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1.
In vertebrates, sex is determined by a surprising variety of mechanisms. In many reptiles, the primary testis or ovary-determining trigger is regulated by egg incubation temperature. This temperature dependent sex determining (TSD) mechanism occurs in all crocodilians and marine turtles examined to date and is common in terrestrial turtles and viviparous lizards (Ewert et al. 1994. J Exp Zool 270:3-15; Lang and Andrews. 1994. J Exp Biol 270:28-44; Mrosovsky. 1994. J Exp Zool 270:16-27; Pieau. 1996. Bioessays 18:19-26; Viets et al. 1994. J Exp Zool 270:45-56; Wibbels et al. 1998. J Exp Zool 281:409-416). In contrast, sex in mammals and birds is determined chromosomally (CSD). Despite these differences, morphological development of the gonads in all these vertebrate groups appears to have been conserved through evolution. Therefore, the genetic mechanisms triggering sex determination appear not to have been conserved through evolution, although the basic genetic pathway controlling the morphological differentiation of the gonads appears to have been conserved.  相似文献   

2.
Objective: To examine the differential response of obesity‐ and diabetes‐related traits to a high‐ or low‐fat diet in LG/J and SM/J mice. We also examined food consumption in these strains. Research Methods and Procedures: Mice were placed on a high‐ or low‐fat diet after weaning. Animals were weighed once per week and subjected to glucose tolerance tests at 20 weeks. At sacrifice, fat pads and internal organs were removed along with serum samples. For food consumption, LG/J and SM/J mice of each sex were assigned to a high‐fat or low‐fat diet after reaching maturity. Mice were weighed three times per week, and food consumed was determined by subtraction. Results: LG/J animals consume more total food, but SM/J animals consume more food per gram of body weight. LG/J mice grow faster to 10 weeks but slower from 10 to 20 weeks, have higher cholesterol and free fatty acid levels, and have lower basal glucose levels and better response to a glucose challenge than SM/J mice. For most traits, SM/J mice respond more strongly to a high‐fat diet than LG/J mice, including body weight and growth, basal glucose levels, organ weights, fat distribution, and circulating triglycerides and cholesterol levels. Discussion: Obesity‐related phenotypes, as well as response to increased dietary fat, differ genetically between LG/J and SM/J and can, therefore, be mapped. This study indicates that the cross of SM/J and LG/J mice would be an excellent model system for the study of gene‐by‐diet interaction in obesity.  相似文献   

3.
Levels of the neural cell adhesion molecule N-CAM in muscle are regulated in parallel with the susceptibility of muscle to innervation: N-CAM is abundant on the surface of early embryonic myotubes, declines in level as development proceeds, reappears when adult muscles are denervated or paralyzed, and is lost after reinnervation (Covault, J., and J. R. Sanes, 1985, Proc. Natl. Acad. Sci. USA, 82:4544-4548). Here we used immunocytochemical methods to compare this pattern of expression with those of several other molecules known to be involved in cellular adhesion. Laminin, fibronectin, and a basal lamina-associated heparan sulfate proteoglycan accumulate on embryonic myotubes after synapse formation, and their levels change little after denervation. L1, J1, nerve growth factor-inducible large external protein, uvomorulin, and a carbohydrate epitope (L2/HNK-1) shared by several adhesion molecules are undetectable on the surface of embryonic, perinatal, adult, or denervated adult muscle fibers. Thus, of the molecules tested, only N-CAM appears on the surface of muscle cells in parallel with the ability of the muscle cell surface to accept synapses. However, four antigens--N-CAM, J1, fibronectin, and a heparan sulfate proteoglycan--accumulate in interstitial spaces near denervated synaptic sites; regenerating axons traverse these spaces as they preferentially reinnervate original synaptic sites. Of particular interest is J1, antibodies to which block adhesion of central neurons to astrocytes (Kruse, J., G. Keihauer, A. Faissner, R. Timpl, and M. Schachner, 1985, Nature (Lond.), 316:146-148). J1 is associated with collagen and other fibrils in muscle and thus may be an extracellular matrix molecule employed in both the central and peripheral nervous systems.  相似文献   

4.
《Luminescence》1997,12(1):21-31
The following abstracts were not received in time to be included in the published collection of abstracts (J Biolumin Chemilumin 1996: 11:231-65). The three papers that follow were unable to be presented at the symposium and have not been peer reviewed. The symposium proceedings were published in the volume Bioluminescence and Chemiluminescence: Molecular Reporting with Photons, edited by J W Hastings, L J Kricka and PE Stanley, Chichester: Wiley,1997. © 1997 John Wiley & Sons, Ltd.  相似文献   

