Association between dietary variety status and sarcopenia as defined by the Asian Working Group for Sarcopenia 2019 consensus in older outpatients at a hospital specializing in geriatric medicine: A cross­sectional study with baseline data of prospective cohort study (JUSTICE­TOKYO study).

To the best of our knowledge, little is known about the association between dietary variety status and sarcopenia in university-affiliated geriatric hospital in elderly. The present study aimed to investigate, in a multidisciplinary setting, the prevalence of sarcopenia and association between dietary variety status and sarcopenia in older outpatients at Juntendo Tokyo Koto Geriatric Medical Center (Tokyo, Japan). Between October 2020 and December 2021, a cross-sectional study of outpatients aged ≥65 years [458 male (44%) and 584 female (56%); mean age, 78.2±6.1 years] was conducted to assess prevalence of sarcopenia, according to Asian Working Group for Sarcopenia 2019 criteria, and the relationship between dietary variety status and sarcopenia. Patient profile, comorbidities, drug use, neuropsychological data, abdominal symptoms, pulmonary function and dietary variety status were collected. Of 1,042 subjects, there were 223 (21.4%) with [142 male (63.7%) and 81 female (36.3%); mean age, 80.6±6.3 years] and 819 (78.6%) without sarcopenia [316 male (38.6%) and 503 female (61.4%); mean age, 77.6±5.8]. In multivariate analysis, older age, male sex, low body mass index, high Brinkman Index and phase angle, low quality of life, history of daycare use, diabetes mellitus, osteoporosis and low Mini-Mental State Examination and Dietary Variety Score were related to sarcopenia. The prevalence of sarcopenia was higher in than in community-dwelling individuals. Dietary variety status was associated with sarcopenia.

Xanthophyll Carotenoids Reduce the Dysfunction of Dermal Fibroblasts to Reconstruct the Dermal Matrix Damaged by Carbonylated Proteins.

Although extracellular carbonylated proteins (CPs) are found at higher levels in sun-exposed skin, their impact on the cellular functions of fibroblasts and their involvement in the progression of photoaging skin are not fully clarified. In our previous study, we reported that extracellular CPs increase levels of intracellular oxidative stress and result in the accumulation of newly synthesized CPs in normal human dermal fibroblasts (NHDF). Furthermore, fibroblasts exposed to CP-BSA, which is a model of extracellular CPs, had upregulated expression levels of mRNAs encoding matrix metalloproteinase-1 (MMP-1) and interleukin-8/CXCL8 (IL-8/CXCL8). These facts suggested the possibility that extracellular CPs induce a fragile structure in the dermis through the degradation of collagen and elastin. The purpose of this study was to characterize the efficacy of natural carotenoids, such as astaxanthin analogs, produced by Hematococus pluvialis (CHPs) to improve the impaired functions of fibroblasts exposed to CPs. CHPs suppressed the intracellular CP levels elevated by CP-BSA, restored mRNA expression levels of factors involved in the formation and assembly of collagen and elastin fibers and improved the formation of those fibers impaired by CP-BSA. We conclude that CHPs function as antiaging substances due to their restoration of the impaired formation of collagen and elastin fibers caused by extracellular soluble CPs.

An Extract of Young Olive Fruit Residues Attenuates Oxidative Stress in HaCaT Keratinocytes through the Ativation of Nrf2 Signaling.

Residues of olive fruit (ROF) after the extraction of oils are an increasing source of industrial waste, because olive oil is becoming more popular as a healthy food. It has been reported that olives have some polyphenols that have an antioxidation capability. On the other hand, excess oxidative stress disrupts epidermal barrier function. This study was conducted to determine whether ROF could be utilized as an antioxidant source to reduce industrial wastes and to identify possible active materials to maintain healthy skin. Olive fruits are categorized into two groups depending on the time of harvest, young fruit (YF) and mature fruit (MF). Thus, we examined the antioxidant potentials of extracts from YF and from MF to remove reactive oxygen species (ROS) from biological and chemical aspects. HaCaT keratinocytes cultured with extracts of YF or MF had reduced levels of intracellular ROS in spite of the relatively low chemical capability against ROS scavenging. The biological effects of the YF extract were superior to those of the MF extract. The YF extract showed effective reductions of intracellular ROS and carbonylated proteins that were elevated by the stress-related hormone cortisol. In addition, the YF extract reinforced the intracellular antioxidation capability through the activation of Nrf2 signaling. Taken together, the YF extract was an effective source to reinforce the intracellular antioxidation capability. We conclude from these results that utilizing ROF would lead to the reduction of industrial wastes and would supply active materials to maintain healthy skin.

