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At least 451 records · Page 25Linked to original sources
PubMed1988

Characterization of plasma membranes from A431 cells, isolated by self-generating Percoll gradient: a rapid isolation procedure to obtain plasma membranes with functional epidermal growth factor receptors.

Plasma membranes have been isolated from the human epidermoid carcinoma cell line A431 by a rapid fractionation of lysate on Percoll density gradient at pH 9.6. Endoplasmic reticulum, lysosomes and mitochondria sedimented at the bottom of gradient whereas plasma membranes focused at low density, as shown with specific markers. Plasma membranes displayed a 4.5- and 4.4-fold enrichment in [3H]concanavalin A and 5'-nucleotidase, respectively. This proteic fraction was further characterized by its lipid composition and phospholipid analysis. The cholesterol/phospholipid molar ratio was 0.45 in plasma membranes against 0.19 in lysate. Sphingomyelin increased from 7.5% of total phospholipids in lysate to 16.2% in plasma membranes, as well as phosphatidylserine which displayed a 1.5-fold enrichment in the plasma membrane fraction. This was at the expense of phosphatidylcholine (45.2% in lysate, against 35% in plasma membranes). Electron microscopy of the isolated material showed vesicles essentially free from endoplasmic reticulum and organelles. These plasma membranes retained the ability to bind 125I-labelled epidermal growth factor (125I-EGF) with a Kd = 4.7 nM and Bmax = 63 pmol/mg protein. EGF binding resulted in a stimulation of the phosphorylation protein reaction in the presence of [gamma-32P]ATP and sodium dodecyl sulfate polyacrylamide gels of phosphorylated proteins indicated that the radioactivity of the major band of molecular weight 170,000 was clearly enhanced by EGF binding. These results indicate that the EGF receptor and its intrinsic protein kinase activity were preserved during our plasma membrane isolation procedure.

Carcinoma, Squamous Cell↗
PubMed1990

Metabolism of fatty acids and their incorporation into phospholipids of the mitochondria and endoplasmic reticulum in isolated hepatocytes determined by isolation of fluorescence derivatives.

Isolated hepatocytes were incubated in the presence of [14C]palmitic, [14C]linoleic or [14C]linolenic acid and the time-courses of incorporation of radioactivity into phosphatidylcholine and phosphatidylethanolamine of microsomes and mitochondria were followed. For this purpose a procedure was developed for HPLC separation of 9-diazomethylanthracene (ADAM) derivatives of fatty acids. When [14C]palmitic acid was used, the major product of elongation and desaturation was octadecadienoic acid, which accounted for 35-65% of the total radioactivity. Labeled palmitoleic, stearic and oleic acids could also be isolated. In fatty acids which do not participate to any large extent in deacylation-reacylation reactions, the pattern of incorporation was characteristic: a high rate of incorporation into microsomal and a low rate of incorporation into mitochondrial phospholipids during the first 40 min, followed by a decrease in the former and an increase in mitochondrial labeling. This pattern is consistent with the fact that de novo synthesis of these two phospholipids occurs in the endoplasmic reticulum in vivo. When cells were incubated in the presence of [14C]linoleic acid, 70-90% of the radioactivity recovered in phospholipids was in this same form, whereas the remaining label was mainly in arachidonic acid and, to some extent, in eicosatrienoic acid. When hepatocytes were incubated in the presence of [14C]linolenic acid, 70-85% of the radioactivity in isolated phospholipids was associated with linolenic acid. As much as 20% of the label was recovered in docosahexanoic acid and 5-10% in arachidonic acid. In the case of the two latter labeled substrates the exchange reactions seem to dominate over de novo synthesis. For phospholipids synthesized de novo the transfer from the endoplasmic reticulum to mitochondria requires about 3 h.

Animals↗
PubMed1977

Isolation of vitamin B-12-binding proteins by combined immuno and affinity chromatography. Comparative studies on the isolated and unisolated proteins.

