Genome-Wide Transcriptional Profiling of the Response of Staphylococcus aureus to Cryptotanshinone

Staphylococcus aureus (S. aureus) strains with multiple antibiotic resistances are increasingly widespread, and new agents are required for the treatment of S. aureus. Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all 21 S. aureus strains tested in this experiment. Affymetrix GeneChips were utilized to determine the global transcriptional response of S. aureus ATCC 25923 to treatment with subinhibitory concentrations of CT. Transcriptome profiling indicated that the antibacterial action of CT may be associated with its action as active oxygen radical generator; S. aureus undergoes an oxygen-limiting state upon exposure to CT

N-linked glycosylation enhances hemagglutinin stability in avian H5N6 influenza virus to promote adaptation in mammals

Clade 2.3.4.4 avian H5Ny viruses, namely H5N2, H5N6, and H5N8, have exhibited unprecedented intercontinental spread in poultry. Among them, only H5N6 viruses are frequently reported to infect mammals and cause serious human infections. In this study, the genetic and biological characteristics of surface hemagglutinin (HA) from clade 2.3.4.4 H5Ny avian influenza viruses (AIVs) were examined for adaptation in mammalian infection. Phylogenetic analysis identified an amino acid (AA) deletion at position 131 of HA as a distinctive feature of H5N6 virus isolated from human patients. This single AA deletion was found to enhance H5N6 virus replication and pathogenicity in vitro and in mammalian hosts (mice and ferrets) through HA protein acid and thermal stabilization that resulted in reduced pH threshold from pH 5.7 to 5.5 for viral-endosomal membrane fusion. Mass spectrometry and crystal structure revealed that the AA deletion in HA at position 131 introduced an N-linked glycosylation site at 129 which increases compactness between HA monomers thus stabilizes the trimeric structure. Our findings provide a molecular understanding of how HA protein stabilization promotes cross-species avian H5N6 virus infection to mammalian hosts

Liquid Crystal Droplet-Embedded Biopolymer Hydrogel Sheets For Biosensor Applications

The development of simple, portable, and low-cost biosensing platforms is of great interest in the clinical diagnosis of disease. Here, we report liquid crystal (LC) droplet-embedded chitosan (CHI) hydrogel films formed by the Ag+ ion-triggered fast gelation of the CHI/surfactant complex-stabilized LC emulsion which is cast on substrates. The small sheets cut from the LC droplet-embedded hydrogel films combine the advantages of both hydrogels and LC droplets, offering a portable and label-free sensing platform for the real-time detection of bile acids in a small amount of solution. We find that the response time and detection limit of LC droplet-embedded hydrogel sheets for bile acids depend on their chemical structures

Tailoring The Surface Of Liquid Crystal Droplets With Chitosan/Surfactant Complexes For The Selective Detection Of Bile Acids In Biological Fluids

We report an approach for tailoring the surface of 4-n-pentyl-4′-cyanobiphenyl (5CB) droplets by the adsorption of chitosan (CHI) at the 5CB/aqueous interface, followed by the penetration of sodium tetradecyl sulfate (SC14S). The CHI/SC14S complex-coated 5CB droplets can be used as optical probes for the detection of cholic acid (CA) in phosphate-buffered saline and urine without dilution. We find that the CHI coating can significantly reduce the detection limit of 5CB droplets for CA. By controlling the number of CHI/SC14S complex-coated 5CB droplets, the detection limit for CA can be changed from ∼75 μM to ∼0.5 μM, which covers the concentration range of CA in individual urine with and without intestinal diseases

Protein-Induced Configuration Transitions Of Polyelectrolyte-Modified Liquid Crystal Droplets

Liquid crystal (LC) droplets dispersed in aqueous solution have emerged as an optical probe for sensing the adsorption and interaction of biological species at the LC/aqueous interface. In this paper, we modify the surface of 4-n-pentyl-4′-cyanobiphenyl (5CB) LC droplets by the adsorption of positively charged poly(diallyldimethylammonium chloride) (PDADMAC) and poly(ethylenimine) (PEI) with different molecular weights at the 5CB/water interface. The PDADMAC and PEI-modified 5CB droplets show a radial director configuration in aqueous solution with salt concentrations above 150 mM. The adsorption of negatively charged bovine serum albumin (BSA) on the positively charged PDADMAC and PEI-modified 5CB droplets through electrostatic interaction can induce the radial-to-bipolar configuration transition of the 5CB inside the droplets. We find that the concentration of BSA required to induce the configuration transition increases linearly with the decrease of the molecular weight of PDAMAC and PEI. Our results highlight the capability of the director configuration of LC droplets as an optical probe for sensing the interaction between proteins and polyelectrolytes at the LC/aqueous interface. © 2014 American Chemical Society

Short Communication Response of NAD(P)H dehydrogenase complex to the alteration of CO 2 concentration in the cyanobacterium Synechocystis PCC6803

