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PubMed1996

Environmental stress sensitivity of an ascorbic acid-deficient Arabidopsis mutant.

L-ascorbic acid (vitamin C) is a powerful reducing agent found in millimolar concentrations in plants, and is proposed to play an important role in scavenging free radicals in plants and animals. However, surprisingly little is known about the role of this antioxidant in plant environmental stress adaptation or ascorbate biosynthesis. We report the isolation of soz1, a semi-dominant ozone-sensitive mutant that accumulates only 30% of the normal ascorbate concentration. The results of genetic approaches and feeding studies show that the ascorbate concentration affects foliar resistance to the oxidizing gas ozone. Consistent with the proposed role for ascorbate in reactive oxygen species detoxification, lipid peroxides are elevated in soz1, but not in wild type following ozone fumigation. We show that the soz1 mutant is hypersensitive to both sulfur dioxide and ultraviolet B irradiation, thus implicating ascorbate in defense against varied environmental stresses. In addition to defining the first ascorbate deficient mutant in plants, these results indicate that screening for ozone-sensitive mutants is a powerful method for identifying physiologically important antioxidant mechanisms and signal transduction pathways. Analysis of soz1 should lead to more information about the physiological roles and metabolism of ascorbate.

Arabidopsis↗
PubMed2006

ADSA Foundation Scholar Award: Implementing waste solutions for dairy and livestock farms.

Water quality in the United States is threatened by contamination with nutrients, primarily nitrogen (N) and phosphorus (P). Animal manure can be a valuable resource for farmers, providing nutrients, improving soil structure, and increasing vegetative cover to reduce erosion potential. At the same time, application of manure nutrients in excess of crop requirements can result in environmental contamination. Concentrated animal agriculture has been identified as a significant source of nutrient contamination of surface water, nitrogen contamination of groundwater, and ammonia emission. Areas facing the dilemma of an economically important livestock industry concentrated in an environmentally sensitive area have few options. If agricultural practices continue as they have in the past, despite the significant changes in agricultural intensity and changing environmental conditions, continued damage to water resources and a loss of fishing and recreational activity are inevitable. If agricultural productivity is reduced, however, the maintenance of a stable farm economy, a viable rural economy, and a reliable domestic food supply are seriously threatened. The identification and implementation of solutions to the generation of excess manure in confined animal feeding operations are necessary to enable such agricultural operations to thrive in environmentally sensitive areas such as the Chesapeake Bay Watershed. This paper will review an innovative collaborative approach to the development of a manure and litter solutions strategy by a diverse array of potential problem-solvers.

Agriculture↗
PubMed1990

An electromagnetic cervical range-of-motion system and its sensitivity to environmental metal.

A three-dimensional cervical spine range-of-motion system was developed using an electromagnetic tracking system for data collection and a personal computer for analysis and graphic representation of the data. A test was designed to investigate the sensitivity of the electromagnetic device to the proximity of metal. It was found that position errors could be kept below 0.5 cm, and rotation errors could be kept below 1.3 degrees , if all metal was at least 33 cm from the source and sensor. The sensitivity of the system to metal should not cause serious problems in the typical clinical environment if simple precautions are taken.

Cervical Vertebrae↗
PubMed2002

High-performance real-time quantitative RT-PCR using lanthanide probes and a dual-temperature hybridization assay.

We report a time-resolved fluorescence-based, homogeneous approach for multiplex, real-time or end-point detection of PCR products. Signal generation consists of PCR associated digestion of a 5'-labeled oligonucleotide probe, rapid cooling of the reaction mixture, and hybridization of undigested probe oligonucleotides with a complementary, shorter probe that incorporates a quencher at its 3' end. The signal coming from intact fluorescent probe molecules is, thus, quenched. The fluorophores we have used are environmentally sensitive lanthanide chelates. Their signals can be measured in a time-resolved manner that eliminates most of the unspecific fluorescent background. Signal-to-noise ratios are further enhanced by the environmental sensitivity of these chelates; they exhibit a higher fluorescence intensity when free in solution than when coupled to intact probe molecules. Because of the minimal background fluorescence, the signal-to-noise ratios are higher and threshold cycles are lower than those obtained using conventional TaqMan probes. The multiplexing capacity of the assay chemistry is demonstrated through simultaneous amplification and detection of prostate specific antigen (PSA) cDNA and an internal standard mRNA (mmPSA) using probes labeled with terbium and europium. The applicability of the assay chemistry to routine clinical diagnostics is demonstrated through absolute quantification of PSA mRNA in peripheral blood.

