scholarly journals Functional Interactions of Ribosomal Intersubunit Bridges in Saccharomyces cerevisiae

Genetics ◽  
2019 ◽  
Vol 213 (4) ◽  
pp. 1329-1339
Author(s):  
Tiina Tamm ◽  
Ivan Kisly ◽  
Jaanus Remme
Keyword(s):  
Genetic Interaction ◽  
Minor Role ◽  
Ribosomal Subunits ◽  
Eukaryotic Translation ◽  
Functional Interactions ◽  
Yeast Strains ◽  
Evolutionary Success ◽  
A Minor

Ribosomes of Archaea and Eukarya share higher homology with each other than with bacterial ribosomes. For example, there is a set of 35 r-proteins that are specific only for archaeal and eukaryotic ribosomes. Three of these proteins—eL19, eL24, and eL41—participate in interactions between ribosomal subunits. The eukaryote-specific extensions of r-proteins eL19 and eL24 form two intersubunit bridges eB12 and eB13, which are present only in eukaryotic ribosomes. The third r-protein, eL41, forms bridge eB14. Notably, eL41 is found in all eukaryotes but only in some Archaea. It has been shown that bridges eB12 and eB13 are needed for efficient translation, while r-protein eL41 plays a minor role in ribosome function. Here, the functional interactions between intersubunit bridges were studied using budding yeast strains lacking different combinations of the abovementioned bridges/proteins. The growth phenotypes, levels of in vivo translation, ribosome–polysome profiles, and in vitro association of ribosomal subunits were analyzed. The results show a genetic interaction between r-protein eL41 and the eB12 bridge-forming region of eL19, and between r-proteins eL41 and eL24. It was possible to construct viable yeast strains with Archaea-like ribosomes lacking two or three eukaryote-specific bridges. These strains display slow growth and a poor translation phenotype. In addition, bridges eB12 and eB13 appear to cooperate during ribosome subunit association. These results indicate that nonessential structural elements of r-proteins become highly important in the context of disturbed subunit interactions. Therefore, eukaryote-specific bridges may contribute to the evolutionary success of eukaryotic translation machinery.

scholarly journals In Vitro and In Vivo Biology of Recombinant Adenovirus Vectors with E1, E1/E2A, or E1/E4 Deleted

1998 ◽  
Vol 72 (3) ◽  
pp. 2022-2032 ◽  
Author(s):  
M. Lusky ◽  
M. Christ ◽  
K. Rittner ◽  
A. Dieterle ◽  
D. Dreyer ◽  
...  
Keyword(s):  
Recombinant Adenovirus ◽  
Virus Genome ◽  
Minor Role ◽  
Immunodeficient Mice ◽  
Viral Genomes ◽  
Viral Genes ◽  
Adenovirus Vectors ◽  
A Minor

ABSTRACT Isogenic, E3-deleted adenovirus vectors defective in E1, E1 and E2A, or E1 and E4 were generated in complementation cell lines expressing E1, E1 and E2A, or E1 and E4 and characterized in vitro and in vivo. In the absence of complementation, deletion of both E1 and E2A completely abolished expression of early and late viral genes, while deletion of E1 and E4 impaired expression of viral genes, although at a lower level than the E1/E2A deletion. The in vivo persistence of these three types of vectors was monitored in selected strains of mice with viral genomes devoid of transgenes to exclude any interference by immunogenic transgene-encoded products. Our studies showed no significant differences among the vectors in the short-term maintenance and long-term (4-month) persistence of viral DNA in liver and lung cells of immunocompetent and immunodeficient mice. Furthermore, all vectors induced similar antibody responses and comparable levels of adenovirus-specific cytotoxic T lymphocytes. These results suggest that in the absence of transgenes, the progressive deletion of the adenovirus genome does not extend the in vivo persistence of the transduced cells and does not reduce the antivirus immune response. In addition, our data confirm that, in the absence of transgene expression, mouse cellular immunity to viral antigens plays a minor role in the progressive elimination of the virus genome.

scholarly journals New Insight into Amphotericin B Resistance in Aspergillus terreus