Intrinsic factor or cobalophilin were removed by incubating human gastric juice and pig pyloric extract with purified anti-intrinsic factor and anti-cobalophilin immunoglobulin-G, respectively, covalently coupled to Sepharose. Cobalophilin (transcobalamin I) was also removed from pig serum either by using anti-cobalophilin immunoglobulin-G Sepharose or by Sephadex G-200 chromatography. The one remaining semipurified vitamin B-12-binding protein (intrinsic factor, cobalophilin or transcobalamin II) was then isolated by vitamin B-12-Sepharose affinity chromatography. Intrinsic factors, cobalophilins and transcobalamin II isolated by this two-step procedure were compared by double isotope techniques with the corresponding protein not subjected to affinity chromatography and found to be identical in reaction to antiserum, gel filtration and electrofocusing. The avidity of the isolated and unisolated intrinsic factors for the ileal intrinsic factor receptor was also the same.

Animals↗
PubMedDate not supplied

Isolation of Trypanosoma brucei gambiense from northern Uganda: evaluation of the kit for in vitro isolation (KIVI) in an epidemic focus.

867 individuals from 3 sites near the town of Adjumani in the East Moyo region of north-west Uganda were investigated clinically and serologically for evidence of current trypanosome infections. Blood samples were taken from 94 persons with a positive card agglutination test for trypanosomiasis (CATT) and clinical suspects and inoculated into the kit for in vitro isolation of Trypanosoma brucei gambiense (KIVI). Amongst this group, 30 parasitaemic individuals were identified by microhaematocrit centrifugation and the quantitative buffy coat technique (QBC). Only 80% of these isolates, and one isolate from an aparasitaemic individual, grew in culture. The success or failure of cultures from parasitaemic patients was unrelated to the size of the trypanosome inoculum. The implications of these results and possible reasons for the failure of KIVI are discussed.

Animals↗
PubMed1991

First field isolation of wound tumor virus from a plant host: minimal sequence divergence from the type strain isolated from an insect vector.

A new strain of wound tumor virus (WTV) has been isolated from a periwinkle plant (Catharanthus roseus) that was among several used as bait plants in a blueberry field. The 12 segments of double-stranded RNA of the viral genome were isolated directly from infected tissue and found to have mobilities through agarose gels that were identical to those of the type strain WTV. Coupled complementary DNA (cDNA) and polymerase chain reactions (PCR) primed with oligonucleotides complementary to the termini of segments 4-12 of the type strain of WTV successfully amplified those segments. Amplification products of the 9 segments were of the size expected for the full-length segment, with no shorter than full-length products representing defective RNAs detected. PCR products representing segments 7, 11, and 12 were cloned and sequenced in their entirety. The sequence of each segment varied only slightly from the homologous segment of the type strain. Variation ranged from less than 1% for segment 12 to approximately 3% for segment 7, but even these low levels of variation were much greater than the variation found in WTV isolates maintained in the laboratory. Most of the variation in each of the three segments was confined to the coding regions, and most of the differences were third position transitions. The new WTV strain has been designated WTVNJ.

Amino Acid Sequence↗
PubMed1987

The isolation of influenza virus from chickens in Israel and studies on its antigenic relationships with other native isolates of the same antigenicity by means of monoclonal antibodies.

A hemagglutinating (HA) agent isolated from an outbreak of a respiratory disease in a kibbutz broiler farm was identified as influenza virus A/chicken/Degania, Israel/80(H7N2). Investigation using a panel of 5 monoclonal antibodies against H7 antigenic subtype has shown substantial difference of the isolate from the other H7-containing influenza viruses isolated in Israel. Antigenic relationships between the native H7-containing strains revealed by means of the monoclonal antibodies led to re-evaluation of the suggested views on local epizootiology and interspecies transfer of avian influenza.

Animals↗
PubMed1990

Giardia isolates from primates and rodents display the same molecular polymorphism as human isolates.

