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PubMed1994

Physiological factors of growth and susceptibility to virus regulating Vero cells for optimum yield of vaccinia and cloned gene product (beta-hCG).

Replication of vaccinia virus carrying beta-hCG gene at the 'tk' locus was studied in microcarrier culture of Vero cell. The yields of recombinant vaccinia virus and its expressed product (beta-hCG) were influenced by the physiological state of the host cell, at which it was infected. Cells infected with the virus between the 3rd and 6th day gave maximum amount of virus and beta-hCG in a parallel manner, the yields of which were 2.3 x 10(9) pfu per 10(6) cells and 450 ng per 10(6) cells, respectively. The yields were reduced by 33-36% in the virus-infected stationary culture of the 8th day. The physiological state of the host cell has been quantified by the cellular activity parameter 'P' (mu(t)/mu max) in the scale of 1 to 0. The value of 'P' was highest in the exponentially growing culture, which reduced with decline in growth rate. The cellular energy generation has been related with the parameter 'P'. ATP generation was reduced to 55% in the stationary culture on the 8th day (P = 0). Also, the adsorption of virus was reduced by nearly 55% in extremely slow growing or stationary culture. Host cells at moderate growth rate (P > or = 0.15) were found to be optimum for maximizing the yield of viral products.

Adenosine Triphosphate↗
PubMed1988

Modeling the impact of ozone x drought interactions on regional crop yields.

The influence of soil moisture stress on crop sensitivity to O3 was evaluated for corn (Zea mays L.), cotton (Gossypium hirsutum L.), soybean (Glycine max L. Merr.), and wheat (Triticum aestivum L.) grown in the United States. This assessment was accomplished by using yield forecasting models to estimate the influence of soil moisture deficits on regional yield and a previously developed model to predict moisture stress x O3 interactions. Reduced crop sensitivity to O3 was predicted for those regions and years for which soil moisture stress reduced yield. The models predicted a drought-induced reduction in crop sensitivity to O3 of approximately 20% for the 1979 to 1983 period; i.e. a hypothetical O3-induced yield reduction of 5% for adequately watered crops would have been reduced to a 4% effect by the 1979 to 1983 distribution of soil moisture deficits. However, predicted drought effects varied between crops, regions, and years. Uncertainties in the model predictions are also discussed.

Journal Article↗
PubMed1990

Yield loss assessments for cultivars of broccoli, lettuce, and onion exposed to ozone.

The effects of the photochemical oxidant air pollutant ozone (O(3)) on growth and yield of three garden crops, broccoli (Brassica oleracea L.), lettuce (Lactuca sativa L.), and onion (Allium cepa L.) were studied in an open-top chamber experiment conducted in the field in southern California. Four cultivars each of leaf lettuce, broccoli, and globe onion were exposed to charcoal-filtered air (CF), non-filtered (NF) air, or NF plus 1.5 times ambient O(3) concentration from 4 weeks after germination in January or February until harvest. Exposures lasted 31 days for lettuce, 55 to 78 days for broccoli, and 105 days for onion. Results showed that despite severe O(3) injury to outer leaves, lettuce yields were not affected by O(3). Broccoli also was resistant to O(3) and no growth reduction was observed at ambient O(3) concentrations. Onions were more susceptible to O(3), but only one cv. 'Rio Bravo' had significant yield losses (ca. 5%) at ambient O(3) levels. These results suggest that, in general, concentrations of O(3) in the winter and spring may be below the threshold for adverse effects on yields of broccoli, lettuce and onion.

Journal Article↗
PubMed1990

Modeling the effects of ozone on soybean growth and yield.

A simple mechanistic model was developed based on an existing growth model in order to address the mechanisms of the effects of ozone on growth and yield of soybean [Glycine max. (L.) Merr. 'Davis'] and interacting effects of other environmental stresses. The model simulates daily growth of soybean plants using environmental data including shortwave radiation, temperature, precipitation, irrigation and ozone concentration. Leaf growth, dry matter accumulation, water budget, nitrogen input and seed growth linked to senescence and abscission of leaves are described in the model. The effects of ozone are modeled as reduced photosynthate production and accelerated senescence. The model was applied to the open-top chamber experiments in which soybean plants were exposed to ozone under two levels of soil moisture regimes. After calibrating the model to the growth data and seed yield, goodness-of-fit of the model was tested. The model fitted well for top dry weight in the vegetative growth phase and also at maturity. The effect of ozone on seen yield was also described satisfactorily by the model. The simulation showed apparent interaction between the effect of ozone and soil moisture stress on the seed yield. The model revealed that further work is needed concerning the effect of ozone on the senescence process and the consequences of alteration of canopy microclimate by the open-top chambers.

