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At least 469 records · Page 26Linked to original sources
PubMed2002

[Quantitative analysis of genetic parameters in populations of European (Capreolus capreolus L.) and Siberian (Capreolus pygargus Pall.) roe deer with RAPD markers].

A technique for obtaining unbiased estimates of genetic parameters (allelic frequencies of RAPD loci, heterozygosity (H), Wright's F statistic, and Nei's genetic distances) in populations of the European (Capreolus capreolus L.) and Siberian (Capreolus pygargus Pall.) roe deer is presented. The technique employs jackknifing and multiple comparative analysis based on a modified Holmes's procedure for Bonferroni's test. It was demonstrated that samples from local groups of roe deer in the Trans-Ural region did not differ significantly in allelic frequencies (0.8, 0.81, and 0.78; P > 0.447) or Nei's genetic distances (0.0056, 0.0273, and 0.0218; P = 0.26), but they could be differentiated based on Wright's F statistic (0.0346, 0.0519, and 0.0450; P = 10(-9)). The parameters of intrapopulation heterozygosity (from 0.18 to 0.042) formed a gradient from the east to the west. Calibration estimates of molecular evolution rate in the family Cervidae obtained based on published data and Jukes-Cantor genetic distances estimated in this study demonstrated that the Siberian roe deer has split into two subspecies, C. pygargus pygargus Pall. and C. pygargus tianschanicus Satunin in the interval between 229 and 462.3 thousand years ago. The species formation of the Siberian and European roe deer was dated between 1.375 and 2.75 Myr ago. Based on the results obtained we recommend the approaches used in the study for analysis of population genetic structure and phylogenetic relationships between populations, subspecies, species, and higher taxa.

Animals↗
PubMed2003

[Physicochemical changes and maturity evaluation of solid organic waste compost].

Composting is one of the most effective ways for recycling of organic solid waste. Various characteristics of different kinds of organic solid waste cause various physicochemical changes during composting, as well as the different composting conditions. Stability and maturity evaluation are the measurement for compost quality and the safe guarantee for its agricultural utilization. Stability evaluation of compost focuses on the impacts to environment after its agricultural utilization, while maturity evaluation pays attention on the phytotoxicity to plant. Stability and maturity of compost are affected by several factors, such as the characteristics of raw materials, the composting condition, and so on. Stability could be assessed by compost temperature, color, evolution rate of CO2, consumption rate of O2, content of NO3(-)-N and quantities of pathogen, etc. Temperature was suggested to be one of the most convenient parameters for stability evaluation. Maturity could be assessed by various parameters, including the chemical, biological, and phytotoxical parameters. Seed germination index, as the phytotoxical parameter, was recommended to be one of the most convenient and reliable parameters of maturity evaluation.

Conservation of Natural Resources↗
PubMed2004

Coupling pH-stat and DO-stat titration to monitor degradation of organic substrates.

A combined titration methodology at constant pH and dissolved oxygen concentration to monitor the degradation of organics as carbon dioxide evolution rate (CER) and oxygen uptake rate (OUR) is presented. Equations necessary to assess CER from alkali titration rates and the instrument used to test the technique are described. Experiments were performed on samples of activated sludge from a domestic wastewater treatment plant using glucose and ethanol as substrates. OUR and CER were calculated for both substrates, as well as the respiratory quotient RQ = CER/OUR and biomass to substrate yields coefficients. RQ data for ethanol compared better with corresponding stoichiometric values than those for glucose.

Biodegradation, Environmental↗
PubMed2004

Workflow improvement and impact of the new Beckman Coulter LH 1500 high throughput automated hematology workcell.