Europium↗
PubMed2006

Retinal functional development is sensitive to environmental enrichment: a role for BDNF.

Retina has long been considered less plastic than cortex or hippocampus, the very sites of experience-dependent plasticity. Now, we show that retinal development is responsive to the experience provided by an enriched environment (EE): the maturation of retinal acuity, which is a sensitive index of retinal circuitry development, is strongly accelerated in EE rats. This effect is present also in rats exposed to EE up to P10, that is before eye opening, suggesting that factors sufficient to trigger retinal acuity development are affected by EE during the first days of life. Brain derived neurotrophic factor (BDNF) is precociously expressed in the ganglion cell layer of EE with respect to non-EE rats and reduction of BDNF expression in EE animals counteracts EE effects on retinal acuity. Thus, EE controls the development of retinal circuitry, and this action depends on retinal BDNF expression.

Animals↗
PubMed1982

[A protease of the external membrane of Escherichia coli sensitive to environmental conditions. Its relations with the expression of envZ gene].

A mutant strain (called Cpr), devoid of the outer membrane protease that cleaves colicin A, has been isolated. The location on the genetic map of the cpr locus as well as its pleiotropic effects concerning chiefly: the protein composition of the outer membrane, sensitivity to phages and colicins, alteration in protease activity (cpr), are very similar to the location on the genetic map and to phenotypic properties observed in strains tpo, perA or envZ which are altered in the ompB locus. Conditions resulting in inhibition of the colicin A protease activity also result in transcriptional regulation of OmpF, OmpC and LamB proteins synthesis. The possibility for this protease to be an osmosensor of the cell's external environment is discussed.

Cell Membrane↗
PubMed1982

Temperature and oxygen effects on C-photosynthate unloading and accumulation in developing soybean seeds.

The environmental sensitivity of the processes associated with the import of photosynthate by developing soybean seeds was investigated within intact fruit and with excised, immature embryos. Intact pods of field-grown (Glycine max [L.] Merr.) Amsoy 71 soybeans were subjected to localized regimes of 0, 21, or 100% O(2) and 15, 25, or 35 degrees C during pulsechase translocation experiments and, 2.5 hours later, the uptake and distribution of (14)C-photosynthate among dissected fruit tissues determined. In other experiments, excised embryos were incubated in [(14)C]sucrose solutions under various experimental conditions to separate the effects of these treatments on accumulation by the embryos from those which may operate on phloem unloading in the maternal seedcoat.Import of (14)C-photosynthate by intact soybean fruit was both temperature- and O(2)-dependent. This dependency was shown to occur only within the seeds; import by the pod walls was essentially insensitive to fruit temperature or O(2) treatments. The embryos of anaerobic fruit were completely unlabeled, regardless of fruit temperature. But under anaerobic in vitro incubation conditions, uptake of [(14)C]sucrose in excised embryos was only 30% less than that in aerobic in vitro conditions. The data suggest that, within intact fruit, anoxia prevented sucrose efflux from the seed coat phloem and any subsequent uptake by the embryo. The demonstrated energy dependence of phloem unloading may reflect requirements for membrane integrity or energy metabolism in the companion cell-sieve element complex, consistent with a facilitated unloading process.Collectively, these data characterize the environmental sensitivity of photosynthate import in developing soybean fruit. They imply that environmental regulation of import may occur at both the embryo level and at the phloem terminals within the seed coat.

Journal Article↗
PubMed1982

Biochemical polymorphisms in the South African springbok (Antidorcas marsupialis).

An attempt was made to use polymorphic markers in the genetic taxonomy of springbok populations. Three independent free ranging springbok populations could be identified on the basis of albumin and transferrin gene frequencies. Even if most of the enzyme markers appeared to be monomorphic it can be stated that in any comparative study of this kind, cryptic genetic markers are of greater use than other environmentally sensitive taxonomic criteria. From the given data and others mentioned it can be stated that little support exists for the continued application of the subspecific status in the species Antidorcas marsupialis. It is shown that the use of environmentally sensitive parameters in the springbok are both misleading and highly unsatisfactory. Biochemical polymorphism can be utilized better than other parametres but here also there are several limitations. Basically, only the albumin and transferrin types can be used when blood samples are available and only IDH and 6-PGD polymorphisms are of value when liver samples can be utilized for the genetic differentiation.

Animals↗
PubMed1995

Influence of heredity on human sensitivity to environmental chemicals.

