Heterogeneity ofHLA defined in PLT: A cellular assay detects differences not seen using HLA-DRw serology

The primed lymphocyte typing test (PLT) is used to detect the gene products of theHLA-D region which are responsible for secondary restimulation of cells primed in MLC. Alternatively, products of theHLA-D region may be detected serologically using antisera directed against a subpopulation of lymphocytes; these are the so-called DRw determinants. The PLT was used to see if it were possible to detect heterogeneity within a given serologically defined group using a cellular test. As priming combinations, we used family members identical for one haplotype and differing in theHLA-A, B andC regions, but not theD region of the second haplotype. Our results indicated that it was possible to prime against this second haplotype and that the segregation of the difference followedHLA. Therefore, using a cellular test it was possible to detect differences among cells belonging to a given DRw group. This suggests that PLT can be a useful tool to identify those serological groups which are composed of heterogenous determinants. In addition, it points out the problem in using any one test to establish identity of theHLA-D region, especially for clinical purposes.     

Unusual behaviour of SPO1 DNA with respect to restriction and modification enzymes recognizing the sequence 5''-G-G-C-C

Summary SPO1 DNA contains only 5 cleavage sites for restriction enzymes which recognize and cleave the sequence 5-G-G-C-C (HaeIII or BsuR). Fragments of SPO1 DNA cloned in E. coli to substitute 5-hydroxymethyluracil (HMU) by thymine (T) remain resistant to HaeIII indicating that this unexpectedly small number of cleavages by HaeIII is not correlated with the presence of HMU in the normal phage DNA. It was previously shown that SPO1 is neither subject to B. subtilis R restriction (Trautner et al., 1974) nor modification in vivo (Günthert et al., 1975). We now show that SPO1 DNA can however be restricted and modified in vitro.     

Creatine kinase isoenzyme BB in serum of patients undergoing chronic hemodialysis and with kidney transplant.

The activity of creatine kinase isoenzyme BB (CK-BB) was determined in serum of healthy adults and in patients undergoing maintenance hemodialysis and with kidney transplant. In the healthy adults examined, an activity of 0.56 +/- 0.16 U/l (mean +/- SD) was found. The arithmetic mean of CK-BB activity in patients with renal insufficiency under hemodialysis was 1.42 +/- 0.87 U/l and differed from that of the healthy group. The CK-BB activity in patients with kidney transplant was not different from that of the control group. The occurrence of CK-BB in serum is discussed from diagnostic and methodological point of view.     

Use of gen5 and gen6 ts-mutants of phage T3 as indicators of inhibitors of DNA synthesis]

In an enzyme-specific drug screening system nalidixic acid and 3'-FTdR, inhibitors of DNA synthesis, both reduce the growth of wild type and temperature-sensitive point mutants of phage T3 with different efficiencies. The wild type shows the strongest sensitivity against the drugs, while an exonuclease mutant is the most insensitive variant. The DNA polymerase mutants exhibit an intermediate degree of inhibition. The anthracycline antibiotics violamycin BI and adriblastin which preferentially inhibit RNA synthesis show the same degree of inhibition for all mutants. This is true also for the RNA synthesis inhibitor lambdamycin, which is identical with chartreusin. The protein synthesis inhibitors chloramphenicol and o-phenanthroline, a chelating agent, impair all mutants to the same extent. Our data confirm the hypothesis that structural variants of essential viral enzymes, when compared with the wild type should reveal different sensitivities against specific inhibitors and show that this T3 system could be used for the indication of specific inhibitors of DNA synthesis.     

The role of auditory stimuli in the courtship of Drosophila melanogaster

Simulated courtship song of male Drosophila melanogaster was played to males or females of this species. Upon receiving the song males increase their locomotor activity and start courting each other, whereas females reduce their locomotor activity. In wingless males the locomotor activity difference between the silent control and the experimental sound situation is much larger than in winged males, due to the inactivity of wingless males in the control situation. Males which had been kept singly up to the time of the experiment exhibit higher locomotor and sexual activity than group housed males. A second component of the male courtship song ‘sine song’ is described, together with experiments which investigate the sensory basis of the effect male courtship song has on males.     

The function of pulse song and sine song in the courtship of Drosophila melanogaster

Drosophila melanogaster females were subjected to pulse song before being allowed to mix with males. Sine song increases female receptivity, pulse song does not. Pulse song does however increase receptivity if the females are subjected to it while being courted by males which are deaf and which cannot produce any auditory stimulation themselves. It is suggested that sine song is summated and has a priming effect on female receptivity whereas pulse song functions as a species recognition signal in a trigger-like fashion.