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991.
Rensing SA Lang D Zimmer AD Terry A Salamov A Shapiro H Nishiyama T Perroud PF Lindquist EA Kamisugi Y Tanahashi T Sakakibara K Fujita T Oishi K Shin-I T Kuroki Y Toyoda A Suzuki Y Hashimoto S Yamaguchi K Sugano S Kohara Y Fujiyama A Anterola A Aoki S Ashton N Barbazuk WB Barker E Bennetzen JL Blankenship R Cho SH Dutcher SK Estelle M Fawcett JA Gundlach H Hanada K Heyl A Hicks KA Hughes J Lohr M Mayer K Melkozernov A Murata T Nelson DR Pils B Prigge M Reiss B Renner T Rombauts S Rushton PJ 《Science (New York, N.Y.)》2008,319(5859):64-69
We report the draft genome sequence of the model moss Physcomitrella patens and compare its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison reveals genomic changes concomitant with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments (e.g., flagellar arms); acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provides a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics. 相似文献
992.
993.
Coral reefs are considered to be a source of atmospheric carbon dioxide because of their high calcium carbonate production and low net primary production. This was tested by direct measurement of diurnal changes in the partial pressure of carbon dioxide (Pco(co2)) in reef waters during two 3-day periods, one in March 1993 and one in March 1994, on Shiraho reef of the Ryukyu Islands, Japan. Although the Pco(co2) values in reef waters exhibited large diurnal changes ranging from 160 to 520 microatmospheres, they indicate that the reef flat area is a net sink for atmospheric carbon dioxide. This suggests that the net organic production rate of the reef community exceeded its calcium carbonate production rate during the observation periods. 相似文献
994.
Mice were injected with a monoclonal antibody to interferon-gamma to examine the importance of endogenous production of this lymphokine in resistance against infection with the sporozoan parasite Toxoplasma gondii. Mice with intraperitoneal infections of T. gondii that received no antibody survived and developed chronic T. gondii infection, whereas the infected mice that received the monoclonal antibody died of toxoplasmosis. The activation of macrophages, which kill T. gondii in vivo, was inhibited by administration of the monoclonal antibody, but the production of antibodies to T. gondii was not suppressed. The fact that an antibody to interferon-gamma can eliminate resistance to acute Toxoplasma infection in mice suggests that this lymphokine is an important mediator of host resistance to this parasite. 相似文献
995.
K Suzuki 《Science (New York, N.Y.)》1969,163(862):81-82
Giant mitochondria in hepatocytes that have the average size of nuclei can be consistently produced in the liver of weanling mice by feeding them cuprizone (bis-cyclohexanone oxaldihydrazone). The simplicity of the procedure and the consistency of the results make the feeding of cuprizone a new and useful experimental tool for the study of mitochondrial metabolism. 相似文献
996.
Anthony Winson 《Agriculture and Human Values》2008,25(4):499-511
To understand the phenomenon of the rapidly increasing prevalence of overweight and obese children and youth, it is especially
important to examine the school food environment, the role of structural factors in shaping this environment, and the resulting
nutrition and health outcomes. The paper examines research on school food environments in the US and Canada. It notes evidence
of widespread availability of poor nutrition products in both environments and delineates reasons for the situation, and examines
initiatives presently being undertaken in a number of jurisdictions in both countries to encourage healthy eating in schools.
Empirical data are presented from a pilot study of high schools in the Canadian province of Ontario. The study documents the
extent of student purchasing of nutrient-poor foods and beverages, and the structural factors internal and external to the
school that appear responsible for the availability of such products in food environments in this critical institutional sphere.
The paper also examines positive local initiatives in high schools that seek to encourage healthy eating in schools.
