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951.
Unhealthy diets, lack of fitness, and obesity are serious problems in the United States. The Centers for Disease Control, Surgeon General, and Department of Health and Human Services are calling for action to address these problems. Scientists and educators at Baylor College of Medicine and the National Space Biomedical Research Institute teamed to produce an instructional unit, "Food and Fitness," and evaluated it with students in grades 3-7 in Houston, Texas. A field-test group (447 students) completed all unit activities under the guidance of their teachers. This group and a comparison group (343 students) completed pre and postassessments measuring knowledge of concepts covered in the unit. Outcomes indicate that the unit significantly increased students' knowledge and awareness of science concepts related to energy in living systems, metabolism, nutrients, and diet. Pre-assessment results suggest that most students understand concepts related to calories in food, exercise and energy use, and matching food intake to energy use. Students' prior knowledge was found to be much lower on topics related to healthy portion sizes, foods that supply the most energy, essential nutrients, what "diet" actually means, and the relationship between body size and basal metabolic rate. 相似文献
952.
González Moreno PA Robles Medina A Camacho Rubio F Camacho Páez B Molina Grima E 《Biotechnology progress》2004,20(4):1044-1052
Structured triacylglycerols (ST) enriched in eicosapentaenoic acid (EPA) in position 2 of the triacylglycerol (TAG) backbone were synthesized by acidolysis of a commercially available EPA-rich oil (EPAX4510, 40% EPA) and caprylic acid (CA), catalyzed by the 1,3-specific immobilized lipase Lipozyme IM. The reaction was carried out in a packed bed reactor (PBR) operating in two ways: (1) by recirculating the reaction mixture from the exit of the bed to the substrate reservoir (discontinuous mode) and (2) in continuous mode, directing the product mixture leaving the PBR to a product reservoir. By operating in these two ways and using a simple kinetic model, representative values for the apparent kinetic constants (kX) for each fatty acid (native, Li or odd, M) were obtained. The kinetic model assumes that the rate of incorporation of a fatty acid into TAG per amount of enzyme, rX (mole/(h g lipase)) is proportional to the extent of the deviation from the equilibrium for each fatty acid (i.e., the difference of concentration between the fatty acid in the triacylglycerol and the concentration of the same fatty acid in the triacylglycerol once the equilibrium of the acidolysis reaction is reached). The model allows comparing the two operating modes through the processing intensity, defined as mLt/(V[TG]0) and mL/(q[TG]0), for the discontinuous and continuous operation modes, respectively. In discontinuous mode, ST with 59.5% CA and 9.6% EPA were obtained. In contrast, a ST with 51% CA and 19.6% EPA were obtained when using the continuous operation mode. To enhance the CA incorporation when operating in continuous mode, a two-step acidolysis reaction was performed (third operation mode). This continuous two-step process yields a ST with a 64% CA and a 15% EPA. Finally, after purifying the above ST in a preparative silica gel column, impregnated with boric acid, a ST with 66.9% CA and 19.6% EPA was obtained. The analysis by reverse phase and Ag+ liquid chromatography of the EPA-enriched ST demonstrated that the CA was placed in positions 1 and 3 and the EPA was occupying position 2 of the final ST. 相似文献
953.
Greenhouse experiments were conducted in two years (1993–1994) with eggplants supplied with 1, 2 or 4 mM NH4NO3 as the N source in order to determine its influence on molybdenum (Mo) and nitrate (NO3
–) content in leaf blades, petioles, and fruits as well as leaf nitrate reductase (NR) activity. The results reveal that 2 and 4 mM NH4NO3 altered shoot Mo distribution and thus affecting the NR activity. 相似文献
954.
Estrada-Reyes R Alvarez AL López-Rubalcava C Rocha L Heinze G Moreno J Martínez-Vázquez M 《Zeitschrift für Naturforschung. C, Journal of biosciences》2002,57(1-2):29-32
A new furofuranic lignan named (+)-epimembrine together with known (+)-epieudesmine and (+)-epimagnoline were isolated from leaves of R. mucosa. Their structures were determined by spectroscopic data. Palmitone and a mixture of beta-sitosterol and stigmasterol were also isolated. 相似文献
955.
Gil F López-Albors O Vázquez JM Latorre R Ramírez-Zarzosa G Moreno F 《Histology and histopathology》2001,16(2):439-442
Using a variety of histochemical methods -mATPase staining after alkaline and acid preincubations, NADH-TR and alpha-MGPDH- we have investigated the fibre types in porcine skeletal muscle. The results reveal that four major fibre types -I, IIA, IIB and II*- can be separated histochemically in Longissimus lumborum muscle of Landrace pigs. The histochemical properties of the muscle fibre type II* are very similar to that of type IIX described in other mammals. The existence of IIX fibres in pig muscle has been recently demonstrated by molecular biology techniques and our results validate the use of histochemistry (mATPase) as an easy methodology to differentiate the three fast myosins (type II fibres) in pig muscle. 相似文献
956.
