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At least 703 records · Page 39Linked to original sources
PubMed1988

Histamine distribution in the gastrointestinal wall of germ free and conventional chicken: evidence of the role of the digestive microflora.

The digestive microflora produces a decrease of the mucosal histamine content in the wall of the chicken colon but has no significant incidence in the upper part of the digestive tract. The anatomical and physiological particularities of the chicken digestive tract permitted to observe that wall histamine concentration depends on different factors. Endogenous factors control the wall histamine content in the proventriculus, independantly of the diet and/or of the presence of a microflora. Diet has a specific incidence upon the gastrointestinal wall of the host in the crop and in the colon. The colon microflora decreases the effect of the diet essentially when the chicken are fed a semi synthetic diet. Interactions between the diet and the microflora could induce physiopathological manifestations.

Animals↗
PubMed2006

Assessing the importance of genotype x environment interaction for root traits in rice using a mapping population. I: a soil-filled box screen.

Altering root system architecture is considered a method of improving crop water and soil nutrient capture. The analysis of quantitative trait loci (QTLs) for root traits has revealed inconsistency in the same population evaluated in different environments. It must be clarified if this is due to genotype x environment interaction or considerations of statistics if the value of QTLs for marker-assisted breeding is to be estimated. A modified split-plot design was used where a main plot corresponded to a separate experiment. The main plot factor had four treatments (environments), which were completely randomized among eight trials, so that each treatment was replicated twice. The sub-plot factor consisted of 168 recombinant inbreed lines of the Bala x Azucena rice mapping population, randomly allocated to the seven soil-filled boxes. The aim of the trial was to quantify QTL x environment interaction. The treatments were chosen to alter partitioning to roots; consisting of a control treatment (high-soil nitrogen, high light and high-water content) and further treatments where light, soil nitrogen or soil water was reduced singly. After 4 weeks growth, maximum root length (MRL), maximum root thickness, root mass below 50 cm, total plant dry mass (%), root mass and shoot length were measured. The treatments affected plant growth as predicted; low nitrogen and drought increased relative root partitioning, low-light decreased it. The parental varieties Bala and Azucena differed significantly for all traits. Broad-sense heritability of most traits was high (57-86%). Variation due to treatment was the most important influence on the variance, while genotype was next. Genotype x environment interaction was detected for all traits except MRL, although the proportion of variation due to this interaction was generally small. It is concluded that genotype x environment interaction is present but less important than genotypic variation. A companion paper presents QTL x environment analysis of data.

Chromosome Mapping↗
PubMed2007

Retransformation of a male sterile barnase line with the barstar gene as an efficient alternative method to identify male sterile-restorer combinations for heterosis breeding.

We report in this study, an improved method for identifying male sterile-restorer combinations using the barnase-barstar system of pollination control for heterosis breeding in crop plants, as an alternative to the conventional line x tester cross method. In this strategy, a transgenic male sterile barnase line was retransformed with appropriate barstar constructs. Double transformants carrying both the barnase and barstar genes were identified and screened for their male fertility status. Using this strategy, 66-90% of fertile retransformants (restored events) were obtained in Brassica juncea using two different barstar constructs. Restored events were analysed for their pollen viability and copy number of the barstar gene. Around 90% of the restored events showed high pollen viability and approximately 30% contained single copy integrations of the barstar gene. These observations were significantly different from those made in our earlier studies using line (barnase) x tester (barstar) crosses, wherein only two viable male sterile-restorer combinations were identified by screening 88 different cross-combinations. The retransformation strategy not only generated several independent restorers for a given male sterile line from a single transformation experiment but also identified potential restorers in the T(0) generation itself leading to significant savings in time, cost and labour. Single copy restored plants with high pollen viability were selfed to segregate male sterile (barnase) and restorer (barstar) lines in the T(1) progeny which could subsequently be diversified into appropriate combiners for heterosis breeding. This strategy will be particularly useful for crop plants where poor transformation frequencies and/or lengthy transformation protocols are a major limitation.

Bacterial Proteins↗
PubMed2006

IWQ index: a GIS-integrated technique to assess irrigation water quality.

