共查询到20条相似文献,搜索用时 22 毫秒
1.
P. Angelini R. Pagiotti B. Granetti 《World journal of microbiology & biotechnology》2008,24(2):197-202
Melaleuca alternifolia (tea tree) essential oil was investigated for its “in vitro” ability to control Trichoderma harzianum, a fungal contaminant that causes extensive losses in the cultivation of Pleurotus species. The antifungal activity of M. alternifolia essential oil and antagonist activities between Pleurotus species against three T. harzianum strains were studied in dual-culture experiments on an agar-based medium in which different concentrations of essential oil
were incorporated. M. alternifolia essential oil at a concentration of 0.625 μL/mL, inhibited T. harzianum mycelial growth by 5.9–9.0%, depending on the strain. At the same concentrations P. ferulae and P. nebrodensis stimulated mycelial growth by 5.2–8.1%. All strains of T. harzianum were antagonistic to the Pleurotus species in the control. When essential oil was added to the substrate cultural, the antagonistic activity of T. harzianum against the Pleurotus species was weak (0.0625 μL of essential oil) or non-existent (0.125 μL of essential oil). M. alternifolia essential oil could be an alternative to the synthetic chemicals that are currently used to prevent and control T. harzianum in mushroom cultivation. 相似文献
2.
Mercedes Verdeguer M. Amparo Blzquez Herminio Boira 《Biochemical Systematics and Ecology》2009,37(4):362-369
The essential oil composition of Lantana camara, Eucalyptus camaldulensis and Eriocephalus africanus was analyzed by means of GC and GC–MS and bioassayed in order to determine their activity against Amaranthus hybridus and Portulaca oleracea. E. camaldulensis essential oil, with spathulenol as the main compound, was the most effective, completely inhibiting germination and seedling growth on both weeds. The essential oil of E. africanus, rich in artemisia ketone, showed activity similar to that of E. camaldulensis on A. hybridus, but it was not so effective against P. oleracea, and L. camara essential oil, with high percentages in sesquiterpene hydrocarbons, also showed higher phytotoxic activity against A. hybridus, inhibiting its germination and seedling length; however, it showed no effect against P. oleracea germination, whereas was effective in significantly reducing its seedling growth at all concentrations assayed. The results suggest the possible use of these essential oils as natural herbicides. 相似文献
3.
野油菜黄单胞菌中烯脂酰ACP还原酶的功能鉴定 总被引:1,自引:0,他引:1
烯脂酰ACP还原酶是细菌脂肪酸合成的关键酶之一.本研究通过生物信息学分析发现,野油菜黄单胞菌Xanthomonas campestris(Xcc)8004基因组中XC_0119(Xccfab V)注释为反-2-烯脂酰Co A还原酶基因.但其编码产物与铜绿假单胞菌的烯脂酰ACP还原酶Fab V具有较高的同源性,并含有相同的催化活性中心Tyr-(Xaa)8-Lys序列.用携带Xccfab V的质粒载体互补大肠杆菌fab I温度敏感突变株JP1111,转化子能在42℃生长,表明Xccfab V能遗传互补大肠杆菌fab I突变.体外重建脂肪酸合成反应表明,Xcc Fab V能催化不同链长的烯脂酰ACP还原为脂酰ACP,且催化活性不受三氯森抑制.遗传学研究表明,Xccfab V是必需基因,不能获得Xccfab V基因敲除突变株.将携带大肠杆菌fab I的外源质粒导入野生菌后,可敲除染色体上的fab V基因,获得的替换突变株生长特性和脂肪酸组成未发生显著变化,但替换突变株对三氯森敏感.上述结果证实,野油菜黄单胞菌fab V是必需基因,编码烯脂酰ACP还原酶,参与脂肪酸从头合成反应,且Fab V是Xcc对三氯森耐受的根本原因. 相似文献
4.
