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Effects of high-pressure processing (HPP) pretreatment and inoculation with or without Lactobacillus senmaizukei (LS) on γ-aminobutyric acid (GABA) free amino acid content, glutamic acid (Glu) decarboxylase (GAD) activity, microflora, and physicochemical properties of the cocoa beans were investigated during fermentation, and microstructural changes of cocoa beans were observed through scanning electron microscopy (SEM). Raw cocoa beans had a GABA content of 21.12 mg/100 g, which increased to 31.26 mg/100 g after spontaneous (SPO) fermentation, while in HPP-LS fermented cocoa beans can be significantly increased to 66.35 mg/100 g, due to higher GAD activity by ≥ threefold, which can improve the conversion efficiency of Glu to GABA. Therefore, the Glu content of HPP-LS cocoa beans dropped from 72.6 to 26.1 mg/100 g at the end of the fermentation. Microbiological analysis showed that HPP treatment altered the natural microbiomes of cocoa beans and reduced the counts of yeast and lactic acid bacteria. During the first 24 h of fermentation, yeast remained the dominant species in the presence/absence of LS inoculation. After 48 h, Lactobacillus spp. replaced yeast as the dominant species and acetic acid bacteria reached their maximum count after 120 h. After 72 h, the fermentation index of the HPP–LS cocoa beans was 1.02, whereas that of the SPO fermentation group reached 1.02 after 96 h; thus, HPP pre-treatment and LS inoculation reduced the fermentation time. HPP was shown to disrupt the microstructure of cocoa beans in SEM, increasing the probability of contact between GAD and Glu and upregulating GABA production. These findings can be used to evaluate the feasibility of producing GABA-enriched cocoa beans for functionality chocolate product development.Graphical Abstract: Effects of high-pressure processing (HPP) pretreatment and inoculation with or without Lactobacillus senmaizukei (LS) on γ-aminobutyric acid (GABA) free amino acid content, glutamic acid (Glu) decarboxylase (GAD) activity, microflora, and physicochemical properties of the cocoa beans were investigated during fermentation, and microstructural changes of cocoa beans were observed through scanning electron microscopy (SEM). Raw cocoa beans had a GABA content of 21.12 mg/100 g, which increased to 31.26 mg/100 g after spontaneous (SPO) fermentation, while in HPP-LS fermented cocoa beans can be significantly increased to 66.35 mg/100 g, due to higher GAD activity by ≥ threefold, which can improve the conversion efficiency of Glu to GABA. Therefore, the Glu content of HPP-LS cocoa beans dropped from 72.6 to 26.1 mg/100 g at the end of the fermentation. Microbiological analysis showed that HPP treatment altered the natural microbiomes of cocoa beans and reduced the counts of yeast and lactic acid bacteria. During the first 24 h of fermentation, yeast remained the dominant species in the presence/absence of LS inoculation. After 48 h, Lactobacillus spp. replaced yeast as the dominant species and acetic acid bacteria reached their maximum count after 120 h. After 72 h, the fermentation index of the HPP–LS cocoa beans was 1.02, whereas that of the SPO fermentation group reached 1.02 after 96 h; thus, HPP pre-treatment and LS inoculation reduced the fermentation time. HPP was shown to disrupt the microstructure of cocoa beans in SEM, increasing the probability of contact between GAD and Glu and upregulating GABA production. These findings can be used to evaluate the feasibility of producing GABA-enriched cocoa beans for functionality chocolate product development. [ABSTRACT FROM AUTHOR]

A correction to the article "DNA Topoisomerase II Is Involved in Regulation of Cyst Wall Protein Genes and Differentiation in Giardia lamblia" in the previous issue is presented.

