A combined method for determining inhibition type, kinetic parameters, and inhibition coefficients for aerobic cometabolism of 1,1,1-trichloroethane by a butane-grown mixed culture.

A combined method for determining inhibition type, kinetic parameters, and inhibition coefficients is developed and presented. The method was validated by applying it to data obtained from batch kinetics of the aerobic cometabolism of 1,1,1-trichloroethane (1,1,1-TCA) by a butane-grown mixed culture. The maximum degradation rates (k(max)) and half-saturation coefficients (K(s)) were independently determined in single compound tests, and compared with those obtained from inhibition tests. The inhibition type was determined using direct linear plots at various substrate and inhibitor concentrations. Kinetic parameters (k(max) and K(s)) and inhibition coefficients (K(ic) and K(iu)) were determined by nonlinear least squares regression (NLSR) fits of the inhibition model determined from the direct linear plots. Initial guesses of the kinetic parameters for NLSR were determined from linearized inhibition equations that were derived from the correlations between apparent maximum degradation rates (k(app)(max)) and/or the apparent half-saturation coefficient (K(app)(s)) and the k(max), K(s), and inhibitor concentration (I(L)) for each inhibition equation. Two different inhibition types were indicated from the direct linear plots: competitive inhibition of 1,1,1-TCA on butane degradation, and mixed inhibition of 1,1,1-TCA transformation by butane. Good agreement was achieved between independently measured k(max) and K(s) values and those obtained from both NLSR and the linearized inhibition equations. The initial guesses of all the kinetic parameters determined from linear plots were in the range of the values estimated from NLSR analysis. Overall the results show that use of the direct linear plot method to identify the inhibition type, coupled with initial guesses from linearized plots for NLSR analysis, results in an accurate method for determining inhibition types and coefficients. Detailed studies with pure cultures and purified enzymes are needed to further demonstrate the utility of this method.     

Nomencurator: a nomenclatural history model to handle multiple taxonomic views

Evolutionary studies are generating increasing numbers of phylogenies which, in turn, sometimes result in changes to hierarchical organization and therefore changes in taxonomic nomenclature. A three-layered data model for a nomenclature database has been developed in order to elucidate the information structure in nomenclature and as a means to organize and manage a large, dynamic knowledge-base. In contrast to most other taxonomic databases, the model is publication-oriented rather than taxon-oriented and dynamic rather than static, in order to mimic the processes that taxonomists use naturally. The three-layered structure requires data integrity localized to each publication, instead of global data integrity, which relaxes constraints common to taxonomic databases and permits multiple taxonomic opinions: taxon names are made available as metadata within the model. Its prototype implementation, written in C ⁺⁺, has an autonomous self-identification mechanism to avoid spurious data-inflation in a publication-oriented data model. Self-identification is also desirable for distributed implementations of the nomenclature database. Publication-oriented design also will make maintenance easier than for taxon-oriented databases, much of the maintenance workload being amenable to automation. The three-layered data model was designed for use by taxonomists, but is also able to provide concise, reduced expression for non-experts required in biodiversity research, for example.     

Thermophilic bioremediation of whey: effect of physico-chemical parameters on the efficiency of the process

A two-stage process for the bioremediation of blue Stilton whey has been developed. It employs both naturally occurring thermotolerant organisms found in whey (lactic acid bacteria and yeast) and a thermophilic isolate (Bacillus sp.). Thermophilic digestion occurred only at neutral pH. Multiple substrates were consumed simultaneously under mesophilic but not thermophilic conditions.     

A new post-treatment system for anaerobic effluents containing a high Ca2+ content

A novel reactor concept has been developed that combines Ca²⁺ removal and BOD conversion under mesophilic (30 °C ) as well as under thermophilic (55 °C ) conditions. Soluble Ca²⁺, present in many industrial wastewaters, precipitates as a result of forced aeration in the aerobic bioreactor. The CaCO₃ precipitates, in turn, act as a carrier material for biofilm growth. This resulted in dense rapidly settling sludge granules covered with a biofilm on the surface. These sludge characteristics facilitate the application of hydraulic retention times of 1 h while maintaining a high biological activity in the reactor.     

Degradation of 1,3-dichloropropene by a soil bacterial consortium and Rhodococcus sp. AS2C isolated from the consortium

A bacterial consortium capable of degrading the fumigant 1,3-D ((Z)- and (E)-1,3-dichloropropene) was enriched from an enhanced soil. This mixedculture degraded (Z)- and (E)-1,3-D only in the presence of a suitable biodegradable organic substrate, such as tryptone, tryptophan, or alanine. After 8 months of subculturing at 2- to 3-week intervals, a strain of Rhodococcus sp. (AS2C) that was capable of degrading 1,3-D cometabolically in the presenceof a suitable second substrate was isolated. (Z)-3-chloroallyl alcohol (3-CAA) and (Z)-3-chloroacrylic acid (3-CAAC), and (E)-3-CAA and (E)-3-CAAC were the metabolites of (Z)- and (E)-1,3-D, respectively. (E)-1,3-D was degraded faster than (Z)-1,3-D by the strain AS2C and the consortium. AS2C also degraded (E)-3-CAA faster than (Z)-3-CAA. Isomerization of (E)-1,3-D to (Z)-1,3-D orthe (Z) form to the (E) form did not occur.     

THE EFFECT OF AEROBIC TRAINING ON SERUM ADIPONECTIN AND LEPTIN LEVELS AND INFLAMMATORY MARKERS OF CORONARY HEART DISEASE IN OBESE MEN

The aim of this study was to investigate the effect of 12 weeks of aerobic training on the serum levels of adiponectin and leptin and on inflammatory markers of coronary heart disease in obese men. Sixteen non-athlete obese men were randomly assigned to one of two experimental groups. The experimental group underwent aerobic training consisting of three sessions per week for 12 weeks, while the control group did not participate in the training programme during the study period. Five millilitres of venous blood was taken from each participant at the beginning of the study, during week six and at the end of week 12 to measure the levels of leptin, adiponectin, C-reactive protein, interleukin-6 and tumour necrosis factor-α. The findings showed that aerobic training led to decreases in the levels of CRP (P = 0.002), IL-6 (P = 0.001) and leptin (P = 0.003) and an increase in the level of adiponectin (P = 0.002) in the experimental group relative to the control group. In addition, the level of TNF-α decreased in the experimental group after the 12-week aerobic training period, although this change was not statistically significant. According to the results of this study, regular aerobic exercise decreases the potential risk of coronary heart disease by improving the plasma levels of IL-6, adiponectin, leptin and CRP. Additionally, aerobic exercise can be used as effective non-pharmacological treatment to prevent diseases.