Measurement of 15N-1H coupling constants in uniformly 15N-labeled proteins: Application to the photoactive yellow protein

A modified HNHB experiment is presented that allows thedetermination of J(NH) coupling constants directly from the ratio ofcross-peak to diagonal-peak intensities. The experiment was applied to thephotoactive yellow protein (PYP) and yielded the magnitude of 117³J(NH) coupling constants. In addition, 29³J(NH^(i–1)) coupling constantscould be measured, providing information about the backbone angle .These data, in conjunction with the magnitudes of the³J(H^NH) coupling constantsobtained from the HNHA spectrum, effectively discriminate the twopossibilities for the stereospecific assignment of theH resonances in glycine residues. For all eight glycineresidues in PYP that were not subject to conformational averaging and hadnon-degenerate H resonance frequencies, the J-couplingdata, together with limited NOE data, yielded the stereospecific assignmentof the H resonances for these residues. In addition,reliable and precise , dihedral constraints were also derived forthese residues from the J-coupling data.     

Oleic Acid Inhibits Gap Junction Permeability and Increases Glucose Uptake in Cultured Rat Astrocytes

Abstract: The role of oleic acid in the modulation of gap junction permeability was studied in cultured rat astrocytes by the scrape-loading/Lucifer yellow transfer technique. Incubation with oleic acid caused a dose-dependent inhibition of gap junction permeability by 79.5% at 50 µ M , and no further inhibition was observed by increasing the oleic acid concentration to 100 µ M . The oleic acid-mediated inhibition of gap junction permeability was reversible and was prevented by bovine serum albumin. The potency of oleic acid-related compounds in inhibiting gap junction permeability was arachidonic acid > oleic acid > oleyl alcohol > palmitoleic acid > stearic acid > octanol > caprylic acid > palmitic acid > methyloleyl ester. Oleic acid and arachidonic acid, but not methyloleyl ester, increased glucose uptake by astrocytes. Neither oleic acid nor arachidonic acid increased glucose uptake in the poorly coupled glioma C6 cells. These results support that the inhibition of gap junction permeability is associated with the increase in glucose uptake. We suggest that oleic acid may be a physiological mediator of the transduction pathway leading to the inhibition of intercellular communication.     

Short-term variations in catches of the pea moth,Cydia nigricana, in interacting pheromone traps

Short-term variations in the relative catch in each of two or three interacting pheromone traps for the pea moth,Cydia nigricana (F.), were investigated for traps aligned along the wind. The proportional catch in each trap varied widely, although the mean values accorded with previous estimates. Over consecutive short intervals during a single trapping period the proportion caught in the centre trap of a three-trap line was constant. The proportion caught in the upwind trap of two-and three-trap lines showed trends in time. These trends differed between trapping periods, but two lines of traps operated simultaneously gave similar results to each other. It is suggested that these results, which are predicted by a model based on various components of moth orientation behaviour, are caused by changes in systematic behavioural processes, not random effects. Possible mechanisms are discussed.

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Variations à court terme des captures deCydia nigricana dans des pièges à phéromones en interaction

Résumé Des données antérieures concernant les interactions entre des pièges à phéromone alignés le long du vent ont été utilisées pour déduire les caractéristiques du comportement d'orientation deC. nigricana. Ces données ont été introduites dans un modèle de simulation quantitative qui prédisait que quand les captures totales sur une ligne ont été regroupées sur une période globale de piégage, la proportion capturée dans chaque piège devrait aussi avoir des valeurs moyennes semblables, mais varie plus largement que précédemment indiqué. Les simulations concernant des intervalles consécutifs beaucoup plus courts pendant la même période de piégage ont suggéré une forme spécifique de cette variation.Cette note signale des variations à court terme dans la proportion capturée au piège qui confirment ces prédictions. Nous montrons que sur des intervalles consécutifs brefs pendant une simple période de piégage, la proportion capturée dans le piège central d'une ligne de 3 pièges est contstante, bien que sa valeur change suivant les périodes de piégage. La proportion capturée dans le piège face au vent de 2 ou 3 lignes de pièges suit cette tendance dans le temps, ce qui est généralement bien représenté avec des courbes simples. Ces tendances changent suivant les périodes de piégage, mais des lignes de pièges fonctionnant simultanément fournissaient des résultats similaires. On suggère que ces résultats sont dus à des changements dans des processus comportementaux systématiques et non à des effects aléatoires. Les mécanismes possibles sont discutés.

