共查询到20条相似文献,搜索用时 15 毫秒
1.
An improved technique for sampling lotic invertebrates 总被引:1,自引:1,他引:0
The electrophoretic characterization of an Artemia population from a saline lake of the Chilean Andes with unusual ecological features (Salar de Atacama, 23° 30′ S; 68° 10′
W) was carried out with the aim of comparing its genetic variation with, and genetic similarity to, representative populations
of A. persimilis (Buenos Aires, Argentina) and A. franciscana (San Francisco Bay, USA). Based on the analysis of 22 loci it is concluded that the Chilean population and that from San
Francisco are conspecific (D = 0.144), while the Chilean strain and A. persimilis are congeneric species (D = 1.171), differing in more than 40% of the loci. Parameters measuring genetic variation (e.g., percentage of loci polymorphic,
mean number of alleles per locus, mean heterozygosity per locus) demonstrate that values for the Chilean Artemia (50.0, 1.68, 0.126, respectively) are within the range for bisexual Artemia in general and A. franciscana in particular. 相似文献
2.
Mathurot Chaiharn Saisamorn Lumyong 《World journal of microbiology & biotechnology》2009,25(2):305-314
Plant growth-promoting rhizobacteria (PGPR) are known to influence plant growth by various direct or indirect mechanisms.
A total of 216 phosphate-solubilizing bacterial isolates were isolated from different rice rhizospheric soil in Northern Thailand.
These isolate were screened in vitro for their plant growth-promoting activities such as solubilization of inorganic phosphate,
ammonia (NH3), catalase and cell wall-degrading enzyme activity. It was found that 100% solubilized inorganic phosphate, 77.77% produced
NH3 and most of the isolates were positive for catalase. In addition, some strains also produced cell wall-degrading enzymes
such as protease (7%), chitinase (1%), cellulase (3%) and β-glucanase (3%), as evidenced by phenotypic biochemical test and quantitative assay using spectrophotometry. The isolates
could exhibit more than two or three plant growth-promoting (PGP) traits, which may promote plant growth directly or indirectly
or synergistically. Part of this study focused on the effect of NaCl, temperature, and pH on a specific the bacterial isolate
Acinetobacter CR 1.8. Strain CR 1.8 was able to grow on up to 25% NaCl, between 25 and 55°C, and at pH 5–9. Maximum solubilization of tricalcium
phosphate and aluminium phosphate was obtained at neutral pH, and 37°C. Strain CR 1.8 had protease activity but no cellulase,
β-glucanase and cellulase activities. 相似文献
3.
Yi-Guang Chen Shu-Kun Tang Yu-Qin Zhang Zhao-Yang Li Lang-Bo Yi Yong-Xia Wang Wen-Jun Li Xiao-Long Cui 《Antonie van Leeuwenhoek》2009,96(1):63-70
A novel Gram-positive, halotolerant, non-sporulating, non-motile, catalase-positive, oxidase-negative and aerobic bacterium,
designated strain JSM 078085T, was isolated from sea water collected from the South China Sea. Strain JSM 078085T exhibited a rod-coccus growth cycle and produced a yellow pigment. The strain was able to grow in the presence of 0–12% (w/v)
NaCl and at pH 6.0–9.5 and 4–35°C; optimum growth was observed at pH 7.0 and 25–30°C in the absence of NaCl. The peptidoglycan
type was A4α (l-Lys–l-Ala–l-Glu). Cell-wall sugars contained galactose and glucose. Strain JSM 078085T contained menaquinone MK-9(H2) as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major
polar lipids. The major cellular fatty acids were anteiso-C15:0, iso-C15:0 and anteiso-C17:0 and the DNA G + C content was 63.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that
strain JSM 078085T should be assigned to the genus Arthrobacter, being most closely related to the type strain of Arthrobacter rhombi (sequence similarity 97.1%), and the two strains formed a distinct lineage in the phylogenetic tree. The level of DNA–DNA
relatedness between strain JSM 078085T and the type strain of Arthrobacter rhombi was 10.6%. The combination of phylogenetic analysis, DNA–DNA relatedness, phenotypic characteristics and chemotaxonomic data
supported the view that strain JSM 078085T represents a novel species of the genus Arthrobacter, for which the name Arthrobacter halodurans sp. nov. is proposed. The type strain is JSM 078085T (=DSM 21081T=KCTC 19430T).
