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At least 271 records · Page 15Linked to original sources
PubMed2006

A case study on algal response to raw and treated effluents from an aluminum plating plant and a pharmaceutical plant.

The algal growth responses to the effluents of an aluminum plating plant and to the wastewater from an analgesic/antiinflammatory-drug-producing pharmaceutical plant were investigated. Growth response of the marine alga Dunaliella tertiolecta was monitored by measuring the two response parameters optical density (OD(640)) and in vitro chlorophyll fluorescence for a period of 14 days. Generally, the two response measurements gave similar results for all effluents but the raw effluents of the aluminum plating plant due to the composition of the wastewater. All wastes affected algal growth either by inhibition only or by stimulation at low concentrations and inhibition at high concentrations. Since pollutant tolerance of algae biased toxicity test results, acclimation of algae to the raw effluent of the aluminum plating plant was examined. Although the water quality parameters of treated effluent of both plants were in the permitted range reported by the Turkish Water Pollution Control Act, they inhibited growth at higher concentrations, implying that the two treatment plants were inefficient. Therefore, the importance of toxicity tests in wastewater discharge regulations was emphasized.

Aluminum↗
PubMed2003

Investigation of organic xenobiotic transfers, partitioning and processing in air-soil-plant systems using a microcosm apparatus. Part II: comparing the fate of chlorobenzenes in grass planted soil.

A microcosm system was used to investigate and compare transfers of 14C labeled-1,2-dichlorobenzene (DCB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB) in an air-soil-plant system using single grass tillers planted into spiked soil. This study was the second phase of a development investigation for eventual study of a range of xenobiotic pollutants. Recoveries from the system were excellent at >90%. The predominant loss pathway for 14C labeled-1,2-DCB and 1,2,4-TCB was volatilisation with 85% and 76% volatilisation of parent compound and volatile metabolites over 5 weeks respectively. Most of the added label in the hexachlorobenzene spiked system remained in soil. Mineralisation was <1% for all compounds. 14C plant burdens expressed as microg parent compound/g plant fresh weight were significant and suggest that plant uptake of chlorobenzenes from soil may be an important exposure pathway for grazing herbivores. Both shoot and root uptake of 14C was detected, with foliar uptake of volatilised compounds dominating shoot uptake, and being greatest in TCB spiked systems. The microcosm is shown as potentially an ideal system with which to investigate organic xenobiotic partitioning in air-soil-plant systems to improve understanding of the equilibria and kinetics of exchanges. However, limitations imposed by the lab based conditions must be recognized and data should be compared with field based data sets as a consequence.

Carbon Radioisotopes↗
PubMed2000

Development of a plant growth unit for growing plants over a long-term life cycle under microgravity conditions.

To study the effect of the space environment on plant growth including the reproductive growth and genetic aberration for a long-term plant life cycle, we have initiated development of a new type of facility for growing plants under microgravity conditions. The facility is constructed with subsystems for controlling environmental elements. In this paper, the concept of the facility design is outlined. Subsystems controlling air temperature, humidity, CO2 concentration, light and air circulation around plants and delivering recycled water and nutrients to roots are the major concerns. Plant experiments for developing the facility and future plant experiments with the completed facility are also overviewed. We intend to install this facility in the Japan Experiment Facility (JEM) boarded on the International Space Station.

Air Conditioning↗
PubMed2002

The role of glycine betaine in the protection of plants from stress: clues from transgenic plants.

The acclimation of a plant to a constantly changing environment involves the accumulation of certain organic compounds of low molecular mass, known collectively as compatible solutes, in the cytoplasm. The evidence from numerous investigations of the physiology, genetics, biophysics and biochemistry of plants strongly suggests that glycine betaine (GB), an amphoteric quaternary amine, plays an important role as a compatible solute in plants under various types of environmental stress, such as high levels of salts and low temperature. Plant species vary in their capacity to synthesize GB and some plants, such as spinach and barley, accumulate relatively high levels of GB in their chloroplasts while others, such as Arabidopsis and tobacco, do not synthesize this compound. Genetic engineering has allowed the introduction into GB-deficient species of biosynthetic pathways to GB from both micro-organisms and higher plants; this approach has facilitated investigations of the importance of GB in stress protection. In this review, we summarize recent progress in the genetic manipulation of the synthesis of GB, with special emphasis on the relationship between the protective effects of GB in vivo and those documented in vitro.

