The effects of gibberellic acid upon developmental processes in Drosophila hydei

The injection of gibberellic acid (GA₃) into larvae of Drosophila hydei can affect the pattern of gene activities in a specific manner. This became clear from a study on the pattern of puffs in the giant chromosomes of the larval salivary glands.Depending upon the age of the larvae injected, either of two new puffs, 72B or 21B, appeared. Not only was the activity of these chromosome regions stimulated but the activity of some normally occurring puffs specific for the period shortly before puparium formation was affected. If GA₃ was injected during the period shortly before puparium formation further development became influenced as revealed by a significant reduction in the number of flies emerging from treated animals.

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Zusammenfassung Es wurde die Wirkung verschiedener Konzentrationen von Gibberellinsäure (GA₃) nach Injektion in Drosophila-Larven unterschiedlichen Alters untersucht. Konzentrationen von 3 g/Larve und höher führten bei jungen und mittleren Larven des 3. Stadiums zur Ausbildung eines neuen Puffs (72B) in den polytänen Chromosomen der Speicheldrüse. Diese Reaktion wurde in 15–20% der Larven beobachtet.In späteren Stadien der Entwicklung kurz vor der Pupariumbildung wird nach Injektion von 1 g/Larve ein weiterer Puff (21B) in 10% der Larven induziert. Der Prozentsatz der Larven die diesen Puff 3 Stunden nach der Injektion aufweisen, nimmt mit steigender GA₃-Konzentration zu. Nach Injektion von 5–6 g/Larve war der Puff 21B in 80% der Tiere enthalten.Zur selben Zeit ließ sich eine Beinflussing der Aktivität von zwei Puffs nachweisen, die für die Periode der Pupariumbildung spezifisch sind. Die Aktivität dieser Puffs wird durch die Injektion von GA₃ herabgesetzt.GA₃ bewirkt nicht nur die Induktion neuer Puffs, sondern außerdem eine Verzögerung der Entwicklung. Nach der Injektion von 2 g/Larve verzögert sich die Zeit der Pupariumbildung um 2–10 Stunden. Die Zahl der Fliegen, die aus Larven schlüpfte, die kurz vor der Pupariumbildung eine Injektion von mehr als 3 g GA₃ erhielten, war deutlich herabgesetzt. Es wird vermutet, daß GA₃ eine spezifische Wirkung auf die Aktivität des Genoms ausübt und damit eine Beeinflussung der normalen Entwicklung bewirkt.

     

No influence of number of donor CFU-GM on granulocyte recovery in bone marrow transplantation for acute leukemia

The possible interrelation between infused bone marrow CFU-GM and peripheral granulocyte recovery was studied in 16 patients transplanted for acute leukemia. The influence of several clinical events that could modify the graft fate were also analysed. Our results show that: 1) There was no correlation between the number of infused nucleated cells and granulocyte recovery. 2) There was no correlation between the number of infused CFU-GM and granulocyte regeneration. 3) There were significant differences between the day of engraftment in patients with clinically documented HSV infection compared to patients without infection.     

Locations of Z-DNA in polytene chromosomes

In polytene chromosomes of Drosophila hydei and D. melanogaster, Z-DNA was identified in varying distribution after different conditions for fixation were used. When salivary glands were fixed and squashed in 50% acetic acid alone, Z-DNA was found in the less dense DNA regions, such as interbands, some puffs, and a few of the less dense bands. Prefixation that combined ethanol and acetic acid exposure led to prominent immunofluorescent staining of the bands, generally but not strictly correlating with the total DNA content. Separate exposure to ethanol and acetic acid did not cause this band to stain, but if residual ethanol was present after ethanol fixation, subsequent exposure to acid did cause it. Under the more selective acid fixation conditions, Z-DNA reactivity was seen in portions of certain ecdysone-inducible puffs in the induced but not in the resting state; in other inducible regions, the Z-DNA immunoreactivity was not changed on induction. Z-DNA was also identified in polytene chromosomes within isolated nuclei that had been frozen and fixed in ethanol without exposure to acid; this Z-DNA was present in regions of low DNA density.     

Chromosomal DNA denaturation and reassociation in situ.

The degree of chromosomal DNA (cDNA) denaturation and renaturation on polytene chromosomes has been measured by UV microspectrophotometry. Also DNA losses occurring upon denaturation have been quantified by Feulgen, gallocyanin-chromalum and UV. It has been observed that denaturation in alkali (0.07 N NaOH at room temperature) and formamide (90% formamide; 0.1 SSC, pH 7.2) at 65 °C removes about 30% of the DNA. Low DNA loss occurs upon denaturation in HCl (0.24 M) at room temperature and 60% formamide: 2 × 10^?4 M EDTA (pH 8) at 55 °C. The presence of 4% formaldehyde in the denaturation buffer prevents DNA loss. After denaturation of chromosomes in 0.1 × SSC containing 4% formaldehyde at 100 °C for 30 sec, an hyperchromicity of 39 °C is observed. The denaturation efficiency varies with the denaturation treatment. The percentage reassociation was measured from the difference in the UV absorption of renatured chromosomes and that of denatured chromosomes from the same set. It seems that in our conditions DNA:DNA reassociation does not occur. The efficiency of hybridization is proportional to the denaturation extent of the DNA. However, the entire fraction of DNA which has been denatured is not available for hybridization.     

