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PubMed2003

[Indicators for marine environment: a preliminary application of an integrated approach].

A draft set of indicators was selected to make a state assessment of Italian coastal environment, based upon DPSIR scheme (driving, pressure, state, impact, response), a method which can describe different components of complex environmental systems. The selected indicators are the followings: population and tourism (driving); manufacturing, potential organic loads, trophic loads, maritime transport, fishing fleet, fishing intensity, maricolture (pressure); trophic index TRIX, microbiological quality index IQB (state); bathing water quality (impact); waste water treatment budget, register of sewers, protected areas (response). A brief description is presented for each indicator, in relation to their most important features, construction modalities and environmental meaning.

Environmental Monitoring↗
PubMed1998

A brief history of the mortality and immortality of cultured cells.

During the first half of this century it was believed that because cultured normal cells were immortal, aging must be caused by extracellular events. Thirty-five years ago we overthrough this dogma when we discovered that normal cells do have a limited capacity to divide and that aging occurs intracellularly. We also observed that only cancer cells are immortal. Normal cells are mortal because telomeres shorten at each division. Immortal cancer cells express the enzyme telomerase that prevents shortening. Recently, it was discovered that the telomerase gene when inserted into normal cells immortalizes them. There appears to be a relationship between these findings and aging, longevity determination and cancer. After performing the miracles that take us from conception to birth, and then to sexual maturation and adulthood, natural selection was unable to favor the development of a more elementary mechanism that would simply maintain those earlier miracles forever. This failure is called aging. Because few feral animals age, evolution could not have favored animals exhibiting age changes. Natural selection favors animals that are most likely to become reproductively successful by developing greater survival skills and reserve capacity in vital systems to better survive predation, disease, accidents and environmental extremes. Natural selection diminishes after sexual maturation because the species will not benefit from members favored for greater development of physiological reserve. A species betters its chances of survival by investing its resources and energy in increasing opportunities for reproductive success rather than on post-reproductive longevity. The level of physiological reserve remaining after reproductive maturity determines potential longevity and evolves incidental to the selection process that acts on earlier developmental events. Physiological reserve does not renew at the same rate that it incurs losses because molecular disorder increases. These age changes increase vulnerability to predation, accidents or disease.

Animals↗
PubMed2000

The evolution of recombination in a heterogeneous environment.

Most models describing the evolution of recombination have focused on the case of a single population, implicitly assuming that all individuals are equally likely to mate and that spatial heterogeneity in selection is absent. In these models, the evolution of recombination is driven by linkage disequilibria generated either by epistatic selection or drift. Models based on epistatic selection show that recombination can be favored if epistasis is negative and weak compared to directional selection and if the recombination modifier locus is tightly linked to the selected loci. In this article, we examine the joint effects of spatial heterogeneity in selection and epistasis on the evolution of recombination. In a model with two patches, each subject to different selection regimes, we consider the cases of mutation-selection and migration-selection balance as well as the spread of beneficial alleles. We find that including spatial heterogeneity extends the range of epistasis over which recombination can be favored. Indeed, recombination can be favored without epistasis, with negative and even with positive epistasis depending on environmental circumstances. The selection pressure acting on recombination-modifier loci is often much stronger with spatial heterogeneity, and even loosely linked modifiers and free linkage may evolve. In each case, predicting whether recombination is favored requires knowledge of both the type of environmental heterogeneity and epistasis, as none of these factors alone is sufficient to predict the outcome.

Alleles↗
PubMedDate not supplied

How and why we age.

