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1.
Deniz Özkan Deniz Yüzbaşıoğlu Fatma Ünal Serkan Yılmaz Hüseyin Aksoy 《Cytotechnology》2009,59(2):73-80
The organophosphorous insecticide acephate was tested for its ability to induce in vitro cytogenetic effect in human peripheral
lymphocytes by using the chromosomal aberrations (CAs), sister chromatid exchange (SCE) and micronuclei (MN) assay. The level
of nuclear DNA damage of acephate was evaluated by using the comet assay. Concentrations of 12.5, 25, 50, 100 and 200 μg mL−1 of acephate were used. All concentrations of acephate induced significant increase in the frequency of CAs and in the formation
of MN dose dependently (r = 0.92 at 24 h, r = 0.95 at 48 h for CAs, r = 0.87 for MN). A significant increase was observed in induction of SCE at 50, 100 and 200 μg mL−1 concentrations during 24 h treatment and at all concentrations (except 12.5 μg mL−1) during 48 h treatment period in a dose-dependent manner (r = 0.84 at 24 h, r = 0.88 at 48 h). Acephate did not affect the replicative index and cytokinesis-block proliferation index (CBPI). However,
it significantly decreased the mitotic index at all three highest concentrations (50, 100, 200 μg mL−1) for 24 h treatment and at all concentrations (except 12.5 μg mL−1) for 48 h treatment, dose-dependently (r = 0.94 at 24 h, r = 0.92 at 48 h). A significant increase in mean comet tail length was observed at 100 and 200 μg mL−1 concentrations compared with negative control in a concentration-dependent manner (r = 0.94). The mean comet tail intensity was significantly increased at only 200 μg mL−1 concentration. The present results indicate that acephate is a clastogenic, cytotoxic agent and it causes DNA damage at high
concentrations in human lymphocytes in culture. 相似文献
2.
Okeke BC 《Journal of industrial microbiology & biotechnology》2008,35(12):1571-1579
Pollution of terrestrial surfaces and aquatic systems by hexavalent chromium, Cr(VI), is a worldwide public health problem.
A chromium resistant bacterial isolate identified as Exiguobacterium sp. GS1 by 16S rRNA gene sequencing displayed high rate of removal of Cr(VI) from water. Exiguobacterium sp. GS1 is 99% identical to Exiguobacterium acetylicum. The isolate significantly removed Cr(VI) at both high and low concentrations (1–200 μg mL−1) within 12 h. The Michaelis–Menten K
m
and V
max for Cr(VI) bioremoval were calculated to be 141.92 μg mL−1 and 13.22 μg mL−1 h−1, respectively. Growth of Exiguobacterium sp. GS1 was indifferent at 1–75 μg mL−1 Cr(VI) in 12 h. At initial concentration of 8,000 μg L−1, Exiguobacterium sp. GS1 displayed rapid bioremoval of Cr(VI) with over 50% bioremoval in 3 h and 91% bioremoval in 8 h. Kinetic analysis
of Cr(VI) bioremoval rate revealed zero-order in 8 h. Exiguobacterium sp. GS1 grew and significantly reduced Cr(VI) in cultures containing 1–9% salt indicating high salt tolerance. Similarly
the isolate substantially reduced Cr(VI) over a wide range of temperature (18–45 °C) and initial pH (6.0–9.0). The T
opt and initial pHopt were 35–40 °C and 7–8, respectively. Exiguobacterium sp. GS1 displayed a great potential for bioremediation of Cr(VI) in diverse complex environments. 相似文献
3.
Samia Oueslati Najoua Karray-Bouraoui Houneïda Attia Mokded Rabhi Riadh Ksouri Mokhtar Lachaal 《Acta Physiologiae Plantarum》2010,32(2):289-296
Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions
of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses.
