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1.
Guang-Da Feng Song-Zhen Yang Yong-Hong Wang Guo-Zhen Zhao Ming-Rong Deng Hong-Hui Zhu 《Antonie van Leeuwenhoek》2014,105(6):1091-1097
A novel bacterial strain designated 9PNM-6T was isolated from an abandoned lead–zinc ore mine site in Meizhou, Guangdong Province, China. The isolate was found to be Gram-negative, rod-shaped, orange-pigmented, strictly aerobic, oxidase- and catalase-positive. Growth occurred at 0–4 % NaCl (w/v, optimum, 0 %), at pH 6.0–8.0 (optimum, pH 7.0) and at 15–32 °C (optimum, 28–30 °C). Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain 9PNM-6T belongs to the genus Sphingomonas, with the highest sequence similarities with Sphingomonas jejuensis NBRC 107775T (99.7 %), Sphingomonas koreensis KCTC 2882T (95.1 %) and Sphingomonas dokdonesis KCTC 12541T (95.1 %). The chemotaxonomic characteristics of strain 9PNM-6T were consistent with those of the genus Sphingomonas. The predominant respiratory quinone was identified as ubiquinone Q-10, the major polyamine as sym-homospermidine, and the major cellular fatty acids as C18:1 ω7c, C16:0, C16:1 ω7c and/or C16:1 ω6c and C14:0 2-OH. The major polar lipids are sphingoglycolipid, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatideylcholine, an unidentified phospholipid and four unidentified aminolipids. The genomic DNA G+C content of strain 9PNM-6T was determined to be 69.2 ± 0.6 mol%. Based on comparative analyses of morphological, physiological and chemotaxonomic data, and levels of DNA–DNA relatedness values, strain 9PNM-6T is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas gimensis sp. nov. (Type strain 9PNM-6T = GIMCC 1.655T = CGMCC 1.12671T = DSM 27569T) is proposed. 相似文献
2.
The effect of five constant temperatures of 21, 24, 27, 30 and 33 °C on adult life span, reproduction, oviposition behavior and larval developmental time of a bitter gourd inhabited coleopteran insect Epilachna dodecastigma (Wied.) (Coccinellidae) was determined in laboratory conditions under 70 ± 5 % relative humidity and a photoperiod of 12 L : 12 D. Larval developmental time of E. dodecastigma decreased as temperature increased from 21 to 33 °C. Life table data revealed that overall mortality was lowest at 27 °C and highest at 21 °C. Females lived longer than males at all temperatures; but longevity decreased with increase in temperature. Pre-oviposition period decreased significantly with increase in temperature up to 27 °C and thereafter increased at a slower rate; whereas oviposition period decreased significantly with increase in temperature. Fecundity and egg viability increased significantly with an increase in temperature up to 27 °C and thereafter decreased at a slower rate. The intrinsic rate of increase (r m ) was 0.1703, 0.1984, 0.2235, 0.2227 and 0.2181 day?1 at 21, 24, 27, 30 and 33 °C, respectively. The net reproductive rate and finite rate of increase was highest at 27 °C (R o = 112.05; λ = 1.4233) and lowest at 21 °C (R o = 51.23; λ = 1.2581). 相似文献
3.
Juying Huang Huagang Yan Fengzeng Jian Xingwen Wang 《Computer methods in biomechanics and biomedical engineering》2013,16(14):1516-1524
Nucleus replacement was deemed to have therapeutic potential for patients with intervertebral disc herniation. However, whether a patient would benefit from nucleus replacement is technically unclear. This study aimed to investigate the influence of nucleus pulposus (NP) removal on the biomechanical behavior of a lumbar motion segment and to further explore a computational method of biomechanical characteristics of NP removal, which can evaluate the mechanical stability of pulposus replacement. We, respectively, reconstructed three types of models for a mildly herniated disc and three types of models for a severely herniated disc based on a L4–L5 segment finite element model with computed tomography image data from a healthy adult. First, the NP was removed from the herniated disc models, and the biomechanical behavior of NP removal was simulated. Second, the NP cavities were filled with an experimental material (Poisson's ratio = 0.3; elastic modulus = 3 MPa), and the biomechanical behavior of pulposus replacement was simulated. The simulations were carried out under the five loadings of axial compression, flexion, lateral bending, extension, and axial rotation. The changes of the four biomechanical characteristics, i.e. the rotation degree, the maximum stress in the annulus fibrosus (AF), joint facet contact forces, and the maximum disc deformation, were computed for all models. Experimental results showed that the rotation range, the maximum AF stress, and joint facet contact forces increased, and the maximum disc deformation decreased after NP removal, while they changed in the opposite way after the nucleus cavities were filled with the experimental material. 相似文献
4.
