Parental care and clutch sizes in North and South American birds     

Martin TE  Martin PR  Olson CR  Heidinger BJ  Fontaine JJ 《Science (New York, N.Y.)》2000,287(5457):1482-1485

The evolutionary causes of small clutch sizes in tropical and Southern Hemisphere regions are poorly understood. Alexander Skutch proposed 50 years ago that higher nest predation in the south constrains the rate at which parent birds can deliver food to young and thereby constrains clutch size by limiting the number of young that parents can feed. This hypothesis for explaining differences in clutch size and parental behaviors between latitudes has remained untested. Here, a detailed study of bird species in Arizona and Argentina shows that Skutch's hypothesis explains clutch size variation within North and South America. However, neither Skutch's hypothesis nor two major alternatives explain differences between latitudes.  相似文献   

Menin controls growth of pancreatic beta-cells in pregnant mice and promotes gestational diabetes mellitus     

Karnik SK  Chen H  McLean GW  Heit JJ  Gu X  Zhang AY  Fontaine M  Yen MH  Kim SK 《Science (New York, N.Y.)》2007,318(5851):806-809

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Fungi mediate long term sequestration of carbon and nitrogen in soil through their priming effect     

S. Fontaine  C. Henault  N. Bdioui  V. Maire  S. Revaillot 《Soil biology & biochemistry》2011,43(1):86-96

It is increasingly recognized that soil microbes have the ability to decompose old recalcitrant soil organic matter (SOM) by using fresh carbon as a source of energy, a phenomena called priming effect (PE). However, efforts to determine the consequences of this PE for soil carbon and nitrogen dynamics are in their early stage. Moreover, little is known about the microbial populations involved. Here we explore the consequences of PE for SOM dynamics and mineral nitrogen availability in a soil incubation experiment (161 days), combining the supply of dual-labeled (¹³C and ¹⁴C) cellulose and mineral nutrients. The microbial groups involved in PE were investigated using molecular fingerprinting techniques (FAMEs and B- and F-ARISA). We show that mean residence time of SOM pool controlled by the PE decreased from 3130 years in the subsoil, where the availability of fresh carbon is very low, to 17-39 years in the surface layer. This result suggests that the decomposition of this recalcitrant soil C pool is strictly dependent on the presence of fresh C and is not an energetically viable mean of accessing C for soil microbes. We also suggest that fungi are the predominant actors of cellulose decomposition and induced PE and they adjust their degradation activity to nutrient availability. The predominant role of fungi can be explained by their ability to grow as mycelium which allows them to explore soil space and mine large reserve of SOM. Finally, our results support the existence of a bank mechanism that regulates nutrient and carbon sequestration in soil: PE is low when nutrient availability is high, allowing sequestration of nutrients and carbon; in contrast, microbes release nutrients from SOM when nutrient availability is low. This bank mechanism may help to synchronize the availability of soluble nutrients to plant requirement and contribute to long-term SOM accumulation in ecosystems.  相似文献   

Echinoderms: an autoradiographic study of assimilation of dissolved organic molecules     

Fontaine AR  Chia FS 《Science (New York, N.Y.)》1968,161(3846):1153-1155

In a holothurian and an ophiuroid, tritiated glucose and glycine in great dilution are removed from seawater by uptake through the skin. Cells differ in their competence to metabolize specific nutrients, an indication that there are specialized cellular responses to exogenous organic molecules. Embryonic ophiuroid tissues have an exceptional capacity for assimilation.  相似文献   

LYCOPERSICIN,A FUNGISTATIC AGENT FROM THE TOMATO PLANT     

Irving GW  Fontaine TD  Doolittle SP 《Science (New York, N.Y.)》1945,102(2636):9-11

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Involvement of sex steroids in final stages of oogenesis in Eurasian perch, Perca fluviatilis     

P. Fontaine  H. Migaud  R. Mandiki  J.N. Gardeur  P. Kestemont  A. Fostier 《Fish physiology and biochemistry》2003,28(1-4):331-332

Significant plasma 17,20β-dihydroxy-4-pregnen-3-one peaks were measured for the first time in female Eurasian perch, Perca fluviatilis, during the pre-ovulatory period, reaching 3.5 ng ml^?1, but was not synchronized with final maturation and ovulation stages.  相似文献   

