis lanata was transformed by agrobacteria-mediated gene transfer with a chimeric reporter gene encoding for β-glucuronidase (CUS) from Escherichia coll under the control of the plastocyanin 3 (Pc3) promoter from Spinada oleracea (Pc3::uidA fusion gene). Transformed cell lines were regenerated to plants via somatic embryos. CUS activity was determined fluorometrically and histochemically. The Pc3::uidA fusion gene was expressed in the late globular and bipolar stages of somatic embryos. Expression started in globular embryos (stage-1-globules) in that part of the parenchymatic tissue which later on formed the cotyledons. No GUS activity was detectable in the parenchymatic tissue forming the root pole, in cells of the developing procambium or in epidermal cells. These tissues were free of GUS activity also in bipolar embryos. The parenchymatic cells of the cotyledons and the primary cortex of the hypocotyl of germinating embryos showed GUS activity, in contrast to the epidermal cells and the cells of the central cylinder. 相似文献
65.
In a seminatural manipulation experiment with artificial irrigation we followed throughfall and forest floor solution chemistry collected underneath aphid infested and uninfested Norway spruce. Solutions underneath infested trees showed significantly higher concentrations of dissolved organic carbon (DOC) but lower concentrations of dissolved organic nitrogen (DON), NO3 -N, and NH4 -N in throughfall solutions and of NH4 -N in forest floor solutions. Average concentrations were 40.5% (DON), 27.5% (NO3 -N), and 46.2% lower (NH4 -N) underneath infested trees in throughfall solutions, and 19.5% (DON), 9.4% (NO3 -N), and 42.0% (NH4 -N) lower in forest floor solutions. Differences in throughfall were more pronounced than in forest floor leachates. It is likely that honeydew is fuelling the metabolism of micro-organisms and thus critically affects above and below ground nutrient cycles. We emphasize the importance of linking the biology of herbivores and micro-organisms with geochemical processes. 相似文献
66.
Extraction and long‐term storage of S‐layer proteins and flagella from Lysinibacillus sphaericus NCTC 9602: Building blocks for nanotechnology
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Anja Blüher Kai Ostermann Petra Jäckel Andrè Clemens Beate Katzschner Gerhard Rödel Michael Mertig 《Engineering in Life Science》2015,15(4):410-415
Self‐assembling surface layer (SL) proteins of bacteria have been widely studied, in particular their use as molecularly defined, 2D coatings of technical surfaces. An important prerequisite is the availability of a sufficient amount of protein. However, a detailed and optimized protocol for the complete SL extraction is so far not available. Here, we describe the complete purification and reassembly procedure of an SL protein of Lysinibacillus sphaericus NCTC 9602, starting from the cultivation of cells, the preparation and purification of SL proteins up to the long‐term storage and in vitro self‐assembly of the proteins. All crucial steps of the procedure are assessed by different microscopic techniques, such as light microscopy, atomic force microscopy, and scanning electron microscopy as well as by SDS‐PAGE as a biochemical method. We demonstrate that storage of the protein in the presence of sodium azide or upon lyophilization allows the preservation of the self‐assembly properties for at least 9 years. Additionally, we describe a method allowing the extraction of intact flagella with lengths in the range up to 4 μm. Flagella may have applications in bio‐nanotechnology, for example as templates for metallic nanowires. 相似文献
67.
Sebastian R. Schreglmann Martin Regensburger Edward Rockenstein Eliezer Masliah Wei Xiang Jürgen Winkler Beate Winner 《PloS one》2015,10(5)
Background
Adult neurogenesis mirrors the brain´s endogenous capacity to generate new neurons throughout life. In the subventricular zone/ olfactory bulb system adult neurogenesis is linked to physiological olfactory function and has been shown to be impaired in murine models of neuronal alpha-Synuclein overexpression. We analyzed the degree and temporo-spatial dynamics of adult olfactory bulb neurogenesis in transgenic mice expressing human wild-type alpha-Synuclein (WTS) under the murine Thy1 (mThy1) promoter, a model known to have a particularly high tg expression associated with impaired olfaction.Results
Survival of newly generated neurons (NeuN-positive) in the olfactory bulb was unchanged in mThy1 transgenic animals. Due to decreased dopaminergic differentiation a reduction in new dopaminergic neurons within the olfactory bulb glomerular layer was present. This is in contrast to our previously published data on transgenic animals that express WTS under the control of the human platelet-derived growth factor β (PDGF) promoter, that display a widespread decrease in survival of newly generated neurons in regions of adult neurogenesis, resulting in a much more pronounced neurogenesis deficit. Temporal and quantitative expression analysis using immunofluorescence co-localization analysis and Western blots revealed that in comparison to PDGF transgenic animals, in mThy1 transgenic animals WTS is expressed from later stages of neuronal maturation only but at significantly higher levels both in the olfactory bulb and cortex.Conclusions
The dissociation between higher absolute expression levels of alpha-Synuclein but less severe impact on adult olfactory neurogenesis in mThy1 transgenic mice highlights the importance of temporal expression characteristics of alpha-Synuclein on the maturation of newborn neurons. 相似文献68.