Physiological and biochemical parameters were assessed in the plant organs after 2 weeks of salt treatment with 25, 50, 75
and 100 mM NaCl. Results showed that, growth was reduced even by 25 mM, and salt effect was more pronounced in shoots (leaves
and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline
conditions. Leaf and root guaiacol peroxidase activity showed an increase by different concentration of NaCl, but superoxide
dismutase activity in the same organs showed a slight modification in NaCl-treated leaves and roots. Moreover, polyphenol
contents and antioxidant activity were analysed in M. pulegium leaves and roots under salt constraint. The analysis showed an increase of total polyphenol content (2.41–8.17 mg gallic
acid equivalent g−1 dry weight) in leaves. However, methanol extract of leaves at 100 mM NaCl displayed the highest DPPH· scavenging ability
with the lowest IC50 value (0.27 μg ml−1) in comparison with control which exhibited IC50 equal to 0.79 μg ml−1. 相似文献
4.
C. Sivapathasekaran Palashpriya Das Soumen Mukherjee J. Saravanakumar Mahitosh Mandal Ramkrishna Sen 《International journal of peptide research and therapeutics》2010,16(4):215-222
A marine Bacillus circulans DMS-2 was able to grow and produce biosurfactant on glucose mineral salts medium (GMSM) with a reduction in the surface tension
up to 27 mN m−1. The microorganism produced 1.64 ± 0.1 g l−1 of crude biosurfactant. The lipopeptide nature of the produced biosurfactant was confirmed by primulin and ninhydrin assays
using High Performance Thin Layer Chromatography (HPTLC). Preparative thin layer chromatography (TLC) was performed to purify
the lipopeptides from the crude biosurfactant. The critical micelle concentrations (CMC) of the crude and purified products
were found to be 90 and 40 mg l−1 respectively. Fourier transform infrared spectrophotometer (FTIR) and matrix assisted laser desorption/ionization time of
flight (MALDI-ToF) mass spectral analysis revealed the identity of the produced lipopeptides as surfactin (m/z 1,023 Da) and fengycin (m/z 1,495 Da) isoforms. The purified marine lipopeptides displayed a significant antiproliferative activity against the human
colon cancer cell lines HCT-15 (IC50 80 μg ml−1) and HT-29 (IC50 120 μg ml−1). 相似文献
5.
Meyyappan Arumugam Anindita Mitra Parasuraman Jaisankar Shreya Dasgupta Tuhinadri Sen Ratan Gachhui Ujjal Kumar Mukhopadhyay Joydeep Mukherjee 《Applied microbiology and biotechnology》2010,86(1):109-117
A marine actinobacterium isolated from the Bay of Bengal, India and previously found to be producing an antimicrobial and
cytotoxic terpenoid was further investigated for antimicrobial metabolites. The bacterium was preliminarily identified as
a new species of the genus Streptomyces (strain MS1/7). The cell-free culture broth was extracted with n-butanol and purified using silica gel column chromatography and high-performance liquid chromatography. Molecular characterization
was done using ESI mass, IR and 1H and 13C NMR spectrometry. 2-Allyloxyphenol (MW 150; C9H10O2), a synthetic drug and chemical intermediate, was obtained as a natural product for the first time. Serendipitous natural
occurrence provided new insights into the synthetic molecule. 2-Allyloxyphenol was found to be inhibitory to 21 bacteria and
three fungi in the minimum range 0.2–1.75 mg mL−1 determined by agar dilution method. 2-Allyoxyphenol possesses strong antioxidant property (IC50 22 μg mL−1, measured by 1, 1-diphenyl-2-picryl hydrazyl scavenging activity). Hydroxyl and allyloxy groups in 2-allyloxyphenol were
responsible for antimicrobial and antioxidant activities. 2-Allyloxyphenol has marked resemblance to smoky aroma and is two
to three times more active as an antimicrobial than some commercial smoke-flavour compounds. Absence of hemolytic toxicity,
potential carcinogenicity, cytotoxicity and reports of toxic reactions in literature suggest possible application of 2-allyloxyphenol
as a food preservative and an oral disinfectant. 相似文献
6.
Thalli of epiphytic lichen Hypogymnia physodes (L.) Nyl. and terricolous Cladonia furcata (Huds.) Schrad., collected from an area with background arsenic concentrations, were exposed to 0, 0.1, 1 and 10 μg mL−1 arsenate (As(V)) solutions for 24 h. After exposure they were kept in the metabolically active state for 0, 24 and 48 h in
a growth chamber. In the freeze dried samples glutathione (GSH), glutathione disulphide (GSSG), cysteine (Cys) and cystine
were analysed and induction of phytochelatin (PC) synthesis measured by reversed-phase high-performance liquid chromatography
in combination with fluorescence detection or UV spectrometry. Total arsenic content in thalli was measured by instrumental
neutron activation analysis (INAA). In H. physodes, which contained higher amounts of arsenic compared to C. furcata, total glutathione content significantly decreased in samples exposed to 10 μg mL−1 As(V), whereas in C. furcata a significant increase was observed. In both species PC synthesis was induced in thalli exposed to 10 μg mL−1. 相似文献
7.
