It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can norma...It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can normally be significantly accelerated by bacterial activity. However,this paper reports on the corrosion of highly active Mg interestingly inhibited by an algal-symbiotic bacterium Bacillus altitudinis. The corrosion of Mg in the presence of the bacterium drastically reduced by one order of magnitude after 14 days of immersion. This means that the algal-symbiotic bacterium widely available in natural ocean environments may be employed as a green and sustainable inhibitor in the marine industry. Based on electrochemical measurements, surface analyses and microbe experiments, a combined inhibition mechanism is proposed in the paper to interpret the interesting corrosion behavior of Mg.展开更多
One in 58 strains of bacteria isolated from the compost showed clear colonies after a few days of growth on the plates containing medium made of only agar and water.Water suspension contained only agar (2 and 8g·...One in 58 strains of bacteria isolated from the compost showed clear colonies after a few days of growth on the plates containing medium made of only agar and water.Water suspension contained only agar (2 and 8g·L -1 ) with two controls (normal saline,LB medium) was inoculated with the bacterium BR5-1 to see whether there was an increasement of the alive bacteria concentration after 48 h of the growth.The results showed that there was a significant rising of the alive bacteria concentration in the agar suspension (6.5×10 3 and 6.0×10 3 cfu·mL -1 ) compared to that in the normal saline control (6.1×10 2 cfu·mL -1 ),and it was far lower than that in LB (Luria-Bertani) control (1.1×10 8 cfu·mL -1 ).In conclusion,the bacterium strain BR5-1 could degrade agar.展开更多
-- A red pigment that has better biological properties is produced by marine bacterium strain S- 9801. The extraction methods, physicochemical and toxicity of the pigment have been studied.Dissolubility of pigment in ...-- A red pigment that has better biological properties is produced by marine bacterium strain S- 9801. The extraction methods, physicochemical and toxicity of the pigment have been studied.Dissolubility of pigment in the five organic solvent has been tested, and ethanol is optimally chosen for extraction. Physicochemical characteristics of this pigment was stable. The absorbance of the pigment solution was no losing when put under natural light for 10 days or treated by UV for 30 minutes, color of the pigment unchanged after 100 ℃ hythere for 1 h or 80 ℃ xerother for 2 h. The median lethal dose (LD50) of the rat by celiac injection was 670.04 mg/kg and minimum lethal dose of oral was greater than 2 000 mg/kg.展开更多
2-haloacid dehalogenases constitute a group of dehalogenases which are capable of dehalogenating the halogenated organic compounds. So far, the 2-haloacid dehalogenases have been found in many bacteria, but not in Par...2-haloacid dehalogenases constitute a group of dehalogenases which are capable of dehalogenating the halogenated organic compounds. So far, the 2-haloacid dehalogenases have been found in many bacteria, but not in Paracoccus genus. In the present study, one enzyme 2-haloacid dehalogenase(designated as Deh99), induced by DL-2-chloropropionate(DL-2-CPA), was purified from the marine bacterium Paracoccus sp. DEH99, isolated from marine sponge Hymeniacidon perlevis. The enzyme of Deh99 was purified to homogeneity by ammonium sulfate precipitation, ion exchange chromatography(Q-Sepharose HP), and Superdex 200 gel filtration chromatography. The molecular weight of Deh99 was estimated to be 25.0 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE), and 50.0 kDa natively by gel filtration chromatography. The enzyme of Deh99 stereospecifically dehalogenated L-2-CPA to produce D-lactate, with an apparent Michaelis-Menten constant(Km) value of 0.21 mmol L-1 for L-2-CPA. The optimal pH and temperature for Deh99 activity were 10.0 and 40℃, respectively. The enzyme of Deh99 acted on short-carbon-chain 2-haloacids, with the highest activity towards monochloroacetate. The activity of Deh99 was slightly affected by DTT and EDTA, but strongly inhibited by Cu2+ and Zn2+. The enzyme of Deh99 shows unique substrate specificity and inhibitor sensitivities compared to previously characterized 2-haloacid dehalogenases and is the reported one about purified 2-haloacid dehalogenase isolated from the bacteria of Paracoccus genus.展开更多
