拟南芥(Arabidopsis thaliana)氮、碳离子注入诱变效应分析

采用N +、C +离子注入拟南芥 (Arabidopsisthaliana)种子 ,统计了种子的发芽指数 (发芽率和发芽势 ) ;用改良的RAPD技术对N+离子注入种子植株的DNA进行11个引物的随机片段多态性扩增。结果表明 ,合适剂量的N+、C+离子注入可使种子发芽率提高 ,两种离子注入种子的发芽率峰值 (分别为92.3 %和74.4 % )都在5×1014ions/cm2;分析N +离子注入材料发现 ,在1×1013 -1×1016ions/cm2剂量范围内 ,基因组DNA的变异率与发芽指数的变化趋势基本一致 ,变异率峰值 (9.0 % )在1×1015 ions/cm2。结果提示 ,分析低能N+离子诱变效应的最佳注入剂量在1×1014-5×1015 ions/cm2。对N+、C+离子注入的比较发现 ,一定范围内同等剂量C+离子注入的诱变率高于N +离子注入     

H~+、N~+、Ar~+注入对啤酒酵母存活率的影响及SEM和ESR研究

研究了H+ 、N+ 、Ar+ 低能离子注入酵母菌剂量对存活率的影响 ;离子注入对酵母细胞的刻蚀损伤作用和离子注入后对细胞内自由基产生的影响。结果表明 :酵母的存活率随着注入剂量的增加而减少 ,离子注入对其存活率影响程度是H+ >N+ >Ar+ ,其半致死剂量分别是 2 .1× 10 1 4 ions cm2 ,5 .5× 10 1 4 ions cm2 ,6 .8× 10 1 4 ions cm2 。随着离子注入剂量的增加对酵母细胞的损伤和刻蚀作用逐渐增大 ,刻蚀损伤作用具有不均匀性 ;离子注入后酵母细胞内自由基产额明显增加 ,随着注入剂量的增大 ,自由基的强度也增大 ,逐渐呈饱和趋势     

低能离子注入对小麦种子发芽及幼苗生理生化的影响

采用能量为25keV的N 不同剂量(2×1016 N /cm2、4×1016 N /cm2、6×1016 N /cm2、8×1016 N /cm2、12×1016 N /cm2)注入新疆小麦种子,研究了N 离子束注入新疆春小麦种子后对小麦种子的发芽率、幼苗体内的丙二醛(MDA)、可溶性蛋白、可溶性糖、叶绿素、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的影响。实验结果表明:以2×1016 N /cm2 剂量处理小麦较合适,可提高小麦种子的活力,促进种子萌发和幼苗生长。2×1016 N /cm2、4×1016 N /cm2 剂量处理对新春2号、新春11号幼苗生长有利,在这两种剂量处理下新春2号三种保护酶较新春11号敏感。     

N+离子注入对大豆种子活力及其幼苗的抗氧化酶活性影响

本文研究了用25keV N+注入丰豆103的种子后,N+离子对其种子的活力及子叶伸展后48小时和96小时的幼苗内蛋白质含量、谷胱甘肽巯基转移酶(GSH-Ts)、谷胱甘肽过氧化酶(GSH-Px)、抗坏血酸过氧化物酶(ASA-POD)活性的影响.结果表明当N+注量在2.6×1016N+/cm2～5.2×1016N+/cm2时,种子的发芽率、发芽指数、活力指数都明显提高;幼苗的可溶性蛋白含量高于对照.在6.5×1016N+/cm2～10.4×1016N+/cm2注量时,幼苗的可溶性蛋白含量低于对照,96小时幼苗可溶性蛋白的含量高于48小时,说明辐射引起的损伤可随生长时间的增加而有所恢复.高注量可引起幼苗内一些抗氧化酶活性的升高,且随注量的增加酶的活性升高也越明显,96小时幼苗的GSH-Px和ASA-POD活性高于48小时幼苗,GSH-Ts活性略有下降.而低注量(1.3×1016N+/cm2～5.2×1016N+/cm2)的上述酶指标升幅不大.说明经N+离子处理后可通过诱导这些抗氧化酶活性的升高起到减轻伤害的作用.     

