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1.
Tatjana Vujović Đurđina Ružić Radosav Cerović Gordana Šurlan Momirović 《Plant Growth Regulation》2010,61(3):265-275
Adventitious shoot regeneration from leaves of blackberry cultivar Čačanska Bestrna was examined using 30 different combinations
of treatment. Young, fully expanded leaves taken from in vitro proliferating shoots were cultured on Murashige and Skoog (MS)
medium containing either N
6-benzylaminopurine (BAP) (2.0 mg l−1) or thidiazuron (TDZ) (1.0 and 2.0 mg l−1) alone, or either of them combined with indol-3-butyric acid (IBA), α-naphthalene acetic acid (NAA) and 2,4-dichlorophenoxyacetic
acid (2,4-D) at different concentrations (0.1, 1.0 and 2.0 mg l−1). Indirect shoot formation was observed in 12 different treatments, though the efficacy varied greatly among types and concentrations
of plant growth regulators. TDZ at 1.0 mg l−1, applied either alone or combined with IBA, was significantly more effective than BAP in inducing shoot regeneration. The
highest regeneration rate (41.66%) was obtained on medium containing TDZ alone. Cytological, flow cytometry and isozyme analyses
were used for screening of genetic stability/instability in regenerants. Cytological study, based on chromosome counts in
root tip meristems, and flow cytometry analysis indicated that adventitious shoots of Čačanska Bestrna are tetraploid with
2n = 4x = 28 as well as those derived from axillary buds. However, a study conducted on the peroxidase patterns of the different
blackberry regenerating lines showed differences between some lines and control plants (in vivo plants and micropropagated
plants). These differences were visible with 3,3′,5,5′-tetramethylbenzidine (TMBZ) as hydrogenous donor for peroxidase detection. 相似文献
2.
Biomass and aboveground net primary production (ANPP) in a monospecific pioneer stand of a mangrove Kandelia obovata (S., L.) Yong were quantified. The estimated biomasses in leaves, branches, stems, roots, aboveground and total were 5.61
(3.68%), 28.8 (18.9%), 46.1 (30.2%), 71.8 (47.2%), 80.5 (52.8%) and 152 Mg ha−1 (100%), respectively. Stem phytomass increment per tree was estimated using allometric relationships and stem analysis. Stem
volume without bark of harvested trees showed a strong allometric relationship with D
0.12
H (D
0.1, diameter at a height of one-tenth of tree height H) (R
2 = 0.924). Annual stem volume increment per tree showed a strong allometric relationship with D
0.12
H (R
2 = 0.860). Litterfall rate ranges from 3.87 to 56.1 kg ha−1 day−1 for leaves and 0.177 to 46.2 kg ha−1 day−1 for branches. Seasonal changes of litterfall rate were observed, which showed a peak during wet season (August–September).
Total annual litterfall was estimated as 10.6 Mg ha−1 year−1, in which 68.2% was contributed by the leaves. The ANPP in the K. obovata stand was 29.9–32.1 Mg ha−1 year−1, which is ca. 2.8–3.0 times of annual litterfall. The growth efficiency (aboveground biomass increment/LAI) was 5.35–5.98 Mg ha−1 year−1. The low leaf longevity (9.3 months) and high growth efficiency of K. obovata makes it a highly productive mangrove species. 相似文献
3.
The possible ameliorative effects of quercetin on soybean [Glycine max (L.) Merr.] leaves exposed to UV-B radiation were conducted in greenhouse. The symmetrical leaves supplied with quercetin
solution (0.2%, 1%) were exposed to UV-B radiation (0, 3.5, 6.5 kJ m−2 d−1). 0.2% quercetin ameliorated leaf photosynthesis, improved leaf water content (LWC), and decreased lipid oxidation. The unfavorable
effect on photosynthetic parameter was displayed in 1% quercetin treatment. The effect of quercetin on phenylalanine ammonia
lyase (PAL) activity varied with the quercetin concentration, UV-B radiation intensity and leaf development. In the later
development polyphenol oxidase (PPO) activity was increased significantly by quercetin treatments. We suggested that quercetin
with suitable concentration could serve as UV-B protective agent partly due to its antioxidant capacity. 相似文献
4.
