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At least 307 records · Page 17Linked to original sources
PubMed1997

Transgenically Expressed Betaine Aldehyde Dehydrogenase Efficiently Catalyzes Oxidation of Dimethylsulfoniopropionaldehyde and [omega]-Aminoaldehydes.

Tobacco (Nicotianum tabacum L.) plants engineered to express a sugar beet (Beta vulgaris L.) betaine aldehyde dehydrogenase (BADH) cDNA acquired not only BADH activity, but also three other aldehyde dehydrogenase activities (those measured with 3-dimethylsulfoniopropionaldehyde, 3-aminopropionaldehyde, and 4-aminobutyraldehyde, all of which are natural products). This shows that BADH is not, as believed up to now, a substrate-specific enzyme and that its role may not be limited to glycine betaine synthesis.

Journal Article↗
PubMed1988

Stable Transformation of Soybean Callus by DNA-Coated Gold Particles.

Immature soybean (Glycine max L.) embryos from commercially important cultivars were the targets of rapidly accelerated, DNA-coated, gold particles. Protoplasts were prepared from these tissues and propagated in culture under selection conditions for the introduced neomycin phosphotransferase II gene. Kanamycin-resistant calli were obtained at a rate of approximately 10(-5). Enzyme assays and Southern blot hybridization confirmed the expression of the foreign gene and its stable integration into the soybean genome. Our results show that particle acceleration can be used for the introduction of foreign DNA into the soybean genome and indicate the technique may be useful in the recovery of engineered plants by transformation of regenerable tissues.

Journal Article↗
PubMed2003

Cloning, expression, and purification of choline dehydrogenase from the moderate halophile Halomonas elongata.

Choline dehydrogenase (EC 1.1.99.1) catalyzes the four-electron oxidation of choline to glycine-betaine via a betaine-aldehyde intermediate. Such a reaction is of considerable interest for biotechnological applications in that transgenic plants engineered with bacterial glycine-betaine-synthesizing enzymes have been shown to have enhanced tolerance towards various environmental stresses, such as hypersalinity, freezing, and high temperatures. To date, choline dehydrogenase has been poorly characterized in its biochemical and kinetic properties, mainly because its purification has been hampered by instability of the enzyme in vitro. In the present report, we cloned and expressed in Escherichia coli the betA gene from the moderate halophile Halomonas elongata which codes for a hypothetical choline dehydrogenase. The recombinant enzyme was purified to more than 70% homogeneity as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by treatment with 30 to 50% saturation of ammonium sulfate followed by column chromatography using DEAE-Sepharose. The purified enzyme showed similar substrate specificities with either choline or betaine-aldehyde as the substrate, as indicated by the apparent V/K values (where V is the maximal velocity and K is the Michaelis constant) of 0.9 and 0.6 micro mol of O(2) min(-1) mg(-1) mM(-1) at pH 7 and 25 degrees C, respectively. With 1 mM phenazine methosulfate as the primary electron acceptor, the apparent V(max) values for choline and betaine-aldehyde were 10.9 and 5.7 micro mol of O(2) min(-1) mg(-1), respectively. These V(max) values decreased four- to sevenfold when molecular oxygen was used as the electron acceptor. Altogether, the kinetic data are consistent with the conclusion that H. elongata betA codes for a choline dehydrogenase that can also act as an oxidase when electron acceptors other than molecular oxygen are not available.

Alcohol Oxidoreductases↗
PubMed1995

Efficient system of homologous RNA recombination in brome mosaic virus: sequence and structure requirements and accuracy of crossovers.

