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1.
J Shoshani 《Molecular biology and evolution》1986,3(3):222-242
In an attempt to resolve the "bushy" part at the root of the eutherian tree, 182 nondental morphological characters from 100 species (79 extant and 21 extinct; 98 mammalian and 2 nonmammalian) were analyzed using two maximum-parsimony tree-building algorithms. Parallel analyses of 2,258 pairwise immunodiffusion comparisons with chicken antisera on 101 mammalian species and of amino acid sequence data of alpha and beta hemoglobins and other published protein sequences were also carried out. The morphological and molecular phylogenies agree in depicting the infraclass Eutheria as consisting of five major clades (thus resolving part of the "bush"). Rates of evolution were also found to be similar in the two types of phylogenies. 相似文献
2.
M Bushfield I Shoshani M Cifuentes D Stübner R A Johnson 《Archives of biochemistry and biophysics》1990,278(1):88-98
The effects of ribo- and deoxyribonucleic acids on the activity of detergent-dispersed adenylate cyclases from rat and bovine brain were examined. Mn2+ (10 mM)-activated adenylate cyclase was inhibited by micromolar concentrations of poly(A) (IC50 congruent to 0.45 microM). This inhibition was directly due to poly(A) and was not mediated by: (a) protein contamination of the poly(A) preparation, (b) metal chelation, (c) formation of an acid-soluble inhibitor of adenylate cyclase, (d) effects on the specific activity of [alpha-32P]ATP, (e) competition with MnATP for binding to adenylate cyclase, or (f) diversion of substrate to an alternate polymerase reaction. Inhibition of adenylate cyclase by poly(A) was on the enzyme's catalytic unit, as purified preparations of the enzyme from bovine brain were inhibited by poly(A). This inhibition by poly(A) was not likely mediated via the enzyme's "P"-site, through which activated forms of the enzyme are selectively inhibited by specific adenosine phosphates. In contrast with inhibition by the "P"-site agonist 3' AMP, inhibition of adenylate cyclase by poly(A) was slow in onset and was not reversible by dilution and showed a different metal-dependence. Inhibition of adenylate cyclase was relatively specific for poly(A) as poly(U) caused less than 50% inhibition and deoxyribonucleic acids had no effect. The potency and specificity of the inhibition of adenylate cyclase by poly(A) imply a biochemically interesting interaction that is possibly also of physiological significance. 相似文献
3.
Itzhak Zander Ester Shmidov Shira Roth Yossi Ben-David Irit Shoval Sivan Shoshani Amos Danielli Ehud Banin 《Environmental microbiology》2020,22(12):5048-5057
Toxin–antitoxin (TA) systems are small genetic modules usually consisting of two elements—a toxin and an antitoxin. The abundance of TA systems among various bacterial strains may indicate an important evolutionary role. Pseudomonas aeruginosa, which can be found in a variety of niches in nature, is an opportunistic pathogen for various hosts. While P. aeruginosa strains are very versatile and diverse, only a few TA systems were characterized in this species. Here, we describe a newly characterized TA system in P. aeruginosa that is encoded within the filamentous Pf4 prophage. This system, named PfiT/PfiA, is a homologue of the ParE/YefM TA system. It is a type II TA system, in which the antitoxin is a protein that binds the toxic protein and eliminates the toxic effect. PfiT/PfiA carries several typical type II characteristics. Specifically, it constitutes two small genes expressed in a single operon, PfiT inhibits growth and PfiA eliminates this effect, PfiA binds PfiT, and PfiT expression results in elongated cells. Finally, we assigned a novel function to this TA system, where an imbalance between PfiT and PfiA, favouring the toxin, resulted in cell elongation and an increase in virion production. 相似文献
4.
V. Calderón A. Lázaro R.G. Contreras L. Shoshani C. Flores-Maldonado L. González-Mariscal G. Zampighi M. Cereijido 《The Journal of membrane biology》1998,164(1):59-69
Tight junctions (TJs) are cell-to-cell contacts made of strands, which appear as ridges on P faces and complementary furrows
on E faces on freeze fracture replicas. Evidences and opinions on whether these strands are composed of either membrane-bound
proteins or lipid micelles are somewhat varied. In the present work we alter the lipid composition of Madin-Darby canine kidney
monolayers using a novel approach, while studying (i) their transepithelial electrical resistance, a parameter that depends
on the degree of sealing of the TJs; (ii) the apical-to-basolateral flux of 4 kD fluorescent dextran (JDEX), that reflects the permeability of the intercellular spaces; (iii) the ability of TJs to restrict apical-to-basolateral
diffusion of membrane lipids; and (iv) the pattern of distribution of endogenous and transfected occludin, the sole membrane
protein presently known to form part of the TJs. We show that changing the total composition of phospholipids, sphingolipids,
cholesterol and the content of fatty acids, does not alter TER nor the structure of the strands. Interestingly, enrichment
with linoleic acid increases the JDEX by 631%. The fact that this increase is not reflected in a decrease of TER, suggests that junctional strands do not act as
simple resistive elements but may contain mobile translocating mechanisms.