The protozoan Giardia lamblia differentiates into infectious cysts within the human intestinal tract for disease transmission. Expression of the cyst wall protein (cwp) genes increases with similar kinetics during encystation. However, little is known how their gene regulation shares common mechanisms. DNA topoisomerases maintain normal topology of genomic DNA. They are necessary for cell proliferation and tissue development as they are involved in transcription, DNA replication, and chromosome condensation. A putative topoisomerase II (topo II) gene has been identified in the G. lamblia genome. We asked whether Topo II could regulate Giardia encystation. We found that Topo II was present in cell nuclei and its gene was up-regulated during encystation. Topo II has typical ATPase and DNA cleavage activity of type II topoisomerases. Mutation analysis revealed that the catalytic important Tyr residue and cleavage domain are important for Topo II function. We used etoposide-mediated topoisomerase immunoprecipitation assays to confirm the binding of Topo II to the cwp promoters in vivo. Interestingly, Topo II overexpression increased the levels of cwp gene expression and cyst formation. Microarray analysis identified up-regulation of cwp and specific vsp genes by Topo II. We also found that the type II topoisomerase inhibitor etoposide has growth inhibition effect on Giardia. Addition of etoposide significantly decreased the levels of cwp gene expression and cyst formation. Our results suggest that Topo II has been functionally conserved during evolution and that Topo II plays important roles in induction of the cwp genes, which is key to Giardia differentiation into cysts. Author Summary: Giardia lamblia becomes infective by differentiation into water-resistant cysts. During encystation, cyst wall proteins (CWPs) are highly synthesized and are targeted to the cyst wall. However, little is known about the regulation mechanisms of these genes. DNA topoisomerases can resolve the topological problems and are needed for a variety of key cellular functions, including cell proliferation, cell differentiation and organ development in higher eukaryotes. We found that giardial Topo II was highly expressed during encystation. Topo II is present in Giardia nuclei and is associated with the encystation-induced cwp gene promoters. Topo II has typical DNA cleavage activity of type II topoisomerases. Interestingly, overexpression of Topo II can induce cwp gene expression and cyst formation. Addition of a type II topoisomerase inhibitor, etoposide, significantly decreased the levels of cwp gene expression and cyst formation. Etoposide also has growth inhibition effect on Giardia. Our results suggest that Topo II plays an important role in induction of encystation by up-regulation of the cwp gene expression. Our results provide insights into the function of Topo II in parasite differentiation into cysts and help develop ways to interrupt the parasite life cycle. [ABSTRACT FROM AUTHOR]

The protozoan Giardia lamblia differentiates into infectious cysts within the human intestinal tract for disease transmission. Expression of the cyst wall protein (cwp) genes increases with similar kinetics during encystation. However, little is known how their gene regulation shares common mechanisms. DNA topoisomerases maintain normal topology of genomic DNA. They are necessary for cell proliferation and tissue development as they are involved in transcription, DNA replication, and chromosome condensation. A putative topoisomerase II (topo II) gene has been identified in the G. lamblia genome. We asked whether Topo II could regulate Giardia encystation. We found that Topo II was present in cell nuclei and its gene was up-regulated during encystation. Topo II has typical ATPase and DNA cleavage activity of type II topoisomerases. Mutation analysis revealed that the catalytic important Tyr residue and cleavage domain are important for Topo II function. We used etoposide-mediated topoisomerase immunoprecipitation assays to confirm the binding of Topo II to the cwp promoters in vivo. Interestingly, Topo II overexpression increased the levels of cwp gene expression and cyst formation. Microarray analysis identified up-regulation of cwp and specific vsp genes by Topo II. We also found that the type II topoisomerase inhibitor etoposide has growth inhibition effect on Giardia. Addition of etoposide significantly decreased the levels of cwp gene expression and cyst formation. Our results suggest that Topo II has been functionally conserved during evolution and that Topo II plays important roles in induction of the cwp genes, which is key to Giardia differentiation into cysts. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the moderating impacts of consumers’ self-regulatory focus on evaluations of a brand when an endorser’s image is incongruent with the characteristics of his or her recommendation messages, which is termed “source–content incongruity.” Data were obtained from an experiment design consisting of 156 participants whose self-regulatory foci were manipulated before evaluating a brand, and their attitude toward the brand based on the endorser and his or her messages. Compared with an information source–content congruity (incongruity), promotion-focused (prevention-focused) persons who confronted an incongruity (congruity) had more favorable attitudes toward the brand. Consumers under a specific regulatory focus may have different preference for a brand depending on whether a congruity exists between the recommendation sources and the message contents. The study provides evidence that consumers with a promotion focus (prevention focus) have more favorable attitude toward the brand when an information source–content incongruity (congruity) exists. In general, people naturally connect an endorser’s (information source’s) image to his or her recommendation (information content) of a product. This study first investigates the persuasiveness of external information by simultaneously taking information sources/contents and their possible incongruity into consideration. In addition, this study recognizes the influence of consumers’ self-regulatory focus (promotion versus prevention) on their perceptions of congruity between the characteristics of recommendation sources and the message contents, which are distinguished as affect-based and cognition-based. [ABSTRACT FROM AUTHOR]