Our core laboratory at St. Joseph's Medical Center (SJMC) recently installed the new Beckman Coulter LH 1500 fully automated hematology workcell. Like many laboratories in North America and other parts of the world, we are under significant pressure to improve productivity, reduce costs, and improve service provision to our hospital and clinician bases. The difficulty of meeting this challenge is often further compounded by an increasing shortage of qualified technologist personnel. We recently reported on the significant productivity gains with the introduction of the LH 750 hematology system into the core laboratory, including a 23% reduction in slide review rate, automation of reticulocyte and nucleated red blood cell counts, and an 82% increase in the pass-through rate. Evolution to the next stage of automation has come much quicker than anticipated owing to a steep rise in workload and an ever increasing shortage of trained and experienced technologists to fill vacancies in the 24-hour core laboratory operation. We chose to upgrade our LH 750 analyzers to the newly introduced LH 1500 hematology workcell in order to cope with the increased workload and shortage of available experienced hematology technologists. The LH 1500 is a compact, high throughput, fully automated hematology workcell. It is designed to automate all manual process and handling steps associated with hematology analyses, including sample sorting, loading and unloading of cassettes, automatic rerun and reflex testing, sample storage, and tracking of samples. The LH 1500 is comprised of a minimum of 2, and up to 4, LH 750 instruments (with or without integrated slidemaker/stainers). The instruments are bidirectionally interfaced and linked to a fully automated conveyor track, specimen inlet and outlet stations, a sample stockyard, and a line controller. The configuration we chose at SJMC incorporates 1 LH 750 and 1 LH 755. We report that the upgrade to the LH 1500 was a relatively straightforward process and required no redesign of the core laboratory. Based on our evaluation, we estimate cost savings with the LH 1500 of between three quarters to 1 full-time equivalent, which eliminated or decreased many manual handling steps. In addition, this increase in efficiency has freed up our technologist resources to concentrate on the more difficult and clinically important samples. This is the first published report on the new LH 1500 hematology workcell. Our research indicates that the LH 1500 is the first hematology workcell to offer hematology laboratories the next level of automation and virtually eliminate preanalytical and postanalytical sample handling and sorting. For core laboratories and high-throughput hematology laboratories that face similar pressures to ours, the LH 1500 would appear as an attractive solution to maximize hematology productivity and improve service delivery.

Automation↗
PubMed2004

Processing dewatered sewage sludge using electrokinetic technology.

High content of heavy metals and presence of pathogens in the dewatered sewage sludge have been the main obstacles for land application of sewage sludge-made fertilizer. The aim of this study was to examine the effects of the innovative electrokinetic (EK) technology on removal of heavy metals from sewage sludge, on the reduction of pathogens, and on sludge chemical characteristics. The results showed that the removal efficiencies for Zn, Cu, Ni, Cr, As and Pb were 94.9%, 95.4%, 89.7%, 67.8%, 31.2% and 18.7%, respectively. Acidification pretreatment of the dewatered sludge for 29 h decreased the content of heterotrophic bacteria from 1.5 x 10(8) c.f.u./g of wet sludge to 1.1 x 10(4) c.f.u./g of wet sludge. Although the initial content of total coliforms and fecal coliforms in sewage sludge were 5.8 x 10(5) c.f.u./g of wet sludge and 4.0 x 10(5) c.f.u./g of wet sludge, respectively, no viable cells were detected. Minor losses of K and N were detected, but the loss of P was found to be significant in EK treated sewage sludge. The treated sludge was technically considered as very stable based on the carbon dioxide evolution rate.

Bioreactors↗
PubMed2003

[Phylogenetic relationships among the genera of Taxodiaceae and Cupressaceae from 28S rDNA sequences].

DNA sequences from 28S rDNA were used to assess relationships between and within traditional Taxodiaceae and Cupressaceae s.s. The MP tree and NJ tree generally are similar to one another. The results show that Taxodiaceae and Cupressaceae s.s. form a monophyletic conifer lineage excluding Sciadopitys. In the Taxodiaceae-Cupressaceae s.s. monophyletic group, the Taxodiaceae is paraphyletic. Taxodium, Glyptostrobus and Cryptomeria forming a clade(Taxodioideae), in which Glyptostrobus and Taxodium are closely related and sister to Cryptomeria; Sequoia, Sequoiadendron and Metasequoia are closely related to each other, forming another clade (Sequoioideae), in which Sequoia and Sequoiadendron are closely related and sister to Metasequoia; the seven genera of Cupressaceae s.s. are found to be closely related to form a monophyletic lineage (Cupressoideae). These results are basically similar to analyses from chloroplast gene data. But the relationships among Taiwania, Sequoioideae, Taxodioideae, and Cupressoideae remain unclear because of the slow evolution rate of 28S rDNA, which might best be answered by sequencing more rapidly evolving nuclear genes.

English Abstract↗
PubMed2005

[Expression and characterization of FNRD in cyanobacterium Synechococcus sp. PCC 7002].