Received: 7 November 1997/Revised: 20 March 1998 相似文献
5.
Structural basis for the recruitment of ERCC1-XPF to nucleotide excision repair complexes by XPA 下载免费PDF全文
Tsodikov OV Ivanov D Orelli B Staresincic L Shoshani I Oberman R Schärer OD Wagner G Ellenberger T 《The EMBO journal》2007,26(22):4768-4776
The nucleotide excision repair (NER) pathway corrects DNA damage caused by sunlight, environmental mutagens and certain antitumor agents. This multistep DNA repair reaction operates by the sequential assembly of protein factors at sites of DNA damage. The efficient recognition of DNA damage and its repair are orchestrated by specific protein-protein and protein-DNA interactions within NER complexes. We have investigated an essential protein-protein interaction of the NER pathway, the binding of the XPA protein to the ERCC1 subunit of the repair endonuclease ERCC1-XPF. The structure of ERCC1 in complex with an XPA peptide shows that only a small region of XPA interacts with ERCC1 to form a stable complex exhibiting submicromolar binding affinity. However, this XPA peptide is a potent inhibitor of NER activity in a cell-free assay, blocking the excision of a cisplatin adduct from DNA. The structure of the peptide inhibitor bound to its target site reveals a binding interface that is amenable to the development of small molecule peptidomimetics that could be used to modulate NER repair activities in vivo. 相似文献
6.
Shoshani O Livne E Armoni M Shupak A Berger J Ramon Y Fodor L Gilhar A Peled IJ Ullmann Y 《Plastic and reconstructive surgery》2005,115(3):853-859
Adipose tissue injection as a free graft for the correction of soft-tissue defects is a widespread procedure in plastic surgery. The main problem in achieving long-term soft-tissue augmentation is partial absorption of the injected fat and hence the need for overcorrection and re-injection. The purpose of this study was to improve the viability of the injected fat by the use of interleukin-8. The rationale for the use of interleukin-8 was its abilities to accelerate angiogenesis and attract inflammatory cells and fibroblasts, providing the injected adipocytes more feeding vessels and a well-established graft bed to enhance their viability. Human adipose tissue, obtained by suction-assisted lipectomy, was re-injected into the subcutis in the scalp of nude mice. Interleukin-8 (0.25 ng) was injected subcutaneously to the scalp as a preparation of the recipient site 24 hours before the fat injection and was added to the fat graft itself (25 ng per 1 cc of injected fat). In the control group, pure fat without interleukin-8 was injected and no interleukin-8 was added for the preparation of the recipient site. One cubic centimeter of fat was injected in each animal in both the study and control groups. There were 10 animals in each group. The animals were euthanized 15 weeks after the procedure. Graft weight and volume were measured and histologic evaluation was performed. In addition, triglyceride content and adipose cell sizes were measured as parameters for fat cells viability. Histologic analysis demonstrated significantly less cyst formation in the group treated with interleukin-8. No significant differences were found between the groups with regard to graft weight and volume or the other histologic parameters investigated. No significant differences were demonstrated in adipose cell sizes and their triglyceride content. In conclusion, less cyst formation, indicating improved quality of the injected fat, can be obtained by the addition of interleukin-8. Further studies of various dosages of interleukin-8 and their long-term effect are required before these encouraging results could be applied clinically. 相似文献
7.
Impact of Admission and Cache Replacement Policies on Response Times of Jobs on Data Grids 总被引:1,自引:0,他引:1
Caching techniques have been used widely to improve the performance gaps of storage hierarchies in computing systems. Little
is known about the impact of policies on the response times of jobs that access and process very large files in data grids,
particularly when data and computations on the data have to be co-located on the same host. In data intensive applications
that access large data files over wide area network environment, such as data-grids, the combination of policies for job servicing
(or scheduling), caching and cache replacement can significantly impact the performance of grid jobs. We present preliminary
results of a simulation study that combines an admission policy with a cache replacement policy when servicing jobs submitted
to a storage resource manager.The results show that, in comparison to a first come first serve policy, the response times
of jobs are significantly improved, for practical limits of disk cache sizes, when the jobs that are back-logged to access
the same files are taken into consideration in scheduling the next file to be retrieved into the disk cache. Not only are
the response times of jobs improved, but also the metric measures for caching policies, such as the hit ratio and the average
cost per retrieval, are improved irrespective of the cache replacement policy used.
