Comparison of the nucleotide sequence of cloned DNA coding for an apolipoprotein (apoVLDL-II) from avian blood and the amino acid sequence of an egg-yolk protein (apovitellenin I): equivalence of the two sequences

We have compared the amino acid sequences of two low-molecular-weight avian apoproteins: apoVLDL-II from very low-density lipoproteins of hen plasma and apovitellenin I from hen egg yolk. The sequence of White Leghorn apoVLDL-II was derived from the nucleotide sequence of cloned apoVLDL-II DNA (Chan et al., 1980). The sequenator was used to determine the amino acid sequence of apovitellinin I from two breeds of hen (White Leghorn and Australorp). The sequences from the two breeds were not only identical, but they also completely matched the predicted sequence derived from the apoVLDL-II DNA sequence. The identity reported here establishes that this protein is transported intact from the blood to the egg yolk.     

Responses of the spider Argiope aurantia to low frequency phasic and continuous vibrations

I maintained female orb-weaving spiders, Argiope aurantia, in the laboratory and subjected them to low frequency phasic and continuous transverse vibrations of known frequency, amplitude, and position on the web. Stimuli were administered for periods of 1 min and all behaviour recorded. Pumping was associated with tactile contact to the spider's abdomen. Pumping increased with increasing frequency of phasic stimuli delivered to the web surface. Attack increased linearly with the log of stimulus frequencies between 0 and 14 Hz for stimuli delivered to the catching spiral. Dropping occurred only when high frequencies and amplitudes of stimuli were administered to the spider's abdomen and the hub of the web.     

Sugarbeet leaf disc culture: an improved procedure for inducing morphogenesis

In preparation for gene transfer experiments we investigated factors that might affect the production of shoots and somatic embryos from the wound callus of cultured sugarbeet leaf discs. A complex interaction was found between the leaf disc plating density, the disc culture medium, the source-shoot culture medium and the frequency of disc transfer to fresh medium. The most productive protocol utilized: source shoots maintained on MS medium containing 0.25 mg 1^-1 BA; multiple leaf discs (ten 4-mm discs/plate) plated onto an enriched modification of MS medium (RV) containing 1.0 mg 1^-1 BA and solidified with 0.3% Gelrite (not permitted to dry during hardening); and transfer of the discs to fresh medium every two weeks during the first month. This standard protocol produced more callus per plate and higher rates of morphogenesis per unit dry weight of callus than did the one-step method of Saunders and Doley. Water availability considerations were found to be critical to obtaining high morphogenic rates. Root induction frequency and quality was superior on shoots transplanted to MS medium containing 1 mg 1^-1 NAA as the sole growth regulator compared to IAA at the same concentration.Abbreviations BA N⁶-benzyladenine - IAA indole-3-acetic acid - NAA -naphthaleneacetic acid     

Sexual differentiation in quail: Conversion of androgen to estrogen mediates testosterone-induced demasculinization of copulation but not other male characteristics

Previous research has shown that administration of either testosterone or estradiol to male quail embryos will demasculinize behavior and morphology. Six experiments in which embryos were treated were conducted to test the hypothesis that this testosterone-induced demasculinization is due to conversion of testosterone to estrogen (aromatization). In Experiment 1, dihydrotestosterone propionate, a nonaromatizable androgen, failed to demasculinize copulatory behavior, but did demasculinize crowing, strutting, and proctodeal glands. In Experiment 2, injection of the aromatizable androgens testosterone propionate (TP), testosterone, or androstenedione demasculinized copulatory behavior, the nonaromatizable androgen androsterone failed to have such an effect, and all androgens demasculinized proctodeal glands. In Experiment 3, Silastic implants of testosterone demasculinized all male characteristics, whereas implants of androsterone demasculinized only proctodeal glands. In Experiment 4, the antiestrogen tamoxifen prevented TP from demasculinizing copulatory behavior, but had no such effect with respect to crowing and strutting. In Experiments 5 and 6, the aromatization inhibitor 1,4,6-androstatrien-3,17-dione (ATD) prevented TP but not estradiol benzoate from demasculinizing copulatory behavior. Thus (1) in quail, testosterone-induced demasculinization of copulatory behavior is due to androgen aromatization, whereas testosterone-induced demasculinization of crowing, strutting, and proctodeal glands is not; (2) the distinct components of normal male reproductive behavior exhibit different patterns of steroid specificity during the organizational period, as was previously shown for the activational period; (3) the steroid specificity of crowing, strutting, and proctodeal glands changes between the organizational and activational periods. During organization, there is little specificity, whereas during activation, these characteristics respond only to androgens, never to estrogens. This difference suggests that developmental changes have occurred in the underlying biochemical substrates.     