Hereditary peculiarities in individual responses to environmental chemicals are a common occurrence in human populations. Genetic variation in glutathione S-transferase, CYP1A2, N-acetyltransferase, and paraoxonase exemplify the relationship of metabolic variation to individual susceptibility to cancer and other toxicants of environmental origin. Heritable receptor protein variants, a subset of proteins of enormous pharmacogenetic potential that have not thus far been extensively explored from the pharmacogenetic standpoint, are also considered. Examples of interest that are considered include receptor variants associated with retinoic acid resistance in acute promyelocytic leukemia, with paradoxical responses to antiandrogens in prostate cancer, and with retinitis pigmentosa. Additional heritable protein variants of pharmacogenetic interest that result in antibiotic-induced deafness, glucocorticoid-remediable aldosteronism and hypertension, the long-QT syndrome, and beryllium-induced lung disease are also discussed. These traits demonstrate how knowledge of the molecular basis and mechanism of the variant response may contribute to its prevention in sensitive persons as well as to improved therapy for genetically conditioned disorders that arise from environmental chemicals.

Carcinogens, Environmental↗
PubMed2006

Multi-criteria assessment of tensions in resource use at continental scale: a proof of concept with Australian rangelands.

The purpose of this study was to help to inform policy development for the Australian rangelands, and provide a proof of concept for application of a multi-criteria analysis approach to assessment of competing resource use at continental scale. The study aimed to identify and locate key natural resource and agricultural production assets in the rangelands, define a number of measures of potentially threatening processes, and use a multi-criteria approach to identify areas where threatening processes, agricultural production problems, or valuable natural resources coincided. The analysis used 35 readily available, continental spatial data layers at 5-km pixel resolution ranked from 1 (low) to 5 (high) under three themed groupings: natural resource base, production base, and threatening processes. These measures were aggregated into composite indicators to define attributes such as environmental sensitivity and total grazing pressure. The composites were then compared in a two-way analysis to explore particular interactions between threatening processes such as pastoralism and mining, and the condition of production and natural resource assets. These interactions were defined as "tensions" for purposes of this analysis. Example "tensions" included the association of high grazing intensity with areas of high environmental sensitivity, indicating a risk of land degradation under adverse climatic conditions. A summary of patterns of tension was obtained by extracting area proportions of high-tension classes for selected Natural Heritage Trust Regions, which are a basis for Australian Government funding of improved environmental management. The study provides a basis for further examination of trade-offs in the use of natural assets, opportunities for improved productivity and sustainability, and social and economic implications.

Agriculture↗
PubMed1993

Long-term sensitization and environmental conditioning in terrestrial snails.

The hypothesis that a long-term increase of behavioural responses in snails (over a period of days) might be due to environmental conditioning was examined. Training consisted of delivering electric shocks non-contingently with test stimuli twice per day for 5 days to freely moving snails on a ball floating in water. After training, a significant difference in amplitude of a withdrawal reaction to tactile test stimulation appeared between shocked and control snails. Responses were significantly facilitated in shocked animals for up to 12 days after training, but only if the animals were tested in the environment used for training. Testing of the same groups of animals crawling freely on the glass lid of a tank in which they lived between experimental sessions revealed no difference in responses to the same stimuli between shocked and control snails. Injection of the neurotoxin 5,7-dihydroxytryptamine, which selectively impairs serotonergic cells, eliminated the differences between shocked and control animals. Changing the pH of the water in which the ball floated, by addition of citric acid, led to a significant selective increase of responsiveness in snails sensitized in this environment relative to the responsiveness of the same snails with normal water in the tank. The results suggest that the long-term sensitization of withdrawal reactions observed is at least in part a manifestation of an associative process, namely environmental conditioning.

5,7-Dihydroxytryptamine↗
PubMed1993

Neurogenic inflammation and sensitivity to environmental chemicals.

Neurogenic inflammation as a pathway distinct from antigen-driven, immune-mediated inflammation may play a pivotal role in understanding a broad class of environmental health problems resulting from chemical exposures. Recent progress in understanding the mediators, triggers, and regulation of neurogenic inflammation is reviewed. Evidence for and speculations about a role for neurogenic inflammation in established disorders such as asthma, rhinitis, contact dermatitis, migraine headache, and rheumatoid arthritis are presented. The sick building syndrome and multiple chemical sensitivity syndrome have been defined as clinical entities in which exposure to chemical inhalants gives rise to disease. Current data on the existence of chemical irritant receptors in the airway and skin are discussed; neurogenic inflammation arising from stimulation of chemical irritant receptors is a possible model to explain many of the aspects of chemical sensitivities.

