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PubMed1984

Determination of trace elements of Egyptian cane sugar (Naga Hammady factories) by neutron activation, atomic absorption spectrophotometric and inductively coupled plasma-atomic emission spectrometric analyses.

INAA, AAS and ICP-AES techniques are applied to the determination of trace amounts of Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Eu, Fe, Ga, Hf, K, La, Li, Lu, Mg, Mn, Na, Nb, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Th, Ti, U, V, W and Zn in the stalks of sugar cane plant after extracting juice, raw juice principal (mixed) juice, juice withdrawn from the successive stages of sugar industry, sirup, deposits from evaporators, molasse, A-? and B-sugar and in the soil samples (collected from the field supplying the factories by cane plants) taken from the immediate vicinity of the plant roots at surface, 30 and 60 cm depth. The results obtained are in a good agreement of the safety baselines of using juice as beverage, molasse derivatives (honey, sweets, ...) as diet for common people in the developed countries and in industry (methanol, ethanol, acetone & acetic acid, ...) and sugar sweeting for many purposes (in beverages, desserts, ...). Differences of trace elements concentrations in soil samples may be reasoned to geochemical and biogeochemical fractionation while those in juice may be due to the changes in the environmental conditions, chemical composition and botanic structures. Variations in trace element contents in the products formed during the successive stages of sugar industry may be a result of evaporation, filtration processes, chemical treatments or corrosion of vessels, containers or engines. Trace elements are very important where they are responsible for enzymatic and biochemical reactions, matabolism, health and diseases.

Carbohydrates↗
PubMed1997

Relations of the numbers of protein sequences, families and folds.

The relations among the numbers of protein sequences, families and folds have been studied theoretically. It is found that the number of families is related to the natural logarithm of the number of sequences. The logarithmic relation should not be changed regardless of what value of the homology threshold is applied in the protein sequence comparison routines. To study the relation between the numbers of families and folds, the degenerate degree of a fold has been introduced. The degenerate degree of a fold is the number of protein families which adopt the same fold. The distribution of the degenerate degrees of folds has been found to be very likely exponential. Based on the distribution, the average degenerate degree d is calculated. The number of folds is simply equal to that of families divided by the average degenerate degree of folds. It is shown that d is an increasing function of time. The current value of d is about 2. It will continue to increase and reach the value of at least 3.3 in some years. By using the above result, the numbers of protein folds for four species have been estimated. In particular, the number of folds for human proteins is estimated to be < or =5200.

Animals↗
PubMed1999

Characterization of a vanillic acid non-oxidative decarboxylation gene cluster from Streptomyces sp. D7.

The genetics of non-oxidative decarboxylation of aromatic acids are poorly understood in both prokaryotes and eukaryotes. Although such reactions have been observed in numerous micro-organisms acting on a variety of substrates, the genes encoding enzymes responsible for these processes have not, to our knowledge, been reported in the literature. Here, the isolation of a streptomycete from soil (Streptomyces sp. D7) which efficiently converts 4-hydroxy-3-methoxybenzoic acid (vanillic acid) to 2-methoxyphenol (guaiacol) is described. Protein two-dimensional gel analysis revealed that several proteins were synthesized in response to vanillic acid. One of these was characterized by partial amino-terminal sequencing, leading to the cloning of a gene cluster from a genomic DNA lambda phage library, consisting of three ORFs, vdcB (602 bp), vdcC (1424 bp) and vdcD (239 bp). Protein sequence comparisons suggest that the product of vdcB (201 aa) is similar to phenylacrylate decarboxylase of yeast; the putative products of vdcC (475 aa) and vdcD (80 aa) are similar to hypothetical proteins of unknown function from various micro-organisms, and are found in a similar cluster in Bacillus subtilis. Northern blot analysis revealed the synthesis of a 2.5 kb mRNA transcript in vanillic-acid-induced cells, suggesting that the cluster is under the control of a single inducible promoter. Expression of the entire vdc gene cluster in Streptomyces lividans 1326 as a heterologous host resulted in that strain acquiring the ability to decarboxylate vanillic acid to guaiacol non-oxidatively. Both Streptomyces sp. strain D7 and recombinant S. lividans 1326 expressing the vdc gene cluster do not, however, decarboxylate structurally similar aromatic acids, suggesting that the system is specific for vanillic acid. This catabolic system may be useful as a component for pathway engineering research focused towards the production of valuable chemicals from forestry and agricultural by-products.