Micheline Cristiane Rocha de Souza Cybelle Teixeira Marques Celina Maria Guerra Dore Fernando Roberto Ferreira da Silva Hugo Alexandre Oliveira Rocha Edda Lisboa Leite 《Journal of applied phycology》2007,19(2):153-160
The in vitro antioxidant activities of the following six sulfated polysaccharides were investigated: iota, kappa and lambda carrageenans,
which are widely used in the food industry, fucoidan (homofucan) from the edible seaweed Fucus vesiculosus and fucans (heterofucans) F0.5 and F1.1 from the seaweed Padina gymnospora. With respect to the inhibition of superoxide radical formation, fucoidan had an IC50 (the half maximal inhibitory concentration) of 0.058 mg·mL−1, while the IC50 for the kappa, iota and lambda carrageenans were 0.112, 0.332 and 0.046 mg·mL−1, respectively. All of the samples had an inhibitory effect on the formation of hydroxyl radicals. The results of peroxidation
tests showed that fucoidan had an IC50 of 1.250 mg·mL−1 and that the kappa, iota and lambda carrageenans had an IC50 of 2.753 and 2.338 and 0.323 mg·mL−1, respectively. Fucan fractions showed low antioxidant activity relative to fucoidan. These results clearly indicate the beneficial
effect of algal polysaccharides as antioxidants. 相似文献
8.
This study was designed to identify rhizobial strains specific to greengram expressing higher tolerance against insecticides,
fipronil and pyriproxyfen, and synthesizing plant growth regulators even amid insecticide-stress. Of the 50 bradyrhizobial
isolates, the Bradyrhizobium sp. strain MRM6 showed tolerance up to 1,600 μg mL−1 against each of fipronil and pyriproxyfen. The tolerant Bradyrhizobium sp. (vigna) produced plant growth promoting substances in substantial amounts, both in the presence and absence of insecticides. The
strain MRM6 was further used to investigate its impact on greengram grown in soils treated with 200 (the recommended dose),
400 and 600 μg kg−1 soil of fipronil and 1,300 (the recommended dose), 2,600 and 3,900 μg kg−1 soil of pyriproxyfen. Fipronil at 600 μg kg−1 soils and pyriproxyfen at 3,900 μg kg−1 soils had greatest toxic effects and decreased plant biomass, symbiotic efficiency, nutrient uptake and seed yield of greengram
plants. The Bradyrhizobium sp. (vigna) inoculant when used with fipronil and pyriproxyfen significantly increased the measured parameters compared to the plants
grown in soils treated solely with the same concentration of each insecticide. This study inferred that the Bradyrhizobium sp. (vigna) strain MRM6 may be exploited as bio-inoculant to increase the productivity of greengram exposed to insecticide-stressed
soils. 相似文献
9.
A. E. Solovchenko I. Khozin-Goldberg Z. Cohen M. N. Merzlyak 《Journal of applied phycology》2009,21(3):361-366
The relationships between pigment (carotenoid and chlorophyll) content with accumulation of total fatty acids (TFA) and arachidonic
acid (AA) were studied in the green microalga Parietochloris incisa (Trebouxiophyceae, Chlorophyta) grown under different PFDs (35, 200, and 400 μmol photons m−2 s−1) and nitrogen availabilities. The growth of P. incisa under higher light and nitrogen deficiency was accompanied by accumulation of FA, an increase in carotenoid and a decline
in chlorophyll content. It was found that the carotenoid-to-chlorophyll ratio (but not the individual pigment content) correlates
closely with the volumetric content of both TFA and AA. Analysis of scattering-compensated absorption spectra of P. incisa suspensions revealed their tight relationship in the blue-green range of the spectrum with the carotenoid-to-chlorophyll
ratio, TFA, and AA content. These findings allowed the development of algorithms for the non-destructive assay of TFA and
AA in cell suspensions in the ranges of 0.09–3.04 and 0.04–1.7 μg mL−1, with accuracy of 0.06 and 0.01 μg mL−1, respectively, via analytically measured carotenoid-to-chlorophyll ratio and using the ratio of absorption coefficients at
510 and 678 nm, with accuracy of 0.07 and 0.02 μg mL−1, respectively. The feasibility of obtaining essential spectral information concerning the physiological condition of P. incisa using a standard spectrophotometer is also shown. 相似文献
10.