5.
Juquan Jiang Yuanyuan Pan Lin Meng Shaoxin Hu Xiaoxia Zhang Baozhong Hu Jing Meng Cheng Li Haipeng Huang Kaibiao Wang Tingting Su 《Antonie van Leeuwenhoek》2013,104(5):685-694
A slightly halophilic bacterium (strain NEAU-ST10-25T) was isolated from saline–alkaline soils in Zhaodong City, Heilongjiang Province, China. The strain is a Gram-negative, aerobic motile rod. It accumulates poly-β-hydroxyalkanoate and produces exopolysaccharide. It produces beige-yellow colonies. Growth occurs at NaCl concentrations (w/v) of 0–15 % (optimum 3 %), at temperatures of 4–60 °C (optimum 35 °C) and at pH 6–12 (optimum pH 9). Its G+C content is 53.8 mol%. Phylogenetic analyses based on the separate 16S rRNA gene and concatenation of the 16S rRNA, gyrB and rpoD genes indicate that it belongs to the genus Halomonas in the class Gammaproteobacteria. The most phylogenetically related species is Halomonas alkaliphila DSM 16354T, with which strain NEAU-ST10-25T showed 16S rRNA, gyrB and rpoD gene sequence similarities of 99.2, 82.3 and 88.2 %, respectively. The results of DNA–DNA hybridization assays showed 60.47 ± 0.69 % DNA relatedness between strain NEAU-ST10-25T and H. alkaliphila DSM 16354T, 42.43 ± 0.37 % between strain NEAU-ST10-25T and Halomonas venusta DSM 4743T and 30.62 ± 0.43 % between strain NEAU-ST10-25T and Halomonas hydrothermalis DSM 15725T. The major fatty acids are C18:1 ω7c (62.3 %), C16:0 (17.6 %), C16:1 ω7c/C16:1 ω6c (7.7 %), C14:0 (2.9 %), C12:0 3-OH (2.8 %), C10:0 (2.1 %) and C18:1 ω9c (1.6 %) and the predominant respiratory quinone is ubiquinone 9 (Q-9). The proposed name is Halomonas zhaodongensis, NEAU-ST10-25T (=CGMCC 1.12286T = DSM 25869T) being the type strain. 相似文献
6.
Phytoplankton as a monitoring tool in a tropical urban shallow reservoir (Garças Pond): the assemblage index application 总被引:3,自引:3,他引:0
This study aimed at evaluating phytoplankton as a monitoring tool for water quality assessment in an urban shallow eutrophic reservoir considering temporal and vertical scales. Garças Reservoir is located in the Parque Estadual das Fontes do Ipiranga Biological Reserve (23°38′08″S and 23°40′18″S; 46°36′48″W and 46°38′00″W) that lies in the southeastern part of the Municipality of São Paulo, southeast Brazil. Samplings were carried out monthly during 8 consecutive years (1997–2004) following the water column vertical profile (5 depths: subsurface, 1, 2, 3 m and ~20 cm from the bottom). Abiotic variables analyzed were: water temperature, electric conductivity, DO, pH, total alkalinity, free CO2, dissolved inorganic carbon, N series, P series and SiO4H4. Biological variables studied were: total density, total biomass and chlorophyll a, which were integrated arithmetically. At the beginning of the 8 year series, Garças Reservoir was an eutrophic ecosystem with 20% of its surface covered by Eichhornia crassipes (phase I: January 1997–March 1998). Water hyacinth reached 70% of pond surface coverage (phase II: April 1998–August 1999), and then it was mechanically removed (phase III: September 1999–December 2004). After this intervention, drastic alteration in the limnological features was detected, leading to the conclusion that removal of the aquatic macrophyte modified nutrient dynamics drastically reduced water transparency and led to photosynthetic productivity and phytoplankton biomass increase, the latter becoming a physical barrier to light penetration. Twenty one functional groups ‘sensu’ Reynolds were identified. Cyanobacteria contribution played the main role during the drastic alterations that occurred after water hyacinth removal. Results of ecological status of reservoir using Q index showed statistical difference among the 3 limnological phases (one way ANOVA; F = 119.4; P = 0.000). Regarding Q index classification, Garças Reservoir limnological phases were characterized as follows: (1) phase I: 0 ≥ Q ≤ 2.9, medium to bad; (2) phase II: 1.4 ≥ Q ≤ 3, tolerable to medium; and (3) phase III: 0 ≥ Q ≤ 1.5, bad to tolerable ecological states. 相似文献
7.