Dose tapering for ciclosporin in cats with nonflea‐induced hypersensitivity dermatitis     

Jean Steffan  Elizabeth Roberts  Andrea Cannon  Pascal Prélaud  Peter Forsythe  Jacques Fontaine  Stephen King  Wolfgang Seewald 《Veterinary dermatology》2013,24(3):315-e70

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Identifying factors which maximise the lambing performance of hoggets: a cross sectional study     

PR Kenyon  GL Pinchbeck  NR Perkins  ST Morris  DM West 《New Zealand veterinary journal》2013,61(6):371-377

AIM: To identity perceptions of farmers with respect to advantages of hogget lambing and to identify optimal management strategies for hogget lambing used in New Zealand.

METHODS: A questionnaire was sent to 1,038 sheep farmers in New Zealand who had indicated their hoggets would be lambing in 2002. Information was gathered on the practice of hogget lambing in New Zealand, in particular on the numbers and breeds of hoggets and rams used, selection criteria used for hoggets, use of teasers (vasectomised rams), length of mating period, use of mating crayons, vaccinations, medications and mineral supplements given, level of feed offered, use of pregnancy scanning, management during pregnancy and lambing, number of lambs present at docking, and shearing policies for hoggets. Farmers were also asked to indicate the relative importance of five stated reasons for choosing to have their hoggets mated in 2002.

RESULTS: A total of 629 (60.6%) responses were incorporated in the analysis, and the average percentage of hogget lambing was 60%. Use of vaccinations, length of the mating period, number of rams used, breed of hogget, weight at mating, management during lactation, and shearing policy were associated (p<0.05) with the lambing performance of hoggets, in the multivariate analysis.

CONCLUSIONS: This study indicated that to ensure high lambing percentages (LP) in hoggets in New Zealand, sheep farmers should: vaccinate hoggets against toxoplasmosis and campylobacteriosis; utilise a 40-day mating period; use 2.6–3.5% of rams during mating; incorporate Finn or East Friesian genetics; ensure liveweights at mating are as high as possible; manage single- and multiple-bearing/-rearing hoggets separately during the lambing and lactation periods; and shear hoggets pre-mating.  相似文献   

Exophtalmie et rhabdomyosarcome orbitaire chez un chien     

V. Meunier  A. Fontaine  S. Leconte  F. Delisle  I. Raymond-Letron 《Pratique Médicale et Chirurgicale de l'Animal de Compagnie》2010,45(3):101-106

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Canine cutaneous epitheliotropic T‐cell lymphoma: a review of 30 cases     

Jacques Fontaine  Marianne Heimann  Michael J. Day 《Veterinary dermatology》2010,21(3):267-275

This retrospective study reviewed the clinical, histological and immunohistochemical features of 30 European cases of canine cutaneous epitheliotropic T‐cell lymphoma (CETL). The clinical presentation was highly variable and was not associated with the disease subtype. Diffuse erythema (86.6%) with scaling (60%) and focal hypopigmentation (50%) were the most common lesions. The skin was uniformly involved but muco‐cutaneous junctions or mucosae were affected in 50% of cases. The median age at diagnosis was 10 years (SD 2.79, range 4–15) and the median time between onset and final diagnosis was 5 months (SD 3.79, range 0–12). Five cases occurred in Bichon Frises. There was no evidence of a previous history of chronic dermatitis in any cases. Histologically, the follicular epithelium was affected in 86.7% of cases. One case with mainly follicular disease was considered folliculotropic mycosis fungoides (MF), but no follicular mucinosis was observed. Epidermal Pautrier’s microabscesses were uncommon (23.3%). Sweat glands were infiltrated in 70% of cases. Immunohistochemistry confirmed T‐cell neoplasia in all cases. B cells infiltrated as individual cells or formed linear bands or ectopic follicles at the base of the neoplasm. Ki67 labelling revealed a range of proliferation indices but did not correlate with severity. A final diagnosis of classical MF was made in 40% of the dogs, MF d’emblé in 36.7%, generalized Pagetoid reticulosis in 20% and localized Pagetoid reticulosis in one case (Woringer–Kolopp Pagetoid reticulosis). The median survival time after diagnosis was 6 months and this did not change appreciably with therapy (lomustine or prednisolone).  相似文献