Combined effect of cyprid age and lipid content on larval attachment and metamorphosis of Balanus amphitrite darwin

Various algal diets of different lipid content and composition were used to rear batches of naupliar larvae of Balanus amphitrite. The cyprids in these larval batches differed in lipid content and were used to investigate the combined effect of cyprid lipid content and cyprid age on attachment and metamorphosis. For this purpose, cyprids were aged for 0,3 and 6 d at 8°C prior to utilization in laboratory attachment assays. The percentage attachment of cyprids with similar lipid content differed significantly among the three age categories. A strong and a weak positive relationship between cyprid lipid content and attachment were monitored in young and old cyprids, respectively. A significant interaction (two‐way ANOVA) between cyprid age and lipid content was observed, indicating that these factors jointly affect larval attachment and metamorphosis in B. amphitrite from the beginning of the cyprid stage.     

Effect of cyprid age on the settlement of balanus amphitrite darwin in response to natural biofilms

Larval settlement of the barnacle Balanus amphitrite Darwin (Cirripedia, Balanidae) is influenced by natural biofilms. In previous work by others, discriminatory settlement of aged cyprids has been observed in response to biofilms of different age. This study extends prior work by considering the effect of the age of cyprids on the outcome of settlement assays. Settlement was investigated with 0‐day‐old (newly metamorphosed) and 5‐day‐old cyprids. Biofilms under investigation were developed in the field for periods of 5 d and 1 month, and were subsequently included in laboratory settlement assays with a choice between a filmed and an unfilmed substratum. The bioassay was modified from the conventional horizontal dish design in order to generate a low water surface‐to‐volume ratio, which served to suppress larval entrapment in an organic layer on the water surface. Irrespective of cyprid age, a clear discrimination between a filmed and an unfilmed substrata was observed, and the preference for filmed or unfilmed substratum was dependent on the age of the cyprids. Settlement of 0‐day‐old cyprids was inhibited by a biofilmed substratum whereas induction occurred with aged cyprids. This pattern of settlement was independent of biofilm age. Bacterial abundance on unfilmed substrata in treatments and controls was significantly lower than that on biofilmed surfaces, confirming that bacterial contamination did not change the qualitative option during the assay.     

Molecular dynamics simulations of carbon nanotube oscillators deformed by encapsulated copper nanowires

Pure carbon nanotube (CNT) oscillators are compared to the corresponding CNT oscillators encapsulating copper nanowires (Cu@CNTs) by molecular dynamics simulations. The classical oscillation theory provides a fairly good estimate of the mass dependence of the operating frequency when the CNT surface is not deformed by the Cu nanowire. The structural deformations of the CNT induced by the encapsulated copper nanowire have a greater effect on the oscillation frequency than the mass of the copper nanowire. The excess forces of the Cu@CNT oscillator are slightly higher than those of the CNT oscillator and the excess van der Waals forces induced by the inter-wall interactions are 17 times higher than the excess forces induced by the Cu nanowire–CNT interactions.     

Masking the mask: An Israeli response to the threat of chemical warfare

This paper analyzes a form of visual euphemism which we call “masking the mask.” During the Gulf War, Iraq fired 40 missiles on Israel. Citizens were issued with gas mask kits and were ordered into sealed rooms in their homes during attacks. Thousands of Israelis of all ages decorated or covered their gas mask kits. Although no chemical warheads were fired on the country, Israelis were unusually fearful of gassing because of associations with the Holocaust. Masking the mask served important psychological and communicative functions. It provided a means to express one's fears, to attempt a modest form of mastery over a threatening environment, as well as to rebel against dehumanization and personalization, and to express solidarity with the group under threat, while reasserting one's individual identity.     

