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Biomedical subjects

D M Bird

Publications and source records attributed to D M Bird.

52 records · Page 3Linked to original sources
PubMed1988

dpy-13: a nematode collagen gene that affects body shape.

Mutations in the Caenorhabditis elegans dpy-13 (dumpy) gene result in a short, chunky body shape. This gene was tagged by insertion of the Tc1 transposon, and the wild-type gene was cloned by chromosomal walking 11 kb from ama-1, a cloned gene encoding the large subunit of RNA polymerase II. Three transposon insertion sites in dpy-13 are located near the 5' end of a 1.2 kb transcribed region. The EMS-induced reference allele, dpy-13(e184), carries a small deletion near the middle of this gene. The DNA sequence reveals that dpy-13 is a member of the collagen multi-gene family, and it could encode a polypeptide of 302 amino acids. A 146 base pair sequence, encoding amino acids 56-103, is unique in the C. elegans genome, and it hybridizes to a 1 kb mRNA of moderate abundance.

Alleles↗
PubMed1987

Influence of a diet of fluoride-fed cockerels on reproductive performance of captive American kestrels.

In 1982, twenty-four pairs of captive American kestrels (Falco sparverius) were forced to renest by removal of their first clutches 6 days after their completion. Immediately following, each of three groups of eight pairs was randomly assigned to one of three daily dietary regimes for 10 days: (1) three 1-day old cockerels with background levels of F(-) (62.4+/-51ppm, mean+/-SD) in their femurae, (2) two 10-day old cockerels with 4512+/-810ppm of F(-) in their femurae, (3) two 10-day old cockerels with 7690+/-417ppm of F(-) in their femurae. Fluoride levels in femurae of treated kestrels were significantly (P<0.0025) higher than those of control birds. Clutch sizes tended to be smaller as more fluoride was added to the diet, but not significantly so, due to an increase of the variance in the treatment group. Per cent fertility and per cent hatchability were not significantly affected by treatment. The fluoride content in eggshells in the fluoride-treated groups differed significantly from those of the control group (P<0.001).

Journal Article↗
PubMed1986

Variations in plasma corticosterone, estrone, estradiol-17 beta, and progesterone concentrations with forced renesting, molt, and body weight of captive female American kestrels.

Corticosterone, progesterone, estradiol-17 beta, and estrone were quantified in plasma collected weekly (April-September) from renesting and nonlaying female American kestrels (Falco sparverius) paired with males in captivity. Hormone levels and body weights for laying females were maximal during courtship and egg-laying periods, while those for non-layers showed no such distinct peaks. This demonstrated that these profiles were not controlled solely by photoperiod. Plasma corticosterone levels were elevated in all females during August and September when kestrels are preparing for migration. For laying females, body weight was positively correlated with plasma estrogen levels. A low spring body weight gain, and not stress, may have prevented the females from breeding in captivity. The photoperiodic control of molt did not appear to be mediated directly by the hormones studied, since there were no changes in hormone levels associated with the onset of molt.

Animals↗
PubMed1984

Simultaneous quantification of progesterone, estrone, estradiol-17 beta and corticosterone in female American kestrel plasma.

Progesterone, estrone, estradiol-17 beta and corticosterone were quantified simultaneously for the first time in female American kestrel (Falco sparverius) plasma. A mean level for each hormone was determined for the laying and non-laying periods of the summer (April-September), and for February. Means were comparable to those of other wild avian species and were significantly higher for the laying period than for the other 2 periods. The mean corticosterone level for February was higher than that for the non-laying summer period. Plasma from laying kestrels, unlike that from other avian species, required lipid removal before column chromatography. Of 2 lipid removal techniques compared, i.e. the cold methanol and hexane:methanol techniques, the latter proved superior.

Animals↗
PubMed1983

Plasma protein patterns in captive American kestrels.

Plasma proteins of the American kestrel (Falco sparverius) were analyzed by polyacrylamide disc electrophoresis for 3 different groups of birds: laying and non-laying females, and males. The electrophoretic patterns were homogeneous for each group and showed differences in the mobility of some proteins among the 3 groups. There was no significant difference among the 3 groups in the amount of proteins and in the standard parameter of albumin to globulin ratio.

Animals↗
PubMed1982

Variation in selected hematological parameters of captive red-tailed hawks.

Diurnal and winter variations of four hematological parameters were examined in 10 red-tailed hawks (Buteo jamaicensis). The mean values obtained were: 39.4% packed cell volume (PCV); 2.45 X 10(6) erythrocytes (RBC) per mm3 of blood; 5.73 mg of calcium and 1.44 mg of magnesium per 100 ml of plasma. Only the PCV and RBC count showed significant diurnal variation. When the birds were sampled at a set time of day, from November through to February, no significant changes were detected in any of the four parameters. Variation among the birds in RBC count, PCV and calcium concentration was significant on a diurnal basis but over the four month period only the PCV varied significantly.

Animals↗
PubMedDate not supplied

Effects of electromagnetic fields on the reproductive success of American kestrels.

Reduced reproductive success of birds nesting near power lines has been documented but never directly attributed to electromagnetic fields (EMFs). Laboratory studies have identified EMF effects on embryonic development, but reproductive success of wild birds is dependent on additional factors, including fertility, egg size, hatching, and fledging success. We tested whether EMFs affect reproductive success of birds. Captive American kestrels (Falco sparverius) were bred for one season per year for 2 yr under either controlled or EMF conditions. EMF exposure was equivalent to that experienced by wild reproducing kestrels and was weakly associated with reduced egg laying in 1 yr only. In both years fertility was higher, but hatching success was lower in EMF pairs than control pairs. Fledging success was higher in EMF pairs than control pairs in 1995 only. Egg composition and embryonic development were examined in 1 yr only, but hatchlings were measured in both years. EMF eggs were larger, with more yolk, albumen, and water, but had thinner egg shells than control eggs. Late-term EMF embryos were larger and longer than control embryos, although hatchlings were similar in body mass and size. EMF exposure affected reproductive success of kestrels, increasing fertility, egg size, embryonic development, and fledging success but reducing hatching success.

Animals↗
PubMedDate not supplied

DNA sequence and expression analysis of root-knot nematode-elicited giant cell transcripts.

Fifty-eight cDNA clones isolated from a library of transcripts exhibiting up regulation in tomato root giant cells induced by infection with the parasitic nematode Meloidogyne incognita were characterized. A survey of plant tissues identified 31 transcripts present in tissues other than root, including actively dividing and expanding tissues and mature leaf tissues. The identities of approximately 20% of the giant cell transcripts were inferred from DNA sequence data; they include sequences encoding a plasmalemma proton ATPase, a putative Myb-type transcription factor, and the largest subunit of RNA polymerase II.

Amino Acid Sequence↗