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11.
Heba A. Ahmed Eman H. S. Ibrahim Ekram Abdelhaliem Eman Y. T. Elariny 《Journal of applied microbiology》2022,132(6):4555-4568
The aim of this study was to investigate the frequency, molecular characterization, virulence genes, resistance genes and antimicrobial profile of nosocomial extended spectrum beta lactamase producing Klebsiella species. A total of 22 (12.2%) K. pneumoniae strains were isolated from 180 clinical samples collected from hospitalized patients in Egypt. K. pneumoniae biotypes were B1 (72.8%), B3 (13.6%) and B4 (13.6%). The isolates were classified for the capsular serotypes, 86.4% (20/22) were of K1 serotype, while only two isolates (13.64%) were of K2 serotype. Hypermucoviscous K. pneumoniae isolates accounted for 68.2%. Biofilm formation ability of K. pneumoniae was determined by microtitre plate method. The majority of the isolates (40.9%) were moderate biofilm producers, while 27.3% were strong biofilm producers. All K. pneumoniae strains were positive for fimH and traT genes, while magA was identified in only 63.6% of the isolates. The antibiotic susceptibility profile of the isolates (n = 22) was determined by the disc diffusion technique using 23 different antibiotics. Streptomycin and imipenem are the most effective antibiotics against 22 tested K. pneumoniae isolates with sensitivity rates of 63.64% and 54.54% respectively. All tested K. pneumoniae isolates showed high resistance to amoxicillin∕clavulanate (100%), cefuroxime (100%) and ceftazidime (95.45%). Extended spectrum beta lactamases (ESBL) production and the presence of ESBL-related genes were tested in the isolates. All the isolates tested positive for blaVIM, NDM1 and blaTEM, while only 81.8 %tested positive for the blaSHV gene. Increasing antimicrobial resistance in K. pneumoniae causing nosocomial infections limits the use of antimicrobial agents for treatment. Furthermore, the spread of biofilm, multiple drug resistant and ESBL-producing K. pneumoniae isolates is a public threat for hospitalized patients. 相似文献
12.
Overproduction of desired metabolites usually sacrifices cell growth. Here we report that quorum sensing (QS) can be exploited to coordinate cell growth and lactic acid production in Escherichia coli. We engineered two QS strains: one strain overexpressing acyl-homoserine lactone (AHL) synthesis genes (“ON”), the other strain overexpressing both AHL synthesis and degradation gene (aiiA) (“ON to semi-OFF”). To clarify the impact of the QS system on lactic acid production, D-lactate dehydrogenase gene ldhA was deleted from the E. coli genome, and Enhanced Green Fluorescence Protein (eGFP) was used as the reporter. Compared to the “ON” strain, the “ON to semi-OFF” strain showed delayed log growth and decreased egfp expression at stationary phase. When egfp was replaced by ldhA for lactic acid production, compared to the wild-type strain, the “ON to semi-OFF” strain demonstrated 231.9% and 117.3% increase in D-lactic acid titer and space-time yield, respectively, while the “ON” strain demonstrated 83.6%, 31%, and 36% increase in growth rate, maximum OD600, and glucose consumption rate, respectively. Quantitative real-time PCR revealed that both ldhA and the genes for phosphotransferase system were up-regulated in ldhA-overexpressing “ON” strain compared to the strain only harboring QS system. Moreover, the “ON” strain showed considerable increase in glucose consumption after a short lag phase. Compared to the reference strain harboring only ldhA gene in vector, both the “ON” and “ON to semi-OFF” strains demonstrated synchronization between cell growth and D-lactic acid production. Collectively, QS can be leveraged to coordinate microbial growth and product formation. 相似文献
13.
El-Beltagi Hossam S. Mohamed Heba I. Aldaej Mohammed I. Al-Khayri Jameel M. Rezk Adel A. Al-Mssallem Muneera Q. Sattar Muhammad N. Ramadan Khaled M. A. 《In vitro cellular & developmental biology. Plant》2022,58(4):615-629
In Vitro Cellular & Developmental Biology - Plant - Plants that produce bioactive chemicals provide a viable in vitro method for producing key nutraceutical substances, especially in the... 相似文献
14.