Five Giardia isolates from primates and rodents were grown axenically and compared by different electrophoretic techniques. One isolate from a lemur (slow loris) contained a dsRNA virus also found in some of the Giardia of human origin. Using ethidium bromide stained gels and also Southern blots hybridized with a rDNA probe, two profiles of restriction fragment length polymorphism were found in the animal Giardia, which are identical to two profiles found previously in strains of human origin. Isoenzyme and total protein patterns obtained with agarose isoelectric focusing divided the strains in the same two groups. With pulsed field gradient gel electrophoresis, the isolates showed 6-8 chromosomal bands but none of the band patterns were identical. The size of the chromosomes varied from 0.8 to over 3.0 Mb. A ribosomal DNA probe hybridized with different bands.

Acid Phosphatase↗
PubMed1986

A comparison of strains of Serratia marcescens isolated from neonates with strains isolated from sporadic and epidemic infections in adults.

As a result of the increased number of outbreaks of Serratia marcescens in special care baby units in the UK, a study was undertaken to compare strains isolated from outbreaks of neonatal infection with strains isolated from outbreaks of infections in adults and with isolates from sporadic infections. None of the biochemical, serological, bacteriological markers examined could distinguish the three groups of strains. When considered as groups there was no difference in the ability of the strains to survive desiccation on hands. Strains from neonatal and sporadic infections were more sensitive to antibiotics than adult epidemic strains. The feature common to all of the neonatal strains tested was the ability to agglutinate one or more species of erythrocytes in the presence of mannose. Only one strain in each of the other two groups possessed mannose resistant haemagglutinins.

Adult↗
PubMed1981

Comparison of the rate of aminoacylation of tRNA isolated from NMRI mouse liver with tRNA isolated from Krebs II ascites or mouse plasmacytoma cells.

A comparison of the initial rates of aminoacylation of tRNAs isolated from different sources for 17 amino acids was performed. tRNA was isolated from NMRI mouse liver (tRNA L) and from Krebs II ascites tumors (tRNA Asc), and aminoacyl-tRNA synthetases were prepared from the latter cells. The aminoacylation of tRNA Asc was 31-88% slower than the charging of tRNA L. In similar studies, tRNA from a mouse plasmacytoma tumor (tRNA Mt) and from suspension cultured cells of the same cell line (tRNA M) were compared to tRNA L in the aminoacylation reaction catalysed by synthetases isolated from tumor or suspension cultured cells. About half of the tRNAs (Mt or M) for the 17 amino acids tested differed in charging rate when compared to tRNA L, but the differences were not as great as those observed in the experiments where tRNA Asc and tRNA L were compared.

Amino Acyl-tRNA Synthetases↗
PubMed1992

Two variants of transferrable extended-spectrum TEM-beta-lactamase successively isolated from a clinical Escherichia coli isolate.

In a leukaemic patient presenting a septicaemia treated with ceftazidime and amikacin, two clinical Escherichia coli isolates distinguished by their level of resistance to oxyimino-beta-lactams were isolated at an interval of 24 h. The isolates were identified by biotyping and esterase electrophoretic typing and the two host strains were shown to be identical. However, each of these strains exhibited a different transferrable extended-spectrum beta-lactamase. These enzymes had different pI values (5.25 and 5.58), but were both blaTEM-1 mutants. The enzyme with pI 5.25 was identical to TEM-101 (TEM-12) (serine 162 substitution). The enzyme with pI 5.58 showed an additional amino acid substitution (lysine residue instead of an arginine at position 237) and was denominated TEM-23. These data indicate that point-mutations can be successively cumulated in vivo by blaTEM mutants, leading to expression of beta-lactamases with increased hydrolysis rates.

Bacterial Typing Techniques↗
PubMed1988

Isolation of osteoclasts from Pagetic bone tissue: morphometry and cytochemistry on isolated cells.