Guangda Feng Songzhen Yang Yonghong Wang Qing Yao Honghui Zhu 《Current microbiology》2014,69(6):888-893
A Gram-negative bacterial strain, designated WB1T, was isolated from a domestic refrigerator in Guangzhou, PR China. Cells of strain WB1T were oxidase-negative, catalase-positive, strictly aerobic, non-spore-forming and non-motile coccobacilli with peritrichous fimbriae-like structures. The strain was able to grow at 10–40 °C with optimum growth at 28–30 °C, pH 6.0–8.0 (optimum, pH 7.0) and 0–6 % NaCl (w/v, optimum, 0.5 %). Phylogenetic analyses based on 16S rRNA gene and rpoB gene sequences revealed that strain WB1T belonged to the genus Acinetobacter and was most closely related to A. indicus DSM 25388T (97.2 % 16S rRNA gene sequence similarity) and A. radioresistens NBRC 102413T (96.8 %). The DNA G + C content of strain WB1T was 46.74 ± 0.04 mol % and the major fatty acids comprised summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C18:1 ω9c, C16:0 and C12:0. The predominant respiratory quinone was identified as Q-9 and the polar lipids as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and an unidentified phospholipid. Phenotypic, phylogenetic and chemotaxonomic data, including low DNA–DNA relatedness with closely related type strains, supported that strain WB1T represents a distinct novel species in the genus Acinetobacter, for which the name Acinetobacter refrigeratorensis sp. nov. was proposed. The type strain is WB1T (=GIMCC 1.663T = CCTCC AB 2014197T = KCTC 42011T). 相似文献
8.
Arshia Amin Nauman Khalid Ghenijan Osman Inam Ullah Khan Min Xiao Wen-Jun Li 《Antonie van Leeuwenhoek》2017,110(1):77-86
A Gram-staining positive, non-motile, rod-shaped, catalase positive and oxidase negative bacterium, designated NCCP-1331T, was isolated from a hot water spring soil collected from Tatta Pani, Kotli, Azad Jammu and Kashmir, Pakistan. The isolate grew at a temperature range of 18-40 °C (optimum 30 °C), pH 6.0–9.0 (optimum 7.0) and with 0–6 % NaCl (optimum 2 % NaCl (w/v)). The phylogenetic analysis based on 16S rRNA gene sequence revealed that strain NCCP-1331T belonged to the genus Streptomyces and is closely related to Streptomyces brevispora BK160T with 97.9 % nucleotide similarity, followed by Streptomyces drosdowiczii NRRL B-24297T with 97.8 % nucleotide similarity. The DNA–DNA relatedness values of strain NCCP-1331T with S. brevispora KACC 21093T and S. drosdowiczii CBMAI 0498T were 42.7 and 34.7 %, respectively. LL-DAP was detected as diagnostic amino acid along with alanine, glycine, leucine and glutamic acid. The isolate contained MK-9(H8) as the predominant menaquinone. Major polar lipids detected in NCCP-1331T were phosphatidylethanolamine, phosphatidylinositol and unidentified phospholipids. Major fatty acids were iso-C16: 0, summed feature 8 (18:1 ω7c/18:1 ω6c), anteiso-C15:0 and C16:0. The genomic DNA G + C content was 69.8 mol %. On the basis of phylogenetic, phenotypic and chemotaxonomic analysis, it is concluded that strain NCCP-1331T represents a novel species of the genus Streptomyces, for which the name Streptomyces caldifontis sp. nov. is proposed. The type strain is NCCP-1331T (=KCTC 39537T = CPCC 204147T). 相似文献
9.
