Dry Mass Research Papers - Academia.edu (original) (raw)

Para evaluar la eficiencia de concentración de las proteínas del suero con una planta móvil compuesta por un módulo de ultrafiltración y otro de nanofiltración, se determinó la composición en sólidos totales, proteína, ceniza y lactosa del suero inicial, del concentrado proteico y de los permeados de ultra y nano filtración. El contenido en cenizas se determinó por el método oficial de la AOAC, sólidos totales por Mojonier, lactosa por colorimetría con ácido pícrico y proteína por Microkjeldahl. Los porcentajes de remoción de los compuestos en los permeados se calcularon en base a los balances de materia seca obtenidos cuando el 95% del volumen del suero original había sido removido como permeado. Se encontró que los permeados de la ultrafiltración y la nanofiltración contenían 7,31% y 5,47% de sólidos totales, de los cuales el 71,13% y el 70,46% respectivamente, fue lactosa. La eficiencia de concentración de la proteína del suero con la planta móvil de ultra y nanofiltración tangencial se hizo evidente al obtenerse un concentrado proteico que alcanzó un contenido en sólidos totales de 20,29%, de los cuales 29,17 era lactosa y 51,84% era proteína.

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- Ultra Filtration, Dry Mass, Whey protein concentrate

The effects of fire recurrence on soils were studied on calcareous sites of Mediterranean Pinus halepensis-dominated communities in Catalonia (NE Iberian Peninsula). Soil organic horizons and mineral soils of 15 sites consisting in two adjacent areas, one burnt only once (in 1994) and the other burnt twice (in the same 1994 fire but also once before, from 1975 to 1993) were surveyed 9 years after the last fire. Fire recurrence decreased the occurrence and dry mass of soil organic horizons. Total nitrogen concentration in L organic horizon was higher in less recurrently burnt areas. No other significant difference between once-and twice-burnt areas was found for any studied chemical parameter either in organic L and FH horizons or in mineral soils. The present study underlines the fact that fire effects on soil organic horizons are accumulated through consecutive fires.

The present study investigated the dynamics of nutrient utilization and various growth and physiological parameters during in vitro proliferation of apple root stock 'M9 EMLA' in two different bioreactor systems, i.e. temporary and continuous immersions. Individual shoots obtained from temporary immersion system had higher dry mass and were of better quality than those obtained from continuous immersion. In continuous immersion bioreactor, apple shoots appeared to utilize more nutrients from liquid culture medium than that from temporary immersion. The shoot growth was limited by the availability of phosphate and nitrogen in continuous immersion system. The shoots produced in temporary immersion bioreactor showed higher photosynthetic rate, maximum quantum yield of photosystem-II and slow but steady rate of nutrient absorption, indicating the occurrence of higher photomixotrophic metabolism. The study also showed that high level of antioxidant scavenging enzymes in shoots grown in continuous immersion system induced physiological changes to foster adaptation to stresses.

- by Kee Paek
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- Plant Biology, Plant growth, Nitrogen, Plant Growth Regulation

Background and Aims This paper aims at studying the capacity of an individual-based morphogenetic crop model of sugar beet growth -GreenLab -to predict the effects of population density on growth and yield. • Methods A field experiment was carried out for three homogeneous population densities to measure detailed plant development and growth of one cultivar. A set of in situ measurements were used to observe some model inputs (organs' expansion times and life-spans) and destructive data of dry masses were collected for model calibration. • Keys Results and Conclusions For all density conditions, the plasticity of total biomass production and allocation patterns was accurately simulated using the sets of optimized parameters. Most of them reveal stable across different spacing, and a few parameters vary with density: specific blade mass, time of phyllochron increase, petiole sink and the characteristic surface used to compute Beer's law at individual level. These results are a first step towards developing a predictive capacity regarding crop spacing.

Purely observational studies have documented differences in the abundance and diversity of several litterdwelling arthropods between sites adjacent to, and far from, CWD, which suggests that reduction of fallen coarse woody debris (CWD) in temperate forests by traditional forestry practices may affect the litter arthropod community. As few field experiments have directly tested the impact of CWD on arthropods inhabiting the litter at different distances from CWD, we removed CWD from replicated open plots on the floor of a second-growth deciduous forest in order to reveal the causal connection between CWD and litter-dwelling spiders, often the most diverse and abundant predators among the litter macrofauna of temperate forests. We also documented the impact of the CWD manipulation on spider prey and several other major macroarthropod groups. Before removing CWD (∅ = 14.3 ± 0.7 cm), we measured response variables as a function of distance (0.5-1.5 m) from CWD in both removal and control plots. In agreement with results of previous research that solely utilized this observational approach in temperate forests, volume and dry mass of litter, spider diversity, overall spider density, and densities of 8 of 16 major spider genera were higher adjacent to CWD before experimental manipulations. Removing CWD reduced the amount of litter and the density of spiders in litter close to where the CWD had been. Removing CWD also altered spider community structure, which had differed between litter sites adjacent to, and far from, CWD prior to the experimental removal of CWD. The patterns, though, were not completely congruent, as some of the taxa affected by the manipulation had not differed between sites prior to the removal of CWD, and vice-versa. Our findings suggest that complex interactions among structural, biotic and microclimatic factors underlie the observed responses to CWD removal by spiders and other arthropods in the litter layer. We also conclude that drawing inferences solely from observational studies is not a reliable approach for predicting the impact of changes in the amount of CWD on arthropods of forestfloor leaf litter. Further field experiments manipulating different volumes of CWD are needed in order to determine the minimum amount of CWD that should be kept on the forest floor of managed forests in order to maintain densities and diversities of major leaf-litter arthropods.

- by David Wise
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- Forestry, Forest Ecology And Management, Biodiversity, Forest Ecology

A method based on high-performance thin-layer chromatography with UV detection, is described for the rapid determination of the mycotoxin lolitrem B in perennial ryegrass infected with the endophytic fungus Acremonium lolii. The method, which requires a clean-up of the crude extract on C Sep-Pak prior to chromatographic analysis, has been validated 18 according to the criteria established by the Journal of Chromatography B. Its preliminary application to samples of seven perennial ryegrass cultivars infected with A. lolii and cultivated in France, revealed the presence of lolitrem B at concentrations ranging between 0.1 and 0.94 mg / g dry mass. These results are of epidemiological importance for studying the ''ryegrass staggers'', a neurotoxic syndrome which is induced in herbivorous animal species mainly by lolitrem B.

- by Enrique Cerdá Olmedo
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- Biotechnology, Oxidative Stress, Carotenoids, Multidisciplinary

