Differences in response to simulated herbivory between <Emphasis Type="Italic">Quercus crispula</Emphasis> and <Emphasis Type="Italic">Quercus dentata</Emphasis>

To evaluate the responses of Quercus crispula and Quercus dentata to herbivory, their leaves were subjected to simulated herbivory in early spring and examined for the subsequent changes in leaf traits and attacks by chewing herbivores in mid summer. In Quercus crispula, nitrogen content per area was higher in artificially damaged leaves than in control leaves. This species is assumed to increase the photosynthetic rate per area by increasing nitrogen content per area to compensate leaf area loss. In Quercus dentata, nitrogen content per area did not differ between artificially damaged and control leaves, while nitrogen content per mass was slightly lower in artificially damaged leaves. The difference in their responses can be attributable to the difference in the architecture of their leaves and/or the severeness of herbivory. The development of leaf area from early spring to mid summer was larger in artificially damaged leaves than in control leaves in both species, suggesting the compensatory response to leaf area loss. Leaf dry mass per unit area was also larger in artificially damaged leaves in both species, but the adaptive significance of this change is not clear. In spite of such changes in leaf traits, no difference was detected in the degree of damage by chewing herbivores between artificially damaged and controlled leaves in both species.     

Effect of moisture content on the expansion volume of popped Amaranth seeds by hot air and superheated steam using a fluidized bed system

The effect of the initial moisture content (X(0)) of amaranth seeds on expansion volume after popping was examined in hot air and superheated steam (SHS), using a fluidized bed system (FBS). The moisturized seeds were prepared under various vapor pressures due to various saturated salt solutions. In hot air, the maximum expansion volume was shown by seeds having X(0) of 0.16 at 260 degrees C for 15 sec, reaching 8.7-fold of the pre-popped seeds. Heating by SHS decreased the volume slightly. Thus, popping of amaranth seeds is influenced not only by the moisture content of the seeds, but also by moisture in the heat media.     

Nitric oxide synthase induction,cGMP elevation,and biopterin synthesis in vascular smooth muscle cells stimulated with interleukin-1beta in hypoxia

In cultured rat vascular smooth muscle cells (VSMC), inducible nitric oxide synthase (iNOS) expression evoked by interleukin-1beta (IL-1beta) or tumor necrosis factor-alpha was greatly enhanced in hypoxia (2% O(2)), compared to in normoxia. In contrast, iNOS induction by interferon-gamma, lipopolysaccharide or their combination was barely influenced by hypoxia. These results indicate that iNOS induction is regulated by hypoxia in different manners, depending on the stimuli in VSMC. Nitric oxide (NO) production in response to stimulation with interferon-gamma plus lipopolysaccharide was significantly decreased in hypoxia, due to a decrease in the concentration of O(2) as a substrate. In contrast, the level of NO production in hypoxia was almost the same as that in normoxia when the cells were stimulated by IL-1beta. In addition, cGMP increased in response to IL-1beta in hypoxia to a level comparable to that in normoxia. Thus, it seems that the IL-1beta-induced expression of iNOS is up-regulated in hypoxia to compensate for a decrease in the enzyme activity due to the lower availability of O(2) as a substrate, and consequently a sufficient amount of NO is produced to elevate cGMP to an adequate level. In addition, the IL-1beta-induced synthesis of tetrahydrobiopterin, a cofactor for iNOS, was also greatly stimulated by hypoxia in VSMC.     

