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Results 451 - 500 of 1333
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Olivares-Trejo José J - - 2003
To analyse the mechanism by which rare codons near the initiation codon inhibit cell growth and protein synthesis, we used the bacteriophage lambda int gene or early codon substitution derivatives. The lambda int gene has a high frequency of rare ATA, AGA and AGG codons; two of them (AGA AGG) ...
Lee Joong-Chul - - 2003
The mre genes of Escherichia coli and Bacillus subtilis are cell shape determination genes. Mutants affected in mre function are spheres instead of the normal rods. Although the mre determinants are not required for viability in E. coli, the mreB determinant is an essential gene in B. subtilis. Conflicting results ...
Fukuoka Hajime - - 2003
Escherichia coli can form linear trails and move in a flagellum-independent manner on semisolid agar containing carbon sources. Trail formation seemed to correlate with the growth speed and/or carbon metabolism. Cell morphology in linear trails changed into larger cell sizes. We speculate that the flagellum-independent trail formation is a new ...
Faraldo Ana Carolina - - 2003
The defense reactions against biological (Histoplasma capsulatum and Escherichia coli) and non-biological materials (China ink and nylon thread) were tested in vivo in third instar larvae of Dermatobia hominis. The cellular defense performed by larval hemocytes was observed under electron microscopy. China ink particles were phagocytosed by granular cells 5 ...
Verduzco-Luque Cynthia E - - 2003
A novel approach was developed for the construction of biofilms with defined internal architecture using AC electrokinetics and flocculation. Artificial structured microbial consortia (ASMC) consisting of localized layered microcolonies of different cell types were formed by sequentially attracting different cell types to high field regions near microelectrodes using dielectrophoresis. Stabilization ...
De Pedro Miguel A - - 2003
This paper extends, with computer techniques, the authors' previous work on the kinetics of pole wall and sidewall synthesis in Escherichia coli. These findings extend the conclusion that the nascent poles are made of entirely new material and that no new material is inserted into old poles. This requires re-evaluation ...
Kanouchi Hiroaki - - 2003
Because perchloric acid-soluble protein (PSP) has been conserved evolutionally in various species from Escherichia coli to humans, it may reflect an involvement in basic cellular regulation. However, the precise function of PSP is currently unknown. In this study, we examined the direct effect of PSP on the production of immunoglobulin ...
Willows Robert D - - 2003
The facultative photosynthetic bacterium Rhodobacter capsulatus can adapt from an anaerobic photosynthetic mode of growth to aerobic heterotrophic metabolism. As this adaptation occurs, the cells must rapidly halt bacteriochlorophyll synthesis to prevent phototoxic tetrapyrroles from accumulating, while still allowing heme synthesis to continue. A likely control point is Mg chelatase, ...
Suzuki Katsunori - - 2003
The agalpha1 mutant MAT alpha cells specifically lack the cell surface alpha-type sexual agglutination substance, which is also called alpha-agglutinin. Because the mutant cells (MATalpha agalpha1) can not form aggregates with MATa cells, MATalpha agalpha1 cells are unable to mate with MATa cells when they are co-inoculated in a liquid ...
Pferdeort Valerie A - - 2003
Through metabolic engineering, new enzymatic pathways can be introduced into cells to enable or enhance production or biotransformation of chemicals. However, these changes have physiological consequences that can be important but are not well understood. Here we describe the use of two-dimensional gel electrophoresis (2-DE) to detect changes in the ...
Bernhardt Thomas G TG Case Western Reserve University, School of Medicine, Department of Molecular Biology and Microbiology, W239, 10900 Euclid Ave., Cleveland, OH 44106, - - 2003
The N-acetylmuramoyl-l-alanine amidases of Escherichia coli (AmiA, B and C) are periplasmic enzymes that remove murein cross-links by cleaving the peptide moiety from N-acetylmuramic acid. Ami- cells form chains, indicating that the amidases help to split the septal murein. Interestingly, cells defective in the twin-arginine protein transport (Tat) pathway show ...
An Ke - - 2003
A cell regulatory sialoglycopeptide, CeReS-18, purified from intact bovine cerebral cortex cells, has exhibited the capability of reversibly inhibiting cellular DNA synthesis and the proliferation of a wide array of mammalian cells. In the present study, the effect of CeReS-18 on the proliferation of bacterial ( Bacillus cereus and Escherichia ...