RESUMO -Objetivou-se avaliar o efeito dos períodos de diferimento e de pastejo sobre a densidade populacional de perfilhos, a massa dos componentes morfológicos da forragem e o índice de tombamento em pastagens de Brachiaria decumbens cv. Basilisk. Dois ensaios foram conduzidos: o primeiro denominado ano 1 e, o segundo, ano 2. Adotou-se o esquema de parcelas subdivididas, segundo o delineamento em blocos casualizados, com duas repetições para cada combinação dos períodos de diferimento da pastagem com os períodos de pastejo. No ano 1, os períodos de diferimento foram 103, 121, 146 e 163 dias; e no ano 2, foram 73, 103, 131 e 163 dias. Os períodos de pastejo foram 1, 29, 57 e 85 dias. O aumento do período de diferimento elevou a densidade populacional de perfilhos reprodutivos (ano 2: de 37 para 304 perfilhos/m 2 ) e reduziu a de perfilhos vegetativos (ano 1: de 1.253 para 889 perfilhos/m 2 ; ano 2: de 1.235 para 627 perfilhos/m 2 ). Durante o período de pastejo, ocorreu diminuição no número de perfilhos vegetativo (ano 1: de 988 para 868 perfilhos/m 2 ) e reprodutivo (ano 1: de 216 para 0 perfilhos/m 2 ; ano 2: de 203 para 0 perfilhos/m 2 ) e aumento no número de perfilhos mortos (ano 1: 463 para 1.088 perfilhos/m 2 ; ano 2: de 341 para 1.010 perfilhos/m 2 ). Pastagens sob maiores períodos de diferimento e de pastejo apresentaram maior massa de colmo morto (6.093 e 3.819 kg/ha de MS nos anos 1 e 2, respectivamente) e menor massa de lâmina foliar verde (341 e 177 kg/ha de MS nos anos 1 e 2, respectivamente). Pastos de Brachiaria decumbens cv. Basilisk, submetidos a longos períodos de diferimento e de pastejo possuem características estruturais desfavoráveis à produção animal. Palavras-chave: composição morfológica, estrutura do pasto, número de perfilhos, período de diferimento, período de pastejo Structural characteristics and falling index of Brachiaria decumbens cv. Basilisk on deferred pastures ABSTRACT -This worked aimed to evaluate the effects of deferring and grazing periods on the tiller population density, morphological component mass of forage and falling index on Brachiaria decumbens cv. Basilisk pastures. Two assays were carried out: first year and second year. Subdivided plots were used according to a randomized block design with two replicates. The treatments were composed of combinations of deferred periods and grazing periods. In the first year, 103, 121, 146 and 163-day deferring periods were used; and 73, 103, 131 and 163-day deferring periods in the second year. The grazing periods were 1, 29, 57 and 85 days. The increase in the deferring period increased the population density of reproductive tillers (from 37 to 304 tillers/m 2 in the second year) and reduced the density of vegetative tillers (from 1,253 to 889 tillers/m 2 in the first year; from 1,235 to 627 tillers/m 2 in the second year). Throughout the grazing period, decrease in the vegetative (from 988 to 868 tillers/m 2 in the first year) and reproductive tillers (from 216 to 0 tillers/m 2 in the first year; from 203 to 0 tillers/m 2 in the second year) occurred, as well as increase in dead tillers (from 463 to 1,088 tillers/m 2 in the first year and from 341 to 1,010 tillers/m 2 in the second year). Pastures subjected to longer deferring and grazing periods showed higher dead stem mass (6093 and 3819 kg/ha of dry mass in the first and second years, respectively) and lower green foliar blade mass (341 and 177 kg/ha of dry mass in the first and second years, respectively). Brachiaria decumbens cv. Basilisk pastures submitted to long deferring and grazing periods have unfavorable structural characteristics to animal production.

- by José Ivo Ribeiro Júnior
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- Animal Production, Population Density, Second Year, First Year

... Marcel Babin1 and Dariusz Stramski Marine Physical Laboratory, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0238 ... Source Clay Minerals Repository, University of Missouri... more

- by Dariusz Stramski
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- Earth Sciences, Near Infrared, Biological Sciences, Environmental Sciences

Moringa oleifera seeds, an environmental friendly and natural coagulant are reported for the pretreatment of palm oil mill effluent (POME). In coagulation-flocculation process, the M. oleifera seeds after oil extraction (MOAE) are an effective coagulant with the removal of 95% suspended solids and 52.2% reduction in the chemical oxygen demand (COD). The combination of MOAE with flocculant (NALCO 7751), the suspended solids removal increased to 99.3% and COD reduction was 52.5%. The coagulation-flocculation process at the temperature of 30 • C resulted in better suspended solids removal and COD reduction compared to the temperature of 40, 55 and 70 • C. The MOAE combined with flocculant (NALCO 7751) reduced the sludge volume index (SVI) to 210 mL/g with higher recovery of dry mass of sludge (87.25%) and water (50.3%).

- by Zalina Othman
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- Engineering, Water Purification, Flocculation, Hazardous Materials

Sediment cores, representing a range of watershed characteristics and anthropogenic impacts, were collected in 11 subalpine marshes in the Lake Tahoe basin, USA and vicinity in order to trace the effect of anthropogenic impacts on sedimentation and sediment accumulation rates. Cores were 210 Pb-dated using a CRS model, and these data were used to calculate sedimentation rates and sediment accumulation rates, which were compared with environmental variables. Age-depth profiles indicated that sedimentation rates changed at different times in different marshes, and we separated sediment cores into two parts to show sediment characteristic and sediment-accumulation-rate changes. Ranges of dry mass accumulation rates and sedimentation rates were 0.081-1.356 kg m Ϫ2 yr Ϫ1 and 0.94-4.64 mm yr Ϫ1 in the upper core and 0.094-0.563 kg m Ϫ2 yr Ϫ1 and 0.57-1.75 mm yr Ϫ1 in the lower core. In general, the cores showed recent increases in sediment accumulation rates. Species composition was related to water quality, with the dominant species changing in a predictable series with decreasing water quality: Nuphar, Nuphar and Carex/Scirpus, Eleocharis, Potamogeton, Ranunculus, and Chara. The effect of a rough road used for timber transport was observed as the change of sediment accumulation rates in Upper Grass Lake. Sediment accumulation rates since the improvement of the rough road decreased to ca. 80 % of those prior to the improvement. Road-salt use was related to relatively high water cation concentrations and conductivity in Meyers Grade Marsh adjacent to Hwy 50. Increased lead accumulation rates and concentrations in more recent sediments at Meyers Grade Marsh and Snow Creek reflect the increasing use of fossil fueled vehicles in this region. Urbanization and animal farming were related to increased N and P concentrations in marsh water. The number of exotic plant species within a marsh was highly correlated with water quality and C and N accumulation rates. This study showed that 8 of the 11 marshes studied are in relatively undisturbed condition, while the remaining 3 have been heavily impacted. Urbanization and increased recreation facilities, and activities are important anthropogenic impacts on subalpine marshes. This study suggests that pristine subalpine marshes be protected from increasing human activities and that marshes impacted by rough roads can be restored to pristine conditions.

- by Eliska Rejmankova
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- Earth Sciences, Wetlands, Water quality, Exotic Species

We examined size-mass allometry and biomass allocation of two larch species (Larix gmelinii (Rupr.) Rupr. and Larix cajanderi Mayer) that grow on the continuous permafrost regions in Siberia. Sample tree data (total n = 27) gathered from four mature stands (>100 years old) were employed for analysis. First, to determine good size predictor of biomass, site-specific allometric relationships (log-linear equation form) were derived between dry mass of four components (stem, branch, needle and coarse root; !5 mm in diameter) and seven size variables; stem diameters (breast height, 30 cm height and crown base), sapwood areas (breast height and 30 cm height), and two combined-variables (tree height Â diadiameter). For all components, site-specific allometric equations based on breast-height diameter (D) always gave high correlations as those using other size variables. However, between-stand comparisons of the D-base site-specific allometry indicated that size dependency (i.e., regression slope) differed for stem mass. Besides, needle and coarse root mass for a given size (i.e., regression intercept) differed significantly among the four stands. These facts implied that D-base regression model was reliable for biomass estimation by site-specific allometry, but was not suitable for developing general (i.e., site-common) allometry. Second, to examine carbon allocation pattern, we estimated each stand biomass by applying corresponding site-specific D-base allometry. Stand total biomass ranged from 8.6 to 33.1 Mg ha À1 , and aboveground-total/coarse root biomass ratio (i.e., T/R) ranged from 1.5 to 2.6. The variation was mainly due to trade-offs between stem and root biomass. Average T/R was about 2.3 that was calculated for some reported L. gmelinii and L. cajanderi stands (n = 16), including our four stands. This average T/R was extremely small in comparison to that (5.1) of Scots pine (Pinus sylvestris L.) stands on the non-or discontinuous permafrost regions in Siberia. This finding strongly suggested that the two Larix species invested annual carbon gains largely into root growth. We discussed its ecological implications in relation to stand structure and permafrost soil-N conditions in the larch taiga ecosystem. #

