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PubMed1986

Phenotypic characteristics of coliform and noncoliform bacteria from a public water supply compared with regional and national clinical species.

During the summer and fall of 1984, elevated total coliform counts were observed in the distribution system of a public water supply serving 350,000 people in south central Connecticut. As part of an investigation of possible health risks associated with the presence of bacteria in the water supply, bacterial isolates from the distribution system were compared with bacterial isolates of the same species obtained from a large regional teaching hospital and from a national compendium of clinical isolates. Characteristics analyzed included phenotypic metabolic activity, antimicrobial susceptibilities to clinically utilized antibiotics, temperature tolerance at 44.5 degrees C, and beta-glucuronidase activity in single-test form and on a selective medium. Environmental isolates lacked known plasmid-mediated characteristics, with the exception of one Escherichia coli isolate which showed some antibiotic resistance. Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, and Enterobacter agglomerans from all sources were temperature tolerant and yielded positive fecal coliform tests. Only E. coli showed beta-glucuronidase activity (both in a single biochemical test and on a selective medium). No single characteristic analyzed was sufficient to establish an organism as either environmental or clinical in origin.

Anti-Bacterial Agents↗
PubMed2001

Comparison of selective media for the detection of Vibrio vulnificus in environmental samples.

AIMS: To compare two selective agars, cellobiose-colistin (CC) agar and a modification of the Vibrio vulnificus medium (VVMc agar), for the isolation of Vibrio vulnificus from environmental samples. METHODS AND RESULTS: The efficiencies of recovery of V. vulnificus collection strains on CC, VVM, VVMc and on thiosulphate-citrate-bile salts-sucrose (TCBS) agar were compared and similar efficiencies were obtained. A slightly higher recovery was observed on VVMc agar. The detection of V. vulnificus in environmental samples (eels and water) was performed by combining culture-based methods (CC and VVMc agars) with DNA-based methods using species-specific probes based on the cytolysin-haemolysin and the 16S rDNA genes. A lower accompanying microbiota was found on CC agar than on VVMc agar. CONCLUSION: The comparison between CC and VVMc agars confirms that both are useful for the detection of V. vulnificus in environmental samples. However, the use of any of these media should be combined with a species-specific probe. SIGNIFICANCE AND IMPACT OF THE STUDY: The combined use of a selective medium and a specific probe provides a feasible method for the detection of V. vulnificus for epidemiological and ecological studies.

Cell Culture Techniques↗
PubMed2001

Environmental challenges in computer manufacturing.

The purpose of this research is to examine the environmental policies and programs that have been instituted by four large computer manufacturers. These environmental concerns, while not highly publicized, present an extremely important challenge to computer manufacturers, as well as to our society in general. Though the environmental programs of these computer manufacturers have been in place for several years, the topic of environmental health and safety (EHS) in computer manufacturing is still a relatively new one. Four major computer manufacturers that have instituted environmental programs are selected in this research. Their environmental policies and programs are examined in detail and compared with each other to show the relative strength and weakness. The result of this research highlights that with the amazing growth of computer use for both business and in our daily life, it will only be a matter of time before the issue -- the environmental challenges in computer manufacturing -- gains prominence and exposure in our society on a large-scale basis.

Computers↗
PubMed1998

The effects of environmental conditions on the in vitro activity of selected antimicrobial agents against Escherichia coli.

Various environmental conditions likely to be encountered at a nidus of infection were evaluated for their effect on selected classes of antimicrobial agents. The minimum inhibitory concentration (MIC) of several aminoglycosides (apramycin, kanamycin, gentamicin, tobramycin, amikacin), tetracycline, and chloramphenicol for five strains of E. coli were unchanged by temperature (35 degrees-39.5 degrees C), atmosphere (aerobic to anaerobic), pH > 7, NaCl concentration (up to 150 mM), zinc concentration (up to 50 mM), and manganese (up to 10 mM). However, the aminoglycoside MICs were increased up to fivefold at pH < 6.5. Magnesium and calcium ion concentrations >10 mM and ferric iron concentrations >/=10 mM increased aminoglycoside MICs from 3.66- to 8-fold. Tetracycline MICs were increased 1.2- to 6.5-fold when the concentration of magnesium or calcium was >/=10 mM. The results of this in vitro study might provide insight into the effects of local in vivo environmental conditions on several classes of antimicrobial agents.

