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41.
We investigated the spatial and temporal distribution of xylans in the cell walls of differentiating earlywood tracheids of
Cryptomeria japonica using two different types of monoclonal antibodies (LM10 and LM11) combined with immunomicroscopy. Xylans were first deposited
in the corner of the S1 layer in the early stages of S1 formation in tracheids. Cell corner middle lamella also showed strong xylan labeling from the early stage of cell wall formation.
During secondary cell wall formation, the innermost layer and the boundary between the S1 and S2 layers (S1/S2 region) showed weaker labeling than other parts of the cell wall. However, mature tracheids had an almost uniform distribution
of xylans throughout the entire cell wall. Xylan localization labeled with LM10 antibody was stronger in the outer S2 layer than in the inner layer, whereas xylans labeled with LM11 antibody were almost uniformly distributed in the S2 layer. In addition, the LM10 antibody showed almost no xylan labeling in the S1/S2 region, whereas the LM11 antibody revealed strong xylan labeling in the S1/S2 region. These findings suggest that structurally different types of xylans may be deposited in the tracheid cell wall depending
on the developmental stage of, or location in, the cell wall. Our study also indicates that deposition of xylans in the early
stages of tracheid cell wall formation may be spatially consistent with the early stage of lignin deposition in the tracheid
cell wall. 相似文献
42.
Hayashi A Aoyagi H Kinjyo K Yoshimura T Tanaka H 《Applied microbiology and biotechnology》2007,75(6):1437-1446
Screening method of microorganisms that utilized the symbiotic association between insect (Nasutitermes takasagoensis: Nt) and intestinal microorganisms was developed. The existence of desired microorganisms that grew by degrading difficult-to-degrade
materials in the gut was detected using survivability of Nt as an indicator. The desired microorganisms were isolated from
the survived Nt. It was thought that guts of Nt behave as continuous culture systems whereby microorganisms that cannot degrade
diet components are washed out, whereas those that can degrade it are retained and concentrated in the gut. About 60% of Nt
fed with phenol artificial diet (PAD) died within 7 days, while 4% of termites survived for 9 days. The structure of intestinal
microorganisms of the survived Nt fed with PAD differed from the bacterial communities obtained from enrichment culture (which
contained phenol) of wood-feeding Nt. Relatively high colonies (650-times) were detected in the gut of Nt fed on phenol artificial
diet compared with those obtained when Nt was fed on wood. Seven denaturing gradient gel electrophoresis (DGGE) bands were
detected from gut of wood-feeding Nt, whereas 11 DGGE-bands were detected from that of phenol-feeding Nt. Out of 11 DGGE-bands,
5 of them were sequenced, and bacterial species including phenol-degrading bacteria were identified. 相似文献
43.
44.
Daisuke Sano Takatomo Ohta Arata Nakamura Toyoko Nakagomi Osamu Nakagomi Satoshi Okabe 《Applied and environmental microbiology》2015,81(8):2819-2826
The inability of molecular detection methods to distinguish disinfected virions from infectious ones has hampered the assessment of infectivity for enteric viruses caused by disinfection practices. In the present study, the reduction of infectivity of murine norovirus S7-PP3 and mengovirus vMC0, surrogates of human noroviruses and enteroviruses, respectively, caused by free-chlorine treatment was characterized culture independently by detecting carbonyl groups on viral capsid protein. The amount of carbonyls on viral capsid protein was evaluated by the proportion of biotinylated virions trapped by avidin-immobilized gel (percent adsorbed). This culture-independent approach demonstrated that the percent adsorbed was significantly correlated with the logarithm of the infectious titer of tested viruses. Taken together with the results of previous reports, the result obtained in this study indicates that the amount of carbonyls on viral capsid protein of four important families of waterborne pathogenic viruses, Astroviridae, Reoviridae, Caliciviridae, and Picornaviridae, is increased in proportion to the received oxidative stress of free chlorine. There was also a significant correlation between the percent adsorbed and the logarithm of the ratio of genome copy number to PFU, which enables estimation of the infectious titer of a subject virus by measuring values of the total genome copy number and the percent adsorbed. The proposed method is applicable when the validation of a 4-log reduction of viruses, a requirement in U.S. EPA guidelines for virus removal from water, is needed along with clear evidence of the oxidation of virus particles with chlorine-based disinfectants. 相似文献
45.
Yano S Suyotha W Honda A Takagi K Rattanakit-Chandet N Wakayama M Tachiki T 《Bioscience, biotechnology, and biochemistry》2011,75(2):299-304
Chitinase I (CHI1) of Bacillus circulans KA-304 forms protoplasts from Schizophyllum commune mycelia when the enzyme is combined with α-1,3-glucanase of B. circulans KA-304. CHI1 consists of an N-terminal unknown region and a C-terminal catalytic region classified into the glycoside hydrolase family-19 type. An N-terminal region-truncated mutant of CHI 1 (CatCHI1), which was expressed in Escherichia coli Rosetta-gami B (DE3), lost colloidal chitin- and powder chitin-binding activities. The colloidal chitin- and the powder chitin-hydrolyzing activities of CatCHI1 were lower than those of CHI1, and CatCHI1 was not effective in forming the protoplast. A fusion protein of the N-terminal region of CHI1 and green fluorescent protein (Nterm-GFP) was expressed in E. coli, and the fusion protein was adsorbed to colloidal chitin, powder chitin, and chitosan. Fluorescence microscopy analysis showed that Nterm-GFP bound to the S. commune cell-wall. 相似文献
46.
