Oxidative phosphorylation efficiency, proton conductance and reactive oxygen species production of liver mitochondria correlates with body mass in frogs

ody size is a central biological parameter affecting most biological processes (especially energetics) and mitochondria is a key organelle controlling metabolism and is also the cell's main source of chemical energy. However, the link between body size and mitochondrial function is still unclear, especially in ectotherms. In this study, we investigated several parameters of mitochondrial bioenergetics in the liver of three closely related species of frogs (the common frog Rana temporaria, the marsh frog Pelophylax ridibundus and the bull frog Lithobates catesbeiana). These particular species were chosen due to their differences in adult body mass. We found that the mitochondrial coupling efficiency was markedly increased with animal size, which lead to a higher ATP production (+70%) in the larger frogs (L. catesbeiana) compared to the smaller frogs (R. temporaria). This was essentially driven by a strong negative dependence of mitochondrial proton conductance on body mass. Liver mitochondria from the larger frogs (L. catesbeiana) displayed 50% of the proton conductance of mitochondria from the smaller frogs (R. temporaria). Contrary to our prediction, the low mitochondrial proton conductance measured in L. catesbeiana was not associated with higher radical oxygen species production. Instead, liver mitochondria from the larger individuals produced significantly lower radical oxygen species than those from the smaller frogs. Collectively, the data shows that key bioenergetics parameters of mitochondria (proton leak, ATP production efficiency and radical oxygen species production) are correlated with body mass in frogs. This research expands our understanding of the relationship between mitochondrial function and the evolution of allometric scaling in ectotherms

Improvement of accession distinctiveness as an added value to the global worth of the yam (Dioscorea spp) genebank

Open Access JournalMisidentification of accessions is a common problem in genebanks. Along the years, mistakes accumulate and this is particularly true when dealing with a large number of accessions requiring annual regeneration. Human errors such as mislabeling or misreading and material mix up during planting or storage are the main causes for misidentification of accessions. The international collection of yam, maintained at IITA, has accumulated ‘non true to type’ accessions along the years. In the present study, 53 morphological descriptors were used to detect uniformity of individuals within accessions of the yam gene bank collection i.e. agro morphological mismatch between individual plants of the same accession. Based on a similarity matrix, individual pairs with less than 0.90 similarity coefficients, which varies in six descriptors and more, were considered as distinct and mismatched, whereas those that had similarity coefficients greater than or equal to 0.90 were considered as clones from the same parent. Overall, 20.60% of the total 3156 accessions were found not true to type i.e., misidentified individuals. The descriptive analysis shows that morphological traits like distance between lobes, upward folding of leaf along main vein, young stem color, old stem color, leaf shape, leaf density and plant vigor are the most discriminative descriptors for individual identification within accession. Some other traits were also found species specific and they may aid in distinguishing misidentifications between species

Field collection, preservation and large scale DNA extraction procedures for cassava (Manihot esculenta Crantz.)

Some genetic studies using molecular methods such as diversity assessment or marker-assisted selection require collection of a large number of samples from fields located in the vicinity or in remote areas, followed by isolation of good quality DNA in a short time span. In the present study, different tissue preservation methods were compared for subsequent DNA extraction using a modified CTAB method in two 96-well plates, following grinding of leaf tissues with a GenoGrinder 2000. We found that preservation of leaf tissues in NaCl-CTAB-azide buffer (as described in Rogstad, 1992) at 4°C is a better storage procedure than preservation at -20°C to obtain good quality DNA. Comparison of DNA extraction with or without use of phenol revealed that the quality of DNA was not drastically affected when non-phenol extraction protocol was used and did not affect PCR amplification. Thus, the recommended DNA extraction procedure allowed us to process 192 samples per day at a cost of $0.80 per sample, with an average yield of 1.8  g, suitable for both PCR and genotyping

Seed Metrics for Genetic and Shape Determinations in African Yam Bean [Fabaceae] (Sphenostylis stenocarpa Hochst. Ex. A. Rich.) Harms

The metric measures on seeds, their correlation and relationship are important for systematic breeding for seed yield and shape determination. Variations among eighty genotypes of African yam bean (AYB) for six metric seed characters (seed length, width and thickness and their ratios) were evaluated in this study. Paired comparison among the six characters revealed very high significance (P < 0.001), approving the six traits as unique parameters for evaluating AYB. They equally exhibited high and substantial genetic variance: the genotypic proportion of the total variation ranged between 90 and 97%, broad sense heritability (81 - 94%) and genetic advances (14 - 31%). Seed length and width had the highest joint inheritance of 99.04%, the least, 4.32% was between width and WT as depicted by coheritability. Positive and significant (P < 0.05) phenotypic and/or genotypic correlation existed between seed width and thickness, the three ratios and seed length with the ratios except WT. Non-significant negative correlation existed between seed thickness with LT and WT. There were very reliable and highly significant linear relationships between the seed traits except for length and width whose relationship was non-linear. Breeding concentration on any of these traits may simultaneously influence the others. The seed shape indices were the metric ratios and the flatness index; they described the common shapes of AYB seeds as: round/spherical, oval/ellipsoidal, oblong and rhomboi

Cost Effectiveness of Germplasm Collections in the CG System. Section 9

Cost information is useful to monitor the performance of the genebanks. Thus, managers, users, and donors of the genebanks can have an idea of the relative costs of managing plant genetic resources. This information can be used to make users but especially donors aware of the actual costs of conserving and distributing accessions and in this way facilitate fund raising. Managers however do have an idea of genebank operational costs. What is then the added value of using a periodic system to collect costs information for the genebank manager? In this section we present some specific cases where the information collected in the genebanks visited can help in the decision process. It is true that the current amount of information does not allow us to make conclusions across centers, but it does allow for some analysis within the centers....

