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PubMed2002

Soil arthropods (Coleoptera, Isopoda) in organic and conventional agroecosystems.

The relationship between two soil arthropod communities (Coleoptera and Isopoda) in organic and conventional fields was investigated. Soil arthropods were sampled by pitfall traps, and fuzzy set theory and canonical correspondence analysis (CCA) were used for their classification. The study was conducted in: (1) two organic and two conventional vineyards, (2) two organic and two conventional olive groves, and (3) one organic rotation system that involved maize and one conventional maize field. The species composition (three main fuzzy groups) was affected by the crop species and not by the farming system. The CCA placed the rare and unique taxa of soil arthropods at the edges of the diagram and grouped most of them together in relation to soil organic matter and Ca. The same analysis grouped all olive groves and related them to soil organic matter, all vineyards and related them to soil P and, finally, all maize fields and related them to soil N.

Agriculture↗
PubMed2002

Crop genetic improvement for enhanced human nutrition.

In the past decade, micronutrient malnutrition has been identified as a major underlying cause of numerous human health problems in developing countries. The international agricultural research system has been highly successful in producing crop varieties with traits desired by farmers, such as higher yield and greater tolerance of poor growing conditions. These improved varieties have spread widely throughout developing countries and now provide the staple foods eaten daily by billions of people, including the poor in many difficult to reach rural areas. Modern plant breeding and biotechnology offer new opportunities to use this same international system to increase the micronutrient content and enhance the nutritional value of these staple foods. Over time, this could be an important complement to the progress that is being made in providing micronutrient supplements and fortified foods and in encouraging people to eat more diversified diets. Nutritionists and agriculturists will need to work together to define the deficiencies, target the right populations and deliver the right products.

Crops, Agricultural↗
PubMed2007

A comparison of greenhouse gas emissions from inputs into farm enterprises in southeast Queensland, Australia.

One of the assumptions underlying efforts to convert cropping land, especially marginal crop land, to plantations is that there will be a net reduction in greenhouse gas emissions, with a gas "sink" replacing a high energy system in which the breakdown of biomass is routinely accelerated to prepare for new crops. This research, based on case studies in Kingaroy in southeast Queensland, compares the amount of greenhouse gas (GHGs) emissions from a peanut/maize crop rotation, a pasture system for beef production and a spotted gum (Corymbia citriodora) timber plantation. Three production inputs, fuel, farm machinery and agrochemicals (fertilizer, pesticides and herbicides) are considered. The study extends beyond the farm gate to include packing and transportation and the time period is 30 years. The results suggest that replacing the crops with plantations would indeed reduce emissions but that a pasture system would have even lower net emissions. These findings cast some doubt on the case for farm forestry as a relatively effective means of ameliorating greenhouse gas emissions.

Agriculture↗
PubMed2001

Progression of lymphomatoid papulosis to systemic lymphoma is associated with escape from growth inhibition by transforming growth factor-beta and CD30 ligand.

Our objective is to understand the mechanism of progression of lymphomatoid papulosis (LyP) to CD30+ systemic lymphoma. LyP lesions appear in recurrent crops that regress, only to reappear at a later date in the same or different locations. About 10% of patients develop systemic lymphoma. Because transforming growth factor-beta (TGF-beta) and CD30 ligand inhibit the growth of normal lymphocytes and can be detected in regressing lesions of LyP, we tested the effect of these cytokines on cell lines clonally derived from LyP in the progression to systemic lymphoma. TGF-beta failed to inhibit the growth of lymphoma cells from advanced disease due to mutations of the TGF-beta receptor complex that prevented binding of the ligand to tumor cells. A CD30 ligand agonist antibody caused proliferation of tumor cells from one patient and had no effect on tumor cells of another. In contrast, a Fas agonist antibody caused significant growth inhibition of all cell lines. The results suggest that progression of LyP to lymphoma is associated with escape of lymphoma cells from growth regulation by TGF-beta and CD30 ligand.

Antibodies↗
PubMed2005

A beef herd model for simulating feed intake, animal performance, and manure excretion in farm systems.

