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E Ward

Publications and source records attributed to E Ward.

At least 73 records · Page 4Linked to original sources
PubMed1994

Isolation and characterization of cDNAs encoding imidazoleglycerolphosphate dehydratase from Arabidopsis thaliana.

cDNA clones encoding imidazoleglycerolphosphate dehydratase (IGPD; EC 4.2.1.19) from Arabidopsis thaliana were isolated by complementation of a bacterial auxotroph. The predicted primary translation product shared significant identity with the corresponding sequences from bacteria and fungi. As in yeast, the plant enzyme is monofunctional, lacking the histidinol phosphatase activity present in the Escherichia coli protein. IGPD mRNA was present in major organs at all developmental stages assayed. The Arabidopsis genome appears to contain two genes encoding this enzyme, based on DNA gel blot and polymerase chain reaction analysis.

Amino Acid Sequence↗
PubMed1994

Rising HIV-1 prevalence among sexually transmitted disease clinic attenders in Jamaica: traumatic sex and genital ulcers as risk factors.

Between November 1990 and January 1991, status of human immunodeficiency virus (HIV) infection was assessed for 522 men and 484 women attending the Comprehensive Health Centre in Kingston, Jamaica, for a new sexually transmitted disease (STD) complaint. Prevalence of HIV type 1 (HIV-1) infection was 3.1% (31 of 1,006), a tenfold rise in seroprevalence in 4.5 years. Nineteen of 517 (3.7%) heterosexual men, 3 of 5 (60%) homosexual/bisexual men, and 9 of 484 (1.9%) women were infected with HIV. In heterosexual men, factors associated with HIV infection after age adjustment included present complaint of genital ulcer [odds ratio (OR) 7.3; 95% confidence interval (CI) 1.4-72], past history of genital ulcer (OR, 4.3; CI, 1.4-12), positive MHATP syphilis serology (OR, 3.4; CI, 1.1-10), sex with a prostitute in the past month (OR, 3.8; CI, 1.1-11). Three or more sex partners in the month prior to complaint (OR, 3.6; CI, 1.0-12), and bruising during sex (OR, 4.0; CI, 1.4-13). On multiple logistic regression analysis, independent associations with HIV infection were shown for bruising during sex (OR, 3.0; CI, 1.1-8.3), positive MHATP syphilis serology (OR, 3.2; CI, 1.1-9.5), and history of genital ulcer (OR, 2.9; CI, 1.0-8.0).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Increased tolerance to two oomycete pathogens in transgenic tobacco expressing pathogenesis-related protein 1a.

Expression of pathogenesis-related protein 1a (PR-1a), a protein of unknown biochemical function, is induced to high levels in tobacco in response to pathogen infection. The induction of PR-1a expression is tightly correlated with the onset of systemic acquired resistance (SAR), a defense response effective against a variety of fungal, viral, and bacterial pathogens. While PR-1a has been postulated to be involved in SAR, and is the most highly expressed of the PR proteins, evidence for its role is lacking. In this report, we demonstrate that constitutive high-level expression of PR-1a in transgenic tobacco results in tolerance to infection by two oomycete pathogens, Peronospora tabacina and Phytophthora parasitica var. nicotianae.

Oomycetes↗
PubMed1993

Molecular cloning and sequencing of a cDNA encoding mung bean cytochrome P450 (P450C4H) possessing cinnamate 4-hydroxylase activity.

With the aid of partial amino acid sequences determined for cinnamate 4-hydroxylase (P450C4H) purified from mung bean seedlings, two cDNA clones were isolated and their inserts were completely sequenced. The nucleotide sequences of the two clones were nearly identical and contained an open reading frame predicted to encode a polypeptide consisting of 505 amino acid residues. The partial sequences determined from the purified P450C4H closely corresponded to the primary structures deduced from the cDNA sequences. This is the first isolation of cDNA clones encoding a higher plant P450 possessing clear physiological activity. Comparison to known cytochromes P450 indicated that P450C4H belongs to a novel P450 gene family.

Amino Acid Sequence↗
PubMed1993

Biological monitoring for occupational exposures to o-toluidine and aniline.