氮离子束注入对燕麦M1-M2代幼苗耐盐性的影响

采用能量为25keV的不同剂量(4×1016N /cm2、6×1016N /cm2、8×1016N /cm2、12×1016N /cm2)N 注入燕麦种胚,研究N 离子束注入后,盐胁迫对燕麦M1和M2代幼苗体内超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,脯氨酸含量、丙二醛(MDA)含量、可溶性糖及可溶性蛋白含量的影响。实验结果表明:对M1代,以6×1016N /cm2剂量处理燕麦较合适,能提高燕麦受盐胁迫影响后幼苗SOD活性和可溶性糖含量。而对M2代,4×1016N /cm2处理剂量能降低MDA含量,提高可溶性糖含量,这都有利于盐胁迫后燕麦幼苗的生长。     

氮离子束注入燕麦种子对M1-M2代幼苗生理生化指标的影响

采用能量为25keV的不同剂量(4×1016N /cm2、6×1016N /cm2、8×1016N /cm2、12×1016N /cm2)N 束注入燕麦种胚,研究了N 离子束注入后,燕麦M1代和M2代种子的发芽率,幼苗体内过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性,叶绿素含量、丙二醛(MDA)含量、可溶性糖及可溶性蛋白含量的影响。实验结果表明:以12×1016N /cm2剂量处理燕麦较合适,能提高燕麦M1和M2代种子的发芽率,幼苗POD、CAT活性和可溶性蛋白含量,有利于幼苗生长。     

低能离子注入木聚糖酶产生菌黑曲霉(Aspergillus Niger)育种中参数的优化

本文对离子束技术的注入工艺和在不同能量下的不同注入剂量下黑曲霉的存活率和突变率进行了研究,目的是为了找到恰当的注入工艺和良好的注入参数,使诱变达到较好的效果。结果发现:当注入离子为氮离子时,在10keV的能量下注入剂量为5.2×1014ions/cm2和1.56×1015ions/cm2时,诱变效果较好。在这注入条件下,通过培养基优化,使木聚糖酶酶活达到600IU/ml。     

N+离子注入对干旱胁迫条件下甘草幼苗的SOD酶和CAT酶活性及丙二醛含量的影响

以低能氮离子束为诱变源,对甘草种进行注入处理后,以萌发的幼苗为材料对其在干旱胁迫条件下保护酶活性及MDA含量变化进行研究.结果表明注入后甘草种的存活率呈现马鞍形曲线变化,其中在4.1×1016N+/cm2剂量处达到鞍点,在剂量4.6×1016N+/cm2处存活率高于对照.在干旱胁迫下,随着胁迫时间的延长,离子束注入后萌发的幼苗MDA含量明显低于对照.酶活结果显示,在干旱胁迫后期,剂量4.6×1016N+/cm2处理后的甘草幼苗SOD和CAT酶活性都高于对照,说明该注入剂量处理甘草种有助于提高甘草幼苗的抗旱性能,SOD同工酶结果也证明该剂量的离子注入对干旱胁迫下同工酶谱带有所影响.     