Bifidobacterium longum grew at 65 L pilot scale of the membrane bioreactor (MBR), externally fitted with ceramic membrane (0.7 m2). Cell mass at the MBR reached 22.18 g L−1 as dry cell weight in 12 h, which is 8.44 times higher than cell mass attained at the vial culture. The growth rate in the
vial culture was μ = 0.385 h− and at the batch culture was μ = 1.13 h− in the exponential period and μ = 0.31 h−1 in the stationary period. In the fed-batch mode was μ = 1.102 h−1 for 6 h with inoculation and declined to μ = 0.456 h−1 with feeding of feed medium. The growth rate at the MBR was μ = 0.134 h−1. The number of viable cells was 6.01 × 1012 cfu L−1 at the batch culture, but increased to 1.15 × 1014 cfu L−1 at the MBR culture. The specific growth rate of viable cell number (colony-forming units per liter, per hour) improved by
6.01 times from the batch to the MBR culture. The wall shear stress mainly generated by the pump, and the membrane incorporated
into the MBR was controlled during the cultivation at the MBR. The viability of B. longum declined to under 10% in the first 2 weeks of the 4-week stability test (40°C) as B. longum was exposed to over wall shear stress 713 Pa, but the viability improved to 30–40% in wall shear stress of 260 Pa or STR
culture. The loss in the cell viability can be saved by managing with wall shear stress during the cultivation at the MBR. 相似文献
5.
Basharat Ali Anjum Nasim Sabri Shahida Hasnain 《World journal of microbiology & biotechnology》2010,26(8):1379-1384
Potential of non-symbiotic plant growth promoting rhizobacteria (PGPR) to influence the endogenous indole-3-acetic acid (IAA)
content and growth of Vigna radiata (L.) was evaluated. The bacterial strains used belonged to Pseudomonas, Escherichia, Micrococcus and Staphylococcus genera. All strains were able to produce IAA (1.16–8.22 μg ml−1) in the presence of 1,000 μg ml−1 of l-tryptophan as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. However, strains exhibited variable
results for other growth promoting traits such as phosphate solubilization and siderophore or hydrogen cyanide production.
Bacterial IAA production showed significant positive correlation with endogenous IAA content of roots (r = 0.969; P = 0.01) and leaves (r = 0.905; P = 0.01) under axenic conditions. Bacterization of V. radiata seeds significantly enhanced shoot length (up to 48.10%) and shoot fresh biomass (up to 43.80%) under fully axenic conditions.
Bacterial strains applied under wire-house conditions also improved shoot length, number of pods, and grain weight up to 58,
65, and 17.15% respectively, over control. Hence, free living (non-symbiotic) PGPR have the ability to influence endogenous
IAA content and growth of leguminous plants. 相似文献
6.
Greice S. Borghetti Ivana S. Lula Ruben D. Sinisterra Valquiria L. Bassani 《AAPS PharmSciTech》2009,10(1):235-242
The present study was designed to investigate the influence of operating conditions (temperature, stirring time, and excess
amount of quercetin) on the complexation of quercetin with β-cyclodextrin using a 23 factorial design. The highest aqueous solubility of quercetin was reached under the conditions 37°C/24 h/6 mM of quercetin.
The stoichiometric ratio (1:1) and the apparent stability constant (Ks = 230 M−1) of the quercetin/β-cyclodextrin complex were determined using phase-solubility diagrams. The semi-industrial production
of a 1:1 quercetin/β-cyclodextrin solid complex was carried out in aqueous solution followed by spray-drying. Although the
yield of the spray-drying process was adequate (77%), the solid complex presented low concentration of quercetin (0.14%, w/w) and, thus, low complexation efficiency. The enhancement of aqueous solubility of quercetin using this method was limited
to 4.6-fold in the presence of 15 mM of β-cyclodextrin. Subsequently, an inclusion complex was prepared via physical mixture
of quercetin with β-cyclodextrin (molar ratio of 1:1 and quercetin concentration of 23% (w/w)) and characterized using infrared spectroscopy, differential scanning calorimetry, nuclear magnetic resonance spectroscopy,
and scanning electron microscopy analyses. The enhancement of aqueous solubility of quercetin using this method was 2.2-fold,
similar to that found in the complex prepared in aqueous solution before the spray-drying process (2.5-fold at a molar ratio
of 1:1, i.e., 6 mM of quercetin and 6 mM of β-cyclodextrin). 相似文献
7.
