Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “yield”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,387 records · Page 77Linked to original sources
PubMed1993

An improvement in the pyruvate dehydrogenase complex assay: a high-yield method for purifying arylamine acetyltransferase.

A new method for purifying arylamine acetyltransferase (AAT) has been devised using polyethylene glycol fractionation and hydroxylapatite chromatography. The new procedure gives a final yield of approximately 70% based on activity in crude homogenates and can be performed in a single day. This represents a threefold higher yield than previous methods. The procedure may be used to purify AAT from pigeon, chicken, and duck livers with equivalent yield of the final enzyme. However, the preparation from pigeon liver is preferred because of the sevenfold higher activity in this tissue. Nevertheless, if fresh pigeon livers cannot be acquired, calculations reveal that the preparation from chicken liver is comparable to that from pigeon liver acetone powder with respect to total activity obtained per gram wet weight starting material. One can also calculate that the chicken liver preparation is approximately 40 times cheaper than that from pigeon liver acetone powder, making the preparation of AAT from fresh chicken livers a good alternative when pigeon livers are not available.

Aniline Compounds↗
PubMed1994

Analysis of lymphocyte proliferation data: do different approaches yield the same results?

We addressed whether different approaches to the treatment of lymphocyte proliferation data influence the interpretation of results. We focused on two specific issues: (1) the impact of using optimal concentrations of mitogen versus a repeated measures approach using all concentrations and (2) the impact of correcting for unstimulated wells, and the method chosen for doing so. First, analysis of only the optimal concentration yields the same results as using a repeated measures approach. Second, uncorrected stimulated data, difference scores, and statistical control of unstimulated values all yield identical conclusions. The stimulation index, however, frequently yields different outcomes than the other approaches. We discuss reasons for these differences, note that the equivalence between repeated measures and optimal concentration techniques is limited to studies predicting suppression of proliferation irrespective of concentration, and suggest situations when the various approaches to analysis be used.

Adult↗
PubMed1993

Lymph node yield from laparoscopic lymphadenectomy in cervical cancer: a comparative study.

Pretreatment surgical staging in cervical cancer has been studied extensively but remains controversial because a surgical procedure is required and the information gained may benefit only a small portion of the patients staged. Pelvic and paraaortic laparoscopic lymphadenectomies have been successfully performed in animal models and humans. Little information regarding the validity of the procedure in patients who have had subsequent laparotomy exists. In this series, we report our preliminary experience in 12 patients who underwent laparoscopic lymphadenectomy and then laparotomy. Overall, 377 pelvic nodes were removed, with 282 (75%) obtained at laparoscopy. The average number of pelvic nodes removed at laparoscopy was 23.5 (range 7-33). Two patients had positive pelvic nodes. No patient with negative nodes at laparoscopy had positive nodes at laparotomy. When studied in chronological order, the lymph node yield from our second 6 patients was much improved over our first 6 patients, 85% versus 63% (P < 0.005). Laparoscopy also proved to be a better predictor of lymph node spread than computed tomography. Two patients also had right-sided paraaortic lymphadenectomies, yielding 8 and 5 nodes. No additional right-sided paraaortic nodes were detected at laparotomy for either patient. In this preliminary series, laparoscopic lymphadenectomy appears to be a feasible procedure for surgical staging of cervical cancer. The yield of pelvic lymph nodes is adequate and improved with experience. Most importantly, no positive lymph nodes were missed by laparoscopy. The indications for operative laparoscopy have expanded rapidly. Gynecologic oncologists performing this procedure should be involved in prospective studies of this technique to set the standards and indications of this new technology.

Adult↗
PubMed1997

Phospholipase C isoforms delta 1 and delta 3 from human fibroblasts. High-yield expression in Escherichia coli, simple purification, and properties.

Phospholipase C isoforms delta 1 and delta 3 (PLC delta 1 and delta 3) were expressed in Escherichia coli using the cDNA sequences from human fibroblasts. The enzymes were also expressed with the sequence Met-Gly-His6-Ser-Gly-Leu-Phe-Lys-Arg, a hexahistidine sequence followed by a Kex2 protease cleavage site, denoted as "-H6K2," attached to their amino termini. PLC delta 1, PLC delta 1-H6K2, PLC delta 3, PLC delta 3-H6K2 all expressed in highly active form. The H6K2-bearing isoforms were each purified to homogeneity in a single step, with yields of 90-100%, using agarose-iminodiacetic acid-Ni columns and imidazole buffer as eluting agent. Yields in terms of activity increased as the temperature of expression was decreased. Expression at 16 degrees C for 72 h yielded 33 mg of pure PLC delta 1-H6K2 and 13 mg of pure PLC delta 3-H6K2 per liter of culture. Removal of H6K2 from both isoforms with Kex2 protease resulted in little or no loss of activity. Expression of PLC isoforms bearing -H6K2 at the amino terminus resulted in about 12 times more activity than expression of the isoforms lacking -H6K2. PLC delta 3 is much less stable than PLC delta1. Successful purification and storage of PLC delta 3 depends on a suitable stabilizing medium. Both isoforms require 0.3 microM calcium ion for half-maximum activity. The specific activities of the isoforms expressed with and without -H6K2 are the same, as are their calcium saturation curves.