- by Takayoshi Koike and +1
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- Forest Ecology And Management, Biological Sciences, Environmental Sciences, Carbon Allocation

We examined the occurrence of marine debris in the gastrointestinal tract of 54 loggerhead sea turtles (Caretta caretta) found stranded or incidentally captured dead by fisheries in the Adriatic Sea, with a curved carapace length of 25.0–79.2 cm. Marine debris was present in 35.2% of turtles and included soft plastic, ropes, Styrofoam and monofilament lines found in 68.4%, 42.1%, 15.8% and 5.3% of loggerheads that have ingested debris, respectively. The dry mass of debris per turtle was low, ranging from <0.01 to 0.71 g, and the ingestion was not significantly affected by sex or body size (all p > 0.05). Marine debris averaged 2.2 ± 8.0% of dry mass of gut content, with a maximum of 35% found in a juvenile turtle that most likely died due to debris ingestion. Considering the relatively high occurrence of debris intake and possible sub-lethal effects of even small quantities of marine debris, this can be an additional factor of concern for loggerheads in the Adriatic Sea.► Marine debris was ingested by 35.2% loggerheads foraging in neritic habitats of the Adriatic. ► Soft plastic was the most frequent type of debris found in digestive tract. ► Debris ingestion was not significantly affected by sex or body size of turtles. ► High occurrence of debris intake represents a factor of concern for loggerheads in the Adriatic Sea.

- by Romana Gracan
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- Mediterranean, Environmental Monitoring, Water Pollution, Multidisciplinary

Water for irrigation is limited worldwide. Therefore water saving practices will have to be adopted. This experiment was carried out to compare deficit irrigation (DI) with partial rootzone drying (PRD) for their effects on the processing tomato (Lycopersicon esculentum Mill.) cv. Petopride. The treatments were: full watering of both sides of the root system (RS) at each irrigation as control (C), half of irrigation water in C divided equally to both sides of the RS with each watering (DI), and half of irrigation water in C given only to one side of the RS with each irrigation (PRD). Photosynthetic rate, transpiration, stomatal conductance, and leaf water potential were measured on five occasions, and were found to be the same among treatments. Total fruit fresh mass

- by Jorge Zegbe
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- Water Saving, Tomato, Irrigation Water, Water Conservation

Crops respond to N deficiency through a reduction in resource capture and/or resource use efficiency. The objective of this paper is to examine whether differences in this response pattern are associated with either metabolic group (C 3 vs. C 4 ) or botanical classification (mono-vs. dicotyledons). Hereto, we analysed the effect of N deficiency on the relationships between N uptake, LAI, and biomass accumulation, for maize, sorghum, wheat, canola, tall fescue, and sunflower, grown in experiments in either France or Australia. Maize and tall fescue maintained LAI per unit biomass (measure of resource capture) at the expense of N uptake per unit LAI (measure of resource use efficiency). Wheat and canola had the opposite response, whereas sunflower and sorghum were intermediate. In general, C 4 species reduced N uptake per unit LAI more than C 3 species. Species differences in the effect of N deficiency on resource use efficiency were associated with differences in the SLN or in the N storage capacity of the stems. For wheat, canola, and tall fescue, SLN declined with increasing LAI under high N conditions, and the minimum crop SLN under N deficiency was only marginally lower than under high N conditions. For sorghum, sunflower, and maize, crop SLN under high N changed little with increasing LAI, but the minimum crop SLN under N deficiency was considerably lower than under high N. Sorghum and maize were the only species that substantially decreased stem N uptake per unit LAI under N deficiency. Overall, our data suggest that C 3 species are better able to maintain resource use efficiency under N stress than C 4 species, and a survey of literature suggests this may be because in C 4 species, the critical SLN for radiation use efficiency is higher than the critical SLN for leaf expansion, whereas the opposite is the case for C 3 species. We hypothesise that species differences in response to N deficiency could be associated with these differences in critical SLN, which in turn could be a consequence of the lower photosynthetic nitrogen use efficiency of C 3 crops. #

- by Marie-hélène Jeuffroy
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- Resource use, Maize, Sorghum, Field Crops

As trees are planted in close proximity to properties and humans in a dense city like Singapore, uprooting of trees can pose safety concerns. Previous research studies have shown that soil properties are important factors that govern tree stability. Soil properties can be improved by mixing top soil (TS) with coarse-grained soil. The effects of soil improvement using coarse-grained soil on tree stability were investigated in this study. Granite chip was used as coarsegrained soil to improve the original top soil. Static analysis and finite element modeling were performed to study tree stability in an improved soil. Factors investigated include root geometry and soil shear strength parameter. Finite element results showed good agreement with static analysis in determining the maximum wind force needed to uproot the tree. Parametric study showed that the wind force needed to uproot the tree was influenced by the mode of failure and the magnitude was dependant on the root geometry and the soil properties. A mixture of 20% top soil and 80% granite chip by dry mass was the optimum mixture for withstanding the maximum wind force needed to uproot the tree.

- by Harianto Rahardjo
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- Static Analysis, Urban Forestry, Finite Element, Forestry Sciences
- by Ülo Niinemets
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- Photosynthesis, Biological Sciences, Woody Plants, Dry Mass

This study involves three species of the family Orobanchaceae: Cistanche phelypaea, C. tubulosa and Orobanche cernua. These species are obligate perennial root parasites. They may occur together infecting hosts growing in the following phytogeographical regions: (1) along the Mediterranean coastal belt in deep oolitic limestone sand dunes and in loamy salt affected ground;

Polyhydroxyalkanoate (PHA) is a family of biopolymers produced by some bacteria and is accumulated intracellularly as carbon and energy storage material. Fifteen PHA-producing bacterial strains were identified from bacteria isolated from Antarctic soils collected around Casey Station (66°17′S, 110°32′E) and Signy Island (60°45′S, 45°36′W). Screening for PHA production was carried out by incubating the isolates in PHA production medium supplemented with 0.5% (w/v) sodium octanoate or glucose. 16S rRNA gene sequence analysis revealed that the isolated PHA-producing strains were mainly Pseudomonas spp. and a few were Janthinobacterium spp. All the isolated Pseudomonas strains were able to produce medium-chain-length (mcl) PHA using fatty acids as carbon source, while some could also produce mcl-PHA by using glucose. The Janthinobacterium strains could only utilize glucose to produce polyhydroxybutyrate (PHB). A Pseudomonas isolate, UMAB-40, accumulated PHA up to 48% cell dry mass when utilizing fatty acids as carbon source. This high accumulation occurred at between 5 °C and 20 °C, then decreased with increasing temperatures. Highly unsaturated mcl-PHA was produced by UMAB-40 from glucose. Such characteristics may be associated with the ability of UMAB-40 to survive in the cold.

