Summer dispersal and survival of juvenile Great Tits in southern Sweden

Summary Movements and survival of 506 first-brood Great Tit nestlings that fledged in mid-June in an oak wood in southern Sweden were studied by intensive trapping in that wood and in several neighbouring woods between 17 July and 10 September 1977. A total of 1177 captures of 508 individuals was made.Two periods of summer dispersal can be distinguished: the first period, one to one- and-one-half months after fledging, lasts longer in females and results in females moving farther away from their birthplace than males; and the second period in early September. There was no effect of brood-size, fledging date or size on dispersal movements. There is, however, a nest effect in that siblings tend to be more alike in the distance moved than non-siblings.The summer mortality rate is constant but high (13% per week). It is not affected by brood size or fledging date, but during the first month after fledging large individuals survive better than smaller ones. The summer mortality rate of dispersers (birds moving between woods) is not higher than that of non-dispersers.The results contradict two hypotheses proposed to explain when and how postfledging mortality occurs. The mortality rate is not higher during the first month after fledging, as Perrins' and Lack's hypothesis predicts. Since only 22% of the young are still alive at the beginning of September, autumn territorial behaviour cannot be the main factor causing juvenile losses, as proposed by Kluyver.There is some circumstantial evidence that Great Tits compete for food during the summer, and that food therefore could be in short supply, as suggested by Perrins.The observed differential dispersal of adults and young, and of male and female juveniles, may be the result of the dominance relationships in the family flock and later in the summer flocks, with subordinate individuals moving farthest.     

Produits neutres et alcaloides de Myrtopsis macrocarpa,M. myrtoidea,M. novae-caledoniae et M. sellingii

Stems and leaves of Myrtopsis macrocarpa, M. myrtoidea, M. novae-caledoniae and M. sellingii yielded terpenes, sterols, coumarins, alkaloids (furoquinolines and quinolones) and amides. A new quinolone (8-methoxy flindersine) occurs in Myrtopsis macrocarpa, a new amide (N-benzoyltryptamine) in M. myrtoidea, two new coumarins (myrsellin and myrsellinol) and a new dihydrofuroquinoline (myrtopsine) in M. sellingii. Structures of the new compounds are proposed from chemical and spectroscopic evidence.     

Xanthones et C-glucosides flavoniques du genre Gentiana (section Cyclostigma)

Xanthones with a uniform 1,3,7,8-oxidation pattern, the C-glycosides isoorientin and isovitexin, and in some cases mangiferin, were isolated from the aerial parts of G. nivalis, G. brachyphylla, G. favrati, G. rostani, G. utriculosa and G. schleicheri Kunz. The distribution of these compounds within the section Cyclostigma is given. Comparison of phenolic patterns in other sections of Gentiana is made.     

NMR characterization of three forms of ferredoxin from Desulphovibrio gigas, a sulphate reducer

A NMR and magnetic susceptibility study of the oxidized and reduced states of three different oligomers (forms) of a [4Fe-4S] ferredoxin protein from Desulphovibrio gigas, FdI, FdI′, and FdII was carried out. FdI and FdI′ are different trimers and FdII a tetramer of the same basic subunit. A probable assignment of the contact shifted resonances is indicated. Since the temperature dependences of the contact shifted resonances associated with each [4Fe-4S] are not all similar a delocalized model for the spin densities on the 4Fe does not apply. The exchange rate between oxidized and reduced states is slow on the NMR time scale. The three oligomers are not magnetically equivalent. Using the “three state hypothesis” terminology it is shown that FdI_ox is predominantly in the C^2? state and changes upon reduction into the C^3? state, while FdII_ox is in the C^? state and changes into the C^2? state. FdI′ does not easily fit into this classification. This study shows a similarity of magnetic behaviour between FdI and bacterial ferredoxins (e.g. Bacillus polymyxa) and between FdII and HiPIP from Chromatium sp.. The influence of the quaternary structure on the stabilization of the different oxidation states of ferredoxins as well as on their redox potentials is discussed.     

