903 resultados para soybean grain
Resumo:
Cell wall polysaccharides of wheat and rice endosperm are an important source of dietary fibre. Monoclonal antibodies specific to cell wall polysaccharides were used to determine polysaccharide dynamics during the development of both wheat and rice grain. Wheat and rice grain present near synchronous developmental processes and significantly different endosperm cell wall compositions, allowing the localisation of these polysaccharides to be related to developmental changes. Arabinoxylan (AX) and mixed-linkage glucan (MLG) have analogous cellular locations in both species, with deposition of AX and MLG coinciding with the start of grain filling. A glucuronoxylan (GUX) epitope was detected in rice, but not wheat endosperm cell walls. Callose has been reported to be associated with the formation of cell wall outgrowths during endosperm cellularisation and xyloglucan is here shown to be a component of these anticlinal extensions, occurring transiently in both species. Pectic homogalacturonan (HG) was abundant in cell walls of maternal tissues of wheat and rice grain, but only detected in endosperm cell walls of rice in an unesterified HG form. A rhamnogalacturonan-I (RG-I) backbone epitope was observed to be temporally regulated in both species, detected in endosperm cell walls from 12 DAA in rice and 20 DAA in wheat grain. Detection of the LM5 galactan epitope showed a clear distinction between wheat and rice, being detected at the earliest stages of development in rice endosperm cell walls, but not detected in wheat endosperm cell walls, only in maternal tissues. In contrast, the LM6 arabinan epitope was detected in both species around 8 DAA and was transient in wheat grain, but persisted in rice until maturity.
Resumo:
One Norwegian and one UK spring wheat cultivar, Bjarne and Cadenza, respectively, were grown in climate chambers to investigate the effects of lower to moderate temperatures during grain filling on the gluten quality. Two experiments were carried out with weekly fertilization until anthesis, while post-anthesis fertilization was applied in a third experiment. The proportions of different gluten proteins were affected by temperature in a similar manner for both cultivars when grown without post-anthesis fertilization. However, whereas low temperature strongly decreased %UPP for Cadenza, Bjarne had high %UPP at all temperature regimes. The results indicated that the assembly of glutenin polymers in Bjarne was less sensitive to variation in temperature than in Cadenza. Thus, our results suggested that the temperature influenced the proportion of different gluten proteins in both cultivars, while its effects on the assembly of the glutenin polymers were cultivar dependent. The duration of grain filling was longer at the lower temperatures, and this was associated with increased grain weight. Temperature had little effect on the amount of protein accumulated per grain, thus the proportion of proteins was strongly decreased at lower temperatures. This was to some extent, but not fully counteracted by post-anthesis fertilization.
Resumo:
Lipidomic analyses of milling and pearling fractions from wheat grain were carried out to determine differences in composition which could relate to the spatial distribution of lipids in the grain. Free fatty acids and triacylglycerols were major components in all fractions, but the relative contents of polar lipids varied, particularly lysophosphatidyl choline and digalactosyldiglyceride, which were enriched in flour fractions. By contrast, minor phospholipids were enriched in bran and offal fractions. The most abundant fatty acids in the analysed acyl lipids were C16:0 and C18:2 and their combinations, including C36:4 and C34:2. Phospholipids and galactolipids have been reported to have beneficial properties for bread making, while free fatty acids and triacylglycerols are considered detrimental. The subtle differences in the compositions of fractions determined in the present study could therefore underpin the production of flour fractions with optimised compositions for different end uses.
Resumo:
EXECUTIVE SUMMARY Background and context The Grain Legumes CRP was established to bring all research and development work on grain legumes within the CGIAR system under one umbrella. It was set up to provide public goods outcomes to serve the needs of the sustainable production and consumption of grain legumes in the developing world, capitalising upon their properties that enhance the natural resource base upon which production so unequivocally depends. The choice of species and research foci were finalised following extensive consultation with all stakeholders (though perhaps fewer end users), and cover all disciplines that contribute to long-lasting solutions to the issues of developing country production and consumption. ICRISAT leads Grain Legumes and is partnered by the CGIAR centers ICARDA, IITA and CIAT and a number of other important partners, both public and private, and of course farmers in the developed and developing world. Originally in mid-2012 Grain Legumes was structured around eight Product Lines (PL) (i.e. technological innovations) intersecting five Strategic Components (SC) (i.e. arranged as components along the value chain). However, in 2015, it was restructured along a more R4D output model leading to Intermediate Development Outcomes (IDOs). Thus five Flagship Projects (FP) more closely reflecting a systematic pipeline of progression from fundamental science, implementation of interventions and the development of capacity and partnerships to promote and adopt impactful outcomes: FP1) Managing Productivity through crop interactions with biotic and abiotic constraints; FP2) Determination of traits that address production constraints and opportunities; FP3) Trait Deployment of those traits through breeding; FP4) Seed Systems, post-harvest processing and nutrition; FP5) Capacity-Building and Partnerships. Another three cross-cutting FPs analyse the broader environment surrounding the adoption of outputs, the capitalising of investments in genomics research, and a focus on the Management and Governance of Grain Legumes: FP6) Knowledge, impacts, priorities and gender organisation; FP7) Tools and platforms for high throughput genotyping and bioinformatics; and FP8) Management and Governance. Five FPs focus on R4D; FPs 5 and 6 are considered cross-cutting; FP 7 has a technical focus and FP 8 has an overarching objective. Over the three year period since its inception in July 1012, Grain Legumes has had a total budget of $140 million, with $62M originally to come from W1/W2 and the remaining $78M to come from W3/bilateral. In actuality only $45M came from W1/W2 but $106M from W3/bilateral corresponding to 106% of expectation. Purpose, scope and objectives of the external evaluation Principally, the evaluation of Grain Legumes is to ensure that the program is progressing in an effective manner towards addressing the system-level outcomes of the CGIAR as they relate to grain legumes. In essence, the evaluation aims to provide essential evaluative information for decision-making by Program Management and its funders on issues such as extension, expansion and structuring of the program and adjustments in relevant parts of the program. Subsequent to the formal signing of the agreed terms of reference, the evaluation team was also invited to comment upon the mooted options for merging and/or disaggregating of Grain Legumes. The audiences are therefore manifold, from the CGIAR Fund Council and Consortium, the Boards of Trustees of the four component CGIAR centres, the Grain Legumes Steering, Management and Independent Advisory Committees, to the researchers and others involved in the delivery of R4D outcomes and their partner organisations. The evaluation was not only summative in measuring results from Grain Legumes at arm’s length; it was also formative in promoting learning and improvements, and developmental in nurturing adaption to transformational change with time. The evaluation report was written in a manner that allows for engagement of key partners and funders in a dialogue as to how to increase ownership and a common understanding of how the goals are to be achieved. We reviewed research undertaken before the CRPs but leading to impacts during Grain Legumes, and research commenced over the past 2.5 years. For related activities pre- and post-commencement of Grain Legumes, we reviewed the relevance of activities and their relation to CGIAR and the Grain Legumes goals, whether they were likely to lead to the outcomes and impacts as documented in the Grain Legumes proposal, and the quality of the science underpinning the likelihood to deliver outcomes. Throughout, we were cognisant of the extent of the reach of CGIAR centres’ activities, and those of stakeholders upon which the impact of CGIAR R4D depends. Within our remit we evaluated the original and modified management and governance structures, and all the processes/responsibilities managed within those structures. Besides the evaluation of the technical and managerial issues of Grain Legumes, we addressed cross-cutting issues of gender sensitivity, capacity building and the creation and nurturing of partnerships. The evaluation also has the objective to provide information relating to the development of full proposals for the new CRP funding cycle. The evaluation addressed six overarching questions developed from the TOR questions (listed in the Inception Report, 2015 [http://1drv.ms/1POQSZh] and others including cross-cutting issues, phrasing them within the context of traditional evaluation criteria: 1. Relevance: Global development, urbanisation and technological innovation are progressing rapidly, are the aims and focus of Grain Legumes coherent, robust, fit for purpose and relevant to the global community? 