After performing the miracles that takes us from conception to birth, and then to sexual maturation and adulthood, natural selection was unable to favor the development of a more elementary mechanism that would simply maintain those earlier miracles forever. The manifestations of this failure are called aging. Because few feral animals age, evolution could not have favored a genetic program for age changes. Natural selection favors animals that are most likely to become reproductively successful by developing better survival strategies and greater reserve capacity in vital systems to better escape predation, disease, accidents, and environmental extremes. Natural selection diminishes after reproductive success because the species will not benefit from members favored for greater longevity. The level of physiological reserve remaining after reproductive maturity determines longevity and evolves incidental to the selection process that acts on earlier developmental events. Physiological reserve does not renew at the same rate that it incurs losses because molecular disorder increases at a rate greater than the capacity for repair. These are age changes, and they increase vulnerability to predation, accidents, or disease. Failure to distinguish aging from disease has not only blurred our efforts to understand the fundamental biology of aging, but it has profound political and economic consequences that compromise the field of biogerontology. Changes attributable to disease, or pathological change, can be distinguished from age changes for at least four important reasons. Unlike any known disease, (1) age changes occur in every human given sufficient time, (2) age changes cross virtually all species barriers, (3) no disease afflicts all members of a species only after the age of reproductive success, and (4) aging occurs in all feral animals subsequently protected by humans, even when that species probably has not experienced aging for thousands or millions of years. The resolution of age-associated diseases will not advance our knowledge of aging, just as the resolution of the diseases of childhood did not advance our knowledge of childhood development. We have failed to convey that greater support must be given to a question that is rarely posed. It is a question that is applicable to all age-associated diseases, and its resolution will also advance our fundamental knowledge of aging: "Why are old cells more vulnerable to pathology and disease than are young cells?" During the first half of this century it was believed that because cultured normal cells were immortal, aging must be caused by extra-cellular events. Thirty-five years ago we overthrough this dogma when we found that normal cells do have a limited capacity to divide, and that age changes can occur intracellularly. We also observed that only abnormal or cancer cells are immortal. Normal cells are mortal because telomeres shorten at each division. Immortal cancer cells express the enzyme telomerase that prevents shortening. Recently, it was discovered that when the catalytic subunit of the telomerase gene is inserted into normal cells they become immortal.

Aging↗
PubMed2001

Microbial inhibitors for U.S. EPA drinking water methods for the determination of organic compounds.

Preservation of chemical analytes in drinking water samples is necessary to obtain accurate information concerning contaminant occurrence. Sample preservation to prevent biodegradation is important for most samples and analytes. With the unique demands of environmental methods, it is not always possible to kill all microorganisms without having undesirable effects. To find a suitable preservative, the sample, analysis, and preservation needs should be considered. During method development of U.S. Environmental Protection Agency (EPA) Methods 526 (for unstable semivolatile compounds) and 532 (for phenylurea pesticides), a number of studies were conducted to identify compatible microbial inhibitors. Copper sulfate was successfully used in Method 532 and is an excellent first-choice antimicrobial agent for many applications. Copper sulfate can catalyze hydrolysis reactions for some pesticides such as those analyzed in Method 526. Under these conditions, a nonmetal compound of antimicrobial activity must be considered. During the development of Method 526, a survey of alternate organic based antimicrobial compounds found that diazolidinyl urea worked well in the method. Several other candidate microbial inhibitors were identified that could have application to other environmental methods. A general approach to selecting antimicrobial compounds in future environmental methods in water matrixes is discussed.

Anti-Infective Agents, Local↗
PubMed2005

ADH enzyme activity and Adh gene expression in Drosophila melanogaster lines differentially selected for increased alcohol tolerance.

In Drosophila melanogaster, alcohol dehydrogenase (ADH) activity is essential for ethanol tolerance, but its role may not be restricted to alcohol metabolism alone. Here we describe ADH activity and Adh expression level upon selection for increased alcohol tolerance in different life-stages of D. melanogaster lines with two distinct Adh genotypes: Adh(FF) and Adh(SS). We demonstrate a positive within genotype response for increased alcohol tolerance. Life-stage dependent selection was observed in larvae only. A slight constitutive increase in adult ADH activity for all selection regimes and genotypes was observed, that was not paralleled by Adh expression. Larval Adh expression showed a constitutive increase, that was not reflected in ADH activity. Upon exposure to environmental ethanol, sex, selection regime life stage and genotype appear to have differential effects. Increased ADH activity accompanies increased ethanol tolerance in D. melanogaster but this increase is not paralleled by expression of the Adh gene.

Adaptation, Physiological↗
PubMedDate not supplied

Epidemiology of acute promyelocytic leukemia.

