While the incorporation of the transition proteins and protamines is the most overt change occurring during the re-packing of the spermatid DNA, there are other more subtle changes in histone composition and their post-translational modifications, including the hyperacetylation of histone H4.
Some studies (Hoang-Xuan et al, 2004; Ricard et al, 2007) have suggested that chemotherapy may affect tumour burden without causing overt morphological modifications that can be visualised by MRI, possibly by affecting the sole infiltrative part of the glioma.
Looking at these results from the viewpoint of the more traditional associative learning literature, the delivery of monetary rewards seems to affect VSA in ways that are similar to those available for the modification of overt behavior (e.g., [38] [41]).
Indeed, we additionally observed that 17 homozygous strains deleted for ubiquitin-modification genes had overt fitness defects during fermentation, a significant enrichment of this functional class of genes (Table 2).
In contrast to CIS, overt germ cell tumours derived from CIS cells seem to have acquired variable epigenetic modifications.
Although studies of the general population show that intensive modification of diet and physical activity can prevent or delay progression of prediabetes to overt type 2 diabetes mellitus, the question of whether NODAT can be prevented using a similar strategy has not, to our knowledge, been tested.
Some recently published trials also indicated that lifestyle modification and various pharmacological agents can delay or prevent the development of glucose disturbances to overt diabetes.
Life style modification, and the use of drugs such as metformin and acarbose can slow down progression to overt diabetes and/or cardiovascular disease in these subjects [32].
We observed no changes in total histone protein levels, and no overt, global changes in chromatin structure as measured cytologically in polytene chromosomes using antibodies that recognize a histone modification enriched in euchromatin or heterochromatin.