2. Efficiency: Is the structure and effectiveness of leadership across Grain Legumes developing efficient partnership management and project management across PLs? 3. Quality of science: Is Grain Legumes utilising a wide range of technologies in a way that will increase our fundamental understanding of the biology that underpins several PLs; and are collected data used in the most effective way? 4. Effectiveness: Are Product Lines strategic contributors to the overarching aims and vision for Grain Legumes? 5. Impact: Are the impact pathways that underlie each PL well defined, measureable and achievable; and are they sufficiently defined in terms of beneficiaries? Does progress towards achieving outputs and outcomes from the major research areas indicate a lasting benefit for CGIAR and the communities it serves? 6. Sustainability: Is Grain Legumes managing the increasing level of restricted funding in terms of program quality and effectiveness, including attracting and retaining quality staff? Questions for the evaluation of governance and management focused on accountability, transparency, the effectiveness and success of program execution, change management processes and communication methods, taking account of the effects of CGIAR reform. The three crosscutting issues were considered as follows: i) gender balance in program delivery, e.g. whether each PL is able to contribute to the increased income, food security, nutrition, environmental and resource conservation for resource-poor women and men existing in rural livelihoods; ii) are internal and external capacity gaps identified/met, is capacity effectively developed within each product line, and are staff at all levels engaged in contributing ideas towards capacity building; and iii) is there effective involvement of partners in research and activity programming, what are the criteria for developing partnerships, how they are formalised and how is communication between partners and within Grain Legumes managed? It was not in remit to search for output, outcomes or impact, however as highlighted later, much of our time was spent on searching for information to support claims of impact, since Grain Legumes had no effective dedicated M&E in place at the time of undertaking the review. Approach and methodology The evaluation was conducted when Grain Legumes had been operational for approximately 3 years. The approach and methodology followed that outlined in the Inception Report [http://1drv.ms/1POQSZh]. The CCEE Team based its findings, conclusions and recommendations on data collection from several sources: review of program documents, communications with the CO, minutes and presentations from all management and governance committee meetings review of previous assessments and evaluations sampling of Grain Legume projects in 7 countries1 more than 66 face to face interviews, a further 133 persons in groups and 4 phone/Skype conversations: ICRISAT, ICARDA, CIAT and IITA staff, partners and stakeholders. Meetings with one Independent Science and Partnership Council (ISPC) member. meetings with over 100 people in 16 external groups, such as farmers’ groups online survey completed by 126 (33.4%) scientists who contribute to Grain Legumes and a number of non-CGIAR partners and Management representatives bibliometric review of 10 publications within each PL to qualitatively assess the design, conduct, analysis and presentation of results quantitative and qualitative self-assessment of the contributions of each of the PLs to the six criteria and 3 cross-cutting issues of evaluation mentioned above completed by PLCs (see below). We reviewed the Logical Framework that underpins the desired Goals, or Impacts of Grain Legumes, and the links between the outputs and inputs as they related to the organisational units of Grain Legumes. The logical framework approach to planning and management of Grain Legumes activities implies a linear process, leading from activities, outputs, outcomes, to impacts, but within such an approach there may be room for a more systems dynamics approach allowing for feedback at every step and within every step, in order to refine and improve upon the respective activities as new results, ideas, and directions come to light. We then developed a matrix that summarised quantitatively and qualitatively the contributions of each of the PLs to the six criteria and 3 cross-cutting issues of evaluation mentioned above. Main findings and conclusions Grain legume production and consumption remain of great importance to the food security of not inconsiderable populations in the developing world, and merit sustained research investment. We conclude that Grain Legumes continues to contribute significant returns to research investments by the CGIAR, and such investment should continue. The global research community looks to the CGIAR for leadership in Grain legumes, but needs to be assured of value adding when bringing CGIAR centres under the expected umbrella of synergy. However, there is considerable scope for improving the efficiency with which outcomes are achieved. We note that an absence of an effective M&E has hampered the assessment of the effectiveness of proposed impact pathways. Likewise progress has been hampered by the limited numbers of research partnerships with Advanced Institutes and by budgetary constraints (lamented for their stifling effects on continuation of ongoing exciting research). The unworkable management structure constrains the CRP Director’s leadership role; responsibility without authority will never lead to effective outcomes. Good fortune is responsible for many of the successes of Grain Legumes, underpinned by a devoted work force across the participating CGIAR centres and partners. The quality of the science is not uniformly high, and we believe that mentoring of scientists should be given priority where quality is poor. Simplified yet informative reporting is an imperative to this. World class science underpins the identification of, and molecular basis for, traits important for yield improvement and this expertise should be extended to all grain legume species, capitalising upon the germplasm collections. The linking of Grain Legumes with regional research and development consortia has been very successful, with outcomes aligning with those of Grain Legumes. We see that with declining funding consolidation of research effort based on likely successes will be necessary, and welcome the move afoot to incorporate grain legumes into an agri-food system focused on successful value chains that deliver sustainable outcomes. Relevance and Strategy Grain Legumes has geographic and disciplinary relevance, addressing the major supply chain issues of variety development seed system and agronomy, with some attention to quality and postharvest marketing systems. The CRP has provided the opportunity to cut ongoing and to initiate new research. Research funded by the Gates Foundation (Anon, 2014) suggests that the need for improvement is greatest in Africa and advocates reducing the number of crop by country combinations when resources are sparse. The lesser research investment in Latin America, however, is not in line with the regions’ dependency on legumes. In spite of the fact that there is no evidence of strong inter-partner CGIAR centre or internal synergy, the program is still moving ahead on most fronts in line with the overall project logframe. This is in spite of continual pushing and pulling by in particular donors and the CO. However, to quantify real impact, we believe Grain Legumes must have access to reliable baseline data on production and consumption, and this is missing. Similarly, there is little evidence of the proposed ‘Inclusive Market Oriented Development’ (IMOD) framework being used to assist with priority setting. The product lines, eight of which cover most of the historical programmes in place in the partner CGIAR centres at the commencement of the Grain