One-dimensional collective excitations in Ag atomic wires grown on Si(557).

The interaction between adsorbate layers of transition metal atoms and strongly anisotropic surfaces can lead to various quasi-one-dimensional (1D) signatures, as demonstrated here for Ag adsorbed on Si(557). Using low energy electron diffraction in combination with scanning tunneling microscopy and electron energy loss spectroscopy, we correlated the structure with the properties of low dimensional collective excitations. Semiconducting structures with double periodicity along the chains are formed at Ag coverages below 0.

Effects of tebuconazole on morphology, structure, cell wall components and trichothecene production of Fusarium culmorum in vitro.

The effects of tebuconazole, a systemic fungicide, on the morphology, structure, cell wall components and toxin production of Fusarium culmorum were investigated in vitro. Treatment was by application of four filter paper strips (0.75 cm x 5.

A precursor protein partly translocated into yeast mitochondria is bound to a 70 kd mitochondrial stress protein.

We have probed the environment of a precursor protein stuck in mitochondrial import sites using cleavable bifunctional crosslinking reagents. The stuck precursor was crosslinked to a 70 kd protein which, by immunological techniques, was shown to be a matrix protein. The protein was purified to homogeneity by ATP-Sepharose chromatography and partially sequenced.

Protein translocation across the endoplasmic reticulum membrane: identification by photocross-linking of a 39-kD integral membrane glycoprotein as part of a putative translocation tunnel.

The molecular environment of secretory proteins during translocation across the ER membrane was examined by photocross-linking. Nascent preprolactin chains of various lengths, synthesized by in vitro translation of truncated messenger RNAs in the presence of N epsilon-(5-azido-2-nitrobenzoyl)-Lys-tRNA, signal recognition particle, and microsomal membranes, were used to position photoreactive probes at various locations within the membrane. Upon photolysis, each nascent chain species was cross-linked to an integral membrane glycoprotein with a deduced mass of 39 kD (mp39) via photoreactive lysines located in either the signal sequence or the mature prolactin sequence.

Ca2+-dependent structural changes in bovine blood coagulation factor Va and its subunits.

The calcium dependence of the structures of bovine blood coagulation factor Va and its subunits (Vh and Vl) has been examined spectroscopically in order to characterize the conformational changes which accompany the binding of Ca2+ to Vh and Vl to form factor Va. The far-UV CD spectra of the isolated subunits indicate that the secondary structures of both Vh and Vl are predominantly beta-sheet (greater than 45%), with little alpha-helix content (less than 15%). No change in the far-UV CD spectrum was observed when factor Va was formed by the addition of Ca2+ to an equimolar mixture of Vl and Vh.

Bacteriological findings after premature rupture of the membranes.

Of 243 children born after premature rupture of the membranes (PROM) 61 (26%) had the same bacteria in placental arterial blood, in ear swabs (taken deep from the external auditory canal) and in meconium. The predominant organisms were E. coli, Bacteroides fragilis, Streptococcus faecalis (enterococci) and Streptococcus agalactiae (group B streptococci).

Interaction of blood coagulation factor Va with phospholipid vesicles examined by using lipophilic photoreagents.

Two different lipophilic photoreagents, [3H]adamantane diazirine and 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine (TID), have been utilized to examine the interactions of blood coagulation factor Va with calcium, prothrombin, factor Xa, and, in particular, phospholipid vesicles. With each of these structurally dissimilar reagents, the extent of photolabeling of factor Va was greater when the protein was bound to a membrane surface than when it was free in solution. Specifically, the covalent photoreaction with Vl, the smaller subunit of factor Va, was 2-fold higher in the presence of phosphatidylcholine/phosphatidylserine (PC/PS, 3:1) vesicles, to which factor Va binds, than in the presence of 100% PC vesicles, to which the protein does not bind.

Photocrosslinking of the signal sequence of nascent preprolactin to the 54-kilodalton polypeptide of the signal recognition particle.

Photoreactive moieties were incorporated into nascent polypeptides in a wheat germ protein-synthesizing system by using a plasmid-derived preprolactin mRNA and a Lys-tRNA analog, N epsilon-(5-azido-2-nitrobenzoyl)-Lys-tRNA (epsilon ANB-Lys-tRNA). The presence of the abnormally large amino acid side chains in the nascent chains did not impair function: complete preprolactin chains were synthesized in the absence of the signal recognition particle (SRP), elongation was arrested in the presence of SRP, and SRP-dependent translocation across the membrane of the endoplasmic reticulum and signal peptidase cleavage were observed in the presence of salt-extracted microsomes. Photolysis of elongation-arrested ribosomes resulted in several light- and epsilon ANB-Lys-tRNA-dependent crosslinks.

[Results obtained from staining lymphography, using carbon with lipoidal suspension, in cases of female genital carcinoma (author's transl)].

Reported in this paper is the use of a carbon-lipoidal suspension for presurgical staining lymphography which was applied to carcinomata colli uteri and corporis uteri. The suspension could not be prepared until permission had been obtained from the National Drug Expert Committee. Better colour contrast representation of the femoral and iliacal lymph nodes during the operation was thus achieved, and, consequently, surgical radicality was substantively improved.