A. Cristina Figueiredo M. Salomé S. Pais Johannes J. C. Scheffer 《Plant Cell, Tissue and Organ Culture》1995,40(2):113-118
The composition of the essential oil isolated from Achillea millefolium L. ssp. millefolium cell suspension cultures was analysed by GC and GC-MS. The yield of the oil obtained by hydrodistillation or a simultaneous distillation -extraction of these cultures, harvested at days 8–10 (end of exponential phase), was 0.001 % (w/w). The analysis of the volatiles showed the presence of thirteen components; monoterpenes amounted to 5%, sesquiterpene hydrocarbons attained 40%, while eugenol, demethoxyencecalin and two unidentified compounds amounted to 45% of the total oil. Several methods were tested in an attempt to increase the essential oil production by the cultures: growth on solid medium, growth in light, use of a different culture medium, elicitation with cellulase or yeast extract, and growth in a two-phase system. Of the different methods tested, the growth in B5+ medium with Miglyol 812 led to the highest essential oil yield (0.002%, w/w), and resulted in a more diverse oil composition. 相似文献
5.
Selectable marker recycling in the chloroplast 总被引:22,自引:0,他引:22
N. Fischer O. Stampacchia K. Redding J. -D. Rochaix 《Molecular & general genetics : MGG》1996,251(3):373-380
The bacterial geneaadA is an important and widely used selectable marker for manipulation of the chloroplast genome through biolistic transformation. Because no other such marker is available, two strategies for recycling of theaadA cassette have been developed. One utilizes homologous recombination between two direct repeats flanking theaadA cassette to allow its loss under non-selective growth conditions. A second strategy is to perform co-transformation with a plasmid containing a modified, non-essential chloroplast gene and another plasmid in which theaadA cassette disrupts a chloroplast gene known to be essential for survival. Under selective growth conditions the first mutation can be transferred to all chloroplast DNA copies whereas theaadA insertion remains heteroplasmic. Loss of the selectable marker can be achieved subsequently by growing the cells on non-selective media. In both cases it is possible to reuse theaadA cassette for the stepwise disruption or mutagenesis of any gene in the same strain. 相似文献
6.
The aim of this study was to find an alternative to synthetic fungicides currently used in the control of devastating oomycete
pathogen Phytophthora infestans, causal agent of late blight disease of tomato. Antifungal activities of essential oils obtained from aerial parts of aromatic
plants such as oregano (Origanum syriacum var. bevanii), thyme (Thymbra spicata subsp. spicata), lavender (Lavandula stoechas subsp. stoechas), rosemary (Rosmarinus officinalis), fennel (Foeniculum vulgare), and laurel (Laurus nobilis), were investigated against P. infestans. Both contact and volatile phase effects of different concentrations of the essential oils used were determined by using
two in vitro methods. Chemical compositions of the essential oils were also determined by GC-MS analysis. Major compounds found in essential
oils of thyme, oregano, rosemary, lavender, fennel and laurel were carvacrol (37.9%), carvacrol (79.8), borneol (20.4%), camphor
(20.2%), anethole (82.8%) and 1,8-cineole (35.5%), respectively. All essential oils were found to inhibit the growth of P. infestans in a dose-dependent manner. Volatile phase effect of oregano and thyme oils at 0.3 μg/ml air was found to completely inhibit the growth of P. infestans. Complete growth inhibition of pathogen by essential oil of fennel, rosemary, lavender and laurel was, however, observed
at 0.4–2.0 μg/ml air concentrations. For the determination of the contact phase effects of the tested essential oils, oregano, thyme and
fennel oils at 6.4 μg/ml were found to inhibit the growth of P. infestans completely. Essential oils of rosemary, lavender and laurel were inhibitory at relatively higher concentrations (12.8, 25.6,
51.2 μg/ml respectively). Volatile phase effects of essential oils were consistently found to be more effective on fungal growth
than contact phase effect. Sporangial production was also inhibited by the essential oil tested. Light and scanning electron
microscopic (SEM) observation on pathogen hyphae, exposed to both volatile and contact phase of oil, revealed considerable
morphological alterations in hyphae such as cytoplasmic coagulation, vacuolations, hyphal shrivelling and protoplast leakage. 相似文献
7.
Kapoor Rupam Giri Bhoopander Mukerji Krishan G. 《World journal of microbiology & biotechnology》2002,18(5):459-463
The effects of application of two arbuscular mycorrhizal (AM) fungi Glomus macrocarpum and G. fasciculatum on shoot biomass and concentration of essential oil in Anethum graveolens L. and Trachyspermum ammi (Linn.) Sprague fruits were evaluated. Results revealed significant variation in effectiveness of the two AM fungal species. AM fungal inoculation in general improved the growth of the plants. On mycorrhization, the concentration of essential oil increased up to 90% in dill and 72% in carum over their respective controls. Glomus macrocarpum was more effective than G. fasciculatum in enhancing the oil concentration. The constituents of the essential oils were characterized by gas liquid chromatography. The levels of limonene and carvone were enhanced in essential oil obtained from G. macrocarpum-inoculated dill plants, while G. fasciculatum inoculation resulted in a higher level of thymol in carum. 相似文献
8.
