Identification of carrot cDNA clones encoding a second putative proliferating cell-nuclear antigen, DNA polymerase delta auxiliary protein.

The proliferating cell-nuclear antigen (PCNA) plays a key role in the control of eukaryotic DNA replication. We have isolated two cross-hybridizing groups of cDNA encoding carrot homologs of PCNA. Sequence analysis and Southern-blot experiments showed that the cDNA were derived from two distinct genes. One corresponded to the typical PCNA, which is known to be highly conserved in eukaryotes from yeast to man; its mRNA is 1.2 kb in size and the calculated molecular mass of the protein is 29 kDa. The other encoded a larger PCNA homolog which has not previously been reported; the mRNA is 1.5 kb in size, the N-terminal three quarters (calculated molecular mass, 29 kDa) of the protein product is 88% identical at the amino acid level to the typical PCNA, but the protein has an extra C-terminal domain of 11 kDa. Both PCNA homologs were apparently coexpressed concomitant with somatic embryogenesis. The mRNA level of the novel homolog is 10-20% that of the typical PCNA in the embryos. The presence of the second putative PCNA may provide new insight into studies on the mechanism of DNA replication in eukaryotes.     

Rapid detection of a minute amount of lipopolysaccharide from Salmonella in large volumes by poly(ethyleneimine)-cloth enzyme immunoassay

Utilizing the rapidity in capturing Salmonella lipopolysaccharide (LPS) and the macroporous nature of poly(ethyleneimine) immobilized polyester cloth (PEI-cloth), a PEI-cloth disk set in a Swinnex cartridge joined at both ends with 10 ml plastic syringes was repeatedly passed through with an LPS sample in large volumes. The captured LPS on the disk were detected at up to 1 pg, which is equivalent to the amount produced of 16 cells, by cloth enzyme immunoassay.     

Brain Correlates of Self-Evaluation Deficits in Schizophrenia: A Combined Functional and Structural MRI Study

Self-evaluation plays an important role in adaptive functioning and is a process that is typically impaired in patients with schizophrenia. Underlying neural mechanisms for this dysfunction may be associated with manifested psychosis. However, the brain substrates underlying this deficit are not well known. The present study used brain blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) and gray matter voxel-based morphometry to explore the functional and structural brain correlates of self-evaluation deficits in schizophrenia. Eighteen patients with schizophrenia and 17 healthy controls were recruited and asked to judge whether a set of personality-trait adjectives were appropriate for describing themselves, a familiar other, or whether the adjectives were of positive or negative valence. Patients had slower response times for negative trait attributions than controls did; responses to positive trait attributions were faster than those for negative traits among the patient group, while no differences were observed in the control group. Control subjects showed greater activation within the dorsal medial prefrontal cortex (dMPFC) and the anterior cingulate cortex (ACC) than the patient group during the self-evaluation > semantic positivity-evaluation contrast. Patients showed greater activation mainly within the posterior cingulate gyrus (PCC) as compared to controls for the other-evaluation > semantic positivity-evaluation contrast. Furthermore, gray matter volume was reduced in the MPFC, temporal lobe, cuneus, and the dorsal lateral prefrontal cortex (DLPFC) among the patient group when compared to controls. The present study adds to previous findings regarding self- and other-referential processing in schizophrenia, providing support for neurobiological models of self-reflection impairment.     

Trophic polymorphism in bluegill sunfish (<Emphasis Type="Italic">Lepomis macrochirus</Emphasis>) introduced into Lake Biwa: evidence from stable isotope analysis

Trophic polymorphism was recently reported in introduced bluegill (Lepomis macrochirus) in Lake Biwa, Japan, where three morphs are specialized in benthic invertebrates (benthivorous type), submerged aquatic plants (herbivorous type), and zooplankton (planktivorous type). We evaluated the long-term effects of food resource utilization by these trophic morphs using stable isotope ratios, δ¹⁵N and δ¹³C. A significant difference in δ¹⁵N was found between the benthivorous and planktivorous types. The planktivorous type had the higher δ¹⁵N value, which corresponded with the value expected from its prey, zooplankton. The lower δ¹⁵N value of the benthivorous type would be derived from the lower δ¹⁵N values of benthic prey organisms compared to zooplankton. These results support previous findings that the benthivorous and planktivorous types have different food resource utilization. In contrast, the δ¹⁵N and δ¹³C values of the herbivorous type were distinctly different from the expected values, indicating that this type was unlikely to utilize aquatic plants substantially, contradicting the results of the dietary analysis.     