Kaarel Adamberg Petri-Jaan Lahtvee Kaspar Valgepea Kristo Abner Raivo Vilu 《Antonie van Leeuwenhoek》2009,95(3):219-226
Quasi steady state growth of Lactococcus
lactis IL 1403 was studied in glucose-limited A-stat cultivation experiments with acceleration rates (a) from 0.003 to 0.06 h−2 after initial stabilization of the cultures in chemostat at D = 0.2–0.3 h−1. It was shown that the high limit of quasi steady state growth rate depended on the acceleration rate used—at an acceleration
rate 0.003 h−2 the quasi steady state growth was observed until μ
crit = 0.59 h−1, which is also the μ
max value for the culture. Lower values of μ
crit were observed at higher acceleration rates. The steady state growth of bacteria stabilized at dilution rate 0.2 h−1 was immediately disrupted after initiating acceleration at the highest acceleration rate studied—0.06 h−2. Observation was made that differences [Δ(μ − D)] of the specific growth rates from pre-programmed dilution rates were the lowest using an acceleration rate of 0.003 h−2 (< 4% of preset changing growth rate). The adaptability of cells to follow preprogrammed growth rate was found to decrease
with increasing dilution rate—it was shown that lower acceleration rates should be applied at higher growth rates to maintain
the culture in the quasi steady state. The critical specific growth rate and the biomass yields based on glucose consumption
were higher if the medium contained S
0 = 5 g L−1 glucose instead of S
0 = 10 g L−1. It was assumed that this was due to the inhibitory effect of lactate accumulating at higher concentrations in the latter
cultures. Parallel A-stat experiments at the same acceleration and dilution rates showed good reproducibility—Δ(μ − D) was less than 5%, standard deviations of biomass yields per ATP produced (Y
ATP), and biomass yields per glucose consumed (Y
XS) were less than 15%. 相似文献
8.
9.
Soha E. Mostafa Nabila S. Karam Rida A. Shibli Feras Q. Alali 《Plant Cell, Tissue and Organ Culture》2010,103(1):111-121
A protocol for micropropagation of Arbutus andrachne from seeds was developed. Results indicated that none of the seeds cultured on Murashige and Skoog (MS) medium, with or without
plant growth regulators (PGRs), germinated. Seeds soaked in 250 mg l−1 gibberellic acid (GA3) at 4°C for 3 days, then cultured on water-agar medium containing 2.0 mg l−1 GA3 exhibited 80–100% germination and developed into usable seedlings. Shoot proliferation was tested on MS or B5 medium containing
different concentrations of cytokinin. No shoot proliferation was observed on PGR-free medium. Proliferation was more successful
on MS than on B5 medium. On both media, the most successful proliferation was obtained using zeatin as a cytokinin type. Rooting
was tested on MS medium containing different concentrations of auxin. Rooting failed on PGR-free medium and on medium containing
indole-3-acetic acid (IAA), 0.25 or 0.5 mg l−1 indole-3-butyric acid (IBA), or 0.25, 0.5 or 2.0 mg l−1 α-naphthaleneacetic acid (NAA). Rooting (40%) was most successful with 1.0 mg l−1 NAA. Rooted plantlets exhibited 80% survival in all mixtures of peatmoss and perlite, and acclimatized plants were successfully
grown in the greenhouse. Quantitative analysis of arbutin performed on in vivo and in vitro leaves using high-performance
liquid chromatography (HPLC) revealed that in vivo leaves contained higher arbutin content (0.3–0.81% w/w) than in vitro leaves
(0.09% w/w). The highest yield of arbutin in vivo was detected in leaves collected in August, and the lowest yield in leaves
collected in December. 相似文献
10.
