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Score: 19.00
Title: Safety and nutritional assessment of GM plants and derived food and feed : the role of animal feeding trials .
Citation: V : 46 Suppl 1 P : S2-70 Year: 2008 Type: MEDLINE
Literature: oryza Field: abstract Doc ID: pub18328408
Abstract: In this report the various elements of the safety and nutritional assessment procedure for genetically modified ( GM ) plant derived food and feed are discussed , in particular the potential and limitations of animal feeding trials for the safety and nutritional testing of whole GM food and feed . The general principles for the risk assessment of GM plants and derived food and feed are followed , as described in the EFSA guidance document of the EFSA Scientific Panel on Genetically Modified Organisms . In Section 1 the mandate , scope and general principles for risk assessment of GM plant derived food and feed are discussed . Products under consideration are food and feed derived from GM plants , such as maize , soybeans , oilseed rape and cotton , modified through the introduction of one or more genes coding for agronomic input traits like herbicide tolerance and/or insect resistance . Furthermore GM plant derived food and feed , which have been obtained through extensive genetic modifications targeted at specific alterations of metabolic pathways leading to improved nutritional and/or health characteristics , such as rice containing beta-carotene , soybeans with enhanced oleic acid content , or tomato with increased concentration of flavonoids , are considered . The safety assessment of GM plants and derived food and feed follows a comparative approach , ie the food and feed are compared with their non-GM counterparts in order to identify intended and unintended ( unexpected ) differences which subsequently are assessed with respect to their potential impact on the environment , safety for humans and animals , and nutritional quality . Key elements of the assessment procedure are the molecular , compositional , phenotypic and agronomic analysis in order to identify similarities and differences between the GM plant and its near isogenic counterpart . The safety assessment is focussed on ( i ) the presence and characteristics of newly expressed proteins and other new constituents and possible changes in the level of natural constituents beyond normal variation , and on the characteristics of the GM food and feed , and ( ii ) the possible occurrence of unintended ( unexpected ) effects in GM plants due to genetic modification . In order to identify these effects a comparative phenotypic and molecular analysis of the GM plant and its near isogenic counterpart is carried out , in parallel with a targeted analysis of single specific compounds , which represent important metabolic pathways in the plant like macro and micro nutrients , known anti-nutrients and toxins . Significant differences may be indicative of the occurrence of unintended effects , which require further investigation . Section 2 provides an overview of studies performed for the safety and nutritional assessment of whole food and feed . Extensive experience has been built up in recent decades from the safety and nutritional testing in animals of irradiated foods , novel foods and fruit and vegetables . These approaches are also relevant for the safety and nutritional testing of whole GM food and feed . Many feeding trials have been reported in which GM foods like maize , potatoes , rice , soybeans and tomatoes have been fed to rats or mice for prolonged periods , and parameters such as body weight , feed consumption , blood chemistry , organ weights , histopathology etc have been measured . The food and feed under investigation were derived from GM plants with improved agronomic characteristics like herbicide tolerance and/or insect resistance . The majority of these experiments did not indicate clinical effects or histopathological abnormalities in organs or it issues of exposed animals . In some cases adverse effects were noted , which were difficult to interpret due to shortcomings in the studies . Many studies have also been carried out with feed derived from GM plants with agronomic input traits in target animal species to assess the nutritive value of the feed and their performance potential Studies in sheep , pigs , broilers , lactating dairy cows , and fish , comparing the in vivo bioavailability of nutrients from a range of GM plants with their near isogenic counterpart and commercial varieties , showed that they were comparable with those for near isogenic non-GM lines and commercial varieties . In Section 3 toxicological in vivo , in silico , and in vitro test methods are discussed which may be applied for the safety and nutritional assessment of specific compounds present in food and feed or of whole food and feed derived from GM plants . Moreover the purpose , potential and limitations of the 90-day rodent feeding trial for the safety and nutritional testing of whole food and feed have been examined . Methods for single and repeated dose toxicity testing , reproductive and developmental toxicity testing and immunotoxicity testing , as described in OECD guideline tests for single well-defined chemicals