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31.
Puccinia graminis subsp. graminicola has caused economically important losses of tall fescue (Festuca arundinacea Schreb.) in North America. This rust infects leaves, culms, and spikelets of the host. Initital symptoms consist of very small, chlorotic flecks, followed by long, narrow lesions. Invasive hyphae were diffuse and filamentous, changing to dense and blocky with the formation of hymenia. Tissues were extensively colonized, including development caryopses. Seedborne infection consisted of mycelium within the embryo and urediniospores carried on both surfaces of the glumes. It is not known whether caryopses that are internally infected can germinate to produce infected individuals, but this could be an important quarantine consideration. Although, at the ultrastructural level, urediniospore development in this fungus is similar to that of other rusts, we detected an additional layer at the interface of the urediniospore and its pedicel. This layer may play a role in the, release of urediniospores from their pedicels. 相似文献
32.
Kamil Deryło Barbara Michalec-Wawiórka Dawid Krokowski Leszek Wawiórka Maria Hatzoglou Marek Tchórzewski 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2018,1865(1):34-47
The ribosomal uL10 protein, formerly known as P0, is an essential element of the ribosomal GTPase-associated center responsible for the interplay with translational factors during various stages of protein synthesis. In eukaryotic cells, uL10 binds two P1/P2 protein heterodimers to form a pentameric P-stalk, described as uL10-(P1-P2)2, which represents the functional form of these proteins on translating ribosomes. Unlike most ribosomal proteins, which are incorporated into pre-ribosomal particles during early steps of ribosome biogenesis in the nucleus, P-stalk proteins are attached to the 60S subunit in the cytoplasm. Although the primary role of the P-stalk is related to the process of translation, other extraribosomal functions of its constituents have been proposed, especially for the uL10 protein; however, the list of its activities beyond the ribosome is still an open question. Here, by the combination of biochemical and advanced fluorescence microscopy techniques, we demonstrate that upon nucleolar stress induction the uL10 protein accumulates in the cytoplasm of mammalian cells as a free, ribosome-unbound protein. Importantly, using a novel approach, FRAP-AC (FRAP after photoConversion), we have shown that the ribosome-free pool of uL10 represents a population of proteins released from pre-existing ribosomes. Taken together, our data indicate that the presence of uL10 on the ribosomes is affected in stressed cells, thus it might be considered as a regulatory element responding to environmental fluctuations. 相似文献
33.
Strains of Rhizoctonia solani, a common soil-borne, pathogenic fungus of plants, are assigned to one of 11 anastomosis groups (AGs) based on the occurrence of imperfect fusions (anastomoses) between hyphae of a non-typed strain and a tester strain of one of the 11 AG's. Imperfect fusion is characterized by the death of one or more cells in each of the hyphae involved in the fusion. Although hyphae from branches of the same strain of JR. solani may fuse with each other (self-fusion), cell death does not occur. Cell death is accompanied by nuclear degradation and granulation, or plasmolysis of the cytoplasm, which often is not visible using bright-field microscopy. When the DNA-binding fluorochrome DAPI (4', 6-diamidino-2-phenylindole) is used and the hyphal fusions viewed under fluorescence microscopy, no nuclei are observed in fused hyphal cells from two strains of the same AG of R. solani Because DAPI reacts only with living nuclei, lack of staining is presumptive evidence that the fused cells are dead as a result of imperfect fusion. The use of DAPI reduces the time required for making AG determinations compared to standard methods because it eliminates the need to assess cell wall dissolution and cytoplasmic fusion. Also, it is not necessary to trace the hyphae involved in the fusion to their respective origins to ensure that self-fusion has not occurred. 相似文献
34.
