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Capping TMβCD over AlTPyP has an excellent protective effect on seawater oxidation catalyzed by the supramolecular system AlTPyP@TMβCD against attack by Cl−.

The photoreduction of CO2 catalyzed by [fac-Re(dmbpy)(CO)3Cl] was precisely investigated through operando measurements of X-ray absorption fine structure spectroscopy (XAFS) and laser-flash FT-IR transient spectroscopy. In the early stage of the photoreaction, Re0-species assigned as penta-coordinated complex, [Re0(dmbpy)(CO)3], appeared and a delayed rise of ReII-species, [ReII(dmbpy)(CO)3CO2] (3) / [ReII(dmbpy)(CO)3COOH]+ (3’), were observed in XAFS measurements. The valence state of Re-center in the catalytic cycle changed as ReI → Re0 → ReII to be a clear evidence of an oxidative addition of CO2 to the Re0 center. In the laser-flash induced FT-IR measurements, a rise and decay of 3 followed by a delayed rise and decay of 3’ was observed. The second electron transfer from the carbon radical of TEA to 3’ induced the formation of [ReI(dmbpy)(CO)4]+ through [ReI(dmbpy)COOH]. The rate determining step of the catalytic cycle was revealed to be the protonation process of forming 3’ from 3.

The molecular catalyst sensitized system (MCSS) composed of a sensitizer and a molecular catalyst co-adsorbed on semiconductor should be one of the promising candidates of an artificial photosynthetic system that enables CO2 fixation with water as the electron donor. Here, monocarboxyphenyltrimesitylporphyrinatezinc(II) as the sensitizer and Re(dicarboxybipyridine)(CO)3(CH3CN) as the catalyst co-adsorbed on p-type semiconductor, NiO, were adopted for the MCSS catalyzed photoreduction of CO2 into CO. NiO was prepared by sol/gel method, and Li ions were doped to promote the hole carrier mobility with the amount of [Li]/[Ni] = 0, 3, 6, 9%, respectively. The conductivity of NiO increased linearly with the doping amount of Li ions, while the photoreduction of CO2 in the MCSS was enhanced under the 3, 6% doping of Li ions but was retarded under the higher doping amount of 9%. The apparently contradicting enhancement and the retardation were both successfully explained by the promotive effect of Li ions doping on the hole carrier mobility within NiO to enhance both the charge separation from the radical ion pair and charge recombination with the free hole carrier within NiO.

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We have previously found reversible photo-induced expansion and contraction of organic/inorganic clay hybrids, and even sliding of niobate nano-sheets at the macroscopic level of organic/inorganic niobate hybrids, induced by the molecular photo-isomerization of the polyfluoroalkylated azobenzene derivative (C3F-Azo-C6H) intercalated within the interlayer, which is viewed as an artificial muscle model unit. Based on systematic investigations of the steady state photo-isomerization and transient behavior of the reaction, we comprehended that the phenomena is caused by trapping of excess energy liberated during the isomerization, as well as the relaxation processes upon excitation of azobenzene chromophores in the interlayers of the hybrid. In this paper, quantitative estimation of transient 'heat' trapped in various microenvironments has been studied by each co-intercalation of temperature sensing dye molecules - rhodamine B (RhB) or tris(bipyridine)ruthenium(ii) chloride (Rubpy) with C3F-Azo-C6H within clay (SSA) nano-layers. The amount of dye molecules co-intercalated was kept to trace amounts that did not alter the bi-layered structure of the hybrid. The temperature of the microenvironment surrounding the probe molecules was estimated from the emission lifetime analysis. The evidently reduced emission lifetimes in C3F-Azo-C6H/SSA and C3H-Azo-C6H/SSA hybrids in the film state, indicated the elevation of temperature of the microenvironment upon excitation of the chromophores, which demonstrated our previous hypothesis rationalizing that the high reactivity of isomerization in the hybrid film state is caused by heat trapping via multi-step dissipation of the excess energy. With the hybrid of a hydrocarbon analogue (C3H-Azo-C6H), a distinct difference in temperature gradient was found to show the crucial role of the perfluoroalkyl chain of the surfactant that traps the excess energy to retard its dissipation leading to three-dimensional morphological motion.

An alternative approach of two-electron water splitting into hydrogen peroxide and hydrogen by one-photon was developed to bypass the photon-flux density bottleneck in artificial photosynthesis catalysed by molecular catalysts. Here we report how one-photon can induce the water splitting by earth abundant aluminum porphyrins and how the thermodynamics is rationalized. A simple energy correlation between the input energy of one-photon excitation of aluminum porphyrin species (E00 = 2.03 eV) and output energy from the splitting of two water molecules into hydrogen peroxide and hydrogen (3.54 eV) reveals a requirement for additional energy from the surrounding heat bath to drive the catalytic cycle. We have estimated the activation energies for both the two-electron oxidation of water and hydrogen evolution by Arrhenius analysis in the temperature range of 295–346 K. The activation energy for the two-electron oxidation of water catalysed by AlTMPyP was found to be pH dependent (pH 7.0, 50.6 kJ mol−1 to pH 12.5, 26.5 kJ mol−1), which reflects that the reaction is driven by both water and hydroxide ions as the substrates. Under the pH 12.5 conditions the thermodynamic correlation was well rationalized by comparing the total energy input with the energy stored in the reaction forming H2O2 and H2.

Metabolic reprogramming is considered a hallmark of some infectious diseases. However, in amoebiasis, a neglected tropical disease caused by protozoan parasite E. histolytica , metabolic changes in host cells have yet to be proven.

Macrophages promote early host responses to infection by releasing pro-inflammatory cytokines, and they are crucial to combat amoebiasis, a disease affecting millions of people worldwide. Macrophages elicit pro-inflammatory responses following direct cell/cell interaction of Entamoeba histolytica, inducing NLRP3 inflammasome activation with high-output IL-1β/IL-18 secretion. Here, we found that trophozoites could upregulate peroxiredoxins (Prx) expression and abundantly secrete Prxs when encountering host cells. The C-terminal of Prx was identified as the key functional domain in promoting NLRP3 inflammasome activation, and a recombinant C-terminal domain could act directly on macrophage. The Prxs derived from E. histolytica triggered toll-like receptor 4-dependent activation of NLRP3 inflammasome in a cell/cell contact-independent manner. Through genetic, immunoblotting or pharmacological inhibition methods, NLRP3 inflammasome activation was induced through caspase-1-dependent canonical pathway. Our data suggest that E. histolytica Prxs had stable and durable cell/cell contact-independent effects on macrophages following abundantly secretion during invasion, and the C-terminal of Prx was responsible for activating NLRP3 inflammasome in macrophages. This new alternative pathway may represent a potential novel therapeutic approach for amoebiasis, a global threat to millions.

