Transformation of the nitrogen cycle: recent trends, questions, and potential solutions   总被引：12，自引：0，他引：12  

Galloway JN  Townsend AR  Erisman JW  Bekunda M  Cai Z  Freney JR  Martinelli LA  Seitzinger SP  Sutton MA 《Science (New York, N.Y.)》2008,320(5878):889-892

Humans continue to transform the global nitrogen cycle at a record pace, reflecting an increased combustion of fossil fuels, growing demand for nitrogen in agriculture and industry, and pervasive inefficiencies in its use. Much anthropogenic nitrogen is lost to air, water, and land to cause a cascade of environmental and human health problems. Simultaneously, food production in some parts of the world is nitrogen-deficient, highlighting inequities in the distribution of nitrogen-containing fertilizers. Optimizing the need for a key human resource while minimizing its negative consequences requires an integrated interdisciplinary approach and the development of strategies to decrease nitrogen-containing waste.  相似文献   

Development of transgenic fungi that kill human malaria parasites in mosquitoes     

Fang W  Vega-Rodríguez J  Ghosh AK  Jacobs-Lorena M  Kang A  St Leger RJ 《Science (New York, N.Y.)》2011,331(6020):1074-1077

Metarhizium anisopliae infects mosquitoes through the cuticle and proliferates in the hemolymph. To allow M. anisopliae to combat malaria in mosquitoes with advanced malaria infections, we produced recombinant strains expressing molecules that target sporozoites as they travel through the hemolymph to the salivary glands. Eleven days after a Plasmodium-infected blood meal, mosquitoes were treated with M. anisopliae expressing salivary gland and midgut peptide 1 (SM1), which blocks attachment of sporozoites to salivary glands; a single-chain antibody that agglutinates sporozoites; or scorpine, which is an antimicrobial toxin. These reduced sporozoite counts by 71%, 85%, and 90%, respectively. M. anisopliae expressing scorpine and an [SM1](8):scorpine fusion protein reduced sporozoite counts by 98%, suggesting that Metarhizium-mediated inhibition of Plasmodium development could be a powerful weapon for combating malaria.  相似文献   

Evaluation of genotypic variation of broccoli (Brassica oleracea var. italic) in response to selenium treatment     

Ramos SJ  Yuan Y  Faquin V  Guilherme LR  Li L 《Journal of agricultural and food chemistry》2011,59(8):3657-3665

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Voltammetric determination of the antioxidant capacity in wine samples using a carbon nanotube modified electrode     

Souza LP  Calegari F  Zarbin AJ  Marcolino-Junior LH  Bergamini MF 《Journal of agricultural and food chemistry》2011,59(14):7620-7625

A direct determination of gallic acid was achieved at a carbon paste electrode modified with carbon nanotubes under differential pulse voltammetry conditions. The values obtained for gallic acid were used to estimate the antioxidant properties of the wine sample based on gallic acid oxidation. The proposed method is based on the gallic acid oxidation process at a modified carbon paste electrode (MCPE) containing 30% (m/m) of carbon nanotubes monitored at 0.35 V versus Ag/AgCl (KCl 3 mol L(-1)). Using the optimized experimental conditions, the calibration curve for gallic acid was linear in the concentration range from 5.0 × 10(-7) to 1.5 × 10(-5) mol L(-1) with a detection limit of 3.0 × 10(-7) mol L(-1). The MCPE was successfully applied for the determination of the antioxidant capacity for red and white wine samples without interference of glucose and ascorbic acid, and the obtained results were compared with the standard spectrophotometric method.  相似文献   

Cone beam computed tomography and intraoral radiography for diagnosis of dental abnormalities in dogs and cats     

Marcello R. Roza  Luiz Antonio F. Silva  Mauricio Barriviera  Alessandro L. Janu��rio  Ana Cristina B. Bezerra  Maria Clorinda S. Fioravanti 《Journal of veterinary science (Suw?n-si, Korea)》2011,12(4):387-392

The development of veterinary dentistry has substantially improved the ability to diagnose canine and feline dental abnormalities. Consequently, examinations previously performed only on humans are now available for small animals, thus improving the diagnostic quality. This has increased the need for technical qualification of veterinary professionals and increased technological investments. This study evaluated the use of cone beam computed tomography and intraoral radiography as complementary exams for diagnosing dental abnormalities in dogs and cats. Cone beam computed tomography was provided faster image acquisition with high image quality, was associated with low ionizing radiation levels, enabled image editing, and reduced the exam duration. Our results showed that radiography was an effective method for dental radiographic examination with low cost and fast execution times, and can be performed during surgical procedures.  相似文献   

Transmission electron microscopy for characterization of acrosomal damage after Percoll gradient centrifugation of cryopreserved bovine spermatozoa     

Letícia Z. Oliveira  Vera F. M. Hossepian de Lima  Marcelo A. Levenhagen  Ricarda M. dos Santos  Terezinha I. Assump??o  José O. Jacomini  André F. C. de Andrade  Rubens P. de Arruda  Marcelo E. Beletti 《Journal of veterinary science (Suw?n-si, Korea)》2011,12(3):267-272