In this paper, nanostructured TiO2films on a glass slide were synthesized through a simple evaporation−deposition route using volatile TiCl4as the titania precursors. TiO2nanostructures such as nanorod, nanofiber, ribbon, and network films on etched or bare glass slides were prepared by simply adjusting the heating condition of TiCl4in an autoclave. The research found that the heating temperature, heating time, and humidity in an autoclave are the major factors that affect the formation of various TiO2nanostructures. [ABSTRACT FROM AUTHOR]

In this work, the synthesis of Eu-doped titania nanotubes was studied via a two-stephydrothermal treatment method. The first hydrothermal treatment was to obtain Eu-dopedTiO2 nanopowders with good dispersity. The second treatment was to produce the correspondingnanotubes. X-ray diffraction confirmed that the nanotubes were made of hydrated titania.Scanning electron microscope and transmission electron microscope analyses showed thatthe multilayered nanotubes had an outer diameter of 12nm and inner diameter of4nm, with length up to a few microns. The Eu-doped nanotubes exhibited strongemission lines associated with the transition of Eu3+. The nanotubes prepared by the two-step hydrothermal treatment exhibited betterphotoluminescence properties than the corresponding nanopowders and nanotubesprepared directly by the one-step hydrothermal treatment. The effect of the heat treatmentof nanotubes was also studied. [ABSTRACT FROM AUTHOR]

Crossflow instability (CFI) is crucial for triggering boundary-layer flow transition over a transonic natural laminar flow (NLF) wing, whose leading edge is swept for reducing wave drag. This paper proposes a new flow parameter called the nondimensionalized crossflow pressure gradient (CFPG) to combine the effects of both wing sweep and pressure distribution on crossflow, which enables an alternative interpretation of the mechanism for CFI suppression. At first, a self-contained derivation of nondimensional form of CFPG is presented, and the Falkner-Skan-Cooke boundary layers are employed to theoretically show that the nondimensionalized CFPG does relate to wing sweep and pressure gradients. Besides, infinite obliquely placed NLF wings with different sweep angles or pressure distributions are used to numerically validate our hypothesis. Second, examples of nontapered finite-span wings are used to demonstrate the advantage of using nondimensionalized CFPG. Finally, nondimensionalized CFPG is applied to analyze the crossflow on tapered NLF forward-swept wing (FSW) and backward-swept wing (BSW) configured with the same airfoil, and the underlying flow mechanism is exposed from a new perspective. It is observed by this paper that nondimensionalized CFPG can take into account the effects of both wing sweep and pressure distribution, which leads to a different perspective to analyze the crossflow on FSW as well as BSW. [ABSTRACT FROM AUTHOR]