2013 ◽  
Vol 57 (4) ◽  
pp. 1583-1588 ◽  
Author(s):  
Gerhard Blum ◽  
Caroline Hörtnagl ◽  
Emina Jukic ◽  
Thomas Erbeznik ◽  
Thomas Pümpel ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Molecular Basis ◽  
Aspergillus Terreus ◽  
Minor Role ◽  
Content Type ◽  
Ergosterol Content ◽  
Disseminated Aspergillosis ◽  
A Minor

ABSTRACTAmphotericin B (AMB) is the predominant antifungal drug, but the mechanism of resistance is not well understood. We compared thein vivovirulence of an AMB-resistantAspergillus terreus(ATR) isolate with that of an AMB-susceptibleA. terreusisolate (ATS) using a murine model for disseminated aspergillosis. Furthermore, we analyzed the molecular basis of intrinsic AMB resistancein vitroby comparing the ergosterol content, cell-associated AMB levels, AMB-induced intracellular efflux, and prooxidant effects between ATR and ATS. Infection of immunosuppressed mice with ATS or ATR showed that the ATS strain was more lethal than the ATR strain. However, AMB treatment improved the outcome in ATS-infected mice while having no positive effect on the animals infected with ATR. Thein vitrodata demonstrated that ergosterol content is not the molecular basis for AMB resistance. ATR absorbed less AMB, discharged more intracellular compounds, and had better protection against oxidative damage than the susceptible strain. Our experiments showed that ergosterol content plays a minor role in intrinsic AMB resistance and is not directly associated with intracellular cell-associated AMB content. AMB might exert its antifungal activity by oxidative injury rather than by an increase in membrane permeation.

Endothelial nitric oxide synthase plays a minor role in inhibition of arterial thrombus formation

2005 ◽  
Vol 93 (06) ◽  
pp. 1161-1167 ◽  
Author(s):  
Burcin Özüyaman ◽  
Susanne Küsters ◽  
Elisabeth Kirchhoff ◽  
Rüdiger Scharf ◽  
Jürgen Schrader ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Thrombus Formation ◽  
Surface Expression ◽  
No Synthase ◽  
Minor Role ◽  
Endothelial No Synthase ◽  
Tail Tip ◽  
A Minor

SummaryEndothelial NO synthase (eNOS) expressed in the vascular en-dothelium or formed within platelets was postulated to inhibit platelet activation and aggregation. We have assessed the role of eNOS in platelet aggregation in vitro and in vivo by comparison of WT and eNOS-/- mice. Aggregometer studies revealed that collagen over a concentration range of 0.36–10 µg aggregated WT and eNOS-/- platelets to the same extent (10 µg: WT 86.7±4.7%, eNOS-/- 91±12%, n=6). Collagen treatment did not result in a significant increase in cGMP formation and VASP phosphorylation. Thrombin-induced P-selectin surface expression was unchanged in eNOS-/- platelets. In line with these findings no eNOS protein was detectable within the platelets of WT mice. In vivo, bleeding time after tail tip resection tended to be shorter in eNOS/- mice (WT: 116±35 s; eNOS-/- 109±37 s, n.s). Similarly, time to occlusion of the A.carotis after focal induction of thrombosis was 501±76 s (WT) and 457±95 s (eNOS-/-) (n.s.). These data demonstrate that eNOS-deficiency minimally affects platelet aggregation and is not associated with accelerated arterial thrombosis in vivo. Thus, in the mouse endothelial NO synthase does not play a major role in the autocrine modulation of platelet function and in thrombosis of conduit vessels in vivo.

