Effects of foam fractionation and chemical disinfection on the removal of different microalgae cultures     

Mafalda Figueiras Guilherme  Kim Joo de Jesus Gregersen  Lars‐Flemming Pedersen 《Aquaculture Research》2020,51(8):3274-3283

The recent development of recirculation aquaculture systems (RAS) potentially allows more sustainable and controlled rearing conditions. However, control of suspended microparticles and microalgae in RAS is challenging, as uncontrolled blooms of toxic algae or heterotrophic dinoflagellates can have catastrophic impacts on the production of fish. In this study, we tested the potential of protein skimmers to remove microalgae. In 100 L batch tests, protein skimmers were tested separately and in combination with ozone (O₃), ultraviolet (UV) or hydrogen peroxide (H₂O₂). Three different and distinct microalgae cultures were tested with densities from 30,000 to 120,000 algae cells/ml in a triplicated experimental setup. Trial 1 included twelve 24‐hr replicated tests where protein skimmers with air or with two levels of ozone (low and high O₃ exposure) were compared. The protein skimmer with air alone had a limited effect on the removal of microalgae compared to the untreated control algae tanks. When ozone and protein skimmers were combined, a clear additive effect was found, and all added microalgae were removed. Low O₃ dosage and protein skimmers completely removed the algae cultures within 12 hr, while more than 95% of the algae were removed within 7 hr when a higher ozone dose was used. The second trial compared the removal capacity of protein skimmers in combination with UV, H₂O₂ and O₃. These experiments showed no to limited additive effect of UV combined with protein skimming, but significantly increased removal efficiency (270% and 1,300%, respectively) was found when H₂O₂ and ozone were combined with a protein skimmer. The study showed an algae species‐specific response to a protein skimmer with ozonation and provided information on the transition from reactivity and consumption to accumulation of ozone‐produced oxidants.  相似文献   

Development of deformities at the vertebral column in Diplodus sargus (L., 1758) early larval stages     

Margarida Saavedra  Lídia Nicolau  Pedro Pousão‐Ferreira 《Aquaculture Research》2010,41(7):1054-1063

One of the bottleneck problems of Diplodus sargus farming is a high incidence of skeletal deformities at the vertebral column. In this study, the pattern of vertebral deformities were determined in three different larval batches from 2 to 30 days after hatching (DAH). During this period, 60 larvae per spawn were observed at 2, 8, 13, 15, 18, 21, 23, 25, 27 and 30 DAH and the different types and frequency of vertebral column malformations were registered. Deformities started from 8 to 13 DAH, when the percentage of deformed larvae rose from approximately 5% to 40%. At 15 DAH, skeletal malformations had frequencies up to 80% of the observed larvae. Serious malformations such as kyphosis, scoliosis and lordosis were observed at 18 DAH but seldom in percentages higher than 15%. Vertebral fusions and compressions especially affected the preurostyle region. Abnormal shape vertebrae were more frequent between vertebrae 15 and 21. Other malformations observed were hypertrophic vertebrae, more common in the trunk and caudal regions, reaching percentages higher than 50% in the former. This study has useful information concerning skeletal malformations at the vertebral column of D. sargus larvae, as it identifies the main deformities observed and the ages of highest incidence.  相似文献   

Influence of temperature on muscle fibre hyperplasia and hypertrophy in larvae of blackspot seabream,Pagellus bogaraveo     

Paula Silva  Luísa Maria Pinheiro Valente  Mercedes Olmedo  Blanca Álvarez‐Blázquez  Maria Helena Galante  Rogério Alves Ferreira Monteiro  Eduardo Rocha 《Aquaculture Research》2011,42(3):331-340

The effects of temperature on Pagellus bogaraveo muscle cellularity were investigated, by morphometry, throughout the endogenous feeding stage, testing two rearing temperatures: 14 and 18 °C. The following parameters were estimated in transversal body sections at post‐opercular and post‐anal body levels: the total cross‐sectional muscle area, the total number of fibres and the mean cross‐sectional fibre area. At hatching, no significant influence of the temperature was observed on the morphometric parameters measured in the white muscle. At mouth opening, an increase in the number of post‐opercular white fibres was promoted by the highest temperature. During embryonic development, the red muscle fibre number in the post‐anal part of the larvae increased with higher temperature, but it appears that the difference was no longer present at mouth opening. An increase in the fibre area and in the total cross‐sectional area of red muscle at the post‐anal level was promoted by a 4 °C increase in the temperature during the vitelline phase. In conclusion, the axial musculature of blackspot seabream embryos/larvae reacted differently to temperature influence according to the body location, strongly supporting the need to look at and account for different body locations when evaluating muscle cellularity in fish, namely in growth/aquaculture‐related studies.  相似文献   

Seed germination and seedling vigour of transgenic tobacco (Nicotiana tabacum L.) with increased proline accumulation under osmotic stress     

Fabiana de Lima Abrantes  Alessandra Ferreira Ribas  Luiz Gonzaga Esteves Vieira  Nelson Barbosa Machado-Neto 《The Journal of Horticultural Science and Biotechnology》2019,94(2):220-228

