A compound ovary with open carpels in winteraceae (magnoliales): evolutionary implications     

Leroy JF 《Science (New York, N.Y.)》1977,196(4293):977-978

"Bubbia" perrieri, a primitive angiosperm collected once in 1909 in northwestern Madagascar, differs from all other members of its genus and family (Winteraceae) in its bicarpellate, unilocular ovary. Moreover, its inflorescences are terminal, and its development is partially sympodial. It therefore represents the survivor of a previously undetected evolutionary line that should be accorded at least subfamilial status. If so, Winteraceae might, more likely than previously, be considered as allied to Canellaceae, a group of primitive angiosperms that has an ovary of "Bubbia" perrieri type and is specialized in some other respects.  相似文献   

Multiple Ebola virus transmission events and rapid decline of central African wildlife     

Leroy EM  Rouquet P  Formenty P  Souquière S  Kilbourne A  Froment JM  Bermejo M  Smit S  Karesh W  Swanepoel R  Zaki SR  Rollin PE 《Science (New York, N.Y.)》2004,303(5656):387-390

Several human and animal Ebola outbreaks have occurred over the past 4 years in Gabon and the Republic of Congo. The human outbreaks consisted of multiple simultaneous epidemics caused by different viral strains, and each epidemic resulted from the handling of a distinct gorilla, chimpanzee, or duiker carcass. These animal populations declined markedly during human Ebola outbreaks, apparently as a result of Ebola infection. Recovered carcasses were infected by a variety of Ebola strains, suggesting that Ebola outbreaks in great apes result from multiple virus introductions from the natural host. Surveillance of animal mortality may help to predict and prevent human Ebola outbreaks.  相似文献   

A physical map of the 1-gigabase bread wheat chromosome 3B   总被引：2，自引：0，他引：2  

Paux E  Sourdille P  Salse J  Saintenac C  Choulet F  Leroy P  Korol A  Michalak M  Kianian S  Spielmeyer W  Lagudah E  Somers D  Kilian A  Alaux M  Vautrin S  Bergès H  Eversole K  Appels R  Safar J  Simkova H  Dolezel J  Bernard M  Feuillet C 《Science (New York, N.Y.)》2008,322(5898):101-104

As the staple food for 35% of the world's population, wheat is one of the most important crop species. To date, sequence-based tools to accelerate wheat improvement are lacking. As part of the international effort to sequence the 17-billion-base-pair hexaploid bread wheat genome (2n = 6x = 42 chromosomes), we constructed a bacterial artificial chromosome (BAC)-based integrated physical map of the largest chromosome, 3B, that alone is 995 megabases. A chromosome-specific BAC library was used to assemble 82% of the chromosome into 1036 contigs that were anchored with 1443 molecular markers, providing a major resource for genetic and genomic studies. This physical map establishes a template for the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes with a chromosome-based approach.  相似文献   

Genetic diversity, inbreeding and breeding practices in dogs: results from pedigree analyses   总被引：2，自引：0，他引：2  

Leroy G 《Veterinary journal (London, England : 1997)》2011,189(2):177-182

Pedigree analysis constitutes a classical approach for the study of the evolution of genetic diversity, genetic structure, history and breeding practices within a given breed. As a consequence of selection pressure, management in closed populations and historical bottlenecks, many dog breeds have experienced considerable inbreeding and show (on the basis of a pedigree approach) comparable diversity loss compared to other domestic species. This evolution is linked to breeding practices such as the overuse of popular sires or mating between related animals. The popular sire phenomenon is the most problematic breeding practice, since it has also led to the dissemination of a large number of inherited defects. The practice should be limited by taking measures such as restricting the number of litters (or offspring) per breeding animal.  相似文献   

Comparison of bovine rotavirus strains by plaque assay     

L. Dagenais  A. Schwers  P.P. Pastoret  P. Leroy 《Veterinary microbiology》1981,6(4):379-382

Using plaque assay on MA 104 cells, four strains of bovine rotavirus were compared: the attenuated American strain NCDV, and three virulent strains isolated in Canada (PQ) or in Belgium (S14 and S 77). The attenuated strain (NCDV) formed smaller plaques than the three others. The plaque size may thus be used as a marker for this strain. The Belgian strain S 77 formed the largest plaques and no significant differences could be found between the Canadian strain PQ and the second Belgian strain S 14. On BSC-1 cells, the Canadian strain PQ formed much smaller plaques than on MA 104 cells.  相似文献   

Immunisation with a combination of two complementary feline calicivirus strains induces a broad cross-protection against heterologous challenges     

Poulet H  Brunet S  Leroy V  Chappuis G 《Veterinary microbiology》2005,106(1-2):17-31

Feline calicivirus (FCV) is characterised by a high degree of antigenic variation potentially compromising vaccine efficacy. Inclusion of several FCV strains or antigens in current vaccines could be a means to improve protection against antigenically distinct isolates. This study evaluated the synergy between two FCV strains (FCVG1 and FCV431) by comparing immunity induced by either strain with that provided by a combination of the two strains against an heterologous challenge with antigenically distant FCV strains (FCV393 and FCV220). Thirty-two SPF kittens were randomly allocated to four groups of eight cats in each group. Groups B, C and D cats were vaccinated once subcutaneously with strains FCVG1, FCV431, and FCVG1 + FCV431, respectively. Each kitten received a total dose of 10(3.4) CCID50 of FCV. Control group A was not immunised. On day 31, four cats from each group were challenged oronasally with FCV220 and four cats with FCV393. Following challenge, the cats were monitored for clinical signs, viral shedding and antibody responses. FCV220 and FCV393 induced severe clinical signs in control cats typical of FCV infection. Immunisation with both strains mixed together induced higher neutralizing antibody titres against FCV220 and FCV393 strains on average. Protection was observed in all groups, however combination of the two strains resulted in a better clinical protection and reduction of virus shedding after heterologous challenge. A moderate correlation was observed between neutralizing antibody titres at the time of challenge and protection against clinical signs. These results indicated that vaccines combining antigens from different FCV strains may induce a broader heterologous protection.  相似文献   