The Different Genotoxicity of P-Dichlorobenzene in Mouse and Rat: Measurement of the in Vivo and in Vitro Covalent Interaction with Nucleic Acids

1989 ◽  
Vol 75 (4) ◽  
pp. 305-310 ◽  
Author(s):  
Giovanna Lattanzi ◽  
Silvana Bartoli ◽  
Bruna Bonora ◽  
Annamaria Colacci ◽  
Sandro Grilli ◽  
...  
Keyword(s):  
Mouse Liver ◽  
Covalent Binding ◽  
Minor Role ◽  
Covalent Interaction ◽  
Male Wistar Rats ◽  
Mixed Function Oxidase System ◽  
Index Value ◽  
A Minor

Twenty-two hours after i.p. injection to male Wistar rats and BALB/c mice para-dichlorobenzene (p-DCB) is bound covalently to DNA from liver, kidney, lung and stomach of mice but not of rats. DNA adducts in mouse liver are repaired in seventy-two hours. The covalent binding index value, calculated on the labelling of mouse liver DNA, classifies p-DCB as a weak initiator with an oncogenic activity lower than that of chlorobenzene. The labelling of RNA and proteins from the different organs of both species is, however, low. In vitro interaction with calf thymus DNA mediated by mouse and rat microsomes from liver and lung did occur. Binding extent was strongly reduced by addition of 2-diethylaminoethyl-2,2-diphenylvalerate hydrochloride (SKF 525-A) to the microsomal standard incubation mixture, whereas it was enhanced by adding GSH. Cytosolic fractions from kidney and lung were able to induce binding of p-DCB to DNA to a lower extent with respect to microsome-mediated binding. These results indicate that microsomal mixed function oxidase system and microsomal GSH-transferases can be involved in overall activating metabolism whereas cytosolic GSH-transferases play a minor role. This study, which is a part of a structure-activity relationship approach on benzene and its haloderivatives, provides the first evidence of genotoxicity of p-DCB in mammalian cell. It allows to partly explain variations of susceptibility of different species to hepatocarcinogenesis and of hepatotoxicity of different isomers.

scholarly journals Inhibitors of the Bub1 spindle assembly checkpoint kinase: Synthesis of BAY-320 and comparison with 2OH-BNPP1

2020 ◽  
Author(s):  
Ilma Amalina ◽  
Ailsa Bennett ◽  
Helen Whalley ◽  
David Perera ◽  
Joanne C. McGrail ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Kinase Activity ◽  
Spindle Assembly ◽  
Minor Role ◽  
Chromosome Alignment ◽  
High Concentrations ◽  
A Minor ◽  
Target Effects

SummaryBub1 is a serine/threonine kinase proposed to function centrally in both mitotic chromosome alignment and the spindle assembly checkpoint (SAC), however its role remains controversial. Although it is well documented that Bub1 phosphorylation of Histone 2A at T120 (H2ApT120) recruits Sgo1/2 to kinetochores, the requirement of its kinase activity for chromosome alignment and the SAC is debated. As small-molecule inhibitors can be invaluable tools for investigation of kinase function, we decided to evaluate the relative potential of two agents (2OH-BNPPI and BAY-320) as Bub1 inhibitors. After confirming that both agents inhibit Bub1 in vitro, we developed a cell based-assay to specifically measure Bub1 inhibition in vivo. For this assay we overexpressed a fusion of Histone 2B and the Bub1 kinase region (Bub1C) tethering it in close proximity to H2A, which generated a strong ectopic H2ApT120 signal along chromosome arms. The ectopic signal generated from Bub1C activity was effectively inhibited by BAY-320, but not 2OH-BNPP1. In addition, only BAY-320 was able to inhibit endogenous Bub1-mediated Sgo1 localisation. Preliminary experiments using BAY-320 suggested a minor role for Bub1 kinase activity in chromosome alignment and the SAC, however results suggest that BAY-320 may exhibit off-target effects at the concentration required to demonstrate these outcomes. In conclusion, 2OH-BNPP1 may not be an effective Bub1 inhibitor in vivo, and while BAY-320 is able to inhibit Bub1 in vivo, the high concentrations required and potential for off-target effects highlight the ongoing need for improved Bub1 inhibitors.