5.
Freitag H  Balke M 《ZooKeys》2011,(136):47-82
Ancyronyx montanussp. n. is described based on adults and larvae, matched using their cox1 DNA sequence data. Larvae of six additional species of Ancyronyx Erichson, 1847 were also described here for the first time, aided by cox1 or cob data: Ancyronyx helgeschneideri Freitag & J?ch, 2007, Ancyronyx minerva Freitag & J?ch, 2007, Ancyronyx patrolus Freitag & J?ch, 2007, Ancyronyx procerus J?ch, 1994, Ancyronyx punkti Freitag & J?ch, 2007, Ancyronyx pseudopatrolus Freitag & J?ch, 2007. Ancyronyx procerus is newly recorded from the Philippines by a larval specimen from Busuanga island. The new species and larval stages are described in detail and illustrated by digital and SEM images. A key to the Ancyronyx larvae of Palawan and an updated checklist of Philippine Ancyronyx is provided.  相似文献   

6.
Unruly Complexity: Ecology, Interpretation, Engagement. Peter J. Taylor. Chicago: University of Chicago Press, 2005. 289 pp.  相似文献   

7.
Human cytomegalovirus UL25 codes for a structural phosphoprotein of 85 kDa (C. J. Baldick and T. Shenk, J. Virol. 70:6097-6105, 1996; M. C. Battista et al., J. Virol. 73:3800-3809, 1999). In this study we analyzed the intracellular and intraviral localization of pUL25 by confocal and immunoelectron microscopy and found that pUL25 is a component of the viral tegument and the dense body matrix, acquired during the late cytoplasmic phase of virus maturation.  相似文献   

8.
Chiung-Yu  Huang Xianghua  Luo 《Biometrics》2008,64(3):987-988
The Statistical Analysis of Recurrent Events (R. J. Cook and J. F. Lawless) Chiung‐Yu Huang and Xianghua Luo Introduction to Empirical Processes and Semiparametric Inference (M. R. Kosorok) Changyong Feng Uncertain Judgements: Eliciting Experts' Probabilities (A. O'Hagan, C. E. Buck, A. Daneshkhah, J. R. Eiser, P. H. Garthwaite, D. J. Jenkinson, J. E. Oakley, and T. Rakow) James M. Dickey Models for Intensive Longitudinal Data (T. A. Walls and J. L. Schafer, editors) Daniel Farewell Quantitative Environmental Risk Analysis for Human Health (R. A. Fjeld, N. A. Eisenberg, and K. L. Compton) Scott M. Bartell Reliable Reasoning: Induction and Statistical Learning Theory (G. Harman and S. Kulkarni) Oliver Schulte Modeling Infectious Diseases in Humans and Animals (M. J. Keeling and P. Rohani) Carol Y. Lin Cluster and Classification Techniques for the Biosciences (A. H. Fielding) Morven Leese Modern Applied U‐Statistics (J. Kowalski and X. M. Tu) Jesse Frey Handbook of Statistical Genetics, 3rd edition (D. J. Balding, M. Bishop, and C. Cannings, editors) Karin Bammann, Ronja Foraita, Frauke Günther Quality of Life: The Assessment, Analysis, and Interpretation of Patient‐Reported Outcomes, 2nd edition (P. M. Fayers and D. Machin) Jeff A. Sloan, Amylou Dueck, Rui Qin, Wenting Wu, Pamela J. Atherton, Paul Novotny, Heshan Liu, Kelli N. Burger, Angelina D. Tan, Daniel Szydlo, Victor M. Johnson, Sara J. Felten, Xinghua Zhao, and Brent Diekmann Advanced Distance Sampling: Estimating Abundance of Biological Populations (S. T. Buckland, D. R. Anderson, K. P. Burnham, J. L. Laake, C. L. Borchers, and L. Thomas) Carl James Schwarz Brief Reports by the Editor The Construction of Optimal Stated Choice Experiments: Theory and Methods (D. J. Street and L. Burgess) Design and Analysis of Experiments, Volume 1: Introduction to Experimental Design, 2nd edition (K. Hinkelmann and O. Kempthorne) Introduction to Bayesian Statistics, 2nd edition (W. M. Bolstad) Asymptotic Theory of Statistics and Probability (A. Dasgupta) Bootstrap Methods: A Guide for Practitioners and Researchers, 2nd edition (M. R. Chernick)  相似文献   