Journal Article↗
PubMed1993

Model analysis of interactive effects of ozone and water stress on the yield of soybean.

The interactive effects of ozone and water stress on the yield of soybean (Glycine max (L.) Merr. 'Davis') were addressed with a growth model of soybean. Two simulations were conducted, using the data from the exposures of soybean to ozone in open-top chambers under two soil moisture regimes, and the results of the simulations were compared. In the original simulation, soil moisture content was calculated based on a water budget using the actual precipitation and irrigation data. In the modified simulation, the soil water content was given as input data. In this case, soil moisture content was maintained at the same level across the ozone treatments regardless of different water use by the plants. Both simulations included the effect of reduced ozone flux to the leaves due to water stress, whereas only the original simulation included the effect of mitigated water stress due to reduced water use by the plants under higher ozone concentration. The water stress reduced ozone impact on soybean yield in the original simulation on the basis of the ozone dosecrop yield response relationship, but not in the modified simulation. The ozone uptake rate was reduced by water stress in the original simulation, but the relationship between seasonal mean ozone uptake rate and relative yield still showed reduced impact of ozone due to water stress. These results indicated that the alleviation of water stress by ozone due to reduced plant water use in ozone-treated plots can be a contributing factor in the reduction of ozone impact by water stress. The above conclusion was partly confirmed by the actual data for soil water content, which was significantly lower in the lowest ozone treatment than in the higher ozone treatments. Further experimental and modelling studies are needed to elucidate the mechanism of the ozone X water stress interaction.

Journal Article↗
PubMed1994

Growth and yield responses of spring wheat (Triticum aestivum L. CV. Turbo) grown in open-top chambers to ozone and water stress.

Spring wheat (Triticum aestivum L.) cv. Turbo was exposed to different levels of ozone and water supply in open-top chambers in 1991. The plants were grown either in charcoal filtered air (CF), not filtered air (NF), in charcoal filtered air with proportional addition of ambient ozone (CF1), or in charcoal filtered air with twice proportional addition of ambient ozone (CF2). The mean seasonal ozone concentrations (24 h mean) were 2.3, 20.6, 17.3, and 24.5 nl litre(-1) for CF, NF, CF1, and CF2 treatments, respectively. Ozone enhanced senescence and reduced growth and yield of the wheat plants. At final harvest, dry weight reductions were mainly due to reductions in ear weight. Grain yield loss by ozone mainly resulted from depressions of 1000 grain weight, whereas numbers of ears per plant and of grains per ear remained unchanged. Pollutants other than ozone did not alter the response to ozone, as was obvious from comparisons between CF1 and NF responses. Water stress alone did not enhance senescence, but also reduced growth and yield. However, yield loss mainly resulted from reductions in the number of ears per plant; 1000 grain weight was not influenced by water stress. No water supply by ozone treatment interactions were detected for any of the estimated parameters.

Journal Article↗
PubMed1994

Growth-stage dependent crop yield response to ozone exposure.

Data from four crop yield-loss field trials were examined to determine if analysis using an imposed phenological weighting function based on seasonal growth stage would provide a more accurate indication of impact of ozone exposure. Alfalfa (Medicago sativa L. cv. Moapa 69), dry bean (Phaseolus vulgaris L. cv. California Dark Red kidney), fresh market and processing tomato (Lycopersicon esculentum Mill. cv. 6718 VF and VF-145-B7879, respectively) were grown at 9-11 ambient field plots within southern California comprising an ambient gradient of ozone. The growing season for each crop was artificially divided into 'quarters' composed of equal numbers of whole days and roughly corresponding to specific growth stages. Ozone exposure was calculated for each of these 'quarters' and regressed against final crop yield using 163 different exposure statistics. Weighting functions were developed using reciprocal residual mean square (1/RMS) or percentage of the best 100 exposure statistics of the 163 tested (TOP100) for each of the quarters. The third quarter of the alfalfa season was clearly most responsive to ozone as measured by both of the weighting functions. Third quarter ozone was also weighted highest by both weighting functions for dry bean. Fresh market and processing tomato were each influenced the greatest by second quartero zone as demonstrated by both weighting functions. The occurrence of ozone during physiologically important events (flowering and initial fruit set in second quarter for tomato; pod development in third quarter for dry bean) appeared to influence the yield of these crops the greatest. Growth-stage-dependent phenological weighting of pollutant exposure may result in more effective predictions of levels of ozone exposure resulting in yield reductions.

Journal Article↗
PubMed1995

Effects of air pollution on rice yield in the Pakistan Punjab.

