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1.
Two fold increase in the yield of glucose and maltose containing exo-polysaccharide (EPS) by Rhizobium sp. was observed during its growth in modified YEMB. EPS production, plant growth promotion activity and root colonization
of Rhizobium sp. studies showed enhanced EPS synthesis, more seed germination and over all improvement in plant growth over control and
R. meliloti treatment. Groundnut seeds bacterized with Rhizobium sp. resulted in 69.75% more root length, 49.51% more shoot height, 13.75% more number of branches and 13.60% more number
of pods over the control and R. meliloti treatment. Bacterization of wheat seeds increased the dry matter yield of roots (1.7-fold), and roots adhering soil (RAS)
(1.5) and shoot mass (1.9-fold). Rhizobium sp. inoculation also increased the population density of EPS-producing bacteria on the rhizoplane. Roots of plants inoculated
with Rhizobium sp. maintained a higher K+/Na+ ratio and K+–Na+ selectivity. 相似文献
2.
During stationary phase of growth under low stress of iron in succinic acid medium, Alcaligenes feacalis BCCM ID 2374 produced microbial iron chelators. Increase in iron concentration supported bacterial growth but suppressed
siderophores production, 1 μM and 2 μM of iron was optimum for maximum siderophore yield, i.e. 354 and 360 μg/ml in untreated
and deferrated medium, respectively. Threshold level of iron, which suppressed siderophores production in A. feacalis BCCM ID 2374, was 20 μM. Ten micromoles and above concentration of CuCl2 and CoCl2, and 20 μM of MgCl2, MgSO4, ZnCl2 and ZnSO4 severely affected siderophores production. 相似文献
3.
Indrajit Dutta Prasenjit Saha Sampa Das 《In vitro cellular & developmental biology. Plant》2008,44(5):401-411
Leaf piece explants of five Brassica juncea (L.) Czern. cultivars were transformed with an Agrobacterium tumefaciens strain EHA105 harboring the plasmid pCAMBIA1301, which contains the β-glucuronidase (uidA) and hygromycin phosphotransferase (hpt) genes under the control of cauliflower mosaic virus 35S (CaMV35S) promoter. Transgenic plants were regenerated on Murashige
and Skoog (MS) medium fortified with 8.87 μM 6-benzylaminopurine, 0.22 μM 2,4-dichlorophenoxyacetic acid, and 20 μM silver
nitrate in the presence of 30 mg/l hygromycin. When co-culture took place in the presence of 100 μM acetosyringone, the efficiency
of stable transformation was found to be approximately 19% in the T
0 generation, with the transgenic plants and their progeny showing constitutive GUS expression in different plant organs. Southern
blot hybridization of uidA and hpt genes confirmed transgene integration within the genome of transformed plants of each cultivar. Inheritance of hpt gene for single copy T-DNA inserts showed a 3:1 pattern of Mendelian segregation in progeny plants through germination of
T
1 seeds on MS medium containing 30 mg/l hygromycin. The protocol described here reports superior transformation efficiency
over previously published protocols and should contribute to enhanced biotechnology applications in B. juncea. 相似文献
4.
Evelin Carlier Marisa Rovera Alberto Rossi Jaume Susana B. Rosas 《World journal of microbiology & biotechnology》2008,24(11):2653-2658
Effects of inoculation of wheat (Triticum aestivum L.) with the rhizobacterium Pseudomonas chlororaphis subsp. aurantiaca strain SR1 (termed SR1) were studied at an experimental field site in Río Cuarto, Argentina. Treatments involved SR1 inoculation
with or without nitrogen/phosphorus fertilization. Inoculation produced a significant increase in plant height and root length
in early growth stages. Inoculation plus fertilization with 40 kg ha−1 urea/30 kg ha−1 diamonic phosphate (“50% dose”) gave a yield increase of 636 kg ha−1 relative to control, and an increase of 472 kg ha−1 relative to fertilization with 80 kg ha−1 urea/60 kg ha−1 phosphate without inoculation. SR1 inoculation without fertilization, compared to control, produced increases of 6% in weight
of 1,000 grains, 13% in number of spikes per plant, and 30% in number of grains per spike. Inoculation plus 50% dose fertilization
also improved these parameters. Results of the study indicate that inoculation of wheat with SR1 improves various growth and
yield parameters, and allows reduced dosage of nitrogen/phosphorus fertilizers in the field. 相似文献
5.
