Incubation of embryos and larvae of marine fish using microtiter plates     

Elsa B. Panini  Constantinos C. Mylonas  Sylvia Zanuy  Manuel Carrillo  Jesus Ramos  Michael P. Bruce 《Aquaculture International》2001,9(2):189-196

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Performance of purebred and crossbred progeny of White Leghorn and New Hampshire sires     

M. Taran  Elsa Gabriel  E. Moses  M. Soller 《British poultry science》1972,13(4):331-339

Data from a reciprocal recurrent selection (RRS) programme involving a White Leghorn and a New Hampshire flock were analysed to determine whether there were genetic differences in the purebred population that came to expression primarily in the crossbred progeny. The RRS programme had been in use for four years. The White Leghorn flock had previously been the subject of long‐continued and intensive family selection. The New Hampshire flock was less highly selected. Egg number, egg weight and body weight were the primary traits under selection. Each year the programme involved about 10 sires and 80 females of each breed, and about 400 offspring of each type of cross.

The overall economic value of the crossbreds consistently exceeded the mid‐parent mean, the difference increased steadily during the RRS programme. Heritabilities of the various traits were higher when calculated on the basis of crossbred offspring than when calculated on the basis of purebred offspring. For egg production in the White Leghorns there was a fairly low correlation between purebred and crossbred offspring of the same male. For other traits in both breeds the correlation between purebred and crossbred offspring was moderately high. There was a significant interaction between males and breed of females for all traits and breeds, except for egg number in the New Hampshire. These results are consistent with the notion that there were genetic differences between the purebred males (particularly the White Leghorn males) that affected the production characteristics of their crossbred progeny differently than their purebred progeny.  相似文献   

Infectious disease. Elusive pathogen cornered at last     

Youngsteadt E 《Science (New York, N.Y.)》2008,319(5871):1747

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Broad-sense heritability in mixed models for grapevine initial selection trials     

Elsa Gonçalves  Isabel Carrasquinho  António St. Aubyn  Antero Martins 《Euphytica》2013,189(3):379-391

This work addresses to the genetic analysis and selection in populations where the whole genotypic value is transmitted through generations, using grapevine yield data as a case study. Several models were applied to different types of data sets. The individual and mean year yield and the balanced and unbalanced data resulting from various experimental designs (completely randomized, randomized complete block and row–column) were used. The aims of present work were to study: (1) the applicability of a generalised measure of broad-sense heritability to evaluate the success of the genotypic selection and compare it with the classical approach; and (2) the effect of different models on the accuracy and precision of the genotypic variance component and on the generalised broad-sense heritability estimates. The results showed that the computation of a measure of generalised broad-sense heritability is very feasible and useful for evaluating the efficiency of genotypic selection. In this study, 88 % of the fitted models did not comply with the standards for applying the classical concept of heritability. The differences between both the classical and generalised broad-sense heritability estimates increased with the complexity of the model. Higher broad-sense heritability estimates were consistently obtained with the mean years. The most accurate and precise estimates of the genetic parameters were obtained with the spatial models. Finally, the genotypic variance component of yield and the generalised broad-sense heritability were consistently significant for all grapevine varieties.  相似文献   

Effects of Drying Process on the Physicochemical Properties of Nopal Cladodes at Different Maturity Stages     

Contreras-Padilla M  Gutiérrez-Cortez E  Valderrama-Bravo Mdel C  Rojas-Molina I  Espinosa-Arbeláez DG  Suárez-Vargas R  Rodríguez-García ME 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(1):44-49

Chemical proximate analysis was done in order to determine the changes of nutritional characteristics of nopal powders from three different maturity stages 50, 100, and 150 days and obtained by three different drying processes: freeze dried, forced air oven, and tunnel. Results indicate that nopal powder obtained by the process of freeze dried retains higher contents of protein, soluble fiber, and fat than the other two processes. Also, freeze dried process had less effect on color hue variable. No changes were observed in insoluble fiber content, chroma and lightness with the three different drying processes. Furthermore, the soluble fibers decreased with the age of nopal while insoluble fibers and ash content shows an opposite trend. In addition, the luminosity and hue values did not show differences among the maturity stages studied. The high content of dietary fibers of nopal pad powder could to be an interesting source of these important components for human diets and also could be used in food, cosmetics and pharmaceutical industry.  相似文献   

