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31.
Subcellular localization of DNA-binding protein BA by immunofluorescence and immunoelectron microscopy 总被引:3,自引:2,他引:1 下载免费PDF全文
Nonhistone protein BA has been shown to decrease in amount in the chromatin of growth- stimulated normal rat liver (Yeoman et al. 1975. Cancer Res. 35:1249-1255) and in mitogen-stimulated normal human lymphocytes (Yeoman et al. 1976. Exp. Cell Res. 100:47- 55.). Subsequently, protein BA was purified and was shown to prefer to bind to double- stranded A-T-rich DNAs (Catino et al. 1978. Biochemistry. 17:983-987.). Immunization of rabbits with highly purified protein BA has resulted in the production of a specific antibody. A specific immunoreactivity for chromosomal protein BA has been demonstrated by immunoelectrophoresis and double antibody immunoprecipitation analysis with rabbit anti-BA immunoglobulin and IgG fractions. Light microscope examination of normal rat liver crysections by the indirect immunofluorescence procedure has demonstrated a cytoplasmic as well as a nuclear localization for protein BA with a pronounced perinucleolar fluorescence. Immunoelectron microscopy employing the peroxidase antiperoxidase method of antigen localization has confirmed the immunofluorescence data and has show a heterochromatin localization for protein BA. The relationship of the localization of protein BA to gene control in quiescent cells or to configurations of heterochromatin as well as the marked reduction in the amounts of protein BA which occur in stimulated growth states remains to be defined. 相似文献
32.
The metabolism of protozoan parasites of the Leishmania genus is strongly based on amino acid consumption, but little is known about amino acid uptake in these organisms. In the present work, we identified a Leishmania amazonensis gene (La-PAT1) encoding a putative amino acid transporter that belongs to the amino acid/auxin permease family, a group of H(+)/amino acid symporters. This single copy gene is upregulated in amastigotes, the life cycle stage found in the mammalian host. La-PAT1 putative orthologous sequences were identified in Leishmania infantum, Leishmania donovani, Leishmania major and Trypanosoma. 相似文献
33.
Maize endosperm ADP-glucose pyrophosphorylase SHRUNKEN2 and BRITTLE2 subunit interactions 总被引:4,自引:0,他引:4 下载免费PDF全文
ADP-glucose pyrophosphorylase (AGP) represents a key regulatory step in polysaccharide synthesis in organisms ranging from bacteria to plants. Higher plant AGPs are complex in nature and are heterotetramers consisting of two similar but distinct subunits. How the subunits are assembled into enzymatically active polymers is not yet understood. Here, we address this issue by using naturally occurring null mutants of the Shrunken2 (Sh2) and Brittle2 (Bt2) loci of maize as well as the yeast two-hybrid expression system. In the absence of the maize endosperm large AGP subunit (SH2), the BT2 subunit remains as a monomer in the developing endosperm. In contrast, the SH2 protein, in the absence of BT2, is found in a complex of 100 kD. A direct interaction between SH2 and BT2 was proven when they were both expressed in yeast. Several motifs are essential for SH2:BT2 interaction because truncations removing the N or C terminus of either subunit eliminate SH2:BT2 interactions. Analysis of subunit interaction mutants (sim) also identified motifs essential for protein interactions. 相似文献
34.
Cytoplasmic tails of SialT2 and GalNAcT impose their respective proximal and distal Golgi localization 总被引:2,自引:0,他引:2
Complex glycolipid synthesis is catalyzed by different glycosyltransferases resident of the Golgi complex. Most of them are type II membrane proteins comprising a lumenal, C-terminal domain linked to an N-terminal domain (Ntd) constituted by a short cytoplasmic tail (ct), a transmembrane, and a lumenal stem regions. They concentrate selectively in different sub-Golgi compartments, in an overlapped manner, acting in succession in the addition of sugars to acceptor glycolipids. The Ntds are sufficient to localize glycosyltransferases in the Golgi complex, but it is not clear whether they also confer selective concentration in sub-Golgi compartments. Here, we studied whether the Ntd of SialT2, localized in the proximal Golgi, and the one of GalNAcT, a trans/TGN Golgi-concentrated enzyme, concentrate reporter proteins in the corresponding sub-Golgi compartment. The sub-Golgi concentration of the Ntds fused to spectral variants of the GFP was determined in CHO-K1 cells from their behavior upon addition of brefeldin A. Fluorescence microscopy and subcellular fractionation showed that the SialT2 Ntd concentrates in a proximal sub-Golgi compartment - and that of GalNAcT in TGN elements. Exchanging the transmembrane region and the cts of SialT2 and GalNAcT indicates that information for proximal or distal Golgi concentration is associated with the cts. 相似文献
35.