6.
Ingo Schmidt 《Current microbiology》2009,59(2):130-138
The ammonia oxidizers Nitrosomonas europaea and Nitrosomonas eutropha are able to grow chemoorganotrophically under anoxic conditions with pyruvate, lactate, acetate, serine, succinate, α-ketoglutarate,
or fructose as substrate and nitrite as terminal electron acceptor. The growth yield of both bacteria is about 3.5 mg protein
(mmol pyruvate)−1 and the maximum growth rates of N. europaea and N. eutropha are 0.094 d−1 and 0.175 d−1, respectively. In the presence of pyruvate and CO2 about 80% of the incorporated carbon derives from pyruvate and about 20% from CO2. Pyruvate is used as energy and only carbon source in the absence of CO2 (chemoorganoheterotrophic growth). CO2 stimulates the chemoorganotrophic growth of both ammonia oxidizers and the expression of ribulose bisphosphate carboxylase/oxygenase
is down-regulated at increasing CO2 concentration. Ammonium, although required as nitrogen source, is inhibitory for the chemoorganotrophic metabolism of N. europaea and N. eutropha. In the presence of ammonium pyruvate consumption and the expression of the genes aceE, ppc, gltA, odhA, and ppsA (energy conservation) as well as nirK, norB, and nsc (denitrification) are reduced. 相似文献
7.
Hanana H Talarmin H Pennec JP Droguet M Gobin E Marcorelle P Dorange G 《Cytotechnology》2011,63(3):295-305
Heart cells from the clam Ruditapes decussatus were routinely cultured with a high level of reproducibility in sea water based medium. Three cell types attached to the
plastic after 2 days and could be maintained in vitro for at least 1 month: epithelial-like cells, round cells and fibroblastic
cells. Fibroblastic cells were identified as functional cardiomyocytes due to their spontaneous beating, their ultrastructural
characteristics and their reactivity with antibodies against sarcomeric α-actinin, sarcomeric tropomyosin, myosin and troponin
T-C. Patch clamp measurements allowed the identification of ionic currents characteristic of cardiomyocytes: a delayed potassium
current (I
K slow) strongly suppressed (95%) by tetraethylammonium (1 mM), a fast inactivating potassium current (I
K fast) inhibited (50%) by 4 amino-pyridine at 1 mM and, at a lower level (34%) by TEA, a calcium dependent potassium current (I
KCa) activated by strong depolarization. Three inward voltage activated currents were also characterized in some cardiomyocytes:
L-type calcium current (I
Ca) inhibited by verapamil at 5 × 10−4 M, T-type Ca2+ current, rapidly activated and inactivated, and sodium current (I
Na) observed in only a few cells after strong hyperpolarization. These two currents did not seem to be physiologically essential
in the initiation of the beatings of cardiomyocytes. Potassium currents were partially inhibited by tributyltin (TBT) (1 μM)
but not by okadaic acid (two marine pollutants). DNA synthesis was also demonstrated in few cultured cells using BrdU (bromo-2′-deoxyuridine).
Observed effects of okadaic acid and TBT demonstrated that cultured heart cells from clam Ruditapes decussatus can be used as an experimental model in marine toxicology. 相似文献
8.
