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Experimental and analytical results are reported for radiant wall to bed heat transfer in fluidized beds. The experiments were carried out by transmitting heat from a source through a transparent wall and by maintaining the wall at the bulk bed temperature. It was thus possible to achieve purely radiative heat transfer at source temperature as low as 600°K. The results were interpreted in terms of a model postulating transient radiative heat transfer from source to the particles during their finite residence time at the wall. By using the analysis an estimate was made of the operating conditions under which thermal radiation is likely to make a significant contribution to the overall heat transfer mechanism in real systems, (where radiation and convection occur simultaneously).

The aerobic and anaerobic energy linked transhydrogenase reactions have been demonstrated in membrane preparations from E. , coli . The aerobic transhydrogenase activity could be enhanced by an energy transfer factor prepared from rat-liver mitochondria. These reactions were sensitive to 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole, an uncoupler of oxidative phosphorylation.

The energy-linked nicotinamide adenine dinucleotide transhydrogenase from Escherichia coli can be driven by energy obtained from ATP or from respiration. E. coli grown anaerobically has the ATP-driven transhydrogenase but no respirationdriven transhydrogenase activity. The ATP-driven activity is inhibited by 50 μM N , N ′-dicyclohexylcarbodiimide (DCCD) in membrane particles prepared from both aerobically and anaerobically grown cells, but the respiration-driven transhydrogenase is not inhibited. Low levels of DCCD enhance the respiration-driven transhydrogenase activity in membrane particles prepared from aerobically grown cells. The oxidation of NADH is one-fifth as low in particles prepared from anaerobically grown cells and is less sensitive to KCN than in particles from aerobically grown cells. The results suggest that anaerobically grown E. coli can produce and utilize the nonphosphorylated high-energy intermediate from ATP. However, this membrane appears to be depleted in its ability to transduce oxidative energy to form the high-energy intermediate.

The ATP-Pi exchange activity of highly purified preparations of ‘ATP synthetase’ was inhibited by F1-antiserum, Pullman inhibitor, azide and also by avidin (See You and Hatefi, 1973) . The inhibition produced by the first three was relieved in the presence of ADP, and the avidin sensitivity was lost on pretreatment on the avidin with biotin. It is concluded that the ATP-Pi exchange resulted from the combined action of Factor A and a contaminating avidin-sensitive enzyme. The ADP necessary for the exchange reaction catalyzed by the latter was generated by the ATPase activity of Factor A.

Retroviral Gag proteins encode small peptide motifs known as late domains that promote the release of virions from infected cells by interacting directly with host cell factors. Three types of retroviral late domains, with core sequences P(T/S)AP, YPXnL, and PPPY, have been identified. HIV-1 encodes a primary P(T/S)AP-type late domain and an apparently secondary late domain sequence of the YPXnL type. The P(T/S)AP and YPXnL motifs interact with the endosomal sorting factors Tsg101 and Alix, respectively. Although biochemical and structural studies support a direct binding between HIV-1 p6 and Alix, the physiological role of Alix in HIV-1 biology remains undefined. To elucidate the function of the p6–Alix interaction in HIV-1 replication, we introduced a series of mutations in the p6 Alix binding site and evaluated the effects on virus particle production and virus replication in a range of cell types, including physiologically relevant primary T cells and macrophages. We also examined the effects of the Alix binding site mutations on virion morphogenesis and single-cycle virus infectivity. We determined that the p6–Alix interaction plays an important role in HIV-1 replication and observed a particularly severe impact of Alix binding site mutations when they were combined with mutational inactivation of the Tsg101 binding site.

The solution structure of a 24.4 kDa specific complex of the DNA-binding domain (DBD) of the human ETS1 (hETS1) oncoprotein with a 17-mer DNA has been solved by NMR. The interaction of the hETS1 DBD with DNA reveals a surprising twist on the general features of helix-turn-helix (HTH)-DNA interactions. Major groove recognition involves the C-terminal two thirds of the HTH recognition helix, while minor groove recognition occurs via true intercalation of the side chain of Trp-28, which extends from the minor to the major groove. This results in a sharp kink of approximately 60 degrees and a widening of the minor groove over one-half turn of the DNA. The orientation of the HTH element of the hETS1 DBD with respect to the major groove is significantly rotated relative to other HTH proteins. These observations establish the ETS family of DNA-binding proteins as a distinct family of HTH proteins.

