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51.
Thienodolin, a new plant growth-regulating substance, was isolated from the fermentation broth of a streptomycete strain identified as Streptomyces albogriseolus.The active principle was extracted with ethyl acetate and purified by silica gel column chromatography and preparative HPLC. The substance showed growth promoting activity with 1.2 × 10?6–1.2 × 10?5 M treatment to rice seedlings, and inhibitory activity with 4.0 × 10?5 M treatment. 相似文献
52.
Fausto Almeida Aline Sardinha-Silva Thiago Aparecido da Silva André Moreira Pessoni Camila Figueiredo Pinzan Ana Claudia Paiva Alegre-Maller Nerry Tatiana Cecílio Nilmar Silvio Moretti André Ricardo Lima Damásio Wellington Ramos Pedersoli José Roberto Mineo Roberto Nascimento Silva Maria Cristina Roque-Barreira 《PloS one》2015,10(12)
Toxoplasma gondii is an obligate intracellular protozoan parasite found worldwide that is able to chronically infect almost all vertebrate species, especially birds and mammalians. Chitinases are essential to various biological processes, and some pathogens rely on chitinases for successful parasitization. Here, we purified and characterized a chitinase from T. gondii. The enzyme, provisionally named Tg_chitinase, has a molecular mass of 13.7 kDa and exhibits a Km of 0.34 mM and a Vmax of 2.64. The optimal environmental conditions for enzymatic function were at pH 4.0 and 50°C. Tg_chitinase was immunolocalized in the cytoplasm of highly virulent T. gondii RH strain tachyzoites, mainly at the apical extremity. Tg_chitinase induced macrophage activation as manifested by the production of high levels of pro-inflammatory cytokines, a pathogenic hallmark of T. gondii infection. In conclusion, to our knowledge, we describe for the first time a chitinase of T. gondii tachyzoites and provide evidence that this enzyme might influence the pathogenesis of T. gondii infection. 相似文献
53.
Spore germination of Ceratocystis fimbriata was studied in termsof host-parasite specificity. The sweet potato, coffee and cacaostrains of Ceratocystis fimbriata germinated well in a fractionof sweet potato root water extract which had been passed througha column of cation exchange resin. The results showed that germinationof these strains was independent of exogenous cations. On theother hand, the prune, oak, taro and almond strains requiredfor germination both the absorbed and unabsorbed fractions ofsweet potato root water extract which were separated from eachother with a cation exchange resin column. Divalent cationssuch as Ca2+ Mg2+, Mn2+ and Zn2+ were identified as the activeprinciples in the absorbed fraction and Ca2+ showed the highestinductive activity for spore germination in the presence ofthe unabsorbed fraction. The active principle(s) in the unabsorbedfraction has not yet been identified. There was no relationshipbetween the Ca2+ and Mg2+ contents of the spores and the requirementof exogenous Ca2+ for germination. Ca2+ appeared to functionas a trigger of spore germination, not as a normal nutrient.These results suggest that the divalent cations such as Ca2+and Mg2+ in sweet potato contribute to the establishment ofhost-parasite specificity of this system. (Received August 10, 1977; ) 相似文献
54.
Identification and characterization of a brilliant yellow pigment produced by Bordetella pertussis 下载免费PDF全文
Keita Odanaka Masato Iwatsuki Tomomitsu Satho Mineo Watanabe 《Microbiology and immunology》2017,61(11):490-496
55.
Euglena gracilis, a unicellular freshwater protist exhibits different photomovement responses, such as phototaxis (oriented movement toward or away from the light source) and photophobic (abrupt turn in response to a rapid increase [step-up] or decrease [step-down] in the light fluence rate) responses. Photoactivated adenylyl cyclase (PAC) has been isolated from whole-cell preparations and identified by RNA interference (RNAi) to be the photoreceptor for step-up photophobic responses but not for step-down photophobic responses (M. Iseki, S. Matsunaga, A. Murakami, K. Ohno, K. Shiga, C. Yoshida, M. Sugai, T. Takahashi, T. Hori, M. Watanabe [2002] Nature 415: 1047-1051). The present study shows that knockdown of PAC by RNAi also effectively suppresses both positive and negative phototaxis, indicating for the first time that PAC or a PAC homolog is also the photoreceptor for photoorientation of wild-type E. gracilis. Recovery from RNAi occurred earlier for step-up photophobic responses than for positive and negative phototaxis. In addition, we investigated several phototaxis mutant strains of E. gracilis with different cytological features regarding the stigma and paraxonemal body (PAB; believed to be the location for the phototaxis photoreceptor) as well as Astasia longa, a close relative of E. gracilis. All of the E. gracilis mutant strains had PAC mRNAs, whereas in A. longa, a different but similar mRNA was found and designated AlPAC. Consistently, all of these strains showed no phototaxis but performed step-up photophobic responses, which were suppressed by RNAi of the PAC mRNA. The fact that some of these strains possess a cytologically altered or no PAB demonstrates that at least in these strains, the PAC photoreceptor responsible for the step-up photophobic responses is not located in the PAB. 相似文献
56.