A study using open-top chambers ventilated with ambient or charcoal filtered air in the vicinity of Lahore, Pakistan demonstrated reductions of 42% and 37% in the grain yield of two cultivars of rice (Oryza sativa L.). This yield reduction was primarily due to the reduction in mean panicle number per plant, although significant effects of filtration on 1000 grain weight and the number of filled grains per panicle were also detected. The 6-h daily mean O(3) concentrations were only 10-20 nl litre(-1) during the monsoon season, but increased to 30-55 nl litre(-1) later in the growing season, while the mean NO(2) concentration during the experiment was 12 nl litre(-1). On the basis of experience in North America and Japan, the reductions in yield in the present study are substantially greater than might be predicted. The reasons for this discrepancy are discussed, together with the implications for effects on rice yield in other regions of south and south-east Asia.

Journal Article↗
PubMed1986

Milk yield and composition in mice: effects of litter size and lactation number.

Milk yield was measured by a tritiated water dilution procedure during consecutive lactations in mice suckling four, 10 or 18 young. Analysis of variance revealed positive effects of lactation number and litter size on milk yield. There was a significant correlation between maternal body weight and parity; increased body weight accounted for some, but not all, of the parity-related increases in milk yield. Peak milk yield was reached between days 10 and 16 of lactation, but the efficiency with which the growing young utilized milk for weight gain was greatest before day 7. Milk composition varied significantly during the course of lactation.

Animals↗
PubMed1993

Changes in mammary glucose and protein uptake in relation to milk synthesis during lactation in high- and low-yielding goats.

1. Glucose and protein uptake were measured in both mammary glands of two low- and two high-yielding dairy goats during lactation. 2. Low-yielding goats tended to have higher arterial glucose concentrations, but approximately 40% lower arterio-venous differences (AV) and extraction rates (E) for glucose than high-yielding goats. 3. AV and E for glucose (but not protein) were linearly related to yields of both lactose, milk protein and fat. 4. Mammary uptake of glucose is determined primarily by mammary glucose metabolism, not glucose supply; lower intracellular glucose concentration in mammary cells of genetically superior animals thus explains the more efficient mammary uptake.

Animals↗
PubMed1989

Response to selection for milk yield and metabolic challenges in primiparous dairy cows.

The effect of selection for milk yield on lactation yield, net energy balance, and on plasma growth hormone, insulin, prolactin, nonesterified fatty acids and glucose was studied in two groups of primiparous Holstein cows of differing genetic merit. Net energy balance was calculated and serial blood samples were collected for a 7 hr period at 0, 45, 90 and 180 days postpartum. Growth hormone releasing factor (.2 microgram/kg BW) was administered after 2.5 hr at 0, 45 and 180 days postpartum, while epinephrine (.7 microgram/kg BW) was administered at 90 days postpartum. Milk yield was greater, net energy balance was decreased and plasma growth hormone was greater in genetically superior selection group cows compared to control cows. Growth hormone showed similar increases in both genetic groups in response to growth hormone releasing factor, while prolactin, insulin and glucose were not altered. Epinephrine stimulated an increase in plasma nonesterified fatty acids, glucose and insulin, but responses did not differ between genetic groups. Results indicate differences exist in production efficiency, net energy balance and plasma growth hormone concentration among dairy cattle as a result of selection for milk yield and suggest that selection pressure may act to alter homeorhetic control of nutrient metabolism.

Animals↗
PubMed1986

NCA 16 alpha-[18F]fluoroestradiol-17 beta: the effect of reaction vessel on fluorine-18 resolubilization, product yield, and effective specific activity.

Although the reported synthesis of the title compound resulted in a high radiochemical yield (43% based on resolubilized 18F), the effective specific activity at EOS was low (166 Ci/mmol). Reduction in the amount of carrier fluoride in the target water improved the effective specific activity of the product, but with a concommitant decrease in the resolubilized yield of the fluoroestradiol (12.7%). A re-examination of the labeling parameters was performed to determine the conditions that would increase the yield of the fluoroestrogen and maintain a high effective activity for the product. Since the amount of resolubilized 18F in THF is important in obtaining high specific activity compounds in this type of synthesis, several types of vessels were investigated to determine their effect on the evaporation of the [18O]H2O target water and subsequent resolubilization of 18F into THF. Of the vessels (Pt crucible, borosilicate glass, siliconized borosilicate glass, Vacutainer), the Vacutainer afforded the highest resolubilization of 18F into THF (90%), resulting in an improved resolubilized yield for the fluoroestradiol (28%) and an increased effective specific activity at EOS for the product (1600-3939 Ci/mmol).

