Redesigning metabolic routes: manipulation of TOL plasmid pathway for catabolism of alkylbenzoates   总被引：22，自引：0，他引：22  

J L Ramos  A Wasserfallen  K Rose  K N Timmis 《Science (New York, N.Y.)》1987,235(4788):593-596

Increasing quantities of man-made organic chemicals are released each year into the biosphere. Some of these compounds are both toxic and relatively resistant to physical, chemical, or biological degradation, and they thus constitute an environmental burden of considerable magnitude. Genetic manipulation of microbial catabolic pathways offers a powerful means by which to accelerate evolution of biodegradative routes through which such compounds might be eliminated from the environment. In the experiments described here, a catabolic pathway for alkylbenzoates specified by the TOL plasmid of Pseudomonas was restructured to produce a pathway capable of processing a new substrate, 4-ethylbenzoate. Analysis of critical steps in the TOL pathway that prevent metabolism of 4-ethylbenzoate revealed that this compound fails to induce synthesis of the catabolic enzymes and that one of its metabolic intermediates inactivates catechol 2,3-dioxygenase (C23O), the enzyme that cleaves the aromatic ring. Consequently, the pathway was sequentially modified by recruitment of genes from mutant bacteria selected for their production of either an altered pathway operon regulator that is activated by 4-ethylbenzoate or an altered C23O that is less sensitive to metabolite inactivation. The redesigned pathway was stably expressed and enabled host bacteria to degrade 4-ethylbenzoate in addition to the normal substrates of the TOL pathway.  相似文献   

Deep Impact observations by OSIRIS onboard the Rosetta spacecraft   总被引：1，自引：0，他引：1  

Keller HU  Jorda L  Küppers M  Gutierrez PJ  Hviid SF  Knollenberg J  Lara LM  Sierks H  Barbieri C  Lamy P  Rickman H  Rodrigo R 《Science (New York, N.Y.)》2005,310(5746):281-283

The OSIRIS cameras (optical, spectroscopic, and infrared remote imaging system) onboard the European Space Agency's Rosetta spacecraft observed comet 9P/Tempel 1 for 17 days continuously around the time of NASA's Deep Impact mission. The cyanide-to-water production ratio was slightly enhanced in the impact cloud, compared with that of normal comet activity. Dust particles were flowing outward in the coma at >160 meters per second, accelerated by the gas. The slope of the brightness increase showed a dip about 200 seconds after the impact. Dust Afrho values before and long after the impact confirm the slight decrease of cometary activity. The dust-to-water mass ratio was much larger than 1.  相似文献   

Changes in carotenoids and ABA content in Citrus leaves in response to girdling     

F. Rivas  F. Fornes  M.J. Rodrigo  L. Zacarías  M. Agustí 《Scientia Horticulturae》2011

The effect of girdling on abscisic acid, carotenoids content, xanthophylls cycle and non-photoquemical quenching was studied in leaves from different shoot types of containerized two-year-old ‘Loretina’ mandarin during spring flush period. Girdling increased abscisic acid in young leaves and decreased it in mature leaves. These changes were accompanied by a significant increase in leaf carotenoids, carotenoids:chlorophylls ratio, xanthophylls and xanthophylls cycle pool size and its de-epoxidation state in vegetative and multiflowered young leafy shoots. However, changes in de-epoxidation state did not correlate with the energy-dependent non-photochemical quenching. The role of carotenoids and abscisic acid as photoprotecting agents during the oxidative stress caused by girdling is discussed. In conclusion, this study provides evidence linking carotenoids-based photoprotecting mechanisms in the response to the stress induced by girdling in Citrus trees.  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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Detection, accumulation, distribution, and depletion of furaltadone and nifursol residues in poultry muscle, liver, and gizzard     

Barbosa J  Freitas A  Moura S  Mourão JL  Noronha da Silveira MI  Ramos F 《Journal of agricultural and food chemistry》2011,59(22):11927-11934