Alfredo Borie Diogo B. Hungria Heba Ali Carolina R. Doria Michael L. Fine Paulo E. Travassos 《Journal of fish biology》2019,95(3):820-832
Species-specific disturbance calls of five commercially-important characiform species are described, the Curimatidae commonly called branquinhas: Potamorhina latior, Potamorhina altamazonica and Psectrogaster amazonica; Prochilodontidae: jaraquí Semaprochilodus insignis and curimatã Prochilodus nigricans. All species have a two-chambered swimbladder and the sonic mechanism, present exclusively in males, utilises hypertrophied red muscles between ribs that adhere to the anterior chamber. The number of muscles is unusually plastic across species and varies from 1 to 4 pairs suggesting considerable evolution in an otherwise conservative system. Advertisement calls are produced in river confluences in the Madeira Basin during the high-water mating season (January–February). Disturbance calls and sampling allowed recognition of underwater advertisement choruses from P. latior, S. insignis and P. nigricans. The advertisement calls of the first two species have largely similar characteristics and they mate in partially overlapping areas in the Guaporé River. However, P. latior sounds have a lower dominant frequency and it prefers to call from river confluences whereas S. insignis shoals occur mostly in the main river channel adjacent to the confluence. These results help identify and differentiate underwater sounds and evaluate breeding areas during the courtship of commercially important characids likely to be affected by two hydroelectric dams. 相似文献
15.
Mamdouh M. Ghorab Heba M. Abdel-Salam Marwa A. El-Sayad Mohammed M. Mekhel 《AAPS PharmSciTech》2004,5(4):63-68
The purpose of this research was to evaluate β-cyclodextrin (β-CD) as a vehicle, either singly or in blends with lactose (spray-dried
or monohydrate), for preparing a meloxicam tablet. Aqueous solubility of meloxicam in presence of β-CD was investigated. The
tablets were prepared by direct compression and wet granulation techniques. The powder blends and the granules were evaluated
for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to
thickness, diameter, weight variation test, drug content, hardness, friability, disintegration time, and in vitro dissolution
studies. The effect of β-CD on the bioavailability of meloxicam was also investigated in human volunteers using a balanced
2-way crossover study. Phase-solubility studies indicated an AL-type diagram with inclusion complex of 1∶1 molar ratio. The powder blends and granules of all formulations showed satisfactory
flow properties, compressibility, and drug content. All tablet formations prepared by direct compression or wet granulation
showed acceptable mechanical properties. The dissolution rate of meloxicam was significantly enhanced by inclusion of β-CD
in the formulations up to 30%. The mean pharmacokinetic parameters (Cmax, Ke, and area under the curve [AUC]0−∞) were significantly increased in presence of β-CD. These results suggest that β-CD would facilitate the preparation of meloxicam
tablets with acceptable mechanical properties using the direct compression technique as there is no important difference between
tablets prepared by direct compression and those prepared by wet granulation. Also, β-CD is particularly useful for improving
the oral bioavailablity of meloxicam. 相似文献
16.
The purpose of this research was to evaluate beta-cyclodextrin (beta-CD) as a vehicle, either singly or in blends with lactose (spray-dried or monohydrate), for preparing a meloxicam tablet. Aqueous solubility of meloxicam in presence of beta-CD was investigated. The tablets were prepared by direct compression and wet granulation techniques. The powder blends and the granules were evaluated for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to thickness, diameter, weight variation test, drug content, hardness, friability, disintegration time, and in vitro dissolution studies. The effect of beta-CD on the bioavailability of meloxicam was also investigated in human volunteers using a balanced 2-way crossover study. Phase-solubility studies indicated an A(L)-type diagram with inclusion complex of 1:1 molar ratio. The powder blends and granules of all formulations showed satisfactory flow properties, compressibility, and drug content. All tablet formulations prepared by direct compression or wet granulation showed acceptable mechanical properties. The dissolution rate of meloxicam was significantly enhanced by inclusion of beta-CD in the formulations up to 30%. The mean pharmacokinetic parameters (C(max), K(e), and area under the curve [AUC](0-infinity)) were significantly increased in presence of beta-CD. These results suggest that beta-CD would facilitate the preparation of meloxicam tablets with acceptable mechanical properties using the direct compression technique as there is no important difference between tablets prepared by direct compression and those prepared by wet granulation. Also, beta-CD is particularly useful for improving the oral bioavailablity of meloxicam. 相似文献
17.