Anthony Winson PhD is a professor in the department of sociology and anthropology at the University of Guelph. He has written on agriculture, food and rural development, and restructuring issues related to Canada and the Third World for more than 20 years. Among his books are The Intimate Commodity: Food and the Development of the Agro-Industrial Complex in Canada (Garamond 1993) and, more recently, Contingent Work, Disrupted Lives (University of Toronto 2002, with Belinda Leach) which examines economic restructuring, the changing world of work, and the factors underlying sustainability in small manufacturing-dependent rural communities in several regions of Ontario. This book won the John Porter Book Prize of the Canadian Sociology and Anthropology Association for 2003. Dr. Winson’s current work is focused on the analysis of factors shaping the contemporary Canadian food environment and their role in producing what has been termed the “epidemic of obesity.” Particular attention is being paid to supermarkets and schools as part of broader-ranging research on the political economic context of the food environment. 相似文献
Anthony WinsonEmail: |
Anthony Winson PhD is a professor in the department of sociology and anthropology at the University of Guelph. He has written on agriculture, food and rural development, and restructuring issues related to Canada and the Third World for more than 20 years. Among his books are The Intimate Commodity: Food and the Development of the Agro-Industrial Complex in Canada (Garamond 1993) and, more recently, Contingent Work, Disrupted Lives (University of Toronto 2002, with Belinda Leach) which examines economic restructuring, the changing world of work, and the factors underlying sustainability in small manufacturing-dependent rural communities in several regions of Ontario. This book won the John Porter Book Prize of the Canadian Sociology and Anthropology Association for 2003. Dr. Winson’s current work is focused on the analysis of factors shaping the contemporary Canadian food environment and their role in producing what has been termed the “epidemic of obesity.” Particular attention is being paid to supermarkets and schools as part of broader-ranging research on the political economic context of the food environment. 相似文献
997.
Furuike S Hossain MD Maki Y Adachi K Suzuki T Kohori A Itoh H Yoshida M Kinosita K 《Science (New York, N.Y.)》2008,319(5865):955-958
F1-adenosine triphosphatase (ATPase) is an ATP-driven rotary molecular motor in which the central gamma subunit rotates inside a cylinder made of three alpha and three beta subunits alternately arranged. The rotor shaft, an antiparallel alpha-helical coiled coil of the amino and carboxyl termini of the gamma subunit, deeply penetrates the central cavity of the stator cylinder. We truncated the shaft step by step until the remaining rotor head would be outside the cavity and simply sat on the concave entrance of the stator orifice. All truncation mutants rotated in the correct direction, implying torque generation, although the average rotary speeds were low and short mutants exhibited moments of irregular motion. Neither a fixed pivot nor a rigid axle was needed for rotation of F1-ATPase. 相似文献
998.
Molecular cloning of the Bombyx mori prothoracicotropic hormone 总被引:17,自引:0,他引:17
A Kawakami H Kataoka T Oka A Mizoguchi M Kimura-Kawakami T Adachi M Iwami H Nagasawa A Suzuki H Ishizaki 《Science (New York, N.Y.)》1990,247(4948):1333-1335
Prothoracicotropic hormone (PTTH), a brain secretory polypeptide of insects, stimulates the prothoracic glands to produce and release ecdysone, the steroid essential to insect development. The complementary DNAs encoding PTTH of the silkmoth Bombyx mori were cloned and characterized, and the complete amino acid sequence was deduced. The data indicated that PTTH is first synthesized as a 224-amino acid polypeptide precursor containing three proteolytic cleavage signals. The carboxyl-terminal component (109 amino acids) that follows the last cleavage signal represents one PTTH subunit. Two PTTH subunits are linked together by disulfide bonds, before or after cleavage from prepro-PTTH, to form a homodimeric PTTH. When introduced into Escherichia coli cells, the complementary DNA directed the expression of an active substance that was functionally indistinguishable from natural PTTH. In situ hybridization showed the localization of the prepro-PTTH mRNA to two dorsolateral neurosecretory cells of the Bombyx brain. 相似文献
999.
Diana Stuart 《Agriculture and Human Values》2008,25(2):177-181
I explore the role of nature in the agrifood system and how attempts to fit food production into a large-scale manufacturing
model has lead to widespread outbreaks of food borne illness. I illustrate how industrial processing of leafy greens is related
to the outbreak of E. coli 0157:H7 associated with spinach in the fall of 2006. I also use this example to show how industry attempts to create the
illusion of control while failing to address weaknesses in current processing systems. The leafy greens industry has focused
efforts on sterilizing the growing environment and adopting new technologies, while neglecting to change the concentrated
structure of processing systems. Repeated breakdowns in these systems illustrate a widening fault line between attempted and
failed control of nature in industrial food production.
相似文献
Diana StuartEmail: |
1000.
Differentiation of immature mucous cells into parietal, argyrophil, and chief cells in stomach grafts 总被引:2,自引:0,他引:2
Microscopic and submicroscopic studies on regenerating gastric mucosa neonatally grafted in the subcutaneous tissue of littermate mice have revealed that immature mucous cells are totipotent; ultimately they transform into mature mucous, parietal, argyrophil, and chief cells in the gastric glands. 相似文献