The petHL genes under the control of Lac and Kan promoters were transformed into Synechococcus sp. PCC 7002, respectively. Both of the petHL genes are integrated into the cyanobacterium chromosomes, which is inferred from the results of Southern blot analysis. Western blot analysis results show that both petHL genes are expressed in the transformed cells, and Kan promoter is more effective than Lac promoter. The FNRD in vivo shows the same stability as that of FNR holoenzyme. Some FNRD molecules are probably acylated as judged by the result of Triton X-114 phase partition test. FNRD in vivo might act as a component in photosynthetic electron transport chain, which increases the photosynthetic oxygen evolution rate.

Blotting, Southern↗
PubMedDate not supplied

[Immunodiffusion analysis of plasma proteins in the canine family].

Immunodiffusion studies have been made on the plasma of 9 species (Vulpes vulpes, V. corsak, Alopex lagopus, Canis aureus, C. lupus, C. familiaris, C. dingo, Nyctereutes procynoides, Fennecus zerde) from the family of Canidae using milk antisera. Unlike rabbit antisera used earlier, milk antisera make it possible to detect more significant antigenic divergency with respect to 5 alpha- and beta-globulins. These globulins seem to have a higher evolution rate of antigenic mosaics as compared to other plasma proteins in the family investigated. The family Canidae serologically may be divided into two main groups: 1) the genus Canis which includes the wolf, domestic dog, dingo, jackal and 2) species which significantly differ from the former (the fox, polar fox, dog fox, fennec). In relation to these two groups, the raccoon dog occupies special position.

Animals↗
PubMedDate not supplied

[Quantitative study of biological denitrification in soil with the aid of acetylene. I.--Application on different soils (author's transl)].

The use of acetylene for investigation about biological denitrification in soils requires study of intensity and persistence of N2O-reductase activity inhibition by this gas and the effects on the other stages of denitrification and on the general metabolism of microflora. The methodology used is described, taking into account N2O solubility. N2O-evolution rates from nitrite and nitrate were measured during long-term incubations under acetylene, and complete inhibition of N2O-reductase was observed. After 2 weeks, acetylene inhibition appears decreased. The nitrate reduction rate seems increased in the presence of acetylene.

Acetylene↗
PubMed1995

The effects of donor and recipient endotoxemia on TNF alpha production and mortality in the rat model of syngenic orthotopic liver transplantation.

The effects of administration of endotoxin to donors or recipients on the mortality rate, evolution of endotoxin levels, and tumor necrosis factor alpha (TNF-alpha) release were investigated in a syngenic orthotopic liver transplantation model in Lewis rats with portal reperfusion only. No significant recipient endotoxemia, TNF-alpha release, or mortality occurred in control recipients following transplantation from normal donors. The doses of endotoxin needed to kill 50% and 100% of animals after hepatic artery ligation were, respectively, 4 mg/kg and 10 mg/kg. Transplantation of animals' livers with no preservation phase from donors who were administered a lethal dose of endotoxin for this combination (10 mg/kg) produced significant recipient endotoxemia at 10 min (6.9 +/- 2.5 x 10(3) endotoxin unit/ml (EU/ml), P < 0.01), 45 min (8.8 +/- 1.1 x 10(3) EU/ml, P < 0.001) and 8 hr (18.5 +/- 3.5 x 10(3) EU/ml, P < 0.001) after graft reperfusion. Significant levels of TNF-alpha were also detected in these animals at 45 min (280 +/- 70 pg/ml, P < 0.007) and 8 hr (80 +/- 40 pg/ml, P < 0.05) when compared with the controls. Mortalities in recipients of OLT from donor animals that had received endotoxin (2 mg/kg or 4 mg/kg) immediately prior to the harvesting procedure was 0% and 20%, respectively, compared with no death in the control group. When recipient animals were administered endotoxin immediately after graft reperfusion the resistance to endotoxin administration was significantly reduced compared with animals that had not received OLT (LD50 < 2 mg/kg versus 4 mg/kg; LD100 4 mg/kg versus 10 mg/kg, respectively). These results show that endotoxin and its effects can be transferred from the liver graft donor to the recipient and that OLT per se reduces the recipient resistance to endotoxin with subsequent increase in mortality.

Animals↗
PubMed1995

Preparation and characteristics of magnetite-labelled antibody with the use of poly(ethylene glycol) derivatives.

