Effect of SO(2) and O(3) on Production of Antioxidants in Conifers

Production of antioxidants was investigated in needles of fir (Abies alba Mill.) and spruce (Picea abies (L.) Karst) after exposure to low concentrations of SO₂, O₃, and a combination of both pollutants. Glutathione reacted most sensitively to pollutants followed by vitamin E and vitamin C. In spruce needles, the overall increase of antioxidants after exposure to air pollutants was lower than in needles of fir. SO₂ was more potent than O₃. Maximum increase of antioxidants was found in needles after exposure of trees to SO₂ + O₃.     

Electron spin resonance evidence for the formation of free radicals in plants exposed to ozone

Electron spin resonance (ESR) spectroscopy was used to demonstrate that free radicals are formed in O₃-fumigated plant leaves prior to the formation of visible leaf injury. ESR signals with a g-value of 2.0037 to 2.0043, were observed in pea ( Pisum sativum L. cv. Feltham first) and bean ( Phaseolus vulgaris L. cv. Pinto) plants that had been fumigated for 4 h with 70–300 nl l⁻¹ of ozone after they had been treated with the spin-trap N- t -butyl-α-phenylnitrone (PBN). The size of the ESR signals increased with the concentration of ozone used but the nature of the trapped radicals could not be identified. However, further experiments using an inhibitor of ethylene biosynthesis, arninoethoxyvinyl glycine (AVG), showed that the reaction between ozone and ethylene is the cause for ozone toxicity.     

Subject: Navigation and orientation

Research Notes on Avian Biology 1994: Selected Contributions from the 21st International Ornithological CongressMorphology and Physiology: Orientation

Subject: Navigation and orientation     

世居及移居高原青少年最大有氧能力的特征

本文报道海拔３４１７ｍ和４２８０ｍ地区世居藏族和移居汉族青少年运动状态下心肺功能的对比研究。结果显示：３４１７ｍ和４２８０ｍ世居藏族的最大氧耗量、无氧阈值及最大心输出量都明显大于汉族,血氧饱和度（Ｓａｏ２）随运动负荷的增加而降低。海拔３４１７ｍ藏、汉族的△Ｓａｏ２分别为７．４６％和１０．０３％,４２８０ｍ处为８．５７％和１３．７５％,最大心率随海拔升高而下降。研究提示,藏族青少年有较高的最大有氧能力,反映了他们对低氧环境的适应优势。     

Comparative electron microscope study of pellicular structures in coccidia (Sarcocystis, besnoitia and Eimeria)

D'Haese J., Mehlhorn H. and Peters W. 1977. Comparative electron microscope study of pellicular structures in coccidia (Sarcocystis, Besnoitia and Eimeria). International Journal for Parasitology7: 505–518. Negatively stained zoites of Sarcocystis ovifelis (= S. tenella pro parte) and Besnoitia jellisoni and sporozoites of Eimeria falciformis were studied by means of electron microscopy and compared with results obtained by other techniques. A new concept for the pellicle of motile coccidia was achieved, which throws some light on the mechanism of motility of these parasites,     

Electron microscopic studies of the development of kinetes in Theileria annulata Dschunkowsky & Luhs, 1904 (Sporozoa, Piroplasmea).

Gamogony of Theileria annulata Dschunkowsky & Luhs occurs within the intestine of nymphs of the tick Hyalomma anatolicum excavatum Koch. After the 5th day post repletionem (p.r.) of the ticks spherical and ovoid parasites were found within the intestinal cells. These stages were thought to represent fertilized macrogametes. These underwent a transformation process leading ultimately to the differentiation of a motile stage, the kinete, which leaves the intestinal cells on the 14th-17th day p.r. and penetrates the alveoles of the salivary glands. The transformation of the stationary into a motile stage takes place by formation of a growing protrusion (= anlage) into an inner, enlarging vacuole. During this process the limiting membrane of the vacuole serves as the outer membrane of the developing motile stage, whereas the 2 inner membranes of its pellicle are newly formed. The steps of this differentiation in T. annulata are compared to the process of ookinete formation in haemosporina.     

Factors restricting diffusion of water-soluble spin labels.

Line broadening of spin label signals is treated in terms of concentration, viscosity, charge and temperature dependencies. Line broadening of spin label signals may be caused either by spin label interactions or by the interaction between a spin label and a second paramagnetic species. Line broadening has been related to collision frequency in the literature and is treated in that way here. Collision frequency is related to diffusion processes in a way that allows information to be obtained about the diffusion environment. Several potential spin label line-broadening agents are compared as to their effectiveness. Small polymer beads with graduated pore sizes are used to show that collisional broadening has a marked dependence on the long-range structure of the diffusion environment. Application of these results to biological diffusion processes is considered.     

The phylogeny of the ant tribe Formicini (Hymenoptera: Formicidae) with the description of a new genus

Abstract. The holarctic ant tribe Formicini is revised, the new genus Bajcaridris described, and possible phylogenetic relationships are discussed. The subgenus Iberoformica is synonymized with Formica. A synopsis, diagnosis and keys to the genera are provided.