are discussed and considered to be adequate for the safety testing of single substances including new products in GM food and feed . Various in silico and in vitro methods may contribute to the safety assessment of GM plant derived food and feed and components thereof , like ( i ) in silico searches for sequence homology and/or structural similarity of novel proteins or their degradation products to known toxic or allergenic proteins , ( ii ) simulated gastric and intestinal fluids in order to study the digestive stability of newly expressed proteins and in vitro systems for analysis of the stability of the novel protein under heat or other processing conditions , and ( iii ) in vitro genotoxicity test methods that screen for point mutations , chromosomal aberrations and DNA damage/repair . The current performance of the safety assessment of whole foods is mainly based on the protocols for low-molecular-weight chemicals such as pharmaceuticals , industrial chemicals , pesticides , food additives and contaminants . However without adaptation , these protocols have limitations for testing of whole food and feed . This primarily results from the fact that defined single substances can be dosed to laboratory animals at very large multiples of the expected human exposure , thus giving a large margin of safety . In contrast foodstuffs are bulky , lead to satiation and can only be included in the diet at much lower multiples of expected human intakes . When testing whole foods , the possible highest concentration of the GM food and feed in the laboratory animal diet may be limited because of nutritional imbalance of the diet , or by the presence of compounds with a known toxicological profile . The aim of the 90-days rodent feeding study with the whole GM food and feed is to assess potential unintended effects of toxicological and/or nutritional relevance and to establish whether the GM food and feed is as safe and nutritious as its traditional comparator rather than determining qualitative and quantitative intrinsic toxicity of defined food constituents . The design of the study should be adapted from the OECD 90-day rodent toxicity study . The precise study design has to take into account the nature of the food and feed and the characteristics of the new trait ( s ) and their intended role in the GM food and feed . A 90-day animal feeding trial has a large capacity ( sensitivity and specificity ) to detect potential toxicological effects of single well defined compounds . This can be concluded from data reported on the toxicology of a wide range of industrial chemicals , pharmaceuticals , food substances , environmental , and agricultural chemicals . It is possible to model the sensitivity of the rat subchronic feeding study for the detection of hypothetically increased amount of compounds such as anti-nutrients , toxicants or secondary metabolites . With respect to the detection of potential unintended effects in whole GM food and feed , it is unlikely that substances present in small amounts and with a low toxic potential will result in any observable ( unintended ) effects in a 90-day rodent feeding study , as they would be below the no-observed-effect-level and thus of unlikely impact to human health at normal intake levels . Laboratory animal feeding studies of 90-days duration appear to be sufficient to pick up adverse effects of diverse compounds that would also give adverse effects after chronic exposure . This conclusion is based on literature data from studies investigating whether toxicological effects are adequately identified in 3-month subchronic studies in rodents , by comparing findings at 3 and 24 months for a range of different chemicals . The 90-day rodent feeding study is not designed to detect effects on reproduction or development other than effects on adult reproductive organ weights and histopathology . Analyses of available data indicate that , for a wide range of substances , reproductive and developmental effects are not potentially more sensitive endpoints than those examined in subchronic toxicity tests . Should there be structural alerts for reproductive/developmental effects or other indications from data available on a GM food and feed , then these tests should be considered . By relating the estimated daily intake , or theoretical maximum daily intake per capita for a given whole food ( or the sum of its individual commercial constituents ) to that consumed on average per rat per day in the subchronic 90-day feeding study , it is possible to establish the margin of exposure ( safety margin ) for consumers . Results obtained from testing GM food and feed in rodents indicate that large ( at least 100-fold ) safety margins exist between animal exposure levels without observed adverse effects and estimated human daily intake . Results of feeding studies with feed derived from GM plants with improved agronomic properties , carried out in a wide range of livestock species , are discussed . The studies did not show any biologically relevant differences in the parameters tested between control and test animals . ( ABSTRACT TRUNCATED )
Score: 18.00
Title: Dynamic analysis of QTLs on tiller number in rice ( Oryza sativa L ) with single segment substitution lines .