Anti-Bacterial Agents↗
PubMed1999

Analysis of a continuous-culture technique for the selection of mutants tolerant to extreme environmental stress.

An analysis is presented of a continuous-culture technique named "Brown and Oliver Interactive-Continuous Selection" (BOICS; Brown and Oliver, 1982), that was devised for the selection of microbial mutants tolerant to extreme environmental stress. The case in which the stress is due to a growth inhibitor is considered. The possible steady outcomes of competition between mutants in BOICS are analyzed under the assumption that the specific growth rates of the competing mutants depend only on the inhibitor concentration. The analysis indicates that BOICS selects mutants that sustain a given specific growth rate (equal to the dilution rate in the selection experiment) at an increased concentration of the inhibitor. Simulation results support the steady-state analysis. Further simulation results show that BOICS may fail if the specific growth rate of a mutant has to be considered to depend on a factor beside the inhibitor concentration. The choice of experimental conditions that promote the success of BOICS is discussed. An interpretation of BOICS emerges from the analysis. Namely, that BOICS implements (at least approximately) a strategy for the selection of tolerant mutants in which (1) all factors in the growth environment, beside the stress of interest (inhibitor concentration) are maintained constant, and (2) the stress is adjusted as the culture evolves so that it is always maximized subject to a specified minimum value of the mean specific-growth rate being maintained. This interpretation suggests new (possibly improved) ways of implementing essentially the same selection technique. It is noted that a chemostat implements the same strategy in the case that the stress is due to the lack of a growth-rate-limiting nutrient. The outcome of selection for inhibitor tolerant mutants in chemostats, turbidostats, and in BOICS is compared. Only BOICS selects specifically for mutants tolerant to extreme concentrations of the inhibitor.

Adaptation, Physiological↗
PubMed2005

Monitoring the bacterial population dynamics during fermentation of artisanal Argentinean sausages.

The dynamics of the microbial community responsible for the artisanal fermentation of dry sausage produced in Argentina was investigated by using classical and molecular approaches. The combined use of RAPD analysis with primers M13, XD9, RAPD1 and RAPD2 and 16S rDNA sequencing were applied to the identification and intraspecific differentiation of 100 strains of lactobacilli and Micrococcaceae. DGGE analysis was used to monitor the dynamic changes in population after total microbial DNA was directly extracted from sausages and subjected to PCR using V3f (GC), Bact-0124f-GC and Univ-0515r primers. The sequence analysis of 16S rDNA of the dominant species was also carried out. Lactobacillus sakei and Lactobacillus plantarum were the dominant lactic acid organisms during the fermentation while Staphylococcus saprophyticus represented the dominant species of Micrococcaceae. It was demonstrated that the ripening process of Argentinean artisanal fermented sausage is driven by a limited number of Lactobacillus and Staphylococcus strains selected from environmental microbiota by the ability to best compete under the prevailing conditions of the ecological niche. The identification of dominant communities present in this artisanal fermented sausage can help in the selection of starter cultures consisting in well adapted strains to the particular production technology.

Animals↗
PubMed2005

Evolution of the environmental component of the phenotypic variance: stabilizing selection in changing environments and the cost of homogeneity.

Quantitative traits show abundant genetic, environmental, and phenotypic variance, yet if they are subject to stabilizing selection for an optimal phenotype, both the genetic and environmental components are expected to decline. The mechanisms that determine the level and maintenance of phenotypic variance are not yet fully understood. While there has been extensive study of mechanisms maintaining genetic variability, it has generally been assumed that environmental variance is not dependent on the genotype and therefore not subject to change. However, accumulating data suggest that the environmental variance is under some degree of genetic control. In this study, it is assumed accordingly that both the genotypic value (i.e., mean phenotypic value) and the variance of phenotypic value given genotypic value depend on the genotype. Two models are investigated as potentially able to explain the protected maintenance of environmental variance of quantitative traits under stabilizing selection. One is varying environment among generations, such that both the optimal phenotype and the strength of the stabilizing selection vary between generations. The other is the cost of homogeneity, which is based on an assumption of an engineering cost of minimizing variability in development. It is shown that a small homogeneity cost is enough to maintain the observed levels of environmental variance, whereas a large amount of temporal variation in the optimal phenotype and the strength of selection would be necessary.

Analysis of Variance↗
PubMed2000

Biracial Japanese American identity: an evolving process.

