Hg^(2+)对水鳖(Hydrocharis dubia)叶片生理生化及超微结构的毒害效应

研究了不同浓度Hg2 +对水鳖叶片光合放氧速率、呼吸速率、细胞膜透性、硝酸还原酶活性以及超微结构的毒害影响 .结果表明 ,随着Hg2 +浓度的增加 ,水鳖叶片的光合放氧速率逐渐下降 ,呼吸速率、硝酸还原酶活性先升后降 ,而细胞膜透性则逐渐上升 .电镜观察发现 ,水鳖叶细胞遭受Hg2 +毒害初期 ,染色质凝集 ,叶绿体中类囊体片层以及线粒体嵴突膨胀 .随着叶细胞遭受毒害程度的加深 ,核膜破裂 ,染色质与核质消失 ,叶绿体膨胀解体 。

双齿许水蚤(Pseudodiaptomus dubia)对亚热带虾池Cu和Zn的富集

重金属污染是对虾养殖环境主要污染现象之一,查明重金属在环境中的迁移规律对养殖水质调控和对虾健康养殖具有重要意义。本文采用火焰原子吸收分光光度计测定在不同暴露时间下双齿许水蚤（Pseudodiaptomus dubia）对Cu和Zn的富集量,研究了双齿许水蚤对Cu和Zn富集动力学,并探讨了温度和盐度对其富集的影响。结果表明：双齿许水蚤对Cu和Zn的富集过程均经历了快速、慢速和平衡3个阶段,实验24 h达到富集平衡,双齿许水蚤对Cu和Zn的富集动力学参数k1（Cu）=0.077〈k1（Zn）=0.272,BCF（Cu）=0.344〈BCF（Zn）=2.252,双齿许水蚤对Zn的富集速率和富集能力均大于Cu。温度对双齿许水蚤Cu和Zn富集的影响显著（p〈0.05）,最适温度范围为15～30℃,盐度对双齿许水蚤Zn富集的影响极显著（p〈0.01）,而对Cu富集的影响不显著（p〉0.05）,对Cu和Zn适宜的富集盐度范围为10～35。这些研究结果说明,双齿许水蚤对Cu和Zn均具有较强的富集能力,在对虾养殖期间,应通过循环过滤设施去除受到重金属污染池塘中的浮游动物,减少幼虾对其摄食和虾体中重金属的积累量,从而降低食品安全隐患。

Lanthanum Relieved Toxic Effects Caused by Nickel in Hydrocharis dubia B L. Backer Leaves

The paper briefly dealt with relieving toxic effects of La on high aquatic plant-Hydrocharis dubia B L. Backer growing in the solution containing different concentration of Ni. The results show that La can relieve the reduction of chlorophyll content, the accumulation of MDA(malondiadehyde) and the elevation of relative membrane penetrability (RMP). After adding 10 mg . L-1 La to the solution, the activities of SOD and CAT in the leaves of Hydrocharis dubia B L. Backer increases compared with those of the single treatment of Ni, while the activity of POD decreases. It reveals that la enhances the abilities of scavenging the activated oxygen in the plant and alleviates the damage to the membranes. The soluble protein content with Ni and La compound treatment is higher than that of single Ni does, and proline content is contrary to the soluble protein content. So La improves the resistance of Hydrocharis dubia B. L. Backer to the stress of Ni. However, La can aggravate the damage to the cells under the extremely high concentration of Ni treatment.

Standardization of DNA Extraction Method from Mature Dried Leaves and ISSR-PCR Conditions for Melia dubia Cav. —A Fast Growing Multipurpose Tree Species

Melia dubia Cav. of family Meliaceae is a fast growing, high value tree species native to India. Isolating DNA from matured dried leaves of M. dubia was difficult due to accumulation of secondary metabolites, majorly polyphenolics, which resulted in dark brown to black colour of the pellet. In this study, a modified STE-(Sucrose, Tris-HCl and Ethylene Diamine Tetra Acetic Acid) CTAB (hexadecyltrimethylammonium bromide) method was standardized for removal of polyphenolics. The protocol developed yielded 200 - 1000 ng/μl of quality DNA without any impurities as evident by A260/280 ratio ranging from 1.75 - 2.0. It was also suitable for extracting quality DNA from other members of Meliaceae like Azadirachta indica and Melia azedarach. In downstream applications, the extracted DNA was used for PCR amplification by using ISSR and SSR markers. ISSR PCR conditions were optimized in a reaction volume of 25 μl, consisting of 30 ng of template DNA, 1.5 mM MgCl2, 200 μM of each of dNTPs and 2 U of Taq polymerase. The best amplification was observed and the same was applicable for SSR markers.

