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S P Cummings

Publications and source records attributed to S P Cummings.

10 recordsLinked to original sources
PubMed2006

The impact of bioaugmentation on metal cyanide degradation and soil bacteria community structure.

Metal cyanides are significant contaminants of many soils found at the site of former industrial activity. In this study we isolated bacteria capable of degrading ferric ferrocyanide and K2Ni(CN)4. One of these bacteria a Rhodococcus spp. was subsequently used to bioaugment a minimal medium broth, spiked with K2Ni(CN)4, containing 1 g of either an uncontaminated topsoil or a former coke works site soil. Degradation of the K2Ni(CN)4 was observed in both soils, however, bioaugmentation did not significantly impact the rate or degree of K2Ni(CN)4 removal. Statistical analysis of denaturing gradient gel electrophoresis profiles showed that the topsoil bacterial community had a higher biodiversity, and its structure was not significantly affected by either K2Ni(CN)4 or bioaugmentation. In contrast, profiles from the coke works site indicated significant changes in the bacterial community in response to these additions. Moreover, in both soils although bioaugmentation did not affect rates of biodegradation the Rhodococcus spp. did become established in the communities in broths containing both top and coke works soil. We conclude that bacterial communities from contaminated soils with low biodiversity are much more readily perturbed through interventions such as contamination events or bioaugmentation treatments and discuss the implications of these findings for bioremediation studies.

Cyanides↗
PubMed2006

The application of the herbicide bromoxynil to a model soil-derived bacterial community: impact on degradation and community structure.

AIMS: Bromoxynil degradation by soil micro-organisms has been shown to be co-oxidative in character. In this study, we investigate both the impact of the application of increasing bromoxynil concentrations on soil-derived bacterial communities and how these changes are reflected in the degradation of the compound. Our aim was to test the hypothesis that the addition of bromoxynil to a soil-derived bacterial community, and the availability of a readily utilizable carbon source would have an impact on bromoxynil degradation, and that would be reflected in the bacteria present in the soil community. METHODS AND RESULTS: Degradation of bromoxynil was observed in soil-derived communities containing 15 mg l(-1), but not 50 mg l(-1) of the compound, unless glucose was added. This suggests that the addition of carbon stimulates co-oxidative bromoxynil degradation by the members of the bacterial community. Measurable changes in the bacterial community indicated that the addition of bromoxynil led to deterministic selection on the bacterial population, i.e. the communities observed arise through the selection of specific micro-organisms that are best adapted to the conditions in the soil. The addition of bromoxynil was also shown to have a negative impact on the presence of alpha and gamma-proteobacteria in the soil community. CONCLUSION: Bromoxynil degradation is significantly inhibited in bacterial soil communities in the absence of readily accessible carbon. The application of bromoxynil appears to exert deterministic selection on the bacterial community. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlights the effects of increasing bromoxynil concentrations on a model bacterial population derived from soil. Soil communities show qualitative and quantitative differences to bromoxynil application depending on the availability of organic carbon. These findings might have implications for the persistence of bromoxynil in agricultural soils.

Bacteria↗
PubMed2001

Potassium uptake and retention by Oceanomonas baumannii at low water activity in the presence of phenol.

Oceanomonas baumannii(T) (ATCC 700832) is a halotolerant bacterium capable of degrading phenol, which requires potassium in order for turgor growth to occur in minimal medium containing 5% NaCl (w/v). However, at this salinity growth can be inhibited by reduced potassium concentrations. The affinity for potassium (K(S)) was determined to be 219 microM and 408 microM for cultures utilising phenol and succinate respectively as the sole carbon source for growth. Rubidium but not caesium could substitute for potassium in alleviating growth inhibition due to potassium limitation. The effect of elevated phenol on potassium retention was studied, and it was shown that contrary to expectations, as external phenol concentration was increased the levels of intracellular potassium were significantly elevated. This observation correlated with changes in the cytoplasmic membrane, particularly the increase in the saturated:unsaturated fatty acid ratio from 0.47 to 1.44, and the decrease in the zwitterionic:anionic phospholipid ratio from 2.23 to 1.22. Both these changes promote membrane bilayer configurations and increase lipid ordering of the membrane reducing its permeability and inhibiting cation efflux.

Cell Membrane↗
PubMed2001

Reclassification of [Pseudomonas] doudoroffii (Baumann et al. 1983) into the genus Oceanomonas gen. nov. as Oceanomonas doudoroffii comb. nov., and description of a phenol-degrading bacterium from estuarine water as Oceanomonas baumannii sp. nov.

A bacterium, isolate GB6T, capable of degrading phenol in the presence of elevated salinity was isolated from the estuary of the River Wear, UK. The bacterium was subjected to biochemical and molecular analysis to determine its taxonomic status. These studies indicated that the bacterium was a distinct species closely related to [Pseudomonas] doudoroffii. However, the phylogenetic analysis indicated that [Pseudomonas] doudoroffii was misclassified, as noted previously. Analysis of the characteristics of isolate GB6T and the type strain of [Pseudomonas] doudoroffii confirmed that these bacteria belonged to the same novel genus, which we have named Oceanomonas gen. nov. The type strain of Oceanomonas doudoroffii (Baumann et al. 1983) comb. nov. is ATCC 27123T (= DSM 7028T. The DNA-DNA homology between isolate GB6T and [Pseudomonas] doudoroffii is low and phenotypic differences between the two organisms are evident. Isolate GB6T (= ATCC 700832T = NCIMB 13685T) is therefore proposed as the type strain of a new species, Oceanomonas baumannii sp. nov.