Yemendzhiev H Gerginova M Krastanov A Stoilova I Alexieva Z 《Journal of industrial microbiology & biotechnology》2008,35(11):1309-1312
Trametes versicolor 1 was shown to grow on phenol as its sole carbon and energy source. The culture growth and degradation ability dependence
on culture medium pH value was observed. The optimal pH value of a liquid Czapek salt medium was 6.5. The investigated strain
utilized completely 0.5 g/l phenol in 6 days. The dynamics of the phenol degradation process was investigated. The process
was characterized by specific growth rate μmax 0.33 h−1, metabolic coefficient k = 4.4, yield coefficient Y
x/s
= 0.23 and rate of degradation Q = 0.506 h−1. The intracellular activities of phenol hydroxylase (0.333 U/mg protein) and cis,cis-muconate lactonizing enzyme (0.41 U/mg protein) were demonstrated for the first time in this fungus. In an attempt to estimate
the occurrence of gene sequences in T. versicolor 1 related to phenol degradation pathway a dot blot analysis with total DNA isolated from this strain was performed. Two synthetic
oligonucleotides were used as hybridizing probes. One of the probes was homologous to the 5′end of phyA gene coding for phenol hydroxylase in Trichosporon cutaneum ATCC 46490. The other probe was created on the basis of cis,cis-muconate lactonizing enzyme coding gene in T. cutaneum ATCC 58094. The results of these investigations showed that T. versicolor 1 may carry genes similar to those of Trichosporon cutaneum capable to degrade phenol. 相似文献
9.
Nitraria retusa and Atriplex halimus (xero-halophytes) plants were grown in the range 0–800 mM NaCl while Medicago arborea (glycophyte) in 0–300 mM NaCl. Salt stress caused a marked decrease in osmotic potential and a significant accumulation of
Na+ and Cl− in leaves of both species. Moderate salinity had a stimulating effect on growth rate, net CO2 assimilation, transpiration and stomatal conductance for the xero-halophytic species. At higher salinities, these physiological
parameters decreased significantly, and their percentages of reduction were higher in A. halimus than in N. retusa whereas, in M. arborea they decreased linearly with salinity. Nitraria retusa PSII photochemistry and carotenoid content were unaffected by salinity, but a reduction in chlorophyll content was observed
at 800 mM NaCl. Similar results were found in A. halimus, but with a decrease in the efficiency of PSII (F′v/F′m) occurred at 800 mM. Conversely, in M. arborea plants we observed a significant reduction in pigment concentrations and chlorophyll fluorescence parameters. The marked
toxic effect of Na+ and/or Cl− observed in M. arborea indicates that salt damage effect could be attributed to ions’ toxicity, and that the reduction in photosynthesis is most
probably due to damages in the photosynthetic apparatus rather than factors affecting stomatal closure. For the two halophyte
species, it appears that there is occurrence of co-limitation of photosynthesis by stomatal and non-stomatal factors. Our
results suggest that both N. retusa and A. halimus show high tolerance to both high salinity and photoinhibition while M. arborea was considered as a slightly salt tolerant species. 相似文献
10.
Fuhong Xie Yapeng Chao Zhiquan Xue Xiuqing Yang Guoqing Zhang Jiaji Shi Shijun Qian 《Journal of industrial microbiology & biotechnology》2009,36(5):739-746
In industry, fosfomycin is mainly prepared via chemical epoxidation of cis-propenylphosphonic acid (cPPA). The conversion yield of fosfomycin is less than 50% in the whole process and a large quantity
of waste is produced. Biotransformation by microorganisms is an alternative method of preparation. This kind of conversion
is more delicate, environmentally friendly, and the conversion yield of fosfomycin would be higher. In this work, an aerobic
bacterium capable of transforming cPPA to fosfomycin was isolated. The organism, designated as strain S101, was identified
as Bacillus simplex by morphological and physiological characteristics as well as by analysis of the gene encoding the 16S rRNA. Fosfomycin was
assayed by two means, bioassay and gas chromatography (GC). Glycerol was a good carbon source for growth and cPPA conversion
of strain S101. When cPPA was used as the sole carbon source, neither growth nor conversion to fosfomycin occurred. The optimum
cPPA concentration in the conversion medium was 2,000 μg ml−1. After 6 days of incubation, the concentration of fosfomycin reached its maximum level (1,838.2 μg ml−1), with a conversion ratio of 81.3%. Air was indispensable for the growth but not for the conversion to fosfomycin. Furthermore,
vanadium ions were found to be essential for the conversion. High concentrations of cPPA had fewer inhibitory effects on the
growth of strain S101. 相似文献
11.
