Eukaryotes interactions between

Electron Transport Between Photosystem I and Photosystem II Inhibitors. The interaction between PSI and PSII reaction centers (Fig. 1) depends on the thermodynamically favored transfer of electrons from low redox potential carriers to carriers of higher redox potential. This process serves to communicate reducing equivalents between the two photosystem complexes. Photosynthetic and respiratory membranes of both eukaryotes and prokaryotes contain stmctures that serve to oxidize low potential quinols while reducing high potential metaHoproteins (40). In plant thylakoid membranes, this complex is usually referred to as the cytochrome b /f complex, or plastoquinolplastocyanin oxidoreductase, which oxidizes plastoquinol reduced in PSII and reduces plastocyanin oxidized in PSI (25,41). Some diphenyl ethers, eg, 2,4-dinitrophenyl 2 -iodo-3 -methyl-4 -nitro-6 -isopropylphenyl ether [69311-70-2] (DNP-INT), and the quinone analogues,... 

A. Gollotte, C. Cordier, M. C. Lemoine and V. Gianinazzi-Pearson. Role of fungal wall components in interactions between endomycorrhizal symbionts. Eukaryotism and Symbiosis (H. E. A. Schenck, R. Herrmann, K. W. Jeon, N. E. Muller, W. Schwemniler, eds.), Springer-Verlag, 1997, pp. 412-428. 

Plant, Animal and Fungal Eukaryotes and Interactions between them. 282... 

Fig. 10.2. FSPIM analysis of the interaction between maize transcriptional coactivators—GCN5 and ADA2—fused to CFP and YFP. GCN5 is a histone acetyltransferase that, in conjunction with adaptor protein ADA2, modulates transcription in diverse eukaryotes by affecting the acetylation status of the core histones in nucleosomes [63]. CFP- and YFP-tagged proteins, expressed in protoplasts, were excited by the 458 nm and the 514 nm laser lines sequentially. CFP fluorescence was selectively detected by an FIFT 458 dichroic mirror and BP 470-500 band pass emission filter while YFP fluorescence was selectively detected by using an HFT 514 dichroic mirror and...

Tillmann U (2004) Interactions between planktonic microalgae and protozoan grazers. J Eukaryot Microbiol 51 156-168... 

We begin by examining the interactions between proteins and DNA that are the key to transcriptional regulation. We next discuss the specific proteins that influence the expression of specific genes, first in prokaryotic and then in eukaryotic cells. Information about posttranscriptional and translational regulation is included in the discussion, where relevant, to provide a more complete overview of the rich complexity of regulatory mechanisms. 

The Rhizobium-legume symbiosis, an interaction between a prokaryote (Rhizobium) and a eukaryote (legume), requires a series of sequential induction and function of both bacterium-encoded (bac-teroidins) and host-encoded (nodulins) nodule-specific proteins. It has been shown that many plant (Peters et al., 1986 Firmin et al., 1986 Djordjevic et al., 1987 Sadowsky et al., 1988 see also Peters Verma,... 

In eukaryotic cells, a gene consists of the transcribed portion, as well as the 5 and 3 flanking regulatory DNA sequences. Transcription initiation is usually regulated by the 5 regulatory sequences, which include some common DNA elements. One of these elements, the TATA box (TATAAA), is located 25-35 base pairs upstream of the transcription start site for RNA polymerase II, and its function is to direct the transcription at the so-called cap site (Breathnach and Chambon, 1981). The CAAT box (GGCCAATCT) is known to be present upstream of the TATA box. Transcription is initiated by an interaction between these DNA elements and regulatory proteins. 

Multidomain proteins tend to occur more frequently in eukaryotes than in prokaryotes. Often the eukaryotic counterpart to a set of individual prokaryotic enzymes that catalyze successive reactions is a single, multidomain protein. The theoretical advantages proposed for such an arrangement include (1) a geometry for the direct transfer of substrates from one active site to another, in a process known as substrate channeling, in order to increase the overall flux of the pathway, (2) the protection of intermediates that may be unstable in aqueous environments or may be acted on inappropriately by other enzymes, (3) the facilitation of interactions between domains for purposes of allosteric regulatory functions, and (4) the establishment of a fixed stoichiometric ratio of the... 

Because they are easily accessible, glycans displayed on the surface of mammalian cells provide enormous opportunities to bind to many microbial pathogens, ranging from viruses to molecular toxins and from pathogenic bacteria to parasites. In multivalent binding, multiple interactions between ligands and various receptors are common (Fig. 16.1). One representative example is ricin—a versatile and durable A-B-type toxin—in which one of the protein chains (the B chain) is a lectin that interacts and binds terminal galactose (Gal) on the surface of eukaryotic cells with multivalent interactions to facilitate entry of the other peptide chain (the A chain) into the cell to cause cellular death via the catalytic... 

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