Pathotypical characterization and molecular epidemiology of Newcastle disease virus isolates from different hosts in China from 1996 to 2005.
(33/135)
Thirty Newcastle disease virus (NDV) strains isolated from outbreaks in China during 1996 to 2005 were characterized pathotypically and genotypically. All strains except one were velogenic. An analysis of the variable region (nucleotides 47 to 420) of the F gene indicated that 6 isolates belonged to genotype II, 3 to genotype III, 1 (isolated from a pigeon) to genotype VI, and 20 to genotype VII. Isolates belonging to genotype VII were further divided into five subtypes, VIIa, VIIb, VIIc, VIId, and VIIe, and subtype VIId was made up of VIId1 to VIId5. These results showed that genotype VII isolates might have been the most prevalent in China during the past two decades. Genotype VII isolates shared high homology, but the homology was less than that between genotype VII viruses and the vaccine virus LaSota. Among these NDV isolates, 25 isolates had the velogenic motif (112)R/K-R-Q-K/R-R-F(117) that is consistent with results of the biological tests. However, four of five LaSota-type isolates that contained the lentogenic motif (112)G-R-Q-G-R-L(117) were velogenic, except SY/03, in the view of the biological test. The majority of genotype VII isolates had lost one or two N-glycosylation sites. Finally, a cross-protection experiment in which specific-pathogen-free chickens vaccinated with LaSota were challenged by six NDV isolates showed that more than three isolates were antigenic variants that could be responsible for recent outbreaks of Newcastle disease. (+info)
Energy saving processes in huddling emperor penguins: from experiments to theory.
(34/135)
This paper investigates the energy savings of male emperor penguins Aptenodytes forsteri linked to their huddling behaviour, the key factor that allows them to assume their incubating task while undergoing a long fast. Drawing on new studies by our team, this review examines the energetic benefits accrued from huddling and estimates the respective contributions of wind protection, exposure to mild ambient temperatures, reduction in cold-exposed body surfaces and body temperature adjustments in these energy savings. The metabolic rate of 'loosely grouped' birds (restrained in small groups of 5-10 individuals, which are unable to huddle effectively) is reduced by 39% compared to metabolic rate of 'isolated' birds, with 32% of these energetic benefits due to wind protection. In addition, metabolic rate of 'free-ranging' emperors, i.e. able to move freely and to huddle, is on average 21% lower than that of 'loosely grouped' birds. Exposure to mild ambient temperatures within the groups and reduction in cold-exposed body surfaces while huddling, though overestimated, would represent a 38% metabolic reduction. About two thirds of metabolic lowering is attributable to the reduction in cold-exposed body surfaces and one third to the mild microclimate created within the groups. Moreover, body temperature adjustments contribute to these energetic benefits: maintaining body temperatures 1 degrees C lower would represent a 7-17% reduction in energy expenditure. These processes, linked together, explain how huddling emperors save energy and maintain a constant body temperature, which ensures a successful incubation in the midst of the austral winter. (+info)
King penguin population threatened by Southern Ocean warming.
(35/135)
(+info)
Huddling: brown fat, genomic imprinting and the warm inner glow.
(36/135)
(+info)
Heart rate regulation and extreme bradycardia in diving emperor penguins.
(37/135)
(+info)
Bayesian inference of errors in ancient DNA caused by postmortem degradation.
(38/135)
(+info)
Long-term fasting decreases mitochondrial avian UCP-mediated oxygen consumption in hypometabolic king penguins.
(39/135)
(+info)
Osteology of Icadyptes salasi, a giant penguin from the Eocene of Peru.
(40/135)
(+info)