Artificial photosynthesis, which splits water into H2/O2 or reduces CO2 and N2 by visible light, catalyzed by molecular catalysts (MCs) with/without being coupled with a solar cell should serve as ...

Two-electron water oxidation initiated by one-electron oxidation of aluminum porphyrins (AlTMPyP) is an alternative water oxidation to the conventional four-electron pathway and could help to avoid the bottleneck subject of photon-flux density in artificial photosynthesis. Here, a dramatic enhancement of the reactivity by bicarbonate ion in the two-electron water oxidation to form H2 O2 is reported. An addition of sodium carbonate (Na2 CO3 ) controlled both catalytic current and product selectivity of the two-electron water oxidation to enhance the activity of AlTMPyP at pH≈10-11. Controlled potential electrolysis experiments at different concentrations of Na2 CO3 (10-100 mm) showed that peroxide selectivity was improved up to approximately 73 % by the increase of [Na2 CO3 ] added to the system. The promotion of the reaction cycle was induced by an enhanced dynamic capturing of H2 O2 from the hydroperoxy complex of AlTMPyP through an attack of a bicarbonate ion. The detailed electrochemical studies and product selectivity indicated that the bicarbonate ion served as a good cofactor for producing H2 O2 from water. At stronger alkaline conditions (pH 12.5), however, a retardative effect of the addition of Na2 CO3 on the catalytic reactivity was observed.

A photo-responsive nanoscroll composed of niobate nanosheets and a polyfluoroalkyl azobenzene derivative (C3F-Azo-C6H) is one of the most interesting layered materials because the reversible winding and unwinding motion could be efficiently induced by photo-irradiations. Previously, we have studied a double-walled nanoscroll (DWNS) of niobate that could be synthesized by the intercalation of a cationic polyfluorinated surfactant only into the interlayer I of the layered niobate among the two interlayers, I and II. In this study, we have successfully synthesized another novel photo-responsive single-walled nanoscroll (SWNS) of niobate by a stepwise guest–guest ion-exchange method. All niobate nanosheets that were exfoliated at both interlayers I and II were efficiently converted to nanoscrolls by the intercalation of C3F-Azo-C6H. The synthetic yield has been quantitatively estimated. Though the photo-isomerization reaction of C3F-Azo-C6H was induced in the SWNS, its photo-reactivity was the lowest when compared with those of the nanosheet-stacked film and the DWNS. The photo-reactivity of C3F-Azo-C6H decreased in the order of DWNS > nanosheet-stacked film > SWNS. The different flexibility of the layered miroenvironment might influence the photo-reactivity of C3F-Azo-C6H in the niobate hybrid. The SWNS exhibited a reversible expansion and shrinkage of its interlayer spaces upon photo-irradiation, while the winding and unwinding motion was not observed, contrary to the DWNS. The direction of the expansion and shrinkage of the interlayer of the SWNS was opposite to those of the nanosheet-stacked film and the DWNS. Based on the experimental results, the tilt angle of C3F-Azo-C6H against the nanosheet surface and the matching structures of the top and bottom surfaces of the nanosheet could be the probable key factors that control the photo-reactivity of C3F-Azo-C6H in the layered microenvironment; the morphological changes of the nano hybrids was also discussed.

Myiasis refers to the infestation of living humans and vertebrate animals by dipterous larvae. Many organs can be infested by fly larvae, but cutaneous and wound myiases are the most frequently encountered clinical forms. Persistent ulcer or non-healing wound is one of the symptoms of squamous cell carcinoma which is the second most common skin cancer in the world. Here we report a case of an elderly man with a severe wound myiasis in a squamous cell carcinoma lesion of the scalp. The maggots were confirmed to be

Entamoeba nuttalli infection is highly prevalent in captive and wild macaques. A recent study suggested that the genetic factor of host macaques was correlated with the genotypes of E. nuttalli isolates. This study focused on the correlation between the rhesus macaque host major histocompatibility complex gene and E. nuttalli infection. Thirty-nine stool samples were obtained from Mount Qing-ling (Guizhou Province, China). Polymerase chain reaction analysis detected the infection rate of E. nuttalli, Entamoeba coli, and Entamoeba chattoni as 69.23%, 69.23%, and 87.18%, respectively. A new Serine-rich Protein genotype was detected, and the rRNA of E. nuttalli isolates from Mount Qian-ling was completely identical to the GY4 strain. In the distance-based neighbor-joining tree, Mamu-DRB1, not Mamu-DPB or Mamu-B gene, was related to E. nuttalli infection. Mamu-DRB1 genes of rhesus macaques in Mounts Qian-ling and Long-hu were highly polymorphic, and the rhesus macaques with two major types of Mamu-DRB1 showed susceptibility to E. nuttalli infection. The Mamu-DRB1 gene analysis in this study indicated that the Mamu-DRB1 gene is an important factor that influences the susceptibility of E. nuttalli infection in Chinese Macaca mulatta. This study contributes to a better understanding of host susceptibility to Entamoeba.

Autophagy, an evolutionarily conserved mechanism to remove redundant or dangerous cellular components, plays an important role in innate immunity and defense against pathogens, which, in turn, can regulate autophagy to establish infection within a host. However, for Entamoeba histolytica, an intestinal protozoan parasite causing human amoebic colitis, the interaction with the host cell autophagy mechanism has not been investigated. In this study, we found that E. histolytica peroxiredoxin (Prx), an antioxidant enzyme critical for parasite survival during the invasion of host tissues, could activate autophagy in macrophages. The formation of autophagosomes in macrophages treated with recombinant Prx of E. histolytica for 24 h was revealed by immunofluorescence and immunoblotting in RAW264.7 cells and in mice. Prx was cytotoxic for RAW264.7 macrophages after 48-h treatment, which was partly attributed to autophagy-dependent cell death. RNA interference experiments revealed that Prx induced autophagy mostly through the toll-like receptor 4 (TLR4)–TIR domain-containing adaptor-inducing interferon (TRIF) pathway. The C-terminal part of Prx comprising 100 amino acids was the key functional domain to activate autophagy. These results indicated that Prx of E. histolytica could induce autophagy and cytotoxic effects in macrophages, revealing a new pathogenic mechanism activated by E. histolytica in host cells.