New Concepts in Phototherapy: Photoisomerization of Bilirubin IXα and Potential Toxic Effects of Light

PEDIATRICS ◽  
1980 ◽  
Vol 65 (4) ◽  
pp. 740-750 ◽  
Author(s):  
Arnold N. Cohen ◽  
J. Donald Ostrow
Keyword(s):  
Side Effects ◽  
Neonatal Jaundice ◽  
Toxic Effects ◽  
Minor Role ◽  
Major Mechanism ◽  
New Information ◽  
New Concepts ◽  
A Minor

New information is summarized, indicating that configurational photoisomerization of bilirubin at the 5 and 15 carbon bridges is the major mechanism of bilirubin photocatabolism in vivo, and that singlet oxygen photooxidation plays only a minor role. The literature is reviewed concerning potentially damaging photodynamic reactions that are observed in vitro with vitamins, proteins, lipids, and nucleic acids, and their possible relationship to the limited number of toxic side-effects that have been detected with clinical phototherapy of neonatal jaundice. Secondary toxic effects, mediated by bilirubin photoderivatives or by retina-neuroendocrine pathways are also considered. Areas requiring further investigation are delineated.

scholarly journals Integration in oncogenes plays only a minor role in determining the in vivo distribution of HIV integration sites before or during suppressive antiretroviral therapy

2021 ◽  
Vol 17 (4) ◽  
pp. e1009141
Author(s):  
John M. Coffin ◽  
Michael J. Bale ◽  
Daria Wells ◽  
Shuang Guo ◽  
Brian Luke ◽  
...  
Keyword(s):  
Antiretroviral Therapy ◽  
Clonal Expansion ◽  
Minor Role ◽  
Hiv Persistence ◽  
Integration Sites ◽  
Selection For ◽  
A Minor ◽  
Hiv Integration

HIV persists during antiretroviral therapy (ART) as integrated proviruses in cells descended from a small fraction of the CD4+ T cells infected prior to the initiation of ART. To better understand what controls HIV persistence and the distribution of integration sites (IS), we compared about 15,000 and 54,000 IS from individuals pre-ART and on ART, respectively, with approximately 395,000 IS from PBMC infected in vitro. The distribution of IS in vivo is quite similar to the distribution in PBMC, but modified by selection against proviruses in expressed genes, by selection for proviruses integrated into one of 7 specific genes, and by clonal expansion. Clones in which a provirus integrated in an oncogene contributed to cell survival comprised only a small fraction of the clones persisting in on ART. Mechanisms that do not involve the provirus, or its location in the host genome, are more important in determining which clones expand and persist.

Role of Thromboxane A2 as a Mediator of Platelet-Activating-Factor-Induced Aggregation of Human Platelets

1989 ◽  
Vol 77 (1) ◽  
pp. 99-103 ◽  
Author(s):  
R. K. McCulloch ◽  
J. Summers ◽  
R. Vandongen ◽  
I. L. Rouse
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activating Factor ◽  
Thromboxane A2 ◽  
Human Platelets ◽  
Minor Role ◽  
A Minor ◽  
Induced Aggregation

1. At present it is unclear whether platelet-activating-factor (PAF)-induced aggregation is mediated by thromboxane. To obtain further information about this event we have compared the affects of aspirin on platelet aggregation and secretion induced by PAF and collagen. 2. Collagen and PAF induced aggregation and secretion in human platelets in a dose-related manner. 3. Aspirin inhibited the magnitude of both platelet aggregation and secretion induced by PAF and collagen, but the degree of inhibition was much greater for collagen. 4. Aspirin strongly inhibited the aggregation rate of collagen-induced platelet aggregation, but had no measurable effect on the rate of PAF-induced aggregation. 5. Inconsistencies reported in previous studies of the effect of aspirin on PAF-induced platelet aggregation may be explained, in part, by the doses of PAF used and the method of inactivating cyclo-oxygenase (in vitro compared with in vivo). 6. Our results suggest that the initial events of PAF-induced aggregation are independent of thromboxane A2 formation and that thromboxane A2 plays only a minor role in the later phase of PAF-induced aggregation.

