Characterization of aflatoxigenic and non-aflatoxigenic strains of <Emphasis Type="Italic">Aspergillus</Emphasis> section <Emphasis Type="Italic">Flavi</Emphasis> isolated from corn grains of different geographic origins in Brazil     

Liliana de Oliveira Rocha  Gabriela Martins Reis  Raquel Braghini  Estela Kobashigawa  Jansen de Araújo  Benedito Corrêa 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(3):353-366

Aflatoxins can cause great economic losses and serious risks to humans and animals health. The largest aflatoxin producers belong to Aspergillus section Flavi and can occur naturally in food commodities. Studies showed that molecular tools as well as the type of sclerotia produced by the strains could be helpful for identification of Aspergillus species and could be correlated with levels of toxin production. The purpose of this work was to characterize the genetic diversity using AFLP technique, the type of sclerotia and the ability of aflatoxin production by isolated strains from corn of different origins in Brazil, and to verify whether qPCR based on aflR and aflP genes is appropriate for estimating the level of aflatoxin production. All the 75 strains were classified as A. flavus and the AFLP technique showed a wide intraspecific variability within them. Regarding sclerotia production, 34% were classified as S and 66% as L type. Among the aflatoxin-producers, 52.8% produced aflatoxin B₁, while 47.2% aflatoxins B₁ and B₂. Statistical analysis showed no correlation between sclerotia production and aflatoxigenicty, and no correlation between the phylogenetic clusters and aflatoxin production. Concerning the relative expression of aflR and aflP, Pearson’s correlation test demonstrated low positive correlation between the expression of the aflR and aflP genes and the production of AFB₁ and AFB₂, but showed high positive correlation between aflR and aflP expression. In contrast to the other reference strains, A. oryzae ATCC 7282 showed no amplification of aflR and aflP. The results highlight the need for detection of reliable and reproducible markers with a high positive correlation with aflatoxin production.  相似文献   

Development of Dermanyssus gallinae (Acari: Dermanyssidae) at different temperatures     

Tucci EC  Prado AP  Araújo RP 《Veterinary parasitology》2008,155(1-2):127-132

The development, viability, and life cycle parameters of Dermanyssus gallinae at five different temperatures (15, 20, 25, 30 and 35 degrees C), and at relative humidity 70-85% were evaluated. Life cycle duration was 690.75 h (28 days) at 15 degrees C, 263.12h (11 days) at 20 degrees C, 164.63 h (7 days) at 25 degrees C, 140.69 h (6 days) at 30 degrees C and 172.04 h (7 days) at 35 degrees C. The optimal development temperature for D. gallinae was 30 degrees C, with the greatest survival in all stages and the shortest development time. High mortality at 35 degrees C indicated that this temperature had adverse effects on development of D. gallinae, and that in field conditions D. gallinae populations may decrease or even disappear due to the negative impact of high temperature on development. There were no significant differences in the pre-oviposition period among the four temperatures 20-35 degrees C, indicating that temperature did not affect this part of the life cycle.  相似文献   

Anthelmintic efficacy of neem (Azadirachta indica A. Juss) and the homeopathic product Fator Vermes in Morada Nova sheep     

Chagas AC  Vieira LS  Freitas AR  Araújo MR  Araújo-Filho JA  Araguão WR  Navarro AM 《Veterinary parasitology》2008,151(1):68-73