BACKGROUND: The estimated incidence of acute promyelocytic leukemia (APL) is approximately 6 cases per 10 million people per year with no apparent differences between sexes. The age of APL cases is younger than that of other acute myeloid leukemias (AML). Spatial and temporal clusters of APL have been reported. These observations suggest a possible selective role for environmental and/or occupational factors in APL development. METHODS: A multicenter case-control study was carried out on risk factors for acute leukemias and preleukemias. In this report data related to APL are selectively analyzed from the larger study to identify specific risk factors. RESULTS: The case-control study on 38 cases of APL showed a strong association with shoemaking (odds ration 6.3, 95% confidence interval 1.3-31.1). A moderate leukemogenic effect from living in houses built with tuff, a polous building material containing gamma-emitting radionuclides and having a high radon concentration, and from using hair dyes was also suggested. CONCLUSIONS: These data, together with the reported spatial and temporal clustering of APL, support the hypothesis of specific environmental and/or occupational risk factors for APL among other AML subtypes and indicate the need for additional ad hoc multicenter studies.

Adolescent↗
PubMed2004

[Determination of fluorine in the environmental samples by combustion-hydrolysis-ion selective electrode method].

OBJECTIVE: To establish a fast and accurately method of determination of fluorine in coal, hair and food by combustion-hydrolysis-ion selective electrode method. METHODS: The influence factors on combustion-hydrolysis, such as silica weight, temperature and time of hydrolysis, sample weight and volume of distilled water were studied so that to determine the best of all testing conditions. RESULTS: The time for hydrolysis in this method was reduced by one third of that of GB/T4633-1997 standard of PRC method. The fluorine in standard reference material such as tea, poplar leaves, coal and capsicum, and corn was determined on precision and accuracy by this method. The relative standard deviation was less than 5%. The recovery varied from 90.3% to 107.6%. CONCLUSION: The method is suitable for determining fluorine in the various environmental samples.

Carbon↗
PubMed2000

The antecedents of psychoses: a case-control study of selected risk factors.

Winter birth, urban birth and/or childhood residence, and perinatal complications have each been identified as environmental risk factors for the later development of schizophrenia, schizoaffective disorder, and bipolar disorder. A preliminary case-control study also identified cat exposure in childhood as a possible risk factor. To assess selected environmental events, including childhood exposure to pets, as possible risk factors for these diseases, a case-control telephone survey was carried out by the University of Maryland Survey Research Center for 264 mothers of cases and 528 mothers of matched controls. The cases were randomly selected mothers who were members of the National Alliance for the Mentally Ill, and whose children had been diagnosed with schizophrenia, schizoaffective disorder, or bipolar disorder. The controls were mothers randomly selected from the same telephone exchanges. For five of the 19 major variables, there were statistically significant differences between cases and controls: fever during pregnancy, complications during delivery, city or suburban residence at birth, cat ownership between birth and age 13, and breast-feeding. In a multivariate logistic regression including these five variables, each variable made a significant contribution. The finding of perinatal complications, urban/suburban residence at birth, and cat ownership in childhood as risk factors for the later development of psychoses confirmed previous studies. Previous research on breast-feeding as a risk factor has yielded contradictory results. Additional research is needed to ascertain how such environmental risk factors interact with genetic risk factors. Understanding these could lead to better treatments and possible prevention strategies.

Adolescent↗
PubMed2004

Tebuconazole dissipation and metabolism in Tifton loamy sand during laboratory incubationt.