Microorganisms living in polar zones play an important part as the potential source of organic activity materials with low temperature characteristics in the biotechnological applications. A psychrotrophic bacterium (...Microorganisms living in polar zones play an important part as the potential source of organic activity materials with low temperature characteristics in the biotechnological applications. A psychrotrophic bacterium (strain Ar/w/b/75°/10/5), producing cellulase at low temperatures during late-exponential and early-stationary phases of cell growth, was isolated from sea ice-covered surface water in Chuckchi Sea, Arctic. This bacterium, with rod cells, was Gram-negative, slightly halophilic. Colony growing on agar plate was in black. Optimum growth temperature was 15℃. No cell growth was observed at 35℃ or above. Optimum salt concentration for cell growth was between 2 and 3 % of sodium chloride in media. Maximal cellulase activity was detected at a temperature of 35℃ and pH8. Cellulase was irreversibly inactivated when incubated at 55℃ within 30 min. Enzyme can be kept stable at the temperature no higher than 25℃. Of special interest was that this bacterium produced various extracellular enzymes including cellulase, amylase, agar hydrolase and protease, at low or moderate temperature conditions, which is certainly of it potential value for applications.展开更多
A Gram negative bacterium Ar/W/b/75°25′N/1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25′N, and longitude 162°25′W in Chukchi sea, Arctic. The strain can...A Gram negative bacterium Ar/W/b/75°25′N/1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25′N, and longitude 162°25′W in Chukchi sea, Arctic. The strain can grow at the temperature range from 7℃ to 30℃, and grow better at 30℃. It can not grow at 40℃. Keeping certain salinity concentration in medium is necessary for cell growth. It grows well in medium containing salinity concentration from 0.5% to 10% sodium chloride. Glucose, sucrose and soluble starch can be utilized by the strain, among which glucose is the optimal carbon source. Peptone is the optimal organic nitrogen source for cell growth and protease producing, and ammonium nitrate is the optimal inorganic nitrogen source. About 75 7% of total protease of the strain are extracellular enzyme. Optimal temperature for proteolytic activity is at 40℃. Protease of the strain keeps stable below 40℃, and shows high proteolytic activity within the pH range from 7 to 11.展开更多
Halomonas sp.YSR-3 was isolated from the Yellow Sea and identified as a polyphosphate-accumulating bacterium and the characteristics of its intracellular polyphosphate(polyP)granules and phosphorus absorption were stu...Halomonas sp.YSR-3 was isolated from the Yellow Sea and identified as a polyphosphate-accumulating bacterium and the characteristics of its intracellular polyphosphate(polyP)granules and phosphorus absorption were studied.Most YSR-3 cells stored one or two polyP granules in regular appearance and high-density.The diameter of the granules was about 400 nm measuring by a transmission electron microscope(TEM).After stained with 4,6-diamidino-2-phenylindole(DAPI)and visualized by a fluorescence microscope,the cells turned blue and the granules were bright yellow.The composition of granules includes P(major ingredient),Mg,S,K,and Ca as detected by an energy dispersive X-ray spectrometer(EDS).When inorganic phosphorus(po34-)and ferric ion(Fe3+)were added into media,the biomass increased and the cells formed intracellular polyP granules owing to the phosphorus assimilation from media.The YSR-3 obtained higher biomass by adding 0.02 g/L FePO4 than 0.005 g/L and 0.01 g/L FePO4;however,the phosphorus absorption was higher with 0.01 g/L FePO4 than 0.005 g/L and 0.02 g/L FePO4.The optical density at wavelength 480 nm(OD480nm)was 0.79 and 100%cells could form intracellular polyP granules.These results show that strain YSR-3 is able to acquire higher biomass and absorb more inorganic phosphorus when 0.01 g/L FePO4 is added.The characteristics of absorbing and storing phosphorus as intracellular inorganic polyP granules have a potential for application in high-efficiency phosphorus removal in wastewater treatment.展开更多
Vibrio harveyi, known as a pathogenic bacterium caused severe secondary bacterial infections of the large yellow croaker Larimichthys crocea, was identified as an endosymbiont in the marine parasitic ciliate protozoan...Vibrio harveyi, known as a pathogenic bacterium caused severe secondary bacterial infections of the large yellow croaker Larimichthys crocea, was identified as an endosymbiont in the marine parasitic ciliate protozoan Cryptocaryon irritans. Meta 16 S sequencing method was used to identify the bacterial flora in C. irritans, and V.harveyi was isolated via culture-dependent method. Vibrio harveyi was observed in cytoplasm of C. irritans at the stage of tomont both by transmission electron microscopy and by Fluorescence in situ hybridization; no signal,however, was detected in nucleus area. The relationship between V. harveyi and C. irritans and the role of endosymbiotic V. harveyi in C. irritans merit further investigation.展开更多