Protective Effects of Sacran, a Natural Polysaccharide, Against Adverse Effects on the Skin Induced by Tobacco Smoke.

Recent increases in air pollution have raised concerns about its adverse effects on human health. Sacran is a natural polysaccharide isolated from a cyanobacterium. We previously reported that sacran improves skin conditions because of its effects as an artificial barrier against external stimuli, which suggested that sacran might protect the skin against air pollutants. The goal of this study was to characterize the potential of sacran to protect human skin against damage from air pollutants and to compare sacran with hyaluronic acid (HA). Sacran that was topically applied on the skin stayed on the surface or in the stratum corneum. Sacran-treated filters had a shielding effect against benzo[a]pyrene (BaP) and aldehyde compounds contained in tobacco smoke. Sacran suppressed the upregulation of cytochrome P4501A1 messenger ribonucleic acid (mRNA), which is a xenobiotic-metabolizing enzyme induced by BaP, and other responses against tobacco smoke in HaCaT keratinocytes. Furthermore, topical application of a serum containing 0.04% sacran on the skin reduced levels of carbonylated proteins in corneocytes of tobacco smokers. Sacran showed superior effects in every characteristic measured, compared with HA. We conclude that sacran ameliorates the oxidative stress initiated by tobacco smoke by shielding the skin surface and protects human skin.

Pyridoxine (VB6 ) restores the down-regulation of serine palmitoyltransferase mRNA expression in keratinocytes cultured in highly oxidative conditions through enhancement of the intracellular antioxidant system.

BACKGROUND: Pyridoxine (VB6 ), which acts as a coenzyme in the biosynthesis of niacin, is formulated in pharmaceuticals to treat skin roughness. However, the mechanism of action of VB6 is not known precisely. OBJECTIVE: This study was conducted to clarify the influence of highly oxidative conditions on the expression of skin moisture-related mRNAs and to evaluate the preventive effects of VB6 focusing on antioxidant behaviour. METHODS: Intracellular levels of reactive oxygen species (ROS) in normal human epidermal keratinocytes (NHEKs) were determined using the 2',7'-dichlorofluorescein diacetate assay. Real-time PCR was employed to investigate the influence of higher oxidative conditions on the expression of mRNAs encoding serine palmitoyl transferase (SPT) and filaggrin, and to characterize the mechanism of the antioxidant effect of VB6 . Intracellular glutathione was quantified using an assay based on the glutathione recycling system with 5,5'-dithiobis (2-nitrobenzoic acid) reagent and glutathione reductase. Carbonylated proteins (CPs) were semi-quantified by detecting aldehyde residues. RESULTS: Treatment of NHEKs with BSO increased the level of intracellular CPs by interfering with intracellular glutathione synthesis. Further, treatment with BSO down-regulated the expression level of SPT mRNA, but VB6 restored SPT mRNA expression in BSO-treated NHEKs. VB6 decreased the level of intracellular CPs with or without BSO treatment in a dose-dependent manner. In addition, VB6 increased levels of intracellular NADH/NADPH and glutathione through the activation of nuclear factor E2-related factor 2 (Nrf2) signalling. CONCLUSION: These results suggest that highly oxidative conditions cause an impaired skin barrier function due to the down-regulation of SPT that results in skin roughness. VB6 improved the down-regulation of SPT mRNA expression initiated by highly oxidative conditions by enhancing the intracellular antioxidant system.