RNAi‐based Bean golden mosaic virus‐resistant common bean (Embrapa 5.1) shows simple inheritance for both transgene and disease resistance     

Josias C. Faria  Paula A. M. R. Valdisser  Elsa O. P. L. Nogueira  Francisco J. L. Aragão 《Plant Breeding》2014,133(5):649-653

Bean golden mosaic virus (BGMV) is the causal agent of bean golden mosaic of common beans. A transgenic bean line that has been developed based on RNA interference to silence the BGMV rep gene showed immunity to the virus. Crosses were done between the transgenic line and six bean cultivars followed by four backcrosses to the commercial cultivars ‘Pérola’ and ‘BRS Pontal’. The transgene locus was consistently inherited from the crosses analysed in a Mendelian fashion in the segregating populations. The disease resistance reaction co‐inherited with the transgene. Nevertheless, the expression of disease resistance displayed a dosage effect phenomenon in the F₁ generation. The analysis of the homozygous near‐isogenic lines in field conditions, under high BGMV disease incidence, indicated that the transgenic lines were completely resistant. These results show the strength of the disease resistance obtained, the stability of the trait across generations and its usefulness in the management of a disease for which there is no reported Phaseolus germplasm with immunity.  相似文献   

Phoretic dispersal of the entomopathogenic nematode Heterorhabditis amazonensis by the beetle Calosoma granulatum     

Natalia Ramos Mertz  Elsa Judith Guevara Agudelo  Fernanda Soares Sales  Cristhiane Rohde  Alcides Moino Jr. 《Phytoparasitica》2014,42(2):179-187

Entomopathogenic nematodes (EPN) have limited ability to travel and need to adopt alternative strategies to reach hosts that are far away. They can attach themselves to an organism that acts only as a dispersal agent to transport the EPN to places that they cannot reach by themselves. The larval and adult stages of Calosoma granulatum (Coleoptera: Carabidae) beetle are important predators of caterpillars that live in the soil of Brazilian agricultural systems. The nematode Heterorhabditis amazonensis (Rhabditida: Heterorhabditidae) is a native of Brazil and plays a major role in the control of Spodoptera frugiperda (Lepidoptera: Noctuidae) caterpillars. This study assessed the ability of C. granulatum to carry and disperse H. amazonensis. The experimental arenas consisted of two types of containers with substrate connected by a plastic tube through which the insects could move freely. Only one of the containers received infective juveniles (IJ) and the other was used as the test container. We first used C. granulatum larvae and adults to evaluate the influence of different concentrations of IJs on phoretic behavior. Then different distances traveled by the adult beetle were tested to measure their effect on IJ transport. The results showed that C. granulatum is a good phoretic dispersal agent and the transport of IJs by the larvae is less influenced than transport by the adult, by a change in the IJ concentration. The distance traveled by the adult influences the number of EPN carried and the detection of phoresy even at greater distances (40 cm) indicates that C. granulatum is capable of transporting the EPN for distances greater than those evaluated.  相似文献   

Early recognition of graft compatibility in <Emphasis Type="Italic">Uapaca kirkiana</Emphasis> Müell Arg. clones,provenances and species     

Simon A. Mng’omba  Elsa S. du Toit  Festus K. Akinnifesi 《Agroforestry Systems》2008,74(2):173-183