Author: Liu G Zhu H Zhang G Li L Ye G
Citation: V : 125 P : 143-53 Year: 2012 Type: In-Process
Literature: oryza Field: abstract Doc ID: pub22350178
Abstract: Twelve single segment substitution lines ( SSSLs ) in rice , which contain quantitative trait loci ( QTLs ) for tiller number detected previously , were used to study dynamic expression of the QTLs in this study . These SSSLs and their recipient , Hua-Jing-Xian 74 ( HJX74 ) , were used to produce 78 crossing combinations first , and then these combinations and their parents were grown in two planting seasons with three cropping densities . Tiller number was measured at seven developmental stages . QTL effects including main effects ( additive , dominance and epistasis ) , QTL x season and QTL x density interaction effects were analyzed at each measured stage . The additive , dominant and epistatic effects of the 12 QTLs as well as their interaction effects with the seasons and with the densities all display dynamic changes with the development . Eight QTLs are detected with significant additive effects and/or additive x season and/or additive x density interaction effects at least at one developmental stage , and all QTLs have significant dominant and epistatic effects and/or interaction effects involved in . For most of the QTLs dominant effects are much bigger than additive effects , showing overdominance . Each QTL interacts at least with eight other QTLs . Additive and dominant effects of these QTLs are mostly positive while epistatic effects are negative and minor . Most of the QTLs show significant interactions with planting seasons and cropping densities , but the additive effects of QTLs Tn3-1 and Tn3-2 , the dominant effects of QTL Tn7 and Tn8 , and the epistatic effects of 14 pairs of QTLs are stable across seasons and the dominant effect of QTL Tn3-3 and the epistatic effects of QTL pairs Tn2-1/Tn6-2 , Tn2-1/Tn9 and Tn3-3/Tn6-3 are nearly consistent across cropping densities . This paper is the first report of dynamics on dominances and epistasis of QTLs for tiller number in rice and provides abundant information , which is useful to improve rice tiller number via heterosis and/or QTL pyramiding .
Score: 15.00
Title: Detection and characterization of glutathione S-transferase activity in rice EF-1betabetagamma and EF-1gamma expressed in Escherichia coli .
Author: Kobayashi S Kidou S Ejiri S
Citation: V : 288 ( 3 ) P : 509-14 Year: 2001 Type: ARTICLE
Literature: oryza Field: abstract Doc ID: pub11676472
Abstract: Plant elongation factor EF-1 consists of four subunits ( EF-1alphabetabetagamma ) . EF-1alpha . GTP catalyses the binding of aminoacyl-tRNA to the ribosome . EF-1beta and EF-1beta catalyze the GDP/GTP exchange on EF-1alpha . GDP . However , the function of EF-1gamma , a subunit detected in eukaryotes , but not in prokaryotes remained unknown . This report demonstrates that rice EF-1betabetagamma and recombinant EF-1gamma possess glutathione S-transferase ( GST ) activity . The EF-1betabetagamma or EF-1gamma-dependent GST activity is about one-fiftieth of the rice GST activity . The Km values of EF-1betabetagamma , EF-1gamma , and rice GST for glutathione and 1-chloro-2 , 4-dinitrobenzene are of about the same order . Although recombinant EF-1gamma is heat labile , active EF-1gamma was obtained by purifying it in the presence of 20% glycerol .
Score: 15.00
Title: Particulate emission factors for mobile fossil fuel and biomass combustion sources .