Selective cytotoxic mechanism of GTP-14564, a novel tyrosine kinase inhibitor in leukemia cells expressing a constitutively active Fms-like tyrosine kinase 3 (FLT3)

The receptor tyrosine kinase FLT3 is constitutively activated by an internal tandem duplication (ITD) mutation within the juxtamembrane domain in 20-30% of patients with acute myeloid leukemia. In this study, we identified GTP-14564 as a specific kinase inhibitor for ITD-FLT3 and investigated the molecular basis of its specificity. GTP-14564 inhibited the growth of interleukin-3-independent Ba/F3 expressing ITD-FLT3 at 1 microM, whereas a 30-fold higher concentration of GTP-14564 was required to inhibit FLT3 ligand-dependent growth of Ba/F3 expressing wild type FLT3 (wt-FLT3). However, this inhibitor suppressed the kinase activities of wt-FLT3 and ITD-FLT3 equally, suggesting that the signaling pathways for proliferation differ between wt-FLT3 and ITD-FLT3. Analysis of downstream targets of FLT3 using GTP-14564 revealed STAT5 activation to be essential for growth signaling of ITD-FLT3. In contrast, wt-FLT3 appeared to mainly use the MAPK pathway rather than the STAT5 pathway to transmit a proliferative signal. Further analysis demonstrated that the first two tyrosines in an ITD were critical for STAT5 activation and growth induction but that all of the tyrosines in the juxtamembrane region were dispensable in terms of the proliferation signals of wt-FLT3. These results indicate that an ITD mutation in FLT3 elicits an aberrant STAT5 activation that results in increased sensitivity to GTP-14564. Thus, FLT3-targeted inhibition is an attractive approach, with the potential for selective cytotoxicity, to the treatment of ITD-FLT3-positive acute myeloid leukemia.     

Distribution and trafficking of MPR300 is normal in cells with cholesterol accumulated in late endocytic compartments: evidence for early endosome-to-TGN trafficking of MPR300

It has been reported that an accumulation of cholesterol within late endosomes/lysosomes in Niemann-Pick type C (NPC) fibroblasts and U18666A-treated cells causes impairment of retrograde trafficking of the cation-independent mannose 6-phosphate/IGF-II receptor (MPR300) from late endosomes to the trans-Golgi network (TGN). In apparent conflict with these results, here we show that as in normal fibroblasts, MPR300 localizes exclusively to the TGN in NPC fibroblasts as well as in normal fibroblasts treated with U18666A. This localization can explain why several lysosomal properties and functions, such as intracellular lysosomal enzyme activity and localization, the biosynthesis of cathepsin D, and protein degradation, are all normal in NPC fibroblasts. These results, therefore, suggest that the accumulation of cholesterol in late endosomes/lysosomes does not affect the retrieval of MPR300 from endosomes to the TGN. Furthermore, treatment of normal and NPC fibroblasts with chloroquine, which inhibits membrane traffic from early endosomes to the TGN, resulted in a redistribution of MPR300 to EEA1 and internalized transferrin-positive, but LAMP-2-negative, early-recycling endosomes. We propose that in normal and NPC fibroblasts, MPR300 is exclusively targeted from the TGN to early endosomes, from where it rapidly recycles back to the TGN without being delivered to late endosomes. This notion provides important insights into the definition of late endosomes, as well as the biogenesis of lysosomes.     

General method for sequence-independent site-directed chimeragenesis

We have developed a simple and general method that allows for the facile recombination of distantly related (or unrelated) proteins at multiple discrete sites. To evaluate the sequence-independent site-directed chimeragenesis (SISDC) method, we have recombined beta-lactamases TEM-1 and PSE-4 at seven sites, examined the quality of the chimeric genes created, and screened the library of 2(8) (256) chimeras for functional enzymes. Probe hybridization and sequencing analyses revealed that SISDC generated a random library with little sequence bias and in which all targeted fragments were recombined in the desired order. Sequencing the genes from clones having functional lactamases identified 14 unique chimeras. These chimeras are characterized by a lower level of disruption, as calculated by the SCHEMA algorithm, than the library as a whole. These results illustrate the use of SISDC in creating designed chimeric protein libraries and further illustrate the ability of SCHEMA to identify chimeras whose folded structures are likely not to be disrupted by recombination.     

