The effects of light and temperature on the photosynthesis of the Asparagopsis armata tetrasporophyte (Falkenbergia rufolanosa), cultivated in tanks     

Leonardo Mata  João Silva  Andreas Schuenhoff  Rui Santos 《Aquaculture (Amsterdam, Netherlands)》2006,252(1):12-19

The integrated aquaculture of the tetrasporophyte of Asparagopsis armata Harvey (Falkenbergia rufolanosa) using fish farm effluents may be viable due to the species high capacity of removing nutrients and its content of halogenated organic compounds with applications on the pharmaceutical and chemical industries. In order to optimize the integrated aquaculture of F. rufolanosa, we followed the daily variation of the potential quantum yield (F_v/F_m) of PSII on plants cultivated at different biomass densities and different total ammonia nitrogen (TAN) fluxes to check if they are photoinhibited at any time of the day. Moreover, the photoinhibition under continuous exposure to highly saturating irradiance and its potential for subsequent recovery in the shade was assessed. The potential for year round cultivation was evaluated by measuring rates of O₂ evolution of plants acclimated at temperatures ranging from 15 to 29 °C, the temperature range of a fish farm effluent in southern Portugal where an integrated aquaculture system of F. rufolanosa was constructed.Photoinhibition does not seem to be a major constrain for the integrated aquaculture of F. rufolanosa. Only when cultivated at a very low density of 1.5 g fresh weight (FW) l^− 1 that there was a midday decrease in maximal quantum yield (F_v/F_m). At densities higher than 4 g FW l^− 1, no photoinhibition was observed. When exposed to full solar irradiance for 1 h, F. rufolanosa showed a 33% decrease in F_v/F_m, recovering to 86% of the initial value after 2 h in the shade. A midday decline of the F. rufolanosa F_v/F_m was also observed under the lowest TAN flux tested (∼6 μM h^− 1), suggesting that this fast and easy measurement of fluorescence may be used as a convenient diagnostic tool to detect nutrient-starved unbalance conditions of the cultures. Maximum net photosynthesis peaked at 15 °C with 9.7 mg O₂ g dry weight (DW)^− 1 h^− 1 and remained high until 24 °C. At 29 °C, the net oxygen production was significantly reduced due to a dramatic increase of respiration, suggesting this to be the species' lethal temperature threshold.Results indicate that F. rufolanosa has a considerable photosynthetic plasticity and confirm it as a good candidate for integrated aquaculture at temperatures up to 24° C and cultivation densities of at least 5 g FW l^− 1. When cultivated at these densities, light does not penetrate below the first few centimetres of the surface zone. Plants circulate within the tanks, spending around 10% of the time in the first few centimetres where they are able to use efficiently the saturating light levels without damaging their photosynthetic apparatus.  相似文献   

Efficacy of furunculosis vaccines in turbot, Scophthalmus maximus (L.): evaluation of immersion, oral and injection delivery     

Santos Y  García-Marquez S  Pereira PG  Pazos F  Riaza A  Silva R  El Morabit A  Ubeira FM 《Journal of fish diseases》2005,28(3):165-172

The commercial furunculosis vaccine Aquavac Furovac 5 and an autogenous vaccine, based on the challenge strain, induced immune protection in turbot, Scophthalmus maximus (L.), as shown in challenge tests 120 days post-immunization by injection (relative percentage of survival, RPS = 72-99%). This protective effect lasted for at least 6 months post-immunization at appreciable levels (RPS = 50-52%). Neither the autogenous vaccine nor the commercial vaccine was able to induce significant levels of protection against Aeromonas salmonicida in turbot when administered by immersion. Antibody levels were high or moderate in fish vaccinated by injection with the different vaccines and very low in fish vaccinated by immersion. The field results show that delivering an oral boost after the primary vaccination by injection did not enhance protection of turbot against furunculosis and that water-based (autogenous vaccine) and oil adjuvanted (Alpha Ject 1200) vaccines administered by injection conferred similar levels of protection (RPS > 80%) in turbot.  相似文献   

Size selectivity of the Spisula solida dredge in relation to tooth spacing and mesh size     

M. B. Gaspar  F. Leito  M. N. Santos  M. Sobral  L. Chícharo  A. Chícharo  C. C. Monteiro 《Fisheries Research》2003,60(2-3):561-568