A plasma membrane-type Ca(2+)-ATPase co-localizes with a vacuolar H(+)-pyrophosphatase to acidocalcisomes of Toxoplasma gondii 总被引:7,自引:0,他引:7
Ca(2+)-ATPases are likely to play critical roles in the biochemistry of Toxoplasma gondii, since these protozoa are obligate intracellular parasites and the Ca(2+) concentration in their intracellular location is three orders of magnitude lower than in the extracellular medium. Here, we report the cloning and sequencing of a gene encoding a plasma membrane-type Ca(2+)-ATPase (PMCA) of T.gondii (TgA1). The predicted protein (TgA1) exhibits 32-36% identity to vacuolar Ca(2+)-ATPases of Trypanosoma cruzi, Saccharomyces cerevisiae, Entamoeba histolytica and Dictyostelium discoideum. Sequencing of both cDNA and genomic DNA from T.gondii indicated that TgA1 contains two introns near the C-terminus. A hydropathy profile of the protein suggests 10 transmembrane domains. TgA1 suppresses the Ca(2+) hypersensitivity of a mutant of S.cerevisiae that has a defect in vacuolar Ca(2+) accumulation. Indirect immunofluorescence and immunoelectron microscopy analysis indicate that TgA1 localizes to the plasma membrane and co-localizes with the vacuolar H(+)-pyrophosphatase to intracellular vacuoles identified morphologically and by X-ray microanalysis as the acidocalcisomes. This vacuolar-type Ca(2+)-ATPase could play an important role in Ca(2+) homeostasis in T.gondii. 相似文献
957.
Angelini S Moreno R Gouffi K Santini C Yamagishi A Berenguer J Wu L 《FEBS letters》2001,506(2):103-107
The bacterial twin-arginine translocation (Tat) pathway is distinct from the Sec system by its remarkable capacity to export folded enzymes. To address the question whether the two systems are capable of translocating homologous enzymes catalyzing the same reaction, we cloned the tap gene encoding Thermus thermophilus alkaline phosphatase (Tap) and expressed it in Escherichia coli. Unlike the alkaline phosphatase of E. coli, which is translocated through the Sec system and then activated in the periplasm, Tap was exported exclusively via the Tat pathway and active Tap precursor was observed in the cytoplasm. These results demonstrate that two sequence and functional related enzymes are exported by distinct protein transport systems, which may play an integral role in the bacterial adaptation to their environment during the evolution. 相似文献
958.
Azotobacter vinelandii aldehyde dehydrogenase regulated by sigma(54): role in alcohol catabolism and encystment
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Gama-Castro S Núñez C Segura D Moreno S Guzmán J Espín G 《Journal of bacteriology》2001,183(21):6169-6174
Encystment in Azotobacter vinelandii is induced by n-butanol or beta-hydroxybutyrate (BHB). We identified a gene, encoding an aldehyde dehydrogenase, that was named aldA. An aldA mutation impaired bacterial growth on n-butanol, ethanol, or hexanol as the sole carbon source. Expression of aldA increased in cells shifted from sucrose to n-butanol and was shown to be dependent on the alternative sigma(54) factor. A mutation in rpoN encoding the sigma(54) factor also impaired growth on alcohols. Encystment on n-butanol, but not on BHB, was impaired in aldA or rpoN mutants, indicating that n-butanol is not an inducer of encystment by itself but must be catabolized in order to induce encystment. 相似文献
959.
960.
Encinar JA Mallo GV Mizyrycki C Giono L Gonzalez-Ros JM Rico M Cánepa E Moreno S Neira JL Iovanna JL 《The Journal of biological chemistry》2001,276(4):2742-2751
We have studied the biochemical features, the conformational preferences in solution, and the DNA binding properties of human p8 (hp8), a nucleoprotein whose expression is affected during acute pancreatitis. Biochemical studies show that hp8 has properties of the high mobility group proteins, HMG-I/Y. Structural studies have been carried out by using circular dichroism (near- and far-ultraviolet), Fourier transform infrared, and NMR spectroscopies. All the biophysical probes indicate that hp8 is monomeric (up to 1 mm concentration) and partially unfolded in solution. The protein seems to bind DNA weakly, as shown by electrophoretic gel shift studies. On the other hand, hp8 is a substrate for protein kinase A (PKA). The phosphorylated hp8 (PKAhp8) has a higher content of secondary structure than the nonphosphorylated protein, as concluded by Fourier transform infrared studies. PKAhp8 binds DNA strongly, as shown by the changes in circular dichroism spectra, and gel shift analysis. Thus, although there is not a high sequence homology with HMG-I/Y proteins, hp8 can be considered as a HMG-I/Y-like protein. 相似文献