Brome mosaic virus (BMV), a tripartite positive-stranded RNA virus of plants engineered to support intersegment RNA recombination, was used for the determination of sequence and structural requirements of homologous crossovers. A 60-nucleotide (nt) sequence, common between wild-type RNA2 and mutant RNA3, supported efficient repair (90%) of a modified 3' noncoding region in the RNA3 segment by homologous recombination with wild-type RNA2 3' noncoding sequences. Deletions within this sequence in RNA3 demonstrated that a nucleotide identity as short as 15 nt can support efficient homologous recombination events, while shorter (5-nt) sequence identity resulted in reduced recombination frequency (5%) within this region. Three or more mismatches within a downstream portion of the common 60-nt RNA3 sequence affected both the incidence of recombination and the distribution of crossover sites, suggesting that besides the length, the extent of sequence identity between two recombining BMV RNAs is an important factor in homologous recombination. Site-directed mutagenesis of the common sequence in RNA3 did not reveal a clear correlation between the stability of predicted secondary structures and recombination activity. This indicates that homologous recombination does not require similar secondary structures between two recombining RNAs at the sites of crossovers. Nearly 20% of homologous recombinants were imprecise (aberrant), containing either nucleotide mismatches, small deletions, or small insertions within the region of crossovers. This implies that homologous RNA recombination is not as accurate as proposed previously. Our results provide experimental evidence that the requirements and thus the mechanism of homologous recombination in BMV differ from those of previously described heteroduplex-mediated nonhomologous recombination (P. D. Nagy and J. J. Bujarski, Proc. Natl. Acad. Sci. USA 90:6390-6394, 1993).

Base Sequence↗
PubMed1998

Lung cancer mortality in nickel/chromium platers, 1946-95.

OBJECTIVES: To investigate mortality from lung cancer in nickel/chromium platers. METHODS: The mortality experience of a cohort of 1762 chrome workers (812 men, 950 women) from a large electroplating and light engineering plant in the Midlands, United Kingdom, was investigated for the period 1946-95. All subjects were first employed in chrome work at the plant during the period 1946-75, and had at least six months employment in jobs associated with exposure to chromic acid mist (hexavalent chromium). Detailed job histories were abstracted from original company personnel records and individual cumulative durations of employment in three types of chrome work were derived as time dependent variables (chrome bath work, other chrome work, any chrome work). Two analytical approaches were used--indirect standardisation and Poisson regression. RESULTS: Based on mortalities for the general population of England and Wales, male workers with some period of chrome bath work had higher lung cancer mortalities (observed deaths 40, expected deaths 25.41, standardised mortality ratio (SMR) 157, 95% confidence interval (95% CI) 113 to 214, p < 0.01) than did other male chrome workers (observed 9, expected 13.70, SMR 66, 95% CI 30 to 125). Similar findings were shown for female workers (chrome bath workers: observed 15, expected 8.57, SMR 175, 95% CI 98 to 289, p = 0.06; other chrome workers: observed 1, expected 4.37, SMR 23, 95% CI 1 to 127). Poisson regression was used to investigate risks of lung cancer relative to four categories of cumulative duration of chrome bath work and four categories of cumulative duration of other chrome work (none, < 1 y, 1-4 y, > or = 5 y). After adjusting for sex, age, calendar period, year of starting chrome work, period from first chrome work, and employment status (still employed v left employment), there was a significant positive trend (p < 0.05) between duration of chrome bath work and risks of mortality for lung cancer. Relative to a risk of unity for those chrome workers without any period of chrome bath work, risks were 2.83 (95% CI 1.47 to 5.45), 1.61 (95% CI 0.75 to 3.44), and 4.25 (95% CI 1.83 to 9.87) for the second, third, and fourth exposure categories, respectively. Duration of other chrome work was not a useful predictor of risks of lung cancer. Similar findings for both variables were obtained when adjustment was made for sex and age only. Similar findings for both variables were obtained relative to risk of chrome nasal ulceration. CONCLUSIONS: The findings are consistent with the hypothesis that soluble hexavalent chromium compounds are potent human lung carcinogens.

Adult↗
PubMed1997

Simulated airborne spread of Aujeszky's disease and foot-and-mouth disease.

The atmospheric dispersion of virus was simulated using a computer model which had been developed for predicting the dispersion of toxic gases from chemical engineering plants. The results were compared with data from four outbreaks in which virus was believed to have been transported by air: two outbreaks of foot-and-mouth disease in the United Kingdom in 1967 and outbreaks of Aujeszky's disease in Yorkshire in 1981 to 1982 and Indiana in 1988. There was relatively good agreement with most of these data. The paper shows that the model could be useful in an emergency because the risk of virus spread could be predicted in real time.

Air Microbiology↗
PubMed2006

High magnetic field induced changes of gene expression in arabidopsis.