The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain JSM 078085T is EU583729. 相似文献
4.
Abdeljabbar Hedi Marie-Laure Fardeau Najla Sadfi Abdellatif Boudabous Bernard Ollivier Jean-Luc Cayol 《Extremophiles : life under extreme conditions》2009,13(2):313-319
A new halophilic anaerobe was isolated from the hypersaline surface sediments of El-Djerid Chott, Tunisia. The isolate, designated
as strain 6SANG, grew at NaCl concentrations ranging from 14 to 30%, with an optimum at 20–22%. Strain 6SANG was a non-spore-forming,
non-motile, rod-shaped bacterium, appearing singly, in pairs, or occasionally as long chains (0.7–1 × 4–13 μm) and showed
a Gram-negative-like cell wall pattern. It grew optimally at pH values between 7.2 and 7.4, but had a very broad pH range
for growth (5.9–8.4). Optimum temperature for growth was 42°C (range 30–50°C). Strain 6SANG required yeast extract for growth
on sugars. Glucose, sucrose, galactose, mannose, maltose, cellobiose, pyruvate, and starch were fermented. The end products
from glucose fermentation were acetate, butyrate, lactate, H2, and CO2. The G + C ratio of the DNA was 34.3 mol%. Strain 6SANG exhibited 16S rRNA gene sequence similarity values of 91–92% with
members of the genus Halobacteroides, H. halobius being its closest phylogenetic relative. Based on phenotypic and phylogenetic characteristics, we propose that this bacterium
be classified as a novel species of a novel genus, Halanaerobaculum tunisiense gen. nov., sp. nov. The type strain is 6SANGT (=DSM 19997T = JCM 15060T). 相似文献
5.
Adhyayan Sharan Shikha Nandan Singh Darmwal Rajeeva Gaur 《World journal of microbiology & biotechnology》2008,24(6):753-759
A total of 198 bacterial strains were isolated from various niches of saline–alkali soils, out of which 85 strains were able
to solubilize phosphate on plates at 30 °C. The strain RMLU-26, identified as Xanthomonas campestris, was the most efficient with its ability to solubilize P, subjected to N-methyl-N′-nitro-N-nitrosoguanidine (NTG) for development of mutants. The P solubilizing ability of X. campestris is reported for the first time. The wild type and mutant strains of X. campestris revealed a differential response to various stress factors (high pH, temperature, and salt concentration). The mutant strain
revealed maximum P solubilization (67.1%) at 30 °C and pH 8.0 while the wild type strain showed maximum solubilization (41.9%)
at 35 °C and pH 7.0. Percent P2O5 solubilization by both strains revealed a steep decline in tricalcium phosphate solubilization with an increase in NaCl concentration
from 0.5 to 10% along with a concomitant drop in pH of the medium from 8.0 to 4.5 in wild type and 4.0 in mutant strain. However,
a 1.5- to 2-fold increase in ‘P’ solubilization was observed in the mutant strain when compared to the wild type strain in
the presence of NaCl. The overall improved tolerance of the strains to alkalinity and salinity could be due to accumulation
and/or secretion of specific solute (xanthan). 相似文献
6.