Effect of diet on the development, survival, and reproduction of the calanoid copepod Pseudodiaptomus dubia

Pseudodiaptomus dubia is a calanoid copepod abundant in the mariculture ponds of southern China. However, our understanding of the population dynamics of P . dubia in aquaculture ponds is limited. In this study, groups of larval P . dubia were each fed a diff erent microalgal species, and the eff ects of these diff erent diets on development, survival, and reproduction were assessed. The fi ve microalgae used were species common in aquaculture farms in China, and included two chlorophytes ( Chlorella saccharophila and Platymonas subcordiformis ), one golden microalga ( Isochrysis zhanjiangensis ), and two diatoms ( Chaetoceros muelleri and Cyclotella meneghiniana ). Our results indicated that C . saccharophila was not a suitable food for larval P . dubia , as all larvae fed this microalga died at stage III (as copepodites). The survival rates of P . dubia larvae fed C . muelleri , I . zhanjiangensis , and P . subcordiformis were signifi cantly higher than that of larvae fed C . meneghiniana . In the adult stage, copepods fed C . muelleri , I . zhanjiangensis , and C . meneghiniana produced more nauplii (430-566 nauplii/female), had higher intrinsic growth rates (0.2- 0.253/d), and better longevity (59-60 days) than those fed P . subcordiformis . Our results therefore suggest that P . dubia has diff erent nutritional needs and food preferences at diff erent life stages. For example, P . subcordiformis was suitable for developing larvae but not for breeding adults, while C . meneghiniana was suitable for breeding adults but not for developing larvae. Both C . muelleri and I . zhanjiangensis were excellent foods for P . dubia throughout the entire life cycle.

Antibacterial activity of Myrciaria dubia(Camu camu) against Streptococcus mutans and Streptococcus sanguinis

Objective:To evaluate the antibacterial and cytotoxic effect of Myrciaria dubia(Camu camu)(M.dubia) methanol extract,against Streptococcus mutans(ATCC 25175)(S.mutans) and Streptococcus sanguinis(ATCC 10556)(S.sanguinis).Methods:Two methanol extracts of M.dubia were prepared in vitro,from the seeds and pulp.Ten independent tests were prepared for each type of extract,using 0.12% chlorhexidine solution as positive control.Agar diffusion test was used by preparing wells with the experimental solutions cultivated in anaerobic conditions for 48 h at 37C.Meanwhile,the minimum inhibitory concentration and the cytotoxic effect over MDCK cell line was found.Results:A higher antibacterial effect was observed with the methanol seed extract with an inhibitory halo of(21.36 ± 6.35) mm and(19.21 ± 5.18) mm against S.mutans and S.sanguinis,respectively.The methanol extract of the pulp had an effect of(16.20 ± 2.08)mm and(19.34 ± 2.90) mm,respectively.The minimum inhibitory concentration of the pulp extract was 62.5 mg/mL for both strains,whereas for the seed antibacterial activity was observed even at low concentrations.The CC50 of the seeds extract was at a higher concentration than 800 mg/mL and 524.37 mg/mL for the pulp extract.Conclusions:The experimental findings demonstrated the antibacterial effect of the methanol extract of M.dubia against S.mutans and S.sanguinis.These extracts were not cytotoxic at high concentrations.

