Search results for "Ducks"
showing 10 items of 12 documents
THE BEHAVIORAL RESPONSE OF AMPHIPODS HARBORING CORYNOSOMA CONSTRICTUM (ACANTHOCEPHALA) TO VARIOUS COMPONENTS OF LIGHT
2006
Many studies have shown that photic behavior of amphipods is subject to parasitic manipulation. However, all these investigations have focused on but one property of light (i.e., intensity). This study investigated the possibility that variable wavelength sensitivity, as a potentially important component of amphipod ecology, is subject to parasitic manipulation. The photic behavior of freshwater amphipods Hyalella azteca, infected with the duck acanthocephalan Corynosoma constrictum, was tested. The phototactic responses of infected and uninfected amphipods to various wavelengths in the visible spectrum were compared, and to delineate the effects of intensity and wavelength on behavior, the…
Presence of plastic particles in waterbirds faeces collected in Spanish lakes
2017
Plastic intake by marine vertebrates has been widely reported, but information about its presence in continental waterfowl is scarce. Here we analyzed faeces of waterbirds species (European coot, Fulica atra, mallard, Anas platyrhynchos and shelduck, Tadorna tadorna) for plastic debris in five wetlands in Central Spain. We collected 89 faeces of shelduck distributed in four lakes, 43.8% of them presented plastic remnants. Sixty percent of 10 faeces of European coot and 45% of 40 faeces of mallard contained plastic debris. Plastic debris found was of two types, threads and fragments, and were identified as remnants of plastic objects used in agricultural fields surrounding the lakes. Differe…
Chlorinated hydrocarbons and total mercury in the prey of the white-tailed eagle (Haliaeetus albicilla L.) in the quarken straits of the gulf of both…
1976
Samples of the white-tailed eagle population and its prey were collected from the Quarken straits area of the Gulf of Bothnia, Finland, and were analyzed for DDT, DDD, PCBs, aldrin, lindane, and mercury. Mercury, PCB, and DDE were detected in all animals studied. It was concluded that one of the most important reasons for the poor breeding results of the white-tained eagle (especially hatchability) are the combined effects of the studied pollutants originating for the most part from the fish-eating species in its prey (mergansers and great crested grebes). (JTE)
Overexpression of STAT-1 by adenoviral gene transfer does not inhibit hepatitis B virus replication.
2006
Objectives Interferons are known to inhibit the replication of hepatitis B viruses (HBV) in several animal models in vitro and in vivo as well in humans. The STAT-1 protein plays a central role in the biological activity of both type I and type II interferons. The lack of functional STAT-1 renders cells and organisms susceptible to bacterial and viral infectious agents. We analysed whether the overexpression of STAT-1 protein enhances the biological interferon response and whether it elicits antiviral acitivity against HBV in vitro. Methods To achieve an efficient STAT-1 overexpression in primary liver cells and hepatoma cells, we generated a recombinant, replication-deficient adenovirus ex…
Effects of photodynamic processes and ultraviolet light on duck and hen egg-white lysozymes.
1973
— The photochemical yields for inactivation and amino acid destruction in hen and duck egg-white lysozyme are presented. Duck lysozyme II is devoid of histidine but it has two more tyrosine residues than does hen lysozyme. The data indicate that sensitized oxidation of the single histidine residue of hen lysozyme is of no significance for the inactivation of this lysozyme. The ultraviolet destruction of tryptophan and cystine residues appears to be equally related with the loss in enzymatic activity of hen lysozyme. In the case of duck lysozyme, however, the ultraviolet inactivation appears to be predominantly governed by the destruction of cystine residues.
Correlates of lifetime reproductive success in three species of European ducks
2003
Number of breeding attempts is a strong correlate of lifetime reproductive success (LRS) in birds, but the relative importance of potentially interacting factors affecting LRS has rarely been fully evaluated. We considered simultaneously five main factors hypothesized to influence LRS (age at first breeding, nesting date, number of breeding attempts, female traits, brood parasitism) by analyzing with path analysis 22-year data sets for 1,279 individually marked females and their offspring in tufted duck ( Aythya fuligula), common pochard ( A. ferina) and northern shoveler (Anas clypeata). We recaptured marked offspring as breeding adults (n=496 females) and obtained more complete estimates …
Acetylcholine overflow from isolated perfused hearts of various species in the absence of cholinesterase inhibition
1977
1. The content of acetylcholine in the tissue and effluent of isolated hearts of various birds and mammals was determined in the absence of inhibition of cholinesterase. 2. Stimulation of both vagus nerves for 15 min at 20 Hz caused marked negative chronotropic effects in all species. Spontaneous or stimulation-induced overflow of acetylcholine into the effluents was not detected in mammals. In the avian heart, the order of spontaneous overflow was: duck = chicken > pigeon, whereas the order of evoked overflow was: chicken > pigeon > duck. The acetylcholine overflow from the cat heart was below the limit of estimation (3 pmol g−1 min−1). In the chicken heart, the evoked overflow per min (28…
Status of Corynosoma (Acanthocephala: Polymorphidae) based on anatomical, ecological, and phylogenetic evidence, with the erection of Pseudocorynosom…
2006
The possession of genital spines has been considered as a key taxonomic trait to differentiate Corynosoma from other genera of the Polymorphidae. However, Corynosoma currently consists of 2 groups of species with clear ecological and morphological divergences: the "marine" group (with ca. 30 species) infects mammals and piscivorous birds in the marine realm, whereas the "freshwater" group (with ca. 7 species) infects waterfowl in continental waters. Species from these groups differ in shape of body and neck, trunk spination, lemnisci length and shape, testes arrangement, and number and shape of cement glands. We tested whether species from these 2 groups formed a monophyletic assemblage bas…
Forebrain specialization and the olfactory system in anseriform birds. An architectonic and tracing study.
1992
In anseriform birds the mediodorsal part of the rostral forebrain is covered by a corticoid (= layered) structure, establishing a unique feature of this avian group since in other birds the non-cortical accessory or dorsal hyperstriatum occupies the corresponding surface area of the hemisphere. The efferents of the olfactory bulb are shown to reach this region, which thus can be identified as a heavily enlarged retrobulbar area. The large expansion of this olfactory representation may indicate an important biological function. In comparison to the mammalian olfactory system the three stratified olfactory projection centers of birds should be regarded as retrobulbar, prepiriform and periamyg…
Examination of Escherichia coli from poultry for selected adhesin genes important in disease caused by mammalian pathogenic E. coli
2001
A collection of 1601 extraintestinal and intestinal Escherichia coli isolated from chickens, turkeys and ducks, in Belgium, France and Spain, was hybridised with gene probes specific for fimbrial and afimbrial adhesins (F17, F18, SSfa/F1C, Bfp, Afa, Cs31A, IntiminEae, Aida-1) of intestinal, urinary and invasive E. coli of mammals and with a probe specific for the P (Pap/Prs) fimbrial adhesin of urinary and invasive E. coli of mammals and birds. Three hundred and eighty-three strains (23.9%) were P-positive, 76 strains (4.8%) were Afa-positive, 75 strains (4.7%) were F17-positive, 67 strains (4.2%) were S-positive, 23 (1.4%) were Intimin-positive, and all were F18-, Cs31A-, Aida1- and Bfp-ne…