Copper Biosorption by Biomass of Marine Alga: Study of Equilibrium and Kinetics in Batch System and Adsorption/Desorption Cycles in Fixed Bed Column     

Márcia Regina Fagundes-Klen  Márcia Teresinha Veit  Carlos Eduardo Borba  Rosangela Bergamasco  Luiz Gustavo de Lima Vaz  Edson Antonio da Silva 《Water, air, and soil pollution》2010,213(1-4):15-26

Copper biosorption onto chemically modified biomass of marine alga Sargassum filipendula was investigated in a batch reactor and a fixed bed column. Experiments were carried out in the batch reactor to obtain kinetic and equilibrium data and to assess the copper desorption efficiency of different eluent solutions. The pseudo-first-order, pseudo-second-order, and Langmuir kinetic models were used to correlate kinetic data. The experimental data fitted well to the pseudo first order and Langmuir kinetic models. Langmuir and Freundlich models were applied to describe the equilibrium data obtained at a fixed temperature of 30°C and at pH values of 3.0, 4.0, 5.0, and 6.0. The maximum capacities of copper biosorption onto the algal biomass were 1.43, 1.59, 2.40, and 2.36 mequiv./g at pH 3.0, 4.0, 5.0, and 6.0, respectively. The efficiencies of two eluent solutions (calcium chloride and hydrochloric acid) for copper removal from the biomass were evaluated at different concentrations (0.1, 0.2, 0.5, and 1.0 mol/L). The efficiencies of the calcium chloride solutions varied from 1% to 14%, while efficiencies varying from 95% to 99% were obtained when hydrochloric acid solutions were applied. Three adsorption/desorption cycles were carried out in a fixed bed column using 0.1 mol/L hydrochloric acid as eluent solution. The results showed that an increase in the number of cycles led to a reduction in the adsorption capacity of the alga. The desorbed copper fraction presented no significant variation, remaining around 63% in the three adsorption/desorption cycles.  相似文献   

Effect of Copper(II), Lead(II), and Zinc(II) on Growth and Sporulation of Halophytophthora from Taiwan Mangroves     

Eduardo M. Leaño  Ka-Lai Pang 《Water, air, and soil pollution》2010,213(1-4):85-93

This study evaluated the effect of lead (Pb(II)), zinc (Zn(II)) and copper (Cu(II)) on growth and sporulation of four Halophytophthora species (Halophytophthora vesicula, Halophytophthora elongata, Halophytophthora spinosa var. lobata, and an oogonia-producing Halophytophthora sp.) isolated from different mangrove sites in Taiwan. Results show that all isolates grew well or even better at 1 ppm concentration of the heavy metals tested. Growth of all test isolates was totally inhibited at 500 ppm, except for H. spinosa var. lobata exposed to Zn(II). For sporulation, all isolates produced moderate to abundant zoosporangia or oogonia at 1 ppm Pb(II) and Zn(II). Production of zoosporangia by H. vesicula, H. elongata and H. spinosa var. lobata was significantly affected or totally inhibited at 1 ppm Pb(II) and Zn(II) and all concentrations of Cu(II). Abnormal oogonia were produced by Halophytophthora sp. at 10 ppm Cu(II) and 100 ppm of the three heavy metals. In general, Cu(II) and Zn(II) were found to be the most toxic, and the least toxic was Pb(II). H. spinosa var. lobata was the most tolerant to all the heavy metals, while H. vesicula and H. elongata were the most sensitive. Results of this study shows that increased concentrations of Pb(II), Cu(II), and Zn(II) in the mangrove environment can significantly affect growth and impair normal reproduction of Halophytophthora species.  相似文献   

Consequences of a large-scale fragmentation experiment for Neotropical bats: disentangling the relative importance of local and landscape-scale effects     

Ricardo Rocha  Milou Groenenberg  Paulo E. D. Bobrowiec  Mar Cabeza  Jorge M. Palmeirim  Christoph F. J. Meyer 《Landscape Ecology》2017,32(1):31-45

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Regulation of growth, fatty acid composition and delta 6 desaturase expression by dietary lipids in gilthead seabream larvae (Sparus aurata)     

Izquierdo MS  Robaina L  Juárez-Carrillo E  Oliva V  Hernández-Cruz CM  Afonso JM 《Fish physiology and biochemistry》2008,34(2):117-127

