Synthesis and function of Actinomyces naeslundii T14V type 1 fimbriae require the expression of additional fimbria-associated genes

The nucleotide sequence of the chromosomal DNA flanking the Actinomyces naeslundii (formerly A. viscosus) T14V type 1 fimbrial structural subunit gene (fimP) was determined. Six open reading frames (ORFs), in the order 5' ORF3, ORF2, ORF1,fimP, ORF4, ORF5, ORF6 3', were identified. ORF1 encoded a protein of 408 amino acid residues (Mr = 39,270) and had significant sequence homology with the A. naeslundii T14V type 1 and A. naeslundii WVU45 type 2 fimbrial structural subunits. An in-frame fusion of ORF1 to the malE gene of the expression vector, pMAL-c2, yielded a protein that was immunostained with antibodies raised against the maltose binding protein and A. naeslundii T14V whole bacteria. Digestion of the fusion protein with factor Xa released a protein (apparent molecular mass of 34 kDa) that was immunostained only with the antibody directed against A. naeslundii T14V whole bacterial cells. Integration plasmids carrying a kanamycin resistance gene (kan) that was used to substitute for ORF1 or for DNA fragments internal to the coding region of the other five ORFs were used to transform A. naeslundii T14V. Neither type 1 fimbriae nor the 65-kDa fimbrial structural subunit was detected in mutants obtained by allelic replacement of ORF1 or ORF2. Mutants obtained by allelic replacement of ORF3 or ORF4 expressed only the 65-kDa fimbrial structural subunit. These mutants did not bind, in vitro, to proline-rich proteins that serve as the receptors for Actinomyces type 1 fimbriae. In contrast, a mutant in which the integration plasmid DNA had been inserted at a site close to the carboxyl terminus of ORF6 expressed type 1 fimbriae and had adherence properties similar to those observed in the wild-type strain. These results demonstrate the existence of additional genes near fimP that are likely to be involved in the synthesis and function of cell surface fimbriae of A. naeslundii T14V.     

Limits of accuracy of dyeing process control and dyeing quality

In this study, a previously-developed numerical prediction model of colour sensitivity for disperse dye recipes was applied to predict the limit of accuracy in the control of dyeing processes according to a certain colour tolerance for individual recipes. The results confirmed that both concentration and temperature were the most important factors affecting dyeing results.     

Heterogeneity of the T cell response to immunodominant determinants within hen eggwhite lysozyme of individual syngeneic hybrid F1 mice: implications for autoimmunity and infection

Hybrid F1 mice derived from inbred parental mouse strains are extensively used as animal models of human autoimmune diseases and transplantation. It is generally believed that with regard to immunologic studies, hybrid F1 mice behave in a consistent manner, equivalent to any other inbred mouse strain. In this study, we report that in comparison to inbred parental strains, individual hybrid F1 mice revealed a broad heterogeneity of proliferative response to the immunodominant determinants within hen eggwhite lysozyme (HEL). Of five parental strains tested, individual mice of three strains responding to only a few dominant HEL determinants (B6, BALB/c, and B10.PL) showed quite homogeneous patterns of response, whereas two mouse strains responsive to several determinants of HEL revealed either relative homogeneity (CBA/J mice) or heterogeneity (SJL mice) of response. However, in SJL mice, responses to major, dominant determinants of HEL were quite consistent. On the contrary, regardless of the consistency of response of parental strains, all three of F1 mice [[B6 x BALB/c]F1, [B6 x CBA/J]F1, and [SJL x B10.PL]F1] revealed significantly greater heterogeneity of response, which even involved the major, dominant determinants of HEL. We attribute the above heterogeneity of response to the competitive as well as aleatory nature of the interaction between various factors, including the coexistence of different MHC (parental as well as hybrid MHC) molecules, determinant capture, and the T cell repertoire. These results have important implications for studies on autoimmunity, infection, and vaccine design in human populations, where heterozygosity is the norm rather than the exception.     

Improved Flux Pinning in Melt-Textured YBa2Cu3O7 − δ and ErBa2Cu3O7 − δ Through Chemical Additions

The effects of Ce-based additions (CeO₂ and BaCeO₃) in combination with MgO additions on the magnetic properties of melt-textured YBa₂Cu₃O_{7 ? δ} and ErBa₂Cu₃O_{7 ? δ} have been investigated. The additions lead to improvements in the magnetic properties of both RE-123 compounds compared to samples with either addition alone or with no additions. The Ce–Mg addition combination produces a “peak effect” in the magnetic hysteresis loop without significant T _c degradation. This is postulated to be due to the formation of a new type of pinning center. Both Ce and Mg ions are thought to substitute in the RE-Ba₂Cu₃O_{7 ? δ} lattice, creating defects that produce a “peak effect” in the magnetic hysteresis loop. Mg additions alone lead to a reduced T _c, while Ce additions restore the T _c and enhance the magnitude of the peak.     

Zero-error network coding for acyclic networks

Consider transmitting a set of information sources through a communication network that consists of a number of nodes. Between certain pair of nodes, there exist communication channels on which information can be transmitted. At a node, one or more information sources may be generated, and each of them is multicast to a set of destination nodes on the network. In this paper, we study the problem of under what conditions a set of mutually independent information sources can be faithfully transmitted through a communication network, for which the connectivity among the nodes and the multicast requirements of the source information are arbitrary except that the connectivity does not form directed cycles. We obtain inner and outer bounds on the zero-error admissible coding rate region in term of the regions /spl Gamma//sub N//sup */ and /spl Gamma/~/sub N//sup */, which are fundamental regions in the entropy space defined by Yeung. The results in this paper can be regarded as zero-error network coding theorems for acyclic communication networks.     

Self-construal moderates age differences in social network characteristics.

In this study, the authors examined age differences in social network characteristics (SNC) among Hong Kong Chinese. The sample consisted of 596 Chinese adults, ranging from 18 to 91 years old. Age was positively associated with close social partners and negatively associated with peripheral social partners. For individuals who were more likely to define the self as interconnected with others (i.e., interdependent self-construal), increasing age was associated with a greater number of close social partners. The negative association between age and the number of peripheral social partners, well-documented in the Western literature, was found only among Chinese adults with lower interdependence but not among those with higher interdependence. These findings highlight the importance of examining the underlying mechanism rather than a particular pattern of SNC across cultures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability of reduced model obtained by truncation

It is shown that, for well-damped systems, reduced models obtained by truncating high-order terms of its characteristic polynomial are stable. For oscillatory systems this may not always be the case, as is demonstrated by an example.