- by Irene Tan Kit Ping
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- Microbiology, Carbon, Medical Microbiology, Sequence Analysis

A field test of wych elm (Ulmus glabra Huds.) trees micropropagated in tissue culture was established to compare their photosynthetic characteristics with those from control grafted scions. Measurements were made at the sixth growing season after planting. The results showed similarities between the two stock types in terms of height, diameter at breast height, and leaf morphology. Grafted trees, which were markedly less rejuvenated than micropropagated trees, performed better in many of the light absorption and leaf gas exchange attributes including maximum CO 2 assimilation rate at saturating photosynthetic photon flux density (P max ), apparent quantum yield of photosynthesis (a), transpiration rate (E), and stomatal conductance (g s ). In the grafts, the direct effect of photosynthesis could be clearly identified by a significantly lower specific leaf area and a higher content of leaf dry mass. Chlorophyll a fluorescence parameters showed nonstressed growth patterns in both stock types. Rates of the maximal photochemical efficiency of photosystem II (F v /F m ), potential electron capacity ('area'), and variable-to-initial fluorescence ratio (F v /F 0 ) were higher in micropropagated elms. Findings from this study indicate that micropropagated elm stock is ready for testing on a larger scale.

- by Tibor Priwitzer
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- Plant Biology, Tissue culture, Chlorophyll Fluorescence, Leaf Morphology

When corn grain moisture was in the typical harvest range of 30 and 20%, the ratio of stover dry mass to whole-plant dry mass averaged 43%. The moisture in the stalk remained over 65% until grain harvest. The ratio of mass of stover harvested to total stover DM yield, averaged about 53, 56 and 33% for chopping, wet baling and dry baling, respectively. Harvesting wet stover as chopped material and ensiling in a silo bag was successful with DM matter loss at 10.9% after seven months storage. Harvesting wet stover by baling and tube wrapping was also successful with DM loss of 3.6%. Dry stover bales stored indoors and outdoors had average DM losses of 5 and 15%, respectively. Wrapping dry bales in net wrap and storing on a well drained surface significantly reduced DM loss compared to storing twine wrapped dry bales on the ground.

- by Philippe Savoie
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- Dry Mass

Creatine is a naturally occurring compound that is synthesized endogenously and is present in a meat eaters diet. It is stored in abundance in skeletal muscle, where it exists in free and phosphorylated forms and plays a pivotal role in maintaining a high adenosine triphosphate:adenosine diphosphate ratio during intense contraction. Fatigue development during short-term maximal exercise has been associated with the inability of skeletal muscle to maintain this ratio, at least partly because of phosphocreatine depletion. Ingestion of creatine monohydrate in solution at a rate of 20 g/day for 5 to 6 days has been shown to increase muscle total creatine concentration by approximately 25 mmobkg dry mass in man, but the variation between subjects is large. After this initial loading phase, muscle stores can be maintained by ingesting 2 g/day. A positive relationship has since been demonstrated between muscle creatine uptake and improvements in pe$ormance during repeated bouts of maximal exercise and rates of phosphocreatine resynthesis during recovery from maximal exercise. The mechanism by which improvements in maximal exercise pe$ormance are achieved following creatine ingestion possibly relates to an increase in phosphocreatine concentration, specifically in Type II muscle fibres, maintaining adenosine triphosphate resynthesis during exercise. Recently, muscle creatine accumulation has been shown to be substantially increased by combining creatine supplementation with carbohydrate ingestion, elevating muscle creatine concentration in all subjects close to the upper limit of 160 mmobkg dm. Creatine supplementation should be viewed as a significant development in sports-related nutrition.

- by Paul Greenhaff
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- Nutrition and Dietetics, Nutrition, Biology, Performance

A theoretical analysis of the drying process occurring inside the household electric tumbler clothes-dryer is performed to determine various thermo-physical parameters affecting the energy consumption and for the development of a simulation model. Experiments are conducted on a test set-up, based on a compact tumble-dryer, to measure the values of the parameters necessary for evaluating the performance. Widely-accepted economy standards are considered for comparison of simulation and experimental results. The simulation results are in reasonable agreement with experimental data. An empirical correlation for the specific moisture-extraction rate (SMER) is developed to translate energy-consumption information from one standard to the other.

- by vikas yadav
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- Engineering, Economics, Energy Consumption, Theoretical Analysis

Despite its antioxidant capacity and well-known health benefits, yerba mate tea (Ilex paraguariensis) has been shown to possess some genotoxic and mutagenic activities and to increase incidence of some types of cancer. The aim of this study was to estimate the cyto- and genotoxicity of mate tea in human peripheral lymphocytes in vitro. We found that yerba mate extract induced a concentration-dependent, statistically significant increase in the level of apoptotic and necrotic cells and a decrease in the nuclear division index (NDI). Mate-exposed lymphocytes had a reduced transcriptional rDNA activity, which may be due to the stress conditions, and showed an elevated production of micronuclei. The FISH technique revealed the appearance of an acrocentric signal in mate-induced micronuclei, which suggests that under these conditions yerba mate extract may display aneugenic activity. Since caffeine is one of the most abundant compounds found in the dry mass of mate, we conducted additional experiments with caffeine alone. We showed that caffeine used at the same concentrations manifests a more potent cyto- and genotoxic effect that may account, at least in part, for the disadvantageous effects observed for yerba mate extract.

- by Maciej Wnuk
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- Genetics, Toxicology, Genetic Toxicology, DNA damage

Effects of Osmotic dehydration on mass transfer properties as water loss, solids gain, and weight reduction during osmotic dehydration were investigated in order to determine the usefulness of this technique as pre-treatment for further drying of bananas slices. Banana slices, 10 mm thick, were immersed in sucrose solutions with concentrations of 45, 55 and 65 Brix at 30, 40 and 50 o C for 20, 40, 60,120 and 240 minutes. Water loss, weight reduction and solids gain increased with treatment time. Longer treatment time in high concentrations of sucrose resulted in a very soft product, which is difficult to handle and unsuitable for further drying. Increasing concentration at the same temperature did not cause significant increments in weight change. Higher concentrations of sucrose caused higher rates of water removal. About 50% of the water loss occurred between 40 -120 minutes for most of the conditions. This technique can be used to produce good product for further drying. Results obtained suggest that a product for further drying could be obtained by treating the slices at temperatures not more than 30 o C and using osmotic solutions at 55 or 65 Brix.

- by Ana Andrés
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- Mass Transfer, The, Water Loss, Osmotic Dehydration

Lake Hayq, a highland lake in Ethiopia, was stocked with Tilapia fish (Oreochromis niloticus) in late 1970s, offering an opportunity to study the effect of fish predation in a natural lake. Since 1930s, some limnological surveys have been done sporadically documenting a change in zooplankton composition including the disappearance of cladocerans, hypothesizing the stocked planktivorous fish could be a cause. Nevertheless, no detailed research was conducted to identify potential effects of fish stocking predominantly due to its remote location. The article presents data about zooplankton composition, abundance and biomass done between October 2007 and January 2009 on short-time intervals including the underlying limnological variables. The zooplankton community was depauperate comprising two copepods, three cladocerans, and six rotifers taxa, as typical for tropical lakes. Total mean standing biomass of all crustacean zooplankton was 237 mg dry mass m −3 , which gave Lake Hayq an intermediate position when compared with other tropical lakes. Of copepods, Thermocyclops ethiopiensis was almost an exclusive species, and its temporal variation was influenced by food supply and water temperature. We refute the hypothesis that Tilapia was the cause for the seasonal disappearance of cladocerans, and attribute it to the adverse effect of episodic mixing. Nevertheless, the planktivorous fish probably plays a key role in structuring the cladocerans in particular the large-sized Daphnia magna. In January 2008, we observed a massive planktivorous fish mortality that triggered high algal biomass, which was later grazed by large-sized D. magna demonstrating the trophic cascade hypothesis in a natural ecosystem.

