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31.
In vitro depolymerization of lignin by manganese peroxidase of Phanerochaete chrysosporium 总被引:27,自引:0,他引:27
H Wariishi K Valli M H Gold 《Biochemical and biophysical research communications》1991,176(1):269-275
Homogeneous manganese peroxidase catalyzed the in vitro partial depolymerization of four different 14C-labeled synthetic lignin preparations. Gel permeation profiles demonstrated significant depolymerization of 14C-sidechain-labeled syringyl lignin, a 14C-sidechain-labeled syringyl-guaiacyl copolymer (angiosperm lignin), and depolymerization of 14C-sidechain- and 14C-ring-labeled guaiacyl lignins (gymnosperm lignin). 3,5-Dimethoxy-1,4-benzo-quinone, 3,5-dimethoxy-1,4-hydroquinone, and syringylaldehyde were identified as degradation products of the syringyl and syringyl-guaiacyl lignins. These results suggest that manganese peroxidase plays a significant role in the depolymerization of lignin by Phanerochaete chrysosporium. 相似文献
32.
Andrea M.F. Valli Maria R. Palombo 《Palaeogeography, Palaeoclimatology, Palaeoecology》2008,257(1-2):106-122
In the middle Villafranchian (Late Pliocene) fossil deposit of Saint-Vallier (Drôme, France), the international biochronological reference for the MN17 biozone, deer are the most common species. Two middle-sized taxa, “Metacervoceros” rhenanus [Dubois, E., 1904. On an equivalent of the Cromer Forest Bed in the Netherlands. Koninklijke Akademie van Wetenschappen, 214–222] and Croizetoceros ramosus (Croizet and Jobert, 1828), are particularly abundant. We have performed functional morphology and micro- and mesowear analyses in order to explain if and how the two herbivorous species avoided intra-guild competition. The results of the microwear analysis show a clear difference in the wear pattern of their tooth enamel, demonstrating the two species had different feeding behaviour habits. 相似文献
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Khoa D. Tran Danielle P. Vieira Marco A. Sanchez Jessica Valli Eva Gluenz Scott M. Landfear 《PloS one》2015,10(8)
In a variety of eukaryotes, flagella play important roles both in motility and as sensory organelles that monitor the extracellular environment. In the parasitic protozoan Leishmania mexicana, one glucose transporter isoform, LmxGT1, is targeted selectively to the flagellar membrane where it appears to play a role in glucose sensing. Trafficking of LmxGT1 to the flagellar membrane is dependent upon interaction with the KHARON1 protein that is located at the base of the flagellar axoneme. Remarkably, while Δkharon1 null mutants are viable as insect stage promastigotes, they are unable to survive as amastigotes inside host macrophages. Although Δkharon1 promastigotes enter macrophages and transform into amastigotes, these intracellular parasites are unable to execute cytokinesis and form multinucleate cells before dying. Notably, extracellular axenic amastigotes of Δkharon1 mutants replicate and divide normally, indicating a defect in the mutants that is only exhibited in the intra-macrophage environment. Although the flagella of Δkharon1 amastigotes adhere to the phagolysomal membrane of host macrophages, the morphology of the mutant flagella is often distorted. Additionally, these null mutants are completely avirulent following injection into BALB/c mice, underscoring the critical role of the KHARON1 protein for viability of intracellular amastigotes and disease in the animal model of leishmaniasis. 相似文献
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S. Subbarayudu B. Shankar Naik H. Sunitibala Devi B. S. Bhau P. Shaik Sha Valli Khan 《Plant Systematics and Evolution》2014,300(4):619-632
Zingiber officinale Roscoe, the common ginger, is an invaluable horticultural crop cultivated majorly in China, India, Brazil, Jamaica and Nigeria. Its pungent aromatic rhizome is used all over the world as a spice, culinary herb, condiment, home remedy and medicinal agent. This species does not produce seeds and so is difficult to breed its new genotypes through sexual hybridization. Despite the economic and genetic value, ginger has not been subjected to detailed cytogenetic research, which could lead to a better understanding of its reproduction for future genetic improvement. Therefore, the present work is undertaken for the first time to study microsporogenesis and pollen formation in