X-ray structure of beta-cyclodextrin-2,7-dihydroxy-naphthalene.4.6 H(2)O: an unusually distorted macrocycle.

The inclusion complex beta-cyclodextrin.2,7-dihydroxynaphthalene.4.6 H(2)O crystallized in the monoclinic space group P2(1), with a=14.082(3), b=19.079(4), c=12.417(3) A, beta=109.28(3) degrees, V=3149.0(11) A(3), and Z=2. An X-ray study performed at room temperature shows that the crystal packing is of the herringbone type with one 2,7-dihydroxynaphthalene included completely in the beta-CD cavity, its long axis being oriented along the beta-CD molecular axis, and 4.6 water molecules are placed in the interstitial space. The beta-CD macrocycle is elliptically distorted, and the guest molecule is held in the hydrophobic beta-CD cavity by C-H...O and C-H...pi interactions.     

Sr2+ induces unusually stable d(GGGTGGGTGGGTGGG) quadruplex dimers

Guanine‐rich sequences are able to form quadruplexes consisting of G‐quartet structural units. Quadruplexes play an important role in the regulation of gene expression and have therapeutic and biotechnological potential. The HIV‐1 integrase inhibitor, (GGGT)₄, and its variants demonstrate unusually high thermal stability. This property has been exploited in the use of quadruplex formation to drive various endergonic reactions of nucleic acids such as isothermal DNA amplification. Quadruplex stability is mainly determined by cations, which specifically bind into the inner core of the structure. In the present work, we report a systematic study of a variant of the HIV‐1 integrase inhibitor, GGGTGGGTGGGTGGG (G3T), in the presence of alkali and alkaline‐earth cations. We show that Sr²⁺‐G3T is characterized by the highest thermal stability and that quadruplex formation requires only one Sr²⁺ ion that binds with low micromolar affinity. These concentrations are sufficient to drive robust isothermal quadruplex priming DNA amplification reaction. The Sr²⁺‐quadruplexes are also able to form unusually stable dimers through end‐to‐end stacking. The multimerization can be induced by a combination of quadruplex forming cations (i.e., K⁺ or Sr²⁺) and non‐specific Mg²⁺.     

The action of FMRFamide (Phe-Met-Arg-Phe-NH2) and related peptides on mammals

First purified 11 years ago from clam ganglia, FMRFamide (Phe-Met-Arg-Phe-NH2) was quickly demonstrated to be cardioactive in several molluscan species. Subsequent discovery that FMRFamide, or FMRFamide-related peptides (FaRPs), were present in mammalian central nervous system and gastrointestinal tract prompted investigations into the effect of FMRFamide on mammals. FMRFamide has now been shown to be cardioexcitatory in mammals, to inhibit morphine-induced antinociception, and to block morphine-, defeat-, and deprivation-induced feeding. It also inhibits colonic propulsive motility, induces behavioral effects when administered intrathecally, and has been reported to have amnesic effects in rodents. A proposal has arisen that a FMRFamide-like substance is an endogenous opioid antagonist and has stimulated a search for such a substance. However, FMRFamide has only weak affinity for opioid receptors and not all the actions of FMRFamide appear to be explained by actions at opioid receptors. Alternative mechanisms have been proposed which suggest that FMRFamide acts as a neuromodulator.     

The Influence of CO(2) Supply on Colonial Formation of Leptospires

The colonial formation of three serotypes of Leptospires on Cox's solid medium was promoted by microaerophilic incubation of one to three per cent of CO(2) supplied by carbon dioxide cylinder, sodium carbonate oxalic acid, and candle method. In anaerobic incubation Leptospira pomona grew the same as with CO(2) incubation. The pH of the medium was an important influence on the rate of colonial formation of Leptospires. Addition of hemoglobin and inactivation of rabbit serum was not an essential condition for rapid colonial formation. It was found that variation in the morphology of leptospiral colonies occurred with hemoglobin from different species and individuals.     

Probable genetic linkage between autosomal dominant retinitis pigmentosa (RP) and amylase (AMY2): evidence of an RP locus on chromosome 1.