A beef herd submodel was created for integration with other farm components to form a whole-farm model capable of simulating a wide range of beef production systems. This herd submodel determined the best available feed or feed mix to meet the fiber, energy, and protein requirements for each of up to six animal groups on the farm. The groups comprised any combination of cows, nursing calves, young heifers, yearling heifers, stockers, and finishing cattle. Protein, energy, and mineral requirements were determined for each group using the Cornell Net Carbohydrate and Protein System, Level 1. Diets were formulated to meet these requirements with available feeds, and the resulting feed intake, growth, and manure DM and nutrient (N, P, and K) excretions were predicted. Required feed characteristics included CP, ruminally degradable protein, acid detergent insoluble protein, NDF, P, and K concentrations. Feed intake was predicted by considering energy intake, potentially limited by fill, and exceeding a minimum roughage requirement. Fill and roughage limits were functions of feed NDF concentrations adjusted to consider particle size distribution and the relative rate of ruminal digestibility or the physical effectiveness of the fiber. The herd submodel was verified to predict feed intakes, nutrient requirements, diets, and manure excretions similar to those recommended or measured for beef animals. Incorporation of the beef herd submodel with other farm components, including crop growth (alfalfa, grass, corn, small grain, and soybean), harvest, storage, feeding, grazing, and manure handling, provided the Integrated Farm System Model. This comprehensive farm-simulation model is a useful research and teaching tool for evaluating and comparing the long-term performance, economics, and environmental impact of beef, dairy, and crop production systems.

Agriculture↗
PubMed1998

Bioregenerative [correction of bioregnerative] life support: not a picnic.

If humans are to live permanently in space, regenerative life support systems are an enabling technology and must replace the picnic approach of taking all supplies required for each mission. These systems are classified by technologies as either physical/chemical or bioregenerative. Both of these system-types can recycle water, remove carbon dioxide, produce oxygen, and recover essential elements from waste products. Bioregenerative can also produce food, thus, making it essential if humans are to exist in space independent of earth. A solely bioregenerative life support system includes plants as a biomass production module and microbial organisms in bioreactors as a resource recovery module. In the Advanced Life Support Program, bioregenerative life support systems are being investigated through a research and technology development project which includes large scale testing as part of the Breadboard Project and human tests conducted in the soon to be constructed BioPlex facility. Research and technology development efforts are directed toward optimizing biomass productivity in controlled chambers by developing light weight, energy efficient, and automated systems; recycling liquid and solid wastes; baselining the operation of bioreactors; determining system microbial stability; assessing chemical contamination; and building models required for long term system operations. The program will include space flight studies in the near future to determine if these life support technologies will function in microgravity. When a bioregenerative system is finally incorporated into a mission, the conversion from a picnic and resupply mentality to permanent recycling and independence from earth will be complete.

Biofilms↗
PubMed2002

A constitutive gene expression system derived from the tCUP cryptic promoter elements.

A limited number of constitutive promoters have been used to direct transgene expression in plants and they are often derived from non-plant sources. Here, we describe novel gene-regulatory elements which are associated with a cryptic constitutive promoter from tobacco, tCUP, and modifications that were made to create a strong gene-expression system that is effective across all living cell types from a wide range of plant species, including several important crops ( Arabidopsis, canola, flax, alfalfa, tobacco). The tCUP 5' untranslated region was mutated to eliminate translational interference by upstream ATGs, and the influence of the Kozak consensus sequence on the levels of a beta-glucuronidase (GUS) reporter gene activity was demonstrated. These modifications resulted in expression that was greatly enhanced in all organs. A TATA consensus sequence was added to the core promoter to complement an existing Initiator (Inr) sequence. Although this addition was known to elevate core promoter activity by 3-fold the additive effect on the overall gene-expression system was marginal in all of the transgenic plants tested. Two transcriptional enhancers were identified and the region containing them were oligomerized, yielding a significant increase in marker gene-expression in some but not all plant species. In general, the enhanced tCUP gene-expression system generated levels of GUS activity which exceeded that of the 35S promoter in most plant species and the elevation in activity occurred uniformly among the various plant organs. The potential benefit of cryptic elements for the construction of gene-expression systems for crop species is discussed

Journal Article↗
PubMed1996

Nematode management in sustainable and subsistence agriculture.

In small-scale, subsistence agriculture in the tropics and the subtropics, traditional farming practices have evolved that provide a sustainable means of reducing the incidence and damage caused by pests including nematodes. Other newer, cultural and low-input practices can also be successfully introduced in small-scale farming. In sustainable and subsistence farming systems, nematodes and some other pests can be managed by integrating different farming practices into four strategies: preventing the introduction and spread of nematodes; using direct, nonchemical, cultural and physical control methods; encouraging naturally occurring biological control agents; and maintaining or enhancing the biodiversity inherent in multiple cropping and multiple cultivar traditional farming systems to increase the available resistance or tolerance to nematodes.

Journal Article↗
PubMed2005

Evaluation of the nitrate content in leaf vegetables produced through different agricultural systems.