With a view to the application of magnetic particles in cancer thermotherapy (hyperthermia), methods of preparing a bio-applicable magnetite with targeting activity towards cancer cells were investigated, and the properties of the material examined. Poly(ethylene glycol) (PEG)-magnetite consisting of magnetite (Fe3O4) and PEG with terminal carboxy or amino groups was prepared. Monoclonal antibody was then immobilized covalently on to the PEG-magnetite. Among three different immobilization methods employed, the highest immobilization density of 492 mg of protein/g of PEG-magnetite was achieved by using water-soluble carbodi-imide. However, with respect to residual antibody activity, only the method in which IgG sugar chains were oxidized to give aldehyde groups for coupling to N-terminal PEG-magnetite was satisfactory, with about 60% of the activity surviving. The immobilization density by this method (109 mg of protein/g of PEG-magnetite) was also sufficiently high. The product, termed magnetite-labelled antibody, was of sub-micrometre size and showed easy magnetophoresis. It was further elucidated that cancer-specific magnetite-labelled antibody bound to cancer cells at an amount of 50 mg of magnetite/cm3 of cells. The PEG-magnetite generates heat at an evolution rate of 31.5 W/g, and the amount adsorbed to the cells was calculated to be high enough to heat a tumour 1 cm in diameter to more than 42 degrees C in 30 s under an alternating magnetic field [at an intensity of 572 Oe (approx. 45.5 kA/m) and a frequency of 240 kHz]. This magnetite-labelled antibody is expected to be applicable clinically as a therapeutic agent for the induction of hyperthermia.

Antibodies, Monoclonal↗
PubMed1994

Effects of Cu(II) complexes on photosynthesis in spinach chloroplasts. Aqua(aryloxyacetato)copper(II) complexes.

The inhibitory effect of 14 aqua(aryloxyacetato) copper(II) complexes on oxygen evolution rate in spinach chloroplasts has been investigated. The inhibitory effect of these effectors on photosynthesis was confirmed by Hill reaction as well as by EPR and fluorescence spectroscopies. The results of the EPR study showed that the sites of action of the studied effectors are Z+ and Y+ intermediates at the donor side of the photosystem (PS) 2. The EPR study also showed that another site of action is the oxygen evolving complex, namely its manganese cluster. The above suggestions were supported by the results of the fluorescence study as well. Based on the restoring of the photosynthetic electron transport to 2,6-dichlorophenol-indophenol in chloroplasts inhibited by the studied Cu(II) complexes using sym-diphenylcarbazide it can be assumed that the own core of PS2 (P680) and a part of the electron transport chain-at least up to plastoquinone-remain intact.

Chloroplasts↗
PubMed1996

Concentration-dependent inhibitory and stimulating effects of amphiphilic ammonium salts upon photosynthetic activity of spinach chloroplasts.

The effects of piperidinopropylesters of 2-, 3- and 4-alkoxy substituted phenylcarbamic acids (PPACs) on oxygen evolution rate (OER) in spinach chloroplasts were investigated. PPAGs show concentration-dependent effects, namely OER inhibition at higher effector concentrations and OER stimulation at lower concentrations, i.e. below the inhibitory concentration range. The inhibitory efficiency of PPACs showed dependence on the alkyl chain length of the alkoxy substituent as well as on the position of this substituent on the benzene ring. Using EPR spectroscopy and fluorescence measurements it was confirmed that the site of PPAC inhibitory action is the donor side of photosystem 2, where D1 and D2 proteins are situated, namely the intermediates Z+/Y+, and the manganese cluster containing protein as well. The stimulating effects of PPACs on OER in spinach chloroplasts at relatively low effector concentrations are caused by photophosphorylation uncoupling due to protonophore properties of the effectors.

Binding Sites↗
PubMed2001

Improvement of tagatose conversion rate by genetic evolution of thermostable galactose isomerase.

To enhance the isomerization rate of galactose into tagatose, a thermostable galactose isomerase, which was isolated from bacteria growing in a hot spring, was genetically improved using the error-prone PCR method. From 500 mutant clones, a clone showing improved conversion activity was selected. The sequence of the selected clone had five amino acid changes: His(228)-->Asp, Gly(384)-->Asp, Ser(393)-->Thr, Lys(428)-->Asn and Asp(475)-->Lys. The improved galactose isomerase had an 11-fold higher reaction rate than the original.

Aldose-Ketose Isomerases↗
PubMed2000

Estimating the rate of molecular evolution: incorporating non-contemporaneous sequences into maximum likelihood phylogenies.

