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921.
922.
Liana Tsiatsiani Evy Timmerman Pieter-Jan De Bock Dominique Vercammen Simon Stael Brigitte van de Cotte An Staes Marc Goethals Tine Beunens Petra Van Damme Kris Gevaert Frank Van Breusegem 《The Plant cell》2013,25(8):2831-2847
Metacaspases are distant relatives of the metazoan caspases, found in plants, fungi, and protists. However, in contrast with caspases, information about the physiological substrates of metacaspases is still scarce. By means of N-terminal combined fractional diagonal chromatography, the physiological substrates of METACASPASE9 (MC9; AT5G04200) were identified in young seedlings of Arabidopsis thaliana on the proteome-wide level, providing additional insight into MC9 cleavage specificity and revealing a previously unknown preference for acidic residues at the substrate prime site position P1′. The functionalities of the identified MC9 substrates hinted at metacaspase functions other than those related to cell death. These results allowed us to resolve the substrate specificity of MC9 in more detail and indicated that the activity of phosphoenolpyruvate carboxykinase 1 (AT4G37870), a key enzyme in gluconeogenesis, is enhanced upon MC9-dependent proteolysis. 相似文献
923.
An exhumed late Pleistocene land surface on the deltaic Sandai Plain north of Lake Bogoria, Kenya, preserves traces of bovids, suids, birds, and at least one hominid. The host sediments (Loboi Silts) are reddish brown, poorly bedded siltstones, mudstones and silty sandstones that were probably deposited in a shallow closed-basin lake. Most of the prints were impressed on exposed, moist lake-marginal mudflats. Print distribution is patchy due to a complex interaction between biogenic and sedimentological factors. The preservation of a single hominid track provides a fortuitous addition to the sparse hominid track record in East Africa. Field, petrographic, and mineralogical analyses of the fossil substrate were undertaken to determine how the footprinted surface was preserved. Comparison with modern lake-marginal processes suggests that the prints were initially stabilized by desiccation, soil-crusting, and organic films, followed by cementation of the surface sediments by calcite and analcime, with minor authigenic clay minerals and Fe-Mn-oxihydroxides. The zeolites formed by reaction of detrital silicates with saline, alkaline groundwater; calcite was precipitated from dilute runoff and fresher groundwaters. Cementation likely occurred during a prolonged period of relatively low, stable lake level. Following cementation, the surface was buried by Holocene lake sediments, then recently exhumed. 相似文献
924.
Michael J. Stewart Praphaporn Stewart Morakot Sroyraya Nantawan Soonklang Scott F. Cummins Peter J. Hanna Wei Duan Prasert Sobhon 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2013,164(2):276-290
The crustacean X-organ–sinus gland (XO–SG) complex controls molt-inhibiting hormone (MIH) production, although extra expression sites for MIH have been postulated. Therefore, to explore the expression of MIH and distinguish between the crustacean hyperglycemic hormone (CHH) superfamily, and MIH immunoreactive sites (ir) in the central nervous system (CNS), we cloned a CHH gene sequence for the crab Portunus pelagicus (Ppel-CHH), and compared it with crab CHH-type I and II peptides. Employing multiple sequence alignments and phylogenic analysis, the mature Ppel-CHH peptide exhibited residues common to both CHH-type I and II peptides, and a high degree of identity to the type-I group, but little homology between Ppel-CHH and Ppel-MIH (a type II peptide). This sequence identification then allowed for the use of MIH antisera to further confirm the identity and existence of a MIH-ir 9 kDa protein in all neural organs tested by Western blotting, and through immunohistochemistry, MIH-ir in the XO, optic nerve, neuronal cluster 17 of the supraesophageal ganglion, the ventral nerve cord, and cell cluster 22 of the thoracic ganglion. The presence of MIH protein within such a diversity of sites in the CNS, and external to the XO–SG, raises new questions concerning the established mode of MIH action. 相似文献
925.
A major difficulty in addressing chemical mixtures through legislation or regulations revolves around our limited understanding of their potential impacts. This review provides an overview of recent research on pesticide mixture toxicity to aquatic biota and the methods employed to predict toxic effects. The most common approaches are to assume concentration-addition or independent action of chemicals in a mixture. There are a number of cases in the literature of interactions between pesticides. However, models accounting for possible interactions between mixture components are used infrequently. Although results are limited, studies investigating the effects of pesticide mixtures have not demonstrated significant synergism at environmentally relevant concentrations. Based on the results of our review, we conclude that the concentration-addition model is a generally conservative and practical first-tier model for the ecological assessment of pesticide mixtures in aquatic systems. 相似文献
926.
S. E. Kornguth A. Flangas J. Perrin R. Geison G. Scott 《Preparative biochemistry & biotechnology》2013,43(2):167-192
Synaptic complexes were isolated from different brain regions and developmental stages in a CsCl density gradient using a Ti-14 zonal rotor. The buoyant density of the synaptic complexes from all these tissues was 1.178–1.190. The conditions for maximal resolution were rapid displacement of the density gradient from the rotor (40 ml/min); continuous centrifugation of the particles in the gradient for 66 hours, sample loads not exceeding 200 mg membrane protein. The banding densities of the membranes in the CsCl gradient were shown to be a linear inverse function of their lipid content. The circular dichroism patterns of synaptic complexes and other neural membranes in suspension or SDS solutions were similar to those of membranes from other mammalian cells or from bacteria although the ellipticities of the neural membranes were lower. These studies indicate that the proteins in a variety of membranes are in an α-helical conformation. 相似文献
927.
Neurons have highly specialized intracellular compartments that facilitate the development and activity of the nervous system. Ubiquitination is a post-translational modification that controls many aspects of neuronal function by regulating protein abundance. Disruption of this signaling pathway has been demonstrated in neurological disorders such as Parkinson’s disease, Amyotrophic Lateral Sclerosis and Angleman Syndrome. Since many neurological disorders exhibit ubiquitinated protein aggregates, the loss of neuronal ubiquitin homeostasis may be an important contributor of disease. This review discusses the mechanisms utilized by neurons to control the free pool of ubiquitin necessary for normal nervous system development and function as well as new roles of protein ubiquitination in regulating the synaptic activity. 相似文献
928.
929.
930.
Vincent?Koppelmans Burak?Erdeniz Yiri?E?De Dios Scott?J?Wood Patricia?A?Reuter-Lorenz Igor?Kofman Jacob?J?Bloomberg Ajitkumar?P?Mulavara Rachael?D?Seidler