The irrigation water quality and the associated hazards to soil characteristics and crop yield is often a complex phenomenon that involves the combined effect of many parameters. From a management point of view, it is sometimes necessary to analyze all related parameters as a combination rather than focusing on a single isolated parameter. With this objective in mind, a new GIS-integrated tool is proposed in this study to evaluate the quality of irrigation waters with regards to potential soil and crop problems. The proposed procedure is mainly an index method that utilizes five hazard groups: (a) salinity hazard, (b) infiltration and permeability hazard, (c) specific ion toxicity, (d) trace element toxicity; and, (e) miscellaneous impacts on sensitive crops. A linear combination of these groups is formulated to form the so-called IWQ index, which is a technique that could be used to classify irrigation waters with respect to three suitability classes. The proposed technique is applied to assess the irrigation water quality of the Simav Plain located in western Anatolia, Turkey. The Simav application is implemented by using a GIS database developed for the plain. Based on the results of this application, the general groundwater quality in the surfacial aquifer is found to be fairly good and the aquifer waters are mostly suitable for irrigation purposes.

Crops, Agricultural↗
PubMed2007

Interaction network of proteins associated with abiotic stress response and development in wheat.

Wheat is the most widely adapted crop to abiotic stresses and considered an excellent system to study stress tolerance in spite of its genetic complexity. Recent studies indicated that several hundred genes are either up- or down-regulated in response to stress treatment. To elucidate the function of some of these genes, an interactome of proteins associated with abiotic stress response and development in wheat was generated using the yeast two-hybrid GAL4 system and specific protein interaction assays. The interactome is comprised of 73 proteins, generating 97 interactions pairs. Twenty-one interactions were confirmed by bimolecular fluorescent complementation in Nicotiana benthamiana. A confidence-scoring system was elaborated to evaluate the significance of the interactions. The main feature of this interactome is that almost all bait proteins along with their interactors were interconnected, creating a spider web-like structure. The interactome revealed also the presence of a "cluster of proteins involved in flowering control" in three- and four-protein interaction loops. This network provides a novel insight into the complex relationships among transcription factors known to play central roles in vernalization, flower initiation and abscisic acid signaling, as well as associations that tie abiotic stress with other regulatory and signaling proteins. This analysis provides useful information in elucidating the molecular mechanism associated with abiotic stress response in plants.

DNA, Complementary↗
PubMed2004

Dithiocarbamates residues in Brazilian food and the potential risk for consumers.

Dithiocarbamates are a non-systemic group of pesticides widely used to protect crops from fungal diseases. The current methodology used by monitoring laboratories to determine dithiocarbamates in food involves the analysis of CS(2) generated after hydrolysis of the compound present in the sample. This method does not identify the origin of the CS(2) detected, which may or may not be related to the presence of pesticides leading to a potential overestimation of the dietary dithiocarbamate intake. In this paper, 520 food samples (papaya, banana, apple, strawberry, orange, potato, tomato, rice and dry beans) collected in the local market of the Federal District, Brazil, were analyzed for dithiocarbamate content. Detectable levels (> or =10.10 mg/kg CS(2)) were found in 60.8% of the samples, with the highest levels (up to 3.8 mg/kg) found in strawberry, papaya and banana. No residues were found in rice (polished) and only one dry bean sample had detectable levels of the fungicides. Detectable residues were found in the pulp of banana, papaya (including the seeds) and orange (50-62% of the analyzed samples). An exposure assessment, based on dithiocarbamate levels detected in the food crops analyzed in this study, confirms that the intake of dithiocarbamates through food consumption in the country does not represent a health risk to consumers, i.e., the estimated daily intake is less than the acceptable daily intake. Furthermore, the implementation of more selective methodologies to individually analyze these compounds in food monitoring programs in Brazil is not necessary.

Brazil↗
PubMed2005

Adsorption of trace elements from poultry litter by montmorillonite clay.