MOTIVATION: TipDate is a program that will use sequences that have been isolated at different dates to estimate their rate of molecular evolution. The program provides a maximum likelihood estimate of the rate and also the associated date of the most recent common ancestor of the sequences, under a model which assumes a constant rate of substitution (molecular clock) but which accommodates the dates of isolation. Confidence intervals for these parameters are also estimated. RESULTS: The approach was applied to a sample of 17 dengue virus serotype 4 sequences, isolated at dates ranging from 1956 to 1994. The rate of substitution for this serotype was estimated to be 7.91 x 10(-4) substitutions per site per year (95% confidence intervals of 6.07 x 10(-4), 9.86 x 10(-4)). This is compatible with a date of 1922 (95% confidence intervals of 1900-1936) for the most recent common ancestor of these sequences. AVAILABILITY: TipDate can be obtained by WWW from http://evolve.zoo. ox.ac.uk/software. The package includes the source code, manual and example files. Both UNIX and Apple Macintosh versions are available from the same site.

DNA, Viral↗
PubMed1998

Body size effects and rates of cytochrome b evolution in tube-nosed seabirds.

Variation in rates of molecular evolution now appears to be widespread. The demonstration that body size is correlated with rates of molecular evolution suggests that physiological and ecological factors may be involved in molecular rate variation, but large-scale comparative studies are still lacking. Here, we use complete cytochrome b sequences from 85 species of tube-nosed seabirds (order Procellariiformes) and 5 outgroup species of penguins (order Sphenisciformes) to test for an association between body mass and rates of molecular evolution within the former avian order. Cladistic analysis of the 90 sequences estimates a phylogeny largely consistent with the traditional taxonomy of the Procellariiformes. The Diomedeidae, Procellariidae, and Pelecanoididae are monophyletic, while the Hydrobatidae are basal and paraphyletic. However, the two subfamilies within the Hydrobatidae (Hydrobatinae and Oceanitinae) are monophyletic. A likelihood ratio test detects significant deviation from clocklike evolution in our data. Using a sign test for an association between body mass and branch length in the seabird phylogeny, we find that larger taxa tend to have shorter terminal branch lengths than smaller taxa. This observation suggests that rates of mitochondrial DNA evolution are slower for larger taxa. Rate calibrations based on the fossil record reveal concordant body size effects. We interpret these results as evidence for a metabolic rate effect, as the species in this order exhibit large differences in metabolic rates, which are known to be highly correlated with body mass in this group. Our results support previous findings of body size effects and show that this effect can be significant even within a single avian order. This suggests that even lineage-specific molecular clocks may not be tenable if calibrations involve taxa with different metabolic rates.

Age Factors↗
PubMed1994

Disparate rates of molecular evolution in cospeciating hosts and parasites.

DNA sequences for the gene encoding mitochondrial cytochrome oxidase I in a group of rodents (pocket gophers) and their ectoparasites (chewing lice) provide evidence for cospeciation and reveal different rates of molecular evolution in the hosts and their parasites. The overall rate of nucleotide substitution (both silent and replacement changes) is approximately three times higher in lice, and the rate of synonymous substitution (based on analysis of fourfold degenerate sites) is approximately an order of magnitude greater in lice. The difference in synonymous substitution rate between lice and gophers correlates with a difference of similar magnitude in generation times.

Animals↗
PubMed1996

The rate of compensatory evolution.

A two-locus model is presented to analyze the evolution of compensatory mutations occurring in stems of RNA secondary structures. Single mutations are assumed to be deleterious but harmless (neutral) in appropriate combinations. In proceeding under mutation pressure, natural selection and genetic drift from one fitness peak to another one, a population must therefore pass through a valley of intermediate deleterious states of individual fitness. The expected time for this transition is calculated using diffusion theory. The rate of compensatory evolution, kappa c, is then defined as the inverse of the expected transition time. When selection against deleterious single mutations is strong, kappa c becomes independent on the recombination fraction r between the two loci. Recombination generally reduces the rate of compensatory evolution because it breaks up favorable combinations of double mutants. For complete linkage, kappa c is given by the rate at which favorable combinations of double mutants are produced by compensatory mutation. For r > O, kappa c decreases exponentially with r. In contrast, kappa c becomes independent of r for weak selection. We discuss the dynamics of evolutionary substitutions of compensatory mutants in relation of WRIGHT's shifting balance theory of evolution and use our results to analyze the substitution process in helices of mRNA secondary structures.

Evolution, Molecular↗