Rotation is a method to effectively regulate the soil microbial community structure and alleviate the obstacles of continuous planting of eggplant in facilities.High-throughput sequencing technology was used to study ...Rotation is a method to effectively regulate the soil microbial community structure and alleviate the obstacles of continuous planting of eggplant in facilities.High-throughput sequencing technology was used to study the change of beneficial bacteria diversity and structure at the first fruit stage of continuous eggplant rhizosphere soil affected by rotation combined with Bacillus subtilis fertilizer.The result showed that beneficial bacteria in the rhizosphere soil samples of eggplant at the phylum classification level included Actinobacteria,Chloroflexi,Acidobacteria,Planctomycetes and Cyanobacteria.At the level of genus classification,the beneficial bacteria in the rhizosphere soil samples of eggplant were Bacillus,Arthrobacter,Sphingomonas and Streptomyces.The significantly differences were observed in the abundance of soil dominant bacteria and beneficial bacteria at phylum level and genus classification among different treatments.At the phylum level,compared with CK treatment,the relative abundances of Acidobacteria and Proteobacteria in BB treatment were increased by 34.4%and 20.2%,respectively.At the level of genus classification,the beneficial bacterial Arthrobacter abundance in BB treatment was 1.44 times than that of CK treatment and was significantly higher than that in CF treatment.Moreover,the total uptake of N,P and K by eggplants in BB treatment and BFN treatment were 1.68 and 1.35 times than those of CK treatment,respectively.The above results showed that the combined treatment of microbial fertilizer and rotation could increased the soil bacterial community diversity and the abundance of beneficial bacteria in the first fruit stage of eggplant,which indeed enhanced the absorption of N,P and K by continuous eggplant plants,thereby alleviating the obstacles of continuous cropping of eggplant.展开更多
Leather industries that uses the conventional chrome tanning process are subjected to high risk of contamination due to the emission of toxic Cr(VI)that poses a serious threat to the environment and human’s wellbeing...Leather industries that uses the conventional chrome tanning process are subjected to high risk of contamination due to the emission of toxic Cr(VI)that poses a serious threat to the environment and human’s wellbeing.The present study were made to isolate and characterize chromium tolerant bacteria in the samples collected from four different plots of Bantala Tannery,Kolkata,West Bengal,India.Pure chromium tolerant bacterial strains were isolated from the tannery sludge samples and their relative MIC(Minimum Inhibitory Concentration)were recorded at different concentrations of Cr(VI)salts to select the highest chromium tolerant bacterium.The selected bacterium was further taken for their growth studies followed by different cultural,morphological and molecular analysis(16S rDNA).The bacterial strain was further studied through SEM(Scanning Electron microscopy)and EDX(Energy Dispersive X-ray)spectroscopy which revealed that TW4 was a gram positive,rod shaped,endospore forming,pleomorphic bacterium with phylogenetic similarities with Isoptericola sp.and genebank accession number SUB1732465 TW4 KX640927.展开更多
An agar-degrading bacterium,designated as Pseudoalteromonas sp. NJ21,was isolated from an Antarctic sediment sample. The agarase gene a ga1161 from Pseudoalteromonas sp. NJ21 consisting of a 2 382-bp coding region was...An agar-degrading bacterium,designated as Pseudoalteromonas sp. NJ21,was isolated from an Antarctic sediment sample. The agarase gene a ga1161 from Pseudoalteromonas sp. NJ21 consisting of a 2 382-bp coding region was cloned. The gene encodes a 793-amino acids protein and was found to possess characteristic features of the Glyco_hydro_42 family. The recombinant agarase(r Aga1161) was overexpressed in Escherichia coli and purified as a fusion protein. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were 30–40°C and 8.0,respectively. rAga1161 was found to maintain as much as 80% of its maximum activity at 10°C,which is typical of a coldadapted enzyme. The pattern of agar hydrolysis demonstrated that the enzyme is an β-agarase,producing neoagarobiose(NA2) as the final main product. Furthermore,this work is the first proof of an agarolytic activity in Antarctic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine,food and cosmetic industries.展开更多