The Δ6 and Δ5 desaturases and elongases show only very limited activity in marine fish, and little is known of the possibility of enhancing Δ6 desaturase gene expression in these fish. The use of plant oils in marine fish diets is limited by their lack of n−3 highly unsaturated fatty acids (HUFA) despite an abundant content of the 18C fatty acid precursor linoleic and α-linolenic acids. The objective of the present study was to determine the ability of larval gilthead seabream to utilize vegetable oils and assess the nutritional regulation of Δ6 desaturase gene expression. Seventeen-day-old gilthead seabream larvae were fed during a 17-day period with one of four different microdiets formulated with either sardine fish oil (FO), soybean, rapeseed or linseed oils, respectively, or a fifth diet containing defatted squid meal and linseed oil. Good larval survival and growth, both in terms of total length and body weight, were obtained by feeding the larvae either rapeseed, soybean or linseed oils. The presence of vegetable oils in the diet increased the levels of 20:2n−9 and 20:2n−6, 18:2n−9, 18:3n−6, 20:3n−6 and 20:4n−6, in larvae fed rapeseed and soybean oils in comparison to those fed FO. In addition, a sixfold increase in the relative expression of Δ6 desaturase-like gene was found in larvae fed rapeseed and soybean oils, denoting the nutritional regulation of desaturase activity through its gene expression in this fish species. However, feeding linseed oil did not increase the expression of the Δ6 desaturase gene to such a high extent.  相似文献   

Trawling for cephalopods off the Portuguese coast—Fleet dynamics and landings composition   总被引：1，自引：0，他引：1  

Tereza Fonseca  Aida Campos  Manuel Afonso-Dias  Paulo Fonseca  Joo Pereira 《Fisheries Research》2008,92(2-3):180-188

Fleet dynamics was addressed for three cephalopod taxa of commercial interest, the squid Loligo vulgaris, the octopuses Octopus vulgaris and Eledone cirrhosa, and the cuttlefish Sepia officinalis, for 48 trawlers of the fish trawling fleet. Landing profiles (LP) were identified based on the species composition of the landings using hierarchical cluster analysis. Four out of a total of 12 different LP were related to cephalopods and other species associated with them.The effects on the landing proportions of a number of variables, year, season and vessel, are analysed for each of the species studied using generalized linear models (GLM). The factor “vessel”, including an ensemble of technical characteristics as well as the abilities of individual skippers, explained most of the model deviance, strongly reinforcing the existence of a fleet component dedicated to catch cephalopods. However, time also explains much of the variation found in the data.Seasonal alternation between landings of octopodidae and cuttlefish was observed within a small group of old trawlers operating mainly off the south coast, following the abundance cycles of these species. For a larger group of more modern trawlers, operating off the western coast, inter-annual shift between octopus and squid was found, together with a well marked seasonal pattern between the catches of cephalopods and horse mackerel.Spatial patterns of activity were identified using vessel monitoring system (VMS) data available for trawlers in Portugal, demonstrating the existence of cephalopod targeting strategies in Portuguese fish trawling activities.  相似文献   

Evaluation of the efficacy of prophylactic hoof health examination and trimming during midlactation in reducing the incidence of lameness during late lactation in dairy cows     

Hernandez JA  Garbarino EJ  Shearer JK  Risco CA  Thatcher WW 《Journal of the American Veterinary Medical Association》2007,230(1):89-93

OBJECTIVE: To assess the efficacy of prophylactic hoof health examination and trimming during midlactation at reducing the incidence of lameness during late lactation in dairy cows. DESIGN: Randomized field trial. ANIMALS: 333 Holstein cows. PROCEDURES: Cows without apparent lameness were randomly allocated into 1 of 2 groups approximately 204 days after calving. Cows allocated to the treatment group (n = 161) were examined on a tilt table for diagnosis and underwent hoof-trimming procedures, if needed, for treatment of hoof disorders or lesions. Cows in the control group (n = 172) were not examined. Cows were assigned a locomotion score weekly for 28 weeks after allocation to a group. The number of cows classified as lame during late lactation (approx 205 to 400 days after calving) was compared between groups to assess the efficacy of prophylactic examination and trimming. RESULTS: Incidence of lameness during late lactation was 24% in cows in the control group and 18% in cows in the treatment group. CONCLUSIONS AND CLINICAL RELEVANCE: The 25% decrease in number of new cases of lameness in cows undergoing prophylactic hoof health examination and trimming during midlactation may be relevant for the well-being of dairy cows and should not represent a major economic burden to producers.  相似文献   

Effects of remifentanil infusion regimens on cardiovascular function and responses to noxious stimulation in propofol-anesthetized cats     

Correa Mdo A  Aguiar AJ  Neto FJ  Mendes Gda M  Steagall PV  Lima AF 《American journal of veterinary research》2007,68(9):932-940