Kameshnee Naidoo Manimaran Ayyachamy Kugen Permaul Suren Singh 《Bioprocess and biosystems engineering》2009,32(5):689-695
Xanthomonas campestris pv phaseoli produced an extracellular endoinulinase (9.24 ± 0.03 U mL−1) in an optimized medium comprising of 3% sucrose and 2.5% tryptone. X. campestris pv. phaseoli was further subjected to ethylmethanesulfonate mutagenesis and the resulting mutant, X. campestris pv. phaseoli KM 24 demonstrated inulinase production of 22.09 ± 0.03 U mL−1 after 18 h, which was 2.4-fold higher than that of the wild type. Inulinase production by this mutant was scaled up using
sucrose as a carbon source in a 5-L fermenter yielding maximum volumetric (21,865 U L−1 h−1) and specific (119,025 U g−1 h−1) productivities of inulinase after 18 h with an inulinase/invertase ratio of 2.6. A maximum FOS production of 11.9 g L−1 h−1 and specific productivity of 72 g g−1 h−1 FOS from inulin were observed in a fermenter, when the mutant was grown on medium containing 3% inulin and 2.5% tryptone.
The detection of mono- and oligosaccharides in inulin hydrolysates by TLC analysis indicated the presence of an endoinulinase.
This mutant has potential for large-scale production of inulinase and fructooligosaccharides. 相似文献
11.
Malaysia is the world’s leading producer of palm oil products that contribute US$ 7.5 billion in export revenues. Like any
other agro-based industries, it generates waste that could be utilized as a source of organic nutrients for microalgae culture.
Present investigation delves upon Isochrysis sp. culture in POME modified medium and its utilization as a supplement to Nanochloropsis sp. in rotifer cultures. The culture conditions were optimized using a 1 L photobioreactor (Temp: 23°C, illumination: 180 ∼ 200 μmol
photons m−2s−1, n = 6) and scaled up to 10 L outdoor system (Temp: 26–29°C, illumination: 50 ∼ 180 μmol photons m−2s−1, n = 3). Algal growth rate in photobioreactor (μ = 0.0363 h−1) was 55% higher compared to outdoor culture (μ = 0.0163 h−1), but biomass production was 1.3 times higher in outdoor culture (Outdoor = 91.7 mg m−2d−1; Photobioreactor = 69 mg m−2d−1). Outdoor culture produced 18% higher lipid; while total fatty acids (FA) was not significantly affected by the change in
culture systems as both cultures yield almost similar concentrations of fatty acids per gram of sample (photobioreactor = 119.17 mg
g−1; outdoor culture = 104.50 mg g−1); however, outdoor cultured Isochrysis sp. had 26% more polyunsaturated fatty acids (PUFAs). Rotifers cultured in Isochrysis sp./ Nanochloropsis sp. (1:1, v/v) mixture gave similar growth rate as 100% Nanochoropsis sp. culture (μ = 0.40 d−1), but had 45% higher counts of rotifers with eggs (t = 7, maximum). The Isochrysis sp. culture successfully lowered the nitrate (46%) and orthophosphate (83%) during outdoor culture. 相似文献
12.
The growth rate, reproductive aspects, and natural mortality of chimaeras and ratfish are poorly known. In this study, life-history
parameters for cockfish Callorhinchus callorhynchus (Holocephali—Callorhinchidae) are estimated, which is an important fish resource exploited in Chile. Specimens were sampled
from the artisanal fishery captures, from November 2006 to November 2007. The standard length (SL) of males fluctuated between
20 and 62 cm, and between 21 and 70 cm for females. Von Bertalanffy growth parameters were estimated through length-frequency
data analysis using MULTIFAN. The length-weight relationship and von Bertalanffy growth parameters were significantly different
for males and females, as well as the length at 50% maturity. For males a model with 5 age-classes was the best, with asymptotic
length L
∞ = 52 cm SL, growth coefficient K = 0.473 yr−1, and age at length zero t
0 = −0.690 yrs. For females the best model was represented by 10 age-classes (L
∞ = 70.3 cm SL, K = 0.193 yr−1, t
0 = −1.158 yrs) in the length-frequency data sets. Length at 50% maturity of males was estimated in 43.7 cm SL, and in 50.2 cm
SL for females. The natural mortality rate fluctuated between 0.42 and 0.82 yr−1 for males and between 0.12 and 0.37 yr−1 for females, depending upon the method used. It is concluded that C. callorhynchus is a species with life-history parameters significantly different between males and females, and such differences should
be taken into account in future population dynamics analysis. 相似文献
13.