BACKGROUND: High magnetic fields are becoming increasingly prevalent components of non-invasive, biomedical imaging tools (such as MRI), thus, an understanding of the molecular impacts associated with these field strengths in biological systems is of central importance. The biological impact of magnetic field strengths up to 30 Tesla were investigated in this study through the use of transgenic Arabidopsis plants engineered with a stress response gene consisting of the alcohol dehydrogenase (Adh) gene promoter driving the beta-glucuronidase (GUS) gene reporter. METHODS: Magnetic field induced Adh/GUS activity was evaluated with histochemical staining to assess tissue specific expression and distribution, and with quantitative, spectrofluometric assays to measure degree of activation. The evaluation of global changes in the Arabidopsis genome in response to exposure to high magnetic fields was facilitated with Affymetrix Gene Chip microarrays. Quantitative analyses of gene expression were performed with quantitative real-time polymerase-chain-reaction (qRT-PCR). RESULTS: Field strengths in excess of about 15 Tesla induce expression of the Adh/GUS transgene in the roots and leaves. From the microarray analyses that surveyed 8000 genes, 114 genes were differentially expressed to a degree greater than 2.5 fold over the control. These results were quantitatively corroborated by qRT-PCR examination of 4 of the 114 genes. CONCLUSION: The data suggest that magnetic fields in excess of 15 Tesla have far-reaching effect on the genome. The wide-spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism, are prominent examples. The roles of magnetic field orientation of macromolecules and magnetophoretic effects are discussed as possible factors that contribute to the mounting of this response.

Journal Article↗
PubMed2002

Genetic-biochemical criteria for individual sensitivity in development of occupational bronchopulmonary diseases.

Human individual sensitivity to health-hazardous occupational factors and probability of developing chronic lung diseases depend on genetic variation of serum and erythrocytic proteins. The present work was aimed at studying the phenotypes of serum and erythrocytic proteins in patients with occupational respiratory diseases. We studied 7 highly polymorphic genetic systems the varieties of which may be connected with development of bronchopulmonary pathology (BPP) and the immune status of the body: proteinase inhibitor (Pi), third component of the complement (C3), transferrin (Tf), group-specific component of blood serum (Gc), haptoglobin (Hp), erythrocytic glyoxalase (Glo) and phosphoglucomutase (PGM) in patients with chronic bronchitis, silicosis, occupational bronchial asthma and in the control group consisting of Moscow population not exposed to occupational hazards and apparently healthy workers of an engineering plant. Considerable differences were revealed in genetic structure of the patients with bronchopulmonary pathology as compared with the apparently healthy people along a series of Integrated system: proteinase inhibitor (Pi), C3, Tf, Gc, PGM. Comparison of the study groups by significant differences in the aggregate of the genetic information obtained suggests that 5 (HP, C3, Tf, Pl, PGM1) of the 7 studied systems showed the hereditary features of silicosis. The gene carriers Hp*2, C3*F, PGM1*2-, TF*D, GC*R due to peculiar biochemical processes appear to have less adaptive potentialities and a greater likelihood of the disease on exposure to industrial factors. The examined patients with chronic bronchitis showed an increase in the variant of GC*2 and of a rare variants of proteins GC*R and Pi*S, the patients with occupational bronchial asthma showed an increase in the variant of Hp*2 and of a rare variant Pi*S. Such studies could be useful for assessment and forecast of individual risk of occupational diseases.

Alleles↗
PubMed2004

[Review on plant gene promoters].

Promoters are the important regulation factors/elements in gene expression. In this paper, the structure and function of promoters are analyzed and reviewed. Plant gene promoters are classified into constitutive promoters, inducible promoters, tissue (spatial) and developmental (temporary) specific promoters. The bi-directional promoters existed in nature and reconstructed artificially by some strategies are introduced and their applications in plant genetic engineering are prospected.

Genetic Engineering↗
PubMed1991

Heat stress disorders. Old problems, new implications.

Occupational health nurses must always be aware of changing job tasks that create new classes of employees at risk for developing heat stress disorders. Examples include chemical handlers or asbestos containment specialists who must wear non-permeable protective clothing. Heat induced occupational illnesses and injuries, and reduced productivity occur in situations in which the total heat load (environment plus metabolic heat) exceeds the capacities of the body to maintain normal body functions without strain. Health screening should include evaluation of an employee's age, sex, body size, level of fitness, chronic diseases, use of medications, drugs and alcohol, and ability to acclimate. Prevention of heat stress disorders is a team effort. The occupational health nurse, plant engineer, safety/industrial hygienist, and the employee all impact on the success of any heat stress disorder prevention program. Without cooperation, the possibility for harm exists.