Chen YG Cui XL Li WJ Xu LH Wen ML Peng Q Jiang CL 《Extremophiles : life under extreme conditions》2008,12(2):197-203
A novel pale-yellow-pigmented, moderately halophilic, facultatively alkaliphilic, non-motile, non-spore-forming, catalase-
and oxidase-positive, obligately aerobic Gram-positive coccus, strain YIM-C678T was isolated from a saline soil sample collected from a hypersaline habitat in the Qaidam basin, northwest China. The organism
grew at 4–37°C and pH 6.0–11.0, with optimum growth at 25°C and pH 8.0. Strain YIM-C678T grew optimally in the presence of 10–12% (w/v) NaCl and growth was observed in 1–25% (w/v) NaCl. The cell wall murein type
was l-Lys-Gly5. Major cellular fatty acids were anteiso-C15:0, iso-C15:0, iso-C16:0 and C16:0. Menaquinone 6 (MK-6) was the major respiratory quinone. The DNA G + C content was 46.5 mol%. Phylogenetic analysis based
on 16S rRNA gene sequences indicated that the strain YIM-C678T belonged to the family Staphylococcaceae and was most closely related to the eight described species of the genus Salinicoccus with sequence similarities from 92.2 (S. luteus YIM 70202T) to 97.5% (S. kunmingensis YIM Y15T). The DNA–DNA relatedness between strain YIM-C678T and S. kunmingensis YIM Y15T was 35.4%. Chemotaxonomic data and 16S rRNA gene sequence analysis supported the affiliation of strain YIM-C678T with the genus Salinicoccus. The combination of phylogenetic analysis, phenotypic characteristics, chemotaxonomic differences and DNA–DNA hybridization
data supported the view that the bacterium represents a novel species of the genus Salinicoccus, for which the name Salinicoccus salitudinis sp. nov. is proposed, with YIM-C678T (=DSM 17846 = CGMCC 1.6299) as the type strain. 相似文献
7.
Three strains of gram-positive, motile, rod-shaped and boron (B)-tolerant bacterium were isolated from naturally B containing
soil of Hisarcik area in the Kutahya Province, Turkey. The strains, designated as T-14A, T-15ZT and T-17s, produced spherical or ellipsoidal endospores in a terminal bulging sporangium. The strains required B for the
growth and can tolerate more than 450 mM B. These also tolerated up to 7.0% (w/v) NaCl in the presence of 50 mM B in agar
medium but grew optimally without NaCl. The temperature range for growth was 16–37°C (optimal of 30°C), whereas the pH range
was 6.5–9.0 (optimal of 7.5–8.5). The DNA G + C content was 41.1–42.2 mol% and the predominant cellular fatty acid was iso-C15:0. The major respiratory quinone system was detected as MK-7 and the diamino acid of the peptidoglycan was meso-diaminopimelic acid. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis of 16S rRNA gene sequences
data and DNA–DNA re-association values, we concluded that the three strains belong to a novel species of the genus Bacillus, the type strain of which is T-15ZT and for which we proposed the name, B. boroniphilus sp. nov. (DSM 17376T = IAM 15287T = ATCC BAA-1204T). 相似文献
8.
Leila Hayashi Alex A. Santos Gabriel S. M. Faria Beatriz G. Nunes Marina S. Souza Alessandra L. D. Fonseca Pedro L. M. Barreto Eurico C. Oliveira Zenilda L. Bouzon 《Journal of applied phycology》2011,23(3):337-343
Four strains of Kappaphycus alvarezii were cultivated in the subtropical waters of Florianópolis, Santa Catarina State, Brazil (27°29′19′′ S/48°32′28′′ W), from
February 2009 to February 2010. Seaweeds were cultivated on floating raft near of mussel farms. Salinity ranged from 29 to
36 psu and temperature from 17.1 to 28.5°C. Higher growth rates (5.12–4.29% day−1) were measured in summer and autumn, showing a positive correlation between growth rate and water temperature. Lower growth
rates (0.54–0.32% day−1) occurred in winter, resulted mainly by biomass loss. Significant differences were observed among the strains in spring and
the brown tetrasporophytic strain was the only one which failed to recover, being excluded of the experiments. The effect
of cultivation periods (36, 42, and 97 days) on carrageenan yield, gel strength, and viscosity were analyzed. Carrageenan
yields were higher for plants kept 42 days in the sea (28%), against 25% for 36 and 97 days. There were no significant differences
in carrageenan yield among the strains analyzed. Viscosity increased with the increase of cultivation period, while gel strength
seemed to vary at random. Tetrasporangia and cystocarps were not observed, and lost fragments did not attach outside the raft.
In general, dissolved inorganic nitrogen concentration decreased around the cultivation area as compared to the mussel farm.
Results show that cultivation of K. alvarezii is technically feasible in subtropical waters and can be associated with local mussel farms, mitigating the eutrophication
and, eventually, increasing the economic return of the farmers. 相似文献
9.