Fibroblastlike primary cells from human colon adenocarcinoma explants: Collagen biosynthesis

Summary Fibroblastlike primary cells have been obtained from human colon adenocarcinoma explants. Such cells disappear during cell culture and thus have not been previously studied. These cells have a number of altered phenotypic characteristics: a) morphology; b) growth behavior and adherence to culture substrate (they required 3 h for 90% attachment and only presented a flattened morphology 40 h after platting); and c) collagen metabolism. Increased protein biosynthesis (about double than control colon-derived fibroblasts) and maintained ability for collagen biosynthesis have been observed for the tumor-associated fibroblastlike cells. Thus, the collagen to noncollagenous proteins ratio was decreased for these cells. They exhibited an altered type I:type III collagen (5:1 instead of 3:1 in colon fibroblasts) and procollagen (2:1 against 5:1 in colon fibroblasts) ratios as well as a decreased secretion of collagen with an abnormal deposition of procollagens in the cell layer. These studies show a permanent phenotypic alteration in the tumor-associated fibroblastlike cells.     

Hydrodynamics of Ebrié lagoon as revealed by a chemical and isotopic study

To determine the origin and the circulation of waters in the different areas of the Ebrié lagoon (Ivory Coast), ionic concentrations (K⁺ Cl^-) and isotopic (¹⁸O) measurements were performed. Sixty stations were sampled. Chemical and isotopic analyses were made thrice during a hydrological cycle: in May 1986, at the end of the great dry season; in October 1986, during the maximum of rainfall, in December 1987, after the Comoe river peak flow. From a hydrodynamical point of view, the results reported in this work indicate that the lagoon comprises four distinctive areas. The first is filled with freshwater all the year round and is characterized by an weak isotopic enrichment (these waters are of continental origin and annually renewed); the second corresponds to oligohaline waters highly enriched in¹⁸O (waters essentially of continental origin and poorly renewed); the third area is constituted of a mixture of waters of continental and oceanic origins. The latter group can be separated into two subgroups: a group completely renewed by oceanic water during the dry season and another group totally renewed by freshwater during the rainy and flood seasons.     

Differences in relative growth rate in 11 grasses correlate with differences in chemical composition as determined by pyrolysis mass spectrometry

Summary Eleven grass species varying in potential relative growth rate (RGR) were investigated for differences in chemical composition by pyrolysis mass spectrometry. The spectral data revealed correlations between RGR and the relative composition of several biopolymers. Species with a low potential RGR contained relatively more cell wall material such as lignin, hemicellulose, cellulose, polysaccharide-bound ferulic acid and hydroxyproline-rich protein, whereas species with a high potential RGR showed relatively more cytoplasmic elements such as protein (other than those incorporated in cell walls) and sterols.     

Effect of imazaquin on absorption,translocation, and pattern of distribution of chlormequat chloride in winter wheat

The role of imazaquin in the absorption, translocation, and distribution of chlormequat chloride in CYCOCEL^* CL has been studied in winter wheat. Three treatments were applied to the 5th leaf of the main stem at growth stage 5 (Feekes Large scale): (1)¹⁴C-chlormequat chloride, (2) CYCOCEL^* CL containing¹⁴C-chlormequat chloride, and (3) CYCOCEL^* CL containing¹⁴C-imazaquin. Tracing of the radioactivity was followed in the treated leaf, main stem, tillers, and roots. Results showed that more than 85% of the radioactivity absorbed remained in the treated leaf. Ten days after the application of chlormequat chloride alone, 94.4% of the¹⁴C-chlormequat was found in the treated leaf, 2.9% in the main stem, 1.2% in the tillers, and 1.4% in the root system versus 88.2, 8.2, 2.1, and 1.4%, respectively, for the chlormequat chloride plus imazaquin treatment. It was concluded that imazaquin increases the mobility and the pattern of distribution of chlormequat chloride in the plant.