Two inhibitors, aviglycine and propargylglycine, were tested for their ability to suppress methionine synthesis thus inhibit
conidial germination and mycelial growth of Czapek-Dox liquid medium grown Fusarium oxysporum f. sp. luffae
μM. The linear inhibition range for mycelial growth was about 7.6–762.9 μM. Although aviglycine did not completely inhibit both conidial germination and mycelial growth, it showed significant inhibitory
effect at 1.5 μM. The inhibition range for propargylglycine against conidial germination and mycelial growth were from 0.08 to 8841 μM and from 0.8 to 884.1 μM, respectively. Propargylglycine inhibited conidial germination and mycelial growth at a concentration of 8841 μM. The EC50 values of aviglycine were 1 μM for conidial growth and 122 μM for mycelial growth, and the EC50 values of propargylglycine were 47.7 μM for conidial growth and 55.6 μM for mycelial growth. Supplement of methionine released inhibition of aviglycine or propargylglycine to conidial germination.
In addition, a mixture of aviglycine (1.5 μM) and propargylglycine (8841 μM) showed additive inhibitive effect than applied alone on 10 isolates. From these results, both aviglycine and propargylglycine
exhibited inhibitory activity, and suggest that they can provide potential tools to design novel fungicide against fungal
pathogens. 相似文献
12.
Ling Zhao Yongming Bao Jingyun Wang Boshi Liu Lijia An 《World journal of microbiology & biotechnology》2009,25(1):57-64
A mutant designated as UV-3 was obtained from wild-type Enterobacter aerogenes 10293 through u.v. radiation. The activities of α-acetolactate decarboxylase (Ald), lactate dehydrogenase (Ldh) and diacetyl
reductase (Dr) in UV-3 were strongly attenuated, with the lowest activities at pH 7.0–7.5, and temperature between 36 and
39°C. Compared to the wild-type, the yield of diacetyl by UV-3 was increased 18.7-fold, up to 1.05 ± 0.01 g l−1. Acetoin and ethanol productions were decreased by 48.4 and 71.4%, respectively, but acetate yield was increased by 34.6%.
Optimum medium for diacetyl production by UV-3 contained 10% glucose, 0.5% peptone, 0.5% yeast extract powder, 0.01% (NH4)2SO4, 0.1% citric acid, 0.2% MnSO4 and 0.2% MgSO4, and this was determined by one-factor-at-a-time approach. Data from the five level central composite designs demonstrated
that initial pH of 7.0, temperature of 37°C and rotational speed of 180 rev/min were optimum processing parameters for diacetyl
production. The maximum yield of diacetyl could reach 1.35 g l−1 in a 5-l bioreactor. These results showed an enhancement of the non-enzymatic oxidative decarboxylation of α-acetolactate
and a decrease in the activities of Ald, Ldh and Dr as a consequence of diacetyl accumulation in UV-3. 相似文献
13.
Xuesong Zhao Juan Wang Jie Li Ling Fu Juan Gao Xiuli Du Hongtao Bi Yifa Zhou Guihua Tai 《Journal of industrial microbiology & biotechnology》2009,36(5):721-726
Fourteen phytopathogenic fungi were tested for their ability to transform the major ginsenosides to the active minor ginsenoside
Rd. The transformation products were identified by TLC and HPLC, and their structures were assigned by NMR analysis. Cladosporium fulvum, a tomato pathogen, was found to transform major ginsenoside Rb1 to Rd as the sole product. The following optimum conditions for transforming Rd by C. fulvum were determined: the time of substrate addition, 24 h; substrate concentration, 0.25 mg ml−1; temperature, 37°C; pH 5.0; and biotransformation period, 8 days. At these optimum conditions, the maximum yield was 86%
(molar ratio). Further, a preparative scale transformation with C. fulvum was performed at a dose of 100 mg of Rb1 by a yield of 80%. This fungus has potential to be applied on the preparation for Rd in pharmaceutical industry. 相似文献
14.