The impact of carbonylated proteins on the skin and potential agents to block their effects.

Carbonylated proteins (CPs) are synthesized by reactions between amino groups in proteins and reactive aldehyde compounds (RAC) yielded from lipid peroxidation initiated by reactive oxygen species (ROS). In the skin, CPs are detected in a higher frequency at sun-exposed sites of the skin in elderly subjects. Since CPs in the stratum corneum (SC) have been reported to correlate with skin water content and transepidermal water loss, it is considered that the accumulation of CPs in the SC involves the loss of skin moisture functions. However, the roles of CPs in the dermis on skin physiology are still unclear. The purpose of this study was to investigate the roles of CPs in the dermis during the progression of photoaged skin and to propose a method to prevent or reduce the synthesis of CPs. The exposure of human normal dermal fibroblasts to CPs increased intracellular ROS levels and the synthesis of intracellular CPs. In addition, CPs caused morphological changes of fibroblasts. Furthermore, CPs caused alterations of mRNA expression levels of dermal matrix-related proteins, such as upregulating MMP-1 and IL-8. These results indicated that CPs disrupt construction of the dermal matrix. On the other hand, α-tocopherol and ß-carotene suppressed the synthesis of RAC during lipid peroxidation which resulted in the reduction of UVA-induced CPs in the SC. From these results, we propose that extracellular CPs increase intracellular ROS levels and contribute to alterations of the dermal matrix. To prevent the synthesis of CPs, the application of α-tocopherol or ß-carotene could be effective.

Correlations between skin hydration parameters and corneocyte-derived parameters to characterize skin conditions.

BACKGROUND: Skin hydration is generally assessed using the parameters of skin surface water content (SWC) and trans-epidermal water loss (TEWL). To date, few studies have characterized skin conditions using correlations between skin hydration parameters and corneocyte parameters. AIMS: The parameters SWC and TEWL allow the classification of skin conditions into four distinct Groups. The purpose of this study was to assess the characteristics of skin conditions classified by SWC and TEWL for correlations with parameters from corneocytes. METHODS: A human volunteer test was conducted that measured SWC and TEWL. As corneocyte-derived parameters, the size and thick abrasion ratios, the ratio of sulfhydryl groups and disulfide bonds (SH/SS) and CP levels were analyzed. RESULTS: Volunteers were classified by their median SWC and TEWL values into 4 Groups: Group I (high SWC/low TEWL), Group II (high SWC/high TEWL), Group III (low SWC/low TEWL), and Group IV (low SWC/high TEWL). Group IV showed a significantly smaller size of corneocytes. Groups III and IV had significantly higher thick abrasion ratios and CP levels. Group I had a significantly lower SH/SS value. The SWC/TEWL value showed a decline in order from Group I to Group IV. CONCLUSION: Groups classified by their SWC and TEWL values showed characteristic skin conditions. We propose that the SWC and TEWL ratio is a comprehensive parameter to assess skin conditions.

A red pumpkin seed extract reduces melanosome transfer to keratinocytes by activation of Nrf2 signaling.

BACKGROUND: The induction of skin pigmentation by ultraviolet (UV) radiation has been shown to result from factors secreted from UV-exposed keratinocytes that enhance melanogenesis in melanosomes (MSs) and stimulates their transfer to keratinocytes. Among those factors, it has been reported that α-melanocyte stimulating hormone, which is converted from the precursor proopiomelanocortin (POMC) following UV exposure, stimulates the transfer of MSs from melanocytes to surrounding keratinocytes. OBJECTIVE: The purpose of this study was to evaluate the effects of a red pumpkin seed (RPS) extract on the transfer of MSs to keratinocytes and to clarify the involvement of reactive oxygen species (ROS) on the UVB-induced transfer of MSs. METHODS: The transfer of MSs into keratinocytes was examined by measuring the incorporation of fluorescent beads, which were used as pseudo-MSs. mRNA expression levels of POMC, Nrf2, and Nrf2-related genes were determined using real-time PCR. Intracellular ROS levels were estimated with H2 DCFDA. RESULTS: The incorporation of fluorescent beads into keratinocytes was enhanced by treatment with the conditioned medium (CM) from keratinocytes exposed to UVB or H2 O2 . UVB or H2 O2 exposed keratinocytes had an up-regulated mRNA expression level of POMC. Treatment of keratinocytes with the RPS extract enhanced their intracellular antioxidant system via the activation of Nrf2 signaling and suppressed their incorporation of fluorescent beads that had been stimulated by the CM from UVB or H2 O2 exposed keratinocytes. CONCLUSION: These results indicate that the RPS extract suppresses MS transfer stimulated by ROS generated following UVB exposure through the activation of Nrf2 signaling.

