Fatty acids regulate pigmentation via proteasomal degradation of tyrosinase: a new aspect of ubiquitin-proteasome function

Fatty acids are common components of biological membranes that are known to play important roles in intracellular signaling. We report here a novel mechanism by which fatty acids regulate the degradation of tyrosinase, a critical enzyme associated with melanin biosynthesis in melanocytes and melanoma cells. Linoleic acid (unsaturated fatty acid, C18:2) accelerated the spontaneous degradation of tyrosinase, whereas palmitic acid (saturated fatty acid, C16:0) retarded the proteolysis. The linoleic acid-induced acceleration of tyrosinase degradation could be abrogated by inhibitors of proteasomes, the multicatalytic proteinase complexes that selectively degrade intracellular ubiquitinated proteins. Linoleic acid increased the ubiquitination of many cellular proteins, whereas palmitic acid decreased such ubiquitination, as compared with untreated controls, when a proteasome inhibitor was used to stabilize ubiquitinated proteins. Immunoprecipitation analysis also revealed that treatment with fatty acids modulated the ubiquitination of tyrosinase, i.e. linoleic acid increased the amount of ubiquitinated tyrosinase whereas, in contrast, palmitic acid decreased it. Furthermore, confocal immunomicroscopy showed that the colocalization of ubiquitin and tyrosinase was facilitated by linoleic acid and diminished by palmitic acid. Taken together, these data support the view that fatty acids regulate the ubiquitination of tyrosinase and are responsible for modulating the proteasomal degradation of tyrosinase. In broader terms, the function of the ubiquitin-proteasome pathway might be regulated physiologically, at least in part, by fatty acids within cellular membranes.     

Petunia guarapuavensis (Solanaceae): A new species from planalto of Paraná and Santa Catarina,Brazil

Petunia guarapuavensis, a new species fromplanalto (high plateau) of Paraná and Santa Catarina in Brazil, is described, and its morphological distinction from related species, features of the habitats, and geographical distribution are discussed.     

The effect of processing of Chlorellavulgaris: K-5 on in vitro and in vivo digestibility in rats

Two experiments were done to clarify whether or not cell rupture is necessary to improve the digestibility of major components of Chlorella vulgaris: K-5. Chlorella was treated with or without high pressure homogenization (1 × 10⁸ N/m² at less than −20°C) after a heating process (100-120°C). Chlorella (air-dry matter) contained 934 g dry matter and 244 g essential amino acids (total)/kg. Chemical composition was hardly altered irrespective of the treatment. In the first experiment, pepsin digestibility of chlorella protein was determined in vitro. The cell rupture by high pressure homogenization caused a small but significant improvement in pepsin digestibility of chlorella protein compared with the control. In the second experiment, total tract apparent digestibilities of chlorella were determined in the rat. Digestibility of chlorella protein was significantly enhanced by high pressure homogenization, but the difference (88.6% vs. 87.4%, P < 0.01) due to treatment was small and similar to that observed in the in vitro experiment. These results suggested that Chlorella strain vulgaris: K-5 may be an efficient protein source even without cell rupture.     

5,7-Dodecadien-1-ol: Candidate for the Sex Pheromone of the Pine Moth

Ferredoxin-nitrite reductase (EC 1.7.7.1), an enzyme which catalyzes the 6-electron reduction of nitrite to ammonia, has been isolated from Spinacia oleracea. The isolated enzyme was homogeneous by disc electrophoresis with polyacrylamide gel. The molecular weight of the enzyme was estimated to be 86,000 by Ultrogel AcA 34 gel filtration. In the oxidized form, the enzyme had absorption maxima at 278, 388 (Soret band), 573 (α band) and 690 nm, indicating that siroheme is directly involved in the catalysis of nitrite reduction. This absorption spectrum was modified by sulfite, hydroxylamine and cyanide. The enzyme exhibited electron paramagnetic resonance signals with g values of 6.9 and 5.2, which are characteristic of a high spin Fe³⁺ -siroheme in the molecule. These signals disappeared upon the addition of dithionite or nitrite. This isolated enzyme also contained four moles of labile sulfide and 7 g-atoms of iron per 86,000 g of protein.     