Summary Leaves ofChenopodium ambrosioides exhibited strong fungitoxicity against the mycelial growth ofRhizoctonia solani causing damping off diseases of some seedlings. Minimum inhibitory concentration of the fungitoxic constituent isolated in form of essential oil, was found to be 1000 ppm at which it was fungicidal in nature. It exhibited broad range of antifungal activity and did not show any phytotoxicity on the germination and seedling growth ofPhaseolus aureus. 相似文献
9.
Synthetic lethal mutants have been previously isolated in fission yeast Schizosaccharomyces pombe, which genetically interact with spmex67, in order to identify the genes involved in mRNA export. The nup211 gene was isolated by complementation of the growth defect in one of the synthetic lethal mutants, SLMex2, under synthetic
lethal condition. We showed that Nup211, fission yeast homolog of Mlpl/Mlp2/Tpr, is essential for vegetative growth and Nup211-GFP
proteins expressed at endogenous level are localized mainly in nuclear periphery. The accumulation of poly(A)+ RNA in the nucleus is exhibited when expression of nup211 is repressed or over-expressed. These results suggest that the Nup211 protein plays a pivotal role of mRNA export in fission
yeast. 相似文献
10.
为探明杭白芷(Angelica dahurica var.formosana)根中分泌道发生方式、分布及其挥发油转运积累特征,该研究利用光镜及透射电子显微镜技术观察分泌道发生过程及挥发油转运特征,结合组织化学定位确定挥发油的主要积累部位。结果表明:杭白芷根中分泌道由中柱鞘细胞最先发生,次生结构中分泌道主要分布在韧皮部和皮层中;挥发油的合成不仅与分泌细胞中质体及细胞质有关,而且还与周围细胞关系密切;分泌细胞内高尔基体和内质网丰富,可能先通过形成小泡参与转运,再经由细胞壁向腔道内转移;相邻分泌细胞靠近角隅处的细胞壁分泌活动活跃,腔道内积累大量电子致密物质;成熟分泌道中分泌细胞及其腔道内积累大量油滴,因此挥发油主要积累场所为分泌细胞及其腔道。该研究明确了杭白芷根中分泌道的发生方式、分布及其挥发油积累部位,揭示了分泌道发育过程中挥发油的转运积累特征,为进一步阐明分泌组织生长发育与有效成分积累关系提供了理论依据。 相似文献
11.
Artemia cysts produced in inoculated salt ponds in the Philippines, Thailand and India, were analyzed in comparison with the parental strains used for the inoculations. Cyst hatching efficiency, hatching rate and color changed significantly after inoculation, whereas the cyst's diameters, nauplius survival and nauplius growth remained fairly constant. The nutritional value of theArtemia nauplii was determined in a standard culture test withMysidopsis bahia juveniles as test animals. Production results were compared with the fatty acid profiles of theArtemia nauplii. Low levels of the essential fatty acid 20:53 in one of the produced cyst batches were probably caused by inadequate food conditions in the pond and resulted in poorer growth of theMysidopsis juveniles. Based on the results of this study a distinction is made between essential and nonessential strain selection-criteria forArtemia inoculations and transplantations. 相似文献
12.
Mahdi Yahyazadeh Reza Omidbaigi Rasoul Zare Hossein Taheri 《World journal of microbiology & biotechnology》2008,24(8):1445-1450
The antifungal action of four essential oils of Foeniculum vulgare (fennel), Thymus vulgaris (thyme), Eugenia caryophyllata (Clove) and Salvia officinalis (sage) was tested in vitro against Penicillium digitatum Sacc. Direct contact and vapour phase were used to test the antifungal activity of these essential oils against P. digitatum that is responsible for green mould rot of citrus fruits. The vapour phase and direct contact of clove and thyme essential
oils exhibited the strongest toxicity and totally inhibited the mycelial growth of the test fungus. Thyme and clove essential
oils completely inhibited P. digitatum growth either when added into the medium 600 μl l−1 or by their volatiles with 24 μl per 8 cm diameter Petri dish. In in vitro mycelial growth assay showed fungistatic and fungicidal
activity by clove and thyme essential oils. Sage and fennel oils did not show any inhibitory activity on this fungus. Scanning
electron microscopy (SEM) was done to study the mode of action of clove oil in P. digitatum and it was observed that treatment with the oil leads to large alterations in hyphal morphology. 相似文献
13.