Eight known compounds were isolated from a marine-derived bacterium Streptoverticillium luteoverticillatum 11014 using bioassay-guided fractionations. Their structures were identified by spectral analysis as bis (4-hy...Eight known compounds were isolated from a marine-derived bacterium Streptoverticillium luteoverticillatum 11014 using bioassay-guided fractionations. Their structures were identified by spectral analysis as bis (4-hydroxybenzyl) ether (1), p-hydroxyphenylethyl alcohol (2), N-(4-hydroxyphenethyl) acetamide (3), indole-3 carboxylic acid methyl ester (4), dibenzo[b,e] [1,4]dioxine (5), thymine (6), cytosine deoxyribonucleoside (7) and 2, 3-butanediol (8). These compounds were evaluated for their cytotoxic activities against K562 cell line with the SRB method for the first time. Compounds 2 and 4 showed cytotoxcities with IC50 values of 101.1 and 165.3 μmol L-1, respectively. All compounds were isolated from S. luteoverticillatum 11014 for the first time.展开更多
The effects of sulfate reduced bacterium (SRB) on the corrosion behavior of 10CrMoAl steel in seawater were studied by chemical immersion, potentiodynamic polarization, electrochemical impedance spectroscopy measureme...The effects of sulfate reduced bacterium (SRB) on the corrosion behavior of 10CrMoAl steel in seawater were studied by chemical immersion, potentiodynamic polarization, electrochemical impedance spectroscopy measurement, and scanning electron microscope techniques. The results show that the content of element sulfur in the corrosion product of 10CrMoAl steel in seawater with SRB is up to 9.23%, which is higher than that of the same in sterile seawater. X-ray diffraction demonstrates that the main corrosion product is FeS. SRB increases the corrosion rate by anodic depolarization of the metabolized sulfide product. SEM observation indicates that the corrosion product is not distributed continuously; in addition, bacilliform sulfate-reduced bacterium accumulates on the local surface of 10CrMoAl steel. Hence, SRB enhances sensitivity to the localized corrosion of 10CrMoAl steel in seawater.展开更多
A moderately thermophilic acidophilic iron-oxidizing bacterium ZW-1 was isolated from Dexing mine, Jiangxi Province, China. The morphological, biochemical and physiological characteristics, 16S rRNA sequence and biole...A moderately thermophilic acidophilic iron-oxidizing bacterium ZW-1 was isolated from Dexing mine, Jiangxi Province, China. The morphological, biochemical and physiological characteristics, 16S rRNA sequence and bioleaching characterization of strain ZW-1 were studied. The optimum growth temperature is 48 ℃, and the optimum initial pH is 1.9. The strain can grow autotrophically by using ferrous iron or elemental sulfur as sole energy sources. The strain is also able to grow heterotrophically by using peptone and yeast extract powder, but not glucose. The cell density of strain ZW-1 can reach up to 1.02×108 /mL with addition of 0.4 g/L peptone. A phylogenetic tree was constructed by comparing with the published 16S rRNA sequences of the relative bacteria species. In the phylogenetic tree, strain ZW-1 is closely relative to Sulfobacilus acidophilus with more than 99% sequence similarity. The results of bioleaching experiments indicate that the strain could oxidize Fe2+ efficiently, and the maximum oxidizing rate is 0.295 g/(L·h). It could tolerate high concentration of Fe3+ and Cu2+ (35 g/L and 25 g/L, respectively). After 20 d, 44.6% of copper is extracted from chalcopyrite by using strain ZW-1 as inocula.展开更多
We present the logistic growth model to study the stochastic resonance(SR)in a bacterium growth systemunder the simultaneous action of two external multiplicative cross-correlation noises and periodic external forcing...We present the logistic growth model to study the stochastic resonance(SR)in a bacterium growth systemunder the simultaneous action of two external multiplicative cross-correlation noises and periodic external forcing.Theexpression of the signal-to-noise ratio(SNR)for a bacterium growth system is derived by using the theory of SNR inthe adiabatic limit.Based on SNR,we discuss the effects of self-correlation time τ_1 and τ_2,cross-correlation time τ_3and cross-correlation strength λ on the SNR.It is found that the self-correlation time τ_1 and τ_2,and cross-correlationstrength λ enhance the SR of the bacterium growth system,while cross-correlation time τ_3 weakens the SR of thebacterium growth system.展开更多
基金the National Natural Science Foundation of China (Nos.51731008,52250710159,51671163,51901198)the National Key Research and Development Program of China (No.2017YFB0702100)。
文摘It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can normally be significantly accelerated by bacterial activity. However,this paper reports on the corrosion of highly active Mg interestingly inhibited by an algal-symbiotic bacterium Bacillus altitudinis. The corrosion of Mg in the presence of the bacterium drastically reduced by one order of magnitude after 14 days of immersion. This means that the algal-symbiotic bacterium widely available in natural ocean environments may be employed as a green and sustainable inhibitor in the marine industry. Based on electrochemical measurements, surface analyses and microbe experiments, a combined inhibition mechanism is proposed in the paper to interpret the interesting corrosion behavior of Mg.