Gastrointestinal nematodes are becoming increasingly resistant to the commercial products used to control them. The cost of routine vermifuge applications on herds and the problem of residues in animal products and the environment have prompted research on the anthelmintic activity of plant extracts. This work examines the anthelmintic action of neem and the homeopathic product Fator Vermes in sheep kept in a pasture for 18 months. Forty sheep of the Morada Nova breed were divided into four treatments and the control, according to the EPG. During the experiment, each animal received 100 g/day of shredded corn and did not receive protein supplementation. In treatment 1 (control), the animals received only shredded corn. Treatment 2 received 1.6 g/(animal day) of the homeopathic product mixed with the shredded corn, and treatments 3, 4 and 5 received, respectively, 12.5, 25.0 and 37.5 g/(animal day) of dried Azadirachta indica leaves mixed with the shredded corn. The neem was administered for alternating 15-day periods and the homeopathic product daily for 18 months. There were 39 fortnightly fecal collections made to count the EPG, and fecal cultures were performed monthly. The following genera, in percentage, were identified: Haemonchus: 65.58+/-3.27, Trichostrongylus: 15.92+/-7.38 and Oesophagostomum: 18.50+/-6.22. The treatments evaluated were not effective in controlling gastrointestinal nematodes (P>0.05), whose mean log(10) counts (EPG +1) and standard errors for treatments 1-5 were respectively 3.55+/-0.28; 3.48+/-0.31; 3.90+/-0.29; 2.78+/-0.29 and 3.48+/-0.30. A significant effect (P<0.0001) was observed of the periods of the year when the 39 collections occurred. Because of the diet deficient in raw protein, the sheep had higher average EPG counts, for all the treatments, at the end of the dry season, and the opposite occurred in the middle of the rainy season.  相似文献   

Artificial structures as tools for fish habitat rehabilitation in a neotropical reservoir     

Luciano N. Santos  Francisco G. Araújo  Daniel S. Brotto 《水产资源保护:海洋与淡水生态系统》2008,18(6):896-908

• 1. Since most of the natural habitats critical for freshwater fish survival have been adversely affected by human disturbance, the effectiveness of artificial structures in providing new and suitable habitats for fish has been increasingly investigated.
• 2. This paper evaluates the role of artificial structures as fish habitat in a structureless 30 km² Brazilian reservoir, through underwater surveys conducted monthly from April 1999 to March 2000.
• 3. In total, 5759 fish in nine species were recorded, but only three cichlid species—one native, Geophagus brasiliensis and two non‐native, Cichla kelberi and Tilapia rendalli—showed consistent association with the artificial habitats, suggesting that this family reacts to submerged structures.
• 4. The absence of fish at control sites compared with high occurrences in sites provided with a physically complex structure suggests that artificial structures can play an important ecological role for cichlids smaller than 150 mm TL, probably related to shelter and/or feeding benefits.
• 5. The level of structural complexity and position in the water column influenced fish use of artificial structures. C. kelberi was associated with highly complex structures, whereas moderately complex bottom structures were more effective in harbouring G. brasiliensis. Bottom structures are apparently more important than midwater structures in harbouring T. rendalli, but structural complexity seemed to play a secondary role.
• 6. This study is the first in demonstrating that adding complex artificial structures can expand habitats for small fish (<150 mm TL), especially cichlids, in a neotropical impoundment. It seems reasonable to expect that deploying physically complex structures in other oligotrophic, structureless and cichlid‐dominated impoundments in Brazil will lead to similar results to those found in this work.

Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Ecosystem effects of invertebrate fisheries          下载免费PDF全文

Tyler D Eddy  Heike K Lotze  Elizabeth A Fulton  Marta Coll  Cameron H Ainsworth  Júlio Neves de Araújo  Catherine M Bulman  Alida Bundy  Villy Christensen  John C Field  Neil A Gribble  Mejs Hasan  Steve Mackinson  Howard Townsend 《Fish and Fisheries》2017,18(1):40-53