     

Role of three basic light reactions in photomovement of desmids

Photoaccumulations in light trap experiments have been studied in the desmids, Cosmarium, Micrasterias and Euastrum. Dependence of accumulation density on exposure time follows saturation curves, while dose response curves show optima. Time-lapse microcinematography and population methods have revealed that all three basic light-induced motor responses known in microorganisms participate in producing photoaccumulations in desmids. During the initial phase the cells are phototactically attracted towards the trap by scattered light. In low light intensity traps photokinetic reactions may play only a minor role, since photokinesis could be evoked only by light intensities100 lx in Cosmarium cucumis. True photophobic reactions have been demonstrated for the first time in desmids. There are two types of phobic responses in desmids: either the cell reverses its movement or it swings sidewise into the new direction. Behaviour of partially shadowed cells suggests that perception of light direction is brough about by simultaneous intensity measurement at two or more sites within the cell.     

Hydroxamic acids affecting barley yellow dwarf virus transmission by the aphid Rhopalosiphum padi

2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), a hydroxamic acid (Hx) occurring in wheat, was shown to deter feeding by the aphid Rhopalosiphum padi (L.), and to reduce BYDV transmission to the plant. Dual choice tests with wheat leaves showed the preferential settlement of aphids on leaves with lower levels of DIMBOA. Electric monitoring of aphid feeding behaviour showed that in seedlings with higher DIMBOA levels fewer aphids reached the phloem and they needed longer times to contact a phloem vessel than in those with lower levels. When aphids carrying BYDV were allowed to feed on wheat cultivars with different DIMBOA levels, fewer plants were infected with BYDV in the higher DIMBOA cultivars than in the lower ones. Preliminary field experiments showed a tendency for wheat cultivars with higher Hx levels to be more tolerant to infection by BYDV than lower Hx level ones.     

应用免疫电镜技术快速检测菜豆黄花叶病毒、马铃薯M病毒和燕麦花叶病毒

应用免疫吸附电流技术(ISEM)可有效地检测腐汁液中的菜豆黄花叶病毒(BYMV)、马铃薯M病毒(PVM)和燕麦花叶病毒(OMV)。BYMV,PVM和OMV三种抗血清的适宜工作浓度和对铜网的适宜包被时间均为1000倍和1小时,对同源病毒的适宜捕获时间分别为4℃下2、2和8小时。PVM和OMV的病汁液检测灵敏度均为稀释4000倍,而BYMV病汁液稀释16000倍时还能检测到少量病毒料子。ISEM捕获法和修饰法的结果表明,这三种病毒之间无血清学交叉反应。     

Rubus host range of rubus yellow net virus and its involvement with other aphid-borne latent viruses in inducing raspberry veinbanding mosaic disease

After graft inoculation with rubus yellow net virus (RYNV), 12 of 34 Rubus species and cultivars developed noticeable symptoms. R. macraei developed the most conspicuous symptoms and is recommended as an improved indicator plant. In attempts to determine the cause of raspberry veinbanding mosaic, a disease in which RYNV is involved, several European and North American red raspberry cvs were graft-inoculated with RYNV and three other aphid-borne viruses, black raspberry necrosis (BRNV), raspberry leaf mottle (RLMV) and raspberry leaf spot, singly and in all combinations. In periods of up to 4 yr, classical veinbanding mosaic symptoms developed in sensitive cvs only when they contained both RYNV and RLMV. These symptoms were intensified in plants co-infected with additional viruses. Veinbanding mosaic disease did not develop in any of 11 cvs infected with RYNV + BRNV, the combination of viruses previously assumed to be responsible for this disease in Britain and North America.     

INTERACTIONS BETWEEN KURIL SEALS AND SALMON TRAP NET FISHERY IN THE COASTAL WATERS OF SOUTHEASTERN HOKKAIDO

An annual average of 163 Kuril seals was found dead in two years in salmon trap nets along the coastal waters of the Nemuro Peninsula and adjacent areas. The seal-caused damage to the total salmon catch at the salmon trap nets was concentrated in some of them, particularly No. 27, where seals killed or injured 5.1% of the catch in 1982, and 1.8% in 1983. Based on the proportion of Kuril seals among the dead seals in the trap nets, it was estimated that Kuril seals damaged 4.7% of the total salmon catch at No. 27 in 1982, and 1.7% in 1983. Not all seals that entered the trap net drowned; some killed or damaged salmon, and then escaped.