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In order to deepen the understanding of the role and regulation mechanisms of prokaryotic global transcription regulators in complex processes, including virulence, the associations between the affinity and binding sequences of Mycobacterium tuberculosis MtrA have been explored extensively. Analysis of MtrA 294 diversified 26 bp binding sequences revealed that the sequence similarity of fragments was not simply associated with affinity. The unique variation patterns of GC content and periodical and sequential fluctuation of affinity contribution curves were observed along the sequence in this study. Furthermore, docking analysis demonstrated that the structure of the dimer MtrA-DNA (high affinity) was generally consistent with other OmpR family members, while Arg 219 and Gly 220 of the wing domain interacted with the minor groove. The results of the binding box replacement experiment proved that box 2 was essential for binding, which implied the differential roles of the two boxes in the binding process. Furthermore, the results of the substitution of the nucleotide at the 20th and/or 21st positions indicated that the affinity was negatively associated with the value of minor groove width precisely at the 21st position. The dimerization of the unphosphorylated MtrA facilitated by a low-affinity DNA fragment was observed for the first time. However, the proportion of the dimer was associated with the affinity of substrate DNA, which further suggested that the affinity was actually one characteristic of the stability of dimers. Based on the finding of 17 inter-molecule hydrogen bonds identified in the interface of the MtrA dimer, including 8 symmetric complementary ones in the conserved α4-β5-α5 face, we propose that hydrogen bonds should be considered just as important as salt bridges and the hydrophobic patch in the dimerization. Our comprehensive study on a large number of binding fragments with quantitative affinity values provided new insight into the molecular mechanism of dimerization, binding specificity and affinity determination of MtrA and clues for solving the puzzle of how global transcription factors regulate a large quantity of target genes.

In this article a small amount (4%) of a series of polymer additives were blended with polypropylene (Exxon 3746G) and polyester (Eastman 14965) polymers and the mixtures were processed. The effect of these additives on the surface energy of the polymers was characterized by the contact angle measured on single fibers and by surface energy on nonwoven webs. The results indicate that fibers modified by silicone-containing polymer additives showed the greatest increase in hydrophylicity. Meltblown webs of PP and PET with selected additive also shared the same potential increase of hydrophilicity. [ABSTRACT FROM AUTHOR]

Side-by-side bicomponent meltblown fibre webs are produced on Reicofil® bicomponent (bico) meltblown line at TANDEC using polypropylene (PP), polyethylene (PE), polyethylene terephalate (PET), polybutylene terephthalate (PBT), polyamide (PA), polytrimethylene terephthalate (PTT), polylactide (PLA), etc. In this study, fibre splitting of the bico meltblown webs is investigated by several approaches, including hydroentanglement, hot water treatment, benzoic acid treatment, and alkali treatment. The web properties and the interfacial adhesion within the bico fibre are also discussed. [ABSTRACT FROM AUTHOR]

The nucleus reticularis pontis oralis (RPO) and nucleus reticularis pontis caudalis (RPC) are implicated in the generation of rapid eye movement sleep (REM). Work in cats has indicated that GABA in RPO plays a role in the regulation of REM. We assessed REM after local microinjections into RPO and RPC of the γ-aminobutyric acid-A (GABAA) agonist, muscimol (MUS), and the GABAA antagonist, bicuculline (BIC). Rats (90-day-old male Sprague-Dawley) were implanted with electrodes for recording electroencephalographs (EEG) and electromyographs (EMG). Guide cannulae were aimed into RPO (n = 9) and RPC (n = 8) for microinjecting MUS (200, 1,000.0 μM) and BIC (0.056, 0.333, 1.0, 1,000.0, and 10,000.0 μM). Animals received bilateral microinjections of saline, MUS, and BIC (0.2 μl microinjected at 0.1 μl/min) into each region followed by 6-h sleep recordings. In RPO, MUS (1,000.0 μM) suppressed REM and BIC (1,000.0 μM) enhanced REM. In RPC, MUS (200, 1,000.0 μM) suppressed REM, but BIC (1,000.0 μM and less) did not significantly affect REM. Higher concentrations of BIC (10,000.0 μM) injected into RPO (n = 9) and RPC (n = 4) produced wakefulness and escape behavior. The results indicate that GABA in RPO/RPC is involved in the regulation of REM and suggest site-specific differences in this regulation. [ABSTRACT FROM AUTHOR]

At present,most of the improved?protocols based on LEACH (low energy adaptive clustering hierarchy) start from the aspect of cluster head election, cluster distribution, path selection, etc., but the redundancy between the data is not considered enough. This paper proposes an improved LEACH protocol combining relative information entropy (LEACH-CIE). Combined with the relative entropy model, this paper calculates the relative entropy value of the probability distribution of the data of the two adjacent cycles of the node, and then the relative entropy value is compared with the threshold to judge the redundancy of the data. By rejecting the transmission of redundant data, the purpose of reducing network energy consumption is achieved. In the data send stage, considering the communication distance, energy consumption ratio and other factors, a multi-hop forwarding routing considering its own residual energy (MFRCRE) is proposed, which can optimize node forwarding conditions and balance the energy consumption rate of each node in the network. Experimental results show that the method in this paper can effectively reduce and balance the energy consumption of network nodes to extend the network life cycle.