The mechanism by which respiratory syncytial virus (RSV) suppresses T-cell proliferation to itself and other antigens is poorly understood. We used monocyte-derived dendritic cells (MDDC) and CD4 T cells and measured [³H]thymidine incorporation to determine the factors responsible for RSV-induced T-cell suppression. These two cell types were sufficient for RSV-induced suppression of T-cell proliferation in response to cytomegalovirus or Staphylococcus enterotoxin B. Suppressive activity was transferable with supernatants from RSV-infected MDDC and was not due to transfer of live virus or RSV F (fusion) protein. Supernatants from RSV-infected MDDC, but not MDDC exposed to UV-killed RSV or mock conditions, contained alpha interferon (IFN-α; median, 43 pg/ml) and IFN-λ (approximately 1 to 20 ng/ml). Neutralization of IFN-α with monoclonal antibody (MAb) against one of its receptor chains, IFNAR2, or of IFN-λ with MAb against either of its receptor chains, IFN-λR1 (interleukin 28R [IL-28R]) or IL-10R2, had a modest effect. In contrast, blocking the two receptors together markedly reduced or completely blocked the RSV-induced suppression of CD4 T-cell proliferation. Defining the mechanism of RSV-induced suppression may guide vaccine design and provide insight into previously uncharacterized human T-cell responses and activities of interferons. [ABSTRACT FROM AUTHOR]

Prehypertension is related to a higher risk of cardiovascular events than normotension. Our previous study reported that cold exposure elevates the amplitude of the morning blood pressure surge (MBPS) and is associated with a sympathetic increase during the final sleep transition, which might be critical for sleep-related cardiovascular events in normotensives. However, few studies have explored the effects of cold exposure on autonomic function during sleep transitions and changes of autonomic function among prehypertensives. Therefore, we conducted an experiment for testing the effects of cold exposure on changes of autonomic function during sleep and the MBPS among young prehypertensives are more exaggerate than among young normotensives. The study groups consisted of 12 normotensive and 12 prehypertensive male adults with mean ages of 23.67 ± 0.70 and 25.25 ± 0.76 years, respectively. The subjects underwent cold (16°C) and warm (23°C) conditions randomly. The room temperature was maintained at either 23°C or 16°C by central air conditioning and recorded by a heat-sensitive sensor placed on the forehead and extended into the air. BP was measured every 30 minutes by using an autonomic BP monitor. Electroencephalograms, electrooculograms, electromyograms, electrocardiograms, and near body temperature were recorded by miniature polysomnography. Under cold exposure, a significantly higher amplitude of MBPS than under the warm condition among normotensives; however, this change was more exaggerated in prehypertensives. Furthermore, there was a significant decrease in parasympathetic-related RR and HF during the final sleep transition and a higher early-morning surge in BP and in LF% among prehypertensives, but no such change was found in normotensives. Our study supports that cold exposure might increase the risk of sleep-related cardiovascular events in prehypertensives. [ABSTRACT FROM AUTHOR]

Abstract: One of the critical issues in test blanket module (TBM) system is to reduce tritium permeation from Pb–Li into the water/helium coolant. Use of alumina coating is one of the most promising methods to solve this problem. In the present study, well-adhered alumina coatings on ferritic steel substrates were prepared by the sol–gel method. X-ray diffraction (XRD) and field-emission scanning electron microscope (FSEM) were employed to identify the phase and examine the microstructure of the coating. The coating prepared at 500°C is amorphous, while that prepared at 650°C is γ-Al2O3. When calcination temperature is elevated to 1100°C, α-Al2O3 is formed. The surface of the well-adhered coating was smooth and uniform. No spallations and cracks were observed in the coating or at the scale/alloy interface. The grain size of the coating remains very small even at 1100°C (in the range 30–40nm for 1100°C). The thickness of the coating can be controlled by changing aging time and the number of dipping cycles. The flexibility to coat complex geometries by this method, even inside tubes, is guaranteed. [ABSTRACT FROM AUTHOR]