Author: Watson JG Chow JC Chen LW Lowenthal DH Fujita EM Kuhns HD Sodeman DA Campbell DE Moosmuller H Zhu D Motallebi N
Citation: V : 409 P : 2384-96 Year: 2011 Type: MEDLINE
Literature: oryza Field: abstract Doc ID: pub21458027
Abstract: PM emission factors ( EFs ) for gasoline and diesel-fueled vehicles and biomass combustion were measured in several recent studies . In the Gas/Diesel Split Study ( GD-Split ) , PM ( 2 . 5 ) EFs for heavy-duty diesel vehicles ( HDDV ) ranged from 0 . 2 to 2 g/mile and increased with vehicle age . EFs for HDDV estimated with the US EPA MOBILE 6 . 2 and California Air Resources Board ( ARB ) EMFAC2007 models correlated well with measured values . PM ( 2 . 5 ) EFs measured for gasoline vehicles were two orders of magnitude lower than those for HDDV and did not correlate with model estimates . In the Kansas City Study , PM ( 2 . 5 ) EFs for gasoline-powered vehicles ( eg , passenger cars and light trucks ) were generally <0 . 03 g/mile and were higher in winter than summer . EMFAC2007 reported higher PM ( 2 . 5 ) EFs than MOBILE 6 . 2 during winter , but not during summer , and neither model captured the variability of the measured EFs . Total PM EFs for heavy-duty diesel military vehicles ranged from 0 . 18+/-0 . 03 and 1 . 20+/-0 . 12 g/kg fuel , corresponding to 0 . 3 and 2 g/mile , respectively . These values are comparable to those of on-road HDDV . EFs for biomass burning measured during the Fire Laboratory at Missoula Experiment ( FLAME ) were compared with EFs from the ARB Emission Estimation System ( EES ) model . The highest PM ( 2 . 5 ) EFs ( 76 . 8+/-37 . 5 g/kg ) were measured for wet ( >50% moisture content ) Ponderosa Pine needles . EFs were generally <20 g/kg when moisture content was <20% . The EES model agreed with measured EFs for fuels with low moisture content but underestimated measured EFs for fuel with moisture content >40% . Average EFs for dry chamise , rice straw , and dry grass were within a factor of three of values adopted by ARB in Californias San Joaquin Valley ( SJV ) . Discrepancies between measured and modeled emission factors suggest that there may be important uncertainties in current PM ( 2 . 5 ) emission inventories .
Score: 13.00
Title: [ Genetic effects of mineral elements of Fe , Zn , Mn and P in black pericarp rice grains ]
Author: Zhang MW Du YQ Peng ZM He CX .
Citation: V : 27 ( 9 ) P : 792-9 Year: Type: ARTICLE
Literature: oryza Field: abstract Doc ID: pub11132495
Abstract: Complete diallel crosses with seven varieties of black pericarp rice were conducted in one year to analyze the genetic effects on main mineral elements of Fe , Zn , Mn and P contents in kernels of parents and their F1S and F2S , using the full genetic model including triploid endosperm , cytoplasmic and maternal effects on quantitative traits of seeds in cereal crops . The results indicated that the contents of all the four mineral elements were controlled by seed direct genetic effects , maternal genetic effects as well as by cytoplasmic effects . The seed direct genetic effects were more important than the maternal genetic effects for Fe , Zn , Mn contents , and seed direct additive effects constituted a major part of their genetic effects , whereas seed direct additive , maternal additive and dominant effects formed the main part in the inheritance of P content . The heritabilities of seed direct effects of the 4 mineral element contents were all highly significant . The estimate values of narrow heritabilites of seed direct genetic effects were high for Fe , Zn and Mn contents , while those of seed and maternal effects were intermediate for P content . Therefore , more attention should be paid to the single plant selection and single grain selection based on the seed mineral element contents of hybrid offspring .
Score: 13.00
Title: Developmental behavior of gene expression for brown rice thickness under different environments .
Author: Shi CH Wu JG Wu P
Citation: V : 33 ( 4 ) P : 185-90 Year: 2002 Type: ARTICLE
Literature: oryza Field: abstract Doc ID: pub12203916
Abstract: The dynamic changes of genetic effects , including main effects , and genotype x environment ( GE ) interaction effects on brown rice thickness ( BRT ) across environments were investigated by using the developmental genetic models . Seven cytoplasmic male sterile lines of indica rice ( Oryza sativa L ) as females and five restoring lines as males were used in a factorial design to produce grains of F ( 1 ) s and F ( 2 ) s in two environments ( years ) for developmental genetic analysis . The results indicate that genetic effects , especially GE interaction effects of triploid endosperm genes , cytoplasm genes , and diploid maternal plant genes were important to the performance of BRT at various filling stages of rice . The BRT was genetically controlled by the net genetic effects of genes expressed at the early and late filling stages ( 1-7 days and 15-21 days after flowering , respectively ) . The differences in net genetic effects under different environments for endosperm , cytoplasm , and maternal plant genes were found , and the net GE interaction effects were more important to BRT at the early filling and mature stages of rice . Some net genetic effects , especially for net cytoplasm effects spasmodically expressed , were detected among filling stages . Higher additive and cytoplasm main effects , along with their interaction effects , were found , which would be useful for selection for BRT in breeding programs . The predicated genetic effects at different filling stages show that the parents of V20 and Xieqingzao were better than others for improving BRT of progenies .
