富铬酵母的理化性质和氨基酸分析*

用２００～３００ｎｍ的波长范围对富铬酵母及普通酵母的溶液进行紫外扫描,发现在λ_{２６０ｎｍ}处有一特征紫外吸收峰,富铬酵母细胞的铬含量与其吸收峰的光密度呈线性关系;在不同的温度和ｐＨ值条件下,通过紫外吸收峰的测定,富铬酵母溶液在酸性条件下稳定,在碱性条件下不稳定。溶液的λ_{２６０ｎｍ}紫外吸收峰随着温度的上升而升高。从氨基酸含量分析结果看,富铬酵母的谷氨酸、甘氨酸、组氨酸、丙氨酸和赖氨酸含量高于普通酵母,但其他氨基酸含量比普通酵母低。     

HPLC快速测定氨基酸口服液中的L—色氨酸

本文用ＨＰＬＣ直接测定Ｌ—色氨酸,简便快速,波长２８０ｎｍ,线性良好（ｒ＝０．９９９９）,平均回收率：１００．０１％,ｎ＝４,ｃｖ＝０．６０％。     

富铬酵母的理化性质和氨基酸分析

用２００～３００ｎｍ的波长范围对富铬酵母及普通酵母的溶液进行紫外扫描,发现在λ_(２６０ｎｍ)处有一特征紫外吸收峰,富铬酵母细胞的铬含量与其吸收峰的光密度呈线性关系;在不同的温度和ｐＨ值条件下,通过紫外吸收峰的测定,富铬酵母溶液在酸性条件下稳定,在碱性条件下不稳定。溶液的λ_(２６０ｎｍ)紫外吸收峰随着温度的上升而升高。从氨基酸含量分析结果看,富铬酵母的谷氨酸、甘氨酸、组氨酸、丙氨酸和赖氨酸含量高于普通酵母,但其他氨基酸含量比普通酵母低。     

QS激光治疗面部雀斑临床疗效观察

用ＱＳＮＤ ＹＡＧ倍频５３２ｎｍ及ＱＳ翠绿宝石７５５ｎｍ波长激光一次治疗面部雀斑。研究：观察哪些波长组合及用何方法在临床应用既能达到美容效果、又能缩短疗程、节约费用。在将近选患者面部色素密度均匀部位分左、中、右区域进行治疗观察后,发现：（１）ＱＳ５３２ｎｍ治疗组６个月疗效达４０．５％（Ｐ〈０．０５）,（２）ＱＳ７５５ｎｍ治疗组６个月疗效达１２％（Ｐ〈０．０５）,（３）ＱＳ５３２ｎｍ＋ＱＳ７５ｎｍ治疗组疗效达７２％（Ｐ〈０．０１）。说明采用两种波长激光同时复合治疗疗效好,而且起到了美容效果,临床值得推广。     

活细胞染色体切割（光刀）和光捕捉（光钳）的研究

本文报道了光捕捉活细胞染色体的最新实验结果。对ＰＴＫ＿２有丝分裂细胞的染色体先围激光刀切割,再用光钳捕捉使该切割的染色体片断的行为发生改变。光捕捉中期切割的染色体片断有可能使它们整合到同一个子细胞中或丢失在分裂沟中。光捕捉后期切割的染色体可使该切割片断或掺入相反的细胞中或丢失在分裂沟中或回到原有的相应子细胞中。光捕捉操纵染色体去水螈肺上支子细胞中不仅同样有效,还可以在纺缍体的边缘,即纺缍体和间丝笼之间的细胞质清澈区域内用光钳操纵染色体片断移动,旋转。根据细胞和染色体形态和行为,对７００－８４０ｎｍ波长范围内的各种波长的光捕捉进行了比较,结果表明,７００ｎｍ或８００－８２０ｎｍ波长操纵的细胞,出现最少的异常细胞百分率,７６０ｎｍ则诱发百分之百的异常细胞率。根据各方面的综合比较,７００ｎｍ为最佳波长,共次为１０６０和８００ｎｍ。７６０ｎｍ损伤细胞最严重,应避免使用。文中并讨论了光捕捉染色体的应用前景。     

