A method for studying tissue specificity of maternally affected Drosophila melanogaster mutants: mosaic analysis of cinnamon.

Mosaic analysis is introduced to study tissue specificity of the maternal effect which characterizes the wild-type allele of cinnamon (=cin). The methodology presented is applicable to studies of other maternal effect mutations, as well as to female or male sterility mutations. One hundred and forty-three pal-induced fertile cin-mosaic females were obtained, and the degree to which they were capable of maternally affecting their homozygous cin daughters was correlated to their cuticular and germinal genetic constitution. From this analysis the following conclusions are drawn: (1) The presence of a wild-type (cin⁺) allele in maternal germ cells constitutes a sufficient condition for the full expression of the cin⁺ characteristic maternal effect: All cin offspring derived from such cells have normal viability and eye color. (2) This effect is confined to the descendants of a particular germ cell and does not extend to the descendants of other non-cin⁺ germ cells in the same or in a neighboring ovary. (3) A wild-type allele in a germ cell constitutes a necessary condition for the eye color maternal effect. (4) When a maternal germ line is wholly mutant, nonmutant constitution of an additional focus may result in rescue of more than half of the homozygous cin offspring (all with mutant eye color). Mosaic analysis suggests that this somatic viability focus originates from the posterior region of the blastoderm. These conclusions were tested and confirmed by transplanting heterozygous cin ovaries, wild-type Malphigian tubes, and wild-type fat body into homozygous cin hosts. In addition, transplantations of homozygous cin ovaries into wild-type hosts suggest that the posterior maternal viability focus corresponds to the mesodermal components of the ovaries.     

The effects of the antiestrogen CI-628 on sexual behavior activated by androgen or estrogen in quail

This series of experiments sought to determine whether conversion of androgen to estrogen is important in the activation of male sexual behavior in quail by seeing if an antiestrogen will block androgen stimulated copulation in this species. Experiment I compared the ability of two antiestrogens, MER-25 (5 mg/day) and CI-628 (2 mg/day), to block estrogen stimulated characteristics in female quail. Both treatments greatly reduced oviduct growth in “photically castrated” females given estradiol benzoate (EB, 50 μg/day), but only CI-628 reduced receptivity in these birds. In Experiment II surgically castrated males given 50 μg/day EB together with 2 mg/day CI-628 were much less receptive than castrated males given EB alone, and in addition copulated in fewer tests. In Experiments III, IV, and V, castrated males given testosterone propionate (TP) together with CI-628 were compared with males given TP alone. The ability of CI-628 to suppress TP-stimulated copulation increased with increasing CI/TP dosage ratio, and at the highest ratio (4:1), CI-628 effectively blocked copulation in five out of seven birds. Those birds that did copulate did so in fewer tests and performed fewer cloacal contact movements. CI-628 had no antiandrogenic effects in these experiments. These results suggest that estrogens may be important active metabolites of testosterone with respect to quail copulation.     

Hormones and social behavior in the lizard, Anolis carolinensis

The purpose of this experiment was to study the effects of homologous and heterologous gonadal hormones on sexual and aggressive behavior in a reptilian species. Thirty adult male and thirty adult female lizards (Anolis carolinensis) were divided into 10 groups of six each (five groups per sex) and each group was given one of five treatments: either left intact, sham-castrated and injected with the hormone vehicle, castrated and injected with the hormone vehicle, castrated and injected with estradiol benzoate, or castrated and injected with testosterone propionate. After a week of visual isolation and daily hormone injection, animals were tested four times, twice with a stimulus animal of each sex. Females treated with estrogen were receptive, but did not court. Females treated with androgen were receptive and also courted and pursued stimulus females as frequently as males given androgen. No males in any group were receptive, and thus the female appears to be more capable of heterotypical sexual behavior than the male. Castrated males failed to court. Courtship and pursuit of stimulus females was readily stimulated in males with testosterone, and weakly stimulated by estrogen. Intact males were very aggressive, but lower levels of aggression were independent of gonadal hormones, as was subordination (head-nodding). The results for aggression and subordination are interpreted with reference to naturally-occurring Anolis behavior, and the results for sexual behavior are compared with similar experiments with mammals and birds.     

Ethanol-induced changes in lipid composition of Escherichia coli: Inhibition of saturated fatty acid synthesis in vitro

Growth of Escherichia coli in the presence of ethanol results in the synthesis of lipids containing elevated proportions of unsaturated fatty acids. Previous in vivo experiments indicated that the ethanol-induced changes in fatty acid composition result from a preferential inhibition of saturated fatty acid synthesis. In this study, the inhibition of saturated fatty acid synthesis by ethanol was confirmed in vitro. This inhibition was not membrane mediated and resulted from a direct action of ethanol on the soluble enzymes of fatty acid synthesis. The addition of ethanol resulted in a decrease in chain length of both saturated and unsaturated acyl products in vitro. Experiments with enzymes prepared from several fatty acid synthesis mutants of E. coli indicate that β-hydroxydecanoyl-acyl carrier protein dehydrase is not the site of the ethanol inhibition of saturated fatty acid synthesis. The two condensing enzymes are the probable sites for inhibition by ethanol.     

