Isolation of eukaryotic ribosomal proteins. Purification and characterization of the 60 S ribosomal subunit proteins L4, L5, L7, L9, L11, L12, L13, L21, L22, L23, L26, L27, L30, L33, L35', L37, and L39.

The proteins of the large subunit of rat liver ribosomes were separated into seven groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5. Seventeen proteins (L4, L5, L7, L9, L11, L12, L13, L21, L22, L23, L26, L27, L30, L33, L35', L37, and L39) were isolated from three of the groups (B60, D60, G60) by ion exchange chromatography on carboxymethylcellulose and by filtration through Sephadex. The amount of protein obtained varied from 0.5 to 15 mg. Eight of the proteins (L9, L11, L13, L21, L22, L35', L37 and L39) had no detectable contamination; the impurities in the others were no greater than 9%. The molecular weight of the proteins was estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate; the amino acid composition was determined.     

TENACITY OF ATTACHMENT IN TWO SPECIES OF LITTORINID, LITTORINA LITTOREA (L.) AND LITTORINA OBTUSATA (L.)

Here we present data concerning the ability of two littorinidsto remain attached to a slate substratum as a dislodging forceis applied vertically. Specimens of Littorina littorea (L.)and L. obtusata (L.) were attached to a simple pulley and sandflowsystem which applied force to the animals at a constantly increasingrate until the animals released from the substratum. Three aspectsof tenacity were measured: force required to remove the winklesfrom the substratum; time taken for removal; and final displacementat removal. For L. littorea the mean force required (1.09 N),the mean displacement (8.9 mm) and the mean time taken (185s) were all found to be significantly greater than those recordedfor L. obtusata (means = 0.60 N, 7.5 mm and 102 s, respectively).However, when animal size was taken into account there was nosignificant difference in either force or time required forremoval, although L. obtusata showed a greater displacementthan did L. littorea. Animal dry flesh weight was not a usefulpredictor of any of the tenacity variables. Rugosity of theslate substrata was shown to have a significant effect on alltenacity variables, greater forces being required to removeboth species of winkle from smooth substrata than from roughsubstrata. This also generally held true when animal size wasaccounted for. The results of these experiments, although insufficientto identify the mechanism(s) of attachment, do discount themechanism of ‘muscular grip’, since greater tenacitywould be expected on rough substrata. Whether winkles were immersedor emersed had no significant effect on any of the tenacityvariables. Recorded tenacities suggest that many L. littoreaand L. obtusata would be dislodged by the direct forces createdby breaking waves. (Received 5 August 1996; accepted 18 November 1996)     

水深、基质、光和去苗对菹草石芽萌发的影响

通过野调查,研究了水深对菹草石芽萌发率的影响,比较了梁子湖与湖北省其他四个不同水深的湖泊间菹草石芽明发率月动态;并通过萌发实验探讨了基质、光和去苗对菹草石芽萌发的影响。结果如下：无光环境下菹草石芽的萌发率较有光下的小,基质的有无及其类型对萌发率影响不大,去苗能使其萌发第二苗和第三苗的百分离分别从自然状态下的3．2％和1．0％提高至96．8％和64．0％（12月初）;五个湖泊的石芽均于7月初即开始萌发,相同月份不同湖泊石芽的平均萌发率基本与其平均水深成负相关关系,但12月初各湖泊的平均萌发率相近（＞95％）;同一湖泊水深越大,相同月份的萌发率越低,水深的增加能显著推迟萌发起始时间,但不改变其最终萌发率（12月初＞95％）。菹草石高萌发率的特征和极高的萌发第二、第三苗的潜力可能是其成为许多湖泊优势种的两个极其重要的维持机制。     

THE WEB-SPINNING PROCESS AND WEB-STRUCTURE OF LATRODECTUS TREDECIMGUTTATUS, L. PALLIDUS AND L. REVIVENSIS

The web structure and the web spinning process of Latrodectus tredecimguttatus Rossi, Latrodectus pallidus Cambridge and Latrodectus revivensis Shulov have been investigated, particular attention being given to the structure of their catching webs.
The webs of Latrodectus represent a further development of the web-type of Archaeranea tepidariorum . The specific characters of the investigated webs concern the middle layer of their three-layer webs, where more or less regular structures appear.
In the middle layer of L. tredecimguttatus web paths of hexagonal meshes appear.
In the web of L. pallidus and L. revivensis more or less regular radially arranged catching platforms appear, connected with the distant retreat by a long bridge-web.
The lower layer of vertical threads, with viscid droplets on their far ends is spread-out in L. tredecimguttatus and consists of short threads as distinct from the concentrated bundle of high threads in the two other species.
Since L. pallidus and L. revivensis appear usually among vegetation, their restricted catching webs seem to be adaptive adjustment to the biotope.
The concentration of the catching webs brings about improvement as regards prey detection.
The differences in the web structure of L. tredecimguttatus and L. revivensis indicate that their behavioural characters are more distinct than the morphological ones. The different behavioural characters support the view that L. revivensis represents a species different from L. mactans tredecimguttatus .     

A FINE STRUCTURAL ANALYSIS OF THE EPIDERMIS OF THE EARTHWORM, LUMBRICUS TERRESTRIS L

A fine structural analysis of the cuticle, epidermal epithelium, and underlying fibrous tissue of the earthworm is presented. The extreme scarcity or absence of fibroblasts in this animal is pointed out. This finding is further evidence for the epithelial origin of the cuticular fibers, and suggests that at least some of the collagenous connective tissue fibers in the interior of this animal are epithelial in origin. The junctional specializations that unite epithelial cells in the epidermis and intestine are described. Of special interest is the fact that the septate desmosome rather than the tight junction is found in these epithelia. It is shown that the septa are not extensions of the plasma membrane across the intercellular gap. Finally, the nature of the small ellipsoidal bodies that are embedded in the outer layer of the cuticle is discussed.     