Score: 13.00
Title: Does Cryotherapy Improve Outcomes With Soft it issue Injury?
Author: Hubbard TJ Denegar CR .
Citation: V : 39 ( 3 ) P : 278-279 Year: 2004 Type: ARTICLE
Literature: oryza Field: abstract Doc ID: pub15496998
Abstract: REFERENCE : Bleakley C , McDonough S , MacAuley D The use of ice in the treatment of acute soft-tissue injury : a systematic review of randomized controlled trials . Am J Sport Med . 2004 ; 32 : 251-261 . CLINICAL QUESTION : What is the clinical evidence base for cryotherapy use? DATA SOURCES : Studies were identified by using a computer-based literature search on a total of 8 databases : MEDLINE , Proquest , ISI Web of Science , Cumulative Index to Nursing and Allied Health ( CINAHL ) on Ovid , Allied and Complementary Medicine Database ( AMED ) on Ovid , Cochrane Database of Systematic Reviews , Cochrane Database of Abstracts of Reviews of Effectiveness , and Cochrane Controlled Trials Register ( Central ) . This was supplemented with citation tracking of relevant primary and review articles . Search terms included surgery , orthopaedics , sports injury , soft it issue injury , sprains and strains , contusions , athletic injury , acute , compression , cryotherapy , ice , RICE , andcold . STUDY SELECTION : To be included in the review , each study had to fulfill the following conditions : be a randomized , controlled trial of human subjects ; be published in English as a full paper ; include patients recovering from acute soft it issue or orthopaedic surgical interventions who received cryotherapy in inpatient , outpatient , or home-based treatment , in isolation or in combination with placebo or other therapies ; provide comparisons with no treatment , placebo , a different mode or protocol of cryotherapy , or other physiotherapeutic interventions ; and have outcome measures that included function ( subjective or objective ) , pain , swelling , or range of motion . DATA EXTRACTION : The study population , interventions , outcomes , follow-up , and reported results of the assessed trials were extracted and tabulated . The primary outcome measures were pain , swelling , and range of motion . Only 2 groups reported adequate data for return to normal function . All eligible articles were rated for methodologic quality using the PEDro scale . The PEDro scale is a checklist that examines the believability ( internal validity ) and the interpretability of trial quality . The 11-item checklist yields a maximum score of 10 if all criteria are satisfied . The intraclass correlation coefficient and kappa values are similar to those reported for 3 other frequently used quality scales ( Chalmers Scale , Jadad Scale , and Maastricht List ) . Two reviewers graded the articles , a method that has been reported to be more reliable than one evaluator . MAIN RESULTS : Specific search criteria identified 55 articles for review , of which 22 were eligible randomized , controlled clinical trials . The articles scores on the PEDro scale were low , ranging from 1 to 5 , with an average score of 3 . 4 . Five studies provided adequate information on the subjects baseline data , and only 3 studies concealed allocation during subject recruitment . No studies blinded their therapists administration of therapy , and just 1 study blinded subjects . Only 1 study included an intention-to-treat analysis . The average number of subjects in the studies was 66 . 7 ; however , only 1 group undertook a power analysis . The types of injuries varied widely ( eg , acute or surgical ) . No authors investigated subjects with muscle contusions or strains , and only 5 groups studied subjects with acute ligament sprains . The remaining 17 groups examined patients recovering from operative procedures ( anterior cruciate ligament repair , knee arthroscopy , lateral retinacular release , total knee and hip arthroplasties , and carpal tunnel release ) . Additionally , the mode of cryotherapy varied widely , as did the duration and frequency of cryotherapy application . The time period when cryotherapy was applied after injury ranged from immediately after injury to 1 to 3 days postinjury . Adequate information on the actual surface temperature of the cooling device was not provided