The leaves of the common box,Buxus sempervirens (Buxaceae), become red as the level of a red carotenoid,anhydroeschscholtzxanthin, increases 总被引:1,自引:0,他引:1
Kazuko Ida Kazumori Masamoto Takashi Maoka Yasuhiro Fujiwara Satomi Takeda Emiko Hasegawa 《Journal of plant research》1995,108(3):369-376
Carotenoids from the leaves of the common box,Buxus sempervirens (Buxaceae), which turn red in late autumn to winter, were analyzed by reversed-phase HPLC. A novel carotenoid, monoanhydroeschscholtzxanthin
(3), was isolated from the red-colored leaves. UV-VIS, MS,1H-NMR and CD spectral data showed that the structure of 3 was (3S)-2′, 3′, 4′, 5′-tetradehydro-4, 5′-retro-β, β-caroten-3-ol.
As well as anhydroeschscholtzxanthin (2), the major red carotenoid in the leaves, eschscholtzxanthin (4) was identified. Very
small amounts of yellow carotenoids (neoxanthin, violaxanthin, lutein and β-carotene), which are major components of green
leaves, were present in the red-colored leaves. The amounts of chlorophylla andb in the leaves decreased markedly during coloration, even at the early stages, whereas those of the yellow carotenoids decreased
gradually. In contrast, the content of 2, a red carotenoid, increased steadily during coloration. The biosynthetic pathway
of 2 inB. sempervirens was deduced tentatively on the basis of the individual carotenoid contents during autumnal coloration. 相似文献
10.
Rosa María Camacho Juan Carlos Mateos Orfil González-Reynoso Lilia Arely Prado Jesús Córdova 《Journal of industrial microbiology & biotechnology》2009,36(7):901-909
The present study was conducted to investigate the capability of Haloarcula marismortui to synthesize esterases and lipases, and the effect of physicochemical conditions on the growth and the production of esterases
and lipases. Finally, the effect of NaCl concentration and temperature on esterase and lipase activities was studied using
intracellular crude extracts. In order to confirm the genomic prediction about the esterase and lipase synthesis, H. marismortui was cultured on a rich medium and the crude extracts (intra- or extracellular) obtained were assayed for both activities
using p-nitrophenyl esters and triacylglycerides as substrates. Studies on the kinetics of growth and production of esterase and
lipase of H. marismortui were performed, reaching a maximum growth rate of 0.053 h−1 and maximal productions of intracellular esterase and lipase of 2.094 and 0.722 U l−1 using p-nitrophenyl valerate and p-nitrophenyl laurate, respectively. Both enzymes were produced as growth-associated metabolites. The effects of temperature,
pH, and NaCl concentration on the growth rate and production of enzymes were studied by using a Box–Behnken response surface
design. The three response variables were significantly influenced by the physicochemical factors and an interaction effect
between temperature and NaCl concentration was also evidenced. The surface response method estimated the following maximal
values for growth rate and productions of esterase and lipase: 0.086 h−1 (at 42.5°C, pH 7.4, and 3.6 mol l−1 NaCl), 2.3 U l−1 (at 50°C, pH 7.5, and 4.3 mol l−1 NaCl), and 0.58 U l−1 (at 50°C, pH 7.6, and 4.5 mol l−1 NaCl), respectively. Esterases were active at different salt concentrations, showing two optimal activities (at 0.5 and 5 mol l−1 NaCl), which suggested the presence of two different esterases. Interestingly, in the absence of salt, esterase retained
50% residual activity. Esterases and lipase activities were maximal at 45°C and inactive at 75°C. This study represents the
first report evidencing the synthesis of esterase and lipase by H. marismortui. 相似文献
11.