Uliana A. Ukrainskaja Michael G. Pimenov Eugene V. Kljuykov 《Nordic Journal of Botany》2013,31(6):648-665
The new species Semenovia pulvinata Pimenov & Kljuykov, S. dissectifolia Ukrainskaja & Kljuykov, S. imbricata Ukrainskaja & Kljuykov, and S. vachanica Ukrainskaja & Kljuykov from the mountains of Pamiro‐Alai, Tajikistan and adjacent Afghanistan, are described and illustrated. For the Chinese species S. millefolia (Diels) V. M.Vinogr. & Kamelin, also known as Heracleum millefolium Diels, the correct name is S. torilifolia (H. Boissieu) Pimenov comb. nov. based on Peucedanum torilifolium H. Boissieu. For another closely related Chinese species, Peucedanum malcolmii Hemsl. & H. Pearson, also belonging to Semenovia, the new combination S. malcolmii (Hemsl. & H. Pearson) Pimenov is proposed. Heracleum thomsonii C. B. Clarke var. glabrior C. B. Clarke from Kashmir (Ladakh) is regarded as an independent species of Semenovia, S. glabrior (C. B. Clarke) Pimenov & Kljuykov. 相似文献
36.
Anna Cleta Croce Uliana De Simone Mariapia Vairetti Andrea Ferrigno Giovanni Bottiroli 《Photochemical & photobiological sciences》2007,6(11):1202-1209
Autofluorescence response to oxygen supply modulation has been investigated in livers of rats under the hypermetabolic state associated to a pathological condition-hyperthyroidism-that is known to enhance hepatocyte metabolic activities involving both NAD, i.e. oxidative pathways engaged in ATP synthesis, and NADP, i.e. reductive bio-synthesis and antioxidant functions. Experiments have been performed on rats in normal condition or submitted to long-term thyroxine (T(4)) administration. Histological inspection did not show any appreciable morphological alteration in liver parenchyma; biochemical analysis indicated an increase in both NADP(+) and NADPH contents. Autofluorescence properties have been monitored in vivo, via a fiber optic probe, on exposed livers both during induction of global ischemia and after restoration of blood circulation. Alteration of oxygen supply modulated liver autofluorescence properties, mainly as to NAD(P)H contribution, in dependence of changes in pyridine coenzymes redox state. With respect to euthyroid, hyperthyroid rat livers exhibited higher autofluorescence signals in all phases of the experiment, and a faster signal decay time upon reoxygenation. The results have been interpreted on the basis of a larger content of NADPH-the coenzyme not directly oxidized in respiratory processes and likely providing an almost constant autofluorescence background contribution-and of uncoupling effects facilitating the respiratory NADH oxidation, associated with the hyperthyroid condition. The results obtained in the liver hypermetabolic model provide interesting perspectives for a further improvement of the diagnostic implications of autofluorescence. 相似文献
37.
