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1.
《Bioscience, biotechnology, and biochemistry》2013,77(7):1404-1406
A new lipoxygenase inhibitor, 6'-hydroxyoxosorbicillinol (1, C14H16O6), was identified from a culture of Penicillium sp. A known compound, oxosorbicillinol (2, C14H16O5), was also isolated. Compound 1 showed an approximately 10 times greater inhibitory effect on soybean lipoxygenase (IC50, 16 µM) than 2 (IC50, 150 µM), and also showed prostaglandin D2 (PGD2) and leucotriene B4 (LTB4) release suppression activity (IC50, 10 µM for PGD2 and 100 µM for LTB4). 相似文献
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Sadao Sakamura Jiro Ito Ryutaro Sakai 《Bioscience, biotechnology, and biochemistry》2013,77(1):153-155
Ethionine-resistant mutants derived from Corynebacterium glutamicum KY 9276 (Thr?) were found to accumulate l-methionine in culture media. One of the mutants, ER-107-4, which produced 250 μg/ml of l-methionine was subjected to further mutagenesis to obtain better l-methionine producers. l-Methionine production increased stepwise by successive endowing such markers as selenomethionine, 1,2,4-triazole, trifluoromethionine and methionine hydroxamate resistance. Thus, a mutant multi-resistant to ethionine, selenomethionine and methionine hydroxamate, ESLMR-724, produced 2 mg/ml of l-methionine in a medium containing 10% glucose.Increase of l-methionine production was accompanied by increased levels and reduced repressibility of methionine-forming enzymes. The levels of methionine enzymes in ESLMR-724 increased to 2.5~4.2 fold of those in KY9276, In addition, homoserine-O-trans-acetylase and cystathionine γ-synthase which were strongly repressed by l-methionine in KY 9276 were stimulated by exogenous l-methionine in ESLMR-724. Implications of these results were discussed in relation to the productivity of l-methionine and the regulation of l-methionine biosynthesis. 相似文献
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A specimen of the machaeridianLepidocoleus cf.ulrichi described herein focuses attention on taxonomical difficulties with extremely dorso-ventrally elongated sclerites found in
some lepidocoleid taxa.Lepidocoleus ulrichi
Withers, 1926 andLepidocoleus sigmoideus
Withers, 1926 exhibit very similar appearances and prove indistinguishable based onWithers 1926 criteria. The key to separating taxa as similar as these may instead lie in the most juvenile stages of growth. 相似文献
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凤仙花属(Impatiens L.)10种植物花粉形态的扫描电镜观察 总被引:1,自引:0,他引:1
利用扫描电镜观察了10种凤仙花属(Impatiens L.)植物的花粉形态。结果表明:本属花粉为单粒花粉,呈长圆形至长矩圆形,大小为20.3~46.7 μm,具角萌发孔,网状纹饰,网眼明显;根据花粉网状纹饰中网眼内是否具颗粒状突起可将其分为2类:(1)网眼内无或近无颗粒状突起,黄金凤(I. siculifer)和婺源凤仙花(I. wuyuanensis)的花粉纹饰属于这一类型;(2)网眼内有明显颗粒状突起,其余8个种的花粉纹饰均属于该类型。研究表明,花粉特征,特别是花粉粒网状纹饰中网眼内有无颗粒状突起及颗粒状突起的形态等特征,在凤仙花属内常具种水平上的可见变异,因而可作为种类划分的依据,它们在分类学上的价值应予以关注。 相似文献
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Sarracenia purpurea L. plants were studiedin seven bogsalong the eastern seaboard of the United States fromNew Jersey to Georgia. Water sampled from 225 leaveswas found to contain several invertebrates. A singlebdelliod rotifer, a form of Habrotrocha cf. rosaDonner very similar to that described by Bateman(1987) in S. purpurea in western Newfoundland,was identified in 70% of the leaves. Investigationsare in progress to examine the possibility that thisstrong association indicates H. cf. rosa isspecific to S. purpurea. 相似文献
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The pollination mechanism of most genera of the Podocarpaceae involves inverted ovules, a pollination drop and bisaccate pollen grains. Saccate grains have sometimes been referred to as 'non-wettable' due to their buoyant properties, while non-saccate pollen grains have been described as 'wettable'. The hydrodynamic properties of saccate pollen grains of seven podocarp species in five genera, Dacrydium Sol. ex G. Forst., Dacrycarpus (Endl.) de Laub., Manoao Molloy, Podocarpus L'Hér. ex Pers. and Prumnopitys Phil. have been tested in water, together with saccate and non-saccate pollen of four other conifer genera, Cedrus Trew (Pinaceae), Cephalotaxus Siebold & Zucc. ex Endl. (Cephalotaxaceae), Cupressus L. (Cupressaceae) and Phyllocladus Rich. ex Mirb. (Phyllocladaceae), and spores of three fern species and one lycopod species. All four spore types studied were non-wettable, whereas the bisaccate and trisaccate pollen types, like all other conifer pollen types, were wettable, enabling the grains to cross the surface tension barrier of water. Once past this barrier, grain behaviour was governed by presence or absence of sacci. Non-saccate and vestigially saccate grains sank, whereas saccate grains behaved like air bubbles, floating up to the highest point. In addition, the grains were observed to float in water with sacci uppermost, consistent with the suggestion that distally placed sacci serve to orientate the germinal furrow of the pollen grain towards the nucellus of an inverted ovule. Observations of pollen grains in the pollen chambers of naturally pollinated Prumnopitvs ovules confirmed this. The combination of buoyancy and wettability in saccate pollen has implications for the efficiency of the typical podocarp pollination mechanism. 相似文献