Synthesis of microbial signaling molecules and their stereochemistry-activity relationships 总被引:1,自引:0,他引:1
Yajima A 《Bioscience, biotechnology, and biochemistry》2011,75(8):1418-1429
Microbial signaling molecules such as autoinducers and microbial hormones play important roles in intercellular communication in microorganisms. Information transfer between the individual cells of a microorganism is one of the most important biological events among them. Researchers often suffer from extremely low levels of microbial signaling molecule contents, which prevent them from understanding chemistry and biology of intercellular communication in microorganisms. Chemical synthesis is a powerful tool to obtain sufficient amounts of sample and to clarify the structure of a molecule. This review focuses on the synthesis and stereochemistry-bioactivity relationships of five microbial signaling molecules, Vibrio cholerae autoinducer-1 (CAI-1), AI-2 precursor (DPD), an acylhomoserine lactone from Rhizobium leguminosarum (small bacteriocin), a diffusible extracellular factor of Xanthomondas campestris pv. campestris, and Phytophthora mating hormone α1. 相似文献
47.
Ojika M Molli SD Kanazawa H Yajima A Toda K Nukada T Mao H Murata R Asano T Qi J Sakagami Y 《Nature chemical biology》2011,7(9):591-593
The heterothallic species of the agricultural pest Phytophthora use mating hormones α1 and α2 to regulate their sexual reproduction. Here we describe the absolute stereostructure of the second mating hormone α2 as defined by spectroscopic analysis and total synthesis. We have uncovered not only the interspecies universality of α hormones but also the pathway by which α2 is biosynthesized from phytol by A2-mating type strains and metabolized to α1 by A1 strains. 相似文献
48.
49.
Ohno F Watanabe J Sekihara H Hirabayashi T Arata S Kikuyama S Shioda S Nakaya K Nakajo S 《Regulatory peptides》2005,126(1-2):115-122
We have found that pituitary adenylate cyclase-activating polypeptide (PACAP) employed at the physiological concentrations induces the differentiation of mouse neural stem cells into astrocytes. The differentiation process was not affected by cAMP analogues such as dibutylic cAMP (db-cAMP) or 8Br-cAMP or by the specific competitive inhibitor of protein kinase A, Rp-adenosine-3',5'-cyclic monophosphothioate triethylamine salt (Rp-cAMP). Expression of the PACAP receptor (PAC1) in neural stem cells was detected by both RT-PCR and immunoblot using an affinity-purified antibody. The PACAP selective antagonist, PACAP(6-38), had an inhibitory effect on the PACAP-induced differentiation of neural stem cells into astrocytes. These results indicate that PACAP acts on the PAC1 receptor on the plasma membrane of mouse neural stem cells, with the signal then transmitted intracellularly via a PAC1-coupled G protein, does not involve Gs. This signaling mechanism may thus play a crucial role in the differentiation of neural stem cells into astrocytes. 相似文献
50.
Prado CM Leick-Maldonado EA Arata V Kasahara DI Martins MA Tibério IF 《American journal of physiology. Lung cellular and molecular physiology》2005,288(4):L741-L748
In the present study we evaluated the role of neurokinins in the modulation of inducible nitric oxide synthase (iNOS) inflammatory cell expression in guinea pigs with chronic allergic airway inflammation. In addition, we studied the acute effects of nitric oxide inhibition on this response. Animals were anesthetized and pretreated with capsaicin (50 mg/kg sc) or vehicle 10 days before receiving aerosolized ovalbumin or normal saline twice weekly for 4 wk. Animals were then anesthetized, mechanically ventilated, given normal saline or N(G)-nitro-l-arginine methyl ester (l-NAME, 50 mg/kg ic), and challenged with ovalbumin. Prechallenge exhaled NO increased in ovalbumin-exposed guinea pigs (P < 0.05 compared with controls), and capsaicin reduced this response (P < 0.001). Compared with animals inhaled with normal saline, ovalbumin-exposed animals presented increases in respiratory system resistance and elastance and numbers of total mononuclear cells and eosinophils, including those expressing iNOS (P < 0.001). Capsaicin reduced all these responses (P < 0.05) except for iNOS expression in eosinophils. Treatment with l-NAME increased postantigen challenge elastance and restored both resistance and elastance previously attenuated by capsaicin treatment. Isolated l-NAME administration also reduced total eosinophils and mononuclear cells, as well as those cells expressing iNOS (P < 0.05 compared with ovalbumin alone). Because l-NAME treatment restored lung mechanical alterations previously attenuated by capsaicin, NO and neurokinins may interact in controlling airway tone. In this experimental model, NO and neurokinins modulate eosinophil and lymphocyte infiltration in the airways. 相似文献