in the selected studies . Most authors recorded outcome variables over short periods ( 1 week ) , with the longest reporting follow-ups of pain , swelling , and range of motion recorded at 4 weeks postinjury . Data in that study were insufficient to calculate effect size . Nine studies did not provide data of the key outcome measures , so individual study effect estimates could not be calculated . A total of 12 treatment comparisons were made . Ice submersion with simultaneous exercises was significantly more effective than heat and contrast therapy plus simultaneous exercises at reducing swelling . Ice was reported to be no different from ice and low-frequency or high-frequency electric stimulation in effect on swelling , pain , and range of motion . Ice alone seemed to be more effective than applying no form of cryotherapy after minor knee surgery in terms of pain , but no differences were reported for range of motion and girth . Continuous cryotherapy was associated with a significantly greater decrease in pain and wrist circumference after surgery than intermittent cryotherapy . Evidence was marginal that a single simultaneous treatment with ice and compression is no more effective than no cryotherapy after an ankle sprain . The authors reported ice to be no more effective than rehabilitation only with regard to pain , swelling , and range of motion . Ice and compression seemed to be significantly more effective than ice alone in terms of decreasing pain . Additionally , ice , compression , and a placebo injection reduced pain more than a placebo injection alone . Lastly , in 8 studies , there seemed to be little difference in the effectiveness of ice and compression compared with compression alone . Only 2 of the 8 groups reported significant differences in favor of ice and compression . CONCLUSIONS : Based on the available evidence , cryotherapy seems to be effective in decreasing pain . In comparison with other rehabilitation techniques , the efficacy of cryotherapy has been questioned . The exact effect of cryotherapy on more frequently treated acute injuries ( eg , muscle strains and contusions ) has not been fully elucidated . Additionally , the low methodologic quality of the available evidence is of concern . Many more high-quality studies are required to create evidence-based guidelines on the use of cryotherapy . These must focus on developing modes , durations , and frequencies of ice application that will optimize outcomes after injury .
Score: 12.00
Title: The Greenhouse effect : impacts of ultraviolet-B ( UV-B ) radiation , carbon dioxide ( CO2 ) , and ozone ( O3 ) on vegetation .
Author: Krupa SV Kickert RN .
Citation: V : 61 ( 4 ) P : 263-393 Year: Type: ARTICLE
Literature: oryza Field: abstract Doc ID: pub15092357
Abstract: There is a fast growing and an extremely serious international scientific , public and political concern regarding mans influence on the global climate . The decrease in stratospheric ozone ( O3 ) and the consequent possible increase in ultraviolet-B ( UV-B ) is a critical issue . In addition , tropospheric concentrations of greenhouse gases such as carbon dioxide ( CO2 ) , nitrous oxide ( N2O ) and methane ( CH4 ) are increasing . These phenomena , coupled with mans use of chlorofluorocarbons ( CFCs ) , chlorocarbons ( CCs ) , and organo-bromines ( OBs ) are considered to result in the modification of the earths O3 column and altered interactions between the stratosphere and the troposphere . A result of such interactions could be the global warming . As opposed to these processes , tropospheric O3 concentrations appear to be increasing in some parts of the world ( eg North America ) . Such tropospheric increases in O3 and particulate matter may offset any predicted increases in UV-B at those locations . Presently most general circulation models ( GCMs ) used to predict climate change are one or two-dimensional models . Application of satisfactory three-dimensional models is limited by the available computer power . Recent studies on radiative cloud forcing show that clouds may have an excess cooling effect to compensate for a doubling of global CO2 concentrations . There is a great deal of geographic patchiness or variability in climate . Use of global level average values fails to account for this variability . For example , in North America : 1 . there may be a decrease in the stratospheric O3 column ( 1-3% ) ; however , there appears to be an increase in tropospheric O3 concentrations ( 1-2%/year ) to compensate up to 20-30% loss in the total O3 column ; 2 . there appears to be an increase in tropospheric CO2 , N2O and CH4 at the rate of roughly 0 . 