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Effects of different pulse fed-batch methods on production of the anti-cancer compound 1403C by marine mangrove endophytic fungus Halorosellinia sp. (No. 1403) in a 5-L bioreactor were investigated. Since high glucose concentrations improved mycelial growth but inhibited 1403C production, the cultures were pulse fed with glucose solutions to keep the residual glucose lower than 4 g/L but higher than 0.5 g/L during rapid growth phase (0-50 h). In this way, a maximum dry biomass, 1403C production and yield coefficient (Y1403C/X) of up to 4.5 g/L, 2.64 g/L and 0.59 g/g dry cell weight, respectively were achieved. These values are 22.7%, 98.0% and 61.4%, respectively higher than those obtained with batch cultures. This strategy is valuable for fermentation scale-up of Halorosellinia sp. (No. 1403) for 1403C production, and might also be applicable to other marine fungi cultures. 相似文献
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The large-scale distribution patterns of the estuarine spionid polychaetes Marenzelleria cf. viridis, Pygospio elegans, and Streblospio shrubsoli were studied in the Pomeranian Bay (southern Baltic Sea) at 20 stations in April 1993 and their relationship with hydrographic factors and sediment composition investigated. The densities of M. cf. viridis and S. shrubsoli decreased rapidly with increasing distance offshore. A corresponding decrease in phytoplankton concentration offshore is suggested as the main cause for the observed spatial patterns. P. elegans was more evenly distributed. At 10 selected stations further samples were collected between April 1993 and July 1996 to study the response of abundance and biomass of the three polychaetes to changes in environmental conditions and to investigate interspecific interactions within the macrofauna. Salinity, pelagic food supply, and sediment parameters did not change. At three of these stations redox potential of the sediment and macrofauna composition were affected by an unusual hypoxic/anoxic event in July/August 1994. All three spionid species were able to survive moderate seasonal hypoxic conditions, but died after exposure to severe anoxia. Special attention was focused on the re-establishment of the spionids. The rate with which M. cf. viridis and P. elegans re-colonised defaunated stations varied between a few weeks and two years. These differences in rate of re-establishment were attributed to the distance from undisturbed recruitment areas, and to the severity of the oxygen deficiency. Increasing densities of P. elegans and S. shrubsoli after the hypoxic event coincided with a reduced abundance of the bivalve Mya arenaria, suggesting a negative interspecific interaction. 相似文献
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George I. Oduor Gilberto J. de Moraes John S. Yaninek Leo P.S. van der Geest 《Experimental & applied acarology》1995,19(10):571-579
The effect of temperature, humidity and photoperiod on the development of Neozygites cf. floridana (Weiser and Muma) in the cassava green mite, Mononychellus tanajoa (Bondar) was studied in the laboratory. Dead infected mites began to appear 2.5 days after inoculation. At 33 and 28°C peak mortalities were higher and occurred earlier (after 2.5 days), than at 23 and 18°C. Mean LT50 (time for half the infected mites to die) decreased with increasing temperature as follows: 3.9, 3.0, 2.9 and 2.5 days at 18, 23, 28 and 33°C, respectively. When placed under conditions of high relative humidity for a period of 24 h, the percentage of dead infected mites from which the fungus sporulated was highest at 28°C (51.4%) and lowest at 33°C (6.5%). The development of the fungus inside the mite was not significantly affected by ambient humidity or photoperiod. No significant interactions between tested factors were found. 相似文献