Amino Acid Sequence↗
PubMed1999

Use of rifampicin in T7 RNA polymerase-driven expression of a plant enzyme: rifampicin improves yield and assembly.

Expression systems based on high selectivity and activity of T7 RNA polymerase and presence of a strong T7 promoter have been commonly used for cloning and expression of various recombinant proteins in Escherichia coli. When the expression system is designed in such a way that the produced protein is not being transferred into periplasm, bacterial cells must be lysed in order to isolate and purify the protein. The final yield and quality of the synthesized protein then depend on various factors, protein size, amino acid sequence, solubility in cytoplasm, and folding requirements among them. The yield in the T7 RNA polymerase/promoter system can be positively influenced by use of rifampicin. In this report we demonstrate usefulness of the antibiotic in detail. We describe rifampicin-enhanced expression of a plant cytokinin-specific beta-glucosidase. Two bacterial cultures are compared, one expressing the enzyme without and one in the presence of rifampicin. The antibiotic not only increased the yield of the recombinant protein, which seems to be a general phenomenon, but also favored the final assembly of the protein's subunits into a catalytically active dimer form.

Blotting, Western↗
PubMed1999

Guinea pig liver transglutaminase: A modified purification procedure affording enzyme with superior activity in greater yield.

Tissue transglutaminase purified from guinea pig livers has a very broad substrate specificity in comparison with other members of the transglutaminase family and therefore is useful for substrate analogue kinetic studies. Modifications made in our laboratory to the standard purification protocol (J. E. Folk and S. I. Chung, 1985, Methods Enzymol. 113, 358-364) have yielded a 28% increase in specific activity and 55% increase in overall yield, while reducing the number of steps to the purification. Herein we report some of the highest yields and specific activities for guinea pig liver transglutaminase found in the literature, as well as the use of lyophilization as a solution to the long-standing problem of enzyme stability during storage.

Animals↗
PubMed1984

Velocity sensitivity of yielding during stretch in the cat soleus muscle.

Yielding of muscle force occurs when a muscle is stretched by a sufficiently large amount. A higher velocity of stretch requires a larger stretch to cause yielding, and the preyield stiffness is constant. The yield is attributed to cross-bridge disengagement and the velocity sensitivity to a mechanical filtering of this event.

Animals↗
PubMed1993

A prospective study of cigarette tar yield and lung cancer.

We examined the relationship of cigarette tar yield and other cigarette-usage characteristics in current smokers to the incidence of lung cancer in a study population of 79,946 Kaiser Permanente Medical Care Program members, aged 30-89 years, who completed a detailed, self-administered, smoking-habit questionnaire during the years 1979 through 1985. Mean length of follow-up was 5.6 years. There were 302 incident lung cancers, of which 89 percent occurred in current or former smokers. The tar yield of the current cigarette brand was unassociated with lung cancer incidence (relative risk [RR] = 1.02 per 1 mg tar-yield in men, 95 percent confidence interval [CI] = 0.98-1.05; RR = 0.99, CI = 0.96-1.03 in women). However, in long-term (> 20 years) smokers, the risk of lung cancer was decreased in women who had smoked filtered cigarettes for 20 or more years relative to lifelong smokers of unfiltered cigarettes (RR = 0.36, CI = 0.18-0.75), but not in men who had smoked filtered cigarettes for 20 or more years (RR = 1.04, CI = 0.58-1.87).

Adult↗
PubMed1995

Improved yields of the extracellular domain of the epidermal growth factor receptor produced using the baculovirus expression system by medium replacement following infection.

The extracellular domain of the epidermal growth factor receptor (EGFR) was expressed using the baculovirus expression vector system. The maximum level of the EGFR extracellular domain secreted into the medium in Sf-9 (Spodoptera frugiperda or fall army-worm) cell batch culture was approximately 2.5 micrograms ml-1. In order to increase this yield, a process was developed that included the following sequence of steps: batch growth to maximum cell density, infection of the cells with recombinant virus, and replacement of spent medium. By using this process, the specific yield of recombinant protein, which in batch culture drops when infection is carried out at densities greater than 3 x 10(6) cells ml-1, can be maintained at a maximum in cultures infected at densities of 10(7) cells ml-1 or greater. The process, when applied to 3-1 and 11-1 bioreactor cultures, allowed a maximum volumetric yield of triple the maximum value attainable in batch culture. Spent-medium analysis indicates that medium replacement provides certain nutrients that could otherwise be limiting for recombinant protein production.