Santiago IF Alves TM Rabello A Sales Junior PA Romanha AJ Zani CL Rosa CA Rosa LH 《Extremophiles : life under extreme conditions》2012,16(1):95-103
A total of 564 isolates of endophytic fungi were recovered from the plants Deschampsia antarctica and Colobanthus quitensis collected from Antarctica. The isolates were screened against parasites Leishmania amazonensis and Trypanosoma cruzi and against the human tumour cell lines. Of the 313 fungal isolates obtained from D. antarctica and 251 from C. quitensis, 25 displayed biological activity. Nineteen extracts displayed leishmanicidal activity, and six inhibited the growth of at
least one tumour cell line. These fungi belong to 19 taxa of the genera Alternaria, Antarctomyces, Cadophora, Davidiella, Helgardia, Herpotrichia, Microdochium, Oculimacula, Phaeosphaeria and one unidentified fungus. Extracts of 12 fungal isolates inhibited the proliferation of L. amazonesis at a low IC50 of between 0.2 and 12.5 μg ml−1. The fungus Phaeosphaeria herpotrichoides displayed only leishmanicidal activity with an IC50 of 0.2 μg ml−1, which is equivalent to the inhibitory value of amphotericin B. The extract of Microdochium phragmitis displayed specific cytotoxic activity against the UACC-62 cell line with an IC50 value of 12.5 μg ml−1. Our results indicate that the unique angiosperms living in Antarctica shelter an interesting bioactive fungal community
that is able to produce antiprotozoal and antitumoral molecules. These molecules may be used to develop new leishmanicidal
and anticancer drugs. 相似文献
11.
The degradation potential of trichloroethene by the aerobic methane- and ammonia-oxidizing microorganisms naturally associated
with wetland plant (Carex comosa) roots was examined in this study. In bench-scale microcosm experiments with washed (soil free) Carex comosa roots, the activity of root-associated methane- and ammonia-oxidizing microorganisms, which were naturally present on the
root surface and/or embedded within the roots, was investigated. Significant methane and ammonia oxidation were observed reproducibly
in batch reactors with washed roots incubated in growth media, where methane oxidation developed faster (2 weeks) compared
to ammonia oxidation (4 weeks) in live microcosms. After enrichment, the methane oxidizers demonstrated their ability to degrade
150 μg l−1 TCE effectively at 1.9 mg l−1 of aqueous CH4. In contrast, ammonia oxidizers showed a rapid and complete inhibition of ammonia oxidation with 150 μg l−1 TCE at 20 mg l−1 of NH4
+-N, which may be attributed to greater sensitivity of ammonia oxidizers to TCE or its degradation product. No such inhibitory
effect of TCE degradation was detected on methane oxidation at the above experimental conditions. The results presented here
suggest that microorganisms associated with wetland plant roots can assist in the natural attenuation of TCE in contaminated
aquatic environments. 相似文献
12.
The influence of phytohormones, salicylic acid (SA) and methyl jasmonate (MJ) on the antioxidant systems in Haematococcus
pluvialis was investigated. Both SA and MJ at 500 μM concentration reduced the growth of alga with salicylic acid, having more pronounced
effect. Carotenoid and chlorophyll contents were decreased by SA and increased by MJ. Salicylic acid (100 μM) increased astaxanthin
content to 6.8-fold under low light (30 μmol m−2 s−1), while MJ (10 μM) showed marginal increase in astaxanthin. Salicylic acid (500 μM) increased superoxide dismutase activity
to 4.5- and 3.3-fold and ascorbate peroxidase (APX) activity to 15.5- and 7.1-fold under low and high light, respectively.