This experiment adopted mixed acid (H2SO4:HNO3 = 3:1) to purify multi-walled carbon nanotubes, and used a silane coupling agent n-octyltriethoxysilane (OTES) to modify carbon nanotubes, respectively. Then we mixed OTES-modified carbon nanotubes (CNTs) with high-density polyethylene (HDPE) resin to make a composite. TGA analysis results revealed that as the CNTs'content increased, the Td10 tended to rise. The amount of composite residual at 500°C also increased, as well as the composite electrical conductivity. When a concentration of 5% OTES was used to modify the CNT, the resultant composite exhibited better electrical conductivity. [ABSTRACT FROM AUTHOR]

Abstract: A straight capillary model is developed to estimate the mass leak rate of the cast ceramic tape seals for planar solid oxide fuel cells (SOFCs), which is further rectified with consideration of microstructure complexity including the tortuosity, cross-section variation and cross-link of leak paths. The size distribution of the leak path, effective porosity and the microstructure complexity are the main factors that influence the leak rate of the cast tape seals. According to the model, Al2O3 powders are selected for preparation of the seals by tape casting, and the leak rate is evaluated under various compressive stresses and gauge pressures. The results indicate that Al2O3 powder with D 50 value about 2μm and specific surface area near 5m2 g−1 can be used for the cast tape seals; and the obtained leak rate can satisfy the allowable leak limit. [Copyright &y& Elsevier]

Wild-type human respiratory syncytial virus (HRSV) is a poor inducer of alpha/beta interferons (IFN-α/β). However, recombinant HRSV lacking the NSI and NS2 genes (ΔNS½) induced high levels of IFN-α and -β in human pulmonary epithelial cells (A549) as well as in macrophages derived from primary human peripheral blood monocytes. Results with NSI and NS2 single- and double-gene-deletion viruses indicated that the two proteins function independently as well as coordinately to achieve the full inhibitory effect, with NS1 having a greater independent role. The relative contributions of the individual NS proteins were the converse of that recently described for bovine RSV (J. F. Valarcher, J. Furze, S. Wyld, R. Cook, K. K. Conzelmann, and G. Taylor, J. Virol. 77:8426–8439, 2003). This pattern of inhibition by HRSV NS1 and NS2 also extended to the newly described antiviral cytokines IFN-λ1, -2 and -3. [ABSTRACT FROM AUTHOR]

Silicone catheter has been widely used in peritoneal dialysis. The research missions of improving blood compatibility and the ability of resisting bacterial adhesion of silicone catheter have been implemented for the biomedical requirements. However, most of modification methods of surface modification were only able to develop the blood-contacting biomaterials with good hemocompatibility. It is difficult for the biomaterials to resist bacterial adhesion. Here, agarose was selected to resist bacterial adhesion, and heparin was chosen to improve hemocompatibility of materials. Both of them were loaded into mesoporous silica nanoparticles (MSNs), which were successfully modified on the silicone film surface via electrostatic interaction. Structures of the mesoporous coatings were characterized in detail by dynamic light scattering, transmission electron microscopy, Brunauer-Emmett-Teller surface area, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscope, and water contact angle. Platelet adhesion and aggregation, whole blood contact test, hemolysis and related morphology test of red blood cells, in vitro clotting time tests, and bacterial adhesion assay were performed to evaluate the anticoagulant effect and the ability of resisting bacterial adhesion of the modified silicone films. Results indicated that silicone films modified by MSNs had a good anticoagulant effect and could resist bacterial adhesion. The modified silicone films have potential as blood-contacting biomaterials that were attributed to their biomedical properties. [ABSTRACT FROM AUTHOR]

In this study, a three dimensional model is constructed to investigate the flow distributions and the pressure variations for a 40-cell solid oxide fuel cell (SOFC) stack. Computational fluid dynamics (CFD) is used to optimize the design parameters of external manifold in the stack. The model consists of equations for the network with chamber structure of manifold. Simulation results indicate that the flow uniformity strongly depends on geometric shapes of manifold, including the joined position between tube and manifold, the dimension of manifold and the number of tubes. The ratio of flow velocity which describes the uniformity of flow distribution can be decreased by optimizing the geometrical structure of manifolds. In addition, it is found that the flow distribution can be intensively influenced by the gas resistance of the stack, which is closely related to the configuration of interconnect channels. The results summarize the importance of structure design of external manifold for stack performance. The numerical results are in good agreement with the experimental measurement in a 40-cell stack. [ABSTRACT FROM AUTHOR]