Examination of callus micro-grafts in Uapaca kirkiana Müell Arg. was carried out with the objective of determining early signs of graft compatibility. Leaves from U. kirkiana, U. nitida and Jatropha curcas trees were used for callus induction. Two pieces of callus were co-cultured on Murashige and Skoog (MS) medium with different supplements. Co-cultured calli were embedded in paraffin wax and dissected. The specimens were stained in safranin and fast green before viewing under a light microscope. Results showed that MS medium with 0.1 mg l⁻¹ thidiazuron (TDZ) and 0.5 mg l⁻¹ naphthaleneacetic acid (NAA) or 1.0 mg l⁻¹ dichlorophenoxyacetic acid (2,4-D) and 0.5 mg l⁻¹ NAA was effective for callus induction. There were no necrotic layers at the unions within U. kirkiana clones and provenances, but a differential growth (irregularity) between U. kirkiana and U. nitida co-cultured calli. Phenol deposits were observed at the union interfaces of U. kirkiana combinations and were high on calli derived from mature trees. Phenol deposits were absent at the union of J. curcas heterografts. Necrotic layers developed at the unions of U. kirkiana and J. curcas micro-grafts and indicating an outright graft incompatibility. Accumulation of phenol deposits at the union interfaces inhibited graft compatibility in many U. kirkiana combinations. Callus fusion technique can be used to identify partners with an outright graft incompatibility, especially for distant related plant species.  相似文献   

Electric ultrafreezer (− 150 °C) as an alternative for zebrafish sperm cryopreservation and storage     

Patrícia Diogo  Gil Martins  Isa Quinzico  Rita Nogueira  Paulo J. Gavaia  Elsa Cabrita 《Fish physiology and biochemistry》2018,44(6):1443-1455

Zebrafish sperm cryopreservation is a fundamental methodology to manage and back-up valuable genetic resources like transgenic and mutant strains. Cryopreservation usually requires liquid nitrogen for storage, which is expensive and hazardous. Our objective was to evaluate if electric ultrafreezers (??150 °C) are a viable alternative for zebrafish sperm storage. Zebrafish sperm was cryopreserved in the same conditions (??20 °C/min), stored either in liquid nitrogen or in an ultrafreezer, and thawed after 1 week, 1 month, and 3 months. Sperm motility, membrane integrity, and fertilization ability were assessed. There were no significant differences in motility and hatching rate throughout storage time. Additionally, we aimed at understanding if cryopreservation directly in an ultrafreezer (??66 °C/min) could improve post-thaw sperm quality. Freezing at ??20 °C/min was performed as before, and compared to samples cryopreserved with a fast cooling rate by placing directly in an ultrafreezer (??66 °C/min). Sperm quality was assessed according to motility, viability, DNA fragmentation, and apoptosis (annexin V). The ??66 °C/min cooling rate showed significantly higher membrane and DNA integrity, and lower number of cells in late apoptosis in comparison to the other treatments. This study showed that zebrafish sperm cryopreservation and storage in an ultrafreezer system is possible and a fast cooling rate directly in ultrafreezer improves post-thaw sperm quality.  相似文献   

Cytological mechanisms of 2n pollen formation in the wild potato Solanum okadae and pollen-pistil relations with the cultivated potato, Solanum tuberosum     

Elsa Lucila Camadro  Sandra Karina Saffarano  Juan Carlos Espinillo  Mateo Castro  Phillip W. Simon 《Genetic Resources and Crop Evolution》2008,55(3):471-477

Solanum okadae Hawkes et Hjert is a wild diploid potato species endemic to Argentina and Bolivia, of potential breeding value. However, no genetic studies have been carried out with this species and its crossability relations with the common tetraploid potato, S. tuberosum L. ssp. tuberosum, are unknown. Furthermore, accessions from both countries differed in their morphological phenotypes. To ascertain the feasibility of incorporating this wild germplasm into cultivated potato, 2n pollen screening was carried out in 10 accessions and families derived from crosses between accessions; also, pollen-pistil compatibility relations were studied in reciprocal interspecific crosses. Plants of four of the 10 accessions produced 2n pollen (0.1 to 5.0%) and 4n pollen (0.0 to 3.0%). Parallel and tripolar spindles at Anaphase II were the cytological mechanisms involved in 2n pollen formation; lack of chromosome migration in both meiotic divisions originated the 4n pollen. Both full compatibility and incompatibility at various sites along the pistil were observed in the S. tuberosum × S. okadae combinations; most reciprocal combinations were incompatible. Compatible genotypes produced 2n pollen. However, only a few seeds were obtained and chromosome counts could not be carried out in the hybrid progeny because seedlings died at an early stage. The pollen-pistil barriers are incomplete and can be circumvented by the appropiate choice of parents. The identification of the post-zygotic barriers will be the focus of further studies.  相似文献