Zahir Ahmad Zahir Usman Ghani Muhammad Naveed Sajid Mahmood Nadeem Hafiz Naeem Asghar 《Archives of microbiology》2009,191(5):415-424
Ethylene synthesis is accelerated in response to various environmental stresses like salinity. Ten rhizobacterial strains
isolated from wheat rhizosphere taken from different salt affected areas were screened for growth promotion of wheat under
axenic conditions at 1, 5, 10 and 15 dS m−1. Three strains, i.e., Pseudomonas putida (N21), Pseudomonas aeruginosa (N39) and Serratia proteamaculans (M35) showing promising performance under axenic conditions were selected for a pot trial at 1.63 (original), 5, 10 and 15 dS m−1. Results showed that inoculation was effective even in the presence of higher salinity levels. P. putida was the most efficient strain compared to the other strains and significantly increased the plant height, root length, grain
yield, 100-grain weight and straw yield up to 52, 60, 76, 19 and 67%, respectively, over uninoculated control at 15 dS m−1. Similarly, chlorophyll content and K+/Na+ of leaves also increased by P. putida over control. It is highly likely that under salinity stress, 1-aminocyclopropane-1-carboxylic acid-deaminase activity of
these microbial strains might have caused reduction in the synthesis of stress (salt)-induced inhibitory levels of ethylene.
The results suggested that these strains could be employed for salinity tolerance in wheat; however, P. putida may have better prospects in stress alleviation/reduction. 相似文献
15.
16.
17.
Neetu Singh Piyush Pandey R. C. Dubey D. K. Maheshwari 《World journal of microbiology & biotechnology》2008,24(9):1669-1679
Bacterial isolates having antifungal and good plant growth-promoting attributes were isolated from chir-pine (Pinus roxburghii) rhizosphere. An isolate, Bacillus subtilis BN1 exhibited strong antagonistic activity against Macrophomina phaseolina, and other phytopathogens including Fusarium oxysporum and Rhizoctonia solani. It was characterized and selected for the present studies. BN1 resulted in vacuolation, hyphal squeezing, swelling, abnormal
branching and lysis of mycelia. The cell-free culture filtrate of BN1 inhibited the growth of M. phaseolina. Pot trial study resulted in statistically significant increase in seedling biomass besides reduction in root rot symptoms
in chir-pine seedlings. BN1 treatment resulted in 43.6% and 93.54% increases in root and shoot dry weights respectively, as
compared to control. Also, 80–85% seed viability was recorded in treatments receiving BN1 either alone or in the presence
of M. phaseolina, compared to 54.5% with M. phaseolina. Bioinoculant formulation study suggested that maximum viability of bacteria was in a sawdust-based carrier. B. subtilis BN1 produced lytic enzymes, chitinase and β-1,3-glucanase, which are known to cause hyphal degradation and digestion of the
cell wall component of M. phaseolina. In the presence of M. phaseolina, population of B1 was 1.5 × 104 c.f.u. g−1 root after one month, which increased to 4.5 × 104 c.f.u. g−1 root in three months. Positive root colonization capability of B. subtilis BN1 proved it as a potent biocontrol agent. 相似文献
18.
Hai-Nan Su Bin-Bin Xie Xiu-Lan Chen Jin-Xia Wang Xi-Ying Zhang Bai-Cheng Zhou Yu-Zhong Zhang 《Journal of applied phycology》2010,22(1):65-70
Allophycocyanin (APC) is a minor component of phycobiliproteins in cyanobacteria and red algae. This paper describes a simple
and inexpensive extracting method for isolating APC from Spirulina (Arthrospira) platensis with high efficiency. The crude phycobiliprotein extract was pretreated by ammonium sulfate fractionation. Then, by adding
hydroxylapatite into crude phycobiliprotein extract dissolved in 20 mM phosphate buffer (pH 7.0), APC was selectively adsorbed
by hydroxylapatite but C-phycocyanin (C-PC) was not. The hydroxylapatite was collected and APC was extracted from the crude
phycobiliprotein extract. Then, the enriched APC was washed off from the hydroxylapatite using 100 mM phosphate buffer (pH 7.0).