Abstract: Flash vacuum pyrolyses and photolyses of 2-methylthio-N-(arenylidene)anilines 2a–h are new and convenient methods for the syntheses of 2-arylbenzothiazoles 1a–h. [Copyright &y& Elsevier]

[Display omitted] • HHP promoting the conversion process in the myrosinase–glucosinolate system. • SEM showed that HPP induces cellular damage to radish. • HHP modify physiochemical characteristics, and decrease microbial risk. • HHP has the potential for application in the vegetable pickle processing. The myrosinase-glucosinolate system, physicochemical properties, and bacterial community were profiled during fermentation of high hydrostatic pressure (HHP) pretreated brine-pickled radishes; traditionally brine-pickled radishes were utilised as the control. Scanning electron microscopy (SEM) analysis revealed that 300 MPa pretreatment promoted brine infiltration in radish cells and damaged cellular microstructures, which activated the myrosinase-glucosinolate system. The conversion of glucosinolate (GLs) to isothiocyanates (ITC) increased and significantly enhanced the raphasatin and sulforaphene contents of pickled radish. However, 600 MPa pretreatment suppressed myrosinase activity. HHP pretreatment altered the natural radish bacterial communities by reducing the total bacterial and lactic acid bacteria counts. Lactobacillus spp. became the dominant bacterial genus within 15 d of fermentation. However, the destruction of cellular structures by HHP pretreatment also significantly decreased hardness and caused the dissolution of amino acids and TTA into brine. This caused reduced amino acid and TTA contents compared to the control group, as well as decreases in pH. HHP pretreatment suppressed the growth of spoilage bacteria (e.g. Pseudomonas , Staphylococcus , and Shewanella genera). This study provides new insight into the potential applications of HHP treatment in pickling, as it demonstrates that HHP can increase the ITC conversion rate of pickled radish, modify its physiochemical characteristics, and decrease microbial risk. Therefore, HHP is a promising preprocessing technique to be used for pickle manufacturing industry. [ABSTRACT FROM AUTHOR]

In order to improve the performance of SUS 430 alloy as a metallic interconnect material for intermediate-temperature solid oxide fuel cell (IT-SOFC), a low-cost and Cr-free spinel coating of MnCu0.5Co1.5O4 on SUS430 alloy substrate by sol-gel method is studied. MnCu0.5Co1.5O4 coated SUS430 alloy is evaluated in the simulated reducing (anode) and oxidizing (cathode) SOFC working environments at 750 °C for 1000 h about the microstructure, oxidation resistance and electrical conductivity. The result confirms that the spinel coating shows electrical conductivity of 105.5 S cm−1 at 750 °C in air and an average CET value of 12.27 × 10−6 K−1 at temperature range of 20-1000 °C. The coating layer is identified as MnCu0.5Co1.5O4 in cathode, and MnO, Cu and Co in anode atmosphere. And the thickness of the oxidized scale is around 7-8 μm after 1000 h of oxidation in both situations. The dense coating layer is effective in blocking the Cr migration/transport and depressing the growth of Cr2O3 and formation of MnCr2O4. In cathode atmosphere, the oxidation kinetics obeys the parabolic law with a rate constant as low as 1.77 × 10−15 g² cm−4 s−1 and the ASR contributed by the oxide scale is 0.3 mΩ cm². In anode atmosphere, the Δm/A of MnCu0.5Co1.5O4 coated SUS430 alloy is 0.2 mg cm−2 for 1000 h. Generally, the overall performance of the MnCu0.5Co1.5O4 coated SUS430 alloy is superior to those of bare SUS430 and other ferritic candidate alloys. [ABSTRACT FROM AUTHOR]