A linkage analysis is reported for three branches of a single family segregating for autosomal dominant retinitis pigmentosa. A statistically significant lod score of 3.9 is obtained for the RP locus and AMY2 at a recombination frequency of 1%. This linkage indicates that the RP locus is on the no. 1 chromosome since the AMY2 locus has been placed on the short arm of 1. Lod scores are reported for four other loci on chromosome 1; none of these achieve statistical significance. Analyses are reported for 23 additional autosomal markers and close linkage with RP can be excluded for a number of these.     

The action of phospholipase C on ethanolamine plasmalogen (2-acyl-1-alkenylglycerylphosphorylethanolamine)

1. The phospholipase C of Bacillus cereus attacks the ethanolamine plasmalogen of brain to yield a plasmalogenic diglyceride (2-acyl-1-alkenylglycerol). 2. This plasmalogenic diglyceride is analogous to the material obtained by the action of the phospholipase C of Clostridium welchii on the choline plasmalogen of heart.     

The anomalous reactivity of the bis(dibutylstannylene) acetal of pentaerythritol: a case of triple activation

The only dibutyltin derivative of pentaerythritol which is observed by refluxing with dibutyltin oxide in methanol is a bis(dibutylstannylene) acetal. This is converted to the expected dibenzyl ether with benzyl bromide, in the presence of tetraethylammonium bromide in boiling toluene, but benzoylation at room temperature gives a tribenzoate. A mechanism is suggested to account for this triple activation.     

The human factor H-related gene 2 (FHR2): structure and linkage to the coagulation factor XIIIb gene

The human factor H-related gene 2 (FHR2) encodes a serum protein structurally and immunologically related to complement factor H. We describe the isolation and genomic organization of the human FHR2 gene from a yeast artificial chromosome library. The FHR2 gene is organized in five exosn and span about 7 kilobases (kb) of human genomic DNA. A comparison with the corresponding cDNA sequence (clone DDESK59) shows that the analyzed FHR2 gene has a deleted region within exon 4. A new splice acceptor site created in the truncated exon indicates that the analyzed gene could be translated to a truncated protein. Further, we demonstrate that the genes for FHR2 and subunit of coagulation factor XIII are located in the same 165 kb YAC DNA. Thus, the three structurally related genes FXIIIb, FHR2, and factor H are linked on human chromosome 1 in the regulators of complement activiation (RCA) gene cluster. The physical linkage of the FHR2 and the factor H genes provides additional evidence for a close relatedness of complement factor H and the factor H-related proteins. The linkage and the almost exclusive organization in short consensus repeat-containing domains indicates a close evolutionary relationship of the FXIIIb, FHR2, and factor H genes.The nucleotide sequence data reported in this paper have been submitted to the EMBL and GenBank nucleotide sequence databases and have been assigned the accession number X86564 (exon 1), X86565 (exon 2), X86566 (exon 3 and 4), and X86567 (exon 5)     

Towards an integrated linkage map of common bean 2. Development of an RFLP-based linkage map

Summary A restriction fragment length polymorphism (RFLP)-based linkage map for common bean (Phaseolus vulgaris L.) covering 827 centiMorgans (cM) was developed based on a F₂ mapping population derived from a cross between BAT93 and Jalo EEP558. The parental genotypes were chosen because they exhibited differences in evolutionary origin, allozymes, phaseolin type, and for several agronomic traits. The segregation of 152 markers was analyzed, including 115 RFLP loci, 7 isozyme loci, 8 random amplified polymorphic DNA (RAPD) marker loci, and 19 loci corresponding to 15 clones of known genes, 1 virus resistance gene, 1 flower color gene, and 1 seed color pattern gene. Using MAPMAKER and LINKAGE-1, we were able to assign 143 markers to 15 linkage groups, whereas 9 markers remained unassigned. The average interval between markers was 6.5 cM; only one interval was larger than 30 cM. A small fraction (9%) of the markers deviated significantly from the expected Mendelian ratios (121 or 31) and mapped into four clusters. Probes of known genes belonged to three categories: seed proteins, pathogen response genes, and Rhizobium response genes. Within each category, sequences homologous to the various probes were unlinked. The I gene for bean common mosaic virus resistance is the first disease resistance gene to be located on the common bean genetic linkage map.