8% , 0 . 3% and 1-2% , respectively , per year ; 3 . there is a decrease in erythemal UV-B ; and 4 . there is a cooling of tropospheric air temperature due to radiative cloud forcing . The effects of UV-B , CO2 and O3 on plants have been studied under growth chamber , greenhouse and field conditions . Few studies , if any , have examined the joint effects of more than one variable on plant response . There are methodological problems associated with many of these experiments . Thus , while results obtained from these studies can assist in our understanding , they must be viewed with caution in the context of the real world and predictions into the future . Biomass responses of plants to enhanced UV-B can be negative ( adverse effect ) ; positive ( stimulatory effect ) or no effect ( tolerant ) . Sensitivity rankings have been developed for both crop and tree species . However , such rankings for UV-B do not consider dose-response curves . There are inconsistencies between the results obtained under controlled conditions versus field observations . Some of these inconsistencies appear due to the differences in responses between cultivars and varieties of a given plant species ; and differences in the experimental methodology and protocol used . Nevertheless , based on the available literature , listings of sensitive crop and native plant species to UV-B are provided . Historically , plant biologists have studied the effects of CO2 on plants for many decades . Experiments have been performed under growth chamber , greenhouse and field conditions . Evidence is presented for various plant species in the form of relative yield increases due to CO2 enrichment . Sensitivity rankings ( biomass response ) are agein provided for crops and native plant species . However , most publications on the numerical analysis of cause-effect relationships do not consider sensitivity analysis of the mode used . Ozone is considered to be the most phytotoxic regional scale air pollutant . In the pre-occupation of loss in the O3 column , any increases in tropospheric O3 concentrations may be undermined relative to vegetation effects . As with the other stress factors , the effects of O3 have been studied both under controlled and field conditions . Thboth under controlled and field conditions . The numerical explanation of cause-effect relationships of O3 is a much debated subject at the present time . Much of the controversy is directed toward the definition of the highly stochastic , O3 exposure dynamics in time and space . Nevertheless , sensitivity rankings ( biomass response ) are provided for crops and native vegetation . The joint effects of UV-B , CO2 and O3 are poorly understood . Based on the literature of plant response to individual stress factors and chemical and physical climatology of North America , we conclude that nine different crops may be sensitive to the joint effects : three grain and six vegetable crops ( sorghum , oat , rice , pea , bean , potato , lettuce , cucumber and tomato ) . In North America , we consider Ponderosa and loblolly pines as vulnerable among tree species . This conclusion should be moderated by the fact that there are few , if any , data on hardwood species . In conclusion there is much concern for global climate change and its possible effects on vegetation . While this is necessary , such a concern and any predictions must be tempered by the lack of sufficient knowledge . Experiments must be designed on an integrated and realistic basis to answer the question more definitively . This would require very close co-operation and communication among scientists from multiple disciplines . Decision makers must realize this need .
Score: 12.00
Title: Cytoplasm affects grain weight and filled-grain ratio in indica rice .