Purging behaviors relate to impaired subjective sleep quality in female patients with anorexia nervosa: a prospective observational study

Background

We examined how purging behaviors relate to subjective sleep quality and sleep patterns and how symptoms of disordered eating behaviors relate to global sleep quality in female patients with anorexia nervosa (AN).

Methods

Participants were new consecutive female inpatients with a primary diagnosis of AN admitted to the Department of Psychosomatic Medicine at Kohnodai Hospital between June 26 and December 25, 2015. We recorded patients’ habitual eating behaviors, laxative overuse, or uretic misuse, and administered the Japanese versions of the Pittsburgh Sleep Quality Index (PSQI-J) and Center for Epidemiologic Studies Depression Scale. Raw PSQI-J data were used to determine sleep patterns (sleep-onset time, wake-up time, and sleep duration). To examine how purging behaviors related to sleep quality, we compared variables between AN restricting type (ANr) and AN binge-eating/purging type (ANbp). Spearman’s rank correlation analysis was used to examine which potential factors influence global PSQI-J score.

Results

Participants were 20 patients, of whom 12 had ANbp. Two ANr patients (25%) had global PSQI-J scores greater than 5, compared to 9 ANbp patients (75%; P < 0.05). Circadian rhythm disruption and abnormal sleep duration were significantly greater in ANbp patients than in ANr patients (P < 0.05). Global PSQI-J was significantly correlated with a diagnosis of ANbp (ρ = 0.525; P < 0.05), vomiting (ρ = 0.561; P < 0.05), and duration of illness (ρ = 0.536; P < 0.05).

Conclusions

ANbp patients had worse global sleep quality and greater disrupted sleep than did ANr patients. This suggests that treatments focusing on sleep would be useful, especially for ANbp patients. Furthermore, vomiting and duration of illness should be considered essential factors related to impaired global sleep quality.

Trial registration

Not applicable.

     

Elevated immunoreactive-somatostatin levels in the brain of ataxic mutant mice

Immunoreactive-somatostatin (IR-SRIF) levels were investigated in the brain of 4 types of ataxic mice (Rolling Mouse Nagoya, Weaver, PCD, Staggerer) with different cerebellar pathologies. IR-SRIF concentrations (ng/mg) were found to be significantly elevated in both cerebellum and cerebrum of all ataxic mutant mice, IR-SRIF (ng/organ) was found to be increased in the cerebellum and cerebrum in Rolling Mouse Nagoya and PCD compared with control mice. The gel-filtration profile (Sephadex G-50) in the cerebellar extracts of Rolling Mouse Nagoya proved to be identical to that of control mice. Three peaks of IR-SRIF were found to be uniformly elevated in Rolling Mouse Nagoya, with the highest peak coinciding with authentic somatostatin-14. The present results suggest that elevated levels of IR-SRIF in the brain may play a role in the mechanism underlying the manifestation of ataxia in ataxic mutant mice, especially in Rolling Mouse Nagoya and PCD.     

Enhancement of human cord blood CD34+ cell-derived NK cell cytotoxicity by dendritic cells

NK cells and dendritic cells (DCs) are both important in the innate host defense. However, the role of DCs in NK cell-mediated cytotoxicity is unclear. In this study, we designed two culture systems in which human cord blood CD34(+) cells from the same donor were induced to generate NK cells and DCs, respectively. Coculture of the NK cells with DCs resulted in significant enhancement of NK cell cytotoxicity and IFN-gamma production. However, NK cell cytotoxicity and IFN-gamma production were not increased when NK cells and DCs were grown together separated by a transwell membrane. Functional studies demonstrated that 1) concanamycin A, a selective inhibitor of perforin/granzyme B-based cytolysis, blocked DC-stimulated NK cytotoxicity against K562 cells; and 2) neutralizing mAb against Fas ligand (FasL) significantly reduced DC-stimulated NK cytotoxicity against Fas-positive Jurkat cells. In addition, a marked increase of FasL mRNA and FasL protein expression was observed in DC-stimulated NK cells. The addition of neutralizing mAb against IL-18 and IL-12 significantly suppressed DC-stimulated NK cell cytotoxicity. Neutralizing IFN-gamma Ab almost completely inhibited NK cell cytotoxicity against Jurkat cells. These observations suggest that DCs enhance NK cell cytotoxicity by up-regulating both perforin/granzyme B- and FasL/Fas-based pathways. Direct interaction between DCs and NK cells is necessary for DC-mediated enhancement of NK cell cytotoxicity. Furthermore, DC-derived IL-18 and IL-12 were involved in the up-regulation of NK cell cytotoxicity, and endogenous IFN-gamma production plays an important role in Fas-mediated cytotoxicity.     