Effect of various sugars desiccation and freezing

Abstract During a 7-day conditioning treatment of clumps of oil palm (Elaeis guineensis Jacq.) somatic embryos on a medium containing 0.75 M sucrose, the fructose and glucose concentrations remained constant, whereas a ten-fold and twenty-fold increase were noted for sucrose and starch concentrations, respectively. The only new sugar detected was arabinose which remained a t a low concentration. After conditioning on media supplemented with various sugars and polyols at similar osmolarities, recovery of clumps of embryo growth was satisfactory except with ribose. After a n additional desiccation period, survival was optimal with fructose, galactose, sucrose and glucose, intermediate with maltose and lower with other compounds. When embryos were cryopreserved without previous desiccation, survival was noted after conditioning treatment with sucrose only. In contrast, when freezing was performed after dehydration, survival could b e obtained with several substances. It w a s optimal with sucrose, fructose, galactose and raffinose but w a s possible also with sorbitol and glucose. Intensity of recovery of proliferation was highest with embryos conditioned with sucrose

Refinement and standardization of storage procedures for clonal crops. Global Public Goods Phase 2: Part 1. Project landscape and general status of clonal crop in vitro conservation technologies

Among the collective actions of the World Bank-funded Global Public Goods Phase II Project (GPG2), the following collaborative activity: “Refinement and standardization of storage procedures for clonal crops” was given to the CGIAR’s In Vitro Genebanks, represented by the Clonal Crop Task Force (CCTF) composed of genetic resources research staff from the four centres: Bioversity International, CIAT, CIP and IITA. These hold the in trust collections of Musa, cassava, potato, sweetpotato, yam and Andean root and tuber crops (ARTCs). The overarching aims of this activity were to: (1) review the status of vitro conservation in the context of the GPG2 project with an emphasis on the mandated clonal crops; (2) survey the facilities, storage protocols and practices of CGIAR’s clonal crop genebanks; (3) collate and review this information with a view to developing quality and risk management systems to support the production and validation of multi-crop best practice guidelines. Outputs from this activity are designated as a three part ‘trilogy’: Part I, entitled “Project landscape and general status of clonal crop in vitro conservation technologies” introduces the GPG2 project within the CGIAR landscape and overviews the status of in vitro plant conservation in the wider conservation community of practice. This part describes the role of risk and quality management for the effective maintenance of in vitro genebanks in the context of research and the development and validation of best practices

Refinement and standardization of storage procedures for clonal crops. Global Public Goods Phase 2. Part 3: Multi-crop guidelines for developing in vitro conservation best practices for clonal crops

Among the collective actions of the World Bank-funded Global Public Goods Phase II Project (GPG2), the following collaborative activity: “Refinement and standardization of storage procedures for clonal crops” was given to the CGIAR’s In Vitro Genebanks, represented by the Clonal Crop Task Force (CCTF) composed of genetic resources research staff from the four centres: Bioversity International, CIAT, CIP and IITA. These hold the in trust collections of Musa, cassava, potato, sweetpotato, yam and Andean root and tuber crops (ARTCs). The overarching aims of this activity were to: (1) review the status of vitro conservation in the context of the GPG2 project with an emphasis on the mandated clonal crops; (2) survey the facilities, storage protocols and practices of CGIAR’s clonal crop genebanks; (3) collate and review this information with a view to developing quality and risk management systems to support the production and validation of multi-crop best practice guidelines. Outputs from this activity are designated as a three part ‘trilogy’: Part III, “Multi-crop guidelines for developing in vitro conservation best practices for clonal crops” is a compilation of quality and risk management best practices and guidelines from both plant and other bioresources communities. This collective knowledge provided the foundation for developing the GPG2 multi-crop best practice guidelines. They are compiled in two parts. Section I comprises general operational guidelines for quality and risk management in in vitro plant genebanks. Section II provides generic, multi-crop technical guidelines for the medium-term (slow growth) and long-term (cryopreservation) storage of crop germplasm held in In vitro active genebanks (IVAGs) and In vitro base genebanks (IVBGs) respectively

Refinement and standardization of storage procedures for clonal crops. Global Public Goods Phase 2. Part 2: Status of in vitro conservation technologies for: Andean root and tuber crops, cassava, Musa, potato, sweetpotato and yam

Among the collective actions of the World Bank-funded Global Public Goods Phase II Project (GPG2), the following collaborative activity: “Refinement and standardization of storage procedures for clonal crops” was given to the CGIAR’s In Vitro Genebanks, represented by the Clonal Crop Task Force (CCTF) composed of genetic resources research staff from the four centres: Bioversity International, CIAT, CIP and IITA. These hold the in trust collections of Musa, cassava, potato, sweetpotato, yam and Andean root and tuber crops (ARTCs). The overarching aims of this activity were to: (1) review the status of vitro conservation in the context of the GPG2 project with an emphasis on the mandated clonal crops; (2) survey the facilities, storage protocols and practices of CGIAR’s clonal crop genebanks; (3) collate and review this information with a view to developing quality and risk management systems to support the production and validation of multi-crop best practice guidelines. Outputs from this activity are designated as a three part ‘trilogy’: Part II, “Status of in vitro conservation technologies for Andean root and tuber crops, cassava, Musa, potato, sweetpotato and yam” provides a status update on the mandate clonal crops. As tasked by GPG2, it includes lessons learnt, critical point analyses and the priority research needs of CGIAR’s in vitro genebanks