Z. B. Namsaraev O. B. Babasanova Y. E. Dunaevsky V. N. Akimov D. D. Barkhutova V. M. Gorlenko B. B. Namsaraev 《Microbiology》2010,79(4):491-499
A Gram reaction positive, spore-forming, facultative anaerobic bacterium belonging to the Phylum Firmicutes, was isolated from alkaline hot (80°C, pH 9.8) spring Tsenher, Central Mongolia. The cells were rod shaped, feebly motile,
peritrichously flagellated. Strain T4T was moderately thermophilic with optimum growth at 60°C. Maximum temperature for growth
was between 70 and 75°C; minimum temperature for growth was between 35 and 30°C. Alkalitolerant, optimum pH for growth was
8.0; minimum pH for growth was between 5.0 and 5.5 and maximum was between 10.5 and 10.8. The growth was observed at NaCl
concentrations of 0–5% (w/v) with the optimum at 0.2–0.5%. No growth was observed at 6% NaCl (w/v). Aerobically, the strain
utilized proteinaceous substrates, organic acids and a range of carbohydrates including glucose, ribose, sucrose and xylose
as well. Anaerobically, only glucose and sucrose were utilized. Strain T4T produced thermostable alkaline subtilisin-like serine proteinase. The G + C content was 44.2 mol % (td). On the basis of
16S rRNA gene sequence similarity strain T4T was shown to be closely related to the members of the genus Anoxybacillus (family Bacillaceae, class “Bacilli”). DNA-DNA hybridization data revealed that strain T4T had only 38% relatedness to A. flavithermus and 28% relatedness to A. pushchinoensis. Based on its morphology, physiology, phylogenetic relationship and its low DNA-DNA relatedness values with validly published
species of Anoxybacillus, it is proposed that strain T4T represents a novel species Anoxybacillus mongoliensis sp. nov., with the type strain T4T (=DSM 19169 =VKM 2407). 相似文献
12.
Enrichment, isolation, and characterization of 4-chlorophenol-degrading bacterium Rhizobium sp. 4-CP-20 总被引:2,自引:0,他引:2
The objectives of this research were to monitor the variations of species in mixed cultures during the enrichment period,
isolate species and identify and characterize the pure 4-chlorophenol (4-CP) degrading strains from enriched mixed cultures.
Strain Rhizobium sp. 4-CP-20 was isolated from the acclimated mixed culture. The DGGE result indicated that strain Rhizobium sp. 4-CP-20 was undetectable at the beginning but detectable after 2 weeks of enrichment. The optimum growth temperatures
for Rhizobium sp. 4-CP-20 were both 36°C using 350 mg l−1 glucose or sodium acetate as the substrate. The optimum pH range for degrading 100 mg l−1 4-CP was between 6.89 and 8.20. Strain Rhizobium sp. 4-CP-20 could degrade 4-CP completely within 3.95 days, as the initial 4-CP concentration was 100 mg l−1. If the initial 4-CP concentration was higher than 240 mg l−1, the growth of bacterial cells and the activity of degrading 4-CP were both inhibited. 相似文献
13.
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
14.
Mao-hong Zhou Jian-she Ma Jun Li Hai-ren Ye Ke-xin Huang Xiao-wei Zhao 《Biotechnology and Bioprocess Engineering》2008,13(5):545-551
A bacterial strain able to produce κ-carrageenase, designated WZUC10, was isolated from a live specimen of the red alga Plocamium telfainae collected in the East China Sea. The phylogenetic evidence and phenotypic features indicate that this strain belongs to the
genus Pseudoalteromonas. WZUC10 requires NaCl for growth and κ-carrageenan to induce κ-carrageenase synthesis; galactose and lactose do not induce
it. The optimal growth temperature is 23∼27°C. The secreted enzyme, which has a molecular mass of 45 kDa, breaks down κ-carrageenan
into κ-neocarratetraose sulfate and larger oligosaccharides with a repeating β-D-Galp4S-(1→4)-α-D-AnGalp structure, but cannot degrade κ-neocarratetraose sulfate or κ-neocarrahexaose sulfate into κ-neocarrabiose sulfate. The enzyme
retains 90% of its activity after 2 h at 40°C and is completely inactivated after 7.5 min at 70°C. The enzyme’s optimal temperature
is 30°C and its optimal pH is 7.5. The enzyme-catalyzed reaction follows Michaelis-Menten kinetics, with the Michaelis constant
(K
m) and the turnover number (k) being 0.015 mM and 125 s−1, respectively. WZUC10 produces 50 U/mL κ-carrageenase after cultivation at 25°C for 35 h on a medium containing 80 g/L glucose,
5 g/L corn steep liquor, 3 g/L κ-carrageenan, and 15 g/L NaCl. κ-Neocarratetraose sulfate was prepared simply with precipitation
by ethanol:water (5:1, v/v). 相似文献
15.