Eme J Crossley DA Hicks JW 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(3):391-401
All embryonic and fetal amniotes possess a ductus(i) arteriosus(i) that allows blood to bypass the pulmonary circulation and
the non-functional lungs. The central hemodynamic of embryonic reptiles are unique, given the additional systemic aorta that
allows pulmonary circulatory bypass, the left aorta (LAo). The LAo exits in the right ventricle or ‘pulmonary side’ of reptilian
hearts in both embryos and adults, but its functional significance in ovo is unknown. This study investigated the role of
the LAo in embryonic American alligators by surgically occluding the LAo and measuring oxygen consumption and, in addition,
measured hemodynamic responses to hypoxia in embryonic alligators. We measured systemic cardiac output and primary chorioallantoic
membrane (CAM) artery blood flow for normoxic and hypoxic-incubated (10% O2) American alligator embryos (Alligator mississippiensis). Chronic blood flow (1–124 h) in the primary CAM artery for hypoxic-incubated embryos (92 ± 26 ml min−1 kg−1) was elevated when compared with normoxic-incubated embryos (29 ± 14 ml min−1 kg−1, N = 6; P = 0.039). For hypoxic-incubated embryos, acute LAo blood flow (49.6 ± 24.4 ml min−1 kg−1) was equivalent to the combined flow of the three systemic great vessels that arise from the left ventricle, the right aorta,
common carotid and subclavian arteries (43.6 ± 21.5 ml min−1 kg−1, N = 5). Similarly, for normoxic-incubated embryos, LAo blood flow (27.3 ± 6.6 ml min−1 kg−1) did not statistically differ from the other three vessels (18.4 ± 4.9 ml min−1 kg−1, N = 5). This study contains the first direct test of LAo function and the first measurements of blood flow in an embryonic
reptile. These data support the hypotheses that embryonic alligators utilize the LAo to divert a significant amount of right
ventricular blood into the systemic circulation, and that CAM blood flow increases following chronic hypoxic conditions. However,
surgical occlusion of the LAo did not affect egg
[(V)\dot]\textO2, \dot{V}_{{\text{O}}_{2}}, supporting the hypothesis that the LAo of reptiles is not critical to maintain in ovo oxygen consumption. 相似文献
14.
Daria Ezgeta-Balić Melita Peharda Christopher A. Richardson Marina Kuzmanić Nedo Vrgoč Igor Isajlović 《Helgoland Marine Research》2011,65(4):457-465
The age, growth, and population structure of the smooth clam Callista chione were determined from samples collected by hydraulic dredge and SCUBA at four locations in the eastern Adriatic during 2007
and 2008. The age of 436 clam shells was determined from internal growth lines present in shell sections, and the timing of
growth line formation was ascertained from monthly collections of clams to occur between August and September when sea water
temperatures were maximal. In addition, age of 30 older individuals was verified with acetate peels of polished and etched
shell sections. Differences were apparent in the age structure and growth rates of clams collected from the four locations
studied. Von Bertalanffy growth (VBG) curves obtained for clams from these locations were L
t
= 72.4 (1−e−0.25(t − 2.68)) (Rab Island), L
t
= 74.5 (1−e−0.15(t + 0.57)) (Pag Bay), L
t
= 79.3 (1−e−0.34(t − 0.97)) (Cetina estuary), and L
t
= 82.5 (1−e−0.11(t + 2.88)) (Kaštela Bay). The age of the clams ranged between 3 and 44 years; median clam ages were similar at three of the four locations
(14, 12, and 12 years, respectively), but was significantly lower in the Cetina estuary (4 years). The VBG growth constants
recorded from clams were within the range of values obtained for this species by previous authors. The observed local differences
in population structure indicate different levels of exploitation and illustrate the need to establish long-term strategies
for a sustainable exploitation of smooth clams in the Croatian Adriatic. 相似文献
15.