Defensive Effects of a Unique Polysaccharide, Sacran, to Protect Keratinocytes against Extracellular Stimuli and Its Possible Mechanism of Action.

Sacran, a polysaccharide isolated from the alga Aphanothece sacrum (Suizenji-nori), has unique physical and physiological characteristics. In a previous study, we reported that sacran improves skin conditions in individuals who suffer from atopic dermatitis (AD), focusing on its trapping function against extrinsic stimuli compared with hyaluronic acid (HA). First, we examined the penetration of sacran through stratum corneum (SC) with an impaired barrier function using immature reconstructed human epidermal equivalents. Sacran penetrates the SC to living cell layers of the epidermis, which suggested that sacran would attenuate adverse influences in keratinocytes caused by extracellular factors such as irritants or proinflammatory cytokines such as interleukin 1α (IL-1α). Sacran markedly reduced the cell damage induced by a nonionic detergent, sodium lauryl sulfate (SLS). Moreover, sacran restored the elevation of intracellular reactive oxygen species (ROS) levels stimulated by SLS and by IL-1α. These effects of sacran were superior to those of HA. In order to investigate the restoration effects of sacran, the influence of sacran on the physical properties of lipid bilayers was evaluated by measuring the order parameter using the ESR spin-labeling method. Because sacran failed to cause changes in the order parameters of liposomes and HaCaT keratinocytes, these results indicate that sacran does not interact with lipid bilayers although it restored changes in the order parameter caused by SLS. The sum of these results demonstrates that sacran reduces the influence of extracellular stimuli by its trapping effects. We conclude that the improving action of sacran is based on its trapping effect.

Topical treatment with sacran, a sulfated polysaccharide from Aphanothece sacrum, improves corneocyte-derived parameters.

Sacran, a polysaccharide isolated from Aphanothece sacrum (Suizenji-nori) alga, has unique characteristics in terms of its physiological properties and effects on the skin, and has recently become a focus of attention as a novel biomaterial. In a previous study, we reported the unique physical characteristics of sacran, which forms a gel-like film containing water in the presence of polyols. This film resists penetration by water and chemicals. We expected this unique physical characteristic to act as an artificial barrier upon the application of sacran to the skin. In the present study, we tested the efficacy of sacran application in healthy individuals who reported previous symptoms of dry or inflamed skin, to evaluate the potential benefits of sacran for skin care in patients with mild atopic dermatitis. Compared with placebo, sacran-containing serum did not significantly alter either the water content of the skin surface or transepidermal water loss. However, subjects using the serum showed improvements in corneocyte parameters including size, percentage of thick abrasion, ratio of SH to SS groups, ratio of interleukin (IL)-1 receptor antagonist to IL-1α, and carbonylated protein level. These results indicate that the sulfated polysaccharide sacran is an effective agent for improving or maintaining the skin conditions.

Sodium Lauryl Sulfate Stimulates the Generation of Reactive Oxygen Species through Interactions with Cell Membranes.

