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1.
Troy J. Cross Justin J. Kavanagh Toni Breskovic Petra Zubin Maslov Mihajlo Lojpur Bruce D. Johnson Zeljko Dujic 《PloS one》2013,8(6)
The effects of involuntary respiratory contractions on the cerebral blood flow response to maximal apnoea is presently unclear. We hypothesised that while respiratory contractions may augment left ventricular stroke volume, cardiac output and ultimately cerebral blood flow during the struggle phase, these contractions would simultaneously cause marked ‘respiratory’ variability in blood flow to the brain. Respiratory, cardiovascular and cerebrovascular parameters were measured in ten trained, male apnoea divers during maximal ‘dry’ breath holding. Intrathoracic pressure was estimated via oesophageal pressure. Left ventricular stroke volume, cardiac output and mean arterial pressure were monitored using finger photoplethysmography, and cerebral blood flow velocity was obtained using transcranial ultrasound. The increasingly negative inspiratory intrathoracic pressure swings of the struggle phase significantly influenced the rise in left ventricular stroke volume (R
2 = 0.63, P<0.05), thereby contributing to the increase in cerebral blood flow velocity throughout this phase of apnoea. However, these contractions also caused marked respiratory variability in left ventricular stroke volume, cardiac output, mean arterial pressure and cerebral blood flow velocity during the struggle phase (R
2 = 0.99, P<0.05). Interestingly, the magnitude of respiratory variability in cerebral blood flow velocity was inversely correlated with struggle phase duration (R
2 = 0.71, P<0.05). This study confirms the hypothesis that, on the one hand, involuntary respiratory contractions facilitate cerebral haemodynamics during the struggle phase while, on the other, these contractions produce marked respiratory variability in blood flow to the brain. In addition, our findings indicate that such variability in cerebral blood flow negatively impacts on struggle phase duration, and thus impairs breath holding performance. 相似文献
2.
Pawel J. Winklewski Yurii Tkachenko Kamila Mazur Jacek Kot Marcin Gruszecki Wojciech Guminski Krzysztof Czuszynski Jerzy Wtorek Andrzej F. Frydrychowski 《PloS one》2015,10(8)
Introduction
Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects.Methods
The pial artery and subarachnoid width response to handgrip (HGT) and cold test (CT) were studied in 20 healthy subjects. The cc-TQ and sas-TQ were measured using NIR-T/BSS; cerebral blood flow velocity (CBFV) was measured using Doppler ultrasound of the left internal carotid artery; heart rate (HR) and beat-to-beat mean BP were recorded using a continuous finger-pulse photoplethysmography; respiratory rate (RR), minute ventilation (MV), end-tidal CO2 (EtCO2) and end-tidal O2 (EtO2) were measured using a metabolic and spirometry module of the medical monitoring system. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations.Results
HGT evoked an increase in BP (+15.9%; P<0.001), HR (14.7; P<0.001), SaO2 (+0.5; P<0.001) EtO2 (+2.1; P<0.05) RR (+9.2%; P = 0.05) and MV (+15.5%; P<0.001), while sas-TQ was diminished (-8.12%; P<0.001), and a clear trend toward cc-TQ decline was observed (-11.0%; NS). CBFV (+2.9%; NS) and EtCO2 (-0.7; NS) did not change during HGT. CT evoked an increase in BP (+7.4%; P<0.001), sas-TQ (+3.5%; P<0.05) and SaO2(+0.3%; P<0.05). HR (+2.3%; NS), CBFV (+2.0%; NS), EtO2 (-0.7%; NS) and EtCO2 (+0.9%; NS) remained unchanged. A trend toward decreased cc-TQ was observed (-5.1%; NS). The sas-TQ response was biphasic with elevation during the first 40 seconds (+8.8% vs. baseline; P<0.001) and subsequent decline (+4.1% vs. baseline; P<0.05). No change with respect to wavelet coherence and wavelet phase coherence was found between the BP and cc-TQ oscillations.Conclusions
Short sympathetic activation does not affect the cardiac and respiratory contribution to the relationship between BP—cc-TQ oscillations. HGT and CT display divergent effects on the width of the subarachnoid space, an indirect marker of changes in intracranial pressure. 相似文献3.