The fungicide tebuconazole is widely used to control soil-borne and foliar diseases in peanuts and other crops. No published data are currently available on the extent and rate at which this compound degrades in soil. Unpublished data summarized in registration documents suggest that the compound is persistent, with 300-600 days half-life. We conducted a 63-day laboratory incubation to evaluate tebuconazole's dissipation kinetics and impact on soil microbial activity in Tifton loamy sand. Tifton soils support extensive peanut production in the Atlantic Coastal Plain region of Georgia and Alabama. Products containing tebuconazole are applied to an estimated 50% of the peanut acreage in the region. At the end of the incubation, 43 (+/-42)% of the parent compound was recovered in soil extracts. The first-order kinetic model, which gave a good fit to the dissipation data (r2 = 0.857), yielded a soil half-life (t1/2) of 49 days. This is 6-12 times more rapid than t1/2 values described in unpublished tebuconazole registration documents. Four degradates were identified. Tentative structural assignments indicated that degradates were derived from hydroxylation of the parent compound and/or chlorophenyl ring cleavage. Cleavage products showed a steady increase during the incubation, and on a molar basis were equal to 63% of the time zero tebuconazole concentration. No significant effect on soil microbial biomass was observed, indicating that when the compound is applied at normal agronomic rate it does not impact soil metabolic activity. Use of the soil-half life data derived in this study should improve the accuracy oftebuconazole fate assessments for Coastal Plain peanut production. The study also indicated that environmental assessment of selected degradates may be needed to fully evaluate risks of tebuconazole use.

Biodegradation, Environmental↗
PubMed2000

Agonist-induced conformational changes at the cytoplasmic side of transmembrane segment 6 in the beta 2 adrenergic receptor mapped by site-selective fluorescent labeling.

The environmentally sensitive, sulfhydryl-reactive, fluorescent probe N,N'-dimethyl-N-(iodoacetyl)-N'-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) ethylene-diamine (IANBD) was used as a molecular reporter of agonist-induced conformational changes in the beta(2) adrenergic receptor, a prototype hormone-activated G protein-coupled receptor. In the background of a mutant beta(2) adrenergic receptor, with a minimal number of endogenous cysteine residues, new cysteines were introduced in positions 269(6.31), 270(6.32), 271(6.33), and 272(6.34) at the cytoplasmic side of transmembrane segment (TM) 6. The resulting mutant receptors were fully functional and bound both agonists and antagonist with high affinities also upon IANBD labeling. Fluorescence spectroscopy analysis of the purified and site-selectively IANBD-labeled mutants suggested that the covalently attached fluorophore was exposed to a less polar environment at all four positions upon agonist binding. Whereas evidence for only a minor change in the molecular environment was obtained for positions 269(6.31) and 270(6.32), the full agonist isoproterenol caused clear dose-dependent and reversible increases in fluorescence emission at positions 271(6.33) and 272(6.34). The data suggest that activation of G protein-coupled receptors, which are activated by "diffusible" ligands, involves a structural rearrangement corresponding to the cytoplasmic part of TM 6. The preferred conformations of the IANBD moiety attached to the inserted cysteines were predicted by employing a computational method that incorporated the complex hydrophobic/hydrophilic environment in which the cysteines reside. Based on these preferred conformations, it is suggested that the spectral changes reflect an agonist-promoted movement of the cytoplasmic part of TM 6 away from the receptor core and upwards toward the membrane bilayer.

Adrenergic beta-Agonists↗
PubMed1997

A nitrite microsensor for profiling environmental biofilms.

A highly selective liquid membrane nitrite microsensor based on the hydrophobic ion-carrier aquocyanocobalt(III)-hepta(2-phenylethyl)-cobrynate is described. The sensor has a tip diameter of 10 to 15 (mu)m. The response is log-linear in freshwater down to 1 (mu)M NO(inf2)(sup-) and in seawater to 10 (mu)M NO(inf2)(sup-). A method is described for preparation of relatively large polyvinyl chloride (PVC)-gelled liquid membrane microsensors with a tip diameter of 5 to 15 (mu)m, having a hydrophilic coating on the tip. The coating and increased tip diameter resulted in more sturdy sensors, with a lower detection limit and a more stable signal than uncoated nitrite sensors with a tip diameter of 1 to 3 (mu)m. The coating protects the sensor membrane from detrimental direct contact with biomass and can be used for all PVC-gelled liquid membrane sensors meant for profiling microbial mats, biofilms, and sediments. Thanks to these improvements, liquid membrane sensors can now be used in complex environmental samples and in situ, e.g., in operating bioreactors. Examples of measurements in denitrifying, nitrifying, and nitrifying/denitrifying biofilms from wastewater treatment plants are shown. In all of these biofilms high nitrite concentrations were found in narrow zones of less than 1 mm.