Vahideh Tarhriz Vera Thiel Ghorbanali Nematzadeh Mohammad Amin Hejazi Johannes F. Imhoff Mohammad Saeid Hejazi 《Antonie van Leeuwenhoek》2013,104(6):1205-1215
A novel Gram-negative, aerobic, non-motile and rod-shaped bacterium was isolated from Qurugöl Lake near Tabriz city. The bacterium grew chemoorganolheterotrophically and chemolithoautotrophically. However, photo-organoheterotrophic, photo-lithoautotrophic and fermentative growth could not be demonstrated. The presence of photosynthesis genes pufL and pufM was not shown and photosynthesis pigments were not formed. Strain RCRI19T grew without NaCl and tolerated up to 3 % NaCl. Growth occurred at pH 6–9 (optimum, pH 7) and 15–55 °C (optimum 40–45 °C). Vitamins were not required for growth. The major fatty acids are C18:1 ω7C, 11-methyl C18:1 ω7C, C18:0 3-OH. The predominant respiratory quinone is ubiquinone Q-10. The G+C content of genomic DNA is 65.9 mol%. Analysis of 16S rRNA sequences showed that strain RCRI19T has the highest similarities with uncultured environmental sequences followed by members of the genera Rhodobacter (≤95.75 %), Haematobacter (≤95.53 %), Gemmobacter (≤95.17 %) and Falsirhodobacter (94.60 %) in the family Rhodobacteraceae. DNA–DNA relatedness between strain RCRI19T and the closest phylogenetically related strain, Rhodobacter blasticus LMG 4305T, was 20 %. Based on its phenotypic and chemotaxonomic characteristics and considering that it does not form photosynthetic pigments and is unable to grow phototrophically, it is concluded that strain RCRI19T cannot be included into the genus Rhodobacter and any of the other related genera. Therefore, we propose to place the new bacterium into a new genus and species for which the name Tabrizicola aquatica gen. nov. and sp. nov. is proposed. The type strain is RCRI19T (=BCCM/LMG 25773T = JCM 17277T = KCTC 23724T). 相似文献
10.
Michael A. Cotta Terence R. Whitehead Enevold Falsen Edward Moore Paul A. Lawson 《Antonie van Leeuwenhoek》2013,103(1):89-98
A polyphasic taxonomic study using morphological, biochemical, chemotaxonomic and molecular genetic methods was performed on six strains of unknown Gram-positive, nonspore-forming, facultative anaerobic coccus-shaped bacteria isolated from a swine-manure storage pit. On the basis of the 16S rRNA, RNA polymerase α-subunit (rpoA) and 60 kDa chaperonin (cpn60) gene sequence analyses, it was shown that all the isolates were enterococci but formed two separate lines of descent. Pairwise 16S rRNA gene sequence comparisons demonstrated that the two novel organisms were most closely related to each other (97.9 %) and to Enterococcus aquimarinus (97.8 %). Both organisms contained major amounts of C16:0, C16:1 ω7c, C16:1 ω7c, and C18:1 ω7c/12t/9t as the major cellular fatty acids. Based on biochemical, chemotaxonomic and phylogenetic evidence, the names Enterococcus lemanii sp. nov. (type strain PC32T = CCUG 61260T = NRRL B-59661T) and Enterococcus eurekensis sp. nov. (type strain PC4BT = CCUG 61259T = NRRL B-59662T) are proposed for these hitherto undescribed species. 相似文献
11.
Hong Kyo Park Ji-Hye Han Tae-Su Kim Yochan Joung Sung-Heun Cho Soon-Wo Kwon Seung Bum Kim 《Antonie van Leeuwenhoek》2015,107(1):47-53
A proteobacterial strain designated R1-3T was isolated from indoor air of a pharmaceutical environment. Cells were Gram-stain-negative, oxidase- and catalase-positive, aerobic, motile and rod-shaped. Strain R1-3T grew optimally at pH 7, 30 °C and in 0–2 % NaCl on R2A agar. The 16S rRNA gene sequence analysis indicated that strain R1-3T belongs to the genus Sphingomonas, and is closely related to Sphingomonas paucimobilis ATCC 29837T (98.4 % sequence similarity). However, the DNA–DNA relatedness between the two strains was 43 ± 5 % (reciprocal = 37 ± 3 %), which was well below the suggested level for species distinction. Sphingomonas yabuuchiae GTC868T (97.7 % 16S rRNA gene sequence similarity) and Sphingomonas pseudosanguinis G1-2T (97.6 %) were also found as distantly related taxa. Strain R1-3T was sensitive to most of the tested antibiotics except for erythromycin and streptomycin. The major fatty acid was a summed feature consisting of C18:1 ω7c and/or C18:1 ω6c, and minor proportions of C14:0 2-OH, C16:0 and a summed feature consisting of C16:1 ω7c and/or C16:1 ω6c were also present. The DNA G + C content was 67.2 ± 1.0 mol%. The major polyamines were sym-homospermidine and spermidine. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, and minor amounts of a sphingoglycolipid, a phospholipid, an aminoglycolipid and an unidentified lipid were also present. The phenotypic, phylogenetic and chemotaxonomic data not only supported the affiliation of strain R1-3T to the genus Sphingomonas, but also distinguished R1-3T from related species. On the basis of physiological, chemotaxonomic and phylogenetic evidences, strain R1-3T clearly merits recognition as a novel species of Sphingomonas, for which the name Sphingomonas aeria sp. nov. is proposed. The type strain is R1-3T (= KCTC 42061T = JCM 19859T). 相似文献
12.