盐生杜氏藻细胞光合特性的研究

研究了盐生杜氏藻细胞的光合特性获知：⑴在７００－３００ｎｍ波长范围,出现三个吸收峰,分别位于６８０．４８５和４００ｎｍ处;⑵测定了该藻细胞内ＡＴＰ／ＡＤＰ比值,钒酸钠处理可以提高ＡＴＰ／ＡＤＰ比值;⑶以培养液为反应介质,测出该藻细胞的光合放氧,钒酸钠抑制放氧速率;⑷用调制式荧光计测出该藻细胞的Ｆｏ,Ｆｍ以及经间隔饱和光脉冲引起的Ｆｍ,表明盐生杜氏藻具有正常的光系统结构;⑸该藻细胞可诱导可逆的光状态     

褐藻77 K荧光特异性研究

测定了裙带菜、叉开网地藻、海带、囊藻、海蒿子、鼠尾藻、萱藻和水云等８种褐藻的７７Ｋ荧光光谱并同菠菜和红藻条斑紫菜作了比较。结果表明与红藻和高等植物明显不同,褐藻没有作为ＰＳＩ特征的７３０ｎｍ荧光峰。按荧光主峰的波长,可以分为二种类型：裙带菜、叉开网地藻、海带和囊藻的荧光主峰位于６９０ｎｍ,海蒿子、萱藻、水云和鼠尾藻的荧光主峰在７０５～７２０ｎｍ。这种７７Ｋ荧光特异性预示褐藻同高等植物之间在ＰＳＩ结构上的差异。     

激光与DNA作用系统非线性共振实验初探

用紫外可见分光光度计,对受Ｈｅ－Ｎｅ激光辐照过的ＤＮＡ溶液进行扫描。发现２０９ｎｍ吸收峰降低了１０％,表明６３２．８ｎｍＨｅ－Ｎｅ激光波ＤＮＡ吸收而引起其构象变化。Ｈｅ－Ｎｅ激光波长６３２．８ｎｍ,约为２０９ｎｍ的３倍,恰好为我们理论研究的激光与ＤＮＡ相互作用非线性系统的超谐波共振波长。因此该实验结果使我们的理论结果得到了初步验证。     

多管藻R-藻红蛋白的激光光敏作用对体外培养的肿瘤细胞生存率的影响

用１００μｇ／ｍｌ藻红蛋白联合激光处理８１１３人口腔上皮癌细胞,ＭＴＴ比色法测定癌细胞存活率。实验表明,先用藻红蛋白处理再经波长为４８８ｎｍ,２５．６Ｊ／ｃｍ２氩离子激光辐照,细胞存活率为２５％;而单用藻红蛋白,单用激光组分别为４３％和１０７％。结果证明,藻红蛋白的光敏作用对体外培养的肿瘤细胞具有较强的杀伤作用。     

荧光光谱法研究铈离子与二棕榈酰磷脂酰胆碱（DPPC）脂质体的相互作用

通过荧光光谱法研究了稀土元素Ｃｅ３＋与二棕榈酰磷脂酰胆碱（ＤＰＰＣ）脂质体的相互作用,结果表明,Ｃｅ３＋－ＤＰＰＣ体系的激发波长在２４７ｎｍ,２９４ｎｍ,发射波长在３４４ｎｍ,与水合Ｃｅ３＋的荧光光谱完全不同。这表明Ｃｅ３＋与ＤＰＰＣ形成了复合物,该复合物的荧光光谱同Ｃｅ３＋－ＤＨＰ复合物的荧光光谱一致。可以认为Ｃｅ３＋与ＤＰＰＣ分子上的磷酸基团相作用。     

