4种珍稀食用菌水提物的抗氧化活性研究

用DPPH自由基清除法、羟基自由基清除法和超氧阴离子自由基清除法对4种珍稀食用菌灵芝、云芝、茶树菇、松茸的水提物进行抗氧化活性评价,为更好评价其抗氧化活性,以维生素C作为阳性对照。实验结果显示：4种食用菌水提物具有不同程度的抗氧化活性。云芝对DPPH自由基的清除能力最强,其IC₅₀值为1.46 mg/mL,维生素C清除DPPH自由基的IC₅₀为0.046 mg/mL;茶树菇对清除羟基自由基的清除能力最强,其IC₅₀值为1.41 mg/mL,云芝和松茸也有较强清除羟自由基能力,其IC₅₀值分别为1.56、1.57 mg/mL,三者的清除能力均明显优于阳性对照样品,维生素C清除羟自由基的IC₅₀为2.41 mg/mL;灵芝和云芝有较强清除超氧阴离子自由基能力,其IC₅₀值分别为124.48、138.28 mg/mL。     

Effect of the Microbial Feed Additive Saccharomyces cerevisiae CNCM I-1077 on Protein and Peptide Degrading Activities of Rumen Bacteria Grown In Vitro

We investigated the potential of the ruminant feed additive Saccharomyces cerevisiae CNCM I-1077 on protein and peptide degrading activities of the rumen bacterial species Prevotella albensis M384, Streptococcus bovis 20480, and Butyrivibrio fibrisolvens 3071 grown in vitro. Alive or heat-killed yeast cells were added to bacterial cultures in a complex casein–glucose medium. After incubation of the cultures at 39°C under O₂-free CO₂, peptidase activities were determined in the absence or in the presence of yeasts. Protease activities were detected after PAGE in gelatin-copolymerized gels. In co-incubations of bacteria and live S. cerevisiae I-1077, proteinase activities were reduced compared to the activities in the bacterial monocultures. Measurement of peptidase activities and microbial enumerations in the co-incubations suggested that live yeasts and bacteria interacted in a competitive way, leading to a decrease in peptidase activities. The mechanism responsible for such an effect could be mainly a competition for substrate utilization, but the release of small competitive peptides by the yeast cells is also likely to be implicated.     

Activities of de-N-glycosylation are ubiquitously found in tomato plant

Activities of two de-N-glycosylation enzymes, PNGase (peptide N ⁴(N-acetyl-glucosaminyl)asparagine amidase) and ENGase (endo N-acetyl-β-D-glucosaminidase), involved in the release of N-glycans from N-glycoproteins, were monitored in several organs of tomato plants (Lycopersicon esculentum, Mill., cv. Dombito) with a fluorescence-HPLC procedure using a resofurin-labelled N-glycopeptide substrate. PNGase and ENGase activities were detected in every organ assayed but with quantitative differences. The highest activities were found in the youngest parts of the plant, i.e. apical buds, flowers and leaf blades. PNGase activities were consistently higher than ENGase activities (three-fold in average). Both de-N-glycosylation activities were associated with high levels of proteins and protease activities. During fruit growth and ripening, these three parameters decreased notably. The ubiquitous detection of these enzyme activities in the different organs is probably associated with the previously characterized unconjugated N-glycans in tomato. The possible role of PNGase and ENGase degradation products (i.e. unconjugated N-glycans) are discussed in relation with their biological functions in plant development.     

5种相思树和尾巨桉人工林土壤养分和酶活性特征

为揭示固氮树种土壤养分转化的酶学机制,对固氮树种[厚荚相思(Acacia crassicarpa)、黑木相思(A. melanoxylon)、卷荚相思(A.cincinnata)、大叶相思(A.auriculiformis)和马占相思(A.mangium)]及非固氮树种尾巨桉(Eucalyptusurophylla×E.grandis)人工林的土壤养分含量、酶活性及其相关性进行研究。结果表明,相思林40～60cm土层的pH均高于尾巨桉林;5种相思林土壤各土层的TP、TK含量均低于尾巨桉林,而20～40 cm土层的TC、TN含量均高于尾巨桉林,黑木相思林和马占相思林各土层的有效养分均显著高于尾巨桉林(P0.05)。0～10 cm土层中,相思林的土壤酸性磷酸酶和纤维素酶活性均高于尾巨桉林,大叶相思林的土壤脲酶、蔗糖酶、纤维素酶和芳基硫酸酯酶活性显著高于尾巨桉林(P0.05),卷荚相思林的土壤脲酶、纤维素酶、几丁质酶和淀粉酶活性显著高于尾巨桉林(P0.05)。相关分析结果表明,土壤脲酶、蔗糖酶和几丁质酶活性与AP显著负相关(P0.05),蔗糖酶和纤维素酶活性与NH4+-N显著负相关(P 0.05),脲酶、纤维素酶、芳基硫酸酯酶与土壤TK显著负相关(P0.05),几丁质酶活性与TN含量呈显著正相关(P0.05),土壤淀粉酶活性与NH4+-N呈显著正相关(P 0.05),过氧化氢酶活性与土壤TK含量呈显著正相关。可见,与尾巨桉人工林相比,在我国南方退化山地引种相思树可提高土壤关键酶的活性,对土壤有效养分具有明显改良作用,有利于退化地土壤的生态修复及人工林长期生产力的维持。     