Effect of temperature on the floral scent emission and endogenous volatile profile of Petunia axillaris

The floral scent emission and endogenous level of its components in Petunia axillaris under different conditions (20, 25, 30, and 35 degrees C) were investigated under the hypothesis that floral scent emission would be regulated by both metabolic and vaporization processes. The total endogenous amount of scent components decreased as the temperature increased, the total emission showing a peak at 30 degrees C. This decrease in endogenous amount was compensated for by increased vaporization, resulting in an increase of floral scent emission from 20 degrees C to 30 degrees C. The ambient temperature differently and independently influenced the metabolism and vaporization of the scent compounds, and differences in vapor pressure among the scent compounds were reduced as the temperature increased. These characteristics suggest the operation of an unknown regulator to change the vaporization of floral scent.     

A Novel Enhanced Green FluorescentProtein-Expressing NOG Mouse for Analyzingthe Microenvironment of Xenograft Tissues

The interaction between transplanted cells and host tissues is important for the growthand maintenance of transplanted cells. To analyze the mechanisms of these interactions, asystemic fluorescent protein-expressing mouse is a useful recipient. In this study, wegenerated a novel NOG strain, which strongly expresses enhanced green fluorescent protein(EGFP; PgkEGFP-NOG), especially in the liver, kidney, gastrointestinal tract, and testis.Because the host tissues expressed EGFP, xenotransplanted human cancer cells were clearlyidentified as EGFP-negative colonies in PgkEGFP-NOG mice. Immunohistochemical analysisrevealed that EGFP-expressing stromal tissues formed a complicated tumor microenvironmentwithin xenograft tissues. Moreover, a similar microenvironment was observed in human iPScell-derived teratomas. Collectively, these results indicated that a suitablemicroenvironment is essential for the growth and maintenance of xenotransplanted cells andthat PgkEGFP-NOG mice represent a useful animal model for analyzing the mechanisms ofmicroenvironment formation.     

Safety and immunogenicity of an AMA-1 malaria vaccine in Malian adults: results of a phase 1 randomized controlled trial

Background

The objective was to evaluate the safety, reactogenicity and immunogenicity of the AMA-1-based blood-stage malaria vaccine FMP2.1/AS02A in adults exposed to seasonal malaria.

Methodology/Principal Findings

A phase 1 double blind randomized controlled dose escalation trial was conducted in Bandiagara, Mali, West Africa, a rural town with intense seasonal transmission of Plasmodium falciparum malaria. The malaria vaccine FMP2.1/AS02A is a recombinant protein (FMP2.1) based on apical membrane antigen-1 (AMA-1) from the 3D7 clone of P. falciparum, adjuvanted with AS02A. The comparator vaccine was a cell-culture rabies virus vaccine (RabAvert). Sixty healthy, malaria-experienced adults aged 18–55 y were recruited into 2 cohorts and randomized to receive either a half dose or full dose of the malaria vaccine (FMP2.1 25 µg/AS02A 0.25 mL or FMP2.1 50 µg/AS02A 0.5 mL) or rabies vaccine given in 3 doses at 0, 1 and 2 mo, and were followed for 1 y. Solicited symptoms were assessed for 7 d and unsolicited symptoms for 30 d after each vaccination. Serious adverse events were assessed throughout the study. Titers of anti-AMA-1 antibodies were measured by ELISA and P. falciparum growth inhibition assays were performed on sera collected at pre- and post-vaccination time points. Transient local pain and swelling were common and more frequent in both malaria vaccine dosage groups than in the comparator group. Anti-AMA-1 antibodies increased significantly in both malaria vaccine groups, peaking at nearly 5-fold and more than 6-fold higher than baseline in the half-dose and full-dose groups, respectively.

Conclusion/Significance

The FMP2.1/AS02A vaccine had a good safety profile, was well-tolerated, and was highly immunogenic in malaria-exposed adults. This malaria vaccine is being evaluated in Phase 1 and 2 trials in children at this site.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00308061","term_id":"NCT00308061"}}NCT00308061