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891.
Mike J.M. van der Meer C.G.J. Sweep Gerard J. Pesman Fred J.H. Tilders Ad R.M.M. Hermus 《Cytokine》1996,8(12):910-919
The authors have studied mechanisms which could be involved in the sustained activation of the hypothalamus–pituitary–adrenal (HPA) axis during continuous infusion of rats with recombinant human interleukin-1β (IL-1β). First, the effects of 3 days of intracerebroventricular (i.c.v.) infusion of rats with IL-1 on plasma adrenocorticotropin (ACTH) and corticosterone (B) levels were investigated. Thereafter, changes in plasma ACTH and B levels were followed in rats intraperitoneally (i.p.) infused with IL-1β after immunoneutralization of corticotropin-releasing hormone (CRH), hypophysectomy (HPX), macrophage depletion using dichloromethylene diphosphonate (Cl2MDP)-containing liposomes, adrenalectomy (ADX) and dexamethasone (DEX) administration, respectively. Infusion of IL-1β i.c.v., even in doses as low as 0.1 μg/day, induced significant increases in plasma ACTH and B levels. HPX and ADX rats died within 18 h after starting the IL-1β infusion (0.5 μg/day). Immunoneutralization of CRH significantly decreased and macrophage depletion significantly increased the stimulation of the HPA axis by IL-1 (4.0 μg/day). Administration of high doses of DEX completely abolished the stimulation of the HPA axis by IL-1β (2.0 μg/day). The present study demonstrates that lower doses of IL-1β were able to activate the HPA axis when infused i.c.v. compared with i.p. Regarding stimulation of the HPA axis by chronic i.p. infusion of IL-1β the present study: (1) provides evidence that the CRH system is involved; (2) provides no evidence for a direct stimulatory effect of IL-1β on the release of B by the adrenal gland which is of sufficient magnitude to resist the stress of chronic i.p. IL-1β infusion; (3) shows that endogenous macrophage-derived mediators, induced by i.p. IL-1β infusion, express an overall inhibitory rather than a stimulatory effect on the activity of the HPA axis; (4) demonstrates that exogenous administration of DEX blocks the effect of IL-1β, which fits well in the concept of an immunoregulatory feedback between IL-1β and glucocorticoids. 相似文献
892.
Houfková Petra Horák Jan Pokorná Adéla Bešta Tomáš Pravcová Ivana Novák Jan Klír Tomáš 《Vegetation History and Archaeobotany》2019,28(6):607-621
Vegetation History and Archaeobotany - Medieval vegetation–human–climate interactions were studied from a sediment profile situated in the centre of a short-lived medieval village... 相似文献
893.
894.
M. A. J. Weterman Monique Wilbrink Trijnie Dijkhuizen Eva van den Berg Ad Geurts van Kessel 《Human genetics》1996,98(1):16-21
A combination of Southern blot analysis on a panel of tumor-derived somatic cell hybrids and fluorescence in situ hybridization
(FISH) techniques was used to map a series of DNA markers relative to the 1q21 breakpoint of the renal cell carcinoma (RCC)-associated
(X;1)(p11;q21) translocation. This breakpoint maps between several members of the S100 family which are clustered in the 1q21
region and a conserved region between man and mouse containing the markers SPTA1-CRP-APCS-FcER1A-ATP1A2-APOA2. The location
of the breakpoint coincides with the transition of a region of synteny of human chromosome 1 with mouse chromosomes 3 and
1.
Received: 10 November 1995 / Revised: 3 February 1996 相似文献
895.
Torulopsis ethanolitolerans subject to both the sparing and coarse heat treatment were studied in the scanning electron microscope. The reduction of
adhesivity, increased permeability and higher rigidity of the yeast wall was achieved by an original glutaraldehyde—paraformaldehyde
fixation, low osmolarity in vacuo and subsequent thiosemicarbohydrazide incubation, followed by addition of metal salt. The
impregnation of the metal throughout the specimen due to the reaction of the thiosemicarbohydrazide with glutaraldehyde allowed
viewing of small or intricate surface details of the yeast. Structural differences of the yeast processed by sparing and coarse
heat treatment were shown to be better from the thiosemicarbohydrazide incubated samples compared to those that were prepared
with osmium tetroxide. 相似文献
896.