Sodium lauryl sulfate (SLS), a representative anionic surfactant, is well-known to induce rough skin following single or multiple topical applications. The mechanism by which SLS induces rough skin is thought to result from the disruption of skin moisture function consisting of NMF and epidermal lipids. However, a recent study demonstrated that topically applied SLS easily penetrates into the living cell layers of the epidermis, which suggests that physiological alterations of keratinocytes might cause the SLS-induced rough skin. This study was conducted to clarify the effects of SLS on keratinocytes to demonstrate the contribution of SLS to the induction of rough skin. In addition, the potentials of other widely used anionic surfactants to induce rough skin were evaluated. HaCaT keratinocytes treated with SLS had increased levels of intracellular ROS and IL-1α secretion. Application of SLS on the surface of a reconstructed epidermal equivalent also showed the increased generation of ROS. Further, SLS-treated cells showed an increase of intracellular calpain activity associated with the increase of intracellular Ca2+ concentration. The increase of intracellular ROS was abolished by the addition of BAPTA-AM, a specific chelator of Ca2+. In addition, IL-1α also stimulated ROS generation by HaCaT keratinocytes. An ESR spin-labeling study demonstrated that SLS increased the fluidity of membranes of liposomes and cells. Together, those results indicate that SLS initially interacts with cell membranes, which results in the elevation of intracellular Ca2+ influx. Ca2+ stimulates the secretion of IL-1α due to the activation of calpain, and also increases ROS generation. IL-1α also stimulates ROS generation by HaCaT keratinocytes. We conclude from these results that the elevation of intracellular ROS levels is one of the causes of SLS-induced rough skin. Finally, among the other anionic surfactants tested, sodium lauryl phosphate has less potential to induce rough skin because of its lower generation of ROS.

Carbonylated proteins exposed to UVA and to blue light generate reactive oxygen species through a type I photosensitizing reaction.

BACKGROUND: Carbonylated proteins (CPs) are generated by the reaction of basic amino acid residues in proteins with aldehyde compounds produced during lipid peroxidation. CPs in the stratum corneum (SC) impact skin conditions such as skin moisture functions including water content and transepidermal water loss (TEWL). In addition, CPs can be frequently seen in the SC from sun-exposed sites compared with sun-protected sites. OBJECTIVE: The aim of this study was to reveal whether CPs could be a generation source of reactive oxygen species (ROS) in the SC following exposure to ultraviolet (UV) radiation and to identify the type of ROS and its generation mechanism. METHODS: ROS generation was detected using a methyl cypridina luciferin analog (MCLA) chemiluminescence system and an ESR spin-trapping method. CPs in porcine SC, in a keratin film and in bovine serum albumin (BSA) were prepared by reaction with acrolein. Levels of protein carbonylation were quantified by detecting aldehyde residues. RESULTS: CP levels in the SC were increased in a UVA energy-dependent manner. That result suggested that a source of ROS generation existed in the SC initiated and produced the carbonylation of SC proteins. Carbonylated BSA and carbonylated porcine SC sheets exhibited fluorescence spectra at an excitation wavelength of 430nm and an emission wavelength of 520nm. Irradiation of the SC with UVA increased protein carbonylation and the amount of autofluorescence in the SC. ROS generation in the SC caused by UVA and by short-wavelength visible light (blue light, 400-470nm) was detected by the MCLA chemiluminescence system. Artificially carbonylated porcine SCs and keratin films had increases of chemiluminescence intensity after exposure to both light sources as well. The addition of superoxide dismutase to the MCLA system completely abolished the incremental chemiluminescence intensity after both UVA and blue light exposure of the SC. In addition, acrolein-treated BSA gave ESR signals like hydroxyl radicals (OH) converted from superoxide anion radicals (O2-) during irradiation with a xenon arc lamp containing UVA and visible light. From the sum of these results, we consider that CPs are produced from O2- initially generated from exposure to UVA and blue light. CONCLUSION: CPs are excited by absorbing sunlight, particularly UVA and blue light, and result in the generation of O2- through a CPs progress new protein carbonylation in stratum corneum through ROS generation. photosensitizing reaction. Further, the results suggest that the O2- produces CPs in the SC through lipid peroxidation in the sebum, and finally affects skin conditions including color and moisture functions.