The molecular catalyst sensitized system (MCSS), where an excited molecular catalyst adsorbed on a semiconductor such as TiO2 injects electrons to the conduction band of the semiconductor leading t...

Ticks have a cosmopolitan distribution and, as such, are also found in Japan. Ticks are typically ectoparasites of wild animals, however, humans can also be bitten when visiting environments inhabited by ticks. Herein, we describe two cases with atypical tick bites. Case 1 was an elderly Japanese male patient who presented with a fully engorged tick measuring 20 × 17 × 8 mm; it is rare for ticks to attain a length of 20 mm. Case 2 was an elderly Japanese female with severe dementia who presented with multiple tick bites, which is rare, after going missing for 6 days before being found in a densely wooded area. Ticks are responsible for the transmission of many infectious agents, such as bacteria, viruses and parasites. The National Institute of Infectious Diseases and the Ministry of Health, Labour and Welfare regularly inform citizens of the risks posed by tick bites. However, the tick bites could not be prevented in our patients. Further edification about tick bites, tick-borne diseases, and their prevention are considered necessary in Japan.

Recent development on alternative route to bypass the bottle-neck of water oxidation, two-electron oxidation of water catalyzed by earth-abundant metalloporphyrins to form hydrogen peroxide, has been briefly reviewed. The three pioneering reports by Fujishima (Honda-Fujishima effect), Meyer (chemical oxidation of water), and Lehn (photochemical reduction of CO2) triggered the extensive studies on artificial photosynthesis to have been forming the modern history of artificial photosynthesis. The current situation, especially for artificial photosynthesis by molecular catalysts, however, has faced with bottleneck subject of photon-flux-density problem of sun light radiation. In this review article, three milestones in the modern history of artificial photosynthesis, photon-flux-density problem as the bottleneck subject in water oxidation, crucial viewpoint of renewable energy factor (REF) in designing artificial photosynthesis even in fundamental stage of studies are explained. Several approaches to minimize the energy cost in REF for molecular catalysts such as utilization of earth-abundant elements and synthesis of molecular catalyst in water at ambient temperature were also introduced. Recent development of two-electron oxidation of water to form hydrogen peroxide, which would uncover the blind point of the bottleneck subject, would induce a game change in the methodologies of artificial photosynthesis.

Water soluble tin(IV)-porphyrins, trans-dihydroxy-5,10,15,20-tetra(N-methyl-4′-pyridiniumyl)porphyrinate tin (IV) (Sn(IV)TMPyP(OH)2) was successfully synthesized in high yield (90%) through one-pot process in water at room temperature by treating the parent free base (H2TMPyP) with Sn(II)Cl2. Re-investigation by the detailed kinetic analysis of the time dependent 1H NMR signals indicated that the tin(IV)-insertion reaction reversibly proceeded through three steps to start from free base dimer, [H2TMPyP]2, through Sn(II)TMPyP. New intermediate, an association complex between SnCl2 and H2TMPyP, which should be a precursor of Sn(II)TMPyP, was clearly observed in UV–vis and 1H NMR for the first time. Sn(II)TMPyP was also detected at around 500 nm in UV–vis spectroscopy, while it was silent against 1H NMR, which was supported by DFT calculation to indicate that Sn(II)TMPyP has a paramagnetic nature through substantial population on triplet spin states. To explore possible one-pot process for other porphyrins, such as neutral tetra-meso-substituted-tolylporphyrin (TTP), tetra-meso-substituted-mesitylporphyrin (TMP), and anionic tetra-meso-substituted-carboxyphenylporphyrin (TCPP), the reactions in water, binary-phase system of water/dichloromethane, and methanol were examined. The anionic TCPP suffered the tin(IV)-insertion at ambient temperature only in methanol with good yield (90%).

BACKGROUND Thrombospondin-related anonymous protein (TRAP) is a prime candidate for a malaria vaccine. Antibodies to Plasmodium vivax TRAP (PvTRAP) occur upon natural infection while specific antigenic domains remain to be addressed. METHODS The PvTRAP sequences were determined from 73 P. vivax isolates from Tak and Ubon Ratchathani provinces collected in 2013. The recombinant proteins representing four variants each for domain II (A domain) and domain IV (thrombospondin repeat region) of PvTRAP circulating in these areas were used as antigens in enzyme-linked immunosorbent assay against 246 serum samples from P. vivax-infected patients in both provinces collected during 2013 and 2014. RESULTS The prevalence of total IgG antibodies to at least one variant antigen of domain II and domain IV was 63.8% and 71.5%, respectively. Differential IgG antibody responses to these variant antigens of each domain were observed. Total IgG antibody responses to the variant antigens of each domain upon pairwise comparisons were highly correlated, suggesting immunological cross-reactivity in the majority of serum samples. A smaller proportion of serum samples contained non-cross-reactive antibodies to variants of each domain; particularly domain II in which amino acid differences significantly influenced antibody recognition. Previous malaria exposure positively affected antibody responses to domain IV. Positive seroconversion and rising antibody titres occurred within a few weeks after resolution of infections. CONCLUSIONS Both domains II and IV are targets of naturally acquired IgG antibodies. Despite sequence variation in these domains, most antibody responses were cross-reactive. A cross-sectional evaluation of antibodies to PvTRAP during acute infection could underestimate the seroprevalence.

