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PubMed2004

Formation of haloacetic acids during monochloramination.

Factors that affect the formation of haloacetic acids (HAAs) during monochloramination, such as monochloramine application techniques, the initial chlorine (Cl) to ammonia-N (N) ratios, the bromide concentrations, and the wastewater quality, were studied. Aqueous humic acid solutions and undisinfected wastewater effluent samples obtained from two Hong Kong Sewage Treatment Works (STWs) were monochloraminated under various conditions. HAA formation was strongly affected by the monochloramine application techniques. The formation of trichloroacetic acid (TCAA) and total HAAs was reduced by adding preformed monochloramine. A higher initial Cl:N ratio indicated a higher chlorine demand and consequently led to higher HAA yields. Increasing the bromide concentration shifted HAAs from chlorinated species to brominated species and increased the yields of total HAAs, concurrent with decreases in the yields of dichloroacetic acid (DCAA) and TCAA but with increases in those of the other HAAs measured. Variations in the patterns of HAA formation were observed in monochloraminated wastewater effluent samples. The variations cannot be simply explained by the chlorine chemistry involving ammonia and/or bromide but are likely attributable to the combining effects of the water quality and the characteristics of the organics in the wastewater.

Acetates↗

PubMed1996

Effect of additives on the renaturation of reduced lysozyme in the presence of 4 M urea.

Reduced lysozyme was renatured by sulfhydryl-disulfide interchange reactions at pH 8.0 in the presence of 4 M urea, with or without additives at 40 degrees C. In the absence of additives, the final folding yield of reduced lysozyme was approximately 40%. In the presence of sarcosine, glycerol, ammonium sulfate, N-acetyl glucosamine and glucose, its folding yields increased in all cases. In particular, yields increased up to 90% in the presence of 4 M sarcosine. On the other hand, the melting temperatures of lysozyme with or without additives in 0.02 M citrate buffer (pH 6.0) were evaluated using differential scanning calorimetry. In the absence of additive, the melting temperature of lysozyme was 73.8 degrees C. In the presence of additives, all melting temperatures were higher than that of lysozyme in the absence of additives. Moreover, there was a good correlation on addition of additives between an increase in the folding yield of reduced lysozyme with 4 M urea and an increase in the melting temperature without 4 M urea. Therefore, we conclude that additives, which stabilize native lysozyme, are effective at increasing the folding yield of reduced lysozyme in 4 M urea.

Acetylglucosamine↗

PubMed1982

Enhancement of skin tumorigenesis by cigarette smoke condensate following beta-irradiation in rats.

The tumor-promoting ability of cigarette-smoke condensate (CSC) has been demonstrated in rat skin after beta-irradiation. Skin tumors from male albino Charles River CD rats (outbred Sprague-Dawley descended) were classified into 2 groups: carcinomas and other noncarcinoma tumors. A statistically significant increase (P less than 0.01) in tumor yield occurred after CSC treatment that began 2 months after irradiation. This finding confirmed our previously published pilot observation. Extension of the pilot experiment to obtain data on carcinoma yield and an experiment to observe the effects of CSC treatment beginning immediately after irradiation were performed. When CSC treatment began immediately after irradiation, the yield of noncarcinoma tumors was significantly reduced (P less than 0.01), whereas the carcinoma yield increased but statistically not significantly (P = 0.12). The increased yield of noncarcinoma tumors is attributed to a significant increase (P less than 0.01) of acute ulceration caused by CSC on recently irradiated skin. The increase in carcinoma yield resulted from an increase in the rate of conversion of noncarcinoma tumors to cancer. Carcinoma yield was also increased by CSC treatment beginning 2 months after irradiation, but the increase was not significant (P = 0.08). The lack of statistical significance for the carcinoma yields in both experiments may be ascribed to the insufficient number of cancers produced by the treatments. The relative ratios of cancer yields (1.7 and 2.5) did not differ greatly from the 2.2 ratio for the increase of noncarcinoma tumors. The possible relevance of the findings to human carcinogenesis is discussed.

Animals↗

PubMed2005

Ultrasound-assisted extraction of anthraquinones from roots of Morinda citrifolia.