Guenterberg KD Lesinski GB Mundy-Bosse BL Karpa VI Jaime-Ramirez AC Wei L Carson WE 《Cancer immunology, immunotherapy : CII》2011,60(9):1281-1288
Interferon-alpha (IFN-α) is an immunomodulatory cytokine that is used clinically for the treatment of melanoma in the adjuvant
setting. The cellular actions of IFN-α are regulated by the suppressors of cytokine signaling (SOCS) family of proteins. We
hypothesized that the anti-tumor activity of exogenous IFN-α would be enhanced in SOCS1-deficient mice. SOCS1-deficient (SOCS1−/−) or control (SOCS1+/+) mice on an IFN-γ−/− C57BL/6 background bearing intraperitoneal (i.p.) JB/MS murine melanoma cells were treated for 30 days with i.p. injections
of IFN-A/D or PBS (vehicle). Log-rank Kaplan-Meier survival curves were used to evaluate survival. Tumor-bearing control SOCS1+/+ mice receiving IFN-A/D had significantly enhanced survival versus PBS–treated mice (P = 0.0048). The anti-tumor effects of IFN-A/D therapy were significantly enhanced in tumor-bearing SOCS1−/− mice; 75% of these mice survived tumor challenge, whereas PBS-treated SOCS1−/− mice all died at 13-16 days (P = 0.00038). Antibody (Ab) depletion of CD8+ T cells abrogated the anti-tumor effects of IFN-A/D in SOCS1−/− mice as compared with mice receiving a control antibody (P = 0.0021). CD4+ T-cell depletion from SOCS1−/− mice also inhibited the effects of IFN-A/D (P = 0.0003). IFN-A/D did not alter expression of CD80 or CD86 on splenocytes of SOCS1+/+ or SOCS1−/− mice, or the proportion of T regulatory cells or myeloid-derived suppressor cells in SOCS1+/+ or SOCS1−/− mice. An analysis of T-cell function did reveal increased proliferation of SOCS1-deficient splenocytes at baseline and in
response to mitogenic stimuli. These data suggest that modulation of SOCS1 function in T-cell subsets could enhance the anti-tumor
effects of IFN-α in the setting of melanoma. 相似文献
16.
Wang Xi-Ling Zhou Jin-Xing Yu Mao-De Li Zhen-Gang Jin Xiao-Yun Li Qi-You 《In vitro cellular & developmental biology. Plant》2011,47(3):434-440
Efficient plant regeneration is essential for successful transformation and in vitro polyploidy induction in mulberry. A high frequency (80%) of plant regeneration from hypocotyls occurred under in vitro conditions in mulberry (Morus multicaulis Poir.). We identified three key factors for enhancing successful regeneration based on earlier work: (1) hypocotyl position,
(2) the combination and concentration of growth regulators, and (3) the addition of AgNO3. The highest frequency of shoot regeneration was achieved using hypocotyl segments, which are proximal to apical meristems,
and the optimal culture conditions were Murashige and Skoog’s (MS) (Murashige and Skoog, 1962) basal medium supplemented with 3.0 mg l−1 6-benzylamino purine, 0.3 mg l−1 indole-3-acetic acid, 0.1% polyvinypyrrolidone, and 1.0 mg/l silver nitrate (AgNO3) under subdued light at 25 ± 2°C. Treating the shoots with 0.2% colchicine (dipping for 72 h) resulted in a 14% tetraploid
frequency, whereas a 20% tetraploid frequency resulted from using a 0.25% colchicine (dripping for 5 d) treatment, as determined
by chromosome number counts. The diploid plant chromosome number was 28 (2n = 2x = 28) and that of tetraploid plants was 56 (2n = 4x = 56). Regenerated shoots rooted easily in 8–10 d using half-strength basal MS medium with 0.5 mg l−1 indole-3-butyric acid and were successfully established in the soil. 相似文献
17.