Methyl jasmonate increased catalase activity (1.4-fold) under high light and APX activity (5.4-fold) under low light. Different
mechanism of oxidative stress induced antioxidant production may be the plausible reason for this varied response for salicylic
acid and methyl jasmonate. Higher concentrations of SA and MJ inhibited astaxanthin accumulation by different mechanisms either
by scavenging the free radicals or by increasing primary carotenoids production. At lower concentrations, these phytohormones
could be used for elicitation of secondary carotenoid production. 相似文献
13.
Laura Pinilla Rodrigo Torres Claudia Ortiz 《World journal of microbiology & biotechnology》2011,27(11):2521-2528
Two wild strains of Zymomonas mobilis were isolated (named as ML1 and ML2) from sugar cane molasses obtained from different farms of Santander, Colombia. Initially,
selection of the best ethanol-producer strains was carried out using ethanol production parameters obtained with a commercial
strain Z. mobilis DSM 3580. Three isolated strains were cultivated in a culture medium containing yeast extract, peptone, glucose and salts,
at pH 6 and 32°C with stirring rate of 65 rpm during 62 h. The best results of ethanol production were obtained with the native
strain ML1, reaching a maximum ethanol concentration of 79.78 g l−1. ML1 and ML2 strains were identified as Z.
mobilis, according to the morphology, biochemical tests and molecular characterization by PCR of specific DNA sequences from Z. mobilis. Subsequently, the effect of different nitrogen sources on production of ethanol was evaluated. The best results were obtained
using urea at a 0.73 g/l. In this case, maximum concentration of ethanol was 83.81 g l−1, with kinetic parameters of yield of ethanol on biomass (YP/X) = 69.01(g g−1), maximum volumetric productivity of ethanol (Qpmax) = 2.28 (g l−1 h−1), specific productivity of ethanol (qP) = 3.54 (h−1) and specific growth rate (μ) = 0.12 h−1. Finally, we studied the effect of different culture conditions (pH, temperature, stirring, C/N ratio) with a Placket-Burman′s
experimental design. This optimization indicated that the most significant variables were temperature and stirring. In the
best culture conditions a significant increase in all variables of response was achieved, reaching a maximum ethanol concentration
of 93.55 g l−1. 相似文献
14.
Y Tang J Tong Y Zhang L Wang S Hu W Li Y Lv 《World journal of microbiology & biotechnology》2012,28(1):397-400
In order to provide guidance for selecting suitable heterogenous gene that can efficiently enhance toxicity or broaden insecticidal
spectrum of Cry1Ac through fusion expression, two hybrid cry1Acs fused with chitinase-encoding gene tchiB and neurotoxin gene hwtx-1 respectively were constructed and their toxicities were compared. A Bacillus thuringiensis strain harboring the cry1Ac gene in vector pHT315 was used as control. Bioassay revealed that LC50 (after 72 h) of Cry1Ac protoxin was 41.01 μg mL−1, while the hybrid cry1Acs fused with tchiB and hwtx-1 were 4.89 and 23.14 μg mL−1, which were 8.23- and 1.77-fold higher than Cry1Ac protoxin in terms of relative toxicity respectively. Both fusion crystals
had a higher toxicity than the original Cry1Ac protein and the toxicity of hybrid cry1Acs fused with hwtx-1 experienced a more significant increase than that fused with tchiB. 相似文献
15.