Legumes, do not cover all the constraints for formal constraints analysis was not undertaken at the inception of the Grain Legumes, and some of this additionally identified research is undertaken under the umbrella of the FPs; this needs to be rationalised. We found the PLs to be isolated in activity, even with minimally-integrated activities within each PL, with little evidence of synergy between PLs. Even though the SCs should ensure a systems approach, as with the new FPs, we did not get a feel that this is so. The underplaying of agronomy, and production practices may be one reason for this. We believe that treating legume crops as if they were horticultural crops will increase farmer returns from investment. The choice of Flagship Projects makes sense, with the flow of activity firstly around crop management and agronomy followed by the logical sequence of trait discovery, incorporation into improved varieties, dissemination of those varieties through appropriate seed chains leading to market impacts, and the capacity building required at all steps. One obvious omission, however, is the lack of a central and strategic policy on the role of transgenics in Grain Legumes. We found four notable comparative advantages for Grain Legumes: the access to germplasm of component species, the use of the phenotyping facility at ICRISAT, the approach for village level industry for IPM, and the emphasis on hybrid pigeonpea. Efficiency Each centre has strong control of, and emphasis on, their ‘species’ domains, and ownership of the same detracts from possible synergy. Without synergy or value add, the Grain Legumes brings with it no comparative advantage over each centre continuing their own pre-CRP research agendas. We found little evidence of integration of programmes between centres and almost no cross-centre authorship of publications, such as could have occurred with the integrated cross-centre approaches to stress tolerance including crop modelling: the one publication (Gaur et al., 2015) on heat tolerance by ICRISAT, CIAT and ICARDA does not provide any keys to inter-centre collaboration. The integration of each centre with NARS and university research programmes is good, but the cross-centre links with NARS are poor. A better coordinated integration with Grain Legumes, , rather than through the individual centres, may reduce transactions costs for NARS, Monitoring and evaluation is, as noted throughout our report, one area of Grain Legumes research management that has not been given the attention it should have received. If it had have received proper attention, some of the issues of poor efficiency might have been nipped in the bud. A strong monitoring and evaluation system would have provided the baseline data and set the milestones that would have allowed both efficiency and effectiveness to be better appraised. We found no attempt to define comparative advantages of the CGIAR centres and their R4D activities, although practice showed the better grasp of CIAT in developing innovative seed distribution systems. During field visits and interviews, the CCEE Team observed shortcomings in the communication processes within Grain Legumes and with the broader scientific community and the public. For example, the public face of the program on the internet is out of date. Survey findings, however, suggest that information is shared freely and routinely within the PL within which scientists work. Some external issues, such as those with funding, low W1/W2 and poor sustainability of funding (especially if funding is top heavy with a few agencies), undermine research investment and confidence of partners in the system (e.g. as voiced by researchers working on crops and countries not included in TL III and the cessation of ongoing competitively-funded projects especially in India), but other issues attributable to the governance and management of the Grain Legumes, such as opaque integration of W3/bilaterals with W1/W2 funding require attention. Offsetting this, the existence of the Grain Legumes did mobilise additional funding [that it would not have if Grain Legumes did not exist]. We were concerned that Grain Legumes is simply not recognised outside of the CRP, with a limited www presence and centres promote themselves, rather than Grain Legumes (with exception in IITA). This is not a good move if one wishes to increase investment in the Grain Legumes. Although funding agencies require cost:benefit ratios, for example for each PL we faced difficulty in determining comparative value for money between investment in different types of research, and in being able to clearly attribute research and development outcomes to financial investment. There was also a time CCEE frame issue too. There is poor interaction with the private sector, notably in areas where they have a comparative financial advantage. We questioned in particular the apparent lack of interaction with the major agro-chemical companies, with respect to the development of herbicide tolerant (HT) grain legumes and the lack of evidence that the regulatory and trade aspects related to herbicide tolerant crops had been considered. Quality of science The quality of the science is highly variable across Grain Legumes, with pockets of real excellence that are linked to good levels of productivity, whereas other PLs are struggling to deliver quality publications, and outputs and outcomes that are based on these. There is much evidence of gradualism in terms of research output and outcomes, i.e. essentially the same activities that were ongoing at the time of the launch of Grain Legumes are still in place. However, there are examples of game changers including those from valuable investments in genomics, phenotyping, and bio-control. We were pleased to see large proportions of collaboration on publications with non-CGIAR centres, reflecting cooperation with partners in developed and developing countries. The value of collaboration when ensuring quality of science cannot be stressed highly enough both within the CRP, and with other global and national partners. PLs should be given incentives to collaborate with other CRPs and external institutions. There is little cohesion between PLs and with other CRPs as evidenced by publications, although there are some exceptions. We suspect the reasons for this are driven by funding. Productivity from the different PLs is also highly variable and it is not clear what other activities staff are engaged in since, in some PLs, they do not appear to lead to quality publications. Effectiveness Grain Legumes has been very effective in addressing component issues of research, but not the continuum from variety development to legumes on someone’s dinner plate. Our overall assessment of the effectiveness of Grain Legumes in stimulating synergy, innovation and impact indicate that gradualism is more prevalent than innovation. It also shows, as do publications, that there is little integration of disciplines or a focus on ‘systems’. The absence of socio-economists from research teams is evident in the general lack of an end user focus. However, research on genomics, plant breeding and seed systems have made great strides forward, on the brink of delivering impact. Agronomy has been a poor sister, but some of the competitive grants within Grain Legumes have unearthed some potential game changers, such as objective use of transplanting as an agronomic practice. As mentioned earlier, the lack of effective M&E (however, this was part of some major projects such as TL II/TL III), and therefore the ability to monitor impact pathways and achievement of impact, implies no systematic management of data. This creates difficulty when attempting to evaluate the achievement of the Grain Legumes objectives. One might have expected at least one attempt to try to develop publications between centres arguing for similar biologies/research approaches, bringing species together under one umbrella, but we did not find any evidence for this. It is most unfortunate that, due to budgetary cuts, the new ‘schemes’, e.g. competitive grants and scholarships, were cut off before gaining a foothold. With 8 species addressed by Grain Legumes, it is not unexpected that there will be little evidence of shared protocols across centres/species. One rare example was that hosted by the United States Department of Agriculture (USDA) on shared methods for phenotyping of legume germplasm. Researchers from CIAT, IITA, ICRISAT and three USDA stations attended, focusing in simple canopy temperature and root morphology measurements. It is our belief that as a set of research centres, the CGIAR centres should be focusing on the research for which they have a comparative advantage. While imposing the restructure to FPs, which is fine for development objectives and outcomes (funded through W3/bilateral), it is less so for a research institute, and the structure should not detract