目的:探讨CystatinC对大鼠蛛网膜下腔出血后自噬的影响.方法:成年雄性SD大鼠48只,随机分为假手术组(n=8)、SAH组(n=8)、安慰剂组(n=8)、Cystatin C组(分为低浓度(2μg/ml)、中浓度(5μg/ml)、高浓度(10 μg/ml),每个亚组(n=8)).采用视交叉池注血技术建立大鼠蛛网膜下腔出血模型.各组于建模后48 h后取颞底脑皮层,分别用western blot技术和免疫组化技术测定脑皮层组织中自噬标志物LC3和Beclin-1的变化,透射电镜观察脑皮层组织中自噬体和自噬溶酶体.结果:与假手术组相比,SAH组、安慰剂组大鼠脑皮层组织中自噬标志物Beclin-1及LC3于蛛网膜下腔出血后48 h后明显升高;与SAH组、安慰剂组相比,Cystatin C干预后大鼠脑皮层中Beclin-1及LC3表达水平进一步升高,且与浓度呈正相关,透射电镜下并可见Cystatin C组大鼠脑皮层组织中自噬体和自噬溶酶体数量增加.结论:Cystatin C可以进一步诱导激活大鼠蛛网膜下腔出血后脑组织的自噬,可能对蛛网膜下腔出血后的早期脑损伤起保护作用. 相似文献
4.
Maria Chiara Barsotti Paola Losi Enrica Briganti Elena Sanguinetti Angela Magera Tamer Al Kayal Roberto Feriani Rossella Di Stefano Giorgio Soldani 《PloS one》2013,8(12)
Background
Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization).Methodology/Principal Findings
Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2) and inflammatory response evaluation (NFκB). Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v). Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (p<0.05 vs. control), comparably to the positive control. Both platelet lysate concentrations activated important inflammatory pathways such as ERK1/2 and NFκB with the same early kinetics, whereas the effect was different for later time-points.Conclusion/Significance
These data suggest the possibility of using allogeneic platelet lysate as both an alternative to growth factors commonly used for cell culture and as a tool for clinical regenerative application for wound healing. 相似文献5.
刘根平 《基因组学与应用生物学》2020,39(1):314-319
为了考察食品级槲皮素粉对机体最大摄氧量和耐力的影响,本研究纳入20名健康的大学生志愿者作为本研究的研究对象。将受试者随机分为A组和B组,每组10名,A组饮用剂量为1 mg/mL的槲皮素饮料,B组饮用安慰剂饮料,每天饮用1 000 m L。饮用7 d后,通过自行车分级运动测试最大摄氧量(VO2max),通过骑行疲劳时间测试耐力,同时检测血清丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)含量。然后进行交叉实验并测试VO2max、骑行疲劳时间及抗氧化指标。研究显示,与基线VO2max相比,饮用槲皮素饮料后VO2max显著升高13.21%,而饮用安慰剂饮料后的VO2max与基线无显著差异。与基线骑行疲劳时间相比,饮用槲皮素饮料后骑行疲劳时间显著升高25.15%,而饮用安慰剂饮料后的骑行疲劳时间与基线无显著差异。与基线血清MDA相比,饮用安慰剂饮料后受试者血清MDA显著升高27.15%,而饮用槲皮素饮料可抑制血清MDA的升高。与基线血清SOD和GSH-Px相比,饮用安慰剂饮料后受试者血清SOD和GSH-Px分别降低了20.49%和21.08%,而饮用槲皮素饮料可抑制血清SOD和GSH-Px的降低,表明槲皮素可显著提高骑行运动过程中受试者的VO2max和耐力。本研究初步表明,补充槲皮素可通过降低运动过程中MDA水平来减少脂质过氧化损伤。另外,槲皮素通过抑制运动过程中SOD和GSH-Px的降低来提高机体的抗氧化能力,从而延缓疲劳。 相似文献
6.
