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21.
Ontogeny of digestive enzymatic capacities in juvenile seahorses Hippocampus guttulatus fed on different live diets 
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下载免费PDF全文 Differences in survival and growth rates in seahorse Hippocampus guttulatus juveniles feeding on Artemia sp. or copepods have been related to specific digestive capacities of seahorse newborn, which are capable of actively forage on available prey from the first day of live. Other seahorse species, such as H. abdominalis and H. hippocampus, show high success feeding on Artemia nauplii suggesting species-specific differences in the digestibility of prey among seahorses. In this study, the profiles of digestive enzyme activity during the initial 15 days after release (DAR) were very low for trypsin, chitinase and α-amylase. In contrast, higher activities towards any of the assayed substrates for lipase (butyrate, octanoate and oleate) were evident from 0 DAR onwards. From 15 DAR onwards, the effect of diet composition became evident in juveniles previously fed on a mixed diet (Artemia + copepods), which showed a clear increase in all the assayed enzymes when compared with juveniles fed on Artemia as a sole prey. As a practical applicability of this study, a feeding schedule ensuring an adequate digestibility of the prey is proposed based on ontogenetic enzymatic activities of seahorse juveniles fed on different prey. 相似文献
22.
An evaluation of fish health‐management practices and occupational health hazards associated with Pangasius catfish (Pangasianodon hypophthalmus) aquaculture in the Mekong Delta,Vietnam 下载免费PDF全文
下载免费PDF全文 Tran Minh Phu Nguyen Thanh Phuong Tu Thanh Dung Dao Minh Hai Vo Nam Son Andreu Rico Jesper Hedegaard Clausen Henry Madsen Francis Murray Anders Dalsgaard 《Aquaculture Research》2016,47(9):2778-2794
This study aimed to evaluate the current status on the use of probiotics, disinfectants and antimicrobials in hatcheries, nurseries and grow‐out farms producing Pangasius catfish (Pangasianodon hypophthalmus) in the Mekong Delta, Vietnam. Semi‐structured interviews were conducted with 83 aquaculture enterprises (15 hatcheries, 32 nurseries and 36 grow‐out farms). Farmers reported use of a total of 24 different antimicrobials, e.g. for treatment of bacillary necrosis and motile aeromonad septicaemia, and a variety of disinfectants, probiotics and nutritional supplements. In contrast to small‐scale farmers, all large‐scale grow‐out farmers studied were certified and therefore had higher levels of formal education and specialized aquaculture training to diagnose and treat diseases. All farmers prepared their own medicated feed with a high risk of treatment failure, negative environmental impact from released antimicrobials and resistance development. Small‐scale farmers were at particular occupational health risks when handling antimicrobials and other chemicals, e.g. mixing medicated feed with bare hands. There is an urgent need to improve knowledge and use innovative approaches, e.g. private‐public partnerships, to assure a prudent use of chemicals, to improve capacity and access to disease diagnosis, particularly for small‐scale grow‐out farmers and nurseries. Efforts to control use of antimicrobials in aquaculture should be coordinated with the livestock and human health sectors taking an One‐Health approach. 相似文献
23.
María Candela Lobato Gustavo Raúl Daleo Adriana Balbina Andreu Florencia Pía Olivieri 《Potato Research》2018,61(1):19-29
The potato periderm is the outer tissue of potato tubers that protects the tuber from pathogen attack, dehydration, and wounding during harvest and storage. It is of secondary origin and replaces the epidermis early during tuber development. The outer layers of the periderm consist of cells with suberized walls. Phosphite compounds (Phi) are inorganic salts from phosphorous acid, and in previous works, we demonstrated that they are effective in protecting potato plants from biotic stress caused by different pathogens and also against UV-B radiation. The aim of the present work was to study the effect of Phi on the post-harvest potato periderm structure, cell wall components, and related enzymes. In three years of field experiments, potassium phosphite (KPhi) applications were compared with an untreated control. KPhi was applied to seed tubers before planting combined with foliage application of a conventional fungicide, to seed tubers and foliage without conventional fungicide, or to seed tubers combined with foliage application of KPhi plus a conventional fungicide. Observations of periderm sections showed increases in suberin and pectin depositions in post-harvest tubers from KPhi-treated plants compared to tubers from non-treated plants. In addition, peroxidase activity increased in the periderm tissue. The activity of laccases and superoxide dismutase was measured in the protein extract of the periderm, and an increase due to KPhi treatment was detected. The results presented here suggest that early KPhi treatment to seed tubers followed by foliage treatment leads to reinforcement of the cell wall of periderm cells, which represents a benefit for future response to stresses. 相似文献
24.