Air Pollutants↗
PubMed2004

Epistasis and its relationship to canalization in the RNA virus phi 6.

Although deleterious mutations are believed to play a critical role in evolution, assessing their realized effect has been difficult. A key parameter governing the effect of deleterious mutations is the nature of epistasis, the interaction between the mutations. RNA viruses should provide one of the best systems for investigating the nature of epistasis because the high mutation rate allows a thorough investigation of mutational effects and interactions. Nonetheless, previous investigations of RNA viruses by S. Crotty and co-workers and by S. F. Elena have been unable to detect a significant effect of epistasis. Here we provide evidence that positive epistasis is characteristic of deleterious mutations in the RNA bacteriophage phi 6. We estimated the effects of deleterious mutations by performing mutation-accumulation experiments on five viral genotypes of decreasing fitness. We inferred positive epistasis because viral genotypes with low fitness were found to be less sensitive to deleterious mutations. We further examined environmental sensitivity in these genotypes and found that low-fitness genotypes were also less sensitive to environmental perturbations. Our results suggest that even random mutations impact the degree of canalization, the buffering of a phenotype against genetic and environmental perturbations. In addition, our results suggest that genetic and environmental canalization have the same developmental basis and finally that an understanding of the nature of epistasis may first require an understanding of the nature of canalization.

Bacteriophage phi 6↗
PubMed1999

The relationships among environmental allergen sensitization, allergen exposure, pulmonary function, and bronchial hyperresponsiveness in the Childhood Asthma Management Program.

BACKGROUND: Sensitivity and exposure to indoor allergens constitutes a risk factor for the development and persistence of asthma in children. OBJECTIVE: Our purpose was to evaluate the relationship between sensitivity and exposure to inhalant allergens and lung function and bronchial responsiveness in a group of children (n = 1041) aged 8.9 +/- 2.1 years with mild to moderate asthma enrolled in the Childhood Asthma Management Program (CAMP). METHODS: With use of the extensive CAMP baseline cross-sectional data on spirometry, bronchial responsiveness, allergen sensitivities, and household allergen levels, the relationship of sensitization and exposure to allergens to lung function and methacholine sensitivity was evaluated. Children who enrolled in CAMP stopped all antiasthma medication except rescue use of albuterol and prednisone for exacerbations during the 5- to 16-week screening period. During the last 2 of these weeks they underwent spirometry and methacholine challenge. Indoor allergen exposures were determined from questionnaires completed by the parent. Household levels of indoor allergens (mite, cat, dog, cockroach, mold) were determined on house dust samples. Allergen sensitivity was determined by percutaneous skin testing with a standard battery of allergens plus locally important pollen and fungal spores. Lung function and bronchial hyperresponsiveness were compared for children sensitive and not sensitive to both indoor and outdoor allergens on skin testing and, if sensitive, for exposed and not exposed to the allergens to which they were positive on skin testing. RESULTS: There was a strong direct correlation between increased sensitivity to inhaled methacholine and skin test sensitivity to tree, weed, Alternaria, cat, dog, and indoor molds. When the relationship was examined by stepwise regression, the skin test sensitivities showing the strongest associations with the concentration of methacholine that caused a 20% fall in FEV(1) were dog (P =.003), Alternaria (P =.01), and cat (P =.05). Children sensitive to any one of the aeroallergens tested were compared for the presence or absence of exposure to that allergen at the time that the methacholine challenge was performed. Those who were sensitive and exposed to weed and cat had greater methacholine sensitivity than those similarly sensitive but not exposed (P =.003 and P =.02, respectively). CONCLUSIONS: Sensitivity to dog or cat dander or Alternaria by skin testing was associated with increased bronchial responsiveness but not decreased lung function in children with mild to moderate asthma. These findings support the important role that sensitization to certain allergens plays in modulating bronchial responsiveness.

Adolescent↗
PubMed2002

Construction of a fluorescent biosensor family.

Bacterial periplasmic binding proteins (bPBPs) are specific for a wide variety of small molecule ligands. bPBPs undergo a large, ligand-mediated conformational change that can be linked to reporter functions to monitor ligand concentrations. This mechanism provides the basis of a general system for engineering families of reagentless biosensors that share a common physical signal transduction functionality and detect many different analytes. We demonstrate the facility of designing optical biosensors based on fluorophore conjugates using 8 environmentally sensitive fluorophores and 11 bPBPs specific for diverse ligands, including sugars, amino acids, anions, cations, and dipeptides. Construction of reagentless fluorescent biosensors relies on identification of sites that undergo a local conformational change in concert with the global, ligand-mediated hinge-bending motion. Construction of cysteine mutations at these locations then permits site-specific coupling of environmentally sensitive fluorophores that report ligand binding as changes in fluorescence intensity. For 10 of the bPBPs presented in this study, the three-dimensional receptor structure was used to predict the location of reporter sites. In one case, a bPBP sensor specific for glutamic and aspartic acid was designed starting from genome sequence information and illustrates the potential for discovering novel binding functions in the microbial genosphere using bioinformatics.