Amino Acids↗
PubMedDate not supplied

The contributions of cigarette yield, consumption, inhalation and puffing behaviour to the prediction of smoke exposure.

The overall predictability of smoke exposure indicators and the importance of different influencing factors were assessed in a cross-sectional study (n = 144), using multiple linear regression and bivariate correlation analyses. Respiratory CO, and plasma nicotine and cotinine concentrations were measured before and after smoking, for lip or holder smoking, and natural or standardized (30 puffs) puffing. The prediction of smoke exposure measures varied considerably across sampling times, smoking conditions, and dependent variables. The variance of plasma cotinine and nicotine were predictable to a considerable extent (30%; 19-41%) by cigarette yield, consumption and self-reported inhalation, whereas respiratory CO was less predictable (15-27%). Generally, consumption was the most important predictor, surpassed by nicotine yield for post-smoking plasma nicotine. Smoke exposure from a single smoking period could be predicted to a variable degree (CO, 11-42%; nicotine, 33-54%) by a subset of smoker's sex, cigarette yield, self-reported inhalation and puffing characteristics. The highest prediction was found under standardized smoking conditions (30 puffs through a holder), the lowest under natural smoking conditions. The best subset of predictors, especially with respect to puffing parameters, was found to vary considerably across smoking conditions and dependent variables.

Administration, Inhalation↗
PubMed1979

Growth yield and energy generation in anaerobically-grown Campylobacter spec.

An anaerobic continuous culture study was made with Campylobacter spec. to determine growth yields under various growth conditions. The growth media contained 0.1% (w/v) yeast extract as carbon source. When grown in an aspartate-limited culture Ymaxasp was 4.6. Inclusion of formate in the culture medium hardly affected the true growth yield. The number of ATP equivalents generated in the fumarate-reductase system was 0.66 and the YmaxATP was 7.0. In the nitrate reduction with formate 1.7 ATP equivalents were generated, and a YmaxNO3- of 12.2 was observed. The true growth yield obtained with a mixture of lactate and aspartate was lower than that found with aspartate alone.

Adenosine Triphosphate↗
PubMedDate not supplied

A new thermodynamically based correlation of chemotrophic biomass yields.

A new, generally applicable, thermodynamically based method is proposed to provide an estimation of the biomass yield on arbitrary organic and inorganic substrates. Aerobic, anaerobic, denitrifying growth systems with and without reversed electrontransport are covered. The biomass yield can be estimated with only 15% error in a very wide range of microbial growth systems and biomass yields (0.01-0.80 C-mol/(C)-mol). This method is based on the use of 'Gibbs energy dissipated per C-mol produced biomass' (designated as Ds01/rAx) as the central parameter. Moreover the insufficiency of other methods based on YATP, YAve, eta o, YC and enthalpy or Gibbs energy efficiencies is shortly discussed. Also it appeared to be possible to understand the obtained correlation of Ds01/rAx in general biochemical terms.

Adenosine Triphosphate↗
PubMed1982

Chemically defined medium for high yields of sterigmatocystin.

Isolate of Aspergillus versicolor strain produced 138 micrograms/ml of sterigmatocystin in a complete synthetic medium containing sucrose, salts, 1-phenylalanine, and Ca-pantothenate. The SSP (sucrose salts phenylalanine) medium apparently provided all necessary ingredients for the production of high levels of sterigmatocystin. For optimal sterigmatocystin formation, the amounts of sucrose and 1-phenylalanine were found to be 200 g and 5 g per liter, respectively. When Ca-pantothenate (0.01 g per liter) added, much higher amounts of sterigmatocystin were recovered, whereas CaCl2 addition (0.01%) drastically reduced the yield. The high levels of sterigmatocystin were recovered in the cultures which incubated stationary at 26 to 29 degrees C for over 12 days. Seven strains or isolates tested yielded high levels of sterigmatocystin in the SSP medium, whereas in each other media such as YES medium and rich medium only one isolate yielded highest amount of sterigmatocystin was found.

Aspergillus↗
PubMed1991

A theoretical evaluation of growth yields of yeasts.