Characteristics of Peri-urban Dairy Herds of Bobo-Dioulasso (Burkina Faso)   总被引：1，自引：1，他引：0  

Sidibe M  Boly H  Lakouetené T  Leroy P  Bosma RH 《Tropical animal health and production》2004,36(1):95-100

Peri-urban dairy cattle farms within 50 km of Bobo-Dioulasso were studied to assess herd type, disease incidence, management, feeding and breeding strategy. Out of 417 cattle farmers, 42% had dairy objectives and were studied. Among these peri-urban dairy farmers, 60% were settled, 36% semi-settled, and 4% transhumant. In total, they held 4558 dairy cows, of which 32% lactated during the study. The prevalence of mastitis (55%) increased (p<0.05) with herd size. Advanced strategies for supplementary feeding and breeding were most frequent in small herds (<30 cattle). None of the large herds (>60 cattle) had advanced breeding strategies. Bulls and cows were culled at younger ages in herds with better breeding strategy. Overall, this resulted in higher individual milk offtake in small herds (2.46 L/day) compared with large herds (1.25 L/day). Pure breeds were rarely used, and the presence of Bos taurus baoulé naturally selected for trypanotolerance was low. The prevalence of trypanosomosis (40%) in herds dominated by Bos indicus zebu and Méré (Zebu x Baoulé) is an argument for maintenance of biodiversity and selection of Baoulé for milk production.  相似文献   

Tackling the microbiome     

Hood L 《Science (New York, N.Y.)》2012,336(6086):1209

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Immunogenicity of eight Mycobacterium avium subsp. paratuberculosis specific antigens in DNA vaccinated and Map infected mice     

Roupie V  Viart S  Leroy B  Romano M  Trinchero N  Govaerts M  Letesson JJ  Wattiez R  Huygen K 《Veterinary immunology and immunopathology》2012,145(1-2):74-85

Mycobacterium avium subsp. paratuberculosis (Map), the etiological agent of chronic enteritis of the small intestine in domestic and wild ruminants, causes substantial losses to livestock industry. Control of this disease is seriously hampered by the lack of adequate diagnostic tools and vaccines. Here we report on the immunogenicity of eight Map specific antigens, i.e. MAP1693c, Ag3, MAP2677c (identified by post-genomic and immunoproteomic analysis of Map secretome) and Ag5, Ag6, MAP1637c, MAP0388 and MAP3743 (identified by bioinformatic in silico screening of the Map genome). Strong, antigen-specific IFN-γ responses were induced in mice vaccinated with plasmid DNA encoding MAP1693c, MAP1637c, MAP0388 and MAP3743. In contrast, T cell responses in Map infected mice were directed preferentially against Ag5 and to a lesser extent against MAP3743. None of the tested DNA vaccines conferred protection against subsequent challenge with Map.  相似文献   

Source relationships between streambank soils and streambed sediments in a mercury-contaminated stream     

Dickson  Johnbull O.  Mayes  Melanie A.  Brooks  Scott C.  Mehlhorn  Tonia L.  Lowe  Kenneth A.  Earles  Jennifer K.  Goñez-Rodriguez  Leroy  Watson  David B.  Peterson  Mark J. 《Journal of Soils and Sediments》2019,19(4):2007-2019

Purpose

In contaminated streams, understanding the role of streambank and streambed source contributions is essential to developing robust remedial solutions. However, identifying relationships can be difficult because of the lack of identifying signatures in source and receptor pools. East Fork Poplar Creek (EFPC) in Oak Ridge, TN, USA received historical industrial releases of mercury that contaminated streambank soils and sediments. Here, we determined relationships between the contaminated streambank soils and sand-sized streambed sediments.

Materials and methods

Field surveys revealed the spatial trends of the concentrations of inorganic total mercury (Hg) and methyl mercury (MeHg), Hg lability as inferred by sequential extraction, particle size distribution, and total organic carbon. Statistical tests were applied to determine relationships between streambank soil and streambed sediment properties.

Results and discussion

Concentrations of Hg in streambank soils in the upper reaches averaged 206 mg kg^?1 (all as dry weight) (n?=?457), and 13 mg kg^?1 in lower reaches (n?=?321), while sand-sized streambed sediments were approximately 16 mg kg^?1 (n?=?57). Two areas of much higher Hg and MeHg concentrations in streambank soils were identified and related to localized higher Hg concentrations in the streambed sediments; however, most of the streambank soils have similar Hg concentrations to the streambed sediments. The molar ratio of Hg to organic carbon, correlation between MeHg and Hg, and particle size distributions suggested similarity between the streambank soils and the fine sand-sized fraction (125–250 μm) collected from the streambed sediments. Mercury in the fine sand-sized streambed sediments, however, was more labile than Hg in the streambank soils, suggesting an in-stream environment that altered the geochemistry of sediment-bound Hg.

Conclusions

This study revealed major source areas of Hg in streambank soils, identified possible depositional locations in streambed sediments, and highlighted potential differences in the stability of Hg bound to streambank soils and sediments. This work will guide future remedial decision making in EFPC and will aid other researchers in identifying source–sink linkages in contaminated fluvial systems.

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