Immunocytochemistry of thyroid C-cell complexes in dogs 总被引：2，自引：0，他引：2
Ten thyroid C-cell complexes from five male and five female Beagle dogs, 1 to 2 years old, were studied using single and double immunocytochemical staining with the peroxidase-antiperoxidase technique. The antigens tested included thyroglobulin, calcitonin, calcitonin gene-related peptide, somatostatin, neuron specific enolase, and neurotensin. All C-cell complexes contained four cell types in various proportions: 1) follicular cells staining for thyroglobulin; 2) C-cells staining for calcitonin, calcitonin gene-related peptide, and neuron specific enolase; 3) stellate cells and cuboidal cells in follicle-like structures staining positively for somatostatin; and 4) undifferentiated cells staining negatively for all antigens. No positive immunoreactivity for neurotensin was detected. These findings support the hypothesis that thyroid C-cell complexes are ultimobranchial remnants that can give rise to thyroid follicles and C-cells. 相似文献
25.
Claudia Tonon Adriana Andreu Maria Elvira Aued Marcela Van Damme M. Huarte G. R. Daleo 《Potato Research》1998,41(4):319-325
Summary The kinetics of accumulation of chitinases, glucanases and phytoalexins were studied in two potato cultivars, differing in
their degrees of vertical and horizontal resistance, when infected with two races ofPhytophthora infestans. Tuber disks of cvs Kennebec (susceptible, low horizontal resistance) and Huinkul (tolerant, high horizontal resistance)
were infected with either race “0” (avirulent) or “C” (complex, race 1.3.5.7.11) ofPhytophthora infestans. Extracts of tuber tissue (0–7 days) from cv. Kennebec infected with race “0” showed a strong increase in phytoalexin production
and in chitinase and glucanase activities when compared with those infected with race “C”. These results indicate that race
“C” is able to block defensive reactions. No significant differences were observed in cv. Huinkul infected with both races.
The contribution of these reactions to horizontal resistance is unknown, and our results would not support a conclusive role
for them in the interaction. 相似文献
26.
F. P. Olivieri M. C. Lobato E. González Altamiranda G. R. Daleo M. Huarte M. G. Guevara A. B. Andreu 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(1):47-56
Since most plants possess resistance mechanisms which can be induced upon pre-treatment with a variety of chemical compounds,
the use of β-aminobutyric acid (BABA) as a defence inducer without reported toxic effect on the environment was studied. The
aim of this work was to analyse the effectiveness of BABA to induce resistance against Phytophthora infestans and Fusarium solani in potato cultivars differing in their level of resistance to late blight. The behaviour of some components of biochemical
mechanisms by which BABA increases resistance against P. infestans, as well as the effect of BABA on the activity of a potential pathogenic factor of F. solani, were studied. Plants with four applications of BABA throughout the crop cycle produced tubers more resistant to P. infestans and F. solani than non-treated plants. In addition, tuber slices from treated plants, inoculated with P. infestans, showed an increase in phenol and phytoalexin content. The aspartyl protease StAP1 accumulation was also higher in tubers obtained from treated plants and inoculated with P. infestans. This result was observed only in the more resistant potato cv. Pampeana, early after infection. In the potato–F. solani interaction, infected tubers coming from BABA-treated plants showed minor fungal proteolytic activity than infected, non-treated
ones. For potato cvs Pampeana and Bintje, the BABA treatment improved the yield of harvested tubers. The number of tubers
per plant and total weight of harvested tubers was greater for those obtained from treated plants with two early or four applications
of BABA. The results show that the BABA treatment increases the resistance of potatoes but the degree of increase depends
on the original level of resistance present in each cultivar. 相似文献
27.