This qualitative study explored the complexity of biracial identity development in Japanese Americans. It is based on the constant comparable method of analysis, or grounded theory. The study focused on how Japanese Americans perceived themselves in relation to other individuals, groups, and their environment. The data consisted of 15 extensive semistructured interviews with 8 men and 7 women (ages 20 to 40 years), each with 1 Japanese parent and 1 non-Asian parent. Findings relate to participants' initiating explorations of identity and perseverance in pursuing a biracial identity, which depended on the degree of support or negative experience within their social networks. Participants explored identity options attempting to develop their own meaning of identity, to develop a confident sense of themselves, and to secure a positive ethnic identity. Identity development among participants varied. It was a long-term process involving changes in the individual-environment relationship, which differed in the way individual participants influenced or selected from environmental opportunities, even creating or recreating some aspects. Within a given setting, as youths, the potential for social experiences were relatively fixed and changed only gradually. As adults, there were opportunities for participants to select their own social and geographic settings, providing opportunity for change. In their new environments, participants were exposed to new contacts and role models, acquired new behavioral repertoire, and underwent role transitions. Depending on this, new and different aspects of biracial identity developed. Participants indicated it was an emotional and conflictual process to positive assertion of identity. Before reaching this, all of the participants experienced periods of confusion. Most asserted biracial identity gradually, through a process of racial identity development consisting of the individual's changing or maintaining certain reference group perspectives, identifications, and allegiances as they passed through a series of life experiences. Instead of staying marginalized, they integrated both cultures, recognizing positive values of both, thus developing an integrated identity. Although the participants' experiences and perceptions were varied, the overarching themes of self-evaluation, confusion of categorization, belonging, infusion/exploration, situational use of identity, and resolution/acceptance/self-verification were presented. On the basis of the research, a model of ethnic identity for biracial individuals is proposed.

Adaptation, Psychological↗
PubMed2005

Asthma and air pollution in the Bronx: methodological and data considerations in using GIS for environmental justice and health research.

This paper examines methods of environmental justice assessment with Geographic Information Systems, using research on the spatial correspondence between asthma and air pollution in the Bronx, New York City as a case study. Issues of spatial extent and resolution, the selection of environmental burdens to analyze, data and methodological limitations, and different approaches to delineating exposure are discussed in the context of the asthma study, which, through proximity analysis, found that people living near (within specified distance buffers) noxious land uses were up to 66 percent more likely to be hospitalized for asthma, and were 30 percent more likely to be poor and 13 percent more likely to be a minority than those outside the buffers.

Adolescent↗
PubMed2004

Life cycle assessment of mobile phone housing.

The life cycle assessment of the mobile phone housing in Motorola(China) Electronics Ltd. was carried out, in which materials flows and environmental emissions based on a basic production scheme were analyzed and assessed. In the manufacturing stage, such primary processes as polycarbonate molding and surface painting are included, whereas different surface finishing technologies like normal painting, electroplate, IMD and VDM etc. were assessed. The results showed that housing decoration plays a significant role within the housing life cycle. The most significant environmental impact from housing production is the photochemical ozone formation potential. Environmental impacts of different decoration techniques varied widely, for example, the electroplating technique is more environmentally friendly than VDM. VDM consumes much more energy and raw material. In addition, the results of two alternative scenarios of dematerialization showed that material flow analysis and assessment is very important and valuable in selecting an environmentally friendly process.

Conservation of Energy Resources↗
PubMed2006

Microbial diversity in hypersaline wastewater: the example of tanneries.

In contrast to conventional wastewater treatment plants and saline environments, little is known regarding the microbial diversity of hypersaline wastewater. In this study, the microbial communities of a hypersaline tannery effluent, and those of three treatment systems operating with the tannery effluent, were investigated using 16S rDNA phylogenetic markers. The comparative analysis of 377 bacterial sequences revealed the high diversity of this type of hypersaline environment, clustering within 193 phylotypes (> or = 97% similarity) and covering 14 of the 52 divisions of the bacterial domain, i.e. Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Chlorobi, Planctomycetes, Spirochaetes, Synergistes, Chloroflexi, Thermotogae, Verrucomicrobia, OP3, OP11 and TM7. Most of the phylotypes were related to halophilic and pollutant-degrading bacteria. Using statistical analysis, the diversity of this type of environment was compared to that of other environmental samples selected on the basis of their salinity, oxygen content and organic load.