Summary An NADPH-specific NDH-1 sub-complex was separated by native-polyacrylamide gel electrophoresis and detected by activity staining from the whole cell extracts of Synechocystis PCC6803. Low CO 2 caused an increase in the activity of this sub-complex quickly, accompanied by an evident increase in the expression of NdhK and PSI-driven NADPH oxidation activity that can reflect the activity of NDH-1-mediated cyclic electron transport. During incubation with high CO 2 , the activities of NDH-1 sub-complex and PSI-driven NADPH oxidation as well as the protein level of NdhK slightly increased at the beginning, but decreased evidently in various degrees along with incubation time. These results suggest that CO 2 concentration in vitro as a signal can control the activity of NDH-1 complex, and NDH-1 complex may in turn function in the regulation of CO 2 uptake. Key words: CO 2 concentration -CO 2 uptake -NAD(P)H dehydrogenase -Synechocystis PCC6803 Abbreviations: CCM = CO 2 concentrating mechanism. -DCMU = 3-(3,4-dichlorophenyl)-1,1-dimethylurea. -H-cells = cells grown in high CO 2 . -L-cells = cells grown in low CO 2 . -NBT = nitroblue tetrazolium. -NDH-1 = type 1 NAD(P)H dehydrogenase. -PAGE = polyacrylamide gel electrophoresi

Lag-Burst Kinetics Of Surfactant Displacement From The Liquid Crystal/Aqueous Interface By Bile Acids

Bile acids play an important role in fat digestion by displacing surfactants from the oil-water interface through emulsification. In this paper, we study the time course of the displacement of sodium dodecyl sulfate (SDS) from the liquid crystal (LC)/aqueous interface by four unconjugated bile acids, which differ in the number and position of hydroxyl groups on their steroid backbones. The competitive adsorption of bile acids displaces the SDS from the LC/aqueous interface and consequently triggers a homeotropic-to-tilted anchoring transition of the LC at the interface, which allows the displacement kinetics to be monitored by a polarizing optical microscope. The microscopy image analysis reveals that the displacement exhibits lag-burst kinetics, where a lag phase is followed by a burst phase. We find that the number and position of the hydroxyl groups of bile acids have significant impact on the lag time and burst rate of the displacement kinetics

Design Of Β-Cd-Surfactant Complex-Coated Liquid Crystal Droplets For The Detection Of Cholic Acid Via Competitive Host-Guest Recognition

β-CD-C14TAB complex-coated 5CB droplets are designed by the adsorption of β-CD-C14TAB complexes at the 5CB/aqueous interface. We show that the 5CB droplets can be used as an optical probe for the selective detection of cholic acid in aqueous solution containing uric acid and urea via competitive host-guest recognition

Efficient Evaluation of Concrete Fracture Surface Roughness Using Fringe Projection Technology

The evaluation of concrete surface roughness is crucial in the field of civil engineering. The purpose of this study is to propose a no-contact and efficient method for the measurement of the roughness of concrete fracture surfaces based on fringe-projection technology. A simple phase-correction method using one additional strip image is presented for the phase unwrapping to improve the measurement efficiency and accuracy. The experimental results indicate that the measuring error for plane height is less than 0.1mm, and the relative accuracy for measuring a cylindrical object is about 0.1%, meeting the requirements for concrete fracture-surface measurement. On this basis, three-dimensional reconstructions were carried out on various concrete fracture surfaces to evaluate the roughness. The results reveal that the surface roughness (R) and fractal dimension (D) decrease as the concrete strength increases or the water-to-cement ratio decreases, consistent with previous studies. In addition, compared with the surface roughness, the fractal dimension is more sensitive to the change in concrete surface shape. The proposed method is effective for detecting concrete fracture-surface features

Identification of Candidate Expansin Genes Associated with Seed Weight in Pomegranate (<i>Punica granatum</i> L.)

Seed weight is an important target trait in pomegranate breeding and culture. Expansins act by loosening plant cell walls and cellulosic materials, permitting turgor-driven cell enlargement. However, the role of expansin genes (EXPs) in pomegranate seed weight remains elusive. A total of 29 PgrEXPs were identified in the ‘Dabenzi’ genome. These genes were classified into four subfamilies and 14 subgroups, including 22 PgrEXPAs, 5 PgrEXPBs, 1 PgrEXPLA, and 1 PgrEXPLB. Transcriptome analysis of PgrEXPs in different tissues (root, leaf, flower, peel, and seed testa) in ‘Dabenzi’, and the seed testa of the hard-seeded pomegranate cultivar ‘Dabenzi’ and soft-seeded cultivar ‘Tunisia’ at three development stages showed that three PgrEXPs (PgrEXPA11, PgrEXPA22, PgrEXPA6) were highly expressed throughout seed development, especially in the sarcotesta. SNP/Indel markers of these PgrEXPs were developed and used to genotype 101 pomegranate accessions. The association of polymorphic PgrEXPs with seed weight-related traits (100-seed weight, 100-kernel weight, 100-sarcotesta weight, and the percentage of 100-sarcotesta to 100-seed weight) were analyzed. PgrEXP22 was significantly associated with 100-seed weight and 100-sarcotesta weight and is a likely candidate for regulating seed weight and sarcotesta development in particular. This study provides an effective tool for the genetic improvement of seed weight in pomegranate breeding programs