I.-Hsien Tsu C.-Y. Huang J.-L. Garcia Bharat K. C. Patel Jean-Luc Cayol Larry Baresi Robert A. Mah 《Archives of microbiology》1998,170(4):313-317
A new halotolerant Desulfovibrio, strain CVLT (T = type strain), was isolated from a solar saltern in California. The curved, gram-negative, nonsporeforming cells (0.3
× 1.0–1.3 μm) occurred singly, in pairs, or in chains, were motile by a single polar flagellum and tolerated up to 12.5% NaCl.
Strain CVLT had a generation time of 60 min when grown in lactate-yeast extract medium under optimal conditions (37°C, pH 7.6, 2.5% NaCl).
It used lactate, pyruvate, cysteine, or H2/CO2 + acetate as electron donors, and sulfate, sulfite, thiosulfate, or fumarate as electron acceptors. Elemental sulfur, nitrate,
or oxygen were not used. Sulfite and thiosulfate were disproportionated to sulfate and sulfide. The G+C content of the DNA
was 62 mol%. Phylogenetic analysis revealed that Desulfovibrio fructosovorans was the nearest relative. Strain CVLT is clearly different from other Desulfovibrio species, and is designated Desulfovibrio senezii sp. nov. (DSM 8436).
Received: 27 February 1998 / Accepted: 15 June 1998 相似文献
16.
D'Souza David R. Morgan Richard D. Parashar Vijay Capalash Neena Sharma Prince 《World journal of microbiology & biotechnology》2004,20(6):593-598
A thermophile, isolated from geothermal areas in the northern Himalayan region of India, was identified by partial 16S rDNA
sequence (GenBank accession # AF482430) analysis as Anoxybacillus flavithermus. The isolate produced BflI (REBASE # 4910), a Type II restriction endonuclease, which recognized the sequence 5′-CCNNNNN/NNGG-3′ and was the isoschizomer
of BsiYI. The enzyme was purified to homogeneity by passing through Cibacron Blue F3GA agarose, DEAE-cellulose, heparin-agarose
and MonoQ FPLC. The purified enzyme (MW 36 kDa) worked best at 60 °C in Promega's buffer C and preferentially required Co++(0.4 mM) as cofactor followed by Mg++(10 mM) and Mn++(1 mM). The enzyme showed high specific activity and worked in the presence of high concentrations of β-mercaptoethanol (200
mM), Triton-X-100 (25%), urea (30%), formamide (6%) and guanidine (40 mM) and showed no star activity in the presence of 40%
glycerol. In the absence of any stabilizing agent, BflI retained t
1/2 for at least 96 h at 37 °C, 6 h at 60 °C and 6 months at 4 °C. N-terminal sequencing showed that its first 10 amino acid
residues were DFHEDKTIAR.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Genetic variability and interpopulational differentiation of Artemia strains from South America 总被引:2,自引:2,他引:0
Seven Artemia samples from three South American countries (Chile, Brazil, Peru) were studied by starch electrophoresis with the aim of comparing levels of genetic variation and genetic similarity to representative populations of A. franciscana (San Francisco Bay, California, USA) and A. persimilis (Buenos Aires, Argentina), which are species endemic to the New World. Based on the analysis of 22 loci, parameters measuring genetic variability were, for some populations, found to be among the highest reported for Artemia so far. The percentage of polymorphic loci varied from 31.8% (Piura, Peru; Buenos Aires) to 50% (Los Vilos and Salar de Atacama, Chile), while the observed heterozygosity varied from 0.025 (Piura) to 0.165 (Los Vilos, Chile). A dendrogram based on Nei's genetic distance (D) produced four major groups. The Argentinian form, A. persimilis; the San Francisco Bay strain together with samples from Brazil (Macau and Rio Grande do Norte) and Chile (Pichilemu and Salar de Atacama); two coastal populations from Chile (Los Vilos and Iquique) and the sample from Peru (Piura). These four groups have inter-group D values that are, in some cases, far above those normally associated with conspecific populations. 相似文献
18.