Proline plays important roles in various stages and processes of plant development. However, there are few reports on the effect of endogenous proline accumulation on germination and seedling vigour under suitable conditions of germination and development. The aim of this work was to evaluate the effect of endogenous proline in transgenic tobacco (Nicotiana tabacum L.) constitutively expressing the VaP5CSF129A gene in germination and seedling vigour. Under optimal conditions of germination, the transgenic seeds had high proline content when compared to the non-transgenic plants. However, this higher accumulation did not result in better germination or seedling vigour, contrasting to reported results for exogenous proline application. The pre-treatment by water submersion indicated that the lowest initial seed germination with the highest proline concentration may be due to their greater post-harvest dormancy. When newly germinated seedlings were subjected to osmotic stress (?0.9 MPa), the free proline content increased proportionally in all genotypes and the transgenic events seedlings showed greater root length compared to those of the non-transformed control. This can be advantageous as, in theory, seedlings with longer roots may have a better chance of growing and exploring the different soil layers, allowing the transgenic events to be more tolerant to edaphic constraints.  相似文献   

Diversity of banana diploid hybrids: An assessment based on a hydroponic system     

Adriadna S. Santos  Edson P. Amorim  Alex-Alan F. Almeida  Claudia F. Ferreira  Mauricio Antonio Coelho Filho  Carlos P. Pirovani 《Plant Breeding》2020,139(6):1251-1265

Bananas are typical to tropical and subtropical climate regions, where they have better conditions due to high air humidity and soil water availability. The production of drought-tolerant varieties is an alternative to expand the cultivation sites to drier areas. In this work, we present a hydroponic system for the genotype selection of Musa sp. (AA) subjected to water stress. A total of 14 banana genotypes were tested; 12 diploids and two commercial varieties with a known response to drought tolerance. The results show that the improved diploids have different responses with respect to water deficit, with the PMGB043 and PMGB044 genotypes considered more susceptible and the PMGB075 and PMGB099 genotypes more tolerant. Under water deficit conditions, most banana diploids maintain a high relative water content, but there is a reduction in aerial part growth and an increase in root dry mass. The accumulation of alcohol dehydrogenase, especially in control treatment plants, indicate that the glycolytic pathway was used to supply energy demand, showing potential flood-tolerant genotypes. The results are essential for the preimprovement of banana cultivars.  相似文献   

Efficiency of low heritability QTL mapping under high SNP density     

José Marcelo Soriano Viana  Fabyano Fonseca e Silva  Gabriel Borges Mundim  Camila Ferreira Azevedo  Hikmat Ullah Jan 《Euphytica》2017,213(1):13

The efficiency of quantitative trait locus (QTL) mapping methods needs to be investigated assuming high single nucleotide polymorphism (SNP) density and low heritability QTLs. This study assessed the efficiency of the least squares, maximum likelihood, and Bayesian approaches for QTL mapping assuming high SNP density and low heritability QTLs. We simulated 50 samples of 400 F₂ individuals, which were genotyped for 1000 SNPs (average density of one SNP/centiMorgan) and phenotyped for three traits controlled by 12 QTLs and 88 minor genes. The genes were randomly distributed in the regions covered by the SNPs along ten chromosomes. The QTL heritabilities ranged from approximately 1–2% and the sample sizes were 200 and 400. The power of QTL detection ranged from 30 to 60%, the false discovery rate (FDR) ranged from only 0.5–1.2%, and the bias in the QTL position ranged from 4 to 6 cM. The QTL mapping efficiency was not influenced by the degree of dominance. The statistical approaches were comparable regarding the FDR. Regression-based and simple interval mapping methods showed equivalent power of QTL detection and mapping precision. Compared to interval mapping, the inclusive composite interval mapping provided slightly greater QTL detection power and mapping precision only for the intermediate and high heritability QTLs. By maximizing the prior number of QTLs, the Bayesian analysis provided the greatest power of QTL detection. No method proved to be superior.  相似文献   

Optimization of the Preparation Conditions of Yerba Mate tea Beverage to Maximize Chlorogenic Acids Extraction     

Tayse Ferreira Ferreira da Silveira  Adriana Dillenburg Meinhart  Thaís Cristina Lima de Souza  Elenice Carla Emídio Cunha  Maria Rosa de Moraes  José Teixeira Filho  Helena Teixeira Godoy 《Plant foods for human nutrition (Dordrecht, Netherlands)》2017,72(2):219-223

The beverage obtained from the yerba mate tea, besides being the most consumed in Brazil, has high concentrations of chlorogenic acids. In this study, a central composite design was employed to establish the best infusion time, temperature and water volume to maximize the extraction of chlorogenic acids 5-caffeoylquinic (5CQ), 3.4-dicaffeoylquinic (3.4 DQ), 3.5-dicaffeoylquinic (3.5 DQ) and 4.5-dicaffeoylquinic (4.5 DQ), from the leaves and stems of yerba mate tea (beverage ready for consumption). Analyses were performed by high-performance liquid chromatography and the optimum conditions were obtained through the use of the desirability function of Derringer and Suich. The maximum chlorogenic acids content in the beverage was obtained when the infusion was prepared with 2 g of mate tea, in 300 mL of water at 95 °C, under infusion for 16 min. The optimal conditions were applied for the preparation of beverages from 15 commercial samples of yerba mate tea, and it was observed that the sum of the concentration of the four compounds showed variation of up to 79 times between the average of the samples, which can be attributed to climatic conditions of cultivation of the plant and/or of processing.  相似文献   