目的:血管回声跟踪(echo-tracking,ET)技术探讨长期吸烟及戒烟对颈总动脉(common carotid artery,CCA)及肱动脉(brachial artery,BA)弹性的影响.方法:受试者为吸烟组(80例,男性,46±岁)和正常对照组(25例,男性,45±6岁),戒烟组在戒烟六个月后,根据戒烟情况将受试者分为成功戒烟组(23人)、部分戒烟组(25人)、戒烟失败组(32人),应用ET技术检测各吸烟组戒烟前及戒烟六个月后CCA及BA弹性(僵硬度β、弹性模量Ep、脉搏波传导速度PWVβ)的变化,同时检测每日吸烟量、吸烟指数、血脂、血糖、血压等各项指标,并与正常对照组比较.结果:(1)正常对照组与各吸烟组戒烟前及戒烟后血脂、血糖、血压、体重指数等指标比较均无统计学差异(P>0.05).(2)各吸烟组戒烟前每日吸烟量、吸烟指数等指标比较均无统计学差异(P>0.05).(3)各吸烟组戒烟前CCA及BA的β、Ep、PWVβ较正常对照组均明显增高,具有显著统计学差异(P<0.001).(4)各吸烟组戒烟后,成功戒烟组CCA及BA的β、Ep、PWVβ与正常对照组无统计学差异(P>0.05),成功戒烟组CCA及BA的β、Ep、PWVβ较戒烟失败组减低,具有统计学差异(P<0.05,P<0.01),部分戒烟组CCA及BA的β、Ep、PWVβ与正常对照组有统计学差异(P<0.05).结论:吸烟引起CCA及BA弹性减低,成功戒烟可使CCA及BA弹性改善,BA改善效果更明显. 相似文献
7.
This study investigates the influence of gap width and turf type on the growth of planted seedlings of the Australian forb Bulbine bulbosa (bulbine lily) and subsequent recruitment of this species from self-sown seed. In a low-productivity turf of Danthonia setacea (bristly wallaby grass), planted Bulbine seedlings established satisfactorily in all gaps 50 mm wide or larger. In highly productive turfs of Festuca arundinacea (tall fescue) successful, establishment and growth of planted seedlings required a competition-free gap more than 200 mm wide. Successful recruitment of self-sown Bulbine seedlings was observed in all gap widths in Danthonia turfs. In Festuca, however, seedling recruitment was low, irrespective of gap width. The results are related to establishing Bulbine bulbosa in habitat reconstruction programs in southeastern Australia. 相似文献
8.
目的:观察PerClot^TM多聚糖止血颗粒在兔股动脉局部止血效果。方法:分离并剪断兔股动脉,应用多聚糖止血颗粒止血,通过测定出血量与止血时间同阴性对照组对比了解活动患肢对止血稳定性的影响。结果:受试2组平均出血量如下:PerClot^TM组:(1.46±0.06)g;阴性对照组(2.48>±0.10)g。统计分析后可知PerClot^TM组较阴性对照组出血量减少(P〈0.叭。平均止血时间如下:PerClot^TM组:(100±30.1)s;阴性对照组(200±36.33)g。统计分析后可知PerClot^TM组较阴性对照组止血时间减少(P〈0.01).活动患肢对止血稳定性无影响。结论:多聚糖颗粒止血效果可靠,有临床应用前景,值得进行临床实验。 相似文献
9.
目的通过高脂喂养兔制造动脉粥样硬化动物模型,研究G-CSF对不同动脉段内皮形态和功能变化的影响及相互关系。方法30只新西兰成年雄兔随机分4组,分为对照组6只,高脂喂养组、普通及高脂喂养+G-CSF组各8只,分别测定血脂及血清NO浓度,各取胸主动脉、颈总动脉、股动脉,采用病理分析及扫描电镜观察内皮形态的不同变化,同时用RT-PCR方法测定eNOS、ET-1基因的表达了解不同动脉段的内皮功能变化。结果高脂喂养后兔血脂、NO浓度明显升高,病理发现动脉内膜增厚,以大动脉最著,小动脉最次,扫描电镜下内皮细胞的凋亡、变形亦然。ET-1基因表达相对定量次序为胸主动脉〉颈总动脉〉股动脉,eNOS基因反之。应用G-CSF后大动脉内皮功能及形态受到明显影响,但小型动脉变化不大。结论高脂喂养兔能成功制造动脉粥样硬化模型,成模后动脉内皮功能显著受损,其中以大型动脉显著,同时内皮形态出现相应变化。应用G-CSF对全身动脉系统有影响,且动脉越小,影响越小,说明粥样硬化动脉内皮形态与功能改变之间存在必然联系,对G-CSF的反应也不同。 相似文献
10.