N+注入选育产蛋白酶益生菌及其生物学效应研究

试验研究了N+注入选育产蛋白酶益生菌及其生物学效应.经N+反复注入诱变筛选,突变高产菌株的酶活由出发菌株的75.8IU.g-1提高到631.6IU.g-1;利用中心组合设计原理摸索出了突变菌株最佳产酶条件即麸皮24.83%,豆粕23.68%,水50%,硫酸铵1.49%,发酵温度30℃,发酵时间66h,培养基pH 5.5.生物学效应研究发现真空处理对活细胞有明显伤害;孢子存活率先是随着注入剂量加大而迅速降低,当注入剂量加大到50×2.6×1013 ions/cm2时存活率出现平缓回升,注入剂量超过100×2.6×1013ions/cm2时存活率又再次开始下降;注入剂量越大,孢子突变率越高,中等注入剂量30×2.6×1013N+/cm3～80×2.6×1013N+/cm2可引起较高的正突变率;ESR谱研究结果表明,N+注入前和注入后都有自由基ESR波谱单一峰,随着注入剂量的增大,孢子内的自由基ESR波谱的强度也逐渐增大;SEM观察发现,未经N+注入的孢子较为完整、饱满且表面光滑,而经注入后的孢子表面粗糙,可见明显的刻蚀损伤和破壁现象,并且注入剂量越大,伤痕也越深宽.试验结果提示N+注入是一种有效的动物益生菌选育方法.     

离子注入对小麦当代形态生理影响的初步研究

采用能量为30keV的N+不同剂量(8×1017N+/cm2、10×1017N+/cm2、12×1017N+/cm2)注入小麦种子,研究了离子注入后形态生理变化。结果表明:1.离子注入后小麦的出苗率随着剂量的增加而下降,但均大于80%;2.对麦苗生长有明显的抑制作用;3.离子注入后表皮细胞结构有明显的改变;随着剂量的增加,表皮细胞损伤越来越严重。而且苗期表现和表皮细胞损伤程度是相对应的。     

低能离子在植物样品中长程穿透行为的研究

采用透射法测量了一定厚度的植物样品在接受低能离子辐照时从其后表面出射的荷能粒子。所测样品包括30、50和100μm芸豆子叶切片和20μm的西红柿皮,测量结果表明低能离子在植物样品中存在长程穿透现象,在芸豆切片中的穿透深度至少可达60μm,此时穿透的概率很小,大于10^-5;长程穿透的离子产生的损伤空间分布不均匀。样品的高能质子透射能谱显现辐照损伤不是特别严重,推测这种长程穿透的现象由植物样品本身的结构决定。     

Effects of atmospheric small negative ions on the oxygen consumption of mouse liver cells

The effects of small negative air ions on the oxygen uptake of isolated mouse liver cells were studied by exposing the liver cells to varying ion concentrations. For concentrations of the order of 1–2 × 10⁵ ions/cm³, the oxygen uptake was always higher than in the normal atmospheric conditions of 3–8 × 10²/ions/cm³. For intermediate concentrations varying effects of activation and inhibition were observed. A statistical analysis showed that the oxygen uptake increased by approximately 14% when liver cells were exposed to ion concentrations of values 1–9 times the normal, by approximately 9% when exposed to 10–99 times the normal, and by approximately 38% when exposed to 100–999 times the normal. The significance and possible implications of the results are discussed.     

Anchorage-dependent mammalian cell culture using polyurethane foam as a new substratum for cell attachment

Summary Anchorage-dependent mammalian cells were cultivated at high cell density in a novel culture system using polyurethane foam (PUF) as a substratum for cell attachment. PUF has a macroporous structure giving a high surface area to volume ratio. Monkey kidney cells (Vero) and Chinese hamster ovary cells (CHO-K1) attached to the internal surface of PUF and grew to a high cell density (1.04 × 10⁸ cells/ cm³ PUF and 3.5 × 10⁷ cells/ cm³ PUF, respectively) in PUF stationary cultures. In addition, we have designed a PUF-particle packed-bed culture system for high density mass cell culture. A maximum cell density of 2.4 × 10⁷ cells/cm³ culture vessel volume was obtained in a packed-bed culture of Vero cells. Offprint requests to: K. Funatsu     

Evidence for salt diffusion from sediments contributing to increasing salinity in the Salton Sea, California