The objective of this study was to characterize acrosomal ultrastructure following discontinuous Percoll gradient centrifugation of cryopreserved bovine sperm. Semen was collected from six bulls of different breeds and three ejaculates per bull were evaluated. Frozen semen samples were thawed and the acrosomal region of sperm cells was evaluated by transmission electron microscopy (TEM) before (n = 18) and after (n = 18) Percoll centrifugation. The evaluation of 20 sperm heads from each of the 36 samples analyzed ensured that a large number of cells were investigated. The data were subjected to analysis of variance at a level of significance of 5%. Percoll centrifugation reduced the percentage of sperm exhibiting normal acrosomes (from 61.77 to 30.24%), reduced the percentage of sperm presenting atypical acrosome reactions (from 28.38 to 4.84%) and increased the percentage of sperm exhibiting damage in the acrosome (from 6.14 to 64.26%). The percentage of sperm with typical acrosome reactions was not significantly different before (3.70%) and after (0.67%) centrifugation. TEM distinguished four different types of acrosomal status and enabled ultrastructural characterization of acrosomal injuries. The percentage of sperm exhibiting normal acrosomes decreased and damage in the acrosome was the most frequent acrosomal injury with the Percoll gradient centrifugation protocol utilized.  相似文献   

Tracheostomy tube occlusion during emergency tracheostomy in a pigmy goat     

Santos LC  Gleed RD  Campoy L  Martin-Flores M  Ludders JW 《Veterinary anaesthesia and analgesia》2011,38(6):624-625

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Management, breeding, and health records from a captive colony of pekin robins (Leiothrix lutea), 2001 - 2010     

da Cruz CE  de Oliveira LG  Boabaid FM  Zimermann FC  Stein G  Marks F  Cerva C  Lieberknecht C  Canal CW  Driemeier D 《Journal of zoo and wildlife medicine》2011,42(3):451-459

Pekin robins (Leiothrix lutea) were once the most widely kept softbills in captivity. As a result of the Convention on the International Trade of Endangered Species of Fauna and Flora (CITES-1997), the worldwide trade of wild-caught pekin robins has been prohibited due to the depletion of native populations of this species. In Brazil, as in other countries, pekin robins imported prior to the enactment of the CITES have disappeared from aviaries because the end of the birds' natural life span has passed, and only very few captive-bred pekin robins now exist. While captive propagation fails to address the primary causes of wild bird population decline, it might help the recovery of populations of this species. This article presents records made over a 10-yr period of a captive colony of pekin robins. Emphasis is placed on the management of the flock, the ailments affecting the birds, and the findings associated with bird losses. The main causes of bird losses included rearing management failures and age-related disorders.  相似文献   

Convergence of developmental mutants into a single tomato model system: 'Micro-Tom' as an effective toolkit for plant development research     

Carvalho RF  Campos ML  Pino LE  Crestana SL  Zsögön A  Lima JE  Benedito VA  Peres LE 《Plant methods》2011,7(1):18-14

Background

The tomato (Solanum lycopersicum L.) plant is both an economically important food crop and an ideal dicot model to investigate various physiological phenomena not possible in Arabidopsis thaliana. Due to the great diversity of tomato cultivars used by the research community, it is often difficult to reliably compare phenotypes. The lack of tomato developmental mutants in a single genetic background prevents the stacking of mutations to facilitate analysis of double and multiple mutants, often required for elucidating developmental pathways.

Results

We took advantage of the small size and rapid life cycle of the tomato cultivar Micro-Tom (MT) to create near-isogenic lines (NILs) by introgressing a suite of hormonal and photomorphogenetic mutations (altered sensitivity or endogenous levels of auxin, ethylene, abscisic acid, gibberellin, brassinosteroid, and light response) into this genetic background. To demonstrate the usefulness of this collection, we compared developmental traits between the produced NILs. All expected mutant phenotypes were expressed in the NILs. We also created NILs harboring the wild type alleles for dwarf, self-pruning and uniform fruit, which are mutations characteristic of MT. This amplified both the applications of the mutant collection presented here and of MT as a genetic model system.

Conclusions

The community resource presented here is a useful toolkit for plant research, particularly for future studies in plant development, which will require the simultaneous observation of the effect of various hormones, signaling pathways and crosstalk.  相似文献   

Interactive responses of gala apple fruit volatile production to controlled atmosphere storage and chemical inhibition of ethylene action   总被引：2，自引：0，他引：2  

Mattheis JP  Fan X  Argenta LC 《Journal of agricultural and food chemistry》2005,53(11):4510-4516

Gala apples exposed to the ethylene action inhibitor 1-methylcyclopropene (1-MCP) for 12 h at 20 degrees C were stored at 1 degrees C in air or a controlled atmosphere (CA) maintained at 1 kPa O2 and 2 kPa CO2. Volatile compounds were measured after 4, 12, 20, and 28 weeks plus 1 or 7 days at 20 degrees C. Treatment with 1-MCP and then storage in air or CA or storage in CA without 1-MCP treatment reduced volatile production as compared to apples not treated with 1-MCP stored in air. The reduced production of esters, alcohols, aldehydes, acetic acid, and 1-methoxy-4-(2-propenyl)benzene was observed. Ester production by fruit stored in CA decreased throughout the storage period regardless of previous 1-MCP treatment. The production of esters, alcohols, aldehydes, acetic acid, and 1-methoxy-4-(2-propenyl)benzene by 1-MCP-treated fruit stored in air plus 7 days at 20 degrees C increased after 20 or 28 weeks of storage. Continuous exposure to 417 micromol m(-3) ethylene for 7 days at 20 degrees C after 12 or 28 weeks of storage stimulated production of many volatile compounds, primarily esters and alcohols, by fruit stored in CA or 1-MCP-treated apples stored in air. However, exposure to ethylene had no effect on the production of aldehydes or acetic acid.  相似文献