Nitrogen dioxide air pollution near ambient levels is an atherogenic risk primarily in obese subjects: a brief communication

Ambient exposure to nitrogen dioxide, a critical air pollutant in developed countries, is positively associated with cardiovascular mortality and morbidity. Although its cardiovascular effects are predominantly shown in patients with high risk of atherogenesis, no studies have elucidated whether daily exposure to nitrogen dioxide air pollution enhances atherogenic metabolisms, primarily in obese subjects who are susceptible to atherogenesis and subsequent cardiovascular diseases. We used male Otsuka Long-Evans Tokushima Fatty (OLETF) rats as obese subjects and Long-Evans Tokushima (LETO) rats as nonobese controls. The animals were continuously exposed to nitrogen dioxide at a concentration of 0, 0.16, 0.8, or 4.0 ppm from 8 weeks of age through 32 weeks. At 40 weeks of age, levels of body weight, triglyceride, and total cholesterol were significantly greater in the OLETF rats than in the LETO rats. A ratio of high-density lipoprotein (HDL) to total cholesterol was significantly smaller in the former than in the latter. In the LETO rats, nitrogen dioxide exposure significantly decreased only the levels of HDL as compared with clean air exposure. In the OLETF rats, however, nitrogen dioxide exposure at a concentration of 0.16 ppm significantly elevated triglyceride concentration and decreased the ratio of HDL to total cholesterol as well as the levels of HDL. Nitrogen dioxide air pollution near ambient levels is an atherogenic risk primarily in obese subjects.     

LiCl inhibits the establishment of left-right asymmetry in larvae of the direct-developing echinoid Peronella japonica

The effect of LiCl on the establishment of left-right (LR) asymmetry in larvae of the direct-developing echinoid Peronella japonica was investigated with special attention to the location of the amniotic opening and ciliary band pattern. The larvae of echinoids are LR symmetric, but shortly before metamorphosis the larval LR symmetry is lost as a result of the formation of an amniotic cavity (vestibule), part of the adult rudiment, on the left side of the body. P. japonica has been considered to be the only exception among the echinoids, because the amniotic cavity forms at the midline of the larval body. In the present study we discovered the following two different LR asymmetric traits in larvae of P. japonica: the opening of the amniotic cavity initially forms at the midline of the larval body but shifts to the left dorsal side, and a looped ciliary band that initially forms with LR symmetry becomes LR asymmetric as a result of the formation of a bulge on left dorsal side. The establishment of LR asymmetry in both the location of the amniotic opening and the change in the shape of the ciliary band was influenced by exposing embryos to LiCl. Quantitative analysis of the shift in amniotic opening showed that exposure of embryos to LiCl causes repression of leftward shifting of the amniotic opening in earlier stage larvae, and leftward or rightward shifting in later stage larvae. These findings suggest that LiCl is an effective means of impairing the establishment of LR asymmetry in sea urchin embryos.     

Highly stable and efficient mRNA templates for mRNA-protein fusions and C-terminally labeled proteins

For high-throughput in vitro protein selection using genotype (mRNA)-phenotype (protein) fusion formation and C-terminal protein labeling as a post-selection analysis, it is important to improve the stability and efficiency of mRNA templates for both technologies. Here we describe an efficient single-strand ligation (90% of the input mRNAs) using a fluorescein-conjugated polyethylene glycol puromycin (Fluor-PEG Puro) spacer. This ligation provides a stable c-jun mRNA with a flexible Fluor-PEG Puro spacer for efficient fusion formation (70% of the input mRNA with the PEG spacer) in a cell-free wheat germ translation system. When using a 5' untranslated region including SP6 promoter and Omega29 enhancer (a part of tobacco mosaic virus Omega), an A(8) sequence (eight consecutive adenylate residues) at the 3' end is suitable for fusion formation, while an XA(8) sequence (XhoI and the A(8) sequence) is suitable for C-terminal protein labeling. Further, we report that Fluor-PEG N-t-butyloxycarbonylpuromycin [Puro(Boc)] spacer enhances the stability and efficiency of c-jun mRNA template for C-terminal protein labeling. These mRNA templates should be useful for puromycin-based technologies (fusion formation and C-terminal protein labeling) to facilitate high-throughput in vitro protein selection for not only evolutionary protein engineering, but also proteome exploration.