Body Temperature Regulation↗
PubMed1989

[Improving the organization of primary health care for invalids with impaired vision].

The results of the work of 6 health posts at electrical engineering plants of the Ukrainian Society of treh Blind are presented. The number of attendencies for invalids with eyesight disorders constituted 29.5 annually, for those with good eyesight it was 6.7. Time losses for a curative and diagnostic consultation and provision of medical care to invalids of the Ist group with eyesight disorders exceeded the time necessary for rendering care to those who could see by 31-34%. Feldshers spent 43.6% of their working time and medical nurses 65.3% on medical care. Attendencies associated with psychic disorders were listed as one of the biggest health problems in the disease pattern of the blind and those with weak eyesight, 91.1% of psychic cases being attributed to vegeto-vascular dystonia, diseases of the circulatory system, injuries and their aftereffects. A set of proposals was developed, thus it became possible to regulate the work of the health personnel of health posts at the enterprises belonging to the Society of the Blind.

Blindness↗
PubMed1976

[Chronic bronchitis and dust concentration at the place of work (author's transl)].

In connection with the chronic bronchitis key program of the German Research Society 1501 workers in a Munich engineering plant with foundry were examined from 1965 to 1970. With increasing exposure to dust at the work place, bronchitic symptoms such as coughing and sputum become significantly more frequent. Obstructive ventilation disturbances do not increase. Heavy smokers show an overwhelmingly greater frequency of bronchitic symptoms than those exposed to excessive dust. The increase in bronchial obstruction in relation to the consumption of tobacco is remarkable. The effect of age seems to be rather less than that of smoking and greater than that of dust.

Adult↗
PubMed2000

Comparison of genetically engineered microbial and plant phytase for young broilers.

This study was conducted to compare the efficacy of genetically engineered microbial (Natuphos) and plant (Phytaseed) phytase for enhancing the utilization of phytate P in corn-soybean meal-based diets fed to young broilers and to evaluate the safety of Phytaseed phytase. Three levels of each of the two sources of phytase (250, 500, and 2,500 U/kg of diet) were added to a corn-soybean meal basal diet containing 0.46% total P, 0.21% nonphytate P, and 0.92% Ca. There were eight cages per treatment (eight birds per cage for Weeks 2 to 3 and seven birds for Weeks 4 to 5), except for the basal diet without added phytase that had 16 cages. Cage BW and feed consumption were recorded weekly. During Week 5, cage excreta samples were collected for determination of apparent retention coefficients of DM, Ca, and P. At the end of Week 5, all birds were killed, and the left and right toes were removed for determination of toe ash weight and percentage. Forty birds (one per cage from the diet without added phytase and diets with 500 or 2,500 U phytase/kg from both sources) were randomly selected for gross necropsy and histologic evaluation of liver, kidney, and bone tissues. Addition of both sources of phytase resulted in similar increases (P < 0.05) of BW gain; feed intake; gain:feed; apparent retention of DM, P and Ca; and toe measurements. Phosphorus excretion decreased as phytase addition increased. No significant abnormalities were seen in any of the 40 broilers necropsied. Further, the fit of a nonlinear function revealed that most measurements reached a plateau at 2,500 U/kg. Based on performance, bone characteristics, and retention of P, Ca, and DM of young broilers, the efficacy of Phytaseed phytase was similar to that of Natuphos phytase for enhancing the utilization of phytate P in corn-soybean meal-based diets. General necropsy and histologic examination of liver, kidney, and tibial tissues revealed no adverse effects of phytase source or level.

6-Phytase↗
PubMed1995

Modification of the substrate specificity of an acyl-acyl carrier protein thioesterase by protein engineering.