A study was undertaken on the northwestern coast of Portugal to evaluate the selectivity effect of both tooth spacing and mesh size on the catch of the white clam (Spisula solida). Two typical clam dredges, equipped with different tooth spacing and mesh size, were towed side by side. Three tooth spacing (20, 40 and 60 mm) and three mesh sizes (35, 40 and 50 mm) were investigated. The dredge selectivity experiments were performed by attaching a cover bag with a 20 mm mesh to the gear. Individual hauls were analysed by the SELECT model. The Fryer’s mixed model of between-haul variation was also applied to data. The results showed that the space between teeth does not have an effect on selectivity. Tooth length was directly related to the dredge’s capture efficiency. The only factor that contributed to dredge size selection was mesh size. The 50% retention lengths estimated for mesh sizes 30, 40 and 50 mm were 25.68, 26.35 and 31.94 mm, respectively. For all mesh sizes, very narrow selection ranges were observed. The most appropriate mesh size to be enforced within the Portuguese northwestern S. solida fishery should be 40 mm.  相似文献   

Detection of Flexibacter maritimus in fish tissue using nested PCR amplification     

Cepeda C  García-Márquez S  Santos Y 《Journal of fish diseases》2003,26(2):65-70

A nested polymerase chain reaction (PCR) system was developed for the detection of Flexibacter maritimus from fish tissue. The total procedure for the diagnosis of marine flexibacteriosis, from the point of DNA extraction to the electrophoretic analysis, can be performed in < 4 h. This was achieved by the combination of a short thermal cycling programme with a rapid DNA extraction procedure. The assay was extremely sensitive, capable of detecting as few as 75 cfu mg(-1) fish tissue. The accuracy of the nested PCR was confirmed under field conditions using tissue samples recovered during 1993-2002 from fish suffering marine flexibacteriosis. The nested PCR method proved to be efficient for the rapid and sensitive detection of F. maritimus from fish tissues and can be used for routine diagnosis of the disease caused by this pathogen.  相似文献   

Dissolution Factors of Ta, Th, and U Oxides Present in Pyrochlore     

K. Dias da Cunha  M. Santos  F. Zouain  L. Carneiro  G. Pitassi  C. Lima  C. V. Barros Leite  K. C. P. Dália 《Water, air, and soil pollution》2010,205(1-4):251-257

Air pollution can be a problem in industrial processes, but monitoring and controling the aerosols in the work place is not enough to estimate the occupational risk due to dust particle inhalation. The solubility in lung fluid is considered to estimate this risk. The aim of this study is to determine in vitro specific dissolution parameters for thorium (Th), uranium (U), and tantalum (Ta) associated to crystal lattice of a niobium mineral (pyrochlore). Th, U, and Ta dissolution factors in vitro were obtained using the Gamble solution (simulant lung fluid, SLF), particle induced X-ray emission, and alpha spectrometry as analytical techniques. Ta, Th, and U are present in the pyrochlore crystal lattice as oxide; however, they have shown different dissolution parameters. The rapid dissolution fraction (f _r), rapid dissolution rate (λ _r), slow dissolution rate (f _s), and slow dissolution fraction (λ _s) measured for tantalum oxide were equal to 0.1 and 0.45 and 0.00007 day^?1, respectively. For uranium oxide, f _r was equal to 0.05, λ _r was equal to 1.1 day^?1, and λ _s was equal to 0.000068 day^?1. For thorium oxide, f _r was 0.025, λ _r was 1.5 day^?1, and λ _s was 0.000065 day^?1. These results show that chemical behavior of these three compounds in the SLF could not be represented by the same parameter. The ratio of uranium concentration in urine and feces samples from workers exposed to pyrochlore dust particle was determined. These values agree with the theoretical values of estimated uranium concentration using specific parameters for uranium oxide present in pyrochlore.  相似文献   

Tuberculosis survey of free-ranging marsh deer (Blastocerus dichotomus) in Brazil.     

Janaina O Luna  Manoel A A Santos  Edison L Durigon  Jo?o P Araújo Júnior  José M B Duarte 《Journal of zoo and wildlife medicine》2003,34(4):414-415

Esophageal-pharyngeal fluids from 53 free-ranging marsh deer (Blastocerus dichotomus) captured for a research program in the state of Mato Grosso do Sul, Brazil, were assayed for tuberculosis. Total DNA was extracted. amplified by polymerase chain reaction using specific primers for Mycobacterium tuberculosis complex (M. tuberculosis, M. bovis, M. microti, and M. africanum), and observed by agarose gel electrophoresis stained with ethidium bromide. All samples were negative. This, along with necropsy and histopathology data, suggests that these animals are not shedding and probably do not have active disease.  相似文献   

Host/parasite relationship in the in vitro infection of rat gliocytes by Neospora caninum: evaluation of cell respiration     

