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1.
Renata Dziedzic Manjot Kiran Przemyslaw Plocinski Malgorzata Ziolkiewicz Anna Brzostek Meredith Moomey Indumati S. Vadrevu Jaroslaw Dziadek Murty Madiraju Malini Rajagopalan 《PloS one》2010,5(7)
FtsZ assembly at the midcell division site in the form of a Z-ring is crucial for initiation of the cell division process in eubacteria. It is largely unknown how this process is regulated in the human pathogen Mycobacterium tuberculosis. Here we show that the expression of clpX was upregulated upon macrophage infection and exposure to cephalexin antibiotic, the conditions where FtsZ-ring assembly is delayed. Independently, we show using pull-down, solid-phase binding, bacterial two-hybrid and mycobacterial protein fragment complementation assays, that M. tuberculosis FtsZ interacts with ClpX, the substrate recognition domain of the ClpXP protease. Incubation of FtsZ with ClpX increased the critical concentration of GTP-dependent polymerization of FtsZ. Immunoblotting revealed that the intracellular ratio of ClpX to FtsZ in wild type M. tuberculosis is approximately 1∶2. Overproduction of ClpX increased cell length and modulated the localization of FtsZ at midcell sites; however, intracellular FtsZ levels were unaffected. A ClpX-CFP fusion protein localized to the cell poles and midcell sites and colocalized with the FtsZ-YFP protein. ClpX also interacted with FtsZ mutant proteins defective for binding to and hydrolyzing GTP and possibly for interactions with other proteins. Taken together, our results suggest that M. tuberculosis ClpX interacts stoichiometrically with FtsZ protomers, independent of its nucleotide-bound state and negatively regulates FtsZ activities, hence cell division. 相似文献
2.
Cytogenetics of the European plethodontid salamanders of the genus Hydromantes (Amphibia,Urodela) 总被引:1,自引:0,他引:1
A karyological analysis was carried out on different European species of the genus Hydromantes (Plethodontidae). All the species examined share the same chromosome number (2n=28) and, with the exception represented by pair XIV, morphologically similar karyotypes. While the karyotypes display a similar distribution — mainly centromeric and pericentric — of C-heterochromatin, quantitative variations in pericentric heterochromatin are observed among species. In the continental species Hydromantes italicus and ambrosii as well as in the eastern Sardinian species imperialis, flavus and specie nova, pair XIV consists of heteromorphic sex chromosomes of the XX/XY type. It is proposed that the differentiation of the Y might have taken place through the occurrence of a structural rearrangement, such as a pericentric inversion, starting from a hypothetical, homomorphic pair XIV. A sex-related heteromorphism is not found in the western Sardinian species H. genei. A further karyological differentiation among these species concerns the position of the nucleolus organizing region (NOR), which is located on chromosome XII (H. italicus and ambrosii) or on chromosome X, close to the centromere (H. genei, H. imperialis and H. specie nova), or in an intercalary position (H. flavus). The location and the number of the 5 S DNA sites have been conserved during species divergence. On the basis of these karyological data, as well as of results obtained through a preliminary restriction enzyme analysis of the ribosomal and genomic DNAs, the phyletic relationships among the European Hydromantes species are discussed. 相似文献
3.
The existence of six amylase heterogeneity variants in serum and urine has been discovered in a group of 111 families with twins, and the frequence of each variant was determined. It had been shown that each of these amylase heterogeneity variants is inherited codominantly, and the mode of inheritance is demonstrated schematically.These amylase heterogeneity variants may be used as an aid to twin zygosity determination and also in paternity problems. 相似文献
4.
Renata Novakova Jana Bistakova Dagmar Homerova Bronislava Rezuchova Lubica Feckova Jan Kormanec 《DNA sequence》2004,15(3):188-195
We cloned a new polyketide gene cluster, aur2, in Streptomyces aureofaciens CCM3239. Sequence analysis of the 9531-bp DNA fragment revealed 10 open reading frames, majority of which showed high similarity to the previously characterized type II polyketide synthase (PKS) genes. An unusual feature of the aur2 cluster is a disconnected organization of minimal PKS genes; ACP is located apart from the genes for ketosynthases KSalpha and KSbeta. The aur2 gene cluster was disrupted in S. aureofaciens CCM3239 by a homologous recombination, replacing the four genes (aur2A, E, F, G) including ketosynthase KSalpha, with antibiotic resistance marker gene. The disruption did not affect growth and differentiation, and disrupted strain produced spores with wild-type grey-pink pigmentation. The biochromatographic analysis of the culture extracts from S. aureofaciens wild type and aur2-disrupted strains did not reveal any difference in the pattern of antibacterial compounds. 相似文献
5.
R De Luca A Renzulli V Di Donna A Sicuranza C Sellitto P Mangano L Iovino 《Bollettino della Società italiana di biologia sperimentale》1984,60(4):739-744
In this research we have determined the behaviour of proteic plasmatic pattern and some enzymes during extracorporeal circulation and we noted a constant increase of albumin and of the ratio Alb/Glob. We observed also variations of some enzymes. Our opinion according other AA. is that this changes are determined principally by the large dose of heparin necessary during the C.E.C. 相似文献
6.
