Quorum sensing is a process of chemical communication that bacteria use to assess cell population density and synchronize behavior on a community-wide scale. Communication is mediated by signal molecules called autoinducers. The LuxS autoinducer synthase produces 4,5-dihydroxy-2,3-pentanedione (DPD), the precursor to a set of interconverting molecules that are generically called autoinducer-2 (...

Sufficient conditions for the solvability of two-point boundary value problems for the system xi = fi(t, x1, x2) (i = 1, 2) are given, where f1 and f2 : [a1, a2]×R → R are continuous functions. 1. Statement of the problems and formulation of the main results Consider the system of ordinary differential equations xi = fi(t, x1, x2) (i = 1, 2) (1.1) with boundary conditions λi1x1(ai) + λi2x2(ai) ...

Given a connected graph G, a family F of connected graphs is called a forbidden family if no induced subgraph of G is isomorphic to any graph in F. If this is the case, G is said to be F-free. In earlier papers the authors identi ed four distinct families of triples of subgraphs that imply traceability when they are forbidden in su ciently large graphs. In this paper the authors introduce a fth...

In crop plants, aluminum (AI) rhizotoxicity is a major problem worldwide; however, the cause of AI toxicity remains elusive. The effects of AI on the inositol 1,4,5-trisphosphate (Ins[l,4,5]P3)-mediated signal transduction pathway were investigated in wheat roots. Exogenously applied AI (50 pM) rapidly inhibited root growth (<2 hr) but did not affect general root metabolism. An lns(1,4,5)P3 tra...

In the present study, the potency and immunogenicity of the inactivated bivalent vaccine of Newcastle disease (ND) and avian influenza (AI) produced by Razi institute in Iran were compared with a similar imported vaccine administered by standard methods to specific-pathogen-free (SPF) chicken. A total of 150 twenty-one-day-old SPF chickens were used for evaluating Razi and imported inactivated ...

The cross-species bacterial communication signal autoinducer 2 (AI-2), produced by the purified enzymes Pfs (nucleosidase) and LuxS (terminal synthase) from S-adenosylhomocysteine, directly increased Escherichia coli biofilm mass 30-fold. Continuous-flow cells coupled with confocal microscopy corroborated these results by showing the addition of AI-2 significantly increased both biofilm mass an...