Provenance variations in proximate principles,mineral matter,total phenols and phytochemicals of Melia dubia drupes:an unexplored alternate livestock feed stock

This research was carried out on nine provenances from the north Western Ghats to quantify proximate principles,mineral matter,total phenols and other phytochemicals in Melia dubia drupe pulp.Drupe biometric,biomass attributes,proximate principles,mineral matter and total phenols diff ered signifi cantly among the provenances.The average drupe length and width was 26.5 and 22.3 mm,respectively.Average drupe and pulp fresh weight,pulp dry weight and stone weight were 783.1,552.1,165.1,and 179.8 g/100 drupes,respectively.Pulp,dry matter and moisture per cent were 70.5%,29.9%and 70.0%,respectively.Average crude fi bre,protein,ether extract,total ash and nitrogen-free extract were 8.3%,7.6%,5.1%,6.3%,and 72.6%,respectively.Average Ca,Mg,P and K levels were 0.5%,0.2%,0.2%,and 2.0%,respectively.Total phenols were 0.4%.Cluster analysis showed that the study area may be divided into three distinct provenances,each having diff erent drupe traits and proximate composition,including mineral components.Gas-chromatography mass-spectrometry analysis revealed 27 phytochemicals,many of which possess benefi cial biological attributes.The implications of this provenance variation study should be useful for future improvement in terms of better drupe pulp nutrition for livestock feed.Further study suggests that M.dubia pulp could be categorized as a good feed source with low fi bre,energy,fat and mineral levels.All proximate parameters,mineral matter content and total phenols are within prescribed limits.

镍添加对水鳖(Hydrocharis dubia)叶片镍和营养元素含量以及氧化胁迫和抗氧化系统的影响

采用营养液水培的方法,研究不同镍(Ni)添加浓度(0、0.05、0.10、0.15、0.20 mmol/L)对水鳖(Hydrocharis dubia)叶片中Ni元素积累、营养元素(Ca、Mg、K、Fe和Mn)含量、氧化胁迫和抗氧化系统的影响.结果显示:(1)叶片中Ni含量以浓度依赖的方式增加;(2)叶片中营养元素含量(Ca、Mg、K、Fe、Mn)也受影响,其中Ca、Mg含量随Ni浓度增加而显著上升;K含量随Ni浓度增加有所升高,但不显著;Mn含量虽在较大Ni浓度时有所下降,但处理组始终高于对照组;而Fe含量则随Ni浓度增加而下降;(3)Ni胁迫诱导了明显的氧化胁迫,主要表现为:O·-2产生速率以及过氧化氢和丙二醛含量显著升高,可溶性蛋白以及光合色素含量明显下降;(4)随着Ni浓度的升高,过氧化物酶活性逐渐升高,过氧化氢酶活性呈下降趋势,超氧化物歧化酶活性在Ni添加浓度为0.05 mmol/L时出现短暂升高随后下降;维生素E和黄酮含量随Ni浓度增加呈缓慢上升趋势;还原型谷胱甘肽未发生明显变化,非蛋白巯基和植物络合素含量均表现为先升后降的趋势;总抗氧化能力随Ni浓度升高先增强后减弱.由此可见,Ni添加引起水鳖叶片中Ni元素的累积和营养元素含量变化,同时产生明显的氧化胁迫,打破了抗氧化系统的平衡.

Artemdubinoids A-N:novel sesquiterpenoids with antihepatoma cytotoxicity from Artemisia dubia

In pursuit of effective agents for hepatocellular carcinoma derived from the Artemisia species,this study built upon initial findings that an ethanol(EtOH)extract and ethyl acetate(EtOAc)fraction of the aerial parts of Artemisia dubia Wall.ex Bess.exhibited cytotoxicity against HepG2 cells with inhibitory rates of 57.1%and 84.2%(100μg·mL−1),respectively.Guided by bioactivity,fourteen previously unidentified sesquiterpenes,artemdubinoids A–N(1–14),were isolated from the EtOAc fraction.Their structural elucidation was achieved through comprehensive spectroscopic analyses and corroborated by the comparison between the experimental and calculated ECD spectra.Single crystal X-ray diffraction provided definitive structure confirmation for artemdubinoids A,D,F,and H.Artemdubinoids A and B(1–2)represented unique sesquiterpenes featuring a 6/5-fused bicyclic carbon scaffold,and their putative biosynthetic pathways were discussed;artemdubinoid C(3)was a novel guaianolide derivative that might be formed by the[4+2]Diels–Alder reaction;artemdubinoids D and E(4–5)were rare 1,10-seco-guaianolides;artemdubinoids F–K(6–11)were chlorinecontaining guaianolides.Eleven compounds exhibited cytotoxicity against three human hepatoma cell lines(HepG2,Huh7,and SKHep-1)with half-maximal inhibitory concentration(IC50)values spanning 7.5−82.5μmol·L^(−1).Artemdubinoid M(13)exhibited the most active cytotoxicity with IC50 values of 14.5,7.5 and 8.9μmol·L^(−1)against the HepG2,Huh7,and SK-Hep-1 cell lines,respectively,which were equivalent to the positive control,sorafenib.

