An Experimental Test of Trade-Offs Associated with the Adaptation to Alternate Host Plants in the Introduced Herbivorous Beetle, <Emphasis Type="Italic">Ophraella communa</Emphasis>

The adaptation to alternate host plants of introduced herbivorous insects can be vital to agriculture due to the emergence of crop pests. Historically, it is assumed that there are trade-offs associated with the adaptation to new host plants; a generalist genotype that adapts to an alternate host is expected to have a relatively lower fitness on the ancestral host than a specialist genotype (physiological cost) or a relatively lower host-searching ability for the ancestral host plant (behavioral cost). In this study, we tested the costs of adaptation to a new host plant in the introduced herbivorous insect, Ophraella communa LeSage (Coleoptera: Chrysomelidae). In its native range (United States), O. communa feeds mostly on Ambrosia artemisiifolia L. (Asterales: Asteraceae) and cannot utilize the related species, Ambrosia trifida L. (Asterales: Asteraceae), as a host plant. On the other hand, the introduced O. communa population in Japan utilizes A. trifida extensively, and is adapting to it, both physiologically and behaviorally. We compared larval performance on the ancestral and alternate plants and adult host-searching ability between the native and introduced beetle populations. The introduced O. communa showed higher larval survival and adult feeding preference for the alternate host plant A. trifida than did the native O. communa, indicating that the introduced O. communa has rapidly adapted to the alternate host plant. However, there are no differences in either larval performance on the ancestral host A. artemisiifolia or host-searching accuracy between the native and introduced O. communa.     

Expression Profile of Three Splicing Factors in Pleural Cells Based on the Underlying Etiology and Its Clinical Values in Patients with Pleural Effusion

Splicing factors (SFs) are involved in oncogenesis or immune modulation, the common underlying processes giving rise to pleural effusion (PE). The expression profiles of three SFs (HNRNPA1, SRSF1, and SRSF3) and their clinical values have never been assessed in PE. The three SFs (in pellets of PE) and conventional tumor markers were analyzed using PE samples in patients with PE (N = 336). The sum of higher–molecular weight (Mw) forms of HNRNPA1 (Sum-HMws-HNRNPA1) and SRSF1 (Sum-HMws-SRSF1) and SRSF3 levels were upregulated in malignant PE (MPE) compared to benign PE (BPE); they were highest in cytology-positive MPE, followed by tuberculous PE and parapneumonic PE. Meanwhile, the lowest-Mw HNRNPA1 (LMw-HNRNPA1) and SRSF1 (LMw-SRSF1) levels were not upregulated in MPE. Sum-HMws-HNRNPA1, Sum-HMws-SRSF1, and SRSF3, but neither LMw-HNRNPA1 nor LMw-SRSF1, showed positive correlations with cancer cell percentages in MPE. The detection accuracy for MPE was high in the order of carcinoembryonic antigen (CEA, 85%), Sum-HMws-HNRNPA1 (76%), Sum-HMws-SRSF1 (68%), SRSF3, cytokeratin-19 fragments (CYFRA 21-1), LMw-HNRNPA1, and LMw-SRSF1. Sum-HMws-HNRNPA1 detected more than half of the MPE cases that were undetected by cytology and CEA. Sum-HMws-HNRNPA1, but not other SFs or conventional tumor markers, showed an association with longer overall survival among patients with MPE receiving chemotherapy. Our results demonstrated different levels of the three SFs with their Mw-specific profiles depending on the etiology of PE. We suggest that Sum-HMws-HNRNPA1 is a supplementary diagnostic marker for MPE and a favorable prognostic indicator for patients with MPE receiving chemotherapy.     

Proteasome-driven turnover of tryptophan hydroxylase is triggered by phosphorylation in RBL2H3 cells, a serotonin producing mast cell line.

We previously demonstrated in mast cell lines RBL2H3 and FMA3 that tryptophan hydroxylase (TPH) undergoes very fast turnover driven by 26S-proteasomes [Kojima, M., Oguro, K., Sawabe, K., Iida, Y., Ikeda, R., Yamashita, A., Nakanishi, N. & Hasegawa, H. (2000) J. Biochem (Tokyo) 2000, 127, 121-127]. In the present study, we have examined an involvement of TPH phosphorylation in the rapid turnover, using non-neural TPH. The proteasome-driven degradation of TPH in living cells was accelerated by okadaic acid, a protein phosphatase inhibitor. Incorporation of 32P into a 53-kDa protein, which was judged to be TPH based on autoradiography and Western blot analysis using anti-TPH serum and purified TPH as the size marker, was observed in FMA3 cells only in the presence of both okadaic acid and MG132, inhibitors of protein phosphatase and proteasome, respectively. In a cell-free proteasome system constituted mainly of RBL2H3 cell extracts, degradation of exogenous TPH isolated from mastocytoma P-815 cells was inhibited by protein kinase inhibitors KN-62 and K252a but not by H89. Consistent with the inhibitor specificity, the same TPH was phosphorylated by exogenous Ca2+/calmodulin-dependent protein kinase II in the presence of Ca2+ and calmodulin but not by protein kinase A (catalytic subunit). TPH protein thus phosphorylated by Ca2+/calmodulin-dependent protein kinase II was digested more rapidly in the cell-free proteasome system than was the nonphosphorylated enzyme. These results indicated that the phosphorylation of TPH was a prerequisite for proteasome-driven TPH degradation.     

