Kinetic study of isomerization of ferricytochrome c at alkaline pH

Kinetic studies of the isomerization reaction of horse heart ferricytochrome c between pH 8.5 and pH 12.1 have been carried out by using stopped-flow and rapid scanning stopped-flow techniques. Below pH 10, our results were in good agreement with the scheme proposed earlier (Davis, L. A., Schejter, A. and Hess, G. P. (1974) J. Biol. Chem. 249, 2624–2632). Above pH 10, another faster first-order process was observed, which suggested the existence of a transient species in the isomerization reaction between the species with and without a 695 nm band. The probable scheme of the isomerization reaction is considered to be

where H denotes a proton, the colored forms are the species predominant at neutral pH with a 695 nm band and the noncolored forms are the species without a 695 nm band. The transient species has a small 695 nm absorbance which suggests that the sixth ligand is still Met-80, although the protein conformation might be different from that at neutral pH.     

Response of isolated rat iris dilator to adrenergic and cholinergic agents and electrical stimulation

Responses of isolated rat iris dilator to some agents and to electrical stimulation were examined. Norepinephrine and epinephrine produced contraction, which was antagonized by 0.03 μM phentolamine. Acetylcholine produced relaxation at low concentrations (1 nM ? 1 μM) as great as 80 % of the resting tone while contraction at high concentrations (≥1 μM). Both responses were suppressed by 0.02 μM atropine and enhanced by 0.03 μM physostigmine. Electrical stimulation at low voltage or low frequency (up to 10 Hz) elicited relaxation while stimulation at high voltage or high frequency (30 Hz) produced contraction. Stimulation with intermediate strength elicited biphasic response. The contraction and relaxation induced by electrical stimulation were abolished by 3 μM phentolamine or by 0.05 μM atropine, respectively. Both phases were abolished by tetrodotoxin (0.3 μM). It is suggested that in the rat the cholinergic relaxation of the dilator may assist the cholinergic contraction of the sphincter (1). The pronounced cholinergic relaxation of nonvascular tissue is to be noted.     

Taxonomic review of the lace bug genus Omoplax (Hemiptera: Heteroptera: Tingidae) endemic to “Oriental Galapagos” (the Ogasawara Islands,Japan) with the description of its new allied genus and species

In this study, we revise the lace bugs (family Tingidae) from the Ogasawara Islands, Japan (also known as the “Oriental Galapagos”). Three species belonging to two endemic genera are recognized: Acanthomoplax tomokunii gen. et sp. nov. , Omoplax desecta (Horváth, 1912), and O. majorcarinae Guilbert, 2001. A key to species is provided to facilitate the identification of Ogasawaran lace bugs.     

Impact of Noncovalent Sulfur–Fluorine Interaction Position on Properties,Structures, and Photovoltaic Performance in Naphthobisthiadiazole‐Based Semiconducting Polymers

Controlling the energetics and backbone order of semiconducting polymers is essential for the performance improvement of polymer‐based solar cells. The use of fluorine as the substituent for the backbone is known to effectively deepen the molecular orbital energy levels and coplanarize the backbone by noncovalent interactions with sulfur of the thiophene ring. In this work, novel semiconducting polymers are designed and synthesized based on difluoronaphthobisthiadiazole (FNTz) as a new family of naphthobisthiadiazole (NTz)–quaterthiophene copolymer systems, which are one of the highest performing polymers in solar cells. The effect of the fluorination position on the energetics and backbone order is systematically studied. It is found that the dependence of the solar cell fill factor on the active layer thickness is very sensitive to the fluorination position. It is thus further investigated and discussed how the structural features of the polymers influence the photovoltaic parameters as well as the diode characteristics and bimolecular recombination. Further, the polymer with fluorine on both the naphthobisthiadiazole and quaterthiophene moieties exhibits a quite high power conversion efficiency of 10.8% in solar cells in combination with a fullerene. It is believed that the results would offer new insights into the development of semiconducting polymers.     

Extreme storms cause rapid but short-lived shifts in nearshore subtropical bacterial communities

Climate change scenarios predict tropical cyclones will increase in both frequency and intensity, which will escalate the amount of terrestrial run-off and mechanical disruption affecting coastal ecosystems. Bacteria are key contributors to ecosystem functioning, but relatively little is known about how they respond to extreme storm events, particularly in nearshore subtropical regions. In this study, we combine field observations and mesocosm experiments to assess bacterial community dynamics and changes in physicochemical properties during early- and late-season tropical cyclones affecting Okinawa, Japan. Storms caused large and fast influxes of freshwater and terrestrial sediment – locally known as red soil pollution – and caused moderate increases of macronutrients, especially SiO₂ and PO₄³⁻, with up to 25 and 0.5 μM respectively. We detected shifts in relative abundances of marine and terrestrially derived bacteria, including putative coral and human pathogens, during storm events. Soil input alone did not substantially affect marine bacterial communities in mesocosms, indicating that other components of run-off or other storm effects likely exert a larger influence on bacterial communities. The storm effects were short-lived and bacterial communities quickly recovered following both storm events. The early- and late-season storms caused different physicochemical and bacterial community changes, demonstrating the context-dependency of extreme storm responses in a subtropical coastal ecosystem.     