Annukka E. Mäkinen Anna H. Kaksonen Jaakko A. Puhakka 《Extremophiles : life under extreme conditions》2009,13(3):505-510
A thermophilic, rod-shaped, motile, Gram-positive, spore-forming bacterium strain 70BT was isolated from a geothermally active underground mine in Japan. The temperature and pH range for growth was 50–81°C (optimum
71°C) and 6.2–9.8 (optimum pH 7–7.5), respectively. Growth occurred in the presence 0–2% NaCl (optimum 1% NaCl). Strain 70BT could utilize glucose, fructose, mannose, mannitol, pyruvate, cellobiose and tryptone as substrates. Thiosulfate was used
as electron acceptor. Major whole-cell fatty acids were iso-C15:0, C16:0 DMA (dimethyl acetal), C16:0 and anteiso-C15:0. The G+C mol% of the DNA was 44.2%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the closest relatives
of strain 70BT were Thermosediminibacter oceani DSM 16646T (94% similarity) and Thermosediminibacter litoriperuensis DSM 16647 (93% similarity). The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain 70BT represents a novel species in a new genus, for which the name Thermovorax subterraneus gen. nov., sp. nov. is proposed. The type strain of Thermovorax subterraneus is 70BT (=DSM 21563 = JCM 15541). 相似文献
19.
S. Tosi N. Kostadinova E. Krumova S. Pashova V. Dishliiska B. Spassova S. Vassilev M. Angelova 《Polar Biology》2010,33(9):1227-1237
From 18 soil samples taken in the vicinity of the permanent Bulgarian Antarctic base “St. Kliment Ohridski” (62°38′29″S, 60°21′53″W)
on Livingston Island, 109 filamentous fungi were isolated on selective media. The most widespread fungal species were members
of the genera Cladosporium, Geomyces, Penicillium and Aspergillus. Other species, already recorded in Antarctic environment, were also isolated: Lecanicillium muscarium, Epicoccum nigrum and Alternaria alternata. Thirty strains demonstrating good growth were screened for antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT)
that play an important role in the defense of aerobic organisms against oxidative stress, by converting reactive oxygen species
into nontoxic molecules. Six of them showed high enzyme activity. The tested strains produced SOD with statistically significant
higher activity at 15°C than at 30°C suggesting that this enzyme is cold-active. Such SOD could be useful in medicine and
cosmetics. The best producer of cold-active SOD, Aspergillus glaucus 363, cultivated in bioreactors, demonstrated optimal growth temperature at 25°C and maximum enzyme activities at 25 and 30°C
for SOD and CAT, respectively. The electrophoretical analysis showed that the fungus possesses Cu/Zn-SOD. 相似文献
20.
Han Gil Choi Ki Hoon Lee Hyun Il Yoo Pil Jun Kang Young Sik Kim Ki Wan Nam 《Journal of applied phycology》2008,20(5):729-735
The effects of temperature, irradiance, and daylength on Sargassum horneri growth were examined at the germling and adult stages to discern their physiological differences. Temperature–irradiance
(10, 15, 20, 25, 30°C × 20, 40, 80 μmol photons m−2s−1) and daylength (8, 12, 16, 24 h) experiments were carried out. The germlings and blades of S. horneri grew over a wide range of temperatures (10–25°C), irradiances (20–80 μmol photons m−2s−1), and daylengths (8–24 h). At the optimal growth conditions, the relative growth rates (RGR) of the germlings were 21% day−1 (25°C, 20 μmol photons m−2s−1) and 13% day−1 (8 h daylength). In contrast, the RGRs of the blade weights were 4% day−1 (15°C, 20 μmol photons m−2s−1) and 5% day−1 (12 h daylength). Negative growth rates were found at 20 μmol photons m−2s−1 of 20°C and 25°C treatments after 12 days. This phenomenon coincides with the necrosis of S. horneri blades in field populations. In conclusion, we found physiological differences between S. horneri germlings and adults with respect to daylength and temperature optima. The growth of S. horneri germlings could be enhanced at 25°C, 20 μmol photons m−2s−1, and 8 h daylength for construction of Sargassum beds and restoration of barren areas. 相似文献