The opportunistic Candida albicans yeast strain ATCC 10261 grows at 37 °C and gives germ tubes after 3 h on corn meal agar and blood plasma. It produces chlamydospores and assimilates sucrose, dextrose, galactose, maltose, trehalose and xylose among the tested carbon sources. Other growth characters were also investigated. The agar diffusion cut plug technique revealed that 200 l of Foeniculum vulgare Miller (fennel), Mentha piperita L. (peppermint) and Citrus limon (lemon) essential oils showed inhibitory actions. Fumigation test of the three essential oils had complete inhibition on the growth. The essential oil of Eucalyptus occidentalis End1 (eucalyptus, eucalypt) had no influence on C. albicans growth by the two tests. Meanwhile, methanol extracts of both leaves and male cones of the conifer Thuja orientalis (eastern thuya) had an inhibitory influence on the growth by two tests (cut plug and filter paper disc assay). In comparative tests the antibiotics mycostatin and dermatin had an inhibitory activity on C. albicans at the concentrations of 50–80 g per hole. Crude methanol extract of leaves of eastern thuya (10–80 g/ml) reduced C. albicans growth and intercellular protein nitrogen on liquid media. 相似文献
14.
The embryo essential gene EMB506 plays a crucial role in the transition of the Arabidopsis embryo from radial symmetry to bilateral symmetry just prior to the early heart stage of development. In addition to influencing
embryo development EMB506 also affects chloroplast biogenesis. To further investigate the role of EMB506 gene expression in Arabidopsis we have generated green fluorescent protein (GFP) marked emb506 mosaic sectors at temporally defined stages during embryogenesis and additionally during various stages of vegetative growth,
in otherwise phenotypically wild-type plants. We confirm the essential requirement for EMB506 gene expression in chloroplast biogenesis as reflected by the decreased chlorophyll content in emb506 mosaic sectors. We also show that the influence of EMB506 gene expression as it impinges on chloroplast biogenesis is first relevant at an intermediate stage in embryogenesis and
that the role of EMB506 gene expression in chloroplast biogenesis is distinct from the essential role of EMB506 gene expression during early embryo development. By inducing emb506 mosaicism after the essential requirement for EMB506 gene expression in embryogenesis and also during vegetative growth we reveal that EMB506 gene expression additionally is required for correct cotyledon-, true leaf- and cauline leaf margin development. The strategy
that we describe can be tailored to the mosaic analysis of any cloned EMB gene for which a corresponding mutant exists and can be applied to the mosaic analysis of mutant lethal genes in general. 相似文献
15.
Palmarosa (Cymbopogon martinii var. motia) was found to be associated with a vesicular-arbuscular mycorrhizal (VAM) fungus, Glomus aggregatum. Glasshouse experiments showed that inoculation of palmarosa with G. aggregatum caused a two-fold growth and three-fold biomass production as compared to non-mycorrhizal plants. These findings indicate the potential use of VAM-fungi for improving the production of this essential oil bearing plant.CIMAP Publication No. 879.CIMAP Publication No. 879. 相似文献
16.