Journal Article↗
PubMed2001

Engineering salt-tolerant Brassica plants: characterization of yield and seed oil quality in transgenic plants with increased vacuolar sodium accumulation.

Transgenic Brassica napus plants overexpressing AtNHX1, a vacuolar Na(+)/H(+) antiport from Arabidopsis thaliana, were able to grow, flower, and produce seeds in the presence of 200 mM sodium chloride. Although the transgenic plants grown in high salinity accumulated sodium up to 6% of their dry weight, growth of the these plants was only marginally affected by the high salt concentration. Moreover, seed yields and the seed oil quality were not affected by the high salinity of the soil. Our results demonstrate the potential use of these transgenic plants for agricultural use in saline soils. Our findings, showing that the modification of a single trait significantly improved the salinity tolerance of this crop plant, suggest that with a combination of breeding and transgenic plants it could be possible to produce salt-tolerant crops with far fewer target traits than had been anticipated.

Journal Article↗
PubMed1995

Broad resistance to plant viruses in transgenic plants conferred by antisense inhibition of a host gene essential in S-adenosylmethionine-dependent transmethylation reactions.

S-Adenosylhomocysteine hydrolase (SAHH) is a key enzyme in transmethylation reactions that use S-adenosylmethionine as the methyl donor. Because of the importance of SAHH in a number of S-adenosylmethionine-dependent transmethylation reactions, particularly the 5' capping of mRNA during viral replication, SAHH has been considered as a target of potential antiviral agents against animal viruses. To test the possibility of engineering a broad type of resistance to plant viruses, we expressed the antisense RNA for tobacco SAHH in transgenic tobacco plants. As expected, transgenic plants constitutively expressing an anti-sense SAHH gene showed resistance to infection by various plant viruses. Among those plants, about half exhibited some level of morphological change (typically stunting). Analysis of the physiological change in those plants showed that they contained excess levels of cytokinin. Because cytokinin has been found to induce acquired resistance, there is also a strong possibility that the observed resistance was induced by cytokinin.

Journal Article↗
PubMed2006

Atomic structure of plant glutamine synthetase: a key enzyme for plant productivity.

Plants provide nourishment for animals and other heterotrophs as the sole primary producer in the food chain. Glutamine synthetase (GS), one of the essential enzymes for plant autotrophy catalyzes the incorporation of ammonia into glutamate to generate glutamine with concomitant hydrolysis of ATP, and plays a crucial role in the assimilation and re-assimilation of ammonia derived from a wide variety of metabolic processes during plant growth and development. Elucidation of the atomic structure of higher plant GS is important to understand its detailed reaction mechanism and to obtain further insight into plant productivity and agronomical utility. Here we report the first crystal structures of maize (Zea mays L.) GS. The structure reveals a unique decameric structure that differs significantly from the bacterial GS structure. Higher plants have several isoenzymes of GS differing in heat stability and catalytic properties for efficient responses to variation in the environment and nutrition. A key residue responsible for the heat stability was found to be Ile-161 in GS1a. The three structures in complex with substrate analogues, including phosphinothricin, a widely used herbicide, lead us to propose a mechanism for the transfer of phosphate from ATP to glutamate and to interpret the inhibitory action of phosphinothricin as a guide for the development of new potential herbicides.

Adenosine Triphosphate↗
PubMed1977

Toxicants in plants and plant products.

Toxicants are widely distributed in plants and plant products, including intentionally added, incidentally added, and naturally occurring food toxicants. This review covers the toxicity of some food additives: the distribution, residues, toxicity, and methods of removal of some pesticides and toxic metals; and the presence of naturally occurring toxicants in plants and plant products. Extensive review has been done, particularly on natural toxicants. However, there are still extensive gaps in our knowledge pertaining to effect upon the health of many of the substances known to be present in natural plant food products, as well as even the identity of many natural chemical components of plant foods and their potential toxicological significance. An understanding of their presence, formation, and toxicity is important as far as public health is concerned.

