Host/parasite relationship in the in vitro infection of rat gliocytes by Neospora caninum: evaluation of cell respiration     

Pinheiro AM  Santos CV  Costa Mde F  Rodrigues LE 《Research in veterinary science》2007,83(1):27-29

Neospora caninum is a protozoon that causes abortion in cattle and neuromuscular lesions in dogs, with the formation of cysts mainly in the central nervous system. Since N. caninum is an intracellular parasite with tropism for the cells of nervous system, this study evaluated the respiratory metabolism of glial cells infected by this* parasite. Glial cultures obtained from the cerebral cortex of newborn rats were kept in DMEM enriched with 10% fetal bovine serum, 1 mM pyruvic acid and 2 mM of L-glutamine. They were infected at a ratio of approximately 1:1 (cell/parasite). Oxygen consumption was evaluated by polarography in the non infected and N. caninum infected groups, 24 and 72 h following infection. Glial cell respiration after 24 and 72 h was 307.2 +/- 34.7 and 308.9 +/- 64.1 microL of oxygen per mug of total protein per minute, and 566.2 +/- 54.6 and 579 +/- 117.5 microL O2/microg of total protein/minute in the control and infected groups, respectively. These results show that N. caninum does not interfere with glial respiration in vitro.  相似文献   

Variation of Phyllosphere Microflora of Different Rice Varieties in Sri Lanka and its Relationship to Leaf Anatomical and Physiological Characters   总被引：2，自引：0，他引：2  

D. M. De Costa  R. M. P. S. Rathnayake  W. A. J. M. De Costa  W. M. D. Kumari  D. M. N. Dissanayake 《Journal of Agronomy and Crop Science》2006,192(3):209-220

Anatomical and physiological characters of the leaf surface and its physico‐chemical environment substantially influence the density and diversity of phyllosphere‐inhabiting microorganisms, which may include natural antagonists of important pathogens. The objective of this investigation was to quantify the phyllosphere (i.e. leaf surface) microbial population in a range of rice varieties grown in Sri Lanka and to identify the leaf anatomical and physiological characters that determine the density and diversity of phyllosphere microbes. Fifteen rice varieties including both traditional and new high‐yielding varieties were used in a planthouse experiment and a field experiment in two consecutive seasons to quantify the phyllosphere microbial population and measure leaf characters that may influence it. There were highly significant intervarietal variations in the density and diversity of epiphytic bacterial, fungal and total microbial populations under both planthouse and field conditions. However, there was no difference between traditional and new, high‐yielding varieties in their capacity to harbour epiphytic microbes in the phyllosphere. Total microbial density (TMD) under both conditions showed positive correlations with leaf hair density, stomatal density and transpiration rate. Under planthouse conditions, TMD was also positively correlated with leaf hair length and negatively correlated with leaf temperature. These correlations can be explained in terms of providing favourable microsites on the phylloplane for epiphytic microbial growth.  相似文献   

Breeding Panicum maximum in Brazil. 1. Genetic resources,modes of reproduction and breeding procedures     

Y. H. Savidan  L. Jank  J. C. G. Costa  C. B. do Valle 《Euphytica》1989,41(1-2):107-112

Summary Apomixis is widely distributed among tropical forage grasses, and has long been merely regarded as an impediment to breeding. Panicum maximum is presented as the first opportunity for Brazilian geneticists to develop and test original breeding schemes adapted to an apomictic species.A large and representative germplasm of P. maximum has been introduced and is currently being evaluated. Basic knowledges on biology and reproduction are also available, which demonstrate an easy manipulation of apomixis and sexuality. Several limiting traits have already been detected during evaluation, which justify breeding attempts. An ideal scheme is given to transfer new qualities to already selected varieties.  相似文献   

Interaction of the mutant genes B,og c,hp and t in the coloring of tomato fruit     

Thiago Matos Andrade  Wilson Roberto Maluf  Celso Mattes de Oliveira  Luiz Antônio Augusto Gomes  Daniela Costa Santos  Regis de Castro Carvalho  Ranoel José de Sousa Gonçalves  Álvaro Carlos Gonçalves Neto 《Euphytica》2015,205(3):773-783

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Absorption of calcium fumarate salts is equivalent to other calcium salts when measured in the rat model   总被引：3，自引：0，他引：3  

Weaver CM  Martin BR  Costa NM  Saleeb FZ  Huth PJ 《Journal of agricultural and food chemistry》2002,50(17):4974-4975