Since the 1950s, invertebrate fisheries catches have rapidly expanded globally to more than 10 million tonnes annually, with twice as many target species, and are now significant contributors to global seafood provision, export, trade and local livelihoods. Invertebrates play important and diverse functional roles in marine ecosystems, yet the ecosystem effects of their exploitation are poorly understood. Using 12 ecosystem models distributed worldwide, we analysed the trade‐offs of various invertebrate fisheries and their ecosystem effects as well as ecological indicators. Although less recognized for their contributions to marine food webs, our results show that the magnitude of trophic impacts of invertebrates on other species of commercial and conservation interest is comparable with those of forage fish. Generally, cephalopods showed the strongest ecosystem effects and were characterized by a strong top‐down predatory role. Lobster, and to a lesser extent, crabs, shrimp and prawns, also showed strong ecosystem effects, but at lower trophic levels. Benthic invertebrates, including epifauna and infauna, also showed considerable ecosystem effects, but with strong bottom‐up characteristics. In contrast, urchins, bivalves, and gastropods showed generally lower ecosystem effects in our simulations. Invertebrates also strongly contributed to benthic–pelagic coupling, with exploitation of benthic invertebrates impacting pelagic fishes and vice versa. Finally, on average, invertebrates produced maximum sustainable yield at lower levels of depletion (~45%) than forage fish (~65%), highlighting the need for management targets that avoid negative consequences for target species and marine ecosystems as a whole.  相似文献   

Phytoextraction of Lead from Soil from a Battery Recycling Site: The Use of Citric Acid and NTA     

Josângela do Carmo Trezena de Araújo  Clístenes Williams Araújo do Nascimento 《Water, air, and soil pollution》2010,211(1-4):113-120

Phytoextraction is a soil remediation technique involving plants that concentrate heavy metals in their shoots, which may be removed from the area by harvest. The application of synthetic chelants to soil increases metal solubility, and therefore enhances phytoextraction. However, synthetic chelants degrade poorly in soil, and metal leaching poses a threat to human and animal health. The aim of this study is to assess the use of two biodegradable chelants (citric acid and nitrilotriacetic acid (NTA)) for Pb phytoextraction by maize from a soil contaminated by battery-casing disposal. In order to assess the behavior of a non-degradable chelant, ethylenediaminetetraacetic acid (EDTA) was also included in the experiment. The chelants NTA and EDTA were applied to soil pots at rates of 0, 3, 5, 7, and 10 mmol kg^?1 of soil. The rates used to citric acid were 0, 5, 10, 15, and 30 mmol kg^?1. Maize plants were grown for 72 days and chelants were applied 9 days before harvest. Soil samples were extracted with CaCl₂ to assess the Pb solubility after chelants application. The results showed that NTA was more efficient than citric acid to solubilize Pb from soil; however, citric acid promoted higher net removal of Pb (120 mg pot^?1) than NTA (57 mg pot^?1). Thus, the use of citric acid, a biodegradable organic acid, could be feasible for enhancing the phytoextraction of Pb from the site studied with no environmental constraints.  相似文献   

Improving the prediction performance of a large tropical vis‐NIR spectroscopic soil library from Brazil by clustering into smaller subsets or use of data mining calibration techniques     

S. R. Araújo  J. Wetterlind  J. A. M. Demattê  B. Stenberg 《European Journal of Soil Science》2014,65(5):718-729

Effective agricultural planning requires basic soil information. In recent decades visible near‐infrared diffuse reflectance spectroscopy (vis‐NIR) has been shown to be a viable alternative for rapidly analysing soil properties. We studied 7172 samples of seven different soil types collected from several regions of Brazil and varying in organic matter (OM) (0.2–10.3%) and clay content (0.2–99.0%). The aim was to explore the possibility of enhancing the performance of vis‐NIR data in predicting organic matter and clay content in this library by dividing it into smaller sub‐libraries on the basis of their vis‐NIR spectra. We used partial least square regression (PLSR) models on the sub‐libraries and compared the results with PLSR and two non‐linear calibration techniques, boosted regression trees (BT) and support vector machines (SVM) applied to the whole library. The whole library calibrations for clay performed well (ME (modelling efficiency) > 0.82; RMSE (root mean squared error) < 10.9%), reflecting the influence of the direct spectral responses of this property in the vis‐NIR range. Calibrations for OM were reasonably good, especially in view of the very small variation in this property (ME > 0.60; RMSE < 0.55%). The best results were, however, found when dividing the large library into smaller subsets by using variation in the mean‐normalized or first derivative spectra. This divided the global data set into clusters that were more uniform in mineralogy, regardless of geographical origin, and improved predictive performance. The best clustering method improved the RMSE in the validation to 8.6% clay and 0.47% OM, which corresponds to a 21% and 15% reduction, respectively, as compared with whole library PLSR. For the whole library, SVM performed almost equally well, reducing RMSE to 8.9% clay and 0.48% OM.  相似文献   

