THE BEHAVIOUR OF THE WILLOW WARBLER PHYLLOSCOPUS TROCHILUS IN CONTINUOUS DAYLIGHT

Willow Warblers Phylloscopus trochilus at Wytham, Oxford (51° 46' N., 1° 15' W.), start to sing around sunrise, in late April to early June. In the continuous daylight at Neiden, East Finnmark (69° 42' N., 29° 25' E.), they do not sing all the time, but in late June to late July start singing between 22.45 and 01.45 hrs., the start becoming progressively later as the season draws on. At Neiden, nest visits start some time after song (01.00–02.30), and this is probably also true at Wytham.
The influence of environmental variables on the starts of the two cycles is discussed. It is concluded that song starts at Wytham when light intensity has risen above a certain threshold level, and at Neiden, when it has reached a minimum value or has started to rise again. It is suggested that the Neiden birds react to the closest approximation of their light intensity cycle to that at dawn further south. The end of daily song at Neiden may be controlled by internal factors. It is suggested that the start of the Neiden nest-visit cycle is controlled by light intensity, but modified by temperature effects. The possibility that the environment affects the bird indirectly, via its brood or food, can be ruled out. The functional significance of the retention of activity lulls in the continuous daylight of the Arctic summer is discussed.
The daily song-starts of the Garden Warbler Sylvia borin , Brambling Fringilla montifringilla , and Yellowhammer Emberiza citrinella , follow the same pattern as those of the Willow Warbler. The Redwing Turdus musicus often has no daily song lull; its nest-visit lull begins and ends well before midnight. The significance of this is discussed.     

海洋抗肿瘤活性大环内酯类化合物化学成分研究近况

最近,人们已从多种海洋生物中发现许多具有应用价值的生理活性物质。其中,抗肿瘤活性物质的开发研究尤为盛行。目前,人们已经分离得到许多在体内试验中具有明显抗肿瘤活性的化合物,并且确立了它们的化学结构,其中包括类萜类化合物、生物碱,肽类化合物、大环内酯类化合物、类前列腺素化合物、聚醚类化合物等。其中,已有数种大环内酯类化合物很有可能作为抗癌药物进入临床。bryostatin 1则是它们的代表性化合物之一。目前,美国National Cancer Instituie已经开始对该化合物进行临床研究。它是由作者(釜野)研究小组在美国亚利桑拿州立大学癌研究所开发研究出的一种新型化合物,经过进一步研究又分离得到了bryostatin 2(24)～13(35),并确立了它们的化学结构。因此,本文将对bryostatin类化合物的化学性质以及其生理活性作详细地综述。另外,还将论述halichondrin类化合物(14～21)和Aplyronine(22)。它们是最近几年在日本发现的,在体内试验中具有很强的抗肿瘤活性的一系列新型化合物。再者,本文还将概述其它一些重要的、具有抗肿瘤活性的大环内酯类化合物,即aplysiatoxin(Ia～Ic), latrunculinA(2), acutiphycin(3),tedanolide(4), swinholide A(5), bistheonellde A(7a), amphicinolides(8～10), kabiramides(11a 11e), ulapualide(12a, 12b)以及patellazole B(13)。