A series of four Tin(IV)porphyrins with different substituents on meso-phenyl groups, trans-dihydroxy-5,10,15,20-tetra(p-tolyl)porphyrinatetin(IV) (Sn(IV)TTP(OH)2), trans-dihydroxy-tetra(2,4,6-trimethyl)phenylporphyrinatetin(IV) (Sn(IV)TMP(OH)2), trans-dihydroxy-5,10,15,20-tetra(p-carboxyphenyl)porphyrinatetin(IV) (Sn(IV)TCPP), and trans-dihydroxy-5,10,15,20-tetra(N-methyl-4′-pyridiniumyl)porphyrinatetin(IV) (Sn(IV)TMPyP(OH)2) have been prepared and characterized focusing on their protolytic behavior of the axial ligands, hydroxy groups, both in the ground and excites states as well as their electrochemical oxidation behavior. The two axially ligating hydroxy groups on each Tin(IV)-porphyrins exhibit protonations and deprotpnations in five steps. The pKa value of each protolytic equilibrium in the ground states was spectrophotometrically determined, while fluorescence decay time profiles indicate that the protolytic processes are sufficiently slower than the intrinsic fluorescence decay rates to lead to non-protolysis in the excited states. The oxidation peak potentials were determined by cyclic voltammetric analysis. Pourbaix diagram of each protolytic species of Sn(IV)TMPyP in water indicated that the one-electron oxidation of fully deprotonated Sn(IV)TMPyP(O−)2 is not a proton-coupled process, while the doubly hydroxy coordinated species Sn(IV)TMPyP(OH)2 has a proton-coupled one. Tin(IV)-porphyrins exhibit efficient catalytic currents on the first oxidation wave in their cyclic voltammetry and the saturated catalytic currents were high enough in a wide range of pH to be promising as water oxidation catalysts. This is the first detailed study on Tin(IV)-porphyrins to examine water oxidation ability of the one-electron oxidized form against twenty kinds of species (five protolytic species for each of the four Tin(IV)-porphyrins).

We report here a new class of co-catalysts for hydrogen evolution on TiO2 particles upon photo-irradiation. TiO2 particles prepared by sol/gel method was allowed to graft metal ion by a simple treatment with metal salts (Pt (IV), Rh (III), Cu (II), Fe(III), Al (III) ions) in water. The metal ion surface-grafted particles of TiO2(sol/gel) exhibit excellent photochemical hydrogen evolution compared to Pt (0) cluster loaded particles of TiO2(sol/gel) under the UV light irradiation of λ > 290 nm. XPS analysis shows that the valence states of the metal ions grafted on the TiO2 particles are the same with the parent metal ion salts and no metal (0) clusters were detected. DFT calculation of the simple model of metal ion/TiO2 indicated that an injected electron mostly localized on the metal ion sites, but not on Ti sites, which rationalizes the metal ion serve as the hydrogen evolution sites. Earth abundant metal ions, Cu (II), Fe (III), and Al (III) thus can provide new class of hydrogen evolution sites for artificial photosynthetic systems. To explore the possibility of utilizing semiconductor as an electron relay in the future system of molecular-catalyst-sensitized water splitting into hydrogen and hydrogen peroxide, the stability of hydrogen peroxide on various TiO2 surfaces was examined. Hydrogen peroxide was found to be pretty stable on Rh (III), Fe (III), and Al (III) ions surface-grafted TiO2, while Pt (IV) and Cu (II) ion grafted one similarly caused decomposition of hydrogen peroxide as Pt (0) cluster loaded TiO2 (Pt(0)/TiO2).

Hot tearing of an Al-7%Si-0.35%Mg alloy T-shaped specimen was analyzed by direct observation of cracking and a finite element method (FEM) stress simulation. The semi-solid state during coo...

The second most earth abundant atom incorporated meso-tetrapyridylporphyrinatesilicon(IV) (SiTPyP) as an electrochemical catalyst was newly synthesized. The two axially ligated water molecules on SiTPyP and the four meso-substituted pyridyl nitrogens suffer eight-step protonations and deprotonations. Our detailed pKa study indicated that the two axially ligated water molecules were fully deprotonated to exist as O−–Si–O− under the condition of pH > 2. Under basic conditions, SiTPyP(O−)2 exerted the two-electron oxidation of water to form hydrogen peroxide as the primary product in aqueous acetonitrile, which was initiated through a one-electron oxidation process on the electrode with faradaic yield of 84–92%.

As one of the promising molecular catalysts for the two-electron water oxidation initiated through one-electron oxidation of the catalyst, trans-diaqua-coordinated 5, 10, 15, 20-tetra(4-pyridyl)porphyrinatealuminum (III) (AlTPyP(OH2)2) was studied on the protolytic behavior of the axial ligating water molecules and the redox properties in aqueous methanol solution. The reversible stepwise protolytic reactions of the two axially ligated water molecules, as well as four peripheral pyridyl groups at the meso-position of AlTPyP, were characterized using UV–vis absorption spectroscopy, 1H NMR, fluorescence lifetime measurements, and cyclic voltammetry. The result showed that four-step protolytic equilibrium reactions of the axial ligands proceeded under the basic pH condition and those of meso-substituted pyridyl groups did also under the acidic pH condition. All the nine species are in equilibria in the ground states as characterized with each pKa value. On the other hand, they exist as individual species in the excited states having each single exponential decay time constant. Here we will report the first detailed study on the formation of nine species from a single molecule of AlTPyP through protolytic reactions in the pH range between 0.54 and 12.3.

Entamoeba nuttalli found in macaques is phylogenetically the closest species to Entamoeba histolytica and is potentially pathogenic. In this study, the prevalence of Entamoeba infections was examined in wild rhesus macaques by examining 73 and 90 fecal samples collected from two sites, Popa Taung Kalat (PTK) and Pho Win Taung (PWT), in Myanmar. The positive rates of E. nuttalli detected using PCR were 49% and 31% in PTK and PWT, respectively, but no infections of E. histolytica and E. moshkovskii were found. Entamoeba dispar was detected in 6% of samples only from PWT. Positive rates of E. chattoni and E. coli were both 70% in PWT and 67% and 79% in PTK, respectively. Six E. nuttalli strains from PTK and eight from PWT were obtained in the culture with xenic medium and then, one and two strains, respectively, were axenized and finally cloned. The genotypic analysis of serine-rich protein genes revealed two genotypes each in both sites. The genotypes found in five of six strains from PTK were similar to those from the strains found in Nepal, whereas the remaining one from PTK and two from PWT were similar to those obtained from macaques in China. The sequence of the 18S rDNA of strains with these four genotypes was identical to that of the strains from China. Six loci of tRNA-linked short tandem repeats were analyzed for further genotyping of the strains. Although there were two types in locus A-L in PTK isolates, one of each type for PTK and PWT was found in the other loci, including locus A-L in PWT strains. These results demonstrated that the E. nuttalli strains from Myanmar are closer to the strains from macaques in China rather than those from macaques in Nepal.