Two new supermolecular structures of organic-inorganic hybrid compounds: [Zn(phen)(SO4)(H2O)2]n and [Cu(phen)(H2O)2] · SO4 (phen = 1,10-phenanthroline)

Two new organic-inorganic hybrid compounds [Zn(phen)(SO₄)(H₂O)₂]_n (1) and [Cu(phen)(H₂O)₂] · SO₄ (2) have been prepared by conventional aqueous solution synthesis and characterized by single-crystal X-ray diffraction, IR spectroscopy, thermal gravimetric analysis (TGA) and fluorescent spectroscopy. In compound 1, the sulfate group adopts bidentate mode to coordinate with two Zn(II) ions to form one-dimensional polymer. The one-dimensional polymers are further linked together via the intermolecular hydrogen-bonding and π-π stacking interactions to form a 3D supramolecular framework. Compound 2 is build up of discrete [Cu(phen)(H₂O]²⁺ cations and SO₄²⁻ anions to form a three-dimensional framework via hydrogen-bonding and π-π stacking interactions. Furthermore, the luminescent properties of both 1 and 2 were studied. The complexes 1 and 2 excited at 280 nm wavelength produced characteristic luminescence features, arising maybe due to the π-π transitions.     

Viscoelastic and light scattering studies on thermally induced sol to gel phase transition in fish myosin solutions

Viscoelastic (VE) and dynamic light scattering (DLS) analyses of fish (white croaker) myosin solutions were performed at myosin concentrations of 30 mg/mL for VE and 0.1 mg/mL for DLS at 0.6M KCl and pH 7.0 to clarify thermally induced gelation. The hydrodynamic radius R(h) considerably decreased around 30-35 degrees C. The shear modulus G was constant below 25 degrees C and increased by incubating the sample at 30 degrees C. G further increased as the temperature of the incubated sample decreased. The curves of G vs T for different time courses showed a sharp peak around 35 degrees C and a moderate peak around 60 degrees C in the heating process, while a stepwise increase in G was observed around 30 degrees C in the cooling process when the temperature was elevated to not more than 60 degrees C. No distinct stepwise change was observed once the temperature of the sample exceeded 60 degrees C. The absolute value of G strongly depended on the maximum elevated temperature and the incubation time at that temperature. The corresponding behavior of the viscosity eta was observed for each time course. Based on these results, the mechanism of thermally induced gelation of myosin solutions is discussed in view of S-S bridge formation in the head and tail portions and unwinding/rewinding of coiled-coil alpha-helices in the tail portion.     

Protein profile of symbiotic bacteria Mesorhizobium loti MAFF303099 in mid-growth phase

Expressed proteins in cultured symbiotic bacteria (Mesorhizobium loti MAFF303099) in the mid-growth phase were proteomically analyzed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and capillary high-performance liquid chromatography coupled with an ion-trap mass spectrometry (MS). The genome sequence data of M. loti were used to identify the analyzed proteins. We identified 114 of the 127 proteins analyzed on 2D-PAGE gel with some microheterogenities which were caused by post-translational modifications.     

cDNA macroarray analysis of gene expression in ineffective nodules induced on the Lotus japonicus sen1 mutant

The Lotus japonicus sen1 mutant forms ineffective nodules in which development is arrested at the stage of bacterial differentiation into nitrogen-fixing bacteroids. Here, we used cDNA macroarray systems to compare gene expression in ineffective nodules induced on the sen1 mutant with gene expression in wild-type nodules, in order to identify the host plant genes that are involved in nitrogen fixation. Macroarray analysis coupled with Northern blot analysis revealed that the expression of 18 genes was significantly enhanced in ineffective sen1 nodules, whereas the expression of 30 genes was repressed. Many of the enhanced genes encoded hydrolase enzymes, such as cysteine proteinase and asparaginase, that might function in the early senescence of sen1 nodules. By contrast, the repressed genes encoded nodulins, enzymes that are involved in carbon and nitrogen metabolism, membrane transporters, enzymes involved in phytohormone metabolism and secondary metabolism, and regulatory proteins. These proteins might have a role in the establishment of nitrogen fixation. In addition, we discovered two novel genes that encoded glutamate-rich proteins and were localized in the vascular bundles of the nodules. The expression of these genes was repressed in the ineffective nodules, which had lower levels of nitrogenase activity.