Stereoselective Interaction Between Tetrahydropalmatine Enantiomers and CYP Enzymes in Human Liver Microsomes

Tetrahydropalmatine (THP), with one chiral center, is an alkaloid that possesses analgesic and many other pharmacological actives. The aim of the present study is to investigate stereoselective metabolism of THP enantiomers in human liver microsomes (HLM) and elucidate which cytochrome P450 (CYP) isoforms contribute to the stereoselective metabolism in HLM. Additionally, the inhibitions of THP enantiomers on activity of CYP enzymes are also investigated. The results demonstrated that (+)‐THP was preferentially metabolized by HLM. Ketoconazole (inhibitor of CYP3A4/5) inhibited metabolism of (?)‐THP or (+)‐THP at same degree, whereas the inhibition of fluvoxamine (inhibitor of CYP1A2) on metabolism of (+)‐THP was greater than that of (?)‐THP; moreover, the metabolic rate of (+)‐THP was 5.3‐fold of (?)‐THP in recombinant human CYP1A2. Meanwhile, THP enantiomers did not show obvious inhibitory effect on the activity of various CYP isoforms (CYP1A2, 2A6, 2C8, 2C9, 2C19, 2E1, and 3A4/5), whereas (?)‐THP, but not (+)‐THP, significantly inhibited the activity of CYP2D6 with the Ki value of 6.42 ± 0.38 μM. The results suggested that THP enantiomers were predominantly metabolized by CYP3A4/5 and CYP1A2 in HLM, and (+)‐THP was preferentially metabolized by CYP1A2, whereas CYP3A4/5 contributed equally to metabolism of (?)‐THP or (+)‐THP. Besides, the inhibition of CYP2D6 by (?)‐THP may cause drug–drug interaction, which should be considered. Chirality 25:43–47, 2013. © 2012 Wiley Periodicals, Inc.     

IgE production in CD40/CD40L cross-talk of B and mast cells and mediator release via TGase 2 in mouse allergic asthma

TGase 2 is over-expressed in a variety of inflammatory diseases including allergic asthma. This study aimed to investigate the role of TGase 2 on IgE production and signaling pathways in mast cell activation related to OVA-induced allergic asthma. Bone marrow-derived mast cells (BMMCs) isolated from WT or TGase 2^?/? mice were activated with Ag/Ab (refer to act-WT-BMMCs and act-KO-BMMCs, respectively). B cells isolated from splenocytes were activated with anti-mouse IgM (act-B cells), and B cells were co-cultured with BMMCs. WT and TGase 2^?/? mice were sensitized and challenged with OVA adsorbed in alum hydroxide. Intracellular Ca^2 + ([Ca^2 +]_i) levels were determined by fluorescence intensity; IgE, mediators and TGase 2 activity by ELISA; the CD138 expression by FACS analyzer; cell surface markers and signal molecules by Western blot; NF-κB by EMSA; co-localization of mast cells and B cells by immunohistochemistry; Fcε RI-mediated mast cell activation by PCA test; expression of cytokines, MMPs, TIMPs, TLR2 and Fc?RI by RT-PCR. In vitro, act-KO-BMMCs reduced the [Ca^2 +]i levels, NF-κB activity, expression of CD40/CD40L, plasma cells, total IgE levels and TGase 2 activity in act-B cells co-cultured with act-BMMCs, expression of inflammatory cytokines and MMPs2/9, release of mediators (TNF-α, LTs and cytokines), and activities of signal molecules (PKCs, MAP kinases, I-κB and PLA2), which were all increased in act-WT-BMMCs. TGase 2 siRNA transfected/activated-BMMCs reduced all responses as same as those in act-KO-BMMCs. In allergic asthma model, TGase 2^?/? mice protected against PCA reaction, OVA-specific IgE production and AHR, and they reduced co-localization of mast cells and B cells or IgE in lung tissues, expression and co-localization of surface molecules in mast cells (c-kit and CD40L) and B cells (CD23 and CD40), inflammatory cells including mast cells, goblet cells, amounts of collagen and mediator release in BAL fluid and/or lung tissues, which were all increased in WT mice. TLR expression in TGase 2^?/? mice did not differ from those in WT mice. Our data suggest that TGase 2 expression and Ca^2 + influx required by bidirectional events in mast cell activation facilitate IgE production in B cells via up-regulating mast cell CD40L expression, and induce the expression of numerous signaling molecules associated with airway inflammation and remodeling in allergic asthma.