Anti-photoaging capability of antioxidant extract from Camellia japonica leaf.

It is well known that the Camellia japonica leaf exhibits antioxidant activity because of its high content of polyphenolic compounds. Thus, the extract prepared from mature leaves of C. japonica (CJML) has been widely used as an anti-ageing material in foods and cosmetics. Concerning the process of growing C. japonica, it is expected that the extract from green leaves (CJGL) has superior effects compared with that from mature leaves. However, there are few reports that discuss the difference between green and mature leaves. In this study, both CJML and CJGL were extracted with 50% 1,3-butylene glycol (1,3-BG) and used for investigations. In a chemical examination, we compared both extracts in terms of scavenging activities against hydrogen peroxide (H2 O2 ) and hydroxyl radicals. CJGL exhibited higher scavenging activities against both types of ROSs compared with CJML. In addition, CJGL reduced the carbonylation of tape-stripped stratum corneum (SC) after UVB irradiation. In a biological study, the intra-cellular ROS level of HaCaT keratinocytes precultured with CJGL for 24 h was significantly lower than that of the control cells. Furthermore, cell damage induced by H2 O2 exposure was attenuated by 24 h precultivation with CJGL but not by 2 h precultivation. The results of examinations indicate that CJGL possess properties that reduce oxidative stress. In addition, the result of 2 h precultivation with CJGL suggests that CJGL might affect the status of intra-cellular antioxidants.

Constructing and testing the thermodynamic limits of synthetic NAD(P)H:H2 pathways.

NAD(P)H:H(2) pathways are theoretically predicted to reach equilibrium at very low partial headspace H(2) pressure. An evaluation of the directionality of such near-equilibrium pathways in vivo, using a defined experimental system, is therefore important in order to determine its potential for application. Many anaerobic microorganisms have evolved NAD(P)H:H(2) pathways; however, they are either not genetically tractable, and/or contain multiple H(2) synthesis/consumption pathways linked with other more thermodynamically favourable substrates, such as pyruvate. We therefore constructed a synthetic ferredoxin-dependent NAD(P)H:H(2) pathway model system in Escherichia coli BL21(DE3) and experimentally evaluated the thermodynamic limitations of nucleotide pyridine-dependent H(2) synthesis under closed batch conditions. NADPH-dependent H(2) accumulation was observed with a maximum partial H(2) pressure equivalent to a biochemically effective intracellular NADPH/NADP(+) ratio of 13:1. The molar yield of the NADPH:H(2) pathway was restricted by thermodynamic limitations as it was strongly dependent on the headspace:liquid ratio of the culture vessels. When the substrate specificity was extended to NADH, only the reverse pathway directionality, H(2) consumption, was observed above a partial H(2) pressure of 40 Pa. Substitution of NADH with NADPH or other intermediates, as the main electron acceptor/donor of glucose catabolism and precursor of H(2), is more likely to be applicable for H(2) production.

Glyceraldehyde-3-phosphate ferredoxin oxidoreductase from Methanococcus maripaludis.

The genome sequence of the non-sugar-assimilating mesophile Methanococcus maripaludis contains three genes encoding enzymes: a nonphosphorylating NADP(+)-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and glyceraldehyde-3-phosphate ferredoxin oxidoreductase (GAPOR); all these enzymes are potentially capable of catalyzing glyceraldehyde-3-phosphate (G3P) metabolism. GAPOR, whose homologs have been found mainly in archaea, catalyzes the reduction of ferredoxin coupled with oxidation of G3P. GAPOR has previously been isolated and characterized only from a sugar-assimilating hyperthermophile, Pyrococcus furiosus (GAPOR(Pf)), and contains the rare metal tungsten as an irreplaceable cofactor. Active recombinant M. maripaludis GAPOR (GAPOR(Mm)) was purified from Escherichia coli grown in minimal medium containing 100 muM sodium molybdate. In contrast, GAPOR(Mm) obtained from cells grown in medium containing tungsten (W) and W and molybdenum (Mo) or in medium without added W and Mo did not display any activity. Activity and transcript analysis of putative G3P-metabolizing enzymes and corresponding genes were performed with M. maripaludis cultured under autotrophic conditions in chemically defined medium. The activity of GAPOR(Mm) was constitutive throughout the culture period and exceeded that of GAPDH at all time points. As GAPDH activity was detected in only the gluconeogenic direction and GAPN activity was completely absent, only GAPOR(Mm) catalyzes oxidation of G3P in M. maripaludis. Recombinant GAPOR(Mm) is posttranscriptionally regulated as it exhibits pronounced and irreversible substrate inhibition and is completely inhibited by 1 muM ATP. With support from flux balance analysis, it is concluded that the major physiological role of GAPOR(Mm) in M. maripaludis most likely involves only nonoptimal growth conditions.