from the more basic work expected of an international CGIAR centre (or set of centres as in a CRP). Impact It is well known that research does not always lead to scientific breakthroughs. Also, activities such as plant breeding are long term; making impacts difficult to assess. We believe that sufficient progress with genomics and associated research has been made to warrant impact, but we are unable to quantify the levels of impact, or the timeframe for the same. Work in Grain Legumes has enormous potential for real impact in scientific research, commercial, farming, smallholder and household communities, much of which is being realised. However, the PLs need to become more adept at providing convincing cases that are strongly evidenced for these impacts, as this is likely to be a key factor in leveraging future funding. Claimed gains must be referenced against baseline data, and these are not always readily available. The CCEE Team realises that such impact evaluation represents a significant drain on resources, and Grain Legumes should determine whether the balance of costs to benefits favours such investment. Interviews conducted by the CCEE during site visits showed that PLs are quantifying the area of adoption of varieties, but in most cases they are not measuring the impact on environment, health/nutrition. Since the health and nutritional benefits and the environmental gains from growing legumes are major arguments for supporting grain legume research, the community is currently missing substantial opportunities to strengthen its own case for continued support. Whilst there are some impressive examples of considering the whole value chain, e.g. white beans from production through to export; in the main, the pipeline to end user is somewhat piece-meal, with no clear definition of the end user nor differential responsibility of Grain Legumes and of partners. The lack of robust time-defined impact pathways is highlighted in Section 7.4, and even though developed for PL5, timeframes are essential for measuring progress against prediction. Sustainability In summary, there is general acknowledgement that future funding is likely to become more limited, specifically in W1&2 and there is understandable concern over the support for the staff and basic infrastructure that underpin the Grain Legumes programme. For example, it is reported that staffing in parts of CIAT has been dependent on W1&2 and that this is too unstable to re-establish a critical mass. The present system whereby W3 and bilateral projects do not pay a realistic level of overheads means that such projects are being effectively subsidised by W1&2. This position is not sustainable in the long term as there will be a progressive but definite loss of basic skills and resources in the core centres. The only obvious options to prevent this outcome include a severe reduction in the fixed costs of the centres and/or a refusal to accept W3 and bilateral funding with an inadequate overhead component. In the latter case, there is an obvious danger that funders will move their resources away from the CGIAR system towards other, perhaps less expensive, suppliers of research, and possibly more relevant development expertise. This issue must be addressed. As the Grain Legumes moves into the future, and if sustainable funding cannot be assured, decisions must be made concerning a reduction in activities, keeping some caretaker breeding maintenance, and focus (as has TL III) on fewer species and a reduced geographic focus. Cross cutting issues: Gender, capacity building and partnerships Gender is not mainstreamed, but there is some evidence that this is improving, especially with dedicated gender specialists and the slow integration of gender across CRPs. There is a need to approach gender through the vision of agriculture as a social practice, with recognition of what changes will be acceptable culturally and what not, and capitalising upon the perceived and actual features of production and processing that grain legumes are primarily women-based crops. Gender awareness may be high among Scientists, but it appears to be a predominantly passive attribute with few proactively seeking opportunities for gender equity. It is, however, a sound sensitivity base on which to build. Nevertheless, examples of notable gender initiatives were identified during field visits. For example, in Benin, the development of biocontrol technologies has enthusiastically integrated diversity, engaging with women farmers’ and youths while maintaining cultural norms. Women are gathering and processing, youths are taking the product to market. The implication is that several groups benefit, rather than domination by the majority group. In Malawi, innovative approaches have been developed to improving nutrition for children, such as incorporating nutrient enriched bean flour products into snacks. In India, scientists collaborating with gender scientists and socio-economists are identifying the impact of mechanical harvesting on agricultural labour and the potential displacement of female labourers. In Kenya, a novel initiative is improving the accessibility of certified seed for new varieties. Seed suppliers have introduced small packs of grain legume seed at low unit cost, which are being purchased by young people and women. Capacity building efforts for external partners are not clearly aligned with the research mandate and delivery of Grain Legumes. However, there are a number of training activities that are being undertaken by Grain Legumes, largely through the W3/bilateral project. Gender balance never reaches parity, but it appears that efforts are made to include female participants. Within the evaluation timeframe it was not possible to conduct external surveys to further validate or review external capacity building efforts in Grain Legumes. Training of scientists is significant, with >40 benefiting. Postgraduate training is varied across PLs, and there is some opportunity to increase the numbers being supervised. We consider that support for postgraduates at ICRISAT could be better coordinated, satisfying more of the students’ needs. It is important, however, to follow up investments in capacity building by monitoring effectiveness, career progressions and so on. Training activities appear to be rather centre-specific, not following a coordinated programme managed by, nor at the level of, the Grain Legumes. Numbers of persons trained and their gender are important, but a measure of the effectiveness of the training is more important. Although optimism is expressed by the great majority of Research Managers that partnerships were working well to leverage knowledge and research capacities, scientists have a less favourable view, particularly in terms of their incentives to participate. It seems likely that the activities taking place within Grain Legumes were, in the most part, continuations of previous collaborations. This is not surprising in light of the reduction in the emphasis on partnerships as Grain Legumes evolved to a funded project, and the consequent lack of opportunity and ambition for establishing novel partnerships. Where they exist, partnerships are good on the whole, especially with US. They could be expanded where comparative advantages exist (for example with Canada and Australia for machine harvestable legumes), but some earlier identified partnerships, e.g. with Turkey, have not been capitalised upon. Others experience problems of variety access (the embargo on exports of some sources of materials from India), yet others do have relevance e.g. imported Brazilian varieties in pre-release in Ethiopia (even though two of the three are from CIAT materials). Governance and Management The standard format of committee structure and responsibilities is common to other CRPs, as are the attendant problems. One of the major problems is that the Grain Legumes Director has responsibility but no authority; hence, even with the support of the RMC, the Director is unable to ‘direct’ in the literal sense of the work the activities of Grain Legumes. We also see the same sense of helplessness with the role of the PLCs. They have responsibility but no authority in managing the affairs of their PL, and they have no access to funds with which to promote intellectual collaboration and cooperation. Minutes from governance and management meetings do not reflect the compromised weak position of the Director and the associated difficulties in the management of Grain Legumes. Nor do the minutes reflect concerns about the amount of time spent by scientists in meetings for planning, integration, evaluation and reporting. Many scientists reported significant opportunity costs in participating in the ongoing imposed [by the CO] evolution of Grain Legumes and CRPs in general. The changes brought in by the CO have not helped promote any greater authority and capacity of the Grain Legumes