The plant acyl-acyl carrier protein (ACP) thioesterases (TEs) are of biochemical interest because of their roles in fatty acid synthesis and their utilities in the bioengineering of plant seed oils. When the FatB1 cDNA encoding a 12:0-ACP TE (Uc FatB1) from California bay, Umbellularia californica (Uc) was expressed in Escherichia coli and in developing oilseeds of the plants Arabidopsis thaliana and Brassica napus, large amounts of laurate (12:0) and small amounts of myristate (14:0) were accumulated. We have isolated a TE cDNA from camphor (Cinnamomum camphorum) (Cc) seeds that shares 92% amino acid identity with Uc FatB1. This TE, Cc FatB1, mainly hydrolyzes 14:0-ACP as shown by E. coli expression. We have investigated the roles of the N- and C-terminal regions in determining substrate specificity by constructing two chimeric enzymes, in which the N-terminal portion of one protein is fused to the C-terminal portion of the other. Our results show that the C-terminal two-thirds of the protein is critical for the specificity. By site-directed mutagenesis, we have replaced several amino acids in Uc FatB1 by using the Cc FatB1 sequence as a guide. A double mutant, which changes Met-197 to an Arg and Arg-199 to a His (M197R/R199H), turns Uc FatB1 into a 12:0/14:0 TE with equal preference for both substrates. Another mutation, T231K, by itself does not effect the specificity. However, when it is combined with the double mutant to generate a triple mutant (M197R/R199H/T231K), Uc FatB1 is converted to a 14:0-ACP TE. Expression of the double-mutant cDNA in E. coli K27, a strain deficient in fatty acid degradation, results in accumulation of similar amounts of 12:0 and 14:0. Meanwhile the E. coli expressing the triple-mutant cDNA produces predominantly 14:0 with very small amounts of 12:0. Kinetic studies indicate that both wild-type Uc FatB1 and the triple mutant have similar values of Km,app with respect to 14:0-ACP. Inhibitory studies also show that 12:0-ACP is a good competitive inhibitor with respect to 14:0-ACP in both the wild type and the triple mutant. These results imply that both 12:0- and 14:0-ACP can bind to the two proteins equally well, but in the case of the triple mutant, the hydrolysis of 12:0-ACP is severely impaired. The ability to modify TE specificity should allow the production of additional "designer oils" in genetically engineered plants.

Amino Acid Sequence↗
PubMed2003

[Genetic engineering of forest woody plants].

The present state of genetic engineering (GE) of forest woody plants is considered with special reference to the materials of the International Conference "Wood, Breeding, Biotechnology and Industrial Expectations" held in France in June, 2001. Main tree species subjected to GE are listed, aims of constructing transgenic plants discussed, and methods described. Major achievements in the field are considered along with the problems associated with the employment of GE in the breeding of forest woody plants.

Biotechnology↗
PubMed2004

Increased and altered fragrance of tobacco plants after metabolic engineering using three monoterpene synthases from lemon.

Wild-type tobacco (Nicotiana tabacum) plants emit low levels of terpenoids, particularly from the flowers. By genetic modification of tobacco cv Petit Havana SR1 using three different monoterpene synthases from lemon (Citrus limon L. Burm. f.) and the subsequent combination of these three into one plant by crossings, we show that it is possible to increase the amount and alter the composition of the blend of monoterpenoids produced in tobacco plants. The transgenic tobacco plant line with the three introduced monoterpene synthases is emitting beta-pinene, limonene, and gamma-terpinene and a number of side products of the introduced monoterpene synthases, from its leaves and flowers, in addition to the terpenoids emitted by wild-type plants. The results show that there is a sufficiently high level of substrate accessible for the introduced enzymes.

Base Sequence↗
PubMed2002

Surrogate biochemistry: use of Escherichia coli to identify plant cDNAs that impact metabolic engineering of carotenoid accumulation.

Carotenoids synthesized in plants but not animals are essential for human nutrition. Therefore, ongoing efforts to metabolically engineer plants for improved carotenoid content benefit from the identification of genes that affect carotenoid accumulation, possibly highlighting potential challenges when pyramiding traits represented by multiple biosynthetic pathways. We employed a heterologous bacterial system to screen for maize cDNAs encoding products that alter carotenoid accumulation either positively or negatively. Genes encoding carotenoid biosynthetic enzymes from the bacterium Erwinia uredovora were introduced into Escherichia coli cells that were subsequently transfected with a maize endosperm cDNA expression library; and these doubly transformed cells were then screened for altered carotenoid accumulation. DNA sequencing and characterization of one cDNA class conferring increased carotenoid content led to the identification of maize cDNAs encoding isopentenyl diphosphate isomerase. A cDNA that caused a reduced carotenoid content in E. coli was also identified. Based on DNA sequence analysis, DNA hybridization, and further functional testing, this latter cDNA was found to encode the small subunit of ADP-glucose pyrophosphorylase, a rate-controlling enzyme in starch biosynthesis that has been of interest for enhancing plant starch content.

Amino Acid Sequence↗