Hybridization of a mouse T-cell lymphocyte line (HB1) with a polyoma virus-transformed mouse fibroblast line

The establishment of permanent T-lymphocyte cell lines by transformation with DNA viruses has not yet been achieved. This paper reports the successful transfer of polyoma virus genome into T-lymphocyte cells by somatic hybridization. A T-lymphocyte clone, HB₁, derived from (DBA/ 2J×AKR) spleen cells, isolated in vitro by cloning in semi-solid agar, was fused with a polyoma (Py) virus-transformed fibroblast C3HPy, clone 1. The authenticity of the hybrid C3H/HB was established by chromosome and histocompatibility antigen studies. This initial population and the various clones retained T-lymphocyte characteristics such as morphological appearance, growth properties (suspension culture) and differentiation antigen (Thy 1–2). The hybrid cell line and the various clones presented all the characteristics of Py transformation. Namely, they carried the Py genome originating from the fibroblastic parent and maintained Py virus tumour-associated antigens (TSTA, TSSA and T antigens). In most respects, this hybrid population resembled the C3HPy/C11 parent and exhibited the same tumorigenicity.     

Nucleolar localization of ‘template-bound’ RNA polymerase I in nuclei of Xenopus laevis blastulae

This study shows, by means of autoradiography, that RNA polymerase I activity is present in some of the nuclei isolated from Xenopus blastulae. This activity is localized in one or two nucleoli which have a diameter of at least 1.5 μm. The ratio between nucleolar and total nuclear grain counts allows a quantitative estimation of RNA polymerase I activity relative to total RNA polymerase activity at the blastula stage.     

Galactosyltransferase activities in subcellular fractions of two YC8 lymphoma cell variants: does a relationship exist between antigenic determinants and acceptor sites for galactose?

Experiments have been undertaken to correlate physiological changes, observed in two YC8 cells variants (P and L) and some of their immunological and enzymatic properties. These cell lines show different responses towards antilymphocyte and anti-Moloney sera. Subcellular fractionations have been made. The A fractions (d: 1.14/1.16) have the highest ouabain-inhibited Mg²⁺-stimulated (Na⁺-K⁺)-dependent ATPase and galactosyltransferase activities. Some properties of the latter enzyme have been studied: whereas optima pH and requirements for Mn²⁺ ions have been found to be the same for both cell line enzymes, on the contrary, different kinetic parameters have been shown with respect to sugar donor (UDP-galactose) on endogeneous or exogeneous (ovomucoid) acceptors. Apparent Km for UDP-galactose is 1.7 × 10⁻⁶ M (P-cells) and 3.3 × 10⁻⁶ M (L-cells), on endogeneous acceptors, and P-cell V max < L-cell V max; on ovomucoid it is 0.61 × 10⁻⁶ M, for both cell lines. These results suggest the presence on L-cells of more endogeneous acceptor sites, the higher affinity of P-cells for UDP-galactose being balanced by less endogeneous acceptor sites for galactose. When ovomucoid is added, galactose transfer on endogeneous acceptor sites of both cells is negligible. Apparent Km for ovomucoid is 8.6 × 10⁻⁵ M (P-cells) and 4.3 × 10⁻⁵ M (L-cells). These data support the above-mentioned hypothesis: L-cell enzymes would be more rapidly saturated than P-cell enzymes because of the higher number of endogeneous sites on L-cells.This supposed acquired character of L-cells as well as their immunological behaviour could explain the modified properties of L-cells as compared to P-cells.     

Role de l'intensite lumineuse rouge (630–670 nm) dans le determinisme photoperiodique de la diapause nymphale de Pieris brassicae

In previous communications we have reported the role of red light on the determinism of the pupal diapause of Pieris brassicae (630 to 670 nm, wavelengths corresponding to the maximum of absorption of pterobilin, the blue bile pigment present in the integument and haemolymph).Red light suppresses the diapausing effect of the 9-hr/24-hr photophase of white light (identical energy in both and similar to the energy under natural conditions). The activity of red light in two experimental conditions: 9-hr white light followed by 15 hr of red lights of different intensities, and 9-hr red lights of different intensities followed by 15 hr darkness is examined. The photoperiodic determinism of pupal diapause is discussed.     