基金Supported by National High-tech Research and Development Program of China (863 Program) (20060110Z4023)
文摘One in 58 strains of bacteria isolated from the compost showed clear colonies after a few days of growth on the plates containing medium made of only agar and water.Water suspension contained only agar (2 and 8g·L -1 ) with two controls (normal saline,LB medium) was inoculated with the bacterium BR5-1 to see whether there was an increasement of the alive bacteria concentration after 48 h of the growth.The results showed that there was a significant rising of the alive bacteria concentration in the agar suspension (6.5×10 3 and 6.0×10 3 cfu·mL -1 ) compared to that in the normal saline control (6.1×10 2 cfu·mL -1 ),and it was far lower than that in LB (Luria-Bertani) control (1.1×10 8 cfu·mL -1 ).In conclusion,the bacterium strain BR5-1 could degrade agar.
文摘-- A red pigment that has better biological properties is produced by marine bacterium strain S- 9801. The extraction methods, physicochemical and toxicity of the pigment have been studied.Dissolubility of pigment in the five organic solvent has been tested, and ethanol is optimally chosen for extraction. Physicochemical characteristics of this pigment was stable. The absorbance of the pigment solution was no losing when put under natural light for 10 days or treated by UV for 30 minutes, color of the pigment unchanged after 100 ℃ hythere for 1 h or 80 ℃ xerother for 2 h. The median lethal dose (LD50) of the rat by celiac injection was 670.04 mg/kg and minimum lethal dose of oral was greater than 2 000 mg/kg.
基金supported by National Basic Research Program of China(973 program,Grant No.2009CB724700)the Hundred Talent Program of the Chinese Academy of Sciences(A1097)National Natural Science Foundation of China(No.31100092)
文摘2-haloacid dehalogenases constitute a group of dehalogenases which are capable of dehalogenating the halogenated organic compounds. So far, the 2-haloacid dehalogenases have been found in many bacteria, but not in Paracoccus genus. In the present study, one enzyme 2-haloacid dehalogenase(designated as Deh99), induced by DL-2-chloropropionate(DL-2-CPA), was purified from the marine bacterium Paracoccus sp. DEH99, isolated from marine sponge Hymeniacidon perlevis. The enzyme of Deh99 was purified to homogeneity by ammonium sulfate precipitation, ion exchange chromatography(Q-Sepharose HP), and Superdex 200 gel filtration chromatography. The molecular weight of Deh99 was estimated to be 25.0 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE), and 50.0 kDa natively by gel filtration chromatography. The enzyme of Deh99 stereospecifically dehalogenated L-2-CPA to produce D-lactate, with an apparent Michaelis-Menten constant(Km) value of 0.21 mmol L-1 for L-2-CPA. The optimal pH and temperature for Deh99 activity were 10.0 and 40℃, respectively. The enzyme of Deh99 acted on short-carbon-chain 2-haloacids, with the highest activity towards monochloroacetate. The activity of Deh99 was slightly affected by DTT and EDTA, but strongly inhibited by Cu2+ and Zn2+. The enzyme of Deh99 shows unique substrate specificity and inhibitor sensitivities compared to previously characterized 2-haloacid dehalogenases and is the reported one about purified 2-haloacid dehalogenase isolated from the bacteria of Paracoccus genus.