Director to direct. Likewise, they do not address any of the issues with the conflict of interest in having the Lead Centre chair the Steering Committee. Indeed, we believe that the combining of the Steering Committee with the Independent Advisory Committee, besides becoming unwieldy in number, annuls any sense of independence in advice offered to the Grain Legumes management. We have concerns with the declining proportion of W1/W2 funds (as expressed in the section on Sustainability), and believe that when basic financial planning takes place, integration of W1/W2 and W3/bilateral sources must occur, and be linked to anticipated outcomes and impacts. This will ensure a close alignment of collaborators’ and partners’ objectives and contributions to that of the Grain Legumes. We also queried the process for, and the formality, or lack of, surrounding, the approval of annual budgets, and the level of priority setting when budgets are cut. Recommendations for Grain Legumes The CCEE Team makes the following recommendations, critical issues are highlighted in bold, and those that require action by an entity other than the Grain Legumes Research Management Committee or Project Management united are identified in a footnote. Relevance and Strategy Recommendation 1: A period of consistency is necessary to raise confidence, morale and trust across scientists, managers and partners to foster the assembly of enduring Grain Legumes outcomes2. There needs to be a concerted effort to undertake baseline studies and to implement a robust M&E activity during this period. Without these data the foundation for integrated research in grain legumes is jeopardised. There is a strong need to link more closely with the private sector, especially where there are financial and other comparative advantages to do so. Recommendation 2: The agronomic and physiological trait targets of Grain Legumes (tolerance to changing climate patterns, to the pests and diseases of today and of the future, incorporation of quality traits and adaptations to intensive production systems [machine-harvestability and herbicide tolerance], and short season high yielding characters) are all worthy of continued investment when selecting for improved varieties. There needs to be a common strategy, implemented across centres and species, as to how to address these trait targets through conventional and modern breeding approaches, but only if adequate funding is assured and secured and if a consistency and unity of purpose can be achieved across a large-scale. This should take the form of cross-species coordinated research programmes to address these breeding targets that cooperate across centres and make efficient use of facilities and other resources. The CRP should undertake a detailed strategic review of the role of transgenics across the range of targets in the mandate crops. Efficiency Recommendation 3: The lack of an effective M&E process is a significant omission, not least in terms of more efficient use of resources and the lack of baseline data with which to measure impact, and must be rectified. Reinforcing Recommendation 1, an effective M&E system initially directed towards baseline studies must be implemented. Transaction costs may be reduced through bilateral projects, which are seen as more cost effective than W1/W2 where transaction costs are disproportionately higher. Recommendation 4: To improve communication and coordination within the CRP, and with a broader audience: There is a priority need for a central database containing, names of staff associated with Grain Legumes and their time commitments, their responsibilities, and involvement in CRP activities, their progress and achievements, their publications, plans of training, travel, and other opportunities for interaction. Regular global meetings of staff involved in managing PLs, the entire CRP management staff and the IAC are essential for effective coordination of all activity within Grain Legumes. The website must be given a complete overhaul and improvement and then regular maintenance must be provided to keep it current. Quality of Science Recommendation 5: It is essential to continue investment in good science and to institute a change from gradualism in research output and outcomes to an expectation of innovative and concrete achievements that can be attributed clearly to people, centres and core facilities. A cost:benefit analysis and subsequent strategic planning must be undertaken to justify further investment in the genomics and phenotyping facilities at ICRISAT especially as such technologies advance rapidly. Strategic planning and coordination must also be implemented for capitalising on the investment in crop simulation modelling. (The phenotyping facility of ICRISAT needs to focus on delivering some outcomes, not only outputs.) PLs should be given incentives to collaborate with other CRPs and external institutions. The CCEE recommends special recognition of high quality collaborative papers, thereby encouraging increased quality of the research programmes and widening the penetration of research impacts. More importance should be placed on the quality of publication, rather than quantity of outputs and there should be recognition of other types of outputs from Grain Legumes. The CRP Director must be party to this. If staff are engaged in activities that relate more to impact than publication then this needs to be monitored and recorded and a clearer understanding developed of what constitutes a pathway to impact and how success of such activities can be evaluated. A system must be devised and incorporated into the M&E to enable recognition of other types of outputs (non- publication based) from Grain Legumes, e.g. varieties for breeders. Effectiveness Recommendation 6: To develop greater synergy, Grain Legumes should review management processes and the direction of research activities. In particular, far more extensive integration of research and knowledge exchange should take place across both African and Asian continents so that the best aspects of both can be shared. A multidisciplinary approach is recommended that considers processing solutions, as well as breeding solutions, to capitalise upon the nutritional benefits of the grain legume crops. We recommend: A better collaboration with social scientists at the design stage of experiments in order to improve the utility of the work carried out and to understand its reach. Supporting3 the adoption of best practice electronic data collection, central storage and open access, particularly of genomic data, for public use. Given the focus on the link between phenotyping and genotyping, we note that there is a lack of congruence between the populations that are being phenotyped and those being genotyped, and therefore these could be better aligned within each species. Concentrating investment external to Grain Legumes on scaling up production of varieties with the most promising trait profiles to meet the basic seed requirement. Developing a more holistic approach that coordinates an understanding of the disease pathology and epidemiology, and of new chemicals before they become commercially available, together with agronomic practice such that recommendations can be made for growers. Continuing work to establish whether agronomic factors hold true in different environments and to assess GxE effects within breeding programmes. Such rigorous trial practices should be used to inform the evaluation of breeding lines and to provide phenotype data to associate with markers for traits such as heat, drought and herbicide tolerance. Considering grain legumes as if they were vegetable crops in terms of the strategy for intensification of production, both from the management perspective and for seed systems, will be a useful development objective into the future. This will bring about more rapid intensification and is likely to increase farmer returns from investment. Recommendation 7: The CGIAR centres should focus in on the research for which they have a comparative advantage. While imposing the restructure to FPs, which is fine for development objectives and outcomes (funded through W3/bilateral) it is less so for a research institute, and should not detract from the more basic work expected of an international CGIAR centre (or set of centres in a CRP). Collaborative approaches should be explored within Grain Legumes, e.g. similar biologies/research approaches, bringing species together under one umbrella. Similarly better alignment is needed to address the lack of congruence between the populations that are being phenotyped and those being genotyped. Despite positive impacts from research in genomics, plant breeding and seed systems, the lack of an effective M&E, already mentioned elsewhere, has reduced the ability to monitor impact pathways. This must be addressed. The absence of socio-economists from research teams is evident in the