The nitrate content of leafy vegetables (watercress, lettuce and arugula) produced by different agricultural systems (conventional, organic and hydroponic) was determined. The daily nitrate intake from the consumption of these crop species by the average Brazilian consumer was also estimated. Sampling was carried out between June 2001 to February 2003 in Campinas, São Paulo State, Brazil. Nitrate was extracted from the samples using the procedure recommended by the AOAC. Flow injection analysis with spectrophotometric detection at 460 nm was used for nitrate determination through the ternary complex FeSCNNO+. For lettuce and arugula, the average nitrate content varied (p < 0.05) between the three agricultural systems with the nitrate level in the crops produced by the organic system being lower than in the conventional system that, in turn, was lower than in the hydroponic system. For watercress, no difference (p < 0.05) was found between the organic and hydroponic samples, both having higher nitrate contents (p < 0.05) than conventionally cultivated samples. The nitrate content for each crop species varied among producers, between different parts of the plant and in relation to the season. The estimated daily nitrate intake, calculated from the consumption of the crops produced by the hydroponic system, represented 29% of the acceptable daily intake established for this ion.

Agriculture↗
PubMed2004

BGI-RIS: an integrated information resource and comparative analysis workbench for rice genomics.

Rice is a major food staple for the world's population and serves as a model species in cereal genome research. The Beijing Genomics Institute (BGI) has long been devoting itself to sequencing, information analysis and biological research of the rice and other crop genomes. In order to facilitate the application of the rice genomic information and to provide a foundation for functional and evolutionary studies of other important cereal crops, we implemented our Rice Information System (BGI-RIS), the most up-to-date integrated information resource as well as a workbench for comparative genomic analysis. In addition to comprehensive data from Oryza sativa L. ssp. indica sequenced by BGI, BGI-RIS also hosts carefully curated genome information from Oryza sativa L. ssp. japonica and EST sequences available from other cereal crops. In this resource, sequence contigs of indica (93-11) have been further assembled into Mbp-sized scaffolds and anchored onto the rice chromosomes referenced to physical/genetic markers, cDNAs and BAC-end sequences. We have annotated the rice genomes for gene content, repetitive elements, gene duplications (tandem and segmental) and single nucleotide polymorphisms between rice subspecies. Designed as a basic platform, BGI-RIS presents the sequenced genomes and related information in systematic and graphical ways for the convenience of in-depth comparative studies (http://rise.genomics.org.cn/).

China↗
PubMed1998

Design and implementation of a vegetarian food system for a closed chamber test.

The National Aeronautics and Space Administration (NASA) is conducting a series of closed chamber environmental tests, called the Lunar Mars Life Support Test Project (LMLSTP), which is designed to provide data for the development of surface habitats for the Moon and Mars. These surface habitats will be closed loop environmental systems that will recycle air and water and will grow crops to provide food for crew members. In conjunction with these tests, the Food Systems Engineering Facility at the Johnson Space Center (JSC) tested a 10-day vegetarian menu based on items that can be made from the projected crop list for these habitats. The planned menu met most of the nutritional requirements of the four crew members and was found highly acceptable. Automation of the food preparation and processing equipment was strongly recommended because the preparation time was judged excessive. The waste generated was largely due to leftovers.

Diet, Vegetarian↗
PubMed1996

The problem of assuring performance robustness of biological life support systems.

A perspective of the process of obtaining performance robustness of space exploration life support systems is presented. Some useful definitions are made, some relevant issues are addressed, and a procedure for establishing performance robustness, so far as it now known, is explained. An example is given to illustrate the procedure.

Air Conditioning↗
PubMed1997

Nutrient recycling systems of Biosphere 2. Litterfall, decomposition, and wastewater recycling: results from the 1991-1993 closure experiment.

Important aspects of nutrient recycling in Biosphere 2 were plant litterfall/leaf decomposition in the terrestrial biomes and sewage and wastewater processing by a constructed wetland system. During the second year of closure, annual litterfall ranged from 1317 +/- 283 g/m2 in the lowland rainforest to 141 +/- 58 g/m2 in the desert sand dune area. Litterfall patterns followed different seasonal regimes in the biomes. Leaf decomposition averaged 90%/year in Biosphere 2, with the smallest leaf loss in the desert biome. For maintenance of soil fertility in the agricultural area, inedible crop material and domestic animal manure was composted, and human waste products and wastewater from people, labs, and domestic animals was processed in a 41-m2 constructed wetland. The wetland produced 1200 kg of fodder and remaining nutrients were returned to the soils via irrigation water.

