Soil Conservation Management System for Beef Production in the Blacklands of Texas.

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Budding Yeast Chromosome Structure and Dynamics during Mitosis

Using green fluorescent protein probes and rapid acquisition of high-resolution fluorescence images, sister centromeres in budding yeast are found to be separated and oscillate between spindle poles before anaphase B spindle elongation. The rates of movement during these oscillations are similar to those of microtubule plus end dynamics. The degree of preanaphase separation varies widely, with infrequent centromere reassociations observed before anaphase. Centromeres are in a metaphase-like conformation, whereas chromosome arms are neither aligned nor separated before anaphase. Upon spindle elongation, centromere to pole movement (anaphase A) was synchronous for all centromeres and occurred coincident with or immediately after spindle pole separation (anaphase B). Chromatin proximal to the centromere is stretched poleward before and during anaphase onset. The stretched chromatin was observed to segregate to the spindle pole bodies at rates greater than centromere to pole movement, indicative of rapid elastic recoil between the chromosome arm and the centromere. These results indicate that the elastic properties of DNA play an as of yet undiscovered role in the poleward movement of chromosome arms

UNICELL ONTOGENY and PHYLOGENY: EXAMPLES FROM THE DIATOMS

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72275/1/j.1096-0031.1987.tb00511.x.pd

The Body in Allison Bechdel\u27s Fun Home

In “The Laugh of the Medusa,” Hélène Cixous stresses the importance of women writing their bodies, especially their sexuality, into their texts. Allison Bechdel writes her sexuality onto the pages of Fun Home, by literally depicting herself masturbating and having sex with her partner in college. As Cixous implies, Bechdel’s writing of her bodily experience allows her to identify herself as an adult, lesbian academic. But, what about a woman with many bodies? In a YouTube video titled “OCD”, Bechdel explains that her writing prosses involves physically posing as each character before she draws them, meaning that every image of a person within the text is an image of Bechdel. By analyzing a few problematic images in the text, such as the open cadaver in the funeral home, the photograph of a naked teenager, the exterior shot of Allison and her family, and the second full page panel of Allison in the car with her dad, the reader can see how Bechdel writes her body onto the page in a way that-instead of identifying who she is- complicates the reader’s perception of her. Thus, Bechdel shows how complicated identity is for a queer woman with anxiety and problematic family history

Organization of spindle microtubules in Ochromonas danica.

The entire framework of microtubules (MTs) in the mitotic apparatus of Ochromonas danica is reconstructed (except at the spindle poles) from transverse serial sections. Eleven spindles were sectioned and used for numerical data, but only four were reconstructed: a metaphase, an early anaphase, a late anaphase, and telophase. Four major classes of MTs are observed: (a) free MTs (MTs not attached to either pole); (b) interdigitated MTs (MTs attached to one pole which laterally associate with MTs from the opposite pole); (c) polar MTs (MTs attached to one pole); (d) kinetochore MTs (kMTs). Pole-to-pole MTs are rare and may be caused by tracking errors. During anaphase, the kMTs, free MTs, and polar MTs shorten until most disappear, while interdigitated MTs lengthen. In the four reconstructed spindles, the number of MTs decreases between early anaphase and telophase from 881 to 285, while their average length increases from 1.66 to 4.98 micron. The total length of all the MTs in the spindle (placed end to end) remains at 1.42 +/- 0.04 mm between these stages. At late anaphase and telophase the spindle is comprised mainly of groups of interdigitated MTs. Such MTs from opposite poles form a region of overlap in the middle of the spindle. During spindle elongation (separation of the poles), the length of the overlap region does not decrease. These results are compatible with theories that suggest that MTs directly provide the force that elongates the spindle, either by MT polymerization alone or by MT sliding with concomitant MT polymerization