This study investigated the use of ultrasound-assisted extraction (UAE) to improve the extraction efficiency of the classical solvent extraction techniques such as maceration and soxhlet extraction to extract anti-oxidant activity compounds, anthraquinones, from the root of Morinda citrifolia. The effects of different extraction conditions were determined, i.e., temperature of (25, 45, 60 degrees C), ultrasonic power, solvent types, and compositions of ethanol in ethanol-water mixtures. The results show that the yield increases with increasing extraction times and extraction temperatures. The percent recovery of anthraquinones using ultrasound was found to be highly dependent on the type of solvents (acetone > acetonitrile > methanol > ethanol). Furthermore, the use of ethanol-water solution as extraction solvent increased the yield of anthraquinones due to the relative polarity, the swelling effect of plant tissue matrix by water, and increased sound absorption. To achieve the same recovery as that achieved by UAE, soxhlet extraction and maceration required much longer time.

Anthraquinones↗

PubMed2005

Association of the protease inhibitor gene with production traits in Holstein dairy cattle.

Positional, comparative candidate gene analysis and previous quantitative trait loci linkage mapping results were used to search for candidate genes affecting milk production and reproduction traits in dairy cattle. The protease inhibitor (PI) gene was chosen for examination, and 5 single nucleotide polymorphisms were detected in coding regions of the gene by direct sequencing of reverse transcription-polymerase chain reaction products from a wide range of cattle tissues. A total of 6 different intragenic haplotypes were identified in North American Holstein population, and these were examined for associations with milk production traits in 24 half-sib families comprising 1007 sons utilizing a granddaughter design. One common haplotype was associated with increased milk and fat yields, increased productive life, and decreased somatic cell score. Another common haplotype was associated with decreased productive life and increased somatic cell score. One rare haplotype was associated with decreased milk, fat, and protein yields and increased milk protein percentage; another rare haplotype was associated with decreased milk yield, increased protein percentage, and decreased productive life. The observation that the PI gene is associated with analogous traits in humans demonstrates the effectiveness of the positional comparative candidate gene analysis that utilizes information about genes present in chromosomal regions with conserved synteny in other species.

Animals↗

PubMed1989

Cardiovascular responses and mammary substrate uptake in Jersey cows treated with pituitary-derived growth hormone during late lactation.

Pituitary-derived bovine growth hormone (bGH) was administered to Jersey cows during late lactation for 7 d. Milk yield increased significantly during treatment and by a maximum of 49.6% on d 7. The magnitude of the increase was similar to that of mammary plasma flow (47.8 +/- 18.3%) over the same period. By 15-21 d after treatment, both variables had returned to pretreatment values. With respect to milk composition, bGH had negligible effect on lactose and fat concentrations but there were significant decreases in protein, sodium and chloride. Arterial plasma concentrations of bGH increased substantially during treatment, but the associated rise in insulin was not statistically significant. Haematocrit decreased significantly, the lowest value being recorded 3 d after bGH treatment ceased. Mammary respiratory quotient fell progressively after the start of bGH treatment and reached the lowest recorded value 3 d after treatment ceased (62.2 +/- 7.3% of pretreatment value). Glucose and acetate uptake by the mammary gland increased significantly during treatment, increase in glucose uptake being due both to a greater arterio-venous difference and to mammary plasma flow. There was strong evidence that the acute response in increased milk yield was associated with multiple effects in terms of mammary plasma flow and metabolism, as well as haematocrit changes indicative of increased plasma volume.

Animals↗

PubMed1957

The influence of cortisone on experimental viral infection. IV. Negation of interference as the mechanism by which cortisone induces increased virus yields.

The interference with viral synthesis which is induced by large quantities of non-infective influenza B virus is inhibited or negated with small quantities of cortisone and other C-21 steroids. The specificity of this effect is attested by the inactivity of 11-alpha hydroxy epimers of highly active compounds. Maximal activity in negation of interference is associated with the presence of oxygen at the C-11 position of the steroid molecule. In view of the demonstration that negation of interference can occur, it is concluded that the phenomenon of multiplicity reactivation of non-infective virus is not primarily influenced by cortisone. Rather, it is suggested that the reactivation phenomenon is unmasked by cortisone through its inhibiting effect on the autointerference intrinsic in multiplicity infection. If it is accepted that influenza virus infections in ovo are self-limited in part by viral autointerference, present evidence is consistent with the view that negation of this autointerference is the mechanism by which cortisone induces definitively increased yields of virus.

Cortisone↗

PubMed2000

Crop improvement in the 21st century.