Enzyme Inhibitors↗
PubMed2004

Plant-insect interactions: double-dating associated insect and plant lineages reveals asynchronous radiations.

An increasing number of plant-insect studies using phylogenetic analysis suggest that cospeciation events are rare in plant-insect systems. Instead, nonrandom patterns of phylogenetic congruence are produced by phylogenetically conserved host switching (to related plants) or tracking of particular resources or traits (e.g., chemical). The dominance of host switching in many phytophagous insect groups may make the detection of genuine cospeciation events difficult. One important test of putative cospeciation events is to verify whether reciprocal speciation is temporally plausible. We explored techniques for double-dating of both plant and insect phylogenies. We use dated molecular phylogenies of a psyllid (Hemiptera)-Genisteae (Fabaceae) system, a predominantly monophagous insect-plant association widespread on the Atlantic Macaronesian islands. Phylogenetic reconciliation analysis suggests high levels of parallel cladogenesis between legumes and psyllids. However, dating using molecular clocks calibrated on known geological ages of the Macaronesian islands revealed that the legume and psyllid radiations were not contemporaneous but sequential. Whereas the main plant radiation occurred some 8 million years ago, the insect radiation occurred about 3 million years ago. We estimated that >60% of the psyllid speciation has resulted from host switching between related hosts. The only evidence for true cospeciation is in the much more recent and localized radiation of genistoid legumes in the Canary Islands, where the psyllid and legume radiations have been partially contemporaneous. The identification of specific cospeciation events over this time period, however, is hindered by the phylogenetic uncertainty in both legume and psyllid phylogenies due to the apparent rapidity of the species radiations.

Animals↗
PubMed2004

Comparative analysis of plant and animal calcium signal transduction element using plant full-length cDNA data.

We obtained 32K full-length cDNA sequence data from the rice full-length cDNA project and performed a homology search against NCBI GenBank data. We have also searched homologs of Arabidopsis and other plants' genes with the databases. Comparative analysis of calcium ion transport proteins revealed that the genes specific for muscle and nerve calcium signal transduction systems (VDCC, IP3 receptor, ryanodine receptor) are very different in animals and plants. In contrast, Ca elements with basic functions in cell responses (CNGC, iGlu receptor, Ca(2+)ATPase, Ca2+/Na(+)-K+ ion exchanger) are basically conserved between plants and animals. We also performed comparative analyses of calcium ion binding and/or controlling signal transduction proteins. Many genes specific for muscle and nerve tissue do not exist in plants. However, calcium ion signal transduction genes of basic functions of cell homeostasis and responses were well conserved; plants have developed a calcium ion interacting system that is more direct than in animals. Many species of plants have specifically modified calcium ion binding proteins (CPK, CRK), Ca2+/phospholipid-binding domains, and calcium storage proteins.

Animals↗
PubMed1976

Photorespiration in c(3) and c(4) plant tissue cultures: significance of kranz anatomy to low photorespiration in c(4) plants.

Photorespiration rates in tissue cultures of a C(4) plant, Portulaca oleracea, were compared to those in tissue cultures of a C(3) plant, Streptanthus tortuosus. The C(4) plant tissue cultures have one-half to one-third the photorespiration rate of the C(3) plant tissue cultures and respond to varying O(2) concentrations in a manner typical of C(4) plants. The results suggest that the lack of detectable photorespiration in C(4) plants is not related to leaf anatomy.

Journal Article↗
PubMed1989

Host-Pathogen Interactions : XXXIII. A Plant Protein Converts a Fungal Pathogenesis Factor into an Elicitor of Plant Defense Responses.