- by Tadesse Fetahi and +1
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- Ecology, Mixing, Seasonality, Food supply

The technique of phytomining involves growing a crop of a metal-hyperaccumulating plant species, harvesting the biomass and burning it to produce a bio-ore. The first phytomining experiments were carried out in California using the Ni-hyperaccumulator Streptanthus polygaloides and it was found that a yield of 100 kg=ha of sulphur-free Ni could be produced. We have used the same technique to test the phytomining potential of the Ni-hyperaccumulators Alyssum bertolonii from Italy and Berkheya coddii from South Africa. The effect of different fertiliser treatments on growth of Alyssum bertolonii was established in situ in Tuscany and showed that the biomass of the plant could be increased by a factor of nearly 3 (4.5 t=ha to 12 t=ha) without significant loss of the Ni concentration (7600 mg=kg) in the plant. Analogous experiments have been carried out on Berkheya coddii where a biomass yield of over 20 t=ha can readily be achieved though the Ni concentration is not as high as in A. bertolonii. The total yield is, however, much greater. We have also been able to induce plants to hyperaccumulate Au by adding ammonium thiocyanate to the substrate. Up to 57 mg=kg Au (dry mass) could be accumulated by Indian mustard (Brassica juncea). Unusual hyperaccumulation (>500 mg=kg dry mass) of Tl has been determined in Iberis intermedia and Biscutella laevigata (Brassicaceae) from southern France. The Iberis contained up to 0.4% Tl (4000 mg=kg) in the whole-plant dry matter and the Biscutella over 1.5%. This unusually high accumulation of Tl has significance for animal and human health, phytoremediation of contaminated soils, and phytomining for Tl. We calculate that using Iberis, a net return of $ US 1200=ha (twice the return from a crop of wheat) would be possible with a biomass yield of 10 t=ha containing 0.08% Tl in dry matter. The break-even point (net yield of $ US 500=ha) would require 170 mg=kg (0.017%) Tl in dry matter. A model of a phytomining operation and its economics is presented and its advantages and disadvantages discussed.

- by Robyn Simcock
- •
- Geology, Geochemistry, Phytoremediation, South Africa

One method for economic planning and management of production processes is a balance of substrate mass and energy it contains. Theoretical assumptions and practical applications of mass and energy balances in the process of citric acid production by Aspergillus niger are discussed in the study.In the calculation of biomass and product yields as well as the maintenance coefficients mechanistic values such as true biomass and citric acid yields YmaxATP,X(P) on ATP and specific ATP consumption mATP due to maintenance processes were used. A set of limitations imposed on theoretical and true yield coefficients in the linear growth equation is also presented.The experimental measurements were performed in an air-lift bioreactor of 220 dm3 operating capacity, with external circulation loop. The sole carbon source for the cultivation of A. niger was sucrose at an initial concentration of 100 g l−1.The experimentally obtained yield coefficients relative to cell growth and citric acid production have reached 96% and 83% respectively of real maximum theoretical values. Calculated true biomass and citric acid yield coefficients were closely correlated with the values from the balance analysis of stoichiometric equations. Calculated value of specific maintenance requirements mATP was 0.015 mol ATP [mol C(dry mass)]−1 h−1.

- by Stanislaw Ledakowicz and +1
- •
- Energy Balance, Aspergillus niger, Production Process, Experimental Measurement

The aim of this paper is to report potato moisture diffusivity data determined from experimental convective drying kinetics. Two different methods have been applied to evaluate this coefficient. The first one was based on the analytical solution of a fickian diffusive model which enabled diffusivity determination by simple linear regression over experimental data. The regression was done using the real sample thickness in order to account for shrinkage. The second one was based on a numerical solution of solid mass balance equation and moisture transfer diffusion/convection equation, these equations being coupled by the solid phase velocity due to shrinkage. At each time step of the simulation, the diffusivity was adjusted to minimize the difference between calculated and measured sample mean moisture content. Due to several simplifying hypothesis the first method could only provide approximate results, while the second could be considered as reference. Predictive correlations for moisture diffusivity as function of temperature and moisture content are presented.

- by Abdelfettah Belghith
- •
- Food Engineering, Potato, Diffusion Coefficient, Moisture Content

Inert or dry mass in aerospace systems has historically grown during aerospace vehicle development because of a number of factors: changing requirements, uncertainty in the performance of the initial technology selection, addition of redundancy, errors in the original design, as well as uncertain masses and loads. In the case of exploration architectures for lunar missions, compounding effects of a multi-staged mission design makes mass-efficient vehicles a necessity for achieving the total delta-V performance required to reach the lunar surface and return to Earth. Current standards and guidelines for mass growth risk mitigation are compared, including the industry and NASA standard methods for risk management and mitigation through the application of mass margin. Historical mass growth trends are analyzed, and average levels of growth are compared to the standard margin allocation levels. Analysis of the available historical data shows that the mean inert mass growth is 28%, and 30% of historical programs experience inert mass growth in excess of the allowable growth and margin recommended level of 32.5%. As an illustrative example of the mass growth of lunar exploration architectures the mass growth sensitivity of the Apollo architecture is calculated. Results show that a kilogram of mass growth on the lunar ascent stage is compounded over 800 times in gross mass.

- by Alan Wilhite
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- Mechanical Engineering, Aerospace Engineering, Risk Management, System Architecture

The present study reviews the options of cultivating the green alga, Chlorella emersonii, under photoautotrophic conditions with flue gas derived from a cement plant. It was conducted in the Lafarge Perlmooser plant in Retznei, Austria, where stone coal and various surrogate fuels such as used tyres, plastics and meat-and-bone meal are incinerated for heating limestone. During 30 days of cultivation, flue gas had no visible adverse effects compared to the controls grown with pure CO2. The semi-continuous cultivation with media recycling was performed in 5.5-L pH-stat photobioreactors. The essay using CO2 from flue gas yielded a total of 2.00 g L−1 microalgal dry mass and a CO2 fixation of 3.25 g L−1. In the control, a total of 2.06 g L−1 dry mass was produced and 3.38 g L−1 CO2 was fixed. Mean growth rates were between 0.10 day−1 (control) and 0.13 day−1 (flue gas). No accumulation of flue gas residues was detected in the culture medium. At the end of the experiment, however, the concentration of lead was three times higher in algal biomass compared to the control, indicating that cultures aerated with this type of flue gas should not be used as food supplements or animal feed.

- by michael schagerl
- •
- Biotechnology, Plant Biology, Environmental Biotechnology, Applied

The African bread fruit is produced by Treculia, a wild tropical evergreen tree and has immense potential as a nutritional source for man. We evaluated its chemical and nutritional properties as a first step in realizing its food value. The seed [Dry Mass (DM) basis] contained 8% moisture, 12.5% crude protein, 4.2% fat 2.3% ash 1.6% fibre and 73% carbohydrate. The carbohydrate and protein contents in it were much higher than other parameters studied. Compositions of toxicants in seeds were quite low with levels (mg/100 g) of 0.06±0.12 for hydrocyanide 3.0±0.11 for oxalate and 0.76±0.01 for phytate. For mineral elements, the contents (mg/100 gDM) were 587±0.2 for potassium (K), 186±0.2 for Magnesium (Mg) and 850±0.02 for zinc (Zn). The sodium (Na), Calcium (Ca), iron (Fe) and Copper (Cu) contents were negligible. Results of phytochemical screening of the extract showed, that it contained appreciable amounts of flavonoid, polyphenols, anthraquinones, saponins and cardiac glycosides. These secondary metabolites are known to have microbial activity as well as other physiological activity.