Poultry litter (PL) is used as fertilizer on agricultural lands because of its high nutrient content. However, the litter also contains trace elements such as As, Cd, Cu, Pb, and Zn. On land application of PL, these trace elements may be absorbed by crops, leach into groundwater, or enter the aquatic system as run-off. The objective of this research was to study the effect of the addition of montmorillonite clay-mineral (CM) in reducing the release of trace elements from PL. Cd, Cu, and Zn showed significant decreases of 29, 34, and 22%, respectively, in PL aqueous leachate (compared with the control-PL without CM) on mixing with 0.05 g CM but no change in As, Co, and Cr concentrations was observed. Lead showed a significant increase in PL aqueous leachate on mixing with 0.2 g CM but Pb concentration was two orders of magnitude less than in CM aqueous leachate alone. On washing, the settled precipitate (PL+CM) in the centrifuge tubes with water (desorption study) most of the adsorbed metals (Cd 85%, Cu 61%, and Zn 100%) were released. The results of this study show that the addition of CM resulted in significant adsorption of Cd and Cu from PL.

Adsorption↗
PubMed2002

Nutrient availability and maize growth in a soil amended with earthworm casts from a South African indigenous species.

The study was undertaken to assess the availability to maize of nutrients from earthworm casts (wormcasts) collected from a grazing paddock in the Eastern Cape province of South Africa. Maize (cv PAN 473) was grown in pots filled with ground wormcasts, non-casted surrounding soil and a mixture of the two media. Fertiliser application increased growth and uptake of nutrients by maize grown on both wormcast and non-casted soil. Maize grown on wormcasts had significantly (p < 0.05) higher plant height, stem diameter, dry weight and showed higher nutrient uptake and lower fertiliser response than that grown on corresponding non-casted surface soil. The uptakes of plant nutrients, growth and dry matter yields were in the order fertiliser>wormcasts>non-casted soil. Mixing worm casts with non-casted soil improved maize growth and nutrient uptake over non-casted soil. It is concluded that wormcasts could be used as a soil amendment for crop production, especially in small-scale production systems.

Animals↗
PubMed1997

Purification of aminopeptidase from Australian classified barley flour.

Barley is one of the major crops cultivated in the world. A new milling system, which removes successive layers of the grain has been developed, the preparation being called a classified flour. We have detected aminopeptidase activity in the flour obtained from the near surface zone. Barley was the Weeah species cultivated in Australia. Our aim in this paper is to describe the complete purification of aminopeptidase from barley classified flour. Aminopeptidase activity was determined using L-leucine-p-nitroanilide in 10 mM sodium phosphate buffer, pH 7.0. Aminopeptidase was extracted in 20 mM sodium acetate buffer, pH 5.5. Fractions (HP-1 and HP-2) were obtained upon chromatography using an HI-propyl hydrophobic interaction column in 20 mM acetate buffer, pH 5.5, with a linear gradient of ammonium sulfate from 15 to 0% saturation after the ammonium sulfate fractionation (from 40 to 60% saturation) of the extract. The final purified preparation A-1-I-G was obtained from HP-1 by gel filtration, hydroxylapatite chromatography, diethylaminomethyl-ion exchange chromatography, and re-chromatography on a Sephacryl S-100HR gel column. It was pure as assessed by native and sodium dodecylsulfate-polyacrylamide gel electrophoreses. The specific activity of A-1-I-G was 64.8 fold that of the crude extract. A K(m) value of 0.138 mM when using L-leucine-p-nitroanilide was calculated. A-1-I-G is active over a wide pH range and has a strong affinity for its substrate. The classification process is effective as a step of enzyme purification. Also, the results with metal ions suggest that the enzyme is a metalloenzyme. It was concluded that complete purification of an aminopeptidase from barley was achieved.

Aminopeptidases↗
PubMed2003

The noble radish: past, present and future.

Recent developments in plant biotechnology have revealed that radish can be genetically modified by a technique called "floral-dipping". This system has been used successfully to delay both bolting and flowering in radish by the co-suppression of the photoperiodic gene, GIGANTEA. Future research could use this system to improve the pharmaceutical value of the crop for global usage.

Arabidopsis Proteins↗
PubMed2004

Effect of surface tarp on emissions and distribution of drip-applied fumigants.