蒙药用植物赤瓟块根中过氧化物酶的稳定性分析

研究蒙药用植物赤瓟(Thladiantha dubia Bunge)块根过氧化物酶(POD)的活性,确定最适反应温度和pH,并测定其在不同温度条件、pH和保存条件下的稳定性。结果表明,赤瓟块根POD的最适温度为30℃,最适pH为7.2,在不同温度条件下保温30 min时,高于40℃时酶活性开始降低,保温60 min时,高于35℃时酶活性开始降低;该酶的pH稳定性范围为6.6~8.2;室温光照条件下存放1 d后活性开始下降,7 d时活性基本丧失,室温黑暗条件保存3 d后活性开始降低,8 d时活性完全丧失。赤瓟块根POD在30℃、中性条件和黑暗环境中具有较高的活性和稳定性。

Algae (Raphidocelis subcapitata) mitigate combined toxicity of microplastic and lead on Ceriodaphnia dubia

Microplastics(MPs)have been recognized as a new class of emerging contaminants in recent years.They not only directly impact aquatic organisms,but also indirectly impact these organisms by interacting with background toxins in the environment.Moreover,under realistic environmental conditions,algae,a natural food for aquatic organisms,may alter the toxicity pattern related to MPs.In this research,we first examined the toxicity of MPs alone,and their effect on the toxicity of lead(Pb)on Ceriodaphnia dubia(C.dubia),a model aquatic organism for toxicity survey.Then,we investigated the effect of algae on the combined toxicity of MPs and Pb.We observed that,MPs significantly increased Pb toxicity,which was related to the increase in soluble Pb concentration and the intake of Pb-loaded MPs,both of which increased the accumulation of Pb in C.dubia.The presence of algae mitigated the combined toxicity of MPs and Pb,although algae alone increased Pb accumulation.Therefore,the toxicity mitigation through algae uptake came from mechanisms other than Pb accumulation,which will need further investigation.

Understanding the role of nano-TiO2 on the toxicity of Pb on C.dubia through modeling-Is it additive or synergistic?

Nano-TiO_(2) can remarkably increase lead(Pb)toxicity in aquatic organisms.However,the mechanism of this toxicity,additive or synergistic,is not well understood.To explore this mechanism,we inspected the role of nano-TiO_(2) in the toxicity of Pb on Ceriodaphnia dubia(C.dubia),a model water flea species typically used for ecotoxicity studies.The effect of algae,a diet for aquatic organisms,on the effect of this binary mixture was also investigated.A two-compartment toxicokinetic(TK)-toxicodynamic(TD)modeling approach was used to quantify the Pb toxicity under these complex conditions and to develop critical parameters for understanding the mechanism of toxicity.This twocompartment modeling approach adequately described the Pb accumulation in the gut and in the rest of the body tissue under different nano-TiO_(2) concentrations,with and without algae,and predicted the toxicity response of C.dubia.It indicated that increasing the nano-TiO_(2) concentration reduced the Pb tolerance level and concurrently increased the killing rate constant of C.dubia.Therefore,nano-TiO_(2) synergistically enhanced Pb toxicity.Algae remarkably reduced the toxicity of this binary mixture through reducing the Pb transfer rate to the body tissue and the killing rate,although it did not affect the Pb tolerance level.This two-compartment modeling approach is useful in understanding the role of nanoparticles when assessing the overall toxicity of nanoparticles and other toxic elements in the environment.