The reaction mechanism of photochemical water oxidation catalyzed by Al(III)-porphyrins (AlTMPyP(OH)2) covalently adsorbed through one axial OH group coordination on the surface of TiO2 particle was investigated by time resolved nanosecond laser flash photolysis (NLFP). Three types of transient species with completely different absorption and decay characteristics were detected by means of NFLP、demonstrating that the photochemical production of H2O2 from water is initiated only by one-photon excitation of catalyst followed by stepwise two-electron conversion processes, providing a promising model for photochemical water oxidation. Upon laser flash excitation of AlTMPyP adsorbed on transparent TiO2 film leads to the formation of AlTMPyP(OH) radical cation through one-electron injection from the excited singlet state of catalyst to the conduction band of TiO2. The radical cation is subsequently deprotonated into AlTMPyP(O*), which further reacts with OH-/H2O to form a key intermediate, the radical anion of AlTMPyP(O-OH), having characteristic O-O bond at the axial position within a delay time of 2-3 µs. Thereafter the radical anion efficiently transfers second electron to TiO2 leading to the formation of AlTMPyP(O-OH) (~ 67 µs), which reacts further with OH-/H2O to liberate free hydrogen peroxide as an end-product with regeneration of the starting catalyst, AlTMPyP(OH), (~ 550 µs).

Acanthamoeba spp. can be parasitic in certain situations and are responsible for serious human infections, including Acanthamoeba keratitis, granulomatous amoebic encephalitis, and cutaneous acanthamoebiasis. We analyzed the fatty acid composition of A. castellanii trophozoites and tested the inhibitory activity of the main fatty acids, oleic acid and arachidonic acid, in vitro. Oleic acid markedly inhibited the growth of A. castellanii, with trophozoite viability of 57.4% at a concentration of 200 μM. Caspase-3 staining and annexin V assays showed that apoptotic death occurred in A. castellanii trophozoites. Quantitative PCR and dot blot analysis showed increased levels of metacaspase and interleukin-1β converting enzyme, which is also an indication of apoptosis. In contrast, arachidonic acid showed negligible inhibition of growth of A. castellanii trophozoites. Stimulated expression of Atg3, Atg8 and LC3A/B genes and monodansylcadaverine labeling suggested that oleic acid induces apoptosis by triggering autophagy of trophozoites. This article is protected by copyright. All rights reserved.

We report herein a new molecular catalyst for efficient water splitting, aluminum porphyrins (tetra-methylpyridiniumylporphyrinatealuminum: AlTMPyP), containing earth's most abundant metal as the central ion. One-electron oxidation of the aluminum porphyrin initiates the two-electron oxidation of water to form hydrogen peroxide as the primary reaction product with the lowest known overpotential (97 mV). The aluminum-peroxo complex was detected by a cold-spray ionization mass-spectrometry in high-resolution MS (HRMS) mode and the structure of the intermediate species was further confirmed using laser Raman spectroscopy, indicating the hydroperoxy complex of AlTMPyP to be the key intermediate in the reaction. The two-electron oxidation of water to form hydrogen peroxide was essentially quantitative, with a Faradaic efficiency of 99 %. The catalytic reaction was found to be highly efficient, with a turnover frequency up to ∼2×104 s-1 . A reaction mechanism is proposed involving oxygen-oxygen bond formation by the attack of a hydroxide ion on the oxyl-radical-like axial ligand oxygen atom in the one-electron-oxidized form of AlTMPyP(O- )2 , followed by a second electron transfer to the electrode.

Nano-layered hybrid compounds composed of a polyfluoroalkyl azobenzene surfactant (abbreviated as C3F-Azo-C6H) and layered inorganic nanosheets undergo three-dimensional morphological changes such as reversible shrinkage and expansion of interlayer spaces, and nanosheet sliding by photo-irradiation. Previously, we have investigated the photoreactivity of C3F-Azo-C6H/clay nano-layered hybrids in various microenvironments and found a remarkable enhancement in the photoreactivity for the cis-trans photo-isomerization reaction (Φcis-trans = 1.9). In this paper, nanosecond and microsecond dynamics of trans-C3F-Azo-C6H and its assembly in various microenvironments have been studied by laser flash photolysis to get deeper insight into the extraordinary reactivity of the molecular assembly in the nano-layered microenvironment. In solution, the molecular trans-C3F-Azo-C6H exhibited only a depletion of the trans-form of azobenzene upon the laser pulse excitation. On the other hand, in the case of the C3F-Azo-C6H/clay hybrid film, the depletion of the trans-form was drastically recovered in three steps on nano- and microsecond timescales. This indicates that the once reacted C3F-Azo-C6H molecule (cis-C3F-Azo-C6H) was reverted back to the trans-form after the laser pulse. It is considered that the excess energy provided by the photo-excitation, which is immediately dissipated to the surrounding media through the intermolecular vibrational modes in solution, is trapped in the nano-layered microenvironment to thermally revert the cis-form back to the trans-form. Conversely, in the case of cis-trans isomerization of the C3F-Azo-C6H/clay hybrid film upon photo-irradiation, the reactivity would be much enhanced by the additional contribution of the thermal excess energy efficiently trapped in the nano-layered microenvironment. As compared with the hydrocarbon analogue (C3H-Azo-C6H), the subsequent recovery was very much enhanced in the C3F-Azo-C6H/clay film. The polyfluoroalkyl part of the surfactant layer plays a key role in the retarded dissipation of the excess energy by photo-excitation, which might be coupled with the three-dimensional morphological motion with efficient isomerization reactions.