Pharmacological characterization of airway smooth muscle responses to antigen in ascaris-sensitive dogs

1986 ◽  
Vol 64 (11) ◽  
pp. 1361-1367 ◽  
Author(s):  
M. S. Kannan ◽  
C. Davis ◽  
A. Sankaranarayanan ◽  
A. R. C. Ladenius ◽  
L. Kannan
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Smooth Muscle Contraction ◽  
Airway Responsiveness ◽  
Antigen Challenge ◽  
Minor Role ◽  
Pharmacological Characterization ◽  
A Minor

The dog model of ascaris airway sensitivity was chosen because of its frequency and its immunologic similarity to the human atopic asthmatic state. We studied the mediators of the antigen-induced airway response in vitro and the alterations in the in vivo and in vitro responsiveness to spasmogens evoked by antigen challenge. A myogenic basis of altered reactivity was suggested by the following: (i) tetrodotoxin-insensitive spontaneous active tone; (ii) phasic contractions of airway smooth muscle; and (iii) responsiveness to leukotrienes C4 and D4. The pharmacologic characteristics of the antigen-induced airway smooth muscle contraction in vitro were similar to those induced by arachidonic acid and the leukotrienes only in some respects but were clearly different from those induced by compound 48/80. This suggested a predominant role for arachidonate lipoxygenase products. Histamine apeared to play a minor role in the antigen response. Comparisons were made between antigen-induced responses of actively and passively sensitized airways tissues. In the latter, histamine release appeared to contribute to the initial antigen-induced contraction and, unlike in actively sensitized airways, the responses were easily densensitized to repeated challenge. Alterations of airway responsiveness were demonstrated in vivo to acetylcholine and 5-HT following antigen challenge of highly ascaris-sensitive dogs. In vitro studies of passively sensitized muscle showed selectively enhanced response to 5-HT following antigen challenge. These studies suport the presence of altered myogenic properties of airway smooth muscle and nonspecific increased airway responsiveness in this animal model.

scholarly journals Integration in or Near Oncogenes Plays Only a Minor Role in Determining the in Vivo Distribution of HIV Integration Sites Before or During Suppressive Antiretroviral Therapy

2020 ◽  
Author(s):  
John M. Coffin ◽  
Michael J. Bale ◽  
Daria Wells ◽  
Shuang Guo ◽  
Brian Luke ◽  
...  
Keyword(s):  
Antiretroviral Therapy ◽  
Minor Component ◽  
Minor Role ◽  
Growth And Survival ◽  
Integration Sites ◽  
Highly Expressed Genes ◽  
Infected Cells ◽  
A Minor

AbstractHIV persists during antiretroviral therapy (ART) as integrated proviruses in cells descended from a small fraction of the CD4+ T cells infected prior to the initiation of ART. To better understand what controls HIV persistence and the distribution of integration sites (IS), we compared about 16,000 and 54,000 IS from individuals pre-ART and on ART, respectively, with approximately 385,000 IS from PBMC infected in vitro. The distribution of IS in vivo is quite similar to the distribution in PBMC, modified by selection against proviruses in expressed genes, by selection for proviruses integrated into one of 6 specific genes, and by clonal expansion. The clones in which a provirus integrated in an oncogene contributed to the survival of the clone comprise only a small fraction of the clones that persist in HIV-infected individuals on ART. Mechanisms that do not involve the provirus, or its location in the host genome, are more important in determining which clones expand and persist.Author SummaryIn HIV-infected individuals, a small fraction of the infected cells persist and divide. This reservoir persists on ART and can rekindle the infection if ART is discontinued. Because the number of possible sites of HIV DNA integration is very large, each infected cell, and all of its descendants, can be identified by the site where the provirus is integrated (IS). To understand the selective forces that determine the fates of infected cells in vivo, we compared the distribution of HIV IS in freshly-infected cells to cells from HIV-infected donors sampled both before and during ART. We found that, as has been previously reported, integration favors highly-expressed genes. However, over time the fraction of cells with proviruses integrated in highly-expressed genes decreases, implying that they grow less well. There are exceptions to this broad negative selection. When a provirus is integrated in a specific region in one of six genes, the proviruses affect the expression of the target gene, promoting growth and/or survival of the cell. Although this effect is striking, it is only a minor component of the forces that promote the growth and survival of the population of infected cells during ART.

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