PD Dr. med. Hanspeter Rohr Ute Seitter Jürgen Schmalbeck 《Cell and tissue research》1968,85(3):376-397
Zusammenfassung Einer weiblichen Maus wurde 3 Tage post partum 750 C 3H-Leucin i. p. injiziert. Zu verschiedenen Zeiten nach der Leucinapplikation wurden dem leicht narkotisierten Tier Gewebeteile der Milchdrüse entnommen und zu elektronenmikroskopischen Autoradiogrammen verarbeitet. An Hand der dabei gewonnenen Ergebnisse wurde versucht, den zeitlichen Ablauf der Milcheiweißbildung rechnerisch zu erfassen. 5 und 15 min nach der 3H-Leucinapplikation kann die Aktivität über dem rauhen endoplasmatischen Retikulum, nach 30 min über dem Golgi-Feld, und nach 240 min zur Hauptsache über den Lumina der Ausführungsgänge beobachtet werden. Die Halbwertszeit von markierten Proteinen im Ergastoplasma errechnete sich zu etwa 22 min, diejenige im Golgi-Feld zu etwa 3 Std.Die Voraussetzungen und derzeitigen Grenzen einer quantitativen elektronenmikroskopischen Autoradiographie werden diskutiert. Wegen der vielen möglichen Fehlerquellen wird die Berechnung der Kinetik der Milcheiweißbildung lediglich als Modell gewertet.
Ausgeführt mit Unterstützung durch die Deutsche Forschungsgemeinschaft.
Wesentliche Teile der Arbeit werden Von Ute Seitter der Medizinischen Fakultät der Universität Freiburg i. Br. als Inaugural-Dissertation vorgelegt. 相似文献
Summary A female mouse, 3 days post partum, was injected with 3H-leucine. After various intervals parts of the mammary gland were processed for electronmicroscopic autoradiograms, the results of which were mathematically evaluated in order to understand the temporal course of milk protein formation. After 5 and 15 minutes the leucine-activity is located mainly in the rough endoplasmic reticulum, after 30 minutes in the Golgi field and after 240 minutes in the lumina of the mammary ducts. The half-live time of labelled proteins in the rough endoplasmic reticulum is about 22 minutes, in the Golgi field about 3 hours.The preconditions and limitations of quantitative electronmicroscopic autoradiography are discussed. Because of the many possible sources of error, the calculations of the kinetics of protein synthesis and secretion in the mammary gland are merely regarded as a model.
Ausgeführt mit Unterstützung durch die Deutsche Forschungsgemeinschaft.
Wesentliche Teile der Arbeit werden Von Ute Seitter der Medizinischen Fakultät der Universität Freiburg i. Br. als Inaugural-Dissertation vorgelegt. 相似文献
35.
Colin PD Birch Ambrose C Chikukwa Kieran Hyder Victor J Del Rio Vilas 《BMC veterinary research》2009,5(1):1-14
Background
This paper explores the spatial distribution of sampling within the active surveillance of sheep scrapie in Great Britain. We investigated the geographic distribution of the birth holdings of sheep sampled for scrapie during 2002 – 2005, including samples taken in abattoir surveys (c. 83,100) and from sheep that died in the field ("fallen stock", c. 14,600). We mapped the birth holdings by county and calculated the sampling rate, defined as the proportion of the holdings in each county sampled by the surveys. The Moran index was used to estimate the global spatial autocorrelation across Great Britain. The contributions of each county to the global Moran index were analysed by a local indicator of spatial autocorrelation (LISA). 相似文献36.
PD Dr. rer. nat. R. Schwaab S. Rost J. Schröder C.R. Müller-Reible J. Oldenburg 《Medizinische Genetik》2008,20(2):190-196
Haemophilia A and B are caused by various mutations in the factor VIII (FVIII) and factor IX (FIX) genes, respectively. The clinical course of the disease is variable, dependent on the severity of the molecular defect. Nowadays, haemophilia patients can excellently be treated by plasma-derived or recombinant clotting factor concentrates. Thus, bleeding and its consequences can be almost completely prevented with nearly normal quality of life and life expectancy. The most severe complication of this treatment is the formation of antibodies (inhibitors) against the substituted clotting factor. The risk of inhibitor formation correlates significantly with specific mutation types that preclude endogenous factor VIII/IX protein synthesis and can be as high as 20–50%. The information on the expected clinical course is at present the most important indication for FVIII/IX gene analysis. Knowledge of the underlying FVIII/IX gene mutation further allows a reliable and fast carrier diagnosis in female relatives of patients with haemophilia. 相似文献
37.
Planta - Using a live-cell-imaging approach and autofluorescence-spectral imaging, we showed quantitative/qualitative fluctuations of chemical compounds within the meiocyte callose wall, providing... 相似文献
38.