Daniel Williamson Ian J. McLennan Ad Bax Michael P. Gamcsik Jerry D. Glickson 《Journal of biomolecular structure & dynamics》2013,31(2):375-398
Abstract Two-dimensional NMR experiments-one bond 1H- 13C correlation spectroscopy and hetero- nuclear multiple bond correlation spectroscopy, both performed in the reverse detection mode-have been employed to unambiguously assign all of the 13C resonances of the antibiotic bleomycin and its zinc(II) complex. Previous 1H resonance assignments of bleomycin (Chen et al. (1977) Biochemistry 16, 2731–2738) were confirmed on the basis of homonuclear Hartmann-Hahn and homonuclear COSY experiments. The 13C assignments differ substantially from those previously obtained by other investigators (Naganawa et al., (1977) J. Antibiot. 30, 388–396; Dabrowiak et al., (1978) Biochemistry 17, 4090–4096) but are in agreement with those reported by Akkerman et al.(1988) (Magn. Reson. Chem. 26, 793–802). The more recent study employed similar two-dimensional correlation experiments (performed in the direct detection mode) in conjunction with attached proton tests. Their study often required model compound data to identify carbonyls adjacent to aliphatic moieties. Previous 13C NMR studies of the structure, pH titration, and molecular dynamics of bleomycin and its zinc complex have been reinterpreted in terms of the revised assignments. 相似文献
897.
Application of PE‐RADSeq to the study of genomic diversity and divergence of two Brazilian marmoset species (Callithrix jacchus and C. penicillata) 下载免费PDF全文
898.
Regional genetic diversity patterns in Antarctic hairgrass (Deschampsia antarctica Desv.) 总被引:1,自引:0,他引:1
Aim To determine patterns in diversity of a major Antarctic plant species, including relationships of Antarctic populations with those outside the Antarctic zone.
Location Antarctic Peninsula, Maritime Antarctica, sub-Antarctic islands, Falkland Islands and South America.
Methods Amplified fragment length polymorphisms (AFLPs) and chloroplast sequences were used to study patterns of genetic diversity in Antarctic hairgrass ( Deschampsia antarctica Desv.) and the genetic relationships between populations over its distribution range. Thirty-eight populations were sampled from a large part of the distribution of D. antarctica , and additionally, herbarium specimens were included for areas from which we could not obtain fresh samples.
Results A gradient in AFLP diversity was observed going from the Falklands southwards into the Antarctic. This gradient in diversity was also observed within the Antarctic Peninsula: diversity was lower further south. Diversity in the chloroplast genome of D. antarctica was low. Only three chloroplast haplotypes were found, each with a strong regional distribution.
Main conclusions The phylogenetic construction of AFLP marker frequencies in meta-populations of D. antarctica supports a stepping-stone model of colonization, whereby gene flow mainly occurs between neighbouring populations. It is concluded that long-distance gene flow is very limited in D. antarctica . A very low diversity was found in the sub-Antarctic islands in the Indian Ocean, indicating that these populations have experienced a recent evolutionary bottleneck. 相似文献
Location Antarctic Peninsula, Maritime Antarctica, sub-Antarctic islands, Falkland Islands and South America.
Methods Amplified fragment length polymorphisms (AFLPs) and chloroplast sequences were used to study patterns of genetic diversity in Antarctic hairgrass ( Deschampsia antarctica Desv.) and the genetic relationships between populations over its distribution range. Thirty-eight populations were sampled from a large part of the distribution of D. antarctica , and additionally, herbarium specimens were included for areas from which we could not obtain fresh samples.
Results A gradient in AFLP diversity was observed going from the Falklands southwards into the Antarctic. This gradient in diversity was also observed within the Antarctic Peninsula: diversity was lower further south. Diversity in the chloroplast genome of D. antarctica was low. Only three chloroplast haplotypes were found, each with a strong regional distribution.
Main conclusions The phylogenetic construction of AFLP marker frequencies in meta-populations of D. antarctica supports a stepping-stone model of colonization, whereby gene flow mainly occurs between neighbouring populations. It is concluded that long-distance gene flow is very limited in D. antarctica . A very low diversity was found in the sub-Antarctic islands in the Indian Ocean, indicating that these populations have experienced a recent evolutionary bottleneck. 相似文献
899.
900.
Lycotoxin I and Lycotoxin II are natural anti-microbial peptides that were identified in the venom of the Wolf Spider Lycosa carolinensis. These peptides were found to be potent growth inhibitors for bacteria (Escherichia coli) and yeast (Candida glabrata) at micromolar concentrations. Recently, shortened analogues of LycoI and LycoII have been reported to have decreased haemolytic effects. A shorter Lyco-I analogue studied, LycoI 1-15 (H-IWLTALKFLGKHAAK-NH2), was active only above 10 microM, but was also the least haemolytic. On the basis of these findings, we became interested in obtaining a deeper insight into the membrane activity of LycoI 1-15, as this peptide may represent the first major step for the future development of selective, i.e. non-haemolytic, Lycotoxin-based antibiotics. The interaction of this peptide with liposomes of different composition was studied by microcalorimetry [differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC)] and CD. The results obtained from the calorimetric and spectroscopic techniques were jointly discussed in an attempt to further understand the interaction of this peptide with model membranes. 相似文献