赤瓟块茎淀粉的提取及理化特性研究

通过单因素试验和正交优化试验研究赤瓟(Thladiantha dubia Bunge)块茎淀粉的纤维素酶提取工艺,以马铃薯淀粉和玉米淀粉为对照品,用于赤瓟块茎淀粉的理化特性研究。结果表明,采用纤维素酶法提取赤瓟块茎淀粉的最佳工艺条件为酶解温度50℃、酶浓度0.5%、pH 5.0、酶解时间3 h,在此条件下,赤匏块茎淀粉回收率达88.75%;粗淀粉的淀粉含量为79.2%,含水量为13.0%,蛋白质含量为0.11%,脂肪含量为0.10%,灰分含量为0.65%;淀粉颗粒粒径分布呈双峰型,直径长度在2.00~50.00μm,平均粒径为35.25μm,粒径居于玉米淀粉颗粒粒径和马铃薯淀粉颗粒粒径之间;淀粉糊的透光率适中,高于市售玉米淀粉,低于市售马铃薯淀粉;析水率与市售马铃薯淀粉和玉米淀粉无显著差异;赤瓟块茎淀粉糊的冻融稳定性与马铃薯淀粉糊和玉米淀粉糊相似;溶胀起始温度和溶胀特性与玉米淀粉较相似。

赤雹根化学成分的研究

目的研究赤雹Thladiantha dubia Bunge根的化学成分。方法赤雹根45%乙醇提取物采用大孔树脂、硅胶、ODS、TLC、制备HPLC进行分离纯化,根据理化性质及波谱数据鉴定所得化合物的结构。结果从中分离得到6个化合物,分别鉴定为皂树皮酸-3-O-β-D-吡喃半乳糖-(1→2)-6-O-乙基-β-D-吡喃葡萄糖醛酸苷(1)、皂树皮酸-3-O-β-D-吡喃葡萄糖-(1→3)-β-D-吡喃葡萄糖苷(2)、皂树皮酸-3-O-β-D-吡喃半乳糖-(1→2)-[β-D-吡喃葡萄糖-(1→3)]-β-D-吡喃葡萄糖苷(3)、皂树皮酸-3-O-β-D-吡喃半乳糖-(1→2)-6-O-甲基-β-D-吡喃葡萄糖醛酸苷(4)、3-O-β-D-吡喃半乳糖基(1→2)-β-D-吡喃葡萄糖醛酸基-丝石竹酸-28-O-β-D-吡喃木糖基(1→3)-β-D-吡喃木糖基(1→4)-α-L-吡喃鼠李糖基(1→2)-α-L-吡喃阿拉伯糖苷(5)、汉黄芩素(6)。结论化合物1~3为新化合物,化合物4~6为首次从该植物中分离得到。

外源多胺对铜胁迫下水鳖叶片多胺代谢、抗氧化系统和矿质营养元素的影响

采用营养液水培的方法,研究了外源亚精胺(Spd)和精胺(Spm)对Cu胁迫下水鳖叶片3种形态多胺(PAs)、抗氧化系统及营养元素的影响。结果表明:(1)Cu胁迫使水鳖叶片腐胺(Put)急剧积累,Spd和Spm明显下降,从而使(Spd+Spm)/Put比值也随之下降。外源Spd和Spm显著或极显著逆转Cu诱导的PAs变化,抑制Put的积累,缓解Spd和Spm的下降,从而提高了(Spd+Spm)/Put比值。(2)外源Spd和Spm抑制了Cu胁迫诱导的多胺氧化酶(PAO)的增加,缓解了二胺氧化酶(DAO)的下降。(3)与单一Cu胁迫相比,Spd和Spm显著或极显著提高了超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性和抗坏血酸(AsA)、谷胱甘肽(GSH)、游离脯氨酸(Pro)含量,从而降低了超氧阴离子(O2.-)产生速率和过氧化氢(H2O2)含量,极显著降低了丙二醛(MDA)含量,缓解了Cu诱导的氧化胁迫。(4)外源Spd和Spm显著或极显著缓解了Cu胁迫下矿质营养元素吸收平衡的紊乱。以上结果均说明了外施Spd和Spm可增加水鳖对Cu胁迫的耐受性。

