Coexistence of β1- and β2-Adrenoceptors in the Melanophore of the Goby Tridentiger obscurus*

The effects of β-adrenergic agonists and antagonists on the pigmentary state of denervated melanophores in isolated, split, caudal fins of the goby Tridentiger obscurus were examined to investigate the function and the subtype of the β-adrenoceptors of the melanophores. Salbutamol, terbutaline, and dobutamine partially inhibited the pigment-aggregating response of melanophores to norepinephrine. The effects of these β-agonists were inhibited by propranolol. It was confirmed that the melanophores possess both α-and β-adrenoceptors, and that the activation of the β-adrenoceptors induces the dispersion of pigment in the melanophores. Norepinephrine, epinephrine, isoproterenol, dobutamine, salbutamol, and terbutaline evoked the dispersion of pigment in the melanophores in which pigment had previously been aggregated by treatment with verapamil in the presence of phentolamine. The pigment-dispersing effects of two β₁-selective agonists, norepinephrine and dobutamine, were effectively inhibited by metoprolol, a selective antagonist of β₁-receptors. By contrast, the pigment-dispersing effects of two β₂-selective agonists, salbutamol and terbutaline, were not inhibited by metoprolol. Both the effects of nonselective agonists, epinephrine and isoproterenol, were partially inhibited by metoprolol. The actions of all of the β-agonists used were effectively inhibited by propranolol, and they were partially inhibited by butoxamine. These results suggest coexistence of β₁- and β₂-adrenoceptors in the melanophores. The relative numbers of β₁- and β₂-adrenoreceptors as a percentage of the total population of β-adrenoceptors were estimated to be 18.6% and 81.4%, respectively, from analyses of Hofstee plots of the effects of the β-agonists on the melanophores in the presence of butoxamine or metoprolol.     

Action Spectra for Step-Up Photophobic Response in Blepharisma

ABSTRACT The cells of Blepharisma which possess red pigment (blepharismin) show step-up photophobic response (temporal ciliary reversal induced by a sudden increase in light intensity). Bleaching of the cells by cold shock raised a threshold light intensity for the response, Oxidation of red pigment that produced blue pigment did not raise the threshold for the response. The action spectrum for the step-up photophobic response of the cells which possess normal red pigment had peaks at about 580, 540 and 490 nm, a value which coincided with peaks of an absorption spectrum of the red pigment. The absorption spectrum of oxidized pigment (blue pigment) shifted 20 nm toward infrared light. The action spectrum for the response of the cells which possess blue pigment also shifted 20 nm toward infrared light. Results suggest that red pigment might be involved in the step-up photophobic response. Key words. Blepharismin, ciliary reversal, photoreceptors, photoresponse.     

Induction of DNA synthesis by 2,4-dichlorophenoxyacetic acid during callus induction in Jerusalem artichoke tuber tissues

During the induction of DNA synthesis in Jerusalem artichoke (Helianthus tuberosus L.) tuber by 2,4-D, the 2-¹⁴C-2, 4-D from the agar medium rapidly incorporated into the ethanol soluble and insoluble fractions. Although the 2,4-D level in the ethanol soluble fraction decreased on transplantation of the tissue from the 2-¹⁴C-2,4-D medium to medium without the auxin, its level in the buffer-soluble and -insoluble macromolecular fractions increased. The purified, buffer-insoluble macromolecules were chromatin. The 2,4-D binding to chromatin particularly increased during DNA synthesis. The histone contents of chromatin decreased as DNA synthesis progressed. The polyacrylamide gel electrophoretic patterns of the histones showed a decrease in the moderately lysine-rich histone fraction as compared to other fractions. Thus, the decrease in the histone level caused by 2,4-D and the presence of the 2,4-D moderately lysine-rich histone complex may be closely related to the induction of DNA synthesis by 2,4-D in cells.     

Control of Tissue Specificity: The Pattern of Cellular Synthetic Activities in Tissue Transformation

During transformation of the dorsal marginal iris into lenstissue after removal of the lens in the adult newt, the cellsundergo gradual changes in synthetic activities. Autoradiographicdata indicate an enhancement of RNA synthesis in the nucleusof iris cells, which is followed by enhancement of protein synthesisand onset ot DNA synthesis. After discharge of pigment granulesand a period of cellular multiplication accompanied by ribosomeproduction, the cells stop DNA synthesis and start to show detectableamounts of lens-specific proteins (-,ß-, and -crystallins).This time coincides with initiation of differentiation of primarylens fibers. In the later stages of regeneration, - and ß-crystallinsare present in the dividing cells of the lens epithelium, aswell as in the cells of the fiber area, but -crystallins aredetected only in Che cells of the fiber area. The data wereinterpreted as suggesting that the gene utilization patterntypical for the iris is not directly converted into that forthe lens, but goes through intermediate patterns before thetissue transformation is completed.     

First record of the genus Buchananiella Reuter (Heteroptera: Anthocoridae) from Japan, with description of a new species

Two species of the anthocorid genus Buchananiella Reuter are recorded from Japan for the first time. Buchananiella leptocephala sp. nov. is described here based on specimens from Honshu and the Ryukyus. Buchananiella crassicornis Carayon, hitherto known from the Ivory Coast and India, was found in the Ryukyus.     

The non-virus proteins associated with tobacco mosaic virus

1. Exhaustive fractionation of leaves from tobacco plants systemically infected with TMV has led to the isolation of two non-virus proteins, B3 and B6, and the detection of a third, A4, which do not occur in comparable uninfected plants. 2. Components B3 and B6 have been found consistently in a series of ten extracts from plants grown over an 18 month period in all seasons of the year. It is concluded that these components are as characteristic of the infected plant as TMV itself. 3. As they occur in the initial extracts, the non-virus proteins are of low molecular weight (S₂₀ ca. 3). On treatment, each component tends to form a high molecular weight polymer with an electrophoretic mobility considerably greater than that of the starting material. The high molecular weight derivatives of A4, B3, and B6 have been designated A8, B8, and B7 respectively. There is no evidence that these high molecular weight components occur as such in the infected leaf. 4. The non-virus proteins are free of nucleic acid and are not infectious. They cross-react immunochemically with TMV. 5. Compared with TMV content, the amounts of the non-virus proteins found in infected leaf are relatively small, falling in the range of 10 to 150 micrograms per gm. of tissue.     

不同水肥条件下番茄土壤微生物群落多样性及其与产量品质的关系

采用内含子切接点引物 (Intron-splice junction primer) 和长随机引物的PCR (Polymerase chain reaction, 聚合酶链) 标记技术, 就黄土高原不同水肥处理对日光温室番茄土壤微生物群落多样性进行了研究, 并对产量、品质的影响进行了分析。结果表明, 所用的6个引物共能扩增出182条稳定清晰的条带, 其中142条为多态性条带, 多态性条带为78.02%。聚类分析与主坐标分析表明, 水肥对土壤微生物群落多样性的变化有不同的影响。土壤微生物群落多样性指数与番茄产量、果实的Vc、可溶性蛋白质含量成正相关, 尤其与Vc的相关系数达0.9211, 而与可溶性固形物含量成负相关关系。6个水肥组合中WmFh (中水高肥) 土壤微生物群落多样性指数最高, 且番茄果实的Vc、可溶性蛋白质含量及产量显著高于其他处理, 可溶性固形物含量较低。该组合有利于土壤微生物群落的多样性和稳定性的提高, 利于土壤生态环境的改善和番茄优良品质的形成。