Mouth Growth and Prey Selection in Juveniles of the European Long‐snouted Seahorse,Hippocampus guttulatus 下载免费PDF全文
下载免费PDF全文 Seahorses are ambush predators that swallow the prey through their tubular snout. In order to better understand mouth growth and its effect on prey preference by juveniles of the seahorse Hippocampus guttulatus, experimental assays were carried out by feeding juveniles (0–30 – d after male's pouch release [dar]) on a mixture of rotifers, Brachionus plicatilis; Artemia nauplii; and copepods; Acartia tonsa. Mouth development in juveniles was accomplished by growth of upper and lower jaws, which were linearly correlated with juvenile length, whereas mouth width (MW) and height (MH) grew exponentially with juvenile size. Additionally, MW and MH were exponentially correlated, so that the transversal section of the mouth increased linearly with juvenile age and length. Gut content and Ivlev' selectivity index demonstrated a permanent rejection of rotifers for the whole experimental period and a clear preference of juveniles for copepods from 0 to 15 dar and for Artemia nauplii afterwards. Results also suggest that juveniles are able to ingest larger prey than those provided as the limiting factor in prey ingestion was not MW, as for many marine fish larvae, but mouth area. A tentative feeding schedule to successfully feed H. guttulatus juveniles from 0 to 30 dar is proposed. 相似文献
28.
Steffensen SK Pedersen HA Labouriau R Mortensen AG Laursen B de Troiani RM Noellemeyer EJ Janovska D Stavelikova H Taberner A Christophersen C Fomsgaard IS 《Journal of agricultural and food chemistry》2011,59(22):12073-12082
Amaranthus hybridus and Amaranthus mantegazzianus are commonly cultivated and the entire young fresh plants consumed as vegetables in regions of Africa and Asia. A. hybridus and A. mantegazzianus were cultivated at four sites in three climate regions of the world: Santa Rosa, Argentina; Lleida, Spain; and Prague and Olomouc, both in the Czech Republic. The contents of flavonoids (isoquercitrin, rutin, nicotiflorin), hydroxybenzoic acids (protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid), hydroxycinnamic acids (caffeic acid, p-coumaric acid, ferulic acid), hydroxycinnamyl amides (N-trans-feruloyltyramine, N-trans-feruloyl-4-O-methyldopamine), and betaines (glycinebetaine, trigonelline) were determined. The variation in phytochemical content due to species and cultivation site was analyzed utilizing the multivariate statistical methods of principal component analysis (PCA) and graphical model (GM). The Argentinean samples differed from the three other locations due to higher contents of most compounds. The samples from Spain and the Czech Republic differed from each other in the content of the negatively correlated metabolites trigonelline and the flavonoids. The two amaranth species were separated primarily by a higher content of trigonelline and the two hydroxycinnamyl amides in A. mantegazzianus. The GM showed that the quantities of the different analytes within each compound group were intercorrelated except in the case of the betaines. The betaines carried no information on each other that was not given through correlations with other compounds. The hydroxycinnamic acids were a key group of compounds in this analysis as they separated the other groups from each other (i.e., carried information on all of the other groups). This study showed the contents of polyphenols and betaines in the aerial parts of vegetable amaranth to be very dependent on growth conditions, but also revealed that some of the compounds (trigonelline and the two hydroxycinnamyl amides) may be useful as features of a taxonomic classification. 相似文献
29.
María C. Lobato Milagros F. Machinandiarena Cecilia Tambascio Guillermo A. A. Dosio Daniel O. Caldiz Gustavo R. Daleo Adriana B. Andreu Florencia P. Olivieri 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(2):155-163
The utilization of phosphites (Phi) could be considered as another strategy to be included in integrated disease management
programmes to reduce the intensive use of fungicides and production costs. The aim of the present work was to analyze whether
the beneficial effects of phosphite treatment previously observed in potato plants grown under greenhouse conditions, were
reflected after harvest of field grown potatoes, both in disease protection and in yield. In addition, biochemical compounds
possibly involved in induced defence responses by Phi, like phytoalexins, pathogenesis related proteins and oxidative stress
enzymes were measured. Foliar applications of KPhi to field grown crops resulted in post-harvest tubers with a reduced susceptibility
to Phytophthora infestans, Fusarium solani and Erwinia carotovora infections, suggesting that this compound induced a systemic defence response. An increase in phytoalexin content in P. infestans inoculated tubers obtained from Phi-treated plants suggests their participation in the defence response. Chitinase content
increased 72 h after wounding or inoculation with P. infestans in tubers from KPhi-treated plants compared to wounded or infected tubers from non-treated plants. Contrary to this, the
isoforms of β-1,3-glucanases analyzed did not increase in the tubers of Phi-treated plants. The increment in peroxidase and
polyphenol oxidase activities indicated that these enzymes could be part of the Phi defence mechanism. No negative effects
were observed in potato yield at harvest, measured as total tuber weight and dry matter, after foliar KPhi treatment. This
suggests that the energetic cost involved in the defence response activation would not be detrimental to plant growth. 相似文献
30.