Geochemical investigations of interstitial waters from the Salton Sea, CA reveal evidence of concentrated brines in the sediments underlying the lakes two basins. The brines are likely caused by the gradual dissolution of evaporite deposits. The chemical composition of the brine in the northern basin is dominated by magnesium and sulfate and differs from the southern basin where the dominant components are sodium and chloride. Sediment depth distributions of major ions and porosity indicate diffusion of salts from the sediments into the overlying waters in both basins. Benthic fluxes have been calculated for the four most abundant ions: magnesium, sodium, sulfate and chloride. For the northern basin we calculate diffusive fluxes of 3.7 × 10^–2, 8.2 × 10^–2, 44 × 10^–2, and 5.4 × 10^–2 g cm^–2 yr^–1 for magnesium, sodium, sulfate and chloride, respectively. For the southern basin we calculate diffusive fluxes of 0.9 × 10^–2, 9.7 × 10^–2, 6.9 × 10^–2, and 25 × 10^–2 g cm^–2 yr^–1 for these same ions. By scaling up our results we estimate the salinity flux from the sediment to the water column to be between 3.6 × 10⁴ and 3.6 × 10⁵metric tons per year, equivalent to 1–10% of the riverine input. These results are important for developing strategies to combat rising salinity in the Salton Sea, CA.     

High density culture of anchorage-dependent animal cells by polyurethane foam packed-bed culture systems

Summary Monkey kidney cells (Vero) and Chinese hamster ovary cells (CHO-K1) attached to the internal surface of polyurethane foam (PUF) and grew to a high cell density (1.1 × 10⁸ cells/cm³ PUF and 4.2 × 10⁷ cells/cm³ PUF, respectively) in a PUF-plates packed-bed culture system. This density of Vero cells was twice that obtained previously with a PUF-particles packed-bed culture system. A maximum cell density of 6.7 × 10⁷ cells/cm³ culture vessel volume was obtained in a PUF-disc packed-bed culture of Vero cells. From the cell density of CHO-K1, growing in a monolayer on the surface of PUF and a petri dish, per bulk volume of PUF, we estimated that a surface area to volume ratio of PUF plates effective for cell growth was about 109 cm²/cm³.Offprint requests to: K. Funatsu     

The effect of air ions on bacterial and viral pneumonia in mice

Ambient air untreated for removal of ordinary pollutants and ionized with tritium powered generators to contain 1–2 × 10⁵ small positive ions/cm³ accelerated the rate of death of mice challenged intranasally with measured doses of KLEBSIELLA PNEUMONIAE or of the PR8 strain of influenza virus. The differences between the cumulative mortality rates of controls and ion-treated animals were significant (p < 0.05 to p < 0.001) for several days of the period of observation. Exposure of infected mice to an electrical field of the same strength as that used for ion-treated mice showed no statistically significant field effect. Repetition of the influenza virus experiments using pollutant-free air and ion densities averaging 4.1 × 10⁵ small positive ions/cm³ produced essentially the same results. The observation that high concentrations of positive ions accelerate the rate of death in pulmonary infections with KLEBSIELLA PNEUMONIAE and with influenza virus conforms to the pattern of earlier work with COCCIDIOIDES IMMITIS.

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Zusammenfassung Ungereinigte Umgebungsluft mit 1–2 × 10⁵ kleinen positiven Ionen/cm³ nach Ionisation mit Tritiumbetriebenen Generatoren beschleunigte die Todesrate von Mäusen, die intranasal mit bekannten Mengen KLEBSIELLA PNEUMONIAE und PR8 Influenza Virus okuliert worden waren. Die Unterschiede zwischen den Kontrolltieren und den ionenbehandelten Tieren waren an mehreren Beobachtungstagen signifikant (p < 0,05 bis p < 0,001). Die Exponierung der infizierten Tiere in einem elektrischen Feld der gleichen Stärke, wie für die ionenbehandelten Tiere verwendet wurde, ergab keine statistischen Unterschiede. Die Wiederholung der Versuche mit Influenza Virus in reiner Luft mit 4,1 × 10⁵ kleinen positiven Ionen/cm³ ergab die gleichen Ergebnisse.