Renata Brelińska Prof. Dr. Christoph Pilgrim Ingrid Reisert 《Cell and tissue research》1984,236(3):661-667
Summary Male Wistar rats were injected intravenously with 5-(3H)uridine-labeled lymphocytes isolated from lymph nodes of syngeneic donors and enriched in T cells. After short periods of time (3 to 120 min after injection), labeled lymphocytes were localized in spleen compartments using autoradiography to identify routes of lymphocyte movement from blood into splenic parenchyma and to follow migration pathways of recirculating lymphocytes within the periarterial lymphoid sheath (PALS). Topographical analysis of labeled lymphocytes was performed in specific planes of PALS characterized by the diameter of the arterial vessel and termed PALS large, PALS medium, and PALS small (PALS L, PALS M, PALS S, respectively). Attention was also paid to accumulations of labeled lymphocytes close to the arterial vessel wall. Initially, labeled lymphocytes were localized in PALS S and PALS M near the terminal branching of arterial vessels and in the marginal zone (MZ). We conclude that lymphocytes emigrate from blood into splenic parenchyma within two white pulp compartments: in MZ, and directly within PALS through the wall of capillary vessels. The sequential accumulation of labeled cells near arterial vessels of increasing diameter suggests that the recirculating pool of lymphocytes migrates into the central part of PALS L by two routes: from MZ, and along arterial vessels from PALS S and PALS M.R.B. was a fellow of the Alexander von Humboldt-Stiftung, on leave from the Department of Histology and Embryology, Institut of Biostructure, Academy of Medicine, ul. Swiecickiego 6, PL-60-781 Pozna, Poland. 相似文献
7.
New data on the development of polarity in the ovules during megasporogenesis and early stages of embryo sac development inOenothera-hybrids are presented. It is confirmed that allOe. hookeri-hybrids show a strong tendency to form heteropolar tetrads, with the micropylar megaspore developing into an embryo sac. This preference is seen in the delay of the second meiotic division on the chalazal side, the absence of callose in the lateral wall of the micropylar megaspore, and the accumulation of starch in this megaspore. However, homopolar tetrads, chalazal preference, and ovules with two developing embryo sacs are also observed with considerable frequency. Quantitative data on the frequency of the different developmental types are compared with earlier genetic results about competition in the haplophase. There is sufficiently good agreement to support the hypothesis ofRenner that there is a correlation between the developmental processes in the megaspore tetrad and the genetic phenomena of competition in the haplophase. 相似文献
8.
F T Mangano T Fukuzawa W C Johnson J T Bagnara 《The Journal of experimental zoology》1992,263(1):112-118
Consistent with the concept that specific pigment patterns of amphibians might result from the highly localized distribution of stimulators and inhibitors of pigment cell expression in the skin, the spot pattern of the leopard frog, Rana pipiens, was examined through the use of the Xenopus neural tube explant assay system (Fukuzawa and Ide, 1988). Media conditioned with pieces of skin from dorsal black spotted areas promoted melanization of neural crest cells at a significantly higher level than did media conditioned with dorsal interspot skin in the absence of extra tyrosine. All conditioned media contained exceedingly low concentrations of tyrosine. With the addition of supplemental tyrosine, the melanization capacity of conditioned media from the interspot areas was elevated to that of the spotted skin. Control media conditioned with ventral frog skin inhibited melanization, as usual, because of the presumed presence of melanization inhibiting factor (MIF). It is considered that dorsal skin contains a melanization stimulating factor (MSF) which is present in significantly higher levels in spotted skin than in interspot areas and that expression of the particular pigmentary pattern of this leopard frog is regulated by the relative distribution of MIF, MSF, and possibly other intrinsic substances present in the skin. 相似文献
9.
Stephen D. M. Brown Philip Avner Verne M. Chapman Renata M. J. Hamvas Gail E. Herman 《Mammalian genome》1991,1(Z1):S318-S331
Overall, the probe map fromDXWas70 toAmg encompasses 72 cM and includes 103 loci. Eight of these have been designated reference loci (see Table 2 and previous section) on account of their wide usage that would enable the cross reference of independent maps created in different laboratories. Reference loci are to be readily available and easily used probes for Southern hybridization. By and large, they will be STSs, regeneratable by PCR, and correspond to a known gene. In addition, on the mouse X Chr, there is a reference locus from each of the known conserved linkage groups found between the mouse and human X Chrs. All the loci, barDXWas31, represent conserved sequences.
Committee Members: D. Adler, P.J. Barnard, Y. Boyd, N. Brockdorff, J. Derry, C. Disteche, C. Faust, M.F. Lyon, S. Rastan, M. Seldin and L. Siracusa. 相似文献
10.
Abstract A possible involvement of amino acid uptake mechanisms in the etiology of the human neurodegenerative disease, Huntington's disease (HD), was investigated. Measurement of glutamate (Glu) and aspartate (Asp) uptake was performed in blood platelets, which have previously been shown to constitute a peripheral model system for central amino acid uptake processes. Analyses of Glu and Asp accumulation at 10−7 M and kinetic examination of the high affinity site for Glu indicate no significant differences between control and HD platelets. A genetically determined defect in amino acid uptake therefore does not seem to underlie the nerve cell loss observed in HD patients. 相似文献