Wataru Higuchi Mineo Muramatsu Soshi Dohmae Tomomi Takano Hirokazu Isobe Shizuka Yabe Shi Da Tatiana Baranovich Tatsuo Yamamoto 《Microbiology and immunology》2008,52(11):559-563
The use of probiotics such as Lactobacillus in animal feeds has gained popularity in recent years. In this study the 16S rRNA gene sequence of L. acidophilus in two commercial agents which have been used in animal feeds, LAB‐MOS and Ghenisson 22, was determined. Phylogenetic tree analysis revealed that the two agents, strain MNFLM01 in LAB‐MOS and strain GAL‐2 in Ghenisson 22, belonged to L. rhamnosus (a member of the L. casei group) and L. johnsonii (a member of the L. acidophilus group), respectively. Biochemical tests assigned the two as L. rhamnosus and ambiguously as L. acidophilus. The data suggest that 16S rRNA gene sequence analysis provides more accurate identification of Lactobacillus species than biochemical tests and would allow quality assurance of relevant commercial products. The 16S rRNA gene sequences of strains MNFLM01 and GAL‐2 determined in this study have been submitted to the DDBJ/EMBL/GenBank accession numbers under accession numbers AB288235 and AB295648, respectively. 相似文献
57.
Young-Jun Park Kazuhiro Nemoto Tomotaro Nishikawa Kenichi Matsushima Mineo Minami Makoto Kawase 《Molecular breeding : new strategies in plant improvement》2010,25(4):623-635
Waxy strains raised by waxy mutation have been found for three amaranth grains. Three genes encoding waxy protein were isolated from Amaranthus caudatus (Wx-ca), A. cruentus (Wx-cr), and A. hypochondriacus (Wx-hy). Sequence analysis indicated that the Wx-ca, Wx-cr, and Wx-hy genes contained the same exon (13 exons) and intron (12 introns) structure. The lengths of the Wx-ca, Wx-cr, and Wx-hy genes were 3,236, 3,237, and 3,225 bp, respectively. The alignment of the coding sequence of the three Waxy genes showed 12 polymorphic sites, including 11 single nucleotide polymorphisms (SNPs) (in exons 10 and 12 and introns 1, 3, 4, 9, and 11) and 5 deletions or insertions (indels) (in introns 4, 9, and 11). In particular, major polymorphism was detected in 8- and 3-bp indels in intron 4. Moreover, the mutation in the waxy alleles (wx-ca, wx-cr, and wx-hy) of all three species was also isolated and characterized. Comparison of coding sequences of the three Waxy genes and their waxy alleles indicated one base insertion (wx-ca: insert of T base in exon 8) and a base substitution (wx-cr: a G-to-T base substitution in exon 10; wx-hy: a G-to-A base substitution in exon 6), which occurred as internal termination codon in the three Waxy genes, suggesting the involvement of a nonsense or frameshift mutation. Therefore, these different mutations in coding regions were considered to be the cause of the waxy (amylose-free) phenotype. 相似文献
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60.
Masatoshi Mita Ikuo Yasumasu Yoshitaka Nagahama Mineo Saneyoshi 《Development, growth & differentiation》1996,38(4):413-418
The resumption of meiosis in starfish oocytes is induced by 1-methyladenine (1-MeA), which is produced by ovarian foilicle cells under the influence of a gonad-stimulating substance (GSS). It has been reported that the 1-MeA produced is newly synthesized via a process of methylation, rather than being pre-stored within follicle cells or a breakdown product of some 1-MeA-containing substance. The present study examined a possible substrate for 1-MeA biosynthesis stored in follicle cells of the starfish Asterina pectinifera . Analyses using high-performance liquid chromatography indicated a large source of ATP among the adenine-related compounds in these follicle cells. When follicle cells were incubated in seawater in the presence of GSS, 1-MeA production was stimulated significantly. GSS also caused a reduction in intracellular levels of ATP. There was no change in the levels of either ADP or AMP. The amount of ATP consumed under the influence of GSS was similar to the amount of 1-MeA produced. Methionine and selenomethionine enhanced both 1-MeA production and ATP consumption by GSS in follicle cells. In contrast, ethionine and selenoethionine, competitive inhibitors of methionine, inhibited these processes. These results suggest that ATP is a possible substrate in the biosynthesis of 1-MeA by starfish ovarian follicle cells. 相似文献