Endogenous AP-1 levels necessary for oncogenic activity are higher than those sufficient to support normal growth

We investigated the role of endogenous AP-1 in human tumor cell lines by introducing SupJunD-1, a dominant-negative mutant of AP-1, using vesicular stomatitis virus G protein (VSV-G)-pseudotyped retrovirus vectors. Single inoculation of six human tumor cell lines, originating from osteosarcomas, non-small cell lung carcinomas or cervical carcinomas, with recombinant SupJunD-1 virus at a high multiplicity of infection readily inhibited colony formation in soft agar. We detected no significant changes in expression levels of AP-1 components c-Jun or Fra-1, adhesion molecules CD44 or E-cadherin, or cell cycle regulator p53, which are encoded by genes previously reported to be under the control of AP-1 in some mouse or human cell lines. By varying the dosage of VSV-G-pseudotyped retrovirus, we were able to change the proviral copy number of supjunD-1 from 1 to approximately 10 and monitor suppression of endogenous AP-1 function as assessed by growth characteristics of the tumor cell lines, we found a SupJunD-1 dosage which significantly suppressed anchorage-independent growth without affecting the cellular growth in monolayer cultures at all. We conclude that endogenous AP-1 levels necessary for oncogenic activity are much higher than those sufficient to support normal growth.     

A knowledge model for analysis and simulation of regulatory networks

MOTIVATION: In order to aid in hypothesis-driven experimental gene discovery, we are designing a computer application for the automatic retrieval of signal transduction data from electronic versions of scientific publications using natural language processing (NLP) techniques, as well as for visualizing and editing representations of regulatory systems. These systems describe both signal transduction and biochemical pathways within complex multicellular organisms, yeast, and bacteria. This computer application in turn requires the development of a domain-specific ontology, or knowledge model. RESULTS: We introduce an ontological model for the representation of biological knowledge related to regulatory networks in vertebrates. We outline a taxonomy of the concepts, define their 'whole-to-part' relationships, describe the properties of major concepts, and outline a set of the most important axioms. The ontology is partially realized in a computer system designed to aid researchers in biology and medicine in visualizing and editing a representation of a signal transduction system.     

Enhancement of oxidised low-density lipoprotein uptake by macrophages in response to macrophage migration inhibitory factor

We examined the expression of macrophage migration inhibitory factor (MIF) mRNA in murine macrophage cell line (RAW 264.7 cells) in response to oxidized low-density lipoprotein (oxLDL), and investigated the influence of MIF on the uptake and degradation of oxLDL by RAW 264.7 cells. MIF mRNA expression was markedly upregulated in the presence of oxLDL. Consistent with this, the MIF level of the culture medium was increased by stimulation with oxLDL in dose- and time-dependent manners. Next, we added recombinant rat MIF to the culture medium and examined its effects on the uptake of(125)I-labelled oxLDL. Pretreatment with MIF enhanced both the uptake and degradation of(125)I-oxLDL. Taken together, these results suggest that MIF released from macrophages in response to oxLDL stimulates oxLDL uptake and degradation in an autocrine and paracrine fashion, which potentially results in atherosclerosis.     

Clinical effects of elastic bandage on neurogenic orthostatic hypotension

Neurogenic orthostatic hypotension (OH) often causes troublesome symptoms such as dizziness, syncope and falling, interfering active daily life or various therapies in rehabilitation. Nonpharmacologic measures for treating patients with OH include wearing elastic leotard, head-up tilting at night, etc. Elastic garment or antigravity suits is certainly effective, but it may be uncomfortable and not practical. Although elastic bandage (EB) bound on the lower limbs has been thought to be useful, there is few clinical report about its beneficial evidence. We investigated short-term clinical effects of commercially available EB on OH, and estimated the mechanism of its effectiveness by measuring some blood pressure-related humoral variables in neurodegenerative patients with OH.     

Identification of Photosystem I components from a glaucocystophyte,Cyanophora paradoxa: The PsaD protein has an N-terminal stretch homologous to higher plants

Thylakoid membranes and Photosystem I (PS I) complexes were isolated from a glaucocystophyte, Cyanophora paradoxa, which is thought to have the most primitive ‘plastids’, and the proteins related to PS I were examined. The intrinsic light-harvesting chlorophyll protein complexes of PS I (LHC I) were not detected by an immunological method. The PS I complexes consisted of at least eight low-molecular-mass proteins in addition to PS I reaction center proteins. The N-terminal sequence of the PsaD protein has higher homology to that of Chlamydomonas reinhardtii and land plants, than to that of other algae or cyanobacteria. On the other hand, the PsaL sequence has the highest homology to those of cyanobacteria. Taking into account the other sequences of PS I components whose genes are encoded in the cyanelle genome, and the fact that LHC I is not detected, it is concluded that PS I of C. paradoxa has chimeric characteristics of both ‘green’ lineages and cyanobacteria. This revised version was published online in June 2006 with corrections to the Cover Date.     