general lack of an end user focus. Responsibilities of the different actors in the whole value chain must be considered and identified when developing impact targets, and the pathway leading to them, for individual projects. People with socio-economist skills must be part of the team from project inception so that appropriate frameworks are incorporated for measuring and influencing sociological and economic changes brought about by Grain Legumes research. Impact Recommendation 8: PLs need to become more adept at providing convincing cases in which impact is strongly evidenced, as this is likely to be a key factor in leveraging future funding. Claimed gains must be referenced against baseline data, and these are not always readily available. The CCEE Team realises that such impact evaluation represents a significant drain on resources, and Grain Legumes should determine whether the balance of costs to benefits favours such investment. It is essential that Grain Legumes provides training to staff on what constitutes impact and how it can be recorded. Specific, rather than generalised, potential impacts arising from activity within Grain Legumes should be defined at the time of justifying the programme of work and a pathway to impact should form part of the documentation prepared ahead of a piece of research commencing. . In other words, centres should submit work plans to Grain Legumes before they are undertaken using W1/W2 funds Recommendation 9: The reporting activity must be streamlined to a single (brief) format that can be used to report to Grain Legumes, Centres and to donors for special project activities4. Sustainability Recommendation 10: As Grain Legumes moves into the future, and if sustainable funding cannot be assured, decisions must be made concerning a reduction in activities, keeping some caretaker breeding maintenance, and focus (as has TL III) on fewer species and a reduced geographic focus. Zeigler (Director General of IRRI) states “…time and effort would be better spent … making tough decisions about which programs deserve the precious support.” The present system whereby W3 and bilateral projects do not pay a realistic level of overheads means that such projects are being effectively subsidised by W1&2 and there will be a progressive but definite loss of basic skills and resources in the core centres. To prevent this outcome it is necessary to significantly reduce the fixed costs of the centres and/or refuse to accept W3 and bilateral funding without an adequate overhead component. In the absence of long term certainty, the scale of the budget allocated to each of the new CRPs should be very conservative, a feature that can only be achieved by restricting/reducing the scope, probably quite significantly. Cross cutting issues: Gender, capacity building and partnerships Recommendation 11: The challenge for Grain Legumes is to achieve pro-active gender mainstreaming, which facilitates opportunities for gender diversity within all activities, from employment processes through research to end users. Strategic measurable gender indicators need to be embedded in research design, for instance, through specific IDOs for each of the flagships projects. Accurate baseline data are also required to facilitate M&E reviews of progress. Implementation of the Gender Strategy is the responsibility of everyone, not solely the Gender Team. Thus, ownership could be encouraged by setting personal development for key personnel objectives with specific outcomes, e.g. employment practices or research outcomes. Recognising the positive gender initiatives in progress or planned, feedback must be communicated and integrated into broader research planning to share opportunities, methods and outcomes. In addition to promoting gender equity in research, Grain Legumes also needs to ensure that working environments are gender sensitive and that recruitment processes, including promotion opportunities are equitable. Gender imbalance in management should be actively examined to identify further opportunities for developing female leadership. Recommendation 12: It is recommended that a training plan be devised to ensure that capacity building efforts are more clearly aligned with the research mandate, delivery and timeframe of Grain Legumes. Moreover, we recommend that ICRISAT develop a strategy to treat their new cohort of researchers more equitably in the future. Recommendation 13: To develop a more coherent strategic programme designed to eliminate overlap and promote synergy between programmes with common aims, Grain Legumes should hold a meeting with a range of partners. Governance Recommendation 14: Governance processes should be re-assessed and the structure altered to ensure that the Grain Legumes Director has the authority and budget control to drive the execution of strategy. The ISC should be truly independent and given the power to influence strategic decisions before they become final. We also recommend that PLCs are provided with the authority to manage the direction and finances of their PL; and that ring-fenced funds are provided for the promotion of collaboration, coordination and staff training5. The way ahead In our view, having seen the ineffectiveness of much of the attempts [or lack of attempts] to harness synergies between multiple centres, and of the strength in few or sole centre partnerships, we believe that there is little to justify a full retention of the 8 legume species and 4 CGIAR centres in a CRP. TL I and II and PABRA have shown to be reasonably good cross-centre and single centre integrated programmes, but even they suffer from incomplete value chain approaches to increasing rural incomes while increasing food and nutritional security; they both need multi-faceted solutions which are not immediately forthcoming from Grain Legumes. It is important to embed Grain Legumes research within the agri-food systems these crops serve. Figure ES1 broadly shows the perceived current and potential degrees of synergy between centres, PLs and species, and is discussed more in the text. It is clear that the value chains for individual species from trait determination to nutritional impact have more cohesion than do the individual activities (e.g. trait deployment) across species. For this reason we believe that the future for research in Grain Legumes is best addressed by focusing on each of the species separately, and within an ecosystem framework; any synergy for research across species can be effected through communication and not necessarily through obligatory cooperative research. The ecosystem framework will allow for strengthening of agronomy type systems research, the arguments for benefits of inclusion of grain legumes in cropping systems, which is notable by its absence in much of what Grain Legumes currently undertakes. Figure ES1. Current and potential degrees of synergy between centres, PLs and crop species We therefore agree with the innovation in agri-food systems approach of the CG, and believe that Grain Legumes rightly belongs in the Dryland Cereals and Legumes Agri-food Systems. We believe that the option of combining the crops of dryland cereals and legumes in the cereal-legume-livestock systems of subsistence farming communities for whole-farm productivity is closest to the best way forward. Indeed the inclusion of grain legumes may not warrant even a CRP alone, rather the legume components should fit in with the major crops that determine the production systems. Legumes will always be subservient to the major cereals, as necessary adjuncts to the whole production system, providing both nutritional diversity and environmental services, neither achievable from cereals alone. Figure ES2. Most suitable option for integration of Grain Legumes and Dryland Cereals into an Agri-Food Systems CRP Most suitable option for integration of Grain Legumes and Dryland Cereals into an Agri-Food Systems CRP, which Incorporates ex-Dryland Systems, Dryland Cereals, Grain Legumes, some HumidTropics, some ex-Livestock &Fisheries into a new CRP Will cover full agri-food system VC for all 8 legumes in all ecologies, but must interact (dock) with the relevant AFS-CRPs for the dominant cereal in the relevant ecology Hence, will need to negotiate with other Agrifood Systems-CRPs on who does what for legumes In addition, responsible for sorghum and millet in the mixed dryland crop-livestock agro-ecologies For major game changers to be effected, we believe that the game has to change, and there is little evidence of this. The direction of CRPs is the correct route, but the journey has not yet come to its destination. A major change of game [such as the adoption of a Flagship Project approach as exemplified by the Australian CSIRO – where flagships contract services from centres of research excellence] would be painful to implant. The CGIAR system is going down the right pathway but it has not gone far enough.
