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81.
Abolghasem Tohidpour Shahin Najar Peerayeh Jalil F. Mehrabadi Hadi Rezaei Yazdi 《Current microbiology》2009,59(3):352-355
In Gram negative bacteria, fluoroquinolone resistance is acquired by target mutations in topoisomerase genes or by reducing
the permeation of drugs due to the increase in expression of endogenous multidrug efflux pumps that expel structurally unrelated
antimicrobial agents. An ongoing challenge is searching for new inhibitory substances in order to block efflux pumps and restore
the antibiotic drugs susceptibility. In this research, we sought to investigate the interplay between ciprofloxacin and an
efflux pump inhibitor (EPI), phenyl alanine arginyl β-naphtylamide (PAβN), to determine the prevalence of efflux pump overexpression
in clinical isolates of Pseudomonas aeruginosa. Ciprofloxacin was tested at different concentrations (256–0.25 μg/ml) with a fixed concentration of PAβN (50 μg/ml). The
isolates susceptibility profiles were analyzed by disc diffusion and agar dilution methods using 10 antibiotic discs and 4
powders. It was found that in the presence of PAβN, resistance to ciprofloxacin was inhibited obviously and MIC values were
decreased. The comparison between subgroups of P. aeruginosa isolates with different resistance profiles indicates that efflux pump overexpression (EPO) is present in 35% of ciprofloxacin
resistant isolates with no cross resistance and in variable frequencies among isolates showing cross resistance to other tested
antibiotics: gentamicin (31%), ceftazidime (29%), and imipenem (18%). Altogether, these results imply that PAβN maybe effective
to restore the fluoroquinolone drugs susceptibility in clinical treatment procedures. Results also show that increased use
of a fluoroquinolone drug such as ciprofloxacin can affect the susceptibility of P. aeruginosa to other different antipseudomonal agents. 相似文献
82.
Nigar Fatima Naseem Ahmad Mohammad Anis 《Journal of plant biochemistry and biotechnology.》2012,21(1):51-59
An efficient, rapid and reproducible plant regeneration protocol was successfully developed for Cuphea procumbens Orteg. using cotyledonary node explants excised from 15?days old aseptic seedlings. A range of cytokinins were investigated for multiple shoot regeneration. Of the three cytokinins, 6-benzyladenine (BA), Kinetin (Kin) and 2-isopentenyl adenine (2-iP) evaluated as supplement to Murashige and Skoog (MS) medium, BA at a concentration of 2.5???M was effective in inducing multiple shoots. The highest number of multiple shoots (9.33?±?0.60) and maximum average shoot length (4.16?±?0.44?cm) was standardized on MS medium supplemented with 2.5???M BA alongwith 0.5???M NAA. Addition of 200?mg/l Casein hydrolysate (CH) to the shoot induction medium enhanced the growth of regenerants. Rooting of in vitro regenerated shoots was best achieved on 1/2 strength MS medium. The in vitro raised plantlets with well developed shoots and roots were hardened, successfully established in earthen pots containing garden soil and maintained in greenhouse with 80% survival rate. Randomly Amplified Polymorphic DNA (RAPD) markers were used to evaluate the genetic stability among in vitro regenerated progenies. All RAPD profiles from the micropropagated plants were monomorphic and similar to control plant. These results suggests that the culture conditions used for the axillary bud proliferation are appropriate for clonal propagation of this medicinally important plant as they do not appear to interfere with genetic integrity of in vitro regenerated plants. The described method can be successfully employed for large-scale multiplication and in vitro conservation of C. procumbens. 相似文献
83.
Hadi Rezaei Yazdi Ghorban Behzadian Nejad Shahin Najar Peerayeh Mohammad Mostafaei 《Annals of microbiology》2007,57(2):293-295
Of the 126 isolates obtained from clinical specimens, seventy strains were selected because of resistance or reduced susceptibilities to imipenem and/or ceftazidime. Screening for detection of MBL-producing strains was performed in latter isolates by the Etest MBL strips. Isolates that were positive to Etest MBL strips were analysed by PCR. PCR was performed with specific DNA probes for detection of genes coding IMP or VIM enzymes and positive controls (MBL-producing strains). Finally, eight isolates ofPseudomonas aeruginosa were detected to carry a blaVIM gene. 相似文献
84.
Gayathri Bommakanti Xianghan Lu Michael P. Citron Tariq Ahmad Najar Gwendolyn J. Heidecker Jan ter Meulen Raghavan Varadarajan Xiaoping Liang 《Journal of virology》2012,86(24):13434-13444
The hemagglutinin protein (HA) on the surface of influenza virus is essential for viral entry into the host cells. The HA1 subunit of HA is also the primary target for neutralizing antibodies. The HA2 subunit is less exposed on the virion surface and more conserved than HA1. We have previously designed an HA2-based immunogen derived from the sequence of the H3N2 A/HK/68 virus. In the present study, we report the design of an HA2-based immunogen from the H1N1 subtype (PR/8/34). This immunogen (H1HA0HA6) and its circular permutant (H1HA6) were well folded and provided complete protection against homologous viral challenge. Antisera of immunized mice showed cross-reactivity with HA proteins of different strains and subtypes. Although no neutralization was observable in a conventional neutralization assay, sera of immunized guinea pigs competed with a broadly neutralizing antibody, CR6261, for binding to recombinant Viet/04 HA protein, suggesting that CR6261-like antibodies were elicited by the immunogens. Stem domain immunogens from a seasonal H1N1 strain (A/NC/20/99) and a recent pandemic strain (A/Cal/07/09) provided cross-protection against A/PR/8/34 viral challenge. HA2-containing stem domain immunogens therefore have the potential to provide subtype-specific protection. 相似文献
85.