Nitrofurans were broadly used as an extremely effective veterinary antibiotic especially in pig and poultry production farms. Because of fears of the carcinogenic effects on humans, the nitrofurans were banned from use in livestock production in many countries, including the European Union. The present study examines the accumulation, distribution, and depletion of furaltadone and nifursol and of their tissue-bound metabolites [3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ) and 3,5-dinitro-salicylic acid hydrazine (DNSAH), respectively, in poultry edible tissues (muscle, liver, and gizzards) following administration to chickens of therapeutic and subtherapeutic concentrations of both compounds. Nitrofurans determination was performed by high-performance liquid chromatography-diode array detection and liquid chromatography-tandem mass spectrometry, respectively, for feeds and for poultry tissues. Furaltadone and nifursol, in very low concentrations, were found in samples of muscle, liver, and chicken's gizzard collected from slaughtered animals after 5 weeks of treatment and no withdrawal time period. When a withdrawal time period of 3 weeks was respected, no detectable nitrofuran parent compounds was observed in all of the studied matrices. For AMOZ, concentrations of 270 μg/kg in meat, 80 μg/kg in liver, and 331 μg/kg in gizzard were determined after administration of a medicated feed with furaltadone (132 mg/kg), 3 weeks after withdrawal of treatment. For DNSAH, the concentration values obtained are much lower than those observed for AMOZ. For meat, liver, and gizzard, DNSAH concentrations of 2.5, 6.4, and 10.3 μg/kg, respectively, were determined, after administration of a medicated feed with nifursol (98 mg/kg), 3 weeks after withdrawal of treatment. The gizzard could be considered a selected matrix for nitrofuran residues evaluation in poultry, due to its capacity of retaining either nitrofuran parent compounds or metabolites in higher concentrations, regardless of the administered dose or of the respected withdrawal time period.  相似文献   

Dorsal spinous process impingement syndrome ('kissing spine') in a cat: imaging appearance and surgical management     

Gutierrez-Quintana R  Lindley S  Sullivan M  Penderis J  Wessmann A 《Journal of Feline Medicine and Surgery》2011,13(8):618-621

Spinal pain is an important clinical presentation in feline patients, but the underlying causes can often be difficult to elucidate. Dorsal spinous process impingement syndrome ('kissing spine' or in human patients 'Baastrup syndrome') is a significant cause of spinal pain in equine and human patients and radiographically is characterised by a close approximation of adjacent spinous processes with reactive bone sclerosis affecting these spinous processes. In this report we describe the first reported case of dorsal spinous process impingement syndrome in a cat causing spinal pain, and successful surgical management of the syndrome. The affected cat presented at 5 years of age for evaluation of a 7-month history of progressive thoracolumbar pain. Radiographs revealed close approximation of the dorsal spinous processes of the seventh, eighth and ninth thoracic vertebrae (T7, T8 and T9), with associated reactive bone sclerosis. Surgical resection of the T8 dorsal spinous process resulted in complete resolution of the clinical signs with no evidence of recurrence 9 months after surgery.  相似文献   

A clinical comparison of remifentanil or alfentanil in propofol-anesthetized cats undergoing ovariohysterectomy     

Padilha ST  Steagall PV  Monteiro BP  Kahvegian MA  Ubukata R  Rodrigues EO  Rosa AL  Aguiar AJ 《Journal of Feline Medicine and Surgery》2011,13(10):738-743

Sixteen cats were used to compare the cardiovascular and anesthetic effects of remifentanil (REMI) or alfentanil (ALF) in propofol-anesthetized cats undergoing ovariohysterectomy. After premedication with acepromazine, anesthesia was induced and maintained with a constant rate infusion of propofol (0.3 mg/kg/min). REMI or ALF infusions were administered simultaneously with propofol. Heart rate (HR), systolic arterial pressure (SAP), pulse oximetry (SpO(2)), rectal temperature (RT), and response to surgical stimulation were recorded at predefined time points during anesthesia. Data [mean±standard deviation (SD)] were analyzed by analysis of variance (ANOVA) for repeated measures followed by a Dunnett's test and Student t-test (P<0.05). SAP was significantly lower in ALF group than in REMI group. Extubation time was significantly shorter in REMI than in ALF group. Overall infusion rate of REMI and ALF was 0.24±0.05 μg/kg/min and 0.97±0.22 μg/kg/min, respectively. The combination of propofol and REMI or ALF provided satisfactory anesthesia in cats undergoing ovariohysterectomy.  相似文献   