Epidemiological evidence that occupational exposure to o-toluidine and aniline is associated with an increased risk of bladder cancer led to efforts to identify biomarkers of workplace exposures to these aromatic amines. For the determination of o-toluidine and aniline in worker urine specimens, a method using high performance liquid chromatography (HPLC) followed by electrochemical detection was developed. The limits of detection were 0.6 microgram/l and 1.4 micrograms/l for o-toluidine and aniline, respectively. Recovery of o-toluidine and aniline from spiked urine averaged 86% and 93%, respectively, over a range of 4-100 micrograms/l. Reproducibility in the range 2-100 micrograms/l for analyses of split field samples was 13% (average RSD) for o-toluidine and 16% (average RSD) for aniline. Application of this method to pre- and post-shift samples collected from potentially exposed and unexposed workers indicated elevated concentrations of o-toluidine and aniline in urine from exposed workers. To develop methods for biomarkers of internal dose, o-toluidine binding to the blood proteins hemoglobin and albumin was investigated utilizing in-vivo (rodent) and in-vitro (hemoglobin and albumin) studies. Base-hydrolyzable protein adducts were analyzed by HPLC (fluorescence) and/or GC/electron capture (EC). The methods were compared for sample preparation requirements, selectivity and sensitivity. While the GC/EC method was more sensitive than HPLC, the presence of interfering peaks limited the utility of this approach. Results from these studies suggested that the HPLC method could be useful for determination of o-toluidine exposures in individuals acutely or chronically exposed to high levels.

Aniline Compounds↗
PubMed1993

Regulation of pathogenesis-related protein-1a gene expression in tobacco.

Pathogenesis-related protein-1a (PR-1a) is a protein of unknown function that is strongly induced during the onset of systemic acquired resistance (SAR) in tobacco. The expression of PR-1a is under complex regulation that is controlled at least partially by the rate of transcription. In this study, we demonstrated that 661 bp of 5' flanking DNA was sufficient to impart tobacco mosaic virus and salicylic acid inducibility to a reporter gene. The PR-1a promoter did not respond significantly to treatments with either auxin or cytokinin. Experiments with the protein synthesis inhibitor cycloheximide indicated that protein synthesis is required for salicylate-dependent mRNA accumulation. At flowering, the PR-1a gene was expressed primarily in the mesophyll and epidermal tissues of the leaf blade and the sepals of the flower. Several artifacts, most importantly ectopic expression in pollen, were associated with the use of the beta-glucuronidase reporter gene.

Adenine↗
PubMed1992

Uses and technique of pediatric lumbar puncture.

OBJECTIVES: To review diagnostic and therapeutic indications, contraindications, complications, and technique of pediatric lumbar puncture with emphasis on diagnosis of bacterial meningitis in bacteremia, cellulitis, and fever with seizures and to discuss cerebrospinal fluid findings in partially treated infection and traumatic blood-contaminated spinal tap. RESEARCH DESIGN: Literature review. CONCLUSIONS: We recommend lumbar puncture for children younger than 1 year with bacteremia, children with Haemophilus influenzae type B cellulitis, and children with fever and seizures not classified as simple. Pretreatment with antibiotics rarely changes cerebrospinal fluid characteristics such that a diagnosis of bacterial meningitis would be obscured. In a traumatic spinal tap, the equation to predict cerebrospinal fluid pleocytosis based on the peripheral blood cell count is invalid. When used together, cerebrospinal fluid glucose level, Gram's staining, and observed-to-expected ratio of white blood cells are highly reliable in diagnosing bacterial meningitis.

Bacteremia↗
PubMed1992

A mortality study of workers at seven beryllium processing plants.

