Characterization of protein kinases from bovine parotid glands. The effect of tolbutamide and its derivative on these partially purified enzymes.

1. Four fractions of protein kinase (EC 2.7.1.37) activity (Peak IH, IIH, IIIC and IVC) have been resolved and partially purified from the 100 000 X g supernatant fraction of bovine parotid glands by DEAE-cellulose and phosphocellulose chromatographies. 2. The protein kinases of Peak IH and IIH were adenosine 3',5'-monophosphate (cyclic AMP) -dependent and had similar enzymic properties. The enzyme activities of Peak IIIC and IVC were cyclic-AMP independent, but there were some distinct differences between their properties. The protein kinase in Peak IIIC was activated by 0.2 M NaCl or KCl and phosphorylated casein preferentially as the substrate, utilizing only ATP as a phosphate donor. On the other hand, the protein kinase in Peak IVC was inhibited by univalent salts and preferred phosvitin to casein, utilizing either ATP or GTP as a phosphate donor. 3. Tolbutamide increased the Km value for ATP and the dissociation constant for cyclic AMP, resulting in the inhibition of cyclic-AMP dependent protein kinase activity in the presence of cyclic AMP. Tolbtamide and its carboxy derivative, 1-butyl-3-p-carboxyphenylsulfonylurea, exerted almost no inhibitory effect on either the cyclic-AMP dependent protein kinase activities in the absence of cyclic AMP or on the cyclic-AMP independent protein kinase activities.     

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.     

Synthetic oligodeoxyribonucleotides showing abnormal mobilities on polyacrylamide gel electrophoresis

We found that synthetic DNA fragments containing a GCGAAAGC sequence showed higher mobilities than oligonucleotides without the sequence on denaturing polyacrylamide gel electrophoresis. For example, the fragment, GCGAAAGCT (9mer), showed higher mobility than the corresponding 8mer (CGAAAGCT). In addition, on Maxam-Gilbert sequencing, a 21mer containing the GCGAAAGC sequence showed an abnormal pattern, which were similar to those due to compression observed on sequencing of DNAs with high GC contents, as recently reported. It was suggested that this compression was due to the increased mobilities of the specific fragments with the GCGAAAGC sequence and that these fragments took on abnormal conformations.     

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.