Bacteria↗
PubMed1980

Independent effects of the pineal and a bacterial pyrogen in behavioural thermoregulation in lizards.

The pineal complex of lizards is comprised of an extracranial photoreceptive structure known as the parietal eye, and an intracranial pineal organ which is homologous to the pineal gland of birds and mammals. Studies have shown that removing the parietal eye or severing the parietal nerve causes lizards to select higher temperatures when allowed to thermoregulate behaviourally in thermal or photothermal laboratory gradients. Although comparable studies involving removal of the lizard pineal organ have not previously been attempted, field data indicate that pinealectomy may have an antagonistic effect to parietalectomy. We present evidence here which shows that (1) following pinealectomy, collared lizards (Crotaphytus collaris) behaviourally select or prefer lower temperatures than their controls in thermal laboratory gradients, and (2) the effect of surgical treatment is independent of the effects of a behavioural fever-inducing substance which elevates by a fixed amount the environmental temperatures selected.

Animals↗
PubMed2006

Extracellular hippocampal acetylcholine level controls amygdala function and promotes adaptive conditioned emotional response.

Ample data indicate that tone and contextual fear conditioning differentially require the amygdala and the hippocampus. However, mechanisms subserving the adaptive selection among environmental stimuli (discrete tone vs context) of those that best predict an aversive event are still elusive. Because the hippocampal cholinergic neurotransmission is thought to play a critical role in the coordination between different memory systems leading to the selection of appropriate behavioral strategies, we hypothesized that this cholinergic signal may control the competing acquisition of amygdala-mediated tone and contextual conditioning. Using pavlovian fear conditioning in mice, we first show a higher level of hippocampal acetylcholine release and a specific pattern of extracellular signal-regulated kinase 1/2 (ERK1/2) activation within the lateral (LA) and basolateral (BLA) amygdala under conditions in which the context is a better predictor than a discrete tone stimulus. Second, we demonstrate that levels of hippocampal cholinergic neurotransmission are causally related to the patterns of ERK1/2 activation in amygdala nuclei and actually determine the selection among the context or the simple tone the stimulus that best predicts the aversive event. Specifically, decreasing the hippocampal cholinergic signal not only impaired contextual conditioning but also mimicked conditioning to the discrete tone, both in terms of the behavioral outcome and the LA/BLA ERK1/2 activation pattern. Conversely, increasing this cholinergic signal not only disrupted tone conditioning but also promoted contextual fear conditioning. Hence, these findings highlight that hippocampal cholinergic neurotransmission controls amygdala function, thereby leading to the selection of relevant emotional information.

Acetylcholine↗
PubMedDate not supplied

Adults with traumatic brain injury: three case studies of cognitive rehabilitation in the home setting.

This article discusses the use of occupational therapy in the home setting and the individual application of treatment methods. Three case studies are presented that involve adults with acquired brain injury with memory deficits. The treatment methods used were (a) saturational cuing with behavioral chaining and positive reinforcement, (b) a coordinated team approach incorporating family or significant others and other therapists, and (c) environmental adaptations. A decision-making model and the dynamic assessment approach were used as a framework for treatment planning. The treatment technique chosen depended on the skill to be learned and the patient's learning style. Each case required the selection of environmental adaptations including (a) use of family and attendants as cotherapists; (b) a tape-recorded message, played daily; and (c) an appointment book for daily things to do. Each case demonstrated prolonged therapy for skill acquisition with this patient population.

Adult↗
PubMed2000

The ecology and genetics of fitness in Chlamydomonas. IX. The rate of accumulation of variation of fitness under selection.