Soil fumigants are used to control a wide variety of soil-borne pests in high-cash-value crops. Application of soil fumigants through drip irrigation systems is receiving increasing attention as a method to improve the uniformity of fumigant application. Little information is available on the emissions and soil distribution of fumigants following subsurface drip application, or the effect of plastic tarp on fumigant emissions in these systems. In these experiments, the fumigant compounds 1,3-dichloropropene (1,3-D), Vapam (a methyl isothiocyanate (MITC) precursor), and propargyl bromide (PrBr) were applied to soil beds via drip irrigation at 15 cm depth. Beds were tarped with either standard 1-mil high-density polyethylene (HDPE) or a virtually impermeable film (VIF), leaving the furrows bare. Cumulative emissions of 1,3-D, MITC, and PrBr in these tarped bedded systems was very low, amounting to <10% of the applied mass. These experiments were conducted in the winter months, with average air temperatures of 12-15 degrees C. Cumulative emissions of MITC and 1,3-D from a sandy loam field soil were decreased by > or =80% by tarping the bed with VIF rather than HDPE. A large fraction of the 1,3-D and PrBr flux was from the untarped furrows in VIF-tarped plots, indicating that inhibiting volatilization from the furrow will be important in further reducing emissions in these systems. Monitoring the fumigant distribution in soil indicated that tarping the bed with VIF resulted in a more effective containment of fumigant vapors compared to use of a HDPE tarp.

Air Movements↗
PubMed2006

Transgenic crops expressing Bacillus thuringiensis toxins and biological control.

The area devoted to growing transgenic plants expressing insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) is increasing worldwide. A major concern with the adoption of Bt crops is their potential impact on nontarget organisms including biological control organisms. Regulatory frameworks should advocate a step-wise (tiered) approach to assess possible nontarget effects of Bt crops. Laboratory and glasshouse studies have revealed effects on natural enemies only when Bt-susceptible, sublethally damaged herbivores were used as prey or host, with no indication of direct toxic effects. Field studies have confirmed that the abundance and activity of parasitoids and predators are similar in Bt and non-Bt crops. In contrast, applications of conventional insecticides have usually resulted in negative impacts on biological control organisms. Because Bt-transgenic varieties can lead to substantial reductions in insecticide use in some crops, they can contribute to integrated pest management systems with a strong biological control component.

Bacillus thuringiensis↗
PubMed2006

Growing environment and nutrient availability affect the content of some phenolic compounds in Echinacea purpurea and Echinacea angustifolia.

Medicinal plant production is different from other agricultural production systems in that the plants are grown for the production of specific phytochemical(s) for human use. To address this need, a Good Manufacturing Practice (GMP)-compliant, controlled-environment production system was developed for production of Echinacea purpurea and Echinacea angustifolia. Within the prototype facility, the growing systems, nutrient availability, water and physical environment were highly controlled. The current study was designed to evaluate the effects of different hydroponic systems, nutrient solution NO (3)(-)/NH (4)(+) ratios and mild water stress on the content of some phenolic compounds in Echinacea plants. The deep-flow solution culture system in which the plant roots were continuously immersed in the nutrient solutions was optimum for the growth of E. purpurea. Higher concentrations of caftaric acid, cynarin and echinacoside were produced in E. angustifolia plants grown in the soil-based growing media while the plants grown in the deep-flow solution system had higher levels of cichoric acid. Altering the NO (3)(-)/NH (4)(+) ratio or limited water stress did not have any significant effect on the phytochemical content of Echinacea plants. Echinacea plants grown in the controlled environment systems had higher or similar amounts of cynarin, caftaric acid, echinacoside and cichoric acid as previously reported in the literature for both field-cultivated and wild-harvested Echinacea plants. This growing system offers the advantages of year-round crop production with minimal contamination by environmental pollutants and common microbes.

Echinacea↗
PubMed1999

Case study of the effects of atmospheric aerosols and regional haze on agriculture: an opportunity to enhance crop yields in China through emission controls?