Z. officinale. Pre-meiotic stages were observed under light microscope using anther squashes and staining by either acetocarmine or carbol fuchsin, whereas, the post meiotic stages were visualized under fluorescence microscope using either isolated microspores or pollen grains stained by 4′, 6′-diamidino-2-phenylindole. The combination of these two different cytological techniques allowed the study of the complete microsporogenesis and pollen formation processes step by step starting from pollen mother cells (PMCs) stage to mature pollen grain. Assessment of meiotic behavior was also performed by evaluating all possible PMCs on each slide and at all stages of meiosis. Cytological analysis revealed that only anthers from flowers of small spikes presented appropriate PMCs to analyze meiotic irregularities. The present paper enriches the database of cytology and pollen viability estimations for supporting sexual hybridization. The present study demonstrated a good relationship between the development stage of microspore and the size of the spike. This basic information will hopefully allow the development of protocol for production of androgenic haploids to accelerate breeding and genetic improvement of ginger. Further, research is under progress for evaluation of several media and other cultural factors to achieve microspore embryogenesis and plant regeneration in this species. 相似文献
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Here we show that low-dose cyclophosphamide (CY), that depends for its therapeutic effectiveness on the immunopotentiating
activity of the drug for T cell-mediated tumor-eradicating immunity, is curative for ~80% of wild-type (WT) mice bearing a
large s.c. MOPC-315 tumor, but only for ~10% of IFN-α/βR−/− mice bearing a large s.c. MOPC-315 tumor. Histopathological examination of the s.c. tumors of such mice on day 4 after the
chemotherapy revealed that the low dose of CY led to accumulation of T lymphocytes in both the WT and the IFN-α/βR−/− mice. However, in the CY treated tumor bearing WT mice the T lymphocytes were present throughout the tumor mass and in direct
contact with tumor cells, but in the CY treated tumor bearing IFN-α/βR−/− mice most of the T lymphocytes remained in blood vessels. In addition to being important for CY-induced transendothelial
migration of T lymphocytes into the tumor mass, we show here that signaling via the IFN-α/βR is also important for CY-induced
control of metastatic tumor progression in the spleen and liver of the tumor bearing mice. Finally, CY cured tumor bearing
WT mice were resistant to a subsequent challenge with MOPC-315 tumor cells, but the few CY cured tumor bearing IFN-α/βR−/− mice were not. Thus, signaling via the IFN-α/βR on host cells in MOPC-315 tumor bearers is important for CY-induced: (a)
transendothelial migration of T lymphocytes into the tumor mass and the eradication of the primary tumor, (b) control of metastatic
tumor progression, and (c) resistance to a subsequent tumor challenge.
This work was supported by Research Grant 03-19 from the American Cancer Society-Illinois Division. 相似文献
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ABSTRACT: INTRODUCTION: Extraskeletal presentation at diagnosis or during the course of multiple myeloma is a rareevent. The prognosis is usually very poor. At the moment there is no agreed gold standard forthe treatment of this presentation. CASE PRESENTATION: A 79-year-old Caucasian woman was treated at our hospital for right atrial myelomalocalization. Our patient showed the following signs and symptoms of congestive heartfailure: dyspnea, hypotension, cyanosis and facial edema. Surgery was not consideredfeasible due to the extent of the disease. Our patient underwent external-beam radiationtherapy using an intensity modulated technique, thus obtaining a persistent completeremission. Our patient has been in continuous complete local remission for 25 months sincethe end of radiotherapy. CONCLUSION: The role of radiotherapy is not defined in multiple myeloma with extraskeletal presentation.Our regimen seems to be effective in controlling the disease in this patient.This case report adds to the existing literature as it describes an unusual presentation of thedisease and a new therapeutic approach to this rare presentation of multiple myeloma. 相似文献
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