Inorganic polyphosphate interacts with ribosomes and promotes translation fidelity in vitro and in vivo.

Inorganic polyphosphate is a biological macromolecule consisting of multiple phosphates linked by high-energy bonds. Polyphosphate occurs in cells from all domains of life, and is known to play roles in a diverse collection of cellular functions. Here we examine the relationship between polyphosphate and protein synthesis in Escherichia coli. We report that polyphosphate associates with E. coli ribosomes in vitro. Characterization of this interaction reveals that both long-chain and short-chain polyphosphates interact with the ribosome. Intact 70S ribosomes, as well as 50S and 30S subunits, display a specific interaction with polyphosphate that is mediated primarily by contacts with ribosomal proteins. Additionally, we examined functional consequences of a ppk mutation, which severely reduces levels of intracellular polyphosphate. Extracts from ppk mutants contain lower levels of polysomes than wild-type cells, suggesting a defect in mRNA utilization or the mRNA-ribosome interaction. Ribosomes from wild-type and ppk mutant cells were isolated, and their activities were compared using a polyU RNA in vitro translation assay. While rates of polyphenylalanine synthesis are similar, use of ribosomes from ppk cells results in a misincorporation rate about five times higher compared with the rate observed when ribosomes from wild-type cells are used. Mistranslation rates in vivo were measured directly, and ppk mutants displayed higher readthrough frequencies for two different stop codons. Taken together, these results indicate that polyphosphate plays an important role in maintaining optimal translation efficiency in vivo and in vitro.

Caged multiwalled carbon nanotubes as the adsorbents for affinity-based elimination of ionic dyes.

Multiwalled carbon nanotubes (MWCNTs) were used as the active elements for the first time for affinity-based elimination of ionic dyes. MWCNTs were encapsulated in cross-linked alginate (ALG) microvesicles using Ba2+ as the bridging ion. The Ba2+-alginate matrix constitutes a cage which holds the physically trapped MWCNTs. The cage carries negative charges on its surface. The cage restricts the access of anions of large molecular weight, such as humic acids, because of electrostatic repulsion. The cage also restricts the access of colloids of large size, because of size exclusion. Ionic dyes partition into the cage and then are captured by MWCNTs probably on the basis of van der Waals interactions occurring between the hexagonally arrayed carbon atoms in the graphite sheet of MWCNTs and the aromatic backbones of the dyes. As a result of these interactions the target species, namely, the ionic dyes, are eliminated efficiently by the MWCNTs of Ba2+-ALG/MWCNT composite adsorbents. The adsorptive capacities for elimination of acridine orange, ethidium bromide, eosin bluish, and orange G (the model species used for this study) were found as high as 0.44, 0.43, 0.33, and 0.31 micromol, respectively, for 1.0 mg of the caged MWCNTs. Adsorptive experiments with carbon nanofibers and activated carbons as the adsorbents were also performed. The MWCNT-based adsorbents provided the best capability for the affinity-based elimination of these targeted species. Biocompatibility experiments performed in vitro and in vivo provided promising results, suggesting potential applications of the caged MWCNTs in in situ environmental remediation.