Action of aldosterone on frog skin in the presence and absence of in vitro molting effects

The molting which occurs in frog skin following exposure to high concentrations of aldosterone interferes with the interpretation of physiological measurements. Exposure of skins from frogs maintained in standard smooth tanks to 5 · 10^?7 M aldosterone caused within a few hours erratic responses in short-circuit current I₀ and conductance κ followed by sustained stimulation of I₀ and κ; 10^?8 M aldosterone caused only stimulation of I₀ and κ. Storage of frogs in “rough tanks” eliminated in vitro molting on exposure to 5 · 10^?7 M aldosterone. I₀ and κ were then superimposable for 3 h, after which I₀ increased far more rapidly than κ. These results are consistent with an early effect on permeability of the active pathway and later effects on metabolism, either a direct effect on the pump or enhanced interaction between transport and metabolism.     

Cloning and characterization of the immunity region of phage ?80

Summary The immunity region of phage 80 has been localized. It codes for at least three proteins: a protein of 34 kDa which has the biological properties of the phage repressor, and two other proteins of 9 kDa and 18 kDa which are the first proteins on the rightward operon. These two proteins are negatively regulated by the 34 kDa protein at a divergent promoter site. By position analogy with phage , but not by its biological activity, the 9 kDa protein could be the cro roduct. The 18 kDa protein is able to block totally UV induction of phage 80.     

Dexamethasone inhibition and phorbol myristate acetate stimulation of plasminogen activator in human embryonic lung cells

Treatment of human embryonic lung cells with dexamethasone resulted in a decrease in plasminogen activator activity measured in the fibrinolytic assay. The decrease in activity could at least partially be explained by the presence of an inhibitory substance(s) based on the following observations of lysates of dexamethasone-treated vs. control cells: a) an increase in specific activity following subcellular fractionation; b) an increase in fibrinolytic activity following separation by gel electrophoresis; c) an increase in fibrinolytic activity following mild acid-treatment; and d) a decrease in urokinase-directed fibrinolytic activity in mixing experiments. Phorbol myristate acetate increased plasminogen activator activity without affecting the level of inhibitory substance.     

Tween 80解除乙醇对内切葡聚糖酶(Cx)的抑制作用

通过还原糖量的测定,可知Cx酶在乙醇存在下活力降低。当该体系中加入一定浓度的Tween 80时,Cx酶抗乙醇抑制的能力增强。由紫外光谱及圆二色谱可见,乙醇使Cx酶中α-螺旋含量增加,Tween 80使Cx酶中α-螺旋含量减少,结构变得松散。适量的Tween 80能使Cx酶在乙醇中保持一种具有较高活力的构象。     

The effect of paclobutrazol on in vitro rooting,transplant establishment and growth of fruit plants

The effect of paclobutrazol on in vitro rooting and growth of sour cherry (Prunus cerasus) rootstock CAB 11E clone, of S 749 × S 1490 (Prunus persica × Prunus kansuensis) hybrid rootstock, and of pear (Pyrus communis), cv. Abbé Fetel is reported.PP333 increased rooting of S 749 × S 1490 and of Abbé Fetel, particularly at a concentration of 0.5 mg/l (a.i.); moreover, it induced a rooting percentage as high as auxin in the former and hastened rooting of the latter. By contrast, paclobutrazol did not affect root production of 11 E.PP333-treated plants had shorter and thicker roots than controls but similar survival rates during acclimatization. Otherwise they grew less than controls during the first part of the acclimatization phase.Abbreviations used in text and tables BA = 6-benzyladenine - IBA = indole-3-butyric acid - PP333 = paclobutrazol = (2RS,3RS)-1-(-4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pentan-3-ol Part of the results referring to S 749 × S 1490 (P. persica × P. kansuensis) rootstock were presented at the meeting on Controllo della fruttificazione delle piante da frutto, Bologna, Italy, June 1986, and were published in the Riv. Ortoflorofrutt. It. 70 (6)(1986). This research was funded in part by the Italian Ministry of Education (M.P.I. 60%).     