Lawley Trevor D - - 2003
Plasmid R27 contains two independent partitioning modules, designated Par1 and Par2, within transfer region 2. Par1 is member of the type I partitioning family (Walker-type ATPase), and Par2 is a member of the type II partitioning family (actin-type ATPase). Stability tests of cloned Par1 and Par2 and insertional disruptions of ...
Pitt William G - - 2003
Ultrasound was employed to increase the growth rate of bacterial cells attached to surfaces. Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli cells adhered to and grew on a polyethylene surface in the presence of ultrasound. It was found that low-frequency ultrasound (70 kHz) of low acoustic intensity (<2 W/cm(2)) increased ...
Mao Hanbin - - 2003
We have developed a microfluidic assay for bacterial chemotaxis in which a gradient of chemoeffectors is established inside a microchannel via diffusion between parallel streams of liquid in laminar flow. The random motility and chemotactic responses to L-aspartate, L-serine, L-leucine, and Ni(2+) of WT and chemotactic-mutant strains of Escherichia coli ...
Schembri Mark A - - 2003
Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox sensor OxyR. Here we used mutant versions of OxyR ...
Nyström Thomas - - 2003
Like ageing insects, worms and mammals, growth-arrested Escherichia coli cells accumulate oxidatively damaged proteins. In the early stages of the E. coli stationary phase, this oxidation is caused by an increased production of aberrant proteins, which are especially susceptible to oxidative attack. This route of oxidation appears to elude the ...
Gohda Jin - - 2003
Homologues of the Escherichia coli (E. coli) Ras-like protein (ERA), a GTP-binding protein with RNA binding activity, have recently been found in various species, including human, mouse, and Antirrhinum majus. Depletion of prokaryotic ERA blocks cell division without affecting chromosome segregation. However, the physiological function of eukaryotic ERA is largely ...
Schilling Joel D - - 2003
The gram-negative bacterium Escherichia coli is the leading cause of urinary tract infection. The interaction between type 1 piliated E. coli and bladder epithelial cells leads to the rapid production of inflammatory mediators, such as interleukin-6 (IL-6) and IL-8. Conflicting reports have been published in the literature regarding the mechanism ...
Nyström Thomas - - 2003
Upon starvation and growth arrest, Escherichia coli cells gradually lose their ability to reproduce. These apparently sterile/nonculturable cells initially remain intact and metabolically active and the underlying molecular mechanism behind this sterility is something of an enigma in bacteriology. Three different models have been proposed to explain this phenomenon. The ...
Arfvidsson Cecilia - - 2003
The evaluation of the translation capacity of cells that produce recombinant proteins can be made by monitoring their ribosomal composition. In a previous use of asymmetrical flow field-flow fractionation (AsFlFFF) for this purpose the overall analysis time was more than 1 h and 40 min, based on a standard protocol ...
Jeong Ki Jun - - 2003
During growth of high-cell-density cultures of Escherichia coli, overproduction of recombinant proteins often results in increased stress response, cell filamentation, and growth cessation. Filamentation of cells consequently lowers final achievable cell concentration and productivity of the target protein. Reported here is a methodology that should prove useful for the enhancement ...
Makinoshima Hideki - - 2003
Escherichia coli cultures can be fractionated into more than 20 cell populations, each having a different bouyant density and apparently representing a specific stage of cell differentiation from exponential growth to stationary phase (H. Makinoshima, A. Nishimura, and A. Ishihama, Mol. Microbiol. 43:269-279, 2002). The density increase was found to ...
de Pedro Miguel A - - 2003
Some strains of Escherichia coli defective for dacA, the gene coding for penicillin-binding protein 5, exhibit a strong branching phenotype when cell division is blocked. Since such branch formation implies a differentiation of polar caps at ectopic locations in the cell envelope, we analyzed murein segregation and observed a strong ...
Pecota Douglas C - - 2003
The 52 amino acid host killing peptide (Hok) from the hok/sok post-segregational killer system of the Escherichia coli plasmid R1 was synthesized using Fmoc (9-fluorenylmethoxycarbonyl) chemistry, and its molecular weight was confirmed by mass spectroscopy. Hok kills cells by depolarizing the cytoplasmic membrane when it is made in the cytosol. ...