Pernille Anastasia Skovgaard Børge Holm Christensen Claus Felby Henning Jørgensen 《Journal of industrial microbiology & biotechnology》2014,41(4):637-646
Recycling of enzymes has a potential interest during cellulosic bioethanol production as purchasing enzymes is one of the largest expenses in the process. By recycling enzymes after distillation, loss of sugars and ethanol are avoided, but depending on the distillation temperature, there is a potential risk of enzyme degradation. Studies of the rate of enzyme denaturation based on estimation of the denaturation constant K D was performed using a novel distillation setup allowing stripping of ethanol at 50–65 °C. Experiments were performed in a pilot-scale stripper, where the effect of temperature (55–65 °C) and exposure to gas–liquid and liquid–heat transmission interfaces were tested on a mesophilic and thermostable enzyme mixture in fiber beer and buffer. Lab-scale tests were included in addition to the pilot-scale experiments to study the effect of shear, ethanol concentration, and PEG on enzyme stability. When increasing the temperature (up to 65 °C) or ethanol content (up to 7.5 % w/v), the denaturation rate of the enzymes increased. Enzyme denaturation occurred slower when the experiments were performed in fiber beer compared to buffer only, which could be due to PEG or other stabilizing substances in fiber beer. However, at extreme conditions with high temperature (65 °C) and ethanol content (7.5 % w/v), PEG had no enzyme stabilizing effect. The novel distillation setup proved to be useful for maintaining enzyme activity during ethanol extraction. 相似文献
13.
Miwa Yamada Mitsuaki Ooe Tomoko Sasaki Masao Miyazaki 《Bioscience, biotechnology, and biochemistry》2017,81(12):2407-2410
An enzymatic method for 6-oxohexanoic acid production was developed using 6-aminohexanoic acid and an ω-amino group-oxidizing enzyme (ω-AOX) from Phialemonium sp. AIU 274. 6-Oxohexanoic acid was produced from 6-aminohexanoic acid with 100% yield by incubation with 0.3 U of the ω-AOX and 20 U of catalase at 30 °C for 30 h in 0.1 M potassium phosphate buffer (pH 7.0). 相似文献
14.
Abstract The total potential energy including nonbondedJuntorsional and hydrogen bond contributions has been computed for pustulan, a (1?6) linked β-D-glucan polysaccharide, as a function of rotational angles φ, ψ, and ω The (φ, ψ, ω)-space contains many local minima and at least three distinct deep minima. Two minima at (φ, ψ, ω)=(25°,190°,gg) and (φ, ψ, ω)=(65°,150°,gg) of almost equal energies have helical parameters (n=5.2, A=1.0Å) and (n=3.2, h= 1.5Å), respectively. A third minimum at (φ, ψ, ω)=(40°,70°gt) leads to an extended zig-zag structure (n=2.2, h=2.2Å). Energy maps obtained for gentiobiose, the disaccharide of pustulan, also reveal many local minima and the small energy differences among them indicate that gentiobiose is extremely flexible. Gentiodextrins, a family of cyclic molecules of (l?6)-β-D- glucose residues, were also studied. Conformations free from steric hindrance were found for cyclic molecules with three to six glucose residues. 相似文献
15.