In this simple extracting method it was easy to remove C-PC and isolate APC in large amounts. The absorbance ratio A
650/A
280 of extracted APC reached 2.0. The recovery yield was 70%, representing 4.61 mg · g−1 wet weight. The extracted APC could be further purified by a simple anion-exchange chromatography with a pH gradient from
5.6 to 4.0. The absorbance ratio A
650/A
280 of the purified APC reached 5.0, and the overall recovery yield was 43%, representing 2.83 mg · g−1 wet weight. Its purity was confirmed by native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE. 相似文献
19.
Jin Zhou Ju Chu Yong-Hong Wang Si-Liang Zhang Ying-Ping Zhuang Zhong-Yi Yuan 《World journal of microbiology & biotechnology》2008,24(6):789-796
An intracellular S-adenosylmethionine synthetase (SAM-s) was purified from the fermentation broth of Pichia pastoris GS115 by a sequence chromatography column. It was purified to apparent homogeneity by (NH4)2SO4 fractionation (30–60%), anion exchange, hydrophobic interaction, anion exchange and gel filtration chromatography. HPLC showed
the purity of purified SAM-s was 91.2%. The enzyme was purified up to 49.5-fold with a final yield of 20.3%. The molecular
weight of the homogeneous enzyme was 43.6 KDa, as determined by electro-spray ionization mass spectrometry (ESI-MS). Its isoelectric
point was approximately 4.7, indicating an acidic character. The optimum pH and temperature for the enzyme reaction were 8.5
and 35 °C, respectively. The enzyme was stable at pH 7.0–9.0 and was easy to inactivate in acid solution (pH ≤ 5.0). The temperature
stability was up to 45 °C. Metal ions, such as, Mn2+ and K+ at the concentration of 5 mM had a slight activation effect on the enzyme activity and the Mg2+ activated the enzyme significantly. The enzyme activity was strongly inhibited by heavy metal ions (Cu2+ and Ag2+) and EDTA. The purified enzyme from the transformed Pichia pastoris synthesized S-adenosylmethionine (SAM) from ATP and l-methionine in vitro with a K
m of 120 and 330 μM and V
max of 8.1 and 23.2 μmol/mg/min for l-methionine and ATP, respectively. 相似文献
20.
Filipendula ulmaria (L.) Maxim (meadowsweet) is a medicinal plant that is claimed to have several biological activities, including anti-tumor,
anti-carcinogenic, anti-oxidant, anti-coagulant, anti-ulcerogenic, anti-microbial, anti-arthritic, and immunomodulatory properties.
This report describes, for the first time, an efficient plant regeneration system for F. ulmaria via adventitious shoot development from leaf, petiole, and root explants cultured on Murashige and Skoog’s minimal organics
medium containing different concentrations of thidiazuron (TDZ), benzyladenine, and kinetin either alone or in combination
with different auxins. Relatively extensive/prolific shoot regeneration was observed in all three explant types with TDZ in
combination with indole-3-acetic acid (IAA). Gibberellic acid (GA3), TDZ, and IAA combinations were also tested. The best shoot proliferation was observed among root explants cultured on media
supplemented with 0.45 μM TDZ + 2.85 μM IAA + 1.44 μM GA3. Regenerated shoots were transferred to rooting media containing different concentrations of either IAA, indole-3-butyric
acid (IBA), naphthalene acetic acid, or 2,4-dichlorophenoxyacetic acid. Most shoots developed roots on medium with 2.46 μM
IBA. Rooted explants were transferred to vermiculite in Magenta containers for a 2-wk acclimatization period and then finally
to plastic pots containing potting soil. The plantlets in soil were kept in growth chambers for 2 wk before transferring to
greenhouse conditions. 相似文献