石油污染土壤中不同人工林木根际丛枝菌根真菌与球囊霉素的研究

以陕西延长县石油污染区常见的13种人工种植林木为材料,测定了各人工种植林木根际丛枝菌根(AM)真菌发育状况、污染土壤的理化性质、土壤酶活性和球囊霉素含量,探讨AM真菌在石油污染土壤生态修复中的作用。结果表明,13种林木均能形成AM,其定殖率平均为63.2%,孢子密度平均为1.93个.g-1干土,其中受污染程度最低的柠条AM真菌定殖率和孢子密度最高,分别为91.6%和4.73个.g-1干土;毛白杨、狼牙刺和刺槐的根际土壤养分(有机碳、碱解氮、速效磷)含量相对较高;各种人工种植林木的根际土壤球囊霉素含量、多酚氧化酶和过氧化氢酶活性随根际土壤石油烃污染浓度的增加而明显升高,其中刺槐、狼牙刺和酸枣根际土壤的过氧化氢酶和多酚氧化酶活性都较高,同时这3种林木的球囊霉素含量也较高。因此,林木根际土壤球囊霉素含量、多酚氧化酶和过氧化氢酶活性可以作为石油污染的敏感指标。     

Vacuolating,lethal, collagenase and clostripain activities of six reference ATCC <Emphasis Type="Italic">Clostridium histolyticum</Emphasis> strains

We have previously demonstrated that C. histolyticum reference strain ATCC 19401 produces not only lethal factor but also hitherto unrecognized vacuolating toxin. The aim of this study was to compare vacuolating and lethal activities of six reference C. histolyticum strains (ATCC 6282, 8034, 17859, 17860, 19401 and 25770) and to determine whether production of vacuolating toxin is strain-dependent and how the amounts of both toxins produced by the same strain are related to each other and also to protease, collagenase and clostripain activities. All strains produced vacuolating and lethal toxins as well as collagenase, clostripain and proteases, but with different yield. Strain ATCC 19401 demonstrated considerable vacuolating and lethal activities and low activity of collagenase, clostripain and proteases. In other strains such relationship was not evident. Positive correlations were observed in collagenase and clostripain activities of all studied C. histolyticum strains (r = 0.71). Positive correlations were detected also in vacuolating activities of studied strains and clostripain (r = 0.62) and collagenase (r = 0.87) production, and this effect was statistically significant (P < 0.05). Negative non-significant correlations were detected: (a) in lethal activities of studied strains and clostripain, or collagenase activities, (b) in vacuolating activities and protease production.     

A survey of proteases in edible mushrooms with synthetic peptides as substrates

The protease activities in six edible mushrooms were surveyed using synthetic fluorogenic substrates that have different specificities for each protease group. The activity was determined by measuring the fluorogenic intensity of the 7-amino-4-methylcoumarin (AMC) liberated by an enzyme. Various types of activities were found in all mushrooms, and their activities depended largely on the mushroom species, but also on the pH and localization. Flammulina velutipes and Pleurotus eryngii had the widest and highest proteolytic activities among the six mushrooms examined. The proteasome-like protease activities were generally much higher than those of other proteases. High caspase activities, which occur during apoptosis in cells, were detected in two mushrooms, F. velutipes and Hypsizigus marmoreus. The pH optima of the proteolytic activities were largely divided into two groups, acidic pH 5–6 for caspases and neutral to alkaline (pH 6.5–11) for the others. In F. velutipes, higher proteolytic activity was observed in the basement of the stem than in the cap and stem. Purification and characterization of protease were also carried out to identify a protease from Grifola frondosa using t-butyloxycarbonyl-Leu-Arg-Arg-4-methylcoumaryl-7-amide (Boc-LRR-MCA) as the substrate.     