Adalbert Krawczyk Miriam Dirks Maren Kasper Anna Buch Ulf Dittmer Bernd Giebel Lena Wildschütz Martin Busch Andre Goergens Karl E. Schneweis Anna M. Eis-Hübinger Beate Sodeik Arnd Heiligenhaus Michael Roggendorf Dirk Bauer 《PloS one》2015,10(1)
The increasing incidence of acyclovir (ACV) and multidrug-resistant strains in patients with corneal HSV-1 infections leading to Herpetic Stromal Keratitis (HSK) is a major health problem in industrialized countries and often results in blindness. To overcome this obstacle, we have previously developed an HSV-gB-specific monoclonal antibody (mAb 2c) that proved to be highly protective in immunodeficient NOD/SCID-mice towards genital infections. In the present study, we examined the effectivity of mAb 2c in preventing the immunopathological disease HSK in the HSK BALB/c mouse model. Therefore, mice were inoculated with HSV-1 strain KOS on the scarified cornea to induce HSK and subsequently either systemically or topically treated with mAb 2c. Systemic treatment was performed by intravenous administration of mAb 2c 24 h prior to infection (pre-exposure prophylaxis) or 24, 40, and 56 hours after infection (post-exposure immunotherapy). Topical treatment was performed by periodical inoculations (5 times per day) of antibody-containing eye drops as control, starting at 24 h post infection. Systemic antibody treatment markedly reduced viral loads at the site of infection and completely protected mice from developing HSK. The administration of the antiviral antibody prior or post infection was equally effective. Topical treatment had no improving effect on the severity of HSK. In conclusion, our data demonstrate that mAb 2c proved to be an excellent drug for the treatment of corneal HSV-infections and for prevention of HSK and blindness. Moreover, the humanized counterpart (mAb hu2c) was equally effective in protecting mice from HSV-induced HSK when compared to the parental mouse antibody. These results warrant the future development of this antibody as a novel approach for the treatment of corneal HSV-infections in humans. 相似文献
69.
Alexa Orand Arpana Gupta Wendy Shih Angela P. Presson Christian Hammer Beate Niesler Nuwanthi Heendeniya Emeran A. Mayer Lin Chang 《PloS one》2015,10(8)
Background
Genetic and environmental factors contribute to the pathophysiology of irritable bowel syndrome (IBS). In particular, early adverse life events (EALs) and the catecholaminergic system have been implicated.Aims
To investigate whether catecholaminergic SNPs with or without interacting with EALs are associated with: 1) a diagnosis of IBS, 2) IBS symptoms and 3) morphological alterations in brain regions associated with somatosensory, viscerosensory, and interoceptive processes.Methods
In 277 IBS and 382 healthy control subjects (HCs), 11 SNPs in genes of the catecholaminergic signaling pathway were genotyped. A subset (121 IBS, 209 HCs) underwent structural brain imaging (magnetic resonance imaging [MRI]). Logistic and linear regressions evaluated each SNP separately and their interactions with EALs in predicting IBS and GI symptom severity, respectively. General linear models determined grey matter (GM) alterations from the SNPs and EALs that were predictive of IBS.Results
1) Diagnosis: There were no statistically significant associations between the SNPs and IBS status with or without the interaction with EAL after adjusting for multiple comparisons. 2) Symptoms: GI symptom severity was associated with ADRA1D rs1556832 (P = 0.010). 3) Brain morphometry: In IBS, the homozygous genotype of the major ADRA1D allele was associated with GM increases in somatosensory regions (FDR q = 0.022), left precentral gyrus (q = 0.045), and right hippocampus (q = 0.009). In individuals with increasing sexual abuse scores, the ADRAβ2 SNP was associated with GM changes in the left posterior insula (q = 0.004) and left putamen volume (q = 0.029).Conclusion
In IBS, catecholaminergic SNPs are associated with symptom severity and morphological changes in brain regions concerned with sensory processing and modulation and affect regulation. Thus, certain adrenergic receptor genes may facilitate or worsen IBS symptoms. 相似文献70.
Fabian Haertling Beate Mueller Oliver Bilke-Hentsch 《Attention deficit and hyperactivity disorders》2015,7(2):157-164
Long-acting (LA) preparations of methylphenidate allow for once-daily dosing; however, pharmacokinetics may vary and depend on food intake. The objective was to evaluate effectiveness of a two-phase release formulation (Ritalin® LA) under daily practice conditions. This was a prospective, multicenter, observational study in Germany. Eligibility and dosing were determined by the physician based on the drug label. Outcomes included changes over 3 months of treatment in assessments of effect duration, clinical global impression (CGI), and quality of life (ILK). In 101 sites, 262 patients (197 boys, 63 girls, and two unknown) with a mean age of 10.9 years were enrolled; 50 were treated for the first time; 212 switched medication to Ritalin® LA. After 3 months, CGI improved in 59.4 % of patients, and well-being overall was rated as good by 61.0 % of parents and 63.7 % of children. Based on parents’ assessment, the proportion of children suffering from strong disease burden decreased from 40.7 to 15.1 %. In 123 insufficient responders to previous ADHD medications, benefit from Ritalin® LA was above average and effect duration was significantly prolonged as compared to pretreatment. Overall, 28 patients (10.7 %) had treatment-related adverse events with one case being serious; 23 patients (8.8 %) discontinued therapy, 7 (2.7 %) due to poor treatment response; and 212 patients (81 %) continued treatment beyond the study. In line with clinical trial data, Ritalin® LA provides significant benefit also under routine practice conditions. 相似文献