红光与远红光比值对切花菊‘神马’发育和外观品质的影响

为了探讨不同R/FR值对温室切花菊发育进程和品质的影响,以切花菊品种‘神马’(Chrysanthemum morifoliumcv.‘Jingba’)为试材,设计不同红光(R:660nm!10nm)与远红光(FR:730nm!10nm)比值(R/FR)为0.5、2.5、4.5、6.5的LED灯照射处理试验,以自然光为对照(CK),观测不同处理的菊花发育阶段和品质指标。结果表明:与CK相比,R/FR=2.5处理显著加快菊花的发育进程(P<0.05),R/FR=2.5处理下短日照处理到现蕾、现蕾到破蕾及破蕾到收获3个发育阶段分别比CK提前4d、8d和5d,R/FR=0.5处理发育速度最慢,3个阶段分别比CK晚4d、2d和2d;不同R/FR值处理下菊花株高、单株叶龄、单株叶面积、茎粗、花径和花梗长度均随温光效应的增加呈增加的趋势,并在R/FR=2.5时取得最大值;收获时切花菊达到A级和B级产品等级的比例分别以R/FR=2.5和4.5处理最高。本研究发现,R/FR为2.5能够显著促进菊花发育进程和提高菊花的外观品质和A级切花的比例。     

完整叶片内玉米黄质的分光光度分析

以载玻片作参比材料,成功地解决了较厚叶片不能直接测定505 nm光吸收来反映玉米 黄质水平的难题。并通过对银杏叶片505 nm光吸收的不同方法测定分析比较,表明该方法测 定结果稳定可靠。     

完整叶片内玉米黄质的分光光度分析

以载玻片作参比材料,成功地解决了较厚叶片不能直接测定505nm光吸收来反映玉米黄质水平的难题。并通过对银杏叶片505nm光吸收的不同方法测定分析比较,表明该方法测定结果稳定可靠。     

Nonspecific light loss and intrinsic DNA variation problems associated with feulgen DNA cytophotometry.

Nonspecific light loss by the cell-wall-plus-cytoplasm (CWC) can cause a 50% increase in Feulgen absorption units in peanut root-tip nuclei as determined by scanning at 450 nm, whereas this phenomenon is not evident with chicken erythrocytes. A two wavelength scanning method of subtracting nonspecific 450 nm absorption from 550 nm Feulgen absorption values eliminated the nonspecific light loss in CWC, However, the two wavelength scanning method is time consuming and somewhat impractical with a regular scanning microdensitometer such as Vickers M85. Elimination of the problem of nonspecific light loss is suggested by careful determination of background setting with the spot position close to the nucleus in CWC. The accuracy of the CWC background setting method was further tested by comparison with subtraction method. The use of plant nucleis as an internal standard in plant DNA measurements was also evaluated. Significant variation among the replicate slides due to the variation in pine nuclear DNA amounts was observed and plant nuclei generally are not reliable internal standards. Mature chicken erythrocytes are recommended as an internal standard because the cell type and metabolic state is known.     

Characterization of the laser-induced blue, green and red fluorescence signatures of leaves of wheat and soybean grown under different irradiance

The blue, green and red fluorescence emission of green wheat ( Triticum aestivum L. var. Rector) and soybean leaves ( Glycine max L. var. Maple Arrow) as induced by UV light (nitrogen laser: 337 nm) was determined in a phytochamber and in plants grown in the field. The fluorescence emission spectra show a blue maximum near 450 nm, a green shoulder near 530 nm and the two red chlorophyll fluorescence maxima near 690 and 735 nm. The ratio of blue to red fluorescence, F450/F690, exhibited a clear correlation to the irradiance applied during the growth of the plants. In contrast, the chlorophyll fluorescence ratio, F690/F735, and the ratio of blue to green fluorescence, F450/F530, seem not to be or are only slightly influenced by the irradiance applied during plant growth. The blue fluorescence F450 only slightly decreased, whereas the red chlorophyll fluorescence decreased with increasing irradiance applied during growth of the plants. This, in turn, resulted in greatly increased values of the ratio, F450/F690, from 0.5 – 1.5 to 6.4 – 8.0. The decrease in the chlorophyll fluorescence with increasing irradiance seems to be caused by the accumulation of UV light absorbing substances in the epidermal layer which considerably reduces the UV laser light which passes through the epidermis and excites the chlorophyll fluorescence of the chloroplasts in the subepidermal mesophyll cells.     