Journal Article↗
PubMed1999

[A brief overview of the discovery of cell mortality and immortality and of its influence on concepts about aging and cancer].

After having accomplished the miraculous performance that led us from conception to birth, then to sexual maturity and adulthood, natural selection failed to develop a more elementary mechanism capable of simply maintaining the results of this process forever. This failure is aging. Because few animals age in the wild, evolution could not give an advantage to animals with modifications due to aging. Natural selection benefits those animals that have the highest likelihood of effectively perpetuating their species because their vital systems have the larger reserve capacity they need to resist and survive predators, disease, injury, and extreme environmental conditions. Natural selection decreases after sexual maturity has been reached because at that stage the species would not derive additional advantages from individuals with larger physiological reserves. A species increases its likelihood of survival by investing its resources and energy into increasing its opportunities for fruitful reproduction rather than into prolonging its postreproductive life span. Most animals are mortal and undergo aging because investment of resources into keeping the body eternally youthful does not promote species survival as much as their investment into strategies that make reproduction more successful.

Aging↗
PubMed1996

Induction effects of polychlorinated biphenyls, polycyclic aromatic hydrocarbons and other widespread aromatic environmental pollutants on microsomal monooxygenase activities in chick embryo liver.

Cytochrome P450-dependent 7-ethoxyresorufin O-deethylase (EROD), 7-pentoxyresorufin O-dealkylase (PROD) and 7-ethoxycoumarin O-deethylase (ECOD) activities in 14-day-old chick embryo livers were determined 24 h after pretreatment with selected widespread aromatic environmental contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), hexachlorobenzene, and dialkylesters of phthalic acid, and compared with the inducing potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the coplanar and mono-o-chlorinated PCBs. The effects of other model inducers, i.e. phenobarbital and pyrazole, were also examined. Specificity of EROD induction was estimated with regard to contaminants frequently present in environmental samples and dose-response curves for EROD induction were determined. A strong induction (comparable with that by mono-o-chlorinated biphenyl treatment) by dibenzo[a,h]anthracene, benzo[k]fluoranthene or benzo[b]fluoranthene was found, but the maximal level of EROD activity inducible by TCDD was not achieved, partly due to the high toxicity of the tested PAHs. 3-Methylcholanthrene showed moderate inducing potencies; benz[a]anthracene, benzo[a]pyrene, chrysene and 2,2',3,4,4',5'-hexachlorobiphenyl appeared to be weak inducers. Other PAHs and PCBs tested, as well as hexachlorobenzene, dialkyl phthalates, phenobarbital and pyrazole had no marked effects on the EROD level. ECOD activities were increased non-specifically by TCDD, 3-methylcholanthrene, hexachlorobenzene and phenobarbital. A significant enhancement of PROD activity by TCDD and related inducers was observed, while phenobarbital induced the PROD activity only weakly; SDS-PAGE analysis showed that the chicken phenobarbital-inducible cytochromes P4502H with apparent molecular weights 50 kDa were not markedly induced by the TCDD- or 3-methylcholanthrene treatments. Inhibition of EROD and PROD by 9-hydroxyellipticine, a specific inhibitor of rat hepatic cytochrome P4501A1, revealed that PROD induction by TCDD and other P4501A-inducers was probably a result of a broader substrate specificity of chick embryo P4501A. Measurement of EROD activities in chick embryo liver is highly sensitive, specific and suitable for the determination of TCDD-type toxicity of new drugs, agrochemicals, and industrial pollutants.

7-Alkoxycoumarin O-Dealkylase↗
PubMed2005

Biogeochemistry of carbonates: recorders of past oceans and climate.