The International Agency for Research on Cancer (IARC) has found that the evidence for the carcinogenicity of beryllium is sufficient based on animal data but "limited" based on human data. This analysis reports on a retrospective cohort mortality study among 9,225 male workers employed at seven beryllium processing facilities for at least 2 days between January 1, 1940, and December 31, 1969. Vital status was ascertained through December 31, 1988. The standardized mortality ratio (SMR) for lung cancer in the total cohort was 1.26 (95% confidence interval [CI] = 1.12-1.42); significant SMRs for lung cancer were observed for two of the oldest plants located in Lorain, Ohio (SMR = 1.69; 95% CI = 1.28-2.19) and Reading, Pennsylvania (SMR = 1.24; 95% CI = 1.03-1.48). For the overall cohort, significantly elevated SMRs were found for "all deaths" (SMR = 1.05; 95% CI = 1.01-1.08), "ischemic heart disease" (SMR = 1.08; 95% CI = 1.01-1.14), "pneumoconiosis and other respiratory diseases" (SMR = 1.48; 95% CI = 1.21-1.80), and "chronic and unspecified nephritis, renal failure, and other renal sclerosis" (SMR = 1.49; 95% CI = 1.00-2.12). Lung cancer SMRs did not increase with longer duration of employment, but did increase with longer latency (time since first exposure). Lung cancer was particularly elevated (SMR = 3.33; 95% CI = 1.66-5.95) among workers at the Lorain plant with a history of (primarily) acute beryllium disease, which is associated with very high beryllium exposure. The lung cancer excess was not restricted to plants operating in the 1940s, when beryllium exposures were known to be extraordinarily high. Elevated lung cancer SMRs were also observed for four of the five plants operating in the 1950s for workers hired during that decade. Neither smoking nor geographic location fully explains the increased lung cancer risk. Occupational exposure to beryllium compounds is the most plausible explanation for the increased risk of lung cancer observed in this study. Continued mortality follow-up of this cohort will provide a more definitive assessment of lung cancer risk at the newer plants and among cohort members hired in the 1950s or later at the older plants. Further clarification of the potential for specific beryllium compounds to induce lung cancer in humans, and the possible contribution of other exposures in specific processes at these plants, would require a nested case-control study. We are currently assessing whether available industrial hygiene data would support such an analysis.

Berylliosis↗
PubMed1992

Acidic and basic class III chitinase mRNA accumulation in response to TMV infection of tobacco.

Complementary DNA clones encoding acidic and basic isoforms of the class III chitinase were isolated from Nicotiana tabacum. The clones share ca. 65% identity, are equally homologous to the class III chitinases from cucumber and Arabidopsis, and are members of small gene families in tobacco. An acidic class III chitinase was purified from the intercellular fluid of tobacco leaves infected with tobacco mosaic virus (TMV). Partial amino acid sequencing of the protein confirmed that it was encoded by one of the cDNA clones. The mRNAs of the class III chitinases are coordinately expressed in response to TMV infection, both in infected and uninfected tissue. The acidic and basic class III chitinases constitute previously undescribed pathogenesis-related proteins in tobacco.

Amino Acid Sequence↗
PubMed1992

Overexpression of plant histidinol dehydrogenase using a baculovirus expression vector system.

A cDNA encoding cabbage histidinol dehydrogenase, including the chloroplast transit peptide sequence, was overexpressed using a baculovirus expression vector system. The maximum level of the expression of histidinol dehydrogenase was reached 5 days after infection of the insect cells. Two forms of recombinant histidinol dehydrogenase with molecular masses of 53 and 52 kDa, respectively, were obtained by a one-step purification from the cell homogenate. Compared with the 52-kDa form, the 53-kDa form contained 10 additional amino acids at the N-terminus derived from the transit peptide. By incubating the cell homogenate for 2 h at 30 degrees C, the 53-kDa form could be completely converted to the 52-kDa form. This conversion was blocked by leupeptin. Eighty percent of the converted 52-kDa form had Cys at position 31 at the N-terminal amino acid and the rest had Met 33. Kinetic properties of the recombinant enzyme were virtually identical to those of histidinol dehydrogenase isolated from cabbage plants. The overexpression of recombinant cabbage histidinol dehydrogenase in insect cells, the proteolytic processing of the preprotein next to the N-terminus (compared to the mature cabbage enzyme), and its easy purification allow the preparation of large amounts of the active enzyme for structural and functional studies.

Alcohol Oxidoreductases↗
PubMed1992

Acquired resistance in Arabidopsis.

Acquired resistance is an important component of the complex disease resistance mechanism in plants, which can result from either pathogen infection or treatment with synthetic, resistance-inducing compounds. In this study, Arabidopsis, a tractable genetic system, is shown to develop resistance to a bacterial and a fungal pathogen following 2,6-dichloroisonicotinic acid (INA) treatment. Three proteins that accumulated to high levels in the apoplast in response to INA treatment were purified and characterized. Expression of the genes corresponding to these proteins was induced by INA, pathogen infection, and salicylic acid, the latter being a putative endogenous signal for acquired resistance. Arabidopsis should serve as a genetic model for studies of this type of immune response in plants.