Zhiyong Sun Juliana A. Ramsay Martin Guay Bruce A. Ramsay 《Applied microbiology and biotechnology》2009,82(4):657-662
Unsaturated medium-chain-length polyhydroxyalkanoates (MCL-PHA) were produced at a productivity of 0.63–1.09 g PHA l−1 h−1 with final PHA content ranging from 42.6 to 55.8% in single-stage, carbon-limited, fed-batch fermentations of Pseudomonas putida KT2440. A mixture of nonanoic acid (NA) and 10-undecenoic acid (UDA=) was fed exponentially to control growth rate. Varying the specific growth rate (0.14 h−1 vs. 0.23 h−1) at similar substrate feed ratios (NA:UDA= = 5:1) had little effect on the final PHA content and relative composition. However, decreasing the NA:UDA= ratio decreased the final amount of PHA produced from 56% with NA:UDA= = 5.07:1 to only 42% at NA:UDA= = 2.47:1. The molar fraction of all 3-hydroxyalkanoate monomers in the PHA product was relatively constant throughout each
fermentation, indicating that the final product was homogeneous rather than a mixture of different copolymers. A linear relationship
between unsaturation of the PHA produced and unsaturation of the carbon feed was found, which demonstrates the feasibility
of producing unsaturated MCL-PHAs with controlled polymeric composition in a fed-batch process. 相似文献
18.
Recent studies have identified common variants in or near GC, CYP2R1 and NADSYN1/DHCR7 to be associated with 25-hydroxyvitamin D [25(OH)D] levels in European populations. We aimed to examine whether these variants
also influence 25(OH)D levels in Chinese. Seven common variants were successfully genotyped and tested for associations with
plasma 25(OH)D levels in a population-based cohort of 3,210 Chinese Hans from Beijing and Shanghai. Six common variants at
GC (rs4588, rs7041, rs2282679 and rs1155563) and NADSYN1/DHCR7 (rs3829251 and rs1790349) loci were all significantly associated with lower plasma 25(OH)D levels (−0.036 ≤ β ≤ −0.076 per risk-allele, P ≤ 5.7 × 10−5), while CYP2R1-rs2060793 showed a trend toward association with 25(OH)D levels in the Shanghai subpopulation (P = 0.08), but not in the Beijing subpopulation (P = 0.82). Haplotype-based association analyses of the four GC variants showed that only the haplotype that contained all risk-alleles (TACC) was significantly associated with lower plasma
25(OH)D levels (β = −0.085, P = 2.3 × 10−9), while the haplotype containing the risk-alleles of rs4588 and rs2282679 (TATC) was marginally associated with lower 25(OH)D
levels (β = −0.054, P = 0.0562) when compared with GCTA haplotype carrying the four protective alleles. Most notably, conditional analyses showed
that only GC-rs4588 and GC-rs2282679 (r
2 = 0.97) remained significantly associated with 25(OH)D concentrations (P ≤ 1.9 × 10−5) after adjusting for the other two SNPs in GC. In conclusion, GC and NADSYN1/DHCR7 loci individually and collectively contribute to variation in plasma vitamin D levels in Chinese Hans. 相似文献
19.
By simultaneously analyzing the chlorophyll a fluorescence transient and light absorbance at 820 nm as well as chlorophyll fluorescence quenching, we investigated the
effects of different photon flux densities (0, 15, 200 μmol m−2 s−1) with or without 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the repair process of cucumber (Cucumis sativus L.) leaves after treatment with low temperature (6°C) combined with moderate photon flux density (200 μmol m−2 s−1) for 6 h. Both the maximal photochemical efficiency of Photosystem II (PSII) (F
v/F
m) and the content of active P700 (ΔI/I
o) significantly decreased after chilling treatment under 200 μmol m−2 s−1 light. After the leaves were transferred to 25°C, F
v/F
m recovered quickly under both 200 and 15 μmol m−2 s−1 light. ΔI/I
o recovered quickly under 15 μmol m−2 s−1 light, but the recovery rate of ΔI/I
o was slower than that of F
v/F
m. The cyclic electron transport was inhibited by chilling-light treatment obviously. The recovery of ΔI/I
o was severely suppressed by 200 μmol m−2 s−1 light, whereas a pretreatment with DCMU effectively relieved this suppression. The cyclic electron transport around PSI recovered
in a similar way as the active P700 content did, and the recovery of them was both accelerated by pretreatment with DCMU.
The results indicate that limiting electron transport from PSII to PSI protected PSI from further photoinhibition, accelerating
the recovery of PSI. Under a given photon flux density, faster recovery of PSII compared to PSI was detrimental to the recovery
of PSI or even to the whole photosystem. 相似文献
20.