Characterization of the oxaloacetate decarboxylase and pyruvate kinase-like activities of Saccharomyces cerevisiae and Anaerobiospirillum succiniciproducens phosphoenolpyruvate carboxykinases

Two members of the ATP-dependent class of phosphoenolpyruvate carboxykinases (PEPCKs) (Saccharomyces cerevisiae and Anaerobiospirillum succiniciproducens) have been comparatively studied with regard to their oxaloacetate (OAA) decarboxylase and pyruvate kinase-like activities. The pyruvate kinase-like activities were dependent on the presence of Mn²⁺; at the same concentrations Mg²⁺ was not effective. These activities were synergistically activated by a combination of both metal ions. V _max for these activities in A. succiniciproducens and S. cerevisiae PEPCKs was 0.13% and 1.2% that of the principal reaction, respectively. The OAA decarboxylase activity was nucleotide independent and, with decreasing order of effectiveness, these activities were supported by Mn²⁺ and Mg²⁺. AMP is an activator of these reactions. V _max for the OAA decarboxylase activities in A. succiniciproducens and S. cerevisiae PEPCKs was 4% and 0.2% that of the PEP-forming reaction, respectively.     

Superoxide-scavenging and Tyrosinase-inhibitory Activities of the Extracts of Some Chinese Medicines

The superoxide-scavenging and the tyrosinase-inhibitory activities of 28 kinds of plants used as Chinese medicines were evaluated. Methanol/water extracts were used for the screening tests, and for those which represented high activities, other kinds of extracts were also studied. The extracts of Mallotus japonicus Muell. Arg. scavenged superoxide strongly; the half-inhibiting concentration (IC₅₀) of its 50% methanol/water extract was 10.57 μg of dried material in 1 ml of reaction mixture. The extracts of Fntillaria thunbergii Miq., Carthamus tinctorius L., and Prunus persica (L.) Batsch had strong tyrosinase-inhibitory activities, and the extracts of Scutellariu baicalensis Georgi represented both kinds of activities. These facts suggested that Chinese medicines may be a treasure house of chemical compounds that have the superoxide-scavenging and the tyrosinase-inhibitory activities.     

Occurrence of laccase and tyrosinase in fungi of agaricales and comparative study of laccase fromRussula delica andRussula pseudodelica

The activities of laccase and tyrosinase, that is, oxidation activities ofp-phenylenediamine andp-cresol in the fruiting bodies of species belonging to various genera of Agaricales were examined. Among 40 genera examined, appreciable laccase activities were observed in fungi belonging toLepista, Omphalina, Agaricus, Russula andLactarius. High typosinase activities were found in many species ofHygrophorus, Laccaria, Lepista, Melanoleuca, Collybia, Marasmius, Amanita, Agaricus, Inocybe, Pholiota, Russula andLactarius. Species of other genera exmained did not show either enzyme activities to any extent. FromRussula delica andRussula pseudodelica, laccases were extracted and purified, and some characteristics were compared. Molecular weight and absorption spectra of these laccases were very similar to each other, but they were different in electrophoretical mobilities and substrate specificity. This work was presented at the Annual Meeting of the Bot. Soc Japan in Oct. 1970 at Matsuyama.     

Bacteriolytic activities of the free-living soil amoebae,Acanthamoeba castellanii,Acanthamoeba polyphaga andHartmannella vermiformis

Bacteriolytic activities of axenically grown free-living soil amoebaeAcanthamoeba castellanii, Acanthamoeba polyphaga andHartmannella vermiformis towards various Gram-positive and Gram-negative bacteria were determined. A spectrophotometric assay revealed that the specific bacteriolytic activities of bothAcanthamoeba species were higher as those of the threeHartmannella strains.Bacillus megaterium, Bacillus subtilis, Chromatium vinosum, Micrococcus luteus andPseudomonas fluorescens were more easily lysed than the other bacteria tested.Agrobacterium tumefaciens, Klebsiella aerogenes andSerratia marcescens were hardly affected at all by the amoebal bacteriolytic activities. Among the Gram-negative bacteria we observed differences in lysis sensitivity while the Gram-positive bacteria tested were sensitive to lysis. Isoelectric focusing (IEF) gel-electrophoresis in the pH range 3–10 was performed to separate the bacteriolytic isoenzymes of amoebae. Bacteriolytic patterns were shown by using an activity assay in which lysis bands were formed in the agar/bacteria gel-overlay. The activity assay revealed remarkable differences in typical banding patterns for bacteriolytic activities among amoebae. Distinct differences between typical pI points of bacteriolytic activities inAcanthamoeba andHartmannella were shown. Bacteriolytic activities ofHartmannella were more pronounced and observed in the isoelectric points (pI) range of 4.0–9.3 while forAcanthamoeba the range was pI 4.5–8.9.Abbreviations IEF isoelectric focusing - PAA-IEF polyacrylamide-isoelectric focusing - CCAP culture collection of algae and protozoa - AS amoeba saline medium - pI isoelectric points     