Hierarchical spatial patterns and drivers of change in benthic macroinvertebrate communities in an intermittent Mediterranean river     

Samantha J. Hughes  Teresa Ferreira  Rui V. Cortes 《水产资源保护:海洋与淡水生态系统》2008,18(5):742-760

• 1. The imminent damming of the Odelouca River, an intermittent Mediterranean river situated in the south‐west Algarve region of Portugal with valuable stands of riparian vegetation, has called for the compulsory implementation of compensatory measures.
• 2. In order to assess the primary environmental and human factors that drive change in the benthic macroinvertebrate assemblages of the Odelouca, and the spatial scale at which they occur, 30 sites were sampled for benthic macroinvertebrates and extensively surveyed using River Habitat Survey (RHS) in spring 2005.
• 3. A hierarchical cluster analysis of selected physical and RHS variables clearly indicated gradients of habitat quality (instream and riparian corridor) along both main channel and tributaries. Analysis of macroinvertebrate metrics by parametric and non‐parametric ANOVA showed the derived clusters of groups to be biologically distinct.
• 4. From a total of 64 variables, divided into two explanatory variable groups (environmental or pressure) over three spatial scales (habitat, reach and basin), just 20, predominantly environmental, variables were retained for subsequent analyses.
• 5. Partial canonical correspondence analyses of the selected environmental and pressure variables over the defined spatial scales showed that environmental variables contributed most significantly over all of the spatial scales and that pressure variables related to land‐use only contributed significantly at the level of the river basin.
• 6. Variables recorded by RHS contribute successfully to the detection of habitat quality gradients in a Mediterranean river system and the strongest drivers of macroinvertebrate change are primarily, but not exclusively, environmental factors occurring at middle and higher spatial scales.
• 7. Compensatory measures must therefore be implemented across a range of spatial scales, taking into account abiotic and biotic processes characteristic of disturbance‐driven Mediterranean systems that contribute to habitat heterogeneity and quality and confer functional and trophic diversity to the macroinvertebrate assemblages.

Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Dry matter and area partitioning,radiation interception and radiation-use efficiency in open-field bell pepper     

M.I. Vieira  J.P. de Melo-Abreu  M.E. Ferreira  A.A. Monteiro 《Scientia Horticulturae》2009

The objective of this study was to determine some key components of a model for bell pepper growth and yield under non-limiting water and nutrient conditions using data from field trials conducted in Southern Portugal. DM partitioning, at least before fruiting, and specific area indices for leaves, stems and fruits were conservative in relation to normalized thermal time. The interception model had a good performance. It was based on the exponential extinction of radiation on the area covered by the plants, the ellipsoidal leaf-angle distribution model (X-parameter 2.48 and 2.89), and absorptivities of the leaves for PAR and NIR, 0.8 and 0.2, respectively. Radiation-use efficiency (RUE) was determined and presented in four different forms. RUE did not change substantially throughout the growing season. RUE of irrigated pepper crops grown in our experiments was around 1.6 g MJ⁻¹ of intercepted PAR. The models and parameter values presented in this study may be useful to simulate the development and growth of field-grown pepper crop.  相似文献   

The Effect of the Ionic Strength of Nutrient Solution on Gas Exchange,Ionic Concentration and Leaf Biomass of Annona emarginata (Schltdl.) H. Rainer Variety ‘Terra-Fria’ Seedlings     

D. Baron  G. Ferreira  C. S. F. Boaro  J. D. Rodrigues  A. C. E. Amaro  M. M. Mischan 《Journal of plant nutrition》2015,38(12):1944-1960

The present study aimed to test the hypothesis that different levels of the availability of mineral nutrients from Hoagland and Arnon's nutrient solution no. 2 affect the photosynthesis, ionic concentration and biomass production in seedlings of Annona emarginata (Schltdl.) H. Rainer variety ‘terra-fria’. Seedlings were grown in a hydroponic setting with 100% ionic strength and with ionic strength reduced to 75%, 50%, and 25%. Ionic strengths intermediate resulted in higher rates of carbon net assimilation and plants grown under these conditions increased biomass as well ionic concentrations of calcium, magnesium and sulfur. The ‘terra-fria’ plants with nutrient solutions of 50% and 75% ionic strength exhibited higher ionic concentrations, instantaneous carboxylation efficiency and biomass production. It can be concluded that the ‘terra-fria’ does not require the maximum mineral nutrients availability from Hoagland and Arnon's nutrient solution to achieve high primary productivity and intermediate ionic strengths can even reduce the time required for rootstock formation.  相似文献