Daniela Pinter James Sumowski John DeLuca Franz Fazekas Alexander Pichler Michael Khalil Christian Langkammer Siegrid Fuchs Christian Enzinger 《PloS one》2014,9(1)
Background
Previous work suggested greater intellectual enrichment might moderate the negative impact of brain atrophy on cognition. This awaits confirmation in independent cohorts including investigation of the role of T2-lesion load (T2-LL), which is another important determinant of cognition in MS. We here thus aimed to test this cognitive reserve hypothesis by investigating whether educational attainment (EA) moderates the negative effects of both brain atrophy and T2-LL on cognitive function in a large sample of MS patients.Methods
137 patients participated in the study. Cognition was assessed by the “Brief Repeatable Battery of Neuropsychological Tests.” T2-LL, normalized brain volume (global volume loss) and third ventricle width (regional volume loss) served as MRI markers.Results
Both T2-LL and atrophy predicted worse cognition, with a stronger effect of T2-LL. Higher EA (as assessed by years of education) also predicted better cognition. Interactions showed that the negative effects of T2-LL and regional brain atrophy were moderated by EA.Conclusions
In a cohort with different stages of MS, higher EA attenuated the negative effects of white matter lesion burden and third ventricle width (suggestive of thalamic atrophy) on cognitive performance. Actively enhancing cognitive reserve might thus be a means to reduce or prevent cognitive problems in MS in parallel to disease modifying drugs. 相似文献11.
J A Batista-da-Silva 《Neotropical Entomology》2014,43(1):48-52
Abiotic factors, such as lunar phases and tides, have a significant effect on insect development. Reproduction and immature development are usually interlinked to these abiotic factors. The tide is at its highest levels at full moon or new moon, hindering the feeding of the immature or causing their drowning. The oviposition by adult females is also compromised on these days because much of the available food is submerged. Another important abiotic factor is the wind, which displaces odoriferous particles in the air. Wind speed and direction are important elements to indicate potential sources of food for insects. I report on the effects of lunar phases, tides, and wind speed on the Calliphoridae fauna in mangrove swamps. The different species collected were identified, and the predominant species in the area were quantified. A total of 1,710 flies were collected over a 1-year period. Six Calliphoridae flies, Chloroprocta idioidea (Robineau-Desvoidy), Chrysomya megacephala (Fabricius), Chrysomya albiceps (Wiedemann), Chrysomya putoria (Wiedemann), Cochliomyia macellaria (Fabricius), and Lucilia eximia (Wiedemann) were collected. Data indicated that lunar phases have a significant effect on the abundance of C. albiceps (r?=?0.39, p?<?0.01), and that the variation of the tides also affected the abundance of C. putoria (r?=?0.40, p?<?0.00), C. macellaria (r?=?0.41, p?<?0.00), and C. idioidea (r?=?0.31, p?<?0.04). The wind speed, however, did not affect these species. 相似文献
12.
目的:观察灯延颗粒对结扎冠状动脉所致大鼠心肌缺血的影响。方法:采用结扎冠状动脉左前降支致心肌缺血模型,灯延颗粒0.35、0.70、1.40g/kg灌胃给药14天后,观察灯延颗粒的药理作用。结果:①灯延颗粒对心肌缺血大鼠的心脏功能有明显的改善作用,能增强心肌收缩力,改善心肌舒张的顺应性,表现为心率加快、颈动脉血压、左心室内收缩压、左心室压力微分±dp/dt明显增高,与模型组比较有明显差异(P<0.05或P<0.01);②模型组与假手术组比较血清中SOD、LDH、CK含量显著升高,MDA显著降低;灯延颗粒能明显减少血清中SOD、LDH、CK含量,明显增加血清中MDA含量,与模型组比较有显著差异(P<0.05或P<0.01);③模型组大鼠出现明显的心肌缺血和心肌梗死;灯延颗粒各组心肌缺血及心肌梗死程度与模型组比较,其病变程度显著减轻(P<0.01);④光镜观察可见灯延颗粒能明显减轻心肌病理损伤。结论:灯延颗粒对大鼠结扎冠状动脉所致心肌缺血损伤具有明显的保护作用。 相似文献
13.