Bacterial Typing Techniques↗
PubMed2001

Flavobacterium frigidarium sp. nov., an aerobic, psychrophilic, xylanolytic and laminarinolytic bacterium from Antarctica.

A psychrophilic, aerobic bacterium designated A2iT was isolated from marine sediment recovered from shallow waters surrounding Adelaide Island, Antarctica (67 degrees 34' S, 68 degrees 07' W). The organism exhibited xylanolytic and laminarinolytic activity and was halotolerant. Basic characterization showed that it was gram-negative, non-motile, yellow-pigmented (beta,beta-carotene-3,3'-diol) and positive for oxidase and catalase synthesis. Analysis of the 16S rDNA sequence suggests that the organism belongs to the Flexibacter-Cytophaga-Bacteroides phylum. On the basis of its 16S rDNA sequence, the bacterium is 96.8% similar to Flavobacterium columnare ATCC 43622--its closest relation. The genomic DNA G+C content was 35 mol%. Growth on xylan occurs optimally at 15 degrees C, though growth also occurs at 0 degrees C, and the doubling times are 9.6 and 34.8 h, respectively. The maximum growth temperature on xylan is at 24 degrees C. The bacterium is a neutrophile, growing across the pH range 5.6-8.4 and having an optimum at pH 7.5. Analysis of the 16S rDNA sequence, together with phenotypic characterization, suggests that the organism is a member of the genus Flavobacterium. DNA-DNA hybridization experiments have shown that it is a novel species; it is proposed, therefore, that the organism be designated as the type strain of Flavobacterium frigidarium sp. nov. (= ATCC 700810T = NCIMB 13737T).

Aerobiosis↗
PubMed2000

The modification of the membrane of Oceanomonas baumannii when subjected to both osmotic and organic solvent stress.

Oceanomonas baumanniioff a novel halotolerant bacterium which was isolated from the estuary of the river Wear (Sunderland, UK). When grown in tryptone soya broth it can tolerate high levels of phenol, which is not utilised as a carbon source in this medium. However, the level of tolerance was reduced from 35 mM to 3 mM phenol as salinity increased from 1% to 12% NaCl (w/v). Increasing salinity up to 12% NaCl also decreased the growth rate 8-fold and caused modifications to the cytoplasmic membrane particularly anionic phosphatidylglycerol levels, which doubled at the expense of zwitterionic phosphatidylethanolamine. In addition, changes in the phospholipid fatty acid composition were noted, cis-vaccenic acid decreased significantly at higher salinities. Intracellular solute levels also increased with increasing salinity and there was an accumulation of the compatible solutes ectoine, glycine betaine and glutamate. The addition of phenol to osmotically compromised cultures led to a further modification of the cytoplasmic membrane phospholipid composition, in particular, that the decrease in zwitterionic phosphatidylethanolamine and the increase of anionic phospholipid species was much less pronounced. A further decrease in unsaturation, particularly in the proportion of cis-vaccenic acid, and the mean chain length of the fatty acids suggested that this response was important in maintaining membrane integrity in the presence of phenol.

Cell Membrane↗
PubMed1999

Polymer hydrolysis in a cold climate.

In this review we discuss the activity of an ecologically significant group of psychrophilic bacteria, which are involved in the hydrolysis of plant cell wall polymers. Until now these organisms have been largely overlooked, despite the key role they play in releasing organic carbon fixed by primary producers in permanently cold environments such as Antarctica. This review details a specific group of plant cell wall polymer-degrading enzymes known as beta-glycanases. Studies on "cold" enzymes in general are in their infancy, but it has been shown that many exhibit structural and functional modifications that enable them to function at low temperature. beta-Glycanases in particular are intriguing because their substrates (cellulose and xylan) are very refractile, which may indicate that their "cold" modifications are pronounced. In addition, mesophilic beta-glycanases have been extensively studied and the current state of our knowledge is reviewed. This body of information can be exploited to enable meaningful comparative studies between mesophilic and psychrophilic beta-glycanases. The aim of such investigations is to obtain a deeper insight into those structural and functional modifications that enable these enzymes to function at low temperature and to examine the evolutionary relationship between mesophilic and psychrophilic beta-glycanases.

Adaptation, Physiological↗
PubMed1992

Successful treatment of postoperative chylothorax using an external pleuroperitoneal shunt.

We report 3 patients with chylothorax who were successfully managed as outpatients using external pleuroperitoneal shunts. This external shunt has the advantage over subcutaneously placed shunts of pumping large volumes of fluid with each compression of the pumping chamber, of not causing the discomfort associated with pumping a subcutaneous chamber, of not becoming difficult to find in the subcutaneous space, and of being constructed of larger components which do not kink or become easily clogged with fibrinous debris.

Adult↗
PubMed1990

Colonic leiomyoma--an unusual cause of gastrointestinal hemorrhage in childhood. Report of a case.

Leiomyomas of the intestine are rarely found in the pediatric population. The authors' review of the literature revealed only three colonic leiomyomas previously described. The authors present the first reported case of a child with lower gastrointestinal hemorrhage secondary to a colonic leiomyoma. Pathologic aspects of intestinal leiomyomas are discussed along with the difficulty in histologic differentiation from leiomyosarcomas. Wide resection is recommended for spindle cell neoplasms of the intestine owing to difficulty in differentiating benign from malignant tumors.

Child↗