Synthesis of β‐Ketoamide Curcumin Analogs for Anti‐Diabetic and AGEs Inhibitory Activities

Two different series of novel β‐ketoamide curcumin analogs enriched in biological activities have been synthesized. The synthesized compounds were screened for their in vitro anti‐diabetic and AGEs inhibitory activities and exhibited potent to good anti‐diabetic and AGEs inhibitory activities. The molecular docking study was also performed with the α‐amylase enzyme.     

Cell-Cycle-Specific Activity of Cyclic Nucleotide Phosphodiesterase In Physarum polycephalum

The cell-cycle-related activities of the cAMP- and cGMP-dependent phosphodiesterases of Physarum polycephalum were assayed. the activities of plasmodial homogenate and of selected subcellular fractions were measured. the results suggested the presence of both cAMP- and cGMP-dependent phosphodiesterase in the isolated nuclei of P. polycephalum. In addition, they reveal that the cAMP- and cGMP-dependent phosphodiesterase activities of the subcellular fractions fluctuate throughout the cell cycle. the whole-cell homogenates exhibit no cell-cycle-related changes in the presence of 5 × 10^-4 m cGMP. Kinetic data suggest the presence of multiple phosphodiesterase activities in the homogenate and its particulate fractions for the cGMP-dependent enzyme. Multiple cAMP activities are also suggested for the particulate fractions. the K_m values indicate that the substrate affinities of the phosphodiesterases from P. polycephalum are similar to those found previously in mammalian systems.     

Endoglucanase activities and growth of marine‐derived fungi isolated from the sponge Haliclona simulans

Aims: The conversion of cheap cellulosic biomass to more easily fermentable sugars requires the use of costly cellulases. We have isolated a series of marine sponge‐derived fungi and screened these for cellulolytic activity to determine the potential of this unique environmental niche as a source of novel cellulase activities. Methods and Results: Fungi were isolated from the marine sponge Haliclona simulans. Phylogenetic analysis of these and other fungi previously isolated from H. simulans showed fungi from three phyla with very few duplicate species. Cellulase activities were determined using plate‐based assays using different media and sea water concentrations while extracellular cellulase activities were determined using 3,5‐dinitrosalicylic acid (DNSA)‐based assays. Total and specific cellulase activities were determined using a range of incubation temperatures and compared to those for the cellulase overproducing mutant Hypocrea jecorina QM9414. Several of the strains assayed produced total or relative endoglucanase activities that were higher than H. jecorina, particularly at lower reaction temperatures. Conclusions: Marine sponges harbour diverse fungal species and these fungi are a good source of endoglucanase activities. Analysis of the extracellular endoglucanase activities revealed that some of the marine‐derived fungi produced high endoglucanase activities that were especially active at lower temperatures. Significance and Impact of the Study: Marine‐derived fungi associated with coastal marine sponges are a novel source of highly active endoglucanases with significant activity at low temperatures and could be a source of novel cellulase activities.     

类球红细菌类胡萝卜素抗氧化活性研究

研究了研磨法、超声波法、酸溶辅助超声波法和菌体浓度对类球红细菌类胡萝卜素抗氧化活性的影响。结果表明,不同提取方法和固液比条件下,类球红细菌类胡萝卜素均具有清除DPPH自由基能力、抗脂质过氧化能力和还原能力。酸溶辅助超声波法提取的类胡萝卜素产率最高、抗氧化活性最好。类球红细菌类胡萝卜素具有一定的抗氧化活性,其抗氧化活性随菌体浓度的增加而增加。     

Phytochemical composition and antioxidant activities of different aerial parts extracts of Ferula communis L.

