The purposes of this study were to document the self-concept, cardiovascular endurance and isometric muscular strength of children with spina bifida, and to examine the changes in these variables in response to a structured 10-week exercise programme. Eight children trained for about 1 hour a week for 10 weeks, while the five control-group children did not participate in the physical-activity programme. The exercise group improved significantly on five of eight criterion means, while the control group showed no significant improvements. This programme represents an initial attempt to delineate the essential elements in a physical-activity programme to enhance physical fitness and self-concepts of children with spina bifida, and provides a framework for further study.

Adolescent↗

PubMedDate not supplied

Crystallographic studies of elongation factor G.

The elongation factors G (EF-G) and Tu (EF-Tu) go through a number of conformation states in their functional cycles. Since they both are GTPases, have similar G domains and domains II, and have similar interactions with the nucleotides, then GTP hydrolysis must occur in similar ways. The crystal structures of two conformational states are known for EF-G and three are known for EF-Tu. The conformations of EF-G.GDP and EF-Tu.GTP are closely related. EF-Tu goes through a large conformational change upon GTP cleavage. This conformational change is to a large extent due to an altered interaction between the G domain and domains II and III. A number of kirromycin-resistant mutations are situated at the interface between domains I and III. The interface between the G domain and domain V in EF-G corresponds with this dynamic interface in EF-Tu. The contact area in EF-G is small and dominated by interactions between charged amino acids, which are part of a system that is observed to undergo conformational changes. Furthermore, a number of fusidic acid resistant mutants have been identified in this area. All of this evidence makes it likely that EF-G undergoes a large conformational change in its functional cycle. If the structures and conformational states of the elongation factors are related to a scheme in which the ribosome oscillates between two conformations, the pretranslocational and posttranslocational states, a model is arrived at in which EF-Tu drives the reaction in one direction and EF-G in the opposite. This may lead to the consequence that the GTP state of one factor is similar to the GDP state of the other. At the GTP hydrolysis state, the structures of the factors will be close to superimposable.

Amino Acid Sequence↗

PubMedDate not supplied

[The effect of delta-ALK on the biosynthesis of cobamides and porphyrins by a culture of Actinomyces olivaceus].

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Iron↗