Buildings with poor indoor air quality (IAQ) frequently have many areas with surface fungal contamination. Studies have demonstrated
that certain fungal genera (e.g., Cladosporium, Penicillium, and Stachybotrys) are able to grow on building materials such as wallpaper, drywall, and ceiling tiles, particularly after water damage has
occurred. Due to the increasing awareness of sick building syndrome (SBS), it has become essential to identify building materials
that prevent the interior growth of fungi. The objective of this study was to identify building materials that would not support
the growth of certain fungal genera, regardless of whether an external food source was made available. The growth of three
fungal genera (Cladosporium, Penicillium, and Stachybotrys) was evaluated on cellulose-containing ceiling tile (CCT) and inorganic ceiling tile (ICT). Both types of ceiling tile were
exposed to environmental conditions which can occur inside a building. Our results show that ICT did not support the growth
of these three fungal genera while CCT did. Our data demonstrate that ICT could serve as an ideal replacement for CCT.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Machado M Dinis AM Salgueiro L Custódio JB Cavaleiro C Sousa MC 《Experimental parasitology》2011,(4):732-739
The present work evaluates the anti-Giardia activity of Syzygium aromaticum and its major compound eugenol. The effects were evaluated on parasite growth, adherence, viability and ultrastructure. S. aromaticum essential oil (IC50 = 134 μg/ml) and eugenol (IC50 = 101 μg/ml) inhibited the growth of G. lamblia. The essential oil inhibited trophozoites adherence since the first hour of incubation and was able to kill almost 50% of the parasites population in a time dependent manner. The eugenol inhibited G. lamblia trophozoites adherence since the third hour and not induce cell lyses. The main morphological alterations were modifications on the cell shape, presence of precipitates in the cytoplasm, autophagic vesicles, internalization of flagella and ventral disc, membrane blebs, and intracellular and nuclear clearing. Taken together, our findings lead us to propose that eugenol was responsible for the anti-giardial activity of the S. aromaticum essential oil and both have potential for use as therapeutic agents against giardiasis. 相似文献
18.
Ishikura M Hagiwara K Takishita K Haga M Iwai K Maruyama T 《Marine biotechnology (New York, N.Y.)》2004,6(4):378-385
Recent molecular biological studies have revealed that some photosymbiotic invertebrates dwelling in coral reefs host several genetically different dinoflagellates, Symbiodinium species, as symbionts. However, little is known about the difference in physiologic characteristics among these symbionts living in a single host, because some Symbiodinium strains are difficult to culture in vitro. To isolate some of these Symbiodinium strains, we have developed an agar culture medium plate containing antibiotics and a giant clam tissue homogenate. Using-this medium we isolated two new Symbiodinium strains from two molluscan hosts, Tridacna crocea and Pteraeolidia ianthina, each of which hosted two different Symbiodinium strains belonging to Symbiodinium C and D, respectively. The tissue homogenate was essential for the growth of Symbiodinium D. Although it was not essential for the growth of Symbiodinium C, it did stimulate the initial growth. For the isolation of some Symbiodinium strains, isolation medium containing host homogenate is effective. 相似文献
19.
Chromium and its compounds may cause disturbance in the nutrient level of the plants. Iron, manganese, copper, and zinc are
essential nutrient elements and required for balanced growth and development of plants, but chromium uptake sometimes disturbed
their concentration in plants. Therefore, in the present paper, an effort has been made to observe the effect of different
levels of Cr on nutrient uptake of Phyllanthus amarus and Solanum nigrum, the medicinally important plants of indigenous systems of medicine having hepatoprotective and diuretic properties. The
study revealed that Cr causes significant changes in nutrient uptake as compared to control plants. Besides, Cr-treated plants
showed growth depression and decrease in fresh and dry weight too. With the increase in Cr supply, accumulation of Cr in roots
was increased significantly. Concentration of manganese and zinc was also increased. However, copper concentration in both
the plants seemed less affected by Cr. 相似文献
20.
Two-dimensional electrophoretic analysis of the regulation of SOS proteins in three ssb mutants 总被引:3,自引:0,他引:3
Ben F. Johnson 《Archives of microbiology》1984,138(2):106-112
A previously undescribed mutation in the ssb gene, which codes for a major single strand DNA binding protein essential for DNA repelication, was mapped on the Escherichia coli Chromosome. Three ssb mutants were analyzed under parallel physiological conditions for the induction of SOS proteins (products of recA, uvrA, and an unknown gene), the production of mutants, the induction of lambda prophage, and sensitivity to DNA damaging agents. Two-dimensional electrophoretic techniques were used to quantitate changes in the rate of synthesis of proteins. The previously unpublished position of the uvrA gene-product in the two-dimensional matrix of E. coli proteins was described. These ssb strains exhibited varying sensitivities to ultraviolet irradiation and methylmethane sulfonate that correlated with the rate of constitutive synthesis of SOS proteins, spontaneous commitment to virulent growth of lambda lysogens, and elevation of endogenous mutation rates.Dedicated to the memory of Roger Y. Stanier: to his fascination for diverse microbial lifeforms that catalyzed curiosity in his associates, to his intellectual aura that elicited deep respect, to his pursuit of scientific truth that promoted the highest research ethics, to his friendly nature that encouraged my growth as a scientist and enkindled my love for Roger 相似文献