Postmolt cuticle growth in a cockroach: in vitro deposition of multilamellate and circadian-like layered endocuticle

Summary Pieces of the hind legs of freshly moltedBlaberus craniifer adults were cultivated in vitro. The deposition of multilamellate and circadian-like layered endocuticle was observed. In multilamellate cuticle, the number of double lamellae was frequently much greater than the number of days in culture. In circadian-like layered cuticle, the number of double layers corresponded to the numbers of days in culture, or it was smaller.I am indebted to Mrs Hassenrück, for excellent assistance. — Supported by the Deutsche Forschungsgemeinschaft (We 389/12-2).     

Elemental compartmentalization in seeds of Atriplex triangularis and Atriplex confertifolia

Seeds of two halophytes, Atriplex triangularis, which grows in a mesic saline marsh environment, and Atriplex confertifolia, which grows in a xeric desert environment, were analyzed by energy-dispersive X-ray microanalysis for the distribution of elements. The highest concentration of sodium, chlorine, potassium, and calcium was present in seed coats of A. triangularis. All of the elements detected were at low concentrations in the endosperm. Embryos contained the highest amount of phosphorus that is probably associated with organophosphate compounds. Potassium was also high in embryos. The total amount of elements in all regions of A. confertifolia was low as compared to A. triangularis. In a similar pattern sodium, chlorine, potassium, and calcium were the highest in seed coats of A. confertifolia. Elemental concentration was also low in the endosperm. Likewise, the phosphorus level was the highest in the embryo. The results support the concept of elemental compartmentalization in seeds of these halophytes.     

Computer analysis of cross sections of leaves of Chrysothamnus taxa and their relation to environmental conditions

Thirty-eight accessions of 20 taxa (species and subspecies) of Chrysothamnus from a range of environments were grown in a uniform garden. During mid-June, terminal and lateral leaves were removed, fixed, and processed for light-microscopy studies. Area and perimeter measurements of ink tracings of midleaf vein cross sections were measured using computer-scan techniques. Leaf area and perimeter were compared with vein perimeter and area measurements. Area and perimeter of these Chrysothamnus leaves varied in response to the environment at the collection location. Plants native to hot, dry conditions had small, thick leaves, whereas plants native to cooler, more mesic conditions had relatively large, thin leaves. Similarly, leaves with round veins were adapted to hot, dry environments and leaves with elliptical veins were adapted to cooler, more mesic environments. Both terminal (young) and lateral (older) leaves were sampled. Terminal leaves showed significant (p < .05) correlational responses to environmental parameters, whereas the lateral leaves, while fronding in the predicted morphological directions, did not generally show significant responses. The different responses of terminal and lateral leaves may have been due to canopy position and uniform environmental conditions of the garden. Leaves with large cross sections characteristically had large veins, and leaves with small cross sections characteristically had small veins. Large leaf cross sections were normally flat. Small leaf cross sections were normally round. Decreasing leaf size and increasing leaf thickness were correlated with aridity.     

面向表单的分析：一种基于表单的应用程序模型的新方法

在软件工程中，企业系统最为吸引人也是最为需求的。本书对企业系统建模作概念性的介绍和全面地综述。提出了分析与设计基于表单的企业系统的一种特殊目的建模技术。对特殊领域建模语言一直存在着强烈的需求。本书的作者来自科学家和对此类商业应用程序有兴趣的专业人员，他们以一种创新的方法修改了已被广泛接受的基本建模技术，实现对所需应用程序领域建模框架的优化。     

A practicable variant of the ion exchange method for the radiometric estimation of ornithine decarboxylase activity

Summary A known ornithine decarboxylase assay working with ion exchang separation of [³H]ornithine and [³H]putrescine has been revised. The assay can be performed in disposable 1.5 ml vessels with a total of four pipetting steps. The separation of enzyme substrate and product, respectively, requires 3 h per 50 samples. The detection limit is about 50 pmoles [³H]putrescine formed.     

Amino-terminal fragments of Escherichia coli lac repressor bind to DNA.

The N-terminal fragments (residues 1-51 and 1-59) obtained by selective tryptic cleavage of native lac repressor retain the ability to bind DNA. These fragments (headpieces) are monomeric and form complexes which resemble those of tetrameric repressor with non-operator DNA. But, they do not show the high specificity of repressor for operator sequences. The DNA binding has been demonstrated by filter-binding assay as well as in solution using absorption, circular dichroism, and fluorescence measurements.     

Influence of the thymus hormone on radioleucosis in mice]

A partially purified thymic extract has determined the development of leucosis in 10 thymectomized irradiated CC57Bl mice out of 25. The pure hormone isolated from the same extract prevented the development of leucosis in intact irradiated Mice. This seems to indicate the presence of a second active substance in the extract (enhancing the development of the leucosis).     

The structure of locomotor activity in bilobectomized cockroaches (Blaberus fuscus)

Summary The aperiodic activity patterns of bilobectomized cockroaches can largely be described by simple stochastic regularities: a) there are no correlations between the lengths of successive activity bursts and rest pauses, b) the probabilities for the transition from activity to rest and from rest to activity are time-independent. The activity sequence is strongly influenced by singular temperature steps or temperature cycles.     

Polymorphism near the rat prolactin gene caused by insertion of an Alu-like element

Primate Alu and rodent Alu-like elements comprise major families of mammalian small dispersed repetitive DNAs. These elements are repeated more than 10(5) times per haploid genome and are found between known genes, in introns and in satellite DNA. Their dispersion throughout the genome and the presence of directly repeated DNA sequences flanking the elements suggest, but do not prove, that they are capable of transposition. We describe here an allelic variation in the 5'-flanking region of the rat prolactin gene that offers the opportunity to examine the sequences of matching regions of two homologous chromosomes which differ in the presence of an Alu-like repetitive DNA element. Our findings support the hypothesis that these elements are integrated into the genome by generating short direct repeats of host DNA.