Biomass↗
PubMed1989

Long-term experiments on man's stay in biological life-support system.

We describe the experimental system having maximal possible closure of material recycling in an ecosystem, including people and plants, which was carried out in a hermetically sealed experimental complex "BIOS-3", 315 m2 in volume. The system included 2 experimentators and 3 phytotrons with plants (total sowing area of 63 m2). Plants were grown with round-the-clock lamp irradiation with 130 Wm-2 PAR intensity. The plants production was food for people. Water exchange of ecosystem, as wall as gas exchange, was fully closed excluding liquids and gas samples taken for chemical analysis outside the system. The total closure of material turnover constituted 91%. Health state of the crew was estimated before, during and after the experiment. A 5-months period did not affect their health. The experiments carried out prove that the closed ecosystem of "man-plants" is a prototype of a life-support system for long-term space expeditions.

Air Conditioning↗
PubMed1994

Porous Tube Plant Nutrient Delivery System development: a device for nutrient delivery in microgravity.

The Porous Tube Plant Nutrient Delivery System or PTPNDS (U.S. Patent #4,926,585) has been under development for the past six years with the goal of providing a means for culturing plants in microgravity, specifically providing water and nutrients to the roots. Direct applications of the PTPNDS include plant space biology investigations on the Space Shuttle and plant research for life support in Space Station Freedom. In the past, we investigated various configurations, the suitability of different porous materials, and the effects of pressure and pore size on plant growth. Current work is focused on characterizing the physical operation of the system, examining the effects of solution aeration, and developing prototype configurations for the Plant Growth Unit (PGU), the flight system for the Shuttle mid-deck. Future developments will involve testing on KC-135 parabolic flights, the design of flight hardware and testing aboard the Space Shuttle.

Capillary Action↗
PubMed1987

A modular BLSS simulation model.

The coordination of material flows in Earth's biosphere is largely made possible by the buffering effect of huge material reservoirs. Without similarly-sized buffers, a bioregenerative life support system (BLSS) for extraterrestrial use will be faced with coordination problems more acute than those in any ecosystem found on earth. A related problem is BLSS design is providing an interface between the various life-support processors, one that will allow for their coordination while still allowing for system expansion. Here we present a modular model of a BLSS that interfaces system processors only with the material storage reservoirs, allowing those reservoirs to act as the principal buffers in the system and thus minimizing difficulties with processor coordination. The modular nature of the model allows independent development of the detailed submodels that exist within the model framework. Using this model, BLSS dynamics were investigated under normal conditions and under various failure modes. Partial and complete failures of various components, such as the waste processor or the plants themselves, drive transient responses in the model system, allowing us to examine the effectiveness of the system reservoirs as buffers. The results from simulations of this sort will help to determine control strategies and BLSS design requirements. An evolved version of this model could be used as an interactive control aid in a future BLSS.

Computer Simulation↗
PubMed2003

Relative effects of the insecticide thiamethoxam on the predator Podisus nigrispinus and the tobacco whitefly Bemisia tabaci in nectaried and nectariless cotton.

The predaceous stinkbug Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) feeds on plants as well as on arthropod prey. The question arises whether feeding on plants might expose the predator to systemic insecticide via ingestion of the active ingredient or its metabolites through plant sap of treated plants. This interaction was investigated with nectaried and nectariless cotton plants cropped in pots and treated with the systemic insecticide thiamethoxam at 0.5, 1.0 and 2.0 mg per plant as a root drench. Development of P. nigrispinus fed on prey and on treated nectaried and nectariless cotton plants and confined at 15, 30 and 45 days after insecticide application, and adult reproduction from nymphs caged 30 days after treatment were determined. Podisus nigrispinus life history traits were unaffected by the type of cotton plant, nectaried or nectariless, but were significantly affected by insecticide dose and time after application. Developmental time was extended and fresh adult body weight was reduced by feeding on prey and treated plants. Nymphs caged on treated plants with the highest thiamethoxam concentration at 15 days after application produced only 13.2% of adults. Females emerged from nymphs caged on both plants and at all thiamethoxam concentrations at day 30 after application presented similar reproductive characteristics, except for age of first oviposition, which was delayed on plants treated with the highest thiamethoxam concentration. Thiamethoxam at 0.5 mg per plant restrained tobacco whitefly, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) colonization only during the first 15 days after application to either cotton plant, and similar immature densities were sampled at day 35 after application on treated and untreated plants. However, plants treated with 1.0 and 2.0 mg per plant as a drench and cropped in pots were protected from tobacco whitefly for up to 45 days after exposure to a whitefly colony.

Animals↗