Characterization of Metabolic,Diffusion, and Perfusion Properties in GBM: Contrast-Enhancing versus Non-Enhancing Tumor

BACKGROUND: Although the contrast-enhancing (CE) lesion on T₁-weighted MR images is widely used as a surrogate for glioblastoma (GBM), there are also non-enhancing regions of infiltrative tumor within the T₂-weighted lesion, which elude radiologic detection. Because non-enhancing GBM (Enh?) challenges clinical patient management as latent disease, this study sought to characterize ex vivo metabolic profiles from Enh? and CE GBM (Enh+) samples, alongside histological and in vivo MR parameters, to assist in defining criteria for estimating total tumor burden. Methods: Fifty-six patients with newly diagnosed GBM received a multi-parametric pre-surgical MR examination. Targets for obtaining image-guided tissue samples were defined based on in vivo parameters that were suspicious for tumor. The actual location from where tissue samples were obtained was recorded, and half of each sample was analyzed for histopathology while the other half was scanned using HR-MAS spectroscopy. Results: The Enh+ and Enh? tumor samples demonstrated comparable mitotic activity, but also significant heterogeneity in microvascular morphology. Ex vivo spectroscopic parameters indicated similar levels of total choline and N-acetylaspartate between these contrast-based radiographic subtypes of GBM, and characteristic differences in the levels of myo-inositol, creatine/phosphocreatine, and phosphoethanolamine. Analysis of in vivo parameters at the sample locations were consistent with histological and ex vivo metabolic data. CONCLUSIONS: The similarity between ex vivo levels of choline and NAA, and between in vivo levels of choline, NAA and nADC in Enh+ and Enh? tumor, indicate that these parameters can be used in defining non-invasive metrics of total tumor burden for patients with GBM.     

Reaction of celite-bound fluorescein isothiocyanate with the 50S E. coli ribosomal subunit

The reaction of Celite-bound fluorescein isothiocyanate with E. coli 50S ribosomes and the 50S moiety of the intact 70S particle has been studied. Approximately five dyes react per 50S particle at pH 8.6 or 9.0. Substantial biological activity is retained. No significant difference between the pattern of reactivity of free and complexed 50S particle can be detected. This suggests the absence of major shielding or conformational changes induced in the 50S by combination with the 30S subunit. The most reactive proteins are L1, L2, L3, and L21. Protein L3 is found in 1.5 and 3 m LiCl core particles where it is still very reactive toward fluorescein. Some other core particle proteins are more reactive than they are in the intact ribosome. In general this work supports previous findings that the proteins of the intact 50S subunit are much less exposed than those of the 30S particle.     

Helix-coil equilibria of poly (rA) · poly (rU)

Absorbance melting curves of the double-stranded (rA) · (rU) helix, made with fractionated homopolynucleotides of matched length, have been obtained over a 15-fold range of [Na⁺] and 30° range of temperature. An excellent fit of the observed profiles was obtained with theoretical curves calculated on the basis of the simplest interpretation for the occurrence of particular equilibria [1–3]; the complete molecular partition function being evaluated by the power series method developed by Applequist [4–6]. The stability constant was evaluated from literature values for the calorimetric enthalpy. The loop closure exponent was best represented by 2.22 ± 0.04 for the mismatching loop mode of melting and 1.22 for the matching mode and was independent of [Na⁺] and temperature. Assuming the applicability of the nonintersecting random walk value of 1.9 ± 0.1, these results would suggest a slight bias toward matched loop formation during melting of homopolynucleotides that might be expected to form only mismatched loops. The value of the stacking parameter at 60°C was only ~6% higher than that at 30°C, 0.0221 (0.0184 for the matching case). Calculated melting curves indicate the occurrence of a fifth-order phase transition when the mean helix length is only ~13 base-pairs, or about one full turn of the helix.     

Gulps, wheezes, and sniffs: how measurement of beak movement in sea turtles can elucidate their behaviour and ecology

This study was performed to assess the extent to which an intermandibular angle sensor (IMASEN) may be used to elucidate the behaviour of six captive loggerhead turtles. The measuring system was glued to the beak of turtles and set to measure the intermandibular distance at 5 Hz while the turtles fed (on anchovies, squid, and live crabs), swam, rested, and breathed. The behaviour of the equipped turtles was filmed and compared afterwards to the sensor readings. The IMASEN output data allowed quantification of the number of food items ingested as well as the time between food seizure and deglutition and the type of food ingested. However, nonfeeding turtles exhibited regular jaw movements with a reduced amplitude of ca. 2.2 mm, which clearly differed from feeding movements and were caused by buccal oscillations. Such movements of the base of the buccal cavity generate a steady flow of water pass the chemosensory organs and were interrupted only during food ingestion, resting, and breathing. Breathing was clearly distinguishable by the IMASEN. The beak sensor is thus a reliable system to investigate a number of behaviours in sea turtles which encompass foraging, buccal oscillation, and respiratory frequency. It has potential for allocating time to different activities in free-ranging sea turtles and thus allows us to gain insight to their foraging and diving strategies.     

Binding of prostacyclin by plasma glycoproteins

The binding of prostacyclin (PGI₂) to plasma proteins and the resulting increase in PGI₂ stability was investigated. Using gel filtration to separate bound and free PGI₂, we have found that Cohn Fraction VI can bind PGI₂, and retard its hydrolysis to 6-keto-PGF₁ (6KPGF₁). The biological activity of the bound PGI₂ correlated well with the quantity of bound PGI₂, measured as 6KPGF₁ by RIA. Fraction VI bound a greater percentage of PGI₂ than the other eicosanoids tested (i.e., PGI₂ > TXB₂ > LTB₄ > PGE₁ > PGF₂). The PGI₂ binding activity of Fraction VI was lost after neuraminidase treatment. Our data suggest that Fraction VI glycoproteins may play an important role in the binding and stabilization of PGI₂ by plasma proteins.