Populations of Chlamydomonas founded by single cells were cultured in chemostats for 50 days, representing about 125 generations. The mean and variance of division rate was measured daily by withdrawing cells from the effluent and culturing them for 24 h on filtered effluent medium solidified with agar. Mean fitness did not change during the period of culture, and the behavior of neutral markers indicated that no substitutions of novel beneficial mutations occurred. However, the variance of fitness increased markedly at about the same rate in two replicate populations. The standardized rate, or mutational heritability, was Vm/VE = 4-5 x 10(-3) per generation. This is substantially greater than most other estimates for characters closely correlated with fitness. Moreover, it seems difficult to reconcile with the absence of any change in mean fitness. We investigated the possibility that frequency-dependent selection was created by spatial heterogeneity within the culture vessel by testing cell populations with different phenotypes from the top, bottom, and surface of the chemostats. However, the differentiation of these populations seemed to be attributable to phenotypic plasticity, with no evidence that their characteristics were heritable. Finally, we report an experiment in which lines were selected for about 100 generations on solid or liquid medium. These lines became specifically adapted to the medium on which they were cultured, showing that liquid and solid media, even when chemically identical, provide different conditions of growth for Chlamydomonas. The genetic variance appearing in the cultures was therefore attributed to conditionally neutral mutations that were not expressed in the chemostat. This implies that rates of accumulation of mutational variance measured in the culture environment itself (where this can be done) may greatly underestimate the variation available for a response through selection to environmental change. Moreover, it suggests that chemostat populations may be more dynamic and more diverse than is usually thought.

Animals↗
PubMed2004

Aerobic oxidation of 2,3,6-trimethylphenol to trimethyl-1,4-benzoquinone with copper(II) chloride as catalyst in ionic liquid and structure of the active species.

TMQ is an important precursor in industrial vitamin E synthesis. We report a "green chemistry approach" with respect to the highly selective and environmentally friendly oxidation of 2,3,6-trimethylphenol (TMP) to trimethyl-1,4-benzoquinone (TMQ) with molecular oxygen as oxidant and a copper catalyst immobilized in a molten salt. n-Butanol as co-solvent has a positive effect on the activity and selectivity. The structurally characterized catalyst, a 1-n-butyl-3-methylimidazolium oxotetracuprat, is formed in situ via hydrolysis of CuCl2 in the presence of imidazolium chloride. We propose a mechanism of oxidative phenolate activation at a [Cu4(mu4-O)]6+ core as electronically coupled electron acceptor, formation of a copper-bound phenolate radical anion, spin delocalization into the aromatic ring, and attack by triplet oxygen at the para position. Attack of Cu(I) as reduction equivalent at the peroxy radical, proton-mediated elimination of a copper(II)-hydroxo species, will either substitute a copper(I) site in the reduced oxo cluster or take up an electron from the reduced mixed valent cluster [Cu4(mu4-O)]6+ to regenerate the oxidized cluster as the active electron acceptor.

Benzoquinones↗
PubMed2026

Co-occurrence of biofilm formation, acid tolerance, and antibiotic resistance in environmental Escherichia coli associated with lettuce.

BACKGROUND: Environmental niches represent important reservoirs of Escherichia coli with stress-adaptation traits that support persistence outside the host. Contaminated irrigation water and soils can facilitate transfer to fresh produce, where bacterial survival may reduce the effectiveness of downstream control measures. This study investigated the co-occurrence of biofilm formation, acid tolerance, and antibiotic resistance (AR) in environmental E. coli and their contribution to persistence along the farm-to-produce continuum. RESULTS: Eighteen E. coli isolates recovered from irrigation water, soil, and lettuce were characterized using phenotypic assays and genome-based analyses. Most isolates remained susceptible to the majority of tested antibiotics, with multidrug resistance observed in only 11.1% of isolates. In contrast, moderate-to-strong biofilm formation was widespread (83.3%), and several isolates exhibited reduced susceptibility to acetic acid at concentrations relevant to household washing practices. Genotypic screening revealed a broad distribution of adhesion, iron acquisition, biofilm-associated, and plasmid-borne resistance determinants, indicating substantial functional diversity. Significant positive associations were observed between acid tolerance, biofilm formation, and antibiotic resistance, suggesting co-occurrence of stress-adaptation phenotypes rather than definitive evolutionary convergence. While antibiotic resistance phenotypes showed strong concordance with corresponding resistance genes, biofilm formation and acid tolerance were not associated with specific genetic determinants, supporting a multifactorial basis of these traits. CONCLUSIONS: These findings demonstrate that environmental E. coli can combine multiple stress-adaptation mechanisms that enhance persistence across agricultural and food-associated environments, even in the absence of high-risk resistance profiles. The observed co-occurrence of phenotypic traits highlights the potential for co-selection under environmental pressures and underscores the limitations of relying solely on downstream decontamination strategies. Effective risk mitigation requires integrated, preventive approaches targeting pre-harvest contamination and environmental reservoirs.

Biofilms↗