- by peter Okafor (pexgraphics)
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- Nutrition and Dietetics, Pakistan, Magnesium, Copper

The grapevine (Vitis vinifera L. cv. Riesling) plants subjected to water deficit were studied for changes in relative water content (RWC), leaf dry mass, contents of chlorophyll (Chl), total leaf proteins, free amino acids, and proline, and activities of ribulose-1,5-bisphosphate carboxylase (RuBPC), nitrate reductase (NR), and protease. In water-stressed plants RWC, leaf dry matter, Chl content, net photosynthetic rate (P N), and RuBPC and NR activities were significantly decreased. The total leaf protein content also declined with increase in the accumulation of free amino acids. Concurrently, the protease activity in the tissues was also increased. A significant two-fold increase in proline content was recorded.

- by Massimo Bertamini
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- Plant Biology, Water Stress, Nitrate Reductase, Physiological Response

Both parallel fermentations with Aspergillus awamori (CBS 115.52) and a literature study on several fungi have been carried out to determine a relation between fungal morphology and agitation intensity. The studied parameters include hyphal length, pellet size, surface structure or so-called hairy length of pellets, and dry mass per-wet-pellet volume at different specific energy dissipation rates. The literature data from different strains, different fermenters, and different cultivation conditions can be summarized to say that the main mean hyphal length is proportional to the specific energy dissipation rate according to a power function with an exponent of −0.25 ± 0.08. Fermentations with identical inocula showed that pellet size was also a function of the specific energy dissipation rate and proportional to the specific energy dissipation rate to an exponent of −0.16 ± 0.03. Based on the experimental observations, we propose the following mechanism of pellet damage during submerged cultivation in stirred fermenters. Interaction between mechanical forces and pellets results in the hyphal chip-off from the pellet outer zone instead of the breakup of pellets. By this mechanism, the extension of the hyphae or hair from pellets is restricted so that the size of pellets is related to the specific energy dissipation rate. Hyphae chipped off from pellets contribute free filamentous mycelia and reseed their growth. So the fraction of filamentous mycelial mass in the total biomass is related to the specific energy dissipation rate as well.

- by Yi-Qing Cui and +1
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- Multidisciplinary, Surface Morphology, Energy Dissipation, Surface Structure
- by Michael Watt and +2
- •
- Plant Biology, Trees, Dry Matter Partitioning, Physiological Response

Antagonistic fungi (Aspergillus niger CA and Penicillium chrysogenum CA1), plant growth-promoting rhizobacteria (PGPR) (Burkholderia cepacia 4684 and Bacillus subtilis 7612) and AM fungi (Glomus intraradices KA and Gigaspora margarita AA) were assessed alone and in combination for their effects on the growth of tomato and on the reproduction of Meloidogyne incognita in glasshouse experiments. Application of antagonistic fungus, PGPR, or AM fungus alone or in combination significantly increased the length and shoot dry mass of plants both with and without nematodes. The increase in shoot dry mass caused by Gl. intraradices KA in plants without nematodes was greater than that caused by PGPR or antagonistic fungi. Similarly, the increase in shoot dry mass caused by Bu. cepacia 4684 in plants with nematodes was greater than that caused by P. chrysogenum CA1. Application of Bu. cepacia 4684 caused a 36.1% increase in shoot dry mass of nematode-inoculated plants followed by Ba. subtilis 7612 (32.4%), A. niger CA (31.7%), Gl. intraradices KA (30.9%), Gi. margarita AA (29.9%) and P. chrysogenum CA1 (28.8%). Use of Bu. cepacia 4684 with A. niger CA caused a highest (65.7%) increase in shoot dry mass in nematode-inoculated plants followed by Ba. subtilis 7612 plus A. niger CA (60.9%). Burkholderia cepacia 4684 greatly reduced (39%) galling and nematode multiplication, and the reduction was even greater (73%) when applied with A. niger CA. Antagonistic fungi had no significant effect on root colonization caused by AM fungi. Applying Bu. cepacia 4684 with A. niger CA may be useful in the biocontrol of M. incognita on tomato.

- by Mohd Sayeed and +1
- •
- Microbiology, Plant Biology, Arbuscular mycorrhizal fungi, AM fungi

Field experiments were conducted during 2007–2009 to study the effect of deficit irrigation practices through drip irrigation system on soil moisture distribution and root growth in cotton–maize cropping sequence. Creation of soil moisture gradient is indispensable to explore the beneficial effects of partial root zone drying (PRD) irrigation and it could be possible only through ADI practice in paired row system of drip layout, that is commonly practiced in India. In the present study, PRD and deficit irrigation (DI) concepts (creation of soil moisture gradient) were implemented through alternate deficit irrigation (ADI) at two levels of irrigation using drip system. Experimental treatments comprised of six irrigation levels (full and deficit) through drip system with surface irrigation for comparison. Maize was sown after cotton under no till condition without disturbing the raised bed and drip layout. Roots confined to the shallow depth and recorded the lowest values for both the crops under conventional drip irrigation at 100% ETc. Among the deficit irrigation treatments, mild deficit irrigation produced longer lateral roots from both the sides of the plant. Contrary to rooting depth, severe water stress affected the lateral root spread and recorded lower values than other drip irrigation treatments. Soil moisture content (SMC) was low nearer to the plant (at 30 cm across the lateral) and far away (at 30 cm along the lateral) from the plant, irrespective of treatments. The reduction in SMC was increased at all locations as applied water level decreased. It is concluded that alternate watering imposed through ADI at 100% ETc produced longer lateral roots with higher values for root dry mass Alternate deficit irrigation (ADI) resulted uneven distribution of soil moisture content. Among the ADI treatments, ADI at 100% had less uneven distribution than ADI at 80% ETc.► Alternate deficit irrigation (ADI) resulted uneven distribution of soil moisture content. ► ADI at 100% ETc had less uneven distribution than at 80% ETc. ► Soil moisture content was decreased at all locations as water applied decreased. ► Roots confined to the shallow depth under conventional drip irrigation. ► Rooting depth was increased as water stress increased and ADI promotes more secondary active roots.

- by T Sampathkumar
- •
- Civil Engineering, Agricultural Water Management, Soil moisture, Maize

Our aim was to quantify climatic influences on key leaf traits and relationships at the global scale. This knowledge provides insight into how plants have adapted to different environmental pressures, and will lead to better calibration... more

- by Ian Wright
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- Principal Component Analysis, Photosynthesis, Ecology, Temperature

Shoot cultures of the cardenolide-producing species Digitalis lanata Ehrh. accumulated up to 0.6 0rnol cardenolides per g dry mass when cultivated under continuous white light. After transfer to permanent dark, the cardenolide content of cultured shoots gradually decreased and reached non-detectable levels after 12 weeks. After transfer back to light conditions, cardenolides started to accumulate and reached the levels of light-grown controls after 4 weeks. Radiolabelled pregnenolone and progesterone were incorporated into cardenolides in both green light-grown and white dark-grown shoots. It was thus established that cardenolides are synthesised de novo in chloroplast-free tissues without apparent cardenolide accumulation, indicating that these compounds are efficiently turned over in the dark and that tissue differentiation, but not intact chloroplasts, is essential for cardenolide formation. The time course of two late anabolic enzymes of cardenolide metabolism, acetyl-CoA:digitoxin 15'-0acetyltransferase (DAT, EC 2.3.1.-) and UDP-glucose:digitoxin 16'-glucosyltransferase (DGT, EC 2.4.1.-) was established during transfer of shoots from light to dark and vice versa. Only DAT was affected and was not measurable any more under dark conditions. The DGT may not be down-regulated because of its important, maybe even vital, role as an enzyme providing the vacuolar storage forms of cardenolides. Two catabolic cardenolide-specific enzymes, lanatoside 15'-O-acetylesterase (LAE, EC 3.1.1.6.) and cardenolide 16'-O-glucohydrolase t (CGH I, EC 3.2.1.21), were also investigated and it was demonstrated that CGH I is inactive in dark-grown shoots. These observations indicate that CGH I is not involved in cardenolide degradation in situ, but may instead play a role in cardenolide remetabolisation and activation after wounding or in developmental programs. © Elsevier, Paris Biosynthesis / cardiac glycosides / Digitalis lanata / enzymes / pregnenolone / progesterone / shoot cultures BAP, 6-benzylamino purine / CGH I, cardenolide 16'-O-glucohydrolase I / DAT, acetyi-CoA:digitoxin 15'-O-acetyltransferase / DGT, UDP-glucose:digitoxin 16'-glucosyltransferase / DMSO, dimethylsulphoxide / DW, dry weight / EDTA, ethylenediaminetetraacetic acid ! HPLC, high pressure liquid chromatography ! IAA, indoleacetic acid / LAE, lanatoside 15'-O-acetylesterase ! LSC, liquid scintillation counting / Pe, pregnenolone / Po, progesterone ! Rf, relative migration tract / RIA, radioimmunoassay / TLC, thin layer chromatography

