Atomic force microscopy (AFM) provides a method for detecting nanoscale structural information. First, this review explains the fundamentals of AFM, including principle, manipulation, and analysis. Applications of AFM are then reported in food science and technology research, including qualitative macromolecule and polymer imaging, complicated or quantitative structure analysis, molecular interaction, molecular manipulation, surface topography, and nanofood characterization. The results suggested that AFM could bring insightful knowledge on food properties, and the AFM analysis could be used to illustrate some mechanisms of property changes during processing and storage. However, the current difficulty in applying AFM to food research is lacking appropriate methodology for different food systems. Better understanding of AFM technology and developing corresponding methodology for complicated food systems would lead to a more in-depth understanding of food properties at macromolecular levels and enlarge their applications. The AFM results could greatly improve the food processing and storage technologies.

No abstract

Spinocerebellar ataxia type 1 (SCA1) is one of nine inherited neurodegenerative disorders caused by a mutant protein with an expanded polyglutamine tract. Phosphorylation of ataxin‐1 (ATXN1) at serine 776 is implicated in SCA1 pathogenesis. Previous studies, utilizing transfected cell lines and a Drosophila photoreceptor model of SCA1, suggest that phosphorylating ATXN1 at S776 renders it less susceptible to degradation. This work also indicated that oncogene from AKR mouse thymoma (Akt) promotes the phosphorylation of ATXN1 at S776 and severity of neurodegeneration. Here, we examined the phosphorylation of ATXN1 at S776 in cerebellar Purkinje cells, a prominent site of pathology in SCA1. We found that while phosphorylation of S776 is associated with a stabilization of ATXN1 in Purkinje cells, inhibition of Akt either in vivo or in a cerebellar extract‐based phosphorylation assay did not decrease the phosphorylation of ATXN1‐S776. In contrast, immunodepletion and inhibition of cyclic AMP‐dependent protein kinase decreased phosphorylation of ATXN1‐S776. These results argue against Akt as the in vivo kinase that phosphorylates S776 of ATXN1 and suggest that cyclic AMP‐dependent protein kinase is the active ATXN1‐S776 kinase in the cerebellum.

-Impairment of skeletal muscle function has been associated with changes in ovarian hormones, especially estradiol. To elucidate mechanisms of estradiol on skeletal muscle strength, the hormone's effects on phosphorylation of the myosin regulatory light chain (pRLC) and muscle contractility were investigated, hypothesizing an estradiol-specific beneficial impact. In a skeletal muscle cell line, C 2C12, pRLC was increased by 17␤-estradiol (E 2) in a concentration-dependent manner. In skeletal muscles of C57BL/6 mice that were E 2 deficient via ovariectomy (OVX), pRLC was lower than that from ovary-intact, sham-operated mice (Sham). The reduced pRLC in OVX muscle was reversed by in vivo E 2 treatment. Posttetanic potentiation (PTP) of muscle from OVX mice was low compared with that from Sham mice, and this decrement was reversed by acute E 2 treatment, demonstrating physiological consequence. Western blot of those muscles revealed that low PTP corresponded with low pRLC and higher PTP with greater pRLC. We aimed to elucidate signaling pathways affecting E 2-mediated pRLC using a kinase inhibitor library and C 2C12 cells as well as a specific myosin light chain kinase inhibitor in muscles. PI3K/Akt, MAPK, and CamKII were identified as candidate kinases sensitive to E 2 in terms of phosphorylating RLC. Applying siRNA strategy in C 2C12 cells, pRLC triggered by E 2 was found to be mediated by estrogen receptor-␤ and the G protein-coupled estrogen receptor. Together, these results provide evidence that E 2 modulates myosin pRLC in skeletal muscle and is one mechanism by which this hormone can affect muscle contractility in females. estrogen; estrogen receptor; kinase; post tetanic potentiation; RLC OVARIAN HORMONE DEFICIENCY is related to muscle dysfunction and loss of strength. For example, declines in strength are accelerated around the time of menopause (35,41,51), and skeletal muscles of postmenopausal women on estrogen-based hormone therapy are stronger than those not on hormone therapy (10,17,49). In mouse models, contractile characteristics are impaired in muscles of ovariectomized compared with sham-operated mice (16,38,39,53,65). It was suggested (41) and subsequently demonstrated that ovarian hormones influence muscle strength by directly affecting the function of contractile proteins (43,66), particularly the structure and function of myosin (38,39). Among the ovarian hormones, 17␤-estradiol (E 2 ) appears to be the key hormone, because it reverses muscle weakness and contractile protein dysfunction caused by ovariectomy. Specifically, reduced muscle and contractile protein functions were restored when E 2 was administered to ovariectomized mice (16,38,53). In a chemical model of premature aging, of which the ovaries of young adult mice were locally and specifically induced to be senescent, E 2 treatment improved some muscle contractile functions (18). Although these studies have demonstrated that E 2 impacts muscle and myosin functions, the molecular mechanisms by which this hormone affects the structure a...

No abstract

No abstract

Background: Phosphorylation at Ser-776 of the polyglutamine disease-associated protein Ataxin-1 modulates its function.Results: 14-3-3 binding stabilizes Ataxin-1 by blocking dephosphorylation of pS776 and impedes Ataxin-1 transport to the nucleus.Conclusion: 14-3-3 must disassociate from Ataxin-1 for its transport to the nucleus.Significance: 14-3-3 regulates Ataxin-1 function by protecting phosphorylation of Ser-776 and Ataxin-1 entry into the nucleus.

No abstract