Giant osteoclasts and other cells were isolated from Pagetic bone tissue using 0.5 mM ethylene diamine tetraacetic acid on bone samples from 8 patients with Paget's disease. The cell suspension contained osteoclasts and osteoblasts as well as some mononuclear cells such as monocytes. The number of nuclei in isolated osteoclasts (33.85 +/- 20.92 nuclei/osteoclast) correlates fairly well (p less than 0.02) with the number of nuclei counted on histologic sections (15.88 +/- 11.80 nuclei/osteoclast) for samples from each patient. Enzyme histochemistry demonstrated acid phosphatase activity in isolated osteoclasts and in mononucleated cells, such as monocytes. Alkaline phosphatase was detected only in osteoblasts while succinate dehydrogenase was observed in osteoclasts, osteoblasts and monocytes. Esterases, such as nonspecific aliesterase and specific naphthol AS-D acetate esterase, were identified in osteoclasts and in macrophages. Inhibition of specific naphthol AS-D acetate esterase in osteoclasts by addition of sodium fluoride suggests that the enzyme could be of monocytic origin.

Esterases↗
PubMed2004

Prevalence of isolated systolic and isolated diastolic hypertension subtypes in China.

BACKGROUND: Isolated systolic hypertension (ISH), more so than any other hypertension subtype, increases the risk for stroke and coronary heart disease. The prevalence of ISH versus other hypertension subtypes in the general Chinese adult population is not known. METHODS: The prevalence of isolated systolic and isolated diastolic hypertension (IDH) was examined in a representative national sample of 15,540 Chinese adults aged 35 to 74 years. Three seated blood pressure (BP) measurements taken after 5 min of rest were averaged and hypertension subtypes were defined among individuals not receiving antihypertensive therapy as follows: ISH as systolic BP >/=140 mm Hg and diastolic BP <90 mm Hg; IDH as systolic BP <140 mm Hg and diastolic BP >/=90 mm Hg; and combined systolic/diastolic hypertension (SDH) as a systolic BP >/=140 mm Hg and diastolic BP >/=90 mm Hg. RESULTS: Overall, 7.6% of the Chinese adult population had ISH, 7.4% had SDH, and 4.4% had IDH. The prevalence of ISH increased with age and was more common in older women than in older men. Stage 1 hypertension was much more prevalent than stage 2 hypertension among all hypertension subtypes. The prevalence of SDH, IDH, and ISH (women, only) were higher in northern China than southern. The prevalence of ISH and SDH (women, only) were higher among rural residents versus urban residents. CONCLUSIONS: These data document high rates of ISH in China. Given the risk of cardiovascular disease associated with ISH, our findings underscore the critical need for enhanced hypertension screening and treatment programs in China.

Adult↗
PubMed2004

Isolation and sequencing of the replication region of plasmid pBFp1 isolated from a marine biofilm.

A 24 kb plasmid, pBFp1, encoding mercury resistance was previously isolated from a marine biofilm. Isolation and sequencing of a 4280 bp DNA fragment containing the plasmid replicon (rep-pBFp1) revealed a putative open reading frame encoding a RepA protein and an oriV-like region containing an A+T rich sub-region, iterons, and DnaA boxes. Sequence comparisons showed significant similarities to the incW plasmid pSa both for the RepA amino acid sequence and in the iteron DNA sequence. Plasmid pBFp1 was also shown to be incompatible with pSa in standard incompatibility testing. A probe from the repA gene of pBFp1 was further made and tested on a collection of plasmids exogenously isolated from marine habitats in a previous study.

Amino Acid Sequence↗
PubMed2005

A high proportion of Baltic Sea benthic cyanobacterial isolates contain apoptogens able to induce rapid death of isolated rat hepatocytes.

