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Transcription factor [[sigma].sup.28] in Chlamydia trachomatis ([[sigma].sup.28.sub.Ct]) plays a role in the regulation of genes that are important for late-stage morphological differentiation. In vitro mutational and genetic screening in Salmonella enterica serovar Typhimurium was performed in order to identify mutants with mutations in region 4 of [[sigma].sup.28.sub.Ct] that were defective in [[sigma].sup.28]-specific transcription. Specially, the previously undefined but important interactions between [[sigma].sup.28.sub.Ct] region 4 and the flap domain of the RNA polymerase [beta] subunit ([beta]-flap) or the -35 element of the chlamydial hctB promoter were examined. Our results indicate that amino acid residues E206, Y214, and E222 of [[sigma].sup.28.sub.Ct] contribute to an interaction with the [beta]-flap when [[sigma].sup.28.sub.Ct] associates with the core RNA polymerase. These residues function in contacts with the [beta]-flap similarly to their counterpart residues in Escherichia coli [[sigma].sup.70]. Conversely, residue Q236 of [[sigma].sup.28.sub.Ct] directly binds the chlamydial hctB -35 element. The conserved counterpart residue in E. coli [[sigma].sup.70] has not been reported to interact with the -35 element of the [[sigma].sup.70] promoter. Observed functional disparity between [[sigma].sup.28.sub.Ct] and [[sigma].sup.70] region 4 is consistent with their divergent properties in promoter recognition. This work provides new insight into understanding the molecular basis of gene regulation controlled by [[sigma].sup.28.sub.Ct] in C. trachomatis.

The [sigma] transcription factor confers the promoter recognition specificity of RNA polymerase (RNAP) in eubacteria. Chlamydia trachomatis has three known sigma factors, [[sigma].sup.66], [[sigma].sup.54], and [[sigma].sup.28]. We developed two methods to facilitate the characterization of promoter sequences recognized by C. trachomatis [[sigma].sup.28] ([[sigma].sup.28.sub.Ct]). One involved the arabinose-induced expression of plasmid-encoded [[sigma].sup.28.sub.Ct] in a strain of Escherichia coli defective in the [[sigma].sup.28] structural gene, fliA. The second was an analysis of transcription in vitro with a hybrid holoenzyme reconstituted with E. coli RNAP core and recombinant [[sigma].sup.28.sub.Ct]. These approaches were used to investigate the interactions of [[sigma].sup.28.sub.Ct] with the [[sigma].sup.28.sub.Ct]-dependent hctB promoter and selected E. coli [[sigma].sup.28] ([[sigma].sup.28.sub.Ec])-dependent promoters, in parallel, compared with the promoter recognition properties of [[sigma].sup.28.sub.EC]. Our results indicate that RNAP containing [[sigma].sup.28.sub.Ct] has at least three characteristics: (i) it is capable of recognizing some but not all [[sigma].sup.28.sub.EC]-dependent promoters; (ii) it can distinguish different promoter structures, preferentially activating promoters with upstream AT-rich sequences; and (iii) it possesses a greater flexibility than [[sigma].sup.28.sub.EC] in recognizing variants with different spacing lengths separating the -35 and -10 elements of the core promoter.

Form‐stable phase change materials (PCMs) have great potential to regulate the unbalanced heat demand and supply, yet most of the PCMs are in powder, plate, or bulk rigid forms, difficult to adhere to the heat source or target substrates. Herein, PCMs coatings based on reactive poly(ethylene glycol) (RPEG) are developed for direct thermal energy exchange and storage. RPEG with highly reactive silanol groups is obtained by reaction of PEG with 3‐isocyanatopropyltriethoxysilane (IPTS), followed by hydrolyzation in weak acid. Cross‐linked PCMs coatings are obtained on various substrates, including cotton fabric, wood, tinplate, and even irregular objects. The coatings show obvious solid‐solid phase transition properties and high energy storage densities (142.8 J g−1). Multi‐walled carbon nanotubes (MWCNTs) are further doped into the coatings aided by a self‐cross‐linkable dispersant. The composite coatings exhibit excellent high‐temperature form stability and rapid thermal exchange properties owing to the formation of the cross‐linked network between RPEG and MWCNTs. Thermal regulation clothes are prepared by a spray coating method, which show no performance deterioration after washing three times, indicating good washing durability. [ABSTRACT FROM AUTHOR]

The identification of surface-exposed components of the major outer membrane protein (MOMP) of Chlamydia is critical for modeling its three-dimensional structure, as well as for understanding the role of MOMP in the pathogenesis of Chlamydia-related diseases. MOMP contains four variable domains (VDs). In this study, VDII and VDIV of Chlamydia trachomatis serovar F were proven to be surface-located by immuno-dot blot assay using monoclonal antibodies (MAbs). Two proteases, trypsin and endoproteinase Glu-C, were applied to digest the intact elementary body of serovar F under native conditions to reveal the surface-located amino acids. The resulting peptides were separated by SDS-PAGE and probed with MAbs against these VDs. N-terminal amino acid sequencing revealed: (1) The Glu-C cleavage sites were located within VDI (at Glu61) and VDIII (at Glu225); (2) the trypsin cleavage sites were found at Lys79 in VDI and at Lys224 in VDIII. The tryptic peptides were then isolated by HPLC and analyzed with a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer and a quadrupole-orthogonal-TOF mass spectrometer coupled with a capillary liquid chromatograph. Masses and fragmentation patterns that correlated to the peptides cleaved from VDI and VDIII regions, and C-terminal peptides Ser333-Arg358 and Ser333-Lys350 were observed. This result demonstrated that these regions are surface-exposed. Data derived from comparison of nonreduced outer membrane complex proteolytic fragments with their reduced fractions revealed that Cys26, 29, 33, 116, 208, and 337 were involved in disulfide bonds, and Cys26 and 337, and 116 and 208 were paired. Based on these data, a new two-dimensional model is proposed. [ABSTRACT FROM AUTHOR]