Improved high-performance liquid chromatography of the new antineoplastic agents bisantrene and mitoxantrone

Bisantrene and mitoxantrone are two new anthracene derivatives which have shown significant antitumor activity against a wide variety of animal tumors and in human phase I and II clinical trials. We have developed a rapid, simple and sensitive sample cleanup procedure and high-performance liquid chromatographic (HPLC) assay for both drugs. This method uses a commercially available mini-cartridge with C₁₈ reversed-phase packing to isolate the drugs from the biological matrix prior to HPLC. For both drugs the average recovery of the assay was 98 ± 6% with a coefficient of variation (C.V.) of less than 7%. Using this new method our assay sensitivity has improved to less than 10 ng/ml for bisantrene and 1 ng/ml for mitoxantrone, allowing us to document a prologned terminal phase plasma half-life for both bisantrene and mitoxantrone. Equilibrium dialysis studies showed that both drugs are highly protein bound. Mitoxantrone appears less stable in human plasma than bisantrene. Recoveries from plasma after a 24-h incubation at 25 and 37°C were 40 and 20% for mitoxantrone and 90 and 85% for bisantrene, respectively. Addition of ascorbic acid prior to incubation of mitoxantrone in human plasma at 37°C resulted in less than a 10% decrease in the latter's concentration over a 24-h period. To maintain sample integrity, all plasma samples should be fortified with ascorbic acid and kept frozen prior to analyses.     

Mitochondrial DNA in yeast recombination and subsequent modification following mating between a grande and a suppressive petite

Summary The fluorinated pyrimidines 5-fluorouracil (5FU) and 5-fluorocytosine (5FC) induce the cytoplasmic petite mutation in the yeastSaccharomyces cerevisiae with high efficiency. It was found that in order to induce the mutation, 5FC must first be deaminated to 5FU. However, mutagenesis does not depend on the further conversion of 5FU to its deoxyriboside (5FUDR) and subsequent blockade of intracellular thymidine synthesis, since 5FUDR itself was found not to be mutagenic, and 5FU-induced mutagenesis was not antagonised by supplying thymidine monophosphate (dTMP) to a dTMP permeable strain. In any case, observations of the molecular changes accompanying petite induction in log phase cells ruled out the possibility that mutagenesis resulted simply from the dilution out of replication-blocked mitDNA molecules, since the appearance of mutants coincided with the synthesis of altered mitDNA molecules. In different strains, the resulting defective molecules were either maintained, giving rise to suppressive ^– petites, or completely degraded, to give pure clones of neutral ⁰ mutants. It is suggested that this degradative process was a consequence of the incorporation of 5FU into RNA.     

Advance of mitosis by histone phosphokinase

The previous observation that growth-associated histone kinase (HKG) from Ehrlich ascites cells brings forward mitosis in Physarum polycephalum has been confirmed with more step 1 histone kinase and a more purified (step 2) histone kinase and the statistical significance of the results assessed. The mitosis appears normal in the phase contrast microscope and DNA synthesis is initiated after mitosis as usual. In vitro the growth-associated histone kinase phosphorylates chromatin, the phosphate appearing in F 1 histone. The results are interpreted as providing support for the hypothesis that growth-associated histone kinase controls the initiation of mitosis through F 1 histone phosphorylation and chromosome condensation.