The behaviour of male orchid bees (Apidae,Hymenoptera, Insecta) and the question of leks

The male territories of two species of orchid bees, Eulaema meriana and Euglossa imperialis, are described. These territories consist of a perch, where the males display on the trunk of a tree, and a route flown from and back to the perch. Territories are located in treefalls or other large light gaps in tropical forest. The territories of these two species differ in the height of the perch and amount of light reaching it, size of the perch tree, and period of activity. A definition of lek is given. These male euglossines form facultative leks in large treefalls. The relationships between male territories, female foraging ranges, and collection of aromatic material by males are discussed.     

Differences in domain structure between human fibronectins isolated from plasma and from culture supernatants of normal and transformed fibroblasts. Studies with domain-specific antibodies

The domain structure of human fibronectins isolated from plasma and from the conditioned medium of normal and transformed fibroblasts was analyzed by limited proteolysis and S-cyanylation followed by immunostaining of released fragments with five kinds of antibodies, each specific for one functional domain. The results indicate that all three human fibronectins are composed of the same set of functional domains aligned in the same topological order. However, the following clear differences were found in specific fragments released from plasma fibronectin (pFN) and those released from fibronectin of normal (N-cFN) and transformed fibroblasts (T-cFN). Two fragments (Mr = 70,000 and 60,000) were released from the COOH-terminal region of pFN by cathepsin D. These fragments represent the COOH-terminal heparin-binding (Hep-2) and fibrin-binding (Fib-2) domains. The corresponding fragments released from both N-cFN and T-cFN by cathepsin D had much larger molecular weights (Mr = 100,000 and 83,000-74,000) than those from pFN. The fragments from the Fib-2 domain alone, however, did not show any difference among all three FNs. The internal region, from the gelatin-binding (Gel) domain through the Hep-2 domain, of N-cFN and T-cFN was released as a Mr = 210,000 fragment upon mild trypsin digestion. The corresponding fragment from pFN was released as a Mr = 185,000 fragment. The COOH-terminal half, including the Hep-2 domain, of both N-cFN and T-cFN was released by S-cyanylation as Mr = 160,000-145,000 fragments, which are 25,000-20,000 larger than the corresponding fragments of pFN. These results clearly indicate that the Hep-2 domain of N-cFN and T-cFN is 30,000-20,000 daltons larger than the same domain of pFN. Although various fragments released from N-cFN and T-cFN showed a similar pattern, there were minor differences. Thermolysin fragments derived from the Hep-2 domain of N-cFN were clearly distinguishable from those from T-cFN. Three groups of fragments with Mr = 40,000, 35,000-32,000, and 30,000 were released from N-cFN, while only the 35,000-32,000 fragment was released from T-cFN. The Mr = 44,000/60,000 thermolysin fragments representing the Gel domain and the Mr = 210,000/165,000 tryptic fragments representing the internal domains of T-cFN were slightly, but consistently, larger than those of N-cFN.(ABSTRACT TRUNCATED AT 400 WORDS)     

Demonstration of structural differences between the two subunits of human-plasma fibronectin in the carboxy-terminal heparin-binding domain

Structural differences between the two subunits of human plasma fibronectin were studied by analyzing the carboxy-terminal heparin-binding domain (Hep-2). Two fragments (29 kDa and 38 kDa) derived from the Hep-2 domain were purified from thermolysin-digested human plasma fibronectin. Identical NH2-terminal sequences were obtained for both fragments through 16 Edman cycles. Neither domain contained the 90-amino-acid extra domain which is predicted by cDNA analysis of the cellular form of fibronectin. We have examined the primary structures of the 29-kDa and 38-kDa Hep-2 domains produced from the two chains of plasma fibronectin by analyzing the tryptic peptides by fast atom bombardment/mass spectrometry and comparison with the predicted fragments deduced from the corresponding cDNA-derived peptide sequences. Peptides that were unique to each domain were further characterized by microsequence analysis. The two domains showed identical amino acid sequences through 274 residues, followed by a region of variability. The 29-kDa domain contains 279 amino acids with an estimated relative molecular mass (Mr) of 30,460. This domain is located in the heavy chain of plasma fibronectin and contains three repeats of type III sequences plus a portion of the connecting segment (IIICS) region. The 38-kDa domain contains 359 amino acids and one O-linked glycosyl unit for an estimated Mr of 39,263. This domain is from the light chain of plasma fibronectin and contains four repeats of type III sequences with the deletion of the entire 120-amino-acid IIICS area. Secondary structure analysis by Chou/Fasman and circular dichroism reveals extensive beta-sheet structure for these domains. Key sulfhydryl and glycosylation sites are located near the mRNA splice junctions for the two chains. It is postulated that the splice junctions are adjacent to a flexible domain joining two regions of extensive beta-sheet structure.     

