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Full-Text Articles in Developmental Biology

The Homeo Domain Of A Murine Protein Binds 5' To Its Own Homeo Box., Abraham Fainsod, Leonard D. Bogarad, Tarmo Ruusala, Martin Lubin Dec 1986

The Homeo Domain Of A Murine Protein Binds 5' To Its Own Homeo Box., Abraham Fainsod, Leonard D. Bogarad, Tarmo Ruusala, Martin Lubin

Dartmouth Scholarship

Nuclear protein extracts from day 12.5 mouse embryos were used to study protein binding to DNA sequences 5' of the Hox 1.5 homeo box. Embryos of this developmental stage are known to express this gene. DNA binding protein blotting and retardation gel techniques show that murine embryonic nuclear proteins specifically bind a 753-base pair (bp) DNA fragment from the region upstream of the Hox 1.5 homeo box. A fusion protein containing the Hox 1.5 homeo domain constructed in lambda gt11 also binds the same 753-bp DNA fragment. Specific binding of the fusion protein to the upstream DNA fragment shows that …


Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois Dec 1986

Spermatogenesis And Histology Of The Testes Of The Caecilian, Chthonerpeton Indistinctum, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

Macroscopically, the testes of Chthonerpeton indistinctum consist of a series of oval lobes. The number and size of lobes is variable in Chthonerpeton indistinctum. Histologically, the testes are divided into structural units, locules separated by septa of connective tissue. Inside of each locule spermatogenesis takes place in cysts of germinal cells that divide synchronically. Chthonerpeton indistinctum is divided chronologically into four stages of development based on the shape of the nuclei of the spermatids and their arrangement in the cyst: (1) round, (2) kidney shaped, (3) attenuate, and (4) bouquet arrangement.


Variation In Piglet Weights: Development Of Within-Litter Variation Over A 5-Week Lactation And Effect Of Farrowing Crate Design, B. K. Thompson, D. Fraser Jun 1986

Variation In Piglet Weights: Development Of Within-Litter Variation Over A 5-Week Lactation And Effect Of Farrowing Crate Design, B. K. Thompson, D. Fraser

Ontogeny Collection

Piglets from 51 litters were weighed weekly over a 5-wk lactation in an experiment that studied the effects of farrowing crate design and other factors on variation in piglet weight. Of two farrowing crates used, one had low horizontal bars that tended to impede access to the upper row of teats, while the other had angled vertical bars which permitted freer access. Fourteen-day weights were more uniform in the vertical-bar crates than in the horizontal-bar crates (P < 0.025), but the difference waned by day 35 (P > 0.05). There were no significant differences in mean body weight owing to crate type (P < 0.05) for any of the weekly measurements but, by day 14, there was a significant linear trend (P < 0.05) at decreasing main body weight with increasing litter size. The interaction between crate type and litter size was significant at the later ages (P < 0.01 at day 35) because the linear trend was more pronounced for horizontal-bar crates than for vertical. Litters differed greatly in the uniformity of their body weights. Much of the variation became established in the first and, to a lesser extent, the second week after birth. In those weeks, weight gains were highly variable and were not closely related to weight at the beginning of the week. Thereafter, the established differences tended to be perpetuated to 35 d, because weight gains were largely proportional to body weight. Within-litter competition appeared to influence weight gain considerably.


Variation In Piglet Weights: Relationship To Suckling Behavior, Parity Number And Farrowing Crate Design, David Fraser, B. K. Thompson Mar 1986

Variation In Piglet Weights: Relationship To Suckling Behavior, Parity Number And Farrowing Crate Design, David Fraser, B. K. Thompson

Ontogeny Collection

Suckling behavior and weight change of piglets were studied during the first 2 wk after birth. Thirty-six litters comprised a balanced comparison of parity number (first or second), litter size (8, 10 or 12), and two farrowing crate designs, one of which had a low horizontal bar that tended to impede the piglets' access to the udder. Piglets showed the expected preference for the anterior teats although the preference was more apparent in the second parity than in the first. Teat fidelity was most pronounced at the two ends of the udder; piglets occupying the middle positions did more fighting …