The fact that Lie algebra homomorphisms can be extended to Lie group homomorphisms, provided the source is simply connected, is well-known. The situation in the non-simply connected case is less clear. In this paper, we show how ideas from differential geometry provide a unifying viewpoint about such extension problems. In particular, the holonomy bundle of a flat invariant connection plays a central role.

To better understand the process of the cellular transformation and conversion of proto-oncogenes to the transforming retroviral oncogenes, our laboratory has pursued the study of the normal cellular genes comparing these to the homologous viral oncogemes. We have focused on the ets gene family which are related to sequences originally identified as a second cellular derived genes transduced by the avian leukemia virus, E26 (Watson et al. 1985). In mammals there are three ets genes located on two different chromosomes, termed ets-1, ets-2 and erg. The ETS-1 gene most related to the cellular ets captured by the virus (v-ets) is located in chromosome 11; the ETS-2 and ERG genes are located on chromosome 21. In higher mammals as well as humans these ets genes, are dispersed in separate chromosomes; but retain their homologous syntenic groups with respect to other genetic markers (Watson et. al. 1986). The ets genes are transcriptionally active, their gene products are homologous to one another and they are differentially regulated. Figure 1 presents a diagramatic comparison of the amino acid sequences of a wide variety of species ranging from Drosophila to humans.

The study of gene expression in cells and tissues often begins with phenol-chloroform extraction of the biologic material of interest for the isolation of intact mRNA. In most cases, the proteins denatured by phenol-chloroform are discarded. However, we found that the proteins recovered from phenol-chloroform extractions maintain their antigenicity. Therefore a method was developed for recovering the proteins from phenol-chloroform-denatured extracts that could be saved in lyophilized form until immunologic analysis. In this way, the RNA and the protein analysis can utilize exactly the same sample, and the biologic material can be saved. This is important because often these materials are available only in limited quantities. The method has been used to examine the sea urchin ets-related antigen and sea urchin ets-2 mRNA.

Our previously reported data from DNA sequence studies of the c-myc locus show that the human c-myc exon 1 has an open reading frame capable of encoding a protein of 188 amino acid residues. To confirm the presence of the open reading frame, we constructed a recombinant vector (pMCP60) that contains a segment of the lambda cII translational initiation region, a portion of the N-terminus of the v-mos gene, and 639 base pairs of the first exon of the human c-myc gene. pMCP60 expresses a 38 kilodalton tripartate protein (cII-mos-myc), which was purified by high-pressure liquid chromatography. The presence of myc exon 1 sequences in the cII-mos-myc fusion protein was confirmed by partial amino acid sequence analysis. These experiments further establish that the first exon of the human c-myc gene contains an open reading frame capable of expressing a protein in Escherichia coli.

The expression of ets genes has been studied in mouse tissues and regenerating murine liver, an in vivo model for cell proliferation. Our results indicate that the ets-1 and ets-2 loci are transcriptionally active; the ets-2 locus encodes a major mRNA (3.5 kilobases) and is expressed in most of the tissues examined, whereas the ets-1 locus encodes a major 5.3-kilobase and minor 4.0-, 2.5-, and 2.2-kilobase RNA species and is expressed at a high level in thymus; both ets-1 and ets-2 mRNA are abundant in young proliferating tissues and are greatly reduced in terminally differentiated tissues, except thymus; compensatory growth of liver induces ets-2 mRNA before DNA synthesis, but after fos and myc induction; and ets-2 mRNA, but not ets-1 mRNA, is stabilized in the presence of cycloheximide during hepatic regeneration. These results suggest that ets-2 gene expression is intrinsically linked with cell proliferation. Thus, ets-2 expression follows a pattern similar to other members of the nuclear oncogene family. During hepatic regeneration, the ets-1 and ets-2 loci are subject to differential regulation.