Author: Tao D Xu P Zhou J Deng X Li J Deng W Yang J Yang G Li Q Hu F
Citation: V : 12 P : 53 Year: 2011 Type: MEDLINE
Literature: oryza Field: abstract Doc ID: pub21631950
Abstract: BACKGROUND : Cytoplasmic effects on agronomic traits--involving cytoplasmic and nuclear genomes of either different species or different cultivars--are well documented in wheat but have seldom been demonstrated in rice ( Oryza sativa L ) . To detect cytoplasmic effects , we introgressed the nuclear genomes of three indica cultivars--Guichao 2 , Jiangchengkugu , and Dianrui 449--into the cytoplasms of six indica cultivars - Dijiaowujian , Shenglixian , Zhuzhan , Nantehao , Aizizhan , and Peta . These 18 nuclear substitution lines were evaluated during the winter season of 2005 in Sanya , Hainan , China , and during the summer season of 2006 in Kunming , Yunnan , China . The effects of 6 cytoplasm sources , 3 nucleus sources , 2 locations and their interactions were estimated for plant height , panicle length , panicle number per plant , spikelet number per panicle , grain weight , filled-grain ratio , and yield per plot . RESULTS : For five of the seven traits , analysis of variance showed that there were no significant cytoplasmic effects or interactions involving cytoplasmic effects . The effect of cytoplasm on 1000-grain weight was highly significant . Mean 1000-grain weight over the two locations in four of the six cytoplasms clustered close to the overall mean , whereas plants with Nantehao cytoplasm had a high , and those with Peta cytoplasm a low mean grain weight . There was a highly significant three-way interaction affecting filled-grain ratio . At Sanya , cytoplasms varied in very narrow ranges within nuclear backgrounds . Strong cytoplasmic effects were observed only at Kunming and in only two of the three nuclear backgrounds ; in the Jianchenkugu nuclear background , there was no evidence of strong cytoplasmic effects at either location . In the Dianrui 449 and Guichao 2 nuclear background evaluated at Kunming , filled-grain ratios of the six cytoplasms showed striking rank shifts CONCLUSIONS : We detected cytoplasmic variation for two agronomically important traits in indica rice . The cytoplasm source had a significant effect on grain weight across the two experimental locations . There was also a significant cytoplasmic effect on filled-grain ratio , but only in two of three nuclear background and at one of the two locations . The results extend our previous findings with japonica rice , suggesting that the selection of appropriate cytoplasmic germplasm is broadly important in rice breeding , and that cytoplasmic effects on some traits , such as filled-grain ratio , can not be generalized ; effects should be evaluated in the nuclear backgrounds of interest and at multiple locations .
Score: 11.00
Title: Heat-stress induced synthesis of chloroplast protein synthesis elongation factor ( EF-Tu ) in a heat-tolerant maize line .
Author: Bhadula SK Elthon TE Habben JE Helentjaris TG Jiao S Ristic Z
Citation: V : 212 ( 3 ) P : 359-66 Year: 2001 Type: ARTICLE
Literature: oryza Field: abstract Doc ID: pub11289600
Abstract: A heat-tolerant maize ( Zea mays L ) line , ZPBL 1304 , synthesizes a unique set of five heat-shock polypeptides of 45 kDa . Previous studies suggested that these polypeptides might play a role in the development of thermotolerance in maize ( Ristic et al , 1996 , J Plant Physiol . 149 : 424-432 ; Ristic et al , 1998 , J Plant Physiol . 153 : 497-505 ) . In the present study , we isolated these polypeptides , sequenced them , and investigated their subcellular distribution and origin . Of the five polypeptides of 45 kDa , three polypeptides , including the two most abundant ones , yielded amino acid sequences similar to the chloroplast and bacterial protein synthesis elongation factor ( EF-Tu ) . This was further confirmed using an antibody raised against maize EF-Tu , which showed a very strong reaction with the 45-kDa heatshock protein ( s ) . Studies on subcellular distribution and origin revealed that the 45-kDa polypeptides were localized to the chloroplasts , and were likely of nuclear origin . A full-length maize EF-Tu cDNA ( Zmeftu1 ) , previously isolated from the B73 line of maize , was used as a probe for northern blot analysis of RNA extracted from the ZPBL 1304 maize line ( the nucleotide and deduced amino acid sequences of Zmeftu1 are 88% identical to the rice EF-Tu sequence ) . Northern blots showed a 1 . 85-fold increase in steady-state levels of EF-Tu mRNA during heat stress . An increase in EF-Tu transcript levels during heat stress was accompanied by increased levels of the EF-Tu protein . Isolated chloroplasts from heat-stressed plants also had higher levels of EF-Tu as compared to control chloroplasts . The maize EF-Tu polypeptides showed > 80% sequence similarity with the bacterial EF-Tu , which has recently been shown to function as a molecular chaperone and to play a role in the protection of other proteins from thermal denaturation ( Caldas et al , 1998 , J Biol . Chem . 273 : 11478-11482 ) . It is hypothesized that chloroplast EF-Tu of the ZPBL 1304 maize line plays an important role in the development of thermotolerance .

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