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Disanthus cercidifolius Maxim.var.longipes H.T.Chang,a plant species that only occurs in a few counties in Hunan,Jiangxi and Zhejiang Provinces and with a relatively small number of individuals,is ranked as a second Class endangered species for conservation in China.We have studied the effect of pollen and resources available to female reproduction,and the reproductive mechanism of "excess flowers with low fruit set" in Disanthus cercidifolius Maxim.var.longipes H.T.Chang was discussed.Results are as follows:Pollen from different sources has significant effects on fruit set and seed set of Disanthus cercidifolius Maxim.var.longipes H.T.Chang.The pollen source rather than pollen numbers significantly affected reproduction of this species.In wild populations,producing one fruit needs about 54.8 flowers,and one satiation seed needs about 6.60 flowers or 83.19 ovules.After fertilizing,which was propitious to flower development,the abortion rate of flower buds was decreasing,but the flowering rate was increasing.The fruit set and seed set was also significantly increasing,while abortion rate of fruit was significantly decreasing.With the increasing percentages of cutting leaves,the fruit set decreased,but the abortion rate of fruit shows no significant differentiation among treatments.After cutting branches that were puny,broken and insectinfested branches,the flower number seemed to be decreasing,but the fruit set and seed set all increased significantly.After removing some flowers,the fruit set was calculated with respect to the number of flowers remaining after the treatment increased with increasing of percentages of flower removal,whereas fruit set calculated with respect to the initial number of flowers remained constant,and the mean weights of per fi'uit and per seed all decreased significantly.Sufficient spatial or temporal heterogeneities in nutrient levels might allow limitation of seed set by resources and pollen in a natural population,while supplying resources may indirectly affect pollination by increasing attraction of the flowers to pollinators.There were very low fruit and seed sets in natural populations ofDisanthus cercidifolius Maxim.var.longipes H.T.Chang.Different factors may have interacted to effect a low fruit set.A joint adoption of the "selection abortion hypothesis","ovary reserve hypothesis" and "male function hypothesis" seems to be the most likely explanation for the reproductive strategy of"excess flowers with few fruit sets" in Disanthus cercidifolius Maxim.var.longipes H.T.Chang. 相似文献
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The main purpose of this study was to investigate the effects of benzo(a)pyrene (BaP) on seabass (Dicentrarchus labrax) juveniles using parameters at different levels of biological organization. Liver antioxidant status, BaP biotransformation and accumulation, growth, and behavior were determined in juveniles after 28 d exposure to BaP (1–16 μ g/l). Liver ethoxyresorufin O-deethylase increased in seabass exposed to 1–8 μ g/l of BaP. Liver glutathione S-transferases and catalase activities were significantly increased at 4 and 8 μ g/l, but a slight decrease was observed at the highest concentrations tested. Bile BaP metabolites were significantly different from the control group at 1 and 16 μ g/l BaP. Liver BaP metabolites and lipid peroxidation significantly increased at 8 and 16 μ g/l BaP. These results suggest that BaP metabolites' accumulation induces oxidative damage in seabass liver. Body weight and length increase were significantly reduced in fish exposed to BaP, with LOECs of 16 and 4 μ g/l, respectively. Food intake and swimming velocity were significantly decreased after exposure to BaP, with LOEC values of 16 and 8 μ g/l, respectively. Results suggest that at concentrations of BaP equal or higher than 8 μ g/l, the detoxification capacity decreases, an accumulation of liver BaP metabolites occurs causing lipid peroxidation, affecting growth and swimming capability of fish. 相似文献
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目的:合成并表征一种属于植物生长激素的席夫碱类化合物.方法:由5-硝基水杨醛和3,5-二羟基苯甲酰肼在甲醇溶液中反应得到N′-(5-硝基-2-羟基苯亚甲基)-3,5-二羟基苯甲酰肼.结果:用单晶X-射线衍射法测得其结构并表征,同时通过抗菌实验证明其在一定浓度下具有明显的抗菌活性.结论:这种席夫碱类化合物在某种程度上具有明显的抗菌活性. 相似文献
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Subbiah Poopathi K. Anup Kumar N. Arunachalam B. K. Tyagi Vaithilingam Sekar 《Biocontrol Science and Technology》2003,13(8):743-748
The efficacy of Bacillus sphaericus and B. thuringiensis israelensis produced on a new potato-based culture medium as well as the conventional culture medium of Luria Bertani was compared against Culex quinquefasciatus in the field. After sporulation, the spores/crystals were harvested and used. The bacterial samples controlled the larvae and pupae for three weeks. Mortality due to the bacterial toxins produced from the new culture medium was very high and comparable to that produced using conventional medium. But the cost for cultivating these bacteria using potato extract was much lower as compared with that of the conventional medium. 相似文献
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(±)-(2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid was metabolized by Cercospora cruenta, which has the ability to produce (+)-abscisic acid (ABA), to give (±)-(2Z,4E)-xanthoxin acid, (±)-(2Z,4E)-5′-hydroxy-1′,2′-epoxy-1′,2′-dihydro-β-ionylideneacetic acid, (±)-1′,2′-epoxy-1′,2′-dihydro-β-ionone and trace amounts of ABA. 相似文献
19.