Growth yields of Saccharomyces cerevisiae and Candida utilis in carbon-limited chemostat cultures were evaluated. The yields on ethanol and acetate were much lower in S. cerevisiae, in line with earlier reports that site I phosphorylation is absent in this yeast. However, during aerobic growth on glucose both organisms had the same cell yield. This can be attributed to two factors: --S. cerevisiae had a lower protein content than C. utilis; --uptake of glucose by C. utilis requires energy whereas in S. cerevisiae it occurs via facilitated diffusion. Theoretical calculations showed that, as a result of these two factors, the ATP requirement for biomass formation in C. utilis is 35% higher than in S. cerevisiae (theoretical YATP values of 20.8 and 28.1, respectively). The experimental YATP for anaerobic growth of S. cerevisiae on glucose was 16 g biomass.mol ATP-1. In vivo P/O-ratios can be calculated for aerobic growth on ethanol and acetate, provided that the gap between the theoretical and experimental ATP requirements as observed for growth on glucose is taken into account. This was done in two ways: --via the assumption that the gap is independent of the growth substrate (i.e. a fixed amount of ATP bridges the difference between the theoretical and experimental values). --alternatively, on the assumption that the difference is a fraction of the total ATP expenditure, that is dependent on the substrate. Calculations of P/O-ratios for growth of both yeasts on glucose, ethanol, and acetate made clear that only by assuming a fixed difference between theoretical and experimental ATP requirements, the P/O-ratios are more or less independent of the growth substrate. These P/O-ratios are approximately 30% lower than the calculated mechanistic values.

Acetates↗
PubMed1986

Total and poly(A) RNA yields during an aluminum encephalopathy in rabbit brains.

The yields of total and poly(A) RNA were examined in rabbit forebrains during an experimentally induced aluminum encephalopathy. Rabbits (35 day old) were injected intracranially with 13 mumole Al lactate and sacrificed 1, 3, 7, 10, or 12 days later. IRNA yields (total RNA minus transfer RNA) were not significantly altered during the encephalopathy. Poly(A) RNA yields, assayed by oligo(dT)-cellulose fractionation and by a [3H]poly(U) hybridization assay on IRNA, were increased significantly by the end of the asymptomatic stage of the encephalopathy (7 days post-Al injection). The increase in messenger RNA population may represent either a compensatory response to cell damage induced by aluminum or the accumulation of messenger RNA for proteins directly related to the expression of aluminum toxicity.

Aluminum↗
PubMed1995

Effect of fertilization treatments on yield parameters and mucilage and fat contents in roots of moghat (Glossostemon bruguiri Desf.).

Moghat plants, Glossostemon bruguieri, Desf., received three levels of both N and K fertilizers, either alone or in combination, with a basic dose of P for all the treatments. The results with one and two year old plants revealed the importance of potassium for higher yield of roots, reflected in greater length and diameter. The lower level K1 was enough to attain that goal and the N1K1 treatment was the best in this regard. On the other hand, N fertilization rather favoured the vegetative growth and seed yield. Both N and K fertilization decreased the mucilage content of the roots, but increased their fat content. The root yield after two years increased by 72% compared with one year old plants. That increment was rather dependent on the root diameter than its elongation. The mucilage content was doubled, while the fat content decreased.

Egypt↗
PubMed1986

Somatic cell count and milk yield in relation to haemoglobin concentration in Finnish dairy goats.

Using 400 Finnish goats, the relationship between haemoglobin concentration and somatic cell counts and milk yield was studied. On the basis of haemoglobin concentration the goats were divided into two groups (greater than or less than 5.6 mmol .l-1). Goats with high haemoglobin concentrations had a markedly higher milk yield and the milk had a lower somatic cell count. In contrast, goats with low haemoglobin concentration (less than 5.6 mmol . l-1) had lower milk yields but higher cell counts. The results showed a negative correlation between the cell counts and the haemoglobin concentration.

Animal Husbandry↗
PubMed2006

Morphological, yield, cytological and molecular characterization of a bread wheat x tritordeum F1 hybrid.

The morphological, yield, cytological and molecular characteristics of bread wheat x tritordeum F(1) hybrids (2n = 6x = 42; AABBDH(ch)) and their parents were analysed. Morphologically, these hybrids resembled the wheat parent. They were slightly bigger than both parents, had more spikelets per spike, and tillered more profusely. The hybrids are self-fertile but a reduction of average values of yield parameters was observed. For the cytological approach we used a double-target fluorescence in situ hybridization performed with total genomic DNA from Hordeum chilense L. and the ribosomal sequence pTa71. This technique allowed us to confirm the hybrid nature and to analyse chromosome pairing in this material. Our results showed that the expected complete homologous pairing (14 bivalents plus 14 univalents) was only observed in 9.59% of the pollen mother cells (PMCs) analysed. Some PMCs presented autosyndetic pairing of H(ch) and A, B or D chromosomes. The average number of univalents was higher in the wheat genome (6.8) than in the H(ch) genome (5.4). The maximum number of univalents per PMC was 20. We only observed wheat multivalents (one per PMC) but the frequency of trivalents (0.08) was higher than that of quadrivalents (0.058). We amplified 50 RAPD bands polymorphic between the F(1) hybrid and one of its parents, and 31 ISSR polymorphic bands. Both sets of markers proved to be reliable for DNA fingerprinting. The complementary use of morphological and yield analysis, molecular cytogenetic techniques and molecular markers allowed a more accurate evaluation and characterization of the hybrids analysed here.

Breeding↗