Muhammad A Anis I Ali Z Awadelkarim S Khan A Khalid A Shah MR Galal M Khan IA Iqbal Choudhary M 《Bioorganic & medicinal chemistry letters》2012,22(1):610-612
A new methylene-bridged bisflavonoid, methylenebissantin (1), and nine known compounds, including flavonoids (2-5), diterpenoids (6 and 7), and phenol derivatives (8-10) were isolated from the aerial parts of Dodonaea viscosa Jacq. The structure elucidation was based on spectroscopic data analyses. The isolated compounds were evaluated for the inhibition of Plasmodium falciparum enoyl-ACP reductase (PfENR). Methylenebissantin (1) exhibited a moderate inhibition (IC(50) 91.13 μM) against PfENR. 相似文献
86.
An efficient protocol of direct somatic embryogenesis (without involving intermediate callus) has been developed from stem
segments and shoot tips of Capsicum annuum L. Explants were cultured on Murashige and Skoog (MS) medium supplemented with thidiazuron (TDZ). Among the various concentration
of TDZ tested, 0.5 μM was proved to be best for induction of somatic embryos. Induction, maturation and germination were achieved
on the same medium. The shoots developed from somatic embryos were transferred for rooting to MS medium supplemented with
indole-3-butyric acid (IBA). All the regenerated plants with 85 % survival rate were normal with respect to morphology and
growth characteristics. 相似文献
87.
Tobias A. Knoch Markus Göker Rudolf Lohner Anis Abuseiris Frank G. Grosveld 《European biophysics journal : EBJ》2009,38(6):757-779
The sequential organization of genomes, i.e. the relations between distant base pairs and regions within sequences, and its
connection to the three-dimensional organization of genomes is still a largely unresolved problem. Long-range power-law correlations
were found using correlation analysis on almost the entire observable scale of 132 completely sequenced chromosomes of 0.5 × 106 to 3.0 × 107 bp from Archaea, Bacteria, Arabidopsis thaliana, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Drosophila melanogaster, and Homo sapiens. The local correlation coefficients show a species-specific multi-scaling behaviour: close to random correlations on the
scale of a few base pairs, a first maximum from 40 to 3,400 bp (for Arabidopsis thaliana and Drosophila melanogaster divided in two submaxima), and often a region of one or more second maxima from 105 to 3 × 105 bp. Within this multi-scaling behaviour, an additional fine-structure is present and attributable to codon usage in all except
the human sequences, where it is related to nucleosomal binding. Computer-generated random sequences assuming a block organization
of genomes, the codon usage, and nucleosomal binding explain these results. Mutation by sequence reshuffling destroyed all
correlations. Thus, the stability of correlations seems to be evolutionarily tightly controlled and connected to the spatial
genome organization, especially on large scales. In summary, genomes show a complex sequential organization related closely
to their three-dimensional organization.
This article has been submitted as a contribution to the festschrift entitled “Uncovering cellular sub-structures by light
microscopy” in honor of Professor Cremer’s 65th birthday. 相似文献
88.
Ahmad Anees Anis Mohammad Khanam Mehrun Nisha Alatar Abdulrahman A. 《In vitro cellular & developmental biology. Plant》2020,56(5):670-681
In Vitro Cellular & Developmental Biology - Plant - An in vitro regeneration system for propagation of a valuable medicinal tree, Pterocarpus marsupium, using shoot tip (ST) explants derived... 相似文献
89.
Journal of Plant Growth Regulation - Meta-topolin (mT), a benzyladenine analog [N 6-(3-hydroxybenzylamino) purine] is a highly active cytokinin. The present study evaluates the efficiency of two... 相似文献
90.
Anis Y Nürnberg B Visochek L Reiss N Naor Z Cohen-Armon M 《The Journal of biological chemistry》1999,274(11):7431-7440
Evidence for depolarization-induced activation of G-proteins in membranes of rat brain synaptoneurosomes has been previously reported (Cohen-Armon, M., and Sokolovsky, M. (1991) J. Biol. Chem. 266, 2595-2605; Cohen-Armon, M., and Sokolovsky, M. (1993) J. Biol. Chem. 268, 9824-9838). In the present work we identify the activated G-proteins as Go-proteins by tracing their depolarization-induced in situ photoaffinity labeling with [alpha32P]GTP-azidoanilide (GTPAA). Labeled GTPAA was introduced into transiently permeabilized rat brain-stem synaptoneurosomes. The resealed synaptoneurosomes, while being UV-irradiated, were depolarized. Relative to synaptoneurosomes at resting potential, the covalent binding of [alpha32P]GTPAA to Galphao1- and Galphao3-proteins, but not to Galphao2- isoforms, was enhanced by 5- to 7-fold in depolarized synaptoneurosomes, thereby implying an accelerated exchange of GDP for [alpha32P]GTPAA. Their depolarization-induced photoaffinity labeling was independent of stimulation of Go-protein-coupled receptors and could be reversed by membrane repolarization, thus excluding induction by transmitters release. It was, however, dependent on depolarization-induced activation of the voltage-gated sodium channels (VGSC), regardless of Na+ current. The alpha subunit of VGSC was cross-linked and co-immunoprecipitated with Galphao-proteins in depolarized brain-stem and cortical synaptoneurosomes. VGSC alpha subunit most efficiently cross-linked with guanosine 5'-O-2-thiodiphosphate-bound rather than to guanosine 5'-O-(3-thiotriphosphate)-bound Galphao-proteins in isolated synaptoneurosomal membranes. These findings support a possible involvement of VGSC in depolarization-induced activation of Go-proteins. 相似文献