Resumo:
Soybean, an important source of vegetable oils and proteins for humans, has undergone significant phenotypic changes during domestication and improvement. However, there is limited knowledge about genes related to these domesticated and improved traits, such as flowering time, seed development, alkaline-salt tolerance, and seed oil content (SOC). In this study, more than 106,000 single nucleotide polymorphisms (SNPs) were identified by restriction site associated DNA sequencing of 14 wild, 153 landrace, and 119 bred soybean accessions, and 198 candidate domestication regions (CDRs) were identified via multiple genetic diversity analyses. Of the 1489 candidate domestication genes (CDGs) within these CDRs, a total of 330 CDGs were related to the above four traits in the domestication, gene ontology (GO) enrichment, gene expression, and pathway analyses. Eighteen, 60, 66, and 10 of the 330 CDGs were significantly associated with the above four traits, respectively. Of 134 traitassociated CDGs, 29 overlapped with previous CDGs, 11 were consistent with candidate genes in previous trait association studies, and 66 were covered by the domesticated and improved quantitative trait loci or their adjacent regions, having six common CDGs, such as one functionally characterized gene Glyma15 g17480 (GmZTL3). Of the 68 seed size (SS) and SOC CDGs, 37 were further confirmed by gene expression analysis. In addition, eight genes were found to be related to artificial selection during modern breeding. Therefore, this study provides an integrated method for efficiently identifying CDGs and valuable information for domestication and genetic research.
Resumo:
The effects of simulated additional rain (ear wetting, 25 mm) or of rain shelter imposed at different periods after anthesis on grain quality at maturity and the dynamics of grain filling and desiccation were investigated in UK field-grown crops of wheat (Triticum aestivum L., cvar Tybalt) in 2011 and in 2012 when June–August rainfall was 255.0 and 214.6 mm, respectively, and above the decadal mean (157.4 mm). Grain filling and desiccation were quantified well by broken-stick regressions and Gompertz curves, respectively. Rain shelter for 56 (2011) or 70 d (2012) after anthesis, and to a lesser extent during late maturation only, resulted in more rapid desiccation and hence progress to harvest maturity whereas ear wetting had negligible effects, even when applied four times. Grain-filling duration was also affected as above in 2011, but with no significant effect in 2012. In both years, there were strong positive associations between final grain dry weight and duration of filling. The treatments affected all grain quality traits in 2011: nitrogen (N) and sulphur (S) concentrations, N:S ratio, sodium dodecyl sulphate (SDS) sedimentation volume, Hagberg Falling Number (HFN), and the incidence of blackpoint. Only N concentration and blackpoint were affected significantly by treatments in 2012. Rain shelter throughout grain filling reduced N concentration, whereas rain shelter reduced the incidence of blackpoint and ear wetting increased it. In 2011, rain shelter throughout reduced S concentration, increased N:S ratio and reduced SDS. Treatment effects on HFN were not consistent within or between years. Nevertheless, a comparison between the extreme treatment means in 2012 indicated damage from late rain combined with ear wetting resulted in a reduction of c. 0.7 s in HFN/mm August rainfall, whilst that between samples taken immediately after ear wetting at harvest maturity or 7 d later suggested recovery from damage to HFN upon re-drying in planta. Hence, the incidence of blackpoint was the only grain quality trait affected consistently by the diverse treatments. The remaining aspects of grain quality were comparatively resilient to rain incident upon developing and maturing ears of cvar Tybalt. No consistent temporal patterns of sensitivity to shelter or ear wetting were detected for any aspect of grain quality.
Resumo:
The objective of this study was to apply response surface methodology to estimate the emulsifying capacity and stability of mixtures containing isolated and textured soybean proteins combined with pectin and to evaluate if the extrusion process affects these interfacial properties. A simplex-centroid design was applied to the model emulsifying activity index (EAI), average droplet size (D-[4.3]) and creaming inhibition (Cl%) of the mixtures. All models were significant and able to explain more than 86% of the variation. The high predictive capacity of the models was also confirmed. The mean values for EAI, D-[4.3] and Cl% observed in all assays were 0.173 +/- 0.015 mn, 19.2 +/- 1.0 mu m and 53.3 +/- 2.6%, respectively. No synergism was observed between the three compounds. This result can be attributed to the low soybean protein solubility at pH 6.2 (<35%). Pectin was the most important variable for improving all responses. The emulsifying capacity of the mixture increased 41% after extrusion. Our results showed that pectin could substitute or improve the emulsifying properties of the soybean proteins and that the extrusion brings additional advantage to interfacial properties of this combination. (C) 2008 Elsevier Ltd. All rights reserved.
Resumo:
Effect of processing on the antioxidant activity of amaranth grain. Amaranth has attracted increasing interest over recent decades because of its nutritional, functional and agricultural characteristics. Amaranth grain can be cooked, popped, toasted, extruded or milled for consumption. This study investigated the effect of these processes on the antioxidant activity of amaranth grain. Total phenolic content and in vitro antioxidant activity were determined according to two methods: inhibition, of lipid oxidation using the beta-carotene/linoleic acid system and the antioxidant activity index using the Rancimat (R) apparatus. The processing reduced the mean total phenolics content in amaranth grain from 31.7 to 22.0 mg of gallic acid equivalent/g of dry residue. It was observed that the ethanol extract from toasted grain was the only one that presented a lower antioxidant activity index compared with the raw grain (1.3 versus 1.7). The extrusion, toasting and popping processes did not change the capacity to inhibit amaranth lipid oxidation (55%). However, cooking increased the inhibition of lipid oxidation (79%), perhaps because of the longer time at high temperatures in this process (100 degrees C/10 min). The most common methods for processing amaranth grain caused reductions in the total phenolics content, although the antioxidant activity of popped and extruded grain, evaluated by the two methods, was similar to that of the raw grain. Both raw and processed amaranth grain presents antioxidant potential. Polyphenols, anthocyanins, flavonoids, tocopherols, vitamin C levels and Maillard reaction products may be related to the antioxidant activity of this grain.
Resumo:
Soybean oil can be deacidified by liquid-liquid extraction with ethanol. In the present paper, the liquid-liquid equilibria of systems composed of refined soybean oil, commercial linoleic acid, ethanol and water were investigated at 298.2 K. The experimental data set obtained from the present study (at 298.2 K) and the results of Mohsen-Nia et al. [1] (at 303.2 K) and Rodrigues et al. [2] (at 323.2 K) were correlated by applying the non-random two liquid (NRTL) model. The results of the present study indicated that the mutual solubility of the compounds decreased with an increase in the water content of the solvent and a decrease in the temperature of the solution. Among variables, the water content of the solvent had the strongest effect on the solubility of the components. The maximum deviation and average variance between the experimental and calculated compositions were 1.60% and 0.89%, indicating that the model could accurately predict the behavior of the compounds at different temperatures and degrees of hydration. (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
The aim of this work was to encapsulate casein hydrolysate by spray drying with soybean protein isolate (SPI) as wall material to attenuate the bitter taste of that product. Two treatments were prepared: both with 12 g/100 g solids and containing either two proportions of SPI: hydrolysate (70:30 and 80:20), called M1 and M2, respectively. The samples were evaluated for morphological characteristics (SEM), particle size, hygroscopicity, solubility, hydrophobicity, thermal behavior and bitter taste with a trained sensory panel using a paired-comparison test (non-encapsulated samples vs. encapsulated samples). Microcapsules had a continuous wall, many concavities, and no porosity. Treatments M1 and M2 presented average particle sizes of 11.32 and 9.18 mu m, respectively. The wall material and/or the microencapsulation raised the hygroscopicity of the hydrolysate since the free hydrolysate had hygroscopicity of 53 g of water/100 g of solids and M1 and M2 had 106.99 and 102.19 g of water/100 g of solids, respectively. However, the hydrophobicity decreases, the absence of a peak in encapsulated hydrolysates, and the results of the panel sensory test considering the encapsulated samples less bitter (p < 0.05) than the non-encapsulated, showed that spray drying with SPI was an efficient method for microencapsulation and attenuation of the bitter taste of the casein hydrolysate. (c) 2008 Elsevier Ltd. All rights reserved.