Crop yields increased dramatically in the 20th century as recorded on Broadbalk or in world averages. The vast majority of that increase has occurred since the last world war and has been powered by changes in the genetic potential of the crop and in the way in which it has been managed. Nevertheless, the challenge to feed a world population that is likely to rise to 8 billion is formidable, particularly since recent analyses suggest that the rate of increase in yields of several crops may have dropped over the last decade. What are the opportunities to meet this challenge and to continue to improve the yields of our crops? Improvements in agronomy are likely to be more concerned with efficiency and elegance rather than in major breakthroughs. More sophisticated crop protection chemicals designed on the basis of vastly increased screening potentials and (at last?) possibilities of rational design will be supplemented by a battery of decision support systems to aid management choices which can be precisely implemented. Genetic improvement is the area in which to-look for the major breakthroughs. The broad potential of recombinant DNA technology will provide the possibility of both molecular analyses of crop productivity and ways in which it may be possible to improve that productivity. The goal of analysis may be approached in three ways: starting at the beginning by generating complete sequences of the plant genome; starting at the end by genetic analysis of phenotypes using genetic marker technology; or, starting in the middle, by metabolic analysis. Improvements may be obtained by re-assorting what has been achieved through enhanced breeding technologies, by randomly induced change, and by generation of totally new possibilities through biochemical engineering. Examples of all approaches will be given. The onset of genomics will provide massive amounts of information, but the success will depend on using that to improve crop phenotypes. The ability to meet the challenges of the 21st century will depend on the ability to close that 'phenotype gap'.

Biotechnology↗

PubMed2001

Cosecretion of chaperones and low-molecular-size medium additives increases the yield of recombinant disulfide-bridged proteins.

Attempts were made to engineer the periplasm of Escherichia coli to an expression compartment of heterologous proteins in their native conformation. As a first approach the low-molecular-size additive L-arginine and the redox compound glutathione (GSH) were added to the culture medium. Addition of 0.4 M L-arginine and 5 mM reduced GSH increased the yield of a native tissue-type plasminogen activator variant (rPA), consisting of the kringle-2 and the protease domain, and a single-chain antibody fragment (scFv) up to 10- and 37-fold, respectively. A variety of other medium additives also had positive effects on the yield of rPA. In a second set of experiments, the effects of cosecreted ATP-independent molecular chaperones on the yields of native therapeutic proteins were investigated. At optimized conditions, cosecretion of E. coli DnaJ or murine Hsp25 increased the yield of native rPA by a factor of 170 and 125, respectively. Cosecretion of DnaJ also dramatically increased the amount of a second model protein, native proinsulin, in the periplasm. The results of this study are anticipated to initiate a series of new approaches to increase the yields of native, disulfide-bridged, recombinant proteins in the periplasm of E. coli.

Culture Media↗

PubMed2002

Urokinase could increase the yield of progenitor cells during red cell depletion in elapsed and anticoagulated cord blood.

We assessed whether the urokinase could increase the yield of progenitor cells during processing in elapsed, anticoagulated cord blood (CB) after collection, and we also determined the optimal dose of urokinase. The total nucleated cell (TNC) counts after red cell depletion in 48-hr-elapsed CB were significantly higher in samples treated with 10,000 and 50,000 IU of urokinase/mL than in untreated samples or treated with 5,000 IU of urokinase/mL. The CD34(+) cell counts were significantly higher in samples treated with 10,000 IU of urokinase/mL than in untreated samples and in samples treated with 5,000 or 50,000 IU of urokinase/mL. In 6-, 12-, and 24-hr-elapsed CB, however, there were no significant differences of TNC, CD34(+) cells, or CFU-GM counts between untreated samples and samples treated with 10,000 IU of urokinase/mL. These findings suggest that the addition of 10,000 IU of urokinase/mL before red cell depletion in 48-hr-elapsed, anticoagulated CB could increase the yield of progenitor cells. However, there are no advantages in using urokinase for processing CB prior to 24 hr after collection.

Anticoagulants↗

PubMed1984

Characterization of electric field-induced fusion in erythrocyte ghost membranes.