Microorganisms and plant of Autonomous Biological Systems (ABS) samples.

Distribution of microorganisms and cellular structure of an Autonomous Biological Systems (ABS) were studied with a special attention to the effect of space environments. Viable cell densities measured by the direct fluorescence microscopic method were in the order of 10(5) cells/ml for fractions 1 (upper suspension) and 2 (lower suspension), and 10(6) cells/ml for fraction 3 (sediments). These values were 10 to 100 times larger than the values obtained by the classical colony forming unit method. No difference between flight and ground samples was observed in the vertical distribution of viable microorganisms when fractionation and analysis were carried out after recovery. Intracellular distribution of chloroplasts in higher green plants, Ceratophyllum demersum, of flight samples was disturbed after 10 days of flight (24hrs/day light on). After 4 months of flight (Mir/STS-79/81) with 24 hrs light on, Ceratophyllum demersum was completely disintegrated. On the other hand, in the second 4-months-flight experiment with 16 hrs/day light on, Ceratophyllum demersum was only slightly deteriorated.     

Vegetative compatibility of an isolate ofVerticillium dahliae pathogenic to both tomato and pepper

An isolate ofVerticillum dahliae Vdp-4, pathogenic to both tomato and pepper (tomato-pepper pathotype), was examined for its vegetative compatibility with testers of the Japanese vegetative compatibility group (subgroups J1, J2, and J3). Seven isolates ofV. dahliae from the same field as Vdp-4 in Misato, Nagano Pref. and two isolates from Hokkaido were separately determined as either tomato pathotype (B) or pepper pathotype (C). Isolate 5922 previously reported as tomato-pepper pathotype was also examined. Compatiblenit1 and NitM mutants were obtained from all isolates except for isolates Vdp-3 and Vdt-10. The isolate of tomato-pepper pathotype Vdp-4 showed a strong reaction with VCGJ1 and J3 and was thus assigned to J3. Seven of these isolates showed compatibility and were assigned into three provisional subgroups. The isolate 5922 was self-incompatible.     

Mitochondrial DNA Variation Follows a Geographic Pattern in Japanese Beech Species

The amount and distribution of mitochondrial (mt) DNA restriction fragment length polymorphism was determined among individual tree samples of two Japanese beech species, Fagus crenata and F.japonica. Individual plants were collected from 16 F. crenata populations throughout the range of the species, and from three F. japonica populations. We detected enough variation to characterize eleven and three chondriome types in F. crenata and F.japonica, respectively. The grouping of beech chondriome types based upon the cladistic analysis of mtDNA polymorphism allowed us to recognize the apparent geographical patterns of mtDIMA diversity: the resulting three main groups occupied distinct geographic areas. This geographic differentiation is likely to reflect the history of the Japanese beech forests after the last glacial period of the Pleistocene. In addition, the mtDNA polymorphism encountered within F. crenata encompassed all the variation observed in F.japonica. Our result suggests the need for re-evaluation of their phylogenetic relationships.     

15-Cis-carotenoids found in the reaction center of a green sulfur bacterium Chlorobium tepidum and in the Photosystem I reaction center of a cyanobacterium Synechococcus vulcanus

Carotenoids were extracted, at 4 °C in complete darkness and under nitrogen atmosphere, from the reaction center (RC) of a green-sulfur bacterium and the Photosystem (PS) I RC of a cyanobacterium; each extract was subjected to high-performance liquid chromatography (HPLC) using an apparatus equipped with a two-dimensional diode-array detector in order to spectroscopically identify cis–trans carotenoids while performing HPLC analysis. In the extract from the RC of Chlorobium tepidum, 15-cis and all-trans--carotenes as well as 13-cis-, 15-cis- and all- trans-chlorobactenes (in the order of elution) were identified, whereas in the extract from the PS I RC of Synechococcus vulcanus, 15-cis-, all-trans- and 9-cis--carotenes were found. Thus, the universal presence of 15- cis carotenoids in the 'iron sulfur-type' RCs has been shown in addition to the previous cases of the 'quinone-type' RCs.