Amino Acid Sequence↗
PubMed1999

A comparative study of the unfolding of the endoglucanase Cel45 from Humicola insolens in denaturant and surfactant.

Cellulases are increasingly being used for industrial purposes, particularly in washing powders, yet little is known of the factors governing the stability of proteins in detergent solutions. We present a comparative analysis of the behavior of the cellulase Cel45 from Humicola insolens in the presence of the denaturant guanidinium chloride and the anionic detergent C12-LAS. Although Cel45 unfolds in GdmCl according to a simple two-state model under equilibrium conditions, it accumulates a transient intermediate during refolding. The four disulfide bonds do not contribute detectably to the stability of the native state. Cel45 is unfolded by very low concentrations of C12-LAS (1-4 mM). An analysis of 16 mutants of Cel45 shows a very weak correlation between unfolding rates in denaturant and detergent; mutants that have the same unfolding rate in GdmCl (within a factor of 1.5) vary 1,000-fold in their unfolding rates in C12-LAS. The data support a simple model for unfolding by detergent, in which the introduction of positive charges or removal of negative charges greatly increases detergent sensitivity, while interactions with the hydrophobic detergent tail contribute to a smaller extent. This implies that different detergent-mediated unfolding pathways exist, whose accessibilities depend on individual residues. Double-mutant cycles reveal that mutations in two proximal residues lead to repulsion and a destabilization greater than the sum of the individual mutations as measured by GdmCl denaturation, but they also reduce the affinity for LAS and therefore actually stabilize the protein relative to wild-type. Ligands that interact strongly with the denatured state may therefore alter the unfolding process.

Acid-Base Equilibrium↗
PubMed2005

Enhanced reactivity of Rhizopus oryzae lipase displayed on yeast cell surfaces in organic solvents: potential as a whole-cell biocatalyst in organic solvents.

Immobilization of enzymes on some solid supports has been used to stabilize enzymes in organic solvents. In this study, we evaluated applications of genetically immobilized Rhizopus oryzae lipase displayed on the cell surface of Saccharomyces cerevisiae in organic solvents and measured the catalytic activity of the displayed enzyme as a fusion protein with alpha-agglutinin. Compared to the activity of a commercial preparation of this lipase, the activity of the new preparation was 4.4 x 10(4)-fold higher in a hydrolysis reaction using p-nitrophenyl palmitate and 3.8 x 10(4)-fold higher in an esterification reaction with palmitic acid and n-pentanol (0.2% H2O). Increased enzyme activity may occur because the lipase displayed on the yeast cell surface is stabilized by the cell wall. We used a combination of error-prone PCR and cell surface display to increase lipase activity. Of 7,000 colonies in a library of mutated lipases, 13 formed a clear halo on plates containing 0.2% methyl palmitate. In organic solvents, the catalytic activity of 5/13 mutants was three- to sixfold higher than that of the original construct. Thus, yeast cells displaying the lipase can be used in organic solvents, and the lipase activity may be increased by a combination of protein engineering and display techniques. Thus, this immobilized lipase, which is more easily prepared and has higher activity than commercially available free and immobilized lipases, may be a practical alternative for the production of esters derived from fatty acids.

Agglutinins↗
PubMed2005

Construction and 3-D computer modeling of connector arrays with tetragonal to decagonal transition induced by pRNA of phi29 DNA-packaging motor.

The bottom-up assembly of patterned arrays is an exciting and important area in current nanotechnology. Arrays can be engineered to serve as components in chips for a virtually inexhaustible list of applications ranging from disease diagnosis to ultrahigh-density data storage. In attempting to achieve this goal, a number of methods to facilitate array design and production have been developed. Cloning and expression of the gene coding for the connector of the bacterial virus phi29 DNA-packaging motor, overproduction of the gene products, and the in vitro construction of large-scale carpet-like arrays composed of connector are described in this report. The stability of the arrays under various conditions, including varied pH, temperature and ionic strength, was tested. The addition of packaging RNA (pRNA) into the array caused a dramatic shift in array structure, and resulted in the conversion of tetragonal arrays into larger decagonal structures comprised of both protein and RNA. RNase digestion confirmed that the conformational shift was caused by pRNA, and that RNA was present in the decagons. As has been demonstrated in biomotors, conformational shift of motor components can generate force for motor motion. The conformational shift reported here can be utilized as a potential force-generating mechanism for the construction of nanomachines. Three-dimensional computer models of the constructed arrays were also produced using a variety of connector building blocks with or without the N- or C-terminal sequence, which is absent from the current published crystal structures. Both the connector array and the decagon are ideal candidates to be used as templates to build patterned suprastructures in nanotechnology.