Characterization of Fusarium oxysporum β-1,6-Galactanase, an Enzyme That Hydrolyzes Larch Wood Arabinogalactan

A type II arabinogalactan-degrading enzyme (FoGal1) was purified from Fusarium oxysporum 12S, and the corresponding cDNA was isolated. FoGal1 had high similarity to enzymes of glycoside hydrolase family 5. Treatment of larch wood arabinogalactan with the recombinant enzyme indicated that FoGal1 is a β-1,6-galactanase that preferentially debranches β-1,6-galactobiose from the substrate.     

Probing the role of Valine 185 of the D1 protein in the Photosystem II oxygen evolution

In Photosystem II (PSII), the Mn₄CaO₅-cluster of the active site advances through five sequential oxidation states (S₀ to S₄) before water is oxidized and O₂ is generated. The V185 of the D1 protein has been shown to be an important amino acid in PSII function (Dilbeck et al. Biochemistry 52 (2013) 6824–6833). Here, we have studied its role by making a V185T site-directed mutant in the thermophilic cyanobacterium Thermosynechococcus elongatus. The properties of the V185T-PSII have been compared to those of the WT*3-PSII by using EPR spectroscopy, polarography, thermoluminescence and time-resolved UV–visible absorption spectroscopy. It is shown that the V185 and the chloride binding site very likely interact via the H-bond network linking Tyr_Z and the halide. The V185 contributes to the stabilization of S₂ into the low spin (LS), S?=?1/2, configuration. Indeed, in the V185T mutant a high proportion of S₂ exhibits a high spin (HS), S?=?5/2, configuration. By using bromocresol purple as a dye, a proton release was detected in the S₁Tyr_Z?→?S₂^HSTyr_Z transition in the V185T mutant in contrast to the WT*3-PSII in which there is no proton release in this transition. Instead, in WT*3-PSII, a proton release kinetically much faster than the S₂^LSTyr_Z?→?S₃Tyr_Z transition was observed and we propose that it occurs in the S₂^LSTyr_Z?→?S₂^HSTyr_Z intermediate step before the S₂^HSTyr_Z?→?S₃Tyr_Z transition occurs. The dramatic slowdown of the S₃Tyr_Z?→?S₀Tyr_Z transition in the V185T mutant does not originate from a structural modification of the Mn₄CaO₅ cluster since the spin S?=?3?S₃ EPR signal is not modified in the mutant. More probably, it is indicative of the strong implication of V185 in the tuning of an efficient relaxation processes of the H-bond network and/or of the protein.     

Iron dependence of tryptophan hydroxylase activity in RBL2H3 cells and its manipulation by chelators.

Tryptophan hydroxylase requires Fe2+ for in vitro enzyme activity. In this study, the intracellular activity of tryptophan hydroxylase was assessed by applying 3-hydroxybenzylhydrazine (NSD-1015), an inhibitor of aromatic l-amino acid decarboxylase, to monolayer cultures of RBL2H3 cells, a serotonin producing mast cell line. The effect of manipulating intracellular 'free' iron levels on enzyme activity was analyzed by administration of iron chelators. Desferrioxamine (DFO) suppressed the intracellular enzyme activity. Salicylaldehyde isonicotinoyl hydrazone (SIH) also suppressed enzyme activity, but stimulated it when administered in the Fe-bound form. Hemin also stimulated enzyme activity, which progressively increased over several hours to more than sixfold the initial level. DFO and SIH inhibited the hemin stimulatory effect when administered simultaneously with hemin. Both suppression and stimulation with these chelators took place without a significant decrease or increase in the amount of enzyme. These results indicate that there was an inadequate supply of Fe2+ in the cells to support full activity of tryptophan hydroxylase.     

Knowledge-based planning using pseudo-structures for volumetric modulated arc therapy (VMAT) of postoperative uterine cervical cancer: a multi-institutional study

BackgroundThe aim of this study was to investigate the performance of the RapidPlan (RP ) using models registered pseudostructures, and to determine how many structures are required for automatic optimization of volumetric modulated arc therapy (VMAT) for postoperative uterine cervical cancer.Materials and methodsPseudo-structures around the PTV were retrospectively contoured for patients who had completed treatment at five institutions. For 22 common patients, plans were generated with a single optimization for models with two (RP_2), four (RP_4), and five (RP_5) registered structures, and the dosimetric parameters of these models were compared with a clinical plan with several optimizations.ResultsMost dosimetric parameters showed no major differences between each RP model. In particular, the rectum D_max, V_50Gy, and V_40Gy with RP_2, RP_4, and RP_5 were not significantly different, and were lower than those of the clinical plan. The average proportions of plans achieving acceptable criteria for dosimetric parameters were close to 100% for all models. Using RP_2, the average time for the VMAT planning was reduced by 88 minutes compared with the clinical plan.ConclusionThe RapidPlan model with two registered pseudo-structures could generate clinically acceptable plans while saving time.