Identification of QTL underlying isoflavone contents in soybean seeds among multiple environments 总被引:3,自引:0,他引:3
Guoliang Zeng Dongmei Li Yingpeng Han Weili Teng Jian Wang Liquan Qiu Wenbin Li 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(8):1455-1463
Soybean isoflavones are valued in certain medicines, cosmetics, foods and feeds. Selection for high-isoflavone content in
seeds along with agronomic traits is a goal of many soybean breeders. The aim of the study was to identify the quantitative
trait loci (QTL) underlying seed isoflavone content in soybean among seven environments in China. A cross was made between
‘Zhongdou 27’, a soybean cultivar with higher mean isoflavone content in the seven environments (daidzein, DZ, 1,865 μg g−1; genistein, GT, 1,614 μg g−1; glycitein, GC, 311 μg g−1 and total isoflavone, TI, 3,791 μg g−1) and ‘Jiunong 20’, a soybean cultivar with lower isoflavone content (DZ, 844 μg g−1; GT, 1,046 μg g−1; GC, 193 μg g−1 and TI, 2,061 μg g−1). Through single-seed-descent, 130 F5-derived F6 recombinant inbred lines were advanced. A total of 99 simple-sequence repeat markers were used to construct a genetic linkage
map. Seed isoflavone contents were analyzed using high-performance liquid chromatography for multiple years and locations
(Harbin in 2005, 2006 and 2007, Hulan in 2006 and 2007, and Suihua in 2006 and 2007). Three QTL were associated with DZ content,
four with GT content, three with GC content, and five with TI content. For all QTL detected the beneficial allele was from
Zhongdou 27. QTL were located on three (DZ), three (GC), four (GT) and five (TI) molecular linkage groups (LG). A novel QTL
was detected with marker Satt144 on LG F that was associated with DZ (0.0014 > P > 0.0001, 5% < R
2 < 11%; 254 < DZ < 552 μg g−1), GT (0.0027 > P > 0.0001; 4% < R
2 < 9%; 262 < GT < 391 μg g−1), and TI (0.0011 > P > 0.0001; 4% < R
2 < 15%; 195 < TI < 871 μg g−1) across the various environments. A previously reported QTL on LG M detected by Satt540 was associated with TI across four
environments and TI mean (0.0022 > P > 0.0001; 3% < R
2 < 8%; 182 < TI < 334 μg g−1) in China. Because both beneficial alleles were from Zhongdou 27, it was concluded that these two QTL would have the greatest
potential value for marker-assisted selection for high-isoflavone content in soybean seed in China.
G. Zeng, D. Li and Y. Han have equal contributions to the paper. 相似文献
16.
This study was undertaken to explore the role of Trichoderma sp. in phosphate (P) solubilization and antagonism against fungal phytopathogens. All fungal isolates (SE6, KT6, KT28, and BRT11) and a standard culture of T. harzianum (Th-std) were able to antagonize two fungal phytopathogens (Sclerotium rolfsii and Rhizoctonia solani) of chickpea (Cicer arietinum L.) wilt complex. Transmission electron microscopic studies (TEM) further confirmed ultra-cytological changes in the sclerotia
of S. rolfsii parasitized by Trichoderma sp. All fungal cultures exhibited production of NH3 and siderophore, but only BRT11, SE6, and Th-std could produce HCN. Among all the cultures tested, isolate KT6 was found to be most effective for solubilization of ferric phosphate releasing 398.4 μg ml−1 phosphate while isolates BRT11 and SE6 showed more potential for tricalcium phosphate (TCP) solubilization releasing 449.05 and 412.64 μg ml−1 phosphate, respectively, in their culture filtrates. Part of this study focused on the influence of abiotic stress conditions
such as pH, temperature, and heavy metal (cadmium) on phosphate (TCP) solubilizing efficiency. Two selected cultures KT6 and T. harzianum retained their P solubilizing potential at varying concentrations of cadmium (0–1000 μg ml−1). Isolate KT6 and standard culture of T. harzianum released 278.4 and 287.6 μg ml−1 phosphate, respectively, at 1000 μg ml−1cadmium. Maximum solubilization of TCP was obtained at alkaline pH and at 28°C temperature. Isolate BRT11 was found most alkalo-tolerant releasing 448.0 μg ml−1 phosphate at pH 9. 相似文献
17.
Chlorophyll-a (chl-a) and carotenoid pigments of the zooxanthellate octocoral Sinularia flexibilis were analyzed using high performance liquid chromatography following exposure to three light intensities for over 30 days.