Bacillus Phages↗
PubMed1993

Effectiveness of flushing on reducing lead and copper levels in school drinking water.

Samples from drinking water fountains in 50 schools in New Jersey were collected at specific times during a typical school day and analyzed for lead, copper, pH, alkalinity, and hardness. First-draw lead and copper levels (medians 0.010 mg/l and 0.26 mg/l, respectively) decreased significantly after 10 min of flushing in the morning (medians 0.005 mg/l lead and 0.068 mg/l copper), but levels increased significantly by lunchtime (medians 0.007 mg/l lead and 0.12 mg/l copper) after normal use of fountains in the morning by students. Corrosive water, as defined by the aggressive index, contained significantly higher levels of lead and copper (medians 0.012 mg/l and 0.605 mg/l, respectively) than noncorrosive water (medians 0.005 mg/l and 0.03 mg/l, respectively).

Child↗
PubMedDate not supplied

Modified enzymes for reactions in organic solvents.

Recent studies on biocatalysis in water-organic solvent biphasic systems have shown that many enzymes retain their catalytic activities in the presence of high concentrations of organic solvents. However, not all enzymes are organic solvent tolerant, and most have limited and selective tolerance to particular organic solvents. Protein modification or protein tailoring is an approach to alter the characteristics of enzymes, including solubility in organic solvents. Particular amino acids may play pivotal roles in the catalytic ability of the protein. Attaching soluble modifiers to the protein molecule may alter its conformation and the overall polarity of the molecule. Enzymes, in particular lipases, have been chemically modified by attachment of aldehydes, polyethylene glycols, and imidoesters. These modifications alter the hydrophobicity and conformation of the enzymes, resulting in changes in the microenvironment of the enzymes. By these modifications, newly acquired properties such as enhancement of activity and stability and changes in specificity and solubility in organic solvents are obtained. Modified lipases were found to be more active and stable in organic solvents. The optimum water activity (a(w)) for reaction was also shifted by using modified enzymes. Changes in enantioselective behavior were also observed.

Candida↗
PubMed2006

Sediment management in sustainable urban drainage system ponds.

Since removal and disposal of sustainable urban drainage system (SUDS) sediment can incur high maintenance costs, assessments of sediment volumes, quality and frequency of removal are required. Sediment depth and quality were surveyed annually from 1999-2003 in three ponds and one wetland in Dunfermline, Scotland, UK. Highest sediment accumulation occurred in Halbeath Pond, in the most developed watershed and with no surface water management train. From comparison of measured potentially toxic metal concentrations (Cd, Cr, Cu, Fe, Ni, Pb, Zn) with standards, the average sediment quality should not impair aquatic ecosystems. 72-84% of the metal flux into the SUDS was estimated to be associated with coarse sediment (> 500 microm diameter) suggesting that management of coarse sediment is particularly important at this site. The timing of sediment removal for these SUDS is expected to be determined by loss of storage volume, rather than by accumulation of contaminants. If sediment removal occurs when 25% of the SUDS storage volume has infilled, it would be required after 17 years in Halbeath Pond, but only after 98 years in Linburn Pond (which has upstream detention basins). From the quality measurements, sediment disposal should be acceptable on adjacent land within the boundaries of the SUDS studied.

Cities↗
PubMed1999

Diarrhoea following contamination of drinking water with copper.

Three cases of children with suspected copper intoxication from the drinking water are described. The children presented with protracted diarrhoea, which promptly disappeared, when they were given drinking water of low copper concentration but reappeared when given their domestic water. It is concluded that the use of copper tubing in the water pipes may under certain circumstances result in the presence of copper in the drinking water and the risk of intoxication, especially in small children.

Child, Preschool↗
PubMed1999

Work-related cancer in the Nordic countries.