The aqueous solution of poly(l-Ala-co-l-Phe)-poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol)-poly(l-Ala-co-l-Phe) block copolymers (PAF-PLX-PAF) in a concentration range of 6.0−10.0 wt % underwent sol-to-gel transition as the temperature increased from 10 to 50 °C. Circular dichroism spectra, hydrophobic dye solubilization, dynamic light scattering, and transmission electron microscopy image of the polymer suggest that the polymers form micelles in water, where the hydrophilic (PLX) blocks form a shell and the hydrophobic (PAF) blocks form a core of the micelle. Circular dichroism, FTIR, and 13C NMR spectra suggest that sol-to-gel transition accompanies partial strengthening of the β-sheet structure of PAF and a decrease in molecular motion of the PLX. The sol-to-gel transition temperature could be controlled by varying the molecular weight of PAF and PLX blocks, the ratio of Ala to Phe, and the corresponding secondary structure of the polypeptide. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, novel composites for hydrogen storage were prepared by two-step re-melting and their activation characteristic and microstructure were investigated. The influence of content on the activation characteristics was analyzed by electrochemical method. With the increasing content of , activation characteristics and maximum discharge capacities of composites increase first and then decrease. The composite with 5% has the least cycle number for activation and the highest discharge capacity. It is activated after only 6 cycles at room temperature and its maximum discharge capacity reaches 274.4mAh/g. However, the composite contained 30wt% is difficult to be activated at room temperature. It is also found that it is easier to be activated for the composites at and than that at and , but their discharge capacity decay slightly at the condition of and . The XRD and SEM analysis show that, with the increasing content, the microstructure of the composites varies gradually from lamellar , acicular to massive , and the activity of the composite declines as a result of the grain size of phase grows up. [Copyright &y& Elsevier]

Giardia lamblia persists in a dormant state with a protective cyst wall for transmission. It is incompletely known how three cyst wall proteins (CWPs) are coordinately synthesized during encystation. Meiotic recombination is required for sexual reproduction in animals, fungi, and plants. It is initiated by formation of double-stranded breaks by a topoisomerase-like Spo11. It has been shown that exchange of genetic material in the fused nuclei occurs during Giardia encystation, suggesting parasexual recombination processes of this protozoan. Giardia possesses an evolutionarily conserved Spo11 with typical domains for cleavage reaction and an upregulated expression pattern during encystation. In this study, we asked whether Spo11 can activate encystation process, like other topoisomerases we previously characterized. We found that Spo11 was capable of binding to both single-stranded and double-stranded DNA in vitro and that it could also bind to the cwp promoters in vivo as accessed in chromatin immunoprecipitation assays. Spo11 interacted with WRKY and MYB2 (named from myeloblastosis), transcription factors that can activate cwp gene expression during encystation. Interestingly, overexpression of Spo11 resulted in increased expression of cwp1-3 and myb2 genes and cyst formation. Mutation of the Tyr residue for the active site or two conserved residues corresponding to key DNA-binding residues for Arabidopsis Spo11 reduced the levels of cwp1-3 and myb2 gene expression and cyst formation. Targeted disruption of spo11 gene with CRISPR/Cas9 system led to a significant decrease in cwp1-3 and myb2 gene expression and cyst number. Our results suggest that Spo11 acts as a positive regulator for Giardia differentiation into cyst. [ABSTRACT FROM AUTHOR]

Presents a corrected reprint of an error in an article about virology published in the June 24, issue of "The Journal of Virology."

