837 research outputs found
Both recombinant African catfish LH and FSH are able to activate the African catfish FSH receptor
LH and FSH are heterodimeric glycoprotein hormones, composed of a common alpha-subunit non-covalently associated with a hormone-specific beta-subunit. Repeated efforts to isolate catfish FSH (cfFSH) have not been successful and only catfish LH (cfLH) has been purified from catfish pituitaries. Recently, however, we succeeded in cloning the cDNA encoding the putative cfFSHbeta; the cDNAs for the alpha- and beta-subunit of cfLH have been cloned before. Here we report the expression of biologically active cfLH and cfFSH in the soil amoeba, Dictyostelium discoideum. The biological activity of the recombinant hormones was analyzed using cell lines transiently expressing either the cfLH receptor or the cfFSH receptor. Moreover, a primary testis tissue culture system served to study the steroidogenic potency of the recombinant hormones. Our results demonstrated that Dictyostelium produced biologically active, recombinant catfish gonadotropins, with recombinant cfLH being almost indistinguishable from its native counterpart, purified from pituitaries. Although recombinant cfFSH has significant effects in the bioassays used in this study, the specific function of native cfFSH in the control of reproduction and its expression patterns are not yet understood
The far carboxy-terminus of the viral encoded chemokine receptor US28 binds to the sorting protein GASP-1 in vitro
Properties of Exotic Matter for Heavy Ion Searches
We examine the properties of both forms of strange matter, small lumps of
strange quark matter (strangelets) and of strange hadronic matter (Metastable
Exotic Multihypernuclear Objects: MEMOs) and their relevance for present and
future heavy ion searches. The strong and weak decays are discussed separately
to distinguish between long-lived and short-lived candidates where the former
ones are detectable in present heavy ion experiments while the latter ones in
future heavy ion experiments, respectively. We find some long-lived strangelet
candidates which are highly negatively charged with a mass to charge ratio like
a anti deuteron (M/Z=-2) but masses of A=10 to 16. We predict also many
short-lived candidates, both in quark and in hadronic form, which can be highly
charged. Purely hyperonic nuclei are bound and have a negative charge while
carrying a positive baryon number. We demonstrate also that multiply charmed
exotics (charmlets) might be bound and can be produced at future heavy ion
colliders.Comment: 10 pages, 4 figures, uses IOP style and epsf.sty, to be published in
Journal of Physics, Proceedings of the International Symposium on Strangeness
in Quark Matter 1997, April 14-18, Thera (Santorini), Hellas. Corrected
typos, added comment about bag constant
Many--Particle Correlations in Relativistic Nuclear Collisions
Many--particle correlations due to Bose-Einstein interference are studied in
ultrarelativistic heavy--ion collisions. We calculate the higher order
correlation functions from the 2--particle correlation function by assuming
that the source is emitting particles incoherently. In particular
parametrizations of and relations between longitudinal, sidewards, outwards and
invariant radii and corresponding momenta are discussed. The results are
especially useful in low statistics measurements of higher order correlation
functions. We evaluate the three--pion correlation function recently measured
by NA44 and predict the 2--pion--2--kaon correlation function. Finally, many
particle Coulomb corrections are discussed.Comment: 5 corrected misprints, 14 pages, revtex, epsfig, 6 figures included,
manuscript also available at http://www.nbi.dk/~vischer/publications.htm
Organization and dynamics of the SpoVAEa protein and its surrounding inner membrane lipids, upon germination of <i>Bacillus</i> <i>subtilis</i> spores
The SpoVA proteins make up a channel in the inner membrane (IM) of Bacillus subtilis spores. This channel responds to signals from activated germinant receptors (GRs), and allows release of Ca(2+)-DPA from the spore core during germination. In the current work, we studied the location and dynamics of SpoVAEa in dormant spores. Notably, the SpoVAEa-SGFP2 proteins were present in a single spot in spores, similar to the IM complex formed by all GRs termed the germinosome. However, while the GRs’ spot remains in one location, the SpoVAEa-SGFP2 spot in the IM moved randomly with high frequency. It seems possible that this movement may be a means of communicating germination signals from the germinosome to the IM SpoVA channel, thus stimulating CaDPA release in germination. The dynamics of the SpoVAEa-SGFP2 and its surrounding IM region as stained by fluorescent dyes were also tracked during spore germination, as the dormant spore IM appeared to have an immobile germination related functional microdomain. This microdomain disappeared around the time of appearance of a germinated spore, and the loss of fluorescence of the IM with fluorescent dyes, as well as the appearance of peak SpoVAEa-SGFP2 fluorescent intensity occurred in parallel. These observed events were highly related to spores’ rapid phase darkening, which is considered as due to rapid Ca(2+)DPA release. We also tested the response of SpoVAEa and the IM to thermal treatments at 40–80 °C. Heat treatment triggered an increase of green autofluorescence, which is speculated to be due to coat protein denaturation, and 80 °C treatments induce the appearance of phase-grey-like spores. These spores presumably have a similar intracellular physical state as the phase grey spores detected in the germination but lack the functional proteins for further germination events
Inhomogeneous Nucleation of Quark-Gluon Plasma in High Energy Nuclear Collisions
We estimate the probability that a hard nucleon-nucleon collision is able to
nucleate a seed of quark--gluon plasma in the surrounding hot and dense
hadronic matter formed during a central collision of two large nuclei at AGS
energies. The probability of producing at least one such seed is on the order
of 1-100\%. We investigate the influence of quark--gluon plasma formation on
the observed multiplicity distribution and find that it may lead to noticable
structure in the form of a bump or shoulder.Comment: 16 pages, latex and 12 ps figures available on reques
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