Fusion has been reported to occur in a variety of membrane systems in response to the application of certain electric currents to the medium (Zimmermann, U., 1982, Biochim. Biophys. Acta., 694:227-277). The application of a weak but continuous alternating current causes the membranes in suspension to become rearranged into the "pearl-chain" formation. Fusion can then be induced by one or more strong direct current pulses that cause pore formation. This results in the conversion of individual membranes in the "pearl-chain" formation to a single membrane with one or more hourglass constrictions that form lumens which connect the cytoplasmic compartments. As the diameter of the lumens increases, the overall membrane shape grows to one large sphere. To further characterize electric field-induced fusion, experiments were conducted using the erythrocyte ghost as a model membrane, and a new combination of electrical circuit and fusion chamber that is simpler and improved over previous systems. All odd-shaped ghosts (collapsed or partly collapsed spherical shapes, echinocytes, discocytes, and stomatocytes) in 30 mM phosphate buffer was first converted to spherocytes and then fused with increasing yields by increasing the number of pulses. After fusion, the lateral diffusion of a fluorescent lipid soluble label (Dil) from labeled to unlabeled membranes was observed to occur both with and without the appearance in phase-contrast optics of distinct communication (lumens) between cytoplasmic compartments of the fused membranes. Connections between cytoplasmic compartments, however, were unmistakable with the instant transfer of a fluorescent water-soluble label (fluorescein isothiocyanate-dextran) from labeled to unlabeled cytoplasmic compartments upon fusion. Although pulses still resulted in the lateral diffusion of Dil to unlabeled membranes, the presence of glycerol in the medium strongly reduced the yield of lumens observable by phase-contrast optics in fusion events. The presence of glycerol also inhibited the conversion of membranes to spherocytes, but did not inhibit the lateral diffusion of Dil from labeled to unlabeled membranes.

Cell Fusion↗

PubMed2004

Properties and biocompatibility of polypropylene graft copolymer films.

Modifying the surfaces of polymers has received a great deal of attention, because it could bring about specific surface characteristics such as antithrombogenic property. Therefore, N-vinyl pyrrolidone/sodium acrylate (NVP/Na-AAc) binary monomers were introduced onto polypropylene (PP) films by a radiation grafting method. The effect of solvent and comonomer composition on the degree of grafting was determined. Studies of the mechanical properties and water content of such graft copolymers showed that as the grafting yield increases the elongation percent decreases. However, the water content increases with increasing grafting yield. The blood compatibility of the original PP and PP-g-NVP/Na-AAc films was evaluated by determination of the extent of platelet adsorption and thrombus formation. The blood compatibility of PP-g-NVP/Na-AAc seems to be better than that of original PP.

Biocompatible Materials↗

PubMed2001

The bulk crystallization of alpha-lactose monohydrate from aqueous solution.

The bulk crystallization of alpha-lactose monohydrate from aqueous solution by primary nucleation has been studied under controlled conditions of supersaturation, temperature, and pH. The induction times to nucleation were extremely long compared with those generally observed for other materials, even at the high supersaturations used in the experiment. As a result, it was necessary to stir the supersaturated solution vigorously to induce nucleation in a reasonable but still lengthy working time. Even then, nucleation only occurred to a limited extent, following which growth ceased for 8-10 h before resuming. After this period, growth recommenced but again slowed to a low rate after another 8 h. At this stage, the yield of product was low and in most cases the particles had achieved sizes close to the maximum noted. The yields increased with further crystallization time (22-72 h total from the recommencement of growth) to give, under high initial supersaturation conditions, amounts of product close to the theoretical value. For the most part, however, the particle size did not increase with this later increase in yield, showing only significant changes after the extremely long total crystallization times. It is proposed that these extreme properties result from the formation in solution by mutarotation of the anomer alpha-lactose, which inhibits nucleation as well as its previously observed influence on growth.

Crystallization↗

PubMedDate not supplied

The application of papain, ficin and clostripain in kinetically controlled peptide synthesis in frozen aqueous solutions.

The capability of the cysteine proteases ficin, papain and clostripain to form peptide bonds in frozen aqueous solutions was investigated. Freezing the reaction mixture resulted in increased peptide yields in kinetically controlled coupling of Bz-Arg-OEt with various amino acid amides and dipeptides. Under these conditions, peptide yields increased up to 70% depending on the enzyme and the amino component used. Enzyme-catalysed peptide syntheses were carried out under optimized reaction conditions (temperature, amino component concentration and pH before freezing) using the condensation of Bz-Arg-OEt and H-Leu-NH2 as a model reaction.

Amino Acid Sequence↗

PubMed1991

Economic value of urea-treated straw fed to lactating buffaloes during the dry season in Nepal.

