Calcium binding decreases the stokes radius of calmodulin and mutants R74A, R90A, and R90G.

Calmodulin (CaM) is an intracellular cooperative calcium-binding protein essential for activating many diverse target proteins. Biophysical studies of the calcium-induced conformational changes of CaM disagree on the structure of the linker between domains and possible orientations of the domains. Molecular dynamics studies have predicted that Ca4(2+)CaM is in equilibrium between an extended and compact conformation and that Arg74 and Arg90 are critical to the compaction process. In this study gel permeation chromatography was used to resolve calcium-induced changes in the hydrated shape of CaM at pH 7.4 and 5.6. Results showed that mutation of Arg 74 to Ala increases the R(s) as predicted; however, the average separation of domains in Ca4(2+)-CaM was larger than predicted by molecular dynamics. Mutation of Arg90 to Ala or Gly affected the dimensions of apo-CaM more than those of Ca4(2+)-CaM. Calcium binding to CaM and mutants (R74A-CaM, R90A-CaM, and R90G-CaM) lowered the Stokes radius (R(s)). Differences between R(s) values reported here and Rg values determined by small-angle x-ray scattering studies illustrate the importance of using multiple techniques to explore the solution properties of a flexible protein such as CaM.     

A cointegrate of the bacteriophage P1 genome and the conjugative R plasmid R100

Restriction cleavage analysis identified a P1CmSmSuTc plasmid isolated by Mise and Arber (1976) (Virology 69, 191–205) as a cointegrate between bacteriophage P1 and the R plasmid R100. Cointegration occurred by reciprocal recombination between the IS1 element of P1 and IS1b of R100. It involved neither gain nor loss of genetic material, so that the cointegrate carries three IS1 elements in the same orientation. The cointegrate propagates with relatively high stability as plasmid in Escherichia coli host bacteria. It displays the Tra⁺ functions of R100, incompatibility FII of R100, and incompatibility Y of P1, Res⁺ (P1), Mod⁺ (P1) functions of P1 and P1 immunity. Production of P1 phage particles is inducible as for wild type P1. However, because of the large genome size of 180 kb, progeny phage particles contain only a fraction (about 100 kb) of the cointegrate genome. Because of cyclic permutation all genome regions are equally represented in a population of the phage particles of an induced lysate. Occasionally, reciprocal recombination between IS1 elements allows the restoration of the P1 genome. These segregants are found as plaque formers at a rate of about 1 per 300 phage particles in induced lysates.     

A simple R banding technic.

A simplified R banding technic is described which provides excellent delineation of major regions, easy identification of all chromosomes, and an accurate comparison of homologue lengths. The technic is simple, requiring only an initial incubation in buffer at 85 degrees C followed by acridine orange staining. The best presentation of the R banded chromosomes was obtained by printing in black and white from color transparency film. Variations in the length of the short arms of the acrocentric chromosomes are clearly and consistently defined. Satellites are not demarcated and appear as part of the short arm. Consistent banding was obtained, and the technic is suitable for use in routine clinical cytogenetic work.     

A cytogenetic study of R. constantinopolitanus and R. sericeus (Ranunculaceae) in Iran

With 600 species Ranunculus is the largest genus in Ranunculaceae, and has a broad global distribution. We studied the karyotypes of R. constantinopolitanus and R. sericeus species of Ranunculaceae and identified their symmetry level. New chromosome numbers of 2n = 21 (Nodeh woods population) and 2n ca. 63 (Javaherdeh population) are reported for R. constantinopolitanus. Two different populations of R. sericeus had two different chromosome results. We investigated morphological and karyological studies along with pollens micromorphology. Different populations of R. constantinopolitanus and R. sericeus, with different chromosome numbers showed morphological and micromorphological differences. Therefore, we considered the two populations of R. sericeus as cytotypes. There was a correlation between the studied morphological characters and pollen size with ploidy levels in the two R. constantinopolitanus populations.     

R－A型甜菊糖甙的研制

以甜菊（ＳｔｅｖｉａｒｅｂａｕｄｉａｎａＢｅｒｔｏｎｉ）的干叶为原料生产的甜菊糖甙是一种食用天然甜味剂。提高甜菊糖甙（Ｓｔｅｖｉｏｓｉｄｅｓ）中优质甜味成分Ｒ－Ａ（甜菊Ａ３甙：ＲｅｂａｕｄｉｏｓｉｄｅＡ）的含量比例是生产中急待解决的课题。本文以Ｒ－Ａ型和Ｓｔ（甜菊甙Ｓｔｅｖｉｏｓｉｄｅ）型甜菊叶为原料,采用Ａ和Ｂ两种方法进行甜菊糖甙的提取,通过Ｂ法获得Ｒ－Ａ含量比例高的甜菊糖甙即Ｒ－Ａ型甜菊糖甙,为甜菊糖甙产品优质化提供了新方法、新技术     

T. R. R. Stebbing:A bibliography with biographic notes

T. R. R. Stebbing (1835–1926), a specialist on the systematics of amphipod Crustacea, was raised in London in a literary family and studied classics, law and history at Oxford. After his ordination as a priest in 1859 he was a schoolmaster, then, after he married, a private tutor at Torquay. About 1863 he read Darwin's Origin of species and was convinced by it; by 1868 he had become a naturalist and systematist. In 1877 he moved to Tunbridge Wells where he spent the rest of his life studying Crustacea, active in scientific societies, and writing essays and reviews.
Stebbing's Darwinism was not particularly original, though he marshalled some good examples from the invertebrates to indicate the importance of variation within and between species. He regarded natural selection as a directing force by which God's plan for organisms was being worked out, and credited it with the origin of language, morality and religion. In taxonomic practice, Stebbing advocated priority of names, simple rules of transliteration and gender, and publication of new names only in a few easily-accessible journals. After the publication of the Regies internationales de la nomenclature zoologique in 1905 his writings on taxonomic practice were confined to minor issues.
A bibliography of Stebbing's 242 publications concerned with carcinology, Darwinism, nomenclature and miscellaneous subjects has been compiled.     

A PANEL PERFORMANCE PROCEDURE IMPLEMENTED IN R

Monitoring performance is essential for the efficient use of a sensory panel both during training and while carrying out product assessments. We present a concise procedure to monitor panel performance based on classical statistical methods. The program includes tests for the ability to discriminate between products, repeatability of assessments, scale use, agreement between panelists and a principal component analysis map of panelist means across attributes. The algorithm is implemented in R – a state‐of‐the‐art, freely available statistical software package. The program output is summarized in graphs and tables. This easily applicable panel performance procedure is aimed at improving sensory practice, especially in areas where the use of highly complex systems is not feasible.