The effect of atmospheric aerosols and regional haze from air pollution on the yields of rice and winter wheat grown in China is assessed. The assessment is based on estimates of aerosol optical depths over China, the effect of these optical depths on the solar irradiance reaching the earth's surface, and the response of rice and winter wheat grown in Nanjing to the change in solar irradiance. Two sets of aerosol optical depths are presented: one based on a coupled, regional climate/air quality model simulation and the other inferred from solar radiation measurements made over a 12-year period at meteorological stations in China. The model-estimated optical depths are significantly smaller than those derived from observations, perhaps because of errors in one or both sets of optical depths or because the data from the meteorological stations has been affected by local pollution. Radiative transfer calculations using the smaller, model-estimated aerosol optical depths indicate that the so-called "direct effect" of regional haze results in an approximately 5-30% reduction in the solar irradiance reaching some of China's most productive agricultural regions. Crop-response model simulations suggest an approximately 1:1 relationship between a percentage increase (decrease) in total surface solar irradiance and a percentage increase (decrease) in the yields of rice and wheat. Collectively, these calculations suggest that regional haze in China is currently depressing optimal yields of approximately 70% of the crops grown in China by at least 5-30%. Reducing the severity of regional haze in China through air pollution control could potentially result in a significant increase in crop yields and help the nation meet its growing food demands in the coming decades.

Agriculture↗
PubMed1975

Sites of organic acid production and pattern of digesta movement in the gastrointestinal tract of geese.

Sixteen geese were used to assess the movement of fluid and particulate digesta through their gastrointestinal tracts and to determine the diurnal variation in organic acid levels for the various segments of the tract. Fluid (polyethylene glycol and chronium-labeled ethylenediaminetetraacetic acid) and particulate markers (2 and 5 mm long) were administered with the meal. Animals were killed at given intervals after the administration of markers. The gastrointestinal tract was divided into nine segments for measurement of markers, pH, volatile fatty acids (VFA), and lactic acid contents. The data indicated a rapid evacuation of fluid marker from the foregut (crop, ventriculus, and proventriculus), while particulate markers were retained for extended periods of time. Retention of fluid marker was observed only within the cecum. Retrograde movement of particulate marker was demonstrated from the duodenum to ventriculus and proventriculus. Retrograde movement of fluid marker was observed from the cloaca to the colon, cecum, and distal third of the small intestine. However, particulate marker showed no retrograde movement in these segments of tract. Highest VFA levels were observed in the cecum. Retention of digesta and production of VFA within the colon were less than those noted for the dog, pig and pony. Lactic acid comprised less than 10% of the organic acids present in the gastrointestinal tract and were at their highest levels in the proximal and mid small intestine.

Animals↗
PubMed2000

UK CropNet: a collection of databases and bioinformatics resources for crop plant genomics.

The UK Crop Plant Bioinformatics Network (UK CropNet) was established in 1996 in order to harness the extensive work in genome mapping in crop plants in the UK. Since this date we have published five databases from our central UK CropNet WWW site (http://synteny.nott.ac.uk/) with a further three to follow shortly. Our resource facilitates the identification and manipulation of agronomically important genes by laying a foundation for comparative analysis among crop plants and model species. In addition, we have developed a number of software tools that facilitate the visualisation and analysis of our data. Many of our tools are made freely available for use with both crop plant data and with data from other species.

Crops, Agricultural↗
PubMed2005

CR-EST: a resource for crop ESTs.

The crop expressed sequence tag database, CR-EST (http://pgrc.ipk-gatersleben.de/cr-est/), is a publicly available online resource providing access to sequence, classification, clustering and annotation data of crop EST projects. CR-EST currently holds more than 200,000 sequences derived from 41 cDNA libraries of four species: barley, wheat, pea and potato. The barley section comprises approximately one-third of all publicly available ESTs. CR-EST deploys an automatic EST preparation pipeline that includes the identification of chimeric clones in order to transparently display the data quality. Sequences are clustered in species-specific projects to currently generate a non-redundant set of approximately 22,600 consensus sequences and approximately 17,200 singletons, which form the basis of the provided set of unigenes. A web application allows the user to compute BLAST alignments of query sequences against the CR-EST database, query data from Gene Ontology and metabolic pathway annotations and query sequence similarities from stored BLAST results. CR-EST also features interactive JAVA-based tools, allowing the visualization of open reading frames and the explorative analysis of Gene Ontology mappings applied to ESTs.

Crops, Agricultural↗