García D - - 2003
AIMS: The objective was to investigate the occurrence of sublethal injury in Escherichia coli by pulsed electric fields (PEF) at different pH values. METHODS AND RESULTS: The occurrence of sublethal injury in PEF-treated E. coli cells depended on the pH of the treatment medium. Whereas a slight sublethal injury was ...
Ryu J-H - - 2003
AIMS: The aim of this study was to optimize conditions to separate extracellular carbohydrate complexes (ECC) produced by Escherichia coli O157:H7 and to standardize the amount of ECC produced on a per cell basis. METHODS AND RESULTS: ECC fraction I was removed from E. coli O157:H7 cells produced on tryptic ...
Mattick Karen L - - 2003
Certain rod-shaped bacteria have been reported to form elongated filamentous cells when exposed to marginal growth conditions, including refrigeration temperatures. To expand upon these observations, the filamentation of commensal Escherichia coli, E. coli O157:H7 and Salmonella spp was investigated, following exposure to certain, mildly stressing, levels of temperature, pH or ...
Den Blaauwen Tanneke - - 2003
The localization of penicillin-binding protein 2 (PBP2) in Escherichia coli has been studied using a functional green fluorescent protein (GFP)-PBP2 fusion protein. PBP2 localized in the bacterial envelope in a spot-like pattern and also at mid-cell during cell division. PBP2 disappeared from mid-cell just before separation of the two daughter ...
Yu Huimin - - 2003
Poly(beta-hydroxybutyrate) (PHB) production using a recombinant Escherichia coli VG1 (pTU14) was carried out. PHB granules were gradually biosynthesized in recombinant cells as inclusion bodies and the morphology of cells became linearly inflated with PHB accumulation from 6 h to 36 h of culture. The stability of plasmid pTU14 was inevitably ...
Samartzidou Hrissi - - 2003
When grown at acidic pH, Escherichia coli cells secrete cadaverine, a polyamine known to inhibit porin-mediated outer membrane permeability. In order to understand the physiological significance of cadaverine excretion and the inhibition of porins, we isolated an OmpC mutant that showed resistance to spermine during growth and polyamine-resistant porin-mediated fluxes. ...
Tan Xingzhi - - 2002
Comparative mutagenesis studies of N-(2'-deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-AAF) and N-(2'-deoxyguanosin-8-yl)-2-aminofluorene (dG-AF) adducts positioned in the Nar I restriction enzyme site were performed using Escherichia coli (E. coli) and simian kidney (COS-7) cells. Oligodeoxynucleotides ((5)(')TCCTCG(1)G(2)CG(3)CCTCTC) containing a recognition sequence for the Nar I restriction enzyme were modified site-specifically with dG-AAF or dG-AF. Modified ...
Laestadius Asa - - 2002
BACKGROUND: alpha-Hemolysin (HlyA) producing Escherichia coli is a common cause of pyelonephritis and subsequent renal scarring. Recent studies have suggested that toxin secreted from HlyA E. coli may not only have a lytic effect, but also may activate a calcium signaling pathway in renal tubule cells. A dose dependent study ...
Held Michael - - 2002
An automated flow-injection system with an integrated biosensor array using bacterial cells for the selective and simultaneous determination various mono- and disaccharides is described. The selectivity of the individually addressable sensors of the array was achieved by the combination of the metabolic response, measured as the O(2) consumption, of bacterial ...
Iwai Noritaka - - 2002
Random screening for inhibitors of chromosome partitioning in Escherichia coli was done by the anucleate cell blue assay. A novel S-benzylisothiourea derivative, S-(3,4-dichlorobenzyl)isothiourea, tentatively named A22, was found to induce spherical cells and spherical anucleate cells in E. coli. Mecillinam, a specific inhibitor of penicillin-binding protein 2, which induces spherical ...
Ilegems Erwin - - 2002
A reporter assay was developed to detect and quantify nonsense codon suppression by chemically aminoacylated tRNAs in mammalian cells. It is based on the cellular expression of the enhanced green fluorescent protein (EGFP) as a reporter for the site-specific amino acid incorporation in its sequence using an orthogonal suppressor tRNA ...
Samuel Raj V - - 2002
In a speG-disrupted Escherichia coli mutant, which cannot metabolize spermidine to acetylspermidine, addition of spermidine to the medium caused a decrease in cell viability at the late stationary phase of growth. There were parallel decreases in the levels of ribosome modulation factor (RMF), the sigma(38) subunit of RNA polymerase, and ...