基金This work was supported in part by State Oceanic Administration(No.99614)the State Ministry of Science and Technology(No.2001 DIA50040 6)National Nature Science Foundation of China(No.40006010).
文摘Microorganisms living in polar zones play an important part as the potential source of organic activity materials with low temperature characteristics in the biotechnological applications. A psychrotrophic bacterium (strain Ar/w/b/75°/10/5), producing cellulase at low temperatures during late-exponential and early-stationary phases of cell growth, was isolated from sea ice-covered surface water in Chuckchi Sea, Arctic. This bacterium, with rod cells, was Gram-negative, slightly halophilic. Colony growing on agar plate was in black. Optimum growth temperature was 15℃. No cell growth was observed at 35℃ or above. Optimum salt concentration for cell growth was between 2 and 3 % of sodium chloride in media. Maximal cellulase activity was detected at a temperature of 35℃ and pH8. Cellulase was irreversibly inactivated when incubated at 55℃ within 30 min. Enzyme can be kept stable at the temperature no higher than 25℃. Of special interest was that this bacterium produced various extracellular enzymes including cellulase, amylase, agar hydrolase and protease, at low or moderate temperature conditions, which is certainly of it potential value for applications.
文摘A Gram negative bacterium Ar/W/b/75°25′N/1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25′N, and longitude 162°25′W in Chukchi sea, Arctic. The strain can grow at the temperature range from 7℃ to 30℃, and grow better at 30℃. It can not grow at 40℃. Keeping certain salinity concentration in medium is necessary for cell growth. It grows well in medium containing salinity concentration from 0.5% to 10% sodium chloride. Glucose, sucrose and soluble starch can be utilized by the strain, among which glucose is the optimal carbon source. Peptone is the optimal organic nitrogen source for cell growth and protease producing, and ammonium nitrate is the optimal inorganic nitrogen source. About 75 7% of total protease of the strain are extracellular enzyme. Optimal temperature for proteolytic activity is at 40℃. Protease of the strain keeps stable below 40℃, and shows high proteolytic activity within the pH range from 7 to 11.
基金Supported by the National Natural Science Foundation of China(Nos.51308245,31570061)the Open Project of Jiangsu Provincial Engineering Laboratory for Advanced Materials of Salt Chemical Industry(No.SF201408)the Open Project of Jiangsu Provincial Key Construction Laboratory of Probiotics Preparation(No.JSYSZJ2017006)
文摘Halomonas sp.YSR-3 was isolated from the Yellow Sea and identified as a polyphosphate-accumulating bacterium and the characteristics of its intracellular polyphosphate(polyP)granules and phosphorus absorption were studied.Most YSR-3 cells stored one or two polyP granules in regular appearance and high-density.The diameter of the granules was about 400 nm measuring by a transmission electron microscope(TEM).After stained with 4,6-diamidino-2-phenylindole(DAPI)and visualized by a fluorescence microscope,the cells turned blue and the granules were bright yellow.The composition of granules includes P(major ingredient),Mg,S,K,and Ca as detected by an energy dispersive X-ray spectrometer(EDS).When inorganic phosphorus(po34-)and ferric ion(Fe3+)were added into media,the biomass increased and the cells formed intracellular polyP granules owing to the phosphorus assimilation from media.The YSR-3 obtained higher biomass by adding 0.02 g/L FePO4 than 0.005 g/L and 0.01 g/L FePO4;however,the phosphorus absorption was higher with 0.01 g/L FePO4 than 0.005 g/L and 0.02 g/L FePO4.The optical density at wavelength 480 nm(OD480nm)was 0.79 and 100%cells could form intracellular polyP granules.These results show that strain YSR-3 is able to acquire higher biomass and absorb more inorganic phosphorus when 0.01 g/L FePO4 is added.The characteristics of absorbing and storing phosphorus as intracellular inorganic polyP granules have a potential for application in high-efficiency phosphorus removal in wastewater treatment.
基金The National Natural Science Foundation of China under contract Nos 31372504,41176115 and 41476118
文摘Vibrio harveyi, known as a pathogenic bacterium caused severe secondary bacterial infections of the large yellow croaker Larimichthys crocea, was identified as an endosymbiont in the marine parasitic ciliate protozoan Cryptocaryon irritans. Meta 16 S sequencing method was used to identify the bacterial flora in C. irritans, and V.harveyi was isolated via culture-dependent method. Vibrio harveyi was observed in cytoplasm of C. irritans at the stage of tomont both by transmission electron microscopy and by Fluorescence in situ hybridization; no signal,however, was detected in nucleus area. The relationship between V. harveyi and C. irritans and the role of endosymbiotic V. harveyi in C. irritans merit further investigation.