城市绿地生态保护视角昆虫光谱趋性差异

照明提升城市夜间安全与活力,是城市建设的重要因素。但近年来夜间照明的迅速蔓延,改变了城市自然环境的光周期与光分布范围,造成光污染生态风险。其中,趋光昆虫受到的胁迫尤为显著,城市绿地昆虫种类与数量急剧下降,进而通过级联效应,引发城市绿地生态系统失衡问题。昆虫是典型的生态指示种和光敏动物,明确昆虫的光谱趋性差异,筛选出对昆虫趋光性友好的光谱,可为生态光源的研发提供依据,从而降低城市照明的生态风险。已有研究较多采用实验室内实验箱的设置方法,探究某一特定昆虫属种的趋光行为,尚缺乏对特定生境下的昆虫群落和典型昆虫目的光谱趋性研究。因此,研究在天津市津南区天津大学北洋园校区绿地系统开展野外人工光诱捕昆虫实验,以野外诱捕昆虫的种类与数量为判定依据,分析各光谱的昆虫趋性差异。野外诱虫实验以7种窄光带光谱(单色光)为研究对象,采用相对评价法,设置趋光昆虫最敏感的紫外光(Ultraviolet,369 nm)为对照组。结果表明,天津城市绿地生境中,4类典型趋光昆虫为双翅目(61.1%)、半翅目(19.7%)、鞘翅目(11.1%)、鳞翅目(5.7%)类,占诱捕总量的97.6%;对照紫外光(Ultraviolet,369 nm),4种典型昆虫总体的趋性敏感光谱排序及趋性概率为:远红色光(Far Red,740 nm)0.5%＜深红色光(Deep Red,660 nm)2.0%＜橘红色光(Red Orange,627 nm)9.0%＜青色光(Cyan,500 nm)22.8%＜绿色光(Green,519 nm)22.9%＜蓝紫色光(Royal Blue,447 nm)27.6%＜蓝色光(Blue,478 nm)40.1%;绝对生态光谱为红光,相对生态光谱为青色光(Cyan,500 nm)和蓝紫色光(Royal Blue,447 nm)。在全面推进人与自然和谐共生的现代化建设阶段,研究将有助于生态光源的开发、生态保护和城市光生态建设的提升。     

Photocatalytic antibacterial effects on TiO2-anatase upon UV-A and UV-A/VIS threshold irradiation

Photocatalysis mediated by the anatase modification of titanium dioxide (TiO₂) has shown antibacterial effects in medical applications. The aim of this study was to investigate the possibility of expanding the excitation wavelengths for photocatalytic antibacterial effects from ultraviolet (UV) into the visible light range. After deposition of salivary pellicle and adhesion of Streptococcus gordonii on anatase, different irradiation protocols were applied to induce photocatalysis: ultraviolet A (UV-A) > 320 nm; ultraviolet/visible (UV-A/VIS) light > 380 nm and > 390 nm; and VIS light 400–410 nm. A quartz crystal microbalance with dissipation (QCM-D) tests and microscopic examination were used to observe the photoinduced antibacterial effects. Salivary pellicle could be photocatalytically decomposed under all irradiation protocols. In contrast, effective photocatalytic attack of bacteria could be observed by UV-A as well as by UV-A/VIS at 380 nm < λ < 390 nm only. Wavelengths above 380 nm show promise for in situ therapeutic antifouling applications.     

