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81.
Formation of poly(3-hydroxyalkanoates) by phototrophic and chemolithotrophic bacteria 总被引:6,自引:0,他引:6
Matthias Liebergesell Eilert Hustede Arnulf Timm Alexander Steinbüchel R. Clinton Fuller Robert W. Lenz Hans G. Schlegel 《Archives of microbiology》1991,155(5):415-421
The formation of poly(3-hydroxyalkanoic acid), PHA, by various strains of chemolithotrophic and phototrophic bacteria has
been examined. Chemolithotrophic bacteria were grown aerobically under nitrogen-limiting conditions on various aliphatic organic
acids. Phototrophic bacteria were grown anaerobically in the light on a nitrogen-rich medium and were subsequently transferred
to a nitrogen-free medium containing acetate, propionate, valerate, heptanoate or octanoate as carbon source. All 41 strains
investigated in this study were able to synthesize and accumulate PHA. All 11 strains of chemolithotrophic bacteria and all
15 strains belonging to the non-sulfur purple bacteria synthesized a polymer, which contained 3-hydroxy-valerate (3HV) beside
3-hydroxybutyrate (3HB), if the cells were cultivated in the presence of propionate, valerate or heptanoate. Many non-sulfur
purple bacteria synthesized copolyesters of 3HB and 3HV even with acetate as carbon source. In contrast, most sulfur purple
bacteria did not incorporate 3HV at all. Among 15 strains tested, only Chromatium vinosum strain 1611, C. purpuratum strain BN5500 and Lamprocystis roseopersicina strain 3112 were able to synthesize polyesters containing 3HV with propionate, valerate or heptanoate as carbon source. 相似文献
82.
The sulfur oxygenase reductase (SOR) is the initial enzyme in the aerobic sulfur metabolism of the thermoacidophilic and chemolithoautotrophic crenarchaeote Acidianus ambivalens. Single colorless polyhedral crystals were obtained under two crystallization conditions from SOR preparations heterologously overproduced in Escherichia coli. They belonged to space-group I4 and diffraction data were collected up to 1.7 A resolution. Their Patterson symmetry shows additional 4-, 3- and 2-fold non-crystallographic symmetry rotation axes, characteristic of the point group 432. Taking into account the molecular mass of SOR, the crystal unit cell volume, the non-crystallographic symmetry operators and previous electron microscopy studies of the SOR, it was deduced that the quaternary structure of the functionally active enzyme is an icosatetramer with 871 kDa molecular mass. 相似文献
83.
52 entries including landraces, old cultivars and wild accessions of B. oleracea and closely related Brassica species were screened for resistance against downy mildew and clubroot. Several accessions resistant to downy mildew and a few to clubroot were found. Genetic inheritance of the resistance in downy mildew was investigated by screening F1 and BC1F1 offspring from three resistant landrace accessions crossed with both a resistant and a susceptible father. The seedling resistance against downy mildew was found to be inherited recessively. This is a bit surprising as earlier papers mostly report of inheritance controlled by a single dominant gene. Previous screenings of B. oleracea resistance against downy mildew at the cotyledon stage have been done with P. parasitica isolated from B. oleracea as the original host plant. The recessive nature of the cotyledon resistance found in this screening might be due to the fact that the P. parasitica isolate was collected from B. napus fields. The clubroot seedling resistance was found to be controlled by recessive inheritance after screening the F1 offspring, this in agreement with earlier results/reports. 相似文献
84.
Lessons to be learned from primary renal cell carcinomas: novel tumor antigens and HLA ligands for immunotherapy 总被引:2,自引:0,他引:2
Krüger T Schoor O Lemmel C Kraemer B Reichle C Dengjel J Weinschenk T Müller M Hennenlotter J Stenzl A Rammensee HG Stevanović S 《Cancer immunology, immunotherapy : CII》2005,54(9):826-836
The lack of sufficient well-defined tumor-associated antigens is still a drawback on the way to a cytotoxic T-lymphocyte-based immunotherapy of renal cell carcinoma (RCC). We are trying to define a larger number of such targets by a combined approach involving HLA ligand characterization by mass spectrometry and gene expression profiling by oligonucleotide microarrays. Here, we present the results of a large-scale analysis of 13 RCC specimens. We were able to identify more than 700 peptides, mostly from self-proteins without any evident tumor association. However, some HLA ligands derived from previously known tumor antigens in RCC. In addition, gene expression profiling of tumors and a set of healthy tissues revealed novel candidate RCC-associated antigens. For several of them, we were able to characterize HLA ligands after extraction from the tumor tissue. Apart from universal RCC antigens, some proteins seem to be appropriate candidates in individual patients only. This underlines the advantage of a personalized therapeutic approach. Further analyses will contribute additional HLA ligands to this repertoire of universal as well as patient-individual tumor antigens.Tobias Krüger and Oliver Schoor contributed equally to this work. 相似文献
85.