This report presents 20 years' of cancer incidence data by occupational group for the Nordic populations. The study covers the 10 million people aged 25-64 years at the time of the 1970 censuses in Denmark, Finland, Norway, and Sweden, and the 1 million incident cancer cases diagnosed among these people during the subsequent 20 years. The project was undertaken as a cohort study with linkage of individual records based on the personal identification numbers used in all the Nordic countries. In the 1970 censuses, information on occupation for each economically active member of the household was provided in free text in self-administered questionnaires. The data were centrally coded and computerized in the statistical offices. Norway, Sweden, and Finland used the Nordic Classification of Occupations, while Denmark used a national coding scheme. However, all the data could be reclassified into 53 occupational groups and 1 group of economically inactive persons. Person-years at risk were accumulated from 1 January 1971 until the date of emigration, date of death or 31 December 1987 in Denmark, 1989 in Sweden, 1990 in Finland, and 1991 in Norway. The 4 countries all had nationwide registration of incident cancer cases during the entire study period. All incident cancer cases during the individual risk periods were included in the analysis. Despite minor differences between the countries, the International Classification of Diseases, 7th revision, formed the core basis for the diagnostic coding in all 4 countries. For the present study the incident cancer cases have been classified into 35 broad diagnostic groups. The observed number of cancer cases in each group of persons defined by country, gender, and occupation was compared with the expected number calculated from the age-, gender-, and period-specific person-years and the incidence rates for the national population. The result has been presented as a standardized incidence ratio (SIR), defined as the observed number of cases divided by the expected number and multiplied by 100. In the tables of this report, all the SIR values for which the upper limit of the 95% confidence interval is below 100 are printed in green and all those for which the lower limit of the confidence interval is above 100 are printed in red. For all cancers combined, the study showed a wide variation among the men, from an SIR of 79 for farmers to 159 for waiters. The occupations with the highest SIR values also included seamen and workers producing beverages and tobacco. Among the women the SIR values varied from 83 for gardeners to 129 for tobacco workers. Low SIR values were found for farmers and teachers. Outdoor workers such as fishermen and gardeners had the highest risk of lip cancer, while the lowest risk was found among indoor workers such as physicians and artistic workers. Almost all pleural cancers are associated with asbestos exposure. Accordingly, plumbers, welders, mechanics, and seamen were the occupations with the highest risk. There was also an excess risk of pleural cancer in the occupational group of technical, chemical, physical, and biological workers, including, among others, engineers and chemists potentially exposed to asbestos. The wood workers included in the present study had the highest risk of nasal cancer. Most studies of nasal cancer have shown increased risks associated with exposure to wood dust, both for those in furniture making and for those exposed exclusively to soft wood. Nickel refinery workers are also known for their high risk of nasal cancer. In the present study they were included in the occupational group of smelting workers. Lung cancer was the most frequent cancer among men in the present study. Tobacco smoking is the major risk factor for this disease, but occupational exposures also play an important role. Waiters and tobacco workers had the highest risk of lung cancer. Miners and quarry workers also had a high risk of lung cancer, which may be related to

Adult↗
PubMedDate not supplied

Liquid chromatographic determination of sennosides in Cassia angustifolia leaves.

A simple liquid chromatographic method was developed for the determination of sennosides B and A in leaves of Cassia angustifolia. These compounds were extracted from leaves with a mixture of methanol-water (70 + 30, v/v) after defatting with hexane. Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography and UV absorbance at 270 nm using a photodiode array detector. The method involves the use of an RP-18 Lichrocart reversed-phase column (5 microm, 125 x 4.0 mm id) and a binary gradient mobile-phase profile. The various other aspects of analysis, namely, peak purity, similarity, recovery, repeatability, and robustness, were validated. Average recoveries of 98.5 and 98.6%, with a coefficient of variation of 0.8 and 0.3%, were obtained by spiking sample solution with 3 different concentration solutions of standards (60, 100, and 200 microg/mL). Detection limits were 10 microg/mL for sennoside B and 35 microg/mL for sennoside A, present in the sample solution. The quantitation limits were 28 and 100 microg/mL. The analytical method was applied to a large number of senna leaf samples. The new method provides a reliable tool for rapid screening of C. angustifolia samples in large numbers, which is needed in breeding/genetic engineering and genetic mapping experiments.

Anthraquinones↗