Effect of Model Sorptive Phases on Phenanthrene Biodegradation: Molecular Analysis of Enrichments and Isolates Suggests Selection Based on Bioavailability 总被引:2,自引:6,他引:2
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M. Friedrich R. J. Grosser E. A. Kern W. P. Inskeep D. M. Ward 《Applied microbiology》2000,66(7):2703-2710
Reduced bioavailability of nonpolar contaminants due to sorption to natural organic matter is an important factor controlling biodegradation of pollutants in the environment. We established enrichment cultures in which solid organic phases were used to reduce phenanthrene bioavailability to different degrees (R. J. Grosser, M. Friedrich, D. M. Ward, and W. P. Inskeep, Appl. Environ. Microbiol. 66:2695–2702, 2000). Bacteria enriched and isolated from contaminated soils under these conditions were analyzed by denaturing gradient gel electrophoresis (DGGE) and sequencing of PCR-amplified 16S ribosomal DNA segments. Compared to DGGE patterns obtained with enrichment cultures containing sand or no sorptive solid phase, different DGGE patterns were obtained with enrichment cultures containing phenanthrene sorbed to beads of Amberlite IRC-50 (AMB), a weak cation-exchange resin, and especially Biobead SM7 (SM7), a polyacrylic resin that sorbed phenanthrene more strongly. SM7 enrichments selected for mycobacterial phenanthrene mineralizers, whereas AMB enrichments selected for a Burkholderia sp. that degrades phenanthrene. Identical mycobacterial and Burkholderia 16S rRNA sequence segments were found in SM7 and AMB enrichment cultures inoculated with contaminated soil from two geographically distant sites. Other closely related Burkholderia sp. populations, some of which utilized phenanthrene, were detected in sand and control enrichment cultures. Our results are consistent with the hypothesis that different phenanthrene-utilizing bacteria inhabiting the same soils may be adapted to different phenanthrene bioavailabilities. 相似文献
14.
Zhang Yong Xia Qin Jian Sun Hua Yang Ming Xia Zhang Ru Ban Ge Lin Xu Ya Ping Wu Le Xin Wang Yi Feng Du 《PloS one》2015,10(6)
Background and Objectives
Carotid artery stenting (CAS) is an important therapeutic strategy for patients with carotid artery stenosis. However, the potential influence of CAS on cognitive function in patients with carotid artery stenosis and cerebral lacunar infarction has not been determined. This study investigated changes in cognitive function associated with CAS and the factors related to these changes.Methods
This prospective cohort study comprised 579 Chinese patients with cerebral lacunar infarction and carotid artery stenosis for whom CAS was indicated, and a matched control group of 552 healthy individuals. Cognitive function before CAS and at scheduled intervals from 6 months to 3 years was assessed with instruments that included the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) scale. Potential factors that might affect cognitive function were analyzed via logistic regression.Results
The MMSE and MoCA scores of the patients before CAS were significantly lower than that of the control subjects. These scores were significantly higher 6 months after CAS and sustained or increased throughout the 3-year follow-up. Also significantly improved after CAS from baseline were scores for an alternating trail test, cube copying, clock-drawing, attention, and delayed recall in an auditory-verbal learning test. Logistic regression analyses showed that age greater than 65 y, little education, diabetes, and hypertension were independent risk factors for deteriorated MoCA scores 3 years after CAS.Conclusion
CAS was associated with significantly improved cognitive function in cerebral lacunar infarction patients with severe stenosis. 相似文献15.
The purpose of this study was to a) determine the heart rate variability (HRV) and saliva markers of immunity (salivary immunoglobulin A; sIgA) and stress (salivary alpha-amylase; sAA) responses to chronic training in elite swimmers with a disability; and b) identify the relationships between HRV, sIgA, sAA and training volume. Eight members of a high performance Paralympic swimming program were monitored for their weekly resting HRV, sIgA and sAA levels in the 14 weeks leading up to a major international competition. The 14 week training program included aerobic, anaerobic, power and speed, and taper training phases, while also incorporating two swimming step tests and two swimming competitions. Specific time (root mean square of the successive differences; RMSSD) and frequency (high frequency normalized units [HFnu]) domain measures, along with non-linear indices (standard deviation of instantaneous RR variability; SD1 and short term fractal scaling exponent; α1) of HRV were used for all analyses with effects examined using magnitude-based inferences. Relationships between HRV and saliva markers were identified by Spearman rank rho (ρ) correlation coefficients. Compared with week 1, SD1 was very likely lower (96/4/0, ES = -2.21), while sAA was very likely elevated (100/0/0, ES = 2.32) at the beginning of week 7 for all athletes. The training program did not alter HRV or saliva whereas competition did. There were also no apparent differences observed for HRV, sIgA and sAA between each of the training phases during the 14 week swimming program. Correlations were observed between sAA and SD1 (ρ = -0.212, p<0.05), along with sAA and mean HR (ρ = 0.309, p<0.05). These results show that high level national competition influences depresses HRV (SD1) and increases saliva biomarkers of stress (sAA). It appears that a well-managed and periodised swimming program can maintain these indices within normal baseline levels. The study also highlighted the parasympathetic nervous system influence on sAA. 相似文献
16.