Ekow Otoo is research staff scientist with the scientific data management group at Lawrence Berkeley National Laboratory, University
of California, Berkeley. He received his B.Sc. degree in Electrical Engineering from the University of Science and Technology,
Kumasi, Ghana and a post graduate diploma in Computer Science from the University of Ghana, Legon. In 1977, he received his
M.Sc. degree in Computer Science from the University of Newcastle Upon Tyne in Britain and his Ph.D. degree in Computer Science
from McGill University, Montreal, Canada in 1983. He joined the faculty of the School of Computer Science, Carleton University,
in 1983 and from 1987 to 1999, he was a tenured faculty member of the School of Computer Science, Carleton University, Ottawa,
Canada. He has served as research consultant to Bell Northern Research, Ottawa, Canada, and as a research project consultant
to the GIS Division, Geomatics Canada, Natural Resources Canada, from 1990 to 1998. Ekow Otoo is a member of the ACM and IEEE.
His research interests include database management systems, data structures and algorithms, parallel I/O for high performance
computing, parallel and distributed computing.
Doron Rotem is currently a senior staff scientist and a member of the Data Management group at the Lawrence Berkeley National Lab. His
research interests include Grid Computing, Workflow, Scientific Data Management and Paralled and Distributed Computing and
Algorithms. He has published over 80 papers in international journals and conferences in these areas. Prior to that, Dr Rotem
co-founded and served as a CTO of a startup company, called CommerceRoute, that made software products in the area of workflow
and data integration and before that, he was an Associate Professor in the Department of Computer Science, University of Waterloo,
Canada. Dr. Rotem holds a B.Sc degree in Mathematics and Statistics from the Hebrew University, Jerusalem, Israel and a Ph.D.
in Computer Science from the University of the Witwatersrand, Johannesburg, South Africa.
Arie Shoshani is a senior staff scientist at Lawrence Berkeley National Laboratory. He joined LBNL in 1976. He heads the Scientific Data
Management Group. He received his Ph.D. from Princeton University in 1969. From 1969 to 1976, he was a researcher at System
Development Corporation, where he worked on the Network Control Program for the ARPAnet, distributed databases, database conversion,
and natural language interfaces to data management systems. His current areas of work include data models, query languages,
temporal data, statistical and scientific database management, storage management on tertiary storage, and grid storage middleware.
Arie is also the director of a Scientific Data Management (SDM) Integrated Software Infrastructure Center (ISIC), one of seven
centers selected by the SciDAC program at DOE in 2001. In this capacity, he is coordinating the work of collaborators from
4 DOE laboratories and 4 universities (see: http://sdmcenter.lbl.gov). Dr. Shoshani has published over 65 technical papers
in refereed journals and conferences, chaired several workshops, conferences, and panels in database management; and served
on numerous program committees for various database conferences. He also served as an associate editor for the ACM Transactions
on Database Systems. He was elected a member of the VLDB Endowment Board, served as the Publication Board Chairperson for
the VLDB Journal, and as the Vice-President of the VLDB Endowment. His home page is http://www.lbl.gov/arie. 相似文献
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Cereijido M Contreras RG Shoshani L Larre I 《American journal of physiology. Cell physiology》2012,302(3):C473-C481
Thanks to the homeostasis of the internal milieu, metazoan cells can enormously simplify their housekeeping efforts and engage instead in differentiation and multiple forms of organization (tissues, organs, systems) that enable them to produce an astonishing diversity of mammals. The stability of the internal milieu despite drastic variations of the external environment (air, fresh or seawater, gastrointestinal fluids, glomerular filtrate, bile) is due to transporting epithelia that can adjust their specific permeability to H(2)O, H(+), Na(+), K(+), Ca(2+), and Cl(-) over several orders of magnitude and exchange substances with the outer milieu with exquisite precision. This exchange is due to the polarized expression of membrane proteins, among them Na(+)-K(+)-ATPase, an oligomeric enzyme that uses chemical energy from ATP molecules to translocate ions across the plasma membrane of epithelial cells. Na(+)-K(+)-ATPase presents two types of asymmetries: the arrangement of its subunits, and its expression in one pole of the epithelial cell ("polarity"). In most epithelia, polarity consists of the expression of Na(+)-K(+)-ATPase towards the intercellular space and arises in part from the interaction of the extracellular segment of the β-subunit with another β-subunit present in a Na(+)-K(+)-ATPase molecule expressed by a neighboring cell. In addition to enabling the Na(+)-K(+)-ATPase to transport ions and water vectorially, this position exposes its receptors to ouabain and analogous cardiotonic steroids, which are present in the internal milieu because these were secreted by endocrine cells. 相似文献