An experiment was conducted to study the effects of feeding urea-treated rice straw to lactating buffaloes in the Koshi Hills. Six pairs of similar buffaloes on farms were selected. All were given a conventional diet based on rice straw for four weeks, then one of each pair was given 15 to 20 kg/day of urea-treated rice straw for a period of four weeks while the control group received untreated rice straw. In the final four week period all animals were given the conventional diet. Feeding straw treated with 4% urea increased the voluntary intake of straw by 25% and increased milk yield by 1.6 litres/day compared with buffaloes fed the conventional diet containing untreated straw. Milk production remained elevated after the four-week treatment period had finished. The results show that buffalo cows fed urea-treated straw achieved better weight gain, and milk yield increased significantly (P less than 0.01) compared with the control animals. During the treatment period the net benefit was 4.0 (i.e. US$1.16) Nepalese currency rupees (NCRs) per day and the incremental rate of return was 46 per cent. Moreover, in the four weeks following the treatment period the net benefit was 10.0 NCRs (i.e. US$0.40) per day. Ensiling rice straw with 4% urea can be recommended as a safe, economical and suitable method for improving the nutritional value of rice straw on small farms in Nepal thus increasing milk production and liveweight of lactating buffaloes. The practice of feeding urea-treated straw is economic for farmers during the dry season from January to April.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed2003

Immobilization of Candida krusei cells producing phytase in alginate gel beads: an application of the preparation of myo-inositol phosphates.

Cells of Candida krusei capable of producing phytase were immobilized in Ca-alginate gel beads and used for the preparation of myo-inositol phosphates. The immobilization yield was increased about 5-fold after the beads were treated for 96 h at pH 4.0, 4 degrees C. The increased yield was retained, even after 1 month, when the cells were kept at this temperature and pH. No shift in the pH optima of phytase of the immobilized cells was observed, compared with that of free cells. However, the optimum temperature for the enzyme of the immobilized cells was 55 degrees C, which was 15 degrees C higher than that of free cells. The degradation characteristics of the phytate in immobilized cells packed in a glass column (i.d. 1.2 cm, length 20 cm) were investigated. The variation in the composition of the products results from a change in the flow rate of phytate solution (5 mM). At a flow rate of 1.30 ml/min, a mixture of myo-inositol-2-monophosphate, myo-inositol-1,2,5-triphosphate and myo-inositol-1,2,5,6-tetrakisphosphate was produced, in which the latter two were physiologically active. Also, it was found by NMR analysis that the enzyme of this strain produced only one isomer of each of the inositol phosphates, with the exception of myo-inositol pentakisphosphate. Therefore, the pure isomers were easily isolated using ion-exchange chromatography.

6-Phytase↗

PubMed2005

Catalytically increased prebiotic peptide formation: ditryptophan, dilysine, and diserine.

"Mutual" amino acid catalysis of glycine on the formation of ditryptophan, dilysine, and diserine in the prebiotically relevant Salt-Induced Peptide Formation (SIPF) Reaction was investigated varying the starting concentration and chirality of the educt amino acid, and analyzing the increase of yield resulting from this catalytic effect. Our results show the possibility of an amplified diverse pool of peptides being available for chemical evolution of larger peptides and proteins using also these more complicated amino acids for the evolution of more complex functions in future biochemical cycles and thus for the emergence of life. Catalytic effects are especially high in the case of serine, the most basic amino acid of the three, but are also significant for the other two examples investigated in the present work. Besides that, especially for serine, but also in the case of tryptophan, differences in catalytic yield increase according to the chiral form of the amino acid used could be observed.

Amino Acids↗

PubMed1992

Glycosylation inhibits the interaction of invertase with the chaperone GroEL.

During refolding and reassociation of chemically denatured non-glycosylated invertase from Saccharomyces cerevisiae, aggregation competes with correct folding, leading to low yields of reactivation (Kern et al. (1992) Protein Sci. 1, 120-131). In the presence of the chaperone GroEL, refolding is completely arrested. This suggests the formation of a stable complex between GroEL and non-native non-glycosylated invertase. Addition of MgATP results in a slow release of active invertase from the chaperone complex. When GroEL/ES and MgATP are present during refolding, the final reactivation yield increases from 14% to 36%. In contrast, refolding of the core-glycosylated and the high-mannose glycosylated forms of invertase is not arrested by GroEL. Only a short lag phase at the beginning of reactivation and a slightly increased reactivation yield (64% to 86% for core-glycosylated and 62% to 76% for external invertase) indicate a weak interaction of the glycosylated forms with the chaperone.

Bacterial Proteins↗