Population abundance gradient of Inurois punctigera along altitude

A winter geometrid moth, Inurois punctigera, shows sympatric and genetically isolated seasonal populations (i.e. early‐ and late‐winter populations) in the cold regions of Japan, whereas it shows only mid‐winter populations in the warm regions. Variation in adult flight phenology on a large geographic scale along latitudinal environmental gradients has been described, but the phenological variation on a more local scale along altitudinal environmental gradients has not yet been characterized. In the present study, we assessed the flight phenology at high‐ and low‐elevation areas in Mt. Rokko, Hyogo, Japan. First, we revealed that flight period was not disrupted in mid‐winter, even at high‐elevation areas (>660 m) but the population abundance was much lower in high‐elevation areas than in low‐elevation areas. Then, in the following two seasons, we investigated I. punctigera abundance, winter harshness (i.e. winter temperature) and their host plant abundance in nine closely located stations in Mt. Rokko. A generalized linear mixed model analysis indicated a greater effect of winter temperature on I. punctigera abundance compared to available food resources, suggesting that differences in winter harshness among elevation shapes the gradient of I. punctigera abundance along altitude. Our findings suggest that harsh conditions during winter function as selective agents on mid‐winter types of I. punctigera, and this could be involved in the divergence between sympatric early‐ and late‐winter populations of I. punctigera.     

Where should wild species be sampled? New method based on isolation‐by‐distance objectively gives the answer

Random sampling is an important statistical assumption, but virtually impossible when sampling a wild species as we cannot know where all the individuals exist. While interpopulation or intrataxa sampling methods have been developed, there are currently few intrataxon sampling methods to objectively decide where to sample wild taxa. We suggest a new sampling method which computes appropriate sampling locations from coordinates, assuming geographical autocorrelation of phylogeny within a taxon (isolation‐by‐distance). The computed locations encompass the highest genetic diversity, providing a genetically representative sample. In addition, it can utilize presence/absence information during sampling to reoptimize sampling scheme. Comparing to the single existing method of the similar purpose, the merits of ours is unnecessity of environmental data resulting in easy application, and is theoretically deduced. We tested this method using published phylogeographical data. The test result was generally encouraging, but the method failed where species showed uniform genetic structure or recent distribution expansion which violate the assumption of geographical autocorrelation of phylogeny. Though simple, our method constructs a methodological and statistical foundation for sampling wild species, and is applicable to revising taxonomic study and conservation biology.     

Induced pluripotent stem cell‐derived myeloid cells expressing OX40 ligand amplify antigen‐specific T cells in advanced melanoma

Immune checkpoint inhibitors improved the survival rate of patients with unresectable melanoma. However, some patients do not respond, and variable immune‐related adverse events have been reported. Therefore, more effective and antigen‐specific immune therapies are urgently needed. We previously reported the efficacy of an immune cell therapy with immortalized myeloid cells derived from induced pluripotent stem cells (iPS‐ML). In this study, we generated OX40L‐overexpressing iPS‐ML (iPS‐ML‐Zsgreen‐OX40L) and investigated their characteristics and in vivo efficacy against mouse melanoma. We found that iPS‐ML‐Zsgreen‐OX40L suppressed the progression of B16‐BL6 melanoma, and prolonged survival of mice with ovalbumin (OVA)‐expressing B16 melanoma (MO4). The number of antigen‐specific CD8⁺ T cells was higher in spleen cells treated with OVA peptide‐pulsed iPS‐ML‐Zsgreen‐OX40L than in those without OX40L. The OVA peptide‐pulsed iPS‐ML‐Zsgreen‐OX40L significantly increased the number of tumor‐infiltrating T lymphocytes (TILs) in MO4 tumor. Flow cytometry showed decreased regulatory T cells but increased effector and effector memory T cells among the TILs. Although we plan to use allogeneic iPS‐ML in the clinical applications, iPS‐ML showed the tumorgenicity in the syngeneic mice model. Incorporating the suicide gene is necessary to ensure the safety in the future study. Collectively, these results indicate that iPS‐ML‐Zsgreen‐OX40L therapy might be a new method for antigen‐specific cancer immunotherapy.