Sequence of the amino-terminal region of rat liver ribosomal proteins S4, S6, S8, L6, L7a,L18, L27, L30, L37, L37a,and L39

The sequence of the amino-terminal region of eleven rat liver ribosomal proteins–S4, S6, S8, L7a, L18, L27, L30, L37a, and L39 - was determined. The analysis confirmed the homogeneity of the proteins and suggests that they are unique, since no extensive common sequences were found. The N-terminal regions of the rat liver proteins were compared with amino acid sequences in Saccharomyces cerevisiae and in Escherichia coli ribosomal proteins. It seems likely that the proteins L37 from rat liver and Y55 from yeast ribosomes are homologous. It is possible that rat liver L7a or L37a or both are related to S cerevisiae Y44, although the similar sequences are at the amino-terminus of the rat liver proteins and in an internal region of Y44. A number of similarities in the sequences of rat liver and E coli ribosomal proteins have been found; however, it is not yet possible to say whether they connote a common ancestry.     

獐牙菜属植物的研究概况

本文对龙胆科獐牙菜属植物的化学和生理活性研究进行了概略的回顾。迄今为止,约有40种獐牙菜属植物有文献报道。从这些植物中已分离出100多种不同类型的化合物,包括(口山)哃、黄酮、甙类、萜类及少部分内酯、生物碱和有机酸类化合物。这些化合物有多种生理活性,如:镇静、抗结核菌、强壮、退热、轻泻、肝保护、抗惊厥、增压及治疗胃病和心血管疾病等。还可制成各种制剂用于生发、护肤、驱虫等。     

悬钩子属和蔷薇属的新植物

本文发表了山莓两个新变型和小果蔷薇一新变型,即粉红山莓Rubus corchorifolius L.f.f.roseolus Z.X.Yu、重瓣山莓R.cor-chorifolius L.f.f.Hemi semiplenus Z.X.Yu,还有重瓣小果蔷薇Rosa cymosa Tratt.f.plena Z.X.Yu et G.Z.Liu。     

中国七星瓢虫群聚和迁飞的数学分析

自1976年首次在秦皇岛海岸发现七星瓤虫的群聚现象以来,又经过连续8年的广泛研究,进一步讨论了七星瓤虫在黄、渤海域的群聚范围、群聚数量、群聚规律以及迁飞等问题。本文的重点是试图从数学上论证七星瓤虫的迁飞,并进一步预测预报七星瓤虫的群聚日期,以便为群聚七星瓢虫的利用奠定基础。 根据可能有关的因子设64个自变量,2个因变量,通过反复计算,大量筛选可能与虫情有关的气象因子,结果入选的气象因子说明,群聚瓢虫是迁飞过程中迫降入海,并由风浪推上海岸的。经过用双层筛选逐步回归和逐步判别两种数学方法去筛选自变量,结果基本上是一致的。因此从定量角度对七星瓢虫的群聚和迁飞给出了论证。并说明七星瓢虫的群聚与近期气象条件密切相关,可以利用短期或中期气象预报代入判别式进行群聚的预测预报。     

CYCLING OF Mn,Fe, Cu AND Zn BY EELGRASS,ZOSTERA MARINA L

Significant (P < 0.005) differences in Mn, Fe, Cu and Zn concentrations were found in different parts of eelgrass plants; i.e., roots and rhizomes, live blades, attached dead blades, and detritus. Imported vs. exported suspended particles of eelgrass blades did not differ in Mn, Fe, Cu or Zn content. Significant location effects, which varied with the type of plant tissue, were noted for Mn, Fe, Cu and Zn for three grass beds in the vicinity of Beaufort, NC. In simplified Mn, Fe, Cu and Zn budgets, eelgrass biomass is the largest biological reservoir, while eelgrass growth, senescence, and decomposition constitute the largest biological flux of these elements in this ecosystem.     

河北大戟属一新种

本文发表了大戟属一新种, 即紫斑大戟Euphorbia purpureo maculata T.J.Feng et J.X.Huang。     

VASCULARIZATION OF DEVELOPING LEAVES OF GLEDITSIA TRIACANTHOS L. I. THE NODE,RACHIS, AND RACHILLAE

Leaves of Gleditsia triacanthos L. are served by three leaf traces that subdivide in the node to produce subsidiary bundles. The subsidiary bundles differentiate basipetally in the stem and acropetally in the petiole using the original leaf trace bundles (those that developed acropetally) as templates for their development. Within the pulvinus, the acropetal bundle components merge to form the rachis vasculature consisting of a semicircular arc and a ventral chord; several small bundles diverge to form ventral ridge bundles. Mixing of bundles occurs during vascularization of the lateral rachillae axes. Each diverging rachilla axis receives bundles from the semicircular arc, the ventral chord, and a ridge bundle in a relatively reproducible and predictable pattern. During this process the main rachis vasculature is gradually depleted, but the ridge bundles are reconstituted following divergence of each rachilla pair. The distal rachilla pair is vascularized by a bilateral partitioning of the entire rachis vasculature; a remnant of the central leaf trace terminates in a subulate terminal appendage. Vascularization of the bipinnate G. triacanthos leaf is compared to that of the simple Populus deltoides leaf.