Two-electron water oxidation initiated by one-electron oxidation of aluminum porphyrins (AlTMPyP) is an alternative water oxidation to the conventional four-electron pathway and could help to avoid the bottleneck subject of photon-flux density in artificial photosynthesis. Here, a dramatic enhancement of the reactivity by bicarbonate ion in the two-electron water oxidation to form H

We have recently demonstrated the potentially virulent species Entamoeba nuttalli as one of the highly prevalent parasites in rhesus macaques (Macaca mulatta) in Mount Long-hu and Gui-yang in China. Tibetan macaque (Macaca thibetana) is a unique species living in China. To evaluate the prevalence of Entamoeba species in wild Tibetan macaques, we obtained 89 stool samples in Mount E-mei of Si-chuan Province in China. PCR analysis detected E. nuttalli, Entamoeba coli, and Entamoeba polecki ST2 in 17%, 42%, and 66% of the samples, respectively, whereas Entamoeba histolytica and Entamoeba dispar were undetected. This study is the first to report on the detection of E. nuttalli from Tibetan macaques. Six E. nuttalli isolates were obtained, 18S rRNA gene and six tRNA-linked short tandem repeat (STR) loci of the isolates were sequenced. The Mantel test results gave an r value of 0.97 of relationships between geographical distance and genetic diversity of Chinese E. nuttalli populations, indicating a significant isolation-by-distance effect in Chinese E. nuttalli according to the tRNA-STR loci sequences. Structural analysis of E. nuttalli isolates based on tRNA-linked STR loci demonstrated three Chinese E. nuttalli populations with their respective features, but the Gui-yang population was located in the middle. In the distance-based NJ tree, E. nuttalli isolates were divided into five different branches, and E-mei isolates were attributed to an independent branch to distinguish them from Gui-yang and Long-hu isolates. Genetic analysis in this study provided clues of the genetic differences between E. nuttalli isolates from Tibetan macaques and rhesus macaques in China.

Photo-responsive nanoscrolls can be successfully fabricated by mixing a polyfluoroalkyl azobenzene derivative and a niobate nanosheet, which is exfoliated from potassium hexaniobate. In this study, we have found that the photo-responsive nanoscroll shows a morphological motion of winding and unwinding, which is basically due to the nanosheet sliding within the nanoscroll, by efficient photo-isomerization reactions of the intercalated azobenzene in addition to the interlayer distance change of the nanoscrolls. The relative nanosheet sliding of the nanoscroll is estimated to be ca. 280 nm from the AFM morphology analysis. The distance of the sliding motion is over 20 times that of the averaged nanosheet sliding in the azobenzene/niobate hybrid film reported previously. Photo-responsive nanoscrolls can be expected to be novel photo-activated actuators and artificial muscle model materials.

5, 10, 15, 20-tetra(N-methylpyridinium-4′-yl)porphyrinate tin(IV) (SnTMPyP) was found to exhibit two-electron water oxidation to form hydrogen peroxide as a primary product initiated by electrochemical one-electron oxidation. Dioxygen was also formed by the further two-electron oxidation of hydrogen peroxide on the anode. Isotope labelling experiment using H218O and enzyme catalase that converts H2O2 into O2 revealed an incorporation of 18O into the oxidation products, indicating the two-electron oxidation of water in the electrolysis catalysed by SnTMPyP. The overpotential of forming H2O2 under the practical condition is 370 mV. The Faradaic yield of the water oxidation was almost quantitative both under the basic (pH 10.9) and the nearly neutral conditions (pH 8.5), though the reactivity was much higher under the basic condition.

Two-electron water oxidation is an energy-efficient way for solar energy conversion and one of the promising candidates to get through the bottleneck of artificial photosynthesis, photon- flux density problem. In light of renewable energy factor (REF) that is defined by Energy output/Energy input, for the realization of practical systems, the energy input for catalyst preparation have much importance. Herein, we report a facile, cost-effective and environment benign synthesis of zinc (II) 5, 10, 15, 20-tetrakis(N-methylpyridinium-4′-yl)porphyrin (ZnTMPyP) in water at room temperature. We observed coordination of water molecules to the central Zn(II) ion of ZnTMPyP and four-step protolytic equilibria among five axially ligated species. Electrochemical and controlled potential electrolysis experiments, as well as theoretical DFT calculation, showed that ZnTMPyP(OH)(O−) exhibits the two-electron water oxidation to form hydrogen peroxide as the primary product initiated by one-electron oxidation process of the catalyst with a moderate turnover frequency (96.4 s-1) and a small overpotential (∼60 mV). Isotope-labeled studies clearly showed that water molecule served as an oxygen atom source in the formation of hydrogen peroxide.

Entamoeba nuttalli found in non-human primates is the phylogenetically closest species to Entamoeba histolytica and is potentially pathogenic. However, infection of wild long-tailed macaques (Macaca fascicularis) with E. nuttalli has not been found. In this study, the prevalence of Entamoeba infections in wild long-tailed macaques was examined in seven locations in six provinces of Thailand. The positive rate for E. nuttalli in 214 fecal samples was 43.9% using PCR, but no infection with E. histolytica or Entamoeba dispar was found, demonstrating that long-tailed macaque is one of the natural hosts for E. nuttalli. Twenty-four E. nuttalli isolates were successfully cultured and four of them were axenized. The sequences of the 18S ribosomal RNA genes of E. nuttalli from long-tailed macaques differed from those of E. nuttalli isolates from other species of wild macaques. Eleven types of sequences in serine-rich protein genes were identified in the 24 isolates and these were specific for each location in Thailand. By analysis of six tRNA-linked short tandem repeat loci, these isolates were divided into 14 types, and each type was also location-specific. Phylogenetic analysis revealed correlation between genotypes of the parasite and the geographic distribution of the host macaques. Genetic distance and geographic distance correlated significantly in a Mantel test, with r values of 0.888 based on the tRNA-linked short tandem repeat loci and 0.815 based on the serine-rich protein genes. These results suggest that genetic divergence and co-evolution of the parasite occurred during dispersion and colonization of the host macaque, and that genotypic analysis of the parasite may enable identification of the geographic localization of the host.

Thrombospondin-related adhesive protein (TRAP) of malaria parasites is essential for sporozoite motility and invasions into mosquito's salivary gland and vertebrate's hepatocyte; thereby, it is a promising target for pre-erythrocytic vaccine. TRAP of Plasmodium vivax (PvTRAP) exhibits sequence heterogeneity among isolates, an issue relevant to vaccine development. To gain insights into variation in the complete PvTRAP sequences of parasites in Thailand, 114 vivax malaria patients were recruited in 2006-2007 from 4 major endemic provinces bordering Myanmar (Tak in the northwest, n = 30 and Prachuap Khirikhan in the southwest, n = 25), Cambodia (Chanthaburi in the east, n = 29) and Malaysia (Yala and Narathiwat in the south, n = 30). In total, 26 amino acid substitutions were detected and 9 of which were novel, resulting in 44 distinct haplotypes. Haplotype and nucleotide diversities were lowest in southern P. vivax population while higher levels of diversities were observed in other populations. Evidences of positive selection on PvTRAP were demonstrated in domains II and IV and purifying selection in domains I, II and VI. Genetic differentiation was significant between each population except that between populations bordering Myanmar where transmigration was common. Regression analysis of pairwise linearized Fst and geographic distance suggests that P. vivax populations in Thailand have been isolated by distance. Sequence diversity of PvTRAP seems to be temporally stable over one decade in Tak province based on comparison of isolates collected in 1996 (n = 36) and 2006-2007. Besides natural selection, evidences of intragenic recombination have been supported in this study that could maintain and further generate diversity in this locus. It remains to be investigated whether amino acid substitutions in PvTRAP could influence host immune responses although several predicted variant T cell epitopes drastically altered the epitope scores. Knowledge on geographic diversity in PvTRAP constitutes an important basis for vaccine design provided that vaccination largely confers variant-specific immunity.