9.
The high‐Andean genus Jivarus Giglio‐Tos from Ecuador, Colombia and Peru is revised. Morphological cladistic analysis indicated that Jivarus montanus and the new species digiticercus sp.n. and rugosus sp.n. must be treated as a separate genus, Maylasacris gen.n. The remaining species included in the analysis are assigned to the genus Jivarus, for which the following six species groups are identified: americanus group, antisanae group, carbonelli group, cohni group, pictifrons group and jagoi group. Twenty‐nine species are recognized for Jivarus, with ten described as new: J. rectus sp.n. , J. megacercus sp.n. , J. spatulus sp . n. , J. auriculus sp.n. , J. riveti sp.n. , J. sphaericus sp.n. , J. discoloris sp . n. , J. profundus sp.n. , J. ronderosi sp.n. and J. guarandaensis sp.n. The following new synonymies are proposed: Jivarus albolineatus Ronderos with J. antisanae (Bolivar) syn.n. , J. cerdai Ronderos and J. osunai Ronderos with J. alienus (Walker) syn.n. , and J. rubriventris Ronderos with J. ecuadorica (Hebard) syn.n. ; the new combinations Jivarus ecuadorica (Ronderos) comb.n. and Maylasacris montanus (Ronderos) comb.n. are proposed. Keys to the species of the genera and a review of the morphological characters defining the taxa are provided. Patterns of distribution of the clades coincide with the geography of the northern Andes of Colombia and Ecuador. Areas of endemism of the Jivarus species groups and Maylasacris are delimited by both the high‐altitude curves, including transverse zones, and the drier climates of the intra‐Andean valleys, clearly indicating recent, post‐glacial palaeogeography, as shown also in vegetation distributions. This paper has been formatted with many embedded links to images of type and paratype specimens, maps based on geo‐referenced specimen data and species keys available on the Orthoptera Species file online ( http://orthoptera.speciesfile.org ).  相似文献   

10.
Crafts, Capitalism, and Women: The Potters of La Chamba, Colombia. Ronald J. Duncan. Gainesville: University Press of Florida, 2000. 253 pp.  相似文献   

11.
12.
Human Adaptability: Past, Present, and Future. Stanley J. Ulijaszek and Rebecca A. Huss-Ashmore. eds. New York: Oxford University Press, 1997.326 pp.  相似文献   

13.
H M Lim  J J Pne    R W Shaw 《Journal of bacteriology》1988,170(6):2873-2878
Two forms of heat-stable, zinc-containing beta-lactamase II have been described for strains of Bacillus cereus and have been shown to differ in substrate specificity (R. B. Davies, E. P. Abraham, J. Fleming, and M. R. Pollock, Biochem. J. 145: 409-411, 1975). We report here the nucleotide sequence, inferred amino acid sequence, and expression of beta-lactamase II from B. cereus 5/B/6 and compare our results with those for its homolog characterized in B. cereus 569/H (M. Hussain, C. Anthony, M. J. Madonna, and J. O. Lampen, J. Bacteriol. 164: 223-229, 1985) to document amino acid differences contributing to the specific properties of these enzymes.  相似文献   

14.
Cystocarpic branches of a species of Gracilaria from Coquimbo, Chile, were cultured in vitro. A Polysiphonia-like life history was completed in about 6 months, but some abnormalities were observed: i. carpospores gave rise to plants producing either tetrasporangia and spermatangia, or tetrasporangia only; ii. tetraspores cultured without aeration developed into plants bearing spermatangia only; tetraspores cultured with aeration developed into 1:1 female and male gametophytes; iii. plant originated from tetraspore produced spermatangia and tetrasporangia; one of these tetraspores developed into a male gametophyte; iv. some tetraspores gave rise to spherical bodies instead of the ordinary cylindrical branches; one of them bore spermatangia after three months. The results show that environmental factors seem to be interfering with the mechanism of sex determination and induce the development of spermatangia on putative female gametophytes, or on putative tetrasporophytes. Noted added in proof: The Gracilaria sp. studied here was recently described as a new species, G. chilensis by Bird C. J., McLachlan, J & Oliveira, E. C. de, 1986. Can. J. Bot. 64: 2928–2934. Noted added in proof: The Gracilaria sp. studied here was recently described as a new species, G. chilensis by Bird C. J., McLachlan, J & Oliveira, E. C. de, 1986. Can. J. Bot. 64: 2928–2934.  相似文献   