To assess the potential hepatotoxicity of benthic cyanobacteria, we isolated 41 strains from the Baltic Sea. The bacteria were differentially extracted with solvents of decreasing polarity. The extracts were tested for ability to induce death of primary rat hepatocytes in suspension culture. Mainly morphological criteria were used to discriminate between cell death with apoptotic features (shrinkage, chromatin hypercondensation, budding) or necrotic features (swelling, loss of plasma membrane integrity). The 24 isolates containing hepatotoxic compounds were of the genus Anabaena. The non-toxic isolates were mainly Nostoc and Calothrix. The toxicity was not due to the known hepatotoxic cyanobacterial protein phosphatase inhibitors microcystin or nodularin, as demonstrated by lacking competition with microcystin for PP2A binding. Apoptotic cell death was rapid, being evident from 10 to 60 min after the addition of extract. Sometimes the initial apoptosis was followed by secondary necrosis. Three cyanobacterial extracts produced apoptosis with unusual cell morphology including actin rearrangements. It will be of interest to know if they contain substance(s) acting through novel death pathways. We conclude that benthic Anabaena cyanobacteria represent a rich source of apoptogenic toxins, presumably directed against competitors or predators in the aquatic environment, but obviously able also to induce cell death in mammalian parenchymal liver cells.

Actins↗
PubMed2005

Isolates of Pneumocystis jirovecii from Harare show high genotypic similarity to isolates from London at the superoxide dismutase locus.

Pneumocystis jirovecii is the cause of Pneumocystis pneumonia (PCP) in humans. Isolates of P. jirovecii obtained from patients in Harare, Zimbabwe were genotyped at the superoxide dismutase locus. High genotypic similarity to isolates of P. jirovecii obtained from patients in London, UK was observed. These data provide additional support for the hypothesis that P. jirovecii is genetically indistinguishable in isolates from geographically diverse locations.

Adult↗
PubMed2006

Isolation and phylogenetic analysis of H1N1 swine influenza virus isolated in Korea.

A swine influenza H1N1 virus was isolated from a pig during a severe outbreak of respiratory disease in Korea. All genes of the H1N1 isolate, including hemagglutinin (HA), neuraminidase (NA), matrix (M), nucleoprotein (NP), non-structural (NS), PA, PB1 and PB2, were of swine origin. Also, all these genes showed a close phylogenic relationship with those of H1N1 viruses previously isolated from pigs in the United States. These results suggest that North American swine influenza virus has actually been transmitted to pigs in Korea.

Animals↗
PubMed2002

Antigenic heterogeneity amongst the field isolates of Newcastle Disease Virus (NDV) in relation to the vaccine strain. Part II: studies on viruses isolated from domestic birds in Israel.

Forty three Newcastle disease virus (NDV) strains isolated before and during 1997 in Israel from domestic birds were studied by means of the three panels of monoclonal antibodies prepared against all the viral envelope proteins in order to reveal the possible antigenic differences between them and the VH strain used in Israel for poultry vaccination. Three isolates were found to have significant antigenic differences in the hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins as compared to the vaccine strain. As to the matrix protein, almost all the viruses isolated during the year 1997 were found to have considerable differences from the vaccine strain in two of four antigenic sites.

Animals↗
PubMed2002

Isolation of avian pneumovirus from mallard ducks that is genetically similar to viruses isolated from neighboring commercial turkeys.

Our earlier studies demonstrating avian pneumovirus (APV) RNA in wild geese, sparrows, swallows, starlings and mallard ducks suggested that wild birds might be involved in the circulation of APV in the United States. To determine whether turkey virus can be transmitted to the free flying birds, we placed APV-negative mallard ducks next to a turkey farm experiencing a severe APV outbreak and in an area with a large population of waterfowls. The sentinel ducks did not develop clinical APV disease but infectious APV (APV/MN-12) was recovered from choanal swabs after 2 weeks, and anti-APV antibodies detected after 4 weeks. Four APV isolates recovered from the neighboring turkeys that were experiencing an APV outbreak at the same time shared 95-99% nucleotide identity and 97-99% predicted amino acid identity with the duck isolate. In addition experimental infection of turkey poults with APV/MN-12 resulted in detection of viral RNA in nasal turbinates and APV-specific IgG in serum. These results indicate that the APV isolates from turkeys and ducks shared a common source, and the viruses from different avian species can cross-infect.

Amino Acid Sequence↗