Impact of Probing the Reproductive Tract During Early Pregnancy on Fertility of Beef Cows     

G Pugliesi  SC Scolari  FS Mesquita  M Maturana Filho  ER Araújo  D Cardoso  JN Sales  I Martin  M Sá Filho  CM Bertan  M Binelli 《Reproduction in domestic animals》2014,49(4):e35-e39

This short communication reports the impact of endometrial biopsies, uterine flushings and follicular fluid aspiration procedures at day 6 post artificial insemination (AI) on pregnancy rates. In Experiment 1, cows were timed AI (TAI) and assigned to the following treatment groups: control (n = 37), uterine flushing (n = 35) and endometrial biopsy (n = 38). On day 30 post AI, pregnancy rates were 40.5%, 33% and 28.5%, respectively (p > 0.1). Pregnancy rate on day 60 was lower (p < 0.004) in flushed cows than in the controls. In Experiment 2, oestrus was detected and cows were assigned to flushing (n = 32) or biopsy (n = 33) treatments 6 days after AI, which resulted in pregnancy rates of 31% and 36%, respectively (p > 0.1). In Experiment 3, cows were, 6 days after TAI, randomly assigned to the following treatments: control (n = 84) or aspiration of the largest follicle (n = 73). Pregnancy rates on day 30 post AI were 63.5% for the control group and 53% for the aspirated group (p > 0.1). In conclusion, uterine flushing and endometrial biopsy negatively affect pregnancy rates, but neither procedure can be considered to be incompatible with pregnancy maintenance. Follicular aspiration during pregnancy does not interact with pregnancy success. The amount and quality of samples obtained are compatible with the use of cellular and molecular analysis of uterine variables from cows that failed or succeeded on maintaining pregnancy.  相似文献   

Amazonian deforestation models     

Câmara G  Dutra Aguiar AP  Escada MI  Amaral S  Carneiro T  Vieira Monteiro AM  Araújo R  Vieira I  Becker B 《Science (New York, N.Y.)》2005,307(5712):1043-4; author reply 1043-4

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Elemental Distribution in a Sedimentary Deposit on the Shelf Off the Tagus Estuary (Portugal)     

P. Paiva  J.-M. Jouanneau  F. Araújo  O. Weber  A. Rodrigues  J.M.A. Dias 《Water, air, and soil pollution》1997,99(1-4):507-514

The Tagus estuary, located at the western Iberian coast in front of Lisbon is the largest one in Portugal, where it drains highly populated and industrialised regions. The amount of sediment transported by this river is so great that the submarine delta is one of the largest in the Iberian margin, very well defined and reaching the 70m isobath. The geochemical pattern of the muddy deposit off the Tagus river has been determined by elemental analyses of bulk surficial sediments, collected at the Portuguese margin adjacent to the Tagus estuary. Measurements were carried out by energy-dispersive X-ray fluorescence spectrometry (EDXRF). Sediments were usually composed of fine particles (silts and clays) and were high in organic matter (measured as loss on ignition). Elemental concentrations for Zn and Ph clearly indicate an estuarine contamination probably associated with discharges from urban centers or due to the influence of the industries located downstream. apparently the depletion on the Cu contents is caused by its release (soluble complexes) into the marine environment. Variations observed in the elemental distribution of the sediments of the Tagus with distance from the estuary seem to be dependent on the grain size distribution related to the dynamics of the sediment transport.  相似文献