From the coral fragments located at different light intensities, a total carotenoid of >41 μg g−1 dry weight, including peridinin, xanthophylls (likely diadinoxanthin + diatoxanthin), and chl-a as the most abundant pigments, with minor contents of astaxantin and β-carotene were detected. The whole content of chl-a weighed 5 μg g−1 dry weight in all coral colonies. Chl-a and carotenoids contributed 11.2% and 88.2%, respectively, to all pigments detected, and together accounted for 99.4% of
the total pigments present. The highest contents of carotenoids and chl-a was observed in the coral grafts placed in an irradiance of 100 μmol quanta m−2 s−1; they showed lower ratios of total carotenoids: chl-a compared to those exposed to 400 μmol quanta m−2 s−1 after >30 days of incubation. The ratios of peridinin and xanthophylls with respect to chl-a from the colonies at 400 μmol quanta m−2 s−1 were approximately double those observed at irradiances of 100 and 200 μmol quanta m−2 s−1. Partial quantification of pigments in this study showed that the carotenoids of S. flexibilis showed a decrease at irradiances above 100 μmol quanta m−2 s−1, with the exception of an increase in β-carotene at 200 μmol quanta m−2 s−1. 相似文献
18.
Polysaccharides extracted from Ulva pertusa Kjellm (Chlorophyta) are a group of sulfated heteropolysaccharides, the ulvans. In this study, different molecular weight
ulvans were prepared by H2O2 degradation and their antioxidant activities investigated including superoxide and hydroxyl radical scavenging activity,
reducing power and metal chelating ability. The molecular weights of natural and degraded ulvans were 151.7, 64.5, 58.0, and
28.2 kDa, respectively, as determined by high performance gel permeation chromatography. Among the four samples, U3 (the lowest molecular weight sample) showed significant inhibitory effects on superoxide and hydroxyl radicals with IC50 values of 22.1 μ g mL−1 and 2.8 mg mL−1; its reducing power and metal chelating ability were also the strongest among the four samples. All the other samples also
demonstrated strong activity against superoxide radicals. The results indicated that molecular weight had a significant effect
on the antioxidant activity of ulvan with low molecular weight ulvan having stronger antioxidant activity. 相似文献
19.
Liu J Zhang Z Liu Z Zhu H Dang H Lu J Cui Z 《Marine biotechnology (New York, N.Y.)》2011,13(5):837-844
The aim of this work was to optimize the fermentation parameters in the shake-flask culture of marine bacterium Wangia sp. C52 to increase cold-adapted amylase production using two statistical experimental methods including Plackett–Burman
design, which was applied to find the key ingredients for the best medium composition, and response surface methodology, which
was used to determine the optimal concentrations of these components. The results showed starch, tryptone, and initial pH
had significant effects on the cold-adapted amylase production. A central composite design was then employed to further optimize
these three factors. The experimental results indicated that the optimized composition of medium was 6.38 g L−1 starch, 33.84 g L−1 tryptone, 3.00 g L−1 yeast extract, 30 g L−1 NaCl, 0.60 g L−1 MgSO4 and 0.56 g L−1 CaCl2. The optimized cultivation conditions for amylase production were pH 7.18, a temperature of 20°C, and a shaking speed of
180 rpm. Under the proposed optimized conditions, the amylase experimental yield (676.63 U mL−1) closely matched the yield (685.60 U mL−1) predicted by the statistical model. The optimization of the medium contributed to tenfold higher amylase production than
that of the control in shake-flask experiments. 相似文献
20.
Irzykowska L Bocianowski J Waśkiewicz A Weber Z Karolewski Z Goliński P Kostecki M Irzykowski W 《Journal of applied genetics》2012,53(2):237-247
Thirty single-spore isolates of a toxigenic fungus, Fusarium oxysporum, were isolated from asparagus spears and identified by species-specific polymerase chain reaction (PCR) and translation elongation
factor 1-α (TEF) sequence analysis. In the examined sets of F. oxysporum isolates, the DNA sequences of mating type genes (MAT) were identified. The distribution of MAT idiomorph may suggest that MAT1-2 is a predominant mating type in the F. oxysporum population. F. oxysporum is mainly recognised as a producer of moniliformin—the highly toxic secondary metabolite. Moniliformin content was determined
by high-performance liquid chromatography (HPLC) analysis in the range 0.05–1,007.47 μg g−1 (mean 115.93 μg g−1) but, also, fumonisin B1 was detected, in the concentration range 0.01–0.91 μg g−1 (mean 0.19 μg g−1). There was no association between mating types and the mycotoxins biosynthesis level. Additionally, a significant intra-species
genetic diversity was revealed and molecular markers associated with toxins biosynthesis were identified. 相似文献