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71.
Shu Pei Wang Nancy Laurin Jean Himms‐Hagen Michael A. Rudnicki Emile Levy Marie‐France Robert Linghe Pan Luc Oligny Grant A. Mitchell 《Obesity (Silver Spring, Md.)》2001,9(2):119-128
Objective: To directly ascertain the physiological roles in adipocytes of hormone‐sensitive lipase (HSL; E.C. 3.1.1.3), a multifunctional hydrolase that can mediate triacylglycerol cleavage in adipocytes. Research Methods and Procedures: We performed constitutive gene targeting of the mouse HSL gene (Lipe), subsequently studied the adipose tissue phenotype clinically and histologically, and measured lipolysis in isolated adipocytes. Results: Homozygous HSL?/? mice have no detectable HSL peptide or cholesteryl esterase activity in adipose tissue, and heterozygous mice have intermediate levels with respect to wild‐type and deficient littermates. HSL‐deficient mice have normal body weight but reduced abdominal fat mass compared with normal littermates. Histologically, both white and brown adipose tissues in HSL?/? mice show marked heterogeneity in cell size, with markedly enlarged adipocytes juxtaposed to cells of normal morphology. In isolated HSL?/? adipocytes, lipolysis is not significantly increased by β3‐adrenergic stimulation, but under basal conditions in the absence of added catecholamines, the lipolytic rate of isolated HSL?/? adipocytes is at least as high as that of cells from normal controls. Cold tolerance during a 48‐hour period at 4 °C was similar in HSL?/? mice and controls. Overnight fasting was well‐tolerated clinically by HSL?/? mice, but after fasting, liver triglyceride content was significantly lower in HSL?/? mice compared with wild‐type controls. Conclusions: In isolated fat cells, the lipolytic rate after β‐adrenergic stimulation is mainly dependent on HSL. However, the observation of a normal rate of lipolysis in unstimulated HSL?/? adipocytes suggests that HSL‐independent lipolytic pathway(s) exist in fat. Physiologically, HSL deficiency in mice has a modest effect under normal fed conditions and is compatible with normal maintenance of core body temperature during cold stress. However, the lipolytic response to overnight fasting is subnormal. 相似文献
72.
Philippe Le Flèche Yolande Hauck Lucie Onteniente Agnès Prieur France Denoeud Vincent Ramisse Patricia Sylvestre Gary Benson Françoise Ramisse Gilles Vergnaud 《BMC microbiology》2001,1(1):2-14
Background
Some pathogenic bacteria are genetically very homogeneous, making strain discrimination difficult. In the last few years, tandem repeats have been increasingly recognized as markers of choice for genotyping a number of pathogens. The rapid evolution of these structures appears to contribute to the phenotypic flexibility of pathogens. The availability of whole-genome sequences has opened the way to the systematic evaluation of tandem repeats diversity and application to epidemiological studies. 相似文献73.
A study of laboratory-reared larvae of Solea solea (Soleidae) and Scophthalmus maximus (Scophthalmidae) indicated that the epicranial portion of the dorsal fin results from the anterior displacement of proximal
pterygiophores during ontogeny. The adult epicranial formula is attained early during ontogeny, and the anterior displacement
is finalized after the passage of the migrating eye. In both species, the first two proximal pterygiophores fuse to form an
erisma that is particularly long and well-developed in Solea. Moreover, in Solea, the neural spine of the second abdominal vertebra curves over the otic region, and the neural arch of the first vertebra
remains incomplete.
Received: August 3, 2000 / Revised: August 10, 2001 / Accepted: October 12, 2001 相似文献
74.
75.
France Lelong 《Mathematical biosciences》1982,59(1):145-155
In a global pulmonary gas exchange model where global diffusion and ventilation are given, the effects of variations of local conductance?perfusion and ventilation?perfusion ratios on O2 concentration in arterial blood are studied. We give a special regard to the ability to get local maxima for this O2 concentration when the repartition of our parameters is heterogeneous. 相似文献
76.
Aurélien Sokal Pascal Chappert Giovanna Barba-Spaeth Anais Roeser Slim Fourati Imane Azzaoui Alexis Vandenberghe Ignacio Fernandez Annalisa Meola Magali Bouvier-Alias Etienne Crickx Asma Beldi-Ferchiou Sophie Hue Laetitia Languille Marc Michel Samia Baloul France Noizat-Pirenne Marine Luka Matthieu Mahévas 《Cell》2021,184(5):1201-1213.e14
77.
78.
79.
Robert L. France 《Hydrobiologia》1993,271(2):71-74
Hyalella azteca (Amphipoda) were sampled in eight Canadian Shield lakes, and the inter-relationships among life history traits were used
to determine the sensitivity of production and turnover rates to demographic variation. Production was positively related
to density and negatively related to both mortality and somatic growth. Turnover rates did not vary significantly with respect
to any demographic traits. Studies should advance from simply documenting production to instead describing ‘production ecology’
if an understanding of the environmental determinance of population regulation is desired. 相似文献
80.