The present study aimed to assess antioxidant activities of three organs (flower, fruit, and stem) extracts of Tunisian Ferula (F.) communis. Various experimental models were used to characterize the antioxidant activities in vitro as well as on ROS-induced fluorescence using dichlorofluorescein technique from phorbol myristate acetate (PMA)-stimulated human myeloid cell line HL-60. Results showed that the antioxidant activities varied considerably with organs. Thus, flower exhibited higher DPPH-scavenging ability, reducing and chelating power than stem and fruit. Also, antioxidant capacities using ORAC method and a cell-based assay showed that fruit and stem exhibited statistically similar antioxidant activities. Moreover, F. communis contains high amounts of flavonoids with various health benefits attributed to their antioxidant potential. Likewise, to obtain biologically relevant information, the antioxidant activities of the extracts were evaluated on cellular models implicating the antioxidant activities; this test generally showed that F. communis flower extracts have the highest antioxidant capacities correlated to the highest total phenolic content. The identification of phenolic compounds in F. communis extracts using RP-HPLC revealed that resorcinol, ferulic, and syringic acids together with coumarin were the major molecules.     

Identification of thermostable β-xylosidase activities produced by <Emphasis Type="Italic">Aspergillus brasiliensis</Emphasis> and <Emphasis Type="Italic">Aspergillus niger</Emphasis>

Twenty Aspergillus strains were evaluated for production of extracellular cellulolytic and xylanolytic activities. Aspergillus brasiliensis, A. niger and A. japonicus produced the highest xylanase activities with the A. brasiliensis and A. niger strains producing thermostable β-xylosidases. The β-xylosidase activities of the A. brasiliensis and A. niger strains had similar temperature and pH optima at 75°C and pH 5 and retained 62% and 99%, respectively, of these activities over 1 h at 60°C. At 75°C, these values were 38 and 44%, respectively. Whereas A. niger is a well known enzyme producer, this is the first report of xylanase and thermostable β-xylosidase production from the newly identified, non-ochratoxin-producing species A. brasiliensis.     

Synthesis and Structure−Activity Relationship of Omaezallene Derivatives

Omaezallene derivatives (nor‐bromoallene, nor‐bromodiene, and bromoenynes) were successfully synthesized. Their antifouling activity and toxicity to the cypris larvae of the barnacle Amphibalanus amphitrite and ecotoxicity to the marine crustacean Tigriopus japonicus were studied. It was revealed that the two side chains of omaezallene were essential to its antifouling activity because the activities of nor‐bromoallene and nor‐bromodiene were significantly diminished. The bromoenyne was found to exhibit potent antifouling activities comparable to omaezallene with low toxicity and ecotoxicity. Preparation of bromoenyne framework is much easier than that of bromodiene moiety in omaezallene. Based on the antifouling activities of the bromoenynes, the synthesis of fluorescent probes and evaluation of their biological activities were also carried out.     

Intrinsic GUS-like activities in seed plants

Fifty-two plant species, covering some Gymnosperms and all the key groups of Angiosperms, were chosen for surveying their intrinsic beta-glucuronidase-like activities. Histochemical (overnight incubation) and qualitative fluorometric (24 h incubation) assays indicated that, with few exceptions, such activities were detected in certain part(s) of the fruit walls, seed coats, endosperms or, especially, the embryos of the tested plants. Most of such activities in the excised immature embryos of soybean and string bean disappeared after one to a few days' in vitro culturing. Such activities in the intact mature seeds of these two species diminished also during germination process. The vegetative organs of seedlings/mature plants usually lack such activities. The enzyme(s) responsible for such activities was antigenically dissimilar to E. coli beta-glucuronidase.Abbreviations B5 basal medium described by Gamborg et al. (1968) - GUS beta- glucuronidase - MUG 4-methyl umbelliferyl glucuronide - X-Glu 5-bromo-4-chloro-3-indolyl glucuronide     

Rise in human activities on the mudflats and Brent Geese (Branta bernicla) wintering distribution in relation to Zostera spp. beds: a 30-year study

Human activities may restrict access of wintering birds to their food resources, but habitat destruction and fragmentation may interact with disturbance to reduce carrying capacity. We analysed the abundance and distribution of wintering Brent Geese (Branta bernicla) in a major French wintering site from 1970 to 2000, when they experienced increases in human foreshore activities. We used mixed-effects models to test whether spatial extent of two Zostera species, Z. noltii and Z. marina, influenced the distribution of Brent Geese. The number of geese increased significantly with the area of both Zostera species beds. However, the relationship changed in the period after the increase in human activities. More specifically, fragmentation of the most accessible food resource, Z. noltii, negatively affected Brent Goose distribution. This fragmentation was in turn increased by human activities and reduced by the protection of Z. noltii (by banning human access). This implies that direct disturbance, although not excluded, might not have been the major cause of changes in Brent Goose distribution, but rather the effects of human activities on food resources. Thus, our results show that establishment of resource protection areas are efficient as conservation measures, and they underline the need for studies of impacts of human activities on resources, in addition to disturbance effects.