Trace metal proxies bound within the calcium carbonate tests of oceanic organisms provide a unique insight into how the climate system works on timescales which span eight orders of magnitude, from annual to hundreds of millions of years. Whilst the motivation for developing these proxies was the idea that thermodynamic equilibria control the chemistry during precipitation, in reality the application of trace metal proxies relies upon empirical calibration. Such calibration can be applied to a wide range of environmental reconstructions, but more accurate application of proxies requires a mechanistic understanding of the biomineralization process. The partitioning of trace metals into biogenic carbonates reflects to some extent the same pattern as an inorganic crystal, but there is an additional selectivity and differing environmental sensitivity to, e.g., temperature, which confirms that biochemical processes also play a role in the uptake and assembly of ions into a crystal. Different organisms display differing degrees of biological control on their carbonate chemistry. Aragonitic coral chemistry is most similar to inorganic precipitation from seawater whilst coccolithophores are most different, and these contrasts correlate with the degree of control of the organism over its biomineralization. Selectivity between Ca and trace metals during biomineralization arises during transport by pumps, channels, or nucleation upon an organic matrix. The biological selectivity of the transporters and matrix is strikingly similar in its base chemistry to the selective assembly of ions into a crystal. In each case, the selectivity between Ca2+ and trace metals derives from the balance between the energy required for dehydration of the hexaaqua complex of the cation, and the energy released from the new coordination geometry of binding with either carbonyl oxygen from polysaccharides or amino acids, or carbonate oxygen in the crystal. This is a speculative idea, but with some careful chemical calculations based on the energy of binding of Ca2+ or the trace metal ions to these macromolecular structures, it provides an alternative thermodynamic framework within which to consider the application of trace metal proxies.

Animals↗
PubMed1999

[Aging in parts? Systemic aging of the nervous system].

Neurons of the central nervous system in general do not multiply after birth. Therefore, no replacement or biological renewal of individual cells affected by aging or death is possible. Morphological changes occurring in the aging brain are found substantially more pronounced in neurodegenerative diseases. Systemic degenerations of selective brain areas in these disorders, e.g. in Alzheimer's, Parkinson's, Huntington's disease or in amyotrophic lateral sclerosis, may be considered as models of accelerated aging and may allow to study the genetic and environmental influences of selective aging and cell death in modules of the central nervous system. Although neurodegenerative diseases are disparate disorders on the basis of their symptomatology and the anatomic distribution of pathologic lesions, they actually share key attributes with respect to biochemical and cellular determinants of selective vulnerability. Most strikingly, many show a conversion of disease specific and only recently identified proteins into unsoluble aggregates which form intra- or extracellular deposits. These protein aggregates may, over time, affect neuronal function, eventually leading to neurodegeneration and neurodegenerative pathology. The pathological process is counterbalanced by protective mechanisms that may loose their efficacy during normal aging. This could explain the late onset of even the inherited neurodegenerative disorders. Since the expression of disease-specific proteins is often not restricted to the affected brain areas (as exemplified by the expression of polyglutamine containing proteins in trinucleotide repeat disorders in non-affected brain areas and even outside the brain), the anatomical specificity of the degenerative process may be determined by associated binding proteins. Therapeutic strategies include the reinforcement of physiological defense mechanisms and intervention at early phases of the pathological biochemistry of disease specific proteins.

Animals↗
PubMed2003

Life cycle economic and environmental implications of using nanocomposites in automobiles.

By reducing the energy and materials required to provide goods and services, nanotechnology has the potential to provide more appealing products while improving environmental performance and sustainability. Whether and how soon this potential could be realized depends on phrasing the right research and development (R&D) questions and pursuing commercialization intelligently. A sufficiently broad perspective at the outset is required to understand economic and technical feasibility, estimate life cycle environmental implications, and minimize unanticipated negative impacts. The rapid rise in federally funded nanotechnology R&D dictates that consideration of societal benefits will have a large role in setting the R&D agenda. We estimate potential selected economic and environmental impacts associated with the use of nanotechnology in the automotive industry. In particular, we project the material processing and fuel economy benefits associated with using a clay-polypropylene nanocomposite instead of steel or aluminum in light-duty vehicle body panels. Although the manufacturing cost is currently higher, a life cycle analysis shows potential benefits in reducing energy use and environment discharges by using a nanocomposite design.

Conservation of Energy Resources↗