Pinheiro AM  Santos CV  Costa Mde F  Rodrigues LE 《Research in veterinary science》2007,83(1):27-29

Neospora caninum is a protozoon that causes abortion in cattle and neuromuscular lesions in dogs, with the formation of cysts mainly in the central nervous system. Since N. caninum is an intracellular parasite with tropism for the cells of nervous system, this study evaluated the respiratory metabolism of glial cells infected by this* parasite. Glial cultures obtained from the cerebral cortex of newborn rats were kept in DMEM enriched with 10% fetal bovine serum, 1 mM pyruvic acid and 2 mM of L-glutamine. They were infected at a ratio of approximately 1:1 (cell/parasite). Oxygen consumption was evaluated by polarography in the non infected and N. caninum infected groups, 24 and 72 h following infection. Glial cell respiration after 24 and 72 h was 307.2 +/- 34.7 and 308.9 +/- 64.1 microL of oxygen per mug of total protein per minute, and 566.2 +/- 54.6 and 579 +/- 117.5 microL O2/microg of total protein/minute in the control and infected groups, respectively. These results show that N. caninum does not interfere with glial respiration in vitro.  相似文献   

Use of culture-derived Fusarium oxysporum f. sp. cubense, race 1 filtrates for rapid and non-destructive in vitro differentiation between resistant and susceptible clones of field-grown banana     

Barbarita Companioni  Mayda Arzola  Yania Rodríguez  Marais Mosqueda  María Cristina Pérez  Orlando Borrás  José Carlos Lorenzo  Ramón Santos 《Euphytica》2003,130(3):341-347

Banana and plantain are among the most important food crops in developing countries but production is threatened by increasing virulent forms of Fusarium oxysporum f. sp. cubense. Chemical control is not economically effective and,therefore, breeding programs are necessary. Traditional field studies of new genotype resistance to this disease are time-consuming and destructive. Therefore,we developed a rapid and non-destructive procedure to differentiate field-grown banana resistant from susceptible clones. This procedure implicates application of culture filtrates of Fusarium oxysporum f. sp. cubense race 1 onto banana leaves. The relationship between duration of the fungal in vitro incubation, and the fungal culture fresh mass, the culture filtrate absorbency, and the Gross Michel (susceptible cultivar)leaf lesion area (after application of the culture filtrate) were similar and at 24day-incubation the highest values of the recorded indicators were observed. A comparison between Gross Michel and FHIA-01(resistant) was also performed. The most relevant differences between cultivars were observed at 48 hours after application of the culture filtrate, and in the middle-aged leaves. The position of the culture filtrate application in the leaf limb (distal, middle, proximal) was not determinant. A wider comparison among banana cultivars confirmed previous results informed by other researchers using different systems to study this plant-fungus interaction. Such a confirmation validates the effectiveness of the procedure described here to select rapid and non-destructively banana resistance to this disease at field level. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Resistance to common bacterial blight in Phaseolus vulgaris L. recombinant inbred lines under natural infection of Xanthomonas axonopodis pv. phaseoli     

C. Fortes Ferreira  M. Gonzaga Pereira  A. da Silva dos Santos  R. Rodrigues  R.E. Bressan-Smith  A. PioViana  R. Figueiredo Daher 《Euphytica》2003,134(1):43-46

Among the main causes of poor yield in common beans are fungal, viral and bacterial diseases. Common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli (Xap), is one of the major bacterial diseases leading to significant losses in Brazil. Chemical control is ineffective, therefore, the use of resistant varieties becomes an interesting alternative. The objective of the present work was to evaluate disease resistance under natural infection of the pathogen in 109 recombinant inbred lines (F₇) of P. vulgaris originated from the cross HAB-52 (susceptible — snapbean) × BAC-6 (resistant — common bean) in two different environments, as well as to calculate genetic parameters to assist in the selection of promising materials to be used in the CBB resistance breeding program. The data of the genetic parameters were compared to those calculated for the F₃ generation originated from the same cross. The heritability results for DI (disease index) and VI (variation index) in F₃ were 26.85% and 0.26, respectively, whereas in F₇ they were 91.77% and 1.36, respectively. These results demonstrate a potential to be explored for this advanced population, that in the future, along with other pathogen variability studies and tests in other environments, may provide more information regarding a more precise evaluation of promising genotypes to be used in common bean breeding programs aiming to obtain CBB resistant varieties. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Isozyme analysis of an active cassava germplasm bank collection     

Angélica V. V. Montarroyos  Marco A. G. de Lima  Elton O. dos Santos  José G. E. de França 《Euphytica》2003,130(1):101-106

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