Mechanism of inhibition of eukaryotic translational initiation by the trinucleotide ApUpG

ApUpG, the oligoribonucleotide homologous to the initiation codon, as well as the tetranucleotides ApUpGpA and ApUpGpG block initiation of protein synthesis in the rabbit reticulocyte lysate. These oligonucleotides are recognized as translational initiation sites by the ribosomes, leading to a very large accumulation of complete, but inactive, 80 S initiation complexes, containing methionylated initiator tRNA and ApUpG in a 1:1 stoichiometry. ApUpG appears to inhibit by competing with endogenous globin mRNA for 80 S ribosomal couples, since the inhibition of protein synthesis by ApUpG can be largely relieved by increasing the globin mRNA. The 80 S · Met-tRNA_i^Met · ApUpG complexes are not formed in the absence of hemin, demonstrating that their formation requires the active recycling of eukaryotic initiation factor 2. In addition the trinucleotide correctly directs the Met-tRNA_i^Met into the ribosomal donor site, since the methionyl residue is puromycin-reactive.     

Mesodermal and neural crest derived ovine tibial and mandibular osteoblasts display distinct molecular differences

Mandibular osteoblasts originate from the neural crest and deposit bone intramembranously, mesoderm derived tibial osteoblasts by endochondral mechanisms. Bone synthesized by both cell types is identical in structure, yet functional differences between the two cell types may exist. Thus, both matched juvenile and adult mandibular and tibial osteoblasts were studied regarding their proliferative capacity, their osteogenic potential and the expression of osteogenic and origin related marker genes. Juvenile tibial cells proliferated at the highest rate while juvenile mandibular cells exhibited higher ALP activity depositing more mineralized matrix. Expression of Hoxa4 in tibial cells verified their mesodermal origin, whereas very low levels in mandibular cells confirmed their ectodermal descent. Distinct differences in the expression pattern of bone development related genes (collagen type I, osteonectin, osteocalcin, Runx2, MSX1/2, TGF-β₁, BAMBI, TWIST1, β-catenin) were found between the different cell types. The distinct dissimilarities in proliferation, alkaline phosphatase activity, the expression of characteristic genes, and mineralization may aid to explain the differences in bone healing time observed in mandibular bone when compared to long bones of the extremities.     

Adsorption Behavior of Tween 80 on Soil in the Presence of CdCl2 and DDT

Batch experiments were conducted to investigate the adsorption behavior of Tween 80 in the systems composed of Tween 80, CdCl₂, and/or DDT. The results show that Cd²⁺ from CdCl₂ is the functional fraction influencing the adsorption of Tween 80 to soil, rather than Cl^?. Moreover, DDT can induce the increase of the critical micelle concentration (CMC) of Tween 80, which further impacts the Tween 80 adsorption behavior. The Tween 80 adsorption to soil in the Cd²⁺-DDT coexisted system follows the Langmuir isotherm, as in the Tween 80-Cd²⁺ or -DDT systems. Cd²⁺ and/or DDT decrease(s) the adsorption capacity of Tween 80 to soil, and the magnitude of decrease is dependent on the concentration of coexisting pollutants. Although DDT has a stronger inhibitory effect on Tween 80 adsorption than Cd²⁺ under the same DDT/Cd²⁺ concentrations, the coexistence of Cd²⁺ and DDT has an antagonistic effect on the adsorption of Tween 80. This effect is impacted by the concentrations of the coexisting pollutants, and is a result of the complex interaction among the three pollutants.     

Assays for the Identification of Novel Antivirals against Bluetongue Virus

To identify potential antivirals against BTV, we have developed, optimized and validated three assays presented here. The CPE-based assay was the first assay developed to evaluate whether a compound showed any antiviral efficacy and have been used to screen large compound library. Meanwhile, cytotoxicity of antivirals could also be evaluated using the CPE-based assay. The dose-response assay was designed to determine the range of efficacy for the selected antiviral, i.e. 50% inhibitory concentration (IC₅₀) or effective concentration (EC₅₀), as well as its range of cytotoxicity (CC₅₀). The ToA assay was employed for the initial MoA study to determine the underlying mechanism of the novel antivirals during BTV viral lifecycle or the possible effect on host cellular machinery. These assays are vital for the evaluation of antiviral efficacy in cell culture system, and have been used for our recent researches leading to the identification of a number of novel antivirals against BTV.