Amino Acid Sequence↗
PubMed1991

Lung cancer incidence among patients with beryllium disease: a cohort mortality study.

We have conducted a cohort mortality study on 689 patients with beryllium disease who were included in a case registry. An earlier mortality study on 421 of these patients was limited to males and resulted in a determination of a nonsignificant twofold lung cancer excess based on only seven lung cancer deaths. We have extended this earlier study by including females and by adding 13 years of follow-up. Comparison of the 689 beryllium disease patients with the U.S. population resulted in a lung cancer standardized mortality ratio (SMR) of 2.00 (95% confidence interval = 1.33-2.89) based on 28 observed lung cancer deaths. Adjustment for smoking did not change these results. All causes of mortality were also significantly elevated (SMR = 2.19), largely because of the very high rate of deaths due to pneumoconioses (primarily beryllium disease) (SMR = 34.23; 158 deaths). No other causes of death were significantly elevated. The excess of lung cancer was consistent for both sexes and did not appear to increase with duration of exposure to beryllium or with time elapsed since first exposure to this element. The case registry included those with acute beryllium disease, which resembles a chemical pneumonitis, and those with chronic beryllium disease, which resembles other pneumoconioses. The lung cancer excess was more pronounced among those with acute disease (SMR = 2.32) than among those with chronic disease (SMR = 1.57).

Adult↗
PubMed1991

Structural and functional conservation of histidinol dehydrogenase between plants and microbes.

The partial amino acid sequence of histidinol dehydrogenase (L-histidinol:NAD+ oxidoreductase, EC 1.1.1.23) from cabbage was determined from peptide fragments of the purified protein. The relative positions of these peptides were deduced by aligning their sequences with the sequence of the HIS4C gene product of Saccharomyces cerevisiae. cDNA encoding histidinol dehydrogenase was then amplified from a library using a polymerase chain reaction primed with degenerate oligonucleotide pools of known position and orientation. By using this amplified fragment as a probe, an apparently full-length cDNA clone was isolated that is predicted to encode a proenzyme having a putative 31-amino acid chloroplast transit peptide and a mature molecular mass of 47.5 kDa. The predicted protein sequence was 51% identical to the yeast enzyme and 49% identical to the Escherichia coli enzyme. Expression of the cDNA clone in an E. coli his operon deletion strain rendered the mutant able to grow in the presence of histidinol.

Alcohol Oxidoreductases↗
PubMed1991

Excess number of bladder cancers in workers exposed to ortho-toluidine and aniline.

A retrospective cohort study of the incidence of bladder cancer was conducted in response to a union request for an evaluation of a possible excess number of cases of bladder cancer at a chemical plant in western New York State. Workers at the plant were exposed to two potential bladder carcinogens--ortho-toluidine (o-toluidine) and aniline. Incidence rates of bladder cancer among workers at the plant were compared with those of the population of New York State (excluding New York City). Among all 1749 workers at the plant, 13 cases of bladder cancer were observed versus 3.61 expected [standardized incidence ratio (SIR) = 3.60; 90% confidence interval (CI) = 2.13-5.73]. Among the 708 workers who worked in areas in which o-toluidine and aniline were used, 7 cases were observed versus 1.08 expected (SIR = 6.48; 90% CI = 3.04-12.2). Among the 288 maintenance, shipping, and janitorial workers thought to have been possibly exposed, 4 cases were observed versus 1.09 expected (SIR = 3.66; 90% CI = 1.25-8.37). Among the remaining 753 workers who were probably not exposed, 2 bladder cancers were observed versus 1.43 expected (SIR = 1.39; 90% CI = 0.25-4.39). Increased risk of bladder cancer was strongly associated with increased duration of employment in the department where o-toluidine and aniline were used (P less than .001). Among workers with 10 or more years of employment in the department, the SIR was 27.2 (90% CI = 11.8-53.7). o-Toluidine is an animal carcinogen more potent than aniline and is known to produce bladder tumors in rats; hence, it is more likely that o-toluidine is responsible for the observed excess number of cases of bladder cancer, although aniline may have played a role.

Adult↗
PubMed1991

Pathogenesis-related protein 4 is structurally homologous to the carboxy-terminal domains of hevein, Win-1 and Win-2.