Cell-free extracts of facultatively anaerobic, sulfur-dependent archaebacteria Acidianus infernus (DSM 3191), and Acidianus brierleyi (DSM 1651) were examine by two-dimensional gel electrophoresis. 56 out of 250 protein spots were induced in anaerobically grown cells of A. infernus compared with 57 out of 251 in aerobically grown cells. In aerobically grown cells of A. brierleyi 62 out of 160 spots were induced, compared with 84 out of 182 in anaerobically grown cells. Changes in the protein patterns of both species were not comparable. 相似文献
86.
P. Boysen Jensen 《Planta》1928,6(3):456-472
Ohne ZusammenfassungMit 7 Textabbildungen. 相似文献
87.
Doris Stelzer Susanne Schneider Arnulf Melzer 《International Review of Hydrobiology》2005,90(2):223-237
The European Water Framework Directive requires ecological status classification and monitoring of surface and ground water bodies using biological indicators. To fulfill the demands of the Directive, a macrophyte‐based assessment system was developed for application on four lake site types in Germany. Biological lake site types were established using differences in characteristic macrophyte communities, reflecting ecoregion, Ca2+ content, mixis and morphology. Ecological status classification of lake sites is based on macrophyte abundance along 275 transects in 95 natural German lakes and the calculation of a reference index value, in some cases supplemented by submerged vegetation data. The reference index quantifies the deviation of species composition and abundance from reference conditions and classifies sites to one of the five ecological quality classes specified in the Directive. Based on an example of Lake Chiemsee, Germany, the possibilities for a wholelake assessment are discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
88.
White sturgeon, Acipenser transmontanus (Richardson), are at risk of entrainment from dredging, with young-of-the-year fish at greatest risk. To evaluate this entrainment risk, swimming performance trials were conducted in a laboratory swim tunnel with hatchery-reared juvenile white sturgeon with varying experience levels including: naïve (only tested once), tested (re-tested after being kept in no flow) and trained (re-tested after kept in flow for nearly three weeks). Individuals of various sizes (80–100 mm TL) and all experience levels were strongly rheotactic (> 80%), but endurance was highly variable among fish. Small juveniles [< 82 mm total length (TL)] had lower escape speeds (< 40 cm s−1 ) than medium (82–92 mm TL) and large (> 93 mm TL) naïve fish (42–45 cm s−1 ), all of which had lower escape speeds than trained fish (72 cm s−1 ). Behavior was also highly variable among fish. Overall, benthic station-holding behaviors were least frequent in small fish, intermediate in medium and large fish, and most frequent in trained large fish. Probability of entrainment of juvenile white sturgeon can be reduced by maintaining dredge head flow fields at less than 45 cm s−1 for wild-spawned fish or by rearing hatchery fish to > 93 mm TL and exposing the fish to moderate flow velocities (10–12 cm s−1 ) prior to their release. 相似文献
89.
Sandra Krull Julia Dörries Björn Boysen Sonja Reidenbach Lars Magnius Helene Norder Johan Thyberg Volker C Cordes 《The EMBO journal》2010,29(10):1659-1673
Amassments of heterochromatin in somatic cells occur in close contact with the nuclear envelope (NE) but are gapped by channel‐ and cone‐like zones that appear largely free of heterochromatin and associated with the nuclear pore complexes (NPCs). To identify proteins involved in forming such heterochromatin exclusion zones (HEZs), we used a cell culture model in which chromatin condensation induced by poliovirus (PV) infection revealed HEZs resembling those in normal tissue cells. HEZ occurrence depended on the NPC‐associated protein Tpr and its large coiled coil‐forming domain. RNAi‐mediated loss of Tpr allowed condensing chromatin to occur all along the NE's nuclear surface, resulting in HEZs no longer being established and NPCs covered by heterochromatin. These results assign a central function to Tpr as a determinant of perinuclear organization, with a direct role in forming a morphologically distinct nuclear sub‐compartment and delimiting heterochromatin distribution. 相似文献
90.
Across a range of vertebrate species, it is known that there is a negative association between maximum lifespan and mitochondrial hydrogen peroxide production. In this report, we investigate the underlying biochemical basis of the low hydrogen peroxide production rate of heart mitochondria from a long-lived species (pigeon) compared with a short-lived species with similar body mass (rat). The difference in hydrogen peroxide efflux rate was not explained by differences in either superoxide dismutase activity or hydrogen peroxide removal capacity. During succinate oxidation, the difference in hydrogen peroxide production rate between the species was localized to the ΔpH-sensitive superoxide producing site within complex I. Mitochondrial ΔpH was significantly lower in pigeon mitochondria compared with rat, but this difference in ΔpH was not great enough to explain the lower hydrogen peroxide production rate. As judged by mitochondrial flavin mononucleotide content and blue native polyacrylamide gel electrophoresis, pigeon mitochondria contained less complex I than rat mitochondria. Recalculation revealed that the rates of hydrogen peroxide production per molecule of complex I were the same in rat and pigeon. We conclude that mitochondria from the long-lived pigeon display low rates of hydrogen peroxide production because they have low levels of complex I. 相似文献