Transmission experiments with pike fry (Esox Indus L.) rhabdovirus

Experimental infection of fertilized pike eggs with 'red-disease' virus produced 100% mortality in the fry. This mortality was associated with a disease that had previously been described as hydrocephalus internus, indicating that 'red-disease' and hydrocephalus are different manifestations of the same disease. The name pike fry rhabdovirus disease (PFRD) is suggested for the disease complex, and the name pike fry rhabdovirus (PFR) for the causative agent. Exposure of PFR to a Wescodyne * solution containing 25 ppm of iodine resulted in an inactivation of at least 99–99% of viral activity within 30 sec. Experimental egg transmission of PFR could be interrupted by disinfecting the eggs in a Wescodyne solution, suggesting that the virus was located on the egg surface. Conclusive evidence of a naturally occurring vertical transmission in pike culture is still lacking because, using FHM cells as a detection system, PFR could not be found in spawners and their sexual products. The susceptibility of pike fry to PFR rapidly decreases at increasing age.     

Hastifolins A–G,antifeedant neo-clerodane diterpenoids from Scutellaria hastifolia

From the aerial parts of Scutellaria hastifolia, family Lamiaceae (Labiatae), seven neo-clerodane diterpenoids (hastifolins A–G) were isolated. The products are similar to the known scuteparvin and are characterized by being trans-cinnamoyl derivatives. Structures and stereochemistry were determined by intensive NMR investigation. Six of the products form three pairs of epimers at C-13. Hastifolins A–C showed significant antifeedant activity.     

Rational Design of Core@shell Structured CoSx@Cu2MoS4 Hybridized MoS2/N,S‐Codoped Graphene as Advanced Electrocatalyst for Water Splitting and Zn‐Air Battery

A novel hybrid of small core@shell structured CoS_x@Cu₂MoS₄ uniformly hybridizing with a molybdenum dichalcogenide/N,S‐codoped graphene hetero‐network (CoS_x@Cu₂MoS₄‐MoS₂/NSG) is prepared by a facile route. It shows excellent performance toward the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in alkaline medium. The hybrid exhibits rapid kinetics for ORR with high electron transfer number of ≈3.97 and exciting durability superior to commercial Pt/C. It also demonstrates great potential with remarkable stability for HER and OER, requiring low overpotential of 118.1 and 351.4 mV, respectively, to reach a current density of 10 mA cm^?2. An electrolyzer based on CoS_x@Cu₂MoS₄‐MoS₂/NSG produces low cell voltage of 1.60 V and long‐term stability, surpassing a device of Pt/C + RuO₂/C. In addition, a Zn‐air battery using cathodic CoS_x@Cu₂MoS₄‐MoS₂/NSG catalyst delivers a high cell voltage of ≈1.44 V and a power density of 40 mW cm^?2 at 58 mA cm^?2, better than the state‐of‐the‐art Pt/C catalyst. These achievements are due to the rational combination of highly active core@shell CoS_x@Cu₂MoS₄ with large‐area and high‐porosity MoS₂/NSG to produce unique physicochemical properties with multi‐integrated active centers and synergistic effects. The outperformances of such catalyst suggest an advanced candidate for multielectrocatalysis applications in metal‐air batteries and hydrogen production.     

Impact of Noncovalent Sulfur–Fluorine Interaction Position on Properties,Structures, and Photovoltaic Performance in Naphthobisthiadiazole‐Based Semiconducting Polymers

Controlling the energetics and backbone order of semiconducting polymers is essential for the performance improvement of polymer‐based solar cells. The use of fluorine as the substituent for the backbone is known to effectively deepen the molecular orbital energy levels and coplanarize the backbone by noncovalent interactions with sulfur of the thiophene ring. In this work, novel semiconducting polymers are designed and synthesized based on difluoronaphthobisthiadiazole (FNTz) as a new family of naphthobisthiadiazole (NTz)–quaterthiophene copolymer systems, which are one of the highest performing polymers in solar cells. The effect of the fluorination position on the energetics and backbone order is systematically studied. It is found that the dependence of the solar cell fill factor on the active layer thickness is very sensitive to the fluorination position. It is thus further investigated and discussed how the structural features of the polymers influence the photovoltaic parameters as well as the diode characteristics and bimolecular recombination. Further, the polymer with fluorine on both the naphthobisthiadiazole and quaterthiophene moieties exhibits a quite high power conversion efficiency of 10.8% in solar cells in combination with a fullerene. It is believed that the results would offer new insights into the development of semiconducting polymers.