基金Supported by the Natural Science Joint Guidance Foundation of Heilongjiang Province,China(LH2019C041)Special Fund for Agro-scientific Research in Public Interest,China(201503109)Heilongjiang Natural Science Foundation,China(C2015016)。
文摘Rotation is a method to effectively regulate the soil microbial community structure and alleviate the obstacles of continuous planting of eggplant in facilities.High-throughput sequencing technology was used to study the change of beneficial bacteria diversity and structure at the first fruit stage of continuous eggplant rhizosphere soil affected by rotation combined with Bacillus subtilis fertilizer.The result showed that beneficial bacteria in the rhizosphere soil samples of eggplant at the phylum classification level included Actinobacteria,Chloroflexi,Acidobacteria,Planctomycetes and Cyanobacteria.At the level of genus classification,the beneficial bacteria in the rhizosphere soil samples of eggplant were Bacillus,Arthrobacter,Sphingomonas and Streptomyces.The significantly differences were observed in the abundance of soil dominant bacteria and beneficial bacteria at phylum level and genus classification among different treatments.At the phylum level,compared with CK treatment,the relative abundances of Acidobacteria and Proteobacteria in BB treatment were increased by 34.4%and 20.2%,respectively.At the level of genus classification,the beneficial bacterial Arthrobacter abundance in BB treatment was 1.44 times than that of CK treatment and was significantly higher than that in CF treatment.Moreover,the total uptake of N,P and K by eggplants in BB treatment and BFN treatment were 1.68 and 1.35 times than those of CK treatment,respectively.The above results showed that the combined treatment of microbial fertilizer and rotation could increased the soil bacterial community diversity and the abundance of beneficial bacteria in the first fruit stage of eggplant,which indeed enhanced the absorption of N,P and K by continuous eggplant plants,thereby alleviating the obstacles of continuous cropping of eggplant.
文摘Leather industries that uses the conventional chrome tanning process are subjected to high risk of contamination due to the emission of toxic Cr(VI)that poses a serious threat to the environment and human’s wellbeing.The present study were made to isolate and characterize chromium tolerant bacteria in the samples collected from four different plots of Bantala Tannery,Kolkata,West Bengal,India.Pure chromium tolerant bacterial strains were isolated from the tannery sludge samples and their relative MIC(Minimum Inhibitory Concentration)were recorded at different concentrations of Cr(VI)salts to select the highest chromium tolerant bacterium.The selected bacterium was further taken for their growth studies followed by different cultural,morphological and molecular analysis(16S rDNA).The bacterial strain was further studied through SEM(Scanning Electron microscopy)and EDX(Energy Dispersive X-ray)spectroscopy which revealed that TW4 was a gram positive,rod shaped,endospore forming,pleomorphic bacterium with phylogenetic similarities with Isoptericola sp.and genebank accession number SUB1732465 TW4 KX640927.
基金Supported by the Public Science and Technology Research Funds Project of Ocean(No.201105027)the Shandong Province Young and the Middle-Aged Scientists Research Awards Fund(No.DS2010HZ001)the Basic Scientific Research Funds of First Institute of Oceanography,State Oceanic Administration(No.GY02-2011G17)
文摘An agar-degrading bacterium,designated as Pseudoalteromonas sp. NJ21,was isolated from an Antarctic sediment sample. The agarase gene a ga1161 from Pseudoalteromonas sp. NJ21 consisting of a 2 382-bp coding region was cloned. The gene encodes a 793-amino acids protein and was found to possess characteristic features of the Glyco_hydro_42 family. The recombinant agarase(r Aga1161) was overexpressed in Escherichia coli and purified as a fusion protein. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were 30–40°C and 8.0,respectively. rAga1161 was found to maintain as much as 80% of its maximum activity at 10°C,which is typical of a coldadapted enzyme. The pattern of agar hydrolysis demonstrated that the enzyme is an β-agarase,producing neoagarobiose(NA2) as the final main product. Furthermore,this work is the first proof of an agarolytic activity in Antarctic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine,food and cosmetic industries.
