Sex-specific parental care in dimorphic species may be unsurprising, but why this occurs monomorphic is more puzzling. To date, however, there have been few examinations of the causes phenomenon. Here, we evaluated possible explanations sex-specific provisioning Leach's storm-petrel Hydrobates leucorhous (until recently Oceanodroma leucorhoa). We tracked chick-rearing behavior 74 mated pairs us...

there is nothing quite so helpless in this world as a baby broiler chick which has been snatched from the warmth of its surrogated mother, carted umpteen kilometers in a box dumped unceremoniously in a broiler shed and then told to get on with the job of making the boss a wealthy man. yet within the space of 14 days, that same chick, under optimum conditions, will have increased its day-old bod...

Maternal effects occur when the mother's phenotype influences her offspring's phenotype. In birds, differential allocation in egg yolk components can allow mothers to compensate for the competitive disadvantage of junior chicks. We hypothesize that the parent-older chick conflict peaks at intermediate conditions: parents benefit from the younger chick(s) survival, but its death benefits the old...

Chick embryonic stem cells (cESCs) can be derived from cells obtained from stage X embryos (blastoderm stage); these have the ability to contribute to all somatic lineages in chimaeras, but not to the germ line. However, lines of stem cells that are able to contribute to the germ line can be established from chick primordial germ cells (cPGCs) and embryonic germ cells (cEGCs). This review provi...

We previously reported that serum deprivation stimulates myofibrillar proteolysis in chick myotubes. In the present study, we examined the effect of serum deprivation on expression of the proteolytic-related genes (ubiquitin, proteasome, calpains, and cathepsin B) by real-time PCR of cDNA in chick myotubes. Myotubes were incubated with serum-free medium for 24 h. Ubiquitin and proteasome subuni...

Temperature-sensitive mutants of Sindbis virus were employed to investigate the nature of the viral event(s) which induces chick-embryo cells to produce interferon. Chick embryo cells induced by the parental heat-resistant strain of Sindbis virus produced essentially equal amounts of interferon at 29 and 42 C. An RNA(-) and three RNA(+) strains [temperature-sensitive mutants unable (RNA(-)) and...

Heating adenovirus types 8 and 12 for 2 to 3 min. at 560 simultaneously reduced both interferon-inducting capacity and infectivity. In contrast, virus inactivated by u.v.-irradiation effectively stimulated interferon production in chick cells. Chick cells infected with adenovirus type 12 and incubated at 25 °, 35 ° or 4 °o produced about the same amount of interferon but the kinetics of interfe...

The effect of unlabeled cellular DNA upon the reassociation kinetics of labeled double-stranded DNA made by DNA polymerase from avian tumor viruses has been used to measure virus-specific nucleotide sequences in cells. Multiple copies of these sequences were found equally in normal chick cells, in chick cells transformed in culture, and in Rous tumor cells. Copies were also present equally in c...

1. 72 hour isolated chick hearts show an increase in pulsation rate when placed in M/1000, M/10,000, and M/50,000 l-tyrosine solutions. The optimal effect is seen in M/10,000 and M/50,000 l-tyrosine. 2. All hearts show disturbance of rhythm either in the form of irregular rhythm or heart block. 3. 62 hour isolated chick hearts are not susceptible to l-tyrosine while 96 hour hearts are markedly ...

Changes in lectin activity during development of embryonic chick skin were studied. In the dorsal skin of the chick embryo in which feathers were formed, lectin activity first increased, during the period of dermal condensation, and then it decreased during the development of feathers. A similar change in lectin activity was also found in the anterior shank skin, the prospective scale region of...