Effect of Model Sorptive Phases on Phenanthrene Biodegradation: Different Enrichment Conditions Influence Bioavailability and Selection of Phenanthrene-Degrading Isolates 总被引:2,自引:3,他引:2
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Robert J. Grosser Michael Friedrich David M. Ward William P. Inskeep 《Applied microbiology》2000,66(7):2695-2702
The sorption of organic contaminants by natural organic matter (NOM) often limits substrate bioavailability and is an important factor affecting microbial degradation rates in soils and sediments. We hypothesized that reduced substrate bioavailability might influence which microbial assemblages are responsible for contaminant degradation under enrichment culture conditions. Our primary goal was to characterize enrichments in which different model organic solid phases were used to establish a range of phenanthrene bioavailabilities for soil microorganisms. Phenanthrene sorption coefficients (expressed as log KD values) ranged from 3.0 liters kg−1 for Amberlite carboxylic acid cation-exchange resin (AMB) to 3.5 liters kg−1 for Biobeads polyacrylic resin (SM7) and 4.2 liters kg−1 for Biobeads divinyl benzene resin (SM2). Enrichment cultures were established for control (no sorptive phase), sand, AMB, SM7, and SM2 treatments by using two contaminated soils (from Dover, Ohio, and Libby, Mont.) as the initial inocula. The effects of sorption by model phases on the degradation of phenanthrene were evaluated for numerous transfers in order to obtain stable microbial assemblages representative of sorptive and nonsorptive enrichment cultures and to eliminate the effects of the NOM present in the initial inoculum. Phenanthrene degradation rates were similar for each soil inoculum and ranged from 4 to 5 μmol day−1 for control and sand treatments to approximately 0.4 μmol day−1 in the presence of the SM7 sorptive phase. The rates of phenanthrene degradation in the highly sorptive SM2 enrichment culture were insignificant; consequently, stable microbial populations could not be obtained. Bacterial isolates obtained from serial dilutions of enrichment culture samples exhibited significant differences in rates of phenanthrene degradation performed in the presence of SM7, suggesting that enrichments performed in the presence of a sorptive phase selected for different microbial assemblages than control treatments containing solid phase phenanthrene. 相似文献
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Dhananjay Bhattacharyya Manju Bansal 《Journal of biomolecular structure & dynamics》2013,31(1):213-226
Abstract The groove widths of DNA helix, especially minor groove width, are generally believed to be important for recognition of DNA by various types of ligands. It has been postulated earlier that large negative propeller twist, in the AT rich regions compresses the minor groove of duplex DNA A systematic study has now been carried out by generating models with different values of local doublet and intra-basepair parameters and calculating their minor groove widths. It is found that several local doublet parameters affect the minor groove width but it depends most strongly on the local step parameters roll and slide when each parameter is considered individually. However, a detailed analysis of the various local parameters within the B-DNA family of crystal structures indicates that propeller twist and slide are most strongly correlated with the observed values of minor groove width. The groove depth is also strongly correlated with slide. Thus the local base sequence dependent variations in slide can modify both the groove width and depth and consequently determine the ligand binding properties of DNA. 相似文献
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野生稻优异基因分子标记定位与利用研究进展 总被引:2,自引:0,他引:2
对野生稻中抗(耐)生物胁迫和非生物胁迫等许多有用的遗传性状,抗病虫、耐非生物胁迫环境、高产和细胞质雄性不育恢复等优异基因的分子标记定位研究进行了综述,评价了野生稻中的这些优异基因的利用现状及其应用前景。 相似文献
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Tamás Cecília Szűcs Péter Rakszegi Mariann Tamás László Bedő Zoltán 《Plant Cell, Tissue and Organ Culture》2004,79(1):39-44
In this study, tissue culture method for plant regeneration from immature embryos of elite Hungarian winter wheat varieties was established. The influence of the growth regulators and the concentration of macroelements in the regeneration medium and of the incubation temperature and light intensity on regeneration frequency were investigated. The most noticeable effect on regeneration frequency was achieved by simultaneously reducing both the incubation temperature to 23 °C and the concentration of macroelements in the regeneration medium to half-strength. This modification increased the average regeneration frequency from about 10–78%. Changes in the light intensity and temperature gave an average plant regeneration frequency of 83%. 相似文献
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