In mitochondria, compatibility of proteins encoded in mitochondrial DNA and nuclear DNA is essential for the normal functioning of the organelle. Incompatibility between mitochondrial and nuclear DNA can lead to dysfunctional respiration, mitochondrial diseases, and lethal problems, which suggests that the presence of heterologous mitochondria is unfavorable. In a previous study, we established a transplant method for DNA-lacking mitochondria (mitosomes) in the anaerobic protozoan Entamoeba histolytica. In this study, interspecies transplant of mitosomes from E. histolytica into Entamoeba invadens, which is a parasitic protozoon of reptiles, was performed using the microinjection method at various temperatures and injection volumes. When E. invadens was used as recipient, it showed higher tolerance to a lower temperature and larger injection volume, in comparison with E. histolytica. After microinjection, donor mitosomes expressing HA-tag conjugated protein were observed in recipient cells by immunofluorescent staining. The heterologous mitosomes-injected cells proliferated and growth rate of the microinjected-cells was similar to that of intact cells. Therefore, we conclude that interspecies transplant of DNA-lacking mitochondria does not result in incompatibility.

Entamoeba nuttalli infection is prevalent in captive and wild macaques. Recent studies have suggested that genotypes of E. nuttalli isolates are correlated with the geographical distribution of host macaques. Correlation of amoebic genotypes with genetic diversity of host macaques was analyzed in present study. Sixty fresh stool samples were obtained from wild Tibetan macaques living in Mount Huang (HS) of the An-hui Province in China. PCR analysis revealed that the most prevalent Entamoeba species was E. chattoni (E. polecki ST2) (86.7%) followed by E. nuttalli (58.3%) and E. coli (25%). Six E. nuttalli HS isolates were successfully cultured. The tRNA-linked short tandem repeat (STR) loci and serine-rich protein gene of E. nuttalli isolates from four different regions of China (Mount Long-hu, Gui-yang, Mount E-mei, and HS, the former three isolates were obtained in previous studies) were studied and high numbers of polymorphisms were detected. When genetic diversity of different populations of E. nuttalli isolates was compared with geographical distance, an r

In Nepal, gastrointestinal infections due to parasites including Entamoeba species are common. The main aim of this study was to identify species of Entamoeba using genotypic analysis. The prevalence of Entamoeba infections was examined by PCR in fecal samples from 143 inhabitants living close to wild rhesus macaques in Kathmandu, Nepal. The numbers of positive cases were one (0.7%) for E. histolytica, eight (5.6%) for E. dispar, seven (4.9%) for E. coli, and two (1.4%) for E. chattoni (E. polecki ST2). No infections with E. nuttalli, E. moshkovskii, and E. polecki ST1 were found. In E. dispar, at least seven different genotypes were detected from the eight samples by sequence analysis of tRNA-linked short tandem repeats. Different genotypes were found even in a couple from the same family. This is the first report demonstrating that E. dispar with high genotypic diversity is prevalent, rather than E. histolytica, in Kathmandu, and that zoonotic transmission of E. chattoni from rhesus macaques might occur in the inhabitants.

Aluminium(III)-tetramesitylporphyrin, with the Earth’s the most abundant metal and the third most abundant element as the Al(III) ion, induces the photochemical oxygenation of cyclohexene in deaerated aqueous acetonitrile to form the corresponding epoxide and alcohol with water as both electron and oxygen atom donor upon visible light irradiation. The Al(III) should be the most available and meaningful element to be utilized in the artificial photosynthetic unit. The excited triplet state of the water-coordinated porphyrin is responsible for the photochemical oxygenation.

Visible-light-induced two-electron oxidation of water to form hydrogen peroxide (H2O2) was investigated in a photovoltaic cell (PVC) composed of an ITO electrode coated by tetrakis-(4-carboxylphenyl) porphyrinatogermanium(IV) (1)-adsorbed titanium oxide (TiO2) particles as an anode (1/TiO2/ITO) and a Pt electrode as a cathode in an aqueous solution containing an electrolyte. The short-circuit photocurrent was observed under irradiation of the 1/TiO2/ITO anode with the light of 550 nm under aerated conditions. Simultaneously, H2O2 was detected only in the anode chamber. After irradiation for 6 h, the turnover number (TON) and the faradaic efficiency for the formation of H2O2 were estimated to be 9.0 and 92%, respectively. The action spectrum for the formation of H2O2 was well consistent with the absorption spectrum of 1. These findings indicate that H2O2 is produced by the excitation of 1 on the anode through a quantitative process with the obtained faradaic current. It was concluded that water acted as an electron donor on the anode, while molecular oxygen acted as an electron acceptor under aerated conditions, and several different types of ions also acted as an electron acceptor under argon atmosphere on the cathode. It is suggested that the photooxidation of water to form H2O2 was initiated by a photoinduced electron transfer from the excited singlet state of 1 to TiO2 to generate the porphyrin radical cation (1+ ), which underwent a proton dissociation from the hydroxo axial ligand to give a Ge-oxyl complex as a key intermediate for a two-electron activation of water to form hydrogen peroxide.

Silicon as the second most abundant element on Earth was effectively utilized as the central atom in the porphyrin to induce photochemical oxygenation of alkenes as the first example of photocatalytic reaction through activation of water molecule in the presence of K2PtCl6 as an electron acceptor. Oxygen atom of water was confirmed to be incorporated in the oxygenated product by the photoreaction with H218O. The excited triplet state of silicon porphyrin was revealed to be responsible for the photochemical oxygenation. The one-electron oxidized silicon porphyrin was predicted by DFT calculation to have its spin population mostly on the axially ligated hydroxyl oxygen atom. The oxyl radical character of the axial ligand could rationalize the oxygenation reaction.