Calcium absorption from fumarate salts (calcium fumarate and calcium malate fumarate), which have recently been considered for use as sources for food and beverage enrichment, was compared to that from calcium citrate malate, calcium citrate, and calcium carbonate. Salts were instrinsically labeled with 45Ca and orally administered to Sprague-Dawley rats. Fractional absorption of calcium from each salt was determined using the femur uptake model. Fractional absorption from the five salts (0.30-0.27) was not significantly different (p > 0.05). Thus, when measured in the rat model, calcium from calcium fumarate and calcium malate fumarate is absorbed equally well as compared to other salts, which are common calcium sources in many foods, beverages, and supplements.  相似文献   

Ecological effects of a major oil spill on panamanian coastal marine communities   总被引：1，自引：0，他引：1  

Jackson JB  Cubit JD  Keller BD  Batista V  Burns K  Caffey HM  Caldwell RL  Garrity SD  Getter CD  Gonzalez C  Guzman HM  Kaufmann KW  Knap AH  Levings SC  Marshall MJ  Steger R  Thompson RC  Weil E 《Science (New York, N.Y.)》1989,243(4887):37-44

In 1986 more than 8 million liters of crude oil spilled into a complex region of mangroves, seagrasses, and coral reefs just east of the Caribbean entrance to the Panama Canal. This was the largest recorded spill into coastal habitats in the tropical Americas. Many population of plants and animals in both oiled and unoiled sites had been studied previously, thereby providing an unprecedented measure of ecological variation before the spill. Documenation of the spread of oil and its biological begun immediately. Intertidal mangroves, algae, and associated invertebrates were covered by oil and died soon after. More surprisingly, there was also extensive mortality of shallow subtidal reef corals and infauna of seagrass beds. After 1.5 years only some organisms in areas exposed to the open sea have recovered.  相似文献   

Observation of X-ray lines from a gamma-ray burst (GRB991216): evidence of moving ejecta from the progenitor     

Piro L  Garmire G  Garcia M  Stratta G  Costa E  Feroci M  Mészáros P  Vietri M  Bradt H  Frail D  Frontera F  Halpern J  Heise J  Hurley K  Kawai N  Kippen RM  Marshall F  Murakami T  Sokolov VV  Takeshima T  Yoshida A 《Science (New York, N.Y.)》2000,290(5493):955-958

We report on the discovery of two emission features observed in the x-ray spectrum of the afterglow of the gamma-ray burst (GRB) of 16 December 1999 by the Chandra X-ray Observatory. These features are identified with the Ly(alpha) line and the narrow recombination continuum by hydrogenic ions of iron at a redshift z = 1.00 +/- 0.02, providing an unambiguous measurement of the distance of a GRB. Line width and intensity imply that the progenitor of the GRB was a massive star system that ejected, before the GRB event, a quantity of iron approximately 0.01 of the mass of the sun at a velocity approximately 0.1 of the speed of light, probably by a supernova explosion.  相似文献   

A molecular basis for natural selection at the timeless locus in Drosophila melanogaster     

Sandrelli F  Tauber E  Pegoraro M  Mazzotta G  Cisotto P  Landskron J  Stanewsky R  Piccin A  Rosato E  Zordan M  Costa R  Kyriacou CP 《Science (New York, N.Y.)》2007,316(5833):1898-1900

Diapause is a protective response to unfavorable environments that results in a suspension of insect development and is most often associated with the onset of winter. The ls-tim mutation in the Drosophila melanogaster clock gene timeless has spread in Europe over the past 10,000 years, possibly because it enhances diapause. We show that the mutant allele attenuates the photosensitivity of the circadian clock and causes decreased dimerization of the mutant TIMELESS protein isoform to CRYPTOCHROME, the circadian photoreceptor. This interaction results in a more stable TIMELESS product. These findings reveal a molecular link between diapause and circadian photoreception.  相似文献   

The ubiquitin ligase SCFFbw7 antagonizes apoptotic JNK signaling     

Nateri AS  Riera-Sans L  Da Costa C  Behrens A 《Science (New York, N.Y.)》2004,303(5662):1374-1378

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Comment on "Drought-induced reduction in global terrestrial net primary production from 2000 through 2009"     

Samanta A  Costa MH  Nunes EL  Vieira SA  Xu L  Myneni RB 《Science (New York, N.Y.)》2011,333(6046):1093; author reply 1093

Zhao and Running (Reports, 20 August 2010, p. 940) reported a reduction in global terrestrial net primary production (NPP) from 2000 through 2009. We argue that the small trends, regional patterns, and interannual variations that they describe are artifacts of their NPP model. Satellite observations of vegetation activity show no statistically significant changes in more than 85% of the vegetated lands south of 70°N during the same 2000 to 2009 period.  相似文献