Genetic diversity in a germplasm collection of roseroot (Rhodiola rosea) in Norway studied by AFLP

Rhodiola rosea is widely distributed in Norway, but so far limited knowledge exists on the level of genetic diversity. To initiate a selective breeding program, Amplified Fragment Length Polymorphism (AFLP) analysis was used to estimate genetic diversity within the Norwegian R. rosea germplasm collection. AFLP analysis of 97 R. rosea clones using five primer combinations gave a total of 109 polymorphic bands. We detected high percentage of polymorphic bands (PPB) with a mean of 82.3% among the clones of R. rosea. Each of the 97 R. rosea clones could be unambiguously identified based on these primer combinations. Estimates of genetic similarities were obtained by the Dice coefficient, and a final dendrogram was constructed with the Unweighted Pair Group Method with Arithmetic mean (UPGMA). Genetic similarity based on the AFLP data ranged from 0.440 to 0.950 with a mean of 0.631. This genetic analysis showed that there was no close genetic similarity among clones related to their original growing county. No gender-specific markers were found in the R. rosea clones. Analysis of molecular variance (AMOVA) revealed a significantly greater variation within regions (92.03%) than among regions (7.97%). A low level of genetic differentiation (F_ST = 0.043) was observed, indicating a high level of gene flow, which had a strong influence on the genetic structure at different counties. Our results indicate high gene flow among R. rosea clones that might be a result of seed dispersal rather than cross-pollination. Further world-wide studies are required to compare the level of genetic diversity and more studies in R. rosea detailing the consequences of different patterns of gene flow (pollen spread and dispersal of seeds and clonal plants) will be useful for characterization of roseroot.     

Differences in drifting of larval stages of Rhyacophila nubila (Trichoptera)

Larval drift of the trichopteran Rhyacophila nubila (Zett.) was studied in a West Norwegian river. The frequency distribution of different instars in the drift samples was significantly different compared with the benthic samples. The drift, measured as the number which passed a transect of the river, rised markedly in periods of high water discharge. Different instars can be arranged according to the extent in which they are drifting: 2>3>4>1>5. Instar 1 and 2 shared a neutral phototaxis. From the 2nd instar and on, the larvae became increasingly night-active with a culmination in the last instar which was highly night active, also confined by laboratory studies. It is suggested that changes in activity patterns is associated with a shift towards a more carnivorous way of life.     

Favorable Alteration of Tumor Microenvironment by Immunomodulatory Cytokines for Efficient T-Cell Therapy in Solid Tumors

Unfavorable ratios between the number and activation status of effector and suppressor immune cells infiltrating the tumor contribute to resistance of solid tumors to T-cell based therapies. Here, we studied the capacity of FDA and EMA approved recombinant cytokines to manipulate this balance in favor of efficient anti-tumor responses in B16.OVA melanoma bearing C57BL/6 mice. Intratumoral administration of IFN-α2, IFN-γ, TNF-α, and IL-2 significantly enhanced the anti-tumor effect of ovalbumin-specific CD8+ T-cell (OT-I) therapy, whereas GM-CSF increased tumor growth in association with an increase in immunosuppressive cell populations. None of the cytokines augmented tumor trafficking of OT-I cells significantly, but injections of IFN-α2, IFN-γ and IL-2 increased intratumoral cytokine secretion and recruitment of endogenous immune cells capable of stimulating T-cells, such as natural killer and maturated CD11c+ antigen-presenting cells. Moreover, IFN-α2 and IL-2 increased the levels of activated tumor-infiltrating CD8+ T-cells concomitant with reduction in the CD8+ T-cell expression of anergy markers CTLA-4 and PD-1. In conclusion, intratumoral administration of IFN-α2, IFN-γ and IL-2 can lead to immune sensitization of the established tumor, whereas GM-CSF may contribute to tumor-associated immunosuppression. The results described here provide rationale for including local administration of immunostimulatory cytokines into T-cell therapy regimens. One appealing embodiment of this would be vectored delivery which could be advantageous over direct injection of recombinant molecules with regard to efficacy, cost, persistence and convenience.     

Ovarian function and pregnancy rates in reindeer calves (Rangifer tarandus ) in Southern Norway

Reindeer calves (n = 632) were slaughtered in November/December (n = 476) or in January (n = 156). Dressed weights and amount of perirenal fat were recorded, and the reproductive organs were collected. A separate group of 130 reindeer calves were weighed at 7 months of age and were followed up with repeated weighings and pregnancy examinations up to 21 months. The onset of puberty and the pregnancy rate were significantly influenced by body weight and the amount of perirenal fat. Approximately 60 g of perirenal fat and 22 kg dressed weight were found at the lower limits for pregnancy. A total of 222 (35%) animals had reached puberty and 126 (20%) were pregnant when examined after slaughter. Animals which conceived during their first autumn showed only a moderate weight gain the following year, and the calf mortality rate in these animals was 47.4%. It was concluded that calf pregnancies are common among the reindeer of Southern Norway and that measures need to be taken to prevent them.