Amino Acid Sequence↗
PubMed1991

Fluorescent membrane probes incorporating dipyrrometheneboron difluoride fluorophores.

The spectroscopic properties of a new series of fatty acid analogs in which a dipyrrometheneboron difluoride fluorophore forms a segment of the acyl methylene chain are presented and their characteristics as fluorescent membrane probes are examined. When incorporated as a low mole fraction component in model phospholipid membranes, the probes retain the principal characteristics of the parent fluorophore: green fluorescence emission with high quantum yield, extensive spectral overlap, and low environmental sensitivity. The fluorescence quantum yield is typically two to three times that of comparable membrane probes based on the nitrobenzoxadiazole fluorophore. The spectral overlap results in a calculated Förster energy transfer radius (Ro) of about 57 A. Consequently, increasing fluorescence depolarization and quenching are observed as the mole fraction of the probe species incorporated in the membrane is increased. Low environmental sensitivity is manifested by retention of high quantum yield emission in aqueous dispersions of fatty acids. Partition coefficient data derived from fluorescence anisotropy measurements and iodide quenching experiments indicate that in the presence of fluid phase phospholipid bilayers the aqueous fraction of fatty acid is very small. Fluorescence intensity and anisotropy responses to phospholipid phase transitions are examined and found to be indicative of nonrandom fluorophore distribution in the gel phase. It is concluded that the spectroscopic properties of the fatty acid probes and their phospholipid derivatives are particularly suited to applications in fluorescence imaging of cellular lipid distribution and membrane level studies of lateral lipid segregation.

4-Chloro-7-nitrobenzofurazan↗
PubMed2005

Phosphorylation-driven protein-protein interactions: a protein kinase sensing system.

A highly flexible protein kinase sensing system is described that furnishes severalfold changes in fluorescence in response to phosphorylation. A library of Src kinase peptide substrates was prepared that contained different environmentally sensitive fluorophores positioned at various sites on the active site directed sequence. Robust changes in fluorescent intensity were observed in the presence of a phosphotyrosine binding domain protein (Lck SH2 domain), which furnishes a hydrophobic environment for the fluorophore. This protein kinase sensing system has the advantages that the fluorescent indicator can be unobtrusively positioned on the peptide substrate, and that different environmentally sensitive fluorophores with distinct photophysical properties can be employed.

Aminobutyrates↗
PubMed2002

Homeopathic constitutional type questionnaire correlates of conventional psychological and physical health scales: individual difference characteristics of young adults.

This study examined associations between scores for 19 different remedies on the constitutional type questionnaire (CTQ) and scores on standardized psychological and medical trait and state scales from health psychology research. Subjects were 104 young adult American college students (mean age 20 years; 67% female). Scales included the chemical intolerance index (CII) for environmental sensitivity, the NEO personality inventory, Marlowe-Crowne social desirability (MCSD) Scale for defensiveness, Harvard parental caring scale (HPCS) for perceived mother and father traits, Profile of Mood State (POMS) scale, Pennebaker symptom checklist (PSC), and a 3-item global health rating scale. The majority of CTQ constitutional type scores correlated significantly with greater NEO neuroticism, lower MCSD defensiveness, and greater psychological distress on the POMS subscales. NEO Extraversion and Openness subscales correlated with specific CTQ scores in directions consistent with clinical remedy pictures. CTQ Carcinosin differed from other remedies, showing no significant correlations with other scales. As hypothesized (a) persons high on CTQ scores for Carcinosin and low in parental caring (HPCS) had the highest symptom score; (b) those high on CTQ scores for Sulphur and low on HPCS had the poorest global health ratings; (c) individuals high on four different CTQ type scores (Carcinosin, Lachesis, Nux vomica, Sulphur) and high on environmental sensitivity (CII) exhibited the highest symptom scores. Taken together, the data offer additional validation of the CTQ and provide a foundation for studying interactions of constitutional type with both psychosocial and physicochemical environmental factors in homeopathic provers and patients.

Adult↗