Inactivation of Mucor plumbeus by the combined actions of chitinase and high hydrostatic pressure

Sporangiospores were treated with high hydrostatic pressure and/or fungal chitinase in order to study the inhibition of germination and growth of the food spoiling mold Mucor plumbeus. Total fungal inhibition was obtained either at 4.0 kbar or by 10 U/ml of chitinase from Penicillium janthinellum. A pretreatment with 1 U/ml of the same chitinase reduced the pressure necessary to obtain complete spore inhibition to 3 kbar.     

上海金地三林城住宅区售楼中心

对于大多数住宅楼盘的开而言．售楼中心是必不可少的。当大部分住宅单元售出．售楼中心也就完成了它的历史使命，通常情况下或是被拆除，或是被改造为会所或社区中心，服务于新入住的居民。所以这类售楼中心的设计任务书常常显得很被动：一方面，开发商出于促销的需求，总是追求一个引人瞩目且散发着迷人光彩的地标性建筑.另一方面,过于紧迫的设计周期往往无法为设计师提供深入思考和高品质工作的空间，有关设计优化、生态环境考量和材料、细节研究等大多被忽略。     

Linker histone tails and N-tails of histone H3 are redundant: scanning force microscopy studies of reconstituted fibers

The mechanisms responsible for organizing linear arrays of nucleosomes into the three-dimensional structure of chromatin are still largely unknown. In a companion paper (Leuba, S. H., et al. 1998. Biophys. J. 74:2823-2829), we study the contributions of linker histone domains and the N-terminal tail of core histone H3 to extended chromatin fiber structure by scanning force microscopy imaging of mildly trypsinized fibers. Here we complement and extend these studies by scanning force microscopy imaging of selectively reconstituted chromatin fibers, which differ in subtle but distinctive ways in their histone composition. We demonstrate an absolute requirement for the globular domain of the linker histones and a structural redundancy of the tails of linker histones and of histone H3 in determining conformational stability.     

造福于人？还是造福于车？——上海新五角场不合理规划之我见

从2002年开始，上海杨浦区的五角场经历了一场重大变革。五条道路，立交桥，中环路，广场四周的大部分建筑，全部焕然一新。当施工途中所有脚手架、喧闹和灰尘逐渐退场，一个锃光瓦亮的街区登台了。一切都是崭新干净的，让人心旷神怡的，当然，因为它刚刚建成。人们纷纷赶来体验一把新开张的零售饮食门店，走一走新铺的步行街。民意调查显示，大部分民众觉得满意，因为新的五角场给杨浦区带来一种欣欣向荣的景象，一派西方式的富足画面。     

Histones H1 and H5 interact preferentially with crossovers of double-helical DNA

The interaction of the linker histones H1 and H5 from chicken erythrocyte chromatin with pBR322 was studied as a function of the number of superhelical turns in circular plasmid molecules. Supercoiled plasmid DNA was relaxed with topoisomerase I so that a population with a narrow distribution of topoisomers, containing from zero to five superhelical turns, was obtained. None of the topoisomers contained alternative non-B-DNA structures. Histone-DNA complexes formed at either 25 or 100 mM NaCl final concentration and at histone-DNA molar ratios ranging from 10 to 150 were analyzed by agarose gel electrophoresis. The patterns of disappearance of individual topoisomer bands from the gel were interpreted as an indication of preference of the linker histones for crossovers of double-helical DNA. This preference was observed at both salt concentrations, being more pronounced under conditions of low ionic strength. Isolated H5 globular domain also caused selective disappearance of topoisomers from the gel, but it did so only at very high peptide-DNA molar ratios. The observed preference of the linker histones for crossovers of double-helical DNA is viewed as a part of the mechanism involved in the sealing of the two turns of DNA around the histone octamer.     

Quantitative distribution of parvalbumin, calretinin, and calbindin D-28k immunoreactive neurons in the visual cortex of normal and Alzheimer cases

The distribution of parvalbumin (PV), calretinin (CR), and calbindin (CB) immunoreactive neurons was studied with the help of an image analysis system (Vidas/Zeiss) in the primary visual area 17 and associative area 18 (Brodmann) of Alzheimer and control brains. In neither of these areas was there a significant difference between Alzheimer and control groups in the mean number of PV, CR, or CB immunoreactive neuronal profiles, counted in a cortical column going from pia to white matter. Significant differences in the mean densities (numbers per square millimeter of cortex) of PV, CR, and CB immunoreactive neuronal profiles were not observed either between groups or areas, but only between superficial, middle, and deep layers within areas 17 and 18. The optical density of the immunoreactive neuropil was also similar in Alzheimer and controls, correlating with the numerical density of immunoreactive profiles in superficial, middle, and deep layers. The frequency distribution of neuronal areas indicated significant differences between PV, CR, and CB immunoreactive neuronal profiles in both areas 17 and 18, with more large PV than CR and CB positive profiles. There were also significantly more small and less large PV and CR immunoreactive neuronal profiles in Alzheimer than in controls. Our data show that, although the brain pathology is moderate to severe, there is no prominent decrease of PV, CR and CB positive neurons in the visual cortex of Alzheimer brains, but only selective changes in neuronal perikarya.     

Linker histone protects linker DNA on only one side of the core particle and in a sequence-dependent manner

The protection against micrococcal nuclease digestion afforded to chromatosomal DNA by the presence of a linker histone (H1(o)) has been quantitatively measured in two reconstituted systems. We have used chromatosomes reconstituted at two distinct positions on a DNA fragment containing the 5S rRNA gene from Lytechinus variegatus and at a specific position on a sequence containing Gal4- and USF-binding sites. In all cases, we find asymmetric protection, with approximately 20 bp protected on one side of the core particle and no protection on the other. We demonstrated through crosslinking experiments that the result is not due to any sliding of the histone core caused by either linker histone addition or micrococcal nuclease cleavage. Because the core particle is itself a symmetric object, the preferred asymmetric location of a linker histone must be dictated by unknown elements in the DNA sequence.     

Military are essential.

In his outburst against Meredith Crawford's (1970) article on military psychology (see record 1970-17677-001), M. J. Saks (see record 1990-56844-001) quotes from the APA's Ethical Standards: the psychologist "protects the welfare of any person who may seek his service . . . ." He then claims that "military psychology is clearly in conflict" with this principle. Saks is, of course, entitled to his personal opinion. But evidence is amply at hand to indicate that he does not represent the overwhelming majority of his fellow citizens who believe that the military are essential for the defense of their welfare in the present-day world. In their opinion, military psychology would further, rather than violate, the above-quoted principle. It would seem wise, therefore, to express gratitude to Crawford and military psychology for the aid they give in making our armed forces more efficient in protecting the welfare of the United States. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contributions of linker histones and histone H3 to chromatin structure: scanning force microscopy studies on trypsinized fibers

Little is known about the mechanisms that organize linear arrays of nucleosomes into the three-dimensional structures of extended and condensed chromatin fibers. We have earlier defined, from scanning force microscopy (SFM) and mathematical modeling, a set of simple structural determinants of extended fiber morphology, the critical parameters being the entry-exit angle between consecutive linkers and linker length. Here we study the contributions of the structural domains of the linker histones (LHs) and of the N-terminus of histone H3 to extended fiber morphology by SFM imaging of progressively trypsinized chromatin fibers. We find that cleavage of LH tails is associated with a lengthening of the internucleosomal center-to-center distance, and that the somewhat later cleavage of the N-terminus of histone H3 is associated with a flattening of the fiber. The persistence of the "zigzag" fiber morphology, even at the latest stages of trypsin digestion, can be attributed to the retention of the globular domain of LH in the fiber.