The extracellular, acidic pathogenesis-related protein, PR-4, was purified to homogeneity from leaves of Nicotiana tabacum infected with tobacco mosaic virus (TMV) and characterized by partial amino acid sequencing. Complementary DNA clones encoding PR-4 were isolated using an oligonucleotide probe based on the sequence of one of the peptides. The deduced PR-4 protein sequence was found to be related to a family of proteins including hevein and Win-1, which have an amino-terminal lectin domain and a carboxy-terminal domain of unknown function. PR-4 is homologous to the carboxy-terminus of these proteins but does not contain the lectin domain. Thus, the organization of the PR-4 family of proteins is similar to that of the plant chitinase family, in that both contain structural subclasses characterized by the presence or absence of an amino-terminal lectin domain. This observation is consistent with the proposal that the DNA encoding the lectin domain may be capable of transposing to form new genes encoding proteins of more complex, multi-domain structure. The expression of PR-4 mRNA was found to increase dramatically in response to TMV infection and the time course of RNA accumulation was similar to that of other PR proteins.

Amino Acid Sequence↗
PubMed1990

Biological monitoring of a worker acutely exposed to MBOCA.

A 30 year-old male polyurethane worker was exposed to an accidental spill of 4,4'-methylene-bis-2-chloroaniline (MBOCA) at a plant producing MBOCA-cured plastic products. Exposure to MBOCA is significant in that this compound is a known animal carcinogen and a suspected human carcinogen. The employee was sprayed over his upper body and extremities with molten MBOCA while cleaning out a clogged hose from a MBOCA and polymer mixing machine. The subsequent environmental and medical evaluation of this episode included serial urinary MBOCA samples from the worker over a 2 week period to allow the calculation of a biological half-life for this compound. This worker experienced a very high dose of MBOCA as judged by his urinary MBOCA levels (peak value of 1,700 ppb 4 hours after exposure). There were no acute symptoms or other laboratory abnormalities noted. The kinetic evaluation resulted in a biological half-life for MBOCA in urine of approximately 23 hours. Assuming a one-compartment model, approximately 94% of an initial MBOCA dose will be eliminated within four days. This is the first report of kinetic analysis on urinary MBOCA excretion in humans. This information suggests that biological monitoring of the urine MBOCA concentrations in exposed workers may miss peak levels following an acute exposure unless the analyses of the urinary MBOCA are performed in a timely fashion. Recommendations to the company included: 1) installation of a warning system or lock-out device on the mixing machine to prevent the opening of the MBOCA hose prior to the release of pressure; and 2) annual medical surveillance of this individual for bladder cancer with urinalysis and urine cytology.

Accidents, Occupational↗
PubMed1990

Evidence for a third structural class of beta-1,3-glucanase in tobacco.

Glucan endo-1,3-beta-glucosidases (beta-1,3-glucanases) have been implicated in several developmental processes and they may also play a direct role in the plant's defense against fungal pathogens. In an effort to characterize the glucanase gene family, complementary DNA clones encoding an acidic form of beta-1,3-glucanase have been isolated from tobacco. The cDNA was expressed in E. coli and shown to encode a beta-1,3-glucanase activity. The protein sequence encoded by the cDNA was found to match the partial protein sequence of PR-35, a previously characterized beta-1,3-glucanase. The protein encoded by the cDNA was purified from the extracellular fluid of TMV-infected tobacco leaves and found by immunological methods to correspond to glucanase PR-Q'. From a detailed analysis of the cDNA it is clear that this glucanase represents a third structural class of enzyme which differs substantially from both the basic, vacuolar glucanase and the acidic, extracellular forms (PR-2, PR-N and PR-O). It has previously been demonstrated that the basic form of beta-1,3-glucanase is synthesized as a pre-pro-enzyme and upon maturation the 21 amino acid signal peptide and a 22 amino acid carboxy-terminal peptide are removed. This processing event has been proposed to be involved with the vacuolar localization of the enzyme. By comparing the deduced protein structure of PR-Q' to that of the basic form it is evident that this extracellular enzyme is missing the carboxy-terminal 22 amino acids. The role of a conserved phenylalanine-glycine dipeptide in the processing of glucanases and other pathogenesis-related proteins from tobacco is discussed.

Amino Acid Sequence↗