Estradiol↗
PubMed1992

N-(m-[125I]iodophenyl)maleimide: an agent for high yield radiolabeling of antibodies.

In an effort to radiolabel antibodies, N-(m-[125I]iodophenyl)maleimide (m-[125I]IPM) was prepared by the demetallation of an N-[m-tri-(n-butyl)stannylphenyl]maleimide intermediate. The unlabeled intermediate was synthesized in greater than or equal to 75% yield using a palladium catalyzed reaction of hexabutylditin with m-bromoaniline, followed by reaction with maleic anhydride and ring annulation. All products were confirmed by NMR and elemental analysis. Labeling with 125I was carried out in a biphasic mixture containing chloramine-T (radiochemical yield greater than or equal to 70%). Rabbit IgG modified with the heterobifunctional crosslinking agent N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) and bovine serum albumin were conjugated with m-[125I]IPM (yield: 40 and 80%, respectively). In addition, m-[125I]IPM was conjugated to rabbit IgG subunits (HL) in 70% yield. The in vitro stability of the radiolabeled proteins in serum showed less than 1% deiodination over 24 h.

Animals↗
PubMed1994

On the pH-dependent yield of hydroxyl radical products from peroxynitrite.

Nitric oxide reacts rapidly with superoxide to give the strongly oxidizing peroxynitrite anion (ONOO-), which undergoes spontaneous first-order decomposition when protonated. The oxidative chemistry of peroxynitrite (ONOO-) is highly pH-dependent. At acidic pH, peroxynitrous acid (ONOOH) oxidizes dimethylsulfoxide to formaldehyde and 2,2'-azino-bis-(3-ethyl-1,2- dihydrobenzothiazoline 6-sulfonate) (ABTS) to the greenish-colored ABTS+ radical cation. The product yield from dimethylsulfoxide and ABTS decreased at more alkaline pH with apparent pK(a)s of 7.9 and 8.2, respectively. Decreasing yield with increasing pH could not be explained by the oxidation of either formaldehyde or ABTS+ by peroxynitrite. In the presence of 50 mM dimethylsulfoxide, nitrogen dioxide was formed in approximately equimolar amounts to the other reaction product, formaldehyde. The yield of nitrogen dioxide also decreased with an apparent pK(a) of 8.0. We propose that the complex oxidative chemistry of peroxynitrite is controlled by the pH-dependent isomerization of the relatively stable cis-configuration (predominant at high pH) to the trans-configuration. Trans-peroxynitrous acid can form a vibrationally excited intermediate capable of reacting like hydroxyl radical. The vibrationally excited intermediate can also directly rearrange to nitric acid, reducing the apparent hydroxyl radical yield to less than 30%. The loss of hydroxyl radical-like reactivity can be explained on the basis of ionization of trans-peroxynitrous acid to the trans-anion, which in turn undergoes internal rearrangement to nitrate without forming a strong oxidant.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzothiazoles↗
PubMed2005

Crop yield and light/energy efficiency in a closed ecological system: Laboratory Biosphere experiments with wheat and sweet potato.

Two crop growth experiments in the soil-based closed ecological facility, Laboratory Biosphere, were conducted from 2003 to 2004 with candidate space life support crops. Apogee wheat (Utah State University variety) was grown, planted at two densities, 400 and 800 seeds m-2. The lighting regime for the wheat crop was 16 h of light-8 h dark at a total light intensity of around 840 micromoles m-2 s-1 and 48.4 mol m-2 d-1 over 84 days. Average biomass was 1395 g m-2, 16.0 g m-2 d-1 and average seed production was 689 g m-2 and 7.9 g m-2 d-1. The less densely planted side was more productive than the denser planting, with 1634 g m-2 and 18.8 g m-2 d-1 of biomass vs. 1156 g m-2 and 13.3 g m-2 d-1; and a seed harvest of 812.3 g m-2 and 9.3 g m-2 d-1 vs. 566.5 g m-2 and 6.5 g m-2 d-1. Harvest index was 0.49 for the wheat crop. The experiment with sweet potato used TU-82-155 a compact variety developed at Tuskegee University. Light during the sweet potato experiment, on a 18 h on/6 h dark cycle, totaled 5568 total moles of light per square meter in 126 days for the sweet potatoes, or an average of 44.2 mol m-2 d-1. Temperature regime was 28 +/- 3 degrees C day/22 +/- 4 degrees C night. Sweet potato tuber yield was 39.7 kg wet weight, or an average of 7.4 kg m-2, and 7.7 kg dry weight of tubers since dry weight was about 18.6% wet weight. Average per day production was 58.7 g m-2 d-1 wet weight and 11.3 g m-2 d-1. For the wheat, average light efficiency was 0.34 g biomass per mole, and 0.17 g seed per mole. The best area of wheat had an efficiency of light utilization of 0.51 g biomass per mole and 0.22 g seed per mole. For the sweet potato crop, light efficiency per tuber wet weight was 1.33 g mol-1 and 0.34 g dry weight of tuber per mole of light. The best area of tuber production had 1.77 g mol-1 wet weight and 0.34 g mol-1 of light dry weight. The Laboratory Biosphere experiment's light efficiency was somewhat higher than the USU field results but somewhat below greenhouse trials at comparable light levels, and the best portion of the crop at 0.22 g mol-1 was in-between those values. Sweet potato production was overall close to 50% higher than trials using hydroponic methods with TU-82-155 at NASA JSC. Compared to projected yields for the Mars on Earth life support system, these wheat yields were about 15% higher, and the sweet potato yields averaged over 80% higher.

