Topographic anatomical data on the a.testicularis, a.ductus deferentis and a.cremasterica in ram

130 Ram testes have been used in the study, and the following methods were applied to fill and study the testical arteries: r?ntgenography, stereor?ntgenography, corosive method, Indian ink and gel injections. Variabilities occur as to the site where the a.testicularis arises in rams. Individual differences can also be observed in the arrangement of the epididymal arteries, in most cases, however, they arise from the first loops of the convolution. Both epididymal arteries are considerably thinner than the testicular artery, forming 2 independent vessel convolutions, located at both sides of the convolution of the a.testicularis, and not interfering with the loops of the latter. A.accessoria testis has been found in one ram only. 2 to 3 large waved loops can be observed in the pars marginalis and the a.testicularis of the ram. Bifurcation mostly occurs in the second third of the margo epididymidis. Individual variations have been found at further ramification of the rr.testiculares. The shape of the lobulus testis is indicated by the centripetal branch with its centrifugal twigs. In rams the a.ductus deferentis forms anastomoses both with the branches running from the a.epididymidis caudalis and the a.cremasterica.     

Phenol-treatment and a homologous pairing-assay.

Homologous pairing is a key step in homologous genetic recombination. In the early stage of trials for the identification of homologous pairing-promoting proteins from a fission yeast, Schizosaccharomyces pombe, we treated DNA products with phenol in the presence of a salt for the removal of tightly bound proteins from DNA before the assay, but we found that this treatment caused very efficient protein-independent double-strand formation from complementary single-stranded DNAs. Using an assay including the phenol treatment, we detected another species of apparent homologous pairing-promoting proteins in the nuclei, in addition to a homologous pairing-promoting protein consisting of three components which we reported previously. However, studies involving the use of an assay without the phenol-treatments revealed that the second one was not really a homologous pairing-protein. Thus, the protein-independent double-strand formation by phenol-treatment in the presence of a salt could cause the erroneous identification of homologous pairing-promoting proteins.     

Acholeplasma multilocale sp. nov., isolated from a horse and a rabbit.

Acholeplasma strains were isolated from the nasopharynx of a horse (strain PN525T [T = type strain]) and the feces of a rabbit (strain B1). One clone of strain PN525T and one clone of strain B1 were examined in detail. These clones were indistinguishable from each other and were serologically distinct from the previously described Acholeplasma and Mycoplasma spp. The strains had the following properties: guanine-plus-cytosine content of 31 mol%; sterol was not required for growth, which occurred under both aerobic and anaerobic conditions; glucose was metabolized; and arginine was hydrolyzed. Strain PN525 (= NCTC 11723) is the type strain of a new species, Acholeplasma multilocale.     

Transpeptidation in sequence analysis. Investigations concerning a native and a synthetic hexapeptide.

On sequencing a hemoglobin a peptic hexapeptide with the amino acid composition Asp2, Gly, Val, Lys2 was isolated. Cleavage of this peptide with Tos-Phe-CH2Cl-trypsin resulted in the fragments Asp-Lys, Gly-Asp, Val-Lys, Asp--Lys-Gly-Asp, Asp-Lys-Val-Lys and Val-Lys-Gly--Asp. From these data two possible but inconsistent sequences for the hexapeptide can be derived: Asp-Lys-Val-Lys-Gly-Asp and Val-Lys-Asp-Lys-Gly-Asp. Fragments obtained by other cleavage procedures, direct sequencing of the globin peptide-chain with a sequenator as well as X-ray data of this hemoglobin show, that only the sequence starting with Asp occurs in the intact protein. Therefore the peptide Asp-Lys-Gly-Asp must have been formed by transpeptidation during sequence work. In order to verify this, Asp-Lys-Val-Lys-Gly-Asp was synthesized by an unequivocal, conventional procedure. Tryptic digestion of this hexapeptide also resulted in ASP-Lys-Gly-Asp in addition to the expected fragments. Thus it has been shown for the first time, that sequencing conditions may alter the constitution of a peptide.