镧缓解镍对水鳖叶片的毒害效应研究

以水鳖叶片为实验材料,研究了重金属Ni毒害下La的缓解效应。La能缓解重金属Ni胁迫导致的水鳖(HydrocharisdubiaBL Backer)叶片叶绿素含量的降低,细胞膜透性(relativemembranepenetrability)的增加和丙二醛(MDA)的积累。加入10mg·L-1La后与同浓度的单一Ni处理相比,超氧化物歧化酶(SOD),过氧化氢酶(CAT)活性有不同程度的增强,过氧化物酶(POD)活性有所减弱,表明它增强了对活性氧的清除能力,缓解了Ni对膜的伤害;可溶性蛋白含量则保持较高的水平,脯氨酸(proline)含量刚好相反,体现出La能增强水鳖对Ni胁迫的抗性,两组不同处理差异显著。而高浓度Ni处理,La则与Ni协同,从而加快细胞死亡进程。因此,La只能缓解一定浓度Ni对水鳖的毒害(Ni<10mg·L-1),而对高浓度Ni缓解效应不明显甚至加剧毒害作用。

镉污染对水鳖的毒害影响

研究分析了不同浓度 Cd2 +对水鳖叶片叶绿素含量、SOD、CAT、POD活性以及超微结构的影响。结果表明 ,叶绿素含量、SOD、CAT、POD活性均随 Cd2 + 浓度的增加而先升后降。电镜观察发现 ,Cd2 + 处理下 ,细胞核变形 ,核仁解体 ,染色质凝集 ;类囊体片层膨胀 ,叶绿体双层膜破裂 ;线粒体中嵴突减少或消失 。

赤雹根镇痛作用及有效部位研究

目的观察赤雹根的镇痛作用并筛选其有效部位。方法采用小鼠48℃热板法和扭体法,观察赤雹根水提物、醇提物及醇提物的石油醚萃取物、氯仿萃取物、正丁醇萃取物及水溶性部分的镇痛作用。结果除石油醚萃取物以外,其余赤雹根各提取物均能明显延长热板试验小鼠痛反应潜伏期,减少ip酒石酸锑钾所致小鼠扭体次数,上述作用的主要有效部位之一为正丁醇萃取物中所含的总皂苷。结论赤雹根具有明显的镇痛作用,其所含总皂苷为其镇痛作用的主要有效部位之一。

赤雹根总皂苷对实验性佐剂型关节炎镇痛作用的研究

目的:观察赤雹根总皂苷对实验性佐剂型关节炎的镇痛作用。方法:采用弗氏完全佐剂(FCA)制备大鼠实验性佐剂型关节炎疼痛模型,分别给予赤雹根总皂苷(160、80、40mg.kg-1),以及雷公藤12mg.kg-1阳性对照药治疗,以关节炎指数、痛阈和疼痛级别为指标,评价其对实验性佐剂型关节炎的镇痛作用。结果:赤雹根总皂苷各剂量均能明显降低大鼠实验性佐剂型关节炎的关节炎指数,提高其痛阈,降低其疼痛级别。结论:赤雹根总皂苷对实验性佐剂型关节炎具有显著的镇痛作用。

Cr^(6+)污染对水鳖的叶绿素含量和几种酶活性的影响

主要研究Ｃｒ６＋污染对水鳖的外部形态及叶绿素含量、过氧化物酶活性、硝酸还原酶活性等生理指标的影响．Ｃｒ６＋对水鳖毒害结果显示是抑制其对水分的吸收，在８～３２μｇ／ｇ范围内毒害程度与处理时间和浓度呈正相关．在高浓度时短期处理的叶边缘开始出现干枯，根尖腐烂．在短期内４μｇ／ｇ，８μｇ／ｇ的Ｋ２Ｃｒ２Ｏ７能提高水鳖叶中叶绿素的含量，而１６μｇ／ｇ，３２μｇ／ｇ的Ｋ２Ｃｒ２Ｏ７则降低叶中叶绿素的含量．过氧化物酶活性则随着处理浓度的升高而升高．硝酸还原酶的活性在短期内４μｇ／ｇ最高，８μｇ／ｇ也略高于对照．１６μｇ／ｇ。