油梨果实的生长和内含物变化的观察

本文报道对油梨果实的生长及内含物的变化的观察结果．果实生长发育过程中,以６—７份生长最快,干物质及脂肪含量由低到高变化,以１１月份增加最快,蛋白质含量由高到低递诚．１１月份后含量相对稳定,总糖和维生素Ｃ含量随果实的发育程度而下降。     

质体醌重组的D1／D2／Cytb559复合物的荧光衰减动力学和光破坏作用

光系统Ⅱ反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 在分离纯化过程中失去了电子受体ＱＡ 和ＱＢ,人工合成的质体醌可以与Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 复合物发生重组。癸基质体醌（ＤＰＱ）与Ｄ１／Ｄ２／Ｃｙｔｂ５９９ 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命（２４ ｎｓ和７３ ｎｓ）荧光衰减组分占整个荧光的百分数下降,这些结果表明ＤＰＱ作为Ｐｈｅｏ－ 的电子受体,限制了Ｐ６８０＋ ·Ｐｈｅｏ－ 的电荷重组。ＤＰＱ 的加入对Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物中Ｃｈｌａ 分子的光破坏敏感性影响不大,但β－胡萝卜素在加入ＤＰＱ 之后可以被光照破坏,这个过程可能与β－胡萝卜素的生理功能相关。     

Mother-cub relationships in giant pandas in the Qinling Mountains,China, with comment on rescuing abandoned cubs

Six cases of mother-cub relationships in wild giant pandas (Ailuropoda melanoleuca) were observed in the Qinling Mountains, China. It was found that panda cubs are normally left alone in the den for 4–8 h while mothers forage. The mother's absence during bouts of foraging should be considered when rescuing abandoned cubs in order to avoid adding to the decline of the wild population. © 1994 Wiley-Liss, Inc.     

生态环境对川芎产、质量的影响

生态环境对川芎产、质量的影响丁德蓉,陈兴福,卢进,黄文秀,刘岁荣（四川省中医药研究院药物种植研究所,南川６４８４０８）ＩｎｆｌｕｅｎｃｅｏｆＥｃｏｅｎｖｉｒｏｎｍｅｎｔｏｎｔｈｅＹｉｅｌｄａｎｄＱｕａｌｉｔｙｏｆＬｉｇｕｓｔｉｃｕｍｃｈｕａｎｘｉｏｎ...     

人骨骼肌α辅肌动蛋白（α－actinin）的提取及其抗血清的制备和鉴定

本文提取人骨骼肌α辅肌动蛋白（α－ａｃｔｉｎｉｎ）是综合了文献报导有关提取兔肌α－ａｃｔｉｎｉｎ的和提取鸡胗α－ａｃｔｉｎｉｎ的方法,稍加修改而确定的。用Ｈａｓｓｅｌｂａｃｈ－Ｓｃｈｎｅｉｄｅｒ缓冲液提取骨骼肌中的肌球蛋白后,将残余物经硼酸－缓冲液提取、匀浆及高速离心去掉肌动蛋白和肌原纤维的其它成份,上清加硫酸铵至３０％,３５％饱合度所得的沉淀用２２０ｍｍｏｌ／ＬＴｒｉｓ－乙酸溶解、透析、离心后经ＤＥ－５２柱层析可得电泳纯。α－ａｃｔｉｎｉｎ。将人骨骼肌α－ａｃｔｉｎｉｎ纯化制品免疫了三只大耳白纯种家兔,两个多月后,三只兔子都产生免抗人骨骼肌α－ａｃｔｉｎｉｎ的特异抗血清,用双向免疫扩散法和酶联免疫吸附试验（ＥＬＩＳＡ）测定,产生的抗体效价较高,用双扩散法测定效价为１：３２,用ＥＬＩＳＡ测定,用比率法判断结果,效价最高者为１：１００,０００左右,经免疫电镜观察结果证实,上述抗血清可以满足进一步实验要求。     

Glycosphingolipid acyl chain orientational order in unsaturated phosphatidylcholine bilayers.