The maximal decline of adenosine triphosphate phosphohydrolase (ATPase; EC 3.6.1.3) in mitochondria from regenerating rat liver on treatment with chloramphenicol occurs between 48 and 72 h after partial hepatectomy. The depleted mitochondria are well coupled, exhibiting a respiratory control ratio of about 7 with succinate. These mitochondria are fully sensitive to rutamycin for the inhibition of succinate state 3 respiration. In frozen-thawed mitochondria there is a 60% reduction in ATPase activity, and of this remaining ATPase activity only 50% is sensitive to rutamycin. The titers for release of succinate state 4 respiration and ATPase activity by 5-Cl, 3-tert-butyl, 2′-Cl, 4′-NO2-salicylanilide are decreased, and the efficiency of the uncoupler is increased. The antimycin titer for inhibition of succinate state 3 respiration is decreased. In all cases where a decrease in activity or titer was observed it is about the same (50%), suggesting inhibition at a common site for these parameters.

The feature that defines a cancer cell is its ability to propagate under conditions that typically inhibit the growth of the normal cell. In cells where the genetic constitution remains unaltered, restraints on growth are imposed by regulatory activities that take place at the cell surface. These activities, which may be due to either cell contact or a decrease in the production and availability of growth factors, are communicated through the cytoplasm to the nucleus, thus regulating the synthesis of messenger RNAs essential for the unique proteins needed to initiate subsequent DNA synthesis and mitosis. Cells can be relieved of this barrier to mitosis by cell dispersal or addition of growth factors; this molecular environmental change is similarly recognized at the surface of the cell, and is transmitted through the cytoplasm to the nucleus. This signal transduction process activates the transcription and synthesis of specific proteins and other macromolecules that trigger the mitotic process. The process and events leading to cell division are called here the “mitogenic signal pathway”.

A nitrogenase system that remains in the supernatant fluid after centrifuging for 3 hr at 180,000 × g can be extracted from Azotobacter vinelandii by osmotic lysis of the bacteria. This nitrogenase preparation is oxygen-labile and appears to be similar, though not identical, to that obtained from Clostridium pasteurianum . The particulate characteristic and oxygen stability of previously described preparations are likely due to the method of cell disruption, e.g., in the French pressure cell. The data support a nitrogenase model system in the intact cell in which oxygen-labile enzymes are protected from oxygen by the extensive internal membranous system which Azotobacter synthesize only when they fix nitrogen.

We are developing computer-aided methods for designing nano-scale structures built of RNA. As the first step we created the RNAJunction database, which is a repository of RNA junctions (i.e. internal loops and kissing-loop interactions), and which can be used as a source of building blocks for nanostructures. These building blocks, combined with idealized fragments of A-form helices, can be used by two programs developed in our laboratory, NanoTiler and RNA2D3D, to produce desired 3D nano structures. In the initial stages of nano-scale shape design, the building blocks are treated as rigid or near-rigid objects. However, since experimental data shows that RNA accommodates its shape to the constraints of larger structural contexts, we are adding analysis of the flexibility of our building blocks to the overall design process. Here we present examples of RNA-based nanostructure designs, with the stress on the characterization of the structural flexibility of the building blocks and potential approaches to controlling these characteristics. Examples focus on the use of kissing loops (KL) in nanostructure design, since they show potential for introducing angular junctions necessary to produce regular polygonal shapes. We compare and contrast reprogrammed KLs based on the HIV-1 KL complex, already experimentally proven, with the dynamic behavior of other kissing loops some of which have been used in experimental assembly and others which are being experimentally evaluated. In some cases flexible KLs appear to be absolutely required for the assembly of larger shapes, while in others an alternative design, bypassing geometrically useful but potentially unstable KLs can be a better strategy.Funded in part by NCI contract HHSN261200800001EThis research was supported by the Intramural Research Program of the NIH, National Cancer Institute, Center for Cancer Research.

International audience; Although intensively transgressed by advertisers, next to nothing has been written on the subject of taboos in marketing. Based on a multi-field approach (anthropological, sociological and psychoanalysis), a conceptualization of the taboo is proposed and a reliable and valid measurement of this construct in an advertising context is developed. Using this scale, the communication effects of taboo ads are investigated. The use of taboos in ads leads to a more negative attitude toward the ad which carries over into negative attitude toward the brand and negative purchase intention. The utility of the proposed scale is discussed both for future research and advertising strategy.