Michael A. Cotta Terence R. Whitehead Enevold Falsen Edward Moore Paul A. Lawson 《Antonie van Leeuwenhoek》2013,103(6):1409-1418
A polyphasic taxonomic study using morphological, biochemical, chemotaxonomic and molecular genetic methods was performed on six strains of an unknown Gram-positive, nonspore-forming, facultative anaerobic coccus-shaped bacterium isolated from a swine-manure storage pit. On the basis of 16S rRNA, RNA polymerase-subunit (rpoA), and the 60-kilodalton chaperonin (cpn60) gene sequence analyses, it was shown that all the isolates were enterococci but formed two separate lines of descent. Pairwise 16S rRNA sequence comparisons demonstrated that the two novel organisms were most closely related to each other (97.9 %) and to Enterococcus aquimarinus (97.8 %). Both organisms contained major amounts of C16:0, C16:1 ω7c, and C18:1 ω7c/12t/9t as the major cellular fatty acids. Based on biochemical, chemotaxonomic, and phylogenetic evidence, the names Enterococcus lemanii sp. nov. (type strain PC32T = CCUG 61260T = NRRL B-59661T) and Enterococcus eurekensis sp. nov. (type strain PC4BT = CCUG 61259T = NRRL B-59662T) are proposed for the hitherto undescribed species. 相似文献
16.
Molecular dynamics (MD) computer simulations are utilized to better understand the dynamics of small (N = 5) endohedral Ne@C60 aggregates. Multiple runs at various temperatures are used to increase the reliability of our statistics. The aggregate holds together until somewhere between T = 1150 and 1200 K, where it dissociates, showing no intermediate sign of melting or fullerene disintegration. When the temperature is increased to around T = 4000 K, the encapsulated neon atoms begin to leave the aggregate, with the fullerene molecules still remaining intact. At temperatures near T = 4400 K, thermal disintegration of the fullerenes preempts the aggregate dissociation. Above this temperature neon atoms are more quickly released and the fullerenes form a larger connected structure, with bonding taking place in atom pairs from different original fullerene molecules. Escape constants and half lives are calculated for the temperature range 4000 K ≤ T ≤ 5000 K. The agreements and disagreements of results of this work with experiments suggest that classical MD simulations are useful in describing fullerene systems at low temperatures and near disintegration, but require development of new techniques before it is possible to accurately model windowing at temperatures below T = 3000 K. 相似文献
17.
Hossein Tavakol 《Molecular simulation》2013,39(13):1113-1121
Potential energy surfaces (PESs) for tautomerism and two dynamic motions of 3-hydroxy-5-(1H-pyrrol-2-yl)-2H-pyrrol-2-one and its tautomer were calculated using density functional theory. Calculated energies confirm that T1 is 10.95 kJ mol? 1 more stable than T2. Dynamic study of possible motions shows the high energy-level transition state at D8 = 90° for ring rotation and at D15 = 80° and 90° for rotation of OH bond, respectively, in T1 and T2. In addition, calculated rate constant for conversion of T1 to T2 (tautomerism) is 116 M? 1 s? 1, for relative rotations of rings in T1 and T2 are, respectively, 5.62 × 10? 2 and 1.53 M? 1 s? 1 and for rotations of OH bond in T1 and T2 are, respectively, 3.56 × 105 and 6.15 × 104 M? 1 s? 1. In the next part of the study, orbital occupancies, natural bond orbitals (NBO) charges and hybridisation in relative rotation of rings and internal reaction coordinate (IRC) steps have been extracted to study the possibility of level crossing. These data show that PESs for IRC and ring rotation have different symmetries. So that these two potential curves cannot have effective non-adiabatic level crossing. However, the levels are weakly avoided or the possibility of level crossing is higher than related system because the energy difference between their barrier energies is not very high. 相似文献
18.