- by Wolfgang Kreis
- •
- Plant Biology, Tissue culture, Light, Soil sciences

Calystegines were identified in the genus Erythroxylum for the first time. Erythroxylum novogranatense var. novogranatense, a species cultivated for cocaine production, contained 0.2% total calystegines in dry leaves. Forty six Erythroxylum herbarium species consisting mostly of leaf tissue were analysed for calystegines, and 38 were found positive. Calystegines were compared qualitatively and quantitatively between individual Erythroxylum species. Calystegines A 3 and B 2 were the major calystegines in most species. Total calystegine content reached up to 0.32% dry mass. The simultaneous occurrence of calystegines, cocaine, other alkaloids of a 3a-hydroxy-or 3b-hydroxytropane structure together with nicotine supports the concept of common biosynthetic steps of these alkaloids in Erythroxylum. The present results are the basis for further investigations of the phylogenetic origin of tropane alkaloid biosynthesis in the taxonomically remote families Solanaceae and Erythroxylaceae.

- by Philippe Christen
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- Phytochemistry, Taxonomy, Biological Sciences, Phylogeny

To determine pseudopterosin composition and concentration in colonies of Pseudopterogorgia elisabethae from the islands of San Andres and Providencia, we collected fragments of individual colonies at various sites and depth ranges around the islands. Chromatographic profiles of the polar fraction, particularly those obtained by HPLC-MS analyses, allowed us to recognize two different chemotypes. Chemotype 1 characterized samples from Providencia whereas chemotype 2 characterized samples from San Andres. A complex pseudopterosin mixture (compounds 1-13) characterized chemotype 1. These compounds were isolated by a combination of chromatographic methods and identified by spectroscopic methods (MS, UV, 1 H, and 13 C NMR). We identified the known pseudopterosins G and K and seco-pseudopterosin A. We also isolated and identified seven new compounds, pseudopterosins P-V, isomers of known pseudopterosins. Pseudopterosins G and K were found at concentrations ranging between 1 and 3% of the animal dry mass. Pseudopterosins Q and U were the major compounds reaching up to 6% of the animal dry mass at some locations. Major metabolites in chemotype 2 had a molecular weight and fragmentation pattern different from that observed in the pseudopterosins, as determined by HPLC-MS. Total pseudopterosin concentration in this chemotype was below 3% dry mass at all sites. Total pseudopterosin concentration was significantly higher in chemotype 1, with concentrations ranging between 4 and 20% dry mass. At most locations on Providencia, however, total pseudopterosin concentration ranged between 11 and 15% dry mass. Concentrations exceed reports from other locations in the Caribbean. Furthermore, pseudopterosin composition in our samples is quite different from those in specimens of P. elisabethae from the Bahamas and Bermuda. Pseudopterosins G, K, and P-V are characteristic of P. elisabethae colonies from the island of Providencia, while pseudopterosins A-D are characteristic of colonies of P. elisabethae from the Bahamas islands, and pseudopterosins E-L have been isolated from P. elisabethae from the Bahamas and Bermuda. The overall morphology of P. elisabethae can be variable, and chemical differences are not correlated to specific morphs. We confirmed the species identity of each colony by morphological and sclerite analysis and found no significant differences in sclerite dimensions among different colonies and chemotypes.

- by Alejandro Paz
- •
- Geography, Chemical Ecology, Chemical, Biological Sciences

Abstraet. An obligately anaerobic, rod-shaped bacterium was isolated on alanine in co-culture with H2-scavenging Desulfovibrio and obtained in pure culture with glycine as sole fermentation substrate. The isolated strain, al-2, was motile by a polar to subpolar flagellum and stained Grampositive. The guanine plus cytosine content of the DNA was 44.0 mol %. Strain al-2 grew in defined, reduced glycine media supplemented with biotin. The pure culture fermented 4 mol glycine to 3 mol acetate, 4 mol ammonia and 2 tool CO2. Under optimum conditions (34~ pH7.3), the doubling time on glycine was 60 min and the molar growth yield 7.6 g cell dry mass. Serine was fermented to acetate, ethanol, CO2, H2 and ammonia. In addition, betaine, sarcosine or creatine served as substrates for growth and acetate production if H2, formate or e.g. valine were added as H-donors. In pure culture on alanine under N2, strain al-2 grew very poorly and produced H2 up to a partial pressure of 3.6 kPa (0.035 atm). Desulfovibrio species, Methanospirillum hungatei and Acetobacterium woodii served as H2-scavengers that allowed good syntrophic growth on alanine. The co-cultures also grew on aspartate, leucine, valine or malate. Alanine and aspartate were stoichiometrically degraded to acetate and ammonia, whereas the reducing equivalents were recovered as H2S, CH~ or newly synthetized acetate, respectively. Growth of strain al-2 in co-culture with the hydrogenase-negative, formate,utilizing Desulfovibrio baarsii indicated that a syntrophy was also possible by interspecies formate transfer. Growth on glycine, or on betaine, sarcosine or creatine (plus H-donors) depended strictly on the addition of selenite (_>0.1 IxM); selenite was not required for fermentation of serine, or for degradation of alanine, aspartate or valine by the co-cultures. Cell-free extracts of glycine-grown cells contained active glycine reductase, glycine decarboxylase and reversible methyl viologen-dependent formate dehydrogenase in addition to the other enzymes necessary for an oxidation to CO2. In all reactions NADP was the preferred H-carrier. Both formate and glycine could be synthesized from bicarbonate. Serine-grown cells did not contain serine hydroxymethyl transferase but serine dehydratase and other enzymes commonly involved in pyruvate metabolism to acetate, CO2 and H2. The enzymes involved in glycine metabolism were repressed during growth on serine. By its * Present address: Mikrobiologie, FB Biologie, Philipps Universitfit, Lahnberge, D-3550 Marburg, FRG Offprint requests to." J. R. Andreesen morphology and physiology, strain al-2 did not resemble described amino acid-degrading species. Therefore, the new isolate is proposed as type strain of a new species, Eubacterium acidaminophilum.