光质、光强对入侵植物紫茎泽兰种子萌发及幼苗状态的影响

为了探讨紫茎泽兰种子需光萌发特性,对光质（不同颜色、红光/远红光）和光强对种子萌发率及幼苗状态进行了研究。研究发现：不同颜色光对发芽率影响显著,其中黄光、橙光和红光等波长在（591~750 nm）之间的光更有利于提高种子的萌发率（74.3%~83.3%）,而较短波长的光（<570 nm,紫光、蓝光和绿光）促进效果显著降低（62.3%~66.7%）（p<0.05）。光强对紫茎泽兰种子发芽和幼苗影响较光的颜色更具有规律性。黑暗条件下发芽率22%,随着光照提高,发芽率指数增加(r²=0.96),芽长指数下降(r²=0.99)、根长指数增加(r²=0.98),而鲜重呈现线性增加(r²=0.70)。适量红光（630 nm）和远红光（730 nm）照射能够打破和引起休眠,红光照射量与发芽率提高量成线性正相关（r²=0.98）,而远红光照射率与发芽率降低量呈线性正相关（r²=0.92）,说明紫茎泽兰需光萌发是一个光敏色素引起的过程。紫茎泽兰通常在裸地和人为干扰土壤上泛滥,这可能与其种子需光萌发有关。而对其生态学控制可以考虑从光强、特别是光质角度（如人工造林）控制种子萌发来实现。     

Effect of Different Light Quality on Photosynthetic Characteristics of Cucumber Leaves

Cucumber (Cucumis sativus L. cultivar "Changchun Mici") seedlings were cultured in Hoagland solution under irradiation with different light spectra (8 h per day) for 20 days. The red light (λmax 658 nm, λ1/2 25 nm), blue light (λmax 450 nm, λ1/2 43 nm) and white fluorescent light possessed the same fluent rate (20 μmol· m-2·s-1 ). The experimental results showed that chlorophyll content of the leaves grown under white light was 7 % and 22.4% higher than those in red and blue light, respectively. Compared with white and blue light, red light induced a lower Chl a/b ratio and a higher level of Chl b in the cucumber leaves. Measurements of the low temperature (77 K) fluorescence emission spectra and kinetics of Chl a fluorescence induction of the leaves proved that the leaves grown under red light expressed the highest PSⅡ and the lowest PSⅠactivities while the leaves under blue light had the lowest PSⅡand the highest PSⅠ activities. The O2 evolution rate of red light-grown leaves was 44.9% higher than that of the white light-grown leaves, while blue light effect was similar to that of white in respect of O2 evolution. It is concluded that light quality is an important factor in regulating the development and activities of PSⅡ and PSⅡand the O2 evolution of photosynthesis in cucumber leaves.     

基于高光谱的苹果果期冠层光谱特征及其果量估测

苹果冠层光谱特征是苹果树遥感生理监测和生产管理的重要依据。对栖霞市苹果果期的冠层反射光谱进行实测,结合数码照相技术探明了苹果果期的反射光谱特性和敏感波段,并通过敏感波段与果树比指标建立回归模型,实现了对苹果冠层果量(果树比)的无损估测。结果表明:苹果树果期冠层光谱曲线总体表现为对蓝光和红光的吸收及对绿光的反射,在近红外750—1300nm之间表现为强烈的反射,且在1650nm和2200nm附近呈现两个反射峰。选择435、670、730、940、1140nm和1480nm等6个波段为苹果果期的敏感波段。利用这些波段分别构建了差值、比值及归一化植被指数,筛选了最佳光谱参数,进而构建了果量(果树比)估测模型,经筛选验证确定苹果果量的最佳估测模型为:y=0.0086[NDVI(940,730)]2-1.0934NDVI(940,730)+0.3209。模型为苹果果期果量的精确估测提供了比较快捷的方法途径。