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Resume De l'air non purifié additionné de 1–2 × 10⁵ petits ions positifs/cm³ — ions provenant de générateurs au Trititium — a augmenté le taux de décès de souris qu'on avait au préalable infectées par le nez de quantités déterminées de KLEBSIELLA PNEUMONIAE et de virus d'influenza PR8. La différence du taux cumulatif de mortalité entre des animaux traités avec cet air ionisé et des témoins a été significative pour chacun des jours de la période d'essais (p < 0,05 à p < 0,001). L'exposition de souris infectées à un champ électrique de même intensité que celui utilisé pour les animaux traités n'a pas présenté d'effets significatifs. La répétition de l'essai avec le virus de l'influenza, mais en utilisant de l'air libre de tout polluant et une densité d'ions moyenne de 4,1 × 10⁵ petits ions positifs/cm³ a conduit à des résultats similaires. La constatation que de hautes concentrations en ions positifs augmente le taux de décès dûs à des infections pulmonaires avec KLEBSIELLA PNEUMONIAE et avec le virus de l'influenza vient confirmer le résultat d'un essai antérieur pratiqué avec COCCIDIOIDES IMMITIS.

     

Potato slab dehydration by air ions from corona discharge

Space charge (air ions) produced by single corona electrodes was used to enhance drying rates from fresh slabs of potato. The drying path was traced by a beta-ray gauge which provided both sensitivity and reproducibility to the measurements of drying time. The rate of evaporation was increased 2.2 to 3.0 times when subjected to fluxes of 3.02×10¹² positive ions alone or in combination with 7.31×10¹² negative air ions/cm² per s compared to that from an air-drying control slab. Electric wind caused by an ionic drag force seems to be the principal driving force for the observed enhancement in drying rates.     

Optimal cell density and multiplicity of infection for the propagation of human rotavirus in monkey kidney cells

The human rotavirus titer was optimal at an infection cell density of about 4–8 × 10⁴ cells cm^–2 in monkey kidney cell cultures. The highest viral titers (3.8 × 10⁷ TCID₅₀ ml^–1 and 3.7 × 10⁷ TCID₅₀ ml^–1) were obtained at an multiplicity of infection of 0.05 in well plate and T-flask, respectively.     

Flux and grain size variation of eolian dust as a proxy tool for the paleo-position of the Intertropical Convergence Zone in the northeast Pacific

A 328 cm-long piston core (KODOS 02-01-02) collected from the northeast equatorial Pacific at 16°12′N, 125°59′W was investigated for eolian mass fluxes and grain sizes to test these proxies as a tool for the paleo-position of the Intertropical Convergence Zone (ITCZ). The eolian mass fluxes of the lower interval below 250 cm (15.5-7.6 Ma) are very uniform at 5 ± 1 mg/cm²/10³ yr, while those of the upper interval above 250 cm (from 7.6 Ma) are over 2 times higher than the lower interval at 12 ± 1 mg/cm²/10³ yr. The median grain size of the eolian dusts in the lower interval increases from 8.4? to 8.0? downward, while that of the upper interval varies in a narrow range from 8.8? to 8.6?. The determined values compare well in magnitude to those of central Pacific sediments for the upper interval and equatorial and southeast Pacific sediments for the lower interval. This result suggests a possibility that the study site had been under the influence of southeast trade winds at its earlier depositional period due to the northerly position of the ITCZ, and subsequently of the northeast trade winds for a later period when the upper sediments were deposited. This interpretation is consistent with a mineralogical and geochemical study published elsewhere that assigned the provenance of the study core dust to Central/South America for the lower interval and to Asia for the upper interval. This study suggests that the distinct differences in eolian mass flux and grain size observed across the ITCZ can be used to trace the paleo-latitude of the ITCZ.