Efficient recovery of rare scattered metal Re(VII) from various resources is a prerequisite due to its important application. Herein, a type of novel nanofibrous membrane, 0.4P(Ph-3MVIm-Br)-3PVP/2TPU, is successfully prepared by electrospinning, where poly(ionic liquid) P(Ph-3MVIm-Br) is incorporated and could supply more adsorption sites. Meanwhile, PVP (polyvinyl pyrrolidone) and TPU (thermoplastic polyurethane) ensured the water flux and the structural stability of the membrane. The nanofibrous membrane exhibited a high adsorption capacity for ReO 4 −, which can reach 128 mg g−1 at pH 5. Its water flux is as high as 433 L m−2 h−1 at 0.4 g of poly(ionic liquid) addition, membrane thickness of 20 μm, and pressure of 1 bar. Furthermore, 0.4P(Ph-3MVIm-Br)-3PVP/2TPU nanofibrous membrane can remove 91.7% of ReO 4 − within 30 min. After 9 times recycling, the adsorption efficiency of the membrane can still maintain more than 90%. Dynamic ReO 4 − removal with 0.4P(Ph-3MVIm-Br)-3PVP/2TPU after one cycle was accomplished with a breakthrough volume of 24 mL ReO 4 − solution (feed 10 mg L−1, 100 mg membrane). The exchange of ReO 4 − and Br− of poly(ionic liquid) mostly promote the adsorption of ReO 4 −. Moreover, the structure of the membrane has excellent selectivity, mechanical performance, strong acid and alkali resistance stability, which endow the membrane easy to operate in practical applications. [Display omitted] • Nanofibrous membrane can remove 91.7 % of ReO 4 − within 30 min. • It has a great adsorption capacity of 128 mg g−1 for ReO 4 − at pH 5. • It has a good selectivity for ReO 4 − in the presence of SO 4 2− or NO 3 −. • It unfolds prominent regeneration ability after nine consecutive cycles. • It can achieve a water flux of 433 L m−2 h−1. [ABSTRACT FROM AUTHOR]

Reasonable design of the structure and complementary compounding of electrode materials is helpful to enhance capacitive deionization (CDI) performance. Herein, a novel 0D-3D hierarchical electrode material containing Na 2 Ti 3 O 7 nanoparticles anchored at hollow red blood cell (HRBC)-like nitrogen-rich carbon (HRBC-NTO/N-C-60) was prepared via selective protection, pyrolysis, and alkalization. Specifically, a HRBC-like NH 2 -MIL-125-based material (HRBC-MOF-60) was first constructed by a selective protection approach of tannic acid (TN), which addresses the shortcomings of using sacrificial templates or corrosive agents. Afterwards, HRBC-NTO/N-C-60 was obtained in situ by annealing and alkalization of HRBC-MOF-60. The nitrogen-rich carbon with a HRBC-like structure has the ability to rapidly transport electrons, and its porous structure enables remarkable charge transfer. Benefiting from the grafted 3D N-doped porous carbon with a HRBC-like structure, well-dispersed 0D Na 2 Ti 3 O 7 nanoparticles, and satisfactory bonding effects, HRBC-NTO/N-C-60 exhibited high specific capacitance and fast ionic and electronic diffusion kinetics. Moreover, HRBC-NTO/N-C-60 was well-suited for desalination by functioning as a cathode material for capacitive deionization (CDI), and delivering a high desalination capacity of 66.8 mg g -1 in 200 mg L -1 NaCl solution at 1.4 V. This work introduces an excellent high-performance candidate for electrochemical deionization as well as affording afflatus for accurately inventing OD-3D hierarchical materials with hollow structures., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The identification of surface-exposed components of the major outer membrane protein (MOMP) of Chlamydia is critical for modeling its three-dimensional structure, as well as for understanding the role of MOMP in the pathogenesis of Chlamydia-related diseases. MOMP contains four variable domains (VDs). In this study, VDII and VDIV of Chlamydia trachomatis serovar F were proven to be surface-located by immuno-dot blot assay using monoclonal antibodies (MAbs). Two proteases, trypsin and endoproteinase Glu-C, were applied to digest the intact elementary body of serovar F under native conditions to reveal the surface-located amino acids. The resulting peptides were separated by SDS-PAGE and probed with MAbs against these VDs. N-terminal amino acid sequencing revealed: (1) The Glu-C cleavage sites were located within VDI (at Glu61) and VDIII (at Glu225); (2) the trypsin cleavage sites were found at Lys79 in VDI and at Lys224 in VDIII. The tryptic peptides were then isolated by HPLC and analyzed with a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer and a quadrupole-orthogonal-TOF mass spectrometer coupled with a capillary liquid chromatograph. Masses and fragmentation patterns that correlated to the peptides cleaved from VDI and VDIII regions, and C-terminal peptides Ser333-Arg358 and Ser333-Lys350 were observed. This result demonstrated that these regions are surface-exposed. Data derived from comparison of nonreduced outer membrane complex proteolytic fragments with their reduced fractions revealed that Cys26, 29, 33, 116, 208, and 337 were involved in disulfide bonds, and Cys26 and 337, and 116 and 208 were paired. Based on these data, a new two-dimensional model is proposed.