Rick PD; Hubbard GL; Kitaoka M; Nagaki H; Kinoshita T; Dowd S; Simplaceanu V; Ho C 《Glycobiology》1998,8(6):557-567
The polysaccharide chains of enterobacterial common antigen (ECA) consist
of linear trisaccharide repeat units with the structure -->3)-
alpha-d-Fuc4NAc-(1-->4)-beta-d-ManNAcA-(1-->
4)-alpha-d-GlcNAc-(1-->, where Fuc4NAc is 4-acetamido-4,
6-dideoxy-d-galactose, ManNAcA is N - acetyl-d- mannosaminuronic acid, and
GlcNAc is N -acetyl-d-glucosamine. The major form of ECA (ECAPG) consists
of polysaccharide chains that are believed to be covalently linked to
diacylglycerol through phosphodiester linkage; the phospholipid moiety
functions to anchor molecules in the outer membrane. The ECA trisaccharide
repeat unit is assembled as a polyisoprenyl-linked intermediate which has
been tentatively identified as Fuc4NAc-ManNAcA-GlcNAc-
pyrophosphorylundecaprenol (lipid III). Subsequent chain-elongation
presumably occurs by a block-polymerization mechanism. However, the
identity of the polyisoprenoid carrier-lipid has not been established.
Accordingly, the current studies were conducted in an effort to
structurally characterize the polyisoprenyl lipid-carrier involved in ECA
synthesis. Isolation and characterization of the lipid carrier was
facilitated by the accumulation of a ManNAcA-GlcNAc-
pyrophosphorylpolyisoprenyl lipid (lipid II) in mutants of Salmonella
typhimurium defective in the synthesis of TDP-Fuc4NAc, the donor of Fuc4NAc
residues for ECA synthesis. Analyses of lipid II preparations by fast atom
bombardment tandem mass spectroscopy (FAB-MS/MS) resulted in the
identification of the lipid-carrier as the 55-carbon polyisoprenyl alcohol,
undecaprenol. These analyses also resulted in the identification of a novel
glycolipid which copurified with lipid II. FAB-MS/MS analyses of this
glycolipid revealed its structure to be 1,2-diacyl- sn
-glycero-3-pryophosphoryl-GlcNAc-ManNAcA (DGP- disaccharide). An
examination of purified ECAPGby phosphorus-31 nuclear magnetic resonance
spectroscopy confirmed that the polysaccharide chains are linked to
diacylglycerol through phosphodiester linkage. Thus, DGP-disaccharide does
not appear to be an intermediate in ECAPGsynthesis. Nevertheless, although
the available evidence clearly indicate that lipid II is a precursor of
DGP-disaccharide, the function of this novel glycolipid is not yet known,
and it may be an intermediate in the biosynthesis of a molecule other than
ECAPG.
相似文献
39.
Small cryptic plasmids of molecular weights ranging from 1 to 3 Mdal were detected by electron microscopy in Salmonella typhimurium strain LT2 (ColIb). They were divided into different size classes. Two of the cryptic plasmids were transferred simultaneously with ColIb to Escherichia coli.List of Abbreviations TES buffer
0.05 M tris-HCl pH 8.0, 0.05 M NaCl, 0.005 M Na2 EDTA
- TCG medium
tris-casamino acid-glucose medium
- cpm
counts per min 相似文献
40.
Summary The apical portion of the uterine lining of the ovoviviparous fire salamander, Salamandra salamandra, was studied by the freeze-fracture technique in conjunction with the polyene antibiotic filipin. Filipin-sterol complexes were found in the luminal plasmalemma and in the membranes limiting the mucous secretory granules typical of this epithelium. In all females, but particularly in non-pregnant females, more or less discrete clusters of filipinsterol complexes were occasionally found overlying heavily affected secretory granules. The findings are discussed with regard to comparable results (Orci et al. 1980) based on the examination of collapsed and stretched urinary bladders of toads.We are indebted to Mrs. K. Ott for excellent technical assistance, to Miss E.S. MacLure for linguistic corrections and to Dr. J.E. Grady of the Upjohn Co., Kalamazoo, Michigan USA, for kindly providing the filipin 相似文献