A tree-based algorithm for determining the effects of solvation on the structure of salivary gland tripeptide NH3+-D-PHE-D-GLU-GLY-COO-
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A D-enantiomeric analog of the submandibular gland rat-1 tripeptide FEG (Seq: NH(3)(+)-Phe-Glu-Gly-COO(-)) called feG (Seq: NH(3)(+)-D-Phe-D-Glu-Gly-COO(-)) was examined by molecular dynamics simulations in water. Previous in vacuo simulations suggested a conformation consisting predominantly of interactions between the Phe side chain and glutamyl-carboxyl group and a carboxyl/amino termini interaction. The solvated peptide was simulated using two approaches which were compared-a single 400-ns simulation and a "simulation tree." The "tree" approach utilized 45 10-ns simulations with different conformations used as initial structures for given trajectories. We demonstrate that multiple short duration simulations are able to describe the same conformational space as that described by longer simulations. Furthermore, previously described in vacuo interactions were confirmed with amendments: the previously described head-to-tail arrangement of the amino and carboxyl termini, was not observed; the interaction between the glutamyl carboxyl and Phe side chain describes only one of a continuum of conformations present wherein the aromatic residue remains in close proximity to the glutamyl carbonyl group, and also interacts with either of the two available carboxyl groups. Finally, utilizing only two separate 10-ns trajectories, we were able to better describe the conformational space than a single 60-ns trajectory, realizing a threefold decrease in the computational complexity of the problem. 相似文献
18.
Insertional Editing of Mitochondrial tRNAs of Physarum polycephalum and Didymium nigripes 总被引:1,自引:0,他引:1
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Travis Antes Heba Costandy Ratha Mahendran Matthew Spottswood Dennis Miller 《Molecular and cellular biology》1998,18(12):7521-7527
tRNAs encoded on the mitochondrial DNA of Physarum polycephalum and Didymium nigripes require insertional editing for their maturation. Editing consists of the specific insertion of a single cytidine or uridine relative to the mitochondrial DNA sequence encoding the tRNA. Editing sites are at 14 different locations in nine tRNAs. Cytidine insertion sites can be located in any of the four stems of the tRNA cloverleaf and usually create a G·C base pair. Uridine insertions have been identified in the T loop of tRNALys from Didymium and tRNAGlu from Physarum. In both tRNAs, the insertion creates the GUUC sequence, which is converted to GTΨC (Ψ = pseudouridine) in most tRNAs. This type of tRNA editing is different from other, previously described types of tRNA editing and resembles the mRNA and rRNA editing in Physarum and Didymium. Analogous tRNAs in Physarum and Didymium have editing sites at different locations, indicating that editing sites have been lost, gained, or both since the divergence of Physarum and Didymium. Although cDNAs derived from single tRNAs are generally fully edited, cDNAs derived from unprocessed polycistronic tRNA precursors often lack some of the editing site insertions. This enrichment of partially edited sequences in unprocessed tRNAs may indicate that editing is required for tRNA processing or at least that RNA editing occurs as an early event in tRNA synthesis. 相似文献
19.
Mahmoud El-Baz Younis Mohammed Naguib Abdel-Ghany Hasaneen Heba Mahmoud Mohammed Abdel-Aziz 《Plant signaling & behavior》2010,5(10):1197-1203
Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV radiation.Key words: Vicia faba, anthocyanins, phenolic compounds, total ascorbate, total glutathione, SOD, APO, CAT, GR 相似文献
20.
Yasar Nishat Mohammad Danish Heba I. Mohamed Hisamuddin Shaikh Abeer Elhakem 《Phyton》2022,91(8):1757-1777
Meloidogyne incognita is a plant pathogen causing root-knot disease and loss of crop yield. The present study
aimed to use Trichoderma harzianum as a biocontrol agent against plant-parasitic nematodes and used press
mud, which is a solid waste by-product of sugarcane, as a biocontrol agent and biofertilizer. Therefore, the combined application of T. harzianum and press mud may enhance nematode control and plant growth. Elemental
analysis of press mud using scanning electron microscopy (SEM) integrated with an Energy Dispersive X-ray
(EDX) analyzer revealed the presence of different elements such as C, O, Mg, Si, P, K, Ca, Cu and Zn. In addition,
a greenhouse study was conducted to investigate the combined effects of press mud and T. harzianum on M.
incognita reproduction and growth and the biochemical features of Psoralea corylifolia. The results showed that
plant length, dry biomass, leaf area, the number of seeds per plant, chlorophyll a, chl b, carotenoid content, nitrate
reductase, carbonic anhydrase, and nitrogen content were significantly increased (P ≤ 0.05) in the T2 plants
(plants were treated with 100 g of press mud + 50 mL T. harzianum before one week of M. incognita inoculation),
over inoculated plants (IC). Antioxidant enzyme activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in the foliage of P. corylifolia was significantly increased when
plants were treated with press mud + T. harzianum. A significant reduction in the number of egg masses, nematode population, and root-knot index (RKI) was found in plants with T2 plants. These results suggest that the
combined application of T. harzianum and press mud has the potential to control the M. incognita infection
and can be used as an environmentally safe alternative to chemical nematicides and also help in the removal
of sugarcane waste that causes environmental pollution. 相似文献