Giardia lamblia differentiates into resistant cysts as an established model for dormancy. Myeloid leukemia factor (MLF) proteins are important regulators of cell differentiation. Giardia possesses a MLF homolog which was up-regulated during encystation and localized to unknown cytosolic vesicles named MLF vesicles (MLFVs). We used double staining for visualization of potential factors with role in protein metabolism pathway and a strategy that employed a deletion mutant, CDK2m3, to test the protein degradation pathway. We also explored whether autophagy or proteasomal degradation are regulators of Giardia encystation by treatment with MG132, rapamycin, or chloroquine. Double staining of MLF and ISCU or CWP1 revealed no overlap between their vesicles. The aberrant CDK2m3 colocalized with MLFVs and formed complexes with MLF. MG132 increased the number of CDK2m3-localized vesicles and its protein level. We further found that MLF colocalized and interacted with a FYVE protein and an ATG8-like (ATG8L) protein, which were up-regulated during encystation and their expression induced Giardia encystation. The addition of MG132, rapamycin, or chloroquine, increased their levels and the number of their vesicles, and inhibited the cyst formation. MLF and FYVE were detected in exosomes released from culture. The MLFVs are not mitosomes or encystation-specific vesicles, but are related with degradative pathway for CDK2m3. MLF, FYVE, and ATG8L play a positive role in encystation and function in protein clearance pathway, which is important for encystation and coordinated with Exosomes. MLF, FYVE, and ATG8L may be involved an encystation-induced protein metabolism during Giardia differentiation. [ABSTRACT FROM AUTHOR]

The density of states and optical properties of N, S, and (N, S)-doped anatase TiO2 are calculated based on the density functional theory. The results indicate that the doping S atoms occupy the Ti-atom sites in anatase TiO2 lattice. The mixing of O 2p, N 2p, S 3p, and Ti 3d states in the forbidden gap of (N, S)-codoped TiO2 can result in the higher visible-light photocatalytic activities than those monodoped TiO2. For comparison, (N, S)-codoped TiO2 was also synthesized by one-step hydrothermal method, and the optical absorption spectra obtained by experiments verified the reliability of our calculation. [ABSTRACT FROM AUTHOR]

The single crystal NiAl2O4 was prepared by a solid-state reaction. The change of its cation distribution with temperature was calculated by a modified thermodynamic equation by including a new parameter δ, which is a characteristic of nonconfiguration entropy. The calculated results showed that the degree of inversion for NiAl2O4 decreases with temperature, although the temperature dependence of cation distribution is very weak. This result was supported by X-ray diffraction measurement. [ABSTRACT FROM AUTHOR]

Nickel aluminate spinels were prepared by solid-state reaction. Their lattice parameters (ao) changed with preparation temperature, which was explained by cation distribution, vacancies formation, and cation entrance. When the preparation temperature increased from 1100° to 1200°C, ao decreased with temperature as the result of the uptake of Al2O3. After 1200°C, ao increased to temperature, which was attributed to some Nia+ exchange with tetrahedral sites and some vacancies occupancy by Ni2+ and A3+. [ABSTRACT FROM AUTHOR]

Treponema pallidum subsp. pallidum, the causative agent of syphilis, is an unculturable, genetically intractable bacterium. Here we report the use of the shuttle vector pKMR4PEMCS for the expression of a previously identified T. pallidum laminin-binding adhesin, Tp0751, in the nonadherent, culturable spirochete Treponema phagedenis. Heterologous expression of Tp0751 in T. phagedenis was confirmed via reverse transcriptase PCR analysis with tp0751 gene-specific primers and immunofluorescence analysis with Tp0751-specific antibodies; the latter assay verified the expression of the laminin-binding adhesin on the treponemal surface. Expression of Tp0751 within T. phagedenis was functionally confirmed via laminin attachment assays, in which heterologous Tp0751 expression conferred upon T. phagedenis the capacity to attach to laminin. Further, specific inhibition of the attachment of T. phagedenis heterologously expressing Tp0751 to laminin was achieved by using purified antibodies raised against recombinant T. pallidum Tp0751. This is the first report of heterologous expression of a gene from an unculturable treponeme in T. phagedenis. This novel methodology will significantly advance the field of syphilis research by allowing targeted investigations of T. pallidum proteins purported to play a role in pathogenesis, and specifically host cell attachment, in the nonadherent spirochete T. phagedenis. [ABSTRACT FROM AUTHOR]