Arana I - - 2003
We have used an Escherichia coli strain DH5a containing pGreenTIR to study the survival of this bacterium in river water. As green fluorescence was maintained throughout survival both in dark and illuminated conditions, gfp-tagged E. coli cells were clearly distinguished from the microbial community of the river Butrón. gfp-tagged E. ...
Ramchuran S O - - 2002
Metabolic stress is a phenomenon often discussed in conjunction with recombinant protein production in Escherichia coli. This investigation shows how heterologous protein production and the presence of host cell proteases is related to: (1) Isopropyl-beta- D-thiogalactopyranoside (IPTG) induction, (2) cell-mass concentration at the time of induction, and (3) the presence ...
Cosper Michele Mader - - 2002
EPR and Mössbauer spectroscopies have been used to determine the type and properties of the iron-sulfur clusters present in homologously expressed recombinant Escherichia coli BioB in whole cells prior to purification. Difference EPR spectra of samples of whole cells from a strain over-expressing E. coli BioB and a strain containing ...
Soriano Elena - - 2002
Overexpression of recombinant proteins in Escherichia coli often leads to a severe growth retardation of the host cells. The phage T7 promoter phi10 in a pET vector was utilized to express human superoxide dismutase. Induction with IPTG lead to an increase in protein content and cell size and a termination ...
Akerlund Thomas - - 2002
The Min system of Escherichia coli directs cell division to the mid-cell by a mechanism that involves the dynamic localization of all of its three constituent proteins, MinC, MinD and MinE. Both the Min system and the nucleoid regulate cell division negatively and strains of E. coli lacking a functional ...
Nishihara Tohru - - 2002
Transmission electron micrographs of Escherichia coli cells induced by cloned lysis genes from RNA bacteriophages GA (group A-II) and SP (group B-IV) revealed various morphological aspects of intermediates of lysing cells. Cells induced by the SP lysis gene became stretched and also tapered in shape and fragmentation of parts of ...
Campbell Tracey L - - 2002
The ispF gene product in Escherichia coli has been shown to catalyze the formation of 2-C-methyl-D-erythritol 2,4-cyclodiphosphate (MEC) in the deoxyxylulose (DOXP) pathway for isoprenoid biosynthesis. In this work, the E. coli gene ispF and its Bacillus subtilis orthologue, yacN, were deleted and conditionally complemented by expression of these genes ...
Dhawan Mohit D - - 2002
A novel cell lysis system was developed that is based on laser-induced disruption of bacterial and yeast cells. It will find application as a rapid, efficient and clean sample preparation step in bioanalytical detection systems. Using E. coli as our model analyte, we optimized cell lysis with respect to optimal ...
Santos Jorge M - - 2002
The gene bolA has been shown to trigger the formation of osmotically stable round cells when overexpressed in stationary phase. We show that in poor growth conditions bolA is essential for normal cell morphology in stationary phase and under conditions of starvation. During exponential growth bolA promotes round morphology through ...
Miqdady Mohamad S - - 2002
Formalin-stored HEp-2 cells were used to assay Escherichia coli for adherence. Cells refrigerated in formalin for up to 28 days and used in a wet assay format demonstrated an assay sensitivity ranging from 94 to 98% to detect enteroaggregative E. coli (EAEC). HEp-2 cells first fixed and stored with formalin ...
Stone G - - 2002
We have developed a method for visualizing Escherichia coli cells that are exposed to tetracycline in a biofilm, based on a previous report that liposomes containing the E. coli TetR(B) protein fluoresce when exposed to this antibiotic. By our method, cells devoid of TetR(B) also exhibited tetracycline-dependent fluorescence. At 50 ...
Koebmann Brian J - - 2002
The nature of the control of glycolytic flux is one of the central, as-yet-uncharacterized issues in cellular metabolism. We developed a molecular genetic tool that specifically induces ATP hydrolysis in living cells without interfering with other aspects of metabolism. Genes encoding the F(1) part of the membrane-bound (F(1)F(0)) H(+)-ATP synthase ...
Shen Wei-Chiang - - 2002
Cryptococcus neoformans is a pathogenic fungus with a defined sexual cycle involving haploid MATalpha and MATa cells. Interestingly, MATalpha strains are more common, are more virulent than congenic MATa strains, and undergo haploid fruiting in response to nitrogen limitation or MATa cells. Three genes encoding the MFalpha pheromone were identified ...
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