At the phylum level, members of Bacteroidetes were found at high levels in the severely autistic selleck inhibitor group, whereas members of Firmicutes were dominant in controls. At the species level, Desulfovibrio species and Bacteroides vulgatus occurred in significantly higher numbers in severely autistic children than in controls. Higher bacterial diversity was disclosed in the feces of autistic individuals when compared with controls. The authors emphasized that it remains uncertain whether autism leads to changes in the gut microbiota or the changed microbiota exerts any influence on the di
The cytoskeleton of adherent cells can organize into highly regular structures: Actin and myosin filaments can bundle into long fibers, and fibers can align parallel to each other (1), in a type of nematic ordering of the cytoskeleton (2,3).
In a variety of cell types, different kinds of acto-myosin bundles additionally possess periodic internal structure with alternating localization of myosin filaments and the actin cross-linker ��-actinin. Examples include striated stress fibers in fibroblasts (Fig. 1 A) and striated stress-fiber-like acto-myosin bundles in some developing muscle cells (Fig. 1 B) (4�C7). The striated architecture of these fibers has similarity to the sarcomeric architecture of myofibrils in striated muscle, but is much less regular. In both adherent, nonmuscle cells and developing striated muscle cells, the striations of neighboring, but distinct fibers are often in registry, i.e., the positions of the respective ��-actinin and myosin bands match (see Fig. 1, panel D versus panel C).
This interfiber registry of striated fibers represents a further state of cytoskeletal order, which we term ��smectic order�� in analogy to liquid crystal terminology. Figure 1 (A) Adherent, nonmuscle cells can exhibit striated stress fibers characterized by an alternating localization of the actin cross-linker ��-actin (green; light gray in print) and nonmuscle myosin II (red; dark gray in print); calyculin stimulated … Striated fibers in various types of muscle cells or those in nonmuscle cells can differ in their actin and myosin isoforms, and some scaffolding proteins like titin, nebulin, and N-RAP appear specific to muscle cells. Nevertheless, these striated fibers share important physical features that include a periodic architecture, stress generation via acto-myosin contractility, and some level of mechanical coupling to a substrate.
Thus, despite their different protein compositions, a common physical mechanism may guide interfiber registry in these different cases. Striated stress-fiber-like acto-myosin bundles, close to the plasma membrane of developing muscle Batimastat cells, have been proposed to be important intermediate structures in at least one pathway of myofibrillogenesis, i.e.