15.
We analyzed the production of Torpedo marmorata acetylcholinesterase (AChE) in transfected COS cells. We report that the presence of an aspartic acid at position 397, homologous to that observed in other cholinesterases and related enzymes (Krejci, E., N. Duval, A. Chatonnet, P. Vincens, and J. Massoulié. 1991. Proc. Natl. Acad. Sci. USA. 88:6647-6651), is necessary for catalytic activity. The presence of an asparagine in the previously reported cDNA sequence (Sikorav, J.L., E. Krejci, and J. Massoulié. 1987. EMBO (Eur. Mol. Biol. Organ.) J. 6:1865-1873) was most likely due to a cloning error (codon AAC instead of GAC). We expressed the T and H subunits of Torpedo AChE, which differ in their COOH-terminal region and correspond respectively to the collagen-tailed asymmetric forms and to glycophosphatidylinositol-anchored dimers of Torpedo electric organs, as well as a truncated T subunit (T delta), lacking most of the COOH-terminal peptide. The transfected cells synthesized similar amounts of AChE immunoreactive protein at 37 degrees and 27 degrees C. However AChE activity was only produced at 27 degrees C and, even at this temperature, only a small proportion of the protein was active. We analyzed the molecular forms of active AChE produced at 27 degrees C. The H polypeptides generated glycophosphatidylinositol-anchored dimers, resembling the corresponding natural AChE form. The cells also released non-amphiphilic dimers G2na. The T polypeptides generated a series of active forms which are not produced in Torpedo electric organs: G1a, G2a, G4a, and G4na cellular forms and G2a and G4na secreted forms. The amphiphilic forms appeared to correspond to type II forms (Bon, S., J. P. Toutant, K. Méflah, and J. Massoulié. 1988. J. Neurochem. 51:776-785; Bon, S., J. P. Toutant, K. Méflah, and J. Massoulié. 1988. J. Neurochem. 51:786-794), which are abundant in the nervous tissue and muscles of higher vertebrates (Bon, S., T. L. Rosenberry, and J. Massoulié. 1991. Cell. Mol. Neurobiol. 11:157-172). The H and T catalytic subunits are thus sufficient to account for all types of known AChE forms. The truncated T delta subunit yielded only non-amphiphilic monomers, demonstrating the importance of the T COOH-terminal peptide in the formation of oligomers, and in the hydrophobic character of type II forms.  相似文献   

16.
Comment on: Bertran MT, et al. EMBO J 2011; 30:2634-47.  相似文献   

17.
The Rise and Fall of Culture History. R. Lee Lyman. Michael J. O'Brien. and Robert C. Dunnell. New York: Plenum Press, 1997.271pp.
Americanist Culture History: Fundamentals of Time, Space, and Form. R. Lee Lyman. Michael J. O'Brien. and Robert C. Dunnell. eds. New York: Plenum Press, 1997.499 p  相似文献   

18.
Contraception across Cultures: Technologies, Choices, Constraints. Andrew Russell. Elisa J. Sobo. and Mary S. Thompson. Oxford: Berg Publishers, 2000. 224 pp.  相似文献   

19.
Body Talk: Rhetoric, Technology, Reproduction. Mary M. Lay. Laura J. Gurak. Clare Gravon. and Cynthia Myntii. eds. Madison: University of Wisconsin Press, 2000. xiii. 307 pp.  相似文献   

20.
There are claims that phytohemagglutinin (PHA), the lectin of common bean, Phaseolus vulgaris, is toxic when fed to the cowpea weevil, Callosobruchus maculatus, and that PHA serves as the chemical defense against this seed-feeding bruchid beetle (DH Janzen, HB Juster, IE Liener [1976] Science 192: 795-796; AMR Gatehouse, FM Dewey, J Dove, KA Fenton, A Pusztai [1984] J Sci Food Agric 35: 373-380). However, our studies indicate that neither PHA nor its isolectins have detrimental effects when fed to the cowpea weevil. To explain these contradictory results we characterized the commercial lectin source used by A. M. R. Gatehouse, F. M. Dewey, J. Dove, K. A. Fenton, A. Pusztai (1984, J Sci Food Agric 35: 373-380). We demonstrate here that the toxic effects of PHA to cowpea weevil are due to an α-amylase inhibitor contaminant in the commercial preparation.  相似文献   

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