1. Poikilothermic animals incorporate more polyunsaturated fatty acids (PUFAs) into their cellular membranes as temperature declines, suggesting an increased sensitivity to PUFA limitation in cool conditions. To test this we raised Daphnia magna at different temperatures and investigated the effect of varying dietary PUFA on life history parameters (i.e. growth, reproduction) and the PUFA composition of body tissue and eggs. 2. Upon a PUFA‐rich diet (Cryptomonas sp.) females showed higher concentrations of several ω3 PUFAs in their body tissue at 15 °C than at 20 °C and 25 °C, indicating a greater structural requirement for ω3 PUFAs at low temperature. Their eggs had an equal but higher concentration of ω3 PUFAs than their body tissue. 3. In a life history experiment at 15 and 20 °C we supplemented a diet of a PUFA‐free cyanobacterium with the ω3 PUFA eicosapentaenoic acid (EPA). The growth of D. magna was more strongly EPA limited at low temperature. A greater requirement for structural EPA at 15 °C was indicated by a steeper increase in somatic EPA content with dietary EPA compared to 20 °C. 4. At 20 °C the development of eggs to successful hatching was high when EPA was supplied to the mothers. At 15 °C the hatching success was generally poor, despite of a higher maternal provision of EPA to eggs, compared to that at 20 °C, suggesting that EPA alone was insufficient for proper neonatal development at the low temperature. The growth of offspring from mothers raised at 20 °C without EPA supplementation was very low, indicating that the negative effects of EPA deficiency can be carried on to the next generation. 5. The fatty acid composition of Daphnia sp. in published field studies shows increasing proportions of saturated fatty acids with increasing environmental temperature, whereas ω3 PUFAs and EPA show no clear pattern, suggesting that variations in dietary PUFA may mask temperature‐dependent adjustments in ω3 PUFA concentrations of cladocerans in nature. 相似文献
19.
Harald Galatis Karin Martin Peter Kämpfer Stefanie P. Glaeser 《Antonie van Leeuwenhoek》2013,103(5):1165-1171
A Gram-negative, rod-shaped organism, isolated from the surface of the medical leech Hirudo verbana was characterized phenotypically and genotypically. The calculated 16S rRNA gene sequence similarities to those of the most closely related species grouped strain E84T into the genus Devosia showing the highest similarities to Devosia limi (98.1 %), followed by Devosia psychrophila (97.9 %), Devosia neptuniae (97.3 %), and Devosia glacialis (97.5 %). Chemotaxonomic analyses showed that the major quinone was ubiquinone Q-10. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol and three glycolipids. The major fatty acid profile consisted of C18:1 ω7c 11-methyl, C19:0 cyclo ω8c, and C16:0, C18:0 and C18:1 ω7c with C18:0 3OH as hydroxylated fatty acid. This profile is very similar to those of the patterns reported for the already described Devosia species. The results of DNA–DNA hybridization, physiological and biochemical tests allowed both genotypic and phenotypic differentiation of strain E84T from all other Devosia species suggesting a novel species for which the name Devosia epidermidihirudinis sp. nov. is proposed, with the type strain E84T (=CIP 110375T = LMG 26909T = CCM 8398T). 相似文献
20.
Iftikhar Ahmed Muhammad Ehsan Yeseul Sin Jayoung Paek Nauman Khalid Rifat Hayat Young H. Chang 《Antonie van Leeuwenhoek》2014,105(2):325-333
The taxonomic status of a bacterium, strain NCCP-246T, isolated from rhizosphere of Vigna mungo, was determined using a polyphasic taxonomic approach. The strain NCCP-246T can grow at 16–37 °C (optimum 32 °C), at pH ranges of 6–8 (optimum growth occurs at pH 7) and in 0–4 % (w/v) NaCl. Phylogenetic analysis based upon on 16S rRNA gene sequence comparison revealed that strain NCCP-246T belonged to genus Sphingobacterium. Strain NCCP-246T showed highest similarity to the type strain of Sphingobacterium canadense CR11T (97.67 %) and less than 97 % with other species of the genus. The DNA–DNA relatedness value of strain NCCP-246T with S. canadense CR11T and Sphingobacterium thalpophilum JCM 21153T was 55 and 44.4 %, respectively. The chemotaxonomic data revealed the major menaquinone as MK-7 and dominant cellular fatty acids were summed feature 3 [C16:1 ω7c/C16:1 ω6c] (37.07 %), iso-C15:0 (28.03 %), C16:0 (11.85 %), C17:0 cyclo (8.84 %) and C14:0 (2.42 %). The G+C content of the strain was 39.2 mol%. On the basis of DNA–DNA hybridization, phylogenetic analyses, physiological and, biochemical data, strain NCCP-246T can be differentiated from the validly named members of genus Sphingobacterium and thus represents as a new species, for which the name, Sphingobacterium pakistanensis sp. nov. is proposed with the type strain NCCP-246T (= JCM18974 T = KCTC 23914T). 相似文献