Free-living amoebae of the genus Acanthamoeba are widespread protozoans that can cause serious infectious diseases. This study characterised phosphoglycerate dehydrogenase (PGDH) and phosphoserine aminotransferase (PSAT) in the phosphorylated serine biosynthetic pathway of Acanthamoeba castellanii. The PGDH gene encodes a protein of 442 amino acids with a calculated molecular weight of 47.7 kDa and an isoelectric point (pI) of 7.64. Meanwhile, the PSAT gene encodes a protein of 394 amino acids with a calculated molecular weight of 43.8 kDa and a pI of 5.80. Confocal microscopy suggests that PGDH is mainly diffused in the cytoplasm, whereas PSAT is located in the inner part of the cell membrane. The messenger RNA (mRNA) expression levels of PGDH and PSAT vary depending on growth state under consecutive culture conditions. No significant changes in the mRNA expression levels of both PGDH and PSAT occur after the incubation of L-serine with Acanthamoeba. This result indicates that exogenous serine exerts no influence on the expression of these genes and that the so-called feedback inhibition of both PGDH and PSAT in Acanthamoeba differs from that in bacteria or other organisms. We propose that the enzymes in the phosphorylated serine biosynthetic pathway function in amoeba growth and proliferation.

A new water-soluble silicon(IV)-tetra(4-carboxyphenyl)porphyrin (SiTCPP) with silicon(iv), the second most abundant element on Earth, in the center of porphyrin was synthesized. Fundamental properties including protolytic behaviour of axially coordinating hydroxy groups, and electrochemical behaviour were characterized. The properties were compared with those of silicon(IV)-tetra(2,4,6-trimethylphenyl)porphyrin (SiTMP) and silicon(IV)-tetra(4-trifluoromethylphenyl)porphyrin (SiTFMPP) and discussed in respect to the electron donating/withdrawing effect of the substituents. Two axially coordinating hydroxy groups of SiTCPP exhibit a four-step protolytic behaviour under the acidic conditions along with a single step protolysis of peripheral carboxyl groups. Though SiTCPP and SiTFMPP did not show any reactivity in the photochemical oxygenation of a substrate with K2PtCl6 as a sacrificial electron acceptor, the first oxidation wave in the electrochemical process of SiTCPP and SiTFMPP showed catalytic behaviour in aqueous acetonitrile solution at any pH condition, in contrast to SiTMP which has only a reversible oxidation wave under neutral and weakly acidic conditions. The criteria for the electrochemical oxidative activation of water and the photooxygenation of the substrate were obtained. The higher oxidation wave of Si-porphyrins than ∼0.86 volt vs. SHE is required for the electrochemical oxidation of water, while suitable protecting groups such as a methyl substituent is a requisite for the photochemical oxygenation with K2PtCl6 as a sacrificial electron acceptor.

Novel environment-benign one-pot syntheses of water-soluble porphyrins, trans-dihydroxy-5,10,15,20-tetra(N-methyl-4′-pyridiniumyl)porphyrinate tin(IV) (Sn(IV)TMPyP(OH)2) and water-insoluble trans-dihydroxy-5,10,15,20-tetra(4-pyridyl)porphyrinate tin(IV) (Sn(IV)TPyP(OH)2), were found to proceed in water as solvent at room temperature with high yield (90 and 93%).

Water-soluble cationic 5,10,15,20-tetra(N-methyl-4′-pyridiniumyl)porphyrinatoaluminum(III) (AlTMPyP) has been synthesized by novel one-pot reaction between the parent free-base porphyrin and trimet...

Entamoeba histolytica is an anaerobic parasitic protist and possesses mitosomes, one of the most highly divergent mitochondrion-related organelles (MROs). Although unique metabolism and protein/metabolite transport machinery have been demonstrated in Entamoeba mitosomes, the mechanism of mitosomal fusion and fission remains to be elucidated. In this study, we demonstrate that two dynamin-related proteins (DRPs) are cooperatively involved in the fission of Entamoeba mitosomes. Expression of a dominant negative form of EhDrpA and EhDrpB, and alternatively, repression of gene expression of EhDrpA and EhDrpB genes, caused elongation of mitosomes, reflecting inhibition of mitosomal fission. Moreover, EhDrpA and EhDrpB formed an unprecedented hetero-oligomeric complex with an approximate 1:2 to 1:3 ratio, suggesting that the observed elongation of mitosomes is likely caused by the disruption and instability of the complex caused by an imbalance in the two DRPs. Altogether, this is the first report of a hetero-oligomeric DRP complex which participates in the fission of mitochondria and MROs.

Visible light-induced, two-electron reduction of carbon dioxide to carbon monoxide, catalyzed by a newly synthesized metal complex dyad composed of a zinc porphyrin as a light-harvesting sensitizer and a rhenium bipyridyl complex as a catalytic moiety for the reduction, was attained for the first time on the p-type semiconductor NiO without any sacrificial electron donor. The fluorescence of the dyad adsorbed on the NiO nanoparticles (20–30 nm diameter) was efficiently quenched with a very short lifetime (29 ps) compared with the intrinsic value of 1.6 ns in DMF. The radical anion of the zinc porphyrin was actually formed upon excitation of 5,10,15,20-tetra(4-carboxy)phenylporphyrinatozinc (ZnTCPP) (5) on NiO by fast electron injection from NiO to the excited ZnTCPP with a lifetime of ∼180 ns, corresponding to the charge recombination with the hole on NiO. An electrochemical cell composed of the dyad-adsorbed NiO particle layers on an FTO cathode and platinum as a counter electrode in CO2-saturated DMF solution showed a constant cathodic photocurrent upon visible light irradiation (λ = 420 nm) accompanied by the formation of the two-electron-reduced product (CO). The photoreduction was further enhanced by a factor of 5.5 in a system prepared by co-adsorbing ZnTCPP (5) as a light- and electron-harvesting moiety and the dyad ZnDMCPP-Re(bpy)(NHAc) (1) as a catalytic moiety on NiO, as a promising example of the design of a CO2 photoreduction system as the reduction terminal end of an artificial photosynthetic system.