Biomass↗
PubMed2005

On the sub-maximal yield and photo-electric stimulation of chlorophyll a fluorescence in single turnover excitations in plant cells.

A set of expressions is derived which quantifies the chlorophyll fluorescence yield in terms of rate constants of primary light reactions of PSII, the fraction of open and semi-open RCs and of the electric field sensed by the RC in the thylakoid membrane. The decay kinetics of the chlorophyll fluorescence yield after a single turnover excitation in the presence of DCMU show at least two components, one reversible within approx. 1 s and one with a dark reversion lasting more than 30 s. The latter is attributed to photochemical quenching; the fast component is interpreted to be associated at least partially with photo-electrochemical control. It will be illustrated that (i) the sub-maximal fluorescence yield in single turnover excitation is associated with semi-closure of RCs, (ii) the trapping efficiency of semi-closed centers is less than 50% of that of open centers and (iii) the fluorescence yield of antennas with semi-closed RCs has the highest sensitivity to changes in strength of photo-electric fields.

Chenopodium album↗
PubMed2004

Effects of vermicomposts produced from food waste on the growth and yields of greenhouse peppers.

Vermicomposts, produced commercially from food wastes, were substituted at a range of different concentrations into a soil-less commercial bedding plant container medium, Metro-Mix 360 (MM360), to evaluate their effects on the growth and yields of peppers in the greenhouse. Six-week-old peppers (Capsicum annum L. var. California) were transplanted into 100%, 80%, 60%, 40%, 20% or 10% MM360 substituted with 0%, 10%, 20%, 40%, 60%, 80% and 100% vermicompost. All plants were watered three times weekly with 200 ppm Peter's Nutrient Solution from the time of transplanting up to 107 days. Peppers grown in potting mixtures containing 40% food waste vermicomposts and 60% MM360 yielded 45% more fruit weights and had 17% greater mean number of fruits than those grown in MM360 only. The mean heights, numbers of buds and numbers of flowers of peppers grown in potting mixtures containing 10-80% vermicompost although greater did not differ significantly from those of peppers grown in MM360. There were no positive correlations between the increases in pepper yields, and the amounts of mineral-N and microbial biomass-N in the potting mixtures, or the concentrations of nitrogen in the shoot tissues of peppers. Factors such as: an improvement of the physical structure of the potting medium, increases in populations of beneficial microorganisms and the potential availability of plant growth-influencing-substances produced by microorganisms in vermicomposts, could have contributed to the increased pepper yields obtained.

Analysis of Variance↗
PubMed2005

Evaluation of sewage sludge, septic waste and sludge compost applications to corn and forage: yields and N, P and K content of crops and soils.

This paper presents the data from two years of experiments concerned with the application of aerobically-digested sewage sludge, anaerobic lagoon septic sludge, sewage sludge compost or fertilizer to soils for grass forage and feed corn (Zea mays L.) production at two different sites 45 km from Truro, Nova Scotia. Crop yields, plant tissue and Mehlich-1 extractable soil nutrients were evaluated; 15 elements were analyzed in the plant tissue and nine elements in the soil extracts. This paper describes the results of crop yields, plant N, P and K content and Mehlich-1 extractable P and K. The research demonstrated the fertilizer produced higher yields of grass forage than the sludge and the compost but equivalent to the sludge in corn yields. Forage and corn N, P and K contents, however, varied with treatment, crop and year, while the compost-amended soils were highest in extractable nutrients. Both sludges and the compost, therefore, could be effective sources of N, P and K for crop production. Compared to the conventional fertilizer, the nutrient availability from the organic amendments (especially N and P) was considerably lower than the 50% assumed at the start of the experiment; the sludges however, provided higher nutrient availability than the compost.

Animal Feed↗