C. J. MARINKELLE 《The Journal of eukaryotic microbiology》1979,26(3):352-353
SYNOPSIS. Trypanosoma (Megatrypanum) megachiropterorum sp. n. from the flying fox, Pteropus tonganus Quoy & Gaimard, from the Kingdom of Tonga, is described. The trypomastigotes measure 32 ± 1.74 (here and below S.D.) (27–37.5) × 3.6 ± 0.23 (3–4.5) μm and has a flagellum averaging in length 6.4 ± 0.92 (4.5–10) μm. Their nuclear index is 1.2 ± 0.16 (0.7–1.6) and their kinetoplastic index equals 6.2 ± 0.32 (5.5–7.1). This is the first report of a member of the subgenus Megatrypanum from bats outside the American and African continents and also the first record of a trypanosome from bats in the Pacific area. 相似文献
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Xiao Yian He Ping Zeng Jianjun Li Xiaohong Hu Wenhai 《Frontiers of Biology in China》2007,2(4):437-442
Disanthus cercidifolius Maxim. var. longipes H. T. Chang, a plant species that only occurs in a few counties in Hunan, Jiangxi and Zhejiang Provinces and with a relatively
small number of individuals, is ranked as a second Class endangered species for conservation in China. We have studied the
effect of pollen and resources available to female reproduction, and the reproductive mechanism of “excess flowers with low
fruit set” in Disanthus cercidifolius Maxim. var. longipes H. T. Chang was discussed. Results are as follows
Pollen from different sources has significant effects on fruit set and seed set of Disanthus cercidifolius Maxim. var. longipes H. T. Chang. The pollen source rather than pollen numbers significantly affected reproduction of this species. In wild populations,
producing one fruit needs about 54.8 flowers, and one satiation seed needs about 6.60 flowers or 83.19 ovules.
After fertilizing, which was propitious to flower development, the abortion rate of flower buds was decreasing, but the flowering
rate was increasing. The fruit set and seed set was also significantly increasing, while abortion rate of fruit was significantly
decreasing. With the increasing percentages of cutting leaves, the fruit set decreased, but the abortion rate of fruit shows
no significant differentiation among treatments. After cutting branches that were puny, broken and insectin-fested branches,
the flower number seemed to be decreasing, but the fruit set and seed set all increased significantly. After removing some
flowers, the fruit set was calculated with respect to the number of flowers remaining after the treatment increased with increasing
of percentages of flower removal, whereas fruit set calculated with respect to the initial number of flowers remained constant,
and the mean weights of per fruit and per seed all decreased significantly.
Sufficient spatial or temporal heterogeneities in nutrient levels might allow limitation of seed set by resources and pollen
in a natural population, while supplying resources may indirectly affect pollination by increasing attraction of the flowers
to pollinators. There were very low fruit and seed sets in natural populations of Disanthus cercidifolius Maxim. var. longipes H. T. Chang. Different factors may have interacted to effect a low fruit set. A joint adoption of the “selection abortion hypothesis”, “ovary reserve hypothesis” and “male function hypothesis” seems to be the most likely explanation for the reproductive strategy of “excess flowers with few fruit sets” in Disanthus cercidifolius Maxim. var. longipes H. T. Chang.
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Translated from Acta Ecologica Sinica, 2006, 26(2): 496–502 [译自: 生态学报] 相似文献