The glycosphingolipid, galactosyl ceramide (GalCer), was studied by 2H nuclear magnetic resonance (NMR) in fluid phospholipid bilayer membranes, with regard to arrangement of its acyl chain. For this purpose, species with perdeuterated 18-carbon fatty acid (18:0[d35]GalCer) or with perdeuterated 24-carbon fatty acid (24:0[d47] GalCer) were dispersed in bilayers of the 18-carbon phospholipid, 1-stearoyl-2-oleoyl-phosphatidylcholine (SOPC). For 18:0[d35] GalCer, smoothed profiles of the order parameter, SCD, were found to be very similar to one another over the range of glycolipid concentration, 5-40 mol%. In addition, they were very similar to orientational order parameter profiles well known from the literature on phospholipid and glycolipid acyl chains (which deals in general with membranes of homogeneous chain length in the range 14-18 carbons). Corresponding order parameter profiles for the long-chain species, 24:0[d47] GalCer, were also similar to one another for glycolipid concentrations between 5 and 40 mol%. Their shapes, however, were distinctly different from those of the shorter chain analogues. SCD profiles for the two species were quantitatively similar to a membrane depth of C15. SCD values at C16 and C17 were approximately 20 and 30%, respectively, higher for the long-chain glycosphingolipid than for its short-chain analogue in SOPC. Nitroxide spin labels attached rigidly to C16 of the long-chain glycolipid in SOPC gave electron paramagnetic resonance (EPR) order parameters that were twice as high as for a spin label at C16 on the shorter chain glycolipid. Comparison was made between spectra of 24:0[d47] GalCer in SOPC and fully hydrated bilayers of the pure 24:0[d47] GalCer, a system that is considered to be partially interdigitated in fluid and gel phases. The resultant 2H NMR order parameter profiles displayed similar features, indicating that related organizational properties exist in these fluid systems. Effective chain length of 24:0[d47] GalCer within the SOPC membrane was calculated using the method of Schindler and Seelig (1975. Biochemistry, 14:2283-2287). The result suggested that the long-chain fatty acid should protrude roughly one third of the host matrix chain length across the bilayer midplane. However, a treatment of the same order parameters making very few assumptions about chain conformation indicated a high degree of orientational flexibility for the "extra" length of the long chain fatty acid.(ABSTRACT TRUNCATED AT 400 WORDS)     

Isozyme variation and species relationships in peanut and its wild relatives (Arachis L. — Leguminosae)

Summary Arachis hypogaea (peanut or groundnut) is an AABB allotetraploid whose precise ancestry is not yet clear. Its closest diploid relatives are the annual and perennial wild species included with it in the section Arachis. Variation in these species for 11 different enzymes was studied by starch-gel electrophoresis. Differences attributed to at least 13 genetic loci were found among eight enzymes, while three enzymes appeared uniform throughout the section. Values for Nei's genetic distance were calculated for all pairs of species and were used to estimate relationships. All diploid species, apart from two whose validity had previously been questioned, could be distinguished by their overall zymotypes, but few contained unique alleles. When species were grouped by their mean genetic distances, they formed two clusters, which agreed reasonably well with the division of the section into annual versus perennial species. The single B-genome species was an outlier within the annual group. A. hypogaea showed fixed heterozygosity at four loci (in ssp. hypogaea) or six loci (in ssp. fastigiata), which agrees with previous conclusions that the peanut is an allotetraploid. None of the diploids included in this survey could be conclusively identified as donors of either the A or the B genome to the tetraploids. The two subspecies of A. hypogaea differed consistently in two of the thirteen putative loci studied. This may call into question the simple hypothesis that A. hypogaea originated from just two diploid species.     

The use of thidiazuron in tissue culture

Summary Thidiazuron (N-phenyl-N’-1,2,3-thiadiazol-5-ylurea) was first reported to have cytokinin activity in 1982. Since then, thidiazuron has been used successfully in vitro to induce adventitious shoot formation and to promote axillary shoot proliferation. Thidiazuron is especially effective with recalcitrant woody species. Shoot numbers produced on medium containing thidiazuron are equivalent to or greater than numbers initiated on medium with purine-type cytokinins. Low concentrations of thidiazuron (0.0022 to 0.088 mg/liter) are effective for micropropagation. Prolonged exposure to thidiazuron should be avoided, as this may cause hyperhydricity, abnormal shoot morphology, or problems in rooting. Presented in the Session-in-Depth Novel Plant Growth Regulators at the 1992 World Congress on Cell and Tissue Culture, Washington, D.C., June 20–25, 1992.     

Acoustic response properties of single units in the torus semicircularis of the goldfish,Carassius auratus

Single units of the goldfish torus semicircularis (TS) were recorded in response to pure tones. Response areas (RA) were obtained by recording the number of spikes evoked by tones in a range of frequencies and levels within the units' dynamic range. RAs gave estimates of best sensitivity (BS), characteristic frequency (CF), most excitatory frequency at each level (BF), and Q_10dB. Peri-stimulus-time histograms (PSTH), interspike interval histograms (ISIH), and period histograms were obtained at various frequencies and levels to describe the units' temporal response patterns.The distribution of CF is nonuniform with modes at 155, 455, and 855 Hz. The distribution of the coefficient of synchronization to standard tones is also nonuniform, revealing a dichotomy between units with little or no phase-locking and those that phase-lock strongly. PSTHs for units without significant phase-locking vary widely and include patterns resembling those of the mammalian auditory brainstem. Compared with saccular afferents, torus units tend to have lower spontaneous rates, greater sensitivity, and sharper tuning. Unlike saccular afferents, BF is independent of level for most torus units. Some torus units are similar to saccular afferents while others reveal significant transformations of information between the periphery and the midbrain.Abbreviations BF best frequency - BS best sensitivity - CF characteristic frequency - ISIH inter-spike interval histogram - PSTH peri-stimulus-time histogram - RA response area - TS torus semicircularis