Comparative study of immunobiological activities ofPseudomonas aeruginosa andBrucella melitensis lipopolysaccharides

The toxic activity ofBrucella melitensis andPseudomonas aeruginosa lipopolysaccharides as well as their behavior as immunogens, mitogens, and interferon inducers have been studied. Although their toxicities were very similar, the former molecule was incapable of eliciting a primary immune response in mice. Rabbit hyperimmunization gave titers half of those obtained withP. aeruginosa lipopolysaccharide. Optimal mitogenic responses of spleen cell cultures were obtained using 10–50 μg/ml and 50–100 μg/ml ofPseudomonas andBrucella lipopolysaccharide, respectively, giving the latter a lower stimulation of³H-thymidine uptake. Interferon titers induced in chickens byBrucella lipopolysaccharide were three times lower than those obtained withPseudomonas lipopolysaccharide.     

Class III homeodomain-leucine zipper gene family members have overlapping, antagonistic, and distinct roles in Arabidopsis development

The Arabidopsis thaliana genome contains five class III homeodomain-leucine zipper genes. We have isolated loss-of-function alleles for each family member for use in genetic analysis. This gene family regulates apical embryo patterning, embryonic shoot meristem formation, organ polarity, vascular development, and meristem function. Genetic analyses revealed a complex pattern of overlapping functions, some of which are not readily inferred by phylogenetic relationships or by gene expression patterns. The PHABULOSA and PHAVOLUTA genes perform overlapping functions with REVOLUTA, whereas the PHABULOSA, PHAVOLUTA, and CORONA/ATHB15 genes perform overlapping functions distinct from REVOLUTA. Furthermore, ATHB8 and CORONA encode functions that are both antagonistic to those of REVOLUTA within certain tissues and overlapping with REVOLUTA in other tissues. Differences in expression patterns explain some of these genetic interactions, whereas other interactions are likely attributable to differences in protein function as indicated by cross-complementation studies.     

Intrinsically fluorescent cytotoxic cisplatin analogues as DNA marker molecules

Two square planar derivatives of Pt(en)Cl(2) with intrinsic fluorescence in aqueous solution at room temperature, with quantum yields (Phi) 0.11 and 0.10, respectively, have been synthesized and characterized as [Pt(en)(CG)Cl] (Complex 1) and [Pt(en)(CG)(2)] (Complex 2) (en = ethylenediamine, CG = cholylglycinate). Complexes 1 and 2 exchange just one ligand (chloride or cholylglycinate, respectively) when reacted with water or 5'-GMP to give the same chemical species. After reaction with DNA oligonucleotides or DNA plasmids, they show enhanced emission in the visible region, which lasts for long periods of time and makes them potentially useful DNA marker molecules. Incubation with nucleated blood cells followed by microscopic analyses revealed that they enter the cells within minutes of exposure, selectively stain the DNA, and persist after more than 48 h of exposure. Complexes 1 and 2 display cell cycle phase-independent cytotoxic activity against cisplatin-resistant CHO (Chinese hamster ovarian) tumor cells, with an early onset of their effects. Their slightly different biological effects, as compared to cisplatin, are considered to be linked to the bile acids and their vector properties and to the preferential formation of monoadducts.     

Soluble interleukin-2 receptor (sCD25) and interleukin-10 plasma concentrations are associated with severity of primary respiratory syncytial virus (RSV) infection

The role of the immune response in the severity of RSV infection was examined by determining plasma concentrations of interferon-gamma (IFN-gamma), interleukin-10 (IL-10), interleukin-2 receptor (sCD25) and soluble tumor necrosis factor receptor II (sTNFR-II) in 196, previously healthy infants, during acute and convalescence phases of primary RSV infection. The results were analyzed separately for days 1-4 (early) and days 5-7 (late) of symptoms before sample collection and according to disease severity (105 hypoxic, 91 non-hypoxic). Significant associations between plasma levels and severity were found in early samples only. IL-10 and sCD25 concentrations were higher (p=0.01, each) in hypoxic compared with non-hypoxic infants, whereas no differences were observed in IFN-gamma and sTNFR-II levels between the groups. Early sCD25 levels correlated positively with IL-10 concentrations (p= 0.0003; r= 0,401). Amongst the hypoxic infants, the number of days of oxygen supplementation correlated positively with early IL-10 levels (p=0.009; r=0.495) and negatively with the IFN-gamma/IL-10 ratio (p=0.007; r=0.495). IFN-gamma levels were significantly higher in the acute phase than during convalescence for hypoxic and non-hypoxic infants, while IL-10 levels were significantly higher in the acute phase only in hypoxic infants for days 1-4 (early; p=0.0007). sCD25 concentrations were elevated only in hypoxic infants at days 1-4 of the acute phase (p=0.002), whereas sTNFR-II levels did not vary between acute and convalescence phases, independent of severity and time point of sampling. We found no association between plasma levels during the convalescence phase and the severity of the RSV infection.