Xavier Didelot David W Eyre Madeleine Cule Camilla LC Ip M Azim Ansari David Griffiths Alison Vaughan Lily O'Connor Tanya Golubchik Elizabeth M Batty Paolo Piazza Daniel J Wilson Rory Bowden Peter J Donnelly Kate E Dingle Mark Wilcox A Sarah Walker Derrick W Crook Tim E A Peto Rosalind M Harding 《Genome biology》2012,13(12):R118
Background
The control of Clostridium difficile infection is a major international healthcare priority, hindered by a limited understanding of transmission epidemiology for these bacteria. However, transmission studies of bacterial pathogens are rapidly being transformed by the advent of next generation sequencing.Results
Here we sequence whole C. difficile genomes from 486 cases arising over four years in Oxfordshire. We show that we can estimate the times back to common ancestors of bacterial lineages with sufficient resolution to distinguish whether direct transmission is plausible or not. Time depths were inferred using a within-host evolutionary rate that we estimated at 1.4 mutations per genome per year based on serially isolated genomes. The subset of plausible transmissions was found to be highly associated with pairs of patients sharing time and space in hospital. Conversely, the large majority of pairs of genomes matched by conventional typing and isolated from patients within a month of each other were too distantly related to be direct transmissions.Conclusions
Our results confirm that nosocomial transmission between symptomatic C. difficile cases contributes far less to current rates of infection than has been widely assumed, which clarifies the importance of future research into other transmission routes, such as from asymptomatic carriers. With the costs of DNA sequencing rapidly falling and its use becoming more and more widespread, genomics will revolutionize our understanding of the transmission of bacterial pathogens. 相似文献38.
Komor U Bielecki P Loessner H Rohde M Wolf K Westphal K Weiss S Häussler S 《Microbes and infection / Institut Pasteur》2012,14(11):951-958
The ability of opportunistic bacterial pathogens to grow in biofilms is decisive in the pathogenesis of chronic infectious diseases. Growth within biofilms does not only protect the bacteria against the host immune system but also from the killing by antimicrobial agents. Here, we introduce a mouse model in which intravenously administered planktonic Pseudomonas aeruginosa bacteria are enriched in transplantable subcutaneous mouse tumors. Electron microscopy images provide evidence that such bacteria reside in the tumor tissue within biofilm structures. Immunohistology furthermore demonstrated that infection of the tumor tissue elicits a host response characterized by strong neutrophilic influx. Interestingly, the biofilm defective PA14 pqsA transposon mutant formed less biofilm in vivo and was more susceptible to clearance by intravenous ciprofloxacin treatment as compared to the wild-type control. In conclusion, we have established an experimentally tractable model that may serve to identify novel bacterial and host factors important for in vivo biofilm formation and to re-evaluate bactericidal and anti-biofilm effects of currently used and novel antibacterial compounds. 相似文献
39.
Camila S. Ramos Jenicer K.U. Yokoyama-Yasunaka Cristina Guerra-Giraldez Helen P. Price Renato A. Mortara Deborah F. Smith Silvia R.B. Uliana 《Experimental parasitology》2011,127(1):228-237
The META cluster of Leishmania amazonensis contains both META1 and META2 genes, which are upregulated in metacyclic promastigotes and encode proteins containing the META domain. Previous studies defined META2 as a 48.0-kDa protein, which is conserved in other Leishmania species and in Trypanosoma brucei. In this work, we demonstrate that META2 protein expression is regulated during the Leishmania life cycle but constitutive in T. brucei. META2 protein is present in the cytoplasm and flagellum of L. amazonensis promastigotes. Leishmania META2-null replacement mutants are more sensitive to oxidative stress and, upon heat shock, assume rounded morphology with shortened flagella. The increased susceptibility of null parasites to heat shock is reversed by extra-chromosomal expression of the META2 gene. Defective Leishmania promastigotes exhibit decreased ability to survive in macrophages. By contrast, META2 expression is decreased by 80% in RNAi-induced T. brucei bloodstream forms with no measurable effect on survival or resistance to heat shock. 相似文献
40.
Rodrigo da Silva Maffei Jenicer K. U. Yokoyama-Yasunaka Danilo Ciccone Miguel Silvia Reni Bortolin Uliana Breno Pannia Espósito 《Biometals》2009,22(6):1095-1101
In this study, Cu(II) complexes with fluorinated ligands were produced aiming at the development of new, less toxic antileishmanial
metallodrugs. Complexes of the general formula CuL2 (L = lactate, trifluorolactate, 2-hydroxyisobutyrate, trifluoro-2-hydroxyisobutyrate) were synthesized in methanolic medium,
purified by crystallization and characterized by elemental analysis and electronic and infrared spectroscopies. In vitro experiments
with Leishmania amazonensis promastigotes showed that the trifluorolactate derivative more active than its non-fluorinated counterpart. Our results indicate
that fluorinated chelators may be interesting to increase metal toxicity and/or open new paths for metallodrug chemotherapy
against leishmaniasis. 相似文献