OBJECTIVE: To evaluate the effects of 2 remifentanil infusion regimens on cardiovascular function and responses to nociceptive stimulation in propofol-anesthetized cats. ANIMALS: 8 adult cats. PROCEDURES: On 2 occasions, cats received acepromazine followed by propofol (6 mg/kg then 0.3 mg/kg/min, i.v.) and a constant rate infusion (CRI) of remifentanil (0.2 or 0.3 microg/kg/ min, i.v.) for 90 minutes and underwent mechanical ventilation (phase I). After recording physiologic variables, an electrical stimulus (50 V; 50 Hz; 10 milliseconds) was applied to a forelimb to assess motor responses to nociceptive stimulation. After an interval (> or = 10 days), the same cats were anesthetized via administration of acepromazine and a similar infusion regimen of propofol; the remifentanil infusion rate adjustments that were required to inhibit cardiovascular responses to ovariohysterectomy were recorded (phase II). RESULTS: In phase I, heart rate and arterial pressure did not differ between remifentanil-treated groups. From 30 to 90 minutes, cats receiving 0.3 microg of remifentanil/kg/min had no response to noxious stimulation. Purposeful movement was detected more frequently in cats receiving 0.2 microg of remifentanil/kg/min. In phase II, the highest dosage (mean +/- SEM) of remifentanil that prevented cardiovascular responses was 0.23 +/- 0.01 microg/kg/min. For all experiments, mean time from infusion cessation until standing ranged from 115 to 140 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Although the lower infusion rate of remifentanil allowed ovariohysterectomy to be performed, a CRI of 0.3 microg/kg/min was necessary to prevent motor response to electrical stimulation in propofol-anesthetized cats. Recovery from anesthesia was prolonged with this technique.  相似文献   

A rapid, seedling-based bioassay for identifying low cadmium-accumulating individuals of Durum wheat (Triticum turgidum L.).     

Daniel J. Archambault  Eduardo Marentes  Wayne Buckley  John Clarke  Gregory J. Taylor 《Euphytica》2001,117(2):175-182

We have developed a seedling-based bioassay that iscapable of identifying low Cd-accumulating phenotypes(homozygous and heterozygous) after 96–120 h ofexposure. Our experiments were conducted using¹⁰⁹Cd as a tracer at subtoxic concentrations tosimulate conditions that might be experienced in thefield. Supply of Cd (10^-11 M) to 4-d oldseedlings for 0–8 h resulted in no differences in rootand leaf Cd content between the low (TL05) and high(TL04) Cd-accumulating isolines. Increasing time ofexposure produced significant differences in leaf Cdaccumulation between isolines, with differencesbecoming most pronounced after the bulk of appliedcadmium ( 95%) was depleted from absorption solutions( 72 h). Similar results were obtained with8-d old seedlings, where differences between genotypeswere more pronounced in young leaves (2nd leaf) orshoot bases. Individuals from five low and highCd-accumulating near isogenic pairs (50individuals/isoline) were screened using Cdconcentration of shoot bases as the screeningcriterion. Mean scores within each isoline pair weresignificantly different, although overlap ofindividual scores was observed at intermediate foliarCd concentrations. The 2^nd leaf to root Cdcontent ratio, which reflects root to shoottranslocation, provided a better parameter todistinguish low from high Cd-accumulating isolines. Plants used for this bioassay could also be rescuedfor subsequent experimental crosses, providing a rapidand cost-effective tool for early detection of the lowCd-accumulating phenotype.  相似文献   

Assessment of genetic relatedness of the genera Ananas and Pseudananas confirmed by RAPD markers     

Claudete de Fátima Ruas  Paulo Maurício Ruas  José Renato S. Cabral 《Euphytica》2001,119(3):245-252

Genetic relationships among 18 accessions, including 16 of Ananas and two of Pseudananas, were investigated using RAPD molecular markers. The procedure for DNA extraction was adapted from the method of Dellaporta et al. (1983) where an incubation in proteinase K and a purification step were included. From the total of 148 markers scored,132 (89.2%) were polymorphic. The similarity matrix was used for cluster analysis. The phenogram developed from the RAPD bands showed that for most of the cases, the accessions within a species grouped together. Nevertheless, a moderate infraspecific genetic variation was observed. For example, DNA data grouped all A. comosus accessions with a mean similarity coefficient of 0.85. Comparable results were obtained with all other species investigated. The highest genetic divergence was found withinA. lucidus where the mean similarity coefficient among accessions was0.75. A similar level of genetic polymorphism was observed among species,therefore, a definition about which species were involved in the constitution of A. comosus genotypes was not possible. These results agree with the breeders standpoint suggesting that all Ananas species belong to the primary gene pool of pineapple. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Effect of Ogura male-sterile cytoplasm on the performance of cabbage hybrid variety. II. Commercial characteristics     

Paulo E. de Melo  Leonardo B. de Giordano 《Euphytica》1994,78(1-2):149-154

Summary The main constraint of using Ogura male-sterile cytoplasm in Brassica is the induction of leaf yellowing at low temperature and the low seed set. But whether or not the cytoplasm can disturb the general commerical performance of the plants is not well-known. Therefore, this work was carried out with the purpose of evaluating Ogura cytoplasmic male-sterile cabbage hybrids and compare them to genomic similar male-fertile ones and to the most popular cabbage hybrid cultivated in Brazil. Harvest data showed an effect of the cytoplasm on reducing plant and head weight, core length and head length and width, although not altering heading index, shape and core indexes, nor head compactness. On the other hand, it was observed also that a careful selection of the parental lineages can produce male-sterile hybrids as good as their male-fertile analogues. All the evaluated hybrids were similar or better than the check for the characteristics under study.Abbreviations dat - days after transplanting - CNPH - National Center for Vegetable Crops Research  相似文献