This paper describes the effect of a plant-derived polygalacturonase-inhibiting protein (PGIP) on the activity of endopolygalacturonases isolated from fungi. PGIP's effect on endopolygalacturonases is to enhance the production of oligogalacturonides that are active as elicitors of phytoalexin (antibiotic) accumulation and other defense reactions in plants. Only oligogalacturonides with a degree of polymerization higher than nine are able to elicit phytoalexin synthesis in soybean cotyledons. In the absence of PGIP, a 1-minute exposure of polygalacturonic acid to endopolygalacturonase resulted in the production of elicitor-active oligogalacturonides. However, the enzyme depolymerized essentially all of the polygalacturonic acid substrate to elicitor-inactive oligogalacturonides within 15 minutes. When the digestion of polygalacturonic acid was carried out with the same amount of enzyme but in the presence of excess PGIP, the rate of production of elicitor-active oligogalacturonides was dramatically altered. The amount of elicitor-active oligogalacturonide steadily increased for 24 hours. It was only after about 48 hours that the enzyme converted the polygalacturonic acid into short, elicitor-inactive oligomers. PGIP is a specific, reversible, saturable, high-affinity receptor for endopolygalacturonase. Formation of the PGIP-endopolygalacturonase complex results in increased concentrations of oligogalacturonides that activate plant defense responses. The interaction of the plant-derived PGIP with fungal endopolygalacturonases may be a mechanism by which plants convert endopolygalacturonase, a factor important for the virulence of pathogens, into a factor that elicits plant defense mechanisms.

Journal Article↗
PubMed2002

Resistance and tolerance in a host plant-holoparasitic plant interaction: genetic variation and costs.

Host organisms are believed to evolve defense mechanisms (i.e., resistance and/or tolerance) under selective pressures exerted by natural enemies. A prerequisite for the evolution of resistance and tolerance is the existence of genetic variation in these traits for natural selection to act. However, selection for resistance and/or tolerance may be constrained by negative genetic correlations with other traits that affect host fitness. We studied genetic variation in resistance and tolerance against parasitic infection and the potential fitness costs associated with these traits using a novel study system, namely the interaction between a flowering plant and a parasitic plant. In this system, parasitic infection has significant negative effects on host growth and reproduction and may thus act as a selective agent. We conducted a greenhouse experiment in which we grew host plants, Urtica dioica, that originated from a single natural population and represented 20 maternal families either uninfected or infected with the holoparasitic dodder, Cuscuta europaea. that originated from the same site. We calculated correlations among resistance, tolerance, and host performance to test for costs of resistance and tolerance. We measured resistance as parasite performance (quantitative resistance) and tolerance as the slopes of regressions relating the vegetative and reproductive biomass of host plants to damage level (measured as parasite biomass). We observed significant differences among host families in parasite resistance and in parasite tolerance in terms of reproductive biomass, a result that suggests genetic variation in these traits. Furthermore, we found differences in resistance and tolerance between female and male host plants. In addition, the correlations indicate costs of resistance in terms of host growth and reproduction and costs of tolerance in terms of host reproduction. Our results thus indicate that host tolerance and resistance can evolve as a response to infection by a parasitic plant and that costs of resistance and tolerance may be one factor maintaining genetic variation in these traits.

Analysis of Variance↗
PubMed2000

Use of the T-RFLP technique to assess spatial and temporal changes in the bacterial community structure within an agricultural soil planted with transgenic and non-transgenic potato plants.

The aim of this study was to examine whether the terminal restriction fragment length polymorphism (T-RFLP) analysis represents an appropriate technique for monitoring highly diverse soil bacterial communities, i.e. to assess spatial and/or temporal effects on bacterial community structure. The T-RFLP method, a recently described fingerprinting technique, is based on terminal restriction fragment length polymorphisms between distinct small-subunit rRNA gene sequence types. This technique permits an automated quantification of the fluorescence signal intensities of the individual terminal restriction fragments (T-RFs) in a given community fingerprint pattern. The indigenous bacterial communities of three soil plots located within an agricultural field of 110 m(2) were compared. The first site was planted with non-transgenic potato plants, while the other two were planted with transgenic GUS and Barnase/Barstar potato plants, respectively. Once prior to planting and three times after planting, seven parallel samples were taken from each of the three soil plots. The T-RFLP analysis resulted in very complex but highly reproducible community fingerprint patterns. The percentage abundance values of defined T-RFs were calculated for the seven parallel samples of the respective soil plot. A multivariate analysis of variance was used to test T-RFLP data sets for significant differences. The statistical treatments clearly revealed spatial and temporal effects, as well as spacextime interaction effects, on the structural composition of the bacterial communities. T-RFs which showed the highest correlations to the discriminant factors were not those T-RFs which showed the largest single variations between the seven-sample means of individual plots. In summary, the T-RFLP technique, although a polymerase chain reaction-based method, proved to be a suitable technique for monitoring highly diverse soil microbial communities for changes over space and/or time.

