Statistical thermodynamic approach to vibrational solitary waves in acetanilide

We analyze the behavior of the macroscopic thermodynamic state of polymers, centering on acetanilide. The nonlinear equations of evolution for the populations and the statistically averaged field amplitudes of CO-stretching modes are derived. The existence of excitations of the solitary wave type is evidenced. The infrared spectrum is calculated and compared with the experimental data of Careri et al. [Phys. Rev. Lett. 51, 104 (1983)], resulting in a good agreement. We also consider the situation of a nonthermally highly excited sample, predicting the occurrence of a large increase in the lifetime of the solitary wave excitation. [S0031-9007(98)05407-6].8092008201

Solitons in highly excited matter: Dissipative-thermodynamic and supersonic effects

Solitary waves - arising out of nonlinearity-induced coherence of optical and acoustical vibrational modes in dissipative open systems (polymers and bulk matter) - are described in terms of a statistical thermodynamics based on a nonequilibrium ensemble formalism. The undistorted progressive wave is coupled to the normal vibrations, and three relevant phenomena follow in sufficiently away-from-equilibrium conditions: (i) A large increase in the populations of the normal modes lowest in frequency, (ii) accompanied by a large increase of the solitary-wave lifetime, and (iii) emergence of a Cherenkov-like effect, consisting in a large emission of phonons in privileged directions, when the velocity of propagation of the soliton is larger than the group velocity of the normal vibrations. Comparison with experiments is presented, which points out to the. corroboration of the theory. [S1063-651X(98)00412-7].586B7913792

AMPLIFICATION OF COHERENT POLAR VIBRATIONS IN BIOPOLYMERS - FROHLICH CONDENSATE

We consider the nonequilibrium and dissipative evolution, and the steady state of the population of vibrational polar modes in a chain of biomolecules. These polar modes are excited through a coupling with a metabolic pumping source and are in anharmonic interaction with an elastic continuum. Groups of polar modes are coupled in this way through nonlinear terms in the kinetic equations. This nonlinearity is shown to be the source of an unexpected phenomenon characterizing complex behavior in this kind of system: after a threshold of intensity of the pumping source is achieved, polar modes with the lowest frequencies increase enormously their population in a way reminiscent of a Bose-Einstein condensation (Frohlich effect). The transient time for the steady-state condensate to follow is very short (picosecond time scale) and the condensation appears even for weak values of the anharmonic coupling strength responsible for its occurrence. Further, it seemingly requires accessible levels of metabolic pumping power in order to be produced and sustained.4854049405

In Vitro Identification of Novel Plasminogen-Binding Receptors of the Pathogen Leptospira interrogans

Background: Leptospirosis is a multisystem disease caused by pathogenic strains of the genus Leptospira. We have reported that Leptospira are able to bind plasminogen (PLG), to generate active plasmin in the presence of activator, and to degrade purified extracellular matrix fibronectin. Methodology/Principal Findings: We have now cloned, expressed and purified 14 leptospiral recombinant proteins. The proteins were confirmed to be surface exposed by immunofluorescence microscopy and were evaluated for their ability to bind plasminogen (PLG). We identified eight as PLG-binding proteins, including the major outer membrane protein LipL32, the previously published rLIC12730, rLIC10494, Lp29, Lp49, LipL40 and MPL36, and one novel leptospiral protein, rLIC12238. Bound PLG could be converted to plasmin by the addition of urokinase-type PLG activator (uPA), showing specific proteolytic activity, as assessed by its reaction with the chromogenic plasmin substrate, D-Val-Leu-Lys 4-nitroanilide dihydrochloride. The addition of the lysine analog 6-aminocaproic acid (ACA) inhibited the protein-PLG interaction, thus strongly suggesting the involvement of lysine residues in plasminogen binding. The binding of leptospiral surface proteins to PLG was specific, dose-dependent and saturable. PLG and collagen type IV competed with LipL32 protein for the same binding site, whereas separate binding sites were observed for plasma fibronectin. Conclusions/Significance: PLG-binding/activation through the proteins/receptors on the surface of Leptospira could help the bacteria to specifically overcome tissue barriers, facilitating its spread throughout the host.FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico)Fundacao Butantan, BrazilFAPESP (Brazil

The great screen anomaly—a new frontier in product discovery through functional metagenomics

Functional metagenomics, the study of the collective genome of a microbial community by expressing it in a foreign host, is an emerging field in biotechnology. Over the past years, the possibility of novel product discovery through metagenomics has developed rapidly. Thus, metagenomics has been heralded as a promising mining strategy of resources for the biotechnological and pharmaceutical industry. However, in spite of innovative work in the field of functional genomics in recent years, yields from function-based metagenomics studies still fall short of producing significant amounts of new products that are valuable for biotechnological processes. Thus, a new set of strategies is required with respect to fostering gene expression in comparison to the traditional work. These new strategies should address a major issue, that is, how to successfully express a set of unknown genes of unknown origin in a foreign host in high throughput. This article is an opinionating review of functional metagenomic screening of natural microbial communities, with a focus on the optimization of new product discovery. It first summarizes current major bottlenecks in functional metagenomics and then provides an overview of the general metagenomic assessment strategies, with a focus on the challenges that are met in the screening for, and selection of, target genes in metagenomic libraries. To identify possible screening limitations, strategies to achieve optimal gene expression are reviewed, examining the molecular events all the way from the transcription level through to the secretion of the target gene product