Resumo:
The main goal of this work was to evaluate thermodynamic parameters of the soybean oil extraction process using ethanol as solvent. The experimental treatments were as follows: aqueous solvents with water contents varying from 0 to 13% (mass basis) and extraction temperature varying from 50 to 100 degrees C. The distribution coefficients of oil at equilibrium have been used to calculate enthalpy, entropy and free energy changes. The results indicate that oil extraction process with ethanol is feasible and spontaneous, mainly under higher temperature. Also, the influence of water level in the solvent and temperature were analysed using the response surface methodology (RSM). It can be noted that the extraction yield was highly affected by both independent variables. A joint analysis of thermodynamic and RSM indicates the optimal level of solvent hydration and temperature to perform the extraction process.
Resumo:
Free fatty acids are known for playing a crucial role in the development of insulin resistance. High fat intake is known for impairing insulin sensitivity; however, the effect of vegetable-oil injections have never been investigated. The present study investigated the effects of daily subcutaneous injections (100 mu L) of soybean (SB) and sunflower (SF) oils, during 7 days. Both treated groups developed insulin resistance as assessed by insulin tolerance test. The mechanism underlying the SB- and SF-induced insulin resistance was shown to involve GLUT4. In SB- and SF-treated animals, the GLUT4 protein expression was reduced similar to 20% and 10 min after an acute it? vivo stimulus with insulin, the plasma membrane GLUT4 content was similar to 60% lower in white adipose tissue (WAT). No effects were observed in skeletal muscle. Additionally, both oil treatments increased mainly the content of palmitic acid (similar to 150%) in WAT, which can contribute to explain the GLUT4 regulations. Altogether, the present study collects evidence that those oil treatments might generate insulin resistance by targeting GLUT4 expression and translocation specifically in WAT. These alterations are likely to be caused due to the specific local increase in saturated fatty acids that occurred as a consequence of oil daily injections. Copyright (C) 2010 John Wiley & Sons, Ltd.
Resumo:
Magnetic properties of nanocrystalline NiFe(2)O(4) spinel mechanically processed for 350 h have been studied using temperature dependent from both zero-field and in-field (57)Fe Mossbauer spectrometry and magnetization measurements. The hyperfine structure allows us to distinguish two main magnetic contributions: one attributed to the crystalline grain core, which has magnetic properties similar to the NiFe(2)O(4) spinel-like structure (n-NiFe(2)O(4)) and the other one due to the disordered grain boundary region, which presents topological and chemical disorder features(d-NiFe(2)O(4)). Mossbauer spectrometry determines a large fraction for the d-NiFe(2)O(4) region(62% of total area) and also suggests a speromagnet-like structure for it. Under applied magnetic field, the n-NiFe(2)O(4) spins are canted with angle dependent on the applied field magnitude. Mossbauer data also show that even under 120 kOe no magnetic saturation is observed for the two magnetic phases. In addition, the hysteresis loops, recorded for scan field of 50 kOe, are shifted in both field and magnetization axes, for temperatures below about 50 K. The hysteresis loop shifts may be due to two main contributions: the exchange bias field at the d-NiFe(2)O(4)/n-NiFe(2)O(4) interfaces and the minor loop effect caused by a high magnetic anisotropy of the d-NiFe(2)O(4) phase. It has also been shown that the spin configuration of the spin-glass like phase is modified by the consecutive field cycles, consequently the n-NiFe(2)O(4)/d-NiFe(2)O(4) magnetic interaction is also affected in this process. (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
Dielectric properties of BaTiO(3) ferroelectric ceramics were studied over wide frequency and temperature ranges. The materials showed complex dielectric behaviors, which included an anomalous increase of permittivity towards higher temperatures. Important, this property tended however to saturate to values that varied with grain-boundary density. Application of impedance spectroscopy and consideration of the series-layer model allowed a coherent discussion of these and other interesting observations from this work. In particular, analysis of the relationship existing in this model between macroscopic and microscopic dielectric properties rendered possible to account for grain vs. grain-boundary dielectric behaviors, in harmony with microstructure features, and to know the dielectric anomaly strength to be in fact expected from grain boundaries in such polycrystalline materials. (C) 2010 Elsevier Ltd. All rights reserved.
Resumo:
SBTX, a novel toxin from soybean, was purified by ammonium sulfate fractionation followed by chromatographic steps DEAE-Cellulose, CM-Sepharose and Superdex 200 HR fast-protein liquid chromatography (FPLC). Lethality of SBTX to mice (LD50 5.6 mg/kg) was used as parameter in the purification steps. SBTX is a 44-kDa basic glycoprotein composed of two polypeptide chains (27 and 17 kDa) linked by a disulfide bond. The N-terminal sequences of the 44 and 27 kDa chains were identical (ADPTFGFTPLGLSEKANLQIMKAYD), differing from that of 17 kDa (PNPKVFFDMTIGGQSAGRIVMEEYA). SBTX contains high levels of Glx, Ala, Asx, Gly and Lys and showed maximum absorption at 280 nm, epsilon(1 cm) (1%) of 6.3, and fluorescence emission in the 290-450nm range upon excitation at 280nm. The secondary structure content was 35% alpha-helix, 13% beta-strand and beta-sheet, 27% beta-turn, 25% unordered, and 1% aromatic residues. Immunological assays showed that SBTX was related to other toxic proteins, such as soyatoxin and canatoxin, and cross-reacted weekly with soybean trypsin inhibitor and agglutinin, but it was devoid of protease-inhibitory and hemagglutinating activities. The inhibitory effect of SBTX on growth of Cercospora sojina, fungus causing frogeye leaf spot in soybeans, was observed at 50 mu g/ml, concentration 112 times lesser than that found to be lethal to mice. This effect on phytopathogenic fungus is a potential attribute for the development of transgenic plants with enhanced resistance to pathogens. (c) 2007 Elsevier Ltd. All rights reserved.