Comparison of a rebound and an applanation tonometer for measuring intraocular pressure in normal rabbits     

Pereira FQ  Bercht BS  Soares MG  da Mota MG  Pigatto JA 《Veterinary ophthalmology》2011,14(5):321-326

Objective To compare intraocular pressure (IOP) measurements made on healthy adult rabbits without the effect of tranquilizers using the new applanation tonometer, Tono‐Pen Avia^®, and the rebound tonometer Tonovet^®. Methods Intraocular pressure was measured throughout the day (6:00, 9:00, 12:00, 15:00, and 18:00 h) in 38 adult New Zealand White rabbits (76 eyes). The animals were 20 males and 18 females, with a mean weight of 3.5 kg and an average age of 6 months. A complete ocular exam (including Schirmer tear test, fluorescein staining, slit‐lamp biomicroscopy, and direct ophthalmoscopy) was performed on all animals at the beginning of the trial. Rebound tonometry was performed, and after 10 min, anesthetic drops were instilled and applanation tonometry was carried out. IOP values obtained using the two techniques were analyzed statistically. Results The mean IOP was 9.51 ± 2.62 mmHg with Tonovet^®, and 15.44 ± 2.16 mmHg with the Tono‐Pen Avia^®. Significant differences between measurements with the two tonometers were observed (P < 0.001). The linear regression equation describing the relationship between the two tonometers was y = 0.4923x + 10.754 (y = Tonovet^® and x = Tono‐Pen Avia^®). High IOPs were recorded in the early measurements (6:00), but the average IOPs from both devices were statistically similar throughout the day (P = 0.086). The correlation coefficient was r² = 0.357. No significant difference in IOP regarding gender was observed. Conclusion The Tono‐Pen Avia^® recorded higher levels of IOP compared with the Tonovet^®. Early in the day, the IOP of rabbits was higher than later in the day, regardless of the tonometer used.  相似文献   

Molecular and serological detection of Babesia spp. in neotropical and exotic carnivores in Brazilian zoos     

André MR  Adania CH  Teixeira RH  Allegretti SM  Machado RZ 《Journal of zoo and wildlife medicine》2011,42(1):139-143

Large and small piroplasms have been observed in the blood smears of various wild carnivores, but few studies utilizing molecular characterization have been done. The goal of this present study was to investigate the presence of Babesia sp. by molecular and serologic techniques in exotic and neotropical carnivores maintained in captivity at Brazilian zoos. Blood and sera samples were collected from 146 Brazilian wild felids, 21 exotic felids, 1 genet (Genetta tigrina), 3 European wolves (Canis lupus), and 94 Brazilian wild canids in Brazilian zoos in the S?o Paulo and Mato Grosso states and in the Federal District. A total of 53 wild felids (31.74%) and 10 wild canids (10.31%) were seropositive for Babesia canis by Indirect Fluorescent Antibody Test (IFAT). Antibodies were detected in ocelots, little-spotted cats, margays, pampas cats, jaguars, pumas, jaguarundis, crab-eating foxes, and bush dogs. Babesia sp. DNA, with high similarity to B. leo, was detected in one pampas cat and one genet.  相似文献   

Benefits and costs of street trees in Lisbon, Portugal     

A.L. Soares  F.C. Rego  E.G. McPherson  J.R. Simpson  P.J. Peper  Q. Xiao 《Urban Forestry & Urban Greening》2011,10(2):69

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