基金The work was financially supported by the Project of Chinese National Programs for High Technology Research and Development(No.2003AA624020)the National Nattual Science Foundation of China(Nos.30472136 and 30470196).
文摘Eight known compounds were isolated from a marine-derived bacterium Streptoverticillium luteoverticillatum 11014 using bioassay-guided fractionations. Their structures were identified by spectral analysis as bis (4-hydroxybenzyl) ether (1), p-hydroxyphenylethyl alcohol (2), N-(4-hydroxyphenethyl) acetamide (3), indole-3 carboxylic acid methyl ester (4), dibenzo[b,e] [1,4]dioxine (5), thymine (6), cytosine deoxyribonucleoside (7) and 2, 3-butanediol (8). These compounds were evaluated for their cytotoxic activities against K562 cell line with the SRB method for the first time. Compounds 2 and 4 showed cytotoxcities with IC50 values of 101.1 and 165.3 μmol L-1, respectively. All compounds were isolated from S. luteoverticillatum 11014 for the first time.
文摘The effects of sulfate reduced bacterium (SRB) on the corrosion behavior of 10CrMoAl steel in seawater were studied by chemical immersion, potentiodynamic polarization, electrochemical impedance spectroscopy measurement, and scanning electron microscope techniques. The results show that the content of element sulfur in the corrosion product of 10CrMoAl steel in seawater with SRB is up to 9.23%, which is higher than that of the same in sterile seawater. X-ray diffraction demonstrates that the main corrosion product is FeS. SRB increases the corrosion rate by anodic depolarization of the metabolized sulfide product. SEM observation indicates that the corrosion product is not distributed continuously; in addition, bacilliform sulfate-reduced bacterium accumulates on the local surface of 10CrMoAl steel. Hence, SRB enhances sensitivity to the localized corrosion of 10CrMoAl steel in seawater.
基金Project(2004CB619204) supported by the National Basic Research Program of ChinaProject(50621063) supported by the National Natural Science Foundation of ChinaProject(DYXM-115-02-2-07) supported by China Ocean Mineral Resources Research and Development Association
文摘A moderately thermophilic acidophilic iron-oxidizing bacterium ZW-1 was isolated from Dexing mine, Jiangxi Province, China. The morphological, biochemical and physiological characteristics, 16S rRNA sequence and bioleaching characterization of strain ZW-1 were studied. The optimum growth temperature is 48 ℃, and the optimum initial pH is 1.9. The strain can grow autotrophically by using ferrous iron or elemental sulfur as sole energy sources. The strain is also able to grow heterotrophically by using peptone and yeast extract powder, but not glucose. The cell density of strain ZW-1 can reach up to 1.02×108 /mL with addition of 0.4 g/L peptone. A phylogenetic tree was constructed by comparing with the published 16S rRNA sequences of the relative bacteria species. In the phylogenetic tree, strain ZW-1 is closely relative to Sulfobacilus acidophilus with more than 99% sequence similarity. The results of bioleaching experiments indicate that the strain could oxidize Fe2+ efficiently, and the maximum oxidizing rate is 0.295 g/(L·h). It could tolerate high concentration of Fe3+ and Cu2+ (35 g/L and 25 g/L, respectively). After 20 d, 44.6% of copper is extracted from chalcopyrite by using strain ZW-1 as inocula.
基金Supported by the Natural Science Foundation of Yunnan Province under Grant Nos.2005A0080m-2 and 08C0235the Key Subjects Fund for Condensed Physics of Qujing Normal University
文摘We present the logistic growth model to study the stochastic resonance(SR)in a bacterium growth systemunder the simultaneous action of two external multiplicative cross-correlation noises and periodic external forcing.Theexpression of the signal-to-noise ratio(SNR)for a bacterium growth system is derived by using the theory of SNR inthe adiabatic limit.Based on SNR,we discuss the effects of self-correlation time τ_1 and τ_2,cross-correlation time τ_3and cross-correlation strength λ on the SNR.It is found that the self-correlation time τ_1 and τ_2,and cross-correlationstrength λ enhance the SR of the bacterium growth system,while cross-correlation time τ_3 weakens the SR of thebacterium growth system.