Journal Article↗
PubMed2005

Plant Methods: putting the spotlight on technological innovation in the plant sciences.

Plant Methods is a new journal for plant biologists, specialising in the rapid publication of peer-reviewed articles with a focus on technological innovation in the plant sciences. The aim of Plant Methods is to stimulate the development and adoption of new and improved techniques and research tools in plant biology. We hope to promote more consistent standards in the plant sciences, and make readily accessible laboratory and computer-based research tools available to the whole community. This will be achieved by publishing Research articles, Methodology papers and Reviews using the BioMed Central Open Access publishing model. The journal is supported by a prestigious editorial board, whose members all recognise the importance of technological innovation as a driver for basic science.

Editorial↗
PubMed2000

[Presence of plant sterols in the diet and the hypocholesterolemic effects of plant sterols].

BACKGROUND: A high intake of fat, and in particular saturated fat, is associated with an increased risk of coronary heart disease. Reduced intake of spreads had therefore generally been recommended. A special type of "heart-friendly" margarine, a plant sterol enriched margarine, has been a commercial success since it was introduced in 1995. Such margarine may be defined as a functional food, and is not available in Norway. The aim of this article is to give an overview of plant sterols and their distribution in different foods as well as of their hypocholesterolaemic effects. MATERIAL AND METHODS: The Medline database was used to identify relevant literature. RESULTS: An intake of 2-3 grams of plant sterols/day is associated with a 10% reduction of total cholesterol and a 13-15% reduction of LDL cholesterol, whereas HDL cholesterol remains largely unchanged. This amount of plant sterols may be incorporated into approximately 20 grams of margarine. Subjects that are poor responders to treatment with statins may benefit from such margarine, and also children with familial hypercholesterolaemia. Such margarine may have a potential in addition to dietary treatment, as an additional hypocholesterolaemic effect is observed in subjects who already have a healthy diet. INTERPRETATION: A daily intake of approximately 20 grams of plant sterol enriched margarine is associated with significant reductions of both total and LDL cholesterol. However, use of plant sterol enriched margarine can not replace the overall beneficial effects of a well balanced heart-friendly diet.

Anticholesteremic Agents↗
PubMed1984

Plant-plant interactions.

Higher plants show three types of biochemical adaptation which enable them to combat pathogenic organisms in the form of lower plants. Firstly they may synthesize antibacterial or antifungal compounds in concentrations that prevent the invasion of the higher plant by the bacteria or fungi. Secondly they may synthesize such compounds in less than adequate amounts for defence in healthy tissues but respond to invasion by increasing the synthesis; and, thirdly, they may respond to invasion by synthesizing antibacterial or antifungal compounds de novo. Higher plants also show biochemical adaptations that enable them to compete with individuals of the same or different higher plant species. These include the synthesis of volatile and water-soluble phytotoxins which suppress the germination, growth, or both, of competitors.

Adaptation, Biological↗
PubMed2006

Comparing a selenium accumulator plant (Brassica juncea) to a nonaccumulator plant (Helianthus annuus) to investigate selenium-containing proteins.

Selenoproteins have been identified in a diverse range of organisms, including bacteria and animals. Their occurrence and role in the plant kingdom are, however, less well-understood. This work investigated the water-soluble selenium-containing proteins extracted from a selenium-accumulating plant species (Brassica juncea) and a nonaccumulator species (Helianthus annuus) exposed to varying forms and concentrations of selenium. Firstly, protein extracts were analyzed by size exclusion chromatography coupled to inductively coupled plasma mass spectrometry; specific detection was achieved by monitoring characteristic isotopes. Then, proteolytic digests of the plant extracts were analyzed by reversed phase chromatography coupled to ICP-MS in order to investigate selenoamino acid and selenopeptide content. Selenomethionine was observed to be the primary constituent of the proteins of the nonaccumulator plant, while selenocystine and selenomethionine were found in the same proportion in the accumulator extract. One main selenium-containing species was present at higher levels in the root digests than in the leaf digests; levels were greater in the nonaccumulator than in the accumulator plant.

Chromatography, High Pressure Liquid↗