- by Jan Andreesen
- •
- Microbiology, Medical Microbiology, Gram Positive, Methyl Viologen

The effects of Glomus intraradices, Pseudomonas alcaligenes and Bacillus pumilus on the root-rot disease complex caused by the root-knot nematode Meloidogyne incognita and the root-rot fungus Macrophomina phaseolina in chickpea was assessed by quantifying differences in the shoot dry mass, pod number, nodulation, and shoot content of chlorophyll, nitrogen, phosphorus and potassium. Inoculation of plants with G. intraradices, P. alcaligenes and B. pumilus alone and in combination significantly increased shoot dry mass, pod number, and content of chlorophyll, nitrogen, phosphorus and potassium in plants inoculated with pathogens over that in the uninoculated control plants. P. alcaligenes caused a greater increase in shoot dry mass, pod number, chlorophyll, nitrogen, phosphorus and potassium in plants with pathogens than did G. intraradices or B. pumilus. Combined application of G. intraradices, P. alcaligenes and B. pumilus to plants inoculated with pathogens caused a greater increase in shoot dry mass, pod number, nitrogen, phosphorus, and potassium than did an application of P. alcaligenes plus B. pumilus or of G. intraradices plus B. pumilus. Root colonization by G. intrardices was high when used alone, while inoculation with the pathogens reduced root colonization by G. intraradices. In the presence of P. alcaligenes and B. pumilus, root colonization by G. intraradices increased. In plants inoculated with just one antagonist, P. alcaligenes reduced galling and nematode multiplication the most, followed by G. intraradices, then B. pumilus. The greatest reduction in galling, nematode multiplication and root-rot was observed when both bacterial species and G. intraradices were applied together.

- by Mohd Sayeed and +1
- •
- Microbiology, Plant Biology, Phosphorus, Bacteria

Lettuce plants, cv. Vera, were grown under five salinity levels in a hydroponical experimental set-up using a 0.15 m deep sand growing bed. A standard nutrient solution was used, with the following composition, in mmol L-1: 16.9 NO3-; 2.0... more

- by Rodrigo Godoi
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- Experimental Design, Plant growth, Lactuca Sativa, HORTICULTURA

The mercury mass fraction has been determined by atomic fluorescence spectrometry (AFS) in the framework of the project "Certification of a reference material (trace elements in fly ash) in replacement of BCR CRM 176". Calculation of the uncertainty budget, as described in this manuscript, emphasizes a practical and realistic approach to estimation of uncertainty components on the basis of statistical assumptions. GUM Workbench software was used, and resulted in a mercury mass fraction of 1.58± 0.11 mg kg -1 (with coverage factor k=2.2, 95% probability) related to dry mass, submitted in the certification exercise. The calculated total uncertainty budget applies to analogous samples analyzed by this procedure.

- by Bart Noten
- •
- Engineering, Data Analysis, Biological Sciences, Uncertainty

RESUMO -Avaliaram-se as características estruturais do capim-tanzânia pastejado por ovinos sob lotação rotativa com quatro níveis de suplementação concentrada (NS) (0,0; 0,6; 1,2 e 1,8% PV), em delineamento de parcelas subdivididas, em que as parcelas foram os níveis de suplementação e os ciclos de pastejo (CP), as subparcelas, com quatro repetições. Estimaram-se as produções de massa seca de forragem total (MSFT), forragem morta (MSFM), forragem verde (MSFV), lâmina foliar verde (MSLV) e colmo verde (MSCV), a altura (ALT) e o número de folhas/perfilho (F/P); as relações folha/colmo (F/C) e material vivo/morto (MV/MM) no pré e pós-pastejo; a densidade populacional de perfilhos (DPP); e o índice de área foliar (IAFres). Não foram observados efeitos dos NS e nem dos ciclos para as variáveis F/P, MSFM, MSFV, MV/MM, MSLV e MSCV. Para a variável ALT, observaram-se diferenças do ciclo 4 em relação aos demais. A MSFT foi afetada pelos NS, de modo que o pasto com ovinos sob suplementação a 0,6% PV foi semelhante aos dos NS de 0,0 e 1,8% PV, porém foi superior ao do NS de 1,2% PV. Foi observado efeito dos NS sobre a MSFTres e MSFMres no nível de 0,6% PV, sendo superior ao do nível de 1,2% PV, porém semelhante aos demais. Para MSFVres observou-se efeito quadrático dos NS, porém não houve efeito dos CP. Para a relação MV/MMres, não foram observadas diferenças entre NS e nem entre CP. Observou-se efeito quadrático dos NS sobre a MSLVres, o IAFres e a MSCVres. Houve aumento linear na F/C com o aumento do NS. Quanto à DPP, não foi observada diferença entre NS. Os níveis crescentes de suplementação não comprometeram o vigor da rebrotação da pastagem, em razão da manutenção dos componentes da biomassa dentro de níveis aceitáveis.

- by Roberto Pompeu
- •
- Research evaluation, Canopy, Population Density, Leaf Area Index

The particulate organic carbon (POC), particulate organic nitrogen (PON), dry mass, and chlorophyll a content of marine snow as a function of individual aggregate size was determined from undisturbed natural aggregates photographed and collected in situ by SCUBA divers at 15 stations off coastal California in order to quantify the matter available in large particles for various ecological processes. POC, PON, and dry mass content were highly significant exponential functions of aggregate volume and were similar for all aggregates regardless of aggregate type, origin, composition or season of collection. POC and PON made up 17-39% and 1.7-6.0%, respectively, of aggregates by weight. C : N ratios increased with increasing aggregate size, suggesting that larger aggregates were older and more refractory than smaller ones. Similarity in the size-specific POC, PON, and mass content of different types of aggregates indicates that the quantities of these materials existing in the larger particle size fractions of the upper ocean could be estimated from profiles of particle size and abundance with depth obtained with in situ camera systems. Such estimates will allow assessment of the availability of marine snow to large particle consumers and decomposers and to sedimentation processes.

- by Alice Alldredge
- •
- Geochemistry, Oceanography, Seasonality, Nitrogen

The influence of light quality on growth and development of in vitro grown Doritaenopsis hort. (Orchidaceae) plants was investigated. Growth parameters like leaf and root fresh/dry mass and leaf area were highest with plants grown under red plus blue light emitting diodes (LEDs). Leaf length was greater with the plants grown under red LED. Carbohydrate (starch, sucrose, glucose and fructose) and leaf pigment (chlorophylls and carotenoids) biosynthesis of the plants was significantly increased in plants grown under red plus blue LEDs compared to red or blue LED and fluorescent light treatments. This study suggests that the production of quality Doritaenopsis plants is possible by culturing the plants in vitro under a mixture of blue plus red light sources.

- by Kee-yoeup Paek
- •
- Plant Biology, Red Light, Growth and development, Blue Light

One of the effects of the dreissenid invasion into the Laurentian Great Lakes appears to be a resurgence in the abundance of the nuisance alga Cladophora glomerata which experienced a marked decline following phosphorus abatement in the late 1970s and early 1980s. A subsidy of bioavailable phosphorus excreted by dreissenid mussels could be an important mechanism facilitating the growth of C. glomerata. To assess the importance of phosphorus released by mussels to C. glomerata growth in the nearshore, we conducted a survey of mussel distribution and abundance followed by in situ experiments designed to measure dreissenid phosphorus excretion rates. Average dreissenid mussel abundance in our study area was 3674 individuals/ m 2 , with an average biomass of 52.2 g of shell free dry mass/m 2 . The mussels excreted bioavailable soluble reactive phosphorus at an average rate of 7.02 μg SRP/g shell free dry mass/hour, contributing about 11 t of soluble reactive phosphorus to our study area over the C. glomerata growing season. Dreissenids appear to be an important source of recycled bioavailable phosphorus to the nearshore, supplying more soluble reactive phosphorus to our study area than local watercourses and WWTPs, and more phosphorus than is required to sustain local C. glomerata growth.

- by Sairah Malkin
- •
- Environmental Engineering, Experience Design, Great Lakes, Phosphorus